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Biomedical subjects

K Bergström

Publications and source records attributed to K Bergström.

At least 19 recordsLinked to original sources
PubMed1992

Reduction of fibrinogen adsorption on PEG-coated polystyrene surfaces.

Reduction of protein adsorption by coating surfaces with polyethylene glycol (PEG) is well documented. The present work has four goals related to these previous studies: first, to develop chemistry providing densely packed, covalently bound PEG on polystyrene (PS); second, to determine the ability of these modified surfaces to reject fibrinogen; third, to compare the protein-rejecting ability of branched and linear PEGs; and fourth, to examine the utility of an ELISA-type procedure for measuring protein adsorption. It was found that PEG-epoxide could be readily coupled to amine groups of poly(ethylene imine) (PEI), which had been preadsorbed onto an oxidized PS surface. The PEG groups on branched PEGs appear to act as an excluded volume to repel proteins, similar to arguments previously raised for linear PEGs. The results of protein adsorption studies showed that fibrinogen adsorption is significantly reduced by coating polystyrene with either linear or branched PEGs of 1500 to 20,000 in molecular weight. The ELISA technique was found to be equivalent in sensitivity to radiolabeled fibrinogen for estimating adsorption levels. It is expected that PEG-coated PS will have much utility in a variety of biomedical applications.

Adsorption↗
PubMed1992

Fibrin (ogen)-derived peptide B beta 30-43 is a sensitive marker of activated neutrophils during fibrinolytic-treated acute myocardial infarction in man.

Neutrophils, elastase, the specifically elastase-derived fibrin split product, B beta 30-43, and C-reactive protein were determined in 30 consecutive patients with acute myocardial infarction. At admission to the coronary care unit 4.2 +/- 0.8 hours after the onset of symptoms, all elements were increased above the reference levels, while compared with convalescent levels, only neutrophils and B beta 30-43 were increased. After the streptokinase treatment, neutrophils, elastase, and B beta 30-43 increased abruptly and peaked (p less than 0.0001) within 1.5 hours. Plasma creatine kinase MB and C-reactive protein reached their peak levels after about 12 and 24 hours, respectively. Peak indices of neutrophils and creatine kinase correlated (r = 0.60, p less than 0.0006). Compared with the age-matched reference range, the convalescent level of B beta 30-43 was increased (p less than 0.0001). Of the tested elements suggestive of neutrophil activation, B beta 30-43 showed signs of being the most sensitive. In keeping with animal studies, neutrophils are activated early during the course of acute myocardial infarction and their activation seems to become accelerated by fibrinolytic treatment. Neutrophils may remain activated in the convalescent phase.

Biomarkers↗
PubMed1992

Expression of Fc-gamma-RIII and fibronectin in peripheral polymorphonuclear neutrophils with increased response to Fc stimulation in patients with juvenile periodontitis.

The nature of increased luminol-enhanced chemiluminescence (CL) in peripheral polymorphonuclear neutrophils (PMN) in juvenile periodontitis is of pathophysiological interest and may serve as a model for tissue damage caused by granulocytes. Activation of PMNs by opsonized Staphylococcus aureus was compared with that of Actinobacillus actinomycetemcomitans and Bacteroides gingivalis, regarded as being more specific for juvenile periodontitis. The CL was higher in the PMNs from the patients, independently of bacteria and mode of opsonization (autologous serum or gamma-globulin). Fc-gamma-RIII assessed on the washed fragments from peripheral PMNs was significantly (p < or = 0.005) lower in the patients with juvenile periodontitis than in their pair-matched healthy controls, while the content of fibronectin was higher (p < or = 0.032). However, when Fc-gamma-RIII and fibronectin were studied in fresh PMNs by flow cytometry no difference could be found between the two groups. The increased generation of CL of peripheral PMNs found in patients with juvenile periodontitis seems to be independent of humoral factors and of bacterial species and may be related to the properties of the PMN cell membranes.

Adult↗
PubMed1992

Specificity of oligonucleotide probes complementary to evolutionarily variable regions of 16S rRNA from Mycoplasma hyopneumoniae and Mycoplasma hyorhinis.

Mycoplasma is the common name for the smallest free-living microorganisms, the Mollicutes. Mycoplasma hyopneumoniae is of great importance in veterinary medicine, causing enzootic pneumonia in pigs. M hyorhinis can cause polyserositis and may cause pneumonia in piglets. Oligonucleotides complementary to variable regions of 16S rRNA from these mycoplasmas were designed and used as probes for detection and identification of these mycoplasmas. The probe complementary to 16S rRNA of M hyorhinis gave a very weak cross-hybridisation with M hyosynoviae in filter hybridisation experiments, but not with any of the other porcine mycoplasmas tested. Three oligonucleotide probes complementary to M hyopneumoniae 16S rRNA were tested. One of the probes (Mhp6/30) was found to be specific to M hyopneumoniae, but the other two gave cross-hybridisation with M flocculare. Using the Mhp6/30 probe in direct filter hybridisation experiments, it proved possible to detect M hyopneumoniae in lung biopsies from experimentally infected pigs.

Animals↗
PubMed1992

Enhanced platelet function in acute myocardial infarction is attenuated by streptokinase treatment.

The aim of this study was to determine whether platelets are activated and aggregation is increased in myocardial infarction treated with streptokinase. Twelve consecutive patients were studied. Before streptokinase infusion (1.5 x 10(6) IU i.v. over a period of 1 h), 7 +/- 4 h after the onset of symptoms, fibrinogen, leucocyte and platelet functions were enhanced compared to reference values. Plasma fibrinogen was 3.1 +/- 0.6 g 1-1 (P less than 0.03), leucocyte count was 14.3 +/- 3.3 x 10(3) l-1 (P less than 0.0005), elastase was 39 +/- 8 micrograms l-1 (P less than 0.0002), beta-thromboglobulin was 68 +/- 71 micrograms 1-1 (P less than 0.0001) and filtragometer platelet aggregation time was 137 +/- 40 s (P less than 0.0001). After streptokinase the leucocyte count, elastase and beta-thromboglobulin levels increased further, by about 40% (P less than 0.02), 130% (P less than 0.02) and 140% (P less than 0.005), respectively. Fibrinogen was almost eliminated. Despite signs of increased activation, platelet aggregation was decreased as indicated by both filtragometer aggregation time, which increased by about 480% (P less than 0.003), and whole-blood aggregometry, in which electrical impedance decreased by about 65% (P less than 0.01).

Female↗
PubMed1992

Granulocyte elastase in gingival crevicular fluid. A possible discriminator between gingivitis and periodontitis.

The granulocyte elastase activity and the immuno-reactive (antigenic) granulocyte elastase of gingival crevicular fluid (GCF) were studied in 16 periodontitis patients and in 10 gingivitis patients. The elastase activity was measured with a low molecular weight substrate specific for granulocyte elastase. The antigenic elastase was determined with specific antibodies against granulocyte elastase. Intracrevicular sampling of GCF with paper strips for 30 s seemed to provide representative values of elastase. The elastase activity correlated with probing depth and attachment loss and appeared to be a measure of the degree of tissue destruction. Antigenic elastase represents the number of granulocytes in GCF and should thus be related to the degree of inflammation. The periodontitis patients and the gingivitis patients both had a similar degree of inflammation as measured by antigenic elastase per microliter GCF and gingival index. The elastase activity per microliter GCF, however, was higher in the periodontitis group. Elevated granulocyte elastase activity in GCF seems to be independent of inflammation and could thus be an indicator of patients at risk for periodontitis.

Adult↗
PubMed1992

Gd-DTPA-enhanced MR imaging of pituitary macroadenomas.

In a study comprising 40 patients with pituitary macroadenomas, MR imaging was performed before and after administration of Gd-DTPA. Before contrast administration T1- and T2-weighted images were obtained, and after the injection, frontal and/or sagittal T1-weighted images. Tumour extension and delineation, relationship to adjacent structures, and signal intensity patterns were evaluated. Compared with pre-contrast T1-weighted images only, post-contrast images provided considerable additional information, but not infrequently this information could also be extracted from pre-contrast T2-weighted images. Post-contrast images were superior regarding the tumour relationship to the cavernous sinus and to the normal pituitary tissue. T2-weighted images were helpful in the diagnosis of degenerative changes, in particular intratumoural haemorrhage. A positive correlation was found between the T2 value (from dual echo sequences) and the degree of enhancement in areas with an appearance of solid tumour tissue, and the enhancement was significantly lower in GH-secreting tumours than in non-secreting ones. It is concluded that the use of Gd-DTPA is often justified in pituitary macroadenomas, particularly in pre-operative evaluation.

Adenoma↗
PubMed1991

Isoamylase levels in bone marrow transplant patients are affected by total body irradiation and not by graft-versus-host disease.

The mean total serum amylase levels in patients was 3.2 +/- 0.5 mukat/l (+/-SE) before total body irradiation (TBI) prior to bone marrow transplantation of which 50% was due to pancreatic isoamylase and 50% salivary isoamylase. Total serum amylase increased to a maximum of 100.3 +/- 12.3 mukat/l on the first day after TBI and most of this increase was due to an increase in salivary isoamylase (90.0 +/- 12.1 mukat/l). In association with this, all patients had clinical symptoms of parotitis. An increase in pancreatic isoamylase was found in 27% of the patients; however, none of them had clinical symptoms of pancreatitis. Serum amylase levels returned to normal within 5 days after TBI but then decreased to subnormal values, remaining below the normal range for 3 weeks. Pancreatic isoamylase returned to pre-irradiation levels 1.5 months after TBI, while salivary isoamylase remained low for the rest of the observation time. TBI of 7.5 Gy at 26 cGy/min gave significantly lower salivary amylase at 2 days after TBI compared with 10 Gy at 4 cGy/min: 32 +/- 4 versus 76 +/- 13 mukat/l (P less than 0.05). At 2.5 and 6 months after TBI significantly higher total amylase levels were recorded for patients treated with 7.5 Gy of TBI compared with 10 Gy: 2.5 +/- 0.4 and 2.7 +/- 0.3 versus 2.0 +/- 0.5 and 0.8 +/- 0.3 mukat/l, respectively (P less than 0.01, P less than 0.05, respectively). Acute or chronic GVHD did not affect acinar cells in this investigation.

Adolescent↗
PubMed1991

Evaluation of customers' complaints about sunscreen cosmetics sold by the Swedish pharmaceutical company.

Sweden's pharmacies hold more than a 1/3 of the country's market for sunscreen cosmetics (sunscreens). Customers complaining of skin problems associated with the use of sunscreens obtained from the pharmacies were offered dermatological investigation and tests with standard allergens and sunscreens. 27 of 58 complaining customers were fully investigated, and another 8 partly tested. 2 disease entities, a burning sensation and erythema for one or a few days, and dermatitis with scaling lasting for up to 3 weeks, were about equally common. Contact or photocontact allergy to 2-hydroxy-4-methoxybenzophenone caused severe contact dermatitis in 3 individuals.

Benzophenones↗
PubMed1991

Acute peripheral facial palsy simulating Bell's palsy in a case of probable multiple sclerosis with a clinically correlated transient pontine lesion on magnetic resonance imaging.

A transient pontine lesion was demonstrated in a young adult male who had a complete acute peripheral facial nerve palsy due probably to multiple sclerosis. In the acute stage of the palsy. T2-weighted magnetic resonance imaging (MRI) revealed a high signal intensity in the ipsilateral pons in the region of the nucleus and pontine part of the facial nerve. The patient recovered completely 5 weeks after the onset of the palsy, and at this stage, the lesion in the brainstem was no longer demonstrable on MRI. The onset and course of the disease resembled the idiopathic form of facial palsy (Bell's palsy): the present findings along with recent MRI and topodiagnostic studies may indicate that in some cases of Bell's palsy the primary lesion is located centrally. By improved MRI techniques and intravenous contrast agents it may be possible to visualize and follow the disease process and ascertain more of the pathogenesis of Bell's palsy.

Acute Disease↗
PubMed1991

Deposition and gastrointestinal transit of conventional sucralfate tablets.

Sucralfate was labelled with 99mTc by the stannous reduction method. Tablets were compressed using 1 g of radioactive sucralfate and suitable additives. On the first test day, five fully informed healthy volunteers were given one radioactive tablet of sucralfate each, following 10 h fasting. On the second test day, the sucralfate tablet was given after a standard meal. The gastrointestinal transit of the 99mTc-labelled sucralfate was evaluated using gamma camera technique. The labelling of sucralfate with 99mTc by the stannous reduction method enables the deposition and the transition of sucralfate in the gastrointestinal tract to be monitored. The tablets disintegrated almost immediately after administration and the released sucralfate distributed homogenously over the entire stomach area, in both fasted and fed subjects. Transit from the stomach into the intestine was noted already 10 min after administration in fasted subjects, whereas the gastric emptying of sucralfate was markedly delayed in fed subjects. To achieve a wider and more homogenous distribution in the GI-tract, sucralfate tablets should be taken before eating.

Adult↗
PubMed1991

Comparison of MR imaging and CT in pituitary macroadenomas.

The findings on mid-field MR imaging and CT were compared retrospectively in 65 patients with pituitary macroadenomas. The evaluation comprised tumour extension and delineation, invasiveness, relationship to adjacent structures, and internal tumoral changes. MR was superior to CT except in the demonstration of bone changes and tumour calcification. The superiority of MR was most pronounced regarding cavernous sinus invasion, tumour relationship to the carotid arteries and optic chiasm, and tumour haemorrhage. Extensive bone changes were visualized with both methods; erosions were often seen only with CT. It is concluded that MR is the preferable method for evaluation of pituitary macroadenomas. CT is useful as a supplementary modality when detailed information on bone anatomy is required, particularly if a transsphenoidal surgical approach is contemplated.

Adenoma↗
PubMed1990

Analysis of caprine mycoplasmas and mycoplasma infections in goats using two-dimensional electrophoresis and immunoblotting.

Seven strains of mycoplasma have been characterized by two-dimensional polyacrylamide gel electrophoresis in combination with immunoblotting. The two-dimensional patterns of the strains were compared and similarities and differences are discussed. Hyperimmune rabbit antisera were used in the immunoblotting experiment to study the immunological cross-reactivity between the species. Sera from goats, naturally and experimentally infected with mycoplasma, were also used in the immunoblotting experiment to study the immune responses of the infected animals.

Animals↗
PubMed1990

Rebound of ICP after brain compression. An MRI study in dogs.

The rebound of intracranial pressure (ICP) occurring after decompression of an intracranial mass lesion was studied in an epidural balloon compression model. Intracranial morphology and brain tissue water content were assessed with magnetic resonance imaging (MRI). Fast and slow components of the transverse relaxation time (T2) were used as indicators of brain oedema development. During balloon compression a progressive prolongation of both the fast and the slow T2 components took place. Following deflation of the balloon both components increased rapidly, particularly the slow-T2. The MR scans displayed progressive occlusion of the aqueduct, and obliteration of the ambient and pontine cisterns. The changes in morphology and in water content after decompression had largely the same time course as the development of the rebound of ICP. In contrast, no changes in morphology and tissue water content occurred after hydrostatic brain compression achieved by subarachnoid fluid infusion. The findings suggest that the intracranial pressure rebound is caused by cerebral oedema accumulated during and particularly in the recirculation phase after an ischaemic injury of adequate intensity and adequate duration.

Animals↗
PubMed1990

Evaluation of syringomyelia and Chiari malformations using ultra-low magnetic resonance imaging.

The accuracy of ultra-low field magnetic resonance imaging (MRI) compared to medium-field MRI in detecting syringomyelia and associated Chiari malformations is examined. In all cases the size of the syrinxes and the type and extent of the Chiari malformations was clearly shown at low-field MRI. The present spatial solution and high sensitivity allows for low-field imagers to localize even minor morphological changes of the spinal cord, brainstem, and cerebellum.

Adolescent↗
PubMed1990

Delineation of gliomas with magnetic resonance imaging using Gd-DTPA in comparison with computed tomography and positron emission tomography.

Fourteen patients with cerebral gliomas were investigated by MR imaging using Gd-DTPA (Magnevist), CT with the contrast agent iohexol (Omnipaque) and, as a reference, positron emission tomography (PET) using 11C-L-methionine. Tumour areas with disruption of the blood-brain-barrier (BBB) as seen on MR and CT were compared with areas increased accumulation of methionine in PET. There were 6 patients with high-grade astrocytoma (grade III-IV), 5 with low-grade astrocytoma (grade I-II) and 3 with oligodendroglioma. In 4 high-grade tumours, PET showed a larger tumour or tumour tissue in additional areas, compared with enhancement on MR and CT, while in 2 cases the tumour extension was similar in the three modalities. In the low grade tumour group, the findings on PET differed from those on post-contrast MR or CT in 7 cases. In 3 of these cases, no disruption of the BBB was seen either on MR or on CT. In 2 of our 14 patients CT showed larger enhancement extension than MR and in 2 cases MR was superior to CT in this respect. The enhancement intensity was higher on MR in 4 patients and on CT in 2 patients. No definite difference in the delineation of tumour tissue between the T1 weighted SE sequences was found. The gradient echo sequences FLASH and FISP gave limited information that was less than that provided by the T1 weighted SE sequences. A greater increase in signal intensity in T1 weighted images was usually seen 5 min post-contrast in the high-grade tumours than in the low-grade ones.

Adult↗
PubMed1990

Magnetic resonance in Bell's palsy.

The brain and the brain stem were investigated by magnetic resonance (MR) in 19 patients with complete acute peripheral facial palsy, diagnosed as Bell's palsy. Five patients with a median age of 57 years had changes on T2 weighted MR: One patient showed transient signal changes with increased signal intensity in the ipsilateral brain stem. Another patient had persisting abnormal signals both in the brain and the brain stem. Two patients presented regions of high signal intensity in the subcortical cerebral white matter and still another patient had increased signal intensity in the periventricular white matter. MR abnormalities anatomically related to the facial nerve or its nucleus were not demonstrated. The significance of the MR findings is not quite certain but the MR pattern in conjunction with the patient's high median age most likely indicate vascular disease.

Adult↗