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Biomedical subjects

H Langer

Publications and source records attributed to H Langer.

At least 19 recordsLinked to original sources
PubMed1992

[The prevention of mucosal lesions during oropharyngeal irradiation with a dental-filling shield].

In patients with metallic dental fillings radiation therapy to the oral cavity can cause mucous membrane lesions, which are more severe than expected. They appear as circumscribed erosions, opposite to metallic fillings and are caused by an increase in radiation dose through secondary radiation due to the higher density and atomic number of the filling material. This dose increase can be directly measured with 0.1 mm thin sheets of graphite-loaded TLD's (LiF, Vinten). For Co-60 gamma rays a commercial amalgam filling caused a dose increase by a factor of 1.7. The half value layer for this additional radiation was measured to be approximately 0.4 mm tissue. In order to avoid painful mucous membrane ulcerations which are even more a problem if hyperfractionated treatment schedules are used, we constructed individual dental shields for each patient. As shielding material we used a dental impression material (Optosil P+1 Bayer). This method was tested in 35 patients, in all of them circumscribed mucous membrane ulcerations could be avoided. The method proved to be fast and simple and was very well tolerated by all patients.

Dental Amalgam↗
PubMed1990

Aerobic glycolysis in the retina of the crab Ocypode ryderi.

Our experiments on the isolated and superfused crab retina reveal that pronounced gradients for PO2 and pH exist in this tissue. The PgO2 profiles and a delayed recovery of the PgO2 after hypoxia seem to be a consequence of the oxygen consumption inside the tissue, as much as both characteristics can be abolished by impairment of electron transport in the respiratory chain after application of antimycin A. The pH profile is obviously created by a production and steady release of lactate, which could be measured in the superfusate. As this lactate release is occurring inspite of a sufficient oxygen supply and consumption, it can be concluded that this tissue performs aerobic glycolysis.

Aerobiosis↗
PubMed1989

Fragmentation of biliary calculi by means of extracorporeally generated piezoelectric shock waves.

A new extracorporeal piezoelectric lithotripter was tested for its gallstone disintegration capability. A total of 177 surgically removed gallbladder stones were submitted to piezoelectric shock-wave treatment. Prior to shock-wave application, the diameter, weight, and volume of all the stones and CT density and MR signal intensity of selected stones were determined. After shock-wave application, the chemical composition of the stones was investigated by x-ray diffractometry and/or infrared spectrometry. All the stones (maximum diameter 6-30 mm) were successfully fragmented; calculi with a maximum diameter of 17 mm, a maximum weight of 1800 mg, and a maximum volume of 2 cc were regularly disintegrated into fragments less than or equal to 4 mm. The number of shock waves required correlated most closely with volume (r = 0.82, P less than 0.001), weight (r = 0.81, P less than 0.001) and, to a somewhat lesser degree, diameter (r = 0.62, P less than 0.001). No correlation was found between the chemical composition, CT density, or MR intensity of the calculi and the number of pulses needed for fragmentation.

Cholelithiasis↗
PubMed1989

A Canadian multicenter study with Zaditen (ketotifen) in the treatment of bronchial asthma in children aged 5 to 17 years.

One hundred thirty-eight children with chronic asthma, requiring daily treatment with bronchodilators, took part in a 7-month, double-blind, multicenter clinical study. Patients were randomized into two groups, and after a 1-month baseline, were administered Zaditen (ketotifen), 1.0 mg twice daily, or an identical placebo for a period of 6 months. After 10 weeks of receiving the study medication, bronchodilator use was reduced or stopped. In the Zaditen-treated group, 60% of the children taking theophylline were able to stop its use completely, compared to 34% of the patients taking placebo (p less than 0.05). Of the patients who were unable to stop taking theophylline, the Zaditen-and placebo-treated groups recorded average dosage reductions of 62% and 26%, respectively. These differences were statistically significant (p less than 0.05). Thus, a high percentage of patients in the placebo-treated group maintained asthma symptom control with theophylline, whereas most of the Zaditen-treated patients could stop using this medication. Although pulmonary function readings improved in both groups, those patients taking Zaditen demonstrated earlier improvement and greater changes from baseline. Significant differences (p less than 0.05) in favor of Zaditen were found for reduction of concomitant medications, patient's global evaluation, physician's clinical evaluations, incidence of emergency room visits for asthma, and upper respiratory tract infections. No unexpected side effects were observed. It is concluded that Zaditen is an effective medication for long-term control of asthma in children.

Adolescent↗
PubMed1989

Tissue reactions under piezoelectric shockwave application for the fragmentation of biliary calculi.

The tissue reactions that occurred during piezoelectric shockwaves for the fragmentation of biliary calculi were investigated in 10 surgically removed stone containing human gall bladders and in acute (six dogs) and chronic (six dogs) animal experiments. Before and after shockwave (500, 1500 or 3000) in the anaesthetised dogs, computed tomography (CT), magnetic imaging (MRI) and laboratory tests were done; treatment was carried out under continuous ultrasonographic control. Shockwave applications to the human gall bladders resulted in disintegration of the stones with no macroscopically or microscopically detectable tissue changes. In acute animal experiments, small haematomas were observed in all six animals at surfaces, but also inside the liver and gall bladder (max diameter 25 mm). Perforation or intra-abdominal or pleural bleeding did not occur. In chronic experiments, no macroscopic, and only slight microscopic residual lesions (haemosiderin deposits) were seen three weeks after shockwave. In almost all instances, the lesions were detected by CT, MRI, and ultrasonography, while laboratory tests were negative.

Animals↗
PubMed1988

Functional morphology of the ommatidia in the compound eye of the moth, Antheraea polyphemus (Insecta, Saturniidae).

The fine structure of the superposition eye of the Saturniid moth Antheraea polyphemus Cramer was investigated by electron microscopy. Each of the approximately 10,000 ommatidia consists of the same structural components, but regarding the arrangement of the ommatidia and the rhabdom structure therein, two regions of the eye have to be distinguished. In a small dorsal rim area, the ommatidia are characterized by rectangularly shaped rhabdoms containing parallel microvilli arranged in groups that are oriented perpendicular to each other. In all other ommatidia, the proximal parts of the rhabdoms show radially arranged microvilli, whereas the distal parts may reveal different patterns, frequently with microvilli in two directions or sometimes even in one direction. Moreover, the microvilli of all distal cells are arranged in parallel to meridians of the eyes. By virtue of these structural features the eyes should enable this moth not only discrimination of the plane of polarized light but also skylight-orientation via the polarization pattern, depending on moon position. The receptor cells exhibit only small alterations during daylight within the natural diurnal cycle. However, under illumination with different monochromatic lights of physiological intensity, receptor cells can be unbalanced: Changes in ultrastructure of the rhabdomeres and the cytoplasm of such cells are evident. The effects are different in the daytime and at night. These findings are discussed in relation to the breakdown and regeneration of microvilli and the influence of the diurnal cycle. They are compared with results on photoreceptor membrane turnover in eyes of other arthropod species.

Animals↗
PubMed1986

[The history of pharmaceutical science. 15. Development of pharmacy at the University of Greifswald between 1903 and 1968].

The paper is the first part of an extensive investigation about the development of pharmaceutical science at a university. The major purpose of this research is to show separately aspects of scientific organisation, the personel structure, the material-technical premise, teaching and research. Studies of the development of scientific organisation structures have carried out about several centuries, from the first teaching in the medical faculty in 1559, from the establishment of the section of pharmaceutical chemistry in the chemical institute in 1903, the foundation of the Institute of pharmaceutical chemistry in 1946 up to the "Department of Pharmacy Greifswald" in 1968.

Chemistry, Pharmaceutical↗
PubMed1986

A high density field population of mixed phases (solitaria and gregaria) of armyworm (Spodoptera exempta) caterpillars in Kenya.

An unusual type of mass propagation ("outbreak") of armyworms (Spodoptera exempta) was found during the rainy season in the highlands of central Kenya. In a very small area it had a high density of individuals but - unlike normal outbreaks - it comprised a continuity of different developmental stages from young caterpillars to moths. The older caterpillars were of phase solitaria or gregaria together with numerous individuals of intermediate forms. From their different ages it is improbable that they all came from parental moths having arrived together. The finding of such type of outbreak seems of interest for understanding the development of the huge uniform outbreaks of this species frequently occurring in East Africa.

Animals↗