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Biomedical subjects

D Law

Publications and source records attributed to D Law.

At least 55 records · Page 3Linked to original sources
PubMed1991

Problems of thermonuclease detection for identifying Staphylococcus aureus in blood culture broths.

The detection of thermonuclease by the Oxford strain and eight clinical isolates of Staphylococcus aureus in a variety of bacteriological broths with and without added blood was examined using a toluidine blue-DNA-agar plate method. In Isosensitest, brain-heart infusion, tryptic soy, nutrient and gas-liquid chromatography broths (all of which do not contain liquoid) thermonuclease detection was uncomplicated. In Bactec broths (containing liquoid) detectable thermonuclease activity was greatly reduced in the absence of blood. The addition of 10% blood to the Bactec broths restored the activity. Liquoid was shown to be responsible for the inhibition of thermonuclease activity, and its effect could be neutralised by the addition of blood, albumin, or haemoglobin. In specimens containing no blood, or insufficient blood to neutralise the liquoid in culture broths, more has to be added to prevent false negative reporting of S aureus. This can be done after growth at the time of thermonuclease testing. Clinical consequences of delayed identification of S aureus in routine blood cultures may be serious. The application of the thermonuclease test to blood culture broths is both fast and specific.

Culture Media↗
PubMed1990

Comparison of the NES and CNS/B neuropsychological screening batteries.

Computer and hand administered neuropsychological tests are utilized in the evaluation of central nervous system changes associated with environmental or occupational exposure to neurotoxicants. This study compares the computerized Neurobehavioral Evaluation System (NES) developed by Baker et al., 1985, with the hand administered California Neuropsychological Screening Battery (CNS/B) developed by Bowler et al., 1986. Both batteries were designed for screening of the effects of neurotoxicants on the central nervous system and require less than one hr to administer. Both screening batteries consist of tests of: mood, word knowledge, attention, concentration, learning and memory and psychomotor and visuomotor and visuospatial abilities. They were administered in a standardized fashion to 106 subjects. Results indicate strong positive correlations for tests of word knowledge, moderate correlations for attention and concentration, while weaker correlations were obtained for tests of memory, psychomotor and visuomotor and visuospatial ability. The NES may be more useful for large epidemiological studies while the CNS/B appears more useful for individual screening and clinical studies.

Anxiety Disorders↗
PubMed1989

Cross-sectional neurotoxicology study of lead-exposed cohort.

Although the toxic effects of lead have been known for centuries, lead intoxication is still widespread in the United States. Without baseline tests of neuropsychological, neurobehavioral and neurophysiological testing it may be difficult to detect subtle changes in neurological function after lead exposure. This may be further confounded by partial chelation treatment and exposure to neurotoxic mixtures or inability to quantitate alcohol consumption. We undertook a cross-sectional study to address these problems in 24 exposed and 29 control subjects in a plant that manufactured electrical components using fritted leaded glass to coat capacitors and transistors. Potentially exposed workers had blood lead levels ranging between 3 micrograms/dL to 135 micrograms/dL. Industrial hygiene monitoring revealed the plant's air lead levels ranged from 61 micrograms/m3 to 1,700 micrograms/m3 in excess of OSHA permissible exposure limits of 40 micrograms/m3/10 hr day. Using a specially designed battery of neurophysiological, neurobehavioral and neuropsychological screening tests, we demonstrated a significant difference from controls in measures of psychomotor speed, motor strength and verbal memory. Although limited by the cross-sectional design, these findings support the hypothesis that the battery of neurophysiological, neuropsychological and neurobehavioral tests can detect a significant inter-group differences between lead-exposed and control subjects.

Adult↗
PubMed1989

Functional electrical stimulation for upper limb strengthening in traumatic quadriplegia.

The hypothesis of this study was that the functional electrical stimulation (FES)-assisted exercise of partially paralyzed arm muscles would result in significantly greater muscle strength in the arms of spinal cord injured quadriplegics than equal periods of conventional isotonic exercise. Single muscles were studied in seven subjects in a crossover design consisting of equal periods of FES-assisted exercise and conventional exercise. It was concluded that for these subjects using this exercise regime, neither FES-assisted exercise nor conventional exercise produced improvements in maximum voluntary force that were either statistically or functionally significant. The results, although disappointing, have helped these subjects to be more realistic about the potential therapeutic benefits of FES.

Adult↗
PubMed1988

Aspiration cytology in the management of breast lesions.

In a group of patients with breast lumps, diagnosis made by pre-operative aspiration cytology was compared with that obtained by histological section of excised specimens. Results showed that aspiration cytology correctly diagnosed 89% of malignant lesions and 92.6% of benign lesions based upon histological diagnosis. Cytological diagnosis of benign disease had a false negative rate of 6% while cytological diagnosis of malignant disease had a 2.7% false positive rate. Only 3.5% of cytologies returned an inadequate diagnosis. This study shows that aspiration cytology should be useful in allowing a better psychological preparation of patients before surgery as well as better utilization of operation theatre facilities.

Biopsy, Needle↗
PubMed1987

Examination of enteropathogenic Escherichia coli strains for an adenylcyclase stimulating factor.

Enteropathogenic Escherichia coli strains are a common cause of infantile diarrhoea but do not produce recognised enterotoxins. Three strains of proven virulence were examined for toxins which may be missed in conventional tests. Cell lysates and concentrated culture supernates of organisms grown in five different media gave negative results when examined for adenylcyclase stimulating activity. The additions of zinc ions or lincomycin to these media or the use of iron-depleted media also gave negative results. The significance of these findings and the possible role of other toxins in diarrhoea due to enteropathogenic E. coli are discussed.

Adenylyl Cyclases↗
PubMed1983

Brain amino acids measured by intracerebral dialysis in portacaval shunted rats.

Changes in brain amino acid uptake and metabolism have been proposed as a possible etiological factor in hepatic encephalopathy. By use of a brain dialysis technique (a thin tube implanted in the brain of the living animal), the extracellular amino acid concentrations in the striatum of portacaval (PC)-shunted and sham-operated rats were measured. Leucine, phenylalanine, methionine, and glutamine were increased two- to sixfold in the PC-shunted rats, whilst no changes were seen for GABA, valine, glutamate, or isoleucine, confirming previous reports. Aspartate levels were 350% higher in the PC-shunted rats, and this rise, as well as that of phenylalanine, was significantly correlated with the lower motor activity observed in the PC-shunted rats, suggesting a possible importance of these amino acids in the etiology of hepatic encephalopathy. The amino acid concentrations measured in whole blood demonstrated the well-known pattern of low levels of branched-chain amino acids and increased concentrations of phenylalanine, glutamine, and histidine.

Amino Acids↗