Biomedical subjects
J Hensel
Publications and source records attributed to J Hensel.
Low-frequency modulation of the 2f1-f2 distortion product otoacoustic emissions in the human ear.
Low-frequency masking is a recent clinical procedure for the differential diagnosis of sensory hearing loss. Currently this requires the recording of the phase-dependent masked subjective threshold, which is time consuming and not always accurate. As an objective method, the recording of modulated distortion product otoacoustic emissions (DPOAEs) can be performed continuously, and with better frequency specificity. Results of measurements of the low-frequency modulated two-tone DPOAE 2f1-f2 in the human ear, and its dependence on various acoustic parameters, are presented here for the first time. Similar to the masked hearing threshold, the pattern of the phase-dependent modulated DPOAEs displayed two minima, at the phases of maximal rarefaction and condensation, respectively, with a latency of about 4 ms (suppressor frequency 32.8 Hz). The smaller dip, at maximal condensation, appeared only for a high suppressor level, and for a low level of the primary tone f2. The modulating effect measured for the primary frequencies f1 = 2.5 kHz and f2 = 3 kHz, decreased for 4 and 4.8 kHz, and vanished for 5 and 6 kHz. The results are discussed using a cubic distortion model based on the Boltzmann function for mechano-electrical transduction of the hair cells. The saturation behavior of the increase of the DPOAE level at different phases is compared with the growth rates of the DPOAE level in normal hearing and in sensory hearing loss.
Localization of the palmitoylation site in the transmembrane protein p12E of Friend murine leukaemia virus.
Friend murine leukaemia virus complex was propagated on murine cells in the presence of [9,10-3H]palmitic acid. Virus particles were harvested from the culture supernatant and lysed with detergents. The viral transmembrane protein, p12E, was isolated from the lysates by size-exclusion chromatography and purified by narrowbore reverse-phase HPLC. Analysis of the purified product by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) revealed that the protein is palmitoylated carrying one fatty acid residue. The radiolabelled fatty acid was released by hydroxylamine treatment at pH 7, indicating that acylation occurred via a thioester linkage. For allocation of the acylation site, p12E was digested with trypsin. The resulting peptides were either directly subjected to MALDI-TOF-MS or fractionated by microbore reverse-phase HPLC prior to mass spectrometry. The results revealed that p12E of Friend murine leukaemia virus is acylated at a cysteine residue situated at the C-terminal side of the putative transmembrane anchor of the polypeptide. Fatty acid analysis of the purified acylpeptide demonstrated that p12E carries almost exclusively palmitic acid.
Studies on the effect of tunicamycin on erythrocytic stages of Plasmodium falciparum.
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[Biosensors for the determination of phenol and benzoate on the basis of Rhodococcus cells and enzyme extracts].
An amperometric biosensor for determination of phenol, cresol, benzoate and 2-methyl-4-chlorophenol using Rhodococcus-cells and enzyme extracts of Rhodococcus has been developed. The influence of cultivation of Rhodococcus-cells and preincubation of the biosensor with desired substrate on sensibility and specificity was been investigated. In relation to cultivation and preincubation the Rhodococcus sensor was high specific to benzoate or phenol and cresol. A linear range was obtained for phenol and benzoate up to 80 mumol and for 2-methyl-4-chlorophenol up to 400 mumol. The biosensor using enzyme extracts show a higher specificity, it is but necessary NADPH. A further disadvantage is the little measuring range of this sensor.
Kinetic studies of phenol degradation by Rhodococcus sp. P1. I. Batch cultivation.
Rhodococcus sp. P1 utilizes phenol as the sole carbon and energy source via the beta-ketoadipate pathway. In batch cultivation, concentrations up to 2.8 g.l-1 phenol were degraded. The highest values for the specific growth rate of 0.32 h-1 were obtained at concentrations near 0.25 g.l-1. At higher concentrations, substrate inhibition was observed, characterized by increases in lag phase and decreasing growth rates. A mathematical expression was proposed to fit the kinetic pattern of phenol inhibition on the specific growth rate mu: [formula: see text] Nomenclature: K- Exponent of the inhibition function, Ks- Monod saturation constant, g.l-1, KI- Inhibition constant, g.l-1, S- Substrate concentration in culture broth, g.l-1, So- Initial substrate concentration, g.l-1, Y- Yield constant, g cell dry mass.g substrate-1, mu- Specific growth rate, h-1, mu max- Maximum growth rate, h-1.
Kinetic studies of phenol degradation by Rhodococcus sp. P1. II. Continuous cultivation.
The degradation of phenol by Rhodococcus sp. P1 was studied in continuous culture systems. The organism could be adapted by slowly increasing concentration, step by step, up to 30.0 g.l-1 phenol in the influent. The degradation rate reached values of about 0.3 g.g dry mass-1.h-1. Large step increases in phenol concentration and addition of further substrates (e.g., catechol) were tolerated up to a certain concentration. With increasing dilution rate and increasing inlet phenol concentration the stability of the system decreased. Nomenclature: D--Dilution rate, h-1, Dc--Critical dilution rate, h-1, Dx--Yield, g dry mass.l-1.h-1, Ks--Monod saturation constant, g.l-1, S--Growth-limiting substrate concentration in culture broth, g.l-1, SR--Growth-limiting substrate concentration in feed, g.l-1, mean--Biomass concentration in culture broth, g.l-1, YS--Yield constant, g cell dry mass.g substrate-1, mu--Specific growth rate, h-1, mu max--Maximum growth rate, h-1.
[Porphyria cutanea tarda and lupus erythematosus].
We observed three patients with lupus erythematosus and porphyria cutanea tarda manifesting itself simultaneously or subsequently. The possible coincidence of the two diseases might be the consequence of immunological communities indicated on the assumption of a genetically coined hepatic uroporphyrinogen decarboxylase defect. The treatment of the lupus erythematosus can be performed according to corresponding observations of the course according to general acknowledged principles including the administration of cytostatic drugs, if the chloroquine phosphate therapy which is clearing up the porphyria cutanea tarda is beginning with low dosages. The fluorescence of the fresh kidney bioptate under long-wave UV-light in porphyria cutanea tarda is referred to for the first time.
[Urine proteins in primates].
Protein excretion and protein fractions either according to their molecular mass or with immunological techniques were studied in the spontaneous morning urine of 17 primate species. The total protein concentration in most of the species ranges between 0.01 and 0.2 mg/ml. The pronounced proteinuria (4 mg/ml) in some south american species (Callithricidae) seems to be remarkable. By using immunoprecipitation (LC-Partigen plates), albumin could be detected in most species, alpha 1-microglobulin in some, and transferrin in few of the species. After electrophoretic separation on pre-cast 1D-micro- SDS-PAA gradient gels (8-25%, semi-automatic Phast-System) followed by CBB R-350 or silver stain respectively, in most species a protein pattern similar to human urine could be observed. As our results show, urine analysis is a suitable tool for noninvasive investigations in primates.
[Computer-assisted video processing of Phast gels with ELBA].
Referring to one-dimensional micro electrophoresis-gels, produced at the division of nephrology (Klinikum Göttingen) by using the Phast-System (Pharmacia, Freiburg), the ELBA-program for image evaluation of electrophoretic gels (interactive systems, Heidelberg) was investigated. The digital image, obtained with a computer-controlled video-camera, can be stored up in a personal computer. Independend of time, the digitized data may be retrieved and utilized for evaluation of specific urinary protein patterns. Changes in intensity and constellation of the protein patterns, which may occur during the progress of a disease, can be figured directly in one graphical plot. Therefore, any urinary protein pattern of one or a number of gels can be exactly compared to each other in a short time.
[Pregnancy in patients with visceral lupus erythematosus, with special reference to kidney involvement].
Of 44 female patients with lupus erythematosus visceralis after and with manifestation of the disease, respectively, in eight women ten pregnancies developed, out of them three viable births between the 33rd and 40th week of pregnancy, one stillbirth in the 37th week of pregnancy, one miscarriage in the IIIrd month of pregnancy and five interruptions of pregnancy. It is reported on the course of the disease and pregnancy of five women, taking into particular consideration the lupus nephritis. With the help of the literature and on the basis of own experiences course of the lupus erythematosus visceralis and lupus nephritis during pregnancy, the influence of the lupus erythematosus visceralis on pregnancy and development of the child, peculiarities of the treatment of lupus erythematosus visceralis during pregnancy as well as questions of prevention and interruption of pregnancy are discussed. Finally is tried to draw universal conclusions.
[Observations on the incidence of myocardial infarct with regard to the external environment].
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[Morphologic studies on the occurrence of HBs antigen in liver cirrhoses, epicirrhotic and pure cancers in a large autopsy sample].
1063 hepatic cirrhoses, 138 epicirrhotic carcinomas, and 138 carcinomas without cirrhosis from the autopsy material of the Dresden region obtained from 1970 to 1979 were examined for the occurrence of HBsAg by means of reclassification and after-staining of the documented section material with orcein staining according to Shikata. The portion of the post-B-hepatic cirrhoses of the liver was 95 (8.9 per cent of the total material). In epicirrhotic carcinomas a HBsAg-containing cirrhotic portion was identified in 14 cases (10.1 per cent), whereas hepatic tissue of carcinomas without cirrhosis never showed HBsAg. A relation between the activity degree of the hepatic cirrhosis and the quantity and distribution of HBsAg could not be established. The found out numbers (about equally frequent occurrence of HBsAg in hepatic cirrhosis and epicirrhotic carcinomas, no identification in the hepatic tissue of carcinomas without cirrhosis) reveal that the thesis of a hepatocarcinogenic effect of the hepatitis B virus cannot be supported by the histologic identification of HBsAg in our investigational material. The possibility of confusion of ground-glass hepatocytes with liver oncocytes in the HE-stained section material of the autopsy material is pointed out.
[Wegener's granulomatosis with pronounced kidney involvement].
It is reported on the course of histologically ascertained Wegeners' granulomatosis in 4 patients. After initial affection of the upper respiratory tract in form of necrotizing and granulomatous inflammations in all cases a generalisation of the disease with above all early and severe participation of the kidneys developed. Maximum acceleration of sedimentation, C-reactive protein, anaemia, leucocytosis, eosinophilia, thrombocytosis, enlargement of the number of alpha 2-globulins, increase of creatinine, proteinuria, erythrocyturia and leucocyturia are the most frequent pathological laboratory findings, whereas LE-cells, ANF, rheumatoid factor and decrease of the complement never could be proved. By reason of a pathogenic immunoreaction a combined glucocorticoid therapy and immunosuppressive therapy with prednisolone and cyclophosphamide may favourably influence the course of the disease which is otherwise prognostically infaust.
[Bronchial adenoma with uncommon growth (author's transl)].
Report on a bronchial adenoma in the right lobus inferior pulmonalis (autopsy: histological bronchial adenoma from carcinoid type) of uncommon size and with growth till now not described. The tumor was diagnosed clinically and histologically 4 years before death of the patient, but was not operated. The tumor has continuously infiltrated the left atrium cordis via a vena pulmonalis. This case is stressing the decisive importance of the early diagnosis of bronchial adenoma.
[Beginings of the Czechoslovak Medical Society Jan Evangelista Purkynje in Slovakia].
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[50th birthday of Prof. Dr. Juraj Kolesár, M.D., D.Sc].
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