Arg-Gly-Asp peptide increases endothelial hydraulic conductivity: comparison with thrombin response

The contribution of integrin receptors to the regulation of endothelial permeability was studied using cultured bovine pulmonary microvascular endothelial cell (BPMVEC) monolayers by the measurement of hydraulic conductivity (Lp). Treatment of monolayers with a peptide containing the sequence Gly-Arg-Gly-Asp-Ser-Pro (GRGDSP) (0.85 mM) to compete for the RGD sequence of extracellular matrix (ECM) proteins increased endothelial Lp threefold, whereas the control peptide Gly-Arg-Gly-Glu-Ser-Pro had no effect on Lp. This action of GRGDSP on Lp was not significantly altered by dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP; 0.5 mM). Endothelial Lp increased twofold when the monolayers were challenged with alpha-thrombin (5 x 10(-8) M for 10 min), and this response was completely reversed by DBcAMP. The strength of adhesion of endothelial cells was estimated by evaluating the ability of endothelial cells to remain attached to ECM after treating the monolayers with 0.05% trypsin plus 0.5 mM EDTA. Exposure of the monolayers to either GRGDSP or alpha-thrombin significantly reduced the strength of adhesion to the ECM. DBcAMP prevented the antiadhesive effect of alpha-thrombin but not that of GRGDSP. Treatment of the monolayers with either alpha-thrombin or GRGDSP caused formation of intercellular gaps, but only the thrombin-induced intercellular gaps were accompanied by reorganization of actin filaments. These results indicate that integrin binding to ECM proteins regulates an important determinant of endothelial permeability and that alpha-thrombin and GRGDSP increase endothelial cell monolayer permeability by different mechanisms.

Age estimation on the female sternum by quantification theory I and stepwise regression analysis

One hundred and nine sternums from Chinese females aged 18-50 years were examined in this study. Six morphological characteristics and their changing degree in the female sternum were observed and scored. The data were statistically processed by quantification theory I and stepwise regression analysis on a computer and the following regression equation for age estimation of the female sternum was calculated: y = 19.28 + 1.83x1 + 1.66x2 + 3.02x3 + 1.57x4 + 3.02x5 + 7.75x6 + 1.25x7 + 3.45x8 + 4.88x9 + 0.82x10 + 2.76x11 + 2.48x12 + 7.84x13 + 1.26x14 + 3.80x15 (the correlation coefficient R = 0.9774, the standard deviation S = 2.20, F > 0.01). For convenience, the changing degree of the morphological characters and the equation were also converted into two tables. This method of age estimation on the female sternum is simple and accurate and is of importance to forensic medicine and anthropology.

[Constituents of lignanoids in Siphonostegia chinensis Benth]

A trace monomeric compound was isolated from the aerial part of Siphonostegia chinensis, and determined by X-ray diffraction as a lignanoid compound named syringaresinol. It is obtained from this plant as well as from Scrophulariaceae for the first time.

Glutamine metabolism in chick enterocytes: absence of pyrroline-5-carboxylase synthase and citrulline synthesis

This study was designed to determine whether pyrroline-5-carboxylate (P-5-C) synthase is deficient in chick enterocytes therefore resulting in the lack of synthesis of ornithine and citrulline from glutamine. Post-weaning pig enterocytes, which are known to contain P-5-C synthase and to synthesize both ornithine and citrulline from glutamine, were used as positive controls. Enterocytes were incubated at 37 degrees C for 0-30 min in the presence of 2 mM [U-14C]glutamine or 2 mM ornithine plus 2 mM NH4Cl. In chick enterocytes, glutamine was metabolized to NH3, CO2, glutamate, alanine and aspartate, but not to ornithine, citrulline, arginine or proline. Likewise, there was no formation of citrulline, arginine, alanine or aspartate from ornithine in chick enterocytes. Furthermore, the rate of conversion of ornithine into proline in chick enterocytes was only about 4% of that in cells from pigs. To elucidate the reason for the inability of chick enterocytes to synthesize ornithine and citrulline from glutamine, the activities of the enzymes involved were measured. No activity of P-5-C synthase or ornithine carbamoyltransferase was found in chick enterocytes, in contrast with cells from post-weaning pigs. It was also demonstrated that the activity of ornithine aminotransferase in chick enterocytes was only 3% of that in cells from pigs. Thus the present findings elucidate the biochemical reason for the lack of endogenous synthesis of ornithine and citrulline in chicks. Our results also explain previous observations that ornithine cannot replace arginine or proline in the diet of chicks. We suggest that the absence of P-5-C synthase and ornithine carbamoyltransferase in enterocytes is the metabolic basis for the nutritional requirement of arginine in the chick.

Glutamine and glucose metabolism in enterocytes of the neonatal pig

Glutamine and glucose metabolism was studied in 0- to 21-day-old pig enterocytes. Cells were incubated at 37 degrees C for 30 min in Krebs-Henseleit bicarbonate buffer (pH 7.4) in the presence of 2 mM [U-14C]glutamine with or without 5 mM glucose, or 5 mM [U-14C]glucose with or without 2 mM glutamine. Glutamine was metabolized to ammonia, glutamate, alanine, aspartate, CO2, citrulline, ornithine, and proline, whereas glucose was converted to lactate, pyruvate, and CO2 in pig enterocytes. CO2 production from glutamine accounted for 32-36% and 3-4% of utilized glutamine carbons in 0- to 7-day-old and 14- to 21-day-old pigs, respectively. The rates of O2 consumption and metabolism of glutamine and glucose decreased in enterocytes from 2- to 14-day-old pigs compared with 0-day-old pigs. By day 14 after birth, the oxidation of glutamine and glucose as well as citrulline production had decreased by 90-95%. Arginine synthesis from glutamine occurred in cells from 0- to 7-day-old pigs but not 14- to 21-day-old ones. Glucose (5 mM) had no effect on glutamine utilization and oxidation or the production of glutamate and arginine but stimulated the formation of alanine, citrulline, and proline at the expense of aspartate. In contrast, glutamine (2 mM) inhibited glycolysis and glucose oxidation in cells from 0- to 7-day-old pigs and had no effects in 14- to 21-day-old pigs. As a result, glutamine contributed approximately 2-fold greater amounts of ATP to 0- to 7-day-old pig enterocytes than glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

Cytosine 73 is a discriminator nucleotide in vivo for histidyl-tRNA in Escherichia coli

The acceptor helix of histidine tRNAs in Escherichia coli is capped by a unique base pair in which the cytosine at the discriminator position is paired with an extra guanosine at -1. In previous in vitro studies, the presence of the G-1:C73 base pair was found to be required to obtain both optimal histidylation by histidyl-tRNA synthetase and accurate 5' processing by RNase P. We investigated the role of G-1:C73 in histidine tRNA identity and found that nucleotide substitutions conferred mischarging by other amino acids in a pattern that correlated with the discriminator base and not with the extra nucleotide at -1. As shown by primer extension experiments, the relatively minor role of the -1 nucleotide in vivo could be attributed to altered RNase P processing. These studies show that interactions of tRNAs in vivo both with RNase P during tRNA biosynthesis and with the pool of aminoacyl-tRNA synthetases can modulate the effects of substitutions at recognition nucleotides, eliciting changes in transfer RNA identity.

Identification of allelopathy in the USDA-ARS rice germplasm collection

Field experiments in 1988 and 1989 identified rice accessions from the USDA-ARS rice germplasm collection for allelopathic effects to ducksalad [Heteranthera limosa (Sw.) Willd.]. About 10000 accessions were evaluated; 347 accessions had apparent allelopathic activity. Accessions that had demonstrated allelopathic activity to ducksalad in 1988 or 1989 were evaluated further for allelopathic activity in 1990 (67 accessions) and 1991 (47 accessions). In 1990, 12 accessions had a radius of activity of 0.18-0.20 m and 80-90% weed control within the area of activity. In 1991, 12 different accessions had a radius of activity of 0.13-0.18 m and 50-85% weed control in the area of activity.

A multidrug resistance regulatory chromosomal locus is widespread among enteric bacteria

Constitutive expression of the mar operon (marRAB) in Escherichia coli produces a multiple antibiotic resistance phenotype mediated by the expression of multiple genetic loci in response to regulatory proteins in the operon. A mar-specific DNA probe was used to search for the operon in bacterial strains representing 53 species and 27 genera. Among these, 6 other Enterobacteriaceae, Salmonella, Shigella, Klebsiella, Citrobacter, Hafnia, and Enterobacter species, contained DNA sequences that hybridized to the probe under high-stringency conditions. By use of a selection protocol developed to obtain multiple antibiotic resistant mutants of E. coli, multiply resistant mutants that showed increased expression of mar-specific RNA were obtained from Enterobacter agglomerans and Salmonella species.

Variation of Cmax and Cmax/AUC in investigations of bioequivalence

In order to enable the setting of regulatory criteria for the equivalence of absorption rates on a sound scientific basis, the variation of Cmax/AUC and Cmax was evaluated. Under most conditions, the variation of Cmax/AUC was 10-25% higher than that of AUC independently of the variability of the extent of absorption. By contrast, the variation of Cmax was 50-60% higher than that of AUC and was strongly dependent on the variability of the extent of absorption. Therefore, it is recommended that for establishing the equivalence of absorption rates, the 90% confidence limits for the percentage ratio of the Cmax/AUC values of two drug products should be (based on their logarithmic averages or medians) between 75 and 133%. Regulatory decisions based on Cmax, while not favored, should expect that the 90% confidence limits for the percentage ratio of the Cmax values of two drug products be (based on their logarithmic averages or medians) between 70 and 143%. These recommendations parallel and are contingent upon the internationally harmonized criterion for the equivalence of extents of absorption which requires that the 90% confidence limits for the percentage ratio of two AUC values (based on their logarithmic averages or medians) be between 80 and 125%.

Effects of hyaluronic acid on the release of proteoglycan from the cell matrix in rabbit chondrocyte cultures in the presence and absence of cytokines

OBJECTIVE

To investigate the effects of hyaluronic acid (HA) on the release of proteoglycan by cultured rabbit chondrocytes.

METHODS

Articular cartilage chondrocytes were isolated from the knee joints of New Zealand white rabbits. Proteoglycan synthesis after incubation with HA was determined by measuring 35S-sulfate incorporation. Cells incubated with HA were labeled with 3H-glucosamine and applied to a Sepharose CL-2B column. After incubation of confluent cells with 35S-sulfate and then with HA in various concentrations in the presence or absence of cytokines, proteoglycan release from the cell matrix layer was measured.

RESULTS

HA (M(r) 3 x 10(5) to 19 x 10(5)), at 10 micrograms/ml to 1 mg/ml, had little effect on the incorporation of 35S-sulfate or 3H-glucosamine into cartilage matrix proteoglycans, or on the hydrodynamic size of proteoglycan monomers, in rabbit chondrocyte cultures. However, at 10-1,000 micrograms/ml, HA suppressed the release of 35S-proteoglycans from the cell matrix layer into the medium in the presence and absence of interleukin-1, tumor necrosis factor alpha, or basic fibroblast growth factor.

CONCLUSION

These results suggest that HA is a potent inhibitor of the displacement of matrix proteoglycan into culture medium.

The interferon-induced double-stranded RNA-activated human p68 protein kinase potently inhibits protein synthesis in cultured cells

The role of the interferon-induced double-stranded RNA (dsRNA)-activated human p68 protein kinase as an inhibitor of protein synthesis has been inferred from work with cell-free systems, but direct proof in animal cells is lacking. To document the action of p68 protein kinase in vivo, we have used an infection-transfection system where expression of p68 is driven by a vaccinia virus promoter regulated by the lacl repressor/operator controlling elements. In cultured cells infected with vaccinia virus and transfected with a plasmid containing the p68 gene, there is synthesis of p68 when lacl repressor is inhibited with isopropyl-beta-D-thiogalactoside. When infection-transfections are carried out with the p68 gene together with the luciferase (LUC) reporter gene, a strong inhibition of LUC expression developed with time postinfection. This inhibition was not observed with a mutant form of the kinase (Lys-->Arg at position 296) and it was reversed by antisense expression of the p68 gene. During inhibition of LUC expression the protein kinase was phosphorylated, possibly as a result of autophosphorylation activated by the dsRNA forms which are known to accumulate in vaccinia virus-infected cells. Inhibition of LUC expression was at the level of translation. Our findings demonstrate that expression and activation of the human p68 protein kinase in vivo potently inhibits protein synthesis.

Localization of juvenile, but not late-infantile, neuronal ceroid lipofuscinosis on chromosome 16

The neuronal ceroid lipofuscinoses (NCL) are a group of progressive neurodegenerative disorders characterized by the deposition of autofluorescent proteinaceous fingerprint or curvilinear bodies. We have found that CLN3, the gene underlying the juvenile form of NCL, is very tightly linked to the dinucleotide repeat marker D16S285 on chromosome 16. Integration of D16S285 into the genetic map of chromosome 16 by using the Centre d'Etude du Polymorphisme Humain panel of reference pedigrees yielded a favored marker order in the CLN3 region of qtel-D16S150-.08-D16S285-.04-D16S148-.02-D16S 67-ptel. The most likely location of the disease gene, near D16S285 in the D16S150-D16S148 interval, was favored by odds of greater than 10(4):1 over the adjacent D16S148-D16S67 interval, which was recently reported as the minimum candidate region. Analysis of D16S285 in pedigrees with late-infantile NCL virtually excluded the CLN3 region, suggesting that these two forms of NCL are genetically distinct.

Detection of circulating antigen by McAb-AST for evaluating the efficacy of anti-Leishmania chemotherapy

We have adapted the simple and sensitive McAb-antigen spot test (AST) for evaluating the efficacy of anti-Leishmania chemotherapy. Serum samples from 37 kala-azar patients were tested by McAb-AST, and all showed definite positive reactions before treatment. After a course of antimony treatment, 20 turned negative, coupled with the disappearance of clinical symptoms; another 12 cases responded with weak positivity accompanied by an improvement of clinical manifestations; and the remaining 5 antimony-resistant patients showed strong positive reactions, with their conditions gradually worsening. Furthermore, all 6 cases in which the diagnosis was missed by the bone marrow smear method turned McAb-AST negative after chemotherapy. These results suggest that McAb-AST can be used to evaluate the efficacy of chemotherapy as well as to avoid missed diagnosis by the bone marrow smear method.

Hormonal profile of the menstrual cycle in Chinese women after tubal sterilization

Ten women after tubal sterilization were studied for the hormonal profile of the menstrual cycle. They had undergone sterilization procedures, on the average 5.3 years (range 1.5-10 years) earlier. The serum concentrations of LH, FSH, prolactin, estradiol and progesterone were measured by RIA in daily blood samples of a complete menstrual cycle. Another ten normal women were studied at the same time and were used as the control group. There were no significant differences in the hormonal patterns of the menstrual cycle between the two groups. There was a significantly lower LH level in the early luteal phase of the tubal ligation group compared to the control group. Also, a significantly lower E2 luteal peak compared to the preovulatory peak was observed in the tubal ligation group. The physiological significance of these minor changes is not clear. Only one out of ten women in the tubal ligation group, who had undergone sterilization 1.5 years prior, showed a deficiency in luteal function, but her ovulatory function and menstrual cycle appeared normal. This study indicates that normal hormonal profiles are retained after tubal sterilization.

Genome maps of Campylobacter jejuni and Campylobacter coli

Little information concerning the genome of either Campylobacter jejuni or Campylobacter coli is available. Therefore, we constructed genomic maps of C. jejuni UA580 and C. coli UA417 by using pulsed-field gel electrophoresis. The genome sizes of C. jejuni and C. coli strains are approximately 1.7 Mb, as determined by SalI and SmaI digestion (N. Chang and D. E. Taylor, J. Bacteriol. 172:5211-5217, 1990). The genomes of both species are represented by single circular DNA molecules, and maps were constructed by partial restriction digestion and hybridization of DNA fragments extracted from low-melting-point agarose gels. Homologous DNA probes, encoding the flaAB and 16S rRNA genes, as well as heterologous DNA probes from Escherichia coli, Bacillus subtilis, and Haemophilus influenzae, were used to identify the locations of particular genes. C. jejuni and C. coli contain three copies of the 16S and 23S rRNA genes. However, they are not located together within an operon but show a distinct split in at least two of their three copies. The positions of various housekeeping genes in both C. jejuni UA580 and C. coli UA417 have been determined, and there appears to be some conservation of gene arrangement between the two species.

[Cloning and orientation of a promoter of thermophilic Thiobacillus sp]

Thiobacillus sp. is an obligate autotrophic thermophilic bacterium which was isolated from an acidic hot spring in Yunnan Province. Its optimum growth temperature is 45-50 degrees C and its optimum pH is 2.0-3.0. Using DNA recombinant technique, we inserted the HindIII fragments of the Thiobacillus sp. chromosomal DNA into the HindIII site of promoter-probe plasmid pSDSI (AprTcs, 5.65 kb). Transformants resistant to tetracycline were obtained on Tc plates (12 micrograms/ml). Of these, twenty transformants were able to grow on 120 micrograms/ml Tc plates, and two of them, designated pSDH7 and pSDH11, were able to grow on plates containing Tc at concentration up to 360 micrograms/ml. With HindIII, pSDH11 produced a 0.95kb fragment which had the function of promoter and a PstI site besides the 5.65 kb fragment of pSDSI. Southern blot hybridization showed that the 0.95 kb insert was from the Thiobacillus sp. chromosomal DNA. After restriction mapping, a 2.85 kb fragment of pSDH11 (which contained 0.7 kb of the inserted fragment) was removed with the aid of Pst1, and the remained fragment was used to construct a 3.75 kb plasmid (named pSDH114) which was resistant to a higher level of tetracycline (360 micrograms/ml) than for pBR322 (120 micrograms/ml). The remained 0.25 kb foreign fragment in pSDH114 still retained full function of the promoter contained in the original 0.95 kb. Thus we could orient the cloned promotor function fragment (0.25 kb) from Thiobacillus sp. in pSDH114.

Characterization of erythromycin resistance in Campylobacter jejuni and Campylobacter coli

The mechanism of resistance to erythromycin, the drug of choice in the treatment of campylobacter gastroenteritis, was investigated. Erythromycin resistance (MICs, greater than 1,024 micrograms/ml) in three clinical isolates of Campylobacter jejuni and one C. coli isolate was determined to be constitutive and chromosomally mediated. In vivo protein synthesis in erythromycin-susceptible C. jejuni and C. coli strains was completely inhibited by low levels of erythromycin (5 micrograms/ml), whereas a high concentration of the antibiotic (100 micrograms/ml) had no effect on protein synthesis in erythromycin-resistant strains. Biological assays showed that extracellular degradation of erythromycin was not responsible for erythromycin resistance in strains of Campylobacter species. The rates and amounts of uptake of [14C]erythromycin by resistant and susceptible campylobacter cells were determined to be similar. Binding assays with purified campylobacter 70S ribosomes as well as 50S ribosomal subunits showed that those from erythromycin-resistant strans bound much less [14C]erythromycin than did those from susceptible strains. Genomic DNA from C. coli UA585 was used to transform erythromycin resistance to C. coli UA417. The erythromycin resistance marker was associated with a 240-kb SmaI fragment of the C. coli UA585 genome. Our results rule out erythromycin inactivation or efflux and are not consistent with the production of an RNA methylase, although they are consistent with a mutational mechanism of resistance due to a change in a ribosomal protein gene. This study constitutes a detailed biochemical and genetic characterization of erythromycin resistance in Campylobacter species.

[Autologous bone marrow transplantation in acute myeloid leukemias: a report of 7 cases]

Seven patients with acute myeloid leukemias (AML) in complete remission (CR) were treated with high dose chemotherapy and/or total body irradiation (TBI) followed by autologous bone marrow transplantation (ABMT). The clinical status of the 7 cases at ABMT were as follows: 5 in CR1 (2 with standard risks and 3 with high risks) and 2 in CR2 (both with standard risks). The conditioning regimens used for ABMT were cyclophosphamide plus TBI in 3 cases, high dose busulfan plus cyclophosphamide in 3 cases, and BACT program chemotherapy in 1 case. All 7 cases showed hemopoietic reconstitution after ABMT; no death occurred within the post-transplantation aplasia period, but hepatotoxicity was observed with high dose busulfan. Up to December, 1989, 2 patients in CR1 with standard risk receiving transplants had survived, disease free, for 26 and 18 months, respectively; one of 2 patients in CR2 with standard risk receiving transplants had survived for 30 months, and the other died at the 9th month after ABMT with no sign of leukemia relapse. Two of the 3 patients with high risk relapsed at 5 months post-ABMT and the third was in continuous CR for 5.5 months.

Cmax/AUC is a clearer measure than Cmax for absorption rates in investigations of bioequivalence

In bioequivalence studies, the maximum concentration (Cmax) is shown to reflect not only the rate but also the extent of absorption. Cmax is highly correlated with the area under the curve (AUC) contrasting blood concentration with time. Therefore, use of the Cmax/AUC ratio is recommended for assessing the equivalence of absorption rates. The ratio is independent of both intrasubject variations and possible differences in the extent of absorption and reflects only the contrast between the absorption and disposition rate constants (ka/k).

Sizing and mapping of the genome of Campylobacter coli strain UA417R using pulsed-field gel electrophoresis

Agarose-immobilized chromosomal DNA from the nalidixic-acid-resistant Campylobacter coli strain UA417 and its streptomycin-resistant (StrR) derivative, UA417R, were digested with the restriction enzymes SalI (GTCGAC) and SmaI (CCCGGG). The sizes of the resulting fragments were determined using pulsed-field gel electrophoresis. The two genomes showed similar restriction patterns of seven and 13 fragments for the two respective enzymes and the total genome size was determined to be approx. 1.7 Mb. Analysis of partial digestion fragments, as well as Southern-blot hybridization, were used to construct a physical map of the C. coli UA417R genome. Natural transformation studies using DNA fragments extracted from UA417R, as well as the erythromycin-resistant (EryR) C. coli strain UA585, were used to locate the StrR and EryR resistance markers on the genomic map.

Pulsed-field gel electrophoresis of Campylobacter jejuni and Campylobacter coli genomic DNA and its epidemiologic application

Genomic DNA from 12 different Campylobacter jejuni and 10 Campylobacter coli isolates was digested with SmaI and analyzed by pulsed-field gel electrophoresis (PFGE) and 16S rRNA hybridization studies. Although the two Campylobacter species displayed species-specific restriction and hybridization patterns, significant intraspecies differences were observed. Combined PFGE and hybridization pattern analysis failed to provide any more epidemiologic information than was obtained from PFGE restriction profiles alone. Therefore, results from these studies indicate that PFGE analysis of SmaI-restricted genomic DNA provides a reliable means of differentiating C. jejuni from C. coli and may represent a more practical approach to epidemiologic studies than combining conventional DNA restriction digestion pattern with RNA hybridization procedures.

[Original botanical statistics and commercial study of the Chinese drug touguchao]

According to original botanical statistics, there are 42 species and 5 varieties belonging to 20 families called or used as Touguchao. Commercial investigation shows that 16 species belonging to 12 families are presently available on the market in China.