Induced activity of adenine phosphoribosyltransferase (APRT) in iron-deficiency barley roots: a possible role for phytosiderophore production

To isolate the genes involved in the response of graminaceous plants to Fe-deficient stress, a protein induced by Fe-deficiency treatment was isolated from barley (Hordeum vulgare L.) roots. Based on the partial amino acid sequence of this protein, a cDNA (HvAPT1) encoding adenine phosphoribosyltransferase (APRT: EC 2.4.2.7) was cloned from a cDNA library prepared from Fe-deficient barley roots. Southern analysis suggested that there were at least two genes encoding APRT in barley. Fe deficiency increased HvAPT1 expression in barley roots and resupplying Fe to the Fe-deficient plants rapidly negated the increase in HvAPT1 mRNA. Analysis of localization of HvAPT1-sGFP fusion proteins in tobacco BY-2 cells indicated that the protein from HvAPT1 was localized in the cytoplasm of cells. Consistent with the results of Northern analysis, the enzymatic activity of APRT in barley roots was remarkably increased by Fe deficiency. This induction of APRT activity by Fe deficiency was also observed in roots of other graminaceous plants such as rye, maize, and rice. In contrast, the induction was not observed to occur in the roots of a non-graminaceous plant, tobacco. Graminaceous plants generally synthesize the mugineic acid family phytosiderophores (MAs) in roots under Fe-deficient conditions. In this paper, a possible role of HvAPT1 in the biosynthesis of MAs related to adenine salvage in the methionine cycle is discussed.

[Treatment by corticosteroid and plasma exchange in 5 cases of renal cholesterol embolic disease]

Cholesterol arterial embolization is a systemic disease resulting from cholesterol crystal embolization to multiple organs, including the kidney, skin, brain, eye, gastrointestinal tract and extremities. In general, it is associated with high morbidity and mortality, but no optimal treatment has yet been developed. In this paper, we report five patients with cholesterol atheroembolic renal failure. In three of the five patients, combined therapy with corticosteroids and plasma exchange was performed. The three patients survived. On the other hand, the two remaining patients died of multifactorial causes. In this report, the literature on steroid therapy for cholesterol atheroembolic renal disease is reviewed and the efficacy of combined therapy by use of corticosteroids and plasma exchange is evaluated.

[A case of Chinese herbs nephropathy in which the progression of renal dysfunction was slowed by steroid therapy]

The patients was a 43-year-old woman whose chief complaints were nausea and heaviness of the heads. There was a history of toxemia of pregnancy. The patient had previously taken Tenshin Tokishigyaku-ka-goshuyu-shokyo-to for two years because of cold sensitivity. Fever, thirst, and loss of appetite developed from approximately 18 months after she started treatment with the Chinese herbal preparation, and she presented at our outpatient clinic 2.5 years later. On initial examination, deterioration of renal function was evident and the serum creatinine level was 3.4 mg/dl. A renal biopsy specimen showed marked interstitial fibrosis without inflammatory cell infiltration, leading to the diagnosis of Chinese herbs nephropathy (CHN). Steroid therapy was started on the 36th hospital day after a sharp rise in the serum creatinine level to 5.1 mg/dl. This resulted in the rapid improvement of renal function and reduction of the serum creatinine to 2.6 mg/dl by 8 weeks after the initiation of treatment. In a study on the use of steroids for patients with progressive moderate renal dysfunction caused by Chinese herbs, Vanherweghem et al. reported that the progression of renal failure was appreciably slowed in patients given steroids when compared with the control group. We were also able to slow the progression of renal dysfunction in our patient by steroid therapy, although the prognosis of CHN is generally considered to be very poor.

Immunohistochemical localization of cytokines and cell adhesion molecules in maxillary sinus mucosa in chronic sinusitis

OBJECTIVE

Chronic sinusitis is a common disease characterized by persistent inflammation of the nasal and paranasal sinus mucosa. Accumulating evidence supports the importance of proinflammatory cytokines and endothelial cell adhesion molecule (CAM) expression as an initiating process in tissue inflammation. This study was conducted to investigate the localization of major cytokines and CAMs in the maxillary sinus mucosa from patients with chronic sinusitis and from normal subjects.

METHODS

Maxillary sinus mucosal specimens from patients with chronic sinusitis (n = 10) and from normal subjects (n = 6) were immunostained with specific antibodies directed against the cytokines (IL-1alpha, IL-1beta, IL-6, IL-8 and TNF-alpha) and the CAMs (intercellular adhesion molecule-1, ICAM-1 and vascular CAM-1, VCAM-1).

RESULTS

The number of immunoreactive cells for IL-1alpha, IL-1beta, IL-6, IL-8, and TNF-alpha was increased significantly in patients with chronic sinusitis compared with normal controls. Immunoreactivity for ICAM-1 was also increased significantly in patients with chronic sinusitis compared with normal controls, whereas VCAM-1 is only minimally expressed or is absent in both groups.

CONCLUSION

These findings indicate that bacterial and/or viral infection may induce functional and morphologic changes in the maxillary sinus mucosa in chronic sinusitis through enhanced generation of specific cytokines in conjunction with CAMs.

Involvement of tenascin-C in proliferation and migration of laryngeal carcinoma cells

Tenascin-C (TN-C) is an extracellular matrix glycoprotein upregulated in various pathological processes. In this study, we investigated its distribution in dysplasia and carcinoma of the human larynx using immunohistochemistry and in situ hybridization (ISH) techniques. In all cancer tissues, TN-C immunostaining was markedly increased in the stroma, especially around the cancer cell nests. In addition, cytoplasmic staining of cancer cells was also observed in 62.5% of the invasive cases, the cells being distributed in the periphery of the nests adjacent to the stroma. TN-C mRNA signals in cancer cells were detected in all six cases examined by ISH. Furthermore, in vitro evaluation of the roles of TN-C demonstrated an increase in the proliferating cell fraction in a dose-dependent manner. In a wound closure assay, the addition of TN-C promoted migration. We conclude that TN-C secreted by cancer cells may be involved in their proliferation and migration in an autocrine fashion.

Weakly bound calcium ions involved in the thermostability of aqualysin I, a heat-stable subtilisin-type protease of Thermus aquaticus YT-1

Aqualysin I is a heat-stable protease; in the presence of 1 mM Ca(2+), the enzyme is stable at 80 degrees C and shows the highest activity at the same temperature. After gel filtration to remove free Ca(2+) from the purified enzyme sample, the enzyme (holo-aqualysin I) still bound Ca(2+) (1 mol/mol of the enzyme), but was no longer stable at 80 degrees C. On treatment of the holo-enzyme with EDTA, bound Ca(2+) decreased to about 0.3 mol/mol of the enzyme. The thermostability of holo-aqualysin I was dependent on the concentration of added Ca(2+), and 1 mM added Ca(2+) stabilized the enzyme completely, suggesting that aqualysin I has at least two Ca(2+) binding sites, i.e. stronger and weaker binding ones. Titration calorimetry showed single binding of Ca(2+) to the holo-enzyme with an association constant of 3.1 x 10(3) M(-1), and DeltaH and TDeltaS were calculated to be 2.3 and 6.9 kcal/mol, respectively, at 13 degrees C. La(3+), Sr(2+), Nd(3+), and Tb(3+) stabilized the holo-enzyme at 80 degrees C, as Ca(2+) did. These results suggest that the weaker binding site exhibits structural flexibility to bind several metal cations different in size and valency, and that the metal binding to the weaker binding site is essential for the thermostability of aqualysin I.

Expression of tenascin-C and the integrin alpha 9 subunit in regeneration of rat nasal mucosa after chemical injury: involvement in migration and proliferation of epithelial cells

Nasal mucosa covered by pseudostratified ciliated epithelia can be injured by microbial infection and physical and chemical agents. To elucidate mechanisms of regeneration, erosion of rat nasal mucosa was produced by intranasal instillation of trichloroacetic acid, and tissue specimens were then sequentially obtained after 1-14 days. Since tenascin-C (TN-C) and its receptor, alpha 9 beta 1 integrin, are assumed to play important roles in regeneration of stratified squamous epithelia, their expression was evaluated by immunohistochemistry and in situ hybridization. Three to five days after the injury, TN-C mRNA was found in epithelial cells of migrating fronts and in epithelial sheets recovering ulcerated surfaces between the fronts and normal regions. TN-C deposition was increased under such sheets. Enhanced alpha 9 staining was also evident in the involved epithelium. 5-Bromo-2'-deoxyuridine incorporation assays revealed significant increase in proliferating cells in cell sheets over TN-C deposits at 3-7 days. Therefore, we conclude that regenerating epithelial cells produce and secrete TN-C, associated with an increase in alpha 9 expression, and that interactions between these molecules could regulate migration and proliferation of the epithelial cells in an autocrine manner.

Formate dehydrogenase, an enzyme of anaerobic metabolism, is induced by iron deficiency in barley roots

To identify the proteins induced by Fe deficiency, we have compared the proteins of Fe-sufficient and Fe-deficient barley (Hordeum vulgare L.) roots by two-dimensional polyacrylamide gel electrophoresis. Peptide sequence analysis of induced proteins revealed that formate dehydrogenase (FDH), adenine phosphoribosyltransferase, and the lds3 gene product (for Fe deficiency-specific) increased in Fe-deficient roots. FDH enzyme activity was detected in Fe-deficient roots but not in Fe-sufficient roots. A cDNA encoding FDH (Fdh) was cloned and sequenced. Fdh expression was induced by Fe deficiency. Fdh was also expressed under anaerobic stress and its expression was more rapid than that induced by Fe deficiency. Thus, the expression of Fdh observed in Fe-deficient barley roots appeared to be a secondary effect caused by oxygen deficiency in Fe-deficient plants.

No significant changes in levels of hepatitis C virus (HCV) RNA by competitive polymerase chain reaction in blood samples from patients with chronic HCV infection

To determine if levels of hepatitis C virus (HCV) RNA change over a several-year period, we quantified the amount of HCV RNA by competitive polymerase chain reaction. The population studied included 44 residents of a rural area with chronic HCV infection, 39 had chronic hepatitis C and 37 were patients on hemodialysis. All these Japanese patients had HCV RNA of genotype II. Blood samples were collected once a year from 1992 to 1995. From 1993 to 1995 between the groups, there was no significant difference in change of HCV RNA levels of 44 residents with chronic HCV infection, with and without liver dysfunction, nor was there any change in the 31 hemodialysis patients from 1992 to 1995. The HCV RNA levels in the 25 with chronic hepatitis who did not respond to interferon-alpha during 1992-1993 returned to pretreatment levels after the cessation of interferon treatment. In two of six hemodialysis patients who were infected with HCV during this observation period, HCV RNA was eliminated within one year, and the remaining four became HCV carriers. HCV RNA levels in the latter rose rapidly after infection and were sustained at a high level throughout the study period. Thus, HCV RNA level did not change remarkably during a three-year period, a finding which supports that it does not correlate with deterioration of liver damage and aging of HCV carriers.

Correlation between human T cell lymphotropic virus type-1 and Strongyloides stercoralis infections and serum immunoglobulin E responses in residents of Okinawa, Japan

To clarify the relationship between Strongyloides stercoralis, infection with human T cell lymphotropic virus type-1 (HTLV-1), and serum immunoglobulin E (IgE) levels, epidemiologic investigations of these two infections were conducted in inhabitants of Okinawa, a subtropical zone in Japan. Blood and feces samples were taken from 1,347 healthy inhabitants (554 males and 793 females). Antibody to HTLV-1 was measured by particle agglutination, enzyme-linked immunosorbent assay, and Western blotting. The presence of Strongyloides was determined by direct detection of rhabditiform larvae in fresh stool on agar-plate cultures. Serum IgE levels in 127 inhabitants were measured by a fluoroenzyme immunoassay. Antibody to HTLV-1 was detected in 23.0% of the blood samples and was more frequent in females (25.1%) than in males (20.0%) (P < 0.05). Strongyloides were detected in 21.9% of the feces samples and were more frequent in males (31.9%) than in females (14.9%) (P < 0.001). The prevalence of both infections increased with age, especially in persons 50 years of age and older: The prevalence of Strongyloides infection was significantly higher in HTLV-1 carriers (31.6%) than in those without HTLV-1 infection (P < 0.001). The level of IgE was low in HTLV-1 carriers, and significantly lower in HTLV-1 carriers than in noncarriers among inhabitants with Strongyloides infection. Both HTLV-1 and Strongyloides infections are endemic in the area studied.

Long term survey of hepatitis C virus infection in hemodialysis units in Fukuoka, Japan

To examine prevalence of hepatitis C virus (HCV) infection and liver dysfunction in hemodialysis units, we surveyed markers for HCV infection and serum alanine aminotransferase (ALT) in hemodialysis patients. 204 hemodialysis patients (111 men and 93 women; mean age, 53 +/- 12 years) in four hemodialysis units in Fukuoka, Japan were investigated. All serum samples were tested for antibody to HCV (anti-HCV) by second-generation enzyme-linked immunosorbant assay (ELISA). HCV RNA was detected to identify present HCV infection in the anti-HCV-positive patients by polymerase chain reaction (PCR) using primers deduced from the 5'-noncoding region. Liver dysfunction was defined as an elevated concentration of serum ALT (above 36 IU/liter) tested by a multiple autoanalyser. 105 patients (51.5 percent) were initially positive for anti-HCV, 95 (90.5 percent) of whom were also positive for HCV RNA. Ten became positive for anti-HCV in hemodialysis units during the observation, eight (80 percent) of whom had sustained HCV viremia. The route of transmission of HCV was not clear, but two of these patients had received blood transfusions. Of 95 patients with HCV viremia, 43 (45.3 percent) had had liver dysfunction at least once. In conclusion, HCV infection continues to occur in hemodialysis units not through blood transfusion and many of them become HCV carriers. Liver dysfunction was found in about a half of HCV-infected hemodialysis patients during the observation.

The active site of carboxypeptidase Taq possesses the active-site motif His-Glu-X-X-His of zinc-dependent endopeptidases and aminopeptidases

Carboxypeptidase (CPase) Taq possesses the His-Glu-X-X-His sequence, which is the consensus sequence in the active site of zinc-dependent endopeptidases and amino-peptidases, at positions 276-280. Amino acid replacement of the conserved His and Glu drastically diminished the activity of CPase Taq, and the zinc content of the enzyme was also greatly reduced when either of the two His residues was replaced with Arg or Tyr. The results indicate that this sequence actually functions as the active site in CPase Taq, showing that CPase Taq is a novel type of zinc-dependent CPase that possesses the His-Glu-X-X-His active-site motif.

Hepatitis C virus RNA levels determined by branched DNA probe assay correlated with levels assessed using competitive PCR

OBJECTIVE

To search for comparative differences, levels of hepatitis C virus (HCV) RNA were examined by branched DNA (bDNA) probe assay and by competitive polymerase chain reaction (PCR).

METHODS

The study population included 234 patients (chronic hepatitis 146, cirrhosis 36, hepatocellular carcinoma 52), all of whom were positive for HCV RNA, as determined by PCR. We quantified HCV RNA levels of all serum samples by both bDNA probe and competitive PCR.

RESULTS

HCV RNA was detected in serum samples by bDNA assay in 142 (60.7%) of the 234 patients; this rate was significantly higher in 106 (73.6%) of the 144 patients in genotype II than in 20 (41.7%) of 48 of genotype III and in 16 (38.1%) of 42 of genotype IV (p < 0.001, respectively). The median HCV RNA levels by bDNA assay (x 10(6) eq/ml) were 0.1, 0.1, 0.4, 1.4, and 5.3 among patients with HCV RNA levels < 3, 4, 5, 6, and 7 respectively, by competitive PCR (logarithmic transformation copy numbers/50 microliters). A significant correlation was found between HCV RNA levels by bDNA and competitive PCR (r = 0.5747, p < 0.001). There was a correlation among patients of genotype II and genotype III but not genotype IV.

CONCLUSION

We recommend bDNA assay for use in clinical practice because the procedure is not difficult and is less contamination-prone. The HCV RNA levels determined using this assay correlated with those examined by competitive PCR.

IL-1 beta and TNF-alpha produced by peripheral blood mononuclear cells before and during interferon therapy in patients with chronic hepatitis C

We investigated the spontaneous and phytohemagglutinin-stimulated production of interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) by peripheral blood mononuclear cells in patients with chronic hepatitis C during treatment with interferon-alpha (IFN-alpha). Spontaneous productions of these were significantly higher in patients with chronic hepatitis C than in healthy subjects. For patients prescribed interferon, stimulated production of TNF-alpha was significantly higher in complete responders than in partial responders, but the differences were small between the other cytokine levels and outcome of IFN treatment. Spontaneous production of these cytokines was higher in patients with genotype III with complete response than in genotype III patients with a partial response, but this was not the case in patients with genotype II. There was a negative correlation between these cytokines and histological activity index. Spontaneous production of cytokines was decreased only in complete responders after the administration of interferon. These data suggest that the elevated production of cytokines in patients with chronic hepatitis C may be due to host response to the virus, and monitoring cytokines along with alanine aminotransferase and hepatitis C virus RNA during treatment may provide more precise information of the effectiveness of therapy.

Evaluation of quantitative assay for antibody to hepatitis C virus core in patients treated with interferon

We titrated antibody to hepatitis C virus (anti-HCV) core of serum samples from 57 patients with chronic HCV infection, in an attempt to clarify the relationship between the level of HCV RNA and the outcome of interferon treatment. The patients studied were positive for both anti-HCV, by second-generation assay, and HCV RNA, by polymerase chain reaction, and had been treated with interferon for six months. Of the 57 patients, HCV RNA was eliminated in 16 by the time of discontinuation of interferon treatment (CR); in 19 this elimination was transient (PR) and for 22 elimination was nil (NR). The low HCV RNA level was accompanied by high titers of anti-HCV core while high HCV RNA levels were accompanied by low titers of anti-HCV core, with an inverse correlation (r = -0.322, P < 0.05). The mean titer of anti-HCV core before interferon treatment was 324 units in CR, 205 in PR, and 168 in NR, with a correlation ratio of 0.382 (P < 0.05). A decreased titer (more than 50%) was found in 68% of the CR. At the time of six-month follow-up, the anti-HCV core titers of CR had decreased by more than 50%, compared to pretreatment titers, while in PR and NR, there was an increase to above the pretreatment titers, without increases in HCV RNA levels or worsening of the hepatitis. In conclusion, quantitative assay for anti-HCV core is useful to assess the status of HCV replication.

Serum levels of soluble interleukin-2 receptors and effects of interferon-alpha for patients with chronic hepatitis C virus

To characterize the role of serum soluble interleukin-2 receptor (sIL-2R) in hepatitis C virus (HCV) infection, the level of sIL-2R was measured by ELISA in 117 subjects with chronic HCV infection and in 23 healthy controls. HCV RNA was detected by polymerase chain reaction in all subjects with HCV infection. Forty-seven patients with chronic hepatitis and 10 with liver cirrhosis were treated for six months with natural interferon-alpha. The sIL-2R levels of 40 asymptomatic HCV carriers (632 +/- 340 units/ml), 47 patients with chronic hepatitis (547 +/- 204 units/ml), 10 with cirrhosis (679 +/- 239 units/ml, and 20 with hepatocellular carcinoma (1145 +/- 487 units/ml) were significantly higher than those of healthy controls (380 +/- 191 units/ml) (P < 0.05, respectively). The levels of sIL-2R increased, as did the histological activity index scores (r = 0.348, P < 0.01). The level of sIL-2R rose after the initial administration of interferon in all 57 patients. In patients whom HCV RNA was eliminated from the sera within a six-month follow-up after cessation of treatment, the level of sIL-2R reverted to basal values, but in patients in whom HCV RNA was not eliminated the value was significantly higher than that before treatment. These results suggest that monitoring serum sIL-2R in patients with chronic HCV infection treated with interferon may provide information concerning the possibility of the elimination of HCV RNA.

Transmission of hepatitis C virus by health care workers in a rural area of Japan

OBJECTIVE

The prevailing route of hepatitis C virus (HCV) transmission in Japan is unclear, so we expected that a survey of routes of HCV infection in an endemic area might clarify the mode of transmission.

METHODS

We screened 2049 inhabitants in an isolated rural village of Fukuoka, Japan using HCV markers. All serum samples were assayed for antibody to HCV (anti-HCV) (ELISA), and anti-HCV-positive samples were assayed for HCV RNA and genotype (polymerase chain reaction).

RESULTS

The prevalence of anti-HCV was 19.7% and increased with advancing age, from zero in the under 19 yr of age group to 30.7% in the 60-69 yr of age group. HCV RNA was detected in 82.9% of the anti-HCV-positive inhabitants, and 88.3% of them had genotype II. Anti-HCV was detected in 17.8% of the children of HCV-carrier mothers, similar to the rate (15.4%) for all inhabitants in the 40-49 yr of age group, the same age group for the mean age of the anti-HCV-positive children. Anti-HCV was detected in 34.8% of husbands of female HCV carriers and in 22.2% of wives of male HCV carriers, similar to the rates (36.2% in males and 26.6% in females) for all inhabitants in 60-69 yr of age group, the same age group for the mean ages of carriers' spouses. The prevalence of anti-HCV was the highest in inhabitants of one of three distinct areas of this village where patients had often been injected with insufficiently sterilized syringes and needles for treatment in the same clinic.

CONCLUSION

These observations suggest that medical intervention probably played a more important role in the spread of the HCV infection in the village studied than did familial transmission.

Relationship of genotype to level of hepatitis C viraemia determined by competitive polymerase chain reaction

To compare the levels of hepatitis C virus (HCV) viraemia in carriers of the same genotype in various stages of chronic HCV infection, we quantified the amount of HCV RNA by competitive polymerase chain reaction and determined HCV genotype using type-specific primers. The study population included 255 patients with chronic HCV infection (asymptomatic 33, chronic hepatitis 141, liver cirrhosis 50, hepatocellular carcinoma 31). Of these 255, the prevalence of HCV RNA genotype II was 67.8%, genotype III, 17.3% and genotype IV, 14.9%; no genotype I was found. The level of HCV RNA (logarithmic transformed copy numbers per 50 microliters of serum) was significantly higher in subjects of genotype II than in those of genotypes III or IV (mean titre 5.8 +/- 1.0 vs. 5.1 +/- 1.2 and 4.8 +/- 1.1, P < 0.05, respectively). There was no significant difference in the level of HCV RNA between genotypes III and IV. Of 173 patients of genotype II, there were no significant differences between the level of HCV RNA and the stage of liver disease or in the level of HCV RNA by age. Of the 129 with genotype II with a history of blood transfusion, there was no significant difference between the level of HCV RNA of patients with and without a history of transfusion or between that of patients with a history of blood transfusion and the time elapsed since blood transfusion. The level of HCV viraemia depended on the genotype of HCV RNA and did not correlate to age or to the stage of liver disease.(ABSTRACT TRUNCATED AT 250 WORDS)

[Evaluation of three kinds of assays for the presence of antibody to hepatitis C virus (anti-HCV) and the association of them with HCV RNA]

In order to evaluate the feasibility for the detection of antibody to hepatitis C (anti-HCV), the first generation assay (c100-3 Ab) and two second generation assays (2nd EIA and 2nd PHA) were used to test 477 individuals who visited the medical hospital or clinics in Iki Island, Nagasaki Prefecture. HCV RNA, antibody titer by 2nd PHA and four kinds of antibody to epitope of HCV by RIBA II were also surveyed to determine their association with these three assays. Prevalence of anti-HCV was 26.6% by c100-3, 38.8% by 2nd PHA and 39.6% by 2nd EIA, indications that the 2nd generation assays are much more sensitive than c100-3. Prevalence of HCV RNA was 82.1% among 190, anti-HCV positive individuals; 100% among 52 individuals with liver disease, but only 75.4% in those without liver disease. HCV antibody titer, over 2(11) was higher among those who were positive for HCV RNA than those negative for HCV RNA. Four antibodies by RIBA II were all positive and reacted strongly when they were positive for HCV RNA, but only antibody to core antigen was observed among those negative for HCV RNA, suggesting that only antibody to core antigen remains in those with past HCV infection.

Inverse correlation between the titre of antibody to hepatitis C virus and the degree of hepatitis C viraemia

We titrated 277 hepatitis C virus (HCV) antibody-positive serum samples from 235 volunteer blood donors as well as from 42 outpatients of a hospital for elderly people and studied the relation of the titre of HCV antibody to the presence of HCV RNA, of antibody to C100 protein (anti-c100) and of antibody to GOR epitope (anti-GOR). Liver dysfunction was measured also. Of 177 HCV RNA-positive serum samples, 87 were tested for the degree of HCV viraemia by means of a competitive assay. Among the 277 samples, prevalences of HCV RNA, anti-c100, anti-GOR and liver dysfunction were 63.9%, 71.8%, 75.7% and 17.5%, respectively. The prevalence of HCV RNA became higher as the titre of HCV antibody increased. The titre tended to increase with age but the tendency was not statistically significant. The mean titre was higher in females (2(10.4 +/- 1.8)) than in males (2(9.4 +/- 2.2)) (P < 0.01). In the HCV RNA-positive serum samples, the HCV antibody titre was significantly higher in the anti-c100-positive samples than in the negative ones. This difference between the positive and negative samples, however, was not statistically significant for anti-GOR and liver dysfunction. Low degrees of HCV viraemia were accompanied by high titres of HCV antibody while high degrees of HCV viraemia went with low titres of HCV antibody. The study revealed that titres of HCV antibody were higher in females and the degree of HCV viraemia correlated inversely with the titre of HCV antibody.

Carboxypeptidase Taq, a thermostable zinc enzyme, from Thermus aquaticus YT-1: molecular cloning, sequencing, and expression of the encoding gene in Escherichia coli

The gene for carboxypeptidase Taq, a thermostable metallo-carboxypeptidase from Thermus aquaticus YT-1, was cloned and sequenced. The gene comprised an open reading frame of 1,536 base pairs with a GTG initiation codon and a TGA termination codon, which encodes a protein of 56,210 Da consisting of 511 amino acid residues. The GTG initiation codon of the gene was replaced with ATG by site-directed mutagenesis, and then the gene was expressed in Escherichia coli. The enzyme purified from E. coli cells showed the same properties as those of carboxypeptidase Taq prepared from T. aquaticus cells. Analysis for metal ions bound to the enzyme found that one molecule of the enzyme contains one tightly bound zinc ion. Comparison of the entire sequence showed that the enzyme has no obvious sequence similarity to any other metallo-peptidases. However, a His-Glu-X-X-His sequence, which is a conserved sequence in the active site of zinc-dependent endopeptidases and aminopeptidases, was found at positions 276 to 280 of the enzyme. These findings suggest that carboxypeptidase Taq is a novel type of zinc-dependent metallocarboxypeptidase.

Seroepidemiology of hepatitis C virus infection in hemodialysis patients and the general population in Fukuoka and Okinawa, Japan

In 1992, a seroepidemiologic study was carried out among hemodialysis patients and the general population in Fukuoka and Okinawa, Japan to determine the presence of hepatitis C virus (HCV) infection and HCV viremia. The markers used were antibody to HCV, determined by second-generation assay (anti-HCV), and HCV RNA, determined by the polymerase chain reaction. The prevalence of anti-HCV in Fukuoka was 3.3%, 73 per 2237 persons, significantly (P < 0.001) higher than the 0.4%, 5 per 1295, in Okinawa. The prevalence of anti-HCV in hemodialysis patients in Fukuoka was 51.9% (161 of 310 patients), significantly (P < 0.001) higher than the 9.1% (13 of 143 patients) in Okinawa. The ratio of HCV RNA-positive to anti-HCV-positive persons was significantly higher in hemodialysis patients (147/174, 84.5%) than in the general population (49/78, 62.8%) (P < 0.001). Elimination of HCV among hemodialysis patients appears to be difficult, as such patients have lower immune responses than the general population. In Fukuoka, but not in Okinawa, blood used for transfusion was supplied by paid donors at commercial blood banks from 1953 to 1969. This may explain why HCV infection is endemic in Fukuoka and not in Okinawa. Differences between the prevalence of anti-HCV in the hemodialysis patients in Fukuoka and Okinawa reflect differences in the prevalence in the general population in these two areas of Japan.

Prevalence and role of hepatitis C viraemia in haemodialysis patients in Japan

A second generation assay for antibody to hepatitis C virus (anti-HCV) was used in order to establish the exact prevalence of HCV infection in haemodialysis patients. HCV RNA was sought by the polymerase chain reaction in order to determine whether haemodialysis patients with anti-HCV had been infected with HCV in the past or were presently infected. Of 357 patients, 198 (55.5%) were positive for anti-HCV, compared to 113 (31.7%) positive for original antibody to c100-3 protein (P < 0.001). HCV RNA was detected in 171 (86.4%) of the 198 patients with anti-HCV. Liver dysfunction was found in 63 (17.6%) of all haemodialysis patients. Of these, 55 (87.3%) had HCV infection, one (1.6%) hepatitis B virus infection while, in the remaining seven, the origin was unknown. Thus, in almost all anti-HCV-positive patients, HCV viraemia was present. We conclude that HCV is an important cause of liver disease in haemodialysis patients.

Detection of HCV RNA in subjects with antibody to hepatitis C virus among the general population of Fukuoka, Japan

Volunteer blood donors and aged people who came to hospitals for a thorough physical checkup were surveyed to evaluate the exact prevalence of hepatitis C virus (HCV) infection in the general population of Fukuoka, Japan. We tested for antibody to HCV (anti-HCV) by second-generation assay and, to distinguish active HCV infection from past resolved infection, we tested for HCV RNA in reactive serum samples by polymerase chain reaction. The prevalence of anti-HCV was 286 (2.0%) of 14,341 subjects, increasing with advancing age, from 0.4% in the under-29 age group to 12.0% in the over-70 age group. There were no differences between sexes. HCV RNA was detected in 170 of 286 (59.4%) anti-HCV-positive subjects. The ratio of HCV RNA-positive to anti-HCV-positive subjects was higher in males than in females (P < 0.05) and decreased with advancing age, from 72.2% to 46.5%. The prevalence of elevated alanine aminotransferase (ALT) was only 15.9% in subjects with HCV RNA, higher in males (21.4%) than in females (8.3%) (P < 0.05). This study revealed that the prevalence of anti-HCV was high in the aged population, but that the ratio of HCV RNA-positive to anti-HCV-positive subjects was low, and most of the HCV RNA-positive subjects had normal ALT levels.