Chemical and biological characterization of corticotropin releasing factor.
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Adrenocorticotropic Hormone↗
Biomedical subjects
M R Brown
Publications and source records attributed to M R Brown.
A high protein, low calorie liquid diet in the treatment of very obese adolescents: long-term effect on lean body mass.
The use of Optifast-70, a high protein liquid diet, when used in the range of 500 to 700 cal over 5 months in very obese adolescents, was associated with weight loss of 20 to 25% of initial weight of which 70 to 75% of the loss was due to fat. No significant side effects were noted. Twenty-four hour electrocardiographic monitoring showed no significant changes, and linear growth continued. Lean body mass loss was 36% of the weight lost during the first 5 wks, but was only 10% of the weight lost during the next few months. Two adolescent males had negative phosphorus and nitrogen balances over the first 4 wk, implying that males may have slightly higher phosphorus, nitrogen, and calorie requirements.
Adolescent↗
Hepatic abscess as a complication of Crohn's disease.
A 17-year-old male with Crohn's disease presented with persistent fever and right upper quadrant tenderness. Ultrasonography and abdominal computerized axial tomography (CAT scan) showed two large loculated abscess cavities in the right lobe of the liver. Surgical drainage and antibiotic therapy led to resolution of both cavities over a 5-month period. Unlike six previously reported patients, our patient had no evidence of pylephlebitis or mesenteric abscess formation at surgery. We speculate that his abscesses arose through seeding of mesenteric vessels and portal bacteremia.
Adolescent↗
Isolation and characterization of the outer and cytoplasmic membranes of Pseudomonas cepacia.
A method is described for the separation of the outer membrane (OM) from the cytoplasmic membrane (CM) of Pseudomonas cepacia grown in nutrient broth and in chemically defined media under different nutrient depletions. The method is particularly valuable since it is effective when applied to stationary phase cells. Enzyme activities indicated that the contamination of the OM with the CM was less than 5%. The OM protein profile of magnesium-depleted cells was much simpler than that of the iron-depleted and nutrient broth grown cells. The apparent molecular weights of the OM proteins of magnesium-depleted cells were: 40 000, 36 000, 24 500 and 14 500. Iron depletion induced the synthesis of an OM protein with apparent molecular weight of 66 000. The OM proteins with apparent molecular weights of 40 000, 36 000 and 24 500 were heat-modifiable and the 24 500 dalton protein was found also to be affected by the presence of 2-mercaptoethanol. The OM consisted of 50% protein and 20% phospholipid and the rest was probably LPS while the CM consisted of 80% phospholipid and 20% protein. The major phospholipid in both membranes was phosphatidylethanolamine with a smaller amount of phosphatidylglycerol and a trace amount of phosphatidylcholine; the OM contained more phosphatidylethanolamine than the CM.
Cell Fractionation↗
Disruptive effects of tris and sodium lauroyl sarcosinate on the outer membrane of Pseudomonas cepacia shown by fluorescent probes.
The disruptive effects of Tris buffer and sodium lauroyl sarcosinate (Sarkosyl) on the outer membrane (OM) of Pseudomonas cepacia were investigated with several fluorescent probes. Tris increased the permeability of the OM to 6-anilino-l-naphthalenesulphonic acid and 2-p-toluidinylnaphthalene-6-sulphonate. The degree of damage to the OM was enhanced when the pH was decreased 3-(N-morpholino)propanesulphonic acid buffer had a small but significant effect at acid pH, while citrate/phosphate buffer showed insignificant effects. Sarkosyl released 3,3'-dipentyloxacarbocyanine iodide (CC5) from CC5-labelled OM or whole cells and altered OM fluidity as studied by fluorescence polarization.
Anilino Naphthalenesulfonates↗
Effect of nutrient depletion on sensitivity of Pseudomonas cepacia to phagocytosis and serum bactericidal activity at different temperatures.
Pseudomonas cepacia grown under different specific nutrient depletions in batch culture showed varying degrees of sensitivity to engulfment and killing by human polymorphonuclear leukocytes (PMN) and to killing by human serum. Resistance to killing by the combined action of PMN and serum in while blood was found to increase in the following order of depletions: glucose less than iron less than sulphate less than phosphate or ammonium less than magnesium. There was also an increase in resistance to killing by whole blood with decrease in temperature, except that carbon-depleted cells remained very sensitive irrespective of temperature. Cells in the exponential phase of growth also showed a consistent increase in resistance as the temperature was decreased. Similar, but smaller effects were observed with oxygen-depleted cells. The increase in killing by whole blood as the phagocytic temperature was raised correlated with an increase in the number of bacteria ingested per PMN. A pattern of serum sensitivity was observed with cells grown under different nutrient depletions similar to that for whole blood. But in all cases whole blood was 6 to 10 times more effective than serum alone in killing the cells at 37 degrees C.
Anaerobiosis↗
The role of the O and K antigens in determining the resistance of Klebsiella aerogenes to serum killing and phagocytosis.
The presence of both K and O antigens of Klebsiella aerogenes was found necessary to protect the organism from either complement-mediated serum killing or phagocytosis in the absence of specific antisera. Optimal phagocytic ingestion of K. aerogenes NCTC 5055 could be achieved in the presence of either anti-K or anti-O sera or to a much smaller extent in antisera raised against a rough unencapsulated mutant (M10B) derived from NCTC 5055. Anti-O sera failed to opsonize a clinical klebsiella isolate (DL1) possessing immunologically identical lipopolysaccharide, but did so when the amount of capsule was physically reduced. The serum sensitivity of the encapsulated strains was unaffected by the addition of specific antisera. Fresh serum was bacteriostatic for an unencapsulated smooth mutant (M10) derived from NCTC 5055. This bacteriostatic effect was reduced by heat-inactivation of the serum or by the addition of anti-O serum. M10 was rendered sensitive to the bactericidal action of serum in the presence of antisera raised against M10B or after chelation with MgEGTA to isolate alternative complement pathway activity. The rough unencapsulated mutant (M10B) was rapidly killed by fresh serum, an effect which could be delayed by chelation with MgEGTA. The serum sensitivity of M10B was unaffected by the presence of anti-M10B sera. Thus, the O antigen, unlike the K antigen, of these klebsiella strains is not antiphagocytic but it does confer some protection against the rapid bactericidal activity of serum complement.
Antigens↗
Characterization of the peptide and sensory neurotoxic effects of capsaicin in the guinea pig.
The effects of capsaicin, the major pungent ingredient of hot peppers, were assessed on sensory neuron neuropeptide levels and on sensory function in the adult guinea pig. Systemic doses of capsaicin as low as 2.5 mg/kg depleted substance P (SP) in dorsal roots plus ganglia (DRG) whereas a 10-mg/kg dose depleted the peptide maximally in DRG and in the dorsal spinal cord. High doses of capsaicin had no consistent effects on levels of cholecystokinin (CCK), vasoactive intestinal polypeptide, or somatostatin, although a transient decrease in CCK levels was observed 4 days after dosing. A single 5-mg/kg dose of capsaicin rendered animals completely insensitive to chemical irritation of the cornea without affecting sensitivity to noxious heat. Higher doses of capsaicin produced a marked insensitivity to nociceptive and non-nociceptive heat as well as to chemical irritation without affecting other sensory modalities. The SP depletion and sensory deficits produced by a single 50-mg/kg dose of capsaicin were still evident 10 weeks later. The pattern of selectivity of the sensory deficits produced by capsaicin differed from that produced by morphine which was active against all forms of nociceptive stimuli. The results indicate that in the guinea pig capsaicin is potent at producing a unique, long-lasting syndrome of peripheral sensory deficits that may result from an effect of the agent on SP-containing primary afferent neurons.
Animals↗
Parasites of domestic and wild animals in South Africa. XVI. Helminth and arthropod parasites of blue and black wildebeest (Connochaetes taurinus and Connochaetes gnou).
Fifty-five blue wildebeest ( Connochaetes taurinus ) were shot for parasite recovery at approximately monthly intervals during a period of 13 months in the Kruger National Park. Thirteen nematode species, 4 cestode species, 1 trematode, the larvae of 5 oestrid flies, 3 lice species, 7 ixodid tick species, 1 mite species and the nymphae of a pentastomid were recovered. The seasonal prevalence of 8 nematodes, 2 cestodes, the larvae of 4 oestrid flies, 2 lice and 4 ixodid tick species was determined. The endo- and ectoparasite burdens of 7 black wildebeest ( Connochaetes gnou ) shot in the Golden Gate Highlands Park in the Orange Free State and 3 shot in the Rietvlei Reserve in the Transvaal were determined. These animals harboured 4 nematode species, 1 cestode, the larvae of 5 oestrid fly species, 2 lice species, 4 ixodid tick species and a mite species.
Animals↗
Body weight and its effect on immunoreactive parathyroid hormone levels.
Immunoreactive parathyroid hormone (iPTH) levels were measured in 12 obese subjects (140-272% ideal body weight) and 10 normal lean volunteers (93-100% ideal body weight). iPTH values were not significantly different in the two groups and tubular maximum phosphate reabsorption (TmP) was comparable in lean subjects and the 4 obese patients tested. 4 obese subjects were evaluated after an average of 6.7% body weight loss, and neither iPTH levels nor TmP were affected. The data indicate that the biological effects of PTH are not enhanced in the massively obese.
Absorption↗
Bombesin and somatostatin related peptides: effects on oxygen consumption.
Bombesin and the somatostatin analog, desAA-[D-Trp8]-somatostatin (ODT8-SS), act within the central nervous system to alter animals' oxygen consumption (VO2) in a manner consistent with the observed effects of these peptides on temperature regulation. Bombesin given intracerebroventricularly (i.c.v.) to rats at cold ambient temperatures prevents elevation of VO2 but does not lower VO2 below the values observed at thermoneutrality. ODT8-SS given i.c.v. increases VO2 of animals at an ambient temperature of 20 degrees C and prevents bombesin inhibition of VO2 at low ambient temperatures. Thus, bombesin inhibits VO2 induced by cold and results in hypothermia, ODT8-SS prevents bombesin-induced inhibition of VO2 and bombesin-induced hypothermia and, ODT8-SS increases VO2 and produces hyperthermia in animals at thermoneutral temperatures.
Animals↗
Corticotropin-releasing factor: effects on the sympathetic nervous system and oxygen consumption.
Corticotropin-releasing factor administered intracerebroventricularly produces prolonged elevation of plasma concentration of epinephrine, norepinephrine and glucose. These hormonal changes are associated with an increase in motor activity and oxygen consumption. No change in body temperature is observed. CRF produces changes in animal physiology that are similar to those observed in response to stress.
Animals↗
Comparison of the biologic actions of corticotropin-releasing factor and sauvagine.
Corticotropin-releasing factor (CRF), a peptide isolated from ovine hypothalamus, and sauvagine, a peptide isolated from frog skin, share significant structural homology and elicit a number of similar biological responses. CRF is more potent than sauvagine in stimulating pituitary ACTH secretion. Sauvagine, however, is 5-10 times more potent than CRF to act within the brain to increase plasma levels of catecholamines and glucose and to elevate mean arterial pressure. Sauvagine is likewise more potent than CRF to act outside the brain to increase superior mesenteric artery flow and plasma glucose concentrations and to decrease mean arterial pressure. CRF and sauvagine produce important effects representative of biologically active peptides.
Adrenocorticotropic Hormone↗
Acquired distal aganglionosis of the colon.
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Biopsy↗
Effect of duration of exposure on diarrhea due to enterotoxigenic Escherichia coli in travelers from the United States to Mexico.
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Adult↗
Use of psyllium in the management of chronic nonspecific diarrhea of childhood.
The etiology and treatment of chronic nonspecific diarrhea of childhood is still poorly understood. We evaluated 23 children with this disorder in whom other etiologies of chronic diarrhea had been ruled out. The children were treated first with an unrestricted diet for 1 week, and if no response was obtained they were then treated with psyllium bulk agents for 2 weeks (1 tablespoon b.i.d.). Eighty-seven percent of the patients responded to therapy. Seven patients responded to an unrestricted diet only, and 13 responded to psyllium. Only three patients (13%) did not respond. Most children were on a restricted diet at presentation, but the amount of dietary fat intake did not correlate with the response, contrary to other reports. Treatment with normalization of the diet and psyllium bulk agents seems to be an effective mode of therapy for chronic nonspecific diarrhea of childhood.
Child, Preschool↗
Colonial variants of proteus species: their growth requirements, biochemical characters and resistance to antibacterial agents.
Stable small-colony variants of Proteus species were isolated and characterised. They differed from typical organisms in their morphology, biochemical properties and drug resistance. They were found most frequently in culture media of low osmolarity. Their growth rate was depressed at high concentrations of salts, which had only a small effect on typical organisms. This may be important in the routine isolation of proteus spp. and in testing of disinfectants.
Anti-Bacterial Agents↗
Evaluation of glycine as an inactivator of glutaraldehyde.
Glycine was evaluated as an inactivator of the sporicidal activity of glutaraldehyde. Spores from glucose depleted cultures of Bacillus stearothermophilus grown in a chemically defined medium were used. When glycine is used as an inactivator of glutaraldehyde, it lowers the pH value of the solution. Glycine 1% failed to inactivate 0.5% or higher concentrations of alkaline glutaraldehyde in sporicidal studies. If viable counts cannot be performed within the first hour after inactivation, the concentration of glycine should be at least 2% to inactivate effectively 2% alkaline glutaraldehyde.
Aldehydes↗