Microsatellite instability in young patients with sporadic colorectal adenomas.

BACKGROUND/AIMS: This study was designed to determine the prevalence of microsatellite instability (MSI) among colorectal adenomas detected in patients ≤ 40 years of age and to compare the prevalence of MSI in young (≤ 40 years) and older (>40 years) patients with colorectal adenomas. Additionally, we attempted to identify the underlying cause of MSI in these patients. METHODOLOGY: We prospectively tested for the presence of MSI using five NCI markers in samples from the two patient groups. The frequency of MSI was compared and the underlying causes of MSI were determined by methylation specific PCR and germ-line mutation analysis for mismatch repair genes. RESULTS: The frequency of MSI was higher in the ≤ 40 group than the >40 group (31.4% and 6.4%, respectively, p=0.0004). The MSI-high pattern was also more prevalent in the ≤ 40 group than the >40 group (15.7% and 2.5%, respectively, p=0.014). The hypermethylated hMLH1 gene was demonstrated in 7/8 (87.5%) patients with MSI-high in the ≤ 40 group and in 1/2 (50.0%) patients with MSI-high in the >40 group. No study subject showed a germline mutation of hMLH1 or hMSH2. CONCLUSIONS: MSI-high was more frequent in young (≤ 40 years) patients with colorectal adenoma than in older (>40 years) patients. Hypermethylation of the hMLH1 gene appears to be an important cause of MSI-high in these patients.

StAR and steroidogenic enzyme transcriptional regulation in the rat brain: effects of acute alcohol administration.

In this study, we showed the presence of steroidogenic acute regulatory protein (StAR) mRNA in the rat brain using Northern blot analysis and revealed its localization using in situ hybridization histochemistry. Although the expression level is less than peripheral steroidogenic organs, the brain has two kinds of StAR transcripts with the same size as peripheral endocrine organs. As expected, StAR mRNA levels were maintained in the brain after gonadectomy and adrenalectomy, which indicates its independent expression. Acute alcohol administration affected the mRNA expression of a variety of steroidogenic enzymes, as well as StAR, in several brain regions, and these changes varied from one region to another. It is suggested that StAR may take part in brain steroidogenesis along with steroidogenic enzymes and that various neurosteroids are synthesized differentially to meet local demands.

Incidence and polymerase chain reaction assay of Listeria monocytogenes from raw milk in Gyeongnam Province of Korea.

A total of 50 raw milk samples from Gyeongnam Province of Korea were examined for the incidence of Listeria monocytogenes between July 1998 and August 1998. L. monocytogenes isolated by biochemical test was confirmed by polymerase chain reaction (PCR) with two sets of primers designed from the invasion-associated protein (iap) gene. After standard PCR with external primers, the amplified DNA was confirmed by a second round of PCR with internal primers (nested PCR). Both the external and internal primers generated 468-bp and 287-bp products. respectively. Only one (G9 strain) of the three suspect samples that tested positive in biochemical tests for L. monocytogenes from 50 raw milk samples was also PCR positive. Following this procedure. PCR-positive G9 strain was confirmed by Southern blot using the 287-bp internal iap probe again. The detection limit of G9 strain by standard PCR assay was as few as 102 cells, equivalent to approximately I pg of L. monocytogenes DNA. These PCR assays may be useful for novel detection as well as rapid confirmation for L. monocytogenes from food samples and the field.

Detection of aflatoxin-producing molds in Korean fermented foods and grains by multiplex PCR.

An assay based on multiplex PCR was applied for the detection of potential aflatoxin-producing molds in Korean fermented foods and grains. Three genes, avfA, omtA, and ver-1, coding for key enzymes in aflatoxin biosynthesis, were used as aflatoxin-detecting target genes in multiplex PCR. DNA extracted from Aspergillus flavus, Aspergillus parasiticus, Aspergillus oryzae, Aspergillus niger, Aspergillus terreus, Penicillium expansum, and Fusarium verticillioides was used as PCR template to test specificity of the multiplex PCR assay. Positive results were achieved only with DNA that was extracted from the aflatoxigenic molds A. flavus and A. parasiticus in all three primer pairs. This result was supported by aflatoxin detection with direct competitive enzyme-linked immunosorbent assay (DC-ELISA). The PCR assay required just a few hours, enabling rapid and simultaneous detection of many samples at a low cost. A total of 22 Meju samples, 24 Doenjang samples, and 10 barley samples commercially obtained in Korea were analyzed. The DC-ELISA assay for aflatoxin detection gave negative results for all samples, whereas the PCR-based method gave positive results for 1 of 22 Meju samples and 2 of 10 barley samples. After incubation of the positive samples with malt extract agar, DC-ELISA also gave positive results for aflatoxin detection. All Doenjang samples were negative by multiplex PCR and DC-ELISA assay, suggesting that aflatoxin contamination and the presence of aflatoxin-producing molds in Doenjang are probably low.

Double-layered PTFE-covered nitinol stents: experience in 32 patients with malignant esophageal strictures.

We evaluated the effectiveness of a double-layered polytetrafluoroethylene (PTFE)-covered nitinol stent in the palliative treatment of malignant esophageal strictures. A double-layered PTFE-covered nitinol stent was designed to reduce the propensity to migration of conventional covered stent. The stent consists of an inner PTFE-covered stent and an outer uncovered nitinol stent tube. With fluoroscopic guidance, the stent was placed in 32 consecutive patients with malignant esophageal strictures. During the follow-up period, the technical and clinical success rates, complications, and cumulative patient survival and stent patency were evaluated. Stent placement was technically successful in all patients, and no procedural complications occurred. After stent placement, the symptoms of 30 patients (94%) showed improvement. During the mean follow-up of 103 days (range, 9-348 days), 11 (34%) of 32 patients developed recurrent symptoms due to tumor overgrowth in five patients (16%), tumor ingrowth owing to detachment of the covering material (PTFE) apart from the stent wire in 3 (9%), mucosal hyperplasia in 2 (6%), and stent migration in 1 (3%). Ten of these 11 patients were treated by means of placing a second covered stent. Thirty patients died, 29 as a result of disease progression and 1 from aspiration pneumonia. The median survival period was 92 days. The median period of primary stent patency was 190 days. The double-layered PTFE-covered nitinol stent seems to be effective for the palliative treatment of malignant esophageal strictures. We believe that the double-layer configuration of this stent can contribute to decreasing the stent's migration rate.

Malignant gastric outlet obstructions: treatment by means of coaxial placement of uncovered and covered expandable nitinol stents.

PURPOSE: To assess whether coaxial placement of uncovered and covered expandable nitinol stents overcomes the disadvantages of the increased migration rate seen with covered stents and the tumor ingrowth seen in uncovered stents in the treatment of malignant gastric outlet obstructions. MATERIALS AND METHODS: Two types of expandable nitinol stent were designed: an uncovered stent and a covered stent. Under fluoroscopic guidance, the uncovered and covered stents were placed coaxially with complete overlap in 39 consecutive patients with malignant gastric outlet obstruction caused by stomach cancer. Food intake capacity was graded on a scale of 0-4. Stent patency rate was estimated by the Kaplan-Meier method. RESULTS: Technical success rate was 97% (38 of 39 patients). After stent placement, food intake capacity improved at least one grade in 36 patients. Stent migration occurred in three patients (8%), that is, partial (n = 2) or complete (n = 1) upward migration of the inner covered stent into the stomach. Two of these patients were treated by placement of an additional covered stent. During the mean follow-up period of 134 days (range, 15-569 d), 10 patients developed recurrent symptoms of obstruction with tumor overgrowth being the most common cause. Nine underwent placement of an additional covered stent with good results. The median period of primary stent patency was 157 days (mean, 278 d). The 30-, 60-, and 180-day patency rates were 97%, 91%, and 39%, respectively. Four patients (10%) died within 1 month after the procedure. CONCLUSION: Coaxial stent placement technique seems to contribute to decreasing the migration rate of the stent and decrease the rate of recurrent obstruction by preventing or delaying tumor ingrowth.