Perinatal management of ventral wall defects

Reported is the analysis of morbidity, mortality, and mode of delivery in 38 cases of ventral wall defects identified from among 128,500 consecutive live births in Maine (January 1975 to December 1982). Thirteen of the ventral wall defects were classified as gastroschisis, and only one had an additional defect not directly attributable to the ventral wall defect itself. By contrast, 16 of the 25 omphalocele cases had additional defects, including eight congenital heart lesions, four genitourinary malformations, two neural tube defects, and three trisomies. Ten cases of omphalocele and one of gastroschisis died, all as a result of independent defects or involvement of adjacent structures. Intrauterine growth retardation was prominently associated with gastroschisis. Vaginal delivery occurred in three of the six ventral wall defects diagnosed antenatally and in 28 of the 32 ventral wall defects not diagnosed until delivery. The only episode of birth trauma to ventral wall defect sac or abdominal viscera occurred during cesarean section in an undiagnosed case. The present data provide a basis for prognosis and management of antenatally diagnosed ventral wall defects and suggest that these defects are not, a priori, an indication for abdominal delivery.     

Stent graft repair of visceral artery aneurysms

PURPOSE: The purpose of this study was to compare the efficacy of rifampin-bonded gelatin-sealed and silver acetate/collagen-coated knitted polyester prostheses for the prevention of bacteremic graft infection in an animal model. METHODS: Eighteen 6.0-mm polyester grafts (length, 5.0 cm) were implanted in dogs end-to-end into the infrarenal aorta. The dogs were divided into four groups as a function of type of prosthesis implanted. The dogs in groups I (n = 3) and II (n = 3) received control gelatin-sealed or collagen-coated polyester prostheses, respectively. In group III (n = 6), the dogs received rifampin-bonded gelatin-sealed polyester prostheses. In group IV (n = 6), the dogs received silver/collagen-coated polyester prostheses. Two days after implantation, the grafts were challenged with 6 x 10(9) Staphylococcus aureus intravenously. One week after implantation, the grafts were harvested with sterile technique. Quantitative cultures were obtained from all the harvested grafts. The results were expressed as colony-forming units per cm(2) of graft material. Bacteriologic study was also performed on various tissue samples. The chi(2) test was used to compare the culture proven infection of control and antimicrobial grafts. RESULTS: All the control grafts were infected with S aureus at the time of removal. Five of the six silver/collagen-coated grafts were infected, whereas none of the six rifampin-bonded gelatin-sealed grafts grew S aureus (P <.01). There was no significant difference in the number of positive culture results of organ samples between the different groups of dogs. CONCLUSION: These results indicate that rifampin-bonded gelatin-sealed polyester grafts are significantly more resistant to bacteremic infection than are silver/collagen-coated polyester grafts in a highly challenging model.     

Elevation of arterial potassium during acute systemic hypoxia is abolished by alkalosis

BACKGROUND: Small elevations in plasma potassium evoke vasodilation in the peripheral circulation. Systemic hypoxia elevates arterial potassium and also modifies arterial pH. AIMS: We examined the interaction between pH and potassium in blood during systemic hypoxia and the effect of pH on the uptake/release of potassium in the peripheral tissues. METHODS: Anesthetized dogs were ventilated with air plus oxygen for normoxia or air plus nitrogen for hypoxia. Some animals received intravenous sodium bicarbonate to elevate pH by 0.1 units. Arterial plasma potassium concentration was measured in normoxia and hypoxia. A rat gracilis muscle was perfused with normoxic Krebs buffer and the potassium content of the venous outflow was compared during perfusion at pH 7.4, 6.8, or 7.8. RESULTS: In dogs with an arterial pH of 7.40-7.45, systemic hypoxia elevated the arterial potassium by 1 mmol/L. An arterial pH of 7.55 did not alter the basal potassium concentration, but it abolished the hypoxia-induced increase. In rat muscle, reduction of the perfusate pH from 7.4 to 6.8 reduced arterial perfusion pressure from 8.73 to 7.32 kPa and venous potassium from 6.6 to 5.2 mM. Elevation of perfusate pH to 7.8 decreased the arterial perfusion pressure from 8.44 to 6.95 kPa but did not affect venous potassium. CONCLUSIONS: The hypoxia-induced elevation of arterial potassium is abolished by increasing the pH to 7.55. This is not due to enhanced potassium uptake into peripheral tissues at high pH. Red blood cells are suggested as the most likely source of the potassium released in hypoxia.     

Postnatal stress of early weaning exacerbates behavioral outcome in prenatal alcohol-exposed juvenile rats

Some of the behavioral deficits caused by prenatal or postnatal alcohol exposure have been demonstrated to be ameliorated by environmental manipulations such as handling or environmental enrichment. This experiment, in contrast, investigated whether behavioral deficits due to prenatal alcohol exposure could be exacerbated by a stressful experience, early weaning. Pregnant dams were given either a liquid diet with 35% of the calories derived from alcohol, a liquid diet without alcohol to control for any effects of the liquid diet administration, or ad libitum food and water. Half of each litter were weaned at 15 days of age (early weaning) and half were weaned at 21 days of age (normally weaned). Offspring were weighed, tested for activity in an open field at 18 days of age, and trained to find a hidden platform in the Morris water maze at 22-24 days of age. Alcohol-exposed subjects who were weaned early were more impaired in spatial navigation ability than any other group. Similarly, the combination of early weaning and prenatal alcohol exposure caused the slowest growth. All subjects exposed to alcohol, regardless of weaning condition, had greater latencies to find the platform than those from the two control groups. There was no synergistic effect of alcohol and stress on activity levels, but all early-weaned females were more active than normally weaned females; males did not show this effect. Thus, environmental stressors such as early weaning can compound detrimental symptoms of prenatal alcohol exposure. These results have implications for the understanding of the effects of the environment on neuronal plasticity.     

Pharmacokinetics and electrocardiographic pharmacodynamics of artemether-lumefantrine (Riamet) with concomitant administration of ketoconazole in healthy subjects

AIMS: To evaluate whether the potent CYP3A4 inhibitor ketoconazole has any influence on the pharmacokinetic and electrocardiographic parameters of the antimalarial co-artemether (artemether-lumefantrine) in healthy subjects. METHODS: Sixteen subjects were randomized in an open-label, two period crossover design study. Subjects received a single dose of co-artemether (day 1) either alone or in combination with multiple oral doses of ketoconazole (400 mg on day 1 followed by 200 mg o.d. for 4 additional days). Serial blood samples were taken and assayed for artemether and its main active metabolite dihydroartemisinin (DHA), and lumefantrine. RESULTS: The pharmacokinetics of artemether, its metabolite DHA, and lumefantrine were influenced by the presence of ketoconazole. AUC(0, infinity ) was increased from 320 to 740 ng ml-1 h (ratio 2.4, 90% CI 2.00, 2.86) for artemether, from 331 to 501 ng ml-1 h (ratio 1.7, 90% CI 1.40, 1.98) for DHA, and from 207 to 333 micro g ml-1 h (ratio 1.7, 90% CI 1.23, 2.21) for lumefantrine in the presence of ketoconazole. Cmax also increased in similar proportions for the three compounds (ratio 2.2 (90% CI 1.78, 2.83), 1.4 (90% CI 1.12, 1.74), and 1.3 (90% CI 0.96, 1.64), respectively). The terminal elimination half-life was increased for artemether (2.5 vs 1.9 h, 90% CI 1.12, 1.72) and DHA (3.1 vs 2.1 h, 90% CI 0.02, 3.36), but remained unchanged for lumefantrine (88 vs 95 h, 90% CI 0.81, 1.04). These increases in exposure to the antimalarial combination were much smaller than observed with food intake (up to 16 fold), and were not associated with increased side-effects or changes in electrocardiographic parameters. The study medications were well tolerated. CONCLUSIONS: The concurrent administration of ketoconazole with co-artemether led to modest increases in artemether, DHA, and lumefantrine exposure in healthy subjects. Dose adjustment of co-artemether is probably unnecessary in falciparum malaria patients when administered in association with ketoconazole or other potent CYP3A4 inhibitors.     

RURAL URGENT CARE MODELS: WHAT ARE THEY MADE OF?

ABSTRACT: The study aimed to identify the elements that constitute rural urgent care systems. Participation in the study was sought from health professionals, welfare and emergency services sectors, and community members. Primary data were collected from informants through interviews and focus groups in five rural communities of different sizes. Twelve common elements to rural urgent care systems were identified and divided into two categories: (i) infrastructure; and (ii) personnel. Infrastructure included organisational support, community support, transport, communication and coordination processes, facilities and equipment, and community knowledge and information. Personnel included nurses, doctors, community leaders, health and welfare professionals, emergency service workers and ambulance officers. The study's major outcome was the recognition that rural urgent care systems consist of a balance of interrelated elements. These elements are context driven, with geographical, social and economic environments having a substantial impact on the ability of rural communities to develop and sustain their urgent care systems.     

Substitution in a Medicaid mental health carve-out: services and costs

The objective is to empirically test the incentives associated with a Medicaid capitated mental health carve-out contract, whether outpatient services (less expensive, inside the contract) and residential treatment center care (costly care, outside of the contract) were substituted for inpatient psychiatric hospitalization used by children and adolescents. Data sources include Medicaid fee-for-service (FFS) claims for the non-capitated comparison sites and for residential treatment center use, and "shadow billing" encounter data for the experimental capitated managed care sites that provided public mental health services for children and adolescents with Medicaid insurance statewide in Colorado from September 1994 to June 1997. Two part least squares regression models are used to decompose services. Managed care sites are compared to sites that remained under FFS financing, before and in two post-periods after the carve-out. Principal findings show that children and adolescents who received mental health services from a capitated managed care provider were significantly less likely to receive inpatient care, and significantly more likely to receive residential treatment center care. In addition, insurance contract design contains financial incentives that affect the amount and mix of clinical care provided to clients by risk-bearing provider agencies. Findings provide evidence of cost substitution from inpatient care both inside the specialty system and outside the carve-out to other child-serving systems.