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Biomedical subjects

B Persson

Publications and source records attributed to B Persson.

At least 325 records · Page 18Linked to original sources
PubMed1989

Procarboxypeptidase A activation segment compared to structures of other proteins.

The 94-residue activation segment of procarboxypeptidase A was compared with segments of other proteins. No significant homologies were observed towards other activation segments, but an inter-domain segment preceding the serine-protease part of complement factor B showed some structural relationships with the N-terminal region of the procarboxypeptidase A activation segment. This may reflect common functional and organizational patterns. In contrast, the present comparisons do not give functional or further sequence support to previously proposed structural homologies with helix-loop-helix (EF-hand) calcium-binding proteins.

Amino Acid Sequence↗
PubMed1989

A comparative evaluation of the 75 G OGTT and the 50 G OGTT during pregnancy.

The aim of the present study was to establish reference values for the diagnosis gestational diabetes (GD) by the 75 g OGTT using the 3 hr 50 g OGTT as a reference. Women with an area of greater than or equal to 42 AU in the 50 g OGTT were regarded as gestational diabetics. Sixty-one women with a 3 hr area of greater than or equal to 39 AU in the 50 g OGTT were subject also to a 3 hr 75 g OGTT within one week. 25/61 had GD according to the result of the 50 g OGTT. The 2 hr concentration in the 75 g OGTT had the highest correlation (r = 0.62, p less than 0.001) to the 3 hr-area in the 50 g OGTT. A 2 hr B-glucose concentration of greater than or equal to 8.0 mmol/l in the 75 g OGTT will give about the same number of GD patients (25/61) as a 3 hr-area of greater than or equal to 42 in the 50 g OGTT and have an acceptable sensitivity without too low specificity.

Adult↗
PubMed1989

Twenty-four hour excretion of urinary C-peptide in gestational diabetic women before and after treatment with diet or diet and insulin.

24-h urinary C-peptide excretion was studied in 119 women with gestational diabetes before and after treatment with diet or diet and insulin. The 24-h urinary C-peptide excretion in normal-weight gestational diabetic women at diagnosis was also compared to that of a healthy reference group. There was a wide variation in urinary C-peptide values which tended to be higher in normal-weight women with gestational diabetes at diagnosis compared to the reference group, but it did not reach statistical significance. Post partum gestational diabetic women had significantly higher urinary C-peptide excretion (p less than 0.002) than the reference group, indicating insulin resistance in women with gestational diabetes at this time. In 29 overweight women with gestational diabetes 24-h urinary C-peptide excretion did not significantly differ from that in normal-weight women with gestational diabetes. In 32 women with a more marked deviation in glucose tolerance (area greater than or equal to 46 mmol/l) 24-h urinary C-peptide values were significantly (p less than 0.05) higher than in 58 women with gestational diabetes with an area between 42 and 45.9 mmol/l. Both treatment alternatives, diet and diet plus insulin, significantly reduced postprandial blood glucose values (p less than 0.05) and urinary C-peptide excretion was significantly decreased (p less than 0.05).

Adult↗
PubMed1988

Isolation and characterization of porcine diazepam-binding inhibitor, a polypeptide not only of cerebral occurrence but also common in intestinal tissues and with effects on regulation of insulin release.

The polypeptide DBI (diazepam-binding inhibitor) has been purified from the porcine upper intestine, where it is abundant. Porcine mature DBI is composed of 86 amino acid residues and has a blocked N-terminus. The primary structure, the first DBI structure determined at the protein level, differs from those indirectly deduced for human and rat DBI at 11 and 17 positions, respectively. In total, the three mammalian DBIs differ at 22 positions but have exactly identical C-terminal 11-residue segments, highly charged and ending with C-terminal isoleucine. The porcine DBI inhibits both the early and the late phase of glucose-induced insulin release from the isolated perfused rat pancreas. Thus, the results identify by direct analysis the presence of DBI at a non-cerebral localization (gut), establish a novel structural form (porcine) and demonstrate a novel bioactivity (on insulin release). These aspects are of special interest in relation to the conserved segments, including the one at the C-terminal end, which may constitute functionally important parts of the polypeptide. It is possible that DBI belongs to a new family of gut polypeptides which inhibit glucose-mediated insulin release by hormonal and/or neurocrine mechanisms.

Amino Acid Sequence↗
PubMed1988

Identification of hormone-interacting amino acid residues within the steroid-binding domain of the glucocorticoid receptor in relation to other steroid hormone receptors.

Purified rat liver glucocorticoid receptor was covalently charged with [3H]glucocorticoid by photoaffinity labeling (UV irradiation of [3H]triamcinolone acetonide-glucocorticoid receptor) or affinity labeling (incubation with [3H]dexamethasone mesylate). After labeling, separate samples of the denatured receptor were cleaved with trypsin (directly or after prior succinylation), chymotrypsin, and cyanogen bromide. Labeled residues in the peptides obtained were identified by radiosequence analysis. The peaks of radioactivity corresponded to Met-622 and Cys-754 after photoaffinity labeling with [3H]triamcinolone acetonide and Cys-656 after affinity labeling with [3H]dexamethasone mesylate. The labeled residues are all positioned within hydrophobic segments of the steroid-binding domain. The patterns of hydropathy and secondary structure for the glucocorticoid receptor are highly similar to those for the progestin receptor and similar but less so to those for the estrogen receptor and to those for c-erb A.

Affinity Labels↗
PubMed1988

NBD-Cl modification of essential residues in mitochondrial nicotinamide nucleotide transhydrogenase from bovine heart.

Modification of mitochondrial nicotinamide nucleotide transhydrogenase (NADPH: NAD+ oxidoreductase, EC 1.6.1.1) with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl), followed by measurement of the absorption or fluorescence of the transhydrogenase-NBD adducts, resulted in a biphasic labelling of approx. 4-6 sulfhydryls, presumably cysteine residues. Of these 1-2 (27%) were fast-reacting and 3-4 (73%) slow-reacting sulfhydryls. In the presence of substrates, e.g., NADPH, the labelling was monophasic and all sulfhydryls were fast-reacting, suggesting that the modified sulfhydryls are predominantly localized peripheral to the NAD(P)(H)-binding sites. The rates of modification allowed the calculation of the rate constants for each phase of the labelling. Both in the absence and in the presence of a substrate, e.g., NADPH, the extent of labelling essentially parallelled the inhibition of transhydrogenase activity. Attempts to reactivate transhydrogenase by reduction of labelled sulfhydryls were not successful. Photo-induced transfer of the NBD adduct in partially inhibited transhydrogenase, from the sulfhydryls to reactive NH2 groups of amino-acid residue(s), identified as lysine residue(s), was parallelled by an inhibition of the residual transhydrogenase activity. It is suggested that a lysine localized close to the fast-reacting NBD-Cl-reactive sulfhydryl groups is essential for activity.

4-Chloro-7-nitrobenzofurazan↗
PubMed1988

Tumour calcification following repeated hepatic de-arterialization in patients: a preliminary communication.

A novel method of repeated hepatic de-arterialization is presented. A vascular occluder is placed around the hepatic artery and connected to an injection port. The hepatic artery can thereafter be occluded repeatedly. Patients with irresectable liver metastases from colorectal cancers were treated with occlusions of the hepatic artery for 1 h twice daily, in combination with intraperitoneal cyclic administration of 5-fluorouracil. The first three patients treated are presented. They all exhibited massive tumour calcifications in the liver reflecting tumour necrosis and resorption. This therapeutic principle must undergo further clinical trials.

Adult↗
PubMed1988

Intraperitoneal infusion of 5-FU in liver metastases from colorectal cancer.

Intraperitoneal 5-fluorouracil (5-FU) was given to eight patients with unresectable colorectal liver cancer and to one patient after radical hepatectomy. A subcutaneous intraperitoneal access device was implanted, and treatment consisted of continuous infusion of 1,000 mg 5-FU/d for 5 days, repeated every 6 weeks. Evaluation of treatment was performed after every two cycles of therapy. A total of 32 infusion cycles were given. The mean steady-state concentration of 5-FU was 0.56 +/- 0.04 mumol/l (mean +/- SEM), and the total body clearance was 10.0 +/- 0.71/min mean +/- SEM). The levels of 5-FU in peripheral venous blood were stable and reproducible. When incubated in whole blood at 37 degrees C the concentration of 5-FU fell rapidly and after 2 h, only 22% of the starting level remained. When kept ice-cold, 5-FU samples were stable. Patient acceptance was excellent, and the therapy was free from complications except for slight abdominal discomfort, not enough to require alleviation by analgesic drugs. Computerized tomography (CT) scan showed stationary tumor volume after two cycles of therapy in four of eight patients who could be evaluated. It is concluded that continuous intraperitoneal infusion of 5-FU produces stable and reproducible levels of the drug in peripheral venous blood, that 5-FU is degraded by blood cells at 37 degrees C, that the use of a subcutaneous access device makes the delivery easy and safe, and that the efficacy of the therapy seems to be similar to that obtained with hepatic arterial infusion.

Abdomen↗
PubMed1988

Adrenergic mechanisms during hypertension induced by sucrose and/or salt in the spontaneously hypertensive rat.

Spontaneously hypertensive rats received tap water, 1% NaCl, 5% sucrose or NaCl and sucrose in combination for 4 weeks. The blood pressure (tail plethysmography) and renal excretions of sodium and catecholamines were followed. After 4 weeks the noradrenaline turnover (disappearance after alpha-methyltyrosine) was assessed in the heart and brain. In pithed rats the pressor responses to intravenous noradrenaline and to electrical stimulation of the spinal sympathetic nerves (SNS) were determined together with the rise in plasma noradrenaline concentrations during the SNS. Salt alone caused an increase in peripheral sympathetic activity, measured as turnover of noradrenaline in the heart and spillover of noradrenaline in the urine, a modest enhancement of vascular responsiveness to noradrenaline and a blood pressure elevation. Sucrose alone increased the peripheral sympathetic activity but influenced neither the vascular responsiveness to noradrenaline nor the basal blood pressure. The largest increase in sympathetic activity and in blood pressure was observed with sucrose and salt in combination. The release of noradrenaline from the sympathetic nerve endings was not significantly influenced by any diet regime. The changes in noradrenaline turnover in the heart was accompanied by reciprocal changes in brain stem noradrenaline turnover.

Animals↗
PubMed1988

Reduction of protein intake decreases glomerular filtration rate in young type 1 (insulin-dependent) diabetic patients mainly in hyperfiltering patients.

The influence of different protein intake on renal function was studied in 16 Type 1 (insulin-dependent) diabetic patients, aged 15-23 years, with onset of diabetes before puberty and with a duration of diabetes between 5 and 20 years. The glomerular filtration rate, renal plasma flow, albumin excretion rate, and blood pressure were examined in a cross-over randomised order after 10 days on isocaloric diets with either 10% (i.e. 0.9 +/- 0.06 g.kg-1.day-1) or 20% (1.9 +/- 0.1 g.kg-1.day-1) of the calories as protein, the latter being equal to the recommended diet. Dietary compliance was evaluated using fractional phosphate excretion and overnight urea excretion. Glomerular filtration rate was lower after the low-protein diet compared to the usual protein diet (p less than 0.001). Patients with glomerular filtration rate above +2 SD of the normal mean on the usual protein diet (n = 6) exhibited the steepest fall in glomerular filtration rate with a mean decrease of 20 ml/min compared to 7 ml/min in those with initially normal glomerular filtration (p = 0.01). Filtration fraction tended to decrease on low protein diet, more so in initially hyperfiltering patients (p = 0.09). Renal plasma flow remained unchanged. In patients with elevated glomerular filtration rate on usual protein diet, albumin excretion rate and systolic, but not diastolic blood pressure, were decreased on low protein diet (p = 0.03 and p = 0.01, respectively) but not in initially normal-filtering patients. Mean blood glucose and serum fructosamine were unchanged on both diets.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Factors influencing the magnitude, duration, and rate of fall of B-cell function in type 1 (insulin-dependent) diabetic children followed for two years from their clinical diagnosis.

The pattern of fall in B-cell function measured as plasma and 24 h urinary C-peptide excretion, as well as levels of islet cell antibodies, insulin antibodies and metabolic parameters, were followed for two years in 39 children aged 1-17 years prospectively from clinical onset of Type 1 (insulin-dependent) diabetes. At onset 32/36 patients had measurable plasma C-peptide (median 0.13 nmol/l). Maximum values of fasting and postprandial plasma C-peptide were reached at a median duration of three months. Thereafter both plasma and urinary C-peptide declined linearly. The median value of the rate of fall in postprandial plasma C-peptide was 0.019 nmol.1-1.month-1. Age at onset was positively correlated to the maximum value of postprandial plasma C-peptide in each patient (rs = 0.57, p = 0.0001) and throughout the observation time positively correlated to fasting and postprandial C-peptide and to the 24 h urinary C-peptide excretion (rs range 0.35-0.70, p = 0.03-0.0001). The rate of fall of postprandial C-peptide was unrelated to age at onset and was strikingly parallel in different age groups. Islet cell antibodies were present in 87% of the patients at onset and decreased to 38% at 24 months. Islet cell antibody titres were not correlated to age at onset or to plasma or urinary C-peptide at any single observation. However, islet cell antibody negative patients had significantly higher (p less than 0.05) postprandial plasma C-peptide values at 1, 9, and 12 months of duration, compared to islet cell antibody positive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Primary structure of the hemoglobin alpha-chain of rose-ringed parakeet (Psittacula krameri).

The structure of the hemoglobin alpha-chain of Rose-ringed Parakeet was determined by sequence degradations of the intact subunit, the CNBr fragments, and peptides obtained by digestion with staphylococcal Glu-specific protease and trypsin. Using this analysis, the complete alpha-chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. The structure exhibits differences from previously established avian alpha-chains at a total of 61 positions, five of which have residues unique to those of the parakeet (Ser-12, Gly-65, Ser-67, Ala-121, and Leu-134). The analysis defines hemoglobin variation within an additional avian order (Psittaciformes), demonstrates distant patterns for evaluation of relationships within other avian orders, and lends support to taxonomic conclusions from molecular data.

Amino Acid Sequence↗