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Biomedical subjects

W Krause

Publications and source records attributed to W Krause.

At least 127 records · Page 7Linked to original sources
PubMed1995

Comparison of iopamidol and ioversol in vitro and in animal studies.

In the present series of studies we investigated differences in vitro and in animal experiments between iopamidol (Iopamiron, CAS 60166-93-0) and ioversol (CAS 87771-40-2). The studies included the in vitro investigations partition coefficient, lysozyme inhibition, coagulation time and erythrocyte morphology as well as the in vivo paradigms acute toxicity, neural toxicity, general behavior/locomotor activity and angiography. Iopamidol was superior to ioversol in most of the tests. In spite of its higher hydrophilicity, ioversol did not show improved tolerance in comparison to iopamidol.

Angiography↗
PubMed1995

[Evidence of Cryptosporidium in children with symptomatic enteritis from the Leipzig administrative area 1987-1992].

From 1987 to 1992 stool samples of 3235 diarrheic children at the age from 1 to 14 years in the Leipzig district were examined for Cryptosporidium spp. In 58 patients (= 1.8%) oocysts have been detected. Most of the positive children (= 81%) were less than 7 years old. A seasonal increasing of prevalence was observed in August and in the following months. According to anamnestic informations of treating physicians all patients were immunocompetent. The clinical symptomatology comprised diarrhoea, vomiting, fever and stomach ache. Animal contacts were known in 52% of the patients. Stool examinations for diagnosis of Cryptosporidium are recommended in unclear diarrhoeas, also in immunocompetent patients. The role of Cryptosporidium spp. as opportunists in immunodeficiency is especially commented.

Animals↗
PubMed1995

Circadian plasma level profile of lisuride in rats and mice after continuous administration via the diet.

Lisuride (Dopergin, CAS 18016-80-3), a dopamine D2 agonist, was administered to male and female rats and mice continuously via the diet for 14 days. The doses were 0.2 mg/kg/d in mice and 1 mg/kg/d in mice and rats. Plasma level profiles (0-22 or 24 h) were determined by measuring lisuride concentrations by radioimmunoassay. At all doses a plateau-like plasma level of lisuride was observed. A clear circadian rhythm of lisuride concentrations (highs during night, low levels during day) was found for male rats (1 mg/kg/d) and for male mice (0.2 mg/kg/d). Female animals did not show this phenomenon as pronounced. At the same dose of 1 mg/kg/d rats showed higher plasma levels than mice. For males the ratio of total AUCs was 1.9 and for female animals 8.6.

Animals↗
PubMed1995

The significance of computer-assisted semen analysis (CASA) for diagnosis in andrology and fertility prognosis.

The estimation of seminal parameters by CASA improves the objectivity, precision and reproducibility of values measured. Novel parameters, such as sperm velocity and characteristics of track direction, become measurable. An important advantage is direct on-line documentation. The biological significance of CASA parameters with respect to specific types of motility pattern or to fertility prognosis, however, is questionable. An important field is the analysis of pharmacological and toxicological influences on sperm motility. The evaluation of sperm morphology by CASA is not yet an established method.

Fertility↗
PubMed1994

Dose proportionality of iopromide pharmacokinetics and tolerability after i.v. injection in healthy volunteers.

Twelve healthy male volunteers participated in a single-blind, randomised, placebo-controlled cross-over study of i.v. iopromide in doses of 15 g iodine or 80 g iodine infused over a period of 15 min. The volunteers were observed for three days during which time blood samples, urine and faeces were collected. The terminal disposition phase half-life of iopromide was 2 h and 1.9 h, and the total clearance was 110 and 103 ml.min-1 at the lower and at the higher dose levels, respectively. The steady state volume of distribution was 16 and 17 l, indicating predominantly extracellular distribution of iopromide. Statistical analysis (one-sided t-test) showed that all the target parameters (AUC, half-life and urinary excretion) were equivalent at both dose levels, indicating dose proportionate, first order kinetics of iopromide over the large dose range tested. Iopromide was well tolerated after both doses.

Adult↗
PubMed1994

Autonomic regulation of nasal vessels during changes in body position.

The effects of postural changes on nasal airflow and nasal capillary blood flow were investigated in 15 healthy volunteers. Measurements were performed following nasal application of saline solution (control), the alpha-1 receptor antagonist prazosin, the alpha-2 receptor antagonist yohimbine, and after application of both prazosin and yohimbine. Nasal airflow in the control experiments did not significantly differ in the upright (362 +/- 166 ml/s), dorsally recumbent (350 +/- 167 ml/s) and 70 degrees head down position (311 +/- 167 ml/s). Following application of prazosin, nasal airflow was reduced to 223 +/- 121 ml/s in the upright position. Prazosin treatment significantly reduced nasal airflow to 177 +/- 111 ml/s when subjects were placed in dorsally recumbent positions and to 117 +/- 104 ml/s in 70 degrees head down positions (P < 0.001). Following application of yohimbine, nasal airflow remained stable when subjects were turned from upright (348 +/- 165 ml/s) to supine position (352 +/- 186 ml/s), whereas it was reduced to 199 +/- 137 ml/s in the head-down position. Application of both prazosin and yohimbine significantly increased nasal capillary blood flow in laser Doppler flowmetry measurements (P < 0.05). Changes in body position with or without application of the active drugs did not alter nasal capillary blood flow. These findings suggest that nasal congestion due to increased filling pressure in nasal capacitance vessels following postural changes is mainly prevented by alpha-1 adrenergic mechanisms.

Administration, Intranasal↗
PubMed1994

[The male climacteric. A responsibility for dermatologic andrology?].

Sexual impotence is considered to be the main symptom of the male climacteric, corresponding to the female menopause. While the female climacteric is routinely observed and treated by gynecologists, there are no adequate institutions for the treatment of the corresponding male complaints. Like ovarian secretion of estrogens, which declines and thus causes the female climacteric syndrome, the endocrine metabolism of the testes decreases with increasing age. The period of this decrease, however, is far more extended than that of estrogen secretion in women. Several recent studies have yielded evidence that any disease--irrespective of its kind--in the aging man influences the decrease of testosterone levels more markedly than his age. In 1986 a study group in New England inaugurated the "Massachusetts Male Aging Study" in which healthy men in different age groups were tested for hormone levels. The most prominent result of this study was a decrease in mean testosterone levels by 1% and a decrease in the mean free testosterone levels by 1.2% per year of age. The study also allows recommendations for hormone substitution. The decrease in sexual function in the aging male does not correlate with the decrease in testosterone production. In summary, however, there is no doubt that the frequency of sexual dysfunction increases with advancing age, partly because of drug interactions. As there does not seem to be any sound basis for assuming an endocrine basis for the male climacteric, other reasons must probably be sought for the male climacteric or mid-life crisis.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Physicochemical parameters of x-ray contrast media.

RATIONALE AND OBJECTIVES: Osmolality, including "dynamic osmolality," which is observed during dilution in the plasma, viscosity, density, and partition coefficient of 11 commercially available contrast media and two new nonionic monomers were determined. METHODS: Osmolality was measured by vapor pressure osmometry, viscosity by determining flow in microcapillaries, and partition coefficient in n-octanol or n-butanol/water mixtures by inductively coupled plasma mass spectroscopy or x-ray fluorescence analysis of iodine concentrations. RESULTS: For the commercially available contrast media, the following statistically significant ranking of osmolality was obtained at 300 mg iodine/mL: iotrolan << ioxaglate < iopromide < iopamidol < ioversol = iohexol < iopentol << meglumine diatrizoate. The novel nonionic monomers, ZK 119095 and ZK 139129, had very low osmolalities, and ZK 139129 was isotonic to blood. The partition coefficient for the system n-octanol/water was lowest for the ionic compounds ioxaglate and diatrizoate followed by the nonionic dimer iotrolan. In n-butanol, iotrolan showed the lowest partition coefficient. CONCLUSION: "Dynamic osmolalities" of contrast media may differ from static values possibly because of the formation of "quasi-oligomers." Especially for ZK 139129, disaggregation occurred during dilution and the osmolality increased slightly. However, osmolality was lower than for any other monomer during the whole dilution process.

Animals↗
PubMed1994

Elimination of the diatrizoate-induced effects on the microcirculation by the prostacyclin derivative, iloprost.

RATIONALE AND OBJECTIVES: Contrast media, especially high-osmolar ionic compounds elicit drastic effects on the microcirculation. In some areas of the microcirculatory network, blood flow decreases up to total stasis; in other areas, blood velocity increases. The authors studied the effect of the stable prostacyclin derivative, iloprost, added to the diatrizoate formulation on the number of perfused microvessels in the rat intestine. METHODS: Diatrizoate (600 mg iodine/kg) and increasing concentrations of iloprost, ranging from a total dose of 0 to 560 ng/kg, were injected intravenously into groups of four anesthetized male rats. The number of unperfused microvessels in the intestine were determined by in vivo microscopy. Each animal received two treatments at an interval of 35 minutes. One treatment consisted of diatrizoate alone, the other treatment consisted of diatrizoate plus iloprost. Two animals of each group received first diatrizoate alone and then diatrizoate plus iloprost. The other two animals first received diatrizoate plus iloprost and then diatrizoate alone. RESULTS: Diatrizoate alone reduced the number of perfused microvessels by 45%. The addition of iloprost resulted in a dose-dependent improvement of microcirculation. At a dose of 280 ng/kg, the effects of diatrizoate were completely abolished. Increasing the dose further diminished this effect. CONCLUSIONS: The addition of iloprost to diatrizoate eliminates the deleterious effects of diatrizoate on microcirculation.

Animals↗
PubMed1994

Cardiac and hemodynamic tolerability of iopromide with or without sodium or iloprost and of ioversol in the anesthetized rat.

RATIONALE AND OBJECTIVES: In this study, the cardiac and hemodynamic effects of iopromide alone were compared with those of two combination preparations (iopromide plus sodium and iopromide plus the prostacyclin analog iloprost) and with ioversol after left ventricular bolus administration in rats. METHODS: The tracheae of anesthetized male Wistar rats were cannulated to facilitate spontaneous respiration. The animals were set up to allow recording or calculation of the following parameters: femoral arterial blood pressure (systolic, mean, and diastolic), left ventricular end-diastolic pressure, heart rate, and contractility. Iopromide (330 mg iodine/mL; 2 g iodine/kg) with or without sodium chloride (20 mmol/L) or iloprost (approximately 50 ng/mL; dose: 300 ng/kg) was injected into the left ventricle within 30 seconds. Ioversol (320 mg iodine/mL) was used at the same dose and injection rate. RESULTS: Iopromide and ioversol induced transient changes in blood pressure (decrease followed by an increase), left ventricular end-diastolic pressure (increase), heart rate (decrease), contractility (increase followed by decrease), and electrocardiogram (extrasystoles, ST depression). Ioversol exhibited more pronounced effects on contractility and ST depression. The differences were statistically significant. The addition of sodium to iopromide resulted in a slight, but not significant influence on cardiac or hemodynamic parameters. The addition of iloprost improved ST depression slightly and hemodynamics significantly resulting in less mean and end-diastolic blood pressure change and less heart rate decrease. Contractility was significantly increased compared with iopromide with or without sodium. CONCLUSIONS: The addition of sodium or iloprost to nonionic contrast media might be useful in the alleviation of cardiac and hemodynamic side-effects.

Anesthesia, General↗
PubMed1994

Utilization of cryopreserved semen in tumor patients.

Treatment with cytotoxic drugs or with radiation in order to manage a tumor or another life-threatening disease involves a potential hazard to male fertility. In these cases cryopreservation of semen is recommended. However, the number of patients requesting the subsequent insemination of their partner is rather low. It would be of interest if patients with a high probability for desiring use of the cryodeposit for insemination could be identified. During the years 1985-1992 we performed cryopreservation in 29 patients attending our department. One year following cryopreservation the utilization of the cryodeposit was analyzed: 29 patients were not interested in further maintenance, 2 patients died, 3 patients requested use for insemination, 31 patients decided to maintain the semen further in a commercial cryobank, 17 patients had a complete restitution of spermatogenesis within the observation period. In 7 patients the interval is yet below 1 year. The different modes of utilizing the cryodeposit were analyzed in relation to the semen quality, age, status, kind of disease and primary treatment. None of these factors possibly influencing the utilization showed differences between the groups. We conclude that it is impossible to predict the probability of the use of a cryodeposit of semen based on the examined patient characteristics at the time of preservation. We plan to further on offer semen preservation to all patients requiring it in a situation of threatened fertility, bearing in mind that the relative costs of the cryopreservation are low.

Adult↗
PubMed1994

Preclinical testing of iopromide. 1st communication: pharmacological evaluation.

Pharmacological and pharmacokinetic characteristics of the non-ionic monomeric X-ray contrast agent iopromide (Ultravist, CAS 73334-07-3) were evaluated in preclinical studies. The scope of investigations included in vitro tests such as the determination of protein binding, the inhibition of complement, lysozyme, urokinase, platelet aggregation, the release of histamine, the influence on thromboplastin time. In vivo studies included bleeding time in rat, neural tolerance after intracisternal injection or administration into the carotid artery. Pharmacokinetic studies were performed in rats and dogs. Iopromide could be shown to be well tolerated in all the tests and species. Its pharmacokinetics was in agreement with the characteristics of an extracellular contrast agent with rapid renal elimination.

Animals↗
PubMed1994

Preclinical testing of iopromide. 2nd communication: toxicological evaluation.

Toxicological characteristics of the non-ionic monomeric X-ray contrast agent iopromide (Ultravist, CAS 73334-07-3) were evaluated in rats, rabbits, guinea-pigs and dogs. The scope of investigations included acute toxicity studies, systemic tolerance investigations with repeated applications, reproduction toxicity studies, examinations on the genotoxic and contact-sensitizing potential and local tolerance studies. Iopromide could be shown to be well tolerated in all the tests and species.

Animals↗
PubMed1994

[Optimizing intravenous bolus contrast medium injection in cervical CT diagnosis].

PURPOSE: A prospective, comparative study of 60 patients for optimizing contrast medium (CM) administration for spiral CT of the neck. METHODS: Prior to the investigation, the patients were randomly assigned to three groups (n = 20 each): a) conventional CT technique, interscan duration 10 s, CM volume 150 ml of Ultravist 300 (30 ml at a flow rate of 1.5 ml/s, the remaining 120 ml as maintenance dosage of 0.5 ml/s); b) so-called dynamic CT technique, interscan duration 5 s, CM volume 100 ml (200 ml at a flow rate of 2 ml/s and 80 ml with a flow rate of 0.5 ml/s); c) spiral CT technique, total investigation time to store the crude data was 30 s, a CM dosage of 50 ml at a flow rate of 2 ml/s (30 ml) in the first phase and 0.7 ml/s (20 ml) in the second phase was studied. RESULTS: The current evaluation of the CM time-density course, image quality, diagnostic efficiency, and investigation time showed that a good to very good contrast medium enhancement of the neck vessels was achieved in all groups so that pathological findings were well differentiated. CONCLUSIONS: The CM volume could be reduced to a third of the original used amount without loss of diagnostic security by use of the spiral CT technique.

Adolescent↗
PubMed1994

[Amalgams--discussion of a controversy].

Amalgam fillings are still widely used in dentistry. Based on toxicological data, patient's and medical staff's risk of mercury poisoning is evaluated; pharmaco-prophylaxis against chronic poisoning is discussed.

Dental Amalgam↗