Biomedical subjects

J Xia

Publications and source records attributed to J Xia.

At least 145 records · Page 8Linked to original sources

PubMed1996

Ratiometric measurement of endothelial depolarization in arterioles with a potential-sensitive dye.

A fluorescence ratio technique based on the voltage-sensitive dye 1-(3-sulfonatopropyl)-8-[beta-[2-di-n-butylamino)-6-naphythyl++ +]vinyl] pyridinium betaine (di-8-ANEPPS)has been developed for recording membrane potential changes during vascular responses of arterioles. Perfusion of hamster cheek pouch arterioles with the dye labeled the endothelial cell layer. voltage responses from the endothelium of intact arterioles were determined by analysis of voltage-induced shifts in fluorescence emission wavelengths from dye spectra imaged from the vessel wall. Membrane depolarization caused the dye spectrum to shift toward blue wavelengths, with maximal fluorescence changes near 560 and 620 nm. In isolated nonperfused arterioles, comparison of continuous dual-wavelength recordings with simultaneous microelectrode recordings showed that the ratio of fluorescence intensities (fluorescence at 620 nm to fluorescence at 560 nm) accurately followed changes in membrane potential (6-21 mV) during vasoconstriction. The dye response was linear with respect to potential changes from -56 to -6 mV, with a voltage sensitivity of 9.7% change in the ratio per 100 mV. Membrane potential responses from in vitro and in vivo arterioles after potassium stimulation consisted of rapid ( < 0.5 -s) depolarization followed by slow repolarization over several seconds. Potassium-induced depolarizations were conducted along arterioles, and the values of the electrical length constant for conducted depolarization determined by optical and microelectrode methods were in agreement. We conclude that ratio analysis of di-8-ANEPPS fluorescence emission can be used to accurately record membrane potential changes on the time scale of seconds during vasomotor activity from arterioles.

Animals↗

PubMed1996

[Quantitative study of velopharyngeal function post-palatoplasty]

The computer of nasopharyngeal fiberscope(NPF) for quantitative analysis was carried out to assess the palate articulation of 43 subjects,and normal articulation of 60 subjects.The rest,/a/,/s/and /m/ articulation of NPF pictures were calculated for veloparyngreal function via computer.

Journal Article↗

PubMed1996

[Investigation on VNTR in intron 40 of vWF gene in Chinese Han population].

The VNTR in the intron 40 of vWF gene was investigated with a method of combination of Amp-FLP and RFLP. Two amplified fragments from a heterozygous person were separated by a non-hydratable polyacrylamide electrolyte gradient electrophoresis. After elution from gel, the preliminary products were amplified again, the amplified fragments were digested with AluI, then the genotype could be directly determined through electrophoresis. For the first time SSCP was used to detect the subtypes of microsatellite DNA. 136 alleles were found from 156 unrelated Hans in Changsha area. There were 153 genotypes in this sample and all of them were heterozygous. The calculated heterozygosity was 0.9884. The distribution of genotypes was in according with the Hardy-Weinberg equilibrium. The polymorphic information content (PIC) was 0.9883. The polymorphism of this VNTR was the highest one in the Amp-FLPs that had been found before. Our data did not show any recombination even in 2 generations of 66 families and 3 generations of 5 families. Aco-dominant segregation was demonstrated.

Base Sequence↗

PubMed1996

[Study of chromosome painting for one rare carrier with complex translocation].

This paper reports that one rare male carrier with complex translocation, being married for eight years, made his wife consecutive seven times abortions, stillbirth and teratogenesis of early death. Using human chromosome 7 and 8-specific probe pools constructed with the technique of chromosome microdissection and PCR, we carried out chromosome painting research of the patients, and identified the karyotype was: 46, XY, -7, -8, -9, +der (7)t(7; 9) (q2200; p24), +der(8)inv ins(8; 7) (q2100; q31.2q2200), +der (9)t(9; 7) (p24; q31.2).ish der(7)t(7; 9) (wcp7+), der(8)inv ins(8; 7)(wcp7+, wcp8+), der(9)t(9; 7) (wcp7+). The technique of chromosome painting provided us an effective technique of molecular cytogenetics for the study of chromosomal abnormalities. The formation mechanism of the complex translocation of the carrier is discussed.

Adult↗

PubMed1996

[The new concept of the cutaneous vascular framework in the leg].

An anatomical study was carried out using 15 legs of fresh cadavers. According to skin angiography, the authors set up a new concept of the vascular structure of skin and skin flap. The characteristics of the blood supply to the skin were revealed and analyzed. The first vascular frame unit, the second vascular frame unit and the superficial fascial network were described. The willow-shaped descending vascular branches were found and discussed, and they constituted a special blood supply in subcutaneous tissue.

Adult↗

PubMed1996

[Surgical treatment of primary epicardial tumors].

Seven cases of primary epicardial tumors of 3200 cardiac operation cases were diagnosed definitely, including benign in 5, malignant in 2. Among them, readical resection was performed in 5 cases, partial resection in 1, and decompression of pericardium in 1. Data of this series were often regarded as tuberculous pericarditis or others incorrectly. UCC, CT and MRI were helpful in diagnosis. The authors emphasize early surgical treatment as soon as possible and using the different methods of operation whether to utilize cardiopulmonary bypass or not according to site, size and characteristics of tumors to resect tumors, if necessary, reconstruction the heart wall to maintain blood follow dynamics. The prognosis of the diseases was related to the pathology and the area of invasion of tumors.

Adolescent↗

PubMed1996

[Diagnosis and surgical management of pancreatic pseudocysts].

Fifty-two patients with pancreatic pseudocysts were treated surgically between 1968 and 1994. Clinical symptoms were non-specific. Ten patients with acute pancreatitis were managed conservatively and resolution occurred in 3 patients. 42 patients underwent operation. Internal drainage was performed in 28 patients, external drainage in 8, others in 6. Pancreatic fistulas occurred in the external drainage group, 2 patients died and 1 patient had the of recurred pseudocyst. There were no complications in the internal drainage group. It was quite different in the external drainage group. The management should differ in that acute and chronic pancreatic pseudocysts. Patients with pseudocysts of chronic pancreatitis could undergo emergent surgery of internal drainage because waiting 6 weeks for maturation of the pseudocysts after diagnosis was unnecessary and even hazardous. However, if pseudocyst developed after acute pancreatitis, it should be watched for up to 6-8 weeks. During this period the pseudocyst perhap disappeared spontanously or matured for surgery.

Adolescent↗

PubMed1995

Decomposition of carbon monoxide dehydrogenase into alpha metallosubunits and a catalytically-active form consisting primarily of beta metallosubunits.

Carbon monoxide dehydrogenase from Clostridium thermoaceticum, with an alpha 3 beta 3 quaternary structure, was incubated with dithiothreitol and 740-78,000 equiv/alpha 3 beta 3 of sodium dodecyl sulfate (SDS), followed by electrophoresis under anaerobic native conditions. Three catalytically-active bands and four inactive bands were obtained, in proportions dependent on the amount of SDS added. The catalytically-active bands, called SM-CODH, NM-CODH, and FM-CODH, migrated slower than, similar to, and faster than native enzyme, respectively. Two-dimensional electrophoresis revealed that SM-CODH and NM-CODH contained approximately equal proportions of the alpha and beta subunits, while the beta/alpha ratio for FM-CODH was about 2.7. The four inactive bands were identified as the beta subunit, two forms of the alpha subunit (called alpha and alpha'), and a form that migrated similarly to native enzyme. Overloaded gels revealed that alpha and each active band had brown color, indicating intact Fe-S clusters in these species. Higher concentrations of SDS (> 1600 equiv/alpha 3 beta 3) and/or incubation at temperatures > 15 degrees C yielded more alpha and beta subunits at the expense of the catalytically-active bands. When incubated at 70 degrees C in 78,000 equiv/alpha 3 beta 3 of SDS, alpha quantitatively converted to alpha', suggesting that alpha' is a denatured form. FM-CODH appears to be an intermediate in the decomposition of CODH by SDS and to have either an alpha 1 beta 3 or alpha 1 beta 2 quaternary structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Oxidoreductases↗

PubMed1995

Electromechanical coupling and the conducted vasomotor response.

Conducted vasomotor responses are viewed as one mechanism that functionally integrates the microvasculature. It is hypothesized that the conducted vasomotor response is the result of an electrical current and its passive electrotonic spread along the length of a microvessel. We tested this hypothesis in isolated, unpressurized arterioles from the hamster cheek pouch using conventional intracellular membrane potential recording techniques. The mean resting membrane potential (RMP) was -67 mV. KCl and phenylephrine (PE) pulse-stimulation applied through micropipettes could both induce transient depolarizations and vasoconstrictions at the site of stimulation (local) and at conducted (560 microns) sites. It was noted, however, that the conducted vasomotor response could not be induced until the conducted electrical response exceeded a threshold of -45 mV for a minimum amount of time. The relationship between the amplitude of constriction and the amplitude-time area of depolarization above -45 mV was the same for local and conducted KCl and for conducted PE but was significantly different from that for local PE. Nifedipine greatly reduced the local and conducted mechanical but not electrical responses. Our results indicate that the conducted vasomotor responses are the result of the generation and subsequent conduction of electrical signals along the vessel but that the corresponding mechanical response occurs only when the electrical response exceeds a threshold level.

Animals↗

PubMed1995

Cellular pathways of the conducted electrical response in arterioles of hamster cheek pouch in vitro.

We have previously shown that conducted vasomotor responses follow patterns that are consistent with a passive spread of electrical current along the length of the arterioles [(Xia and Duling, Am. J. Physiol. 269 (Heart Circ. Physiol. 38): H2022-H2030, 1995]. In this study, we define the cells through which the current flows. Isolated arterioles of hamster cheek pouch were used. The mean resting membrane potential (RMP) for randomly sampled arteriolar cells was -67 mV. When cell types were identified by dye injection, the RMPs were -68 and -67 mV for smooth muscle (SM) and endothelium (EC), respectively. Pulses of KCl induced transient, monophasic depolarizations at the site of stimulation (local), which were conducted decrementally along the length of the arteriole over several millimeters. During electrical conduction, three patterns of responses could be observed, but identical patterns of the conducted electrical responses were always observed in SM and EC. Phenylephrine stimulation also caused transient local and conducted depolarizations in both SM and EC. As with KCl stimuli, shapes of conducted electrical responses were identical in records made in both cell types. The results suggest that SM and EC are electrically coupled both homocellularly and heterocellularly.

Alcohols↗

PubMed1995

Dye tracers define differential endothelial and smooth muscle coupling patterns within the arteriolar wall.

Dye tracers were chosen, based on net charge, chemical structure, and reactive groups, to test for the existence of and to provide novel insight into channel selectivities of junctional pathways connecting smooth muscle and endothelial cells of the arteriolar wall. Dyes were injected into individual smooth muscle or endothelial cells of hamster cheek pouch arterioles using microiontophoresis. Coupling, independent of tracer net charge, was seen both within and between cell layers. Endothelial cells were well coupled by all of the tested dyes. Smooth muscle junctions appeared less effective in dye transfer than endothelial junctions. Lucifer yellow was confirmed to be a poor tracer of smooth muscle gap junctions, and remarkably this dye and other related sulfate-containing molecules interfered with dye movement through smooth muscle but not endothelial junctions. Myoendothelial junctions showed a striking polarity of dye movement, with dye transfer from endothelial to smooth muscle cells but little or no transfer in the reverse direction. Because the dyes have size and charge characteristics similar to those of known cellular second messengers, these findings have important implications for cell-cell signaling in the vessel wall.

Animals↗

PubMed1995

Excessive insulin receptor serine phosphorylation in cultured fibroblasts and in skeletal muscle. A potential mechanism for insulin resistance in the polycystic ovary syndrome.

We investigated the cellular mechanisms of the unique disorder of insulin action found in the polycystic ovary syndrome (PCOS). Approximately 50% of PCOS women (PCOS-Ser) had a significant increase in insulin-independent beta-subunit [32P]phosphate incorporation (3.7-fold, P < 0.05 vs other groups) in skin fibroblast insulin receptors that was present in serine residues while insulin-induced tyrosine phosphorylation was decreased (both P < 0.05 vs other groups). PCOS skeletal muscle insulin receptors had the same abnormal phosphorylation pattern. The remaining PCOS women (PCOS-n1) had basal and insulin-stimulated receptor autophosphorylation similar to control. Phosphorylation of the artificial substrate poly GLU4:TYR1 by the PCOS-Ser insulin receptors was significantly decreased (P < 0.05) compared to control and PCOS-n1 receptors. The factor responsible for excessive serine phosphorylation appeared to be extrinsic to the receptor since no insulin receptor gene mutations were identified, immunoprecipitation before autophosphorylation corrected the phosphorylation defect and control insulin receptors mixed with lectin eluates from affected PCOS fibroblasts displayed increased serine phosphorylation. Our findings suggest that increased insulin receptor serine phosphorylation decreases its protein tyrosine kinase activity and is one mechanism for the post-binding defect in insulin action characteristic of PCOS.

Adult↗

PubMed1995

[Cytogenetic analysis of four cases of hermaphroditism].

On the basis of cytogenetics karyotype analysis, southern blot hybridization using sex-determining region of the Y chromosome (SRY) probe and amplified cation of the genomic DNA between the SRY code region by specific primers through polymerase chain reaction (PCR) have been performed in four cases of hermaphroditism. The results showed that, in 1 46, XY female and 1 45, XO/46, XY female, the SRY specific hybridization band and PCR amplified band could not be detected; in 1 46, XX male, the specific hybridization and PCR band showed SRY gene as in normal male; in another true hermaphrodite, the karyotype is 46, XX/47,XXY, PCR band is detectable but not hybridization band. The mechanism of the abnormal sex differentiation of the cases was analyzed and the two detection methods were compared.

Adult↗

PubMed1995

[Processing of pyritum from different sources].

Studies on the processing of Pyritum from different source were conducted by means of indentical technological procedure using total sulphur, S,FeS2 and Fe7S8 as indexes. The results showed considerable differences in compositions of the processed products.

Hot Temperature↗

PubMed1995

DNA content and morphological parameters in synovial sarcoma and synovioma.

By using image analysis technique with 6 normal synovial tissue specimens as controls, nuclear DNA content and morphological parameters in specimens from 51 synovial sarcomas and 15 synovioma were examined quantitatively. The DNA content in synovial sarcoma and synovioma was significantly different (P < 0.01), and that of synovioma and normal synovial tissue was also different (P < 0.05). Morphological parameters including nuclear areas and perimeters differed significantly among the above three groups (P < 0.01). There was no correlation between the DNA content of synovial sarcoma and its histologic type (P > 0.05), but the DNA content greatly differed between its higher and lower differentiated grade in each type (P < 0.01). The DNA content in synovial sarcoma IIA stage, according to Enneking's staging system was lower than that in IIB, IIIA and IIIB (P < 0.05). The 5-year survival rate of synovial sarcoma with diploid/nearly diploid (D/ND) pattern was higher than that of aneuploid (AN) pattern (P = 0.028). The study suggests that analysis of the DNA content and morphological parameters of tumor cells is helpful in the diagnosis and pathologic grading of synovial sarcoma. It also provides a guide to clinical operation and estimation of the prognosis. Although synovioma is usually a well-differentiated and benign lesion, this investigation also suggested that increased DNA content may be an indication of poor prognosis for this neoplasm.

Adolescent↗

PubMed1995

[Study on the retrofascial space of the dorsum nasi and its clinical significance].

Fifty-seven adult and two children cadavers were dissected to study the position, size and structure of the retrofascial space of the dorsum nasi. The space lay between the periosteum, perichondrium and the fascia dorsum nasi. The shape of the space is like a pyramid. The space averaged 3.09 +/- 0.66 cm in length. The anatomical characteristics, individual variation and clinical significance of this space were discussed.

Adult↗

PubMed1994

Structural characterization of an Ascaris myoglobin.

Globin was purified from the body wall of adults of the parasitic nematode Ascaris suum. Internal peptide fragments were sequenced and cDNAs encoding a polypeptide of 154 amino acids isolated by polymerase chain reaction. The polypeptide lacks a signal sequence, identifying it as a cytosolic myoglobin-like species. The native protein is a dimer. The predicted amino acid sequence shares several unusual substitutions with other nematode globins. Like the abundant pseudocoelomic A. suum hemoglobin it has a Tyr at B10 and a Gln at E7, substitutions thought to be determinants of high affinity. However, the 10-fold lower oxygen affinity of body wall globin suggests that in this molecule Tyr(B10) does not form an additional hydrogen bond with the heme bound oxygen. Evolutionary analysis of the nematode globins suggests that the monodomain myoglobin-like molecules and the two-domain hemoglobin-like molecules diverged about 500 million years ago, well before the divergence of the ascarid genera Ascaris and Pseudoterranova. The absence of introns in the A. suum myoglobin, in contrast to other nematode globin genes, is consistent with the hypothesis that during evolution intron elimination was the predominant event.

Amino Acid Sequence↗

PubMed1994

Disruption of sphingolipid metabolism and stimulation of DNA synthesis by fumonisin B1. A molecular mechanism for carcinogenesis associated with Fusarium moniliforme.

Consumption of grains contaminated with Fusarium moniliforme (Sheldon) causes liver cancer in rats and has been correlated with esophageal cancer in humans. The causative agents are believed to be a family of compounds known as fumonisins, which bear remarkable structural resemblances to sphingosine and sphinganine, the long-chain (sphingoid) base backbones of sphingolipids. Recently, fumonisin B1 has been shown to block de novo synthesis of sphingolipids by inhibiting sphingosine (sphinganine) N-acyltransferase, which leads to accumulation of sphingoid bases. Because the exogenous addition of sphingosine and sphingosine 1-phosphate to Swiss 3T3 cells has been shown to stimulate DNA synthesis (Zhang, H., Buckley, N.E., Gibson, K., and Spiegel, S. (1990) J. Biol. Chem. 265, 76-81; Zhang, H., Desai, N.N., Olivera, A., Seki, T., Brooker, G., and Spiegel, S. (1991) J. Cell Biol. 114, 155-167), we hypothesized that fumonisins might stimulate DNA synthesis by disrupting sphingolipid metabolism. Fumonisin B1 caused accumulation of sphinganine and sphingosine in Swiss 3T3 fibroblasts and, as occurred when these sphingoid bases were added exogenously, stimulated thymidine incorporation into DNA and augmented the mitogenic effect of insulin in a concentration-dependent manner. The mechanism underlying the mitogenic effect of fumonisin B1 was further investigated by using beta-fluoroalanine to block the initial step of sphingolipid biosynthesis catalyzed by serine palmitoyltransferase. beta-Fluoroalanine reduced sphingoid base accumulation in fumonisin B1-treated fibroblasts and inhibited fumonisin B1-stimulated DNA synthesis, but had no effect on mitogenesis when added alone. Fumonisin B1 did not cause accumulation of sphinganine 1-phosphate; therefore, it appears that sphingoid bases per se can stimulate DNA synthesis. To prove that the 1-phosphate is not obligatory, a 1-deoxysphinganine was synthesized, and it was as potent as sphinganine in stimulating DNA synthesis. These results establish that fumonisin B1 is mitogenic via accumulation of sphingoid bases rather than inhibition of complex sphingolipid biosynthesis per se. Because mitogens can often affect cell transformation, this provides a plausible molecular mechanism to explain the carcinogenicity of fumonisins.

3T3 Cells↗