Pattern of medical care services utilization in Fiji

The present study was designed to analyze sociodemographic and health related factors that influence the utilization of medical care services in Fiji by using the method of discriminant function. Some sociodemographic and health related independent variables had significant effects on the two patterns of modern and traditional medical services utilization. Discriminant function coefficients for sex, age and race are large enough to suggest the importance of discriminating between two patterns of medical care utilization. This suggests that traditional medical service is coexistent with modern medicine in Fiji and might play an extremely important role in providing health care for rural communities in the same way as modern medicine.

Uptake of bicarbonate/CO2 in the isolated guinea pig placenta

Experiments were performed to investigate the mechanisms of bicarbonate/CO2 transport in the isolated guinea pig placenta. The maximal uptake of [14C]-bicarbonate/CO2 (reference [3H]-L-glucose) was about 60 per cent on both the fetal and maternal side, using the method of paired tracer single injection dilution technique. Carbonic anhydrase inhibitors such as acetazolamide (0.1 and 1 mmol/l) and the poorly permeant aminothiadiazole (0.5 mmol/l) reduced bicarbonate/CO2 uptake on both sides by 25-50 per cent. Inhibition was significantly higher on the fetal side. When lactate (5 mmol/l) was added to the acceptor side solution, the uptake of bicarbonate/CO2 increased 10-20 per cent. DIDS (1 mmol/l) decreased bicarbonate/CO2 uptake additionally under the simultaneous influence of acetazolamide. It is concluded that at least two mechanisms for placental bicarbonate transfer exist. A portion of bicarbonate, predominantly on the fetal side and outside the trophoblastic cells, is converted to CO2 which then diffuses into the tissue and crosses the placental barrier. Another part of bicarbonate is transported as ion using an anion exchange system, which exists in both the multivillous and the basal membranes of the syncytium. The first system is important for the excretion of fetal CO2 into the mother.

[Mercury concentration in gray hair]

Scalp hair sample were collected from 20 gray-haired males and 7 gray-haired females. Two hair samples, one each of dark hair and gray hair, obtained from each individual were selectively analysed for organic and inorganic mercury concentrations. The following finding were made: 1) In both sexes, total and organic mercury concentrations were significantly higher in gray hair than in dark hair but no difference was observed between dark hair and gray hair for the concentration of inorganic mercury. 2) For males, no significant differences between dark hair and gray hair were found for total, organic or inorganic mercury concentrations. On the other hand, gray hair had significantly higher levels of total, organic and inorganic mercury concentrations than dark hair in females. 3) When comparison was made between the sexes, total, organic and inorganic mercury concentrations were significantly higher in males than in females for dark hair. For gray hair, however, significantly higher levels of total and organic mercury concentrations, but not of inorganic mercury concentrations, were found in males. 4) The proportion of inorganic mercury to total mercury was higher in females than in males for both dark and gray hair. It was also higher in gray hair than in dark hair for females.

Induction of Fc and C3b receptors on rabbit corneal cells by herpes simplex virus

The expression of receptors for Fc portion (FcR) of immunoglobulin G (IgG) and for a C3b component of complement (C3bR) by herpes simplex virus (HSV) was studied in primary cultures of rabbit corneal cells. Monolayer cultures of epithelial, stromal and endothelial cells of the rabbit cornea were infected with three strains each of type 1 (HSV-1) and type 2 HSV (HSV-2). Rosette methods were used to detect receptors by means of sheep erythrocytes sensitized with rabbit IgG for FcR and C3b-coated sheep erythrocytes for C3bR. The FcR were expressed regularly on epithelial, stromal and endothelial cells by all three strains of both HSV-1 and HSV-2. The C3bR, however, were expressed only by HSV-1 on epithelial and stromal cells. Little or no C3bR activities could be detected on endothelial cells infected with any strain of HSV-1 or HSV-2. The FcR and C3bR expressed on corneal cells were induced by HSV and were blocked by monoclonal antibody to HSV-1 glycoprotein E(gE) or glycoprotein C(gC) respectively, confirming findings of other investigators that gE acts as FcR and gC as C3bR.

Halothane hepatotoxicity and reductive metabolism of halothane in acute experimental liver injury in rats

Reductive metabolism of halothane was measured after acute liver injury induced by galactosamine (1.0 g/kg, IP) in rats. On the seventh day of liver injury, when previously elevated serum alanine aminotransferase levels had returned to near normal range, anaerobic release of fluoride from halothane by hepatic microsomes, which appears to reflect the reductive pathway of halothane metabolism, was still remarkably decreased (1.36 +/- 0.56 nmol/mg protein/h vs 5.88 +/- 0.58 in controls, P less than 0.001). In another set of experiments, rats (n = 8) given galactosamine 7 days earlier and saline-treated control rats were given halothane anesthesia (1.0%) under mildly hypoxic conditions (F1O2 0.14). In saline controls, halothane anesthesia resulted in a mild but statistically significant increase in serum alanine aminotransferase levels (32 +/- 4 vs 59 +/- 6 U/ml, P less than 0.001). In contrast, serum levels of this enzyme were not changed by halothane anesthesia in galactosamine-treated rats (45 +/- 3 vs 49 +/- 4 U/ml). Although care should be taken in extrapolating the importance of these animal data to humans, the results of this study suggest that halothane hepatotoxicity can be attenuated in the presence of minor liver injury as a result of decreased hepatic biotransformation of the anesthetic. The data support the view that halothane anesthesia is not necessarily contraindicated in subjects with impaired liver function.

Experimental portal fibrosis produced by intraportal injection of killed nonpathogenic Escherichia coli in rabbits

An attempt was made to develop an animal model for the study of the etiology of noncirrhotic portal fibrosis or idiopathic portal hypertension based on the assumption that it is related to chronic abdominal infection. Rabbits were given killed nonpathogenic Escherichia coli intraportally or intravenously. The animals to which a mixture of killed E. coli and rabbit antiserum (aggregated E. coli) was given intraportally developed remarkable histologic changes in the liver. The early inflammatory reactions in the portal area and parenchyma were followed by rapid disappearance of inflammation and development of portal fibrosis with bile duct proliferation. Three intraportal challenges with aggregated E. coli were sufficient to produce pronounced portal fibrosis, although there was considerable variation in response among individual animals. This procedure also produced splenomegaly, and in some animals marked portal hypertension. Injection of nonaggregated killed E. coli into the portal vein or aggregated E. coli into the ear vein also caused similar hepatic changes, but they were milder in degree. These histologic changes resemble portal fibrosis seen in idiopathic portal hypertension and, less closely, pericholangitis associated with inflammatory bowel disease in humans.

Effects of vasopressin on portal hemodynamics in patients with portal hypertension

In view of the variability in the magnitude of the response of portal venous pressure to vasopressin in man, we investigated the effect of vasopressin on portal hemodynamics in seven patients with portal hypertension by simultaneous catheterization of the portal and the hepatic vein and the measurement of portal venous flow by an echo-Doppler flowmetry. Infusion of vasopressin (0.3 U/min) significantly decreased portal venous pressure (-36%), the gradient between portal venous pressure and free hepatic venous pressure (-50.6%), and portal venous flow (-54.3%) but did not reduce mean arterial pressure and pulse rate. Thus, vasopressin seems to decrease portal venous pressure by reducing portal venous flow.

Effect of neuraminidase on Fc and C3b receptors on rabbit corneal cells infected with herpes simplex virus

The effect of neuraminidase on Fc receptors (FcR) and C3b receptors (C3bR) was studied in epithelial, stromal and endothelial cells of the rabbit cornea infected with type 1 (HSV-1) and type 2 herpes simplex virus (HSV-2) in vitro. FcR were induced on epithelial, stromal and endothelial cells of the rabbit cornea by both HSV-1 and HSV-2, but their activities were not enhanced by neuraminidase. On the other hand, the treatment of HSV-infected corneal cells with neuraminidase resulted in the enhancement of C3bR activities on epithelial, stromal and endothelial cells infected with HSV-1, and the enhancing effect of neuraminidase was more pronounced on corneal endothelial cells. A similar neuraminidase treatment had no significant effect on C3bR activities on the corneal cells infected with HSV-2.

Effects of anticonvulsant agents on halothane-induced liver injury in human subjects and experimental animals

In order to evaluate the clinical implication of experimental studies on halothane-induced liver damage in phenobarbital-treated rats, we studied the clinical records of 315 consecutive patients who underwent brain surgery with halothane anesthesia. After exclusion of subjects with a history of alcoholism or antecedent chronic liver disease, clinical data of 279 patients with normal preoperative transaminase activities were analyzed. The incidence of halothane-induced liver injury was significantly higher in the subjects given phenobarbital than in those with no phenobarbital medication (7/100 vs. 1/179, p less than 0.01). To determine if other anticonvulsant compounds can influence halothane-induced liver injury, rats were pretreated with diphenylhydantoin or valproic acid prior to exposure to halothane under hypoxic conditions for comparison with phenobarbital. The degree of halothane hepatotoxicity assessed from ALT activities and morphological alterations was of the decreasing order of phenobarbital greater than controls = diphenylhydantoin greater than valproic acid, and a similar order was observed in the extent of reductive metabolism of halothane. These results indicate that patients pretreated with phenobarbital may be at a greater risk of halothane-induced liver damage, and that treatment with valproic acid and diphenylhydantoin lead to the production of toxic intermediates of halothane to a lesser extent than treatment with phenobarbital does.

Effects of neonatal administration of monosodium glutamate on plasma growth hormone (GH) response to GH-releasing factor in adult male and female rats

Female and male rats were treated with monosodium glutamate (MSG; 4 mg/g b. wt.) as neonates and the capability of the pituitary gland to secrete growth hormone (GH) in response to an intravenous injection of human GH-releasing factor (GRF) was evaluated under pentobarbital anesthesia on 109 days of life. Immunoreactive GRF content in the pituitary stalk-median eminence tissue in MSG-treated rats was less than 20% of that of control. A significant dose-dependent plasma GH response was observed after the administration of two doses of human GRF (0.25 and 1 microgram/kg b. wt., i.v.) in both control and MSG-treated rats. The responses between MSG-treated and control rats were comparable in female rats, but they were significantly reduced in male MSG-treated rats. These results show that the pituitary's responsiveness to exogenous GRF is well preserved in MSG-treated rats despite prolonged and severe depletion of endogenous GRF and there exists a sex difference in the effect of MSG on GH secretion elicited by GRF.

Effects of hypoxia and phenobarbital treatment on the metabolism of mitomycin C in experimental animals

To evaluate the effects of anaerobic conditions and inducers for the mixed-function oxidase system on the metabolism of mitomycin C, a bioreductive alkylating agent widely used for the treatment of hepatocellular carcinoma, experiments so designed were performed in rats and mice. Metabolism of mitomycin C by microsomes from normal rat liver and diethyl-nitrosamine-induced mouse hepatocellular carcinoma tissue was assessed from the disappearance of the quinone portion of mitomycin C and by measurement of alkylating metabolites using 4-(p-nitrobenzyl)pyridine as a trapping agent. The metabolism of mitomycin C measured by the two independent methods was strikingly increased under anaerobic conditions in both intact and tumor tissues. Since involvement of cytochrome P-450 in the metabolic activation of mitomycin C was shown recently, effects of representative inducers for the mixed-function oxidase system on the metabolism of mitomycin C were also studied. Phenobarbital treatment resulted in a significant increase in the metabolism of mitomycin C in both intact and tumor tissues under anaerobic conditions. The markedly enhanced formation of active metabolites of mitomycin C under anaerobic conditions may explain on a metabolic basis, at least in part, our recent clinical observations that chemoembolizations with microcapsular forms of mitomycin C is more effective than conventional bolus administration of this agent in the treatment of hepatocellular carcinoma. Combination of anaerobic conditions and induction of the mixed-function oxidase system may be applicable to chemotherapy of hepatic malignancy.