Biomedical subjects

R Fischer

Publications and source records attributed to R Fischer.

At least 325 records · Page 18Linked to original sources

PubMed1994

Angioimmunoblastic lymphadenopathy type of T-cell lymphoma and angioimmunoblastic lymphadenopathy: a clinicopathological and molecular biological study of 13 Chinese patients using polymerase chain reaction and paraffin-embedded tissues.

The morphological classification of angioimmunoblastic lymphadenopathy (AILD) or T-cell lymphoma of AILD-type (AILD-TCL) is still a subject of considerable difficulty and controversy. The aim of the current study was to examine the value of clinical, morphological, immunohistochemical variables in paraffin-embedded tissues in predicting the clonality of the respective lesion. Fifteen lymph node biopsies derived from 13 patients from Chengdu, China, were diagnosed as AILD or AILD-TCL and included in this study. The specimens were examined using a panel of monoclonal antibodies and a scoring system of morphological features. Clonality of the paraffin-embedded material was investigated using a novel polymerase chain reaction-technique to amplify rearranged T-cell receptor (TCR)-gamma sequences. Additional experiments were carried out to investigate the presence of clonal rearrangements of the immunoglobulin heavy chain (IgH) locus. We found clonal rearrangements of the TCR-gamma locus in 9 out of 15 lymph node biopsies. In 3 patients, the predominant cell clones carried clonal IgH and TCR-gamma rearrangements whereas 1 patient with polyclonal TCR-gamma pattern displayed IgH-monoclonality. The statistical evaluation of morphological and immunohistochemical data indicated that no single variable was able significantly to predict the clonality of the lesion. Furthermore, demonstrable clonality for the TCR-gamma or the IgH loci of a lesion did not correlate with a bad clinical course. Our data correlate with findings of other studies investigating AILD-TCL in Caucasian populations.

Adult↗

PubMed1994

Stability of genomic DNA fragment patterns in methicillin resistant Staphylococcus aureus (MRSA) during the course of intra- and interhospital spread.

The analysis of genomic DNA fragment patterns has revealed as a powerful tool for strain discrimination in Staphylococcus aureus; for use as an epidemiological marker, stability during the course of an outbreak is an essential prerequisite. Genomic DNA fragment patterns (SmaI restriction, pulsed-field electrophoresis) of four different epidemic MRSA strains were compared along with intra- and interhospital and country-wide spread over more than 12 months in Germany. Strain I was isolated from infections in 8 hospitals. In one hospital a subclone arised which differed from the original strain by 4 fragments. Strain II was spread among 4 hospitals, isolates from three of these hospitals exhibited a variability of one to three fragments in the 150-200 kb range. Two hospitals in the Hannover-area were affected by strain III; in 17 isolates of this strain a variability up to three fragments was found in the 170-200 kb range. Strain IV was isolated from 19 cases of infections in 3 hospitals in Berlin. The fragment patterns were completely stable. When S. aureus strains are typed by genomic DNA fragment patterns, a variability in a definite range of molecular masses during the course of an epidemic should be taken into consideration.

Cross Infection↗

PubMed1994

The importance of sonography in the diagnosis of septic complications following spinal surgery.

The detection of infection after surgery on the thoracic and lumbar spine is difficult due to the anatomical circumstances. Clinical symptoms, laboratory findings, and most radiological techniques are of limited diagnostic value. Among other benefits, sonography offers the advantage of early postoperative examination, even with metal implants in the operated area. In a retrospective study, 27 patients with clinically suspicious wounds were evaluated by sonography in the postoperative follow-up; all cases were verified by puncture and/or operative revision. Eleven cases turned out to be hematomas, and 16 cases were found to be infections. Accumulations of fluid, however, could not be differentiated by the established sonomorphological criteria such as internal echo structures, septation, demarcation from the environment, and reaction of the surrounding tissue. Ultrasonically guided transcutaneous needle aspiration biopsy served to differentiate the local findings and to establish the diagnosis and therefore is required as an obligatory method of investigation.

Adult↗

PubMed1994

[Determination of clonality in lymphoproliferative diseases using polymerase chain reaction].

The diagnosis of lymph node lesions frequently requires the employment of additional studies. Lineage and clonality can be regarded as the most crucial diagnostic parameters. In some cases the diagnosis remains ambiguous even after immunohistochemistry and molecular biologic techniques have to be applied. These molecular biologic techniques are based on specific rearrangements of the immune genes that occur during T- and B-cell development. Whereas Southern blotting has become a standardized and reliable means for the detection of lineage and clonality, the limited availability of fresh frozen material frequently restricts its clinical applicability. The polymerase chain reaction has facilitated the investigation of immune gene rearrangements in formalin-fixed and paraffin-embedded tissue samples. This communication reviews the recent developments in this field.

Chromosome Aberrations↗

PubMed1994

Incidence of Epstein-Barr virus bcl-2 expression and chromosomal translocation t(14;18) in large cell lymphoma associated with paragranuloma (lymphocyte-predominant Hodgkin's disease).

Seven cases of large cell lymphoma (LCL) developing simultaneously or secondarily to lymphocyte-predominant Hodgkin's disease (nodular paragranuloma [NP]) were investigated for the presence of Epstein-Barr virus genomic material and the chromosomal translocation t(14;18) involving the major breakpoint region of the bcl-2 gene using the polymerase chain reaction on paraffin-embedded material. The translocation t(14;18) and Epstein-Barr virus could not be demonstrated in any case. The expression of the bcl-2 oncogene product was investigated using immunohistochemistry. Only in one case were the lymphocytic and histiocytic cells positively stained with the bcl-2 antibody, whereas the associated LCL demonstrated a completely negative immunoreaction. In another case the LCL had a positive immunoreaction with this antibody and the corresponding lymphocytic and histiocytic cells were completely negative. We conclude that Epstein-Barr virus infection is rare or absent in NP and in the LCLs associated with NP. The chromosomal translocation t(14;18) does not seem to be a factor in the transformation of NP into LCL.

Adult↗

PubMed1994

Epidemiological data and costs of burn injuries in workers in Switzerland: an argument for immediate treatment in burn centres.

A complete statistical evaluation of epidemiological data and costs of burn injuries in 1984 with a follow-up for 5 years is presented, considering a collective of 1.77 million workers in Switzerland. The majority of burns are minor injuries; only about 5 per cent of the burn victims are admitted to a hospital, 0.2 per cent died. Burn injuries at work are rare, mainly owing to strict safety measures. Only one-fifth of the costs caused by burns are due to medical treatment. All other expenses result from continuation of payments of salaries and annuities. The treatment of the few severely burned patients in burn units produces effective costs which are higher than the tariff paid by the insurance. Even so, the predominant portion of the enormous costs is taken up by wages while off work and annuities. As our conclusion we stress the importance of primary care for all severe burns including all burns of the hands in a specialized centre. Any economic effort for primary burn treatment, however high it may be, is justified if the duration of rehabilitation and invalidity can be reduced.

Accidents, Occupational↗

PubMed1994

Liver iron quantification: studies in aqueous iron solutions, iron overloaded rats, and patients with hereditary hemochromatosis.

For the noninvasive liver iron quantification by MRI in human iron overload diseases, fundamental proton relaxation mechanisms were studied in aqueous solutions with ferritin and other iron compounds, in experimentally iron overloaded rats, and in patients with iron overload diseases. MR-relaxation rates as a function of iron concentrations in the range of 0-7.5 mg Fe/g aqueous iron solutions, 0-5.4 mg Fe/g rat liver in vivo, and 0.16-4.9 mg Fe/g human liver in vivo were determined from multi- and sets of single-spin echo sequences (1.5 T imager). As predicted by theory, transverse relaxation rates (1/T2) in aqueous iron solutions, in liver tissue of rats, and in human liver tissue increased linearly with the iron concentration. A preliminary calibration for the liver iron quantification by MRI was performed from in vivo measurements of liver 1/T2-relaxation rates and liver iron quantification by atomic absorption spectroscopy in biopsies from 13 patients. With the single spin-echo method, precise in vivo liver iron quantification in humans also above 2.0 mg Fe/g liver tissue (T2 < 15 ms) should be accomplished on any imager with shortest spin-echo time available, at least TE < 20 ms.

Adult↗

PubMed1994

Proliferating cell nuclear antigen (PCNA) expression of megakaryocytopoiesis in normal human bone marrow and reactive lesions with special emphasis on HIV-myelopathy.

A morphometric analysis was performed on bone marrow trephine biopsies using sequential double-immunostaining, to evaluate endoreduplicative activity of megakaryocytopoiesis. A total of 104 marrow specimens were studied with employment of monoclonal antibodies PC10 (anti-proliferating cell nuclear antigen-PCNA) and Y2/51-CD61 (anti-platelet glycoprotein IIIa). In addition to the control group patients included non-specific inflammatory changes, HIV-myelopathy with normal or decreased platelet counts, idiopathic thrombocytopenic purpura (ITP), and finally reactive thrombocytosis (TH). To exclude an undue overexpression of PCNA, in a comparative pilot study we also applied MIB1 (Ki-67 antigen) on normal bone marrow specimens. In accordance with the various modalities of cell-cycle marker expression, no significantly different findings were disclosed. PCNA-labelling index was relatively low, ranging from 0.8 to 1.7% of the total megakaryocytopoiesis (promegakaryoblasts to mature platelet-shedding megakaryocytes). A significant relationship between megakaryocyte size and PCNA-expression was determinable. This implies that some of the cases with a prevalence of small megakaryocytes, like ITP, have the tendency to show a higher proportion of positively-stained cells. Moreover, this feature confirms a hypothesis postulating a decrease in the time for DNA-synthesis (S-phase) and a relative prolongation of the G1/G2-phases of the cell-cycle at higher ploidy levels (large-sized megakaryocytes). On the other hand, it may be speculated that some of the hyperpolyploid giant megakaryocytes may have reached their endstage of endoreduplication and enter into G0-phase. In comparison with the control group and the other entities under study, a significant reduction of PCNA-reactivity was recognizable in HIV-myelopathy accompanied by thrombocytopenia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

Factors influencing lymph node infiltration in primary gastric malignant lymphoma of the mucosa-associated lymphoid tissue.

The spread of primary gastric non-Hodgkin's lymphomas of the mucosa-associated lymphoid tissue (MALT) to the perigastric lymph nodes is a very important step concerning the prognosis of these tumours. In order to evaluate the parameters that influence the infiltration of the lymph nodes we retrospectively investigated 145 surgical specimens with gastric MALT lymphoma. The involved factors, i.e. depth of infiltration, degree of malignancy, and largest tumour diameters were strongly intercorrelated and partly showed significant correlations with the lymph node infiltration as well. Further statistical analysis by means of logistic regression revealed that depth of infiltration was the only parameter that remained significantly correlated with lymph node infiltration. Our data further support the notion that the depth of infiltration is a very important prognostic factor in MALT lymphomas. This could contribute to the explanation as to why the so-called early lymphomas with an infiltration limited to mucosa and submucosa have a much better prognosis than more advanced tumours. Our data thus support the thesis that gastric MALT lymphomas show clinicopathologic similarities with gastric carcinomas. We suggest that the depth of infiltration should be included in the pathological reports concerning primary gastric lymphomas of the MALT.

Adult↗

PubMed1994

A light- and temperature-entrained circadian clock controls expression of transcripts encoding nuclear proteins with homology to RNA-binding proteins in meristematic tissue.

To investigate physiological processes generated by endogenous circadian rhythms on the molecular level, we have identified clock-controlled genes in the long-day plant Sinapis alba L. A cDNA library was differentially screened using cDNA probes representing transcripts expressed at either the middle of the light period or the middle of the dark period. Two closely related groups of transcripts, Sagrp1 and Sagrp2, controlled by a circadian rhythm have been isolated. RNA blot analysis verified that transcript levels oscillate in plants grown in light/dark cycles with maxima between 'Zeitgeber' time (zt)8 and zt12 (8-12 h after onset of illumination) and minima around zt20. Steady-state mRNA levels continue to oscillate in plants shifted from light/dark cycles to constant light. No synchronous mRNA oscillations are found in plants grown from seed in constant light at constant temperature, suggesting that the clock has to be entrained initially. In contrast, when plants grown in constant light are exposed to rhythmic temperature shifts oscillations of steady-state Sagrp mRNA levels are induced, indicating that temperature acts as an alternative external stimulus (zeitgeber) other than light to entrain the oscillator. In situ hybridization reveals that both transcript groups are expressed predominantly in meristematic and growing tissue. Strong expression is observed in the leaf primordia of the shoot apex, the procambial strands, cambium and in all cell layers of young leaves around zt12. In contrast, little or no signal is found on tissue sections isolated at zt20. This indicates that the oscillator(s) regulating Sagrp transcript fluctuations operate(s) synchronously in different organs. For both transcript groups cDNAs were isolated corresponding to unspliced pre-mRNAs or to transcripts generated by the use of a second 5' splice site. The cDNAs corresponding to the fully spliced transcripts contain open reading frames for polypeptides of 16 kDa, each containing a putative N-terminal RNA recognition motif and a C-terminal region rich in glycine. The predicted proteins show strong homology to an ABA-inducible glycine-rich protein from maize embryos and to the mammalian RNA-binding protein A1 of the heterogeneous nuclear ribonucleoprotein complex involved in pre-mRNA splicing. The SaGRP protein fluctuates with a very low amplitude over light/dark cycles. Immunogold labeling demonstrates the presence of the SaGRP protein within the nucleus of the investigated meristematic cells of young leaves.

Amino Acid Sequence↗

PubMed1994

Long-term follow-up in 206 infertility patients with polycystic ovarian syndrome after laparoscopic electrocautery of the ovarian surface.

In recent publications we have demonstrated that laparoscopic electrocautery of the ovarian surface (LEOS) is an effective method to reduce serum androgen concentrations, normalizing ovarian cycle length and the ovarian reaction to hormonal stimulation therapy in anovulatory patients with polycystic ovarian disease (PCOD). In this paper we show that these effects are not only temporary. Data from 206 patients undergoing LEOS and monitored for up to 72 months after surgery are evaluated; 145 patients achieved a total of 211 conceptions, giving a pregnancy rate of 70%, with a maximum of four conceptions in one patient. There were 38 early miscarriages (18%) and two late pregnancy losses as well as three ectopic implantations.

Adult↗

PubMed1994

Detection of T-cell clonality in paraffin-embedded tissues.

In lymph node diagnosis, difficulties are frequently encountered with the differential diagnosis of reactive and neoplastic T-cell proliferations. Immunohistochemistry is of limited use, and fresh frozen material for DNA studies is not available in many cases. We have established a polymerase chain reaction (PCR) technique to amplify rearranged T-cell receptor (TCR)-gamma sequences from paraffin-embedded material. Our method differs from other techniques previously described in that it uses four sets of family-specific variable (V)gamma primers. Clonality of the investigated T cells is reflected not only by the varying lengths of amplified products but also by differences in the relative amount of rearranged V gamma families. Preliminary studies indicate that this approach can provide information about the presence of predominant T-cell clones within the sample and thus help to classify the lymph node lesion. With this technique we were able to confirm clonality in seven of 12 T-cell lymphomas in paraffin-embedded tissues.

Adult↗

PubMed1994

Circadian oscillations of a transcript encoding a germin-like protein that is associated with cell walls in young leaves of the long-day plant Sinapis alba L.

As part of an attempt to analyze rhythmic phenomena in the long-day plant Sinapis alba L. at the molecular level, we have searched for mRNAs whose concentration varies as a function of time of day. Differential screening of a cDNA library established from mRNAs expressed at the end of the daily light phase with probes representing transcripts expressed predominantly in the morning or evening has identified one major transcript. The cDNA, Saglp, encodes a predicted 22-kD protein with an N-terminal signal sequence. The protein shows homology to germin, a protein expressed in wheat embryos after onset of germination. The Saglp mRNA level undergoes circadian oscillations in light/dark cycles with maxima between 8 and 12 PM (zeitgeber time [zt]12-zt16) and minima around 8 PM (zt0). In plants grown from seed in constant light, transcript levels are constitutive. In constant light regular temperature shifts function as an alternative "zeitgeber" to initiate Saglp transcript oscillations. At the cellular level, Saglp transcripts are expressed in the epidermis and spongy parenchyma of young leaves, and in distinct regions of the epidermis and the cortex in stems and petioles. Strong signals are observed in these tissues around zt12, whereas little expression is found around zt20, suggesting that the underlying oscillatory mechanism(s) operate(s) synchronously in different plant organs. The SaGLP steady-state protein concentration remains constant over light/dark cycles. Immunogold labeling shows that the SaGLP protein is associated with primary cell walls.

Amino Acid Sequence↗

PubMed1994

Castleman's disease. Differences in follicular dendritic network in the hyaline vascular and plasma cell variants.

Twenty-seven cases of the hyaline vascular variant and 10 cases of the plasma cell variant of Castleman's disease were studied with the paraffin resistant monoclonal antibodies Ki-FDC1p and/or Ki-M4p against follicular dendritic cells. Studies with the monoclonal antibody Ki-M9, for the detection of sinus lining cells, were also performed on the available frozen tissue in four cases of the hyaline vascular variant. In nine of the 10 plasma cell variant cases, the predominant type of follicular dendritic cell network was similar to that seen in normal or reactive germinal centres. In contrast, the hyaline vascular variant demonstrated either an expanded, disrupted, follicular dendritic cell network (10 cases) or multiple tight collections of follicular dendritic cells (16 cases). Sinus lining cells were not detected in the four cases studied. The difference in the predominant type of dendritic meshwork is an additional distinguishing feature to separate the plasma cell and hyaline vascular variants of Castleman's disease. The patterns of dendritic network seen in the hyaline vascular type, together with the absence of sinus lining cells, appear to favour the hamartoma theory proposed for this variant.

Castleman Disease↗

PubMed1994

Magnetic activated cell sorting (MACS)--a new immunomagnetic method for megakaryocytic cell isolation: comparison of different separation techniques.

Megakaryocytes are difficult to isolate because of their fragility, their tendency to aggregate, and their varying sizes. For purification of cells at different stages of maturation and of different sizes (ploidy classes) we developed an immunomagnetic cell sorting method (MACS) to enrich the whole spectrum of the megakaryocytic cell lineage. The use of small magnetic beads coupled to various antibodies and labelling with fluorescent antibodies allowed direct analysis of enrichment and evaluation of the isolated fraction without further staining or detachment procedures. CD 61 (Y2/51), a monoclonal antibody directed against platelet glycoprotein IIIa, was employed to perform the separation procedure. An enrichment up to 47% of CD 61-positive cells with an average of 37% and a recovery rate of 37% was obtained by using the MACS technique. Pre-enrichment by Percoll density centrifugation, followed by MACS separation, resulted in an enrichment of 65% and a recovery rate of 67%. The relative amount of small megakaryocytic cells in only MACS-enriched cell populations, however, was higher than in Percoll/MACS fractions. As a parameter of vitality we tested cytokine secretion of the enriched megakaryocytes in reverse haemolytic plaque assays. Secretion of IL-1, IL-6, GM-CSF, and PDGF with and without stimulation by phorbol myristate acetate was demonstrable at the single cell level.

Bone Marrow Cells↗

PubMed1994

Helicobacter pylori gastritis and primary gastric non-Hodgkin's lymphomas.

AIMS: To evaluate further the relation between gastric malignant lymphoma of the mucosa associated lymphoid tissue (MALT) and Helicobacter pylori. METHODS: One hundred and sixty two surgical specimens of MALT lymphoma were retrospectively investigated to determine tumour type and inflammatory patterns. In 121 cases biopsy specimens obtained before surgery were available and stained with haematoxylin and eosin, periodic acid Schiff, Giemsa and Warthin-Starry stains. RESULTS: Residual lymphoid follicles were found less often in high grade malignant than in low grade malignant MALT lymphomas. Chronic active gastritis was shown within the mucosa at some distance from the tumours in 143 of 146 specimens. In all the cases for which biopsy specimens could be evaluated, colonisation of the mucosa by H pylori had occurred. Lymphoid follicles and lymphoid aggregates were detected in 82.7% of the antral, and in 85% of the body mucosa specimens. CONCLUSIONS: These data support the hypothesis that H pylori has an important role in the development of MALT lymphomas. Furthermore, the chronic inflammation preceding malignant transformation might enhance the probability of malignant transformation via chronic stimulation of the lymphoid tissue. This might in part indicate why MALT lymphomas occur most often in the stomach.

Adult↗

PubMed1994

Ki-S1 and proliferating cell nuclear antigen expression of bone marrow macrophages. Immunohistochemical and morphometric study including reactive (inflammatory) myelitis, secondary aplastic anemia, AIDS, myelodysplastic syndromes and primary (idiopathic) osteomyelofibrosis.

There is general agreement on the fact that bone marrow macrophages present a non-proliferating cell population. Using a sequential double-immunostaining technique, a morphometric analysis was performed on routinely processed bone marrow biopsies derived from 70 patients. The purpose of this study was, firstly, to determine the frequency of bone marrow macrophages in a variety of lesions and, secondly, to elucidate whether there is any proliferative activity detectable by immunohistochemical markers. Bone marrow pathology included reactive myelitis (RM), secondary aplastic anaemia (AP), AIDS-related myelopathy, primary (idiopathic) osteomyelofibrosis (OMF) and myelodysplastic syndromes (MDS). The monoclonal antibody PG-M1 which recognizes a formalin-resistant epitope on macrophages and PC10 raised against proliferating cell nuclear antigen (PCNA) were employed. For comparison with the PCNA-labelling index, the newly developed monoclonal antibody Ki-S1, which is associated with cell proliferation, was applied. In comparison with normal bone marrow, morphometric evaluation revealed a significant increase in macrophages in MDS, OMF, RM and especially in HIV-infected patients. Moreover, a positive immunostaining of single macrophages with PC10 was noted very infrequently. This rather inconspicuous PCNA labelling increased in AIDS. By contrast, Ki-S1 expression was found in none of the other pathologies studied. The prevalence of the macrophage population in certain disorders may have a multifactorial origin, such as inflammatory changes like intercurrent infections in AIDS and enhanced cell turnover in MDS as well as involvement of the complex pathomechanisms generating bone marrow fibrosis. In keeping with previous studies, the insignificant PCNA expression of macrophages should not be related to cell proliferation, but to unscheduled DNA strand repair which may be generated in the course of viral infection in AIDS.

Acquired Immunodeficiency Syndrome↗

PubMed1994

Evolution of fibro-osteosclerotic bone marrow lesions in primary (idiopathic) osteomyelofibrosis--a histomorphometric study on sequential trephine biopsies.

Evolution of fibro-osteosclerotic bone marrow lesions in the course of primary (idiopathic) osteomyelofibrosis (OMF) was studied in 36 patients (17 males, 19 females; median age 57 years) by morphometric evaluation of sequential trephine biopsies. The mean interval between first and terminal examination was 33 months (range 6 to 121 months). Two biopsies were performed in 31 and three and more in five patients. Morphometry consisted of a determination of argyrophilic (reticulin and collagen) fiber density, measured per area of hematopoiesis or marrow cellularity, and the calculation of the extent of trabecular bone tissue. In 13 of our 36 patients increase in reticulin and collagen deposits was only borderline to minimal during the observation period. On the other hand, in 23 of the 36 patients a slight to gross accumulation of reticulin and collagen fibers, partially associated with osteosclerotic changes was recognizable. No regression of fibrosis was encountered in our cohort of patients which included three cases with preceding low-dose busulfan therapy. Analysis of the different lengths of intervals between the first and the last biopsy and degree of fibrosis as well as osteosclerosis, suggested that alterations developed progressively, however, at an unpredictable and considerably varying rate. Thus our findings were not in keeping with several studies on smaller series of patients, which generally contested a progression of fibro-osteosclerotic lesions in OMF and additionally reported reversal of the pathology following chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗