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Biomedical subjects

M Mohnke

Publications and source records attributed to M Mohnke.

7 recordsLinked to original sources
PubMed1996

Effects of varying filter kernel sizes on the image quality of interstitial lung diseases.

PURPOSE: The aim of the study was to optimize the postprocessing of digital luminescence radiographs of interstitial infiltrates of the lung. MATERIAL AND METHODS: Ninety-seven patients with established diseases of the lung parenchyma were examined: 514 pathological details were investigated, using a 200-speed screen-film system and a storage phosphor plate. In digital postprocessing, the size of the filter kernel (S) varied between S 5 and S 70. Based upon 32896 individual evaluations, the image quality was evaluated in multifactorial variance analyses. RESULTS: The digital standards were significantly inferior to the tested screen-film system. The large filter kernel S 70 and the small filter kernels S 5 and S 10, as well as an algorithm for edge enhancement, showed selective advantages in the depiction of nodular or small linear structures. For micronodular and linear structures, kernel sizes of S 20 and S 40 produced equally good results (p > 0.05). CONCLUSION: Whenever optimized postprocessing is involved, storage phosphor radiography is equal to a modern screen-film system and can be substituted for the latter without any loss of image quality; this is especially valid for the imaging of interstitial infiltrates of the lung.

Female↗
PubMed1993

Constant intravenous pentoxifylline infusions in allogeneic marrow transplant recipients: results of a dose escalation study.

An uncontrolled open prospective dose escalation study of daily constant-rate 24-h i.v. pentoxifylline (PTX) infusions was performed in 24 consecutive adult patients with hematologic malignancies undergoing allogeneic BMT. The objective of this study was to determine the maximum tolerable dose and to evaluate steady-state plasma concentrations of PTX and its major active 5-hydroxylated metabolite (MI) with this application route. On each of three dose levels of PTX (10, 15 and 20 mg/kg/day), eight patients were enrolled in this study. The prominent dose-dependent and dose-limiting adverse effect attributable to PTX infusions was moderate to severe nausea and vomiting which occurred on the 15 mg/kg and 20 mg/kg dose levels. In addition, one patient on each of the higher doses developed central nervous system toxicity which manifested as acute obtundation and myoclonias. Monitoring of steady-state plasma concentrations revealed that metabolite MI contributed 70-80% to both active compounds with a dose-dependent increase of parent drug and metabolite MI concentrations. In patients pretreated by high-dose busulfan and cyclophosphamide (CY), steady-state plasma concentrations of metabolite MI were significantly increased on all dose levels over those of patients who received total body irradiation and CY as a preparative regimen. Furthermore, impairment of excretory liver function led to significant accumulation of parent drug and metabolite MI. In conclusion, constant i.v. PTX infusions in allogeneic marrow transplant recipients are limited by dose-dependent nausea and vomiting with an estimated maximum tolerable dose in the range of 10 mg/kg/day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Endobronchial prosthesis: experience report].

Between January 1988 and December 1990 a total of 84 endobronchial prosthesis were implanted in 55 patients at the Ruhrlandklinik, Essen. Bronchial carcinoma (33/55) was the leading indication for placing an endoluminal stent. Since the technique of implantation seldom leads to serious complications, non-malignant tracheobronchial stenosis and malacia play an increasing role in airway stenting. Implantation was usually performed under general anaesthesia and through rigid tube bronchoscopes with enlarged diameters. Most frequently a flexible silicone stent (Dumon) was used, Montgomery (5/84), Gianturco (5/84), Orlowski (4/84) and Strecker stents were also implanted. The respiratory gain was greatest in central stenosis, 79/84 stents were positioned into trachea or main stem bronchus. Permanent and temporary stenting were performed with success. Dislocation and hemoptysis seldom occur, mucus plugging and incrustation were more frequent complications.

Bronchi↗
PubMed1990

[Distribution pattern of chemical in surface waters as a reflexion of entry pattern--nonvolatile halogenated hydrocarbons].

The concentrations of some nonvolatile halogenated hydrocarbons in surface waters of an industrialized city and its surroundings are given. About 80% of the ballast isomers of hexachlorocyclohexane (alpha, beta and delta BHC) and of DDT and its metabolites are in the range of less than 5 micrograms l-1, whereas ca. 50% of lindane (gamma BHC) were found to be between 5 and 100 micrograms l-1. Starting form the remarks about the differential-diagnostic assessment of environmental concentrations conclusions as to the origin of hexachlorocyclohexane isomers are drawn with the help of their distribution pattern. A high part of the gamma isomer, compared with the ballast isomers means an application (e.g. against mosquitos). This fact may be supported if it coincides with the months typical for such an application. in contrast to this if you have high percentages of alpha, beta and delta hexachlorocyclohexane, it indicates a point source or diffuse inputs of technical BHC. If all four isomers are present on a comparable and very low level this may reflect a remobilization from the sediment.

DDT↗
PubMed1985

[The herbicide propachlor--14 C synthesis, toxicologic problems and methodology studies on the determination of residues in corn, potatoes, water and soil].

Using the synthesized agent propachlor (N-isopropyl-2-chloroacetanilid) labelled with 14C, methodical investigations revealed an extremely high steam volatility not being assumed before because of the low vapour pressure. The method of steam distillation basing on this fact is of universal application to the processing of maize, potatoes, water, and soil, in which propachlor could be quantitatively determined by gas chromatography with a detection sensitivity of 0.02 ppm. Furthermore, this methods allows a simple purification of the raw product of synthesis containing impurities up to 20%. Propachlor codistilled with steam had a purity of more than 99%. Possibly, the high steam volatility of propachlor could have economic and toxicological consequences as to its application (volatilization in the open air with a high atmospheric humidity along with high temperatures). Therefore, an investigation of the steam volatility in the general screening programme for new agents is to be recommended in addition to the usual investigations of steam pressure.

Acetanilides↗