Protein-DNA Interactions at the Opossum Npt2a Promoter are Dependent upon NHERF-1.

BACKGROUND/AIMS: Phosphate homeostasis is controlled by the renal reabsorption of Pi by the type IIa sodium phosphate cotransporter, Npt2a, which is localized in the proximal tubule brush border membrane. Regulation of Npt2a expression is a key control point to maintain phosphate homeostasis with most studies focused on regulating protein levels in the brush border membrane. Molecular mechanisms that control Npt2a mRNA, however, remain to be defined. We have reported that Npt2a mRNA and protein levels correlate directly with the expression of the Na+/H+ exchanger regulatory factor 1 (NHERF-1) using opossum kidney (OK) cells and the NHERF-1-deficient OK-H cells. The goal of this study was to determine whether NHERF-1 contributes to transcriptional and/or post-transcriptional mechanisms controlling Npt2a mRNA levels. METHODS: Npt2a mRNA half-life was compared between OK and NHERF-1 deficient OK-H cell lines. oNpt2a promoter-reporter gene assays and electrophoretic mobility shift assays (EMSA) were used identify a NHERF-1 responsive region within the oNpt2a proximal promoter. RESULTS: Npt2a mRNA half-life is the same in OK and OK-H cells. The NHERF-1 responsive region lies within the proximal promoter in a region that contains a highly conserved CAATT box and G-rich element. Specific protein-DNA complex formation with the CAATT element is altered by the absence of NHERF-1 (OK v OK-H EMSA) although NHERF-1 does not directly contribute to complex formation. CONCLUSION: NHERF-1 helps maintain steady-state Npt2a mRNA levels in OK cells through indirect mechanisms that help promote protein-DNA interactions at the Npt2a proximal promoter.

Outcome of patients on combined extracorporeal membrane oxygenation and continuous renal replacement therapy: a retrospective study.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a lifesaving therapy used in the management of cardiopulmonary failure. Continuous renal replacement therapy (CRRT) is often added to the treatment for the correction of fluid and electrolyte imbalance in patients with acute kidney injury. Most of the literature on the use of combined ECMO and CRRT has been on pediatric patients. There are limited outcome data on the use of these combined modalities in adult patients. METHODS: This is a retrospective analysis of all the patients above the age of 18 years who underwent combined ECMO and CRRT at a tertiary care medical center during the period January 2007 to January 2012. The primary outcomes measured were mortality at one year and renal recovery or dialysis dependence at one month. RESULTS: A total of 40 patients who were treated concurrently with ECMO and CRRT were identified. The mean age was 47.01 ± 18.29 years. The most common indications for initiation of CRRT were combined fluid overload and electrolyte imbalance. Mortality at one month was (32/40) 80%. Among the 8 survivors (20%), 3 patients required continuation of hemodialysis and 5 patients were independent of dialysis at 30 days. CONCLUSIONS: Mortality of patients treated with combined ECMO and CRRT is high. Initiation of CRRT in these patients is simply an indicator of severity of illness and fatality. Younger age, higher arterial pH, left ventricular dysfunction and use of VA ECMO are associated with improved survival in these patients.

Laparoscopic surgery for endometrial cancer: increasing body mass index does not impact postoperative complications.

OBJECTIVE: To determine the effect of body mass index on postoperative complications and the performance of lymph node dissection in women undergoing laparoscopy or laparotomy for endometrial cancer. METHODS: Retrospective chart review of all patients undergoing surgery for endometrial cancer between 8/2004 and 12/2008. Complications graded and analyzed using Common Toxicity Criteria for Adverse Events ver. 4.03 classification. RESULTS: 168 women underwent surgery: laparoscopy n=65, laparotomy n=103. Overall median body mass index 36.2 (range, 18.1 to 72.7) with similar distributions for age, body mass index and performance of lymph node dissection between groups. Following laparoscopy vs. laparotomy the percent rate of overall complications 53.8:73.8 (p=0.01), grade ≥3 complications 9.2:34.0 (p<0.01), ≥3 wound complications 3.1:22.3 (p<0.01) and ≥3 wound infection 3.1:20.4 (p=0.01) were significantly lower after laparoscopy. In a logistic model there was no effect of body mass index (≥36 and<36) on complications after laparoscopy in contrast to laparotomy. Para-aortic lymph node dissection was performed by laparoscopy 19/65 (29%): by laparotomy 34/103 (33%) p=0.61 and pelvic lymph node dissection by laparoscopy 21/65 (32.3%): by laparotomy 46/103 (44.7%) p=0.11. Logistic regression analysis revealed that for patients undergoing laparoscopy for stage I disease there was an inverse relationship between the performance of both para-aortic lymph node dissection and pelvic lymph node dissection and increasing body mass index (p=0.03 and p<0.01 respectively) in contrast to the laparotomy group where there was a trend only (p=0.09 and 0.05). CONCLUSION: For patients undergoing laparoscopy, increasing body mass index did not impact postoperative complications but did influence the decision to perform lymph node dissection.