Pulsatile ventricular assist device with pericardial inner lining

Preserved pericardium in contact with blood is not thrombogenic, therefore avoiding the use of anticoagulants, and has excellent mechanical properties. Our objective is to take advantage of these characteristics and build a pulsatile ventricular assist device (VAD) with pericardium used as the inner lining of the blood chamber. A mold is used for the tanning of the pericardium, rendering it with an exact shape. A flexible polymeric structure is designed to serve as a base for the pericardium, guiding it and limiting its rate of strain. It consists of two halves, which when outfitted with the interior pericardium lining and connected to each other, form the blood chamber. This assembly is housed in rigid polyvinyl chloride (PVC) shells making up the air chamber for the pneumatic activation. Valves are likewise made of pericardium. Sealing of the chambers was tested statically up to 300 mm Hg with no air or fluid leakage. The device was tested for 60 continuous days in a mock loop, demonstrating hydrodynamic performance adequate for ventricular assist. Micrographs (confocal laser and scanning electron microscopy) were obtained of several pericardium areas, especially on the flexing regions that are a transition between the wet and dry regions. No sign of damage to the pericardium was observed either with the naked eye or at the microscopic level. From the hydraulic performance and materials viewpoints, a completely pericardium-lined pulsatile VAD displaying a polymeric structure that avoids unpredictable bending and limits strain is feasible. The results warrant further studies regarding biocompatibility and strength advantages.     

Mechanical behavior and stability of the internal membrane of the InCor ventricular assist device

Abstract: This paper describes and analyzes the mechanical behavior of the internal membrane of the InCor VAD (Heart Institute [InCor], University of São Paulo, Brazil), applying the knowledge and tools of structural engineering analysis. This membrane plays an important role in the operation of the ventricular assist device (VAD) because it separates the blood chamber from the pneumatic one, transmitting the pneumatic load to the blood, thus making the desired blood flow possible. The loading repeats itself every time the VAD beats. Therefore the performance, reliability, and durability of the membrane are critical for the performance of the VAD. The mathematical model is based on the large deflection theory of thin shells and on the finite element method. The snap‐through instability phenomenon, which is responsible for transmission of the pneumatic load to the blood, was observed in the membrane both when modeled mathematically and experimentally. Principal stresses and strain distributions were obtained with this model at certain load levels along the pre‐ and postbuckling paths.     

Oral treatment of crusted scabies with ivermectin: report of two cases

Oral treatment with ivermectin of crusted (Norwegian) scabies in two immunosuppressed patients is reported. There was resolution of symptoms and signs of the cutaneous parasitosis on administration of 18-36 mg ivermectin (total doses) in 2- and 3-week periods of treatment, with remission periods of 3 and 4 months, respectively.     

Evidence of Epstein-Barr virus infection in ulcerative colitis

BACKGROUND AND AIM: The aetiology of ulcerative colitis is still controversial, however, recent studies have emphasised the possible role of infectious agents or ingested substances and their breakdown products, which might activate immune-mediated mechanisms eventually leading to tissue damage. Aim of this investigation was to ascertain the occurrence and the potential role of Epstein-Barr virus infection in large bowel mucosa of ulcerative colitis patients. PATIENTS AND METHODS: Twenty-three biopsies and six total colectomies from 17 patients were analysed for the expression of Epstein-Barr virus proteins and RNAs. Polymerase chain reaction experiments were also carried out to detect Epstein-Barr virus DNA. For comparison, ten biopsies from patients with Crohn's disease, ten biopsies from patients with different types of colitis, seven biopsies and five surgical margins of normal colonic mucosa from the small and large bowels were studied (controls). RESULTS: Six biopsies and four colectomies from seven ulcerative colitis patients showed scattered lymphocytes expressing nuclear EBER 1-2 and harbouring polymerase chain reaction-amplifiable Epstein-Barr virus-DNA. In some cases, linear viral DNA (typical of lytic Epstein-Barr virus infection) was also found. Epithelial cells were invariably negative in all cases. All control tissues from non-ulcerative colitis patients were also invariably non-reactive. CONCLUSION: Evidence of Epstein-Barr virus infection in the mucosal inflammatory cells of ulcerative colitis patients suggests a possible role of this virus in the chronicity of ulcerative colitis.     

A prospective study comparing paroxetine alone versus paroxetine plus sildenafil in patients with premature ejaculation

PURPOSE: We compared the efficacy of paroxetine alone and combined with sildenafil in patients complaining of premature ejaculation. MATERIALS AND METHODS: Enrolled in this study were 80 consecutive potent men 19 to 47 years old (mean age 34) with premature ejaculation but without any obvious organic cause. Pretreatment evaluation included a history, self-administration of the International Index of Erectile Function (IIEF) questionnaire, physical examination and the Meares-Stamey test to exclude genital tract infection. The initial 40 patients received 10 mg. paroxetine daily for 21 days and then 20 mg. as needed, that is 3 to 4 hours before planned sexual activity, for 6 months (group 1). The other group of 40 men received 10 mg. paroxetine daily for 21 days and then 20 mg. as needed plus 50 mg. sildenafil as needed, that is 1 hour before planned sexual activity, for 6 months (group 2). Patients were followed 3 and 6 months after beginning therapy and were evaluated using several general assessment questions, IIEF and ejaculatory latency time. RESULTS: Mean ejaculatory latency time +/- SE in group 1 was 0.33 +/- 0.04, 3.7 +/- 0.10 (p <0.01) and 4.2 +/- 0.03 (p <0.01) minutes at baseline, 3 and 6-month followup, while in group 2 it was 0.35 +/- 0.03, 4.5 +/- 0.07 (p <0.01) and 5.3 +/- 0.02 (p <0.001) minutes, respectively. When improvement in ejaculatory latency time was compared in the 2 groups, group 2 results proved to be significantly greater (p <0.05). Baseline, and 3 and 6-month mean intercourse satisfaction domain values of the IIEF were 9, 11 and 11 (p = 0.09, not significant), and 9, 11 and 14 (p <0.05) in groups 1 and 2, respectively. Group 2 patients reported significantly greater intercourse satisfaction than those in group 1 (p <0.05). At baseline, 3 and 6 months there was a mean of 0.9 +/- 0.1, 1.7 +/- 0.3 (not significant) and 2.5 +/- 0.3 (p <0.01) coitus episodes weekly in group 1, and 1 +/- 0.2, 2.3 +/- 0.3 (p <0.01) and 3.2 +/- 0.1 (p <0.001) in group 2, respectively. Group 2 patients reported a significantly higher number of coitus episodes weekly (p <0.05). Side effects in the 40 group 1 cases included anejaculation in 1 (2.5%), gastrointestinal upset and/or nausea in 5 (12.5%), headache in 4 (10%) and decreased libido in 2 (5%). Side effects in the 40 group 2 cases included anejaculation in 1 (2.5%), headache in 8 (20%), gastrointestinal upset and/or nausea in 6 (15%) and flushing in 6 (15%). Group 2 patients reported significantly more headaches (p <0.01) and flushing episodes (p <0.001) than those in group 1. After 6 months of treatment 33 men (82.5%) in group 1 and 36 (90%) in group 2 were willing to continue therapy (not significant). CONCLUSIONS: Paroxetine combined with sildenafil appears to provide significantly better results in terms of ejaculatory latency time and intercourse satisfaction versus paroxetine alone in potent patients with premature ejaculation. However, combined treatment is associated with a mild increase in drug related side effects.     

Toxic metals (Pb and Cd) and their respective antagonists (Ca and Zn) in infant formulas and milk marketed in Brasilia, Brazil

In non-ideal scenarios involving partial or non-breastfeeding, cow's milk-based dairy products are mainstream in infant feeding. Therefore, it is important to study the concentrations of potentially neurotoxic contaminants (Pb and Cd) and their respective counteracting elements (Ca and Zn) in infant dairy products. Fifty-five brands of infant formulas and milk sold in Brasilia, Brazil were analyzed. The dairy products came from areas in the central-west (26%), southeast (29%) and south of Brazil (36%) extending as far as Argentina (7%) and the Netherlands (2%). For toxic Pb and Cd, median concentrations in powdered samples were 0.109 mg/kg and 0.033 mg/kg, respectively; in fluid samples median Pb concentration was 0.084 mg/kg, but median Cd concentration was below the limit of detection and overall values were below reference safety levels. However, 62% of these samples presented higher Pb concentration values than those established by FAO/WHO. Although the inverse correlation between Cd and Zn (Spearman r = -0.116; P = 0.590) was not statistically significant, the positive correlation between Ca and Pb was (Spearman r = 0.619; P < 0.0001). Additionally, there was a significant correlation between Pb and Cd. Furthermore, the study also revealed that provision of the essential trace element Zn in infant formulas can provide adequate amounts of the recommended daily requirements. Infant formulas and milk sold for consumption by infants and children can be an efficient tool to monitor neurotoxic metal risk exposure among young children.     

Overview of the toxic effects of titanium dioxide nanoparticles in blood,liver, muscles,and brain of a Neotropical detritivorous fish

The toxicity of titanium dioxide nanoparticles (TiO₂‐NP) in the blood, liver, muscle, and brain of a Neotropical detritivorous fish, Prochilodus lineatus, was tested. Juvenile fish were exposed to 0, 1, 5, 10, and 50 mg L^?1 of TiO₂‐NP for 48 hours (acute exposure) or 14 days (subchronic exposure) to evaluate changes in hematology, red blood cell (RBC) genotoxicity/mutagenicity, liver function (reactive oxygen species (ROS) production, antioxidant responses, detoxification, and histopathology), acetylcholinesterase (AChE) activity in muscles and brain, and Ti bioaccumulation. TiO₂‐NP did not cause genetic damage to RBC, but acutely decreased white blood cells (WBC) and increased monocytes. Subchronically, RBC decreased, mean cell volume and hemoglobin increased, and WBC and lymphocytes decreased. Therefore, NP has the potential to affect immune system and increase energy expenditure, reducing the fish's ability to avoid predator and to resist pathogens. In the liver, acute exposure decreased ROS and increased glutathione (GSH) content, while subchronic exposure decreased superoxide dismutase activity and increased glutathione‐S‐transferase (GST) activity and GSH content. GSH and GST seem to play an essential role in metabolizing NP and ROS, likely increasing hepatocytes' metabolic rate, which may be the cause of observed cell hypertrophy, disarrangement of hepatic cords and degenerative morphological alterations. Although most studies indicate that the kidney is responsible for metabolizing and/or eliminating TiO₂‐NP, this study shows that the liver also has a main role in these processes. Nevertheless, Ti still accumulated in the liver, muscle, and brain and decreased muscular AChE activity after acute exposure, showing neurotoxic potential. More studies are needed to better understand the biochemical pathways TiO₂‐NP are metabolized and how its bioaccumulation may affect fish homeostasis and survival in the environment.     

Zinc Deficiency in Nursing Infants

Zinc deficiency during nursing can occur even in breast-fed infants. Zinc reserves accumulated during fetal development modulate the infant’s susceptibility to zinc deficiency. Improvement of maternal zinc nutrition during pregnancy is the key for infant’s zinc nutritional support and prevention of low-for-lactation-age zinc concentrations of breast-milk.