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Biomedical subjects

J E Thompson

Publications and source records attributed to J E Thompson.

At least 289 records · Page 16Linked to original sources
PubMed1978

Asymptomatic carotid bruit: long term outcome of patients having endarterectomy compared with unoperated controls.

During 20 years (1957-1977), 1286 carotid endarterectomies were performed on 1022 private patients with cerebrovascular insufficiency. Included were 132 patients undergoing 167 endarterectomies for asymptomatic cervical carotid bruits. Ages ranged from 42 to 82 years (mean: 64.7). Operative mortality was zero. There were two transient and two permanent operation-related neurologic deficits. Complete follow-up was achieved, extending to 184 months. During postoperative follow-up, six patients (4.5%) developed TIA's appropriate to the unoperated artery, three patients had strokes (2.3%), and three patients died of strokes (2.3%). To characterize the natural history of asymptomatic bruit and determine proper indications for prophylactic endarterectomy, a control series of 138 additional patients with asymptomatic bruit not operated upon when the bruit was discovered was studied. Ages ranged from 39 to 86 years (mean: 65.7). During follow-up extending to 180 months, 77 patients (55.8%) remained neurologically asymptomatic, 37 patients (26.8%) developed TIA's one month to 99 months after detection of bruit, and 24 patients (17.4%) sustained mild to profound frank strokes one week to 124 months postdetection. Three of these 24 (2.2%) died of stroke. Asymptomatic carotid bruits may be potential stroke hazards, the risk of which can be significantly reduced by appropriately applied endarterectomy. A protocol for managment is presented.

Adult↗
PubMed1978

Phase Behavior of Chloroplast and Microsomal Membranes during Leaf Senescence.

Wide angle x-ray diffraction of chloroplast and microsomal membranes from primary leaves of Phaseolus vulgaris has revealed that for both types of membrane, portions of the lipid become crystalline as the tissue senesces. For young leaves the transition temperature is about 23 C for microsomes and below -30 C for chloroplast membranes, indicating that at physiological temperature the lipid is entirely liquid-crystalline. Between 2 and 3 weeks after planting the transition temperature rises to 38 C for microsomes, but for chloroplasts this increase to a point above physiological temperature does not occur until between 3 and 4 weeks. Thereafter the transition temperature continues to rise for both types of membrane with advancing senescence, although the rate of increase is greater for chloroplasts than for microsomes. The appearance at physiological temperature of gel phase lipid in the microsomes coincides temporally with the initiation of a decline in total protein in the tissue, and the incidence of crystallinity in chloroplasts coincides with loss of chlorophyll. This change in phase behavior cannot be attributed to an alteration in fatty acid composition, but for both membrane systems it correlates with an increase of about 4-fold in the sterol to phospholipid ratio.

Journal Article↗
PubMed1978

Characteristics of statistical parameters used to interpret least-squares results.

This paper discusses properties of several statistical parameters that are useful in judging the quality of least-squares fits of experimental data and in interpreting least-squares results. The presentation includes simplified equations that emphasize similarities and dissimilarities among the standard error of estimate, the standard deviations of slopes and intercepts, the correlation coefficient, and the degree of correlation between the least-squares slope and intercept. The equations are used to illustrate dependencies of these parameters upon experimentally controlled variables such as the number of data points and the range and average value of the independent variable. Results are interpreted in terms of which parameters are most useful for different kinds of applications. The paper also includes a discussion of joint confidence intervals that should be used when slopes and intercepts are highly correlated and presents equations that can be used to judge the degree of correlation between these coefficients and to compute the elliptical joint confidence intervals. The parabolic confidence intervals for calibration cures are also discussed briefly.

Chemistry, Clinical↗
PubMed1977

Evidence for a cytosol counterpart of the major plasma membrane protein in Acanthamoeba castellanii.

Isolated plasma membranes from Acanthamoeba castellanii incorporated radio-activity when incubated in a corresponding labelled cytosol fraction. The incorporation increased linearly with time and reached saturation at high cytosol: membrane protein ratios in the incubation mixture. Polyacrylamide gel electrophoresis of treated membranes showed that the major protein, which comprised 40 to 50% of the total, was labelled, suggesting that it had exchanged with a radioactive cytosol counterpart. The same protein was discernible in polypeptide profiles of labelled cytosol and showed a higher specific radioactie membrane by solutions of high ionic strength or chelation, this protein appears to be integral rather than peripheral.

Amoeba↗
PubMed1977

Lipid crystallization in senescent membranes from cotyledons.

Lipid transition temperatures for rough and smooth microsomal membranes isolated from bean (Phaseolus vulgaris) cotyledon tissue at various stages of germination were determined by wide angle x-ray diffraction. The transition temperatures were established by recording diffraction patterns through a temperature series until a sharp x-ray reflection centered at a Bragg spacing of 4.15 A and denoting the presence of crystalline lipid was discernible. For rough and smooth microsomes from 2-day-old tissue, the transitions occurred at 0 C and 3 C, respectively, indicating that at this early stage in the germination sequence the membrane lipid is entirely liquid-crystalline at physiological temperature. By the 4th day of germination, the transition temperatures had increased to 32 C for smooth microsomes and 35 C for rough microsomes, indicating that at 29 C, which was the growth temperature, portions of the membrane lipid were crystalline. During the later stages of germination, the transition temperature for smooth microsomes continued to rise through 44 C at day 7 to 56 C at day 9, by which time the cotyledons were extensively senescent and beginning to abscise. There was also a dramatic increase in the proportion of membrane lipid in the crystalline phase at 29 C. By contrast, the rough microsomes showed little change in transition temperature and only a slight increase in the proportion of crystalline lipid during this late period in germination. The data indicate that substantial amounts of the lipid is senescing membranes are crystalline even at physiological temperature. Moreover, there is a temporal correlation between the appearance of this crystallinity and loss of membrane function, suggesting that the two may be causally related.

Journal Article↗
PubMed1976

Phagocytosis and pinocytosis in Acanthamoeba castellanii.

Endocytotic activity of Acanthamoeba trophozoites attenuates once the cells enter stationary phase in liquid culture. Phagocytosis, monitored by the ingestion of polystyrene latex beads, essentially ceases and the uptake of [3H]inulin, known to be mediated by pinocytosis, is reduced by about half. The reduced pinocytotic activity of stationary-phase cells remains sensitive to respiratory inhibitors. Preincubation of stationary-phase cells in fresh growth medium for 1-5 h before the initiation of endocytosis has no effect on phagocytosis and only marginally increases pinocytosis. This impairment of ingestion, particularly of pinocytosis, may account for the reduced contractile vacuole activity known to characterize stationary-phase cells of this organism. The unequal responses of phagocytosis and pinocytosis to the onset of stationary-phase growth suggest that they are independent processes subject to different controls.

Animals↗
PubMed1976

The effect of rifampicin on liver morphology in tuberculous alcoholics.

Seventy-nine consecutive patients receiving rifampicin in combination with isoniazid and another drug, were found to have an 8-3% incidence of acute clinical liver disease. Half the patients (36) were advanced alcoholics and almost all cases of hepatitis came from this group. Fifteen of the 36 were thought to have evidence of pre-existing liver disease and were studied by means of serial liver biopsies. Most of those with pre-treatment abnormalities of liver function developed abnormalities in their biopsies, not attributable to alcohol. In one patient active chronic hepatitis is believed to have followed irregularly taken rifampicin. Those patients with both normal pretreatment liver function and biopsies did not develop histological abnormalities. The dangers of irregularly taken self-administered rifampicin are stressed. It is suggested that rifampicin is contraindicated in alcoholics with initial abnormal liver function tests.

Adult↗
PubMed1976

Management of asymptomatic carotid bruits.

Asymptomatic carotid bruits may originate in the internal carotid artery from atherosclerotic plaques which predispose to strokes in certain individuals over the age of 40. Certain recently developed noninvasive screening tests are helpful in determining the hemodynamic significance of these bruits, which ultimately require arteriography to determine precise diagnosis and significance. If hazardous lesions are demonstrated, carotid endarterectomy may be recommended for selected patients without multiple risk factors to prevent the occurrence of ischemic cerebral episodes.

Angiography↗
PubMed1976

Autologus saphenous vein femoropopliteal bypass: analysis of 298 cases.

A retrospective review of 298 saphenous vein femoropopliteal bypasses performed for femoral artery occlusive disease over a 13 year period was carried out. The purpose of the study was to assess factors which influence long-term graft patency. Follow-up was 95.3 percent complete. Results were analyzed with the aid of IBM data processing equipment and standard statistical methods.

Aged↗