Immunohistochemistry for hMLH1 and hMSH2: a practical test for DNA mismatch repair-deficient tumors.

Inactivation of deoxyribonucleic acid (DNA) mismatch repair genes, most commonly human mutL homologue 1 (hMLH1) or human mutS homologue 2 (hMSH2), is a recently described alternate pathway in cancer development and progression. The resulting genetic instability is characterized by widespread somatic mutations in tumor DNA, and is termed high-frequency microsatellite instability (MSI-H). Although described in a variety of tumors, mismatch repair deficiency has been studied predominantly in colorectal carcinoma. Most MSI-H colorectal carcinomas are sporadic, but some occur in patients with hereditary nonpolyposis colorectal cancer (HNPCC), and are associated with germline mutations in mismatch repair genes. Until now, the identification of MSI-H cancers has required molecular testing. To evaluate the role of immunohistochemistry as a new screening tool for mismatch repair-deficient neoplasms, the authors studied the expression of hMLH1 and hMSH2, using commercially available monoclonal antibodies, in 72 formalin-fixed, paraffin-embedded tumors that had been tested previously for microsatellite instability. They compared immunohistochemical patterns of 38 MSI-H neoplasms, including 16 cases from HNPCC patients with known germline mutations in hMLH1 or hMSH2, with 34 neoplasms that did not show microsatellite instability. Thirty-seven of 38 MSI-H neoplasms were predicted to have a mismatch repair gene defect, as demonstrated by the absence of hMLH1 and/or hMSH2 expression. This included correspondence with all 16 cases with germline mutations. All 34 microsatellite-stable cancers had intact staining with both antibodies. These findings clearly demonstrate that immunohistochemistry can discriminate accurately between MSI-H and microsatellite-stable tumors, providing a practical new technique with important clinical and research applications.     

Effect of muscle strength and movement speed on the biomechanics of rising from a chair in healthy elderly and young women

The ability to rise from a chair is an important task of daily living that is difficult for many elderly individuals to perform, and is particularly challenging when performed quickly. It is important to understand what factors limit performance of the task in older people, so that effective remedial approaches can be developed. In this study, we quantified lower-extremity muscle strength and chair-rise biomechanics in 12 young and 26 healthy elderly women during chair rise at normal and fast speeds without use of the hands. We found that hip and knee extensor torques, vertical and horizontal momentum, and vertical and horizontal ground reaction forces increased in the same way with speed for all subjects. All subjects increased their speed from normal to fast trials, but the young subjects were able to rise more quickly in the fast trials. In the normal speed trials, elderly subjects generated more trunk flexion and horizontal momentum while still in contact with the chair. Muscle activity patterns were similar for all subjects except that the elderly activated the ankle extensors earlier than the young. Although the elderly subjects were much weaker relative to body weight than the young subjects (48.5±14.1%), they were able to generate sufficient torques to perform the task. However, age-related differences suggest that chair-rise biomechanics were affected by the reduction in muscle strength, and that strength training regimens, particularly for the hip musculature, may be important to maintain chair-rise ability in the elderly.     

Influence of demographics and inhalation injury on burn mortality in children

BACKGROUND: Pulmonary failure has emerged as one of the leading causes of mortality in burned children due, in part, to the success in reducing the incidence of sepsis, early surgery and fluid resuscitation, and new advances in nutritional support. To evaluate the effect of pulmonary injury, age, gender, race, and burn size on mortality, the records of 3179 burned children admitted to our burn center from 1985 to 2001 were reviewed. In this population, 1246 were admitted within 14 days of injury with burns greater than 20% of their total body surface area (TBSA). METHODS: Lethal burn areas (LAs) for a thermal injury only or burn plus inhalation injury were estimated from best fit probit curve within 95% confidence limits. Data analysis was by chi(2)-test, t-test, or Fisher's exact test where appropriate. RESULTS: The lethal burn area for a 10% mortality rate with and without concomitant inhalation injury was a 50 and 73% TBSA burn, respectively. Children up to the age of 3 with >/=20% TBSA burns had a higher rate of mortality (9.9%) compared to those 3-12 years of age (4.9%) and 13-18 years of age (4.2%). Children with 21-80% TBSA burns showed a significant difference in mortality (P<0.05) between those with burn plus inhalation injury (13.9%) and burn only (2.9%), while those with 81-100% TBSA burns showed no significant difference between burn only and burn plus inhalation injury. CONCLUSION: Inhalation injury remains one of the primary contributors to burn mortality. Children under the age of 3 years, however, are at a higher risk both with and without inhalation injury.     

High incidence of myocardial ischemia during postpartum hemorrhage

BACKGROUND: Postpartum hemorrhage remains a major cause of global maternal morbidity and mortality, even in developed countries, despite the use of intensive care units. This study sought to (1) assess whether myocardial ischemia could be associated with and even aggravate hemorrhagic shock in young parturients admitted for postpartum hemorrhage, and (2) identify the independent risk factors for myocardial ischemia. METHODS: On their referral to the intensive care unit, a multidisciplinary team managed parturients with severe postpartum hemorrhage. Ventilation, transfusion, catecholamines, surgery, or angiography with uterine embolization were provided as clinically indicated. Plasma cardiac troponin I levels were used as a surrogate marker of acute myocardial injury and electrocardiograms of myocardial ischemia. RESULTS: A total of 55 parturients were referred with severe postpartum hemorrhage, all in hemorrhagic shock. Twenty-eight parturients (51%) had elevated serum levels of cardiac troponin I (9.4 microg/l [3.7-26.6 microg/l]), which were associated with electrocardiographic signs of ischemia and deteriorated myocardial contractility and correlated with the severity of hemorrhagic shock. Indeed, multivariate analysis identified low systolic and diastolic arterial blood pressure (< 88 and < 50 mmHg, respectively) and increased heart rate (> 115 beats/min) as independent predictors of myocardial injury. In addition, all patients who were given catecholamines also had elevated cardiac troponin I levels. CONCLUSIONS: These results suggest that treatment of postpartum hemorrhage-induced hemorrhagic shock should be coupled with concomitant prevention of myocardial ischemia, even in young parturients.     

A multicentre trial comparing different concentrations of ropivacaine plus sufentanil with bupivacaine plus sufentanil for patient-controlled epidural analgesia in labour

BACKGROUND AND OBJECTIVE: To determine the optimal concentration of ropivacaine for bolus-only patient-controlled epidural labour analgesia, three different doses of ropivacaine were evaluated in comparison with bupivacaine in a double-blinded multicentre study. METHODS: Four hundred-and-fifty labouring parturients at term in three different academic institutions were randomized to four groups receiving bupivacaine 0.125% with sufentanil 0.75 microg mL(-1), ropivacaine 0.125% or 0.175% with sufentanil 0.75 microg mL(-1), or ropivacaine 0.2%. After an initial bolus of 10 mL of the study solution, and once visual analogue scores (VAS) were below 30 mm, patient-controlled epidural analgesia was initiated with a bolus of 4 mL, a lockout interval of 15 min and without a background infusion. Variables studied were the quality of analgesia, incidence of side-effects, the degree of motor blockade, and the mode of delivery. RESULTS: Bupivacaine 0.125% and ropivacaine 0.125% with sufentanil proved equally effective in providing labour analgesia without a difference in local anaesthetic consumption (48.6 +/- 23 mg bupivacaine vs. 52.1 +/- 38 mg ropivacaine), motor blockade or mode of delivery. Ropivacaine 0.175% plus sufentanil enhanced the quality of analgesia of the initial loading dose, whereas ropivacaine 0.2% without sufentanil increased the consumption of local anaesthetics (80.2 +/- 34 mg; P < 0.05) and the degree of motor blockade. CONCLUSION: Despite recent studies indicating that bupivacaine and ropivacaine may not be equipotent, both local anaesthetics provided equi-effective analgesia at equal doses without a difference in side-effects.     

Comparison of hydraulic and hemolytic properties of different impeller designs of an implantable rotary blood pump by computational fluid dynamics

A mixed-flow blood pump for long-term applications has been developed at the Helmholtz-Institute in Aachen, Germany. Central features of this implantable pump are a centrally integrated motor, a blood-immersed mechanical bearing, magnetic coupling of the impeller, and a shrouded impeller, which allows a relatively wide clearance. The aim of the study was a numerical analysis of hydraulic and hemolytic properties of different impeller design configurations. In vitro testing and numerical simulation techniques (computational fluid dynamics [CFD]) were applied to achieve a comprehensive overview. Pressure-flow charts were experimentally measured in a mock loop in order to validate the CFD data. In vitro hemolysis tests were performed at the main operating point of each impeller design. General flow patterns, pressure-flow charts, secondary flow rates, torque, and axial forces on the impeller were calculated by means of CFD. Furthermore, based on streak line techniques, shear stress (stress loading), exposure times, and volume percentage with critical stress loading have been determined. Comparison of CFD data with pressure head measurements showed excel-lent agreement. Also, impressive trend conformity was observed between in-vitro hemolysis results and numerical data. Comparison of design variations yielded clear trends and results. Design C revealed the best hydraulic and hemolytic properties and was chosen as the final design for the mixed-flow rotary blood pump.     

Test-retest reliability of temporal and spatial gait characteristics measured with an instrumented walkway system (GAITRite<Superscript>®</Superscript>)

Background

The purpose of this study was to determine the test-retest reliability of temporal and spatial gait measurements over a one-week period as measured using an instrumented walkway system (GAITRite^®).

Methods

Subjects were tested on two occasions one week apart. Measurements were made at preferred and fast walking speeds using the GAITRite^® system. Measurements tested included walking speed, step length, stride length, base of support, step time, stride time, swing time, stance time, single and double support times, and toe in-toe out angle.

Results

Twenty-one healthy subjects participated in this study. The group consisted of 12 men and 9 women, with an average age of 34 years (range: 19 – 59 years). At preferred walking speed, all gait measurements had ICC's of 0.92 and higher, except base of support which had an ICC of 0.80. At fast walking speed all gait measurements had ICC's above 0.89 except base of support (ICC = 0.79),

Conclusions

Spatial-temporal gait measurements demonstrate good to excellent test-retest reliability over a one-week time span.

     

Bax deficiency rescues resection-induced enterocyte apoptosis in mice with perturbed EGF receptor function

BACKGROUND: Adaptation after massive smallbowel resection (SBR) is associated with increased cell turnover, increased rates of enterocyte proliferation, and apoptosis. Epidermal growth factor receptor (EGFR) inhibition attenuates adaptation and increases apoptosis. Intestinal levels of bax appear to correlate with EGFR signaling. This study tested the hypothesis that bax is required for the exaggerated postresection apoptosis induced by perturbed EGFR signaling. METHODS: Waved-2 mice with impaired EGFR signaling were crossbred with bax-null mice. Offspring were subjected to either 50% proximal SBR or sham operation (bowel transection and reanastomosis). After 7 days, parameters of adaptation (villus height, wet weight), proliferation (% Ki-67 immunostaining of crypt cells), and apoptosis (# apoptotic bodies per crypt) were recorded in the remnant ileum. RESULTS: Enterocyte apoptosis was increased in waved-2 mice and prevented in bax-null mice after SBR. The accelerated apoptosis in the waved-2 mice was rescued in the context of deficient bax expression. Other parameters of adaptation were restored in the bax-null/waved-2 mice. CONCLUSION: Bax is required for the induction of postresection enterocyte apoptosis. Defective EGFR signaling augments resection-induced enterocyte apoptosis via a mechanism that also requires bax expression. These data implicate a link between EGFR signaling and bax in the genesis of postresection apoptosis and adaptation.     

Rectal perforation after AxiaLIF instrumentation: case report and review of the literature

Background contextBowel perforation is an uncommon complication of posterior spinal surgery. The AxiaLIF transsacral instrumentation system has been used for the treatment of L5–S1 spondylolisthesis and degenerative disc disease since its introduction in 2005 as a potentially less invasive alternative to traditional anterior or posterior interbody fusion.PurposeIn this article, we report a case of a rectal perforation as a complication of placement of the AxiaLIF instrumentation system that was successfully treated without the removal of the device.Study designCase report.MethodsThe patient presented with progressive back pain and sepsis 3 weeks after an L5–S1 fusion done with the AxiaLIF technique at an outside facility. The patient was managed with antibiotic therapy and a diverting ileostomy, without the removal of the AxiaLIF device.ResultsOver the next year, she had symptoms indicative of nonunion of the operated level and breakdown at the adjacent level, which were confirmed with imaging. She underwent revision posterior spinal fusion without the removal of the AxiaLIF device. Eighteen months after the AxiaLIF device was placed, the patient continued to demonstrate no signs of infection recurrence.ConclusionsDelayed presentation of rectal perforation with a subsequent anaerobic sepsis is a potential complication of the presacral approach to the L5–S1 disc space. Recognition and treatment with fecal diversion and long-term intravenous antibiotics is an alternative to device removal and sacral reconstruction.     

Mucosal loss with increased expression of IL-6, IL-8, and COX-2 in a formula-feeding only neonatal rat model of necrotizing enterocolitis

Introduction

The aim of our study is to establish a reliable neonatal rat model by formula feeding only for evaluation of early surgical intervention on the course of experimental necrotizing enterocolitis (NEC).

Material and methods

Newborn Sprague–Dawley rats were divided into 50 breast-fed (group 1) and 38 formula fed (Similac/Esbilac, group 2) animals. The pups were sacrificed on the 4th, 5th, and 6th day of life and the terminal intestine examined for macroscopic and histologic changes as well as cytokine expression.

Results

The histological mucosal damage was significantly higher of group 2 compared to group 1. The area of the vital mucosa of group 2 was significantly (58.57%, p < 0.001) lower compared to group 1 (75.12%). The mRNA expression of the inflammatory cytokines IL-6, IL-8 and COX-2 was significantly 2-, 5- and 10-fold increased in group 2 compared to group 1.

Discussion

Formula fed newborn rats displayed an inflammatory enterocolitis similar to human NEC. Our study demonstrates a significant loss of mucosa in animals with NEC having increased expression levels of IL-6, IL-8 and COX-2. Mucosal loss appears to be a distinct feature of experimental NEC and has to be correlated with the human disease.