A chronic-constriction injury of the sciatic nerve reduces bilaterally the responsiveness to formalin in rats: a behavioral and hormonal evaluation

Application of four loose ligatures to the sciatic nerve of a rat (chronic constriction injury [CCI]) induces clear hypersensitivity to non-noxious stimulation and chemical irritants. However, in this study, an injection of formalin in the hind paw of a rat with CCI-induced mononeuropathy resulted in an ipsilateral decreased flinching and licking or biting behavior in both phases of the formalin testing. The effect was independent of the formalin concentration used. This altered behavior was accompanied with smaller plasma levels of adrenocorticotrope hormone and corticosterone compared with sham and non-operated animals. Formalin injection in the contralateral nonligated hind paw of CCI rats also reduced the licking or biting behavior as compared with sham-operated and non-operated control animals only in the second phase of the formalin test. Thus, CCI reduces the pain reactivity and hypothalamic-pituitary-adrenal-axis activation to ipsilateral and contralateral formalin injection. Further research should investigate whether the decreased pain reactivity by CCI is situated at the peripheral, spinal, or supraspinal level or is result of changes in the stress reactivity and coping strategies. IMPLICATIONS: We evaluated the changes in the behavioral reactions and the hormonal effects of a noxious chemical stimulus, i.e., formalin injection in animals with previously induced chronic constriction injury to the sciatic nerve. The effect in animals injected at the ipsilateral and contralateral site, sham-operated and controls, were compared.     

Salvage of hyperacute renal transplant hypoperfusion with stent placement: a case report

The authors report on a patient who underwent renal artery stent placement 6 hours after transplantation due to acute hypoperfusion of the transplant, which was diagnosed with intraoperative Doppler ultrasonography. Extensive atherosclerotic disease of the cadaveric transplant renal artery necessitated endarterectomy before creation of the anastomosis, and no further surgical options were considered feasible by the transplant surgeon. Six hours after the transplantation, percutaneous transluminal renal angioplasty and stent placement were performed, resulting in restoration of normal arterial flow and rescue of allograft function.     

Renal function and outcome of PTRA and stenting for atherosclerotic renal artery stenosis

BACKGROUND: Prior studies of percutaneous transluminal renal artery angioplasty and stenting (PTRAS) for atherosclerotic renal artery stenosis (RAS) have shown that renal function is improved in about 25%, stabilizes in about 40%, but worsens in about 25% of patients. The factors predicting benefit remain controversial. We tested the hypothesis that the baseline glomerular filtration rate (GFR) predicts the changes in GFR and blood pressure (BP) after PTRAS. METHODS: Treated hypertensive patients with positive renal color-coded duplex Doppler velocimetry and clinical criteria were screened by arteriography. Patients (N = 105) were included if they had an RAS >or=70%, a transluminal pressure gradient >or=30 mm Hg and, they had more than 100 days of follow-up. GFR was calculated from the serum creatinine concentration (SCr). Patients were divided by baseline GFR into subgroups with normal to mildly impaired (N = 52) or moderately to severely impaired (N = 53) initial GFR, according to a GFR >or=50 or <50 mL. min-1 respectively. All received PTRAS. RESULTS: For the entire group, after a mean follow-up period of 371 days, there were significant reductions in systolic and diastolic BP (before, 160 +/- 26/91 +/- 12 vs. after, 145 +/- 20/83 +/- 10 mm Hg, respectively; mean +/- SD; P < 0.0001), and a modest increase in the calculated GFR (before, 54 +/- 26 vs. after, 62 +/- 28 mL. min-1; mean +/- SD; P < 0.007). However, in the subgroup of patients with an initially lower GFR there was a significant increase in the calculated GFR (from 33.3 +/- 10 to 54 +/- 24 mL. min-1; mean +/- SD; P < 0.0001) despite no significant change in BP (161 +/- 27/90 +/- 12 vs. 151 +/- 21/86 +/- 12; P = NS). In contrast, in the subgroup with an initially higher GFR, there were significant (P < 0.0001) reductions in systolic BP (from 159 +/- 25 to 138 +/- 16 mm Hg) and diastolic BP (from 91 +/- 11 to 81 +/- 9 mm Hg), but no significant change in the calculated GFR (from 75 +/- 21 to 70.2 +/- 30 mL. min-1; P = NS). The significance of GFR variation in subgroups remained after correction of baseline data to exclude the influence of the expected regression to the mean. CONCLUSIONS: Patients with atherosclerotic RAS fulfilling strict criteria of severity may have significant improvements in BP one year after PTRAS but only modest in GFR. The initial GFR may anticipate whether the benefits in the outcome will be in renal function enhancement (those with an initially depressed GFR) or in hypertension control (those with an initially normal or mildly impaired GFR).     

Fibroblast subpopulations in intra-oral wound healing

The objective of this study was to characterize fibroblasts at sequential time points during intra-oral wound healing in the rat. Experimental wounds were made at several time points in the mucoperiosteum of the palate of 35-day-old Wistar rats. Fibroblasts were cultured from the biopsies under standard conditions for the same number of passages. The expression of the integrin subunits alpha 1, alpha 6, and beta 1; and the intermediate filaments alpha-smooth muscle actin and vimentin were analyzed by flow cytometry. Western blot analysis was performed at 0, 8, and 60 days postwounding to confirm the expression of both intermediate filaments. The phenotypic profiles of fibroblasts cultured from subsequent stages in the wound healing process differed considerably. We conclude that distinct fibroblast phenotypes can be isolated from different stages in wound healing. These phenotypes remained stable during in vitro culturing. In addition, cryosections of the wound areas were made at identical time points and were immunohistochemically stained for the same antigens. The immunohistochemical staining correlated well to the flow-cytometric data. These results suggest the occurrence of multiple subpopulations of fibroblasts with a specialized function during wound healing. We hypothesize that undesirable consequences of wound healing might be prevented through the modulation of specific fibroblast subpopulations.     

Ultrasound examination and localization of the sciatic nerve: a volunteer study

BACKGROUND: Few studies have examined the use of ultrasound for sciatic nerve localization. The authors evaluated the usefulness of low-frequency ultrasound in identifying the sciatic nerve at three locations in the lower extremity and in guiding needle advancement to target before nerve stimulation. METHODS: In this prospective observational study, 15 volunteers underwent sciatic nerve examination using a curved ultrasound probe in the range of 2-5 MHz and a Philips-ATL 5000 unit (ATL Ultrasound, Bothell, WA) in the gluteal, infragluteal, and proximal thigh regions. Thereafter, an insulated block needle was advanced inline with the ultrasound beam to reach the nerve target, which was further confirmed by electrical stimulation. The quality of sciatic nerve images, ease of needle to nerve contact, threshold stimulating current, and resultant motor response were recorded. RESULTS: The sciatic nerve was successfully identified in the transverse view as a solitary predominantly hyperechoic structure on ultrasound in all of the three regions examined. The target nerve was visualized easily in 87% and localized within two needle attempts in all patients. Nerve stimulation was successful in 100% after two attempts with a threshold current of 0.42 +/- 0.12 (mean +/- SD) eliciting foot plantarflexion or dorsiflexion. CONCLUSIONS: These preliminary data show that a curved 2- to 5-MHz ultrasound probe provides good quality sciatic nerve imaging in the gluteal, infragluteal, and proximal thigh locations. Ultrasound-assisted sciatic nerve localization is potentially valuable for clinical sciatic nerve blocks.     

Responsiveness and minimum important change of the Oswestry Disability Index in Italian subjects with symptomatic lumbar spondylolisthesis

Background

This study aims to investigate the responsiveness and the minimum important change of the Italian version of the Oswestry Disability Index (ODI-I) in subjects with symptomatic specific low back pain associated with lumbar spondylolisthesis (SPL).

Materials and methods

One hundred and fifty-one patients with symptomatic SPL completed the ODI-I, a 0–100 numerical rating scale (NRS), and performed the prone and supine bridge tests. The global perception of effectiveness was measured with a 7-point Likert scale. Responsiveness was assessed by distribution methods (minimum detectable change [MDC], effect size [ES], standardized response mean [SRM]) and anchor-based methods (ROC curves).

Results

The MDC was 4.23, the ES was 0.95 and the SRM was 1.25. ROC analysis revealed an area under the curve of 0.76 indicating moderate discriminating capacity. The best cut-off point for the dichotomous outcome was 7.5 (sensitivity 90.3%, specificity 56.7%). .

Conclusions

The ODI-I proved to be responsive in detecting changes after conservative treatment in subjects with lumbar SPL.

Level of evidence

II.

     

Pediatric Splenic Injury: Nonoperative Management First!

Abstract Background and Purpose:  In the past splenectomy was the standard procedure for traumatic blunt splenic injury, when bleeding of the spleen occurred. Since the spleen performs important immunological functions the advantage of a spleen-saving approach is preservation of immunological functions. Especially in the pediatric population splenic preservation is an important objective. Spleen-saving treatment, in particular selective nonoperative management, has gained ground in the past 20 years. An 18-year retrospective review was performed to evaluate our cumulative experience with nonoperative management. Endpoints: hemodynamical instability and splenectomy. Methods:  Forty-six patients were identified. Demographics, methods of management, mechanism of injury, injury grade, associated injuries, hemodynamical parameters, bloodtransfusion, complications, ICU and hospital stay were documented and analyzed to determine statistical significance between modes of management. Results:  Initially, 34 patients were managed nonoperatively, while 12 patients underwent laparotomy – with 7 (58.3% of the operative group) of these having splenectomy performed. Three patients (out of 34) failed nonoperative management and required delayed splenorraphy or splenectomy, a 91.2% (3 out of 34 failed) success rate for intended nonoperative management versus 85.7% for intended splenorraphy (1 out of 7 failed). Thus, overall rates of 67.4% nonoperative management and 82.6% splenic conservation were achieved. Analysis of parameters between treatments showed significant differences between nonoperative management and splenorraphy for splenic injury grade II and IV. Conclusion:  We recommend based on our data on children with splenic injury grades II and IV that the standard treatment for children aged 0 to 18 years due to blunt abdominal trauma should be nonoperative management. However management of blunt splenic injury remains a clinical decision, for this reason does not preclude on CT-scan grade V for nonoperative management.