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The correlation between Creatinine concentration, osmolality and blank color of urines was investigated. Only values of creatinine concentration and osmolality allow an approximative inter-conversion. For urine analysis, especially in cases of a very high creatinine concentration, we recommend to measure osmolality as a control.
The range of activity of subminimal inhibitory concentrations of some beta-lactam and aminoglycoside antibiotics against both gram-negative and gram-positive bacteria was determined and expressed as the ratio of the minimal inhibitory concentration (MIC) to the minimal antibiotic concentration (MAC). Ten strains of Staphylococcus aureus were tested with ampicillin, cefamandole, and cefoxitin. The mean MIC/MAC ratios were 9.4, 14.0, and 2.9, respectively. The mean MIC/MAC ratios for 10 strains of Escherichia coli that were tested with the same three antibiotics were 20.6, 25.2, and 15.1, respectively. The same strains of E. coli and S. aureus were tested with amikacin, gentamicin, and tobramycin. The respective mean MIC/MAC ratios were 13.1, 6.2, and 7.4 for E. coli and 3.7, 5.1, and 3.1 for S. aureus. Ten strains of Serratia marcescens were tested with amikacin, chloramphenicol, and these two drugs combined. The mean MIC/MAC ratios for amikacin and chloramphenicol were 6.8 and 2.1, respectively. For the combination, the mean MIC/MAC ratio was 9.2, a finding that indicates synergism. Determinations of MIC/MAC ratios could provide valuable information for the monitoring of antibacterial therapy, especially when drugs of significant toxicity are used.
Measurement of plasma renin concentration (PRC) was done in normal subjects at rest and under acute stimulation of renin release under unrestricted sodium intake. Concurrent measurements of plasma renin activity (PRA) and plasma aldosterone concentration (PA) were carried out. The mean values of PRC at rest and after stimulation of renin release were 12.8 +/- 1.3 (SEM) and 21.7 +/- 4.4 (SEM) ng AT I/ml/h, respectively. These corresponded to renin contents of 3.4 +/- 0.34 (SEM) X 10(-5) Goldblatt units and 5.8 +/- 0.36 (SEM) respectively. The mean percent increase of PRC (82.1 +/- 19.3 (SEM)) %) was almost indentical to that of PA (81.5 +/- 16.4 (SEM) %), but differed from that of PRA (269 +/- 83.1 (SEM) %). A very high correlation between concurrent PRC and PA (r = 0.92, P less than 0.001) was found in normal subjects at rest and under acute stimulation of renin release. A good correlation between PRC and PRA (r = 0.85, P less than 0.001) was also observed. However, a higher correlation between percent increases of PRC and PA (r = 0.92, P less than 0.001) than that of PRA and PA (r = 0.80, 0.01 less than P less than 0.005) was found. Results show that PRA is a good index of the renin content in plasma in normal subjects at rest and PRC reflects actual renin concentration in plasma at rest as well as under stimulation of renin release.
Testosterone (T) and estradiol (E2) concentrations were determined and correlated with beta human chorionic gonadotropin (beta-HCG) concentrations in 43 paired maternal and cord sera (22 female and 21 male infants). Mean (+/- SD) maternal E2 concentrations were significantly (P less than .005) higher when the sex of the fetus was male than when the sex of the fetus was female (20.6 +/- 3.9 vs 13.5 +/- 3.2 ng/ml). Maternal T concentrations were not significantly different when related to the sex of the fetus (males, 114.8 +/- 60.7 vs females, 113.8 +/- 54.5 ng/100 ml, P greater than .1). Regression analysis did not show a significant correlation between maternal T or E2 concentrations and maternal beta-HCG concentrations. Mean cord serum T and E2 concentrations of male infants were significantly greater than that of female infants (T, 38.8 +/- 8.5 vs 25.8 +/- 7.1 ng/100 ml, P less than .005; E2, 9.1 +/- 3.3 vs 6.6 +/- 2.0 ng/ml, P less than .005). Regression analysis showed a significant (P less than .005) correlation between cord beta-HCG concentrations and E2 concentrations for male infants (r = .7) and female infants (r = .6). A significant correlation between cord beta-HCG concentrations and T concentrations was found for male infants (r = .5; P less than .01) but not for female infants (r = .3; P greater than .05). There was no correlation between maternal and infant E2 concentrations (males, r = .3, P greater than .05; females, r = .3, P greater than .2) or T concentrations (males, r = .02, P greater than 0.4; females, r = .06, P greater than .3). These data (1) confirm the sex difference in cord serum T and E2 concentrations, (2) indicate that the lower beta-HCG concentrations in mothers of male infants are associated with E2 concentrations which are greater than those in mothers of female infants, and (3) are consistent with an influence of beta-HCG on fetal T and E2 secretion.
The measurements were made of the unidirectional potassium fluxes, the rate constants and the permeability coefficient. At external potassium 2.5 mM, the outflux and influx are 10--15, and 22-29 micromol/h g d. wt, respectively, and the net flux is comparable with the unidirectional fluxes. At external potassium 75 mM, the unidirectional fluxes increase up to 70--80 micromol/h, g d. wt. and the net flux does not exceed 0.1 of the unidirectional one. The outflux rate constant/influx rate constant ratio for both the potassium concentrations is about 1.5 times below the Ussing's ratio. This effect cannot be accounted for the single file phenomenon since it is independent of the direction and value of the net potassium flux. The discrepancy between the measured membrane potential and EK may, to some extent, be due to peculiarities of potassium movement.
Plasma fluoride, urine fluoride and urine oxalate concentrations were measured before administering an anesthetic to 8 dogs, and at 0, 3, 9, 24, 48, and 72 hours following 1.5 hours of anesthesia with 1% methoxyflurane. Plasma and urine osmolalities were measured and compared with fluoride and oxalate values. Fluoride concentration increased in both plasma and urine following anesthesia when compared with the preanesthetic concentrations. Maximum mean plasma inorganic fluoride was 106.71 mumoles per liter (+/- 25.44 SE) at 9 hours after exposure to methoxyflurane was completed. By 72 hours after exposure to methoxyflurane the plasma fluoride concentration was 23.47 microM/L (+/- 5.74 SE). Mean urine inorganic fluoride concentration was highest at 9 hours after exposure to methoxyflurane and reached 6047.03 microM/L (+/- 1378.46 SE) as compared to the mean preanesthetic base-line concentration of 542.68 microM/L (+/- 132.93 SE), and the 72 hour mean urine fluoride concentration which was 1593.78 microM/L (+/- 579.46 SE). Urine oxalate concentrations, when compared with urine osmolality (mg/mOsm), increased throughout the study. The 72-hour concentration after exposure to methoxyflurane was 2.5 times the preanesthetic (mg/mOsm) oxalate concentration. Plasma osmolality did not change markedly during the study. Urine osmolalities varied between animals and collection times, but a consistent pattern did not occur. Clinical and laboratory signs of renal dysfunction were not observed in any animal during the study.
Effects of glucose concentration and anoxia upon the metabolite concentrations and rates of glycolysis and respiration have been investigated in the perfused liver of the fetal guinea pig. In most cases the metabolite concentrations in the perfused liver were similar to those observed in vivo. Between 50 days and term there was a fall in the respiratory rate and in the concentration of ATP and fructose 1,6-diphosphate and an increase in the concentration of glutamate, glycogen and glucose. Reducing the medium glucose concentration from 10 mM to 1 mM or 0.1 mM depressed lactate production and the concentration of most of the phosphorylated intermediates (except 6-phosphogluconate) in the liver of the 50-day fetus. This indicates a fall in glycolytic rate which is not in accord with the known kinetic properties of hexokinase in the fetal liver. Anoxia increased lactate production by, and the concentrations of, the hexose phosphates ADP and AMP in the 50-day to term fetal liver, while the concentration of ribulose 5-phosphate, ATP and some triose phosphates fell. These results are consistent with an activation of glycolysis, particularly at phosphofructokinase and of a reduction in pentose phosphate pathway activity, particularly at 6-phosphogluconate dehydrogenase. The calculated cytosolic NAD+/NADH ratio for the perfused liver was similar to that measured in vivo and evidence is presented to suggest that the dihydroxyacetone phosphate/glycerol 3-phosphate ratio gives a better indication of cytosolic redox than the lactate/pyruvate ratio. The present observations indicate that phosphofructokinase hexokinase and possibly pyruvate kinase control the glycolytic rate and that glyceraldehyde-3-phosphate dehydrogenase is at equilibrium in the perfused liver of the fetal guinea pig.
Slightly halophilic marine Vibrio alginolyticus grown in the range of NaCl from 0.2 to 1.5 M maintained the total internal solute concentration always higher than the external medium by about 0.25 osM. The concentrations of macromolecules such as DNA, RNA, and protein were little affected by the increase in medium NaCl. The internal K+ concentration was kept to about 400 mM in the range of medium NaCl from 0.4 to 0.8 M; it rose to 510 mM when the bacterium was grown in 1.5 M NaCl, indicating that K+ increased only slightly in response to the large increase in medium NaCl. Thus, in contrast to the case of nonhalophilic and extremely halophilic bacteria, K+ was unlikely to act as a major component to regulate the internal solute concentration of marine V. alginolyticus. The internal Na+ and Cl- concentrations were maintained always lower than those in the growth medium, but they increased in response to the increase in medium NaCl. The concentration of internal Na+ was close to that of K+ at the concentration of medium NaCl that supports the optimal growth of this organism. The total amino acid content of V. alginolyticus increased from 76 to 413 mM by the increase in medium NaCl from 0.2 to 1.5 M. The concentrations of glutamic acid and prolined were 254 and 72 mM, respectively, when grown in 1.5 M NaCl. These results indicated that Na+, Cl- and amino acids, especially glutamic acid and proline, contributed to the regulation of internal solute concentration of V. alginolyticus in response to the increased external NaCl.
Amylase concentration, L/S ratio and lecithin concentration were measured in 110 samples of amniotic fluid in 106 uneventful pregnancies. Amylase concentrations lower than 200 U/l corresponded significantly (p less than 0.001) to a gestational age less than the 37th week as well as to a L/S ratio lower than 2 and to lecithin concentrations lower than 3.5 mg%. Furthermore, amylase values higher than 300 U/l corresponded significantly (p less than 0.001) to a gestational age over the 37th week as to an L/S ratio over 2 and to lecithin concentrations over 3.5 mg%. On the other hand amylase concentrations ranging between 200 and 300 U/l failed to show any significant relationship neither to the age of gestation nor to the concentration of phospholipids. These findings show that the amylase test is a useful method for prediction of fetal maturity. Since the procedure of determination of the amylase concentration is very simple, cheap and rapid, the test can be used as screening method. However, when amylase concentrations are found to range between 200 and 300 U/l specific tests for assessment of fetal maturity have to be applied.
The primary causative factor in abomasal displacement appears to be atony or hypotony of the abomasum. Seemingly, high-concentrate feeding inhibits abomasal motility by increasing the amount of fatty acids which enter the abomasum. In the present study, cows with ruminal, abomasal, and duodenal fistulas were fed a hay ad libitum ration or a hay and concentration ration and were compared. It was shown that a considerable increase in ruminal volatile free fatty acid (VFFA) concentrations was not followed by a subsequent increase in abomasal VFFA concentrations. Differences in abomasal VFFA levels between the 2 rations could not be found. There was a slight, but insignificant, increase in duodenal VFFA concentrations after cows were fed the hay ration. One cow given the hay and concentrate diet had a small, but significant, increase in duodenal VFFA concentrations during the first 2 hours after feeding. The VFFA concentrations in duodenal fluid were too low to support the hypothesis that changes in duodenal VFFA concentrations could be responsible for abomasal hypotony.
17 beta-Estradiol (E2) and progesterone (P) concentrations in blood and in the myometrium of human pregnancy at term (n=33) and in a few samples (n=5) around midterm of pregnancy were determined. E2 concentration in the myometrium (per g wet wt) at midterm was lower than the concentration in the plasma (per ml) so that the myometrium to plasma (My:Pl) ratio was 0.7. Relative to plasma concentration, the myometrial E2 increased little from midterm to term so that My:Pl was only 0.2 at term. Although P concentration in the myometrium was much greater than that in the plasma at midterm, My:Pl ratio being 2.2, it was lower than that in plasma at term so that My:Pl ratio was only 0.6. A fairly good correlation between plasma steroids and the myometrial steroids was observed at midterm but was distorted at term, probably due to saturation of the tissue-binding capacity. Steroid concentrations determined on the basis of protein showed a good correlation to the values expressed on the basis of wet weight. Whereas myometrial E2 concentration was significantly influenced by the distance from placenta, P concentration was not.
Heat stability as a function of pH has been studied in concentrated and non-concentrated milk systems. The influence of preheating has also been examined. The concentration of beta-lactoglobulin has been shown to affect markedly the heat stability behaviour in both systems but with different characteristics. Increasing the level of urea resulted in increased heat stability in non-concentrated milks, but corresponding concentrated milks showed a small decrease in maximum heat stability. It has not been possible to extrapolate heat stability data from non-concentrated to concentrated milks.
In the present investigations the storage effect the AcD-AG stabilizer on thrombocytes is examined. The thrombocytokinetic parameters of 9 fresh blood concentrates and 15 concentrates of AcD-AG plasma containing platelets were determined. Storage time amounted to three days. The results show that storage with AcD-AG is only possible to a limited degree. On an average the survival time of the platelets was reduced to 2.7 +/- 1.1 days compared with 9.0 +/- 1.0 days of fresh blood concentrates. The recovery of the stored platelets amounted to 25.3 +/- 16.1%, that of the fresh blood concentrates to 63.3 +/- 23.6%. The spleen-heart quotients and those of the liver-heart or the surplus impulses over the spleen and liver respectively indicate that there is a predominant destruction in the spleen for those thrombocytes stored for three days. The liver is scarcely involved in this sequestration process. With 36.1% platelet yield was very low in concentrates gained from AcD-AG plasma containing platelets and having been stored for 3 days. In cases of emergency a clinical application of concentrates prepared in this way should not be given up. If being used, the greater requirement has to be taken into account. If the substitution therapy is continued, however, fresh blood concentrates have to be used as soon as possible.
By means of a laser-interferometrical method diffusion layers at the interface of a noncharged cellulose membrane are studied. These layers are induced by a concentration difference between the NaCl solutions separated by the membrane. The temporal and local shift of the NaCl concentration in the diffusion layers were measured. A steady-state concentration profile could be obtained for times of 121 sec less than or equal to to less than or equal to 484 sec. The concentration profiles at any time (to less than or equal to 900) are not a linear function of the membrane surface, but could be fitted to a quadratic function. The thickness of the diffusion layers is also a function of time and its stationary value in this system is (575 +/- 49) X 10(-6)m. The role of concentration polarization for the determination of phenomenological thermodynamic coefficients of membranes is discussed and a new method is suggested, which excludes the difficulties of the concentration polarization in the diffusion layers at the membrane.
To explore the effect of physiological elevations of glucagon on plasma triglyceride concentration, glucagon was infused for thirty minutes at 3.0 ng/kg/min into both normal and insulin dependent diabetic subjects. The effects of this hormonal infusion on plasma triglyceride, free fatty acids, glucose, and insulin were compared to a control saline infusion study. A differential effect of glucagon on plasma triglyceride concentration between normal and diabetic subjects was observed. In normal subjects, glucagon infusion was accompanied by a concomitant increase in endogenous insulin secretion and free fatty acid levels, and no observable effect on circulating plasma triglyceride concentration. In contrast, in diabetic subjects, no change in insulin or free fatty acid concentration occurred during glucagon infusion and circulating plasma triglyceride concentration declined after twenty minutes of hormone infusion. These results suggest that plasma triglyceride concentration may be modulated, at least in part, by alterations in circulating plasma glucagon in concert with insulin secretion and free fatty acid availability in man.
1. A simple method is described for calculating the free concentrations of all species in a mixture of several ionic components that associate at equilibrium to any extent and with any stoicheiometry. 2. It can readily be adapted to take account of species such as protons for which the free rather than the total concentrations are controlled. 3. It was applied to mixtures of adenine nucleotides, Mg2+ and other ions relevant to the study of glucokinase (EC 2.7.1.2), but the qualitative conclusions are not peculiar to this system. 4. ATP exists in a high and nearly constant proportion (about 80%) as MgATP2- in solutions in which the total MgCl2 concentration exceeds the total ATP concentration by 1-10 mM. 5. By contrast, the proportion of ATP present as MgATP2- varies greatly if the total MgCl2 and total ATP concentrations are varied in constant proportion.
Model-dependent relationships describing the effects of absorption rate and dosing interval on steady-state phenytoin plasma concentrations are presented and discussed. Utilizing a range of operative Michaelis-Menten parameters that characterize phenytoin elimination via a single capacity-limited pathway, a situation assuming instantaneous absorption (case I) is compared with the situation in which continuous constant-rate absorption occurs (case II). The results of these comparisons demonstrate that average steady-state concentrations do not differ significantly between the two cases. Ratios (case I/case II) of areas under the curve during a steady-state dosing interval substantially deviating from unity are associated with high plasma clearances and clinically low phenytoin concentrations. When the same daily dose is maintained, but the dosing interval is altered (0.25, 0.33, 0.50, 1.0 day), little difference in the average steady-state levels is observed even when absorption is instantaneous. Differences between steady-state maximum and minimum concentrations increase with prolonged dosing intervals as well as faster absorbed phenytoin formulations, but for most patients these fluctuations are therapeutically insignificant. A dimensionless parameter, Q, which is a function of the individual patient's parameters and the dosing regimen, is introduced, and its relationship with steady-state phenytoin concentrations is discussed. Formulation-related differences in phenytoin dissolution rates that may result in significantly altered absorption rates should not affect average steady-state levels unless the extent of absorption is altered. More frequent dosing is not necessary to avoid increases in the average steady-state levels when rapidly absorbed phenytoin products are administered, but may be desirable if the required daily dose is high or the individual patient exhibits a narrow therapeutic range for this drug.
In anaesthetized rats, jejunal segments 30 cm in length were perfused (rates:0.1, 0.2,0.5 ml/min) with solutions containing antipyrine, salicylic acid, urea, L-lysine, L- and D-phenylalanine. The intraluminal concentration was determined approx. 10, 20, and 30 cm from the inflow cannula. The intraluminal concentration gradients were almost exponential and corresponded to the gradient predicted for a laminar flow through a solute-permeable circular tube. This gradient has a slightly greater curvature than the exponential one. Theoretical considerations showed that the logarithmic mean (Co-Cz)/ln(Co/Cz) of the in- and outflow concentration is the best average value for application in non-integrated absorption equations. This is also valid for the temporal concentration gradient after single administration of a substance into an intestinal segment.