Search PubMed⌕ Search

Biomedical subjects

Z S Huang

Publications and source records attributed to Z S Huang.

At least 19 recordsLinked to original sources
PubMed2001

Peripheral differential leukocyte counts in humans vary with hyperlipidemia, smoking, and body mass index.

Reports of diverse relationships between blood concentrations of different lipids and peripheral total leukocyte count, and a unique lower peripheral monocyte count in hypercholesterolemia, have driven us to think that in humans, peripheral differential leukocyte counts may be influenced differently by different types of hyperlipidemia. Our subjects were Taipei residents who attended a regular health check program in our hospital in 1998. A total of 3,282 subjects was enrolled, including 1,677 normolipidemic, 960 untreated borderline hyperlipidemic, and 645 untreated hyperlipidemic subjects. By one-way analysis of variance (ANOVA), we found that different types of hyperlipidemia were associated with significant differences in differential leukocyte counts. In hypertriglyceridemia, the total leukocyte count and counts of all leukocyte subtypes were significantly higher than those in normolipidemia. Pure hypercholesterolemia, by contrast, was associated with a significantly lower monocyte count and no significant difference in other leukocyte counts. By two-way ANOVA adjusted for presence and degree of hyperlipidemia, we found significantly higher counts of total leukocytes and of all leukocyte subtypes in smokers, and significantly positive trends in relationships between body mass index (BMI) and counts of all leukocytes, neutrophils, lymphocytes, and monocytes. By multivariate regression analysis including all subjects, the serum triglyceride (TG) level was positively correlated with total leukocyte count and counts of all subtypes except eosinophils. On the contrary, serum high density lipoprotein-cholesterol had a negative correlation with total leukocyte count and with counts of neutrophils, monocytes, and basophils. In these multivariate regression analyses, there was no significant correlation between lipid levels and eosinophil count, whereas smoking was consistently associated with significantly higher counts of all leukocyte subtypes, including eosinophils. BMI had a significantly positive correlation with counts of all leukocytes, neutrophils, lymphocytes, and monocytes.

Body Mass Index↗
PubMed2001

Correlations between peripheral differential leukocyte counts and carotid atherosclerosis in non-smokers.

Substantial evidence clearly indicates the immuno-inflammatory nature of atherosclerosis and the important roles of monocytes and other leukocytes in atherogenesis. The relationship between atherosclerosis and the peripheral monocyte count, however, has been equivocal and uncertain so far. One possible reason may be an opposing effect of different major risk factors of atherosclerosis on the monocyte count, e.g. smoking increases the monocyte count while hypercholesterolemia is accompanied by a lower monocyte count. Since smoking is well shown to increase leukocyte counts prominently in weeks, our study included only non-smokers who participated in a health check program at our hospital from 1996 to 1998 and had received a carotid duplex study with extra payment. Our results revealed the followings: In male non-smokers (n=571), the presence of carotid atherosclerosis was associated with significant increases in the counts of all leukocyte, neutrophil, and monocyte (P<0.005,<0.001 and <0.05, respectively), and, after adjustments for age and body mass index, there were significant positive links between these three leukocyte counts and the severity of carotid atherosclerosis, judged by either the sum score of all carotid plaques or the score of the most severe carotid plaque. On the contrary, in female non-smokers (n=614), there was no significant link between differential leukocyte counts and either the presence or severity of carotid atherosclerosis. These results are compatible with recently recognized sex differences in the mechanism and pathophysiology of atherosclerosis, and together with relevant results in the literature, suggest that monocytes and neutrophils are the main types of leukocytes involved in atherosclerosis.

Adult↗
PubMed2000

Serum level of soluble tumor necrosis factor receptor II (sTNF-R75) is apparently an index of overall monocyte-related infectious and inflammatory activity.

BACKGROUND: The serum level of soluble tumor necrosis factor receptor II (sTNF-R75) has been recently found to correlate with the activity and/or severity of several different infectious and inflammatory diseases. These results have led us to presume that the serum sTNF-R75 level reflects the active immune activity of all causes and may correlate well with nonspecific infectious and inflammatory markers such as peripheral leukocyte counts and serum C-reactive protein level. METHODS: In total, 110 apparently healthy adults, 55 men and 55 women, were enrolled in the study. Serum levels of sTNF-R75, C-reactive protein, globulin, alkaline phosphatase, lactate dehydrogenase, creatinine, urea nitrogen, and counts of neutrophils, lymphocytes, monocytes, eosinophils, and basophils were checked. The relationships between the serum sTNF-R75 level and other parameters were analyzed using the SAS statistical program. RESULTS: By various statistical methods, the serum sTNF-R75 level showed consistently significant positive links with peripheral monocyte count, serum C-reactive protein level, and two parameters of renal clearance function (serum urea nitrogen and creatinine levels). Serum levels of alkaline phosphatase and lactate dehydrogenase had significant positive links with the serum sTNF-R75 level by multivariate regression analysis. There was no significant link between the serum sTNF-R75 level and counts of neutrophils, lymphocytes, eosinophils, or basophils. CONCLUSIONS: Our results, together with those of recent reports showing positive correlations between the serum sTNF-R75 level and activities/severities of different infectious and inflammatory diseases, and also that TNF-alpha is principally produced by monocytes and macrophages, suggest that the serum sTNF-R75 level is very probably an index of overall monocyte-related infectious and inflammatory activities.

Adult↗
PubMed1998

Identification and characterization of the RNA chaperone activity of hepatitis delta antigen peptides.

In this study, we identified an activity of the hepatitis delta antigen that both modulates the cis-cleaving activities of hepatitis delta virus (HDV) genomic RNA fragments and facilitates the trans-cleavage reactions between hammerhead ribozymes and the cognate substrates of various lengths in vitro. Hepatitis delta antigen peptides exert their effect by accelerating the unfolding and refolding of RNA molecules and by promoting strand annealing and strand dissociation. In addition, the stimulatory effect of hepatitis delta antigen peptide on hammerhead catalysis is observed whether the peptide is removed or not by phenol/chloroform extraction prior to the initiation of trans-cleavage reaction. Therefore, hepatitis delta antigen peptide acts as an RNA chaperone. The RNA chaperone domain of hepatitis delta antigen overlaps with the coiled-coil domain that is rich in lysine residues. The RNA binding domains of hepatitis delta antigen previously identified are not required for the RNA chaperone activity identified herein. The RNA chaperone activity of hepatitis delta antigen may be important for the regulation of HDV replication in vivo.

Amino Acid Sequence↗
PubMed1998

Subtypes and case-fatality rates of stroke: a hospital-based stroke registry in Taiwan (SCAN-IV).

Stroke data bank can afford important information regarding risk factors, pathogenesis, prognosis, etc. By means of hospital-based stroke registry, we investigated the risk factors and case-fatality rates in different types of stroke and transient ischemic attack (TIA) patients at the National Taiwan University Hospital in 1995. After excluding ineligible patients, 995 patients aged 1-98 years (575 men and 420 women) were recruited. Men predominated in all age groups for stroke and TIA in general except for cerebral hemorrhage (CH) in patients aged < 35 years and subarachnoid hemorrhage (SAH) in patients aged > or = 45 years. Of these, 676 (67.9%), 41 (4.1%), 228 (22.9%) and 50 (5%) patients were classified in the categories of cerebral infarction (CI), TIA, CH and SAH, respectively. The CI/CH ratio was 2.96. Hypertension remained one of the most important risk factors for CI, CH and TIA patients. Severe extracranial carotid artery stenosis (> or = 50%) was found in 12% of the CI patients and 27% of the TIA patients, but not found in the CH and SAH patients. Of these patients, the 30-day case-fatality rate was 10.9%, highest in SAH (30%), followed by CH (24.1%) and CI (5.6%). There were 41 in-hospital stroke patients who had significantly higher case-fatality rates than the other stroke patients (P<0.001 for all stroke, CI and CH patients by chi2 test). As compared to the previous stroke registries in Taiwan, there is a secular trend of increasing CI/CH ratios. These findings in Taiwan were compared with those in other populations, including other Asian, Caucasian and black populations. The CI/CH ratios in Asian populations, including Chinese, Japanese and Korean, were much lower than those in Caucasian and black populations. Dietary, environmental and genetic factors probably play important roles in these differences.

Adolescent↗
PubMed1998

Localization of TIMP-1, TIMP-2, TIMP-3, gelatinase A and gelatinase B in pathological human corneas.

PURPOSE: Determine the tissue distribution patterns for tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, TIMP-3), gelatinase A and gelatinase B in normal and pathologic corneas. METHODS: Corneas were examined by immunohistochemistry, using antibodies to TIMP-1, TIMP-2, TIMP-3, gelatinase A or gelatinase B. RESULTS: In normal corneas, TIMP-1 antibody stained the epithelium and endothelium. TIMP-2 and TIMP-3 stained the epithelium, keratocytes and endothelium. Gelatinase A staining was weak and restricted to the epithelial cells. Radial keratotomy scars showed increased staining for TIMP-1 and TIMP-2 around the epithelial cell plug and along the incision. Bullous keratopathy corneas showed TIMP staining patterns similar to normal corneas and increased gelatinase A staining in regions of subepithelial fibrosis. Stromal scars of keratoconus corneas also had increased staining with TIMP-1 and TIMP-2 antibodies. In many keratoconus corneas, the TIMP-3 staining pattern was similar to normal corneas. However, in some keratoconus corneas, when Bowman's layer was missing, the stroma beneath was completely devoid of TIMP-3 antibody staining. No gelatinase B was seen in either the normal or diseased corneas. CONCLUSION: These data suggest that TIMP-1 and TIMP-2 are important for scar formation and corneal remodeling, since they were found in increased amounts at radial keratotomy incision sites and keratoconus scars. The significance of the focal stromal defects in TIMP-3 staining, associated with absence of Bowman's layer on keratoconus corneas, needs to be elucidated. At the stages of disease examined in this study, gelatinase B may not play a significant role in these pathological processes, since it was not seen in any of the corneas examined.

Base Sequence↗
PubMed1998

Human corneal epithelial basement membrane and integrin alterations in diabetes and diabetic retinopathy.

Corneas of diabetic patients have abnormal healing and epithelial adhesion, which may be due to alterations of the corneal extracellular matrix (ECM) and basement membrane (BM). To identify such alterations, various ECM and BM components and integrin receptors were studied by immunofluorescence on sections of normal and diabetic human corneas. Age-matched corneas from 15 normal subjects, 10 diabetics without diabetic retinopathy (DR), and 12 diabetics with DR were used. In DR corneas, the composition of the central epithelial BM was markedly altered, compared to normal or non-DR diabetic corneas. In most cases the staining for entactin/nidogen and for chains of laminin-1 (alpha1beta1gamma1) and laminin-10 (alpha5beta1gamma1 was very weak, discontinuous, or absent over large areas. Other BM components displayed less frequent changes. The staining for alpha3beta1 (VLA-3) laminin binding integrin was also weak and discontinuous in DR corneal epithelium. Components of stromal ECM remained unchanged even in DR corneas. Therefore, distinct changes were identified in the composition of the epithelial BM in DR corneas. They may be due to increased degradation or decreased synthesis of BM components and related integrins. These alterations may directly contribute to the epithelial adhesion and wound healing abnormalities found in diabetic corneas.

Adult↗
PubMed1997

An AU at the first base pair of helix 3 elevates the catalytic activity of hepatitis delta virus ribozymes.

A mutational analysis of the helix 3 (H3) region of hepatitis delta virus (HDV) ribozymes disclosed that an AU at the first base pair of H3 elevates the catalytic activity of various cis- and trans-acting HDV ribozymes. A GC to AU substitution at this position of H3, which is located at the junction of three of the four helices of the pseudoknot-like structure model, altered the structure of HDV ribozymes. This substitution in the H3 did not change the independence of the cleavage rate to pH nor the sensitivity to formamide treatment of the ribozymes.

Base Sequence↗
PubMed1997

Effectiveness of low-dose ASA in prevention of secondary ischemic stroke, the ASA Study Group in Taiwan.

This randomized double-blind controlled study was carried out to investigate the effect of 100 mg acetylsalicylic acid (ASA) per day on the secondary prevention of ischemic stroke. Patients who suffered a first ischemic stroke from 13 participating hospitals were enrolled. They were independent or only partially dependent in activities of daily living and all had received brain CT for diagnosis. Eligible patients were randomly allocated to the 100 mg ASA or the nicametate citrate (a vasodilator) groups, and trial medications were started within three to six weeks after the onset of stroke. The primary end point was cerebral reinfarction, and intracranial hemorrhage was classified as an adverse event. Four hundred and sixty-six patients participated in this study; and 222 cases (136 males and 86 females) were allocated to the ASA group while 244 cases (150 males and 94 females) were assigned to the nicametate group. No significant difference in baseline characteristics between the two groups was observed. Cerebral reinfarction developed 6.3% (14/222) in the ASA group and 11.9% (29/244) in the nicametate group. According to the Cox's proportional hazards model, the estimated risk ratio (ASA group vs. nicametate group) was 0.538, with a 95% confidence interval of 0.284-1.019. The result was of borderline statistical significance. The risk for cerebral reinfarction was reduced by almost 50% among those who took 100 mg ASA versus those who took nicametate.

Aged↗
PubMed1997

Subtypes of ischemic stroke. A hospital-based stroke registry in Taiwan (SCAN-IV).

BACKGROUND AND PURPOSE: To better understand the clinical pattern and further elucidate the risk factors and outcome in different subtypes of cerebral infarction (CI) of the Chinese in Taiwan, we analyzed the National Taiwan University Hospital Stroke Registry in 1995 and performed an ethnic comparison with similar data banks. METHODS: From the National Taiwan University Hospital Stroke Registry in 1995, 676 patients (383 men and 293 women; mean age, 64.9 years; SD, 13.8 years; range, 1 to 98 years) with CI were recruited for this analysis. CI was classified into five subtypes based on clinical manifestations, ultrasonographic studies, and neuroimaging findings: large-artery atherosclerosis, lacunae, cardioembolism, other less common determined causes, and undetermined cause. Vascular risk factors, extracranial carotid artery atherosclerosis, and 30-day case-fatality rates were investigated in each subtype of CI. RESULTS: Of all CI patients, 17%, 29%, 20%, 6%, and 29% were classified as large-artery atherosclerosis, lacunae, cardioembolism, other determined causes, and undetermined cause subtypes, respectively. The present results were compared with those from eight similar Western stroke registries. The relative incidence of lacunar CI in Chinese patients was more common, but large-artery atherosclerotic CI was less common than in whites. Hypertension was frequently seen in CI patients, especially in those with lacunae (85%) and large-artery atherosclerosis (69%). Patients with cardioembolism had a higher percentage of atrial fibrillation (69%), left ventricular hypertrophy, and ischemic heart disease than the other patients. Patients with large-artery atherosclerosis had more vascular risk factors, such as hypertension, diabetes mellitus, smoking, and carotid stenosis. Cardioembolic patients had higher case-fatality rates than other CI patients. Of the cardioembolic patients, 17.3% and 21.8% died within 30 days and during hospitalization, respectively. CONCLUSIONS: The proportion of CI subtypes varied in different stroke registries. This may be partly due to applied classification criteria and racial-ethnic differences. Awareness of the risk factors and outcome in each subtype of stroke may afford further insights into the surveillance and treatment of cerebrovascular disease.

Adolescent↗
PubMed1997

Stroke prevalence in Taiwan. Findings from the 1994 National Health Interview Survey.

BACKGROUND AND PURPOSE: Stroke has been the second leading cause of death for all ages in Taiwan since 1983. However, despite the severity of the threat, stroke prevalence in Taiwan has not yet been addressed in a nationwide survey. In this study, the stroke prevalence in Taiwan was investigated using data from the 1994 National Health Interview Survey. METHODS: This nationwide survey sought to obtain a nationally representative sample of households in Taiwan by using three-stage stratified random sampling with a probability proportional to size. In the first stage, 58 townships were selected, from the 359 townships in Taiwan, according to their administrative structure and level of socioeconomic development. In the second stage, 149 basic administrative regions (tsun or li) were selected from the selected 58 townships. Finally, 3814 households were selected from the 149 selected tsuns or lis. Field interviews were carried out between October 1994 and December 1994. Follow-up interviews with families of stroke patients were made 2 years later. RESULTS: Of the selected households 3119, or 81.8%, responded. A total of 11925 persons were interviewed, and 71 of them were stroke patients, with a crude point prevalence rate of 5.95 per 1000. The stroke prevalence increased steadily with age, from 0.51 per 1000 in persons aged 35 to 44 years to 113.6 per 1000 in persons aged 85 years or over. There was a weak association with higher stroke prevalence for persons living in eastern Taiwan or those of lower educational level. The overall male/female prevalence ratio was 1.17. The results of follow-up interviews showed a cumulative mortality rate of 25.4% within the 2-year period and an ischemic/hemorrhagic stroke ratio of 1.33 in 35 patients whose stroke type could be validated. CONCLUSIONS: Age was the most important factor correlating to stroke prevalence. On the basis of this result, planning policies and programs for stroke prevention in Taiwan should give a higher priority to (1) aggressive primary prevention for aged people who are apparently at higher risk of stroke and (2) early reduction of stroke risk factors in younger aged people whose immediate risk of stroke is lower but would increase significantly with age.

Adult↗
PubMed1997

[Studies on improving the ability of learning and memories of yangshoudan].

OBJECTIVE: To observe the effects of Yangshoudan(YSD) on the ability of learning and memories in experimental animals. METHODS: The tests of darkness-avoidance response in normal young mice and rats, aged mice, as well as in model mice with dysmnesia induced by anisodine, model rats with dysmnesia induced by scopolamine hydrobromide and with orientation disturbance induced by pentobarbital sodium. RESULTS: In normal young mice and rats, the error times in five minutes in learning and memories tests was reduced (P < 0.01-0.05) by YSD, while in dysmnesia groups the error times in five minutes also reduced (P < 0.01-0.05) and the incubation period of memories could be shortened by YSD. In orientation disturbance mice, the averages and percentages of correct response times increased by YSD. CONCLUSIONS: YSD could improve the memory ability both in normal and dysmnesia which either induced by drugs or due to age. This indicates primarily that YSD has the effects of improving the ability of learning and memories and of antidementia.

Animals↗
PubMed1997

Stimulation of locus coeruleus increases arterial pressure in rabbits.

AIM: To study the effect of electric and chemical stimulation of locus coeruleus (LC) on arterial pressure and renal sympathetic nerve discharge activity (RSA). METHODS: Electric stimulation of LC and microinjection of L-glutamate (L-Glu), morphine, and GABA into the LC of rabbits were made. The LC was destructed electrolytically. Arterial pressure and RSA were recorded. RESULTS: Both electric stimulation (150 microA, 50 Hz) of the LC and microinjection of L-Glu (0.5 mumol) into unilateral LC elicited increases in arterial pressure (13.5 +/- 0.3 vs 19.5 +/- 0.8 kPa, P < 0.01 and 13.8 +/- 0.4 vs 17.5 +/- 0.8 kPa, P < 0.01, respectively) and RSA (by 107 +/- 14%, P < 0.01, and 88 +/- 21%, P < 0.01, respectively). Microinjection of morphine or GABA did not induce any significant changes in the above two parameters. Electrolytic lesion of the LC eliminated the pressor response induced by microinjection of L-Glu. CONCLUSION: Excitation of LC has a pressor effect in rabbits, but LC is not a crucial nucleus in tonic regulation of blood pressure.

Animals↗
PubMed1997

[Electrophysiological study of the relationship between rostral ventrolateral medulla and locus coeruleus of rabbits].

The electrophysiological characteristics of locus coeruleus (LC) neurons and the projection from the rostral ventrolateral medulla (RVLM) to the LC were investigated on 18 rabbits, which were lightly anesthetized, decerebelated, paralyzed and artificially ventilated. 93 of the 108 recorded LC neurons are firing spontaneously at about 5.1 Hz, while the remaining are silent but could be activated by pinching. 64 (59.2%) of the LC neurons manifested excitatory response to brushing and 93 (86.1%) to pinching. Of the 108 LC neurons, 85 (78.7%) neurons could be activated orthodromically by ipsilateral RVLM stimulation with a latency of 21.6 +/- 6.9 ms, among which 67 neurons showed excitatory response. 35 of the 123 recorded RVLM neurons responded antidromically to ipsilateral LC stimulation with a latency of 19.2 +/- 8.2 ms. These results suggest that there may exist a direct excitatory pathway from RVLM to LC.

Animals↗
PubMed1997

[Activation of locus coeruleus inhibits vagal inputs in nucleus tractus solitarius].

On pentobarbital anesthetized rabbits, a three-wavelet compound potential to cervical vagal afferent stimulation was recorded in ipsilateral nucleus tractus solitarius (NTS). The latency of the three wavelets (P1, P2 and P3) was 6.8 +/- 0.6 ms (P1), 25.8 +/- 4.2 ms (P2) and 89.1 +/- 2.7 ms (P3) respectively, which might represent postsynaptic activity of different kinds of vagal afferent fibers. Microinjection of glutamate into ipsilateral locus coeruleus (LC) decreased the amplitude of P2 and P3 significantly. Electrical stimulation of LC could activate 111 units in ipsilateral NTS with a mean latency of 6.3 +/- 1.4 ms. Of the 169 units in the NTS to vagal afferent stimulation, 90 units also responded to LC stimulation. 39 (43.3%) of the ninety, units shows similar response to both stimuli, while the rest show different response. Of the 25 units which showed excitatory response to both LC and vagal stimulation, but when LC stimulation was followed by vagus stimulation, the latter's response was either markedly suppressed (14 units) or completely inhibited (11 units). These results showed that activation of LC exerts an inhibitory effect on the responses of the NTS to vagal afferent stimulation.

Afferent Pathways↗
PubMed1996

The importance of the helix 2 region for the cis-cleaving and trans-cleaving activities of hepatitis delta virus ribozymes.

The sequence, secondary structure, and size requirements of the helix 2 region (H2) of a cis-acting hepatitis delta virus ribozyme Rz 1 were examined in this study. Mutational analysis was performed, and the cleavage rate of each H2 mutant of Rz 1 was assayed. We found that H2 could be elongated to twice its original size without affecting ribozyme folding while the shortening of H2 by one base pair severely decreased autolytic activity. In addition, the maintenance of the Watson-Crick base-pairing interactions of the last base pair of H2 (A16U58) was not critical for cis-cleavage reaction. Nevertheless, mutants with an AA, an AG, an AC, or a GG pair at the bottom of H2 were less active, and the sequence of the H2/H3 interface might affect the stability of the catalytic core. The negative effects on ribozyme folding, such as the destabilization of H2, the unfavorable sequences at the last base pair of H2 as well as the disruption of the continuity of H2 and H3, could be compensated for by elongating the H2 region of the corresponding mutants. The extension of H2 may alter the conformation of ribozyme molecules; in addition, it stabilized the catalytic core and enhanced the resistance to formamide. Finally, for a trans-acting ribozyme and its substrate that require the formation of H1, H2, and H4 to reconstitute the autocatalytic domain of HDV RNA, the extension of H2 stabilized the substrate/ribozyme complex and speeded up the cleavage rate but hindered the product release process.

Base Sequence↗
PubMed1996

In hypercholesterolemia, lower peripheral monocyte count is unique among the major predictors of atherosclerosis.

Many studies have shown that enhanced monocyte adherence is an important factor in the initiation of atherosclerosis. Because the relationships between circulating monocyte count and atherosclerosis or its major predictors have received little attention, we conducted this study with the aim of clarifying these relationships. The study included 409 men and women who underwent a carotid artery duplex study and white blood cell analysis (Sysmex Cell Counter) during a 2-day health check at our hospital in 1994. We found no correlation between preexisting carotid atherosclerosis and monocyte count. After adjustment for age and sex, hypercholesterolemia, among the major predictors of atherosclerosis, showed a unique correlation with both lower monocyte count and percentage (P < .001, P < .0001, respectively), whereas smoking was correlated with a higher monocyte count (P < .001). There was a slight but nonsignificant increase in monocyte count in hypertension, diabetes, and hypertriglyceridemia. Our results imply that: (1) hypercholesterolemia has a strong, peripheral monocyte-reducing effect, probably due to direct enhancement of monocyte adhesion to the endothelium, which subsequently initiates the atherosclerotic process, and (2) the mechanisms of other predictor(s)-induced atherosclerosis may be quite different from that of hypercholesterolemia. Another possible explanation for the inverse correlation between monocyte count and serum cholesterol level is that decreased monocyte levels might lead to hypercholesterolemia because of decreased uptake of cholesterol from the plasma by less monocyte-derived macrophages. The reasons why preexisting carotid atherosclerosis did not correlate with monocyte count are also discussed.

Arteriosclerosis↗