Cortisol elevations comparable to those that occur during hypoglycemia do not cause hypoglycemia-associated autonomic failure

The concept of hypoglycemia-associated autonomic failure (HAAF) in diabetes posits that recent antecedent iatrogenic hypoglycemia causes both defective glucose counterregulation (by reducing the epinephrine response in the setting of an absent glucagon response) and hypoglycemia unawareness (by reducing the autonomic-sympathetic neural and adrenomedullary response and the resulting neurogenic [autonomic] symptom responses) and thus causes a vicious cycle of recurrent hypoglycemia. To assess the suggestion that it is the cortisol response to antecedent hypoglycemia that mediates HAAF, we tested the hypothesis that plasma cortisol elevations during euglycemia that are comparable to those that occur during hypoglycemia reduce sympathoadrenal and neurogenic symptom responses to subsequent hypoglycemia. To do this, 12 healthy subjects were studied with hyperinsulinemic-stepped hypoglycemic clamps the day after saline or cortisol (1.3 +/- 0.2 micro g. kg(-1) x min(-1)) infusions from 0930 to 1200 and from 1330 to 1600. Compared with saline, antecedent cortisol elevations did not reduce the sympathoadrenal (e.g., final plasma epinephrine levels of 674 +/- 84 vs. 606 +/- 80 pg/ml and final plasma norepinephrine levels of 332 +/- 26 vs. 304 +/- 26 pg/ml) or neurogenic symptom (e.g., final scores of 9.3 +/- 1.1 vs. 13.2 +/- 1.3) responses to subsequent hypoglycemia. Thus, these data do not support the suggestion that cortisol mediates HAAF.     

Effects of image normalization on the statistical analysis of perfusion MRI in elderly brains

Purpose

To fully understand the effects of an image processing methodology on the comparisons of regional patterns of brain perfusion over time and between subject groups.

Materials and Methods

Two brain normalization methods were compared using images of elderly controls and subjects with MCI and AD: the normalization package of statistical parametric mapping (SPM2), and a fully deformable model (FDM). The performance of these two normalization methods was quantitatively evaluated based on two criteria: (a) the alignment accuracy of five brain structures to the colin27 reference volume, and (b) impact of spatial normalization methods on the sensitivity of perfusion magnetic resonance imaging (pMRI).

Results

The delineations of all five brain structures had significantly higher overlap with expert manual tracings using FDM compared to SPM (two‐tailed, P < 0.025). When applied to the biostatistical analysis of CBF maps, a larger number of statistically significant voxels was identified from FDM compared with SPM2 regardless of the effects of the threshold and smoothing kernel.

Conclusion

The greater degree of deformation freedom associated with FDM may yield more accurate region matching and higher statistical sensitivity in identifying regions of CBF differences between elderly groups with prevalent late‐life neurodegenerative conditions. J. Magn. Reson. Imaging 2008;28:1351–1360. © 2008 Wiley‐Liss, Inc.     

Minimally invasive thoracic surgery versus standard surgery

Advances in technology, with the availability of optics and minitelevision cameras and improved endoscopic instrumentation (especially endo-stapler devices), have allowed the surgeon to obtain a superior panoramic view of the thoracic cavity and an optimal surgical manuvrability. This has determined the development, besides the traditional thoracotomic approach, of minimally invasive techniques of video-assisted thoracic surgery (VATS). An auxiliary mini-thoracotomic approach and the magnification of the operating theatre, which allows the surgeon to accomplish difficult manoeuvres under diret view, have progressively extended the indications of this procedure: at first used for the treatment of pneumothorax and pleural effusions, it is now employed in biopsy or atypical resection of pulmonary nodules, lung cancer staging and diagnostic-therapeutical procedures of mediastinal diseases, major pulmonary resections (lobectomy and pneumonectomy) and lung volume reduction surgery for emphysema (LVRS). The Authors review minimally invasive techniques of video-assisted thoracic surgery (VATS), compared to the traditional surgical ones, for the treatment of various thoracic diseases.     

Epidural analgesia with 0.15% ropivacaine plus sufentanil 0.5 microgram ml-1 versus 0.10% bupivacaine plus sufentanil 0.5 microgram ml-1: a double-blind comparison during labour

Background. Ropivacaine has been claimed to produce less motorblock than bupivacaine during epidural analgesia. However, thisadvantage has not been clearly confirmed in obstetric studiesusing low analgesic concentrations in a ratio close to thatsuggested to be equianalgesic. Methods. This double-blind, randomized, prospective study wasperformed in 140 parturients who requested epidural analgesia.After a lumbar epidural catheter had been placed, patients receivedeither 0.10% bupivacaine plus sufentanil 0.5 µg ml^–1or 0.15% ropivacaine plus sufentanil 0.5 µg ml^–1followed by a continuous infusion. Additional boluses were usedfor inadequate levels of analgesia. Visual analogue pain scores,motor block, level of sensory block, supplementary boluses andmain characteristics of labour were recorded. Results. No differences were observed between the two groupsfor pain scores, total volume of anaesthetic solution used [59(23) and 57 (24) ml in the bupivacaine and ropivacaine groupsrespectively], duration of labour, mode of delivery, side-effectsor satisfaction score. The incidence of motor block was notstatistically different between the groups (54 and 69% in thebupivacaine and ropivacaine groups respectively, P=0.07). However,when motor block occurred, survival analysis showed that itoccurred sooner in the course of labour with ropivacaine comparedwith bupivacaine (log rank test, P=0.012). Conclusion. Combined with sufentanil 0.5 µg ml^–1,0.10% bupivacaine and 0.15% ropivacaine produce effective andequivalent analgesia during labour, with similar incidencesof motor block. Br J Anaesth 2002; 88: 809–13     

Cross-Talk Between Sirtuin 1 and High-Mobility Box 1 in Steatotic Liver Graft Preservation

Background

Sirtuin 1 (SIRT1) is a nicotinamide adenine dinucleotide +–dependent histone deacetylase that regulates various pathways involved in ischemia-reperfusion injury (IRI). Moreover, high-mobility group box 1 protein (HMGB1) has also been involved in inflammatory processes during IRI. However, the roles of both SIRT1 and HMGB1 in liver preservation is poorly understood. In this communication, we evaluated the potential relationship between SIRT1 and HMGB1 in steatotic and non-steatotic liver grafts preserved in Institute Georges Lopez solution (IGL-1) preservation solution enriched or not enriched with trimetazidine (TMZ).

Vacuum-assisted closure for complicated neonatal abdominal wounds

Background

Neonatal experience in vacuum-assisted closure (VAC) for complex abdominal wounds remains scant.

Methods

A neonatal VAC protocol was instituted in 2004. The medical records of patients treated with this protocol for the ensuing 3 years were retrospectively reviewed. Continuous data are reported as mean ± SD (range).

Results

Ten VAC applications occurred in 8 neonates for a 3-year period. Gestational age and age at VAC application were 30 ± 6.9 (24-40) weeks and 84.5 ± 51 (21-165) days, respectively. Birth weight and weight at VAC application were 1495 ± 1118 (615-3415) g and 3515 ± 2118 (989-7965) g, respectively. All wound complications occurred after laparotomies (7 elective, 3 emergent). Three wounds included intestinal stomas, and 3 included enterocutaneous fistulae. Average wound area at VAC initiation was 13.6 ± 6.0 (8.5-25) cm². Duration of VAC use was 19.1 ± 15.3 (7-60) days. Vacuum-assisted closure resulted in complete wound closure in all cases and did not result in any local or systemic complications. Five patients (63%) survived to discharge.

Conclusions

Vacuum-assisted closure for complicated abdominal wounds is safe and successful in neonates of any gestational age and birth weight. It provides effective wound management, even in the presence of stomas or enterocutaneous fistulae.     

Incidence of and risk factors for acute stress disorder in children with injuries

BACKGROUND: To assess the incidence of and risk factors for Acute Stress Disorder (ASD) in children with injuries. Numerous studies have documented the increased incidence of PTSD in those initially diagnosed with ASD. PTSD symptoms cause tremendous morbidity and may persist for many years in some children. METHODS: Children hospitalized with one or more injuries were interviewed and assessed with the following: Child Stress Disorders Checklist (CSDC), Family Strains Scale, Brief Symptom Inventory (BSI) and Facial Pain Scale. RESULTS: Participants included sixty-five children (ages 7-18 years). The mechanisms of injury varied (e.g. MVC, penetrating). The mean injury severity score was 8.9 +/- 7. The mean length of hospital stay was 4.6 +/- 4.6 days. Altogether, 18 (27.7%) of participants met DSM IV criteria for ASD during their acute hospital stay. Risk factors such as level of family stress, caregiver stress, child's experience of pain, and child's age were predictive of acute stress symptoms. CONCLUSION: We have identified four risk factors of ASD that have implications for the treatment, and possibly, preventative intervention for PTSD. Further investigation and greater understanding of risk factors for ASD in children with injuries may facilitate the design of acute interventions to prevent the long-term negative outcomes of traumatic events.     

Renal angiomyolipoma: clinicopathologic study of 194 cases with emphasis on the epithelioid histology and tuberous sclerosis association

The majority of renal angiomyolipoma (AML) is sporadic and occasionally it occurs as part of tuberous sclerosis complex (TSC). Epithelioid AML (EAML), an uncommon variant, is considered potentially malignant based on anecdotal case reports. The prognostic significance of epithelioid component in an otherwise typical AML is uncertain. We studied 194 AMLs for the clinicopathologic features of epithelioid and TSC-associated AMLs. Epithelioid component was present in 15 cases (7.7%) with an average amount of 51% (range: 10% to 100%). Histologically, the epithelioid tumor cells were categorized into small, intermediate, and large cell type based on the cell size. Worrisome histologic features were seen in many EAMLs, including coagulative tumor necrosis in 27% (4/15), nuclear atypia in 93% (14/15), mitosis in 47% (7/15), and atypical mitosis in 1 case. All 15 EAML patients had a mean follow-up time of 5.1 years and none had local recurrence or distant metastasis. Sixteen (8.2%) AMLs occurred in patients with definitive TSC. Three histologic features, namely microscopic AML foci, epithelioid component, and epithelial cysts, were present in 10 (62.5%), 4 (25%), and 44% (7/16), respectively, of TSC-associated AMLs, compared with 11 (6.2%), 11 (6.2%), and 6 (3.4%), respectively, in non-TSC-associated AMLs (P value all <0.01). In summary, all 15 cases of EAMLs in our study had benign clinical outcomes despite adverse pathologic features. Epithelioid component, epithelial cysts, and microscopic AML foci are strongly associated with TSC and the presence of all 3 features should raise strong suspicion for TSC.     

Effect of rhBMP‐2 on tibial plateau fractures in a canine model

This study was to determine the efficacy of recombinant human bone morphogenetic protien‐2 (rhBMP‐2)/calcium phosphate matrix (CPX) paste to accelerate healing in a canine articular fracture model with associated subchondral defect. rhBMP‐2/CPX (BMP), CPX alone (CPX) or autogenous bone graft (ABG) was administered to a canine articular tibial plateau osteotomy with a subchondral defect in each of 21 female dogs. The unoperated contralateral limbs served as controls. Ground reaction forces, synovial fluid, radiographic changes, mechanical testing, bone density, and histology of bone and synovium were analyzed at 6 weeks after surgery. Radiographic analysis demonstrated that the BMP and CPX groups showed improved bony healing compared to the ABG group at week 6. Histomorphometric analysis demonstrated that the BMP group had significantly increased trabecular bone volume compared to the CPX and ABG groups. Mechanical testing revealed that the BMP group had significantly greater maximum failure loads than the ABG group. Histological analysis demonstrated that the BMP group had significantly less sub‐synovial inflammation than CPX group. This study demonstrated that rhBMP‐2/CPX accelerated healing of articular fractures with subchondral defect compared to ABG in most of the parameters evaluated, and had less subsynovial inflammation than the CPX alone in a canine model. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 466–471, 2009