Enhanced immunogenicity of the cultured rat fibrosarcoma KMT-17 by cultivation in a low concentration of fetal calf serum

We examined in different culture conditions alterations in the tumorigenicity and immunogenicity of an A3 clone that had been derived from a rat fibrosarcoma KMT-17. When a fetal calf serum concentration in a culture medium was lowered from 10 to 1%, the tumorigenicity was diminished while the immunogenicity was enhanced in a reversible manner; this was accompanied by a reversible prolongation of the in vitro doubling time. These phenomena were not due to an increase in the quantities of the original tumor-associated antigen and/or of the rat major histocompatibility complex (RT1) but seemed to be due to the appearance of a unique antigen(s) that was detected by an antibody taken from rats immunized with A3 tumor cells cultured in the low fetal calf serum concentration; this antigen(s) may consist of glycoprotein and exist as a crypt antigen(s). These phenomena were measured by an absorption test and flow cytometric analysis. Our observations suggest that the in vitro culture condition of tumor cells, in particular their culturing in the low fetal calf serum concentration medium, modifies the surface of tumor cells and causes a diminishment in their tumorigenicity and an enhancement of their immunogenicity.     

Modification of beta 2-microglobulin with D-glucose or 3-deoxyglucosone inhibits A beta 2M amyloid fibril extension in vitro.

beta 2-microglobulin (beta 2M) is a major constituent of amyloid fibrils (fA beta 2M) deposited in patients with A beta 2M amyloidosis. Recently, advanced glycation end products (AGE) of beta 2M and fA beta 2M have been suggested to play an important role in the pathogenesis of A beta 2M amyloidosis. We first characterized the states of AGE modification of fA beta 2M. Western blot analysis with a monoclonal anti-AGE antibody showed that purified fA beta 2M was naturally modified with AGE. Immunohistochemical studies of amyloid-deposited tissue have revealed a patchy distribution of the AGE-modified area in the amyloid deposits. Then we modified beta 2-m either with D-glucose or with 3-deoxyglucosone (3-DG) and investigated the effect of these modification on fA beta 2M extension in vitro, using the recently established first-order kinetic model of fA beta 2M extension in vitro. Western blot analysis and enzyme linked immunosorbent assay with a monoclonal anti-AGE antibody showed that these sugar-modified beta 2M contained AGE. During the incubation of fA beta 2M with native beta 2-m at 37 degrees C, the fluorescence of thioflavin T increased without a lag phase and proceeded to equilibrium. On the contrary, only a slight increase in fluorescence was observed during the incubation of fA beta 2M with sugar-modified beta 2M. Moreover, sugar-modified beta 2M exhibited a dose-dependent inhibitory effect on the extension reaction of fA beta 2M with native beta 2M. These results may suggest that in some in vivo situations, the modification of beta 2-m with AGE could play an inhibitory role for the formation of fA beta 2M.     

Gangliosides as markers for murine lymphocyte subpopulations

Antibodies to GM1 ganglioside were used to study murine lymphocyte populations. In A, AKR, and BALB/c mice, anti-GM1 reacts with thymocytes and peripheral T cells. This reactivity of anti-GM1, studied by immunofluorescence, is independent of Thy-1 type and appears to be related to the reactivity of cross-reacting antibodies to asialo GM1 and GD1b, rather than GM1 itself. In addition, a subpopulation of lymphocytes reacting with anti-GM1 and anti-immunoglobulin has been found in approximately 26% of the peripheral lymphocytes of C3H mice, nude mice, and nude heterozygotes. This subpopulation is found in small numbers in A, AKR, and BALB/c mice. These studies demonstrate that antibodies to a chemically defined antigen can be used to identify T cells in many strains of mice and may delineate previously unrecognized lymphocyte subpopulations.     

Insulin resistance raises the risk for recurrence of stage I hepatocellular carcinoma after curative radiofrequency ablation in hepatitis C virus‐positive patients: A prospective,case series study

Aim: Several studies have reported that insulin resistance raises the risk of primary hepatocellular carcinoma (HCC). We conducted a prospective, case series study to test the impact of insulin resistance on the recurrence after curative radiofrequency ablation (RFA) of stage I HCC in HCV‐positive patients. Methods: From January 2006 to December 2007, 226 consecutive patients underwent treatment for primary HCC at our institutions, including 37 stage I cases. Among them, 33 were HCV‐positive, and three, six and 24 received curative surgery, transarterial chemoembolization or RFA, respectively. In the 24 patients treated with RFA, recurrence‐free survival was analyzed using the Kaplan–Meier method. The factors contributing to recurrence of HCC were subjected to univariate and multivariate analyses using the Cox proportional hazards model. Insulin resistance was estimated by the Homeostatic Model Assessment of Insulin Resistance (HOMA‐IR). Results: Kaplan–Meier analysis showed that the recurrence‐free survival was lower in patients with higher HOMA‐IR (>2.3, P = 0.0252) or with lower serum albumin level (<3.3 g/dL, P = 0.0004). In the univariate analysis, HOMA‐IR (P = 0.0420) and albumin (P = 0.0036) were significantly associated with recurrence of HCC. Multivariate analysis revealed albumin (odds ratio = 0.01, 95% confidence interval = 0.0002–0.015, P = 0.0001) and HOMA‐IR (odds ratio = 3.85, 95% confidence interval = 1.57–14.2, P = 0.0015) to be independent predictors for recurrence of HCC. Conclusion: Serum albumin level and HOMA‐IR were independent risk factors for recurrence of stage I HCC after curative RFA in HCV‐positive patients. Patients with these factors require closer surveillance.     

Adaptation and remodeling of vascular wall; biomechanical response to hypertension

Living organs, tissues, and cells functionally adapt themselves to mechanical demands, and remodel by changing geometry, structure, and properties. The key factor for this phenomenon is “Mechanical Stress”. Major stresses applied to blood vessels inside the body are: (1) hoop stress induced by blood pressure, that is normal stress in the wall circumferential direction, (2) wall shear stress developed by blood flow, and (3) axial stress by elongation in the axial direction. This review article deals with biomechanical studies on the responses of arterial and venous wall to the elevation of blood pressure. One of the specific biomechanical manifestations to arterial wall adaptation in response to hypertension is wall hypertrophy. This restores circumferential wall stress, i.e. hoop stress, at in vivo operating pressure to a normal value, and changes arterial stiffness to an optimal level. Vascular smooth muscle cells are activated by hypertension. Essentially similar phenomena are also observed in venous wall.     

High frequency of human papillomavirus infection in carcinoma of the urinary bladder.

BACKGROUND AND METHODS. The prevalence of type 6, 11, 16, 18, and 33 human papillomavirus (HPV) was investigated with the polymerase chain reaction (PCR) on formalin-fixed, paraffin wax-embedded material, including 48 neoplastic and 21 normal urinary bladder specimens. The PCR-amplified DNA were analyzed by gel electrophoresis and dot blot and Southern blot hybridization. Some tissues were tested further by nonisotopic in situ hybridization. RESULTS. HPV DNA was detected in 39 (81%) of 48 carcinomas and 7 (33%) of 21 normal urinary bladder specimens. The presence of high-risk HPV (types 16, 18, and 33) was increased significantly in carcinoma cases (62%) as compared with normal specimens (14%) (P less than 0.01). Similarly, multiple HPV infections were significantly higher in carcinoma (60%) than in the normal tissues (5%) (P less than 0.01). The overall and high-risk HPV infections in both neoplastic and normal specimens were distributed almost equally in male and female patients. There was no significant correlation between positive results for HPV and histologic grades of the carcinoma. CONCLUSIONS. These results demonstrate that the urinary bladder in both sexes is another site where infection with the common genital tract HPV may carry a risk of malignant transformation.