Chronic endothelin antagonism restores cerebrovascular function in diabetes

OBJECTIVE: Diabetes profoundly alters vascular function and is a risk factor for cerebrovascular disease. Diabetes increases myogenic tone and decreases responsiveness to adenosine triphosphatase (ATP)-sensitive K(+) (K(ATP)) channel openers and endothelium-dependent vasodilators. The mechanism(s) by which diabetes impairs cerebrovascular function remain obscure. In the present study, the effects of the potent vasoactive peptide endothelin-1 on myogenic tone and endothelium-dependent and potassium channel-mediated vasodilation in middle cerebral arteries from diabetic and nondiabetic rats were investigated. METHODS: Twenty-eight Wistar rats were divided into four experimental groups (n = 7 per group): control (C), control treated with bosentan (an endothelin A/B receptor antagonist) (CB), diabetic (D), and diabetic bosentan-treated (DB). Diabetes was induced with streptozotocin (D and DB groups), after which chronic bosentan treatment was initiated (CB and DB groups). Middle cerebral arteries were mounted in a pressure myograph, and myogenic responses were recorded. In addition, endothelium-dependent and -independent responses and the effects of the K(ATP) channel opener pinacidil were examined. RESULTS: Cerebral arteries from the diabetic and nondiabetic rats constricted in response to graded pressure increases. Maximum myogenic responses (percent constriction at 60 mm Hg) were significantly greater in the D group (38 +/- 3% versus 25 +/- 3% in C; P < 0.02). The enhanced myogenic tone in the D group was completely prevented by bosentan treatment (DB, 23 +/- 5% versus D; P < 0.003) without an effect on the CB group. In addition, bosentan treatment improved endothelium-dependent vasomotion and improved K(ATP)-mediated vasodilation in the DB group (P < 0.001). CONCLUSION: These data describe, for the first time, the interaction between endothelin-1, myogenic tone, and endothelial function in diabetes. Chronic endothelin antagonism restores cerebrovascular function in this model of diabetes and has global implications for the management of cerebrovascular disease in diabetes.     

Cementless total knee arthroplasty in patients 50 years or younger

Total knee arthroplasty now is being advocated for use in younger patients with posttraumatic and rheumatoid arthritis. Advances in technology, design, and materials potentially have allowed for more predictable results. There has been continued interest in cementless fixation for use in younger patients. Between 1986 and 1998, 75 total knee replacements in 57 patients 50 years or younger were done. All surgeries were done by one surgeon (AAH). There were 35 left knees and 40 right knees. The average age of the patients was 42 years (range, 31-50 years). Followup averaged 111 months. Preoperative range of motion was 5 degrees to 106 degrees and postoperative range of motion was 2 degrees to 113 degrees. Modified Hospital for Special Surgery knee scores improved from an average of 67 points preoperatively to an average of 97 points postoperatively. The majority of the diagnoses were posttraumatic arthritis or osteoarthritis (57%), indicating a young, active group of patients. There were two infections and 12 polyethylene exchanges. There were no revisions for loosening or implant failure. There was a correlation between prior knee surgeries and the need for a manipulation. Radiographically, there were no loose implants. Cementless fixation in the young patient with high physical demands was clinically reliable.     

Tranexamic acid versus fibrin sealant in primary total hip replacement: a comparative study

Background

The effectiveness of intravenous tranexamic acid (TA) in reducing blood loss and transfusion requirements during total hip replacement (THR) is well recognised. The aim of this study was to assess the effectiveness of a fibrin sealant in comparison to intravenous TA and a control group.

Patients and methods

We prospectively studied 273 patients with primary hip osteoarthritis who underwent a THR between February 2012 and September 2013. The first 73 patients acted as the control group. The next 100 consecutive patients received fibrin sealant spray, and the last 100 patients received 1 g TA on induction.

Results

The demographic characteristics, surgical time, surgeon grade, anaesthetic type and pre-operative haemoglobin of the three groups were comparable. Both fibrin sealant and intravenous TA were effective in reducing blood loss during THR (15%, p = 0.04 and 22.5%, p = 0.01, respectively), when compared to the control group. However, neither treatment was found to be superior to the other in preventing blood loss p = 0.39. Tranexamic acid was superior to fibrin sealant in decreasing allogeneic transfusion requirements (0 vs. 10%, p = 0.05). There was no significant difference between the groups with regard to proportion of patients with wound leaking problems.

Conclusion

Both fibrin sealant and intravenous tranexamic acid were effective in reducing blood loss. However, tranexamic acid use reduced post-operative transfusion requirements.

     

Change in prostate cancer presentation coinciding with USPSTF screening recommendations at a community-based urology practice

Objective

The benefits of prostate-specific antigen (PSA)–based prostate cancer screening are controversial. We sought to determine the change in prostate cancer presentation coinciding with the release of the United States Preventative Services Task Force recommendations against screening in a high-volume community-based urology practice.

Radiological lumbar stenosis severity predicts worsening sagittal malalignment on full-body standing stereoradiographs

Background Context

Patients with degenerative lumbar stenosis (DLS) adopt a forward flexed posture in an attempt to decompress neural elements. The relationship between sagittal alignment and severity of lumbar stenosis has not previously been studied.

Tumor diameter accurately predicts perioperative outcomes in T1 renal cancer treated with robot-assisted partial nephrectomy

Purpose

To compare diameter as a continuous variable with categorical R.E.N.A.L. nephrometry score (RNS) in predicting surgical outcomes of robotic partial nephrectomy (RPN).

Methods

We retrospectively reviewed consecutive patients receiving RPN at our institution between July 2007 and June 2014 (n = 286). Three separate multivariate analyses were performed to assess the relationship between RNS components (R = radius, E = endophyticity, N = nearness to collecting system, L = location relative to polar lines), total RNS, and diameter as a continuous variable with operating time, warm ischemia time (WIT), and estimated blood loss (EBL). Each linear regression model’s quality of fit to the data was assessed with coefficients of determination (R ²).

Results

Continuous tumor diameter and total RNS were each significantly correlated to operative time, EBL, and WIT (p < 0.001). Categorical R related to operative time (R = 2 vs. R = 1, p = 0.001; R = 3 vs. R = 1, p = 0.001) and WIT (R = 2 vs. R = 1, p = 0.003; R = 3 vs. R = 1, p = 0.016), but not to EBL. For each of these outcomes, diameter outperformed both R and total RNS, as assessed by R ². Age, body mass index, Charlson Comorbidity Index, and anterior versus posterior location did not correlate with surgical outcomes.

Conclusions

In this series of RPN from a high-volume center, surgical outcomes more closely related to tumor diameter than RNS. While RNS provides surgeons a standardized tool for preoperative planning of renal masses, tumor size may be employed as a more familiar measurement when counseling patients on potential outcomes.