hMLH1 promoter methylation and lack of hMLH1 expression in sporadic gastric carcinomas with high-frequency microsatellite instability

The frog intermediate lobe consists of a single endocrine cell type, the melanotrope cells, which are under the tonic inhibitory control of dopamine. Separation of dispersed pars intermedia cells in a Percoll density gradient has revealed the existence of two melanotrope cell subpopulations, referred to as high-density (HD) and low-density (LD) cells. The aim of the present study was to investigate the effects of dopamine on each of these melanotrope cell subsets. Increasing doses of dopamine, ranging from 10(-9)-10(-6) M, inhibited the release of alpha-melanocyte-stimulating hormone (alpha-MSH) in LD (but not in HD) melanotrope cells. In addition, dopamine provoked a significant reduction of the rate of acetylation of alpha-MSH in LD cells but not in HD cells. Similarly, dopamine significantly decreased the accumulation of POMC messenger RNA in LD cells, whereas it did not affect POMC gene expression in the HD melanotrope subset. On the other hand, microfluorimetric studies revealed that dopamine induced a significant reduction of KCl-stimulated cytosolic free calcium concentration in both LD and HD cells. The present study provides additional evidence for functional heterogeneity of melanotrope cells in the frog pars intermedia. Because dopamine plays a pivotal role in the regulation of alpha-MSH secretion, these data suggest the involvement of cell heterogeneity in the physiological process of background color adaptation in amphibians.     

Experimental hepatobiliary fascioliasis in rabbits: a radiology-pathology correlation

RATIONALE AND OBJECTIVES: The authors sought to correlate the radiologic findings of hepatobiliary fascioliasis with pathologic features. METHODS: Serial ultrasound, computed tomography (CT), and magnetic resonance findings in seven rabbits with experimentally induced fascioliasis were obtained every other week. Direct cholangiogram was also obtained after the rabbits were killed. Radiology-pathology correlation was done in specimens. RESULTS: In the parenchymal phase (an acute phase of parenchymal invasion of a larva), CT showed subcapsular clustered areas of low attenuation. Magnetic resonance appearance was similar in shape but better than CT in characterizing the hemorrhagic nature of the lesion. Ultrasound findings were nonspecific in this phase. In the ductal phase (a stationary phase after residing in the bile duct), CT showed dilatation of central ducts with symmetric periportal hypoattenuation (periportal tracking). Magnetic resonance could not depict mild ductal dilatation. Ultrasound was most valuable in demonstrating the moving worm within the dilated duct. Pathologically, the hepatic parenchymal lesions consisted of a cluster of eosinophilic granulomas with hemorrhagic change (migratory tract of the flukes). Ductal changes were observed predominantly in the central bile ducts. Periportal lymphangiectasia was also noted. CONCLUSIONS: Computed tomography or magnetic resonance can demonstrate the characteristic evolutionary pattern of fascioliasis that reflects the unique life cycle of Fasciola hepatica. The role of ultrasound, although limited in the parenchymal phase, was most useful in the ductal phase in that it demonstrated the moving worms themselves.     

pH-dependent secondary conformation of bovine lens alpha-crystallin: ATR infrared spectroscopic study with second-derivative analysis

Of 37 Yersinia isolates from various aquatic environments, seven were Y. enterocolitica and 30 Y. intermedia. These isolates were biotyped, serotyped and tested for their susceptibility to 20 antibiotics. All Y. enterocolitica isolates were of biovar 1; those of Y. intermedia were distributed amongst four biovars (1, 2, 4 and 6). On the basis of combined biotyping and serotyping results, Y. enterocolitica isolates were distributed in five and Y. intermedia in 17 groups. With the exception of one Y. enterocolitica isolate which was resistant to tetracycline and streptomycin, the isolates were sensitive to the non-beta-lactam antibiotics. In contrast, various patterns of beta-lactam insensitivity were detected, including ampicillin and ticarcillin (35 isolates), cephalothin (33 isolates), carbenicillin (32 isolates), amoxycillin/clavulanate (23 isolates) and cefoxitin (22 isolates). No correlation between biotype or serotype and the susceptibility pattern of the isolates was apparent. Both inducible cephalosporinase activity against third-generation cephalosporins and inhibition of resistance to penicillins were detected in all Y. enterocolitica and Y. intermedia isolates by double-disk tests.     

Gonadal cell apoptosis: hormone-regulated cell demise

We have studied the release of nerve growth factor (NGF), a protein under consideration for treatment of Alzheimer's Disease, from polymer matrices and microspheres to characterize the stability of NGF, the dynamics of NGF release, and the distribution of NGF within the brain interstitium. Poly(ethylene-co-vinyl acetate) (EVAc) disks and poly(L-lactic acid) (PLA) microspheres were formed by codispersing NGF with one of a variety of molecules. The mass of mouse NGF (mNGF) detected following release from EVAc disks into buffered saline varied five-fold over the range of codispersants studied, with carboxymethyldextran providing optimal release, while the mass of recombinant human NGF (rhNGF) released varied four-fold from both EVAc disks and PLA microspheres, with albumin and carboxymethyldextran providing optimal release. Variation of the codispersant species significantly affected NGF release into buffered saline; it also had a noticeable, but small, effect of the amount of NGF found in the brain tissue following implantation of a polymer device. To improve NGF retention in tissue, NGF was conjugated to 70,000 molecular weight dextran and incorporated into a polymeric device. The distribution of NGF was enhanced by conjugation; comparison of NGF concentrations in the brain to a mathematical model of diffusion and elimination suggested that the elimination rate of NGF-dextran conjugate in the tissue was over seven times slower than the elimination rate of NGF. These results indicate that variation of the properties of the controlled release system may be useful in regulating the time course of NGF delivery to tissue, and that modification of the NGF itself can improve penetration and retention in the brain.     

Monoclonal antibody-based competitive ELISA for simultaneous detection of rinderpest virus and peste des petits ruminants virus antibodies

An experimental competitive enzyme-linked immunosorbent assay (morbillivirus cELISA) using a recombinant N antigen (rRPV N) expressed in a baculovirus and a ruminant morbillivirus (RPV and PPRV)-specific monoclonal antibody (P-13A9) was developed for simultaneous detection of rinderpest virus (RPV) and peste des petits ruminants virus (PPRV) antibodies and its diagnostic performance was evaluated. A set of known reference antisera against RPV and PPRV belonging to different lineages, experimental sera from cattle vaccinated for a RPV of Asian lineage, and field sera from cattle and sheep/goat populations known to be positive (West Africa) and negative (Korea) for RPV and PPRV were used for the evaluation. Morbillivirus cELISA results on the panel of experimental RPV and PPRV antisera showed high correlation (r=0.97) between the whole virus and the rRPV N antigens, suggesting that the rRPV N contains a ruminant morbillivirus-specific antigenic determinant recognized by the P-13A9 and it may be suitable as an ELISA antigen in place of the whole virus. Morbillivirus cELISA detected anti-RPV and anti-PPRV antibodies in all reference RPV and PPRV antisera containing VN titers >/=1:8, suggesting that the assay can simultaneously detect antibodies against RPV and PPRV. Anti-RPV antibody was detected by morbillivirus cELISA in vaccinated cattle as early as the VNT and continued to be detectable by both the cELISA and the VNT until termination of the study. When applied to field samples from Africa, morbillivirus cELISA showed good agreement with a RP cELISA kit (kappa value of 0.86) in bovine sera and with a peste des petits ruminant cELISA kit (kappa value of 0.81) in caprine/ovine sera. Usefulness of morbillivirus cELISA using the rRPV N protein was discussed.