摘要:

To assess the National Institutes of Health extramural activity in the area of pediatric nephrology research, the rate of submission of grant applications to the National Institutes of Health and available indicators of the quality of these applications were analyzed. This was accomplished by utilizing the grant application files of the Division of Research Grants´ Statistics and Analysis Branch with the help of the Reports, Analysis and Presentation Section. Applications reviewed during the period 1980-1983 (May 1980 to January 1984 Council dates) were evaluated, and data from the 10 Study Sections most frequently involved with the review of nephrology applications were tabulated. Results showed that the number of pediatric nephrology applications submitted was quite low, whereas the approval rate was good for those that were submitted.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The transfer of radioactive riboflavin across the human term placenta has been studied in an invitroperfusion system. The clearance index (clearance riboflavin:clearance antipyrine) toward the fetus averaged 0.69 and the transfer index (clearance riboflavin:clearance Lglucose) averaged 3.40. The respective indices in the reverse direction were 0.25 and 0.87. Stepwise increases in the concentration of riboflavin in the maternal perfusate were associated with parallel increases in transfer rates, expressed as ng/min, up to concentrations approximating 100 ng/ml. Above that concentration, the transfer rates continued to increase at a slower rate. Concurrently, there was a reduction of the transfer index from 2.7 to 1.1 at 1000 ng/ml. With the fetal circulation closed, the placenta established a gradient toward the fetus over a period of 150 min of 1.7. The transferred radioactivity was identified as riboflavin by high-performance liquid chromatography, whereas that retained within the placenta was metabolized to flavin mononucleotide (33-75%). The observations indicate a very effective active transport system directed toward the fetus which is limited in capacity to low concentrations of riboflavin.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The role of glucocorticoids in the regulation of the postnatal development of ileal active bile salt transport was examined in the rat using the villus technique. Ileal taurocholate uptake was initially by passive transport alone on day 14 and 16 which changed to an active and passive transport mechanism at 18 days which persisted thereafter. The Michaelis-Menten constant (Km, mM) was unchanged between days 18 (0.67 ± 0.12 mM), 20 (0.84 ± 0.25 mM), 21 (0.49 ± 0.05 mM), 28 (0.59 ± 0.06 mM), and 49 (0.50 ± 0.05 mM) whereas the apparent maximal velocity nmol/mg(dry wt)/min declined after a peak at 18 days (18.17 ± 1.92 on day 18, 16.14 ± 1.89 on day 20, 14.65 ± 0.52 on day 21,11.40 ± 0.35 on day 28, and 10.51 ± 0.32 on day 49). Adrenalectomy performed in sucklings on day 14 with taurocholate transport studies on day 21 and in adults on day 42 studied on day 49 resulted in reductions in uptake at most study concentrations but no change in the Km (1.33 ± 0.54 in sucklings and 0.75 ± 0.14 mM in adults) or apparent maximal velocity [11.78 ± 2.06 in sucklings and 9.24 ± 0.65 nmol/mg (dry wt)/min in adults). Treatment of sucklings with corticosterone (5 mg/ 100 g body weight) on days 10-13 with study on day 14 and 16 did not produce precocious development of ileal active taurocholate transport; however, corticosterone treatment led to apparent increases in ileal permeability to taurocholate in both sucklings and adults. Glucocorticoids appear to play a minor, if any, role in the physiologic postnatal development of ileal active bile salt transport.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The conventional antimicrobial therapy of gram-negative infection in the newborn is the combination of ampicillin and an aminoglycoside, usually gentamicin or kanamycin. Although gentamicin and kanamycin have been used interchangeably, efficacies of the two drugs have not been carefully compared. In addition, the contribution of ampicillin to the outcome of neonatal gram-negative meningitis is controversial. We evaluated the activity of gentamicin and kanamycin alone and in combinations with ampicillin invitroand invivoagainst a K1Escherichia colistrain. In vitro, the E.colistrain was relatively sensitive to ampicillin, gentamicin, and kanamycin, with the minimal inhibitory and minimal bactericidal concentrations of 2 and 4, 2 and 2, and 4 and 8 µg/ml, respectively. Checkerboard determinations of minimal inhibitory and minimal bactericidal concentrations of drug combinations exhibited an indifferent response for both ampicillin + gentamicin and ampicillin + kanamycin. However, invivostudies using an experimental E.colibacteremia and meningitis model in newbown rats suggested that gentamicin was more effective than kanamycin. This was shown by more rapid bacterial clearance from the blood, a decreased incidence of meningitis in bacteremic animals, and improved survival. Furthermore, the addition of ampicillin improved the outcome of kanamycin, but not gentamicin, suggesting that the contribution of ampicillin may vary depending on the type of aminoglycoside used. These findings suggest that kanamycin is less effective than gentamicin in vivo against E.coliand should be used in combination with ampicillin to achieve an outcome comparable to that of gentamicin in this model of E.coliinfection.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Cerebral blood flow was estimated on 60 occasions in 15 well infants, 29-34 wk of gestational age, 5-17 days after birth, using 133-Xenon clearance after intravenous injection. The sleep state of the infants was determined by biparietal electroencephalography, clinical observation, and tracings of heart rate and respiration. Blood flow was 22% higher in the 11 estimations made during wakefulness, when compared to the 17 estimations made during quiet sleep. There was no difference between blood flow in active and quiet sleep. Also there was no difference between blood flow during periods of trace alternant and blood flow during periods of continuous electroencephalographic activity. It is suggested that flowmetabolism coupling is present in stable, preterm infants. The absence of an increase in cerebral blood flow during active sleep as compared with quiet sleep suggests that the neurophysiologic and neurometabolic mechanisms of rapid eye movement sleep are not yet fully developed in preterm infants.

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Treatment of unanesthetized newborn pigs with indomethacin trihydrate (5 ± 1 mg/kg, intravenous) decreased cerebral blood flow uniformly throughout the brain by 18-28% without changing cardiac output, arterial pressure, or arterial blood gases and pH. Breathing 10% O2, 9% CO2with the balance N2(hypoxia/hypercapnia) caused cerebral blood flow to increase from 102 ± 12 to 218 ± 19 ml/100 g-min. Intravenous administration of indomethacin during hypoxia/hypercapnia caused a uniform decrease in cerebral flow throughout the brain to levels (94 ± 5 ml/100 g-min) indistinguishable from those when the piglet was breathing ambient air. Further, 2.5 h later, the cerebral hyperemia caused by hypoxia/hypercapnia was attenuated markedly (129 ± 19 ml/100 g-min). Vehicle treatment did not alter resting cerebral blood flow or cerebral hyperemia in response to hypoxia/hypercapnia. Measurements of 6-keto-prostaglandin FIa, thromboxane B2, and prostaglandin E2demonstrated that intravenously administered indomethacin crossed the blood-brain barrier of newborn pigs in sufficient quantity to inhibit prostanoid release into the cerebrospinal fluid passing over the surface of the brain. The mechanism by which indomethacin reduces cerebral blood flow and attenuates cerebral hyperemia cannot be determined from the present experiments. We conclude that intravenous administration of indomethacin decreases cerebral blood flow and attenuates cerebral hyperemia induced by severe, combined hypoxia/hypercapnia in newborn pigs. (Pediatr Res 19: 1160-1164,1985)

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

An open circuit N2washout technique is described for the determination of functional residual capacity in infants. Either 100% O2or any oxygen/helium mixture can be used as the washing gas. The subject breathes the washing gas through a T-tube and the washed out nitrogen is mixed with this gas in a mixing chamber, placed into the exhalation part of the circuit. The N2concentration of the mixed gas is analyzed continuously, and the concentration signal is electronically integrated over time. Calibration of the system is accomplished by injecting known amounts of nitrogen or room air into the circuit. The gas flow through the system must remain constant and is adjusted to approximate peak inspiratory flow of the infant. In vitro testing of the system showed that the technique gives reproducible values (coefficient of variance2washed out (r=0.99). In vivo measurements in 10 cats confirmed the accuracy and reproducibility of the method when compared with N2collection. The technical advantages of the system are simplicity of components, absence of valves, easy calibration, low dead space, and no need to collect or measure expired gases. For the infant this means no added resistance during washout and no risk of hypoxia, hyperoxia, or hypercapnea. In the presence of pulmonary disease and poor gas mixing the washout period can be prolonged as needed. There is no lower limit of weight or size for functional residual capacity measurements in small infants or animals. (Pediatr Res 19: 1165-1169, 1985)

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

Cultured fibroblasts from mucolipidosis II (ML-II) patients demonstrated an elevated cystine content which increased with time in culture compared to fibroblasts from cystinotic patients or normal controls under the same conditions. In both cystinotic and ML-II cells the increased levels of cystine could be derived either from endogenous proteolysis or from in vitro supplementation of the cultured cells with cysteine-glutathione mixed disulfide. Cystine was depleted from both cell types by cysteamine. When cysteamine was replaced with complete medium, the cystine reaccumulated in both cystinotic and ML-II cells within 24 h, although a lag of 4 h was seen with ML-II cells. The intracellular location of the increased cystine in cultured fibroblasts was examined utilizing free-flow electrophoresis and found to be in the purified population of secondary lysosomes of both cystinotic and ML-II cells. White blood cell and hepatic cystine, which was greatly increased in cystinotic patients, was not elevated in ML-II patients. Compared to normal control fibroblasts the efflux of cystine from isolated granular fractions was virtually absent in cystinotic fibroblasts and considerably reduced in ML-II fibroblasts. The examination of such similarities and differences in cystine accumulation and transport in tissues from cystinotic and ML-II patients has provided some insight into the defects in these diseases. (Pediatr Res 19: 1170-1174, 1985)

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID

摘要:

The intestinal transport of riboflavin in the immature intestine of the suckling rat (14 day old) and its subsequent maturation in weanling (22 day old) and adult (90 day old) rats were investigated using the intestinal everted sac technique. The mucosal-to-serosal transport of 0.5 µ M riboflavin was linear with time for 30-min incubation and occurred at a rate of 4.6, 3.6, and 1.6 pmol/g initial tissue wet wt/min in suckling, weanling, and adult rats, respectively. The transport of 0.5 µ M riboflavin was higher in the jejunum than the ileum in all age groups. The transport system of riboflavin in all age groups was saturable, energy-, temperature-, and Na+-dependent. Kinetic parameters of the transport process were different. Apparent K, of the transport process was the same in suckling and weanling rats (0.12 and 0.11 µ M, respectively) but tripled in adult rats (0.35 µ M). On the other hand, a progressive decrease in Vmaxfrom 166 to 122 to 54 pmol/g initial tissue wet weight/30 min was observed in the suckling, weanling, and adult rats, respectively. The present study demonstrates that the characteristics of the transport process of riboflavin is similar in suckling, weanling, and adult rats and occurs by an energy-, temperature-, and Na+-dependent carrier-mediated process. However, the affinity and the activity (or the number) of the transport carriers of riboflavin decrease with maturation. (Pediatr Res 19: 1175-1178, 1985)

ISSN:0031-3998    

出版商:OVID    

年代:1985

数据来源: OVID