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H Shang

Publications and source records attributed to H Shang.

29 records · Page 2Linked to original sources
PubMed1995

De novo generation of defective interfering-like RNAs in broad bean mottle bromovirus.

Broad been mottle virus (BBMV) is the only member of the bromoviruses that is known to accumulate defective-interfering (DI) RNAs (Romero et al., Virology 194, 576-584, 1993). De novo generation of DI-like RNAs was demonstrated during serial passages of BBMV in broad bean using either DI RNA-free virion RNA preparations or transcribed genomic RNA inocula. As for previously described DI RNAs, all but one of the characterized de novo generated DI-like RNAs were derived by a single in-frame deletion from the RNA2 component. The sole exception was derived by two shorter in-frame deletions from RNA2. The maintenance of an open reading frame by all DI-like RNAs suggests the importance of coding capacity and/or the shortened 2a protein in the accumulation of these RNAs during infection. The deletion junction sites were between nucleotides 1152 and 2366, suggesting that the retained regions are essential for the efficient accumulation of BBMV DI-like RNAs in planta. Short regions of sequence similarity and/or complementarity were revealed at the 5' and 3' junction borders. We speculate that these regions can facilitate DI (DI-like) RNA formation. In addition to DI-like RNAs, the full-length nucleotide sequences of RNA2 components of the Type and Morocco strains of BBMV are presented.

Amino Acid Sequence↗
PubMed1995

Suppression of HIV-1 reverse transcriptase activity by culture supernatants of mycoplasmas.

Coinfection with mycoplasmas has been shown to enhance cytopathic changes in T lymphocytes in culture brought about by human immunodeficiency virus type-1 (HIV-1), accelerate disease progression, and suppress reverse transcriptase (RT) activity simultaneously. We attempted to identify the components in culture supernatants of mycoplasmas which suppress RT activity. The marked inhibitory effect on RT by culture supernatants was dependent upon Mg2+. The culture supernatants exhibited the activities of DNase and RNase, which degraded the products and substrates in RT assay, respectively. Gel filtration studies revealed that two major protein peaks, peak 1 (MW 67-100 kDa) and peak 2 (MW 10-25 kDa), exhibited DNase and/or RNase activities, and that both peaks contained a significant degree of inhibitory activity on RT. These results indicate that suppression of RT activity by the culture supernatants of mycoplasmas is due to DNase and RNase activities in the culture supernatants. The results of the present investigation suggest that RT assay of certain biological materials that are contaminated with mycoplasmas must be conducted carefully.

Cell Line↗
PubMed1994

Antigen-specific suppression of antibody responses by T lymphocytes cytotoxic for antigen-presenting cells.

In this study we demonstrated an alternative model of the antigen (Ag)-specific suppression of antibody response in mice. Splenocytes that were taken from BALB/c mice immunized by i.v. injection of soluble human serum albumin (HSA) or ovalbumin exhibited MHC-restricted Ag-specific cytotoxicity for the respective antigen-presenting cells (APC). When HSA-primed splenocytes cultured with Ag and interleukin-2 (IL-2) were treated with anti-CD4 or anti-CD8 monoclonal antibody (mAb) plus complement, CD8+ and CD4+ T cells exhibited nearly the same level of cytotoxicity against APC. Furthermore, HSA-primed CD4+ and CD8+ T cells released the same amount of interferon-gamma (IFN-gamma) when stimulated with Ag and IL-2. Recombinant IFN-gamma was shown to suppress the in vitro plaque-forming cell (PFC) response to sheep red blood cells (SRBC) only when it was added within 24 h after addition of Ag. The supernatants from both HSA-primed CD4+ and CD8+ T cells suppressed the PFC response to SRBC in vitro, and the suppressive activity was abrogated by anti-IFN-gamma mAb, but increased by anti-IL 4 mAb. These results suggest that in our system the effector cells for Ag-specific suppression of the antibody response in mice are both the cytotoxic type 1 clones (IFN-gamma-producing) of CD4+ and CD8+ T cells for APC, and that IFN-gamma is a major extracellular effector molecule for such suppression.

Animals↗
PubMed1990

[Mediastinal infection following open heart surgery].

31 cases of mediastinal infection occurred in 7164 patients who had undergone open heart surgery under CPB were reviewed in the period of 1981-1989. The over-all incidence was 0.43%. Analysis of the clinical material showed that mediastinal infection was mostly associated with the following predisposing factors: (1) prolonged CPB time; (2) rethoracotomy; (3) open cardiac massage; (4) tracheostomy; (5) combined severe circulatory or/and respiratory complications. 28 patients were treated by mediastinal debridement and 27 of them were irrigated with 0.5% betadine or/and antibiotic solutions. Debridement was done a second time in 5 patients with smooth recovery. There were 15 deaths (48.4%), of which 4 were caused by rupture of cardiac or aortic incisions, 5 by multisystemic complications and 6 by severe infection. The mortality was significantly higher in the cases with combined circulatory or/and respiratory complications (72.2%) than in the cases of simple mediastinal infection (15.4%).

Adolescent↗
PubMed1988

Gram stain and culture of morning and 24 h sputum in the diagnosis of bacterial exacerbation of chronic bronchitis: a dogma disputed.

Bacteriological results from microscopic and cultural examinations of morning and 24 h sputum were compared in an attempt to optimize the diagnosis of bacterial exacerbations of chronic bronchitis. Twelve patients collected sputum randomly on two consecutive days, either fresh morning sputum (3 h sputum) first, followed by 24 h sputum or vice-versa. Sputa were washed three times in 0.9% NaCl and then examined microscopically before and after homogenization with 2% pancreatin. Cultural examinations were performed on homogenized sputum. Haemophilus influenzae, pneumococci and neisseriae were identified more often in Gram stains than in cultures; staphylococci and Gram-negative rods less frequently so. About 50% of organisms microscopically identified as pneumococci failed to grow in cultures. Microscopic examinations revealed a marked reduction of cells and bacteria after homogenization with pancreatin. Gram stains of 24 h sputum show comparable results to those of morning sputum. No differences were found in cultures. Microscopic examination of the Gram stains was found to be superior to cultural examination. The value of microscopic examination was impaired by the addition of pancreatin.

Bacterial Infections↗
PubMed1984

Resection of terminal vagal branches to parietal cell mass in the treatment of duodenal ulcer.

In order to completely denervate the parietal cell mass and to prevent the undesirable side effects of highly selective vagotomy, the authors devised a new and simpler modified operative procedure. First, the anterior and posterior leaves of the lesser omentum are divided from the stomach at their attachment 6 cm proximal to the pylorus to the level 2 to 2.5 cm below the esophagogastric junction. Second, a circular seromuscular incision is made at the anterior and posterior wall of the stomach from the lesser curve 2 to 2.5 cm below the cardia to the highest short gastric artery at the greater curve. Forty cases followed for an average period of 21.8 months with satisfactory postoperative results reported.

Adult↗
PubMed1983

[Field experiences with the 6-month Singapore therapy in the treatment of open lung tuberculosis in Cambodian refugees].

The particular situation of a refugee camp with transit character, as represented by "holding Centre Khao-I-Dang" (KID) for Cambodian refugees in Thailand, had to be taken into consideration when determining the therapy plan for the disease that is epidemiologically most important, smear-positive pulmonary tuberculosis. Under Singapore conditions daily administration of isoniazid (H) and rifampicin (R) for 6 months combined with a 2-month intensive phase of streptomycin (S) and pyrazinamide (Z) daily proved highly effective. The large-scale transfers in KID in February and March 1981 led to consistent administration of this therapy plan, which is recommended by the WHO. By the end of September 1981 61 patients aged 15 years and over had entered the "Thai/Swiss Red Cross TB Programme". Criterion for entrance was the presence in sputum of acid-fast bacilli in the Ziehl-Neelsen stain. The routine examinations consisted of three microscopic sputum examinations per month, a sputum culture and a chest x-ray before commencement of therapy, followed by a chest x-ray at the end of the intensive phase and at the end of therapy. Efficacy and side effects of the 6-month therapy in our collective were similar to those of the Singapore study.

Adolescent↗
PubMed1982

[Sobrerol as expectorant in patients with stable chronic respiratory tract infections. A controlled study].

A randomized double-blind crossover study compared the clinical effectiveness of 14-day treatment with 400 mg/day of sobrerol and placebo in 23 patients with stable chronic bronchial disease. In a further open trial phase all patients received 2.0 g glyceringuaiacol per day. During the 9-week trial, subjective symptoms and findings were recorded by numerical code, side-effects listed, pulmonary function tests performed and sputum physical characteristics determined on a weekly basis. Data was statistically analyzed using an analysis of variance adapted from HILLS and ARMITAGE, the Wilcoxon matched-pairs signed-ranks test, the paired t-test and the %2 test. Both subjective assessment of overall clinical efficacy and statistical analysis of the above factors failed to show any significant advantage of sobrerol over placebo. Sputum physical characteristics failed to reveal a significant difference between sobrerol and placebo, with the exception of a temporary reduction in sputum volume (p less than 0.05) on the fourth day of therapy with sobrerol. Similarly, 2.0 g glyceringuaiacol for 14 days failed to influence subjective symptoms, pulmonary function tests or sputum physical characteristics. In conclusion, sobrerol is a further example of an expectorant lacking evidence of clinical effectiveness in the management of bronchial secretions in patients with stable chronic bronchial disease.

Adult↗
PubMedDate not supplied

Interstrain pseudorecombinants of cowpea chlorotic mottle virus: effects on systemic spread and symptom formation in soybean and cowpea.

Full-length complementary DNA (cDNA) copies of genomic RNA1, RNA2, and RNA3 segments of cowpea chlorotic mottle virus (CCMV) strains D, N, and S were synthesized using polymerase chain reaction and were cloned downstream of a T7 RNA polymerase promoter. Mixtures of the homologous in vitro-transcribed RNAs produced typical CCMV symptoms when inoculated on soybean (cv. Bragg) and cowpea (cv. California Blackeye) plants. Using either gel-purified or in vitro-transcribed CCMV RNA components, the pseudorecombinants SSD, SSN, DDS, and NNS were constructed. The properties of these pseudorecombinants were tested by comparing the induced symptoms, virus concentration, and systemic spread. These studies revealed a direct involvement of RNA3 genetic information in necrotic lesion formation and in breakage of CCMV resistance in soybean. Exchanges between RNA1 or RNA2 components further affected the biological features of reassorted CCMV variants. The true nature of the pseudorecombinants was confirmed by reconstitution of the parental strains from the corresponding pseudorecombinant RNA components.

Base Sequence↗
PubMedDate not supplied

No demonstrable effect of sobrerol as an expectorant in patients with stable chronic bronchial diseases.

A randomized double-blind cross-over study compared the clinical effectiveness of a 14-day treatment with 400 mg X day-1 of sobrerol and placebo in 23 patients with stable chronic bronchial disease. During the seven week trial, subjective symptoms and findings (cough frequency and severity, difficulty in raising sputum, dyspnoea) were recorded, pulmonary function tests performed and sputum physical characteristics (24-h sputum volume, purulence, cell concentration, protein, sputum dry weight and "apparent" viscosity) determined on a regular basis. Side-effects were closely monitored. Both subjective assessment of overall clinical efficacy as well as statistical analysis of the above mentioned factors failed to show any significant advantage of sobrerol to placebo--except for a transient decrease of the 24-h sputum volume. Sobrerol appears to be another example of an expectorant lacking evidence of clinical effectiveness in the management of chronic bronchial secretions.

Bronchial Diseases↗