Vonoprazan prevents bleeding from endoscopic submucosal dissection-induced gastric ulcers.

BACKGROUND: Vonoprazan, a potassium-competitive acid blocker, is expected to improve the healing of endoscopic submucosal dissection (ESD)-induced gastric ulcers compared with proton pump inhibitors (PPIs). AIM: To compare the healing status of ESD-induced gastric ulcers and the incidence of post-ESD bleeding between subjects treated with vonoprazan for 5 weeks and those treated with PPIs for 8 weeks. METHODS: Patients in the vonoprazan group (n = 75) were prospectively enrolled, whereas patients in the PPI group (n = 150) were selected for a 2:1 matched historical control cohort according to baseline characteristics including gastric ulcer size immediately following ESD, age, sex and status of Helicobacter pylori infection. Two controls per case of vonoprazan-treated group were matched with a margin of 20% in terms of ulcer size and a margin of 5 years in terms of their age. RESULTS: Although a higher number of completely healed ulcers was observed in the PPI group (95/150, 63.3%) than that in the vonoprazan group (14/75, 18.7%; P < 0.001), the ulcer size reduction rates, which were 96.0 ± 6.7% in the vonoprazan group and 94.7 ± 11.6% in the PPI group, were not significantly different (P = 0.373). The post-ESD bleeding incidence in the vonoprazan group (1/75, 1.3%) was less than that in the PPI group (15/150, 10.0%; P = 0.01). The factors affecting post-ESD bleeding incidence were the type of acid secretion inhibitor (P = 0.016) and use of an anti-thrombotic agent (P = 0.014). CONCLUSION: Vonoprazan significantly reduced post-endoscopic submucosal dissection bleeding compared with PPIs.

Histochemistry of Ki-67 antigen in ameloblastomas.

The proliferative potential of two common histologic variants of ameloblastoma was investigated immunohistochemically using Ki-67 antibody on routinely processed, formalin-fixed, paraffin-embedded sections. Thirty cases of ameloblastomas (15 cases of follicular and 15 cases of plexiform type) were analyzed. Autoclave heating pretreatment was employed at 121 degrees C for 20 min prior to analysis. This retrieval method allowed immunoreactive sites of the Ki-67 antigen to become exposed and thus available for immunohistochemical reaction. We found that expressed Ki-67 antigen was localized within the nucleus of tumor cells in both follicular and plexiform ameloblastomas. Immunoreactive cells were localized in the peripheral area of tumor islands as well as in the central stellate reticulum-area. The labeling rate was higher in the plexiform (3.68%) than in the follicular type (1.78%). Results suggest that cell proliferation of ameloblastoma was different depending on histologic variation of the tumor. Further, the proliferative potential was higher in the plexiform ameloblastoma than that in the follicular type.

Correlation of E-cadherin and alpha-catenin expression with differentiation of oral squamous cell carcinoma.

The precise mechanism of disruption of cell-cell adhesion in oral squamous cell carcinomas has yet to be established. We therefore sought to clearly this mechanism by investigating expression of both E-cadherin (E-CD) and alpha-catenin (alpha-CAT), which is an intracellular CD-binding molecule, in squamous cell carcinomas of the tongue, gingiva and floor of the mouth using immunohistochemical and immunoblotting techniques. We found that reduced expression of both E-CD and alpha-CAT occurred more frequently in moderately- and poorly-differentiated carcinomas than in well-differentiated specimens (p < 0.001), and this reduced expression showed no regional specificity. Relatively frequent loss of alpha-CAT expression in poorly-differentiated carcinomas was detected by both immunohistochemical and immunoblotting analyses. These findings suggest that E-CD and alpha-CAT are both important regulators of intercellular adhesion, and that the reduction of these molecules is also linked to the process of tumor dedifferentiation.

Relationship of serum markers of hepatitis B and C virus replication in coinfected patients.

To evaluate viral interference between hepatitis B and C, we studied coinfected patients serologically and molecular biologically. Twenty-seven patients positive for hepatitis B surface antigen (HBsAg) and anti-hepatitis C virus (HCV) antibody, were classified into Groups BC-L and BC-H according to DNA-polymerase activity (less or greater than 100 cpm, respectively). Patients with hepatitis B or C alone were also enrolled as controls. HCV-RNA was detected more often in Group BC-L than in Group BC-H. Genotype 1b of HCV was determined in 75% of Group BC-H, 87.5% of Group BC-L, and 70.7% of hepatitis C-only patients. Activity of DNA-polymerase in coinfected patients was lower in patients positive for HCV-RNA as compared with those negative. HBsAg titers tended to be lower in coinfected patients than in patients with hepatitis B virus (HBV) alone. In conclusion, in coinfection, HBV may suppress the replication of HCV and HCV appears to reduce the expression of HBsAg and probably suppresses HBV replication.

Relationship between response to interferon therapy and detection of hepatitis C virus RNA by differential flotation centrifugation.

Circulating hepatitis C virus (HCV) particles can be fractionated by means of differential flotation centrifugation. It is reported that in the bottom fraction HCV is in the form immune complexes, whereas in the top, it is free of antibodies. We evaluated the significance of circulating complex and free HCV in chronic hepatitis C, and assessed the relationship in terms of the response to interferon (IFN) therapy. We examined sera before, just after, and 1 year after administering IFN to 18 patients with chronic hepatitis C, 10 of whom responded (group CR), and 8 did not (group NR). The amounts of virus were similar between both groups before therapy. After differential flotation centrifugation with 1.063 g/ml of NaCl, the top and bottom fractions were assayed for HCV RNA. Before therapy, HCV RNA was detected in the top fraction in 1 of 10 in group CR, and in 6 of 8 in group NR (P < 0.05, chi-square test). HCV RNA was positive in the bottom fraction of all samples. In a follow-up study of group NR, HCV RNA was detected in the top fraction in 3 of 8 just after IFN therapy, and in 7 of 8 after 1 year. This study suggests that the presence of HCV in the top fraction can predict a poor response to IFN therapy.

Detection of hepatitis C virus RNA in circulating immune complexes by RT-PCR.

BACKGROUND/AIMS: We investigate whether hepatitis C virus (HCV) forms a circulating immune complex (CIC) in patients with chronic HCV infection. MATERIALS AND METHODS: We examined HCV-RNA immunoprecipitated with anti-human IgG, A and M antibodies by reverse transcription-polymerase chain reaction. RESULTS: In thirty-nine (91%) of 43 patients, composed of 35 chronic hepatitis (CH) and 8 liver cirrhosis (LC), HCV-RNA was detected in the CIC. All 43 patients analyzed were classified into the following three categories; HCV-RNA was detected only in the supernatant (S pattern, 4 patients), both in the supernatant and the precipitate (SP pattern, 27 patients), and only in the precipitate (P pattern, 12 patients). SP pattern was most common in chronic HCV infection, and the frequency of SP pattern decreased with the progression of liver disease. P pattern was significantly more frequent in patients with higher gamma-globulin levels, histologically indicated LC, and antibody to HCV envelope protein. CONCLUSION: We found that HCV formed a CIC in most patients with chronic HCV infection, and that the formation of CIC might be related to the stage of chronic HCV infection.

Virological and serological characterization of asymptomatic blood donors positive for anti-hepatitis C virus antibody.

To study the virological and serological characteristics of asymptomatic hepatitis C virus (HCV) carriers, 165 blood donors positive for antibody against HCV proteins by the second generation assay, were analyzed for their clinical backgrounds, serological reactivity against antigens derived from HCV by recombinant immunoblot assay, and the amount and genotype of HCV by the polymerase chain reaction. Compared with blood donors having abnormal levels of alanine aminotransferase (ALT), sera from the donors with normal levels of ALT reacted less frequently against NS4 antigens (anti-5-1-1: 34.4% vs. 54.5%, P = 0.0609; anti-c100-3: 34.4% vs. 56.1%, P < 0.05). Also the positivity for antibodies against these antigens were more frequent in sera from donors with genotype 1b HCV-RNA than other genotypes (anti-5-1-1: 61.0% vs. 23.5%, P < 0.01; anti-c 100-3: 61.0% vs. 26.5%, P < 0.01). The prevalence of each genotype in blood donors with normal ALT levels was different from that in patients with advanced liver disease (P < 0.05), genotype 1b being less and genotype 2a being more frequent. The number of HCV-RNA copies/0.5 ml in donors with normal ALT was 10(7.9 +/- 1.0) (n = 27) and that in patients with chronic liver disease was 10(7.4 +/- 0.8) (n = 116), the difference being statistically significant (P < 0.05). In conclusion, the results of this study suggest that asymptomatic blood donors carrying HCV have the serological and virological characteristics different from the patients with advanced liver disease.

Establishment and characterization of a human tongue cancer xenograft line in nude mice.

We established a human tongue cancer (well-differentiated squamous cell carcinoma) xenograft line, LK-1, in nude mice. LK-1 showed logarithmic growth from 5 to 7 weeks after transplantation, and the take rate for 25 generations was 95.0%. We confirmed the expression of cytokeratins 1, 5, 7, 10, 14, 16, 17, 18 and 19, and type I, III, IV and V collagens by electrophoretical and immunohistochemical analyses. Although the amount of type I, IV and V collagens increased gradually from 5 weeks after transplantation, the distribution of type IV collagen was often discontinuous in the cancer basement membrane. From these data we concluded that LK-1 is an excellent model for the investigation of the cell biology of well-differentiated oral squamous cell carcinoma, and for examining the effects of clinical therapies for this disease.

Quantitation of hepatitis C virus RNA in liver tissue as a predictive marker of the response to interferon therapy in chronic hepatitis C.

Recently, factors predicting the response to interferon (IFN) therapy against hepatitis C virus (HCV) have received much attention. To evaluate the usefulness of the quantitation of intrahepatic HCV RNA as a predictive marker of the response to IFN therapy, we compared the amount of intrahepatic HCV RNA with serum levels in 16 patients. Eleven patients who had 10(10) copies/g or more of intrahepatic HCV RNA had increased level of serum alanine aminotransferase (ALT) after IFN therapy, while 4 of 5 patients who had less than 10(10) copies/g of intrahepatic HCV RNA achieved sustained normalization of serum ALT level and were designated as complete responders. Four complete responders possessed significantly less HCV RNA in the liver parenchyma than partial and nonresponders (P = 0.010, Mann-Whitney U-test), but the amount of HCV RNA in the serum was not significantly different between those groups. In conclusion, the results suggest that the quantitation of intrahepatic HCV RNA is a better indicator of the response to IFN therapy than serum HCV RNA.

Correlation of E- and P-cadherin expression with differentiation grade and mode of invasion in gingival carcinoma.

The expression pattern of two Ca(2+)-dependent cell-cell adhesion molecules, E- and P-cadherin (CD), in 25 primary gingival squamous cell carcinomas (SCC) was examined immunohistochemically. The occurrence of reduced-type expression of both E- and P-CD increased significantly with the grade of carcinoma differentiation, culminating in a complete loss of P-CD in poorly differentiated SCC. The occurrence of reduced-type P-CD expression also increased significantly with the mode of invasion, as was the case with E-CD. Furthermore, no P-CD molecules were detected in one of the six SCC having a diffuse, cord-like invasion and in three of the six having a diffuse type of invasion. These findings suggest that the down-regulation of these cell adhesion molecules closely correlates with the differentiation grade and mode of invasion of gingival SCC.

Cellular kinetics and lectin distribution in hamster buccal carcinomas.

As part of an evaluation of the progression to malignancy, the cellular kinetics of DMBA-induced tumors in the buccal mucosa of hamsters were examined using 5-bromodeoxyuridine (BrdU), peanut agglutinin (PNA), Ulex europaeus agglutinin I (UEA-I) and wheat germ agglutinin (WGA). BrdU-positive cells were localized in the basal layer in both normal and hyperplastic epithelium, whereas they were distributed from the basal to the prickle cell layer in squamous cell carcinoma (SCC). The extent of BrdU labeling increased as the tissues progressed towards malignancy. PNA and UEA-I showed binding only in the prickle cell layer of normal and hyperplastic epithelium, and WGA showed binding mainly in the prickle cell layer. However, in SCC, PNA and UEA-I showed no binding in the prickle cell layer and WGA binding was observed throughout the epithelium. A study of cellular kinetics using BrdU labeling and the lectin binding pattern may be useful in the evaluation of tissue changes on the way to malignancy.

Evaluation of antibody against AR142, a synthetic peptide derived from the core sequence of hepatitis C virus, in the diagnosis of non-A, non-B chronic liver disease.

We evaluated serum anti-hepatitis C virus (HCV) using a synthetic peptide (AR142) which includes an epitope in the core region of HCV. The incidence of anti-AR142 in 98 patients with type non-A, non-B chronic liver diseases (NANB-CLD) was 89.8%, while all the 28 patients with non-type C chronic liver diseases were negative for anti-AR142. Among 98 NANB-CLD patients, 74 were positive for both anti-AR142 and anti-C100-3, 23 showed discordant results, and one was positive for neither. Eighty-one NANB-CLD patients underwent reverse transcription-polymerase chain reaction assay to detect viremia and 76 (93.8%) had a detectable level of HCV-RNA. Titers of anti-AR142 were not different among groups of different disease activities, genotypes of HCV, nor amount of serum HCV-RNA. These observations suggest that anti-AR142 could be a useful marker for chronic HCV infection.

Application of in vitro bromodeoxyuridine labeling of oral cancers.

We used immunohistochemical methods to investigate whether in vitro labeling with bromodeoxyuridine (BrdU) of oral cancer tissues is useful in pathological diagnosis. BrdU-positive cells were found around the basal region of the epithelium in normal oral mucosa, in a papilloma specimen and in tissue with moderate dysplasia. The labeling rates (percentage of BrdU-positive cells, LR) for these cases were 1.2%, 6.9% and 7.5%, respectively. In well-differentiated carcinoma, more layers of BrdU positive cells were observed from the basal layer toward the surface. The LR in this region was 13.9-17.0%. In vitro BrdU labeling of oral tumors may be useful in pathological diagnosis, since the LR is lowest in normal tissues, higher in benign tumors, and highest in malignant tumor tissues.

Localization of E-cadherin adhesion molecules in human gingiva and gingival carcinoma.

Immunohistochemical investigations were carried out on the localization and expression of the Ca(2+)-dependent intercellular adhesion molecule E-cadherin in human gingiva and gingival carcinoma. Although E-cadherin did not appear in the parakeratinized layer of either clinically healthy or inflamed gingiva, it did appear strongly in the prickle layer and somewhat more weakly in the basal layer. Immunogold particles reactive to anti-E-cadherin monoclonal antibody in the electron microscopic findings were localized only in the vicinity of the desmosomes of the prickle and basal layers. In the case of gingival carcinoma, although E-cadherin was strongly expressed in the cells surrounding the keratinized region in the cancer nests, the expression decreased towards the marginal portion of the cancer nests. The distribution of E-cadherin in these cells may be dependent on the condition of the cancer cells that are potentially invasive. These findings suggest that cells of the parakeratinized layer of gingiva and cells of the marginal portion of the gingival carcinoma nests may easily detach or invade. In addition, the findings suggest that the gingival carcinoma used in this study tended to be invasive.