The relationship between gastric mucosal changes and nitrate intake via drinking water in a high-risk population for gastric cancer in Moping county, China

There are conflicting reports on whether nitrate intake is related to gastric carcinogenesis. In this laboratory/field study from a high-risk area for gastric cancer, we analysed 178 samples of drinking water for nitrate and nitrite, and examined the relationship between gastric mucosal lesions (including gastric cancer) and quality of different types of drinking water and nitrate intake via water. The results showed that the nitrate content in the local drinking water was generally very high, with a mean of 109.6 mg/l (range 4.4-497.2 mg/l). There were significant differences in the nitrate content in drinking water from different wells in qualitatively different types of water. The histological changes were closely related to the quality of drinking water and its nitrate content. The results suggest that nitrate in drinking water probably plays an important role in gastric carcinogenesis and that in future aetiological studies of gastric cancer should include more information on well depth, the presence of public or private wells and nitrate content of water.

Tissue-specific expression of a rat intestinal mucin-like peptide

Expression of the gene for a rat intestinal mucin-like peptide (MLP) was studied by Northern-blot analyses of RNA prepared from a panel of rat tissues. Four probes (A-D) were constructed so as to span a 3.5 kb-long cDNA for rat MLP, and used for hybridization. Positive signals were obtained in intestine and colon, whereas lung, liver, stomach, submandibular gland and spleen were negative. The only transcript detected was approx. 9.5 kb in size. No mRNA splice variants were found. Hybridization in situ using probe B1, which corresponds to a cysteine-rich region near the C-terminus of MLP, confirmed that the gene for MLP is expressed by goblet cells of rat intestine and colon.

A serine, threonine and proline-rich region near the carboxyl-terminus of a rat intestinal mucin peptide

Further sequencing of a cDNA encoding the C-terminal region of a rat intestinal mucin peptide reveals a region corresponding to 258 amino acids enriched in serine, threonine and proline, but no typical mucin-like tandem repeat structures. Between this region and a previously described stretch of 4.5 degenerate S,T,P-rich tandem repeats, there is a 42 amino acid cysteine-rich segment. The discontinuity of cysteine-rich and S,T,P-rich areas near the C-terminus has not been observed in other mammalian mucin structures reported to date.

Protein synthesis during germination of heterothallic yeast ascospores

Protein synthesis during ascospore germination of the heterothallic Saccharomyces cerevisiae strain AP-3 was investigated. Protein synthesis in the germinating ascospores appeared to begin approximately 20 min following glucose initiation. Since RNA synthesis did not start until approximately 70 min after the onset of germination, strain AP-3 ascospores must contain RNA which is ready for immediate translation. Both trehalase and glyceraldehyde-3-phosphate dehydrogenase activities were found to be affected by the onset of germination. Trehalase activity was found to increase severalfold following 60 min of spore germination but remained relatively constant over the subsequent 120 min examined. Dehydrogenase activity was not detectable in AP-3 ascospores but was measurable in germinating ascospores.

[Textual study on traditional Chinese drugs caodoukou and baidoukou]

Through a critical study of herbalogy, it is concluded that the mature seeds of Alpinia zermubet were used as caodoukou in ancient times. The original plant of Yutao recorded in Zhiwu Mingshi Tukao may be the species of Alpinia katsumadai. Baidukou used in ancient times may be the seeds of Alpinia katsumadai found in the south of China, or Amomum compactum and Am. kravanh imported from foreign countries.

Characterization of human adenylate kinase 3 (AK3) cDNA and mapping of the AK3 pseudogene to an intron of the NF1 gene

We have isolated cDNA clones for human adenylate kinase isozyme 3 (AK3) with a genomic probe from the neurofibromatosis type 1 (NF1) region. Three overlapping clones isolated from a human frontal-cortex cDNA library gave rise to a consensus sequence of 1.7 kb. The open reading frame identified in this sequence predicted a peptide of 223 residues. A database search revealed striking homology, about 58% amino acid sequence identity, between this predicted protein and bovine AK3. Human AK3 protein also showed significant homology to other members of the adenylate kinase family isolated from various species. Genomic Southern analysis suggested that multiple AK3 loci exist in the human genome, including one located in an intron of NF1 on chromosome 17. The chromosome-17 locus appears to be a processed pseudogene, since it is intronless and contains a polyadenylate tract; it nevertheless retains coding potential because the open reading frame is not impaired by any observed base substitutions.

[Macrological identification of Chinese drug dangshen (radix Codonopsis)]

Macrological characters of 17 reference crude drugs from Codonopsis and Campanumoea were observed. Identification of 110 samples collected from 18 provinces of China indicated that more than 70 percent of the commercial Dangshen is derived from Codonopsis pilosula.

Structural determination of gangliosides that bind to influenza A, B, and C viruses by an improved binding assay: strain-specific receptor epitopes in sialo-sugar chains

An improved binding assay for detection of ganglioside receptors for influenza A, B, and C viruses was developed. In this system, the virions bound to gangliosides that were developed on a silica gel thin-layer plate were detected by mouse monoclonal antibody against viral hemagglutinin and peroxidase-conjugated anti-mouse immunoglobin. No hydrolysis of the gangliosides by viral receptor-destroying enzyme was detected in the present condition. The reactivity of the viruses to gangliosides depended on the amount of developed gangliosides (10 pmols-10 nmols), the molecular species of sialic acid, and their sugar sequences. Human influenza A (PR/8/34), B (Lee/40), and C (Ann Arbor/1/50) viruses bound different receptor epitopes of sialo-sugar chains of gangliosides. The A/PR/8 virus bound most effectively to Neu5Ac-containing lacto-series gangliosides carrying type I and type II sugar chains, followed by ganglio-series and hematoside-series gangliosides. The A/PR/8 virus weakly bound to Neu5Ac alpha 2,6lactotetraosylceramide [IV6(Neu5Ac)Lc4Cer] and Neu5Ac alpha 2,6paragloboside [IV6(Neu5Ac)nLc4Cer] carrying Neu5Ac alpha 2,6Gal sequence, although their Neu5Ac alpha 2,3Gal derivatives were the most potent gangliosides tested. B/Lee/40 bound restrictively to IV6(Neu5Ac)Lc4Cer and IV6(Neu5Ac)nLc4Cer, which carry Neu5Ac alpha 2,6Gal sequence, and type I and type II lacto-series sugar chain, respectively. C/Ann Arbor/1/50 reacted only with 9-O-Ac-Neu5Ac-carrying sugar chains in all the gangliosides tested. This method also allowed the microanalysis of receptor gangliosides of unknown samples. ESK cells, sensitive to the influenza A viruses infection, expressed several kinds of receptor active gangliosides, while those from ESK-R cells, resistant to the virus infection, were undetectable.

Signal transduction events whereby PGF2 alpha inhibits the ammoniagenic response to acute acidosis

Subconfluent cultures of LLC-PK1 cells were incubated for 1 h in Krebs-Henseleit buffer (KHB) of pH 7.4 or 6.8 to investigate the signal transduction events associated with prostaglandin F2 alpha (PGF2 alpha) inhibition of ammonia metabolism. Exposure of these cultures to PGF2 alpha (0.1 ng/ml) inhibited the acute low pH stimulation of ammonia production and to a lesser degree alanine formation in a manner analogous to the response exhibited with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Pretreatment with an inhibitor of protein kinase C [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, i.e., H-7] or utilization of cultures with downregulated protein kinase C activity abolished the inhibitory response to PGF2 alpha. Exposure to PGF2 alpha for 10 min in KHB of pH 6.8 resulted in an activation of protein kinase C, as demonstrated by a significant increase in membrane-bound enzyme activity. Incubation of the cells with PGF2 alpha in KHB of pH 6.8 also resulted in a significant increase in inositol trisphosphate formation. Treatment of the cultures with verapamil in calcium-containing medium or removal of calcium from the incubating medium resulted in a significant loss of the PGF2 alpha inhibitory response on both ammonia and alanine production. Furthermore, under conditions of calcium-free incubation, PGF2 alpha had no significant effect on protein kinase C activity. Because both PGF2 alpha- and TPA-induced inhibition of ammoniagenic response to acute acidosis was prevented by amiloride, the underlying mechanism may involve protein kinase C-mediated changes in intracellular pH. These results indicate that the activation of protein kinase C plays a key role in mediating PGF2 alpha inhibition of ammoniagenesis.

Glycocholic acid and glycodeoxycholic acid but not glycoursocholic acid inhibit bile acid synthesis in the rabbit

Feedback regulation of derepressed hepatic bile acid biosynthesis was studied individually with glycocholic, glycodeoxycholic, and glycoursocholic acids by infusion into bile acid-depleted rabbits. Construction of a bile fistula drained the endogenous bile acid pool (90% glycodeoxycholic acid, 10% glycocholic acid) within 24 hours and elicited maximal bile acid synthesis after about 72 hours, at which time glycocholic acid became the only biliary bile acid (greater than 98%). Replacement of the bile acid pool with glycocholic acid or glycodeoxycholic acid at a rate equivalent to the hepatic endogenous bile acid flux inhibited endogenous biosynthesis by 40%. In contrast, glycoursocholic acid, the 7 beta-hydroxy epimer of glycocholic acid, failed to suppress synthesis. Hepatic bile acid depletion increased hydroxymethyglutary coenzyme A (HMG-CoA) reductase activity fourfold and cholesterol 7 alpha-hydroxylase activity threefold, which were reduced 48% and 51%, respectively, from their maximum levels during replacement with glycocholic acid. Glycodeoxycholic acid infusion depressed cholesterol 7 alpha-hydroxylase activity by 59% without reducing HMG-CoA reductase activity significantly. There was no significant change in the activity of either enzyme during glycoursocholic acid infusion. Biliary cholesterol and cholestanol secretion declined 13% and 53%, respectively, during glycocholic acid infusion, were not affected by glycodeoxycholic acid infusion, but increased 19% and 43%, respectively, during glycoursocholic acid infusion. These results show that in rabbits the feedback regulation of hepatic bile acid synthesis depends on the hepatic flux of the normally present endogenous bile acids glycocholic acid and glycodeoxycholic acid but does not respond to the 7 beta-hydroxy glycoursocholic acid. Glycocholic acid inhibits both HMG-CoA reductase and cholesterol 7 alpha-hydroxylase while glycodeoxycholic acid affects primarily cholesterol 7 alpha-hydroxylase. Thus, the regulation of bile acid synthesis may be mediated by both the availability of cholesterol substrate and the activity of the rate-determining enzyme for bile acid synthesis.

Human intestinal mucin-like protein (MLP) is homologous with rat MLP in the C-terminal region, and is encoded by a gene on chromosome 11 p 15.5

A cDNA specific for a human intestinal mucin (MLP) was amplified by PCR from cDNA of cultured human colonic adenocarcinoma cells, LS174T. The human cDNA shared high sequence homology with a corresponding rat intestinal mucin (MLP) cDNA in the 3' terminal region, and hybridized to the same mRNA (approximately 9.0 Kb) that was recognized by a probe for the MUC-2 human intestinal mucin gene. The gene encoding our human mucin peptide also mapped to chromosome 11 p 15.5, the known locus of MUC-2. Our findings suggest that human MLP and MUC-2 are encoded by the same gene and that rat and human intestinal mucin share a common C-terminal amino acid structure.

cDNA for the carboxyl-terminal region of a rat intestinal mucin-like peptide

When subjected to thiol reduction, purified intestinal mucins have been shown to undergo a decrease in molecular mass and to liberate a 118-kDa glycopeptide (Roberton, A. M., Mantle, M., Fahim, R. E. F., Specian, R., Bennick, A., Kawagishi, S., Sherman, P., and Forstner, J. F. (1989) Biochem. J. 261, 637-647). The latter has been called a putative "link" component because it is assumed to be important for disulfide bond-mediated mucin polymerization. Controversy exists as to whether the putative link is an integral mucin component or a separate mucin-associated glycopeptide. In the present study both NH2-terminal and internal amino acid sequences of the 118-kDa glycopeptide of rat intestinal mucin were used to generate opposing oligonucleotide primers for polymerase chain reaction. A specific 1.2-kilobase (kb) product was obtained, from which a 0.5-kb HindIII fragment was used as a probe to screen a lambda ZAP II cDNA library of rat intestine. A 2.6-kb cDNA (designated MLP 2677) was sequenced and revealed an open reading frame of 2.5 kb encoding 837 amino acids. The deduced amino acid sequence showed that the putative link peptide is equivalent to the carboxyl-terminal 689 amino acids of a larger peptide. Northern blots revealed a mRNA size of approximately 9 kb. Computer searches revealed no sequence homology with other proteins, but similarities were seen in the alignment of cysteine residues in the link and in several domains of human von Willebrand factor, as well as cysteine-rich areas of bovine and porcine submaxillary mucins and a frog skin mucin designated FIM-B.1. In keeping with earlier demonstrations of the presence of mannose in the 118-kDa glycopeptide, there were several (13) consensus sequences for attachment of N-linked oligosaccharides within the link domain. Further sequencing of MLP 2677 in a direction 5' to the codon specifying the NH2-terminal proline of the link has revealed a coding region for 148 amino acids, including a unique 75-amino acid domain rich in cysteine and proline, and a region containing 4.5-variable tandem repeats (each 11-12 amino acids) rich in serine, threonine, and proline. The presence of mucin-like tandem repeats suggests that the entire cysteine-rich link peptide represents the carboxyl-terminal region (75.5 kDa) of a mucin-like peptide (MLP). The latter is estimated to have a molecular mass of approximately 300 kDa.

[Quality of tuberous root of Liriope spicata (Thunb.) Lour. var. prolifera Y.T.Ma and Ophiopogon japonicus (L.F.) Ker-Gawl.--comparison of immune function]

This paper deals with comparative study on the immune function of the tuberous root of Liriope spicata var. prolifera and Ophiopogon japonicus. The results showed that the aqueous extract of both species mentioned above could increase obviously the spleen weight (immunity organ) of mice, enhance the clearance rate of iv charcoal particles in mice and antagonize remarkably the leukopenia caused by cyclophosphamide.

[Studies on the quality of fructus Cnidii--comparison of antibacterial action]

Comparative studies on antibacterial and antifungal action of the fruits of C. monnieri from four habitats and two other species of Cnidium showed they had inhibitory potency to some bacterial and fungi in vitro. C. monnieri and C. salium were more effective than C. dahuricum in antibacterial activities. C. monnieri had higher antifungal effect than C. salium and C. dahuricum.

[Textual and herbal studies on shashen and qini (Adenophora spp.)]

This paper reports the origins of the Chinese traditional drugs nanshashen and beishashen, as well as the original plants of shashen, xingyeshashen, xiyeshasen and qini recorded in the bencaological works of the past dynasties. Our study shows that shashen is Adenophora stricta, both xingyeshashen and qini are A. hunanensis and xiyeshashen is A. paniculata.

[Survey of an outbreak of mycoplasmal pneumonia firstly discovered in Zhejiang Province]

An exceptional outbreak of mycoplasmal pneumonia in a factory of prisoners, Juzhou city, Zhejiang province, during November to December, 1985 was reported. In the course of the epidemic 102 cases were infected, with an attack rate of 3.3 per cent, but the attack rate in the outbreak point was 29.1 per cent. All cases were not dead. This outbreak was diagnosed as mycoplasmal pneumonia by clinical observation, X ray examination serological test and epidemiological survey. The sources of infection were 3 sporadic patients. The epidemic was quickly controlled by using comprehensive preventive measures.