Lack of influence of recombinant human erythropoietin on parathyroid function in hemodialysis patients with secondary hyperparathyroidism

The effects of recombinant human erythropoietin (rHuEPO) treatment on parathyroid function in patients on maintenance hemodialysis (HD) with secondary hyperparathyroidism (HPT) is poorly understood. We compared the levels of serum intact parathyroid hormone (PTH) and the suppressibility of PTH by intravenous calcium infusion before and after 12 weeks of rHuEPO treatment in 8 HD patients with secondary HPT. The suppressibility of PTH by calcium infusion in HD patients was also compared with that of normal subjects. After rHuEPO treatment, in HD patients hematocrit and hemoglobin levels increased significantly from 20.1 +/- 1.3% and 6.65 +/- 0.46 g/dl to 28.7 +/- 1.0% and 9.68 +/- 0.39 g/dl, respectively. The serum intact PTH levels did not change significantly (541.9 +/- 65.3 pg/ml before versus 572.9 +/- 75.3 pg/ml after rHuEPO treatment), nor did serum ionized calcium, phosphate, magnesium, aluminum, alkaline phosphatase, and 1.25(OH)2D levels. Calcium infusion significantly increased serum ionized calcium and suppressed serum PTH levels. However, the increment in serum calcium levels and the percent decrement of serum PTH showed no significant differences before and after rHuEPO treatment in HD patients. Elevations in serum calcium levels during calcium infusions were not significantly different between normal subjects and HD patients. However, the percent maximal decrement in serum PTH level was less in HD patients both before and after rHuEPO treatment than in normal subjects (-75.4 +/- 3.9 and -76.4 +/- 4.1% versus -91.4 +/- 1.4%). We conclude that rHuEPO treatment has no influence on parathyroid function in maintenance HD patients with secondary HPT. In addition, PTH secretion is less suppressed by calcium infusion in the same group of patients.

Evaluation of sexual transmission in patients with chronic hepatitis C infection

BACKGROUND

The transmission of hepatitis C virus (HCV) by parenteral exposure is well documented. However, a proportion of patients with acute or chronic HCV infection have an unknown source of infection.

OBJECTIVES

The purpose of this study is to evaluate the role of sexual transmission in HCV infection.

STUDY DESIGN

68 patients (median age, 50 years) with chronic hepatitis C and their spouses were tested for the presence of antibody to HCV (anti-HCV) by multi-antigen and chimeric C25 antigen enzyme immunoassays and for HCV RNA by the polymerase chain reaction. Information on sexual activity and risk factors for HCV infection were obtained from all couples via a questionnaire.

RESULTS

All index patients were positive for both anti-HCV and HCV RNA. Antibody to HCV was detected in four (5.9%) of their spouses. One anti-HCV-positive spouse had a history of blood transfusion while the other three (4.4%, 95% CI = 1.5-12.2%) had no known risk factors for HCV infection and thus may have been exposed to HCV via sexual transmission. Two of these 3 spouses had positive serum HCV RNA and had identical HCV genotype to the index patients. The length of sexual exposure was significantly longer in the couples who both were anti-HCV-positive than in patients whose spouses were anti-HCV negative (median: 25 vs. 10 years, P = 0.02, Mann-Whitney test). In our 68 index patients, 96% had antibodies to the recombinant proteins from the C22 (core) and C33C (NS3) regions, and 82% and 76% had antibodies to the proteins from the NS5 and C100-3 (NS4) regions. Identical anti-HCV profiles were noted in two of the four anti-HCV-positive couples.

CONCLUSIONS

Our results indicate that sexual transmission, although uncommon, should be considered as a risk factor for HCV infection, especially in spouses who have had long-term intimate relationships with a chronic hepatitis C patient.

Minimum sample size estimation to detect gene-environment interaction in case-control designs

As genetic markers become more available, case-control studies will be increasingly important in defining the role of genetic factors in disease causality. The authors estimate the minimum sample size needed to assure adequate statistical power to detect gene-environment interaction. One assumption is made: the prevalence of exposure is independent of marker genotypes among controls. Given the assumption, six parameters (three odds ratios, the prevalence of exposure, the proportion of those with the susceptible genotype, and the ratio of controls to cases) dictate the expected cell sizes in a 2 x 2 x 2 table contrasting genetic susceptibility, exposure, and disease. The three odds ratios reflect the association between disease and 1) exposure among non-susceptibles; 2) susceptible genotypes among nonexposed individuals; and 3) the gene-environment interaction itself, respectively. Given these parameters, the number of cases and controls needed to assure any particular Type I and Type II error rates can be estimated. Results presented here demonstrate that case-control designs can be used to detect gene-environment interaction when there is both a common exposure and a highly polymorphic marker of susceptibility.

A randomized controlled trial of recombinant interferon alpha-2b in the treatment of Chinese patients with acute post-transfusion hepatitis C

To evaluate the efficacy of recombinant interferon alpha-2b in the treatment of patients with acute post-transfusion hepatitis C, a randomized controlled trial was conducted in 33 acute post-transfusion hepatitis C patients; 16 patients received 3 million units of subcutaneously injected recombinant interferon alpha-2b 3 times a week for 3 months and 17 patients without specific treatment were used as controls. At the end of the interferon treatment, 13 (81%) patients in the interferon-treated group normalized serum alanine aminotransferase compared with only six (35%) patients in the control group (p < 0.01). One year after completion of the interferon treatment, nine (56%) patients in the interferon-treated group and six (38%) patients in the control group normalized serum alanine aminotransferase (p = 0.35). Serum HCV-RNA measured by reverse transcription-polymerase chain reaction was positive in all patients at the time of enrollment and then became undetectable in 13 (81%) patients in the interferon-treated group and two (12%) patients in the control group at the end of interferon treatment (p < 0.001). One year after completion of the interferon treatment, seven (44%) patients in the interferon-treated group and two (13%) patients in the control group had persistent undetectable serum HCV-RNA (p = 0.08). Using a logistic regression model, the lower pretreatment level of serum HCV-RNA measured by quantitative branched DNA signal amplification assay was the only predictor for a favorable response to the interferon treatment in acute hepatitis C patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation of serum HCV RNA and alanine aminotransferase levels in chronic hepatitis C patients during treatment with ribavirin

To evaluate the effect of ribavirin on serum hepatitis C virus (HCV) RNA and alanine aminotransferase (ALT) levels, 22 patients with chronic HCV infection were treated with oral ribavirin 1200 mg daily in three divided doses for 4 weeks. At the end of 4 weeks treatment, the serum ALT decreased in all but one patient and became normal in three individuals. The mean pretreatment serum ALT was reduced significantly from 193 +/- 45 i.u./L to 95 +/- 16 i.u./L after 4 weeks therapy (P = 0.009). However, 8 weeks after cessation of treatment, the serum ALT rose to a mean value of 154 +/- 21 i.u./L. The mean pretreatment serum HCV RNA was not significantly decreased at the end of 4 weeks treatment (7.0 x 10(5) vs. 4.1 x 10(5) copies/mL, P > 0.05). However, serum HCV RNA levels were decreased in 12 and increased in 10 patients at the end of 4 weeks therapy. Eight weeks after cessation of therapy, the serum HCV RNA of 22 patients rose to a mean value of 4.9 +/- 10(5) copies/mL. Six patients who continued to have elevated serum ALT and positive HCV RNA after the initial 4 weeks treatment received oral ribavirin at the same dosage for an additional 24 weeks. The serum ALT again decreased in all six patients during therapy, but rose to pretreatment values by 8 weeks after cessation of the treatment. In addition, no significant changes were noted in the mean serum HCV RNA levels during and after 24 weeks of ribavirin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B virus infection in Asian Americans

This article summarizes studies on hepatitis B in the Asian American population and includes prevalence rates among different Asian subgroups, routes of transmission, and sequelae of both perinatal and childhood-acquired hepatitis B virus infection. Rationale for use of hepatitis B immune globulin and hepatitis B vaccine for Asian infants and vaccine for children and seronegative adults is discussed also. Chronic hepatitis B, cirrhosis, and primary hepatocellular carcinoma in adults and screening for early detection of liver cancer are reviewed.

Incidence of post-transfusion hepatitis before and after screening for hepatitis C virus antibody

To evaluate the effectiveness of screening test for antibody to hepatitis C virus (anti-HCV), the incidence of acute post-transfusion HCV infection in patients who underwent cardiovascular surgery and received blood transfusion was studied. All patients were followed prospectively with serum biochemistry tests and viral hepatitis markers before and periodically for at least 6 months after cardiovascular surgery. None of them had history of liver disease and none tested positive for anti-HCV prior to blood transfusion. Before blood donors were screened for anti-HCV with a second-generation HCV diagnostic kit, 28 (12.4%) of 226 patients or 0.49% of 5,690 unit transfusion had seroconverted to anti-HCV during a 6-month follow-up. The incidence of post-transfusion hepatitis (PTH) C in 91 patients who had received 1-12 units transfusion was significantly lower than in 135 patients who had received more than 12 units transfusion (6.6 vs. 16.3%, p < 0.05). However, none of the 87 transfused patients, since anti-HCV screening in July 1992, developed PTH C (p < 0.05). The result demonstrates that screening for anti-HCV by a more sensitive second-generation HCV diagnostic assay may protect the patients studied from PTH C. It further provides a firm argument for the necessity of a nation-wide blood donor screening.

Clinical evaluation of erythrocytosis in patients with hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignancy in southeast Asia and sub-Saharan Africa. During its clinical course, patients may manifest a variety of paraneoplastic syndromes, including erythrocytosis. However, there are few reports on the clinical and biochemical characteristics of HCC patients who manifest erythrocytosis. The purpose of this study is to evaluate the incidence of erythrocytosis in a large series of the Chinese patients with HCC, and to investigate the association of erythrocytosis with tumor volume and with serum levels of alpha-fetoprotein (AFP) and erythropoietin.

METHODS

Among 792 Chinese HCC patients who were seen during a 3-year period, we identified HCC patients with erythrocytosis as those with hemoglobin levels greater than 16.7 gm/dL (two standard deviations above the mean hemoglobin level of matched normal controls). The tumor size and serum levels of AFP and erythropoietin were evaluated in HCC patients with erythrocytosis to compare with HCC patients without erythrocytosis.

RESULTS

20 (2.5%) of 792 Chinese HCC patients presented with erythrocytosis. Nineteen of these 20 HCC patients were found to have either bi-lobar tumor involvement or a large tumor mass confined to one lobe of the liver. The estimated mean tumor volume of HCC patients with erythrocytosis was 50% of whole liver. When compared with HCC patients without erythrocytosis, the 20 HCC patients with high hemoglobin levels had significantly higher serum levels of AFP and erythropoietin (356,343 +/- 145,807 vs. 16,881 +/- 10,425 ng/mL, 135 +/- 45 vs. 25 +/- 4 mU/mL, respectively, p < 0.01).

CONCLUSIONS

Base on our findings, detection of erythrocytosis in a patient with HCC would indicate the presence of a large tumor burden, and high serum levels of both AFP and erythropoietin should be associated with this paraneoplastic syndrome.

Evidence for hepatitis C viral infection in patients with primary hepatocellular carcinoma

In testing for antibodies to the hepatitis C virus (anti-HCV) in 112 patients with primary hepatocellular carcinoma, 10 of 33 white patients (30%) and 15 of 79 Asian patients (19%) had a positive response to the antibody. The antibody profile to individual hepatitis C viral antigens and the presence of circulating hepatitis C viral RNA were determined in the 25 patients. The anti-HCV antibodies most frequently detected were toward the antigens from the core (C22) and NS3 regions. Serum hepatitis C viral RNA was present in 17 of the 25 patients (68%), and these patients tended to have serum levels of alanine and aspartate aminotransferases higher than those patients without viremia (136 +/- 22 U per liter versus 64 +/- 11 U per liter and 161 +/- 26 U per liter versus 79 +/- 14 U per liter, respectively, both P < .05). Of the 15 Asian patients with hepatocellular carcinoma and anti-HCV, 4 (27%) had coexisting hepatitis B surface antigen (HBsAg) and 13 (87%) had antibodies to either hepatitis B core or surface antigen. Of the 10 white patients with anti-HCV, however, only 1 (10%) had hepatitis B virus antibodies (P < .01). Among 4 Asian patients with coexisting anti-HCV and HBsAg, 1 was found to have serum hepatitis B viral DNA and the other 3 had hepatitis C viral RNA. A history of blood transfusion was obtained from 12 of the 25 patients with anti-HCV (48%); 20 (80%) had coexisting cirrhosis. Our findings support the hypothesis that hepatitis C virus is an important etiologic agent in the development of primary hepatocellular carcinoma in both white and Asian patients in the United States.

Hypercalcemia and parathyroid hormone-related protein in hepatocellular carcinoma

A two-site immunoradiometric assay (IRMA) of parathyroid hormone-related protein (PTHrP) was employed to react with circulating concentrations of PTHrP in 14 patients with hepatocellular carcinoma (HCC) and hypercalcemia (> 10.6 mg/dl). Eleven of them had unresectable lesions and three received transcatheter arterial chemo-embolization (TACE) treatment. Patients had no evidence of bony metastases and only one had evidence of a parathyroid lesion (by bone scan and serum parathyroid hormone level, respectively). The urinary cAMP level was increased in all patients, but the serum 1,25-dihydroxyvitamin D and plasma cAMP levels varied. Twelve patients had elevated alpha-fetoprotein (AFP) (> 400 ng/ml) and two of them had mildly elevated AFP levels (11 and 147 ng/ml). Their PTHrP concentrations were elevated (7.1 to 33.2 pmol/l), compared with normal levels obtained in our laboratory (< 3.5 pmol/l). A significant decrease in plasma PTHrP (from 27.4 to 5.2 pmol/l), serum calcium concentrations (from 16.3 to 9.4 mg/dl) and AFP levels (from 64,787 to 3129 ng/ml) was observed on the day following TACE treatment. These results, by using an improved technique, extend the findings that hypercalcemia in patients with HCC is associated with increased renal reabsorption of calcium and increased bone resorption of PTHrP generated by HCC.

Effects of manidipine hydrochloride on blood pressure in hypertensive patients--a comparison with nifedipine retard

Manidipine hydrochloride (MH) is a new calcium channel antagonist which is not yet available in Taiwan. Thus, a clinical trial was performed. The clinical effects and adverse effects of MH were compared with those of nifedipine hydrochloride retard monotherapies. Sixty-three out-patients with mild to moderate hypertension and no advanced systemic diseases were randomly divided into 2 groups. Twenty patients remained in each group after some patients withdrew from the study. Blood pressure decreased significantly after treatment in both groups (p < 0.01). In the manidipine group, systolic blood pressure (SBP) decreased from 164 +/- 14 to 140 +/- 18 mmHg and diastolic BP (DBP) decreased from 99 +/- 6 to 87 +/- 7 mmHg by the 8th week. In the nifedipine group, SBP decreased from 163 +/- 11 to 134 +/- 17 mmHg and DBP decreased from 101 +/- 10 to 88 +/- 9 mmHg by the 8th week. Pulse rates did not change significantly. Antihypertensive efficacy was 18/20 (90%) and 19/22 (86.4%) in the manidipine and nifedipine groups, respectively. There were a few adverse effects in both groups, the reaction was severe as to lead to the discontinuation of medication in two patients in the nifedipine group. No significant changes in laboratory tests were identified in either group, except for minimal decreases of lactate dehydrogenase and creatine kinase in the nifedipine group. We conclude that MH was equally safe and effective as nifedipine and it may have less severe side effects compared to nifedipine.

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.

Hepatic actinomycosis with portal vein thrombosis mimicking hepatocellular carcinoma: a case report

A fatal case of hepatic actinomycosis with portal vein thrombosis is reported. The diagnosis of actinomycosis was delayed because of its rarity in Taiwan. This 63-year-old man was admitted due to body weight loss and poor appetite. No fever was noted before admission. Liver biochemical test showed a decreased serum albumin level with elevated serum levels of globulin and alkaline phosphatase. He was not a hepatitis B carrier and his serum level of alfafetoprotein was within normal range. Image studies (abdominal sonography and computed tomography) showed a hepatic mass over the medial segment of the left lobe with involvement of right lobe of the liver. Main portal vein thrombosis was also seen. Because of profound cachexia, he died of aspiration pneumonia and disseminated intravascular coagulation on the 11th day after admission. An autopsy revealed hepatic actinomycosis. High index of suspicion for early diagnosis and treatment is emphasized.

Ursodeoxycholic acid in the treatment of primary biliary cirrhosis: a short-term, randomized, double-blind controlled, cross-over study with long-term follow up

In order to evaluate the efficacy of ursodeoxycholic acid (UDCA) in the treatment of Chinese patients with primary biliary cirrhosis, a short-term, randomized, double-blind controlled, cross-over study was done with long-term follow up. In the first part of the study, 12 patients were randomly chosen to receive either UDCA 600 mg/day for 3 months followed by a placebo for 3 months or a placebo for 3 months followed by UDCA for 3 months. The clinical symptoms of pruritus improved when the patients were receiving UDCA but became worse when receiving a placebo. Mean serum levels of alkaline phosphatase (ALPase), gamma-glutamyl transferase (gamma-GT), total bilirubin, cholesterol, alanine aminotransferase (ALT) and aspartate aminotransferase all decreased below the baseline values when receiving UDCA treatment and all increased above the baseline values when receiving the placebo. The difference was statistically significant. In the second part of the study, 19 patients received long-term UDCA treatment (mean 20 months). The clinical symptoms of pruritus improved in 90% of the pruritic patients. Serum levels of ALPase, gamma-GT and ALT fell significantly from the pretreatment values, 6, 12 and from the mean 20 months after UDCA treatment. Serum levels of total bilirubin fell significantly 6 and 12 months after UDCA treatment but did not reach statistical significance at the last follow up. No patient lost antimitochondrial antibody and elevated immunoglobulin levels did not improve significantly, but the Mayo clinical risk score improved significantly after long-term UDCA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Transport defects of rabbit inner medullary collecting duct cells in obstructive nephropathy

Urinary obstruction markedly reduces collecting duct Na+ reabsorption. To define the cellular mechanisms of this derangement in Na+ reabsorption in inner medullary collecting duct (IMCD) of obstructed kidneys, suspensions of intact IMCD cells and inner medulla plasma membranes (IMPM) were prepared from 24 h obstructed and untreated control kidneys. Oxygen consumption (QO2) studies revealed marked reductions in both amiloride-sensitive and ouabain-sensitive QO2 but not ouabain-insensitive QO2 in intact IMCD cells from obstructed, compared with control animals, indicating a reduction in oxygen-dependent transport activities of both the Na+ channel and the Na(+)-K(+)-adenosinetriphosphatase (ATPase). Amiloride-sensitive conductive 22Na+ uptake in intact IMCD cells from obstructed kidneys was significantly decreased by 45% at 10 s, 30 s, and 1-5 min (10 s: 2.42 +/- 0.63 vs. 4.49 +/- 0.64 nmol Na+ flux/mg protein, n = 7, P < 0.05; 1 min: 4.65 +/- 0.7 vs. 8.27 +/- 0.98 nmol Na+ flux/mg protein, n = 7, P < 0.05), indicating decreased activity of amiloride-sensitive Na+ channels in these cells. However, immunoblots of IMPM with antibodies to Na+ channel proteins did not show significant differences in content of Na+ channel proteins between membranes from obstructed and control groups. Ouabain-sensitive Na(+)-K(+)-ATPase activity in IMPM of obstructed kidneys was also reduced (61.1 +/- 18.1 vs. 152.6 +/- 25.8 nmol ATP degradation.min-1.mg protein-1, n = 6, P < 0.02), and immunoblots with monoclonal antibodies against the alpha 1- and beta-subunits of rabbit Na(+)-K(+)-ATPase showed a 51 +/- 7% reduction of both subunits in IMPM from obstructed kidneys (n = 4).(ABSTRACT TRUNCATED AT 250 WORDS)

Transport defects of rabbit medullary thick ascending limb cells in obstructive nephropathy

To characterize the sodium transport defect responsible for salt wasting in obstructive nephropathy, the major sodium transporters in the medullary thick ascending limb (mTAL), the apical Na-K-2Cl cotransporter and the basolateral Na-K-ATPase, were studied in fresh suspensions of mTAL cells and outer medulla plasma membranes prepared from obstructed and untreated kidneys. Oxygen consumption (QO2) studies in intact cells revealed marked reductions in the inhibitory effects of both furosemide and ouabain on QO2 in cells from obstructed, as compared with control animals, indicating a reduction in activities of both the Na-K-2Cl cotransporter and the Na-K-ATPase. Saturable [3H]bumetanide binding was reduced in membranes isolated from obstructed kidneys, but the Kd for [3H]bumetanide was unchanged, indicating a decrease in the number of functional luminal Na-K-2Cl cotransporters in obstructed mTAL. Ouabain sensitive Na-K-ATPase activity in plasma membranes was also reduced, and immunoblots using specific monoclonal antibodies directed against the alpha and beta subunits of rabbit Na-K-ATPase showed decreased amounts of both subunits in outer medullas of obstructed kidney. A significant decrease in [3H]bumetanide binding was detected after 4 h of ureteral obstruction, whereas Na-K-ATPase activity at this time was still not different from control. We conclude that ureteral obstruction reduces the amounts of both luminal Na-K-2Cl cotransporter and basolateral Na-K-ATPase in mTAL of obstructed kidney and that these reductions contribute to the salt wasting observed after release of obstruction.

A randomized controlled trial comparing octreotide and vasopressin in the control of acute esophageal variceal bleeding

This randomized controlled trial was conducted to compare the efficacy of intravenous infusion of octreotide (a synthetic long-acting somatostatin analogue) with vasopressin in 48 cirrhotic patients with endoscopically proven bleeding esophageal varices. Twenty-four patients received a continuous infusion of octreotide 25 micrograms/h for 24 h after an initial bolus of 100 micrograms and another 24 patients received a continuous infusion of vasopressin 0.4 U/min for 24 h. Bleeding was initially controlled after 6 h of drug infusion in 88% (21/24) and 54% (13/24) of the patients treated with octreotide and vasopressin respectively (p = 0.03). Complete control of bleeding after 24 h of drug infusion was achieved in 15 (63%) patients receiving octreotide and in 11 (46%) patients receiving vasopressin (p > 0.05). Side effects during drug infusion such as headache, chest pain and abdominal pain were significantly lower in the octreotide group (3/24) than in the vasopressin group (11/24). Serum gastrin and insulin levels fell significantly following octreotide infusion, but plasma glucose levels remained unchanged. Mortality related to bleeding esophageal varices was no different between the two groups. This report showed that octreotide infusion was more effective and had fewer side effects than vasopressin in initial controlling of acute esophageal variceal bleeding until an elective endoscopic sclerotherapy could be performed.

Current seroepidemiology of hepatitis D virus infection among hepatitis B surface antigen carriers of general and high-risk populations in Taiwan

In order to assess the current seroepidemiology of hepatitis D virus (HDV) infection in Taiwan where hepatitis B virus (HBV) is hyperendemic, a total of 756 voluntary blood donors, 641 prostitutes, 1,014 patients with sexually transmitted diseases (STDs), and 628 drug abusers were studied. Radioimmunoassays were used for testing HBV infection markers and antibody against HDV (anti-HDV) among HBsAg carriers. The anti-HDV prevalence among HBsAg carriers was significantly higher in STD patients (9.6%), prostitutes (33.1%), and drug abusers (68.1%) than in blood donors from the general population (2.2%). The prevalence gradually increased with age in blood donors and STD patients, but reached a plateau at a young age in prostitutes and drug abusers. Males had a higher prevalence than females in blood donors (2.7% vs. 0), STD patients (8.2% vs. 7.5%), and drug abusers (69.0% vs. 57.1%), but the difference was not statistically significant. STD patients with syphilis had a higher prevalence (19.5%) than those affected with non-ulcerating STDs (5.3%). While unlicensed prostitutes had a lower prevalence (13.6%) than licensed prostitutes (44.9%), intravenous drug abusers had a higher prevalence (73.1%) than non-intravenous drug abusers (34.6%). There was a twofold increase in anti-HDV prevalence from 1986 to 1989 among prostitutes, but the prevalence remained unchanged in the general population and drug abusers. HDV infection remains limited to the high-risk groups and spread mainly by promiscuity and needle sharing in Taiwan.

Hypercholesterolaemia in patients with hepatocellular carcinoma

Ninety-one (11.4%) subjects with hypercholesterolaemia (serum cholesterol level more than 250 mg/dL) of 792 Chinese patients with hepatocellular carcinoma (HCC) were studied in Taiwan. All 91 patients had large tumours greater than 7 cm in diameter and a tumour volume greater than 50%; 56 (61%) of these patients manifested tumour involvement in both lobes of the liver. The HCC patients with hypercholesterolaemia had significantly higher mean serum levels of albumin, triglyceride and alpha-fetoprotein (AFP) compared with age-sex-tumour volume matched HCC patients without hypercholesterolaemia. The associated incidence of hypoglycaemia in hypercholesterolaemic HCC patients was significantly higher than in HCC patients without hypercholesterolaemia (15/90 vs 4/90; P = 0.01). There was no significant difference in the survival analysis between HCC patients with and without hypercholesterolaemia. Eight and 11 of hypercholesterolaemic HCC patients had their tumours surgically resected and received transcatheter hepatic arterial chemoembolization (TAE), respectively. Serum cholesterol levels fell to the normal range after treatment and rose to abnormal levels again when tumours recurred after surgery or progressively enlarged after TAE. The change in pattern of serum cholesterol was parallel to the change in serum AFP. Serum cholesterol levels may serve as another marker in identifying tumour recurrence and the presence of a viable tumour mass in hypercholesterolaemic HCC patients who have received surgical resection or TAE.

Different sensory blockade of interscalene versus axillary approach of brachial plexus block

We examined results of brachial plexus block in 31 young male patients who underwent upper extremity surgical procedures. Interscalene block was performed using a paresthesia technique in 13 patients and axillary block, using the perivascular technique, in 18 patients. In both groups, 30 ml 1.5% lidocaine with 1:200,000 epinephrine was injected. Sensory blockade was evaluated at 5 min and 15 min after injection, determined by pinprick. Results showed that the interscalene technique preferentially blocked the cephalad nerves while the axillary technique produced similar block of both cephalad and caudal nerves of the brachial plexus. Difference between groups was statistically significant, suggesting that the extent of nerve block depends on the technique of approach per se. The difference in patterns of nerve blocked by either technique could be due to the access of local anesthetic to the different components of plexus in the sheath.

[Comparison of anesthetic morbidity and mortality before and after the implementation of quality assurance in Tri-Service General Hospital]

The desire to improve anesthetic outcome is a cornerstone in modern anesthesia. There are many means to reach this goal, such as enforcement in personal training, elevation of monitoring standards, constant vigilance and stern quality assurance (QA). The department of Anesthesiology, Tri-Service General Hospital, has adopted the QA program and implemented it since March 1, 1990. Because there were no significant differences in terms of personnel training, monitoring standards and types of anesthesia and surgery before and after the application of QA program, we investigated the effects of QA on anesthetic major morbidity and coma/mortality. We analyzed the anesthetic results obtained in two separate periods respectively spanning from Jan. 1, 1989 to Dec. 31, 1989 and from Mar. 1, 1990 to Feb. 28, 1991. During the first two months of 1990, the department's personnel were trained to be familiar with the QA program. We compared the anesthetic major morbidity and coma/mortality of one year before the implementation of QA with those in a one-year period after its implementation. Before and after enforcement of QA, there were no significant differences (p greater than 0.05) regarding major morbidity and coma/mortality, but the rates of anesthetic complications were lower after the practice of QA program. Since the functions of QA was aimed at alerting the anesthetic personnel to keep constant vigilance over the act of anesthesia, QA in theory could reduce anesthetic accidents and mishaps related jointly to surgery and anesthesia. The reason why QA did not decrease anesthetic major morbidity and coma/mortality in this study may be due to limited number of anesthesia in relatively short period.(ABSTRACT TRUNCATED AT 250 WORDS)

The prevalence of anti-hepatitis C virus among Chinese patients with hepatocellular carcinoma

To evaluate the role of hepatitis C virus (HCV) in Chinese patients with hepatocellular carcinoma (HCC), the antibodies to HCV (anti-HCV) were detected by enzyme immunoassay in 41 (12.6%) of the 326 patients with HCC. However, none of 35 patients with metastatic carcinoma of the liver had detectable anti-HCV. The prevalence of anti-HCV was significantly higher in patients with hepatitis B surface antigen (HBsAg)-negative HCC than those with HBsAg-positive HCC (37.3% versus 4.1%, P less than 0.0001). However, the prevalence of anti-HCV was much higher in patients with HCC with negative results for HBsAg and antibody to hepatitis B core antigen (54.5%). The mean age of patients with HCC with positive results for anti-HCV was significantly greater than that of patients with HBsAg-positive HCC (65.1 versus 55.5 years, P less than 0.0001). Alpha-fetoprotein levels greater than 20 ng/ml were found in 70.7% of patients with HCC with positive results for anti-HCV and in 73.3% of patients with HBsAg-positive HCC. Of the Chinese patients with HCC, 74.5% had HBsAg-positive results and 96.6% had positive results for antibody to hepatitis core antigen. These data indicate that, although HCV may play an etiologic role in HCC, hepatitis B virus is still the most important causal agent among most Chinese patients with HCC.

The prevalence of anti-hepatitis C virus among Chinese patients with hepatocellular carcinoma

To evaluate the role of hepatitis C virus (HCV) in Chinese patients with hepatocellular carcinoma (HCC), the antibodies to HCV (anti-HCV) were detected by enzyme immunoassay in 41 (12.6%) of the 326 patients with HCC. However, none of 35 patients with metastatic carcinoma of the liver had detectable anti-HCV. The prevalence of anti-HCV was significantly higher in patients with hepatitis B surface antigen (HBsAg)-negative HCC than those with HBsAg-positive HCC (37.3% versus 4.1%, P less than 0.0001). However, the prevalence of anti-HCV was much higher in patients with HCC with negative results for HBsAg and antibody to hepatitis B core antigen (54.5%). The mean age of patients with HCC with positive results for anti-HCV was significantly greater than that of patients with HBsAg-positive HCC (65.1 versus 55.5 years, P less than 0.0001). Alpha-fetoprotein levels greater than 20 ng/ml were found in 70.7% of patients with HCC with positive results for anti-HCV and in 73.3% of patients with HBsAg-positive HCC. Of the Chinese patients with HCC, 74.5% had HBsAg-positive results and 96.6% had positive results for antibody to hepatitis core antigen. These data indicate that, although HCV may play an etiologic role in HCC, hepatitis B virus is still the most important causal agent among most Chinese patients with HCC.

Comparisons of the effects of calcium carbonate and calcium acetate on zinc tolerance test in hemodialysis patients

Because aluminum hydroxide, as a phosphate binder, lowered intestinal zinc absorption, we studied the effects of calcium carbonate (CaCO3) and calcium acetate (CaAc), two other phosphate binders, on intestinal Zn absorption in nine patients on hemodialysis and in 11 controls by measuring 1- and 2-hour serum Zn levels after oral administration of 50 mg of elemental Zn as Zn gluconate with or without concomitant administration of 2 g CaCO3 (800 mg elemental Ca) or 3 g CaAc (750 mg elemental Ca). Fasting serum Zn levels were not different between patients and controls (14.0 +/- 2.3 v 14.1 +/- 1.2 mumol/L [91.8 +/- 14.9 v 92.3 +/- 8.0 micrograms/dL]), but the area under the curve of serum Zn increment (AUC) 2 hours after an oral Zn challenge without or with either of two of phosphate binders used was significantly smaller in patients than in controls (P less than 0.05). The AUC after concomitant administration of Zn with CaCO3 did not differ from that of Zn alone in either patients or controls, but it was significantly less in Zn with CaAc than in Zn alone or in Zn with CaCO3 in both groups. The results demonstrate that intestinal Zn absorption after an oral Zn challenge decreased in patients on hemodialysis and concomitant administration of CaAc, but CaCO3 did not decrease intestinal Zn absorption in either group.

Growth hormone heterogeneity in American plaice pituitaries: isolation, characterization, and partial amino acid sequence

Growth hormones (GHs) have been isolated from pituitary glands of American plaice (Hippoglossoides platessoides), a marine flatfish, using affinity and gel filtration chromatography, followed by preparative polyacrylamide gel electrophoresis (PAGE). A bioassay based on serum triiodothyronine elevation in immature rainbow trout was used to monitor biological activity. These GHs originate from two molecular mass regions, 42K and less than 33K relative molecular mass (Mr), in their native state. The 42K Mr region yielded two forms of GH, which differ in terms of quantity and net charge as evidenced by native PAGE, a major variant with a relative mobility of (Rf) 0.22 and a lesser variant with Rf 0.28. The less than 33 Mr region has a single GH species with Rf 0.22. Upon sodium dodecyl sulfate-PAGE, without reduction, both GH variants from the 42K Mr region gave Mrs of 21K, while the GH from the less than 33K Mr region was 20K Mr, typical of monomeric vertebrate GHs. The proteins composing the 42K Mr region are proposed as GH dimers since they yield 21K Mr peptides. The less than 33K Mr region contains a GH monomer (20K Mr) in its native state. An amino-terminal amino acid sequence, identical for both the 42K and the 20K Mr Rf 0.22 forms, has good homology with other complete fish GH sequences near their carboxyl-terminal regions (between amino acids 130 and 196). The GH dimers (42K Mr) predominate in the plaice pituitary, contributing 93% of the total, of which 86% gives rise to the Rf 0.22 variant.

Isolation of sockeye salmon growth hormone utilizing serum triiodothyronine enhancement in rainbow trout to monitor biological activity

Growth hormone (GH) was isolated from sockeye salmon (Oncorhynchus nerka) pituitary glands using established techniques of affinity and gel filtration chromatography, and preparative polyacrylamide gel electrophoresis. The GH activity was followed throughout the fractionation procedure with a bioassay based on the increase of serum triiodothyronine (T3) in rainbow trout (Oncorhynchus mykiss), measured by radioimmunoassay (RIA). Amino-terminal amino acid sequence analysis and subsequent comparison with established GH sequences from other Oncorhynchus sp. were used to confirm the isolation of sockeye salmon GH (ssGH). The bioassay was sensitive to a dose of 55 ng of purified ssGH/g fish. Monomeric GHs, located in the carbohydrate-poor protein fraction, were the only pituitary components that elevated serum T3. Twenty-four hours after GH injection was an appropriate and practical time to blood sample, allowing completion of the bioassay, including RIA, in 3 days. The generic homology, between the source of pituitaries and the bioassay animals used in this study, should permit the bioassay to be useful during GH isolation from pituitaries of all Oncorhynchus sp.

Hamartoma of spleen: a case report

Hamartoma of the spleen is a rare benign tumor. Only about 105 cases in English-writing literature were reported after first description by Rokitansky in 1861. We reported one case of asymptomatic splenic hamartoma in Taiwan which was found incidentally by ultrasonographic examination. Ultrasonography of abdomen revealed a slightly hypoechoic and nearly isoechoic tumor mass in the spleen. Computed tomography of the abdomen revealed a well-defined, low-attenuation mass in the spleen, which became isodense after contrast injection. Celiac arteriography and superselective splenic arteriography revealed a hypervascular mass with fine tumor vessels and tumor stains in the spleen. Splenectomy was performed and the microscopic examinations revealed typical red-pulp type hamartoma of the spleen.

[Studies on antiaggregating drugs of horseshoe crab amebocytes]

The effects of drugs on amebocyte spontaneous aggregation and endotoxin induced aggregation were studied. N-Ethylmaleimide, ethylenediamine tetraacetate, propranolol, verapamil and lidocaine but not dibutyryl cyclic AMP could reduce the aggregating rate of amebocytes. The speed of degranulation induced by endotoxin was reduced by N-ethylmaleimide, ethylenediamine tetraacetate, propranolol, verapamil and caffeine. These results suggest that Ca+2 and c-AMP may play an important role in amebocyte spontaneous aggregation and endotoxin induced aggregation. The blocking agent of Ca+2 and c-AMP can also antagonize the aggregation of amebocytes.

Antibodies to hepatitis C virus in prospectively followed patients with posttransfusion hepatitis

In an attempt to investigate the incidence and clinical course of type C viral hepatitis among patients with posttransfusion hepatitis, antibodies to hepatitis C virus (anti-HCV) in sera were measured from 42 prospectively followed cardiovascular surgery patients who developed hepatitis after blood transfusions. Of these, 35 (83.3%) had anti-HCV seroconversion during a 6- to 12-month follow-up period. The mean interval between blood transfusion and onset of active anti-HCV seroconversion was approximately 3 months after the first elevation of serum alanine aminotransferase levels (18.1 vs. 6.4 weeks). There was no correlation between fluctuations in serum alanine aminotransferase levels and anti-HCV titers. Of 26 patients with type C posttransfusion hepatitis who were followed greater than 1 year, 20 (76.9%) continued to have abnormal serum alanine aminotransferase levels. The results indicate that HCV is the major agent of posttransfusion hepatitis in Taiwan. Furthermore, it plays an important role in chronic hepatitis among transfused patients.

A prospective study of post-transfusion non-A, non-B (type C) hepatitis following cardiovascular surgery in Taiwan

In an attempt to investigate the incidence and clinical course of non-A, non-B (NANB) hepatitis following blood transfusion in Taiwan, 288 patients who underwent cardiovascular surgery and received blood transfusion were followed prospectively with serum liver aminotransferase levels and viral hepatitis markers for at least six months. None had any past history of liver disease or drug abuse. All blood donors were tested for serum hepatitis B surface antigen and alanine aminotransferase (ALT) (greater than 45 U/L). Thirty-seven (12.8%) patients developed PTH. 34 (91.9%) were considered to be cases of NANB hepatitis, 2 (5.4%) were cytomegalovirus hepatitis, and one (2.7%) was caused by Epstein-Barr virus. No one developed hepatitis B post-transfusion hepatitis (PTH). Of the 34 NANB PTH patients, 15 (44.1%) were asymptomatic, 16 (47.1%) had clinical symptoms, and 9 (26.5%) had serum total bilirubin levels higher than 2 mg/dl. There was no case of fulminant hepatic failure. Of 26 NANB PTH patients who were followed up for more than one year, 15 (57.7%) still had abnormal serum ALT levels. The incubation period of NANB PTH ranged from 2 to 16 (mean 6.1 +/- 3.2) weeks. Of the 37 PTH patients, 32 (86.5%) were found to have anti-HCV seroconversion during one year follow-up period. NANB PTH is as common in Taiwan as in the United States and Japan, and is demonstrated by this study to be due mostly to HCV.

Plasma atrial natriuretic peptide and natriuretic response to water immersion in patients with nephrotic syndrome

Eight nonnatriuretic (daily Na excretion less than 50 mEq), 4 natriuretic (daily Na excretion greater than 50 mEq), and 4 steroid-responsive nephrotic patients, and 12 normal controls were studied with a 4-hour water immersion with measurements of electrolytes, plasma atrial natriuretic peptide (ANP), plasma renin activity (PRA), and plasma aldosterone (PA) [corrected]. Four nonnatriuretic patients further received 25 g albumin infusion, with a subsequent 2-hour water immersion study. The results are as follows: (1) In the nonnatriuretic patients, the extremely low basal Na excretion rate, high PRA, and PA levels indicated a state of active Na retention. In spite of the water-immersion induced suppression of PRA and PA and a comparable magnitude of plasma ANP increment, the natriuretic response to water immersion was blunted in the nonnatriuretic patients. (2) In the natriuretic patients, water immersion resulted in a similar magnitude of natriuresis but a higher degree of plasma ANP increment in comparison to the normal controls. (3) Natriuretic and plasma ANP responses to water immersion were not different between the steroid-responsive patients and normal controls. (4) The increase in plasma ANP and the suppression of PRA and PA after 25 g albumin infusion did not result in natriuresis until the further suppression of PRA and PA and the further stimulation of plasma ANP by subsequent water immersion. The above results indicate that the natriuretic and plasma ANP responses to water immersion are related to the basal Na status in nephrotic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Superinfection with hepatitis C virus in patients with symptomatic chronic hepatitis B

11/323 patients (3.4%) with symptomatic chronic hepatitis B were positive for antibody to hepatitis C virus (anti-HCV). The positive rate of anti-HCV in patients with serum alanine aminotransferase (ALT) levels greater than 200 U/l (n = 219) did not exceed that of the patients with ALT less than or equal to 200 U/l (n = 104) (2.7% vs. 4.8%). Of the 219 patients who were positive for hepatitis B e antigen (HBeAg) and/or hepatitis B virus-DNA (HBV-DNA), 5 (2.3%) had anti-HCV, while 6/104 patients (5.8%) who were positive for antibody to HBeAg (anti-HBe) had anti-HCV (p greater than 0.1). In contrast to the anti-HCV-negative patients, the patients with anti-HCV had a higher percentage of cirrhosis in their liver histological findings (36.4% vs 5.4%, p less than 0.005). In conclusion, the prevalence of HCV superinfection in symptomatic chronic hepatitis B patients is low and HCV superinfection is not an important factor in acute exacerbation of chronic hepatitis B. However, the superinfection with HCV may exacerbate the existing liver disease and accelerate its progression.

Study of plasma neuropeptide Y (NPY) and catecholamines levels during isoflurane anesthesia

Twelve ASA physical status I-II patients were studied after obtaining institutional approval and informed contents. All patients were free from endocrine and metabolic disease undergoing elective low risk operation. Pethidine 1 mg/kg i.m. and benzodiazepine 0.01 mg/kg p.o. were given as premedication one hour before anesthesia. Anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1.5 mg/kg for tracheal intubation. Anesthesia was maintained with 2% isoflurane and 50% N2O in oxygen. Ventilation was controlled and adjusted to maintain an end-tidal CO2 concentration of 25-35 torr. Atracurium 0.4 mg/kg was given as muscle relaxant. Blood samples were obtained from radial arterial catheter, 15 minutes before induction of anesthesia and 5 min after anesthesia, 15 min, 30 min, 60 min during operation and 30 min after operation in postanesthesia recovery room. The results showed that there were no statistically significant changes in plasma levels of NPY and catecholamines during operation underwent isoflurane anesthetic technique. This result indicates that isoflurane anesthesia can block the plasma NPY as well as catecholamines during surgical stress.

Plasma atrial natriuretic peptide in patients with chronic renal failure

Plasma atrial natriuretic peptide (ANP) levels were measured in non-dialyzed and dialyzed chronic renal failure (CRF) patients and in normal subjects. Changes in plasma ANP in response to hemodialysis (HD) and to isolated ultrafiltration (UF) were also investigated in dialyzed CRF patients. Plasma ANP levels were significantly higher in 28 non-dialyzed CRF patients than in 27 normal subjects (mean +/- SEM, 174.0 +/- 25.9 vs 25.0 +/- 1.9 pg/ml, p less than 0.001). Plasma ANP levels did not correlate with blood urea nitrogen or serum creatinine, however patients with advanced renal failure (creatinine clearance less than 10 ml/min) with cardiomegaly (cardiothoracic ratio greater than 50%) or hypertension (BP greater than 140/90 mmHg) had significantly higher plasma ANP levels than those who were not. A 6-hour HD significantly decreased the plasma ANP level (423.4 +/- 71.3 to 220.6 +/- 40.0 pg/ml, p less than 0.001) and body weight in 21 dialyzed CRF patients, and the decrement in plasma ANP showed a positive correlation with the decrement in body weight (r = 0.425, p = 0.056). In 8 dialyzed CRF patients, we further performed a 1-hour isolated UF for removal of isoosmotic intravascular fluid without changes in the solute concentrations, followed by a subsequent 5-hour HD. The decrease in plasma ANP during the 1-hour UF period was 68% of the total ANP decrement for the whole 6-hour study. The average plasma ANP level was decreased with 94.6 +/- 42.5 pg/ml/kg/h in the UF period compared to 3.5 +/- 1.4 pg/ml/kg/h in the HD period (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Metastatic malignant melanoma of upper gastrointestinal tract

A 74-year-old male patient developed intermittent melena and anemia after he had received surgical resection for malignant melanoma of the right foot and radical dissection of the right inguinal metastatic lymph node. The source of bleeding was identified to be metastatic melanoma of stomach and duodenum by panendoscopy and biopsy. Patient refused surgical intervention and died of pneumonia two weeks later.

Clinical study of syncope during acupuncture treatment

From August 1988 to April 1989, we observed 52 patients who developed so-called 'needle fainting' (or what the Chinese call 'Yun-Cheng' phenomenon) 55 times among a total sample of 28,285 procedures of acupuncture therapy at the Center for Traditional Medicine of Veterans General Hospital in Taipei. Of these syncopal patients, 35 were male and 17 were female. Their mean age was 45 years (with a range of 11 to 72 years). All patients were in an upright position when needle fainting occurred. Their usual manifestations were pallor, cold sweating, nausea, and bradycardia. They all recovered soon after lying down; no one developed a complete loss of consciousness. No mortality was noted. When comparing the patients who experienced syncope during their first visit to our Clinic (Group I, n = 27) with the patients who experienced syncope in a follow-up treatment (Group II, n = 25; 3 patients had 2 episodes in sequential treatments), we found a significantly higher incidence of needle fainting (p less than 0.0001) in Group I patients (27 out of 2,855 or 0.94%) than in Group II patients (28 out of 25,430 or 0.11%). The mean age of Group I patients (39 +/- 15.4 years) was significantly less than that of Group II patients (51.6 +/- 18.0 years) (p less than 0.001). The coexistence of other medical problems was significantly higher in Group II patients (72%) than in Group I patients (18.5%) (p less than 0.0001).

Human leukocyte antigen (HLA) frequency among patients with nasopharyngeal carcinoma in Taiwan

In order to assess the association between human leukocyte antigens (HLA) and nasopharyngeal carcinoma (NPC), a total of 10 familial and 10 sporadic NPC patients and 171 unrelated healthy controls were studied. HLA typing was performed using commercial trays which defined 30 specificities of HLA-A, B and C loci and 10 specificities of HLA-D locus according to the method of Tiwari and Terasaki. HLA-A2, B16 and DR1 were found to be higher among patients with NPC than unrelated healthy controls with an odds ratio (OR) and a 95% confidence interval of 5.91 (2.1-16.6), 6.00 (2.0-18.0) and 6.89 (1.3-37.5), respectively. Further analysis showed that A2(+) B16(+) haplotype was significantly associated with a much higher risk of NPC (OR = 15.5) as compared with A2(-) B16(-) haplotype. No difference in frequency distributions of HLA-A, B, C and D antigens was observed between familial and sporadic NPC patients.

Regulation of antifreeze protein production in winter flounder: a unique function for growth hormone

Salmon pituitary extract and the protein fraction unabsorbed on concanavalin A-Sepharose, the carbohydrate-poor fraction, depressed plasma levels of antifreeze proteins (AFP) when the pituitary fractions were administered to flounder in late fall or winter. The active pituitary protein occurred in the fraction with a mean molecular weight of 25,000. The two major isohormones of growth hormone (GH) were the only biologically active proteins identified from the pituitary. Hypophysectomized flounder synthesize AFP in the spring and the two isohormones of GH suppress the synthesis. The fraction of flounder pituitaries containing putative GH depressed flounder plasma levels of AFP in late fall.

[The role of ADP-cyclic AMP system in horseshoe crab amebocytes aggregation and gel formation]

A study of the effects of ADP and cyclic AMP related drugs on gel formation induced by endotoxin and amebocytes aggregation was conducted. The gel formation induced by endotoxin could be inhibited by ADP, cyclic AMP, ATP and aminophylline. Conversely, Phosphodiesterase enhanced gelation rate. A calmodulin antagonist, trifluoperazine, also inhibited endotoxin-induced gel formation, but this agent was able to induce potentiation in amebocytes aggregation. These results suggest that the cyclic AMP phosphodiesterase system may play an important role in endotoxin-induced gel formation, and it was concluded that, in the presence of both Ca++ and endotoxin, the calmodulin-like protein will activate the cyclic AMP phosphodiesterase system and decrease the concentration of cyclic AMP, thus promoting gel formation.

Isolation of an ammonium or methylammonium ion transport mutant of Escherichia coli and complementation by the cloned gene

During nitrogen-limited growth, Escherichia coli expresses a specific ammonium or methylammonium ion transport system (Amt). Strains carrying defects in Amt have been isolated following Tn10 transposon mutagenesis. These mutants have less than 10% of the transport activity of the parental strain. Glutamate, glutamine, arginine, or high levels (20 mM) of ammonium will serve as the sole nitrogen source for growth of these strains, and glutamine synthetase is normally expressed and repressed by the nitrogen regulatory (Ntr) system. When transformed with plasmid pGln84, containing lacZ fused to an Ntr promoter (glnLp), the Amt mutants expressed a normal level of beta-galactosidase. Furthermore, P1 bacteriophage transduction of the amt mutation into an Ntr mutant, normally constitutive for Amt, gave Amt- transductants. Therefore, the mutations are unlikely to lie within genes affecting Ntr elements. Following transformation with plasmid libraries of E. coli genomic DNA constructed in pUC9, two plasmids conferring the Amt+ phenotype on the amt mutants were isolated. These plasmids were unable to complement the Amt- phenotype of Ntr- mutants. Restriction digestion of these plasmids revealed common fragments, and Southern blot analyses indicated that the Amt-complementing sequence and the site of Tn10 insertion in the genome occur in the same 3.4-kilobase HindIII-SalI fragment. Insertion of TnphoA into this fragment produced amt::phoA fusions which gave high levels of alkaline phosphatase under nitrogen-limiting conditions but low levels during ammonia excess. This suggests that the amt product contains domains which are exported to the periplasm.

Seroepidemiological studies on hepatitis B and D viruses infection among five ethnic groups in southern Taiwan

In order to compare the prevalence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infection among five ethnic groups in Pingtung County of southern Taiwan, a total of 240 serum samples were collected from September to October, 1985, from the following five ethnic groups: Taiwanese, Hakka, Mainland Chinese, aboriginal Paiwanese, and aboriginal Rukaiese. Ages of subjects ranged from 5 to 69 years. All sera were tested for hepatitis B surface antigen (HBsAg), surface antibody (anti-HBs), and core antibody (anti-HBc) by radioimmunoassay (RIA). Hepatitis B e antigen (HBeAg) and antibody to hepatitis D antigen (anti-HDV) were also tested for those with HBsAg-positive sera. Results showed that 44.1% of all sera examined were negative for HBsAG but positive for both anti-HBs and anti-HBc; additionally, 24.6% were negative for both HBsAg and anti-HBs but positive for anti-HBc. Only 134 serum samples showed negative results for HBV markers, indicating an HBV infection rate of 88.8%. The anti-HDV positive rate was estimated to be 2.7% among HBsAg-positive subjects. The HBsAg-positive rates among Rukaiese, Paiwanese, Hakka, Taiwanese, and Mainland Chinese were 25.8, 22.5, 16.7, 12.9, and 10.0%, respectively; while the prevalence rates of HBV infection among the above five groups were 94.2, 94.6, 85.4, 87.5, and 82.5%, respectively. Differences in the HBsAg-positive rate and HBV infection rate among these ethnic groups were statistically significant. We conclude that people living in Pingtung County are more frequently infected with HBV when compared with inhabitants in northern Taiwan.

Yeast ARS function and nuclear matrix association coincide in a short sequence from the human HPRT locus

A sequence that supports extrachromosomal replication of plasmids in yeast has been identified within the first intron of the human hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene. This represents the first isolation of such an autonomously replicating sequence (ARS) from an exactly known position in the human genome. This ARS shares similarities of imparted yeast phenotype and DNA sequence with other heterologous ARSs. In addition, this sequence is found to be a matrix association region (MAR) on the basis of specific binding to nuclear matrices prepared from several mammalian cell types. It also exhibits anomalous electrophoretic behavior, characteristic of bent DNA, on polyacrylamide gels. The coincidence of these properties supports the possibility that this region may play a role in DNA replication within its normal chromosomal context.

Molecular cloning and expression of salmon prolactin cDNA

Prolactin was purified from chum salmon pituitaries. It was resolved into two variants by reverse-phase high-performance liquid chromatography. A cDNA library was prepared from Pacific chinook salmon pituitaries. Salmon prolactin gene was screened using a synthetic oligonucleotide based on partial protein sequence. A positive clone (PRL-10) was identified and sequenced. It is a full-size clone containing 1.1 kb and coding for a preprolactin of 211 amino acids. A modified prolactin plasmid (PRL-10A), in which the 5' untranslated sequence and the nucleotide sequence coding for the signal peptide of prolactin were deleted, was reconstructed into an expression vector using the heat-inducible lambda pL promotor. Mature prolactin, a single polypeptide of 22 kDa, was efficiently expressed in the bacteria at an elevated temperature.