摘要:

SummaryStarting from children and adult skeletal muscle biopsy specimens (150 mg), we devised a scaled-down technique for isolation and cell-free translation of total cellular messenger RNAs in a reticulocyte-lysate system. Moreover, starting from 200 mg of human muscle, the technique allowed us to purify a neosynthesized protein, glycogen phosphorylase b (EC 2.4.1.1), using a specific immunoaffinity microchromatography procedure.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThe maturation of myocardial alpha adrenoceptors was investigated in dogs. Alpha adrenoceptors were characterized by radioligand binding using [3H]-WB4101. In neonatal cardiac membranes, the binding of the ligand was rapid, reversible, of high affinity, saturable and stereoselective. The competition studies with adrenergic agonists and antagonists were indicative of alpha adrenoceptors. In adult dog cardiac membranes, consistent specific binding of the ligand could not be demonstrated. These studies indicate that there is a decrease in alpha adrenergic receptor density of canine cardiac membranes during maturation.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummarySkeletal maturity, or “bone age,” is one of the several criteria used to determine developmental or physiologic age as opposed to chronologic age. The purpose of this study of skeletal maturation of children with sex chromosome abnormalities (45,X, 47,XXX, 47,XXY, X-chromosomal mosaics) and controls is 2c-fold: (1) to investigate if children with sex chromosome aneuploidy ascertained in an unbiased fashion differ in skeletal maturation from their siblings and other normal healthy children born in Denver, Colorado, and (2) to assess if the skeletal age standards currently in use (Greulich-Pyle; Tanner-Whitehouse) are applicable to Denver children when evaluating radiographs for skeletal maturation. Mean chronologic and skeletal age were measured. Mean differences between skeletal and chronologic age for all groups across all measures were calculated.The 45,X females constitute the only group studied with bone ages lower than expected (0.05 >P> 0.01; two-tailed test). We found no other significant differences in skeletal maturation between Denver children with sex chromosome abnormalities and their siblings or the control sample of Denver children.Although we found the Tanner-Whitehouse standards to be more applicable for use with this population, all the Denver groups investigated yielded consistently lower bone ages than expected published norms.This is the first documentation in a group of children with sex chromosome abnormalities, ascertained in an unbiased fashion, that, with the exception of those with a 45,X karyotype, bone age is not significantly different from that of the normal population.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryStrain differences in virulence for types la, II and III group B streptococci were assessed using an animal model of group B streptococcal disease. Human isolates of group B streptococci, which have been shown to have strain specific differences in opsonic requirements, were also found to exhibit differences in virulence within the same serotype. Serum, possessing opsonic and protective antibody against one strain, often did not have activity against other strains of the same serotype. Our results point to a direct correlation between strain resistance to opsonization and increased virulence within a given serotype.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThe aim of the present study was to obtain more information on oxygen consumption in relation to Na reabsorption in the immature kidney during hydropenia (HP) and isotonic volume expansion (VE) corresponding to 5% of the body weight. The study was performed in 24 male Sprague Dawley rats, which were divided into four groups containing six rats each: (1) 22− to 24-day-old rats during HP; (2) 22− to 24-day-old rats during VE; (3) 40− to 42-day-old rats during HP; and (4) 40− to 42-day-old rats during VE. Blood from the renal vein and from the artery was sampled for estimation of oxygen consumption. Glomerular filtration rate (GFR) was estimated by inulin clearance and renal plasma flow by renal extraction of inulin.Hemoglobin conentration and hematocrit are lower in younger rats than in older ones. VE induces a significant and equivalent fall in both age groups. During HP, renal blood flow (RBF) and GFR in relation to body weight are almost 50% lower in younger than in older rats (P< 0.001). During VE, RBF and GFR increase by almost 100% in younger rats (P< 0.001) and reach the same values as in older rats (P> 0.05). The RBF and GFR increased by about 15% in the older rats during the transition from HP and VE (P> 0.05). The amount of Na reabsorbed in 24-day-old HP rats was only 56% of the amount of Na reabsorbed in 40-day-old rats (P< 0.001). After VE, Na reabsorption increased more in 24-than in 40-day-old rats (by 52% and 12%, respectively). The fractional sodium excretion (CNa/Cin) was lower in the 24− than in the 40-day-old VE rats. Renal oxygen consumption (ROC) in the 24-day-old HP rats (including basal oxygen consumption of 1 μmole/g kidney weight) was 53% of the ROC in 40-day-old HP rats. During VE, ROC increased more in the 24-day-old rats (34%) (P< 0.01) than in the 40-day-old rats (4%) (P> 0.05).The renal Na/O2ratio was the same in the 24-day-old HP, the 40-day-old HP and the 40-day-old VE rats. The 24-day-old VE rats had a significantly higher Na/O2ratio than the other groups studied (P< 0.01).It is concluded that the energy demands of the immature kidney are related to the GFR and the amount of reabsorbed Na. If the GFR and the amount of reabsorbed Na increase, the oxygen consumption also increases. The amount of the increase, however, is less in the younger rats during VE than it would be if the renal Na/O2ratio was fixed.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryCircadian rhythms of plasma renin activity (PRA) and plasma aldosterone (PA) were studied in eight healthy children, 7 to 15 years old. Blood samples were obtained at 7:00 AM, 10:00 AM, 1: 00 PM, 4:00 PM, 5:00 PM, 8.00 PM, and midnight on day 1 and 4:00 AM and 7:00 AM on day 2. Children had normal activity during this test.Intra- and interindividual changes were noted in PRA in plasma taken in the upright position. Mean PRA values for samples taken in the upright position were maximal at 1:00 PM (7 ng/ml/hr) and minimal at 5:00 PM (4.1 ng/ml/hr). Mean PRA in the supine position was maximal at 4:00 AM on day 2 (5.6 ng/ml/hr), and its rise was statistically significant compared with the mean PRA at 7:00 AM on the same day (3.9 ng/ml/hr). Plasma aldosterone varied without any definite pattern. No correlation was found between PRA and PA and between PRA and PA and 24-hr urinary sodium excretion.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThe effects of ouabain infusion were tested in six lambs before and after depression of myocardial function by halothane anesthesia. Halothane reduced the left ventricular rate of pressure rise (dp/dt), stroke work, and stroke volume; the ratio of preejection period to left ventricular ejection time rose. Heart rate and systemic vascular resistance did not change. Before halothane, ouabain infusion did not alter the hemodynamic variables measured. After myocardial depression, ouabain infusion returned dp/dt, stroke work, stroke volume and the ratio of preejection period to left ventricular ejection time to control levels. Pacing studies showed a biphasic relationship between left ventricular dp/dt and heart rate. Maximal dp/dt occurred at a heart rate 42 beats/min higher than the resting rate.These studies suggest resting myocardial performance in the healthy, newborn lamb is at near maximal level.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryWe have identified seven adenine nucleosides in urines of untreated adenosine deaminase (ADA) deficient patients, four of which (adenosine, 2‘-deoxyadenosine, 1-methyladenosine and N6-methyladenosine) have been previously identified in urines of normals and/or ADA deficient patients. We confirm that ADA deficient patients excrete markedly increased amounts of 2’-deoxyadenosine (582 ± 363versusnormal of < 0.1 nmoles/mg creati-nine) and increased amounts of adenosine (29.4 ± 5.7versusnormal of 4.12 ± 1.0 nmoles/mg creatinine).We have found three other modified adenine nucleosides previously undetected in human urine. These three compounds are 2‘-O-methyladenosine, N6, 2’-O-dimethyladenosine and an as yet incompletely characterized modified adenine nucleoside, R-adenosine. Only ADA deficient patients excrete detectable amounts of 2‘-O-methyladenosine (2.1 ± 1.1versusnormal of < 0.1 nmoles/mg creatinine), whereas both normals and ADA deficient children excrete N6, 2’-O-dimethyladenosine and R-adenosine. However, ADA deficient patients do excrete increased amounts of R-adenosine (5.5 ± 1.0versusnormal of 1.4 ± 0.4 nmoles/mg creatinine).

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID

摘要:

SummaryThere is considerable evidence that homocystine has a direct damaging effect on vascular endothelium and other tissues. The demonstration of the existance of protein-bound homocyst(e)ine has strengthened this hypothesis. In an attempt to remove bound homocyst(e)ine, D-penicillamine was given to three patients with pyridoxine-nonresponsive homocystinuria. Before the clinical trial, it had been demonstrated that 0.1 μmole per ml concentration of D-penicillamine or cysteamine released approximately 50% of the homocyst(e)ine bound to plasma proteinsin vitro. Oral D-penicillamine effectively reduced both free and plasma protein-bound homocyst(e)ine in homocystinurics from the second day of treatment. The homocystine excreted in the urine was mainly in the form of homocysteine-penicillamine disulfide. No mixed disulfide was detectable in the plasma, indicating an extremely high renal clearance. These observations suggested that oral D-penicillamine removed a considerable quantity of the bound homocyst(e)ine accumulated in the tissue proteins.

ISSN:0031-3998    

出版商:OVID    

年代:1982

数据来源: OVID