[Anaphylactic shock caused by dextran during resuscitation of diabetic acidosis decompensation].
Explore the source record for details and available documents.
Anaphylaxis↗
Biomedical subjects
C Oliver
Publications and source records attributed to C Oliver.
Studies on the secretion of corticotropin-releasing factor into hypophysial portal blood.
Explore the source record for details and available documents.
Adrenocorticotropic Hormone↗
Interaction of vasoactive intestinal peptide (VIP) and growth hormone releasing factor (GRF) with corticotropin releasing factor (CRF) on corticotropin secretion in vitro.
The possible interaction of VIP and GRF with CRF on ACTH release was examined by using superfused rat anterior pituitary fragments. ACTH was measured in effluent medium samples by RIA. Increasing concentrations of VIP and GRF (10(-8) to 10(-6)M) had no effect on spontaneous ACTH secretion but potentiated CRF (10(-10)M) induced ACTH release in a dose dependent manner. The high concentrations of VIP or GRF required to produce the effect suggest that both the peptides could interfere with a common unidentified binding site on corticotrophs or stimulate a second messenger by a paracrine action.
Adrenocorticotropic Hormone↗
Auditory P300 response in the assessment of Alzheimer's disease in Down's syndrome: a 2-year follow-up study.
Sixty-five subjects with Down's syndrome were followed up and retested 2 years after the initial recording of auditory P300 (P3) event-related potential described in a companion paper (Blackwood et al., 1988). The number of subjects showing clinical evidence for Alzheimer's type dementia had increased by a further 14%. In subjects showing clinical deterioration over a period of 2 years, 78% (7/9) had an increase in P3 latency which was three standard deviations or greater than the group mean. None of the 20 fragile-X group retested showed significant change after 2 years. The results suggest that P3 change may be a sensitive index of the onset of Alzheimer's type dementia in Down's syndrome.
Adolescent↗
Central catecholaminergic system stimulates secretion of CRH at different sites.
To explore a possible differential role of distinct catecholamine (CA) innervation sites in corticotropin-releasing hormone (CRH) secretion, especially under stress conditions, we compared the effects in adult female rats of selective CA denervation of either the whole hypothalamus, by a discrete pharmacological lesion of the ventral noradrenergic ascending bundle [VNAB; 3 micrograms of 6-hydroxydopamine (6-OHDA) in 0.2 microliter of vehicle, bilaterally] or of the paraventricular nuclei (PVN) alone (1 microgram of 6-OHDA in 0.2 microliter of vehicle, bilaterally). Although both procedures induced a similar dramatic fall in norepinephrine and epinephrine concentrations (-55 to -65%) measured by high-performance liquid chromatography in PVN punches, the VNAB lesion, unlike PVN denervation, depleted the median eminence (ME) of both amines (-80%). Concomitantly, the VNAB lesion led to a 97% reduction of the immunoreactive (ir) CRH-41 concentration in the hypophysial portal vessels, associated with a 64% fall in plasma adrenocorticotropic hormone (ACTH), and, in another group, with an 80% inhibition of ether stress-induced ACTH surge. The deletion of CA innervation of the PVN alone reduced irCRH-41 levels in the portal vessels by only 57% and plasma ACTH by 35%. This lesion did not significantly impair stress-induced ACTH release. These results suggest that the CA innervation of the hypothalamus exerts a stimulatory control on CRH-41-secreting neurons not only directly at the perikaryal level but also at other hypothalamic sites of VNAB innervation including peripheral contacts between the terminals of CA and CRH nerves in the external ME.
Adrenocorticotropic Hormone↗
Maturation of the pituitary-adrenal function in rat fetuses.
Plasma adrenocorticotropic hormone (ACTH) and corticosterone were detectable in fetal plasma on day 16 of pregnancy. Thereafter, the levels of both hormones increased steadily in a parallel manner and reached a peak on day 19 of pregnancy. Administration of an antiserum anti-rat corticotropin-releasing factor (CRF) to pregnant rats was followed by a significant decrease in fetal plasma corticosterone as early as day 17. Plasma ACTH measured under the same experimental conditions on day 19 of gestation was also significantly decreased. Similar results have been obtained with fetal plasma collected from adrenalectomized pregnant rats, indicating that the plasma corticosterone decrease in fetuses after immunoneutralization of CRF reflects changes in fetal adrenal secretion and not a diminution of corticosterone transfer from the maternal to the fetal circulation. These results show that endogenous CRF begins to play a physiological role in the regulation of ACTH and corticosterone secretion as early as in 17-day-old fetuses. This effect may occur before the connections between the neurosecretory CRF axons and the hypophysial portal capillaries have been established. Therefore, endogenous CRF may enter the hypophysial portal circulation after intercellular diffusion in hypothalamic tissue.
Adrenocorticotropic Hormone↗
In vitro corticotropin-releasing hormone (CRH) stimulation of adrenocorticotropin release from corticotroph adenoma cells: effect of prolonged exposure to CRH and its interaction with cortisol.
To examine if down-regulation of CRH-induced ACTH release occurs in corticotroph adenoma cells as well as CRH-glucocorticoid interactions in these cells, we established primary cultures of pituitary adenoma cells obtained by transphenoidal surgery from five patients with Cushing's disease. To prevent binding of glucocorticoids by serum proteins, we used a serum-free medium containing insulin, transferrin, selenium, and epidermal growth factor. The latter was found to be essential for both basal and CRH-stimulated ACTH secretion. CRH acutely stimulated, in a dose-dependent manner, ACTH release by all adenomas studied, with an IC50 of 0.5 X 10(-9) mol/L. Prolonged exposure (10 days) to a half-maximal stimulatory concentration of CRH led to continuous stimulation of ACTH secretion. A 4-day incubation with cortisol induced a dose-dependent decrease in both basal and long term CRH-stimulated ACTH release, with no difference in the IC50 (1 X 10(-8) mol/L). These data suggest that long term exposure to CRH does not desensitize corticotroph adenoma cells. Thus, it is unlikely that long-acting analogs of CRH will be useful in the treatment of Cushing's disease. ACTH secretion from corticotroph adenomas is restrained by glucocorticoids; the sensitivity of these cells to the negative effect of glucocorticoids is not modified by long term stimulation with CRH.
Adenoma↗
Characterization of corticotropin-releasing hormone receptors on human pituitary corticotroph adenomas and their correlation with endogenous glucocorticoids.
Specific receptors for CRH were identified in five freshly excised pituitary adenomas causing Cushing's disease. Their kinetic properties and mean affinity constant [1.45 +/- 0.38 (+/- SE) nmol/L] were comparable to the characteristics of rat and monkey anterior pituitary CRH receptors. No correlation was found between the immediate preoperative plasma and urinary cortisol levels and the number of pituitary adenoma CRH receptors, which ranged from 6-96 fmol/mg protein, unlike in rats, in which corticosterone modulates the number of anterior pituitary CRH receptors. The lack of correlation between the concentration of CRH receptors and plasma cortisol levels may reflect the inability of glucocorticoids to down-regulate CRH receptors in these tumors. Thus, corticotroph adenomas are resistant not only to the feedback actions of glucocorticoids on proopiomelanocortin synthesis and secretion but also to their actions on CRH receptors.
Adenoma↗
Corticotrophin-releasing factor immunoreactivity in the hypothalamus of the rat during the perinatal period.
Corticotrophin-releasing factor-41 (CRF-41) immunoreactivity has been measured in hypothalamic extracts of fetal (on days 17, 19 and 21 of gestation), neonatal (1, 2, 3 and 4 weeks of age) and adult rats with a specific radioimmunoassay developed for synthetic rat CRF-41. The hypothalamic content (fmol) and concentration (fmol/mg protein) of immunoreactive CRF-41 gradually increased with age. Chromatography of hypothalamic extracts on Sephadex G-50 Fine showed one single peak of immunoreactive CRF-41 which co-eluted with synthetic rat CRF-41. The retention time of hypothalamic CRF-41 during high-performance liquid chromatography was identical to that of synthetic rat CRF-41 at all stages investigated. These results are consistent with the development of neurones containing CRF-41-like molecules in both the hypothalamus and the median eminence of the fetus, as well as with the hypothalamic control of the cortico-stimulating function of the pituitary gland as early as day 19 of gestation.
Aging↗
Duration of Alphavirus neutralizing antibody in naturally infected birds.
Native birds, mostly passerine species, ecologically associated with Culiseta melanura, the enzootic vector of eastern equine encephalomyelitis and Highlands J viruses in the eastern United States, were examined over a 12-year period in southeastern Massachusetts. These studies concentrated on those individual birds known, by banding returns, to be residents of large wooded swamps where both eastern equine encephalomyelitis and Highlands J viruses were known to be enzootic. Of 8,417 birds sampled, 1,227 (14.6%) were recaptured one or more times (mean 2.7 times). Antibody profiles on individuals nesting or feeding in enzootic areas were determined from serial blood samples drawn from these recaptured birds. The duration of detectable neutralizing antibody in these birds was found to be ephemeral in some species (e.g., black-capped chickadees) and extremely longlasting in others (e.g., gray catbirds, swamp sparrows). The significance of these findings to arbovirus surveillance programs is discussed.
Alphavirus↗
Hospice--an update on the cost of patient care.
This follow-up survey to a study into the cost of providing Hospice in-patient care in 1984 examines in detail the cost profiles of up to 40 well established Hospices in the UK. The results are analysed in order to provide up to date financial and statistical information on the major areas of current Hospice activity.
Costs and Cost Analysis↗
Further studies on the effect of glucose concentrations and other oxidizable substrates upon ionic gradients and in vitro somatostatin release from rat mediobasal hypothalamus.
During in vitro incubation of rat mediobasal hypothalamus (MBH), potassium and sodium gradients were high in the presence of glucose, pyruvate, lactate or the mixture glucose and pyruvate; in the absence of substrate, the ionic gradients were markedly lowered and corresponding somatostatin release from MBH was maximal. The specific effect of glucose on somatostatin release from MBH was tested under normal tissue polarization, i.e. in the presence of pyruvate. Under these more physiological conditions, somatostatin release was submaximal and inversely related to glucose concentrations (within the range 0-7 mM).
Animals↗
Ontogenesis of TRH mRNA in the rat pancreas.
The rapid changes in TRH levels in the rat pancreas during the neonatal period make this organ an interesting model for the study of the regulation of TRH biosynthesis. Pancreatic RNAs were isolated by the guanidinium thiocyanate method and layered onto CsCl cushion. Northern blot preparations were hybridized with 32P labeled TRH cDNA probe. Pancreatic TRH mRNA was first detected in 19-day old fetuses and reached the highest level on day 0, then decreased, being barely detectable 14 days after birth. The neonatal injection of streptozotocin induced a dramatic drop of TRH mRNA levels 24 hours later. This result suggests that the peculiar evolution of TRH level in pancreas is partly due to the evolution of the expression of the TRH gene.
Animals↗
Evidence for basal and stress-induced release of corticotropin releasing factor in the push-pull cannulated median eminence of conscious free-moving rats.
Fourteen adult male rats were successfully implanted in their median eminence with a push-pull cannula perfusing an artificial fluid at a rate of 13 microliters/min, to measure the release of corticotropin releasing factor (rCRF-41) under physiological conditions assessed by baseline plasma adrenocorticotropic hormone (ACTH) levels. In the basal conscious free-moving state, rCRF-41 release displayed a fluctuating pattern, with peaks about every 45 min at a mean value of 9.0 +/- 0.7 pg/15 min sample (n = 42) vs a mean trough value of 4.1 +/- 0.3 pg/sample (n = 44). Ether stress was followed by a striking rise in rCRF-41 release which generally lasted about 45 min and reached mean peak values of 54.3 +/- 3.2 pg/15 min sample (n = 7). These data constitute the first direct measurements of basal and stress-induced CRF releases in conscious unrestrained rats.
Adrenocorticotropic Hormone↗
The enzymatic degradation of polymers in vitro.
Specimens of 14C-labeled poly(ethylene terephthalate), nylon 66, and poly(methyl methacrylate) have been synthesized and exposed, in vitro, to a number of enzyme solutions. Poly(ethylene terephthalate) was found to be affected by esterase and papain, although in different ways, but not by trypsin or chymotrypsin. Nylon 66 was unaffected by esterase but degraded by the other three. Poly(methyl methacrylate) was not affected by any of these enzymes. This indicates that some nominally stable polymers are susceptible to degradation by enzymes under some circumstances. The amount of degradation is small, but could have significant sequelae should it be reproduced in vivo.
Chymotrypsin↗
The biodegradation of poly(ether urethanes).
Explore the source record for details and available documents.
Biodegradation, Environmental↗
A clonal derivative of tunicamycin-resistant Chinese hamster ovary cells with increased N-acetylglucosamine-phosphate transferase activity has altered asparagine-linked glycosylation.
A population of Chinese hamster ovary (CHO) cells resistant to the antibiotic tunicamycin (TM) had previously been isolated (Criscuolo, B.A., and Krag, S.S. (1982) J. Cell Biol. 94:586-591) by a stepwise selection procedure using progressive increments of TM added to the medium. TM inhibits asparagine-linked glycoprotein biosynthesis by blocking the transfer of N-acetylglucosamine-1-phosphate from the sugar nucleotide UDP-N-acetylglucosamine to the isoprenoid lipid carrier, dolichyl phosphate. Four clonal derivatives were isolated from the TM-resistant population in the presence of 27 micrograms TM/ml and were found to overproduce the N-acetylglucosamine-phosphate transferase activity to the same extent (approximately 15-fold compared to wild-type cells). One of these clones, 3E11, was greater than 550-fold more resistant to TM than wild-type cells. The resistance phenotype remained during at least 2.5 months of growth in the absence of TM. 3E11 cells exhibited chromosomal translocations, but no homogeneously staining regions (HSR) or double minute chromosomes. The N-acetylglucosamine-phosphate transferase activity in 3E11 cells was membrane-associated and was inhibited by TM. A 140,000-dalton membrane protein and at least four other membrane proteins were enriched in 3E11 cells. Mannosylphosphoryldolichol synthase and glucosylphosphoryldolichol synthase activities were not elevated in membranes prepared from 3E11 cells. Asparagine-linked glycosylation was altered such that 3E11 cells synthesized primarily a truncated oligosaccharide, Man5GlcNAc2, perhaps due to the reduced amount of mannosylphosphoryldolichol relative to wild-type cells.
Animals↗
Growth of exocrine acinar cells on a reconstituted basement membrane gel.
Methods have been developed for culturing a dividing population of morphologically differentiated rat parotid, lacrimal, and pancreatic acinar cells in vitro. Isolated acinar cells were plated onto tissue culture dishes coated with a three-dimensional, reconstituted basement membrane gel. After attachment in Ham's nutrient mixture F12, the cells were cultured at 35 degrees C in F12 supplemented with 10% heat inactivated rat serum, epidermal growth factor, dexamethasone, insulin, transferrin, selenium, putrescine, reduced glutathione, ascorbate, penicillin, streptomycin, and the appropriate secretagogue. Under these conditions, the cells attached rapidly and DNA synthesis was initiated within 2 to 3 d. Although the cells flattened on the substratum, they continued to maintain their differentiated morphology. The cells contained secretory granules, and the secretory enzymes peroxidase and amylase could be detected. The use of a reconstituted basement membrane gel proved critical for the attachment and growth of exocrine acinar cells.
Animals↗