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Biomedical subjects

K Hughes

Publications and source records attributed to K Hughes.

At least 145 records · Page 8Linked to original sources
PubMed1985

Hormones, ionic regulation and kidney function in fishes.

Renal osmoregulatory mechanisms in the context of hormones is considered in three types of fish: the Agnatha, the Chondrichthyes and the Osteichthyes. Particular reference is made to endocrine status and hormonal interplay in renal homeostatic mechanisms. Among Agnatha, hagfishes display atypical osmoregulatory characteristics and their endocrine repertoire is poorly understood. Hormonal actions are unclear although the kidney appears to act as a regulator of extracellular fluid volume. Lampreys show many similarities with teleost fish with respect to osmoregulation, but again their endocrine system requires further definition. Chondricthyean fishes have a number of unique hormones, among them 1-alpha-hydroxycorticosterone from the adrenocortical homologue (interrenal gland). Their complex kidneys have not been extensively studied with respect to hormonal regulation, but a key role is certainly the maintenance of high plasma levels of urea and trimethylamine oxide. The importance of the ratio of these two compounds with respect to urea tolerance is discussed. Evidence is presented and discussed that points to 1-alpha-hydroxycorticosterone playing a role in osmoregulation, although its sites and mechanisms of action are not known. The presence of a non-hypophysial control of interrenal function (a renin-angiotensin system) is indicated. The largest group of fishes, the Teleostei, are considered with respect to renal mechanisms involved in euryhalinity. Highly selective reference is made to the renin-angiotensin system and arginine vasotocin. In fresh water eels a clear negative feedback relationship exists between angiotensin II and arginine vasotocin, while in seawater-adapted animals the interplay is less clear. It is suggested that the observed increases in both arginine vasotocin and angiotensin II in eels adapted to environments hyperosmotic to their extracellular fluid in some way affects the "setting" of the feedback between the two. The possible interactions with other hormones is considered in outline.

Angiotensins↗
PubMed1984

Low birthweight of live singletons in Singapore, 1967-1974.

A random sample of 23 591 single livebirths was drawn from the Singapore Registry for 1967-1974, and information extracted from the birth certificates. The proportion of low birthweight infants (2500 g or less) fell markedly from 9.1% in 1967 to 5.7% in 1974, which has not been the finding in other studies. Variation in the proportions of low birthweight infants by sex, maternal age, parity, and social class, are broadly in agreement with other studies. Indians were found to have significantly smaller babies (mean weight of 3020 g) with a higher proportion of low birthweight ones (11.5%) than the Malays (3080 g and 8.1%) and the Chinese (3130 g and 6.1%). This is despite similar distributions of gestational age, and for term babies the differences in low birthweight proportions are highly significant with Chinese 5.0%, Malays 6.5%, and Indians 9.8%. The reasons for this are discussed with the implication that lower birthweights in Indians are to some extent of ethnic/genetic origin.

Adult↗
PubMed1983

Chimeric plasmid that replicates autonomously in both Escherichia coli and Neurospora crassa.

A hybrid pBR322 plasmid (designated pDV1001) containing two functional Escherichia coli antibiotic resistance genes (kanr and camr) and a qa-2+ gene from Neurospora crassa transforms N. crassa qa-2- mutants to qa-2+ with a frequency of ca. 5 X 10(-5) per regenerated spheroplast (ca. 100 transformants per microgram of plasmid DNA). This plasmid can replicate autonomously without integrating into the N. crassa genome. The autonomously replicating hybrid plasmid was detected in N. crassa transformants by Southern gel hybridizations. DNA from these transformants can be recovered by retransformation back into E. coli aroD recipients and selection for chloramphenicol resistance. These E. coli transformants complement an aroD mutant. The hybrid plasmid DNA present in the E. coli transformants remains unchanged on the basis of DNA restriction enzyme analyses. The original, nonhomokaryotic N. crassa transformants can be maintained on a selective medium, but there is as yet no evidence that the self-replicating plasmid can be transmitted through meiosis. In addition, the self-replicating plasmid often integrates into the N. crassa genome and then is inherited in a generally stable fashion through meiosis. Our findings suggest that this plasmid, or some derivative of it, will prove useful as a routine shuttle vector for cloning genes in N. crassa.

Cloning, Molecular↗
PubMed1982

Duodeno-gastric reflux in normal and dyspeptic subjects.

A simple radiological technique is described for detecting the presence, or absence, of duodeno-gastric reflux (DGR) at barium meal examination. The incidence of DGR was found to be approximately the same in both normal volunteers and dyspeptic patients. Although there was a slight trend towards an increased incidence in gastric ulcer, this did not reach statistical significance. The severity of reflux did not correlate with the presence of peptic ulceration. DGR appears to be more common with increasing age. Our results cast doubt on the hypothesis that reflux of duodenal content plays a primary role in the pathogenesis of gastric ulcer.

Adolescent↗
PubMed1981

Effects of demand for performance, self-monitoring of arousal, and increased sympathetic nervous system activity on male erectile response.

Clinical programs for the treatment of impotence generally have been successful but without experimental verification of their individual components or factors associated with the development of impotence. Twenty-four normal males participated in an investigation comparing factors believed to inhibit or facilitate penile tumescence. The effects of demand for performance, self-monitoring of erection, and increased SNS activity, were evaluated. Subjects were exposed to sexual stimuli under these conditions and measurements of penile responses were taken. Results indicated that there were no differential effects on penile responses between demand and no-demand or between self-monitoring and no self-monitoring. Increased SNS activity appeared to facilitate loss of erection, but only after, and not during, the sexual stimulus. The clinical and theoretical implications of these findings are discussed, and suggestions are made for future research.

Adult↗
PubMed1980

Prevention of early failure of stapled gastric partitions in treatment of morbid obesity.

Clinical observations and data obtained in animal experiments indicate that the gastric partition is most susceptible to the stresses of solid food boluses between the second and sixth postoperative weeks, predisposing the operation to early failure. Tensiometer studies indicate that by the sixth to the eighth postoperative week, the staple line is as strong as uninjured stomach. Liquid diet restriction for eight weeks after gastric partitioning reduces the incidence of early operative failure. Until safe and effective methods of increasing staple line strength are established, all patients having gastric partitioning should be restricted to a liquid diet for eight weeks after operation.

Animals↗
PubMed1980

The radiology of local complications of haemodialysis access devices.

Of the three types of haemodialysis access devices, radiology is of value in demonstrating local vascular complications only in the arteriovenous graft. The local complications are classified as inflow obstruction, false aneurysm and outflow obstruction. A rational angiographic technique is described and the local complications likely to be encountered are illustrated.

Angiography↗
PubMed1980

Smallpox surveillance in Bangladesh: I - Development of surveillance containment strategy.

A major epidemic of Variola major with an estimated 90 000 cases and 18 000 deaths occurred in Bangladesh in 1972. During a 3-year period methods of active surveillance (market search, outbreak investigation, and house-to-house search) were developed to supplement the passive reporting system. The percentage of smallpox cases detected increased from 11.8% in 1972 to 83% in 1975. Together with the implementation of improved methods of outbreak control, smallpox transmission was interrupted in October 1975.

Bangladesh↗
PubMed1980

Smallpox surveillance in Bangladesh: II - Smallpox facial scar survey assessment of surveillance effectiveness.

A smallpox facial scar survey of 465 892 persons aged 0-19 years was carried out in Bangladesh in 1976, covering approximately 1% of the 0-19 year old population. Of the 4 306 persons found with facial scarring consistent with previous smallpox infection, none had a history of smallpox with onset after the last reported case on October 16, 1975. Histories taken from persons with facial scars allowed smallpox incidence to be estimated for each year from 1972 to 1975. These estimates indicate that completeness of reporting increased steadily from 11.8% in 1972 to 83.0% in 1975, reflecting the increasing effectiveness of surveillance.

Adolescent↗
PubMed1974

Experience in monitoring gentamicin therapy during treatment of serious gram-negative sepsis.

This paper reports our experience in monitoring gentamicin therapy during the treatment of 68 episodes of serious Gram-negative sepsis in 65 hospital patients. Most of the patients had major underlying disease. Of those who were adequately treated (peak serum concentrations of 5 mug/ml or more in 72 hours for septicaemia, urinary tract infection, and wound infection; and 8 mug/ml or more at some time during the course of treatment for pneumonia) 84% (46 out of 55) were cured. These serum concentrations could be achieved only by starting with a regimen of 5 mg/kg/day in three divided doses in all adult patients, subsequent dosage being determined by the results of rapid serum assay. The incidence of nephrotoxicity and symptomatic ototoxicity was no greater than in previous series. The main reason for assaying serum gentamicin is to ensure that an adequate dosage is achieved as soon as possible. In patients with impaired renal function or receiving prolonged high dosage assays also serve to guard against an excessive accumulation of gentamicin and an increased risk of toxicity.

Acute Kidney Injury↗