Effect of different anesthetic agents on left ventricular systolic function assessed by echocardiography in hamsters.

Determination of left ventricular ejection fraction (LVEF) using in vivo imaging is the cardiac functional parameter most frequently employed in preclinical research. However, there is considerable conflict regarding the effects of anesthetic agents on LVEF. This study aimed at assessing the effects of various anesthetic agents on LVEF in hamsters using transthoracic echocardiography. Twelve female hamsters were submitted to echocardiography imaging separated by 1-week intervals under the following conditions: 1) conscious animals, 2) animals anesthetized with isoflurane (inhaled ISO, 3 L/min), 3) animals anesthetized with thiopental (TP, 50 mg/kg, intraperitoneal), and 4) animals anesthetized with 100 mg/kg ketamine plus 10 mg/kg xylazine injected intramuscularly (K/X). LVEF obtained under the effect of anesthetics (ISO=62.2±3.1%, TP=66.2±2.7% and K/X=75.8±1.6%) was significantly lower than that obtained in conscious animals (87.5±1.7%, P<0.0001). The K/X combination elicited significantly higher LVEF values compared to ISO (P<0.001) and TP (P<0.05). K/X was associated with a lower dispersion of individual LVEF values compared to the other anesthetics. Under K/X, the left ventricular end diastolic diameter (LVdD) was increased (0.60±0.01 cm) compared to conscious animals (0.41±0.02 cm), ISO (0.51±0.02 cm), and TP (0.55±0.01 cm), P<0.0001. The heart rate observed with K/X was significantly lower than in the remaining conditions. These results indicate that the K/X combination may be the best anesthetic option for the in vivo assessment of cardiac systolic function in hamsters, being associated with a lower LVEF reduction compared to the other agents and showing values closer to those of conscious animals with a lower dispersion of results.

Can course format influence the performance of students in an advanced cardiac life support (ACLS) program?

Advanced cardiac life support (ACLS) is a problem-based course that employs simulation techniques to teach the standard management techniques of cardiovascular emergencies. Its structure is periodically revised according to new versions of the American Heart Association guidelines. Since it was introduced in Brazil in 1996, the ACLS has been through two conceptual and structural changes. Detailed documented reports on the effect of these changes on student performance are limited. The objective of the present study was to evaluate the effect of conceptual and structural changes of the course on student ACLS performance at a Brazilian training center. This was a retrospective study of 3266 students divided into two groups according to the teaching model: Model 1 (N = 1181; 1999-2003) and Model 2 (N = 2085; 2003-2007). Model 2 increased practical skill activities to 75 percent of the total versus 60 percent in Model 1. Furthermore, the teaching material provided to the students before the course was more objective than that used for Model 1. Scores greater than 85 percent in the theoretical evaluation and approval in the evaluation of practice by the instructor were considered to be a positive outcome. Multiple logistic regression was used to adjust for potential confounders (specialty, residency, study time, opportunity to enhance practical skills during the course and location where the course was given). Compared to Model 1, Model 2 presented odds ratios (OR) indicating better performance in the theoretical (OR = 1.34; 95 percentCI = 1.10-1.64), practical (OR = 1.19; 95 percentCI = 0.90-1.57), and combined (OR = 1.38; 95 percentCI = 1.13-1.68) outcomes. Increasing the time devoted to practical skills did not improve the performance of ACLS students.

Can course format influence the performance of students in an advanced cardiac life support (ACLS) program?

Advanced cardiac life support (ACLS) is a problem-based course that employs simulation techniques to teach the standard management techniques of cardiovascular emergencies. Its structure is periodically revised according to new versions of the American Heart Association guidelines. Since it was introduced in Brazil in 1996, the ACLS has been through two conceptual and structural changes. Detailed documented reports on the effect of these changes on student performance are limited. The objective of the present study was to evaluate the effect of conceptual and structural changes of the course on student ACLS performance at a Brazilian training center. This was a retrospective study of 3266 students divided into two groups according to the teaching model: Model 1 (N = 1181; 1999-2003) and Model 2 (N = 2085; 2003-2007). Model 2 increased practical skill activities to 75% of the total versus 60% in Model 1. Furthermore, the teaching material provided to the students before the course was more objective than that used for Model 1. Scores greater than 85% in the theoretical evaluation and approval in the evaluation of practice by the instructor were considered to be a positive outcome. Multiple logistic regression was used to adjust for potential confounders (specialty, residency, study time, opportunity to enhance practical skills during the course and location where the course was given). Compared to Model 1, Model 2 presented odds ratios (OR) indicating better performance in the theoretical (OR = 1.34; 95%CI = 1.10-1.64), practical (OR = 1.19; 95%CI = 0.90-1.57), and combined (OR = 1.38; 95%CI = 1.13-1.68) outcomes. Increasing the time devoted to practical skills did not improve the performance of ACLS students.

Acute chagasic myocardiopathy after orthotopic liver transplantation with donor and recipient serologically negative for Trypanosoma cruzi: a case report.

Chagas disease (American trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi. Chagas disease following solid-organ transplantation has occurred in Latin America. This report presents the occurrence of Chagas disease despite negative serological tests in both the donor and the recipient, as well as the effectiveness of treatment. A 21-year-old woman from the state of Sao Paulo (Brazil) underwent cadaveric donor liver transplantation in November 2005, due to cirrhosis of autoimmune etiology. Ten months after liver transplantation, she developed signs and symptoms of congestive heart failure (New York Heart Association functional class IV). The echocardiogram, which was normal preoperatively, showed dilated cardiac chambers, depressed left ventricular systolic function (ejection fraction = 35%) and moderate pulmonary hypertension. Clinical investigation discarded ischemic heart disease and autoimmune and other causes for heart failure. Immuno fluorescence (immunoglobulin M and immunoglobulin G) and hemagglutination tests for T cruzi were positive, and abundant T cruzi amastigotes were readily identified in myocardial biopsy specimens. Treatment with benznidazole for 2 months yielded an excellent clinical response. At the moment of submission, the patient remains in functional class I. This case highlighted that more appropriate screening for T cruzi infection is mandatory in potential donors and recipients of solid-organ transplants in regions where Chagas disease is prevalent. Moreover, it stressed that this diagnosis should always be considered in recipients who develop cardiac complications, since negative serological tests do not completely discard the possibility of disease transmission and since good results can be achieved with prompt trypanocidal therapy.

[Hyperhomocysteinemia in chronic renal failure.]. / L'iperomocisteinemia nell'insufficienza renale cronica: aspetti clinici, nutrizionali e tossicità.

Chronic renal failure (CRF) is frequently associated with increased plasma levels of homocysteine (Hcy), an amino acid that can be considered a new uremic toxin according to recent evidence. Studies on Hcy described first homocystinuria, an inherited disease characterized by high plasma Hcy levels and premature cardiovascular disease, resulting in high mortal-ity rates. Hyperhomocysteinemia was then shown to be associated with cardiovascular events both in the general population and in CRF patients. Hcy is a sulfur amino acid derived from dietary methionine, an essential amino acid. Methionine is condensed with ATP to form S-adenosylmethionine (AdoMet), the universal methyl donor in transmethylation reactions. The AdoMet demethylated product is S-adenosylhomocysteine (AdoHcy), which is the direct precursor of Hcy in vivo. Hcy is toxic for the endothelium, it enhances vascular smooth muscle cell proliferation, increases platelet aggregation, and acts on the coagulation cascade and fibrinolysis. Several mechanisms have been discussed to explain Hcy toxicity. Hcy levels increase as renal function declines and progresses to ESRD; the causes of hyperhomocysteinemia are still unclear. Studies in humans show that renal metabolic extraction depends on renal plasma flow; in addition, an alteration of the extrarenal metabolic clearance, depending on uremic toxins, may occur. Among the consequences of hyperhomocysteinemia in renal failure are: impaired protein methylation, with altered protein repair processes; DNA hypomethylation, with an alteration in the allelic expression of genes regulated through methylation; and protein homocysteinylation. Further, this review is dealing with the 'reverse epidemiology' issue, outlining also the main Hcy-lowering strategies.

Minor segmental wall motion abnormalities detected in patients with Chagas' disease have adverse prognostic implications.

Recent data from our laboratory have shown that patients with the indeterminate form of Chagas' disease can have impairment of left ventricular contractility, as evaluated by the slope of the left ventricle end-systolic pressure-dimension relationship. We also showed that Chagas' disease patients with minimal baseline wall motion abnormalities detected by two-dimensional echocardiography have more intense contractility impairment when compared to patients with the indeterminate form of the disease without this abnormality. The prognostic implications of these findings have not been established. We evaluated 59 patients (37-76 years, mean = 55 years) with different clinical forms of Chagas' disease, who had normal left ventricular global systolic function at baseline (57.6 +/- 6.9%) and who had at least one additional echo during clinical follow-up (0.4-17.6; mean 4.6 years). Group 1 consisted of 14 patients with minor baseline left ventricle wall motion abnormalities and group 2 consisted of 45 patients without these abnormalities. During follow-up, global left ventricle systolic function deterioration was observed in 10 group 1 patients (71.4%) and in only 10 group 2 patients (22.2%; P < 0.005). Age and duration of follow-up were not independent determinants of left ventricular function deterioration in these patients. The present data indicate that mild segmental left ventricular wall motion abnormalities are associated with worsening of systolic function in Chagas' disease patients who have normal baseline global systolic performance.

Minor segmental wall motion abnormalities detected in patients with Chagas' disease have adverse prognostic implications

Recent data from our laboratory have shown that patients with the indeterminate form of Chagas' disease can have impairment of left ventricular contractility, as evaluated by the slope of the left ventricle end-systolic pressure-dimension relationship. We also showed that Chagas' disease patients with minimal baseline wall motion abnormalities detected by two-dimensional echocardiography have more intense contractility impairment when compared to patients with the indeterminate form of the disease without this abnormality. The prognostic implications of these findings have not been established. We evaluated 59 patients (37-76 years, mean = 55 years) with different clinical forms of Chagas' disease, who had normal left ventricular global systolic function at baseline (57.6 ± 6.9 percent) and who had at least one additional echo during clinical follow-up (0.4-17.6; mean 4.6 years). Group 1 consisted of 14 patients with minor baseline left ventricle wall motion abnormalities and group 2 consisted of 45 patients without these abnormalities. During follow-up, global left ventricle systolic function deterioration was observed in 10 group 1 patients (71.4 percent) and in only 10 group 2 patients (22.2 percent; P < 0.005). Age and duration of follow-up were not independent determinants of left ventricular function deterioration in these patients. The present data indicate that mild segmental left ventricular wall motion abnormalities are associated with worsening of systolic function in Chagas' disease patients who have normal baseline global systolic performance.

Prophylactic placement of gastrostomy feeding tubes before radiotherapy in patients with head and neck cancer: is it worthwhile?

BACKGROUND: After radiation treatment of head and neck cancer, placement of gastrostomy feeding tubes can be technically difficult. The practice of placing tubes before treatment is probably justified if the tube is used for more than 4 weeks and if complications are infrequent. The aim of this study was to determine the outcome of prophylactically placed gastrostomy tubes in patients with head and neck cancer at our institution from 1995 to 1999. STUDY: Data collected retrospectively from the patients' medical records included demographics, duration of tube use, and complications associated with placement. RESULTS: A total of 54 patients (40 men, 14 women) with a mean age of 68.5 years (range, 49-88 years) were studied. Thirty-one patients were treated with both surgery and radiotherapy; 17, with only radiotherapy; and 6, with chemotherapy, radiation, and surgery. The gastrostomy tube was placed before initiation of radiation treatment in 41 patients and after treatment in 13. The method of placement included pull technique (n = 41), introducer technique (n = 10), and surgical (n = 3). Four patients who had a tube placed after treatment required hospitalization for dehydration, whereas no hospitalizations were needed in the prophylactic group. The median duration of tube use was 165 days (range, 0-1,105 days). Only three patients had a complication directly related to placement. CONCLUSION: Gastrostomy tube placement before treatment is appropriate, given the median number of days required for use and limited complications associated with placement.

Iontophoresis: an alternative in the treatment of dental caries?

This study deals with some aspects of caries decay etiology and treatment using iontophoresis, when there is no cavity, and discusses remineralization of decayed teeth.