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Biomedical subjects

O Vesterqvist

Publications and source records attributed to O Vesterqvist.

61 records · Page 4Linked to original sources

Urinary excretion of 2,3-dinor-thromboxane B2 in man under normal conditions, following drugs and during some pathological conditions.

Quantitation of 2,3-dinor-thromboxane B2 (2,3-dinor-TxB2) was performed by gas chromatography-mass spectrometry. Under normal conditions the urinary excretion of 2,3-dinor-TxB2 was relatively constant in the same individual from day to day but during a 24-hour period a somewhat higher excretion rate was found during the first few hours after awakening. A pronounced reduction of the urinary excretion of 2,3-dinor-TxB2 was found after oral administration of 500 mg of aspirin or 50 mg of indomethacin, while 500 mg of paracetamol did not affect the urinary excretion. Increased excretion of 2,3-dinor-TxB2 was found in normal pregnancies and in diseases such as diabetes mellitus and homocysteinuria in comparison to the urinary excretion in normal healthy subjects. We also report one case, where the urinary excretion of 2,3-dinor-TxB2 was increased for a short period following the first symptoms of a myocardial infarction and those data indicate that thromboxane A2 (TxA2) may be of pathophysiological importance in human myocardial infarction. The results strongly indicate that measurements of the urinary excretion of 2,3-dinor-TxB2 should be meaningful as a tool for investigation of the involvement of thromboxane in various pathophysiological processes in vivo in man.

Acetaminophen↗

Development of a GC-MS method for quantitation of 2,3-dinor-6-keto-PGF1 alpha and determination of the urinary excretion rates in healthy humans under normal conditions and following drugs.

Tetradeuterated 2,3-dinor-6-keto-PGF1 alpha was used as internal standard in the development of a method for quantitation of 2,3-dinor-6-keto-PGF1 alpha in human urine based on gas chromatography - mass spectrometry. The urinary excretion rates of 2,3-dinor-6-keto-PGF1 alpha in twenty normal healthy males and females were 9.7 +/- 4.6 and 8.8 +/- 8.5 (mean +/- SD) ng/h respectively. A considerable inter- and intra-individual variation was found under normal conditions. It was also found that the urinary excretion of 2,3-dinor-6-keto-PGF1 alpha was increased about fivefold during and shortly after 30 min of strenuous jogging. Any data about the effect of nonsteroidal antiinflammatory drugs on the excretion rate of 2,3-dinor-6-keto-PGF1 alpha are difficult to interpret when considering the above findings. However, oral administration of 500 mg of aspirin did not seem to reduce the excretion rate of 2,3-dinor-6-keto-PGF1 alpha.

6-Ketoprostaglandin F1 alpha↗

Water diuretic effect of intravenously administered 9-deoxo-16, 16-dimethyl-9-methylene-PGE2 in conscious man.

The stable prostaglandin analogue 9-deoxo-16, 16-dimethyl-9-methylene-PGE2 (9-methylene-PGE2) was infused intravenously (0.5 ml/min) in the dosage of 20 micrograms/min for 2 h in conscious euhydrated man. The administration of 9-methylene-PGE2 rapidly induced an increase in urine flow (from 1.2 +/- 0.07 to 5.35 +/- 1.07 ml/min) concomitantly with a decrease in urine osmolality (from 827 +/- 40 to 193 +/- 44 mOsm/kg). Parallel to this tubular reabsorption of sodium (Na+), calcium (Ca2+) and magnesium (Mg3+) increased and that of potassium (K+) decreased as shown by a reduction in the clearance for respective ion divided by the clearance of inulin. Apparently the water diuresis was mediated by an inhibition of arginine vasopressin's (AVP) antidiuretic effect. The mechanism behind the increase in renal tubular reabsorbtion of Na+ could possibly be a 9-methylene-PGE2 mediated modulation of the renal aldosterone effect. However the protocol followed did not provide any evidence for this, or any other explanation of the observed renal retention of Na+, Ca2+ and Mg2+. The results reported here indicate that 9-methylene-PGE2 may have a future use as a water diuretic agent in patients suffering from water retention and dilutional hyponatraemia such as seen in the syndrome of inappropriate antidiuretic hormone (AVP) release commonly known as SIADH or Schwartz-Bartter's Syndrome.

16,16-Dimethylprostaglandin E2↗

Menses induction and second-trimester pregnancy termination using a polymeric controlled release vaginal delivery system containing (15S)15-methyl PGF2 alpha methyl ester.

A polymeric controlled release vaginal delivery system was developed for 15(S)15-methyl PGF2 alpha methyl ester. This delivery system is a reservoir-type device consisting of laminated membranes that are mounted on an inert holder. The delivery systems were designed to have in vitro steady-state release rates of 50 or 100 micrograms/hr. Included in the study were seven early pregnant (amenorrhea up to 49 days) patients who were treated with 50 micrograms/hr devices and five early pregnant patients who were treated with 100 micrograms/hr devices. Three second-trimester cases received a 50 micrograms/hr device and five received a 100 micrograms/hr device. Five of the seven early first-trimester patients given 50 micrograms/hr devices aborted completely. The plasma levels of PG in those patients were 400-600 pg/ml for up to 6 hours. In the two cases that did not abort completely, the plasma levels of drug dropped sharply after both patients had started to bleed vaginally one hour after administration of the device. All five early pregnant patients treated with 100 micrograms/hr devices aborted completely. None of the three second-trimester cases aborted within 24 hours following administration of the 50 micrograms/hr devices. Three of the five second-trimester patients aborted within 24 hours following treatment with 100 micrograms/hr devices. The plasma levels of drug reached 1-1.5 ng/ml during the first 2-5 hours and then declined, especially after rupture of the membranes. The variation of plasma levels of drug following vaginal administration of the devices in different individuals was considerably less than following vaginal suppositories. Therefore, this device seems to be close to an ideal delivery system for vaginal administration of abortifacients.

Abortifacient Agents↗

Plasma levels of 9-deoxo-16,16-dimethyl-9-methylene-PGE2 in connection with its development as an abortifacient.

Gaschromatographic-mass spectrometric quantitation of 9-deoxo-16,16-dimethyl-9-methylene-PGE2 in plasma samples obtained during constant intravenous infusion of the drug revealed that a plasma level of about 20 ng/ml was associated with high enough uterine contractility for induction of second trimester abortions. This level was therefore aimed for during the development of formulations and dose schedules for interruption of pregnancy with this drug. For the first time it was possible to induce second trimester abortions through oral administration of a prostaglandin analog, although the plasma levels were low giving a moderate success rate (about 50%) within 25 hours. Rectal administration of 20 mg of the drug at 6 hours intervals resulted in high enough plasma levels for second trimester abortions. Highly efficient dose schedules for interruption of early first trimester ("menses induction") and second trimester pregnancies through vaginal administration were developed. The frequency of side effects in the early first trimester were so low that "home treatment" was possible. Formulations suitable for 3, 6 or 12 hours preoperative dilatation of the cervix were also developed.

16,16-Dimethylprostaglandin E2↗

Effects of age and gender on the pharmacodynamics of omapatrilat in healthy volunteers.

Omapatrilat is the most clinically advanced member of a new class of cardiovascular drugs, vasopeptidase inhibitors. Omapatrilat is a single molecule that simultaneously inhibits neutral endopeptidase and angiotensin-converting enzyme, thus preserving vasodilator peptides and inhibiting production of the vasoconstrictor angiotensin II. In healthy male volunteers, omapatrilat decreased blood pressure while being generally well tolerated, with no serious adverse events. This study was undertaken to determine the effect of age and gender on the pharmacodynamics of omapatrilat. Healthy male or female volunteers between the ages of 18 and 80 were given a single oral dose of omapatrilat 40 mg. Neither age nor gender affected the vasopeptidase inhibition by omapatrilat. There were no differences between subject groups in the effect of omapatrilat on supine systolic, diastolic, or mean arterial blood pressure. Based on this study of healthy subjects, it can be concluded that it is not necessary to adjust the initial dose of omapatrilat for the treatment of hypertension based solely on age or gender.

Adolescent↗