鄱阳湖钉螺体内吸虫尾蚴记述

作者从1999-2000年共解剖鄱阳湖草洲钉螺87146只，先后发现裸头类、矛口类、单盘类、微尾类、叉尾类、对盘类、无尾类尾蚴共15种，本文将各种尾蚴的形态特征予以简介。     

Suppression of lymphocyte blastogenesis by porcine interferon-α

Peripheral blood lymphocytes (PBL) from five four-day-old and five six-week-old piglets were treated with 10 to 320 units of porcine interferon-alpha, and their blastogenic responses to phytohaemagglutinin or pokeweed mitogen were compared with those of control lymphocytes. There was significant inhibition of the blastogenic response to phytohaemagglutinin by 320 units of interferon-alpha, and of the response to pokeweed mitogen by 320 and 160 units of interferon-alpha. Porcine interferon-beta was cytotoxic to porcine PBL. The blastogenic response to pokeweed mitogen was significantly higher in PBL from the younger piglets.     

Do summer temperatures trigger spring maturation in Pacific lamprey,Entosphenus tridentatus?

Abstract –  Pacific lamprey, Entosphenus tridentatus , return to streams and use somatic energy to fuel maturation. Body size decreases, the lamprey mature, spawn, and then die. We predicted that warm, summer temperatures (>20 °C) would accentuate shrinkage in body size, and expedite sexual maturation and subsequent death. We compared fish reared in the laboratory at diel fluctuating temperatures of 20–24 °C (mean = 21.8 °C) with fish reared at cooler temperatures (13.6 °C). The results confirmed our predictions. Lamprey from the warm water group showed significantly greater proportional decreases in body weight following the summer temperature treatments than fish from the cool water group. A greater proportion of warm water fish sexually matured (100%) and died (97%) the following spring than cool water fish (53% sexually mature, 61% died). Females tended to mature and die earlier than males, most obviously in the warm water group.     

Wildebeest-derived malignant catarrhal fever: unusual epidemiology in South Africa

The epidemiology of wildebeest-derived malignant catarrhal fever in South Africa differs from the worldwide accepted pattern. Here the occurrence of the disease is often not related to close contact between cattle and wildebeest, and most cases are observed during late winter and spring, when wildebeest calves are 8-10 months old. This is in contrast to the situation in Kenya and Tanzania, where most cases are encountered during autumn, when wildebeest calves are 3-4 months old.     

Algunos aspectos sobre la inervación de pulmon en animales de laboratorio

The finer innervation of the tissues of the lung was studied with several methods of silver impregnation, focussing especially on the fibers and endings of the nerves. The richest terminal innervation could be found in the epithelial and subepithelial tissue, and was sometimes similar to the situation in the smooth muscles which might indicate that, somehow, secretory and motor innervation are alike morphologically. On the other hand, there were many nerve fibers in the perichondrium of the small nodules and plaques of cartilage too, although they did not enter the cartilaginous tissue. The final nerves ended in different forms, from round or ovoid masses to free "ultraterminal" filaments.     

A bio-economic modelling project for small-scale milk production systems in South-East Brasil

This paper reports on the development and use of a bioeconomic model to simulate dairy enterprises in the Zona da Mata of Minas Gerais State in south-east Brasil.In view of the relatively small size of the units, each animal within the herd is accounted for on an individual basis and the main biological events and processes are treated stochastically. Within the limits of given herdranges for genetic potentials, actual rates of performance are estimated from the levels of feeding and other management factors. An energy balance approach is used to assess the contributions of pasture, cut forage and concentrates in the diet.The model has been used to help in identifying priority areas for applied research, to explore various combinations of herd potential and level of feeding, the behaviour of different herd sizes and the potential returns from specific technical innovations.     

Fimbria-like adhesive factor (EAF 44) from verocytotoxigenic Escherichia coli of bovine origin

An adhesin with fimbria-like properties was present in four strains of verocytotoxigenic Escherichia coli isolated from diarrhoeic calves in Brazil.     

Immunization of cattle with Anaplasma marginale derived from tick cell culture.

Anaplasmosis is a hemolytic disease of cattle caused by the ehrlichial tick-borne pathogen Anaplasma marginale. Killed vaccines used for control of anaplasmosis in the US used antigen harvested from infected bovine erythrocytes which was often contaminated with bovine cells and other pathogens. In this study, we performed an initial cattle trial to test A. marginale harvested from tick cell culture as an immunogen for cattle. Eleven yearling Holstein cattle were immunized with the cell culture-derived A. marginale and 11 cattle were non-immunized contact controls. Each vaccine dose contained approximately 2 x 10(10) A. marginale in an oil-based adjuvant. Two immunizations were administered subcutaneously 4 weeks apart and the cattle were challenge-exposed 10 weeks after the second immunization with A. marginale infected blood. Maximum antibody levels as determined by an A. marginale specific competitive ELISA were observed 2 weeks after the last immunization. Antibody responses against major surface proteins (MSPs) 1a and 1beta1 were also characterized and immunized cattle demonstrated a preferential recognition for MSP1beta1. Cattle immunized with the cell culture-derived A. marginale had a significantly lower percent reduction in the packed cell volume (P<0.05) after challenge exposure as compared with the controls and did not display clinical anaplasmosis. The cell culture-derived A. marginale shows promise for use as antigen in development of a new killed vaccine for anaplasmosis.     

Consideraciones sobre el sistema urinario del Gallus gallus– Indian River; I. Formación y tributaris del uréter

In the literature reviewed, there are certain differences of opinion with regard to the formation and tributareis to the ureter. Therefore, dissection of 40 fowls injected with neoprene latex, k neoprene latex and celobar (radiopaque mass) and vinyl acetate casts through the ureter and blood vessels revealed the formation and disposition of the tributaries to the ureter, and its origin and number of collectors. The results were described in relation to the renal lobes.