Hepatitis B virus markers in Chinese twins

Chinese same-sex twins were recruited in order to study the distribution of different markers of hepatitis B virus (HBV) infection, including HBV surface antigen (HBsAg), antibody to HBV core antigen (anti-HBc), antibody to HBsAg (anti-HBs), HBV e antigen (HBeAg) and antibody to HBeAg (Anti-HBe), as well as to compare the concordance of these markers in pair-wise fashion among monozygotic (MZ) and dizygotic (DZ) twins and singleton controls. A total of 289 pairs of MZ twins, 102 pairs of DZ twins and 375 pairs of age-sex-matched singleton controls were studied. More than 50 percent of the members of each group (64.71% of MZ twins, 51.96% of DZ twins and 62.13% of controls) were found to be infected with HBV. In general, the patterns of the response to HBV infection in the 3 groups were similarly distributed. 20.17% of the members of the 3 groups (21.45% of MZ twins, 14.22% of DZ twins, and 20.80% of controls) were HBsAg carriers. Among the HBsAg carriers, 49.19% (44.35% of MZ twins, 34.48% of DZ twins and 55.77% of controls) were HBeAg carriers. No significant difference in the concordance of HBV infection was observed in the MZ and DZ twins. However, highly significant differences were noted between MZ twins and controls, and between DZ twins and controls. Highly significant differences were also observed in the concordance of carrier status between MZ and DZ twins and between MZ twins and controls, but not between DZ and controls. As for the other HBV markers, no significant differences were observed. It is concluded that the genetic influence in response to HBV infection markers is not well-characterized and requires further study.

Adult Hirschsprung's disease

This report presents a series of 17 patients with adult Hirschsprung's disease treated at the National Taiwan University Hospital and its affiliated hospitals from 1965 to 1988. Adults with Hirschsprung's disease may present with symptoms and operative findings different from those of children with Hirschsprung's disease. The symptoms, signs, criteria for diagnosis, operative findings, and operative procedures are presented.

Antibody to Epstein-Barr virus-specific DNase as a marker for field survey of patients with nasopharyngeal carcinoma in Taiwan

A serological survey using antibody to Epstein-Barr virus (EBV)-specific DNase activity as a marker for the identification of patients with nasopharyngeal carcinoma (NPC) has been carried out on healthy subjects who visited Government Employees' Clinic Center (GECC) for routine health examination and on individuals residing in NPC high-risk areas (HRA) in Taiwan. During a 3-year prospective study, 22,596 and 9,869 sera were collected from the GECC and HRA groups, respectively. Taking neutralization of 2 or more units of EBV DNase activity as a positive response, the positivity rates in the GECC and HRA groups were 5.4% and 11.92%, respectively. Among the antibody-positive individuals, three cases of NPC were found in the GECC group (detection rate 0.63%) and 11 in the HRA group (detection rate 1.32%). A further patient at stage III of the disease was found in the first year of following up of 1,005 antibody-positive individuals. Among the 12 NPC patients in the HRA, five were newly diagnosed as having stage II (three patients) and stage III (two patients) NPC. These results support the hypothesis that antibody against EBV-specific DNase activity may be a useful marker for detection of patients with NPC, and they imply that individuals having high levels of antibody to EBV DNase activity may have an increased risk of development of NPC.

Community-wide epidemiological investigation of a typhoid outbreak in a rural township in Taiwan, Republic of China

An outbreak of typhoid fever occurred in Chu-Tung township, Taiwan, with dates of onset from 6 July to 8 August, 1983. Fifty-four cases were hospitalized, of which 52 were laboratory confirmed. A chloramphenicol-resistant strain of Salmonella typhi was isolated from patients' blood samples. A community survey of 2772 people selected from 490 households by stratified systematic cluster sampling, presented an attack rate of 9.4 per 1000 and a case reporting rate of 10%. The attack rate was higher in males than females for persons younger than ten years, but was greater in females than in males aged 40 years and older. The only consistent characteristic of the early outbreak cases was drinking of tapwater (10/10, 100% versus 319/490, 65% of the controls). None of the early cases but 36% (13/36) of the late cases had drunk stream or river water. Households of early cases had better hygienic conditions than those of late cases. Laboratory examination of environmental specimens indicated Escherichia coli contamination of tapwater, well water and all stream foci associated with human activities. The epidemiological data combined with laboratory results suggested that the epidemic might be due to repeated contamination of some common source (such as municipal tapwater) and/or a variety of other vehicles.

Divalent cations suppress 3',5'-adenosine monophosphate accumulation by stimulating a pertussis toxin-sensitive guanine nucleotide-binding protein in cultured bovine parathyroid cells

We used pertussis toxin to study the mechanism(s) by which divalent cations lower cellular cAMP content in bovine parathyroid cells. In cultured parathyroid cells, high extracellular Ca2+ (5 mM) or Mg2+ (5-10 mM) lowers dopamine-stimulated cAMP content by 70-90%. Pertussis toxin (0.5 microgram/ml) totally blocks the inhibitory effects of Ca2+ and Mg2+ on cAMP content. Ba2+ and Sr2+ (5 mM) also lower cAMP content by 80-90%, and this effect is, likewise, blocked by pertussis toxin. Pretreatment with pertussis toxin had no effect on the release of cAMP into the extracellular fluid. The toxin also did not modify phosphodiesterase activity in sonicates of parathyroid cells (42.68 +/- 3.26 vs. 47.00 +/- 2.82 pmol cAMP hydrolyzed/10(6) cells.20 min in control and toxin-treated cells, respectively). Moreover, addition of the phosphodiesterase inhibitor isobutyl-methylxanthine did not modify the inhibition of dopamine-stimulated cAMP accumulation by 5 mM Ca2+ in control cells (85% vs. 86% inhibition, respectively, with and without isobutylmethylxanthine). Pertussis toxin-catalyzed ADP ribosylation in homogenates of control cells demonstrated the presence of two substrates with mol wt of 40K and 41K. Preexposure of cells to pertussis toxin overnight resulted in the complete loss of both substrates on subsequent ADP ribosylation with [32P]NAD. Pertussis toxin pretreatment did not enhance adenylate cyclase activity indirectly via reducing the extracellular Ca2+-induced rise in cytosolic Ca2+, since the cytosolic Ca2+ level at 5 mM Ca2+ was about 60% higher in pertussis toxin-treated than in control cells (531 +/- 85 vs. 326 +/- 35 nM; P less than 0.05). In addition, ionomycin had no significant effect on cellular cAMP levels in control cells despite increasing the cytosolic Ca2+ concentration to levels as high as 1700 nM at 10(-5) M. Thus, changes in cytosolic Ca2+ phosphodiesterase activity, or efflux of cAMP from the cell cannot explain the inhibition of cAMP accumulation by divalent cations or the reversal of this effect by pertussis toxin. Instead, the present data suggest that extracellular divalent cations modulate the formation of cellular cAMP in parathyroid cells by a process involving a pertussis toxin-sensitive guanine nucleotide regulatory protein, presumably inhibition of adenylate cyclase by Gi via a receptor-like mechanism.

Activities of uterine muscles from rats in late pregnancy

Although it has been reported that, in the uterine wall of rats at term, gap junctions between fibers of the same muscle layer are responsible for synchronized strong contractions, much less attention has been paid to the interaction between muscle layers. To learn about the relationship between the two uterine muscles of rats in late pregnancy, we developed a technique to do simultaneous monitoring of activities in two muscle layers. Using rectangular muscle strips, the electrical activity in one layer was measured with an intracellular microelectrode while the mechanical activity of the other layer was recorded through a force transducer. In some of the uterine wall strips prepared from animals on gestation day 15 and 16, interaction between longitudinal and circular muscle layers was observed. However, well coordinated activities of these two muscles did not occur until the morning of gestation day 21 and continued toward delivery. Usually, coordination presented as paired contractions, one in the circular muscle and the other in the longitudinal muscle. While these pairs of contractions appeared regularly, they also kept similar intervals. Sometimes, coordination presented as a continuous appearance of groups of three contractions, one in one layer and two in the other. Coordinating contractions of uterine muscles is considered to be beneficiary to the propelling of fetuses toward the cervix during parturition.

Meckel's diverticulum and related umbilical abnormalities: review of 26 cases

Twenty-six surgically documented cases of Meckel's diverticulum and related abnormalities at the National Taiwan University Hospital during a 7-year period (1980 through 1987) are reviewed. According to clinical presentation, they were classified into five groups: (1) hemorrhage in 10 cases, (2) inflammation in 4 cases, (3) intestinal obstruction in 4 cases, (4) umbilical abnormalities in 6 cases, and (5) incidental finding on laparotomy in 2 cases. The percentage of umbilical abnormalities was 23%. In contrast, the 2 cases found incidentally represented 8% of 26 cases in this series. The diagnosis of umbilical abnormalities is obvious. For cases with Meckel's diverticuli, however, we detected their complications (hemorrhage, inflammation and intestinal obstruction) only preoperatively except for the hemorrhagic group in whom 6 among 10 cases were proved to have ectopic gastric mucosa by Meckel's scan. Other aspects about the clinical presentation, method of diagnosis, strategy for management are reviewed and discussed.

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.

A case-control study of primary hepatocellular carcinoma in Taiwan

A case-control study was carried out to explore possible risk factors of primary hepatocellular carcinoma (PHC) in Taiwan. One hundred thirty-one PHC patients and 207 hospital control patients were interviewed and blood samples were collected for blood type and hepatitis B virus (HBV) infection marker tests. Eighty-three percent of the PHC patients were found to be hepatitis B surface antigen (HBsAg) positive as compared with 21.0% of the control patients with an odds ratio (OR) of 21.5. Hepatitis B e antigen (HBeAg) positive status increased the risk of PHC. No significant association was observed between erythrocyte genetic markers and PHC, except c of the Rh system, which was significantly lower in the PHC cases. As compared with the control patients, the PHC patients had a higher proportion with a history of liver diseases and more siblings affected with liver diseases. However, the variables such as cigarette smoking, alcohol drinking, peanut consumption, frequent intake of raw fish, heart diseases, peptic ulcer, malaria, hypertension, diabetes, color blindness, G-6-PD deficiency, surgical operation, blood transfusion, and liver diseases of parents and children were not found to be associated with PHC.

Comparison of the activity of circular and longitudinal myometrium from pregnant rats: co-ordination between muscle layers

1. Contractions and electrical activity were recorded from isolated segments of longitudinal (L) and circular (C) myometrium from rats on gestation days 16-17 and 21 before and during parturition. 2. The segments were arranged so that the activity of the two layers could be monitored simultaneously and independently. 3. Out of the 15 preparations from days 16-17, 13 showed no co-ordination of activity between the layers. In the other two preparations a large contraction of C occasionally initiated a contraction of L. Surgical separation of the layers disrupted the co-ordination and L then developed its independent rhythm. 4. On day 21 before delivery, eight of 10 preparations exhibited 1:1 co-ordination of activity between the two layers, but C did not consistently pace L. The pacing shifted from one layer to the other several times during an experiment. 5. During parturition there was a 1:1 co-ordination of activity in all 10 preparations examined. In nine of these L initiated the activity of the C. Surgical separation of the layers disrupted the co-ordination and C developed its independent rhythm. In one the pacing shifted from one layer to the other several times during the experiment. 6. In all cases where co-ordination between the layers was observed it was myogenic and apparently related to the spread of action potentials between the two muscles.

Atherogenicity and carcinogenicity of high-arsenic artesian well water. Multiple risk factors and related malignant neoplasms of blackfoot disease

The objective of this study was to examine multiple risk factors and correlated malignant neoplasms of blackfoot disease (BFD), a unique peripheral vascular disease related to continuous exposure to high-arsenic artesian well water. A total of 241 BFD cases, including 169 with spontaneous or surgical amputations of affected extremities, and 759 age-sex-residence-matched healthy community controls were studied to explore the risk factors of BFD. Multiple logistic regression analysis showed that artesian well water consumption, arsenic poisoning, familial history of BFD, and undernourishment were significantly associated with the development of BFD. The life-table method used to analyze cancer mortality of 789 BFD patients followed for 15 years showed a significantly higher mortality from cardiovascular diseases, peripheral vascular diseases, and cancers of bladder, skin, lung, and liver among BFD patients as compared with the general population in Taiwan or residents in the BFD-endemic area. The results imply the atherogenicity and carcinogenicity of the artesian well water in the BFD-endemic area.

Seroepidemiology of human T-cell lymphotropic virus type I infection in Taiwan

The epidemiological characteristics of human T-cell lymphotropic virus type I infection in Taiwan have been explored by an island-wide community-based survey, which was carried out among residents in 19 townships and metropolitan precincts randomly selected through stratified sampling. Serum specimens of 7278 healthy subjects were screened by enzyme-linked immunosorbent assay and confirmed by Western blot method. A total of 103 subjects showed positive or weak reactions by enzyme-linked immunosorbent assay, but only 35 of them were confirmed to be positive by Western blot analysis. The anti-human T-cell lymphotropic virus type I antibody positive rate was 4.81/1000. The seropositive rate increased with age in both males and females, and females had a greater seropositive rate than males for all the age groups. Aborigines and Hakka Taiwanese had higher seropositive rates than Fukien Taiwanese and Mainland Chinese. Those people with lower educational levels were found to be associated with higher anti-human T-cell lymphotropic virus type I seropositive rates.

Dopamine D1 receptors of the calf parathyroid gland: identification and characterization

The dopamine D1 receptor was identified in the calf parathyroid gland. The binding of the selective D1 receptor antagonist [3H]SCH-23390 to membranes of calf parathyroid was specific, reversible, and saturable with a dissociation constant of approximately 200 pM and a receptor density of 30 fmol/mg of protein. Dopaminergic agonists and antagonists inhibited [3H]SCH-23390 binding in a concentration-dependent and stereoselective manner with an appropriate pharmacological specificity for D1 dopamine receptors. Moreover, potent dopaminergic agonists recognized two affinity forms of the receptor, one displaying high affinity for agonists, termed D1 High, and one with low affinity, D1 Low. The addition of the nonhydrolyzable guanine nucleotide guanyl 5'-yl-imidodiphosphate caused the complete transition of the agonist high affinity form (D1 High) of the receptor to one displaying only low affinity for agonists (D1 Low). Sodium ions, however, caused a approximately 5-fold decrease in the affinity of agonists at both D1 High and D1 Low. Virtually identical results were obtained on D1 receptor preparations of neural origin. The D1 receptor identified here appears to be the one responsible for the physiological effects on the parathyroid gland, because dopamine-stimulated cAMP accumulation is stereoselectively blocked by the D1 receptor antagonist SCH-23390 in dispersed cells of the parathyroid gland. Moreover, a series of nine dopaminergic antagonists and agonists shows an excellent correlation between their potency in [3H]SCH-23390 binding assays and their corresponding effects on cAMP accumulation. In the case of agonists, Ka for activation of cAMP accumulation agrees most closely with the agonist low affinity site in binding experiments. Specific [3H]spiperone binding to D2 dopamine receptors was not detected in this tissue and as such, the calf-parathyroid gland provides a model system in which to study the molecular characteristics of dopamine D1 receptor-mediated events.

Effects of fluoride on parathyroid hormone secretion and intracellular second messengers in bovine parathyroid cells

Fluoride ion (F-) alone or in conjunction with aluminum (Al3+) has been shown to stimulate the activity of guanine nucleotide-binding proteins (G proteins) in cell membrane preparations from a variety of cell types and in intact hepatic cells. Several studies have indicated that G proteins are involved in the regulation of parathyroid hormone (PTH) secretion. Intracellular second messengers which modulate PTH secretion (e.g., cAMP) have also been found to be regulated by G proteins. We have, therefore, employed F- as a probe to investigate the possible role of G proteins in the modulation of PTH release and the intracellular second messengers that have been implicated in the control of PTH secretion. F- produces a dose-dependent inhibition of PTH release with a maximal inhibitory effect (67%) at 5 mM. F- exerts its inhibitory effect within 5 min and the degree of suppression of PTH secretion gradually increases over 1 hr. F- (5 mM) inhibits PTH secretion at 0.5 mM Ca2+ to the level observed with 2 mM Ca2+ alone; moreover, the effects of F- and high Ca2+ are not additive. While 1 mM F- suppresses PTH secretion by only 21%, and 10 microM Al3+ has virtually no effect at all, together they inhibit PTH release approximately to the level (63% inhibition) observed with 5 mM NaF alone. In the presence of 10(-5) M dopamine, F- produces a concentration-dependent inhibition of cAMP accumulation (0.684 +/- 0.033 pmoles/10(5) cells at 0 mM F- vs. 0.256 +/- 0.048 at 5 mM F-). However, the F- -induced decrease in cAMP cannot account for the inhibition of PTH release by this agent, since addition of methylisobutylxanthine (10(-4) M) by F- -treated cells raises intracellular cAMP content above that of control cells but fails to reverse the inhibition of PTH release. The cytosolic calcium concentration in Fura-2-loaded cells increases from 210 +/- 20 nM to 340 +/- 44 nM after 5 mM F- was added to incubation media. Prior removal of extracellular Ca2+ by EGTA totally blocks the F- -induced rise in cytosolic Ca2+ without preventing the inhibition of PTH release by NaF. F- also produces a time- and dose-dependent increase in the accumulation of IP, IP2, and IP3 in cells prelabeled with [3H]inositol and incubated with 10 mM Li+, consistent with activation of phospholipase C. We conclude that F- is a potent inhibitor of PTH secretion.(ABSTRACT TRUNCATED AT 400 WORDS)

An altered pattern of cross-resistance in multidrug-resistant human cells results from spontaneous mutations in the mdr1 (P-glycoprotein) gene

Multidrug resistance in human cells results from increased expression of the mdr1 (P-glycoprotein) gene. Although the same gene is activated in cells selected with different drugs, multidrug-resistant cell lines can be preferentially resistant to their selecting agent. The mdr1 cDNA sequence from vinblastine-selected KB cells, which are uniformly resistant to different lipophilic drugs, was compared with the corresponding sequence from colchicine-selected KB cells preferentially resistant to colchicine. These sequences differ at three positions, resulting in a single amino acid change in P-glycoprotein. These differences result from mutations that occurred during colchicine selection. The appearance of these mutations coincides with the emergence of preferential resistance to colchicine. We have constructed biologically active mdr1 cDNA clones that express either wild-type or mutant P-glycoprotein. Multi-drug-resistant transfectants obtained with the mutant sequence were characterized by increased relative resistance to colchicine compared with transfectants obtained with wild-type sequence. mdr1 mutations are therefore responsible for preferential resistance to colchicine in multidrug-resistant KB cells.

Characterization of the spectrum of postthymic T-cell malignancies in Taiwan. A clinicopathologic study of HTLV-1-positive and HTLV-1-negative cases

Postthymic T-cell malignancy shows marked geographic, clinicopathologic, and prognostic diversity. The frequency and spectrum of T-cell malignancies in Taiwan were investigated. Fifty-two patients (35 male and 17 female) with a median age of 49 years, were consecutively encountered between October 1983 and April 1987; these accounted for 39% of non-Hodgkin's lymphoma cases seen in our institutions. Ten patients (19.3%) had adult T-cell leukemia/lymphoma (ATL) associated with human T-cell leukemia virus (HTLV-1). Patients with ATL had disease similar to that reported from southwestern Japan and the Caribbean. They had frequent skin lesions (60%), hypercalcemia (40%), and a rapid clinical course with a median survival of 1.3 years. The 35 HTLV-1-negative peripheral T-cell lymphomas (PTL) were similar to PTL in western countries, manifesting frequent visceral, cutaneous, and vascular tropisms. Marrow involvement was documented at presentation in 39% and Stage III/IV disease in 80% of the PTL patients. The histology of PTL usually expressed prominent reactive features which is distinct from that in ATL. Several subcategories could be defined: Hodgkin's-like PTL in nine patients, T-zone lymphoma in three, angioimmunoblastic lymphadenopathy-like lymphoma in one, Lennert's lymphoma in three, and angioinvasive lymphoma in four. Two HTLV-1-negative PTL had neoplastic cells with clover-shaped nuclei and were designated as ATL-like. Morphologic classification based on the modified Working Formulation showed prognostic correlation, with median survival of less than 6 months for large cell/immunoblastic PTL, compared with 5 years for patients with small/medium cell PTL. Both low- and high-grade PTL seem to represent an incurable disease. Classical cutaneous T-cell lymphoma (seven cases) is relatively unusual in Taiwan, compared with the frequency of PTL. Post-thymic T-cell malignancies in Taiwan include HTLV-1-positive and HTLV-1-negative diseases, both of which have a poor prognosis and resemble similar T-cell malignancies in the East and West.

Twin study on myopia

In order to reassess the relative importance of genetic and environmental factors in the development of myopia in Chinese schoolchildren, 90 pairs of MZ and 36 pairs of like-sex DZ twins were enrolled for detailed ophthalmological examination about their ocular refractions. Corneal curvatures and axial lengths were also measured. With equivalent settings of the range for concordance, corneal curvatures showed higher concordance rate (84%) than ocular refractions (65%) and axial lengths (59%) in MZ twins. F-test on the intrapair variances between MZ and DZ twins revealed a significant hereditary role in determining the ocular refraction and its optical components. The degree of genetic determination was expressed by heritability indices, which were derived from intraclass correlation coefficients. The diversity of sample ages and refractions, while making the obtained data difficult to further explore the gene-environment interaction, led to the observation of more intrapair differences with age and myopic progression in MZ twins.

High osmolality: a potent parathyroid hormone secretogogue in dispersed parathyroid cells

We have examined possible mechanisms by which osmolality might modulate PTH secretion in dispersed bovine parathyroid cells. Increasing medium osmolality by adding sodium chloride causes a marked, dose-dependent increase in PTH release. The maximum effect (4-fold increase) is observed when osmolality is around 650 mosM, with half-maximal stimulation at about 400 mosM. When osmolality is increased to a similar extent with either sucrose or sodium chloride, PTH secretion is enhanced to a comparable degree, suggesting that osmolality itself, rather than ionic strength, is responsible for the increase in PTH secretion. Time course experiments show that the increased secretion of PTH with high osmolality occurs very rapidly (in less than 5 min). In contrast to the suppressive effects of high Ca2+ on PTH release, increasing calcium concentration in the incubation media does not inhibit the stimulation of PTH secretion by high osmolality. Moreover, the effects of dopamine (10(-5) M) and high osmolality on PTH release are additive, further suggesting that high osmolality and cAMP modulate PTH release by different mechanisms. In fact, direct measurement of cellular cAMP in cells exposed to high osmolality shows no change relative to control cells incubated with normal osmolality, 127 +/- 20 vs. 146 +/- 21 fmol/10(5) cells, respectively. Cytosolic Ca2+ increases from 257 +/- 29 nM to 703 +/- 50 nM after 200 mM NaCl is added to the incubation medium at low Ca2+ (0.5mM). Prior removal of extracellular calcium abolished this effect. Increasing the osmolality to a similar level by adding sucrose to the medium does not demonstrate any increase in cytosolic calcium. We conclude that high osmolality is a potent secretogogue in dispersed bovine parathyroid cells. Unlike dopamine and isoproterenol, high osmolality does not act through changes in intracellular cAMP. It also prevents the normal inhibitory effect of high Ca2+ on PTH release. Change of cytosolic Ca2+ is variable and suggests that the effect of high osmolality on PTH release cannot be explained by cytosolic Ca2+ alone. Further understanding of the mechanisms by which osmolality affects PTH release, therefore, may provide clues to the unusual inverse relationship between extracellular and cytosolic calcium and PTH release.

Antibodies to Epstein-Barr virus-specific DNase in patients with nasopharyngeal carcinoma and control groups

Serum samples from 154 patients with nasopharyngeal carcinoma (NPC), 374 with other cancers, 1,000 normal controls from Government Employees' Clinic Center (GECC), and 3,642 individuals of various ethnic-dialect groups living in high-risk areas for NPC were collected and the concentration of antibodies to Epstein-Barr virus (EBV)-specific DNase activity was determined. Taking a serum sample where 1 ml will neutralize two or more units of the DNase activity as positive, 2-4 units as low level, 4-6 units as medium level, and more than 6 units as a high level of antibody, 90.3% of the NPC patients contained significant amounts of antibodies to EBV-specific DNase activity and most of those had high levels of the antibody. In contrast, only 11% of sera from patients with cancers other than NPC contained antibodies to EBV-specific DNase activity, and high levels were very rare (2.1%). The difference in positive rates between these two groups is highly significant according to the chi 2 test (P less than 0.001). The positive rate of this antibody in the control group (GECC) was 5.3% with 0.0%, 0.8%, and 4.5% having high, medium, and low levels of antibodies, respectively. Again, the difference in positive rates between the GECC group and the NPC group is statistically significant (P less than 0.001). Taken separately, the positive rates of anti-EBV DNase activity in the three high-risk groups were 11.7%, 13.0%, and 13.1%. No significant difference in age distribution for the levels of this antibody was observed in the control GECC group or the three high-risk groups. However, the positive rates of the three high-risk groups are more than twice those of the GECC group (11.7% approximately 13.1% vs 5.3%). This ratio coincides with the ratio of the probability of developing NPC in high-risk groups compared to that of the GECC group (also more than two times). The significance of this coincidence is discussed.

Effects of extracellular calcium and magnesium on cytosolic calcium concentration in Fura-2-loaded bovine parathyroid cells

A newly developed calcium-sensitive dye, Fura-2, was employed in dispersed bovine parathyroid cells to study the effects of extracellular calcium and magnesium on cytosolic calcium concentration and parathyroid hormone (PTH) release. In comparison with control cells, Fura-2-loaded parathyroid cells showed the same maximal rate of PTH release, set-point for extracellular Ca++ (the calcium concentration producing half of the maximal inhibition of PTH release), and maximal inhibition of PTH release (71.6%) by high extracellular Ca++. At an extracellular Mg++ concentration of 0.5 mM, raising extracellular Ca++ in a stepwise fashion from 0.5 mM to 2.0 mM produced a dose-dependent, statistically significant (p less than 0.01) increase in cytosolic Ca++ from 198 +/- 24 nM (0.5 mM Ca++) to 411 +/- 21 nM (2.0 mM Ca++) which closely paralleled the concomitant decrease in PTH release. An elevation of extracellular Mg++ from 0.5 mM to 5 mM, at an extracellular Ca++ of 0.5 mM, resulted in a transient spike of cytosolic Ca++ which lasted for approximately 30 seconds, followed by a small but stable increase in the cytosolic Ca++ concentration (174 +/- 7 nM vs. 237 +/- 10 nM, n = 4, p less than 0.01). Prior removal of extracellular calcium by addition of an excess of EGTA did not abolish the transient spike induced by high extracellular magnesium concentrations in Fura-2-loaded cells, suggesting that this rapid increase in cytosolic Ca++ arises, at least in part, from intracellular stores of Ca++. This is supported by the observation that pretreating cells with ionomycin resulted in disappearance of the magnesium-induced spike.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiological characteristics of twinning rates in Taiwan

Delivery records of public hospitals and birth certificates of household registration offices were examined to study the epidemiological characteristics of twinning rate from 1955 to 1984 in Taiwan. The MZ twinning rate was consistently higher than the DZ rate during the study period. The DZ rate declined steadily from 2.7 per 1000 in 1955 to 1.3 per 1000 in 1975, and then gradually increased to 3.6 per 1000 in 1984. The MZ rate peaked periodically in 1956, 1966 and 1976, and gradually increased from 3.3 per 1000 in 1978 to 5.9 per 1000 in 1986. Both MZ and DZ rates were higher in urban than in rural areas and they were also higher in northern Taiwan than elsewhere in the island. While both MZ and DZ rates increased with maternal age and parity, the maternal age difference and the parity difference were more striking in DZ than in MZ rates. The international comparison also showed a greater racial difference in maternal age-specific DZ than MZ twinning rates; and the older the maternal age, the greater the international discrepancy in DZ rates.

Lactose malabsorption and small-intestinal lactase in normal Chinese children

A total of 852 healthy Chinese children from 1 month to 14 years of age were investigated for lactose malabsorption using the breath hydrogen test. A lactose load of 2 g/kg was administered to 528 children and 1 g/kg to another 324 children. The incidence of lactose malabsorption was significantly different among various age groups and between the two different lactose dosages. While the incidence of malabsorption increased strikingly from the age of 3 to the age of 5 years, the age effect remained constant after the age of 6 years. The lactose load of 2 g/kg induced a higher incidence of malabsorption in study subjects than 1 g/kg did, and the dose effect increased for those aged below 5 years and decreased above 5 years. Small-intestinal lactase was also studied in 34 children aged from 2 months to 15 years. The lactase activity was highest in children 2 years old or younger, gradually decreasing with increasing age. In conclusion, lactase activity in Chinese children decreases gradually after 3 years of age, a finding that correlates well with the results of the breath hydrogen test.

The human multidrug resistance (mdr1) gene. cDNA cloning and transcription initiation

Multidrug resistance in human KB carcinoma cells selected for resistance to colchicine, vinblastine, or adriamycin results from overexpression, and frequently amplification, of a specific gene (mdr1). Overlapping cDNA clones representing a complete 4.7-kilobase mdr1 transcript have been obtained from multidrug-resistant KB cells. Primer extension and S1 nuclease protection experiments show that two transcripts initiate 136 and 140 bases upstream from the first ATG codon in all human multidrug-resistant cell lines. The mdr1 gene is expressed in human normal kidney cells and HepG2 liver cells as a poly(A)+ RNA which starts from the same sites. Less prominent transcripts were found to initiate 155-180 bases upstream from the first ATG codon in vinblastine- or adriamycin-selected cell lines and 480-630 bases upstream in colchicine-selected cell lines. Southern hybridization analyses with different portions of a full-length cDNA indicate that the human mdr1 gene encompasses at least 70 kilobases of DNA amplified in all highly multidrug-resistant cell lines.

Mortality of hepatoma and cirrhosis of liver in Taiwan

A study of mortality from hepatoma and hepatic cirrhosis was conducted in Taiwan, where their mortality rates are among the highest in the world in 1980 being 26.10 and 8.14 per 100,000 population for males and females, respectively, for hepatoma, and 33.01 and 12.90 for males and females, respectively, for cirrhosis. The secular trends of hepatoma and hepatic cirrhosis death rates have been increasing, especially in males, with consequent increase in the sex ratio. The large difference in mortality rates between males and females and the increasing trends in the sex ratio suggest that other factors besides hepatitis B virus (HBV), are involved in the aetiology of hepatoma and cirrhosis of liver.

Internal duplication and homology with bacterial transport proteins in the mdr1 (P-glycoprotein) gene from multidrug-resistant human cells

Resistance of tumor cells to multiple cytotoxic drugs is a major impediment to cancer chemotherapy. Multidrug resistance in human cells is determined by the mdr1 gene, encoding a high molecular weight membrane glycoprotein (P-glycoprotein). Complete primary structure of human P-glycoprotein has been determined from the cDNA sequence. The protein, 1280 amino acids long, consists of two homologous parts of approximately equal length. Each half of the protein includes a hydrophobic region with six predicted transmembrane segments and a hydrophilic region. The hydrophilic regions share homology with peripheral membrane components of bacterial active transport systems and include potential nucleotide-binding sites. These results are consistent with a function for P-glycoprotein as an energy-dependent efflux pump responsible for decreased drug accumulation in multidrug-resistant cells.

Snowflake degeneration: an independent entity or a variant of retinitis pigmentosa?

We examined eight members of three generations of a family with a history of hereditary retinal degenerative disease. Four affected members have multiple whitish retinal dots resembling snowflakes. Other positive ocular findings in the four members with retinal flakes include myopia, cataract, fibrillary vitreous degeneration with occasional strands, attenuated retinal arterioles, sheathed retinal vessels, occlusion of small retinal vessels, white with and without pressure, annular macular pigment defects, and occasional spicules of pigment. Goldmann perimetry showed irregular annular scotomas in three patients. Electroretinographic response was extinguished in one and subnormal in three. Electro-oculography showed the light rise-to-dark trough ratio to be decreased in the affected patients. Based on results of vitreoretinal biomicroscopy, Goldmann perimetry, and visual electrodiagnostic testing, we suspect that snowflake degeneration may be just a variant of retinitis pigmentosa.

Bee sting-induced ocular changes

A six-year-old boy was stung by a bee on his right cornea. A severe conjunctival injection, chemosis, marked corneal edema, and hyphema developed. A partially dislocated lens, partial iris atrophy, and cataract formation were subsequently noted. He was treated with systemic and topical corticosteroids. Later, the subluxated cataract was removed through the pars plana approach.

Risk factors for nasopharyngeal carcinoma

In an effort to assess the relative importance of various risk factors of nasopharyngeal carcinoma (NPC), which includes antibodies to Epstein-Barr virus capsid antigen (anti-VCA) and early antigen (anti-EA) as well as other environmental factors, a multivariate logistic regression method was applied to analyze previously collected data from an epidemiologic study on 343 cases with NPC and 1017 neighborhood controls. Anti-VCA and anti-EA titers were found significantly associated with NPC. The relative risk increased with the increase of antibody titers. Individuals who smoked 30 or more cigarettes per day had more than 3.4 times higher risk than those who never smoked, while no increase in the risk was observed for those smoking less than 20 cigarettes per day and ex-smokers. Use of herb drugs, working under poor ventilation and nativity were also found to increase the NPC risk. In cases other than smoking 20 or more cigarettes per day and the frequent use of herb drugs, the synergistic interaction was not observed. In addition, male NPC individuals and Mainland Chinese were found to have relatively lower antibody titers as compared with female individuals or native Taiwanese.

A new antitumor antibiotic, chounghwamycin A. I. Taxonomy, isolation and characterization

Chounghwamycin A, a new antitumor antibiotic produced by a strain of Streptomyces sp. No. PL-D-5, was isolated and characterized. It appeared to belong to the actinomycin group of antibiotics from physico-chemical studies and has an empirical formula of C63H88N11O21. The antibiotic is extractable into an organic solvent from the fermentation broth, possessing potent antileukemic activity against P388 mouse leukemia in mice and antimicrobial activity against Gram-positive bacteria with MIC values about 0.1-0.4 microgram/ml, but showed no activity on Gram-negative bacteria, yeast and fungi tested.

A retrospective study on malignant neoplasms of bladder, lung and liver in blackfoot disease endemic area in Taiwan

A total of 69 bladder cancer, 76 lung cancer and 59 liver cancer deceased cases and 368 alive community controls group-matched on age and sex were studied to evaluate the association between high-arsenic artesian well water and cancers in the endemic area of blackfoot disease (BFD), a unique peripheral vascular disease related to continuous arsenic exposure. According to a standardized structured questionnaire, information on risk factors was obtained through proxy interview of the cases and personal interview of the controls. A positive dose-response relationship was observed between the exposure to artesian well water and cancers of bladder, lung and liver. The age-sex-adjusted odds ratios of developing bladder, lung and liver cancers for those who had used artesian well water for 40 or more years were 3.90, 3.39, and 2.67, respectively, as compared with those who never used artesian well water. Multiple binary logistic regression analyses showed that the dose-response relationships and odds ratios remained much the same while other risk factors were further adjusted.

Malignant neoplasms among residents of a blackfoot disease-endemic area in Taiwan: high-arsenic artesian well water and cancers

The objective of this study is to elucidate the association between high-arsenic artesian well water and cancers in endemic area of blackfoot disease, a unique peripheral vascular disease related to continuous arsenic exposure. As compared with the general population in Taiwan, both the standardized mortality ratio (SMR) and cumulative mortality rate were significantly high in blackfoot disease-endemic areas for cancers of bladder, kidney, skin, lung, liver, and colon. The SMRs for cancers of bladder, kidney, skin, lung, liver, and colon were 1100, 772, 534, 320, 170, and 160, respectively, for males, and 2009, 1119, 652, 413, 229, and 168, respectively, for females. A dose-response relationship was observed between SMRs of the cancers and blackfoot disease prevalence rate of the villages and townships in the endemic areas. SMRs of cancers were greater in villages where only artesian wells were used as the drinking water source than in villages using both artesian and shallow wells, and even greater than in villages using shallow wells only.

Antibody to Epstein-Barr virus-specific DNase as a marker for the early detection of nasopharyngeal carcinoma

We have previously shown that high levels of antibody to Epstein-Barr virus (EBV)-specific DNase may be a useful marker for the early diagnosis of nasopharyngeal carcinoma (NPC). Sera from 3,368 males in an area with a high risk for the development of NPC were examined for the presence of antibody to EBV-specific DNase activity. Significant levels of the antibody were found in 430 of these sera. As a result, 32 individuals have attended the out-patient department of otolaryngology for clinical examination. Among them, one individual was found to have a stage II nasopharyngeal carcinoma. This result supports the value of determination of antibody to EBV-specific DNase as a marker for the early detection of NPC.

Genetic and environmental effects on the development of myopia in Chinese twin children

In order to assess the relative and interactive importance of genetic and environmental components on the development of myopia in Chinese school children aged from 10 to 15 years, a population-based sample of 361 same-sexed twin pairs recruited through stratified cluster sampling was studied. Zygosity of twin pairs was determined by Mendelian traits, red cell antigen systems, and continuous dermatoglyphic characteristics; while myopia was diagnosed by both objective and subjective techniques. Studying and reading habit was obtained from cotwins and their parents through a life style questionnaire. Age-sex-adjusted concordance rate derived from multiple regression equation was used in the analysis. Conventional comparison of intrapair concordance between monozygotic (MZ) and dizygotic (DZ) twins was used to assess the importance of a genetic component in the determining of myopia, and a significant genetic influence was observed. Environmental influence on myopia was evaluated through MZ cotwin method, and MZ cotwins with concordant studying and reading habits were significantly more concordant in myopia than those MZ cotwins with discordant habits. The possible effect of gene-environment interaction on myopia was explored, and concordance in myopia was found significantly associated with the interaction between zygosity and habit of studying and reading. These observations suggested that the impact of the environmental factor on the development of myopia may be influenced by genotype, and vice versa.

Resonant, optical growth of submicrometer metal gratings

Submicrometer metal gratings are generated when adsorbed molecules on a dielectric substrate are photodissociated by two interfering laser beams. The measured surface photodissociation rate is greatly enhanced at specific grating spacings. This resonant growth has been interpreted as a coherent optical process coupled by the growing deposited structure.

Genetic variance and heritability of cardiovascular risk factors in Chinese adolescent twins

In order to estimate genetic variance and heritability of systolic blood pressure (SBP), diastolic blood pressure (DBP), serum cholesterol and triglyceride levels, a total of 235 (79 male and 82 female MZ, 41 male and 33 female DZ) twin pairs, recruited from 12 junior high schools in Taipei city, were studied. Statistically significant genetic variance observed for SBP, DBP, serum cholesterol and triglycerides persisted after adjustment for age and anthropometric characteristics. However, further adjustment for dietary preference, beverage consumption, and other host and environmental factors gave different results: genetic variance of adjusted SBP and DBP was still significant, while significance was found only in males for cholesterol and in neither males nor females for triglycerides. Heritability estimates of unadjusted SBP, DBP, cholesterol and triglycerides were 0.27, 0.45, 0.21 and 0.41, respectively, for males, and 0.15, 0.42, 0.41 and 0.82, respectively, for females. After adjustment for age, anthropometric characteristics, host and environmental factors, the heritability estimates of SBP, DBP and cholesterol were 0.64, 0.72 and 0.50, respectively, for males, and 0.40, 0.60 and 0.37, respectively, for females.

Experimental study of physiological pulsatile flow past valve prostheses in a model of human aorta--I. Caged ball valves

Pulsatile flow development past a caged ball valve in a model human aorta was studied using laser Doppler anemometry. Velocity profiles measured in the ascending aorta and in the mid-arch region were strongly influenced by the geometry of the valve at the root of the aorta. Velocity profiles distal to the valve were asymmetric with jet-like flow in the peripheral region having larger velocity magnitudes towards the left lateral wall. In early diastole, a streamwise vortex motion was observed throughout the model aorta with fluid moving towards the downstream direction along the left lateral wall and reversed flow along the right lateral wall. With the caged ball valve at the root of the aorta, no reversed flow was observed along the inner wall of curvature in the mid-arch region.

Experimental study of physiological pulsatile flow past valve prosthesis in a model of human aorta--II. Tilting disc valves and the effect of orientation

In Part II of this two paper sequence, pulsatile flow development past a tilting disc valve in a model human aorta has been studied using quantitative laser Doppler techniques. The valve was mounted in three different orientations with respect to the aortic root in this study. Under pulsatile flow, the region of flow reversal induced near the wall of the minor flow orifice extends to more than one tissue annulus diameter downstream from the valve into the ascending aorta. In a plane perpendicular to the tilt axis, a bi-helical secondary flow is induced distal to the valve. This secondary flow is further compounded by the multiple curvatures in the aorta. Hence the valve orientation affects the velocity profiles as far downstream as the mid-arch region as well as in the brachio-cephalic arterial branch. In the mid-arch region, a flow reversal along the entire cross-section is observed in early diastole for all the three orientations of the disc valve.

Epidemiological aspects of a poliomyelitis outbreak in Taiwan, 1982

Active surveillance was carried out to examine the epidemiological characteristics of an abrupt outbreak of poliomyelitis after a significant decline in incidence had resulted from a mass vaccination campaign. Through the intensive survey of private and public hospitals, a total of 1,058 paralytic cases were found with a sex ratio of 1.4. While the age-specific attack rate was highest for the age group of less than one year and decreased with increasing age, the age composition did show a greater proportion of higher age groups than in previous outbreaks. Among 901 cases with a known history of vaccination, about half had received no vaccination and only 9.7% had received three or more doses. The outbreak started on May 29th, peaked in late August and ended on November 1st. The epidemic spread from the north through the middle to the south of the island during this period. A simulated epidemic curve based on the Reed-Frost model fitted the observed one fairly well. Attack rates varied from county to county and were significantly associated with the community health status, vaccination coverage, and their interaction. Possible ways to prevent the epidemic are discussed.