Biomedical subjects

M Møller

Publications and source records attributed to M Møller.

244 records · Page 14Linked to original sources

PubMedDate not supplied

Standard ECG versus 24-hour Holter monitoring in the detection of ventricular arrhythmias.

A total of 386 corresponding registrations of standard ECG and 24-h Holter monitoring were compared in order to elucidate the information obtainable from a 60-s standard ECG with regard to ventricular arrhythmias. Ventricular ectopic beats (VEB) were present on 17% of the standard ECG against 90% of the monitorings (p less than 0.001). The corresponding figures for complicated VEB (multiform, repetitive, R on T) were 2% and 41%, respectively (p less than 0.001). The presence of VEB on the standard ECG was associated with a significantly increased incidence of all types of ventricular arrhythmias during Holter monitoring performed within the same day. The number of VEBs on the standard ECG did not predict the number during monitoring, but to some extent did predict the occurrence of complicated types. In 52 patients free from VEB on four consecutive standard ECGs, Holter monitoring showed complicated ectopic activity in 32 (62%). Thus standard ECG is an insensitive method for the detection of ventricular arrhythmias.

Arrhythmias, Cardiac↗

PubMedDate not supplied

Mutagenicity of polycyclic aromatic compounds (PAC) identified in source emissions and ambient air.

Several polycyclic aromatic compounds (PAC) including nitrated and oxygenated derivatives of polycyclic aromatic hydrocarbons (PAH) were tested for mutagenic activity in the Salmonella/microsome assay. Among the compounds tested the isomer mix of nitro-1-hydroxypyrenes showed the highest direct mutagenic response in both the Salmonella strain TA98 and TA100 (1251 revertants/micrograms and 463 revertants/micrograms, respectively). The direct-acting mutagenicity of the nitro-1-hydroxypyrene isomer mix was dependent upon reduction of the nitro function as evidenced by the decrease in activity observed with the nitroreductase-deficient and arylhydroxylamine esterifying-deficient tester strains. The oxygenated derivatives of PAH containing aldehyde or keto groups showed weak or no mutagenic responses. In most cases addition of S9 was essential for any mutagenic activity and the strain TA100 was more sensitive than the strain TA98. Within this group, 7H-dibenzo[c,g]fluoren-7-one showed the highest mutagenic effect; 7 and 22 revertants/micrograms using the strains TA98 and TA100, respectively.

Air Pollutants↗

PubMedDate not supplied

Induced fluorescence of serotonin in paraffin sections from carcinoid tumors.

The detection of argentaffin cells and carcinoid tumor cells would be greatly facilitated if it were possible to apply methods of induced fluorescence directly on paraffin sections. We have subjected 5 microgram thick sections from paraffin blocks containing carcinoids to different procedures for induced fluorescence. These include formaldehyde vapor at 80 degrees C for 1 hour, 5% paraformaldehyde solution at room temperature followed by heating to 80 degrees C for 15 min, and sucrose-phosphate buffer-glyoxylic acid solution either for 3 seconds at room temperature followed by heating to 80 degrees C for 15 min or 15 min at 60 degrees C in the solution. The different procedures were applied to sections which were non-deparaffinized, deparaffinized or deparaffinized and rehydrated to various degrees. With all procedures used we were able to induce histofluorescence of argentaffin cells and carcinoid tumor cells, and it was confirmed by microspectrofluorometry that the fluorophore originated from serotonin. Best results, when morphology was taken into consideration, were obtained with sections deparaffinized, transferred to 96% ethanol and then exposed to formaldehyde vapor.

Carcinoid Tumor↗

PubMedDate not supplied

Innervation of the rat pineal gland by nerve fibres originating in the sphenopalatine, otic and trigeminal ganglia. A retrograde in vivo neuronal tracing study.

The innervation of the rat pineal gland from the sphenopalatine, otic, superior cervical and trigeminal ganglia was investigated in animals by use of in vivo retrograde tracings. A solution of 2% Fluorogold was iontophoretically injected into the superficial pineal gland in a series of Wistar rats. After a survival time of 4-10 days, the animals were fixed by perfusion and the brains, sphenopalatine, otic, superior cervical and trigeminal ganglia were investigated with a fluorescence microscope. Many retrogradely labelled perikarya were found in the superior cervical ganglia, but a smaller number of neurones were also labelled in the sphenopalatine, otic and trigeminal ganglia. Injections of the tracer into the subarachnoidal space were used as the control for unspecific uptake and transport of the tracer. The input to the pineal gland from the parasympathetic sphenopalatine and otic ganglia might be involved in the regulation of the annual rhythms of the pineal gland. The projections from the sensory trigeminal ganglion could be involved in the control of the blood flow of the gland.

Afferent Pathways↗

PubMedDate not supplied

Dofetilide in patients with congestive heart failure and left ventricular dysfunction: safety aspects and effect on atrial fibrillation. The Danish Investigators of Arrhythmia and Mortality on Dofetilide (DIAMOND) Study Group.

INTRODUCTION. Atrial fibrillation is a frequent cause of worsening of symptoms in patients with congestive heart failure. The drugs currently available for maintenance of sinus rhythm all have major side effects. METHODS. In 34 Danish coronary care units, 1518 patients with congestive heart failure and reduced left ventricular systolic function were randomized to receive either placebo or a new class III antiarrhythmic drug, dofetilide. The dose of dofetilide was adjusted according to the presence of atrial fibrillation, the length of the QT interval, and renal function. Patients were continuously monitored electrocardiographically for the first 3 days of the study. The primary end point was all-cause mortality and follow-up was for at least 1 year. RESULTS. In the dofetilide/placebo groups, 311/317 patients died (41%/42%). The hazard ratio for dofetilide treatment was 0.95 (95% confidence interval, 0.81-1.11). Treatment with dofetilide reduced worsening of heart failure significantly (hazard ratio, 0.75; 0.63-0.89). After 1 year, 61% of patients with atrial fibrillation at the start of the study had converted to sinus rhythm on dofetilide, vs. 33% in the placebo group. After conversion to sinus rhythm, 78%/43% of patients in the dofetilide/placebo groups remained in sinus rhythm for at least 1 year. There were 25 instances (3%) of torsade de pointes ventricular tachycardia in the dofetilide group and none in the placebo group. CONCLUSION. In patients with congestive heart failure, dofetilide can effectively convert atrial fibrillation to sinus rhythm and maintain sinus rhythm after conversion. Hospitalization for congestive heart failure is reduced. Dofetilide does not affect mortality. (c)2001 by CHF, Inc.

Journal Article↗

PubMedDate not supplied

Fractal correlation properties of R-R interval dynamics and mortality in patients with depressed left ventricular function after an acute myocardial infarction.

BACKGROUND: Preliminary data suggest that the analysis of R-R interval variability by fractal analysis methods may provide clinically useful information on patients with heart failure. The purpose of this study was to compare the prognostic power of new fractal and traditional measures of R-R interval variability as predictors of death after acute myocardial infarction. METHODS AND RESULTS: Time and frequency domain heart rate (HR) variability measures, along with short- and long-term correlation (fractal) properties of R-R intervals (exponents alpha(1) and alpha(2)) and power-law scaling of the power spectra (exponent beta), were assessed from 24-hour Holter recordings in 446 survivors of acute myocardial infarction with a depressed left ventricular function (ejection fraction </=35%). During a mean+/-SD follow-up period of 685+/-360 days, 114 patients died (25.6%), with 75 deaths classified as arrhythmic (17.0%) and 28 as nonarrhythmic (6.3%) cardiac deaths. Several traditional and fractal measures of R-R interval variability were significant univariate predictors of all-cause mortality. Reduced short-term scaling exponent alpha(1) was the most powerful R-R interval variability measure as a predictor of all-cause mortality (alpha(1) <0.75, relative risk 3.0, 95% confidence interval 2.5 to 4.2, P<0.001). It remained an independent predictor of death (P<0.001) after adjustment for other postinfarction risk markers, such as age, ejection fraction, NYHA class, and medication. Reduced alpha(1) predicted both arrhythmic death (P<0.001) and nonarrhythmic cardiac death (P<0.001). CONCLUSIONS: Analysis of the fractal characteristics of short-term R-R interval dynamics yields more powerful prognostic information than the traditional measures of HR variability among patients with depressed left ventricular function after an acute myocardial infarction.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

Brainstem evoked potentials in adult sleep apnea.

Brainstem evoked potentials (BSEP) were recorded in 23 patients with adult sleep apnea (ASA). Three patients were studied with all-night polysomnography prior to our testing. They were categorized as having obstructive, central, or mixed sleep apnea depending on the predominant sleep findings. All patients with central sleep apnea had abnormal BSEP with prolongation of wave V. A majority of the remaining patients with obstructive sleep apnea and mixed sleep apnea had abnormal BSEP, but without specific configurations. These findings substantiate our hypothesis that brainstem dysfunction may play a role in ASA.

Adult↗

PubMedDate not supplied

Gamma knife: an alternative treatment for acoustic neurinomas.

Despite surgical advances and technologic means of better monitoring seventh and eighth nerve function intraoperatively, there remains a group of patients for whom alternative methods of treatment are desirable. These include the elderly, those with bilateral tumors or tumors in only hearing ears, individuals with medical contraindications to major surgery, and those who refuse surgical resection. The University of Pittsburgh became the fifth world center and the first in the United States to install the "gamma knife" for stereotactic radiosurgery. On the basis of the pioneering work done at the Karolinska Institute in Stockholm, acoustic tumor patients who fulfill the above criteria are being treated. A tumoricidal single treatment closed-skull radiation dose is given through 201 sharply focused cobalt 60 sources, minimizing the effects on surrounding brain or other tissues. Our early results are discussed and compared to those from more than 200 cases in Stockholm. Complications and expected long-term results are presented.

Cobalt Radioisotopes↗

PubMedDate not supplied

Expression of thyrotropin-releasing hormone messenger RNA in human pituitary adenomas with follicle-stimulating hormone immunoreactivity.

OBJECTIVE: To assess the correlation between thyrotropin-releasing hormone (TRH) messenger RNA (mRNA) and the immunoreactive type of human pituitary adenomas. METHODS: Twenty-eight patients (14 to 73 years old) who had pituitary adenomas (18 nonfunctioning adenomas, 8 growth hormone-secreting adenomas, and 2 prolactinomas) underwent surgical treatment. Pituitaries removed at autopsy from four patients without evidence of pituitary disease were used as controls. Fragments of pituitary adenomas were processed for TRH mRNA by in situ hybridization (radioactive and nonradioactive) and for TRH peptide and anterior pituitary hormones (b-thyrotropin, b-follicle-stimulating hormone [FSH], bluteinizing hormone [LH], prolactin, and growth hormone) by immunohistochemistry with use of the avidinbiotin technique. Quantitative immunohistochemical studies were performed by using image analysis software. The signal was considered positive when more than 5% of the cells were stained. RESULTS: Cells expressing TRH mRNA were detected in 22 of 28 pituitary adenomas--15 of 18 nonfunctioning pituitary adenomas, 5 of 8 growth hormone-secreting adenomas, and both prolactinomas. TRH peptide was revealed in only 10 adenomas, all expressing TRH mRNA as well. All but one nonfunctioning adenoma expressing TRH mRNA in more than 5% of the cells were b-FSH immunoreactive (15 of 16 cases; P<0.005, c 2 test), whereas only 6 of 16 nonfunctioning adenomas exhibited both b-thyrotropin and TRH mRNA and only 5 of 16 were positive for both b-LH and TRH mRNA. CONCLUSION: These results confirm previous data demonstrating the presence of TRH mRNA and TRH peptide in human pituitary tumor cells. We further showed that the presence of TRH mRNA is significantly correlated with FSH immunoreactive gonadotropinomas. The release of FSH after an intravenous TRH test only in gonadotropinomas, together with local production of TRH, suggests a role for TRH in pathogenesis.

Journal Article↗

PubMedDate not supplied

Effect of He-O2, O2, and N2O-O2 breathing on injected bubbles in spinal white matter.

Injected air bubbles in spinal white matter in the rat were studied at 1 bar after decompression from an exposure to air at 3.1 bar (absolute) for 4 h. During air breathing all injected bubbles grew for the first 2 h of the observation period. Thereafter three of nine bubbles began to shrink and one of them disappeared. During breathing of heliox (80:20) bubbles consistently shrank and disappeared from view. If the breathing gas was changed from heliox to N2O-O2 (80:20), while bubbles still had an appreciable size, they started growing again. If the change to N2O-O2 was done after a bubble disappeared from view, it did not reappear. During breathing of 100% oxygen, all bubbles initially grew. Subsequently they all shrank and disappeared at about the same time after gas shift, as during heliox breathing. The effect of heliox treatment on CNS decompression sickness after air dives is discussed.

Adipose Tissue↗