Characterization of Non-hormone Expressing Endocrine Cells in Fetal and Infant Human Pancreas

Context: Previously, we identified chromograninA positive hormone-negative (CPHN) cells in high frequency in human fetal and neonatal pancreas, likely representing nascent endocrine precursor cells. Here, we characterize the putative endocrine fate and replicative status of these newly formed cells.Objective: To establish the replicative frequency and transcriptional identity of CPHN cells, extending our observation on CPHN cell frequency to a larger cohort of fetal and infant pancreas.Design, Setting, and Participants: 8 fetal, 19 infant autopsy pancreata were evaluated for CPHN cell frequency; 12 fetal, 24 infant/child pancreata were evaluated for CPHN replication and identity.Results: CPHN cell frequency decreased 84% (islets) and 42% (clusters) from fetal to infant life. Unlike the beta-cells at this stage, CPHN cells were rarely observed to replicate (0.2 ± 0.1 vs. 4.7 ± 1.0%, CPHN vs. islet hormone positive cell replication, p < 0.001), indicated by the lack of Ki67 expression in CPHN cells whether located in the islets or in small clusters, and with no detectable difference between fetal and infant groups. While the majority of CPHN cells express (in overall compartments of pancreas) the pan-endocrine transcription factor NKX2.2 and beta-cell specific NKX6.1 in comparable frequency in fetal and infant/child cases (81.9 ± 6.3 vs. 82.8 ± 3.8% NKX6.1+-CPHN cells of total CPHN cells, fetal vs. infant/child, p = 0.9; 88.0 ± 4.7 vs. 82.1 ± 5.3% NKX2.2+-CPHN cells of total CPHN cells, fetal vs. infant/child, p = 0.4), the frequency of clustered CPHN cells expressing NKX6.1 or NKX2.2 is lower in infant/child vs. fetal cases (1.2 ± 0.3 vs. 16.7 ± 4.7 clustered NKX6.1+-CPHN cells/mm2, infant/child vs. fetal, p < 0.01; 2.7 ± 1.0 vs. 16.0 ± 4.0 clustered NKX2.2+-CPHN cells/mm2, infant/child vs. fetal, p < 0.01).Conclusions: The frequency of CPHN cells declines steeply from fetal to infant life, presumably as they differentiate to hormone-expressing cells. CPHN cells represent a non-replicative pool of endocrine precursor cells, a proportion of which are likely fated to become beta-cells.Precis: CPHN cell frequency declines steeply from fetal to infant life, as they mature to hormone expression. CPHN cells represent a non-replicative pool of endocrine precursor cells, a proportion of which are likely fated to become beta-cells

Age at first childbirth and oral contraceptive use are associated with risk of androgen receptor-negative breast cancer: the Malmö Diet and Cancer Cohort.

Risk factors for breast cancer vary according to breast cancer subtype. This study analyzes the impact of potential risk factors in breast cancer by androgen receptor (AR) status

The quality of preventive health care delivered to adults: results from a cross-sectional study in Southern Italy

<p>Abstract</p> <p>Background</p> <p>It is assumed that providing clinical preventive services to patients can identify or detect early important causes of adult mortality. The aim of this study was to quantify access to preventive services in Southern Italy and to assess whether and how the provision of preventive care was influenced by any specific characteristics of patients.</p> <p>Methods</p> <p>In a cross-sectional study adults aged 18 years and over attending primary care physician (PCP) offices located in Southern Italy were interviewed from June through December 2007. Quality indicators of preventive health care developed from RAND's Quality Assessment Tools and Behavioral Risk Factor Surveillance System (BRFSS) were used. Multivariate analysis was performed to identify and to assess the role of patients' characteristics on delivery of clinical preventive services.</p> <p>Results</p> <p>A total of 1467 subjects participated in the study. Excepting blood pressure preventive check (delivered to 64.4% of eligible subjects) and influenza vaccination (recommended to 90.2% of elderly), the rates of delivery of clinical preventive services were low across all measures, particularly for screening and counseling on health habits. Rates for providing cancer screening tests at recommended times were 21.3% for colonoscopy, 51.5% for mammography and 52.4% for Pap smear. Statistical analysis showed clear disparities in the provision of clinical preventive services associated with age, gender, education level, perceived health status, current health conditions and primary care access measures.</p> <p>Conclusions</p> <p>There is overwhelming need to develop and implement effective interventions to improve delivery of routine clinical preventive services.</p

Towards an optimal sampling strategy for assessing genetic variation within and among white clover (Trifolium repens L.) cultivars using AFLP

Cost reduction in plant breeding and conservation programs depends largely on correctly defining the minimal sample size required for the trustworthy assessment of intra- and inter-cultivar genetic variation. White clover, an important pasture legume, was chosen for studying this aspect. In clonal plants, such as the aforementioned, an appropriate sampling scheme eliminates the redundant analysis of identical genotypes. The aim was to define an optimal sampling strategy, i.e., the minimum sample size and appropriate sampling scheme for white clover cultivars, by using AFLP data (283 loci) from three popular types. A grid-based sampling scheme, with an interplant distance of at least 40 cm, was sufficient to avoid any excess in replicates. Simulations revealed that the number of samples substantially influenced genetic diversity parameters. When using less than 15 per cultivar, the expected heterozygosity (He) and Shannon diversity index (I) were greatly underestimated, whereas with 20, more than 95% of total intra-cultivar genetic variation was covered. Based on AMOVA, a 20-cultivar sample was apparently sufficient to accurately quantify individual genetic structuring. The recommended sampling strategy facilitates the efficient characterization of diversity in white clover, for both conservation and exploitation

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

Use of [3-3H]glucose and [6-14C]glucose to measure glucose turnover and glucose metabolism in humans.

[3-3H]glucose is frequently used to measure glucose turnover in humans. If fructose 6-phosphate-fructose 1,6-diphosphate cycling (Fpc) is negligible in both liver and muscle, then [3-3H]- and [6-14C]glucose (corrected for Cori cycle activity) should provide equivalent measures of glucose turnover. In addition, if glycogenolysis is fully suppressed, then [14C]lactate specific activity should equal that of [6-14C]glucose from which it was derived, and oxidation of [6-14C]glucose, as measured by rate of generation of 14CO2, should equal total glucose oxidation (i.e., that derived from intra- and extracellular pools) as measured by indirect calorimetry. To address these questions, glucose turnover was measured simultaneously with [3-3H]- and [6-14C]glucose in the basal state and in presence of low (approximately 200 pM) and high (approximately 750 pM) insulin concentrations. Glucose turnover rates measured with [3-3H]- and [6-14C]glucose were equivalent at all insulin concentrations, indicating that Fpc had no detectable effect on measurement of glucose appearance. [14C]lactate specific activity was lower (P less than 0.01) than that of [6-14C]glucose in the basal state but not during either low- or high-dose insulin infusion, implying that all lactate was derived from extracellular glucose. On the other hand, glucose oxidation as measured by rate of generation of 14CO2 was lower (P less than 0.05) than glucose oxidation as measured by indirect calorimetry during both insulin infusions, implying either that suppression of glycogenolysis was not complete in all tissues or that one or both of these techniques do not accurately measure glucose oxidation.(ABSTRACT TRUNCATED AT 250 WORDS

Effects of pancreas transplantation on postprandial glucose metabolism.

BACKGROUND: Because a pancreas allograft is placed in the pelvis, pancreas transplantation abolishes the normal gradient between portal-vein and peripheral-vein insulin concentrations and causes systemic hyperinsulinemia. Whether pancreas transplantation restores carbohydrate metabolism to normal is not known. METHODS: We studied seven patients with insulin-dependent diabetes mellitus after pancreas-kidney transplantation, seven nondiabetic patients after kidney transplantation (to control for immunosuppression), and eight normal subjects. Measurements were made after an overnight fast and after ingestion of a mixed meal. RESULTS: Although plasma glucose concentrations did not differ in the two transplant groups, plasma insulin concentrations were significantly higher in the diabetic pancreas-kidney recipients than in the nondiabetic kidney recipients, both before the meal (mean +/- SE, 102 +/- 15 vs. 53 +/- 6 pmol per liter; P less than 0.05) and afterward (123 +/- 22 vs. 61 +/- 6 nmol per liter per six hours; P less than 0.05). Plasma C-peptide concentrations were the same in both groups, indicating that hyperinsulinemia was due to decreased insulin clearance rather than increased insulin secretion. Despite drainage of the venous effluent from the transplanted pancreas into the systemic circulation, the values for splanchnic clearance of ingested glucose, suppression of hepatic glucose release, incorporation of carbon dioxide into glucose, stimulation of glucose oxidation, glucose uptake, and forearm glucose clearance were all similar in the transplant groups and differed minimally from the values in the normal group. The similar rates of glucose uptake in the presence of higher systemic insulin concentrations indicated that the extrahepatic tissues of the diabetic pancreas-kidney recipients were insulin-resistant. CONCLUSIONS: Despite systemic delivery of insulin, pancreas-kidney transplantation in patients with diabetes results in carbohydrate metabolism similar to that in nondiabetic subjects receiving the same immunosuppressive agents after kidney transplantation