Fine dissection of the tarsal tunnel in 60 cases.

The fine dissection of nerves and blood vessels in the tarsal tunnel is necessary for clinical operations to provide anatomical information. A total of 60 feet from 30 cadavers were dissected. Two imaginary reference lines that passed through the tip of the medial malleolus were applied. A detailed description of the branch pattern and the corresponding position of the posterior tibial nerve, posterior tibial artery, medial calcaneal nerve and medial calcaneal artery was provided, and the measured data were analyzed. Our results can be summarized as follows. I. A total of 81.67% of the bifurcation points of the posterior tibial nerve, which was divided into the medial and lateral plantar nerves, were located within the tarsal tunnel, not distal to the tarsal tunnel. II. The bifurcation points of the posterior tibial artery were all located in the tarsal tunnel. Almost all of the bifurcation points of the posterior tibial artery were lower than those of the posterior tibial nerve. The bifurcation point of the posterior tibial artery situated distal to the tarsal tunnel was not found. III. The number and the origin of the medial calcaneal nerves and arteries were highly variable.

HES1 inhibits adipogenesis of porcine mesenchymal stem cells via transcriptional repression of FAD24.

Adipogenesis, the development from preadipocytes or mesenchymal stem cells (MSCs) to mature adipocytes, is regulated by a network of signaling pathways and transcription factors. The involvement of Notch signaling and its effector HES1 in adipogenesis has been investigated in several studies with conflicting results. The underlying mechanisms remain unclear because of the lack of information about HES1 target genes during adipocyte differentiation. As a novel gene transiently up-regulated in early adipogenesis, FAD24 functions as a positive regulator of adipocyte differentiation in both preadipocytes and MSCs. In the present study, we report that the expression level of FAD24 is inversely associated with that of HES1 in porcine MSCs after adipogenic induction. Enforced overexpression of HES1 in MSCs during the early stage of adipogenesis significantly repressed the transcription of FAD24 (P < 0.01) and the other pro-adipogenic genes (P < 0.05), resulting in reduced intracellular lipid accumulation. Sequence analysis showed that porcine FAD24 harbors an evolutionarily conserved HES1 binding site in its proximal promoter region. Functional HES1, but not its dominant-negative mutant, markedly reduced the promoter activity of FAD24 (P < 0.01). Site-directed mutation and chromatin immunoprecipitation further confirmed that HES1 inhibits FAD24 transcription by direct binding to the promoter. Taken together, we identified FAD24 as a novel downstream target of HES1 during adipogenesis. Our data suggest that HES1-mediated repression of FAD24 transcription at the early stage of adipocyte differentiation may contribute to the impaired adipogenesis induced by the Notch-HES1 signaling pathway.

Multiple forms of formamidopyrimidine-DNA glycosylase produced by alternative splicing in Arabidopsis thaliana.

Formamidopyrimidine-DNA glycosylase (FPG) catalyzes the initial steps in the repair of DNA containing oxidized purines. Two cDNA clones from Arabidopsis thaliana encoding homologs of bacterial FPG have previously been described. We now report that there are at least five additional variants of FPG mRNA in Arabidopsis, each apparently produced from the same gene (AtMMH) by alternative splicing. Thus, AtMMH, like at least four other genes in the base excision repair pathway of human cells, produces multiple forms of protein product through alternative splicing. The variant forms of Arabidopsis FPG may be localized in different locations in the cells, may have different preferences for oxidized substrates, and/or may recruit different proteins that guide the subsequent steps of base excision repair.

Alternative forms of formamidopyrimidine-DNA glycosylase from Arabidopsis thaliana.

Formamidopyrimidine-DNA glycosylase (FPG) catalyzes the initial steps in the repair of DNA containing oxidized purines. Two complementary DNA clones encoding homologs of bacterial FPG, designated Atfpg-1 and Atfpg-2, have been isolated from Arabidopsis thaliana. They are products of alternative splicing of the transcript of a single gene. Proteins encoded by both clones, AtFPG-1 and AtFPG-2, engineered to contain oligohistidine sequences on their C-terminal ends, were expressed in Escherichia coli and purified, and their activities were assayed. Both proteins cleaved DNA that contained apurinic sites, indicating that they have abasic lyase activity. AtFPG-1, but not AtFPG-2, showed significant cleavage of a double-stranded oligonucleotide that contained 8-oxo-guanine, indicating that the structural differences between the two proteins influence their enzymatic activities. However, both proteins were able to cleave the same sites in DNA that was treated with visible light in the presence of methylene blue.

Sex health education in university.

PIP: A sex health information class was introduced to almost 100 students at Capital Normal University. The late Premier Zhou Enlai had suggested sex health education for adolescents in 1963. Although the State Education Commission issued several circulars regarding the development of an educational program about puberty for middle schools, the directives were not followed properly. 4000 junior middle school students in Beijing were surveyed to ascertain their sexual psychological development; it was found that the teenagers were maturing sexually at an earlier age. However, the age at marriage was late due to a policy of deferred marriage. Despite the importance of guidance during the middle school period, teaching materials and teachers are not available. According to Dr. Gao Dewei (chief of the Research Centre for Sexual Health Education for the Capital Normal University), courses should be initiated at normal colleges and universities to provide teachers in this area. Beginning in 1993, a Sex Education Programme was introduced at the university in 3 steps: 1) an elective course in sex health; 2) a series of elective courses for biology majors; and 3) a subsidiary specialty course in sex health education open to students from all departments. Step 3 began in 1995. Sexual morals and ethics, sexuality laws, sex physiology and psychology, sexual health care, sex sociology, and sex pedagogy are covered.^ieng

Analogues of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A) as potential anti-platelet-aggregation agents.

Dense granules of platelets contain a high content of diadenosine 5',5'''-P1,P4-tetraphosphate (Ap4A). We have previously demonstrated an antithrombotic effect of this compound in a live rabbit model. In the present study we find that certain synthetic Ap4A analogues are superior to Ap4A in inhibiting ADP-induced aggregation of human platelets. Analogues having a P--C--P bridge located in the P2,P3 position of Ap4A are the most potent inhibitors. These analogues are also resistant to hydrolytic enzymes. Analogues having the above characteristics exhibit competitive inhibition with ADP in the ADP-induced platelet aggregation reaction. These compounds, such as AppCHFppA, may be useful as antithrombotic agents. The analogues ApSppSpA and ApSpCHFpSpA also showed good inhibitory effects on ADP-induced platelet aggregation. In addition, this action of Ap4A and its analogues provides an example of a dinucleotide inducing an antagonistic effect by occupying an extracellular mononucleotide binding site on platelets. It calls attention to the possibility that Ap4A and its analogues may act in a similar way in whole organisms, triggering effector or inhibitory responses in any one of a variety of cells.