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J Huang

Publications and source records attributed to J Huang.

At least 379 records · Page 21Linked to original sources
PubMed1999

The components of an inorganic physiological buffer for Penaeus chinensis.

Shrimp Penaeus chinensis, 5--8 cm in body-length were held in laboratory aquaria after collection from culture ponds at Laoshan in Qingdao in 1992. The osmotic pressure and the concentration of inorganic components of hemolymph in the shrimp were measured. The optimum pH and osmolarity of the buffer were determined from tests on primary cultures of hepatopancreatocytes in vitro. The results indicate that the hemolymph is homoiosmotic to 27 ppt seawater at 870 mOsm/L; osmotic regulation of shrimp is strong in low-salinity seawater, but weak in high-salinity seawater; the concentration of Mg(2+) ions in hemolymph is much less than that in seawater, while [K(+)] and [Ca(2+)] are much higher; hepatopancreatocytes in vitro have optimal survival at osmolarity range of 780-1, 100 mOsm/L and pH 6.5. Accordingly, an inorganic physiological buffer for P. chinensis (PPB, Penaeid Physiological Buffer) was prepared and contains NaCl, 23.0 g/L; K(2)SO(4), 1.1 g/L; CaCl(2), 1.6 g/L; MgSO(4).7H(2)O, 1.6 g/L; NaH(2)PO(4).2H(2)O, 0.35 g/L; NaHCO(3), 0. 05 g/L; pH 6.5; osmolarity, 867.9 mOsm/L. For storage of PPB, 4 stock buffers are made: 1) 10x PPB-A, which contains 230 g/L NaCl, 11 g/L K(2)SO(4), and 3.5 g/L NaH(2)PO(4).2H(2)O; 2) 40x PPB-B, which contains 64 g/L MgSO(4).7H(2)O; 3) 40x PPB-C, which contains 64 g/L CaCl(2); and 4) 100x PPB-D, which contains 50 g/L NaHCO(2). In order to increase the buffering capacity, PPB may be modified (to His-PPB), in which 5 g/L Histidine.HCl is used as the buffer reagent in place of NaH(2)PO(4) and NaHCO(3).

Animals↗
PubMed1999

The importance of clarithromycin dose in the management of Helicobacter pylori infection: a meta-analysis of triple therapies with a proton pump inhibitor, clarithromycin and amoxycillin or metronidazole.

BACKGROUND: It is not clear which dose of clarithromycin (500 mg b.d. or 250 mg b.d.) is more effective for Helicobacter pylori eradication in proton pump inhibitor-based triple therapies. METHODS: We undertook a meta-analysis of the effect of 7-day triple therapies consisting of a proton pump inhibitor (P), and clarithromycin (C) and amoxycillin (A) or metronidazole (M). A meta-analysis of all clinical trials performed in an adult population and published in English up to March 1998 was undertaken. Studies with doses of clarithromycin 500 mg b.d. or 250 mg b.d. only were included. RESULTS: A total of 82 studies (31 papers and 51 abstracts) involving 110 treatment arms and 6123 patients were analysed that met the predetermined inclusion and exclusion criteria. In the PAC combination, the pooled eradication rate in patients treated with clarithromycin 500 mg b.d. was 89.5% (95% CI: 86.9-92. 0%) by per protocol analysis and 86.6% (95% CI: 81.0-89.3%) by intention-to-treat analysis. These rates are significantly higher than those achieved with clarithromycin 250 mg b.d. (83.3% by per protocol and 78.2% by intention-to-treat analysis, both P < 0.0001). This difference was confirmed in head-to-head comparative studies. In the PMC regimen, clarithromycin 500 mg b.d. eradicated 90.8% (95% CI: 87.0-94.5%) of the infections compared to 88.5% (95% CI: 85.5-91. 5%) in patients treated with clarithromycin 250 mg b.d. by per protocol analysis (P = 0.082). The corresponding rates by intention-to-treat analysis for clarithromycin 500 mg b.d. and 250 mg b.d. was 88.3% and 86.7%, respectively (P = 0.259). CONCLUSIONS: Seven-day triple therapies with a proton pump inhibitor, clarithromycin and amoxycillin or metronidazole are highly effective treatments for the eradication of H. pylori. Clarithromycin 500 mg b. d. should be used in these combinations to achieve the best first treatment results, which can minimize the subsequent development of bacterial resistance to clarithromycin and metronidazole.

Adult↗
PubMed1999

Existence of multiple novel Gs alpha splice variants in acute leukemia patients.

The alpha subunit of the stimulatory G protein, Gs alpha, is involved in stimulation of the adenylate cyclase pathway of signal transduction. In this study, we investigated the status of the Gs alpha gene in 29 acute leukemia patients and identified three novel splice variants (designated Gs alpha L-1, Gs alpha L-2, and Gs alpha L-3), possibly derived from aberrant splicing. All of the splice variants have in-frame deletions, removing the functional domain responsible for GTPase activity of Gs alpha, and would encode truncated proteins of 160(Gs alpha L-1), 90(Gs alpha L-2) and 70(Gs alpha L-3) amino acids, respectively. The data suggest that these novel products may be implicated in an as-yet-unidentified signal transduction pathway in hematopoietic cells.

Acute Disease↗
PubMed1999

Linkage detection adaptive to linkage disequilibrium: the disequilibrium maximum-likelihood-binomial test for affected-sibship data.

It has been demonstrated in the literature that the transmission/disequilibrium test (TDT) has higher power than the affected-sib-pair (ASP) mean test when linkage disequilibrium (LD) is strong but that the mean test has higher power when LD is weak. Thus, for ASP data, it seems clear that the TDT should be used when LD is strong but that the mean test or other linkage tests should be used when LD is weak or absent. However, in practice, it may be difficult to follow such a guideline, because the extent of LD is often unknown. Even with a highly dense genetic-marker map, in which some markers should be located near the disease-predisposing mutation, strong LD is not inevitable. Besides the genetic distance, LD is also affected by many factors, such as the allelic heterogeneity at the disease locus, the initial LD, the allelic frequencies at both disease locus and marker locus, and the age of the mutation. Therefore, it is of interest to develop methods that are adaptive to the extent of LD. In this report, we propose a disequilibrium maximum-binomial-likelihood (DMLB) test that incorporates LD in the maximum-binomial-likelihood (MLB) test. Examination of the corresponding score statistics shows that this method adaptively combines two sources of information: (a) the identity-by-descent (IBD) sharing score, which is informative for linkage regardless of the existence of LD, and (b) the contrast between allele-specific IBD sharing score, which is informative for linkage only in the presence of LD. For ASP data, the proposed test has higher power than either the TDT or the mean test when the extent of LD ranges from moderate to strong. Only when LD is very weak or absent is the DMLB slightly less powerful than the mean test; in such cases, the TDT has essentially no power to detect linkage. Therefore, the DMLB test is an interesting approach to linkage detection when the extent of LD is unknown.

Alleles↗
PubMed1999

Selective binding of thyrotropin receptor autoantibodies to recombinant extracellular domain of thyrotropin/lutropin-chorionic gonadotropin receptor chimeric proteins.

The extracellular domain of the glycosylated human thyrotropin receptor (ET-gp) contains epitopes that can adsorb pathogenic antibodies from sera of patients with Graves' disease (GD). In an attempt to define the regions within the ETSHR with which autoantibodies interact, we expressed extracellular domains of eight thyrotropin receptor/chorionic gonadotropin receptor (TSHR/LH-CGR) chimeric proteins in insect cells. The levels of expression were high and chimeric proteins were glycosylated. Chimeric proteins designated as EMc2+4 and EMc2+3+4, in which amino acids (aa) 90-165 and 261-370, and aa 90-370, respectively, of TSHR were replaced with corresponding aa of LH-CGR, partially reversed the thyrotropin binding inhibitory immunoglobulin (TBII) activity of experimental anti-TSHR antisera (anti-ET-gp). The other six chimeras almost completely reversed the TBII activity of these anti-ET-GP antisera. Next, we tested the ability of these chimeric proteins to reverse the TBII activity of GD patients' sera. Similar to our earlier study, ET-gp protein reversed the TBII activity of all eight GD patients' sera tested. Chimera EMc2, in which aa 90-165 of TSHR has been replaced with corresponding aa of LH-CGR, and EMc2+4 partially reversed the TBII activity of only three of the eight GD patients' sera. However, the other six chimeric proteins failed to neutralize the TBII activity of any of GD patients' sera. These data showed the following: (1) There is considerable heterogeneity amongst autoantibodies in GD patients' sera, (2) The TBII activity of some, but not others, is dependent on aa 90-165 and 261-370, and (3) Most Graves' sera, with TBII activity, failed to react with chimeric proteins in which either N-terminal or C-terminal regions of the extra cellular domain of the TSHR were replaced with corresponding regions of LH-CGR. These results suggest that the TBII activity of GD patients' sera is dependent on conformational epitopes and replacement of certain regions of TSHR with homologous regions of LH-CGR results in sufficient alteration in the conformation of the protein leading to loss of reactivity.

Animals↗
PubMed1999

Titration of postischemic cerebral hypoperfusion by variation of ischemic severity in a murine model of stroke.

OBJECTIVE: Murine models using intraluminal occluding sutures to establish transient focal cerebral ischemia are becoming increasingly widespread, because of advances in transgenic technology and the advent of cerebroprotective strategies to ameliorate postischemic cerebrovascular no-reflow. We hypothesize that the degree of postischemic hypoperfusion is directly related to the severity of the initial ischemic insult. METHODS: Transient ischemia of 45-minute duration was produced using middle cerebral artery occlusion with 10-0 (n = 5), 9-0 (n = 5), 8-0 (n = 6), 7-0 (n = 8), 6-0 (n = 30), or 5-0 (n = 5) sutures. In separate experiments, transient vessel occlusion with 6-0 sutures was performed for 15 (n = 17), 30 (n = 16), or 45 (n = 30) minutes. Sequential laser Doppler measurements of relative cerebral blood flow were obtained, and stroke severity was assessed using neurological deficit scores and infarction volumes. RESULTS: Although relative cerebral blood flow at the time of occlusion and 24 hours thereafter was diminished in parallel with increasing suture diameters, only the use of larger sutures resulted in postischemic no-reflow. As the suture diameter was increased, the resultant reflow was decreased and the stroke outcome worsened. A more than twofold increase in infarction volume (8.0 +/- 3 versus 19.7 +/- 3%, P < 0.05) resulted when ischemia duration was increased from 30 to 45 minutes. CONCLUSION: Titration of the initial ischemic insult leads to corresponding variations in the magnitude of postischemic no-reflow and tissue damage. Therefore, critical control of the severity of the initial injury in studies using intraluminal suture occlusion is warranted.

Animals↗
PubMed1999

Safety and efficacy of fixed-dose heparin in carotid endarterectomy.

OBJECTIVE: Although fixed dosage of heparin is frequently used during vascular surgery, there are very few studies that document the appropriateness of this type of dosing. We have undertaken a prospective study to determine the physiological response to a fixed dose of heparin, using a conventional measure of anticoagulation, and have correlated this measure with complications. METHODS: We studied 140 consecutive patients undergoing elective carotid endarterectomy. Serial activated clotting times (ACT values) were obtained in duplicate before administration of heparin, 15 minutes after application of a carotid artery cross-clamp, and 1 hour after administration of 5000 U of heparin by intravenous bolus. Postoperatively, patients were assessed for new neurological deficits (transient ischemic attack and stroke) and neck hematomas. A battery of neuropsychometric tests was performed in 49 patients at baseline and on the day after carotid endarterectomy to identify subtle new neurological deficits. RESULTS: ACT values were found to be highly reproducible, with less than a 1.5% difference between duplicate baseline samples. Although all patients received 5000 U of heparin, the dose received per kilogram of body weight varied considerably (44-116 U/kg), as did ACT values at both 15 minutes (178-423 s) and 1 hour (173-390 s). Nevertheless, there was a significant correlation between heparin dose per kilogram and ACT values at 15 minutes (r = 0.45) and at 1 hour (r = 0.38) postinfusion, as well as ACT ratios (final ACT/initial ACT) at 15 minutes (r = 0.43) and at 1 hour (r = 0.34) after heparin bolus. Eight patients (5.7%) developed postoperative wound hematomas, one of which (0.7%) required reoperation. No patient had a stroke, but one patient had a transient ischemic attack, and 19 (39%) of 49 patients demonstrated significant early postoperative neuropsychometric deficits. Although the incidence of neck hematoma was not influenced by the heparin dose (P = 0.23), the ACT value at 15 minutes (P = 0.71) or 1 hour (P = 0.61), or the ACT ratio (P = 0.68), the only severe hematoma requiring reoperation occurred when the maximal ACT value was more than 400 seconds. Although performance on neuropsychometric tests did not appear to be statistically influenced by heparin dosing, the ACT value, or the degree of ACT elevation, there was a trend for deficits to be associated with lower heparin doses. CONCLUSION: Fixed heparin dosing achieves safe and efficacious anticoagulation in the great majority of patients having carotid endarterectomy, with 5000 U expected to result in 15-minute and 1-hour ACT values of 175 to 425 seconds and 170 to 390 seconds, respectively. Although weight-based heparin dosing may reduce the incidence of subtle complications (hematoma formation or decline on neuropsychometric tests) and may result in more predictable 15-minute and 1-hour ACT values (85 U/kg; 225-375 and 200-340 s, respectively), no statistically compelling clinical advantage could be demonstrated. Therefore, either weight-based or fixed dosing is acceptable, with both obviating the need for routine pre-clamp ACT confirmation, thereby saving operative time and expense.

Adult↗
PubMed1999

Analysis of the bifurcation diagram of a hybrid bistable system with feedback controls of chaos.

Based on the dynamic equation of a hybrid bistable system with a delayed feedback, we have studied changes of the bifurcation diagram of its output oscillation under chaos suppression and delayed feedback control of chaos, respectively, and the physical origin of these changes. The result clearly shows that, in this case, the input intensity of the system is replaced by a smaller effective input intensity. So the bifurcation diagram is shifted to its right side, and a certain part of the chaotic oscillation becomes periodic oscillation.

Journal Article↗
PubMed1999

Spatio-temporal tracking of myocardial deformations with a 4-D B-spline model from tagged MRI.

Accurate delineation of the volumetric motion of the left ventricle (LV) of the heart from tagged magnetic resonance imaging (MRI) is an important area of research. We have built a system that takes extracted tag line features from short axis (SA) and long axis (LA) image sequences as input and fits a four-dimensional (4-D) time-varying B-spline model to the data by simultaneously fitting the model knot solids to MRI frames via matching three sequences of solid knot planes to the LV tag planes for 4-D tracking. Important advantages of the model are that reconstruction of tag surfaces, three-dimensional (3-D) material point localization, as well as displacement reconstruction are all achieved in a single step. The generated 3-D displacement fields are validated with a cardiac motion simulator, and 3-D motion fields capturing in vivo deformations in a porcine model with posterolateral myocardial infarction are illustrated.

Animals↗
PubMed1999

Cloning, characterization, and expression of a novel gene encoding a reversible 4-hydroxybenzoate decarboxylase from Clostridium hydroxybenzoicum.

A novel gene, designated ohb1, which encodes the oxygen-sensitive and biotin-, ATP-, thiamin-, pyridoxal phosphate-, and metal-ion-independent, reversible 4-hydroxybenzoate decarboxylase (4-HOB-DC) from the obligate anaerobe Clostridium hydroxybenzoicum JW/Z-1(T) was sequenced (GenBank accession no. AF128880) and expressed. The 1,440-bp open reading frame (ORF) (ohb1) encodes 480 amino acids. Major properties of the heterologous enzyme (Ohb1) expressed in Escherichia coli DH5alpha were the same as those described for the native 4-HOB-DC (Z. He and J. Wiegel, J. Bacteriol. 178:3539-3543, 1996). The deduced amino acid sequence shows up to 57% identity and up to 74% similarity to hypothetical proteins deduced from ORFs in genomes from bacteria and archaea, suggesting a possible novel gene family.

Base Sequence↗
PubMed1999

Production and characterization of a soluble, active form of Tva, the subgroup A avian sarcoma and leukosis virus receptor.

The receptor for the subgroup A avian sarcoma and leukosis viruses [ASLV(A)] is the cellular glycoprotein Tva. A soluble form of Tva, sTva, was produced and purified with a baculovirus expression system. Using this system, 7 to 10 mg of purified sTva per liter of cultured Sf9 cells was obtained. Characterization of the carbohydrate modification of sTva revealed that the three N glycosylation sites in sTva were differentially utilized; however, the O glycosylation common to Tva produced in mammalian and avian cells was not observed. Purified sTva demonstrates significant biological activity, specifically blocking infection of avian cells by ASLV(A) with a 90% inhibitory concentration of approximately 25 pM. A quantitative enzyme-linked immunosorbent assay, developed to assess the binding of sTva to ASLV envelope glycoprotein, demonstrates that sTva has a high affinity for EnvA, with an apparent dissociation constant of approximately 0.3 nM. Once they are bound, a very stable complex is formed between EnvA and sTva, with an estimated complex half-life of 6 h. The soluble receptor protein described here represents a valuable tool for analysis of the receptor-envelope glycoprotein interaction and for structural analysis of Tva.

Alpharetrovirus↗
PubMed1999

Association of oestrogen receptor gene polymorphisms with age at onset of rheumatoid arthritis.

OBJECTIVE: In view of the possible role of oestrogens in the pathogenesis of rheumatoid arthritis (RA), this study investigated the association between oestrogen receptor (OR) gene polymorphisms and RA. METHODS: Pvu II and Xba I restriction fragment length polymorphisms of the OR gene were analysed in 70 male and 240 female patients with RA, and in 300 male and 350 female controls. The absence or presence of restriction sites were represented as P, p (Pvu II) or X, x (Xba I). The distribution of OR genotypes was compared between the RA and control subjects by sex. RA patients were divided into subgroups according to their OR genotypes, then the age at onset, seropositivity, and rheumatoid nodule positivity were compared between the subgroups. RESULTS: The OR genotype frequency of distribution did not have significant differences between the male RA and male controls nor between the female RA and female controls. In women with RA, there was a significant difference of age at onset between the subgroups (uncorrected p = 0.047, corrected p = 0.94). Female patients with the OR genotype PPxx (homozygote of Px) tended to have developed RA at a younger age, whereas those with PPXX and ppxx (lack of Px haplotype) developed RA at an older age. In men with RA, there was no association between the OR genotype and age at onset. In seropositivity and rheumatoid nodule positivity, there was no significant difference between subgroups for either sex. CONCLUSIONS: Some variants of the OR gene are related to the onset of RA in women in certain age periods, suggesting the role of the interaction between the OR gene and serum concentrations of oestrogen at the onset of the disease.

Adult↗
PubMed1999

Clinical findings and outcomes of intra-hemodialysis cardiopulmonary resuscitation.

Renal failure with severe uremia is still an important cause of mortality, despite effective renal replacement therapy. Cardiopulmonary arrest (CPA) is the most severe complication during hemodialysis (HD). To acquire more information about cardiopulmonary resuscitation (CPR) during HD, we retrospectively enrolled 24 patients (11 males and 13 females) who had CPR during HD in a medical center during a 3-year period. Their mean age was 66.8 +/- 16.8 years. The CPR rate of the patients from our outpatient department (0.02%) was significantly lower than that from general wards (0.11%), the intensive care unit (ICU, 0.16%), or the emergency room (ER, 0.38%). Eighteen patients (75%) were initially resuscitated successfully. Only 11 patients (45.8%) survived more than 24 h after CPR, and 2 patients (8.3%) survived more than 1 month, but none survived until discharge. The rates of surviving 24 h and surviving to discharge during HD were lower than those in the general wards, the ICU or the ER. Sepsis (33.3%) and cardiogenic shock (25%) were the two leading causes of death. For analyzing factors affecting the outcome of CPR, we divided the patients into 2 groups by survival time (<==24 vs. >24 h). Patients with heart disease or with prolonged CPR durations (>30 min) had shorter survival. No significant survival difference between the 2 groups was found due to factors of age, sex, diabetic nephropathy, pre-arrest morbidity scores, pre-arrest laboratory data, renal failure pattern, HD duration, the preceding HD time and ultrafiltrated volume.

Aged↗
PubMed1999

Correlation between the in vivo efficacy of GPIIb/IIIa receptor antagonists (m7E3, MK-383 and DMP-728) and ex vivo platelet inhibition.

In vivo antithrombotic efficacy of GPIIb/IIIa receptor antagonists (m7E3, MK-383 and DMP-728) was studied with respect to their ex vivo platelet inhibition in heparinized platelet-rich plasma (hPRP) and citrated platelet-rich plasma (cPRP) using a canine model of carotid artery thrombosis. For each drug group (n = 6), the right carotid artery was used as control vessel and resulting occlusive thrombus was kept in situ to examine the direct thrombolytic efficacy of the antagonists. Thirty minutes after occlusion of control vessel, a low or high dose of each antagonist was administered and the left carotid artery was used as test vessel. All control vessels occluded within 86-96 min in response to electrolytic injury. The incidence of occlusion with lower doses of m7E3, DMP-728, and MK-383 was 100, 33 and 100%, respectively; corresponding times to occlusion were 174, 220 and 118 min. Lower doses inhibited ADP- or AA-induced platelet aggregation in cPRP (>80%). Incidence of occlusion with high doses of m7E3, DMP-728 and MK-383 was 33, 0 and 0%, respectively; corresponding times to occlusion were 209, >240 and >240 min. Higher doses inhibited aggregation in cPRP (>80%), but only partially in hPRP (45-66%). Dose-dependent prolongation of bleeding time occurred with all antagonists. None of the antagonists lyzed preformed thrombi in control vessels. The results indicate that ex vivo platelet aggregation conducted in hPRP, as opposed to conventional cPRP, provides a better assessment of the in vivo efficacy of GPIIb/IIIa receptor antagonists.

Adenosine Diphosphate↗
PubMed1999

Significant reductions in length of stay after carotid endarterectomy can be safely accomplished without modifying either anesthetic technique or postoperative ICU monitoring.

BACKGROUND AND PURPOSE: We sought to determine whether postoperative length of stay (LOS) and resource utilization could be safely reduced without changing our uniform protocol of performing carotid endarterectomy (CEA) under general anesthesia with postoperative intensive care unit monitoring. METHODS: We retrospectively reviewed the hospital records of 421 consecutive CEA operations performed during a 3-year period of transition in discharge policy to determine LOS, complications, and resource utilization. We divided operated patients into 3 cohorts: cohort I patients were operated on before a stay reduction policy was instituted (1995, n=171); cohort II patients were operated on after the institution of a single-day-stay policy for selected patients (January to August 1996, n=95); and cohort III patients were operated on after the institution of a universal single-day-stay policy (September 1996 to December 1997, n=155). RESULTS: While significant in-hospital complications leading to increased LOS remained essentially unchanged over time (cohort I: 4.0%; II: 6.3%; III: 3.9%; P=NS), the mean postoperative LOS decreased from 2.6+/-0.3 days in cohort I to 1.6+/-0.1 days in cohort III (P<0.0001). The median postoperative LOS also decreased from 2 days to 1 day from cohort I to III, with 70% of patients discharged after 1 day in cohort III compared with only 32% for cohort I (P<0.0001). In addition, the total number of laboratory studies ordered decreased from 8.0+/-0.8 per patient in cohort I to 6.4+/-0.5 in cohort III (P<0.01). CONCLUSIONS: A uniform policy of discharge home from the intensive care unit on postoperative day 1 following CEA under general anesthesia can reduce LOS and decrease resource utilization without compromising care.

Adult↗
PubMed1999

Enhanced proteoglycan deposition in the airway wall of atopic asthmatics.

Increased extracellular matrix (ECM) deposition in the airway wall contributes to the airway wall remodeling observed in asthmatics. Although alterations in collagen have been well described, less is known about changes in other components of the ECM, particularly proteoglycans (PGs). Endobronchial biopsies were obtained from seven patients with mild atopic asthma and six normal control subjects. Tissues were blocked in OCT and frozen in isopentane. Sections were immunostained with antibodies for the small leucine-rich PGs, lumican, biglycan, decorin, and fibromodulin and for versican, a large chondroitin sulfate PG. We calculated the area of positive staining in the subepithelial layer, correcting for basement membrane length. Lumican, biglycan, and versican were localized predominantly in the subepithelial layer of the airway wall in all groups. PG deposition was significantly increased in asthmatics as compared with that in control subjects. Furthermore, the degree of PG immunoreactivity was significantly correlated with airway responsiveness in the asthmatics (lumican; r = -0.77, p < 0.05; biglycan: r = -0.76, p < 0.05; versican: r = -0.74, p = 0.06). Our results suggest that PGs may play a role in airway wall remodeling and thereby, airway mechanics in asthma.

Asthma↗