High resolution sonographic determination of the normal dimensions of the intracranial extraaxial compartment in the newborn infant

Prominence of the extraaxial space occasionally is encountered in infants referred for ultrasonography to exclude hydrocephalus. The interpretation of this finding can be problematic. We examined the width of the extraaxial compartment in 82 normal newborn infants. Scanning technique was optimized for viewing the near field, and the extraaxial space was measured over the cerebral convexities. Correlation was made with demographic variables. Measurements varied from 0 to 3.3 mm (mean, 1.6 mm), with slight negative linear relationship to gestational age. We conclude that small amounts of extraaxial fluid, up to 3.3 mm in width on scans, are common and normal in newborn infants.     

Determinants of collateral development in a canine model with repeated coronary occlusion

It is now accepted that repetitive 2-min coronary occlusion can develop collateral vessels to the area perfused by the occluded coronary artery. However, which factors influence collateral development has yet to be fully elucidated. The goal of the present study was to identify the determinants of the rate of coronary collateral development in dogs undergoing repeated coronary occlusion. The study was conducted in 19 conscious dogs instrumented for measurements of a subendocardial segment length in the area perfused by the left circumflex coronary artery (LCCA), LCCA flow, and left ventricular pressure. An externally inflatable pneumatic occluder was placed around the LCCA. After the recovery from surgery, 2-min LCCA occlusions were conducted eight times daily. Following 141 +/- 61 (SD) LCCA occlusions (20 +/- 7 days), an LCCA occlusion produced no reduction in segment shortening and negligible reactive hyperemia. The total number of LCCA occlusions needed for adequate collateral development (the rate of collateralization) correlated well with the severity of myocardial ischemia during the first occlusion, which was determined mainly by the extent of postsurgical initial collateral circulation. On the other hand, the response to the ischemic stimulus in the later stage of collateral development was independent of the extent of development of the initial postsurgical collaterals. It is concluded that the overall rate of collateral development is slower in dogs with initially poorer collaterals; however, the response of each dog to the ischemic stimulus in the later stage of collateral development was similar among dogs regardless of the extent of the initial collaterals.     

The early phase of engraftment after murine blood cell transplantation is mediated by hematopoietic stem cells

Blood cells transplantation is largely replacing bone marrow transplantation because engraftment is more rapid. This accelerated engraftment is thought to be mediated by relatively mature committed hematopoietic progenitor cells. Herein, we have used a modified rhodamine (Rho) staining procedure to identify and purify Rho+/++ (dull/bright) and Rho- (negative) subpopulations of hematopoietic progenitor cells in murine cytokine-mobilized blood. The Rho+/++ cell population contained > 99% of committed progenitor cells with in vitro colony-forming ability. The Rho- cell population contained the majority of hematopoietic stem cells with in vivo marrow repopulating ability. The rate of hematopoietic reconstitution was identical in recipients of grafts containing only purified Rho- stem cells or purified Rho- stem cells in combination with large numbers of Rho+/++ committed progenitor cells. In contrast, transplantation of 3-fold more hematopoietic stem cells resulted in accelerated reconstitution, indicating that the reconstitution rate was determined by the absolute numbers of Rho- stem cells in the graft. In addition, we observed a 5- to 8-fold reduced frequency of the subset of hematopoietic stem cells with long-term repopulating ability in cytokine-mobilized blood in comparison to steady-state bone marrow. Our results indicate that hematopoietic stem cells and not committed progenitor cells mediate early hematopoietic reconstitution after blood cell transplantation and that relative to bone marrow, the frequency of stem cells with long-term repopulating ability is reduced in mobilized blood.     

Two different genes encode ferrochelatase in Arabidopsis: mapping, expression and subcellular targeting of the precursor proteins

Six adolescents, five males with prolactin-secreting pituitary macroadenomas and one female with idiopathic hyperprolactinaemia, are described. Their ages at presentation ranged from 13 years 7 months to 16 years 6 months. Presenting symptoms included headache, visual field defect, arrested growth and puberty. Only two cases had galactorrhoea. Every case had an elevated serum prolactin level. Three had surgery before the results of serum prolactin were to hand. Each patient was treated with bromocriptine. Bromocriptine suppressed serum prolactin level to normal in four cases, but in the girl with idiopathic hyperprolactinaemia, bromocriptine was not useful. In two boys, serum prolactin was not suppressed with bromocriptine therapy alone, and they were subsequently treated with cabergoline, surgery and irradiation. Nevertheless, in children and adolescents with prolactin-secreting pituitary adenoma, bromocriptine should be the first line of treatment.     

The role of the nurse manager in ambulatory care: results of a national survey

Increasing complexity in ambulatory care settings requires nurse managers who can function at higher levels. Little agreement currently exists regarding the role expectations and academic preparation needed for nurse managers in ambulatory care settings. The majority of surveyed ambulatory care nurse managers (40%) have an AD or diploma as their highest level of academic preparation, and have thus acquired the majority of their management skills in the practice setting. The authors express concern that there are pressures to employ non-nurses as managers in ambulatory health care settings and that ambulatory nurse managers are often seen as not needing advanced academic preparation. A wide variety of settings including university and community hospitals, outpatient departments, physician group practices and HMOs, currently employ nurse managers in their multidisciplinary ambulatory care sites. The majority of ambulatory care nurse managers describe their model of care as either the medical model or the functional model.     

Exercise responses in patients with IDDM

OBJECTIVE: The hemodynamic, respiratory, and metabolic responses to exercise were studied in IDDM patients and control subjects to detect diabetic cardiomyopathy. RESEARCH DESIGN AND METHODS: Eight subjects aged 25-40 years with diabetes of at least 10 years' duration were compared with eight control subjects aged 21-46 years. All subjects underwent a progressive incremental bicycle exercise test with measurement of gas exchange, blood glucose, lactate, fat metabolite, and catecholamine levels and two steady-state exercise tests with measurement of cardiac output by a CO2 rebreathing method. A new first-pass radionuclide method was used to measure cardiac ejection fractions (EFs) at rest, peak exercise, and steady-state exercise. RESULTS: The peak achieved oxygen consumption was similar in the diabetic and control subjects (29.9 [25.1-34.6] and 31.4 [26.9-35.9] ml.min-1.kg-1, respectively; mean [95% CI]). There were no significant differences in heart rate, double product, ventilation, respiratory exchange ratio, or ventilatory equivalents for oxygen and CO2 during the incremental test. Glucose levels were higher in the diabetic subjects, but there were no significant differences in levels of lactate, catecholamines, free fatty acids, glycerol, or beta-hydroxybutyrate. Left ventricular EF fell from rest to peak exercise within the diabetic group (66.0% [59.6-72.4] at rest; 53.6% [45.6-61.6] at peak; P < 0.05) but this did not differ significantly from the control group (58.7% [52.3-65.1] at rest; 60.3% [48.9-71.7] at peak). Right ventricular EFs were similar in each group, and there was no reduction in peak filling rate to suggest diastolic dysfunction. The cardiac output responses to exercise were also similar in the two groups. CONCLUSIONS: There is no evidence of impairment of the exercise response in subjects with long-standing diabetes, and the apparent fall in left ventricular EF at peak exercise could be related to hemodynamic adaptation.     

Muscle Rad expression and human metabolism: potential role of the novel Ras-related GTPase in energy expenditure and body composition

Ras associated with diabetes (Rad), a new ras-related GTPase, was recently identified by subtractive cloning as an mRNA in skeletal muscle that is overexpressed in NIDDM. To better understand its metabolic significance, we measured skeletal muscle Rad expression in well-characterized insulin sensitive (IS) and insulin resistant (IR) subjects with normal glucose tolerance and in untreated NIDDM patients. We found no differences in expression of Rad mRNA levels among IS, IR, and NIDDM groups using a ribonuclease protection assay (0.22 +/- 0.06, 0.13 +/- 0.01, and 0.16 +/- 0.02 relative units, respectively; NS) and no differences in Rad protein expression using a specific anti-peptide Rad antibody (1.05 +/- 0.18, 1.14 +/- 0.08, and 1.08 +/- 0.21 units/mg protein, respectively; NS). However, Rad protein levels were positively correlated with BMI (r = 0.43, P = 0.03) and percentage body fat (r = 0.55, P < 0.005), two independent measures of obesity, and negatively correlated with resting metabolic rate (r = 0.49, P = 0.01). In multiple regression analyses, percentage body fat and resting metabolic rate independently accounted for 30 and 10% of individual variability in muscle Rad protein expression. In conclusion, Rad expression in skeletal muscle is not altered as a function of insulin resistance or NIDDM in humans. However, these data, for the first time, implicate a role for Rad in regulating body composition and energy expenditure and provide a framework for studies designed to elucidate Rad's cellular functions.