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Biomedical subjects

S Nilsson

Publications and source records attributed to S Nilsson.

At least 361 records · Page 20Linked to original sources
PubMed1986

Purification of hormone-sensitive lipase by high-performance ion exchange chromatography.

We have developed an improved method for purification of hormone-sensitive lipase from adipose tissue. The method employs two preparative high-performance ion-exchange chromatography steps on Mono Q and Mono S after detergent solubilization and partial fractionation of the enzyme by gradient sievorptive chromatography on QAE-Sephadex. About 0.2 mg of greater than 70% pure enzyme is prepared at 10% yield within 6-7 days from adipose tissue of 500 rats. This protocol is a major improvement over the previously established procedure in terms of accessibility, rapidity, enzyme purity, and yield.

Adipose Tissue↗
PubMed1986

Growth factors induce early pre-replicative changes in senescent human fibroblasts.

As human fibroblasts in culture senesce their response to platelet-derived growth factor (PDGF) becomes attenuated. To clarify at which level such cells are blocked in the pre-replicative part of the cell cycle, we have analysed PDGF-induced pre-replicative events in senescent (phase III) cultures. We found that phase III cells retain a normal number of PDGF receptors and that these are functional with regard to PDGF-induced receptor autophosphorylation. Phase III cells also respond to PDGF by rapid actin reorganization and increased levels of c-fos and c-myc mRNA, similar to growth-arrested phase II fibroblasts. However, the expression of the nuclear antigen K-67, which in phase II cell is induced in S-phase and continues to be expressed throughout the cell cycle, is not induced in phase III cells in response to PDGF. We conclude that phase III human fibroblasts, although blocked with regard to proliferation, still retain a functional growth factor receptor system, and display early responses when exposed to growth factors, such as changes in the cytoskeleton and the expression of proto-oncogenes.

Cell Division↗
PubMed1986

Long-term follow-up of children breast-fed by mothers using oral contraceptives.

In a long-term follow-up study 48 breast-fed children, whose mothers had used oral contraceptives containing 50 micrograms of ethinylestradiol while lactating, were compared to a matched control group whose mothers had not used any hormonal contraceptives during lactation. In spite of a very large number of data collected from several different sources of information, no effect could be demonstrated of the ingested steroid, neither upon the panorama of diseases nor upon intellectual or psychological behaviour of the infants and children up to 8 years of age. The mothers who used oral contraceptives lactated a significantly shorter period of time than the controls, but no differences were found in weight gain and height increase in the children between cases and controls.

Breast Feeding↗
PubMed1986

Autonomic nervous control of the circulatory system in the air-breathing fish Channa argus.

The control of the cardiovascular system with particular emphasis on the regulation of blood distribution in the gills and air-breathing organ was studied in the air-breathing teleost Channa argus. Perfused head preparations were used in addition to experiments with isolated strip preparations of arteries and heart chambers. The distribution of adrenergic nerves was investigated using Falck-Hillarp fluorescence histochemistry. This preliminary study shows an adrenergic control system composed of chromaffin cells and adrenergic nerves similar to that found in other teleosts investigated, although the systemic arteries (coeliac artery, dorsal aorta and the vasculature of the air-breathing organ) appear to lack an adrenergic innervation. The reactions of isolated artery strip preparations to acetylcholine and adrenaline resemble those seen in other teleosts, and there is a prominent inhibitory effect of L-isoprenaline suggestive of arterial beta-adrenoceptors. The general vascular resistance of the gill apparatus-air-breathing organ increases in response to acetylcholine or adrenaline, and there is a redistribution of perfusion flow from the air-breathing organ circuit (anterior venous outflow from the first and second pair of gills and the air-breathing organ) to the general systemic circuit (dorsal aortic outflow from the third and fourth pair of gills). Stimulation of the vagal branch entering the air-breathing organ mimics the effects of acetylcholine or adrenaline. This innervation is probably non-adrenergic since no adrenergic nerve fibres could be demonstrated in the vasculature of the air-breathing organ using the histochemical technique. An adrenergic control of the vasculature of the air-breathing organ is not likely, since the concentration of adrenaline needed to affect the vasculature is not reached in the plasma even during "stress".

Acetylcholine↗
PubMed1986

Microsurgical epididymovasostomy in the treatment of occlusive azoospermia.

In principle, azoospermia has two explanations: occlusion of the duct system and serious dysfunction of the testicular parenchyma. Some cases of duct occlusion are suitable for reconstructive surgery. The authors describe a reconstructive technique based on full mobilization of a single loop of the epididymal duct as caudally as possible with two-layer side-to-end anastomosis to the vas deferens. To ensure follow-up evaluation of each anastomosis, unilateral anastomosis was done primarily. In a few cases, cross-over anastomosis was necessary. In cases of reoperation, if possible, this was performed on the same side. When the epididymal duct system was found empty, the contralateral epididymis was explored. Patients with postoperative oligozoospermia were offered a supplementary contralateral operation. From 1980 to 1984, 41 patients underwent epididymovasostomy. At follow-up evaluation, 35 (85%) presented sperms in repeated tests. Fifteen of these patients (37%) have fathered children. Patients with postoperative normospermia and no antisperm antibodies had an excellent fertility prognosis. The single-loop dissection technique provides anatomic specificity and a high percentage of patent anastomoses and does not interfere with the possibilities of reoperation.

Adult↗
PubMed1986

A double-blind, multicenter immunotherapy trial in children, using a purified and standardized Cladosporium herbarum preparation. I. Clinical results.

A double-blind histamine placebo controlled immunotherapy trial was performed to investigate the clinical effect of a purified and standardized Cladosporium herbarum allergen preparation. Thirty children with a clinical history suggesting mould-induced asthma and/or rhinoconjunctivitis were included. The diagnosis was confirmed by positive skin prick test and Phadebas RAST as well as positive bronchial and/or conjunctival provocation test to Cladosporium herbarum. Immunotherapy was given for 10 months in a double-blind manner to randomized groups with either Pharmalgen/Cladosporium herbarum preparation or histamine placebo. Allergic side effects to injections were common, especially during the peak of the mould season (July-September in Scandinavia). In the active group, 13/16 patients experienced general reactions during the first 10 months of treatment. After 6 months of treatment, eye, nose and bronchial symptom scores and peak expiratory flow rates were similar for the groups, maybe because most of the children were also sensitive to many other allergens, including Alternaria alternata. However, medication scores were significantly lower in the treated group (P less than 0.01). Bronchial (P less than 0.01) and conjunctival sensitivity (P = 0.01) were significantly reduced in the Cladosporium-treated group but not in the placebo group after 10 months of treatment. This is the first double-blind clinical trial showing the clinical efficacy of immunotherapy in children with mould-induced asthma.

Adolescent↗
PubMed1986

Influence of intrapelvic pressure on excretion of sodium from human hydronephrotic kidneys.

The influence on urinary excretion of sodium (NNa . V) of intrapelvic pressure, urinary flow, and mean arterial blood pressure during forced diuresis was evaluated in 12 patients with unilateral hydronephrosis. Total and divided renal functions were measured using 51Cr-EDTA clearance and isotope renography. The amount of sodium, excreted by the obstructed kidney, decreased with higher maximum intrapelvic pressure and increased with higher differences between the mean arterial blood pressure and maximum intrapelvic pressure. The higher the concentrating ability, the lower the amount of sodium excreted by the obstructed kidney. There was a highly significant negative correlation between maximum intrapelvic pressure and urinary flow, but no correlation between mean arterial blood pressure and maximum intrapelvic pressure. Thus, obstructed kidneys with normal concentrating ability have the same excretion of sodium as the nonobstructed contralateral kidney during forced diuresis. Obstructed kidneys with decreased concentrating ability on the other hand excrete comparatively more sodium. This is probably due to a defect in sodium resorption.

Adult↗
PubMed1986

Blood pressure control during exercise in the Atlantic cod, Gadus morhua.

Atlantic cod were subjected to 12-15 min swimming exercise at 2/3 body lengths s-1 in a Blazka-type swim tunnel. Pre- and postbranchial blood pressures, cardiac output (ventral aortic blood flow) and heart rate were continuously recorded, and blood samples for measurement of arterial and mixed venous oxygen tension were taken before and at the end of the exercise period. In a second group of fish, subjected to similar exercise regimes, blood samples were taken for analysis of the plasma concentrations of catecholamines. Pre- and postbranchial blood pressures and cardiac output increase during exercise, while the mixed venous oxygen tension decreases. The effect on cardiac output is due to an increase of both heart rate and stroke volume. There are no significant changes in either systemic or branchial vascular resistances, or in the plasma concentrations of catecholamines. Injection of the adrenergic neurone-blocking drug bretylium produces a decrease in postbranchial blood pressure in resting cod, due to a decrease in the systemic vascular resistance. Exercising cod treated with bretylium have a significantly lower pre- and postbranchial blood pressure than exercising control cod. This is due mainly to a dramatic reduction in the systemic vascular resistance. The alpha-adrenoceptor antagonist phentolamine does not further affect the blood pressure in cod treated with bretylium. It is concluded that the exercise hypertension observed in cod depends on the effect of adrenergic vasomotor fibres maintaining the systemic vascular resistance, and also on the increase in cardiac output. An adrenergic innervation of the heart may play some role in the control of cardiac performance both at rest and during exercise, but the main cardioregulatory mechanism is likely to be non-adrenergic, most probably including cardiac control via variation of the cholinergic vagal cardioinhibitory tonus.

Animals↗
PubMed1986

Smoking and cervical intraepithelial neoplasia. An association independent of sexual and other risk factors?

The connection between smoking and cervical neoplasia has been questioned. The association demonstrated has been suspected to depend on a correlation between smoking and sexual behavior or other risk factors for cervical neoplasia. This case-control study included 140 women with cervical intraepithelial neoplasia diagnosed during pregnancy. For each case, 2 healthy, age-matched women, who simultaneously attended for a pregnancy check at the same maternity clinic, served as controls. Information was obtained on obstetrical and gynecological history, sexual behavior, contraceptive methods, female and male smoking habits and socioeconomic status, using both an interview and a questionnaire. The patients were significantly younger at first intercourse and first pregnancy, had more sexual partners, showed a higher frequency of both female and male smokers and had a different pattern of contraceptive use vis-á-vis the controls. Analyses of covariance were used to identify and check for possible confounding before a log-linear regression analysis was ultimately carried out. Two factors remained closely associated with cervical intraepithelial neoplasia: number of sexual partners, and female smoking. We conclude that smoking seems to be a genuine risk factor for cervical intraepithelial neoplasia.

Adolescent↗
PubMed1985

Turnover of tissue plasminogen activator in normal and hepatectomized rabbits.

The distribution, and clearance of the tissue plasminogen activator (tPA) was studied in rabbits, rats and mice. Following an intravenous injection of I-labelled tPA a large portion of the radioactive dose was rapidly accumulated in the liver. After one hour the radioactivity in the liver was less than 5 per cent of the injected dose. The highest activity was then found in the intestine, stomach and in the blood. Gel filtration of plasma taken one hour after the injection revealed that the major part (60%) of the radioactivity was present as low molecular weight metabolites or free iodine. The remaining activity was present as high molecular weight inhibitor complexes (26%) or as free tPA (15%). In order to study in vivo reactions between tPA and plasma inhibitors without hepatic interference, plasma turnover was also studied in hepatectomized rabbits. High amounts of radioactivity remained in the plasma after one hour. Gel filtration of this plasma revealed that 54 per cent of the radioactivity was bound to inhibitors, 34 per cent circulated as free tPA while a minor portion (12%) was found as free iodine or metabolites. The half-life of fibrinolytically active tPA in hepatectomized rabbits was 40 minutes compared to 2 minutes in intact rabbits. The increase in the half-life of tPA in hepatectomized rabbits also resulted in an improved thrombolytic effect after treatment with 0.5 mg tPA.

Animals↗
PubMed1985

Neuropeptides in the gastrointestinal canal of Necturus maculosus. Distribution and effects on motility.

The presence and distribution of regulatory peptides in nerves and endocrine cells of the stomach, intestine and rectum of a urodele amphibian, the mudpuppy, Necturus maculosus, was studied immunohistochemically in sections or whole-mount preparations of the gut wall. The effect of the occurring peptides on gut motility was studied in isolated strip preparations of circular and longitudinal smooth muscle from different parts of the gut. Bombesin-, neurotensin-, substance P- and VIP-like immunoreactivity was present in abundant nerve fibres in the myenteric plexus of both stomach, intestine and rectum. Single fibres or bundles were present in the circular muscle layer and in a well-developed deep muscular plexus in the intestine and rectum. Immunoreactive nerve cells were found in the myenteric plexus of the stomach, intestine (neurotensin only) and rectum. Gastrin/CCK-like immunoreactivity was observed only in a few fibres in stomach and rectum. Endocrine cells containing bombesin-, met-enkephalin-, gastrin/CCK-, neurotensin-, somatostatin- or substance P- like immunoreactivity were present in the mucosa. The effect of bombesin was an inhibition of the rhythmic activity in circular muscle preparations and in longitudinal muscle from the rectum, while longitudinal muscle from the stomach usually responded with a weak increase in tonus. Neurotensin, like-bombesin, was inhibitory on the spontaneous rhythmic activity of circular muscle throughout the gut, while the effect on longitudinal muscle was an increase in tonus. Met-enkephalin and substance P increased the tonus of all types of preparations, and often, in addition, initiated a rhythmic activity superimposed on this maintained tonus. VIP had a general inhibitory effect on the preparations, decreasing tonus and/or abolishing rhythmic activity. It is concluded that bombesin-, neurotensin-, substance P- and VIP-like peptides are present in nerves throughout the urodele gut and may have physiological functions in regulating the motility of the gut. The gastrin/CCK-like peptide present in nerves of the stomach and rectum may affect the function of these parts of the gut. The regulatory peptides present in endocrine cells may, perhaps with the exception of the somatostatin-like peptide, affect the motility humorally.

Animals↗
PubMed1985

Studies on urinary bladder carcinoma by morphometry, flow cytometry, and light microscopic malignancy grading with special reference to grade II tumours.

Biopsies from 28 patients with urinary bladder carcinoma were investigated by flow cytometry and morphometry. Histopathological grading on 1.5 microns thick glycol methacrylate sections was also performed. Nuclear profile areas, nuclear volume densities and mitotic indices were usually larger in the higher grades of malignancy. All grade I tumours were diploid and all grade III tumours were aneuploid. Out of 13 grade II tumours 8 were diploid and 5 aneuploid. In these latter five cases nuclear profile areas were at the high end of the spectrum. The data show that flow cytometry and morphometry could be a valuable tool in the diagnosis of urinary bladder carcinoma. Our data also suggest that a subdivision of the grade II tumours might be possible and meaningful in the assessment of prognosis.

Adult↗