Water and total CO2 reabsorption along the rat proximal convoluted tubule

Micropuncture experiments were performed on rat kidney to evaluate the profile of water and total CO₂ reabsorption along the proximal tubule. Three to eight samples were collected along the same nephron and the puncture-to-glomerulus distances were measured for each site. In Munich rats with accessible glomeruli, the water reabsorption rate was found to be constant all along the first five millimeters of proximal tubule. In Sprague Dawley rats with no accessible glomerulus, the same observation was made for these five millimeters, and the water reabsorption rate per mm along this segment was found to be a function of the glomerular filtration rate. For the two last millimeters of tubule accessible at the kidney surface, the water reabsorption rate was found to decrease in 5 out of the 21 tubules studied and ranged from 0.15–3.5 nl·min^–1·mm^–1.In Sprague Dawley rats the fall in the luminal total CO₂ concentration (CO₂)_t along the tubular length was nearly constant (21 mmole·l^–1) between Bowman's capsule and the end proximal tubule, irrespective of the plasma (CO₂)_t value. The distance needed to reach half-maximum total CO₂ reabsorption varied from 1.1–1.9 mm from one tubule to another, as a function of the total CO₂ filtered load. These data suggest that the tubular length involved in avid bicarbonate reabsorption increases as a function of the filtered load and that in the first millimeters of tubule, bicarbonate reabsorption depends on a rapidly saturable mechanism. However, no close relationship was found between total CO₂ movement or the calculated transepithelial chloride gradient on the one hand and water reabsorption along the convoluted proximal tubule on the other.     

Caval perforation with bronchial communication: a rare complication of long-term venous access

Superior vena cava (SVC) perforation with bronchial communication is a very rare complication of long-term venous access. A patient recently presented with erosion of a venous port catheter into a bronchus, with infusion of medications into the bronchus and associated SVC syndrome. A high position of the catheter tip against the wall of the SVC and the beveled style of cut on the catheter tip contributed to this complication. A unique combination of percutaneous techniques was helpful in managing this complication, and surgery was avoided.     

Load-release points of two novel ureteral stone-trapping devices

PURPOSE: We compared the load-release points of the Stone Cone and the new Cook Urological NTrap devices using an in vitro model of the ureter. MATERIALS AND METHODS: A strictured-ureter model was created using urethane tubing with a wire tie around it. A plastic bead was lodged above this narrowing. The Stone Cone, then the NTrap, was deployed in turn above this bead. The force required for each device to undeploy was measured over five trials. RESULTS: Each device released the bead in every trial. The Stone Cone released at a mean of 0.190 lb, while the NTrap yielded at 0.861 lb. CONCLUSIONS: Both of the devices released the plastic bead reliably and at low loads, although the NTrap did require statistically significantly more force than the Stone Cone. However, the loads for both devices were <1 lb, so the devices are unlikely to result in ureteral trauma. Whether a slight increase in load-release force or differences in design result in better stone-clearing ability of one device should be assessed in clinical trials.     

Knowing the diagnosis and counselling the relatives of a person with dementia: the perspective of home nurses and home care workers in Belgium

Home nurses and home care workers share the care for a person with dementia with family caregivers, and are confronted with their needs for medical and service-related information, for advice on how to cope with the behaviour changes, and for emotional support. The first objective of the present study was to describe some of the conditions for effective counselling, such as the perception that knowing the diagnosis has positive consequences for the formal caregivers. A second objective was to describe the formal caregivers' counselling practice, and ascertain its relationship with the psychological variables of attitudes, self-efficacy and subjective norm. A postal questionnaire was sent to 287 home nurses and 1259 home care workers in a defined region of Belgium; the questionnaire was returned by 169 home nurses (58.9% response) and 665 home care workers (52.8% response). The Theory of Planned Behaviour was the organising framework which underpinned the development of the instruments. Only the 168 home nurses and 601 home care workers reporting experience with caregiving to people with dementia were included in the analysis. Formal caregivers indicated that knowing the diagnosis was important, but it could facilitate or hinder caregiving. They were able to describe behavioural characteristics which are indicative of dementia, but only in a limited way, and their strategies to uncover the diagnosis were also limited. Formal caregivers reported that they supported family members emotionally, advised about communication with the person with dementia and informed family caregivers about services. However, providing family caregivers with information about dementia lagged behind these forms of support. In general, nurses scored higher than home care workers. Multiple linear regression analysis was used to investigate the relationships between self-reported practice and the concepts of the model. In both professions, attitudes and self-efficacy were found to be strong independent predictors, and the implications for practice are discussed.     

Noncompliance with Behavioral Recommendations Following Bariatric Surgery

Background: Bariatric surgery has been increasingly utilized for treatment of severe obesity. Although initial weight loss following surgery is almost completely assured, little is known about long-term out-come and patient compliance with post-surgical behavioral recommendations for diet and exercise that would improve outcome. The purpose of this study was to examine the rate of noncompliance with behavioral recommendations and to identify the incidence of psychological concerns following bariatric surgery. Method: Subjects were identified from an active clinical data-base of prospective clinical follow-up of all bariatric surgery patients. 100 consecutive patients who underwent Roux-en-Y gastric bypass were identified, and a chart review was conducted at 6 and 12 months postoperatively to gather demographic data and identify the prevalence of noncompliance identified in monthly follow-up visits. Also, patients were asked about depression, relationship/sexual concerns, and medical complications. Results: 81 women and 19 men were followed for 1 year. The majority of patients reported noncompliance in at least one area, with lack of exercise and snacking being most frequently cited (41%, 37% respectively overall). Most patients were compliant with eating protein first and avoiding sodas. At 12 months follow-up, 12% reported depression, 4% reported sexual concerns and 2% reported relationship problems. Also, 9% reported having experienced some medical complication related to their surgery. Conclusion: Noncompliance with behavioral recommendations is pervasive following bariatric surgery, with lack of exercise being the most likely area of noncompliance. Because of the importance of compliance with behavioral recommendations for the successful outcome of bariatric surgery, further research is warranted to further clarify the factors that impact long-term outcome and to design interventions to improve compliance.     

Impact of colloid response on survival after preoperative radiotherapy in locally advanced rectal carcinoma

Neoadjuvant therapy for rectal carcinoma modifies morphology and natural history of the tumor. Colloid response defined by predominant colloid changes with or without residual tumor cells is a form of tumor response whose impact on survival is unknown. This study evaluated influence of tumor histologic response, especially of colloid response, on survival in patients treated by long-course preoperative radiotherapy for rectal cancer. In 200 patients with uT3-T4 or N1 rectal carcinomas, influence of type of surgery, dose of radiotherapy, residual tumor size, surface tumor aspect, tumor response (downstaging vs. colloid or no response), tumor grade, vascular and neural invasion, circumferential margin, and postoperative chemotherapy on 5-year overall and disease-free survival were studied by univariate and multivariate analyses. A colloid response was observed in 20% of the cases. Tumor response, circumferential margin, and vascular invasion were independently associated with the disease-free survival. Patients with downstaging had a better disease-free survival than patients without response (80% vs. 54%), whereas those with colloid response had an intermediate survival (64%). After colloid response, the rate of recurrence was similar to patients with downstaging for local recurrence (0%-3%) and to those with no response for distant recurrence (28%). After preoperative radiotherapy for rectal cancer, survival and type of recurrence are influenced by the tumor response. The intermediate natural history of patients with colloid response suggests taking colloid response into account in postoperative tumor staging to optimize adjuvant therapy.     

MALT1 and the API2-MALT1 fusion act between CD40 and IKK and confer NF-kappa B-dependent proliferative advantage and resistance against FAS-induced cell death in B cells

The most frequently recurring translocations in mucosa-associated lymphoid tissue (MALT) B-cell non-Hodgkin lymphoma, t(11;18)(q21;q21) and t(14;18)(q32; q21), lead to formation of an API2-MALT1 fusion or IgH-mediated MALT1 overexpression. Various approaches have implicated these proteins in nuclear factor kappaB (NF-kappa B) signaling, but this has not been shown experimentally in human B cells. Immunohistochemistry showed that MALT1 is predominantly expressed in normal and malignant germinal center B cells, corresponding to the differentiation stage of MALT lymphoma. We expressed MALT1 and apoptosis inhibitor-2 API2/MALT1 in human B-cell lymphoma BJAB cells and found both transgenes in membrane lipid rafts along with endogenous MALT1 and 2 binding partners involved in NF-kappa B signaling, B-cell lymphoma 10 (BCL10) and CARMA1 (caspase recruitment domain [CARD]-containing membrane-associated guanylate kinase [MAGUK] 1). API2-MALT1 and exogenous MALT1 increased constitutive NF-kappa B activity and enhanced I kappa B kinase (IKK) activation induced by CD40 stimulation. Both transgenes protected BJAB cells from FAS (CD95)-induced death, consistent with increases in NF-kappa B cytoprotective target gene expression, and increased their proliferation rate. Expression of a dominant-negative I kappa B alpha mutant showed that these survival and proliferative advantages are dependent on elevated constitutive NF-kappa B activity. Our findings support a model in which NF-kappa B signaling, once activated in a CD40-dependent immune response, is maintained and enhanced through deregulation of MALT1 or formation of an API2-MALT1 fusion.