Untitled - D Ank Unlimited

mesangial phagocytes 490 methotrexate (N-[p-{(2,4-diamino-6-pteridinyl
the reproductive system. It has been postulated to have a
carcinogenic effect. Mercury is allergenic, affects immunoglobulin
synthesis, and induces multispecific antibodies and
autoimmune reactions. Mercuric chloride serves as a polyclonal
activator of both B and T lymphocytes. Mercury’s
immunological effects are under genetic influence.
mesangial phagocytes
Renal macrophages.
metaproterenol (dl--[3,5-dihydroxyphenyl]-αisopropylamino-ethanol)
A β-adrenergic amine that induces smooth muscle relaxation,
especially in the bronchi, and is used to treat asthma.
metastases
Secondary tumors that arise from daughter cells released by
spread from a primary tumor to other anatomical sites.
metastasis
The transfer of disease from one organ or part to another
not directly connected with it. For example, malignant
tumors may seed anatomical sites distant from the site of
origin of the primary tumor, leading to the establishment of
secondary tumors.
metatype autoantibodies
Anti-immunoglobulin antibodies that recognize an antibody-liganded
active site but are not specific for the ligand
or idiotype alone. Metatype antibody interactions with
anti-metatype–metatype immunoglobulins serve as models
for T cell receptor and antigen–MHC complex interactions
that could be considered as metatype immunoglobulins and
liganded antibody, respectively.
Elie (Ilya) Metchnikoff.
Metchnikoff, Elie (1845–1916)
Elie (Ilya) Metchnikoff (also spelled Mechnikov) was born
in Avanovska, Ukraine. He showed an interest in natural
sciences from childhood and completed his 4-year university
studies in 2 years at the University of Kharkov, graduating
in 1864. He received a Ph.D. degree at the University
of Odessa. He studied with several researchers in Germany
and Italy and began publishing original observations at
H 2 N
N
N
NH 2
N
N
H C
H
CH 3
N
a young age. He returned to Russia in 1867 as professor
of zoology and comparative anatomy at the University of
Odessa. He was plagued with eye trouble and depression,
and lost his young wife to tuberculosis despite his devoted
efforts to save her life. His second marriage to a neighbor
was happy and the world is indebted to her for writing his
biography. Metchnikoff was not temperamentally suited
to teaching and left to pursue private studies in Messina.
He first studied phagocytes, examining the transparent
larvae of starfish. He observed that cells surrounded and
engulfed foreign particles introduced into the larvae. He
also discovered that special amoeba-like cells surrounded
bacteria introduced into starfish larvae and fungal spores
introduced into water fleas (Daphnia) and engulfed them.
He observed the digestive powers of the mesodermal
cells in starfish larvae and connected the process with the
cause of immunity against infectious disease. He returned
to Odessa and continued studies of parasite infection of
Daphnia, from which he built a theory of cellular immunity
involving phagocytosis. He was appointed director of the
Bacteriological Institute in Odessa. He was unhappy in that
position and visited the Hygiene Institute of Robert Koch,
who showed no interest in his research. When Metchnikoff
visited Pasteur in Paris, he was invited to remain, and
spent the rest of his life at Institut Pasteur. He found that
many white blood cells or leukocytes are phagocytic,
defending the body against acute infection by engulfing
invading microorganisms. After discovering the role of
phagocytes in host defense, he devoted much of his later
career to elaborating and championing his cellular theory of
immunity. He attracted a number of students including Jules
Bordet and published many papers, a series of Lectures on
the Comparative Pathology of Inflammation and a thorough
and balanced review of the entire field of comparative
and human immunity titled L’immunité dans les maladies
infectieuses. He was a colorful and influential personality.
He shared the Nobel Prize in Medicine or Physiology for
1908 with Paul Ehrlich for his work in immunology and
made many more contributions to immunity and bacteriology.
Metchnikoff became interested in longevity and aging
in his later years, and advocated the consumption of yogurt.
He believed that lactic acid-producing bacteria in the gut
prolonged life span.
methotrexate (N-[p-{(2,4-diamino-6-pteridinylmethyl)
methylamino} benzoyl] glutamic acid)
A drug that blocks synthesis of DNA and thymidine in
addition to its well known use as a chemotherapeutic agent
against neoplasia. It blocks dihydrofolate reductase, the
enzyme required for folic acid conversion to tetrahydrofolate.
Methotrexate has been used to treat cancer, psoriasis,
rheumatoid arthritis, polymyositis, Reiter’s syndrome, graftvs.-host
disease, and steroid-dependent bronchial asthma. It
inhibits both humoral and cell-mediated immune responses.
Its major toxicity is hepatic fibrosis, which is dose-related. It
may also produce hypersensitivity pneumonitis and
O
C
N
H
CH
Structure of methotrexate.
COOH
CH 2 CH 2
COOH