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Biomedical subjects

G Ronquist

Publications and source records attributed to G Ronquist.

At least 163 records · Page 9Linked to original sources
PubMed1987

Seminal plasma levels of fucosyltransferase, galactosyltransferase and sialyltransferase in normospermic and oligospermic men.

The activities of fucosyltransferase, galactosyltransferase, and sialyltransferase were estimated in ultracentrifuged seminal plasma samples from normospermic and oligospermic men. There was no significant difference with regard to these activities between the two groups. Hence, fucosyltransferase activity was high in both normospermic (mean value: 190.2 nmol/l) and oligospermic men (mean value: 157.2 nmol/l) and exceeded that of blood plasma (mean value: 7.6 nmol/l) by 20-25 times. On the contrary, the activity ratio between seminal plasma and blood plasma of galactosyltransferase and sialyltransferase was low and fairly close to 1. A significant correlation was noted between seminal plasma galactosyltransferase activity and semen volume only in normospermic men. Significant inverse correlations in oligospermic men were observed between seminal plasma sialyltransferase activity and sperm concentration (and total sperm count) as well as between galactosyltransferase and fucosyltransferase activities.

Adult↗
PubMed1987

Phospholipase A2 activity in prostasomes from human seminal plasma.

Phospholipase A2 (PLA2) activity was measured and partially characterized in prostasomes isolated from human seminal plasma. The results show high PLA2 activity in seminal plasma with a threefold enrichment in the isolated prostasomes. Highest activity was found at pH 8.0 and 10.5, and there was an absolute requirement for calcium with almost total inhibition of PLA2 activity in the presence of 1 mM EDTA. Analysis with two-dimensional gel electrophoresis of prostasome material revealed a complex protein pattern with most of the proteins in the molecular weight interval of 10,000-90,000 daltons. The possible role of PLA2 in prostasomes is discussed.

Electrophoresis, Polyacrylamide Gel↗
PubMed1987

Myocardial high-energy phosphates, lactate and pyruvate during moderate or severe normothermic ischemia in rat hearts perfused with phosphoenolpyruvate and ATP in cardioplegic solution.

Rat hearts were subjected to normothermic ischemia for 15 min (group I) or 30 min (group II). During the ischemic period the hearts were perfused twice with cardioplegic solution supplemented with 14.4 mM phosphoenolpyruvate (PEP) and/or 0.067 mM adenosine triphosphate (ATP), and at the end of ischemia they were freeze-clamped. The myocardial ATP content in group I fell to about 55% of normal values except in hearts supplemented with only PEP, which showed greater reduction. In group II the ATP fell to only about 5% of normal values, without significant differences between the subgroups Hearts supplemented with PEP alone or with combined PEP-ATP showed significantly higher levels of pyruvate than in hearts with only ATP supplementation or control hearts. The study thus demonstrated clear difference in ATP content between moderate and severe ischemic trauma. The high pyruvate levels after PEP supplementation indicate formation of pyruvate without concomitant lactate increase.

Adenine Nucleotides↗
PubMed1987

Cerebral damage during open-heart surgery. Clinical, psychometric, biochemical and CT data.

The incidence and extent of cerebral damage following open-heart surgery were prospectively investigated in 103 patients, using clinical assessment, psychometry, adenylate kinase analysis in cerebrospinal fluid (CSF-AK) and computed tomography (CT) of the brain. The surgical mortality was 1.9%. Clinically there was obvious cerebral dysfunction in four cases, subtle evidence of brain damage (mainly undue fatigue) in 16 and no evidence in 81 cases. In the 16 patients the mean CSF-AK was substantially increased (0.122 U/l) and the psychometric performance distinctly impaired (-12 points) postoperatively; in the 81 patients the figures were 0.55 U/l and -3.4. Psychometrically, 60% of the patients showed cerebral dysfunction, which was pronounced in 16%. CSF-AK analysis indicated cerebral damage as absent or trival in 45%, moderate in 33% and marked in 22%. CT revealed postoperative cerebral infarction in two cases. Results from the various methods showed reasonable correlation, but also considerable overlap. Open-heart surgery thus can cause brain damage additional to that neurologically discernible. Fatigue is an important sign in this context. In research on postoperative brain damage, the relative insensitivity of routine neurologic investigation calls for supplementary, refined methods.

Adenylate Kinase↗
PubMed1987

Interrelated effects of nucleoside mono- and triphosphates and phosphoenolpyruvate on rat hearts subjected to cardioplegic arrest at normothermia.

Supplementation with phosphoenolpyruvate (PEP) and ATP was previously found to enhance the protective effect of potassium cardioplegia on rat hearts subjected to extensive ischemic trauma (30 min at 37 degrees C) in the paracorporeal rat heart model. In the present experiments, the ischemia time was reduced to 20 min (37 degrees C). Ventricular work after ischemia was best in control rats with potassium cardioplegia only. Supplementing the cardioplegic solution with PEP and ATP (group I) resulted in significantly reduced postischemic ventricular work and increased efflux of the creatine kinase isoenzyme MB (CK-MB). The same result was obtained when adenosine monophosphate (AMP) was added to the supplementation (group II). When guanosine monophosphate (GMP) was added instead of AMP (group III), the negative effects of PEP and ATP in the cardioplegic solution were partly abolished. Plain potassium cardioplegia, without additives, nevertheless gave the best results. There were no significant intergroup differences in the myocardial content of adenine nucleotides. The results contrasted with those in the previous study of more protracted ischemic trauma (30 min at 37 degrees C) and possible explanations are discussed.

Adenosine Monophosphate↗
PubMed1987

Metabolic and functional effects of creatine phosphate in cardioplegic solution. Studies on rat hearts during and after normothermic ischemia.

Creatine phosphate is a precursor molecule for ATP synthesis, even under ischemic conditions. We investigated its functional and metabolic effects when added to cardioplegic solution. Rat hearts were subjected to normothermic ischemia for 15 or 30 min and then freeze-clamped. During ischemia there was gradual reduction of high-energy phosphates, but the hearts with creatine phosphate supplement showed higher myocardial content of ATP and of the creatine compound. Other hearts, subjected to 20 min of ischemia, were reperfused with blood for 40 min. Creatine phosphate supplementation resulted in better left ventricular isovolumic work during spontaneous activity, but in paced activity (400 beats/min) no significant differences were seen. After reperfusion, supplemented hearts showed a tendency to higher levels of ATP and creatine phosphate. In all three groups the hearts with cardioplegic supplement had significantly increased myocardial content of pyruvate without proportional lactate increase. The results indicate that creatine phosphate may be an effective constituent in cardioplegic solution.

Animals↗
PubMed1986

Aberrant protein pattern in red cell membranes of a patient with mild hemolytic anemia.

A 17-year-old patient with mild hemolytic anemia known since early childhood displayed an aberrant protein pattern of his red cell membranes when analyzed in SDS-polyacrylamide gel electrophoresis (SDS-PAGE). A double protein band in the low molecular weight region (molecular weight of about 33,000) was distinctly reduced or missing in the membranes that were investigated concomitantly with those of controls on two occasions at an interval of 6 months'. The phosphorylation pattern of membrane phosphoproteins, on the other hand, did not seem to differ from that of controls. It is suggested that a causal relationship existed between the observed membrane abnormality and the mild hemolytic anemia.

Adolescent↗
PubMed1986

Enhanced protection of rat hearts during ischemia by phosphoenolpyruvate and ATP in cardioplegia.

The paracorporeal rat heart model was used to investigate the extent of myocardial protection by potassium cardioplegia supplemented with phosphoenolpyruvate (PEP) (14.4 mM) and ATP (0.067 mM) singly or in combination. Rat hearts were subjected to 30 minutes of ischemia at 37 degrees. They were subsequently reperfused for 40 minutes during which time the left ventricular isovolumic work was measured and blood samples were taken for creatine kinase isoenzyme MB (CK-MB) analysis. At the end of each experiment the hearts were freeze-clamped for later analyses of high energy phosphate compounds. Supplementation with PEP and ATP (Group I) and with only ATP (Group II) showed a significantly better left ventricular isovolumic work and a significantly higher adenylate charge potential (ACP). Supplementation with only PEP (Group III) resulted in significantly better left ventricular isovolumic work than the control group but significantly lower than groups I and II. There were no significant differences between the groups in regard to the CK-MB efflux. Supplementation with PEP and ATP in combination did not show any positive effect at 40 minutes of reperfusion over and above that which was achieved with ATP only.

Adenosine Triphosphate↗
PubMed1986

Myocardial energy metabolism during mitral valve replacement.

To elucidate the metabolic changes during a relatively short ischemic period, papillary muscle excisions were investigated in 38 patients operated for mitral valve replacement. The overall mean age was 62 years, in 27 women and 11 men. Two excisions were made during ischemia, the first after 13 minutes and the second after 48 minutes of aortic occlusion. These excisions were analyzed for adenine nucleotide, creatine phosphate, lactate and pyruvate contents. The results indicated an ongoing metabolism with an accumulation of lactate, and also influences on the energy charge. For example, although the content of ATP was unchanged between the excisions, the relation to creatine phosphate, as a source for ATP level maintenance, was altered. This is of clinical importance since cardioplegia and hypothermia (myocardial temperature below 20 degrees C) were employed and the interval between the excisions was only 35 minutes on average. Although no significant decrease in myocardial ATP took place, 31 of 38 patients needed inotropic support to wean them off bypass. On the basis of the present results further efforts seem necessary to improve myocardial preservation techniques.

Adenine Nucleotides↗
PubMed1986

Determination of sialic acid residues in transferrin by oxidative-reductive immunoassay.

A method is described for the determination of sialic acid residues in glycoproteins displaying microheterogeneity in the sugar residue. The new method is based on combining an oxidative-reductive step with binding of the glycoprotein to an immunoadsorbent. After a mild oxidation with sodium metaperiodate the sugar is reduced with labeled sodiumborotritide. The chemical modification of the sugar residues does not seem to impair the binding of glycoprotein to the immunoadsorbent. The procedure, which has been elaborated for human transferrin, can be carried out in the presence of other substances in body fluids.

Antigen-Antibody Complex↗
PubMed1985

The prostasome: its secretion and function in man.

An intact organelle, the prostasome, is secreted by the acinar epithelial cell of the human prostate gland. The ultrastructural location of the prostasome is within membrane-bound storage vesicles in the epithelial cells. Prostasomes are delivered into the glandular lumen by an exocytotic event, which is preceded by fusion of adjacent membranes belonging to the storage vesicle and the epithelial cell. Alternatively, the storage vesicle can be translocated in toto from the cell interior into the acinar lumen through the plasma membrane. This latter event has been designated diacytosis. Both phenomena seem to occur with approximately equal frequency in the human prostate gland. An ATPase system that is Mg2+ and Ca2+-dependent is firmly linked to the membranes encasing the prostasomes. The ATPase system may be the molecular basis for vectorial transport of calcium into these organelles. Also a protein kinase activity is located in the membranes. An increase in membrane thickness was observed on phosphorylation. The physiologic function of the prostasomes is not known. They may be important for promoting forward motility of spermatozoa.

Adenosine Triphosphatases↗
PubMed1985

Serum sialyltransferase and fucosyltransferase activities in patients with multiple myeloma.

A significant elevation of serum sialyltransferase and fucosyltransferase mean activities was observed in 19 untreated patients with multiple myeloma. However, sialyltransferase mean activity was significantly lower in 13 other patients treated for 1-30 months with alkylating drugs and prednisolone. Such a definite decrease in serum enzyme activity on treatment was not recorded for fucosyltransferase. Instead, this activity was significantly increased in treated patients as compared to controls. The presenting clinical features of the 32 patients with multiple myeloma were the basis for a clinical staging system with regard to myeloma cell burden according to established criteria. In untreated patients (as opposed to treated ones), a significantly higher serum sialyltransferase (but not fucosyltransferase) activity was obtained among those 11 belonging to stage III than among the other eight with stages I and II, suggesting a link between tumour burden and enzyme activity. This assumption was further strengthened in those six patients followed lengthwise with regard to serum sialyltransferase activity. Concomitantly with objective evidence of change in tumour burden they showed corresponding alterations in sialyltransferase activity. The determination of sialyltransferase and fucosyltransferase activity in serum may be an additional contribution to refine initial assessment and follow-up of individual patients with multiple myeloma.

Aged↗
PubMed1985

Dementia--and adenylate kinase activity in cerebrospinal fluid.

Adenylate kinase (AK) was determined in a lumbo-cisternal cerebrospinal fluid (CSF) gradient and in CSF from patients with mental deterioration. AK activity was unchanged in the gradient and different from albumin and albumin ratio (alb CSF/albumin serum), a blood-brain barrier marker in the same gradient. No differences between normal pressure hydrocephalus, multiinfarct dementia and dementia of the Alzheimer type could be found with regard to adenylate kinase activity in CSF.

Adenylyl Cyclases↗
PubMed1985

Studies of biochemical markers in cerebrospinal fluid in patients with meningoencephalitis.

Several biochemical markers in the cerebrospinal fluid (CSF) of 120 patients with serous meningoencephalitis (SM) of viral origin were compared with those of 74 patients with viral or bacterial infections accompanied by neck stiffness but no CSF abnormality (i.e., meningism). CSF adenylate kinase was higher (P less than 0.025) in SM and correlated with lactate concentration (r = 0.37; P less than 0.01). CSF hypoxanthine was lower (P less than 0.001) in SM, whereas CSF xanthine was similar in the two conditions. The xanthine/hypoxathine ratio correlated with the CSF leukocyte count (r = 0.32; P less than 0.01), and especially with the mononuclear cell count (r = 0.45; P less than 0.001). CSF adenylate kinase correlated with fever in SM (r = 0.28; P less than 0.01). CSF urate and protein displayed a mutual correlation in both conditions (r = 0.26 and P less than 0.05 for SM; r = 0.55 and P less than 0.001 for meningism). These results support the hypothesis of impaired brain cell metabolism, probably of ischemic nature, in viral meningoencephalitis, causing leakage of adenylate kinase into the CSF, where hypoxanthine may be reutilized by mononuclear leukocytes.

Adenylate Kinase↗
PubMed1985

Demonstration of galactosyltransferase activity in human seminal plasma and its relation to sperm penetration in cervical mucus.

The galactosyltransferase activity was determined in seminal plasma from 24 men with various sperm characteristics subdivided in three different groups and from 9 men subjected to vasectomy for the purpose of voluntary sterilization contributing a 4th group. The galactosyltransferase displayed an obligatory dependency on manganese ions for activity. Endogenous glycoproteins of human seminal plasma were poor acceptors for the galactosyltransferase reaction, and a more than 40-fold increase in activity was achieved in the presence of ovomucoid as exogenous acceptor. There were no significant intergroup differences with regard to galactosyltransferase activity. Hence, qualitative and quantitative discrepancies of spermatozoa were not influential on galactosyltransferase activity in a decisive way. An overall positive correlation was registered between galactosyltransferase activity and sperm penetration in cervical mucus (r = 0.53; p less than 0.01).

Cervix Mucus↗