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Biomedical subjects

Y Yu

Publications and source records attributed to Y Yu.

At least 37 records · Page 2Linked to original sources
PubMed1990

Studies on antipeptic ulcer agents: a structure-activity relationship analysis of aldehyde semicarbazones and aryl hydrazones.

Twenty-eight condensation products of heterocyclic-a-carboaldehydes with N-aminooxazolidones, semicarbazides, thiosemicarbazides and benzoxycarbonyl hydrazide were synthesized so as to deduce the antiulcer pharmacophore or fragment of furazolidone (I), a prototype which has shown therapeutic efficacy in patients with gastric and duodenal ulcers. SAR analysis of the compounds indicated that the substitution of furan, thiophene, pyrrole or N-methyl pyrrole rings for 5-nitrofuran and the cleavage of the oxazolidone ring did not fully destroy the activity. The electron density of the carbonyl group was found to be of importance. A lead structure, therefore, was derived for further optimization.

Animals↗
PubMed1990

ADPRT-mediated decrease of cellular NAD content and the detection of chemically induced DNA damage--development of a new short-term screening test for mutagens.

It was found that the DNA-damaging agents N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), methyl-methanesulphonate (MMS) and 4-nitroquinoline-N-oxide (4NQO) could stimulate ADP-ribosyl transferase (ADPRT) activity and reduce the cellular NAD content in a dose-dependent way. The reduction of NAD after DNA damage could be partially or completely prevented by ADPRT inhibitors, 3-aminobenzamide or nicotinamide, which showed no influence on reduction of NAD induced by metabolic blocking agents. Therefore, a simple and specific method to detect DNA-damaging mutagens by measuring ADPRT-mediated decrease of cellular NAD content was explored. Using beta-naphthoflavone, a mixed function oxygenase inducer, together with induced or uninduced human amnion FL cells, it was found that aflatoxin B1, benzo(a)pyrene, 2-acetylaminofluorene, 9,10-dimethylanthracene and ethylcarbamate could induce the ADPRT-mediated decrease of cellular NAD content, while 4-acetylaminofluorene, anthracene, isopropyl-N-(3-chlorophenyl)-carbamate, beta-propiolactone, gamma-butyrolactone, cyclophosphamide and safrol could not. The results indicate that this is a cheap and specific method to detect DNA damage caused by chemical carcinogens/mutagens with a specificity approaching that of the unscheduled DNA synthesis assay.

Amnion↗
PubMed1990

Silk-induced asthma in children: a report of 64 cases.

A total of 64 children less than 15 years of age with asthma caused by silk were studied. The diagnosis was based on a history of wheezing, positive skin tests to silk, positive conjunctival or nasal provocation tests, or serum IgE-Sw (silk waste). The average age of onset was 4 years 2 months. Sex ratio (M:F) was 3.6:1. A positive skin test is essential for the diagnosis. Conjunctival provocation tests were performed in 80% of cases because of reliability, safety, and convenience. The first symptom appeared an average of 10 months after initial exposure to silk. In 61% of patients, asthma was accompanied by allergic rhinitis but in only 14% of cases by conjunctivitis. In most cases, asthma occurred in winter, due to seasonal use of bed quilts or clothes filled with silk. Silk is a highly potent allergen. The average mean wheal diameter elicited by silk in prick testing was larger than two histamine equivalent prick tests. A cross reactivity exists among mulberry silk, and silkworm cocoons, batryticated silkworms, and silkworm chrysalis.

Adolescent↗
PubMed1990

Immunopotentiating effect of traditional Chinese drugs--ginsenoside and glycyrrhiza polysaccharide.

The immunopotentiating effects of the traditional Chinese drugs Ginsenoside (GS) and Glycyrrhiza polysaccharide (GPS) are reported. It was demonstrated that GS promotes the phagocytic activity of plaque-forming cells (PFC) and enhances the mitogenesis of T and B lymphocytes primed by mitogens. The mechanism of these effects is related to the ratio of cGMP to cAMP. GS also plays a role in the NKC-IFN-IL-2 regulatory system, inhibits the growth of tumor cells, and antagonizes the suppression of ADCC and NK cytotoxicities in mice with surgical stress. GS exhibits bidirectional effects on immunological functions. GPS increases the phagocytosis of macrophages, induces macrophages to secret IL-1, enhances both NK and ADCC activities, behaves as a mitogen of B lymphocytes, inhibits the multiplication of several viruses, and induces the release of IFN from spleen cells.

Adjuvants, Immunologic↗
PubMed1990

Preventive effect of Fluosol-DA for paraplegia encountered after surgical treatment of the thoracic aorta. Preliminary results in a dog model.

The effectiveness of Fluosol-DA (Green Cross Corporation, Osaka, Japan) on circulatory dynamics and neurologic outcome in dogs with ischemic spinal cord injury produced by aortic crossclamping was tested. The control group (receiving saline solution) had an elevated mean aortic proximal pressure (112.9 +/- 30.2 mm Hg versus 175.3 +/- 20.5 mm Hg, p greater than 0.05) and a drastic drop in mean distal aortic pressure (112.9 +/- 30.2 mm Hg versus 29.8 +/- 11.2 mm Hg, p less than 0.05). Although the same trend occurred in dogs treated prophylactically with Fluosol-DA, these changes were not statistically significant. However, there was a significant difference in mean distal aortic pressure during the ischemic phase between the two groups (58.9 +/- 16.0 mm Hg versus 29.8 +/- 11.2 mm Hg, p less than 0.05). Postoperatively all animals had mean arterial pressures within the normal range. All dogs in the control group were paraplegic (partial or complete); the treatment group had one dog with partial paraplegia. The difference between the mean neurologic scores of the two groups was of high statistical significance (3.7 +/- 0.5 versus 1.6 +/- 1.0, p less than 0.05). Our preliminary results show that prophylactic use of Fluosol-DA has favorable effects on hemodynamics and neurologic outcome in dogs with spinal cord ischemia produced by aortic crossclamping. The high propensity of the drug to carry oxygen and carbon dioxide and to provide nutritional support to the ischemic area with resultant improvement in local microcirculation and blood rheology are some speculative mechanisms advocated for these changes.

Animals↗
PubMed1989

Completion of the sequence of bluetongue virus serotype 10 by the characterization of a structural protein, VP6, and a non-structural protein, NS2.

The sequence of cDNA clones representing the entire genome of bluetongue virus serotype 10 (BTV-10) has been completed by the analysis of data obtained for the S8 and S9 segments. Each DNA clone has been sequenced completely and the deduced amino acid sequences have been analysed. The sequences of the S8 and S9 gene products as well as another two previously published small gene products (S7 and S10) have been compared with the corresponding size gene products of reovirus type 1. The data do not indicate a relationship between the small proteins of these two viruses except some distant homologies between the BTV VP7 protein and the sigma 1 protein of reovirus. The characteristics of all the BTV-10 genome segments, the deduced primary gene products and their possible functions are summarized.

Amino Acid Sequence↗
PubMed1989

[Surgical treatment and observation of the therapeutic results in 11 cases of tuberculous adherent intestinal obstruction].

11 cases with tuberculous adherent intestinal obstruction treated by means of exfoliating and resecting of fibrous plate and tuberculous focus curettage were reported. All were females with an age range of 22 to 44 years. The diagnosis was confirmed by operation and biopsy. 8 of them were complete obstruction and incomplete in 3.5 cases were strangulated by fibrous band. Bowel necrosis occurred in 3. A thorough exfoliating and resecting of fibrous plate were carried out in all cases, associated with enterectomy in 2 cases and ileocecectomy on one. No mortality and fistula formation in this series. Follow-up from 1.5 to 7 years in 8 cases. No obstructive signs of recurrence were noticed. Weight gained about 10-15 kg. postoperatively.

Adult↗
PubMed1989

Allergenicity of orange juice and orange seeds: a clinical study.

Oranges are considered to be common allergenic fruits in China. They may induce severe food allergy in sensitive individuals. Allergic histories were analyzed in 26 orange-sensitive patients. Intradermal tests with extracts of orange juice and seeds were performed in 16 out of the 26 patients. P-K test was performed in one patient. The allergic history analysis suggested that clinical symptoms of some orange-allergic subjects were different from other fruit allergies but similar to nut and other oil plant seed allergies. The skin test and P-K test showed that the major allergenic components of orange reside in orange seeds instead of orange juice. Systemic reactions developed in 5 patients after intradermal tests with 1:20-200 (w/v) orange seed extracts. We considered that orange seed contains high potent allergens which may induce orange sensitivity due to careless chewing of orange seeds.

Adult↗
PubMed1988

Cloning of cDNA coding for carbamyl phosphate synthetase I and changes in levels of CPS1 mRNA during hepatocarcinogenesis.

cDNA coding for carbamyl phosphate synthetase I was cloned from recombinant plasmid with insert complementary to the mRNA for CPS1 followed by hybrid-selected translation screening. The length of the insert CPS1 cDNA was approximately 800 base pairs. Using this cDNA as a probe, it was found by dot-blot analysis of the total RNAs and poly(A)+-RNAs isolated from rat livers with different pathological lesions induced by diethylnitrosamine that the levels of CPS1 mRNA were decreased, the decrease being correlated with the malignancy of hepatocytes during carcinogenesis.

Animals↗
PubMed1986

Transforming activity of human nasopharyngeal carcinoma DNA.

NIH 3T3 cells were transfected with the DNAs from biopsy specimens of human nasopharyngeal carcinoma (NPC, EBV DNA positive) using calcium phosphate precipitation method. The malignant, transformed foci of NIH 3T3 cells have been observed and cloned. The hybridization of transfectant DNA digested by EcoRI with total human leukocyte DNA as probe was performed. The strong signal of smear comparing with NIH 3T3 DNA as control was observed. It was implied that the putative human transforming sequences had been integrated into transformed cells. Employing soft agar culture, the transformed cells can grow and form cell colonies. Following transfer, the foci were able to grow and adhere to a glass wall. These cells were easily agglutinated by con A. The cloned foci have been inoculated into nude mice with the formation of highly malignant sarcomas. In preliminary experiments for characterizing the transforming sequences, Ha-ras and Blym 1 were found in transfectants derived from one of the NPC DNA samples. It is implicated that these two oncogenes might be responsible for the acquisition of malignant phenotypic character of some human NPC. The further identification of oncogenes in NPC is currently in progress.

Animals↗
PubMed1976

Distribution of growth hormone-release-inhibiting hormone (somatostatin) in the rat brain as observed with immunocytochemistry.

The objective was to determine the distribution of growth hormone-release-inhibiting hormone (somatostatin) in the rat brain using the peroxidase-antiperoxidase immunocytochemical method with antisera prepared against unconjugated, synthetic somatostatin. Somatostatin occurred in low quantity in the organum vasculosum of the lamina terminalis. It was present throughout the full length of the median eminence and occupied the entire width between the tuberoinfundibular sulci. Most somatostatin was located in the dorsal portion of the external lamina, and the amount varied according to the mediolateral position. The bodies labeled for somatostatin were most often granules; occasionally they appeared as clusters of granules that seemed to be membrane-enclosed. Some of these bodies appeared to be portions of axons. Many of the larger bodies were arranged alongside tanycytes, but no label was distributed generally in tanycyte cytoplasm. Somatostatin was highly concentrated in the proximal one-quarter of the infundibular stem and appeared in lower concentration throughout the distal portion of the stem. It was absent from the pars nervosa and pars intermedia of the pituitary gland. The distribution of somatostatin in the median eminence differed considerably from that of gonadotropin-releasing hormone. Somatostatin was identified in the ventromedial and/or dorsomedial hypothalamic nuclei of only two animals. Here it was probably located in axons that terminated on neuronal cell bodies but also may have been present in a restricted portion of the perikaryonal cytoplasm.

Animals↗
PubMed1975

Both NS and L proteins are required for in vitro RNA synthesis by vesicular stomatitis virus.

Vesicular stomatitis virions, Indiana serotype, were solubilized with high salt solubilizer and separated by ultracentrifugation into a supernatant fraction containing L, G, NS, and M proteins and pellet fraction containing the RNA complexed with N protein. NS protein was purified from the supernatnat fluid by sequential chromatography on phosphocellulose and diethylaminoethyl cellulose columns. The purified NS protein was assayed in a standard transcription system in combination with purified L protein and purified template (pellet fraction) prepared by renografin or CsCl banding. Results of the polymerase assays indicate that both L and NS proteins are required to reconstitute transcription activity with a highly purified template composed of only RNA and N protein. The NS protein polymerase activity is destroyed by trypsin but withstands 90 C temperatures for 10 min. Cytoplasmic NS protein can substitute for virion NS protein in the in vitro transcription assay.

Cell-Free System↗