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Biomedical subjects

C R Williams

Publications and source records attributed to C R Williams.

At least 37 records · Page 2Linked to original sources
PubMed1991

Mutations permitting the anaerobic growth of Escherichia coli on trehalose.

Wild-type strains of Escherichia coli K-12 do not grow anaerobically on trehalose or galactose. We isolated two operon fusion mutants of E. coli which gained the ability to grow on trehalose anaerobically (tan). The tanA-lac mutation was located at 41 min on the E. coli genetic map and also abolished growth on glucuronic acid both aerobically and anaerobically. The tanB-lac mutation was mapped to 68 min and permitted anaerobic growth on galactose as well as trehalose. The tanB-lac fusion was induced anaerobically whereas tanA-lac showed more or less constitutive beta-galactosidase expression.

Anaerobiosis↗
PubMed1991

Ultrastructural study of the blood cells of the beluga whale, Delphinapterus leucas.

General cytological and ultrastructural features of cells found in the peripheral blood of three captive beluga whales (Delphinapterus leucas) are described. We noted all major peripheral cell types common to the circulation of mammalian species, including polymorphonuclear neutrophils, eosinophils, basophils, lymphocytes, and monocytes, as well as myelocytes, erythroblasts, and plasma cells. Platelets and two populations (normal and hypochromic) of red blood corpuscles were observed.

Animals↗
PubMed1991

Determination of prostate volume with transrectal US for cancer screening. Part I. Comparison with prostate-specific antigen assays.

To investigate whether radiologists can objectively define a high-risk group for prostate cancer, the researchers measured gland volume and compared it with results of a screening blood test, prostate-specific antigen (PSA) assay. A total of 768 men, aged 55-71 years, were self-referred to two prostate cancer screening programs using transrectal ultrasound (US) and digital rectal examination. In patients with no evidence of cancer, statistically significant increases in mean PSA values were noted with increasing gland volume ranges (P less than .05). PSA values in patients with cancer were more likely to exceed the volume-adjusted 95th percentile (mean + [1.65.standard deviation]) than those in patients with negative biopsy results (P less than .005). Patients with PSA values above the volume-adjusted 95th percentile have an estimated risk for prostate cancer up to nine times that of the general screening population. The researchers conclude that knowledge of transrectal US gland volume and prostate-specific antigen assay type are important objective variables for future prostate cancer screening programs. The volume-adjusted 95th percentiles presented may help guide cost-effective management of current early detection efforts.

Aged↗
PubMed1991

Determination of prostate volume with transrectal US for cancer screening. Part II. Accuracy of in vitro and in vivo techniques.

Improved diagnostic information is obtained when prostate volume is correlated with results of prostate-specific antigen assays for early detection of prostate cancer. Three commonly used prostate volume measurement techniques were analyzed: planimetry, prolate ellipse volume calculation (HWL), and an ellipsoid volume measurement technique. For in vitro volume measurement, the declining order of accuracy was planimetry, HWL, and ellipsoid techniques. At the 95% confidence level, inverse prediction produced full-range values for a 40-cm3 model of 5.7, 16.0, 28.8, and 32.8 cm3 for planimetry, HWL, and the two ellipsoid techniques, respectively. Despite its superior accuracy, planimetry is not available on most ultrasound units, increases estimated clinical scanning time, requires additional equipment, and is difficult for a sole operator to perform. Although less accurate than planimetry, HWL is a rapid volume measurement technique that appears to be more accurate than ellipsoid software packages; its universal availability makes it practical for routine clinical use.

Humans↗
PubMed1990

Infantile hypertrophic pyloric stenosis: experience in a district general hospital.

One hundred and twenty-nine infants with infantile hypertrophic pyloric stenosis were referred to one consultant surgeon over a 13-year period. In all cases general anaesthesia was used and a standardized surgical technique followed. No mortality was recorded. Twenty-seven infants had postoperative complications, excluding vomiting. Wound infections developed in 3% of cases and required treatment; there was no abdominal wound dehiscence. Prophylactic antibiotic treatment was not indicated. Postoperative vomiting occurred in 69% of the infants; in 15% this was severe and required an alteration in clinical management and a lengthened hospital stay. Attention to the severity rather than the incidence of postoperative vomiting will reduce morbidity further. Low morbidity and zero mortality can be achieved in non-specialist centres.

England↗
PubMed1989

Anaerobic growth defects resulting from gene fusions affecting succinyl-CoA synthetase in Escherichia coli K12.

Insertion of the fusion-generating phage Mud1 (Ap, lacZ) yielded two similar isolates, DC511 and DC512, which were unable to grow aerobically on acetate or alpha-ketoglutarate but which could use succinate, malate, fumarate, glycerol, and various sugars. These mutants were unable to grow anaerobically on most sugars unless provided with methionine, lysine, and delta-aminolevulinic acid, all of which require succinyl-CoA for their synthesis. The insertions of both mutants mapped at 17 min, in the suc operon. Enzyme assays indicated a lack of succinyl-CoA synthetase; however, full activity of the alpha-ketoglutarate dehydrogenase was retained. Beta-galactosidase expression by strains containing these gene fusions was reduced under anaerobic conditions. In aerobically grown cultures, both fusions were induced about fivefold in the presence of acetate. This type of regulation would be expected of a Krebs cycle enzyme.

Anaerobiosis↗
PubMed1989

The use of myocutaneous flaps by general surgeons.

This is a study of the use of myocutaneous flaps by general surgeons in a district general hospital over a 5 year period, and shows that such work can be satisfactorily performed by general surgeons.

Adult↗
PubMed1988

Mutants of Escherichia coli defective in acid fermentation.

Wild type E. coli ferments glucose to a mixture of ethanol and acetic, lactic, formic, and succinic acids. Mutants defective in acid production have now been isolated, including those defective in lactate dehydrogenase (LDH) or with excess alcohol dehydrogenase. These mutations had no phenotype without a pfl mutation. Novel mutants affecting acetate metabolism were isolated by insertion of the fusion vector Mudl. These aceG mutants cannot grow anaerobically on glucose or aerobically on acetate yet lack the pleiotropic growth defects of previously known pta/ack mutants. In some genetic backgrounds acetate negative mutations suppress the growth defects of adh mutations. These results are discussed in terms of redox balance.

Acetates↗
PubMed1987

Functional bracing of fractures of the second through fifth metacarpals.

A simple new brace aids in the reduction and immobilization of fractures of the second, third, fourth, and fifth metacarpals. This brace incorporates an adjustable strap and pads made of radiolucent materials. It provides 3-point fixation while allowing full range of motion of the wrist and digits. It has been preferred by patients to an ulnar gutter splint, and its use resulted in less residual angulation of the fracture than occurred with other methods.

Braces↗
PubMed1987

Patterns of urinary excretion of gold in patients with rheumatoid arthritis undergoing chrysotherapy.

Thirty patients receiving gold therapy for rheumatoid arthritis (RA) were studied for the urinary excretion of gold. Statistical analysis of all the urine specimens passed over a period of four days by each patient showed that a definite rhythm of gold excretion exists for each patient which is possibly related to water excretion but not to creatinine excretion. The study indicates possible reasons for the inability of earlier workers to relate gold excretion to the general body gold status of patients and suggests that as the study of 24 hour excretions of gold may be an insensitive marker of gold excretion, closer examination of individual patient rhythms of gold excretion could possibly provide a more useful method of analysis.

Adolescent↗
PubMed1987

Patterns of gold levels in urine, serum, and saliva in patients with rheumatoid arthritis undergoing chrysotherapy.

Twenty patients undergoing treatment with aurothiomalate for rheumatoid arthritis (RA) were studied for the presence of gold in all urine specimens passed over four days and for gold in the serum of blood drawn by venous section at 10.00, 16.00, and 22.00 hours on a single day of the study. Specimens of saliva collected at the same times as the blood specimens were also analysed for (total) gold content. Eighteen patients showed rhythmic urinary gold excretion. Variations were observed in the serum levels for total, free, and protein bound gold at different times of the day and night together with similar variations in the salivary total gold levels. It was established that a possible relation exists between urinary gold, serum gold, and salivary gold such that at times of higher urinary gold excretion the serum gold levels (total, free, and protein bound) and the total salivary gold levels were decreased. Conversely, at times of lower urinary gold excretion serum and salivary gold levels were increased.

Arthritis, Rheumatoid↗
PubMed1987

Treatment assessment of learning disabled children: is there a role for frequently repeated neuropsychological testing?

Test/retest practice effects among learning disabled (LD) and non-learning disabled (NLD) children were examined using the Halstead Category Test. Two experimental paradigms were performed. The first compared subjects on successive trials. The second paradigm used a control group to compare second trial performance of the experimental group with first trial performance of the controls. Both paradigms provide evidence of the relative inability of LD children to profit from practice. It is suggested that neuropsychological data can be used for short term test/retest as one indication of the efficacy of treatment intervention for learning disabled children without the practice effect being a significantly confounding variable.

Journal Article↗
PubMed1987

The incidence and implications of chest radiographic abnormalities following orthotopic liver transplantation.

A study of 23 patients undergoing orthotopic liver transplantation revealed that 80% of patients developed a clinically significant chest radiographic abnormality. Localized chest radiographic abnormalities generally occurred within the initial postoperative weeks and appeared to be related to the surgical procedure. Diffusely abnormal chest radiographs were most often associated with an infectious pneumonitis and rarely occurred prior to the third postoperative week. Two patients developed unusual pulmonary calcifications demonstrable by computed tomography and radionuclide bone scan.

Calcinosis↗
PubMed1987

Dendriform pulmonary ossification.

Dendriform pulmonary ossification is a rare entity associated with chronic lung disease that is almost invariably discovered as an incidental finding at autopsy. Antemortem chest roentgenograms of patients with dendriform pulmonary ossification are often interpreted as pulmonary fibrosis and/or bronchiectasis. Radiographic and pathologic findings in two cases are described herein.

Aged↗
PubMed1987

A comparison of ornithine aminotransferase from human and rat sources.

Ornithine aminotransferase was purified from human liver, rat liver and rat kidney. Sodium dodecyl sulphate polyacrylamide gel electrophoresis indicated a subunit molecular weight of 45,000 in all three cases. Estimations of the native molecular weights of ornithine aminotransferase were determined by Sephadex G-200 chromatography in the presence and absence of 0.1% (w/v) Triton X-100. Human and rat enzymes were tetrameric in the presence of detergent but the rat subunits aggregated further in its absence. Characterisation of ornithine aminotransferase from the two rat sources indicated that they were the same protein. The human and rat enzymes were similar but not identical.

Animals↗
PubMed1987

Analysis of the current-density distribution from a tapered, gelled-pad external cardiac pacing electrode.

We have designed a high-impedance (5000 omega-cm), tapered, gelled-pad, external cardiac pacing electrode that limits the migration of charges to the perimeter of a circular electrode and produces a more uniform current-density distribution than external cardiac pacing electrodes in clinical use. A computer simulation was developed that uses cylindrical coordinates to analyze the current-density distribution at the interface between the electrode and human tissue. Our computer simulation analyzed 32 different electrodes, and the results showed that the gelled-pad thickness, the gelled-pad taper, and the radius of the conducting disk were not significant parameters in determining the current-density distributions for low-resistivity electrodes. Those parameters were, however, significant for high-resistivity electrodes. We defined the optimum resistivity as that at which the tapered, gelled-pad electrode produces the most uniform current-density distribution and delivers the most current to human tissue. When evaluating electrodes at the optimum resistivity, we determined that the peak current density of the tapered, gelled-pad electrode was 50% lower than that of the clinically available electrodes, while delivering 58% more current to the human tissue.

Computer Simulation↗
PubMed1985

Use of the Limberg flap to close breast wounds after partial mastectomy.

Early experience using a rhomboid flap to reconstruct the breast after partial mastectomy and axillary clearance of glands is encouraging. This operation has been used in 7 cases to reconstruct breasts after partial mastectomy and axillary clearance of glands and has given a good cosmetic result.

Adult↗