[Endothelin-1 induces chemotaxis of pulmonary artery smooth muscle cells]

Migration of pulmonary artery smooth muscle cells (PASMC) and their precorsors might be an important mechanism of pulmonary vascular structural remodelling associated with hypoxic pulmonary hypertension (HPH). Endothelin-1 (ET-1) plays an important role in the pathogenesis of HPH. This study observed that ET-1 induced chemotaxis of PASMC in a dose dependent manner. The maxium chemotactic response of PASMC to ET-1 occured at a concentration of 10(-9) mol/L. The chemotactic activity of ET-1 is weakened, when its concentration is higher than 10(-9) mol/L. BQ123, a specific antagonist of ETRA, significantly inhibited the chemotaxis of PASMC induced by ET-1, which indicates that the chemotactic activity of ET-1 may be mediated by ETRA. Hypoxia enhanced the chemotaxis of PASMC induced by ET-1. This study suggests that ET-1 and hypoxia might stimulate the migration of PASMC and/or its precorsor. The further mechanism is under study.

Receptor-associated Mad homologues synergize as effectors of the TGF-beta response

Transforming growth factor-beta TGF-beta is the prototype for a family of extracellular proteins that affect cell proliferation and tissue differentiation. TGF-beta-related factors, including BMP-2/4, Dpp and activin, act through two types of serine/threonine kinase receptors which can form a heteromeric complex. However, the mechanism of signal transduction by these receptors is largely unknown. In Drosophila, Mad is required for signalling by Dpp. We have isolated complementary DNAs for four human Mad homologues, one of which, hMAD-4, is identical to DPC-4, a candidate tumour suppressor. hMAD-3 and -4 synergized to induce strong ligand-independent TGF-beta-like responses. When truncated at their carboxy termini, hMAD-3 and -4 act as dominant-negative inhibitors of the normal TGF-beta response. The activity of hMAD-3 and -4 was regulated by the TGF-beta receptors, and hMAD-3 but not hMAD-4 was phosphorylated and associated with the ligand-bound receptor complex. These results define hMAD-3 and -4 as effectors of the TGF-beta response and demonstrate a function for DPCA-4/hMAD-4 as a tumour suppressor.

A comparative study of glioma cell lines for p16, p15, p53 and p21 gene alterations

A total of 10 glioma cell lines were examined for alterations of the p16, p15, p53 and p21 genes, which are tumor suppressor genes or candidates with direct or indirect CDK-inhibitory functions. Genetic alterations (deletions or mutations) were frequently seen in the p16, p15 and p53 genes in these cell lines, but not in the p21 gene. When the states of the p16, p15 and p53 genes were compared among cell lines, all the cell lines showed abnormalities in at least 1 gene, often in 2 or 3 genes coincidentally, suggesting that dysfunction of these genes is closely related to glioma cell growth. Although alteration of all 3 genes was most frequent, there were cell lines having either p16/p15 or p53 or pl6 and p53 gene alterations, suggesting that the time order of these genetic alterations was variable depending on the cell line. Among cell lines examined, one with homozygous p53 gene deletion seemed of particular practical value, since such a cell line might be useful in various studies, including investigation of the functions of various mutant p53 genes in the absence of heteromeric protein formation. On examination of the primary tumor tissues, the same alterations of the p16/p15 and p53 genes as detected in the cell lines were demonstrated in all 6 cases examined: p16/p15 gene deletion in 1, p16 gene mutation in 1 and p53 gene mutations in 5 cases. This suggested that the p16/p15 and the p53 gene alterations and their combinations in at least some glioma cell lines reflected those in the primary glioma tissues.

Competition for a unique response element mediates retinoic acid inhibition of vitamin D3-stimulated transcription

We have identified a novel steroid hormone response element in the avian beta3 integrin promoter. This sequence, comprising three hexameric direct repeat half-sites separated by nine and three nucleotides binds vitamin D receptor (VDR)-retinoid X receptor (RXR) and retinoic acid receptor (RAR)-RXR heterodimers. VDR-RXR binds direct repeats separated by three base pairs, and RAR-RXR recognizes half-sites separated by nine bases, whereas the central half-site interacts with both heterodimers. Retinoic acid and 1, 25-dihydroxyvitamin D3 activate both a genomic fragment including the transcriptional start site and an oligonucleotide containing the three repeats, linked to a heterologous promoter. Co-addition of the steroids produces neither synergy nor an additive effect; rather the result equals that for retinoic acid alone. Scatchard analysis demonstrates that RAR-RXR has greater affinity than VDR-RXR for the composite element. Based on these findings we propose a model in which there is specific, polarity-defined binding of VDR-RXR and RAR-RXR to three half-sites, which form two overlapping steroid response elements, with the central half-site common to both. Our results identify a novel mechanism by which one steroid hormone can modulate the activity of a second, by competing for a shared half-site in a composite response element.

Dot-immunogold filtration assay as a screening test for syphilis

A dot-immunogold filtration assay (DIGFA) for the rapid detection of reaginic antibody in the serum of syphilitic patients was developed. The assay was simple, rapid, and reproducible. The test completion time was 2 min, and the assay required no equipment. The positive dot was very obvious, and the results could easily be determined with the naked eye. A total of 350 serum samples were examined by DIGFA, the rapid plasma reagin test, and the fluorescent treponemal antibody-absorption test. The levels of agreement between DIGFA and the rapid reagin test and between DIGFA and the fluorescent treponemal antibody-absorption test were 100 and 98%, respectively. The results of clinical application indicated that DIGFA could be used as a routine screening test for syphilis.

Structure of a D-protein gene and amino-acid sequences of the highly repetitive D-proteins secreted by the accessory glands of the mealworm beetle

The D-group proteins form the major component of the proteinaceous secretion of the tubular accessory glands of the yellow mealworm beetle, Tenebrio molitor. In a previous paper, we reported the sequence of two D-protein cDNAs and their inferred translation products. Both proteins contain three highly repetitive domains (A, A' and B). In this paper, we present the cDNA-inferred sequences of 8 more D-proteins, none of which contains an A' domain. We also present the structure of a D-protein gene. Southern analysis suggests that genes coding for an A' domain are relatively rare. Genes with a total of 7 or 8 (A + B domain) repeats seem most common.

[Commodity identification of semen Plantaginis and herba Plantaginis]

The Semen Plantaginis from 29 provinces and regions and the Herba Plantaginis from 18 provinces and regions in our country were identified, and the main commodities of these two crude drugs are described in this paper. The identification may serve as a scientific basis for expanding new drug resources.

Hypoxia and endothelin-1 stimulate DNA synthesis of pulmonary artery smooth muscle cells

Hypoxia and endothelin-1 (ET-1) are associated with constriction of pulmonary vasculature both in vivo and in vitro. However, the role of hypoxia and ET-1 in the vascular remodelling during the development of pulmonary hypertension is unclear. This study demonstrated that ET-1 (0.1 nmol/L to 100 nmol/L) increased the [3H] thymidine uptake in a dose-dependent manner in cultured bovine pulmonary artery smooth muscle cells (PASMC), which was enhanced by exposing PASMC to hypoxia (2% O2, 93% N2, 5% CO2). BQ123, the specific antagonist of endothelin receptor subtype A, eliminated the ET-1 medicated proliferation of PASMC and the cooperative effect of hypoxia. Some dilatory drugs could inhibit the mitogenic effect of ET-1. We also observed that hypoxia significantly increased [3H]thymidine uptake in PASMC without ET-1 and BQ123 could inhibit this effect. Radioimmunoassay suggested that there was an autocrine of ET-1 in cultured PASMC which was enhanced by hypoxia significantly.

In vivo inhibition of hepatitis B viral gene expression by antisense phosphorothioate oligodeoxynucleotides in athymic nude mice

Antisense oligodeoxynucleotides strategies have been used both to study normal gene function and to block gene expression therapeutically. We have previously shown that a number of antisense oligonucleotides against hepatitis B virus (HBV) mRNA are able to inhibit viral gene expression in vitro. Here we report the establishment of an animal model producing HBV markers in athymic nude mice and inhibition of HBV gene expression and replication by antisense DNA in vivo. 2.2.15 cells (Hep-G2 cell line transfected with HBV genomes) were injected subcutaneously (s.c.) into athymic BALB/c nude mice at a total cell number of 0.5-1 x 10(8) per mouse. Transplanted tumours developed about 2 weeks after inoculation. Hepatitis B surface and e antigens (HBsAg and HBeAg), as well as HBV DNA, could be detected in the circulation of tumour-bearing mice. Hepatitis B surface antigen and hepatitis B core antigen (HBcAg) were demonstrated in tumour cells. After 10 days of tumour growth, antisense phosphorothioate oligonucleotide, complementary to the cap site of the SP II promoter of HBV mRNA, were injected by infiltration into or around the tumour as a daily dose of 20 micrograms per gram body weight. Treatment for a total of 10 days resulted in an effective inhibition of viral replication and gene expression. These results suggest therapeutic potential for antisense oligomers in the treatment of patients who are chronically infected with HBV.

Cooperative medical schemes in contemporary rural China

Improvements in rural health care in China in the 1950s, 1960s and 1970s were largely due to the development of cooperative medical schemes (CMSs) and the establishment of a three-tier rural health network. Since the economic reforms were instituted in the late 1970s, the financing and delivery of rural health services have seen many changes, some positive, others not. Most CMSs have collapsed. In the absence of CMSs, the rural population has to pay for health care out-of-pocket and poor families have greater difficulty in getting access to essential health care. In the meantime, emphases of health services have tended to shift from lower to higher levels, from preventive to curative services, and from planning and management to market forces. This paper outlines the evolution of CMSs, reasons for their collapse, and their likely impact on rural health services. The main focus is on the development of a new generation of rural cooperative health care schemes, given their importance in the process of consolidating the rural three-tier health network after the impact of the economic reforms: the characteristics of some schemes, the apparent conditions for success, and government policy towards the development of cooperative health care financing are presented.

[Clinical evaluation of serum collagen type IV in diagnosing liver fibrosis]

Serum collagen type IV (CIV) levels determined by one step sandwich EIA kit were compared with the serum procollagen type III (PCIII) and hyaluronic acid (HA) in 114 patients with various liver diseases, 30 patients without liver diseases (NL) and 30 controls.

RESULTS

serum CIV was significantly increased in chronic active hepatitis, liver cirrhosis and primary hepatic carcinoma. So were PCIII and HA. Serum CIV PCIII and HA were found to be closely related to the degree of fibrosis in 69 patients' liver biopsy studies, but no correlation could be found between these 3 markers. The sensitivity of CIV, PCIII, HA in detecting liver fibrosis were 73.9%, 67.4%, 67.4% with specificity of 95.7%, 91.3%, 100.0% respectively. The early diagnostic value of CIV is better than PCIII and HA; their combination could further raise the diagnostic sensitivity to more than 90.0%.

Intracranial germ cell tumors: detection of p53 gene mutations by single-strand conformation polymorphism analysis

Using polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis, p53 gene mutation was examined in 12 intracranial germ cell tumors (5 yolk sac carcinomas and 7 germinomas), many of which were derived from young patients in the first to the second decade. A total of 10 mutations were detected in 4 of the 12 cases and, in 3 of them, the mutations were multiple or tandem. Among the 10 mutations, 7 were missense, 1 was splicing and 2 were silent. The 7 missense mutations were located at previously proposed hot spot codons or in their vicinity or, when outside the hot spots, at a codon encoding an amino acid conserved in most vertebrates. These findings suggested that all 7 missense mutations may actually give rise to functional alteration of the p53 protein. The splicing mutation was considered to be a germ-line mutation, though its biological effect was equivocal, since the neoplastic tissue contained an additional mutation. The pattern of the mutations was predominancy of G:C-A:T transition with frequent involvement of the CpG site. These mutations were more frequently detected in yolk sac carcinomas (60%; 3/5 cases) than in germinomas (14%; 1/7 cases), suggesting that the contribution of the p53 mutation to carcinogenesis differed with the histological type of the intracranial germ cell tumor.

[Study on the effect of endothelin and nitric oxide on DNA synthesis of pulmonary artery smooth muscle cells and modulation of hypoxia]

Increasing vasoconstriction and vascular remodeling of pulmonary vasculature are main characteristics of hypoxic pulmonary hypertension (HPH). Basal pulmonary circulatory tone is maintained by a dynamic balance of vasoconstrictors and vasodilators acting on the pulmonary vascular smooth muscle cells. Endothelin-1 (ET-1) and nitric oxide (NO) are the most important endothelium-derived vasoconstrictor (EDCF) and vasodilator (EDRF). In this report, we studied the effect of ET-1 and NO on hypoxic pulmonary vascular remodeling. We observed that ET-1 dose dependently increased DNA synthesis of pulmonary artery smooth muscle cells (PASMC), SNP, a NO generating drug, inhibited DNA synthesis of PASMC and its inhibitory effect was mediated by cGMP. Hypoxia increased the proliferative response of PASMS to ET-1 by stimulating autocrine of PASMC and decreased the inhibitory effect of SNP by reducing the activity of intra-cellular soluble guanylate cyclase. Based on the result, it is suggested that the balance of ET-1 and NO and regulation of hypoxia play important roles in hypoxic pulmonary vascular remodeling.

[Preliminary studies on the effects of tumor necrosis factor gene transfer on the growth of human hepatocellular carcinoma cells in nude mice]

An eukaryotic expression vector containing tumor necrosis factor alpha (TNF alpha) gene (psVK3-tnf) was transduced into hepatocellular carcinoma (HCC) cell line, SMMC7721, by calcium phosphate coprecipation method. The TNF-gene-transduced SMMC7721 cell began to secrete TNF after 24h (50 0/ml), reached peak level at 48-72h (90U/ml), and declined after 96h (40U/ml). Three weeks after the pSVK3-tnf DNA entrapped with calcium phosphate was introduced directly into subcutaneous nodules of human HCC in nude mice (treated mice), the growth of HCC was significantly delayed as compared to the pSVK3 group (control mice) (2.5 +/- 1.6 cm vs. 3.2 +/- 1.8 cm, n = 6, P < 0.05). There was a transient increase in TNF alpha level in peripheral blood in the treated but not in the control mice. The survival time of the treated mice was markedly prolonged as compared to the control (44.0 +/- 3.3d vs. 28.2 +/- 2.0d, n = 6, P < 0.01). The above results suggest that TNF alpha gene transfer might be a hopeful therapy for HCC.

p21ras independent down-regulation of ras-induced increases in natural antibody binding during tumor progression

Selective outgrowth of v-H-ras-infected 10T1/2 cells based on the cointroduction of a gene for resistance to geneticin (G418), yielded cells which exhibited an increased capacity to bind polyclonal serum natural antibody (NAb). This demonstrated an NAb-susceptible phase of tumor development which would be a basic requirement for NAb-mediated surveillance of tumors. The ras-oncogene dependence of the high-NAb-binding phenotype provided a model for assessing NAb resistance against ras transformants in vivo and for a comparative analysis of phenotypic and genetic alterations contributing to the progression of ras transformants. Variants were developed through in vitro and in vivo models of tumor progression. T24-H-ras and v-H-ras transformants were isolated in vitro through more rigorous growth conditions, focus formation in the presence of untransformed cells with no selecting drug. These clones expressed p21ras but exhibited little or no increase in NAb binding. Variants recovered following growth from intravenous or threshold subcutaneous (s.c.) inocula of high-NAb-binding ras transformants in syngeneic C3H/HeN mice exhibited decreases in NAb binding but no uniform change in p21ras. Concurring inverse correlations between NAb binding and s.c. tumorigenicity were exhibited by the T24-H-ras transformant clones, the ras transformants grown in vivo, and the v-H-ras-transformed clones isolated in the presence versus the absence of untransformed cells. This consistent inverse correlation, together with the reduced NAb binding of the ras transformants grown in vivo, provides strong evidence that NAb participates in the defense against ras-transformed cells in vivo. The lack of any direct correlation between p21ras expression and the reduction in NAb binding or the increase in tumorigenicity of cells generated through progression in vivo suggested the regulatory action of additional genes. Hybridization studies between high- and low-NAb-binding clones implicated the activation of an additional oncogene and inactivation of an antioncogene in the down-regulation of the ras-induced increases in NAb binding associated with tumor progression.

Isotopic analyses of nitrogenous compounds from the Murchison meteorite: ammonia, amines, amino acids, and polar hydrocarbons

The combined volatile bases (ammonia, aliphatic amines, and possibly other bases), ammonia, amino acids, and polar hydrocarbons were prepared from the Murchison meteorite for isotopic analyses. The volatile bases were obtained by cryogenic transfer after acid-hydrolysis of a hot-water extract and analyzed by combined gas chromatography-mass spectrometry of pentafluoropropionyl derivatives. The aliphatic amines present in this preparation comprise a mixture that includes both primary and secondary isomers through C5 at a total concentration of > or = 100 nmoles g-1. As commonly observed for meteoritic organic compounds, almost all isomers through C5 are present, and the concentrations within homologous series decrease with increasing chain length. Ammonia was chromatographically separated from the other volatile bases and found at a concentration of 1.1-1.3 micromoles g-1 meteorite. The ammonia analyzed includes contributions from ammonium salts and the hydrolysis of extractable organic compounds, e.g., carboxamides. Stable isotope analyses showed the volatile bases to be substantially enriched in the heavier isotopes, relative to comparable terrestrial compounds delta D < or = +1221%; delta 13C = +22%; delta 15N = +93%). Ammonia, per se, was found to have a somewhat lower delta 15N value (+69%) than the total volatile bases; consequently, a higher delta 15N (>93%) can be inferred for the other bases, which include the amines. Solvent-extractable polar hydrocarbons obtained separately were found to be enriched in 15N (delta 15N = +104%). Total amino acids, prepared from a hydrolyzed hot-water extract by cation exchange chromatography, gave a delta 15N of +94%, a value in good agreement with that obtained previously. Nitrogen isotopic data are also given for amino acid fractions separated chromatographically. The delta 15N values of the Murchison soluble organic compounds analyzed to date fall within a rather narrow range (delta 15N = +94 +/- 8%), an observation consistent with their formation, or formation of their precursors, by interstellar chemistry.

Climatic Implications of an 8000-Year Hydrogen Isotope Time Series from Bristlecone Pine Trees

Tree rings from three dendrochronologically dated bristlecone pines were analyzed for stable hydrogen isotopic composition. These trees give a continuous time series from 8000 years ago to the present that indicates the presence of a postglacial climate optimum 6800 years ago and a continuous cooling since then. The qualitative agreement between this record and records from other sources, such as ice cores, pollen, and treeline fluctuations, indicates that these climate changes were global. This record can serve as a reference for other climate indicators throughout the past 8000 years.

p53 gene mutations in pontine gliomas of juvenile onset

Using polymerase chain reaction-single strand polymorphism(PCR-SSCP) and nucleotide analyses, p53 gene mutation was examined in 13 pontine gliomas many of which were of juvenile onset. A total of 15 mutations were detected in 8 cases, of which 5 revealed multiple or tandem mutations. The mutations included 6 G:C-A:T and 4 A:T-G:C transitions and 4 G:C-T:A and 1 A:T-T:A transversions. There was only 1 transition at the CpG site. Normal tissues of the same patients revealed no mutation, suggesting that these mutations were somatic, but not of germ line, in nature. The pattern of mutation characterized by frequent multiple or tandem occurrence, predominancy of transition at non-CpG sites and relatively frequent transversions suggested that pontine glioma might be related with some mutagenic or carcinogenic agents.

Sideband suppression in magic-angle-spinning NMR by a sequence of 5 pi pulses

We report a symmetrical sequence of 5 pi pulses for total sideband suppression in magic-angle-spinning NMR. The sequence is almost evenly spaced and shorter than previous 4 and 6 pi pulse methods.

Neuron-specific enolase (NSE) and non-neuronal enolase (NNE) mRNAs are co-expressed in neurons of the rat cerebellum: in situ hybridization histochemistry

Using in situ hybridization histochemistry, we analysed the localization of mRNAs for neuron-specific enolase (NSE) and non-neuronal enolase (NNE) in the rat cerebellum at various postnatal developmental stages. Synthetic 45 meric oligonucleotides corresponding to partial sequences of the non-coding region of rat NSE or NNE mRNA were 35S-labeled to approximately the same specific activity and used as hybridization probes. On examination of the adult rat cerebellum, both NSE and NNE signals were detected in all identified and presumed neurons which included Purkinje cells, internal granule cells and presumed stellate/basket cells in the cerebellar cortex and neurons of the dentate nucleus. Examination of the cerebellum during postnatal development also revealed coexistence of NSE and NNE signals in these neurons from early stages. During development, both signals coincidentally increased in Purkinje cells and neurons of the dentate nucleus, while only NSE signals showed a gradual increase in the internal granule cells in which NNE signals remained at the same level from early postnatal to adult stages. The external granule cells showed NNE signals until postnatal day 7 but thereafter the signals became less distinct, especially in cells if the inner zone of the external granule cell layer. Thus, it was shown that NSE and NNE were commonly coexpressed at the mRNA level in various neurons of the cerebellum except for very undifferentiated external granule cells which expressed only NNE mRNA.