摘要:

Thyroxine (T4) administration to adult female mice significantly increases submandibular gland (SMG) nerve growth factor (NGF) and epidermal growth factor (EGF) concentrations and does so in a time- and dose-dependent manner. Postnatal maturation of the SMG can be markedly accelerated by T4treatment. We, therefore, performed a series of experiments to examine the effect of T4on SMG NGF and EGF content and concentration as a function of postnatal age in neonatal mice. In experiment 1, male and female neonatal Swiss-Webster mice received daily subcutaneous injections of T4(0.4 µg/ g body weight) for 6,13, or 20 days and were sacrificed 24 h after the last injection. Vehicle injected mice served as controls. SMG NGF and EGF content and concentration were measured by specific double antibody radioimmunoassay systems. Pools were made using either female or male SMGs. Since no significant differences were noted for NGF or EGF content using sex of the animal as the determining variable, the values were combined. At 7 days of age, mean SMG NGF and EGF content and concentration of control mice significantly exceeded those of T4- treated animals (p<0.05). At 14 days of age, mean SMG NGF and EGF content in T4-treated mice significantly exceeded those in control mice by 39- and 22-fold, respectively (P< 0.001). At 21 days of age, these increases were 4100- and 2400-fold, respectively. In order to determine more precisely the time of onset of responsivity of the SMG to thyroid hormones, a second series of experiments was performed. Vehicle and T4(0.4 µg/g body weight daily) injected mice were sacrificed at 7, 9, 11, and 14 days of age. SMG EGF concentration was measured by radioimmunoassay. T4treatment was without significant effect at 7 and 9 days of age. At 11 days of age, mean SMG EGF content and concentration in the T4-treated mice exceeded that in control mice by a factor of 2 (p<0.05). Subsequently, SMG EGF content and concentration increased exponentially. Daily treatment of neonatal mice from birth or from the 7th postnatal day resulted in similar SMG EGF content and concentration when measured at 14 days of age. These data indicate that T4administration to neonatal mice significantly increases SMG NGF and EGF concentrations and markedly accelerates their appearance in the gland as early as 11 days of age. Onset of SMG EGF responsiveness to thyroid hormone appears to commence at some time on or after the 7th postnatal day. The observation of exponential increases in SMG growth factor concentrations strongly suggest thyroid hormone mediated synthesis. The use of the neonatal SMG as a model will allow further insights into the biosynthesis of NGF and EGF and also into the mechanism of thyroid hormone action.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

To learn more about the impact of intrathecal methotrexate and cystosine arabinoside therapy on neuronal metabolism, we measured serial cerebrospinal fluid concentrations of homovanillic acid and 5-hydroxyindoleacetic acid, major metabolites of the neurotransmitters dopamine and serotonin, in children with acute lymphocytic leukemia. Multiple sequential cerebrospinal fluids were obtained from 30 children with acute lymphocytic leukemia evaluated prospectively from the time of diagnosis. We focused on the period of induction and intensification when children received weekly intrathecal chemotherapy. Paired cerebrospinal fluid specimens were also obtained at 3- month intervals from 60 children with acute lymphocytic leukemia in remission. Homovanillic acid and 5-hydroxyindoleacetic acid were measured using high performance liquid chromotography with electrochemical detection. We found that pretreatment metabolite values were no different from those in age-matched subjects in remission. In the first 5 wk of treatment, there were no significant changes in metabolite levels in patients treated exclusively with methotrexate. There was a transient decrease in homovanillic acid (-28 ± 10%,p< 0.001, Student's t test) and 5- hydroxyindoleacetic acid (—28 ± 12%,p< 0.05) in five of six patients after a single intrathecal dose of cytosine arabinoside. In the next 4 wk there was a gradual rise in levels of homovanillic acid (p=0.001, by analysis of variance) and 5-hydroxyindoleacetic acid (p=0.029, analysis of variance); this pattern did not correlate with administration of cranial irradiation. In children in remission, there were no significant changes in metabolite levels over a 3-month period. The data suggest that intensive therapy including methotrexate and cytosine arabinoside alters central neurotransmitter metabolism and/or transport in children with acute lymphocytic leukemia.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

This report analyzes the effect on pulmonary vascular structure and function in the newborn guinea pig of chronic fetal hypoxemia, induced by maternal hypobaric hypoxia (380-420 torr) without direct interference with the utero-placental blood flow. Six pregnant guinea pigs were maintained in hypobaric chambers, 10 newborns from their litters being the hypoxic group. Twenty newborns from the litters of 10 pregnant guinea pigs maintained in air were the control group. After spontaneous delivery catheters were placed in the left carotid and the main pulmonary arteries of the newborns. Oxygen consumption was measured, pressures recorded from the pulmonary artery, right ventricle, and right atrium, oxygen saturation and hemoglobin concentration estimated on blood from systemic arteries, pulmonary artery, and right atrium, and cardiac output calculated (Fick principle). All data were normalized per kilogram body weight. Morphometric analysis of the pulmonary vasculature after injection of the pulmonary arteries showed no difference between the groups. Contrary to expectation chronic hypoxemia inuterodid not cause pulmonary hypertension or the precocious muscularization of the precapillary unit found in human cases of persistent pulmonary hypertension: it caused growth retardation, a feature not typical of the human syndrome.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Defects in polymorphonuclear neutrophil (PMN) adherence and chemotaxis in neonates are thought to be an important cause of their increased susceptibility to overwhelming bacterial infection. Few studies of these functions have been carried out in stressed neonates who are at even greater risk of infection. PMN adherence and chemotaxis were examined in 33 stressed neonates with acute lower respiratory illness, 13 healthy neonates, and 43 healthy adults using whole blood PMN adherence and chemotaxis assays. PMN chemotaxis was significantly decreased in stressed neonates (locomotion index of 38.4 ± 9.7 µm) compared with that of healthy neonates (48.9 ± 12.8 µm,p<0.01) or adults (61.6 ± 11.9 µm,p<0.001). PMN chemotaxis was studied during illness and recovery in 13 of the 33 stressed neonates and showed significant improvement during recovery (41.6 ± 9.9 and 53.2 ± 11.9 µm, respectively,p= 0.012). PMN adherence was decreased in stressed neonates (1.4 ± 1.6%) compared with that of adults (12.3 ± 11.4%,p<0.01) but was similar to that of healthy neonates (1.1 ± 1.4%). These findings suggest that further impairment of PMN chemotaxis in stressed neonates helps account for their increased susceptibility to overwhelming bacterial infection.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The relationship between heart rate variability and respiration patterns was investigated using spectral analysis techniques in nine full-term infants whose ages ranged from 39-75 h. All the infants were studied during sleep, although no attempt was made to classify rapid eye movement or nonrapid eye movement states prospectively. The data obtained were examined to determine which aspects of neonatal breathing patterns are correlated with heart rate variability. Three spectral regions of heart rate variability could be identified: a very low frequency region below 0.02 Hz; a low frequency region from 0.02-0.20 Hz; and a high frequency region above 0.20 Hz. The dominant heart rate variability activity in these neonates was seen in the very low and low frequency regions, with little activity in the high frequency regions. In contrast to older infants and adults, respiration and heart rate variability were not strongly related through a high frequency region respiratory sinus arrhythmia but rather through a breath amplitude sinus arrhythmia which occurs in the low frequency region of the spectrum. The prominent very low frequency activity and the low frequency activity ascribed to breath amplitude modulation may result from autonomic nervous system mediation of chemoregulation.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Food groups have been widely used in nutrition education but relatively few studies have employed food groups to interpret dietary intake. The 24-h dietary recalls of 534 male and 476 female adolescents, aged 10-19 yr, were analyzed using a food grouping scheme. Foods were grouped with emphasis placed on fats and carbohydrates. Frequency of use and contribution of food groups to the macronutrients were determined. When nutrient intake was analyzed as a percentage of total calories, both males and females were found to have similar profiles. More than 60% of each macronutrient was contributed by combinations of three major food groups. The meat/fish/poultry, milk/cheese/yogurt, and bread/cereal products food groups contributed 81.2% of the protein; milk/cheese/yogurt, bread/cereal products and sweets accounted for 63.0% of the carbohydrate intake; and 74.3% of the dietary fat consumption was attributable to the meat/fish/poultry, milk/cheese/yogurt, and fats food groups. There were no notable differences in the food groups used by males and females. However, differences between the sexes emerged when nutrient intakes as a percentage of calories were stratified and food group usage was investigated. Food groups associated with macronutrients that are believed to affect health status have been identified.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

The feasibility of using a multiple gas rebreathing technique to evaluate cardiopulmonary function in the ventilated neonate was assessed by measuring functional residual capacity, diffusing capacity of lung for carbon monoxide, and effective pulmonary capillary blood flow in 10 neonates with respiratory distress syndrome. Measurements were first made on the level of positive end expiratory pressure (PEEP) selected by the clinicians caring for the infants (“clinical” PEEP, mean of 4.4 ± 0.3 cm H2O). To evaluate the effect of PEEP on cardiopulmonary function, PEEP was then changed above (mean of 6.7 ± 0.4 cm H2O) and below (mean of 1.9 ± 0.3 cm H2O) this level and measurements were repeated. Mean functional residual capacity on clinical PEEP (10.8 ± 1.6 ml/kg) was far below the predicted normal and varied directly with changes in PEEP (mean change of 1.2 ml/kg/cm H2O). Diffusing capacity of the lung for carbon monoxide on clinical PEEP was 0.04 ± 0.01 ml/min/mm Hg/kg and did not change significantly with changes in PEEP. Mean effective pulmonary capillary blood flow was highest (70 ml/min/kg) at the lowest level of PEEP. However, the effect of increasing PEEP on effective pulmonary capillary blood flow in individual infants varied. Increasing PEEP increased arterial oxygen tension but did not cause changes in systemic arterial pressure or heart rate. We conclude that infants with respiratory distress syndrome have severe lung injury with decreased functional residual capacity and diffusing capacity of the lung for carbon monoxide, and that lung volume improves with the use of PEEP. Although PEEP has a beneficial effect on arterial oxygenation, it may impair systemic oxygen transport in some infants because of its detrimental effect on cardiac output. This detrimental effect on cardiac output could not be detected by usual clinical monitoring techniques.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

We have previously shown a significant increase in35sulfate uptake in rat glomerular basement membrane (GBM) when glomeruli were cocultured with peripheral blood mononuclear cells (PBMC) from patients with idiopathic minimal lesion nephrotic syndrome (IMLNS) in relapse, but an uptake not different than normal controls if glomeruli were incubated with PBMC of patients in remission. In the present study we examined35sulfate uptake by GBM after PBMC from 12 IMLNS patients in remission were stimulated with Concanavalin A (Con A) (10 µg/ml of culture media). There was a significant increase in35sulfate GBM uptake when glomeruli were cocultured with Con A-stimulated IMLNS PBMC (geometric mean), 331 cpm/mg dry glomerular weight) as compared to glomeruli cocultured with IMLNS PBMC (geometric mean, 200) (p=0.048); glomeruli alone stimulated with Con A (geometric mean, 182) (p=0.008) or glomeruli alone (geometric mean, 146) (p=0.002). No significant differences were seen between the groups when glomeruli were cocultured with PBMC from 12 normal adults. These data show that Con A stimulated PBMC from IMLNS patients in remission alter the sulfate metabolism of rat GBM. The stimulation of PBMC with Con A reproduces the increase in35sulfate uptake observed when glomeruli are cocultured with PBMC from IMLNS in relapse. Sulfated compounds in the GBM may play a role in glomerular permeability. Since stimulated nephrotic PBMC alter the metabolism of GBM sulfated compounds, these findings may have pathogenic significance.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

In this study the lipid and apoprotein profiles were investigated in newborns at 0, 7, and 30 days of life. The plasma lipoproteins were separated both by ultracentrifugation and gel filtration in order to compare the patterns obtained by the two techniques. At birth, the apo E concentration is comparable to that measured in adults, but its distribution among lipoproteins is significantly different as more than 80% of the plasma apo E belongs to high-density lipoproteins (HDL). At 7 and 30 days the plasma apo E concentrations are close to the values at birth, but a significant redistribution occurs from HDL to very low-density lipoproteins. By analogy with apo B, the plasma apo CIII concentration is low at birth and increases between 0 and 7 days by a factor of about two. Plasma triglycerides increase significantly during the first week of life so that the apo CIII increase is most pronounced in very low-density lipoproteins. These lipoproteins therefore become enriched in apo E, apo CIII and triglycerides between 0 and 7 days. At birth, a distinct HDL fraction, enriched in apo E, apo All and cholesterol (HDLE), could be detected. To compensate for the low LDL levels, this HDLEfraction might function as an additional source for cholesterol delivery to peripheral tissues via the apo (B, E) receptor. At later age, low-density lipoprotein synthesis is enhanced, apo E is transferred to very low-density lipoproteins, and cholesterol delivery via the HDLEbecomes less important. These data demonstrate that significant differences occur in the plasma concentration and distribution of the apo CIII and E proteins during the initial period of life, and that these apoproteins fulfill an important metabolic role.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID

摘要:

Patients with leprechaunism have hyperinsulinemia and extreme insulin resistance. The mechanism of the insulin resistance has not been delineated. To examine postreceptor events in this unusual syndrome we have assayed the enzyme guanylate cyclase [E.C.4.6.12], which is modulated by insulin, and the concentration of the intracellular messenger cyclic GMP in liver from two children with leprechaunism and extreme insulin resistance. Both patients exhibited down regulation of the red blood cell insulin receptors, but normal insulin receptor binding to Ebstein-Barr transformed IM-9 lymphocytes and monocytes. There was no evidence of antireceptor or antiinsulin antibodies. Activity of liver guanylate cyclase expressed as pmol/mg protein/10 min incubation in the soluble and paniculate fractions were, respectively, Ark-1 133 ± 18, 25 ± 6; Ark-2 129 ± 17, 23 ± 8; control children (six average) 287 ± 16, 55 ± 9. The concentration of cyclic GMP was also 50% lower (0.08 ± 0.03 in Ark-1 and 0.07 ± 0.04 in Ark-2), compared to 0.19 ± 0.07 pmol/mg protein/min in the control livers. There was no change in adenylate cyclase activity in children with leprechaunism versus the control children. These data suggest an abnormality of a postreceptor event in this rare genetic disease. These data, however, do not rule out that in some cases of leprechaunism a receptor binding abnormality may be the primary defect. We speculate that a defect in insulin action distal to plasma membrane receptor binding may be etiological in this unusual syndrome.

ISSN:0031-3998    

出版商:OVID    

年代:1986

数据来源: OVID