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Biomedical subjects

K Olsson

Publications and source records attributed to K Olsson.

At least 19 recordsLinked to original sources
PubMed1992

Atrial natriuretic peptide attenuates pressor but enhances natriuretic responses to angiotensin II in pregnant conscious goats.

This study was designed to examine the actions of ANP in acute, ANGII-mediated hypertension during pregnancy. Effects on blood pressure, blood volume, and renal Na and K excretion were evaluated in conscious goats (n = 6). ANP (2 micrograms min-1), ANGII (0.5 microgram min-1), or ANGII+ANP (doses the same as for each peptide alone) was infused intravenously for 60 min. The pressor response to ANGII was reduced in pregnant goats. This reduction was seen in systolic, but not in diastolic pressure. ANP decreased pressure by 5-10 mmHg both in pregnancy and in non-pregnancy. When ANGII+ANP was infused, blood pressure initially rose as with ANGII but then declined. ANP suppressed only the elevated systolic pressure. Plasma protein concentration and haematocrit was reduced by ANGII but increased by ANP alone or together with ANGII, thereby implying fluid shift into the vasculature by ANGII and opposite movement by ANP. ANGII increased renal Na excretion to 1500 mumol min-1 in non-pregnancy, but only to half of that in pregnancy. ANP alone caused small natriuresis, but enhanced ANGII-induced natriuresis to near 3000 mumol min-1 in both non-pregnant and pregnant goats. In summary, ANP further attenuated the blunted blood-pressure rise due to ANGII in pregnant goats, and reduced plasma volume, but enhanced renal Na excretion as in non-pregnant goats. This implies that with the present combination ANP and ANGII caused a near maximal natriuretic response that was not modified by the systemic cardiovascular changes occurring in pregnant goats.

Angiotensin II↗
PubMed1991

Plasmid-identified Staphylococcus saprophyticus isolated from the rectum of patients with urinary tract infections.

Among 15 strains of Staphylococcus saprophyticus of various origin, 13 presented different plasmid patterns, making plasmid identification a useful epidemiological marker. In a consecutive study of 14 young female patients with urinary tract infection caused by S. saprophyticus, 6 patients were simultaneously positive for the same bacterium in the stools. Three paired samples contained the identical plasmid-identified clone of S. saprophyticus indicating that the rectum may be a reservoir of this urinary pathogen.

Adolescent↗
PubMed1990

Staphylococcus saprophyticus found to be a common contaminant of food.

The mode of transmission of Staphylococcus saprophyticus, a urinary tract pathogen, was investigated in three related studies. The presence of this organism was sought, during a period of 1 year, in 1331 specimens of various foods, in 920 beef and pork carcasses and on 107 cultures which had been inoculated directly from abattoir workers' protective gloves. Staphylococcus saprophyticus was found to contaminate 16.4% of the various food samples with a high prevalence of 34% in raw beef and pork. It was common in both domestic and imported raw meat products. There was no seasonal variation in the presence of S. saprophyticus in the samples obtained from carcasses. The bacterium was found in 69% of all cultures from the workers' protective gloves. We conclude that S. saprophyticus, originating from slaughtered animals, contaminates food and eventually colonizes the human intestinal tract.

Abattoirs↗
PubMed1990

Regional changes in sympathetic nerve activity and baroreceptor reflex function and arterial plasma levels of catecholamines, renin and vasopressin during naloxone-precipitated morphine withdrawal in rats.

The aim of the study was to examine regional changes in sympathetic nerve activity (SNA) and baroreceptor function and arterial plasma catecholamines, arginine vasopressin (AVP) and plasma renin activity during morphine withdrawal in chloralose-anesthetized rats. Dependence was induced by s.c. morphine base pellets. Adrenal, renal and splanchnic SNA and SNA from the lumbar sympathetic chain were recorded before and after i.v. injections of naloxone. Baroreceptor function was examined with phenylephrine-induced increases in mean arterial pressure. In separate experiments, arterial plasma norepinephrine, epinephrine, dopamine, plasma renin activity and AVP were measured before and after naloxone-precipitated withdrawal. Naloxone administration elicited an increase in mean arterial pressure and heart rate. Although renal SNA was inhibited by approximately 50%, adrenal SNA and lumbar SNA increased by approximately 400 and 80%, respectively. Splanchnic SNA did not change significantly. The baroreceptor-mediated inhibition of adrenal SNA was facilitated while that for renal SNA was attenuated. The arterial plasma level of norepinephrine was doubled and epinephrine increased almost 20-fold. AVP increased about 15-fold, whereas plasma renin activity showed only a minor increase after naloxone. This study shows that a marked differentiation of the SNA response occurs during morphine withdrawal in rats, which suggests an interaction between opioid receptors and the control of regional sympathetic output. Furthermore, large amounts of AVP and epinephrine are released, which probably contribute to the cardiovascular changes seen in the withdrawal phase.

Animals↗
PubMed1989

Fluid balance and arterial blood pressure during intracarotid infusions of atrial natriuretic peptide (ANP) in water-deprived goats.

The aim of this study was to investigate if atrial natriuretic peptide (ANP) plays a role in the control of water balance in goats and whether ANP affects the increase in mean arterial blood pressure (MAP) which accompanies drinking in water-deprived animals. Bilateral intracarotid infusions were made in female adult goats deprived of water for 48 h. ANP (1.5 micrograms min-1, n = 5, or 4.75 micrograms min-1, n = 5) was infused for 40 min. In control experiments isotonic saline (n = 7) was infused. The goats got access to water 35 min after the start of the infusions. During saline infusions they drank 2.9 +/- 0.4 litres, during the low dose of ANP 1.9 +/- 0.6 litres (n.s. vs saline), and during the high dose of ANP 0.6 +/- 0.2 litres (P less than 0.01 vs saline). Plasma vasopressin concentration did not change during saline infusions until after drinking, when it decreased. The vasopressin concentration increased in one goat after infusion of the low dose of ANP and in two goats after the high dose of ANP. The low dose of ANP caused no change in MAP in four goats, but MAP dropped in the one in which vasopressin concentration increased. MAP fell in all goats infused with the high dose (P less than 0.01), with the largest changes occurring in animals showing increased vasopressin concentration. During the act of drinking a temporary increase of MAP was observed when saline or the low dose of ANP was infused, but this response was attenuated during infusions of the high dose.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Fluid balance during heat stress in lactating goats.

Fluid balance and thermoregulation were studied during an acute heat load (maximal daily temperature, 38 +/- 1 degrees C; night temperature 27 +/- 1 degrees C) in six goats during lactation and non-lactation. The goats had free access to water for 1 day, followed by 29.5 h of water deprivation and then water was returned. With water available the goats increased water intake and urinary and milk water losses, while plasma and milk osmolality decreased. Water deprivation caused plasma osmolality and vasopressin concentration to increase most in lactating goats. Milk osmolality rose to values similar to plasma osmolality. Plasma cortisol increased in lactating goats at the end of dehydration. Renal Na+ excretion increased during dehydration in lactating goats. Evaporative heat loss was larger in lactating goats when hydrated, but became less than in non-lactating goats during dehydration. Lactating goats exhibited higher respiratory frequency and rectal temperature than non-lactating goats. In conclusion, our results show that goats increase the water turnover during heat stress if allowed to drink ad libitum, but when they are deprived of water lactating goats reduce water loss in urine, milk and by evaporation, and rectal temperature reaches higher levels than in non-lactating animals. This saving of water could allow milk production to be maintained for a longer time during heat stress.

Animals↗
PubMed1989

Atrial natriuretic peptide in pregnant and lactating goats.

Plasma concentrations of atrial natriuretic peptide (ANP) were measured in 6 goats during pregnancy, lactation and a nonpregnant, nonlactating (= control) period before and during a rapid iv load of 0.9% NaCl. The volume of the load was 20% of blood volume. The infusions increased central venous pressure by 7 +/- 1 mmHg during pregnancy and 8 +/- 1 mmHg during lactation. Before infusions plasma ANP concentrations were 5.7 +/- 0.7 pmol/l (control period), 10.8 +/- 1.8 pmol/l (pregnancy; P less than 0.05), and 6.5 +/- 1.5 pmol/l (lactation; NS). ANP increased significantly in all periods. Maximal values were 12.5 +/- 1.5 (control period), 25.5 +/- 2.3 (pregnancy; P less than 0.01 vs control period, P less than 0.05 vs lactation), and 13.0 +/- 1.6 (lactation; NS). Renal Na excretion increased similarly during pregnancy and control period, but slightly more during lactation. In 4 of the goats iv infusions of ANP (1 microgram/min, 60 min) were given. The infusions caused natriuresis during the control period, but not during pregnancy and lactation, despite more than 10-fold increases of plasma ANP levels. In conclusion, our results indicate that although plasma ANP concentration rose to high levels during acute NaCl loading in pregnant goats, this effect was not important for the natriuresis. Instead, the natriuretic response to ANP appears attenuated during pregnancy, and also during lactation.

Aldosterone↗
PubMed1987

Renal and hormonal responses to atrial natriuretic peptide infusions in goats on high and low sodium intake.

Synthetic atrial natriuretic peptide (ANP) was infused intravenously (1 microgram min-1; 60 min) in five goats during two series of experiments. For at least 4 weeks before the ANP infusions the goats received either no salt supplementation (= low sodium diet), or were given 16 g NaCl mixed with the food each day (Na = 274 mmol day-1; high sodium intake). The goats were changed between the treatments at random. ANP infusions caused diuresis, natriuresis and haemoconcentration during both diets. The urinary Na excretion increased about four-fold during the high sodium intake, and about 10 times during the low sodium intake. The urinary K excretion increased significantly during the low sodium diet, but decreased slightly during the high sodium intake. During both diets the K excretion became significantly lowered after the infusions. The mean glomerular filtration rate (GFR) was generally lower during the low sodium diet, but increased significantly during ANP infusions on both diets. The GFR returned to baseline immediately after the infusions, in contrast to urine flow and urinary Na excretion. Renal free water clearance increased slightly at the end of the infusion during the low sodium diet, but did not change during the high salt diet. Plasma renin activity (PRA) and plasma aldosterone concentration fell during ANP infusions in goats on the low sodium intake, but did not change significantly during the high sodium diet. These results indicate that the diuresis and natriuresis observed during intravenous ANP infusions in goats are mainly due to increased GFR.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldosterone↗