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Biomedical subjects

A Lindgren

Publications and source records attributed to A Lindgren.

At least 19 recordsLinked to original sources
PubMed1992

Requirement for coenzyme Q in plasma membrane electron transport.

Coenzyme Q is required in the electron transport system of rat hepatocyte and human erythrocyte plasma membranes. Extraction of coenzyme Q from the membrane decreases NADH dehydrogenase and NADH:oxygen oxidoreductase activity. Addition of coenzyme Q to the extracted membrane restores the activity. Partial restoration of activity is also found with alpha-tocopherylquinone, but not with vitamin K1. Analogs of coenzyme Q inhibit NADH dehydrogenase and oxidase activity and the inhibition is reversed by added coenzyme Q. Ferricyanide reduction by transmembrane electron transport from HeLa cells is inhibited by coenzyme Q analogs and restored with added coenzyme Q10. Reduction of external ferricyanide and diferric transferrin by HeLa cells is accompanied by proton release from the cells. Inhibition of the reduction by coenzyme Q analogs also inhibits the proton release, and coenzyme Q10 restores the proton release activity. Trans-plasma membrane electron transport stimulates growth of serum-deficient cells, and added coenzyme Q10 increases growth of HeLa (human adenocarcinoma) and BALB/3T3 (mouse fibroblast) cells. The evidence is consistent with a function for coenzyme Q in a trans-plasma membrane electron transport system which influences cell growth.

Cell Division↗
PubMed1992

Hyperhomocysteinaemia in stroke: prevalence, cause, and relationships to type of stroke and stroke risk factors.

Moderate hyperhomocysteinaemia is a frequent finding in atherothrombotic cerebrovascular disease. This study confirms and extends this observation. Hyperhomocysteinaemia was present in 57 of 142 survivors with stroke (40%) and in four of 66 controls (6%). Plasma homocysteine concentrations were increased not only in carotid artery disease or lucunar stroke but also in haemorrhagic or embolic strokes. Homocysteine values were unrelated to the presence of hypertension, smoking, or hypercholesterolaemia, or to the concentrations of blood glucose, glycosylated haemoglobin, and plasma fibrinogen. Multiple regression analysis of the patient data showed that about 40% of the variation in plasma homocysteine concentrations could be predicted by the values for the homocysteine metabolism cofactors, blood folate and plasma pyridoxal 5-phosphate and by renal function as reflected in the values for serum creatinine. In patients, urine excretion of homocysteine per unit creatinine was significantly increased and strongly correlated both to the plasma homocysteine concentration and to the values for blood folate, plasma pyridoxal 5-phosphate, and serum vitamin B12. We conclude that moderate hyperhomocysteinaemia is frequently present in cases of stroke, is independent of other stroke risk factors or the type of stroke, and is partly related to renal function and the concentrations of homocysteine metabolism cofactors.

Adult↗
PubMed1992

Plasma lipids and lipoproteins in subtypes of stroke.

We determined plasma lipid and lipoprotein concentrations in 131 patients (95 males, 36 females, mean age 71 years) 6 months after acute stroke onset. Compared to a reference population, the alterations of plasma lipid concentrations in stroke patients were moderate. However, the stroke patients had higher levels of triglyceride and lipoprotein (a) and lower concentrations of cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol. Patients with different subtypes of stroke showed significant differences when compared with each other by analysis of covariance (with adjustment for age, sex, smoking, hypertension and diabetes). Patients with carotid or vertebral artery disease had the higher levels of cholesterol, triglyceride and apolipoprotein B, whereas high density lipoprotein triglyceride concentrations were higher in patients with cardioembolic infarcts.

Adult↗
PubMed1992

Elevated urinary beta-hexosaminidase in patients with stroke.

Urinary beta-hexosaminidase is a sensitive indicator of renal damage. The urinary excretion of this enzyme was measured in 31 patients with ischaemic stroke in the acute phase and in 126 patients 21-43 weeks after their stroke. Both immediately and after 21-43 weeks the patients showed a similar and a significantly increased level of urinary beta-hexosaminidase. This indicates the presence of renal injury in the stroke patients, which in turn might reflect a generalized vascular disease.

Biomarkers↗
PubMed1992

Age as a determinant of axillary node involvement in invasive breast cancer.

We analyzed the age at diagnosis and the tumor size as determinants of axillary node involvement in 725 consecutive patients with breast cancer. The prevalence of nodal involvement increased consistently with tumor diameter from 18.9% in tumors smaller than 10 mm to 72.9% in those measuring 40 mm, or more. The risk also varied with age, the lowest prevalence being found in the youngest and the oldest patients and the highest one in the 40-59-year age group. When analyzed as a continuous variable age was best fitted as a second order term and it was a statistically significant (p = 0.04) determinant of axillary metastases in a multivariate model where tumor diameter, histopathological classification and estrogen receptor concentration were taken into account as possible confounding variables. The findings indicate that the parallelism between the establishment of metastases in lymph nodes and at distant sites may vary with age. The prognostic value of nodal status may therefore depend on age at diagnosis.

Adult↗
PubMed1991

Inhibition of transplasma membrane electron transport by monoclonal antibodies to the transferrin receptor.

Reduction of iron in diferric transferrin is inhibited by monoclonal antibodies to the transferrin receptor which bind at sites other than the high affinity transferrin binding site. These antibodies include B3/25, GB16 and GB22. Two antibodies which bind at the high affinity site for transferrin, 42/6 and GB18, do not inhibit iron reduction by transplasma membrane electron transport. The results are consistent with the proposal that differric transferrin reduction or stimulation of transmembrane NADH oxidase activity involves a site different from the high affinity diferric transferrin binding site. A synergistic action of antibodies with epitopes at the tight binding site involved in iron uptake and the antibodies which inhibit electron transport, B3/25 and GB16, can explain the increased inhibition of growth observed when both 42/6 and B3/25 are added to proliferating cells.

Animals↗
PubMed1991

Modification of transplasma membrane oxidoreduction by SV40 transformation of 3T3 cells.

Transformation of 3T3 cells by SV40 virus changes the properties of the transplasma membrane electron transport activity which can be assayed by reduction of external ferric salts. After 42 h of culture and before the growth rate is maximum, the transformed cells have a much slower rate of ferric reduction. The change in activity is expressed both by change in Km and Vmax for ferricyanide reduction. The change in activity is not based on surface charge effect or on tight coupling to proton release or on intracellular NADH concentration. With transformation by SV40 virus infection the expression of transferrin receptors increases, which correlates with greater diferric transferrin stimulation of the rate of ferric ammonium citrate reduction in transformed SV40-3T3 cells than in 3T3 cells.

3T3 Cells↗
PubMed1991

Intestinal and diffuse types of gastric cancer: secular trends in Sweden since 1951.

In order to test the hypothesis that the general decline in gastric cancer observed in many countries is due to a selective decline in Laurén's intestinal type, we re-examined all 427 histologic sections obtained from gastric carcinomas diagnosed at the Department of Pathology, University Hospital, Uppsala, Sweden, in 1951, 1961, 1971-72 and 1981. The relative proportions of intestinal and diffuse type cancers were compared. The intestinal type was significantly (P less than 0.001) more common among elderly people than in the younger age groups. The relative proportions of intestinal type carcinoma in the four periods under study were 65%, 55%, 42% and 60%, respectively. The absence of any clearly discernible trend over time contradicts the hypothesis of diverse secular trends for intestinal and diffuse types of gastric carcinoma.

Age Factors↗
PubMed1991

Longitudinal study of seroreactivities to Pf155/RESA and its repetitive sequences in small children from a holoendemic area of Liberia.

The seroreactivities to Pf155/RESA antigen and to three oligopeptides (EENV)2, EENVEHDA and K(DDEHVEEPTVA)2, which constitute repeat subunits of the RESA molecule, were investigated between 1980 and 1986 in two cohorts of children (n = 114) with and without monthly chemosuppression (pulsed reduction of parasite load) against malaria from six months to five years of age during development of protective immunity. Serum samples were collected first at half-yearly and then yearly intervals. Positive immunofluorescence against Pf155/RESA (EMIF) was only found in 24% of the samples. The children with chemosuppression were more often seropositive (30%) than the non prophylactic children (17%). This was in contrast to the seroreactivity against crude parasitic antigens which was highest in the non prophylactic children. In these children, there was a general decrease of EMIF titres around two years of age. Immunosuppression by chronic parasitaemia may be suggested as a reason for this. ELISA seroreactivity was found against one, two or three oligopeptides in all children with high EMIF titres (greater than 250) although (EENV)2 appeared to best correlate (92%) with the EMIF seropositivity. While EMIF seropositivity only showed partial correlation to immunoprotection against patent parasitaemia in the non prophylactic children, the individual profiles of the seroreactivities to the different specific epitopes of the Pf155/RESA molecule and their relevance with regards to protective immunity to malaria need to be investigated further.

Amino Acid Sequence↗
PubMed1990

Pretreatment serum levels of CA-125, carcinoembryonic antigen, tissue polypeptide antigen, and placental alkaline phosphatase, in patients with ovarian carcinoma, borderline tumors, or benign adnexal masses: relevance for differential diagnosis.

Pretreatment serum levels of the antigens CA-125, tissue polypeptide Antigen (TPA), carcinoembryonic antigen (CEA), and placental alkaline phosphatase (PLAP) were determined in samples from 295 women with adnexal masses. At laparotomy 48% of patients had epithelial ovarian carcinoma, 9% had tumors of low malignant potential, and 8% suffered from malignancies of other kinds. The sensitivity of CA-125 with 35 U/ml as the cutoff was 88% in women with ovarian carcinoma, but 74% among those with limited disease and 58% in borderline malignancy. Only 6 of 17 mucinous ovarian carcinomas were detected. Specificity was 83%. CEA was elevated above 5.0 micrograms/liter in 15 of 17 patients with mucinous ovarian cancer. TPA detected advanced stages of malignancy, but the sensitivity was low, 53%, in cases with limited disease. PLAP was elevated in 46% of ovarian carcinoma patients. For detecting malignancy overall, the use of a parallel combination of the CA-125 and CEA assays was more sensitive than use of CA-125 as a single marker. This test combination may be of value in the diagnosis of adnexal masses. The predictive value of a positive result was 90%, and that of a negative result, 76%.

Adnexal Diseases↗
PubMed1990

Pretreatment serum levels of CA-125, carcinoembryonic antigen, tissue polypeptide antigen, and placental alkaline phosphatase in patients with ovarian carcinoma: influence of histological type, grade of differentiation, and clinical stage of disease.

Pretreatment serum levels of the tumor-associated antigens CA-125, tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), and placental alkaline phosphatase (PLAP) were analyzed in 142 patients with epithelial ovarian carcinoma, and related to clinical and histopathological parameters. In a linear multiple regression model CA-125 serum levels were profoundly influenced by the type of tumor, i.e., mucinous or nonmucinous. Clinical stage also had significant impact, whereas grade of differentiation did not, when the other two factors were taken into account. CEA levels were also dependent mainly on histological type. Mucinous tumor cases had high levels. Only clinical stage or tumor burden had a significant impact on TPA levels. PLAP levels were significantly influenced by histological type of tumor and by grade of differentiation but not by clinical stage. The dependence of CA-125 levels upon clinical stage was evident only in nonmucinous tumors. Furthermore, size of the primary tumor was not important for the CA-125 value, in contrast to FIGO stage. Thus CA-125 is primarily a sensitive indicator of disseminated disease in ovarian carcinoma patients. On the basis of the CA-125 level it was possible to predict the extent of disease with an overall accuracy of 55%. If TPA and CEA levels were also considered, the predictive accuracy was 63%.

Alkaline Phosphatase↗
PubMed1990

Liver involvement in Addison's disease.

Three patients admitted because of slightly increased serum aminotransferases were found to have Addison's disease. A review of 16 other patients with Addison's disease who had serum aminotransferase activity [aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT)] determined prior to treatment revealed one more patient with slightly increased aminotransferase activity that could not be explained by known causes of increased serum aminotransferase levels. In all four of these patients, the enzymes normalized within 1 wk of corticosteroid substitution treatment. Liver biopsy in one patient revealed discrete lymphocytic infiltrates in the portal zones. On the basis of these observations, we recommend that the possibility of Addison's disease should be considered in patients with obscure slight hypertransaminasemia.

Addison Disease↗
PubMed1979

Adamantinoma tibiae.

A case with characteristic roentgenographic and microscopic findings of adamantinoma tibiae is reported. Knee disarticulation with early ambulation is the treatment of choice and was performed on this patient. Limb ablation followed by Unna Paste Bandage to prevent oedema and permit early prosthetic fitting facilitates rehabilitation. The 1 year follow-up showed excellent prosthetic function and no evidence of residual tumour.

Adult↗