scholarly journals Hydroxocobalamin

Blood ◽  
1966 ◽  
Vol 27 (2) ◽  
pp. 227-233 ◽  
Author(s):  
GEORGE B. JERZY GLASS ◽  
DUK HO LEE
Keyword(s):  
Intravenous Injection ◽  
Half Life ◽  
Intramuscular Injection ◽  
Human Subjects ◽  
Biological Half Life ◽  
Double Label ◽  
Normal Human ◽  
The Mean

Abstract The mean hepatic biological half-life of Co57-hydroxocobalamin injected to 5 normal human subjects was similar to that of Co60-cyanocobalamin, as shown by double-label hepatic surface counting during the first 30 weeks after intramuscular or intravenous injection of cobalamins. In 2 cases in whom the counting was extended over a year’s period, the clearance of hepatic radioactivity following the intramuscular injection of hydroxocobalamin has slowed down as compared to that of cyanocobalamin, between the 30th and 52nd week after injection.

URINARY EXCRETION OF ANDROST-16-EN-3α-OL LEVELS IN NORMAL SUBJECTS, AND EFFECTS OF TREATMENT WITH TROPHIC HORMONES

1962 ◽  
Vol 24 (4) ◽  
pp. 435-444 ◽  
Author(s):  
B. W. L. BROOKSBANK
Keyword(s):  
Menstrual Cycle ◽  
Urinary Excretion ◽  
Small Proportion ◽  
Intramuscular Injection ◽  
Human Subjects ◽  
Normal Subjects ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Normal Human ◽  
The Mean

SUMMARY Data are presented on the urinary excretion of androst-16-en-3α-ol by normal human subjects over the age span 4–86 years. The figures range from < 100 to 2630 μg./24 hr. in males, and < 100 to 1100 μg./24 hr. in females, the mean for men of 16–45 years being nearly three times that for women of the same age. The effect on urinary androstenol and 17-oxosteroids of human chorionic gonadotrophin (HCG) and of corticotrophin (ACTH) have been compared in three normal young men and two women. Marked elevation of androstenol excretion occurred after ACTH in both sexes, while HCG administration resulted in an increased urinary output of androstenol and 17-oxosteroids only in two of the men and not in the women tested in either phase of the menstrual cycle. Intramuscular injection of androstenol itself (20 mg.) resulted in increased levels of androstenol in the urine equivalent only to a very small proportion of the injected dose. The metabolic origin of androstenol is discussed in the light of the results presented and of those of other investigators. It seems likely that androstenol arises not primarily from testosterone but mainly from an adrenal precursor.

Pharmacokinetics and Tissue Residues of Sulfathiazole and Sulfamethazine in Pigs

1994 ◽  
Vol 57 (9) ◽  
pp. 796-801 ◽  
Author(s):  
LIEVE S. G. VAN POUCKE ◽  
CARLOS H. VAN PETEGHEM
Keyword(s):  
Intravenous Injection ◽  
Half Life ◽  
Intramuscular Injection ◽  
Compartment Model ◽  
Absolute Bioavailability ◽  
Pharmacokinetic Parameters ◽  
Tissue Concentrations ◽  
Single Intravenous Injection ◽  
The Individual ◽  
Residue Study

The plasma pharmacokinetics and tissue penetration of sulfathiazole (ST) and sulfamethazine (SM) after intravenous and intramuscular injection in pigs were studied. Following a single intravenous dose of 40 mg ST/kg of bodyweight or 80 mg SM/kg of bodyweight, the plasma ST and SM concentrations were best fitted to a two-compartment model. The areas under the curve were 447 ± 39 and 1485 ± 41 mg/h/L, clearances were 0.090 ± 0.007 and 0.054 ± 0.001 L/kg/h, volumes of distribution were 1.16 ± 0.16 and 0.77 ± 0.06 L/kg, half-lifes in distribution phase were l.18 ± 0.57 and 0.23 ± 0.16 h and half-lifes in eliminations phase were 9.0 ± l.6 and 9.8 ± 0.6 h. When the two compounds were administered simultaneously as a single intravenous injection, the pharmacokinetic parameters for ST were not significantly different. The values for SM show statistical differences for some important parameters: α, β and the AUC0–&gt;∞ were significantly decreased and t1/2α, Vd and CIB were significantly increased. It can be concluded that after a single intravenous injection of 40 mg/kg, sulfathiazole has a high tl/2β resulting in higher tissue concentrations. This half-life, which is higher than what is reported in the literature, is not influenced by the simultaneous presence of sulfamethazine. The tl/2β for sulfamethazine after a single intravenous injection of 80 mg/kg is comparable to the data from the literature and is not influenced by the presence of sulfathiazole. Sulfathiazole and SM were also administered simultaneously as an intramuscular injection to healthy pigs at a dosage of 40 and 80 mg/kg bodyweight. Pharmacokinetic experiments were conducted on three pigs. From this pharmacokinetic study it can be concluded that upon a single intramuscular administration of 40 mg/kg of ST and 80 mg/kg of SM the absolute bioavailability in pigs is 0.92 ± 0.04 for ST and l.01 ± 0.07 for SM. Six pigs received five intramuscular im) injections as a single dose of ST and SM every 24 h for five consecutive days for the residue study. The pigs were slaughtered at different times after the last dose was given and samples were taken from various tissues and organs. Concentrations were determined by a microbiological method and a HPTLC method. No edible tissue contained more than 100 μg/kg of the individual sulfonamides after 10 days of withdrawal. It means that adult animals which have a shorter half-life and thus lower tissue concentrations will certainly meet the economic community EC) maximum residue limits after a 10 days withdrawal period.

METABOLISM OF [4-14C]LYNESTRENOL IN MAN

1968 ◽  
Vol 42 (2) ◽  
pp. 337-343 ◽  
Author(s):  
SORAYA KAMYAB ◽  
K. FOTHERBY ◽  
A. I. KLOPPER
Keyword(s):  
Phenolic Compounds ◽  
Enzymatic Hydrolysis ◽  
Half Life ◽  
Human Subjects ◽  
Free Fraction ◽  
Urinary Metabolites ◽  
Polar Compounds ◽  
Mean Value ◽  
Biological Half Life ◽  
Chromatographic Evidence

SUMMARY After the administration of [4-14C]lynestrenol (17α-ethynyl-19-nor-androst-4-en-17β-ol) to 7 human subjects 31·–57·6% of the dose, whether administered orally or i.v., was excreted in the urine within 5 days. The biological half-life of radioactivity was 26·5 hr. After acid and enzymatic hydrolysis, 58·7 and 45·6% respectively of the urinary radioactivity was extractable. About 10% of the urinary metabolites were excreted as sulphate conjugates. A mean value of 1·75% of the administered dose was converted to phenolic compounds. The metabolites in the free fraction and enzymehydrolysed extract of urine were almost entirely polar compounds, whereas 70% of the metabolites in the sulphate fraction were much less polar. The chromatographic evidence showed that hydroxylation of lynestrenol must have occurred at two points in the molecule. Plasma radioactivity decreased more rapidly than after administration of norethisterone.

Catechol O-Methyltransferase in Red Blood Cells of Schizophrenic, Depressed, and Normal Human Subjects

1976 ◽  
Vol 128 (2) ◽  
pp. 184-187 ◽  
Author(s):  
Helen L. White ◽  
Malcolm N. McLeod ◽  
Jonathan R. T. Davidson
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Human Subjects ◽  
Normal Subjects ◽  
Enzyme Preparations ◽  
Human Red Blood Cells ◽  
Schizophrenic Patients ◽  
Normal Human ◽  
The Mean ◽  
Isoelectric Ph

SummaryCatechol O-methyltransferase of lysed human red blood cells was assayed under optimal conditions, using saturating concentrations of the substrates, S-adenosyl-L-methionine and 3,4-dihydroxybenzoic acid. The mean enzyme activity found in 24 normal subjects was 29.2 nmol/hr/ml RBC. The mean activity in blood of 33 female unipolar depressives was not significantly different from normal. However, higher enzyme activities were observed in the blood of 11 schizophrenic patients (38.9 nmol/hr/ml RBC). Partially purified enzyme preparations from blood of normal and schizophrenic individuals were indistinguishable with respect to substrate specificities, isoelectric pH values, and ratios of the two O-methylated products. Therefore it is unlikely that any defect in O-methylation which may occur in schizophrenia can be attributed to a change in the intrinsic properties of erythrocyte catechol O-methyltransferase.

BIOLOGICAL HALF-LIFE OF CAFFEINE IN PIGS

1970 ◽  
Vol 50 (1) ◽  
pp. 49-54 ◽  
Author(s):  
H. M. CUNNINGHAM
Keyword(s):  
Oral Dose ◽  
Water Content ◽  
Single Oral Dose ◽  
Plasma Levels ◽  
Half Life ◽  
Intramuscular Injection ◽  
Peak Plasma ◽  
Growing Pigs ◽  
Sufficient Time ◽  
Biological Half Life

Five experiments were conducted with growing pigs to determine the biological half-life of caffeine after injection or various periods of ingestion. Peak plasma caffeine levels were reached within 5 hr after a single oral dose and 2 hr after intramuscular injection, and then declined with a biological half-life of about 12 hr. The caffeine content of tissues was approximately proportional to their water content and 6% of orally administered caffeine was excreted in the urine. Upon continuous ingestion of caffeine, peak plasma levels were reached within 2 days, indicating that accumulation was quite limited. When 1.5 g of caffeine per kg of feed was fed from weaning to market weight, the withdrawal of caffeine 2 days prior to slaughter was sufficient time to insure that caffeine levels in the liver, muscle, kidney and backfat were below 1 μg/g.

Size variation of mastoid air cell system in Indian people at different age groups: a radiographic planimetric study

1990 ◽  
Vol 104 (8) ◽  
pp. 603-605 ◽  
Author(s):  
D. Chatterjee ◽  
T. B. Ghosh ◽  
B. B. Ghosh
Keyword(s):  
Human Subjects ◽  
Age Groups ◽  
Size Variation ◽  
Cell System ◽  
X Rays ◽  
Indian People ◽  
History Of ◽  
Normal Human ◽  
The Mean ◽  
Age And Sex

AbstractA radiographic planimetric study of mastoid air cell system was carried out on 100 normal human subjects of which 50 were males and 50 females–who were further subdivided into five age groups. They had no history of past ear disease or any other clinical ENT abnormality. The mean area of the mastoid air cell system was measured planimetrically on X-rays and the data analysed according to age and sex. It was 12.05±0.67 cm2 in males and 11.45±0.70 cm2 in females (which are more or less the same as that of Western people).The size of the cranial bones has no apparent role in the size variation of the mastoid air cell system. The development of the latter was very rapid up to 10 years of age in both sexes and it continued even after 20 years of age but at a much slower rate.

THE EFFECT OF INTRAVENOUSLY INJECTED CORTICOTROPHIN IN MAN

1963 ◽  
Vol 44 (2) ◽  
pp. 250-258 ◽  
Author(s):  
Pavo Hedner ◽  
Yngve Einerth
Keyword(s):  
Intravenous Injection ◽  
Half Life ◽  
Active Plasma ◽  
Maximal Effect ◽  
Acth Level ◽  
Plasma Acth ◽  
Single Intravenous Injection ◽  
Clinical Therapy ◽  
Adrenocortical Activity ◽  
Biological Half Life

ABSTRACT A single intravenous injection of 10 U. S. P. units of a purified ACTH preparation in man produced a maximal effect for at least 4 hours, and the effect was still significant 8 hours after the injection. The biological half life of this preparation was calculated and found to be about 1 hour. When given as an infusion over 8 hours this preparation was calculated to give a maximally active plasma ACTH level for 9½ hours. A significantly increased plasma corticosteroid level was present 12 hours after the beginning of the infusion, and a comparable response was obtained by the same amount of ACTH twice injected intravenously with 4 hours interval. A maximal adrenocortical activity was obtained with 50 U. S. P. units of the same ACTH injected intramuscularly and this persisted for at least 8 hours. The result of this investigation is not consistent with the view often held that the biological half life of exogenous ACTH is short and this discrepancy may be explained by the purified ACTH preparation used here. The relation between different methods of ACTH administration and their significance in clinical therapy is discussed.

Physiology of 24,25-dihydroxyvitamin D3 in normal human subjects

1982 ◽  
Vol 243 (5) ◽  
pp. E370-E374 ◽  
Author(s):  
R. Kumar ◽  
R. Wiesner ◽  
M. Scott ◽  
V. L. Go
Keyword(s):  
Production Rate ◽  
Biliary Excretion ◽  
Clearance Rate ◽  
Half Life ◽  
Human Subjects ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Dihydroxyvitamin D3 ◽  
Normal Human ◽  
24,25 Dihydroxyvitamin D3

We determined the metabolic clearance and production rates of 24,25-dihydroxyvitamin D3 in four normal healthy adults. We also examined the excretion of radioactivity in stool, urine, and bile after the intravenous administration of 24,25-[3H]dihydroxyvitamin D3 to human subjects. 24,25-Dihydroxyvitamin D3 is rapidly cleared from the plasma with a half-life of approximately 390 +/- 25 min (mean +/- SE). The metabolic clearance rate of 24,25-dihydroxyvitamin D3 was 9.2 +/- 1.5 liters/day with a production rate of 26.4 +/- 7.2 micrograms/day (mean +/- SE). Within 1 day 13.0 +/- 4.2% (mean +/- SE) of the administered dose had appeared in the stool; by day 7, 48.8 +/- 2.7% of the dose had appeared in the feces. Within 24 hr, 6.4 +/- 0.8% of the administered dose appeared in the urine; 7.4 +/- 1.8% of the dose had appeared in the urine within 2 days. The biliary excretion of 24,25-dihydroxyvitamin D3 was studied in two subjects. By 8 h, 15.3 +/- 1.3% of the administered dose had appeared in the bile. The metabolites present in bile, feces, and urine were much more polar than 24,25-dihydroxyvitamin D3. These results demonstrate that 24,25-dihydroxyvitamin D3 is rapidly cleared from plasma and is excreted in the feces (probably via the bile) and urine of normal human subjects.

Stoffwechselverhalten des anorganischen Kobalts und des in der Vitamin B12- bzw. Vitamin B12-Coenzym-Struktur organisch gebundenen Kobalts im Säugetier-Organismus

1964 ◽  
Vol 19 (11) ◽  
pp. 1032-1042 ◽  
Author(s):  
H. C. Heinrich ◽  
E. E. Gabbe
Keyword(s):  
Vitamin B12 ◽  
Half Life ◽  
Human Liver ◽  
Intramuscular Injection ◽  
Turnover Rate ◽  
Cobalt Content ◽  
Whole Body ◽  
Vitamin B ◽  
Biological Half Life ◽  
Body Retention

Chromatographically pure, vitamin B12-free 60CoCl2 as well as 60Co-vitamin B12 (60Co-cyanocobalamin and 60Co-aquocobalamin) and 60Co-vitamin B12-coenzyme (60Co-5.6-dimethylbenzimidazol-C5′-deoxyadenosyl-cobamid) were given orally and by injection in smallest amounts (10 — 100 pMol = 0.59-5.9 ng Co2®, 100 pMol = 136 ng vitamin B12 and 100 pMol = 158 ng vitamin B12-coenzyme) to female Sprague-Dawley rats.The whole body retention and excretion of the 60Co label was measured in a large volume radioactivity detector with liquid organic scintillators and 4 π-geometry. The biological half life and whole body metabolic turnover rate were calculated for the inorganic and organic cobalt from the kinetics of the 60Co whole body retention.After oral application of 100 pMol 60Co2® nearly all the 60Co is excreted already after 2 days within the faeces (90%), and the urine (15%). Only about 0.9% of the 60Co2⊕ leaves the rats with a biological half life of 18 days. After intramuscular injection of 100 pMol 60Co2⊕ about 91% of the 60Co are excreted in the urine and 10% in the faeces within four weeks. Only 4.6% of the 60Co2⊕ were eliminated with a biological half life of 28 days. The intramuscular injection of only 10 pMol 60Co2⊕ resulted in a faecal excretion of 82%, and an urinary excretion of 21% of the 60Co. A biological half life of 23 days was calculated for 8.6% of the 60Co2⊕. Inorganic cobalt is therefore practically not retained in the body and rapidly excreted mainly with the urine after injection and mainly within the faeces after oral uptake.In contrast to the inorganic cobalt a completely different metabolic behaviour is typical for the cobalt, which is incorporated in the organic structure of the vitamin B12- and vitamin B12-coenzyme molecules. This organic cobalt accumulates in the storage organs and tissues (kidney, liver etc.) after absorption as well as after injection of 100 pMol 60Co-vitamin B12 and 60Co-vitamin B12coenzyme. Only 15% of the 60Co-cyanocobalamin and 9—10% of the 60Co-aquocobalamin and 60°Covitamin B12-coenzyme are excreted within 48 hours after injection. The organ and tissue incorporated 60Co-vitamin B12 and 60Co-vitamin B12-coenzyme is metabolized with a biological half life of about 52 days. From the whole body pool size of 20 μg vitamin B12 and the biological half life a metabolic turnover rate of 0.27 μg vitamin B12/day or 1.34% of the vitamin-B12-pool per days was calculated for the whole body of the rat.The lacking organ and tissue retention of absorbed and injected 60Co2⊕ and its short biological half life in rats (if compared with the organic cobalt in the vitamin B12-structure) as well as the comparison of the total cobalt content of human liver (measured by physical techniques) with the cobalt content calculated from the vitamin B12-content of human liver (measured by microbiological assay) do not support a biological significance and function of inorganic cobalt in mammals. There is no evidence at the moment that any cobalt besides the cobalt in the vitamin B12 and vitamin B12-coenzymes is existing and biochemically active in humans or animals.

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