Biomedical subjects

G Ronquist

Publications and source records attributed to G Ronquist.

276 records · Page 16Linked to original sources

PubMedDate not supplied

Motility stimulant effects of prostasome inclusion in swim-up medium on cryopreserved human spermatozoa.

The chance of obtaining a fertilization and establishing a pregnancy increases with the number of motile spermatozoa that can reach and interact with the oocyte after the time of insemination. In an attempt to increase the recovery of freeze-thawed and motile spermatozoa, the swim-up medium was supplemented with prostasomes and some other effectors. Swim-up media supplemented with prostasomes were superior in comparison to the other effectors investigated in the recovery of motile spermatozoa for insemination. These results suggest that prostasome inclusion in swim-up medium might be of benefit in improving results in assisted reproductive technologies using freeze-thawed spermatozoa.

Aminopeptidases↗

PubMedDate not supplied

Analysis of ejaculates from patients with cystic fibrosis.

Ejaculates from two men with cystic fibrosis (CF) were examined. Both had azoospermia. A considerable decrease in volume and fructose content was noted. The absolute amounts of calcium, magnesium, and zinc per ejaculate showed normal values in one of the patients but were two to three times increased the the other compared to mean values of a control group. Thus the concentrations of these cations were increased at least fivefold in both patients. The amount of Mg(2+)-and Ca(+)-dependent ATPase was comparable to that of controls, but values were higher than in men with oligospermia. Both the divalent cations and the Mg2+- and Ca2+-dependent ATPase curve profiles of split ejaculate fractions were atypical. Secretory granules and vesicles were plentiful in the seminal plasma of both patients while amorphous substance was practically absent. The present findings agree with a less affected function of the prostate gland and a dysfunction of the seminal vesicles in these patients.

Adenosine Triphosphatases↗

PubMedDate not supplied

Rabbit spermatozoa: a model system for studying ATP homeostasis and motility.

This paper studies the adenosine triphosphate (ATP) homeostasis and the motility parameters of rabbit spermatozoa. Rabbit sperm, collected by artificial vagina, were studied in various buffer systems to determine motility over time. Sperms were also extracted to measure enzyme activity. Analyses of motility by Computer Assisted Semen Analyzer system were run in parallel with energy metabolic studies of sperm cells maintained in different physiological solutions sometimes containing inhibitors of energy metabolism. Rabbit spermatozoa were shown to be able to form ATP either via glycolysis or via oxidative phosphorylation. Both these metabolic pathways were active in viable cells where creatine kinase and adenylate kinase systems were also present (1.1 and 7,000 nmol/min per 100 x 10(6), respectively) and involved in maintaining high ATP levels. A dynamic balance between ATP synthesis and ATP-hydrolyzing enzymes was suggested by the fact that rabbit sperms in their seminal plasma preserved their motility for hours. The decrease in sperm ATP content was mainly due to its hydrolysis by dynein ATPases coupled with movements. Therefore, motility of rabbit spermatozoa appeared to be dependent only on the ATP available to dynein ATPases. In fact, statistical analyses of motility parameters and the concentrations of intracellular ATP or ATP-metabolite did not show any significant correlation.

Adenosine Triphosphate↗

PubMedDate not supplied

Antitumour effect of L-2,4 diaminobutyric acid on a hepatoma cell line.

Pharmacological treatment of malignant disease is often insufficient highlighting the need for more efficient treatment based on new principles. We have observed that the amino acid analogue diaminobutyric acid (DAB), accumulates in malignant cells apparently without saturation kinetics, leading to hyperosmosis and subsequently to cell lysis. In the first in vitro part of the present study hepatoma cells were incubated with DAB in miniwells in the presence or absence of physiological amino acids. In the in vivo part malignant cells were inoculated into rat liver after laparotomy. The tumour was treated by continuous infusion of DAB via a catheter, the tip of which was placed in the center of the tumour. DAB had a significant antitumour effect both in vitro and in vivo. The principle of action of DAB as an antitumour agent is unique and therefore would be the ideal partner to practically any other cytostatic drug for a combined treatment to achieve a synergistic effect.

Aminobutyrates↗

PubMedDate not supplied

Prostasomes in human semen contain ADP and GDP.

Prostasomes from human semen contained ADP and GDP (mean values 81 +/- 58 respective 71 +/- 46 nmoles/g protein; n = 20) while other nucleoside phosphates were not detected as determined by high performance liquid chromatography. A strong linear relationship (r = 0.80, p less than 0.001) existed between ADP and GDP in prostasomes, while ADP (but not GDP) correlated inversely with semen volume (r = 0.54, p less than 10.02). The possibility is discussed of ADP and GDP being incapsulated within the prostasomes as a macromolecular complex involving stacked nucleotides held together by divalent cations through the phosphate groups.

Adenosine Diphosphate↗

PubMedDate not supplied

Induction of complete and irreversible damage to malignant glioma cells by L-2,4 diaminobutyric acid.

L-2,4 Diaminobutyric acid (DAB), a non-physiological amino acid, induced an irreversible injury to human malignant glioma cells when incubated for 24h at an amino acid concentration of 6 mmol/l at 37 degrees C. The same treatment of the human glia cells did not result in any cellular damage; not even a concentration as high as 20 mmol/l of the amino acid under the same incubation conditions did affect these cells. However, a further increase in amino acid concentration above that level resulted in a gradual loss of viability among the human glia cells. An experimentally induced rat glioma cell line was also affected by DAB, although displaying less sensitivity than the human glioma cells, and complete cellular destruction was achieved at 16 mmol/l of DAB, i.e. well below the critical concentration for human glia cells. The destructive effect by DAB was pH-sensitive. The N-methylated analogue of a - amino-isobutyric acid exerted a specific inhibitory action on DAB activity, but other amino acids were also inhibitory to various degrees at higher concentrations. Future clinical applications in the treatment of malignant brain tumours in man are discussed.

Aminobutyrates↗