Flavonoids modulate monocarboxylate transporter-1-mediated transport of gamma-hydroxybutyrate in vitro and in vivo.

The objective of this study was to determine the effects of flavonoids on the in vitro monocarboxylate transporter 1 (MCT1)-mediated transport and in vivo disposition of the drug of abuse, gamma-hydroxybutyrate (GHB). The uptake of GHB in rat MCT1 gene-transfected MDA-MB231 cells was significantly decreased in the presence of the flavonoids apigenin, biochanin A, chrysin, diosemin, fisetin, genistein, hesperitin, kaempferol, luteolin, morin, narigenin, phloretin, and quercetin, but was not affected by the flavonoid glycosides phloridzin and rutin. The IC(50) values for luteolin, morin, and phloretin were 0.41 +/- 0.14, 6.41 +/- 2.01, and 2.57 +/- 0.48 microM, with the inhibition mechanism for luteolin being competitive. [(3)H]Kaempferol and [(3)H]biochanin A did not exhibit MCT1-mediated uptake, suggesting that these flavonoids are not substrates for MCT1. The combination of luteolin and phloretin inhibited the uptake of GHB in a synergistic manner; however, the combination of luteolin and morin was antagonistic. GHB 1000 mg/kg was administered to rats by i.v. bolus, with or without the concomitant administration of luteolin 10 mg/kg i.v. After luteolin treatment, the renal and total clearances of GHB were significantly increased, probably because of inhibition of the MCT1-mediated renal reabsorption of GHB, and the sleep time significantly decreased (121 +/- 5 min versus 165 +/- 10 min) compared with control rats. Overall, the results of this study indicate that flavonoids from food or herbal products may significantly alter the pharmacokinetics and pharmacodynamics of MCT substrates.     

Autologous graft-versus-host disease: a novel approach for antitumor immunotherapy.

Autologous bone marrow transplantation (BMT) is a therapeutic option for the treatment of lymphohematopoietic malignancies and solid tumors. Despite the intensive cytoreductive therapy, however, the rates of tumor recurrence after autologous BMT remain unacceptably high. Current studies suggest that the administration of cyclosporine (CsA) disrupts the reconstitution of self-tolerance following autologous BMT leading to the induction of an autoimmune graft-versus-host disease (GVHD). Studies in a rat tumor model and preliminary clinical trials suggest that this autoimmune or autologous GVHD provides a significant antitumor effect. Moreover, the antitumor effect of autologous GVHD can be enhanced by administration of gamma-interferon, which upregulates the antigen recognized by the autoreactive effector cells of autologous GVHD. These studies indicate that the induction of an autoimmune GVHD after autologous BMT may be a promising immunotherapeutic approach for treatment of certain neoplastic diseases.     

Disseminating tumor cells and their interactions with leukocytes visualized in the brain.

Brain tumors are increasingly prevalent. Recent advances focus attention on individual, disseminated tumor cells that cannot be imaged or eliminated. Cells of the immune system may be ideally suited to attack individual tumor cells, but more basic understanding is needed. We describe a rat model, using the lacZ reporter gene, that allows identification of individual tumor cells, and tumor-leukocyte interactions in vivo. The model demonstrates how widely tumor can disseminate, without secondary tumorigenesis or recruitment of nonneoplastic cells. It demonstrates that leukocytes have access to disseminating tumor. Among its many applications, this work lays a foundation for developing cell-mediated immunotherapy against individual brain tumor cells.     

In vivo circumvention of human colon carcinoma resistance to bleomycin.

Metabolic inactivation of bleomycin (BLM) by cysteine proteinase-like enzymes is thought to be a major mechanism of BLM tumor resistance. We now report that the human colon carcinoma COLO-205 is highly resistant to BLM and that E-64, a cysteine proteinase inhibitor, sensitizes COLO-205 to BLM. Treatment of COLO-205-bearing nude mice with either E-64 (40 mg/kg) or BLM (10 mg/kg) alone did not inhibit COLO-205 growth. However, pretreatment with E-64 prior to BLM prevented these xenografts from growing. Analysis by high performance liquid chromatography of in vivo BLM metabolism following [3H]BLM A2 treatment of COLO-205-bearing nude mice showed a different metabolic profile among the various organs and the tumor. Whereas [3H]BLM A2 was the only major radioactive peak detected in sera and tumors, several metabolites, including deamido-BLM A2, were found in kidney, liver, and lung as early as 15 min. Pretreatment of mice with E-64 inhibited tumor, kidney, and lung BLM A2 metabolism. Furthermore, pretreatment with E-64 increased BLM A2 accumulation in tumors (6.1-fold), kidney (4.0-fold), lung (2.8-fold), liver (1.8-fold), and serum (1.7-fold). E-64 pretreatment did not enhance the major toxicity of BLM, pulmonary fibrosis, as determined by both lung hydroxyproline levels and histopathology. Thus, the cysteine proteinase inhibitor E-64 affects the metabolic fate and the levels of accumulation of BLM in vivo. These results demonstrate that resistance of human COLO-205 tumors to BLM can be circumvented by E-64 without enhancement of the major side effect of BLM, suggesting a possible clinical use of this combination therapy.     

An investigation of the suitability of bra fit in women referred for reduction mammaplasty.

Reduction mammaplasty is rationed in NHS plastic surgery provision, despite abundant evidence that most women who undergo this operation obtain significant improvement in their physical health and quality of life. We suspected that women seeking reduction mammaplasty often wear ill-fitting bras, which may exacerbate some of their symptoms. Therefore, we studied 103 women who attended a nurse-run pre-assessment clinic, asking them what size bra they currently wore and then measuring them to see whether their bra size was correct. We also questioned bra manufacturers, designers and shop bra fitters about bra manufacture, sizing and fitting techniques, and we reviewed these findings. Of the 102 women suitable for inclusion in the study, all wore the wrong size bra. Their mean 'claimed' back measurement was 36 inches (range: 30-42 in.) and their mean cup size was F (range: C-J). We found that all but one underestimated their back measurement (by a mean of 4 in.; range: -2-10 in.) and overestimated their cup size (by a mean of three sizes; range: one size smaller to seven sizes larger) when compared with manufacturers' fitting guidelines. Multiple regression analysis used to assess the relationships of various factors to incorrect bra sizing showed a strong link (Pearson correlation=0.54; P<0.001) between obesity and inaccurate back measurement. The reasons why women with breast hypertrophy wear incorrectly fitting bras are discussed. We conclude that obesity, breast hypertrophy, fashion and bra-fitting practices combine to make those women who most need supportive bras the least likely to get accurately fitted bras, so exacerbating the symptoms for which they seek surgery.     

Association of angiotensin II type 1 receptor gene polymorphism with essential hypertension

The renin-angiotensin system is involved in control of blood pressure and salt and fluid homeostasis. Genes for components of this system have been of major focus in research on the causation of the common, complex, polygenic trait, essential hypertension (HT). Association of an A→C variant at nucleotide 1166 of the angiotensin II type 1 receptor (AT₁R) gene with HT, but an absence of linkage of this locus with this disease, has been reported recently. Since confirmation in a different setting is imperative, we performed a cross-sectional case-control study of the A1166C variant in a well-characterized group of 108 Caucasian HT subjects with a strong family history (two affected parents) and early onset disease. Genotyping was by mismatch polymerase chain reaction/ Bfr I restriction fragment length polymorphism analysis. Frequency of the C¹¹⁶⁶allele was 0.40 in HTs and 0.29 in normotensives. The difference in genotype (χ²= 13, P = 0.0015) and allele (χ²= 5.3, P = 0.02) frequencies between the two groups was significant (odds ratio for CC vs AA+AC = 7.3 [95% CI, 1.9–31.9). The present results implicate the AT₁R gene, or a locus in linkage disequilibrium with the variant tested, in the causation of essential HT.     

Cerebral Emboli during Cardiac Surgery in Children

Background: Microemboli occur commonly during cardiac surgery in adults, and, when present, increase the risk of neuropsychological deficits. Their incidence and significance during correction of congenital heart disease is unknown. The authors hypothesized that microemboli would occur before bypass with right-to-left cardiac shunts and would also occur in large numbers when the aortic crossclamp was released in children during repair of congenital heart defects.

Methods: In 25 children studied with carotid artery Doppler, embolic signals were counted and timed in relation to 13 intraoperative events. Patients were classified as either at high risk (obligate right-to-left shunt or uncorrected transposition of the great arteries) or at low risk (net left-to-right shunt or simple obstructive lesions) for paradoxical (venous to arterial) emboli.

Results: The median number of emboli detected was 122 (range, 2-2,664). Forty-two percent of all emboli were detected within 3 min of release of the aortic crossclamp. The high-risk group had significantly more emboli (median, 66; range, 0-116) during the time interval before cardiopulmonary bypass than did the low-risk group (median, 8; range, 0-73), with P < 0.01. There was no significant difference between the high-and low-risk groups in the total number of emboli detected. There was no apparent association between number of emboli and gross neurologic deficits.     

Reduced stimulation of helper T cells by Ki-ras transformed cells.

A number of viral genes and cellular oncogenes inhibit major histocompatibility complex (MHC) antigen expression at the cell surface. In the case of inhibition of class I MHC antigens by viral genes this results in a reduced recognition by antigen-specific cytotoxic T cells. The activated Ki-ras cellular oncogene carried by the Ki-murine sarcoma virus (Ki-MuSV) in contrast inhibits class II MHC (or Ia) antigen expression on transformed cells. We have studied how transformation with Ki-ras affects recognition by alloreactive helper T cells. We found that the Ki-ras inhibition of class II MHC antigen expression led to greatly reduced stimulation of alloreactive T cells to proliferate and to secrete interferon-gamma (IFN-gamma). These findings support our hypothesis that the ability of an oncogene to reduce class II MHC antigen expression is crucial to its ability to produce tumour cells.