Search PubMed⌕ Search

Biomedical subjects

K Hell

Publications and source records attributed to K Hell.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Antibiotic prophylaxis in appendectomy. Often neglected--but necessary!].

For several decades it has been proven that adequate antimicrobial prophylaxis is effective in reducing postoperative septic complications also in appendectomy. The rational for this approach--including laparoscopic procedures--is discussed and national and international recommendations for antibiotic prophylaxis in appendectomy are cited. Unfortunately, in spite of all the evidence, less than 50% of all appendectomies in 1996 in Germany had been carried out under antibiotic cover--with serious consequences for many patients and increased costs for prolonged hospital stay and treatment due to the higher incidence of infectious postoperative complications. Surgeons are encouraged not to neglect facts and benefits concerning the use of appropriate prophylactic antimicrobials in all appendectomies.

Antibiotic Prophylaxis↗
PubMed1997

Oxa1p mediates the export of the N- and C-termini of pCoxII from the mitochondrial matrix to the intermembrane space.

Oxa1p is a mitochondrial protein reported to be involved in the assembly of the cytochrome oxidase complex. In the absence of a functional Oxa1p, subunit II of the cytochrome oxidase accumulates as its precursor form (pCoxII). Using mitochondria isolated from a yeast strain bearing a temperature sensitive mutation in the Oxa1p, pet ts1402, we have analyzed the function of the Oxa1p protein. We demonstrate that the accumulation of pCoxII in the pet ts1402 mitochondria does not reflect a compromised Imp1p activity in this mutant. Furthermore, measurement of the membrane potential has shown it to be sufficient to support the export of CoxII from the matrix. Rather, we found that newly synthesized pCoxII accumulates in the matrix of the pet ts1402 mitochondria, because export across the inner membrane is inhibited in the pet ts1402 mitochondria. In conclusion, Oxa1p mediates the export of the N- and C-termini of the mitochondrially encoded subunit II of cytochrome oxidase from the matrix to the intermembrane space.

Biological Transport↗
PubMed1995

[Hodgkin cells are clonal B-cells in various stages of differentiation].

Hodgkin's disease, especially its biology and pathogenesis, has been under discussion for more than 160 years. Numerous investigations have focused on the nature and clonality of Hodgkin cells, but so far no definitive answer have been yielded by immunohistochemistry, Southern blotting and PCR. However, the use of single-cell PCR has now made it possible to answer the question of the derivation of Hodgkin cells. Using a micromanipulator, Hodgkin cells can be picked out of histological sections and B-cell specific gene rearrangements (VDJ) can be amplified. With this technique it has proved possible to demonstrate the B-cell derivation of Hodgkin cells and their clonality. Mutated immunoglobulin genes in lymphocyte-predominant Hodgkin's disease indicate a germinal center cell origin of Hodgkin cells of this type. These findings, however, do not exclude cases of Hodgkin's disease with Hodgkin cells with a T-cell genotype.

Antigens, CD↗
PubMed1995

Reactive versus neoplastic monocytoid B-cell proliferations. In situ hybridization study of immunoglobulin light chain mRNA.

To distinguish reactive versus neoplastic monocytoid B-cell (MBC) proliferations, the clonality of MBC was examined in paraffin-embedded tissues by in situ hybridization (ISH) of immunoglobulin (Ig) light chain messenger RNA (mRNA) with sensitive oligonucleotide probes in 26 cases. They included 13 cases of lymphadenitis with MBC reaction and 13 cases of nodal (n = 8) and extranodal (n = 5) monocytoid B-cell lymphoma (MBCL). Two cases represented a composite lymphoma showing a centroblastic-centrocytic and MBCL component. The clonality of MBC infiltrates could be demonstrated in 16 of 26 (61.5%) cases by immunostaining for Ig light chains and in all (100%) cases by ISH. Neoplastic MBC usually expressed a faint-to-moderate light chain restriction of mRNA, whereas some MBC (10% to 30% of total MBCL population) showed a strong positivity irrespective of plasmacytoid differentiation as indicated by Ig immunostaining (present in 9 of 13 cases). Reactive MBC expressed a faint kappa and lambda light-chain mRNA positivity. Five percent to 20% of total reactive MBC showed also a strong positivity for both Ig light chain mRNA, although only a minor part of these cells (7 of 13 cases) expressed polyclonal Ig by immunohistochemistry. These results indicate that (1) both reactive and neoplastic MBC can differentiate into plasma cells; and (2) a relatively high percentage of reactive and neoplastic MBC show a detectable mRNA transcription, but not a corresponding Ig synthesis. Either the Ig detection is not sensitive enough or these cells might be in an early differentiation phase, where the Ig production has not yet started.

Adolescent↗
PubMed1995

Combination of Hodgkin's disease and diffuse large cell lymphoma: an in situ hybridization study for immunoglobulin light chain messenger RNA.

It is not clear whether the rare combination of Hodgkin's diseases with non-Hodgkin lymphomas are true composite lymphomas or differentiation stages of one tumour cell clone. We used in situ hybridization and immunohistochemistry for the demonstration of immunoglobulin light chains in order to investigate the relationship between the two lymphoma components. In three cases of nodular lymphocyte predominance Hodgkin's disease combined with diffuse large B-cell lymphoma the Hodgkin cells, as well as the tumour cells in the diffuse large B-cell lymphoma, showed the same messenger RNA for one light chain. Thus, using in situ hybridization in nodular lymphocyte predominance Hodgkin's disease combined with diffuse large B-cell lymphoma in a small number of cases a possible genetic relationship between the two components could be shown. In nodular sclerosis combined with diffuse large B-cell lymphoma, in situ hybridization did not support a common clonal origin of both tumour parts. However, a unique clonal derivation cannot be excluded by the techniques applied.

Hodgkin Disease↗
PubMed1995

Hodgkin cells accumulate mRNA for bcl-2.

BACKGROUND: The bcl-2 oncogene is able to prevent cells from apoptosis. Overexpression of the bcl-2 protein seems to be important for the pathogenesis of follicular center cell lymphomas, in which both protein and mRNA usually show high levels. In addition, the expression of the Epstein-Barr virus-encoded late membrane protein up-regulates the bcl-2 protein in cell lines. The aim of the current study was to investigate the expression of the bcl-2 oncogene in Hodgkin's disease both at the protein and mRNA level in correlation with the expression of the late membrane protein. EXPERIMENTAL DESIGN: Thirteen cases of all histologic types of Hodgkin's disease, six cases of chronic nonspecific lymphadenitis, three tonsils with follicular hyperplasia, seven cases of follicular small cleaved cell lymphoma, and six cases of follicular large cell lymphoma, were analyzed. We designed a novel digoxigenin-labeled oligonucleotide probe complementary to bcl-2 mRNA for nonisotopic in situ hybridization. Bcl-2 oncoprotein and late membrane protein expression were determined by immunohistochemistry. The presence of the 14;18 translocation was analyzed by PCR for the major breakpoint region. RESULTS: The main finding was that, irrespective of subtype, the vast majority of Hodgkin cells express abundant bcl-2 mRNA. Oncoprotein expression, however, varied from case to case, with the highest prevalence in the nodular sclerosing subtype, and showed no strict correlation with the late membrane protein. In our case, no 14;18 translocation could be found in Hodgkin's disease. CONCLUSIONS: Hodgkin cells in all types of Hodgkin's disease demonstrated high levels of bcl-2 mRNA, while the bcl-2 protein expression was inhomogenous. In nodular lymphocyte predominant type, the bcl-2 mRNA and protein pattern is comparable to germinal center cells. This finding is a further argument for the germinal center cell origin of this type of Hodgkin's disease.

Base Sequence↗
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↗
PubMed1993

Demonstration of light chain mRNA in Hodgkin's disease.

The lineage of Hodgkin and Reed-Sternberg cells is still unclear. Detection of both immunoglobulin light chains in Hodgkin and Reed-Sternberg cells by immunohistochemistry is a well-known phenomenon. However, up to now, in situ hybridization techniques have failed to demonstrate light chain messenger(m) RNA in Hodgkin and Reed-Sternberg cells. In this investigation, we have analysed 26 cases of Hodgkin's disease (nodular lymphocyte predominant Hodgkin's disease, mixed cellularity, and nodular sclerosis type) using digoxigenin-labelled oligonucleotide probes for kappa and lambda light chains by in situ hybridization. In nearly half of the cases of nodular lymphocyte predominant Hodgkin's disease and in one case of mixed cellularity type, mRNA for only one light chain could be clearly demonstrated in the lymphocytic and histiocytic cells, Hodgkin, and Reed-Sternberg cells. These results support the idea that at least some cases of Hodgkin's disease are B-cell neoplasms.

Hodgkin Disease↗
PubMed1993

Expression of the proliferating cell nuclear antigen in the different types of Hodgkin's disease.

Thirty-eight cases of Hodgkin's disease (HD, lymphocyte-predominant, n = 10; nodular sclerosis, n = 10; mixed cellularity, n = 10; lymphocyte depletion, n = 8) were investigated with the antibody PC10 directed against the proliferating cell nuclear antigen (PCNA) with B- and T-cell markers using a double-staining technique in paraffin-embedded material. It could be shown that nearly all (95-97%) Hodgkin's and Reed-Sternberg (HRS) cells and their variants were PCNA-positive regardless of the type of HD. There was only a low number of PCNA-positive lymphocytes (2.8-3.4%) in all types mostly consisting of MT1-positive T lymphocytes. In contrast to the other types, lymphocyte-predominant type showed a relatively high percentage (5%) of Leu-7-positive lymphocytes. The high percentage of PCNA-positive HRS cells correlates with their malignant nature, and might be another example of dysregulated expression of PCNA.

Antigens, Differentiation↗
PubMed1992

[Which are the proliferating cells in Hodgkin's disease?].

This investigation characterizes the proliferating cells in Hodgkin's disease. We used the antibody PC 10 which reacts with the proliferating cell nuclear antigen (PCNA) and works on paraffin sections in combination with B- and T-cell markers in a double-staining technique. In all 38 cases of Hodgkin's disease (lymphocyte predominant type n = 10, nodular sclerosis type n = 10, mixed cellularity type n = 10, lymphocyte depletion type n = 8) a high percentage of the Hodgkin and Sternberg-Reed cells (95%-97%) expressed PCNA. There was no statistical significance between the different types. In contrast, only a small amount of the reactive lymphocytes (2.8%-3.4%) demonstrated positivity for PCNA in the four types of Hodgkin's disease. Nearly all of these lymphocytes were T-lymphocytes.

Antigens, CD↗
PubMed1992

[Bcl-2 in potentials precursors of nodular paragranuloma and its dedifferentiated variant (large cell B-lymphoma)].

We have investigated seven cases of large cell lymphomas (LCL) developing simultaneously or metachronously to nodular lymphocyte-predominant Hodgkin's disease (nodular paragranuloma, NP) for the presence of EBV and the chromosomal translocation t(14;18) by use of the polymerase chain reaction (PCR). The expression of the bcl-2 oncogene product in these cases and in five cases of progressive transformation of germinal centres as a potential precursor of NP was detected immunohistochemically with the monoclonal antibodies bcl-2-100 and bcl-2-124. All cases investigated were negative for EBV genomic material. The chromosomal translocation t(14;18) was also absent. Expression of the bcl-2 oncogene could be detected only in one case of nodular paragranuloma and in an unrelated case of LCL. Hence, LCL developing out of NP differ from other germinal center derived high-grade lymphomas.

Adult↗
PubMed1992

Diurnal variation in refraction after excimer laser photorefractive keratectomy.

Diurnal fluctuations in vision are common after radial keratotomy (RK), associated with a myopic change in refraction and keratometric power mostly in the morning. After photorefractive keratectomy (PRK), only a small percentage of patients report fluctuations of vision. We tested ten such patients who had undergone excimer laser PRK with regard to refraction, keratometry, and visual acuity 5 to 20 months after surgery. Patients were examined five times during one day from 8:00 a.m. to 8:00 p.m. Ten volunteers serving as a control group were examined following the same protocol. None of the patients showed an increase in minus spherical power of the manifest refraction between morning and evening. The change in manifest refraction from morning to evening was +0.3 D +/- 0.3 D, which was not significantly different from the control group. The change in refraction did not correlate with keratometric power, follow-up time of age of the patients.

Adult↗
PubMed1991

[Distribution of immunocompetent cells small intestine transplantation in rats].

Heterotopic small bowel transplantation was performed in allogeneic rats with and without cyclosporine. Syngeneic animals served as controls. Small bowel allografts, lymphoid tissues and small bowel of the host were investigated by immunohistochemistry using antibodies against T-cells and macrophages. During rejection, increasing numbers of macrophages infiltrated preferentially the deep layers of the small bowel wall, whereas only a slight T-cell infiltration was observed. No histological changes were noted in the organs of the host. Cyclosporine prevented lymphoid as well as macrophage infiltration of the transplant. Rejection monitoring of small bowel transplants is possible by investigation of macrophage infiltration in deep biopsies including the submucosa.

Animals↗