Prevalence of liver injury associated with dimethylformamide (DMF) exposure was determined. Medical examinations, liver function tests, and creatine phosphokinase (CPK) determinations were performed on 183 of 204 (76%) employees of a synthetic leather factory. Air concentrations of solvents were measured with personal samplers and gas chromatography. The concentration of DMF in air to which each worker was exposed was categorized. High exposure concentrations of DMF (i.e., 25-60 ppm) were significantly associated with elevated alanine aminotransferase (ALT) levels (ALT greater than or equal to 35 IU/l), a result that did not change even after stratification by hepatitis B carrier status. Modeling by logistic regression demonstrated that exposure to high concentrations of DMF was associated with an elevated ALT (p = .01), whereas hepatitis B surface antigen (HBsAg) was slightly but independently associated with an elevated ALT (p = .07). In those workers who had normal ALT values, there occurred still significantly higher mean ALT and aspartate aminotransferase (AST) activities, especially among those who were not HBsAg carriers. A significant association existed between elevated CPK levels and exposure to DMF. However, an analysis of the CPK isoenzyme among 143 workers did not reveal any specific damage to muscles. This outbreak of liver injury among synthetic leather workers is ascribed to DMF. It is recommended that the occupational standard for DMF and its toxicity among HBsAg carriers be evaluated further.

Adult↗

PubMedDate not supplied

New method for exposing mammalian cells to intense laser radiation using the evanescent fields created in optical waveguides.

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Cell Line↗

PubMedDate not supplied

Laparoscopic subsegmentectomy for hepatocellular carcinoma with cirrhosis.

BACKGROUND/AIMS: Laparoscopic liver resection is feasible for both benign and malignant disease with today's laparoscopic techniques and technology. Location of the tumor at the edge of segment 3, 4, 5, or 6 of our patients makes them an ideal candidate for laparoscopic resection. METHODOLOGY: There were 9 patients who underwent laparoscopic subsegmentectomy for hepatocellular carcinoma with cirrhosis. They were classified as Child A in 6 and B in 3 patients. Hepatitis B was found in 5 and Hepatitis C in 4 cases. Preoperative diagnosis of hepatocellular carcinoma was completed in 7 and definitive histologic diagnosis from frozen section in 2 cases. All 9 patients underwent subsegmentectomy and removal of the tumor with non-tumor cirrhotic liver with a distance of 10 mm at the least margin. Laparoscopic ultrasound allows exact localization of lesions and achievement of adequate resection margin. RESULTS: Those patients resumed a full diet on the 2nd-3rd day after the operation and were discharged home on day 4-7 with no complications but one had prolonging discharge due to ascitis from a drainage tube. Finally, the ascitis was controlled by medications for 1 week. All patients had high postoperative satisfaction. CONCLUSIONS: Laparoscopic liver resection is a procedure of significant risk and technically demanding. Therefore, it should be performed only by experienced liver surgeons with a high level of laparoscopic skill and in the carefully selected patient.

Adult↗

PubMedDate not supplied

Elective radiation therapy for high-risk malignant melanomas.

PURPOSE: Local-regional recurrence rates of 30%-50% have been reported after resection of high-risk malignant melanomas (multiple node involvement, extracapsular spread, deep invasion, recurrent disease, and/or microscopically involved margins). Recently, we have been offering elective radiation therapy, after definitive surgery, to selected patients who have high-risk malignant melanomas. We herein report our initial results. PATIENTS AND METHODS: From 1993 to 1999, 40 patients who underwent surgery for high-risk malignant melanomas (multiple involved lymph nodes [21 patients]; close or microscopically involved surgical margins [nine patients]; extracapsular extension [six patients]; previously resected, recurrent disease [three patients]; and/or primary tumors more than 4 mm thick [four patients]) received elective radiation therapy. Thirty-six patients received 3000 cGy in five fractions (600 cGy per fraction given twice weekly), and four patients received 3600 cGy in six fractions. RESULTS: At a median follow-up of 18.4 months (range, 3.8-74.1 months), the actuarial 5-year local-regional control rate was 84%. Systemic recurrence rates in these patients were similar to those reported for this subset of patients, and the actuarial overall survival rate at 5 years was 39%. Acute toxicity was limited to erythema of the skin and, in one instance, probable cellulitis, with no late sequelae. DISCUSSION: Elective radiation therapy (600 cGy per fraction for five or six fractions) effectively controlled residual subclinical disease after surgery; however, better adjuvant systemic therapies need to be designed to eliminate distant metastases and to alter survival rates.

Adult↗

PubMedDate not supplied

[Contribution of the endogenous opioid system to regulation of heart resistance to the arrhythmogenic effect of short-term ischemia and reperfusio].

Preliminary selective blockade of micro, delta1, delta2, kappa1, and kappa2 opioid receptors proved to have no effect on the incidence of ventricular arrhythmias during a 10-min coronary occlusion and subsequent reperfusion in ketamine-anesthetized rats. We propose that the endogenous opioid system has no considerable role in regulation of heart resistance to the arrhythmogenic effect of short-term local ischemia and subsequent reperfusion.

Animals↗

PubMedDate not supplied

Inhibitory effects of phenolics on xanthine oxidase.

The stems of Bougainvillea spectabillis Wild (Nyctaginaceae) have been used in folk medicine against hepatitis. Spinasterol, 22, 23-dihydrospinasterol and caffeic acid were isolated from the plant stems and characterized. Caffeic acid has not been previously isolated from this plant but spinasterol has been isolated from the leaves. Caffeic acid was found to be the active principle exhibiting strong inhibition of xanthine oxidase in this study (IC50 = 39.21 microM). In order to study the structure-activity relationship of the phenolics as regards xanthine oxidase inhibition, twelve naturally occurring phenolics (esculetin, scopoletin, scoparone, barbaloin, berberine chloride, sinomenine, osthole, paeonol, honokiol, magnolol, methyleugenol and 6-gingerol) were tested for their inhibitory effects on xanthine oxidase. The results showed that esculetin displayed the strongest activity (IC50 = 28.4 microM), and induced competitive inhibition of the enzyme with respect to the substrate xanthine. The apparent inhibition constant (Ki) of esculetin was 2.369 x 10(-6) M. Since xanthine oxidase serum levels are increased in hepatic and brain tumors, caffeic acid and esculetin should be tested as anti-hepatitis or/and anticancer agents.

Anticarcinogenic Agents↗

PubMedDate not supplied

Inhibitory effects of flavonoids on xanthine oxidase.

The stems of Bougainvillea spectabillis Wild (Nyctaginaceae) have been used in folk medicine for hepatis, and spinasterol and quercetin were isolated and characterized from the plant leaves in this study. These constituents have not been previously isolated from Bougainvillea spectabillis W. Quercetin, the flavonoid, was found as active principle because it showed a strong activity on xanthine oxidase inhibition (IC50 = 7.23 microM) in this study as well as in the literature. Since xanthine oxidase serum levels are increased in hepatitis and tumoral brain tissues, quercetin may be used for remission of hepatitis or brain tumor. In order to study the structure-activity relationship of the flavonoids as regards xanthine oxidase inhibition, nine naturally occurring flavonoids have been tested the inhibitory effects on xanthine oxidase, such as baicalein, baicalin, capillarisin, d-catechin, d-epicatechin, hesperidin, liquiritin, puerarin and wogonin. The results showed that baicalein displayed the strongest activity (IC50 = 9.44 microM), followed by wogonin (IC50 = 52.46 microM) and then baicalin (IC50 = 71.73 microns). Baicalein induced uncompetitive inhibition of the enzyme with respect to xanhtine and the apparent inhibition constant (Ki) was 2.48 x 10(-6) M.

Drugs, Chinese Herbal↗

PubMedDate not supplied

Structure-activity relationship of coumarins in xanthine oxidase inhibition.

Esculetin(4), umbelliferone(7-hydroxycoumarin)(3) and 7-hydroxy-4-methyl coumarin(8) are strong xanthine oxidase inhibitors (IC50 = 20.91, 43.65 and 96.70 microM respectively). Based on this observation, the structure of 7-hydroxy coumarin(3) plays a very important role in xanthine oxidase (XO) inhibition. The 6-hydroxy group present in the molecule of 7-hydroxy coumarin, e.g. esculetin(4) enhanced the activity, whereas substitution by the 6-methoxy group, e.g. scopoletin (5), reduced the inhibitory effect. Furthermore, 6-glycoside group present in the molecule of 7-hydroxy coumarin, e.g. esculin (6,7-dihydroxy coumarin 6-glucoside)(12) strongly decreased the inhibitory effect as well as scoparone(6), the fully methylated derivative of esculetin (4). In contrast to 7-hydroxy coumarin(3), however, 4-hydroxy coumarin(13) showed only a weak effect on XO inhibition. 4-Substituent present in the molecule of 7-hydroxycoumarin also reduced the activity but the degree of reduction depended on the substituents: 7-hydroxy-4-methylcoumarin (8) < 7-hydroxycoumarin-4-acetic acid (7) < 7-hydroxy-4-trifluoromethylcoumarin (9). Their percent inhibition at 100 microM was 62.47, 38.46 and 26.84% respectively. 8-substituent present in the molecule of 7-hydroxy coumarin (3), such as 7,8-dihydroxy-6-methoxycoumarin(10) and fraxin(7-hydroxy-6-methoxycoumarin 8-glucoside)(11) reduced the activity as compared with scopoletin (5). Their percent inhibition at 100 microM was 18.4 and 6.9% respectively, which indicated that the more bulky the 8-substituted in the structure, the weaker the inhibitory activity on XO. 3,4,8-Trimethyl-7-hydroxycoumarin(14) which substitution by the methyl at 3,4 & 8 in the structure of 7-hydroxycoumarin(3) also reduced the activity as compared with 7-hydroxycoumarin(3). It seems that the double bond in the structure of coumarin(1) played an important role in the activity as compared with coumarin(dihydrocoumarin)(2). The apparent inhibition constants(Ki) of esculetin(4), umbelliferone (3) and 7-hydroxy-4-methylcoumarin(8) were 2.056, 21.683 and 4.86 microM respectively and induced competitive, uncompetitive and a mixed type of inhibition of the enzyme with respect to the substrate xanthine.

Coumarins↗

PubMedDate not supplied

Inhibitory effects of phenolic carboxylic acid analogues on xanthine oxidase.

Nineteen phenolic carboxylic acid analogues were tested for the effects on xanthine oxidase inhibition. 2,2',4,'4'-Tetrahydroxybenzophenone and 2,3,4-trihydroxybenzoic acid displayed the strongest activities (IC50 = 38.70 microM, IC50 = 90.16 microM respectively). Their apparent inhibition constants (Ki) were 7.052 and 0.535 microM respectively, and induced mixed type and competitive type inhibitions respectively with respect to the substrate xanthine.

Aldehyde Reductase↗