Methylene blue staining of dysplastic and nondysplastic Barrett's esophagus: an in vivo and ex vivo study.

BACKGROUND AND STUDY AIMS: Methylene blue selectively stains specialized columnar epithelium in Barrett's esophagus with high accuracy. We prospectively evaluated the methylene blue staining properties of dysplastic and nondysplastic Barrett's esophagus and the association of these properties with the risk for dysplasia and cancer. PATIENTS AND METHODS: In a ex vivo study, we mapped, photographed, and sampled esophagectomy specimens with high grade dysplasia and/or early adenocarcinoma before and after methylene blue staining. In a concurrent in vivo study, we performed methylene blue staining and characterized methylene blue stain characteristics. Pathologists estimated the proportion of specialized columnar epithelium in each specimen and graded dysplasia. RESULTS: We examined 551 biopsies from 47 patients with biopsy-proven Barrett's esophagus and 48 sections from five surgical specimens with Barrett's esophagus and dysplasia and early adenocarcinoma. The accuracy of ex vivo and in vivo methylene blue staining for specialized columnar epithelium was 87% and 90%, respectively. It was influenced by the length of Barrett's esophagus, biopsy location, and the presence of esophagitis and/or dysplasia. Light to absent staining (p = 0.01) and moderate to marked heterogeneity (p = 0.01) were significantly associated with high grade dysplasia or cancer in the univariate analysis and in a multivariate model that adjusted for the length of Barrett's esophagus and the presence of a lesion. These staining characteristics were present in all patients with severe dysplasia and/or adenocarcinoma. CONCLUSIONS: Highly dysplastic or malignant Barrett's esophagus stains differently with methylene blue. Increased heterogeneity and decreased methylene blue stain intensity are significant independent predictors of high grade dysplasia and/or cancer. These features may help to direct biopsies in patients without a lesion.

Loss of fragile histidine triad expression in colorectal carcinomas and premalignant lesions.

Abnormal expression of the fragile histidine triad (FHIT) candidate tumor suppressor gene has been observed in a variety of human tumors, but little is known about its expression during colorectal tumorigenesis. Sections of 70 aberrant crypt foci (ACF), 55 adenomas, 84 primary colorectal carcinomas, and 13 metastatic lesions were evaluated immunohistochemically for Fhit expression. All normal colonic epithelium showed a strong expression of Fhit; 44% of carcinomas showed a marked loss or absence of Fhit expression. The proportion of carcinomas with reduced expression showed an increasing trend (a) with decreasing differentiation and (b) in tumors with metastases (62%) compared with tumors without metastases (38%). The proportion of metastatic lesions (12 of 13) with reduced expression of Fhit was even greater. Although only a small proportion of ACF and adenomas showed a reduction of Fhit expression, the reduced expression of Fhit was strongly associated with the degree of dysplasia in both ACF (P = 0.0002) and adenomas (P = 0.0085). The findings of reduced expression of Fhit in a small proportion of colonic precancerous lesions and in increased proportions of primary and metastatic colorectal cancers suggest that Fhit plays a role in the development and progression of some colon carcinomas.

Resetting of DDD pulse generators due to cold exposure.

We encountered resetting of three DDD pulse generators to the VVI mode, one at the time of implantation and two others just before implantation, and we believe this resulted from cold exposure during shipment. Consequently we analyzed the effect of cold exposure on five lithium-powered DDD pulse generators from different manufacturers. Cold exposure caused resetting of three of the five DDD pulse generators to the VVI mode. Only one of the reset pulse generators responded to application of the magnet by conversion to the asynchronous (VOO) mode, while the other two remained in the VVI mode. All DDD pulse generators should be routinely interrogated before implantation. If found to be reset, the likelihood of cold exposure is very high and the pulse generator can generally be reprogrammed to the DDD mode. The absence of a magnet response in reset DDD pulse generators appropriately inhibited and functioning in the VVI mode should not be interpreted as component failure when no output is observed.

Evaluation of the PaT Stat Kinetic UV Test set for the determination of phenylalanine and tyrosine in serum or plasma.

We have evaluated the PaT Stat Kinetic UV Test Kit for the simultaneous determination of phenylalanine (Phe) and tyrosine (Tyr) in plasma or serum. The Phe and Tyr concentrations measured with the kit show a coefficient of variation of about 15% for both within- and between-day determinations. The assays for both Phe and Tyr are linear to concentrations of at least 18 mg/dL without predilution of the specimen. Concentration differences of as little as 0.5 mg/dL are distinguishable. No significant interference was found from either phenylpyruvate or phenyllactate at levels up to 0.5 mM, nor from bilirubin, haemoglobin, or triglycerides at levels well above those generally found in clinical specimens. A comparative study of 70 clinical specimens, using the kit method and an amino acid analyzer (AAA) showed a linear relationship. Least-squares analysis of the data yielded the following parameters (AAA as reference): slope = 0.93 to 1.00, intercept = 0.04 to 0.21, correlation coefficient = 0.97 to 0.98. We conclude that the kit is suitable for the determination of Phe and Tyr in plasma or serum and can enable any laboratory equipped with a recording UV-spectrophotometer to assay these two amino acids for the dietary management of PKU.

Evaluation of a method for enzymic radiochemical assay of tobramycin and amikacin in serum.

This enzymic radiochemical procedure for measuring tobramycin and amikacin in serum is based on the transfer of the 14C-acetyl group from [14C]acetyl-coenzyme A to the 6' nitrogen atom of the drug by the enzyme kanamycin 6'-acetyltransferase (EC 2.3.1.55). The transfer, stoichiometric and quantitative, is complete after 10-min incubation at 37 degrees C. The labeled acetylaminoglycoside is adsorbed onto phosphocellulose paper discs, which are washed to removed any unreacted [14C]acetyl-coenzyme A. The radioactivity is then eluted into liquid scintillation counting vials and counted for 1 min each. The assay detects as little as 2 ng of either drug and the standard curve is linear into the toxic range of concentrations. Most of the commonly administered aminoglycosides act as substrates in the assay, except for the C1 component of gentamicin C complex. Neither hemolysis, lipemia, nor icterus interfere with the assay. Results compare favorably with those determined by radioimmunoassay and a microbiological method.