Occurrence of subgroup J avian leukosis virus in Taiwan.

There are three grandparent farms for three different chicken breeds in Taiwan. One of these farms, populated by breast meat yield chickens (yield type), suffered from a severe subgroup J avian leukosis virus (ALV-J) infection in mid-1997. The affected flocks at that farm had a weekly mortality of more than 1% and a 15% drop in egg production. The broilers from that breed had a 10% condemnation rate during the first week of age, and 5% of the remaining broilers were stunted afterwards. Some chickens had myeloid leukosis lesions at 6 weeks old. Their survivability was about 85%. However, chickens at the other two grandparent farms, populated with non-yield chickens (regular type), were also infected by ALV-J and showed myeloid leukosis. However, chickens at these farms produced progeny whose survivability reached more than 95%. ALV-J caused greater economic loss in yield type chickens than in regular type chickens in Taiwan.

Atrial natriuretic peptide-like immunoreactivity in neurons and astrocytes of human cerebellum and inferior olivary complex.

Atrial natriuretic peptide (ANP) has previously been localized in areas of mammalian brain associated with olfaction, cardiovascular function, and fluid/electrolyte homeostasis. Despite the presence of several types of natriuretic peptide receptors in mammalian cerebellum, neither intrinsic nor extrinsic sources of the natriuretic peptides have been described. In this report we describe the immunohistochemical localization of both intrinsic and extrinsic sources for ANP in human cerebellum. ANP-like immunoreactivity (ANP-LIR) was observed in climbing fibers in the cerebellar molecular layer that probably originated from isolated immunopositive neurons of the inferior olivary complex. Intrinsic sources of ANP-LIR included small subpopulations of protoplasmic and fibrous astrocytes and Bergmann glia, as well as Golgi and Lugaro neurons of the granule cell layer. These results suggest that, in addition to its presumptive roles in local vasoregulation, ANP may serve as a modulator of the activity of Purkinje neurons.

Characterization of the biologic activities of a recombinant human zona pellucida protein 3 expressed in human ovarian teratocarcinoma (PA-1) cells.

OBJECTIVE: This study was undertaken to clone and express a recombinant human zona pellucida protein 3 and to characterize its biologic activities as a sperm ligand and an inducer of the acrosome reaction. STUDY DESIGN: Human ovarian teratocarcinoma (PA-1) cells were transfected with an expression vector containing human zona pellucida protein 3 complementary deoxyribonucleic acid with a sequence coding for a 6-histidine tail introduced into its 3' end. Purification of the secreted glycoprotein was performed by sequential affinity (lectin and nickel--nitrilotriacetic acid) and ion-exchange chromatography. RESULTS: Western blot analysis confirmed a molecular weight of approximately 65 kd for the purified product. A cell-free translation system revealed a correctly sized protein backbone of 47 kd. The recombinant human zona pellucida protein 3 demonstrated specific, potent, and dose-dependent competitive inhibition of sperm-zona pellucida binding in vitro under hemizona assay conditions. Recombinant human zona pellucida protein 3 also stimulated the acrosome reaction of live sperm. This effect was fast, dose dependent, and capacitation time dependent. Furthermore, advance incubation with pertussis toxin, an inactivator of heterotrimeric G proteins, blocked recombinant human zona pellucida protein 3--induced acrosomal exocytosis. CONCLUSION: The recombinant human zona pellucida protein 3 expressed in PA-1 cells manifested the full spectrum of expected biologic activities. It therefore represents a valuable tool for examination of human fertilization and the design of new strategies in diagnosis of male factor infertility and in contraception.