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Biomedical subjects

C Oliver

Publications and source records attributed to C Oliver.

At least 325 records · Page 18Linked to original sources
PubMed1980

Taste, smell and zinc metabolism in patients with chronic renal failure.

Taste and smell acuity, and zinc concentrations in blood, plasma, red blood cells, and hair were determined in male patients with end stage renal disease (n = 7), male (n = 20) and female (n = 6) patients on maintenance hemodialysis (HD), and male (n = 23) and female (n = 25) control groups. Taste acuity for salt (NaCl), sweet (sucrose), acid (HCl) and bitter (urea) in all 3 patient groups was lower than in the appropriate control group. These differences were significant only for sucrose (male dialysis, p < 0.05), HCl (male uremics not on dialysis, p < 0.01; male dialysis, p < 0.01; and female dialysis, p < 0.05) and urea (male dialysis, p < 0.01). Smell perception was impaired (not significantly) for the male patient groups, but slightly improved (not significantly) for the female patient group. Red blood cell and hair Zn++ concentrations were elevated for the male HD group (p < 0.001). THe plasma zinc concentration was significantly lowered for the male patient groups (p < 0.05). Age showed a negative correlation with pyridine, NaCl, sucrose, and HCl mean detection levels for both male HD patients and control groups. Sensitivity to urea also decreased with age for male HD patient groups, but increased for the male control group. Blood and RBC Zn++ concentrations increased and plasma and hair Zn++ decreased with age for the male HD patients and the male control group. No correlation was observed between Zn++ concentrations and taste and smell mean detection levels.

Adult↗
PubMed1980

Brain TRH levels during development of the rat, in neonatal hypothyroidism and after caloric deprivation.

The effect of neonatal hypothyroidism and neonatal caloric deprivation on brain TRH levels and serum and pituitary TSH levels has been determined in rats on the following postnatal days: 1, 5, 10, 15, 25, 40 and 60. After neonatal hypothyroidism, there was a slight reduction in brain TRH content although TRH concentration in the brain increased. Serum TSH was elevated at birth, suggesting that the feedback of thyroid hormones on the pituitary gland acts in rat fetuses. After neonatal caloric deprivation, a decrease in brain TRH content was observed along with a decrease in circulating TSH levels, however, there was no change in brain TRH concentration.

Aging↗
PubMed1980

Developmental changes in brain TRH and in plasma and pituitary TSH and prolactin levels in the rat.

TRH in the hypothalamus and the rest of the brain, as well as TSH and prolactin in the pituitary gland and the plasma have been determined by radioimmunoassay in rats varying in age (10- to 22-day-old fetuses and 1- to 60-day-old rats). TRH is first detected on the 16th day of gestation and its maximum increase occurs during the first 3 weeks of life both in the hypothalamus and the rest of the brain. The evolution patters of TSH and prolactin in the plasma and the pituitary gland are discussed in relation to TRH levels in the brain and in the hypothalamus.

Aging↗
PubMed1980

Cytochemical localization of acid phosphatase and trimetaphosphatase activities in exocrine acinar cells.

Acid phosphatase activity, a lysosomal marker, is commonly demonstrated using the Gomori technique with cytidine 5'-monophosphate or beta-glycerophosphate as substrate. Using this lead capture method on mouse and rat exorbital lacrimal, parotid, and pancreatic acinar cells, reaction product was localized in GERL, forming secretory granules, and secondary lysosomes. However, a different cytochemical localization was observed for inorganic trimetaphosphatase, another lysosomal enzyme. When the technique for trimetaphosphatase activity, a metal chelation method, was applied to exocrine acinar cells, reaction produce was conspicuously absent from GERL and forming secretory granules, but was present in secondary lysosomes, occasionally in Golgi saccules, and in previously unreported basal elongated lysosomes. The differences in the localization of the two enzymatic activities emphasizes the importance of employing more than one substrate where possible, and raises questions concerning the mechanism of delivery of acid hydrolases to secondary lysosomes.

Acid Anhydride Hydrolases↗
PubMed1980

Influence of corticotrophin on plasma testosterone in normal women.

The concentrations of ACTH and testosterone (T) in the plasma from 12 normal women (aged 18-35 years) were simultaneously determined at various times after im injection of 1 mg corticotrophin. The increase in the plasma level of total immunoreactive ACTH was maximal 0.5 h after the injection (mean value 1123 as compared to 36 pg/ml in the basal state); at 48 h, the ACTH level was still 2.4-fold that measured in the basal state. The administration of corticotrophin induced a broad increase in the mean level of plasma T which was highly significant (P < 0.001) at 4, 6, 8, 16 and 24 h after the injection. The maximum T response was detected at 16 h (mean value 477 as compared to 338 pg/ml in the basal state). The results indicate that plasma T is susceptible to stimulation by a pharmacological dose of ACTH in normal women. This effect should be taken into account in evaluating the indication of ACTH as a therapeutic agent.

Adolescent↗
PubMed1979

Distribution of alpha-melanocyte-stimulating hormone in the rat brain: evidence that alpha-MSH-containing cells in the arcuate region send projections to extrahypothalamic areas.

The distribution and concentration of alpha-MSH in the rodent brain has been determined by radioimmunoassay. The limbic system contained substantial quantities of alpha-MSH. Forty per cent of the alpha-MSH present in the brain was localized in the hypothalamus, with the highest concentration of alpha-MSH in the arcuate nucleus. More than 40% of the extrahypothalamic alpha-MSH in the brain was found in the following areas: midbrain (16%), preoptic area (13%), septum (7%), and thalamus (7%). To determine the source of the hypothalamic and extrahypothalamic alpha-MSH, the anterior hypothalamic preoptic area of the brain was surgically separated from more caudal diencephalic structures, and the arcuate region of the hypothalamus was surgically isolated from the remainder of the brain. Following these deafferentations, no significant reduction in hypothalamic alpha-MSH levels was observed; however, a significant reduction in extrahypothalamic alpha-MSH level was demonstrated. This dramatic decrease of alpha-MSH in extrahypothalamic areas of the rodent brain strongly suggests that the bulk of the extrahypothalamic alpha-MSH arises from neuronal perikarya in the arcuate region. These findings are consistent with the hypothesis that a population of neuronal cell bodies producing alpha-MSH originate in the arcuate region of the hypothalamus and that they send axonal projections to many areas of the limbic system and brain stem.

Animals↗
PubMed1979

Release of immunoreactive alpha-MSH by synaptosome-enriched fractions of homogenates of hypothalami.

Immunoreactive alpha-melanocyte-stimulating hormone (alpha-MSH) was found to be concentrated in a synaptosome-enriched fraction prepared by differential centrifugation of rat hypothalamic homogenates. The release of the hormone from this preparation was investigated. After incubation, the synaptosomes were isolated by ultrafiltration and alpha-MSH in the ultrafiltrate was determined by radioimmunoassay. Particle-bound alpha-MSH, recovered by extraction with acid ethanol, and alpha-MSH released from the synaptosome preparation, were immunologically similar to synthetic alpha-MSH and had an accompanying melanotropic activity. Less than 10% of the particle-bound alpha-MSH was released during incubation in 0.32 M sucrose. However, in the presence of 2 mM Ca2+, alpha-MSH release increased with increasing concentrations (30-150 mM) of K+. The stimulatory effect of 60 mM K+ was complete within 2 min and was potentiated by increasing Ca2+ concentrations over the range of 0 to 2 mM. K+-induced release of alpha-MSH was independent of temperature from 1 to 30 degrees C, and neither glucose (10 mM) nor dopamine (10(-10)-10(-2) M) had any effect on the release of the peptide. It is concluded that a synaptosome-enriched fraction from the hypothalamus contains a releasable pool of immunoreactive alpha-MSH that is mobilized by depolarizing concentrations of K+ in a Ca2+-dependent manner.

Animals↗
PubMed1979

[Distribution of thyrotropin releasing hormone (TRH), alpha-melanocyte-stimulating hormone (alpha-MSH) and somatostatin in the skin of the green frog (Rana esculenta)].

High concentrations of Thyrotrophin-Releasing Hormone (TRH) have been found in the dorsal skin of the Frog Rana esculenta, lower levels being measured in the ventral skin. alpha-MSH and somatostatin were undetectable in these tissues. Nor was TRH detected in the blood of these animals. The concentration of somatostatin in the pancreas was similar to that of the hypothalamus and twice or one hundred times higher than in the intestine or stomach respectively.

Animals↗
PubMed1979

Formation and fate of ethionine-induced cytoplasmic crystalloids in rat parotid acinar cells.

The formation and fate of cytoplasmic crystalloids in rat parotid acinar cells were investigated during ethionine intoxication and recovery. By day 3 of ethionine treatment, acinar cells had numerous autophagic vacuoles containing recognizable secretory granules and fragments of rough endoplasmic reticulum. By day 5, immature crystalloids were present in many of the autophagic vacuoles, and as the crystalloids matured, a 7-nm periodicity became apparent. Crystalloids were never observed in the Golgi saccules or in any other organelle associated with secretory granule formation. When ethionine treatment was stopped, the acinar cells rapidly returned to their normal morphology. The majority of the crystalloids and autophagic vacuoles were lost from the cells during the first two to three days of recovery. At this time annulate lamellae were present intracellularly, and macrophages, many containing crystalloids, were associated with the basal surface of the acinar cells. These results indicate that the cytoplasmic crystalloids are formed in autophagic vacuoles, and do not represent an abnormal secretory product. Additiontionally, during recovery crystalloids may be removed from the acinar cells by interaction with macrophages. The sequence of autophagic vacuole formation, development of crystalloids, macrophage infiltration and phagocytosis of acinar cell debris appears to be a non-specific response of the rat parotid gland to cellular injury occurring in a variety of experimental and pathological conditions.

Animals↗
PubMed1979

Localization of neurophysin within organelles associated with protein synthesis and packaging in the hypothalamoneurohypophysial system: an immunocytochemical study.

Electron microscopic immunocytochemical localization of neurophysin in the hypothalamo-neurohypophysial system of mice has been studied by using the pre-embedding staining approach to the unlabeled antibody-enzyme technique of Sternberger. In supraoptic cell bodies, peroxidase-antiperoxidase reaction product was localized within cisternae of the nuclear envelope, rough endoplasmic reticulum, and Golgi saccules but not in GERL (Golgi-associated smooth endoplasmic reticulum from which lysosomes arise). Reaction product was also present in secondary lysosomes. Secretory granules in supraoptic perikarya and posterior pituitary Herring bodies were likewise immunoreactive. These findings with the unlabeled antibody-enzyme technique provide conclusive evidence for the localization of an antigen within cellular organelles associated with protein synthesis and packaging.

Animals↗
PubMed1979

Immunoreactive somatostatin in rat hypophysial portal blood.

Somatostatin levels have been determined by RIA in hypophysial portal blood of pentobarbital-anesthetized male rats. In most animals, immunoreactive somatostatin (SRIF) levels were higher in hypophysial portal blood than in systemic blood. In euthyroid rats, the mean level was 158 +/- 27 pg/ml (n = 8); SRIF was undetectable (less than 30 pg/ml) in systemic blood of these rats. It is suggested that endogenous SRIF was not degraded during the collection of stalk blood, since synthetic SRIF is stable when incubated in rat serum during 4 min at 37 c and 2 h at 0 C, i.e. under the conditions the blood was kept during the collection. SRIF in hypophysial portal plasma had the same immunoreactivity with a specific antiserum against SRIF as did synthetic SRIF. Gel filtration of hypophysial portal plasma revealed two immunoreactive peaks, the major one corresponding to synthetic SRIF, the smaller one representing a larger molecular form. Thyroidectomy and excess of T4 did not modify the levels of SRIF in hypophysial portal blood, suggestinc SRIF is stable when incubated in rat serum during 4 min at 37 C and 2 h at 0 C, i.e. under the conditions the blood was kept during the collection. SRIF in hypophysial portal plasma had the same immunoreactivity with a specific antiserum against SRIF as did synthetic SRIF. Gel filtration of hypophysial portal plasma revealed two immunoreactive peaks, the major one corresponding to synthetic SRIF, the smaller one representing a large molecular form. Thyroidectomy and excess of T4 did not modify the levels of SRIF in hypophysial portal blood, suggesting that the feedback of thyroid hormones on TSH secretion does not involve changes in the secretion of SRIF by the hypothalamus.

Animals↗