Ultrasonography of the female reproductive organs in farmed ostriches (Struthio camelus spp.)

The main objective of this study was to determine whether transcutaneous ultrasonography could be used as a diagnostic tool to monitor the reproductive organs of female breeding ostriches. An additional aim was to investigate whether the use of this technique could facilitate prediction of the start or end of the egg production season. A technique for on-farm ultrasound scanning is described and examples of ultrasonographic images of different ovarian structures, developing ova and eggs within the genital tract are presented. These data were obtained by scanning mature female breeding ostriches (n=8). In vivo scanning took place a day prior to slaughter, and immediately after slaughter the reproductive organs were scanned in vitro in a water bath. By comparing ultrasonographic images with post mortem ovarian morphology, it appeared that the following morphological structures can be identified using ultrasonography: ovarian follicles of different sizes (diameter (phi) 1-9 cm), atretic follicles, post-ovulatory follicles (POFs), ova at different stages of development and eggs within the genital tract. Of the number of follicles counted during post mortem investigation, 58% (95% confidence interval 0.41-0.79) had been detected during previous in vivo examination. In the second part of our study, ultrasonographic scans were made at weekly intervals in two farmed female ostriches (n=2) during the breeding season in order to determine the predictive value of the technique. By comparing the images of ovarian activity with individual egg production of these hens, preliminary evidence was obtained that scanning might be of value in predicting egg production, especially at the start and the end of the breeding season. It is concluded that transcutaneous ultrasound scanning in mature female breeding ostriches is an easy, noninvasive technique for the monitoring of ovarian (in)activity, for visualization of different functional ovarian structures, for following the development of individual ova and for visualization of an egg with calciferous shell within the oviduct, and that this technique will be a valuable tool in future research on reproductive physiology and pathology, and the development of more advanced reproductive technologies, such as artificial insemination.     

Divergent effects of leptin on luteinizing hormone and insulin secretion are dose dependent

We have shown recently that fasting permits leptin to modulate both luteinizing hormone (LH) and insulin secretion in cows. In rodents, leptin causes divergent effects on LH and insulin release that are dose dependent. To test the hypothesis that leptin effects on LH and insulin secretion in fasted cows are dose related, we examined the effects of various doses of recombinant ovine leptin (oleptin) in mature cows. Twenty ovariectomized beef cows, each bearing an estradiol implant to maintain basal estradiol concentrations, were used. All cows were fasted for 60 hr with free access to water and were assigned randomly to one of four groups (n = 5/group): 1) saline control; 2) leptin, 0.2 microg/kg; 3) leptin, 2.0 microg/kg; and 4) leptin, 20 microg/kg body wt. Blood samples were collected at 10-min intervals for 6 hr on Days 0 and 2, with saline or oleptin injected intravenously immediately after the first intensive sample on Day 2 (54 hr). Leptin caused a dose-related increase (P < 0.001) in mean concentrations of circulating LH. Stimulation of LH release by leptin was significant at the lowest (141% of control) and middle (122% of control) doses used, but no increase was observed for the highest dose. Increased mean concentrations of LH appeared to result from an augmentation of basal secretion, as pulse characteristics were not affected. After 54 hr of fasting, plasma insulin concentrations were lowered (P < 0.01) in all treatment groups compared to Day 0. After leptin injections, plasma insulin concentrations increased (P < 0.01) and reached highest concentrations during the first hour of sampling. However, this increase was sustained for several hours only in the intermediate (2.0 microg/kg) dose group. Collectively, our results show that leptin has potent positive effects on both LH and insulin secretion in fasted cows, but the anterior pituitary and endocrine pancreas appear to become downregulated in the presence of excess ligand.     

Molecular monitoring in malaria vaccine trials

Molecular techniques offer new approaches for malaria field trials, particularly PCR techniques, which facilitate accurate diagnosis of Plasmodium infections and increase the power of estimates of vaccine effects on malaria prevalence or incidence. Molecular methods also help to assess selective effects of vaccines. Longitudinal genotyping data can be used to initiate novel analyses of parasite dynamics, including estimates of incidence of infection with individual parasite clones and duration of infections. In addition, high-throughput methods can be used to apply these techniques routinely in randomized controlled trials, as well as programme-based evaluations of malaria control.     

Mapping of lymphatic filariasis in Nepal

BACKGROUND: Human infection with Wuchereria bancrofti causes a disabling parasitic disease known as lymphatic filariasis, which is a major public health and socio-economic problem in many parts of the world. At the onset of the study, little was known of the distribution of filariasis and its current importance as a public health problem in Nepal. METHODS: Epidemiological mapping was undertaken to determine the prevalence of infection by Wuchereria bancrofti in 37 districts of Nepal between July to December 2001. The study population above 15 years of age was selected, and the immunochromatographic test (ICT Filariasis) was used to screen for circulating filarial antigen (CFA). RESULTS: The overall prevalence of lymphatic filariasis from a 4,488-sample population was 13% and 33/37 districts were found to be endemic. On the basis of geographical data, the highest number of cases was found at altitudes between 500-700 m; however, a substantial number of infected individuals were found in the highly populated Kathmandu valley, at altitudes between 900-1,500 metres where transmission appears to take place. Prevalence rates above 20% were found in 11 districts (with the highest rate of 40%), 6-19% were found in 15 districts, and 0.1-5% were in 7 districts.Information on people's knowledge, attitudes and behaviour towards filariasis was also collected by means of a structured questionnaire, which is presented and discussed in the study. CONCLUSIONS: This is the most extensive study of lymphatic filariasis undertaken to date in Nepal. The study indicates that the prevalence of infection is far greater that was previously reported and that lymphatic filariasis should be a much higher health priority than currently given.     

Suppression of exonucleolytic degradation of double-stranded DNA and inhibition of Exonuclease III by PNA

Degradation of double-stranded DNA by Exonuclease III in the presence of complementary anti-parallel PNA was studied. It was found for the first time that the PNA suppresses the degradation of dsDNA in a sequence-specific manner as well as inhibits the activity of Exonuclease III in a non-specific way.     

Futility without a dichotomy: towards an ideal physician-patient relationship

The futility debate may be considered as an effort to provide a clear and justified borderline between physician and patient decision–making authority. In this paper we argue that the search for a definition of futility that provides physicians with a final argument in discussions about life–prolonging treatment, is misplaced. An acceptable and meaningful criterion of futility that satisfies this effort seems impossible. As a consequence, we reject a dichotomous domain of decision–making power as the starting point for definitions of futility. A good decision about withholding life–sustaining treatment should be justified from the perspectives of both physician and patient. In this light, a range of definitions of futility is still useful as it can clarify intuitions that a treatment is inappropriate.     

A method to estimate acetylcholinesterase-active sites and turnover in insects

Acetylcholinesterase is the primary target of organophosphorous and carbamate insecticides. Quantitative changes in acetylcholinesterase are suspected to confer resistance to these insecticides, but a method to estimate the amount in insect is not available. A method using irreversible inhibitors has been developed. Among the irreversible inhibitors tested, 7-(methylethoxyphosphinyloxy)-1-methylquinolinium iodide, chlorpyrifos-ethyl-oxon, and coumaphos-oxon were found to be sufficiently potent and specific.     

Induced Response of Tomato Plants to Injury by Green and Red Strains of Tetranychus Urticae

We studied the induced response of tomato plants to the green strain and the red strain of the spider mite Tetranychus urticae. We focused on the olfactory response of the predatory mite Phytoseiulus persimilis to volatiles from T. urticae-infested tomato leaves in a Y-tube olfactometer. Tomato leaves attracted the predatory mites when slightly infested with the red strain, or moderately or heavily infested with the green strain. In contrast, neither leaves that were slightly infested with green-strain mites, nor leaves that were moderately or heavily infested with the red strain attracted the predators. We discuss the specific defensive responses of tomato plants to each of the two strains.