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.

A technique to harvest viable tracheobronchial epithelial cells from living human donors

The ability to obtain airway epithelial cells from the lower respiratory tract in living human donors will facilitate study of the biologic properties of these cells. We report our experience harvesting tracheobronchial epithelial cells from living human donors by brushing the mucosal surface of the trachea and mainstem bronchi. Cells were obtained on 21 occasions from 18 healthy adult subjects under direct vision with a brush-tipped catheter during fiberoptic bronchoscopy. The average number of cells harvested per subject was 14 +/- 2 x 10(6), and cell viability determined by trypan blue exclusion averaged 36 +/- 4%. Of note, cell viability was significantly enhanced when lidocaine was confined to the nares. Lidocaine was also observed to diminish cell viability in vitro in a dose-dependent fashion. Morphologic and staining properties were used to classify harvested cells into the three major cell types present in the mucosa (i.e., ciliated, secretory, and basal cells). All three subtypes were obtained. The percentage of ciliated, secretory, and basal-like cells was 24 +/- 2%, 11 +/- 1%, 29 +/- 1%, respectively, while the remaining 36% were difficult to type. In one subject in whom brushing was performed on three occasions over a 7-wk period, the percentage of each of the three subtypes was similar across procedures. Harvested cells could be successfully placed in primary culture with a plating efficiency of 50 to 60% and could be subcultured for up to seven passages. Acutely dissociated cells could be used to study the beta-adrenergic receptor adenylyl cyclase system since they produced cAMP in response to isoproterenol.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of a novel synapse-specific protein. II. cDNA cloning and sequence analysis of the F1-20 protein

The F1-20 protein is a novel neuronal-specific, synapse-associated protein that is expressed nonuniformly in mouse brain. Expression of the F1-20 protein is developmentally regulated in a pattern coincident with active synaptogenesis and synaptic maturation. Here we report the cloning of the cDNA sequence for the F1-20 protein. We found two distinct isoforms of F1-20 cDNA that differed by the presence of 15 additional nucleotides, which does not interrupt the open reading frame. RNase protection analysis and PCR amplification of mouse brain RNA revealed that both isoforms are present in cellular RNA. It is likely that the two F1-20 mRNA isoforms are derived from RNA splicing events utilizing alternative 3' acceptor sites. Analysis of the deduced amino acid sequence for the complete open reading frame revealed that the predominant F1-20 mRNA encodes an 896 amino acid polypeptide with a molecular weight of 91,319 Da. The deduced amino acid sequence does not contain a signal sequence, or any extensive hydrophobic regions. The deduced amino acid sequence does contain a number of consensus sequences for protein kinases. Searches of the protein and nucleic acid sequence data bases revealed that the F1-20 protein has not been previously characterized at the primary structure level, although a weak similarity was found between rabbit calpastatin and the C-terminal portion of the F1-20 protein. We then determined biochemically that the F1-20 protein is a substrate for Ca(2+)-dependent proteolysis, which is specifically inhibited by calpain inhibitors in vitro. This indicates that the F1-20 protein is a substrate for neuronal calpain. We observed that treatment of a synaptosomal lysate with alkaline phosphatase led to an increase in the electrophoretic mobility of the F1-20 protein, as well as to an increase in the sharpness of the electrophoretic band. This indicates that the F1-20 protein is phosphorylated in vivo.

Characterization of a novel synapse-specific protein. I. Developmental expression and cellular localization of the F1-20 protein and mRNA

A molecular description of the nerve terminal will be required to understand synaptic function fully. The goals of this study were to contribute toward such a description by characterizing a novel synapse-specific protein. A monoclonal antibody library was screened for antibodies to synaptic proteins. The antibodies were then used to isolate cDNA clones by expression screening. Here we report a detailed characterization of the protein reactive with monoclonal antibody F1-20. Immunohistochemical and biochemical analyses revealed that the F1-20 protein is synapse associated. Western blot analyses revealed that the F1-20 protein is a brain-specific polypeptide with an apparent molecular weight on SDS-PAGE of 190,000 Da. Northern blot analyses indicated that probes generated from an F1-20 cDNA clone hybridize to a single brain-specific mRNA of approximately 4.8 kilobases. In situ hybridization experiments demonstrated that F1-20 mRNA expression is neuronal specific. Northern and Western blot analyses indicated that F1-20 mRNA levels increase abruptly at postnatal day 4 and protein levels increase abruptly at postnatal day 7. This corresponds to a period of active synaptogenesis and synaptic maturation in the mouse CNS. We characterized the neuroanatomical distribution of the F1-20 protein by immunohistochemistry, and of the F1-20 mRNA by in situ hybridization. We found that the F1-20 mRNA and protein are expressed nonuniformly in brain. Variation in the expression of the F1-20 protein is complex and reveals patterns also exhibited by probes directed against other synapse-associated molecules. The highest levels of F1-20 protein are found in the cortically organized regions of the brain. The highest levels of F1-20 mRNA are found in long-distance projection neurons. There is also variation in the expression of F1-20 mRNA between different classes of large output neuron, as well as extensive variation in the expression of F1-20 mRNA between different nuclear groups.

Inhibitory effects of diallyl sulfide on the metabolism and tumorigenicity of the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in A/J mouse lung

Diallyl sulfide (DAS), a component of garlic oil, has been shown to inhibit tumorigenesis by several chemical carcinogens. Our previous work demonstrated that DAS inhibited the metabolic activation of carcinogenic nitrosamines, including the tobacco-specific 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in rat lung and nasal mucosa microsomes. In the present study, the effects of DAS on the tumorigenicity and the metabolism of NNK in A/J mouse lung were examined. Female A/J mice at 7 weeks of age were pretreated with DAS (200 mg/kg body wt in corn oil, p.o) daily for 3 days. Two hours after the final DAS treatment, the mice were either given a single dose of NNK (2 mg/mouse, i.p.) and kept for an additional 16 weeks for determining the production of pulmonary tumors, or were killed immediately so as to measure the microsomal activity in metabolizing NNK. In comparison to the vehicle control group, DAS pretreatment significantly decreased the incidence of NNK-induced lung tumors (37.9 versus 100%) and the tumor multiplicity (0.6 versus 7.2 tumors/mouse). In pulmonary metabolism of NNK, DAS pretreatment reduced the rates of formation of keto aldehyde, keto alcohol, NNAL-N-oxide, and NNK-N-oxide by 70-90%. In addition, the formation of NNK oxidative metabolites from NNK in the liver microsomes from DAS-pretreated mice was remarkably reduced. DAS also inhibited the metabolism of NNK in mouse lung microsomes in vitro. These results demonstrate that DAS is an effective chemopreventive agent against NNK-induced lung tumorigenesis, probably by inhibiting the metabolic activation of NNK.

Characterization of hepatitis B virus capsid particle assembly in Xenopus oocytes

Little is known about the assembly of the 28-nm nucleocapsid or core particle of hepatitis B virus. Here we show that this assembly process can be reconstituted in Xenopus oocytes injected with a synthetic mRNA encoding the hepatitis B virus capsid protein (p21.5). Injected oocytes produce both a nonparticulate p21.5 species (free p21.5) and capsid particles. We describe rapid and simple methods for fractionating these species on a small scale either with step gradients of 10 to 60% (wt/vol) sucrose or by centrifugation to pellet the particles, and we characterize the oocyte core particles. Free p21.5 exhibits chemical and physical properties distinctly different from those of particles. Free p21.5 is partially cleaved by proteinase K, whereas core particles are almost completely resistant to cleavage. This suggests that the carboxyl-terminal protamine region, the main target for proteases within p21.5, is exposed in free p21.5 but faces the interior of the p21.5 core particle. Finally, pulse-chase experiments demonstrated that free p21.5 can be chased almost quantitatively into core particles, establishing that free p21.5 is fully competent to form particles and represents an assembly intermediate on the pathway for core particle formation. However, core particle assembly appears very dependent on p21.5 concentration and is rapidly compromised if the p21.5 concentration is lowered. The advantages of oocytes for studying assembly are discussed.

Spatial-light-modulator-based electro-optical imaging system

We describe a novel electro-optical system that can image objects over a long range of distance without involving any mechanical movement.

Cloning and partial sequencing of the porcine growth hormone (pGH) gene from pituitary gland

High molecular weight DNA was isolated from porcine pituitary gland, and a genomic library was constructed using lambda EMBL3 as cloning vector. Five positive clones were identified by in-situ hybridization with the full-length pGH cDNA as the probe. Dot-blot hybridization, restriction analysis, and Southern hybridization showed that one of the positive clones contained the entire pGH gene. A subclone that contained the upstream sequence from the SmaI site of pGH gene was identified, and part of it was sequenced. We also compared the sequence of our pGH gene with the corresponding sequence of the published pGH gene.

[Psychosocial stress and essential hypertension]

A case-control study of 72 pairs indicated that stress events in daily life stimulative factor might induce the development of hypertension in susceptible persons. The sustained stress of tension and anxiety and passive mood of psychodefence could be the psychological factors inducing hypertension. Personality, as a mediated variable, has an important influence on the initiation and progress of hypertension.

Prospective multicenter study on isolation of human immunodeficiency virus type 1 from homosexual men after seroconversion

A prospective multicenter study was undertaken to isolate human immunodeficiency virus type 1 (HIV-1) from 45 homosexual men for a period of 30 months after seroconversion. Efficiency of HIV-1 isolation from peripheral blood mononuclear cells was relatively stable over time, ranging from 64% at the time of seroconversion to more than 82% after 18 months of seroconversion. However, Kaplan-Meier analysis of HIV-1 culture data indicates that the cumulative proportion of HIV-1 culture positivity at 3, 6, 12, and 18 months after seroconversion was 62, 65, 84, and 92%, respectively. No significant correlation was observed between the presence of HIV-1 p24 antigen in serum, or numbers of CD4+ and CD8+ blood lymphocytes, and HIV-1 isolation within this period of time. These data suggest that HIV-1 viremia in homosexual men gradually increases to almost 100% culture positivity by 18 months after seroconversion.

[Synthesis of delta virus cDNA of China Sichuan strain]

delta virus cDNA of China Sichuan strain, 1.2 kb in length, was synthesized by extraction of RNA from liver tissue in a patient with subacute severe hepatitis, followed by reverse transcription and polymerase chain reaction (RT-PCR). The result was confirmed by Southern blot hybridization using 32P and biotin labelled delta virus cDNA (HN88, cloned in USA) probes respectively.

Bovine endozepine potentiates morphine analgesia in mice

This paper describes the influence of bovine endozepine (BEP) on the analgesic effect of morphine. The intraventricular administration of BEP between doses of 2-4 nmole in mice resulted in the potentiation of the morphine-analgesic effect. The basic pain threshold did not change when BEP was given alone, thus indicating that BEP is unable to elicit analgesic effect alone. Intravenous injection of BEP in the dose range of 5-7.5 mg/kg also potentiated the analgesic effect of morphine. These observations suggest that endozepine can act as a regulator of pain.

Phytochrome-mediated swelling of etiolated leaf protoplasts and its possible biological significance

Red light, mediated by the photoreceptor phytochrome, induces maize leaf unrolling as well as leaf expansion. Protoplasts prepared from maize leaves still in the rolled condition swell in a red-far red photoreversible manner indicating that phytochrome mediates this phenomenon. To determine if protoplast swelling is related to leaf unrolling, leaf expansion, or both, we compared red-light induced swelling of protoplasts from rolled maize leaves to protoplasts prepared from tissues that are known to grow in response to light but do not unroll. We also compared the swelling response of protoplasts from rolled vs. unrolled leaves. In all cases, we found that swelling correlated with the unrolling response and not leaf expansion.

[Anastomosis of peripheral nerves by fibrin glue. An experimental study]

This paper reports the results of experimental research of anastomosing peripheral nerves by fibrinogen glue. In research of 80 sciatic nerves of 40 rats, taking epineurial suture as a control, we welded the nerves by domestic glue or Tissu-col from abroad separately to make an evaluation and survey of nerve conduct speed and gastrocnemius weight and the histology and ultrastructure. It has demonstrated that this is a more practical method for nerve repair.

[Production and characterization of anti-human hepatocellular carcinoma monoclonal antibodies]

The hepatocellular carcinoma (HCC) cell line, QGY-7703, derived from a Chinese patient, was used to immunize the BALB/c mice. Fifteen hybridomas producing McAb that reacted with QGY-7703 cells were isolated from 858 hybridomas created in three cell fusions. In further studies two McAb, namely, AQGY1 and A-QGY2, were selected which specifically stained HCC cells grown in vitro. The reactivity of these McAb was not removed by the absorption by homogenates of the normal liver, but was by homogenates of HCC cells. A-QGY1 and A-QGY2 also reacted definitely with HCC cells in liver tissues of HCC patients, but neither with other cells in the tissues nor with nontransformed liver tissues of the same patients. Furthermore these two McAb stained the adult or fetal liver tissues, nor all of the other normal or tumor tissues that had been tested. Blocking and absorbing experiments revealed that A-QGY1 and AQGY2 antigens had no immunohomogenicity with antigens such as HBsAg, HBcAg, HBeAg, AFP and CEA. The specificity of these two McAb may be used potentially for the sero diagnosis, histologic identification, radioimmunoimaging and destruction of human hepatocellular carcinoma.

[Primary serologic investigation of HBV-like virus existence in domestic animals and fowls]

Using the reagent kits for detecting human HBV, primary serologic investigation was made in 6 kinds of domestic animals and fowls (total 673) by ELISA, spot hybridization and immuno-electronmicroscopy. The results showed that some sera samples of pigs, rabbits, chicken and geese were HBsAg, HBeAg positive and positive for spot hybridization by using 3(2)P-HBV-DNA probe, which suggested that HBV-like viruses might exist in those domestic animals and fowls. HBV-like virus particles were seen in one pig serum sample which was HBsAg positive. The particles could be divided into three forms in shape, large spherical particle (40-55nm), small spherical particle (20-30nm) and short filament particle. The further studies are needed.

[Treatment of orthostatic dysregulation by the principle of bu-shen yi-qi]

Sixty cases of orthostatic dysregulation was randomly divided into treatment group (TG) and control group (CG), both 30 cases. Traditional Chinese medical herbs were used for TG under the principle of Bu-Shen Yi-Qi, and routine treatments such as oryzanol, vitamin B1 and B6 were applied to CG. After a curable stage of one month, the results showed that 16 of TG and 4 of CG were cured; 8 of TG and 6 of CG improved. The cure rate and the effective rate were significantly better in TG than in CG (P less than 0.01). 43 cases (71.7%) clinically expressed mild anemia. Before and after the treatment, the values of RBC, SI, Hb, SIBC, MCH in 20 cases of TG turned significantly better (P less than 0.01), but 17 cases of CG remained unchanged under the principle. The authors purposefully selected herbs that contain rich trace elements. For example, iron is an important element of Hb and zinc is an element in proteotic nucleicacidase. The quantity of zinc in body is related to many enzyme activities. Since these herbs could increase chronotropic effect of blood vessels and cure anemia, they could be used to cure patients with orthostatic dysregulation.