INSULIN AUTOIMMUNE SYNDROME IN A YOUNG CAUCASIAN WOMAN.

A young Caucasian woman presents several episodes of severe fasting hypoglycemia. Fasting lab tests revealed: glycemia 28 mg/dL, insulinemia 143.3 µU/mL, insulin antibodies above 100 U/mL, leading to the diagnosis of insulin autoimmune syndrome. Due to lack of clinical improvement after 2 months, prednisone was started at 0.5 mg/kg/day, and then tapered by 5 mg every 5 days. Three weeks after discontinuing corticotherapy, the patient had no more severe fasting hypoglycemia, but occasionally postprandial mild hypoglycemia. Fasting lab tests showed: glycemia 83 mg/dL, insulinemia 58.6 µU/mL. At 5 hours during oral glucose tolerance test glycemia was 33 mg/dL, insulinemia 152.9 µU/mL.

Prognostic significance and detection of the internal tandem duplication of the FLT3 gene in acute myeloid leukemia.

The FMS-like tyrosine kinase-3 (FLT3), which belongs to the class III receptor tyrosine kinase family, expressed by immature hematopoietic cells, plays an important role in the proliferation, differentiation and survival of stem cells. The activating mutations of FLT3 gene have been reported to be of prognostic significance. The most common somatic alteration of the FLT3 gene is the Internal Tandem Duplication (FLT3/ITD), which is caused by the elongation of the juxtamembrane (JM) domain of FLT3. The duplicated fragment size varies from 3 to more than 400 base pair, always occurs in multiples of three while the reading frame is preserved. The elongated segment of DNA can be amplified by polymerase chain reaction (PCR), and the products are separated by gel electrophoresis. The FLT3/ITD is found in 20-40% of adult AML patients and is the most frequent mutation in leukemia. Using native peripheral blood and bone marrow from AML and non-AML patients (total of 19 samples), and samples from the RNA bank (total of eight samples), the authors purpose was to work out a method for FLT3/ITD detection, which can be used in routine diagnostics. All samples produced detectable PCR products, which proofs that this procedure can be used for the detection of FLT3/ITD mutations in daily clinical practice.

Relationship between the mutational status of VH genes and pathogenesis of diffuse large B-cell lymphoma in Richter's syndrome.

Patients with chronic lymphocytic leukemia (CLL) may develop diffuse large B-cell lymphoma (DLBL), also known as Richter's syndrome. Mutational status of immunoglobulin (Ig) heavy-chain variable region (VH) genes have prognostic impact in CLL. Patients with mutated VH genes have a stable disease, whereas patients with unmutated VH gene have more aggressive disease. The mutational status of CLLs that transform to DLBL is unknown. To reveal whether Richter's syndrome occurs in CLLs with mutated or unmutated VH genes, we have performed mutational analysis on serial specimens from eight patients. CLL and DLBL tumorclones were identical in five cases and they were different in three cases. Six CLLs expressed unmutated and two cases expressed mutated VH genes. In five of the six unmutated CLLs, the DLBL clones evolved from CLL tumorclones and the VH genes expressed by DLBLs were also unmutated. In one unmutated and two mutated CLLs, the DLBLs expressed mutated VH genes, but in these three cases the DLBL tumorclones developed as independent secondary neoplasm. These results suggest that Richter's syndrome may develop in both mutated or unmutated CLLs, but clonal transformation of CLL to DLBL occur only in the unmutated subgroup of CLL.

Microsatellite instability and hMLH1 promoter hypermethylation in Richter's transformation of chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is an indolent B cell non-Hodgkin lymphoma (NHL) that may transform into diffuse large B cell lymphoma (DLBL). This transformation is referred to as Richter's syndrome or transformation. To analyze whether microsatellite instability (MSI) and DNA mismatch repair defects are associated with Richter's transformation, we have performed microsatellite analysis, mutational analysis of hMLH1 and hMSH2 genes and methylation status analysis of CpG island of the hMLH1 promoter on serial biopsy specimens from 19 patients with CLL. Ten cases of CLL showed no histologic alteration in the second biopsy, and nine cases of CLL underwent morphologic transformation to DLBL in the second biopsy. Using eight microsatellite loci, high level of MSI was associated with Richter's transformation in four cases of CLL, but none of the CLLs displayed this level of MSI without transformation. Mutations of the hMLH1 or hMSH2 genes were not detected in any of the lymphoma samples. In five cases of Richter's transformation the hMLH1 promoter was hypermethylated in both CLL and DLBL samples. Hypermethylation of the hMLH1 promoter associated with high-level of MSI in four cases, and low-level of MSI in one case. These results suggest that in certain cases of Richter's transformation the DNA mismatch-repair defect-initiated genetic instability may play a role in tumor progression.

Adaptation of Sprague Dawley rats to long-term feeding of high fat or high fructose diets.

BACKGROUND: Present animal models used to emulate type 2 diabetes may not accurately reflect the metabolic changes that occur in humans. AIM OF THE STUDY: The purpose of this research was to evaluate diets reported to induce insulin resistance and impaired glucose metabolism in rats as a potentially useful model for studying type 2 diabetes. METHODS: Three groups of male Sprague Dawley rats (n=7) were fed either a control diet, based on AIN recommendations (53% cornstarch, 10% sucrose and 7% soybean oil), a high fat diet (25% soybean oil, 35% cornstarch) or a high fructose diet (53% fructose, 10% sucrose) for a 3 month period. Glucose tolerance tests were carried out in week 3 and week 9 of the experiment. At the termination of the experiment, serum insulin, glucose, cholesterol and triacylglycerols were measured. Glucose incorporation into glycogen and glycogen synthase activity were measured in soleus muscles. RESULTS: Similar weight gain was observed for all three groups of rats. Glucose tolerance curves and fasting glucose levels were not significantly different at any time point in the experiment. Insulin levels were unchanged for the controls (171+/-21 pM), high fructose (164+/-16 pM) and high fat (181+/-30 pM) diets. Fasting serum triacylglycerols and cholesterol levels were not significantly elevated by dietary treatment. In soleus muscles, rats on all three diets had a significant increase in glycogen synthesis in response to insulin, but synthesis was similar in all three groups. Glycogen synthase activity was also not significantly affected by long-term dietary intervention. CONCLUSIONS: In this study, healthy Sprague Dawley rats fed high fat or high fructose diets for 3 months adapted to the nutritional intervention without developing classical signs of insulin resistance and impaired glucose tolerance.

Genetic instability is associated with histological transformation of follicle center lymphoma.

Follicle center lymphoma (FCL) is an indolent B cell non-Hodgkin's lymphoma (NHL) characterized genetically by the t(14;18) translocation. Histological transformation and clinical progression of FCLs are frequently associated with secondary genetic alterations at both nucleic acid and chromosomal levels. To determine the type and pattern of genomic instability occurring in histological transformation of FCLs and the role of DNA mismatch repair defects in this procedure, we have performed microsatellite analysis, comparative genomic hybridization (CGH) and mutational analysis of hMLH1 and hMSH2 genes on serial biopsy specimens from patients with FCL transformed to diffuse large cell lymphoma (DLCL). Paired biopsy samples of eight patients were analyzed for microsatellite instability and structural alterations for hMLH1 and hMSH2 genes, and tumor samples of five patients were subjected to CGH analysis. A high level of microsatellite instability was associated with histological transformation of two cases of FCL, but no mutations of the hMLH1 and hMSH2 genes were detected in any of the lymphoma samples. In the five cases subjected to CGH analysis, the histological transformation of FCLs was associated with genomic imbalances at 21 chromosomal regions. The genomic abnormalities found were rather heterogeneous and none of the genetic changes were overrepresented in the transformed DLCLs. These data suggest that histological transformation of FCLs to DLCL is frequently associated with genome wide instability at both nucleic acid and chromosomal levels, although mutations of the hMSH1 and hMLH2 genes are not involved in this process.

Effects of dietary fiber on the rat intestinal mucosa exposed to low doses of a carcinogen.

BACKGROUND: Changes in morphological and immunohistochemical parameters were studied in the rat intestinal mucosa exposed to low doses of a carcinogen and administered with dietary fibers. METHODS: Tumors were induced by five subcutaneous injections of 1,2-dimethylhydrazine, 10 mg/kg rat, once a week. Rats were fed a semi-synthetic fiber-free diet (control) or a high-fiber diets (15%) derived from cellulose, tomato peels or white grape. The rats were sacrificed 24 weeks after the first carcinogen's injection. The ileum, colon and tumors were removed for the study. Areas of the mucosal stroma and of lymph infiltrations, and mitotic index were studied along with morphological parameters. Immunohistochemical parameters included determination of Ki-67 proliferating protein and apoptotic index. RESULTS: Areas of the stroma in colon tumors increased in rats fed tomato peels. Changes in areas of lymphoid infiltrates were related to the type of diet and tumor presence. Lymphoid infiltrations were found to be highly developed in the colon area close to tumors, especially in rats fed the white-grape diet. Mitotic index and Ki-67 protein increased significantly in the colon area close to a tumor and in tumors themselves without any relation to the fiber varieties consumed. Changes in the rate of apoptosis were not related to the preventive effect of diets: apoptotic index was high in tumors obtained from rats fed the high-cellulose diet with high tumor-preventive effects and also from rats fed the high-tomato-peel diet with low tumor-preventive effects. CONCLUSIONS: No morphological changes were found in the ileum of rats exposed to a carcinogen and fed different dietary fibers. In the colon, a carcinogen even in low concentrations inhibited the lymphoid system in the mucosa located far from the tumor or close to the tumor. An increase in the proliferation rate in the colon close to the tumor may reflect the development of precanceromatous processes or may be related to the effect of growth factors expressed by tumor cells. Finding adenoma-like dysplasia near tumors may be possible in early stages of the development of new tumors. In addition, activation of the lymphoid system of the colon following consumption to specific dietary fiber may be a mechanism by which fiber protect against cancer.

Tumor-promoting and tumor-protective effects of high-fat diets on chemically induced mammary cancer in rats.

We studied the effects of different dietary fats on experimental rat mammary lumorigenesis induced by 9,10-dimethyl-1, 2-benzanthracene (DMBA). Rats were randomly placed into four groups fed different diets: a chow diet, and high-fat (15%) diets derived from avocado, soybean or olive oils. The rats were killed 12 weeks after treatment with DMBA (a single dvse of 10 mg/rat) and maintenance on these diets. The olive diet was associated with a significant reduction in the tumorigenic effect of DMBA: tumor incidence decreased to 30%, as compared to 44%-55% in the other dietary groups studied (p < 0.05). The protective antitumor effect of the olive diet was found to be connected to its dietary content of monounsaturated fatty acids such as oleic and palmitic acids and with serum concentrations of stearic acid. The promotive tumorigenic effects of the other high-fat diets were associated with their high levels of some polyunsaturated fatty acids (linoleic and alinolenic). Malignant mammary tissue exhibited higher values than benign tissue for all the argyrophilic-nucleolar-organizer region parameters measured. The tumor-associated protein p53 was accumulated to high levels in the blood of tumor-bearing rats, but not in that of the non tumor-bearing rats.

Effects of high-fiber diets on pathological changes in DMH-induced rat colon cancer.

The protective role of dietary fibers on tumorigenic effects of 1,2-dimethylhydrazine (DMH) on the rat colon was studied using histochemical, immunohistochemical, and biochemical analyses. Rats were injected with DMH (20 mg/kg sc) for five weeks, once a week, and were fed laboratory chow (Control I), semisynthetic fiber-free diet (Control II), or 18% or 25% assorted fiber (cellulose, beans, corn) diet. The rats were sacrificed 12, 16, and 24 weeks after the carcinogenic injections. Adenomatous tumors developed in 90-100% of the animals fed chow or fiber-free diets. A diet with high concentrations (25%) of corn dietary fiber significantly decreased the tumor incidence (40% and 42%) and tumor yield (p < 0.01). Diets with lower concentrations of fibers (18%) did not protect against tumorigenic effects of DMH. No differences were found in pathological parameters of tumors obtained from different dietary groups: the damage index (percentage of damaged cells per section) was very similar in all groups studied. Diets enriched with dietary fibers (25%) had a significant protective effect in DMH-induced rat colon cancer.