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D Gerber

Publications and source records attributed to D Gerber.

At least 55 records · Page 3Linked to original sources
PubMed1996

Increased pituitary activation following metyrapone administration in post-traumatic stress disorder.

Our previous findings have demonstrated that individuals with post-traumatic stress disorder (PTSD) show lower basal cortisol levels, a larger number of lymphocyte glucocorticoid receptors, and an enhanced suppression of cortisol following the administration of dexamethasone compared to normals and patients with major depression. We have previously suggested that these alterations reflect an enhanced negative feedback inhibition of the hypothalamic-pituitary-adrenal (HPA) axis in PTSD. However, in the absence of direct knowledge of pituitary capability in this disorder, it has been equally likely that the alterations observed reflected either pituitary or adrenal insufficiency. In the present study, we examined ACTH release from the pituitary gland in PTSD following the administration of metyrapone. Metyrapone resulted in a significantly greater increase of ACTH and 11-deoxycortisol in combat veterans with PTSD (n = 11) compared with normal male volunteers (n = 8). When seen in the context of other abnormalities observed in PTSD, the present demonstration of increased pituitary activity in the absence of negative feedback provides unequivocal support for the hypothesis of enhanced negative feedback.

Adrenocorticotropic Hormone↗
PubMed1996

Rearrangement and expression of Vzeta1, Vzeta2 and Vzeta3 TCR zeta genes in C57BL/6 mice.

We have recently described a mAb (2.11) that recognizes the Vgamma1-Jgamma4-Cgamma4 chain. With this mAb and an anti-delta mAb we separated gammadelta+ 2.11(+) and gammadelta+ 2.11(-) intraepithelial lymphocytes (i-IEL) by FACS. Transcripts of rearranged TCR Vgamma1 and Vdelta2 genes in both i-IEL populations were analyzed by PCR followed by sequence analysis of cDNA spanning the junction of variable (V) and joining (J) genes. Roughly the same number of Vgamma1 and Vgamma2 transcripts were found in the 2.11(+) population while >90% of the transcripts in the 2.11(-)population contained a Vgamma gene sequence. Furthermore, gamma transcripts in the 2.11+ population were functional, while only 30-40% of the Vgamma transcripts in either population contained an in-frame sequence. The observed frequency of transcripts is what would be expected from cell populations that have not gone through cellular selection mediated by the RCR. Expression of Vgamma mRNA in RCRalphabeta and TCRgammadelta thymocytes was studied by a technique that analyzed populations of transcripts of rearranged genes. In both T cell population similar levels of Vgamma transcripts were found and about two out of three transcripts were out-of-frame. During the cloning and sequence analysis, we indentified a clone that expresses the Vgamma segment rearranged to the Jgamma3-Cgamma region in C57BL/6 mice. Together with the PCR cloning and sequencing of the complete Cgamma region in C57BL/6 mice these data demonstrate that the Jgamma-Cgamma gene is functional in this strain. Taken together, these studies revealed that: (i) cells expressing the Vgamma1 chain are an important subset of the gammadelta i-IEL population and that they show extensive junctional diversity; (ii) there is no correlation between expression of in-frame Vgamma transcripts and expression of Vgamma2 chains at the cell surface; and (iii) cells expressing the Vgamma3 chain might be a minor subset of the gammadelta T cell population in C57BL/6 mice.

Amino Acid Sequence↗
PubMed1995

Ontogenic development and tissue distribution of V gamma 1-expressing gamma/delta T lymphocytes in normal mice.

A hamster monoclonal antibody (mAb) recognizing an epitope in the V gamma 1-J gamma 4-C gamma 4 chain of the gamma/delta T cell receptor has been generated. Using this mAb, we have quantitated the occurrence of V gamma 1-bearing gamma/delta T cells in the developing thymus and in the lymphoid organs and several epithelia of adult mice. The V gamma 1-expressing cells constitute a minor gamma/delta T cell subpopulation during fetal and early postnatal life, but they constitute a major population of gamma/delta T cells in the thymus and in the peripheral lymphoid organs in adult mice. In addition, we found that V gamma 1-bearing cells comprise a large proportion (15-60%) of the gamma/delta T cells present in the intestinal epithelium (i-IEL) in all strains of mice tested. V gamma 1+ i-IEL are present in athymic (nude) mice and in antigen-free mice, demonstrating that they can develop extrathymically and that their presence in the intestinal epithelium is independent of the antigenic load of the gut. Our results show that V gamma 1-bearing lymphocytes account for the largest population of gamma/delta T cells in the mouse. This population includes a thymus-dependent component that homes to the secondary lymphoid organs and a thymus-independent component that constitutes a major fraction of the gamma/delta i-IELs.

Animals↗
PubMed1995

Tonegawa defended.

Explore the source record for details and available documents.

Competitive Behavior↗
PubMed1995

Interactions of polyamines with Mg(2+)-sensitive macroelectrodes and Mg2+ buffers.

The polyamines spermine, spermidine and putrescine interact with Mg(2+)-sensitive macroelectrodes based on the neutral carrier ETH 7025; the interaction in decreasing order being spermine, spermidine and putrescine. The effect is small and dependent on the ionized magnesium concentration ([Mg2+]free), only resulting in a significant increase in the measured [Mg2+]free with spermine and spermidine at [Mg2+]free less than 0.5 mM. The polyamines compete with Mg2+ for common binding sites on Mg2+ buffers such as ATP, ADP and citrate, releasing bound Mg2+ and increasing the [Mg2+]free. This effect is most prominent with Mg ATP and the action of the polyamines in decreasing order is spermine, spermidine and putrescine. Increases in polyamines which occur in cell proliferation and cancer could thus secondarily increase the [Mg2+]free resulting in an activation of Mg(2+)-dependent metabolic pathways.

Adenosine Diphosphate↗
PubMed1994

Influence of age, breed, and stage of pregnancy on hepatic ultrasonographic findings in cows.

Influence of age, breed, and stage of pregnancy on hepatic ultrasonographic findings of cows was determined. In addition, the relation between body weight, height at the withers, milk production, and the measurements determined via ultrasonography was investigated. The liver of 186 cows was examined ultrasonographically. The cows comprised Swiss Braunvieh, Simmental, and Holstein breeds, and age ranged from 2.5 to 11.5 years. The ultrasonographic findings of the liver, gallbladder, caudal vena cava, and portal vein were described, and the position, size, thickness, and distal angle of the liver were determined. In addition, the position and diameter of the caudal vena cava and portal vein were determined. There was no significant difference between any of the variables determined and breed or age. Therefore, measurements for the 3 breeds and for the various ages were summarized into 1 group. There were significant correlations between body weight, milk production, and size and thickness of the liver. In 3 pregnant cows, the liver was examined ultrasonographically 8 times during the course of pregnancy. Positive correlation was detected between stage of pregnancy and diameter of the caudal vena cava. There was a negative correlation between stage of pregnancy and diameter of the portal vein. In 23 cows, the ultrasonographically determined measurements of the liver were compared with those determined at slaughter. Weight of the liver correlated well to thickness of the liver determined via ultrasonography.

Aging↗
PubMed1992

Ultrasonography of the urinary tract of female sheep.

We determined the position, dimensions, and structure of the kidneys, ureters, bladder, and urethra of 62 female sheep by use of ultrasonography. A 5.0-MHz convex transducer was placed over the right flank to examine the kidneys, and a 5.0 MHz-linear transducer was used to examine the bladder and urethra transrectally. All examinations were performed on sheep in standing position. The left kidney was 7.1 to 8.9 cm long, 3.4 to 5.5 cm wide, and 3.3 to 4.7 cm deep. Diameter of the parenchyma and renal sinus of the left kidney ranged between 1.1 and 1.9 cm and 1.1 and 2.0 cm, respectively. Circumference of the medullary pyramids varied between 2.1 and 3.3 cm. Similar ultrasonographic measurements were obtained for the right kidney. The diameter of the bladder varied between 0.3 and 6.9 cm in 96.8% of the sheep. The diameter of the bladder could not be determined in 32% of the sheep because it was > 10 cm, and, therefore, was beyond the penetration depth of the scanner. The only part of the urethra that could be ultrasonographically visualized was the internal urethral orifice. It had diameter between 0.1 and 0.2 cm. The ureters could not be ultrasonographically visualized in any of the sheep examined. The urinary tract of 8 sheep was examined 10 times within 2 weeks to examine whether measurements were reproducible. The interassay variation coefficient determined ranged from 3.1 to 31.8%, although for most variables, it ranged between 5 and 11%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1992

Percutaneous ultrasound-guided cholecystocentesis in cows.

A method was developed for percutaneous ultrasound-guided cholecystocentesis in cattle. The procedure was performed on the right side in the 9th, 10th, or 11th intercostal space of 30 cows. Of the 30 cows, 20 were slaughtered 24 hours after cholecystocentesis and the remaining 10 cows were slaughtered after a 10-day observation period. Changes in the peritoneum and gallbladder wall, observed at slaughter, were minimal. During the 10-day observation period, general behavior, attitude, and appetite of the 10 cows were normal. A transient, slight increase in rectal temperature was observed in 6 cows at 4, 5, or 8 days after cholecystocentesis. Total and differential WBC counts and total protein and fibrinogen concentrations, determined daily, were all within normal ranges. Bile samples from 20 cows were examined microscopically and biochemically. Fasciola hepatica and Dicrocoelium dendriticum eggs were observed in bile from 7 and 12 cows, respectively. Fecal examination revealed F hepatica eggs in 4 cows; D dendriticum eggs were not identified in any of the fecal samples. In 1 cow, F hepatica eggs were observed in the feces, but not in the bile. Bile acids concentration in bile varied from 12.5 to 68.5 mmol/L (mean +/- SD, 45.3 +/- 3.05 mmol/L) and in serum from 3.8 to 281.0 mumol/L (41.6 +/- 17.24 mumol/L). Negative correlation was obtained between bile acids concentration in bile and that in serum (r = -0.60, P less than 0.01). It was concluded that percutaneous ultrasound-guided cholecystocentesis in cows is a safe procedure and that microscopic and biochemical examinations of obtained bile can be useful diagnostic aids.

Animals↗
PubMed1992

Ultrasonographic findings in a cow with ascites due to thrombosis of the caudal vena cava.

This case report describes a three-year-old Swiss Braunvieh cow with ascites due to thrombosis of the caudal vena cava. Ultrasonography verified the ascites and revealed dilatation of the abdominal portion of the caudal vena cava (4.8 cm). It was presumed that the caudal vena cava was occluded by a thrombus or by perivenous compression cranial to the dilatation. Post mortem findings included: a massive accumulation of fluid in the abdominal cavity; a 15 cm long thrombus in the subphrenic region of the caudal vena cava; multiple pulmonary abscesses; severe thrombosis of the pulmonary vasculature; hepatic congestion; oedematous abomasal folds; and severe thrombophlebitis of the left jugular vein and both udder veins, due to poor intravenous injection technique. Ascites caused by thrombosis of the caudal vena cava is rare because collateral routes of venous return, including the udder veins, are usually established. It was therefore concluded that the ascites was attributable to bilateral thrombosis of the udder veins.

Animals↗
PubMed1991

Bleeding abomasal ulcers in dairy cows.

The clinical signs and changes in blood and rumen fluid, and the results of therapy are described in 35 cows suffering from bleeding abomasal ulcer. The most important pathological findings were moderate to severe anaemia with pale mucous membranes and tachycardia, dark coloured to black faeces, a disturbed general condition and anorexia. Two of the cows were slaughtered immediately. The others were treated by the transfusion of several litres of blood and the intravenous administration of a solution containing sodium chloride and glucose and other drugs such as calcium solution, vitamin K, vitamin C and metoclopramide. Two animals died in spite of the treatment and three had to be slaughtered because of the deterioration in their condition. The other 28 cows recovered within a few days and their general condition, appetite and defecation returned to normal.

Abomasum↗
PubMed1990

Novel hybrid maturases in unstable pseudorevertants of maturaseless mutants of yeast mitochondrial DNA.

Unstable pseudorevertants of mitochondrial mutants of Saccharomyces cerevisiae lacking the maturase function encoded by the fourth intron of the cytochrome b gene (bI4) were isolated. They were found to be heteroplasmic cells owing their regained ability to respire (and grow on glycerol medium) to the presence of a rearranged (rho-) mtDNA that contains an in-frame fusion of the reading frames of the group I introns bI4 and intron 4 alpha of the coxl gene encoding subunit I of cytochrome c oxidase (aI4 alpha). The products of those gene fusions suppress the bI4 maturase deficiency still present in those heteroplasmic cells. Similar heteroplasmic pseudorevertants of a group II maturaseless mutant of the first intron of the coxI gene were characterized; they result from partial deletion of the coxI gene that fuses the reading frames of introns 1 and 2. These heteroplasms provide independent support for the existence of RNA maturases encoded by group I and group II introns. Also, since the petite/mit- heteroplasms arise spontaneously at very high frequencies they provide a system that can be used to obtain mutants unable to form or maintain heteroplasmic cells.

Base Sequence↗
PubMed1989

Changes in the Activity of the Chloroplastic and Cytosolic Forms of Dihydroxyacetone Phosphate Reductase during Maturation of Leaves.

Young or mature rosette leaves from spinach (Spinacia oleracea L.) plants growing in the field, in the greenhouse, or in a growth chamber under a regimen of 8 hours light and 16 hours dark contained 15 to 50 nanomoles per minute per gram wet weight of NADH:dihydroxyacetone phosphate reductase activity. Of this activity, 75 to 87% was the chloroplastic isoform and 25 to 13% was the cytosolic form. When plants were induced to senesce, as measured by stem elongation and flowering, the percentage of the two reductase isoforms in rosette or stem leaves changed to about 12% as the chloroplastic and 88% as the cytosolic isoform. The change in enzyme activity of the rosette leaves occurred within 3 days, before phenotypic changes were observed. Likewise, when plants senesced in continuous darkness, the percentage of chloroplastic to cytosolic reductase changed from 80:20% to 25:75% after 62 hours before changes in total protein or chlorophyll occurred. The ratio of activities did not change in the first 16 hours of darkness or overnight. In each case the change in ratio resulted from about a 75% decrease in activity of the chloroplastic isoform and up to 14-fold increase in cytosolic isoform. In spinach leaves purchased at a local market primarily only the cytosolic isoform remained. When plants were returned to normal day-nights, after 62 hours in continuous darkness, the activity of the chloroplastic isoform increased, but not to control levels after 3 days, while the cytosolic enzyme decreased within 1 day to normal day-night values. Changes in activity were not due to changes during in vitro assays in activation by thioredoxin for the chloroplastic isoform or fructose 2,6-phosphate for the cytosolic isoform.

Journal Article↗
PubMed1988

Isolation of dihydroxyacetone phosphate reductase from dunaliella chloroplasts and comparison with isozymes from spinach leaves.

A dihydroxyacetone phosphate (DHAP) reductase has been isolated in 50% yield from Dunaliella tertiolecta by rapid chromatography on diethylaminoethyl cellulose. The activity was located in the chloroplasts. The enzyme was cold labile, but if stored with 2 molar glycerol, most of the activity was restored at 30 degrees C after 20 minutes. The spinach (Spinacia oleracea L.) reductase isoforms were not activated by heat treatment. Whereas the spinach chloroplast DHAP reductase isoform was stimulated by leaf thioredoxin, the enzyme from Dunaliella was stimulated by reduced Escherichia coli thioredoxin. The reductase from Dunaliella was insensitive to surfactants, whereas the higher plant reductases were completely inhibited by traces of detergents. The partially purified, cold-inactivated reductase from Dunaliella was reactivated and stimulated by 25 millimolar Mg(2+) or by 250 millimolar salts, such as NaCl or KCl, which inhibited the spinach chloroplast enzyme. Phosphate at 3 to 10 millimolar severely inhibited the algal enzyme, whereas phosphate stimulated the isoform in spinach chloroplasts. Phosphate inhibition of the algal reductase was partially reversed by the addition of NaCl or MgCl(2) and totally by both. In the presence of 10 millimolar phosphate, 25 millimolar MgCl(2), and 100 millimolar NaCl, reduced thioredoxin causes a further twofold stimulation of the algal enzyme. The Dunaliella reductase utilized either NADH or NADPH with the same pH maximum at about 7.0. The apparent K(m) (NADH) was 74 micromolar and K(m) (NADPH) was 81 micromolar. Apparent V(max) was 1100 mumoles DHAP reduced per hour per milligram chlorophyll for NADH, but due to NADH inhibition highest measured values were 350 to 400. The DHAP reductase from spinach chloroplasts exhibited little activity with NADPH above pH 7.0. Thus, the spinach chloroplast enzyme appears to use NADH in vivo, whereas the chloroplast enzyme from Dunaliella or the cytosolic isozyme from spinach may utilize either nucleotide.

Journal Article↗
PubMed1987

Predictive value of clinical and exercise variables for detection of coronary artery disease in men with diabetes mellitus.

Sixty-eight men with diabetes mellitus (mean age 53 +/- 10 years) and no symptoms of cardiac dysfunction enrolled in a long-range study for detection of latent coronary artery disease. The testing included maximal treadmill stress with thallium-201 scintigraphy and echocardiography. Radionuclide angiography was available in 35 men (52%), and 24 (35%) had gated scanning with exercise. Of the 68 patients, 14 (21%) had a mild (9 patients) or moderate (5 patients) decrease in ejection fraction on radionuclide angiography, echocardiography or both. Fifty-two men agreed to remain in the study and have been followed for 12 to 18 months (mean 41 +/- 19). Ten coronary events have occurred. Four of the men died (2 suddenly) and 6 have angina pectoris. Three patients have had vascular complications. Of the clinical and exercise variables studied, exercise duration effectively predicted an adverse outcome, while the odds ratio in favor of a coronary event increased by 36 times in those with thallium-201 defects and 7 times in those with ST-segment changes on exercise. Radionuclide angiographic responses during exercise were abnormal in 5 of 6 patients with events, but were also abnormal in 12 of 29 men (41%) who did not have coronary artery disease. Clinical variables such as blood pressure, cholesterol level and family history were not predictive of outcome, nor was maximal heart rate during exercise. Thus, diabetic mean who can exercise for 440 seconds on a treadmill using a bruce protocol are at low risk of a coronary event.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1987

Adverse reactions of piroxicam.

During the approximately five years (1981-86) that piroxicam has been available in South Africa, the Medicines Safety Centre has received 31 reports of adverse reactions associated with this drug. Among these are two reactions not previously recorded in the literature, paresthesia and hair loss. This article records drug events associated with piroxicam worldwide and tabulates those received by the Centre.

Adult↗