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Biomedical subjects

J Sutton

Publications and source records attributed to J Sutton.

At least 73 records · Page 4Linked to original sources
PubMed1989

Morphometric diagnosis of serous effusions: refinement of differences between benign and malignant cases by use of outlying values and larger sample size.

Fifty cytologically malignant, five suspicious, and 27 cytologically benign serous effusions were assessed morphometrically for differences in mean and outlying nuclear and cytoplasmic variables. Significant differences were found between benign and malignant specimens for all nuclear morphometric variables measured, the most significant being largest nuclear area and diameter. No significant differences were found for cytoplasmic size variables. Although measurement of outlying values in serous effusions enhanced the difference between benign and malignant cell populations, it was of insufficient sensitivity or specificity to be of clinical diagnostic use. Increasing the sample size improved test performance but would be tedious to perform manually.

Ascitic Fluid↗
PubMed1989

Ayre v Aylesbury cervical spatulas.

A single blind crossover study compared the traditional Ayre spatula with the new Aylesbury spatula. The study group consisted of all women attending the department of genitourinary medicine during a 16 month period. The same incidence (3.6%) of dyskaryotic smears was found using the Ayre spatula (74/2077) as the Aylesbury spatula (72/2003). The incidence of smears with endocervical cells, however, was significantly greater using the Aylesbury (33.4%) than the Ayre (20.4%) spatulas, despite there being no difference in the incidence of smears with epithelial abnormalities. Quantitative studies thus showed that the Aylesbury gave no more accurate results than the Ayre spatula.

Adolescent↗
PubMed1989

Operation Everest II: muscle energetics during maximal exhaustive exercise.

To investigate the metabolic basis for the reduction in peak blood lactate concentration that occurs with maximal exercise after acclimatization to altitude, eight male subjects [maximal O2 uptake of 51.2 +/- 3.0 (SE) ml.kg-1.min-1] were acclimated to progressive hypobaria over a 40-day period. Before decompression (SL-1), at 380 and 282 Torr, and on return to sea level (SL-2) the subjects performed progressive cycle exercise to exhaustion. Analysis of muscle samples obtained from the vastus lateralis before exercise and at exhaustion indicated a pronounced reduction (P less than 0.05) in muscle lactate concentration (mmol/kg dry wt) at 282 Torr (39.2 +/- 11) compared with SL-1 (113 +/- 9.7), 380 Torr (94.6 +/- 18), and SL-2 (92.7 +/- 22). For the other glycolytic intermediates studied (glucose 1-phosphate, glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, and pyruvate) only the increase in glucose 1-phosphate, glucose 6-phosphate, and fructose 6-phosphate were blunted (P less than 0.05) at 282 Torr. The reduction in muscle glycogen concentration during exercise was similar (P less than 0.05) for all environmental conditions. Although exercise resulted in reductions (P less than 0.05) in ATP and creatine phosphate averaging 30 and 51%, respectively, the magnitude of the change was not dependent on the degree of hypobaria. Inosine monophosphate was elevated (P less than 0.05) approximately 11-fold with exercise at both SL-1 and SL-2. These findings support the hypothesis that the lower lactate concentration observed at 282 Torr after exhaustive exercise is due to a reduction in anaerobic glycolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1987

Operation Everest II: coagulation system during prolonged decompression to 282 Torr.

Thromboembolic phenomena may occur as humans ascend to high altitude. To investigate the role of the coagulation cascade and its inhibitors in these disorders, venous blood was obtained from eight subjects who participated in the Operation Everest II project. Samples were obtained before and 5 min after completion of a progressive incremental exercise test to exhaustion at sea level and atmospheric pressures of 380 (18,000 ft) and 282 Torr (25,000 ft). Plasma was analyzed for the activity or concentration of factors II, V, VII, VIII complex, IX-XIII, prekallikrein, high-molecular-weight kininogen, fibrinogen, antithrombin III, alpha 2-macroglobulin, alpha 2-antiplasmin, C1-esterase inhibitor, alpha 1-antitrypsin, and protein C. Prolonged exposure to simulated high altitude did not alter the concentration of any of the coagulation factors or inhibitors. Exercise increased the circulating concentrations of the factor VIII complex at sea level, 380, and 282 Torr. However, the increment was less at the simulated high altitudes. The increase in the factor VIII complex was inversely related to arterial O2 saturation and directly related to the work load achieved and blood pH and plasma lactate concentrations. These studies suggest that the gradual development of marked chronic hypoxia does not affect the coagulation cascade.

Adult↗
PubMed1985

A morphometric study of submandibular salivary gland changes in streptozotocin-induced diabetic rats.

The morphology of the glands in 9 male rats was studied after 3 months of streptozotocin-induced diabetes mellitus and compared with that of 9 control rats and 6 streptozotocin-treated, non-diabetic rats which served as controls for any effect of streptozotocin not due to diabetes mellitus. In the diabetic group, mean salivary-gland weight and volume was reduced. There was an increase in the ratio of mean volume to total gland volume for seromucous acini (p less than 0.01), intra-lobular striated ducts (p less than 0.001), fat (p less than 0.001) and blood vessels (p less than 0.01), and a decrease in both granular duct (p less than 0.001) and intercalated duct (p less than 0.01) volume ratios. There was a marked reduction in the total length of granular ducts (p less than 0.001) and an increase in the length of striated ducts (p less than 0.001). Measurements from the streptozotocin-treated, non-diabetic group did not differ significantly from those of controls. These effects may be attributable to failure of growth and chronic sodium depletion.

Animals↗
PubMed1984

Kinetic and e.p.r. studies of cyanide and azide binding to the copper sites of dopamine (3,4-dihydroxyphenethylamine) beta-mono-oxygenase.

The kinetics of inhibition of dopamine (3,4-dihydroxyphenethylamine) beta-mono-oxygenase by cyanide (CN-) and azide (N3-) ions have been investigated by using steady-state methods. Both anions show complex non-competitive-inhibition patterns with respect to ascorbate, suggestive of anion binding at two different sites on the oxidized enzyme. To further investigate this finding, e.p.r. titrations of CN- and N3- binding to the 63Cu-reconstituted enzyme were carried out. Addition of approx. 2 equiv. of CN- to copper elicits a new signal with g = 2.217, g = 2.025, A = 17.0 mT characteristic of a copper (II)-cyano complex. Simulations show that this signal accounts for half the copper (II) in the enzyme. The remainder of the enzyme-bound copper is expressed by a signal close to, but not identical with, that of native enzyme. Further addition of CN- induces a simultaneous decrease in intensity of both of these signals so that their 1:1 ratio is maintained. Binding of N3-, on the other hand, changes the e.p.r. spectrum to a form different from either that of the native or CN- -treated enzyme, and integrates to 100% of the copper in the enzyme (g = 2.252, g = 2.050, A = 16.5 mT). Resolved superhyperfine structure is apparent in the g region. N3- binding is also accompanied by the appearance of a broad charge-transfer band centred at 387 nm. Neither 9 nor 35 GHz e.p.r. spectra show evidence for more than one (non-interacting) species of Cu(II) in native enzyme and N3- derivatives. The binding and reactivity of CN-, on the other hand, argues against independent copper sites in the enzyme.

Ascorbic Acid↗
PubMed1984

The effects of cleavage of the inter-chain disulphide bonds of rabbit IgG on its ability to bind C1q.

Immune complexes prepared from rabbit anti-ovalbumin IgG in which the interchain disulphide bonds had been reduced and then blocked with N-( iodoacetylaminoethyl )-8-naphthylamine-1-sulphonic acid retained the ability to bind 125I-labelled C1q. This ability was lost when a small alkylating agent (iodoacetamide) was used to block the cleaved disulphide bonds. The ability of the IgG to form insoluble immune complexes was partially compromised when iodoacetamide was used to block the disulphide bonds, but was unimpaired when N-( iodoacetylaminoethyl )-8-naphthylamine-1-sulphonic acid was used. These data are consistent with the suggestion that access to the C1q binding site in IgG in immune complexes is modulated by movement of the Fab arms, which may block access to the site.

Antigen-Antibody Complex↗
PubMed1984

The role of opioid peptides in the hormonal responses to acute exercise in man.

Opioid involvement in the physiological and hormonal responses to acute exercise was investigated in six normal male subjects. Each was exercised to 40% (mild exercise) and 80% (severe exercise) of his previously determined maximal oxygen consumption on two occasions, with and without an infusion of high-dose naloxone. The exercise task was a bicycle ergometer; mild and severe exercise were performed for 20 min each, followed by a recovery period. Exercise produced the expected increases in heart rate, blood pressure, ventilation, tidal volume, respiratory rate, oxygen consumption and carbon dioxide production. After severe exercise, naloxone infusion increased ventilation from 94.8 +/- 4.9 litres/min to 105.7 +/- 5.0 litres/min (P less than 0.05), but had no effect on any of the other physiological variables. Exercise-induced changes in several hormones and metabolites were noted, including elevations in circulating lactate, growth hormone (GH), prolactin, cortisol, luteinizing hormone (LH), follicle stimulating hormone (FSH), adrenaline noradrenaline, plasma renin activity (PRA) and aldosterone. There was no change in plasma met-enkephalin. Naloxone infusion produced the expected increases in LH and cortisol, but also significantly enhanced the elevations in prolactin, adrenaline, noradrenaline, plasma renin activity and aldosterone (P less than 0.05). Psychological questionnaires revealed minor mood changes after exercise, but no evidence was found for the suggested 'high' or euphoria of exercise. Effort was perceived as greater during the naloxone infusion than the saline infusion in every subject.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Spinal cord ischemia following surgery for aortoiliac occlusive disease.

A 70-year-old man had aortobifemoral bypass for severe aortoiliac occlusive disease. He developed spinal cord ischemia with anterior spinal artery syndrome. He had minimal recovery of muscle function, multiple postoperative complications, and 11 months postoperatively he died. Spinal cord ischemia is a rare and unpredictable complication of abdominal aortic surgery. It most often has occurred following surgery for aneurysm but can also occur after apparently routine surgery for occlusive disease.

Aged↗
PubMed1984

Renal handling of urate during water immersion in the nephrotic syndrome.

Renal handling of urate was examined in 11 patients with nephrotic syndrome before, during, and after 4 h of water immersion up to the neck. Urinary urate excretion, urate clearance, and fractional excretion of urate all increased significantly during water immersion, and decreased in the hour following water immersion. During water immersion fractional excretion of urate rose to a maximum of 16 ml/ml of glomerular filtrate, and fell towards control levels on removal from the bath. It is concluded that either there is a decrease in proximal tubular urate reabsorption or secretion caused by water immersion. In contrast, diurnal control studies showed no significant change in fractional excretion of urate during the same period of the day. It is postulated that the increased fractional excretion of urate on water immersion is due to hypervolemia induced by the hydrostatic pressure of the water on the lower limbs and abdomen.

Adolescent↗
PubMed1981

Renal salt and water handling in water immersion in the nephrotic syndrome.

1. Eleven nephrotic patients were immersed up to the neck in 1.3 m of water at 34 degrees C for 4 h. 2. A diuresis began, within the first hour of, and continued throughout, immersion. The urine osmolality fell significantly and decreased to hypotonic levels in the first hour of immersion and increased gradually during the remainder of immersion and postimmersion. 3. Throughout immersion there was a steady increase in urinary sodium and chloride excretion and a sharp fall in the postimmersion hour. 4. Overall fractional excretion of sodium and of chloride increased steadily throughout immersion and fell during the post-immersion hour. 5. There was an increase in urinary potassium excretion on immersion but no change in fractional excretion of potassium. There was an initial increase in distally reabsorbed sodium/chloride on immersion, as expressed by positive values of CH2O in the first hour of immersion. 6. Plasma aldosterone levels were initially elevated in only two out of nine patients. There was a significant fall in plasma aldosterone levels on immersion, but there was no correlation between sodium/chloride handling and aldosterone levels on immersion.

Adolescent↗
PubMed1981

Simultaneous detection of deuterium oxide and indocyanine green in flowing blood.

A spectrophotometer designed to measure simultaneously traces of deuterium oxide (12 mg.1-) and indocyanine green (0.12 mg.1-1) in flowing blood is described. Its symmetrical four-beam design enabled direct readings in optical density units to be obtained in the infrared region without interference due to atmospheric CO2 and water. This system was validated by the measures of pulmonary extravascular water in the rat in heart-lung preparations and in whole animals. An example of its application showed that, with this system, it was possible to evaluate correctly an alloxan edema in the rat a short time (105 min) after its induction. In these experiments lung water calculated by indicator curves represented 80% of the lung water content (r = 085, n = 10).

Animals↗
PubMed1980

Changes in pulmonary PV characteristics of human subjects at an altitude of 5,366 m.

We measured lung mechanics in seven young adults at 90 m and again after 9-30 days of exposure to 5,366 m on the summit plateau of Mt. Logan. Increases in peak expiratory flow (by 20%, P less than 0.05) and decreases in total pulmonary resistance (by 30%, P less than 0.02) were consistent with the reduced gas density at high altitude. However, forced expiratory volume in 1 s decreased in four of the seven subjects, suggesting an increase in resistance of small airways or decrease in lung recoil associated with hypoxia. Increase in total lung capacity (TLC), as measured by helium dilution, occurred in each subject and by over 2 liters in two of the subjects (mean increase 17.9%, P less than 0.01). With the increased TLC's taken into account, there were still leftward shifts in the static expiratory pressure-volume (PV) curves with abnormally low lung recoil at 60% TLC, accounting for disproportionately large increases in residual volume (RV/TLC increased from 0.31 to 0.44, P less than 0.005). Prolonged exposure to high altitude is associated with increases in lung volume and shifts in PV curves indistinguishable from those previously described during exercise-induced asthma and during acute isocapnic hypoxia.

Adult↗
PubMed1977

Measurement of postoperative pericardial pressure in man.

Pericardial pressure was measured in 18 patients undergoing cardiopulmonary bypass for up to 10 days using a solid state transducer. Mean and phasic pericardial pressure wave forms were similar to those reported in animals. A wide range of mean pressure from 0 to 30 mmHg was recorded, and values of up to 20 mmHg were observed in patients whose postoperative clinical course was uncomplicated. Fluctuations in pericardial pressure during spontaneous and artificial respiration were small, suggesting that concomitant left ventricular diastolic pressure changes were mainly the result of alterations in diastolic filling. Relative ventricular and pericardial distensibilities were estimated from the ratio of the slopes of diastolic pressure with time, which showed that up to 25 per cent of left ventricular diastolic pressure was supported by the pericardium and 75 per cent by the myocardium. Measurement of pericardial pressure had clinical value in 2 patients in confirming and excluding the presence of pericardial tamponade.

Adolescent↗