The Effect of Brassica Vegetable Consumption on Caffeine Metabolism in Humans

1992 ◽  
Vol 11 (3) ◽  
pp. 167-172 ◽  
Author(s):  
R.E. McDanell ◽  
L.A. Henderson ◽  
K. Russell ◽  
A.E.M. McLean
Keyword(s):  
Healthy Volunteers ◽  
Half Life ◽  
Vegetable Consumption ◽  
Interindividual Variation ◽  
Short Term ◽  
Brassica Vegetables ◽  
The Mean ◽  
Caffeine Metabolism ◽  
Brassica Vegetable ◽  
Plasma Half Life

Ten healthy volunteers were used in two studies investigating the effect of short-term Brassica consumption on caffeine metabolism. In the first study volunteers were given three Brassica-containing meals, the last one 3 h prior to caffeine administration. In the second study volunteers were given two Brassica-containing meals and then fasted overnight before caffeine administration. In both studies the mean plasma half-life of caffeine was reduced by approximately 20% following a Brassica diet, suggesting that Brassica vegetables stimulate caffeine metabolism. When caffeine was given 3 h after the last meal, plasma caffeine concentrations over 6 h, were increased by up to 27% on the Brassica diet compared to controls. This may be due to a transient increased permeability of the intestine to caffeine, immediately following Brassica consumption. This effect was not seen in the second study where there was a 12-h period between the last meal and caffeine administration. There was large interindividual variation in the effect of the Brassica diet on caffeine metabolism.

Effect of ouabain on pressor responsiveness in normal man

1994 ◽  
Vol 267 (5) ◽  
pp. E642-E647
Author(s):  
G. B. Pidgeon ◽  
A. M. Richards ◽  
M. G. Nicholls ◽  
R. R. Bailey ◽  
K. L. Lynn ◽  
...  
Keyword(s):  
Heart Rate ◽  
Healthy Volunteers ◽  
Plasma Levels ◽  
Plasma Renin ◽  
Ang Ii ◽  
Short Term ◽  
Vasoactive Hormones ◽  
Normal Man ◽  
The Mean ◽  
Mean Heart Rate

To assess the effects of ouabain on pressor and vasoactive hormone responsiveness, 10 healthy volunteers were pretreated with ouabain (0.5 mg i.v. 42 and 18 h before study) or placebo before pressor challenge with angiotensin II (ANG II; 2, 4, and 8 ng.kg-1.min-1 for 30 min/dose) and norepinephrine (NE; 5, 15, and 45 ng.kg-1.min-1 for 15 min/dose). There were no differences at baseline between the two study days regarding mean arterial pressure (MAP) or heart rate. Baseline pulse pressure, however, was significantly greater after ouabain (47 +/- 3 vs. 41 +/- 1 mmHg; P < 0.05). The mean maximum increments in MAP during ANG II and NE infusions were 17.5 +/- 1.1 and 10.5 +/- 1.3 (SE) mmHg, respectively, after ouabain and 19.2 +/- 1.3 and 10.4 +/- 1.5 mmHg after placebo (not significant). The mean heart rate was lower during both infusion periods on the ouabain study day compared with control (P < 0.05). Baseline plasma levels of ANG II, aldosterone, plasma renin activity, atrial and brain natriuretic peptide, guanosine 3',5'-cyclic monophosphate, NE, and epinephrine and achieved levels during the two infusions were similar on the two study days. We conclude that short-term ouabain administration does not alter pressor responsiveness or plasma levels of vasoactive hormones in healthy volunteers.

The Serum Half-Life and Urine Concentrations of Cephazolin Sodium in Patients with Terminal Renal Failure: Effect of Haemodialysis

1975 ◽  
Vol 20 (5) ◽  
pp. 240-243 ◽  
Author(s):  
J. B. Eastwood ◽  
P. E. Gower ◽  
J. R. Curtis
Keyword(s):  
Renal Failure ◽  
Half Life ◽  
Dosage Schedule ◽  
Dialysis Patients ◽  
Maintenance Haemodialysis ◽  
Terminal Renal Failure ◽  
Percentage Recovery ◽  
Urine Concentrations ◽  
The Mean ◽  
Plasma Half Life

The serum and plasma half-life of cephazolin has been determined in 5 maintenance haemodialysis patients during a non-dialysis period and then again in the same patients during haemodialysis with a Meltec Maxi-Multipoint dialyser using cuprophane membranes. The mean half-life during the non-dialysis period was 28.3 hours and fell to a mean of 4.97 hours during haemodialysis. Percentage recovery of cephazolin in the urine was markedly reduced in 4 maintenance dialysis patients although adequate urine concentrations of cephazolin were achieved for many sensitive organisms. A dosage schedule for patients with creatinine clearances of less than 5 ml. per minute and for maintenance haemodialysis patients is suggested.

scholarly journals Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water

2017 ◽  
Vol 75 (1) ◽  
pp. 46-51 ◽  
Author(s):  
Ying Li ◽  
Tony Fletcher ◽  
Daniel Mucs ◽  
Kristin Scott ◽  
Christian H Lindh ◽  
...  
Keyword(s):  
Drinking Water ◽  
Half Life ◽  
Perfluorooctane Sulfonate ◽  
Interindividual Variation ◽  
Serum Concentrations ◽  
Blood Samples ◽  
First Order ◽  
Contaminated Drinking Water ◽  
The Mean ◽  
Perfluorinated Alkyl Acids

BackgroundMunicipal drinking water contaminated with perfluorinated alkyl acids had been distributed to one-third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from 16 December 2013.ObjectiveTo determine the rates of decline in serum perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), and their corresponding half-lives.MethodsUp to seven blood samples were collected between June 2014 and September 2016 from 106 participants (age 4–84 years, 53% female).ResultsMedian initial serum concentrations were PFHxS, 277 ng/mL (range 12–1660); PFOS, 345 ng/mL (range 24–1500); and PFOA, 18 ng/mL (range 2.4–92). The covariate-adjusted average rates of decrease in serum were PFHxS, 13% per year (95% CI 12% to 15%); PFOS, 20% per year (95% CI 19% to 22%); and PFOA, 26% per year (95% CI 24% to 28%). The observed data are consistent with a first-order elimination model. The mean estimated half-life was 5.3 years (95% CI 4.6 to 6.0) for PFHxS, 3.4 years (95% CI 3.1 to 3.7) for PFOS and 2.7 years (95% CI 2.5 to 2.9) for PFOA. The interindividual variation of half-life was around threefold when comparing the 5th and 95th percentiles. There was a marked sex difference with more rapid elimination in women for PFHxS and PFOS, but only marginally for PFOA.ConclusionsThe estimated half-life for PFHxS was considerably longer than for PFOS and PFOA. For PFHxS and PFOS, the average half-life is shorter than the previously published estimates. For PFOA the half-life is in line with the range of published estimates.

ROLE OF THE KIDNEY IN THE METABOLISM OF LUTEINIZING HORMONE

1973 ◽  
Vol 58 (3) ◽  
pp. 425-434 ◽  
Author(s):  
D. M. de KRETSER ◽  
R. C. ATKINS ◽  
C. A. PAULSEN
Keyword(s):  
Luteinizing Hormone ◽  
Half Life ◽  
Renal Excretion ◽  
Gel Filtration ◽  
Deae Cellulose ◽  
Proximal Convoluted Tubule ◽  
Bilateral Oophorectomy ◽  
The Mean ◽  
Plasma Half Life

SUMMARY Autoradiographic localization of 125I-labelled luteinizing hormone (LH) in the renal proximal convoluted tubule of rats initiated a study of the role of the kidney in the metabolism of LH. Incubation of 131I-labelled LH with rat renal homogenates for 90 min failed to destroy its immunological reactivity. The plasma half-life of 131I-labelled LH injected i.v. was investigated in normal ewes and rams. Preliminary studies indicated that the use of a preparation containing a high proportion of 'damaged' iodinated hormone could erroneously prolong the plasma half-life. Before use, 131I-labelled LH was purified by gel filtration and column chromatography using DEAE-cellulose. The mean plasma half-life of 131I-labelled LH in normal ewes was 26·7 min and was not significantly altered after oophorectomy (31·1 min). After bilateral oophorectomy and nephrectomy, marked prolongation of the plasma half-life was observed (mean 70·7 min). In normal rams, mean plasma half-life of 131I-labelled LH was 32·0 min, after orchidectomy 44·0 min and after orchidectomy and nephrectomy 82·0 min. The plasma half-life of 131I-labelled LH in a nephrectomized ewe maintained on haemodialysis was also prolonged (67·5 min), the determination being performed 24 h after the last haemodialysis. Although the kidney does not degrade LH, the plasma half-life was significantly increased after nephrectomy. This suggests that the localization of 125I-labelled LH in the proximal convoluted tubule may represent a secretory mechanism allowing renal excretion of LH.

Drug Interaction between Rifampicin and Cotrimoxazole in Patients with Tuberculosis

1991 ◽  
Vol 10 (6) ◽  
pp. 419-421 ◽  
Author(s):  
R.S. Bhatia ◽  
R. Uppal ◽  
R. Malhi ◽  
D. Behera ◽  
S.K. Jindal
Keyword(s):  
Drug Interaction ◽  
Half Life ◽  
Serum Levels ◽  
Antitubercular Therapy ◽  
The Mean ◽  
Plasma Half Life

1 Patients ( n = 15) who were admitted with complications of tuberculosis, were given antitubercular therapy (ATT) with rifampicin (RIF), for a minumum period of 15 d, and cotrimoxazole (CTZ), concurrently, for 5-10 d. 2 The serum RIF levels were measured before the start of CTZ treatment and at the end of its administration. 3 The plasma half-life ( t½) of RIF increased significantly from 1.92 ± 0.57 h to 2.31 ± 0.134 h after CTZ treatment. 4 The mean serum levels of RIF increased significantly at 4 and 6 h after CTZ administration.

Gas chromatographic assessment of the reproducibility of phenazone plasma half-life in young healthy volunteers

1974 ◽  
Vol 7 (5) ◽  
pp. 381-385 ◽  
Author(s):  
S. Lindgren ◽  
P. Collste ◽  
B. Norlander ◽  
F. Sj�qvist
Keyword(s):  
Healthy Volunteers ◽  
Half Life ◽  
Plasma Half Life

scholarly journals Influence of maturation and growth on cefetamet pivoxil pharmacokinetics: rational dosing for infants.

1996 ◽  
Vol 40 (3) ◽  
pp. 567-574 ◽  
Author(s):  
W L Hayton ◽  
J Kneer ◽  
R de Groot ◽  
K Stoeckel
Keyword(s):  
Body Weight ◽  
Half Life ◽  
Pediatric Patients ◽  
Volume Of Distribution ◽  
Systemic Clearance ◽  
Older Children ◽  
Dosing Regimen ◽  
Urinary Recovery ◽  
The Mean ◽  
Plasma Half Life

The pharmacokinetics of intravenous (i.v.) cefetamet and the bioavailability of oral cefetamet pivoxil in infants aged 3.5 to 17.3 months who were hospitalized for urological surgery were characterized. The absorption of cefetamet pivoxil administered in a syrup formulation was 38 +/- 19% (n = 5) for infants, which was comparable to values observed for children and adults. The plasma half-life of i.v. cefetamet was 3.03 +/- 0.96 h (mean +/- standard deviation; n = 20) in the infants. This was not different from the value observed for normal adult subjects but was longer than that reported for children aged 3 to 12 years. Urinary recovery of cefetamet after i.v. administration to infants was 63.4 +/- 17.7% (n = 16), which was less than the 80% recovery found in older children and adults. The steady-state volume of distribution was 399 +/- 116 ml/kg of body weight. It was comparable in size and showed the same dependence on body weight as it did in children and adults. The mean systemic clearance per kilogram of body weight in the infants was lower than that in children and adults, apparently because of immaturity of clearance processes. A model that accounted for maturation and growth with increasing age was developed for the clearance. On the basis of this model, the clearance capacity increased from birth to 5 years by a factor of 4.5 because of maturation. Maturation progressed exponentially, with a half-life of 14 months. This model was used to develop dosing regimen guidelines for pediatric patients aged 3.5 months and older.

scholarly journals Population pharmacokinetic study of isepamicin with intensive care unit patients.

1996 ◽  
Vol 40 (4) ◽  
pp. 983-987 ◽  
Author(s):  
M Tod ◽  
C Padoin ◽  
C Minozzi ◽  
J Cougnard ◽  
O Petitjean
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Healthy Volunteers ◽  
Half Life ◽  
Volume Of Distribution ◽  
Multivariate Linear Regression Analysis ◽  
Icu Patients ◽  
Elimination Half Life ◽  
Elimination Half ◽  
The Mean

The pharmacokinetics (PK) of isepamicin, a new aminoglycoside, were studied in 85 intensive care unit (ICU) patients and were compared with those observed in 10 healthy volunteers. A parametric method based on a nonlinear mixed-effect model was used to assess population PK. Isepamicin was given intravenously over 0.5 h at dosages of 15 mg/kg once daily or 7.5 mg/kg twice daily. The data were fitted to a bicompartmental open model. Compared with healthy volunteers, the mean values of the PK parameters were profoundly modified in ICU patients: elimination clearance was reduced by 48%, the volume of distribution in the central compartment (Vc) was increased by 50%, the peripheral volume of distribution was 70% higher, the distribution clearance was 146% lower, and the elimination half-life was ca. 3.4 times higher. The interindividual variability in PK parameters was about 50% in ICU patients. Five covariates (body weight [BW], simplified acute physiology score [SAPS], temperature, serum creatinine level, and creatinine clearance [CLCR]) were tentatively correlated with PK parameters by multivariate linear regression analysis with stepwise addition and deletion. The variability of isepamicin clearance was explained by three covariates (BW, SAPS, and CLCR), that of Vc was explained by BW and SAPS, and that of the elimination half-life was explained by CLCR and SAPS. Simulation of the concentration-versus-time profile for 500 individuals showed that the mean peak (0.75 h) concentration was 18% lower in ICU patients than in healthy volunteers and that the range in ICU patients was very broad (28.4 to 95.4 mg/liter). Therefore, monitoring of the isepamicin concentration is in ICU patients is mandatory.

Increased Antipyrine Half-Life in Women Taking Oral Contraceptives

1970 ◽  
Vol 15 (12) ◽  
pp. 454-456 ◽  
Author(s):  
K. O'Malley ◽  
I. H. Stevenson ◽  
Wilma Alexander
Keyword(s):  
Oral Contraceptive ◽  
Oral Contraceptives ◽  
Half Life ◽  
Control Value ◽  
Control Subjects ◽  
The Mean ◽  
Plasma Half Life

The plasma half-life of antipyrine has been measured in 18 women taking oral contraceptives and in 19 control subjects. The mean half-life in the oral contraceptive group of 13.2±2.0 hr. was significantly prolonged compared to the control value of 10.5±2.5 hours

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