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Biomedical subjects

N Neumann

Publications and source records attributed to N Neumann.

12 recordsLinked to original sources
PubMed1992

Active control equivalence trials: some methodological aspects.

The therapeutic efficacy of an investigational new drug is best demonstrated in clinical trials against a placebo control. However, ethical requirements increasingly preclude the use of an inactive control substance as a treatment alternative, as clinical testing to compare the effects of active treatments, has become more frequent. The statistical evaluation and interpretation of these trials is complex and requires the demonstration of 'equivalence' or 'at-least equivalence' between the experimental drug and a comparable standard therapy. The design of controlled clinical trials to compare the effects of moclobemide, a new and selective monoamine oxidase-A inhibitor, with those of standard tricyclic antidepressant drugs involved the refinement of selection strategies, formulation of hypotheses, means of statistical analysis and clinical interpretation.

Antidepressive Agents↗
PubMed1992

Differential effects of two dihydropyridine calcium antagonists in humans.

We studied the effects after single doses of niguldipine (0.3, 0.6, and 0.9 mg intravenously; 8 and 16 mg orally) and nifedipine (2 mg intravenously; 20 mg orally) in healthy male volunteers in randomized placebo-controlled experiments. Total peripheral resistance (TPR), heart rate-corrected electromechanical systole (QS2c), and preejection period (PEPc) were assessed noninvasively. Both drugs induced a similar pronounced decreased in TRP, indicating peripheral vasodilation, followed by increasing heart rate and cardiac output, a decrease in diastolic blood pressure, and a shortening of the PEPc. QS2c was unchanged after niguldipine. The prolongation of QS2c after oral nifedipine is suggestive of a negative inotropic effect. We conclude that the vasodilatory effects of dihydropyridines may (as for nifedipine) or may not (as for niguldipine) be associated with changes that are suggestive of negative inotropic effects, and that this difference is detectable by noninvasive methods in healthy subjects.

Administration, Oral↗
PubMed1992

[The effect of UV-A and UV-B irradiation on the skin barrier. Skin physiologic, electron microscopy and lipid biochemistry studies].

In order to gain insight into the effects of UV-irradiation on the skin barrier, functional (skin reactivity), electron microscopic and lipid-biochemical studies were performed. In three different irritation models, both UV-A-irradiated and UV-B-irradiated areas proved to be more resistant to damage than normal skin, providing evidence for improvement of barrier function after UV irradiation. Electron microscopic evaluation showed that UV-B induced a significant increase in horny cell layers, whereas after UV-A no change was detected. However, both UV-B and UV-A exposure resulted in an increase in the amount of all stratum corneum lipids. This was also observed in all major ceramide subfractions, which are believed to be the essential lipid constituents for the epidermal barrier function. These findings may explain the known beneficial effects of phototherapy in dermatoses with impaired barrier function, i.e., atopic dermatitis.

Dose-Response Relationship, Radiation↗
PubMed1991

Photopatch testing: the 5-year experience of the German, Austrian, and Swiss Photopatch Test Group.

A cooperative photopatch test study was conducted by 45 dermatologic centers in Austria, Germany, and Switzerland. Results obtained from 1985 to 1990 are presented. A standard photopatch test tray of 32 substances was applied to the back of patients with suspected photosensivity. After applications for 24 hours, test sites were irradiated with 10 joules/cm2UVA. Unirradiated controls were included. Readings were performed immediately and 24, 48, and 72 hours after irradiation; responses were qualitatively graded on a 4-point scale. All data were stored and processed by a computer. With computer-assisted analysis of reaction patterns photoallergic reactions were identified and distinguished from phototoxic reactions. Data of 1129 patients were evaluated. Among a total of 2859 positive test reactions in 870 patients, 2041 in 778 patients were found to be photoinduced and 818 in 413 patients were contact reactions; 108 reactions in 83 patients were classified as photoallergic. Nonsteroidal anti-inflammatory drugs, disinfectants, sunscreens, phenothiazines, and fragrances caused most often photoallergic reactions. Many unspecific phototoxic reactions were induced by tiaprofenic acid, promethazine, carprofen, chlorpromazine, fenticolar, wood balsam of Peru, and perfumes. Despite the distinction between photoallergic and phototoxic responses, many test reactions lacked relevance for the patients' dermatoses.

Adolescent↗
PubMed1991

[Chronic actinic dermatitis. Concept and case examples].

Two women patients with chronic eczematous dermatitis, who also developed extremely severe, persistent photosensitivity during a course of 10 and over 40 years, are presented. Both patients had an atopic history with positive immediate skin reactions. Patch and photopatch tests revealed sensitization to several contact allergens, and in one case also a photocontact allergy. The action spectrum of the photosensitivity was confined to UV-B; it was possible to provoke eczematous skin reactions with doses smaller than 1 mJ/cm2 UV-B. Both patients were successfully treated with PUVA therapy. These case reports demonstrate the difficulty of nosological classification of chronic eczematous photosensitive dermatoses under the traditional terms persistent light reaction, photosensitive eczema, photosensitivity dermatitis, and actinic reticuloid. Chronic actinic dermatitis is defined clinically by chronic dermatitis on skin exposed to sun, histologically by spongiotic dermatitis, and photobiologically by experimental provocation of spongiotic dermatitis with UV-B and often also longer wavelengths in the absence of a photoallergen. Chronic actinic dermatitis should be used as a general term in addition to the more specific terms listed above.

Biopsy↗
PubMed1990

Early versus late surfactant replacement therapy in severe respiratory distress syndrome.

26 preterm infants with severe respiratory distress syndrome (RDS) have been treated at different ages with a single dose of natural porcine surfactant (Curosurf, 200 mg/kg). Criteria for treatment included clinical and radiological signs of severe RDS (grade III-IV), requirement of artificial ventilation and an FiO2 greater than or equal to 0.6. Nineteen neonates have been subjected to early treatment (2-15 h of age, mean birth weight SD: 1201 +/- 387 g) and 7 patients to late treatment (greater than 15 h to 48 h of age, birth weight SD 1624 +/- 649 g). Average FiO2 before treatment was 0.88 in early-treated patients and 0.8 in late-treated patients, age at treatment was 4.6 h and 36 h, respectively (median). Both early- and late-treated infants exhibited an improvement in oxygenation (more than twofold increase of the PaO2/FiO2 ratio) within 5 minutes after initiation of therapy. Average duration of intermittent pressure ventilation was 15 days in the early treatment group and 19 days in the late treatment group. Total exposition to greater than 21% oxygen was 21 days in early-treated and 48 days in late-treated infants. Pneumothorax occurred in none of the patients. All early treated infants survived without signs of severe bronchopulmonary dysplasia (BPD greater than 21% O2, greater than 90 days plus radiological changes). However, two out of seven late-treated infants developed severe BPD; one patient died as a consequence of cardiopulmonary deterioration. Two patients in the early treatment group died of nonpulmonary complications. We conclude that surfactant replacement therapy should probably be initiated as soon as possible after manifestation of severe RDS.

Birth Weight↗
PubMed1990

[Surfactant substitution in severe respiratory distress syndrome in premature infants weighing less than 1,000 g].

19 preterm infants with severe respiratory distress syndrome (RDS) were treated with a single dose of natural porcine surfactant (Curosurf, 200 mg/kg). 9 patients had a birth weight of less than 1000 g (845 +/- 112 g, mean +/- SD and the mean gestational age was 27.2 +/- 2.1 weeks). The other 10 had a birth weight of greater than 1000 g (1521 +/- 218 g and a mean gestational age 31 +/- 2.8 weeks). Age at treatment was 3 h in infants less than 1000 g and 4 h in patients greater than 1000 g. Both groups of infants showed a rapid improvement in oxygenation and gas exchange within minutes after surfactant replacement. Exposition to greater than 60% and greater than 40% oxygen was identical in both groups. However, time in greater than 21% oxygen was significantly longer in infants less than 1000 g (median 30 days, 8.5 days in patients greater than 1000 g, p less than 0.01). The duration of mechanical ventilation was 33 days, in patients greater than 1000 g and 5 days; p less than 0.01. None of the infants developed a pneumothorax, but 6 out of 9 patients less than 1000 g developed mild bronchopulmonary dysplasia. 2 infants less than 1000 g died at day 5 and day 11 from cardio-circulatory arrest following ligation of a patent ductus arteriosus, and nosocomial septicaemia, respectively. Prolonged mechanical ventilation and exposure to oxygen in patients less than 1000 g cannot be attributed to surfactant deficiency alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Birth Weight↗
PubMed1985

Improved quality and information in thyroid scintigraphy.

We compared rectilinear scanning, analogous gamma-camera imaging and imaging using a gamma camera interfaced to a computer in order to determine which of these techniques is superior for thyroid scintigraphy. Forty patients with and without goitre and irregular activity distribution were imaged using each of the three techniques. The sets of three scintigrams per patient were rated by seven physicians. These ratings were statistically analysed using a new distribution-free test. Thyroid scintigraphy using a gamma camera interfaced to a computer turned out to be the best method, especially for detecting circumscribed areas of increased uptake. We conclude that this was due to a combination of the following factors: a computer matrix of 128 X 128 pixels in combination with an acquisition zoom of 1.5, the high count density of the scintigrams, computer-controlled documentation after data acquisition and the use of a continuous grey scale for documentation. The improved quality and information content of the scintigrams obtained using a gamma-camera/computer system could improve the diagnostic value of thyroid scintigraphy, especially when the scintigrams are also evaluated quantitatively.

Humans↗
PubMed1979

Hormonal influences on the dog prostate--a correlation study with light microscopy, transmission and scanning electron microscopy.

Dog prostates under defined hormonal influences were investigated by light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The normal acinar cell apices exhibited well-developed, densely packed microvilli. TEM demonstrated numerous secretory granules, indicating a high secretory activity. Following castration, the acinar cells of the dog prostate showed rounded apices. Most of the microvilli disappeared and only knob-like protrusions were seen. Castrated dogs following administration of 3 alpha-androstandiol showed fewer microvilli than the controls; however, a well-developed undulating surface could be observed. Castrated dogs given 3 alpha-androstandiol and cyproterone acetate showed almost completely atrophic glandular cells. Prostates of dogs with spontaneous benign prostatic hyperplasia (BPH) were characterized by pleomorphism of cell shapes and surfaces. The different hormonal influences induced changes of the prostatic surface structures and secretory activity.

Androstanols↗