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Biomedical subjects

R E Davis

Publications and source records attributed to R E Davis.

At least 235 records · Page 13Linked to original sources
PubMed1981

The association of bacteriuria and reduced serum pyridoxal concentrations in patients with diabetes mellitus.

Of 1017 patients admitted to the Royal Perth Hospital Diabetic Survey 142 were found to have significant bacteriuria. In these bacteriuric patients serum pyridoxal concentrations were significantly reduced (P = less than 0.001) when compared with 142 diabetic patients matched for age (+/- 5 years) and sex but without infection of the urinary tract. Measurements were repeated up to 6 mth after antibacterial treatment and serum pyridoxal concentrations were still low. Pyridoxal has a role in immunological competence, and it is possible that the increased incidence of urinary tract infection in patients with diabetes reflects impaired immunological competence due to pyridoxal deficiency.

Bacteria↗
PubMed1981

Behavioral investigation of neurotoxicity: the effects of colchicine, lumicolchicine and vincristine sulfate on goldfish optic nerve regeneration.

Experiments were carried out to investigate a behavioral method of assessing neurotoxicity. The proposition is that developing or regenerating neurons. The regenerating optic nerve in goldfish was examined as a preparation for investigating the effects of chemicals on neuronal development. Restoration of optic nerve connections following crushing of the optic nerve, as detected by a noninvasive behavioral technique permitting sequential testing of individual fish, occurred within 17 days. The effect on regeneration of biweekly, intraperitoneal administration of alkaloid neurotoxins was investigated. Regeneration was inhibited by colchicine and vincristine sulfate but not by lumicolchicine. The potency of vincristine was approximately twice that of colchicine. Neither drug had a detectable effect on the maintenance of optic nerve function in sham-operated fish. The results suggest that the behavioral protocol can be used to identify chemical agents which impair neuronal development in vivo, and to estimate their relative neurotoxicity.

Animals↗
PubMed1980

Association of retinopathy and glycosylated haemoglobin levels in diabetes mellitus.

One hundred and forty patients with diabetes mellitus were examined in the small mining town of Kalgoorlie, Western Australia. The primary object was to determine the incidence of retinopathy in the diabetic community. One hundred and thirty-eight sets of data were obtained. There were 69 males and 69 females. The diabetes was controlled with orally administered hypoglycaemic agents in 62 patients, in 58 patients with insulin, and in 18 by diet alone. Forty-six of the 138 volunteers (33%), were found to have retinopathy and this included eight of the 14 Aboriginals taking part in the survey. Glycosylated haemoglobin levels ranged from 8.1% to 18.8% (mean 11.7%; SD; 2.28%) of total haemoglobin concentration, and plasma glucose levels from 1.2 mmol/L to 27.3 mmol/L (mean, 9.5 mmol/L, SD, 5.06 mmol/L); there was a positive correlation between levels of glycosylated haemoglobin and plasma glucose (r = 0.63; P less than 0.001). Diabetics with retinopathy had a mean glycosylated haemoglobin level of 12.5% compared with 11.3% in those without this complication. Examination by treatment groups showed that patients with retinopathy whose disease was controlled with insulin had significantly higher levels of glycosylated haemoglobin compared with those without this complication (0.01 greater than P greater than 0.001). Patients whose disease was controlled with orally administered hypoglycaemic agents did not show this difference.

Adolescent↗
PubMed1980

DNA homology among diverse spiroplasma strains representing several serological groups.

Deoxyribonucleic acid (DNA) homology among 10 strains of spiroplasma associated with plants and insects was assessed by analysis of DNA-DNA hybrids with single strand specific S1 nuclease. Based on DNA homology, the spiroplasmas could be divided into three genetically distinct groups (designated I, II, and III), corresponding to three separate serogroups described previously. DNA sequence homology between the three groups was less than or equal to 5%. Based on DNA homology, group I could be divided into three subgroups (A, B, and C) that corresponded to three serological subgroups of serogroup I. Subgroup A contained Spiroplasma citri strains Maroc R8A2 and C 189; subgroup B contained strains AS 576 from honey bee and G 1 from flowers; subgroup C contained corn stunt spiroplasma strains I-747 and PU 8-17. There was 27-54% DNA sequence homology among these three subgroups. Group II contained strains 23-6 and 27-31 isolated from flowers of tulip tree (Liriodendron tulipifera L.). Group III contained strains SR 3 and SR 9, other isolates from flowers of tulip tree. Based on thermal denaturation, guanine plus cytosine contents of DNA from five type strains representing all groups and subgroups were estimated to be close to 26 mol% for group I strains, close to 25 mol% for group II strains, and close to 29 mol% for group III strains. The genome molecular weights of these five type strains were all estimated to bae about 10(9).

DNA, Bacterial↗
PubMed1979

Transection of direct anterior thalamic afferents from the hippocampus: effects on activity and active avoidance in rats.

This investigation demonstrates the importance of the direct hippocampo-anterior thalamic component of the postcommissural fornix in the control of general locomotion and active avoidance. Transection of anterior thalamic afferents from the hippocampal formation (subicular cortex), at the point where they exit from the fornix posterior to the septum, is sufficient to enhance bidirectional active avoidance acquisition and increase general activity. This transection may also interrupt fibers to or from other thalamic nuclei and the anterior septum. However, destruction of connections of the anterior septum with the hippocampus, habenula, and thalamus by transection in the coronal plane anterior to the descending fornix columns, without damage to the subiculothalamic fibers, increases general activity levels without damage to the subiculothalamic fibers, increases general activity levels without affecting active avoidance behavior. The activity increase in this case resembles that seen after septal lesions rather than that seen after hippocampal lesions. Thus, destruction of a single fornix component contributing afferents to the anterior thalamic nuclei reproduces at least part of the hippocampal syndrome. This suggests that these fibers contribute significantly to the control of these behaviors and may mediate active avoidance changes resulting from hippocampal and fornix damage.

Afferent Pathways↗
PubMed1979

Use of low ionic strength saline for crossmatching and antibody screening.

A totally revised crossmatching and antibody screening procedure has been designed using low ionic strength saline as the suspending medium for red cells in the saline and enzyme phases as well as the antiglobulin test. The replacement of Pasteur pipettes with precision samplers for all serum and red cell dispensing has resulted in improvement in the reproducibility and standardisation of technique. The major advantages are improved sensitivity, shortened incubation time, and simplicity of technical performance.

Blood Grouping and Crossmatching↗
PubMed1979

Spiroplasmas: serological grouping of strains associated with plants and insects.

Spiroplasma strains from plant and arthropod hosts, and from surfaces of flowers, were classified into three serological groups (designated I, II, and III) based on results from growth-inhibition tests. No significant cross reactions were observed among groups. The groupings were confirmed by ring-interface precipitin and microprecipitin tests, using membrane preparations as test antigens, and by organism-deformation tests. Serogroup I contained three subgroups: subgroup A (Spiroplasma citri strains Maroc R8A2 and C189), subgroup B (strain AS 576 and closely related strains from honeybee or flowers), and subgroup C (corn stunt spiroplasma strains). Serogroup II contained strains 23-6 and 27-31 isolated from flowers of the tulip tree (Liriodendron tulipifera L.) growing in Maryland. Serogroup III contained strains SR 3 and SR 9 isolated from flowers of the tulip growing in Connecticut. The subgroups of serogroup I were based on organism deformation, microprecipitin, and ring-interface precipitin tests. The data are consistent with the hypothesis that the three serogroups represent no less than three distinct spiroplasma species.

Animals↗
PubMed1979

Manic-depressive variant syndrome of childhood: a preliminary report.

The author describes the specific diagnostic entity of manic-depressive variant syndrome of childhood and outlines the five essential diagnostic criteria (affective storms, family history of significant affective dysfunction, hyperactivity, chronically disturbed personal relationships, and absence of psychotic thought disorder) and the five secondary criteria (sleep disturbances, minimal brain dysfunction, abnormal EEG, enuresis, and neuropathology). In the four cases reported, the children, when properly diagnosed, responded well to lithium therapy. The author points out the need for further study of this syndrome. Precautions about the use of lithium in children under age 12 are crucial, as is the need for continuing psychotherapy for parents and child.

Adolescent↗
PubMed1979

A rapid method for the quantitation of haemoglobin A2.

A rapid accurate and inexpensive technique for the measurement of haemoglobin A2 has been devised. It uses a small plastic device which embodies a miniature chromatographic column and reservoirs for the eluting buffer and eluates. The device is charged with whole blood, pH 8.25 buffer and centrifuged. The eluate is removed and the centrifugation repeated using pH 7.0 buffer to remove the remaining haemoglobin. The haemoglobin concentration in the 2 volumes of eluates is measured in a spectrophotometer at 414 nm and the percentage of HbA2 calculated. Results are similar to those obtained by standard methods.

Adolescent↗
PubMed1979

Macrocytic anaemia.

Macrocytosis of red cells is now more easily and precisely detected in the laboratory by the adoption of electronic methods of cell volume measurement. This means the practitioner will be more frequently faced with the problem of what an elevated mean corpuscular volume (MCV) means. Macrocytic anaemia is not synonymous with folate or cobalamin deficiency, there being many causes of non-megaloblastic macrocytosis including excess alcohol, hypothyroidism, and liver disease. The commonest cause is blood regeneration as after a bleed, or in response to a haematinic or in haemolysis, as reticulocytes are large red cells and will raise the MCV. Megaloblastic anaemia, as in folate or cobalamin deficiency, has a normal or low reticulocyte count and a multiplicity of causes which must be identified as the cause may require treatment in its own right as well as the prescription of the required vitamin.

Anemia, Macrocytic↗
PubMed1978

Illegal drugs and nutrition in undergraduate students.

The nutritional status of 82 marihuana-smoking students from two establishments of tertiary education was studied and compared with 63 controls. There was little difference between these two groups of students. Thirty-four per cent of those taking drugs had a diet which was deficient in one or more nutrients, compared with 30% of the controls. Four of the students who took drugs and three controls had a marginally reduced serum level of vitamin B12, but all were taking oral contraceptive agents. Sixteen marihuana-smokers had either a low folate or low pyridoxal serum level, and another three had reduced serum levels of both vitamins compared with a total of eleven among the controls. Forty-three students (52%) had used, or were using, lysergic acid diethylamide (LSD) in addition to marihuana, and 10 had used mushrooms (Psilocybe cubensis). Thirteen students appeared to be "stoned" at interview.

Adolescent↗
PubMed1978

Glycosylated haemoglobin levels in patients with diabetes mellitus.

Glycosylated haemoglobin A1 levels were measured in 186 patients with diabetes mellitus and 108 non-diabetic controls. Forty-nine diabetics were considered well controlled with at least three blood glucose levels below 10 mmol/L, while 50 diabetic patients were poorly controlled with at least three blood glucose levels above 15 mmol/L. Mean glycosylated haemoglobin A1 levels for the 108 normal controls was 7.45% +/- 0.73%, for the well controlled diabetics, 10.7% +/- 2%, and for poorly controlled diabetics, 15.0% +/- 2.5% of total haemoglobin. In patients with the onset of diabetes after the age of 40 years, there was a significant difference between the haemoglobin A1 levels in those with diabetic retinopathy and those without complications. There was a significant association between haemoglobin A1 levels and the duration of the disease in diabetics controlled with insulin.

Adult↗
PubMed1978

Acute upper-gastrointestinal hemorrhage. New observations on an old problem.

In a two-year period, 289 patients with acute upper-gastrointestinal hemorrhage were evaluated. The site of hemorrhage was proven by endoscopy in more than 90% of cases. The frequency of any particular bleeding site was characterized for several subgroups and was found to correlate with: (1) the severity of the bleeding episode; (2) the iatrotropic stimulus of hemorrhage, and (3) the history of ethanol consumption. No difference was found in the frequency of ulcer and acute mucosal lesions as sites of hemorrhage between patients who consumed aspirin and those who did not. A history of symptoms of peptic ulcer correlated with the presence of an ulcer as the bleeding site. It is possible that failure to identify important patient subgroups may be partially responsible for the disagreement between previous reports.

Alcohol Drinking↗