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Biomedical subjects

L Jansson

Publications and source records attributed to L Jansson.

At least 253 records · Page 14Linked to original sources
PubMed1985

Ablation of serotonergic nerves in the rat pancreas. Lack of effects on hormone secretion and intrinsic blood flow.

The aim of the present study was to evaluate the physiological role of intrapancreatic serotonergic nerves for endocrine pancreatic function. The specific uptake of [3H]5-hydroxytryptamine (5-HT) into pancreatic slices from the rat was completely abolished after an intrapancreatic injection of 5,7-dihydroxytryptamine (5,7-DHT). Since also high-affinity uptake of [3H]5-HT was absent it was concluded that intrapancreatic serotonergic nerves were destroyed. The effects of this selective denervation on glucose-stimulated insulin and somatostatin secretion were investigated with the aid of perfused rat pancreatic glands removed 3, 7 or 14 days after the injection of 5,7-DHT. Neither the basal release of these hormones nor their response to a glucose challenge was significantly altered by the ablation of the intrapancreatic serotonergic nerves. The microsphere technique was used to investigate the blood flow through the pancreatic islets in rats injected intrapencreatically with 5,7-DHT 4 days previously. No significant changes in either the whole pancreatic blood flow or the islet blood flow could be demonstrated. These result show that in normal physiological conditions the intrapancreatic serotonergic nerves do not affect the hormonal release from or the blood flow through the endocrine pancreas.

5,7-Dihydroxytryptamine↗
PubMed1985

Incidence of arthritis and autoreactivity of anti-collagen antibodies after immunization of DBA/1 mice with heterologous and autologous collagen II.

Native type II collagens of rat, chick, bovine, human and murine origin have been used for immunization of male and female DBA/1 mice of different ages. The four heterologous collagens were able to induce arthritis in both male and female mice although the incidence of arthritis was higher in males. The onset of arthritis was sudden with severe lesions starting to appear 5- to 6-weeks after immunization. Mouse collagen II, on the other hand, caused arthritis exclusively in males. The onset of arthritis was in the latter case less dramatic and usually delayed until 12- to 14-weeks post immunization. Antibody production against both the immunogen and other type II collagens, including mouse collagen was seen in both arthritic and non-arthritic animals, and antibody titres against both the collagen used for immunization and mouse collagen were higher in the sera from arthritic than in identically immunized non-arthritic animals. Total amounts of auto-anticollagen II antibodies were, however, more dependent on which collagen preparation was used for immunization than on whether the immunized mice developed arthritis or not. These results indicate that arthritis induction in mice is not dependent solely on the levels of autoreactive anti-collagen II antibodies.

Animals↗
PubMed1984

Vasoactive drugs and elastic properties of human arteries in vivo, with special reference to the action of nitroglycerine.

Pulsatile changes in the volume of an arm segment were recorded with an air-filled plethysmograph and related to intra-arterial blood pressure. Alterations in transmural arterial pressure were obtained by changing the pressure in a large chamber surrounding the entire arm. Arterial compliance values were calculated in late diastole when pressure and volume changes were slow. Compliance varied with transmural arterial pressure in a hyperbolic manner, rising steeply at low pressure. Noradrenaline and hypertensin did not change the arterial compliance values, while dihydroergotamine reduced them. Nitroglycerine caused a pronounced increase in compliance values in doses that did not change cardiac output and arterial pressure.

Adult↗
PubMed1984

Intestinal absorption of vitamin E in low birth weight infants.

Intestinal absorption of dl-alpha-tocopheryl acetate was studied in low birth weight infants. Vitamin E was given from the first day of life, either as a water-soluble (Ephynal) or as a lipid-soluble preparation (E-vitamin). Serum-alpha-tocopherol concentrations were determined before treatment and on days three and seven. Treatment with both vitamin E preparations increased serum-alpha-tocopherol on day three and seven. The mean serum-alpha-tocopherol +/- SD on day seven were 41.4 +/- 10.7 mumol/l for the Ephynal group and 26.7 +/- 12.5 mumol/l for the E-vitamin group, this difference being statistically significant (p less than 0.025). Oral feeding seems to influence the absorption of tocopherol from E-vitamin, as the infants with the highest serum-alpha-tocopherol concentrations were those with the highest oral/total feeding ratios. In infants with birth weight less than 1 000 g treatment with 25 mg Ephynal/day was found to increase serum-alpha-tocopherol on day seven to 46.9 +/- 12.3 mumol/l (mean +/- SD). This concentration is comparable to those reported by others using higher doses of oral vitamin E.

Humans↗
PubMed1984

Diabetes in pregnancy: decreased placental blood flow and disturbed fetal development in the rat.

Placental blood flow was measured with the aid of radioactive microspheres, in normal (N) and manifest diabetic (MD) rats, and related to fetal body growth and incidence of congenital malformations. The total blood flow in the placentae of the MD rats was decreased to about one-half of the normal flow on gestational days 20 and 22. The placentae of the MD offspring were enlarged, whereas the fetuses in this group were smaller than normal. Thus, the placental blood flow per placental weight was drastically decreased in the MD fetuses on both days 20 and 22. In contrast, the placental blood flow per fetal weight was not different in the N and MD groups on gestational day 20 whereas it was decreased in the MD offspring on gestational day 22. Placental blood flow in the malformed fetuses of the MD group did not differ significantly from that in the nonmalformed MD fetuses.

Animals↗
PubMed1984

The blood flow to the pancreas and the islets of Langerhans during an intraperitoneal glucose load in the rat.

The pancreatic blood flow (PBF) and the islet blood flow (IBF) of the rat have been calculated with the aid of the microsphere technique at various times after an intraperitoneal injection of 2 ml of a 30% glucose solution or of 0.9% saline. There was an increase in PBF at 5 min (p less than 0.05) and 25 min (p less than 0.05) after the administration of glucose as compared to the saline-injected animals. There was also a similar but more pronounced effect on the IBF with increases after 5 min (p less than 0.001), 15 min (p less than 0.01), and 25 min (p less than 0.05). Maximal glucose effects were found after 5 min with a peak value of 0.98 +/- 0.07 ml/min g pancreas for PBF (control value: 0.62 +/- 0.09 ml/min g pancreas) and 206 +/- 17 microliter/min X pancreas for IBF (control value: 65 +/- 10 microliter/min X pancreas). When expressed as a percentage of PBF the IBF was increased after 5 min (p less than 0.01) and 15 min (p less than 0.05) with a maximum of 14.4 +/- 1.5% (compared to 7.9 +/- 0.9% in the control animals) after 5 min. The data indicate a rapid and marked stimulatory effect of glucose on both PBF and IBF with a preferential effect on the latter. The mechanisms underlying this stimulation are unknown and may include both local intrapancreatic and extrapancreatic factors.

Animals↗
PubMed1984

Effect of propranolol and sclerotherapy in bleeding esophageal varices. A case report.

Portal hypertension and variceal bleeding are discussed in relation to the history of a patient with primary biliary cirrhosis. Beta-blockade and sclerotherapy failed to prevent recurrent bleeding and a shunt operation had to be done. In this patient the portal venous pressure increased despite continuous propranolol administration.

Combined Modality Therapy↗
PubMed1983

Stimulation by glucose of the blood flow to the pancreatic islets of the rat.

Blood flow to the pancreatic islets of the rat was estimated with the microsphere technique. Experiments with microspheres of different sizes (diameter 10, 15 or 50 micron) showed that optimal results were obtained with 10-micron spheres. Localization of microspheres either within or outside the islets was accomplished by freeze-thawing of the pancreas, making it transparent, so that both islets and microspheres could be distinguished in dark field illumination. Thus, microscopic examination of the freeze-thawed pancreas allowed the microspheres to be counted separately in both the endocrine and exocrine parenchyma. Under basal conditions, pancreatic blood flow was calculated as 0.60 ml X min-1 X g-1 (w/w). The islets accounted for about 10% of the total pancreatic blood flow, corresponding to 0.069 ml/min per whole pancreas. A bolus dose of glucose increased pancreatic blood flow to 0.75 ml X min-1 X g-1 (p less than 0.05), while the fractional islet blood flow rose to 15.1% (p less than 0.001) corresponding to 0.125 ml X min-1 X pancreas-1 (p less than 0.001). The glucose-induced increase in pancreatic blood flow mainly resulted from increased flow to the pancreatic tail, while the corresponding increase in islet blood flow was uniformly distributed throughout the pancreas. Injection of the non-metabolizable glucose-derivate. 3-0-methyl-D-glucose, affected neither the pancreatic nor the islet blood flow. The data indicate that the islets receive more of the pancreatic blood flow than would be accounted for by their relative volume and that glucose preferentially stimulates blood flow to the islets.

3-O-Methylglucose↗
PubMed1983

Tri-iodothyronine and thyroxine in human milk.

The concentration of tri-iodothyronine (T3) and thyroxine (T4) in human milk was determined by radioimmunoassay (RIA). The analysis of T3 was performed on unextracted milk and on ethanol extracts of defatted milk. Analysis of unextracted milk was complicated by artifacts. Reliable and reproducible results were achieved only with the milk extracts. In 10 colostral milk samples the mean T3 levels +/- SD were 0.80 +/- 0.52 nmol/l before feeding (early milk) and 0.93 +/- 0.62 after feeding (hind milk). The T3 concentration in colostrum did not change significantly during the feeding to the infant. In 12 mature milk samples collected between infant feedings, the mean T3 +/- SD was 1.19 +/- 0.42 nmol/l. T4 was not detected in any of the samples analysed (detection limit 3 nmol/l).

Colostrum↗
PubMed1983

Serum retinol and retinol-binding protein in mothers and infants at delivery.

The relations at birth between infant and maternal serum retinol, retinol-binding protein (RBP) and retinol/RBP molar ratio were investigated in 25 healthy term infants and their mothers. The mean serum levels of retinol and RBP were significantly higher in the mothers, but the mean molar ratio of retinol/RBP (RBP saturation) was significantly higher in the infants. Both the infant serum RBP and the infant RBP saturation were positively correlated to the respective serum levels in the mothers.

Female↗
PubMed1982

Post-partum release of prostaglandin F(2alpha) and uterine involution in the cow.

Peripheral plasma levels of the main blood plasma metabolite of PGF(2alpha) (15-keto-13,14-dihydro-PGF(2alpha)) and progesterone were investigated during the immediate, post-partum period in 59 normally calving cows. Uterine involution was monitored by weekly rectal palpations. The levels of the prostaglandin metabolite were high at parturition and remained thereafter elevated for periods varying up to 7-23 days. Uterine involution was completed during periods ranging from 16-53 days. According to the clinical findings, the animals were divided into three groups. Group A comprises 46 animals which had an uncomplicated, puerperal period. A significant (p<0.001) correlation between the duration of elevated prostaglandin levels and the time for completed uterine involution (Y=29.6 - 1.3 (X - 13.5)) was found for these animals. Group B animals (n=8) had periods of varying length with uterine discharge during the first 30 days post-partum. When compared to group A animals, the animals in group B had comparatively longer periods of prostaglandin release and also longer periods for completion of uterine involution. Group C animals (n=5) at times had palpable, thin-walled, cystlike structures in the ovaries during the first 30 days post-partum. In this group of animals, the periods of high prostaglandin levels, as well as for the completion of uterine involution, were similar to those for the animals in group A. Progesterone levels remained low during the immediate post-partum period and in no case were elevated levels found until the prostaglandin release had ceased.

Journal Article↗
PubMed1982

The influence of dietary factors on the vitamin E requirements of the low birthweight infant.

The vitamin E requirements for the low birthweight (LBW) infant varies with other dietary factors such as iron and polyunsaturated fatty acids (PUFA). This interaction is caused by the influence of iron on the oxidative breakdown of lipids (lipid peroxidation). Thus the need for fortification of infant formulas with vitamin E increases if the formulas are iron fortified or have a high content of PUFA. A vitamin E/linoleic acid ratio of greater than 1 IU/g is currently recommended. The formulas on sale in Sweden satisfies this recommendation. In breastmilk we found a vitamin E/linoleic acid ratio of greater than 1 IU/g in colostral and transitional milk. In mature breastmilk, however, 9 out of 24 samples showed a ratio less than 1 IU/g. Thus it is possible, that the LBW infant fed mature human milk may need a larger supplement of vitamin E than the formula fed infant.

Biotransformation↗
PubMed1982

Serum assays of netilmicin by enzyme multiplied immunoassay technique and bioassay: a comparative study.

Serum concentration determinations of netilmicin obtained with bioassay and the enzyme multiplied immunoassay technique were compared. There was no statistically significant difference between the precision of the two techniques (P greater than 0.05). When clinical serum was used, a systematic error was demonstrated between the enzyme multiplied immunoassay technique and bioassay.

Biological Assay↗