Biomedical subjects

P He

Publications and source records attributed to P He.

At least 91 records · Page 5Linked to original sources

PubMed1999

Chlorpromazine inhibits hepatocyte apoptosis caused by withdrawal of phenobarbital in mice.

AIM: To study the inhibitory effect of chlorpromazine (Chl), verapamil, and aspirin on hepatocyte apoptosis induced by the cessation of phenobarbital (Phe) treatment in mice. METHODS: Liver DNA content, ratio of liver weight/body weight, DNA fragmentation, DNA electrophoresis, the end-labeling test (TUNEL), and the morphologic changes of liver cells as indices of liver mass and hepatocyte apoptosis were applied to investigate (1) the kinetic process of hepatocyte proliferation induced by Phe 75 mg.kg-1 i.p. and the regression of hyperplastic liver caused by withdrawal of Phe in mice, (2) the effect of Chl 25 mg.kg-1, verapamil 50 mg.kg-1 or aspirin 60 mg.kg-1 i.p. on mouse hepatocyte apoptosis, and (3) the time course of effects of Chl on the regression of liver size and DNA fragmentation content after withdrawal of Phe. RESULTS: The process of hepatocyte proliferation and regression induced by administration and withdrawal of Phe in mice consisted of 4 phases: proliferation, plateau, rapid regression, and slow regression phases. In the rapid regression phase, the typic changes of hepatocyte apoptosis were found, which was prevented in early period by the Ca(2+)-calmodulin antagonist Chl, but not by verapamil or aspirin. CONCLUSION: The Ca(2+)-calmodulin played an important role in the hepatocyte apoptosis caused by withdrawal of Phe.

Animals↗

PubMed1999

[Telemedicine--technology, application, evaluation and prospect].

With the information society drawing near, the pattern of medical treatment is changing. Telemedicine is now carrying out many purposes such as family health care, first aid, expert consultation, long-distance intervene and learning communication in it's particular mode. This article will enter into some engineering-technology methods of medical information transmission (including data, sound and image), introduce several application field of telemedicine , evaluate the potential benefit, virtue and some problems which are likely to arise in the implement of telemedicine, and forecast the development of telemedicine in the future.

Aerospace Medicine↗

PubMed1999

Structure and function of alleles in the 3' end region of human apoB gene.

OBJECTIVE: To study the structure of alleles in the 3' end of the apoB gene in Han, Mongolian and Tibetan populations in China as well as the roles in the regulation of gene expression. METHODS: DNA were obtained from human leukocytes by phenol-chloroform extraction and ethanol precipitation. PCR were carried out in a 50 microliters volume containing 50 ng genomic DNA as template. The Ssp1-digested products were loaded on a gradient acrylamide gel and run for 3 hours. The constructs containing alleles were tested in cultured HepG2 and HeLa cells using transient assays. RESULTS: Sixteen alleles with different repeat number were characterized. All of the alleles varying from HVE22 to HVE52, allele HVE34 was the most common (58.4%), followed by allele HVE36 (13.8%) and HVE32 (10.5%). 258 PCR products were digested with Ssp1 and run in 4-12% PAGE. We detected the fragments of 266bp, 91 bp, 61 bp and 39 bp in almost all samples. The small alleles (including HVE22, HVE24, HVE26 and HVE36) decreased the expressive activity of the luciferase reporter, in contrary, the large alleles (including HVE44, HVE46 and HVE48) elevated obviously the expressive activity of the luciferase reporter. CONCLUSIONS: More alleles with different number of tandem repeats in 3' end of apoB gene exist in the Chinese populations. The alleles in 3' end minisatellite of human apoB gene could control the expression of the gene itself.

Alleles↗

PubMed1998

cGMP modulates basal and activated microvessel permeability independently of [Ca2+]i.

To investigate the mechanisms whereby guanosine 3',5'-cyclic monophosphate (cGMP) modulates microvessel permeability in vivo, we measured changes in microvessel hydraulic conductivity (Lp) and endothelial cytoplasmic Ca2+ concentration ([Ca2+]i) in response to the cGMP analogs 8-bromo-cGMP (8-BrcGMP) and 8-(p-chlorophenylthio)cGMP (8-pCPT-cGMP) in the presence and absence of inflammatory stimuli in intact individually perfused microvessels in frog and rat mesenteries. The cGMP analog caused a transient increase in Lp and potentiated ATP or bradykinin-induced increases in Lp in frog and rat mesenteric microvessels, respectively. The mean peak value of the test Lp/control Lp after exposure to 8-BrcGMP was 5.3 +/- 0.5 in frog microvessels and 2.8 +/- 0.4 in rat microvessels. The ATP-induced increase in Lp in frog microvessels was further raised by 8-BrcGMP from 7.0 +/- 0.9 to 12.4 +/- 1.9 times the control. In rat mesenteric microvessels, the bradykinin-induced increase in Lp was potentiated by 8-BrcGMP from 4.8 +/- 0.4 to 8.3 +/- 1.3 times the control and was suppressed by the guanylate cyclase inhibitor LY-83583 to 2.6 +/- 0.5 times the control. A similar but larger effect was found when using 8-pCPT-cGMP. In contrast to the actions of increased cGMP on microvessel permeability, cGMP analogs had no effect on basal endothelial [Ca2+]i and did not alter the magnitude and time course of ATP or bradykinin-induced increases in endothelial [Ca2+]i. These results suggested that an elevation of cGMP levels in endothelial cells is a necessary step to increase microvessel permeability in intact microvessels, and this regulatory process occurs downstream from Ca2+ influx, which differs from that reported in large-vessel endothelium in culture and in vascular smooth muscle cells. Experiments carried on microvessels in both frog and rat mesenteries provided a direct comparison of the endothelial cell regulatory mechanisms between species.

Adenosine Triphosphate↗

PubMed1998

Determination of ultrasonic parameters based on attenuation and dispersion measurements.

In the measurement of acoustic attenuation that obeys a power-low alpha = beta f, the traditional through-transmission method uses only the amplitude information of the recorded pulses to determine the two parameters, beta and n. In this paper, we propose a new method that utilizes both the amplitude and phase information of the pulses to determine the two parameters. According to this method, the two parameters are estimated by simultaneously performing a least squares fit to the attenuation data that are derived from the amplitude spectra of the pulses, and to the dispersion data that are derived from the phase spectra of the pulses. By fully utilizing the information contained in the recorded pulses and imposing additional constraints on the two parameters, the estimation uncertainty can be reduced. Experimental results from two specimens, one having a linear attenuation and one having a nonlinear attenuation, demonstrate that the new method produces a moderate variance reduction in the case of linear attenuation, and a significant variance reduction in the case of nonlinear attenuation.

Castor Oil↗

PubMed1998

Hypoglycemic effect of water-soluble polysaccharide from Auricularia auricula-judae Quel. on genetically diabetic KK-Ay mice.

The hypoglycemic effect of water-soluble polysaccharide(FA) from fruiting bodies of Auricularia auricula-judae Quel. was investigated on genetically diabetic mice (KK-Ay) from 10 to 14 weeks of age. Male mice were divided into 3 groups, the control group and FA-fed group having free access to the control diet or FA diet (30 g of FA/kg of diet). The food-restricted group had restricted access to the control diet at the level of the diet consumed by the FA-fed group. Compared with the control group, FA supplementation had a significant effect in lowering plasma glucose, insulin, urinary glucose, and food intake. FA administration also increased the tolerance to intraperitoneal glucose loading and the hepatic glycogen content. In the food-restricted group, the reduced food intake slightly lowered the plasma and urinary glucose levels, but did not improve hyperinsulinemia and glucose tolerance. This study shows that FA had a hypoglycemic effect on KK-Ay mice, and the reduced food consumption was not a major factor which contributed to the hypoglycemic action of FA.

Agaricales↗

PubMed1998

Green tea suppresses D-galactosamine-induced liver injury in rats.

Dietary supplementation with powder of a green tea extract suppressed the enhancement of plasma alanine aminotransferase and aspartate aminotransferase activities induced by D-galactosamine, but not by carbon tetrachloride, in a dose-dependent manner in rats. The minimum dose to cause a significant effect was 1 to 2%. Drinking green tea also suppressed plasma enzyme activities. These results indicate that green tea had a liver injury-preventive effect.

Alanine Transaminase↗

PubMed1998

Ameliorating effects of water-soluble polysaccharides from woody ear (Auricularia auricula-judae Quel.) in genetically diabetic KK-Ay mice.

We investigated the ameliorating effects of the three groups of water-soluble polysaccharides, a mixture of crude polysaccharides (FA), acidic polysaccharide fractions (FA-A), and neutral polysaccharide fractions (FA-N), obtained from the hot water extracts of the fruit bodies of Auricularia auricula-judae Quel. In genetically diabetic KK-Ay mice from 6 to 11 weeks of age. Male mice were divided into five dietary groups: 1) control group, given a basal diet; 2) FA group, given an FA diet (15 g FA/kg diet); 3) FA-A group, given an FA-A diet (8 g FA-A/kg diet); 4) low FA-N group, given a low FA-N diet (2 g FA-N/kg diet); and 5) high FA-N group, given a high FA-N diet (8 g FA-N/kg diet). Compared with the control diet, FA supplementation had significant effects in lowering fasting and nonfasting blood glucose, HbA1c, urinary glucose, food intake, and water intake. FA administration also improved glucose tolerance to intraperitoneal glucose loading, but it did not affect the nonfasting insulin level. FA-N supplementation had dose-dependent effects in lowering fasting and nonfasting food glucose, insulin, HbA1c, urinary glucose, food intake, and water intake. However, the glucose tolerance was not ameliorated by either the low or the high FA-N diet. FA-A administration showed no beneficial effects in KK-Ay mice.

Agaricales↗

PubMed1998

Induction of hepatocyte proliferation and prevention of hepatocyte apoptosis by phenobarbital related to local humoral factor in mouse liver.

AIM: To study the association of phenobarbital (Phe) inducing hepatocyte proliferation and blocking hepatocyte apoptosis with local humoral factor in liver. METHODS: The ratio of liver/body weight, DNA content, regressive rate of hyperplastic liver, and DNA fragmentation were used to investigate whether the Phe-treated mouse liver extract (PMLE) and PMLE-95 (PMLE heated at 95 degrees C for 30 min) possessed Phe-like effects on mouse liver. Meantime, the effects of pretreatment with trypsin, RNAase, and DNAase on the activity of PMLE-95 were observed, and the differences of components between PMLE-95 and NMLE-95 (normal mouse liver extract, NMLE heated at 95 degrees C for 30 min) were analyzed with HPLC. RESULTS: PMLE-95 stimulated hepatocyte proliferation and prevented hepatocyte apoptosis caused by withdrawing Phe in mice, and the activity of PMLE-95 was eliminated after the pretreatment with trypsin. On the chromatograms PMLE-95 had 5 main peaks, while NMLE-95 had only 4 peaks. CONCLUSION: The effects of Phe on the liver were mediated by an intrinsic protein or peptide substance produced in response for the stimulation of Phe in mouse liver.

Animals↗

PubMed1998

[The use of predforte in the transnasal endoscopic sinus surgery].

For finding a way to advance the healing of the operative cavity after transnasal endoscopic sinus surgery (TESS). Predforte (mixt 10% prednisolone acetate) was administered transnasally to the operative cavity of 75 cases who accepted TESS. 13 cases (17.5%) were brought about a striking effect, the good results were achieved on the 56 cases. The total effective rate was 92.0%. The results suggest that the mixture could be distributed better and effected longer in comparison with the solution of predinisolone acetate.

Adolescent↗

PubMed1998

[Diagnosis and treatment of duodenal injury].

OBJECTIVE: To increase the value of early diagnosis and decrease postoperative complications of duodenal injury. METHOD: 16 patients with duodenal injury were treated and 5 patients were treated successfully with Modified Cogbill's techniques. RESULT: We emphasized the importance of early diagnosis and treatment of duodenal injury. CONCLUSION: The simplified techniques produce less complications and considered to be used clinically application.

Abdominal Injuries↗

PubMed1998

[A probe into the relationship between spasmodic dysphonia and laryngeal paralysis].

OBJECTIVE: To investigate into the relationship between spasmodic dysphonia and laryngeal paralysis. METHODS: The intrinsic laryngeal muscle potential was recorded with electromyography. Vocal cord movements were observed with a videostroboscope. Laryngeal paralysis was divided into mild, moderate, and severe degrees based on the potentials of intrinsic laryngeal muscles and on the status of vocal cord movements. RESULTS: In the past 12 years (from 1983 to 1994) 1300 cases were diagnosed as having mild, moderate, and severe laryngeal paralysis. Among them, there were 5 cases with laryngospasm including 3 mild, 1 moderate, and 1 severe case. CONCLUSION: The findings obtained from careful observation on these 5 cases of spasmodic dysphonia demonstrated that there existed certain relationships between laryngeal paralysis and spasmodic dysphonia. During the course of exacerbation or restoration of paralysis, spasmodic dysphonia might occur.

Adult↗

PubMed1997

In vitro transcription of the Leptomonas seymouri SL RNA and U2 snRNA genes using homologous cell extracts.

A cell-free transcription system for the spliced leader (SL) RNA gene of the trypanosomatid Leptomonas seymouri has been developed. Accurately initiated transcription was achieved using cell extracts and a template in which the transcribed region of the SL RNA was replaced with a guanosine-less sequence (G-less cassette). The extract was also able to direct accurate initiation of RNA from an L. seymouri tagged U2 snRNA gene, which may be expressed via a transcriptional apparatus shared by the SL RNA gene. In vivo transcription analysis was used previously to define essential sequence components of the SL RNA gene promoter (Hartree D, Bellofatto V. Mol Biochem Parasitol 1995:71:27-39). A substitution mutation in the upstream promoter element (bp - 50 to - 70) markedly reduced transcription in vitro as did deletion of this and the middle promoter element (bp - 30 to - 40). Thus, the in vitro transcription system correctly responds to promoter mutations and is useful for investigating SL RNA and snRNA gene expression.

Animals↗

PubMed1997

N-Ethylmaleimide-sensitive fusion protein contains high and low affinity ATP-binding sites that are functionally distinct.

N-Ethylmaleimide-sensitive factor (NSF) has been shown to be involved in numerous intracellular membrane fusion events of both the regulated and constitutive secretory pathways. Sequence analysis indicates that the NSF subunit contains two nucleotide-binding sites, both with the classical Walker A and B motifs. In this report, we examine the nucleotide binding properties of NSF. The homotrimer contains three high affinity ATP-binding sites with Kd = 30-40 nM for ATP and Kd = 2 microM for ADP. This class of binding sites did not bind AMP, adenine, or GTP. A second class of lower affinity nucleotide binding sites with a Kd = 15-20 microM was also detected. Using various mutant forms of NSF, the high affinity nucleotide-binding sites were localized to the D2 domains and the low affinity sites were localized to the D1 domains. Functionally it is these lower affinity sites in D1 that are crucial for NSF activity. Nucleotide concentration greatly affected the ability of NSF to interact with alpha-SNAP.SNARE (soluble NSF attachment protein-SNAP receptor) complex, suggesting that only when the D1 domain ATP-binding sites are occupied does NSF bind to the alpha-SNAP.SNARE complex.

Adenosine Triphosphate↗

PubMed1997

Cloning and expression of angiotensin II type 2 (AT2) receptors from murine neuroblastoma N1E-115 cells: evidence for AT2 receptor heterogeneity.

Homology-based PCR was used to isolate angiotensin II type 2 (AT2) receptor cDNA from murine neuroblastoma N1E-115 cells. Despite subtle differences in the nucleotide sequence (the N1E-115 clone coded for Phe133 as TTC and Gln326 as CAG; base substitutions are in bold-italics), the AT2 receptor protein was identical to other reported murine AT2 clones. When transfected into COS-1 cells, the expressed AT2 receptor displayed high affinity for AngII and for AT2-selective compounds, GTP gamma S-insensitive agonist binding and enhanced agonist binding by dithiothreitol. Previously, we have demonstrated that N1E-115 cells possess two distinct subpopulations of AT2 receptors, defined as peak I and peak III receptors, that can be separated by heparin-sepharose chromatography. The two subpopulations differ pharmacologically, biochemically and immunologically. The binding properties of the cloned AT2 receptor closely resembled that of peak III receptors. Moreover, antisera raised against peak I AT2 receptors failed to immunoreact to either peak III receptors or cloned AT2 receptors expressed in COS-1 cells. Collectively, these data suggest that the cloned AT2 receptor is identical to peak III receptors from N1E-115 cells and that a novel AT2 receptor (peak I) remains to be cloned.

Angiotensin II↗

PubMed1997

Effect of nitric oxide synthase inhibitors on endothelial [Ca2+]i and microvessel permeability.

To investigate the mechanism whereby nitric oxide (NO) signaling pathways regulate microvessel permeability in vivo, we measured changes in microvessel hydraulic conductivity (Lp) and endothelial cytoplasmic calcium concentration ([Ca2+]i) in response to calcium ionophore, ionomycin (5 microM), and ATP (10 microM) before and after the use of NO synthase (NOS) inhibitors in single perfused frog mesenteric venular microvessels. Ionomycin induced a transient increase in endothelial [Ca2+]i and an associated increase in Lp. The NOS inhibitors N omega-nitro-L-arginine methyl ester (10 and 300 microM) and N omega-monomethyl-L-arginine (L-NMMA; 10, 50, and 100 microM) significantly attenuated the peak increase in Lp induced by ionomycin. A similar inhibitory effect was also observed with the increase in Lp mediated by ATP. In contrast, D-NMMA, a biologically inactive isomer of L-NMMA, showed no effect on ionomycin-induced increase in Lp L-Arginine (3 mM) reversed the inhibitory effect of L-NMMA (10 microM) on Lp. However, the NOS inhibitors did not alter the magnitude and time course of the biphasic increase in endothelial [Ca2+]i induced by both ionomycin and ATP. These data suggest that 1) calcium-dependent NO release is a necessary step to increase microvessel permeability, and 2) the action of NOS inhibitors in attenuating the permeability increase in response to ionomycin and ATP occurs down-stream from calcium entry and does not involve modification of the initial increase in endothelial [Ca2+]i.

Adenosine Triphosphate↗

PubMed1997

Effect of nitric oxide synthase inhibitors on basal microvessel permeability and endothelial cell [Ca2+]i.

We evaluated the role of basal nitric oxide (NO) release in the regulation of microvessel permeability under resting conditions. We measured changes in microvessel hydraulic conductivity (Lp) and endothelial cytoplasmic calcium concentration ([Ca2+]i) after application of NO synthase (NOS) inhibitors to the lumen of individually perfused frog mesenteric venular microvessels. NOS inhibitors caused a transient increase in Lp. The mean ratios of peak test Lp values relative to control values in the presence of N omega-nitro-L-arginine methyl ester (L-NAME) at concentrations of 1, 10, and 100 microM were 2.5 +/- 0.6, 2.9 +/- 0.7, and 4.8 +/- 0.4, respectively. N omega-monomethyl-L-arginine (L-NMMA) showed a similar effect and a biologically inactive isomer of L-NMMA, D-NMMA, showed no effect. These results demonstrate that basal levels of NO play a role in modulating microvessel permeability different from that due to NO produced in response to inflammatory agents. In the activated state NOS inhibitors attenuated the increased microvessel permeability in response to ionomycin and ATP [P. He, B. Liu, and F. E. Curry. Am. J. Physiol. 272 (Heart Circ. Physiol. 41): H176-H185, 1997]. The transient increase in basal permeability induced by NOS inhibitors was not accompanied by an increase in endothelial cell [Ca2+]i and did not require the presence of extracellular calcium. Application of ketotifen, a mast cell stabilizer, and an iron-chelating reagent, deferoxamine mesylate, attenuated the transient increase in Lp induced by L-NMMA, suggesting that basal NO may have an important antioxidant role in regulating normal permeability.

Animals↗

PubMed1997

Spatial compounding in 3D imaging of limbs.

Effects of spatial compounding on image resolution and speckle noise are studied. Using computer simulation, it is shown that spatial compounding using averaged reconstruction can significantly improve lateral resolution while slightly deteriorate axial resolution. The amount of net resolution improvement depends mainly on the compound angle, but is insensitive to the number of component images used in compounding. While the fact that spatial compounding can effectively reduce speckle noise is well known, the analysis in this paper indicates that to maximize speckle reduction, the component echo amplitudes must meet two conditions: to be mutually independent and to have the same mean power. These findings provide useful guidelines for the analysis and optimization of the performance of an ultrasound scanning system that has been specially developed for imaging residual limbs.

Artificial Limbs↗