Treatment of mucosa-associated lymphoid tissue lymphoma of the stomach with radiation alone

PURPOSE: Mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach (MLS) has recently been defined as a distinct clinicopathologic entity, often associated with Helicobacter pylori infection. Many regard antibiotic therapy as the primary treatment of MLS, but in the absence of H pylori infection, or when salvage of antibiotic failures is required, gastrectomy and/or chemotherapy have frequently been used. This study evaluates the efficacy of low-dose radiotherapy alone as an alternative to surgery. PATIENTS AND METHODS: Seventeen patients with stage I to II(2) low-grade MLS without evidence of H pylori infection or with persistent lymphoma after antibiotic therapy of associated H pylori infection were included in this series. Median age was 69 years (range, 39 to 84). Median total radiation dose was 30 Gy (range, 28.5 to 43.5 Gy) delivered in 1.5-Gy fractions within 4 weeks to the stomach and adjacent lymph nodes. Following treatment, all patients underwent endoscopic evaluation and biopsy at a median of 4 months, at 6-month intervals to 2 years, and annually thereafter. RESULTS: All obtained a biopsy-confirmed complete response. At a median follow-up time of 27 months (range, 11 to 68) from completion of radiotherapy, event-free survival was 100%. Treatment was well tolerated, with no significant acute side effects. All remained asymptomatic at last follow-up. CONCLUSION: These results suggest that effective treatment of MLS with low-dose radiation therapy alone is feasible and safe, and allows stomach preservation. Longer follow-up evaluation is required to determine the long-term efficacy of this treatment approach and its side effects. Further studies should clarify the indications for radiotherapy in H pylori-negative or antibiotic-resistant cases of MLS.     

Antibodies to an NH2-terminal fragment of betaS globin. I. Preparation and radioimmunoassay

Polypeptide fragments corresponding to the NH2-terminal 55 amino acids of betaS and betaA globins were prepared by cyanogen bromide treatment of globin and isolated by gel filtration on Sephadex G-50. Sheep were immunized with the isolated NH2-terminal fragments, and one of these sheep produced precipitating antibodies to the NH2-terminal fragment of betaS globin. These antibodies also reacted with betaA and betaS globin and hemoglobins A and S, as shown by immunodiffusion and quantitative precipitation studies. A radioimmunoassay was developed using the radioiodinated NH2-terminal fragment as tracer, and dextran-coated charcoal for separating bound and free peptide. The radioimmunoassay was used to characterize the interaction of the antibodies and the NH2-terminal fragment of betaS globin.     

A New Grid Block System for Reducing Grid Orientation Effect

Abstract

The grid orientation effect (GOE) is a long-standing problem plagueing reservoir simulators that employ finite difference schemes. A rotation of the computational grids yields a substantially different solution under certain circumstances. A Cartesian grid with one axis parallel to the line joining an injector and producer gives a solution significantly different from a grid that has the axes oriented at 45° to this line. This article presents a new grid system that can reduce the grid orientation effect. This system involves using a unique grid-block assignment where rectangular grid blocks are interspersed with octagonal grid blocks. The boundaries are populated with triangular grid blocks. The entire domain consists of a “structured” grid block system referred to as the hybrid grid block (HGB).     

The apple and your eye: Visual and taste rank-ordered probit analysis with correlated errors

I look at data from an experiment in which people rank apples according to how they think they will taste. They are then blindfolded and rank how they actually taste. I estimate a multinomial rank-ordered probit model with correlated errors between the taste and visual rankings. I find that the errors for visual characteristics are correlated based on coloring, while the errors for taste are correlated based on sweetness and tartness. Allowing for correlation between the errors in the two regressions shows that, although people often misperceive apple taste based upon visual cues, they do so in systematic ways. People who prefer the looks of an apple they think to be tart (Granny Smith), will like the taste of other apples which are also tart but less well-known (Jonagold).