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Biomedical subjects

S Larsson

Publications and source records attributed to S Larsson.

At least 271 records · Page 15Linked to original sources

Clinical consequences of inadequate inhalation technique in asthma therapy.

The FEV1-increase after inhalation of a beta 2-stimulant metered-dose aerosol was studied in 23 patients treated by specialists. The effect of their spontaneous inhalation technique was compared with that of controlled inhalation, which was optimised by means of a device controlling the breathing pattern and release of the metered-dose aerosol. This allowed quantitative assessment of the loss of bronchodilatation caused by the spontaneous inhalation technique. Thirteen patients who were observed to make inhalation errors showed a significant loss of bronchodilatation (30%), whereas ten patients who were observed to make no inhalation errors showed an insignificant loss of bronchodilatation (13%). It is concluded that when a metered-dose aerosol is used in general clinical practice there is a considerable loss of potential efficacy.

Administration, Inhalation↗

Results of surgical treatment for iliofemoral venous thrombosis.

The long-term results after venous thrombectomy combined with a temporary arteriovenous fistula were evaluated in 19 patients. Clinical status, isotope phlebography, venous occlusion plethysmography and foot volumetry were performed after a mean follow-up time of 38 months (range 13-75). The primary operation was successful in 17 of the 19 patients; the 2 remaining had chronic occlusions of their iliac veins. At the time of closure of the arteriovenous fistula, i.e. 3 months after thrombectomy, 14 patients had a patent iliac vein. At follow-up eight patients were considered to have a patent iliac vein, eight had a partial restitution and three had an occluded iliac vein. The group as a whole had no impaired venous emptying of the leg, but the small group of patients with occlusion at follow-up according to isotope phlebography seemed to have an impaired venous emptying. Foot volumetry showed only minor signs of valvular insufficiency, mainly in limbs with distal extension of the initial thrombus or only partial restitution of venous patency. A good long-term result can be expected after venous thrombectomy with a temporary arteriovenous fistula particularly in younger patients where the thrombosis is limited to the iliofemoral segment. This emphasizes the importance of early operation before distal extension of the thrombus occurs.

Adolescent↗

Simplified endoscopic photography for anatomic correlation with CT and MR of the larynx and pharynx.

Improvements in photographic film and the availability of fluid light transmitters rather than fibro-optics permit endolaryngeal and nasopharyngeal photography to be conducted using the same light levels as simple diagnostic examinations of these areas. The added perspective of endoscopic examination can often clarify many confusing bulky lesions that distort CT and MR anatomy. Thus endoscopic photography is a tremendous teaching tool.

Adolescent↗

VA RNAs from avian and human adenoviruses: dramatic differences in length, sequence, and gene location.

Human adenoviruses encode low-molecular-weight RNAs, so-called VA RNAs, which are transcribed by RNA polymerase III. These RNAs are required for an efficient translation of viral mRNAs late after infection. The genes for the VA RNAs in the genome of CELO virus were mapped and characterized. The results showed a number of surprising differences between CELO virus and human adenovirus type 2 (Ad2). Thus, the CELO virus genome encoded only one VA RNA species, in contrast to human Ad2, which encoded two distinct species. The VA RNA from CELO virus was much shorter than the Ad2 VA RNAs (90 nucleotides compared with 160 nucleotides), and there existed no detectable primary sequence homology between them. The predicted secondary structure of CELO virus VA RNA was, however, similar to that of the Ad2 VA RNAs, implying that the folding rather than the primary sequence was the important feature for biological activity. CELO VA RNA also stimulated translation in a transient expression assay, as did the Ad2 counterparts, albeit with a much lower efficiency. The location of the gene for CELO VA RNA also differed from all previously characterized serotypes, suggesting that the genome organization of avian and human adenoviruses are different. Finally, termination of CELO VA RNA transcription occurred in a TTATT sequence which is unique as a stop signal for RNA polymerase III transcription.

Adenoviridae↗

Characterization of a low-molecular-weight virus-associated (VA) RNA encoded by simian adenovirus type 7 which functionally can substitute for adenovirus type 5 VA RNAI.

Human adenoviruses (Ads), like Ad type 2 (Ad2) and Ad5, encode a low-molecular-weight RNA (designated virus-associated [VA] RNAI) which is required for the efficient translation of viral mRNAs late after infection. We cloned and characterized a VA RNA gene from simian adenovirus type 7 (SA7) which appears to have biological activity analogous to that of Ad2 VA RNAI. Thus, SA7 VA RNA stimulates protein synthesis in a transient expression assay and can also functionally substitute for VA RNAI during lytic growth of human Ad5. The SA7 genome encodes only one VA RNA species, in contrast to human Ad2, which encodes two distinct species. This RNA is transcribed by RNA polymerase III in the rightward direction from a gene located at about coordinate 30 on the viral genome, like its Ad2 counterparts. SA7 VA RNA shows only a limited primary sequence homology with the Ad2 VA RNAs (approximately 55%); the flanking sequences, in fact, are better conserved than the VA RNA gene itself. The predicted secondary structure of SA7 VA RNA is, however, very similar to that of Ad2 VA RNAI, inferring that the double-stranded nature rather than the primary sequence of VA RNA is important for its biological activity.

Adenoviridae↗

Studies on final differentiation of rat renal proximal tubular cells in culture.

The ontogeny of effective Na and K permeability has been studied in renal epithelial cells isolated from the outermost superficial cortex from adult and young (10-15 days) rats. The cells were cultured for 2-4 days and exhibited phloridzin-inhibitable alpha-methylglucoside uptake, characteristic of renal proximal tubular cells (RPTC). Intracellular concentrations of K, Na, Cl, and P and kinetics of changes in intracellular ionic content after inhibition of Na-K-ATPase with 1 mM ouabain (or by incubation in low-K medium) were measured in individual cells using electron probe analysis. Intracellular concentrations of K, Na, Cl, and P were equivalent in young and adult rat RPTC. Adult rat and young rat cells preincubated in K-free medium rapidly recovered normal intracellular K and Na contents when returned to 5.5 mM K medium. The recovery was almost immediately blocked by ouabain. Effective permeabilities measured as half time of K efflux and Na influx after ouabain inhibition of Na-K-ATPase were higher in adult than in young RPTC cultured for less than 4 days. Effective K and Na permeabilities decreased significantly with increasing time in culture in adult but not in young rat RPTC. Among young rat RPTC, half times of Na and K fluxes were significantly correlated to age. Effective K and Na permeabilities were lower in both young and adult rat RPTC that had been serum deprived for 24 h than in cells that had been continuously cultured in serum. In cells cultured for 3 days and serum deprived for 1 day, the addition of serum significantly increased K and Na permeability both in young and adult RPTC, but the effect was more pronounced in young RPTC where permeability reached the same high values as in adult RPTC continuously cultured in serum. In conclusion, effective Na and K permeabilities and serum activation of "permeability units" change during ontogeny. These ontogenic changes might be blunted after a few days in culture due to dedifferentiation of adult rat RPTC.

Aging↗

Use of muscle flaps in the treatment of infected sternotomy.

Deep wound infection after open-heart surgery remains a major problem. In this paper potential indications and techniques for use of muscle flaps in the treatment of chronic sternal infections are discussed and the authors' early experience with such treatment is presented. A well vascularized muscle flap fills out the defect, may help to control infection, and accelerates healing. After adequate excision of infected tissue, bone and cartilage, the resulting defect is covered with a muscle flap immediately or after a period of open treatment. Coverage with a flap of pectoralis major muscle was used in five patients 3 weeks to 6 months after cardiac surgery. Primary healing occurred in two patients, secondary healing in one and healing with residual fistula in one patient. In the fifth case there was uneventful recovery with primary healing until death occurred from cerebral haemorrhage after 3 weeks. Use of muscle flaps seems to be a valuable complement in the management of severe sternotomy infections.

Aged↗

Regional cerebral blood flow determined with single photon emission computed tomography and positron emission tomography. A comparative study.

The regional uptake of 99Tcm-labelled HMPAO has been measured with single photon emission computed tomography (SPECT). The potential value of 99Tcm-HMPAO as a flow tracer was evaluated. The uptake of 99Tcm-HMPAO as a function of time indicated that the tracer was trapped in the brain. The uptake images were compared with results from quantitative regional cerebral blood flow (rCBF) measurements using positron emission tomography (PET) and with 11C-fluoromethane used as a tracer. There was a strong correlation between the uptake of 99Tcm-HMPAO and rCBF. The conclusion was that the uptake of 99Tcm-HMPAO was dependent on rCBF.

Cerebrovascular Circulation↗

Constant rate of infusion--improvement of tests for teratogenicity and embryotoxicity.

Sodium salicylate was used as a model substance to investigate whether the embryotoxic effects on rat fetuses varies between two modes of administration. A marked increase in fetal adverse effects was observed at analgetic doses with the once-a-day bolus regimen compared to the constant rate input. The difference was less marked at antirheumatic levels.

Abnormalities, Drug-Induced↗

Ectomography--a tomographic method for gamma camera imaging.

In computerised gamma camera imaging the projections are readily obtained in digital form, and the number of picture elements may be relatively few. This condition makes emission techniques suitable for ectomography--a tomographic technique for directly visualising arbitrary sections of the human body. The camera rotates around the patient to acquire different projections in a way similar to SPECT. This method differs from SPECT, however, in that the camera is placed at an angle to the rotational axis, and receives two-dimensional, rather than one-dimensional, projections. Images of body sections are reconstructed by digital filtration and combination of the acquired projections. The main advantages of ectomography--a high and uniform resolution, a low and uniform attenuation and a high signal-to-noise ratio--are obtained when imaging sections close and parallel to a body surface. The filtration eliminates signals representing details outside the section and gives the section a certain thickness. Ectomographic transverse images of a line source and of a human brain have been reconstructed. Details within the sections are correctly visualised and details outside are effectively eliminated. For comparison, the same sections have been imaged with SPECT.

Brain↗

Antimicrobial susceptibilities of Listeria monocytogenes strains isolated from 1958 to 1982 in Sweden.

Antibiotic susceptibility was studied in 175 clinical isolates of Listeria monocytogenes. There were no major changes in the susceptibility of strains between 1958 and 1982. Benzylpenicillin and ampicillin had MICs for 90% of the strains (MIC90) of 0.5 micrograms/ml. Gentamicin also had good activity against L. monocytogenes, with an MIC90 of 1.0 microgram/ml. All the new beta-lactamase-stable cephalosporins tested had relatively poor activity against L. monocytogenes. Of the bacteriostatic antibiotics, trimethoprim had by far the lowest MIC90 (0.06 microgram/ml), and in combination with sulfamethoxazole (co-trimoxazole), it had an MIC90 of 0.5 microgram/ml. Both erythromycin and doxycycline had low MIC90s (0.25 microgram/ml).

Anti-Bacterial Agents↗

CT-directed fine needle aspiration biopsies of masses in the head and neck.

Fine needle aspiration (FNA) biopsy is a safe, reliable, and cost-effective technique available for the evaluation of head and neck masses. Its utility is enhanced by the use of CT-directed aspiration. Candidates for CT-directed FNA include patients with: 1. deep-seated lesions; 2. distorted anatomy as a result of surgery or irradiation; 3. medical problems which contraindicate general anesthesia. The initial UCLA experience with this modality is reviewed. In certain clinical settings, CT-directed FNA can be a highly productive source of clinical information.

Adenocarcinoma↗

Surgical removal of pulmonary metastases from renal cell carcinoma.

Thirty-three patients operated on for pulmonary metastases from renal cancer were followed up for a minimum of 5 years or to death. The 5-year survival was 21%. There was a tendency to better survival in patients operated by lobectomy rather than limited resection. Extended operations carried a grave prognosis. Manifest metastatic disease within one year after the primary operation showed shortened survival. Repeated operations were possible, with good results. It is concluded that operations for pulmonary metastases can be performed with good results. However, the effect is a palliative one as the ultimate cause of death in all instances was the spread of the cancer disease.

Carcinoma, Renal Cell↗

Immunological abnormalities in shrinking pleuritis with atelectasis.

The immunological status of 14 patients with shrinking pleuritis with atelectasis (SPA) was assessed by skin testing for delayed hypersensitivity reactions and in vitro tests of peripheral blood lymphocyte reactivity. The results were compared with those of 3 control groups, one consisting of healthy men, one of workers exposed to asbestos and one of workers exposed to quartz dust. Only 2 of 14 SPA patients showed a positive skin reaction to 2.4-dinitrochlorobenzene (DNCB). The cutaneous reactions to candida and varidase were significantly increased in the SPA group compared with the other groups (p less than 0.05). The response of the blood lymphocytes to stimulation with phytohaemagglutinin was significantly decreased in the SPA group (p less than 0.01), as was unstimulated lymphocyte proliferation (p less than 0.05). The results suggest a primary or secondary immune abnormality in the SPA group. The exact nature of the defect requires further elucidation.

Adult↗