Pharmacokinetics of 1-(5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1- piperazinyl)-1,4-dihydro-4-oxoquinolone-3-carboxylic acid hydrochloride (DW-116), a new quinolone antibiotic in rats

The objectives of this study were to characterize the pharmacokinetics of 1-5-fluoro-2-pyridyl)-6-fluoro-7-(4-methyl-1- piperazinyl)-1,4-dihydro-4-oxoquinolone-3-carboxylic acid hydrochloride (DW-116), a newly developed quinolone antibiotic, and to compare these kinetics with those of ciprofloxacin and rufloxacin, representative quinolone antibiotics, in rats. Rats were subjected to surgery involving catheterization of the femoral vein and artery. DW-116 (4, 20, or 200 mg/kg), ciprofloxacin (20 mg/kg), or rufloxacin (20 mg/kg) was administered either intravenously (iv) or orally. Blood samples were collected at various times and subjected to an HPLC assay for the quinolones. Temporal profiles of plasma concentration after iv administrations of DW-116 at doses of 4, 20, and 200 mg/kg exhibited an apparent multiexponential decline. In the three doses examined, systemic clearance and steady-state volume of distribution of DW-116, calculated by model-independent methods, were in the range 0.17 approximately 0.23 L/h/kg and 2.90 approximately 4.44 L/kg, respectively. When DW-116 was given orally at doses of 4, 20, or 200 mg/kg, the AUC values were nearly identical to those following iv administration, indicating an almost complete absorption (i.e., the percent bioavailability was 90.0 for 4 mg/kg, 99.0 for 20 mg/kg, and 98.3 for 200 mg/kg) in the dose range examined. The absorption of DW-116 appears to be extremely rapid because the mean residence time calculated from the oral administration data was not significantly different from that for the iv administration. At a dose of 20 mg/kg, the mean residence time for iv administered ciprofloxacin and rufloxacin was smaller than that of DW-116, indicating that DW-116 remains in the body longer than the other quinolones. Absolute percent bioavailabilities of ciprofloxacin (69.9%) and rufloxacin (84.9%) were smaller than that obtained for DW-116 (99.0%). Because it has been reported that the in vivo antibacterial activity of DW-116 is comparable or superior to that of rufloxacin and ciprofloxacin, despite the fact that the in vitro activity is significantly lower, the pharmacokinetics of this antibiotic may be responsible, at least in part, for the enhanced in vivo antibacterial activity of DW-116.

Taurine transport in cultured choroid plexus

PURPOSE

Taurine, a beta-amino acid, is a neuromodulator which interacts functionally with the glycinergic, GABAergic, cholinergic and adrenergic systems. Although a continuous cell culture model is not available for the choroid plexus epithelia, we recently described a primary cell culture of rabbit choroid plexus epithelia. The goal of the current study was to determine the suitability of this primary cell culture for the study of the Na(+)-taurine transporter in the rabbit choroid plexus.

METHODS

A primary cell culture of rabbit choroid plexus epithelial cells was grown on semi-permeable filters and kinetics of 3H-taurine uptake were ascertained.

RESULTS

Taurine transport in the cultured choroid plexus cell was Na(+)-dependent and saturable (Km = 156 microM). The beta-amino acids, beta-alanine and taurine, significantly inhibited Na(+)-driven taurine transport whereas L-alanine partially inhibited taurine transport in the cultured cells. In addition, we observed that the activity of the Na(+)-taurine transporter is affected by exposure to taurine in the media.

CONCLUSIONS

These results-demonstrate that a Na(+)-taurine transporter with characteristics similar to those in the intact tissue is expressed in cultured choroid plexus epithelial cells. The transporter may undergo adaptive regulation and play a role in taurine homeostasis in the central nervous system.

Comprehensive life table of computer-assisted predictive mathematical relationship between age and life expectancy, survival probability or death rate in US adults

A microcomputer program in BASIC for predicting life expectancy by age in US adults was designed. Formulas used in this study were derived from the data reported by the National Center for Health Statistics. A comprehensive life table that shows the relationship between age and death rate, survival probability or life expectancy for each year between 25 and 85 years of age was obtained in this study, using a newly designed computer program for predicting life expectancy by age and the program for survival probability previously published by the author. The comprehensive life table may be useful for clinical evaluation of patients and further helpful for biomedical investigation and epidemiological evaluation of US adults.

In vitro effect of meconium on the physical surface properties and morphology of exogenous pulmonary surfactant

The pathophysiology of meconium aspiration syndrome(MAS) is related to mechanical obstruction of the airways and to chemical pneumonitis. Meconium is also suggested to cause functional deterioration of pulmonary surfactant. Recent studies have reported that meconium inhibits the physical surface properties of pulmonary surfactant, and that administration of exogenous surfactant may provide therapeutic benefits in animal models or infants with respiratory distress due to MAS. To assess the effects of meconium on physical surface properties, especially the changes on the air-liquid interface and hypophase of pulmonary surfactant in vitro, we studied the following findings; a) the surface spreading rate(SSR) and the surface adsorption rate(SAR), b) the viscosity, c) the electron microscopic changes, on a series of mixtures with various concentrations of lyophilized human meconium and Surfactant-TA(SurfactenTM). The human meconium has significantly increased the surface tension of SSR and the viscosity of pulmonary surfactant, but had decreased the surface pressure of SAR of surfactant, and changed the electron microscopic findings of surfactant. We have concluded that these findings support the concept that meconium-induced surfactant dysfunction may play a role in the pathophysiology of MAS.

Rectal absorption of omeprazole from suppository in humans

The oral absorption of omeprazole is incomplete, in part due to first-pass metabolism. We investigated the feasibility of rectal administration of omeprazole by comparing its absorption from a Witepsol H15-based rectal suppository and an orally administered commercial gelatin capsule in 10 male volunteers. Profiles of plasma concentration between two preparations (20 mg) were not statistically different, indicating that the rate and the extent of absorption were similar. Paired t-test revealed no significant differences in area under the curve, mean residence time, and time to peak concentration between two preparations. On the other hand, lag time of absorption and peak concentration were statistically different (p < 0.05) between these preparations. Under these experimental conditions, the rectal route did not produce an improvement in the extent of absorption over an oral capsule.

Exogenous pulmonary surfactant replacement therapy in a neonate with pulmonary hypoplasia accompanying congenital diaphragmatic hernia--a case report

Pulmonary hypoplasia(PH) commonly occurs in association with oligohydramnios and other congenital anomalies, especially congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia is an important factor, as persistent pulmonary hypertension, in the prognosis of CDH. In some reports, there is a decrement of pulmonary surfactant in PH accompanying CDH. Recently, there are some reports that exogenous pulmonary surfactant therapy is effective in experimental animal model and neonatal respiratory distress with PH. We report a case of a 5 day-old male neonate, who had shown dyspnea and diagnosed as left pulmonary hypoplasia accompanying CDH. The CDH was surgically treated and the ipsilateral PH, with intratracheal administration of exogenous pulmonary surfactant postoperatively. After exogenous pulmonary surfactant application, the left lung volume was increased on chest roentgenogram and lung perfusion scan findings, and there was an improvement in oxygenation and clinical manifestations. We suggest that postoperative exogenous pulmonary surfactant replacement therapy is effective in the case of PH and further trials are needed to clarify the optimal dose and timing of supplementation of surfactant for treatment of infants with PH accompanying CDH.

Saturable disposition of taurine in the rat cerebrospinal fluid

Recently, we described a saturable Na(+)-dependent taurine transporter in the choroid plexus, the blood-CSF barrier (Chung et al., 1994). The goal of this study was to determine whether this transporter plays a role in the in vivo elimination of taurine from the CSF. 3H-taurine and 14C-inulin were injected into the lateral ventricle of anesthetized rats, and the concentrations of the radiolabeled compounds in the CSF were determined. The apparent clearance of taurine from the CSF was greater than the estimated CSF bulk flow (P < .005), which indicates that there is a clearance process in addition to the CSF bulk flow. Taurine distribution into the choroid plexus was at least 10-fold higher than that found in other brain areas. The apparent clearance of 3H-taurine and the distribution of taurine into the choroid plexus and cerebral cortex were dose-dependent. The Michaelis-Menten rate constant estimated from the in vivo elimination study (40 +/- 25 microM) is in the range of that obtained for taurine uptake in isolated choroid plexus tissue slices (137 +/- 67 microM). Both alpha- and beta-alanine decreased the clearance of taurine from the CSF as well as the distribution of taurine into the choroid plexus via inhibitory effects (either direct or indirect) on the Na(+)-taurine transporter in the choroid plexus. These data suggest that the previously characterized taurine transporter in the choroid plexus plays a role in the in vivo saturable disposition of taurine in the CSF.

Choice of antibiotics by the site of infection in a community hospital

A total of 1578 culture and antimicrobial susceptibility results on clinical specimens from various sites of infection were analyzed, by using the software installed in the MicroScan System of an automated microbiology analyzer, and by mathematical calculation. A list of antimicrobial drugs of choice by the site of infection is determined on the basis of the computer and mathematical analysis of the above data. The list suggested in this in vitro study may be useful to clinicians for selection of an initial antimicrobial agent in hospitals or communities when an infection is suspected in a site of infection before the results of cultures and antimicrobial susceptibility tests are reported. This list may also be helpful for initial therapy in critically ill patients before ordering culture and susceptibility testing, as well as for preoperative prophylaxis.

Formulas expressing life expectancy, survival probability and death rate in life table at various ages in US adults

The National Center for Health Statistics (Monthly Vital Statistics Report, 41 (1993) 1-36; Pediatrics, 92 (1993) 743-754) reported the life table for the total population of the United States, 1992, on the basis of vital statistics. The life table shows life expectancy, survival and death rate at various ages. Formulas expressing death rate, survival probability and life expectancy at various ages in US adults are constructed from the data of the National Center for Health Statistics (NCHS). A mathematical model of the 'probacent'-probability equation previously published by the author is employed in this study. Analysis of the computer-assisted predicted values and the data reported by the NCHS indicates that the formulas are accurate and reliable with a close agreement in expressing death rate, survival probability and life expectancy at various ages in US adults of 25 years of age and older. The formulas can determine the relationship between the age and the death rate, the survival probability or the life expectancy and may be of value for epidemiologic evaluation of US adults.

Thioredoxin-dependent peroxide reductase from yeast

A 25-kDa antioxidant enzyme that provides protection against oxidation systems capable of generating reactive oxygen and sulfur species has previously been identified. The nature of the oxidant eliminated by, and the physiological source of reducing equivalents for, this enzyme, however, were not known. The 25-kDa enzyme is now shown to be a peroxidase that reduces H2O2 and alkyl hydroperoxides with the use of hydrogens provided by thioredoxin, thioredoxin reductase, and NADPH. This protein is the first peroxidase to be identified that uses thioredoxin as the immediate hydrogen donor and is thus named thioredoxin peroxidase (TPx). TPx exists as a dimer of identical 25-kDa subunits that contain 2 cysteine residues, Cys47 and Cys170. Cys47-SH appears to be the site of oxidation by peroxides, and the oxidized Cys47 probably reacts with Cys170-SH of the other subunit to form an intermolecular disulfide. Mutant TPx proteins lacking either Cys47 or Cys170, therefore, do not exhibit thioredoxin-coupled peroxidase activity. The TPx disulfide is specifically reduced by thioredoxin, but can also be reduced (less effectively) by a small molecular size thiol. The Saccharomyces cerevisiae thioredoxin reductase gene was also cloned and sequenced, and the deduced amino sequence was shown to be 51% identical with that of the Escherichia coli enzyme.

Formulas expressing relationship among age, height and weight, and percentile in Saudi and US children aged 6-16 years

A microcomputer program in BASIC for predicting percentile of height and weight by age for Saudi and US children aged 6-16 years is designed. The formulas used in this program are derived from the data reported by Magbool et al. (Ann Saudi Med 13 (1993) 344-349) and the data of the National Center for Health Statistics (NCHS). Magbool et al. reported measurements of height and weight of 21,638 Saudi boys and girls aged 6-16 years from the Eastern Province. A mathematical model and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted, predicted values and the data reported by Magbool et al. (Saudi) and the NCHS (USA) indicates that the program is accurate and reliable with a close agreement in expressing percentile as a function of age and height or weight. The computer-assisted predictive formulas can determine the relationship among the age, the height and weight, and the percentile, and as a supplement to the clinically useful reference standards of the tables and figures of Magbool et al. and the NCHS may be of value for growth evaluation of Saudi and US children.

Formula expressing a relationship among lesion thickness and time after diagnosis and survival probability in patients with malignant melanoma

A microcomputer program in BASIC for predicting the survival probability as a function of lesion thickness and time after diagnosis is designed. The New York University-Melanoma Cooperative Group (NYU-MCG) shows 10-year survival rates of patients with malignant melanoma broken into four lesion-thickness groups (Cancer Journal for Clinicians, 41 (1991) 201-226). The formula used in this program is derived from the survival data of NYU-MCG. A mathematical 'probacent'-probability model previously published by the author is employed in this study. Analysis of the computer-assisted predicted and the NYU-MCG reported survival probability data indicates that the program is accurate and reliable with a close agreement in expressing survival probability and that it may be of value for prognostic evaluation of patients.

A modified product inhibition model describes the nonlinear pharmacokinetics of nicorandil in rats

Nicorandil, a vasodilator which acts through both cyclic GMP accumulation and K+ channel opening, has been used in the treatment of various cardiovascular diseases. We have examined the pharmacokinetics of nicorandil in the rat as a function of dose, as both i.v. boluses (9 doses, 0.75-12 mg, n = 1.4 per dose), and as a 5-hr infusion followed by a 5-hr washout (6 doses, 10-500 micrograms/kg/min, n = 3 per dose). Plasma nicorandil concentrations were determined by HPLC. Nicorandil plasma concentrations increased disproportionately with dose, but nicorandil elimination obeyed apparent monoexponential kinetics, and the apparent half-life (t1/2) increased with dose. In addition, the approach to apparent steady-state during the infusion phase was not overtly sensitive to the drastic changes in t1/2 observed. Pharmacokinetic modelling with several nonlinear models, viz: Michaelis-Menten with parallel first-order, cosubstrate depletion and competitive product inhibition, were carried out. Addition of the sulfhydryl donor, N-acetyl-L-cysteine, did not change the pharmacokinetics of nicorandil, providing experimental indication that a cosubstrate depletion model might not be applicable. To described the unique pharmacokinetics, a modified product inhibition model was developed. This new model includes the classic competitive product inhibition equation, describing both parent and product kinetics, and it incorporates, in addition, separate first-order elimination rate constants for both nicorandil and the inhibition metabolite. Experimental evidence showed that N-(2-hydroxyethyl) nicotinamide, the major metabolite of nicorandil in rats, and nicotinamide (niacinamide) itself, indeed inhibited nicorandil elimination.

Characterization of a sodium-dependent taurine transporter in rabbit choroid plexus

Taurine, a beta-amino acid, plays an important role as a neuromodulator and is necessary for the normal development of the brain. Since de novo synthesis of taurine in the brain is minimal and in vivo studies suggest that taurine does not cross the blood-brain barrier, we examined whether the choroid plexus, the blood-cerebrospinal fluid barrier, plays a role in taurine transport in the central nervous system. The uptake of [3H]taurine into ATP-depleted choroid plexus from rabbit was substantially greater in the presence of an inwardly directed Na+ gradient, whereas in the absence of a Na+ gradient taurine accumulation was negligible. A transient inside-negative potential gradient enhanced the Na(+)-driven uptake of taurine into the tissue slices, suggesting that the transport process is electrogenic. Na(+)-driven taurine uptake was saturable with an estimated Vmax of 111 +/- 20.2 nmol/g per 15 min and a Km of 99.8 +/- 29.9 microM. The estimated coupling ratio of Na+ and taurine was 1.80 +/- 0.122. Na(+)-dependent taurine uptake was significantly inhibited by beta-amino acids, but not by alpha-amino acids, indicating that the transporter is selective for beta-amino acids. Na(+)-dependent taurine uptake showed some selectivity for anions: the accumulation was comparable in the presence of Cl-, Br- and thiocyanate whereas I-, SO4(2-) and gluconate did not stimulate the uptake significantly. Collectively, our results demonstrate that taurine is transported in the choroid plexus via a Na(+)-dependent, saturable and apparently beta-amino acid selective mechanism. This process may be functionally relevant to taurine homeostasis in the brain.

Formulas predicting survival in patients with heart transplantation

Kirklin et al. (J Heart Transpl. 7 (1988) 331-336) reported survival data in 132 patients who underwent heart transplantation. Survival was evaluated by using the product-limit method of Kaplan-Meier and maximum likelihood method. In addition, the effect of pulmonary vascular resistance on survival was estimated by using multivariate analysis. A microcomputer program in BASIC for predicting the survival probability after transplantation in patients with heart transplantation is designed. The formula used in this program is derived from the survival data reported by Kirklin et al. (J Heart Transpl. 7 (1988) 331-336). A mathematical model of the 'probacent'-probability equation and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted values and the data reported by Kirklin et al. (J Heart Transpl. 7 (1988) 331-336) indicates that the program is accurate and reliable with a complete agreement in expressing survival probability as a function of time after heart transplantation. The computer-assisted predictive formula can determine the relationship between the time and the survival probability and may be of value for prognostic evaluation of patients. The computer-assisted mathematical model of the 'probacent'-probability equation may be proposed as a general approximation method to make useful predictions of probable outcomes in various biomedical phenomena.

Relationship between nitroglycerin-induced vascular relaxation and nitric oxide production. Probes with inhibitors and tolerance development

We have shown previously that nitric oxide (NO) is generated from nitroglycerin (NTG) through enzyme-mediated reactions in the bovine coronary artery smooth muscle cell, but it is not known whether this metabolic conversion plays a significant role in the pharmacologic action of NTG, viz. relaxation. In this study, we developed a technique that allowed direct measurement of NO from intact bovine coronary arterial rings that were incubated previously with NTG, and examined whether changes in NTG-induced relaxation were accompanied by parallel changes in NO generation. Co-incubation of the vascular preparations with a potent inhibitor of glutathione-S-transferases (GSTs), bromosulfophthalein (up to 200 microM), did not affect NTG-induced relaxation, nor did it alter NO generation from NTG in the preparation. In contrast, 1-chloro-2,4-dinitrobenzene (CDNB), a GST substrate, inhibited NO generation as well as the relaxation response of NTG in the intact vascular tissue preparation. CDNB, however, did not decrease the relaxant responses of nifedipine and isoproterenol. Thus, the inhibitory effect of CDNB on NTG-induced relaxation and NO production appeared specific. When bovine coronary rings were made tolerant to NTG by pretreatment with 0.44 mM NTG for 1 hr, the EC50 was shifted to the right 162-fold, and NO generation was also reduced in intact rings and tissue homogenates. However, when the homogenates were further subfractionated to microsomes and cytosols, or when homogenates were allowed to stand for a similar time period necessary for subfractionation, the difference in NO production from control versus tolerant tissue preparations disappeared. It is possible, therefore, that the NTG-induced tolerance process might have been partially reversed during this time period. Results of this study identified CDNB as an apparently specific inhibitor of NTG action, but showed that GST-mediated reactions were probably not involved in the metabolic activation of NTG. Our results also indicated that tissue NO generation from NTG was positively related to the relaxation responses generated by this nitrovasodilator.

Biochemical mechanism of organic nitrate action

Increasing evidence suggests that organic nitrate action derives from their metabolic conversion to nitric oxide (NO) in the vascular smooth muscle cell. The primary catalytic activity of this process appears to reside at the cellular plasma membrane. There is no concrete evidence to indicate that NO formation is preceded by the production of inorganic nitrite ion or that the NO produced needs to form S-nitrosothiols before it can activate guanylate cyclase to produce cyclic guanosine 3',5'-monophosphate (cGMP). Although sulfhydryl donors can partially reverse nitroglycerin-induced tolerance in patients, this phenomenon (by itself) is not sufficient to implicate intracellular sulfhydryl depletion as an operating mechanism of clinical nitrate tolerance. This is because sulfhydryl donors can react with nitroglycerin extracellularly to form S-nitrosothiols, and nonsulfhydryl compounds, such as enalapril and hydralazine, can prevent the development of in vivo nitrate tolerance. In addition to the cellular biochemical reactions, organic nitrates also produce systemic biochemical effects through altering neurohormonal status. These systemic effects may contribute significantly to the development of nitrate tolerance in therapeutic situations.

Relationship among age, serum cholesterol level and population percentile in adults

The data of the National Health and Nutrition Examination Survey comprehensively have shown that distributions of serum cholesterol levels in the US adult population are age and sex dependent. General formulas were constructed and published by the author on the basis of the data of the National Health and Nutrition Examination Survey to predict the population percentile for serum cholesterol levels by age. A mathematical model and a computer program previously published by the author were employed in the study. Analysis of the computer-assisted predicted and the National Health and Nutrition Examination Survey-reported percentiles indicated that the designed program for calculating the formulas was accurate and reliable. The formula could determine the relationship among adult age, serum cholesterol level and population percentile. A comprehensive table and nomograms that show the relationship among age, serum cholesterol level and population percentile in men and women for each year group between 20 and 79 years of age are obtained in this study, using the previously published formulas. The population percentiles predicted by the formula may reflect the relative degrees of risk for coronary heart disease. The population percentile, simultaneously expressed as 'risk percentile', may be used as a parameter of risk assessment for coronary heart disease for all adult ages and sexes. Seventy-five population percentile of serum cholesterol level is suggested as a cutoff point of high 'risk percentile' for coronary heart disease. This information on the percentile may have a preventive diagnostic value for detection, evaluation and treatment of patients with high cholesterol levels. The comprehensive table and nomograms showing the relationship among age, serum cholesterol level and population percentile may be hopefully available to clinicians and useful in their medical practice and may also be helpful in future clinical investigation.

A common enzyme may be responsible for the conversion of organic nitrates to nitric oxide in vascular microsomes

We compared the nitric oxide (NO)-generating behavior of nitroglycerin (NTG), pentaerythritol trinitrate (PEtriN) and isosorbide dinitrate (ISDN), in the microsomal preparation of bovine coronary artery smooth muscle cells. The comparative NO generating activities among these nitrates were consistent with their relative reported vasodilating activities. Consistent with our previous observations with NTG, 400 microM bromosulfophthalein did not affect NO generation from PEtriN and ISDN in vascular microsomes while 400 microM 1-chloro-2,4-dinitrobenzene completely inhibited NO generation from these nitrates. Gel filtration chromatography with solubilized microsomes of bovine aortic smooth muscle cells showed the primary activity of NO generation from all three nitrates to be eluted at about 200 kD, consistent with that found with solubilized microsomes from the bovine coronary artery microsomes. These results suggest that organic nitrates may be converted to NO by one common enzyme in vascular microsomes.

Conversion of nitroglycerin to nitric oxide in microsomes of the bovine coronary artery smooth muscle is not primarily mediated by glutathione-S-transferases

The pharmacological action of organic nitrate vasodilators [e.g., nitroglycerin (NTG)] is thought to be mediated through metabolic conversion to nitric oxide (NO); conversion leads to vasodilatation, whereas diminished conversion in chronic therapy may lead to pharmacological tolerance. The biochemical nature of this process, however, is poorly understood. Glutathione-S-transferases (GST) have been shown to metabolize organic nitrates in the liver, but it is not known whether these enzymes are involved in this pharmacologically relevant process. We, therefore, compared the activities of conversion of NTG to NO vs. those of GST in microsomal suspensions of bovine coronary artery smooth muscle tissue. A classical GST substrate, 1-chloro-2,4-dinitrobenzene, inhibited NO production in microsomes, suggesting possible involvement of GST in organic nitrate activation. However, GST activity derived from microsomes exhibited a different heat lability profile compared to that of NO generation. Known inhibitors of GST (viz., indomethacin and bromosulfophthalein) did not alter the NO-generating activity in microsomes. Glutathione was a critical cofactor for GST, but not for NO generation from NTG, and thiols other than glutathione (e.g., N-acetyl-L-cysteine and thiosalicylic acid) also could facilitate NO production. Moreover, comparison to a commercially available purified liver GST preparation showed that, at the same GST activity toward 1-chloro-2,4-dinitrobenzene, the microsomal incubation produced about 8 times more NO than the purified liver GST. Radiation inactivation analysis of the functional molecular sizes of GST and the NO-producing enzyme(s) suggested that the enzymes were of different molecular weights (54 kD and 160 kD, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Formula predicting survival in patients with acute myelogenous leukemia

A microcomputer program in BASIC for predicting the survival probability after diagnosis of acute myelogenous leukemia in patients is designed. Formulas used in this program are derived from the data published by Feigl and Zelen. A mathematical model and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted and the Feigl and Zelen's reported data has shown that the program is fairly accurate and reliable with close agreement in expressing survival probability as a function of white cell count and time after diagnosis.

Formula predicting survival in patients with invasive cutaneous malignant melanoma

Popescu et al. (Mayo Clin Proc., 65 (1990) 1293-1302) reported survival data in 107 patients who were diagnosed as having malignant melanoma during the years 1950-1985. Survival was evaluated by using the Kaplan-Meier method. A microcomputer program in BASIC for predicting the survival probability after diagnosis in patients with invasive cutaneous malignant melanoma is designed. A formula used in this program is derived from the survival data reported by Popescu et al. A mathematical model of generalized lognormal distribution and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted values and the data reported by Popescu et al. indicates that the program is accurate and reliable with a close agreement in expressing survival probability as a function of time after diagnosis. The computer-assisted predictive formula can determine the relationship between the time and the survival probability, and may be of value for prognostic evaluation of patients. The mathematical model representing the generalized lognormal distribution may be used as a method of parametric analysis of survival data of estimates determined by the nonparametric product-limit method of Kaplan-Meier in certain biological phenomena.

Formula predicting survival in mice inoculated with leukemia cells

A microcomputer program in BASIC for predicting the survival probability after inoculation of L1210 leukemia cells into mice is designed. Formulas used in this study are derived from the data published by Johnson et al. (J Natl Cancer Inst, 34 (1965) 277-290). A mathematical model and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted values and the reported data (J Natl Cancer Inst, 34 (1965) 277-290) on survival probabilities has shown that the program is accurate and reliable with a close agreement in expressing survival probability as a function of inoculum size and time after inoculation.

Formulas predicting the percentile of heart weights by body weight in subjects from birth to 19 years of age

The values reported by Scholz and his coworkers [Mayo Clin Proc, 63 (1988) 126-136,637] show that distributions of normal heart weights in the period of body growth from birth to 19 years of age are age and sex dependent and actually more dependent on body weight. General formulas are constructed on the basis of the values of Scholz and his coworkers to predict percentile in the population for heart weights by body weight. A mathematical model and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted values and the data on heart weights for specific body weights and percentiles reported by Scholz and his coworkers indicates that the designed computer program for calculating the formula is accurate and reliable. The formulas can determine the mathematical relationship among body weight, heart weight and population percentile. It seems to the author that the computer-assisted predictive formula has limited values in its clinical application since heart weights are to be evaluated practically only in autopsy service in pathology, but that a similar mathematical model as used in this study would be applicable in analysis of other clinical, age- and sex-dependent measurable parameters.

Formula predicting carcinoma-free probability in rats exposed to carcinogen DMBA

The Weibull distribution is a generalization of the exponential distribution. Pike (Biometrics, 22 (1966) 142-161) used the Weibull distribution in the analysis of carcinogenesis experiments on rats. A formula of conversion that allows mathematical conversion of the Weibull distribution to the generalized lognormal distribution is constructed in this study. This formula is applied to the Pike's data on carcinoma-free probability in rats exposed to carcinogen DMBA. A mathematical model and a computer program previously published by the author are employed in this study. Analysis of the computer-assisted predicted and the Pike's reported data on carcinoma-free probability indicates that a close agreement is present between both data. It seems to the author that a generalized lognormal distribution of the carcinoma-free probability in rats exposed to carcinogen can be derived from the formula of conversion. In addition the generalized lognormal distribution may be proposed as a method of parametric analysis of survival data on estimates by non-parametric product-limit method of Kaplan-Meier in certain biological phenomena.

Formulas predicting the percentile of serum cholesterol levels by age in adults

The data of the National Health and Nutrition Examination Survey comprehensively have shown that distributions of serum cholesterol levels in the US adult population are age and sex dependent. General formulas have been constructed on the basis of the data of the National Health and Nutrition Examination Survey to predict the adult percentile in the population for serum cholesterol levels by age. A mathematical model and a computer program previously published by the author were employed in this study. Analysis of the computer-assisted predicted and the National Health and Nutrition Examination Survey-reported percentiles indicated that the designed program for calculating the formula was accurate and reliable. The formulas can determine the relationship among adult age, serum cholesterol level, and population percentile. It has been reported that adult individuals tend to have persistently the same percentiles of their serum cholesterol levels in the population with increasing ages in the absence of cholesterol-altering intervention. The percentiles predicted by the formula may reflect the relative degrees of risk for coronary heart disease. This information on the percentile may have a preventive diagnostic value for the detection, evaluation, and treatment of patients with high cholesterol levels. The percentile may be used as a parameter of risk assessment for coronary heart disease for all adult ages and sexes. However, clarification of a probable relationship between high percentiles (like high cholesterol levels) and coronary heart disease, and justification of the use of percentiles as a risk parameter, must await further clinical investigation.

Identification of the subcellular site for nitroglycerin metabolism to nitric oxide in bovine coronary smooth muscle cells

The vasodilating action of nitroglycerin (NTG) is thought to be mediated by its metabolic activation to nitric oxide (NO) in the vascular smooth muscle cell, but the site at which this process occurs has not been defined. To determine which cellular component is primarily responsible for this metabolic activation, subcellular fractions of bovine vascular smooth muscle cells were prepared and incubated with NTG along with cofactors. Time-dependent headspace NO concentrations generated in these preparations were determined directly by chemiluminescence detection. A mathematical model was developed to relate headspace NO with the NO-generating activity in each incubation, correcting for the concurrent processes of NO partitioning between the headspace and the incubation medium, and NO degradation in these two phases. The estimated NO-generating activities from different subcellular fractions were well correlated with the activities of two enzyme markers of the plasma membrane (K(+)-activated ouabain sensitive p-nitrophenyl phosphatase and 5'-nucleotidase), but not with those of the mitochondria, endoplasmic reticulum or the cytosol. These results indicate that the enzyme(s) responsible for the metabolic activation of NTG, and possibly other organic nitrate vasodilators, are associated with the plasma membrane in bovine coronary smooth muscle cells.

Perifascicular atrophic fibers in childhood dermatomyositis with particular reference to mitochondrial changes

Ten of 17 muscle biopsy specimens from 15 patients with childhood dermatomyositis (DM) showed distinct perifascicular atrophy. The atrophic fibers showed the following characteristics: (1) decreased cytochrome c oxidase (CCO) activity, (2) rare positive reaction with acridine orange (AO) staining, (3) type 2C reaction in 7.9% (0.4-17.5%) of the fibers, (4) an increased number of activated satellite cells, (5) mitochondria which were increased in number but decreased in size, (6) a significantly decreased CCO activity in isolated mitochondria (51.6 +/- 30.3 nmol/min per mg mitochondrial protein) as compared with that in the controls (103.6 +/- 41.5). The major pathogenetic mechanism in muscles in childhood DM is thought to be ischemia due to involvement of the microvasculature. The presence of type 2C fibers and increased numbers of activated satellite cells reflect a focal repair process taking place concomitantly in the damaged myofibers. Mitochondrial enzyme defect, especially CCO deficiency is present not only in genetic disorders with mitochondrial involvement but in other neuromuscular disorders including inflammatory myopathies.

Formulas predicting carboxyhemoglobin resulting from carbon monoxide exposure

A microcomputer program in BASIC for predicting the percent carboxyhemoglobin of blood in men exposed to carbon monoxide is designed. Formulas used in this program are derived from the data reported by Forbes, Sargent and Roughton. A general formula previously published by the author expresses the mathematical relationship among the intensity of a stressor, the time of exposure, and the occurrence of a biological response. This formula is implemented in this study, using carbon monoxide as the specific stressor. Analysis of the reported and the computer-assisted predicted data has shown that the program for the constructed formulas is fairly accurate and reliable in expressing carboxyhemoglobin as a function of the air CO concentration and the time of exposure. The predictive formulas can determine the relationship among the carbon monoxide concentration in air, the time of exposure, and the percent carboxyhemoglobin level of blood, and may be of value in industry, in environmental protection and in medicine.

Early inhibition of the Na+/K+-ATPase ion pump during acetaminophen-induced hepatotoxicity in rat

The status of Na+ regulation was examined during early stages of alkylation insult to rat liver. Na+/K+-ATPase activity in plasma membranes declined by 52% within 3 hr of treatment with 850 mg/kg acetaminophen. This loss preceded the release of alanine aminotransferase (2880 +/- 1550 U/ml) and necrosis (2+) seen at 24 hr. Activities of 5'-nucleotidase and Mg2+-ATPase and recovery of plasma membranes were comparatively unchanged at 3 hr. Because damage to Na+/K+-ATPase appeared early in the pathogenesis of acetaminophen hepatotoxicity, loss of hepatocellular Na+ regulation could represent one of the critical molecular consequences of lethal alkylation by acetaminophen.

Muscle involvement in pyruvate dehydrogenase complex (PDHC) deficiency

Muscle biopsies from a 13-month-old female infant with a delay in developmental milestones, lactic acidosis and visual disturbance, and a 6 year-old female with frequent epileptic fits are described. Biochemical studies of biopsied muscles and skin fibroblasts demonstrated markedly decreased pyruvate dehydrogenase complex (PDHC) activity to about 16% of normal value. Muscle histochemistry in both patients showed disorganized intermyofibrillar networks containing large diformazan granules on NADH-TR, small angulated fibers with high nonspecific esterase (NSE) activity and basophilic fibers. Ragged-red fibers and increased lipid droplet accumulation were absent. Patient 1 had increased numbers of type 2C fibers (11.3%) and mild fiber type grouping. On electron microscopy, most mitochondria were nearly normal. There were focal aggregates of mildly enlarged mitochondria in the subsarcolemmal areas in both patients. Morphometric study showed that the mean mitochondrial size and the mitochondrial percentage of fiber volume were not significantly different amongst patients and normal controls.

LD1 and several ratios of lactate dehydrogenase isoenzymes in acute myocardial infarction

The sensitivity and specificity of three parameters--ECG, creatine kinase MB isoenzyme and LD isoenzymes--were compared in 385 consecutive patients hospitalized for clinically suspected acute myocardial infarction (MI). In 147 patients acute MI was diagnosed on the basis of three parameters. In the remaining 238 patients acute MI was ruled out. Decision values for LD1, LD1/total LD, LD1/(LD2 + LD3 + LD4 + LD5), and the sum of LD1/LD2 + LD1/total LD + LD1/LD2 + LD3 + LD4 + LD5) were selected as 70 U/L, 0.33, 0.5, and 1.79, respectively for the test positivity of LD isoenzymes for acute MI. These new criteria, with the decision values, are proposed as test positivity of CK-MB and LD isoenzymes for acute myocardial infarction.