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Biomedical subjects

Y S Xu

Publications and source records attributed to Y S Xu.

At least 19 recordsLinked to original sources
PubMed2006

Mutations in the ATP2C1 gene in Chinese patients with Hailey-Hailey disease.

Hailey-Hailey disease (HHD; MIM 16960) is a rare autosomal dominant hereditary disorder characterized by recurrent eruption of vesicles and bullae, predominantly involving the body folds. It is caused by heterozygous mutations in the ATP2C1 gene, encoding the human secretory pathway Ca2+/Mn2+-ATPase protein 1 (hSPCA1). When we studied Chinese patients with HHD, we found two different heterozygous mutations, Q506X and G353V, the former previously reported in a Hungarian patient, and the latter being a novel mutation. In a 38-year-old patient from a four-generation pedigree with a 3-year history of severe recurrent blisters, we identified a C-->T transition at nucleotide 1696, c(1696C-->T), in exon 17 of ATP2C1, resulting in a nonsenes mutation, Gln506X, which resulted in a premature termination codon. In the second patient, who represented a occurrence of sporadic Hailey-Hailey disease, a G-->T transversion of nucleotide, c(G1238T), in exon 13 of ATP2C1 was detected, which resulted in a Gly353-->Val amino acid substitution (G353V). Our molecular findings further demonstrate that the mutational events in the human ATP2C1 gene encoding the hSPCA1 pump play an important role in the pathogenesis of HHD.

Adult↗
PubMed2000

Evidence for gelsolin as a corneal crystallin in zebrafish.

We have shown that gelsolin is one of the most prevalent water-soluble proteins in the transparent cornea of zebrafish. There are also significant amounts of actin. In contrast to actin, gelsolin is barely detectable in other eye tissues (iris, lens, and remaining eye) of the zebrafish. Gelsolin cDNA hybridized intensely in Northern blots to RNA from the cornea but not from the lens, brain, or headless body. The deduced zebrafish gelsolin is approximately 60% identical to mammalian cytosolic gelsolin and has the characteristic six segmental repeats as well as the binding sites for actin, calcium, and phosphatidylinositides. In situ hybridization tests showed that gelsolin mRNA is concentrated in the zebrafish corneal epithelium. The zebrafish corneal epithelium stains very weakly with rhodamine-phalloidin, indicating little F-actin in the cytoplasm. In contrast, the mouse corneal epithelium contains relatively little gelsolin and stains intensely with rhodamine-phalloidin, as does the zebrafish extraocular muscle. We propose, by analogy with the diverse crystallins of the eye lens and with the putative enzyme-crystallins (aldehyde dehydrogenase class 3 and other enzymes) of the mammalian cornea, that gelsolin and actin-gelsolin complexes act as water-soluble crystallins in the zebrafish cornea and contribute to its optical properties.

Amino Acid Sequence↗
PubMed2000

Transketolase gene expression in the cornea is influenced by environmental factors and developmentally controlled events.

PURPOSE: Transketolase (TKT) has been proposed to be a corneal crystallin, and its gene and protein are abundantly expressed in the corneal epithelium of several mammals. A marked up-regulation of TKT gene expression coincides with the time of eyelid opening in the mouse. Here, we examined whether exposure to incident light contributes to the up-regulation of TKT gene expression during cornea maturation. METHODS: Mice were raised in either standard light/dark cycling conditions or total darkness. In some cases, subcutaneous injections of epidermal growth factor (EGF) were given beginning on the day of birth to induce early eyelid opening. RNA was prepared from the corneas of mothers and pups and subjected to Northern blot analyses. In addition, the relative levels of TKT mRNA and/or enzyme activity were examined in the corneas of human, bovine, rat, chicken, and zebrafish. RESULTS: TKT mRNA levels were 2.1-fold higher in the corneas of 25-day-old mouse pups ( 12 days after eyelid opening) that had been born and raised in light/dark conditions compared to pups born and raised in total darkness. By contrast, the level of TKT mRNA in the mature corneas of adult mice maintained in the dark for 2-8 weeks did not vary greatly from those of mice maintained in light/dark conditions. Interestingly, TKT mRNA levels in the corneas of dark-raised mice, although reduced, did exhibit the increase characteristically observed before and after eyelid opening. In addition, TKT mRNA levels were elevated fivefold in the corneas of 28-day-old mice raised in darkness and injected with EGF compared to uninjected mice also deprived of light. The EGF-injected mice opened their eyes 3 days early, and their corneal epithelium did not grossly differ from that of control mice. TKT mRNA and/or enzyme activity was found to be much higher in the corneas than in other tissues of humans, bovines, and rats but was extremely low in the corneas of chicken and zebrafish. CONCLUSION: Our studies suggest that both exposure to incident light and events surrounding the process of eyelid opening play a role in the up-regulation of TKT gene expression observed during corneal maturation in mice. Light appears to play a less important role in the mature cornea in maintaining high levels of TKT gene expression. The low levels of TKT in the cornea of chicken and zebrafish support the notion that TKT acts as a taxon-specific enzyme-crystallin in mammals. The involvement of environmental signals for this putative, mammalian cornea crystallin contrasts with the purely developmental signals involved in the up-regulation of the crystallin genes of the lens.

Adult↗
PubMed1998

Complete replication of human sperm genome in egg extracts from Xenopus laevis.

To examine the ability of Xenopus egg extracts to support a complete replication cycle of human sperm genome, demembranated human spermatozoa were incubated with the extract from activated Xenopus laevis eggs. Most sperm heads were decondensed within 15 min. The heads became round within 30 min with diameters of 10-30 microns. The process of DNA replication in the pronuclei was monitored by two methods, bromodeoxyuridine incorporation and flow cytometry. The results indicate that DNA replication was initiated approximately 1.5 h after membrane structure formation and that it lasted up to 9 h. The amounts of DNA in most pronuclei were doubled by 4-9 h, depending on which donor toad was the source of the egg extract. Inclusion of the protein synthesis inhibitor, cycloheximide (100 micrograms/ml), had no obvious effect on human sperm DNA replication but appeared to prevent the pronuclei from degradation after a prolonged period (> 6 h) of incubation. After storage in liquid nitrogen for > 1.5 mo, the efficiency of the egg extracts in supporting sperm head decondensation and DNA replication was reduced for human sperm but not for Xenopus sperm. Possible applications of the use of Xenopus egg extract for human sperm activation and DNA replication are discussed.

Animals↗
PubMed1993

Reperfusion arrhythmias in acute myocardial infarction.

In 27 patients with acute myocardial infarction (MI) and their infarct-related coronary artery being completely occluded who received thrombolytic therapy or percutaneous transluminal coronary angioplasty, reperfusion was confirmed by immediate coronary angiography in 24. Reperfusion arrhythmias (RA) occurred in 19 (79.2%) of the patients, including ventricular arrhythmias in 13 (54.2%). Ventricular fibrillation and sustained ventricular tachycardia developed in 2 (8.4%) and accelerated idioventricular rhythm in 5 (20.8%), the latter was a reliable indicator of coronary recanalization. Transient sinus bradycardia or AV block occurred in 10 (66.7%) of the 15 patients with inferoposterior MI. The occurrence of RA was not related to the duration of ischemia; ventricular RA was also not related to the location of MI and the occurrence and severity of ischemic arrhythmias before reperfusion.

Aged↗
PubMed1993

[Quantitative assessment of the effect of nitroglycerin on left ventricular function with two-dimensional echocardiography in patients with myocardial infarction].

The effect of sublingual and intravenous nitroglycerin (SLNTG and IVNTG) on left ventricular global and segmental systolic function was quantitatively assessed with two-dimensional echocardiography (2DE) in 28 cases of myocardial infarction (MI), including a group without heart failure of 13 and another group with heart failure of 15. The results showed that after SLNTG and IVNTG the left ventricular end-diastolic and end-systolic volumes were significantly decreased in both groups (P < 0.05-0.001), the left ventricular global systolic function was improved particularly in MI patients with heart failure during IVNTG. The wall motion in the normal and/or hypokinetic segments was enhanced after both SLNTG and IVNTG. It was shown that nitroglycerin could strengthen the left ventricular global systolic function in patients with MI.

Echocardiography↗
PubMed1991

Filtering noise from images with wavelet transforms.

A new method of filtering MR images is presented that uses wavelet transforms instead of Fourier transforms. The new filtering method does not reduce the sharpness of edges. However, the new method does eliminate any small structures that are similar in size to the noise eliminated. There are many possible extensions of the filter.

Artifacts↗
PubMed1991

Bacteriological composition and structure of granular sludge adapted to different substrates.

The bacteriological composition and ultrastructure of mesophilic granular methanogenic sludge from a large-scale Upflow Anaerobic Sludge Blanket reactor treating wastewater from a sugar plant and of sludge granules adapted to ethanol and propionate were studied by counting different bacterial groups and by immunocytochemical methods. Propionate-grown granular sludge consisted of two types of clusters, those of a rod-shaped bacterium immunologically related to Methanothrix soehngenii and those consisting of two different types of bacteria with a specific spatial orientation. One of these bacteria reacted with antiserum against Methanobrevibacter arboriphilus AZ, whereas the other is most likely a propionate-oxidizing bacterium immunologically unrelated to Syntrophobacter wolinii. Sludge granules obtained from the large-scale Upflow Anaerobic Sludge Blanket reactor and granules cultivated on ethanol did not show the typical spatial orientation of bacteria. Examination of the bacterial composition of the three types of granules by light and electron microscopy, the most-probable-number method, and by isolations showed that M. arboriphilus and M. soehngenii were the most abundant hydrogenotrophic and acetoclastic methanogens in propionate-grown sludge. Methanospirillum hungatei and Methanosarcina barkeri predominated in ethanol-grown granules, whereas many morphotypes of methanogens were abundant in granules from the full-scale reactor.

Ethanol↗
PubMed1985

Hormone concentrations before and after semen-induced ovulation in the bactrian camel (Camelus bactrianus).

During the follicular phase of bactrian camels, basal concentrations of LH were 2.7 +/- 1.2 ng/ml. By 4 h after insemination peak values of 6.9 +/- 1.0 ng/ml occurred. In addition, a smaller LH peak (5.4 +/- 2.5 ng/ml) appeared 1 day before regression of the follicle began in unmated camels. During the follicular phase peripheral plasma progesterone values were low (0.36 +/- 0.28 ng/ml), but values increased to reach 1.73 +/- 0.74 ng/ml at 3 days and 2.4 +/- 0.86 ng/ml at 7 days after ovulation. Plasma oestradiol-17 beta concentrations were 26.8 +/- 9.0 pg/ml during the follicular phase and 30.8 +/- 5.1 pg/ml when the follicle was maximum size. Values fell after ovulation but rose to 29.8 +/- 6.5 pg/ml 3 days later.

Animals↗