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Biomedical subjects

A Larsson

Publications and source records attributed to A Larsson.

At least 289 records · Page 16Linked to original sources
PubMed1992

Glycerol production in subcutaneous adipose tissue in lean and obese humans.

To estimate the regional subcutaneous glycerol production rate in normal and obese humans, the venous arterialized plasma glycerol, interstitial glycerol in the subcutaneous adipose tissue together with adipose tissue blood flow (ATBF, ml/100 g.min) were measured in the postabsorptive state and for 2 h after ingestion of 100 g of oral glucose. Eight lean and eight obese men with normal oral glucose tolerance tests were investigated with the subcutaneous microdialysis technique and 133Xe clearance. In the postabsorptive state, the interstitial glycerol concentrations in lean and obese subjects were 170 +/- 21 vs. 282 +/- 28 microM (P less than 0.01) and 156 +/- 23 vs. 225 +/- 12 microM (P less than 0.05) in the abdominal and femoral subcutaneous adipose tissue, respectively. The corresponding arterial glycerol levels were 54 +/- 4 vs. 75 +/- 14 microM (NS). Abdominal ATBF was greater in lean subjects (3.2 +/- 0.6 vs. 1.6 +/- 0.3; P less than 0.05), whereas femoral ATBF was similar in both groups (2.7 +/- 0.4 vs. 2.4 +/- 0.7). Estimated mean local glycerol release (mumol/100 g.min) was similar in the lean and obese group (0.16 +/- 0.03 vs. 0.20 +/- 0.05 and 0.18 +/- 0.02 vs. 0.17 +/- 0.04) in the abdominal and femoral site, respectively. We conclude that glycerol production from the subcutaneous tissue is increased in obesity, irrespective of adipose tissue distribution. This enhancement is due to the increased adipose tissue mass.

Adipose Tissue↗
PubMed1992

Natural surfactant instilled in premature lambs increases lung volume and improves ventilation homogeneity within five minutes.

The immediate effects on lung volume, ventilation homogeneity, and lung mechanics of tracheal instillation of surfactant were studied in premature lambs, gestational age 120-122 d, with respiratory distress syndrome. Six lambs received surfactant by tracheal instillation 25 min after delivery by cesarean section; five received only vehicle and served as controls. The lambs were studied for 60 min thereafter. Functional residual capacity was measured with a computerized tracer gas washin-washout technique using sulfur hexafluoride as tracer gas. A measure of ventilation inhomogeneity (pulmonary clearance delay) was also calculated from the washout curves. Pressure-volume curves were studied with an interrupter technique during deflation of the lungs from an airway pressure of 30 cm H2O. In the surfactant group, arterial oxygenation and ventilation homogeneity improved within 5 min of giving surfactant; major increases in functional residual capacity, vital capacity, and compliance occurred within 5 to 20 min and were followed by gradual further improvements. The pressure-volume curve thus increased in amplitude and became steeper, but the lung volumes at various inflation pressures, and compliance, remained constant when expressed as fractions of total lung capacity volume. It is concluded that an improvement in lung volume, respiratory mechanics, and ventilation homogeneity occurs very soon after surfactant instillation and that there is a phase of successive further improvement over the next hour. Although the amplitude of the pressure-volume curve varied considerably, its basic shape varied little. This suggests that opening of new distal airways by surfactant predominated over changes in the mechanics of already aerated lung regions.

Animals↗
PubMed1992

Primary Sjögren's syndrome in patients with multiple sclerosis.

The relationship between multiple sclerosis (MS) and primary Sjögren's syndrome (PSS) is ambiguous; it was suggested that some patients diagnosed with MS may instead have PSS. In a recent epidemiologic study, the prevalence of PSS was 2.7% in southern Sweden. We randomly selected 30 patients with definite MS from our patient population and investigated them for evidence of PSS according to the Copenhagen criteria. One patient had clinical symptoms compatible with PSS and also fulfilled the Copenhagen criteria. In addition, five patients had keratoconjunctivitis sicca, one had xerostomia, and three had histopathologic evidence of sialadenitis in the lower lip salivary glands. However, one of these findings alone is not sufficient to support the diagnosis of PSS. We conclude that MS and PSS may coexist in the same individual, but PSS is not more common among MS patients than expected in the general population.

Antibodies, Antinuclear↗
PubMed1992

Viability, prostaglandin E2 production, and protein handling in normal and inflamed human colonic mucosa cultured for up to 48 h in vitro.

Human colonic mucosa obtained from colon cancer resections ('normal') and from colectomies owing to ulcerative colitis (inflamed) were cultured for up to 48 h in vitro. The 3H-leucine incorporation in normal tissue decreased to 52% (p less than 0.001) at 48 h compared with 24 h. The protein synthesis in normal but not in inflamed explants was significantly (p less than 0.01) improved at 48 h, reaching 72% of the 24-h value, on additions of insulin and the protease inhibitors aprotinin, soyabean trypsin inhibitor, and N alpha-tosyl-L-lysine chloromethyl ketone to the culture medium. Inflamed tissue had significant protein losses of 15% after 24 h and 29% after 48 h in culture, and the excretion of precipitable 3H-leucine-labelled proteins could be as high as 20%/24 h. A slight protein loss was observed in normal tissue after 48 h in culture, but the excretion of labelled proteins was very low (3%). The prostaglandin E2 (PGE2) production in both normal and inflamed tissue displayed an increasing non-linear pattern with time in culture, with higher values for inflamed tissue. The PGE2 release profiles and the differences in basic protein metabolism between normal and inflamed human colonic biopsy specimens in culture might reflect important characteristics of the inflammatory process.

Animals↗
PubMed1992

Oral mucosal findings associated with chewing tobacco in Sweden--a clinical and histological study.

Twenty men of mean age 51,9 years who used Swedish chewing tobacco as their only tobacco habit were examined for clinical and histological changes. On average they had been chewing tobacco for 10,7 hours daily for 11,3 years. The most common clinical finding was a leukoedema-like change of the buccal mucosa at the site where the quid was held after chewing. Ten subjects showed changes similar to mild snuff-induced ones. Histological findings corresponded well with the clinical ones. It appears that oral mucosal changes associated with chewing tobacco in Sweden are discrete.

Adult↗
PubMed1991

The effect of pancreatic procolipase and colipase on pancreatic lipase activation.

Intestinal fat digestion is carried out by the concerted action of pancreatic lipase and its protein cofactor colipase. Colipase is secreted from pancreas as a procolipase and is transformed into colipase by the trypsin cleavage of the Arg5-Gly6 bond during liberation of an N-terminal pentapeptide. The kinetic parameters for the lipase-colipase system compared to the lipase-procolipase system has been compared using trioctanoin and Intralipid as substrates. It was found that at pH 7.0 the Kmapp using Intralipid as substrate was the same for procolipase and colipase, 0.06 mM and 0.05 mM, respectively. At pH 8.0, however, the Kmapp were different-0.23 mM for procolipase and 0.08 mM for colipase. In a similar way the binding between colipase and lipase had a dissociation constant of 2.4 x 10(-6) M at pH 7.0, while for procolipase--lipase binding the dissociation constant was 4.1 x 10(-6) M with no significant difference. At pH 8.0 the binding between colipase and lipase was stronger, Kd being 2.0 x 10(-7) M, while weaker for procolipase and lipase, Kd being 1.0 x 10(-5) M. It is concluded that at the physiological pH value as is found in the intestine, the activation of procolipase to colipase has no influence on the hydrolysis of trioctanoin or Intralipid in the presence of bile salt.

Animals↗
PubMed1991

Calculation of affinity constants directly from homologous displacement curves.

Homologous displacement experiments are described in which the binding of labelled ligand (tracer) was inhibited with the same ligand unlabelled (inhibitor). Data were evaluated with a direct curve-fitting method. The equation used employs the concentration of unlabelled ligand as the independent variable and the fraction of tracer bound (p) as the dependent variable. The other entities of the equation are the dissociation constant (Kd), the maximal fraction of tracer bound (Po) and the tracer concentration (T). Different options exist regarding the insertion of Po and T as parameters or constants in the curve-fitting. When applied to experimental data obtained from the binding of dinitrophenyl-hapten by a monoclonal antibody, the least interexperimental variation in affinity was obtained when both Kd and Po were estimated as parameters, and T was inserted as a constant. This calculation procedure achieves more reproducible results than those obtained with the Scatchard plot and the Langmuir curve, even after exclusion of the most scattered data points.

Antibodies, Monoclonal↗
PubMed1991

Immunoglobulins and monoclonal anti-blastocyst antibodies in the mouse uterine secretion during the early pre-implantation period.

A Sepharose bead blot technique was used to study immunoglobulins in the uterine secretion of mice during the pre-implantation stage. Secretion collected by Sepharose beads contained IgA, IgG, and IgM. The method could be made ten-fold more sensitive by using anti-mouse IgG or IgM conjugated to Sepharose beads. It has also been demonstrated that when injected intravenously, biotinylated purified immunoglobulins, both non-specific mouse myeloma IgG and IgM and specific anti-blastocyst IgG and IgM, is able to pass into the uterine cavity of the mouse. It was further shown that when injected systemically, anti-blastocyst antibodies can reach the blastocyst. Functionally active specific antibodies against morulae and/or blastocysts may, therefore, be able to influence the pre- and peri-implantation development of the embryo and could serve as a useful model for experiments directed towards the identification of immunological contraceptive procedures.

Animals↗
PubMed1991

Failure to detect MHC class II associations of the human immune response induced by repeated malaria infections to the Plasmodium falciparum antigen Pf155/RESA.

Available evidence suggests that human T and B cell responses to a major Plasmodium falciparum malaria antigen (Pf155/RESA) in individuals primed by repeated infections are genetically regulated. In the present study we have attempted to establish whether these regulations reflect genetic restrictions imposed on the immune response by class II molecules of the donor's MHC system. T cell activation (proliferation and IFN-gamma release in vitro) and antibody activity (ELISA) were assayed with synthetic peptides corresponding to major Pf155/RESA epitopes. To associate T cell and antibody responses with the donors' MHC class II genotypes, leukocytes from 145 donors living in holo- or hyperendemic regions of Africa (Liberia, Gambia, Madagascar) were used for genomic HLA class II typing of their DRB-DQA and DQB genes by means of restriction fragment length analysis (RFLP). No associations between T cell responses and HLA-DR or -DQ alleles or DRB-DQA-DQB haplotypes were seen among the West Africans even when the donors were divided into high, medium or low responders. This was also true for a small group of HLA class II identical Malagasy donors including three pairs of twins. However, while the T cell responses between the twin pairs varied, those within the pairs were similar. Very similar findings were made with antibodies binding to Pf155/RESA peptides. Our data imply that the impact of MHC class II gene products on specific immune responses to Pf155/RESA epitopes is weak and hard to demonstrate in outbred human populations naturally primed by infection. This may be due to genetic regulations by other, non-HLA class II coded factors superimposed on possible HLA class II restrictions.

Adult↗
PubMed1991

Clinical parameters in 74 consecutive patients shunt operated for normal pressure hydrocephalus.

Seventy four consecutive patients diagnosed as normal pressure hydrocephalus (NPH) and operated with a ventriculo-peritoneal shunt were followed prospectively for an average of 2.1 years. The mean age was 64 years. The effect of the operation was estimated by calculating 6 indices expression social functioning, neurological signs, gait ability, continence, psychometric performance and psychiatric condition. Ninety-six % had mental symptoms, 95% gait disturbances and 75% incontinence. Improvement was observed in 78% after shunt surgery, while 22% deteriorated. Psychiatric improvement was seen in 80% and 76% improved in gait ability. Improvement was highest in the group caused by subarachnoid hemorrhage (98%) while 73% with idiopathic NPH improved. Old age was not correlated to poorer response, while long-standing pre-operative symptoms yielded worse results. No single symptom or sign could predict a positive outcome of the operation. Eleven % of the patients could leave long-term care institutions and there was a 36% reduction of aid in daily living. Complications to shunt surgery were observed in 50% of the patients and shunt related mortality was 1%. Shunt malfunction was the most frequent complication (31%) followed by infection (19%). Epilepsy developed in 9% after surgery. All shunt complication except one appeared within the first year after surgery.

Activities of Daily Living↗
PubMed1991

Clinical classification of Swedish snuff dippers' lesions supported by histology.

From a total material of 184 Swedish users of loose packed moist snuff and 68 users of portion-bag packed moist snuff, cases were selected from subgroups based on a four-point clinical grading scale. The selected material for the study comprised 70 cases (ten from each clinical grade group, no Degree 4 lesion was found among portion-bag users). Features recognized in biopsies from these cases together with findings in previous studies correlated well with the use of a four-point scale for the grading of clinical changes, especially in the context of discriminating lesions for which special efforts should be undertaken to make the patient stop or change the snuff dipping habit and for selecting patients in whom regular clinical follow-up including a biopsy should be carried out. In this article is also discussed the labeling of the clinical oral mucosal changes seen at the site where a quid of snuff is regularly placed. The conceptual use of "snuff dippers' lesions" is recommended instead of e.g. snuff-induced leukoplakia.

Adult↗
PubMed1991

Reversibility of snuff dippers' lesion in Swedish moist snuff users: a clinical and histologic follow-up study.

The purpose of this study was to assess possible reversibility of oral mucosal changes, associated with the use of Swedish moist snuff, after change of habit. Biopsies from a total material of 252 regular snuff users, 184 using loose snuff and 68 using portion-bag packed snuff, were screened microscopically to identify histopathologic epithelial changes in addition to, or differing from, those generally seen as a result of snuff use. The main basis for selection of these variables were the criteria of epithelial dysplasia as defined by WHO and the eight histologic features, which have been reported to be the most important discriminators to separate cases with leukoplakia that subsequently developed carcinoma, from those that did not. Twenty-nine subjects, 3 showing Degree 2 lesions, 21 Degree 3 lesions and 5 Degree 4 lesions, all of them loose snuff users were identified. All the 29 users were re-examined clinically and histologically after 3-6 months. The rebiopsy was always secured from the same mucosal area as the original biopsy. At follow-up, 20 subjects had either stopped their snuff habit or changed to portion-bags and changed placement of the quid. All of them showed a healthy mucosa at the previous biopsy site and normal tissue in the histologic examination of the rebiopsies. Seven subjects had changed to portion-bags and variably reduced their daily exposure to snuff. At follow-up they presented with less pronounced clinical changes and the rebiopsies showed evidence of reduced epithelial changes. One major conclusion from this study is that tissue changes, clinically as well as histologically, are reversible following cessation of snuff habit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗