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Biomedical subjects

S Ross

Publications and source records attributed to S Ross.

At least 217 records · Page 12Linked to original sources
PubMed1984

Kinetics and thermolability of platelet monoamine oxidase in cluster headache and migraine.

Platelet monoamine oxidase activity (MAO) from 33 cluster headache patients (17 males, 16 females) and 34 migraine patients (16 males, 18 females) was assayed. The kinetic constants (apparent Vmax and apparent Km) and the thermolability, measured as the ratio of the platelet MAO activity after and before heat treatment (+52 degrees C, 30 min), were determined. The MAO activity and Vmax values were significantly lower in cluster headache than in migraine and in both headache disorders compared to a control group (62 males, 66 females). When comparing all groups, Km was not significantly different except for migraine females, who had lower Km values compared to control females. Thermolability was significantly higher in cluster headache than in migraine and in both headache disorders compared to the control group. Smokers of five cigarettes or more per day had significantly lower Vmax values but similar Km and thermolability values compared to those smoking less or nothing. The findings of low maximal velocities and high thermolability of platelet MAO in cluster headache and migraine are suggested to represent constitutionally different enzyme properties.

Adolescent↗
PubMed1984

Effect of temperature and length of storage on serum-stimulated and serum-independent lipolytic activities in human milk.

Milk was collected from five mothers. Upon collection, serum-stimulated and serum-independent lipolytic activities were determined. The milk samples were aliquoted and stored at 25, 4, -20, and -70 degrees C. After storage for 3, 6, 12, and 24 h, serum-stimulated and -independent activities were again determined and compared with the initial activities. Storage at 25 degrees C resulted in a significant (p less than 0.05) decrease in lipolytic activity. Serum-stimulated activity decreased 83.4% and serum-independent activity decreased 66.9% over the 24-h period. Storage at 4 degrees C resulted in a significant (p less than 0.05) decrease of 22.6% in serum-stimulated activity and a 7.2% decrease in serum-independent activity. No significant changes were observed in milk stored for 24 h at -20 and -70 degrees C. Milk was stored at -20 and -70 degrees C for an additional 1, 2, and 4 weeks. Serum-stimulated lipolysis did not change significantly over the 4-week period. Serum-independent lipolysis increased significantly (p less than 0.05) with storage time. Storage at -20 degrees C resulted in an increase of 20% and storage at -70 degrees C resulted in an increase of 36% over the 4 weeks.

Female↗
PubMed1984

The maximum exercise stress test: is it a behavior-modification tool?

The controlled study presented demonstrates the results obtained when using the maximum exercise stress test (MEST) as a behavior-modification tool for coronary artery disease risk factors. Changes in attitudes, behaviors, and objective measurements of health were assessed in a low-risk population. Only exercise level was significantly altered (P less than .03). Changes in the other measured parameters were insignificant. The MEST test is also expensive, and no benefit has been demonstrated in terms of its ability to decrease the morbidity and mortality seen in coronary artery disease.

Adult↗
PubMed1984

Antiemetics.

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Antiemetics↗
PubMed1983

Serum dopamine-beta-hydroxylase in diagnostic subgroups of depressed patients and in relation to their personality characteristics.

Serum dopamine-beta-hydroxylase (DBH) levels were assessed in 150 depressed patients of both sexes, with a mean age of 44.0 +/- 12.3 (SD) years. Patients were divided into unipolars (n = 46), bipolars (n = 25), neurotic-reactive (n = 46) and unspecified (n = 38) i.e., those who did not fit into any of the previous categories. According to their status 38 patients were psychotic and 104 clearly nonpsychotic at the time of the DBH assessment. Personality characteristics were assessed for the same patients when they had markedly improved from their depression. In line with previous findings bipolar patients were found to have slightly lower serum DBH values than unipolars, and psychotic patients slightly lower values than nonpsychotic. However, none of the differences among diagnostic groups or between psychotic and nonpsychotic patients was statistically significant. Weak negative correlations were found between serum DBH and the personality variables social desirability and indirect aggression, but an earlier finding of a positive correlation with the personality trait monotony avoidance, could not be confirmed. Owing to the large interindividual variations in serum DBH it is concluded that correlations between serum DBH and personality characteristics might be spurious and due to chance. This study does not support the assumption that significant differences in serum DBH might occur among subgroups of depressed patients.

Adjustment Disorders↗
PubMed1982

Coitus and chorioamnionitis: a prospective study.

Amniotic fluid infections have been strongly associated with coitus during pregnancy. If the relationship is causal it may be possible to identify a time sequence between coitus, penetration of bacteria through the mucous plug in the cervix, the development of infection in the extraplacental membranes near the cervical os, spread of the infection to the amniotic fluid and complications of the infection. The present study looked for such a sequence in an analysis of 541 pregnancies. A peak frequency of chorioamnionitis limited to the extraplacental membranes was present when labor and delivery took place within two days of the last coitus. In the next two days the infection spread to the amniotic fluid as evidenced by a peak frequency of maternal neutrophils migrating through the placental plate toward the amniotic cavity. Premature delivery was 4 times more frequent when there had been recent coitus and an amniotic fluid infection was present than when either factor was absent (P less than 0.01). Spontaneous rupture of the fetal membranes before the onset of and the membranes were inflamed than when these factors were absent (P less than 0.01). This raises the possibility that orgasm further weakened or ruptured membranes that had already been weakened by infection.

Amnion↗
PubMed1982

Four-contact glove probe method for rapid recording of cardiac electrograms during surgery.

A technique is presented for recording four simultaneous electrograms from the heart during operation for cardiac arrhythmias. this technique permits intraoperative maps of cardiac electrical activity to be constructed more rapidly than is possible with single-point mapping, thereby decreasing the risks to the patient and yielding more information about cardiac events.

Arrhythmias, Cardiac↗
PubMed1982

A model of the hair cell-primary fiber complex.

The proposed model consists of a chain of three energy reservoirs through which energy from an infinite supply is fed to a modulator which in turn drives a firing mechanism. The modulator consists of a variable permeability p that depends on instantaneous basilar displacement a through: p = (a - AO)2 for a greater than AO, and p = O for a less than or equal to AO, where AO is a constant. The firing mechanism consists of a Poisson generator (process) whose average output rate is proportional to energy flow through the modulator, and a classical "leaky integrator" neuronal model driven by the Poisson generator. The model, containing three fixed and eight free parameters, was examined with respect to statistical properties of spontaneous activity, relation between overall firing rate and level of stimulation, various adaptation and recovery phenomena within time ranges from a few milliseconds to several seconds, period histograms for one- and two-tone (phase locked) stimulation, suppression of responses to one tone by subthreshold levels of another (phase locked) tone, and neural masking. Model behavior in general was satisfactory. Deficiencies in single-cycle histograms at medium and high levels, and insufficient onset peaking in PST histograms, were attributed to the malfunctioning of one particular segment of the model, and a possible remedy was suggested.

Acoustic Stimulation↗
PubMed1982

Evaluation of cefaclor in acute otitis media caused by ampicillin-resistant H. influenzae.

Cefaclor was used to treat 13 children with acute otitis media caused by ampicillin-resistant strains of Hemophilus influenzae. The children were re-examined on days 4, 10, and 28. Pharmacologic compliance was assessed by means of a bioinhibition assay on a urine specimen obtained on days 4, 7, and 10. Nine of the 13 children had evidence by tympanogram of residual otitis media with effusion (secretory otitis media). Of these, three were noted to have a bulging, yellow or grey eardrum, which suggested an ongoing acute process. A second middle ear culture was obtained from two of the 3 children, but no pathogens were recovered. Two others had recurrence of otitis shortly after cessation of therapy. Cefaclor is an acceptable antibiotic for the treatment of ampicillin-resistant acute otitis media; but, after cefaclor therapy, some children continued to have a bulging eardrum and sterile pus in the middle ear or had recurrences of otitis soon after cessation of therapy.

Acute Disease↗
PubMed1982

Vitreous variation in vitreous fluorophotometry.

Clinical vitreous fluorophotometry is a technique used to evaluate the early breakdown of the blood-retina barrier, which is often seen in diabetic retinopathy. However, the test does not take into account the possibility of individual variations of fluorescein diffusion in the vitreous body. This study undertook to follow the diffusion of a fluorescein solution in 20 different bovine vitreous bodies in a laboratory setting. The results showed a broad distribution of fluorescein diffusion in the sampled population. By statistical analysis, at least three subgroups, differing with respect to the fluorescein dye diffusion pattern, were identified. Further experiments suggest that variation in hyaluronic acid structure in vitreous bodies might account for these differences.

Animals↗
PubMed1981

DSP4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine)--a useful denervation tool for central and peripheral noradrenaline neurons.

The effect of N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4) on monoamine neurons was studied in mice and rats. In mice DSP4 produced acutely a marked reduction of endogenous noradrenaline (NA), [3H]NA uptake and nerve density of the adrenergic nerves in the iris and atrium. Pronounced accumulations of NA were observed in non-terminal axons, which is a degenerative sign, while no changes were found in the NA cell bodies. A marked recovery of all parameters analysed was found as soon as 1 week after DSP4. In the mouse CNS, however, there was a marked and long-lasting NA reduction, especially in the cerebral and cerebellar cortex and spinal cord, leaving dopamine (DA) and serotonin (5-HT) neurons apparently unaffected. Administration of DSP4 to adult rats produced regional changes in the NA levels of the CNS were similar to those observed in the mouse. There were no indications of DSP4 affecting dopamine and adrenaline neurons in rat CNS, although a minor 5-HT depleting effect was noted. DSP4 treatment resulted in an increase in beta-adrenoceptor binding in vitro to homogenates from the cerebral cortex, using [3H]dihydroalprenolol as radioligand. Treatment of newborn rats with DSP4 caused permanent NA disappearance in the cerebral cortex and spinal cord, whereas marked NA increases were found in the pons-medulla and cerebellum. Administration of DSP4 to pregnant rats (gestation day 15) led to a marked and permanent NA depletion in the cerebral cortex and spinal cord in the offspring. The results support the view that DSP4 can produce an acute and relatively selective degeneration of NA nerve terminals in the rat and mouse. The results furthermore indicate that DSP4 (systemically administered) causes a preferential degeneration of NA nerve terminal projections originating from the locus coeruleus in the CNS. Since DSP4 can pass both the blood-brain and blood-placenta barrier and appears to have potent neurotoxic actions on NA neurons, DSP4 may serve as a useful denervation tool for the analysis of NA transmitter functions, particularly in the CNS of both adult and developing animals.

Amines↗
PubMed1981

Selection of plasma for hepatitis B immune globulin using a low cost radioimmunoassay.

Polystyrene beads coated with pasteurised polyethylene glycol-precipitated HBsAg were used to detect anti-HBs by a solid phase inhibition assay employing unreacted 125I-anti-HBs which had previously been "processed" by polyethylene glycol precipitation and used to test for the HBsAg. A weak anti-HBs (approximately 0.1 IU/ml) positive control was used to establish a target level of reactivity. 16,035 freshly donated units of blood, a 90-sample coded anti-HBs panel and a selection of hyperimmune globulins were investigated. All positive results were confirmed by a standard commercial assay. Antibody content of selected samples was quantitated in international units. A target level of anti-HBs activity is suggested for donor plasma to be fractionated for the production of hepatitis B immune globulin.

Adsorption↗