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Biomedical subjects

K Andersson

Publications and source records attributed to K Andersson.

At least 127 records · Page 7Linked to original sources
PubMed1997

DNA analysis indicates patient-specific human papillomavirus type 16 strains in Bowen's disease on fingers and in archival samples from genital dysplasia.

Human papillomavirus (HPV) type 16 is casually involved in the pathogenesis of anogenital cancer and has also been demonstrated in some patients with Bowen's disease (BD) on the fingers. From two women with HPV 16 in BD on the fingers, and in archival samples from genital dysplasia, collected as long as 26 years ago, the non-coding region of the virus was amplified by the polymerase chain reaction and sequenced. The HPV 16 DNA sequences found in the finger lesions and in the genital archival samples showed no diversities within single patients. Compared with an HPV 16R reference sequence, one patient showed a unique T nucleotide at position 78, whereas the other patient exhibited T and A nucleotides at positions 7193 and 7521, respectively. In one of the patients, the same strain of HPV 16 was found in a digital tumour 26 years after its clearance from the genital tract. DNA sequence analysis indicated patient-specific HPV 16 strains. Auto-inoculation from the genital tract was favoured as a plausible explanation of why HPV 16 caused BD on the fingers.

Adult↗
PubMed1996

Gastrin-evoked secretion of pancreastatin and histamine from ECL cells and of acid from parietal cells in isolated, vascularly perfused rat stomach. Effects of isobutyl methylxanthin and alpha-fluoromethylhistidine.

The ECL cells in the rat stomach release pancreastatin and histamine in response to gastrin stimulation. The present study compares the release of pancreastatin and histamine from the ECL cells and the secretion of acid from the parietal cells in response to gastrin, and examines how a markedly reduced histamine content in the ECL cells will affect the gastrin-evoked release of pancreastatin and the secretion of gastrin acid. Totally isolated, vascularly perfused stomachs were prepared from fasted rats. Some of the rats had been pre-treated for 24 h with (alpha-fluoromethylhistidine (alpha-FMH), resulting in 80% depletion of oxyntic mucosal histamine (mainly ECL-cell histamine). The stomachs were perfused with rat gastrin-17, alpha-FMH, isobutyl methylxanthine (IBMX), or vehicle in various combinations for 8 h. The venous outflow was collected (30-min samples) for determination of histamine and pancreastatin-like immunoreactivity (LI) and the gastric luminal outflow was collected for determination of H+. Gastrin raised the outflow of pancreastatin-LI and histamine but did not raise the acid output unless IBMX was added. The outflow of pancreastatin-LI and histamine was greater after gastrin + IBMX (at least during the first 4-h period) than after gastrin alone. alpha-FMH reduced gastrin-evoked histamine outflow but did not affect gastrin-evoked pancreastatin-LI outflow. Also the acid output in response to gastrin + IBMX was much reduced by alpha-FMH. In conclusion, increased levels of intracellular cAMP enhanced the gastrin-evoked release of pancreastatin-LI and histamine from the ECL cells and made it possible for histamine, released from the ECL cells, to cause acid secretion from the parietal cells. ECL-cell histamine depletion reduced the gastrin-evoked acid secretion; it did not affect the gastrin-evoked release of pancreastatin-LI.

1-Methyl-3-isobutylxanthine↗
PubMed1996

[Glucagonoma. A tumor disease with multiple clinical manifestations].

Glucagon-producing neoplasms are rare pancreatic tumours that may give rise to a characteristic syndrome including, diabetes and typical skin manifestations (necrolytic migrating erythema). Dermatological problems are often the first signs of the disease and the diagnosis is easily overlooked. In most series reported to date, glucagonomas had already metastasized at diagnosis, which means that curative surgery was possible to perform in less than half of the patients. To increase awareness of glucagonoma symptomatology a review of the syndrome is presented together with the clinical histories of three patients, recently treated. These cases illustrate aspects of modern diagnosis and treatment.

Adult↗
PubMed1996

Reference spirometric values in healthy Nicaraguan male workers.

The main objective was to derive reference equations for the FVC, FEV1, and FEV1/FVC ratio for healthy Nicaraguan male workers without current occupational exposure to agents hazardous to the lungs. Age, height, and weight were included as independent variables in the analysis, but only age and height showed significant effects on the indices studied. A nonlinear relationship with age was observed for FVC and FEV1, with a shift in the slope at the age of 32 years. Linear, quadratic, and multiphase models were tested in order to assess the best reference equation. The multi-phase model most closely fitted the values measured. The FEV1/FVC ratio showed a significant linear negative correlation with age. A comparison between the equations derived from this material and those reported in other studies revealed substantial differences. Racial, genetic, nutritional, work and sociocultural factors could account for the differences.

Adolescent↗
PubMed1996

Elevated potassium enhances glutamate vulnerability of dopaminergic neurons developing in mesencephalic cell cultures.

This study examines the effects of high K+ concentration on the growth and development of mesencephalic cells and their glutamate vulnerability. Mesencephalic cell cultures obtained from Wistar rat embryos on the 14th gestational day were maintained for 14 days in medium with either normal (4.2 mM) or elevated (24.2 mM) potassium concentration. There was no significant difference due to various K+ concentration in cell growth and survival up to day in vitro (DIV) 13-14. In order to test the glutamate (Glu) vulnerability, cultures were treated with 100 mu M Glu for 15 min in salt solution on the DIV 3,6,8 and 13. Glu-induced neuronal damage was estimated 24 h later by measuring the neuron-specific enolase (NSE) content in the culture medium and by counting the number of tyrosine hydroxylase-immunoreactive (TH-IR) neurons. Glu had no damaging effect on the cells on DIV 3, but became pronounced beyond DIV 6. Elevated potassium concentration 24.2 mM) in the culture medium during development significantly increased neuronal vulnerability to Glu treatment, indicated by a higher increase of NSE content in the medium and by a more pronounced Glu-induced decrease of the number of TH-IR cells. The Glu-induced decrease of the number of TH-IR cells and of NSE-IR cells let us conclude that dopaminergic neurons are more vulnerable to glutamate than other neurons from mesencephalic culture.

Animals↗
PubMed1996

Effects of perinatal asphyxia on the mesostriatal/mesolimbic dopamine system of neonatal and 4-week-old male rats.

The present study was undertaken in order to study the effects of perinatal asphyxia on tyrosine hydroxylase (TH) activity, dopamine levels and turnover, and dopamine metabolites (3,4-dihydroxyphenylacetic acid, DOPAC, homovanillic acid, HVA, and 3-methoxytyramine, 3-MT, analyzed by high-performance liquid chromatography, HPLC) measured in the basal ganglia of the 20- to 40-min-old newborn and 4-week-old male rat. Asphyxia was induced in pups by placing the fetuses, still in their uterus horns removed by hysterectomy from pregnant rats at full term, in a 37 degrees C water bath for 15-16 min or 19-20 min. Following asphyxia, the uterus horns were opened, and the pups were removed and stimulated to breathe. A 100% and 50-80% pup survival was obtained following 15-16 min and 19-20 min of asphyxia, respectively. Acute changes were studied in brains from newborn pups 20-40 min after delivery, and long-term changes were studied in brains from 4-week-old rats. No changes in TH-activity could be observed in the substantia nigra/ventral tegmental area (SN/VTA), the striatum, or the accumbens nucleus/olfactory tubercle (ACC/TUB), in the newborn or the 4-week-old rat. In the newborn rat, 19-20 min of asphyxia increased (as compared to controls) dopamine levels in the SN/VTA to 136 +/- 14% and in the ACC/TUB to 160 +/- 10%, indicating an increased synthesis and/or release of dopamine. DO-PAC levels were increased in the SN/VTA to 150 +/- 14% and in the ACC/TUB to 151 +/- 10%, and HVA levels were increased to 152 +/- 16% in the striatum and to 117 +/- 4% in the ACC/TUB. Following 15-16 min of asphyxia, dopamine levels were increased to 130 +/- 12% in the ACC/TUB, and DOPAC levels were increased to 135 +/- 6% and 130 +/- 12% in the SN/VTA and the ACC/TUB, respectively. This suggests that the increased dopamine levels may preferably reflect an increased release of dopamine following perinatal asphyxia. In the 4-week-old rat, dopamine levels were decreased in the SN/VTA to 71 +/- 4%, in the striatum to 52 +/- 8%, and in the ACC/TUB to 53 +/- 7%, following 19-20 min of perinatal asphyxia as compared to controls. No changes were observed in DOPAC, HVA, or 3-MT levels, indicating that the reduced dopamine levels reflect a reduced dopamine synthesis following perinatal asphyxia. A decrease in dopamine utilization was observed in the striatum to 15 +/- 8% and in the ACC/TUB to 9 +/- 13% following 19-20 min of perinatal asphyxia as compared to controls. This indicates that perinatal asphyxia produced long-lasting reductions in activity in the mesostriatal/mesolimbic dopamine systems in the 4-week-old rat.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Ultrastructure of enterochromaffin-like cells in rat stomach: effects of alpha-fluoromethylhistidine-evoked histamine depletion and hypergastrinemia.

Histamine-producing enterochromaffin-like (ECL) cells are numerous in the oxyntic mucosa of the rat stomach. They respond to gastrin by secretory activation, hypertrophy and hyperplasia. They contain cytoplasmic granules (median profile diameter 120 nm), secretory vesicles (180 nm) and microvesicles (70 nm). alpha-Fluoromethylhistidine (alpha-FMH) depletes histamine from the ECL cells by inhibiting the histamine-forming enzyme histidine decarboxylase. Long-term hypergastrinemia, evoked by omeprazole, increases the ECL-cell histamine concentration. The way in which chronic histamine depletion affects omeprazole-induced ECL-cell hypertrophy, and the ways in which granules and vesicles in the ECL cells respond to alpha-FMH and/or omeprazole have been studied. Rats were treated with alpha-FMH (3 mg/kg per h subcutaneously), omeprazole (400 micromol/kg per day orally), alpha-FMH+omeprazole, or vehicle for 6 weeks. ECL cell profiles in electron micrographs were analysed panimetrically. The results show that the omeprazole-evoked hypertrophy of the ECL cells is not affected by depletion of ECL-cell histamine, thereby supporting the view that ECL-cell histamine is not important for full expression of the gastrin-evoked trophic effects on the ECL cells. The loss of ECL-cell histamine following treatment with alpha-FMH and with alpha-FMH+omeprazole is associated with a greatly reduced size of the secretory vesicle compartment. The granules, on the other hand, are unaffected by alpha-FMH and alpha-FMH+omeprazole. Omeprazole treatment leads to the appearance of numerous vacuoles (with profile diameter greater than 500 nm); such vacuoles are not observed in the ECL cells of rats treated with alpha-FMH or alpha-FMH+omeprazole. The omeprazole-induced increase in ECL-cell histamine is associated with an increase in the compartment composed of secretory vesicles and vacuoles. The findings support the hypothesis that secretory vesicles (and vacuoles) represent a major storage site of ECL-cell histamine.

Animals↗
PubMed1996

Effect of alpha-fluoromethylhistidine-evoked histamine depletion on ultrastructure of endocrine cells in acid-producing mucosa of stomach in mouse, rat and hamster.

The oxyntic mucosa of the mammalian stomach is rich in endocrine cells, such as ECL cells, A-like cells, somatostatin cells, D1/P cells and, in some species, enterochromaffin cells. The various endocrine cell types can be distinguished on the basis of their characteristic cytoplasmic granules and vesicles. The ECL cells contain numerous large secretory vesicles and relatively few, small electron-dense granules and small clear microvesicles. We have suggested that in the rat the ECL cells contain most of the gastric histamine with the secretory vesicles as the major histamine storage site in these cells. alpha-Fluoromethylhistidine is an irreversible inhibitor of histidine decarboxylase, the histamine-forming enzyme. We have previously shown that this enzyme inhibitor depletes histamine from the ECL cells in the rat and reduces the number of secretory vesicles in the cytoplasm. In the present study, we have examined whether alpha-fluoromethylhistidine affects the ECL cells in other species and whether it affects other types of endocrine cells in the oxyntic mucosa of the rat. Mice, rats and hamsters were treated with the inhibitor (3 mg/kg per h) via minipumps subcutaneously for 24 h. This treatment lowered the oxyntic mucosal histamine concentration by 65-90% and the number and volume density of the secretory vesicles by 85-95% in the ECL cells of the three species examined. In contrast, the number and volume density of granules and microvesicles were not greatly affected. No evidence was found for an effect of alpha-fluoromethylhistidine on A-like cells, somatostatin cells or D1/P cells of the rat stomach, suggesting that, unlike the ECL cells, they do not contain histamine.

Acids↗
PubMed1996

The effects of lesions in the mesencephalic raphe systems on male rat sexual behavior and locomotor activity.

Lesions were produced in the median and the dorsal raphe nuclei of the rat, and the effects of these injuries on various behaviors were studied. The median raphe lesions had facilitatory effects on the male rat sexual behavior, as evidenced by a decrease in the number of intromissions prior to ejaculation, as well as shortening of the ejaculation latency and the postejaculatory interval. No effects were seen on the masculine sexual behavior after lesions in the dorsal raphe nucleus. The median raphe lesions drastically increased the locomotory activity whereas the dorsal raphe lesions did not. Treatment with FG5893, a 5-HT1A agonist/5-HT2A receptor antagonist, increased the locomotor activity of the dorsal-raphe-lesioned rats but did not affect the median-raphe-lesioned animals. These results suggest that the dorsal and the median raphe nuclei play different roles in the neural regulation of the sexual behavior and locomotor activity of the male rat. The median raphe nucleus appears to exert a modulatory influence upon these behaviors, which probably is mediated by serotonergic neural pathways.

Animals↗
PubMed1996

Chronic continuous infusion of (-)nicotine reduces basic fibroblast growth factor messenger RNA levels in the ventral midbrain of the intact but not of the 6-hydroxydopamine-lesioned rat.

A negative correlation has been found between smoking and Parkinson's disease. There is evidence to suggest that this correlation appears to be associated with a neuroprotective role of nicotine for dopamine neurons at least in relation to mechanical injury. However, 1-methyl-4-phenyl-1,2,3,6,-tetrahydropyridine (MPTP) neurotoxicity to dopamine neurons is enhanced by chronic continuous (-)nicotine. More recently, basic fibroblast growth factor has been found to possess neurotrophic activities for many nerve cells including the dopamine cells in vivo and in vitro. Therefore, it is of interest to explore a possible effect of nicotine on basic fibroblast growth factor expression in the ventral midbrain of intact and 6-hydroxydopamine-lesioned rats and how treatment with nicotine can alter the 6-hydroxydopamine-induced injury of the nigral dopamine nerve cells as evaluated by dopamine biochemistry. In the present paper, an analysis of the effects of chronic continuous infusion of (-)nicotine via minipumps was carried out on basic fibroblast growth factor expression in the vental midbrain of the intact male rat and of the 6-hydroxydopamine lesioned rat. A quantitative messenger RNA protection assay analysis was used as well as an immunocytochemical analysis in the substantia nigra. Our findings give evidence that a two-week continuous infusion with (-)nicotine in the intact rat leads to substantial and dose-related (0.03-0.3 mg/kg per h) reductions of basic fibroblast growth factor messenger RNA levels in the ventral midbrain. These changes are not associated with changes in neuronal and glial basic fibroblast growth factor immunoreactivity in this region with the antibodies used. However, a one-week continuous infusion with (-)nicotine (0.125 mg/kg per h) failed to significantly alter the basic fibroblast growth factor messenger RNA levels in the ventral midbrain of solvent and 6-hydroxydopamine-injected rats and thus also the 6-hydroxydopamine-induced increase of basic fibroblast growth factor messenger RNA levels in the ventral midbrain of the lesioned side observed at this time-interval and known to be of astroglial origin [Chadi G. et al. (1994) Neuroscience 61, 891-910]. In agreement, the 6-hydroxydopamine-induced depletion of dopamine in the neostriatum was unaltered by the nicotine treatment (0.125 mg/kg per h). Thus, chronic continuous (-)nicotine treatment may lead to a reduced basic fibroblast growth factor trophic tone in the ventral midbrain of the intact but not of the 6-hydroxydopamine-lesioned rat neither on the lesioned nor on the unlesioned side of the ventral midbrain. It seems possible that chronic nicotine treatment mainly reduces basic fibroblast growth factor messenger RNA levels of neuronal origin, since the astroglial messenger RNA levels dominate after the 6-hydroxydopamine-induced lesions.

Animals↗
PubMed1996

Decrease in muscle glutamine, ribosomes, and the nitrogen losses are similar after laparoscopic compared with open cholecystectomy during the immediate postoperative period.

BACKGROUND: The purpose of the study was to compare the postoperative muscle amino acid pattern, the ribosome concentration and size distribution, and postoperative nitrogen balance in patients who underwent either laparoscopic or open cholecystectomy. METHODS: Patients who underwent cholecystectomy by means of either laparoscopy (n=8;LAP) or laparotomy (n=8;OPEN) were studied. The concentrations of amino acids, ribosomes, and polyribosomes, reflecting protein synthesis, were determined in skeletal muscle tissue before operation and on postoperative day 2. The cumulated nitrogen balance was determined. RESULTS. Decreases in muscle glutamine (26.7% +/- 8.4% in the LAP group and 30.3% and +/- 4.5% in the OPEN group) and in polyribosomes (28.7% +/- 6.5% in the LAP group and 23.6% +/- 8.5% in the OPEN group) were observed without differences between the groups (mean +/- SEM). The nitrogen losses were similar in both groups (15.2 +/-1.6 gm in the LAP group and 15.5 +/- 1.2 gm in the OPEN group). CONCLUSION: A stress++ response with effects on amino acid and protein metabolism in muscle in present also after laparoscopic cholecystectomy. On postoperative day 2 this response is of similar magnitude after both the laparoscopic and the open procedures.

Adult↗
PubMed1996

Effect of a short-term infusion of glutamine on muscle protein metabolism postoperatively.

The acute effect of a short-term postoperative infusion of glucose supplemented with glutamine (0.285 g/kg body weight), on muscle protein metabolism, was studied by analyses of free amino acid concentrations and determinations of protein synthesis. A glutamine-glucose infusion was given for 5.5 h to 6 patients 2-3 days after elective surgery for colon cancer. The free glutamine concentration was 5.72 +/- 0.96 mmol/kg wet weight (ww) before and 6.14 +/- 1.10 mmol/kg ww 4 h after the glutamine infusion. The rate of protein synthesis was 1.26 +/- 0.15%/24 h before the infusion and 1.12 +/- 0.16%/24 h during its latter part. The percentage of polyribosomes was 42.2 +/- 3.4% before and 40.9 +/- 1.3% after the infusion. The results showed no difference in these biochemical parameters, indicating that a short-term infusion of glutamine given postoperatively is insufficient to affect protein metabolism in human skeletal muscle.

Journal Article↗
PubMed1996

Effect of nicotine infusion in humans on platelet aggregation and urinary excretion of a major thromboxane metabolite.

The objective of this study was to evaluate further a possible role of nicotine as a stimulator of platelet aggregability and platelet arachidonic acid metabolism in vivo. In six healthy, non-smoking males, platelet aggregability was assessed by filtragometry and impedance aggregometry before, during and after an intravenous infusion of nicotine at two different doses (0.25 and 0.5 microgram kg-1 min-1) for 30 min. The aggregatory response was also measured after the addition of nicotine at final concentrations ranging from 10(-11) mol L-1 directly to the aggregating blood. The synthesis of thromboxane A2 (TxA2) in platelets was estimated by quantitating the urinary excretion of 2.3-dinor-thromboxane B2 (Tx-M). Despite the plasma concentrations of nicotine, cotinine and catecholamines in the range of those occurring during acute cigarette exposure, the excretion of Tx-M (204 +/- 36 pg mg-1 creatinine) remained unaltered during nicotine infusion. Similarly, platelet aggregatory response to collagen was not influenced by nicotine when infused or added in vitro. However, an enhanced aggregability was detected by filtragometry during the infusion of nicotine at the higher dose employed. The results indicate that nicotine, infused at moderate doses, produces a weak platelet stimulation that is not accompanied by significant release of thromboxane A2, as monitored by urinary excretion of Tx-M. Although a direct action of nicotine on platelets cannot be excluded, it appears more likely that the enhancement of platelet function is mediated by other, secondary mechanisms.

Adult↗
PubMed1996

On the origin of extracellular glutamate levels monitored in the basal ganglia of the rat by in vivo microdialysis.

Several putative neurotransmitters and metabolites were monitored simultaneously in the extracellular space of neostriatum, substantia nigra, and cortex and in subcutaneous tissue of the rat by in vivo microdialysis. Glutamate (Glu) and aspartate (Asp) were at submicromolar and gamma-aminobutyric acid (GABA) was at nanomolar concentrations in all brain regions. The highest concentration of dopamine (DA) was in the neostriatum. Dynorphin B (Dyn B) was in the picomolar range in all brain regions. Although no GABA, DA, or Dyn B could be detected in subcutaneous tissue, Glu and Asp levels were 5 and approximately 5 and approximately 0.4 microM, respectively. Lactate and pyruvate concentrations were approximately 200 and approximately 10 microM in all regions. The following criteria were applied to ascertain the neuronal origin of substances quantified by microdialysis: sensitivity to (a) K+ depolarization, (b) Na+ channel blockade, (c) removal of extracellular Ca2+, and (d) depletion of presynaptic vesicles by local administration of alpha-latrotoxin. DA, Dyn B, and GABA largely satisfied all these criteria. In contrast, Glu and Asp levels were not greatly affected by K+ depolarization and were increased by perfusing with tetrodotoxin or with Ca2+-free medium, arguing against a neuronal origin. However, Glu and Asp, as well as DA and GABA, levels were decreased under both basal and K+-depolarizing conditions by alpha-latrotoxin. Because the effect of K+ depolarization on Glu and Asp could be masked by reuptake into nerve terminals and glial cells, the reuptake blocker dihydrokainic acid (DHKA) or L-trans-pyrrolidine-2,4-dicarboxylic acid (PDC) was included in the microdialysis perfusion medium. The effect of K+ depolarization on Glu and Asp levels was increased by DHKA, but GABA levels were also affected. In contrast, PDC increased only Glu levels. It is concluded that there is pool of releasable Glu and Asp in the rat brain. However, extracellular levels of amino acids monitored by in vivo microdialysis reflect the balance between neuronal release and reuptake into surrounding nerve terminals and glial elements.

Amino Acids↗
PubMed1996

Skeletal muscle glutathione after surgical trauma.

OBJECTIVE: The authors investigate the effect of surgical trauma on skeletal muscle concentrations of glutathione in patients undergoing selective abdominal surgery. SUMMARY BACKGROUND DATA: The posttraumatic state is accompanied by characteristic changes in the pattern of free amino acids and a decline of protein synthesis in human skeletal muscle. Glutathione has multiple metabolic functions that are involved in cellular homeostasis. It is unknown how surgical trauma affects the glutathione metabolism of skeletal muscle in surgical patients. METHODS: Eight patients undergoing elective abdominal surgery were investigated. Percutaneous muscle biopsies and blood samples were taken before operation and at 6, 24, and 48 hours after operation. The concentrations of glutathione were determined in muscle tissue, plasma, and whole blood, as well as the concentrations of the related amino acids in muscle and plasma. RESULTS: In skeletal muscle, the levels of both reduced and total glutathione decreased by 40% (p<0.01) at 24 hours and remained low at 48 hours after operation compared with the preoperative values. The glutathione concentration in plasma was 20% lower after operation compared with the concentration before operation (p<0.05). There were no changes at the whole blood levels of glutathione. Tissue glutamate and glutamine decreased significantly after operation (p<0.001), whereas intracellular cysteine and glycine remained unchanged. CONCLUSIONS: Skeletal muscle glutathione deficiency occurs after surgical trauma. This may lead to an increase in the susceptibility to intracellular oxidative injury.

Adult↗