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Biomedical subjects

M Schwartz

Publications and source records attributed to M Schwartz.

At least 685 records · Page 38Linked to original sources
PubMed1982

A serine protease activity of human serum albumin towards 4-methylumbelliferyl-guanidinobenzoate (MUGB) and diisopropyl fluorophosphate (DEP): implications for the use of MUGB reactivity in amniotic fluid in prenatal diagnosis of cystic fibrosis.

4-methylumbelliferylguanidinobenzoate (MUGB) reactivity in plasma from patients with cystic fibrosis and in amniotic fluid from pregnancies leading to children with cystic fibrosis, has been reported to be significantly decreased. We have so far been unable to confirm these findings and have therefore reexamined this reactivity using diisopropylfluorophosphate (DEF), another active site titrant of serine proteases. We have shown that MUGB and DFP are reacting with the same molecules in plasma and amniotic fluid. Using crossed immunoelectrophoresis and SDS-polyacrylamide gel electrophoresis of 3H-DFP labelled plasma and amniotic fluid we have obtained strong evidence that the main contribution of MUGB and DFP reactive protein in plasma and amniotic fluid is identical to serum albumin. The use of MUGB reactivity in amniotic fluid in pregnancies at risk for cystic fibrosis must therefore be reconsidered.

Amniotic Fluid↗
PubMed1982

Monoclonal antibody as a probe for structure and function of an Escherichia coli outer membrane protein.

Eight independently derived monoclonal antibodies directed against the LamB protein were produced and characterized. By using these antibodies as probes, we identified four distinct topological and functional regions in the LamB molecule. Four monoclonal antibodies recognize antigenic determinants of the protein exposed on the outer side of the membrane. Two of these have their binding sites located in a region involved in maltose transport. One monoclonal antibody presumably binds to a determinant which is normally hidden in the membrane and three monoclonal antibodies recognize determinants facing the periplasmic space.

Animals↗
PubMed1982

Regenerating goldfish retinal explants: induction and maintenance of neurites by conditioned medium from cells originated in the nervous system.

Fiber outgrowth from goldfish regenerating retinas can be induced by conditioned medium of cloned cells which originated in the nervous system, i.e. glioma and neuroblastoma. Dilution of the released factor(s) was required to achieve optimal effect; high concentrations are detrimental. The fibers can be maintained for at least 2 weeks in vitro, and reach a length of several millimeters. This system may provide a means to purify and characterize neurotrophic factors involved in nerve regeneration.

Animals↗
PubMed1982

Factor(s) from goldfish brain induce neuritic outgrowth from explanted regenerating retinas.

The extensive outgrowth from explanted goldfish retina in vitro stimulated by the axotomy of the optic nerve several days prior to the explantation, enables a more direct examination of the events which accompany optic nerve regeneration. Thus far neuritic outgrowth has been obtained in serum-containing medium. In the present report we demonstrate for the first time that factor(s) from adult goldfish brain can support neuritic outgrowth from retinal explant and replace the serum. This finding suggests that goldfish neuronotrophic factor(s) are active on retinal ganglia cells. Under the same experimental conditions nerve growth factor from submaxillary gland did not exhibit outgrowth stimulatory activity.

Animals↗
PubMed1982

Successful treatment of far-advanced progressive systemic sclerosis by D-penicillamine.

A 52-yr-old man had chronic recurrent pseudo-obstruction of the colon, along with multisystem disease secondary to progressive systemic sclerosis (PSS). D-Penicillamine treatment reversed the PSS, which involved the duodenum, small and large intestines, lungs, myocardium, and proximal and peripheral skin. The improvement was documented by electrocardiogram pulmonary function studies, roentgenography of gastrointestinal tract, and by repeated skin biopsies. Hand blood-volume studies using 99m Tc also revealed improvement of PSS in both hands. A variable degree of improvement was documented in seven additional patients with PSS. Follow-up periods were 18 mo to 4 yr. The most common side effect of the drug was transient hypogeusia, and no patient showed a serious side effect. This article includes a review of the literature on penicillamine therapy for PSS.

Adolescent↗
PubMed1982

Sprouting from chicken embryo dorsal root ganglia induced by nerve growth factor is specifically inhibited by affinity-purified antiganglioside antibodies.

The involvement of gangliosides in processes related to nerve regeneration and sprouting has been demonstrated recently. The type of interaction by which gangliosides may influence neuronal sprouting was investigated in the present work. Affinity-purified rabbit anti-GM1 antibodies were found to block the sprouting from dorsal root ganglia (DRG) of chicken embryo induced by nerve growth factor (NGF). Only a moderately inhibitory effect was produced by antibodies directed to GM2, suggesting a specific interaction between NGF and GM1. In spite of the low inhibitory effect of anti-GM2 antibodies on sprouting, their binding to dissociated DRG cells was found to be higher than that of anti-GM1 antibodies. These results emphasize the high resolution of the system and suggest that the interaction of NGF with GM1 is involved in the process of sprouting.

Animals↗
PubMed1982

Continuing medical education in New York County: physician attitudes and practices.

New York County physicians were surveyed by questionnaire concerning their attitudes and practices regarding continuing medical education (CME). There were 1,558 responders, and they included those practicing in shared health facilities (SHF) and random samples of academicians on the faculties of the four medical schools and of the entire physician population of Manhattan. Reading professional books and journals was regarded as by far the most important CME activity by all three groups of physicians, and this activity consumed about four hours per week. All physicians spent several days and often as much as two weeks per year attending professional meetings and formal postgraduate courses. The former were rated as not very useful and the latter as quite useful for CME. Major impediments to CME participation for all groups were time away from home and practice, expense, loss of income, and scheduling problems. Relevance, quality, and organization of CME courses were not major impediments. SHF physicians differed little from other physicians in their attitudes, perceptions, and practices concerning CME.

Attitude of Health Personnel↗
PubMed1982

Antiganglioside antibodies inhibit neuritic outgrowth from regenerating goldfish retinal explants.

Antibodies elicited in rabbits against bovine brain gangliosides were applied to regenerating retinal explants to examine the role of gangliosides in the trophic effect responsible for the induction of outgrowth. The results indicate that antibodies specific to gangliosides block the neuritic outgrowth from the regenerating retinal explants. It is inferred that gangliosides function as receptors on the cell surface of the retinal explants that interact with the trophic substances inducing the outgrowth. The relevance of gangliosides to the mechanism of regeneration and development induced by trophic factors is discussed.

Animals↗
PubMed1982

Abnofmalities in brain myelin or rabbits with experimental autoimmune multiple sclerosis-like disease induced by immunization to gangliosides.

An experimental autoimmune multiple sclerosis-like disease (EAMSD) was induced in rabbits by immunizing them with bovine brain gangliosides. Forebrain myelin was isolated and fractionated on a discontinuous sucrose gradient into light myelin (LM, buoyant density less than or equal to 0.625 M), and heavy myelin (HM, buoyant density greater than 0.625 M). No abnormalities in either protein or lipid composition of EAMSD myelin fractions were observed. However, the EAMSD tissue yielded 31% less light and 39% more heavy myelin compared to the control brains. Thus, the HL/LM ratio was two-fold greater in experimental than in control myelin. This pathological pattern is similar to that which has been observed in myelin obtained from the brains of multiple sclerosis patients and from the optic nerves of rabbits with experimentally-induced demyelination.

Animals↗