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Biomedical subjects

B Klein

Publications and source records attributed to B Klein.

At least 91 records · Page 5Linked to original sources
PubMed1997

Using smoothing spline anova to examine the relation of risk factors to the incidence and progression of diabetic retinopathy.

Smoothing spline ANOVA (ANalysis Of VAriance) methods provide a flexible alternative to the standard parametric GLIM (generalized linear models) methods for analysing the relationship of predictor variables to outcomes with data from large epidemiologic studies. These methods allow the visualization of relationships not readily fit by simple GLIM models, and provide for the ability to visualize interactions between the variables. At the same time, they reduce to GLIM models if the data suggest that the added flexibility is unwarranted. Using this method, we investigate risk factors for incidence and progression of diabetic retinopathy in a group of patients with older onset diabetes from the Wisconsin Epidemiological Study of Diabetic Retinopathy. We carry out four analyses to illustrate various properties of this class of methods. Some of the results confirm previous findings with use of standard methods, while others allow the visualization of more complex relationships not evident from the application of parametric methods.

Adult↗
PubMed1997

Large scale and clinical grade purification of syndecan-1+ malignant plasma cells.

For cancer immunotherapy, it is usually necessary to obtain a large number of tumor cells from patients. We have previously reported that syndecan-I is present only on malignant plasma cells in samples from patients with multiple myelomatosis. We report here that this antigen is cleaved by chymopapain. This makes it possible to develop a rapid and clinical grade procedure to purify large numbers of myeloma cells using anti-syndecan-1 mAb, magnetic beads and chymopapain.

Chymopapain↗
PubMed1997

Apoptin induces apoptosis in human transformed and malignant cells but not in normal cells.

The chicken anemia virus protein apoptin induces a p53-independent, Bcl-2-insensitive type of apoptosis in various human tumor cells. Here, we show that, in vitro, apoptin fails to induce programmed cell death in normal lymphoid, dermal, epidermal, endothelial, and smooth-muscle cells. However, when normal cells are transformed they become susceptible to apoptosis by apoptin. Long-term expression of apoptin in normal human fibroblasts revealed that apoptin has no toxic or transforming activity in these cells. In normal cells, apoptin was found predominantly in the cytoplasm, whereas in transformed and malignant cells it was located in the nucleus, suggesting that the localization of apoptin is related to its activity. These properties make apoptin a potential agent for the treatment of a large number of tumors, also those lacking p53 and/or overexpressing Bcl-2.

Apoptosis↗
PubMed1997

[Biological test for menopausal osteoporosis].

Osteoporosis has become a major public health problem in many western countries in which about 25% of women by the age of 65 will have had osteopenic fractures. The most important contributing factor to this condition is loss of gonadal function. This progressive disease, characterized by reduction in bone mass, may be prevented by estrogen replacement therapy. While there are several methods of diagnosing the disease when already established, there is no method that can identify women at high risk of developing osteoporosis. We have developed a biological test in which the serum of postmenopausal women is added to rat osteoprogenitor cell culture and its influence on proliferation, differentiation and mineralization of bone cells is determined. The serum of 20 menopausal women was examined by the biological test and the results compared to the findings of dual photon absorptiometry. This showed that rapid bone-losers had a significantly lower mineralization index as compared to nonosteopenic women (p < 0.0001). The proliferation index (cell count) and alkaline phosphatase activity did not show significant differences between osteopenic and nonosteopenic groups. This preliminary study showed that a test based on serum reacting with a culture of bone cells to induce mineralization may be of value in the diagnosis of osteoporosis.

Absorptiometry, Photon↗
PubMed1997

Mastication and swallowing in patients with postirradiation xerostomia.

PURPOSE: Very little objective data has been reported on mastication and swallowing in xerostomic patients, which would substantiate presumed causal relationships between xerostomia and patient complaints. The purpose was to elucidate which components of mastication and swallowing were abnormal, and most directly related to xerostomia, and which appeared unaffected. METHODS AND MATERIALS: A retrospective analysis of timing events in mastication and swallowing was done using videofluoroscopic data for 15 cancer patients with xerostomia, and 20 normal controls. Scintigraphy was also used to determine oropharyngeal residue after a water swallow. Cancer treatment modalities included radiation therapy or chemoradiation therapy. RESULTS: For barium liquid and paste substances, timing measures were equivalent for controls and patients. Xerostomic patients took 46% longer to masticate a shortbread cookie, and timing for the initiation of swallowing was shorter, but duration of swallowing appeared unaffected. Oral and pharyngeal residues following the swallow were greater in the patient group. CONCLUSIONS: Xerostomia primarily affected mastication and oral manipulation of a dry, absorbent food material. Increased oral and pharyngeal residues after a water swallow are ambiguously related to xerostomia. The initiation and duration of the pharyngeal swallow was not abnormal.

Aged↗
PubMed1997

Major role of the soluble interleukin-6/interleukin-6 receptor complex for the proliferation of interleukin-6-dependent human myeloma cell lines.

Interleukin-6 (IL-6) is a proinflammatory cytokine which possesses a central growth factor activity for certain tumor cells such as plasma cells in multiple myeloma (MM). Upon binding of IL-6, soluble IL-6 receptor (sIL-6R) has been shown to retain its affinity for IL-6 and to associate with the signal-transducing gp130 chain. Therefore, contrary to the majority of soluble cytokine receptors, it plays an agonist role in IL-6 signaling. In order to test its physiological importance as compared to that of its membrane counterpart, we studied cells from two myeloma cell lines which need exogenous IL-6 to proliferate and release sIL-6R into their culture supernatant. Using a new culture system where the supernatant recirculated permanently through an anti-IL-6R affinity column, all sIL-6R was removed from the culture medium throughout the culture period. Under these conditions IL-6-dependent cells were unable to grow in the presence of physiological concentrations of IL-6, showing the major role of the sIL-6R for sustaining the proliferation of these cell lines. Increasing IL-6 concentrations well over the physiological values allowed the cells to proliferate again. No effect was seen when sIL-6R was removed from the supernatant of an IL-6-independent myeloma cell line. These results show that the levels of circulating sIL-6R (and thus those of IL-6/sIL-6R complex) are worth looking at in pathologies involving IL-6 hyperactivity.

Cell Division↗
PubMed1997

Specific inhibition of IL-6 signalling with monoclonal antibodies against the gp130 receptor.

A family of cytokines [IL-6, IL-11, oncostatin M (OM), leukaemia inhibitory factor (LIF), ciliary neurotrophic factor (CNTF) and cardiotrophin-1] involved in various inflammatory or tumoral diseases share the same gp130 signal transducer chain. The complex formed with their specific receptors associates with a common transducing gp130 membrane protein (gp130) resulting in the formation of high avidity receptor and activation of tyrosine kinases. With the view of identifying gp130 domains specifically involved in IL-6 signalling, the authors prepared 37 new anti-gp130 mAb and analysed the structure-function relationship of the molecule. By cross-competition ELISA, the mAb were classified in 10 subgroups called A to J. By ELISA and BIAcore analysis, the mAb were found to recognize at least 18 antigenic specificities of the gp130 chain. The mAb reacted against the soluble and the membrane forms of gp130 as well. Their ability to inhibit the proliferation of the human myeloma cell line XG-4 of which the growth is strictly dependent on the presence of either exogenous IL-6, or LIF, or OM, or CNTF was studied. Besides mAb with no evident neutralizing effect (G and H) and mAb which neutralized equally well the activity of all tested cytokines (all mAb of groups A, I and J), some showed a selective effect. Those of group F inhibited also the proliferation induced by the 4 cytokines, but more specifically that dependent on the CNTF. mAb of groups B and E specifically inhibited the growth induced by IL-6, whereas those of group C inhibited that induced by LIF and OM. These results show the presence of different gp130 epitopes specifically involved in the signaling induced by the cytokines of the gp130 family. In ELISA, only mAb of group B and E were found to inhibit the binding of the IL-6-IL-6R complex to gp130, showing that they identified one or two domains of gp130 involved in its interaction with the IL-6-IL-6R complex. Precise identification of this(ese) epitope(s) would be useful to better understand the mechanisms of the IL-6 signalling.

Animals↗
PubMed1997

Purification in quantity of the secreted form of WI-1: a major adhesin on Blastomyces dermatitidis yeasts.

WI-1, a 120-kDa adhesin on Blastomyces dermatitidis, binds the yeast to macrophages and is a major target antigen of immune recognition in acquired resistance to the fungus. In past studies, WI-1 has been purified by extracting the protein from the yeast cell wall, which yields microgram quantities for biological assays. We report a strategy for generating and purifying the secreted form of WI-1 in quantity. Yeasts of B. dermatitidis ATCC strain 60636 cultured in HMM medium were found to secrete 10 microg/ml of WI-1 into a supernate relatively free of other medium and yeast components. Using a two-step method of ion exchange and hydrophobic interaction chromatography, we achieved a 7.1-fold purification of WI-1. Purified WI-1 was sequenced at the N-terminus which revealed that the secreted protein exists in two different forms. In functional assays, purified WI-1 also retained its adhesivity for human macrophages, and its antigenicity in binding anti-WI-1 antibodies and stimulating T-cells to proliferate, but it lost some capacity to elicit delayed-type hypersensitivity in mice. These findings advance our understanding of the WI-1 adhesin/antigen and our ability to express and purify WI-1 in quantity and will permit a study of the relationship between three-dimensional structure and activity of the molecule.

Amino Acid Sequence↗
PubMed1997

Lymph node-revealing solution: simple new method for detecting minute lymph nodes in colon carcinoma.

PURPOSE: Detection of metastatic lymph nodes in colon cancer is essential for determining stage and, thus, therapeutic modalities. However, very small lymph nodes can easily be missed during routine examination. The aim of this study is to describe a new and easy technique for detecting tiny nodes in colonic specimens. METHODS: Thirty problematic cases, in which an unsatisfactory number of lymph nodes was found by the traditional method, were investigated. The entire mesocolonic fat was immersed for six hours in a lymph node-revealing solution (LNRS) composed of various traditional fixatives and fatty solvents. After six hours, the lymph nodes stood out as white, chalky nodules on the background of yellow fat. They were then excised, processed. and stained. RESULTS: Total number of lymph nodes found by the traditional method in the 30 cases was 88. After LNRS, 258 additional lymph nodes, measuring from 0.5 to 7 mm in largest diameter, were found. Of the 12 cases in which no lymph nodes were found by the traditional method, 8 became N0 and 4 became N1. Of the 14 cases first classified as N0, 4 became N1; of the 4 classified at first as N1, 2 became N2 after LNRS. Upstaging from Dukes B to C occurred in eight cases. Quality of the sections and histochemical and immunohistochemical stains after LNRS was similar to that of formalin-fixed tissues. CONCLUSIONS: LNRS is an easy, rapid, and inexpensive technique for detecting very small lymph nodes. These may contain metastases, a fact that changes the stage of disease and influences the mode of therapy.

Acetic Acid↗
PubMed1997

Deregulation of MUM1/IRF4 by chromosomal translocation in multiple myeloma.

The pathogenesis of multiple myeloma (MM), an incurable tumour causing the deregulated proliferation of terminally differentiated B cells, is unknown. Chromosomal translocations (14q1) affecting band 14q32 and unidentified partner chromosomes are common in this tumour, suggesting that they may cause the activation of novel oncogenes. By cloning the chromosomal breakpoints in an MM cell line, we show that the 14q+ translocation represents a t(6;14)x(p25;q32) and that this aberration is recurrent in MM, as it was found in two of eleven MM cell lines. The translocation juxtaposes the immunoglobulin heavy-chain (IgH) locus to MUM1 (multiple myeloma oncogene 1)/IRF4 gene, a member of the interferon regulatory factor (IRF) family known to be active in the control of B-cell proliferation and differentiation. As a result, the MUM1/IRF4 gene is overexpressed--an event that may contribute to tumorigenesis, a MUM1/IRF4 has oncogenic activity in vitro. These findings identify a novel genetic alteration associated with MM, with implications for the pathogenesis and diagnostics of this tumour.

Animals↗
PubMed1997

Lymph-node revealing solution: a new method for detecting minute lymph nodes in cystectomy specimens.

OBJECTIVE: To describe the use of a new lymph-node revealing solution (LNRS) for detecting lymph node involvement in total cystectomy specimens from patients with locally confined invasive transitional cell carcinoma (TCC) of the bladder, and to compare the results obtained with those using the conventional method (palpation and sectioning perivesical fat) that may fail to detect very small lymph nodes. MATERIALS AND METHODS: Of 12 cystectomy specimens obtained from patients with TCC, six in which 0-3 metastatic nodes were identified by the conventional method were further investigated using LNRS. The revealing solution comprised 95% ethanol, diethyl ether, glacial acetic acid and buffered formalin (65:20:5:10 v/v) prepared under a fume-hood. After evaluation using the conventional method, the specimens were immersed for 6-12 h in the solution, washed under running tap water and the adipose tissue sectioned at intervals of 2-3 mm. Lymph nodes were identified as white, chalky nodules against the background of yellow fat. The number of the lymph nodes identified by conventional and the LNRS methods was recorded and classified according the TNM system. RESULT: Twenty-two lymph nodes were detected by the conventional method, of which four were positive for tumour metastasis. Using the LNRS, an additional 21 nodes were identified among which 12 were positive. The mean size of the lymph nodes detected by the conventional and LNRS methods was 7.96 mm and 3.81 mm, respectively. The stage of three patients was increased (Nx to N2, N0 to N2 and N1 to N2) and therefore two of these patients received adjuvant chemotherapy. CONCLUSIONS: LNRS significantly enhanced the yield of normal and metastatic nodes of cystectomy specimens and may identify smaller nodes. The LNRS method allows a more accurate staging with better assessment of the prognosis and need for adjuvant therapy.

Carcinoma, Transitional Cell↗
PubMed1997

Rhinovirus-specific T cells recognize both shared and serotype-restricted viral epitopes.

To characterize rhinovirus (RV)-specific T cells, RV16- and RV49-specific CD4 T cells were cloned from peripheral blood, and cytokine secretion and serotype specificity were defined. Each RV-specific clone secreted high levels of interferon-gamma, and several also produced interleukin-4 and -5. To test serotype specificity, each clone was incubated separately with five different RV serotypes. Although 2 of 31 clones proliferated only in response to the virus used in cloning, the rest had significant proliferation in response to 2-5 different serotypes. Thus, RV-specific T cells can be activated by either serotype-specific or shared viral epitopes, raising the possibility that repeated activation of T cells by shared viral determinants in vivo could induce potent recall T cell responses. It is likely that enhanced T cell responses to shared viral epitopes contribute to antiviral activity, airway inflammation, or both.

Antigen-Presenting Cells↗
PubMed1997

Both human alpha/beta and gamma interferons upregulate the expression of CD48 cell surface molecules.

We have established a cDNA library from interferon (IFN)-treated human lymphoblastoid Daudi cells and made use of differential screening to search for yet unidentified IFN-regulated genes. In the course of these studies, we have isolated a human cDNA coding for the glycosyl-phosphatidylinositol-linked (GPI) membrane glycoprotein CD48 (TCT-1, Blast-1). Various studies demonstrated that the murine CD48 is the predominant counterreceptor for the mouse CD2 and is involved in the regulation of T cell activation. Since the murine CD48 is functionally homologous to the human CD2 ligand LFA-3 (CD48), the function of the human CD48 remains unknown. In this report, we show that both Hu-IFN-alpha/beta and Hu-IFN-gamma increase the level of CD48 mRNA and upregulate the expression of CD48 proteins at the surface of various cultured human cell lines. However, the IFN have no effect on the expression of LFA-3. In addition, we show that IFN increase CD48 expression on peripheral blood mononuclear CD3+, CD14+, and CD19+ subpopulations. These data suggest that in addition to modulation of the conventional MHC class I and class II-restricted interactions, the IFN might promote MHC-unrestricted interactions of target cells with the immune cells by inducing the expression of the cell surface CD48 molecule.

Antigens, CD↗
PubMed1997

Successful induction and consolidation therapy of acute myeloid leukaemia in a renal allograft recipient.

Immunosuppressed organ transplant recipients have a markedly increased risk of neoplasia. Among these malignancies acute myeloid leukaemia (AML) is rare. However, until now no case of successful chemotherapy has been reported. We present a 39-year-old male patient who developed AML (FAB M4 Eo) 4 years after renal transplantation and achieved a stable complete remission after induction therapy with standard dose cytarabine and daunorubicin. Remission duration is now 11 months. At present the transplant is functioning well after two additional courses of consolidation chemotherapy with high-dose cytarabine combined with mitoxantrone and idarubicine respectively. Cyclosporin A was given during all cycles of chemotherapy. We conclude that intensive chemotherapy in patients with AML following renal transplantation in good performance status is feasible.

Adult↗
PubMed1997

Lymph node revealing solution: a new method for detection of minute axillary lymph nodes in breast cancer specimens.

The staging and prognosis of patients with breast cancer is related to the presence or absence of axillary lymph node involvement. However, in some cases no lymph nodes or too small a number of lymph nodes are revealed by the traditional method of palpating and sectioning the axillary fat. In the present study we demonstrate the usefulness of the lymph node revealing solution (LNRS) in breast cancer. Specimens from 13 patients, in whom <10 lymph nodes were identified in the axilla by the traditional method, were included in the study. After excising the lymph nodes by the traditional method, axillary tissue was immersed in LNRS for 6-12 hours. Additional lymph nodes, which stood out as white chalky nodules, were excised and processed as usual. The LNRS increased the mean number of nodes per case from 6.0+/-2.5 found by the traditional method to 12.54+/-4.61 nodes per case (p < 0.01). The size of the nodes identified by the LNRS was significantly smaller (p < 0.01) than those detected by the traditional method. The LNRS changed the lymph node stage of the disease in four of the studied cases (30%). LNRS seems to be the technique of choice for detection of axillary lymph nodes in cases where the number of detected lymph nodes by the traditional method is too small for accurate staging.

Axilla↗
PubMed1997

Activation, binding, and processing of complement component 3 (C3) by Blastomyces dermatitidis.

Complement plays a key role in phagocyte recognition and killing of Blastomyces dermatitidis, but little is known about how complement components interact with the yeast. We report the characteristics of activation, binding, and processing of C3 by B. dermatitidis. In pooled normal human serum (NHS), deposition of C3 on the yeast was detectable within 2 min, whereas in NHS containing MgEGTA, deposition was delayed by 6 min, indicating that the yeast activates C3 by both classical and alternative pathways. When both pathways were operative, maximal binding of 4.5 x 10(6) C3 molecules/cell was achieved in less than 30 min. In the absence of the classical pathway, yeast cells bound 80% of the maximum C3, indicating that the yeast intrinsically activates the alternative pathway. Delayed deposition of C3 in NHS-MgEGTA was similar to that in NHS preabsorbed by the yeast or by immobilized protein A/G to remove serum immunoglobulin. Purified immunoglobulin restored C3 binding to NHS preabsorbed by the yeast, suggesting that antibody in nonimmune serum initiates the classical pathway. beta-Glucan absorption of NHS abolished the classical pathway, suggesting that cell wall beta-glucan is a target of initiating antibodies. Hydroxylamine treatment of NHS-opsonized yeast cells showed that 76% of C3 was bound to yeast cells by ester linkage, supporting a role for hydroxyl groups on cell wall polysaccharides. Hydroxylamine-cleaved fragments were chiefly C3b and iC3b; 70% of hydroxylamine-sensitive C3b was converted to iC3b within 1 min of opsonization, and the ratio was stable over 1 h. Our data predict that C3b and iC3b on opsonized yeast cells direct binding to CR1 and CR3 receptors on human phagocytes, which, in turn, may influence the fate of this host-pathogen interaction.

Blastomyces↗
PubMed1997

Interleukin-6 receptor antagonists inhibit interleukin-11 biological activity.

The IL-6 receptor system comprises two functionally different chains: a binding chain (IL-6R) and a signal-transducing chain (gp130). The IL-6/IL-6R complexes associate with gp130, induce its dimerization and signal transduction. When IL-6 is complexed to IL-6R, two distinct sites of IL-6 are able to bind gp130. Other cytokines-oncostatin M (OM), leukemia inhibitory factor (LIF) or ciliary neurotrophic factor (CNTF) also use the gp130 transducer and induce its heterodimerization with LIF receptor (LIFR). A series of IL-6 mutants have been generated which function as IL-6 receptor antagonists (IL-6RA). These IL-6RA carried substitutions that increased their affinity with IL-6R and abolished 1 or the 2 sites of interaction with gp130. All the IL-6RA inhibited wild-type IL-6. The IL-6RA with one mutated binding site to gp130 inhibited IL-11 activity. They did not affect those of CNTF, LIF and OM, even when used at a very high concentration at which virtually all membrane IL-6R were bound to IL-6RA. IL-6RA with two mutated gp130 binding sites did not affect IL-11, CNTF, LIF or OM activities. The results indicate that the interaction of one gp130 chain with IL-6R/IL-6R complexes inhibited further the dimerization of gp130 induced by IL-11/IL-11R but not its heterodimerization with LIFR. Thus these IL-6RA can also function as IL-11 antagonists.

Antigens, CD↗