N-bromoacetamide removes a calcium-dependent component of channel opening from calcium-activated potassium channels in rat skeletal muscle

Calcium-activated potassium channels from cultured rat skeletal muscle were treated with the protein-modifying reagent N-bromoacetamide (NBA) (0.3-1 mM) and studied in excised patches using patch-clamp techniques. After NBA treatment, channels opened only occasionally, and, in contrast to untreated channels, the open probability was no longer sensitive to intracellular surface calcium ions (1 nM to 100 microM). Channel activity did, however, exhibit a voltage dependence similar in direction and magnitude to that shown before NBA treatment (increasing e-fold with 19 mV depolarization). Distributions of open channel lifetimes revealed that NBA treatment virtually abolished openings of long duration, which suggests that this class of openings requires calcium sensitivity. These effects were not reversed by subsequent washing. Quantitatively similar open probability, voltage dependence, and open-interval distributions were observed in untreated channels in calcium-free medium. These results suggest that NBA removed a calcium- dependent component of channel opening, and that normal channels are able to open in the absence of significant intracellular calcium concentrations

Low Vitamin K and Vitamin D Dietary Intake in Patients with Inflammatory Bowel Diseases

The inadequate dietary intake of Vitamin D and Vitamin K is an easily reversible factor favoring IBD-associated bone loss, but data on Vitamin K are lacking. A 28-item quantitative food frequency questionnaire was administered to 193 IBD patients (89 Crohn’s disease and 104 ulcerative colitis), and 199 controls. Patients’ demographics, clinical and laboratory findings were analyzed in relation to recommended daily allowances. VitD intake was inadequate both in the IBD and control patients (8.3 ± 4.5 µg/day in IBD, 53.1% RDA, and 9.7 ± 5.9 µg/day, 63.2% RDA, respectively). Conversely, the mean ViK intake was less than adequate in IBD, at 116.7 ± 116.3 µg/day (78.7% RDA), and high in controls, at 203.1 ± 166.9 µg/day (138.8% RDA). Nonetheless, due to marked interindividual differences, diets were severely lacking VitK in 40% of UC and 49% of CD patients, more so in females and those with active disease. The intake of Vit D was non-significantly lower in colitis than that in Crohn’s disease (7.9 vs. 8.7 µg/day). The opposite was observed for VitK (123.5 vs. 107.0 µg/day). Thus, the diet lacks the micronutrients involved in bone wellbeing in a large proportion of IBD patients. While VitD supplementation is the rule, VitK shortages need proactive nutritional intervention. Keywords: IBD; vitamin K; vitamin D; diet in IB

Methods and advanced Equipment for Simulation and Treatment in Radiation Oncology: programa MAESTRO

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Intramedullary nailing for pertrochanteric fractures of proximal femur: a consecutive series of 323 patients treated with two devices

Introduction: Pertrochanteric fractures (PFs) frequently affect the lower limb of osteoporotic patients and represent an important cause of morbidity and mortality in the elderly. In this prospective randomized controlled trial, we have compared functional and radiological results and complications of patients affected by PFs treated with two intramedullary proximal femoral nails. Materials: We enrolled 323 subjects with PFs, classified according to AO/OTA system as 31.A1 (pertrochanteric simple) and 31.A2 (pertrochanteric multifragmentary). Patients were divided into two groups according to the osteosynthesis devices: group A, Elos-Intrauma® nail (155 cases) and group B, Gamma 3-Stryker® nail (168 cases). Pre-operatively, the baseline characteristics of each patient (gender, age, weight and BMI) were collected. Intraoperative blood loss, subjective pain by visual analogue scale (VAS), esthetic satisfaction, functional scores of the hip by Harris Hip Score (HHS), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were noted. The post-operative degree of fracture reduction was assessed. Each patient had a minimum follow-up of 12 months. Results: The study group was composed of 106 male and 217 female with an average age of 85.4 (range, 65-90, standard deviation (SD) 5.95) years. No statistical differences about sex and age distribution were noted between the two groups. Group A reported lower intraoperative blood loss, 45 ml vs 51 ml, respectively (p < 0.001). There was not any statistical difference about operative time. Group A had a better reduction of fracture (p = 0.0347). The greatest difference was detectable comparing subgroups 31.A2 (p = 0.032). There were no statistical differences about complication frequency and the overall rate was 25% (80 cases). Finally, there was no difference in terms of VAS, HHS, and WOMAC score between the two groups on each follow-up. Patients of group A showed a higher subjective satisfaction index at 1 post-operative year, 7.42 (SD 1.19) vs 6.45 (SD 1.35) of group B (p < 0.001). Conclusion: Elos® nail is a reliable device on a short-term follow-up and represents an alternative choice to the Gamma 3® nail, a well-known and appreciated system for over 25 years

Unusual Skin Toxicity after a Chemotherapic Combination

As known calciphylaxis (CPX) is a rare condition involving subcutaneous vascular calcification and cutaneous necrosis, mostly observed in patients with renal failure. However CPX may also appear in patients affected by polymyositis, Sjogren syndrome, Lupus Erythematosus systemicus, Sarcoidosis and rheumatoid arthritis, especially in children. Clinically CPX can present itself as subcutaneous nodules, infiltrate plaques or purpuric-like and livedo-like plaques, while in the late stages necrotic ulcers (with a bizarre shape and severe pain) may be the main cutaneous manifestations

The RCK2 domain of the human BKCa channel is a calcium sensor

Large conductance voltage and Ca2+-dependent K+ channels (BKCa) are activated by both membrane depolarization and intracellular Ca2+. Recent studies on bacterial channels have proposed that a Ca2+-induced conformational change within specialized regulators of K+ conductance (RCK) domains is responsible for channel gating. Each pore-forming α subunit of the homotetrameric BKCa channel is expected to contain two intracellular RCK domains. The first RCK domain in BKCa channels (RCK1) has been shown to contain residues critical for Ca2+ sensitivity, possibly participating in the formation of a Ca2+-binding site. The location and structure of the second RCK domain in the BKCa channel (RCK2) is still being examined, and the presence of a high-affinity Ca2+-binding site within this region is not yet established. Here, we present a structure-based alignment of the C terminus of BKCa and prokaryotic RCK domains that reveal the location of a second RCK domain in human BKCa channels (hSloRCK2). hSloRCK2 includes a high-affinity Ca2+-binding site (Ca bowl) and contains similar secondary structural elements as the bacterial RCK domains. Using CD spectroscopy, we provide evidence that hSloRCK2 undergoes a Ca2+-induced change in conformation, associated with an α-to-β structural transition. We also show that the Ca bowl is an essential element for the Ca2+-induced rearrangement of hSloRCK2. We speculate that the molecular rearrangements of RCK2 likely underlie the Ca2+-dependent gating mechanism of BKCa channels. A structural model of the heterodimeric complex of hSloRCK1 and hSloRCK2 domains is discussed