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Biomedical subjects

K Murray

Publications and source records attributed to K Murray.

At least 145 records · Page 8Linked to original sources

Urinary retention after total hip replacement. A prospective study.

We report a prospective study of the factors associated with acute urinary retention after total hip replacement in 103 consecutive male patients. Eleven patients (10.7%) developed retention after operation. Of the factors investigated before operation three had predictive value: inability to pass urine into a bottle whilst lying in bed, urinary peak-flow rates indicative of obstruction, and a history of previous bladder outflow problems. This study suggests that patients showing one or more of these factors should be assessed and if necessary treated by a urologist before arthroplasty, so as to avoid the need for catheterisation, and the consequent risk of deep infection.

Adult↗

A protein specific to mitochondria from S-type male-sterile cytoplasm of maize is encoded by an episomal DNA.

Mitochondria of S-type cytoplasmic male sterile maize contain two linear double-stranded DNA molecules, S1 and S2. Two open reading frames (ORF1 and ORF2) are present in S2 DNA. Fragments from ORF1 were inserted into plasmids to achieve expression in Escherichia coli. Cells transformed with recombinant plasmids produced mRNA which hybridized with ORF1 and corresponding polypeptides were synthesized by in vivo and in vitro systems. Antiserum against a lacZ/S2 fusion protein precipitated the anticipated polypeptides from transformed E. coli cells and was therefore used to detect homologous peptide sequences in protein preparations of mitochondria from different maize cytoplasms. The antiserum detected a protein of 125 000 M(r) present in mitochondria from male sterile B73S but absent from the fertile B73N cytoplasm.

Journal Article↗

Expression of the X gene of hepatitis B virus.

The hepatitis B virus (HBV) genome carries an open reading frame of 462 bases, the X region, but the corresponding protein has yet to be identified as a natural product. In rodent cells cotransformed with the thymidine kinase gene of herpes simplex virus and HBV DNA, however, Gough [1983] identified a mRNA that hybridises uniquely with the X region of the HBV genome. A large fragment of the X region was inserted into plasmid pCL19 delta Y-T in order to produce, in Escherichia coli, the X gene product, HBxAg, as a polypeptide fused to the N-terminal part of the phage lambda cro gene product. Antisera raised against this fused polypeptide gave positive immunofluorescence reactions with the transformed rodent cells. This provides direct evidence for the expression of the HBxAg gene in eukaryotic cells transformed with HBV DNA. The approach used here should be generally applicable.

Amino Acid Sequence↗

Transvesical phenolisation of the pelvic plexuses: a simple technique for the treatment of refractory detrusor instability and hyperreflexia.

A simple endoscopic technique for the infiltration of pelvic plexuses with phenol is described. The results suggest that this is a useful technique in the management of detrusor hyperreflexia and for the older patient with detrusor instability when standard conservative measures have failed. It is contraindicated in male patients because of the risk of impotence.

Adolescent↗

Primary malignant lymphoma of the central nervous system. Results of treatment of 11 cases and review of the literature.

Eleven patients with primary malignant lymphoma of the central nervous system (CNS) were treated at the Medical College of Wisconsin Affiliated Hospitals between 1964 and 1984. Three patients had a prior history of immunosuppressive therapy following renal transplantation. All patients had biopsy-proven disease and 10 of the 11 were treated with external radiation therapy. The doses to the primary tumor ranged from 34 to 59.4 Gray (Gy). Actuarial (life-table) survival rate was 82% at 1 year and 43% at 3 years. No recurrence was seen after 13 months. Eighty-six reports totaling 693 cases of primary malignant lymphoma of the CNS were found in the literature. Of these, 308 cases were treated with a combination of surgery and irradiation. Overall survival at 5 years for those patients who received more than 50 Gy compared with less than 50 Gy to the primary tumor was 42.3% versus 12.8% (p less than 0.05). Twenty-one patients survived longer than 5 years. Late relapse was notable, with 10 (47.6%) of 21 tumors recurring between 5 and 12.5 years after diagnosis. Based on this review, a minimum of 50 Gy radiation to the primary tumor is recommended. While no statement regarding the efficacy of craniospinal irradiation or chemotherapy can be made in view of the small numbers, the use of craniospinal irradiation and/or systemic chemotherapy should be considered for future trials.

Adult↗

In vitro studies on the comparative sensitivities of cells of the central nervous system to diphtheria toxin.

We have used tissue culture techniques and cell type-specific antibodies to compare the sensitivity of the various cell types of the white matter tracts of the rat central nervous system to in vitro exposure to diphtheria toxin (DTx). We have found that oligodendrocytes and Type 2 astrocytes (Raff et al. 1983a), which at least in the rat optic nerve, appear to be derived from a single bipotential progenitor cell (Raff et al. 1983b), are both more susceptible to DTx than are either Type 1 astrocytes or spinal neurones. The loss of oligodendrocytes and Type 2 astrocytes caused by exposure to DTx in vitro appeared to be irreversible. Even when cultures were maintained for a month following initial treatment with DTx, these glial populations were not reestablished, suggesting that precursors for these macroglial cell types were as sensitive to the effects of DTx as were the oligodendrocytes and Type 2 astrocytes themselves. Our results are discussed in the light of the failure of diphtheritic lesions to remyelinate in vivo.

Animals↗

Low pressure/low flow voiding in younger men: psychological aspects.

Low pressure/low flow voiding in young and middle-aged males in the absence of outflow tract obstruction has been reported as being associated with anxiety and a high incidence of dyspepsia. To assess objectively the psychological basis of this condition, an unselected group of 50 men aged 25 to 55 years was evaluated by psychiatric interview, questionnaires and urodynamic tests. In addition, patients involved in an earlier study were psychologically evaluated. Low pressure/low flow voiding was demonstrated in three (6%) of the new patients. This voiding pattern was related to a long preceding history, stress-dependent symptoms and difficulty in voiding in public urinals. When compared with a control population, the experimental group scored significantly higher on measures of psychoneurosis. It is recommended that surgery be avoided in these patients and that simple behavioural therapy may be most appropriate.

Adult↗

Purified astrocytes promote the in vitro division of a bipotential glial progenitor cell.

Optic nerves of neonatal rats contain a bipotential glial progenitor cell which can be induced by tissue culture conditions to differentiate into either an oligodendrocyte (the myelin-forming cell of the CNS) or a type 2 astrocyte (an astrocyte population found only in the myelinated tracts of the CNS). In our previous studies most oligodendrocyte-type 2 astrocyte (O-2A) progenitor cells differentiated within 3 days in vitro with relatively little division of the progenitors or their differentiated progeny. We have now found that the O-2A progenitors are stimulated to divide in culture by purified populations of type 1 astrocytes, another glial cell-type found in the rat optic nerve. This cell-cell interaction appears to be mediated by a soluble factor(s) and results in the production of large numbers of both progenitor cells and oligodendrocytes. As type 1 astrocytes are the major glial cell-type in the optic nerve when oligodendrocytes first begin to be produced in large numbers in vivo, our results suggest that this astrocyte subpopulation may play an important role in expanding the oligodendrocyte population during normal development.

Animals↗

Results of transvesical infiltration of the pelvic plexuses with phenol in 116 patients.

One hundred and sixteen patients with detrusor instability, detrusor hyper-reflexia or bladder hypersensitivity who had failed to respond to standard conservative methods of management were treated by transvesical infiltration of the pelvic plexuses with phenol. A satisfactory response was obtained in detrusor hyper-reflexia (82%), in detrusor instability in patients over 55 years of age (69%) and in idiopathic bladder hypersensitivity (68%). The response rate was much less satisfactory in detrusor instability in patients less than 55 years of age (14%) and when there was a definable cause for bladder hypersensitivity (0%).

Adolescent↗

Acute urinary retention--a urodynamic assessment.

Thirty male patients with acute urinary retention were studied by standard urodynamic techniques on admission to hospital. Ten individuals also underwent cystography and sequential urodynamic testing over 96 h. Twenty-three per cent of patients did not require subsequent prostatectomy. Inability to initiate a voiding contraction during cystometry at the time of admission was associated with a prolonged duration of retention and a greater retained volume. The internal urethral meatus is closed in retention, and release of the retention results in an increase in profile length and maximum urethral closure pressure and a decrease in maximum urethral pressure. Free catheter drainage was associated with a reduction in bladder capacity and the appearance of detrusor instability.

Acute Disease↗

Yeast H3 and H4 histone messenger RNAs are transcribed from two non-allelic gene sets.

The genes coding for the H3 and H4 histones of Saccharomyces cerevisiae have been isolated by recombinant DNA cloning. The genes were detected in a bacteriophage lambda library of the yeast genome by hybridization with plasmids containing the cloned Psammechinus miliaris sea urchin histone genes (pCH7) and the cloned Drosophila histone genes (cDM500). Two non-allelic sets of the H3 and H4 genes have been isolated. Each set consists of one H3 gene and one H4 gene arranged as a divergently transcribed pair separated by an intergene spacer DNA. The histone genes were located on the cloned yeast fragments by S1 nuclease mapping, as was a gene (SMT1) of unknown function that does not code for a histone but is closely linked to one of the histone sets. Sequence homology between the two non-allelic sets is confined to the coding regions of the respective genes while the flanking DNA and intergene spacer DNA are extensively divergent. Cellular RNA homologous to the histone genes, including transcribed non-coding sequences unique to each of the four genes, was detected by S1 mapping, thus demonstrating that all four genes are transcribed in vegetative cells.

Base Sequence↗