Macroglial and retinal changes in hypercholesterolemic rabbits after normalization of cholesterol levels

This study evaluates hypercholesterolemic rabbits, examining the retinal changes in Müller cells and astrocytes as well as their variations after a period of normal blood-cholesterol values induced by a standard diet. New Zealand rabbits were divided into three groups: G0, fed a standard diet; G1A, fed a 0.5% cholesterol-enriched diet for 8 months; and G1B, fed as G1A followed by standard diet for 6 months. Eyes were processed for transmission electron microscopy and immunohistochemistry (GFAP). While G1B resembled G0 more than did G1A, they shared alterations with G1A: a) as in G1A, Müller cells were GFAP+, filled spaces left by axonal degeneration, formed glial scars and their nuclei were displaced to the nerve-fibre layer. The area occupied by the astrocytes associated with the nerve-fibre bundles (AANFB) and by perivascular astrocytes (PVA) in G1A and G1B was significantly lower than in controls. However, no significant differences in PVA were found between G1A and G1B. In G1B, type I PVA was absent and replaced by hypertrophic type II cells; b) Bruch's membrane (BM) was thinner in G1B than in G1A; c) the retinal pigment epithelium (RPE) cytoplasm contained fewer lipids in G1B than in G1A; d) in G1A and G1B choriocapillaris and retinal vessel showed alterations with respect to G0; e) cell death and axonal degeneration in the retina were similar in G1A and G1B. The substitution of a hyperlipemic diet by a standard one normalizes blood-lipid levels. However, the persistence of damage at retinal vessels and BM-RPE could trigger chronic ischemia.     

Serum C-peptide levels and breast cancer risk: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)

It has been hypothesized that chronic hyperinsulinemia, a major metabolic consequence of physical inactivity and excess weight, might increase breast cancer risk by direct effects on breast tissue or indirectly by increasing bioavailable levels of testosterone and estradiol. Within the European Prospective Investigation into Cancer and Nutrition (EPIC), we measured serum levels of C-peptide--a marker for pancreatic insulin secretion--in a total of 1,141 incident cases of breast cancer and 2,204 matched control subjects. Additional measurements were made of serum sex hormone binding globulin (SHBG) and sex steroids. Conditional logistic regression models were used to estimate breast cancer risk for different levels of C-peptide. C-peptide was inversely correlated with SHBG and hence directly correlated with free testosterone among both pre and postmenopausal women. C-peptide and free estradiol also correlated positively, but only among postmenopausal women. Elevated serum C-peptide levels were associated with a nonsignificant reduced risk of breast cancer diagnosed up to the age of 50 years [odds ratio (OR)=0.70, (95% confidence interval (CI), 0.39-1.24); ptrend=0.05]. By contrast, higher levels of C-peptide were associated with an increase of breast cancer risk among women above 60 years of age, however only among those women who had provided a blood sample under nonfasting conditions [OR=2.03, (95% CI, 1.20-3.43); ptrend=0.01]. Our results do not support the hypothesis that chronic hyperinsulinemia generally increases breast cancer risk, independently of age. Nevertheless, among older, postmenopausal women, hyperinsulinemia might contribute to increasing breast cancer risk.     

Advanced breast cancer: anti-progressive immunotherapy using a thermostable autologous hemoderivative

Introduction Advanced breast cancer patients, acquired-chemotherapy resistant and in progression, are therapeutically terminal. We tested a recently described medical procedure using a thermostable autohemoderivative purported to inhibit tumor growth possibly through an immunological mechanism of action.Patients and methods Metastatic breast cancer patients, chemotherapy-resistant, high CEA and CA 15-3 plasma levels of tumor markers, in progression, were 2-group randomized. Group 1 received the test procedure and Group 2 adequate measures to be comparable control. From 121 included patients, 108 could be evaluated. During 8-month follow-up period, tumor growth, number of cases attaining clinical non-progressive status and mortality were monthly assessed. Immunologic effect was assessed by delayed type hypersensitivity test and lymphocyte proliferation assay. Responding-tumors histopathologies were studied. The proteome of the autologous immunogen was characterized by 2-D electrophoresis.Results and discussion In a significant number of cases, the test procedure promoted inhibition of tumor growth, non-progressive disease status, and lower cumulative mortality. These clinical results were associated with polyvalent immunization against several tested antigens: the hemoderivative used for treatment, the blood tumor markers and the derivative obtained from a regulatory lymphocyte population (CD4+CD25+). Interference with this regulatory activity could explain the selective autoimmunity suggested by the histopathology findings in responding tumors. The thermostability could be an essential property of the immunogen hemoderivative.Conclusion The thermostable autohemoderivative tested is antigenically polyvalent and promoted a polytargeted immune response associated to a tumor anti-progressive effect, consequently, acting as an autohemoderivative cancer vaccine.     

EcoRI polymorphism of the metastasis-suppressor gene NME1 in Mexican patients with breast cancer

Summary Human breast cancer cells with high metastatic potential show reduced expression of the metastasis-suppressor gene NME1. There are two polymorphic sites for the restriction enzymes BglII and EcoRI, both detectable by Southern blot analysis. Although the BglII site has been analyzed for loss of heterozygosity, the biallelic EcoRI site polymorphism has not been studied in association with breast cancer, complications or metastasis. We analyzed EcoRI site allele frequencies in Mexican patients with breast cancer, using polymerase chain reaction -restriction fragment length polymorphisms. The polymorphic allelic frequencies in the cases and reference groups were 0.4215 and 0.3375, respectively; this difference was not statistically significant (χ²=0.8687, p=0.3512). Thus, EcoR1 polymorphic site was not associated with breast cancer in this series, but could be analyzed in association with metastases and might be informative in the evaluation of loss of heterozygosity in women with breast cancer.     

Candesartan cilexetil in children with hypertension or proteinuria: preliminary data

The angiotensin II receptor blockers irbesartan and losartan effectively reduce blood pressure and proteinuria in childhood. We were impressed by the neutral taste and the small size of the candesartan cilexetil tablets. This angiotensin II receptor blocker was used during 4 months in 17 pediatric patients (aged 0.5–16, median 4.5 years) with chronic arterial hypertension (n=6), overt proteinuria (n=2), or both (n=9). The initial candesartan dose of 0.23 (0.16–0.28) mg/kg body weight once daily (median and interquartile ranged) was doubled in ten patients [final dose 0.35 (0.22–0.47) mg/kg body weight]. No adverse clinical experiences were noted on candesartan. Candesartan increased plasma potassium by 0.3 (0.0–0.8) mmol/l (P<0.01). In children with arterial hypertension, blood pressure decreased by 9 (3–13)/9 (3–18) mmHg (P<0.01); in those with overt proteinuria the urinary albumin/creatinine ratio decreased by 279 (33–652) mg/mmol (P<0.05). In conclusion, in children candesartan reduces blood pressure and proteinuria with an excellent short-term tolerability profile.     

Panel of reactive T cells as a measurement of primed cellular alloimmunity in kidney transplant candidates

Pretransplantation panel reactive antibody (PRA) testing assesses posttransplantation risk for antibody-mediated graft injury. It was postulated analogously that screening for effector/memory alloreactive T cells by "panel of reactive T cells" (PRT) using IFN-gamma enzyme-linked immunosorbent spot assays would evaluate independently cellular alloimmunity in transplant candidates. Peripheral blood lymphocytes from 41 hemodialysis patients who were awaiting first renal transplants were tested against a panel of allogeneic stimulator cells. Positive assays were defined arbitrarily as >25 spots/300,000 peripheral blood lymphocytes, and positive PRT was defined as when the responder reacted to 40 or 75% (PRT-75) of the stimulators. Seventeen percent of patients were PRT-75+, whereas 32% were PRA+. Twelve percent of the cohort was PRT-75+/PRA-, and only 5% of the patients were PRA+/PRT-75+, indicating that T cell alloreactivity did not routinely imply B cell sensitization and vice versa. PRT-75+ patients were more likely to be younger (<55 yr) and black. In contrast, a positive PRA was significantly associated with female gender but not race or age. Pretransplantation screening of cellular alloimmunity by enzyme-linked immunosorbent spot-based PRT detects a subset of hemodialysis patients who differ from those that are PRA+. Preliminary correlations with posttransplantation outcome in seven recipients suggest that PRT screening has the potential to aid in risk assessment in renal transplant candidates.     

Inflammatory colitis: classification and surgical treatment

The development of clinical and histopathological criteria for the diagnosis of Crohn's disease (CD) and ulcerative colitis (UC), pushed the scientists to identify a new category: the indeterminate colitis (CI). This term is used when definitive diagnosis of UC or CD has not been made by colonoscopy, colonic biopsy or colectomy. The distinction between these forms has major implications including the choice of medical treatment, timing of surgery, prognosis and disease course. The role of surgery in inflammatory bowel disease differs between the three main forms: in CD is primarily to treat complications of the disease process; in UC surgery is curative for intestinal manifestations and nearly eliminates the risk of future malignancy; in IC is actually discussed: the current guidelines identify in surgery the best treatment for fulminate disease, intractability of disease symptoms or failure of medical therapy. Although there is a few number of studies in the literature, selective criteria for the diagnosis and successful treatment must be revisited. The term CI should be used as a pending tray diagnosis, representing diagnostic inadequacy and not as specific nosological entity. Evidence emerging from the studies of serological markers (ASCA and P-ANCA) suggests that a subgroup of patients initially diagnosed as IC maybe identified as a separate group, and so they need a specific treatment for their disease.     

Calcineurin inhibitors, but not rapamycin, reduce percentages of CD4+CD25+FOXP3+ regulatory T cells in renal transplant recipients

BACKGROUND: Immunosuppression in renal transplantation, although manageable in the short-term, is a major hurdle for long-term graft survival. Recently, increased frequencies of CD4CD25 regulatory T cells (Tregs) have been described as an additional mechanism that induces alloimmune tolerance. METHODS: We assessed 64 renal transplant recipients with stable renal function for at least one year. Patients were divided into two groups according to the immunosuppression they were receiving at the moment of the study: one consisted of patients receiving rapamycin (Rapa) but not calcineurin inhibitors (CNI), and the other group received CNI but not Rapa. The Rapa group was further divided into three subgroups according to their previous experience with CNI: CNI-free, CNI withdrawal, and CNI conversion. Frequencies of blood Tregs were studied by flow cytometry after staining with monoclonal antibodies specific for different markers of Tregs. RESULTS: Frequencies of CD4 T cells with regulatory phenotype and function were significantly decreased in peripheral blood of renal transplant patients receiving CNI compared with those receiving Rapa. This effect was independent of an early exposure to CNI because the CNI-free patients in the Rapa group showed similar frequencies of Tregs to the CNI withdrawal and CNI conversion groups. CONCLUSIONS: CNI, but not Rapa, induce a decrease of circulating Tregs in stable renal transplant recipients. Thus, Rapa might be further explored in strategies using preservation of Tregs for transplant tolerance. Furthermore, quantification of blood Tregs may be a suitable tool to identify renal transplant recipients who may be candidates for reduced immunosuppression.