Is the establishment rate and fecundity of Haemonchus contortus related to body or abomasal measurements in sheep?

The relationship among parasitological parameters, abomasal size and body size measurements was investigated in lambs following an experimental infection with Haemonchus contortus. In total, 100 lambs from five different genotypes (German Merino (GM), Texel × GM, Suffolk × GM, German Blackhead Mutton × GM and Ile de France × GM) were experimentally infected with 5000 infective third stage larvae of H. contortus at the time of weaning at 12 weeks of age. Four and six weeks after infection, individual faecal samples were collected for estimation of faecal egg counts (FECs). Furthermore, wither height, shoulder width, heart girth, loin girth and body length were taken at 18 weeks of life. Lambs were slaughtered and necropsied 7 weeks post-infection, and worm counts, abomasal volume and surface area were determined. Positive correlations were found between different body size parameters, body weight and abomasal sizes. FEC and worm counts were not significantly correlated either with body size parameters or with abomasal size. The mean worm burden was higher in GM than in crossbred lambs. There was no significant difference in abomasal size between GM and crossbred lambs. The results suggest that the variations between animals in worm burden following an experimental infection with H. contortus (worm resistance) are not influenced by body size parameters or abomasal sizes. Therefore, other factors, including genetic-based differences in resistance, must cause these findings between and within breeds.     

High-performance liquid chromatographic determination of phenylephrine in human serum with coulometric detection

A high-performance liquid chromatographic method for the determination of phenylephrine (PE) in human serum using coulometric detection is described. PE and internal standard, orciprenaline, were extracted from serum by solid-phase extraction and separation achieved on a coupled column system consisting of two C₁₈ cartridge columns (250×4.6 mm I.D. coupled to a shorter 50×4.6 mm I.D. column) using a mobile phase of methanol-50 mM phosphate buffer (pH 3.2; 10:90) at 36°C. Dual electrode coulometric detection was used in the “oxidative screen” mode. Calibration curves were linear over the range 0.3–4 ng/ml with a limit of quantification (LOQ) of 0.35 ng/ml. The method has a greater degree of sensitivity, precision and accuracy compared to previously published methods for PE and is suitable for use in pharmacokinetic and bioequivalence studies in humans.     

Growth and differentiation of primary rat kerationocytes on synthetic membranes

Summary The attachment, proliferation, and differentiation of primary cultures of kerationcytes isolated from murine epidermis were monitored after purified cell suspensions were seeded and incubated in vitro on various synthetic membranes. Concomitant studies of the effects of attachment factors added to synthetic membranes before use as substrata for keratinocytes were also done. The study demonstrated that a synthetic membrane composed of nylon was superior to other membranes and to plastic control culture vessels in supporting the growth of murine keratinocytes. Although laminin enhanced initial attachment and proliferation of cells on nylon membranes, the untreated substratum was more effective for extended incubation. Stratification and differentiation of these kerationcytes on the nylon substratum was enhanced by raising confluent cultures (7 d) to the air-medium interface so that they were in contact with medium only from the bottom. Cultures raised for 14 d produced many morphologic markers of the epidermis and closely resembled the architecture of this tissue in situ. This investigation was supported in part by the Johns Hopkins Center for Alternatives to Animal Testing and by the United States Army Medical Research and Development command, contract DAMD17-82-C-2198. The views, opinions or findings contained in this report are those of the authors and should not be construed as position, policy or decision of the agency supporting the research.