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Biomedical subjects

J L Peters

Publications and source records attributed to J L Peters.

At least 73 records · Page 4Linked to original sources
PubMed1992

Haloperidol induced CSF protein variations in schizophrenic patients: as studied by two-dimensional electrophoresis.

High resolution two-dimensional electrophoresis of cerebrospinal fluid (CSF) from 10 schizophrenic patients demonstrated a 21% average difference in the number of proteins which could be detected in patients undergoing haloperidol therapy when compared with CSF from the same patients after withdrawal from neuroleptic treatment. Proteins affected were trace proteins, as we found no significant variation in either the total CSF protein content or the integrated protein density on each electrophoretic gel. Three mechanisms which might account for these observations are: (1) a small change in liver protein synthesis or degradation would have little if any visible effect on the concentration of major blood or CSF proteins, such as albumin, but it could significantly alter trace proteins, such as alpha 2-haptoglobin, since their concentrations are orders of magnitude less than that of the major proteins, (2) haloperidol might alter the blood-CSF protein filtration system which could affect the visibility of the trace proteins, and (3) proteins synthesized in the Central Nervous System (CNS) or enhanced in the CSF could be differentially affected by haloperidol. While additional research will be required to determine the basis for the effects of haloperidol on CSF proteins, the current studies provide information which may be helpful in delineating disease specific protein alterations from those induced by drug therapy.

Adult↗
PubMed1990

Effect of naloxone on the secretion of LH in infantile and prepubertal Holstein bull calves.

Administration of naloxone (100 mg i.v.; approximately 1.21 mg/kg body weight0.75) to 10 intact calves (24 weeks of age) caused an acute release of LH that was similar in amplitude and duration to spontaneous discharges of LH that occur at the same age. The naloxone-induced release of LH was abolished in 9/10 calves (intact and castrated) treated with oestradiol-17 beta. To determine the ontogeny of opioid control of secretion of LH, 12 calves were randomly assigned to receive saline or naloxone (1.21 mg/kg body weight0.75, i.v.) at 3, 5, 7, 9, 11, 13, 17 and 21 weeks of age. At each age, blood was collected at 10-min intervals for 4 h and saline or naloxone was administered (i.v.) after collection of the 120-min sample. Before administration of naloxone, plasma LH values increased with age (P less than 0.01) but did not differ between the control and naloxone groups (age x treatment, P greater than 0.05). Administration of naloxone caused concentrations of plasma LH to increase at 3, 11, 13, 17 and 21 weeks of age (treatment x time, P less than 0.001). Concentrations of LH (saline vs naloxone, ng/ml) reached a maximum within 20 min after treatment at Weeks 3 (0.3 vs 1.2), 11 (0.6 vs 2.6), 13 (0.6 vs 3.7), 17 (1.1 vs 2.6), and within 40 min after treatment at Week 21 (1.0 vs 3.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1989

Clonidine treatment of schizophrenia: can we predict treatment response?

Four out of 13 drug-free relapsed schizophrenic patients improved with double-blind clonidine treatment. All responders were paranoid schizophrenic patients. Pretreatment growth hormone (GH) response to the clonidine challenge test (CCT) correlated significantly with clonidine treatment improvement in psychosis, anxiety, and negative symptom ratings. Spontaneous GH peaks following placebo correlated significantly with the behavioral change with clonidine treatment. Our data suggest that patients with normal or high alpha 2-receptor activity and "normal" cerebrospinal fluid (CSF) norepinephrine (NE) are likely to respond to clonidine treatment. Patients with either high or low CSF NE levels did not respond to clonidine treatment. CSF NE and 3-methoxy-4-hydroxyphenylglycol (MHPG) decreased significantly with clonidine treatment. Changes in CSF NE and MHPG did not correlate significantly with improvement in psychosis, but they correlated with changes in other behaviors.

Adult↗
PubMed1989

Alteration of Extracellular Enzymes in Pinto Bean Leaves upon Exposure to Air Pollutants, Ozone and Sulfur Dioxide.

Diamine oxidase and peroxidase, associated with the wall in pinto bean (Phaseolus vulgaris L. var Pinto) leaves, can be washed out by vacuum infiltration and assayed without grinding the leaf. The diamine oxidase activity is inhibited in vivo by exposure of the plants to ozone (dose of 0.6 microliters per liter x hour), whereas the peroxidase activity associated with the wall space is stimulated. This dose does not cause obvious necrosis or chlorosis of the leaf. These alterations are greater when the dose of ozone exposure is given as a triangular pulse (a slow rise to a peak of 0.24 microliters per liter followed by a slow fall) compared to that given as a constant square wave pulse of 0.15 microliters per liter for the same 4 hour period. Exposure of the plants to sulfur dioxide (at a concentration of 0.4 microliters per liter for 4 hours) does not result in any change in the diamine oxidase or peroxidase activities, yet the total sulfhydryl content of the leaf is increased, demonstrating the entry of sulfur dioxide. These two pollutants, with different chemical reactivities, affect the activities of the extracellular enzymes in different manners. In the case of ozone exposure, the inhibition of extracellular diamine oxidase could profoundly alter the movements of polyamines from cell to cell.

Journal Article↗
PubMed1989

Isolation and characterization of myoglobin and its two major isoforms from sheep heart.

We isolated myoglobin from sheep heart by homogenizing cardiac muscle in 70%-saturated ammonium sulfate, followed by chromatography on a column containing carboxymethyl(CM)-Sephadex gel. Two major isoforms of myoglobin, designated Mb 7.9 and Mb 8.1, were separated by chromatofocusing and were distinguished by their different patterns seen on either isoelectrofocusing or on electrophoresis on polyacrylamide gel. The isoelectric points of the major bands of Mb 7.9 and Mb 8.1 were 7.4 and 7.16, respectively. Both isoforms were identical in size when examined by gel filtration chromatography but differed slightly when analyzed by polyacrylamide gradient gel in the presence of sodium dodecyl sulfate. The Mr of Mb 7.9 (15,900 Da) is slightly smaller than that of Mb 8.1 (18,400 Da). When reacted against rabbit anti-sheep myoglobin, two isoforms also appeared as two nonidentical precipitin lines on agarose gel.

Animals↗
PubMed1988

Age-related changes in secretion of luteinizing hormone and metabolism of hypothalamic amines in bull calves prior to puberty.

Effects of age and castration on secretion of luteinizing hormone (LH) and metabolism of hypothalamic monoamines were determined in Holstein bulls. Calves were assigned to be intact or castrated and killed at 8, 12, or 24 wk of age. Animals were castrated and bled every 10 min for 6 h at 96 and 24 h prior to slaughter, respectively. The stalk median eminence (SME), medial basal (MBH), and anterior-preoptic (AHA-POA) hypothalamic regions were obtained at slaughter and assayed for norepinephrine (NE), dopamine (DA), dihydroxy-phenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxyindole-acetic acid (5-HIAA) using high performance liquid chromatography with electrochemical detection (HPLC-EC). Concentrations of LH and testosterone in plasma were determined by radioimmunoassay (RIA). In intact calves, LH pulse frequency (pulses/6 h) increased between 8 and 12 wk (1.4 vs. 3.4) and then declined (1.6 at 24 wk of age). Frequency of LH discharges did not change during the first 72 h post-castration in calves 8 (1.4 vs 1.0) and 12 (3.4 vs. 3.8) wk of age, but increased in 24-wk-old calves during this time (1.6 vs. 6.4). The amplitude of LH pulses increased with age (p less than 0.05) and after castration (p less than 0.05). There were marked regional differences in concentrations of monoamines. However, effects of age and castration on concentrations of monoamines were observed only within the SME where DA, DOPAC and NE increased significantly with age. Plasma concentrations of testosterone were correlated with concentrations of NE and DOPAC within the SME. Changes in 5-HT with age were biphasic; at each age, 5-HT increased after castration. From these data, it is concluded that 1) different mechanisms regulate LH pulse frequency and amplitude in calves as early as 8 wk of age, and 2) differences in hypothalamic metabolism of monoamines may be related to maturational changes in secretion of LH in bull calves.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Air embolism: a serious hazard of central venous catheter systems.

Central venous catheter systems are an important yet little recognised source of serious air embolism. Scrupulous care and vigilant observation of this equipment is necessary to prevent the severe cardio-respiratory and neurological sequelae which may occur. Air embolism following central venous catheterisation is one of the most serious complications of this procedure. We describe an unusual and hitherto unreported mechanism by which air accidentally entered the circulation; fortunately in this case there were no serious sequelae.

Aged↗
PubMed1984

Radiographic evaluation of bovine artificial inseminating technique among professional and herdsman-inseminators using .5- and .25-ml French straws.

Using radiography, inseminating syringe tip location and inseminate distribution in excised bovine reproductive tracts were described for 20 professional and 20 herdsman-inseminators using .5- and .25-ml French straws. Inseminations (20 by each participant) were performed in tracts placed on a device that stimulated the anatomical position of the reproductive organs in vivo. A computer-coupled graphics information digitizer was used to quantitate the precise location of the syringe tip and to estimate the distribution of radiopaque inseminate within the tract from each pair of radiographs. Neither category of inseminator (professional or herdsman) nor volume of inseminate (.5 vs .25 ml) influenced (P greater than .05) syringe tip placement or subsequent distribution of the radiopaque inseminate within the tract. The proportion of syringe tip placements in various anatomical locations (586 attempts) were: uterine body, 39%; cervix, 25%; left uterine lumen, 13% and right uterine lumen, 23%. The variability among inseminators was high, with the ability to position the syringe tip in the uterine body ranging from 0 to 85% of the 20 attempts. Among all inseminators, 82% were unable to place the syringe in the uterine body greater than 60% of the time. When averaged across all inseminations (n = 666), 40% of the inseminate was located in the uterine body and(or) equally distributed in the uterine lumina. The remainder of the inseminate was located in the cervix (17%) or disproportionately in one uterine lumen (43%). Syringe tip placement in the uterine body was correlated (r = .73; P less than .05) with the proportion of inseminate located in the uterine body and(or) equally distributed to the lumen of both uterine horns. Measurements of various anatomical components of the reproductive tract were made from the first radiograph. The means were: cervical diameter, 5.9 cm; length from internal cervical os to external uterine bifurcation, 16.4 cm; uterine body length, 1.7 cm and uterine body surface area, 3.6 cm2. There was no relationship between the palpable anatomical components and uterine body size.

Animals↗
PubMed1984

Long-term venous access.

The aim of this review is to outline the indications and provide a historical perspective of its development. The current complications are emphasized with the hope that greater caution and vigilance will lead to a reduction in their frequency. Finally, details of several techniques are described for gaining long-term venous access for critically ill or injured patients.

Catheterization↗
PubMed1983

Radiographic method for evaluation of bovine artificial inseminating technique.

Radiography was used to visualize the interior of excised bovine reproductive tracts during artificial insemination. Reproductive tracts were placed in a device that simulated the anatomical position of the reproductive organs in vivo. Air was introduced into the uterus to provide differential radiopacity between the uterine lumen and the surrounding soft tissue. Egg yolk extender was saturated with lead acetate to provide radiopacity, thus enabling the inseminate to be visualized following deposition. This radiographic technique enables the insemination syringe tip and the distribution of the inseminate within the reproductive tract to be visualized clearly without dissection.

Animals↗
PubMed1983

The effect of enteral nutritional support on skeletal muscle protein synthesis and whole-body protein turnover in fasted surgical patients.

Whole-body and muscle protein turnover have been studied in surgical patients, before abdominal surgery after an 18-h fast, using infusion of 1-[13C]leucine. Four patients received an unmodified hospital diet and four received extra nutritional support (1800 kcal, 70 g protein) by naso-jejunal tube for 7-10 d previously. In patients who received nutritional support there were significantly greater values of whole-body protein synthesis (+42 per cent, P less than 0.05) and breakdown (+45 per cent, P less than 0.01) and muscle protein synthesis (+36 per cent, P less than 0.05) than in those who received the unmodified hospital diet.

Aged↗