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Biomedical subjects

S Evans

Publications and source records attributed to S Evans.

At least 325 records · Page 18Linked to original sources
PubMed1983

Measurement of nerve conduction--a comparison of orthodromic and antidromic methods.

The validity of the antidromic method in the measurement of median and ulnar sensory nerve conduction is determined. Analysis of our results show that both the orthodromic and antidromic methods provide consistent results. Both methods were accurate in diagnosing Carpal Tunnel Syndrome (CTS), with an upper limit of normal for distal sensory latency of 4.5 msecs motor, and 4.0 msecs sensory in the median nerve. Variation with age and sex was studied. Latency when measured by either method showed no variation. Amplitude showed a consistent decrease with age. No sex difference was detected. We conclude that the antidromic stimulatory method is accurate, reproducible, and convenient, and therefore is at least as good if not better than the orthodromic method in the context of a busy routine electrodiagnostic clinic.

Adolescent↗
PubMed1983

Cutaneous factors related to the risk of malignant melanoma.

In a case-control study, 287 women with malignant melanoma were compared with 574 age-matched controls. Red hair colour at age 5 years was associated with a tripling of risk [relative risk (RR) = 3.0], blonde hair with a 60% increase (RR = 1.6) and fair skin with a doubling (RR = 2.1). Women with melanoma also reported that they tended to burn (RR = 1.4) and to freckle (RR = 1.9) after exposure to sunlight. Since fair skin, red hair, and the tendency to burn or freckle after exposure to sunlight all cluster in the same individuals, the extent to which each of these factors had an independent influence on susceptibility to melanoma was investigated. Hair colour, especially red hair, proved to be the major determinant, followed by skin colour. The reporting of above average numbers of naevi on the body was as strong a predictor of melanoma as was red hair colour (RR = 3.4). A history of psoriasis was also more common in cases than controls (RR = 3.0) as was a history of vitiligo (RR = 1.8). A history of acne appeared to be protective (RR = 0.4) as did a history suggestive of chloasma (RR = 0.6) and premature greying of the hair (RR = 0.6). These relationships were irrespective of hair and skin colour.

Adolescent↗
PubMed1983

Isotopic and enzymatic IgE assays in non-allergic subjects.

In order to establish normal values in an adult population for serum IgE concentration, sera were obtained from 446 ambulatory Canadian caucasian subjects with negative allergy histories. A standard isotopic procedure, the Phadebas paper radioimmunosorbent test (PRIST), was compared with the new enzymatic counterpart, the Phadezyme PRIST. By the isotopic method, serum IgE concentrations in women and men were comparable from one age group to another with no age-related trend in the seven age groups examined (15-20, 21-30, 31-40, 41-50, 51-60, 61-70, above 70). The median and 95th percentile units (U)/ml respectively were 17.5 and 145 for 224 women and 25.5 and 275 for 222 men. Mean values +/- 1 SD for women were 43 +/- 102 and for men, 58 +/- 137. Levels were significantly higher in men as a group. Sera with IgE concentrations above 100 U and a sampling of additional sera were tested for specific IgE antibodies to 13 common allergens by the radioallergosorbent test (RAST). After exclusion of RAST-positive sera, the mean U/ml values +/- 1 SD were 22 +/- 29 for 204 women and 37 +/- 54 for 196 men. Geometric mean U/ml values for these sera were 14.6 for women and 22.3 for men and the median and 95th percentile U/ml respectively for the women were 15 and 66, for the men, 24 and 135. These 95th percentile values are considered the upper limits of normal in this population. The RAST identification of antibodies to allergens to which sensitization was demonstrated provided a potential explanation for serum IgE concentrations above 100 U/ml in less than 30% of the sera in this population with negative allergy histories. The isotopic method and the counterpart enzymatic method (Phadezyme PRIST) were highly comparable; the correlation coefficient (r) for all the sera was +0.93 (P less than 0.001). IgE levels were significantly higher in male smokers than non-smokers by both methods but these differences were not significant in women.

Female↗
PubMed1983

Detection of free kappa chains in human serum and urine using pairs of monoclonal antibodies reacting with C kappa epitopes not available on whole immunoglobulins.

The properties of five monoclonal antibodies (McAbs) which react with free kappa chains but not with IgG kappa, IgM kappa or IgA kappa have been studied. IgG preparations stored for long periods sometimes contained low and high molecular weight material reacting as free kappa. This could be removed by passing the preparation through an affinity column to which two of the McAbs had been coupled, but reactive material reappeared when the purified IgG was heated at 65 degrees C. Two of the McAbs from one fusion reacted with F(ab')2 fragments of IgG whereas two from another fusion did not. Pairs of McAbs (one from each fusion) were much more sensitive in the detection of free kappa, particularly monomer, than a single McAb. This provided the basis for a very sensitive method of detection of free kappa chains in human body fluids and culture supernates.

Antibodies, Monoclonal↗
PubMed1982

Fluorescence measurement of lesion-induced fiber growth. II. Measurement of sympathohippocampal sprouting using a new microfluorometric method.

A microfluorometric (MF) method for measuring areal density and fiber intensity of fluorescent catecholamine fibers and varicosities was described in the previous paper. This method was then used to quantify sympathetic growth observed in the hippocampus after damage to the septal area. Because this MF method does not distinguish between catecholamine fibers of central and peripheral origins, several different ways to measure sympathetic ingrowth were used. First, the ingrowth was measured in subiculum, which has a naturally sparse innervation of central catecholamine fibers. Second, multivariate analyses were used to distinguish between: (1) sham animals -- with central innervation; (2) animals with septal lesions -- with central and peripheral innervation; and (3) sympathectomized septal animals -- with peripheral innervation removed. Finally, a polynomial regression analysis was used to identify the changes in catecholamine innervation over time that suggested a decrease in central innervation with a subsequent increase in the ingrowth of sympathetic fibers. The resulting data converge in support of the objective microfluorometric measurement of sympathohippocampal ingrowth in our histofluorescence preparations.

Animals↗
PubMed1982

Malignant melanoma and exposure to fluorescent lighting at work.

In a study of 274 women with malignant melanoma, aged 18--54 years, and 549 matched controls in New South Wales, Australia, reported exposure to fluorescent light at work was associated with a doubling of melanoma risk (relative risk [RR] = 2.1; 95% confidence limits 1.32--3.32). The risk grew with increasing duration of exposure to fluorescent light and was higher in women who had worked mainly in offices (RR = 2.6) than in women whose main place of work was indoors but not in offices (RR = 1.8). The findings could not be explained by the differences in histories of sunlight exposure, in skin or hair colour, or in any other factor. There was a relative excess of lesions on the trunk in the group exposed to fluorescent light at work. 27 men with melanoma and 35 similarly aged controls were studied, and a significant increase in risk was also found: the RB in those exposed for greater than or equal to 10 years compared with those exposed for less than 10 years was 4.4 (95% confidence limits 1.1--17.5). Such an association has not been reported before, but it is plausible and could explain many of the paradoxical features of the epidemiology of melanoma. Until more data accumulate it must, however, be viewed cautiously.

Adolescent↗
PubMed1982

The lumbar interspinous bursae and Baastrup's syndrome. An autopsy study.

This study describes the prevalence, distribution, pathology and pathogenesis of lumbar interspinous bursitis (described as a clinical syndrome by Baastrup in 1933). It is based on an anatomic study of 152 lumbar spines derived from routine and random postmortem material, together with selected specimens from autopsies on patients with various rheumatic diseases. From a statistical study of 50 randomly chosen spines, bursae are found when the interspinous distance is small compared with the total height of the lumbar spine ('bursal index'): nearly all bursal spaces show some sign of inflammation and a few show severe bony erosion. Crystal deposits therein are also described.

Arthritis, Juvenile↗
PubMed1982

Occupational asthma caused by nickel sulfate.

A 28-yr-old man developed asthma shortly after being exposed to nickel sulfate (NiSO4) in a metal-plating factory. Recordings of peak expiratory flow rates at work and for an off-work period showed increased variations at work, with best values on weekends. Allergy prick skin tests elicited an immediate reaction with NiSO4 at a concentration of 10 mg/ml. Experimental inhalation challenges with NiSO4 at the same concentration of 10 mg/ml for 60 sec produced a bronchial obstruction typical of an early asthmatic response. A control asthmatic subject with a similar level of sensitivity to histamine failed to react after the same inhalation of NiSO4, which suggests a specific rather than irritant mechanism for the reaction. the patient had evidence of IgE antibody to a NiSO4-human serum albumin antigen. His serum selectively bound 63 Ni, and the test was selectively blocked by nonlabeled nickel sulfate. These results, evaluated together, suggest the development of occupational asthma caused by allergy to NiSO4 in this patient.

Adult↗
PubMed1982

Danazol in the treatment of endometriosis: analysis of 100 cases with a 4-year follow-up.

A prospective study to evaluate the efficacy of danazol in the treatment of endometriosis was initiated in 1976. One hundred patients with endometriosis, as demonstrated by laparoscopy, were entered into the study. The mean length of patient follow-up was 49 months. All patients were treated with 800 mg of danazol per day. The mean duration of danazol therapy was 17.3 weeks. Eighty-nine percent of the patients reported symptomatic improvement, and 94% were improved, as demonstrated by repeat laparoscopy or laparatomy. After completing a course of danazol therapy, 57% of the patients underwent conservative laparotomy for fertility enhancement, pain control, or ovarian masses. Two patients underwent total abdominal hysterectomy-bilateral salpingo-oophorectomy for advanced disease poorly responsive to danazol therapy. In those patients desiring fertility (56), there were 38 pregnancies in 26 women, for an overall fertility rate of 46%. The overall recurrence rate was 33%, as determined by symptoms and physical findings. Significant side effects from danazol were reported by 85% of the patients. The major side effects were weight gain, edema, decrease in breast size, oily skin, hirsutism, and deepening of the voice. Only one patient discontinued danazol therapy due to side effects. Clinical tissues concerning the use of danazol with or without surgery and the miscarriage rate following danazol therapy are discussed.

Abortion, Spontaneous↗
PubMed1982

Medicinal arsenic and internal malignancies.

A mortality analysis has been carried out on a cohort of patients given Fowler's solution (potassium arsenite) for periods ranging from 2 weeks to 12 years between 1945 and 1969. An excess of fatal and non-fatal skin cancer was apparent, but there was no overall excess mortality from cancer. Further analyses by site of cancer, dose level, and time from first exposure are also presented. A subset of patients were examined in 1969-70 for the presence of arsenical keratoses, hyperpigmentation and skin cancer. About half the patients had one or more of these signs. Although the cancer mortality of this entire subgroup was similar to the expected value, all the cancer deaths occurred in patients with prior signs of arsenicism. These data suggest that while any excess of internal malignancy due to the use of Fowler's solution is small or non-existent, there may be a susceptible subgroup which can be identified from dermatological manifestations.

Adult↗
PubMed1982

Assessment of glucose turnover in normal man with the use of a non-radioactive isotopically labelled preparation, [6,6-2H]glucose, as tracer.

1. Glucose kinetics were assessed in seven normal adult male subjects by an intravenous bolus technique with the use of a non-radioactive isotopically labelled preparation, [6,6-2H]glucose, as tracer. Tracer enrichment in plasma was assessed by gas chromatography-mass spectrometry. For comparison five subjects also received a simultaneous intravenous bolus of [6-3H]glucose and kinetics were assessed by conventional means. 2. Administration of [6,6-2H]glucose did not alter circulating glucose or insulin concentrations. 3. Glucose turnover, assessed by the use of [6,6-2H]glucose, was 11.4 (+/- 0.9) micromol min-1 kg-1 and 11.6 (+/- 0.5) micromol min-1 kg-1 with rate of glucose was 2.3 (+/- 0.3) ml min-1 kg-1 with both isotopically labelled tracers. Estimates of mean residence time, glucose pool and glucose space were also similar by each technique. 4. [6,6-2H]Glucose is therefore an effective tracer and allows investigation of glucose kinetics without administration of a radioactive label.

Adult↗
PubMed1982

Visual defects in children of low birthweight.

The prevalence of visual defects at ages 7 to 9 in 1485 children of birthweight 2000 g or less is reported. These children were born in 1970, 1971, and 1973 to parents resident in what is now the South East Thames Regional Health Authority area, and comprise 73.9% of all survivors of births of this weight, 81% of those whose present address is known. Only 16 (1%) children were reported to have serious visual defects; 5 had retrolental fibroplasia. For the children attending normal schools there was a significant excess of both mild and more severe visual defects compared with matched controls. A distant visual acuity of 6/6 was reported in the better eye of 89%, and in both eyes of 83% of the low birthweight group.

Cataract↗
PubMed1982

Prediction of outcome in neonates using EEG.

To determine the value of EEG in predicting prognosis, the recordings of 30 neonates were re-examined using a specially devised method of visual rating which permitted quantitative assessment of 13 EEG items. Seven clinical variables were also coded. The data were submitted to computer discriminant function analysis, to determine whether the outcome could be predicted and which EEG variables contributed most effectively. Marked asymmetries, many slow transients, and a wide range of variability of suppression durations were the main indicators. The state of consciousness during the recording and the gestational age were the clinical variables which were useful. It was possible to predict outcome using this technique in 28 of the 30 patients. The same procedure was applied to serial recordings with equal value. The combination of visual ratings carried out, without reference to clinical information and requiring no subjective statement as to normality or abnormality of the features in the recording, seems to offer a contribution in the difficult field of neonatal EEG.

Electroencephalography↗
PubMed1982

Radial partition immunoassay.

In radial partition immunoassay, radial chromatography is used for performing an immunoassay. We describe the application of this technology to the measurement of digoxin in serum by enzyme immunoassay, with the entire testing procedure carried out on glass-fiber filter paper. A sample is applied to a small central area of the filter paper, where it reacts with the antibody to digoxin immobilized there. Subsequently, enzyme-labeled digoxin is applied to react with remaining antibody sites. After incubation, substrate for the enzyme is applied to the center of the reaction area and washes out any unbound label to the periphery of the paper. This step also initiates the enzyme reaction, which is quantified by front-surface fluorescence. A microprocessor-controlled automated instrument has been developed to process the filter paper matrix through the above sequence, and calculate the final result. Total testing time for digoxin is less than 7 min.

Antibodies↗