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Biomedical subjects

B Sonesson

Publications and source records attributed to B Sonesson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Tyrosinase activity in the serum of patients with malignant melanoma.

We have recently described a new method for measurement of tyrosinase activity in small amounts of human serum (100 microliters), where the purification of tyrosinase is obtained by adsorption of the enzyme to concanavalin A sepharose. The method, which measures stereospecific dopa oxidation, was used in the winter of 1992-93 for the measurement of activity in serum obtained from 30 healthy subjects and from 10 patients with melanoma metastases. The serum tyrosinase values in the 30 subjects ranged from 0.1 to 1.0 nkatal/l, and the mean value and standard deviation was 0.4 +/- 0.2 nkatal/l. In the 10 patients with melanoma, the tyrosinase serum values ranged from 1.1 to 10.6 nkal/l, and the mean value was 3.1 nkatal/l.

Adult↗
PubMed1995

Spatial and perceptual impairment related to cortical cerebral blood flow and EEG in deep white matter infarcts of the right hemisphere.

A study was performed in order to investigate how infarcts located in the white matter of the right hemisphere may affect processing of spatial and perceptual abilities. A battery of neuropsychological tests was applied to 7 right-handed patients with CT-verified infarcts of the right internal capsule or periventricular white matter. Examinations were performed 1-3 weeks post stroke and 3-7 months later. The patients were assessed by neurological examinations, EEG, and cortical regional cerebral blood flow (rCBF) measurements. This study suggested that deep white matter infarcts of the right hemisphere may result in persistent spatial impairment in the absence of decreased cortical rCBF. Perception was disturbed in cases of low mean cortical CBF of both hemispheres.

Adult↗
PubMed1995

Seasonal variation of tyrosinase activity in serum.

Serum samples for the analysis of tyrosinase activity were obtained from 10 healthy subjects in autumn, winter and summer. Tyrosinase was purified from 100 microl serum by adsorption to concanavalin A sepharose, the tyrosinase adsorbed to the gel being separated from other components by centrifugation. The gel was suspended in a buffer containing 5-hydroxy-indole-3-acetic acid as an antioxidant and incubated for 2 min with L-cysteine and D-L-dopa at 37 degrees C. The 5-S-L-cysteinyl-L-dopa formed was measured by HPLC and electrochemical detection. Tyrosinase has high stereo-specificity for the L-enantiomer of dopa, and correction for non-specific oxidation was made by simultaneous measurement of 5-S-L-cysteinyl-D-dopa formed from D-dopa. Whereas the oxidation of L-dopa catalysed by tyrosinase ws inhibited by L-tyrosine, the non-specific oxidation of D-dopa was not. Mean serum tyrosinase activity was 0.9 nkatal/l in summer, 0.8 nkatal/l in autumn and 0.4 nkatal/l in winter. The range of tyrosinase activity was much higher in summer and autumn than in winter.

Chromatography, High Pressure Liquid↗
PubMed1994

The anatomy of the iliolumbar ligament.

During routine autopsies and anatomical dissections the anatomy of the iliolumbar ligament was studied and determined. In previous studies and literature, the ligament has been described to consist of three to five parts. We found the ligament to consist of only two parts: the anterior part and the posterior part, both attaching to the L5 transverse process. The insertion of the ligament has also been mentioned previously as attaching to the iliac crest. Both parts of the ligament were found to inset to the upper part of the iliac tuberosity, significantly lower than the iliac crest. The iliolumbar ligament cannot be visualized from the dorsal side before dissecting through all the lower back muscles and their fascias. We also found no evidence of any ligament part attaching to the L4 transverse process.

Adolescent↗
PubMed1994

Differences in mechanical properties of the common carotid artery and abdominal aorta in healthy males.

PURPOSE: Vascular disease is differentiated throughout the vascular regions, with central arteries more prone to dilation and with peripheral arteries more prone to occlusive disease. In this study we investigated the diameter and compliance in the common carotid artery and abdominal aorta in healthy males at varying ages to assess potential differences in the aging process. METHODS: An ultrasound phase-locked echo-tracking system was used to determine differences in diameter and pulsatile diameter changes of the common carotid artery and abdominal aorta in 56 healthy Caucasian males ages 10 to 74 years. Pressure strain elastic modulus (Ep) and stiffness (beta) were calculated from diameter, pulsatile diameter change, and blood pressure obtained by the auscultatory method. Compliance was defined as the inverse of Ep and stiffness. RESULTS: The diameter of both common carotid artery and abdominal aorta increases not only when a person is a child, but also when they are between 25 and 70 years old. The dilation in adults seems to be more accentuated in the abdominal aorta (27%) than in the common carotid artery (17%). Ep and stiffness (beta) are higher in the common carotid artery when a person is 10 years of age (p < 0.01 and 0.05). However, during aging, Ep and stiffness (beta) increase to a higher extent in the aorta than in the common carotid artery, with a significantly higher Ep and stiffness (beta) in the aorta when a person is 45 years and older (45 years: p < 0.05 and p = NS; 60 years: p < 0.001 and p < 0.001; 70 years: p < 0.01 and p < 0.01). CONCLUSIONS: This investigation demonstrates regional differences in diameter change and compliance in the common carotid artery and abdominal aorta and implies that the abdominal aorta is more prone to degenerative changes than the common carotid artery. This may be one etiologic factor for the regional differences in vascular disease.

Adolescent↗
PubMed1994

Sex difference in the mechanical properties of the abdominal aorta in human beings.

PURPOSE: A previous study has shown age- and sex-related differences in abdominal aortic compliance. In that study blood pressure determined by auscultation in the brachial artery was assumed to be equal to blood pressure in the abdominal aorta. To validate our findings we investigated the pressure-diameter (P-D) relationship of the abdominal aorta. METHODS: Diameter and pulsatile diameter change of the abdominal aorta were determined noninvasively by an ultrasound phase-locked echo-tracking system with simultaneous measurement of aortic pressure resulting in P-D curves in 27 healthy male and female volunteers 23 to 72 years of age. The degree of error in aortic compliance as calculated from blood pressure determined by auscultation of the brachial artery rather than from direct measurement of aortic pressure was evaluated. Compliance was defined as the inverse of pressure strain elastic modulus (Ep) or of stiffness (beta). RESULTS: There was no significant difference in the systolic pressure at the two sites, but the diastolic pressure was systematically overestimated by approximately 10 mm Hg when determined by the auscultatory method (p < 0.01) leading to a 15% to 20% underestimation of Ep and stiffness (beta). The individual P-D curves exhibited hysteresis, were nonlinear, and revealed that the aorta is more distensible at lower than at higher pressures. The steepness of the P-D curve decreased with increasing age and this occurred at an earlier age in men than in women. CONCLUSION: This investigation demonstrates a decrease in abdominal aortic wall distensibility with age, which occurs at an earlier age in men, and confirms earlier results by use of the indexes Ep and stiffness (beta). This implies that the abdominal aorta in men is more prone to degenerative changes, which may be one of the factors responsible for the sex difference in aortic vascular disease.

Adult↗
PubMed1994

Infrarenal aortic diameter in the healthy person.

In order to determine the relevance of abdominal aortic dilatation, knowledge of the normal aortic diameter and its relation to age, sex and body size (height, weight, body surface area) is essential. The diameter of the infrarenal aorta was measured in 146 healthy males and females 4-74 years old with ultrasonography and the influence of the aforesaid factors on aortic diameter was analysed by means of a multiple stepwise regression model. The infrarenal aorta was found to increase steadily in diameter throughout life. From about 25 years the diameter was larger in males than in females (p < 0.01) though this difference vanished if corrected for differences in body surface area. Significant correlations were found between aortic diameter and weight (r = 0.84, p < 0.001), height (r = 0.77, p < 0.001) and body surface area (r = 0.83, p < 0.001). Age followed by body surface area were the factors most influencing aortic diameter in both males (r = 0.92, p < 0.001) and females (r = 0.94, p < 0.001). Nomograms predicting aortic diameters in relation to age, sex, and body surface area are presented.

Adolescent↗
PubMed1994

Abnormal mechanical properties of the aorta in Marfan's syndrome.

OBJECTIVES: Aortic dilatation, dissection and rupture are among the major causes of death in subjects with Marfan's syndrome. The aim of the study was to investigate the mechanical properties or compliance of the aorta in these subjects and compare them with a healthy age- and sex-matched reference population. MATERIALS AND METHODS: An ultrasound phase-locked echo-tracking system was used to determine diameter and pulsatile diameter change of the infrarenal aorta in nine subjects with Marfan's syndrome which were then compared with the values for 165 healthy individuals. Compliance, defined as the inverse of Ep (pressure strain elastic modulus) or stiffness (beta), was calculated from pulsatile diameter change and blood pressure obtained by the auscultatory method with a sphygmomanometer. For statistical analysis confidence intervals (95%) obtained from the healthy controls were used for comparison. Analysis of covariance (ANCOVA) was performed for the female patients. The sample size for males (n = 2) was too small for the latter analysis. RESULTS: Compared with normal subjects and their confidence intervals, subjects with Marfan's syndrome had an increased Ep and stiffness (beta) and decreased strain (fractional diameter change) in the infrarenal aorta. Furthermore, ANCOVA in the female patients showed increased beta (p < 0.01) and Ep (p < 0.01) and a decreased strain (p < 0.001). Aortic diameters, MAP, as well as the pulse pressure, were similar in the two groups. CONCLUSION: This investigation demonstrates alterations in the mechanical properties of the aorta in Marfan's syndrome in the form of increased stiffness of the aortic wall. This may be of importance in the pathogenesis of aortic dissection and rupture.

Adolescent↗
PubMed1993

Compliance and diameter in the human abdominal aorta--the influence of age and sex.

OBJECTIVES: Females develop cardiovascular diseases and abdominal aortic aneurysms later in life than males. In this study we investigated the diameter and compliance of the distal abdominal aorta in healthy females of varying ages. The results were compared with those obtained previously from healthy males in order to assess potential sex-related differences in the aging process of the abdominal aorta. METHODS: An ultrasound phase-locked echo-tracking system was used to determine differences in diameter and pulsatile diameter change of the distal abdominal aorta in 69 Caucasian females from 4 to 74 years. Pressure strain elastic modulus (Ep) and stiffness (beta) were calculated from diameter, pulsatile diameter change and blood pressure obtained by the auscultatory method. Compliance was defined as the inverse of Ep and beta. The pressure dependence of Ep and beta was evaluated in 10 females with intraarterial blood pressure measurement at rest and during isometric exercise. RESULTS: The diameter of the distal abdominal aorta increased not only in the period between the ages of 5 and 25 years, but also by about 24% between 25 and 70 years (p < 0.0001). From about the age of 25 years the diameter was smaller in females than in males (p < 0.01). Ep and beta increased nearly linearly with advancing age in females from 0.18 x 10(5) to 1.17 x 10(5) N/m2 (Ep) and from 1.85 to 8.51 (beta). In males the increase in Ep and beta was greater and exponential in nature (p < 0.001). Ep but not beta increased significantly during blood pressure increase (p < 0.05). Stiffness (beta) may therefore be a more useful index of arterial compliance than Ep. CONCLUSIONS: This investigation demonstrates age and sex-related differences in diameter and compliance in the normal human abdominal aorta and implies that degenerative changes appear later in females than in males.

Adolescent↗
PubMed1993

Non-invasive measurement of pulsatile vessel diameter change and elastic properties in human arteries: a methodological study.

A recently developed ultrasound phase-locked echo-tracking system makes it possible to measure non-invasive pulsatile vessel diameter changes, and, in combination with blood-pressure measurement, to calculate pressure strain elastic modulus (Ep) and stiffness (beta). The reproducibility in measurements of pulsatile diameter changes with this system was evaluated. Also the precision of indirect blood-pressure measurements, as compared to the simultaneously measured intra-arterial blood pressure was tested. The resulting reproducibility in pressure strain elastic modulus (Ep) and stiffness (beta) was evaluated. Intra-observer variabilities in measuring pulsatile diameter changes were 16% for the abdominal aorta, 10% for the common carotid artery, and 15% for the common femoral artery, respectively. Intra-observer variabilities for Ep and beta were 21% for both in the abdominal aorta, 17% for both in the common carotid artery, and 18% for both in the common femoral artery, respectively. There were only small differences in indirect and direct measurement of systolic blood pressure, whereas indirect blood pressure measurement systematically overestimated the diastolic blood pressure, on average by 20%. The variabilities in indirect blood pressure measurements were 2% for the systolic and 3% for the diastolic blood pressure, respectively. Inter-observer variability in the investigation of the common carotid artery was 10% for the pulsatile diameter changes, and 21% and 23% for Ep and beta, respectively. Thus, the echo-tracking system represents a reliable system for estimation of pressure strain elastic modulus and stiffness. However, Ep and beta are systematically underestimated by 25-30%, when used in combination with indirect blood pressure measurements.

Adult↗
PubMed1992

Prevalence of abdominal aortic aneurysm in the offspring of patients dying from aneurysm rupture.

The prevalence of abdominal aortic aneurysm (AAA) is high in the brothers of patients with aneurysm. A genetic component in the development of AAA has, therefore, been postulated. In this study the offspring of patients who had died from AAA rupture were invited to undergo ultrasonography of the abdominal aorta. The attendance rate was 69 per cent. Thirty-nine sons of median age 60 (range 45-75) years and 23 daughters of median age 62 (range 42-80) years were examined. Abdominal aortic dilatation was found in eight men and one woman. The presence of aortic dilatation in these nine cases was not related to age, hypertension, smoking or symptoms of occlusive arterial disease. It is concluded that the sons of those who have died from ruptured AAA constitute a high-risk group for the development of this condition and should be considered for further screening.

Aged↗
PubMed1992

Clinical outcome and cognitive impairment in patients with severe head injuries treated with barbiturate coma.

This study reports on clinical outcome in 38 patients with severe head injuries (posttraumatic coma for 6 hours or more) treated with barbiturate coma because of intracranial hypertension. Eighteen patients died, 4 patients remained in a severely disabled or a chronic vegetative state, and 16 patients reached the levels good recovery/moderate disability. Six of these patients returned to work or school full time, 4 for half time and 3 were in a rehabilitation program. Fourteen patients were subjected to a comprehensive neuropsychological assessment. All patients except one exhibited varying degrees of cognitive dysfunction and 6 patients had signs of personality change. The quality of life for the majority of surviving patients was relatively good but the positive effects of barbiturate coma therapy in the age groups over 40 years appeared to be limited.

Adult↗
PubMed1992

Noninvasive measurement of diameter changes in the distal abdominal aorta in man.

An ultrasound phase-locked, echo-tracking system was used to determine the dynamic properties of the distal abdominal aorta in 10 Caucasian male subjects (mean age, 25 years). Recordings were made at rest and during the blood pressure increase resulting from isometric exercise. The pressure diameter curve was nonlinear with an inflection at about 90-110 mmHg. Above this pressure range, the vessel was stiffer (less compliant), but the pressure diameter relationship was roughly linear above as well as below the inflection. Individual pressure diameter curves showed hysteresis, i.e., the aorta had a smaller diameter during expansion than during retraction at corresponding pressures. The pressure strain elastic modulus (Ep) and stiffness (beta) were at rest [Mean Arterial Pressure (MAP), 81 mmHg] 0.70 10(5) N/m2 and 6.0, respectively. During isometric exercise (MAP, 122 mmHg), Ep increased significantly by 91% and stiffness (beta) nonsignificantly by 27%. The variability of the compliance determinations was 5% when the ultrasonic system was combined with intra-arterial blood pressure measurements and less than 7% when combined with auscultatory blood pressure measurements. It is concluded that the phase-locked, echo-tracking system fulfills clinical requirements for routine measurements of vascular compliance.

Adult↗
PubMed1992

Diameter and compliance in the male human abdominal aorta: influence of age and aortic aneurysm.

In this study changes in the diameter and compliance of the distal abdominal aorta (76 healthy Caucasian males, 5-71 years old) were determined non-invasively and related to age by means of an ultrasound phase-locked echo-tracking system. The diameter of the aorta increased not only in the period between 5 and 25 years of age, but also by about 30% between the ages of 25 and 71. The pressure diameter curves at 25, 51 and 70 years were non-linear with flattening between 90 and 110 mmHg, and the slope of the curves declined with age. Thus, the pressure strain elastic modulus (Ep) and stiffness (beta) increased (i.e. compliance decreased) in an exponential manner according to age. A group of 37 males with aneurysmal widening of the distal abdominal aorta had a significant increase in Ep when compared to an age-matched control group. Furthermore, the ranges for both Ep and beta were much larger in the aneurysm group than in the control group, indicating diversity in the pathogenesis of the disease. The non-invasive ultrasonic method of phase-locked echo-tracking is an appropriate method for studying compliance in major arteries under a variety of pathophysiological conditions.

Adolescent↗
PubMed1989

Late magnetic resonance imaging related to neurobehavioral functioning after aneurysmal subarachnoid hemorrhage.

Twenty patients who underwent early aneurysm surgery--that is, surgery within 72 hours after rupture--underwent further follow-up examination including magnetic resonance imaging (MRI) of the brain and a comprehensive neuropsychological assessment. Significant statistical correlation between tissue loss as seen on a late MRI scan and neurobehavioral deficits could not be established. Among 9 patients with no tissue loss seen on MRI, 3 exhibited substantial cognitive dysfunction and 6 had mild impairment. Three patients showed minor but corresponding tissue loss and deficits. In 3 patients with pronounced pathological indications on MRI, evidence of cognitive dysfunction was absent in 2, and 1 patient showed substantial impairment. The remaining 5 individuals displayed moderate pathological indications on MRI, with no obvious correspondence to cognitive functioning. In 7 patients, small white matter lesions, probably silent infarcts not seen on computed tomographic scan, were discovered on MRI. There was a clear relationship between arterial hypertension prior to aneurysm rupture and the extent of tissue loss seen on MRI. Absence of pathological findings on MRI scan did not exclude cognitive malfunctioning, and vice-versa.

Adult↗
PubMed1989

Cognitive functioning after subarachnoid haemorrhage of unknown origin.

Twenty patients, who had sustained a proven subarachnoid haemorrhage (SAH) and in whom cerebral panangiography had failed to reveal any source of the bleeding (SAH-NUD), were subjected to a neuropsychological examination involving memory functions, spatial perceptual organization, visuoconstructive abilities, reasoning, perceptual speed and accuracy, and concept formation. Cognitive functioning in SAH-NUD patients was compared with normal reference values and also related to the cognitive performance of neurologically intact patients having sustained an aneurysmal bleeding (SAH-AN). SAH-NUD patients showed significant reduction of verbal learning and retention, and of abilities involving abstract attitude and concept formation, i.e., functions related to frontotemporal structures. In all other respects the performance of these patients approached normality. Unexpectedly, there were no significant differences in mean test scores separating SAH-NUD from aneurysmal SAH patients. Collapsing the patient groups produced an increased number of significant deviations from normality, which was interpreted as the effect of the contribution of a greater number of relatively more impaired SAH-AN patients. This was supported by the finding that the ratio of impaired individuals to total number of subjects differed in the groups; the proportion of individuals showing cognitive sequelae was larger among SAH-AN patients throughout all comparisons but one. Although SAH of unknown aetiology represents much less of a catastrophe as compared with haemorrhage of aneurysmal origin, it does not preclude cognitive disturbances. Thus, the presence of blood per se anywhere in the subarachnoid spaces appears to affect higher brain function(s).

Adolescent↗
PubMed1989

Spatial impairment following right hemisphere transient ischaemic attacks in patients without carotid artery stenosis.

Neuropsychological testing was performed on: 10 right-handed patients who had had 1-4 right hemisphere transient ischaemic attacks (TIAs), 10 normal controls, 10 house painters with long-term exposure to organic solvents, and 10 patients with liver cirrhosis. The subjects in each group were matched for age and education. No TIA patient had significant internal carotid artery stenosis, and CT was normal except in one patient, although magnetic resonance imaging (MRI) performed 3 years after the testing was abnormal in 4/8 cases. No patient reported additional distinct TIAs during the period between neuropsychological testing and MRI. The TIA patients showed lateralized signs of spatial impairment, whereas the cirrhotics and also (but to a lesser degree) the house painters showed signs of diffuse cerebral dysfunction. The study shows that hemispheric TIAs in patients without significant internal carotid artery stenosis may result in persistent focal cognitive impairment. This can be demonstrated with sensitive neuropsychological instruments even when MRI is normal.

Aged↗