PubMed Health⌕ Search

Biomedical subjects

R Davidson

Publications and source records attributed to R Davidson.

At least 73 records · Page 4Linked to original sources
PubMed1984

(A gamma delta beta) thalassaemia: similarity of phenotype in four different molecular defects, including one newly described.

Globin gene mapping of DNA from families with (A gamma delta beta) thalassaemia has revealed a previously unreported gene deletion responsible for this condition. The deletion removes the A gamma, delta and beta genes and while its 5' end is in a similar position to that described in a previous deletion of this type, the 3' ends of the two deletions are quite different. In addition we have observed further examples of two other previously described deletions which result in this disorder. Phenotypic comparisons of families with (A gamma delta beta) thalassaemia, in which the molecular basis has been defined, show a remarkable similarity among the four different deletion defects, with important implications with regard to the mechanism by which deletions allow the continued expression of gamma genes.

Adolescent↗
PubMed1984

Neurosyphilis presenting as a focal mass lesion: a case report.

A patient with subacute aphasia and hemiparesis was found to have a low density white matter lesion with mass effect on the computed tomographic (CT) scan. Serological examination and biopsy established the diagnosis of paretic neurosyphilis. This CT appearance has not previously been described in cases of neurosyphilis. Neurosyphilis should be considered as a potentially treatable cause of a cerebral mass lesion.

Biopsy↗
PubMed1983

Glioblastoma of the cerebellum. Computed tomographic and pathologic considerations.

Cerebellar glioblastoma is a brain malignancy that is often difficult to distinguish from metastatic disease in the elderly before biopsy. The clinical course and computed tomographic appearance of four patients with multiform glioblastoma of the cerebellum are presented and correlated with other reports in the literature. The appearance of a cerebellar hemispheric lesion with little mass effect is described, and the pathology of the tumor is reviewed.

Aged↗
PubMed1983

Cast brace management of the femoral shaft fracture in children and young adults.

Seventy-two children and adolescents, 5-19 years of age, sustaining femoral fractures were treated with immediate cast bracing at Oklahoma Children's Memorial Hospital. Ambulation was started an average of 3 days after fracture when there were no associated injuries. The average length of hospitalization was 18.7 days; the average length of immobilization in plaster was 67.4 days. Results were generally comparable to those of more standard methods of treating a fractured femur in this age group. Proximal as well as middle and distal fractures were treated, but varus and anterior angulation was not well controlled in proximal fractures. No patient had a clinically significant deformity. Sixty-one percent of the entire group healed with less than 6 mm discrepancy. Middle-third fractures showed more tendency toward shortening. All six fractures that healed with more than 1.5 cm of shortening were middle third. No injured femur was longer than the uninjured femur at a 6-month follow-up. Immediate cast bracing can provide an opportunity for early ambulation and avoid the sequelae of immobilization. Weekly assessment for the first 4 weeks is mandatory to monitor length and angulation. The adolescent male with a midshaft fracture was most difficult to manage, and in this situation, closed intramedullary nailing is recommended.

Adolescent↗
PubMed1980

The need for power, brain norepinephrine turnover and learning.

This experiment was designed to explore whether brain norepinephrine (NE) serves as a specific reward system for the power drive. Previous research has indicated that 3-methoxy-4-hydroxyphenyl glycol (MHPG), a urinary metabolite reflecting central NE turnover, is positively correlated with features of assertiveness which one might expect of a person high in the need for power (n power) or in a state of aroused power motivation. Twenty-seven male undergraduates, 13 of whom were high and 14 of whom were low in n power as assessed by a TAT measure, were recruited as subjects. Before and after the laboratory session, subjects voided all urine and concentrations of epinephrine, norepinephrine and MHPG were obtained from samples. The laboratory task consisted of 20 picture-word pairs in which the subject had to learn to anticipate the word associated with each picture before the word was presented. Five pairs of stimuli in each of the following picture-word combinations were presented 12 times: neutral-neutral, neutral-power, power-neutral and power-power. The results revealed that, as predicted, subjects high in n power learn most power-related material faster than subjects low in n power. The need for achievement is unrelated to the learning of any picture-word pairs. The neurochemical data indicated that subjects maintaining a relatively high MHPG excretion rate during the experiment who were also high in n power showed the greatest mastery of power related compared with neutral picture-word pairs. These findings are consistent with the hypothesis that brain NE turnover is specifically related to the learning of power-related responses in subjects high in n power.

Assertiveness↗
PubMed1980

Autosensitization and immune complexes in chronic idiopathic thrombocytopenic purpura.

Argument exists as to whether platelet damage in chronic idiopathic thrombocytopenic purpura (ITP) is mediated by an autoimmune response to platelet antigen or by immune complexes. We have studied thirty-nine patients with ITP for evidence of (i) sensitization to platelet antigen, using a macrophage migration inhibition factor (MIF) assay, (ii) circulating immune complexes, using a Clq deviation technique, and (iii) serum-induced platelet 'immunoinjury', using a 3H-serotonin release assay. Eighty-one per cent of the patient group had a migration index of less than 0.8 (normal range 0.8-1.3), while 91% of those tested had a serum factor (presumably immune complexes) which bound to labelled Clq. The serotonin release assay was abnormal in 32% of twenty-two patients, and the results of this test bore no clear relationship to either those of the Clq deviation test or the MIF results. We conclude that most patients with ITP are sensitized to platelet-associated antigen, and have circulating immune complexes. The contribution of these factors to platelet destruction and the nature of the antigen in the complexes remain to be demonstrated. The serotonin release assay is less sensitive, non-specific, and has limited value in the diagnosis of ITP.

Antigen-Antibody Complex↗
PubMed1980

Meningitis, ventriculitis, and hydrocephalus: a complication of fetal monitoring.

A case is presented of meningitis, ventriculitis, and hydrocephalus secondary to the use of fetal scalp monitoring. The most commonly reported fetal complication related to the application of the scalp electrode is the development of a scalp abscess; the incidence varies between 0.45 and 4.5%, but several other complications have also been reported and the overall incidence is not well established. Infants in whom a scalp electrode has been used should be carefully examined to detect potential serious complications.

Adolescent↗
PubMed1978

Casualty room presentations and schoolboy rugby union.

For eight years a casualty station has been operating during competition Rugby Union matches at a large Sydney School. During this time, both diagnosis and treatment have been recorded for every presentation. The casualty station was attended by 556 boys over this period, and approximately 50% of these presentations were for trivial injuries. Forty-three severe injuries occurred, of which most were fractures. The rate of presentation, and the pattern of injury, changed as a greater number of both minor and major injuries than did visitors. There was one injury in boys less than 12 years old, and the greatest incidence of injury was in boys aged from 16 to 18 years. It is concluded that there is a place for casualty services at schoolboy competition games, and that the supervised Rugby Union played in this and comparative school competitions is a reasonably safe game for boys less than 16 years old, to whom issues of schoolboy participation are most applicable.

Adolescent↗
PubMed1978

Defect in biosynthesis of the linkage unit between peptidoglycan and teichoic acid in a bacteriophage-resistant mutant of Staphylococcus aureus.

The biosynthesis of the linkage region between peptidoglycan and the ribitol teichoic acid was investigated in the bacteriophage-resistant, teichoic acid-less mutant Staphylococcus aureus 52A5 (Chatterjee et al., J. Bacteriol. 100:846--853, 1969). Membrane preparations of this strain were found to be incapable of forming the first intermediate of the biosynthetic pathway, namely, the transfer of N-acetyl-D-glucosamine (GlcNAc) from UDP-GlcNAc to the acceptor molecule, which presumbably is undecaprenol phosphate (R. Bracha and L. Glaser, Biochem. Biophys. Res. Commun. 72:1091--1098, 1976). The addition of heat-inactivated membrane preparations of S. aureus 52A2 (which normally has ribitol teichoic acid) that had been preincubated with UDP-GlcNAc to membranes of strain 52A5 enabled the synthesis of teichoic acid. These data suggest that the mutational defect in the teichoic acid-less organism is in the synthesis of the first compound of the linkage unit, and this is apparently the reason for its absence in the cell walls.

Cell Wall↗