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Biomedical subjects

W Cheng

Publications and source records attributed to W Cheng.

At least 163 records · Page 9Linked to original sources

[Studies of mtDNA of Ustilago maydis. I. Cloning and gene mapping].

This paper covers the following studies of mtDNA of Ustilago maydis. (1) By inserting the Bam HI and Pst I fragments of the mtDNA into the corresponding sites of pBR322, we cloned a unique sequence of 49.6 kb, accounting for 89.3% of the mitochondrial genome (60.7 kb). (2) With heterogenous genes from plants or fungi as probes, we identified seven genes, and mapped them onto the restriction map of the mt DNA. The genes were arranged in such an order: -UmCOB-UmOXII-S-rR NA-UmOXIII-L-rRNA-UmATPase6-UmOXI-. (3) We tried to express the three cloned genes, UmOXII, UmOXIII, and Um-ATPase 6, in E. coli maxcel expression system, but no specific protein was observed.

Chromosome Mapping↗

[Studies on mtDNA of Ustilago maydis. II. Restriction mapping].

A restriction map was constructed for mtDNA of Ustilago maydis. The fragment order for each restriction enzyme was determined by DNA hybridization and fragment overlapping. The restriction sites were located by analysing the secondary digestions of the cloned mtDNA fragments. It was also found that the mtDNA of U. maydis was a circle molecule (60.7 kb), without recognizable repeat sequence.

DNA, Mitochondrial↗

Improvement in chronic hepatocerebral degeneration following liver transplantation.

Chronic progressive hepatocerebral degeneration with spastic paraparesis, dementia, dysarthria, ataxia, tremor, and neuropsychiatric symptoms follows long-standing portal-systemic shunting, is associated with structural changes in the central nervous system, and does not respond to conventional therapy for hepatic encephalopathy. A case of advanced chronic liver disease with severe, progressive hepatocerebral degeneration after 23 yr of portal-systemic shunting is reported in whom there was significant objective improvement in intellectual function and in the chronic neurological signs 3 mo after orthotopic liver transplantation and further improvement 12 mo after transplantation.

Adult↗

[The changes of beta-glucuronidase in rabbit model with calcium bilirubinate stone].

The aim of the present study is to determine the beta-glucuronidase changes in bile and hepatobiliary tissue of rabbit model having pigment gallstone by means of biochemical and enzymehistochemical assay methods. The result showed both of the bacterial and non-bacterial beta-glucuronidase take part in the course of pigment gallstone formation. The bacterial beta-glucuronidase level increased quickly before the formation of gallstone, then decreased with control of bacterial infection. Non-bacterial beta-glucuronidase increased slowly in pro-formation stage of gallstone, then kept high level for long period of time. The relationship between beta-glucuronidase and pigment gallstone formation is also discussed.

Animals↗

Castanospermine blocks the hyperglycemic response to carbohydrates in vivo: a result of intestinal disaccharidase inhibition.

Castanospermine is a potent inhibitor of rat intestinal glycohydrolases in vitro and prevents the hyperglycemic response to an oral sucrose challenge in vivo. Among the glycohydrolases tested, castanospermine was most effective against sucrase with an IC50 of 1.1 x 10(-7) M. In vivo, a significant effect was seen at doses less than 1 mg/kg in both normal and streptozotocin-treated rats. Castanospermine has a prolonged duration of activity in vivo with significant activity when administered 4 hours before sucrose.

Alkaloids↗

Enzyme-linked immunosorbent assay for Campylobacter pyloridis: correlation with presence of C. pyloridis in the gastric mucosa.

Antibody to Campylobacter pyloridis was measured by ELISA in the sera of 160 patients from whom gastric biopsy specimens were also obtained. The antigen was an acid-glycine extract of C. pyloridis, and titers ranged from 80 to 22,000 ELISA units (EU). Of 117 patients in whom C. pyloridis was detected microbiologically or histologically, 87 (74%) had a titer greater than or equal to 300 EU, and only one had a titer less than 150 EU. Of 43 patients in whom C. pyloridis was not detected, only two (5%) had a titer greater than 300 EU. Thus, for a titer of 300 EU the ELISA test had a specificity of 97% and a sensitivity of 81%. At 150 EU the specificity was 78%, and the sensitivity was 99%. Histological diagnosis of active chronic gastritis was associated with a high median ELISA titer (485 E), chronic gastritis with a much lower titer (150 EU), and normal histology with a titer of 110 EU. Discriminating use of this serological test could be of assistance to detect C. pyloridis in the gastric mucosa.

Adult↗

Effect of triiodothyronine on (Na+ G K+)-adenosine triphosphatase and (Na+ + Mg2+)-dependent phosphorylated intermediate in rat salivary glands.

The present studies concern the effect of triiodothyronine (T3) on rat salivary (Na+ + K+)-adenosine triphosphatase (NaK-ATPase). The results indicate that T3 selectively increased submandibular and parotid NaK-ATPase units with a single, large dose of T3, different dosage of T3, three successive doses of T3 given on alternate days, and "physiological" doses of T3 with daily injection for 2 weeks. Sublingual NaK-ATPase was insensitive to T3 in the above experiments. The effect of T3 on submandibular and parotid NaK-ATPase is selective since Mg-ATPase and 5'-nucleotidase showed no significant differences under different thyroid status. The lack of response of NaK-ATPase to reverse T3, further substantiates the specificity of T3 on salivary NaK-ATPase.

Animals↗

Ultrasound-guided hydrostatic reduction of childhood intussusception: technique and demonstration.

The authors review the technique of ultrasound-guided hydrostatic reduction of childhood intussusception and illustrate, in real-time fashion, the treatment of three cases with this technique. Two cases of successful reduction of ileocolic intussusception are demonstrated. The third case is an example of the complex fronded appearance of ileo-ileocolic intussusception and failed reduction. This technique is recommended as an alternative method for the treatment of childhood intussusception, as it does not involve ionizing radiation and is a simple and safe procedure.

Enema↗