Meromictic Antarctic lakes as recorders of climate change: the structures of Ace and Organic Lakes, Vestfold Hills, Antarctica

The meromictic lakes that occur in closed, rocky basins of the Vestfold Hills provide records of local climate change. From a consideration of the physical structure of these stratified lakes it is apparent that maximum winter under-ice water salinity (associated with minimum water temperatures) is a function of the water level for a particular lake. The structure of the lakes will also be affected by changes in water balance. An increase in water level will result in a lens of fresher water and warmer winter temperatures at the surface of the lake, whereas a decrease will result in increased salinity, colder temperatures and deeper epilimnetic mixing. Evidence of periods oflow water level is retained by the lakes as intervals of near isopycnal water within the water column, which can be used to calculate minimum palaeolevels. Changes in the structures of Organic Lake and Ace Lake between 1975 and 1995 are used in this article to illustrate these points

Control of Biological Exposure to UV Radiation in the Arctic Ocean: Comparison of the Roles of Ozone and Riverine Dissolved Organic Matter

Reports of severe stratospheric ozone depletion over the Arctic have heightened concern about the potential impact of rising ultraviolet-B (UV-B) radiation on north polar aquatic ecosystems. Our optical measurements and modelling results indicate that the ozone-related UV-B influence on food web processes in the Arctic Ocean is likely to be small relative to the effects caused by variation in the concentrations of natural UV-absorbing compounds, known as chromophoric dissolved organic matter(CDOM), that enter the Arctic basin via its large river inflows. The aim of our present study was to develop and apply a simple bio-optical index that takes into account the combined effects of attenuation by atmospheric ozone and water column CDOM, and photobiological weighting for high-latitude environments such as the Arctic Ocean. To this end, we computed values for a biologically effective UV dose rate parameter ('weighted transparency' or T*) based on underwater UV measurements in highlatitude lakes and rivers that discharge into the Arctic Ocean; measured incident UV radiation at Barrow, Alaska; and published biological weighting curves for UV-induced DNA damage and UV photoinhibition of photosynthesis. The results underscore how strongly the Arctic Ocean is influenced by riverine inputs: shifts in CDOM loading (e.g., through climate change, land-use practices, or changes in ocean circulation) can cause variations in biological UV exposure of much greater magnitude than ozone related effects

Wilms' Tumor with Long-delayed Recurrence: 25 Years after Initial Treatment

Wilms' tumor is one of the most frequent malignant neoplasms in childhood. Advances in treatment modalities such as the combination of chemoradiation therapy with surgery have enhanced overall survival. However, recurrence of Wilms' tumor is still a problem. In this case, a 28-year-old female had experienced intermittent abdominal pain, and the computed tomography scan showed a huge pelvic mass. The patient had a history of radical nephrectomy for Wilms' tumor with concurrent chemotherapy at the age of three. The pelvic mass was resected in February 2010 and was confirmed to be a recurrent Wilms' tumor. The recurrent tumor showed a classic triphasic Wilms' tumor growth pattern with frequent mitoses and tumor necrosis. Our case is an extraordinary case of a long-delayed recurrent Wilms' tumor after 25 years, which is the longest disease-free interval ever reported. The possible effects of chemotherapy as well as some other mechanisms of this late relapse are discussed

Comparisons between Macroadenomas and Microadenomas in Cushing's Disease: Characteristics of Hormone Secretion and Clinical Outcomes

It has been suggested that the patients with Cushing's disease secondary to pituitary macroadenomas (>10 mm) have higher basal adrenocorticotropic hormone (ACTH) levels, which are less suppressible on high-dose dexamethasone suppression tests (HDDST). We compared the clinical and biochemical characteristics of patients with macroadenomas (N=7) and microadenomas (N=23) who were diagnosed at Samsung Medical Center in Korea between 1996 and 2006. Basal morning plasma ACTH levels were 101.5±23.2 pg/mL for macroadenoma patients and 83.6±11.1 pg/mL for microadenoma patients (mean±SEMs) (p=0.44). Morning serum cortisol levels were 26.8±3.2 µg/dL for macroadenoma patients and 29.5±2.9 µg/dL for microadenoma patients (p=0.77). The proportion of patients who showed suppressibility on HDDST was almost identical in the two groups (71.4% [5/7] for macroadenoma patients vs. 72.7% [16/22] for microadenoma patients, p=1.00). Furthermore, the remission rate with trans-sphenoidal surgery was similar between the two groups (100% [5/5] for macroadenoma patients vs. 73.3% [11/15] for microadenoma patients, p=0.53). Thus, tumor size is not a major determinant of hormone secretion or clinical outcomes in patients with Cushing's disease

Respiratory Muscle Strength and Cough Capacity in Patients with Duchenne Muscular Dystrophy

The function of inspiratory muscles is crucial for effective cough as well as expiratory muscles in patients with Duchenne muscular dystrophy (DMD). However, there is no report on the correlation between cough and inspiratory muscle strength. To investigate the relationships of voluntary cough capacity, assisted cough techniques, and inspiratory muscle strength as well as expiratory muscle strength in patients with DMD (n = 32). The vital capacity (VC), maximum insufflation capacity (MIC), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured. Unassisted peak cough flow (UPCF) and three different techniques of assisted PCF were evaluated. The mean value of MICs (1918 ± 586 mL) was higher than that of VCs (1474 ± 632 mL) (p < 0.001). All three assisted cough methods showed significantly higher value than unassisted method (212 ± 52 L/min) (F = 66.13, p < 0.001). Combined assisted cough technique (both manual and volume assisted PCF; 286 ± 41 L/min) significantly exceeded manual assisted PCF (MPCF; 246 ± 49 L/min) and volume assisted PCF (VPCF; 252 ± 45 L/min) (F = 66.13, p < 0.001). MIP (34 ± 13 cmH2O) correlated significantly with both UPCF and all three assisted PCFs as well as MEP (27 ± 10 cmH2O) (p < 0.001). Both MEP and MIP, which are the markers of respiratory muscle weakness, should be taken into account in the study of cough effectiveness

Unrelated Hematopoietic Stem Cell Transplantation for Children with Acute Leukemia: Experience at a Single Institution

We evaluate the outcomes in children with acute leukemia who received allogeneic hematopoietic stem cell transplantation (HCT) using unrelated donor. Fifty-six children in complete remission (CR) received HCT from unrelated donors between 2000 and 2007. Thirty-five had acute myeloid leukemia, and 21 had acute lymphoid leukemia. Stem cell sources included bone marrow in 38, peripheral blood in 4, and cord blood (CB) in 14. Four patients died before engraftment and 52 engrafted. Twenty patients developed grade II-IV acute graft-versus-host disease (GVHD) and 8 developed extensive chronic GVHD. With median follow-up of 39.1 months, event free survival and overall survival were 60.4% and 67.5%, respectively, at 5 yr. Events included relapse in 10 and treatment-related mortality (TRM) in 10. The causes of TRM included sepsis in 4, GVHD in 4 (1 acute GVHD and 3 chronic GVHD), veno-occlusive disease in 1 and fulminant hepatitis in 1. Patients transplanted with CB had event free survival of 57.1%, comparable to 63.2% for those transplanted with other than CB. In conclusion, HCT with unrelated donors is effective treatment modality for children with acute leukemia. In children with acute leukemia candidate for HCT but lack suitable sibling donor, unrelated HCT may be a possible treatment option at the adequate time of their disease