The HemoCue®, a point of care B-hemoglobin photometer, measures hemoglobin concentrations accurately when mixedin vitro with canine plasma and three hemoglobin-based oxygen carriers (HBOC)

PURPOSE: Accuracy of measurement of low hemoglobin concentrations using the HemoCue, a B-hemoglobin photometer (HemoCue AB, Angelholm, Sweden) may exhibit significant variability. Infusion of hemoglobin-based oxygen carriers (HBOC) results in low concentrations of plasma hemoglobin. Our study assessed B-hemoglobin photometer measurement accuracy of three HBOC: (hemoglobin glutamer-200 (bovine; Oxyglobin, Biopure Corp., Cambridge, MA, USA); hemoglobin glutamer-250 (bovine; Hemopure, Biopure Corp, Cambridge, MA, USA), and hemoglobin-raffimer, (human; Hemolink, Hemosol, Inc., Toronto, Ontario, Canada). METHODS: In the laboratory, 45 split canine plasma samples were mixed with hemoglobin glutamer-200 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 samples were mixed with hemoglobin glutamer-250 (8.13, 16.25, 32.5 g x L(-1) concentrations), 45 with hemoglobin-raffimer (12.5, 25.0, 50.0 g x L(-1) concentrations), and measured. Plasma samples without HBOC served as control. Hemoglobin concentration was determined by a laboratory analyzer (Coulter Corporation, Hiafeah, FL, USA) and B-hemoglobin photometer (HemoCue, Angelholm, Sweden). Two independent technicians performed blinded sample measurements and randomly tested each sample five times. Results were analyzed according to Bland and Altman analysis. RESULTS: B-hemoglobin photometer demonstrated high repeatability for all three HBOCs. Repeatability coefficients were 0.37 g x L(-1) and 0.48 g x L(-1) for hemoglobin glutamer-200, 0.39 g x L(-1) and 0.4 g x L(-1) for hemoglobin glutamer-250 and 1.07 g x L(-1) and 0.85 g x L(-1) for hemoglobin-raffimer. An acceptable agreement was found between the B-hemoglobin photometer and the laboratory analyzer for all three HBOCs tested. CONCLUSION: The B-hemoglobin photometer accurately determined the concentration of three HBOC solutions dissolved in canine plasma.     

Analysis of lick rate measures the positive and negative feedback effects of carbohydrates on eating

Previous work has shown that measuring the rate of ingestion of liquid diets, rather than simply volume, reveals important features of ingestive behavior which can help to explain why a particular volume of a liquid is ingested. This study is an extension of that work to a variety of different test solutions. In this study the rate of ingestion of saccharin, two different concentrations of glucose and sucrose and their mixtures with saccharin and seven different concentrations of maltose were measured. The rate functions were fit by the least-squares method to a linear function to determine the intercepts and slope constants. Analysis of how these two parameters changed with the concentration and composition of the test solutions confirms, using different test solutions, a previously reported conclusion that the initial rate of ingestion (the intercept) measures palatability and that the slope constant is a measure of the rate of development of a negative feedback satiety signal.     

Effect of dietary restriction upon the age-associated decline of lymphocyte DNA repair activity in mice

Effects of dietary restriction (DR) on DNA repair capacity of mouse splenocytes after ultraviolet (UV)-induced damage were assessed. Two mouse cohorts received restricted amounts of purified hypocaloric diets; one was minimally restricted (∼75% of the caloric intake of mice fed a commercial diet ad libitum), the other was severely restricted (∼50% caloric restriction). An inverse correlation between age and DNA repair was present in the two cohorts; however, the regression lines of the two cohorts showed different slopes. DR appears to decelerate the age-associated decline of DNA repair capacity, and this delay might account in part for the improved immune function shown by old mice on DR.     

Characteristics of Hidden Status Among Users of Crack, Powder Cocaine, and Heroin in Central Harlem

This article analyzes hidden status among crack, powder cocaine, and heroin users and setters, in contrast to more accessible users/sellers. Several sampling strategies acquired 657 users (N=559) and sellers (N=98). Indicators of hidden status were those who (1) paid rent in full in the last 30 days, (2) used nonstreet drug procurement. (3) had legal jobs, and (4) earned $1,000 or more in legal income in the last 30 days. Nearly half had at least one indicator: approximately 16% of users/sellers had two to four indicators. In logistic regression analyses, those who had not panhandled in the last 30 days, those who had used powder cocaine in the last 30 days, and those never arrested were the most likely to have hidden status, whether the analysis predicted those having any indicators or those having two to four indicators. The four indicators begin to operationally define hidden status among users of cocaine and heroin.     

Activity-induced weakness in recessive myotonia congenita with a novel (696+1G>A) mutation.

OBJECTIVE: To investigate the cause of the transient weakness that occurs in recessive myotonia congenita (RMC) following sustained muscle contraction. METHODS: Nerve excitability studies were performed on a 35-year-old male with RMC due to a novel 696+1G>A CLCN1 mutation. The median nerve was stimulated at the wrist and compound muscle action potentials (CMAPs) were recorded from abductor pollicis brevis (APB). Stimulus-response behaviour using two stimulus durations, threshold electrotonus to 100-ms polarizing currents, a current threshold relationship and the recovery of excitability following supramaximal stimulation were recorded at rest. Excitability parameters were also recorded before and after maximal voluntary contraction (MVC) of APB against resistance for 60s. Results were compared to data obtained from 12 normal controls. RESULTS: Baseline axonal excitability parameters were all normal, indicating that axonal function was normal at the point of stimulation. Following one minute of MVC, excitability parameters demonstrated a significant increase in threshold when compared to controls (RMC 54.9%; controls 15.5+/-3.1%). In the RMC patient, this increase in threshold was associated with a 39% reduction in the amplitude of the maximal CMAP, which remained unaffected in controls. CONCLUSIONS: The reduction in maximal CMAP is likely to represent muscle activation failure due to depolarization block, with the increase in threshold possibly reflecting a compensatory attempt by motor axons to overcome prolonged contraction-induced changes in the muscle membrane. SIGNIFICANCE: The prolonged recovery of excitability following sustained muscle contraction is likely to be a contributing factor to symptoms of weakness and fatigue experienced by RMC patients.     

Retinal pigment epithelial change and partial lipodystrophy

Cuticular drusen and retinal pigment epithelial changes were found incidentally in a 27 year old Lebanese woman during assessment of partial lipodystrophy. Her vision was normal despite involvement of both maculae. The patient had hypocomplementaemia, but serum C3 nephritic factor was absent and renal function was normal. She had impaired glucose tolerance and a continuous infusion of glucose with model assessment (CIGMA) test revealed low normal tissue insulin sensitivity and high normal pancreatic beta cell function. Mild fasting hypertriglyceridaemia (2.0 mmol/l) may have been secondary to impaired insulin sensitivity. Endocrine function was otherwise normal apart from a completely absent growth hormone response to adequate hypoglycaemia. The simultaneous occurrence of partial lipodystrophy and retinal pigmentary epithelial and basement membrane changes appears to be a newly recognized syndrome.     

Computer-directed stereotactic biopsy of intrinsic brain stem lesions

Despite advances in the neuro-imaging of the brain stem, an accurate diagnosis of intrinsic lesions in this region requires tissue sampling and histological verification. We have performed a series of computer-directed stereotactic procedures in 12 patients with intrinsic brain stem lesions. A positive diagnosis was obtained in 11 cases and therapeutic intervention was possible in four. There was no operative mortality. Because of the importance of an accurate diagnosis in order to avoid inappropriate therapy, together with the relative safety of the technique, computer-directed stereotactic biopsy should be considered in all patients harbouring an intrinsic brain stem mass.