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Biomedical subjects

L G Davis

Publications and source records attributed to L G Davis.

At least 91 records · Page 5Linked to original sources
PubMed1980

Hemodialysis and schizophrenia: a double-blind study.

Partial or total remission of schizophrenic symptoms after exchange transfusion or hemodialysis have been reported in the literature. Although the results of these reports are encouraging, they have not been confirmed by controlled studies. We have conducted a double-blind placebo-controlled study to evaluate the effect of hemodialysis on chronic schizophrenia. Our data seem to indicate that some schizophrenic symptoms improve after hemodialyses.

Adult↗
PubMed1980

Delusional misidentification and platelet monoamine oxidase.

Recently, reduced platelet monoamine oxidase (MAO) activity was demonstrated in two cases of paranoid schizophrenia exhibiting Capgras' syndrome. The present authors report platelet MAO studies in an additional patient with the Delusion of Doubles. In this case, one of delusional hyperidentification (false recognition), decreased platelet MAO activity compared with normal controls was detected. The patient, while not schizophrenic, showed platelet MAO activity comparable with that of a chronic schizophrenic control group. The possible significance of the findings are discussed.

Adult↗
PubMed1979

A regional study of electrophoretically separated proteins from the crude synaptosomal fractions of the developing rat brain.

Albino rats of 1, 5, 9, 16, and 25 days of age were sacrificed, and six brain regions were dissected free. Crude synaptosomal preparations from each brain region and age were obtained by differential centrifugation. Protein content in these fractions from the six brain regions increased almost threefold between 1 and 25 days of age. The preparations were delipidated, solubilized, and subjected to polyacrylamide gel electrophoresis. The densitometric patterns of five samples from each age and brain region were analyzed for changes in the relative amount of stained protein bands. Of the polyacrylamide gel-separated protein bands, 16 regional differences at specific ages and 20 developmental changes in specific brain regions were found to be statistically significant. The hippocampal region showed the greatest number of statistical changes in the protein pattern as a function of age, whereas the cerebellum showed none. The results suggest the importance of considering regional differences in studies of biochemical developmental changes.

Age Factors↗
PubMed1979

Endorphins, dopamine, and schizophrenia.

The theory that alterations of dopaminergic synaptic transmission may play a role in the pathogenesis of schizophrenia is widely accepted. A more recent theory links the endorphin system to the etiology of schizophrenia. We propose that these two theories may be combined into a single model. Recent neurochemical and pharmacological findings have indicated close functional relationships between the endorphin and dopamine systems. Endorphins modulate dopaminergic synaptic transmission by exerting both presynaptic and postsynaptic effects. On the molecular level, this modulation may involve the activity of nucleotide cyclases and protein phosphorylation systems. Thus, the dopaminergic neuronal hyperactivity, currently believed to be related to schizophrenia, may be caused by a primary alteration in the endorphin system. Several hypotheses about the nature of that alteration have been advanced and tested in therapeutic experiments with schizophrenic patients. These experiments have not yet yielded definitive results.

Antipsychotic Agents↗
PubMed1979

Gas-liquid chromatographic determination of mono- and diiodotyrosines in serum.

A sensitivie, reliable gas-chromatographic assay for monoiodotyrosine and diiodotyrosine in human serum is reported. The oxazolidinone-heptafluorobutyric anhydride derivatives allow the quantitation of both compounds in the linear range of 0.2 to 7.6 mg/L of serum. Analytical recovery averaged 88%, and mean accuracy and within-run precision were 98 and 2%, respectively. Concentrations of monoiodotyrosine in serum as low as 20 microgram/L and of diiodotyrosine as low as 100 microgram/L can be detected. Normal serum contains no detectable concentration of either compound, but the method is applicable as a diagnostic tool in the early prediction of thyroid disease. Both compounds were detected in the serum of a hypothyroid subject whose normal thyroid hormone concentrations were being maintained by therapy with desiccated thyroid extract.

Butyrates↗
PubMed1978

Selective changes in the phosphorylation of endogenous proteins in subcellular fractions from cyclic AMP-induced differentiated neuroblastoma cells.

The endogenous phosphorylation of specific proteins was studied in subcellular fractions from proliferating and cAMP-induced differentiated neuroblastoma cells. Fractions containing nuclear, membrane-bound, and cytosolic proteins were incubated with [gamma-32P]ATP, in the presence and absence of added cyclic nucleotides. Phosphate incorporation into specific proteins was determined by slab-gel electrophoresis of sodium dodecyl sulfate-solubilized reaction products. Cytosol fractions from differentiated cells demonstrated a twofold increase in cAMP-dependent phosphorylation of a specific protein with apparent mol wt of 59,000 daltons and a comparable decrease in cAMP-independent phosphorylation of another protein (97,000). The nuclear fraction of differentiated cells showed an increase in the cAMP-independent phosphorylation of two nonhistone proteins (110,000 and 102,000). Membrane fractions from differentiated cells exhibited a differential decrease in endogenous phosphorylation of specific proteins. Selective alterations in the phosphorylation of specific proteins in various subcellular components may be important biochemical events associated with the increased levels of differentiated functions in neuroblastoma cells in culture.

Cell Differentiation↗
PubMed1976

A study of 3H-L-flucose-containing glycoproteins of the crude synaptosomal fraction obtained from rat brain regions at various ages.

The frontal cortex showed a marked elevation of incorporation of 3H-L-fucose into glycoproteins of the crude synaptosomal fraction at 9 days of age. The effect was observed at both 8 and 24 hr after intraperitoneal administration of radioactive fucose. The elevation was absent in the 1, 5, 16, and 25-day-old frontal cortices. It was also absent in the hippocampus and cerebellum at all ages studied. Fucose-labeled glycoproteins of high molecular weight in the crude synaptosomal fraction, as separated by polyacrylamide gels,were preferentially labeled in the hippocampus, frontal cortex, and cerebellum at all ages studied. In general, these glycoproteins became less prominent in the oldest animals studied (25 days). However, the relative amount of these glycoproteins varied with age of the animal, time between administration of isotope and sacrifice, and with the brain areas studied.

Age Factors↗
PubMed1975

31-P nuclear magnetic resonance studies on serum low and high density lipoproteins: effect of paramagnetic ion.

A paramagnetic quenching reagent, Mn-2+/EDTA (1:2.2), was developed for the purpose of investigating the phospholipid phosphate groupings of human serum low and high density lipoproteins through the quenching effect of the reagent on the 31-P nuclear magnetic resonance signals from these complexes. Systems investigated included native low and high density serum liproteins (LDL, HDL2, and HDL3), egg phosphatidylcholine vesicles together with appropriate phosphodiester model systems, diethyl phosphate in aqueous buffer, and phosphatidylcholine and sphingomyelin both in anhydrous methanol. The results of these studies indicated that ca. 50 percent of the phospholipid-phosphorus signal of LDL is quenched upon titration as compared to an 80-85 percent figure observed for HDL2 and HDL3. In all cases the spectral effects were totally reversible upon removalof the paramagnetic ion by dialysis. The results of the titration studies indicated a similar but not an identical behavior between HDL2 and HDL3. The results are consistent with model structures of HDL and LDL particles derived from low angle X-ray diffraction.

Edetic Acid↗
PubMedDate not supplied

Cesarean section rates in low-risk private patients managed by certified nurse-midwives and obstetricians.

This study was designed to assess the impact of selected medical interventions during labor upon cesarean section rates by comparing the maternal and neonatal outcomes of obstetrician- and nurse-midwife-managed low-risk private patients. All patients who delivered at Prentice Women's Hospital in Chicago, Illinois, from January 1, 1987 through December 31, 1990 were evaluated for low-risk criteria to be included in the study. During that time, the nurse-midwives delivered 573 patients and the obstetricians delivered 12,077 patients. Patients with fetal and maternal complications known to increase the cesarean section rate were eliminated from both groups. Eight percent of the nurse-midwife patients and 32% of the physician patients were eliminated, leaving 529 nurse-midwife patients and 8,266 physician patients. These patients were compared for race, parity, age, and birth weight. Information was collected from a perinatal data base and hospital computerized statistics. The rates of cesarean section, administration of oxytocin, analgesia, anesthesia, and infant outcome data were compared by chi-square analysis. Multiple logistic regression analysis was used to assess factors that predicted cesarean section. Nurse-midwife-managed patients had a significantly lower rate of cesarean section (8.5% versus 12.9%; P < .005) and operative vaginal delivery (5.3% versus 17%, P = .0001) than the physician-managed patients. Epidural anesthesia and oxytocin for induction and augmentation were used significantly more frequently in the physician-managed patients. Both interventions were associated with an increased rate of cesarean section. Fetal outcomes in the two groups were not statistically different. Women cared for by nurse-midwives had a lower cesarean section rate, fewer interventions, and equally good maternal and infant outcomes when compared with those cared for by physicians.

Adult↗