Analysis of reticulocyte counts using various methods.

The precision and accuracy of manual reticulocyte counts using the Miller disc reticle, other ruled reticle and no reticle are compared with the reticulocyte results from the automated Hematrak 590 instrument. Two slides of each of 50 patient blood specimens were sent to the hematology laboratories of each of six participating hospitals. In addition to between-method comparison (precision), the manual method results using the three different counting techniques were each compared with the Hematrak results to determine if there were significant differences in reported results (accuracy). Statistical analysis revealed that the Miller disc method was the most precise and accurate manual method as compared with the Hematrak. Methods without a Miller disc reported significantly higher reticulocyte counts. Imprecision was also higher among non-Miller manual methods. By using the Miller disc, the accuracy and precision of manual methods may be increased to that of the automated Hematrak method.     

The Effect of Flurbiprofen on Steady-State Plasma Lithium Levels

Study Objective . To evaluate the effects of flurbiprofen therapy on the pharmacokinetics of lithium. Design . Placebo-controlled, single-blind, crossover study. Setting . University-affiliated hospital. Patients . Eleven healthy women with bipolar disorder. Interventions . The subjects received therapeutic doses of lithium administered as an immediate-release capsule every 12 hours. In addition, they received one placebo tablet every 12 hours during phase I and flurbiprofen 100 mg every 12 hours during phase II of the study. Measurements and Main Results . Steady-state pharmacokinetic parameters were measured for each phase. Lithium trough plasma concentration (C_min) and area under the curve were statistically significantly increased (p<0.05) when patients received flurbiprofen. Flurbiprofen also caused decreases in lithium clearance and 24-hour lithium urine excretion, although the changes did not reach statistical significance. Clinically significant increases in C_min appeared to be associated with a greater than 1000-μg/24 hour decrease in urinary excretion of prostaglandin E₂. Conclusion . Patients with clinically normal renal function may experience an increase in lithium levels with the initiation of flurbiprofen therapy.     

Benign intracranial hypertension and recombinant growth hormone therapy in Australia and New Zealand

Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml ^-1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml ^-1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-² week^-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.     

The risk of cytomegalovirus infection in seronegative transfusion recipients not receiving exogenous immunosuppression

We studied 637 transfusion recipients seronegative for cytomegalovirus (CMV) in the following categories: neonates; pregnant women; and patients experiencing trauma, burns, cardiovascular surgery (adult or pediatric), major surgery, or gastrointestinal hemorrhages. Cultures and serological tests were used to follow up subjects for evidence of CMV infection for a period of three months after their last transfusion. Six (0.9%) developed CMV infection. No significant differences in risk among patient categories were observed. Infected patients received a significantly larger mean number of units of cellular blood products (CBP; 50.0 +/- 38.9 vs. 6.2 +/- 8.5; P less than .001) and plasma (23.7 +/- 15.3 vs. 2.6 +/- 4.6, P less than .001) than did uninfected patients. This result represents a risk per unit of CBP transfused of 0.14%, or approximately 0.38% per unit of seropositive CBP transfused. We observed, however, that patients exposed to CBP from greater than 30 donors had a higher risk of acquiring CMV infection than would be predicted if infectious units were randomly distributed among all donors (P less than .01).     

Comparison of uterine activity induced by nipple stimulation and oxytocin

Intermittent nipple stimulation has been proposed as a substitute for exogenous oxytocin infusion in the performance of contraction stress tests. To compare the uterine activity produced by these two methods, we studied a group of 45 term pregnant women undergoing indicated inductions of labor. Twenty-five patients had nipple stimulation and 20 patients received oxytocin infusions according to a study protocol. The two groups were similar in all obstetric parameters. Pre- and posttest uterine activity was measured by internal tocodynamometry and quantified in Montevideo units. A significant increase in uterine activity occurred in both groups (P less than .01). Regular uterine activity (three contractions in ten minutes) was achieved more rapidly (P less than .005), but at a lower level (P less than .001) in the nipple stimulation group. Pre- and posttest tonus did not change significantly in either group. In the nipple stimulation group, five patients (20%) did not achieve adequate contraction patterns after 15 stimulation-rest cycles (a total of 110 minutes) and three subjects (12%) experienced uterine hyperstimulation. These observations suggest that exogenous oxytocin and intermittent nipple stimulation may not have equivalent effects on uterine contractility. Therefore, it may not be justified to substitute one technique for the other or to use the same criteria for interpretation of contraction stress tests produced by both techniques.     

Performance measures for evaluating services for people with a first episode of psychosis

Aim: The purpose of this project was to operationalize and apply a previously identified set of performance measures designed to evaluate services for those experiencing a first episode of a schizophrenia spectrum disorder. Methods: Operational definitions were developed for previously identified measures through an iterative process of discussions between clinical experts and health‐care evaluators. Data were collected from existing sources including corporate databases, clinical databases and chart review. Results: Definitions were developed for 44 measures covering seven of eight domains recommended for service level evaluation by the Canadian Institute for Health Information domains. Forty measures could be calculated. Conclusions: The measures represent a comprehensive set of performance measures suitable for the evaluation of services for people with a first‐episode psychosis. The measures could be used by other services in order to establish standards and norms for routine clinical practice.     

31P NMR of electrically stimulated rectus femoris muscle: an in vivo graded exercise model.

This study reports on the development of a model for studying skeletal muscle metabolism in humans using NMR spectroscopy. Graded exercise was simulated using electrical stimulation in 10 healthy, fit subjects (mean VO2max = 53 +/- 4 ml.kg-1.min-1). The effects of varying the stimulation parameters, namely, the stimulation frequency, the stimulation intensity, and the duty cycle, as well as the spectral interrogation volume, were compared using data acquired from the rectus femoris muscle. With stimulation, the inorganic phosphate to phosphocreatine concentration ratio ([P(i)]/[PCr]) and the intracellular pH both follow curvilinear relationships over the stimulation frequencies from 3 to 30 Hz, with the magnitude of the observed change related closely to stimulation intensity and duty cycle. Oxidative phosphorylation predominates at stimulation frequencies below 12 Hz, while anaerobic metabolism increases sharply above 12 Hz. Our findings show clearly the interdependence of the effects of the various stimulation parameters and emphasize the care that must be exercised in interpreting the physiological significance of the biochemical data obtained from electrical stimulation models used to study skeletal muscle metabolism.