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Biomedical subjects

J Kann

Publications and source records attributed to J Kann.

At least 19 recordsLinked to original sources
PubMed1992

Ofloxacin in human serum, urine, and tear film after topical application.

We evaluated the systemic absorption of ofloxacin eyedrops in humans and their availability in the tear film. Serum, urine, and tear film concentrations of ofloxacin were measured in 30 healthy women topically treated with 0.3% ofloxacin, in both eyes, four times daily for 10 1/2 days. Serum was collected before the first daily dose on days 1 and 11 and at 18 time points before the second dose. Maximum serum ofloxacin concentrations (1.89 +/- 1.13 ng/ml) after 10 1/2 days of topical dosing were more than 1,000 times lower than those reported after standard oral doses of 300 mg ofloxacin. Urine was collected for the 24-h period after the first daily dose on days 1 and 10. Topical ofloxacin was excreted in the urine primarily in unmodified form and recovery rates were significantly higher on day 10 (76.1 +/- 41.5%) than on day 1 (56.6 +/- 31.6%) (p less than 0.05). Both serum and urine data give evidence to accumulations of ofloxacin over a 10 1/2-day period. The low serum concentration at steady state suggests an extremely low potential for producing systemic effects. No systemic side effects attributable to topical ofloxacin were observed. Mild ocular irritation was reported by two patients while under treatment. Tears were collected 4 h after the first treatment on day 11 and at 5, 10, 20, 30, and 40 min after the second treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1989

Food effects on the nighttime pharmacokinetics of Theo-Dur tablets.

A randomized crossover study demonstrated major food effects on the pharmacokinetics of Theo-Dur, two 200-mg theophylline anhydrous sustained-release tablets, as an evening dose. These effects included a higher maximum serum theophylline level and relatively prolonged delay in drug absorption, both significant. The findings, which showed marked individual variation, could be clinically important for patients receiving evening medication.

Adult↗
PubMed1988

Comparison of quality of life on nitrendipine and propranolol.

A multicenter, randomized, double-blind, comparative study was conducted in 274 patients with mild to moderate hypertension to assess the impact of nitrendipine and propranolol on quality of life. After placebo baseline, 136 patients were given nitrendipine (5-20 mg b.i.d.) and 138 were given propranolol (40-120 mg b.i.d.). Quality of life was evaluated at baseline, weeks 6-10, and weeks 14-18 of the maintenance period. At weeks 6-10, the nitrendipine group became significantly more vigorous (p less than 0.01) and less fatigued (p less than 0.05) than the propranolol group. Propranolol subjects noted decreased problems of trembling hands (p less than 0.01) and alcohol use (p less than 0.05) than the nitrendipine subjects. No other significant differences between groups in mood states, troublesome conditions (insomnia, headaches, and loss of appetite), or sexual satisfaction were noted at this visit, and patient willingness to continue study medication was marginally significantly higher (p less than 0.1) in the nitrendipine group than in the propranolol group. At weeks 14-18, the propranolol subjects perceived significantly decreased problems with the "felt worried, tense, and drank alcohol to cope" factor (p less than 0.05); however, there were no differences between groups at this visit for Profile of Mood States (POMS) scores, sex life variables, or medication preference. Based on within-group analysis, the propranolol group perceived a reduction in partner sexual satisfaction (p less than 0.05). Overall, nitrendipine seemed to be better tolerated than propranolol.

Adult↗
PubMed1988

Availability of iron from four prenatal multivitamin/multimineral products.

Iron absorption from four prenatal multivitamin/multimineral preparations was compared in 36 healthy pregnant women in their second or third trimester of pregnancy. The products studied were the currently marketed formulations of Stuartnatal 1 + 1, Stuart Prenatal, Materna, and Natalins Rx. Each fasted subject received each of the four preparations, according to a randomized sequence, at intervals of three to seven days between drug administrations. Stuartnatal 1 + 1 demonstrated the best iron absorption. Total iron absorbed from Stuartnatal 1 + 1 and Stuart Prenatal was well above the additional daily 3.5 mg recommended during pregnancy. Following administration of Materna the amount of iron was only slightly above that recommended, and following Natalins Rx it was well below. All formulations were generally well tolerated by the subjects.

Adolescent↗
PubMed1987

Long-term antihypertensive effects and safety of nitrendipine in patients with mild, moderate, and severe hypertension.

A study of 31 patients with mild or moderate hypertension and 17 patients with severe hypertension was conducted to evaluate the long-term safety and efficacy of nitrendipine, a new calcium channel blocker with a long duration of action. Nitrendipine (5-40 mg bid) was given as monotherapy or in combination with hydrochlorothiazide and/or propranolol. Seventeen patients (54%) with mild to moderate hypertension were controlled with nitrendipine alone, but all except one patient with severe hypertension required combination therapy. In patients with mild or moderate hypertension, nitrendipine reduced supine blood pressure from a baseline mean 154/100 mm Hg to 136/87 mm Hg after 1 year of treatment (P less than .05). In patients with severe hypertension, supine blood pressure was reduced from 186/124 mm Hg to 148/91 mm Hg by the end of the planned treatment period (P less than .05; mean duration, 10 weeks). During extended observation, antihypertensive effect was sustained for up to 2.5 years and 1.6 years in patients with mild or moderate and severe hypertension, respectively. Nitrendipine was well tolerated; and only one patient, a moderate hypertensive, discontinued treatment because of pedal edema. The results of this long-term study show that nitrendipine alone or in combination with a diuretic and/or a beta blocker is a safe and effective agent for the treatment of patients with all degrees of hypertension.

Blood Pressure↗
PubMed1987

Effects of antacids and food on absorption of famotidine.

The effect of a high potency antacid and food on the bioavailability of famotidine was studied in 17 healthy volunteers in an open randomized three-way cross-over trial. After an overnight fast, famotidine was administered to each subject as follows: 40 mg famotidine orally alone; 40 mg orally with antacid; and 40 mg orally with a standard breakfast. Coadministration of the antacid caused a small but significant reduction in the maximum plasma concentration (Cmax) of famotidine from 81.1 +/- 54.2 to 60.8 +/- 21.6 ng ml-1 (P less than 0.05) and a small decrease in the area under plasma concentration-time curve [AUC] from 443.3 +/- 249.2 to 355.0 +/- 125.1 ng ml-1 h (P greater than 0.05). However, there was only a minimal effect of food on these parameters; the Cmax and [AUC] were 81.6 +/- 29.6 ng ml-1 and 434.8 +/- 145.9 ng ml-1 h, respectively.

Antacids↗
PubMed1985

Three-year caries increments after fluoride rinses or topical applications with a fluoride varnish.

251 9-12-yr-old children completed a 3-yr, double-blind, clinical trial of two caries preventive fluoride programs. Caries increments and progression patterns were compared in two groups of children who rinsed every fortnight with a 0.2% NaF solution or received biannual topical applications with a fluoride varnish (Fluor-Protector). Clinically recorded mean DFS increments were 3.3 +/- 0.2 (SE) in the rinse group and 3.5 +/- 0.2 in the varnish group. In both groups nearly half of these increments were recorded in the occlusal surfaces of second molars. The mean incremental DFS recorded radiographically on approximal surfaces of posterior teeth were 1.1 +/- 0.2 and 1.5 +/- 0.2 in the rinse and varnish group, respectively. None of the inter-group differences were statistically significant (P greater than 0.05). Detailed analyses of the radiographic scores revealed a similar and extremely slow caries progression in the two study groups and they strengthened the conclusion of equal clinical efficacy of the two treatments. None of the fluoride programs had been able to change preestablished patterns of caries development among the children.

Child↗
PubMed1979

Carcinogenic N-nitrosodimethylamine as a contamination in drugs containing 4-dimethylamino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one (amidopyrine, aminophenazone).

A total of 68 commercially available drugs containing amidopyrine were investigated for contamination with the strong carcinogen N-nitrosodimethylamine (NDMA). All samples contained varying amounts of NDMA. About half of the drugs contained 1--10 micrograms/kg, 40% contained 11--50 micrograms/kg, 7% contained 51--10 micrograms/kg and one sample had 370 micrograms/kg. NDMA-contents in batches of pure amidopyrine that had been utilized for preparation of drugs were higher than those in the respective drugs: about one-third was in the range of 20--50 micrograms/kg, one-third had 51--100 micrograms/kg, and one-third was above 100 micrograms/kg. There was, however, no correlation between NDMA-contents of batches of the pure substance and NDMA-contents of the drugs prepared from these batched. NDMA concentrations in the samples were inhomogenously distributed. It could be demonstrated that amidopyrine in substance reacts extremely rapidly with nitrogen oxides from the air to form NDMA. Ascorbic acid, which prevents nitrosamine formation in aqueous-acidic solution, under these conditions had no protective effect.

Aminopyrine↗
PubMed1978

Volatile and non-volatile N-nitroso compounds in foods and other environmental media.

A further series of cured meat products (meat loaf, liver loaf, bologna) has been investigated for their nitrosamine contents before and after frying. Contents in general were in the low microgram/kg range. An extensive study of nitrosamine contents of various types of cheese has been terminated. Although 45% of all samples showed indications of nitrosamine content, only 12% had concentrations of greater than 1 microgram/kg (1-6 microgram/kg); NDMA was more often found in hard and in soft cheese, than in other types. Analytical grade dichloromethane and chloroform have been found to contain N-nitrosomorpholine in concentrations of 2-376 microgram/kg (27-40% of the samples). The origin of the contamination is not known at present. A survey of the nitrosamine content of animal diets showed that 80% of all samples had contents of greater than 1 microgram/kg. NDMA (up to 79 microgram/kg) and NPYR (up to 26 microgram/kg) were most often found. There are indications that fish meal is the main source of contamination. Drugs containing amidopyrine (AP) have invariably been found to contain NDMA. Concentrations varied within wide limits (less than 10 microgram/kg - 371 microgram/kg). No correlation has been found between samples of pure AP and NDMA contents of drugs in which pure AP had been incorporated. Also, strong variations in NDMA contents have been found within individual batches, probably caused by the high reactivity of AP towards nitrogen oxides. The determination of N-nitroso-3-hydroxypyrrolidine has been further improved and a further series of food analyses for contents of this nitrosamine has been carried out. About 30% of the samples were positive with contents below or near 10 microgram/kg. An analytical method for determination of N-nitrosamino acids has been worked out. The method consists of a series of extraction, liquid/liquid distribution and chromatography steps; N-nitrosoamino acids are finally determined, after trimethylsilylation, with a TEA detector. First results on the occurrence of these compounds in various cured meat products are reported.

Animal Feed↗
PubMed1977

Occurrence of volatile N-nitrosamines in animal diets.

46 samples of commercially available diets for experimental animals have been analysed for their content of volatile N-nitrosamines by use of a nitrosamine-specific detection method (TEA-detector). 80% of all analysed samples were positive for N-nitrosodimethylamine with a maximum content of 79 ppb (microgram/kg) found in one sample. 59% of the samples were positive for N-nitrosopyrrolidine with 26 ppb as highest content. In 3 samples trace quantities (less than 1 ppb) of N-nitrosodiethylamine were found, one sample contained N-nitrosopiperidine (4 ppb).

Animal Feed↗