Preoperative concurrent chemotherapy and radiation therapy followed by surgery for esophageal cancer.

Currently, the most promising strategy to improve the prognosis of advanced esophageal cancer is preoperative chemoradiation (CRT) followed by surgery. The superiority of CRT over radiation therapy alone has been demonstrated by several randomized studies. Many phase II studies of CRT followed by surgery have shown that the pathologic complete response (CR) rate ranges from 17 to 40%, and the median survival time (MST) is 12 to 31.3 months. Five randomized trials have compared preoperative CRT followed by surgery with surgery alone for resectable esophageal cancer, and four of them did not find any significant survival benefit for the combined treatment group. There are several issues in interpreting these findings, such as the quality of the surgery, the accuracy of the preoperative staging, the statistical power and design of the trials. Until comprehensive evaluation can be done, the standard therapy for resectable esophageal cancer should be considered to be surgery alone. The histological response in the resected specimen correlates well with the prognosis. Patients with pathologic CR display significantly better survival than those with microscopic residual cancer cells in the resected specimens. These findings suggest that more potent regimens leading to higher pathologic CR rates should improve the prognosis. Chemotherapy or radiation therapy sensitivity testing needs to be established. If accurate prediction of the response is possible prior to therapy, non-responders can be excluded. Cell cycle-related genes, apoptosis-related genes, and drug metabolizing genes have been investigated in many pilot studies and need to be evaluated by large-scale clinical studies. At present, pathologic CR can not be accurately diagnosed before surgery. Endoscopic biopsy is also unreliable for the diagnosis. In the future, new diagnostic tools such as positron emission tomography scanning, a sensitivity test or molecular markers may enable accurate diagnosis of pathologic CR to guide the choice of treatment strategies for individual patients.     

Antigen presentation by a B-cell line transfected with cloned immunoglobulin heavy- and light-chain genes specific for a defined hapten.

The rearranged genes encoding immunoglobulin heavy (mu) and light (kappa) chains specific for the hapten 2,4,6-trinitrophenyl (Tnp) were introduced into a B-lymphoma line that bears surface IgG with an unknown specificity and expresses surface Ia molecules. A transformant expressing surface IgM specific for Tnp was obtained. The transformant was found to present Tnp-proteins to antigen (protein)-specific T cells far more efficiently than the parenteral B-lymphoma line. This artificial system, utilizing recombinant DNA technology and gene transfer, provides several approaches for the study of T-cell-B-cell interactions.     

Relationship between in vivo first-order intestinal absorption rate constant and the membrane permeability clearance

An attempt was made to explore the quantitative relationship between the intestinal absorption data obtained from in vivo studies and in situ perfusion studies. The time course of the fraction remaining to be absorbed of L-glucose, erythritol, and urea in the small intestine following the intrajejunal administration to rats was described by a one-compartment model. Thus derived first-order intestinal absorption rate constants (ka) obtained from the in vivo studies in rats were compared with the membrane permeability clearances (CLa,m) estimated in a single-pass perfusion system. Not only were ka and CLa,m in the same increasing order of L-glucose less than erythritol less than urea, but also the operational luminal volumes given as CLa,m/ka were in agreement with the in vivo luminal volume of jejunum estimated by an inulin dilution method. This result suggests that the in vivo intestinal absorption rate (or ka) can be correlated with the intestinal membrane permeability (or CLa,m) by taking the in vivo luminal volume into account.     

Recurrent mediastinal liposarcoma twenty years after the initial operation: case report

We report a case of mediastinal liposarcoma, recurrent after 20 years. A 58-year-old man who presented with dyspnea on exertion was found to have a large mediastinal tumor in chest computed tomography (CT), and he was referred to our hospital. He had undergone an extirpation of a mediastinal liposarcoma about 20 years earlier, and we suspected its recurrence. Because the tumor was very large, it was removed in two stages. Histologically it was diagnosed as a recurrence of the previous well-differentiated liposarcoma. Although liposarcoma is one of the most common soft-tissue sarcomas in adults, a mediastinal liposarcoma is rare. Because the recurrence rate is very high, it is necessary to follow up carefully over a long term.     

A minute small-cell lung cancer showing a latent phase early in growth.

A minute small-cell lung cancer measuring 8 x 5 mm was detected and serially imaged by computed tomography for about a year preceding resection. Although this solid nodule showed a short overall doubling time (76 days), the growth curve included an early phase without apparent growth prior to the phase of rapid growth. Accordingly, lung cancer cannot be ruled out when a small nodule (<10 mm) does not enlarge in the first several months of computed tomographic follow-up.