Renal handling of biphosphonate alendronate in rats.

Alendronate is a bisphosphonate that is secreted via a saturable pathway in rat kidney. This study is designed to discover if the rate-determining step in its net renal secretion is uptake into the renal tubule. The tissue uptake clearance of alendronate by the kidney, estimated from an integration plot analysis and normalized with respect to plasma protein binding, was 4.2 times higher at a tracer dose than that of inulin, indicating uptake of alendronate by the renal tubules. The uptake clearance is comparable with the net secretion clearance obtained from an infusion study, indicating that the rate-determining step in the net secretion is uptake under the tracer conditions. When the dose was increased, however, there was no reduction in uptake clearance while the net secretion clearance fell to almost zero. The urinary excretion clearance defined with respect to the steady state concentration in the kidney also fell to almost zero. This result suggests that saturation of the net secretion of alendronate is caused by saturation of membrane transport through the brush-border membrane. Thus, it would seem that there is a transport mechanism for alendronate on the brush-border membrane of kidney epithelial cells.

Microsatellite instability and K-ras mutations in gastric adenomas, with reference to associated gastric cancers.

Gastric adenomas are often detected in the stomach resected for gastric cancer. Previous investigation have revealed that the prevalence of their malignant transformation is generally low, but the frequent coexistence with carcinoma suggests that they may share some common processes with gastric cancer in tumorigenesis. In contrast to the cumulative information about genetic alterations in gastric cancer, inquiries into the genetic changes of adenoma and coexisting carcinoma in the same individual's stomach are still few. We investigated microsatellite instability (MSI) and K-ras point mutations in codons 12 and 13 in 50 lesions of gastric adenomas in 43 cases, and 31 lesions of gastric cancers that coexisted with these adenomas. In gastric adenomas, we found seven lesions (14.0%) to have microsatellite instability (MSI) at one or more loci, and most of them (six cases) had MSI at only one locus and were not associated with alterations in presumable target molecules. MSI was detected more frequently (11/31, 35.5%) and more extensively (five lesions at multiple loci) in accompanying gastric carcinomas. The prevalence of MSI in adenomas was more frequently found in those with synchronous gastric cancer (6/37, 16.2%, vs. 1/13, 7.6%) than without, and gastric adenoma accompanied by gastric cancer with multiple MSI tended to have MSI more frequently than that accompanied by cancer without MSI (4/5, 80%, vs. 1/24, 4.2%; p = 0. 01). In at least some individuals, MSI appears to represent one step in the pathway of gastric tumorigenesis, shared by adenoma and carcinoma. We found K-ras gene alteration in 8 lesions (16.0%) out of 50 gastric flat adenomas and no difference in its prevalence between adenoma with or without cancer. Only one gastric cancer, which had adenoma without K-ras mutation, had K-ras codon 12 mutation. Adenomas with a higher grade of atypia (p < 0.05) more frequently carried K-ras point mutation, which is consistent with the situation in colorectal adenoma. We conclude that MSI, not K-ras mutation, is a shared genetic alteration in adenoma and carcinoma of the individual stomach.

Ligand-induced downregulation of receptor-mediated clearance of hepatocyte growth factor in rats.

The change in tissue uptake clearance of 125I-labeled hepatocyte growth factor (HGF) after an intravenous injection of an excess (120 micrograms/kg) of unlabeled HGF was examined in rats. The heparin-washable component of the hepatic uptake clearance of 125I-HGF was only slightly changed, whereas the heparin-resistant component was significantly reduced 30 min after injection of excess HGF, followed by gradual recovery with a half-life of 3.2 h. Because the former clearance mainly represents 125I-HGF association with heparan sulfate proteoglycan on the cell surface and/or extracellular matrix, whereas the latter includes relatively specific clearance, such as receptor-mediated endocytosis, this result suggests that injection of excess HGF selectively causes downregulation of receptor-mediated HGF clearance in the liver. Downregulation could also be observed for HGF receptor density in isolated liver plasma membrane, assessed by Western blot analysis by means of anti-receptor antibody, 30 min after injection of excess unlabeled HGF, supporting the hypothesis that the overall elimination of HGF from the systemic circulation can be affected by a change in HGF receptor density on the liver cell surface.

Mutational analyses of multiple target genes in histologically heterogeneous gastric cancer with microsatellite instability.

It has been recognized that gastric cancer often shows histological heterogeneity in a single tumor. Although microsatellite instability (MSI) has been reported in gastric cancer, the significance of genomic instability in gastric cancers with histological heterogeneity within a single tumor has never been addressed. We investigated MSI at 8 microsatellite loci in 40 normal/tumor DNA pairs from 20 gastric cancers with histological heterogeneity. Six of 20 patients (10 DNAs of 40 tumor DNAs) had severe MSI in more than 3 loci. Four of the MSI-positive cases had frameshift mutations in the poly(A)10 tract of the TGF beta RII gene. This mutation was found only in the MSI-positive component in the 2 cases (cases 4 and 5) in which only 1 component exhibited MSI. The other 4 cases demonstrated homozygous or heteroclonal mutations (1 and 2 base deletions) in the poly(A)8 tract of the hMSH3 gene; no mutation was detected in the poly(C)8 tract of the hMSH6 gene in any of the MSI-positive cases. The profile of alterations in multiple targets was different between the 2 components in most of the cases (5/6). These findings suggest that mismatch repair deficiency in MSI-positive tumors causes multiple gene inactivations through frameshift mutations in short repetitive sequences in a heterogeneous way within a histologically heterogeneous tumor.

Stage-dependent evaluation of microsatellite instability in gastric carcinoma with familial clustering.

Familial clustering of gastric cancer is probably caused by multifactorial processes, both environmental and genetic. In this report, the incidence of microsatellite instability (MSI) in 31 cases of gastric cancer in Japanese (33 lesions) with familial clustering (two or more gastric cancers within second-degree relatives) was compared to MSI in Japanese cases without a family of any cancer in age ( +/- 10 years)-, stage-, and histological subtype-matched case-control study. Although the difference noted was not significant, we noted a strong trend for MSI at any of up to seven loci of CA repeats to occur more frequently in the patients with a family history of gastric than in the control patients in early cancer (intramucosal and submucosal), whereas the prevalence of MSI was similar in both groups in more advanced cases, in which the tumor invaded beyond the proper muscle layer of the gastric wall. Because the contribution of a family history of gastric cancer to MSI apparently differs in early and advanced gastric cancer, interpretation of MSI in familial gastric cancer cases published previously require reevaluation in terms of stage and proper controls. An acquisition of CA repeat alterations in the early stage rather than in the late stage of gastric carcinogenesis may have in common etiological factors, at least in some cases, with the familial clustering of gastric cancer.

Morphological analysis of renal cell culture models of calcium phosphate stone formation.

Cell culture models of calcium phosphate renal stone formation were established using the MDCK cell line. Renal microliths were detected within pseudocysts in three-dimensional soft agar cultures, and were also observed in the basal region of cells lining the cell sheet, and immediately beneath domes or blisters in monolayers and collagen gel cultures. Light and scanning electron microscopy indicated that these microliths had a similar lamellated and spherical appearance to those in humans. These microliths were first detected microscopically after 21 days of culture, and were found to be composed of calcium phosphate by X-ray and micro-infrared spectroscopic analyses. These culture models may provide a powerful new tool to study the pathogenesis of renal stone diseases and/or calcium phosphate stone formation in humans and animals.

A very large villous adenoma with an adjacent cancer of the rectum: an informative case for testing the proposed molecular basis of colorectal tumorigenesis.

It is currently accepted that colorectal tumorigenesis results from accumulation of multiple mutations in certain genes. This concept prompted us to search for possible mutations in the APC, k-ras, and p53 genes in an advanced cancer coexisting with a large villous adenoma of the rectum in a 54-year-old patient with no family history of colorectal cancer. Genomic DNA extracted from multiple subregions of the tumor and surrounding normal mucosa was studied by polymerase chain reaction (PCR) followed by single-strand conformation polymorphism (SSCP) analysis and direct sequencing. Both the adenoma and carcinoma had abnormal PCR-SSCP for APC (exon 11) and k-ras, irrespective of the location within the tumors. However, p53 abnormality (exon 7) was detected only in samples taken from the carcinoma. Subsequent sequencing revealed a TTG to TAG mutation at codon 479 of APC, a GGT to GAT mutation at codon 12 of k-ras in both the adenoma and carcinoma, and a CGG to TGG mutation at codon 248 of p53 (exon 7) in the carcinoma. These findings were in accord with the current concept of colorectal tumor progression whereby genetic alteration of APC and k-ras occurs relatively early while that of p53 is rather late and is possibly a decisive event in relation to malignancy.

Nonpolypoid adenomas and adenocarcinomas found in background mucosa of surgically resected colons.

BACKGROUND: Nonpolypoid (depressed or flat) neoplasias are rarely seen in the colon and rectum. We previously reported their histogenesis and characteristics in patients with familial adenomatous polyposis (FAP), but their development in patients without FAP has not been studied systematically. METHODS: Three hundred specimens of large intestinal mucosa surgically resected from patients with cancers or other diseases, excluding FAP, were examined with a dissecting microscope. The morphologic types, sizes, locations, and frequencies of detectable colorectal neoplasias, and their histologic features, were analyzed. RESULTS: A total of 297 adenomas (240 polypoid, 32 flat, and 25 depressed type) were obtained. Nonpolypoid adenomas were most frequently found in the transverse and descending colon. Almost all depressed adenomas (24 of 25; 96%) were less than 3 mm in greatest dimension and almost all flat adenomas (31 of 32; 96.9%) were less than 3.5 mm in greatest dimension. Three minute, nonpolypoid adenocarcinomas (mean size, 2.6 mm; range, 2.4-2.9 mm) were also detected, two of them already invaded the submucosal layer. CONCLUSIONS: Minute nonpolypoid type adenomas may be present in the background mucosa of patients without FAP. This study suggests that even minute nonpolypoid adenocarcinomas have an increased potential for endophytic growth.

Synchronous lymphoma and adenocarcinoma occurring as a collision tumor in the stomach: report of a case.

We report herein the rare case of a 71-year-old man who was initially operated on under the diagnosis of advanced gastric cancer, but was subsequently found to have synchronous lymphoma and early adenocarcinoma of the stomach, confirmed by postoperative pathological examination. The patient had a history of lymphoma of the left tonsil, and histologically the gastric lymphoma was observed to be of the non-Hodgkin's, diffuse, large-cell type. Conversely, the gastric cancer was early well-differentiated tubular adenocarcinoma of type 0-IIa, according to the Japan Gastroenterological Endoscopy Society classification. The two tumors had collided at the fornix. The relationship between these two tumors is analyzed and the most appropriate methods of diagnosis and treatment are discussed.

Localization of Menkes gene expression in the mouse brain; its association with neurological manifestations in Menkes model mice.

Menkes gene (Mc1 or MNK, encoding putative copper-transporting ATPase) expression was investigated and compared in normal and macular mutant mouse brain. Northern blot analysis showed a distinct 8.3-kb transcript and no obvious difference in size or extent in normal mice and macular mutants on postnatal days 0, 4, 7, 10 or 13. In situ hybridization revealed that certain specific populations of cells in the brain express Menkes mRNA, and that their localization in normal and mutant mice did not differ and was conserved on days 4, 10 and 13. The most intense hybridization signals were observed in the hippocampal CA1 region and dentate gyrus, the olfactory bulb nuclei, the cerebellar granular cell layer, the choroid plexus and the ependyma, with less intense signals in the hippocampal CA3 region and cerebellar Purkinje cells. In addition, necrotic neuronal cell death was predominantly observed in the CA3 region and the Purkinje cells of macular mice after postnatal day 10. The finding that the regions that had lower expression level of Menkes mRNA corresponded to those showing neuronal necrosis suggests that the Menkes gene may be responsible for the neuronal degeneration in some specific portions of the brain and clinical manifestations in this mutant.

Frequent co-occurrence of mutator phenotype in synchronous, independent multiple cancers of the stomach.

The prevalence of multiple independent primary cancer of the stomach is high in Japanese. We hypothesized that individuals with multiple, independent gastric cancers might have a greater genetic susceptibility than persons with solitary gastric cancer at the time of diagnosis. We therefore determined the frequency of mutator phenotypes in 20 persons with independent multiple gastric cancers and 42 persons with solitary primary lesions. The mutator phenotype was determined by examining dinucleotide CA repeats at the microsatellite loci D2S136 (chromosome 2), MSX2 (chromosome 5q34), D5S82 (chromosome 5q14-21) and TP53 (chromosome 17p13.1). Although there were no significant differences between the clinical and pathological features (stage or histopathological subtype) of the two groups, the prevalence of any one microsatellite instability in patients with multiple gastric cancer was greater (65% versus 24%; P = 0.003) than in those with solitary gastric cancer. The prevalence of co-occurrence of mutator phenotype in synchronous lesions was greater than expected based on their frequency in solitary gastric cancer (12% versus 9% x 9%). Persons with advanced-stage multiple primary lesions were more likely to exhibit the mutator phenotype (P = 0.10). These findings indicate that individual predisposition for qualitative or quantitative defects in DNA repair systems significantly contribute to the simultaneous occurrence of gastric cancer in Japanese.

Histological classification of the neoplastic changes arising in ulcerative colitis: a new proposal in Japan.

Patients with total ulcerative colitis with a longstanding course of the disease have a high risk of developing colorectal carcinoma. Colonoscopic surveillance to detect precancerous tissue and/or cancer in these patients has been carried out in countries with a high incidence of ulcerative colitis. Riddell's classification has been widely used for the interpretation of biopsy specimens obtained from the colonoscopic surveillance. In Japan, however, there are problems in accepting Riddell's classification, mainly because the intramucosal carcinomas diagnosed by Japanese histopathologists are included in the category of high-grade dysplasia in Riddell's classification. Based on the results of a meticulous slide review carried out by seven histopathologists in this study, a new classification is proposed: UC-I, inflammatory change; UC-II, indefinite; UC-IIa, probably inflammatory; UC-IIb, probably neoplastic; UC-III, neoplastic but not carcinomatous; and UC-IV, carcinoma. Intramucosal carcinomas is included in the category UC-IV. We consider that the diagnosis of intramucosal carcinoma is to be made when there is a high grade of cytological and structural atypia consistent with carcinoma. Interobserver and intraobserver variability with this classification was acceptable. We believe this new classification will be widely use in cancer surveillance in ulcerative colitis in Japan.

Correlation of detectability of hepatitis C virus genome in saliva of elderly Japanese symptomatic HCV carriers with their hepatic function.

The hepatitis C virus (HCV) genome was sought in the saliva of 76 chronic HCV carriers (mean age nearly 60 years) in a rural Japanese town, who had high serum titers of c-100 and anti-core second generation antibodies. In 27 samples (27 cases, 36%), the HCV-RNA genome was detected by the reverse transcriptase - polymerase chain reaction with either of two sets of primers covering two regions of the HCV genome: the 5'noncoding region and the region encompassing the putative envelope (E1). Transaminase values at the time of sampling were higher in the patients with than in those without detectable HCV RNA in saliva (p = 0.04 for alanine aminotransferase, p = 0.04 for aspartate aminotransferase; Wilcoxon test). The prevalence of the positivity was higher by 5'noncoding primers (14/59 vs. 15/68). Our data show that the severity and duration of hepatic dysfunction influence the detectability of the HCV genome in the saliva. This has been a controversial point among investigators.

Immunocytochemical study of microvilli in a gastric carcinoma-derived cell line.

To study the structural components of microvilli of the KATO-III cell, we used anti-villin, -ezrin, and anti-MVM (microvillous membrane prepared against mouse intestinal microvilli) antibodies. Villin and ezrin cross-link actin bundles of microvilli such as those in the small intestine and renal proximal cells. Electromicroscopically, the cytoskeletal core of microvilli of the KATO-III cell was constituted of actin-filament bundles. The anti-villin antibody but not anti-ezrin antibody reacted with the KATO-III cell as demonstrated by FITC-immunofluorescence and PAP-staining. Anti-villin, anti-MVM, but not anti-ezrin antibody, reacted with the KATO-III cell surface and with intracellular materials. Western blot analysis using anti-villin and anti-MVM antibodies revealed proteins of approximately 95 kDa (villin), and 15 kDa in the microsomal membrane fractions of KATO-III cells, respectively. Immunocytochemical and confocal laser microscopic studies showed that the cell-surface and the intracellular microcysts of KATO-III cells were preferentially decorated by anti-villin and anti-MVM antibodies. These data suggested that some actin-binding proteins, such as villin, were localized at the cell surface and on some of the intracellular cytoplasmic structures of the KATO-III cell.

Intrasellar neuronal choristoma associated with growth hormone-producing pituitary adenoma containing amyloid deposits.

The histological, immunocytochemical, and ultrastructural features of an intrasellar neuronal choristoma associated with pituitary growth hormone (GH)-producing adenoma are reported. Immunohistochemistry studies and electron microscopy examination showed the adenoma cells to be positive for GH but negative for prolactin, and the neurons of the choristoma to have GH-releasing factor (GRF) neurosecretory activity. The adenoma also had many amyloid deposits in its extracellular space immunoreactive to GRF. This is the first report of the tumor containing amyloid deposits.

Monoclonality of normal human colonic crypts.

The monoclonality of human colonic crypts was demonstrated by human androgen receptor (HUMARA) gene assay following application of the crypt isolation method. DNA was extracted from an isolated single crypt, Hpa II digestion was performed before polymerase chain reaction (PCR) by primers spanning the HUMARA exon 1 region. The PCR product of a single crypt clearly showed allelic exclusion based on methylation status, while PCR product from a mixture of 40 crypts or colonic mucosa as a whole that included epitheliums and interstitial connective tissue had two bands. This method will facilitate the non-isotopic analysis not only of tumor clonality, but also of the normal structures derived from a single progenitor cell.

[Immunohistochemical distribution of p53 and Ki-67 in 2 cases of colorectal carcinoma occurring in ulcerative colitis].

We studied immunohistochemically the distribution of p53 overexpression and Ki-67 as a marker of cell proliferation, in 2 cases of advanced colorectal carcinomas occurring in UC, in comparison with histopathological features such as carcinoma and dysplasia. One is a case of 4 independent colorectal carcinomas surrounded by widespread dysplasia, and the other is a case of solitary rectal carcinoma. In these 2 cases, formalin-fixed paraffin-embedded tissues covering all of the resected specimens were examined for p53 and Ki-67 immunoreactivity using microwaving technique. p53 was negative in normal mucosa and inflammative mucosa without dysplasia. p53 was strongly positive in cancerous lesions except one lesion, and various degrees of dysplasia surrounding these lesions also showed p53 positive. The numbers of p53 and Ki-67 positive cells were higher in severe dysplasia than in mild dysplasia. Some areas of the dysplastic mucosa histologically represented "hyperplastic pattern of villous feature." In these areas p53 positive cells were aggregated in the basal part of the villous crypt, and the number of Ki-67 positive cells per gland was larger than in normal gland. Our examination covering the whole mucosa revealed: 1) p53 and Ki-67 are useful diagnostic markers for grading the degree of dysplasia. 2) Positivity of immunoreactive p53 in dysplasia seems to be consistent with that in cancers occurring in the surrounding dysplastic area in most of our cases.

Efficient and specific induction of esophageal tumors in rats by precursors of N-nitrososarcosine ethyl ester.

Cancers and precancerous lesions of the esophagus were efficiently induced in rats by the simulation of a clinico-epidemiological setting; that is, the administration of precursors of nitrosamine. Six week old non-inbred male Wistar rats were given 2g/kg bodyweight of sarcosine ethyl ester hydrochloride (SEEH) and concurrently 0.3g/kg bodyweight of sodium nitrite (NaNO2), precursors of N-nitrososarcosine ethyl ester (NSEE), in 2% sucrose as drinking water. Group 1 received the precursors twice a week for 6 weeks followed by 8 weeks observation, and group 2, once every 3 days for 7 weeks followed by 26 weeks observation. At the end of treatment, no tumor had developed in the esophagus of rats in group 1, but the [3H]-thymidine labeling indices in both basal and superficial layer cells were higher than in the control group. On subsequent observation, papillomas appeared in group 1 (33.3%), and carcinomas in group 2 (33.3%), within 4 weeks. The tumors induced in group 1 were mostly papillomas and rarely carcinomas. When the observation was prolonged in group 2, 100% of the animals had cancer in week 20. The pathological changes of the lesions paralleled the sequential development of human squamous cell carcinoma of the esophagus. Our system has the advantages in that papillomas and cancers can be induced in rats in a short time and the agents used are less toxic than preformed nitrosamines administered previously by gastric intubation. It would serve as a useful experimental tool to study premalignant lesions and cancers of the esophagus.

A case of triple early gastric cancer in the remnant stomach.

A 63-yr-old man, who had undergone distal gastrectomy and gastrojejunostomy (Billroth II method) 32 yr previously for duodenal ulcer, was admitted with suspected gastric remnant cancer. An upper gastrointestinal series and endoscopy revealed a protruding lesion at the stoma of the remnant stomach. Total gastrectomy with resection of the adjacent jejunum was performed. Histological examination demonstrated two well-differentiated adenocarcinomas (a mixed type I and IIc lesion with submucosal invasion and a type IIa lesion with intramucosal invasion) and a type IIc mucocellular carcinoma located in the mucosa. Gastritis cystica polyposa also was observed in the remnant stomach. The combination of three early gastric cancers and gastritis cystica polyposa suggests that the mucosa of the remnant stomach had a high malignant potential. The patient has survived without recurrence for 5 yr since the operation.

Role of apoptosis in modulation of the growth of human colorectal tubular and villous adenomas.

To estimate the effect of cell proliferation and deletion on the growth of the human colorectal adenoma, 27 tubular adenomas and eight villous adenomas were examined. Tubular adenomas were categorized into three grades of cellular atypia: mild, moderate, and severe. Villous adenomas were given a single grade. Morphological characteristics of apoptosis (nuclear condensation and budding) were used to quantify an apoptotic index, AI (percentage of apoptotic cells in viable adenomatous cells). The apoptotic cells were found mainly among the basal site of the adenomatous tubules. The AIs of tubular adenomas with mild, moderate, and severe grades of atypia were 3.5, 5.7 and 8.8 per cent, respectively. The AI of villous adenomas was 1.8 per cent, which was significantly lower than that of tubular adenomas. The mitotic indices, MIs (percentage of mitotic cells in viable adenomatous cells) of tubular adenomas were 0.41 per cent (mild), 0.58 per cent (moderate), and 0.83 per cent (severe), and for villous adenomas the MI was 0.38 per cent. There was a close positive relationship between the AI and MI of tubular adenomas, which paralleled the grade of atypia. These results indicate that both cell proliferation and death were more frequent in adenomas with severe atypia than in adenomas with mild atypia. Moreover, the significantly lower AI of villous adenomas, known to develop into large tumours when compared with tubular adenomas, suggests that reduced apoptoses may lead to a shift in tissue kinetics towards expansive growth.