Cell-biologic and functional analyses of five new Aquaporin-2 missense mutations that cause recessive nephrogenic diabetes insipidus

Mutations in the Aquaporin-2 gene, which encodes a renal water channel, have been shown to cause autosomal nephrogenic diabetes insipidus (NDI), a disease in which the kidney is unable to concentrate urine in response to vasopressin. Most AQP2 missense mutants in recessive NDI are retained in the endoplasmic reticulum (ER), but AQP2-T125M and AQP2-G175R were reported to be nonfunctional channels unimpaired in their routing to the plasma membrane. In five families, seven novel AQP2 gene mutations were identified and their cell-biologic basis for causing recessive NDI was analyzed. The patients in four families were homozygous for mutations, encoding AQP2-L28P, AQP2-A47V, AQP2-V71M, or AQP2-P185A. Expression in oocytes revealed that all these mutants, and also AQP2-T125M and AQP2-G175R, conferred a reduced water permeability compared with wt-AQP2, which was due to ER retardation. The patient in the fifth family had a G>A nucleotide substitution in the splice donor site of one allele that results in an out-of-frame protein. The other allele has a nucleotide deletion (c652delC) and a missense mutation (V194I). The routing and function of AQP2-V194I in oocytes was not different from wt-AQP2; it was therefore concluded that c652delC, which leads to an out-of-frame protein, is the NDI-causing mutation of the second allele. This study indicates that misfolding and ER retention is the main, and possibly only, cell-biologic basis for recessive NDI caused by missense AQP2 proteins. In addition, the reduced single channel water permeability of AQP2-A47V (40%) and AQP2-T125M (25%) might become of therapeutic value when chemical chaperones can be found that restore their routing to the plasma membrane.     

Real-time in vivo dosimetry using micro-MOSFET detectors during intraoperative electron beam radiation therapy in early-stage breast cancer.

PURPOSE: In a previous paper we reported the results of off-line in vivo measurements using radiochromic films in IOERT. In the present study, a further step was made, aiming at the improvement of the effectiveness of in vivo dosimetry, based on a real-time check of the dose. MATERIALS AND METHODS: Entrance dose was determined using micro-MOSFET detectors placed inside a thin, sterile, transparent catheter. The epoxy side of the detector was faced towards the beam to minimize the anisotropy. Each detector was plugged into a bias supply (standard sensitivity) and calibrated at 5 Gy using 6 MeV electrons produced by a conventional linac. Detectors were characterized in terms of linearity, precision and dose per pulse dependence. No energy and temperature dependence was found. The sensitivity change of detectors was about 1% per 20 Gy accumulated dose. Correction factors to convert surface to entrance dose were determined for each combination of energy and applicator. From November 2004 to May 2005, in vivo dosimetry was performed on 45 patients affected by early-stage breast cancer, who underwent IOERT to the tumour bed. IOERT was delivered using electrons (4-10 MeV) at high dose per pulse, produced by either a Novac7 or a Liac mobile linac. RESULTS: The mean ratio between measured and expected dose was 1.006+/-0.035 (1 SD), in the range 0.92-1.1. The procedure uncertainty was 3.6%. Micro-MOSFETs appeared suitable for in vivo dosimetry in IOERT, although some unfavourable aspects, like the limited lifetime and the anisotropy with no build-up, were found. Prospectively, a real-time action level (+/-6%) on dose discrepancy was defined. CONCLUSIONS: Excellent agreement between measured and expected doses was found. Real-time in vivo dosimetry appeared feasible, reliable and more effective than the method previously published.     

Second Biopsy of Axillary Sentinel Lymph Node for Reappearing Breast Cancer After Previous Sentinel Lymph Node Biopsy

Background Sentinel lymph node biopsy (SLNB) is a safe and accurate axillary staging procedure for patients with primary operable breast cancer. An increasing proportion of these patients undergo breast-conserving surgery, and 5% to 15% will develop local relapses that necessitate reoperation. Although a previous SLNB is often considered a contraindication for a subsequent SLNB, few data support this concern. Methods Between January 2000 and June 2004, 79 patients who were previously treated at our institution with breast-conserving surgery and who had a negative SLNB for early breast cancer developed, during follow-up, local recurrence that was amenable to reoperation. Eighteen of these patients were offered a second SLNB because of a clinically negative axillary status an average of 26.1 months after the primary event. Results In all 18 patients (7 with ductal carcinoma-in-situ and 11 with invasive recurrences), preoperative lymphoscintigraphy showed an axillary sentinel lymph node, with a preoperative identification rate of 100%, and 1 or more SLNs (an average of 1.3 per patient) were surgically removed. Sentinel lymph node metastases were detected in two patients with invasive recurrence, and a complete axillary dissection followed. At a median follow up of 12.7 months, no axillary recurrences have occurred in patients who did not undergo axillary dissection. Conclusions Second SLNB after previous SLNB is technically feasible and likely effective in selected breast cancer patients. A larger population and longer follow-up are necessary to confirm these preliminary data.     

Tramadol. Focus on musculoskeletal and neuropathic pain

In the light of the most recent acquisitions published in the international literature, this review analyzes the pharmacologic features and modes of use of tramadol, one of the most widely used, on a worldwide scale, analgesic agents in acute and chronic pain of moderate to severe intensity. The action of the 2 enantiomers of tramadol--which exert different pharmacologic effects--and of metabolite M1, is differentiated. The global activity of tramadol results from the sum of their specific actions. Data of kinetics show a very high oral bioavailability and the sustained-release (SR) formulations assure a 24-h coverage through the constant blood levels. Data reported in the relevant literature show that tramadol is effective in the treatment of arthrosic and neuropathic pain, with a value of Number Needed to Treat (NNT) of 3.4, and in the mixed nociceptive-neuropathic pain, especially in persistent or chronic pain. Moreover, tramadol maintains a good tolerability profile in the elderly subjects and a good analgesic efficacy in the long-term treatments with reduced pharmacological interactions and a low incidence of constipation. These global features assured its inclusion into the most recent guidelines on the management of chronic pain. Furthermore, data from literature showed that tramadol is devoid of immunosuppressive activity, has a poor tendency to tolerance and a minimum risk of addiction and abuse.     

Laparoscopic Gastric Bypass with Silicone Band in a Pig Model: Prevention of Anastomotic Dilatation – Feasibility Study

Background: Morbid obesity has become a major global health problem. Surgery remains the only effective treatment for patients with severe obesity, because diet reduction methods and pharmacologic agents have not resulted in long-term weight reduction. Gastric bypass (GBP) can provide adequate weight loss, but after some years, dilatation of the gastric pouch and outlet may lead to weight regain by allowing the patient to increase food intake. Methods: 2 groups of 6 pigs underwent laparoscopic GBP. In the first group, a non-adjustable silicone band (Proring?-band, IOC, Innovative Obesity Care, Saint Etienne, France) was positioned 1 cm proximal to the gastrojejunal anastomosis. In the second group, the device used to stabilize the gastric pouch was an adjustable silicone band (Mid-band?, Medical Innovation Developpement, Villeurbanne, France). Weight loss, complications and histological reaction were evaluated after 3 months. Results: Mortality rate was 25% (cardiac arrythmia in 2 pigs). Conversion rate was 25%. The positioning of the band was more difficult with the Mid-band? because of its larger size and the presence of the catheter. The average weight change in the Proring? group was 15.8 kg (3.5–25.1 kg), and in the Mid-band? group was 12.0 kg (6.2–15.1 kg). Morbidity consisted of one intragastric migration of the Proring? band into the gastrojejunal anastomosis, and one infection of the port in the Mid-band? group treated by removal of the port and antibiotics. Conclusion: Use of silicone devices may be safe and effective in the prevention of pouch or outlet dilatation after GBP.