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Biomedical subjects

K Bergström

Publications and source records attributed to K Bergström.

At least 127 records · Page 7Linked to original sources
PubMed1986

Magnetic resonance imaging of cerebral compression and local brain tissue water content during continuous extradural bleeding. An experimental study in dogs.

Continuous recording of vital physiologic parameters and magnetic resonance imaging were performed during progressive extradural bleeding in spontaneously ventilated anesthetized dogs. The volume of the bleeding could exceed the intracranial volume by 500 per cent due to the formation of an extradural arteriovenous shunt. The rate of hematoma growth was dependent on the area of stripped dura. Midline shift, herniation and lateral ventricle compression occurred early, corresponding to changes in vital parameters. Local brain water increased non-linearly with white matter preceding gray matter. Water increase started first in the ipsilateral hemisphere followed by the contralateral hemisphere, brain stem and cerebellum. The correlation between local tissue water increase and local perfusion pressure supports the notion of an ischemic brain edema being formed during an extradural bleeding.

Animals↗
PubMed1986

Evaluation of intracranial pressure rebound after evacuation of intracranial expanding lesions. An experimental study in dogs.

Sequential magnetic resonance imaging was used to follow brain displacement, signs of herniation and increase in local brain tissue water content during expansion and after evacuation of an extradural balloon in anesthetized, artificially ventilated dogs. A fatal intracranial pressure (ICP) rebound occurred if the cerebral perfusion pressure (CPP) was critically reduced to 20 mm Hg for more than half an hour. Despite reduction of brain displacement after balloon evacuation brain water content continued to increase. Compression of CSF outflow pathways and signs of herniation remained. CPP continuously fell to zero. ICP rebound is a grave situation significantly influenced by a large increase in brain tissue water.

Animals↗
PubMed1986

In vivo measurement of dopamine receptors in pituitary adenomas using positron emission tomography.

Patients with pituitary adenomas were examined with positron emission tomography (PET) with the administration of the 11C-labelled dopamine-D2 antagonists N-methylspiperone and raclopride. The studies were repeated after protection of the D2-receptors with Haloperidol to enable a separation of specific and unspecific receptor binding. The receptor binding was evaluated by visual inspection and with the application of a kinetic model. The results showed marked specific dopamine-D2 receptor binding in the prolactinomas and minimal or no such binding in the hormonally inactive adenomas. The two tracers 11C-raclopride and 11C-N-methylspiperone showed qualitatively the same result although raclopride resulted in a higher tumor to normal brain ratio. In conclusion, PET is a valuable complement to other radiologic techniques like computed tomography and magnetic resonance imaging in the evaluation of pituitary adenomas. An assessment of the dopamine-D2 receptors in the adenomas has a direct influence on the choice of treatment because adenomas with high amounts of receptors are in most cases effectively treated with dopamine agonists like bromocriptine.

Adenoma↗
PubMed1986

Amino acid metabolism in pituitary adenomas.

Patients with pituitary adenomas were examined with positron emission tomography with the administration of 11C-labelled methionine. In a few patients comparative studies using the two stereo-isomers L- and D-methionine were also performed. The results showed a rapid distribution of D-methionine within the tumor tissue without signs of irreversible trapping of the tracer. L-methionine on the other hand was rapidly irreversibly trapped indicating the metabolic fate. It is concluded that 11C-L-methionine can be used to quantify amino acid metabolism in the tumors. The amino acid metabolism was evaluated in a group of adenomas before and after treatment with bromocriptine. The results indicate a marked reduction of the amino acid metabolism in prolactinomas amounting to 60%. These tumors at a later time responded with tumor shrinkage. Hormonally inactive tumors showed no effect of treatment.

Adenoma↗
PubMed1986

Subtraction in magnetic resonance imaging.

Subtraction of images recorded with multiple echo, spin echo (SE) techniques was performed in phantom and clinical studies of patients with pituitary adenomas and gliomas. The tissue differentiation was enhanced in the subtracted images.

Adenoma↗
PubMed1986

Magnetic resonance imaging of stereotactic radiosurgical lesions in the internal capsule.

Confirmation of radiosurgical lesions in white matter has earlier been difficult to obtain, which has hampered the evaluation of clinical outcome in relation to the site and the size of the lesions. In this investigation 7 consecutive patients subjected to bilateral stereotactic gamma capsulotomy for intractable anxiety disorders were re-examined several years after treatment. The protocol included both magnetic resonance imaging (MRI) and computed tomography (CT) interpreted under blind conditions and prospective psychiatric evaluations performed by two independent evaluators who had not been involved in the selection and the treatment of the patients. The lesions were clearly visible with MRI in all patients who improved after treatment. MRI proved to be more accurate than CT both in detecting and in defining the size and the configuration of the lesions. The extent of the tissue reaction following the irradiation seemed to be best defined in T2 weighted images. A high correlation (p less than 0.01) was obtained between ratings of clinical outcome and radiosurgical precision as reflected by MRI. It is concluded that MRI may provide the clinician with more information than CT does. In the future MRI may also facilitate the determination of a radiation threshold value for white and grey matter lesions and provide a more detailed knowledge of the time course of the development of such lesions.

Adult↗
PubMed1985

A human pharmacological study comparing conventional heparin and a low molecular weight heparin fragment.

The pharmacokinetics of a heparin fragment of low molecular weight (LMWH) of 4000-5000 D and unfractioned standard heparin (UFH) have been studied after i.v. injections of different doses and infusions in 8 humans. The heparin activity was significantly higher and the effect on APTT lower after LMWH fragment as compared to UFH in the same doses. The half-life of heparin activity was about 1 hr for UFH and about 2 hr for LMWH. LMWH was found to be eliminated according to first order kinetics and there were no signs of dose dependency.

Adult↗
PubMed1985

Orally administered ketoconazole rapidly appears in seminal plasma and suppresses sperm motility.

Ketoconazole has been shown to exert spermatostatic effects in vitro on ejaculated dog, monkey, and human spermatozoa. Oral administration of the compound to adult male beagle dogs (50-246 mg/kg) or rhesus monkeys (85-100 mg/kg) was associated with a decline in motility of sperm in ejaculates obtained after dosing. In dogs the decline in sperm motility was correlated with the presence of ketoconazole in the seminal plasma, although the measured concentrations of ketoconazole were no more than one tenth that needed for in vitro activity. The serum levels of testosterone in the dogs receiving oral ketoconazole were profoundly suppressed but the extreme rapidity of onset of the ex vivo effect on sperm motility, which was noted within 4 hours of dosing, makes it unlikely that testosterone withdrawal plays more than a minor role in the spermatostasis. The results in animals invite further pursuit of this novel, rapid onset, reversible, single dose use of spermatostatic agents for their potential as male contraceptives.

Administration, Oral↗
PubMed1984

Intensive initial oral anticoagulation and shorter heparin treatment in deep vein thrombosis.

In order to investigate whether a more intensive initial oral anticoagulation still would be safe and effective, we performed a prospective randomized study in patients with deep vein thrombosis. They received either the conventional regimen of oral anticoagulation ("low-dose") and heparin or a more intense oral anticoagulation ("high-dose") with a shorter period of heparin treatment. In the first part of the study 129 patients were randomized. The "low-dose" group reached a stable therapeutic prothrombin complex (PT)-level after 4.3 and the "high-dose" group after 3.3 days. Heparin was discontinued after 6.0 and 5.0 days respectively. There was no difference in significant hemorrhage between the groups, and no clinical signs of progression of the thrombosis. In the second part of the study another 40 patients were randomized, followed with coagulation factor II, VII, IX and X and with repeated venograms. A stable therapeutic PT-level was achieved after 4.4 ("low-dose") and 3.7 ("high-dose") days, and heparin was discontinued after 5.4 and 4.4 days respectively. There were no clinical hemorrhages, the activity of the coagulation factors had dropped to the same level in both groups at the time when heparin was discontinued and no thromboembolic complications occurred. Our oral anticoagulation regimen with heparin treatment for an average of 4.4-5 days seems safe and reduces in-patient costs.

Administration, Oral↗
PubMed1984

Chemiluminescent immunosorbent assay of serum myoglobin based on the luminol reaction.

A simple and sensitive method for the determination of serum myoglobin is described. Myoglobin was determined in the range of 10-500 micrograms/1 by the chemiluminescent luminol reaction after adsorption to anti-myoglobin IgG onto a solid phase. Only 50 microliter of serum has to be used and the luminescent immunoassay (LIA) has a better sensitivity and a wider linear range than the conventional radioimmunoassay (RIA). However, in its present form LIA has a higher imprecision than RIA. In clinical specimens the correlation between the two methods was excellent.

Antibody Specificity↗
PubMed1984

Computed tomography of the brain in children with minor neurodevelopmental disorders.

Eighty-nine boys and twenty girls with minor neurodevelopmental disorders underwent cranial computed tomography (CT). Twenty-five per cent showed aberrations at CT. The incidence of manifest lefthandedness and of developmental language disorders was not higher among children with pathological CT findings than among those with normal ones. Nineteen per cent of the children with pathological CT results but only 1% of those with normal CT findings had had afebrile seizures. Abnormal chromatographic patterns of peptides and protein associated peptide complexes in the urine were found significantly more often in children with pathological than in those with normal CT.

Adolescent↗
PubMed1984

Screening for multiple endocrine neoplasia syndrome (type 1) in patients with primary hyperparathyroidism.

In 63 consecutive patients with primary hyperparathyroidism (HPT) a prospective screening study was undertaken for coexistent multiple endocrine neoplasma-(MEN)-syndrome type 1. The screening consisted of a clinical examination, a radiological examination of the sella turcica with skeletal tomography (and in equivocal cases computed tomography), visual field examination by perimetry and a hormonal evaluation including measurements of the serum levels of prolactin, gastrin, pancreatic polypeptide (PP) and subunits of human chorionic gonadotrophin (HCG-alpha and -beta). Clinical examination did not reveal any signs of endocrine disease suggestive of a MEN-1 syndrome. In only one case there was a radiological abnormality of the sella turcica; this patient had an empty sella syndrome and a raised serum prolactin value. All other prolactin values were within the normal range. In 41% of the patients raised serum gastrin levels were found; these tended to normalize after parathyroidectomy. As a group, patients with raised gastrin values were older than the others and generally they had hypo- or achlorhydria. The serum PP levels were raised in 28% of the patients but there was no clinical evidence of a pancreatic tumour in any of these cases, and the serum HCG-alpha and -beta levels were within the normal range in all patients but two. We conclude that the incidence of MEN-1 syndrome in unselected patients with primary HPT must be low, and that investigations for this syndrome are justified only in HPT patients with specific symptoms or with a positive family history.

Adult↗
PubMed1984

Increased luminol enhanced chemiluminescence from peripheral granulocytes in juvenile periodontitis.

The granulocyte function in patients with juvenile periodontitis (JP) (eight men and six women, aged 13-33 yr) and sex and age matched controls was determined by the luminol enhanced chemiluminescence (CL) induced by opsonized and unopsonized bacteria or latex beads. Maximal CL induced by latex beads with or without autologus serum did not differ between the two groups. However, bacteria with or without autologous serum seemed to induce a higher maximal CL in the JP group. The difference was statistically significant for the results obtained with opsonized bacteria. Serum opsonized bacteria induced a much higher maximal CL than the unopsonized. The opsonin dependent reaction indicates a close association with the process of phagocytosis. The increased CL of granulocytes in JP could indicate the formation of extracellularly free oxygen radicals with the potential to damage tissue. These observations support a possible involvement of the granulocytes in the pathogenesis of JP.

Adolescent↗
PubMed1984

Effects of substance P and somatostatin on taurocholate-stabilized and CCK- or secretin-induced choleresis in the anesthetized dog.

Eleven anesthetized dogs were provided with a common bile duct fistula, and the gallbladder was excluded. After stabilization of the bile flow by intravenous infusions of taurocholate, various peptides were administered intravenously. Substance P (SP) decreased the output of hepatic bile, bile acids, sodium, potassium, and bicarbonate by about 50%. When SP was superimposed on cholecystokinin (CCK)- or secretin-induced choleresis, all CCK-induced effects were abolished, whereas SP had a less pronounced anticholeretic effect when choleresis was induced by secretin. Somatostatin (SST) decreased the output of hepatic bile, bile acids, sodium, potassium, and bicarbonate by about 25%. SST had no inhibitory effect on CCK- or secretin-induced choleresis. It is suggested that the principal mode of action of SST on bile flow is indirect by inhibiting the release of choleretic hormones, whereas SP is suggested to act directly on the hepatocytes.

Animals↗