Comparison between human pharmacokinetics and imaging properties of two conjugation methods for 99mTc-annexin A5.

Annexin A5 (AnxA5) is a protein with high affinity for phosphatidyl serine, a phospholipid exposed on the cell surface during apoptosis. This phenomenon has been used for determination of cell death after myocardial infarction. To evaluate the potential of (99m)Tc-AnxA5 for in vivo scintigraphy of apoptotic cells, the pharmacokinetics and imaging properties of two radiopharmaceuticals, (99m)Tc-(n-1-imino-4-mercaptobutyl)-AnxA5 (I-AnxA5) and (99m)Tc-(4,5-bis(thioacetamido)pentanoyl)-AnxA5 (B-AnxA5), were studied. I-AnxA5 was administered intravenously to seven patients and one healthy volunteer, and B-AnxA5 was administered to 12 patients. All patients in the pharmacokinetic study had myocardial disease. Additionally, imaging was performed in a patient with acute myocardial infarction, as well as in three patients with different malignancies. The plasma concentration, excretion and biodistribution of (99m)Tc-AnxA5 were measured, as well as levels of AnxA5 antigen. The kinetic data of both radiopharmaceuticals in plasma fitted a two-compartment model. Both preparations had similar half-lives, but a different distribution over the two compartments. Plasma levels of AnxA5 antigen showed a broad variation. Both radiopharmaceuticals accumulated in the kidney, liver and gut. B-AnxA5 was excreted significantly faster than I-AnxA5. Both compounds can be used for imaging of the head/neck region, the thorax and the extremities. B-AnxA5 has a faster clearance and a lower radiation dose. Imaging of apoptosis in the abdomen will be difficult with both radiopharmaceuticals, and especially with B-AnxA5 because of its faster appearance in the gut.

Prevention of ventilator-associated pneumonia by oral decontamination: a prospective, randomized, double-blind, placebo-controlled study.

UNLABELLED: Colonization of the intestinal tract has been assumed to be important in the pathogenesis of ventilator-associated pneumonia (VAP), but relative impacts of oropharyngeal, gastric, or intestinal colonization have not been elucidated. Our aim was to prevent VAP by modulation of oropharyngeal colonization, without influencing gastric and intestinal colonization and without systemic prophylaxis. In a prospective, randomized, placebo-controlled, double-blind study, 87 patients received topical antimicrobial prophylaxis (gentamicin/ colistin/vancomycin 2% in Orabase, every 6 h) in the oropharynx and 139 patients, divided over two control groups, received placebo (78 patients were studied in the presence of patients receiving topical prophylaxis [control group A] and 61 patients were studied in an intensive care unit where no topical prophylaxis was used [control group B]). Baseline characteristics were comparable in all three groups. Topical prophylaxis eradicated colonization present on admission in oropharynx (75% in study group versus 0% in control group A [p < 0.00001] and 9% in control group B patients [p < 0.00001]) and in trachea (52% versus 22% in A [p = 0.03] and 7% in B [p = 0.004]). Moreover, topical prophylaxis prevented acquired oropharyngeal colonization (10% versus 59% in A [p < 0.00001] and 63% in B [p < 0.00001]). Colonization rates in stomach and intestine were not affected. Incidences of VAP were 10% in study patients, 31% in Group A, and 23% in Group B patients (p = 0.001 and p = 0.04, respectively). This was not associated with shorter durations of ventilation or ICU stay or better survival. Oropharyngeal colonization is of paramount importance in the pathogenesis of VAP, and a targeted approach to prevent colonization at this site is a very effective method of infection prevention. KEYWORDS: cross infection, prevention and control; respiration, artificial, adverse effects; antibiotics, administration and dosage infection control methods; pneumonia, etiology, prevention and control; intubation, intratracheal, adverse effects

The relative bioavailability of metoprolol following oral and rectal administration to volunteers and patients.

The pharmacokinetics, efficacy and safety of metoprolol tartrate 25 mg fatty suppositories were studied in 5 healthy volunteers and in 8 patients suffering from instable angina pectoris. Metoprolol 25 mg capsules were used as a control oral dosage form. Metoprolol showed a considerable rectal bioavailability (AUC, C max) and was absorbed quickly from the rectum (T max). In both groups rectal bioavailability was comparable. However, oral bioavailability was much lower in the volunteer group than in the patient group. Furthermore, ratios of metoprolol/alpha-OH-metoprolol concentrations in plasma and urine gave an indication for a partial avoidance of the first pass effect after rectal administration. Further research is necessary to define an exact rectal dosage of metoprolol. In all patients, a substantial drop in heart rate, systolic and diastolic blood pressure was seen after administration of the first suppository. Metoprolol suppositories appear to be an effective, safe and suitable alternative for patients who are in need for beta blocking medication and who are unable to take oral medication for a certain amount of time.

No effect of short-term omeprazole intake on acenocoumarol pharmacokinetics and pharmacodynamics.

AIMS: To investigate the effect of omeprazole on the pharmacokinetics of R- and S-acenocoumarol and on their combined anticoagulant activity. METHODS: Eight healthy male subjects completed a double-blind, randomized, placebo-controlled, two-way cross-over study. Subjects were given either omeprazole 40 mg or placebo once daily for 3 days. On day 2 of each study period, a single 10 mg oral dose of racemic acenocoumarol was administered and venous blood samples were collected for pharmacokinetic and pharmacodynamic assessments. A wash-out period of 2 weeks separated the two study periods. RESULTS: The pharmacokinetics of R- and S-acenocoumarol (AUC 3016 +/- 221 and 233 +/- 14 ng ml(-1) h, respectively) did not change after omeprazole (AUC 2929 +/- 256 and 220 +/- 18 ng ml(-1) h, respectively). Anticoagulant activity (INRmax 1.7 +/- 0.1) was unaffected by co-administration of omeprazole (INRmax 1.7 +/- 0.1). CONCLUSIONS: The short-term intake of omeprazole does not affect acenocoumarol pharmacokinetics or pharmacodynamics. These data differ from the results of previous studies on the effect of omeprazole on warfarin, suggesting a different in vivo interaction profile of omeprazole on acenocoumarol than on warfarin. Drug interaction studies with oral anticoagulants should not be restricted to the use of warfarin.

The role of intragastric acidity and stress ulcus prophylaxis on colonization and infection in mechanically ventilated ICU patients. A stratified, randomized, double-blind study of sucralfate versus antacids.

UNLABELLED: This study evaluates the effects of sucralfate and antacids on intragastric acidity, colonization of stomach, oropharynx and trachea, and the incidence of ventilator-associated pneumonia (VAP) in mechanically ventilated patients in intensive care units. We conducted a prospective randomized double-blind trial in which patients were stratified on initial gastric pH. Intragastric acidity was measured with computerized, continuous intragastric monitoring. The diagnosis of VAP was established with protected specimen brush and/or bronchoalveolar lavage. The study included consecutive eligible patients with mechanical ventilation and nasogastric tube. INTERVENTIONS: After stratification on initial intragastric pH into two groups, patients from both groups were randomly assigned to receive either antacids (a suspension of aluminum hydroxide and magnesium hydroxide), 30 mL every 4 h, or sucralfate, 1 g every 4 h. Continuous intragastric pH monitoring was performed in 112 patients (58 antacids, 54 sucralfate). Using predetermined criteria, colonization of stomach, oropharynx, and trachea, and the incidence of VAP were assessed. Altogether, 141 patients were included (74 receiving antacids, 67 sucralfate) and continuous intragastric pH monitoring was performed in 112 patients, with a mean of 75 h per patient. The median pH and the percentage of time with a pH < 4.0 were calculated from each measurement. No significant differences in median pH values (4.7 +/- 2.2 and 4.5 +/- 2.0 for antacids and sucralfate, respectively) were observed. Median pH values were higher in patients with gastric bacterial colonization than in noncolonized patients (5.5 +/- 2.1 and 3.3 +/- 2.0, p < 0.01), but colonization of oropharynx and trachea was not related to intragastric acidity. Thirty-one patients (22%) developed VAP, with a similar incidence in both treatment groups. In addition, antibiotic use, duration of hospitalization, and mortality rates were similar in both groups. Enteral feeding did not change intragastric acidity significantly but increased gastric colonization with Enterobacteriaceae, without influencing oropharyngeal and tracheal colonization. Antacids and sucralfate had a similar effect on intragastric acidity, colonization rates, and incidence of VAP. Intragastric acidity influenced gastric colonization but not colonization of the upper respiratory tract or the incidence of VAP. Therefore, it is unlikely that the gastropulmonary route is important for the development of VAP.

[Sex hormones]. / De geslachtshormonen.

PIP: An overview of the sex hormones is presented. Testosterone is a natural androgen produced in the testes, adrenal glands, and ovaries. It has anabolic as well as androgenic effects. Testosterone is used to treat inoperable breast cancer and osteoporosis, and to stimulate erythropoesis. Androgens are absolutely counterindicated in cases of prostate cancer. Estrone, estradiol, and estriol are natural estrogens produced in the ovaries, placenta, testes, and adrenal glands. These hormones also influence the production of gonadotropins by the pituitary gland. Estrogens are used to treat menopausal disorders, ovarial insufficiency, estrogen-independent breast cancer, prostate cancer, and in some cases pregnancy disorders. Estrogens and progestagens are 2 components used in oral contraceptives. Progesterone, a natural progestagen, is produced by the corpus luteum. It promotes the proliferation phase of the endometrium, fertilization, and nidation, and it works to maintain pregnancy. Progesterone is used to treat spontaneous abortion, corpus luteum insufficiency, and endometrial cancer.^ieng