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Biomedical subjects

K Rootwelt

Publications and source records attributed to K Rootwelt.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effect of nitroglycerin on cerebral circulation measured by transcranial Doppler and SPECT.

We used a combination of transcranial Doppler ultrasonography and single-photon emission computed tomography to noninvasively assess changes in the diameter of the middle cerebral artery induced by sublingual nitroglycerin in 10 healthy subjects. Nitroglycerin reduced mean blood flow velocities without concurrently changing regional cerebral blood flow in the perfusion territory of this vessel. Our results strongly suggest that nitroglycerin causes vasodilatation of the basal intracranial arteries.

Adult↗
PubMed1989

Encircling endocardial ventriculotomy for malignant ventricular arrhythmias. Effect on cardiac performance.

Cardiac performance and hemodynamics were studied with radionuclide ventriculography in 19 survivors of aneurysmectomy and encircling endocardial ventriculotomy for recurrent, sustained ventricular arrhythmia (group I). To characterize the effect of the ventriculotomy on cardiac function, comparisons were made with a similar group of patients who underwent aneurysm surgery for angina pectoris and/or congestive heart failure (group II). Functional classification revealed no difference between the groups and they achieved the same level of exercise after surgery. No intergroup difference was found postoperatively with respect to right or left ventricular ejection fraction, regional ejection fractions, peak ejection rate, cardiac index or stroke volume. Peak filling rate was also similar, as were cardiac volumes. Exercise did not change any parameter of this intergroup similarity. The authors conclude that most patients with moderately impaired left ventricular function who undergo left ventricular aneurysmectomy with encircling endocardial ventriculotomy do not differ in postoperative hemodynamics and systolic or diastolic function from those treated with simple aneurysmectomy.

Adult↗
PubMed1988

Neurological examination, computerized tomography, cerebral blood flow and neuropsychological examination in workers with long-term exposure to carbon disulfide.

Sixteen males, formerly exposed to carbon disulfide (CS2) for at least 10 years (mean 20 years), were administered a neurological examination, cerebral computerized tomography (CT), regional cerebral blood flow (rCBF) examination and neuropsychological examination. The clinical neurological examination revealed abnormalities in 15; cerebral CT showed signs of atrophy in 13; and neuropsychological examination indicated brain organic changes in 13. With the rCBF examination, slight abnormalities were found in 8. The findings indicate that long-term exposure to CS2 involves a risk of developing toxic encephalopathy, demonstrable on both neurological and neuropsychological examination. Furthermore, structural changes in the brain may be demonstrable by cerebral CT.

Brain↗
PubMed1988

Impairment in right ventricular performance after left ventricular aneurysm surgery.

To study the effect of operation for left ventricular (LV) aneurysm on right ventricular (RV) performance, we studied 50 patients before operation with right heart catheterization, RV angiography, and radionuclide ventriculography. Forty patients were followed up and underwent the same investigations 10 +/- 4 months after operation. At baseline, regional RV dysfunction was observed in 89% of the patients whereas global RV dysfunction was present in approximately a third. After operation, no changes in RV regional dysfunction or RV pressures were observed. However, a significant increase in RV end-diastolic (p less than 0.03) and end-systolic volume indices (p less than 0.02) along with a significant decrease in resting and exercise RV ejection fractions (p less than 0.05) was found. We were unable to demonstrate any significant relationship between preoperative RV dysfunction and surgical outcome. We conclude that RV dysfunction is common in patients with LV aneurysm. Current techniques of operative intervention for this type of aneurysm seem to be followed by RV dilatation and impairment in RV function.

Adult↗
PubMed1988

Serum thyroglobulin as a preclinical tumour marker in subgroups of thyroid cancer.

Serum samples from a biological serum bank taken several years before the diagnosis of cancer, were analysed for S-Tg and S-TSH in 43 patients with thyroid cancer and compared to 128 healthy controls matched for age, sex, geographical region and time of blood sampling. The main finding was the difference in S-Tg between cases and controls, the highest values being found in sera from cases. Relative risk of thyroid cancer increases with increasing S-Tg levels (the global test giving P less than 0.0005). Extremely high levels were found in 4 cases with follicular and 3 with anaplastic cancers. No such statistically significant difference was found in S-TSH concentration. Possible explanations for the elevated S-Tg observed several years before clinically evident malignant tumour are discussed.

Adult↗
PubMed1988

Improvement in cardiac performance and exercise tolerance after left ventricular aneurysm surgery--a prospective study.

Forty two patients were studied prospectively by rest and exercise radionuclide ventriculography before and after (10 +/- 4 months) left ventricular aneurysm resection. Functional classification (NYHA) improved from 3.0 +/- 0.6 to 2.3 +/- 0.5 (p less than 0.0001) with an increase in double product (p less than 0.01) and total exercise workload (p less than 0.04) over preoperative values. End-diastolic volume was significantly reduced (p less than 0.0001) and resting global left ventricular ejection fraction (LVEF) improved significantly (p less than 0.03) after surgery, as did regional ejection fractions of the lateral/inferior wall (p less than 0.01). Cardiac index (CI) at rest, however, remained unchanged. Under exercise, improvement of global (p less than 0.0003) and regional ejection fractions (p less than 0.02) was more pronounced and a significant increase was also observed for CI (p less than 0.003). Improvement in left ventricular performance occurred both in patients with single and multiple vessel disease, but was more distinct in the latter group who additionally received coronary artery bypass grafts. These patients were furthermore postoperatively able to increase global LVEF at exercise (p less than 0.05). We conclude that aneurysm resection with or without coronary bypass relieves cardiac symptoms and improves exercise tolerance and left ventricular function at rest and on exercise in most patients.

Adult↗
PubMed1988

Evaluation of a radioreceptor assay for TSH receptor autoantibodies.

A commercial radioreceptor assay for TSH receptor autoantibodies (TRAb), based on solubilized porcine receptor and purified radio-iodinated bovine TSH, was tested in 264 subjects with a variety of thyroid disorders. The sensitivity of the assay for the detection of hyperthyroid Graves' disease was 91%. The assay specificity for Graves' disease was 95%. With the exception of one patient with Hashimoto's disease and one patient with de Quervain's subacute thyroiditis no subjects other than Graves' patients had detectable TRAb. Thus purely blocking TSH receptor autoantibodies were not detected with the assay. One female with thyroxine-treated idiopathic primary hypothyroidism who had given birth to two children with transiently elevated TSH, was found to have a circulating TSH-binding substance that resulted in an abnormally negative TRAb value, and highly discrepant results when TSH was measured with a double antibody TSH radioimmunoassay and an immunoradiometric assay. The TSH-binding substance was precipitated like a protein, but was not IgG. Similar findings have not previously been reported.

Adolescent↗
PubMed1986

Herpes zoster ophthalmicus with cerebral angiitis and reduced cerebral blood flow.

Two patients with herpes zoster ophthalmicus (HZO) who experienced a delayed contralateral hemiparesis, the so-called crossed zoster syndrome, are described. Particular emphasis is paid to the cerebral blood flow (CBF) findings studied with the Xenon-133 inhalation technique using single photon emission computed tomography (SPECT). In a 40-year-old female with right-sided hemiparesis, angiography showed multiple segmental narrowings of the intracerebral arteries. Cerebral computer tomography (CT) scans were normal. The CBF studied 11 months after the HZO showed a generalized reduction of flow which, however, was more pronounced in the left hemisphere. On re-examination 8 months later both the mean hemispheric flow and regional CBF (rCBF) had increased to normal values. In a 66-year-old male with dysphasia and right-sided hemiparesis, cerebral CT scans demonstrated two small deep left-sided infarcts. CBF examination showed a generalized reduction of flow in the left hemisphere. The flow was slightly increased on re-examination 12 months later. These findings suggest that the Xenon-133 inhalation method represents a useful way to demonstrate the CBF pattern in this group of patients.

Adult↗
PubMed1986

Hereditary thrombocytopenia with excessively prolonged bleeding time, corrected by infusions of platelet poor plasma.

In a family with hereditary thrombocytopenia, transfused normal platelets as well as their own platelets had a shortened survival in the patients' circulation (11). On the other hand, the patients' platelets survived normally when transfused to a normal recipient. Platelet-associated immunoglobulins or circulating platelet antibodies were not detected (immunofluorescence method). About 200 ml platelet poor plasma (PPP) from each of 4 normal donors was infused daily for 5 consecutive d to 1 afflicted family member, causing a rise of platelet count from 65 X 10(9)/l to 163 X 10(9)/l and a decrease of bleeding time from 28 to 11 min 7 d after the PPP was discontinued. The platelet count then gradually decreased and was 65 X 10(9)/l with a bleeding time of 30 min 16 d after the PPP was discontinued. In a repeated PPP infusion experiment a similar response was evoked. It is concluded that the afflicted family members must have a deficiency of some plasma principle necessary to keep platelets fit and circulating.

Antibodies↗
PubMed1986

Measurement of aortic regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of aortic regurgitation, transmitral volumetric flow (MF) and left ventricular total stroke volume (SV) were measured by Doppler and cross sectional echocardiography in 23 patients without aortic valve disease (group A) and in 26 patients with aortic regurgitation (group B). The transmitral volumetric flow was obtained by multiplying the corrected mitral orifice area by the diastolic velocity integral, and the left ventricular total stroke volume was derived by subtracting the left ventricular end systolic volume from the end diastolic volume. The aortic regurgitant fraction (RF) was calculated as: RF = 1 - MF/SV. In group A there was a close agreement between the transmitral volumetric flow and the left ventricular total stroke volume, and the difference between the two measurements did not differ significantly from zero. In group B the left ventricular total stroke volume was significantly larger than the transmitral volumetric flow, and there was good agreement between the regurgitant fractions determined by Doppler echocardiography and radionuclide ventriculography. Discrepancies between the two techniques were found in patients with combined aortic and mitral regurgitation or a low angiographic left ventricular ejection fraction (less than 35%). The effective cardiac output measured by Doppler echocardiography accorded well with that measured by the Fick method. Doppler echocardiography provides a new and promising approach to the non-invasive measurement of aortic regurgitation.

Adolescent↗
PubMed1986

High-dose intravenous methylprednisolone pulse therapy as initial treatment in cryptogenic fibrosing alveolitis. A pilot study.

Ten patients with fibrosing alveolitis were treated in a simple random design initially with either a high dose of methylprednisolone (5 patients) or a conventional dose of prednisolone (5 patients) followed by a maintenance dose of 30 mg prednisolone daily. The patients were followed for 6 weeks. No significant (p greater than 0.05) differences were observed between patients with high and low initial dose of glucocorticosteroids, as regards forced vital capacity, transfer factor for carbon monoxide or symptom scores after 3 and 6 weeks of treatment. After 6 weeks the dyspnoea score and the 67Ga uptake decreased, on average, by 74 and 85%, respectively, while forced vital capacity and transfer factor increased by 15 and 29%.

Adult↗
PubMed1986

Changes in plasma and red cell volumes during exposure to high altitude.

Training at moderate altitude has been used by athletes to improve the performance at sea level. Not all athletes benefit from altitude training, and there also has been some doubt as to whether red cell volume increases in all subjects. Ten members of the Norwegian Everest Expedition 1985 took part in the present study. Plasma volume was determined by isotope dilution, using 125I-albumin. By simultaneous measurement of hematocrit the total blood volume and red cell volume were calculated. Measurements were done in Oslo (sea level) before departure, and in Base Camp (5300 m) four weeks later. The mean altitude during these four weeks was 4100 m. Red cell volume increased in all participants, and excessively in two of them. Since plasma volume decreased in four subjects, the change in total blood volume was less consistent. In one climber dehydration led to a decrease in total blood volume. While a significant correlation was found between maximal oxygen uptake and red cell volume at sea level, the hematologic response to altitude seemed independent on physical fitness. In one climber the erythropoietic response was so excessive (more than 50% increase in red cell volume), that he had to be hemodiluted.

Adult↗
PubMed1986

Reduced cerebral blood flow in high altitude climbers.

Cerebral blood flow (CBF) was studied by 133Xe inhalation dynamic single photon emission computer tomography in 8 members of a climbing expedition to the Himalayas. With one exception they had all previously climbed at high altitudes. All stayed above 6,500 m for approximately 3 weeks, and 5 reached the summit of Mt. Everest. CBF was measured in Oslo before, immediately after, and one year after the completion of the expedition. Measurements were made at rest and following the injection of 1 g acetazolamide intravenously. As reference group was used 13 healthy male subjects of similar age from the hospital staff. Ten age-matched male diving instructors formed a second control group. In the climbers a small, but not significant reduction in CBF was seen after the expedition. On the other hand, they had significantly lower CBF than reference subjects already before the expedition. The flow difference was most pronounced corresponding to the perfusion territory of the middle cerebral artery. One year after the completion of the expedition the average CBF in climbers was still more than 15% lower than in the reference group. The climbers had higher relative flow increase after acetazolamide injection than the reference subjects, showing that the functional capacity of the microvascular system of the brain was intact. Whether neuronal activity or number of neurones is reduced in climbers proportional to the decrease in flow, or maintained at normal level by increased oxygen and glucose extraction, cannot be answered by the present data.

Acclimatization↗
PubMed1986

Measurement of cerebral blood flow with 133Xe inhalation and dynamic single photon emission computer tomography. Normal values.

Cerebral blood flow (CBF) was studied by 133Xe inhalation tomography in 25 healthy subjects. Mean age was 41 years and range 23-66 years. Mean hemispheric CBF at rest was 59.8 ml/100 g/min, and cerebellar flow 60.8 ml/100 g/min. This difference was not statistically significant. The distribution of CBF values was skewed and approximated a log normal distribution. Estimated lower and upper normal reference range limits calculated as mean (log) +/- 2 S.D. (log) were 47-74 ml/100 g/min. Women had approximately 5 ml/100 g/min higher CBF values than men. This difference corresponded to the difference in hematocrit. Neither in men nor in women was there any tendency to age dependent reduction or increase in flow. In both sexes hemispheric regional CBF (rCBF) was asymmetric with higher flow values in the right cerebral hemisphere; particularly in the anterior distribution territory of the middle cerebral artery. In this region the maximum individual flow difference was 8 ml/100 g/min and the average difference 3.5 +/- 2.6 ml/100 g/min. Emotional activation as a consequence of the study conditions is assumed to be the cause of this observed asymmetry. Cerebellar flow was not assymetric. No significant difference in cerebellar or hemispheric CBF was found when a second study followed the first by 3-15 months. PCO2 correction of flow improved the reproducibility. The standard deviation of the flow difference between test/retest measurements was 5 ml/100 g/min. After 1 g acetazolamide given intravenously the mean increase in hemispheric CBF was 15.7 +/- 5.1 ml/100 g/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗