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Biomedical subjects

I Nielsen

Publications and source records attributed to I Nielsen.

At least 37 records · Page 2Linked to original sources
PubMed1994

Pathobiological effects of acetaldehyde in cultured human epithelial cells and fibroblasts.

The ability of acetaldehyde, a respiratory carcinogen present in tobacco smoke and automotive emissions, to affect cell viability, thiol status and intracellular Ca2+ levels and to cause DNA damage and mutations has been studied using cultured human cells. Within a concentration range of 3-100 mM, a 1 h exposure to acetaldehyde decreases colony survival and inhibits uptake of the vital dye neutral red in bronchial epithelial cells. Acetaldehyde also causes both DNA interstrand cross-links and DNA protein cross-links whereas no DNA single strand breaks are detected. The cellular content of glutathione is also decreased by acetaldehyde, albeit, without concomitant changes in the glutathione redox status or in the content of protein thiols. Transient or sustained increases in cytosolic Ca2+ occur within minutes following exposure of cells to acetaldehyde. Moreover, acetaldehyde significantly decreases the activity of the DNA repair enzyme O6-methylguanine-DNA methyltransferase. Finally, a 5 h exposure to acetaldehyde causes significant levels of 6-thioguanine resistance mutations in an established mutagenesis model involving skin fibroblasts. The results indicate that mM concentrations of acetaldehyde cause a wide range of cytopathic effects associated with multistep carcinogenesis. The fact that acetaldehyde, in relation to its cytotoxicity, causes comparatively higher genotoxicity and inhibits DNA repair more readily than other major aldehydes in tobacco smoke and automotive emissions is discussed.

Acetaldehyde↗
PubMed1993

[AIDS--knowledge, behavior and attitude at the University of Aarhus in 1990. A questionnaire study].

To describe knowledge, attitude and behaviour regarding AIDS among students and employees at the University of Aarhus an anonymous self-administered questionnaire survey was conducted in April 1990. Of the 2169 and 850 questionnaires to students and employees, respectively, 1548 (71.4%) and 568 (67%) were returned. The study group had an excellent knowledge about AIDS and the transmission of HIV-virus. However, when defining "risk behaviour" in relation to transmission of HIV-virus among heterosexuals as "> or = 2 sexual partners within the past year without using condoms" 27% of the male and 20% of the female students showed risk behaviour. Among employees the rate was highest (23%) among the male scientific staff than among the remainder (17%). It is concluded that risk behaviour was not related to age and occurred in spite of the fact that 42% of the students and 31% of the employees, who showed risk behaviour were also aware of a personal risk of being infected. There is still a need for information about AIDS, and future campaigns should be directed towards all age groups as risk behaviour is not only a phenomenon among young people.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Structural changes of duodenum brush border in lung cancer patients treated with cisplatin plus etoposide.

The effects of cisplatin plus etoposide chemotherapy (PE) on the structure of proximal intestine villi and brush border were investigated in 10 patients with lung cancer. The day before starting chemotherapy (time 1); 8 days after its initiation (time 2), and one month after the 3rd course of PE (time 3) they underwent esophagogastroduodenoscopy and three biopsies were taken from the descending duodenum. Intestinal villi were examined by light microscopy; brush border by transmission electron microscopy. No significant histological changes of villous pattern were observed at times 2 and 3. The height of microvilli was reduced in seven patients at time 2 (P < 0.05). Microvilli abnormalities (i.e. rarefaction and/or heterogeneity in their height) were present in nine patients at time 2 (P < 0.05). Brush border appearance at time 3 did not differ from that at time 1. PE chemotherapy seems to have short-term toxic effects on small intestine brush border, but does not cause chronic enteropathy.

Adult↗
PubMed1993

Sweet's syndrome and malignancy: report of the first case associated with adenocarcinoma of the lung.

Sweet's syndrome is a rare dermatosis characterized by fever, neutrophilia, raised painful erythematous plaques and a dense dermal infiltrate consisting of mature neutrophils. About 15% of published cases occurs in association with hematologic malignancies, so that the syndrome is considered a paraneoplastic phenomenon; conversely, the association with solid tumors is very rare (up to now seven cases). We report the first case of Sweet's syndrome associated with adenocarcinoma of the lung. The syndrome appeared when the tumor was in remission after five courses of chemotherapy, and remained the only sign of underlying malignancy for 2 months, when lung cancer relapsed.

Adenocarcinoma↗
PubMed1992

Serum and erythrocyte magnesium concentrations in solid tumours: relationship with stage of malignancy.

Magnesaemia is often decreased in solid tumours, but magnesium (Mg) is mainly an intracellular cation and serum levels do not reflect actual body stores. In this study serum Mg (SMg) and erythrocyte Mg (EMg) concentrations were measured in 40 healthy controls and in 108 patients affected by various types of tumour (50 lung cancers, 25 breast cancers, 18 ovarian cancers, and 15 oropharyngeal and hypopharyngeal cancers). EMg was higher (P < 0.05) and SMg lower P < 0.001) in neoplastic patients than in controls. All tumour types behaved in the same way, though in the lung cancer group the increase in EMg did not reach statistical significance in comparison with the control group (P = 0.05). The extent to which EMg was increased and SMg decreased was positively correlated with the advancement in the stage of malignancy. These results suggest that in neoplastic disease Mg requirement is not only increased in tumour tissue, but also in erythrocytes. The increase in EMg may derive from a change in the red blood cell membrane, facilitating intracellular concentration of magnesium for transport to the tumour. The concomitant decrease in SMg may be the consequence of the enhanced erythrocyte uptake of magnesium from the extracellular circulating pool.

Adult↗
PubMed1991

Adaptability of the adult primate craniofacial complex to asymmetrical lateral forces.

The adaptability of the adult craniofacial skeleton to altered functional relationships has been reported. An experimental quantification of these changes is lacking, however, and the possible underlying mechanisms of the alterations have not been explained. The purpose of this investigation was to evaluate the effect that lateral displacement of the mandible has on the dentoalveolar, craniofacial, and neuromuscular system in the adult rhesus monkey. Ten adult monkeys were studied; five served as controls, three were fitted with bilaterally inclined mandibular splints designed to deviate the mandible toward the left on closure, and two animals had flat splints to provide even occlusal contact. Pretreatment and posttreatment assessment of dentoalveolar and craniofacial change was made from mounted study casts, cephalometric head films, electromyograms and computed tomograms. Axial computed tomographic scans were used to evaluate potential changes in bone density at the lower part of the mandible, the condyle, the coronoid process, the neck of the condyle, and the zygomatic arch by means of a one-way analysis of variance. Changes in the measured variables were not observed in the control animals or in the animals with flat splints. Animals with inclined splints, however, demonstrated attrition and intrusion of maxillary molars and mild proclination of the maxillary incisors. Posttreatment computed tomographic scans in these animals showed significantly increased bone density in the right coronoid process (p less than 0.05) and bilaterally at the necks of the condyles (p less than 0.005). Resting electromyographic activity remained low and was not significantly different among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1991

Early and late hyperferremia during cisplatin chemotherapy.

Changes in plasma iron levels were evaluated in 48 neoplastic patients receiving a total of 56 courses of polychemotherapy in which high doses of cisplatin were administered on day 1. Serum iron showed a three-fold mean increase 24 hours after cisplatin infusion, rising from a basal mean value of 78.25 +/- 45.74 micrograms/dl to 242.12 +/- 72.67 micrograms/dl (P less than 0.001). Hyperferremia began to lower after the 3rd day and pretreatment levels were again observed the 10th day. Ferritin increased progressively from a basal mean value of 565.81 +/- 435.18 micrograms/l to 928.73 +/- 665.41 micrograms/l the 7th day (P less than 0.001). Hemolysis and tissutal necrosis were excluded, since red cells, hemoglobin, muscular and hepatic enzymes and indirect bilirubin remained unmodified. Reticulocytes began to lower on the 3rd day and reached the nadir the 7th day: therefore the cisplatin-induced blockage of erythropoiesis, with consequent reduced iron use was maximum the 3rd day--as observed in animals by other Authors--and could not explain the early hyperferremia developing within 24 hours. Consequently hyperferremia seems to consist of two overlapping stages: an early stage by unknown interference of cisplatin on iron-loaded reticulo-endothelial cells, with consequent acute iron emissions into the blood stream; and a later stage by toxic effect of the drug on erythroid precursors with reduced iron uptake by bone marrow.

Aged↗
PubMed1991

Acute gastroduodenal mucosal injury after cisplatin plus etoposide chemotherapy. Clinical and endoscopic study.

The effects on gastric and duodenal mucosa induced by cisplatin plus etoposide (PE) chemotherapy were investigated in 32 patients with lung cancer. They were submitted to gastroduodenoscopy before receiving cisplatin 100 mg/m2 (day 1) plus etoposide at a mean dose of 107 mg/m2 (days 1, 3 and 5). Endoscopic examination was repeated on day 8. Before chemotherapy, 22 patients showed normal endoscopic appearance and 10 minimal lesions (3 or fewer erosions). After chemotherapy, 16 remained normal, 1 had minimal lesions and 15 developed major lesions: 11 gastric or duodenal multiple erosions, 1 diffuse erosive gastritis, 2 gastric and 1 duodenal ulcer (p less than 0.001). No difference was observed in the number of vomiting episodes nor in severity of upper gastrointestinal symptoms between the patients who remained normal and those who developed mucosal injury. We conclude that PE chemotherapy can have a properly called gastroduodenal toxicity, leaving nausea and vomiting out which are rather due to central than peripheral mechanisms. Some trials are necessary to investigate which kind of drugs (H2-receptor blockers, sucralfate, prostaglandin E analogues) may be useful in preventing acute gastroduodenal mucosal injury induced by PE chemotherapy.

Adult↗
PubMed1991

[CEA, GICA, TPA, fibrinopeptide-A, gamma-GT and gastric cancer. A contribution to the rationalization of a combined assay].

CEA, GICA, TPA, Fibrinopeptide-A (FpA) and Gamma-GT serum levels were evaluated in 312 patients affected by gastric cancer, to assess their effectiveness in diagnosis, evaluation of disease extension and follow-up of gastric cancer. In 204 patients neoplasia was limited to the stomach, in 108 liver metastases, ascertained by ultrasonography and/or TAC, were present. CEA was increased in 224 cases (71.8%); mean values were significantly higher in metastatic patients than in metastasis-free group (p less than 0.001), but overlap of values between the two groups was observed in about one third of cases. GICA was increased in 268 patients (86%) and TPA in 306 (98%), without significant differences between metastatic and metastasis-free group. FpA was increased in all patients; when metastases were present it was significantly higher than in metastasis-free patients (p less than 0.001), with negligible overlap of values between the two groups. Gamma-GT was normal in 202 metastasis-free patients (99%) and increased in 105 patients with liver metastases (97%). On the basis of these data CEA does not seem to have striking diagnostic sensibility nor reliability in differentiating presence from absence of liver metastases in patients with gastric cancer. Combined assay of TPA, FpA and Gamma-GT seems to be the most reliable serological approach in diagnosis, staging and follow-up of gastric cancer.

Adult↗
PubMed1991

Effect of verapamil on ischemia and ventricular arrhythmias after an acute myocardial infarction: prognostic implications. The Danish Verapamil Infarction Trial II Study Group.

This article is a review of presented subsets of the Danish Verapamil Infarction Trial II (DAVIT II) regarding the effect of verapamil on postinfarction ischemia, ventricular arrhythmias, and heart rate (HR), and the prognostic implications of these findings. Patients underwent Holter monitoring for 24-48 h at 1 week, i.e., before randomization to long-term treatment with placebo or verapamil, and after 1 month and about 1 year of study treatment. Ischemia: 18% of the patients had transient ST-segment deviation before randomization; 24% of the placebo- and 8% of the verapamil-treated patients (p = 0.04) showed ischemia after 1 month; and after 1 year, the figures were 26 and 4%, respectively (p = 0.02). The 18-month major event rate, i.e., first reinfarction or death, in patients with ischemia before randomization were 40 and 23.8% in patients without ischemia (p = 0.06). Arrhythmias: In the placebo group the prevalence and incidence of many ventricular ectopic beats (VEBs), i.e., more than 10 VEBs/h, increased significantly during the first years after infarction; this was not the case in the verapamil patients group. The mean HR was significantly reduced by verapamil treatment after 1 month and after 16 months of treatment. Multivariate analysis demonstrated the presence of more than 10 VEBs/h only early (i.e., 1 week) but not late (i.e., 1 month) after infarction, to be an independent predictor of major events during 18 months' follow-up observation. A HR above 80 beats/min independently predicted major events when appearing both early and late after infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Hyperkalaemia during infusion of hyperosmolar amino acid solutions enriched with branched chain amino acids. Report of two cases.

We report two cases of unexplained hyperkalaemia during infusion of amino acid solutions enriched with branched chain amino acids. The increase in potassium levels developed 24 hours after starting infusion and normalization was obtained within 24 hours after stopping infusion. Acidosis, acute renal failure, concomitant cell destruction and haemolysis were excluded; antialdosteronic diuretics were not given. The authors hypothesize that hyperkalaemia could be due to a sudden increase in plasmatic osmolality caused by the hyperosmolarity (900 mOsm/l) of the solution, not counterbalanced by adequate ADH release owing to malfunctioning of hypothalamic osmoreceptors. At present this hypothesis is lacking in experimental proofs.

Aged↗
PubMed1991

Changes in serum, erythrocyte, and urinary magnesium after a single dose of cisplatin combination chemotherapy.

The changes in serum and erythrocyte Mg concentrations and in renal Mg excretion induced by a single dose of cisplatin (100 mg/mq body surface area) were investigated in 16 patients with lung cancer. Magnesuria increased significantly (P less than 0.001) the day after cisplatin administration, returned to basal levels in the following days, and increased again on the 7th day (P less than 0.05). Magnesaemia decreased gradually and after 7 was significantly lower than before treatment (P less than 0.05). Erythrocyte Mg decreased significantly on days 1 (P less than 0.05) and 2 (P less than 0.001) after cisplatin administration, began to increase on day 4, and recovered to pretreatment values on day 7. These results suggest that, besides the well known damage to tubular function with consequent increase in renal Mg wasting, cisplatin may also interfere with Mg metabolism at cellular and subcellular levels. The activity of the drug on nucleic acids and membrane transport systems, where Mg is abundant and exerts important stabilizing functions, could induce Mg mobilization and increased membrane permeability, with a consequent shift of Mg from cells into the blood stream. This would counterbalance the increase in magnesuria, and magnesaemia would decrease significantly only when intracellular Mg returns to pretreatment levels.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

Deregulation in trans or c-myc expression in immortalized human urothelial cells and in T24 bladder carcinoma cells.

The expression of a number of cellular oncogenes was investigated in human urothelial cell lines with different in vitro growth properties. Constitutively elevated levels of expression of c-myc RNA were found in Hu609, an immortalized, nontumorigenic cell line that was derived from normal urothelium, and in the bladder carcinoma cell line T24. Potential mechanisms that might underlie deregulation of c-myc expression in these cells were investigated. It was found that the c-myc gene was apparently intact and not amplified in Hu609 and T24. No increased stability of c-myc RNA was detected. A c-myc-CAT fusion construct containing 2.5 kb of normal c-myc 5' sequences showed levels of expression that paralleled the overexpression of the endogenous gene, indicating that the high constitutive levels of c-myc expression were due, at least in part, to alterations in the activities of cellular trans-acting transcriptional regulators.

Animals↗