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Biomedical subjects

S A Moore

Publications and source records attributed to S A Moore.

160 records · Page 9Linked to original sources
PubMed1980

A quantitative comparison of motor and sensory conduction velocities in short- and long-term streptozotocin- and alloxan-diabetic rats.

Motor and sensory conduction velocities were measured in the sural and tibial nerves of streptozotocin (stz)-diabetic, alloxan-diabetic, and age-matched control rats. Conduction velocity (CV) determinations were made 2 weeks and 2, 4, 8, and 12 months following the induction of diabetes. CVs of control, stz-diabetic, and alloxan-diabetic rats were compared at each time period by one way analysis of variance and when appropriate by the Newman-Keuls multiple range test for multiple comparisons. Reductions of 10-20% in CV of diabetic rats were observed in several classes of sensory and motor nerve fibers. Larger reductions (31 and 38%) were seen in 2 classes of sensory nerve fibers in 12 month stz-diabetic rats. Sensory CV was slowed earlier and more frequently than motor CV. Differential involvement was also seen among the several classes of sensory nerve fibers examined. Slower conducting sensory fibers appeared to be affected earlier and more frequently than faster conducting sensory fibers. Comparing alloxan-diabetic with stz-diabetic rats revealed significant differences in CV 8 months after the induction of diabetes. Motor and sensory CVs of the tibial nerve were slower in stz-diabetic rats than in alloxan-diabetic rats. In general, the neuropathy appeared to be less severe and to develop later in the alloxan-diabetic rats. These data suggest that the neuropathy of stz- and alloxan-diabetes is primarily sensory in nature, and that the neuropathy in these 2 widely used models of diabetes may not be entirely equivalent.

Alloxan↗
PubMed1979

An effective rabies treatment in exposed monkeys: a single dose of interferon inducer and vaccine.

Rhesus monkeys were injected with lethal doses of rabies virus and then treated with a variety of treatment combinations. The one found most successful was one dose of an interferon inducer (poly(I)-poly(C) complexed to poly-L-lysine and carboxymethyl-cellulose) and one dose of human diploid rabies vaccine. This combination proved to be as effective as hyperimmune serum and vaccine, and much better than vaccine alone. The combination of the interferon inducer plus vaccine could be administered at least up to 48 hours after the very severe challenge given and still provide marked protection.

Animals↗
PubMed1977

Successful prophylaxis against rabies in mice and Rhesus monkeys: the interferon system and vaccine.

Addition of interferon to ineffective rabies virus vaccines by the local injection of either exogenous interferon or a potent interferon inducer (a complex of polyriboinosinic-polyribocytidylic acid containing poly-L-lysine and carboxymethylcellulose) into the footpads of mice previously challenged with rabies virus dramatically reduced the mortality rate. A significant reduction in mortality rate was also noted when the interferon system was administered to rhesus monkeys, but only when treatment was given 6 hr after challenge with rabies virus. Since the monkeys were given an overwhelming challenge of virus, the treatment had to be given quickly to obtain results comparable to those in mice.

Animals↗
PubMedDate not supplied

Glycogen accumulation in tibial nerves of experimentally diabetic and aging control rats.

Tibial nerves of streptozotocin-diabetic, alloxan-diabetic, and age-matched control rats were examined at 2 weeks and 2, 4, 8, and 12 months following the induction of diabetes. Glycogen-like granules accumulated within perineurial and Schwann cells of only the diabetic animals. This accumulation may reflect a metabolic abnormality in these cells which could account for the reduced conduction velocities seen in the peripheral nerves of these same diabetic rats (Moore et al. 1980a). Glycogen-like granules were also present and increased with age in myelinated axons of both diabetic and control rats. Quantitative data suggest that axonal accumulation of glycogen-like granules is related to aging or injury related phenomena to which diabetic axons may be more susceptible.

Aging↗
PubMedDate not supplied

MRI spectrum of medulloblastoma.

Medulloblastomas have been characterized as solid, homogeneously enhancing, midline masses of the posterior fossa. To evaluate atypical MRI characteristics, we retrospectively reviewed 13 histologically proven medulloblastomas. MRI examinations were correlated with pathologic specimens and operative reports. Atypical features included cyst formation (77%), irregular enhancement (19%), extension through fourth ventricle foramina (15%), and presentation as a cerebellopontine angle mass (8%). We conclude that "atypical" characteristics are common. In the child or young adult, medulloblastomas must be included in the differential diagnosis of any posterior fissa mass.

Adult↗
PubMedDate not supplied

Estrogenic tamoxifen derivatives: categorization of intrinsic estrogenicity in MCF-7 cells.

Triarylethylenes bearing acetic acid side chains, exemplified by 4-[1-(p-hydroxyphenyl)-2-phenyl-1-butenyl]phenoxyacetic acid (4HTA), a derivative of tamoxifen (TAM), are of current interest as estrogen mimics lacking reproductive tract effects. Affinities for estrogen receptors (ER) and effects on cell growth kinetics of a diverse series of such compounds were compared with 4HTA, TAM, and with standard estrogens 17beta-estradiol (E2) and chlorotrianisene (CTA) in MCF-7 cells. These compounds exhibited concentration dependent cell growth stimulation comparable to that of CTA but less than that of E2. Growth stimulation of the more potent compounds was antagonized by TAM, signifying that effects were mediated via interaction with ER. At concentrations of 1 microM or higher, compounds with efficacies less than that of E2 were weak antagonists of estradiol-stimulated growth. Both intracellular ER affinities and growth rate stimulation potencies of the triarylethylene acetic acids and the standard ER ligands varied over a range of nearly three orders of magnitude. Analysis of growth stimulatory potency as a function of ER affinity revealed dual parallel correlations: the potency/ER affinity ratios of 4HTA and four of its analogues was about 100-fold less than those of the hydroxytriarylethane and bisphenolic analogs and the three standard ER ligands. These results suggested that ER liganded with the latter substances is more 'effective' at nuclear effector sites than is ER liganded with 4HTA and the other acidic triarylethylenes.

Breast Neoplasms↗
PubMedDate not supplied

Demonstration of adenosine receptors on mouse cerebral smooth muscle membranes.

Adenosine receptors have been identified on brain cortical membranes and microvascular preparations. However, they have not been demonstrated on specific microvascular elements in isolation. 2-3H-chloroadenosine was used as a ligand to investigate the presence of adenosine receptors on isolated mouse cerebral smooth muscle membranes. The binding studies reveal the presence of a high affinity binding site with a Kd value of 33.3 nM and a maximal binding capacity (Bmax) of 283 fmol/mg protein. These findings demonstrate that there is an adenosine receptor on cerebral smooth muscle membranes.

2-Chloroadenosine↗
PubMedDate not supplied

Polyunsaturated fatty acid synthesis and release by brain-derived cells in vitro.

The brain is more highly enriched than most other tissues in long-chain polyunsaturated fatty acids (PUFA), particularly docosahexaenoic acid (DHA). In vitro studies of PUFA synthesis and release utilizing cell cultures of astrocytes, neurons, and cerebral microvascular endothelium have contributed significantly to our understanding of mechanisms potentially involved in the accretion of PUFA in brain. Both cerebral endothelium and astrocytes avidly elongate and desaturate precursors of the long-chain PUFAs when grown individually or in various co-culture combinations. The products, such as arachidonic acid (AA) and DHA, are released from the cells. In contrast, neurons appear unable to carry out fatty acid desaturation and thus are dependent upon preformed long-chain PUFA. Indeed, neurons co-cultured with astrocytes accumlate docosahexaenoate synthesized by the glial cells. Cerebral endothelial cultures are additionally capable of enriching the basolateral compartment (analogous to the brain extracellular space) with n-3 PUFA when grown in a membrane/chamber apparatus. The enrichment of this compartment with DHA is increased when cerebral endothelium is co-cultured with astrocytes. These data suggest that endothelial cells and astrocytes cooperate in the local synthesis and release of PUFA, collectively maintaining a brain environment enriched in long-chain PUFA.

Animals↗
PubMedDate not supplied

Brain uptake and utilization of fatty acids: recommendations for future research.

A primary goal of the international workshop "Brain Uptake and Utilization of Fatty Acids" was to identify research areas that would benefit from further investigation. The major themes for future research are presented below: (1) Elucidating the role of the developing and mature cerebrovascular endothelium (CVE) in the uptake of fatty acids (FA) into the brain. (2) Clarifying the role of diffusion and receptor-mediated uptake of FAs by various brain cell membranes and protein-mediated shuttling of FAs between the CVE and various brain cells and tissues. (3) Illuminating the mechanisms of intermediate metabolism and the roles of polyunsaturated fatty acids (PUFA) in astrocytes, neurons and oligodendrocytes. Of special interest are the long-chain omega-3 PUFA and their derivatives, such as lipoproteins, phospholipids and plasmalogens, that have been associated with various disease states (such as those listed in [5], below). (4) Elucidating the role of gene expression on long-chain omega-3 PUFA incorporation in membranes and the regulatory role these and other PUFA have on gene expression in the brain. (5) Elucidating the recently identified roles of long-chain omega-3 PUFA in mood disorders, schizophrenia, stroke, peroxisomal biogenesis disorders, Huntington's disease, other neurodegenerative disorders and disorders of oxidative stress. (6) Undertaking placebo-controlled clinical trials to assess the therapeutic potential of omega-3 PUFA in the above disorders. (7) Developing new, and utilizing existing animal models in the above studies. (8) Developing noninvasive imaging and tagging methods for quantifying the migration and distribution of PUFA and their derivatives in the brain. (9) Applying multi-disciplinary collaborations among biophysicists, physiologists and molecular biologists to the resolution of the above.

Animals↗
PubMedDate not supplied

Brain uptake and utilization of fatty acids: applications to peroxisomal biogenesis diseases.

The brain is rich in diverse fatty acids saturated, monounsaturated and polyunsaturated fatty acids with chain lengths ranging from less than 16 to more than 24 carbons that make up the complex lipids present in this organ. While some fatty acids are derived from endogenous synthesis, others must come from exogenous sources. The mechanism(s) by which fatty acids enter cells has been the subject of much debate. While some investigators argue for a protein-mediated process, others suggest that simple diffusion is sufficient. In the brain, uptake is further complicated by the presence of the blood-brain barrier. Brain fatty acid homeostasis is disturbed in many human disorders, as typified by the peroxisomal biogenesis diseases. A workshop designed to bring together researchers from varied backgrounds to discuss these issues in an open forum was held in March, 2000. In addition to assessing the current state of knowledge, areas requiring additional investigation were identified and recommendations for future research were made. A brief overview of the invited talks is presented here.

Animals↗
PubMedDate not supplied

Occult invasive pituitary adenoma predisposing to fatal bacterial meningitis.

Pituitary adenomata are benign neoplasms which usually grow slowly and present with manifestations relating to an associated endocrinopathy or visual disturbance. Rarely these neoplasms will demonstrate a more aggressive behavior with extracranial extension and symptoms of upper airway obstruction or anosmia. Several reported cases suggest that although these neoplasms behave aggressively the overall survival and prognosis for these patients remains good. We present the clinical and postmortem findings of an occult invasive pituitary adenoma leading to the development of bacterial meningitis, coma and death. This communication stresses the necessity for the early diagnosis and treatment of the invasive adenomata to prevent the development of potentially fatal infectious sequelae.

Adenoma↗
PubMedDate not supplied

Sudden death from choroid plexus vascular malformation hemorrhage: case report and review of the literature.

A case of primary intraventricular hemorrhage in a previously healthy 13-year-old boy due to rupture of a choroid plexus vascular malformation is described. Review of the literature reveals that individuals with choroid plexus malformations usually present under age 40 with serious neurological symptoms. Sudden death, however, is an unusual outcome. This case and literature review illustrate the importance of early clinical recognition and surgical intervention. Choroid plexus should be microscopically examined at autopsy in any individual in which the cause of intracerebral hemorrhage is not clear, since the gross recognition of choroid plexus vascular malformations may be quite difficult.

Adolescent↗