Underlying Etiology (underlying + etiology)

Distribution by Scientific Domains

Selected Abstracts

Is ,-lipoic acid a scavenger of reactive oxygen species in vivo?

IUBMB LIFE, Issue 6 2008
Evidence for its initiation of stress signaling pathways that promote endogenous antioxidant capacity
Abstract The chemical reduction and oxidation (redox) properties of ,-lipoic acid (LA) suggest that it may have potent antioxidant potential. A significant number of studies now show that LA and its reduced form, dihydrolipoic acid (DHLA), directly scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) species and protect cells against a host of insults where oxidative stress is part of the underlying etiology. However, owing to its limited and transient accumulation in tissues following oral intake, the efficacy of nonprotein-bound LA to function as a physiological antioxidant has been questioned. Herein, we review the evidence that the micronutrient functions of LA may be more as an effector of important cellular stress response pathways that ultimately influence endogenous cellular antioxidant levels and reduce proinflammatory mechanisms. This would promote a sustained improvement in cellular resistance to pathologies where oxidative stress is involved, which would not be forthcoming if LA solely acted as a transient ROS scavenger. 2008 IUBMB IUBMB Life, 60(6): 362,367, 2008 [source]

Recurrent erythema multiforme triggered by progesterone sensitivity

Teresa J. Nasabzadeh
Determining the underlying etiology of recurrent erythema multiforme (EM) can be a difficult endeavor. Although infection with herpes simplex virus (HSV) has been implicated in some cases, the precise trigger of a given patient's recurrent EM often remains elusive. We discuss the case of a woman with a recurrent blistering eruption that was clinically and histopathologically consistent with EM. An investigation into the etiology of the patient's EM suggested that HSV was not the causative factor but instead pointed toward a hormonal influence that we interpret as autoimmune progesterone dermatitis (APD). This case is presented to highlight the importance of considering hormonal triggers in women with recurrent EM that consistently flares during the luteal phase of the menstrual cycle, the point at which serum progesterone levels peak. A brief review of the literature regarding the diagnosis, histopathology, etiology and treatment of APD is further provided. Nasabzadeh TJ, Stefanato CM, Doole JE, Radfar A, Bhawan J, Venna S. Recurrent erythema multiforme triggered by progesterone sensitivity. [source]

Validity of the Spanish version of the Chronic Liver Disease Questionnaire (CLDQ) as a standard outcome for quality of life assessment,

Montserrat Ferrer
The Chronic Liver Disease Questionnaire (CLDQ) measures the impact on quality of life of chronic liver diseases, regardless of underlying etiology. The aim of this study was to develop a Spanish version of the CLDQ, and to assess its acceptability, reliability, validity, and sensitivity to change. The forward and back-translation method by bilingual translators, with expert panel and pilot testing on patients, was used for the adaptation. The final version was self-administered, together with the Short Form-36 Health Survey (SF-36), on 149 consecutive patients with chronic liver disease. Child-Turcotte-Pugh scores were evaluated by a physician. To assess reproducibility and responsiveness the CLDQ was readministered to a subsample of stable patients and to those who had received a liver transplant. Validity was evaluated via exploratory factor analysis, the CLDQ pattern across severity groups, and correlation coefficients with "itching" and SF-36 scores. Cronbach's alpha and Intraclass Correlation Coefficient for CLDQ global score were 0.93 and 0.90, respectively, demonstrating good reliability. Validity was supported by correlations of the CLDQ with SF-36 and "itching," and CLDQ severity gradient (global score means were 5.5, 5.2, 5.0, and 4.5 in patients with no cirrhosis, cirrhosis Child-Turcotte-Pugh A, B, and C, respectively; P = 0.012). Responsiveness was shown by a high CLDQ improvement in patients who had received liver transplant (mean change = ,1.4; P < 0.001). In conclusion, the Spanish CLDQ is reliable, valid, responsive, and equivalent to the original. These findings support its use as a standard outcome for patients with chronic liver diseases within the whole severity range, from "no cirrhosis" to transplant recipients, both in Spanish and international studies. Liver Transpl 12:95,104, 2006. 2005 AASLD. [source]

Impairment of Hepatic Microcirculation in Fatty Liver

ABSTRACT Fatty liver or hepatic steatosis, which is the result of the abnormal accumulation of triacylglycerol within the cytoplasm of hepatocytes, is a common histological finding in human liver biopsy specimens that is attributed to the effects of alcohol excess, obesity, diabetes, or drugs. There is a general consensus that fatty liver compromises hepatic microcirculation, the common exchange network upon which hepatic arterial and portal inflows converge, regardless of underlying etiology. A significant reduction in hepatic microcirculation has been observed in human fatty donor livers and in experimental models of hepatic steatosis. There is an inverse correlation between the degree of fat infiltration and both total hepatic blood flow and flow in microcirculation. Fatty accumulation in the cytoplasm of the hepatocytes is associated with an increase in the cell volume that reduces the size of the hepatic sinusoid space by 50% compared with a normal liver and may result in partial or complete obstruction of the hepatic sinusoid space. As a result of impaired hepatic microcirculation, the hepatocytes of the fatty liver have reduced tolerance against ischemia-reperfusion injury, which affects about 25% of the donors for liver transplantation because severe steatosis is associated with a high risk of primary nonfunction after liver transplantation. [source]

The inhibitory effect of a chewing task on a human jaw reflex

MUSCLE AND NERVE, Issue 6 2010
Pauline Maillou BDS
Abstract This study was undertaken to investigate whether an inhibitory jaw reflex could be modulated by experimentally controlled conditions that mimicked symptoms of temporomandibular disorders. Reflecting on previous work, we anticipated that these conditions might suppress the reflex. Electromyographic recordings were made from a masseter muscle in 18 subjects, while electrical stimuli were applied to the upper lip. An inhibitory reflex wave (mean latency 47 ms) was identified and quantified. Immediately following an accelerated chewing task, which in most cases produced muscle fatigue and/or pain, the size of the reflex wave decreased significantly by about 30%. The suppression of inhibitory jaw reflexes by fatigue and pain may result in positive feedback, which may contribute to the symptoms of temporomandibular disorders. Future studies of temporomandibular disorder sufferers will help to determine whether such reflex changes reflect the underlying etiology and/or are a result of the temporomandibular disorder itself. Muscle Nerve, 2010 [source]

Pacemaker and Defibrillator Lead Extraction: Predictors of Mortality during Follow-Up

Background:Extraction of cardiac implantable electric devices is an accepted procedure when systems become infected or malfunction. However, there is an associated morbidity and mortality. We report our 5-year experience and identify predictors of mortality, and long-term follow-up. Methods:We analyzed extraction data from January 2003 to November 2007. Extraction methods used were: locking stylets, telescoping sheaths laser, and femoral work stations. Results:One hundred and eighty-three cases were referred, aged 65 16 years (range 28,83); 76% were males. Mean implant time was 75 months (range 4,312 months) and indications were: pocket infection (48%), nonfunctioning lead (22%), erosion through skin (18%), endocarditis/septicemia (11%), bilateral superior vena cava thrombosis (0.5%), and painful lead (0.5%). The number of leads extracted were 369, with complete removal in 90.7% and partial in 7.6%. There were no intraoperative deaths but five (2.7%) died within the same admission as their extraction from overwhelming sepsis. Twelve deaths (6.6%) occurred during an average follow-up of 965 days (range 40,1670). Multivariate logistic regression demonstrated that C-reactive protein preprocedure was predictive of acute in-hospital mortality. Conclusions:Intravascular lead extraction is a safe and efficient method of removing leads. However, there is a subgroup of patients with systemic sepsis with raised inflammatory markers who are at high risk of in-hospital mortality. Long-term follow-up demonstrates mortality which is a marker of the underlying etiology for device implantation, with heart failure patients particularly at risk. (PACE 2010; 33:209,216) [source]

A Partially Linear Tree-based Regression Model for Multivariate Outcomes

BIOMETRICS, Issue 1 2010
Kai Yu
Summary In the genetic study of complex traits, especially behavior related ones, such as smoking and alcoholism, usually several phenotypic measurements are obtained for the description of the complex trait, but no single measurement can quantify fully the complicated characteristics of the symptom because of our lack of understanding of the underlying etiology. If those phenotypes share a common genetic mechanism, rather than studying each individual phenotype separately, it is more advantageous to analyze them jointly as a multivariate trait to enhance the power to identify associated genes. We propose a multilocus association test for the study of multivariate traits. The test is derived from a partially linear tree-based regression model for multiple outcomes. This novel tree-based model provides a formal statistical testing framework for the evaluation of the association between a multivariate outcome and a set of candidate predictors, such as markers within a gene or pathway, while accommodating adjustment for other covariates. Through simulation studies we show that the proposed method has an acceptable type I error rate and improved power over the univariate outcome analysis, which studies each component of the complex trait separately with multiple-comparison adjustment. A candidate gene association study of multiple smoking-related phenotypes is used to demonstrate the application and advantages of this new method. The proposed method is general enough to be used for the assessment of the joint effect of a set of multiple risk factors on a multivariate outcome in other biomedical research settings. [source]

Protective mechanisms of the common fibular nerve in and around the fibular tunnel: A new concept

Ramadan M. El Gharbawy
Abstract The most frequent site at which the common fibular nerve is affected by compression, trauma, traction, masses, and surgery is within and around the fibular tunnel. The aim of this study was to determine whether there were protective mechanisms at this site that guard against compression of the nerve. Twenty-six lower limbs of 13 preserved adult cadavers (11 males and two females) were used. Proximal to the entrance of the tunnel, three anatomical configurations seemed to afford the required protection for the nerve: reinforcement of the deep fascia; tethering of the common fibular nerve to both the tendon of the biceps femoris and the reinforced fascia; and the particular arrangement of the deep fascia, fibular head, and soleus and gastrocnemius muscles. At the entrance of the tunnel, contraction of the first segment of fibularis longus muscle could afford the required protection. In the tunnel, contraction of the second and third segments of fibularis longus muscle could guard against compression of the nerve. The tough fascia on the surface of fibularis longus muscle and the fascial band within it, which have long been accused of compression of the nerve, may actually be elements of the protective mechanisms. We conclude that there are innate, anatomical protective mechanisms which should be taken into consideration when decompressing the common fibular nerve. To preserve these mechanisms whenever possible, the technique should be planned and varied according to the underlying etiology. Clin. Anat. 22:738,746, 2009. 2009 Wiley-Liss, Inc. [source]