Pharmacist's attitudes towards dispensing errors: their causes and prevention

OBJECTIVE

To assess the attitudes of pharmacists towards the issue of dispensing errors.

METHOD

A postal survey was undertaken among all Tasmanian-registered pharmacists residing in Australia. The anonymous questionnaire sought opinions on whether the risk of dispensing errors and the actual numbers of errors are increasing, the major factors contributing to the occurrence of dispensing errors, factors that can best minimize the risk of dispensing errors, the number of prescription items that one pharmacist can safely dispense in a day and whether Australia should have a regulatory maximum dispensing load, and an estimation of the number of recent errors at the pharmacist's workplace.

RESULTS

Completed questionnaires were received from 209 pharmacists (50% response rate). Most pharmacists (82%) believed that the risk of dispensing errors is increasing. The principal contributing factors nominated were: high prescription volumes, pharmacist fatigue, pharmacist overwork, interruptions to dispensing, and similar or confusing drug names. The main factors identified as being important in reducing the risk of dispensing errors were: having mechanisms for checking dispensing procedures, having a systematic dispensing workflow, checking the original prescription (duplicate) when dispensing repeats, improving the packaging and labelling of drug products, having drug names that are distinctive, counselling patients at the time of supply, keeping one's knowledge of drugs up-to-date, avoiding interruptions, reducing workloads on pharmacists, improving doctors' handwriting, and privacy when counselling patients. Most pharmacists (72%) stated that they were aware of dispensing errors that had left the pharmacy undetected, in their place of practice during the past 6 months. The median number of such dispensing errors that they were aware of was three. A median of 150 was nominated as the maximum number of prescription items that can be safely dispensed per 9-h day (i.e. 17 items per hour) by or in the presence of one pharmacist. Most pharmacists (58%) stated that there should be a regulatory guideline for the safe dispensing load in Australia.

CONCLUSION

Dispensing errors are occurring in numbers well above reports to regulatory authorities or professional indemnity insurance companies, and seem to be accepted as part of practice. High prescription volumes, pharmacist fatigue and overwork appear to be important factors. The profession needs to be proactive and standards must be set appropriately high (i.e. zero error tolerance).

Disseminated cystic lymphangiomatosis presenting with acute abdomen: report of a case and review of the literature

Lymphangioma is an uncommon tumor. Lymphangiomatosis, a benign tumor consisting of a cluster of dilated lymphatic channels, is very unusual. Most lymphangiomatoses are found in the neck and head area. Less than 5% are diagnosed intraabdominally and they are very infrequently encountered in the retroperitoneal area. Herein, we report a rare case of a 32 year-old woman who had disseminated intra-abdominal and retroperitoneal cystic lymphangiomatosis, which presented as acute abdomen. She received exploratory laparotomy due to the suspicion of malignancy, which was finally confirmed as cystic lymphangiomatosis. The clinical manifestations, imaging features, and management of this patient are discussed and compared with previous literature.

Helicobacter pylori stool antigen (HpSA) test--a simple, accurate and non-invasive test for detection of Helicobacter pylori infection

BACKGROUND/AIMS

To access the reliability of a newly developed test, the Helicobacter pylori (H. pylori) stool antigen (HpSA) test was used for detection of H. pylori infection.

METHODOLOGY

Stool specimens were collected from 33 consecutive patients (19 males and 14 females, age range: 16-73 years, mean: 49 years) who received upper gastrointestinal endoscopic examination for gastrointestinal symptoms. The H. pylori status was evaluated based on six different tests: culture, histology, biopsy urease test, 13C-urea breath test (13C-UBT), serology, and HpSA test. A commercial kit using an enzyme-linked immunosorbent assay examined HpSA in the stool. H. pylori status was defined as positive when the culture was positive or concordance of three of the other four tests (histology, biopsy urease test, 13C-UBT, and serology) was positive.

RESULTS

Twenty patients were diagnosed as H. pylori-positive. The HpSA test was positive in 19 patients and negative in 14 patients. The sensitivity and specificity were 95.0% and 100%, respectively. The overall accuracy rate was 96.3%.

CONCLUSIONS

The HpSA test is a new, simple, non-invasive method for accurate diagnosis of H. pylori infection.

Peroxisome proliferator-activated receptors gamma and alpha mediate in vivo regulation of uncoupling protein (UCP-1, UCP-2, UCP-3) gene expression

A role for peroxisome proliferator-activated receptors, PPAR gamma and PPAR alpha, as regulators of energy homeostasis and lipid metabolism, has been suggested. Recently, three distinct uncoupling protein isoforms, UCP-1, UCP-2, and UCP-3, have also been identified and implicated as mediators of thermogenesis. Here, we examined whether in vivo PPAR gamma or PPAR alpha activation regulates the expression of all three UCP isoforms. Rats or lean and db/db mice were treated with PPAR gamma [thiazolidinedione (TZD)] or PPAR alpha (WY-14643) agonists, followed by measurement of messenger RNAs (mRNAs) for UCP-1, UCP-2, and UCP-3 in selected tissues where they are expressed. TZD treatment (AD 5075 at 5 mg/kg x day) of rats (14 days) increased brown adipose tissue (BAT) depot size and induced the expression of each UCP mRNA (3x control levels for UCP-1 and UCP-2, 2.5x control for UCP-3). In contrast, UCP-2 and UCP-3 mRNA levels were not affected in white adipose tissue or skeletal muscle. Chronic (30 days) low-dose (0.3 mg/kg x day) TZD treatment induced UCP-1 mRNA and protein in BAT (2.5x control). In contrast, chronic TZD treatment (30 mg/kg x day) suppressed UCP-1 mRNA (>80%) and protein (50%) expression in BAT. This was associated with further induction of UCP-2 expression (>10-fold) and an increase in the size of lipid vacuoles, a decrease in the number of lipid vacuoles in each adipocyte, and an increase in the size of the adipocytes. TZD treatment of db/db mice (BRL 49653 at 10 mg/kg x day for 10 days) also induced UCP-1 and UCP-3 (but not UCP-2) expression in BAT. PPAR alpha is present in BAT, as well as liver. Treatment of rats or db/db mice with WY-14643 did not affect expression of UCP-1, -2, or -3 in BAT. Hepatic UCP-2 mRNA was increased (4x control level) in db/db and lean mice, although this effect was not observed in rats. Thus, in vivo PPAR gamma activation can induce expression of UCP-1, -2, and -3 in BAT; whereas chronic-intense PPAR gamma activation may cause BAT to assume white adipose tissue-like phenotype with increased UCP-2 levels. PPAR alpha activation in mice is sufficient to induce liver UCP-2 expression.

Timing and necessity of endoscopy in AIDS patients with dysphagia or odynophagia

BACKGROUND/AIMS

Dysphagia and odynophagia are common problems with significant morbidity in acquired immunodeficiency syndrome (AIDS) patients. Endoscopy in AIDS patients with esophageal symptoms is valuable for diagnosis, but the timing and necessity of routine endoscopy remains controversial.

METHODOLOGY

We retrospectively studied 40 AIDS patients undergoing upper gastrointestinal endoscopy. Among them, 25 patients were enroled with dysphagia and/or odynophagia and were put on empirical fluconazole treatment before endoscopic evaluation.

RESULTS

Fourteen (56%) of 25 patients improved after fluconazole treatment, while 11 patients had persistent symptoms. Among the 14 patients with symptomatic improvement, 7 were found to have esophageal candidiasis which improved after continuation of fluconazole for 1-2 more weeks. The other 7 patients had a normal endoscopic appearance. In contrast, among 11 patients with persistent symptoms, there were 3 patients with azole-resistant candidiasis, 3 with cytomegalovirus esophagitis, 1 with herpes simplex virus esophagitis with candidiasis, 1 with Kaposi's sarcoma, and 3 with idiopathic esophageal ulcer. They were successfully treated with Amphotericin B, Ganciclovir, Acyclovior, and oral steroids, except for the patient with Kaposi's sarcoma.

CONCLUSIONS

Routine endoscopy may not necessarily be indicated in every AIDS patient with dysphagia or odynophagia. Empirical fluconazole treatment can improve symptoms in 50% of patients. It is only indicated when patients have persistent symptoms after empirical treatment. With endoscopic examination, etiologic agents other than common candidiasis can be determined and the patients can thus be put on specific treatment.

Helicobacter pylori-seronegative gastric carcinoma: a subset of gastric carcinoma with distinct clinicopathologic features

BACKGROUND/AIMS

The frequent association of gastric atrophy and intestinal metaplasia in gastric cancer (GC) might preclude serologic detection of Helicobacter pylori (H. pylori) infection in GC. By using polymerase chain reaction (PCR) for detection, we would like to determine whether there exists a subset of genuinely H. pylori-negative GC patients, and whether they have distinct clinicopathologic features or not.

METHODOLOGY

IgG antibodies against H. pylori were determined by ELISA in sera, and H. pylori DNA was detected by PCR in resected gastric specimens from 160 GC patients. Clinicopathologic characteristics were then compared among group A: seropositive, group B: seronegative but PCR-positive, and group C: seronegative and PCR-negative.

RESULTS

Among 160 patients, 105 (65.6%) were classified as group A, 25 (15.6%) as group B, and 30 (18.8%) as group C. Group B patients were older and had more infiltrative tumor growth than group A. Group C had a significantly higher frequency of female predominance, and their cancers were of a more cardiac location and of the diffuse histologic subtype than those of groups A and B.

CONCLUSIONS

A significant portion (15.6%) was negative to ELISA but positive to PCR, suggesting that older ages and infiltrative tumor growth might preclude serologic detection of H. pylori infection by impairing humoral responses. Although the majority (81.2%) has a strong association with H. pylori infection, an H. pylori-negative subset indeed exists and has distinct clinicopathologic features, supporting that causes other than H. pylori infection are involved in GC carcinogenesis.

Anomalous pancreaticobiliary ductal union--an etiologic association of gallbladder cancer and adenomyomatosis

BACKGROUND/AIMS

Anomalous pancreaticobiliary ductal union (APBDU) has been proposed as a risk factor of gallbladder cancer. To clarify the frequency and the subtype distribution of APBDU in patients with gallbladder cancer and adenomyomatosis, a retrospective study was performed.

METHODOLOGY

The radiograms of endoscopic retrograde cholangiopancreaticography of 680 patients with well-documented biliary and pancreatic ducts from April 1992 to November 1996 were reviewed. The length of the common channel and insertion of the pancreatic duct and the bile duct were identified and recorded.

RESULTS

Gallbladder cancer and adenomyomatosis were identified in 8 and 12 patients, respectively. Patients with gallbladder cancer were significantly older (mean age: 66.5 years, p<0.01) than those with gallbladder adenomyomatosis (mean age: 42.7 years). APBDU was noted in 59 (8.7%) of 680 cases with complete pancreaticobiliary radiograms. Among them, 5 of 8 patients with gallbladder cancer coexisted with APBDU. Four (80%) belonged to the P-B type. Six of 12 patients with gallbladder adenomyomatosis had APBDU. Five (83.3%) belonged to P-B type.

CONCLUSIONS

Patients with gallbladder cancer and adenomyomatosis were frequently associated with APBDU. The close relationship and similar distribution of the P-B type of APBDU in both diseases suggest an etiologic association in various gallbladder diseases.

Gastric leiomyosarcoma mimicking a cystic tumor at the pancreatic tail--one case report

A 73 year-old female patient suffered from anemia and a palpable abdominal mass. Abdominal ultrasonography and magnetic resonance imaging revealed a lesion with papillary excrescences at the pancreatic tail. Endoscopic retrograde cholangiopancreatography showed a normal pancreatic duct, but a small submucosal tumor was found in the stomach incidentally. Laparotomy disclosed an exophytic tumor arising from the submucosal layer of the stomach. Pathology revealed a gastric leiomyosarcoma with remarkable liquefaction and cystic change. Gastric leiomyosarcoma can be so necrotic as to be mistaken for a cystic tumor. It is critically important to differentiate the peripancreatic cystic lesion because the treatment strategy is totally different.

Cyclosporin inhibits nitric oxide production in medullary ascending limb cultured cells

BACKGROUND

Nitric oxide (NO) has been shown to play a role in cyclosporin (CsA) nephrotoxicity, but its mechanism of action is still unclear. As inducible NO synthase (iNOS) mRNA has been found to be expressed in rat medullary thick ascending limb (mTAL) cells, we investigated the effects of CsA on NO production in a model of mouse cultured mTAL cells.

MATERIALS AND METHODS

The experiments were carried out on sub-cultured cells derived from isolated mTAL microdissected from the kidney of C57BL/6 mice. The identification of the iNOS mRNA in mTAL microdissected segment and cultured cell was confirmed by RT PCR and RsaI digestion. Nitrite (NO2) released by mTAL cells was determined using the modified Griess reagent method and taken as an index of nitric oxide production. The cultured cells were treated with various concentrations of CsA and different signal transduction regulators to assess the effect and possible pathway(s) of action of CsA on NO production in mTAL cells.

RESULTS

The basal production of NO by mTAL cells increased by 1.8-fold following incubation with bacterial lipopolysaccaride (LPS). Both aminoguanidine and L-NAME inhibited NO production. CsA (10-300 ng/ml) also inhibited NO production in a dose-dependent manner and prevented its increase induced by LPS. Phorbol 12-myristate 13-acetate (PMA), a PKC stimulator, enhanced slightly the production of NO under basal conditions and prevented the inhibitory action of CsA on NO production. These results suggest that the NO secreted by mouse cultured mTAL cells is dependent on the PKC pathway.

CONCLUSION

These results show that CsA may down-regulate the production of NO by cultured mTAL cells expressing iNOS mRNA and that the PKC pathway is involved in this process.

Helicobacter pylori infection and age on the development of intestinal metaplasia--a multiple logistic regression analysis

BACKGROUND/AIMS

Both intestinal metaplasia (IM) and Helicobacter pylori (H. pylori) infection have been linked to gastric carcinogenesis in an age-dependent manner. However, their relationship remains ill defined, especially with respect to age.

METHODOLOGY

Three hundred and two asymptomatic subjects (167 males and 135 females; mean age 44.3+/-11.1 years) underwent complete endoscopic examination and biopsy at the antrum and the corpus. H. pylori infection was diagnosed according to histopathology and serology, while IM was determined by histopathology.

RESULTS

Eighty-four patients (27.8%) had IM, while 185 patients (61.3%) were seropositive to H. pylori. The frequency of IM was higher in patients with gastric ulcer (9/14, 64.3%) than in those with minimal change (68/229, 29.7%) or duodenal ulcer (7/59, 11.9%), both p<0.01. Patients with IM had a higher mean age (49.5+/-14.1 vs. 42.3+/-9.0, p<0.01) and a higher H. pylori prevalence than those without IM (61/84, 72.6% vs. 124/218, 56.9%, p<0.01). The concordance rate of H. pylori infection between histopathologic and serologic diagnosis was lower in patients with IM (67/84, 79.8%) than those without (196/218, 89.9%, p<0.05). Using logistic regression analyses, the development of IM was noted to be independently related to both H. pylori infection (odds ratio=1.97, 95% confidence interval: 1.1(3.53)) and age (odds ratio = 1.93, 95% confidence interval: 1.51(2.47)).

CONCLUSIONS

These data suggest that age and H. pylori infection are independent risk factors for the development of IM. Furthermore, H. pylori infection may have been underestimated in patients with IM because of the use of a single method of detection.

Overexpression of p53 in different subtypes of intestinal metaplasia and gastric cancer

p53 immunostaining was evaluated in cancerous epithelia and adjacent intestinal metaplasia of 135 gastric cancer specimens. The differential p53 overexpression in different subtypes of intestinal metaplasia and gastric cancer suggests that type III intestinal metaplasia is the commonest lesion in dysplasia-carcinoma transition, particularly in the intestinal type of gastric cancer.

Urinary endothelin-1 in patients with renal disease

The purpose of this study was to investigate the usefulness of urinary endothelin-1 (ET-1) as a marker of renal disease. We measured urinary excretion of ET-1 in 28 patients with glomerulonephritis (GN), 22 patients with chronic renal failure (CRF), 40 patients with end-stage renal disease (ESRD), and 17 healthy volunteers. There was no significant difference in 24-hour urinary ET-1 excretion among the four groups (mean +/- SEM, 0.49 +/- 0.22 ng in controls, 0.79 +/- 0.37 ng in GN patients, 0.39 +/- 0.18 ng in CRF patients, and 0.28 +/- 0.11 ng in ESRD patients). The 24-hour urinary excretion of ET-1 in patients with GN or CRF showed significant correlation with the urinary excretion of sodium (r = 0.27, p < 0.05). The 24-hour urinary beta 2-microglobulin (beta 2M) excretion in patients with CRF (18.4 +/- 2.6 mg) or ESRD (9.7 +/- 1.1 mg) was significantly higher than in normal control subjects (0.23 +/- 0.11 mg). Serum creatinine concentration was positively correlated with the 24-hour urinary excretion of beta 2M in patients with GN or CRF (r = 0.50, p < 0.001). These findings indicate that urinary ET-1 is not as good a marker of renal disease as urinary beta 2M. However, it may be responsible for urinary sodium excretion in patients with GN or CRF.

Vaccine effect of granulocyte-macrophage colony-stimulating factor or CD80 gene-transduced murine hematopoietic tumor cells and their cooperative enhancement of antitumor immunity

To develop immunogene therapy targeting minimal residual hematopoietic tumor cells in patients, we transduced murine GM-CSF or CD80 gene into murine WEHI 3B myelomonocytic leukemia and EL-4 thymic lymphoma cells using retroviral vectors and evaluated their effects on inducing antitumor responses in syngeneic host mice. Subcutaneously injected GM-CSF- and CD80 gene-transduced WEHI 3B (GMCSF/WEHI/3.2 or CD80/WEHI/1.8, respectively) cells lost their original tumorigenicity in immunocompetent syngeneic mice. Results from tumor inoculation experiments using athymic nude mice suggested that the rejection of GMCSF/WEHI/3.2 in immunocompetent mice depended fully on T cells and that of CD80/WEHI 1.8 depended partly on T cells and partly on NK cells. In both WEHI 3B and EL-4 models, irradiated GM-CSF gene-transduced cells provided strong immuno-protection against wild-type cells, but irradiated CD80 gene-transduced cells did not. A remarkably high cooperative effect was obtained when irradiated GMCSF/EL-4 and CD80/EL-4 were inoculated together. These results suggested that the tumor vaccine effect is efficiently enhanced by GM-CSF gene transduction and CD80 gene transduction induces some protective antitumor immunity in co-operation with GM-CSF gene transduction.

Immunochemical characterization of Na+/H+ exchanger isoform NHE4

Mammalian Na+/H+ exchangers (NHEs) are a family of transport proteins (NHE1-NHE5). To date, the cellular and subcellular localization of NHE4 has not been characterized using immunochemical techniques. We purified a fusion protein containing a portion of rat NHE4 (amino acids 565-675) to use as immunogen. A monoclonal antibody (11H11) was selected by ELISA. It reacted specifically with both the fusion protein and to a 60- to 65-kDa polypeptide expressed in NHE4-transfected LAP1 cells. By Western blot analysis, NHE4 was identified as a 65- to 70-kDa protein that was expressed most abundantly in stomach and in multiple additional epithelial and nonepithelial rat tissues including skeletal muscle, heart, kidney, uterus, and liver. Subcellular localization of NHE4 in the kidney was evaluated by Western blot analysis of membrane fractions isolated by Percoll gradient centrifugation. NHE4 was found to cofractionate with the basolateral markers NHE1 and Na+-K+-ATPase rather than the luminal marker gamma-glutamyl transferase. In stomach, NHE4 was detected by immunoperoxidase labeling on the basolateral membrane of cells at the base of the gastric gland. We conclude that NHE4 is a 65- to 70-kDa protein with a broad tissue distribution. In two types of epithelial cells, kidney and stomach, NHE4 is localized to the basolateral membrane.

Overexpression of p53 predicts shorter survival in diffuse type gastric cancer

BACKGROUND

It has been suggested that p53 plays an important part in gastric carcinogenesis but the data remain inconclusive.

METHODS

Alteration of the tumour suppressor gene p53 was prospectively investigated by immunohistochemistry in 168 primary gastric cancers.

RESULTS

Positive staining, indicative of gene mutations, was detected in 34 tumours (20.2 per cent). No correlation was observed between expression of p53 and various clinicopathological factors, including age, sex, tumour site, gross type, tumour size, depth of invasion, lymph node metastases, distant metastases, and tumour node metastasis stage. However, p53 overexpression was different between intestinal and diffuse type gastric cancer. Survival analysis revealed a significant survival disadvantage of p53 expression in diffuse type gastric cancer (P=0.039) but not in the intestinal type. Multivariate analysis of all 168 patients revealed that independent predictors of recurrent disease included age, invasion depth and nodal involvement but not p53 expression.

CONCLUSION

The presence of p53 overexpression may identify a subset of more aggressive tumours with a poor prognosis in diffuse type gastric cancer.

Pancreaticobiliary diseases associated with anomalous pancreaticobiliary ductal union

BACKGROUND

Anomalous pancreaticobiliary ductal union (APBDU) is associated with different pancreaticobiliary diseases. The aim of this study is to clarify the frequency with which it occurs and its several subtypes in various pancreaticobiliary diseases.

METHODS

Radiograms of 1752 subjects who underwent endoscopic retrograde cholangiopancreatography were reviewed independently by two endoscopists. APBDU was diagnosed using recently accepted criteria and divided into B-P and P-B subtypes according to the insertion of biliary and pancreatic ducts.

RESULTS

Fifty-nine (8.7%) of 680 subjects with clearly visualized pancreaticobiliary radiograms had APBDU. APBDU was present in 93.8% of patients (15 of 16) with choledochal cyst, 62.5% (5 of 8) with gallbladder cancer, 33.3% (9 of 27) with common bile duct cancer, 50.0% (6 of 12) with gallbladder adenomyomatosis, 13.2% (7 of 53) with biliary pancreatitis, 3.4% (10 of 293) with cholelithiasis, 2.2% (2 of 89) with non-biliary pancreatitis, 2.1% (1 of 47) with hilar cholangiocarcinoma, 1.9% (1 of 54) with pancreatic cancer, and 10.2% (9 of 88) with other miscellaneous disorders. There were 25 patients (42.4%) with the B-P type and 34 patients (57.6%) with the P-B type of APBDU. Patients with choledochal cyst frequently had the B-P type, whereas gallbladder cancer, adenomyomatosis, or biliary pancreatitis frequently coexisted with the P-B type.

CONCLUSION

APBDU is relatively common in patients undergoing endoscopic retrograde cholangiopancreatography at our center. There are a variety of pancreaticobiliary diseases that are associated with APBDU. Its role in these conditions is uncertain and needs to be further delineated.

Pharmacologic agents inhibit rat mesangial cell proliferation and collagen synthesis

Prevention of the development of end-stage renal disease is one of the most promising areas of research in nephrology. Because mesangial cell proliferation and extracellular matrix accumulation have been regarded as antecedents of glomerulosclerosis, agents that can inhibit mesangial cell proliferation may have a potential to retard the progression of renal diseases. Therefore, we investigated several clinically available agents that might affect mesangial cell proliferation and collagen synthesis in male Sprague-Dawley rats. Cell proliferation was measured by the tetrazolium dye uptake method. Collagen synthesis was measured by 3H-proline incorporation into pepsin-resistant, salt-precipitated collagen. Intracellular cAMP levels were measured by enzyme immunoassay. Our results showed that hydralazine (82% inhibition at 10 micrograms/mL), ticlopidine (61% inhibition at 30 micrograms/mL), aminophylline (66% inhibition at 200 micrograms/mL), and nicametate (91% inhibition at 1 mg/mL) inhibited serum-stimulated rat mesangial cell (RMC) growth in a dose-dependent manner. Ticlopidine (43% inhibition at 30 mg/mL), aminophylline (52% inhibition at 200 mg/mL), and nicametate (35% inhibition at 1 mg/mL) inhibited collagen synthesis in confluent RMCs. Aminophylline may act through increasing intracellular cAMP levels (9.7 +/- 0.7 pmol/mg protein at 200 micrograms/mL of aminophylline vs 4.2 +/- 0.6 pmol/mg protein at control). These data suggest that aminophylline, ticlopidine, hydralazine, and nicametate can inhibit RMC proliferation and collagen synthesis.

An immunohistochemical study of E-cadherin expression with correlations to clinicopathological features in gastric cancer

BACKGROUND/AIMS

Reduced expression of E-cadherin leading to loss of cellular adhesion is crucial for cancer invasion and metastasis. The aim of this study is to investigate the role of E-cadherin in gastric tumorigenesis.

METHODOLOGY

Immunohistochemical expression of E-cadherin was analyzed and correlated with clinicopathological characteristics of 122 patients with gastric cancer.

RESULTS

Reduced E-cadherin expression was noted in 71 tumors (58.2%), while all normal epithelium showed a normal expression. Correlation of E-cadherin status to histological subtypes and growth patterns revealed a significantly higher frequency of reduced expression in diffuse type (46/60, 76.7%), advanced tumors (48/68, 70.6%) and stage III/IV (39/53, 73.6%) than that in intestinal type (25/62, 40.3%, p<0.0001), early tumors (23/54, 42.6%, p<0.005) and stage I/II (32/69, 46.4%, p<0.005) respectively. Moreover, abnormal expression was more frequent in tumors with positive lymph node metastasis (45/62, 72.6%), peritoneum seeding (10/11, 90.9%) and venous permeation (27/37, 73%) than that in tumors without lymph node metastasis (26/60, 43.3%, p<0.005), peritoneum seeding (61/111, 55.0%, p<0.05) and venous permeation (44/85, 51.8%, p<0.05). There is no statistical difference between E-cadherin expression and the status of perineural invasion or H. pylori infection. Analysis of survival for patients demonstrated that reduced E-cadherin expression was correlated with poor prognosis.

CONCLUSIONS

These data indicate that impaired expression of E-cadherin is an important characteristic of gastric cancer and contributes to histogenesis, tumor growth, metastasis and poor survival.

Gastric cancer risk in relation to Helicobacter pylori infection and subtypes of intestinal metaplasia

Helicobacter pylori (H. pylori) infection and intestinal metaplasia (IM) are each associated with an increased risk of gastric cancer (GC). To explore further the influences of H. pylori and IM on GC, H. pylori and subtypes of IM were evaluated in 135 sex and age-matched case and control pairs. Odds ratios (ORs) with 95% confidence intervals of developing GC were calculated for each risk factor using multiple logistic regression analysis. ORs for H. pylori infection and IM were 2.43 (1.29-4.65) and 4.59 (2.58-8.16), respectively, and those for different IM subtypes gave values of 0.82 (0.28-2.36) for type I, 2.03 (0.95-4.34) for type II and 39.75 (14.34-110.2) for type III. Stratification analysis by histological subtype and stage of GC showed a particularly high OR for IM in intestinal type (12.8, 4.73-34.83) and early GC (6.40, 2.25-18.18). Our data indicate that both H. pylori and IM are related to GC risk. Type III IM is a more specific marker of premalignancy, with relevance, in particular, to the early and intestinal type of GC.

Clinicopathological significance of altered loci of replication error and microsatellite instability-associated mutations in gastric cancer

Replication errors (RERs) judged by microsatellite instability and its associated mutations have been recognized as an important mechanism in tumorigenesis of gastric cancers (GCs). To gain a deeper insight into its significance, we examined the frequency of RERs using nine microsatellite markers and screened mutations in the polydeoxyadenine tract of the transforming growth factor beta type II receptor gene (TGF-betaRII) and polydeoxyguanine tracts of insulin-like growth factor II receptor and BAX genes. Twenty-four (30%) of 80 patients with GC had RERs, of which 3, 8, and 13 had one, two, and three or more loci, respectively. In 13 tumors with RERs in three or more loci, frameshift mutations of TGF-betaRII, insulin-like growth factor II receptor, and BAX were identified in 12, 3, and 2, respectively. Compared with GC with none, one or two RER-positive loci as a group, GC with RERs in three or more loci showed a significantly higher frequency of antral location (12 of 13 versus 35 of 67; P = 0.01), intestinal subtype (11 of 13 versus 30 of 67; P = 0.01), and previous Helicobacter pylori infection (12 of 13 versus 41 of 67; P = 0.05) and a lower incidence of lymph node metastasis (5 of 13 versus 49 of 67; P = 0.02) and tended to be in an advanced stage (12 of 13 versus 54 of 67; P = 0.28). These data indicate that GC with multiple RERs manifest distinct clinicopathological characteristics, and that a high frequency of frameshift mutations involving the TGF-betaRII gene may be causatively linked with tumorigenesis and progression.

Loss of pS2 protein expression is an early event of intestinal-type gastric cancer

To investigate the prevalence of pS2 expression in gastric cancer with respect to tumor histopathology, intestinal metaplasia and Helicobacter pylori (H. pylori) infection, pathologic specimens of 91 patients with gastric cancer were immunostained for pS2. Such immunoreactivity was correlated with the status of H. pylori infection, tumor staging, histology, subtyping, and associated intestinal metaplasia. Positive pS2 staining was seen throughout all non-neoplastic epithelia, and in all 9 patients with the complete type of intestinal metaplasia. In contrast, 21 of 45 incomplete type of intestinal metaplasia had negative pS2 staining (P < 0.001), and 54 out of 91 tumors (59.3%) showed loss of pS2 expression in the cancer tissues proper. There was no correlation of pS2 expression with age, gender, depth of invasion, duodenal involvement, lymph node metastasis, venous invasion or H. pylori infection. Negative pS2 staining was significantly higher in the intestinal (74.5%) and Borrmann type I, II, III (64.2%) tumors than the diffuse (43.2%, P < 0.005) and Borrmann type IV (20%, P < 0.05) tumors. Our results indicate that loss of pS2 expression may occur as an early event in the malignant transformation process of intestinal-type tumors.