Human marrow erythropoiesis in culture. I. Characterization of methylcellulose colony assay

We examined the morphological and functional characteristics of human marrow erythrocytes cultured with a recently developed methylcellulose colony assay technique. Erythrocytic cells in various stages of development were observed, and a significant degree of maturational synchrony within individual colonies was noted. By light microscopy, colonies consisting of late normoblasts appeared compact, had an orange hue attributable to their hemoglobin, and demonstrated pseudoperoxidase activity, whereas colonies composed of early erythroblasts grew less compact or in clusters of smaller cell aggregates and showed no reddish tinge. Colonies possessing intermediate features were also observed. Maturational synchrony of individual colonies was confirmed using ransmission and scanning electron microscopy. The ultrastructure and cytochemistry of most immature cells were normal. The mature erythrocytes, however, were severely microcytic and hypochromic and contained one to several Heinz bodies. These defects in the cytoplasmic maturation of erythrocytes corresponded with impaired granulocytic maturation in culture, which we observed previously, and suggest environmental or nutritional defects in culture. Linearity of the method was confirmed using five normal bone marrows. Erythropoietin dose-responses observed in ten normal marrows were comparable to the previously reported results and revealed significant variation in individual plating efficiencies.     

Significance of transient left ventricular wall thickening in acute lymphocytic myocarditis

Transient left ventricular (LV) wall thickening is observed in patients with acute lymphocytic myocarditis. The present study was undertaken to clarify the significance of transient LV wall thickening in patients with this disease. The subjects comprised 25 patients with acute lymphocytic myocarditis. Echocardiography was used to measure the thickness of the interventricular septum (IVS) and the LV posterior wall (PW) at four time points after myocarditis onset – namely, on days 1–3, 6–8, 13–15, and 28–30 – to clarify the timing and frequency of wall thickening. The 25 patients were divided into a fulminant myocarditis group (n = 14) and a nonfulminant myocarditis group (n = 11), and the relationship between LV wall thickening and myocarditis severity was investigated. Left ventricular wall thickening was greatest on days 1–3 after myocarditis onset (IVS: 13.3 ± 3.2 mm; PW: 12.1 ± 2.6 mm), with this finding being noted in 14 of the 25 cases (56%). By days 6–8, the thickness of IVS had virtually normalized to 10.6 ± 1.6 mm (P < 0.0001) and that of PW to 10.2 ± 1.4 mm (P = 0.0006). The thickness of the IVS and PW on days 1–3 after myocarditis onset were 14.6 ± 3.7 and 13.0 ± 2.9 mm, respectively, in the fulminant group (P = 0.014), and 11.5 ± 0.9 and 10.9 ± 1.4 mm, respectively, in the nonfulminant group (P = 0.039). In lymphocytic myocarditis, LV wall thickening is greatest on days 1–3 after myocarditis onset and improves to near normal by days 6–8. Such transient LV wall thickening occurs in approximately 50% of cases. Left ventricular wall thickening was more marked in the fulminant compared with the nonfulminant group.     

Effects of mixed polyethyleneglycol modification on fixed aqueous layer thickness and antitumor activity of doxorubicin containing liposome

Polyethyleneglycol (PEG) has often been used for the modification of liposomes, but it is difficult to insert PEG on the surface of liposomes, and the effects of modification are not marked enough. In this study, we examined the fixed aqueous layer thickness (FALT) of single or mixed PEG (molecular weight, 340, 500, 900, 2000)-modified doxorubicin (DOX) liposomes, and physical character and biological properties of these liposomes. On single PEG-modification, as the PEG-molecular weight increased, FALT also increased, but the ratio of the increase was reduced. While on modification by a mixture of PEG2000 and PEG with a short polyoxyethylene chain (PEG340 or PEG500), FALT increased compared with the single PEG2000-modified value. Moreover, when liposomes were modified by mixture of PEG2000 and PEG500, we recognized the most suitable mixed rate (PEG2000, 500=2:1), showed the maximum FALT. On the other hand, in vivo, as increase of FALT, DOX concentrations increased in the plasma and in the tumor, decreased in the liver. Furthermore, liposomes with remarkable increase of FALT showed enhancement of antitumor activity. As a result, the connection among increase of FALT and improvement of circulation in blood, the involvement of antitumor activity of DOX of these liposomes was suggested.     

Energy Expenditure and Caloric Balance After Burn: Increased Feeding Leads to Fat Rather Than Lean Mass Accretion

OBJECTIVE: Resting energy expenditure (REE) is commonly measured in critical illness to determine caloric "demands" and thus nutritive needs. SUMMARY BACKGROUND DATA: The purpose of this study was to 1) determine whether REE is associated with clinical outcomes and 2) determine whether an optimal caloric delivery rate based on REE exists to offset erosion of lean mass after burn. METHODS: From 1995 to 2001, REE was measured by indirect calorimetry in 250 survivors of 10 to 99%TBSA burns. Caloric intake and REE were correlated with muscle protein catabolism, length of stay, ventilator dependence, sepsis, and mortality. From 1998 to 2000, 42 patients (>60%TBSA burns) received continuous enteral nutrition at a spectrum of caloric balance between 1.0x REE kcal/d -1.8x REE kcal/d. Serial body composition was measured by dual energy x-ray absorptiometry. Lean mass, fat mass, morbidity, and mortality were determined. RESULTS: REE/predicted basal metabolic rate correlated directly with burn size, sepsis, ventilator dependence, and muscle protein catabolism (P <.05). Declining REE correlated with mortality (P <.05). 2) Erosion of lean body mass was not attenuated by increased caloric balance, however, fat mass increased with caloric supply (P <.05). CONCLUSION: In surviving burned patients, caloric delivery beyond 1.2 x REE results in increased fat mass without changes in lean body mass. Declining energy expenditure appears to be a harbinger of mortality in severely burned patients.     

Performance of the Carpentier-Edwards SAV and Hancock-II porcine bioprostheses in aortic valve replacement

BACKGROUND AND AIMS OF THE STUDY: Extended experiences of the Carpentier-Edwards Supra-Annular Valve (CE-SAV) and the Hancock II (H II) porcine bioprostheses were evaluated to determine the freedom from structural valve deterioration (SVD) by reoperation in the aortic position. METHODS: Between 1981 and 1994, 1,524 procedures (mean patient age 67.6+/-11.2 years) with the CE-SAV, and 670 procedures (mean patient age 65.2+/-12.1 years) with the H II were conducted at the University of British Columbia and University of Toronto, respectively. The patient populations were differentiated by mean age, gender and valve size, but not by concomitant coronary artery bypass. The analyses included actuarial and actual freedom from SVD and evaluation of predictors of SVD. RESULTS: Actuarial freedom from SVD at 15 years for patients aged > or =65 years was 91.5+/-2.9% for CE-SAV, and 100% for H II (p = NS), while the actual freedom was 96.4+/-1.0% and 100%, respectively. For the patient population aged 66-70 years, the actuarial freedom from SVD was 87.0+/-6.0% for CE-SAV and 100% for H II (p = NS), while the actual rates were 93.6+/-2.3% and 100%, respectively. For the population aged >70 years, the actuarial freedom from SVD was 96.9+/-1.5% for CE-SAV, and 100% for H II (p = NS), while the actual freedom was 98.8+/-0.5% and 100%, respectively. In the patient population aged <65 years, the actuarial freedom from SVD at 15 years favored the H II (p = 0.04), and the actual freedom showed the same outcome. The valve type was not predictive of SVD for age groups < or =60 years, >60 years, 61-70 years and >70 years, but was predictive for the overall population (p = 0.03), as was age and previous valve replacement. CONCLUSION: The CE-SAV and Hancock II both provide satisfactory clinical performances, with a low incidence of SVD, and no significant difference in SVD was shown in patients aged > or =65, 66-70, or >70 years. There is a trend to less SVD by actual analysis for the Hancock II in patients aged <65 years. This evaluation must be considered as work-in-progress because of the limited number of patients at risk at 15 years, especially with the Hancock II prosthesis.     

Metabolic effects of growth hormone treatment: an early predictor of growth response?

Fourteen children receiving one year of recombinant human growth hormone (rhGH) treatment underwent measurement of serial changes in body composition (measured by skinfold thickness, bioelectrical impedance, and H2(18)O dilution), resting energy expenditure (REE, estimated by ventilated hood indirect calorimetry), and total free living daily energy expenditure (TEE, measured by the doubly labelled water technique). Mean height velocity increased from 4.9 to 8.6 cm/year after six months of treatment. Fat free mass (FFM) increased more during the first six weeks (24.4 g/day) than from six to 26 weeks of treatment (6.8 g/day); fat mass decreased by 7.2 g/day and 1.1 g/day respectively. The six week increase in REE (kJ/day) was maintained after six months of treatment, though expressed per kilogram FFM (kJ/kgFFM/day), returned to pretreatment values by three months. Height velocity increases at six months correlated with six week changes in fat mass measured by skinfold thickness and REE, though use of this relationship to predict growth response in individuals is limited by the wide 95% prediction intervals. No significant changes in growth, body composition, or energy expenditure were observed between six and 12 months of treatment, in either patients who had initially responded well to treatment or those who were poor initial responders to treatment and who had their dose of rhGH doubled after six months.     

Determination of incorporated amounts of poly(ethylene glycol)-derivatized lipids in liposomes for the physicochemical characterization of stealth liposomes

We describe a method for determining incorporated amounts of poly(ethylene glycol) (PEG)-derivatized lipids in liposomes for the physicochemical characterization of PEG-coated liposomes. This method is based on the spectrophotometric determination of complexes of polyethers with sodium ions after their extraction as picrates into 1,2-dichloroethane, developed by Favretto for measuring levels of polyoxyethylene alkylphenyl-ether non-ionic surfactants in waste water. The same assay was applied to the estimation of PEG-derivatized lipids in liposomes and percent incorporation of PEG-derivatized lipids into liposomes was successfully determined. To prevent the interference from liposomal lipids other than PEG-derivatized lipids in this assay, liposomal samples were diluted at least to a concentration of less than 0.2 mM. The percent incorporation of PEG-lipids varied, depending on the molecular weight of PEG and anchor acyl chain length in PEG-lipids and it was suggested that the percent incorporation of PEG-lipids into liposomes would be a good parameter of quality control of PEG-liposomes in manufacturing facility and the picrate method used in the present study allows for the determination of this parameter without the need for hazardous radioisotopes.     

Neonatal stroke: Clinical characteristics and cerebral blood flow velocity measurements

The clinical courses of 8 term infants with focal cerebral infarction or neonatal stroke were studied to determine whether such infants can be identified by current markers of perinatal distress, and whether changes in cerebral blood flow velocity (CBFV) occur during the acute phase of the disease. CBFV was measured from the middle cerebral artery (MCA) and anterior cerebral artery (ACA) utilizing duplex Doppler. Seven of the 8 patients required no resuscitation in the delivery room; 1 infant required brief bag and mask ventilation. No infant had evidence of severe fetal acidemia (i.e., cord pH <7). All 8 infants were initially admitted to the newborn nursery. Infants were identified on the basis of abnormal clinical findings observed during the first 48 hours: seizures (n = 6) and hypotonia and apnea (n = 2). Serum electrolytes, calcium, magnesium, and glucose levels were normal, and the sepsis evaluation including a spinal tap was sterile in all patients. Neuroimaging revealed nonhemorrhagic left focal MCA infarction (n = 6) and right focal MCA infarction (n = 2). Duplex Doppler demonstrated transient ipsilateral decreases in CBFV as compared to the contralateral unaffected side at clinical presentation in 4 infants. In 2 of these infants the decrease in CBFV involved both the MCA and ACA, and in 2 infants, only the MCA vessels. These side-to-side differences were not present at subsequent CBFV measurements. The data indicate that infants who develop neonatal stroke cannot be distinguished from infants who do not develop the lesion by current markers of perinatal distress. Because neonatal stroke frequently occurs as an unanticipated event, prevention may not be possible.