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Biomedical subjects

J Smith

Publications and source records attributed to J Smith.

At least 1,117 records · Page 62Linked to original sources
PubMed1985

Antiserum to lens antigens immunostains Müller glia cells in the neural retina.

Antiserum to a lens fraction enriched for alpha-crystallin selectively immunostains Müller glia cells in the neural retina of several vertebrate species. Also, in embryonic retina (chicken), this antiserum reacts with Müller cells and, at early stages of development, with their apparent precursors. Thus, antibodies to a lens product(s) detect a Müller glia cell marker that begins to be expressed very early in their ontogeny and can be useful in studies on differentiation, function, and pathologies of this cell type.

Animals↗
PubMed1985

Differentiation of catecholaminergic cells in cultures of embryonic avian sensory ganglia.

From the results of previous studies in which developing peripheral ganglia from quail embryos were transplanted into younger chicken embryo hosts, we concluded that spinal and cranial sensory ganglia contain dormant precursors with autonomic potentialities. Here we describe the differentiation of these precursors in vitro, from dorsal root and nodose ganglion cell suspensions. Dorsal root ganglia were removed from quail embryos at 9 to 15 days of incubation, dissociated to single cells, and grown in tissue culture. The differentiation of cells with autonomic features was followed by monitoring properties associated with the adrenergic phenotype (absent from quail sensory ganglia during normal embryonic development). Provided that the medium was supplemented with chicken embryo extract, numerous cells displaying tyrosine hydroxylase immunoreactivity could be detected from day 4 onward. They possessed long, multiple processes but appeared morphologically distinct from primary sensory neurons. The catalytic activity of tyrosine hydroxylase and of other enzymes required for catecholamine production was demonstrated in the cultures by glyoxylic acid-induced histofluorescence and by radiochemical measurement of the conversion of exogenous tyrosine to norepinephrine. A large proportion of tyrosine hydroxylase-positive cells were found to incorporate [3H]thymidine before and after differentiating. In contrast, recognizable sensory neurons never exhibited adrenergic properties and did not divide. Qualitatively similar results were obtained with cultures of dissociated nodose ganglia. These findings lend further weight to the assumption that latent autonomic precursors are included in the non-neuronal compartment of sensory ganglia.

Adrenergic Fibers↗
PubMed1985

Bursa formation in secondary chondrosarcoma with intrabursal chondrosarcomatosis.

Osteocartilaginous exostoses (osteochondromata) are rather common bone tumors. Although most are straightforward lesions, one may occasionally encounter one of a number of well-recognized complications. In the current case, secondary malignant transformation and bursal sac formation were present. Additionally, numerous malignant chondroid nodules were shed into the attached bursa, giving rise to a large soft tissue mass, a situation which we feel is both remarkable and, to our knowledge, unique.

Aged↗
PubMed1985

Heterogeneity of Trichomonas vaginalis and discrimination among trichomonal isolates and subpopulations with sera of patients and experimentally infected mice.

The antibody response in trichomoniasis patients was examined with a variety of methodologies including enzyme-linked immunosorbent assays, indirect immunofluorescence, immunoblotting, and radioimmunoprecipitation-electrophoresis-autoradiography. Based on enzyme-linked immunosorbent assay recognition of trichomonal isolates, sera from patients with trichomoniasis were categorized into reactive class I (IA, IB, and IC) and nonreactive class II sera. A diminished ability to precipitate antibody-binding trichomonad membrane proteins by the whole cell radioimmunoprecipitation assay was noted from class IA to class II sera. The antigenic distinctions among various Trichomonas vaginalis isolates appeared due to high-molecular-weight protein antigens detected by class IA sera in a whole cell radioimmunoprecipitation assay. The heterogeneity in antigenic patterns was confirmed among the isolates with sera from experimental animals. Also, live T. vaginalis cells appear to have only a few of the entire repertoire of major immunogenic surface proteins accessible to antibody binding. Immunoblotting demonstrated that the high-molecular-weight proteins responsible for trichomonal isolate heterogeneity are present in all isolates. The data suggest that trichomonads of a given isolate express only a subset of internally synthesized protein antigens on their surface. Importantly, the presence of these protein antigens on T. vaginalis membranes correlated with antibody production in subcutaneously challenged mice. Finally, indirect immunofluorescence studies with highly reactive, pooled sera from either patients or mice revealed a subpopulation of nonstaining trichomonads. These data support the view that heterogeneity among T. vaginalis is dependent upon the surface disposition of highly immunogenic protein antigens. Strategies may now be developed not only for studying potential vaccine reagents, but also for examining possible antigenic phenotypic variations in this experimental model.

Agglutination↗
PubMed1985

Determining the use of physical assessment skills in the clinical setting.

This study examined the clinical application of physical assessment skills by baccalaureate nurses. Fifty-nine pediatric staff nurses practicing in two different hospitals in Southern California completed a questionnaire which surveyed how frequently assessment skills were utilized and what deterrents, if any, inhibit their use. Approximately one-third of the 36 skills listed were utilized daily by at least 74% of the participants, and respondents selected a variety of deterrents to the utilization of other skills. There was no significant difference in the utilization of skills between nurses who had taken a separate course in physical assessment and those from an integrated curriculum.

California↗
PubMed1985

Converting enzyme inhibition resets cerebral autoregulation at lower blood pressure.

The cerebrovascular effect of converting enzyme inhibition was investigated in normal volunteers, in hypertensive patients and in patients with severe chronic heart failure. Cerebral blood flow (CBF) was measured by single photon emission tomography of the uptake and wash-out of inhaled xenon-133. In some of the patients, CBF was also monitored by repeated determinations of the cerebral arterio-venous oxygen difference. In the normal volunteers and the hypertensive patients captopril (50 mg) caused a downward shift of the lower limit of CBF autoregulation of 10-15 mmHg. In some of the patients with chronic heart failure, captopril (6.25 mg) induced a marked decrease of the arterial blood pressure. Regional and average CBF, however, remained constant. These findings indicate that captopril treatment may protect the brain against ischaemia during sudden decreases of the blood pressure by a shift of the lower limit of CBF autoregulation.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

[Expression of the adrenergic phenotype by dorsal root ganglion cells of the quail in culture in vitro].

From the results of previous studies, we have suggested that "autonomic" cell precursors exist in latent form in sensory ganglia of avian embryos. The potentialities can be expressed when the ganglia are transplanted into a young embryo host. In the present study, we have observed a similar transformation in cultures of dissociated dorsal root ganglia taken from quail embryos of 7-15 days of incubation. From the 4th day of culture onward, numerous adrenergic cells appear. They display tyrosine hydroxylase immunoreactivity, synthesise and store catecholamines and generally differ in size and shape from primary sensory neurons. They and/or their precursors can actively proliferate in culture. The differentiation of these catecholaminergic cells, which can not be detected in quail dorsal root ganglia during normal development in vivo, is dependent on one or more factors present in 9-day chick embryo extract.

Animals↗
PubMed1985

Single cell analysis of commitment in early embryogenesis.

Fate maps of amphibian embryos tell us the destination of certain areas at later stages of development. After studying Vogt's fate maps, Spemann wrote (in 1938) that "the question which at once calls for an answer is whether this pattern of presumptive primordia in the beginning gastrula is the expression of a real difference of these parts, whether they are already more or less predestined or 'determined' for their ultimate fate, or whether they are still indifferent and will not receive their determination until a later time." Until recently answers to this question have relied upon explant experiments, which indicate that by the late blastula stage ectoderm, mesoderm and endoderm regions are distinctly determined. By using a method involving single cell labelling and transplantation, it is now possible to pinpoint more accurately the time during early embryogenesis at which individual blastomeres become committed. In the vegetal pole, determination towards endoderm is a gradual process beginning during the middle blastula stage (stage 8) and completed by the beginning of gastulation (stage 10). This method offers the possibilities of comparing the committed and the uncommitted state and studying at a molecular level the mechanisms of cell determination.

Amphibians↗
PubMed1985

In vivo and in vitro studies on the segregation of autonomic and sensory cell lineages.

Analysis of interspecific quail/chick chimaeras (made by grafting neural primordium from one species to the other) has demonstrated that the neural crest cell population, which gives rises to a large number of derivatives, including the great majority of peripheral ganglion cells, is pluripotential. When peripheral ganglia themselves are transplanted, it can be shown that many of the developmental potentialities of the parent structure are retained, their ultimate expression depending on the microenvironment in which they become located. One of the conclusions obtained from these in vivo studies, that sensory ganglia contain dormant precursors with autonomic potentialities, has been confirmed and extended by the results of in vitro investigations with dissociated 9- to 15-day embryonic quail dorsal root ganglia. Undetectable during normal embryonic development, adrenergic properties (tyrosine hydroxylase immunoreactivity, radio- and cytochemically demonstrable catecholamine production) develop in a population of small, multipolar cells after four days in culture. This differentiation is strongly dependent on the presence of chick embryo extract in the medium. Unlike the postmitotic primary sensory neurons of the ganglia, many of the adrenergic cells were found to incorporate 3H-thymidine during the culture period. These results support the contention that the latent autonomic percursors belong to the non-neuronal compartment of sensory ganglia.

Adrenergic Fibers↗
PubMed1985

Blood leucocyte infiltration after intravenous injection of ferritin in the rat.

Monocytes infiltrate glomeruli during mesangial deposition of ferritin, and during experimental glomerulonephritis. To determine whether this is solely a local phenomenon, leucocyte infiltration in other organs has been studied following intravenous ferritin injection. Lewis rats received an i.v. injection of 150 mg ferritin/100 g body weight. At 24 h there was a peripheral blood leucocytosis (ferritin-treated rats 26.32 +/- 13.7, control rats 8.54 +/- 2.41 X 10(6) cells/ml) due to increase in polymorphs and monocytes. Bone marrow cell counts fell (ferritin-treated rats 49 +/- 7, control 80 +/- 11 X 10(6)/100 g body weight). Cell counts on cell suspensions of perfused, enzyme-digested lung, liver and spleen, and lung lavage showed major significant increases in total cell counts: lung 250 +/- 36 (89 +/- 16), lung lavage 2.6 +/- 0.8 (1.4 +/- 0.5), liver 140 +/- 37 (60 +/- 11), spleen 306 +/- 38 (200 +/- 27) X 10(6)/100 g body weight (control values in parentheses). Cytospin preparations of these suspensions, stained for non-specific esterase showed that the increase in cell numbers was due to increases in non-specific esterase-positive cells (monocytes) and polymorphs. These results demonstrate a generalized leucocyte mobilization, sequestration, and tissue infiltration after i.v. ferritin. The renal glomerulus therefore is not the only site of leucocyte accumulation. These findings may have relevance for studies on inflammation mediated by leucocytes in models of experimental immune complex glomerulonephritis.

Animals↗
PubMed1985

[Characterization of strains of Escherichia coli isolated from calves with neonatal diarrhea].

Thirty fecal samples of diarrheic calves from a beef herd with previous history of neonatal diarrhea were cultured for isolation of Escherichia coli K99 (+) and for enterotoxigenic tests. The age distribution of sampled calves was: 1 animal less than 6 days old, 21 between 7-15 days old and 8 between 16-30 days old. Although most strains were classified as Isaacson et al (16) biotype four, they were negative for detection of K99 antigen by slide agglutination test. The assay for heat-stable (ST) and heat-labile (LT) enterotoxins by intragastric infant mouse inoculation and ELISA tests, respectively, were negative. More than 93% of the E. coli strains were sensitive to ampicillin, colistin, gentamycin and nitrofurantoin .

Animals↗
PubMed1985

Impact of an intermittent catheterization program on children with myelomeningocele.

Among 164 children being followed in a myelomeningocele clinic, 85 (52%) are on an intermittent catheterization program (ICP). Among 53 children on ICP for 5 years or more, a high percentage have achieved satisfactory dryness, decreased frequency of urinary tract infection, and improvement in renal status. The potential for improved well-being afforded by ICP is one factor that should be considered in decisions about "active" or "supportive" treatment in newborn infants with myelomeningocele.

Child↗