Association among 1267 A/G HSP70-2, -308 G/A TNF-α polymorphisms and pro-inflammatory plasma mediators in old ZincAge population.

Proinflammatory cytokines and heat shock proteins play relevant roles in the pathogenesis of inflammatory diseases. We investigated whether Hsp70 1267 A/G and TNF-α -308 G/A polymorphisms are associated with proinflammatory mediators, zinc status and laboratory parameters in 1,078 healthy elderly from ZincAge study. Hsp70 1267 A/G genotype and allele distribution were similar among various European countries, while a TNF-α genetic heterogeneity was observed between the Northern and the Southern European populations, with a major frequency of the -308 A variant in France, Germany and Poland. We used linear regression models to test additive, dominant or recessive associations of each SNP with proinflammatory mediators, laboratory parameters, metallothioneins and zinc status. Hsp70 1267 A/G SNP, but not TNF-α -308 G/A SNP, influences TNF-α and IL-6 plasma levels under additive, dominant and recessive models (for TNF-α only). An association between Hsp70 1267 A/G SNP and zinc plasma levels was observed in the dominant model. In particular, G allele carriers showed increased circulating pro-inflammatory cytokines and zinc. Moreover, both these SNPs affect creatinine levels suggesting a possible influence on renal function. In conclusion, Hsp70 1267 A/G SNP is associated with pro-inflammatory cytokine production in healthy elderly and might represent a possible determinant of individual susceptibility to inflammatory diseases.

Acetylcholinesterase inhibitors in Alzheimer's disease influence Zinc and Copper homeostasis.

BACKGROUND: Alzheimer's disease (AD) is the most common age-related neurodegenerative disease. An altered homeostasis of Zinc (Zn) and Copper (Cu), as well as a dysregulated expression of Zn-regulatory proteins have been previously described in AD. Acetylcholinesterase inhibitors (AChEI) are commonly used as AD treatment to improve cognitive function, but their effect on Zn homeostasis is still unexplored. OBJECTIVES: The aims of this study were to define the metal dyshomeostasis in AD patients, to investigate AChEI influence on Zn homeostasis and inflammation, and to analyze the relationship between cognitive impairment at two-year follow-up and metal concentrations, considering AChEI use. METHODS AND RESULTS: 84 Healthy Elderly (HE) and 95 AD patients were enrolled (62 AchEI user and 33 AchEI naïve). HE showed similar plasma Zn and Cu concentrations and Cu/Zn ratio in comparison to AChEI users, but significantly higher Zn level, as well as lower Cu amount and Cu/Zn ratio than AChEI naïve patients. Moreover, AChEI users had increased Zn plasma level, reduced Cu amount, Cu/Zn ratio, and IL1ß concentration and lower Zip2 lymphocytic expression vs. naïve patients. A multiple linear regression analysis showed that the MMSE score decline after two-year follow-up was reduced by AChEI therapy and was positively associated with plasma Zn decrease over time. CONCLUSION: Our data revealed that AChEI use may affect peripheral Zn and Cu homeostasis in AD patients, decrease Cu/Zn ratio demonstrating a general reduction of inflammatory status in patients under AChEI treatment. Finally, AChEI influence on circulating Zn could be implicated in the drug-related slowdown of cognitive decline.

Synthesis of a versatile constrained analogue of dipeptide DG (Asp-Gly).

The synthesis of an orthogonally protected constrained analogue of dipeptide DG (Asp-Gly) is reported exploiting alkylation of a chiral lactam. The versatility of this analogue was proven by removal of t-Boc protecting group, followed by coupling under homogeneous conditions with t-Boc-Arg(Z(2))-Gly, to give a conformationally restricted analogue of RGDG tetrapeptide.

Catalytic mechanism of l,l-diaminopimelic acid with diaminopimelate epimerase by molecular docking simulations.

Peptidoglycan, a key constituent of bacterial cell walls, is currently the target of broad spectrum antibiotics and a new research field involves both design and synthesis of inhibitors of its biosynthesis. Most bacteria require either lysine, or its biosynthetic precursor, diaminopimelate (meso-DAP), as a component of the peptidoglycan layer of the cell wall. In this paper, molecular modelling studies were undertaken in order to shed light on the molecular basis of interaction between (2S,6S)-diaminopimelic acid (l,l-DAP) (1) with its target enzyme DAP-epimerase, since this is a key step in the lysine biosynthetic path leading to (2R,6S)-diaminopimelic acid (meso-DAP) (2). In particular, the docking of the ligand-enzyme complex was studied by means of MD simulations and DFT computations in order to ascertain the optimal structural requirements for the epimerization reaction. Molecular dynamics simulations clearly showed that the configuration of the distal carbon C6 of l,l-DAP is critical for complex formation since both amino and carboxylate groups are involved in Hbonding interactions with the active site residues. Furthermore, the interactions occurring between the functional groups bonded to the C2 and some residues of the binding cavity immobilize the ligand in a position appropriate for the epimerization reaction, i.e., exactly in the middle of the two catalytic residues Cys73 and Cys217 as confirmed by DFT quantum mechanical computation of the Michaelis complex. All this mechanistic information could be useful for the rational design of new potential antibiotic drugs effective as inhibitors of peptidoglycan biosynthesis.

ZnT8 Arg325Trp polymorphism influences zinc transporter expression and cytokine production in PBMCs from patients with diabetes.

AIMS: ZnT8 Arg325Trp polymorphism has been associated with type 2 diabetes (T2DM) susceptibility. The Arg-325 risk variant shows accelerated zinc (Zn) transport kinetic and reduced glucose-stimulated insulin secretion in pancreatic cells. However, it remains unexplored the role of Znt8 polymorphism in the regulation of Zn homeostasis and inflammatory response in peripheral blood mononuclear cells (PBMCs) from T2DM patients. METHODS AND RESULTS: A total of 556 healthy controls and 413 T2DM patients were genotyped for ZnT8 Arg325Trp polymorphism confirming the association of Arg-325 variant with an increased T2DM risk (OR = 1.35 95% C.I: 1.10-1.66; p = 0.0044). Moreover, PBMCs from Arg/Arg T2DM subjects showed increased intracellular free Zn, higher gene expression of Metallothioneins, Znt1, Znt8, Zip2 genes, and reduced Znt4 and Znt7. Higher release of IL-1α, IL-1ß, IFN-γ, IL-12p70 and TNF-α and a reduced IL-10 secretion after lipopolysaccharide (LPS) stimulation were observed in PBMCs from Arg/Arg T2DM carriers as compared to subjects with the Trp variant. CONCLUSIONS: Our data provide evidence of a substantial different Zn homeostasis regulation between Znt8 Arg-325 and Trp-325 carriers in PBMCs from T2DM patients. Moreover, Znt8 Arg-325 risk variant shows an enhanced inflammatory response upon LPS stimulation that might aggravate insulin resistance and the progression of diabetes cardiovascular complications.

Physicochemical conditions for ZnO films deposited by microwave chemical bath deposition.

Physicochemical analysis was carried out to obtain the species distribution diagrams (SDDs) for the deposition of ZnO films as a function of OH- ion concentration ([OH-]) in the reaction solution. The study of SDDs predicts nucleation and ZnO film growth by means of the dominant species at a given pH value. To confirm this, a series of experiments were made varying the [OH-] in the reaction solution and keeping the others parameters constant. Structured zinc oxide (ZnO) films were obtained on glass substrates by microwave chemical bath deposition (MWCBD). Structural, optical and morphological ZnO film properties were investigated as a function of [OH-]. X-Ray diffraction technique (XRD) measurements show multiple diffraction peaks, indicating the polycrystalline nature of ZnO films. Scanning Electron Microscopy (SEM) images of ZnO structures showed morphological changes with the variation of [OH-]. The stoichiometry of the structures changed as the [OH-] was varied in solution. From Raman spectra, it was observed that the [OH-] of the reaction mixture strongly affects the crystal quality of ZnO structures. A reaction pathway for the synthesis of ZnO structures based on our results is proposed. Experimental results are consistent with the physical-chemical analysis.

Bile acid excretion: the alternate pathway in the hamster.

The quantitative significance of renal excretion of bile acid ester sulfates as an alternate excretory pathway was evaluated in hamsters. After bile duct ligation, total serum bile acid fell from a mean level of 454 microgram/ml at 24 h to 64 microgram/ml by 96 h. During this period the bulk of the bile acid pool could be accounted for as esterified bile acids in urine. Renal pedicle ligation of animals with bile duct obstruction led to retention of the bile acid ester sulfates in serum. Thioacetamide hepatotoxicity diminished ester sulfation of bile acids causing diminished renal secretion with relatively greater retention of nonesterified bile acids in serum. We conclude that secretion of esterified bile acids by the kidney is an efficient alternate pathway for maintaining bile acid excretion in obstructive biliary tract disease. Coexistent hepatocellular disease diminishes ester sulfation and the effectiveness of the alternate pathway in maintaining bile acid excretion.

The inflammation-sensitive protein alpha 1-anti-chymotrypsin neutralizes fibrillar aggregation and cytotoxicity of the beta-amyloid peptide more effectively than alpha 1-antitrypsin.

OBJECTIVES: A neuroinflammatory process, triggered by amyloid-beta (Abeta)-peptide, is thought to play a central role in the neurodegenerative process leading to Alzheimer's disease (AD). Abeta(25-35) retains the functionality of Abeta(42) and was employed to investigate the effects of inflammation-sensitive proteins (ISPs) alpha1-antichymotrypsin (A1ACT) and alpha1-antitrypsin (A1AT) on fibrillar aggregation and cytotoxicity. DESIGN AND METHODS: Inhibitory concentrations of the ISPs were determined in an established human red blood cell lysis model of Abeta-cytotoxicity. For studies of Abeta-fibrillar aggregation CSF levels of A1ACT (0.041 microM)/A1AT (0.11 microM) were incubated with Congo Red dye 25 microM+Abeta(25-35) 10 microM noting the formation of visible aggregates and spectrophotometric changes over 24 h. RESULTS: A1ACT at CSF reported levels inhibited fibrillar aggregation and cytotoxicity while A1AT at CSF reported levels failed to cause a similar inhibition. CONCLUSIONS: A1ACT neutralizes fibrillar aggregation and cytotoxicity of Abeta-peptide more effectively than A1AT. Both proteins are known to be co-deposited with Abeta within senile plaques of AD brains.

Oral ulcer by Sphingomonas paucimobilis: first report.

The first case of an oral infection caused by Sphingomonas paucimobilis is reported. A 73-year-old man presented with a gingival ulcer with bone exposure affecting the attached gingiva in the anterior maxillary region. He reported pain during chewing and the presence of fever. Since the first case of S. paucimobilis infection was reported in 1977, involving a leg ulcer, the number of reports related to this organism has been increasing, indicating that the bacterium should be considered an emerging pathogen. It is possible that other non-classical pathogens of the oral cavity may be responsible for infectious lesions, which represents a diagnostic and therapeutic challenge.

Selective zircon accumulation in a new benthic foraminifer, Psammophaga zirconia, sp. nov.

Benthic foraminifera are single-celled eukaryotes that make a protective organic, agglutinated or calcareous test. Some agglutinated, single-chambered taxa, including Psammophaga Arnold, 1982, retain mineral particles in their cytoplasm, but the selective mechanism of accumulation is not clear. Here, we report the ability of a foraminiferal species to select and accumulate zircons and other heavy minerals in their cytoplasm. In particular, the use of Scanning Electron Microscope coupled with an Energy Dispersive X-ray microanalysis system (SEM-EDS) enabled a representative overview of the mineral diversity and showed that the analysed Psammophaga zirconia sp. nov. individuals contained dominantly crystals of zircon (51%), titanium oxides (27%), and ilmenite (11%) along with minor magnetite and other minerals. The studied specimens occur in the shallow central Adriatic Sea where the sediment has a content of zircon below 1% and of other heavy minerals below 4%. For that reason we hypothesize that: (i) P. zirconia may be able to chemically select minerals, specifically zircon and rutile; (ii) the chemical mechanism allowing the selection is based on electrostatic interaction, and it could work also for agglutinated foraminifera (whether for ingestion, like Xenophyophores, or incorporation in the test as in many other described taxa). In particular, this aptitude for high preferential uptake and differential ingestion or retention of zircon is reported here for the first time, together with the selection of other heavy minerals already described in members of the genus Psammophaga. They are generally counted among early foraminifera, constructing a morphologically simple test with a single chamber. Our molecular phylogenetic study confirms that P. zirconia is a new species, genetically distinctive from other Psammophaga, and occurs in the Adriatic as well as in the Black Sea.

Transthyretin inhibition of amyloid beta aggregation and toxicity.

OBJECTIVES: The aim of this study was to investigate transthyretin (prealbumin) effects on Abeta25-35-induced cytotoxicity. DESIGN AND METHODS: In view of the well-recognized literature data demonstrating that Abeta25-35 fibrillar aggregates cause in vitro cytotoxicity to human red blood cells and apoptotic changes to SK-N-BE neuroblastoma cells in cultures (ultrastructural evidence), we tested transthyretin effects on these two experimental models. RESULTS: Incubation of Abeta25-35 with transthyretin (at transthyretin concentrations equal to CSF physiological levels) demonstrated both inhibition of red blood cells lysis and neutralization of SK-N-BE neuroblastoma cells ultrastructural apoptotic changes. Moreover, transthyretin was shown to be able to inhibit the formation of fibrillar macroaggregates of Abeta25-35. CONCLUSIONS: The findings imply that experimental systems investigating Abeta-induced cytotoxicity consider the protective interaction of transthyretin with Abeta; an interaction to be considered also in vivo in view of the fact that transthyretin immunoreactivity has been previously demonstrated in amyloid plaques of brains from Alzheimer's disease patients.

Gastric emptying and intragastric balloon in obese patients.

BACKGROUND: Intragastric balloons have been proposed to induce weight loss in obese subjects. The consequences of the balloon on gastric physiology remain poorly studied. We studied the influence of an intragastric balloon on gastric emptying in obese patients. PATIENTS AND METHODS: 12 patients were included in the study, with BMI (mean +/- SD) of 38.51 +/- 4.32 kg/m2. The balloon was inserted under light anaesthesia and endoscopic control, inflated with 700 ml saline, and removed 6 months later. Body weight and gastric emptying (T1/2 and T lag) using 13C-octanoic acid breath test were monitored before balloon placement, during its permanence and 2 months after removal. RESULTS: Mean weight loss was: 6.2 +/- 2.3 kg after one month; 12.4 +/- 5.8 kg after 3 months; 14.4 +/- 6.6 kg after 6 months and 10.1 +/- 4.3 kg two months after BIB removal. Gastric emptying rates were significantly decreased in the first periods with balloon in place, and returned to pre-implantation values after balloon removal. T1/2 was: 87 +/- 32 min before BIB positioning, 181 +/- 91 min after 1 month, 145 +/- 99 min after 3 months, 104 +/- 50 min after 6 months and 90 +/- 43 min 2 months after removal. T lag was 36 +/- 18 min before BIB positioning, 102 +/- 82 min after 1 month, 77 +/- 53 min after 3 months, 59 +/- 28 min after 6 months and 40 +/- 21 min. 2 months after removal. CONCLUSIONS: BIB in obese patients seems to be a good help in following the hypo caloric diet, especially during the first three months when the gastric emptying is slower and the sense of repletion is higher. After this period gastric emptying starts to return to normal and the stomach adapts to BIB loosing efficacy in weight loss.

The metabolism of 3,3'-diiodothyronine in man.

The production rate of 3,3'-Diiodothyronine (3,3'-T2) was measured in five healthy subjects after a single injection of [125I]3,3'-T2. The [125I]3,3'-T2 was measured by immunoprecipitation. To reduce the large amount of nonspecific serum radioactivity (iodides, 3,3'-T2 metabolites, and protein-bound iodine), the sear were treated before the immunoprecipitation with an anion exchanger and polyethylene glycol (final concentration, 10%). The noncompartmental analysis of the data gave the following results: MCR, 0.52 +/- 0.07 liters/min or 926 +/- 142 liters/day (mean +/- SD); and production rate, 23.7 +/- 8.2 ng/min or 34 +/- 12 micrograms/day.

Isosorbide dinitrate bioavailability, kinetics, and metabolism.

We studied the kinetics of isosorbide dinitrate (ISDN) after a dose of 5 mg iv and the bioavailability of a sublingual and an oral preparation of ISDN. Plasma levels of isosorbide 5-mononitrate (IS-5-MN), isosorbide 2-mononitrate (IS-2-MN), and ISDN were determined by GLC. After intravenous and sublingual dosing, ISDN plasma levels declined biexponentially and could adequately be described by an open two-compartment body model. Distribution was rapid; the t1/2 was 4.7 minutes after intravenous injection and 8.7 minutes after sublingual dosing. The volume of distribution at steady state was 90 L. The terminal disappearance t1/2 was 54.7 minutes after intravenous injection, 48.8 minutes after sublingual dosing, and 47.7 minutes after oral dosing. Total plasma clearance was 136 L/hr, exceeding normal liver plasma flow and indicating extrahepatic metabolism of ISDN. ISDN bioavailability after oral (10 mg) or sublingual dosing (10 mg) was similar (about 29%), indicating that the first-pass effect cannot be avoided by sublingual ISDN dosing. After intravenous ISDN, mononitrate plasma levels could be adequately described by another two-compartment body model. The terminal t1/2 was 4.33 hours for IS-5-MN and 1.83 hours for IS-2-MN. Noncompartmental calculations of the mononitrate levels revealed 100% systemic availability after oral and sublingual ISDN. We assume that ISDN was completely absorbed from the gastrointestinal tract, but 70% was metabolized during the first pass through the liver. After 5 mg iv ISDN, 16 mumol IS-5-MN and 5.3 mumol IS-2-MN reached systemic circulation. The entire dose of ISDN was converted to its two metabolites in a ratio of 3:1 (i.e., 75% IS-5-MN and 25% IS-2-MN).

N-Acetyl-procainamide kinetics in the elderly.

Plasma and saliva N-acetyl-procainamide (NAPA) concentrations were measured by high-power liquid chromatography (HPLC) after intravenous infusion of 750 mg to 14 elderly patients (x age = 69 yr). The plasma NAPA disappearance curve can best be described by a two-compartment body model. Mean total body clearance was 10.6 1/hr, Vdss 125.8 1, and terminal half-life (t 1/2) 8.8 hr. A nonrenal clearance of 2.72 1/hr was calculated, that is, 19% of the expected total body clearance with normal kidney function. Saliva concentrations show huge inter- and intraindividual variability and are probably not usable for NAPA monitoring in older patients.

Constant kinetics and constant concentration-effect relationship during long-term beta-blockade with pindolol.

Long-term beta-blockade is said to increase the number of beta-receptors. The effect of beta-blockers could therefore be reduced after long use. We tested this hypothesis in nine healthy subjects given 15 mg pindolol daily for 4 wk. Plasma concentrations (measured fluorometrically), isoproterenol dose-response relationship (to calculate the dose needed to increase heart rate by 25 bpm), renin, epinephrine, and norepinephrine were measured several times before and after the first and last dose. Kinetic parameters remained stable: total clearance (Cltot) = 45.2 and 42.9 l/hr, and Vdss = 205.8 and 198.6 l after the first and last dose. The concentration-effect relationship, plotted as the "dose ratio minus one" against the log of the plasma concentration was identical after 4 wk. Basal plasma renin activity was reduced slightly and the increase of stimulated plasma renin was blunted by pindolol even after 4 wk. The initial lowering of unstimulated renin by pindolol in the first 2 hr after dosing was not detectable after 4 wk. Epinephrine and norepinephrine levels in plasma were not changed initially nor after 4 wk. It is concluded that pindolol has a stable kinetic profile over time and that its beta-blockade does not induce tachyphylaxis.

Isosorbide 5-mononitrate and isosorbide 2-mononitrate kinetics after intravenous and oral dosing.

Isosorbide 5-mononitrate (IS-5-MN) and isosorbide 2-mononitrate (IS-2-MN) kinetics were studied in two groups of young healthy subjects after intravenous injection of 5 mg of both and after oral doses of 20 mg of IS-2-MN and 10, 15, and 20 mg of IS-5-MN. Mononitrate plasma levels were measured by GLC with capillary columns. After intravenous injection, IS-5-MN and IS-2-MN plasma levels declined biexponentially and could be described by an open two-compartment body model. Distribution t 1/2 was rapid; 8.6 min for IS-5-MN and 12.5 min for IS-2-MN. Substances were distributed throughout body water; volume of distribution at steady state (Vd ss) was 48 l for IS-5-MN and 55 l for IS-2-MN and elimination t 1/2 was 4.15 hr for IS-5-MN and 1.9 hr for IS-2-MN. Total plasma clearance was 8.5 l/hr for IS-5-MN and 23.2 l/hr for IS-2-MN. After oral doses the mononitrates were rapidly and completely absorbed (absorption t 1/2 ranged from 2.5 to 5 min) from the gastrointestinal tract without first-pass metabolism, i.e., absolute systemic availability was 100%. In the dose range studied, kinetics of the two mononitrates were linear. Compared with isosorbide dinitrate, mononitrate kinetics are different because of greater systemic availability, slower clearance, and smaller Vd ss.

The renal elimination of procainamide.

The question of pH or flow dependence for the renal elimination of procainamide (PCA) was studied under 4 conditions in each of 4 subjects. Each subject received 500 mg of PCA intravenously at weekly intervals while in a state of (1) acid load (NH4Cl) and water deprivation, (2) acid load and water excess, (3) alkali load (NaHCO3) and water deprivation, and (4) alkali load and water excess. Plasma and urine were collected at frequent intervals for PCA and N-acetyl PCA (NAPA) analysis. Urine flow rates varied markedly between the water deprivation and water excess states (approximately 1.2 vs 5 ml/min, respectively), and urine pH varied markedly between the acid and alkali load states (pH = ca 5 vs 8, respectively). Despite this marked variation, there were no significant changes in PCA renal clearance or 24-hr PCA or NAPA excretion. If passive diffusion of PCA were taking place, such flow and pH changes would have caused marked changes in PCA clearance were the pH partition hypothesis true. We therefore conclude that passive diffusion is not an important mechanism in the renal elimination of PCA in man and that there must be tubular secretion. The implication for the clinical use of the drug is that dose adjustments need not be made in response to variations in urine flow and pH.

Effects of the calcium antagonist tiapamil on pulmonary gas exchange in patients with chronic obstructive pulmonary disease who receive salbutamol.

Patients with chronic obstructive pulmonary disease (COPD) and cardiovascular diseases are frequently given combination therapy with a beta 2-agonist and a calcium antagonist. Each drug is known to increase ventilation-perfusion inequalities. It was our aim to define the effects of their combination on lung function and on pulmonary gas exchange in eight subjects with COPD but partially reversible airway obstruction. Sixty minutes after placebo or 450 mg tiapamil, subjects inhaled 0.2 mg salbutamol. There was no significant effect of tiapamil on specific airway conductance and the forced expiratory volume in 1 second before or after the inhalation of salbutamol. Blood was drawn 30, 55, 80, and 100 minutes after placebo or tiapamil dosing. After placebo the mean (+/- SD) arterial oxygen tension (Pao2) fell from 67.1 +/- 7.3 to 64.4 +/- 5.5 mm Hg and the mean alveolar-arterial oxygen tension difference (AaDo2) rose from 34.6 +/- 8.4 to 40.5 +/- 6.8 mm Hg. After tiapamil the mean Pao2 fell from 68.7 +/- 7.3 to 66.4 +/- 5.8 mm Hg and the mean AaDo2 rose from 35.1 +/- 6.8 to 38.7 +/- 7.4 mm Hg. The changes in Pao2 were not significant. The increase in AaDo2 after placebo was significant, but that after tiapamil was not. We conclude that the combination of the calcium antagonist tiapamil and the bronchodilator salbutamol is safe with respect to lung function in COPD. There is no evidence that tiapamil increases beta 2-agonist-induced impairment in pulmonary gas exchange.

Relationship between the pharmacokinetics and pharmacodynamics of procainamide.

The kinetics of a measure of pharmcologic effect (prolongation of the QT interval) of procainamide, as well as the kinetics of the plasma concentration, urine excretion, and saliva concentration of the drug were investigated in 14 trials in 4 subjects. A single 500-mg dose was given by rapid intravenous infusion, and frequent subsequent determinations of the above variables were made. A 2-compartment pharmacokinetic model with a third compartment for the saliva was used to fit the plasma, urine, and saliva data simultaneously. Analysis of the data reveals that the kinetics of the drug concentrations in saliva and of the pharmacologic effect are indistinguishable. They both must be considered to be different from those of the drug concentrations in plasma. Thus, in normal individuals under the conditions of this study, saliva concentrations more precisely indicate the time-course of drug at a cardiac site of action, although they do not parallel plasma drug concentrations until 6 hr or more after a rapid intravenous infusion. The following average pharmacokinetic parameters for plasma were found: terminal half-life, 2.9 hr; total clearance, 828 ml/min; renal clearance, 334 ml/min; and steady-state volume of distribution, 180 L. Average distribution pseudoequilbrium half-time (t1/2 alpha) was 5.2 min from an initial volume of distribution of 36.6 L.