Regional Distribution of Lithium Following Intravenous Injection and Its Effects on Plasma and Urine Electrolytes

This study was carried out to investigate the early regional distribution of administered litbium and the effects of lithium-load on the plasma concentration and urinary excretion of Na" and K+. After single intravenous injection of LiC! solution (l. :;rnEq/kg), :;,1:;,30 and 60 min. samples were taken from carotid artery, renal vein, jugular vein, femoral vein and urinary bladder. Na", K+ and LiT concentrations were measured together with the determination of creatinine and osmolarity. From these values several clearance data were calculated. The following results were obtained: 1. Arterial Li" concentration measured at 5,15,30 and 60 min. after injection were 7. 9±0. 77, 6.2± 0.52, 4. 8±0. 46 and 3. 5±0. 40mEq/1 respectively. Regional venous Li" concentrations decreased similarly as time went by. 2. Arterio-venous Li" concentration differences in jugular vein were -0. 4±0. 98, O.2±0. 45, -0.2± 0.16 and 0.1±0. 29 rnEq/l at 5,15,30 and 60 min. respectively. So there was no arteria-venous differences in jugular vein. 3. At 5 min., there was a significant difference of 2. 8±0. 43mEq/1 between arterial and venous Li" concentration in femoral vein. But the differences became smaller as time progressed and no significant difference was noted by 60 min. 4. Li" concentrations of renal venous blood were always significantly higher than those of arterial blood. 5. In both control and Li group plasma Na" concentrations decreased gradually as time went by. But there was no significant differences between the groups. 6. Plasma K+ concentration increased gradually with the time lapse in both groups, but there was no significant differences between control and Li group. 7. In control group. urine volume decreased from the control value, O. 066±0. 026 nil/min/kg, progressively to O. 031±0. 014 ml/min/kg by 30 min. On the contrary, in Li group urine volume increased from the control value, O. 066±0. 014 ml/rnin.ykg to o, 186±0. 020, O. 086±0. 020 and O. 043±0. 006 ml/ min/kg at 5,15 and 30 min respectively. 8. Free water clearance were reversed from control negative value to positive at 5 min. in both groups but the increment was greater in Li group. 9. Li" clearances at 5, 15,30 min. were 0.64, 0.36, 0.10 ml/min/kg, respectively. From the above results, it was concluded that the administered Li" were distributed to all the body tissue except brain. Also concluded that Li" were filtered at glomerulus and reabsorbed at renal tubules resulting the inhibition of electrogenic Na" reabsorption initially and then followed by inhibition of water reabsorption by chemical mechanism

Potassium Transfer in Metabolic Acidosis of Various Origins

Mechanisms of the potassium transfer in metabolic acidosis of various origins were studied in the rabbit skeletal mt엽cles. Metabolic acidosis was induced by infusion of either O. 3M hydrochloric acid, O. 6M lactic acid or 0.3M potassium chloride solutions. Intracellular pH (pH;) was measured by means of 5, 5-dimethyl-2, 4-oxazolidinedione (DMO) distribu' tion πethod. And simultaneously plasma pH and intra- and extracellular potassium ion concentrations were measured. The results obtained were as follows: 1. The normal arterial pH (pH.) was 7.39 and intracellular pH of the skeletal thuscle was 7.00. 2. In HCI and lactic acid group, pH. decreased to 7.01 and 7.03 , and pH; to 6.65 and 6.75 , respectively. Whereas in KCI group the pH. decreased t。 only 7. 11 and pH; did not decrease significantly from the control value 3. In HCI group the plasma K concentrations increased from the control value of 3. 8±0. 3 to 7.2 ±1. OmEq/1 along with the lowering of the pH•. In lactic acid group , on the other hand, the plasma K concentration did not change while the pH. remained in the range of 7.1~7. 4. However, when pH. fell lower than 7. 1 plasma K concentration increased gradually. The normal intracellular K concentration, 158±4, 159±3mEq/I, decreased to 145士5 and 154± 5 mEq/1 in HCI and lactic acid group, respectively. 4. The ratio of H;/H, decreased in order of KCI, lactic acid and HCI group, while K;/K , decreased in order of KCI, HCI and lactic acid group. Above results suggested that the mechanisms of the K transfer across the cell membrane in HCI and lactic acid groups might be different. The small but definite increment in plasma K ion concentration in lactic acidosis implied that K-H exchange mechanism might be involved partially in H transfer across the cell membranes

Acid-Base Changes of Acute Hypoxic Respiratory acidosis in Rabbits

Experimental acute respiratory acidosis is mostly induced by raising simply arterial carbon dioxide tension , clinical respiratory acidosis , however. is usually complicated with hypoxia. To induce hypoxic respiratory acidosis. rabbits were introduced to air tight chamber for few hours to 21 hours Acid·Base data analyzed were as follows: 1. Breathing in the small chamber, environmental air P02 decreased and PC02 increased steadily. Arterial blood Pco, increased along with the environmental air Pco.. although arterial blood Po, did not always decrease with the environmental PO~. Defense against to the hypoxia in the moderate degree of air Po, depression was achieved by the hyperventilation 2. Up to the moderate degree of Po, depression , hypoxic hypercapnia were not different from hypercapnia without hypoxia, however , the lower the Po, the more to be combined with metabolic acidosis. two out of seven respiratory acidosis were not combined with metabolic acidosis at all. 3. Plasma potassium concentration were always elevated whether it is hypoxic , or combined with metabolic acidosis. The increment was more when acidosis is severe and elapsed longer with acidosi

Effect of Extracellular pH on Contracture in Frog Ventricle

Potassium contractures were induced in isolated frog(Rana tcmporaria) ventricular strips with trisbuffered Ringer solutions containing 20~100mM K ions and concomitantly less Na ions at room temperaturet lS to 20nC). External pH was raised up to 8.4 or lowered down to 6.4 and its effect upon K-contracture was investigated to elicit the mechanism of action of H ions on excitation-contraction coupling in frog ventricular myocardium. Followings are the results obtained: ]. At normal pH, biphasic contracture was evoked at external K concentration of 40mM. On rasing K concentration to lOOmM, contracture tension increased gradually and the interval between the end of contracture and resuming of twitch was also prolonged. When K-20mM solution was replaced by normal Ringer solution, twitch tension developed rapidly and much higher tension than control twitch was elicited transiently. After the first application of K-100mM fully recovered tensions were always smaller than those of control twitch tensions. 2. On raising external pH from normal to 8.4, there were no significant changes in K-induced contractures comparing to those evoked under normal pH. 3. On lowering external pH down to 7.4, phasic portion of K-contractures were augmented within the range of 20 to 40mM K and tonic portions in creased gradually with time elapsed at 100mM K ion concentrations. From the above results it was concluded that H ion acted upon contracture induced by high K with low Na ion" Via the inhibition of Na-K pump during the early phase and changes in intracellular pII during the later phase

Attitude of Student to the Postgraduate Education in Medical Field

The attitudes of the medical graduate students to the postgraduate education were surveyed for 145 randomly sampled students who are taking courses in 3 medical graduate schools. The questionaire was composed of 10 items which were dcvidcd under three heads. namely, to improve current educational system, to improve the operational efficiency and to strengthen the supporting measures. Although the survey was not an extensive one, the responses revealed following views: 1. The motives for the advanced studies were not necessarily originated from the academic ground. 2. There are two different postgraduate courses in this country, namely the training course for the clinical specialty and the advanced academic course in the graduate school of the university, leading to the higher degrees. Many of medical graduates arc taking two courses at the same time and it results in a tremendous difficulty especially in the degree course because of their heavy duty in the clinical discipline. 3. A combined course is desirable instead of two separated courses in the postgraduate educational system. 4. That combined course will be a professional degree course which will be offered to the clinical field and it will concern with the professional competence as well as the academic capability. Part of the course well be covered by the research activities in the basic science departments or some research institutes. 5. Sometimes tbe freedom of academic activity has been restricted by the domination of the advisor's choice. 6. Pass or fail system is more desirable than any other evaluation systems for their performance. 7. There are widespread dissatisfaction for the library and research facilities and the complaint for the latter is louder than for the former

Effects of ADH on renal handling of lithium and lithium induced diuresis in rabbits

The effect of ADH on renal handling of lithium .and lithium induced diuresis was investigated in rabbits pretreated with lithium (control group) or lithium and ADH (ADH group). LiCI (lmEq/kg) was administered intraperitoneally for 3 days and ADH (0.5ii/kg) was injected intramuscularly on the 2nd and 3rd days in ADH group. On the 4th day morning single intravenous injection ,of LiCI (2mEq/kg) was given. After then 10, 30 and 60 minute samples were taken from carotid artery and urinary bladder. Urinary flow rate, Na", K+, Li" and osmolarity were measured together with .the plasma concentration of them. Followings are the results obtained: 1. Before single injection of large dose of LiCI, plasma concentration and urinary excretion rate of Li" were lower in ADH group than in control group. On the other hand, urine volume, osmolarity and .excretion rate of Na" were higher in ADH group than in control group. 2. Plasma concentration and urinary excretion of K+ were lower in ADH group and particularly urin. ary excretion decreased markedly after single injection of large dose of LiCI. 3. After single large dose injection of LiCI plasma Li" concentration decayed more rapidly in ADH .group, On the contrary, urinary excretion decreased slightly. 4. There were no significant differences in Li-in- duced water diuretic and natriuretic response between both groups. From the above results we conclude that administration of ADH stimulates water and natriuresis in rabbits induced by a small dose of LiCI but has no effect upon diuretic responses induced by a large dose of LiCl, and also ADH stimulates accumulation of lithium in tissues especially in renal medulla

Effects of Manganese Ion on the Action Potential and Contractility of Frog Atrial Muscle

The effect of manganese ion on transmembrane potential and tension of the atrial strip was studied in the frog. Manganese (l~8 mM) suppressed the plateau resulting in a shortening of action potential duration. The change was a function of time and during the first 5 minutes the action potential duration increased, then it gradually shortened. Although resting membrane was more or less hyperpolarized, there was no significant changes in the amplitnde of action potential and resulted in an increased overshoot potential. In all the experiments the contractile tension of atrial muscle superfused with Mn-Ringer decreased consistently as the concentration of manganese increased. But 10 to 20% of relative tension to that of control persisted even at 8 mM Mn-Ringer for more than half an hour. Manganese elevated the threshold of atrial contraction and reduced the conduction velocity. The above results suggested that manganese not only altered the transmembrane potential but also acted on the excitation-contraction coupling to produce a decrease in tension