Biomedical subjects
Publications and source records attributed to E A Taylor.
Sixty-two children undergoing cardiac surgery were surveyed for the presence of external jugular veins. When present, these were used as a route for central venous catheterisation using a 'J' wire Seldinger technique. Only 54% of attempted insertions were successful but the results support greater efficacy in older children.
The promotion of growth in infants and young children with chronic renal failure (CRF) requires an aggressive approach to feeding, often in combination with early dialysis. Supplementary feeding has usually involved the use of nasogastric tubes, but these can have many problems. We report our experience with a gastrostomy button device (Bard Ltd.) for long term feeding. Ten children (7 male) had an initial gastrostomy catheter inserted at a median age of 2.0 years (range 0.25-8.5 years). None of the children required an operation for gastrooesophageal reflux and 6 had placement of the gastrostomy catheter at the time of insertion of the Tenckhoff catheter for continuous cycling peritoneal dialysis (CCPD). The catheter is usually exchanged for a similar sized (18 gauge) button device after 4 weeks. All ten children received CCPD in addition to overnight feeding using an enteral feeding pump. The buttons have been in use for a mean of 12 months (range 2-33 months) and are only changed if the anti-reflux valves fail. Nutritional goals have been achieved and growth parameters maintained or improved in 9 children. The button has many advantages over nasogastric tubes or gastrostomy catheters. It has been welcomed by our families in reducing the stress of feeding these young children.
Hyperactive boys between 6 and 8 years of age, identified through systematic population-based screening of a community in London, were compared prospectively with a nonhyperactive control group to determine whether they were at greater risk of sustaining injuries. The study sample was drawn from 1296 completed parent and teacher questionnaires. Hyperactive groups were designated in three ways (parental report, teacher report, and combined parent and teacher report). Injuries were assessed by reviewing the medical records of the five emergency departments serving the community. Although boys with conduct problems did sustain more injuries than control subjects, no relationship between hyperactivity and injury was found. Similarly, when milder injuries were excluded from the analysis, the association remained negative. The absence of an association could not be accounted for by differential parental protectiveness of boys designated hyperactive. This study, which has a power of .80 to determine an increase in the relative risk of injury of 1.5, found no effect for hyperactive behavior in boys. Hyperactive behavior is probably not a risk factor for injury; if it is, it exerts a modest effect, less than 1.5, therefore accounting for less than 4% of injuries to school-aged boys.
To test the hypothesis that there is an abnormal serum insulin response to a carbohydrate load in thyrotoxic hypokalaemic periodic paralysis (THPP), 18 men with THPP and 15 with uncomplicated thyrotoxicosis were studied during an oral glucose tolerance test. The THPP group had significantly higher fasting insulin concentrations (27.6 [3.6] vs 13.4 [1.8] mU/l; p less than 0.005) and a higher overall insulin response to oral glucose (p less than 0.001 by ANOVA) than the thyrotoxicosis group. There were no significant differences in fasting or stimulated glucose. Hyperinsulinaemia may be an important factor in the precipitation of acute paralysis in THPP.
Cultured pig and bovine endothelial cells are capable of synthesizing endothelin-1 (ET-1). Thus the observation that the kidney contains a large number of binding sites for ET distributed in close proximity to endothelial cells suggests that ET-1 may be released from the endothelium to act locally on these receptors. In support of this hypothesis, using the technique of reverse transcription with specific amplification of cDNA, we report here that ET-1 mRNA is expressed in the rat kidney. The partial sequence of the amplified rat ET-1 cDNA confirms that the mature rat peptide is identical to that of the mouse, man and pig, but with some differences in codon usage.
Conventional biochemical and antibiotic sensitivity tests were used to allocate 87 clinical isolates of anaerobic gram-positive cocci to currently recognised species, in comparison with type and other authentic reference strains. Whole-cell protein electrophoresis was then performed with extracts of each strain. Allowing for difficulties of standardisation, it was possible to allocate most of the organisms to species-related groups on the basis of protein patterns. Organisms identified conventionally as Peptostreptococcus anaerobius and P. micros formed homogeneous groups by protein electrophoresis. There was evidence for heterogeneity amongst strains identified as P. asaccharolyticus (two groups, including P. indolicus), P. prevotii and P. magnus. However, aberrant P. prevotii strains were allocated to the P. asaccharolyticus groups, leaving a homogeneous P. prevotii group, and if P. variabilis were re-instated as a species, the remaining P. magnus strains could be divided into two groups. Of the anaerobic gram-positive cocci in the National Collection of Type Cultures deposited by Hare, Group IV is P. magnus, Group IX is P. micros and Groups I, III and VIII appear to be related to the butyrate-producing species P. asaccharolyticus and P. prevotii, but are strongly saccharolytic.
To determine the effects of age, sex, race, and family history of hypertension on cellular cation transport, we measured specific tritiated-ouabain binding (sodium/potassium pump number), and sodium/potassium pump-mediated rubidium-86 uptake in blood lymphocytes from 105 healthy normotensive adults, comprising 23 Chinese and 19 Indian subjects who had first-degree relatives with cryptogenic hypertension, and 40 Chinese and 23 Indian matched subjects without such history. Both Chinese and Indian subjects with family history had significantly fewer sodium/potassium pumps than control subjects. Sodium/potassium pump-mediated rubidium-86 uptake was similar in these four subject groups. Seven Indian patients with untreated cryptogenic hypertension had fewer sodium/potassium pumps than normotensive Indians without family history. Age did not affect sodium/potassium pump numbers in cells from normotensive subjects. In normotensive subjects without family history. Chinese women had more sodium/potassium pumps than Chinese men, but Indian subjects did not show this pattern. We conclude that a family history of cryptogenic hypertension is associated with fewer lymphocyte sodium/potassium pumps than normal. The reduction in cellular pump number might be only a marker, or an epiphenomenon. However, the reduction in pump number might contribute to the pathogenesis of cryptogenic hypertension if it produces sodium retention in renal tubular or peripheral vascular cells.
1. To study potassium transport in hypokalaemic periodic paralysis in a model of striated muscle cells, we measured specific [3H]ouabain binding (the number of sodium-potassium pumps), sodium-potassium-pump-mediated (ouabain-sensitive) 86Rb+ influx and sodium-potassium-pump-independent (ouabain-resistant) 86Rb+ influx in lymphocytes in vitro. 2. The subjects comprised euthyroid and thyrotoxic men with hypokalaemic periodic paralysis between attacks, men with uncomplicated thyrotoxicosis, and healthy men matched for age and weight. 3. Thyrotoxic patients, both with and without periodic paralysis, had significantly more lymphocyte sodium-potassium pumps than normal, and a significantly greater sodium-potassium-pump-mediated 86Rb+ influx. Anti-thyroid treatment corrected this defect in patients with thyrotoxic periodic paralysis. Euthyroid patients with cryptogenic periodic paralysis had significantly increased sodium-potassium-pump-mediated 86Rb+ influx, but a normal number of sodium-potassium pumps. 4. Only untreated thyrotoxic and euthyroid patients with periodic paralysis showed a significant increase in sodium-potassium-pump-independent 86Rb+ influx (5.2 +/- 2.8 and 4.5 +/- 1.8 respectively, vs control 2.8 +/- 1.0 pmol h-1 10(-6) cells; mean +/- SD; P less than 0.001, P less than 0.005). 5. We conclude that thyrotoxicosis increases the number and activity of sodium-potassium pumps and facilitates, but is probably not necessary for, periodic paralysis. Hypokalaemic periodic paralysis is associated with an increase in sodium-potassium-pump-independent potassium influx.
Pregnancy-induced hypertension may be linked with sodium pump inhibition and an increase in vascular myocytic tone and, hence, flow impedance. All of the findings of studies on circulating plasma and blood cells are not, however, consistent with this hypothesis. We therefore assessed sodium pump numbers and cation transport in lymphocytes from 23 women with untreated pregnancy-induced hypertension, 28 normotensive pregnant women and 28 healthy non-pregnant women. We measured the maximum 3H-ouabain binding capacity to determine the sodium pump activity and the apparent dissociation constant (the reciprocal of which estimates binding affinity) by Scatchard analysis, ouabain-sensitive (pump-mediated) 86rubidium influx and ouabain-resistant (pump-independent) influx in lymphocytes in vitro. Pregnant women, whether normotensive or hypertensive, had significantly more sodium pump activity and a higher pump-mediated and pump-independent 86rubidium influx than non-pregnant women. Sodium pump activity and the pump-mediated and pump-independent 86rubidium influx all reached normal, non-pregnant levels in normotensive pregnant women 6 weeks after delivery, but remained high in women with pregnancy-induced hypertension. The normotensive and hypertensive pregnant women and non-pregnant women all had similar ouabain binding affinity. The results of our study do not support the circulating sodium pump inhibitor hypothesis in pregnancy-induced hypertension.
We have measured specific [3H]ouabain binding and ouabain sensitive 86rubidium influx in intact human lymphocytes incubated for up to 7 days in media containing different concentrations of fetal calf serum and human serum. Incubation for periods of up to 7 days with fetal calf serum and human serum produced increases in both specific [3H]ouabain binding and ouabain sensitive 86rubidium influx that were dependent on concentration and time. Neither specific [3H]ouabain binding nor ouabain sensitive 86rubidium influx was altered when dialysed serum was used, suggesting that both fetal calf serum and human serum contain a dialysable factor or factors which stimulate specific [3H]ouabain binding and ouabain sensitive 86rubidium influx in intact human lymphocytes. To further elucidate the mechanisms underlying these changes we also measured the activity of two other enzymes of the lymphocyte plasma membrane, 5'-nucleotidase and gamma-glutamyltransferase, the uptake of [3H]thymidine by the intact cells, and the effects of cycloheximide, puromycin, and anisomycin, inhibitors of protein synthesis. The activity of 5'-nucleotidase was increased after incubation of the lymphocytes in fetal calf serum for 72 h, but the activity of gamma-glutamyltransferase was not changed, suggesting some selectivity of the stimulatory effect. Measurements of [3H]thymidine uptake by the lymphocytes showed that the major part of the observed changes in specific [3H]ouabain binding and ouabain sensitive 86rubidium influx was not attributable to transformation of the lymphocytes to lymphoblasts. All three inhibitors of protein synthesis prevented the increase in specific [3H]ouabain binding due to fetal calf serum.
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To test whether leucocyte sodium pumps function abnormally in patients with essential hypertension specific tritium-ouabain binding (number of pumps) and ouabain sensitive uptake of rubidium-86 (86Rb+) (transport activity) were measured in mononuclear leucocytes from 37 untreated hypertensive patients and 85 normotensive subjects. Ouabain binding was lower and transport activity per binding site higher in the hypertensive patients before incubation (p less than 0.001), but both variables were normal after incubation for 72 hours with fetal calf serum. To determine whether a circulating inhibitor of sodium pumps was present in patients with hypertension ouabain binding and 86Rb+ uptake were measured in normal leucocytes before and after incubation for 72 hours with serum from 13 untreated hypertensive patients and 18 normotensive subjects. Ouabain binding was lower after incubation of cells with serum from hypertensive patients than after incubation with normal serum both before (p less than 0.01) and after (p less than 0.001) dialysis of the serum. The results suggest that in hypertension a circulating serum inhibitor of the sodium pump causes a chronic but reversible reduction in the number of pumps.
A study of the pharmacokinetics of imipenem in 22 patients undergoing elective colorectal surgery was performed. Samples of plasma, fat, muscle and viscera were assayed at various intervals following intravenous injection of 1 g imipenem and 1 g cilastatin. The concentration of imipenem in plasma was approximately ten times that found in the tissues. The half-life was similar in plasma, muscle and fat (approximately 1 h). Visceral levels showed a slower fall (T 1/2 83 min). Plasma and tissue levels exceeded the MIC90 for all common pathogens for at least the first two hours of surgery. We conclude that imipenem is a suitable agent for antibiotic prophylaxis in colorectal surgery.
Severe degrees of inattentive and restless behaviour in childhood are a risk factor for later psychological disorders. They have many causes, but a pattern of severe and pervasive hyperactivity with poor concentration in the absence of affective or psychotic disorders should be recognised as a hyperkinetic syndrome. The syndrome is often associated with developmental delays in abilities such as language and motor control. Powerful short-term treatments are available, but long-term ways of promoting normal personality development need more research.
Fifty-two patients with axillary abscesses were seen during two years. Staphylococcus aureus was isolated from 34, anaerobic bacteria from 12, and skin flora from five; in one case the pus was sterile. Seven patients with hidradenitis suppurativa had recurrent infection with abscess formation, which was bilateral in three. Anaerobes were isolated in five of these cases and skin flora alone in two. Anaerobes are secondary invaders in this condition, and histological examination shows that the primary abnormality is obstruction of pilosebaceous follicles and apocrine glands, associated with keratin plugging of the follicles. Chemotherapy offers little hope of cure, although metronidazole removes the offensive smell of the discharge. Radical surgery is usually indicated.
A double-blind, balanced and randomised study in 8 healthy volunteers examined the effects of relatively high versus low single doses of practolol on heart rate and ventilation at rest and during standardised exercise. Practolol 1 and 4 mg/kg, a typically non-selective drug propranolol 0.2 mg/kg, and placebo were given intravenously at weekly intervals. Cardiac beta-adrenoceptor blockade was measured by the reduction in exercise heart rate greater than 160 beats/min, and bronchial beta-adrenoceptor blockade by the reduction in exercise peak expiratory flow rate (PEFR) up to 4 h after each treatment. Results were assessed by analysis of co-variance. All three active treatments reduced exercise heart rate markedly, practolol 4 mg/kg causing most reduction. Exercise PEFR was significantly reduced by propranolol 0.2 mg/kg compared with both practolol 1 mg/kg and placebo at all times of measurement, and by practolol 4 mg/kg compared with practolol 1 mg/kg and placebo at most times. Mean plasma concentrations after practolol 4 mg/kg were 3.5 to 4.5 times higher than after 1 mg/kg. Practolol may lose its 'cardioselectivity' and cause airflow obstruction at relatively high plasma concentrations above about 2 microgram/ml.
1. The effect of a single oral dose of propranolol on the ventilatory response to hypercapnia has been studied in five healthy subjects. 2. Propranolol produced a small but significant reduction in the slope of the ventilation/end-tidal PCO2 regression line. 3. Propranolol did not significantly change vital capacity or forced expiratory volume in 1 s.