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Biomedical subjects

T L Hwang

Publications and source records attributed to T L Hwang.

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

Prognostic study of gastric cancer without serosal invasion: reevaluation of the definition of early gastric cancer.

BACKGROUND: Early gastric cancer, a term defined by Japanese researchers in the 1960s, is equivalent to pT1 tumor stage regardless of nodal status. Recently, there were suggestions to exclude node-positive pT1 gastric cancer from this entity and to consider node-negative pT2 gastric cancer as early gastric cancer. STUDY DESIGN: A survival analysis was conducted of 294 patients who underwent resection for gastric cancers confined within the gastric wall (pT1, n = 164; pT2, n = 130) between 1986 and 1992. RESULTS: The cumulative 5-year survival rate was 93.5% for pT1 patients and 67.9% for pT2 patients, with an overall survival of 82.5%. There was a significant difference in the 5-year survival rate between node-positive and node-negative pT1 patients (72.8% versus 95.6%; p = 0.0095). The 5-year survival rate of node-negative pT2 patients (80.4%) was significantly worse than that of node-negative pT1 patients (p = 0.011) but was not significantly better than that of node-positive pT1 patients (p = 0.4). If excellent prognosis is a prerequisite for the definition of early gastric cancer, then node-positive pT1 cancer and node-negative pT2 cancer should not be considered early gastric cancer. CONCLUSIONS: In the 1990s, now that new imaging techniques such as endoscopic ultrasonography has been introduced, the preoperative staging of gastric cancer can be made more accurately than in the 1960s, when the term "early gastric cancer" was defined. Because the prognosis of early gastric cancers, if subcategorized by nodal status, is not homogeneously excellent, a reevaluation of the definition of early gastric cancer may be necessary.

Adolescent↗
PubMed1997

Role of hepatic resection in surgery for bilateral intrahepatic stones.

BACKGROUND: Hepatic resection is the treatment of choice for unilateral intrahepatic stones. The availability of the flexible choledochoscope has greatly changed the management of intrahepatic stones. Little has been reported regarding hepatic resection for bilateral intrahepatic stones. METHODS: Fifty-nine (15.1 per cent) of 392 patients with bilateral intrahepatic stones underwent hepatic resection. The indications and results were reported. Surgical outcome and long-term follow-up were analysed, and results were compared with those in patients not undergoing hepatectomy. RESULTS: Fifty-nine patients underwent hepatic resection because of destruction of the left liver by repeated infection (n = 40), multiple cholangitic liver abscesses (n = 18) or associated intrahepatic cholangiocarcinoma (n = 1). The hospital mortality rate was 1.7 per cent. The majority of complications were wound infection (9 per cent), haematobilia (5 per cent) and biliary fistula (3 per cent). The incidence of residual stones after surgery was 60 per cent. One year after postoperative choledochoscopic stone extraction, the rate of complete stone clearance was 84 per cent. In patients who did not have hepatectomy the respective rates were 90.1 and 52.9 per cent. The recurrence rate for stones in the hepatectomy and no-hepatectomy groups was 12 and 33.0 per cent respectively. CONCLUSIONS: Compared with patients not undergoing hepatectomy, those having hepatic resection had similar operative risks, fewer residual stones and a low incidence of recurrent stones (P < 0.05).

Adult↗
PubMed1996

Predilection of brain metastasis in gray and white matter junction and vascular border zones.

BACKGROUND: The purpose of this study was to asses the importance of the vascular border zone and the gray and white matter junction on the distribution of brain metastases. METHODS: We reviewed the medical records, computed tomography (CT) of magnetic resonance imaging (MRI) of 105 patients with secondary brain tumors. The metastatic lesions noted on CT scans of MRI ere matched with a predetermined standard sheet containing axial images with shading on the border zones. To be included in the border zones, the center on more than 50% of the lesion had to be situated within these zones. RESULTS: Among 100 evaluable patients, there were 302 metastatic brain lesions. Of the 302 lesions, 210 lesions were 2 cm or smaller in greatest dimension and located in the cerebral and cerebellar hemispheres. The major vascular border zones were the site of predilection for 103 lesions (62%) although the border zones constitute only 29% of the area. Gray and white matter junction was the preferred site for 135 lesions (64%). CONCLUSION: The results demonstrated that brain metastasis occurs in the vascular border zone regions and the gray and white matter junction more frequently than previously recognized, and also supported the notion that metastatic emboli tend to lodge in an area of sudden reduction of vascular caliber (gray/white matter junction) and in the area most distal vascular field (border zone).

Adult↗
PubMed1996

The effect of gabexate mesilate on pancreatic and hepatic microcirculation in acute experimental pancreatitis in rats.

Microcirculatory derangements are important early features in many organs during the process of acute pancreatitis. However, dynamic evaluation of these factors has been difficult. Antiprotease has long been used for the treatment of acute pancreatitis, although its effects and mechanism have not been fully elucidated. The involvement of proteases and microcirculatory derangement early in the course of acute pancreatitis are the main concern of this study. A severe acute pancreatitis model in male Sprague-Dawley rats (225-275 g) was established by adding caerulein (15 microg/kg/ hr) in intravenous infusion fluid and intraductal injection of 0.1 ml glycodeoxycholic acid (5 mM). Gabexate mesilate [GM; ethyl-4-(6-guanidinohexanoyloxy)benzoate methanesulfonate], a synthetic antiprotease, was infused intravenously in doses of 0.01, 0.1, 1, and 10 mg as a therapeutic intervention in this model. Pathology hematocrit, serum amylase level, and glutamic-oxaloacetic transaminase (GOT) levels were used to confirm the severity of disease and effect of therapy. In vivo microscopic technique was used as a investigating tool in this study of microcirculatory derangement in pancreas and liver, 8 hr after induction of acute pancreatitis. GM can significantly improve pathologic criteria and changes of serum amylase levels in the range of 1-10 mg/kg/hr. The severity of changes of hematocrit and GOT was significantly lessened with GM in the range of 0.1-10 mg/kg/hr. This agent also could improve the microcirculatory environment in pancreas and liver after induction of acute pancreatitis according to the parameters, such as flow velocity and rolling leukocyte phenomenon, in the range of 1-10 mg/kg/hr. According to our observation, severity of hyperpermeability had not changed with the treatment of GM. These results indicated the beneficial effects of GM on pancreatic and hepatic microcirculation early in the course of acute pancreatitis. The beneficial effects were noted in serum parameters and hematocrit. The importance of protease activation and remote organ dysfunction is emphasized in the course of acute pancreatitis from this study.

Acute Disease↗
PubMed1996

Surgical treatment of hepatolithiasis: long-term results.

BACKGROUND: Hepatolithiasis is a common disease in East Asia and is prevalent in Taiwan. Surgical and nonsurgical procedures for management of hepatolithiasis have been discussed, but long-term follow-up results of surgical treatment of hepatolithiasis are rarely reported. METHODS: We conducted a retrospective study of case records of patients with hepatolithiasis who underwent surgical or nonsurgical percutaneous transhepatic cholangioscopy treatment. Of 614 patients with hepatolithiasis seen between January 1984 and December 1988, 427 underwent follow-up after surgical (380) or percutaneous transhepatic cholangioscopy (47) treatment for 4 to 10 years and constituted the basis of this study. RESULTS: Long-term results of 427 patients with hepatolithiasis after surgical and nonsurgical treatment within 4 to 10 years of follow-up were recurrent stone rate 29.6% (105 of 355), repeated operation 18.7% (80 of 427), secondary biliary cirrhosis 6.8% (29 of 427), late development of cholangiocarcinoma 2.8% (12 of 427), and mortality rate 10.3% (44 of 427). The patients with hepatectomy had a better quality of life (symptom-free) with a lower recurrent stone rate (9.5%), lower mortality rate (2.1%), and lower incidence of secondary biliary cirrhosis (2.1%) and cholangiocarcinoma (0%) than did the nonhepatectomy group (p < 0.01). The patients without residual stones after choledochoscopy had a better quality of life than did the residual stone group (p < 0.01). CONCLUSIONS: Long-term follow-up study of hepatolithiasis after surgical treatment revealed a high recurrent stone rate (29.6%) that required repeated surgery and a high mortality rate (10.3%) resulting from repeated cholangitis, secondary biliary cirrhosis, and late development of cholangiocarcinoma. Patients who received hepatectomy or without residual stones after choledochoscopy had a good prognosis and quality of life.

Adolescent↗
PubMed1996

Peritoneal nitric oxide is a marker of peritonitis in patients on continuous ambulatory peritoneal dialysis.

Nitric oxide plays an important role in mediating the inflammatory process. The aim of this study was to evaluate if nitric oxide production was increased during peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD), and the association with the prognosis. The study population comprised 21 patients with 22 episodes of peritonitis. Fifteen patients without peritonitis were controls. Nitrate was measured by HPLC and nitrite by the Griess method, to reflect nitric oxide production. Peritoneal dialysate effluent and plasma were collected from six patients during peritonitis and 1 week after treatment to study changes in dialysate:plasma ratio. In 15 patients, nitrite was measured during peritonitis and every 3 days for 2 weeks or until normalized for evolutional changes. The dialysate:plasma ratios of nitrate and nitrite during peritonitis were reduced 26% and 41.5%, respectively, after 1 week of treatment, indicating the peritoneal production of nitric oxide during peritonitis. In the evolutional study, a 5.1-fold increase of peak nitrite levels in bacterial peritonitis (n = 13) and a 2.5-fold increase in fungal peritonitis (n = 3) were observed compared to controls. Nitrite gradually declined to control levels (9.3 +/- 7.2 days) after effective antibiotic treatment, but took longer than to normalize leukocyte count in the peritoneal dialysate effluent (3.9 +/- 1.9 days). In four patients with refractory peritonitis (Candida infection in three, Acinetobacter infection in one), the nitrite levels remained elevated 2-fold despite treatment, and the catheters were removed. It is concluded that nitrite levels in peritoneal dialysate effluent may serve as a marker to assess treatment efficacy in CAPD patients with peritonitis.

Acinetobacter Infections↗
PubMed1996

Effect of serum from partially hepatectomized cirrhotic and noncirrhotic rats on liver regeneration with primary hepatocyte cultures.

The effects of serum from cirrhotic and noncirrhotic rats after 33% and 70% partial hepatectomy on the hepatocyte culture were studied. Liver cirrhosis was produced by weekly intragastric feeding with carbon tetrachloride (CCl4) for 12-16 weeks. The serum was prepared with blood withdrawn from the rats 2 and 48 h after partial hepatectomy or sham operation. The incorporation of [3H]thymidine in the hepatocyte culture after addition of rat serum (1.0 +/- 10(5) cells/ml) was assessed. We found that the mitogenic effect of the serum at 2 and 48 h after partial hepatectomy was not significant. In the 70% hepatectomy group, the serum from cirrhotic rats had a stronger stimulatory effect to induce hepatocytes in primary culture entering DNA synthesis than that from noncirrhotic rats; but the difference was not statistically significant. The mitogenic effect of the serum from noncirrhotic rats after 33% hepatectomy was significantly lower than that from cirrhotic rats after 33% hepatectomy (p < 0.05). In this series, the serum from the cirrhotic rats after 33% hepatectomy had the strongest mitogenic effect; the serum from the partially hepatectomized rats with cirrhotic and non-cirrhotic livers increased [3H]thymidine uptake into hepatocyte DNA significantly more than control serum or plasma.

Animals↗
PubMed1996

Brain SPECT with dipyridamole stress to evaluate cerebral blood flow reserve in carotid artery disease.

UNLABELLED: This is a preliminary study of SPECT brain scan using dipyridamole as a stress agent to assess cerebral blood flow reserve in six patients with severe carotid artery disease. METHODS: We performed SPECT scanning of the brain, with and without dipyridamole stress. Dipyridamole (0.57 mg/kg) was given intravenously 3 min before infusion of 99mTc-HMPAO. Patients were studied 30 min later using a rotating head gamma camera. The scans were analyzed qualitatively and semiquantitatively. An acetazolamide stress SPECT image was also obtained in two patients. RESULTS: All patients had at least 80% stenosis in one internal carotid artery, three of them also had contralateral carotid stenosis. The dipyridamole SPECT showed an increased region of hypoperfusion in the hemisphere ipsilateral to the severe carotid disease in four patients. That suggests poor perfusion reserve and the potential risk of regional ischemia. In four of six patients, side-to-side asymmetry increased from the baseline condition after injection of dipyridamole. The asymmetry index increased more after dipyridamole than after acetazolamide injection in two patients. CONCLUSION: This study suggests that dipyridamole stress SPECT is useful in assessing cerebral blood flow reserve. It demonstrates the region of poor vascular reserve in patients with severe carotid artery disease. Dipyridamole SPECT scans show more extensive hypoperfusion than acetazolamide in the two cases.

Acetazolamide↗
PubMed1996

Analysis of mechanical restitution and post-rest potentiation in isolated rat atrium.

Mechanical restitution and post-rest potentiation in isolated rat atria were studied in order to understand the intracellular Ca2+ handling during stimulation and interbeat interval. Various agents known to affect transmembrane Ca2+ inward current or Ca2+ accumulation of the sarcoplasmic reticulum were examined. The tissues were stimulated at 1 Hz and ectopic stimuli of different preceding intervals were driven by a programmable stimulator. The relationship between the force produced by the ectopic contraction and the duration of the preceding interval was plotted to construct mechanical restitution curves. Mechanical restitution curve was well fitted to two exponential processes, i.e., an early rapid phase followed by a slowly rising phase. It is suggested that the time constant in early phase (tau 1) of mechanical restitution curve is dependent on the reactivation of transmembrane Ca2+ inward currents as well as the translocation of Ca2+ within the sarcoplasmic reticulum. However, the time constant in late phase (tau 2) involves the rate of Ca2+ influx or efflux possibly via the Na+/Ca2+ exchange mechanism. The present studies suggest that in rat myocardium, verapamil enhances the buffering capacity of the sarcoplasmic reticulum inside the cell, while isoproterenol appears to short circuit the buffering barrier of the sarcoplasmic reticulum and enhance the flow of Ca2+ into the cytosol. Ryanodine, which accelerates the Ca2+ release from the sarcoplasmic reticulum, is believed to attenuate its buffering capacity. The present analytical methods to which the mechanical restitution and the post-rest potentiation are combined would represent a good model for the study of beat-to-beat intracellular Ca2+ handling in cardiac muscle.

Animals↗
PubMed1995

Liver regeneration following partial hepatectomy and stimulation by hepatic stimulatory substance in cirrhotic and non-cirrhotic rats.

The effects of hepatic stimulatory substance (HSS) on cirrhotic and non-cirrhotic rats were studied after 70% partial hepatectomy. Liver cirrhosis was produced by weekly intragastric infusion of chloroform for 12-16 weeks. The HSS was prepared by extraction from the livers of weanling mice. Rats in the experimental group were injected with 5 ml HSS after 70% partial hepatectomy, and those in the control group received normal saline. The results showed that the 3H-thymidine incorporation was higher in the HSS group 24 h after partial hepatectomy in both cirrhotic and non-cirrhotic rats, and persistently higher in the non-cirrhotic rats at 48 h. Total DNA was significantly higher in the HSS group of non-cirrhotic rats 24 and 48 h after partial hepatectomy. The restituted liver volume and weight was significantly higher in non-cirrhotic rats 48 h after partial hepatectomy, while there was no significant difference between the HSS and the control groups in the cirrhotic rats. The HSS induced significant effects on 3H-thymidine incorporation in the non-cirrhotic liver, resulting in increasing liver weight, volume and total DNA 48 h after partial hepatectomy. In cirrhotic rats, the 3H-thymidine incorporation was higher in the HSS group at 24 h after partial hepatectomy, though not showing any increase at 48 h, but the regeneration of liver weight, volume and total DNA at 48 h showed no difference between the HSS group and the control group.

Animals↗
PubMed1995

Changes in inositol 1,4,5-triphosphate binding in microsomal fractions from the rat liver during sepsis.

Inositol 1,4,5-triphosphate has been proposed as a second messenger for calcium mobilization. The addition of inositol 1,4,5-triphosphate at a low concentration has been shown to cause calcium release from intracellular microsomal stores in rat hepatocytes. The effects of sepsis on the inositol 1,4,5-triphosphate binding from microsomal fractions of rat liver were investigated. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham operated. Three microsomal fractions (rough, intermediate, and smooth I) were isolated from the rat liver. The study of inositol 1,4,5-triphosphate receptor binding was performed with tritium-labeled inositol 1,4,5-triphosphate. Our results showed that the Bmax of inositol 1,4,5-triphosphate binding in early septic, late septic, and control groups was 14.9 +/- .9 fmol/mg, 9.8 +/- 1.0 fmol/mg, and 17.2 +/- 1.3 fmol/mg, respectively. The binding activity was unaffected during early sepsis but was significantly depressed by 40-50% (p < .05, vs. control) during late sepsis (18 h after CLP) in all three subfractions of endoplasmic reticulum. Because the inositol 1,4,5-triphosphate binding plays an important role in the regulation of intra-cellular calcium homeostasis in hepatocytes, an impairment of the calcium release due to depressed inositol 1,4,5-triphosphate binding in the endoplasmic reticulum may have a pathophysiological significance in contributing to altered hepatic metabolism during septic shock.

Adenosine Triphosphate↗
PubMed1995

Ophthalmoplegia and facial numbness following treated squamous carcinoma of the forehead.

A 62-year-old man presented with progressive diplopia, left ptosis, proptosis, complete ophthalmoplegia, facial numbness, and headache of 2 1/2 months' duration. The symptoms started 1 month after surgical resection of a squamous cell carcinoma in the left side of the forehead. Imaging studies helped localize the lesion, correlating with clinical features. The differential diagnosis is discussed. The final diagnosis was confirmed by autopsy.

Brain Neoplasms↗
PubMed1995

Comparison for four techniques of catheter insertion in patients undergoing continuous ambulatory peritoneal dialysis.

OBJECTIVE: To compare four different ways of implanting catheters for continuous ambulatory peritoneal dialysis (CAPD) in an effort to reduce the incidence of complications. DESIGN: Retrospective study. SETTING: Teaching hospital, Taiwan. SUBJECTS: 166 Patients who had 180 catheters inserted between 1985 and 1993. INTERVENTIONS: 49 Catheters were inserted through midline incisions (in 24 of which the catheter was fixed with an additional suture) and 131 were inserted through paramedian incisions (in 88 of which the catheter was fixed with an additional suture). MAIN OUTCOME MEASURES: Morbidity, particularly the incidence of migration of the catheter and incisional hernia. RESULTS: 8/68 Catheters migrated in patients in whom no additional fixing suture had been used, compared with 2/112 in whom an additional suture had been used (p = 0.007). There were 4 incisional hernias in 49 midline, compared with 0/131 paramedian, incisions (p < 0.0001). Significantly more catheters had to be removed after midline than after paramedian incisions (35/49 compared with 56/131, p = 0.0008); chi square for independence 15.02, df 3, p = 0.0018. CONCLUSION: For the implantation of catheters for CAPD the paramedian incision is associated with significantly fewer complications than the midline incision and the incidence is even lower if the catheter is fixed to the lower peritoneum with an additional suture.

Adolescent↗
PubMed1995

Clinical experience with hepatic resection for ruptured hepatocellular carcinoma.

BACKGROUND: Spontaneous rupture of a hepatocellular carcinoma (HCC) is an uncommon but fatal complication of this disease. Surgical treatment is aimed at controlling the intraperitoneal hemorrhage, which has been achieved by hepatectomy, hepatic arterial ligation, packing and suturing. However, hemostasis obtained by hepatic arterial ligation, packing and suturing is not particularly effective, and the rebleeding rate is high. Information on hepatectomy for ruptured HCC is sparse, and we therefore reviewed our experience with hepatic resection for this potentially fatal complication. METHOD: The clinicopathological features of 23 patients with ruptured HCC who underwent hepatectomy during the past 15 years were reviewed. Morbidity, mortality and survival rates were analyzed. RESULTS: Effective hemo-stasis was achieved by hepatectomy. Indications for operative treatment were acute abdomen necessitating immediate laparotomy in 12, and spontaneous hemoperitoneum in 11. Types of hepatectomy included left hemihepatectomy in 3, lateral segmentectomy in 6 and local excision in 14. Liver cirrhosis was the concomitant disease in 13 (56.5%). Hospital mortality rate was 4.3%. 1, 2, 3, and 5 year survival rates were 60%, 52%, 40.5% and 26.5%, respectively. CONCLUSIONS: Hepatic resection is the treatment of choice for ruptured HCC. Long-term survival can be observed in a few patients without recurrence.

Adolescent↗
PubMed1995

Density of muscarinic receptors in rat myocardium during early sepsis.

The muscarinic receptor changes in two subcellular fractions of rat myocardium during sepsis, the sarcolemma (SL) and light vesicles (LV), were studied. [3H]-quinuclidinyl benzilate ([3H]-QNB) was used as a radioligand. Sepsis was induced by cecal ligation and puncture (CLP). The septic rats had higher pulse rates and slightly higher blood glucose levels than control rats. The marker enzyme assays revealed that the SL fraction was enriched with 5'-nucleotidase and the Na(+)-K(+)-ATPase activity increased over 20-fold, while the LV fraction showed very little enrichment when compared with the homogenate. [3H]-QNB binding studies showed that Bmax increased by 58.8% in SL with no changes in LV during early sepsis (9 h post-CLP), but there was no significant change in the Kd value. These data indicate that muscarinic cholinergic receptors in rat heart SL increase during early sepsis. Since the muscarinic cholinergic receptors mediate parasympathetic modulation of myocardial contractility, changes in the number of muscarinic receptors in the cardiac SL may have a pathophysiologic significance in the development of hemodynamic changes during sepsis.

Animals↗
PubMed1994

Vaninolol: a new selective beta 1-adrenoceptor antagonist derived from vanillin.

The beta-adrenoceptor blocking properties of vaninolol ((+/-)4-[4'-(2-hydroxy-3-tert-butyl-aminopropoxy)-3'-methoxyphenyl]- 3-buten-2-one), derived from vanillin, were first investigated under in vivo and in vitro conditions. Vaninolol (0.1, 0.5, 1.0 mg/kg, i.v.), as well as propranolol, produced a dose-dependent bradycardia response and a sustained pressor action in urethane-anesthetized normotensive rats. Vaninolol inhibited the tachycardia effects induced by (-)isoproterenol, but had no blocking effect on the arterial pressor responses induced by phenylephrine. These findings suggested that vaninolol possessed beta-adrenergic blocking activity, but was without alpha-adrenergic blocking activity. In isolated guinea-pig tissues, vaninolol antagonized (-)isoproterenol-induced positive inotropic and chronotropic effects of the atria and tracheal relaxation responses in a concentration-dependent manner. The parallel shift to the right of the concentration-response curve of (-)isoproterenol suggested that vaninolol was a beta-adrenoceptor competitive antagonist. The effect of vaninolol was more potent on the atria than on tracheal tissues, indicating it had some beta 1-adrenoceptor selectivity. On the other hand, the order of the hydrophilicity was atenolol >> vaninolol > propranolol. In addition, vaninolol had a mild direct cardiac depression at high concentrations and was without intrinsic sympathomimetic activity (ISA). Furthermore, binding characteristics of vaninolol and other beta-adrenoceptor antagonists were evaluated in [3H]dihydroalprenolol binding to guinea-pig ventricular membranes. The order of potency of beta-adrenoceptor antagonists in competing for the binding sites was (-)propranolol >> vaninolol > or = atenolol. In conclusion, vaninolol was found to be a selective beta 1-adrenoceptor antagonist with relatively low lipophilicity in comparison with propranolol, devoid of ISA, and had a mild myocardial depressant effect.

Adrenergic beta-1 Receptor Antagonists↗