Collection and cryopreservation of preimplantation embryos of Cavia porcellus.

Individual differences and a rather long-lasting reproductive cycle, as well as the relatively small number of oocytes that mature during one reproductive cycle makes it difficult to establish a cryopreserved stock of preimplantation embryos of the guineapig (Cavia porcellus) when compared with other laboratory rodents. Only a few data for superovulation protocols that can be used for routine laboratory use in guineapigs are available. However, a huge number of different strains exist for many purposes and the establishment of a frozen repository makes sense. Here, we describe the successful freezing of preimplatation embryos of the strain 2BS with a two-step freezing protocol in a freezing medium containing 1,2-propanediol as cryoprotectant. Human menopausal gonodotrophin induced superovulation in the embryo donors.

The epidemiology and control of primary amoebic meningoencephalitis with particular reference to South Australia.

This paper reviews the history, epidemiology and control of primary amoebic meningoencephalitis (PAM), caused by Naegleria fowleri, with particular reference to South Australia. The intention has been to outline misconceptions and uncertainties pervading the earlier literature. Although PAM infections elsewhere have been attributed to cysts in air-borne dust, we believe that contact with water in the domestic environment was not adequately considered as a potential source of these infections. Several reports have cast doubt on the effectiveness of chlorine in controlling N. fowleri, although there is laboratory and South Australian field experience to the contrary. These reports can be traced to a misunderstanding of the circumstances surrounding cases of PAM reported by other workers. Provided that a continuous free chlorine residual of 0.5 mg/l can be maintained in water accessible to N. fowleri, the risk of disease should be negligible. The failure of amphotericin B therapy to save recent victims of the disease, despite relatively prompt intervention, is disappointing. Possible reasons for this, and the reports that rifampin or tetracycline combined with amphotericin might be more successful, are discussed.

Do bicycle safety helmets reduce severity of head injury in real crashes?

In the past, evaluation of helmet efficacy has been based on laboratory tests of limited relevance to real crashes. In the present study 894 South Australian bicycling enthusiasts returned mail questionnaires about their most recent bicycle crash and their helmet use at the time. 197 bicyclists reported a crash within the past five years in which they had struck their head or helmet. Helmet status at the time of the crash was reported as: no helmet used (n = 75), hairnet-style helmet (n = 69), hard-shell with soft or no liner (n = 37), or hard-shell helmet with stiff liner (n = 16). Analysis of the crude, unadjusted data showed a statistically significant association between helmet use and reduced severity of head injury. The association persisted after adjustment for age and sex of rider, and severity of crash forces. Using an unpublished method developed by Somers, it was estimated that the risk of death from head injury was considerably reduced for helmeted relative to unhelmeted bicyclists, depending on helmet type.

Does preoperative administration of metamizol (Novalgin) affect postoperative body weight and duration of recovery from ketamine-xylazine anaesthesia in mice undergoing embryo transfer: a preliminary report.

Thirty-two female mice used for embryo transfer or as controls received either metamizol or equal volumes of normal saline administered subcutaneously following induction of anaesthesia with ketamine-xylazine. Body weight was measured immediately before surgery, after 24 and after 48 h. The duration of the surgical anaesthesia was recorded and postoperative behavioural responses were measured. Comparison of the treatment groups revealed no significant differences in body weight and recovery times, nor were other signs of discomfort detected in either treatment group. It was concluded that administration of metamizol did not provide additional analgesia following embryo transfer in mice anaesthetized with ketamine-xylazine.

A comparison of Australian suicide rates in 1969-73 and 1976-80.

Australian suicide rates were compared for the 1969-73 and 1976-80 periods by age, sex and State. Rates for males were generally at least twice those for females. The sex difference was marked, irrespective of age, State and time period. Middle-aged and older Australians generally had higher rates than 20-29-year-olds, although this finding was not consistent by State for males. The national age-standardised suicide rate for all age groups combined decreased between the 1969-73 period and 1976-80 both for males and (more so) for females. However, there was a 24% increase for 20-29-year-old males. While the suicide rate for 20-29-year-old females decreased between the 1969-73 period and 1976-80, an analysis of yearly trends within the 1976-80 period revealed an upward trend for individuals aged 20-29 years, for both females and males.

The effectiveness of invitations from general practitioners in recruiting women to mammographic screening.

OBJECTIVE: To evaluate the effectiveness of general practitioner patient lists as a means of recruiting women to mammography screening. DESIGN: This study constitutes the first part of a comparative study of two alternative recruitment strategies involving invitation of women identified from: (i) general practitioner lists; and (ii) the electoral roll. SETTING AND SUBJECTS: The subjects were women aged 50-64 listed as patients of the first three private practices that agreed to collaborate with the South Australian (SA) Breast X-Ray Service to recruit by this method. These practices include five locations encompassing a spread of middle and upper class socioeconomic areas in Adelaide's southern suburbs. INTERVENTIONS: In all, 1505 women who had not already attended the SA Breast X-Ray Service were sent a letter of invitation by their general practitioner to attend the Service for a screening mammogram at a specified date and time. MAIN OUTCOME MEASURES: The primary outcome measures were eligibility status (eligible, not eligible) and attendance status (attended, cancelled appointment, failed to attend without notice). RESULTS: Excluding 34 letters that were returned unopened, 10% of invitees were classified as not eligible, mostly because they had had a recent mammogram elsewhere. Of the remaining invitees, 68.6% attended, 8.4% rang to cancel the appointment and 23% failed to attend without prior notice. CONCLUSIONS: This method of recruitment is viable, and it yields high participation rates close to the "Health for All Australians" target of 70% for mammography screening. Furthermore, the actual attendance rate for this population is expected to increase over time, because some of those initially classified as ineligible, or who cancelled or failed to attend, eventually will attend. The success of this method of recruitment will be measured against the relative cost and effectiveness of the electoral roll alternative, currently under investigation by the SA Breast X-Ray Service.

Head injuries in country and city. A study of hospital separations in South Australia.

The incidence of head injury in South Australia was estimated from hospital separation (discharges, transfers and deaths) data for 1980 and 1981. The rate of hospital separation of patients with head injury in these years was high by international standards, and was 33% greater for country residents than for residents of the Adelaide metropolitan area. Marked differences in separation rates were observed between different age, sex and occupational groups. On the basis of indirect measures of injury severity, the injury severity threshold for admission to hospital with head injury appeared to be similar in country and city hospitals. An attempt was made to estimate the number of people seriously disabled by head injury each year. The findings raise questions about the concentration of acute surgical and long-term rehabilitation services in the city, at the expense of country areas; they also provide a starting point for further, analytical studies of head injury.

Birth defects and household water supply. Epidemiological studies in the Mount Gambier region of South Australia.

We report a descriptive study indicating a localised excess of congenital malformations in Mount Gambier, South Australia, and summary results of a subsequent case-control study showing an association between the occurrence of congenital malformations and the consumption of underground water by pregnant women. The internal cohesion of the data analyses, and the plausibility conferred by experimental evidence, suggests that the underground water, and its elevated concentration of nitrates, may warrant further consideration as a source of human teratogens.

Congenital malformations and maternal drinking water supply in rural South Australia: a case-control study.

A case-control study, carried out in the Mount Gambier region of South Australia, investigated the relationship between mothers' antenatal drinking water source and malformations in offspring. It was prompted by earlier descriptive findings of a statistically significant, and localized, increase in the perinatal mortality rate in Mount Gambier, due principally to congenital malformations affecting the central nervous system and multiple organ systems. Available for statistical analysis were 218 case-control pairs, from the period 1951-1979, individually matched by hospital, maternal age (+/- 2 years), parity and date of birth (+/- 1 month). Compared with women who drank only rainwater during their pregnancy (relative risk (RR) = 1.0), women who consumed principally groundwater had a statistically significant increase in risk of bearing a malformed child (RR = 2.8). Statistically significant risk increases occurred specifically for malformations of the central nervous system and musculoskeletal system. Reanalysis of the data by estimated water nitrate concentration demonstrated a nearly threefold increase in risk for women who drank water containing 5-15 ppm of nitrate, and a fourfold increase in risk for those consuming greater than 15 ppm of nitrate. A seasonal gradient in risk was evident among groundwater consumers, ranging from 0.9 for babies conceived in winter, 3.0 in autumn, to 7.0 and 6.3 for spring and summer conceptions, respectively. Linear logistic regression analysis, controlling for risk factors not accounted for in the study design, showed that maternal water supply, infant's sex, and mother's area of residence all contributed significantly to the risk of malformation. These results are discussed in relation to previous experimental and human descriptive studies, suggesting a plausible mechanism for nitrate-induced teratogenesis.