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Biomedical subjects

H C Lin

Publications and source records attributed to H C Lin.

At least 415 records · Page 23Linked to original sources
PubMed1977

Electrophilic mercuration and thallation of benzene and substituted benzenes in trifluoroacetic acid solution.

The mercuration and thallation of benzene and substituted benzenes was studied with mercuric and thallic trifluoroacetate, respectively, in trifluoroacetic acid. With the shortest reaction time (1 sec) at 0 degrees , the relative rate of mercuration of toluene compared to that of benzene was 17.5, with the isomer distribution in toluene of: ortho, 17.4%; meta, 5.9%; and para, 76.7%. The isomer distribution in toluene varied with the reaction time, significantly more at 25 degrees than at 0 degrees . The competitive thallation of benzene and toluene with thallic trifluoroacetate in trifluoroacetic acid at 15 degrees showed the relative rate, toluene/benzene, to be 33, with the isomer distribution in toluene of: ortho, 9.5%; meta, 5.5%; and para, 85.0%. With increasingly higher reaction temperatures in both mercuration and thallation reactions of aromatics, isomerization (both intramolecular and intermolecular) within the relevant ortho- and para-metallated intermediate ions and/or of the isomers becomes more important. Competitive rates and isomer distributions of mercuration and thallation of benzene and substituted benzenes were also determined. The predominant para substitution in both mercuration and thallation of methylbenzenes reflects, besides some steric factors, the strong stabilizing effect of para methyl groups on the arenium ion intermediates. Under predominantly kinetically controlled conditions, no anomalous increase in the amount of meta substitution was observed.

Journal Article↗
PubMed1976

Multiple factor analysis of the action of local anesthetics.

The pH jump data of Bianchi and Strobel [(1968) Trans. N.Y. Acad. Sci. Ser. II, 30, 1082-1092] on desheathed frog sciatic nerve are fitted to rate equations. A general quantitation of synergism, summation, and antagonism of anesthetics and of excitation is given.

Action Potentials↗
PubMedDate not supplied

Utility of sonographic gallbladder wall patterns in differentiating malignant from cirrhotic ascites.

Thirty-one patients with ascites associated with malignancy and 49 patients with cirrhotic ascites were enrolled in a sonographic study of the gallbladder wall. Three gallbladder wall patterns were recognized: A, single-layered, nonthickened wall; B, single-layered, thickened wall; and C, double-layered, thickened wall. Pattern A was found more frequently in patients with malignant ascites, while patterns B and C were detected more frequently in patients with cirrhotic ascites. If "nonthickened gallbladder wall" is used as a criterion for prediction of malignant ascites, the sensitivity is 80.6% and the specificity 93.9%. This suggests that sonographic examination of the gallbladder wall is useful in the differentiation of malignant from cirrhotic ascites.

Ascites↗
PubMedDate not supplied

Paroxysmal nocturnal hemoglobinuria presenting as moyamoya syndrome.

We report an 11-year-old girl who has paroxysmal nocturnal hemoglobinuria (PNH) and was admitted because of recurrent cerebrovascular accidents (CVA) and intermittent hemoglobinuria. Internal carotid angiography revealed bilateral typical moyamoya patterns. Although CVA due to arterial thrombosis may occur in PNH, the basal moyamoya vessels were never mentioned in case reports yet. The moyamoya syndrome has been reported in a variety of diseases and represents the nonspecific response to an impairment of arterial flow at specific sites in the brain. Our case discloses that PNH may present as moyamoya syndrome.

Cerebral Angiography↗
PubMedDate not supplied

Isolation and bioactivity of new tanshinones.

Two new diterpenoids, designated neocryptotanshinone and isotanshinone IIB, have been isolated from "Tan-Shen," the root of Salvia miltiorrhiza, together with a known compound, danshexinkun A. Their structures are established by spectral and physical data. Isotanshinone IIB exhibits significant inhibitory activity in vitro on ADP- and collagen-induced aggregation.

Abietanes↗
PubMedDate not supplied

A randomized controlled study of low-dose and high-dose terlipressin in the control of acute oesophageal variceal haemorrhage.

A randomized controlled trial was designed to investigate whether a high dose of terlipressin could control acute variceal haemorrhage more effectively than a low dose of terlipressin. Forty cirrhotic patients with bleeding oesophageal varices were included, with low-dose terlipressin in 21 patients and high-dose terlipressin in 19 patients. The two groups of patients were similarly matched for all parameters on admission. High-dose terlipressin (84%) seemed to be more effective in the initial control of bleeding than low-dose terlipressin (67%); however this difference was not significant. Complete control of bleeding during 24 h of drug infusion was achieved in 53% of patients receiving high-dose terlipressin and in 48% of those treated with low-dose terlipressin (P greater than 0.05). There were no major complications in either group. Mortality in relation to variceal bleeding and transfusion requirements were similar in the two groups. This study shows that high dose terlipressin is not superior to low dose terlipressin in acute variceal bleeding.

Aged↗
PubMedDate not supplied

Snake skin pattern gastropathy in cirrhotic patients.

Gastric mucosal lesions are common in patients with cirrhosis. Among them, snake skin pattern gastropathy (SSPG) is the most distinguishing one. A prospective study was conducted to investigate the incidence of SSPG in cirrhotic patients, the relationship between the degree of portal pressure and SSPG, and the possible association of SSPG with serum levels of gastrin and pepsinogen I. SSPG was found to be significantly more common in 100 cirrhotic patients than in 100 age- and sex-matched healthy controls (41% vs 0%, P less than 0.0001). Hepatic venous pressure gradient and serum gastrin and pepsinogen I levels were measured in 21 cirrhotic patients with SSPG and 25 cirrhotics without SSPG. There was no significant difference in hepatic venous pressure gradient (16.1 +/- 4.4 mmHg vs 16.1 +/- 4.9 mmHg, P greater than 0.05), serum gastrin level (78.0 +/- 26.7 pg/mL vs 80.1 +/- 32.5 pg/mL, P greater than 0.05) and serum pepsinogen I level (69.5 +/- 26.6 ng/mL vs 65.2 +/- 26.1 ng/mL, P greater than 0.05) in cirrhotic patients with or without SSPG. In conclusion, SSPG is common in cirrhotic patients. Portal pressure per se may not be the only factor causing SSPG--other aggressive factors may be needed together to cause the gastropathy. There is no evidence of correlation between serum gastrin or pepsinogen I level and SSPG.

Female↗
PubMedDate not supplied

Prevalence of anti-HCV among Chinese patients with acute and chronic liver disease.

To assess whether the hepatitis C virus plays an important role in Chinese patients with acute and chronic liver disease, antibodies to HCV (anti-HCV) were measured by enzyme immunoassay in 67 patients with type A and B acute viral hepatitis, 165 patients with non-A, non-B (NANB) hepatitis, 438 patients with chronic hepatitis, 200 patients with postnecrotic liver cirrhosis, 72 patients with alcoholic liver disease, 55 patients with non-alcoholic fatty liver, 24 patients with toxic and drug-induced hepatitis, and 20 patients with other chronic liver diseases. Anti-HCV was not detected in sera from patients with type A and B acute viral hepatitis, toxic and drug-induced hepatitis, primary biliary cirrhosis, Wilson's disease, or lupoid hepatitis. The anti-HCV prevalence was found to be highest in patients with NANB hepatitis (59% in sporadic and 73.2% in transfusion-associated), 16.4% in non-alcoholic fatty liver, 5.6% in alcoholic liver disease, 6.8% in chronic hepatitis, and 16% in postnecrotic liver cirrhosis. In patients with chronic hepatitis, the anti-HCV prevalence was significantly higher in HBsAg-negative (15/34, 44.1%) than in HBsAg-positive cases (15/404, 3.7%; P less than 0.0001). The results indicate that HCV is a major agent of NANB hepatitis and plays an important role in HBsAg-negative chronic liver disease in Taiwan.

Acute Disease↗
PubMedDate not supplied

Changes of hepatic and systemic haemodynamics following somatostatin administration in patients with hepatitis B-related cirrhosis.

Somatostatin has been used to effectively control acute variceal haemorrhage, with conjectured mechanisms on portal hypertension. We, therefore, evaluated the effects of somatostatin on hepatic and systemic haemodynamics in 15 patients with hepatitis B-related cirrhosis and portal hypertension. All patients received an intravenous, continuous infusion of somatostatin 250 micrograms/h, following a bolus injection of 250 micrograms. In systemic haemodynamics, the mean arterial pressure (MAP) increased (P < 0.05), associated with a reflex bradycardia within 3 min following bolus injections, compared with basal values. The right atrial pressure, pulmonary capillary wedge pressure, inferior vena cava pressure, cardiac index, and systemic vascular resistance remained unaffected after drug infusion. In hepatic haemodynamics, the wedge hepatic vein pressure remained unchanged after drug administration. However, there was an increase in free hepatic vein pressure (FHVP; P < 0.05), and a trend toward a decrease in the hepatic vein pressure gradient (HVPG; P = 0.063), within 3 min after bolus injection. Furthermore, the hepatic blood flow decreased significantly at 10 and 30 min after somatostatin infusion (P < 0.05). The effective sinusoidal perfusion assessed by indocyanine green infusion also decreased progressively at 10 min (P = 0.057) and 30 min (P < 0.05). We concluded that somatostatin, at the dose used in this study, caused a transient and bolus-related vasoconstrictive effect, resulting in increases in MAP and FHVP, a decrease in heart rate, and a trend toward lower HVPG. In addition, somatostatin reduced the hepatic blood flow and effective sinusoidal perfusion which may be hazardous to cirrhotic patients during variceal haemorrhage.

Female↗
PubMedDate not supplied

Measurement of intravariceal pressure by fine needle direct puncture in hepatitis B surface antigen-positive cirrhotic patients: the effect of vasopressin.

The pressure of oesophageal varices was determined by fine needle direct puncture in 19 patients with hepatitis B surface antigen (HBsAg)-positive cirrhosis after the first episode of variceal bleeding before endoscopic sclerotherapy. Both the stability and reliability of the measurement of intravariceal pressure by fine needle puncture were confirmed. Seven patients received intravenous 1 mL normal saline. Intravariceal pressure did not change before and after injection of normal saline (16.3 +/- 4.0 vs 16.0 +/- 4.0 mmHg, P > 0.05). Twelve patients received intravenous 1 units vasopressin and this caused a significant reduction in intravariceal pressure (15.6 +/- 2.6 vs 10.3 +/- 2.9 mmHg, P < 0.0001). The average basal intravariceal pressure in these patients was 15.8 +/- 3.1 mmHg. After intravariceal pressure was recorded, the needle was left in situ and endoscopic sclerotherapy commenced immediately. During the investigation, no adverse reaction or complication was encountered. It was concluded that the measurement of intravariceal pressure by fine needle direct puncture followed by immediate sclerotherapy is a safe and simple method to evaluate the short-term effect of drug prevention from oesophageal variceal bleeding and that vasopressin causes reduction of intravariceal pressure.

Aged↗
PubMedDate not supplied

Hepatitis D virus infection among prostitutes in Taiwan.

Two hundred and sixty-three adult licensed, 233 adult and 157 teenage unlicensed prostitutes from Taiwan were studied for prevalence and risk factors of hepatitis D virus (HDV) infection. The hepatitis B carrier rate among the three groups was 21, 15 and 20%, respectively, not significantly different from that of the general population in this area. However, the prevalence of HDV infection among carrier prostitutes was 55, 36 and 16%, respectively, much higher than that in general hepatitis B carriers. Univariate analysis revealed that the history of conducting paid sex for more than 12 months (P < 0.03), ear-piercing (P < 0.02), tattooing (P < 0.02), and gonorrhoea or syphilis (P < 0.005) were significant factors associated with HDV infection among these subjects. Multivariate analysis revealed that the history of ear-piercing and venereal diseases (P < 0.001) were still significant. In summary, genital ulcers caused by venereal diseases due to frequent sexual contact with multiple partners, and use of unsterilized needles in ear-piercing or tattooing play important roles in the high prevalence of HDV infection in prostitutes.

Adolescent↗
PubMedDate not supplied

Relationships between the severity of cirrhosis and haemodynamic values in patients with cirrhosis.

The relationship between the severity of cirrhosis and systemic and hepatic haemodynamic values was evaluated in 193 patients with cirrhosis, most of whom were diagnosed with post-necrotic cirrhosis. It was found that the hepatic venous pressure gradient and cardiac output in Pugh's A patients (13.6 +/- 4.8 mmHg and 6.2 +/- 1.6 L/min, mean +/- s.d.) were significantly lower than in both Pugh's B (16.8 +/- 4.3 mmHg and 7.3 +/- 2.1 L/min) and Pugh's C (18.8 +/- 5.5 mmHg and 7.4 +/- 2.3 L/min) patients (P < 0.01), respectively. In contrast, the systemic vascular resistance in Pugh's A patients (1232 +/- 369 dyn/s per cm5) was significantly higher than in both Pugh's B (1016 +/- 345 dyn/s per cm5) and Pugh's C (935 +/- 234 dyn/s per cm5) patients (P < 0.01), respectively. Additionally, not only was there a positive correlation found between Pugh's score and cardiac output and hepatic venous pressure gradient, but a negative correlation was found between Pugh's score and systemic vascular resistance. It was also confirmed that the degree of portal hypertension and the hyperdynamic circulation were more severe in patients with ascites than in those without ascites. However, there were no statistically significant differences in hepatic venous pressure gradient among patients with F1, F2 and F3 esophageal varices (15.7 +/- 4.0, 17.0 +/- 4.8 and 18.0 +/- 4.8 mmHg, respectively). It is concluded that in those patients with cirrhosis, the severity of cirrhosis is closely related to the degree of the hyperkinetic circulatory state and portal hypertension.

Adult↗
PubMedDate not supplied

Prolonged bleeding time in cirrhotic patients: relationship to peripheral vasodilation and severity of cirrhosis.

A prolonged bleeding time (> 540 s), measured with a Simplate single template device, was found in 0% of 50 patients with chronic hepatitis and 38% of 154 cirrhotic patients. Cirrhotic patients with a prolonged bleeding time (n = 59) had lower platelet counts (P < 0.001) and a longer prothrombin time (P < 0.001) and activated partial thromboplastin time (P < 0.001) compared with cirrhotic patients with a normal bleeding time (n = 95). A weak but significant negative correlation existed between the bleeding time and platelet count in cirrhotic patients (n = 154, r = -0.3668, P < 0.001). Patients with decompensated cirrhosis had a longer bleeding time in comparison to patients with compensated cirrhosis (621 +/- 39 vs 478 +/- 27 s, respectively, P < 0.01). The prolonged bleeding time was also discovered in 25% of 83 cirrhotic patients with a platelet count > 80 x 10(9)/L and a prothrombin time < 17 s (usually taken as safe limits for invasive procedures). Twenty-seven of the 83 cirrhotic patients received a haemodynamic study by Swan-Ganz catheterization. A lower systemic vascular resistance was found in cirrhotic patients with an abnormal bleeding time than in cirrhotic patients with a normal bleeding time (844 +/- 57 vs 1171 +/- 60 dyne.s.cm-5, respectively, P < 0.001), whereas both groups had similar hepatic venous pressure gradient (16.2 +/- 1.2 vs 18.1 +/- 1.4 mmHg, respectively, P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Bleeding Time↗
PubMedDate not supplied

Transjugular liver biopsy: comparison with percutaneous liver biopsy.

A transjugular liver biopsy was performed on 60 patients. Specimens were successfully obtained from 57 (95%) patients. Specimens obtained from cirrhotic patients were frequently small-sized/fragmented. The wedge hepatic venous pressure and hepatic venous pressure gradient were higher in patients with small-sized/fragmented specimens than those with non-fragmented specimens (16.3 +/- 6.4 vs 12.3 +/- 4.9 and 10.9 +/- 6.2 vs 7.3 +/- 3.4 mmHg, P < 0.05, respectively). During the same period of time, percutaneous liver biopsies were consecutively performed on 277 patients. The liver specimens by transjugular method were generally smaller (0.63 +/- 0.58 vs 1.50 +/- 0.86 cm, P < 0.001) and more fragmented (63% vs 16%, P < 0.01) than those obtained by percutaneous method. Biopsy specimens obtained for diagnosis by the former method were inadequate from 6 (10%) patients and by the latter route were inadequate from 7 (2%) patients. Subcapsular haematoma in one patient was associated with the transjugular liver biopsy. Minor complications occurred in three patients: neck haematoma in two and paroxysmal supraventricular tachycardia during the procedure in one. In comparison, percutaneous liver biopsy was followed by minor complications in 20 patients and major complications in four patients. It is concluded that transjugular liver biopsy is a safe, valuable and alternative procedure to obtain liver specimens, especially in patients who were contraindicated for percutaneous liver biopsy.

Adult↗
PubMedDate not supplied

Total paracentesis in non-alcoholic cirrhotics with massive ascites: mid-term effects on systemic and hepatic haemodynamics and renal function.

Single total paracentesis (4.8-11 L) was performed in 23 patients with hepatitis B surface antigen (HBsAg)-positive cirrhosis and massive ascites and its effects on systemic and hepatic haemodynamics and renal function were examined over 5 days. Severe hypotension occurred in six (26.1%) patients from 6 to 54 h after paracentesis. In the remaining 17 patients, compared to the baseline, there was an increase in the cardiac output (6.1 +/- 0.3 vs 6.7 +/- 0.3 L/min, P < 0.001) and a decrease in right atrial pressure (8.8 +/- 0.8 vs 4.3 +/- 0.7 mmHg, P < 0.001), systemic vascular resistance (1160 +/- 61 vs 976 +/- 50 dyne.s.cm-5, P < 0.001), and wedged hepatic venous pressure 30 min after completion of paracentesis. After 5 days, right atrial pressure, systemic vascular resistance and wedged hepatic venous pressure returned to baseline, while the cardiac output dropped to a level lower than the baseline (5.7 +/- 0.7 L/min, P < 0.05). Hepatic venous pressure gradient had returned to baseline after 5 days. Serial tests of serum creatinine level showed an increase from day 3 (1.34 +/- 0.14 vs 1.04 +/- 0.10 mg/dL, P < 0.05). On day 5, creatinine clearance (55.7 +/- 5.4 vs 41.9 +/- 5.3 mL/min, P < 0.05) and effective renal plasma flow (351 +/- 32 vs 293 +/- 29 mL/min, P < 0.05) were decreased, compared to the baseline. Based on these data, infusion of a volume expander may be necessary for total paracentesis to avoid systemic haemodynamic complications in non-alcoholic cirrhosis.

Ascites↗