Analysis of the TSC1 and TSC2 genes in sporadic renal cell carcinomas.

The genetic events involved in the aetiology of non-clear-cell renal cell carcinoma (RCC) and a proportion of clear cell RCC remain to be defined. Germline mutations of the TSC1 and TSC2 genes cause tuberous sclerosis (TSC), a multi-system hamartoma syndrome that is also associated with RCC. We assessed 17 sporadic clear cell RCCs with a previously identified VHL mutation, 15 clear-cell RCCs without an identified VHL mutation and 15 non-clear-cell RCCs for loss of heterozygosity (LOH) at chromosomes 9q34 and 16p13.3, the chromosomal locations of TSC1 and TSC2. LOH was detected in 4/9, 1/11 and 3/13 cases informative at both loci. SSCP analysis of the whole coding region of the retained allele did not reveal any cases with a detectable intragenic second somatic mutation. Furthermore, RT-PCR analysis of TSC1 and TSC2 on total RNA from 8 clear-cell RCC cell lines confirmed expression of both TSC genes. These data indicate that biallelic inactivation of TSC1 or TSC2 is not frequent in sporadic RCC and suggests that the molecular mechanisms of renal carcinogenesis in TSC are likely to be distinct.

Molecular analysis of the TSC1 and TSC2 tumour suppressor genes in sporadic glial and glioneuronal tumours.

Reduced expression of the TSC2 tumour suppressor gene product, tuberin, has been reported in sporadic astrocytomas, suggesting that the TSC genes may play a role in formation of sporadic glial or glioneuronal tumours. We studied paired constitutional and tumour DNA samples from 100 patients with sporadic glial and glioneuronal tumours for loss of heterozygosity (LOH) at the TSC1 and TSC2 loci using a combination of seven previously reported and seven novel polymorphic markers. LOH was seen in 1/16 astrocytomas, 3/15 ependymomas, 5/16 gangliogliomas, 2/14 glioblastoma multiforme, 0/7 oligodendrogliomas, 0/7 tumours of mixed oligodendrocytic/astrocytic histology, 2/11 pilocytic astrocytomas and 0/1 subependymal giant cell astrocytomas informative at both loci. However, SSCP screening of all coding exons of the TSC1 or TSC2 genes in the tumours displaying LOH, and of both genes in 21 gangliogliomas, revealed no intragenic mutations. The lack of demonstrable inactivation of both alleles of either TSC gene in any of the tumours investigated suggests that they do not play a frequent role in the aetiology of sporadic glial or glioneuronal tumours.

A 6-month home usage trial of a 1% chlorhexidine toothpaste (II). Effects on the oral microflora.

The effects of 1% chlorhexidine and 1% chlorhexidine/fluoride dentifrices on supragingival plaque flora were investigated in a 6-month home-usage study. 146 subjects were studied from whom plaque around 6 teeth was collected at baseline, 6 weeks and 24 weeks. Total anaerobic counts were reduced at 6 and 24 weeks in both active groups compared to control. No differences were seen in any other bacterial parameters. There was a significant decrease in the susceptibility to chlorhexidine of bacteria recovered from the subjects on the active treatments compared to control but, since the magnitude of effect was less than one dilution, this was not thought to be of any clinical significance.

A comparison of delmopinol and chlorhexidine on plaque regrowth over a 4-day period and salivary bacterial counts.

Delmopinol has been considered as a potential agent for the chemical control of plaque. The aims of these studies were to measure the effects of a 0.2% delmopinol hydrochloride mouthrinse on (1) plaque reformation and (2) salivary bacterial counts. Comparisons were made with a 0.2% chlorhexidine rinse and a placebo rinse. A group of 12 male volunteers took part in the plaque study which was of a double blind, randomised, 3 cell, cross-over design. From a zero plaque baseline subjects rinsed, 2x a day, under supervision, for 1 min with 10-ml volumes of the allocated rinse. After 4 days, during which no other form of oral hygiene was performed, plaque was scored by area and index. Plaque results were significantly lower with chlorhexidine and delmopinol compared with control, and with chlorhexidine compared to delmopinol. Side-effects with delmopinol were transient tingling and numbness of the tongue in some subjects. A 2nd group of 12 male volunteers received single, 1-min rinses of the 3 formulations. Salivary bacterial counts were determined immediately before and up to 420 min after rinsing. Compared to the control rinse, chlorhexidine significantly reduced bacterial counts of 420 min. Delmopinol produced a small reduction in bacterial counts which was only significantly different from control at one time point. Delmopinol deserves further evaluation as a chemical plaque inhibitor, particularly when used as an adjunct to normal toothcleaning.

The regulation of medical laboratories in Australia.

Australia has had a system of compulsory accreditation and inspection of medical laboratories since 1986. This article details the regulations that have evolved over the years and the specific requirements of this system. The importance of separation of powers of various authorities, including standards, accreditation, payment, inspection, quality assurance, and education, is emphasized.

Assessment of physicians' office pathology testing: organisational considerations.

In this paper we consider organizational and design aspects of an assessment of physicians' office pathology testing, and discuss difficulties in measuring the level of performance and effectiveness of such diagnostic services. A major consideration is the trade-off between compliance with a well-defined protocol, and use of the technology in a way which resembles normal operating practice.

An assessment of the prevalence of hepatitis B among health care personnel in Victoria.

The prevalence of past infection with hepatitis B virus in health care personnel was investigated by questionnaire and by a serological survey of personnel in a representative selection of Victorian hospitals and institutions. According to the available data, hepatitis B does not appear to have been a major infection problem among health care personnel in Victoria. The only occupational group that clearly is at an increased risk of acquiring the infection is the dental profession. Nursing staff members in institutions for the mentally retarded may also be at a higher risk. The findings of this investigation were used as a basis to frame recommendations for the vaccination of health care workers in Victoria against hepatitis B.

Ranitidine and placebo in the treatment of reflux oesophagitis. A double-blind randomized trial.

A study was carried out to assess the effectiveness of ranitidine in the short-term treatment of reflux oesophagitis. In a double-blind randomized trial of 37 outpatients with symptomatic, endoscopically proven, moderate or severe reflux oesophagitis, 18 patients received ranitidine (150 mg twice a day) and 19 patients received identical-looking placebo tablets for a period of six weeks. Clinical, laboratory, and endoscopic assessments were made initially, and at the end of six weeks. Two patients withdrew during the trial. Endoscopic evidence of improvement was found in 15 of 17 ranitidine-treated and in five of 18 placebo-treated patients. This difference was significant (P less than 0.01). Antacid consumption was significantly lower in the ranitidine-treated group (P less than 0.01). Improvement in histological findings, and the relief of retrosternal pain, regurgitation, dysphagia, and epigastric pain did not achieve levels of statistical significance. No adverse clinical or laboratory changes occurred in patients in either group. It is concluded that, as judged by endoscopic evidence, ranitidine is an effective drug for the short-term treatment of reflux oesophagitis.