[An alpha-1-antitrypsin deficiency allele PI*Siiyama found in a disputed paternity case]

An incompatible mother-child pair was found in an alpha-1-antitrypsin (PI) system in a disputed paternity case. By the isoelectric focusing, the PI type of the mother and the child were confirmed PI M1 and PI M2, respectively. Testing of many other genetic markers could not exclude her motherhood. Therefore, the mother and the child were inferred to be heterozygous carriers of a PI deficiency allele. PCR-SSCP analysis of exon 2 suggested that the PI types of the mother and the child are heterozygous M1-Siiyama and M2-Siiyama, respectively.

Tumor necrosis factor-alpha induces substance P in sympathetic ganglia through sequential induction of interleukin-1 and leukemia inhibitory factor

The present study establishes that tumor necrosis factor-alpha (TNF-alpha) induction of sympathetic substance P (SP) requires sequential induction of both interleukin (IL-1) and leukemia inhibitory factor (LIF). TNF-alpha dose-dependently induces SP, an induction that is secondary to an increase in the SP precursor, preprotachykinin (PPT), mRNA. Since TNF-alpha conditioned medium (CM) mimics the effect of TNF-alpha by raising SP, actions that are not antagonized by a neutralizing TNF-alpha antibody, TNF-alpha induction of SP is mediated by a soluble intermediate or intermediates. The blockade of TNF-alpha action by a specific IL-1 receptor antagonist and the induction of IL-1 mRNA by TNF-alpha suggest that IL-1 is one of the intermediates. Moreover, because immunoprecipitation with LIF antibodies decreases SP-inducing activity of TNF-alpha CM, and because LIF mRNA is also induced by TNF-alpha, LIF is a second intermediate. Furthermore, TNF-alpha-induced LIF mRNA is blocked by the IL-1 receptor antagonist, whereas IL-1-induced LIF mRNA is not affected by TNF-alpha antibodies, suggesting that TNF-alpha first induces IL-1, and IL-1 subsequently induces LIF. These data suggest that TNF-alpha induces SP in sympathetic ganglia through the sequential inductions of IL-1 and LIF.

Fibroblast growth factor 2 increases Otx2 expression in precursor cells from mammalian telencephalon

Dissociated primary cultures from rat telencephalon at different developmental stages were used to study the effect of basic fibroblast growth factor (FGF2) on Otx2, Dlx1, and Emx1, three homeobox genes expressed in different regions of the developing mammalian forebrain. At embryonic day (E)13.5. the regional pattern of expression of Otx1, Otx2, Dlx1, Dlx2, Dlx5, and Emx1 is maintained in primary culture, suggesting that cells are already committed to a regional identity at this stage. In these cultures, Otx2 is expressed by precursor cells, whereas Dlx1 and Emx1 are predominantly expressed by postmitotic cells. We found that FGF2 increased Otx2 expression within precursor cells and the total number of Otx2-expressing cells. This effect was gene-specific, dose-dependent, and temporally regulated, with larger effects at earlier stages of development (E11.5). At E13.5, the effect of FGF2 on Otx2 expression was restricted to the basal telencephalon. Our results suggest that a restricted population of neuroblasts respond to FGF2 in a temporally regulated fashion by proliferating and increasing Otx2 expression. This interaction between FGF2 and Otx2 may be important for the regulation of neurogenesis in the forebrain.

Evaluation of a dynamical model of speech perception

Previous work (Tuller, Case, Ding, & Kelso, 1994) has revealed signature properties of nonlinear dynamical systems in how people categorize speech sounds. The data were modeled by using a two-well potential function that deformed with stimulus properties and was sensitive to context. Here we evaluate one prediction of the model--namely, that the rate of change of the potential's slope should increase when the category is repeatedly perceived. Judged goodness of category membership was used as an index of the slope of the potential. Stimuli from a "say"-"stay" continuum were presented with gap duration changing sequentially throughout the range from 0 to 76 to 0 msec, or from 76 to 0 to 76 msec. Subjects identified each token as either "say" or "stay" and rated how good an exemplar it was of the identified category. As predicted, the same physical stimulus presented at the end of a sequence was judged a better exemplar of the category than was the identical stimulus presented at the beginning of the sequence. In contrast, stimuli presented twice near the middle of a sequence with few (or no) stimuli between them, as well as stimuli presented with an intervening random set, showed no such differences. These results confirm the hypothesis of a context-sensitive dynamical representation underlying speech.

[The infection of hepatitis D virus in adult tupaia]

A new animal model of HDV/HBV infection in adult tupaia (tree shrews) was established to study its pathogenesis and treatment of hepatitis D. In 20 artificially fed adult tupaiae, the positive rate of serum HBsAg was 75% (15/20) after inoculation of human HBV DNA positive serum. After inoculation with positive human serum HBV DNA and positive HDV RNA by way of coinfection and superinfection, serum HBsAg, HDAg and anti-HD were positive one after another in 8 out of 13 tupaiae of the coinfection group and in 6 out of 9 tupaiae of the superinfection group. In some of them HDV RNA was positive in serum or in liver tissue. Transmission of HDV/HBV infection among tupaiae was successful. In group I, animals were inoculated with human HDV/HBV positive serum. In Group II and III, animals were inoculated with tupaia HDV/HBV positive serum of the Group I and II respectively. Serum HBsAg, HDAg and anti-HD became positive one after another in 3 out of 4 tupaiae of the Group II and 4 out 5 tupaiae of the group III. In 2 animals of the Group III, serum HDV RNA was positive and HBsAg and HDAg were detected in the liver tissue. Serum HBsAg was persistantly positive for 16-19 months in the superinfection group. In 2 of them, serum HDAg and anti-HD were alternatively positive and in one of them serum anti-HD was positive persistantly indicating that HDV infection may persist and transform into chronic HDV infection. In the HDV infected tupaiae, there were elevated serum ALT and hepatitis-like pathological changes in the liver tissue which were similar to those in the chimpanzee. We conclude that tupaia may be used as an experimental model of hepatitis D.

High levels of anti-human immunodeficiency virus type 1 (HIV-1) memory cytotoxic T-lymphocyte activity and low viral load are associated with lack of disease in HIV-1-infected long-term nonprogressors

Lack of disease in long-term nonprogressors with human immunodeficiency virus type 1 (HIV-1) infection was strongly associated with very low copy numbers of HIV-1 DNA and RNA in peripheral blood mononuclear cells and plasma and the presence of high levels of anti-HIV-1 CD8+ memory cytotoxic T lymphocytes specific for Gag, Pol, and Env, compared with levels present in intermediate and advanced progressors. CD8+ memory cytotoxic T lymphocytes may have an important role in controlling HIV-1 replication and preventing disease in long-term nonprogressors.

Intermittent aortic crossclamping prevents cumulative adenosine triphosphate depletion, ventricular fibrillation, and dysfunction (stunning): is it preconditioning?

This study was designed to determine whether intermittent warm aortic crossclamping induces cumulative myocardial stunning or if the myocardium becomes preconditioned after the first episode of ischemia in canine models in vivo. The role of adenosine triphosphate catabolism and subsequent release of purines on reperfusion-mediated postischemic ventricular dysfunction and arrhythmias was assessed with the use of selective inhibitors of nucleoside transport, p-nitrobenzylthioinosine (NBMPR), and a specific adenosine deaminase inhibitor, erythro-9-[2-hydroxy-3-nonyl] adenine (EHNA). Thirty-two anesthetized dogs were instrumented to monitor left ventricular contractility, off bypass, by sonomicrometry. During cardiopulmonary bypass dogs were treated before ischemia with either saline solution (control group, n = 8) or EHNA (100 mumol/L) and NBMPR (25 mumol/L) (EHNA/NBMPR group, n = 8). Hearts were subjected to either 60 minutes of global ischemia and 120 minutes of reperfusion (n = 16) or 6 episodes of 10 minutes of global ischemia and 10 minutes of reperfusion, followed by 60 minutes of reperfusion (n = 16). Sixty minutes of sustained ischemia resulted in 80% loss of adenosine triphosphate and induced reperfusion-mediated ventricular fibrillation and severe left ventricular dysfunction in the control group. EHNA/NBMPR treatment augmented myocardial adenosine trapping during ischemia, attenuated ventricular fibrillation, and enhanced left ventricular functional recovery, despite similar depletion of adenosine triphosphate (80% loss). In the intermittent ischemia experiment, the first episode of 10 minutes of ischemia and reperfusion caused significant adenosine triphosphate depletion, ventricular fibrillation, and left ventricular stunning in both control and drug-treated groups. The prevalence of ventricular fibrillation was greater in the control group than in the drug-treated group after the first episode of ischemia (p < 0.05). Adenosine was the major nucleoside accumulated in the myocardium at the end of 10 minutes of ischemia in the EHNA/NBMPR-treated group (p < 0.05 versus control). Subsequent episodes of ischemia prevented ventricular fibrillation and did not cause cumulative left ventricular stunning in either group. Left ventricular function fully recovered in the EHNA/NBMPR-treated group after intermittent ischemia, but remained stunned in the control group. Unlike sustained ischemia, intermittent ischemia and reperfusion preserved myocardial adenosine triphosphate, limited purine release, and prevented ventricular fibrillation and cumulative stunning. These results suggest that intermittent ischemia and reperfusion augmented the endogenous protective mechanism or mechanisms of "preconditioning." Nucleoside trapping improved functional recovery after sustained or repetitive ischemia. It is concluded that adenosine triphosphate preservation or blockade of nucleoside transport may play an important role in the activation of endogenous myocardial protective mechanisms that "precondition" against subsequent ischemic stress.

Copresence of prostaglandin EP2 and EP3 receptors on gastric enterochromaffin-like cell carcinoid in African rodents

BACKGROUND & AIMS

Prostaglandins (PGs) have important roles in the regulation of gastric acid secretion. The aim of this study was to examine the possible presence of PG receptors on the gastric enterochromaffin-like (ECL) carcinoid of Mastomys natalensis, which might be a useful model of normal ECL cells.

METHODS

A [3H]PGE2 binding experiment was performed by using the ECL tumor membrane, and intracellular signal transduction was studied in the cells. In addition, Northern blot analysis using EP2 and EP3 receptor complementary DNAs was conducted.

RESULTS

[3H]PGE2 specifically bound to the tumor cell membrane, and the binding was displaced by various PGs with a potency order of PGE1 = PGE2 > enprostil > PGF2 alpha. Although PGE1 and PGE2 stimulated 5'-cyclic adenosine monophosphate (cAMP) production, neither PGF2 alpha nor enprostil had any effect. On the other hand, all of PGE1, PGE2, PGF2 alpha, and enprostil attenuated the forskolin-induced cAMP production. Moreover, enprostil inhibited histamine release induced by forskolin. However, on pertussis toxin treatment, PGE2 paradoxically enhanced the forskolin-induced increase of cAMP production. Finally, the presence of EP2 and EP3 receptor messenger RNAs was confirmed by RNA blot analysis.

CONCLUSIONS

The ECL carcinoid tumor cells of Mastomys seem to possess two subtypes of PGE receptor: EP2 linked to cAMP production and EP3 coupled with inhibitory guanosine 5'-triphosphate-binding proteins mediating the inhibition of cAMP production.

[The distribution of SbV nonstructural protein 2 (nsP2) in host cell]

The distribution of SbV nsP2 has been observed by means of immunolabelling electron microscopy. The results showed that SbV nsP2 existed both in the cytoplasm and in the nucleus of host cell. When the cDNA of SbV nsP2 was transfected in host cell, the nsP2 also accumulates in the nucleus.

[The preliminary study of insulin resistance in pregnancy induced hypertension]

OBJECTIVE

To observe the changes of glucose metabolism in late pregnancy and to reveal the relationship between insulin resistance and pregnancy induced hypertension (PIH).

METHODS

The 75g oral glucose tolerance test (OGTT) was performed in 30 cases with PIH (37-41 weeks gestation), 30 cases of normal pregnancy and 12 non-pregnant women. The levels of serum glucose, insulin and C-peptide were measured by radioimmunoassay, and the areas under the curve (AUC) were calculated.

RESULTS

There were significant increases of the peak level or AUC of insulin in PIH (61.42 +/- 48.72, 137.12 +/- 81.12 mIU/L) and in normal pregnant group (70.46 +/- 58.42, 150.37 +/- 104.76 mIU/L) compared with non-pregnant controls (17.12 +/- 11.03, 34.38 +/- 16.01 mIU/L) (P < 0.01), however, they had a similar glucose levels before or after GTT (P > 0.05). Furthermore, there was no correlationship between systolic or diastolic blood pressure and the fasting insulin or the AUC.

CONCLUSIONS

Insulin resistance and hyperinsulinemia were found in late pregnancy, but the changes of insulin resistance in PIH cases was not significant. So, there was no definitive relationship between insulin resistance and the rising of blood bressure of PIH.

Quantitation of human immunodeficiency virus type 1 DNA and RNA by a novel internally controlled PCR assay

A novel internally controlled PCR (ICPCR) assay was developed to accurately quantitate human immunodeficiency virus type 1 (HIV-1) DNA and RNA in peripheral blood mononuclear cells and plasma. The ICPCR assay was sensitive and reproducible within a linear range of amplification of 10(0) to 10(3) copies for HIV-1 DNA and 10(1) to 10(4) copies for HIV-1 RNA. The assay detected HIV-1 RNA in plasma and peripheral blood mononuclear cells from all HIV-1 subjects regardless of disease stage. ICPCR was compared with a branched-DNA signal amplification assay for subjects beginning antiretroviral therapy. The reductions in plasma HIV-1 RNA in response to therapy were comparable with the two assays. The ICPCR assay should be useful in monitoring HIV-1 RNA levels both in natural history studies and in clinical trials of antiretroviral agents.

Molecular basis of inter-alpha-trypsin inhibitor heavy chain H1 (ITIH1) polymorphism

A genetic polymorphism of the inter-alpha-trypsin inhibitor heavy chain H1 (ITIH1) was analyzed at the nucleic acid level. Three common alleles, ITIH1*1, ITIH1*2 and ITIH1*3, were characterized by mutations at codons 551 and 561 in exon 14. ITIH1*1 was characterized by GAG (Glu) at codon 551 and CAG (Gln) at codon 561, ITIH1*2, by GTG (Val) and CGG (Arg), and ITIH1*3, by GAG (Glu) and CGG (Arg).

The microtubule cytoskeleton in human phagocytic leukocytes is a highly dynamic structure

The microtubule cytoskeleton of human leukocytes has been difficult to study, in part, due to the lack of a reliable protocol for the indirect immunofluorescence staining of microtubules in these cells. We report here the development of a simple and reliable immunocytochemical labeling protocol for the examination of microtubules in leukocytes including monocytes, neutrophils, and eosinophils. The dynamic properties of microtubules in both monocytes and neutrophils were examined by indirect immunofluorescence staining of cells following exposure to nocodazole. Nocodazole-induced depolymerization is extremely rapid in both cell types, as is the regrowth of microtubules following removal of the nocodazole. Rapid reorganization of the microtubule cytoskeleton was also observed in neutrophils undergoing chemotactic stimulation. Bundling of microtubules was observed in both monocytes and neutrophils isolated from patients undergoing taxol infusion chemotherapy. The taxol-induced bundles were transient in nature as they were absent from samples collected 48 h following the completion of the taxol infusion. These results demonstrate the unique dynamic properties of leukocyte microtubules and indicate that they can be altered in vivo. The development of this staining protocol should allow for the further analysis of leukocyte microtubules as related to the normal functional response of these cells and form the basis for correlating alterations in microtubule dynamics with the effects of taxol on leukocyte function.

Binding of TFIID to the CYC1 TATA boxes in yeast occurs independently of upstream activating sequences

Functional transcription initiation complexes can be assembled in vitro without the aid of regulatory factors that bind to upstream activating sequences. However, promoters that lack upstream activating sequences are transcribed poorly if at all in vivo, suggesting that regulatory factors are necessary for the assembly of transcription initiation complexes in cells. To test this possibility, we asked whether the general transcription factor TFIID can bind to a promoter in yeast that lacks upstream activating sequences and is transcriptionally inactive. Analysis of an inactive CYC1 core promoter by high-resolution genomic footprinting revealed efficient binding of TFIID to either of two TATA box elements. Addition of a heat shock element rendered this promoter highly responsive to induction of transcription by heat shock but did not alter the TATA box footprints in the core promoter. Inactivation of all but one TATA box by site-directed mutagenesis did not prevent TFIID from binding to the remaining wild-type TATA box independently of regulatory sequences. These results indicate that upstream regulatory factors are not required for the in vivo binding of TFIID to the CYC1 promoter and that binding of TFIID to DNA is not necessarily a rate-limiting step in the activation of transcription in cells. Differences in chromatin structure may account for why regulatory transcription factors are required for the binding of TFIID to some promoters but not to others.

Reaction of Cr(VI) with ascorbate and hydrogen peroxide generates hydroxyl radicals and causes DNA damage: role of a Cr(IV)-mediated Fenton-like reaction

Incubation of Cr(VI) with ascorbate generated Cr(V), Cr(IV) and ascorbate-derived carbon-centered alkyl radicals, as well as formyl radicals. H2O2 caused generation of hydroxyl radicals (OH) and much higher levels of Cr(V), showing that .OH can be generated via a Cr(IV)-mediated Fenton-like reaction (Cr(IV) + H2O2-->Cr(V) + .OH + OH-). 1,10-Phenanthroline and deferoxamine inhibited the formation of both .OH and Cr(V) from the reaction of Cr(VI) with ascorbate in the presence of H2O2. Electrophoretic assays showed that ascorbate-derived free radicals caused DNA double-strand breaks. .OH radicals generated by Cr(V)- and Cr(IV)-mediated Fenton-like reactions also caused DNA double-strand breaks. HPLC measurements showed that .OH radicals generated by Cr(IV) and Cr(V) from H2O2 caused 2'-deoxyguanine hydroxylation to form 8-hydroxy-2'-deoxyguanine.

[The effect of Sindbis virus multiplication on gene expression of host cells]

Sindbis virus (SBV) infection mediated a rapid shutoff of host cellular gene expression (mRNA synthesis and protein synthesis); however the synthesis of cellular rRNA remained at the same level as the uninfected cells. Meanwhile a cellular protein P105 was shown to be enriched in the nuclear matrix. Actionmycin D treatment after virus infection resulted in an apparent reduce in the production of viral structural proteins and infectious virions. The results presented here not only demonstrated the complexity of SBV-mediated regulation of host gene expression, but also suggested SBV nonstructural protein nsP2 and capsid protein C were possibly involved in this process.

Early gene changes in myocardial ischemia

After certain periods of myocardial ischemia and reperfusion, cardiac dysfunction exists in the absence of myonecrosis. In a blood-perfused isolated rat heart model, we have demonstrated early gene changes that are associated with global myocardial "stunning." Early gene changes included elevations in the expression of messenger RNAs for HSP70, c-myc and c-fos. Increased expression of messenger RNAs for protooncogenes is an important observation because of the role of protooncogenes as nuclear transcription factors. From these study findings, it would appear that the stunning state is associated with early gene changes that may signal the induction of a hypertrophic process. Subsequent studies are required to demonstrate the exact events which take place in the course of stunning that directly initiate an alteration in gene expression.

The interleukin-1-induced increase of substance P in sympathetic ganglia is not mediated by ciliary neurotrophic factor

Interleukin-1 (IL-1) induction of substance P (SP) in cultured sympathetic ganglia requires a soluble intermediate molecule that is present in IL-1 conditioned medium (IL-1CM). One of the required intermediates is leukemia inhibitory factor (LIF; Shadiack et al., J Neurosci 13:2601-2609, 1993). In the present study we have examined the possibility that ciliary neurotrophic factor (CNTF) is another intermediate involved in the IL-1 induction of sympathetic SP. CNTF mimics the action of IL-1CM by raising both SP and choline acetyltransferase activity--actions that are blocked by a specific neutralizing antiserum for CNTF. However, IL-1CM and CNTF differ in their response to depolarizing agents: while KCl (40 mM) blocks the action of IL-1CM (and LIF), it enhances the action of CNTF. Furthermore, neither CNTF bioactivity nor CNTF protein is detected in IL-1CM. Neutralizing antiserum to CNTF fails to block the action of either IL-1 or IL-1CM, suggesting that neither a soluble nor a membrane-bound form of the molecule is active in direct response to IL-1 action. While Northern blots confirm the presence of both CNTF and CNTF receptor mRNA in neonatal ganglia, neither culturing nor IL-1 treatment alters these mRNA levels. These data taken together suggest that while CNTF is present and possibly active in sympathetic ganglia, it is not a mediator of the IL-1 induction of SP.

One-electron reduction of vanadate by ascorbate and related free radical generation at physiological pH

The one-electron reduction of vanadate (vanadium(V)) by ascorbate and related free radical generation at physiological pH was investigated by ESR and ESR spin trapping. The spin trap used was 5,5-dimethyl-1-pyrroline N-oxide (DMPO). Incubation of vanadium(V) with ascorbate generated significant amounts of vanadium(IV) in phosphate buffer (pH 7.4) but not in sodium cacodylate buffer (pH 7.4) nor in water. The vanadium(IV) yield increased with increasing ascorbate concentration, reaching a maximum at a vanadium(V): ascorbate ratio of 2:1. Addition of formate to the incubation mixture containing vanadium(V), ascorbate, and phosphate generated carboxylate radical (.COO-), indicating the formation of reactive species in the vanadium(V) reduction mechanism. In the presence of H2O2 a mixture of vanadium(V), ascorbate, and phosphate buffer generated hydroxyl radical (.OH) via a Fenton-like reaction (vanadium(IV)+H2O2-->vanadium(V)+.OH+OH-). The .OH yield was favored at relatively low ascorbate concentrations. Omission of phosphate sharply reduced the .OH yield. The vanadium(IV) generated by ascorbate reduction of vanadium(V) in the presence of phosphate was also capable of generating lipid hydroperoxide-derived free radicals from cumene hydroperoxide, a model lipid hydroperoxide. Because of the ubiquitous presence of ascorbate in cellular system at relatively high concentrations, one-electron reduction of vanadium(V) by ascorbate together with phosphate may represent an important vanadium(V) reduction pathway in vivo. The resulting reactive species generated by vanadium(IV) from H2O2 and lipid hydroperoxide via a Fenton-like reaction may play a significant role in the mechanism of vanadium(V)-induced cellular injury.

Cloning and analysis of MAGE-1-related genes

The spectrum of MAGE gene expression in the human melanoma cell line DM150 was examined using reverse transcription polymerase chain reaction and cDNA cloning. We have isolated five full-length cDNAs from DM150 which were identified as MAGE-1, MAGE-3, MAGE-12 and two previously undescribed MAGE genes, MAGE-3b and MAGE-X2. DNA sequence analysis of the coding regions of the MAGE-3b and MAGE-X2 genes revealed 83% and 88% identity with MAGE-1, while MAGE-3b was 98% homologous with the full length MAGE-3 clone. The predicted amino acid sequences of MAGE-X2 and MAGE-3b contain consensus HLA-A1 peptide binding motifs, suggesting that, like MAGE-1, they may code for tumor-associated antigens. In addition, a nonamer peptide encoded by both the MAGE-3 and MAGE-12 genes was shown by direct binding studies to contain an aggretope for HLA-A2.

Association of rotating shiftwork with preterm births and low birth weight among never smoking women textile workers in China

1035 married women workers in three modern textile mills in Anhui, China were surveyed to investigate the association of rotating shiftwork with low birth weight and preterm birth in 1992. Information on reproductive health, occupational exposure history, and other covariates including age at pregnancy, time and duration of leave from job since pregnancy, and mill location was obtained by trained nurses with a standardised questionnaire. This analysis was limited to 845 women (887 live births), who were middle or high school graduates, never smokers, and non-alcohol drinkers. About 72% of the women worked an eight day cycle with shift changes every two days throughout pregnancy. Mean gestational age was 38.8 and 39.0 weeks for shift and regular schedule workers, respectively. Multiple linear regression was used to adjust for confounding factors including maternal age at pregnancy, order of live birth, mill location, job title, occupational exposure to dust/gases/fumes, stress, carrying and lifting of heavy loads, working in a squat position, time and duration of leave from the job since pregnancy, and indoor coal combustion for heating. The adjusted difference in gestational age associated with rotating shifts was statistically significant (beta = -0.44 (SE 0.20) weeks.) Mean birth weights were 3248 g and 3338 g for rotating shift workers and regular schedule workers respectively. The estimated effect of rotating shiftwork on birth weight was -79 (SE 42) g. When the analysis was restricted to first order live births or to production workers, the estimated effects of rotating shiftwork on both gestational age and birth weight were significant. The proportions of preterm birth (<37 weeks) and low birth weight (<2500 g), respectively, were 20% and 9% for shift workers and 15% and 6% for regular schedule workers. The adjusted odds ratio of shiftwork was 2.0 (95% CI) 1.1-3.4) for preterm birth and 2.1 (95% CI 1.1-4.1) for low birth weight. This association remained significant when the analysis was restricted to production workers or first order live births.

Complete primary structure of the sixth chain of human basement membrane collagen, alpha 6(IV). Isolation of the cDNAs for alpha 6(IV) and comparison with five other type IV collagen chains

Basement membranes were previously believed to contain five distinct type IV collagen subunits. We have recently isolated part of the cDNA for a novel type IV collagen, alpha 6(IV), and shown that COL4A6, the gene encoding this new chain, is deleted in Alport syndrome-associated leiomyomatosis (Zhou, J., Mochizuki, T., Smeets, H., Antignac, C., Laurila, P., de Paepe, A., Tryggvason, K., and Reeders, S. T. (1993) Science 261, 1167-1169). Here, we describe the entire human alpha 6(IV) cDNA and show that the gene encodes a classical type IV collagen with homology throughout its length to all the other five chains. There is a 21-residue signal peptide, a 1417-residue collagenous domain interrupted at 25 points, and a 228-residue carboxyl-terminal non-collagenous domain. When the complete primary structure of this new chain was compared with all the other known chains, it became clear that alpha 6(IV) has the most resemblance to alpha 2(IV) and alpha 4(IV). The evolution of the six chains was deduced, allowing a new classification of the type IV collagen family. The alpha 6(IV) chain is a candidate gene for X-linked Alport syndrome; knowledge of the complete structure of the chain will permit us to screen systematically for mutations in patients and to generate recombinant proteins and synthetic peptides for further study of cell-matrix interactions involving the alpha 6(IV) chain.

Myocardial stunning: association with altered gene expression

Regional and global myocardial ischemia and reperfusion have been demonstrated to induce expression of the stress response protein heat shock 70 (HSP70) and of immediate early genes, c-jun, c-fos, and c-myc. Because of the models that have been utilized, it has not been possible to discriminate whether this response is the consequence of ischemia, reperfusion, or abnormal hemodynamic stress superimposed on stunned myocardium. In a nonworking isolated and blood-perfused rat heart model, we evaluated the mRNAs for c-fos, c-myc, and hsp70. The heart was subjected to varying periods of ischemia and reperfusion. Significant increases in hsp70 and c-fos were observed, which increased with longer periods of ischemia. No significant increase in c-myc was measured. In addition, mRNA encoding the Ca2+/glucose responsive stress protein GRP78 was evaluated. No increase in this early response gene was noted despite the use of a model associated with cellular calcium loading. Based on these observations, we suggest that the induction of hsp70 and c-fos is the consequence of ischemia and reperfusion and not dependent upon an early hypertrophy response such as would be observed in afterload mismatching or on calcium loading. Further investigations are necessary to isolate the effects of ischemia from those of reperfusion.

The nonlinear dynamics of speech categorization

Little is known about the processes underlying the nonlinear relationship between acoustics and speech perception. In Experiment 1, we explored the effects of systematic variation of a single acoustic parameter (silent gap duration between a natural utterance of s and a synthetic vowel ay) on judgements of speech category. The resulting shifts in category boundary between say and stay showed rich dynamics, including hysteresis, contrast, and critical boundary effects. We propose a dynamical model to account for the observed patterns. Experiment 2 evaluated one prediction of the model, that changing the relative stability of the two percepts allows categorical switching. In agreement with the model; an increase in the number of stimulus repetitions maximized the frequency of judgments of category change near the boundary. Thus, a dynamical approach affords the rudiments for a theory of the effects of temporal context on speech categorization.

Effect of triiodothyronine on postischemic myocardial function in the isolated heart

Thyroid dysfunction has been shown to have a significant impact on hemodynamic status and cardiac function. The purpose of this study was to determine the influence of triiodothyronine (T3) on cardiac functional recovery after ischemia in a dose-dependent manner. Postischemic functional recovery was assessed in isolated rabbit hearts mounted in a modified Langendorff preparation. Left ventricular systolic, diastolic, and peak developed pressures were measured before and after ischemia, and calculated as a percentage of preischemic function. Two cohorts of hearts were studied: the first was exposed to warm ischemia until a myocardial contracture of 4 mmHg was produced; the second cohort was exposed to warm ischemia until a contracture of 15 mm Hg was observed. In each cohort, T3 was added to the perfusion solution after ischemia in a physiologic concentration (2.5 x 10(-9) g/mL; 1 x T3), as well as ten times (2.5 x 10(-8) g/mL; 10 x T3) and a hundred times (2.5 x 10(-7) g/mL; 100 x T3) the physiologic concentration. One group, given the carrier only but without T3, served as the control. Rabbit hearts exposed to a short period of ischemia (4-mmHg diastolic contracture) showed increased recovery with 1 x T3 and 10 x T3. 100 x T3 did not bring about improved left ventricular recovery versus that in the control group. Rabbit hearts in the 15 mm Hg-diastolic contracture cohort showed increased recovery with 10 x T3 but not with 1 x T3. 100 x T3 led to decreased recovery in this cohort versus that in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The nonlinear dynamics of speech categorization

Little is known about the processes underlying the nonlinear relationship between acoustics and speech perception. In Experiment 1, we explored the effects of systematic variation of a single acoustic parameter (silent gap duration between a natural utterance of s and a synthetic vowel ay) on judgements of speech category. The resulting shifts in category boundary between say and stay showed rich dynamics, including hysteresis, contrast, and critical boundary effects. We propose a dynamical model to account for the observed patterns. Experiment 2 evaluated one prediction of the model, that changing the relative stability of the two percepts allows categorical switching. In agreement with the model; an increase in the number of stimulus repetitions maximized the frequency of judgments of category change near the boundary. Thus, a dynamical approach affords the rudiments for a theory of the effects of temporal context on speech categorization.

Lipopolysaccharide induces substance P in sympathetic ganglia via ganglionic interleukin-1 production

The immune cytokine interleukin-1 (IL-1) causes a pronounced elevation in substance P (SP) immunoreactivity and the mRNA coding for its preprotachykinin precursor in cultured superior cervical (sympathetic) ganglia (SCG; Jonakait and Schotland, 1990; Freidin and Kessler, 1991; Hart et al., 1991). In this study we have investigated the possibility that the SCG can respond to other immune stimulators, notably lipopolysaccharide (LPS), a product of bacterial cell walls. LPS treatment of cultured SCG resulted in a dose-dependent increase in SP. However, LPS did not induce SP in the absence of non-neuronal cells, suggesting the necessity of a non-neuronal cell-derived intermediate. Since the LPS induction of SP was partially blocked by a specific IL-1 receptor antagonist (IL-1ra) and since LPS induced approximately an 8-fold increase in mRNA coding for IL-1 itself, we concluded that IL-1 is at least one of these LPS-induced intermediates. TNF-alpha, which also raises SP levels, may be another. IL-6, which may also be increased by LPS, does not increase levels of SP. The synthetic glucocorticoid hormone dexamethasone (DEX) blocks the LPS induction of SP with a Ki approximating 8 x 10(-11) M. The inhibition is due in part to the blockade of the LPS induction of ganglionic IL-1 mRNA. Moreover, inhibition of the LPS induction of SP by indomethacin implies mediation of the effect through prostaglandins. The inhibition by indomethacin suggests a non-monocytic cell source since prostaglandins are thought to restrict the LPS induction of monocytic IL-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Protection of the stunned myocardium. Selective nucleoside transport blocker administered after 20 minutes of ischemia augments recovery of ventricular function

BACKGROUND

Metabolic interventions capable of preventing ventricular dysfunction "stunning" or accelerating its functional recovery have potential clinical importance. Myocardial protection of the stunned myocardium has not been documented when drugs were administered only during postischemic reperfusion. The role of ATP depletion and release of purines in myocardial injury was assessed using the selective nucleoside transport blocker p-nitrobenzylthioinosine (NBMPR) in a combination with specific adenosine deaminase inhibitor erythro-9-[hydroxy-3-nonyl]adenine (EHNA) administered during reperfusion after reversible ischemic injury.

METHODS AND RESULTS

Sixteen anesthetized dogs were instrumented with minor axis sonocrystals and intraventricular Millar. Ventricular performance was determined, off bypass, from the slope of the relationship between stroke-work and end-diastolic length as a sensitive and load-independent index of contractility within physiological range. Hearts were subjected to 20 minutes' warm global ischemia and reperfused with warm blood treated with either saline (control group, n = 8) or saline containing 100 mumol/L EHNA and 25 mumol/L NBMPR (EHNA/NBMPR-treated group, n = 8). Myocardial biopsies were collected and analyzed for ATP and metabolites using high-performance liquid chromatography. Warm ischemia induced significant depletion of ATP (P < .05 versus preischemia) and accumulation of inosine at the end of ischemia (> 90% of total nucleosides) in both groups. Complete functional recovery was observed in the EHNA/NBMPR-treated group (P < .05 versus control group).

CONCLUSIONS

Selective entrapment of adenine nucleosides during postischemic reperfusion attenuated ventricular dysfunction (stunning) after brief global ischemia. It is concluded that nucleoside transport plays an important role in myocardial stunning, and its blockade augmented myocardial protection against reperfusion injury. Selective entrapment of endogenous inosine, generated during ischemia, represents an attractive therapeutic approach to the alleviation of postischemic dysfunction mediated by reperfusion in a wide spectrum of ischemic syndromes, including percutaneous transluminal coronary angioplasty and coronary artery bypass graft surgery.

Enhanced expression of human immunodeficiency virus type 1 correlates with development of AIDS

The progression to AIDS may be significantly related to the level of human immunodeficiency virus type 1 (HIV-1) replication. We have used quantitative cell culture and quantitative DNA and RNA PCR to measure viral load and expression in peripheral blood mononuclear cells obtained cross-sectionally and longitudinally from HIV-1-seropositive homosexual men enrolled in the Multicenter AIDS Cohort Study. Our results indicate that the number of circulating CD4+ T-lymphocytes producing HIV-1 increased as the total number of CD4+ T-cells declined. However, there was no correlation between the number of HIV-1-producing CD4+ cells and the duration of infection. Furthermore, the level of HIV-1 gag RNA increased as the disease progressed and CD4+ cell numbers declined. Subjects who remained asymptomatic with stable CD4+ cell counts, however, maintained a very low level of HIV-1 RNA expression during the entire period of follow-up (38-71 months). In contrast to viral RNA expression, the level of proviral DNA did not change significantly as the disease progressed. However, the level of proviral DNA was significantly higher in AIDS patients than in men who remained asymptomatic. Such increased levels of HIV-1 DNA were detected 34-68 months before the development of AIDS. These results support the role of HIV-1 RNA expression in the development of AIDS.

Effects of triiodothyronine supplementation after myocardial ischemia

Cardiopulmonary bypass causes a "euthyroid-sick" state characterized by low levels of circulating triiodothyronine. Triiodothyronine supplementation in this setting has been postulated to improve postischemic left ventricular function by increasing the availability of myocardial high-energy phosphates. These postulates have not been substantiated, however, using load-independent parameters of left ventricular function and analysis of high-energy phosphate metabolism. To test these hypotheses, 14 healthy pigs (30 to 40 kg) were placed on cardiopulmonary bypass and instrumented with left ventricular minor-axis ultrasonic crystals and micromanometer-tipped pressure catheters. Hearts were subjected to 30 minutes of global, normothermic ischemia. Triiodothyronine (0.1 mg/kg; n = 7) or placebo (n = 7) was administered in a random, investigator-blinded fashion at the removal of the aortic cross-clamp and after 60 minutes of reperfusion. Hemodynamic, metabolic, and ultrastructural data were obtained before ischemia and after 30, 60, 90, and 120 minutes of reperfusion. By 90 minutes of reperfusion left ventricular contractility had returned to preischemic levels in hearts supplemented with triiodothyronine, despite postischemic myocardial adenosine triphosphate levels of 50% to 60% of baseline in both groups. Ultrastructurally, the sarcoplasmic reticulum and mitochondria were significantly better preserved in the group treated with triiodothyronine. This study suggests that triiodothyronine supplementation significantly enhances postischemic left ventricular functional recovery and that this recovery is due to mechanisms other than enhanced availability of myocardial high-energy phosphates.

Neuronal and glial marker proteins in encephalopathy associated with acute liver failure and acute hyperammonemia in the rabbit

Neuronal and glial cell marker proteins were quantified in order to evaluate the possibility of increased proteolysis in the brain of rabbits with acute liver failure and acute hyperammonemia. Acute liver failure was induced by a two-stage devascularization procedure. Acute hyperammonemia was induced by a prolonged infusion of ammonium acetate, which simulates the plasma ammonia level in acute liver failure. Control animals received an infusion of sodium/potassium acetate. After development of severe encephalopathy, the animals were sacrificed (13.7 +/- 1.3 hours for rabbits with acute liver failure and 20.2 +/- 0.8 hours for rabbits with hyperammonemia) (x +/- S.E.M./n = 6) and their brains were dissected into cerebral cortex, hippocampus, cerebellum and brain stem. The total protein content and the concentrations of the neuronal cell marker proteins NSE (neuron specific enolase), NF68 and NF200 (68 kD and 200 kD neurofilament polypeptides) and the glial cell marker proteins GFAP (glial fibrillary acidic protein) and S-100 were determined. Total protein content was decreased in the brain stem in acute hyperammonemia only. The content of neuronal and glial cell markers was not affected in either of the two conditions. However, low molecular weight proteolytic fragments of the NF 68 kD polypeptide were observed in the hippocampus of three out of six animals in both experimental groups. No proteolytic degradation of GFAP was observed. The results show that, in experimental encephalopathy due to acute liver failure and acute hyperammonemia, no major changes occur in the marker proteins. The finding of proteolytic fragments of the NF68 polypeptide indicates that the neuronal population is affected prior to glial alterations. These findings are in agreement with the concept that acute hepatic encephalopathy is reversible and induces only slight structural changes.

[The multiplication of Sindbis virus in BHK-21 cell]

One step growth curve of Sindbis virus (SbV) in BHK-21 cells showed that a lot of progeny viruses could be observed at 2 hr. after infection. The titer of virus reached the highest about 10(9)TCID50/ml at 6hr. post infection. The viral morphological characters and morphogenetic process in BHK-21 cells were examined by electron microscopic techniques. The dynamics of viral proteins synthesis and the effect on host cell were studied and discussed in this paper.

Cloning and analysis of the leuB gene of Leptospira interrogans serovar pomona

The leuB gene of Leptospira interrogans serovar pomona strain kenniwicki has been cloned on a 9.5 kb plasmid, pWVL1, by complementation of Escherichia coli leuB mutants. Subcloning and Tn5 mutagenesis showed that the region required for complementation was approximately 1.2 kb in length. Enzyme assays showed that the product of the cloned gene was a beta-isopropylmalate dehydrogenase. Defects in the leuA, leuC and leuD genes of E. coli were not complemented by pWVL1. The nucleotide sequence of the leuB-complementing region and surrounding DNA has been determined. Three open reading frames were found which encode proteins of 40.9, 38.8 and 15 kDa. Analysis of subclones containing nucleotide deletions of varying sizes showed that only the 38.8 kDa protein was necessary to obtain complementation of E. coli leuB mutations. The PIR data base was searched and the enzyme 3-isopropylmalate dehydrogenase from six different micro-organisms was found to share significant amino acid sequence similarity (43-57%) with the 38.8 kDa L. interrogans leuB gene product. The organization of the leucine biosynthetic genes in L. interrogans differs from that found in E. coli, Salmonella typhimurium and Bacillus subtilis.

Myocardial stunning and preconditioning: age, species, and model related differences: role of AMP-5'-nucleotidase in myocardial injury and protection

Mechanisms of myocardial stunning include myocardial adenosine triphosphate (ATP) depletion, catecholamine release, and oxygen free radical formation. Although the latter is the most widely supported mechanism, levels of 5'-nucleotidase (directs AMP dephosphorylation) are inversely related to functional recovery following ischemia and may also have a role in ischemic injury. Previous studies reveal that 5'-nucleotidase levels increase with age and also vary with species. An inhibitor of this enzyme (alpha, beta methylene adenosine 5'-diphosphate) was effective in maintaining AMP levels in vitro but was ineffective in dogs due to limited permeability. Observed species-specific differences in recovery from myocardial stunning may be related to differences in AMP accumulation and subsequent metabolism. Species showing improved recovery from stunning may accumulate AMP as a result of feedback inhibition of 5'-nucleotidase. Using a model of extreme experimentally-induced ischemia, we found that adenosine treatment allowed full recovery of ventricular function within 30 minutes, probably by entrapping ATP catabolites. Similarly, enhancement of adenosine production by N-diarylalkylpeprazine derivatives has also been shown to be cardioprotective in the setting of global normothermic ischemia. Novel strategies for pharmacological intervention in the ATP catabolic pathway should use animal models involving species that are tolerant to myocardial stunning.

Effects of triiodothyronine on stunned myocardium

Administration of thyroid hormone, triiodothyronine (T3), causes numerous cardiovascular effects such as increases in stroke volume, cardiac output, heart rate, and myocardial contractility, and decreases in systemic vascular resistance. Along with other stressors, cardiopulmonary bypass (CPB) has been associated with reduced levels of T3. We examined the effects of T3 on early postischemic myocardial recovery in rabbit hearts subjected to crystalloid perfusion to simulate a low T3 state, and in pig hearts following global ischemia due to CPB. Studies using the former system showed that T3 administration results in significantly improved developed pressure after reperfusion of mildly ischemic hearts compared to controls, without producing inotropic effects. In more severely stunned rabbit hearts, physiologic and 10 times physiologic doses of T3 produced significantly improved (p < 0.05) stroke work end-diastolic length compared to placebo treatment. T3 treated pigs undergoing CPB and subjected to 30 minutes of global normothermic ischemia experienced significantly enhanced recovery of left ventricular contractility compared to controls at 90 and 120 minutes post reperfusion. Neither placebo nor T3 affected myocardial adenosine triphosphate levels. These data show that T3 enhances recovery from myocardial stunning without producing acute inotropic effects.

Genetic polymorphism of complement component C6, C7 and C8(1) in Chinese Han population in northeast China

Distributions of complement phenotypes, C6, C7, and C8(1) were studied using thin agarose gel isoelectric focusing (AGIEF) or ultra-thin polyacrylamide gel isoelectric focusing (PAGIEF) and subsequent immunoblotting techniques in 203 Chinese Han population in Liaoning Province of northeast China. The gene frequencies were as follows: C6*A 0.4704, C6*B 0.5049, C6*B2 0.0148, C6*B3 0.0049, and C6*M 0.0049; C7*1 0.8251, C7*2 0.1108, C7*3 0.0320, and C7*4 0.0320; C8(1)*A 0.5567 and C8(1)B 0.4433, respectively. All the observed numbers of the phenotypes were in agreement with the expected numbers under the Hardy-Weinberg equilibrium. The gene frequencies among Chinese subpopulations and other various populations were compared.

Polyethylene glycol-conjugated superoxide dismutase attenuates reperfusion injury when administered twenty-four hours before ischemia

Covalent linkage of polyethylene glycol to superoxide dismutase prolongs the serum half-life of the enzyme and may facilitate intracellular access. We tested the myocardial protective effect of polyethylene glycol superoxide dismutase administered once, 24 hours before ischemia. Because hearts were studied ex vivo in a crystalloid perfused system, cardioprotection could be ascribed to intramyocardial or membrane-bound polyethylene glycol superoxide dismutase accumulation. Thirty isolated rabbit hearts from the four following groups were studied: (1) control: untreated rabbits (n = 7); (2) PEG-control: 24-hour intravenous preinfusion of methoxypolyethylene glycol 5000 (5 mg/kg) to examine the effect of polyethylene glycol alone, without conjugation to superoxide dismutase (n = 8); (3) PEG-SOD 10,000: 24-hour preinfusion of polyethylene glycol superoxide dismutase (10,000 U/kg) (n = 8); (4) PEG-SOD 30,000: 24-hour preinfusion of polyethylene glycol superoxide dismutase (30,000 U/kg) (n = 7). After measurement of baseline function with use of an intraventricular balloon, hearts were subjected to normothermic ischemia until a 4 mm Hg rise in intracavitary pressure was observed. Function was assessed at 15-minute intervals throughout reperfusion and expressed as percent return of developed pressure. After 60 minutes of reperfusion, recovery of function was greater for the PEG-SOD 30,000 group (85.6% +/- 2.6%) when compared with either the untreated or PEG-control group (68.9% +/- 2.3% and 71.4% +/- 2.0%, respectively). A similar difference was seen throughout reperfusion. Although an improved return of function was shown in the lower dose PEG-SOD 10,000 group, the margin of difference when compared with any of the control groups was determined to be insignificant at all times of reperfusion and at 60 minutes (75.9% +/- 3.2%). These data demonstrate that high, but not low, doses of polyethylene glycol superoxide dismutase significantly reduce reperfusion injury when administered 24 hours before initiation of global ischemia. Moreover, since the perfusate was superoxide dismutase free, this effect was most likely intramyocardial or membrane bound and therefore might be added to protection afforded by circulating superoxide dismutase.