Quantitative analysis of (-)-N-(11)C-propyl-norapomorphine in vivo binding in nonhuman primates.

(-)-N-(11)C-propyl-norapomorphine ((11)C-NPA) is a new dopamine agonist PET radiotracer that holds potential for imaging the high-affinity states of dopamine D(2)-like receptors in the living brain. The goal of this study was to develop and evaluate analytic strategies to derive in vivo (11)C-NPA binding parameters. METHODS: Two baboons were scanned 4 times after (11)C-NPA injections. The metabolite-corrected arterial input functions were measured. Regional brain time-activity curves were analyzed with kinetic and graphical analyses, using the arterial time-activity curve as the input function. Data were also analyzed with the simplified reference-tissue model (SRTM) and graphical analysis with reference-region input. RESULTS: (11)C-NPA exhibited moderately fast metabolism, with 31% +/- 5% of arterial plasma concentration corresponding to the parent compound at 40 min after injection. Plasma clearance was 29 +/- 1 L/h, and plasma free fraction (f(1)) was 5% +/- 1%. For kinetic analysis, a 1-tissue compartment model (1TCM) provided a good fit to the data and more robust derivations of the tissue distribution volumes (V(T), in mL/g) than a 2-tissue compartment model (2TCM). Using 1TCM, V(T)s in the cerebellum and striatum were 3.4 +/- 0.4 and 7.5 +/- 2 mL/g, respectively, which led to estimates of striatal binding potential (BP) of 4.0 +/- 1.1 mL/g and striatal equilibrium specific-to-nonspecific partition coefficient (V(3)") of 1.2 +/- 0.2. V(T) values derived with graphical analysis were well correlated with but slightly lower than V(T) values derived with kinetic analysis. V(3)" values derived with SRTM were well correlated with but slightly higher than V(3)" values derived with kinetic analysis. Using any method, a significant difference was detected in BP and V(3)" values between the 2 animals. It was determined that 30 min of scanning data were sufficient to derive V(3)" values using kinetic, graphical (arterial input and reference-region input), and SRTM analyses. CONCLUSION: This study indicates that (11)C-NPA is a suitable PET tracer to quantify the agonist high-affinity sites of D(2)-like receptors.     

Prevention of N-methyl-N-nitrosourea-induced breast cancer by alpha-fetoprotein (AFP)-derived peptide, a peptide derived from the active site of AFP.

PURPOSE: alpha-Fetoprotein (AFP) is a protein of pregnancy associated with a decrease in lifetime risk of breast cancer in parous women. A synthetic, cyclic nonapeptide has been developed that mimics the antioncogenic active site of AFP. To test the hypothesis that the AFP-derived peptide (AFPep) can prevent breast cancer, the N-methyl-N-nitrosourea-induced breast cancer model was used in rats. EXPERIMENTAL DESIGN: AFPep was given daily by injection beginning 10 days after N-methyl-N-nitrosourea treatment and continued for 23 days (a time designed to mimic pregnancy) or for other times to assess efficacy as a function of drug duration. Tumor incidence, multiplicity, and latency were noted as end points. At necropsy, pathology analysis of tumors and major organs were obtained. RESULTS: AFPep prevented cancer in a dose-dependent fashion. Significantly longer mean tumor-free days (P < 0.02), lower tumor incidence (P = 0.004), and lower tumor multiplicity were observed for AFPep-treated groups. No evidence of host toxicity as measured by body weight, cage activity, fur texture, and organ weights (liver, uterus, heart, kidney, and spleen) were found in animals treated with AFPep. Mechanistic studies using transplantable human breast cancer xenografts showed that the peptide interfered with estrogen-dependent breast cancer growth inhibited the phosphorylation of the estrogen receptor and activated phosphorylation of p53. CONCLUSIONS: AFPep is a well-tolerated, mechanistically novel, chemopreventive agent in models of breast cancer and warrants further development for the prevention and treatment of this disease in humans.     

Expression analysis of cystatin C and M in laser-capture microdissectioned human breast cancer cells--a preliminary study

Cathepsins B and L, implicated in the progression of malignant tumors, are regulated by a family of endogenous inhibitors referred to as the cystatins. Cystatin M was identified by differential display as down-regulated gene in metastatic breast cancer cells. However, this finding has yet to be confirmed in clinical breast cancer specimens. Our objective is to examine the expression levels of cystatins C, M, and cathepsins B and L mRNA in breast cancer cells isolated by laser capture microdissection. The mRNA and protein levels of cathepsin B, L, and cystatin C and M in breast cancer specimens were determined utilizing laser capture microdissection/RT-PCR, Western blotting, and immunohistochemical methods. Expression levels of either cystatin M or C were not significantly different between lymph node-positive and -negative breast carcinomas. Increased expression levels of both cystatin M and C correlated significantly with larger tumor size. Cystatin M mRNA was detected by in situ hybridization in both primary and metastatic breast cancer cells. Our findings are at variance with a previous report proposing a metastasis suppressive function for cystatin M. Therefore, additional studies in a larger series with adequate follow-up are necessary to elucidate the biologic significance of cystatin M expression in breast cancer metastasis.     

Molecular and phenotypic diversity of CBLmutated juvenile myelomonocytic leukemia

Mutations in the CBL gene were first identified in adults with various myeloid malignancies. Some patients with juvenile myelomonocytic leukemia (JMML) were also noted to harbor mutations in CBL, but were found to have generally less aggressive disease courses compared to patients with other forms of Ras pathway-mutant JMML. Importantly, and in contrast to most reports in adults, the majority of CBL mutations in JMML patients are germline with acquired uniparental disomy occurring in affected marrow cells. Here, we systematically studied a large cohort of 33 JMML patients with CBL mutations and found that this disease is highly diverse in presentation and overall outcome. Moreover, we discovered somatically acquired CBL mutations in 15% of pediatric patients who presented with more aggressive disease. Neither clinical features nor methylation profiling were able to distinguish patients with somatic CBL mutations from those with germline CBL mutations, highlighting the need for germline testing. Overall, we demonstrate that disease courses are quite heterogeneous even among patients with germline CBL mutations. Prospective clinical trials are warranted to find ideal treatment strategies for this diverse cohort of patients.     

Mannose binding lectin gene variants and susceptibility to tuberculosis in HIV-1 infected patients of South India

Mannose binding lectin (MBL) plays an important role in innate immunity. Plasma MBL levels and MBL2 gene polymorphisms were studied in HIV-1 infected patients without tuberculosis (HIV+TB-) (n=151) and with tuberculosis (HIV+TB+) (n=109), HIV negative tuberculosis patients (HIV-TB+) (n=148) and healthy controls (n=146) by ELISA and genotyping by polymerase chain reaction based methods. MBL levels were significantly increased among HIV-TB+ and HIV+TB+ patients than controls and HIV+TB- patients (P<0.05). A significantly increased frequency of OO genotype of structural polymorphism and YY genotype of -221Y/X was observed among HIV-TB+ patients than controls. In HIV+TB+ patients, a significantly increased frequency of YA/YA diplotype (associated with very high MBL levels) was observed compared to controls (P=0.03). In HIV+TB+ patients, a significantly decreased frequency of medium MBL expression diplotypes (XA/XA and YA/YO) were noticed compared to HIV+TB- and healthy controls. The results suggest that YA/YA diplotype associated with very high MBL levels may predispose HIV-infected patients to tuberculosis while O/O genotype associated with very low MBL levels may be associated with susceptibility to tuberculosis in HIV uninfected individuals. Medium MBL expression diplotypes might protect against development of TB in HIV-infected patients.     

Relationship of dental caries and fluorosis to fluoride supplement history in a non-fluoridated sample of schoolchildren

A random sample of 206 Michigan children, aged from 9 to 13, were examined for fluorosis from a larger group of 2038 children participating in a dental project. Clinical examinations included caries data (DMFS) and assessment of fluorosis by use of the Tooth Surface Index of Fluorosis (TSIF). Separate examiners were used for each index. The response rate of a questionnaire mailed to parents to gather information on residence histories, use of fluoride supplements, and antibiotics was 78%. The prevalence of fluorosis was about 20% among the respondents. Of the 4868 tooth surfaces examined, 9.2% were affected by fluorosis. In all cases, dental fluorosis was judged as mild, with most occurrences on the posterior teeth. No instances of moderate or severe fluorosis were found. The caries experience of respondents was 1.69 +/- 2.73 DMFS. Caries experience does not appear to be significantly related to income, education, or fluoride supplement use. Approximately 52% of respondents were reported to have taken fluoride supplements with various degrees of consistency. Parents' education was positively related to both prevalence of fluorosis (odds ratio = 2.2) and use of fluoride supplements (odds ratio = 2.7). No significant relation was revealed with evidence of fluorosis and use of supplements. This study shows a relatively mild level of dental fluorosis in a sample of children from a non-fluoridated area. Dental fluorosis in this group does not appear to be related to use of fluoride supplements or differences in caries experience.