Ischemic preconditioning specifically restores complexes I and II activities of the mitochondrial respiratory chain in ischemic skeletal muscle

OBJECTIVE: Defective mitochondrial function has been reported in patients presenting with peripheral arterial disease, suggesting it might be an important underlying mechanism responsible for increased morbidity and mortality. We therefore determined the effects of prolonged ischemia on energetic skeletal muscle and investigated whether ischemic preconditioning might improve impaired electron transport chain and oxidative phosphorylation in ischemic skeletal muscle. METHODS: Thirty rats were divided in three groups: the control group (sham, n = 9) underwent 5 hours of general anesthesia without any ischemia, the ischemia-reperfusion (IR) group (n = 11) underwent 5 hours ischemia induced by a rubber band tourniquet applied on the left root of the hind limb, and in the third group, preconditioning (PC group, n = 10) was performed just before IR and consisted of three cycles of 10 minutes of ischemia, followed by 10 minutes reperfusion. Maximal oxidative capacities (V(max)) of the gastrocnemius muscle and complexes I, II, and IV of the mitochondrial respiratory chain were determined using glutamate-malate (V(max)), succinate (V(s)), and N, N, N,'N'-tetramethyl-p-phenylenediamine dihydrochloride ascorbate as substrates. RESULTS: Physiologic characteristics were similar in the three groups. Ischemia reduced V(max) by 43% (4.5 +/- 0.4 vs 7.9 +/- 0.5 micromol O(2)/(min x g dry weight), P < .01) and V(s) by 55% (2.9 +/- 0.3 vs 6.3 +/- 0.4 micromol O(2)/min/g dry weight; P < .01) in the IR and sham groups, respectively, and impairments of mitochondrial complexes I and II activities were evident. Of interest was that preconditioning prevented ischemia-induced mitochondrial dysfunction. Both V(max) and V(s) were significantly higher in the PC rats than in IR rats (+32% and +41%, respectively; P < .05), and were not different from sham values. CONCLUSIONS: Ischemic preconditioning counteracted ischemia-induced impairments of mitochondrial complexes I and II. These data support that ischemic preconditioning might be an interesting approach to reduce muscular injuries in the setting of ischemic vascular diseases.     

Genomic Profiling of Intrahepatic Cholangiocarcinoma: Refining Prognosis and Identifying Therapeutic Targets

Background

The molecular alterations that drive tumorigenesis in intrahepatic cholangiocarcinoma (ICC) remain poorly defined. We sought to determine the incidence and prognostic significance of mutations associated with ICC among patients undergoing surgical resection.

Methods

Multiplexed mutational profiling was performed using nucleic acids that were extracted from 200 resected ICC tumor specimens from 7 centers. The frequency of mutations was ascertained and the effect on outcome was determined.

Results

The majority of patients (61.5 %) had no genetic mutation identified. Among the 77 patients (38.5 %) with a genetic mutation, only a small number of gene mutations were identified with a frequency of >5 %: IDH1 (15.5 %) and KRAS (8.6 %). Other genetic mutations were identified in very low frequency: BRAF (4.9 %), IDH2 (4.5 %), PIK3CA (4.3 %), NRAS (3.1 %), TP53 (2.5 %), MAP2K1 (1.9 %), CTNNB1 (0.6 %), and PTEN (0.6 %). Among patients with an IDH1-mutant tumor, approximately 7 % were associated with a concurrent PIK3CA gene mutation or a mutation in MAP2K1 (4 %). No concurrent mutations in IDH1 and KRAS were noted. Compared with ICC tumors that had no identified mutation, IDH1-mutant tumors were more often bilateral (odds ratio 2.75), while KRAS-mutant tumors were more likely to be associated with R1 margin (odds ratio 6.51) (both P < 0.05). Although clinicopathological features such as tumor number and nodal status were associated with survival, no specific mutation was associated with prognosis.

Conclusions

Most somatic mutations in resected ICC tissue are found at low frequency, supporting a need for broad-based mutational profiling in these patients. IDH1 and KRAS were the most common mutations noted. Although certain mutations were associated with ICC clinicopathological features, mutational status did not seemingly affect long-term prognosis.     

Urinary low-molecular-weight protein excretion in pediatric idiopathic nephrotic syndrome

Background

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are the most common causes of idiopathic nephrotic syndrome (INS). We have evaluated the reliability of urinary neutrophil-gelatinase-associated lipocalin (uNGAL), urinary alpha1-microglobulin (uα1M) and urinary N-acetyl-beta-D-glucosaminidase (uβNAG) as markers for differentiating MCD from FSGS. We have also evaluated whether these proteins are associated to INS relapses or to glomerular filtration rate (GFR).

Methods

The patient cohort comprised 35 children with MCD and nine with FSGS; 19 healthy age-matched children were included in the study as controls. Of the 35 patients, 28 were in remission (21 MCD, 7 FSGS) and 16 were in relapse (14 MCD, 2 FSGS). The prognostic accuracies of these proteins were assessed by receiver operating characteristic (ROC) curve analyses.

Results

The level of uNGAL, indexed or not to urinary creatinine (uCreat), was significantly different between children with INS and healthy children (p?=?0.02), between healthy children and those with FSGS (p?=?0.007) and between children with MCD and those with FSGS (p?=?0.01). It was not significantly correlated to proteinuria or GFR levels. The ROC curve analysis showed that a cut-off value of 17 ng/mg for the uNGAL/uCreat ratio could be used to distinguish MCD from FSGS with a sensitivity of 0.77 and specificity of 0.78. uβNAG was not significantly different in patients with MCD and those with FSGS (p?=?0.86). Only uα1M, indexed or not to uCreat, was significantly (p?<?0.001) higher for patients in relapse compared to those in remission.

Conclusions

Our results indicate that in our patient cohort uNGAL was a reliable biomarker for differentiating MCD from FSGS independently of proteinuria or GFR levels.     

A difficult airway is not more prevalent in patients suffering from spasmodic torticollis: a case series

PURPOSE: We designed this retrospective study to assess the frequency of difficult airway and difficult intubation in patients with spasmodic torticollis and compare it to that of the general population. METHODS: After Institutional Review Board approval, data were collected from the charts of all the patients with spasmodic torticollis who underwent selective peripheral denervation at our institution between 1988 and 2001. The intubation grade was determined using the Cormack and Lehane laryngoscopic classification. The best laryngeal view was recorded. RESULTS: Data from 342 patients were available for analysis. Fourteen patients had a difficult airway. In two patients, intubation was difficult with three attempts at laryngoscopy in one patient and use of fibreoptic bronchoscopy in the other. Twelve (3.5%) patients presented with laryngoscopic grades of III or IV. The combined prevalence of laryngoscopic view grade III and IV and difficult intubation was 4.4%. CONCLUSIONS: This study assesses the frequency of difficult intubation in patients suffering from spasmodic torticollis. When compared to the general population, these patients do not appear to have a higher frequency of difficult airway or difficult intubation.     

Effects of compression stockings on sympathetic activity and heart rate variability in individuals with spinal cord injury

Objective

To investigate whether wearing graduated compression stockings (GCS) could affect the sympatho-adrenergic and heart rate variability (HRV) responses at rest and after a strenuous wheelchair exercise in individuals with spinal cord injury (SCI).

Design

Crossover trial.

Setting

Department of Physical Medicine and Rehabilitation, Saint Etienne, France.

Participants

Nine men with SCI (five with low paraplegia: LP, four with high paraplegia: HP).

Interventions

Two maximal wheelchair exercise tests: with and without GCS (21 mmHg).

Main outcome measures

HRV measurements: high frequency (HF), low frequency (LF), and LF/HF ratio. Norepinephrine (NOR) and epinephrine (EPI), at rest and post-exercise. Secondary measures were: blood pressure, heart rate, maximal power output, oxygen uptake, stroke volume, cardiac output, at rest, during and after exercise.

Results

When wearing GCS: LFnu_wavelet-post significantly increased and HFnu_wavelet-post significantly decreased (P < 0.05) in SCI subjects, leading to an enhance ratio of LF_wavelet/HF_wavelet and a significantly increased in NOR_rest (P < 0.05).

Conclusions

GCS induces an enhanced sympathetic activity in individuals with paraplegia, regardless of the level of the injury. Enhanced post-exercise sympathetic activity with GCS may help prevent orthostatic hypotension or post-exercise hypotension.     

Cardiovascular disease prevalence in patients with inflammatory arthritis, diabetes mellitus and osteoarthritis: a cross-sectional study in primary care

ABSTRACT: BACKGROUND: There is accumulating evidence for an increased cardiovascular burden in inflammatory arthritis, but the true magnitude of this cardiovascular burden is still debated. We sought to determine the prevalence rate of non-fatal cardiovascular disease (CVD) in inflammatory arthritis, diabetes mellitus and osteoarthritis (non-systemic inflammatory comparator) compared to controls, in primary care. METHODS: Data on CVD morbidity (ICPC codes K75 (myocardial infarction), K89 (transient ischemic attack), and/or K90 (stroke/cerebrovascular accident)) from patients with inflammatory arthritis (n = 1,518), diabetes mellitus (n = 11,959), osteoarthritis (n = 4,040) and controls (n = 158,439) were used from the Netherlands Information Network of General Practice (LINH), a large nationally representative primary care based cohort. Data were analyzed using multi-level logistic regression analyses and corrected for age, gender, hypercholesterolemia and hypertension. RESULTS: CVD prevalence rates were significantly higher in inflammatory arthritis, diabetes mellitus and osteoarthritis compared with controls. These results attenuated - especially in diabetes mellitus - but remained statistically significant after adjustment for age, gender, hypertension and hypercholesterolemia for inflammatory arthritis (OR = 1.5 (1.2-1.9)) and diabetes mellitus (OR = 1.3 (1.2-1.4)). The association between osteoarthritis and CVD reversed after adjustment (OR = 0.8 (0.7-1.0)). CONCLUSIONS: These results confirm an increased prevalence rate of CVD in inflammatory arthritis to levels resembling diabetes mellitus. By contrast, lack of excess CVD in osteoarthritis further suggests that the systemic inflammatory load is critical to the CVD burden in inflammatory arthritis.     

Cardiac paraganglioma: diagnostic and surgical challenges

Primary cardiac paragangliomas are rare extra-adrenal tumors. Though they account for less than 1% of all primary cardiac tumors, they are considerable sources of morbidity and mortality. In this case review, we discuss the challenges associated with the diagnosis and management of cardiac paragangliomas.     

Multiple-level thoracolumbar burst fractures in teenaged patients

The purpose of this study was to examine the characteristics of multiple-level burst fractures in teenaged patients. Five teenaged patients were identified with this injury pattern. The mean age at injury was 17.6 years. All five patients underwent a posterior fusion and an attempted decompression through ligamentotaxis. One of the five went on to have an anterior decompression. Four of the five patients had spinal instrumentation. Neurologic deficit was present in four patients. The proximal fracture was most often responsible for the neurologic deficit when present. The average length of follow-up was 4.5 years. There was no significant neurologic recovery after hospital discharge. Three of the five patients had minimal or no back pain at latest follow-up. The authors conclude that multiple burst fractures should be treated individually based on their clinical and radiographic characteristics.