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Biomedical subjects

B Jacobsson

Publications and source records attributed to B Jacobsson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Intracellular metabolism of 3'-azidothymidine in isolated human peripheral blood mononuclear cells.

Azidothymidine (AZT) inhibits the replication of human immunodeficiency virus and it is the only drug so far licensed for treatment of acquired immunodeficiency syndrome (AIDS). A prerequisite for its antiviral activity is phosphorylation by cellular nucleoside kinases to the mono-, di-, and triphosphate levels. This study determined the capacity of isolated peripheral blood mononuclear cells (PBMC), resting or mitogen stimulated, from 36 different people of whom 5 were HIV+, to phosphorylate and accumulate intracellular AZT nucleotides. We found a large variation in the amount of products formed between PBMC treated at different times from the same individual as well as between the PBMC from different individuals. Resting PBMC showed the largest interindividual variation and their levels of AZT nucleotides were about 60-150-fold lower than in activated PBMC. The intracellular half lives of azidothymidine mono-, di-, and triphosphates, constituting, on the average, 96-99.2, 0.7-1.8, and 0.4-2.7% of total nucleotides at 0.08-1.6 microM AZT, respectively, were also determined. In mitogen-stimulated PBMC it was approximately 2.5 +/- 0.6 h for all the azidothymidine metabolites. The half-life for intracellular azidothymidine monophosphate in resting PBMC from two individuals was determined to 1.5 +/- 0.2 h. There appeared to be no significant difference in the AZT metabolism in PBMC from HIV-positive or-negative persons. A relative decrease in the intracellular formation of AZTDP and AZTTP from AZTMP was observed at concentrations of AZTMP above 1 microM. This fact may explain why lowering the doses of AZT still gives therapeutically efficient levels of the active metabolite AZTTP.

Adult↗
PubMed1991

Disc degeneration and associated abnormalities of the spine in elite gymnasts. A magnetic resonance imaging study.

The thoracolumbar spine was examined by magnetic resonance imaging (MRI) and the history of back pain was analyzed in 24 male elite gymnasts (age range, 19-29 years) and in 16 male nonathletes (age range, 23-36 years). Disc degeneration, defined as reduced disc signal intensity, was significantly more common in athletes (75%) than in nonathletes (31%). The gymnasts also had a higher incidence of other abnormalities of the thoracolumbar spine, and there was a significant correlation between reduced disc signal intensity and the other abnormalities among the gymnasts. There were also significant correlations between back pain and reduced disc signal intensity and abnormal vertebral configuration when the gymnasts run a high risk of developing severe abnormalities of the thoracolumbar spine, and they often have a history of back pain.

Adult↗
PubMed1991

Percutaneous nephrolithotomy through an intercostal approach.

During a 5-year period percutaneous nephrolithotripsy through an intercostal space was performed in 56 of 231 procedures. Minimal thoracic complications were seen in 3 of 53 patients with 11th intercostal space tracts into a lower, middle, or upper pole calyx. A working sheath and a pyelostomy drainage catheter were used in all these cases. Hydro- and pneumothorax requiring treatment occurred in 2 of 3 patients with a 10th intercostal space approach into an upper pole calyx combined with improper use of the working sheath and/or the pyelostomy catheter. Review of the literature also indicates that an intercostal approach appears safe when performed via the 11th intercostal space into a lower or middle pole calyx. Thoracic complications occurred when punctures were made towards an upper pole calyx or above the 11th rib. The complications may be limited by identifying the posterior inferior lung border by fluoroscopy during puncture, and performing it under general anesthesia with controlled breath-holding. The use of a working sheath to seal the pleural opening during the procedure and an efficient pyelostomy drainage catheter to allow free drainage of urine and to tamponade the tract postoperatively are also recommended.

Adult↗
PubMed1990

Primary double pigtail stenting as a treatment of upper urinary tract leaks.

During a 5-year period 21 consecutive patients with iatrogenic or traumatic upper urinary tract leaks (nonmalignant) underwent treatment 5 to 28 days later with an indwelling double pigtail stent via an antegrade or retrograde approach. Six patients underwent initial nephrostomy drainage for relief of obstruction causing decreased renal function and/or septicemia. Stent placement was successful in 20 patients and complete healing occurred within 2 to 7 weeks in all 20. At followup 2 to 32 months later (median 3 months) no stricture formation or deterioration of kidney function was noted. There were no major complications and 85% of the patients were able to leave the hospital without any form of external drainage within 1 week after stent placement.

Adult↗
PubMed1990

Back pain and radiologic changes in the thoraco-lumbar spine of athletes.

Back pain and radiological changes of the thoraco-lumbar spine were investigated in 142 top athletes, representing wrestling, gymnastics, soccer and tennis (age range 14-25 years). All groups of athletes reported back pain at high frequencies (50-85%). Male gymnasts had significantly increased incidence and severity of back pain as compared to the rest of the athletes. Radiological abnormalities occurred in 36-55% of the athletes. Reduced disc height, Schmorl's nodes and change of configuration of vertebral bodies correlated with back pain (P less than 0.05, P less than 0.01 and P less than 0.05). Significant covariation between these types of abnormalities was found. Athletes with great demands on the back are thus subjected to an increased risk of symptomatic damage of the spine.

Adolescent↗
PubMed1990

Transthyretin messenger ribonucleic acid expression in the pancreas and in endocrine tumors of the pancreas and gut.

Transthyretin (TTR) cDNA probes were used to determine the presence of TTR mRNA in Northern blots from rat, porcine, and human organs as well as from human endocrine tumors. We also used in vitro translation in our study of the human tissues. In accordance with previous findings, TTR mRNA was found in the choroid plexus and, to a lesser extent, in the liver of all three species. In addition low levels of TTR mRNA were identified in the rat and human pancreas. All of the endocrine pancreatic tumors (two glucagonomas, two insulinomas, and one nonfunctional tumor) and the gut carcinoid also contained TTR mRNA, whereas other endocrine tumors (two pheochromocytomas and one paraganglioma) and one adenocarcinoma of the pancreas were TTR mRNA negative. The level of TTR mRNA expression in most of the endocrine pancreatic tumors exceeded that in the liver. The in vitro translations produced pre-TTR molecules of similar size for all TTR mRNA-positive human organs and tumors.

Animals↗
PubMed1990

The significance of 'no significant difference'.

It is generally accepted that patients experience less discomfort with low osmolality contrast media (LOM) than with high osmolar media (HOM). Hard statistical facts from so called 'high quality' controlled trials, proving that more significant reactions such as vomiting, hives, urticaria or anaphylactic complications also are less common with LOM are, however, not readily available (3). One reason for this may be that most of the well designed controlled studies performed may have been tailored by the drug manufacturer for a specific purpose: to fulfil the format requirements for registration by the licensing governmental authorities. For this the sponsor, to save time, usually engages several medical centres, each only performing 15 to 60 studies (4). Materials of such a size are of course much too small to reveal any change in the frequency of a complication occurring with an incidence of only a few per cent or less. The absence of a statistically significant difference in such low incidences of complications does not justify any conclusion. The question then arises: how big a material would be needed to obtain a fair chance to statistically verify a clinically highly important decrease in the incidence of a complication from, for instance, 10 to 5 per cent? This paper deals with such questions.

Clinical Trials as Topic↗
PubMed1990

Radiologic abnormalities of the thoraco-lumbar spine in athletes.

A radiologic study of the thoraco-lumbar spine was performed in 143 (117 male and 26 female) athletes (wrestlers, gymnasts, soccer players and tennis players), aged 14 to 25 years and 30 male non-athletes, aged 19 to 25 years. Film interpretation was made after mixing the films from all groups and without knowledge of the individual's identity. Various types of radiologic abnormalities occurred in both athletes and non-athletes but were more common among athletes, especially male gymnasts and wrestlers. Abnormalities of the vertebral ring apophysis occurred exclusively in athletes. Combinations of different types of abnormalities were most common in male gymnasts and wrestlers.

Adolescent↗
PubMed1990

Risk exposure and incidence of injuries in school physical education at different activity levels.

Pupils in the age range of 14-19 years in the schools of a municipality in Sweden were observed prospectively for one year for acute injuries during school physical education (n = 2089). Pupils registered in the Injury Surveillance System for an acute injury sustained during physical education classes and treated by a physician were interviewed. The number of observed injuries was 53. The incidence rate as a ratio of injury and estimated time of activity has been calculated. Physical activity during leisure time was investigated by a mailed questionnaire to a random sample of 7% of the population in the same age range. Levels of physical activity during leisure time of the injured pupils were related to activity levels in the whole population. An increased risk of injury (7 times) was found in pupils with a low activity level, compared to those with a medium or high level, and the risk of injury in females with a sedentary life style was 10 times as high as in active females.

Adolescent↗
PubMed1989

In situ localization of transthyretin-mRNA in the adult human liver, choroid plexus and pancreatic islets and in endocrine tumours of the pancreas and gut.

In situ hybridization with 35S-labeled single stranded RNA probes was used on sections from formaldehyde-fixed and paraffin-embedded tissue specimens to provide semiquantitative data on the occurrence of transthyretin(TTR)-mRNA in human liver, choroid plexus and pancreatic islets as well as in 15 endocrine tumours of the pancreas and gut. A monoclonal antibody to TTR was used for immunocytochemical identification of the protein in consecutive sections. The amount of TTR-mRNA in hepatocytes was found to be much less than that in epithelial cells of the choroid plexus. Glucagon cells of the pancreatic islets were also specifically labeled and the level of TTR-mRNA in these cells was intermediate between that of hepatocytes and choroid plexus epithelial cells. Four glucagonomas, one malignant insulinoma and two midgut carcinoids were shown to contain TTR-mRNA. The 'in situ' labeled cells were also found to be TTR immunoreactive. These findings present the first conclusive evidence for TTR synthesis in pancreatic islets and in endocrine tumours. They also establish that the high serum concentration of TTR found in some patients with endocrine tumours (notably glucagonomas) is most likely due to tumour production of TTR.

Choroid Plexus↗
PubMed1989

Localization of transthyretin-mRNA and of immunoreactive transthyretin in the human fetus.

Five human fetuses at mid-term (16-20 weeks) and one with a gestational age of 8 weeks were investigated. The cellular localization of transthyretin (TTR)-mRNA in different organs was demonstrated by in situ hybridization with a 35S-labelled, single-stranded RNA probe. Immunoreactive TTR (TTR-IR) was localized with a monoclonal antibody to TTR. In all fetuses, choroid plexus epithelial cells demonstrated intense labelling for TTR-mRNA as well as strong TTR-IR. Hepatocytes, on the other hand, showed weak in situ labelling and weak or, in some cases, non-demonstrable TTR-IR. In all mid-term fetuses, but not in the 8 week fetus, TTR-mRNA and TTR were also expressed in pancreatic endocrine A-cells. The degree of in situ labelling in these A-cells was moderate, whereas that of TTR-IR was strong. Despite negative findings for TTR-mRNA in the gut and the kidney, endocrine cells of the gut and epithelial cells of the renal proximal convoluted tubules showed TTR-IR in some of the fetuses. The investigation provides evidence for TTR synthesis in the human fetal choroid plexus, liver and endocrine pancreas. However, further studies are required to demonstrate TTR synthesis in the gut and the kidney.

Fetus↗
PubMed1989

Effects of malnutrition on rat myocardial beta-adrenergic and muscarinic receptors.

Malnutrition, as well as malignancy, induces alterations in heart metabolism and performance. Previous studies have implicated adrenergic mechanisms as the cause. The present study was undertaken to investigate if the adenylate cyclase system in the rat heart was affected by malnutrition. Three different animal groups with malnutrition were compared with a control group: rats with acute starvation for 14-96 hours, rats with protein-calorie malnutrition for 2 weeks, and rats with tumors. Stimulation by beta-adrenergic receptors and inhibition by muscarinic receptors of adenylate cyclase activity were not altered by malnutrition. However, conditions used for in vitro adenylate cyclase determinations were, of necessity, not physiological. Neither did the number of beta-adrenergic and muscarinic receptors change. When competition-binding experiments were performed, differences comprising agonist affinity and affinity state distribution were noted among the groups. The myocardial beta-adrenergic receptors formed a reduced number of high-affinity sites in all groups as compared with the control rats. All high-affinity sites displayed a more than 10-fold increase in affinity toward isoproterenol and an impaired sensitivity to guanine nucleotides except in heart membranes derived from rats starved less than 48 hours. While the protein-calorie restricted and the tumor-bearing rats had myocardial beta-adrenergic receptors that were unresponsive to guanine nucleotides, after 48 hours of starvation the rats exhibited an attenuated guanine-nucleotide-induced affinity shift. No changes associated with malnutrition in myocardial membrane levels of the of the stimulatory guanine-nucleotide-binding protein were detected by cholera-toxin-induced ADP-ribosylation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1989

Transthyretin immunoreactivity in human and porcine liver, choroid plexus, and pancreatic islets.

We examined transthyretin immunoreactivity (TTR-IR) in human and porcine liver, choroid plexus, and pancreatic islets with both polyclonal and monoclonal antibodies to TTR. The specificity of the immunoreactions and the effects of various fixatives were tested in immunohistochemical and dot-blot systems. B-5 fixative (mercuric chloride and sodium acetate in formalin) was the best immunopreservative. In both species, the TTR-IR in choroid plexus epithelial cells was strong and was much greater than that in hepatocytes. Glucagon cells in pancreatic islets were also strongly TTR immunoreactive. Insulin cells were slightly TTR immunoreactive in human but strongly so in porcine pancreas. The finding of TTR-IR in normal islets explains the presence of TTR-IR in human endocrine pancreatic tumors, notably glucagonomas and malignant insulinomas.

Animals↗
PubMed1989

Voiding cystourethrography as a predictor of reflux nephropathy in children with urinary-tract infection.

Most children who develop renal damage (scarring) after urinary-tract infection have vesicoureteral reflux. Voiding cystourethrography is therefore usually recommended as the initial radiologic study in children with urinary-tract infection. However, renal damage may occur also in the absence of reflux. The aim of this investigation was to determine the sensitivity and predictive value of reflux during voiding cystourethrography in identifying children at risk for renal damage. Eighty-four consecutive children, 2 months to 6 years old, with nonobstructive, first-known, febrile urinary-tract infection underwent voiding cystourethrography and urography. Twenty-seven (32%) had reflux and 10 (12%) had or developed renal damage. Two of the children and four of the kidneys with renal damage had no reflux at initial examination. The sensitivity of reflux as a marker for renal damage was 80%, specificity was 74%, positive predictive value was 30%, and negative predictive value was 96%. Thus, most children who develop renal damage after urinary-tract infection have reflux during voiding cystourethrography. However, there is a risk, albeit small, for renal damage to occur in the absence of reflux.

Child↗