History
Introduction
Classification of grafts
The Immunology of Allogeneic Transplantation
Genetics of graft rejection
Types of rejection
Recognition of Alloantigens
Effector Mechanisms of Allograft Rejection
Prevention of graft rejection
Graft versus host reaction
History
Introduction
Classification of grafts
The Immunology of Allogeneic Transplantation
Genetics of graft rejection
Types of rejection
Recognition of Alloantigens
Effector Mechanisms of Allograft Rejection
Prevention of graft rejection
Graft versus host reaction
Hybridoma technology is a method for producing large number of identical antibodies called monoclonal antibodies.
It was discovered by G.kohler and C.milstein in 1975. they were awarded nobel prize for physiology and medicine in 1975.
The hybrid cells are produced by fusing B- lumphocyte with myeloma cells or tumour cells.
The B-lymphocyte have the ability to produce large number of antibodies and tumour cells have indefinite growth.
This is why two cells are used for the production of hybrid cell
The complement system is a part of the immune system that helps or complements the ability of antibodies and phagocytic cells to clear pathogens from an organism. It is part of the innate immune system, which is not adaptable and does not change over the course of an individual's lifetime.
consists of three pathways: 1. alternative
2. classical
3. lectin pathway
VIRAL VACCINES
Since viruses are intracellular parasites they will grow only within other living cells.
Methods of viral vaccine production:
Cultivation of virus using free living animals
Fertile eggs
Tissue cultures
Objective:
To create a superior enzymes to catalyze the production of high value specific chemicals.
To produce enzyme in large quantities.
Eliminate the need for co factor in enzymatic reaction.
Change substrate binding sites to increase specificity.
Change the thermal tolerance and pH stability.
Increase protein resistance to proteases.
To produce biological compounds.
Investigate how desired mutations can be introduced into a cloned gene
Hybridoma technology is a method for producing large number of identical antibodies called monoclonal antibodies.
It was discovered by G.kohler and C.milstein in 1975. they were awarded nobel prize for physiology and medicine in 1975.
The hybrid cells are produced by fusing B- lumphocyte with myeloma cells or tumour cells.
The B-lymphocyte have the ability to produce large number of antibodies and tumour cells have indefinite growth.
This is why two cells are used for the production of hybrid cell
The complement system is a part of the immune system that helps or complements the ability of antibodies and phagocytic cells to clear pathogens from an organism. It is part of the innate immune system, which is not adaptable and does not change over the course of an individual's lifetime.
consists of three pathways: 1. alternative
2. classical
3. lectin pathway
VIRAL VACCINES
Since viruses are intracellular parasites they will grow only within other living cells.
Methods of viral vaccine production:
Cultivation of virus using free living animals
Fertile eggs
Tissue cultures
Objective:
To create a superior enzymes to catalyze the production of high value specific chemicals.
To produce enzyme in large quantities.
Eliminate the need for co factor in enzymatic reaction.
Change substrate binding sites to increase specificity.
Change the thermal tolerance and pH stability.
Increase protein resistance to proteases.
To produce biological compounds.
Investigate how desired mutations can be introduced into a cloned gene
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
2. The importance of the immune system in protecting the body
against harmful foreign molecules is well recognized.
However, in some instances, this protection can result in serious
problems.
For example, the introduction of an allograft (that is, the graft of
an organ or tissue from one individual to another who is not
genetically identical) can elicit a damaging immune response,
causing rejection of the transplanted tissue.
Also, drugs are now available that more selectively inhibit
rejection of transplanted tissues while preventing the patient
from becoming immunologically compromised
Today, the principal approach to immunosuppressive therapy is
to alter lymphocyte function using drugs or antibodies against
immune proteins
3. Immunosuppressive therapy is also used in the
treatment of auto immune diseases
An immunomodulator is a substance(eg. a drug)
which has an effect on the immune system.
2 types
Immunosuppressants
Immunostimulants
6. Drugs may modulate immune mechanism by either
suppressing or by stimulating one or more of the following
steps:
Antigen recognition and phagocytosis
Lymphocyte proliferation/differentiation
Synthesis of antibodies
Ag –Ab interaction
Release of mediators due to immune response
Modification of target tissue response
7. The importance of immune system in protecting
the body against harmful molecules is well
recognized
However, in some instances, this protection can
result in serious problems
E.g, the introduction of allograft can elicit a
damaging immune response causing rejection of
the transplanted tissue
10. Cytokines are soluble, antigen-nonspecific, signaling proteins that bind to
cell surface receptors on a variety of cells.
The term cytokine includes the molecules known as interleukins (ILs),
interferons (IFNs), tumor necrosis factors (TNFs), transforming growth
factors, and colony-stimulating factors.
Of particular interest when discussing immunosuppressive drugs is IL-2, a
growth factor that stimulates the proliferation of antigen-primed (helper)
T cells, which subsequently produce more IL-2, IFN-γ, and TNF-α.
These cytokines collectively activate natural killer cells, macrophages,
and cytotoxic T lymphocytes. Clearly, drugs that interfere with the
production or activity of IL-2, such as cyclosporine, will significantly
dampen the immune response and, thereby, decrease graft rejection.
11. Cyclosporine is a lipophilic cyclic polypeptide composed of 11 amino
acids (several of the amino acids are methylated on the peptidyl
nitrogen).
The drug is extracted from the soil fungus Beauveria nivea.
Cyclosporine is used to prevent rejection of kidney,liver, and cardiac
allogeneic transplants.
Cyclosporine is most effective in preventing acute rejection of
transplanted organs when combined in a double-drug or triple-drug
regimen with corticosteroids and an antimetabolite such as
mycophenolate mofetil.
Cyclosporine is an alternative to methotrexate for the treatment of
severe, active rheumatoid arthritis.
It can also be used for patients with recalcitrant psoriasis that does not
respond to other therapies, and it is also used for xerophthalmia.
12. Cyclosporine preferentially suppresses cellmediated immune
reactions, whereas humoral immunity is affected to a far lesser
extent.
After diffusing into the T cell, cyclosporine binds to a cyclophilin
(more generally called an immunophilin) to form a complex that
binds to calcineurin.
The latter is responsible for dephosphorylating NFATc (cytosolic
Nuclear Factor of Activated T cells).
Because the cyclosporine-calcineurin complex cannot perform
this reaction, NFATc cannot enter the nucleus to promote the
reactions that are required for the synthesis of a number of
cytokines, including IL-2.
The end result is a decrease in IL-2,which is the primary chemical
stimulus for increasing the number of T lymphocytes.
13.
14. may be given either orally or by intravenous (IV) infusion. Oral absorption
is variable. Interpatient variability may be due to metabolism by a
cytochrome P450 (CYP3A4) in the gastrointestinal (GI) tract, where the
drug is metabolized.
Cyclosporine is also a substrate for P-glycoprotein (P-gp), a drug efflux
pump, which limits cyclosporine absorption by transporting the drug back
into the gut lumen. About 50 percent of the drug is associated with the
blood fraction. Half of this is in the erythrocytes,and less than one tenth
is bound to the lymphocytes.
Cyclosporine is extensively metabolized, primarily by hepatic CYP3A4.
[Note:
When other drug substrates for this enzyme are given concomitantly,
many drug interactions have been reported.]
It is not clear whether any of the 25 or more metabolites have any
activity. Excretion of the metabolites is through the biliary route, with
only a small fraction of the parent drug appearing in the urine.
15. Many of the adverse effects caused by cyclosporine are dose dependent.
Therefore, it is important to monitor blood levels of the drug.
Nephrotoxicity
[Note: Coadministration of drugs that also can cause kidney dysfunction
(for example, the aminoglycoside antibiotics) and anti-inflammatories,
such as diclofenac, naproxen, or sulindac, can potentiate the
nephrotoxicity of cyclosporine.
Lymphoma may occur in all transplanted patients due to the net level of
immunosuppression and has not been linked to any one particular agent.
Anaphylactic reactions can occur on parenteral administration.
Other toxicities include hypertension, gum hyperplasia ,hyperlipidemia,
hirsutism, hyperkalemia
16. Tacrolimus (originally called FK506) is a macrolide that is
isolated from the soil fungus Streptomyces tsukubaensis.
Tacrolimus is approved for the prevention of rejection of
liver and kidney transplants and is given with a
corticosteroid and/or an antimetabolite.
This drug has found favor over cyclosporine, not only
because of its potency and decreased episodes of
rejection, but also because lower doses of corticosteroids
can be used, thus reducing the likelihood of steroid-
associated adverse effects.
An ointment preparation has been approved for moderate
to severe atopic dermatitis that does not respond to
conventional therapies.
17. Tacrolimus exerts its immunosuppressive
effect in the same manner as cyclosporine,
except that it binds to a different
immunophilin, FKBP-12 (FK-binding
protein)(see diagram above).
18. Tacrolimus may be administered orally or IV.
The oral route is preferable, but, as with cyclosporine, oral absorption of
tacrolimus is incomplete and variable, requiring tailoring of doses.
Tacrolimus is subject to gut metabolism by CYP3A4/5 isoenzymes and is a substrate for P-gp.
Together, both of these mechanisms limit the oral bioavailability of tacrolimus.
Absorption is decreased if the drug is taken with high-fat or high-carbohydrate meals. Tacrolimus
is from 10- to 100-fold more potent than cyclosporine.
It is highly bound to serum proteins and is also concentrated in erythrocytes.
Like cyclosporine, tacrolimus undergoes hepatic metabolism by the CYP3A4/5 isozyme, and the
same drug interactions occur.
At least one metabolite of tacrolimus has been shown to have immunosuppressive activity.
Renal excretion is very low, and most of the drug and its metabolites are found in the feces.
19. Nephrotoxicity and neurotoxicity (tremor, seizures, and
hallucinations) tend to be more severe in patients who are
treated with tacrolimus than in patients treated with
cyclosporine, but careful dose adjustment can minimize this
problem.
Development posttransplant, insulin-dependent diabetes mellitus
is a problem, especially in black and Hispanic patients.
Other toxicities are the same as those for cyclosporine, except
that tacrolimus does not cause hirsutism or gingival hyperplasia.
Compared with cyclosporine, tacrolimus has also been found to
have a lower incidence of cardiovascular toxicities, such as
hypertension and hyperlipidemia, both of which are common
disease states found in kidney transplant recipients.
Anaphylactoid reactions to the injection vehicle have been
reported. The drug interactions are the same as those described
for cyclosporine
20. Sirolimus is a macrolide obtained from fermentations
of the soil mold Streptomyces hygroscopicus.
The earlier name, and one that is sometimes still
used, is rapamycin.
Sirolimus is approved for use in renal transplantation,
to be used together with cyclosporine and
corticosteroids, llowing lower doses of those
medications to be used, thereby lowering their toxic
potential.
The combination of sirolimus and cyclosporine is
apparently synergistic because sirolimus works later
in the immune activation cascade.
21. Sirolimus and tacrolimus bind to
the same cytoplasmic FK-binding
protein, but instead of forming a
complex with calcineurin, sirolimus
binds to mTOR, interfering with
Signal3.
Binding of sirolimus to mTOR blocks
the progression of activated
T cells from the G1 to the S phase
of the cell cycle and.
Consequently, the proliferation of
these Unlike cyclosporine and
tacrolimus, sirolimus does not owe
its effect to lowering IL-2
production but, rather, to
inhibiting the cellular responses to
IL-2.
22. The drug is available only as oral preparations and has similar adverse
effects as Tacrolimus, so is the other drug Everolimus .
Although it is readily absorbed, high-fat meals can decrease the
drug’s absorption.
Sirolimus has a long half-life (57 to 62 hours) compared to those of
cyclosporine and tacrolimus, and a loading dose is recommended at the
time of initiation of therapy, but only requires once daily dosing.
Like both cyclosporine and tacrolimus, sirolimus is metabolized by the
CYP3A4 isozyme and interacts with the same drugs as do cyclosporine and
tacrolimus.
Sirolimus also increases the drug concentrations of cyclosporine, and
careful blood level monitoring of both agents must be done to avoid
harmful drug toxicities.
The parent drug and its metabolites are predominantly eliminated in
feces.
23. Immunosuppressive antimetabolite agents
are generally used in combination with
corticosteroids and the calcineurin inhibitors,
cyclosporine and tacrolimus.
24. Azathioprine was the first agent to achieve wide spread use in organ
transplantation.
It is a prodrug that is converted first to 6-mercaptopurine (6-MP) and then to the
corresponding nucleotide, thioinosinic acid.
The immunosuppressive effects of azathioprine are due to this nucleotide analog.
Because of their rapid proliferation in the immune response and their dependence
on the de novo synthesis of purines required for cell division, lymphocytes are
predominantly affected by the cytotoxic effects of azathioprine.
[Note: The drug has little effect on suppressing a chronic immune response.]
Its major nonimmune toxicity is bone marrow suppression. Concomitant use with
angiotensin-converting enzyme inhibitors or cotrimoxazole in renal transplant
patients can lead to an exaggerated leukopenic response. Allopurinol, an agent used
to treat gout, significantly inhib-
its the metabolism of azathioprine.
Therefore, the dose of azathioprine must be reduced by 60 to 75 percent.
25. Mycophenolate mofetil/ Enteric-coated mycophenolate
sodium has, for the most part, replaced azathioprine
because of its safety and efficacy in prolonging graft
survival.
It has been successfully used in heart, kidney, and liver
transplants.
This is a potent, reversible, uncompetitive inhibitor of
inosine monophosphate dehydrogenase, which blocks the
de novo formation of guanosine phosphate. Thus, like 6-
MP, it deprives the rapidly proliferating T and B cells of a
key component of nucleic acids
The most common adverse eff ects include diarrhea,
nausea, vomiting, abdominal pain, leukopenia, and anemia
26. The use of antibodies plays a central role in
prolonging allograft survival.
They are prepared either by immunization of
rabbits or horses with human lymphoid cells
(producing a mixture of polyclonal antibodies
directed against a number of lymphocyte
antigens), or by hybridoma technology producing
antigen-specific, monoclonal antibodies).
[Note: Hybridomas are produced by fusing mouse
antibody-producing cells with
immortal,malignant plasma cells
27. (Hybrid cells are selected and cloned) and the
antibody specificity of the clones is
determined.
Clones of interest can be cultured in large
quantities to produce clinically useful
amounts of the desired antibody.
Recombinant DNA technology can also be used
to replace part of the mouse gene sequence
with human genetic material, thus
“humanizing” the anti bodies produced,
making them less antigenic.
The names of monoclonal antibodies
conventionally contain “muro” if they
are from a murine (mouse) source and “xi” or
“zu” if they are chimerized or
humanized, respectively.
The suffix “mab” (monoclonal antibody)
identifies the category of drug.
The polyclonal antibodies, although relatively
inexpensive to produce, are variable and less
specific, which is in contrast to monoclonal
antibodies, which are homogeneous and
specific.
28.
29. Thymocytes are cells that develop in the thymus and serve
as T-cell precursors.
The antibodies developed against them are prepared by
immunization of large rabbits or horses with human
lymphoid cells and, thus,are polyclonal.
They are primarily used, together with other immuno
suppressive agents, at the time of transplantation to
prevent early allograft rejection, or they may be used to
treat severe rejection episodes or corticosteroid-resistant
acute rejection.
Rabbit formulations of polyclonal antithymocyte globulin
are more commonly used over the horse preparation due
to greater potency.
30. The antibodies bind to the surface of circulating T lymphocytes, which
then undergo various reactions, such as complement-mediated
destruction, antibody-dependent cytotoxicity, apoptosis, and psonization.
The antibody-bound cells are phagocytosed in the liver and spleen,
resulting in lymphopenia and impaired T-cell responses.
The antibodies are slowly infused intravenously, and their half-life
extends from 3 to 9 days.
Because the humoral antibody mechanism remains active, antibodies can
be formed against these foreign proteins.
[Note: This is less of a problem with the humanized antibodies.]
Other adverse effects include chills and fever, leukopenia and
thrombocytopenia, infections due to CMV or other viruses,and skin
rashes.
31. Muromonab-CD3 is a murine monoclonal antibody that is synthesized by hybridoma
technology and directed against the glycoprotein CD3 antigen of human T cells.
Muromo nab CD3 is used for treatment of acute rejection of renal allografts as well
as for corticosteroid-resistant acute allograft rejection in cardiac and hepatic
transplant patients.
It is also used to deplete T cells from donor bone marrow prior to transplantation.
Mechanism of action:
Binding to the CD3 protein results in a disruption of T-lymphocyte function, because
access of antigen to the recognition site is blocked.
Circulating T cells are depleted, thereby decreasing their participation in the
immune response.
Because muromonab-CD3 recognizes only one antigenic site, the
immunosuppression is less broad than that seen with the polyclonal antibodies.
T cells usually return to normal within 48 hours of discontinuation of therapy.
32. The antibody is administered IV. Initial
binding of muromonab-CD3 to the antigen
transiently activates the T cell and results in
cytokine release (cytokine storm ).
It is, therefore, customary to premedicate
the patient with methylprednisolone, diphen-
hydramine, and acetaminophen to alleviate
the cytokine-release syndrome.
33. Anaphylactoid reactions may occur.
Cytokine release syndrome .
Flu-like illness to a life-threatening, shock-like reaction.
High fever is common.
Central nervous system effects, such as seizures, encephalopathy,
cerebral edema, aseptic meningitis, and headachemay occur.
Infections can increase, including some due to CMV.
Muromonab-CD3 is contraindicated in patients with a history of seizures,
in those with uncompensated heart failure, in pregnant women etc.
34. The antigenicity and short serum half-life of the murine
monoclonal
antibody have been averted by replacing most of the murine
amino
acid sequences with human ones by genetic engineering.
Basiliximab is said to be “chimerized” because it consists of 25
percent murine and 75 percent human protein.
Daclizumab is 90 percent human protein, and is designated
“humanized.”
Both agents have been approved for prophylaxis of acute
rejection in renal transplantation in combination with
cyclosporine and corticosteroids. They are not used for the
treatment of ongoing rejection
35. Both compounds (daclizumab, Basiliximab) are
anti-CD25 antibodies and bind to the α chain of
the IL-2 receptor on activated T cells.
They thus interfere with the proliferation of
these cells. Basiliximab is about 10-fold more
potent than daclizumab as a blocker of IL-2
stimulated T-cell replication.
Blockade of this receptor foils the ability of any
antigenic stimulus to activate the T-cell response
system.
36. Both antibodies are given IV. The serum half-life
of daclizumab is about 20 days, and the blockade of
the receptor is 120 days.
Five doses of daclizumab are usually administered,
the first at 24 hours before transplantation, and the
next four doses at 14-day intervals.
The serum half-life of basiliximab is about 7 days.
Usually, two doses of this drug are administered, the
first at 2 hours prior to transplantation, and the
second at 4 days after the surgery.
37. Both daclizumab and basiliximab are well
tolerated.
Their major toxicity is GI.
No clinically relevant antibodies to the drugs
have been detected, and malignancy does
not appear to be a problem.
38. Alemtuzumab a humanized monoclonal antibody directed against
CD52, exerts its effects by causing profound depletion of T cells
from the peripheral circulation.
This effect may last for up to 1 year.
Alemtuzumab is currently approved for the treatment of
refractory B-cell chronic lymphocytic leukemia.
Although it is not currently approved for use in organ
transplantation, it is being used in combination with sirolimus
and low-dose calcineurin inhibitors in corticosteroid-avoidance
protocols at many transplant centers.
Preliminary results are promising, with low rates of rejection
with a prednisone-free regimen. Side effects include first-dose
cytokine-release syndrome, neutropenia, anemia.
41. The corticosteroids were the first pharmacologic agents to be used as
immunosuppressives both in transplantation and in various autoimmune
disorders.
They are still one of the mainstays for attenuating rejection episodes.
For transplantation, the most common agents are prednisone or
methylprednisolone, whereas prednisone or prednisolone are used for
autoimmune conditions.
[Note: In transplantation, they are used in combination with agents
described previously in this lecture]
The steroids are used to suppress acute rejection of solid organ
allografts and in chronic graft-versus-host disease.
In addition, they are effective against a wide variety of autoimmune
conditions, including refractory rheumatoid arthritis, systemic lupus
erythematosus, temporal arthritis, and asthma.
42. Mechanism of Action:
The mechanism of action responsible for the immunosuppressive action of the
corticosteroids is unclear some academic thoughts suggest the drug binds to DNA
and bound receptor then interacts with basic transcription factors, causing an
increase or decrease in expression of specific target genes, including suppression of
IL2 (interleukin 2) expression. The T lymphocytes are affected most.
The steroids are able to rapidly reduce lymphocyte populations by lysis or
redistribution. On entering cells, they bind to the glucocorticoid receptor.
The complex passes into the nucleus and regulates the translation of DNA. Among
the genes affected are those involved in inflammatory responses.
The use of these agents is associated with numerous adverse effects.
For example, they are diabetogenic and can cause hypercholesterolemia, cataracts,
osteoporosis, and hypertension with prolonged use. Consequently, efforts are being
directed toward reducing or eliminating the use of steroids in the maintenance of
allografts.
43. Created by Pharmacologist L. Mweetwa for:
Pharmacy, Medical Students and Other
Interested Health Care Students
Disclaimer:
These slides have been created for educational purposes only, the author does not, in any way,
profit from it and that all rights regarding information ,images, characters used in this
presentation belong to their original creator(s)
More slides on other topics available on request
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