THEORIES OF STAINING Biological Staining
Structural Components (Nature) Of Stains
Staining Mechanism
Metachromasia
Types Of Staining
Staining of Paraffin Section
A stain is any colouring organic compound that combined with another substance imparts a colour to that substance.
The term ‘dye’ is used to refer to a colouring agent that is used for general purposes, whereas the term ‘stain’ is used to refer to that dye which is used for biological purposes.
The stains used for bacteria are aniline dyes they are derived from aniline (C6H5NH2).
The most commonly used aniline dyes are crystal violet, methylene blue, basic fuchsin, safranin, eosin, etc.FACTORS INFLUENCING METACHROMASIA
The tissue section is colourless because the fixed protein has the same refractive index as that of glass. We use dyes that have specific affinity with the different tissue proteins and colour them differently.
Colour is seen by the eye as a result of the effect of certain electromagnetic waves on the rods and cones of the retina. These waves, which have a varying length, will determine the colour that is seen.
White light being composed of all the colours of the visible spectrum varies in wavelength from 4,000 Â to 8,000 Â.
If light of a specific wavelength is absorbed from white light the resultant light will then be coloured, the colour being dependent upon the particular wavelength that has been removed.
The tissue section is colourless because the fixed protein has the same refractive index as that of glass. We use dyes that have specific affinity with the different tissue proteins and colour them differently.
Colour is seen by the eye as a result of the effect of certain electromagnetic waves on the rods and cones of the retina. These waves, which have a varying length, will determine the colour that is seen.
White light being composed of all the colours of the visible spectrum varies in wavelength from 4,000 Â to 8,000 Â.
If light of a specific wavelength is absorbed from white light the resultant light will then be coloured, the colour being dependent upon the particular wavelength that has been removed.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
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This presentation deals tissue processing in histopathology, the detailed of presentation given blow:
Histology, study the organization of tissues at all levels, from the whole organ down to the molecular components of cells that are found in most multicellular plants and animals.
Animal tissues are classified as epithelium, with closely spaced cells and very little intercellular space; connective tissue, with large amounts of intercellular material; muscle, specialized for contraction; and nerve, specialized for conduction of electrical impulses. Blood is also sometimes considered a separate tissue type.
Plants are composed of relatively undifferentiated tissue known as meristematic tissue; storage tissue or parenchyma; vascular tissue; photosynthetic tissue or chlorenchyma and support tissue or sclerenchyma and collenchyma.
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
This presentation deals tissue processing in histopathology, the detailed of presentation given blow:
Histology, study the organization of tissues at all levels, from the whole organ down to the molecular components of cells that are found in most multicellular plants and animals.
Animal tissues are classified as epithelium, with closely spaced cells and very little intercellular space; connective tissue, with large amounts of intercellular material; muscle, specialized for contraction; and nerve, specialized for conduction of electrical impulses. Blood is also sometimes considered a separate tissue type.
Plants are composed of relatively undifferentiated tissue known as meristematic tissue; storage tissue or parenchyma; vascular tissue; photosynthetic tissue or chlorenchyma and support tissue or sclerenchyma and collenchyma.
H and E staining is most important part of the histopathological diagnosis, this presentation is to highlight some important basic concept of the Staining.
Reactive dyes, which are highly-coloured organic substances, are used to colour textile dyes. Reactive dyes are chemical reactions that occur when reactive dyes are applied to fiber. Covalent bonds are formed between the dye molecule and the fiber. This is one of strongest chemical reactions. It ensures that the colouring remains permanent.
Sanjo College of Pharmaceutical Studies, Physical Pharmaceutics I , 3rd semester B.Pharm, Complexation & protein binding, Classification in detail, determination methods, application of complexes in pharmacy.
Stain/certified fixed orthodontic courses by Indian dental academyIndian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and
offering a wide range of dental certified courses in different formats.for more details please visit
www.indiandentalacademy.com
Definition
General properties
Composition
Function of saliva
Formation of saliva
Method for collecting saliva
Advantages
Limitations
Analysis of saliva done for the diagnosis of systemic disease
Definition:
by Stedmann’s & Lipincott medical dictionary.
A clear, tasteless, odourless, slightly acidic (pH 6.8) viscous fluid, consisting of the secretion from the parotid, sublingual, submandibular salivary glands and the mucous glands of the oral cavity.
General properties
Volume: 1000 to 1500 mL of saliva is secreted per day and, it is approximately about 1 ml/ minute.
Contribution by each major salivary gland is:
i. Parotid glands: 25%
ii. Submandibular glands: 70%
iii. Sublingual glands: 5%.
Reaction: Mixed saliva from all the glands is slightly acidic with pH of 6.35 to 6.85.
Specific gravity: It ranges between 1.002 and 1.012.
Tonicity: Saliva is hypotonSalivary flow
The average person produces approximately 0.5 L – 1.5 L per day
Unstimulated Flow (resting salivary flow―no external stimulus)
Typically 0.2 mL – 0.3 mL per minute
Stimulated Flow (response to a stimulus, usually taste, chewing, or medication [eg, at mealtime])
Typically 1.5 mL – 2 mL per minute
INTRODUCTION
Tongue is a muscular organ
Situated in the floor of the mouth
FUNCTION
Taste
Speech
Mastication
Deglutition
EXTERNAL FEATURES
Tongue has
A Root
A tip
A body
ROOT
Is attached to the mandible and soft palate above and hyoid bone below.
These attachments prevent the swallowing of the tongue.
In between the 2 bones it is related to the geniohyoid and mylohyoid muscles.
TIP
Of the tongue forms the anterior free end which lies behind the upper incisor teeth.
BODY
Has
A curved upper surface or dorsum
An inferior or ventral surface MUSCLES OF THE TONGUE
Middle fibrous septum divides the tongue into right and left halves.
Intrinsic muscles
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
Central face begins to develop by 4th week, when olfactory placodes appear on both sides of the frontonasal process.
Gradually both placodes develop to form the median and lateral nasal process.
Upper lip is formed by 6th week by fusion of two median nasal processes in midline and the maxilllary process of the 1st branchial arch.
PRE-NATAL GROWTH AND DEVELOPMENT OF PALATEFormation of primary and secondary palate
Elevation of palatal shelves
Fusion of palatal shelves
Introduction
Epidemiology
Etiology
Manifestations
TNM staging
Squamous cell carcinoma is defined as malignant epithelial neoplasm exhibiting squamous differentiation as characterised by the formation of keratin and/or the presence of intercellular bridges.
( Pindborg et al, 1997).
Occipital (2-4)
Superior nuchal line between sternocleidomastoid and trapezius
Occipital part of scalp
Superficial cervical lymph nodes
Accessary lymph nodes
Mastoid (1-3)
Superficial to sternocleidomastoid insertion
Posterior parietal scalp
Skin of ear, posterior external acoustic meatus
Superior deep cervical nodes Accessary lymph nodes
Preauricular (2-3)
Anterior to ear over parotid fascia
Drains areas supplied by superficial temporal artery
Anterior parietal scalp
Anterior surface of ear
Superior deep cervical lymph nodes
Parotid (up to 10 or more)
About parotid gland and under parotid fascia
Deep to parotid gland
External acoustic meatus
Skin of frontal and temporal regions
Eyelids, tympanic cavity
Cheek, nose (posterior palate)
Superior deep cervical lymph nodes
Facial
Superficial(up to 12)
Maxillary
Buccal
Mandibular
Distributed along course of facial artery and vein
Skin and mucous membranes of eyelids, nose, cheek
Submandibular nodes
Deep
Distributed along course of maxillary artery lateral to lateral pterygoid muscle
Temporal and infratemporal fossa
Nasal pharynx
Superior deep cervical lymph nodesSuperficial
Anterior jugular vein between superficial cervical fascia and infrahyoid fascia
Skin, muscles, and viscera of infrahyoid region of neck
Superior deep cervical lymph nodes
Deep
Between viscera of neck and investing layer of deep cervical fascia
Adjoining parts of trachea, larynx, thyroid gland
Superior deep cervical lymph nodes
Anterior cervical/Superficial
Submental (2-3)
Submental triangle
Chin
Medial part of lower lip
Lower incisor teeth and gingiva
Tip of tongue
Cheeks
Submandibular lymph node to jugulo-omohyoid lymph node and superior deep cervical lymph nodes
Is a phenomenon of reflex sequence of muscle contractions that propels the ingested materials and pooled saliva from the mouth to the stomach.
PATTERNS
Infantile (visceral) swallow
Adult/mature swallow
ADULT SWALLOWING
Is composed of 4 stages
Voluntary
Preparatory phase
Oral or buccal
Involuntary: Controlled By Medulla and Lower Pons
Pharyngeal
b. Oesophageal
• Function
• External features
• Papillae of tongue
• Muscles of the tongue
• Arterial supply
• Venous drainage
• Lymphatic drainage
• Nerve supply
• Histology
• Development of tongue -
Intrinsic muscles
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
- Extrinsic muscles
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
1. Vallate or circumvallate papillae
These are large in size 1-2mm in diameter and are 8-12 in number.
They are situated immediately in front of the sulcus terminalis.
Each papillae are cylindrical projection surrounded by a circular sulcus.
The walls of the papilla are raised above the surface.
2. Fungiform papillae
Are numerous
Near the tip and margins of the tongue, but some of them are scattered over the dorsum.
These are smaller than the vallate papillae but larger than the filliform papillae.
Each papilla consists of a narrow pedicle and a large rounded head.
They are distinguished by their bright red colour.
3. Filliform papillae
Conical papilla
Cover the presulcal area of the dorsum of the tongue and gives it a characteristic velvety appearance.
They are the smallest and most numerous of the lingual papillae.
Each are pointed and covered with keratin
The apex is often split into filamentous processes.
Fifth cranial nerve
Have a large sensory root and a small motor root.
Motor root arises – arises from the lateral aspect of lower pons (cranially) the motor root cross the apex of the petrous temporal bone beneath the superior petrosal sinus, to enter the middle cranial fossa.
Sensory root – arises from the lateral aspect of lower pons (caudally).
RELATIONS
Medially
(a) internal carotid artery
(b) posterior part of cavernous sinus
Laterally - middle meningeal artery
Superiorly - parahippocampal gyrus
Inferiorly
motor root of trigeminal nerve
(b) greater petrosal nerve
(c) apex of the petrous temporal bone
(d) foramen lacerum.OPTHALIMIC DIVISION
Terminal branches of Ophthalmic division of trigeminal nerve, are
1. Frontal
Supratrochlear
Supraorbital
2. Nasociliary
Branch of ciliray ganglion
2-3 long ciliary nerves
Posterior ethmoidal
Infratrochlear
Anterior ethmoidal
3. Lacrimal
Branches
From main trunk
Meningeal branch
Nerve to medial pterygoid
From the anterior trunk
Sensory branch
Buccal nerve
Motor branch
Masseteric
Deep temporal nerve
Nerve to lateral pterygoid
From the posterior trunk
Auriculotemporal
Lingual
Inferior alveolar nerves
COTTON-WOOL APPEARANCE
Active phase showing disorganised bone architecture with numerous, large, multinucleated osteoclasts. The stroma is vascular and fibrous
The late phase features thick trabeculae with a prominent mosaic pattern of prominent, hematoxyphilic, cement lines at the interfaces of episodes of resorption followed by deposition.
Paget disease showing very prominent blue cement lines. The lamellae are arranged haphazardly giving an overall effect of a jigsaw puzzle.
Hume- “caries is essentially a progressive loss by acid dissolution of the apatite component of the enamel then the dentin or of the cementum then dentin.”
According to location:
Pit or Fissure caries
Smooth Surface caries
According to rapidity:
Acute
Chronic
Arrested
According to occurrence:
Primary (Virgin) caries
Secondary (Recurrent) caries
According to the site of occurrence:
Enamel caries
Cemental caries.
Acidogenic [ Miller’s Chemico-parasitic] theory.
Proteolytic theory.
Proteolysis- chelation theory.
The lymphatic system has three functions:
Fluid recovery.
Immunity
Lipid absorption
The lymphatic vessels of the small intestine receive the special designation of lacteals or chyliferous vessels.
The components of the lymphatic system are :-
lymph, the recovered fluid;
Lymphatic vessels, which transport the lymph;
Lymphatic tissue, composed of aggregates of lymphocytes and macrophages that populate many organs of the body; and
Lymphatic organs, in which these cells are especially concentrated and which are set off from surrounding organs by connective tissue capsules.
A Magnified Microscopic Image Is Worth More Than A Thousand Words.
DARK FIELD MICROSCOPE
PHASE CONTRAST MICROSCOPY
POLARIZED LIGHT MICROSCOPY
FLUORESCENT MICROSCOPY
STEREO MICROSCOPE
ELECTRON MICROSCOPY
Maxillary Second Premolar
the maxillary first premolar in function
Less angular ,rounded crown in all aspects.
Single root
Smaller crown cervico occlusally
Root length is as great or greater
BUCCAL ASPECT
Not as long as that of the first premolar
Less pointed
Mesial slope is
shorter than the distal slope
Buccal ridge of the crown may not be so prominent whencompared with the first premolarLINGUAL ASPECT
Lingual cusp is longer making the crown longer on the lingual sideMESIAL ASPECT
Cusps of second premolar are shorter with the buccal and lingual cusps more nearly the same length
Greater distance between cusp tips-that widens the occlusal surface buccolingually
No developmental depression on the mesial surface of the crown as on the first premolar
Crown surface is convex instead
No deep dev. Groove crossing the mesial marginal ridgeOCCLUSAL ASPECT
Outline of the crown is more rounded or oval rather than angular
Central dev. groove is shorter and more irregular
Tendency toward multiple supplementary grooves radiating from the central groove that may extend out to the cusp ridges
Makes for an irregular occlusal surface and gives a very wrinkled appearance
Centered in the maxilla, one on either side of median line, with mesial surface of each in contact with mesial surface of other
Two in number
Larger than the lateral incisor
These teeth supplement each other in function, and they are similar anatomically
Shearing or cutting teeth
Major function is to punch and cut food material during the process of mastication
These teeth have incisal ridges or edges rather than
cusps such as are found on canines & posterior teeth
First evidence of calcification
Crown completion
Eruption
Root completion
3-4 months
4-5 years
7-8 years
10-11 years
PHYSICAL PROPERTIES
CHEMICAL PROPERTIES
STRUCTURE OF ENAMEL
DEVELOPMENT OF ENAMEL
EPITHELIAL ENAMEL ORGAN
AMELOGENESIS
LIFE CYCLE OF AMELOBLASTS
AGE CHANGES IN ENAMEL
DEFECTS OF AMELOGENESIS
CLINICAL IMPLICATIONS
PRENATAL GROWTH OF MANDIBLE
Occurs between the 4th and 7th week of intrauterine life.
4th week of intrauterine life
Formation of the head fold
Following which the developing brain and the pericardium form 2 prominent bulges on the ventral aspect of the embryo.
The 2 bulges are separated from each other by a shallow depression called stomatoedum (corresponding to the primitive mouth).
Floor of the stomatodeum is formed by the Buccopharyngeal membrane, which separates the stomatodeum from the foregut.Soon, mesoderm covering the developing forebrain proliferates, and forms a downward projection that overlaps the upper part of the stomatodeum – this downward projection is called frontonasal process.
Since the formation of various parts of the face involves fusion of diverse components.
Occasionally this fusion can be incomplete give rise to various anomalies
MANDIBULOFACIAL DYSOSTOSIS OR FIRST ARCH SYNDROME
- Entire first arch may remain underdeveloped on one or both sides, affecting
Lower eyelid
Maxilla
Mandible
External ear.
- Prominence of the cheek is absent
- Ear is displaced ventrally and caudally
Face develops in humans between 4th – 10th week of intrauterine life.
prenatal growth of the maxilla
DEVELOPMENT OF UPPER LIP
Development of lower lip
Development of nose
hare lip
OBLIQUE FACIAL CLEFT
macrostomia
lateral facial cleft
microstomia
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
2. CONTENT
1. Biological Staining
2. Structural Components (Nature) Of Stains
3. Staining Mechanism
4. Metachromasia
5. Types Of Staining
6. Staining of Paraffin Section
3. STAINING
A stain is any colouring organic compound that combined with another substance
imparts a colour to that substance.
The term ‘dye’ is used to refer to a colouring agent that is used for general purposes,
whereas the term ‘stain’ is used to refer to that dye which is used for biological
purposes.
The stains used for bacteria are aniline dyes they are derived from aniline (C6H5NH2).
The most commonly used aniline dyes are crystal violet, methylene blue, basic fuchsin,
safranin, eosin, etc.
https://monographs.iarc.fr/ENG/Monographs/vol99/mono99-7.pdf
4. GENERAL THEORY :
Purpose of Staining:
(a) To see organism better
(b) To differentiate one organism from another
(c) To determine particular structures
5. BIOLOGICAL STAINING
DYES ARE CLASSIFIED INTO TWO GROUPES:
1. Natural dyes:
a. Haematoxylin -----from plant
b. Carmine -----------from female cochineal bug
c. Orcein --------------a vegetables dye extract
2. Synthetic: these are derived from hydrocarbon benzene
http://www.biologydiscussion.com/micro-biology/staining/stains-meaning-purpose-and-components-microorganisms/55080
6. STRUCTURAL COMPONENTS (NATURE) OF STAINS:
Stains (dyes) usually have complex molecular structure and are chiefly benzene
derivatives.
A stain consists of three constituents: the organic compound containing a
• Benzene ring
• Chromophore
• Auxochrome
http://www.biologydiscussion.com/micro-biology/staining/stains-meaning-purpose-and-components-microorganisms/55080
7. A. CHROMOPHORE:
Certain chemical group introduced into benzene ring by substitution induce colour
to the compound -reffered as chromphore – resultent structure –chromogen
The absorption of electromagnetic radiations in the UV and visible regions by a
molecule causing electronic excitation where electron moves to higher electronic
energy level from a lower.
A covalently unsaturated group responsible for absorption in the UV or visible
region is known as a chromophore.
E.g:
Active chromophore group -C=C-
nitro grouping -NO2-
azo coupling N=N
8. B. AUXOCHROME
The word auxochrome is derived from two roots. The prefix auxo is from auxein,
and means increased. The second part, chrome means colour, so the basic meaning
of the word auxochrome is colour increaser.
This word was coined because it was noted originally that the addition of ionising
groups resulted in a deepening and intensifying of the colour of compounds.
Auxochromes are groups which attach to non ionising compounds yet retain their
ability to ionise and absorbance of the resulting compound.
–NH3 –COOH –HSO3 –OH
http://www.biologydiscussion.com/micro-biology/staining/stains-meaning-purpose-and-components-microorganisms/55080
9. Thus a stain may be defined chemically as an organic compound containing
both chromophore and auxochrome groups linked to its benzene ring.
10. The ability of a stain to bind macromolecular cellular components such as
proteins or nucleic acids depends on the electrical charge found on the
chromogen portion, as well as on the cellular component to be stained.
11. • when benzene of an organic colourless solvent binds to the nitro group of
chromophore, it results in a yellow coloured compound called
trinitrobenzene
• Here three hydrogen atoms in the benzene molecule are replaced by three
nitro groups.
• Trinitrobenzene is a chromogen but not a stain.
12. • Another hydrogen atom is replaced by an auxochrome group, such as OH, the
compound known as picric acid (trinitrohydroxybenzene) is formed.
• The picric acid is capable of ionization or electrolytic dissociation to form salt
that binds to opposite-charged biological substance
http://www.biologydiscussion.com/micro-biology/staining/stains-meaning-purpose-and-components-microorganisms/55080
13. 1. ELECTROSTATIC BONDING
• The affinity between opposite ionic groups of dye and tissue helps in staining.
• Dyes are classified as acid or basic
• For example, eosin is an acid dye with an affinity for the basic protein of cytoplasm
whereas methyl green is a basic dye which has an affinity for the phosphate groups of
deoxyribonucleic acid of the nucleus.
• Salt linkage and ionic binding are alternative terms to electrostatic binding; the correct
name for the forces involved is Coulombic attraction.
STAINING MECHANISM
Culling’s textbook – Staining and Impregnation
14. Acids have a negative charge(-ve)
• They attach to positive charges, especially hydrogen (H+).
• In an electrical field they migrate to the anode. They are
anions.
• Tissues carrying a positive charge will attract dyes with a
negative charge (i.e. acid dyes); and are termed
acidophilic.
• Examples : phosphates of nucleic acids
sulphate groups of acid mucopolysaccharides.
15. Bases have a positive charge (+ve)
• They attach to negative charges especially hydroxy groups
(OH-).
• They migrate to the cathode. They are cations.
• Tissues carrying a negative charge will attract dyes of
positive charge and are termed basophilic.
• Examples : amino acid such as lysine and arginine
16. 2. HYDROGEN BONDING
• Hydrogen being of single valency, can only bond to one
other atom , usually those of strong electronegative
charge.
• Hydrogen bonding
• Weak
• Occur readily in water
• Will occur between the dye and the water it is
dissolved in
• Water will also compete for hydrogen bonding sites
on the tissue
• Hydrogen bonding is of significance in alcoholic dye
solution
17. 3. VAN DER WAALS FORCES
• These intermolecular forces are polar attractions.
• They are weak and are effective over a very short
distance.
• Attraction are between dipoles, that is molecules
possess separated positive and negative charges.
• Eg : staining of elastic fibers by orcein here elastic
fiber is a hydrophobic protein and orcein is a large
molecule with strong dipole
18. 4. COVALENT BONDING
• Covalent bonding involves sharing electrons
• Eg. In water each of two hydrogen atoms shares
an electron with oxygen, and oxygen atom
likewise shares the two hydrogen electrons.
• Here 2 atoms share 2, 3 or more electron pairs,
leading to multiple covalent bond.
• Significance in mordant dying
19. 5. HYDROPHOBIC BONDING
• In an attempt to isolate themselves from surrounding water
molecules, reactive hydrophobic dye molecules will
become bound to reactive hydrophobic tissue groups.
• This reaction is possible between dyes in aqueous solution-
alcohol in the water will form hydrogen bonds with the
water thus inhibiting hydrophobic effect.
20. 6. DYE AGGREGATION
• Dye molecules –have affinity for each other.
• Aggregated dyes penetrate less easily in the tissue than the dispersed dye
• Factors influencing dye aggregation
• large molecular size
• Increased concentration
• Ionic strength
• Low temperature
• Useful in case of metachromasia
21. 7. TISSUE PERMEABILITY
• Degree of dye penetration will depend on the permeability or porosity of the
tissue.
• Highly permeable tissues are more easily stained and decolorized than
poorly permeable tissues.
22. METACHROMASIA
• A dye which has the ability to change its color without changing its chemical
structure is said to be metachromatic.
• The physical changes that bring about this color change are a specialized,
orderly form of dye aggregation.
23. • Toluidine blue - low conc- nucleus - blue
- high conc- cartilage - purple
http://ocw.tufts.edu/Content/15/coursehome/342521/342524/342548
Section of loose CT stained with
toluidine blue and demonstrating both
orthochromasia (bright blue color) and
metachromasia (dark purple color)
25. TYPES OF STAINING
A. PROGRESSIVE STAINING
• Tissue section is immersed in a dye bath until such time as only the desired
structures are stained.
• Difficult process to control
• E.g Mayer’s Haematoxylin: first stains the nuclei
26. B. REGRESSIVE STAINING
Tissues are over stained and the excess dye is removed until the desired tissue
component is selectively stained
• The dye is selectively removed from unwanted tissue groups – differentiation
• E.g In H/E staining, HCl is used as a differentiator
27. MORDANTS
• Term refers to a substance which acts as an intermediary between dye and tissue
• Advantage of dye mordent tissue complex is that it is virtually insoluble in most
fluids used in biological staining.
• Mordants are used in hematoxylins which makes it a strong basic dye, cationic
metal binding to both dye and tissue.
28. ACCENTUATORS
• Increase the selectivity or staining power of the dyes
• Effect of staining is due to change in pH of the staining solution
• Eg-potassium hydroxide in Loeffler’s methylene blue, phenol in carbon fusion.
• Accentuators when used in impregnation of nervous tissue with metallic salts is
called accelerators.
29. PARAFFIN SECTION
The basic steps in staining and mounting paraffin sections are as follows:
1. Deparaffinisation
2. Hydration
3. Staining
4. Dehydration
5. Clearing
6. Mounting
http://www.rajswasthya.nic.in/RHSDP%20Training%20Modules/Lab.%20Tech/Histo/Chapter%206.pdf
30. 1. DEPARAFFINISATION
• Removal of wax is done with xylene.
• At least 2 to 3 changes in xylene are given for about 3-5 mins to
remove the wax completely.
• Sections of this stage should appear clear and transparent.
31. 2. HYDRATION
• Most of the stains used are aqueous or dilute alcoholic solutions.
• The hydration is done with graded alcohol for higher concentration to lower
concentration.
• First change is made to absolute alcohol or acetone followed by 90,70% alcohol
and finally distilled water.
• Sections now should appear opaque.
• Presence of any clear areas are indicative of the presence of xylene.
• To remove this xylene, sections should be returned to absolute alcohol and
rehydrated.
32. 3. STAINING
• The most common stain applied for histological study is Haemotoxylin and Eosin.
• Various types of haemotoxylin formulations are used.
• Certain stains use strong chemicals e.g. ammonia. Sections tend to float off the
slides in such stains. This can be prevented by coating the selections by a thin layers
of celloidin (trimethylpyridine)
• For this sections are returned to absolute alcohol and then dipped in a dilute solution
of celloidin and finally hardened in 70% alcohol.
33. 5. DEHYDRATION AND CLEARING
• Dehydration is done is graded alcohols or acetones from 70% to absolute alcohol or
acetone.
• Dehydrating alcohol and acetones can remove some of the stains. Time has to be
suitably modified to minimize fading of stains.
• Since alcohol and acetone are miscible in xylol, it is used for clearing the sections.
• Any sections from which water has not been completely removed would give a milky
appearance after the first xylene.
• Such sections should be returned to absolute alcohol and the process should be repeated.
• Mounting is done after 2nd or 3rd xylene.
34. 6. COVERSLIPPING AND MOUNTING
Once the sections are clear. Do not let the section go dry before
mounting
1.Hold the slide between the thumb and the forefinger of one hand
and wipe with a clean cloth both ends of the slides. Look for the
engraved number to make sure the side the sections is present.
2.Clean carefully around the section and lay on a clean blotting paper
with section uppermost along with appropriate coverslip which has
already been polished.
35. 3. Place a drop of mountant on the slide over coverslip. Amount of mountant
should be just enough. Invert the slide over the coverslip and lower it so that it
just adheres to the cover slip , quickly turn the slide over and lay it on a flat
surface to allow the mountant to spread. Do not press or push the slide.
4. After the mountant has spread to the edge of the coverslip wipe around it for
neatness. If proper care has been taken there should be no air bubbles. If many
are present, slide should be returned to the xylol to remove the coverslip. It
will slip off and remounting is done. No attempt should be made to pull the
coverslip. Slight warming of the slide from below will make the small air
bubbles to escape from the slide of the coverslip.
5. Coverslip should be in the center of the slide with neatly written label on one
slide.
36. MOUNTANTS
Histological sections which need to be examined for any length of time or to be
stored, must be mounted under a cover-slip.
There are two types of mounting media :
1.Aqueous media - Used for material which is unstained, stained for fat, or
mechanically stained.
2.Resinous media - For routine staining.
37. A. AQUEOUS MEDIA
• These are used for mounting sections from distilled water when the stains
would be decolorised or removed by alcohol and xylene, as would be the
case with most of fat stains (Sudan methods). Gome stains,
• e.g. methyl violent, tend to diffuse into medium after mounting.
• Aqueous mounting require addition of bacteriostatic agents such as phenol,
crystal of thymol or sodium merthiolate to prevent the growth of fungi.
38. Permanent seal - After mounting the cover slip can be ringed by clear nail
polish for storage.
Following are some of the commonly used aqueous mounting media:
1. Apathy's medium (R.I- 1.52)
Medium for mounting sections for fluorescent microscopy.
2. Farrant's medium (R.I. 1.43)
Recommended for fat stains.
3. Glycerine jelly (R.I. 1.47)
Routine mountant for fat stains.
4. Highman's medium (R.I. 1.52)
Recommended with the metachroamtic dyes especially methyl violent.
39. B. RESINOUS MOUNTING MEDIA
Natural or synthetic resins dissolved in benzene, toluene or xylene. In case they become too
viscous they may have to be diluted with xylene.
Following are some of these media.
1. Canada balsam - Natural resin (R.I. - 1.52)
It is used as 60% resin by weight in xylene. H.&E stained slides are fairly well preserved
but basic aniline dyes tend to fade and prussian blue is slowly bleached. Slides take few
months to dry.
2.D.P.X. (R.I. 1.52)
Polystyrene resin dissolved in xylene as a 20% solution. It is most commonly used.
3.There are many other synthetic resins sold under various trade names e.g. Coverbond
(R.I. 1.53), H.S.R. (Harlew synthetic Resin), Histoclad (R.I. - 1.54), Permount (r.I. 1.54),
Pro-Texx (R.I. 1.495).
40. CRITERIA OF ACCEPTABLE MOUNTING MEDIA
1. Refractive index should be as close as possible to that of glass i.e. 1.5.
2. It should not cause stain to diffuse or fade.
3. It should be crack or appear granular on setting.
4. It should be dry to a nonsticky consistency and harden relatively quickly.
5. It should not shrink back from edge of cover-glass.
6. It should be free flowing and free bubbles.
41. TOLUIDINE BLUE STAINING:
Method:
Slide should be placed in 90% alcohol for a second or two
Transfer to absolute alcohol for a second or two
Transfer to xylene and agitate the slide until the section is clear ( about 2 Secs)
Transfer to absolute alcohol for a second or two
Transfer to 90% alcohol for a second or two
Transfer the slide rack, flood with 1% toluidine blue, and leave for about 1 Minute
Rinse rapidly in water, transfer to a pad of filter paper, and blot firmly
Flood with 90% alcohol and blot firlmy
Flood with absolute alcohol and blot firmly
Flood with xylene , blot firmly and , if the section is clear , mount under a coverslip with
balsam or DPX. If the section is not completely clear after the frst application of xylene .
Flood the slide with xylene and blot a second time, and repeat until the section is clear,
when it is mounted
42. REFERENCE:
1. Dyes and Pigments: Their Structure and Properties - Springer
2. https://www.scribd.com/doc/214111849/Staining-theory-pdf
3. http://www.rajswasthya.nic.in/RHSDP%20Training%20Modules/Lab.%20Tech/Histo/Chapter%206.pdf
4. https://monographs.iarc.fr/ENG/Monographs/vol99/mono99-7.pdf
5. http://www.biologydiscussion.com/micro-biology/staining/stains-meaning-purpose-and-components-
microorganisms/55080
6. Culling’s textbook – Staining and Impregnation
43. Describe why sections need to be coloured with dyes.
Staining is needed to give contrast between different components of the tissues and allow examination by light microscopy.
Describe how dyes bind to tissues.
Dyes bind by forming bonds with tissue components. Ionic and hydrogen bonding and van der Waals forces are probably all involved. Ionic staining
is the most important and distinguishes between basophilic and acidophilic tissue components. Hydrogen bonding and van der
Waals forces are less important but probably play a role in selectivity.
Describe the use of mordants in staining.
Mordants are metal salts that help bind some dyes to tissues . Haematoxylin is the most important mordanted dye.
Define metachromasia and give examples of its use.
Metachromasia produces a different colour in a tissue component to the colour of the dye solution. Toluidine blue is blue in solution but stains mast
cell granules red.
Describe the main properties of haematoxylin and staining using haematoxylin solutions.
Haematoxylin is a natural dye that requires oxidation to haematein before use as a stain. Haematoxylin is a mordanted dye that can stain many
different elements in tissue depending on the mordant used. Using different mordants it can be used to stain nuclei, connective tissue fibres, nerve
cells, muscle striations and mitochondria. It is usually used regressively.
Describe the use of silver as an impregnating metal.
Silver solutions are easily reduced producing a dense black deposit and this reduction is autocatalytic. In argentaffin reactions, no extra reducing
agent is needed, but argyrophil reactions require the addition of a reducing agent.
Describe the reasons for mounting tissues and outline the types of mounting media.
Mounting media and coverslips not only protect the specimen but also make it translucent, making examination easier. Mounting media may be
resinous (organic-based) or water-based solvents.
a. Staining enables to see the organism better in contrast with background.
b. differential stains being the Gram- stain and the acid-fast stain,
c. e.g spores, cell wall, nuclei (presence or absence of its cell wall)
natural dyes - histological purposes.
Haematoxylin i-heart wood of a tree (Haematoxylon campechianum),
carmine - cochineal female insect.
Synthetic dye: recombination of coal-tar products- eg. safranin, fast green, amiline blue, methylene blue, crystal violet, eosine, acid fuchsin, orange-G,
mordant dying processes(bond b/w metal ions & dyes).
(solvent-solvent)
(stain-stain)
picture
picture
Removal of wax with alcohol
Hydration through alcohol
Staining
Dehydration with alcohol
Clearing with xylene
Mounting with coverslip
Trimethylpyridine- Their chemical properties resemble those of pyridine, although the presence of the methyl groups will prohibit some of the more straightforward reactions.
Collidine comes in several isomers: 2,3,4-trimethylpyridine.
Miscible – (of liquids) forming a homogeneous mixture when added together.