The diffusion of information technology among health maintenance organizations

This article examines the information technology functions, staffing and cost, services provided, and advanced technologies among health maintenance organizations (HMOs) using a national sample of HMOs from mid-1995. HMOs have a well-developed capability to use data from administrative functions, such as claims processing. Nationally affiliated HMOs and HMOs in markets with greater HMO penetration support more IT functions. Relatively little work has been completed integrating clinical with administrative systems.     

Accuracy and precision of peripheral quantitative computed tomography measurements at the tibial metaphysis.

The ability of 29 peripheral quantitative computed tomography (pQCT) software analysis modes at defining cortical from trabecular bone at three tibial metaphyseal regions was evaluated using five cadaveric tibiae. The accuracy of pQCT was determined by comparing the bone mineral content (BMC) with the ash weight. The precision of the pQCT scanner was calculated using repeated measurements. All the analysis modes had a good accuracy when measuring total bone area and a poor accuracy when measuring cortical bone area at the proximal 5% and distal 4% regions. For trabecular bone measured at all three regions and cortical bone area measured at the proximal 10% region, the Stratec peel mode 5 was the most accurate analysis mode. Highly significant correlations (r = 0.71-0.98) and a moderate accuracy error (coefficient of variation [CV] = 5-22%) was found between ash weight and BMC when using this mode. The precision of bone mineral density (BMD) measurements was good (total, CV = 2-5%; trabecular, CV = 2-5%; cortical, CV = 4-6%). pQCT is a moderately accurate, precise method of measuring trabecular and total BMD at the tibial metaphysis. The authors recommend caution when interpreting results for cortical BMD, as cortical area measurements at the metaphyseal region are less accurate and less precise.     

Treatment of imipramine-resistant recurrent depression, III: Efficacy of monoamine oxidase inhibitors.

BACKGROUND: The effectiveness of monoamine oxidase inhibitors (MAOIs) in tricyclic resistant depression has received surprisingly little systematic study. METHOD: Patients who failed to respond to sustained, adequate treatment with the tricyclic imipramine (mean maximum dosage = 260 mg/day) and interpersonal psychotherapy were withdrawn from imipramine and treated in a standardized, but open-label 6-week trial with either phenelzine (N = 4; 60 mg/day) or tranylcypromine (N = 36; mean = 38.5 mg/day) and continued interpersonal psychotherapy. RESULTS: Forty of 42 patients (95%) completed the trial, of whom 23 (58%) responded to treatment. Highly significant improvement was documented on measures of depression, reversed neurovegetative symptoms, and somatic symptoms. Response was significantly correlated with severity of depression (pre-MAOI score on the Hamilton Rating Scale for Depression), severity of a composite score of anergic and reversed neurovegetative features, and low levels of improvement during initial imipramine/interpersonal psychotherapy. Of patients who met criteria for proposed subforms of anergic or atypical depression, 67% (18/27) responded (p less than .05); 77% (17/22) of patients who scored above the mean on the composite measure of anergic and reversed neurovegetative features responded (p less than .01). CONCLUSION: These findings provide strong evidence of the utility of MAOIs in tricyclic-resistant depression, especially in patients with features such as fatigue, volitional inhibition, motoric retardation, hypersomnia, and/or weight gain.     

Factors related to the induction of ventricular fibrillation in the normal canine heart by programmed electrical stimulation

Programmed electrical stimulation was performed in eight normal dogs using a stimulator and endocardial electrode catheters identical to those used in human studies. The right and left ventricular apex were paced at a drive cycle length of 400 ms and, in some cases, 500 ms, with a pacing sequence of single (S1S2), double (S1S2S3) and triple (S1S2S3S4) premature impulses introduced after eight paced complexes. Pacing sequences were performed using combinations of pulse width (1, 2 and 4 ms) and current strengths of 2, 5 and 10 times diastolic threshold, and in three dogs, 15 times diastolic threshold. Twenty-two episodes of ventricular fibrillation were initiated in five dogs in 170 pacing sequences using current strengths up to 10 times diastolic threshold, and six episodes of ventricular fibrillation in the two of three remaining dogs tested at 15 times diastolic threshold. Ventricular fibrillation was reproducible on seven of nine occasions. Ventricular fibrillation was never induced by S1S2 at up to 15 times diastolic threshold; it was induced by S1S2S3 in 3 (1.8%) of 170 sequences, but only at 10 times diastolic threshold. It was induced by S1S2S3S4 in 19 (11.4%) of 167 sequences using 2 to 10 times diastolic threshold, although 20 of 28 episodes only occurred with S1S2S3S4 at 10 or more times diastolic threshold.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cerebral blood flow and cerebral metabolism in acute increase of intracranial pressure

Summary The effects of a stepwise acute increase of intracranial cerebrospinal fluid pressure on cerebral blood flow, cerebral arteriovenous differences of oxygen and glucose and on the output of lactate were studied in anaesthetized normoventilated normoxic dogs. Intracranial hypertension was produced by infusing mock-CSF into the cisterna magna. Mean arterial blood pressure was kept at a constant level throughout the experimental investigations. At a cerebral perfusion pressure of about 70 mm Hg, CBF and the cerebral metabolic rates of oxygen and glucose were not significantly changed. However, further reduction in the cerebral perfusion pressure to below 40 mm Hg, was accompanied by a statistically significant decrease of CBF and a deterioration of the oxidative metabolism. Glucose uptake was particularly disturbed by raised intracranial pressure. Increased cerebral output of lactate and low CMRO₂ indicated raised glycolysis. But (V-A)lactate was also increased at a relatively moderate reduction of the cerebral perfusion pressure, when autoregulation was still effective and CMRO₂ unchanged. The data are discussed in context with similar experimental results recently published by other investigators.Herrn Prof. Dr. H. Penzholz zum 60. Geburtstag gewidmet.     

Plasma zinc concentrations are depressed during the acute phase response in children with falciparum malaria

Plasma concentrations of some micronutrients are altered in the setting of acute infectious or inflammatory stress. Previous studies have provided conflicting evidence concerning the extent and direction of changes in plasma zinc concentrations during the acute phase response. We carried out an observational cohort study in 689 children enrolled in a randomized trial of zinc supplementation during acute falciparum malaria in order to evaluate the relation between plasma zinc concentration and the acute phase response. Plasma zinc was measured by atomic absorption spectrophotometry. On admission, 70% of all subjects had low plasma zinc (<9.2 micromol/L). Multivariate analysis of predictors of admission plasma zinc showed that admission C-reactive protein (CRP), parasite density, and study site were the most important predictors. Predictors of changes in plasma zinc from admission to 72 h included baseline CRP, change in CRP, treatment group, study site, and baseline zinc concentration. In children with acute malaria infection, baseline plasma zinc concentrations were very low and were inversely correlated with CRP (r = -0.24, P < 0.0001) and the degree of parasitemia (r = -0.19, P < 0.0001). Even when CRP and time were taken into account, zinc supplementation increased plasma zinc concentration from admission to 72 h. When available, plasma zinc concentrations should be interpreted with concurrent measures of the acute phase response such as CRP. In children whose age, diet, and/or nutritional status place them at risk of zinc deficiency, those with low plasma zinc levels should be supplemented with oral zinc and followed for clinical and/or biochemical response.