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Biomedical subjects

A Otte

Publications and source records attributed to A Otte.

54 records · Page 3Linked to original sources
PubMed1997

Influence of spinal cord injury on cerebral sensorimotor systems: a PET study.

OBJECTIVES: To assess the effect of a transverse spinal cord lesion on cerebral energy metabolism in view of sensorimotor reorganisation. METHODS: PET and 18F-fluorodeoxyglucose were used to study resting cerebral glucose metabolism in 11 patients with complete paraplegia or tetraplegia after spinal cord injury and 12 healthy subjects. Regions of interest analysis was performed to determine global glucose metabolism (CMRGlu). Statistical parametric mapping was applied to compare both groups on a pixel by pixel basis (significance level P = 0.001). RESULTS: Global absolute CMRGlu was lower in spinal cord injury (33.6 (6.6) mumol/100 ml/min (mean (SD)) than in controls (45.6 (6.2), Mann-Whitney P = 0.0026). Statistical parametric mapping analysis disclosed relatively increased glucose metabolism particularly in the supplementary motor area, anterior cingulate, and putamen. Relatively reduced glucose metabolism in patients with spinal cord injury was found in the midbrain, cerebellar hemispheres, and temporal cortex. CONCLUSIONS: It is assumed that cerebral deafferentiation due to reduction or loss of sensorimotor function results in the low level of absolute global CMRGlu found in patients with spinal cord injury. Relatively increased glucose metabolism in brain regions involved in attention and initiation of movement may be related to secondary disinhibition of these regions.

Adult↗
PubMed1997

PET and SPECT in whiplash syndrome: a new approach to a forgotten brain?

Whiplash associated disorders are a medicolegally controversial condition becoming increasingly worrisome in the western world. This study was designed to evaluate perfusion and glucose metabolism in whiplash brain. Using Tc-99m-bicisate (ECD) single photon emission computed tomography (SPECT) and F-18-fluorodeoxyglucose (FDG) PET, six clinically and neuropsychologically controlled patients (patient group) with whiplash syndrome and 12 normal controls (control group) were investigated. Standardised elliptical regions of interest (ROIs) were determined in three adjacent transaxial slices in the frontal, parietal, temporal, and parieto-occipital cortex, cerebellum, brain stem, basal ganglia, and thalamus. For PET, the glucose metabolic index (GMI; =ROI uptake/global uptake at the level of the basal ganglia) and, for SPECT, the perfusion index (PI; =ROI/global) were calculated. In the patient group there was significant hypometabolism and hypoperfusion in the parieto-occipital regions (on the right (R) and left (L) side) compared with the control group: PET data: GMI parieto-occipital R: control 1.066 (0.081) (mean (SD)), patient 0.946 (0.065); P=0.0092, Mann Whitney. GMI parieto-occipital L: control 1.034 (0.051), patient 0.922 (0.073); p=0.0067. SPECT data: PI parieto-occipital R: control 1.262 (0.066), patient 1.102 (0.063); P=0.0039. PI parieto-occipital L: control 1.226 (0.095), patient 1.098 (0.075); P=0.0273. In some patients there was hypometabolism (>2 SD of control) in regions other than the parieto-occipital region. It is hypothesised that parieto-occipital hypometabolism may be caused by activation ofnociceptive afferent nerves from the upper cervical spine.

Adolescent↗
PubMed1997

[Influence of hormone substitution therapy on postmenopausal uterus].

In a 58-year-old postmenopausal woman blood flow and blood pool images of bone scintigraphy showed a focus of increased activity in the right pelvic region. Computed tomography and ultrasound exhibited no abnormalities in the abdomen; especially the uterus and ovaries were normal. Careful anamnestic evaluation revealed that the patient received a long-term peroral estrogen/gestagen replacement therapy for the prevention of osteoporosis, but did not have menstruation-like bleedings for the last twelve months of therapy. At time of admission, the patient was on day 25 of hormone replacement therapy, and the uterus was, therefore, in a premenstrual stage. Hence, despite cessation of bleedings in postmenopausal women, one should think of hormone replacement therapy as an explanation for vascular pelvic tumors seen by the first two phases of bone scintigraphy, before further diagnostic steps are undertaken.

Estrogen Replacement Therapy↗
PubMed1997

[Effect of thrombus endarterectomy (TEA) on the regional cerebral bloodflow (rCBF) in patients with unilateral internal carotid artery stenosis].

AIM: In a study of patients with unilateral and symptomatic stenosis of the internal carotid artery (ICA), the effect of endarterectomy (EA) on the regional cerebral blood flow (rCBF) was tested over a postoperative interval of 12 months. METHOD: Xenon-133-rCBF was assessed in 74 patients pre- and post-surgery (one week, six weeks, three months and 12 months after EA). This was done at rest and after stimulation with acetazolamide in order to test the perfusion reserve. RESULTS: Before surgery all 74 patients showed a diminished perfusion ipsilaterally-at rest and/or after stimulation. 38/74 (51%) patients had a significant (> 5%) and 36/74 (49%) patients a non-significant (< 5%) interhemispheric perfusion asymmetry. Twelve months after EA, there were only 23/74 (31%) patients with significant interhemispheric perfusion asymmetry. By stimulation, this decreasing effect became more evident: Before surgery 44/74 (60%) patients had a significant interhemispheric perfusion asymmetry, 12 months after surgery there were only 14/74 (19%) patients. CONCLUSION: In regard to the brain hemisphere distal to the ICA stenosis, our study revealed a significant improvement of brain perfusion after EA. Brain perfusion was stable over an interval of 12 months post-surgery. By EA, especially the perfusion reserve increased, as shown by a normal acetazolamide test. Hence, Xenon-133-rCBF could be shown to be an important method in the evaluation of the indication for surgery and of the result of it. In the intra-individual follow-up after EA, rCBF was able to identify hypoperfusion and may help decide, whether re-angiography is necessary or not.

Adult↗
PubMed1996

[Cerebral findings following cervical spine distortion caused by acceleration mechanism (whiplash injury). Assessment of current diagnostic methods in nuclear medicine].

In any grade of distortion of the cervical spine as a result of acceleration forces in addition to cervical symptoms cerebral symptoms like headache, vertigo, auditory disturbances, tinnitus, disturbances in concentration and memory, difficulties in swallowing, impaired vision and temporo-mandibular dysfunctions may appear. These symptoms can persist and become invalidating. Cerebral single-photon emission tomography (SPECT) and positron emission tomography (PET) enable new diagnostic horizons for neurotraumatology. In this article we summarize the actual findings of these nuclear medical methods in neuropsychologically deficient patients with distortion of the cervical spine as a result of acceleration forces. Especially the latest results of the group of Basle (University Hospital Basle, Clinic of Rehabilitation Rheinfelden, Switzerland) are illustrated. This group found parieto-occipital hypoperfusion by relative quantitation using SPECT and bicisate (Neurolite, ECD). A first pilot study using PET and F-18-fluoro-deoxyglucose (FDG) could verify the above observation. The group's working hypothesis is that parieto-occipital hypoperfusion may be caused by activation of nociceptive afferences from the upper cervical spine. A critical approach to interpreting new functional methods and, on the other hand, openness in new scientific findings may contribute to answering the lasting controversial medico-legal discussion with more objectivity.

Brain↗
PubMed1996

Bone mineral density in patients receiving suppressive doses of thyroxine for differentiated thyroid carcinoma.

To determine bone mineral density in patients with differentiated thyroid carcinoma receiving thyroxine replacement therapy in suppressive doses, we studied 65 patients (47 women and 18 men; age 25-83 years, mean+/-SD 52.5+/-15.4 years). Patients were free of thyroid cancer in clinical and laboratory examinations at the time of the study. Bone mineral density of the lumbar spine and both hips was measured by dual-energy X-ray absorptiometry. There was no decrease in bone density in either 32 postmenopausal or 15 premenopausal women compared with an age- and sex-matched control group, nor was any decrease in bone density found in men. Our data suggest that thyroxine treatment in suppressive doses in patients with differentiated thyroid carcinoma is not a risk factor for the development of osteoporosis.

Adult↗
PubMed1996

Parieto-occipital hypoperfusion in late whiplash syndrome: first quantitative SPET study using technetium-99m bicisate (ECD).

Brain single-photon emission tomography (SPET) with N,N''-1,2-ethylene-diylbis-L-cysteine diethyl ester dihydrochloride (ECD) was performed on ten patients with a clinically high grade late whiplash syndrome and on 11 controls. Two independent readers blinded to the clinical diagnosis were able to separate the ten patients from normal controls. All these patients had qualitative bilateral parieto-occipital hypoperfusion. To confirm this, the perfusion rate of parieto-occipital over global (perfusion index) was calculated after drawing elliptical regions of interest in transversal-oblique slices. The perfusion indices in patients were significantly lower than in controls as tested by the Mann-Whitney U test. This quantitative study proves our recent qualitatively analysed observation (Lancet 1995; 345: 1513- 1514).

Adult↗
PubMed1990

The Wnt-1 (int-1) oncogene promoter and its mechanism of activation by insertion of proviral DNA of the mouse mammary tumor virus.

Wnt-1 (int-1) is a cellular oncogene often activated by insertion of proviral DNA of the mouse mammary tumor virus. We have mapped the 5' end and the promoter area of the Wnt-1 gene by nuclease protection and primer extension assays. In differentiating P19 embryonal carcinoma cells, in which Wnt-1 is naturally expressed, two start sites of transcription were found, one preceded by two TATA boxes and one preceded by several GC boxes. In P19 cells, a 1-kilobase upstream sequence of Wnt-1 was able to confer differentiation-specific expression on a heterologous gene. We have investigated how Wnt-1 transcription was affected by mouse mammary tumor virus proviral integrations in various configurations near the promoters of the gene. One provirus has been inserted in the 5' nontranslated part of Wnt-1, in the same transcriptional orientation, and has functionally replaced the Wnt-1 promoters. Wnt-1 transcription in this tumor starts in the right long terminal repeat of the provirus, with considerable readthrough transcription from the left long terminal repeat. Another provirus has been inserted in the orientation opposite that of Wnt-1 into a GC box, disrupting the first Wnt-1 transcription start site but not the downstream start site. Most insertions have not structurally altered the Wnt-1 transcripts and have enhanced the activity of the normal two promoters.

Animals↗
PubMed1989

Going in circles.

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Hospital Bed Capacity, 500 and over↗
PubMed1985

Glucocorticoid receptors of normal and leukemic cells: role of proliferation conditions.

A published whole-cell binding assay of 3H-dexamethasone (3H-DEX) was combined with cell sedimentation analysis to investigate various factors influencing specific binding of glucocorticoids by leukemic lymphoblasts. Studies with mouse L1210 and human HL-60 cell lines revealed that glucocorticoid (GC) receptors accumulate during G1 phase of the cell cycle. In human lymphoblastic leukemia, the per cell receptor number was highest in cells in S and G2 phase and lowest in small, noncycling cells. In normal human white blood cells, GC receptor content was maximal in large lymphocytes and monocytes while no receptors were present in small lymphocytes. However, the receptor density of large lymphocytes was still 3-4 fold lower than of leukemic lymphoblasts of similar size. In L1210 cells the number of GC receptors decreased considerably in stationary cultures or following inhibition of cell cycle progression by dibutyryl cyclic AMP (dbc-AMP). Receptor content was also reduced in cells growing as ascites tumors in hosts with terminal disease. Accordingly, the receptor content in leukemic blasts appeared highly dependent on cell cycle distribution and on the proliferative status of the tumor cells. These findings may in part explain the large interpatient variation and the conflicting views regarding GC receptor content and prognosis in acute lymphoblastic leukemia.

Animals↗
PubMed1980

[A rare case of silent cholinesterase genetic variant (author's transl)].

Some patients present prolonged apnea following the administration of succinylcholine because of substantial portion of plasma cholinesterase (the enzyme responsible for the hydrolysis of this muscle relaxant) is present as an atypical variant. Up to the present four types of cholinesterase genes are known which combination can cause apnea to a greater or less extent. Silent homozygous EsEs present apnea of greatest duration due to the complete absence of cholinesterase activity. The case reported belongs to a family of four members and is an example of this extremely uncommon genetic variant, with a frequency of 1/170.000. To determine total cholinesterase activity genetic typing of the whole family was carried out utilizing the spectrophotometric technique of Szasz and Knedel with butirylthiocholine iodide as substrate. Inhibition studies were performed using benzoylcholine and dibucaine, sodium fluoride, scholine, and sodium chloride as inhibitors.

Adolescent↗
PubMed1979

[A case of succinylcholine apnea. Identification of genetic variants].

A report of a case of prolonged apnoea after succicurarium in a female patient with abnormal pseudo-cholinesterases is followed by a presentation of a study of pseudo-cholinesterases in 12 members of the family. The value of the use of 4 tests of inhibition of cholinesterase activity in determining the genotype of an individual is emphasised.

Apnea↗