Investigation of diachronic dietary patterns on the islands of Ibiza and formentera, Spain: Evidence from carbon and nitrogen stable isotope ratio analysis

To examine how dietary patterns may have changed in the western Mediterranean through time, stable carbon and nitrogen isotope ratios were measured on extracted bone collagen from fauna (n = 75) and humans (n = 135) spanning four distinct chronological periods: Chalcolithic (c.2100–1600 BC), Punic (6th–2nd/1st century BC), Late Antiquity‐Early Byzantine (4th–7th century AD), and Islamic (c.10th–13th century AD) on the islands of Ibiza and Formentera, Spain. The Chalcolithic, Punic, and Late Antiquity‐Byzantine societies all showed evidence of a predominately C₃ terrestrial‐based diet with a possible input of a small amount of marine and/or C₄ dietary resources. In contrast, the Islamic population on Ibiza had a subsistence strategy that was reliant on a significant amount of C₄ plants and/or animals fed a C₄ diet, likely millet. These results indicate a fairly constant C₃ terrestrial‐based diet on the islands of Ibiza and Formentera through time, with a shift to C₄ dietary resources during the Islamic Period. Further research is needed from other Islamic populations in and around the Mediterranean to better understand this unique dietary adaptation. Am J Phys Anthropol 143:512–522, 2010. © 2010 Wiley‐Liss, Inc.     

The US distribution of physicians from lower income countries

Introduction

Since the 1960 s, the number of international medical graduates (IMGs) in the United States has increased significantly. Given concerns regarding the effects of this loss to their countries of origin, the authors undertook a study of IMGs from lower income countries currently practicing in the United States.

Methods

The AMA Physician Masterfile was accessed to identify all 265,851 IMGs in active practice in the United States. These were divided by state of practice and country of origin. World Bank income classification was used to identify lower income countries.

Results

128,729 IMGs were identified from 53 lower income countries, constituting 15 percent of the US active physician workforce. As a percentage of the workforce, West Virginia (29%), New Jersey (27%), and Michigan (26%) had the most IMGs from lower income countries, and Montana, Idaho, and Alaska (all less than 2%), the least. The countries with the greatest loss of physicians to the United States per 100,000 population were the Philippines, Syria, Jordan, and Haiti.

Discussion

The reliance of US medicine on physicians from lower income countries is beneficial to the United States both clinically and economically. However, it results in a loss of the lower income country''s investment in the IMG''s education. We discuss possible mechanisms to compensate the lower income countries for the medical education costs of their physicians who immigrate to the US.     

Participation of the chaperone Hsc70 in the trafficking and functional expression of ASIC2 in glioma cells

High-grade glioma cells express subunits of the ENaC/Deg superfamily, including members of ASIC subfamily. Our previous work has shown that glioma cells exhibit a basally active cation current, which is not present in low-grade tumor cells or normal astrocytes, and that can be blocked by amiloride. When ASIC2 is present within the channel complex in the plasma membrane, the channel is rendered non-functional because of inherent negative effectors that require ASIC2. We have previously shown that high-grade glioma cells functionally express this current because of the lack of ASIC2 in the plasma membrane. We now hypothesize that ASIC2 trafficking in glioma cells is regulated by a specific chaperone protein, namely Hsc70. Our results demonstrated that Hsc70 co-immunoprecipitates with ASIC2 and that it is overexpressed in glioma cells as compared with normal astrocytes. In contrast, there was no difference in the expression of calnexin, which also co-immunoprecipitates with ASIC2. In addition, glycerol and sodium 4-phenylbutyrate reduced the amount of Hsc70 expressed in glioma cells to levels found in normal astrocytes. Transfection of Hsc70 siRNA inhibited the constitutively activated amiloride-sensitive current, decreased migration, and increased ASIC2 surface expression in glioma cells. These results support an association between Hsc70 and ASIC2 that may underlie the increased retention of ASIC2 in the endoplasmic reticulum of glioma cells. The data also suggest that decreasing Hsc70 expression promotes reversion of a high-grade glioma cell to a more normal astrocytic phenotype.     

Protein inhibitor of ornithine decarboxylase does not account for effect of putrescine on 3T3 cells

Putrescine and other amines are known to rapidly reduce or prevent increases in ornithine decarboxylase activity in a number of systems. We have confirmed reports of a nondialyzable inhibitor of the enzyme in serum-starved H-35 hepatoma cells exposed to serum and putrescine. In contrast, we detected little if any nondialyzable inhibitor in serum-limited Swiss 3T3 cells treated similarly. Also, evidence of a dissociable enzyme-inhibitor complex was found in H-35 cells but not in 3T3 cells. These results suggest that assimilated putrescine can reduce ornithine decarboxylase activity by mechanisms not involving a macromolecular inhibitor.     

Ca2+ transport and permeability in inside-out red cell membrane vesicles after freezing

To evaluate the effects of freezing and thawing on Ca2+ transport and permeability, inside-out red cell membrane vesicles (IORCMV) are examined. Exposure to the cryoprotectant Me2SO as well as different cooling regimes on unprotected and cryoprotected vesicles do not affect the membrane Ca2+ transport. However, freezing and thawing increase the membrane permeability to sucrose.     

The Histone Variant His2Av is Required for Adult Stem Cell Maintenance in the Drosophila Testis

Many tissues are sustained by adult stem cells, which replace lost cells by differentiation and maintain their own population through self-renewal. The mechanisms through which adult stem cells maintain their identity are thus important for tissue homeostasis and repair throughout life. Here, we show that a histone variant, His2Av, is required cell autonomously for maintenance of germline and cyst stem cells in the Drosophila testis. The ATP-dependent chromatin-remodeling factor Domino is also required in this tissue for adult stem cell maintenance possibly by regulating the incorporation of His2Av into chromatin. Interestingly, although expression of His2Av was ubiquitous, its function was dispensable for germline and cyst cell differentiation, suggesting a specific role for this non-canonical histone in maintaining the stem cell state in these lineages.