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Biomedical subjects

P Belfrage

Publications and source records attributed to P Belfrage.

At least 91 records · Page 5Linked to original sources
PubMed1985

Intracervical versus intravaginal PGE2 for induction of labor at term in patients with an unfavorable cervix.

In a randomized double-blind study we evaluated the effects on cervical ripening and labor induction of 0.5 mg PGE2 in gel given intracervically and 2.0 mg PGE2 given as a vaginal suppository. All patients were at term with unfavorable cervical scores. The indications for induction were toxemia, diabetes mellitus, Rh-immunization, or intrauterine growth retardation. Significantly better results for both cervical priming and labor induction were obtained after intracervical PGE2-gel application than after treatment with placebo or vaginal suppositories. Eleven out of 19 patients (58%) were delivered within 24 h after intracervical PGE2-gel compared to two out of 19 patients given placebo (p less than 0.01). In patients not delivered 24 h after the start of treatment, the mean cervical score had changed from 3.7 to 6.0 (p less than 0.05) after PGE2-gel application compared to a change from 3.9 to 4.3 after placebo treatment (n.s.). The outcome after treatment with PGE2 suppositories did not differ significantly from that with placebo treatment. In a subsequent study 25 patients were given 0.5 mg PGE2-gel intracervically. The results were consistent with those obtained in patients receiving PGE2-gel intracervically in the double-blind study. Few side effects were noted. No patient complained of gastro-intestinal discomfort but increased myometrial activity was observed in two patients; one after placebo and the other after active intracervical PGE2-gel treatment. The hyperactivity was readily countered with the beta 2-agonist, terbutaline. All infants were born in good condition with Apgar scores of 7 or more within 5 min. At pediatric examinations at 1 week and at 6 months of age all children seemed healthy.

Administration, Topical↗
PubMed1985

Hormone-sensitive lipase from swine adipose tissue: identification and some properties.

Swine adipose tissue hormone-sensitive lipase, purified 475-fold to 10% protein purity, has been identified as a polypeptide of Mr = 84,000. The enzyme has high specific activity against tri-, di- and monoacylglycerols, as well as cholesterol esters, and is inhibited by millimolar NaF, and micromolar HgCl2 and DFP. The enzyme polypeptide serves as a substrate for cyclic AMP-dependent protein kinase. The characteristics of the hormone-sensitive lipase from swine adipose tissue are similar to those reported previously for the enzyme from rat. They differ from those reported for the lipase from chicken adipose tissue, and possible reasons for these differences are discussed.

Adipose Tissue↗
PubMed1985

Bioconversion of arachidonic acid in human pregnant uterine cervix.

The in vitro conversion of [14C]arachidonic acid by endocervical mucosa and cervical tissue specimens obtained in first trimester (9-12 w) and term pregnant patients (37-39 w) was studied in whole-cell homogenates. All radiolabelled products of the arachidonic acid cascade were extracted, purified and separated utilizing silicic acid chromatography, thin-layer chromatography and reversed phase partition chromatography and identified with radio-gas chromatography and gas chromatography-mass spectometry. Both types of tissue produced PGF2 alpha and PGE2, as well as TxB2. In cervical tissue specimens there was a significant increase in the production of all these three prostaglandins as the pregnancy progressed, whereas no such difference was seen in homogenates of endocervical mucosa. In both endocervical mucosa and cervical tissue specimens there was a highly significant increase in the production of a so-far unknown compound(s), in samples from term patients as compared with samples from first-trimester patients. The possible participation of this metabolite of [14C]arachidonic acid in the regulation of cervical ripening is discussed.

Arachidonic Acids↗
PubMed1985

Molecular mechanisms for hormonal control of adipose tissue lipolysis.

The fast-acting lipolytic hormones and insulin regulate adipose tissue lipolysis through control of the activity of hormone-sensitive lipase. This enzyme catalyzes the rate limiting step of adipose tissue lipolysis--the hydrolysis of stored triacylglycerols. The isolated enzyme is rapidly phosphorylated and activated by cyclic AMP-dependent protein kinase, with 1 mol of phosphate incorporated per mol of lipase Mr = 84000 subunit into a single serine residue. The enzyme is dephosphorylated and deactivated by protein phosphatases type 1, 2A and 2C. In the intact, isolated adipocytes the enzyme incorporates phosphate in the absence of hormonal stimulation into a specific 'basal' phosphorylation site. The phosphorylation of this 'basal' site (into a serine residue) is not accompanied with any change of the activity of the enzyme and is not influenced by hormones. The fast-acting lipolytic hormones induce a phosphorylation of another serine residue in a 'regulatory' phosphorylation site, which is identical to that phosphorylated in the isolated enzyme by cyclic AMP-dependent protein kinase. Following the phosphorylation of the 'regulatory' site the activity of the lipase, and consequently the rate of lipolysis, is increased almost 50-fold. Insulin causes a rapid net dephosphorylation of the lipase and exerts its well-known anti-lipolytic action. Half-maximal inhibition of both phosphorylation and activity occurs at an insulin concentration of about 25 pM. The mechanism(s) whereby insulin causes its effects is unknown but apparently to a large extent involve reduction of the cellular cyclic AMP level.

Adipose Tissue↗
PubMed1984

Direct evidence for protein phosphatase-catalyzed dephosphorylation/deactivation of hormone-sensitive lipase from adipose tissue.

Incubation of purified hormone-sensitive lipase, 32P-phosphorylated with the catalytic subunit of cyclic AMP-dependent protein kinase and [gamma-32P]ATP-Mg2+, with partially purified protein phosphatase from the same tissue caused a rapid decrease of the 32P content of the enzyme protein. Deactivation of the lipase towards emulsified trioleoylglycerol was temporally related to the dephosphorylation with approx. 80% decrease of both phosphorylation and activity within 30 min. Addition of ATP-Mg and cyclic AMP-dependent protein kinase to the dephosphorylated lipase was shown to rephosphorylate and reactivate the enzyme. These findings are the first direct demonstration of reversible protein phosphatase-catalyzed dephosphorylation/deactivation of hormone-sensitive lipase.

Adenosine Triphosphate↗
PubMed1984

Transient increase of early-onset group B streptococcal septicemia.

Since 1976, all cases of neonatal group B streptococcal (GBS) septicemia/meningitis have been registered at two Swedish University Hospitals. A significant increase in the number of infants contracting early-onset GBS-septicemia was noticed at one clinic in 1981, from 1-3 cases per yr to 8 cases. Six months prior to this increase the number of deliveries increased from about 1500 per yr to nearly 3000 per yr. It is suggested that external factors, e.g., subtle changes in the nursing combined with an extended disadvantage at the ward might influence the development of early-onset GBS septicemia.

Humans↗
PubMed1984

Hormonal regulation of hormone-sensitive lipase in intact adipocytes: identification of phosphorylated sites and effects on the phosphorylation by lipolytic hormones and insulin.

In isolated adipocytes, fast-acting lipolytic hormones and insulin have been shown previously to control lipolysis by regulating the activity of hormone-sensitive lipase, the rate-limiting enzyme, through an increase or decrease, respectively, of the extent of phosphorylation of the enzyme. Here, we demonstrate that exposure to lipolytic hormones (corticotropin, noradrenaline) led to phosphorylation at two sites on the Mr 84,000 lipase subunit. One, designated "basal site," was phosphorylated also in the absence of any hormonal stimulation, its phosphorylation apparently not being influenced by hormones. The second, designated "regulatory site," was identical to that phosphorylated by cyclic AMP-dependent protein kinase on the isolated lipase. The regulatory site was not appreciably phosphorylated in the absence of hormones, but exposure of the cells to noradrenaline increased its phosphorylation extent to that of the basal site. Insulin or the beta-adrenergic antagonist propranolol decreased the extent of phosphorylation of the regulatory site to the low level before stimulation, apparently without effect on the basal site. Phosphoserine was the only phosphorylated amino acid residue at both sites. Limited proteolytic digestion indicated that the two sites were separated by less than about 170 amino acid residues. Thus, control of adipose tissue lipolysis by fast-acting lipolytic hormones and by insulin is exerted through the regulation of the phosphorylation state of a single phosphoserine residue in the hormone-sensitive lipase.

Adipose Tissue↗
PubMed1984

The antilipolytic, insulin-like effect of growth hormone is caused by a net decrease of hormone-sensitive lipase phosphorylation.

The mechanism of the antilipolytic effect of GH and the cause of refractoriness to its own action was studied in isolated rat adipocytes. Human GH rapidly inhibited catecholamine-stimulated lipolysis rate, with a time course similar to that of insulin, but only in cells which had been preincubated in the absence of GH for 2-3 h. Half-maximal inhibition was obtained with a GH concentration of 100 ng/ml. Parallel determinations of the lipolysis rate (with a pH-stat titration technique) and the extent of phosphorylation of hormone-sensitive lipase, the rate-controlling enzyme in adipose tissue lipolysis, were made. The extent of lipase phosphorylation, 1.7-fold enhanced by previous noradrenaline stimulation, was rapidly reversed by addition of GH, and the decrease was followed by a parallel decrease in the lipolysis rate. The time course and magnitude of these effects was similar to those obtained with exposure of the cells to insulin, indicating that the antilipolytic effect of both hormones was exerted through the same mechanism: a net dephosphorylation of the hormone-sensitive lipase. To study the refractoriness of the fat cells to the action of GH (which was not found with insulin) adipocytes were prepared from hypophysectomized rats 24 h after surgery. With such cells no preincubation was required to obtain the effects of GH on the lipolysis rate and extent of hormone-sensitive lipase phosphorylation. The effects of GH on both of the parameters studied were similar to those obtained in nonhypophysectomized rats. These results suggest that the refractoriness of the fat cells to GH may be explained by a functional inhibition at a site(s) in the series of metabolic events initiated by GH action, which precedes the activation of the hormone-sensitive lipase.

Adipose Tissue↗
PubMed1984

Effects of naloxone on newborn infant behavior after maternal analgesia with pethidine during labor.

Infants born to mothers receiving 100 mg of pethidine during labor, were randomly given either 100 micrograms of naloxone (n = 14) or 0.25 ml 0.9% NaCl (n = 13) one hour post partum. Infant behavior was assessed with the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) and the Broussard Neonatal Perception Inventory (NPI). No differences in cluster scores on the BNBAS were found between the two groups. Both groups improved scores over time in 4 out of 7 clusters. On the NPI, mothers assessed naloxone infants as having less optimal behavior than did the control mothers. The results of this study on the effects of naloxone on infant behavior and maternal perception of newborn behavior do not warrant administration of naloxone after maternal analgesia with pethidine in the absence of clinical evidence of respiratory depression in the newborn.

Adult↗
PubMed1984

Causes and consequences of maternal and fetal sympathoadrenal activation during parturition.

The sympathoadrenal system is activated in both the mother and fetus during parturition. The fetal plasma catecholamines may reach extremely high levels during deliveries complicated by asphyxia. Increased maternal sympathoadrenal activity during labour or caesarean section may negatively affect uteroplacental blood flow with possible adverse effects on the fetus. Such an increase may be avoided by adequate maternal pain relief and by the sympathetic blockade which follows epidural anaesthesia. Fetal sympathoadrenal activation during parturition seems on the contrary to be of positive functional importance both for fetal circulatory regulation in utero a well as for the neonatal adaptation in terms of pulmonary function and metabolic stimulation.

Adrenal Glands↗
PubMed1983

Phosphorylation of hormone-sensitive lipase by cyclic AMP-dependent protein kinase.

Hormone-sensitive lipase, detergent-solubilized and purified from rat adipose tissue, was phosphorylated with the catalytic subunit of cyclic AMP-dependent protein kinase from the same tissue. Maximally 1.05 +/- 0.05 (mean +/- S.E. (n = 3) ) mol of phosphate/mol of hormone-sensitive lipase Mr = 84,000 subunit was incorporated. Phosphoserine was the only phosphorylated amino acid residue. A single phosphorylation site was demonstrated by digestion with Staphylococcus aureus V8 protease and trypsin that produced a single acidic phosphopeptide of about 10 amino acid residues length, which was isolated by two-dimensional electrophoresis-thin layer chromatography. Enzyme activity was enhanced, 2.5-fold against trioleoylglycerol, concomitant with phosphorylation, with half-maximal effect within 30 sec, a rate of phosphorylation of the enzyme comparable to that obtained in vivo (Nilsson, N. O., Strålfors, P., Fredrikson, G., and Belfrage, P. (1980) FEBS Lett. 111, 125-130). The initial rate of phosphorylation was approximately half that with phosphorylase kinase as substrate. The effects of modifications of hormone-sensitive lipase and of various additions and variation in pH were examined.

Adipose Tissue↗
PubMed1983

Positional specificity of hormone-sensitive lipase from rat adipose tissue.

Hormone-sensitive lipase, purified from rat adipose tissue (Fredrikson, G., Strålfors, P., Nilsson, N. O., and Belfrage, P. (1981) J. Biol. Chem. 256, 6311-6320), has been incubated with tri-, di-, and monooleoyl[3H]glycerol, and the acylglycerol reaction products were isolated by thin layer chromatography on silicic acid, impregnated with boric acid. Trioleoylglycerol was hydrolyzed with the intermediate accumulation of monooleoylglycerol, mainly the 2-isomer, and a small amount of 1,2(2,3)-, but no measurable, 1,3-dioleoylglycerol. 2-Monooleoylglycerol was also the major acylglycerol reaction product from 1,2(2,3)-dioleoylglycerol hydrolysis, which occurred at a Vmax of 60% of that with the 1,3-isomer. Part of the 1(3)-monooleoylglycerols found were formed by acyl migration, but 2-ester bond cleavage was directly demonstrated by the use of 1,3-dioleoyl-2-[14C]oleoyl[3H]glycerol as substrate, and by determination of the 14C/3H ratios of the acylglycerol reaction products. Based on the hydrolysis of specific monooleoylglycerol isomers, it was estimated that the 1(3)-ester bonds of the acylglycerols were hydrolyzed 3- to 4-fold faster than the 2-ester bonds. The main lipolytic reaction sequence catalyzed by hormone-sensitive lipase is thus triacylglycerol leads to 1,2(2,3)-diacylglycerol leads to 2-monoacylglycerol. However, the preference for the 1(3)-ester bonds is less marked than that of, e.g. pancreatic and lipoprotein lipase.

Adipose Tissue↗
PubMed1983

Experience with an industrially manufactured gel PGE2 for cervical priming.

An industrially manufactured ready-to-use PGE2 gel for cervical ripening was clinically evaluated. The study included 42 primiparous and eight multiparous women with an unfavourable cervix (Bishop score less than or equal to 5) admitted to hospital for induction of labour on medical grounds. PGE2, 0.5 mg, in 2 ml triacetin gel was instilled into the cervical canal. In nine patients (18%) the gel induced labour and subsequent delivery. In the remaining women the mean Bishop score increased from 3.0 to 7.7 during a 24-h period and labour was induced by either i.v. oxytocin or PGF2 alpha. None of the 50 patients experienced gastrointestinal side effects during pretreatment with PGE2. In 50% of the patients slight uterine contractility was noticed. All patients went into labour. The incidence of Cesarean section was 10%. Except for two patients treated because of intrauterine fetal death there was no perinatal mortality. The 5-min Apgar score was 8 or more in all newborn but 1. The main advantage of the new gel is that it is ready to use without any mixing procedure. Moreover, the stability of PGE2 is sufficient to allow routine clinical use.

Adolescent↗
PubMed1983

Electrophoretic elution of proteins from polyacrylamide gel slices.

A method for electrophoretic elution of proteins from polyacrylamide gel slices is described. Eluted proteins were retained by a discontinuous conductivity gradient (M. Otto and M. Snejdárková, Anal. Biochem. 111, 111-114 (1981)). The method has been adapted to slices from slab gels and gels that have been stained and destained. Proteins were eluted as their sodium dodecyl sulfate complexes. Minute amounts of proteins (0.1 microgram) were recovered in high yield (85-95%) in 2 h in less than 0.1 ml volume.

ATP Citrate (pro-S)-Lyase↗
PubMed1983

Obstetrical paracervical block with chloroprocaine or bupivacaine. A comparison.

Obstetrical paracervical block was randomly administered to 47 patients, using either 2% chloroprocaine or 0.25% bupivacaine. Analgesia and onset of analgesia were similar for both drugs, but the duration of chloroprocaine was only about half that of bupivacaine (35 min versus 66 min). Fetal bradycardia was encountered in one case after chloroprocaine and in two cases after bupivacaine. It is concluded that chloroprocaine plain is not very suitable for obstetrical paracervical block due to its short duration of action.

Anesthesia, Obstetrical↗
PubMed1982

Properties and purification of the catalytic subunit of cyclic AMP-dependent protein kinase of adipose tissue.

The catalytic subunit of cAMP-dependent protein kinase from rat adipose tissue was purified to apparent homogeneity by making use of the differential binding of the holoenzyme and the free catalytic subunit to CM-Sephadex and by gel chromatography. Stability and yield was improved by inclusion of nonionic detergent in all steps after dissociation of the holoenzyme. Isoelectric focusing separated enzyme species with pI values of 7.8 and 8.6-8.8. The amino acid composition was similar to the enzyme purified from other tissues. Enzyme activity was markedly unstable in dilute solutions (less than 5 micrograms/ml). Additions of nonionic detergent, glycerol, bovine serum albumin and, especially, histones stabilized the enzyme. With protamine, the catalytic subunit had an apparent Km of 60 microM and Vmax of 20 mumol X min-1 X mg-1, corresponding values with mixed histones were 12 microM and 1.2 mumol X min-1 X mg-1. With both protein substrates the apparent Km for ATP was 11 microM. Concentrations of Mg2+ above 10 mM were inhibitory. Histone phosphorylation was inhibited by NaCl (50% at 0.5 M NaCl) while protamine phosphorylation was stimulated (4-fold at 1 M NaCl). Inorganic phosphate inhibited both substrates (histones: 50% at 0.3 M, and protamine: 50% at 0.5 M). pH optimum was around pH 9 with both substrates. The catalytic subunit contained 2.0 (range of three determinations, 1.7-2.3) mol phosphate/mol protein. It was autophosphorylated and incorporated 32Pi from [gamma-32P]ATP in a time-dependent process, reaching saturation when approx. 0.1 mol phosphate/mol catalytic subunit was incorporated.

Adipose Tissue↗