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S Persson

Publications and source records attributed to S Persson.

At least 73 records · Page 4Linked to original sources
PubMed1991

Expression of different cytokeratin subclasses in human chordoma.

A detailed immunohistochemical characterization of different cytokeratin subclasses was performed on frozen tumour tissue from three classical chordomas. Simple epithelium cytokeratins Nos 8, 18, and 19 were detected in all tumour cells while cytokeratin No. 7 was not found. Cytokeratins characteristic of squamous differentiation, including keratinization, were generally lacking, with the exception of the varying expression of cytokeratin No. 4. Vimentin was found in all the tumours, while they lacked desmin immunoreactivity. The present study indicates the co-expression of vimentin and cytokeratins, predominantly of the simple epithelium type. In addition, chordoma cells have the ability to express cytokeratins characteristic of squamous differentiation. This finding corresponds well to the electron microscopic findings of tonofilament bundles ending in well-developed desmosomes.

Antibodies, Monoclonal↗
PubMed1991

Multivariate study of enterobacteria and Pseudomonas in saliva of patients with acute leukemia.

The effect of antibacterial treatment on the prevalence of gram-negative rods (enterobacteria and Pseudomonas) in the mouths of patients with leukemia was studied. Of the patients' salivary samples, 45% contained gram-negative rods compared with 12% in a control group of healthy persons. The antibacterial resistance patterns of gram-negative rods from healthy persons were different from those of the hospitalized patients. No relationship was found between the amount of antibacterial treatment and presence of gram-negative rods. The gram-negative rods recovered from individual patients were usually not resistant to the antibacterial agents given to the patients in question. Only a few patients harbored the same clone of a gram-negative rod for a lengthy period. The resistance patterns of these clones of gram-negative rods were similar to those of gram-negative rods that were transient in the mouth. It was concluded that resistance to antibacterial agents is not a factor of major importance for the capacity of the gram-negative rods to become established in the mouths of hospitalized patients with leukemia.

Adolescent↗
PubMed1991

Classical and chondroid chordoma. A light-microscopic, histochemical, ultrastructural and immunohistochemical analysis of the various cell types.

The aim of the present investigation was to characterize the various cell types of classical and chondroid chordomas. Eight cases of classical chordoma, 1 case of sacrococcygeal chordoma with chondroid areas and 2 cases of spheno-occipital chondroid chordoma were studied. Ultrastructurally and immunohistochemically (immunoreactivity for cytokeratins, epithelial membrane antigen [EMA], tissue polypeptide antigen [TPA] and human milk fat globule protein [HMFG]) the 3 cell types (physaliferous, epithelial-like, and spindle-shaped) recognized light-microscopically presented features of epithelial differentiation and rather formed a continuous spectrum than being distinct cell types. The chondroid areas of the chondroid chordomas had similar ultrastructural and immunohistochemical properties except for the lack of immunoreactivity for EMA and HMFG. The results of the critical electrolyte concentration technique according to Scott and Dorling indicated that there was no difference in the sulfated glycosaminoglycan content between classical and chondroid chordomas: all the tumors contained chondroitin sulfate. The presence of chondroitin sulfate, immunoreactivity for vimentin and S-100 protein and areas of cartilaginous differentiation in three cases indicate a relationship both to chondromatous tumors and to normal notochord, from which chordoma is believed to originate.

Adult↗
PubMed1991

Clenbuterol plasma concentrations after repeated oral administration and its effects on cardio-respiratory and blood lactate responses to exercise in healthy Standardbred horses.

To evaluate the effects of clenbuterol on cardio-respiratory parameters and blood lactate relation to exercise tolerance, experimental horses performed standardized exercise tests on a high-speed treadmill before and after administration of the drug. Clenbuterol was administered in feed to six healthy Standardbreds at a dose rate of 0.8 micrograms/kg b.wt twice daily for 5.5 days. Each horse was tested twice, without and with a respiratory mask, during two consecutive days. One week elapsed between the baseline tests without drug and the tests with clenbuterol treatment (each horse served as its own control). The results show an unchanged heart rate response to exercise 2 h after the last clenbuterol administration. The blood lactate response and the arterial oxygen tension during exercise did not differ before and after drug treatment. The oxygen uptake as well as pulmonary ventilation relative to the work load performed was essentially unaffected. The arterial pH during exercise was significantly increased (P less than 0.05) following clenbuterol treatment. Plasma levels of clenbuterol were maximal 2 h post-administration with values between 0.45 and 0.75 ng/ml. The plasma half-life of elimination was 10.4 h (+/- 2.25 SD). In conclusion, clenbuterol did not cause any major effects on the cardio-respiratory and blood lactate parameters studied in healthy horses performing submaximal exercise tolerance tests.

Administration, Oral↗
PubMed1991

Proximal attachment loss in Swedish adolescents.

The present study describes periodontal conditions in 22 adolescents with proximal attachment loss greater than or equal to 2 mm (AL) and 22 matched referents without AL, all identified in a cross-sectional study of 570 16- and 18-year-old. The cases were followed for 3 years and the referents for 1 year while they were in the care of an organized dental health system. With the exception of 1 case with Morbus Hodgkin, the case and referent groups had a similar background with respect to general health and participation in the dental health program. Bleeding on probing was found at AL sites in 12 of the cases and at corresponding sites in 4 referents. 2 cases had a history of eruption disorders at the AL sites, 1 case had experienced a defective filling and 1 had a root fissure at the AL sites. At re-examinations after 1 and 3 years, 10 out of 21 earlier identified AL cases did not meet the criterion of 1 or more sites with AL greater than or equal to 2 mm. None of the cases showed progression greater than or equal to 2 mm of the lesions. In 1 case, the number of AL sites increased during the period. 4 of the cases harboured Actinobacillus actinomycetemcomitans (A.a.) at AL sites in year 1 and 3 in year 3. 8 of the cases and 4 referents had antibodies specific for A.a.-leukotoxin. The 2 most severe cases, in terms of number of sites with AL, showed bleeding at 1 or more of the AL sites, harboured A.a. at these sites and had serum titers against A.a.-leukotoxin.

Adolescent↗
PubMed1991

Presence of Streptococcus mutans and lactobacilli in saliva and on enamel, glass ionomer cement, and composite resin surfaces.

The quantity of S. mutans, total streptococci, and lactobacilli on sound enamel surfaces and 1-yr-old glass ionomer cement and composite resin fillings with the cervical margins placed subgingivally was compared intra-individually. The amount of bacteria was compared to their number in saliva. The evaluation was done in a cross sectional study, where the patients continued to use their customary oral hygiene procedures and during a 14-day period of experimental plaque formation. The number of lactobacilli and S. mutans recovered from the test surfaces indicated that the critical salivary concentrations necessary for the isolation of S. mutans and lactobacilli from glass ionomer cement and composite resin surfaces are the same as for the enamel surfaces. The fluoride levels in plaque adjacent to glass ionomer cement will not become high enough to inhibit the accumulation of the investigated bacteria.

Colony Count, Microbial↗
PubMed1991

Studies on blood rheology in patients with primary pulmonary hypertension.

The rheologic properties of blood were studied in 6 patients with primary pulmonary hypertension (PPH) and compared with those of a control group of 10 healthy subjects. Blood viscosity was studied with a rotational viscometer and blood cell deformability with a filtrometer giving values for clogging particles (CP) and red cell transit time (RCTT). Blood viscosity at varying shear rates was found to be increased both at natural (p less than 0.025-0.005) and standardized hematocrit, 45% (p less than 0.05 at 40 s-1) in patients with PPH. Red cell deformability was reduced as indicated by a significant increase of RCTT (p less than 0.01). Increased values for hematocrit (p less than 0.001), hemoglobin concentration (p less than 0.001), and erythrocyte count (p less than 0.005) were found and decreased values for mean corpuscular hemoglobin concentration (MCHC) (p less than 0.025) and HDL cholesterol (p less than 0.005). Plasma viscosity, white cell deformability, white cell count, mean corpuscular volume (MCV), and plasma fibrinogen concentration did not significantly differ from the values found in the control group. It is concluded that patients with PPH have impaired blood rheology. The hemorheologic abnormalities in these patients may be of hemodynamic significance.

Adult↗
PubMed1991

Calcium antagonists in secondary prevention after myocardial infarction.

A reliable theoretical background exists to support a secondary preventive effect of calcium antagonists after myocardial infarction. Recent studies also indicate that positive results can be achieved with diltiazem and, in particular, verapamil, provided that they are not given to patients suffering clinically manifest myocardial failure during the acute phase of the disease. When the results of treatment with verapamil and diltiazem are compared with comparable studies with beta-blockers, there is no convincing difference as to their effect on a reduction in mortality. However, studies on nifedipine have shown a negative trend, indicating that the calcium channel blockers should not be regarded as one entity in this respect.

Calcium Channel Blockers↗
PubMed1990

Variability of measurements of cranial growth in the rabbit.

This study concerns techniques used in experimental cranial growth research: roentgen cephalometry, roentgen stereophotogrammetry, and gross measurements (osteometry). A comparison of the precision of these methods has not been found in the literature. Computation of technical errors is fundamental to the sound evaluation of registered findings, and such a presentation must be obligatory in all biometric reports. We compared the measurement error of roentgen cephalometric and osteometric data with that obtained by roentgen stereophotogrammetry (RSA). RSA demonstrates a superior replicability, and this technique gives possibilities for kinematic and volumetric determinations simultaneously with distance evaluation. Roentgen cephalometry has the advantage of enabling distance and angular measurements between any well-defined skeletal points or lines. This technique, preferably after implantation of bone markers, is a reliable alternative, but optimal results necessitates calculations of the magnification factor for each bone segment involved. Direct osteometry does not contribute additional information, but problems of image magnification are omitted. Preferably, one individual should perform all measurements regardless of the method used. Growth rates and values calculated by one technique cannot be directly transformed to some other approach. In all probability, assessments of distance changes would gain substantially by using one technical approach consistently throughout actual age intervals. The least variable measurements of sutural growth are made for sutures growing primarily in one plane and with substantial growth rates. One must realize that differences among studies may be due to the limitations of, in particular, the cephalometric and osteometric techniques.

Animals↗
PubMed1990

Production of volatile sulfur compounds by various Fusobacterium species.

In 12 species of Fusobacterium the following characteristics were studied; the desulfhydration of L-cysteine and L-methionine by resting cell suspensions, the formation of alpha-keto-acids from L-cysteine, D-cysteine and L-methionine by cell extracts, and the formation of hydrogen sulfide from L-cysteine, D-cysteine and L-cysteine by cell extracts separated by polyacrylamide gel electrophoresis. Multiple forms of L-cysteine desulfhydrase activity were found in most of the species. In some of them also D-cysteine desulfhydrase activity was demonstrated. Seven of the species had high L-methionine gamma-lyase activity. L-cysteine activity was present in 5 of the species.

Carbon-Sulfur Lyases↗
PubMed1990

The formation of hydrogen sulfide and methyl mercaptan by oral bacteria.

The capacity to form volatile sulfur compounds was tested in bacteria isolated from subgingival microbiotas and in a representative number of reference strains. A majority of the 75 tested oral bacterial species and 7 unnamed bacterial taxa formed significant amounts of hydrogen sulfide from L-cysteine. The most active bacteria were found in the genera Peptostreptococcus, Eubacterium, Selenomonas, Centipeda, Bacteroides and Fusobacterium. Methyl mercaptan from L-methionine was formed by some members of the genera Fusobacterium, Bacteroides, Porphyromonas and Eubacterium. When incubated in serum for 7 d, the most potent producers of hydrogen sulfide were Treponema denticola and the black-pigmented species, Bacteroides intermedius, Bacteroides loescheii, Porphyromonas endodontalis and Porphyromonas gingivalis. P. endodontalis and P. gingivalis also produced significant amounts of methyl mercaptan in serum. No other volatile sulfur compound was detected in serum or in the presence of L-cysteine and L-methionine. These findings significantly increase the list of oral bacteria known to produce volatile sulfur compounds.

Bacteroides↗
PubMed1989

Increased neuropeptide-converting enzyme activities in cerebrospinal fluid of opiate-tolerant rats.

Rats were given a continuous subcutaneous infusion at constant rate with either morphine, the opioid agonist/antagonist analgesic dezocine or saline. Tolerance to the antinociceptive effect of morphine or dezocine was complete on day 8, when cisterna magnum cerebrospinal fluid (CSF) was sampled under anesthesia. The activity of the enzymes cleaving dynorphin A (DCE) and substance P (SPE) was measured in the CSF. It was found that the animals treated with morphine had a 2- to 3-fold increase in both DCE and SPE activities. The animals treated with dezocine showed a similar increase in the activity of DCE, whereas SPE did not significantly change. These enzymes may therefore play a role in the development of tolerance to opioid analgesic drugs. The experiments show that chronic opioid treatment affects peptidergic mechanisms.

Animals↗
PubMed1989

Pharmacokinetics and cardio-respiratory effects of oral theophylline in exercised horses.

The pharmacokinetics of theophylline at rest and the effects on cardio-respiratory and blood lactate responses to exercise were investigated after repeated oral administrations in six healthy Standardbred horses. A dose of 5 mg/kg body weight was administered every 12 h. The binding of theophylline to plasma protein was also determined. There was good agreement between predicted and observed plasma concentrations of theophylline at steady state. The mean half-life of elimination was shown to be 17.0 +/- 2.5 h, the mean half life of absorption was 1.6 +/- 1.8 h, the apparent volume of distribution was 852 +/- 99.0 ml/kg and total plasma clearance 0.61 +/- 0.08 ml/kg/min. Theophylline showed very low plasma protein binding (12%). The heart rate and blood lactate levels, during and after exercise, were significantly increased during theophylline-treatment. There was an increase of the arterial oxygen tension after exercise and the arterial carbon dioxide values before and after exercise were significantly lower than the premedication values. No severe adverse effects of the drug were noted. The recommended oral dose is therefore 5 mg/kg every 12 h but due to inter-individual variation, an adjustment of the dose may be necessary. The changes in the studied exercise parameters indicate that the performance capacity may be impaired by theophylline in the healthy horse.

Administration, Oral↗