Superior vena cava syndrome and syncope in an implantable cardioverter defibrillator recipient.

We describe the case of a recipient of an implantable cardioverter defibrillator with multiple syncopal episodes due both to superior vena cava obstruction and electrical instability. These complications occurred in the presence of two transvenous implantable cardioverter defibrillator leads. The patient has been managed conservatively with anticoagulants and new antiarrhythmic drugs with improvement in both his clinical problems.     

Genetic ecotoxicology I: DNA integrity and reproduction in mosquitofish exposed in situ to radionuclides

Female mosquitofish (Gambusia affinis) were collected from two sites located on the US Department of Energy's Oak Ridge Reservation that are contaminated with 137Cs, 90Sr, other radionuclides and chemical genotoxicants. Fish from non- radionuclide contaminated environments located off the reservation were also collected. DNA, extracted from liver tissue and blood cells, was examined by gel electrophoresis for structural damage in the form of strand breakage. In general, the level of DNA strand breaks was elevated in fish from radionuclide-contaminated sites with observed differences in the number and type of strand breaks between liver tissue and blood cells. The number of malformed embryos was higher in fish at the contaminated sites, and varied with season. Fecundity was negatively correlated with the level of double strand breaks in the DNA of fish from one contaminated site. Females with broods that included malformed embryos had more DNA strand breakage than those that did not; and furthermore, a threshold effect was observed between the occurrence of malformed embryos and the presence of double strand breaks in the DNA of the mother. These findings have implications for both ecological risk assessment and evolutionary ecology     

Fixation of complex proximal humeral fractures in elderly patients with a locking plate: A retrospective analysis of radiographic and clinical outcome and complications

Purpose: The optimal surgical treatment of displaced type B and C fractures of the proximal humerus in the elderly remains controversial. Good clinical results have been reported by plating these fractures as well as a high rate of complications. Our retrospective study aims to evaluate clinical recovery and complications using the S3 locking plate in elderly patients. Methods: Fifty-one patients older than 65 years of age, with a complex proximal humeral fracture type B or C (AO classification system), were included. Patients have been followed up for a minimum of 12 months. We assessed callus formation, radiological results, clinical outcome (according to the Constant Shoulder Score System) and complications. Any difference in the clinical recovery among the 2 types of fracture pattern (B and C) was investigated. Results: The mean time of fracture healing was 12.4 weeks. The mean Constant score at 3, 6 and 12 months was 68, 73 and 75 respectively. No statistically significant difference in the clinical outcome was observed between the B and C fracture patterns (p > 0.05). We noticed an overall of 5 complications (9.8%). There was no need to revision any of the implants. Conclusion: Anatomic reduction and proper plate positioning are essential for minimizing implantrelated complications. In our experience the S3 angular stability system offers a proper osteosyntesis and a good clinical recovery with a low rate of complications.     

Coronary and peripheral blood flow changes following biventricular pacing and their relation to heart failure improvement.

AIMS: To study the effect of cardiac resynchronization therapy (CRT) on coronary and peripheral arterial circulation and to assess whether their changes are related to the improvement in patients' functional capacity and prognostically important biochemical markers. METHODS AND RESULTS: Twenty-five patients were studied (New York Heart Association classes III and IV, left ventricular ejection fraction <35%, QRS>120 ms, mean age 66 +/- 2.1 years). Coronary blood flow (CBF), forearm blood flow (FBF), and their reserve were measured by transoesophageal echocardiography (in cm/s) and venous occlusion plethysmography (in mL/100 mL/min) at baseline and following 3 months of CRT. N-terminal-pro-brain natriuretic peptide (Nt-pro-BNP) and serum adhesion molecules, sICAM-1 and sVCAM-1 levels were also assessed. CRT induced a non-significant increase in resting CBF (baseline vs. CRT: 52.1 +/- 5.5 vs. 58.2 +/- 3.6, P: NS), whereas hyperaemic CBF was increased by CRT (baseline vs. CRT: 67.8 +/- 6.8 vs. 79.8 +/- 6.2, P < 0.05). Significant increases were observed in resting FBF (baseline vs. CRT: 1.6 +/- 0.2 vs. 2.6 +/- 0.2, P < 0.05) and hyperaemic FBF (baseline vs. CRT: 2.1 +/- 0.2 vs. 3.2 +/- 0.3, P < 0.05). The per cent difference in hyperaemic FBF was related to the per cent change in Nt-pro-BNP (r = -0.71, P < 0.05) and the per cent improvement in exercise duration (r = 0.80, P < 0.05). CONCLUSION: CRT induces favourable changes in coronary and peripheral arterial function. Changes in peripheral blood flow are related to patients' improvement and may be prognostically significant.     

Splenectomy for thrombocytopenia in chronic lymphocytic leukemia

The role of peripheral platelet destruction as a reversible etiology of thrombocytopenia in chronic lymphocytic leukemia (CLL) was evaluated in nine patients with CLL and refractory thrombocytopenia who underwent splenectomy. The patients' ages ranged from 54 to 74 years. Progressive thrombocytopenia refractory to antineoplastic agents and corticosteroids had been present for a mean of 23.4 months. The platelet counts were 4,000-57,000/microliter, and were generally higher in those patients with larger spleens. The spleens ranged from 180 to 4050 gm. Seven patients responded completely to splenectomy, achieving platelet counts greater than 150,000/microliter, and in one other patient, the count rose to greater than 100,000/microliter. The platelet count of one patient failed to respond to surgery. Those patients with massive splenomegaly developed higher, more rapidly rising platelet counts postoperatively. No operative mortality was encountered. Median hospitalization was seven postoperative days. All patients experienced an increased sense of well-being. Median follow-up time is 9 months.     

The Mediating Role of Passion in the Relationship of Exercise Motivational Regulations with Exercise Dependence Symptoms

The present study examined the mediating role of obsessive passion in the relationship of introjected regulation to exercise with exercise dependence symptoms. A cross-sectional design was used. Questionnaires were administered in the context of private fitness centers and were completed before initiation of that day’s exercise activities. Using non-probability sampling, 549 regular Greek exercise participants, men and women (approximately 70 % response rate), aged 18 to 61 years, completed the questionnaires. The Exercise Dependence Scale-Revised (Symons-Downs et al. 2004) was used to measure exercise dependence symptoms; the Passion Scale (Vallerand et al. 2003) was used to measure harmonious and obsessive passion for exercise; and the Behavioral Regulation in Exercise Questionnaire-2 (Markland and Tobin 2004) was used to measure types of behavioral regulations in exercise. Obsessive passion mediated the relationship between introjected regulation and exercise dependence symptoms (CFI?=?0.91–0.95, RMSEA?=?0.05-06). The present findings provided cross-sectional support to the mediating role of obsessive passion in the relationship of introjected regulation to exercise with exercise dependence symptoms.     

Comparative acute and combinative toxicity of aflatoxin B1 and fumonisin B1 in animals and human cells.

Aflatoxin B(1) (AFB(1)) and fumonisin B(1) (FB(1)) are important food-borne mycotoxins. The co-contamination of food stuffs with these two mycotoxins is well known and has been possibly implicated in the development of human hepatocellular carcinoma in high risk regions around the world. In this study the acute and combinative toxicity of AFB(1) and FB(1) were tested in F-344 rats, mosquitofish (Gambusia affinis), immortalized human hepatoma cells (HepG2) and human bronchial epithelial cells (BEAS-2B). Preliminary experiments were conducted in order to assess the acute toxicity and obtain LD(50), LC(50) and IC(50) values for individual toxins in each model, respectively. This was followed by testing combinations of AFB(1) and FB(1) to obtain LD(50), LC(50) and IC(50) values for the combination in each model. All models demonstrated a significant dose response in relation to toxin treatment. The potency of the mixture was gauged through the determination of the interaction index metric. Results of this study demonstrate that these two toxins interacted to produce alterations in the toxic responses with a strong additive interaction noted in the cases of F344 rats and mosquitofish. It can be gathered that this combination may pose a significant threat to public health and further research needs to be completed addressing alterations in metabolism and detoxification that may influence the toxic manifestations in combination. These results will provide foundational knowledge for future studies on long-term combinative toxic and health effects of these mycotoxins.     

Effect of nitrite on endothelial function in isolated lung

Nitrated tyrosine, implicated in protein dysfunction, is increased in various tissues in association with diverse pathological processes. Angiotensin converting enzyme (ACE) is a luminal vascular endothelial enzyme whose dysfunction is an early sign of endothelial injury. ACE contains a tyrosine critical for its enzymatic activity. Others have shown that nitrite exacerbates the ACE dysfunction of cultured endothelial cells in contact with activated polymorphonuclear neutrophils (PMN). We hypothesized that exogenous nitrite would enhance endothelial ACE dysfunction associated with PMN activation in the isolated lung. Rats received lipopolysaccharide (LPS) 2 h prior to isolated lung perfusion with Ficoll containing buffer. Either formyl-Met-Leu-Phe (fMLP, 10(-7) M) or phorbol myristate acetate (PMA, 10(-7) M) was used to activate PMN in lungs treated or not treated with 300-microM nitrite. A first pass indicator dilution method and first order reaction kinetics were used to determine ACE activity, while lung Ficoll content served as an index of vascular permeability. Both fMLP and PMA decreased endothelial ACE activity and increased pulmonary artery pressure, edema and vascular permeability. Exogenous nitrate did not potentiate the decrease in ACE activity, the lung injury or nitrotyrosine immunoreactivity of lung homogenates. In contrast to observations in cultured endothelial cells, our findings in the whole lung are compatible with the speculation of others that the rat lung has an unidentified factor, which minimizes accumulation of nitrated proteins.     

Genetic Ecotoxicology III: the Relationship Between DNA Strand Breaks and Genotype in Mosquito Fish Exposed to Radiation

DNA polymorphism in mosquito fish (Gambusia affinis), as revealed by RAPD (randomly amplified polymorphic DNA) and allozyme analysis, was compared to relative amounts of DNA strand breakage in blood and liver tissues. Mosquito fish were exposed to radionuclide contamination in situ and to X-rays in the laboratory. The types of RAPD metrics used were the number of RAPD bands per individual and the frequency of certain RAPD bands. In a previous study, it was noted that in some instances the number of RAPD bands and the frequency of certain RAPD bands were elevated in radionuclide-contaminated sites relative to reference sites. In the present study, it was found that the median molecular length (MML) of the DNA (which is inversely proportional to the amount of DNA strand breakage) was correlated in several cases to the number of RAPD bands per individual. In addition, for those RAPD bands that occurred at a higher frequency in mosquito fish from radionuclide-contaminated sites, DNA strand breakage was often lower for those fish with than without these RAPD bands. RAPD data obtained on mosquito fish exposed to X-rays in the laboratory paralleled those from the field. Furthermore, analysis showed that heterozygotes for the allozyme locus nucleoside phosphorylase were more prevalent in radionuclide-contaminated sites and had fewer DNA strand breaks than did homozygotes. These results provide additional evidence that changes in population genetic structure of mosquito fish exposed to a genotoxicant (radiation) can be detected at the DNA level.