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Biomedical subjects

M Heine

Publications and source records attributed to M Heine.

At least 19 recordsLinked to original sources
PubMed2003

Carboxyfluorescein diacetate succinimidyl ester facilitates cell tracing and colocalization studies in bioartificial organ engineering.

BACKGROUND: We demonstrate a method that includes colocalization studies to analyze cell suspensions after isolation and to characterize 3-dimensional grafts consisting of cells and matrix in vitro and in vivo. MATERIALS AND METHODS: Neonatal rat cardiomyocytes were labelled by CFDA-SE after harvest. Cells in the isolated cell suspension, the embodied cells in the seeded scaffolds were characterized measuring features such as viability and distribution of the cell types. RESULTS: Selective cell count revealed high yields of viable cardiomyocytes. After seeding cells in collagen matrix, viability of the cells decreased gradually in the time process in vitro. Histology of implanted bioartificial myocardial tissue detected viable cardiomyocytes within the graft. CONCLUSION: Using colocalization histology we could label and track cells within the bioartificial myocardial tissue graft in vitro and post implant and assess viability and distribution.

Animals↗
PubMed2001

5-Hydroxytryptamine 4(a) receptor expressed in Sf9 cells is palmitoylated in an agonist-dependent manner.

The mouse 5-hydroxytryptamine 4(a) receptor [5-HT(4(a))] was expressed with a baculovirus system in insect cells and analysed for acylation. [(3)H]Palmitic acid was effectively incorporated into 5-HT(4(a)) and label was sensitive to the treatment with reducing agents indicating a thioester-type bond. Analysis of protein-bound fatty acids revealed that 5-HT(4(a)) contains predominantly palmitic acid. Treatment of infected Sf9 (Spodoptera frugiperda) cells with BIMU8 [(endo-N-8-methyl-8-azabicyclo[3.2.1]oct-3-yl)-2,3-dehydro-2-oxo-3-(prop-2-yl)-1H-benzimid-azole-1-carboxamide], a 5-HT(4) receptor-selective agonist, generated a dose-dependent increase in [(3)H]palmitate incorporation into 5-HT(4(a)) with an EC(50) of approx. 10 nM. The change in receptor labelling after stimulation with agonist was receptor-specific and did not result from general metabolic effects. We also used both pulse labelling and pulse-chase labelling to address the dynamics of 5-HT(4(a)) palmitoylation. Incorporation studies revealed that the rate of palmitate incorporation was increased approx. 3-fold after stimulation with agonist. Results of pulse-chase experiments show that activation with BIMU8 promoted the release of radiolabel from 5-HT(4(a)), thereby reducing the levels of receptor-bound palmitate to approximately one-half. Taken together, our results demonstrate that palmitoylation of 5-HT(4(a)) is a reversible process and that stimulation of 5-HT(4(a)) with agonist increases the turnover rate for receptor-bound palmitate. This provides evidence for a regulated cycling of receptor-bound palmitate and suggests a functional role for palmitoylation/depalmitoylation in 5-hydroxytryptamine-mediated signalling.

Amino Acid Sequence↗
PubMed2001

[Rhinosporidiosis. A rare cause of nosebleed].

Due to an increasing number of non-European patients and tourists travelling in endemic aras, "exotic" mycosis and other tropical diseases must be considered in differential diagnosis. In this report we present a patient with epistaxis caused by rhinosporidiosis, an endemic disease in South India and Sri Lanka (Ceylon) and quite rare in Europe. This chronic inflammatory disease characterized by hyperplastic polypoid lesions of the mucous membrane, predominantly nasal, is caused by Rhinosporidium seeberi, a parasite with a complicated life cycle and an uncertain taxonomy. The commonest and often the presenting symptom is epistaxis. The treatment of choice is surgery with risks of recurrence.

Adult↗
PubMed2001

[Reducing the duration of pattern ERG recordings by "time varying filtering"].

PROBLEM: In 1981, de Weerd proposed the method of time varying filtering (TVF) for estimating the "true" signal of an electrophysiological response if a noise response was additionally recorded. We studied whether this method can be used to predict the average pattern ERG (PERG) of all trials from a smaller subset of trials. METHODS: A total of 10 subjects with normal acuity participated in the experiment. Transient PERGs to reversing checkerboard patterns were recorded from both eyes using DTL electrodes. We calculated the mean deviation for partial averages of 6, 12, 20, 30, and 60 trials from the average PERG of all 120 trials. For each partial average, an additional noise response was derived by averaging the trials with alternating signs. RESULTS: When using TVF, the number of trials could be reduced by a factor of 1.43 to yield a PERG of similar quality to classical averaging. CONCLUSION: TVF allows the estimation of a "true" PERG response. This method can be used to significantly reduce the duration of PERG recordings.

Adult↗
PubMed2001

Calcium-induced calcium release in neurosecretory insect neurons: fast and slow responses.

The dynamics of intracellular free Ca(2+)([Ca(2+)](i)) changes were investigated in dorsal unpaired median (DUM) neurons of the cockroach Periplaneta americana. Activation of voltage-gated Ca(2+) channels caused a steep increase in [Ca(2+)](i). Depolarizations lasting for < 100ms led to Ca(2+) release from intracellular stores as is indicated by the finding that the rise of [Ca(2+)](i) was greatly reduced by the antagonists of ryanodine receptors, ryanodine and ruthenium red. There is a resting Ca(2+)current which is potentiated on application of a neuropeptide, Neurohormone D (NHD), a member of the adipokinetic hormone family. Ca(2+) influx enhanced in this way again caused a rise of [Ca(2+)](i) sensitive to ryanodine and ruthenium red. Such rises developed and relaxed much more slowly than the depolarization-induced signals. Ca(2+)responses similar to those induced by NHD were obtained with the ryanodine receptor agonists caffeine (20mM) and cADP-ribose (cADPR, 100nM). These Ca(2+) responses, however, varied considerably in size and kinetics, and part of the cells did not respond at all to caffeine or cADPR. Such cells, however, produced Ca(2+) rises after having been treated with NHD. Thus, the variability of Ca(2+) signals might be caused by different filling states of Ca(2+) stores, and the resting Ca(2+) current seems to represent a source to fill empty Ca(2+) stores. In line with this notion, block of the endoplasmic Ca(2+) pump by thapsigargin (1 microM) produced either no or largely varying Ca(2+) responses. The Ca(2+) signals induced by caffeine and cADPR displayed different sensitivity to ryanodine receptor blockers. cADPR failed to elicit any response when ryanodine or ruthenium red were present. By contrast, the response to caffeine, in the presence of ryanodine, was only reduced by about 50% and, in the presence of ruthenium red, it was not at all reduced. Thus, there may be different types of Ca(2+) release channels. Block of mitochondrial Ca(2+) uptake with carbonyl cyanide m -chlorophenylhydrazone (CCCP, 1 microM) completely abolished cADPR-induced Ca(2+) signals, but it did not affect the caffeine-induced signals. Taken together our findings seem to indicate that there are different stores using different Ca(2+) uptake pathways and that some of these pathways involve mitochondria.

Adenosine Diphosphate Ribose↗
PubMed2000

Evaluation of DNA ploidy and degree of DNA abnormality in benign and malignant melanocytic lesions of the skin using video imaging.

BACKGROUND: Making a morphologic distinction between benign and malignant melanocytic tumors of the skin is frequently difficult, especially because "gray zones" between these lesions often exist. DNA image cytometry as an adjuvant method for the diagnosis and prognostic prediction of premalignant lesions and malignant tumors of many other organs is already well established. The aim of this study was to determine whether DNA image cytometry is helpful in distinguishing benign from malignant melanocytic lesions and whether cytometry would give valid information with which to predict the prognoses associated with malignant melanomas. METHODS: DNA image cytometry was performed on 127 benign and 58 primary maligant melanomas of the skin as well as 11 metastatic melanomas, using an enzymatic single cell solution according to a method described by Heiden et al. in Cytometry (1991;12:614-21). RESULTS: DNA aneuploidy was graded by DNA index (DI) and a 2c deviation index (2cDI). In contrast to benign melanocytic lesions (with 16% DNA aneuploidy), primary and metastatic malignant melanomas had significantly higher frequencies of DNA aneuploidy (86% and 73%, respectively). In the degree of DNA aneuploidy, significant differences between benign and malignant melanocytic tumors could be observed. The mean 2cDI of aneuploid benign lesions was 1.0, whereas the primary malignant melanomas had a mean 2cDI of 2.92 and the metastatic melanomas a mean of 6.9. The frequency of DNA aneuploidy increased with Breslow thickness. Twenty-one patients with primary malignant melanoma developed metastases. All metastasizing primary tumors were aneuploid and showed a significantly higher grade of DNA aneuploidy than nonmetastasizing malignant melanomas. Moreover, none of the diploid malignant melanomas developed metastases. CONCLUSIONS: This study reveals that DNA image cytometry is prognostically and diagnostically relevant to the evaluation of melanocytic lesions of the skin. Nevertheless, it cannot be relied on alone to provide enough information for a diagnosis.

Adult↗
PubMed1998

Ca2+ resting current and Ca2+-induced Ca2+ release in insect neurosecretory neurons.

The effect of a Ca2+ resting current on spiking and intracellular Ca2+ concentration [Ca2+]i of isolated cockroach dorsal unpaired median neurons was investigated by combining microfluometry (Fura2) with patchclamping. The resting current was reduced by 10 microM 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and 10 microM mefenamic acid, which caused slower spiking of cells. Up-modulation of the resting current by neurohormone D (NHD, 100 fM to 10 pM) transiently increased [Ca2+]i. This Ca2+ transient was largely reduced by the ryanodine receptor antagonist dantrolene (10 microM) but it was not reduced by the IP3-receptor antagonist heparin which indicates Ca2+-induced Ca2+ release. The NHD-effect on [Ca2+]i was strongly attenuated by NPPB and mefenamic acid. Thus, NHD caused Ca2+-induced Ca2+ release by enhancing the Ca2+ resting current.

Action Potentials↗
PubMed1998

Entry into afferent lymphatics and maturation in situ of migrating murine cutaneous dendritic cells.

An important property of dendritic cells (DC), which contributes crucially to their strong immunogenic function, is their capacity to migrate from sites of antigen capture to the draining lymphoid organs. Here we studied in detail the migratory pathway and the differentiation of DC during migration in a skin organ culture model and, for comparison, in the conventional contact hypersensitivity system. We report several observations on the capacity of cutaneous DC to migrate in mouse ear skin. (i) Upon application of contact allergens in vivo the density of Langerhans cells in epidermal sheets decreased, as determined by immunostaining for major histocompatibility complex class II, ADPase, F4/80, CD11b, CD32, NLDC-145/DEC-205, and the cytoskeleton protein vimentin. Evaluation was performed by computer assisted morphometry. (ii) Chemically related nonsensitizing or tolerizing compounds left the density of Langerhans cells unchanged. (iii) Immunohistochemical double-staining of dermal sheets from skin organ cultures for major histocompatibility complex class II and CD54 excluded blood vessels as a cutaneous pathway of DC migration. (iv) Electron microscopy of organ cultures revealed dermal accumulations of DC (including Birbeck granule containing Langerhans cells) within typical lymphatic vessels. (v) Populations of migrating DC in organ cultures upregulated markers of maturity (the antigen recognized by monoclonal antibody 2A1, CD86), but retained indicators of immaturity (invariant chain, residual antigen processing function). These data provide additional evidence that during both the induction of contact hypersensitivity and in skin organ culture, Langerhans cells physically leave the epidermis. Both Langerhans cells and dermal DC enter lymphatic vessels. DC mature while they migrate through the skin.

Animals↗
PubMed1998

[Screening for amblyopia, strabismus and refractive abnormalities in 1,030 kindergarten children].

BACKGROUND: There are controversies concerning the necessity of pre-school vision screening. AIM OF THE STUDY: evaluation of the prevalence of pathologic ophthalmologic findings in kindergarten children. MATERIALS AND METHODS: 1030 families were offered a vision screening. Of these, a total of 948 children, aged 3 to 6 years, voluntarily underwent a screening for strabismus, amblyopia and refractive anomalies. The examination was performed in the kindergarten in the absence of the parents. METHODS OF EXAMINATION: A questionnaire concerning general and ophthalmologic history of the child and of the family was evaluated. Visual acuity, cover-uncover-test, Lang-stereotest, retinoscopy, ophthalmoscopy (undilated pupils) were performed and the glasses were evaluated. RESULTS: The screening was highly accepted by the parents and 92% of the families (n = 948) took part. The compliance of the children was very good. A total of 38.7% (n = 381) of the children showed one or more abnormal parameters. 21.4% (n = 229) showed a reduced visual acuity. Strabismus was found in 3.7%. Half of the children with abnormal findings already had had a vision screening, but only 25% had received ophthalmologic treatment. Of those who possessed glasses, 25% came without them, and another 25% had a reduced visual acuity even with their glasses. The main problems were many false-positive results and high costs. CONCLUSIONS: Ophthalmologic and orthoptic screening in kindergarten is technically easy and conclusive in experienced hands. Ideas to reduce costs and to avoid overreferrals are an age-related lowering of the visual acuity limit and a rescreening of suspected children in a screening-setting a second time before sending them to an ophthalmologist. Another possibility to reduce costs would be to perform examinations not by ophthalmologists but by "screening-orthoptists" who should be trained in retinoscopy and ophthalmoscopy.

Amblyopia↗
PubMed1998

Evaluation and validation of a Crohn's disease inflammatory activity index reflecting pattern of endoscopic severity.

BACKGROUND: This study was designed to investigate objective variables assessing the inflammatory activity of Crohn's disease accessible for routine management and their suitability to act as surrogate indicators for endoscopic alterations. METHODS: Thirty-six patients were included in a prospective study and underwent endoscopic investigation, 18 with clinically exacerbated disease and 18 after acute-phase conservative therapy. The endoscopic findings were classified to define the dependent variable, yielding two categoric levels: acute active disease and remission. The extent of affected mucosal area was not taken into consideration. The serum variables alpha1-antitrypsin, acid alpha1-glycoprotein (AGP), C-reactive protein (CRP), sialic acids, prealbumin (PAB), and albumin were used as independent variables to predict the dependent variable. To compare the results with common indices, the Crohn's Disease Activity Index (CDAI) and van Hees Index were calculated. RESULTS: The following model was calculated by stepwise logistic regression analysis: if AGP (mg/dl) -4.2 x PAB (mg/dl) > or =0.8, then endoscopically active disease will be predicted with a sensitivity of 100% and a specificity of 95% (P < 0.001). The predictive values of the single variables, CDAI, and van Hees Index were lower. For validation of results an analogous study was performed including 44 patients, 29 with active disease and 15 controls. The existence of the model was confirmed, again showing high values for sensitivity (86%) and specificity (100%). CONCLUSIONS: On a qualitative level focusing on clinical relevance, the endoscopic and biologic findings of Crohn's disease are highly associated. In addition to clinical assessment, usage of the developed index as a rationale contributing to therapeutic decisions in the short- and long-term management might be reasonable.

Biomarkers↗
PubMed1998

Effects of partial liquid ventilation on lung injury in a model of acute respiratory failure: a histologic and morphometric analysis.

OBJECTIVE: To compare the histopathologic changes observed in a sheep model of oleic acid-induced acute respiratory failure during partial liquid ventilation with perflubron with gas ventilation. DESIGN: Randomized, controlled study. SETTING: Animal laboratory and pathology laboratories of a university hospital. SUBJECTS: Fourteen healthy adult sheep, weighing 64.9 +/- 6.4 kg. INTERVENTIONS: Lung injury was induced with oleic acid (0.15 mL/kg). A tracheostomy tube was inserted, along with systemic and pulmonary artery monitoring catheters. Animals were randomized to undergo either partial liquid ventilation (n = 7) or gas ventilation (n = 7). Animals underwent euthanasia at the end of the 90-min study period, after which the endotracheal tube was clamped with the lungs in expiratory hold at a positive end-expiratory pressure of 5 cm H2O. En bloc excision of the heart and lungs was performed by thoracotomy. Perfusion of the isolated lung vasculature with 2.5% paraformaldehyde and 0.25% glutaraldehyde in a 0.1-M phosphate buffer was performed. Histologic analysis followed. MEASUREMENTS AND MAIN RESULTS: Gas exchange increased markedly in the animals that underwent partial liquid ventilation compared with the gas-ventilated animals (PaO2 at 90 mins: gas ventilation-treatment group, 40 +/- 8 torr [5.3 +/- 1.1 kPa]; partial liquid ventilation-treatment group, 108 +/- 60 torr [14.4 +/- 8.0 kPa]; p = .004). Lung histologic analysis demonstrated a better overall diffuse alveolar damage score (partial liquid ventilation-treatment group, 12.4 +/- 1.4; gas ventilation-treatment group, 15.0 +/- 1.7; p = .01). In the partial liquid ventilation-treatment group, we observed an increase in mean alveolar diameter (partial liquid ventilation-treatment group, 82.4 +/- 2.9 microm; gas ventilation-treatment group, 67.7 x 3.9 microm; p = .0022) and a decrease in the number of alveoli per high-power field (partial liquid ventilation-treatment group, 25.7 +/- 0.9, gas ventilation-treatment group, 31.4 +/- 2.5; p = .0022), in septal wall thickness (partial liquid ventilation-treatment group, 6.0 +/- 0.6 microm; gas ventilation-treatment group, 8.3 +/- 1.0 microm; p = .0033), and in mean capillary diameter (partial liquid ventilation-treatment group, 13.0 +/- 0.8 microm; gas ventilation-treatment group, 19.9 +/- 1.4 microm; p = .0022). CONCLUSIONS: Partial liquid ventilation is associated with notable improvement in gas exchange and with a reduction in the histologic and morphologic changes observed in an oleic acid model of acute lung injury.

Animals↗
PubMed1996

An improved isolation method for murine migratory cutaneous dendritic cells.

Dendritic cells are highly specialized accessory cells for the initiation of primary immune responses. They occur as trace populations in non-lymphoid and lymphoid organs. Therefore, the isolation and enrichment of primary dendritic cells is difficult and time-consuming. This applies also to dendritic cells from skin, i.e. epidermal Langerhans cells and dermal dendritic cells. Recently introduced skin organ cultures serve as a convenient source for primary cutaneous dendritic cells. We report here a refinement of such cultures in which cutaneous dendritic cells emigrate spontaneously into the culture medium. Murine ear skin is cultured for a total of 3 days in three sequential 24 h steps. This simple modification doubles or triples the yields of dendritic cells that can be obtained and up to 30,000 dendritic cells can be recovered from one ear half. This represents 50-70% (range 30-80%) of all viable cells. The cells are mature dendritic cells that possess potent T cell stimulatory function. Compared to the classical methods of preparing epidermal Langerhans cells by trypsinization this technique is easier and quicker; it does not require enzymes such as trypsin, and it yields similar numbers of mature dendritic cells. It should prove useful for further studies of dendritic cells of the skin.

Animals↗
PubMed1996

Ligand-dependent interaction of nuclear receptors with potential transcriptional intermediary factors (mediators).

The activity of the ligand-inducible activation function 2 (AF-2) contained in the ligand binding domain (LBD) of nuclear receptors (NRs) is thought to be mediated by transcriptional intermediary factors (TIFs). We have recently reported the isolation and characterization of two novel mouse proteins, designated TIF1 and mSUG1, that interact in a ligand-dependent fashion with the LBD (region E) of several NRs in vivo as well as in vitro. Remarkably, these interactions require the conserved core motif of the AF-2 activating domain (AF-2 AD) and can be blocked by AF-2 antagonists. TIF1 and mSUG1 might therefore represent TIFs/mediators for the ligand-dependent AF-2 of NRs. By comparing the interaction properties of these two putative TIFs with different NRs including the oestrogen (ER), thyroid hormone (TR), vitamin D3 (VDR), retinoic acid (RAR alpha) and retinoid X (RXR) receptors, we demonstrate that: (i) RXR alpha efficiently interacts with TIF1, but not with mSUG1, whereas TR alpha interacts much more efficiently with mSUG1 than with TIF1, and RAR alpha, VDR and ER efficiently interact with both TIF1 and mSUG1; (ii) the amphipathic alpha helix core of AF-2 AD is differentially involved in the interactions of RAR alpha with TIF1 and mSUG1; and (iii) the AF-2 AD cores of RAR alpha and ER are similarly involved in their interaction with TIF1, but not with mSUG1. Thus the interaction interfaces between the various NRs and either TIF1 or mSUG1 may vary depending on the nature of both the receptor and the putative mediator of its AF-2 function. We discuss the possible roles of TIF1 and mSUG1 as mediators of the transcriptional activity of the AF-2 of NRs.

Animals↗
PubMed1996

Diaphragmatic paralysis following scalenotomy for thoracic outlet syndrome.

Potential phrenic nerve injury that results in diaphragmatic dysfunction and respiratory insufficiency has important implications for the anesthesiologist who must insure adequate ventilation and gas exchange. A variety of traumatic injuries as well as some surgical manipulations have been identified with an increased frequency of diaphragmatic paralysis. We have observed the occurrence of this sequelae after scalenotomy for thoracic outlet obstruction, a previously unreported association.

Diagnosis, Differential↗
PubMed1995

Mutation and expression of TP53 in malignant melanomas.

Mutations of the TP53 gene are the most common genetic alterations in human malignancies. Overexpression of the p53 protein has been reported in high frequencies in all types of skin cancer. To determine the role of TP53 in the pathogenesis of malignant melanoma, we investigated the expression of p53 in 12 cell lines and 145 primary and metastatic lesions by immunohistochemistry. Overexpression of p53 was predominantly detected in the cytoplasm of the cells in 96 (66%) tumor and 12 (93%) cell lines. In contrast to findings in other tumor types, in melanomas immunoreactive cells were found in clusters or as scattered single cells. In primary melanomas, the frequency of p53 overexpression did not correlate with tumor thickness. Nucleotide sequencing of TP53 genes of 24 melanoma tumors/cell lines demonstrated point mutations in seven samples, all coding for mutant p53 protein species. The frequency of TP53 alterations of 20%-30% is lower than in other skin tumor types. Notably, immunohistochemistry was not a suitable method to distinguish overexpression of wild-type p53 from mutant species, since cell lines/tumors with TP53 mutations did not show distinctive staining patterns. The mutation pattern in six out of seven lesions was similar to that caused by ultraviolet light damage. This finding may be regarded a further indication for a pathogenetic role of UV light damage in at least a subgroup of malignant melanomas.

Antibodies, Monoclonal↗