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Biomedical subjects

S Larsson

Publications and source records attributed to S Larsson.

At least 289 records · Page 16Linked to original sources
PubMed1984

Computed tomography in medial maxilla-orbital fractures.

The frontal process of the maxilla together with the anterior wall of the antrum constitute a major support of the midface. If this is fractured and goes unrecognized, serious facial deformities result. Fractures through this process occurred in 13 of 50 patients who received computed tomographic examination for facial trauma. The fracture had been missed on plain film examination in all but three of the 13 patients. The frontal process is usually displaced directly posteriorly in the more complex midface fractures. It may rotate about its long axis when associated with trimalar fractures and in some of the isolated injuries of the medial maxilla. Computed tomography is the ideal technique for demonstrating these fractures because of ease of examination, optimal anatomical display for demonstrating rotational and posterior displacements, and superior contrast in the severely traumatized facial skeleton.

Facial Injuries↗
PubMed1984

Attachment of Streptococcus pneumoniae to human pharyngeal epithelial cells in vitro--mechanism of binding.

To colonize mucosal surfaces and to invade underlying tissues, bacteria need to bind to components of the mucosa. Unattached bacteria are transported away from the surface with the fluid flow. By binding to the nasopharyngeal mucosa, Streptococcus pneumoniae causing otitis media may persist at the site of infection. High binding capacity of the bacterium and increased receptivity of the epithelial cells for attaching bacteria may both contribute to the susceptibility of patients prone to otitis. Thus, epithelial cells from children with frequent episodes of otitis bind attaching bacteria more readily than do cells from age-matched controls. The binding mechanism probably involves bacterial surface proteins and epithelial cell surface glycoconjugate receptors. Evidence is presented that phosphorylcholine, a component of the bacterial surface, as well as epithelial cell receptor analogues, that is, natural or synthetic saccharides analogous to the lactoneoseries of glycolipids, inhibits pneumococcal attachment. Inhibition of bacterial binding in vivo may be a new approach to prophylaxis against otitis media.

Adhesiveness↗
PubMed1984

Reconstruction of large anterior full-thickness defect in the chest wall after resection of chondrosarcoma.

Radical removal of a chondrosarcoma resulted in a very large full-thickness defect of the anterior chest wall, including the body of the sternum and adjacent parts of the ribs on both sides. The defect was closed with a double layer of Marlex mesh supported by metal bars bridging the gaps between the ends of resected ribs. This prosthesis was covered with bilateral latissimus dorsi muscle flaps and a split-thickness skin graft. The result, from both the functional and the cosmetic points of view, was excellent. The method permits closure of very large chest wall defects, enabling extensive radical removal of malignant tumours to prevent local recurrence.

Chondrosarcoma↗
PubMed1984

Advisability of concomitant immediate surgery for perforation and underlying disease of the esophagus.

Since 1979 our policy for management of esophageal perforation has included correction of underlying esophageal disorder as part of the initial treatment in selected cases. A series of 23 patients is presented, of whom 3 were managed conservatively and 20 surgically. The overall mortality rate was 8.7%. Concomitant operation of underlying esophageal disease and perforation was done in eight cases within 12 hours of the perforation. These operations included emergency resection and esophagogastrostomy in five patients (4 with stenosis and 1 with cancer). A Heller myotomy was done in addition to suture repair in two patients with achalasia, and a Belsey Mark IV hernia repair was added to the esophageal suture closure in a patient with gastroesophageal reflux and hiatal hernia. A postoperative fistula healed spontaneously in one of the eight patients, and the early postoperative course was uncomplicated in the other seven. Simultaneous correction of underlying esophageal disease in patients with iatrogenic perforation of the esophagus seems to be safe when perforation is diagnosed at an early stage. Such a radical approach is clearly beneficial.

Adult↗
PubMed1984

Malignant mesothelioma in two pairs of siblings: is there a hereditary predisposing factor?

Two pairs of siblings with malignant pleural mesothelioma are reported. One sister and brother experienced slight household asbestos exposure during childhood. Two identical-twin brothers were occupationally exposed to asbestos for only 8 years. The occurrence of this rare neoplasm in 2 pairs of siblings indicates that a hereditary predisposing factor may exist.

Aged↗
PubMed1983

A new design of double-barrelled microelectrodes for intracellular pH-measurement in vivo.

Intracellular pH (pHi) is one important regulator of cellular function. Most determinations of pHi in vivo have been performed by using indirect methods, e.g. CO2/HCO3 or DMO techniques, since no suitable direct method for reliable in vivo measurements have been available. In the present study a new type of double-barrelled microelectrode for simultaneous in vivo measurements of pHi and membrane potential (Em) is presented. The electrode was constructed on the basis of a combined recessed- and pencil-tip design. The tip diameter of the double-barrelled microelectrode was about 1.5 microns. The response of the pH channel was 55-60 mV/pH unit and the response time was between 30 s and 1 min. In vivo measurements of pHi and Em of rabbit skeletal muscle fibers are presented. A mean pHi of 7.00 (in 8 animals) at a membrane potential of -90.3 mV (arterial pH: 7.30, arterial PCO2: 6.39 kPa) was obtained. The new design of pH microelectrode offers some advantages over previously described microelectrodes and is well suited for in vivo measurements.

Animals↗
PubMed1983

Non-uniformity induced artifacts in single-photon emission computed tomography.

Changes of gamma camera uniformity due to choice of flood source configuration and camera head orientation, and influence of these changes on the reconstructed image, have been analysed using phantom measurements. The transfer of defects in the projection data to the reconstructed image has also been investigated using computer simulations. The results indicate that the use of gamma cameras for emission computed tomography will impose higher demands on gamma camera uniformity than conventional scintigraphy.

Models, Biological↗
PubMed1983

Oral acetylcysteine reduces exacerbation rate in chronic bronchitis: report of a trial organized by the Swedish Society for Pulmonary Diseases.

This multicentre trial was undertaken to confirm previous results indicating that long-term treatment with oral acetylcysteine reduces the exacerbation rate in patients with chronic bronchitis. Two hundred and eighty-five patients, smokers or ex-smokers, with chronic bronchitis started a pre-trial placebo-period of 1 month. After this run-in period 259 patients were included in the trial and randomized into two parallel groups. The patients were treated in a double-blind way either with acetylcysteine 200 mg b.i.d. or placebo b.i.d. for 6 months. The trial was completed by 98 patients in the acetylcysteine group and by 105 patients in the placebo group. Initially, there were no significant differences between the groups. Twice weekly, the patients filled in a diary card concerning symptoms. The number of exacerbations was assessed from these cards and at visits 2, 4 and 6 months after institution of therapy. The exacerbation rate was significantly lower in the acetylcysteine group in which 40% of the patients remained free from exacerbations compared to 19% in the placebo group. Sick-leave due to acute exacerbation was significantly less common in the acetylcysteine group. The drug was well tolerated.

Acetylcysteine↗
PubMed1982

Single photon tomographic imaging of a standard heart phantom with 201T1: a gamma camera based system.

A standard heart phantom (University of Iowa design), including discrete myocardial walls, a central blood pool, and a 24-cc transmural "cold" defect, was studied with both planar and transverse tomographic imaging. The heart phantom was filled with 201T1 and placed within a cylindrical tank containing water and 201T1 to simulate nonmyocardial background activity from the thorax. The tomographic imaging system used was a commercially available, rotating, large field-of-view gamma camera. Image reconstruction from 64 sampling angles was performed in a nuclear medicine minicomputer system. The percentage activity in the region of the defect (actual activity of 0) contrasted to the normal wall was compared between planar and 1.25-cm transaxial tomographic slices. Defect activity fell to between 65% and 85% of that of the opposing normal wall in planar images, whereas it fell to between 26% and 49% of that of the normal wall in the tomographic images. In most cases, tomographic defect activity was half or less than that in the planar image. The geographic extent of the defect was seen in an appropriate number of tomographic slices; i.e., the geographic 3.2-cm defect length was predominantly seen in three 1.25-cm transverse slices. We conclude that camera-based tomographic systems show promise for improved 201T1 myocardial defect detection and quantitation over conventional planar images.

Heart↗
PubMed1981

Differentiation of pyriform sinus cancer from supraglottic laryngeal cancer by computed tomography.

Nine pyriform sinus tumors and 16 supraglottic laryngeal lesions were studied by computed tomography. The pyriform sinus tumors had a much higher incidence of thyroid cartilage invasion (five of nine patients) and involved the posterolateral margins of the cartilage. Only two of 16 supraglottic tumors reached the thyroid cartilage, involving the midline or more inferior margins. The supraglottic tumors grew in a circumferential pattern, and when the pre-epiglottic space was involved, extension was bilateral. Lesions of the pyriform sinus more frequently showed unilateral involvement. Lymph node metastases were seen in an approximately equal proportion of patients in the two groups, and they correlated more with the size of the primary tumor than with its site of origin. Posteroinferior invasion of the space between the thyroid and cricoid cartilage was seen only with pyriform sinus lesions.

Carcinoma, Squamous Cell↗
PubMed1981

Differentiated treatment of intrathoracic oesophageal perforations.

A series of 44 consecutive patients with oesophageal perforation treated during the ten-year period 1969-1978 has been reviewed. Thirty perforations were caused by oesophagoscopy using a rigid instrument, often combined with dilation and/or biopsy, 4 were caused by a fibreoptic instrument and 10 were spontaneous ruptures. A benign stricture was the most commonly associated lesion in the oesophagus. Six patients with an iatrogenic perforation were treated conservatively without mortality. These patients were characterized by mild symptoms, early recognition, minor leakage from the oesophagus and no communication to the pleural cavity. Fourteen patients were treated with closed thoracic drainage. The overall mortality among these patients was 70%, but for those with a spontaneous rupture it was 100%. Twenty-four patients were treated surgically with a mortality of 20%. Individualized treatment is recommended.

Aged↗
PubMed1980

S100-glia regulation of GABA transport across the nerve cell membrane.

A technique has been devised to isolate and prepare fresh nerve cell plasma membranes in order to study the transport of biologically active substances across the membrane and in the two opposite directions. The membrane is placed tightly over a 30-micrometer diameter hole in a thin glass plate forming a partition between two compartments of a micro-chamber made from silicon rubber. The plasma membrane is usually placed with the outer surface facing the upper compartment. We have studied the transport of labeled GABA across the plasma membrane of Deiters' nerve cells and the effect of the brain-specific protein S-100 in its calcium form on this process. 100 nl samples were separated by thin layer chromatography and each sample analyzed by an instrument especially made for low level 3H- and 14C-measurements. The S-100, Ca2+ protein significantly increased the GABA transport across the nerve cell membrane by maximally 25% and against a gradient. The kinetics of the transport process, and inhibition by 2-4 diaminobutyric acid, furthermore supported the conclusion that the S-100, Ca2+-stimulated GABA transport was an active process. When a thin layer of the nerve cell's S-100-synthesizing glia was placed in contact with the plasma membrane - as in the vivo situation - the stimulation of GABA transport was abrogated. The S-100, Ca2+ protein, if absorbed on the nerve cell membrane, stimulates GABA transport across the membrane. This phenomenon seems to be regulated by the glia which cover all parts of the plasma membrane except the post-synaptic areas.

Animals↗