From the Cover: Ecosystem responses in the southern Caribbean Sea to global climate change

Over the last few decades, rising greenhouse gas emissions have promoted poleward expansion of the large-scale atmospheric Hadley circulation that dominates the Tropics, thereby affecting behavior of the Intertropical Convergence Zone (ITCZ) and North Atlantic Oscillation (NAO). Expression of these changes in tropical marine ecosystems is poorly understood because of sparse observational datasets. We link contemporary ecological changes in the southern Caribbean Sea to global climate change indices. Monthly observations from the CARIACO Ocean Time-Series between 1996 and 2010 document significant decadal scale trends, including a net sea surface temperature (SST) rise of ∼1.0 ± 0.14 °C (±SE), intensified stratification, reduced delivery of upwelled nutrients to surface waters, and diminished phytoplankton bloom intensities evident as overall declines in chlorophyll a concentrations (ΔChla = −2.8 ± 0.5%⋅y⁻¹) and net primary production (ΔNPP = −1.5 ± 0.3%⋅y⁻¹). Additionally, phytoplankton taxon dominance shifted from diatoms, dinoflagellates, and coccolithophorids to smaller taxa after 2004, whereas mesozooplankton biomass increased and commercial landings of planktivorous sardines collapsed. Collectively, our results reveal an ecological state change in this planktonic system. The weakening trend in Trade Winds (−1.9 ± 0.3%⋅y⁻¹) and dependent local variables are largely explained by trends in two climatic indices, namely the northward migration of the Azores High pressure center (descending branch of Hadley cell) by 1.12 ± 0.42°N latitude and the northeasterly progression of the ITCZ Atlantic centroid (ascending branch of Hadley cell), the March position of which shifted by about 800 km between 1996 and 2009.     

Irs2 Inactivation Suppresses Tumor Progression in Pten+/− Mice

Mutations in the phosphatase and tensin homologue (PTEN)/phosphatidylinositol-3 kinase-α (PI3K) signaling pathway are frequently found in human cancer. In addition, Pten^+/− mice develop tumors in multiple organs because of the activation of the PI3K signaling cascade. Because activation of PI3K signaling leads to feedback inhibition of insulin receptor substrate-2 (IRS2) expression, an upstream activator of PI3K, we therefore anticipated that IRS2 expression would be low in tumors that lack PTEN. Surprisingly, however, an elevation of IRS2 was often detected in tumor samples in which PTEN levels were compromised. To determine the potential contribution of Irs2 to tumor progression, Pten^+/− mice were crossed with Irs2^+/− mice. Deletion of Irs2 did not affect the initiation of neoplasia found in Pten^+/− mice but suppressed cancer cell growth, proliferation, and invasion through the basement membrane. Deletion of Irs2 also attenuated the expression of Myc in prostatic intraepithelial neoplasia in Pten^+/− mice. In addition, the expression levels of IRS2 and MYC were highly correlated in human prostate cancer, and IRS2 could stimulate MYC expression in cultured cells. Our findings provide evidence that the PI3K-activating adaptor Irs2 contributes to tumor progression in Pten^+/− mice by stimulating both Myc and DNA synthesis.     

Luminal dopamine modulates canine ileal water and electrolyte transport

Previous studies have suggested that dopamine stimulates active ileal ion absorption via ₂-adrenergic or dopaminergic receptor activation. Identification of a dopamine 1a receptor on rat enterocytes located in intestinal crypts prompted this investigation of the effect of luminally administered dopamine on water and ion transport in the canine ileum. Absorption studies (n=27) were performed in dogs with 25-cm ileal Thiry-Vella fistulas. Perfusion with [¹⁴C PEG was used to calculate absorption of water and electrolytes from the Thiry-Vella fistula. Experiments consisted of three 1-hr periods: basal, luminal drug infusion at 10^–4 M, and recovery. Agonists used included dopamine (DOP: -adrenergic, D₁ and D₂ receptor) and SKF 38393 (D₁ receptor). Antagonists used included terazosin (TZ: ₁) and yohimbine (YOH: ₂). DOP caused significant increases in water and electrolyte absorption. TZ and YOH prevented the dopamine-induced proabsorptive response. Luminal DOP may serve as a proabsorptive modulator of ileal transport, acting via ₁, ₂, and dopaminergic receptors. The development of more potent proabsorptive dopamine analogs, which maintain the ability to broadly activate mucosal receptors, may be useful in such clinical situations as diabetic diarrhea, short gut syndrome, or following small bowel transplantation.Presented in part as a poster presentation at the Annual Meeting of the American Gastroenterological Association, New Orleans, May 14–18, 1994, and published in abstract form inGastroenterology 106:A432, 1994.Supported in part by National Institutes of Health grant R29-DK 41178 (C.J.Y.).     

Cardiac arrest and left ventricular fibrosis in a Finnish family with the lamin A/C mutation

Introduction: We screened the candidate genes from a Finnish family in which the mother was resuscitated from ventricular fibrillation and the daughter died suddenly without any prior cardiac symptoms.
Methods and Results: In addition to screening of potential structural gene mutations, phenotyping of the proband and medico-legal autopsy of the victim of the sudden death, including histopathological examinations, were performed. Genetic screening revealed an R541C mutation in the lamin A/C gene both in the proband and her daughter. None of the 16 first- or second-degree relatives, or 96 unrelated healthy subjects, carried the same mutation. In the proband, the size and the global function of the left ventricle (LV) were normal, but a local hypokinesia and thinning of inferoposterior area of the LV were seen in 2D echocardiography and magnetic resonance imaging. Coronary angiogram and the results of the electrophysiological study were normal. Autopsy of the victim of sudden death showed localized thinning and fibrosis in the inferoposterior area of the LV, with only minimal fibrosis in the right ventricle and no abnormalities in the interventricular septum.
Conclusion: These observations indicate that a fatal or near-fatal cardiac arrhythmia can be the first clinical manifestation of a "de novo" mutation R541C of the lamin A/C gene. Replacement of cardiac myocytes by fibrosis seems to be the predominant pathologic-anatomic finding.     

Probability of liver cancer and survival in HCV-related or alcoholic-decompensated cirrhosis. A study of 377 patients.

BACKGROUND: Although chronic alcohol intake and chronic hepatitis C may progress to cirrhosis and hepatocellular carcinoma (HCC), few data are available about survival and probability of developing HCC in decompensated cirrhosis of both aetiologies. METHODS: This study identified factors related with probability of developing HCC and survival in a cohort of 377 consecutive patients with decompensated HCV-related cirrhosis (200 cases) or alcoholic cirrhosis (177 cases) without known HCC, hospitalized for their first hepatic decompensation, as well as to evaluate differences between both aetiologies. Patients were followed for a mean period of 39 +/- 2 months. RESULTS: During follow-up, 42 patients (11.1%) developed HCC (16.5% vs 5.1%) in groups HCV and alcohol, respectively; p = 0.0008), and 131 patients (34.7%) died (42% vs 26.6% in groups HCV and alcohol, respectively; p = 0.002). Age and HCV-cirrhosis were independently related to HCC development, while baseline age and Child-Turcotte-Pugh score were independently correlated with survival. CONCLUSION: Survival in decompensated HCV-related or alcoholic cirrhosis is influenced by age and baseline Child-Turcotte-Pugh score, without differences in cirrhosis aetiology. The risk of developing HCC is greater in HCV-related cirrhosis than in alcoholic cirrhosis.     

Anisakis simplex-induced small bowel obstruction after fish ingestion: preliminary evidence for response to parenteral corticosteroids.

BACKGROUND & AIMS: Gastrointestinal anisakiasis, a fish-borne zoonoses, may be acquired by humans after the ingestion of raw marine fish infested with larvae of the nematode Anisakis simplex. Because of the invasive nature of the parasite, inflammatory obstruction or perforation of the gut wall may result. Although rare, Anisakis-induced intestinal obstruction is becoming a growing public health problem in Mediterranean areas, such as Spain, with a high fish-intake-based diet. Unawareness of this entity and nonspecific clinical symptoms, along with the lack of alternative therapeutic options other than conservative measures, may explain why half of these patients require abdominal laparotomy for diagnostic and therapeutic purposes. METHODS: We describe a series of 8 patients with acute intestinal anisakiasis treated in our center from July 2001 to January 2004. RESULTS: The first 3 patients underwent segmental ileal resection for imminent peritonitis. The remaining 5 patients were treated with intravenous 6-methylprednisolone (1 mg/kg/24 h) for 5 days with fast clinical and radiologic resolution in all 5 patients with no adverse reactions. CONCLUSIONS: Although preliminary, our data may suggest that parenteral corticosteroids could be a reasonable, inexpensive, and safe alternative in these patients to prevent intestinal resection.