Carbohydrate metabolism in intact golden hamsters infected with plerocercoids of Spirometra erinacei (Cestoda: Diphyllobothriidae)

This study was performed to investigate the mechanism involved in a decrease in the serum glucose of golden hamsters infected with plerocercoids of Spirometra erinacei. The concentration of glucagon, the activity of glucose-6-phosphatase in the liver, and the in vivo incorporation of 2-deoxyd-[1,2-³H]glucose into various organs increased in plerocercoid-infected hamsters compared with controls. Furthermore, the serum from the plerocercoid-infected hamsters enhanced the in vitro incorporation of [U-¹⁴C]glucose into adipose tissues, compared with control serum. The serum levels of immunoreactive insulin and somatomedin associated with nonsuppressible insulin-like activity in experimental animals, however, were not significantly different from those in controls. Therefore, we conclude that the decrease in serum glucose associated with plerocercoid infection is not the result of a decrease in gluconeogenesis, but the result of an increased utilization of glucose in the peripheral tissues.     

Evidence of the growth factor in mouse serum infected withSpirometra erinacei plerocercoids

To investigate the action of the growth factor secreted bySpirometra erinacei plerocercoids, various organ weights, body weight and head-body length were measured in Snell normal and dwarf mice after injection with the serum from mice and rats. Serum from mice infected with the plerocercoids caused significant increases in the weights of the liver and spleen, in the same manner as mice infected with the plerocercoids. However, serum from rats infected with plerocercoids did not cause significant changes in these parameters. The growth factor in the serum of mice infected with plerocercoids was stable at –20°C for at least 6 months and easily passed through the peritoneum.     

Endolymphatic perfusion with EGTA-acetoxymethyl ester inhibits asphyxia- and furosemide-induced decrease in endocochlear potential in guinea pigs

We examined the effect of the Ca(2+) concentration in the endolymph ([Ca](e)) or in the endolymphatic surface cells ([Ca](i)) on the endocochlear potential (EP) by using an endolymphatic or perilymphatic perfusion technique, respectively. (i) A large increase in [Ca](e) up to approximately 10(-3) M with a fall in the EP was induced by transient asphyxia ( approximately 2 min) or by the intravenous administration of furosemide (60 mg/kg), and a significant correlation was obtained between the EP and p[Ca](e) (= -log [Ca](e), r = 0.998). (ii) Perfusion of the endolymph with 10 mM EGTA for 5 min neither produced any significant change in the EP nor altered the asphyxia-induced change in EP (DeltaEP(asp)), suggesting that neither [Ca](e) nor the Ca(2+) concentration gradient across the stria vascularis contributed directly to the generation of the EP in the condition of low [Ca](e). In contrast, endolymphatic perfusion with high Ca(2+) (more than 10 mM) produced a decrease in EP and a significant correlation was obtained between the EP and the Ca(2+) concentration of perfusion solution (r = 0.982), suggesting that Ca(2+) permeability may exist across the stria vascularis. (iii) The administration of a Ca(2+) chelator, EGTA-acetoxymethyl ester (AM, 0.3 mM), to the endolymph, which produced a gradual increase in EP, suppressed significantly, by 60-80%, DeltaEP(asp) or furosemide-induced changes in EP. In contrast, perilymphatic administration of 0.5 mM EGTA-AM caused no significant suppression of the DeltaEP(asp). These findings suggest that [Ca](i) plays an important role in generating/maintaining a large positive EP.     

Two antigens on zygotes and ookinetes of Plasmodium yoelii and Plasmodium berghei that are distinct targets of transmission-blocking immunity.

We have developed transmission-blocking monoclonal antibodies (MAbs) against Plasmodium yoelii 21-kDa (Pys21) and 28-kDa (Pys25) ookinete surface proteins. These MAbs block infectivity of P. yoelii to Anopheles stephensi. One MAb, 14, cross-reacted by Western blotting with a 28-kDa surface protein (Pbs25) of P. berghei ookinetes and blocked oocyst development, as assayed by direct mosquito feeds on passively immunized P. berghei-infected mice. In total, we have identified two ookinete surface proteins in P. yoelii, one of which is also present in P. berghei. The transmission-blocking activity of the anti-Pys25 MAb 4 was complete and more potent than that of the anti-Pys21 MAb 2. Moreover, Fab fragments of MAb 4 had transmission-blocking activity in mice. In comparison, Fab fragments of MAb 2 did not have detectable transmission-blocking effect, although F(ab')2 did. Furthermore, MAb 2 and MAb 4 appeared to block the in vitro formation and development of zygotes as well.     

Studies on elementary reactions in the polymerization of 1,2-epoxycyclohexane with organozinc compounds as initiators

1,2-Epoxycyclohexane ( 1 ) was found to behave differently from propylene oxide (PO) in polymerization reactions with organozinc compounds as initiators. A chair-type complex, [Zn-MP]_2,2, is the only compound that shows high catalytic activity for both polymerization of 1 and PO, following an anionic coordination mechanism. On the other hand, the polymerization of 1 with ZnEt₂ or (EtZnOMe)₄ as initiator proceeds according to a cationic mechanism. Cationic polymerization of 1 with ZnEt₂ has two modes of termination reaction resulting in the formation of terminal units containing vinyl ether and allyl ether moieties. The initiation and propagation mechanism of 1 by [Zn-MP]_2;2 is similar to that of PO, but chain transfer reaction takes place in the polymerization of 1 owing to the low stability of the growing chain end. By using [Zn-MP]_2,2 as initiator, it was possible to prepare a block copolymer consisting of an isotactic sequence of monomeric units of PO and a syndiotactic sequence of monomeric units of 1 .     

Liver cell membrane antibody detected by protein A and isolated rabbit liver plasma membrane in sera of patients with chronic liver diseases

Using the plasma membrane fraction isolated from rabbit liver (RLPM), we detected non-species specific IgG antibody against liver cell surface membrane in the sera from the patients with chronic liver diseases. The sea were treated with dithiothreitol and iodoacetamide, and absorbed with sufficient amount of actin isolated from rabbit striated muscles. The antibody was detected by incubation of RLPM with the treated and absorbed sera and subsequent determination of IgG bound to RLPM by 125I-staphylococcal protein A. It was found mainly in the patients with autoimmune hepatitis (12 of 28) and liver cirrhosis (eight of 24). It occurred more frequently in HBsAg negative liver cirrhosis than in HBsAg positive forms (six of 13 vs two of 11). The frequency of the antibody was low in chronic hepatitis except autoimmune hepatitis, and primary biliary cirrhosis. Thus the antibody against RLPM was an immunological marker of autoimmune hepatitis and HBsAg negative liver cirrhosis. The occurrence did not correlate with those of anti-smooth muscle antibody, anti-nuclear antibody and anti-mitochondrial antibody. In two cases of autoimmune hepatitis, the antibody against RLPM decreased with clinical improvement induced by corticosteroids.     

Effects of fluoride release from bis-GMA/TEGDMA resin regulated by gamma-methacryloxypropyltrimethoxysilane on demineralization of bovine enamel

We previously demonstrated that fluoride release from resins could be regulated by the polysiloxane coating of the fluoride additives. The present study investigated the effects of regulated fluoride release from resin on enamel demineralization in vitro. Bovine enamel cavities were restored with bis-GMA/TEGDMA resins containing 50 wt% NaF powders treated with or without gamma-methacryloxypropyltrimethoxysilane. Specimens were immersed in distilled water that was changed daily to measure the amount of fluoride released over 40 days, and thereafter subjected to pH-cycling. Microradiographic observations were performed to determine total mineral loss (AZ) and lesion depth (Ld) on the enamel. In addition, fluorine distribution was analyzed using EPMA. The resin containing untreated NaF exhibited high-rate and short-term fluoride release, whereas the resin containing treated NaF released low concentrations of fluoride over a longer period. The former showed high fluorine uptake in the adjacent enamel. In contrast, the latter showed high fluorine uptake not only in the adjacent enamel, but also in a wider area of enamel surface. The latter also showed lower AZ and Ld values in the surrounding enamel, indicating a high inhibitory effect on caries formation. Therefore, it is suggested that regulated fluoride release from the resin based on polysiloxane coating is effective in preventing caries formation.     

Studies on the osmophilic fungus Wallemia sebi as an allergen evaluated by skin prick test and radioallergosorbent test

Recently, Wallemia sebi, a species of osmophilic fungi, has been abundantly detected in house dust using low water activity media. In this study, allergenic activity of W. sebi was assessed by skin prick test and radioallergosorbent test (RAST) in 74 asthmatic patients ranging from 6 to 32 years of age. Aspergillus fumigatus and house dust were used for comparison. In skin prick test, W. sebi extract, A. fumigatus extract and house dust extract elicited positive reactions in 4 (5.4%), 4 (5.4%) and 51 (68.9%) patients, respectively. RAST showed positive results in 14 subjects (18.9%) for W. sebi extract, in 8 (10.8%) for A. fumigatus extract and in 59 (79.7%) for house dust extract. These results indicated that some asthmatic individuals showed immediate-type hypersensitivity to W. sebi, and which means this fungal species may be of importance to atopic diseases as a causative agent.     

Association of microneme antigens of Plasmodium brasilianum merozoites with knobs and other parasite-induced structures in host erythrocytes.

The localization of Plasmodium brasilianum antigens, common to merozoite micronemes and parasite-induced structures in the host erythrocyte, was determined by means of immunogold electron microscopy and monoclonal antibodies directed against blood stages of this parasite. All monoclonal antibodies reacted with micronemes. In addition, some reacted with either knob protrusions or caveolae of the host erythrocyte membrane; one reacted with a parasite-derived antigen present in the erythrocyte cytoplasm. Gold particles appeared over the membranes of ring-infected cells before the appearance of knobs and caveolae. We hypothesize that at least some knob- and caveolae-associated antigens of P. brasilianum are inserted into the erythrocyte membrane at the time of merozoite invasion.