Design of parenteral synthetic dipeptides for clinical nutrition: in vitro and in vivo utilization.
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Animals↗
Biomedical subjects
M Hummel
Publications and source records attributed to M Hummel.
Cell kinetics, morphology, and molecular IgVH gene rearrangements in Hodgkin's disease.
The present study dealt with the question of whether any cellular kinetic patterns correlate with clonal rearrangement of the IgVH gene as revealed by polymerase chain reaction on DNA extracted from lymph nodes with classical Hodgkin's disease (HD) and/or from single CD30+ cells (Hodgkin [H] and Reed-Sternberg [RS] cells). In 15/4 cases with H-RS cells of B or Null phenotype, signs of such monoclonality could be detected (group I) but not in the others (group II). CD30+/H-RS cells in group I differed slightly but significantly from those in group II in that they a) exhibited a larger fraction of cells attaining the anaphase/telophase stage of mitosis, and b) produced relatively more mononucleated cells (H) at the expense of multinucleated (RS) cells. In addition, reactive lymphoid cell (CD30-) infiltrates were considerably less dense in group I that in group II. These findings suggest that the cytokinesis of H-RS cells in group I was moderately more efficient than in group II. However, signs of monoclonality were not associated with the normalization of the mitotic process, which also proved to be disturbed in group I.
Adolescent↗
MUC2 gene suppression in human colorectal carcinomas and their metastases: in vitro evidence of the modulatory role of DNA methylation.
The development of the majority of colorectal carcinomas is associated with a diminished expression of the intestinal mucin MUC2 in the tumor cells. The significance and the mechanism of this alteration are not yet known. We sought to determine the molecular basis of this tumor-associated change and to investigate the extent to which it might also relate to metastases. MUC2 gene expression was compared in normal (N), carcinomatous (T), and metastatic tissues (M) from nine patients by immunohistochemistry, in situ hybridization, and Northern blotting. Immunohistochemistry and in situ hybridization showed consistently lower amounts of the expressed protein and mRNA in T and in M than in N; quantitative analysis by Northern blotting confirmed that the differences between MUC2 mRNA expression between N, T, and M were significant, the expression in metastases being less than 5% of that in the normal colonic tissue. The influence of DNA methylation as a possible regulatory mechanism of MUC2 gene expression was tested after the 5' and 3'-regions flanking the first exon of MUC2 were recovered from a genomic DNA library and used as probes in Southern blot. The DNA was isolated from colon carcinoma cell lines expressing MUC2 strongly (LS174T) or moderately (T84) and from that which was nonexpressing (Colo 205), and it was digested with the methylation-sensitive enzyme HpaII. The Southern blot patterns indicated that the increased methylation in the promoter region was concomitant with the decrease of MUC2 mRNA expression. Methylation of the promoter region ligated into a reporter vector suppressed the expression of the luciferase reporter gene in the three investigated cell lines. Furthermore, the expression of MUC2 gene was enhanced by treating the MUC2-expressing colon carcinoma cells with 5-aza-2'-deoxycytidine, a methylation-inhibiting agent. To our knowledge this is the first report to show that: (a) MUC2 gene is strongly suppressed in liver and lymph node metastases of colorectal carcinomas, and (b) suppression of MUC2 gene in colon carcinoma cells in vitro is associated with methylation of the promoter region.
Base Sequence↗
[Surgical cure of stress urinary incontinence by a Richardson lateral bladder suspension. 134 cases].
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Adult↗
[Telomerase as a tumor marker?].
The maintenance of the length of chromosomes (telomeres) is the prerequisite of unlimited malignant growth of cells. In normal cells the telomeres will be shortened by each cell division finally leading to cell senescence. Unlimited growing cells possess an enzyme, the telomerase, which is able to maintain the length of the telomeres by de novo synthesis of the telomeric repeats. In consequence the telomerase is detectable in nearly all malignant tumours and cell lines. However, in addition to malignant cells some type of non-malignant cells such as germ cells, activated lymphocytes and basal epithelial cells contain significant amounts of telomerase activity. Therefore, the detection of telomerase activity by extractive procedures such as TRAP assay is not sufficient to determine malignant nature of tissue samples.
Biomarkers, Tumor↗
[Hodgkin's disease: a mystery is being solved].
The cell lineage derivation and type of proliferation (monoclonal versus polyclonal) of the atypical cells in Hodgkin's Disease (HD) has remained in question up until now. Immunophenotypic studies favoured a lymphoid origin. Molecular biological studies using DNA extracted from whole biopsy material provided inconsistent results, probably due to the rarity of the atypical cells in the affected tissue. Hence the molecular biological studies were extended to the analysis of isolated atypical cells. However, even these single cells studies yielded conflicting results. We therefore have improved the technique of single cell isolation from tissue sections and applied it to 25 cases of classical HD and 11 cases of lymphocyte predominant HD (LPHD). We investigated a total of 1,465 single atypical cells for rearranged Ig variable-region chain (V) genes. In all instances in which the single cell DNA lead to a PCR amplification product, these were found to contain identical rearranged V region genes. All of these V region gene sequences proved to be highly mutated. The coding capacity of the rearranged Ig genes was frequently disrupted in classical HD but rarely in LPHD. The V sequences of the latter histotype showed in addition intra-clonal diversity in the majority of patients whereas this was not seen in all but one case of classical HD. Additionally, in 10 to 20% of classical HD cases T-cell antigens and/or cytotoxic molecules could be demonstrated in the atypical cells. These results indicate that, a) the atypical cells of LPHD are a clonal population of neoplastic germinal centre B cells; b) the atypical cells from 80-90% of classical HD cases represent a clonal expansion of B cells which are related to germinal centre B cells or their progeny; and c) the atypical cells of 10-20% of classical HD may originate from T cells.
Antigens, CD↗
Molecular biology of Hodgkin's disease.
The mist surrounding the origin and genesis of HRS cells of classical HD is beginning to dissipate. Molecular biological studies of classical HD at the single cell level strongly suggest that the HRS cells in the majority of cases represent a monoclonal outgrowth of late germinal centre B cells that have lost their capacity to express IG through crippling mutations introduced during the germinal centre reaction. Because of the expression of T cell antigens and/or cytotoxic molecules, the HRS cells of a minority of classical HD cases appear to originate from T cells. Under physiological conditions, B cells that are unable to express IG are eliminated by apoptosis. In most B cell derived classical HD cases, the HRS cells have lost their IG gene coding capacity through mutation and should therefore die of apoptosis. Since this usually does not happen, blockade of the apoptotic pathway may be a major event in the pathogenesis of B cell related classical HD. It is tempting to assume that viruses such as EBV, as well as regulator genes that normally monitor the human genome for damaged DNA, such as TP53, might be involved in the postulated hindrance of the apoptotic pathway, leading to the genesis of classical HRS cells.
Chromosome Aberrations↗
Anaplastic large-cell lymphomas of T-cell and null-cell phenotype express cytotoxic molecules.
To further specify the cellular origin and nature of anaplastic large-cell lymphoma (ALCL) and its relationship to other lymphoid neoplasms, particularly Hodgkin's disease (HD), we investigated the presence of cytotoxic molecules in a large well-characterized series of these tumors. For expression of the cytotoxic molecules perforin and granzyme B, in situ hybridization (ISH) and immunohistology were used, respectively. Overall, 23 of 25 ALCLs of T/null phenotype and five (three mixed cellularity and two nodular sclerosis) of 57 HD cases showed the presence of perforin transcripts and/or granzyme B molecules in neoplastic cells. Polymerase chain reaction (PCR) analysis of ALCLs showed that most (10 of 11) cases of null-cell ALCL (null-ALCL) contained a clonal rearrangement of T-cell receptor beta-chain genes, as did T-cell ALCL (T-ALCL; 9 of 10 cases). However, both cytotoxic molecules and clonally rearranged T-cell receptor beta-chain genes were absent in seven of seven and eight of nine cases of B-cell ALCL (B-ALCL), respectively. These data show that all or nearly all T-ALCLs, irrespective of the clinical subform or the lack of T-cell-associated molecules, are derived from activated cytotoxic T cells. The same appears to be true for the neoplastic cells of rare HD cases. These findings indicate that T-ALCLs are different from B-ALCLs and the majority of HD cases, and suggest that some HD cases, especially those with T-cell antigen-positive tumor cells, may be closely related to T-ALCL, at least in terms of cellular origin.
Biomarkers↗
Molecular characterization of AKAP149, a novel A kinase anchor protein with a KH domain.
The cytosolic cAMP activates in eukaryotic cells several isoforms of cAMP-dependent protein kinase (PKAs) involved in signal transduction. The effects of individual PKA isoforms are determined by their cellular localisation, specified through binding to distinct A Kinase Anchor Proteins (AKAPs). A new member of the AKAP family, a membrane-anchored 903 amino acid long protein, designated AKAP149, is characterized in the present work. It is a putative splicing variant of S-AKAP84 with the important new feature of a RNA-binding motif (KH domain). This domain together with the known characteristics of AKAPs suggests the involvement of AKAP149 in the phosphorylation-dependent regulation of RNA-processing.
A Kinase Anchor Proteins↗
Expression of Epstein-Barr virus-gene products in Burkitt's lymphoma in Northeast Brazil.
The Epstein-Barr Virus (EBV) is consistently found in tumor cells of Burkitt's lymphoma (BL) endemic in central Africa and malaria is considered a pathogenic cofactor. In contrast, fewer than 20% of BL cases occurring in Western countries are EBV-associated. We have investigated 54 BL cases from Bahia, a tropical region of Northeast Brazil, for expression of EBV gene products by in situ hybridization and immunohistology and performed typing of the EBV by polymerase chain reaction. Ten pediatric BL cases from Germany served as controls. New cases of malaria were not observed in the period and area of our study. Small nuclear EBV encoded transcripts, EBER, were found in tumor cells of 47 of 54 Brazilian cases (87%) but in only 2 of 10 German cases (20%). Type I latency of the EBV infection with absence of EBV-encoded proteins LMP1 and EBNA2 was found in 45 of 47 of the EBER-positive Brazilian cases. In two cases, occasional LMP1-containing tumor cells were found in the neighborhood of small Schistosoma mansoni granulomas and scars. BHLF1 transcripts associated with lytic EBV infection could be detected in few cells in 3 of the 40 EBER-positive Brazilian cases investigated. EBV type A was found in the majority of Brazilian BL cases (20 of 30 A-type, 7 of 30 B-type, and 3 of 30 not amplifiable). Our results indicate that the association of Bahian BL with EBV, but not the regional prevalence of malaria, is similar to endemic African BL. In two cases, type II latency was found in association with schistosomiasis, suggesting a role of this parasitosis in the induction of an EBV expression pattern that is unusual for BL. Because chronic schistosomiasis is associated with elevated Th2 cytokine expression resulting in reduced cell-mediated cytotoxicity, it seems possible that altered local immunity is responsible for this peculiar phenotype.
Adolescent↗
Low frequency of p53 gene mutation and protein expression in mucinous colorectal carcinomas.
Immunohistochemical data indicate that the frequency of p53 protein overexpression is consistently lower in the mucinous than in the non-mucinous carcinomas of the breast, ovary, pancreas and colon. This peculiar immunohistochemical behavior of the mucinous phenotype could be due to the effect of large amounts of mucus on the staining or to an actual mutation frequency difference between mucinous and non-mucinous carcinomas. This question was investigated on a group of mucinous colorectal carcinomas. DNA was extracted from paraffin sections of 16 human mucinous colorectal carcinomas and the mutation frequency was determined by sequencing of p53 exons amplified in PCR. The expression of p53 protein was determined with the avidin-biotin complex-peroxidase staining procedure and CM-1 antiserum. Twenty-five percent of the tumors, exhibited p53 protein overexpression and in 31% a mutation was detected. Concordance between the two techniques was found in 69% of tumors. Overexpression without mutation was observed in 12% and mutation without overexpression in 19%. G:C --> A:T transitions represented the most frequent lesion (80%), as previously observed in non-mucinous colorectal carcinomas. These data indicate that the mutation pattern in the p53 gene is similar in mucinous and non-mucinous colorectal carcinomas. The low frequency of p53 overexpression in the mucinous phenotype is not due to a mucus effect on the staining but is related to the low mutation frequency of p53 gene. These results lead to the hypothesis that in contrast to the nonmucinous tumors the development of the majority of colonic carcinomas with the mucinous phenotype may be independent from p53 mutations.
Adenocarcinoma, Mucinous↗
Monokine expression in Langerhans' cell histiocytosis and sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease)
Langerhans' cell histiocytosis (LCH) is a clonal proliferation of Langerhans cells (LC) showing histologically an abundant reactive infiltrate composed of macrophages and lymphocytes, as well as eosinophilic and neutrophilic granulocytes. Rosai-Dorfman disease (RDD) shows a sinusoidal accumulation of large histiocytic cells with an immunophenotype similar to LC of LCH. The histological picture of LCH is reminiscent of an inflammatory disorder and LC may produce cytokines and are influenced by these soluble factors. This study set out to establish the monokine expression pattern in LCH in comparison with those of RDD; dermatopathic lymphadenopathy, which also shows a proliferation of S100-positive dendritic cells; and LC in normal skin specimens. Isotopic in situ hybridization was used for the detection of transcripts of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-1 beta, in some cases combined with immunohistology for the S100 protein or CD68. In all 11 tissue samples from eight patients, LC of LCH expressed TNF-alpha; in two cases IL-1 beta transcripts were additionally noted in some LC, whereas IL-6 was found in reactive cells. Large histiocytic cells of RDD expressed all three monokines, whereas minimal or no expression of these cytokines could be detected in interdigitating reticulum cells in dermatopathic lymphadenopathy. In two out of five normal skin samples, only TNF-alpha specific signals were observed in LC. These data suggest that histologically different lesions of the histiocytic/dendritic cell system display distinct cytokine profiles. The expression of monokines, which have been demonstrated to influence various functions of epidermal LC, may play a role in the pathogenesis of LCH. Systemic symptoms in RDD may be related to enhanced production of monokines in these lesions.
Child↗
Relation between cellular and humoral immunity to islet cell antigens in type 1 diabetes.
The autoimmune disease insulin-dependent diabetes is thought to result from T-cell mediated destruction of pancreatic beta cells. We analysed the relation between humoral and cellular immunity to multiple islet cell antigens, including human insulin, glutamate decarboxylase GAD65, tyrosine phosphatase (ICA512/IA2), human pancreas and RIN cells in 28 patients with newly diagnosed type 1 diabetes and 9 antibody-positive (Ab+) relatives at high risk for type 1 diabetes. Of newly diagnosed patients, all showed reactivity to at least one recombinant islet cell antigen, by elevated cellular or humoral (or both) immune responses. Fifty-seven percent of patients and relatives showed T-cell reactivity to more than one islet cell antigen and 68% revealed humoral immunity to more than one islet cell antigen. Increased T-cell response to one single islet cell antigen was observed in 32% and positive antibody response in 25% of diabetic patients and relatives. Further-more, we found that T-cell reactivity to GAD was associated with T-cell reactivity to RIN cells, whereas reactivity to ICA512 and insulin was not associated with any other T-cell response. Likewise, antibody response to ICA512/IA2 correlated with antibodies to human pancreas (ICA), whereas antibody response to GAD or insulin was not related to any other antibody response. No positive or inverse correlation, however, was detected between T cell and humoral immunity, except for a positive association of antibodies and T-cell reactivity to insulin. Our data suggest that both humoral and cellular immune reactivity to multiple islet cell antigens are present in patients with newly diagnosed type 1 diabetes and in high risk relatives, but the two immune responses are individually activated.
Adolescent↗
Intestinal T-cell lymphoma: a reassessment of cytomorphological and phenotypic features in relation to patterns of small bowel remodelling.
Intestinal T-cell lymphoma (ITCL) is an uncommon entity among primary gastrointestinal lymphomas. In this study we evaluated tumours from 20 patients presenting with (n = 8) or without (n = 12) a history of coeliac disease (CD). Neoplastic lesions were composed of predominantly small (n = 4), small-to-medium (n = 2), medium/mixed-to-large (n = 7) or large and anaplastic (n = 7) cells. Different patterns of tumour growth and remodelling of the small bowel wall were observed. Pattern a (n = 4) was characterized by an intramucosal spread of small tumour cells with a small growth fraction. This pattern resembles mucosal inflammation in CD. In pattern b (n = 2), ulcerated solitary or multiple tumours composed of small to medium-sized cells were observed. The adjacent or distant mucosa showed a nearly normal architecture. In pattern c (n = 7), ulcerated lesions were composed of medium-sized to large cells. Mucosal flattening occurred in all segments infiltrated by lymphoma. In pattern d (n = 7), bowel remodelling was observed along the small intestine even at sites not affected by lymphoma. The main neoplastic lesions were composed of pleomorphic large or anaplastic cells frequently expressing the CD30 molecule. Intramucosal spread of a small epitheliotropic T-cell population was observed in the vicinity or even at distant segments of the small bowel. The demonstration of clonal rearrangements of T-cell receptor genes helped to trace widespread occurrence of this small intraepithelial neoplastic component. We suggest that different features of tumour cells such as the expression of activation antigens may contribute to the remodelling of small bowel mucosa. The addition of immunophenotyping data to macroscopic and microscopic features of specimens provided evidence that this uncommon lymphoma exhibits a spectrum in cytological composition and growth patterns. However, despite the considerable heterogeneity of the cases analysed, most of them shared a characteristic immunohistochemical profile (CD3+, CD8+/-, CD103+), further substantiating the view that ITCL is the neoplastic equivalent of an intraepithelial T-cell subset of the small intestine. This phenotype and the intraepithelial accumulation of lymphoma cells observed in the surviving mucosa are clues to the diagnosis of this clinicopathological lymphoma entity characterized by a broad range of morphological expressions.
Adult↗
Decreased expression of ventricular angiotensin receptor type 1 mRNA after human heart transplantation.
Myocardial angiotensin receptors of type 1 (AT1) are downregulated at the protein and mRNA levels in human heart failure. No data are available for the transplanted human heart, which frequently exhibits functional alterations. The aim of the present study was the quantitation of ventricular AT1 mRNA content in endomyocardial biopsies from patients after heart transplantation. For the determination of AT1 mRNA we used a novel quantitative reverse transcription polymerase chain reaction with low variance (6%) based on an internal AT1 cRNA standard, liquid-phase hybridization of polymerase chain reaction products in microtiter plates, and quantitation by enzyme-linked immunosorbent assay. Right ventricular biopsies from 16 patients after heart transplantation (left ventricular ejection fraction 67 +/- 7%) were compared with 12 patients with normal cardiac function (left ventricular ejection fraction 62 +/- 5%). A 46% lower AT1 mRNA content was found in biopsies from the 16 patients after heart transplantation than in the 12 controls (heart transplantation, 200 +/- 25 AT1 mRNA copies/ng RNA; controls, 368 +/- 50; P < 0.01). When AT1 mRNA content was related to the stably expressed GAPDH mRNA, a 49% decrease was detected (AT1/GAPDH: patients, 2.4 +/- 0.25; controls, 4.7 +/- 0.6; P < 0.006). No association between the extent of AT1 downregulation and clinical or hemodynamic variables was detected. In the human heart ventricular AT1 is downregulated after orthotopic heart transplantation. The decrease in AT1 mRNA is not associated with altered systolic function. This may partially reflect a loss of autonomic nerves and thus altered nervous control of the heart.
Adolescent↗
Heart transplantation: a single-center experience.
BACKGROUND: The success of heart transplantation led to the extension of the criteria for both recipients and donors. The aim of the study was to evaluate the experience with this therapeutic approach for end-stage heart failure at a single center. METHODS: Between April 1986 and January 1996, 1,413 patients were accepted as candidates for heart transplantation. Ventricular assist devices were used as a bridge to transplantation in 173 patients (biventricular assist device in 141 patients and left ventricular assist device in 32 patients). The longest duration of support was 572 days (average, 46 days). RESULTS: Of the 1,413 patients, 891 underwent heart transplantation (65 children/adolescents and 826 adults; 522 (36%) patients died awaiting a donor heart. The average time spent on the waiting list was 107 days. The average recipient age was 44 years, and the age of donors was extended up to 69 years. Eighty-three patients with ventricular assist devices (48%) subsequently underwent heart transplantation. Twenty-five patients (2.7%) underwent retransplantation. The 30-day mortality rate was 14%, and the overall actual survival at 1, 5, and 10 years was 80%, 59%, and 50%, respectively. Ninety-four percent of patients were in New York Heart Association functional class I or II at 1 year, and 44% returned to work after transplantation. CONCLUSIONS: Despite the broadening of the selection criteria for both recipients and donors, heart transplantation remains an effective treatment for end-stage heart failure. Nevertheless, this therapeutic approach is severely limited by a considerable disparity between the need and availability of donor organs.
Adolescent↗
Ig rearrangements in isolated Reed-Sternberg cells: conclusions from four different studies.
The cellular origin and the type of proliferation of the Hodgkin and Reed-Sternberg (HRS) cells, the malignant cells of Hodgkin's disease (HD), is an issue of constant debate. Immunohistochemical and molecularbiological studies of different research groups revealed contradictory results among the different groups ranging from a complete absence to a frequent presence of B-cell or T-cell characteristic features in the HRS cells. The determination of their clonality by cytogenetic means produced no conclusive results. To unequivocally clarify these questions we and others isolated single HRS cells and amplified their immunoglobulin (Ig) rearrangements. Most groups found Ig rearrangements within the HRS cells pointing to a B-cell nature of these HD cases. Individual IgH rearrangements were found in a proportion of the HD cases whereas most cases harbor monoclonal HRS cells with or without additional polyclonal rearranged HRS cells. Further studies are needed to clarify whether the differences among the different groups are caused by the selection of the HD cases used for investigation.
Gene Rearrangement↗
Epstein-Barr virus in tumours.
The Epstein-Barr virus (EBV) is the best characterized human virus known to infect most people all over the world. In most cases, primary infection with EBV is asymptomatic and the virus persists life-long without causing any disease. The availability of sensitive detection methods, however has led to the identification of a wide array of EBV-associated disease entities. Although nearly 9000 publications have been written since the first description of this virus in 1964, many questions concerning its function and infection patterns remain unanswered. The direct involvement of EBV in the pathogenesis of a disease has only been established for infectious mononucleosis and lymphoproliferative disorders in the setting of congenital or acquired immunodeficiency. Extensive investigations on the role of EBV infection in the pathogenesis of all other EBV-associated lymphoid and epithelial proliferations have led to the conclusion that EBV is not the primary causative agent but it can promote tumour development. Since the early steps in neoplastic development are difficult to assess, further studies are required to clarify the precise role of EBV infection. Furthermore, the clinical significance of the presence of EBV in neoplasia is largely unknown.
Acquired Immunodeficiency Syndrome↗