Biomedical subjects

V Waldmann

Publications and source records attributed to V Waldmann.

31 records · Page 2Linked to original sources

PubMed1998

Massive lethal cerebral bleeding in a patient with melanoma without intracranial metastasis.

The case history is reported of a patient with melanoma and advanced metastases, who died from massive cerebral bleeding. The lethal event was not caused by intracerebral metastasis but by thrombocytopenia. Depression of the bone marrow resulted from tumour infiltration of the skeleton, chemotherapy and vertebral irradiation. An increase of intracranial pressure triggered the cerebral bleeding, caused by haematemesis from a gastric metastasis directly preceding sudden somnolence.

Bone Neoplasms↗

PubMed1998

Absence of RAS and p53 mutations in thyroid carcinomas of children after Chernobyl in contrast to adult thyroid tumours.

Thyroid carcinomas of an additional series of 34 children exposed to radioactive fall-out after the Chernobyl reactor accident were analysed for mutations in the H-, K- and N-RAS and the p53 gene. Allele-specific oligonucleotide hybridization, single-strand conformation polymorphism (SSCP) and direct sequencing did not disclose mutations in codons 12, 13 and 61 of RAS genes nor mutations in exons 5, 7 and 8 of p53. Considering the recently reported high prevalence of RET rearrangements of the PTC3 type in childhood tumours after Chernobyl (Klugbauer et al, 1995, Oncogene 11: 2459-2467), it follows that RET rearrangements are the most relevant molecular aberration in these radiation-induced tumours. RAS or p53 mutations do not play a role in childhood thyroid carcinogenesis after Chernobyl.

Adult↗

PubMed1998

Non-human immunodeficiency virus Kaposi's sarcoma can be effectively treated with low-dose interferon-alpha despite the persistence of herpesvirus-8.

Three patients, negative for human immunodeficiency virus (HIV), with histologically and polymerase chain reaction-proven non-HIV Kaposi's sarcoma who received low-dose interferon (IFN) as first-line treatment because of disseminated symptomatic disease are reported. Applying 3-18 million IU of IFN-alpha 2a per day, 3 days a week, subcutaneously for 8-20 months, major responses were achieved in all three cases. Tumour regression was observed within 4 months and has continued for 57 and 18 months to date (cases 1 and 2, respectively). Influenza-like symptoms, including fever, headaches and fatigue, were mild side-effects. However, in the third patient interferon injections had to be stopped because of hepatic enzyme elevation. Including this case report, 27 non-HIV Kaposi's sarcoma patients subcutaneously treated with IFN-alpha have been reported in literature. Most therapy regimens included 3-18 million IU IFN-alpha per day for 3 days a week. Twenty of 27 patients, or 74%, responded to therapy, whereas seven patients or 26% had stable or progressive disease. Relapse after IFN withdrawal can occur but is frequently delayed and limited, as in case 1. Following the response to IFN treatment, human herpesvirus-8 DNA was detected in the blood mononuclear cells of all three patients, possibly contributing to future relapses.

Antineoplastic Agents↗

PubMed1997

Absence of G(s)alpha gene mutations in childhood thyroid tumors after Chernobyl in contrast to sporadic adult thyroid neoplasia.

Heterotrimeric G proteins participate in the signal transduction cascade. Adult thyroid tumors have been shown to harbor specific point mutations in codons 201 and 227 of the G(s)alpha subunit of the adenylate cyclase stimulator. This protein affects the GDP/GTP turnover and finally results in an enhanced activation of G(s) and thus adenylate cyclase. We attempted to find out if G(s)alpha gene mutations were present in thyroid tumors of children from Belarus after the Chernobyl nuclear accident. Paraffin sections of 20 thyroid tumors were used for PCR amplification by oligonucleotide intron primers flanking exons 8 and 9, encompassing codon 201 and 227, respectively. By direct sequencing of the 274-bp amplification product, we did not detect any mutations of the G(s)alpha gene in codon 201 or 227. In contrast to thyroid neoplasia of adults, G(s)alpha gene mutations do not play a role in the development of childhood thyroid tumors after the Chernobyl reactor accident.

Carcinoma, Papillary↗

PubMed1997

Analysis of the T cell response to tumor and viral peptide antigens by an IFNgamma-ELISPOT assay.

We have established a sensitive ELISPOT assay measuring interferon gamma (IFN gamma) release on a single-cell basis to detect influenza peptide-specific CD8+ T cells in uncultured peripheral blood mononuclear cells (PBMC). Using this method, we studied the T cell response to HLA-A1 and HLA-A2.1 binding peptide epitopes derived from the MAGE-1 and MAGE-3 proteins, from the melanoma-associated antigens tyrosinase, Melan-A/MART-1 and gp100, and from influenza proteins in stage IV melanoma patients and healthy controls. In 18 of 24 HLA-A2-positive donors (75%), but only in 9 of 25 HLA-A2-positive melanoma patients (36%) T cells reactive with the influenza matrix peptide were demonstrated (p = 0.007). T cells responding to one or several of the melanoma-associated peptides were detected in 5 of 25 HLA-A2-positive patients with metastatic melanoma. Four of these 5 patients had been treated with interleukin-2- and IFN alpha-containing therapy. Two of the 24 healthy donors had T cells reactive with the MART-1 27-35 peptide. No reactivity with the HLA-A1-binding peptides from MAGE-1 or MAGE-3 was detected in any of the HLA-A1-positive healthy controls or melanoma patients. These results show that the IFN gamma-ELISPOT assay is suitable to determine quantitatively T cells reactive with melanoma-associated and influenza peptide epitopes in uncultured PBMC. The failure to detect T cells responding to influenza in many melanoma patients with progressive disease may indicate an impairment of their T cell function.

Antigens, Neoplasm↗

PubMed1997

[Kaposi sarcoma in cyclosporin A therapy of actinic reticuloid].

A 76 year old patient with actinic reticuloid was treated with Cyclosporin A. 11 months after beginning the immunosuppressive therapy, he developed lymphoedema and livid nodular skin lesions of the right leg, which histologically showed Kaposi's sarcoma. After stopping the Cyclosporin A and intralesional therapy with Interferon alpha, no regression of the Kaposi sarcoma could be seen. The characteristics of Kaposi sarcoma arising during immunosuppressive therapy and the differences in incidence, risk groups and distribution pattern compared to the classic sporadic and the AIDS-related Kaposi sarcoma will be described. The development of Kaposi sarcoma during immunosuppressive therapy for actinic reticuloid has not been previously described.

Aged↗

PubMed1996

Proliferative heterogeneity of human renal cell carcinomas and prevalence of ras gene point mutations.

The variable prevalence and a possible stage-dependent increase of ras gene point mutations in human tumors might correspond to clonal growth advantages of ras-activated cells. Tumor areas with activated ras genes might thus differ in proliferative activity from those lacking ras gene activation. This hypothesis is studied in a series of human renal cell carcinomas that had been used previously for an analysis of proliferative compartments after post-operative vascular [3H]/[14C]thymidine perfusion [Rabes et al. (1979) Cancer 44: 799-813]. The growth fraction of different subcompartments of these tumors was studied by immunohistochemistry with mib1 antibody, recognizing a fixation- and embedding-resistant epitope of Ki-67 protein. Thirty subpopulations of 14 human renal cell carcinomas that exhibited a broad spectrum of proliferative activity were chosen for an analysis of the prevalence of K-ras point mutations in exon 1 by a mutation-enriching primer-mediated restriction-fragment-length-polymorphism analysis and/or direct sequencing of polymerase-chain-reaction-amplified material. The combined autoradiographic and immunohistochemical analysis confirmed the intra- and intertumoral proliferative heterogeneity. Compared to [3H]/[14C]thymidine labeling indices, mib1 labeling indices are higher. The ratio of mib1 to [3H]/[14C]thymidine labeling indices varies from 1.9 to 4.1 for the individual tumor subcompartments. However, neither in K-ras codons 12/13 nor in adjacent codons did we detect any mutations in the various tumor compartments. The results suggest that neither mode of proliferation nor type of differentiation is related to K-ras exon 1 point mutations in human renal cell carcinomas.

Adult↗

PubMed1996

What's new in ras genes? Physiological role of ras genes in signal transduction and significance of ras gene activation in tumorigenesis.

Ras gene mutations have been found with variable prevalence in different tumor types. While during the past decade a lot of information has been accumulated on the frequency of ras oncogene activation in tumors, the last two years brought considerable progress in elucidating molecular mechanisms of signal transduction for which cellular ras proteins are key elements. They transmit signals from upstream tyrosine kinases to downstream serine/threonine kinases ultimately leading to changes of gene expression cytoskeletal architecture, cell-to-cell interactions and metabolism. These signalling pathways are of interest for the physiological regulation of proliferation and differentiation in normal, as well as in cancer tissue. Mutational activation of cellular ras genes to transforming oncogenes is thought to promote cell growth even in the absence of extracellular stimuli, and may thereby contribute to the initiation and/or progression of tumors.

Animals↗

PubMed1994

[Piglet castration--pain sensation and pain elimination].

Electroencephalographic (EEG) recordings performed in piglets during Trapanal anaesthesia showed distinct changes in bioelectrical brain activity in some piglets when castration was carried out. Only an additional extradural anaesthesia seemed to interrupt the transmission of peripheral pain stimuli to the central nervous system. Based on the protocol used EEG did not reveal a marked response to noxious stimulation. Castration of piglets up to two weeks of age were performed during general anaesthesia with Trapanal or Disoprivan or local anaesthesia with Hostacain or without any anaesthesia. The different modes of anaesthesia have had no effects to postoperative wound healing and weight gain between groups as well as between males and females within single groups. With regard to insufficient analgesia and/or partially extreme secondary effects the application of investigated anaesthetic methods on the occasion of castration of piglets is not justifiable at present. Castration in piglets up to an age of two month without anaesthesia is allowed by the animal protection law. However, due to improved wound healing and decreased response to surgical stimulus we suggest to perform castration during the first 10 days after delivery.

Anesthesia↗

PubMed1993

Cell proliferation and prevalence of ras gene mutations in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumors.

Exposure of female inbred Sprague-Dawley Curl rats to intragastric 7,12-dimethylbenz(a)anthracene (DMBA) resulted in a variety of benign and malignant mammary tumors exhibiting a wide spectrum of proliferative activity as measured by [3H]-thymidine autoradiography. On the basis of earlier observations of 21% H-ras codon 61 mutations in DMBA-induced rat mammary tumors reported by Zarbl et al., the prevalence of this type of ras gene mutation was studied in relation to the rate of proliferation in individual benign and malignant tumors. In a series of 50 mammary tumors exhibiting highly different proliferation activities we did not detect any H-ras codon 61 mutations after allele-specific dot blot hybridization of PCR-amplified material obtained from paraffin sections. Neither mode of proliferation nor type of differentiation appears related to H-ras codon 61 mutations. The relevance of activated ras genes for rat mammary carcinogenesis appears restricted to model systems using N-methyl-N-nitro-sourea (MNU) as initiating carcinogen.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1992

Ras gene mutation-independent tumours in the intestine of the rat by a single dose of N-methyl-N-nitrosourea.

Aiming at a sequential analysis of the role of ras gene point mutations during intestinal carcinogenesis, we established an experimental rat tumour model using N-methyl-N-nitrosourea (MNU) as an initiating agent as this carcinogen has been found to induce rat mammary carcinomas with a high prevalence of ras gene mutations. MNU treatment of a total of 249 rats (25 or 50 mg/kg i.p.) in various combinations with partial hepatectomy, hydroxyurea infusion and/or phenobarbital exposure resulted in a high incidence of intestinal adenomas and carcinomas of different histological types, besides liver, soft tissue and auditory sebaceous gland tumours. With PCR-amplified DNA the prevalence of mutations of codon 12 and 61 of H-, K- and N-ras was determined in dot blots by hybridization with 32P-labelled allele-specific oligonucleotides. Ras gene point mutations were not observed in any of the 41 intestinal rat tumours randomly selected from various experimental groups. Considering the high prevalence of ras mutations in MNU-induced mammary carcinomas of the rat the observed complete lack of ras mutations in intestinal tumours induced in the rat by the same carcinogen suggests that organ-specific intraspecies differences in the mechanism of malignant transformation exist even for a heterolytically decomposing, direct acting carcinogen like MNU.

Animals↗

PubMed1990

[PCR: DNA amplification from histological sections].

Specific DNA sequences can be amplified from tissue material by means of the polymerase chain reaction (PCR) using oligonucleotides homologous to upstream and downstream flanking regions as primers for repeated cycles of Taq polymerase-mediated DNA synthesis (primer extension) in vitro. The amplification product provides the unique possibility to analyze genomic alterations (mutations, deletions, translocations) which may play a role during pathogenetic processes, or to detect heterologous (viral, bacterial) nucleic acids with maximum sensitivity. PCR with morphologically defined material from histologic sections gives the chance to bridge the gap between morphological description of a disease and the underlying molecular alteration. PCR from sections can be performed even from paraffin-embedded material of archival specimens. As an example a ras gene mutation analysis of human colorectal cancers and their metastasis and of human seminomas is presented. Only minute amounts of biological material are required for PCR, as exemplified with material punched from defined preneoplastic areas in rat liver cryostat sections. Using this material, not only a thorough mutational analysis of DNA of preneoplastic foci is possible after a simultaneous PCR amplification of various genomic sequences, but also an investigation of transcription activity after reverse transcription of mRNA into cDNA, as shown for c-myc expression during preneoplasia. The extremely high sensitivity of the method requires severe precaution with respect to contamination, and product control by Southern blots or sequencing. PCR from histological sections will become a valuable tool for analyzing molecular mechanisms of disease based on the classical morphological parameters of pathology.

Animals↗

PubMedDate not supplied

[Consumption coagulopathies following peritoneojugular bypass. Prevention by a heparin-antithrombin III combination].

Consumption coagulopathy (CIVD) is a frequent complication of peritoneojugular bypass operation. Preventive treatment applied involves low-dose heparin (1.5 mg/kg/d) to maintain an antithrombin III concentration of at least 65%. Results are evaluated in 6 patients treated by 7 bypass operations. A biologic CIVD developed in 2 cases (29%) but no clinical coagulopathy was observed. This incidence is less than that usually reported, a literature review indicating a biologic coagulopathy in 65% of cases, with clinical evidence in 12.5%. Furthermore, patients with spontaneously elevated AT III levels did not develop CIVD while, in contrast, sufficiently high concentrations of AT III could not be maintained in the 2 patients with coagulopathy. These findings suggest the interest of prevention of a CIVD by the use of this procedure.

Adult↗