Biomedical subjects

H D Kim

Publications and source records attributed to H D Kim.

At least 163 records · Page 9Linked to original sources

PubMed1976

Transitory postnatal hemolysis of calf red cells by amino acids.

Among the amino acids which can be solubilized to give a concentration of 300 mm at near physiological pH, histidine and proline caused a complete hemolysis of newborn calf but not of adult cow red cells within 20 to 30 minutes at 38 degrees C. While hydroxyproline, valine, and serine resulted in a partial lysis of calf cells, threonine, glutamine, and glycine were ineffective. In this communication, emphasis has been focused on the mode of the lytic process by histidine which was found to be affected by several governing parameters including the pH, temperature and the extracellular salts in the solution. Unlike human red cells suspended in isotonic histidine, both calf and cow cells lost little Na and K ions. In the presence of 300 mm histidine, both calf and cow cells displayed an instantaneous uptake of histidine amounting to 20 to 45 mumoles/ml RBC followed by a slow influx rate of 0.25 to 0.5 mumoles/ml RBC X min. The extent to which histidine entry was allowed by the cell was counterbalanced by Cl- efflux, resulting in little change in cell volume prior to hemolysis. Moreover, histidine-induced hemolysis can be prevented by 1 mm or lower PCMBS without a discernible effect on histidine influx suggesting a possible membrane lesion or damage at the outer surface of the cell. Hemolysis induced by histidine decreased substantially when a calf reached two months of age at which time the red cells containing the fetal hemoglobin are virtually depleted. The results of hemoglobin electrophoresis obtained during this postnatal period revealed that those cells resistant to histidine hemolysis almost invariably contain the adult type hemoglobin suggesting a selective, specific action of the amino acids on the fetal cells.

4-Chloromercuribenzenesulfonate↗

PubMed1976

Observations on the (Ca2+ plus Mg2+)-ATPase activator found in various mammalian erythrocytes.

1. A soluble activator of membrane (Ca2+ plus Mg2)-ATPase is present in hemolysates of the newborn calf and cow, the new born and adult pig as well as human erythrocytes. 2. The activator is also found in reticulocytes of the adult pig. 3. The activator obtained from any of the above species is capable of stimulating the membrane (Ca2+ plus Mg2+)-ATPases of the other species, regardless of the age of the animals. 4. The results obtained from density fractionation of human erythrocytes revealed that the soluble factor has little simulatory effect on membranes of young erythrocytes from which it is derived but caused a marked stimulation on (Ca2+ plus Mg2+)-ATPase activity of the intermediate aged and old erythrocyte membranes. 5. The above observations support the following conclusions: (a) the extremely low levels of (Ca2+ plus Mg2+)-ATPase in cow erythrocytes is not due to the lack of a (Ca2+ plus Mg2+)-ATPase activator; (b) the distribution of (Ca2+ plus Mg2+)-atpase activator is not species specific and the differences in the level of membrane (Ca2+ plus Mg2+)-ATPase activity in various species of cells is an inherent property of that particular membrane (c) the (Ca2+ plus Mg2+)-ATPase activator is present at least from the time of reticulocyte formation and remain during tthe life span of the erythrocyte.

Adenosine Triphosphatases↗

PubMed1976

Kinetics of 3-O-methyl glucose transport in red blood cells of newborn pigs.

The glucose-permeable fetal red cells in the pig are entirely replaced by glucose-impermeable adult red cells within a month after birth. This study investigates the kinetic parameters of the glucose transport mechanism in newborn pig red cells in comparison with immature adult red cells (reticulocytes) as well as the fully matured adult erythrocytes. Influx and efflux of the nonmetabolizable 3-O-methyl glucose (3-O-M-G) in red cells of newborn pigs saturate at high substrate concentrations and exhibit typical Michaelis-Menten kinetics. Km values for efflux are 15.2 and 18.2 mM for 15 and 22 degrees C, respectively. Q10 computed between 10 and 26 degrees is 5.0. The energy of activation for the transport process is 34,000 cal mol-1. The effectiveness of hexoses in competing with 3-O-M-G in efflux is in the following order: D-glucose greater than D-mannose greater than D-fructose greater than D-galactose. Efflux of 3-O-M-G does not increase with 3-O-M-G or D-ribose in the medium and is reduced by 2,4-dinitroflurobenzene (DNFB), p-chloromercuriphenyl sufonic acid (PCMBS), and phloridzin. The reticulocytes are shown to possess a carrier-mediated transport but with a considerably lower transport rate. As the reticulocytes mature into normal red cells, the carrier transport mechanism is lost.

4-Chloromercuribenzenesulfonate↗

PubMed1976

Pig reticulocytes: I. Transitory glucose permeability and metabolism.

Glucose permeability and metabolism were examined in the reticulocytes of pigs made anemic by daily administration of phenylhydrazine for 5-7 days. Blood samples containing 70-90% reticulocytes were fractionated according to their density by centrifugation. The most immature reticulocytes obtained from the top centrifugal fractions possessed a glucose permeation mechanism. The salient features of glucose transport include a) saturable kinetics with Vm ranging from 0.1 to 0.4 mumol/ml cell X min and with Km ranging from 6.6 to 12 mM, b) inhibition by phloretin, and c) countertransport characteristics suggesting that the glucose entry was mediated by a mechanism involving membrane carrier-type transport. In the course of reticulocyte maturation leading to mature red cells, the glucose carrier mechanism was discarded or rendered ineffective, resulting in nonglycolytic mature red cells. Glucose and ribose consumptions in the most immature reticulocytes were 2.5 and 0.75 mumol/ml cell X h, respectively. Concomitant with the diminishing glycolytic ability, ribose consumption was enhanced slightly as the reticulocytes matured to red cells. Dihydroxyacetone, a potent metabolic substrate for the mature pig red cell, was utilized readily by the reticulocytes.

4-Chloromercuribenzenesulfonate↗

PubMed1976

Pig reticulocytes: II. Characterization of density-fractionated maturing reticulocytes.

A simple centrifugation technique initially developed for fractionation of human red cells in their own plasma has been found to be readily applicable to the separation of reticulocytes normally appearing in the pig soon after birth as well as to those induced in the adult pig by phenylhydrazine administration. The density of the naturally occurring reticulocytes, maximally amounting to 10-15% of total cells derived from a 7-day-old pig, varied from 1.073 to 1.101, in contrast to the mature cells, presumed to be the fetal cell type, whose density ranged in a narrower limit, from 1.101 to 1.106. In adult animals, the reticulocytosis amounting to more than 70% takes place in response to daily administration of phenylhydrazine for 7 days. The density of these reticulocytes varied widely from 1.068 to 1.094; in contrast, the density of the mature adult red cells ranged from 1.095 to 1.106. Among various physiological parameters examined, a marked decrease in cell size, cell water content, RNA, Na+ -K+ -ATPase, and Ca2+ -ATPase activities was observed in the course of reticulocyte maturation in vivo in the adult animal. All these physiological parameters were found to undergo a similar reduction from the top to the bottom fractions of the reticulocytes separated according to their density, suggesting that the separation technique employed here represents separation of reticulocytes according to their age.

Acetylcholinesterase↗

PubMed1975

Effects of Tris and histidine on human erythrocytes and conditions influencing their mode of action.

1. The incubation of human erythrocytes in 0.172 M Tris - HCl, pH 7.6 buffer at 37 degrees leads to (1) a pronounced cellular volume increase, (2) a preferential release of Na+, and (3) if continued sufficiently long, hemolysis. These effects are pH dependent and also are influenced to a considerable degree by such diverse reagents as NaC glucose, and histidine. In each instance, increasing levels of the latter compounds in a Tris - HCl incubation mixture led to diminished cellular volume increase and prolonged time of onset of hemolysis. 2. Histidine solutions of 0.31 M, pH 7.5 caused a rapid and dramatic decrease in cellular volume of human erythrocytes and a concomitant rapid exit of cations. However, in a prolonged incubation, human erythrocytes slowly regained their cell volume as a result of histidine entry into the cell. Of considerable interest: Tris swollen cells undergo immediate shrinkage to far below the initial cell volume when incubated in histidine at 37 degrees C. Through repetition of this process two additional times, as much as 90-95% of the total cellular Na+ and K+ was removed without hemolysis. 3. Human erythrocytes washed in 0.12 M MgCl2 and then suspended in 0.31 M histidine, pH 7.5, lost upwards of 60% of their total Na+ and 30% of their total K+ after a 40 min incubation at 37 degrees C. However, when increasing amounts of 0.172 M Tris - HCl, pH 7.6 were added to the histidine suspension of cells, the release of K+ was reduced to 5% but the release of Na+ decreased only to 40% of the total cellular level. On the basis of these observations, it is evident that Tris exerts a preferential activity towards the efflux of Na+ from the human erythrocyte, whereas histidine results in high efflux of K+ and Na+ from the cell.

Animals↗

PubMed1974