Simultaneous measurement of plasma renin activity (PRA), plasma aldosterone concentration (PA) and urinary aldosterone excretion (UAE) was made using the RIA method along with determination of Na and K balance in 1-week-old neonates with gestational age of 30–41 weeks (mean 35.9 weeks) and birth weight of 1,160–4,670 g (mean 2,680 g). It was demonstrated that PRA decreased from the value of 36.3 ± 6.3 ng/ml/h (mean ± SE) to a level of 10.2 ± 2.1 ng/ml/h (p < 0.001), PA did not change and UAE increased from 3.3 ± 0.8 to 7.8 ± 1.4 μg/day (p < 0.01) as the gestational age advanced from 30–32 to 39–41 weeks. There was no correlation between either PRA and PA or PA and UAE. PRA showed a significant positive correlation with urinary Na excretion (p < 0.001) and plasma K concentration (p < 0.05), but it was negatively related to Na balance (p < 0.001). Significant negative correlations were found between UAE and urinary Na excretion (p < 0.05), urinary Na/K ratio (p < 0.01) and plasma K concentration (p < 0.05); however, UAE positively correlated with Na balance (p < 0.01). It is concluded that, in response to renal salt wasting and to the subsequent negative salt balance, premature infants can augment their PRA above values found for full-term infants. Their adrenals, however, failed to respond adequately to this stimulation.
Group-specific complement-fixing antigen (GS antigen) was studied by the complement-fixation test in various avian and mammalian tumours, induced with the following strains of avian tumour virus ( A T V ) : Schmidt-Ruppin strain of Rous sarcoma virus ( S R -R S V ) , Prague strain of R S V ( P R -R S V ) , Fujinami sarcoma virus ( F S V ) and Bratislava 77 virus (B77V). All primary tumours induced in chicks by S R -R S V , FSV and B77V, as well as all duck tumours induced with B77V, contained high titres of GS antigen when studied with high-titre rabbit antiserum against purified GS antigen of avian myeloblastosis virus ( A M V ) . In three out of six B77V-induced rat tumours (two virus-producing and one non-virogenic) high titres of GS antigen were detected when examined with rabbit antiserum and with some rat sera obtained from tumour-bearing animals. In three remaining B77V-induced virogenic rat tumours (C21, C22 and C23), GS antigen was not detected with rabbit antiserum; however, sera obtained from these three tumourbearing rats contained high titres of GS antibodies when tested with different GS antigens. Positive results were obtained also with PR-RSV-induced virogenic rat tumour X C . However, all attempts to detect GS antigen in one S R -R S V induced virogenic rat tumour ( M R I ) gave negative results. Possible heterogeneity of A TV-induced GSantigen in mammalian tumours is discussed.
The regulation of murine mammary tumor virus (MuMTV) production by mammotropic hormones, hormonomimetic substances, and cyclic nucleotides was investigated. The virus produced in control and treated mammary tumor cell cultures was quantitated by measuring the supernatant reverse transcriptase activity in exogenous reaction using poly(rC).oligo(dG) as template-primer. Two days after exposure, the synthetic glucocorticoid, dexamethasone (DXMT), increased spontaneous MuMTV production at optimal concentration (0.1 mumol) up to ten times. Dibutyryl derivative of cyclic AMP had no effect on spontaneous MuMTV production, whereas the drug potentiated suboptimal concentrations of the glucocorticoid. Natural prostaglandins, potent agonists of adenylate cyclase catalyzing intracellular synthesis of cyclic AMP, enhanced both basal (up to five times) and DXMT-stimulated (up to 1.6 times) MuMTV replication. The MuMTV-stimulating activity of prostaglandins decreased in the order of PGA1 greater than PGE1 greater than PGB1 greater than PGF2 alpha. Prostaglandins can be replaced partially by norepinephrine and isoproterenol by enhancing the DXMT-mediated MuMTV stimulation, whereas these drugs remained without effect on spontaneous MuMTV production. Theophylline, an antagonist of cAMP-phosphodiesterase converting cAMP to AMP, enhanced the virus-stimulating activity of DXMT as well as of prostaglandins. The enhancement of MuMTV production by adenylate cyclase agonists do not correlate absolutely with the estimates of intracellular cAMP levels, since the highest amounts of cAMP has been repeatedly observed in cells treated with PGE1 and norepinephrine. The results indicate that besides hormones, other hormone-like substances and cyclic nucleotides may be involved in the complex mechanism of hormone-regulated MuMTV genome expression.
Plasma renin activity and plasma aldosterone concentration were measured by radioimmunoassay in eight newborn infants born vaginally to mothers on indomethacin treatment. Measurements were made in venous cord blood at birth and on the sixth day of life. The results were compared to those obtained in eight healthy control newborn infants of similar gestational age and birth weight. Maternal treatment with indomethacin was associated with a decrease of plasma renin activity (mean+SD) from 16.71 k2.76 ng/ml/hour in the control group to 9 a60 & 3.84 ng/ml/hour in the treated group. Plasma aldosterone concentration was lower in the cord blood of the treated group and a similar trend was demonstrated in the sixth day samples. It is suggested that the increased endogenous prostaglandin production during labour may be one of the factors responsible for the development of hyperactivity of renin-angiotensin-aldosterone system in the newborn.
Uciwrsity o f '~r n e , *itze;lanh. Ventilation for HMD csn lead t o BPD resu1tir.g ir! long lasting functiona.1 1w.g i r r p a i m t . W-etkr this alsc occurs when BPD does not develc~, i s nct kncwn. Therefore, k~ tested lung function i r . 18 children ( d i m age 7 7/12 years) who h2d k e n ventilated for HMC withcut BPD, iri 20 nm.-ventilated sib1ir.g~ (9 1C/12) a d ir. 20 ccntrols ~?at&.ed for gestaticmal age, birth wight, and. sex (6 2/12) . Methcd: Lung function was masurd by whole-bcdy p1eth)smcgraphy. Airway reactivity was assessed by carbachol provxation. Abnolmal lung fw.ctim was defined when hyperir,flation (TGV>130 % predictec!) ar,d/or m a l l ailway ohstrue t i m (maxinal expiratory flcw a t 50 % WG30 %) was present. Results: 10/18 ventilated children, 1/20 siblkgs (m.021) and 3/23 --rratched m t r o l s (p vs. ventilatedQ.01) have abnonnal lung function. The m r e n c e of ailway hkprreactivity was not different between +he grcvps (5/18, 4/20 a d 6/20). Cmcl.usion: Ventilation for HMIj nct resu1tir.g ir. EPD i s ilsscciated with hlperinflation ad./or collapse of the m a l l bronci-Loli a t a ~d i~ age of 7 7/12 years. The a b n o m l 1w.g function i s probably not due to w -e t i c predis~osition (sig. less a b r~o m l lung functior. in siblings, no difference hiseen sih:ings snd ccntrols, no difference in airway hyperreactivity) nor to p m k r i t y itself (sig. less s l n o m l it i e s in gestational age-and. birth v~i q h t m t c h d controls).. Vvtautas Basvs. P e t r a s K a l t e n i s . Donatas " .4 1 5 ~i a k i j l a i t i s . P e d i a t r i c ~e~a r t m e n t of V i l n i u s U n i v e r s i t y , 232600 iATP, V i l n i u s , L i t h u a n i a P i phellotypes a s s o c i a t e d w i t h d e c r e a s e d serum l e v e l of t h i s p r o t e i n a r e kn0i.m s o be n o r e p r e v a l e n t i n s u b j e c t s w i t h a v a r i e t y of d i s e a s e s . The aim of t h i s s t u d y was t o r e v e a l a p o s s i b l e l i n k a g e b e t v e e n d e f i c i e n t P i phenotypes and u r i n a r y t r a c t malfornat i o n s . 374 p e d i a t r i c p a t i e n t s were examined, i n c l u di n g 72 w i t h d u p l i c a t e d system, 97 w i t h hydronephrosis, w i t h r e n a l h y p o p l a s i a o r a p l a s i a , 179 w i t h v e s i c ou r e t e r a l r e f l u x (WR) and 3 w i t h p o l y c y s t i c kidney d i s e a s e . P i t y p i n g was done by i s o e l e c t r i c focusing. C o n t r o l group c o n s i s t e d of 1442 s u b j e c t s examined i n a p o p u l a t i o n study.A n i n c r e a s e d frequency of h e t e r ozygous phenotyoes PilllZ, PihIS and PiPP vias found i n c h i l d r e n w i t h %UR g r a d e 1 and 2 (PiMZ i n 3.%, PiMS i n 5.2$:, PiIvlF i n 2.6% of p a t i e n t s comparing w i t h 3.5%, 3.35 and 0.4$$, r e s p e c t i v e l y , i n t h e c o n t r o l s ) . These f i n d i n g s might suggest a c e r t a i n r o l e of modera t e l y d e c r e a s e d a n t i p r o t e i n a s e a c t i v i t y i n t h e appearance of low g r a d e WR ( p o s s i b l y...
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