Relation of body fat distribution to hyperinsulinemia in children and adolescents: the Bogalusa Heart Study

The relation of body fat distribution to plasma levels of glucose and insulin during an oral glucose tolerance test was examined in 355 Black and White school-age children. Both central and peripheral fat were similarly related to fasting, 30-min, and 1-h glucose. Unlike peripheral fat, central body fat was more strongly related to the 1-h insulin response (r = 0.35 vs 0.26); this association remained significant for central fat independent of peripheral fat (r = 0.18). The strong relation of central fat to insulin response was noted in both races and sexes but not in either sexually immature or relatively thin children. These findings indicate that, even in early life, a central body fat pattern relates positively to insulin response to glucose load. Thus, knowledge of body fat localization may help identify persons most susceptible to hyperinsulinemia in early life.     

NMDA receptors regulate developmental gap junction uncoupling via CREB signaling

Signaling through gap junctions (electrical synapses) is important in the development of the mammalian central nervous system. Abundant between neurons during postnatal development, gap junction coupling subsequently decreases and remains low in the adult, confined to specific subsets of neurons. Here we report that developmental uncoupling of gap junctions in the rat hypothalamus in vivo and in vitro is associated with a decrease in connexin 36 (Cx36) protein expression. Both developmental gap junction uncoupling and Cx36 downregulation are prevented by the blockade of NMDA glutamate receptors, action potentials and the calcium-cyclic AMP response element binding protein (CREB), and are accelerated by CREB overexpression. Developmental gap junction uncoupling and Cx36 downregulation are not affected by blockade of non-NMDA glutamate receptors, and do not occur in hypothalamic neurons from NMDA receptor subunit 1 (NMDAR1) knockout mice. These results demonstrate that NMDA receptor activity contributes to the developmental uncoupling of gap junctions via CREB-dependent downregulation of Cx36.     

Effect of the external donors on the polymerization of 4-methyl-1-pentene with high activity MgCl2/TiCl4 catalytic system

In order to find out correlations between the structure of an external donor and the obtained polymer, the effects of different external donors on the activity and stereospecificity of the MgCl₂/TiCl₄ catalytic system in the bulk polymerization of 4-methyl-1-pentene (4MP) were carefully studied. Different silane compounds of the structure R_nSi(OR')_4-n (where: n = 1–3, R = alkyl/phenyl, R = alkyl) and Al(i-Bu)₃ (TIBA) were used as external donors and cocatalyst, respectively. The effect of the donor/TIBA mole ratio on the activity and stereospecificity of the catalytic system was studied. Some major effects were observed for the three different external donors, namely, Me₃Si(OMe), Me₂Si(OMe)₂, and Me₃Si(OBu)₃, in the 4MP polymerization process. It was observed that the effect of the external silane donor on the polymerization strongly depends upon the size of the alkoxy and hydrocarbon (alkyl/phenyl) groups which are attached to the silicon atom. A selective deactivation of the non-stereospecific centers, as well as a transformation of the non-stereospecific into isospecific centers, is assumed to occur. On the basis of the obtained results and literature data available for the propene polymerization, the concept of structural conformity between the ligand-surrounded active center and the monomer molecule was carried forward.     

Detection by PCR and isolation assays of the anaerobic intestinal spirochete Brachyspira aalborgi from the feces of captive nonhuman primates

The purpose of this study was to investigate the presence of the anaerobic intestinal spirochetes Brachyspira aalborgi and Brachyspira pilosicoli in the feces of captive nonhuman primates (n = 35) from 19 species housed at the Zoological Gardens, Perth, Western Australia. Both spirochete species are known to infect human beings. DNA was extracted from freshly collected feces with a commercially available QIAamp DNA stool minikit and subjected to PCR protocols amplifying portions of the 16S rRNA genes of the two spirochete species. The feces were also subjected to selective culture for the spirochetes. Subsequently, feces from 62 other captive animals or birds representing 39 species at the zoo were examined by PCR to determine whether they were reservoirs of infection. Six fecal samples from individuals from four primate species (two vervet monkeys, two Tonkean macaques, one Japanese macaque, and one hamadryas baboon) tested positive in the B. aalborgi PCR. B. aalborgi was not detected by PCR in any of the other animal or bird species tested, and B. pilosicoli was not detected in the primates or any of the other animals or birds. B. aalborgi was isolated from both PCR-positive vervet monkeys. This is the first time that B. aalborgi has been isolated from nonhuman primates and the first time that it has been isolated from the feces of any species.     

Parvovirus B19 replication in human umbilical cord blood cells.

The human parvovirus B19 is now known to be one of the causative agents of nonimmune hydrops fetalis and spontaneous abortions in pregnant women. The presence of the viral proteins and antibodies in fetuses of B19-infected women suggests that the virus can cross the placental barrier. In order to gain an insight into the mechanism of intrauterine fetal infection and the virus-induced hydrops fetalis, we examined whether human umbilical cord blood cells were permissive for B19 replication. Cord blood cells were infected with B19 in vitro, and Southern blot analyses of low M(r) DNA isolated from these cells revealed the presence of the characteristic replicative intermediates of B19 DNA. In addition, B19 genome expression in cord blood cells was detected by Northern blot analysis. Quantitative DNA dot blot analysis of culture supernatants documented complete assembly and release of B19 progeny virions in these cells. The progeny virions were biologically active in secondary infections of normal human bone marrow cells. The human umbilical cord blood cells may be a useful alternative to bone marrow and fetal liver culture systems for further studies on B19 since the need for bone marrow donors is obviated and, unlike fetal tissues, there are no ethical questions associated with the experimental use of cord blood because it is normally discarded. These studies also suggest that the umbilical cord blood may be a site for active replication of parvovirus B19 in vivo and may thus provide a means for transmission of the virus during intrauterine fetal infections.     

The effect of midazolam on median nerve somatosensory evoked potentials

Objective. To quantify the effect of an induction dose of midazolam on median nerve somatosensory evoked potentials.Methods. We studied 10 patients undergoing lumbar spine surgery. After an induction dose of intravenous midazolam was given, MNEPs were collected for ten minutes. After ten minutes the patients were intubated and their anesthetic was supplemented with 0.5% isoflurane, narcotic, and N₂O.Results. We found a clinically significant decrease in amplitude and an insignificant delay in latency.Conclusion. When midazolam is used as an anesthetic induction agent, a decrease in amplitude can be expected.     

Relationship between the existing caries status, plaque S. mutans and Cariostat caries activity test in children

An attempt was made in this study to find out the sensitivity and specificity of a caries activity test, CARIOSTAT and its relationship to the existing caries status and the plaque S. mutans level. The test proved to be highly sensitive and specific with significant relationship to the S.mutans count in the dental plaque. There also was a significant relationship between both the cultured microorganisms on MSB agar and the plaque in the Cariostat medium.     

Epitope insertion into variable loops of HIV-1 gp120 as a potential means to improve immunogenicity of viral envelope protein.

We report on the properties of a set of HIV-1 IIIB Env mutants carrying a linear gp41 epitope insertion (LLELDKWASL) in the V1, V2, V3 or V4 variable loop. Insertion of the epitope, which is defined by the HIV-1 neutralizing MAb 2F5, was well tolerated in the V1, V2 and V4 loops, as these mutants were properly expressed, retained reactivity to conformation-dependent monoclonal antibodies and exhibited patterns similar to the parental Env molecule. However, insertion of this epitope in the V3 loop was associated with drastically reduced protein expression. Relative to parental Env molecule, the V1, V2 and V4 insertion mutants demonstrated significantly increased binding to mAb 2F5 in vitro. To evaluate immunogenicity, mice and guinea pigs were immunized with plasmid expression vectors for the mutant proteins. For both mice and guinea pigs, all four mutants elicited anti-gp120 antibody responses. In mice the V1 and V3 insertion mutants, but neither the V2 or V4 insertion mutant nor the parental env, elicited significant titers against the epitope peptide, whereas in guinea pigs, V2 insertion mutant was most effective in eliciting anti-2F5 peptide antibody responses. While original V2 2F5 insertion mutant failed to elicit anti-2F5 peptide responses in mice, studies with 14 additional V2 insertion mutants revealed several insertion sites at which the epitope was able to induce epitope-specific antibody responses. This indicates that the precise position at which the epitope insertion takes place dictates the ability of the mutant to induce the epitope-specific antibody responses. When tested for virus neutralization activity, the guinea pig sera that contain high titers of anti-2F5 peptide antibody failed to enhance the virus neutralizing activity, suggesting that the configuration of 2F5 epitope plays a critical role in inducing neutralizing antibody responses. The results from this study may have potential implications with respect to modification of the HIV-1 Env molecule for the purpose of improving HIV-1 Env immunogenicity.