Effect of cardiopulmonary bypass on cefazolin disposition

Cefazolin kinetics was studied in 8 patients the day before (PREOP), during (SURG), and the day after (POSTOP) cardiopulmonary bypass (CPB) surgery. PREOP (48.6 ml/min) and POSTOP (46.6 ml/min) total body clearances were of the same order and both were greater than the SURG (27.4 ml/min) total body clearance. Since cefazolin is almost entirely eliminated by the kidney, the lower SURG clearance is a result of reduced renal elimination, as confirmed by measuring cefazolin SURG (28.7 ml/min) and POSTOP (52.9 ml/min) renal clearance. The reduction in cefazolin renal elimination was the same throughout the surgical procedure, including the period of extracorporeal circulation. Cefazolin distribution was altered by the operative procedure as evidence by a higher SURG steady-state volume of distribution. This increase in apparent cefazolin distribution volume brought about by surgery was not seen with cephalothin, which was investigated by us in a similar group of patients. The different effect of CPB surgery on cefazolin and cephalothin distribution may be due to differences in plasma protein binding.

Compensatory adrenal hypertrophic response in fetuses of calorie-malnourished rats

Fetuses of ad libitum fed and calorie-restricted rats were unilaterally adrenalectomized on day 19. By day 20 ad libitum fed fetuses exhibited compensatory adrenal hypertrophy, but calorie-restricted fetuses did not. As this may be due to the elevated corticosteroid levels of the calorie-restricted dams, unilateral adrenalectomy was performed on fetuses of control and restricted rats bilaterally adrenalectomized on day 15. Fetuses of restricted and control rats exhibited compensatory hypertrophy. One effect of calorie restriction may be to increase the amount of maternal corticosteroids acting on the fetus.

Outcome of normal and dysfunctional labor in different racial groups

Spontaneous labor in patients of different racial groups has been studied relating progress and outcome to whether labor was dysfunctional as defined by the partogram and action line. Forty-three percent of primigravidas and 17.6 to 25.8% of multigravidas passed the action line and had a lower admission cervical dilatation and a longer observed first stage than those patients whose labor progress remained to the left of the action line. White and black primigravidas whose labor progressed to the right of the action line had lower 1 and 5 minute Apgar scores and delivered heavier babies than those to the left. The cesarean section rates were 1.6% and 1.4% (left) and 7.6% and 18.2% (right) in white and black primigravidas, respectively. The cesarean section rate was significantly higher in black primigravidas irrespective of the relationship to the action line due to the high incidence of the complications of hypertension such as fetal distress and abruptio placentae in those in normal labor as well as those in dysfunctional labor due to cephalopelvic disproportion in those patients whose cervimetric progress went to the right of the action line.

Fluorinated retinoic acids and their analogues. 1. Synthesis and Biological activity of (4-methoxy-2,3,6-trimethylphenyl)nonatetraenoic acid analogues

(4-Methoyx-2,3,6-trimethylphenyl)nonatetraenoic acids, esters, and amides (analogues of retinoic acid) bearing a fluorine atom(s) or a trifluoromethyl group on the polyene side chain were synthesized. The biological activities of these compounds and of 10-, 12-, and 14-fluororetinoic acid esters were evaluated in vivo in a chemically induced mouse papilloma test; the toxicities were assessed in an in vivo mouse hypervitaminosis A test. Antipapilloma activity greater than the parent nonfluorinated ester was found for 1c (ethyl 12-fluororetinoate) and 23 and 39 (aromatic 4- and 6-fluororetinoid esters, respectively). A similar increase in antipapilloma activity was observed for 71 and 72, the aromatic 4- and 6-fluororetinoic acids, respectively, relative to 2 and for 73 (aromatic 4-fluororetinoid amide) relative to 4.

One-way mixed lymphocyte culture: differences between Chinese and Caucasian stimulator cells

In "standardized" one-way mixed lymphocyte cultures, a pool of blood lymphocytes from randomly chosen Chinese subjects was a significantly stronger stimulus to Caucasian responder lymphocytes than was a pool of allogeneic cells from Caucasians. In contrast, Chinese lymphocytes did not respond more strongly to Caucasian cells than to Chinese cells. This could not be explained by an inherent racial difference in the capacity of blood lymphocytes to undergo blastogenesis. The implications of these findings for organ transplantation and routine testing of cell-mediated immune function are discussed.

5-Azacytidine hydrolysis kinetics measured by high-pressure liquid chromatography and 13C-NMR spectroscopy

Hydrolysis of 5-azacytidine, an experimental anticancer drug, in aqueous buffers was measured using a high-pressure liquid chromatographic (HPLC) procedure and a 13C-NMR method. The former utilized a 17.5-micron Aminex A-6 strong cation-exchanger column eluted with 0.4 M, pH 4.6 ammonium formate buffer at a flow rate of 0.4 ml/min. The hydrolysis sequence as well as the existence of a labile intermediate, N-formylguanylribosylurea, was unequivocally established using 6-13C-5-azacytidine and NMR spectral techniques. A reversible ring opening step to the N-formylguanylribosylurea with an equilibrium constant of 0.58 +/- 0.03 between pH 5.6 and 8.5, followed by an irreversible formation of guanylribosylurea, was found by HPLC. The data confirm previous assumptions on the hydrolytic kinetics. The pH dependency of hydrolysis was examined, and the hydrolysis profile gave a normal V shape with the most stable pH at 7.0. Rather stable intravenous dosage forms can be formulated.

Cephalothin kinetics: before, during, and after cardiopulmonary bypass surgery

Cephalothin kinetics was studied in 5 patients the day before (PREOP), during (SURG), and the day after (POSTOP) cardiopulmonary bypass surgery. The PREOP (114 ml/min) and SURG (94 ml/min) renal clearances were of the same order but both were less than POSTOP renal clearance (248 ml/min). Cephalothin total body clearance during operation was lower (p less than 0.01) than PREOP or POSTOP clearance, with decreased metabolic clearance the primary cause. There was reduction in cephalothin elimination throughout the surgical procedure, not only in the period of extracorporeal circulation, indicating that general anesthesia had a significant influence on drug disposition. The metabolite deacetylcephalothin was rapidly formed on all 3 days and its kinetic behavior paralleled that of the parent drug.

Quantitative thin-layer chromatography: thin-film fluorescence scanning analysis of adriamycin and metabolites in tissue

A rapid, non-hydrolytic thin-film fluorescence scanning method is described for the quantitation of adriamycin and metabolites in tissues. Adriamycin, with daunomycin added as the internal standard, was extracted from tissue homogenate which contained 500 micrograms of oxalic acid, with ice-cold 0.5 N hydrochloric acid--85% isopropanol, separated by thin-layer chromatography, and quantitated in situ via a fluorescence scanning technique. This method has a sensitivity to 0.05 microgram per gram of tissue.

GLC--mass spectrometry of several important anticancer drugs II: doxorubicin and daunorubicin aglycone analogs

By using previously developed pertrimethylsilylation and methoxime formation procedures, the GLC--mass spectra of pertrimethylsilyl and pertrimethylsilyl methoxime derivatives of 12 doxorubicin and daunorubicin glycone analogs, mostly synthesized in this laboratory, were studied. The fragmentation pathways were readily interpretable, and the patterns were highly specific for corresponding structural changes, thus supporting the previous contention that this method has potential for the identification of doxorubicin and daunorubicin metabolites. Four aglycone metabolites were identified, on the basis of their GLC--mass spectra, in the hydrolysate of the 1-butanol extract of bile obtained from a doxorubicin-treated rabbit.

GLC--mass spectrometry of several important anticancer drugs I: pertrimethylsilylation and O-methoxime formation

Procedures are reported for the formation of pertrimethylsilyl and pertrimethylsilyl methoxime derivatives of the aglycones of doxorubicin, daunorubicin, carminomycin, chromomycin A3, and mithramycin. The mass spectra are consistent with the formation of these derivatives. Fragmentation patterns highly specific for these derivatives are proposed, and the potential application for the identification of metabolites of these compounds is discussed.

Prediction of adriamycin disposition in cancer patients using a physiologic, pharmacokinetic model

A ten-compartment flow-limited pharmacokinetic model scaled from rabbit tissue distribution data was used to predict plasma adriamycin concentrations in 23 patients and adriamycin tissue uptake in nine surgery patients following iv bolus doses of 10--60 mg/m2. The predicted concentrations were compared to experimentally determined adriamycin using a specific thin-layer chromatographic fluorescence scanning procedure. The predicted plasma time course for 11 of 16 patients with relatively normal liver and kidney function agreed closely with the observed plasma time course. Deviations in the other five patients were ascribed to possible changes in the profile of metabolite formation and/or fluctuations in biliary clearance. All four patients with elevated serum bilirubin demonstrated significantly higher and more prolonged plasma levels than predicted. The results of two patients with impaired kidney function and one patient with both hepatic and renal involvement were inconclusive. The comparison between predicted and observed tissue concentrations in biopsy samples was varied; however, all were within an order of magnitude. It is concluded that the model depicts adriamycin uptake and distribution reasonably well; however, more needs to be known concerning individual variation in metabolic and biliary excretion rates for this to become more patient-specific. Also, a tumor compartment appears to be an important addition in modifying the model to allow for clinical utility.

High-presssure liquid chromatographic determination of methotrexate and its major metabolite, 7-hydroxymethotrexate, in human plasma

A rapid high-pressure liquid chromatographic assay is described for the analysis of methotrexate (MTX) and its major metabolite, 7-hydroxymethotrexate (7-OH-MTX), in plasma samples from patients following high-dose therapy. The method involves an ion-pair extraction of MTX from plasma with chromatography on a microparticulate anion-exchange column using ultraviolet detection at either 254 or 315 nm. Maximum sensitivity achieved was 1 X 10(-7) M. In addition to being specific for parent MTX, this procedure was used to detect and quantitate significant concentrations of 7-OH-MTX in several patients. Comparison to a protein-binding method indicated a greater degree of specificity for the chromatographic procedure. The procedure can be used to allow therapeutic monitoring of plasma MTX and metabolite for patients receiving high-dose MTX therapy as well as to determine the purity of formulations of MTX used clinically. In addition, the procedure is applicable to the support of pharmacokinetic studies of MTX in animals and man.

Immediate post-placental insertion of intrauterine contraceptive devices

Insertion of one of three types of intrauterine contraceptive device--the Lem, copper 7, and 'Progestasert' system--was carried out in 274 obstetric patients. These devices were all inserted within 20 min of delivery of the placenta and membranes, with a special 25 cm inserter. The expulsion-rate was low (less than 7%), and there were no uterine perforations. There was no difference in puerperal morbidity between these patients and a matched control group, and no cases of pelvic sepsis developed.

Synthesis of 5-azacytidine-6-13C and -6-14C

5-Azacytidine (1) labeled with 13C or 14C at the chemically labile C-6 position was synthesized. A method utilizing hydrolytic opening of the triazine ring followed by recyclization with dimethylformamide dimethyl acetal was used. Urinary and biliary excretion was measured in rabbits following intravenous doses of 1-4-14C and 1-6-14C. Differences in recoveries of the dose from 4-14C and 6-14C demonstrate that ring cleavage of 1 with loss of the C-6 carbon represents a major metabolite route.

Rapid analytic method for adriamycin and metabolites in human plasma by a thin-film fluorescence scanner

A rapid and highly sensitive method is described for the quantitative determination of adriamycin and metabolites in plasma. Adriamycin (Ad) with daunorubicin added as the internal standard was extracted from plasma with chloroform-isopropanol (1:1), separated by thin-layer chromatography (TLC), and quantitated in situ via a fluorescence scanning technique. This method represents one of the very few reliable quantitative TLC methods and is suitable for the routine determination of Ad in plasma in amounts as low as 2 ng/ml. Plasma Ad levels at 24 hours in rabbits and in patients both given a 1-mg/kg dose, previously regarded as difficult to be measured, are now easily measurable using as little as 0.5 ml of plasma. Multiple samples (ten to 15) can be analyzed by this method within a day.

A photosensitve daily rhythm in the female medaka, Oryzias latipes

Adult female medaka, Oryzias latipes, with regressed ovaries were exposed to 7 h of continuous light plus an additional hour of light at different times during the dark period of a 24-h cycle (7 + 1 light: 16 dark) at 24 ± 1 °C. When this additional hour of light falls on the 16th h, counting the onset of the light period as the 0 h, ovarian development was induced. This ovarian development is enhanced when the exposure period is increased and when the fish are preexposed to a warm temperature. The use of a photosensitive daily rhythm to measure photoperiod and to time the spawning season in the medaka is suggested.

Carbon-13 nuclear magnetic resonance spectroscopy. Structure of the anticoagulant warfarin and related compounds in solution

Carbon-13 nuclear magnetic resonance spectra have been obtained for the coumarin-related compounds warfarin and phenprocoumon. The spectral assignments indicate that warfarin exists as a mixture of cyclic hemiketal diastereomers in dimethyl sulfoxide solution. The sodium salt of warfarin exists as the ringopen form in water solution.

Warfarin. Stereochemical aspects of its metabolism and the interaction with phenylbutazone

An examination of the metabolic fate of the R and the S isomers of warfarin revealed that the two isomers were metabolized by different routes. R warfarin was oxidized to 6-hydroxywarfarin and was reduced to the (R,S) warfarin alcohol. In contrast, S warfarin was oxidized to 7-hydroxywarfarin and was reduced to the (S,S) warfarin alcohol. S warfarin was also oxidized to 6-hydroxywarfarin. These observations suggested that interactions between warfarin and other drugs might be manifest stereo-specifically, i.e., have a different effect on the isomers of warfarin, so a series of experiments were conducted with each isomer of warfarin, before and after phenylbutazone. The plasma clearance of S warfarin was slowed from 3.1 to 1.1% per h in one subject and from 2.3 to 1.6% per h in another. In contrast, the clearance of R warfarin was increased from 1.5 to 3.0% per h and from 0.9 to 1.6% per h in two subjects after phenylbutazone. The rate of clearance of racemic warfarin was unaffected by phenylbutazone; the depression of the rate of clearance of the S isomer masked the stimulation of the clearance of the R isomer. Since S warfarin is five times more potent an anticoagulant than R warfarin, it is concluded that inhibition of the metabolism of S warfarin provides one mechanism for the augmented anticoagulation which follows phenylbutazone.