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Biomedical subjects

M Hartmann

Publications and source records attributed to M Hartmann.

At least 145 records · Page 8Linked to original sources
PubMed1997

Early experience with intravenous immunoglobulin treatment in Wegener's granulomatosis with ocular involvement.

BACKGROUND: Pooled intravenous gammaglobulin (IVIg) was reported to be effective in the treatment of Wegener's granulomatosis (WG). No reports have been made on the effects of this new treatment on ocular manifestations of WG. METHOD: IVIg treatment was given to two patients suffering from WG with ocular involvement after several other treatment regimes had failed. RESULTS: Although the systemic disease was under control, the ocular symptoms of both patients worsened during and after IVIg treatment. In one case an adverse effect consisting of retinal vasculitis was noted on two occasions. CONCLUSION: Although beneficial effects of IVIg treatment on WG have been previously described, the two cases with ocular involvement presented here did not reveal any positive response. Paradoxical and unpredictable reactions cannot be ruled out. Thus, patients treated with IVIg should be closely surveyed by an ophthalmologist.

Adult↗
PubMed1997

[Primary malignant lymphoma of the brain].

Primary malignant lymphoma of the brain is a disease of unknown etiology, which is increasing in incidence and has an unfavorable prognosis. Despite the lack of specific changes on CT or MRI in most cases, these procedures may typically facilitate the diagnosis: a focal-enhancing mass with subependymal spread on CT or MRI and hyperattenuation on nonenhanced CT are the most reliable features in the diagnosis of primary malignant lymphoma of the brain. Peritumoral edema and mass effect are usually not prominent features. On unenhanced CT scans they usually appear homogeneously isodense to mildly hyperdense relative to the gray matter. On MRI these tumors are slightly hypointense on T1-weighted images and slightly hyperintense on PD- and T2-weighted images relative to the gray matter. On CT and MRI enhancement is usually homogeneous. Contrast-enhanced MRI, with its multiplanar capability, lack of bone-induced artifacts, and high-contrast resolution, is likely to reveal subependymal spread and meningeal involvement that have escaped detection by CT. Because there are no specific features on CT or MRI in most cases, patients who are suspected of having primary malignant lymphoma of the brain should immediately undergo biopsy and, if the diagnosis is confirmed, whole-brain radiation therapy. With early diagnosis and treatment, these patients benefit from radiation therapy.

Brain↗
PubMed1997

Cytokeratin 17 as an immunohistochemical marker for intramural cytotrophoblast in human first trimester uteroplacental arteries.

Trophoblast cells, as blastocyst-wall derivatives, are of epithelial origin and differentiate initially into syncytiotrophoblast and cytotrophoblast subpopulations. Cyto- and syncytiotrophoblasts are the two cell types present in the surface cell layers of placental villi. Cytotrophoblastic cells lie in contact with the basal lamina and are the proliferating stem cells that guarantee cytotrophoblast and syncytiotrophoblast persistence. Implantation and placenta formation are mainly based on these two cell types. Villous cytotrophoblasts are the stem cells for all extravillous trophoblast subpopulations, which exhibit strictly regulated invasiveness. One aspect of extravillous trophoblasts is that they invade maternal endometrial spiral arteries and dilate them in order to achieve sufficient fetal blood supply. During this process, trophoblast cells, which are located in the remodelled uteroplacental artery walls, are thus defined as intramural cytotrophoblasts. Trophoblast differentiation is accompanied and defined by alterations in, for example, the translation pattern for cytokeratin genes. In an immunohistochemical study, we have demonstrated that only intramural cytotrophoblasts, from all the trophoblast populations of the junctional zone, express cytokeratin 17. Furthermore, cell shape and vascular architecture indicate that, in human placenta, intra-arterial trophoblast cells reach their destination by migration through the endometrial interstitium with consecutive intravasation. Cytokeratin 17, in particular, can therefore be used as a specific immunohistochemical marker for the intramural trophoblast subpopulation.

Arteries↗
PubMed1997

Immunohistochemical examination of trophoblast populations in human first trimester and term placentae and of first trimester spiral arteries with the monoclonal antibody GZ 112.

This paper presents an immunohistochemical study with a monoclonal mouse antibody GZ 112, an IgG1 kappa, which is directed against an antigen expressed in first trimester placenta by all proliferative and invasive extravillous trophoblast populations including a population of Langhans cells that represent extravillous stem cells. Additionally, the GZ 112 antigen is associated with morphological changes of spiral arteries preceding local trophoblast invasion. In term placentae, GZ 112 also strongly reacts with all extravillous trophoblast populations, but additionally recognizes partly villous cytotrophoblast and syncytiotrophoblast too, displaying a heterogeneous staining pattern. GZ 112 is directed against a 42-KDa antigen. Intracytoplasmic network-like staining and cross-reactivity with various human surface and glandular epithelia indicate a cytokeratin intermediate filament or a cytokeratin intermediate filament associated molecule as antigen.

Animals↗
PubMed1997

Alterations of the metastasis suppressor gene nm23 and the proto-oncogene c-myc in human testicular germ cell tumors.

The putative metastasis suppressor genes nm23-H1, nm23-H2 and the c-myc proto-oncogene were investigated in testicular germ cell tumors (GCTs) using Southern and Northern blotting as well as semiquantitative reverse transcription polymerase chain reaction (RT-PCR) and single strand conformation polymorphism (SSCP) analysis. When studying Bgl II RFLPs, allelic losses of the nm23 gene were found in 3/12 (25%) informative tumors, and all 3 had lymph node and/or distant metastases. A 2 to 7 fold nm23 mRNA overexpression was found in 22/34 (64.7%) tumors examined. RT-PCR revealed that this phenomenon is mainly a consequence of nm23-H2 overexpression. Overexpression of both the H1 and the H2 gene was predominantly found in the seminoma subtype and was not associated with tumor stage. Only 1/25 tumors, a seminoma with distant metastases, had a point mutation in the coding region of the nm23-H2 gene as demonstrated by SSCP analysis. None of the 8 seminomas and only 1/13 non-seminomas had c-myc overexpression. No abnormalities of the c-myc gene could be detected on the DNA level. Despite the fact that in previous investigations nm23-H2 was demonstrated to be a putative transcription factor for c-myc, no coexpression of c-myc and nm23-H2 was found by quantitative RT-PCR in this study.

Chromosome Aberrations↗
PubMed1997

Amnion epithelial cells, in contrast to trophoblast cells, express all classical HLA class I molecules together with HLA-G.

PROBLEM: The expression of the non-classical HLA-G gene has been shown at the protein level on trophoblast-derived embryonic tissue, like the extravillous cytotrophoblast. However, the presence of HLA-G on embryoblast-derived cells is currently controversial. The amnion epithelium is an embryoblast-derived cell layer covering the amnion cavity and is the main source for the amnion fluid. METHOD: The expression of HLA class I molecules was investigated by immunohistochemical, biochemical, and molecular biological methods in amnion membranes and amnion fluid. RESULTS: Immunohistochemically, HLA-C and occasionally also-B molecules as well as HLA-A and/or -G molecules have been identified on amnion epithelial cells. These results were extended by Western blotting with purified amnion epithelial cells where HLA-B and/or -C, HLA-A and HLA-G antigens have been detected. As expected HLA-G mRNA was detected in amino epithelial cells. Furthermore, classical HLA molecules as well as HLA-G were found in amnion fluid. CONCLUSION: These results show that the amnion epithelium frequently expresses classical HLA class I molecules as well as HLA-G. The expression of HLA-G antigens on amnion epithelial cells and their presence in the amnion fluid, which is continually ingested by the fetus, may be particularly relevant for the induction of peripheral tolerance.

Amnion↗
PubMed1997

Immunohistochemical pattern of insulin-like growth factor (IGF) I, IGF II and IGF binding proteins 1 to 6 in carcinoma in situ of the testis.

AIM: To study the immunohistochemical localisation of insulin-like growth factor (IGF) I, IGF II, and IGF binding proteins 1-6 in intratubular germ cell neoplasia in the vicinity of solid germ cell tumours of the testis. METHODS: Testes were obtained from 13 patients (20-35 years old) who had undergone orchidectomy for treatment of a solid germ cell tumour. Tumour cells were verified histologically by their distinctive morphology and by visualisation of placental alkaline phosphatase immunoreactivity. RESULTS: The majority of carcinoma in situ (CIS) cells were immunopositive for IGF I, whereas no CIS cells stained for IGF II. Of all the IGF binding proteins investigated, CIS cells showed intense immunoreactivity for IGF binding protein 5 and lower expression of all other IGF binding proteins. CONCLUSIONS: These results suggest that the action of IGF binding protein 5 in CIS cells may modulate the activity of IGF I. This may be related to a proliferative advantage that could facilitate tumour development.

Adult↗
PubMed1997

Elevated human chorionic gonadotropin concentrations in the testicular vein and in peripheral venous blood in seminoma patients. An analysis of various parameters.

OBJECTIVE: Human chorionic gonadotropin (HCG) elevations in the testicular vein (TV) are correlated with those in the cubital vein (CV). Their significance was tested regarding various prognostic parameters. METHOD: Within the framework of a large multicentre study to assess the prognosis of HCG-positive seminomas 726 eligible patients were recruited from 1986 to 1991. A total of 378 had elevated and 348 had normal HCG measured in the CV. In 144 patients samples were taken from the TV. Histological diagnosis of seminoma was confirmed by two reference pathologists. Three groups (group I: elevated HCG in CV and normal or elevated HCG in TV; group II: normal HCG in CV and elevated HCG in TV; group III: normal HCG in CV and normal or unknown HCG in TV) were compared in relation to the presence or absence of metastases, stage of the disease, size of the primary tumour, pT category, vascular invasion and lactate dehydrogenase. RESULTS: Of the TV serum samples, 85% were HCG-positive. Regression analysis revealed higher values in the TV compared to the CV according to the following equation: HCGTV = 520 + 1.12 x HCGCV, R = 0.766, with a mean variation of 14%. Patients in group I had significantly higher stages and larger primary tumours than patients with normal HCG in the CV, irrespective of the HCG values in the TV blood (groups II and III). Therefore, HCG is associated with tumour mass. No differences of statistical significance were found regarding T category, vascular invasion and lactate dehydrogenase. There were no differences between groups II and III. CONCLUSION: Only HCG values of the CV are associated with known adverse-prognostic factors of seminomas, such as metastases and size of the tumour. HCG in the TV adds no further information for the clinical assessment of patients with seminoma.

Austria↗
PubMed1997

Effects of serial percutaneous application of carbon dioxide in intermittent claudication: results of a controlled trial.

In a prospective, controlled clinical trial, serial application of carbon-dioxide-enriched water was compared with fresh water. Twenty-four patients with peripheral arterial occlusive disease (stable claudication) were randomly allocated to one of two serial intervention groups, lower extremities immersed in either fresh water or in CO2-enriched water (1000 mg CO2/kg) water under standardized conditions (temperature, 33 degrees C; depth, 40 cm; immersion time, 30 min; five times a week over 4 weeks). The serial application of carbon-dioxide-enriched water increased arterial peak flow (reactive hyperemia), transcutaneous oxygen tension (basal value and half-recovery-time), and pain-free walking distance. The serial fresh water application did not change these values. The authors conclude that serial carbon dioxide application can be clinically effective in patients with arterial obstructions in the lower extremities.

Adult↗
PubMed1997

Analysis of the DCC tumor suppressor gene in testicular germ cell tumors: mutations and loss of expression.

Inactivation of the DCC (Deleted in Colon Carcinoma) tumor suppressor gene by allelic loss and/or reduced expression is associated with the development of colon cancer, gliomas, gastric and prostatic malignancies. In a total cohort of 51 testicular germ cell tumors (GCT) of different histologies we analyzed restriction fragment length polymorphism (RFLP) for DCC at two specific DNA sites in 37 GCT and DCC mRNA expression compared to that of the adjacent normal testicular tissue in 41 GCT, one Leydig cell tumor and one testicular metastasis of a non-small cell lung cancer (NSCLC). Two of 17 tumors (11.7%) informative for the Msp I polymorphic site of the DCC gene and 6/25 tumors (24.0%) informative for variable number of tandem repeat (VNTR) showed loss of heterozygosity (LOH). DCC expression was analyzed by semi-quantitative polymerase chain reaction after initial reverse transcription (RT-PCR). Thirty of 41 GCT (73.1%) and both, the Leydig cell tumor and the testicular metastasis of NSCLC, had a nearly complete or total loss of DCC mRNA expression. Six of 11 (54.5%) seminomas and 24/30 (80.0%) nonseminomas had this loss of expression. Twelve of 17 (70.5%) localized tumors, 9/13 (69.2%) tumors with lymph node involvement and 9/11 (82.2%) tumors with distant metastases showed decreased or absent DCC expression. This data suggests that inactivation of the DCC gene, especially the loss of DCC expression, is associated with the development and progression of human GCT.

Gene Expression Regulation, Neoplastic↗
PubMed1996

Toxicokinetics of isoprene in rodents and humans.

A physiological toxicokinetic model (PT model) was developed for inhaled isoprene in mouse, rat and man. Partition coefficients blood:air and tissue:blood were determined in vitro by a headspace method. Parameters of a saturable isoprene metabolism in B6C3F1 mice, Sprague-Dawley rats and volunteers were obtained from gas uptake experiments in closed systems, analyzed by means of a two-compartment model. Incorporation of these parameters into the PT model revealed that isoprene was metabolized not only in the liver but also in extrahepatic organs. Endogenous production of isoprene in man was quantified from experiments with volunteers breathing into a closed system. The PT model was validated for mice, rats and humans by comparing simulated values with data determined by other authors.

Adult↗