Giant cell arteritis presenting with annuloaortic ectasia

Four cases of giant cell arteritis causing severe aortic regurgitation secondary to an aneurysm of the ascending aorta are described. In two cases, the nature of the aortic pathology could be suspected considering the past clinical evidence of temporal arteritis and/or polymyalgia rheumatica. In the two other cases, the cardiothoracic manifestations represented the onset of Horton disease.     

Mucosal cell proliferation of the rectal stump in ulcerative colitis patients after ileorectal anastomosis

The proliferative activity and polyamine levels of the rectal epithelium in unoperated ulcerative colitis patients and in ulcerative colitis patients after total colectomy and ileorectal anastomosis were determined and compared with control subjects. Cell proliferation was evaluated in rectal biopsies by in vitro 3H thymidine incorporation by measuring the labeling index and the position of labeled cells along the crypt; polyamines were determined with a chromatographic method. In ulcerative colitis patients the labeling index was significantly increased, and labeled cells were shifted toward the upper part of the crypt when compared with controls. Ileorectal anastomosis patients showed a normalization of the labeling index and a distribution of labeled cells similar to controls. Polyamine levels were also increased in ulcerative colitis patients; in ileorectal anastomosis patients, the level of polyamines was decreased in respect to unoperated patients and return to normal values except for spermine. Because the increased proliferation and higher polyamine levels are related to increased colon cancer risk, our results confirm that ulcerative colitis is a risk factor for the development of carcinoma. Ileorectal anastomosis may reduce this risk through a normalization of mucosal cell proliferative activity and of some polyamine levels.     

Unaccounted CO2 leaks downstream of a large tropical hydroelectric reservoir

Recent studies show that tropical hydroelectric reservoirs may be responsible for substantial greenhouse gas emissions to the atmosphere, yet emissions from the surface of released water downstream of the dam are poorly characterized if not neglected entirely from most assessments. We found that carbon dioxide (CO₂) emission downstream of Kariba Dam (southern Africa) varied widely over different timescales and that accounting for downstream emissions and their fluctuations is critically important to the reservoir carbon budget. Seasonal variation was driven by reservoir stratification and the accumulation of CO₂ in hypolimnetic waters, while subdaily variation was driven by hydropeaking events caused by dam operation in response to daily electricity demand. This “carbopeaking” resulted in hourly variations of CO₂ emission up to 200% during stratification. Failing to account for seasonal or subdaily variations in downstream carbon emissions could lead to errors of up to 90% when estimating the reservoir’s annual emissions. These results demonstrate the critical need to include both limnological seasonality and dam operation at subdaily time steps in the assessment of carbon budgeting of reservoirs and carbon cycling along the aquatic continuum.

Inland waters play an important role in the sequestration, transport, and mineralization of carbon (1). Despite recent advances in our understanding of carbon cycling along the aquatic continuum (2–6), major uncertainties remain regarding the impact of human modifications to river hydrology, especially those stemming from large dams (7). Model carbon budgets have been constructed for many artificial reservoirs throughout the world (8); however, a lack of standardized methodologies and criteria for delimiting and attributing dam-driven carbon fluxes has generated biased and unclear metrics for carbon accounting (9). Given an ongoing dam construction boom for hydropower (10, 11), it is therefore an urgent priority to critically reassess carbon cycling within dammed rivers to better understand their role in the inland water carbon balance.Assessments of hydroelectric reservoir carbon dynamics routinely ignore the importance of “carbon leaks,” which arise when carbon released downstream of the dam exceeds the amounts received from inflows (12–16). This “leaked carbon” can be very large relative to other dam-associated carbon emissions, accounting for nearly 90% of the total emissions in one well-documented case in Malaysia (15) and for a substantial contribution (∼10–80%) in others (13, 14, 17). These few studies indicate that failure to measure carbon leaks may lead to fundamental misunderstanding of the role of dams and of hydropower development in the carbon biogeochemistry of rivers. There are two main factors that determine the CO₂ emissions downstream of dams: the concentration of dissolved CO₂ in discharged waters and turbulence (18). CO₂ concentration of discharged water is governed by the depth of the outflow in relation to reservoir stratification, which is seasonally dependent and typical in reservoirs with long-enough residence times (19). Turbulence determines the degree to which the water interacts with the atmosphere and therefore the speed at which gas equilibration is reached, i.e., it determines in part the gas-transfer velocity (18). Turbulence downstream links to dam discharge, which can vary substantially throughout the day depending on energy demand—a phenomenon known as “hydropeaking” (20). Given these different sources of variation, an ideal framework for estimating CO₂ leakage would address both subdaily (hourly) and seasonal-scale variations in discharge and CO₂ concentration.Here, we use a year-long dataset composed of high-frequency measurements of water temperature, pH, and conductivity in the Zambezi River to estimate CO₂ emissions downstream of Kariba Dam (Zambia) and compare them with a reference site upstream of Victoria Falls (upstream of Kariba Reservoir) to assess the relative importance of reservoir stratification and dam operations on downstream CO₂ emissions. We derived a rating curve to estimate hourly water velocity and depth from which we then calculated the gas transfer velocity [k₆₀₀, k_CO2 (21)] and subsequently the rate of CO₂ emission to the atmosphere (see Materials and Methods and SI Appendix). The combination of high-frequency measurements and long-term monitoring allowed us to assess the relative importance of reservoir stratification and dam operations on downstream CO₂ emissions and the magnitude of these emissions compared to other components of a conventional reservoir carbon budget.     

A randomized,controlled, delayed start trial of GM1 ganglioside in treated Parkinson's disease patients

The present single center, double-blind, delayed start study was conducted to examine possible symptomatic and disease-modifying effects of GM1 ganglioside in Parkinson's disease (PD). Seventy-seven subjects with PD were randomly assigned to receive GM1 for 120 weeks (early-start group) or placebo for 24 weeks followed by GM1 for 96 weeks (delayed-start group). Washout evaluations occurred at 1 and 2 years after the end of treatment. Seventeen additional subjects who received standard-of-care were followed for comparative information about disease progression. Primary outcome was change from baseline Unified Parkinson's Disease Rating Scale (UPDRS) motor scores. At week 24, the early-start group had significant improvement in UPDRS motor scores vs. a significant worsening of scores in the delayed-start group. The early-start group also showed a sustained benefit vs. the delayed-start group at week 72 and at week 120. Both groups had significant symptom worsening during washout. This study provides evidence that GM1 use for 24 weeks was superior to placebo for improving motor symptoms and that extended GM1 use (up to 120 weeks) resulted in a lower than expected rate of symptom progression. The data from this small study suggest that GM1 may have symptomatic and potentially disease modifying effects on PD.     

HLA class I sensitization in islet transplant recipients: report from the Collaborative Islet Transplant Registry

Pancreatic islet transplantation is a promising treatment option for patients severely affected with type 1 diabetes. This report from CITR presents pre- and posttransplant human leukocyte antigen (HLA) class I sensitization rates in islet-alone transplantation. Data came from 303 recipients transplanted with islet-alone between January 1999 and December 2008. HLA class I sensitization was determined by the presence of anti-HLA class I antibodies. Panel-reactive antibodies (PRA) from prior to islet infusion and at 6 months, and yearly posttransplant was correlated to measures of islet graft failure. The cumulative number of mismatched HLA alleles increased with each additional islet infusion from a median of 3 for one infusion to 9 for three infusions. Pretransplant PRA was not predictive of islet graft failure. However, development of PRA >20% posttransplant was associated with 3.6-fold (p < 0.001) increased hazard ratio for graft failure. Patients with complete graft loss who had discontinued immunosuppression had significantly higher rate of PRA ≥ 20% compared to those with functioning grafts who remained on immunosuppression. Exposure to repeat HLA class I mismatch at second or third islet infusions resulted in less frequent development of de novo HLA class I antibodies when compared to increased class I mismatch. The development of HLA class I antibodies while on immunosuppression is associated with subsequent islet graft failure. The risk of sensitization may be reduced by minimizing the number of islet donors used per recipient, and in the absence of donor-specific anti-HLA antibodies, repeating HLA class I mismatches with subsequent islet infusions.     

Is complete mesocolic excision with central vascular ligation safe and effective in the surgical treatment of right-sided colon cancers? A prospective study

Purpose

Complete mesocolic excision (CME) with central vascular ligation (CVL) has been proposed for treatment of colon cancers based on the same principles as total mesorectal excision. Impressive outcomes have been reported, however, direct comparisons with the classic procedure are lacking.

Methods

Forty-five consecutive patients operated on in the last 5 years with CME and CVL right hemicolectomy entered the study. Fifty-eight right-sided colon cancer patients operated in the previous 5 years with classic approach constituted the control group. Intra- and postoperative course assessed the safety of the procedure. Primary end-points for oncological adequacy were recurrence and survival rate.

Results

All operations were successful with no increase in postoperative complications (p?=?0.85). Number of harvested nodes and length of vascular ligation were shown to be significantly better in the CME group (p?<?0.01). A higher number of tumor deposits were harvested thus allowing chemotherapy in newly upstaged patients. Locoregional recurrences were never experienced in CME patients (p?=?0.03). The risk of cancer-related death was reduced by over one half in all CME patients, and even by three quarters in node-positive tumors. The classic operation was significantly associated with poor outcome (p?<?0.01).

Conclusion

This study shows that CME with CVL is a safe and effective surgical approach for right colon cancer, thus confirming the previously reported oncological adequacy. The procedure was shown to significantly decrease local recurrences and to improve the survival rate, particularly in node-positive patients. Urgent diffusion of this technique is warranted.