Effects of L-ascorbic acid supplementation on dieldrin toxicity in rats

Chronic dieldrin administration to rats (5 mg/kg/day) produced pathological changes in liver and kidney tissues. Dieldrin treated rats showed high levels of liver ascorbic acid and increased activities of inorganic pyrophosphatase in brain and glucose-6-phosphatase in liver. The activities of Mg²⁺-ATPase in liver and acetylcholinesterase in brain were decreased under toxic doses of dieldrin. L-Ascorbic acid supplements in treated animals could partially prevent the pathological alterations, as observed histologically in liver and kidney tissues. Administration of this vitamin could also prevent alterations in some enzyme activities produced by toxic dieldrin doses.     

Bedside hemodynamic monitoring. Its value in the diagnosis of tamponade complicating cardiac surgery.

Cardiac tamponade may be a difficult clinical diagnosis in the early postoperative period in patients undergoing open-hear surgery, particularly when the anterior or lateral pericardium is left open. Bedside monitoring of intracardiac pressures and determination of a "pressure plateau" between right atrial, right ventricular diastolic, pulmonary arterial diastolic, and pulmonary capillary wedge pressures are useful in the early diagnosis of cardiac tamponade. The value of such hemodynamic monitoring in the diagnosis and treatment of cardiac tamponade in three patients with aorta-coronary artery bypass surgery in the early postoperative period is reported. Appropriate therapy, carried out on the basis of these studies, minimized the occurrence of further morbidity or possible death.     

Weighing the evidence for cross over in neglect

When patients with left-sided neglect are asked to bisect horizontal lines, they tend to place their marks to the right of the line's objective mid-point. However, when asked to bisect short lines they are either more accurate or paradoxically cross over and place their marks to the left of the objective mid-point. Previous explanations of the cross over phenomenon have considered specific aberrations of spatial attention. However, these explanations make no predictions about judgments of non-spatial stimuli. Two patients with right brain damage were asked to judge weights placed on both hands simultaneously. They were biased in reporting weights on the right as being heavier than those on the left. This rightward bias changed with lighter pairs of weights presented in the context of equal reference weights. In one patient the directional bias was eliminated and in the other the bias was reversed so that she was more likely to report the left weight as heavier than the right. These data suggest that a phenomenon analogous to cross over in line bisections also occurs with judgments of non-spatial stimuli. Representations of stimuli appear to be influenced by features of the stimuli encountered on-line and by memory traces of similar stimuli encountered previously. With an attentional deficit, memory traces influence the magnitude of the representation derived on-line disproportionately.     

Effect of a selective cyclooxygenase-2 inhibitor, nimesulide, on the growth of lung tumors and their expression of cyclooxygenase-2 and peroxisome proliferator- activated receptor-gamma.

PURPOSE: The objectives of this study were to evaluate the effect of a cyclooxygenase (COX)-2 inhibitor, nimesulide, on the growth inhibition of s.c. human lung A549 adenocarcinoma tumors and to assess the effect of nimesulide on the expression of COX-2 and peroxisome proliferator-activated receptor (PPAR)-gamma in lung tumors harvested from mice. EXPERIMENTAL DESIGN: Female nu/nu mice were xenografted with s.c. A549 lung tumors, and 1 day after tumor implantation, the mice were fed with a diet containing nimesulide at 250-1500 ppm doses. Tumor dimensions were monitored twice weekly, and tumor samples isolated from mice were used to determine prostaglandin E(2) (PGE(2)) levels by enzyme immunoassay, expression of COX-2 and PPAR-gamma by Western blotting and immunohistochemistry. Furthermore, the induction of apoptosis in tumor specimens was determined by terminal deoxynucleotidyl transferase-mediated nick end labeling staining. RESULTS: Nimesulide treatment showed a dose-dependent growth-inhibitory effect of A549 tumors with a maximum of 77.7% inhibition at 1500 ppm of nimesulide. Western blotting experiments showed similar expression of COX-2 in both control and nimesulide (250-1500 ppm)-treated mice tumor tissues. PPAR-gamma was found to be overexpressed as a result of 1500 ppm nimesulide treatment and was not detected in tumors from control or 250-1000 ppm nimesulide-treated mice. Nimesulide (1500 ppm) significantly reduced intratumor PGE(2) levels (P < 0.001) and induced apoptosis in 25% of tumor cells as compared with control tumors. CONCLUSIONS: Nimesulide (1500 ppm) induced growth inhibition of A549 lung tumors is associated with the reduction of intratumor PGE(2) levels but without affecting the expression of COX-2. Nimesulide-induced enhancement of the expression of PPAR-gamma may also contribute to its antitumor effect, which needs to be further investigated.     

Effect of nitric oxide on mortality of mice after whole body hyperthermia.

The objective of this study is to find the role of nitric oxide (NO) in the haemodynamics of mice subjected to heat stress caused by Whole Body Hyperthermia (WBH) treatment. L-arginine (L-arg), a natural substrate for NO synthase (NOS), N-nitro-L-arginine methyl ester (L-NAME), a preferential inhibitor of endothelial NOS, and dexamethasone, a preferential inhibitor of inducible NOS, have been used to study the role of NO in thermal injury caused by WBH treatment. Nitrite in plasma and mortality of Swiss male mice subjected to WBH treatment induced by radiant heat (40 degrees C fo 1 h at 50-55% relative humidity), were monitored in mice pre-treated with either L-NAME, dexamethasone or L-arg. A batch of mice subjected to 24 h fasting prior to WBH treatment was also used to study the above parameters. Injections with 1.5 mg/kg or above of L-NAME just before WBH treatment, induced mortality in mice, with a corresponding drop in plasma nitrite values. L-arg (8 mg/kg) pre-treatment reversed the killing caused by L-NAME in WBH treated mice. L-arg (60 mg/kg) pre-treatment induced mortality in mice subjected to WBH treatment. In the fasted group, a very low dose of L-arg (8 mg/kg) given before WBH treatment led to a significant increase in plasma nitrite levels. In both the normal and fasted groups of mice, 120 mg/kg of L-arg pre-treatment resulted in a sharp increase in plasma nitrite values and subsequent death of mice. The results throw up an important finding, in that the interaction of elevated body temperature, with either a decrease or over production of nitrite oxide, leads to modulation of thermal injury of mice, caused by WBH treatment.     

Surgical management of complications after transcatheter closure of an atrial septal defect or patent foramen ovale

OBJECTIVE: During recent years, transcatheter closure has become an alternative to operations for the treatment of atrial septal defects and patent foramen ovale. However, this procedure may be unsuccessful or complicated and requires surgical treatment. METHODS: We retrospectively analyzed the outcomes of patients who needed surgical treatment after failed or complicated transcatheter closure of an atrial septal defect or a patent foramen ovale. RESULTS: Between April 1994 and March 1999, 124 patients were treated with transcatheter closure of an atrial septal defect or a patent foramen ovale at our institution. We report the results of 10 (8%) patients of this series who required operations after transcatheter closure attempts. In 8 of these 10 patients a significant shunt caused by malposition or dislocation of the device persisted, leading to surgical closure of the defect. In 2 patients injury of the femoral artery at the puncture site required surgical repair. In one patient the device had to be removed surgically from the iliac vein after retraction. One patient died of left ventricular perforation after dislocation of the device and several surgical attempts to close the left ventricular rupture. All other patients recovered well. CONCLUSION: An operation was required after transcatheter closure of an atrial septal defect or a patent foramen ovale in 8% of patients. After device complications, the atrial septal defect and the patent foramen ovale can still successfully be closed surgically with good results and low morbidity. However, serious complications like cardiac perforation may have a fatal outcome. Residual shunt, dislocation, or vascular complications are the most frequent problems that require surgical interventions.     

Improved exposure of isolated perimembranous ventricular septal defects

We describe an alternative step in the transatrial approach to the repair of ventricular septal defects. We temporarily detach the chorda of the obscuring tricuspid valve from its attachment to the septum to expose the ventricular septal defect.     

Epidemiology of Travelers— Diarrhea: Details of a Global Survey

Background Recent epidemiologic data on travelers— diarrhea (TD) are essential for the evaluation of conventional and future prophylactic and therapeutic measures.
Methods To determine the epidemiology, including risk factors, impact and quality-of-life evaluation of TD, a cross-sectional survey was conducted over 12 months at the airports of Mombasa (Kenya), Goa (India), Montego Bay (Jamaica) and Fortaleza (Brazil) by distributing questionnaires to visitors just prior to their flying home. The study period was March 1996 to July 1998.
Results Overall, 73,630 short-term visitors completed a questionnaire. The total diarrhea attack rate varied between a high of 54.6% in Mombasa and a low of 13.6% in Fortaleza, but only between 31.5% and 5.4% of all travelers had classic TD. The 14-day incidence rates varied between 19.5% and 65.7%. Few travelers meticulously avoided potentially dangerous food items, although in India and Kenya most travelers avoided those considered most dangerous. Risk factors were stays exceeding 1 week, age between 15 and 30 years, and residence in the UK. The impact, measured as incapacity or quality-of-life scores, was very considerable.
Conclusions TD continues to affect vacationers and business travelers as frequently as it did some 20 years ago. Compliance with recommendations to reduce exposure to pathogens by avoiding dangerous food items is poor among travelers from all countries. Implementation of food safety education programs may be difficult to achieve.