Remote and local drivers of Pleistocene South Asian summer monsoon precipitation: A test for future predictions

South Asian precipitation amount and extreme variability are predicted to increase due to thermodynamic effects of increased 21st-century greenhouse gases, accompanied by an increased supply of moisture from the southern hemisphere Indian Ocean. We reconstructed South Asian summer monsoon precipitation and runoff into the Bay of Bengal to assess the extent to which these factors also operated in the Pleistocene, a time of large-scale natural changes in carbon dioxide and ice volume. South Asian precipitation and runoff are strongly coherent with, and lag, atmospheric carbon dioxide changes at Earth's orbital eccentricity, obliquity, and precession bands and are closely tied to cross-equatorial wind strength at the precession band. We find that the projected monsoon response to ongoing, rapid high-latitude ice melt and rising carbon dioxide levels is fully consistent with dynamics of the past 0.9 million years.

Hypoxia-associated markers in gastric carcinogenesis and HIF-2alpha in gastric and gastro-oesophageal cancer prognosis

The study investigated hypoxia-associated markers (HIF-2α, Epo, Epo-R, Glut-1 and VEGF) along with Ki-67 in a gastric carcinogenesis model, and the prognostic significance of hypoxia-inducible factor (HIF)-2α in surgically treated gastro-oesophageal cancer. Protein expression was examined using immunohistochemistry on formalin-fixed, paraffin-embedded biopsies of normal mucosa (n=20), Helicobacter pylori-associated gastritis (n=24), intestinal metaplasia (n=24), dysplasia (n=12) and intestinal (n=19) and diffuse (n=21) adenocarcinoma. Relationships between HIF-2α expression and prognosis were assessed in resection specimens from 177 patients with gastric and gastro-oesophageal junction adenocarcinoma. Expression of all markers increased with progression along the gastric carcinogenesis sequence (P=0.0001). Hypoxia-inducible factor-2α was expressed in 63% of 177 resection specimens and at a high level in 44%. The median overall survival in patients with HIF-2α-expressing tumours was 22 (95% CI 18−26) months, whereas those with HIF-2α-negative tumours had a median survival of 37 (95% CI 29−44) months (P=0.015). Hypoxia-inducible factor-2α had no independent prognostic significance in multivariate analysis. In view of the lack of independent prognostic significance, HIF-2α has no role as a routine prognostic indicator. However, the high expression of HIF-2α suggests that it may be of value as a potential therapeutic target.

Increasing expression of hypoxia-inducible proteins in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence

Hypoxia-associated markers are involved in the progression of several malignancies, but are relatively unstudied in Barrett's carcinogenesis. Our aim was to assess the immunohistochemical expression of hypoxia-inducible factor (HIF)-1α, HIF-2α, erythropoietin (Epo), Epo receptor (Epo-R), Glut-1 and vascular endothelial growth factor (VEGF) along with Ki67/MIB-1 in the Barrett's metaplasia–dysplasia–adenocarcinoma sequence. Endoscopic biopsies of normal squamous epithelium (NSE) (n=20), columnar-lined oesophagus (CLO) (n=15), CLO with intestinal metaplasia (n=20), dysplasia (n=17) and Barrett's type adenocarcinoma (n=20) were obtained. Immunohistochemistry was performed on the paraffin-embedded tissue. A score was calculated for each marker (range 0−300) by multiplying intensity (none 0, weak 1, moderate 2, strong 3) by percentage of expression (range 0–100). Significant increases in the expression of HIF-2α (P=0.014), VEGF (P<0.0001), Epo-R (P<0.0001) and Ki67 (P<0.0001) were found as tissue progressed from NSE to adenocarcinoma. HIF-2α was expressed late in the sequence and was only seen in dysplasia and adenocarcinoma. High HIF-2α expression was seen in 12 out of 20 Barrett's type adenocarcinoma. The late expression of HIF-2α in the Barrett's carcinogenesis sequence and its high expression in adenocarcinoma suggest that it is worth further investigation as a marker of disease progression and therapeutic target.

TEL/PDGFbetaR induces hematologic malignancies in mice that respond to a specific tyrosine kinase inhibitor

The TEL/PDGFbetaR fusion protein is expressed as the consequence of a recurring t(5;12) translocation associated with chronic myelomonocytic leukemia (CMML). Unlike other activated protein tyrosine kinases associated with hematopoietic malignancies, TEL/PDGFbetaR is invariably associated with a myeloid leukemia phenotype in humans. To test the transforming properties of TEL/PDGFbetaR in vivo, and to analyze the basis for myeloid lineage specificity in humans, we constructed transgenic mice with TEL/PDGFbetaR expression driven by a lymphoid-specific immunoglobulin enhancer-promoter cassette. These mice developed lymphoblastic lymphomas of both T and B lineage, demonstrating that TEL/PDGFbetaR is a transforming protein in vivo, and that the transforming ability of this fusion is not inherently restricted to the myeloid lineage. Treatment of TEL/PDGFbetaR transgenic animals with a protein tyrosine kinase inhibitor with in vitro activity against PDGFbetaR (CGP57148) resulted in suppression of disease and a prolongation of survival. A therapeutic benefit was apparent both in animals treated before the development of overt clonal disease and in animals transplanted with clonal tumor cells. These results suggest that small-molecule tyrosine kinase inhibitors may be effective treatment for activated tyrosine kinase-mediated malignancies both early in the course of disease and after the development of additional transforming mutations.

Trends in organ donation

Renal and extrarenal transplant data were collected for seven geographical regions for the period 1989-1996. In Western Europe and North America the number of kidney donors increased by 926 and 2743, respectively. The total number of transplants also increased in both regions by 3756 and 6936, respectively. Renal transplants accounted for approximately 60% of the total number of transplants and, although the number of renal transplants did not alter in Western Europe, the number rose by 3055 in North America. Outside of these regions the number of extrarenal transplants was 3-18% of the total. The number of living kidney donors in North America increased each year and was higher than the number recruited in Western Europe (3389 vs 943 in 1996). With the exception of Eastern Europe, where virtually no renal transplants were carried out using organs from living donors, the number of living kidney donors rose in other regions: for example, in Latin America, the proportion of living kidney donors rose from 29% in 1970-88 to 51% in 1995, and, in Asia, 90% of kidneys were donated by living donors. As the quality of cadaveric donor organs is often sub-optimal, the use of living donors is likely to increase in both Western Europe and North America, but is unlikely to become the most important source of organs in these regions.