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Biomedical subjects

A Rutherford

Publications and source records attributed to A Rutherford.

At least 19 recordsLinked to original sources
PubMed1995

Allelic drop-out and preferential amplification in single cells and human blastomeres: implications for preimplantation diagnosis of sex and cystic fibrosis.

Previously the diagnosis of sex and cystic fibrosis status has been studied on single cells using the polymerase chain reaction (PCR). It has been suggested that allelic drop-out (PCR failure of one allele) and/or preferential amplification (hypo-amplification of one allele) may contribute to poor reliability and misdiagnosis, although this remains controversial as some reports suggest that allelic drop-out does not occur. We investigated an improved method of diagnosing sex and cystic fibrosis in single cells using a new technology (fluorescent PCR) to determine the base level of PCR artefacts (allelic drop-out and preferential amplification) which, in combination with improved sensitivity, should improve PCR reliability and accuracy. Fluorescent PCR gives high reliability (approximately 97%) and accuracy rates (approximately 97%) in somatic cells for both sex and cystic fibrosis diagnosis and its lower detection threshold allows allelic drop-out and preferential amplification to be easily distinguished. We also achieved high reliability and accuracy in diagnosing cystic fibrosis in human blastomeres. This study confirms earlier reports of both allelic drop-out and preferential amplification in single cell analysis. We demonstrate that both allelic drop-out and preferential amplification occur in somatic cells and suggest these are separate phenomena. Preferential amplification appeared common in single cell PCR while allelic drop-out apparently occurred at random in each allele. Preferential amplification was mainly amplification of the larger allele. We suggest that some inaccuracy/misdiagnosis may be due to both preferential amplification as well as allelic drop-out. Other findings were variability in drop-out between PCR and that amplification of signals from human blastomeres may be linked to embryo quality. We suggest that allelic drop-out is dependent on the number of cells within the sample.

Alleles↗
PubMed1992

Activation of Bacillus subtilis transcription factor sigma B by a regulatory pathway responsive to stationary-phase signals.

Alternative transcription factor sigma B of Bacillus subtilis controls a stationary-phase regulon induced under growth conditions that do not favor sporulation. Little is known about the metabolic signals and protein factors regulating the activity of sigma B. The operon containing the sigma B structural gene has the gene order orfV-orfW-sigB-rsbX, and operon expression is autoregulated positively by sigma B and negatively by the rsbX product (rsbX = regulator of sigma B). To establish the roles of the orfV and orfW products, orfV and orfW null and missense mutations were constructed and tested for their effects on expression of the sigma B-dependent genes ctc and csbA. These mutations were tested in two contexts: in the first, the sigB operon was under control of its wild-type, sigma B-dependent promoter, and in the second, the sigB operon promoter was replaced by the inducible Pspac promoter. The principal findings are that (i) the orfV (now called rsbV) product is a positive regulator of sigma B-dependent gene expression; (ii) the orfW (now called rsbW) product is a negative regultor of such expression; (iii) sigma B is inactive during logarithmic growth unless the rsbW product is absent; (iv) the rsbX, rsbV, and rsbW products have a hierarchical order of action; and (v) both the rsbV and rsbW products appear to regulate sigma B activity posttranslationally. There are likely to be at least two routes by which information can enter the system to regulate sigma B: via the rsbX product, and via the rsbV and rsbW products.

Amino Acid Sequence↗
PubMed1991

A comparison of rectal indomethacin with placebo for pain relief following spinal surgery.

Rectal indomethacin was compared with placebo in a randomised, double-blind study of 100 patients undergoing spinal surgery, in which postoperative pain scores, pethidine, diazepam and metoclopramide consumption, bleeding time, blood loss and oral fluid and food tolerance were measured. Side-effects of indomethacin and pethidine were compared in the two groups. In the indomethacin group, pain scores were significantly less for all measurements made during the first three postoperative days, pethidine and diazepam consumption were significantly less on all three days, bleeding time was significantly increased, although still within the clinically normal range, intraoperative and postoperative blood losses were not significantly affected, coagulation was not significantly impaired as assessed clinically, patients tolerated oral feeding significantly earlier, there was no significant increase in the incidence of gastro-intestinal side-effects except for diarrhoea, and there was no significant reduction in the incidence of side-effects associated with the use of pethidine.

Administration, Rectal↗
PubMed1990

Evaluation of hip pain following cemented total hip arthroplasty.

The occurrence of pain following a technically satisfactory cemented total hip arthroplasty is of concern for both the orthopedic surgeon and the patient. In order that the source of the pain be accurately located, a scientific approach is required. We present an algorithm for the evaluation of pain following an apparently satisfactory hip arthroplasty which, if followed, results in the correct diagnosis.

Arthrography↗
PubMed1989

The geometry of the muscles of the lumbar spine determined by magnetic resonance imaging.

Magnetic Resonance Imaging (MRI) is a new multiplanar imaging technique that clearly demonstrates soft tissue anatomy. The lumbar spines of 26 males have been scanned. From the transverse scans, the position and cross-sectional areas of the muscles of the lumbar region were recorded. Regression analysis was performed to relate these values to trunk measurements and body weight. Sagittal scans were used to measure the angles to the vertical of the lumbar discs and of the skin overlying the spinous processes. The position of each lumbar disc relative to two skin points was measured. These parameters can then be used in biochemical calculations of low-back forces.

Adolescent↗
PubMed1988

An afterhyperpolarization recorded in striatal cells 'in vitro': effect of dopamine administration.

Parahorizontal slices of the neostriatum from young adult male rats were maintained at the fluid interface of a perfusion chamber. Intracellular recordings were made with potassium acetate filled micropipettes. The mean resting membrane potential of the neurones was -84 mV and all produced action potentials which overshot 0 mV. All the cells were silent at resting membrane potentials and only fired in response to depolarizing pulses delivered through the intracellular electrode. When long pulses were applied, the firing rate within the train of action potentials evoked was slower at the end of the pulse. In a very few cells at resting membrane potential, but in all cells depolarised from a holding potential of -65 mV, the resulting train of action potentials was followed by a slow hyperpolarizing potential. The potential observed was smaller in amplitude than the afterhyperpolarization seen in hippocampal pyramidal cells in vitro, but its voltage sensitivity was similar. Iontophoresis of dopamine (DA) close to the recording pipette resulted in two distinct actions. Firstly, DA reduced the number of action potentials following a short pulse, by increasing the threshold for spike initiation. Secondly, it also inhibited the hyperpolarizing potential which followed trains of action potentials even when allowance was made for the increased firing threshold. The inhibition of this hyperpolarization was accompanied by an increase in the number of spikes per pulse. Whether these two actions of DA are mediated by a single receptor/membrane action is unclear. Nevertheless, they may help to reconcile the contradictory literature regarding the action of DA upon extra-cellular responses in striatal cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

Electrophysiological demonstration of host cortical inputs to striatal grafts.

Adult rats received a unilateral injection of ibotenic acid into the striatum, resulting in an extensive loss of intrinsic striatal neurones. Transplanted striatal cells from embryonic day 14 rat foetuses grew well in the damaged tissue and approximately 6 months later brain slices were cut in such a way as to include the grafts and nearby cortical tissue. Electrophysiological recordings from the grafts showed typical extracellular responses to stimulation of the subcortical white matter. Thresholds and latencies for responses were similar in grafted and control striatum. The grafted cells, however, appeared to be subject to less collateral inhibitory control than normal striatal neurones. The similarities between the responses of grafted neurones and those in normal striatum suggest that corticostriatal connections reform after transplantation, which may be an important component in the behavioural recovery observed in similar animals.

Animals↗
PubMed1985

Fractures of the lateral humeral condyle in children.

I conducted a clinical review of thirty-nine fractures of the lateral condyle of the humerus in children and drew the following conclusions: (1) epiphyseal arrest is rare (it occurred in only one patient, despite malreduction in ten), and (2) fishtail deformity of the distal part of the humerus occurs commonly when malreduction is present. Only two poor results were encountered, both in patients in whom the reduction was grossly inadequate.

Adolescent↗
PubMed1983

Osteomyelitis of the symphysis pubis.

A case of osteomyelitis of the symphysis pubis caused by Streptococcus agalactiae with no identifiable predisposing factors is presented. The differentiation from osteitis pubis and the causative organism are discussed.

Female↗
PubMed1983

Footprints.

Explore the source record for details and available documents.

Child↗
PubMed1981

Stereophotogrammetry and relief photography in the assessment of foot disorders.

Expanded polyethylene foam (Plastazote) is used in the treatment of rheumatoid, diabetic, and leprotic foot disorders. This paper describes a diagnostic use for this material. Two photographic techniques combine to give vivid and quantitative representations of foot deformities which are easily applicable to clinical use. Relief photography uses illumination to create an illusion of solidity in a 2-dimensional photography. Stereophotogrammetry produces contour plots from stereopairs of photographs of the Plastazote footprint. After use the impressions are trimmed and slipped into the patient's shoes in the same way as any other foam insole.

Dermatoglyphics↗
PubMed1979

Should recurrent calcium oxalate stone formers become vegetarians?

The hypothesis that the incidence of calcium stone disease is related to the consumption of animal protein has been examined. Within the male population, recurrent idiopathic stone formers consumed more animal protein than did normal subjects. Single stone formers had animal protein intakes intermediate between those of normal men and those of recurrent stone formers. A high animal protein intake caused a significant increase in the urinary excretion of calcium, oxalate and uric acid, 3 of the 6 main urinary risk factors for calcium stone formation. The overall relative probability of forming stones, calculated from the combination of the 6 main urinary risk factors, was markedly increased by a high animal protein diet. Conversely, a low animal protein intake, such as taken by vegetarians, was associated with a low excretion of calcium, oxalate and uric acid and a low relative probability of forming stones.

Calcium↗
PubMed1979

Urinary tract stone disease.

Patients suffering from urinary stone are traditionally referred to a surgeon. Most are investigated only as far as establishing the site of the stone and its effect on renal function. Although a number of patients may require surgery, the majority pass the stone spontaneously and are discharged within a few days. If the patient has a recurrence, as most eventually have, it is not routine practice to establish the type of stone, screen for underlying disease, identify the urinary abnormalities or to institute preventive medical treatment. Although it was considered that surgery itself had something to offer in reducing the recurrence rate this is no longer generally held except in infected stone disease. Nevertheless it is still uncommon to involve a physician, and in particular a nephrologist, in the investigation and management of urinary stone-formers. Urinary stone disease still remains, to a large extent, outside the field of nephrology.

Bacterial Infections↗
PubMed1978

Neuronal and non-neuronal components in the overflow of labelled adenyl compounds from guinea-pig taenia coli.

Guinea-pig taenia coli preprations were pre-incubated in 3H-adenosine and the overflow of 3H-compounds to a superfusing medium was measured during transmural field stimulation in the presence and absence of tetrodotoxin. The fractional overflow of 3H-compounds on stimulation of taenia coli pre-incubated in 3H-adenosine at 10(-7) M was greater than after incubation at 10(-5) M. About half of the releasable store was blocked by tetrodotoxin. It is proposed that at lower concentrations, there is selective loading of a releasable store, while at higher concentrations thare is a greater loading of non-releasable stores, and that neuronal stores account for about 33% of the 3H-compounds released by transmural stimulation.

Adenosine↗