The Leeuwenhoek lecture, 1985. A molecular biologist's view of viral hepatitis

Three forms of viral hepatitis can be distinguished serologically. Hepatitis A virus is a picornavirus, which is being studied increasingly after its propagation in cell cultures. The B virus (HBV) is the prototype of a family now termed hepadna viruses and is by far the best understood. The third, by exclusion, is non-A non-B, about which little else is known. Molecular cloning methods enable copies of viral genes to be propagated and analysed quite readily and provide the means for isolation and expression of individual genes in microbial and animal cells. Determination of the nucleotide sequences of HBV DNA revealed its genetic organization and so guided studies of the mechanism of gene expression both in infected animals and cultures of transformed cells. Replication of the viral genome has also been studied in natural infections, particularly with duck HBV, but also with the human virus. Expression of HBV genes in microbial cells is valuable as a source of antigens for diagnostic reagents and vaccine preparations, but has also been of consequence for the identification of viral gene products not previously recognized and which are of considerable current interest. The methods and materials now available provide additional opportunities for inquiring into the course of viral infection, replication of the virus and, for HBV, the possible role in the development of hepatomas of integration of the viral genome into the host chromosome.

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.

An epidemiological study of high school ice hockey injuries

Between 1976 and 1983, 42 spinal cord injuries among ice hockey participants were documented in Canada; within a recent 3-week period, three cases involving fractured necks were reported in a metropolitan area of Minnesota. The purpose of this comprehensive epidemiological study was to document rates, types, and severities of injuries incurred among high school varsity hockey players in Minnesota, as a result of participation in the 1982-1983 season, and to determine the variables associated with these injuries. Within a 30-mile radius of the state's major metropolitan area, 12 high school varsity hockey teams were selected for participation. Specific techniques were used to ensure confidentiality, high response rates, and validation of information. Among the players an injury rate of 75 injuries per 100 players was documented. Head and neck injuries accounted for 22% of the total injuries. Increased risks of injury were associated with multiple health-care provision variables and equipment utilized. Potential strategies are identified as a result of these findings.

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.

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.

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.

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.

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.

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.

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%).

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.

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.

Clean intermittent self-catheterisation in the management of adult lower urinary tract dysfunction

The results of clean intermittent self-catheterisation in a group of 57 patients (2 male, 55 female) followed for up to 5 years are reported. The benefits in patient management are discussed and particular note is made of this technique for female patients with chronic urinary retention and overflow incontinence.

Hepatitis B virus antigens made in microbial cells immunise against viral infection

Chimpanzees have been vaccinated successfully against hepatitis B virus with preparations of the viral antigens made in microbial cells by genetic engineering methods.

Urethral mucosal sensitivity testing--a standardized contact medium

A standardized contact medium for urethral mucosal sensitivity testing is described. The effects of temperature, pulse width and composition of the urethral contact medium on the electrical characteristics of the system and the effect of changing composition of the medium on its lubricant properties are discussed. It is recommended that a 50:50 volume for volume mixture of KY jelly and normal saline be adopted as a standard in order to facilitate the comparison of results between groups working in this field.

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.

Effect of opiate analgesia and opioid blockade on urethral mucosal sensitivity threshold

The effect of opiate analgesics (omnopon, pethidine, pentazocine) on the urethral mucosal sensitivity threshold in 37 patients, and of the potent opiate/opioid antagonist naloxone on 10 volunteers is described. Omnopon and pentazocine caused a significant decrease in sensitivity (p less than 0.02) and naloxone caused a significant increase in sensitivity (p less than 0.02). The results confirm a role for the endogenous opioids in modulating urethral sensitivity, and the implications of this are discussed.

The end of the road: residential disposals in the Scottish children's hearings system

In a study of a representative sample of 301 "children's hearings", particular attention was given to 27 cases in which the child was committed to a List D school. Because the Scottish juvenile justice system has an explicit commitment to promoting the welfare of the children with whom it deals, the decisions were examined with special reference to the objectives that the hearing members hoped to achieve. These decisions could be divided into: (1) those which reflected only a sense that all alternatives had been exhausted; (2) those which aimed to ensure that the child received formal education or was placed in an environment which would help resolve his personal difficulties; (3) those designed to protect the child from family stresses or to achieve some other specific purpose. Since decisions under (1) are incompatible with the formal philosophy of the system, most of those under (2) entail no knowledge of the effectiveness of List D schools for the purposes in question, and some of those under (3) were wholly misconceived, it is concluded that there are some significant inconsistencies between the system's ideology and the actual practice of its members.