Changes of calbindin D-28k immunoreactivity in the hippocampus after adrenalectomy in the seizure sensitive gerbil

Calbindin D-28k (CB), a calcium-binding protein, containing neurons in the hippocampus plays an important role in hippocampal excitability in epilepsy. In the present study, we investigated changes of CB immunoreactivity after adrenalectomy (ADX) in the hippocampus and dentate gyrus of the seizure sensitive gerbil, which is susceptible to seizure to identify roles of CB in epileptogenesis. The changes of the CB immunoreactivity after ADX were significant in the hippocampal CA1 region. By 24 h after ADX, CB-immunoreactive CA1 pyramidal cells and CB immunoreactivity increased. At this time, well-stained dendrites projected to the stratum radiatum. Thereafter, the CB immunoreactivity decreased time dependently by 96 h after ADX. In the dentate gyrus, the changes of CB-immunoreactive neurons were mainly observed in the granule cell layer. The number and immunoreactivity of CB-immunoreactive neurons was high at 24 h after ADX, thereafter, those decreased by 96 h after ADX. These results suggest that glucocorticoid has an important role in modulating the seizure activity and CB serves an inhibitory function, which regulates the seizure activity and output signals from the hippocampus.     

Histochemical study on neurodegeneration in the olfactory bulb after transient forebrain ischaemia in the Mongolian gerbil

In the present study, we investigated the ischaemia-related neurodegeneration in the main and accessory olfactory bulb (AOB) after 5 min transient forebrain ischaemia in the Mongolian gerbil using the acid fuchsin staining method. Between 5 and 15 days after ischaemia, acid fuchsin positive cells markedly increased in the external plexiform layer (EPL), mitral cell layer (ML) and glomerular layer (GL) of the main olfactory bulb (MOB), and in the mixed cell layer (MCL) and GL of the AOB. By 30 days after ischaemia reperfusion, acid fuchsin positive neurons were shrunken and showed low acidophilia in somata. Many necrotic vacuoles were found in the EPL and GL of the MOB 30 days after ischaemia. At this time, necrotic vacuoles were very few in the AOB. Therefore, our results suggest that the GL and EPL of the MOB are vulnerable to ischaemic damage at a later time after ischaemic insult, and that the AOB is more resistant to ischaemic damage as compared with the MOB.     

Fetal bladder outlet obstruction in a stillborn bovine fetus

A stillborn bovine male fetus with abdominal distention, arthrogryposis and atresia ani was presented for diagnostic evaluation. At necropsy, this fetus had a large amount of ascites, urachal obstruction and marked bladder distention. The ventral surface of the bladder had ruptured and attached to the abdominal wall by fibrinous adhesions. There was bilateral hydronephrosis with moderate pelvic dilatation and cortical attenuation. The rectum was filled with meconium but the anus was imperforate. The right forelimb was contracted. The cause(s) of these abnormalities could not be determined; however, we believe that developmental abnormalities during embryogenesis may be the result of chromosomal abnormalities.     

Spontaneous complex odontoma in a Sprague-Dawley rat

Complex odontoma from a female Sprague-Dawley rat is described histopathologically. Necropsy revealed a hard (bony), white mass (3.0 x 3.0 x 2.1 cm) on the left mandible. Microscopically, the mass consisted of islands or nests of epithelial and mesenchymal elements that formed abortive tooth structures. In other areas, tooth formation consisted of a pulp cavity lined by layers of odontoblasts, dentin, enamel, and ameloblasts. Concerning all features of normal tooth formation which was differentiated and mineralized yet completely disorganized, the diagnosis of complex odontoma was recommended.     

Genetic organisation of the capsule biosynthetic locus of Pasteurella multocida M1404 (B:2)

Capsules from a range of bacterial species have been shown to be major virulence determinants and capsule has been implicated in virulence in Pasteurella multocida. Moreover, capsular serogroup appears to be related to disease predilection. Haemorrhagic septicaemia strains belong to serogroup B and E, fowl cholera strains to serogroup A and atrophic rhinitis strains to serogroup D. The entire capsule biosynthetic locus of P. multocida A:1 has been cloned and its nucleotide sequence determined (Chung et al., 1998. FEMS Microbiol. Lett. 166, 289-296); however, nothing is known of the P. multocida B:2 capsule locus. In this work we have determined the nucleotide sequence and genetic organisation of the P. multocida M1404 (B:2) capsule locus. By analogy with the cap loci of other bacteria, the nucleotide sequence can be divided into three functional regions. Regions 1 and 3 comprise six genes involved in transport of the polysaccharide capsule to the cell surface. The deduced products of these genes show high similarity to proteins involved in capsule export in other bacteria. Region 2 comprises nine genes which are likely involved in biosynthesis of the polysaccharide capsule. The deduced products of three of these genes (bcbA, bcbB and bcbC) show significant similarity to proteins known to be involved in polysaccharide biosynthesis while the other six show no similarity to known proteins. However, their organisation indicates they are co-transcribed with bcbA, bcbB, bcbC and the Region 1 capsule export genes, suggesting strongly that they are also involved in capsule biosynthesis.     

Serological studies of Australian and Papua New Guinean cattle and Australian sheep for the presence of antibodies against bluetongue group viruses

Following isolation of a virus (CSIRO19) from insects in Australia and its identification as bluetongue virus serotype 20 (BTV20), a nationwide survey of antibodies in cattle and sheep sera was undertaken. Initial studies using the serum neutralization (SN) test showed that the distribution of BTV20 antibodies in cattle was confined to the northern part of Australia. Group-reactive antibody tests (agar gel diffusion precipitin, AGDP, and complement-fixation, CF) showed group-reactive cattle sera south of the BTV20 zone (northern Australia), and southwards from Queensland to New South Wales. Very few group-reactive sheep sera (45 out of 16213) were found and these were of doubtful epidemiological significance. Some of these BTV group-reactive, BTV20-negative, sera were tested in SN tests against BTV1 to 17 and Ibaraki (IBA) virus. The results indicated that BTV1, or a closely related orbivirus, was active in cattle in Queensland, northern Western Australia, and New South Wales, and that antibody to BTV15 was present in some of the cattle sera in northern Western Australia and the Northern Territory. Antibody to IBA virus was present in some cattle sera in Queensland, northern Western Australia and New South Wales. SN antibody titres ?60 were also found to a number of other BTV serotypes in cattle sera in northern Western Australia and Queensland (principally, BTV2 and BTV7). Low level reactions were commonly observed against these and a number of other BTV serotypes, often in the same serum samples. Further, 22% of the group-reactive cattle sera did not react with any of the viruses in the SN tests. Such results were difficult to interpret in terms of known Australian BTV or BTV-related isolates.     

Effect of biopesticides applied separately or together on nutritional indices of the rice leaffolderCnaphalocrocis medinalis

Laboratory assays were done to evaluate the effect of neem seed kernel extract (Azadirachta indica A. Juss),Vitex negundo L. (Lamiales: Verbenaceae) leaf extract, andBacillus thuringiensis (Berliner), applied separately or together, on nutritional indices of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). All three biopesticides suppressed feeding and larval growth and low concentrations affected the larval performance. The combined effect of the three biopesticides resulted in a considerable decrease in nutritional indices, indicating strong deterrence. Dose response relationships were established with respect to frass production and larval growth. The efficiency of conversion of ingested and digested food was considerably reduced.     

兽药生产企业在实施GMP中的常见问题分析

通过对兽药生产企业GMP的考察验收,发现兽药生产企业在实施GMP过程中存在着诸多共性问题.笔者汇总分析了企业在兽药GMP硬件、软件建设和验收准备中普遍存在的问题,对这些问题进行了讨论,以期使企业减少在实施GMP建设中的返工现象和不必要的损失,并做好兽药GMP检查验收的各项准备工作.