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Biomedical subjects

A Hunter

Publications and source records attributed to A Hunter.

At least 109 records · Page 6Linked to original sources
PubMed1989

Ambiguous genitalia associated with skeletal abnormalities, cutis laxa, craniostenosis, psychomotor retardation, and facial abnormalities (SCARF syndrome).

We describe 2 male maternal first cousins, 7 years and 7 months old, with a previously unreported pattern of malformations including lax skin, joint hyperextensibility, umbilical and inguinal herniae, craniosynostosis, pectus carinatum, several abnormally shaped vertebrae, enamel hypoplasia and hypocalcification of the teeth, facial abnormalities and wide webbed neck, ambiguous genitalia, multiple nodular liver tumors, and mild psychomotor retardation. The occurrence of 2 male children related through their mothers suggests the possibility of X-linked recessive inheritance. It is proposed to call this disorder the SCARF syndrome (skeletal abnormalities, cutis laxa, craniostenosis, ambiguous genitalia, retardation, facial abnormalities).

Abnormalities, Multiple↗
PubMed1989

Education to meet the challenge of AIDS.

Studies of health care providers' attitudes have revealed that many have misconceptions and fears about AIDS and possess negative attitudes about caring for people with the disease. Merely transmitting the basic facts about AIDS is insufficient to prepare health care workers to deal with AIDS patients. This article discusses the need for continuing education for health care professionals and educators and offers a model for the development of educational programs. The model is being developed in the School of Allied Health Professions, State University of New York at Stony Brook. Principles of "andragogy"--involvement of both the learner and the educator in identifying students' needs, planning learning experiences, and ongoing evaluation of the learning process--are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1989

A quantitative analysis of the synaptic development of the lobus parolfactorius of the chick (Gallus domesticus).

The lobus parolfactorius (LPO) of the chick has been shown to undergo an increase in the mean synaptic numerical density (Nvsyn) in response to one-trial passive avoidance learning (Stewart et al. 1987). The present study was undertaken in order to describe the pattern of normal development of synapses in the LPO, to further investigate the significance of this plastic response. The LPO's from each hemisphere of pre-hatch (16 days), and post-hatch (1 day, 9 day and 22 day old) chicks were processed for electron microscopy. Synapses were classified into asymmetric spine, asymmetric shaft, symmetric spine, and symmetric shaft synapses, on the basis of the density of the post-synaptic thickening and the nature of the post-synaptic target. A 3-dimensional stereological probe was used (the 'disector') to calculate Nvsyn, and mean projected height (Hsyn) of the post-synaptic density (PSD). Mean values for each age and hemisphere were compared with a 2-way analysis of variance test using paired samples. A six-fold increase in Nvsyn was seen between 16 days in ovo, and 9 days post-hatch. There was a hemispheric asymmetry at 9 days post-hatch, with the left hemisphere LPO containing 1.6 times as many synapses per micron-3. There was a subsequent period of reduction in synaptic density in the left hemisphere LPO between 9 and 22 days post-hatch. The Nv of all classes of synapse increased with age, but the proportions of the symmetrical synapses with respect to the total number of synapses, decreased with age. This decrease was of a similar magnitude for each hemisphere. A hemispheric difference was seen in post-hatch asymmetric synapses, with a greater proportion of asymmetric spine synapses in the left hemisphere. The magnitude of the hemispheric asymmetry was constant throughout the 3 week period of post-hatch development, but was not present in pre-hatch chicks. The PSD increased in length in each hemisphere by approximately 40% between post-hatch day 1 and post-hatch day 9. These data show that the LPO contains a synaptic population which undergoes substantial modification during the first week post-hatch. An asymmetry exists at post-hatch day 9 which is not present at the earlier ages investigated, nor indeed after 22 days post-hatch. This may have significance with regard to studies of passive avoidance learning in the one-day old chick, where an increase in both the size and number of synapses in the LPO has been demonstrated (Stewart et al. 1987).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

The recycling of a secretory granule membrane protein.

We have used N-hydroxysuccinimido-d-biotin as a reagent for labeling proteins exposed at the surface of cultured bovine adrenal chromaffin cells during Ba2+-stimulated secretion. A specific secretory granule membrane constituent, dopamine-beta-hydroxylase (DBH), has been investigated using immunoprecipitation followed by electrophoresis. Within 30 min of stimulation, exposed DBH had been cleared from the cell surface. Nevertheless, quantitation of labeled DBH using [125I] streptavidin suggested that it remained undegraded over a period of 24 h, a time during which secretory granule stores of catecholamines were being replenished. Subcellular fractionation of the cultured cells suggested that, after 3 or 4 h, the biotinylated DBH, which was still membrane-bound, was located in particulate material that also contained cytochrome b561, another major secretory granule membrane component.

Adrenal Medulla↗
PubMed1988

XY sex reversal syndrome in the mare: clinical and behavioral studies, H-Y phenotype.

An inherited genetic disorder causes XY embryos of the horse to develop as mares. On the basis of our study of 38 such mares, we have identified four grades or classes of XY sex reversal according to this scheme: class I, nearly normal female, of which some are fertile; class II, female with gonadal dysgenesis, normal mullerian development; class III, intersex mare with gonadal dysgenesis, abnormal mullerian development, enlarged clitoris; class IV, virilized intersex characterized by high levels of testosterone. In general, class I and class II mares were typed H-Y antigen-negative whereas class III and class IV mares were typed H-Y antigen-positive.

Animals↗
PubMed1987

Brain death.

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Brain Death↗
PubMed1986

A quantitative morphological study of interstrain variation in the developing rat optic nerve.

Groups of pigmented (Black and White Hooded Lister) and albino (Sprague Dawley) rats were killed at 7, 15, and 25 postnatal days of age. Their optic nerves were embedded in resin suitable for both light and electron microscopy. Quantitative stereological procedures were used to estimate total fibre number and the degree of myelination in the optic nerves at the various ages. At 7 days of age, both albino and pigmented rats had about 220,000 optic nerve fibres. By 15 days, both strains showed a reduction of some 30,000 fibres. This fibre loss continued in both strains after 15 days of age, but more rapidly in the pigmented strain. At 25 days of age, pigmented rats had 72,371 +/- 7,244 fibres, whilst albino rats had 102,681 +/- 4,138 fibres (P less than .01). More than 99.5% of optic nerve axons in both strains were unmyelinated at 7 days of age. By 25 days of age about 90% of all remaining fibres were myelinated in both strains. The mean diameter of the myelinated axons was estimated to be between 0.59 and 0.65 micron in all animals, there being no significant age or strain differences. In contrast, the mean diameter of nonmyelinated axons increased significantly with age. This increase was greater for albino than pigmented rats, such that by 25 days of age the respective values were 0.49 micron and 0.42 micron (P less than .05).

Aging↗
PubMed1986

Immunological and biosynthetic studies on the mammalian 2-oxoglutarate dehydrogenase multienzyme complex.

High-titre, monospecific, polyclonal antisera have been raised against purified mitochondrial 2-oxoglutarate dehydrogenase complex (OGDC) from ox heart and two of its three constituent enzymes, 2-oxoglutarate dehydrogenase (E1) and lipoyl succinyltransferase (E2). These specific antisera have been employed to monitor molecular events in the biosynthesis, import and maturation of this multimeric assembly. Lipoamide dehydrogenase (E3) elicits a poor antibody response in comparison to the other polypeptides of the complex. In cultured pig kidney cells (PK-15), incubated with [35S]methionine in the presence of uncouplers of oxidative phosphorylation, appearance of stable higher-Mr forms of the individual enzymes can be detected by specific immunoprecipitation and fluorographic analysis. In the case of 2-oxoglutarate dehydrogenase, E1, the initial cytoplasmic translation product has a subunit Mr value of 1500-3000 greater than in the mature enzyme while the precursor of the lipoyl succinyltransferase, E2, contains an additional sequence of Mr 6000-8000. Competition studies have revealed the immunological similarity of the precursor molecules to the native subunits. On removal of uncouplers, processing of accumulated precursors is rapidly initiated and is complete within 40 min. Interestingly, antiserum to native 2-oxoglutarate dehydrogenase complex fails to recognise E2 precursor molecules (pre-E2), which can be immunoprecipitated, however, by antibodies raised against the denatured E2 subunit. It is concluded that pre-E2 is conformationally dissimilar to native E2, which exists normally as a highly ordered, multimolecular aggregate in the native complex.

Animals↗
PubMed1986

The meaning of community in community mental health.

This article critically reviews the development of community mental health in both theory and practice and explores new directions and dilemmas for future policy and programs. First, we trace the dialectical development of the ideology of community mental health and the rediscovery of community. Second, we outline the two key transitions: (a) from professionals to natural helpers and (b) from catchment areas to natural networks. Third, we offer alternative conceptions of community from the sociological literature and suggest ways that these can benefit new program planning. We conclude with a series of policy questions that legitimate the expansion of community mental health beyond the parochial confines of the local community.

Catchment Area, Health↗
PubMed1986

A multicenter trial of immunotherapy with alginate--conjugated grass pollen extract.

Conjuvac, a new generation of allergen extracts, has been developed to meet the need for improved characterization, purification, and standardization. Conjuvac consists of a dialyzed, standardized aqueous allergen extract chemically conjugated to a sodium alginate carrier and lyophilized in single-dose vials, thus ensuring stability until reconstituted with sterile water just before each injection. A preliminary study of Conjuvac 2 Grass by Pegelow (1984) involving a small number of patients showed this extract to have potential advantages. Accordingly, a study involving more patients was undertaken: two different maintenance dose levels of Conjuvac 2 Grass were investigated and compared to a pyridine-extracted, alum-precipitated two-grass extract called Allpyral, which in previous double-blind trials has been shown to be effective. The trial, which included 125 patients with hay fever and which extended over 2 years, involved ten allergists from seven European countries. Overall, the Conjuvac high-dose regimen proved slightly superior to Allpyral without any increased incidence of side effects, and all treatments stimulated marked increases in specific IgG levels without raising IgE levels.

Adolescent↗
PubMed1985

Toxicity of carbon disulfide in developing rats: LD50 values and effects on the hepatic mixed-function oxidase enzyme system.

The 24-hr LD50 values of carbon disulfide (CS2) were estimated in 1-, 5-, 10-, 20-, 30-, and 40-day-old rats. CS2 was least toxic to 20-day-old rats (LD50 1545 mg/kg, ip) and most toxic to 1-day-old rats (LD50 583 mg/kg, ip). Twenty-four hours after administration of CS2 (375 mg/kg, ip) to 1-, 5-, 10-, 20-, 30-, and 40-day-old rats, significant inhibition of cytochrome P-450 and aniline hydroxylation was observed in rats of all ages studied except the 1-day-old rats. Following incubation of hepatic microsomes isolated from 1-, 5-, 10-, 20-, 30-, and 40-day-old rats with CS2, decreases in activity of the hepatic mixed-function oxidase enzyme system and/or concentration of cytochrome P-450 were observed when an NADPH-generating system was present during incubation. When hepatic microsomes isolated from rats of all ages studied were incubated with C35S2, 35S was covalently bound to microsomal protein in the presence of an NADPH-generating system. Also, more 35S than 14C was covalently bound to microsomal membranes after incubation of microsomes isolated from rats of all ages studied with C35S2 or 14CS2 in the presence of an NADPH-generating system. The results of this research demonstrated the LD50 of CS2, the effects of CS2 on the hepatic mixed-function oxidase enzyme system, and that the conversion of CS2 to a covalently binding sulfur-containing biotransformation product varied with age in developing rats.

Aging↗
PubMed1985

Low immunogenicity of the common lipoamide dehydrogenase subunit (E3) of mammalian pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase multienzyme complexes.

The production of high-titre monospecific polyclonal antibodies against the purified pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase multienzyme complexes from ox heart is described. The specificity of these antisera and their precise reactivities with the individual components of the complexes were examined by immunoblotting techniques. All the subunits of the pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase complexes were strongly antigenic, with the exception of the common lipoamide dehydrogenase component (E3). The titre of antibodies raised against E3 was, in both cases, less than 2% of that of the other subunits. Specific immunoprecipitation of the dissociated N-[3H]ethylmaleimide-labelled enzymes also revealed that E3 alone was absent from the final immune complexes. Strong cross-reactivity with the enzyme present in rat liver (BRL) and ox kidney (NBL-1) cell lines was observed when the antibody against ox heart pyruvate dehydrogenase was utilized to challenge crude subcellular extracts. The immunoblotting patterns again lacked the lipoamide dehydrogenase band, also revealing differences in the apparent Mr of the lipoate acetyltransferase subunit (E2) from ox kidney and rat liver. The additional 50 000-Mr polypeptide, previously found to be associated with the pyruvate dehydrogenase complex, was apparently not a proteolytic fragment of E2 or E3, since it could be detected as a normal component in boiled sodium dodecyl sulphate extracts of whole cells. The low immunogenicity of the lipoamide dehydrogenase polypeptide may be attributed to a high degree of conservation of its primary sequence and hence tertiary structure during evolution.

Animals↗
PubMed1984

The effect of thioacetamide on sulfobromophthalein and ouabain transport in isolated rat hepatocytes.

The uptake and release of sulfobromophthalein (BSP) and ouabain were studied in hepatocytes isolated from rats which received thioacetamide (TA) (1, 2 or 4 mmol/kg) 6, 12, 24, 48 or 72 h before sacrifice. The effects of TA (1 mmol/kg) on hepatocyte BSP transport varied with time. Total BSP hepatocyte content was decreased 6 h and 24 h after TA treatment and increased 48 h after TA treatment due to decreased and increased uptake, respectively. Hepatocyte BSP conjugation was increased 6 h and 24 h after TA treatment and decreased at 48 h. At the higher doses of TA, 24 h after treatment total BSP hepatocyte content was increased and concomitantly BSP release was decreased at the 4 mmol/kg dose of TA. Ouabain uptake was decreased at all doses of TA and at all treatment times. However, release of ouabain was not altered by TA treatment. These results show TA depresses hepatocyte total BSP uptake (depending on dose and time factors) and depresses hepatocyte ouabain uptake.

Acetamides↗