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Biomedical subjects

M Olsson

Publications and source records attributed to M Olsson.

At least 145 records · Page 8Linked to original sources
PubMed1987

Flow cytofluorometry of lysosomal acridine orange uptake by living cultured cells. Effect of trypsinization and starvation.

The uptake of the fluorescent, lysosomotropic weak base acridine orange (AO) by living cells in culture was studied by flow cytofluorometry. A mouse myeloma cell line (SP 2/0), growing in suspension, and an anchorage-dependent human malignant glioma cell line (U-251 MG), brought into suspension by trypsinization, were used. The consequences of trypsinization were also studied using static cytofluorometry. The lysosomal accumulation of AO by myeloma cells growing in suspension was found to be only moderately affected by starvation (i.e. incubation without medium change) for a period of up to five days. Trypsinization of the glioma cells after staining with AO caused pronounced release of the fluorescent dye while trypsinization before staining with AO did not significantly change the average lysosomal concentration of AO. We did, however, notice certain side effects of trypsinization in the form of both increased cellular green fluorescence and greater intercellular variability that reduce the validity of data obtained from cells detached by routine trypsinization. In conclusion, the condition of the lysosomal vacuome of living cultured cells growing in suspension may be studied by flow cytofluorometry after vital staining with the lysosomotropic weak base AO. Anchorage-dependent trypsinized cells, however, yield unsatisfactory results when examined in a flow cytofluorometer system and are better studied while still attached to their substratum, using static cytofluorometry.

Acridine Orange↗
PubMed1987

Enzyme-linked immunosorbent assay of H+,K+-ATPase, the parietal cell antigen.

Vesicular membranes, purified from porcine gastric mucosa and rich in H+,K+-ATPase, were used to establish an enzyme-linked immunosorbent assay (ELISA) for determinations of parietal cell autoantibodies. Results obtained with the ELISA correlated well with standard immunofluorescence determinations of parietal cell antibodies based on frozen sections of rat stomach. The ELISA however was about 10-fold more sensitive than the immunofluorescence method and had high specificity. Intra- and interassay coefficients of variation, determined with a patient sera of average positivity, were 5.5% and 18%, respectively. The ELISA detected antibody binding in 23 out of 26 sera from patients with known autoimmune atrophic gastritis, in five of 25 sera with autoimmune thyroiditis, in five of 20 sera from patients with Graves' disease, in three out of 20 sera from patients with atoxic nodular goitre, in six of 20 sera of patients with primary biliary cirrhosis, in two out of 20 sera of patients with active duodenal ulcer, in two out of 20 sera with detectable antinuclear antibodies, and in one out of 20 sera with detectable rheumatoid factor. Data determined by an ELISA based on a gastric vesicular membrane preparation of human origin correlated well (r = 0.79, P less than 0.001) to those obtained by the standard ELISA based on porcine membrane material. The assay should be well suited for routine determinations of parietal cell antibodies in investigations of autoimmune gastritis and multiple organ autoimmune endocrinopathies.

Adenosine Triphosphatases↗
PubMed1986

Emergency care. Identification of psychosocial problems.

Psychosocial problems are common among emergency department visitors, and can remain undetected if not focused upon. In the present study the magnitude of these problems was analysed by a social worker through telephone interviews 3-5 days after patients emergency department visit. This survey revealed not only those patients recognized by the regular staff as in need of help because of social problems (5%) but also an additional 33% of patients whose problems went undetected. Fifteen percent of the visitors found contact with a social worker to be helpful and six percent requested such help. A follow-up investigation five months after the visit revealed that assistance had been given to 83% of those patients.

Emergency Service, Hospital↗
PubMed1986

Emergency room triage by a medical specialist.

This is an investigation of the impact of an emergency room triage by a medical specialist. The study encompassed patients who came to the medical section of the emergency room of a large university hospital during a two-week study period and a control period of the same length. The result showed that 36% of the patients could be sent home after the triage, thereby reducing the number of chemical tests and ECG examinations significantly (p less than 0.001). In addition, the patient's average treatment period was shortened by a mean of 63 min. No effect of the triage on hospital use of out-patient visits to the hospital during a one year follow-up period was noted. The triage procedure was safe for, and accepted by the patients, as was demonstrated by follow-ups involving investigation of the death register and personal interviews. The study shows that triage by a specialist is an effective method for reducing hospital service utilization and shortening patient treatment time.

Emergency Medical Services↗
PubMed1985

Hepatic and peripheral insulin resistance following streptozotocin-induced insulin deficiency in the dog.

Insulin resistance and insulin deficiency are both present in many patients with diabetes mellitus. We tested the hypothesis that insulin resistance can evolve from a primary lesion of the beta-cell secretory function. Insulin-mediated glucose uptake (insulin clamp), endogenous glucose production, and glucose-stimulated insulin secretion (hyperglycemic clamp) were measured in awake dogs before and four to six weeks after streptozotocin-induced diabetes mellitus. Streptozotocin (30 mg/kg) resulted in a significant rise in the mean fasting plasma glucose concentration from 104 +/- 2 mg/100 mL to 200 +/- 34 mg/100 mL, (P less than 0.05), and a slight decrease in the mean fasting plasma insulin concentration (from 21 +/- 2 microU/mL to 15 +/- 2 microU/mL). Under conditions of steady-state hyperglycemia (+75 mg/100 mL hyperglycemic clamp, insulin secretion was reduced by 75% in the streptozotocin-treated dogs (P less than 0.025), and the total amount of glucose metabolized decreased from 13.56 +/- 1.04 to 4.74 +/- 0.70 mg/min X kg (P less than 0.001). In the postabsorptive state, endogenous glucose production was slightly, although not significantly, higher in the diabetic dogs (3.05 +/- 0.46 v 2.51 +/- 0.22 mg/min . kg), while the glucose clearance rate was 35% lower (P less than 0.001). When the plasma insulin concentration was increased to approximately 45 microU/mL (insulin clamp) while holding plasma glucose constant at the respective fasting levels (99 +/- 1 and 186 +/- 30 mg/100 mL), endogenous glucose production was completely suppressed in control dogs but suppressed by only 51% (1.46 +/- 0.37 mg/min . kg, P less than 0.025) in diabetic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Maternal and cord serum levels of tissue polypeptide antigen (TPA) in normal pregnancies.

The tumor antigen and cytoskeleton protein tissue polypeptide antigen (TPA) have been determined in maternal serum throughout pregnancy. TPA levels in serum from pregnant women (n = 70) were not different from those in nonpregnant women (n = 61) until pregnancy week 28, from which time levels increased until parturition. Duplex pregnancies (n = 7) had higher serum TPA concentrations than simplex pregnancies, which was significant in pregnancy weeks 28 (p less than 0.014) and 32 (p = 0.05). Maternal serum TPA concentrations did not change during abortion or parturition and the mixed umbilical blood concentration of TPA equaled that in the mother's serum just after parturition. The correlation between placenta weight and maternal serum TPA levels was significant (p = 0.025). The decline of TPA after labor indicated a t1/2 for serum TPA of 7.5 days.

Abortion, Induced↗
PubMed1985

Effects of insulin on peripheral and splanchnic glucose metabolism in noninsulin-dependent (type II) diabetes mellitus.

The mechanism(s) and site(s) of the insulin resistance were examined in nine normal-weight noninsulin-dependent diabetic (NIDD) subjects. The euglycemic insulin clamp technique (insulin concentration approximately 100 microU/ml) was employed in combination with hepatic and femoral venous catheterization and measurement of endogenous glucose production using infusion of tritiated glucose. Total body glucose metabolism in the NIDD subjects (4.37 +/- 0.45 mg/kg per min) was 38% (P less than 0.01) lower than in controls (7.04 +/- 0.63 mg/kg per min). Quantitatively, the most important site of the insulin resistance was found to be in peripheral tissues. Leg glucose uptake in the diabetic group was reduced by 45% as compared with that in controls (6.0 +/- 0.2 vs. 11.0 +/- 0.1 mg/kg leg wt per min; P less than 0.01). A strong positive correlation was observed between leg and total body glucose uptake (r = 0.70, P less than 0.001). Assuming that muscle is the primary leg tissue responsible for glucose uptake, it could be estimated that 90 and 87% of the infused glucose was disposed of by peripheral tissues in the control and NIDD subjects, respectively. Net splanchnic glucose balance during insulin stimulation was slightly more positive in the control than in the diabetic subjects (0.31 +/- 0.10 vs. 0.05 +/- 0.19 mg/kg per min; P less than 0.07). The difference (0.26 mg/kg per min) in net splanchnic glucose balance in NIDD represented only 10% of the reduction (2.67 mg/kg per min) in total body glucose uptake in the NIDD group and thus contributed very little to the insulin resistance. The results emphasize the importance of the peripheral tissues in the disposal of infused glucose and indicate that muscle is the most important site of the insulin resistance in NIDD.

Biological Transport↗
PubMed1985

The disposal of an oral glucose load in healthy subjects. A quantitative study.

Although it is an established concept that the liver is important in the disposition of glucose, the quantitative contribution of the splanchnic and peripheral tissues, respectively, to the disposal of an oral glucose load is still controversial. In the present investigation, we have employed the hepatic venous catheter technique in combination with a double-tracer approach (in which the glucose pool is labeled with 3H-glucose and the oral glucose load is labeled with 14C-glucose) to quantitate the four determinants of oral glucose tolerance: rate of oral glucose appearance, splanchnic glucose uptake, peripheral glucose uptake, and suppression of hepatic glucose production. Studies were carried out in 11 normal volunteers in the overnight-fasted state and for 3.5 h after the ingestion of glucose (1 g/kg body wt; range, 55-93 g). In the postabsorptive state, the rate of endogenous (hepatic) glucose production, evaluated from the 3H-glucose infusion, was 2.34 +/- 0.06 mg/min X kg. Glucose ingestion was accompanied by a prompt reduction of endogenous glucose output, which reached a nadir of 0.62 +/- 0.23 mg/min X kg at 45 min and remained suppressed after 3.5 h (0.85 +/- 0.22 mg/min X kg). The average inhibition of hepatic glucose output during the absorptive period was 53 +/- 5%. The appearance of ingested glucose in arterial blood, as derived from the 14C-glucose measurements after correction for recycling 14-C radioactivity, reached a peak after 15-30 min, and 14C-glucose continued to enter the systemic circulation throughout the observation period. The rate of appearance of ingested glucose was 2.47 +/- 0.45 mg/min X kg at 3.5 h. A total of 73 +/- 4% of the oral load was recovered in the systemic circulation within 3.5 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1984

Cytofluorometric quantitation of acridine orange uptake by cultured cells.

The vacuolar accumulation of the lysosomotropic weak base acridine orange (AO) within living cells in culture was studied by cytofluorometry. Mouse peritoneal macrophages, malignant human glioma cells, and normal human glial cells were utilized. Exposure to AO resulted in granular bright red fluorescence, as well as a diffuse weak green background fluorescence. To obtain reproducible "staining" conditions, the red granular fluorescence was measured as a function of dye concentration and staining time. Exposure to high concentrations of AO (greater than 10 micrograms/ml) was found to cause cell damage in combination with markedly changed fluorescence distribution for the cell population with reduced mean fluorescence and increased variability. Granular uptake of AO was pH-dependent and almost zero at pH 5.5. AO fluorescence, as measured by cytofluorometry, was found to be roughly linear to the amount of AO present in the cells, as measured by spectrofluorometry after cell solubilization, indicating negligible fluorescence quenching. AO labelling of living cells might serve as a useful indicator of the condition of the cellular vacuolar (lysosomal) apparatus.

Acridine Orange↗
PubMed1984

Studies on thymocyte subpopulations in guinea pigs. IV. A subpopulation sensitive to a natural, cold reactive cytotoxic factor in autologous serum.

Guinea pig serum was shown to be cytotoxic against a subpopulation of autologous thymocytes. The sensitive cells belonged to the population of small, high-density cells, constituting the majority of cortical thymocytes. In this respect, the activity resembled that of some heterologous sera tested (rat, rabbit) and allogeneic serum. The same population was also particularly reactive in rapid early (RE) migration [Sandberg, 1981] induced by rat serum. Human serum differed from other tested sera both as regards cytotoxicity and RE migration. The cytotoxic effect of autologous serum was demonstrated at 4 degrees C, whereas it was absent at 37 degrees C. The latter is in contrast to the cold reactive thymocytotoxic autoantibodies previously described in some mouse strains, and it is also in contrast to thymocytotoxic factors in heterologous serum. In all tested sera, the activity was completely inhibited by incubation at 56 degrees C for 30 min. The results may be relevant for the understanding of normal cell death in the thymus, and are discussed in relation to lymphocytotoxic autoantibodies in various disease states in man and animals.

Animals↗
PubMed1982

Repair of alkylated DNA in Escherichia coli. Physical properties of O6-methylguanine-DNA methyltransferase.

An inducible methyltransferase of Escherichia coli acts on O6-methylguanine in DNA by conveying the methyl group to one of its own cysteine residues. The protein has now been purified to apparent homogeneity from a constitutively expressing strain. The homogeneous methyltransferase exhibits no DNA glycosylase or endonuclease activity on alkylated DNA. Further, the methyltransferase activity is strikingly resistant to heat inactivation under reducing conditions. The protein has Mr = 18,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while the sedimentation coefficient and Stokes radius of the native enzyme yield Mr = 18,400. The amino acid composition of the purified protein shows 4 to 5 cysteine residues/transferase molecule. The methylated, inactive form of the transferase has an unaltered molecular weight.

Amino Acids↗