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Biomedical subjects

B Wilhelm

Publications and source records attributed to B Wilhelm.

At least 19 recordsLinked to original sources

[The common occurrence of osteoarthritis and osteoporosis and the value of markers of bone turnover].

OBJECTIVE: Increasing bone mineral density (BMD) has been found in several studies in patients with osteoarthritis. Therefore, many clinicians deny the simultaneous occurrence of osteoporosis (OP) and osteoarthritis (OA). Because of our clinical impression however, we suggested that we have to consider a common occurrence. Furthermore, the value of markers of bone turn over with a view to early diagnosis of OP and or as an assessment for bone metabolism in OA is still a matter debate and their clinical use has not been clearly defined in the management of the individual patient. METHOD: The BMD of the lumbar spine and the proximal femur of 119 OA patients (83 postmenopausal female patients aged 50-83 and 35 male patients aged 36-86 years) who subsequently required hip or knee replacements, but were otherwise healthy, were measured by dual energy X-ray absorption (DXA), Hologic QDR-2000. We also measured biochemical markers of bone turn over, i. e., CICP, ICTP, DPD, PTH, estrogen, testosterone, bAP, hydroxy vitamin D and the normal blood count. RESULTS: There was a high occurrence of a low BMD among the patients. A total of 28.9% of women were affected by OP and 52.9% by osteopoenie. This reflects the normal distribution of OP in the female population. Of the male patients 20% had OP and 38.8% osteopoenie. This is astonishing high. Age proved to be a significant factor in the degree of BMD. An association between disuse osteoporosis and degree of BMD in the OA affected joint could not be proven. The use of the biochemical markers for an earlier diagnosis or to assess bone metabolism in OP and OA was not possible. CONCLUSION: We can not support the hypotheses that OA prevents OP. Moreover, the occurrence of OP in our study reflected the incidence of OP in the average female and the astonishingly high incidence in the male population; however does not mean that the two conditions are mutually exclusive. We did not find that the biochemical markers of bone turn over could deliver additional information with respect to bone metabolism and an earlier diagnosis of OP.

Absorptiometry, Photon↗

Establishing of two in vitro models of epithelial cells from the apocrine secreting rat coagulating gland.

Apocrine secretion is an alternative export pathway for proteins and was described especially for accessory sex glands of rodents and men. This mechanism is not as well characterized as the classical merocrine (eccrine) export. In the rat coagulating gland both secretion modes were observed, and several proteins were identified to be released by these two pathways. To obtain more data on the apocrine secretion mode, we established two culture models of the rat coagulating gland: primary epithelial cells and an organ culture system. The in vitro models were characterized with immunocytochemistry, electron microscopy and RT-PCR. The polarity of primary and passaged epithelial cells (passage 8) was proven by the detection of occludin, E-cadherin and beta-actin. The gland tissue pieces showed good maintenance after 1-week culture. Finally we demonstrated that the epithelial cells of both culture models are still expressing and producing apocrine and merocrine proteins. Using these two culture models for the rat coagulating gland, it is now possible to initiate studies on the apocrine secretion mechanism in vitro.

Animals↗

Identification and characterization of neutral endopeptidase (EC 3. 4. 24. 11) from human prostasomes--localization in prostatic tissue and cell lines.

BACKGROUND: An antibody directed against a 100 kDa protein was immunoselected from a polyvalent antiserum against human prostasomes. The antibody as well as biochemical characteristics of the respective antigen were used to study the structural relationship of the latter with prostate membrane specific antigen (PMSA), another 100 kDa membrane protein of the prostate. METHODS: The isolated purified 100 kDa protein was characterized by tryptic degradation, aminoacid-sequencing and mass spectroscopy peptide-fingerprinting as well as mono-saccharide analysis and lectin binding and identified as a prostasomal neutral endopeptidase (NEP, EC 3.4.24.11). Immunohistochemistry, immunoelectron microscopy, in situ hybridization, and RT-PCR were performed to analyze the expression and distribution of the protein in normal and malignant human prostatic tissues and cell lines. RESULTS: Prostatic NEP, which has no relationship with PMSA, is a glycosylated, integral membrane protein type II. The prevalent glycosyl residues are NeuNAc, GlcNAc, GalNAc, Gal, Man, Fuc. NEP-mRNA is expressed in human prostatic epithelial and some stromal cells. NEP-immunoreactivity is strong in normal prostatic epithelium and confined to the apical plasma membrane. During apocrine secretion, the enzyme is released from the secretory cells, contributing to the formation of prostasomes. In prostate cancer specimens, immunoreactivity of apical plasma membranes is lost, while generalized cytoplasmic immunoreactivity develops. CONCLUSIONS: Prostatic secretory cells contain a membrane-bound, highly glycosylated neutral endopeptidase which is restricted to the apical plasma membrane. The enzyme is released from the cells in an apocrine fashion and contributes to the formation of prostasomes. In prostate cancer cells a preferential cytoplasmic localization is observed, pointing to alterations in intracellular targeting.

Amino Acid Sequence↗

Effects of zinc chloride on glutathione and glutathione synthesis rates in various lung cell lines.

Zinc-mediated toxicity has been linked to cellular glutathione (GSH) contents. In this study, effects of zinc on cellular GSH content, glutathione reductase (GR) activity, and GSH synthesis were investigated. In all cell lines tested, decreases in cellular GSH content and GR activity as well as an increase in oxidized glutathione (GSSG) were found after incubation of cells with zinc chloride. These effects were dose- and time-dependent. Changes in GR activities were earliest affected and were most marked compared with the other parameters examined. Decrease of enzyme activity was not due to a decrease in the cosubstrate NADPH. In A549 and L2 cells, initial increases in GSH synthesis rates occurred up to about 175% of control. Later, GSH synthesis decreased to levels below controls. In 16Lu cells, GSH synthesis decreased after 2 h of zinc exposure. No transient increase was found in this cell line. Measurement of ATP content did not show any influence of zinc on cellular ATP. Lactate dehyrogenase leakage, a marker of a clear cytotoxic effect, occurred after 6 h of zinc treatment in the non-malignant cells examined, and after 16 h in malignant A549 cells. We assume the inhibition of GR activity and the associated increase of GSSG could possibly represent a main zinc-mediated toxic cellular effect.

Animals↗

Daytime variations in central nervous system activation measured by a pupillographic sleepiness test.

Pupil size is regulated exclusively by the autonomic nervous system, and in darkness is proportional to the level of central sympathetic tone. Spontaneous pupillary movements, while at rest in darkness and quiet, were recorded for a period of 11 min, using infrared video pupillography. Thirteen young adults took part in a 30-h experiment lasting from 08.00 h to 14.00 h on the following day. Pupillographic testing and completion of a self-rated scale for the estimate of sleepiness were repeated every two hours. Pupillary unrest index (PUI), as a measure of pupil size instability associated with daytime sleepiness, showed the lowest values at 09.00 h, when pupil size was found to be maximal, and 23.00 h. During the course of the day, amplitude spectrum < or = 0.8 Hz and PUI showed increasing values during the afternoon hours, followed by a decrease during the evening. Daytime variations in the pupillary unrest index in healthy normal subjects were found to be positively correlated with the level of alertness. These findings are similar to the daytime variations found by the MSLT (multiple sleep latency test) in young adults.

Adult↗

[Automated swinging flashlight test in patients with optic nerve diseases].

AIM OF THE STUDY: The swinging flashlight test is an objective method to diagnose a lesion of the anterior visual pathways. However, errors and faults may easily alter the test's results. Hence, the value of the swinging flashlight test depends highly on the examiner's skills. Therefore an automated and objective procedure was developed which is independent from the examiner. METHODS: A binocularly measuring instrument adapted for video pupillography was supplied with two arrays of light emitting diodes in front of each eye of the subject. By means of this illumination, pupillary light reflexes are elicited alternately. Pupil size is registered continuously, and after artifact elimination, the response amplitudes of the pupils are determined as a mean of right and left pupil. Responses elicited via right and left eye are compared. By varying the stimulus intensity it is possible to measure the amount of the relative afferent pupillary defect. The procedure was tested in 31 patients with optic nerve disorders. RESULTS: The measurements were easily feasible, stable and reliable. Correlation between the relative afferent pupillary defect detected manually by grey filter compensating and with the automated procedure proved to be high. Both variables correlated highly significant with a Spearman rank coefficient of 0.65. If the clinical test is regarded as the golden standard, the automated swinging flashlight test is able to detect 85% of the relative afferent pupillary defects > or = 0.3 logE and 94% of the defects > or = 0.6 logE. CONCLUSION: The automated swinging flashlight test can be recommended to exclude influences by the examiner or if the exact amount of the relative afferent pupillary defect is desired, e.g. when monitoring therapeutic effects in optic nerve diseases. Furthermore, an automated swinging flashlight test could serve as a screening test.

Adult↗

Purification and characterization of macrophage migration inhibitory factor as a secretory protein from rat epididymis: evidences for alternative release and transfer to spermatozoa.

BACKGROUND: The cytokine macrophage migration inhibitory factor (MIF), originally described as a T cell product, has recently been identified to mediate cellular interactions in several endocrine organs. Western blots analysis of rat epididymal homogenates using an anti-MIF antibody indicated the presence of substantial amounts of an immunoreactive protein with the apparent Mr of 12 kDa. Our study aimed to characterize the molecular nature of this immunoreactive factor. MATERIALS AND METHODS: The purified 12 kDa protein and a cloned cDNA fragment were characterized by sequence analysis. Furthermore, expression pattern and localization of the 12 kDa protein were investigated using in situ hybridization, immunohistochemistry, immunoelectron microscopy, and western blots experiments on epididymal sections, isolated epididymal vesicles, and outer dense fibers from spermatozoa. RESULTS: The N-terminal amino acid sequence analysis over 10 amino acids revealed a 100% homology of the 12 kDa protein to the N-terminus of the cytokine MIF. These data were confirmed by sequence analysis of a reverse transcription polymerase chain reaction (RT-PCR) amplified cDNA fragment from rat epididymis, which also showed complete homology to the MIF cDNA sequence. MIF protein and mRNA were localized in the epithelial cells of the epididymis in a regional distribution manner, with the expression maximal in the caput. Immune cells were not labeled. MIF is the first classical cytokine identified to be expressed by the epididymal epithelial cells. Immunoelectron microscopy detected MIF immunoreactivity in the cytoplasm, with no reaction visible in the Golgi complex and the cisternae of the endoplasmic reticulum. At the apical cell surface, MIF accumulated in stereocilia and vesicles that were pinched off from the plasma membrane. MIF detection in vesicles isolated from epididymal secretion together with the lack of a N-terminal signal sequence for translocation in the endoplasmic reticulum strongly suggested a nonclassical secretion mode. Furthermore, MIF was identified as a new component of the outer dense fibers (ODF), a cytoskeletal element of the mid- and principal piece of the sperm tail. CONCLUSION: The cytokine MIF was identified in substantial amounts in the epithelial cells of rat epididymis and in the outer dense fibers of rat epididymal spermatozoa. Our results indicate a nonclassical secretion mode for MIF and suggest a cell-to-cell transfer of MIF via vesicles to the sperm cells.

Animals↗

Naso-temporal asymmetry and contraction anisocoria in the pupillomotor system.

BACKGROUND: Differences between the pupillomotor sensitivity of nasal and temporal retinal hemifields may contribute to the relative afferent pupillary defect (RAPD) seen in optic tract or pretectal lesions. To understand the architecture of the pupillary pathway, it is necessary to know the size and the prevalence of such naso-temporal differences and also of contraction anisocoria (unequal direct and consensual pupillary responses) in normal individuals. The results of previous studies have been only partially consistent. METHODS: We registered the direct and consensual pupillary light reactions in both central retinal hemifields of 42 healthy subjects by means of IR video pupillography. Stimuli were generated under mesopic conditions on a computer screen as half-circles with 4.6 cd/m2 and 10 deg radius. Stimulus duration was 200 ms with a stimulation interval of 4 s. RESULTS: The nasal retina was significantly more sensitive than the temporal retina, and the direct pupillary reactions were significantly larger than the consensual reactions. For the nasal retina, direct pupillary reactions exceeded the consensual reactions, whereas there was nearly no difference between direct and consensual reactions for the temporal retina. CONCLUSION: RAPD in optic tract damage or pretectal lesions cannot be explained by the only slightly more sensitive nasal retina. Considerably more input would be needed from the contralateral than from the ipsilateral retina into the optic tract. The nearly equal direct and consensual pupil reactions when stimulating the temporal retina suggest an input of temporal retina to both sides of the pretectum. Such a crossing of temporal fibres may take place in the chiasm.

Adult↗

Spontaneous fluctuations in pupil size are not triggered by lens accommodation.

Fluctuations in pupil size and lens accommodation are measured concurrently under open loop conditions, constant illumination and far fixation. In 12/17 trials no correlation was measured between the fluctuations in pupil size and lens accommodation. For the remaining 5/17 trials no lag was observed between the changes in pupil size and lens accommodation indicating that this correlation does not arise as a consequence of a near response. These observations suggest that under conditions of constant illumination and far fixation, the supranuclear centers controlling the near response are not active.

Accommodation, Ocular↗

The genomic organization of the mouse CD94 C-type lectin gene.

The mouse natural killer (NK) gene complex is located on chromosome 6 and contains a number of genes encoding C-type lectin receptors which have been found to regulate NK cell function. Among these are CD94 and four NKG2 genes. Like its human counterpart, the mouse CD94 protein associates with different NKG2 isoforms and recognizes the atypical MHC class I molecule Qa-1b. Here, the genomic organization of the mouse CD94 gene was determined by analysing a BAC clone containing the CD94 gene. The mouse CD94 gene contains six exons separated by five introns. Exons I and II encode the 5' untranslated region (UTR) and the transmembrane domain. Exon III encodes the stalk region and exons IV-VI encode the carbohydrate recognition domain (CRD). Furthermore, we cloned and sequenced the CD94 promoter region, and putative regulatory DNA elements were identified. Further studies on the CD94 promoter region may help to elucidate the restricted expression pattern of CD94 in NK cells and a subpopulation of T cells.

Alternative Splicing↗

Effect of zinc chloride on GSH synthesis rates in various lung cell lines.

Zinc toxicity has been linked to decreased reduced glutathione (GSH) and increased oxidized glutathione (GSSG) contents, which might be caused by a GSSG reductase inhibition by zinc. In this study we investigated zinc effects on GSH synthesis rates in various lung cell lines by thin-layer chromatography after (35)S-cysteine incorporation. Two alveolar epithelial cell lines (A549 and L2) and two human fibroblast-like lung cell lines (11Lu and 16Lu) were used in this study. Equipotent protein synthesis inhibition for the different cell lines was reached after 2 h (L2, 11Lu), 3 h (16Lu), and 4 h (A549) zinc exposure (15-200 microM) to cells. Here GSH depletion and GSSG increase in A549 cells were markedly lower than in the other cell lines tested. Incorporation of cysteine (Cys) into GSH was not different in the cell lines tested, while 11Lu cells only demonstrated a decrease of newly synthesized GSH after 1 h of (35)S-Cys exposure when cells were exposed to zinc. Only 11Lu cells showed a markedly decreased Cys availability as compared with the other cell lines. In all cell lines the availability of Cys was not affected by exposure to zinc. No compensating increase in GSH synthesis rates was found after zinc-mediated cellular GSH depletion.

Carcinoma, Non-Small-Cell Lung↗

Laboratory, clinical, and kindergarten test of a new eccentric infrared photorefractor (PowerRefractor).

PURPOSE: Photorefraction is a convenient way to determine refractive state from a distance. It is, therefore, useful for measuring infants and noncooperative subjects. However, its reliability (or precision) and accuracy (or validity) has been questioned. In a study in subjects without cycloplegia, we have tested whether, after complete automatization, eccentric photorefraction at a 1-m distance can be as reliable as a common autorefractor. METHODS: In a laboratory study of 15 student subjects without the use of cycloplegia (30 eyes, refractive errors ranging from -6 D to +6 D), age 25 to 31 years, the photorefractive measurements were compared with spectacle prescriptions. In a clinical study, photorefraction, autorefraction, and subjective refraction were performed in 40 patients without cycloplegia (refractive errors ranging from -4 D to +4 D), most of them with various ocular pathologies. Subjective refractions were obtained by an experienced clinical ophthalmologist but were not accessible to the examiner who used the two refractors. Visual acuity was 20/20 or better except for five subjects. Ages ranged from 6 to 75 years. In the kindergarten screening study, 108 children aged 3 to 6 years were screened for refractive errors. RESULTS: In the laboratory study, it was found that the mean difference between spectacle prescription and PowerRefractor measurements was < 0.6 D for spheres and below 0.4 D for cylinders. In the clinical study, data were obtained by all three procedures in 78 eyes. The photorefractor and the autorefractor performed similarly for spheres (mean absolute dioptric difference between refractor and subjective measure: 0.593 D and 0.696 D) and cylinders (mean absolute dioptric differences: 0.399 D and 0.389 D). However, the photorefractor was superior with regard to the measurement of the magnitude and axis of astigmatism (mean weighted difference between objective and subjective axis 0.644 D and 0.769 D, respectively). In the kindergarten study, it was found that the PowerRefractor was very convenient to handle. The autorefractor measured more myopic refractions than the PowerRefractor (mean of the left eyes 0.11 +/- 1.1 D vs. 0.62 +/- 0.53 D, p < 0.001). There was no indication that the PowerRefractor failed to detect hyperopia, because all but one child with more than 2 D of hyperopia measured with autorefractor (n = 7) was also hyperopic with the PowerRefractor. Furthermore, presenting an interesting fixation target at a 3-m distance did not cause more hyperopic refractions, indicating that the camera of the PowerRefractor at a 1-m distance was not a significant stimulus to accommodation. CONCLUSIONS: The PowerRefractor was shown to have comparable or slightly better reliability and accuracy than a modern autorefractor; however, it has major advantages over current autorefractors in that it is faster, measures both eyes at once, and gives interpupillary distance, pupil size, and information on the alignment of the eyes at the same time.

Adolescent↗

Zinc toxicity in various lung cell lines is mediated by glutathione and GSSG reductase activity.

In a previous work, it was shown that in cells after a decrease of cellular glutathione content, toxic zinc effects, such as protein synthesis inhibition or GSSG (glutathione, oxidized form) increases, were enhanced. In this study, zinc toxicity was determined by detection of methionine incorporation as a parameter of protein synthesis and GSSG increase in various lung cell lines (A549, L2, 11Lu, 16Lu), dependent on enhanced GSSG reductase activities and changed glutathione contents. After pretreatment of cells with DL-buthionine-[R,S]-sulfoximine (BSO) for 72 h, cellular glutathione contents were decreased to 15-40% and GSSG reductase activity was increased to 120-135% in a concentration-dependent manner. In BSO pretreated cells, the IC50 values of zinc for methionine incorporation inhibition were unchanged as compared to cells not pretreated. The GSSG increase in BSO pretreated cells by zinc was enhanced in L2, 11Lu, and 16Lu cells, whereas in A549 cells, the GSSG increase by zinc was enhanced only after pretreatment with the highest BSO concentration. Inhibition of GSSG reductase in alveolar epithelial cells was observed at lower zinc concentrations than needed for methionine incorporation inhibition, whereas in fibroblastlike cells, inhibition of GSSG reductase occurred at markedly higher zinc concentrations as compared to methionine incorporation inhibition. These results demonstrate that GSSG reductase is an important factor in cellular zinc susceptibility. We conclude that reduction of GSSG is reduced in zinc-exposed cells. Therefore, protection of GSH oxidation by various antioxidants as well as enhancement of GSH content are expected to be mechanisms of diminishing toxic cellular effects after exposure to zinc.

Buthionine Sulfoximine↗

Pupil perimetry using M-sequence stimulation technique.

PURPOSE: M-sequence stimulation technique allows mapping of the retinal function by multifocal electroretinographic (ERG) recordings. However, the information provided about visual field is limited to retinal function. Optic nerve diseases and diseases of the higher visual pathways usually show normal multifocal ERGs. Using pupillary responses instead of the electrical retinal responses might enhance the diagnostic possibilities of this system. The problems of local ERG recordings are very similar to those encountered in pupil perimetry: Local stimuli have to be dim to avoid or at least reduce stray-light responses. Dim stimuli, close to the absolute threshold, elicit only subtle pupillomotor responses. Therefore, techniques that are able to detect small focal responses are promising. METHODS: Pupillography was done by means of an infrared video camera and real time image processing (50 Hz) using a custom-designed videoboard in a personal computer (486). Recording conditions: The stimulus was presented on a monitor (75 Hz) in 26 cm distance from the patient's eyes. It contained 37 hexagons in a 25 degrees visual field. Each element changed between black (1.6 cd/m2) and white (160 cd/m2) after a binary M-sequence independently from other elements. Four thousand ninety six different stimulus pictures of 120-msec duration were shown during a single pupillogram recording. Thirty-seven local pupillograms were calculated in a cross-correlation of stimulus sequence and the pupil diameter. RESULTS: The pupillomotor fields in normals showed a shape and sensitivity distribution as known from conventional pupil perimetry techniques. Artificial paracentral scotomas (5 degrees) created by masking different locations could be demonstrated convincingly. Even in patients with optic nerve lesions it was possible to demonstrate visual field defects. CONCLUSIONS: Pupil perimetry using the M-sequence technique is a promising method of objective perimetry that may find its entrance into clinical application.

Adult↗

Simultaneous apocrine and merocrine secretion in the rat coagulating gland.

The coagulating gland of the rat synthesizes two prevalent secretory proteins (transglutaminase and 115 K) that are discharched in a different manner, one being secreted in an apocrine fashion (transglutaminase) and the other one in a merocrine way (115 K). Differences in the intra- cellular pathway and the release of either protein were studied using immunofluorescence on semithin sections, immunoelectron microscopy of preembedding-processed chopper sections and postembedding-processed ultrathin sections of rat coagulating gland. Immunohistochemical staining using an anti-transglutaminase antibody resulted in dense labeling of the cytoplasm of secretory cells and their apical blebs, whereas the cisternae of the rough endoplasmic reticulum and the Golgi apparatus were completely unlabeled. When, on the contrary, the anti-115 K antiserum was used, dense labeling of the cisternae of the rough endoplasmic reticulum, the Golgi apparatus, and the secretory granules was seen. Intraluminal secretion was also labeled, but the secretory blebs remained unlabeled. Our findings show that, in the coagulating gland of the male rat, the two secretory proteins studied are processed in parallel, but at completely different intracellular pathways. They are released via different extrusion mechanisms. Transglutaminase is synthesized outside the endoplasmic reticulum, reaches the apical cell pole by free flow in the cytoplasm, and is released via apocrine blebs, the membranes of which appear to be derived from the apical plasma membrane. The protein 115 K, on the other hand, follows the classic route, being synthesized within the cisternae of rough endoplasmic reticulum, subsequently glycosylated in the Golgi apparatus, and released in a merocrine fashion. The mutual exclusion of the two secretory pathways and the regulation of the alternative release mechanism are still unresolved issues.

Animals↗

Serum albumin as a potential carrier for the apocrine secretion of proteins in the rat coagulating gland.

A protein of 66k was purified to homogeneity from the total secretion of rat coagulating gland. Its close structural relationship to serum albumin was demonstrated by N-terminal amino acid sequence analysis, proteolytic fingerprinting and Western blotting studies using polyclonal antibodies raised against the 66k protein and rat serum albumin. Immunofluorescence staining showed that the 66k protein was localised in the cytoplasm of coagulating gland epithelial cells from which it is released via apocrine blebs. Performing immunoelectron microscopy, the 66k protein was by no means detectable in the endoplasmic reticulum and the Golgi apparatus. Reverse transcription-PCR, Northern blotting studies and in situ hybridisation experiments demonstrated that mRNA of albumin is not expressed by coagulating gland epithelial cells. Therefore, intravascular albumin should be transferred into the epithelial cells of the rat coagulating gland followed by secretion via aposomes. Furthermore, overlay blots proved that the 66k protein binds to the apocrine proteins carbonic anhydrase II and secretory transglutaminase and vice versa. In contrast, no binding was evident to the merocrine 115k protein and to cytoplasmic resident proteins e.g. lactate dehydrogenase. These findings point to the assumption that serum albumin taken up from extracellular sources could function as a selective carrier for cytoplasmic proteins destined for apocrine secretion.

Animals↗