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Biomedical subjects

H Stein

Publications and source records attributed to H Stein.

At least 109 records · Page 6Linked to original sources
PubMed2000

Telomerase expression in uveal melanoma.

BACKGROUND/AIMS: Accumulating evidence indicates that telomerase activity is repressed in normal human somatic cells but reactivated in cancers and immortal cells, suggesting that activation of telomerase activity has a role in carcinogenesis and immortalisation. To date, telomerase in uveal melanoma and, whether, it may have a role in the development or progression of these tumours has not been described. The expression patterns and the activity of telomerase were investigated in 14 uveal melanoma and these results were correlated with histological and immunohistological features of these tumours. METHODS: A modified PCR based telomeric repeat amplification protocol (TRAP) assay was used to demonstrate telomerase activity in 14 uveal melanomas. In addition, in situ hybridisation was used to demonstrate the expression pattern of the telomerase RNA component (hTR) at the single cell level in eight of these globes. RESULTS: The TRAP assay revealed moderate telomerase activity in all uveal melanomas examined. In situ hybridisation visualised a moderate to high upregulation of hTR in the melanoma cells but not in the admixed reactive cells. There was no correlation among tumour location, cell type, or growth fraction and the amount of telomerase activity. In addition, the cells of the germinative zone of the lens demonstrated a strong hTR expression. CONCLUSION: Telomerase activity is upregulated in uveal melanomas. The expression of hTR was located to the tumour cells and not the reactive tumour infiltrating cells. Strong telomerase expression was also demonstrated in cells of the germinative zone of the lens.

Adult↗
PubMed2000

Detection of c-kit mutation Asp 816 to Val in microdissected bone marrow infiltrates in a case of systemic mastocytosis associated with chronic myelomonocytic leukaemia.

BACKGROUND/AIMS: The occurrence of myeloid leukaemia in patients with systemic mastocytosis is a well recognised phenomenon. However, the pathophysiological basis of such a coevolution has not been clarified. Recent data have shown that the c-kit mutation Asp 816 to Val is detectable in neoplastic mast cells in most patients with systemic mastocytosis, including those who have associated haematological disorders. The aim of this study was to study clonal disease evolution by analysing bone marrow cells from a patient with systemic mastocytosis and associated chronic myelomonocytic leukaemia (CMML) for the presence of this mutation. METHODS: The DNA of microdissected bone marrow cells from a patient with systemic mastocytosis and associated CMML was analysed for the presence of the c-kit mutation Asp 816 to Val by means of HinfI digestion and direct sequencing of semi-nested polymerase chain reaction (PCR) products. RESULTS: The two neoplasms could easily be identified and discriminated in paraffin wax embedded bone marrow sections by tryptase and chloroacetate esterase staining. A total number of 10 tryptase positive systemic mastocytosis infiltrates and 10 tryptase negative CMML infiltrates were removed by microdissection. As assessed by HinfI digestion and direct sequencing of semi-nested PCR products, the c-kit mutation Asp 816 to Val was detected in five of seven systemic mastocytosis infiltrates and four of six CMML infiltrates. By contrast, no c-kit mutation Asp 816 to Val was found in bone marrow infiltrates in patients with CMML without associated systemic mastocytosis (n = 20). CONCLUSION: These data support a monoclonal evolution of systemic mastocytosis and concurrent CMML in the patient studied.

Aged↗
PubMed2000

Refractory sprue syndrome with clonal intraepithelial lymphocytes evolving into overt enteropathy-type intestinal T-cell lymphoma.

INTRODUCTION: Recently, patients with refractory sprue have been shown to contain a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes in their intestine. Whether this signifies early enteropathy-type intestinal T-cell lymphoma (EITCL) or a reactive condition is not clear. We report on a patient presenting with the findings of refractory sprue who subsequently developed overt EITCL. MATERIAL AND METHODS: Duodenal biopsies from 1997 (refractory sprue) and duodenal and jejunal biopsies from 1998 (intestinal T-cell lymphoma) were compared by immunohistochemistry and PCR for the detection of T-cell receptor (TCR)-gamma gene rearrangements. Clonal PCR products were sequenced. RESULTS: The duodenal biopsies from both 1997 and 1998 and the jejunal tumor biopsy showed villus atrophy and an increase of intraepithelial lymphocytes with an abnormal immunophenotype (CD3+, CD4-, CD8- and TCR-beta-). In all duodenal specimens including the one from 1997, and the jenunal tumor biopsy, an identical clonal amplificate was detected by enzymatic amplification of the TCR-gamma gene. CONCLUSION: These data suggest that refractory sprue containing a clonal proliferation of phenotypically abnormal intraepithelial lymphocytes may represent an early manifestation of EITCL. The detection of immunohistochemical negativity for several antigens normally found on intraepithelial lymphocytes such as CD8 or the TCR-beta chain in combination with clonal T-cell populations by PCR may be helpful in identifying refractory sprue with a malignant transformation.

CD3 Complex↗
PubMed2000

Salvage therapy for relapsed mediastinal B-cell lymphoma with allogeneic HLA-identical related donor bone marrow transplantation, donor lymphocyte infusion and IDEC-C2B8.

Primary B-cell lymphoma of the mediastinum is an aggressive non-Hodgkin's lymphoma with distinct clinicopathologic features. Response rates are between 60-80% following intensive chemotherapy regimens. Poor responders or patients with an early relapse usually do not achieve a prolonged second remission with conventional salvage therapy protocols and therefore qualify for intensive or experimental approaches. Here we describe two patients of same age, gender and stage with primary mediastinal B-cell lymphoma and an early relapse after the first courses of combination chemotherapy and irradiation of the mediastinum. One patient relapsed after a salvage therapy with allogeneic donor-related bone marrow transplantation and donor lymphocyte infusion but responded again with a continuing good partial remission after infusion of the chimeric anti-CD20 antibody IDEC-C2B8. For the other patient an allogeneic bone marrow transplantation was not possible. He finally failed to respond to salvage therapy with IDEC-C2B8 and died of progressive disease. The anti-CD20 antibody IDEC-C2B8 induced a partial remission in a patient with primary mediastinal B-cell lymphoma refractory to other therapeutic approaches, including allogeneic bone marrow transplanatation (alloBMT), donor lymphocyte infusion (DLI) and irradiation. The role of IDEC-C2B8 as a component of salvage regimens appears to be worthy for further evaluation in high-risk patients with primary mediastinal B-cell lymphoma

Adolescent↗
PubMed2000

Lives through time: an ideographic approach to the study of resilience.

The authors describe and illustrate an ideographic method for the study of resilience. The method assumes that resilience is an unfolding and dynamic process in which the individual and the social environment interact to produce a life course over time. Using retrospective and prospective data, the authors present a case study of a profoundly troubled boy, first seen as a preschooler and then followed up in early adulthood with a battery of clinical interviews. The methodology presented provides a way to study resilience as a dynamic process and to reveal and make sense of counterintuitive findings. In contrast to historical or epidemiological methods, the approach also permits exploration of the role of intrapsychic processes in facilitating change.

Adaptation, Psychological↗
PubMed2000

[Monocytic B-cells represent a new cell population that is mainly recruited from unmutated polyconal naive B-cells].

Monocytoid B-cells appear as a distinct B-cell population in a number of lymphadenopathies but above all in Piringer's lymphadenopathy. Up until now, their assignment to a recognised B-cell subpopulation has not been conclusively achieved. Immunohistological studies have shown characteristics in common with the tumour cells of hairy cell leukemia and also with so-called splenic marginal zone cells. In order to unequivocally clarify their B-cell differentiation stage we have isolated single monocytoid B-cells from immunostained frozen sections and have analysed their immunoglobulin chain gene rearrangements. In addition we have studied the Ig-expression of monocytoid B-cells at both the RNA and protein levels.

B-Lymphocytes↗
PubMed2000

Laparoscopic cardiomyotomy in the treatment of esophageal achalasia.

Tu evaluate the usefulness of the laparoscopic approach as the standard procedure in the surgical treatment of achalasia. Among different competing options of the treatment of esophageal achalasia, extramucosal myotomy of the lower esophageal sphincter--usually combined with anterior fundoplasty--is the most effective but also the most invasive approach. Minimally invasive performance of this operation reduces invasivity and should make the operative treatment a more attractive alternative to other procedures, such as pneumatic dilatation or botox injection. From 1991 till 1997, 27 patients underwent laparoscopic Heller Dor operation (16 males, 11 females, mean age 37 years). Diagnosis was established in all of them by an esophagogram and esophageal manometry. The main symptom was dysphagia in all of the patients. No mortality was observed in this series. There were no conversions to laparotomy. The single intraoperative complication was one case of iatrogenic mucosal laceration. Post operative complications were found in one case of wound infection, and two cases of pneumomedistinum. After a mean follow-up of 33 months (3-77), all patients are without dysphagia and without pathological gastroesophageal reflux. The mean value of residual LES pressure could be reduced from 21 +/- 6.4 mmHg to 7.44 +/- 2.7 mmHg. Laparoscopic cardiomyotomy is at lesat as safe, in terms of morbidity and mortality, as open surgery and similarily effective in alleviating dysphagia. Short hospitalisation and convalascent periods have provided an attractive alternative to repeated dilations for many patients.

Adolescent↗
PubMed1999

Frequent expression of the B-cell-specific activator protein in Reed-Sternberg cells of classical Hodgkin's disease provides further evidence for its B-cell origin.

The neoplastic cells of classical Hodgkin's disease (cHD), ie, Hodgkin and Reed-Sternberg cells (HRS cells), contain clonally rearranged Ig genes, but are dissimilar to normal B cells in that they mostly do not display B-cell antigens such as CD20 or CD19. The transcription factor B-cell-specific activator protein (BSAP) influences numerous B-cell functions such as B-cell antigen expression, Ig expression, and class switch. We analyzed the expression of BSAP in cHD and control tissues by isotopic in situ hybridization and immunohistochemistry to determine whether BSAP is expressed in HRS cells and, if so, whether it may be involved in the genesis of the abnormal phenotype of these cells. Both in normal lymphoid tissue and non-Hodgkin lymphomas, BSAP transcripts and protein were almost exclusively found in B cells and B-cell lymphomas (40 cases), but were absent from the tumor cells of T-cell neoplasms (41 cases), including 19 cases of anaplastic large cell lymphoma of T- and null-cell type. Among cHD, variable numbers of HRS cells exhibited BSAP transcripts (22 of 25 cases) and protein (28 of 31 cases). Our findings show that BSAP is sufficiently specific to serve as B-cell marker. BSAP expression in HRS cells provides further strong evidence for a frequent B-cell origin of cHD and helps distinguish this disease from anaplastic large cell lymphoma of T- and null-cell type. Because BSAP is much more frequently expressed in HRS cells than the conventional B-cell antigens, the abnormal immunophenotype of HRS cells with frequent absence of B-cell antigens does not appear to be due to absent BSAP expression.

B-Lymphocytes↗
PubMed1999

Overexpression of I kappa B alpha without inhibition of NF-kappaB activity and mutations in the I kappa B alpha gene in Reed-Sternberg cells.

The transcription factor NF kappa B (NF-kappaB) mediates the expression of numerous genes involved in diverse functions such as inflammation, immune response, apoptosis, and cell proliferation. We recently identified constitutive activation of NF-kappaB (p50/p65) as a common feature of Hodgkin/Reed-Sternberg (HRS) cells preventing these cells from undergoing apoptosis and triggering proliferation. To examine possible alterations in the NF-kappaB/IkappaB system, which might be responsible for constitutive NF-kappaB activity, we have analyzed the inhibitor I kappa B alpha (IkappaBalpha) in primary and cultured HRS cells on protein, mRNA, and genomic levels. In lymph node biopsy samples from Hodgkin's disease patients, IkappaBalpha mRNA proved to be strongly overexpressed in the HRS cells. In 2 cell lines (L428 and KM-H2), we detected mutations in the IkappaBalpha gene, resulting in C-terminally truncated proteins, which are presumably not able to inhibit NF-kappaB-DNA binding activity. Furthermore, an analysis of the IkappaBalpha gene in single HRS cells micromanipulated from frozen tissue sections showed a monoallelic mutation in 1 of 10 patients coding for a comparable C-terminally truncated IkappaBalpha protein. We suggest that the observed IkappaBalpha mutations contribute to constitutive NF-kappaB activity in cultured and primary HRS cells and are therefore involved in the pathogenesis of these Hodgkin's disease (HD) patients. The demonstrated constitutive overexpression of IkappaBalpha in HRS cells evidences a deregulation of the NF-kappaB/IkappaB system also in the remaining cases, probably due to defects in other members of the IkappaB family.

Base Sequence↗
PubMed1999

Monocytoid B cells are distinct from splenic marginal zone cells and commonly derive from unmutated naive B cells and less frequently from postgerminal center B cells by polyclonal transformation.

Monocytoid B cells represent a morphologically conspicuous B-cell population that constantly occurs in Toxoplasma gondii-induced Piringer's lymphadenopathy. Although widely believed to be closely related to splenic marginal zone B cells, neither this relationship, nor the B-cell differentiation stage of monocytoid B cells, nor their cellular precursors have been established. We have therefore examined monocytoid B cells for their expression of B-cell differentiation markers and the Ig isotypes at the RNA and protein level as well as for rearranged Ig heavy chain (H) genes and somatic mutations within the variable (V) region. The results obtained were compared with the corresponding features of other B-cell populations. The monocytoid B cells displayed immunophenotypical differences to all other B-cell populations. IgM and IgD expression was absent from most monocytoid B cells at the RNA and protein levels. Unrelated (polyclonal) Ig rearrangements were found in 85 of the 95 cells studied. Seventy-four percent of the rearranged VH genes were devoid of somatic mutations, whereas the remaining 26% carried a low number of somatic mutations. The majority of these showed no significant signs of antigen selection. This finding in conjunction with the predominantly unrelated Ig gene rearrangements indicates that most monocytoid B cells arise not by clonal proliferation but by transformation of polyclonal B cells. The B cells undergoing a monocytoid B-cell transformation are in the majority (74%) naive B cells, and only a minority are (26%) non-antigen-selected postgerminal center B cells. Thus, our data show that monocytoid B cells represent a distinct B-cell subpopulation.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1999

Hodgkin/Reed-Sternberg cells induce fibroblasts to secrete eotaxin, a potent chemoattractant for T cells and eosinophils.

Hodgkin's disease is histopathologically characterized by the relative scarcity of neoplastic Hodgkin and Reed-Sternberg cells and for yet unknown reasons by an abundant reactive background of T lymphocytes and often eosinophils. Eotaxin is a CC-chemokine attracting eosinophils and T helper 2 (Th2) cells in allergic inflammation. We now report that eotaxin is strongly expressed in fibroblasts of Hodgkin's disease tissues, whereas Hodgkin/Reed-Sternberg cells do not express this chemokine. In tissue culture, Hodgkin's disease tumor cells induce eotaxin expression in cocultured dermal fibroblasts in a concentration leading to a specific chemotactic response of a Th2 cell clone. Production of tumor necrosis factor-alpha (TNF-alpha) by Hodgkin/Reed-Sternberg cells appears to be responsible for this induction, because blocking of TNF-alpha by neutralizing antibodies prevented fibroblast eotaxin expression. Our data suggest that eotaxin is involved in the pathobiology of Hodgkin's disease by contributing to eosinophil and T-lymphocyte recruitment.

Cells, Cultured↗
PubMed1999

Three new types of Apaf-1 in mammalian cells.

Apaf-1, the human C. elegans Ced-4 homologue, plays a crucial role in mitochondrial mediated apoptosis. To determine whether a mutant Apaf-1 is involved in the pathogenesis of malignant lymphomas, we performed sequence analysis of its transcriptional gene product. Therefore, cDNAs coding for Apaf-1 were examined in six lymphoma derived cell lines, in three non-lymphoid tumor cell lines, as well as in peripheral blood lymphocytes and in tissue from heart, kidney, and liver by RT-PCR. These studies did not disclose the expected tumor related alterations but led instead to the identification of three novel forms of Apaf-1. These forms vary in length, but contain all functional domains formerly characterized in the Apaf-1 protein. The results indicate that the previously published sequence is not the Apaf-1 form most widely expressed.

Amino Acid Sequence↗
PubMed1999

Injection of encapsulated cells producing an ifosfamide-activating cytochrome P450 for targeted chemotherapy to pancreatic tumors.

The prognosis of pancreatic cancer is poor, and current medical treatment is mostly ineffective. The aim of this study was to design a new treatment modality in an animal model system. We describe here a novel treatment strategy employing a mouse model system for pancreatic carcinoma. Embryonal kidney epithelial cells were genetically modified to express the cytochrome P450 subenzyme 2B1 under the control of a cytomegalovirus (CMV) immediate early promoter. This CYP2B1 gene converts ifosfamide to its active cytotoxic compounds, phosphoramide mustard, which alkylates DNA, and acrolein, which alkylates proteins. The cells were then encapsulated in a cellulose sulphate formulation and implanted into preestablished tumors derived from a human pancreatic tumor cell line. Intraperitoneal administration of low-dose ifosfamide to tumor bearing mice that received the encapsulated cells results in partial or even complete tumor ablation. Such an in situ chemotherapy strategy utilizing genetically modified cells in an immunoprotected environment may prove useful for solid tumor therapy in man.

Animals↗
PubMed1999

[Primary cerebral highly-malignant B-cell lymphoma of the Burkitt type].

HISTORY AND CLINICAL FINDINGS: A 40-year-old man was admitted with acute onset of positional vertigo, nausea and vomiting. Neurological examination revealed a fatigable nystagmus to the upward ear in positional testing, to the right more than to the left, as well as latent paresis and rigidity of the left arm. INVESTIGATIONS: Magnetic resonance imaging of the brain revealed two space-occupying lesions in the cerebellum and pons. Open biopsy showed a highly malignant B-cell lymphoma of Burkitt type. There was no evidence of acquired or congenital immunodeficiency. As there were no significant abnormalities outside of the CNS, a primary lymphoma in this location was diagnosed. TREATMENT AND COURSE: Chemotherapy with a combination of drugs including methotrexate achieved only partial remission. Subsequent radiotherapy brought about full remission, which has now lasted for over a year. CONCLUSIONS: Treatment of first choice of a primary cerebral lymphoma in an immunocompetent patient is chemotherapy with cerebrospinal fluid-permeable cytostatics. Partial remission should be followed by radiotherapy.

Adult↗
PubMed1999

[Ilizarov reconstructive surgery--a solution for complex problems of the musculoskeletal system].

The Ilizarov technique is an important modality of reconstructive surgery for limb deformities, such as malunion and nonunion of fractures, persistent osteomyelitis, and bone loss following complex limb injuries, as well as in limb-lengthening procedures. It has received wide recognition in the Western world over the past decade. In MEDLINE we found 537 articles published between 1971-1995 that describe the use of this technique. Of these, only 18 were published between 1971-1975, while 261 were published between 1991-1995. The present paper describes the developments and updates in this method, as a result of the large experience gained by the authors in a number of centers in Israel using this technique. The Ilizarov apparatus is a circular frame that allows accurate control, much more than any other external fixator, during correction of limb deformities and limb-lengthening. It is minimally invasive, and open techniques and use of internal hardware and bone grafts are not needed. Based on our experience, we suggest that this method requires careful preoperative planning and meticulous surgical technique. More important, cooperation between surgeon and patient throughout the lengthy treatment is a prerequisite to ensure complete success, even in the most complicated cases.

Bone Diseases↗
PubMed1999

Tumor necrosis factor receptor-associated factor 1 is overexpressed in Reed-Sternberg cells of Hodgkin's disease and Epstein-Barr virus-transformed lymphoid cells.

The tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1) is a member of the recently defined TRAF family. It takes part in the signal transduction of the TNF receptor 2 (TNFR2), the lymphotoxin-beta receptor (LT-betaR), CD40, CD30, and LMP1; is induced by LMP1 in vitro; and protects lymphoid cells from apoptosis. To identify the cells in which TRAF1 is active in vivo, we studied TRAF1 transcripts in normal lymphoid tissue, in Epstein-Barr virus (EBV)-induced lymphoproliferations, and in malignant lymphomas with special reference to those that overexpress the cytokine receptor CD30 and CD40 of the TNF receptor family at the single-cell level using a radioactive in situ hybridization. In normal lymphoid tissue, TRAF1 message proved to be absent from all resting B and T cells as well as from macrophages and accessory cells (follicular dendritic cells and interdigitating cells) and present in few perifollicular and intrafollicular lymphoid blasts. In contrast, there was a high and consistent TRAF1 overexpression in EBV-induced lymphoproliferations and Hodgkin's disease. Nearly all non-Hodgkin's lymphoma show low or no TRAF1 expression. Only some cases of diffuse large B-cell lymphoma showed a moderate to high TRAF1 signal. Several of the latter cases were EBV+. These data confirm that TRAF1 is an inducible molecule and indicates its deregulation in the mentioned disorders with the potential of a blockage of the apoptotic pathway.

Epstein-Barr Virus Infections↗