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Biomedical subjects

T Sørensen

Publications and source records attributed to T Sørensen.

At least 19 recordsLinked to original sources
PubMed1992

[Does diagnosed hypertension change quality of life? Results from a medical population study in Nord-Trøndelag].

The authors report results from medical screening for hypertension carried out on the entire adult population (aged greater than 20 years) of the county of Nord-Trøndelag, Norway. Previously undiagnosed hypertensives in need of medical treatment (n = 173), false positives (n = 233) and patients in need of continued blood pressure monitoring (n = 474) were followed up 10 to 36 months after the screening. This group was compared with a random population sample of known hypertensives (n = 206), patients previously treated for hypertension (n = 118) and normotensives (n = 2,326). No significant differences in changes in quality of life (subjective well-being) were observed between the two groups from screening to follow-up. However, negative events in life and chronic stresses other than the fact of becoming sick induced a deterioration of quality of life. Positive events induced an improvement in quality of life.

Adult↗
PubMed1992

[The diagnosis of hypertension--psychosocial consequences. A literature review of blood pressure examinations].

Several studies have shown higher rates of absenteeism from work among hypertensives who are aware of their condition than among hypertensives who have no such knowledge or among normotensives. This seems to be the result of labelling rather than of the hypertension itself. The results of studies of the effect of labelling and awareness on quality of life are ambiguous. Follow-up by health professionals in terms of reassurance and support often seems to alleviate adverse psychosocial effects of labelling.

Humans↗
PubMed1992

Ultrastructure of neurons containing somatostatin in the dentate hilus of the rat hippocampus after cerebral ischaemia, and a note on their commissural connections.

In a light microscopical study, we previously showed that more than 80% of somatostatin (SS) immunoreactive (-i) neurons in the hilus of the dorsal part of the rat dentate gyrus are lost 4 days after ischemia. In order to verify that the loss of SS immunostaining is due to an actual loss of the SS-i neurons and not merely a loss in expression of SS immunoreactivity, we have now performed an ultrastructural study of these neurons before and 40 h after 20 min of global cerebral ischaemia in adult rats. The normal SS-i neurons were multipolar and fusiform in shape. The SS-i product was associated with the endoplasmic reticulum and occasionally the Golgi apparatus. The cell nuclei had indentations of the nucleolemma and contained intranuclear rods. After ischaemia, many SS-i neurons in the dentate hilus showed increased electron density of both the cell nucleus and the cytoplasm. In addition the cytoplasm was heavily vacuolated with the SS-i associated with some of these vacuoles. Other SS-i neurons had, in addition to the vacuoles a more homogeneous, and abnormal electron lucent nucleus and cytoplasm. These ultrastructural changes correspond to previously reported irreversible, ischaemic cell changes of neurons. Based on this we conclude that the SS immunoreactivity in the dentate hilus of the dorsal hippocampus is lost after ischaemia because of neuronal necrosis. As a minor part of this study, we examined whether the ischaemia-susceptible SS-i neurons in dentate hilus had commissural axonal projections. This was done utilizing double fluorescence microscopy of retrograde axonal transport of the fluorescent dye, Fluoro-Gold, and the observation that vulnerable SS-i neurons display homogeneously dispersed immunostaining 40 h after ischaemia. Fluoro-Gold was injected unilaterally into the dorsal dentate gyrus 5 days prior to ischaemia. Then, 40 h after ischaemia, sections were stained for SS immunofluorescence, and examined, in the dentate hilus contralateral to the injection, for neuronal co-localization of both events. Cell counts revealed double-labelling of 13% of all neurons which displayed one of the events. This observation suggests that at least some of the ischaemia-susceptible SS-i neurons in dentate hilus do project commissurally. The pathophysiological significance of ischaemic loss of commissurally projecting SS-i neurons in dentate hilus remains to be determined.

Animals↗
PubMed1991

Leukocyte infiltration and glial reactions in xenografts of mouse brain tissue undergoing rejection in the adult rat brain. A light and electron microscopical immunocytochemical study.

Neural mouse xenografts undergoing rejection in the adult recipient rat brain were characterized with regard to infiltrating host leukocytes and reactions of graft and host astro- and microglial cells. Rejection occurred within 35 days with infiltration of the grafts by in particular macrophages and T-cells as well as blood-brain barrier (BBB) leakage for IgG. In the surrounding host brain microglial cells showed increased histochemical staining for nucleoside diphosphatase (NDPase) and increased immunocytochemical expression of complement receptor type 3 (CR3), while astroglial cells displayed an increased immunoreactivity for glial fibrillary acidic protein (GFAP). Light microscopic findings of rat major histocompatibility complex (MHC) antigen class I on microglial cells, endothelial cells and leukocytes were confirmed at the ultrastructural level and extended to include a few astrocytes. Rat and mouse MHC antigen class II was only detected on leukocytes and activated microglia. We suggest that host macrophages and activated host and xenograft microglial cells act in situ as immunostimulatory cells on T-helper cells, and that increased levels of donor MHC antigen class I may further enhance the killer activity exerted by host T-cytotoxic cells.

Acid Anhydride Hydrolases↗
PubMed1991

Detection of Clostridium perfringens type A enterotoxin in faecal and food samples using immunomagnetic separation (IMS)-ELISA.

A simple, rapid and sensitive immunoassay, based on immunomagnetic particles (Dynabeads M-280) was developed for detection and quantitation of Clostridium perfringens type A enterotoxin from faecal and food extracts. The assay had a detection limit of 2.5 ng/ml enterotoxin in homogenates of faeces and inoculated meat extracts. The specificity was confirmed by both crossed immunoelectrophoresis and Western immunoblotting techniques, using a purified enterotoxin as standard.

Animals↗
PubMed1991

A clinical comparison of optical and ultrasonic pachometry.

Central corneal thickness (CCT) of normal and oedematous corneae was measured in a study comparing a modified Haag-Streit optical pachometer and an ultrasonic pachometer (Teknar Ophthasonic, preset velocity 1630 m/s). Sixty-eight patients were examined before and after cataract extraction with implantation of an anterior chamber lens. Mean values of CCT before operation were 531 +/- 4.9 (SEM) micron by optical pachometry and 524 +/- 4.7 microns when measured by ultrasound (not significantly different). On the first post-operative day the values were 618 +/- 8.4 and 602 +/- 7.6 microns for optical and ultrasonic measurements, respectively (significantly different, 2P less than 0.001). Correlation analysis showed a high dependence between the methods with coefficients of correlation being 0.955 before and 0.958 after the operation. Linear regression analysis revealed small, but significant differences between the techniques. The difference between the two methods increased with increasing corneal hydration, whereas it could not be ascribed to sex, age, or intraocular pressure. It is concluded that for clinical purposes optical and ultrasonic pachometry techniques are comparable.

Aged↗
PubMed1990

[Conjunctival oxygen tension. Testing oxygen tension measurement of the conjunctiva].

A new apparatus which can measure oxygen tension and temperature in the conjunctiva was tested and compared with measurements of transcutaneous and arterial oxygen tension in eight volunteers in connection with normal oxygen tension, hypoxia and hyperoxia. In hypoxia, the conjunctival oxygen tension was found to be better correlated to and in better agreement with arterial oxygen tension than transcutaneous oxygen tension. The advantages with conjunctival oxygen measurements are continuous measurements in easily accessible and well vascularized tissue with the same arterial supply as the brain. In contrast to transcutaneous measurement, the new method does not require warming of the tissue as the conjunctiva is oxygen permeable.

Blood Gas Analysis↗
PubMed1990

Grafting of fetal CA3 neurons to excitotoxic, axon-sparing lesions of the hippocampal CA3 area in adult rats.

Hippocampal CA3 neurons from fetal rats were grafted to excitotoxic lesions in the CA3 subfield of the adult rat hippocampus and the formation of graft-host brain nerve connections examined. The excitotoxic lesions were induced by localized, stereotaxic injection of ibotenic acid (IA), a glutamic acid agonist, into CA3 of the dorsal hippocampus. The result was a so-called axon-sparing lesion with localized degeneration of nerve cells, but preservation of the extrinsic afferent fibers, now deprived of their targets. One week after the lesion a suspension of embryonic (E18-20) CA3 cells was grafted to the lesion site. Six weeks or more later the recipient brains were processed and analyzed by ordinary cell stains, histochemistry for acetylcholinesterase (AChE) and heavy metals (Timm staining), immunohistochemistry for the neuropeptides cholecystokinin and somatostatin and glial fibrillary acidic protein (GFAP) for astroglia, electron microscopy, and axonal tracing with retrogradely axonal transported fluorescent dyes or lesion-induced, anterograde degeneration combined with silver staining or electron microscopy. More than 90% of the grafts survived. They contained the normal types of CA3 neurons, which are mainly pyramidal cells, in addition to some normal, peptidergic, cholecystokinin- and somatostatin-reactive neurons. The grafts were innervated by AChE-positive, host cholinergic fibers, Timm-positive mossy fiber terminals from the host fascia dentata, and host commissural fibers traced by axonal degeneration. Efferent transplant projections were traced to the ipsilateral host CA1 (Schaffer collaterals) and the contralateral host hippocampus by retrograde axonal transport of fluorochromes injected into these host brain areas. All grafts analyzed by electron microscopy contained axonal varicosities resembling axonal growth cones even after long survival times. The results demonstrate that fetal rat hippocampal neurons, grafted to excitotoxic, axon-sparing lesions in the adult brain, can become both structurally and connectively well incorporated in the mature host central nervous system.

Animals↗
PubMed1990

Hypertension labelling, life events and psychological well-being.

Almost all previous studies of the psychological sequelae of hypertension labelling have lacked a prospective, longitudinal design which could allow for causal interpretations. The present study relies on questionnaire data from a hypertension screening carried out on the entire adult population of a medium-sized, Norwegian county (total number of participants = 74977). 'Labelled' individuals, i.e. previously unaware hypertensives (N = 173), false positives (N = 233), and patients in need of continued BP control (N = 474) have been followed up after 1-3 years, and comparisons are made with aware hypertensives (N = 206), patients previously treated for hypertension (N = 118), and a random sample of normotensives (N = 2326). 'Pre-labelling', baseline measures of subjective well-being had been carried out on all comparison groups in connection with the screening. Changes in psychological well-being are not significantly related to labelling or BP-status. However, there is a deterioration in psychological well-being among participants who have been subjected to one or more negative life events/stresses (other than labelling) in the preceding 12 months.

Adaptation, Psychological↗
PubMed1990

Neural grafting to ischemic and excitotoxic, hippocampal lesions in the adult rat.

Results of neural grafting to excitotoxic and ischemic lesions of the adult rat hippocampus is reviewed with particular emphasis on the exchange of host-transplant nerve connections. Based on observations obtained by a variety of tracing techniques about 6 weeks after--(i) grafting of pieces of neonatal fascia dentata to one week old ibotenic acid lesions of the adult rat fascia dentata, (ii) grafting of suspensions of late fetal CA3 cells to one week old ibotenic acid lesions of the adult rat CA3--and (iii) grafting of suspensions of late fetal CA1 cells to one week old ischemic lesions of the adult rat CA1, we conclude that axon-sparing lesions of the mentioned types enhance the growth of adult host brain axons of the so called point-to-point type into neural grafts. We interpret these findings as the result of an improved capability of adult host brain axons to participate in the graft host interaxonal competition for synaptic sites in the developing neural grafts. At the same time an extensive growth of graft CA3 and CA1 axons into the host brain was demonstrated.

Animals↗
PubMed1989

[Addiction to drugs and alcohol among physicians and nurses].

A retrospective investigation based on case reports was undertaken concerning abuse of alcohol and drugs among medical staff, 44 doctors and 23 nurses, who were treated in the Department of Psychiatry, Rigshospitalet during the period 1970-1982, all of whom received treatment for more than six months. By the end of 1987, a marked excessive mortality was found and this was greatest among doctors among whom 50% had died with an average age of 45.5 years. Factors which were found to be of significance for the prognosis for duration of survival in this selected material were 1) duration of the abuse of medicine, 2) presence of mixed alcohol and drug abuse and 3) previous suicidal attempts.

Adult↗