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Biomedical subjects

A Ahonen

Publications and source records attributed to A Ahonen.

106 records · Page 6Linked to original sources
PubMed1975

Effects of 400 R whole-body x-irradiation on 5-hydroxytryptamine content of the rat gastrointestinal tract.

The effects of a single 400 R whole-body dose of X-irradiation on the regional 5HT content of the gastrointestinal (G. I.) tract were studied from four hours to 40 days after irradiation. The total 5HT content of various G.I. tissues was determined and 5HT was also determined per unit of body weight, wet weight of tissue and tissue protein. Irradiation caused an immediate decrease of the amine content of various G.I. regions in adult rats. This was followed by recovery, the degree of which varied in different regions. Some minor morphological changes were seen in enterochromaffin cells one and two days after irradiation but not later. The effects of irradiation on the G.I. tissues were stronger in young rats, in whom no complete recovery of 5HT occurred within 45 days. The present results support the view that irradiation exerts a direct damaging effect on the gastrointestinal 5HT storage, which is associated with liberation of 5HT from amine-containing cells. The duration of the effect varies with age and intestinal segment concerned.

Age Factors↗
PubMed1975

Effects of fasting and feeding and pilocarpine on paneth cells of the mouse.

The effects of fasting and feeding and pilocarpine on Paneth cells (PC) of the mouse were studied by labelling the secretory granules of PC with dopamine and by counting the number of granules. Pilocarpine stimulated the extrusion of granules from the cytoplasm of the cells and significantly decreased their number, whereas fasting for 2 days significantly increased the granule count of cells. Standard food did not have any effect on PC of the duodenum, whereas in the jejunum resuming eating after 2 days fasting significantly decreased the number of granules when compared with the mice deprived of the food.

Animals↗
PubMed1975

Studies of rectal mucosal catecholamines in ulcerative colitis.

Rectal mucosal biopsies from six patients suffering from ulcerative colitis were studied by estimating the catecholamine (CA) content and by fluorescence microscopy. Adrenergic nerve fibres were relatively scanty both in diseased and control patients. The adrenergic structures seem well preserved in the affected areas of the colon, although the nonspecific collagenous autofluorescence makes interpretation difficult. There was a significant rise in the noradrenaline (NA) content compared with the seven control patients (p smaller than 0.01). This may be a compensatory phenomenon to inhibit increased intestinal motility. The increased NA level may be due to the intense perivascular adrenergic plexus typical for ulcerative colitis. In both groups there were varying amounts of fluorescing enterochromaffin cells probably without relation to the diagnosis.

Adult↗
PubMed1975

Studies of catecholamines in amyloidosis.

Amyloidosis was induced in 21 mice by daily injections of casein solution for four weeks. Thioflavine T staining showed that the induction of amyloidosis took place in all mice. The catecholamine (CA) content was estimated in the spleen, proximal colon and kidney. In spleen the noradrenaline (NA) content per wet weight of tissue in casein-induced amyloidosis was significantly (p less than 0.01) lower than in the controls but this reduction was not apparent because of the huge increase in the weight of amyloid spleens. In the proximal colon and kidney the NA content did not differ from the control values. By fluorescence histochemistry the adrenergic fibres appeared to be well maintained in the spleen, duodenum and proximal colon in casein-induced amyloidosis. The CA content of rectal mucosal biopsies from five patients suffering from amyloidosis was compared with that from seven control persons. There was no significant difference in NA content. The present results suggest that in amyloid disease detectable alterations in the CA content or such morphological changes in adrenergic nerve fibres, which can be detected by fluorescence histochemistry take place only in the most advanced disease, if at all.

Amyloidosis↗
PubMedDate not supplied

An international comparison of mortality in middle-aged men from cardiovascular diseases during 1970--1974.

An international comparison of mortality rates in middle-aged men (35--54 years) from cardiovascular diseases (CVD) during the period 1970--1974 was made. The material for this study was obtained from the statistics of the WHO (World Health Statist. Ann. 1970--1974, Vol. I, Vital Statistics of Causes of Death. WHO, Geneva, 1973--1976). The mean death rate of middle-aged men from all CVD and ischaemic heart diseases was clearly higher in Finland than in any other country in the world during the 5-year period. The mortality rates according to all ICD (International Classification of Diseases) main groups of diseases were determined for a selected group of countries containing all the Scandinavian countries, the United States, Canada, Hungary, Australia, Scotland, and Czechoslovakia. The death rates of all natural (ICSI-XVI) and unnatural causes (ICDXVII) were higher in Finland than in the other selected countries. Also the proportion of cardiovascular deaths as a percentage of all natural deaths was clearly higher in Finland than in any of the above countries, whereas in these countries proportionally more deaths were due to neoplasms than in Finland, especially in men aged 35--44. Only in Hungary did infectious diseases account for about 4.5% of all natural deaths; in the other countries they accounted for only about 1--2%. In the United States, Sweden, Czechoslovakia and Canada a clearly higher relative number of deaths (about 9--13%) were due to diseases of the digestive system than in the other countries (about 3--9%), whereas the relative numbers of deaths from respiratory and genitourinary diseases were uniform among all selected countries. Only in Denmark and Norway was a prominent proportion of the deceased (3.5--9.5%) certified as having died due to some symptom or ill-defined condition. About 90% of all middle-aged men died in each country from various diseases of the above six main ICD categories. As a whole, the above single deviations from the general trend were so small that the present results do not support the view that the differences in certifying and coding practices could explain the significant differences found in cardiovascular mortality of middle-aged men between various countries.

Adult↗
PubMedDate not supplied

The epidemiology of autopsies in cardiovascular deaths of middle-aged men in Finland in 1973.

There were 414 certified deaths from cardiovascular diseases (CVD) in men aged 35--44, and 1372 at ages 45--54, in Finland during 1973. A detailed analysis of the examination of the cause of death in these cases was made by paying specific attention to the autopsy epidemiology. In men aged 35--44 years 68.6% of all cardiovascular deaths and 55.2% at ages 45--54 was verified by autopsy. The autopsy rate of cardiovascular deaths in these two populations of deceased males (1) was in 1973 about three times higher than it had been 10 years earlier, (2) decreased significantly with the age of the deceased population, (3) was higher in urban than in rural areas, (4) was markedly higher in Helsinki than anywhere else in Finland (at ages 35--44 the rate in Helsinki was 94.9% and at 45--54 76.2% in 1973), (5) was dependent on the actual place of death, (6) was higher than the mean rate recorded for all natural deaths in these two groups of male deceased, (7) was higher in the category of cerebrovascular deaths and lower in deaths from ischaemic heart diseases than the mean rate recorded for all cardiovascular deaths, and (8) was composed mainly of medicolegal autopsies, when the cause of death was some ischaemic or functional heart disease; mostly a clinical autopsy was made when the death was due to some other category of CVD. In addition, 76% of the deceased 35--54-year-old males who died from CVD were either autopsied and/or treated in a hospital before death. This result and the quite high national autopsy rates among the deceased young and middle-aged populations give support to the reliability of the national mortality statistics at these ages.

Adult↗
PubMedDate not supplied

The A1 allele of the D2 dopamine receptor gene is associated with high dopamine transporter density in detoxified alcoholics.

The A1 allele of TaqI A restriction fragment length polymorphism (RFLP) in the D2 receptor (DRD2) gene locus has been suggested to be associated with low D2 receptor density in man. Striatal dopamine transporter (DAT) densities were studied with [(123)I]2-beta-carbometoxy-3beta(4-iodophenyl)tropane and single-photon emission tomography in 29 detoxified alcoholics, who were also genotyped for the two alleles of TaqI A RFLP at the DRD2 receptor gene locus. Alcoholics with the A1/A2 genotypes (n = 10) had statistically significantly higher DAT densities than subjects with the A2/A2 genotypes [n = 19; 8.0 +/- 1.2 (mean +/- SD) vs 6.9 +/- 1.1, P = 0.035]. We suggest that the TaqI A RFLP is in linkage disequilibrium with a gene variant modifying DAT density in alcoholics.

Adult↗
PubMedDate not supplied

Deviant auditory stimuli activate human left and right auditory cortex differently.

Infrequent "deviant' auditory stimuli embedded in a homogeneous sequence of "standard' sounds evoke a neuromagnetic mismatch field (MMF), which is assumed to reflect automatic change detection in the brain. We investigated whether MMFs would reveal hemispheric differences in cortical auditory processing. Seven healthy adults were studied with a whole-scalp neuromagnetometer. The sound sequence, delivered to one ear at time, contained three infrequent deviants (differing from standards in duration, frequency, or interstimulus interval) intermixed with standard tones. MMFs peaked 9-34 msec earlier in the right than in the left hemisphere, irrespective of the stimulated ear. Whereas deviants activated only one MMF source in the left hemisphere, two temporally overlapping but spatially separate sources, one in the temporal lobe and another in the inferior parietal cortex, were necessary to explain the right-hemisphere MMFs. We suggest that the bilateral MMF components originating in the supratemporal cortex are feature specific whereas the right-hemisphere parietal component reflects more global auditory change detection. The results imply hemispheric differences in sound processing and suggest stronger involvement of the right than the left hemisphere in change detection.

Acoustic Stimulation↗
PubMedDate not supplied

Non-invasive external regional measurement of cerebral circulation time changes in supratentorial infarctions using pertechnetate.

A method for measuring regional cerebral circulation time (rCCT) between the hemispheres using intravenous pertechnetate and a multidetector system is presented. Interhemispheric differences of rCCT instead of absolute values were selected because of the variation of pertechnetate bolus dispersion due to changes in the systemic circulation and injection technique inter-and intraindividually. Time activity curves over one minute were analyzed by a modified gamma function fitting method. The results are printed as a brain map which shows reference values and abnormal findings. Abnormal rCCT asymmetry was observed in 10 out of 77 controls (13%) and 58 out of 65 patients with cerebral infarction (89%). Within 2 weeks after a stroke shorter circulation time values on the side of the lesion than on the contralateral side were found in 5 patients. In the severe infarction cases and in the acute stages of infarction circulatory changes could be found in a great number of areas. In patients with manifest diabetes abnormal circulatory findings occurred in larger regions and in a greater number of the patients than in those without that disease. Although the luxury perfusion and diaschisis phenomena, as well as the influence of cross-over of the count rates between the hemispheres, reduce circulatory time differences, use of the present pertechnetate method allows detection of subtle regional circulatory changes in patients with brain infarction.

Adult↗
PubMedDate not supplied

Preoperative stereotactic hookwire localization of nonpalpable breast lesions with and without the use of a further stereotactic check film.

A series of 394 women underwent 399 stereotactically guided preoperative hook-wire localization of non-palpable breast lesions. 250 lesions were localized without checking the position of the needle tip with a further stereo film. Later the position of the localization needle was checked by means of a further stereo film in 149 lesions. If the needle tip was beside the lesion (failed x- or y-coordinates), we took a new stereo film. Errors in needle depth (z-coordinate) produced particularly subtle signs. Therefore a polystyrene phantom and a metallic object was used to ascertain how to recognize needle depth error on the stereotactic film. In 51 lesions readjustment of the needle depth was necessary. Measured by our criteria, successful and acceptable localization procedures with or without a check stereo-image film showed no significant differences. Unsuccessful localizations without the check film were significantly higher (16.0%) than with the check film, without readjusting the needle depth (7.1%) or after readjusting the needle depth (9.8%). These unsuccessful localizations were mostly architectural distortions or microcalcifications. Our results suggest that success of the localization procedure is better by using the stereo check film as without it, even in lesions which are difficult to resolve and target on films. However, readjustment of the needle depth did not always lead to successful localization.

Biopsy, Needle↗