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Biomedical subjects

I Nielsen

Publications and source records attributed to I Nielsen.

At least 19 recordsLinked to original sources
PubMed1995

Atypical absorption of morphine sulphate through oral mucosa: an unusual case of acute opioid poisoning.

An unusual case of probable opioid poisoning due to atypical absorption of morphine sulphate through the oral mucosa is reported. A patient with advanced laryngeal cancer, who was unable to swallow, became stuporous, bradypneic, and cyanotic and had pinpoint pupils 1 hour after taking a controlled-release tablet of morphine sulphate 30 mg. Intravenous naloxone 0.4 mg induced prompt reversal of the clinical picture. The tablet of morphine, in advanced stage of decomposition, was found in the patient's mouth, the mucosa of which was inflamed and extensively ulcerated because of the long-standing stagnation of food residuals. Usually morphine is not amenable to transmucosal absorption, because of its low lipid solubility. In this case, the retention of the tablet of morphine in the mouth and the breakdown of oral mucosa integrity could have provoked a quick transmucosal absorption of the drug, with by-pass of hepatic first-pass metabolism. This may have induced a peak in drug concentration much higher than that usually resulting from the enteric absorption of controlled-release tablets of morphine.

Absorption↗
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↗
PubMed1988

Response patterns of craniomandibular muscles with and without alterations in sensory feedback.

1. Surface EMG recordings were made bilaterally from the anterior part of the temporal muscle, superficial masseter muscle, and the suprahyoid complex of muscles while tracking mandibular incisor movement in three planes. This was done in 20 normal subjects with 16 different responses. Some responses involved clenching whereas other responses occurred with actual mandibular movement. 2. Each muscle demonstrated a probability of recruitment dependent on the response that correlated with the intensity of recruitment. The higher the probability of recruitment, the greater the intensity of muscle activity. 3. The anterior temporal muscle demonstrated no statistically significant difference in any of the responses between the left and right muscles. The masseter muscle also demonstrated bilateral symmetry. 4. The anterior part of the temporal muscle was recruited in more than 60% of its trials (60% to 100%) in ipsilateral laterotrusion, retrusion, fast vertical raising, clenching on the ipsilateral or intercuspal position, and mastication. The temporal muscle was recruited in less than 60% of its trials in contralateral and incisor clenching, and less than 30% in contralateral laterotrusion, protrusion, and opening. 5. The superficial masseter muscle was recruited in more than 60% of its trials in protrusion, vertical raising, all clenches, and mastication. The masseter muscle was recruited less than 60% in retrusion, ipsilateral laterotrusion, and opening. 6. The suprahyoid group of muscles was recruited in more than 60% of its trials in protrusion, opening, and mastication. This group of muscles was recruited less than 60% of the time in clenching, lateral movements, and rapid vertical raising of the mandible. 7. Applying a maxillary splint to seven subjects significantly decreased the recruitment of the anterior temporal and masseter muscles during mastication. The splint also modified the use of the masseter muscle during protrusion so that it was less active, but increased its recruitment during contralateral clenching. The suprahyoid muscle group was unaffected by the maxillary splint. 8. These data support the concept that movement of the mandible from the intercuspal or rest position develops a coactivation pattern that will excite or inhibit a given muscle regardless of whether clenching with occlusal contacts or no occlusal contact is involved. 9. The data also demonstrate that the maxillary splint can alter the use of the jaw elevator muscles, predominantly in mastication.

Adult↗
PubMed1988

Craniomandibular bone density in the primate as assessed by computed tomography.

Ten normal rhesus monkeys, five juvenile and five adult animals, were analyzed for symmetry in bone density across the cranioskeleton with computed tomography (CT). Fifty contiguous axial CT scans were done using 1.5-mm thick scans between the lower mandibular border and inferior orbital ridge, and 3-mm thick scans from the inferior orbital ridge to the rostral level of insertion of the temporalis muscle. Eleven regions comprising areas of the lower mandibular border, lower ramus, upper ramus with condyle, the coronoid process, the zygomatic arch, and cranial bone were analyzed for symmetry using small regions of interest. Only one region, the condyle, demonstrated a statistically significant difference between the two sides with all other measured sites demonstrating the same bone mineral density bilaterally. Large area analysis of five regions--the lower mandibular border, upper ramus with condyle, the coronoid process, the zygomatic arch, and upper cranium--demonstrated no significant difference in the distribution of CT numbers. This analysis of bilateral distribution of bone density in the primate craniofacial skeleton demonstrates a basic symmetry that can be used to study altered patterns of neuromuscular function and their effects on bone density.

Aging↗
PubMed1986

The natural history of hypertensive heart disease as suggested by echocardiography.

Heart morphology and function in hypertension is viewed as a continuum between the following types as land marks: concentric/septal hypertrophy and increased systolic function. slightly dilated left ventricle, no hypertrophy, increased systolic function. eccentric hypertrophy, slightly reduced systolic function. dilated cardiomyopathy without signs of ischaemic heart disease. dilated cardiomyopathy with signs of ischaemic heart disease. The time course of the development of hypertensive heart disease is suggested.

Adolescent↗