Postmenopausal hormone replacement therapy and cardiovascular disease

Cardiovascular disease is the leading cause of mortality in postmenopausal women in developed countries. A possible cardioprotective role of hormone replacement therapy (HRT) is suggested by epidemiologic studies of HRT and reduced risk of coronary heart disease, as well as by randomized trials of HRT and lipid subfractions. Estrogen has beneficial effects on the lipid profile, raising high-density lipoprotein cholesterol levels and reducing low-density lipoprotein cholesterol levels each by approximately 10%. Other possible biologic mechanisms include beneficial effects on vascular function, oxidative status, endothelial-dependent vasodilation, intimal hyperplasia and insulin sensitivity. Estrogen's net effects on coagulation and fibrinolysis are less clear. Estrogen replacement therapy is associated with decreased atherosclerosis in several animal models. However, most of the available data on HRT derive from observational studies or small randomized trials assessing biologic intermediates rather than clinical events. Further research, including large-scale randomized clinical trials, are required to evaluate definitively the role of estrogen replacement therapy, especially given uncertainties about the effects of combined estrogen-progestin therapy and the balance of benefits and risk of this common intervention in postmenopausal women.     

Infection after pediatric heart transplantation: results of a multiinstitutional study. The Pediatric Heart Transplant Study Group

BACKGROUND: Detailed information regarding the spectrum and predictors of infection after heart transplantation in children is limited because of relatively small numbers of patients at any single institution. We therefore used combined data obtained from the Pediatric Heart Transplant Study Group to gain additional information regarding infectious complications in the pediatric population. METHODS: To determine the time-related risk of infection and death related to infection in a large pediatric patient population, we analyzed data related to 332 pediatric patients (undergoing heart transplantation between January 1, 1993, and December 31, 1994) from 22 institutions in the Pediatric Heart Transplant Study Group. RESULTS: Among the 332 total patients, 276 infections were identified in 136 patients. Of those patients with development of infection, a single infection episode was reported in 54% of patients, 21% had two infections, and 25% had three or more infections. Of the 276 infections, 164 (60%) were bacterial, 51 (18%) were due to cytomegalovirus, 35 (13%) were other viral (noncytomegalovirus) infections, 19 (7%) were fungal, and 7 (2%) were protozoal. Bacterial infections were more common in infants younger than 6 months of age at time of transplantation, comprising 73% of all infections as compared with 49% in patients older than 6 months of age. The incidence of bacterial infection peaked during the first month after transplantation, with the actuarial likelihood of a bacterial infection among all patients reaching 25% at 2 months. The most common sites of bacterial infection were blood and lung (74% of bacterial infections). Cytomegalovirus accounted for 59% of viral infections, with a peak hazard occurring at 2 months after transplantation. Among all infections, cytomegalovirus was less common in infants younger than 6 months of age (8% of all infections) than in older patients (25%). By multivariate analysis, risk factors for early infection included younger recipient age (p = 0.05), mechanical ventilation at time of transplantation (p = 0.0002), positive donor cytomegalovirus serologic study result with negative recipient result (p = 0.004), and longer donor ischemic time (p = 0.04). The overall mortality rate from infection was 5%, with an actuarial freedom from death related to infection of 92% at 1 year after transplantation. The mortality rate was high in patients with fungal infections (52%), yet was low for those with cytomegalovirus infection (6%). Infections accounted for 27% of the overall mortality rate in infants younger than 6 months of age, compared with 16% for older patients. CONCLUSIONS: Although most infections in pediatric heart transplant recipients are successfully treated, infection remains an important cause of posttransplantation morbidity and death, especially in infants. Bacterial infections predominate within the first month after transplantation, whereas the peak hazard for viral infections occurs approximately 2 months after transplantation. Cytomegalovirus infections are common in the pediatric transplant population, but death related to cytomegalovirus is low.     

ECAT ART - a continuously rotating PET camera: performance characteristics, initial clinical studies, and installation considerations in a nuclear medicine department

The past decade has been characterized by few advances regarding the pathophysiology and prevention but many changes in the clinical treatment of patients with preeclampsia. Specifically, recommendations have been made for home or day-care management of a select group of patients with mild gestational hypertension or preeclampsia. Moreover, three randomized clinical trials revealed that expectant management with close monitoring of maternal and fetal conditions is possible in a select group of patients with severe preeclampsia at less than 34 weeks' gestation. In addition, the efficacy of magnesium sulfate in the prevention and control of eclamptic convulsion has been validated in randomized controlled trials performed worldwide. In contrast, recent randomized trials failed to demonstrate any major benefit from the routine use of low-dose aspirin in pregnancy, whereas a recent meta-analysis found calcium supplementation during pregnancy to be effective in reducing the risk of hypertension.