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Biomedical subjects

W C Huang

Publications and source records attributed to W C Huang.

At least 55 records · Page 3Linked to original sources
PubMed1997

Glyceryl nonivamide, a nonpungent analogue of capsaicin, enhances substance P release and renal function in rats.

Effects of glyceryl nonivamide (GLNVA), a nonpungent analogue of capsaicin, on spinal substance P release, blood pressure and renal function were investigated in rats. GLNVA was administered intrathecally or intracerebroventricularly, and renal clearance function was measured. The addition of GLNVA at concentrations of 2, 20 and 200 mumol/l during in vivo spinal superfusion resulted in concentration-dependent increases in the release of substance P. Capsaicin pretreatment (50 mg/kg/day, s.c. for 2 weeks) blunted the GLNVA-induced substance P release, suggesting a stimulation of GLNVA on the spinal terminals of capsaicin-sensitive primary afferent nerves to release substance P. Intracerebroventricular administration of GLNVA at concentrations of 20, 40 and 80 nmol/l evoked a concentration-dependent depressor response. Despite the hypotensive effect, GLNVA caused significant increases in glomerular filtration rate, urine flow, absolute and fractional excretion of sodium and potassium, osmolar clearance and free water reabsorption rate. These data suggest that central administration of GLNVA stimulates spinal substance P release, reduces blood pressure but enhances renal excretion of water and electrolytes due to an increased filtered load and a decreased tubular reabsorption.

Absorption↗
PubMed1997

Visual field defects in patients with pituitary adenomas.

BACKGROUND: The most common objective manifestations of pituitary adenoma are visual, including impairment of a visual field and loss of acuity. The characteristic visual field defect caused by pituitary adenomas with suprasellar extension is bitemporal hemianopsia. The present study was undertaken to determine the relationship between a visual field defect and the chiasma compression caused by pituitary adenomas. METHODS: Between January 1994 and December 1996 within the Department of Neurosurgery at the Neurological Institute of Veterans General Hospital-Taipei, 70 patients with pituitary adenoma were selected. Their medical records and radiological films were reviewed. The qualified visual field scores were compared with the chiasma compression levels measured from computed tomography, sagittal and coronal magnetic resonance (MR) imaging. The relationships of pathological diagnosis as well as history of prior operations with visual field defect score were also evaluated. RESULTS: patients with a pathological diagnosis of a non-functional pituitary adenoma or with a history of prior operation for the pituitary adenoma had the more severe visual field defect. The chiasma compression level, no matter measured from computed tomography, sagittal MR or coronal MR imaging, was correlated significantly with the visual field defect. The correlation coefficient was 0.764 from computed tomography, 0.688 from sagittal MR imaging, and 0.717 from coronal MR imaging. The visual field defect was present mostly when the chiasma compression exceeded a certain level when measured from computed tomography, sagittal MR and coronal MR imaging. On the other hand, variation in chiasma type had little effect on the appearance and degree of a visual field defect. CONCLUSIONS: There was a linear correlation between a visual field defect and the chiasma compression no matter whether measured from computed tomography or from MR imaging. The visual field defect occurred mostly when the chiasma compression exceeded a certain level. A more severe visual field defect appeared in patients with nonfunctional pituitary adenoma or those with a prior operation history for the pituitary adenoma.

Adenoma↗
PubMed1996

Calcium mobilization from the intracellular mitochondrial and nonmitochondrial stores of the rat cerebellum.

Two major intracellular Ca2+ stores, the mitochondrial and nonmitochondrial (microsomes) fractions isolated from rat cerebellum exhibited a Ca2+ concentration and ATP-dependent Ca2+ accumulation. The maximal Ca2+ accumulation in mitochondria was higher than in microsomes, but the affinity of the mitochondria for Ca2+ was lower. In this study, Ca2+ accumulation within the mitochondria was energized by ATP hydrolysis. Thus, the protonophore, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, and the F1F0 ATP synthase inhibitor, oligomycin, blocked Ca2+ accumulation and induced the discharge of the entrapped Ca2+ in the mitochondria, whereas the metabolic inhibitor, rotenone, affected neither the Ca2+ accumulation nor discharge. On the other hand, the uniporter inhibitor, ruthenium red, blocked the mitochondrial accumulation of Ca2+, but did not cause the discharge of preloaded Ca2+. In addition, arachidonic acid (AA), sphingosylphosphorylcholine (SPC) and sphingosine (SPH) elicited the dose-dependent release of Ca2+ from microsomal stores. Although the magnitudes of the Ca2+ release induced by AA, SPC or SPH were all dependent on the presence of extravesicular Ca2+ at concentrations ranging from 0.01 to 0.1 microM Ca2+, only the AA- and SPC-evoked Ca2+ releases were insensitive to temperature. The mitochondria were more sensitive than the microsomes to the AA induced release of accumulated Ca2+. Our results indicate the existence of multiple intracellular Ca2+ stores in nerve cells which can be released by various Ca2+ mediators.

Animals↗
PubMed1996

A simple, sensitive, non-stimulated photon counting system for detection of superoxide anion in whole blood.

A simple, sensitive, non-stimulated assay was developed to measure the superoxide anion concentration in whole blood, using an ultra-sensitive chemiluminescence (CL) analyzer and lucigenin amplification. The assay system can be performed without leukocyte isolation or stimulant administration. The blood CL levels of healthy males (362.8 +/- 337.7 counts /10 sec) were not different from those of females (335 +/- 308.7 counts/10 sec) (p=0.64), whereas the CL levels in whole blood in patients with acute pancreatitis (2522 +/- 2014 counts/10 sec) were significantly higher than those of healthy controls (p<0.001). This assay system may be valuable in the future for quantitative measurement of reactive oxygen species in various disorders.

Acridines↗
PubMed1996

Conformation of Vespa basalis mastoparan-B in trifluoroethanol-containing aqueous solution.

Mastoparan-B, a tetradecapeptide isolated from the venom of the hornet Vespa basalis, belongs to the mastoparan analogs of vespid venom with the lysine residues common for all mastoparan family toxins at positions 4, 11 and 12. Here we use 1H-NMR spectroscopy and hybrid distance geometry-simulated annealing calculation to investigate its three-dimensional structure in trifluoroethanol-containing aqueous solution. The calculated structure shows that residues 3-14 adopt an amphiphilic alpha-helical structure in which the residues with hydrophilic side chains (i.e. Lys-4, Ser-5, Ser-8, Lys-11, Lys-12) are located on one side and the residues with hydrophobic side chains (i.e. Leu-3, Ile-6, Trp-9, Ala-10, Val-13, Leu-14) located on the other side of the molecule. The overall structural features a very similar to the conformation of mastoparan-X reconstituted in vesicle [Wakamatsu et al. (1992) Biochemistry 31, 5654-5660] in spite of the substitutions made for eight residues with distinctly different hydrophobicity. These substitutions lead to a larger hydrophobic moment for the alpha-helical segment and further mobilized N-terminal. This study will help reveal the conformational significance of mastoparan toxins with respect to their potency and activity in G protein regulation.

Amino Acid Sequence↗
PubMed1996

A reexamination of "sociological and economic theories of suicide: a comparison of the U.S.A. and Taiwan".

This paper is an update and reexamination of Yang et al. [Yang B., Lester D. and Yang C. Soc. Sci. Med. 34, 333, 1992]. Time-series analyses were carried out to explore the importance of sociological and economic determinants of suicide rates in the U.S. and in Taiwan for 1952-1992. Labor market related variables (unemployment and female labor force participation) were found to play similar roles in multiple regressions for both nations, while general economic and social conditions (GNP per capita and divorce) played a role only in the U.S.A comparison of standardized coefficients revealed that pure economic variables exerted greater influence over national suicide rates than sociological variables.

Cross-Cultural Comparison↗
PubMed1996

Testosterone enhances whereas estrogen inhibits calcium oxalate stone formation in ethylene glycol treated rats.

PURPOSE: The present study was conducted to extend our earlier study on the role of testosterone in the pathogenesis of urolithiasis and to further investigate the influence of sex hormone on the pathogenesis of calcium oxalate stone. MATERIALS AND METHODS: Adult Sprague-Dawley rats were divided into 9 groups, each containing 10 rats. Two groups of rats were left untreated and served as male and female controls. Another 7 groups of rats were fed a 0.5% ethylene glycol (EG) lithogenic diet for 4 weeks. Among them, 2 groups were male and female rats, 2 groups were castrated, 2 groups were castrated and then were subcutaneously implanted with testosterone, and 1 group of intact female rats was also subcutaneously implanted with testosterone. The stone and crystal deposits were examined by infrared spectrometer and polarizing and scanning electron microscope, respectively. Serum testosterone, creatinine and electrolytes and the renal excretion of, oxalate, citrate and creatinine were determined. RESULTS: Subcutaneous implantation of exogenous testosterone restored calcium oxalate stone formation in castrated, EG-treated male rats (80%) and enhanced urolithiasis in castrated female rats receiving EG (40%). However, the testosterone effect was less striking in intact female rats fed EG (10%). CONCLUSIONS: These data suggest that testosterone can promote and estrogen may inhibit calcium oxalate stone formation in EG-treated rats.

Animals↗
PubMed1996

A survey of Gnathostoma larvae in fresh water fish in the valley of the Yangtze River and morphological characteristics of the recovered larvae.

Investigations of the prevalence of larval gnathostomes in fresh water fishes were carried out at the southeastern Yangtze Valley, People's Republic of China, in the periods of October 1989 and November 1990. Fishes were collected from Shanghai, Chenchiang, Nanching, Chiuchiang and Nanchang districts in 1989. Additional sampling in Shanghai district was done at Kunshan, Tien-shanfu, Chingpu and Nanhui. Species of fishes collected were Channa argus (110), Siniperca chuatsi (24) and Silurus asotus (2). Muscle tissue of the fishes was dissected into small pieces, sliced and then examined under a dissecting microscope. The viscera were pooled by species in groups of 4 or 5 individuals, homogenized, and were then digested overnight in artificial gastric-juice at 37 degrees C. Four encysted larvae were recovered from the muscle tissue of four C. argus. Thirty-four larvae were obtained from digestion of viscera. A total of 38 larvae were recovered. Eighteen of 38 larvae were examined morphologically and they were able to be divided into three types by their body length; 5 early third-stage larvae (0.58-0.86 mm), 12 third-stage larvae (1.12-2.61 mm), and one advanced third-stage larva of 4.86 mm. Light and scanning electron microscopy revealed that the former two types had characteristics of Gnathostoma hispidum and the last one had those of G. spinigerum. In 1990, we investigated fish near Hongtze-hu and Tai-hu lakes. A total of 553 fishes belonging to 12 genera and 12 species were examined. Seventeen larvae were recovered from the viscera of G. argus and Monopterus albus. These larvae were identified as G. hispidum.

Animals↗
PubMed1994

The long-term stone recurrence rate and renal function change in unilateral nephrectomy urolithiasis patients.

We evaluated the stone recurrence rate and long-term renal function in 50 patients with a solitary kidney 60 to 84 months (mean 70.6) after unilateral nephrectomy for urinary tract stone disease. Followup evaluation included a detailed history, physical examination, blood and urine biochemistry studies, urinalysis, urine culture, excretory urography, ultrasonography of the kidney and 131iodine-ortho-iodohippurate renography. The overall stone recurrence rate in unilateral nephrectomy urolithiasis patients was 30% (15 of 50). The mean interval until stone recurrence was 31.1 months (range 6 to 74) and the mean episodes of recurrence were 2.1 times per patient (range 1 to 5). Function of the remnant kidney in most patients was unchanged during followup. However, 2 of the 15 patients with recurrent stones had anuria during the acute attack of renal colic and, thus, required percutaneous nephrostomy urinary diversion, while 1 had proteinuria (3 gm. per day) and progressive renal failure 47 months after nephrectomy. The metabolic stone patients seemed to experience recurrence more easily than metabolic stone patients seemed to experience recurrence more easily than infection stone patients (37% versus 13%) but no statistically significant difference was noted (p = 0.198).

Adult↗
PubMed1994

[Serum apolipoprotein abnormalities in patients with idiopathic nephrotic syndrome].

We measured serum lipid and apolipoprotein (apo) levels in 45 patients with normal renal function at different stages of idiopathic nephrotic syndrome (NS). Wide abnormalities of lipid metabolism were found. The characteristic disorder of serum apos in NS was a decrease in apoAI and AII and a significant increase in apoB, CII, and CIII. Consequently, the ratio of apoAI to apoB was significantly decreased. Some patients with NS in remission had normal serum lipid concentrations, but abnormalities of serum apos were still observed. It is suggested that the nephrotic patients may be at increasing risk for coronary heart disease (CHD), and that apos may be more sensitive predicators of CHD than lipids.

Adolescent↗
PubMed1994

The absence of influence of chronic hyperinsulinemia on the development of renovascular hypertension in rats.

Our previous studies have shown that sustained hyperinsulinemia increases blood pressure in rats. The precise mechanism is still unclear. The present study was conducted to assess if hyperinsulinemia could interact with angiotensin II and other pressor stimuli to increase blood pressure in renovascular hypertensive rats. Intact and uninephrectomized Sprague-Dawley rats with unilateral renal arterial constriction (2-kidney, 1 clip and 1-kidney, 1 clip Goldblatt rats) were administered insulin (3 mU/kg/min) for 6-12 weeks. The clipped rats without insulin infusion and normal rats served as controls. Changes in blood pressure were measured by tailcuff method without preheating. Results showed that either sustained infusion of insulin or renal arterial clipping alone in normal rats significantly increased the blood pressure. Superimposed infusion of insulin for 6-7 weeks into rats with unilateral renal artery constriction in either 2-kidney or 1-kidney model did not accelerate nor exacerbate the development of hypertension. There were no significant differences in body weight and plasma levels of glucose, triglycerides, sodium and potassium between 2-kidney, 1 clip Goldblatt hypertensive rats with and without insulin infusion. These data suggest that chronic hyperinsulinemia and angiotensin II do not act synergistically to increase the blood pressure in rats.

Animals↗
PubMed1993

[Diagnosis and treatment of cysticercosis of cerebral ventricles].

31 patients with cysticercosis of cerebral ventricles verified by operation or pathological investigation were reported. All patients were between 7 and 64 years of age and 14 were females. All had a single cyst. Since 29 patients (94%) were without a history of intestinal taeniasis, it was proposed that most patients of cysticercosis of cerebral ventricles were caused by hetero-infection and the entrance of Cysticercus into brain ventricle was through choroid plexus along the cerebrospinal fluid. This is probably the reason why it occurs mostly in the 4th ventricle. The clinical manifestation of cysticercosis of cerebral ventricles were paroxysmal headache and vomiting caused by increased intracranial pressure. Ventriculography and CT scanning have considerable diagnostic value. Removal of Cysticercus by surgical operation is successful (Figs. 1-8).

Adolescent↗
PubMed1992

Enhanced renal response to intracerebroventricular angiotensins II and III in spontaneously hypertensive rats.

The acute effects of intracerebroventricular (i.c.v.) administration of angiotensin III (ANG III) on blood pressure (BP) and renal function were investigated in spontaneously hypertensive rats (SHR, n = 31) and Wistar-Kyoto (WKY) normotensive rats (n = 6). ANG II was also administered to the same rats for comparison of its renal effect. BP and renal clearance responses were measured before and during ANG injections. The results showed that i.c.v. injections of 1, 5 and 50 pmol of ANG III did not significantly alter BP in SHR, but a high dose of ANG III (50 pmol) caused a vasopressor effect (7 +/- 4 mmHg) in WKY rats. There were significant increases in renal plasma flow (RPF), glomerular filtration rate (GFR), urine flow, absolute and fractional excretions of sodium and potassium, osmolar clearance and free water reabsorption rate following i.c.v. administration of ANG III in both SHR and WKY rats. However, the enhancement in renal responsiveness to ANG III was greater in SHR than in the WKY group. At 5 pmol of ANG III, the peak increases in GFR (96 +/- 23%), diuresis (316 +/- 102%) and natriuresis (712 +/- 281%) in SHR were significantly greater than those in WKY rats (40 +/- 13%, 152 +/- 89%, 229 +/- 130%, resp.). The renal effect of central ANG III was blocked by i.c.v. ANG III antagonist, [Ile7]-ANG III, but was enhanced by bestatin, an ANG III metabolic enzyme inhibitor. I.c.v. administration of ANG II at 50 pmol increased BP in both SHR and WKY rats (14 +/- 3 and 10 +/- 3 mmHg, resp.). Greater diuretic and natriuretic responses to ANG II were also noted in SHR than in WKY rats. These results indicate that central ANG III is as active as ANG II in modulating renal function. Furthermore, the enhanced renal response to i.c.v. ANGs II and III in SHR suggests a hyperactive central RAS implicated in BP and body fluid regulation in this genetic hypertensive strain.

Angiotensin II↗
PubMed1992

Determinant role of testosterone in the pathogenesis of urolithiasis in rats.

By using an ethylene glycol-induced urolithiasis model, we assessed the role of testosterone in the pathogenesis of urolithiasis. The intact and castrated male and female rats were fed with 0.5% ethylene glycol in drinking water for four weeks. The renal excretions of oxalate, citrate and other electrolytes were measured, and the stone and crystal deposit were examined microscopically. The results showed that drinking a loading of 0.5% ethylene glycol for four weeks produced hyperoxaluria in all rats, but the intact male rats excreted more urinary oxalate than any other groups of rats. The ethylene glycol-fed rats exhibited hypocitraturia except the castrated male rats. However, urolithiasis occurred in intact male but not female rats. Castration in male rats fed with ethylene glycol dramatically decreased the incidence of renal stone from 71.4% (5/7) to 14.3% (1/7). On the other hand, there was still no renal stone formed in the oophorectomized female rats which received ethylene glycol treatment. These data indicate that serum testosterone level plays a determinant role in urolithiasis formation.

Animals↗
PubMed1992

Uninephrectomy enhances urolithiasis in ethylene glycol treated rats.

Uninephrectomy (uNX) usually induces compensatory hyperfunction of the remaining kidney in an attempt to preserve the homeostasis of body fluid composition. The present study used uninephrectomized Sprague-Dawley rats on a lithogenic diet (0.5% ethylene glycol, EG) to evaluate the influence on urinary stone formation and calcium oxalate crystal deposition of compensatory excretion of lithogenic substances in the remnant kidney. The results showed that there were no urinary stones or calcium oxalate crystal deposits in the intact or uNX rats fed a normal diet. In the EG feeding groups, the incidence of massive (grade 3) crystal deposits was significantly higher in the uNX rats (87.5%) than that in the intact rats (37.5%; P less than 0.05). The incidence of urinary stone formation was also higher in the uNX rats as compared to that of the intact rats, although the difference did not achieve statistical significance. The serum magnesium, phosphorus and creatinine increased significantly, whereas creatinine clearance (CCr), 24-hour urinary excretions of citrate, sodium, potassium and chloride decreased significantly in the uNX rats fed EG. These data indicate that uninephrectomy increases the vulnerability of the contralateral remnant kidney to urolithiasis and crystal deposition when the lithogenic risk factors are present. Furthermore, once the remnant kidney forms urolithiasis or massive calcium oxalate crystal deposits, the renal function is severely compromised.

Animals↗
PubMed1992

Angiotensin-converting enzyme inhibition causes deterioration in renal function in one-kidney Goldblatt hypertensive rats with and without renal arterial stenosis.

1. The renal and hypotensive effects of a new angiotensin-converting enzyme (ACE) inhibitor, cilazapril, were evaluated in 18 one-kidney, one-clip Goldblatt hypertensive rats (1K1C), 10 one-kidney normotensive rats (1K) and eight 1K1C rats with acute unclipping (1KU). Cilazapril was infused intravenously (25 micrograms/kg per min) into anaesthetized rats, and the arterial blood pressure (BP) and renal clearance of rats were measured. 2. In 1K rats, cilazapril reduced BP from 123 +/- 4 to 117 +/- 4 mmHg (P < 0.05), and produced diuresis, natriuresis and kaliuresis without significantly changing glomerular filtration rate (GFR). 3. In 1K1C rats, cilazapril significantly reduced BP (from 157 +/- 5 to 143 +/- 6 mmHg; P < 0.05), GFR (14.4 +/- 6.7%), urine flow (27.1 +/- 8.5%) and sodium excretion (39.4 +/- 7.4%). Mechanically graded reductions of renal arterial pressure alone also produced parallel decreases in GFR and renal excretory function. 4. In 1KU rats, removal of the renal arterial clip significantly decreased BP and increased renal function. Subsequent infusion of cilazapril further reduced BP and urinary excretions of sodium and water but did not significantly change GFR. 5. These results suggest that the renal function of the 1K1C hypertensive model is pressure-dependent, and that ACE inhibitor exerts a mild antihypertensive effect but causes a pressure associated reduction in renal function. Furthermore, the detrimental effect of ACE inhibitor on the residual kidney persists after acute surgical correction of the stenosis.

Animals↗
PubMed1992

[Sleep quality and nocturnal hypoxemia in patients with chronic obstructive pulmonary disease].

To evaluate the incidence of sleep apnea syndrome (SAS), oxygen desaturation during sleep and sleep quality in patients with chronic obstructive pulmonary disease (COPD), 30 COPD patients and 20 healthy snorers (without SAS) were studied. Each subject received a pulmonary function test (PFT) (simple spirometry), arterial blood gas determination and an overnight sleep study. COPD patients were divided into two groups: those with SAS (group I) and those without (group II). Group II patients were further subdivided into: group IIa [delta SaO2 < 15% (delta SaO2 = baseline SaO2-lowest SaO2) and group IIb (delta SaO2 > or = 15%); group IIc (baseline SaO2 > 90%) and group IId (baseline SaO2 < or = 90%). Our results showed that only six of 30 (20%) COPD patients had an associated SAS. Among group II patients, the lowest SaO2 and delta SaO2 were correlated with baseline SaO2, PaO2 and PaCO2 but were not correlated with age, % of ideal body weight, FVC, FEVl, FEVl/FVC. Group IIb patients (n = 10) had a lower SaO2 during sleep, a lower baseline PaO2, and a lower hematocrit level than group IIa patients (n = 14). Group IId patients (n = 9) had a lower PaO2 and a higher delta SaO2 during sleep than group IIc patients (n = 15). However, there were no significant differences in age, percent of ideal body weight (IBW), FVC, FEVl or FEVl/FVC values between groups IIa and IIb, or between groups IIc and IId. Group II patients had a lower percentage of sleep efficiency, higher arousal and movement indices and a longer period of stage 1 sleep, compared to the control group. In conclusion, the incidence of COPD patients with SAS is 20%. Age, percentage of IBW, FEVl, and FEVl/FVC values are not reliable predictors of the risk of nocturnal hypoxemia among COPD patients. However, a possible correlation between baseline SaO2, PaO2 and PaCO2 values and the incidence of nocturnal hypoxemia exists. Finally, COPD patients experienced a poorer quality of sleep in comparison with the control group.

Aged↗