Slow horizontal head and body rotation occurs in mice and rats when the visual field is rotated around them, and these optomotor movements can be produced reliably in a virtual-reality system. If one eye is closed, only motion in the temporal-to-nasal direction for the contralateral eye evokes the tracking response. When the maximal spatial frequency capable of driving the response ("acuity") was measured under monocular and binocular viewing conditions, the monocular acuity was identical to the binocular acuity measured with the same rotation direction. Thus, the visual capabilities of each eye can be measured under binocular conditions simply by changing the direction of rotation. Lesions of the visual cortex had no effect on the acuities measured with the virtual optokinetic system, whereas perceptual thresholds obtained previously with the Visual Water Task are. The optokinetic acuities were also consistently lower than acuity estimates from the Visual Water Task, but contrast sensitivities were the same or better. These data show that head-tracking in a virtual optokinetic drum is driven by subcortical, lower frequency, and contralateral pathways.

Animals↗

PubMedDate not supplied

An epidemiologic approach to pneumococcal disease.

In many countries of the developing world, pneumonia remains a leading cause of morbidity and premature mortality. In their quest for effective control measures not dependent on the socioeconomic changes in Western societies that have paralleled a reduction in mortality from pneumonia, these poorer countries are looking towards modern antibiotic therapy and pneumococcal vaccines as short-term approaches to the problem. This paper summarizes information about the response of human populations to Streptococcus pneumoniae with particular reference to the author's experience in Papua New Guinea, where penicillin resistance is an increasing problem and where pneumococcal vaccines have been shown in field trials to reduce mortality from respiratory disease among both adults and children. In each developing country, basic epidemiologic data are needed to assist in choosing the best available combination of strategies for control of disease due to S. pneumoniae. Our current understanding of the determinants of pneumococcal carriage and pneumococcal disease is still inadequate, however, and there is need for studies of the interaction of the pneumococcus and its host at the mucosal surface to better understand the differences in the behavior observed for the various serotypes.

Adolescent↗

PubMedDate not supplied

The K(+)-efflux system, KefC, in Escherichia coli: genetic evidence for oligomeric structure.

KefC is a glutathione-gated K(+)-efflux system that is widespread in Gram-negative bacteria and which plays a role in the protection of cells from the toxic effects of electrophilic reagents, such as N-ethylmaleimide (NEM). The KefC gene from Escherichia coli has been cloned and the DNA sequenced. A number of kefC mutants that affect K+ retention by the KefC system have been isolated and all retain activation by NEM. Cloned kefC was found to suppress the phenotype of two such mutants kefC121 and kefC103. Analysis of this phenomenon has shown that suppression is specific to the KefC system, but that cloned kefC from Klebsiella and Erwinia can also mediate suppression of the mutant phenotype. Plasmid constructs of the E. coli gene in which expression of the cloned gene was diminished showed induced ability to suppress the mutant phenotype. KefC'-'LacZ hybrid proteins were inserted in the membrane but did not suppress the mutant phenotype. Cloned kefC did not suppress a mutant kefB allele that exhibited a similar phenotype to the kefC121 allele. These data suggest that suppression is unlikely to arise from exclusion of the mutant form of the protein from the membrane. Furthermore, NEM-activated K+ efflux from a strain carrying both the mutant and cloned wild-type alleles was faster than when either allele was present in cells alone, suggesting that both forms of the protein are inserted into the membrane. These data are discussed in terms of a model for the KefC protein in which the protein is composed of one or more identical subunits that interact in the membrane.

Bacterial Proteins↗

PubMedDate not supplied

Publication of utilisation data. Its effect on clinical decisions.

During an 18-week period in 1978-1979, a weekly bulletin containing information about patients' stay in hospital and prescribing patterns in each unit was distributed to all doctors and senior nurses of six general medical and six general surgical units in the Royal Adelaide Hospital. For the first nine weeks, the bulletins contained information from half of the units, then crossed over in the second nine-week period. The mean stay in all units of 2251 persons discharged from hospital during the first nine weeks was 9.5 days, compared with 8.7 days for the 2234 patients in the second nine weeks (a reduction of more than 2000 bed-days (P less than 0.002)). The percentage of outpatients and discharged inpatients who were given prescriptions for more than two drugs fell from 15.3% to 13% (P less than 0.001). It is likely that publication of the bulletins influenced discharge and prescribing decisions by increasing general awareness that these matters were under review.

Australia↗

PubMedDate not supplied

Chinese herbal medicines in the treatment of acute respiratory infections: a review of randomised and controlled clinical trials.

OBJECTIVE: To review clinical trials of Chinese herbal medicines (CHMs) in the management of acute respiratory infections (ARIs). DATA SOURCES: MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library and three Chinese medical journals available in Australia. STUDY SELECTION: Studies in which a control group was used in comparing CHMs with a placebo or "Western medicine" (usually antibiotics) for treating ARIs were included. DATA SYNTHESIS: 27 of 46 studies identified in the search of the databases and the Chinese journals fulfilled the inclusion criteria. Twenty-six of these were published in Chinese, and one in English. Twenty were randomised controlled trials and seven were "controlled clinical trials". Although most of the studies reported that CHMs are better than antibiotics for the treatment of ARIs, the quality of the studies was generally poor when evaluated for patient allocation, treatment description, outcome measurement and data analysis. CONCLUSIONS: Because the trial methodology of these studies was often inadequate or insufficiently documented, it is difficult to recommend the use of CHMs in ARIs. However, Shuang Huang Lian does appear to be useful for treating lower respiratory tract infections. More rigorous evaluation of CHMs is needed, as they are becoming popular treatments in many countries, including Australia.

Acute Disease↗