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Biomedical subjects

M Eichhorn

Publications and source records attributed to M Eichhorn.

At least 19 recordsLinked to original sources
PubMed2006

[Agitation and gamma-hydroxybutyrate].

Agitation is a symptom in various disorders. Gamma-hydroxybutyrate (GHB) is often abused because of its stimulating effects. Side effects comprise loss of consciousness, coma, and agitated states. We present a 50-year-old patient with repeated GHB intoxications and abstinent alcohol dependency and a video document showing an agitated state. Diagnostic workup is discussed considering the relevant literature on this topic. Intoxication and dependence on GHB are important entities in the contexts of neurology and psychiatry.

Akathisia, Drug-Induced↗
PubMed2005

[Haemodynamics and diabetic retinopathy].

Diabetic retinopathy is the most common cause of blindness in adults in all industrialised countries. A much better pathophysiological understanding of the disease has been achieved during the last years. There is evidence that a functional deficit in haemodynamics proceeds the morphological changes of the retina. Modern technologies for measuring haemodynamic parameters and their correlation to pathophysiology in diabetic retinopathy are discussed. In the near future it will be possible to use these parameters as an early sign of worsening before morphological changes occur. Measurement of the therapeutic success, e. g., in laser coagulation would seem to be possible.

Blood Flow Velocity↗
PubMed2001

[Tabooisation of a family suicide - possible consequences for relatives].

We introduce the history of a 27 year old woman who lost her mother by suicide at the age of one year. Grown up in the fathers family she came to know the mothers suicide with 14 years. In the same time she had the first contact with the two half-brothers from the mother's side. In this "new" family they discussed open about the suicide, what she perceived as a relief and important for her personal development. The consequences of the rarely studied tabooisation of the family suicide could have impact for the intercourse with the relatives of suicide victims in the clinical work.

Adolescent↗
PubMed1999

Morphological changes of retinal pigment epithelium and choroid in rd-mice.

The sequence of degenerative changes in the retinal pigment epithelium (RPE) and the choroid of retinal degeneration (rd)-mice was studied in correlation with photoreceptor changes. Three weeks to 26-month-old animals were investigated using light and transmission electron microscopy, enzyme histochemistry and quantitative morphology. Changes in the choriocapillaris (CC) were additionally studied by scanning electron microscopy of corrosion cast preparations. In 3-week-old mice, in which most of the outer segments of photoreceptors in the central portion of the retina had disappeared but remnants of the cells were still present, the RPE was enlarged and showed elongated microvilli. In 8-week-old animals, the photoreceptors were completely absent in large areas of the posterior pole region. In these areas the RPE was also completely lost. Quantitative evaluation performed in histological serial sections showed that loss of RPE measured as length of RPE-free Bruch's membrane, continuously increased up to the age of 20 months. In 8-week-old animals, CC adjacent to degenerating RPE showed loss of fenestration. In 10-week-old animals, the CC disappeared in those areas where the RPE was already lacking. The loss of CC increased with increasing age and in 20-month-old animals 5-10% of the entire CC was lacking. Loss of the related arterioles and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d)-positive nerve fibers occurred only in approximately 2-year-old rd-mice. Compared to other animal models, RPE and CC defects in rd-mice are relatively large. The rd-mice might therefore provide a good tool to study factors involved in CC degeneration.

Animals↗
PubMed1999

AlphaB-crystallin in the trabecular meshwork is inducible by transforming growth factor-beta.

PURPOSE: Because in glaucomatous eyes transforming growth factor-beta (TGF-beta) and alphaB-crystallin are increased in the anterior eye segment, the effect of TGF-beta1 and TGF-beta2 on the expression of alphaB-crystallin and its corresponding mRNA was studied in human trabecular meshwork (TM) cells. METHODS: Monolayer cultures of "cribriform" and "corneoscleral" TM cells of 5 human donors (12-73 years of age) were treated with either 1.0 ng/ml TGF-beta1, TGF-alpha2, or 5 X 10(-7) dexamethasone (DEX) for 12 to 96 hours. Induction of alphaB-crystallin and the related mRNA was investigated by western and northern blot analyses. For comparison, human foreskin fibroblasts (HFF) and NIH 3T3 cells were treated in the same way as the TM cells. RESULTS: An increase of alphaB-crystallin mRNA was observed after treatment of TM cells with TGF-beta1 and TGF-beta2, whereas DEX had no effect. In the cribriform TM cells with a high basal level, the enhancement ranged between 2 and 3 times; whereas in the corneoscleral TM cells alphaB-crystallin mRNA increased between 5 and 6 times. Using western blot analysis, the increase of alphaB-crystallin expression in the cribriform TM cells was only small compared with the significant increase in the corneoscleral TM cells. Treatment of HFF and NIH 3T3 cells with TGF-beta did not induce alphaB-crystallin mRNA. CONCLUSIONS: This is the first time to show that alphaB-crystallin is not only induced by stress factors but also by TGF-beta in TM cell cultures. The difference in induction of mRNA and protein seems to be dependent on alphaB-crystallin concentration before treatment.

Aged↗
PubMed1998

High-energy phosphates in the frontal lobe correlate with Wisconsin Card Sort Test performance in controls, not in schizophrenics: a 31phosphorus magnetic resonance spectroscopic and neuropsychological investigation.

In recent years, a number of 31phosphorus magnetic resonance spectroscopy (P-MRS) studies on the frontal lobe of schizophrenics have been performed, reporting alterations of phospholipids and high-energy phosphates. Deicken et al. (1994b) recently found positive correlations between left frontal phosphomonoester% (PME%) levels and the performance of a specific frontal lobe task, the Wisconsin Card Sorting Test (WCST), in schizophrenics. In the present paper, the correlations between phospholipids and high-energy phosphates in the frontal lobe of 26 schizophrenics and 23 controls measured with a volume-selective P-MRS method were investigated. Overall, we could not find any correlations between WCST results and phospholipid levels, but in controls phosphocreatine% (PCr%) and PCr/adenenosine triphosphate (ATP) ratios were negatively correlated with test performance. Since PCr behaves as a buffer of ATP, in the sense that when ATP is consumed by neuronal activity PCr is catalysed rapidly to ATP, increased PCr% values and, moreover, increased PCr/ATP ratios point to a decreased ATP consumption. Thus, the correlations found between PCr% and PCr/ATP and test performance in controls point to an association between reduced performance in a specific frontal lobe task and decreased energy demanding processes at rest. This association was not found in schizophrenics, possibly due to the influence of neuroleptic medication or the disease process per se.

Adenosine Triphosphate↗
PubMed1998

Classification of human scleral spur cells in monolayer culture.

Aqueous humor outflow in primate eyes can be facilitated by ciliary muscle contraction, thereby widening fluid pathways through the trabecular meshwork. Recently in the scleral spur smooth muscle (sm) alpha-actin positive myofibroblast-like cells have been described which are in contact with the elastic fiber system of both the spur and trabecular meshwork. In the vicinity of these cells nerve terminals have been described. It is speculated that contraction of scleral spur cells can facilitate aqueous humor outflow, too. To provide a tool for further physiological and pharmacological studies monolayer cell cultures of human scleral spur have been established and characterized. For this purpose, cells derived from scleral spur, outer and inner trabecular meshwork and ciliary muscle tips from 7 donor eyes (43-87 years-old respectively, obtained 3-7 h post mortem) were grown in tissue culture medium and the different monolayer cells classified by their growth characteristics, and by immunohistochemical staining for vimentin, alpha-sm-actin, desmin, and alpha B-crystallin, respectively. In addition, the presence of alpha B-crystallin mRNA and desmin mRNA was verified using the polymerase chain reaction (PCR)-method. We were able to characterize and distinguish human scleral spur cells from adjacent ciliary muscle and trabecular meshwork cells. Scleral spur cells (SPC) grew slower than ciliary muscle cells (CMC) but much faster than trabecular meshwork cells (TMC). All cells showed the same staining characteristics in vitro as they did in vivo. Scleral spur cells stained for vimentin and alpha-sm-actin, but not for desmin and alpha B-crystallin. The corresponding mRNAs of the latter two proteins could not be detected by PCR in the spur cells. Cells grew out from all donor eyes so that they actually provide a tool for further experimental studies.

Cell Culture Techniques↗
PubMed1998

[Reliability and validity studies with the triflexometer, a new method for assessing form and flexibility of the spine].

Developed by Orthotronic Medizintechnik GmbH, the so-called Triflexometer, version 3.22 was tested for its reliability and validity in measuring spinal posture and mobility. Reliability studies on 20 healthy subjects have shown this measurement method to be reliable, yet intra- and inter-rater reliability analyses also revealed that even for this healthy population discrepancies in the various measures may occur, both due to differences in compliance as well as fatigue and learning effects, and due to difficulties in stabilization of the normal posture, to a lesser extent due to certain specifics of the measurement technique (placing the markers, guiding the sensor). In total spinal immobility (ankylosing spondylitis), practically identical measurements are found, as is the case in dummy studies. The validity study on 20 healthy subjects found good correlations between the measurements obtaining using the triflexometer and those for double inclinometer, respectively, and that only minor mean value differences occur for the two methods. Also, triflexometer measurements for total anteflexion were found to correlate with those determined with the fingertip-to-floor method, no correlation was present however between the Triflexometer values and the Schober test. Triflexometer measurements performed on 114 healthy subjects of various ages served to prove that the range of spinal movement in the directions measured (sagittal and frontal) will reduce with age. To a lesser extent, this also applies to hip movement. Overall, our findings prove the triflexometer an easy-to-handle system which possesses high reliability and is suitable for valid and objective noninvasive assessment of global and segmental spinal mobility. Triflexometer examinations are highly uncomplicated to implement, and print-outs of the results obtained permit lasting documentation of the present status.

Adult↗
PubMed1997

Jun NH2-terminal kinase is constitutively activated in T cells transformed by the intracellular parasite Theileria parva.

When T cells become infected by the parasite Theileria parva, they acquire a transformed phenotype and no longer require antigen-specific stimulation or exogenous growth factors. This is accompanied by constitutive interleukin 2 (IL-2) and IL-2 receptor expression. Transformation can be reversed entirely by elimination of the parasites using the specific drug BW720c. Extracellular signal-regulated kinase and jun NH2-terminal kinase (JNK) are members of the mitogen-activated protein kinase family, which play a central role in the regulation of cellular differentiation and proliferation and also participate in the regulation of IL-2 and IL-2 receptor gene expression. T. parva was found to induce an unorthodox pattern of mitogen-activated protein kinase expression in infected T cells. JNK-1 and JNK-2 are constitutively active in a parasite-dependent manner, but have altered properties. In contrast, extracellular signal-regulated kinase-2 is not activated even though its activation pathway is functionally intact. Different components of the T cell receptor (TCR)-dependent signal transduction pathways also were examined. The TCRzeta or CD3epsilon chains were found not to be phosphorylated and T. parva-transformed T cells were resistant to inhibitors that block the early steps of T cell activation. Compounds that inhibit the progression of T cells to proliferation, however, were inhibitory. Our data provide the first example, to our knowledge, for parasite-mediated JNK activation, and our findings strongly suggest that T. parva not only lifts the requirement for antigenic stimulation but also entirely bypasses early TCR-dependent signal transduction pathways to induce continuous proliferation.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

Carbonic anhydrase activity is increased in retinal pigmented epithelium and choriocapillaris of RCS rats.

BACKGROUND: In Royal College of Surgeons (RCS) rats the retinal pigmented epithelium (RPE) exhibits defective phagocytosis of rod outer segments, causing degeneration of the photoreceptor layer. It is not known whether another function of the RPE, ion and fluid transport, is also affected by the disease. One enzyme involved in modulation of RPE transport activities is carbonic anhydrase (CA). To clarify whether changes in CA activity are correlated with the process of retinal degeneration, the localization of CA activity in RCS rat eyes was investigated. METHODS: Eyes of 12 RCS rats and 12 age-matched congenic controls of different ages were studied, using a modified histochemical method of Hansson for light and electron microscopy. RESULTS: Control eyes showed CA staining in corneal endothelium, both layers of ciliary epithelium, Müller cells, inner segments of photoreceptors, and RPE cells. In RPE the apical membranes were most intensely stained. In RCS rats, changes in CA staining were seen only in the posterior segment of rats 6 and 7 months of age. Most of the RPE cells were more intensely stained than those of age-matched controls, especially due to increased CA activity in the basolateral membrane infoldings. Adjacent endothelial cells of the choriocapillaris and of retinal capillaries developed staining for CA activity. CONCLUSION: Changes in CA activity in the RPE and adjacent capillary endothelium, together with previously described changes in RPE morphology in RCS rats, indicate changes in ion and fluid transport across the RPE. Since the retina was already impaired when the increase in CA activity occurred, we hypothesize that the causative factor is not the genetic defect per se, but the destruction of the retina.

Animals↗
PubMed1995

Partial inhibition of Theileria parva-infected T-cell proliferation by antisense IL2R alpha-chain RNA expression.

Antisense RNA expression was used to assess the role of the interleukin 2 receptor (IL2R) alpha-chain in proliferation of T cells transformed by infection with the intracellular parasite Theileria parva. Two vectors were constructed, in which part of the bovine IL2R alpha-chain cDNA was inserted in either a sense or antisense orientation in the plasmid pHS1-CAT, which is expressed by induction of the human metallothionein IIA (hMT-IIA) with cadmium (Cd2+). A T. parva-infected T-cell line, TpM(803), known to express the IL2 and IL2R genes in a constitutive way, was permanently transfected with one of the two constructs, and the effect of antisense IL2R alpha-chain RNA expression upon proliferation of TpM(803) cells was tested. Antisense-transfected TpM(803) cells grew much more slowly than sense-transfected cells even in the absence of added Cd2+, but the addition of Cd2+ to the culture medium resulted in further inhibition. A strong reduction in IL2R alpha-chain mRNA was observed in antisense but not in sense-transfected cells. These observations confirm a role for the IL2R alpha-chain in proliferation of T. parva-infected TpM(803) cells.

Animals↗
PubMed1994

Altered proportions of RCS-rat eyes.

The growth pattern of RCS-rat eyes with hereditary retinal degeneration was analysed morphometrically, evaluating midsagittal sections of the entire globe and sections of the chamber angle region. No changes of the axial diameter of RCS-rat eyes were found if compared with eyes of age-matched controls. There were, however, characteristic proportional changes in the anterior eye segment of RCS rats. The distance between the peripheral end of Descemet's membrane (DM) and both the posterior end of Schlemm's canal and the ora serrata were significantly elongated indicating that this region might be most susceptible to growth factors. The length of the posterior globe up to the level of the ora serrata was shorter in RCS rats than in control rats. In addition, in RCS-rat eyes the pars plana was significantly elongated and the pars plicata shortened. Ultrastructural changes of ciliary epithelium were not seen before 7 months of age in RCS rats. They were only present in those parts of the circumference in which the stromal capillaries also revealed structural changes. The ciliary epithelial alterations were therefore considered secondary to narrowing or rarefication in the adjacent blood vessels.

Animals↗