Search PubMed⌕ Search

Biomedical subjects

G Ronquist

Publications and source records attributed to G Ronquist.

At least 235 records · Page 13Linked to original sources
PubMed1979

Adenylate kinase activity and glutathione concentration of cerebrospinal fluid in different neurological disorders.

Adenylate kinase activity and glutathione concentration were measured in cerebrospinal fluid (CSF) of 64 consecutive patients admitted for various neurological disorders. These two analyses were performed in addition to conventional examination of the CSF. Neurological symptoms most probably connected in some cases with no and in others with only subtle changes in the central nervous system were linked to no or only moderate activities of adenylate kinase together with no glutathione. 1 patient with meningioma had no adenylate kinase activity at all while 3 patients with malignant brain tumours showed clear activities similar to 3 patients with well established diagnoses of multiple sclerosis. On the contrary, glutathione was absent in CSF of the patients with brain tumours and multiple sclerosis. Various cerebrovascular diseases involving larger areas of the brain tissue resulted in clear adenylate kinase activities in CSF either alone as in 11 of the patients with cerebral infarction or in combination with the appearance of also glutathione as in the remaining 7 patients with cerebral infarction as well as in the 14 patients studied with hemorrhages of the brain.

Adenylate Kinase↗
PubMed1979

Cerebrospinal fluid content of adenylate kinase, lactate and glutathione in patients with meningitis.

Adenylate kinase activity and lactate concentration were measured in the cerebrospinal fluid (CSF) of 5 patients with bacterial meningitis, of 4 patients with probable bacterial meningitis, and of 18 patients with serous meningitis. Furthermore, for comparison measurements were also performed in CSF of 27 patients with meningism. Concomitantly glutathione was measured in CSF in most of the patients. Significantly higher values of these 3 parameters were found in the CSF of patients with bacterial and probable bacterial meningitis compared with those having serous meningitis and meningism. Adenylate kinase activity and lactate concentration in patients with serous meningitis were significantly higher than in those with meningism. All patients with a clinical diagnosis of meningitis studied so far also displayed an adenylate kinase activity in their CSF. The determination of adenylate kinase, lactate and glutathione levels in CSF might be a useful aid for the diagnosis not only of meningitis but also for the discrimination between bacterial and serous meningitis.

Adenylate Kinase↗
PubMed1978

The in vivo transport of 14C-alpha aminoisobuturic acid into mouse blastocysts during activation for implantation.

The in vivo transport of 14C-AIB (14C-alpha-aminoisobuturic acid) into mouse blastocysts was studied during activation for implantation. Mice, kept in experimentally delayed implantation, were given estrogen to induce implantation and then injections of 14C-AIB i.v. at 0, 4 and 8 h after the estrogen. After in vivo incubation times for 1/3 or 4 h with the labeled amino acid the blastocysts were flushed out of the uterus and collected. A distinct uptake of 14C-AIB occurred in the blastocysts 8 h (the highest uptake) and 12 h after the induction, provided that the in vivo incubation time was 4 h. At these times the blastocysts are lying free in the uterine lumen and consequently there is a transport of 14C-AIB from the epithelium via the uterine secretion into the blastocysts. This uptake indicates that amino acids transported by the system A are important nutrients during early activation. The uptake and retention of 14C-AIB in the uterus was tested at 4 and 8 h after the induction of implantation. The highest uptake was observed when the labeled amino acid was given at 8 h while the longest retention time occurred when 14C-AIB was given at 4 h. Since the transport ratio between the blastocysts and the uterine tissue is not maintained constant it is concluded that the metabolic rates for 14C-AIB transport are different for the uterus and the blastocysts. The AIB transport into uterine tissue preceeds that into the blastocysts. The AIB transport into the blastocysts is maintained as long as they have a negative surface charge.

Aminoisobutyric Acids↗
PubMed1978

Phosphoryl group transfer from Ehrlich cells prelabeled in vivo with (32P)-orthophosphate and (14C)-glucose to unlabeled glioma cells.

A transfer of (32P)-labeled phosphoryl groups has been demonstrated to occur between prelabeled Ehrlich cells (donor cells) and glioma cells (acceptor cells). The Ehrlich cells were generally prelabeled in vivo by an intraabdominal injection of (32P)-orthophosphate 24 hours prior to scarifice of the tumor-bearing mice. In some experiments two injections of (14C)-glucose were given to the animals in addition to the injection of (32P)-orthophosphate prior to sacrifice. The prelabeled Ehrlich cells were mixed with the glioma cells, that were still attached to the culture plates, and incubation took place in vitro. Labeled (32P)-phosphoryl (14C)-serine was isolated from the glioma cells as well as from the Ehrlich cells. The 32P/14C-ratio of (32P)-phosphoryl (14C)-serine of the glioma cells (acceptor cells) was significantly higher than found for the Ehrlich cells (donor cells). This was indicative of an interactive mechanism between the cells partly due to binding of membrane fragments from the Ehrlich cells on to the surface of the glioma cells and partly due to a phosphoryl group transfer between the two types of cells. Interaction experiments with a plasma membrane fraction prepared from the prelabeled Ehrlich cells vis à vis the glioma cells clearly showed that the phosphoryl group transfer mechanism between the cells was dominating and only a minor part of the interaction was due to adhesion. This transphosphorylation reaction represents a new type of interaction between cells. It was not influenced by either adenosine 3', 5'-monophosphate or adenosine 5'-diphosphate.

Animals↗
PubMed1978

Human red cell content of cyclic nucleotides and cations upon beta-adrenergic blockade.

The content of cyclic nucleotides (cAMP, cGMP) and Mg2+, Zn2+,Na+ and K+ was determined in human erythrocytes and after beta-adrenergic blockade in healthy individuals. The figures for cAMP and cGMP were 4.20 and 3.36 nmoles/ l intracellular volume, respectively. Only slight effects on the cyclic nucleotide content as well as on cation content were seen upon beta-blockade in the erythrocytes. It is concluded that the single determination of red cell cAMP is not a sufficient indicator of beta-adrenergic blockade. The determination of cAMP in combination with cGMP, Zn2+ and Na+ might reflect a beta-adrenergic blockade.

Adolescent↗
PubMed1977

Restoration of detergent-inactivated adenosine triphosphatase activity of human prostatic fluid with concanavalin A.

A stimulation by concanavalian A OF Mg2+ -and Ca2+-dependent ATPase (ATP phosphohydrolase, EC 3.6.1.3) of human prostatic fluid has been observed after the enzyme system had been inactivated by a detergent such as 0.05% deoxycholate. The concanavalin A effect was specific since the positive effect was abolished in the presence o alpha-methyl-D-mannoside. Furthermore, the positive effect of concanavalin A was obtained with a low lectin concentration, equal to the concentration reported for optimal stimulation of other membrane enzymes.

Adenosine Triphosphatases↗
PubMed1977

Malignant brain tumours associated with adenylate kinase in cerebrospinal fluid.

Adenylate-kinase activity was measured in cerebrospinal fluid (C.S.F.) from 35 healthy control subjects and 11 patients with brain tumours, of which 9 were malignant and 2 benign. No adenylate kinase could be detected in C.S.F. from the controls or from the patients with benign brain tumours. The enzyme was consistently found in C.S.F. from patients with malignant brain tumours.

Adenylate Kinase↗
PubMed1977

Prolonged succinylcholine-induced paralysis in connection with caesarean section. A case report.

A prolonged succinylcholine-induced paralysis was observed in connection with a casearean section in an otherwise healthy, 25-year-old female. Her serum pseudocholinesterase was analysed and found to be pathologically low, displaying in addition an atypical dibucaine number. Ten individuals related to her were also studied as regards pseudocholinesterase in serum. She had two brothers, one displaying the same pattern as herself, while the other had a normal pattern. Both of the parents had ordinary dibucaine numbers, while the father had a slightly decreased pseudocholinesterase activity. Possible mechanisms underlying the disorder are discussed.

Adult↗
PubMed1977

Preferential uptake of 14c-alpha-aminoisobuturic acid into mouse uterine tissue during early pregnancy.

The uptake of 14C-AIB into uterine tissue and some other organs was studied during early implantation. Mice in experimentally delayed implantation were given estrogen and 14C-AIB at different time intervals. Mice in delayed implantation given only 14C-AIB displayed a low transport rate into the uterine tissue, comparable with that for the diaphragm muscle. However, if the estrogen injection preceeded that of the 14C-AIB by 4 to 8 h the transport capacity increased by a factor of at least 4 times while the uptake for the diaphargm muscle remained low. Under such conditions 14C-AIB-accumulation into uterine tissue was favoured for at least 4 h of in vivo incubation with the labeled amino acid.

Aminoisobutyric Acids↗
PubMed1976

Alpha-aminoisobutyric acid transport into human glia and glioma cells in culture.

The AIB transport into human glia and glioma cells in culture has been studied. Because of the high affinity of AIB to the plastic culture dishes, a special washing technique had to be developed. With this technique, it was possible to perform transport experiments in a single plate containing about one million cells. The cells were viable, intact and adhered to the supporting medium throughout the experiment. The AIB transport into both types of cells was Na+-dependent and showed saturation kinetics when the small component of the transport due to diffusion had been subtracted. The AIB transport capacity of neoplastic glioma cells was 3.6 times higher than that of glia cells. This difference was related to the Vmax-values for the two types of cells. The apparent Km-values were the same. Inhibition experiments with other amino acids support the view that AIB is transported via System A in both glia and glioma cells. Sulfhydryl reagents (ethacrynic acid and NEM) and cytochalasin B clearly inhibited the AIB transport into glia cells whereas the effect on glioma cells was minimal.

Amino Acids↗
PubMed1976

Mg2+- and Ca2+-stimulated ATPase at the outer surface of human peripheral lymphocytes and hematopoietic cell lines. Correlation between enzyme activity and immunoglobulin secretion.

A Mg2+- and Ca2+-dependent ATPase at the outer surface of human peripheral lymphocytes and hematopoietic cell lines has been studied. The enzyme activity varied about 60 fold between the extremes of the cell lines tested. There was no simple relationship between surface-ATPase activity and cell surface area. Nor was the presence of villi or any other morphological characteristic at the cell surface decisive for the degree of surface-ATPase activity. A correlation was, however, found between the ATPase activity and a phenomenon probably involving a contractile process namely immunoglobulin secretion, but it was not possible to establish an interdependence of these cell characteristics.

Adenosine Triphosphatases↗
PubMed1976

Phosphorylation of endogenous membrane proteins by endogenous protein kinase at the outer surface of Ehrlich cells.

An endogenous protein kinase at the surface of Ehrlich cells has been studied. Using exogenous (gamma32P)ATP as a phosphoryl group donator, a transfer was demonstrated into endogenous acceptor protein(s) as well as to exogenous phosvitin. Seryl- and threonyl-residues isolated from the endogenous and exogenous acceptor protein were found to be labeled. The ratio between the labeled phosphorylserine and phosphorylthreonine was about 3.5:1 for both the endogenous acceptor of the intact cells and the exogenous acceptor. In similar experiments with a membrane preparation from Ehrlich cells, this ratio increased to about 7:1 provided the exogenous acceptor protein was absent. The results were independent of whether 1 X 10(-5) M dibutyryl cyclic AMP was used or not with intact cells and a membrane fraction mainly consisting of vesicles. Whether the regulatory subunit of the membrane-associated protein kinase was in cis- or trans-disposition to the catalytic subunit no binding and dependence of the cyclic nucleotide was observed. Since the purified membrane fraction was considered free from endogenous cyclic AMP, it was concluded that the membrane-associated protein kinase of Ehrlich cells is not dependent on cyclic AMP. The critical role of arginine for the cyclic AMP dependence of the serine-containing residue in the catalytic subunit is discussed.

Adenosine Monophosphate↗
PubMed1976

Serum adenylate kinase activity in the early phase of acute myocardial infarction.

Elevated adenylate kinase activities in serum and urine have been studied among patients suffering from myocardial infarction. 71% of the patients had clearly increased activities in serum already on admission to the hospital, i.e. about 12 hours after onset of symptoms and patients was 45%. A maximum peak value of the activity in serum was seen at 6 hours after admission to the hospital, i.e. about 12 hrs after onset of symptoms and the elevated enzyme activity value persisted for at least 12 hours after admission. The patients with the elevated adenylate kinase activity in serum were arbitrarily divided into three groups as regards activity. It was shown that the difference in activity of ASAT as well as LD of the high and low activity group was significant (p less than 0.01). No such difference was established between these groups for ALAT, usually not being considered as a reliable test enzyme for myocardial infarction.

Acute Disease↗
PubMed1975

On the availability of certain metabolites at the outer surface of normal and malignant cells for the membranous de novo synthesis of ATP and other nucleotides.

The formation of ATP at the cell surface of intact glia and glioma cells in culture has been established. The ATP-forming capacity at the surface of the malignant cells was several times greater than that of the normal glia cells. The ATP-forming capacity was about the same on reincubation one hour after the first incubation. The cells were kept in Eagle's medium in the meantime. ADP, NAD+ and 3-phosphoglyceraldehyde could all be available from a postulated intramembranous metabolic pool and take part in biochemical reactions at the cell surface, provided that albumin was not present in the incubation medium. An incubation medium which was complete except for 3-phosphoglyceraldehyde was only slightly less effective as regards ATP formation at the surface of both glia and glioma cells, compared with the complete incubation medium. The presence of nucleoside diphosphate kinase at the glioma cell surface was confirmed. When intact cells were incubated with only the phosphoryl group donor (ATP) of the reaction but with the acceptor nucleoside diphosphates (CDP, GDP, UDP) ommitted, only CTP and GTP were formed. No UTP was found. Thes latter results indicate that both CDP and GDP are available from the postulated intramembranous metabolic pool, while UDP is not.

Adenosine Triphosphate↗