Search PubMed⌕ Search

Biomedical subjects

W H Hu

Publications and source records attributed to W H Hu.

At least 73 records · Page 4Linked to original sources
PubMed1996

The effect of thrombolytic therapy on short- and long-term cardiac autonomic activity in patients with acute myocardial infarction.

BACKGROUND: Reduced heart rate variability after acute myocardial infarction is an important risk stratification factor for mortality and life threatening ventricular arrhythmias. In recent years, thrombolytic therapy has revolutionized the therapy of acute myocardial infarction. However, there is little information about the mechanism of the beneficial effect of thrombolysis on cardiovascular mortality. This study was launched to investigate the relationship between thrombolytic therapy and cardiac autonomic activity, and the sequential changes in heart rate variability after acute myocardial infarction. METHODS: From October 1994 to July 1995, all consecutive patients with their first acute myocardial infarction were prospectively enrolled into the study. Patients without contraindication underwent thrombolytic therapy within six hours of the onset of symptoms. Other patients received conventional treatment. Ambulatory electrocardiography (EKG) was recorded on each patient 7, 90 and 180 days after acute myocardial infarction. Heart rate variability in time- and frequency-domain was analyzed. RESULTS: A total of 49 patients, 45 males and 4 females, were included in this study. The short-term heart rate variability (HRV) (seven-day) in the thrombolytic group was significantly higher than in the nonthrombolytic group in SDANN and SDNN. No significant difference in rMSSD, pNN50, LF, HF or LF/HF ratio was found. The location of MI did not influence the short-term HRV following acute myocardial infarction. In patients treated with thrombolytic agent, the follow-up HRV at 90 days and 180 days increased significantly compared to the baseline HRV (seven-day) in SDANN, SDNN, LF and HF bands. For patients without thrombolytic therapy, their follow-up HRV at 90-day and 180-day increased significantly as compared to the baseline HRV (seven-day) in SDANN and SDNN only. After correction of ventricular ejection fraction, the higher short-term (seven day) HRV activities were still present in SDANN and SDNN in patients with thrombolysis as compared to those without. The 90-day and 180-day HRV did not differ between patients with and without thrombolytic agent. Three patients died suddenly during follow-up, and all showed significantly lower values of HRV than the survivors. CONCLUSIONS: The findings of the present study suggest that 1) in patients with uncomplicated AMI, HRV was transiently reduced with progressive improvement within three months after AMI in both those with and without thrombolytic therapy, and 2) patients who had received thrombolytic treatment had more improved HRV early (seven days) after AMI than those who did not. This improvement, independent of the change of left ventricular function, could be associated with the beneficial effect of thrombolytic therapy in patients with AMI.

Adult↗
PubMed1996

[Effects of NA and 5-HT on the spontaneous and evoked activities of Purkinje cells in cerebellar slice].

Effects of NA and 5-HT perfusion on the spontaneous activity and evoked responses of the Purkinje cells (PCs) to stimulation of white matter were studied in the rat cerebellar slices. The results were as follows: (1) Perfusion with NA could elicit inhibitory, excitatory or biphasic responses of the spontaneously discharging PCs, with inhibitory response in dominance (79.8%). 5-HT perfusion could also exert either excitatory or inhibitory effect on PC spontaneous activity. (2) When NA and 5-HT were perfused successively, NA tended to inhibit while 5-HT tended to excite in 53.8% of the tested cells. (3) Most of the complex spike (CS) and simple spike (SS) responses evoked by white matter stimulation could be potentiated by NA (68.2%, 57.1%) or depressed by 5-HT (60.0%, 68.2%). (4) On the same cell under successively perfusion with NA and 5-HT, the evoked CS and SS responses of most cells (60.0%, 52.9%) showed a tendency to be facilitated by NA and suppressed by 5-HT. These results suggest that aminergic afferent fibers, by releasing NA and 5-HT, may affect PC's excitability and responsiveness to synaptic inputs from mossy and climbing fibers, thus playing an important role in the cerebellar function.

Afferent Pathways↗
PubMed1995

Does coronary artery disease with stressed myocardial ischemia alter heart rate variability?

BACKGROUND: Research has shown that decreased heart rate variability (HRV) is independently associated with increased mortality after acute myocardial infarction. However, the relationship between HRV and myocardial ischemia still remains controversial. The purposes of this study were (1) to determine the relationship between HRV and atherosclerosis of the coronary artery; and (2) to determine the relationship between HRV and the extent of coronary stenosis in patients with stressed myocardial ischemia. METHODS: Forty-six patients, 41 males and 5 females, were included in this study. Ages ranged from 50 years to 79 years. Seventeen volunteers served as the control group, which was comprised of 15 males and 2 females of ages ranging from 40 years to 74 years. For each patient a left ventriculogram and a coronary angiogram were performed. According to their coronary angiograms, patients were divided into normal coronary artery group, atherosclerotic coronary artery group and significant coronary artery disease group. An ambulatory EKG was performed on each patient and volunteer. Heart rate variability was defined as SDNN, SDANN, rMSSD, and pNN50 in time domain measures; and low and high frequency in frequency domain measures. RESULTS: There were no significant differences in all variables of heart rate variability between the atherosclerotic coronary artery group and normal coronary artery group. In addition, there were no significant differences in all variables between the significant coronary artery disease group and the control group or between the significant coronary artery disease group and the normal coronary artery group. CONCLUSIONS: These studies have shown that atherosclerotic or significant coronary artery disease with stressed myocardial ischemia does not impair 24-hour heart rate variability.

Aged↗
PubMed1995

Haloperidol plasma concentrations in Taiwanese psychiatric patients.

Haloperidol and reduced haloperidol are interconverted. The plasma concentrations of these two butyrophenones have been suggested to be important factors in determining the clinical effect of haloperidol treatment. The steady-state plasma concentrations of haloperidol and reduced haloperidol were measured in 322 Taiwanese schizophrenic patients using high performance liquid chromatography. The daily doses of haloperidol varied from 5 to 200 mg (mean +/- SD, 35.3 +/- 34.6 mg). There was a positive correlation between plasma concentrations and doses, following the equation: haloperidol concentration (ng/mL) = 0.88 x dose (mg/day)-1.66. However, the interpatient variation in haloperidol concentrations was up to ten-fold even in patients receiving the same dose (20 mg/day, n = 88). The expected values were about 10% to 50% higher than those reported in Caucasian patients. The plasma reduced haloperidol concentrations were significantly lower than, and correlated with, those of haloperidol in patients with haloperidol levels lower than 25 ng/mL. However, once haloperidol exceeded 25 ng/mL, reduced haloperidol levels rapidly elevated and appeared significantly higher than haloperidol levels. While haloperidol could reach its steady state in about 1 week, reduced haloperidol needed at least 4 weeks to do so. Haloperidol doses of less than 30 mg/day and plasma concentrations lower than 25 ng/mL are recommended for most Chinese patients.

Adult↗
PubMed1995

Sucralfate in Helicobacter pylori eradication strategies.

BACKGROUND: Sucralfate monotherapy has been shown to suppress but not eradicate Helicobacter pylori. The combination of sucralfate with antibiotic(s) has been evaluated recently in the treatment of H. pylori-positive duodenal ulcer. The aim of this article is to review the efficacy of sucralfate-containing duotherapy and triple therapy in duodenal ulcer healing and H. pylori eradication rates. METHODS: Reports on duotherapy and triple therapy including sucralfate as the mediating agent were analysed to assess the duodenal ulcer healing and H. pylori eradication rates. RESULTS: One study on duotherapy with sucralfate and amoxycillin achieved an ulcer healing rate of 86% and H. pylori eradication rate of 40%, which compared favourably with sucralfate monotherapy that resulted in duodenal ulcer healing and H. pylori eradication rates of 65% and 0% respectively. A total of six studies have examined triple therapy using sucralfate with two antibiotics. The duodenal ulcer healing rates were generally over 90% and the H. pylori eradication rates about 80% (range 59% to 100%). In one comparative study, the 4-week duodenal ulcer healing and H. pylori eradication rates of sucralfate-containing triple therapy were not distinguishable from those of omeprazole-containing triple therapy. CONCLUSIONS: It is concluded that sucralfate is an effective mediating agent for the eradication of H. pylori in patients with duodenal ulcer.

Anti-Bacterial Agents↗
PubMed1995

Measurements of heart rate variability in patients with unexplained syncope.

BACKGROUND: Syncope is a common clinical issue with complex and heterogenous etiologies. Research has shown a large proportion of syncope remained unexplained, even after serial investigations. Head-up tilt test with or without isoproterenol infusion could elicit a recurrence in most patients with unexplained syncope. Therefore, autonomically neural-mediated bradycardia and hypotension have been cited as the mainstays of the mechanism. Since the autonomic function can be reflected by heart rate rariability, this study proposed to determine 24-hour heart rate variability in patients with unexplained syncope. METHODS: Fifteen patients, 14 males and 1 female, who were defined as showing symptoms of unexplained syncope, were the subjects of this study. Their ages ranged from 38 years to 79 years. Seventeen healthy volunteers matching in age and sex served as the control group. For each patient and volunteer, 24-hour ambulatory electrocardiographic monitoring was done. Heart rate variability was defined as SDNN index, SDNN, SDANN, rMSSD, and pNN50 in time domain measures; and low, high, and total frequency in frequency domain measures. RESULTS: There was a significantly lower value at low frequency, high frequency, total frequency, rMSSD, and pNN50 in the syncope group than in the control group (p < 0.05). There was no significant difference in SDNN, SDNN index, SDANN and LF/HF ratio between these two groups. CONCLUSIONS: Patients with unexplained syncope had autonomic withdrawal; this was the case either in both sympathetic and parasympathetic components without changing the sympatho-vagal balance, or in purely parasympathetic component.

Adult↗
PubMed1994

[Intrathecal co-administration of kappa opioid receptor agonists and NMDA receptor antagonists induces synergistic analgesia in rats].

It is reported that intrathecal (it) injection of low dose of dynorphin (Dyn) induces no analgesia while high dose of Dyn induces analgesia and might lead to hindlimb paralysis and loss of reflex via NMDA receptor. We hypothesized that NMDA receptor antagonists may reveal kappa analgesic-potential of subliminal dose of Dyn. Twenty-four hours after intrathecal cannulation, tail flick latency was measured before and after it of drugs. Combination of Dyn A- (1-13) 5 nmol or U50488H 100 nmol, a kappa receptor agonist with either DL-2-amino-5-phosphonovaleric acid (5 and 10 nmol) or kynurenic acid (25 and 50 nmol) it induced synergistic analgesia, which was reversed by nor-binaltorphimine 15 nmol, a kappa receptor antagonist. It is concluded that kappa opioid receptor agonists and NMDA receptor antagonists synergistically induce analgesia via interaction with their receptors.

2-Amino-5-phosphonovalerate↗
PubMed1993

Prolonged haloperidol and reduced haloperidol plasma concentrations after decanoate withdrawal.

Haloperidol and reduced haloperidol plasma concentrations were measured in twelve schizophrenic patients upon cessation of haloperidol decanoate (HLD) treatment. Each patient received HLD 100 mg every 4 weeks for five injections. After the fifth injection, HLD was discontinued. Haloperidol and reduced haloperidol plasma concentrations were obtained prior to cessation and at weeks 1, 3, 4, 5, 7, 9, 11, and 13 post-injection. Haloperidol and reduced haloperidol plasma concentrations were assayed by HPLC. Both haloperidol and reduced haloperidol plasma concentrations were detectable 13 weeks post HLD discontinuation. Maximal haloperidol plasma concentrations were observed at one week post cessation and gradually declined. The mean elimination half-life for haloperidol was 27.4 +/- 8.6 days (range 19.0-47.0 days). Reduced haloperidol plasma concentrations declined very slowly. Our results show that both haloperidol and reduced haloperidol plasma concentrations can remain for extended time periods after HLD is discontinued.

Adult↗
PubMed1993

Plasma homovanillic acid and treatment response in a large group of schizophrenic patients.

Plasma levels of homovanillic acid (pHVA), a metabolite of dopamine, were measured in ninety-five Chinese schizophrenic patients free of neuroleptics for at least four weeks. These patients were treated with classical antipsychotics for six weeks. Pretreatment pHVA was positively correlated with the subsequent clinical response (r = 0.408, p < 0.0001). Good responders (BPRS improvement > or = 50%, n = 47) had higher pretreatment pHVA levels than poor responders (BPRS improvement < 50%, n = 48) (15.7 +/- 8.4 ng/ml versus 9.9 +/- 3.7 ng/ml, p < 0.0001). A higher than 15 ng/ml pretreatment pHVA level was associated with a more consistent clinical response to the subsequent treatment. Using a pHVA level of 12 ng/ml as a demarcation point, 72% of patients (34 of 47) who had pHVA > or = 12 responded whereas 65% (31 of 48) who had < 12 did not respond (chi-square = 13.02, p < 0.0001). These results suggest that higher pretreatment pHVA levels may predict a better clinical response to antipsychotics. Based upon the pHVA findings, two hypothetical subtypes of schizophrenia are proposed.

Adolescent↗
PubMed1993

Reduced haloperidol/haloperidol ratios after oral haloperidol and decanoate administration in schizophrenics.

1. Haloperidol and reduced haloperidol plasma concentrations were measured in thirteen stable schizophrenic patients that received both oral haloperidol and haloperidol decanoate. 2. Significant correlations between reduced haloperidol/haloperidol ratios from oral haloperidol and haloperidol decanoate occurred at week two and week 16, respectively. 3. The formation of RH was consistent during haloperidol decanoate treatment.

Administration, Oral↗
PubMed1992

Pericardiocentesis: a 20 patients study.

Emergency pericardiocentesis, guided by a two-dimensional echocardiography, was performed on twenty patients with symptomatic pericardial effusion of various types and causes. There were fourteen men and six women. The underlying causes were: primary lung cancer (6 cases), metastatic cardiac tumors (3 cases), tuberculosis (4 cases), complicated interventional procedures with cardiac chamber or vessel perforations (2 cases), dissecting aortic aneurysm (1 case), systemic lupus erythematous (1 case), idiopathic pericarditis (1 case), bacterial pericarditis (1 case), and myxedema heart disease (1 case). Seventeen cases were performed through the left xipho-sternal approach and 3 cases through the apical approach. None of the patients died as a result of these procedures. A two-dimensional echocardiogram is useful in diagnosing cardiac tamponade as well as in guiding pericardiocentesis, and obtaines highly positive results (20/20). The positive rate of pericardial fluid cytology for malignant cells was 89% (8/9), however, pericardial fluid cultures or direct smear for tuberculosis were negative (0/4). In cancer patients, the mean survival time following pericardiocentesis was 4.2 months (range, 1-7.8 months). We concluded that neoplastic involvement of the pericardium is the most frequent cause of symptomatic pericardial effusion. Pericardiocentesis assisted by a two-dimensional echocardiogram is safe and easy. In addition, pericarditis caused by TB is still significant and must be considered in every case in our nation.

Adult↗
PubMed1990

Plasma catecholamine metabolites in schizophrenics: evidence for the two-subtype concept.

Plasma homovanillic acid (pHVA) and plasma methoxyhydroxyphenyl glycol (pMHPG), as well as plasma haloperidol, were measured in 33 schizophrenic patients before and during 6 weeks of haloperidol treatment. Good responders had higher baseline pHVA values compared with poor responders (17.4 +/- 8.8 ng/ml, n = 22 versus 11.4 +/- 5.0 ng/ml, n = 11, p less than 0.05). A higher than 15 ng/ml pretreatment pHVA level was associated with a more consistent clinical response to the subsequent treatment. Differential pHVA changes during treatment were also found between good and poor responders. Within the good responder group, a significant decline in pHVA over time was found. By contrast, pHVA showed a transient increase in the poor responder group. Plasma MHPG changes showed a similar pattern during treatment in good responders, although no significant differences in baseline values were found between the good (n = 13) and poor (n = 9) responders, and pMHPG showed no change during treatment in poor responders. Significant correlations between baseline pHVA and pMHPG values were found in 22 patients. Good responders and poor responders did not differ significantly in terms of age, duration of illness, severity of presenting symptoms, haloperidol dose, or plasma drug concentration. Two hypothetical subtypes of schizophrenia and both dopamine and norepinephrine systems involved in schizophrenic psychopathology are proposed.

Adult↗
PubMed1990

Aortic and pulmonary input impedance in patients with cor pulmonale.

The hydraulic load of the right and left ventricles and the clinical effects of nifedipine were evaluated in 8 normal subjects (mean age: 55 years) and 8 patients with cor pulmonale secondary to chronic obstructive lung disease (mean age: 57 years). It was found that there were differences in the right ventricular resistance (174.62 +/- 25.96 vs 468.57 +/- 178.81 dyne/sec/cm-5), first zero crossing frequency (3.62 +/- 0.34 vs 6.07 +/- 3.56 Hz), steady power (218.95 +/- 32.25 vs 359.44 +/- 37.46 mW) and total power of right ventricle (275.81 +/- 36.18 vs 440.46 +/- 85.16 mW) between the normal and cor pulmonale patients, respectively. However, no significant changes in characteristic impedance, pulsatile power or aortic impedance were observed in the right pulmonary artery. After administration of nifedipine to patients with cor pulmonale, there were significant changes in resistance (468.57 +/- 178.81 vs 256.36 +/- 178.56 dyne/sec/cm-5), steady power (359.44 +/- 37.46 vs 225.51 +/- 114.64) and total power (440.46 +/- 85.16 vs. 289.27 +/- 50.85) of the pulmonary artery, respectively. Otherwise there were no significant changes in aortic input impedance or characteristic impedance of right pulmonary artery and pulsatile power. In conclusion, we found that: 1) the hydraulic vascular load in the right ventricle was higher in patients with cor pulmonale, 2) characteristic impedance that was not increased in cor pulmonale patients may be due to a dilated pulmonary artery, 3) there was no impedance mismatch between left ventricle and systemic arterial system in patients with cor pulmonale, and 4) by reducing the pulmonary vascular resistance through nifedipine administration, the total external right ventricular power might be reduced, without affecting the proximal pulmonary arterial compliance.

Aorta↗
PubMed1990

I-131-orthoiodohippurate renal function test in detection of renal artery occlusion in aortic dissection.

By use of I-131-orthoiodohippurate (I-131-OIH) comprehensive renal function test (CRFT), we studied 4 patients with aortic dissection and various degrees of renal artery obstruction and 39 patients without aortic dissection. Of the 39 patients, 3 had significant renal artery stenosis (RAS group) and 36 had normal renal arteriogram and renal function test (control group). Three of the 4 patients with aortic dissection had complicated renal artery occlusion (RAO group), one had independent RAS. The results indicate that: (1) In the RAO group, the difference in peak time (DPT) between the affected and contralateral kidneys was above 4 minutes: whereas that of the control group was 0-2 minutes (0.5 +/- 0.6 min). (2) In the RAO group, the percent difference of split effective renal plasma flow (%DSERPF) between the 2 kidneys were 29.6% and above or near 80% in patients with incomplete and complete RAO respectively; whereas that of the control group was below 22% (mean = 7.7 +/- 5.7%). In the RAS group, moreover, DPT was 0-2 minutes; and %DSERPF were above and below 22% in 1 case with marked (75% stenosis) and 2 with mild RAS (50-60% stenosis) respectively. The renogram curves were also evaluated. It was found that (1) In the RAO group, 2 cases with complete RAO showed flat shape in the affected kidney (similar to the background surve). The case with incomplete RAO showed markedly delayed rounding peak in phase 2 and slow descent in phase 3. The case with independent RAS showed only impaired phase 3 with saw-tooth waves and less steep slope. (2) In the RAS group, the 2 cases with mild RAS showed normal in one and slightly delayed peak with less steep descent in phase 3 in the other. The case with marked RAS showed reduced and delayed peak in phase 2, and less steep descent in phase 3 with saw-tooth waves and "cross-over" of the two kidney curves. It is concluded that use of I-131-OIH CRFT to evaluate DPT, %DSERPF and the renogram curve may help distinguish amongst RAO (with aortic dissection), RAS and the normal individual in most cases.

Adult↗
PubMed1989

Pharmacodynamics and pharmacokinetics of haloperidol and reduced haloperidol in schizophrenic patients.

Twelve male chronic schizophrenic inpatients, neuroleptic-free for at least 4 weeks, were given an oral test dose of 10 mg haloperidol (HAL) and reduced HAL (RHAL) in a random order, with a 2-week interval. Two weeks after the last test dose, the patients were given HAL, 5 mg orally twice daily for 7 days. Blood samples were drawn at baseline and between 0.5 and 24 hr after the test doses, and during HAL treatment as well. Plasma drug concentrations and homovanillic acid (HVA) levels were measured with high-performance liquid chromatography using electrochemical detection. HAL, but not RHAL, produced increments in plasma HVA (pHVA) levels at 24 hr after a test dose. pHVA levels remained higher than baseline during HAL treatment. Detectable interconversion between HAL and RHAL was observed in eight patients. The capacity of the reductive drug-metabolizing enzyme system, however, was greater than that of the oxidative processes. The plasma RHAL:HAL ratios on days 6 and 7 were higher than and positively correlated with those at Tmax after a single dose of HAL and were negatively correlated with the HAL:RHAL ratios at Tmax after a single dose of RHAL. Thus, both reductive and oxidative drug-metabolizing systems probably contribute to individual differences in plasma RHAL:HAL ratios in HAL-treated schizophrenic patients.

Adult↗
PubMed1989

Plasma homovanillic acid in schizophrenics: supportive evidence for the two-subtype hypothesis.

Plasma levels of homovanillic acid (pHVA), a major metabolite of dopamine (DA), were measured in a group of 51 schizophrenic inpatients before and during 6 weeks of neuroleptic treatment. Steady-state plasma drug concentrations were monitored in parallel with pHVA. Good responders (n = 22) had higher pretreatment pHVA levels as compared to poor responders (n = 22). Differential pHVA changes during neuroleptic treatment were also found between each group. The two groups did not differ significantly in terms of age, duration of illness, severity of presenting symptoms, neuroleptic, dose, or plasma drug concentration. Two hypothetical subtypes in the group of schizophrenics were proposed.

Adult↗
PubMed1988

Dose-response curves of homovanillic acid in pre-frontal cortex and caudate following antipsychotic drugs: relation to clinical potencies.

Dose-response curves for the elevation of homovanillic acid (HVA) levels, determined by high performance liquid chromatography using electrochemical detection, in the pre-frontal cortex and caudate of rats after acute treatment with 12 antipsychotic drugs are presented. The order of potency in both brain regions was: haloperidol greater than or equal to fluphenazine greater than loxapine greater than trifluoperazine greater than thiothixene greater than molindone greater than clopenthixol greater than chlorpromazine greater than metoclopramide greater than thioridazine greater than clozapine greater than sulpiride. This ranking is roughly correlated with that based on clinical potencies. The relative elevation of the content of HVA was weaker in the pre-frontal cortex than in the caudate for all drugs tested, except clozapine at a high dose.

Animals↗