摘要:

SummaryThe activation of the terminal complement components, C3–9, plays an important role in the host's defense against infection. In the present study, the ability of bacteria to activate the third component of complement (C3) in newborn serum was examined.A variety of bacteria were incubated in test sera at 37°C for 30 min and the percent of available C3 that was activated was measured. Using one strain ofEscherchia coli(#3), 32% (mean) of the available C3 was activated in sera from 18 newborns, as compared to 85% in sera from their mothers and 79% in sera from 13 normal adults (P<0.005). In contrast, using another strain ofE. coli(N70), the percent of C3 activated in newborn sera (83%) was the same as in sera from their mothers (81%) or in sera from normal adults (73%). The defective activation of C3 in newborn sera byE. coliwas not related to the presence of the K1 antigen. Newborn sera were also challenged with other bacterial species and the activation of C3 was deficient when tested with klebsiellae, but not with staphylococci or streptococci. The defect in newborn sera appeared to be due to a deficiency of a serum factor rather than to the presence of an inhibitor.SpeculationThe defective activation of C3–9 in newborn sera by some bacteria may be, in part, responsible for the neonate's increased susceptibility to infection.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryA pure culture of human fetal lung type II pneumonocytes has been developed and labeled HFLP. Cells were studied during the period of exponential growth that was observed to occur in this system from day 4 to day 8 after subculture. Correlations with exponential growth were highly significant (P< 0.001) in all groups studied. Growth was not greatly different at any of the different oxygen tensions (30, 55, 80, and 145 mm Hg) examined except that growth was slightly more rapid at a PO2of 145 mm Hg than at a PO2of 80 mm Hg (P<0.05). The uptake of3H-choline into DSPC at a PO2of 30 mm Hg was significantly less than at 55 mm Hg (P< 0.001) or 80 mm Hg (P< 0.001), whereas the uptake at 145 mm Hg was also significantly less than that at 55 mm Hg (P< 0.001) or 80 mm Hg (P< 0.001). Uptake at 55 and 90 mm Hg was not significantly different. The response to added cortisol (1 µM) also varied with the oxygen tension, with no effect at a PO2of 30 mm Hg while, at a PO2of 55 mm Hg the3H-choline uptake was significantly different on day 5 (P< 0.001), day 6 (P< 0.001) and day 7 (P< 0.01). Similarly, at a PO2of 80 mm Hg the difference was significant on day 5 (P< 0.05), day 6 (P< 0.01) and day 7 (P< 0.01). At a PO2of 145 mm Hg, the difference was just significant on day 7 (P< 0.05). In isolated HFLP cells, an oxidant challenge produced by increasing PO2from 30 to 55 mm Hg resulted in a 96% increase in3H-choline uptake in both the control group (P< 0.001) and the steroid-added group (P< 0.001). In the combined HFLP and fetal lung fibroblast culture there was a 275% increase over the uptake before oxidant challenge after 48 hr (control groupP< 0.001, steroid groupP< 0.001). In the experiment where HFLP cells were grown in the presence of 10% fibroblast-derived medium, the increase after 48 hr was 135% over values before the oxidant challenge (control groupP< 0.001). In this experiment, the steroid-added group had an increased response compared to the control group 48 hr after the oxidant challenge (P< 0.02).SpeculationIt was speculated that the type II pneumonocyte requires an unknown cofactor in order to respond to antenatal steroid treatment by increased production of surface active materials. It was further speculated that the change of PO2that occurs in pulmonary tissue after delivery acts as an important biologic stimulus to cause increased production of surface active materials, and that this mechanism can be favorably enhanced by pretreatment with steroids, and is mediated in part by soluble factor(s) derived from the fetal lung fibroblast.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryPyruvate carboxylase (E.C. 6.4.1.1) activity was determined in the circulating peripheral lymphocytes and cultured skin fibroblasts from the family of a patient with hepatic, cerebral, renal cortical, leukocyte, and fibroblast pyruvate carboxylase deficiency (PCPortlanddeficiency). Lymphocyte activities were: mother, 33–39%; father, 11–29%; brother, 82–103%; and sister, 38–48% of the lowest normal. Fibroblasts from the patient's mother and father had 42 and 34%, respectively, of the activity of the lowest normal. These data demonstrate that the disease is inherited in an autosomal recessive manner and that lymphocytes and fibroblasts can be used to detect carriers. Neither pyruvate carboxylase nor mitochondrial PEPCK activity in lymphocytes was increased by a 21-hr fast.SpeculationThe demonstration that carriers of pyruvate carboxylase deficiency can be detected with a venous blood sample may allow, with the use of extensive family studies, the assignment of this enzyme to a chromosomal linkage group.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryThe effect of 8 months of administration of moderate doses of 25-hydroxycholecalciferol (25 OH D3) on radiologic, biologic, and bone histologic changes was assessed in five children on chronic hemodialysis. Osteomalacia, defined by an increase in the thickness index of the osteoid seams and decrease of the calcification rate, was present on the initial bone biopsy of only one patient and improved with the treatment. Secondary hyperparathyroidism and its prints on bone tissue, noted in all five children, did not improve in the absence of adequate serum phosphorus control. Furthermore, cancellous bone volume diminished in two patients with the administration of 25 OH D3. This activity of the drug could be related to its inhibitory effect of osteoblastic apposition as demonstrated by the decrease in the calcification rates, while the thickness index of the osteoid seams remains normal.Despite the small number of patients studied, these results suggest the importance of limiting the prescription of 25 OH D3 to children suffering from renal osteodystrophy only after having assessed unequivocally an osteomalacic component by histodynamical criteria. Secondary hyperparathyroidism appears not to be improved with moderate doses of 25 OH D3 in the absence of adequate serum phosphorus control.SpeculationTreatment with 25 OH D3 may be justified for the treatment of chronic hemodialyzed children with definite osteomalacia as a component of their renal osteodystrophy. Secondary hyperparathyroidism appears not to be improved with moderate doses of 25 OH D3 in the absence of adequate serum phosphorus control.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummarySilent carrier α-thalassemia was identified in two individuals, one with sickle-cell trait and the other hemoglobin (Hb) C trait. Both are parents of a child with characteristic hematologic features of the Hb SC-7α thalassemia syndrome, including microcytosis and an unbalanced pattern of globin synthesis. In contrast to the typical findings that accompany heterozygous Hb S or Hb C with concomitant α-thalassemia trait, neither of the parents had microcytosis nor a percent of the abnormal hemoglobin in their erythrocytes that was below the normal range. In both, however, globin synthesis of peripheral blood reticulocytes was unbalanced, consistent with mild α-thalassemia. These findings suggest that the α-thalassemia silent carrier may be hematologically indistinguishable from the nonthalassemic individual, even when hemoglobin S or C are present.SpeculationThese findings provide additional evidence that the genetic pattern of α-thalassemia in American blacks is probably similar to that previously characterized in Far-Eastern populations, in spite of the clear differences in the clinical and hematologic expression of these disorders in the two populations.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryPositive end-expiratory pressure (PEEP), while of major benefit in the therapy of pulmonary diseases characterized by low functional residual capacity (FRC), is frequently associated with depression of cardiac output (CO) and specific dynamic compliance (Csp). The cardiopulmonary consequences of sequential increases of PEEP (3, 6, 9, 12, 15 cm H2O) in normal dogs were studied utilizing an apparatus that permits measurement of FRC by helium dilution while the animal remains on PEEP. It was found that increasing levels of PEEP had no effect on tidal volume (VT) or inspiratory time, but appeared to lengthen expiratory time by delaying expiratory flow until the preinspiratory period, and led to facilitated expiration. This response occurred immediately upon changes in the level of PEEP and is felt to be reflex in nature. FRC increased and Csp fell as PEEP was increased. This was reflected in a fall in transmission of applied airway pressure to an esophageal balloon. Pulmonary hypertension did not develop in our animals, but net right atrial (RA) pressure was elevated by PEEP. There was no difference in cardiac index (CI) between the control and study groups. Both the magnitude of applied airway pressure and the extent to which it is transmitted across the lungs to the pleural space appear to be determinants of possible effects of PEEP on CO and may explain the diversity of results among reported studies of PEEP. Transmission of pressure is related directly to Csp.SpeculationTransmission of PEEP to the pleural space is dependent on the level of PEEP and on the preexisting state of the lungs. Transmission of applied airway pressure will be greatest when the Csp of the lungs is highest; it may be reduced significantly if either insufficient or excessive levels are used for a given clinical situation. The pleural pressurevsapplied PEEP relationship thus provides a sensitive index of changing status of the lungs, as well as an assessment of therapeutic efficacy.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryMethylxanthines are shown in this study to decrease cholesterol synthesis in cultured C-6 glial cells. Aminophylline (10−3M) produced a rapid decline in cholesterol synthesis so that by 6 hr, synthesis in treated cells was less than 20% of that in untreated cells, and by 24 hr, less than 10%. Aminophylline induced parallel changes in 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase activity, the rate-limiting enzyme in cholesterol synthesis. Theophylline and caffeine produced similar effects. Thus, methyxanthines caused a specific, enzyme-mediated reduction in cholesterol synthesis in C-6 glia. In an attempt to relate the methylxanthines' effect on cultured glial cells to the developing nervous system, cholesterol synthesis was studied in the presence of 10−4M aminophylline. This represents a theophylline concentration in the culture medium that is of the same order of magnitude as that produced in whole brain of animals administered therapeutic doses of aminophylline. Under these conditions, cholesterol synthesis was reduced to approximately 60% of control after 48 and 72 hr.SpeculationCholesterol is the major lipid constituent of myelin and other cell membranes and reduction in synthesis of this lipid could have deleterious effects. C-6 glia are models of the glial stem cell found in developing brain before myelination,e.g., human brain in the perinatal period. This study raises the question whether serious reductions in brain cholesterol synthesis occurin vivoduring the treatment of neonatal apnea.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryCompensatory renal hypertrophy was studied in fetal lambs during midgestation. Functional adaptation was correlated with anatomica and biochemical changes by measuring glomerular filtration and clearance of para-amino hippurate (PAH). Normal intrauterine body growth and kidney growth by changes in RNA and DNA over a 72-hr period were studied in twin fetuses. Seventytwo hr after left uninephrectomy in single fetuses, there was a significant increase in weight of the renoprival right kidney as well as a significant increase in renal cortical content of RNA and DNA. The rate of increase in RNA was greater than the increase in DNA. Preliminary studies suggest that an increase in renal function parallels renal hypertrophy in fetal lambs.SpeculationIn midgestation, compensatory renal hypertrophy occurs by both an increase in cell size and by hyperplasia. The rate of increase is greater than that previously demonstrated in the postnatal period. Functional adaptation parallels renal compensatory hypertrophyin utero

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummarySera from patients with cystic fibrosis of the pancreas (CF) and normal human sera were assayed for the ability to inhibit sodium-dependent glucose transport in rat brush-border membrane vesicles. Fresh CF and age- and sex-matched control sera were both inhibitory when compared to physiologic saline. The inhibition by CF serum was 44 ± 13% (mean ± SD) at a final serum concentration of 6.7%, 67 ± 34% at 10% serum, and 68 ± 28% at 20% serum. The ratio of the inhibition of CF sera compared to that of control sera was 1.00, 0.78, and 0.93 at 6.7,10, and 20% serum concentrations, respectively. Although a slightly greater inhibition by CF serum was observed at a concentration of 10%, this is probably not significant because no difference could be detected at a concentration of 20% serum. Glucose transport in the presence of serum was sensitive to phlorizin indicating that the residual glucose transport was proceeding by the sodium-dependent glucose transport system. These findings suggest that CF serum does not specifically inhibit the sodium-dependent glucose transport system.The intravesicular space accessible to glucose was reduced in the presence of CF or control serum. Fresh CF serum was 1.4 times more effective than fresh control serum (P< 0.01). The presence of substantial vesicle-shrinking activity in control serum indicates that this activity cannot be considered specific for CF.SpeculationThe CF specific factor that inhibits sodium transport may be effective only with epithelial tissues capable of transporting sodium chloride against high concentration gradients, such as the epithelia of the ducts of the saliva and sweat glands, the colon, the distal renal tubules, and the renal collecting tubules.

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryAn oral loading of lysine (100 mg of lysine-HCL/kg) was performed in two patients, 18-and 23-yr-old, with a variant form of citrullinemia.Serum citrulline levels were approximately 10 times higher than control level and lysine levels were within the normal range, in contrast to the classical form of the disease in which serum citrulline is approximately 100 times normal levels and hyperlysinemia is usually present.After lysine loading, lysine levels rose sharply and clearance was decreased. Blood ammonia rose approximately 2.5 times. Lysine, citrulline, and arginine were markedly elevated in urine, collected 90–210 min after the lysine loading. Baseline homocitrulline and homoarginine excretion was elevated and increased further after the load.SpeculationLysine tolerance was impaired in two patients with citrullinemia, although baseline lysine levels were normal. Lysine seemed to be catabolized along the alternate urea cycle: lysine-homocitrulline-homoarginine-urea. Hyperammpnemia was aggravated, suggesting competition between lysine and ammonia for α-ketoglutarate and inability to remove ammonia completely by these two alternate pathways

ISSN:0031-3998    

出版商:OVID    

年代:1979

数据来源: OVID