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Biomedical subjects

B Persson

Publications and source records attributed to B Persson.

At least 289 records · Page 16Linked to original sources
PubMed1990

Enalapril reduces microalbuminuria in young normotensive type 1 (insulin-dependent) diabetic patients irrespective of its hypotensive effect.

The effect of enalapril on albumin excretion rate was studied in two groups of age- and sex-matched Type 1 (insulin-dependent) diabetic patients, aged 15-20 years, with persistent microalbuminuria greater than 20 micrograms/min. Group 1 contained six patients with systolic blood pressure greater than or equal to 75th percentile for age and sex, group 2 six normotensive patients. Enalapril (10-20 mg/day) was given for six months. Albumin excretion rate, glomerular filtration rate, renal plasma flow, blood pressure at rest and during exercise, and angiotensin converting enzyme activity were measured before, after three weeks' and six months' treatment and six months after treatment withdrawal. Albumin excretion rate decreased in all patients after three weeks' (mean decreases 55% in group 1, 65% in group 2) and six months' treatment (35% in group 1, 61% in group 2). Systolic blood pressure remained unchanged in both groups. Diastolic pressure was reduced after three weeks in group 1 (p = 0.001). No reduction in increment in systolic pressure during exercise test occurred in any group during treatment. Angiotensin converting enzyme activity decreased in all patients after three weeks (p = 0.001) and six months (p = 0.003). This correlated to the decrease in albumin excretion rate after three weeks (r = 0.79, p = 0.05) and six months (r = 0.59, p = 0.04). HbA1c, mean blood glucose and glomerular filtration rate remained unchanged during the study in both groups. Renal plasma flow tended to increase after three weeks' and six months' treatment in group 2 (p = 0.06, respectively) but not in group 1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Sea snake (Microcephalophis gracilis) hemoglobin: primary structure and relationships to other forms.

The hemoglobin of the sea snake Microcephalophis gracilis was purified and the primary structure of the alpha and beta chains determined. This is the first sea snake hemoglobin structure characterized, and apparently also the first complete structure of any snake hemoglobin (an alpha chain of a viper was known), allowing judgments of reptilian variants. Variations between the sea snake form and other reptilian forms are large (52-65 differences for the alpha chains), of similar order as those between the sea snake and avian (56-65 differences) or human (58 differences) forms. Functionally, 19 residues at alpha/beta contact areas and 7 at heme contacts are exchanged in relation to the human alpha and beta chains. Four positions of the sea snake hemoglobin contain residues thus far unique to this form. However, all replacements appear compatible with conserved overall functional properties.

Amino Acid Sequence↗
PubMed1990

Blood pressure and sympathetic activity in spontaneously hypertensive rats during food restriction.

Young (7 weeks) spontaneously hypertensive rats (SHR) were kept on food-restriction (33%) during 4 weeks with (0.3% saline as drinking water) or without sodium supplementation. Body weight and indirect systolic blood pressure (tail plethysmography) were followed each weak. During the last week of the intervention period 24 hour excretions of sodium, dopamine and noradrenaline were measured. Vascular pressor responses to noradrenaline were evaluated in pithed rats and the sympathetic nerve activity was assessed from the disappearance of endogenous noradrenaline in the heart after synthesis inhibition. Despite a clear retardation of the growth rate in food-restricted rats the development of hypertension was not influenced. Food-restriction was associated with a moderate suppression of sympathetic activity. Furthermore, the vascular pressor responses to noradrenaline were decreased but this was reversed following sodium supplementation. It is concluded that despite evidence of sympathetic suppression weight reduction does not reduce the blood pressure in SHR once the blood pressure has started to rise.

Animals↗
PubMed1990

Cardiovascular effects of irindalone, a new S2-serotonergic antagonist, in the rat.

Irindalone is a new antihypertensive agent with affinity to serotonin (5-HT2) receptors and at higher concentrations also to alpha 1-adrenoceptors. The present study was designed to evaluate the relative importance of the antagonism of central and peripheral alpha 1- and 5-HT2-receptors in the blood pressure lowering properties or irindalone after acute administration. In conscious Sprague-Dawley rats intravenous irindalone (0.05-1.5 mg/kg) dose-dependently reduced the blood pressure. In the same dose-range irindalone antagonized pressor responses to phenylephrine and electrical stimulation of the spinal sympathetic outflow (SNS) in the pithed rats, indicating that the acute blood pressure lowering effect is primarily related to the blockade of alpha 1-adrenoceptors. However, the concomitant 5-HT2-receptor blockade may contribute since irindalone in a dose (0.15 mg/kg) where it had no alpha-adrenoceptor blocking properties enhanced the hypotensive response to selective alpha 1-adrenoceptor blockade by prazosin (1 micrograms/kg). We found no evidence that central mechanisms contributed to the blood pressure lowering effect of irindalone. In anaesthetized rats irindalone (1 mg/kg) did not reduce the directly recorded sympathetic nerve activity. Intracerebroventricular administration of irindalone in conscious rats (10-100 micrograms) had no consistent effects on the blood pressure and did not enhance the hypotensive response to intracerebroventricularly administered prazosin (10 micrograms). Finally, the hypotensive response to irindalone was not influenced by depletion of central serotonin stores (by PCPA). It is concluded that the blood pressure lowering effect of irindalone following acute administration is related primarily to blockade of peripheral alpha-adrenoceptors but that the concomitant blockade of 5-HT2-receptors may contribute.

Animals↗
PubMed1990

Amino acid levels in the critically ill preterm infant given mother's milk fortified with protein from human or cow's milk.

Twenty preterm infants undergoing neonatal intensive care were randomly allocated to one of two feeding regimens: human milk enriched with either human milk protein (HMP) or adapted cow's milk protein (CMP). The birthweights (1076 +/- 301 g; 1031 +/- 309 g) and the gestational ages (28.4 +/- 1.6 weeks; 27.7 +/- 2.1 weeks) were comparable. The amount of protein added to the milk was set at 0.7 g/100 ml in order to provide a total supply of 3.0-3.5 g/kg/24 h. All infants received additional amounts of carbohydrate, calcium, phosphorous, and sodium chloride. Capillary whole blood amino acids were measured with high pressure liquid chromatography (HPLC). The amino acid levels did not differ significantly when the feeding groups were compared week by week, but the glycine/valine ratio was higher (p less than 0.05) in the HMP group after three weeks of fortification. Longitudinal changes after protein enrichment could be demonstrated in both groups. Alanine and threonine increased after one week (p less than 0.01) in both groups. Glycine in the HMP group peaked after two weeks (p less than 0.02), and valine in the CMP group increased (p less than 0.02) after one week on the feeding regimen. However, the amino acids never reached levels above those seen after a meal in normal term newborns. Other variables related to protein intake, such as protein and urea in serum, did not vary between the groups. Growth, expressed as gains in weight, length, and head circumference was poor but comparable. The quality of the protein, whether a human milk protein isolate or a cow's milk whey protein product, used for the fortification of human milk up to a protein load of 3.0-3.5 g/kg/24 h, did not cause any alterations of significance in the amino acid profiles of peripheral blood.

Amino Acids↗
PubMed1990

Insulin sensitivity and glucose-induced insulin response changes during adolescence.

Recently we reported that insulin resistance and glucose induced insulin release are inversely correlated to age in young healthy siblings of diabetic patients. To confirm this pattern of change with age, the subjects were reexamined after two years. The study was limited to the age groups with the lowest insulin sensitivity, i.e. 14.0-15.9 years for females and 16.0-17.9 years for males. All five girls and four of five boys showed an increased insulin sensitivity as measured by the somatostatin-insulin-glucose infusion test (p = 0.02). All subjects showed a decrease in fasting levels of insulin-like growth factor 1 (IGF-1) (p less than 0.01) during the observation period. All except one showed an increase in the levels of dehydroepiandrosterone sulphate (DHEA-S) (p less than 0.01). These data confirm that insulin sensitivity increases in the late teenage period. The parallelism to the changes of IGF-1 indicate that the pubertal changes in insulin sensitivity may partly be caused by growth hormone. Our data contradict the hypothesis that the low insulin sensitivity of puberty is due to the increased levels of DHEA-S.

Adolescent↗
PubMed1990

Effect of acute vascular fluid volume expansion on erythrocyte sodium transport in essential hypertension.

Evidence exists that volume expansion is associated with the appearance of a circulating sodium transport inhibitor. We have evaluated intra-arterial blood pressure (BP), central venous pressure (CVP), plasma renin activity (PRA), intraerythrocyte sodium content, erythrocyte sodium influx and rate constant of sodium efflux in 10 untreated primary hypertensive men (WHO stages I and II). The investigations were done during baseline conditions and after rapid intravenous infusion of 1 litre of saline (0.9% NaCl solution) over 15-20 min. Volume expansion caused an increase in CVP by 6.0 +/- 0.5 cmH2O (p less than 0.01), while BP only exhibited a slight increase. No significant changes in intraerythrocyte sodium content, sodium influx, sodium efflux rate constant or PRA were found after volume expansion compared to baseline. All patients with low normal PRA experienced a decrease in sodium efflux rate constant after volume expansion. We found a positive correlation between baseline PRA and change in sodium efflux rate constant after volume expansion (r = 0.62, p less than 0.05). At baseline the relationship between PRA and intraerythrocyte sodium content nearly reached statistical significance (r = 0.63, p = 0.054). These results may indicate that acute volume expansion influences the release of a circulating factor, modulating sodium transport in low-renin hypertension.

Adult↗
PubMed1990

The effect of cobalt on mitochondrial ATP-production in the rat myocardium and skeletal muscle.

Cobalt has been shown to accumulate in the myocardium of uraemic patients and has been suggested as a myocardial toxin inhibiting mitochondrial respiration. In order to study the cellular effects of cobalt exposure three groups of rats (n = 12 per group) were fed a diet containing 12% protein without supplementation or with 20 mg and 40 mg CoSO4 7 H2O/kg body weight/day respectively. After 8 weeks the hearts and soleus muscles were removed. Cobalt in tissues and in four cell fractions were analysed with neutron-activation analysis (ng/g wet weight and ng/mg protein respectively). Mitochondrial respiration was analysed as ATP-production rate using pyruvate + malate and palmitoyl-carnitine + malate as substrate. The ATP-production from pyruvate + malate was unchanged in both heart and skeletal muscle in the exposed animals. With palmitate as substrate, the heart muscle showed a slightly lower ATP-production rate (p less than 0.05) after the 20 mg cobalt dose, but the rate was unchanged in the group with higher cobalt intake. No changes in ATP-production rate from palmitate was observed in soleus muscle. The microsomal (100,000 g) fraction in the myocardial cells contained significantly higher cobalt concentrations compared to the mitochondrial fraction in both the unexposed (1.4 ng/mg protein vs 0.19, p less than 0.05) and exposed rats (53.4 ng/mg protein vs 13.2, p less than 0.005). In conclusion, cobalt showed a large accumulation in myocardial cells, without significant effects on mitochondrial ATP-formation rate from oxidation of pyruvate or palmitate and with the highest cobalt content contained in the microsomal (100,000 g) fraction.

Adenosine Triphosphate↗
PubMed1990

The intracellular distribution of cobalt in exposed and unexposed rat myocardium.

The intracellular distribution of cobalt was analysed in the myocardium of exposed and unexposed rats. The exposed rats were given a dietary cobalt supplementation of 40 mg CoSO4.7 H2O/kg body weight for 8 weeks. The mitochondrial fraction showed the greatest relative increase in cobalt: 0.09 ng/mg protein in the unexposed rats to 8.43 ng/mg protein in the exposed rats. In the exposed rats the submitochondrial particles had the highest levels of cobalt: 19.43 ng/mg protein, followed by the sarcoplasmatic reticulum: 12.3 ng/mg protein. The microsomal 44,000 g supernatant also showed an increase, although the levels remained low (0.51 ng/mg protein in the exposed animals). Apparently the calcium-storing organelles had the highest levels of cobalt. This could affect calcium flux in myocardial cells and, secondarily, tension development in cardiac muscle.

Animals↗
PubMed1990

Central hemodynamics and brachial artery compliance during therapy with isradipine, a new calcium antagonist.

Seventeen middle-aged males with sustained essential hypertension (WHO stage II) and diastolic blood pressures (BP) exceeding 100 mm Hg during a placebo run-in period completed a trial to assess the hemodynamic effects of isradipine, a new dihydropyridine calcium antagonist. The study was double-blind and placebo-controlled with a crossover design. Brachial artery compliance was assessed as the ratio of stroke volumes and simultaneous pulse pressure. During therapy with isradipine (all patients received 7.5 mg b.i.d.), highly significant reductions in supine systolic BP [from 184 +/- 16 to 162 +/- 20 mm Hg (mean +/- S.D.)] and diastolic BP (from 96 +/- 8 to 83 +/- 8 mm Hg) were observed. Heart rate was unchanged (69 +/- 3 vs. 73 +/- 2 beats/min) during chronic therapy. Total peripheral resistance was significantly reduced (from 24.8 +/- 9 to 17.4 +/- 5 units) while cardiac output was unchanged (6.0 +/- 1.9 vs. 7.2 +/- 1.8 L/min). Stroke volume was unchanged (92 +/- 25 vs. 100 +/- 25 ml/beat), and a significant (p less than 0.05) increase in brachial artery compliance (from 1.05 +/- 0.25 to 1.26 +/- 0.35 ml/mm Hg) was observed.

Ankle↗
PubMed1990

Plasma gastrin and somatostatin levels in infants during the first four postnatal days.

This study was designed to measure plasma gastrin and somatostatin levels in infants and to simultaneously investigate the infants' metabolic status as reflected by the body weight as well as by the blood levels of FFA, D-beta-hydroxybutyrate and glucose. Healthy infants (n = 94) who were born at term were studied cross-sectionally during their first four days of life. We found that the gastrin concentration (mean +/- SD) on the first day of life was 118 +/- 37 pmol/l. Subsequently the concentration decreased and reached its lowest value on the third day; 94 +/- 27 pmol/l (P less than 0.05). On the fourth day the mean concentration increased to the same level as on the first day. There was a significant (P less than 0.01) increase in somatostatin concentrations from 18 +/- 6 pmol/l on the first day to 26 +/- 7 pmol/l on the fourth day and the concentrations were highly related (P less than 0.0001) to postnatal age. We conclude that the decrease in gastrin concentration is probably related to the low volume of breast milk ingested during the first days after delivery, and therefore to the low secretory activity of the gastrin-producing cells. The infants' catabolic condition during that time was evidenced by the reduction in body weight, the decrease in plasma glucose level and the increase in FFA and D-beta-hydroxybutyrate levels. The gastrin increase found on the fourth day reflects most likely, the change in breast milk availability which occurs with the establishment of lactation. The mechanisms controlling the release of somatostatin remains to be established.

3-Hydroxybutyric Acid↗
PubMed1990

Effect of early dental health education for Finnish immigrant families.

The aim of the study was to evaluate whether or not the dental health of Finnish immigrant children would benefit from an extra session of information to the parents at the Child Health Centre, and whether this information, to be effective, should be given in Finnish. A further aim was to study the effect of this information on the parent's dental health knowledge and behaviour. Three groups of Finnish children, two test groups (FF and FS) and one control group (FC), and one control group of Swedish children (SC) took part in the study in Norrbotten and Stockholm county respectively. When the children were 6, 18 and 27 months of age, the parents of the Finnish test groups received information, the FF-groups in Finnish, and the FS-groups in Swedish. The parents of the Finnish and Swedish control groups were informed when the children were 6 and 18 months of age in Swedish. The various programmes were evaluated by comparing prevalence of dental caries of the children at the age of 3, as well as parents' attitudes to and knowledge of dental health and dental health behaviour. In Norrbotten 71% of the children in the FF-group were caries free compared to 53% in the FS-, 30% in the FC- and 80% in the SC-groups, and dfs averaged 1.7, 2.7, 6.0 and 0.9 for the groups respectively. The percentages of caries free children in Stockholm were 71, 58, 32 and 82 for the groups respectively and the mean dfs values 1.2, 2.1, 4.6 and 0.7. The data from the 36-month appointment showed equally good dental health knowledge and behaviour for the FF-groups as for the Swedish control groups.

Attitude to Health↗
PubMed1989

Eye lens zeta-crystallin relationships to the family of "long-chain" alcohol/polyol dehydrogenases. Protein trimming and conservation of stable parts.

zeta-Crystallin of guinea pig lens is distantly related to the family of zinc-containing alcohol/polyol dehydrogenases. The amino acid residues binding the catalytic zinc atom in the alcohol dehydrogenase are exchanged in zeta-crystallin, explaining lack of known enzyme activity, and those residues binding the noncatalytic zinc in the dehydrogenase are located in a segment absent from the crystallin. Mammalian alcohol dehydrogenase, polyol dehydrogenase, and zeta-crystallin therefore constitute a series of proteins exhibiting successive changes in subunit metal content, from two to one and probably zero zinc atoms, respectively. In common with tetrameric dehydrogenases, the crystallin lacks a loop structure present in the dimeric dehydrogenase. Significantly, the crystallin is tetrameric, and a correlation between extra subunit interactions and lack of the loop segment is indicated. The lacking segment in crystallin is extended, encompassing a second loop in the dehydrogenase. The greatest conservation corresponds to the coenzyme-binding domain of the dehydrogenases, the central parts of which are remarkably similar to those in the crystallin. Glycine is by far the most conserved residue and corresponds to positions at bends in the conformation of the alcohol dehydrogenase. The conservation of the stable parts of the fold, the absence of the loop structure, the lack of the metal atoms, and the presence of only a small proportion of oxidation-sensitive cysteine residues in crystallin (5 versus 15 in the beta 1 dehydrogenase subunit) suggest an increased stability of the lens protein and a derivation from the alcohol dehydrogenase family. This is compatible with the recruitment of stable enzyme structures for lens crystallin functions, with trimming of protein structures through these dehydrogenases or a yet unknown enzyme, and with multiple changes in the dehydrogenase family.

Alcohol Dehydrogenase↗
PubMed1989

Detection of IgG4 antibodies by immunoblotting in patients on vespid venom immunotherapy.

A nitrocellulose immunoblotting procedure has been used to monitor patient specific IgG antibodies during Hymenoptera vespid venom therapy. By using monoclonal antibodies in the immunoblot assay the relative IgG4 antibody levels could be analysed semiquantitatively. Treatment with vespid venom over 2 years resulted in rises in venom-specific IgG4 antibodies mostly directed towards antigen 5, phospholipase A and hyaluronidase. The use of high quality monoclonal antibodies in immunoblotting assays offers an improvement in the in vitro evaluation of venom immunotherapy.

Animals↗