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Biomedical subjects

R Thompson

Publications and source records attributed to R Thompson.

At least 253 records · Page 14Linked to original sources
PubMed1986

Trophoblastic proteins as tumor markers in nonseminomatous germ cell tumors.

In order to examine the relative usefulness of measurements of oncoplacental proteins as tumor markers in patients with nonseminomatous germ cell tumors, the authors measured alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), pregnancy-specific beta 1-glycoprotein (SP1), human placental lactogen (hPL), and placental cystine aminopeptidase (oxytocinase, CAP) in serial blood samples obtained from 26 men with these neoplasms. HCG and AFP were each elevated in 62% of the patients and both were elevated in 38%. SP1 and hPL were increased in 31% and 12%, respectively. None of the patients had elevated CAP activity. Serum hCG and SP1 concentrations were strongly correlated (r = 0.78, P less than 0.001). No patient had an elevated SP1 without a concomitant elevation in serum hCG. Serial measurements of hCG and SP1 indicated that they were concordant in five of the eight patients in whom both were elevated, and AFP and hCG were concordant in only one half of the ten patients in whom both markers were elevated. The number of patients with hPL elevations were too few for meaningful comparison of this marker with the others. These results indicate that measurements of SP1, hPL, and CAP do not provide additional useful information over that obtained from measurements of hCG and AFP in patients with nonseminomatous germ cell tumors.

Chorionic Gonadotropin↗
PubMed1986

Lack of correlation between cortical levels of choline acetyltransferase and learning scores in rats with globus pallidus lesions.

Previous work has shown that rats with lesions of the globus pallidus (GP) exhibit a generalized learning impairment. Data are presented suggesting that this impairment is not due to inadvertent damage to the nucleus basalis magnocellularis. Rats with GP lesions evidenced a significant visual discrimination learning loss and a significant reduction in cortical choline acetyltransferase (ChAT) activity. However, there was no significant correlation between the severity of the learning loss and the amount of reduction of cortical ChAT activity.

Animals↗
PubMed1986

Shadow promoters in the F plasmid transfer operon.

The in vivo transcription start site for PYZ, the promoter of the F plasmid transfer operon, has been located. When transcription start sites for PYZ are deleted, two additional shadow promoters, upstream of PYZ, are activated in vivo. The shadow promoters correspond to those previously identified by in vitro run-off transcription experiments. The activated shadow promoters are stimulated by TraJ protein, a positive regulator of the transfer operon.

Base Sequence↗
PubMed1986

Learning deficits in rats with early neurotoxic lesions to the globus pallidus, substantia nigra, median raphe or pontine reticular formation.

Previous studies have shown that weanling rats with electrolytic lesions of the globus pallidus (GP), substantia nigra (SN), median raphe (MR) or pontine reticular formation (PRF) are deficient in learning a wide variety of laboratory tasks. The current study was designed to investigate whether this nonspecific learning deficiency is due to destruction of cells intrinsic to these subcortical regions or to fibers passing through these regions. Accordingly, neurotoxic lesions of the GP, SN, MR or PRF were made in weanling rats using ibotenic acid. Rats were subsequently required to learn a visual discrimination, a 3-cul maze and a nonvisual (incline plane) discrimination. While those groups with GP, SN or MR lesions showed significant deficits on all three problems, only the animals with GP lesions exhibited deficits comparable in magnitude to those associated with corresponding electrolytic lesions. Animals with lesions to the PRF were impaired only on the nonvisual discrimination. These results suggest that while destruction of neurons alone within the GP, SN or MR can produce a nonspecific learning impairment, the combined destruction of neurons and fibers of passage within the SN, MR or PRF produces a more profound learning deficit.

Animals↗
PubMed1986

The neuroanatomy of mental retardation in the white rat.

A provisional examination of a set of questions pertaining to the neuroanatomical basis of mental retardation was undertaken by assessing the learning ability of 25 different groups of young rats prepared with various cortical and subcortical lesions. The test battery included a visual discrimination, a nonvisual discrimination, a three-cul maze and three separate detour problems. Seven of the 25 groups were impaired in learning all problems (suggestive of a generalized learning impairment) and therefore were viewed as being mentally retarded. One of these groups suffered diffuse multifocal neocortical damage, while the lesions in the remaining six were located either within the parietal cortex, globus pallidus, ventrolateral thalamus, substantia nigra, median raphe or pontine reticular formation. Based upon a variety of observations, it is proposed that the generalized learning impairment seen in our brain-damaged rats, rather than being reducible to a sensory, motor, arousal-motivational-emotional, attentional, inhibitory or recent memory defect, is the product of a defect in "executive" processes.

Animals↗
PubMed1986

Isolated coronary ostial stenosis in women.

Isolated coronary ostial stenosis is a rare condition of unknown etiology previously reported in only 22 patients. Of 2,105 consecutive patients with angiographically defined coronary disease, 27 (1.3%) had 50% or greater stenosis of one or both coronary ostia. Serious complications occurred during angiography in three patients (11%) with one death. Coronary bypass surgery was performed in 25 patients with 1 early death (4.0%) and 1 late death (mean follow-up 28 months). Twenty-two patients (Group 1) had associated multivessel coronary disease, of whom 18 (82%) presented with stable angina of variable duration (43 +/- 53 months) and 10 (46%) were in the New York Heart Association functional class II. The prevalence of risk factors was high, especially among the eight women (3.0 +/- 0.8 per patient), seven of whom had hyperlipidemia. Five patients (Group 2) representing 0.2% of the total had isolated coronary ostial stenosis. All were women (age 41 +/- 6 years). In contrast to patients in Group 1, this group presented with a short history (2.0 +/- 1.7 months) of severe angina and had a low incidence of risk factors (0.8 +/- 0.6 per patient). Histopathologic study in one case showed typical atheroma. Isolated coronary ostial stenosis is a rare lesion occurring predominantly in young or middle-aged women. The clinical and angiographic profile appears unique and, despite the histopathologic findings, suggests a natural history distinct from that usually seen in atherosclerotic coronary disease.

Adult↗
PubMed1986

R plasmid transfer.

This paper is a brief survey of the systems of genetic exchange in bacteria relevant to the spread of antibiotic resistance genes. Emphasis is given to those systems most likely to be important in nature, particularly conjugation. Several recently described examples of conjugation in Gram-positive bacteria are discussed and contrasted with the better studied examples in Gram-negative bacteria.

Bacteria↗
PubMed1986

Ejection fraction determination by MR imaging: comparison with left ventricular angiography.

To determine the accuracy of left ventricular ejection fractions (EFs) calculated from magnetic resonance (MR) images, 22 patients who underwent coronary angiography and left ventriculography were studied within 1-3 days by MR imaging. ECG-gated spin-echo 30-msec echo-delay images were obtained in end systole and end diastole in a plane through the long axis of the left ventricle perpendicular to the septum at a level through the aortic valve and apex. The area-length method was then used to calculate the EF from left ventriculograms and MR images. Angiographic EF correlated linearly with MR determinations. The mean differences in EF calculation between two observers were 5.0 +/- 6.9 for ventriculography and 2.7 +/- 7.8 for MR imaging. MR imaging, using image planes oriented to the left ventricular axes, can allow accurate EF calculation. This has the potential to be clinically useful in noninvasive evaluation of cardiac function.

Adult↗
PubMed1986

Influence of transdermal nitrates on exercise capacity in patients with stable angina.

Twenty patients completed a double-blind cross-over study to determine the influence of a transdermal preparation of Nitroglycerin on exercise performance in stable angina. Angiographically proven two or three vessel coronary disease was present in all. After a base-line exercise test the active device was titrated to efficacy or side effects and the number of patches thereafter remained constant (2-6 patches per day; mean 3.5). Patients were randomly allocated to active treatment or placebo, and further exercise tests were performed at 2 hours and 26 hours after application of the device. Patients were then crossed over after one days rest to the opposite treatment group, and exercise studies repeated. Two hours after application of transdermal nitroglycerin total exercise duration increased (mean 14.0 minutes) compared to placebo (12.5 minutes) and control (12.0 minutes) (p less than 0.05). This effect was maintained at 26 hours. Exercise time to anginal threshold (angina + 1.5 mm ST segment depression) was increased at 2 hours and 26 hours with active drug by 11% compared to placebo and by 22% in comparison to control. Double product of heart rate and blood pressure was not significantly different in treated and placebo groups. Oral nitroglycerin consumption assessed during the titration phase was reduced by 71%. It is concluded that transdermal nitroglycerin significantly increases exercise capacity in patients with stable angina, with an effect that is maintained over a 24-hour period using a single dose application.

Administration, Topical↗
PubMed1986

Magnetic resonance imaging of thoracic aortic aneurysms: comparison with other imaging methods.

Fifteen patients with thoracic aortic aneurysms had magnetic resonance images (MRI) and at least one additional diagnostic image study: thoracic aortography, computed tomography (CT), or two-dimensional echocardiography. Twenty aneurysms were demonstrated by MRI, 19 by the other studies. One small saccular aneurysm was missed by CT. There was complete agreement between MRI and other studies regarding aneurysm morphology, and good correlation in diameter measurements of the aneurysms and at multiple additional aortic levels.

Adolescent↗
PubMed1986

Effect of long-term azathioprine administration in adults with minimal-change glomerulonephritis and nephrotic syndrome resistant to corticosteroids.

Thirteen adult patients with nephrotic syndrome resistant to corticosteroid administration were treated with azathioprine daily for four years. Progressive improvement occurred in all 13 patients so that they were in complete remission after one to three years. The onset of apparent improvement was earlier and the rate of progressive improvement more rapid in patients who had selective proteinuria before therapy than in those whose proteinuria was nonselective. One patient who stopped therapy after 20 months suffered relapse but again responded when azathioprine treatment was restarted. Observation after the four-year therapeutic period ranges from three to 15 years; there have been no relapses during this time.

Adolescent↗
PubMed1985

Late results of valve replacement and factors influencing survival in patients with severe chronic mitral regurgitation.

Between July 1967 and September 1981 50 patients with isolated severe mitral regurgitation underwent mitral valve replacement. There were 29 males and 21 females (mean age 52 years). The aetiology of the valve lesion was rheumatic in 14 patients (mean age 42 years) and non-rheumatic in 36 patients (mean age 56 years). At the time of operation 36 patients (72%) were in class 3 or 4 of the New York Heart Association classification (mean duration of symptoms 20 months). Pre-operative ejection fraction was normal in only four patients (8%) and was below 0.50 in 27 patients (54%). There were two early deaths (4%) within one month of operation, and 17 late deaths (34%) during a follow-up period of four months to 10 years (mean 43 months). Actuarial analysis showed a 71% survival at five years and a 62% survival at 10 years after valve replacement. Of the 31 current survivors, 22 (71%) are in class 1 of the New York Heart Association classification, and all but two patients showed significant improvement in symptoms. Significant morbidity after operation occurred in 10 patients (20%) and was largely related to problems with anticoagulant control. Analysis of factors which may influence survival, showed that age greater than 55 years and parameters of left ventricular geometry, demonstrated by angiography, were the major determinants of survival.

Adult↗
PubMed1985

Deficits in response inhibition and attention in rats rendered mentally retarded by early subcortical brain damage.

Young rats with lesions to either the globus pallidus, substantia nigra, median raphe, or pontine reticular formation have previously been reported to be deficient in learning a wide variety of laboratory tasks. In the current study, weanling rats subjected to one of these lesions were rested for three weeks, then examined for acquisition and extinction of a water-motivated straight alley task, and finally tested on luminous flux discriminations of increasing difficulty. All brain-damaged groups were slower than the controls in extinguishing the alley task and only the median raphe group failed to show an impairment on the discrimination problems. These results and others suggest that the foregoing lesions produce deficits in inhibitory and attentional processes. The possibility is discussed that young rats bearing these lesions might serve as a model for the investigation of the neurobiological and cognitive disturbances underlying certain classes of mental retardation in children.

Animals↗
PubMed1985

The comparative effects of frontal, parietal, occipitotemporal, and limbic forebrain lesions in weanling rats on learning.

Young rats prepared with discrete bilateral lesions to the cerebral cortex, cingulate cortex, or dorsal hippocampus were required to learn a white-black discrimination, a 3-cul maze, and a nonvisual inclined plane discrimination. Only those rats with parietal lesions were impaired in acquiring all three habits. Those with occipitotemporal, frontocingulate, or posterior cingulate lesions were impaired on two habits, those with dorsal hippocampal lesions were impaired on one habit, and those with frontal (motor) cortical lesions failed to show any impairment. These results coupled with others suggest that the parietal cortex is unsurpassed in the wide range of learning and retention deficits which follows restricted neopallial lesions.

Animals↗
PubMed1985

Marijuana use does not spuriously elevate serum human chorionic gonadotropin levels.

Marijuana use has been reported to spuriously elevate immunoreactive human chorionic gonadotropin (HCG) in the serum of patients with testicular germ cell tumors. To reinvestigate this finding, we measured serum HCG and delta 9-tetrahydrocannabinol (delta 9-THC) levels in 16 men known or suspected to be marijuana users. Eight of the serum samples had measurable levels of delta 9-THC, while eight did not. None contained immunoreactive HCG. The addition of delta 9-THC directly to pooled male serum had no effect on the HCG radioimmunoassay. These results indicate that marijuana does not artificially elevate serum HCG concentrations.

Cannabis↗
PubMed1985

Expired air carbon monoxide and saliva thiocyanate: relationships to self-reports of marijuana and cigarette smoking.

This study examined the relationship between self-reports of marijuana and cigarette smoking, and the physiological measures of expired air carbon monoxide (CO) and saliva thiocyanate (SCN) in a sample of 1,130 seventh, ninth, tenth, eleventh, and twelfth graders. Subjects who reported marijuana smoking were likely to also report cigarette smoking. The correlation between self-reported marijuana smoking and SCN was negligible. The correlation between CO and self-reported marijuana smoking was statistically significant, but when the variance due to cigarette smoking was removed, this relationship also became negligible. The existence of a sizeable number of marijuana smokers in this sample of adolescents did not alter the correlation between CO and self-reports of cigarette smoking. However, in adult samples, where marijuana and cigarette smoking are less highly correlated, marijuana smoking could affect the relationship between CO and self-reported cigarette smoking. Carbon monoxide predicted self-reported cigarette smoking better than did saliva thiocyanate. There was an interaction between grade and the CO/cigarette smoking correlation. The correlations were generally higher in upper grades.

Adolescent↗
PubMed1985

Effects of thoracic spinal cord transection on colonic motor activity in rats.

The resting colonic motor activity before and consecutively after spinal cord transection was recorded in male Sprague-Dawley rats. Recording probes were anchored surgically in the ascending and descending colon. Pressure changes were recorded on a dynograph using a low compliance perfusion system. A motility index took into account the amplitude, duration and frequency of contractions. Following a baseline recording animals were subjected either to spinal cord transection at T4 level or a sham operation. The recording sessions continued regularly on alternate days for the observation period of 3 weeks. Transection of the thoracic spinal cord markedly reduced the motility index of the distal colon on the first postoperative day. However, the motor activity gradually returned to pre-operative values after 7 days. Sham surgery did not influence the motor activity. These findings suggest that colonic motor activity is influenced by spinal shock and probably by different neural mechanisms mediating proximal and distal activities of the colon in rats.

Animals↗