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Biomedical subjects

M Werner

Publications and source records attributed to M Werner.

At least 271 records · Page 15Linked to original sources
PubMed1993

Prognostic significance of Ki-67 immunostaining in nonmetastatic renal cell carcinoma.

PURPOSE: Fresh tissue samples from nonmetastatic renal cell carcinoma (RCC) patients were analyzed by Ki-67 immunostaining to determine the prognostic significance of this tumor-biologic parameter. MATERIALS AND METHODS: In a prospective study, Ki-67 immunostaining was performed on frozen sections of histologically proven node-negative RCC from 58 patients operated on between 1986 and 1988 to examine the method's prognostic value and its association with other clinicopathologic parameters such as tumor stage (pT) and grade (G). RESULTS: The percentage of Ki-67-positive cells (ie, the proliferation rate [PR]) of all 58 RCC tumors ranged between 1% and 23%, while normal renal tissue exhibited PRs up to 2% only. In almost all cases, the highest PRs were observed in the peripheral zone of malignant tissue close to the normal renal tissue. PR did not correlate with pT, whereas a strongly significant correlation was observed between PR and G, as well as recurrence rate. Twenty-three of 58 patients (39.6%) developed tumor recurrence. Disease-free survival was strongly associated with PR. In a multivariate analysis, G and PR were independent prognostic markers. CONCLUSION: The tumor-specific PR obtained by Ki-67 labeling seems to be an independent marker to describe the proliferative activity and aggressiveness of individual tumors. This new tumor-biologic marker detects RCC patients at high risk for recurrent disease, especially in those cases with identical pT and G.

Adult↗
PubMed1993

Correlation of human papillomavirus DNA detection in biopsies of cervical lesions and the corresponding cervical swabs with the same method of in situ hybridization.

Human papillomavirus types 16 and 18 (HPV 16/18) are considered to play an important role in the pathogenesis of cervical intraepithelial neoplasia (CIN) and invasive cancer of the uterine cervix. The in situ hybridization (ISH) is the only method demonstrating a correlation between histopathological findings and the presence of specific HPV DNA, but its sensitivity is limited. To determine whether or not the mode of sample taking contributes to the reported HPV prevalence with this method two observers examined the cervical swabs and tissue sections of 41 CIN lesions independently with the same commercial ISH kits (PathoGene/Enzo Diagnostics Inc., New York). HPV prevalences were almost identical in both sample groups (21/41 HPV positive tissue sections and 23/41 HPV positive swabs). 30/41 samples (73%) showed identical HPV-ISH results in the biopsy and the corresponding swab. There was only one CIN 1 lesion with different associated HPV types in the corresponding tissue section and cervical swab. By accumulating the results of both sample groups 27 out of 41 CIN lesions had either an HPV positive swab or biopsy or both. The percentage of HPV 16/18 positive samples increased with the severity of the associated lesion.

Adult↗
PubMed1993

Clinical utility and validation of emerging biochemical markers for mammary adenocarcinoma.

The clinical utilities of the emerging biochemical markers for mammary adenocarcinoma CA 15-3, CA 549, CA M26, CA M29, and MCA (mucin-like carcinoma-associated antigen) were assessed by a formal rating according to six desirable marker characteristics. All five indicators similarly have good specificities but limited sensitivities. As a consequence, these markers mainly meet just two desirable criteria: their frequency and degree of expression reflect tumor burden and prognosis, and they may correlate with therapeutic results. The validation of these assay properties by clinical trials was evaluated by another rating system, designed to assess proband sample selection, restrictions on allowable observations, and choice of statistical descriptors. By these benchmarks, the estimates of the prior probabilities of test outcome (sensitivity and specificity) are reasonably definitive, but conclusive judgments about the posterior probabilities of test outcome ("predictive values") and about values and costs associated with testing are not possible. Three approaches to enhance the limited clinical utility of biochemical breast cancer markers are considered: shifts of the diagnostic decision threshold, marker panels, and sequential testing. However, none of these strategies improves the described performance characteristics.

Adenocarcinoma↗
PubMed1993

Can medical decisions be standardized? Should they be?

After a variety of regulatory and payment schemes have failed to stem the rising tide of health care cost, the Omnibus Budget Reconciliation Act of 1989 mandates the creation of a system of decision rules called practice parameters for appropriate medical action in many circumstances. A large body of practice guidelines already exists, but lacks the internal coherence required of a policy tool. Professional organizations therefore have developed attributes to achieve uniform style. However, little has been said or published about the constraints that might be imposed on the structure and content of an efficient and coherent system. The arguments presented here lead to the following conclusions: (a) process control is an inefficient tool to manage outcome--standards should reflect product control; (b) guidelines that proscribe are more likely to be supported by scientific data and consensus than those that prescribe; (c) the decision thresholds contained in such directives are policy choices rather than scientific imperatives; (d) neither decision analysis nor artificial intelligence is likely to readily influence medical decisions; and (e) as suggested by operations research, the development of practice parameters should concentrate on issues of therapeutic management in preference to issues of diagnostic activity.

Chemistry, Clinical↗
PubMed1993

[Injuries of the thoracic skeleton].

Injuries of the thoracic skeleton are an important indicator of other, relevant traumatic changes after a polytrauma. Most fractures occur in the ribs, followed by fractures of the clavicle, the scapula and the sternum. Because of their high kinetic energy, car accidents are the main reason for thoracic fractures. The basic radiologic tool is the a.p. projection of the thorax in supine position; in addition, other conventional x-ray examinations or computed tomography are performed. Most thoracic fractures are treated conservatively, only in few cases (instability of the thorax, risk of pseudoarthrosis, incongruence of joint surfaces) surgical procedures are used.

Clavicle↗
PubMed1992

A new histological embedding method by low-temperature polymerisation of methyl methacrylate allowing immuno- and enzyme histochemical studies on semi-thin sections of undecalcified bone marrow biopsies.

A new procedure of embedding in methyl methacrylate (MMA) is introduced, which enables immunostaining by preservation of cellular epitopes. This could be achieved by reduction of polymerisation temperature from ca. 60 degrees C to 22 degrees C within the core of tissue blocks. Reduction of the polymerisation temperature is due to destabilisation of acrylate monomer, reduction of catalyst, exclusion of molecular oxygen, chemical initiation and reduction of environmental temperature. This results in good preservation of antigens and enzymes in the haematopoietic and lymphatic tissue of bone marrow as well as lymphoid, epithelial and mesenchymal markers in other tissues, comparable to paraffin embedding. Results are demonstrated by application of monoclonal and polyclonal antibodies and by demonstration of enzyme activity conventionally used in haematology.

Biopsy↗
PubMed1992

Effects of cytokines on growth in vitro of primary human renal cell carcinoma.

In clinical trials different haematopoietic active cytokines such as granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) have been proven to alleviate myelosuppressive side effects of intensive chemotherapy in different non-urological malignancies. On the other hand, these cytokines can directly stimulate the proliferation of cells originating from some non-urological tumours. To clarify the impact of these cytokines on the proliferative behaviour of human renal cell carcinoma (RCC), 29 previously untreated RCC tumours were prepared for culturing in vitro using the cell cluster technique. The success rate for growth in vitro was 82.8% (24/29). The malignant renal cells were treated with different cytokines (GM-CSF, G-CSF and interleukin-3) in different dosages. Cell number and proliferation rates detected by immunostaining were used for treatment evaluation. A dosage-dependent stimulation of cell growth could not be observed compared to untreated cells. From the data presented in this study, proliferative stimulation of RCC by administering colony-stimulating factors in clinical trials cannot be assumed.

Carcinoma, Renal Cell↗
PubMed1992

Chromosome analyses in patients with myelodysplastic syndromes: correlation with bone marrow histopathology and prognostic significance.

Chromosome analyses of bone marrow and peripheral blood cells were performed in a total of 51 patients with myelodysplastic syndromes (MDS) simultaneously with histopathological examination of resin-embedded bone marrow biopsies. Diagnosis of MDS was established by histopathology according to the French-American-British (FAB) classification, and reassessed by haematological data and clinical course. Clonal karyotypic changes were found in 30 of the 51 patients (59%): in 15 of 19 (79%) patients with refractory anaemia, 7 of 11 (64%) with refractory anaemia and excess of blasts (RAEB), 6 of 10 (60%) with RAEB in transformation, and 2 of 11 (18%) with chronic myelomonocytic leukaemia. The following three features of the histopathology revealed positive correlations with karyotype abnormalities: all cases of myelofibrosis in MDS (7/51) were accompanied by chromosome aberrations, microforms of megakaryocytes with reduced nuclear lobulation were observed in 18 of 30 cases with karyotype changes, and hypocellularity of haematopoiesis was associated with aberrations of chromosome 7 in 2 of 4 cases. No positive correlations were revealed between abnormal karyotypes and the transformation to acute leukaemia. The survival times were significantly decreased in patients with complex (3 and more) karyotype changes, when compared with patients with single (1-2) chromosome aberrations or normal karyotype, independently of the FAB classification.

Aged↗
PubMed1992

Immunohistochemical examination of routinely processed bone marrow biopsies.

Immunohistochemistry was performed on paraffin sections of 169 bone marrow biopsies fixed in a buffered methanol-formalin solution and decalcified with EDTA. The biopsies included specimens with normal hematopoiesis, and specimens that were affected by various hematological disorders as well as some metastatic carcinomas. The results demonstrate that a wide spectrum of antigens was preserved in routinely processed bone marrow biopsies, even after long-term fixation up to 12 days. Markers for granulopoietic cells were lysozyme, elastase, DAKO-M 1, and MT 1. Megakaryopoiesis was stained with glycoprotein IIIa, von Willebrand factor, and Ulex europaeus agglutinin (UEA), and erythropoiesis with LN 1. Normal lymphocytes as well as lymphoma cells of all non-Hodgkin's lymphomas tested were positive for leukocyte common antigen (LCA), and at variable degree, for MB 1, 4 KB 5, LN 1, LN 2, UCHL 1, or MT 1. Reed-Sternberg and Hodgkin's cells in Hodgkin's lymphomas were reactive with Ber-H 2, LN 2 and Dako-M 1. In plasma cell disorders, staining for immunoglobulin light chains gave best results. Metastatic carcinomas showed predominantly staining with EMA, and KL 1. A selected panel of specific cell markers is proposed, which proved to be helpful in routine bone marrow diagnosis in most cases.

Biopsy↗
PubMed1992

Antimicrobial susceptibilities of Campylobacter jejuni and Campylobacter coli isolated in Sweden: a 10-year follow-up report.

Resistance to erythromycin and doxycycline and more recently to fluoroquinolones has been reported to occur in Campylobacter spp. both in vitro and in patients treated with these antibiotics. The frequency of resistance to 14 antimicrobial agents in Campylobacter jejuni and Campylobacter coli isolated from patients infected in Sweden or abroad is described. For some agents, a comparison of susceptibility in strains of Campylobacter spp. isolated in 1978 with those isolated in 1988 is made. No general increase in in vitro resistance to antibiotics commonly used for the treatment of human gastroenteritis caused by C. jejuni or C. coli has occurred during the last 10 years in Sweden, which might be a consequence of strict antibiotic control. The numbers of strains from 1988 to 1989 resistant to ciprofloxacin and to norfloxacin included in this study (0.7 and 1.4%, respectively) are still fewer than those that were resistant to erythromycin (7.3%) or doxycycline (12.4%). There is, however, since 1989 to 1990 an indication of increasing resistance to these antibiotics.

Anti-Bacterial Agents↗
PubMed1992

RPC82 encodes the highly conserved, third-largest subunit of RNA polymerase C (III) from Saccharomyces cerevisiae.

RNA polymerase C (III) promotes the transcription of tRNA and 5S RNA genes. In Saccharomyces cerevisiae, the enzyme is composed of 15 subunits, ranging from 160 to about 10 kDa. Here we report the cloning of the gene encoding the 82-kDa subunit, RPC82. It maps as a single-copy gene on chromosome XVI. The UCR2 gene was found in the opposite orientation only 340 bp upstream of the RPC82 start codon, and the end of the SKI3 coding sequence was found only 117 bp downstream of the RPC82 stop codon. The RPC82 gene encodes a protein with a predicted M(r) of 73,984, having no strong sequence similarity to other known proteins. Disruption of the RPC82 gene was lethal. An rpc82 temperature-sensitive mutant, constructed by in vitro mutagenesis of the gene, showed a deficient rate of tRNA relative to rRNA synthesis. Of eight RNA polymerase C genes tested, only the RPC31 gene on a multicopy plasmid was capable of suppressing the rpc82(Ts) defect, suggesting an interaction between the polymerase C 82-kDa and 31-kDa subunits. A group of RNA polymerase C-specific subunits are proposed to form a substructure of the enzyme.

Amino Acid Sequence↗
PubMed1992

Inactivation of the protein phosphatase 2A regulatory subunit A results in morphological and transcriptional defects in Saccharomyces cerevisiae.

We have determined that TPD3, a gene previously identified in a screen for mutants defective in tRNA biosynthesis, most likely encodes the A regulatory subunit of the major protein phosphatase 2A species in the yeast Saccharomyces cerevisiae. The predicted amino acid sequence of the product of TPD3 is highly homologous to the sequence of the mammalian A subunit of protein phosphatase 2A. In addition, antibodies raised against Tpd3p specifically precipitate a significant fraction of the protein phosphatase 2A activity in the cell, and extracts of tpd3 strains yield a different chromatographic profile of protein phosphatase 2A than do extracts of isogenic TPD3 strains. tpd3 deletion strains generally grow poorly and have at least two distinct phenotypes. At reduced temperatures, tpd3 strains appear to be defective in cytokinesis, since most cells become multibudded and multinucleate following a shift to 13 degrees C. This is similar to the phenotype obtained by overexpression of the protein phosphatase 2A catalytic subunit or by loss of CDC55, a gene that encodes a protein with homology to a second regulatory subunit of protein phosphatase 2A. At elevated temperatures, tpd3 strains are defective in transcription by RNA polymerase III. Consistent with this in vivo phenotype, extracts of tpd3 strains fail to support in vitro transcription of tRNA genes, a defect that can be reversed by addition of either purified RNA polymerase III or TFIIIB. These results reinforce the notion that protein phosphatase 2A affects a variety of biological processes in the cell and provide an initial identification of critical substrates for this phosphatase.

Amino Acid Sequence↗
PubMed1992

Effect of mutations in a zinc-binding domain of yeast RNA polymerase C (III) on enzyme function and subunit association.

The conserved amino-terminal region of the largest subunit of yeast RNA polymerase C is capable of binding zinc ions in vitro. By oligonucleotide-directed mutagenesis, we show that the putative zinc-binding motif CX2CX6-12CXGHXGX24-37CX2C, present in the largest subunit of all eukaryotic and archaebacterial RNA polymerases, is essential for the function of RNA polymerase C. All mutations in the invariant cysteine and histidine residues conferred a lethal phenotype. We also obtained two conditional thermosensitive mutants affecting this region. One of these produced a form of RNA polymerase C which was thermosensitive and unstable in vitro. This instability was correlated with the loss of three of the subunits which are specific to RNA polymerase C: C82, C34, and C31.

Amino Acid Sequence↗
PubMed1992

[Borderline between Hodgkin and non-Hodgkin lymphomas with unfavorable clinical course: a clinical, histological and immunohistochemical analysis of 33 cases within the German Hodgkin Lymphoma Study].

Reevaluation of diagnostic biopsies from 502 patients who entered the German Hodgkin Therapy trial was performed by a panel of four pathologists. Classification revealed 90% of unambiguous Hodgkin-lymphomas (HL), 1.6% of Non-Hodgkin-lymphomas (NHL) and 8.4% of cases difficult to evaluate, reflecting to the well-known problem of the border between these 2 groups of lymphoma. As these cases had the worst prognosis, a second attempt of reclassification, including immunohistochemical studies, was made, resulting in final classifying of 25% of these cases as NHL, 50% as HL, and 25% as further unclassifiable. The most common differential diagnostic problem was separating pleomorphic nodular sclerosing HL from large cell NHL's and HL with rather few Hodgkin- or Reed-Sternberg-cells from Lennerts lymphoma or angioimmunoblastic lymphadenopathy. Immunohistochemistry was helpful for the differential diagnostic decisions in these individual cases. A very high percentage of these problem cases had initially entered the trial as lymphocyte depleted HL, and the large majority of deaths came from the large cell NHL group.

Diagnosis, Differential↗