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R Chiari

Publications and source records attributed to R Chiari.

At least 19 recordsLinked to original sources
PubMed2001

High frequency of cytolytic T lymphocytes directed against a tumor-specific mutated antigen detectable with HLA tetramers in the blood of a lung carcinoma patient with long survival.

We have identified an antigen recognized by autologous CTL on the lung carcinoma cells of a patient who enjoyed a favorable clinical evolution, being alive 10 years after partial resection of the primary tumor. The antigenic peptide is presented by HLA-A2 molecules and encoded by a mutated sequence in the gene coding for malic enzyme, an essential enzyme that converts malate to pyruvate. In the tumor cell line derived from the patient, only the mutated malic enzyme allele is expressed, because of a loss of heterozygosity in the region of chromosome 6 that contains this locus. Tetramers of soluble HLA-A2 molecules loaded with the antigenic peptide stained approximately 0.4% of the patient's blood CD8 T cells. When these cells were stimulated in clonal conditions, 25% of them proliferated, and the resulting clones were lytic and specific for the mutated malic enzyme peptide. T-cell receptor analysis indicated that almost all of these antimalic CTLs shared the same receptor. Antimalic T cells were consistently found in blood samples collected from the patient between 1990 and 1999, at frequencies ranging from 0.1 to 0.4% of the CD8 cells. Their frequency appeared to double within 2 weeks after intradermal inoculation of lethally irradiated autologous tumor cells. These results indicate that nonmelanoma cancer patients may also have a high frequency of blood CTLs directed against a tumor-specific antigen.

Amino Acid Sequence↗
PubMed2000

Identification of a tumor-specific shared antigen derived from an Eph receptor and presented to CD4 T cells on HLA class II molecules.

We obtained a lytic CD4 T-cell clone that recognized an antigen presented by HLA-DRB1*1101 on the tumor cells of a melanoma patient who enjoyed an unusually favorable clinical evolution. The antigen appeared to be shared between several melanoma cell lines. To identify the encoding gene, we used a new method, based on the cotransfection into human embryonal kidney cell line 293 of a cDNA library from the tumor together with a cDNA clone encoding the class II transactivator, which induces the expression of HLA class II molecules. The product of the gene coding for the antigenic peptide is EphA3, a member of the Eph family of tyrosine kinase receptors, which mediate the repulsion of neural cells by cells carrying the ligand Ephrins on their surface. EphA3 is expressed at a high level in the retina and fetal brain, at a lower level in several normal tissues, and not at all in hematopoietic cells, the only cells that constitutively express HLA class II molecules. It is overexpressed in several types of tumors, including melanoma, lung carcinoma, and sarcoma. On the basis of this pattern of expression, EphA3 may be a source of tumor-specific antigens recognized on tumor cells that express HLA class II molecules. Anti-EphA3 T cells may have participated in a tumor rejection response in the patient, because the cells of metastases collected several years later than the metastasis used to characterize the antigen had lost expression of HLA-DR or EphA3, therefore escaping recognition by these lymphocytes.

Amino Acid Sequence↗
PubMed1999

Two antigens recognized by autologous cytolytic T lymphocytes on a melanoma result from a single point mutation in an essential housekeeping gene.

We have pursued our analysis of antigens recognized by autologous cytolytic T lymphocytes (CTLs) on the melanoma cells of patient LB33. This patient enjoys an unusually favorable evolution, which is associated with a strong and sustained antitumor CTL response. We reported previously the analysis of two melanoma cell lines, MEL.A and MEL.B, which were derived from metastases removed from the patient at 5 years' distance. Autologous CTL clones derived from blood lymphocytes recognized several antigens presented by different HLA class I molecules on MEL.A. The MEL.B cells resisted lysis by these CTLs because they have lost expression of most HLA molecules, suggesting that they were selected in vivo by the anti-MEL.A CTL response. One of the MEL.A antigens was shown to result from a point mutation in the tumor. Here we report the cloning of a gene that encodes two other MEL.A antigens. This new gene, MUM-2, is expressed ubiquitously. In the melanoma cells of patient LB33, it contains a point mutation that changes one amino acid in the translated protein. Two different antigenic peptides, one presented to CTL by HLA-B44 molecules and another by HLA-C6 molecules, overlap and contain the mutated residue. Gene MUM-2 is homologous to an essential yeast gene, bet5, that was recently shown to be implicated in the vesicular transport of proteins from the endoplasmic reticulum to the Golgi. In a mutant yeast with a disrupted bet5 gene, both the wild-type and the mutated MUM-2 genes could complement for bet5 function. These results indicate that the antigenic mutation does not destroy the function of the protein, a function that is conserved in eukaryotic cells. The identification of these antigens suggests that point mutations could be the major cause of the strong immunogenicity of MEL.A cells.

Amino Acid Sequence↗
PubMed1999

Antitumor immunity at work in a melanoma patient.

This review covers the results obtained so far with a chronological analysis of the antitumor cytolytic T lymphocyte (CTL) cell response of a melanoma patient who enjoys an unusually favorable evolution. Two melanoma cell lines, MEL.A and MEL.B, were derived from metastases removed from the patient in 1988 and 1993, respectively. The patient developed a very strong CTL response against the MEL.A cells. Several antigens on these cells, presented by various HLA class I molecules, result from point mutations present in the genome of the tumor. The MEL.B cells, on the other hand, resist lysis by these CTLs because they have lost expression of most HLA class I molecules, suggesting that they were selected in vivo by the anti-MEL.A CTLs. New CTLs recognize MEL.B cells specifically, however. Analysis of their specificity indicates that they carry inhibitory receptors similar to those present on natural killer (NK) cells. These results illustrate the relationship between a tumor and the immune system in vivo over a period of several years. They are discussed in the context of the recent identification of many human tumor antigens recognized by CTLs, and the perspectives of specific immunotherapy opened up by these discoveries.

Cytotoxicity, Immunologic↗
PubMed1997

Shc mediates IL-6 signaling by interacting with gp130 and Jak2 kinase.

IL-6 is a multifunctional cytokine involved in hemopoiesis, immune regulation, inflammation, neural development, and infection. IL-6 belongs to a family of related cytokines that includes leukemia inhibitory factor, oncostatin M, IL-11, ciliary neurotropic factor, and cardiotropin-1, all of which initiate signaling through a receptor-associated gp130. IL-6 induces homodimerization of gp130 and activates the Jak/STAT pathway of signal transduction. In addition, IL-6 stimulates the mitogen-activated protein kinases designated ERK (extracellular signal-regulated kinase)-1 and -2. Activation of ERK-1 and -2 may involve the Src homology-2 containing proteins Shc and Grb2. Here we provide evidence that Shc could function as signaling molecules for IL-6 in DeFew-IL-6R/gp130 cells, a human B lymphoma cell line engineered to express high levels of both the IL-6R (p80) and the gp130 subunit. IL-6 was shown to promote the rapid tyrosine phosphorylation of gp130, Jak2, and Shc proteins. Moreover, Shc associated both in vivo and in vitro with phosphorylated gp130 through the Shc-Src homology-2 domain. We also report that Shc bound to activated Jak2 by using the Shc amino terminal phosphotyrosine interaction domain. Following IL-6 stimulation, Shc physically associated with Grb2. Thus, the data point to Shc proteins as a functional link between the Jak2 and Ras pathways of IL-6 signal transduction.

Adaptor Proteins, Signal Transducing↗
PubMed1996

The aminoterminal phosphotyrosine binding domain of Shc associates with ZAP-70 and mediates TCR dependent gene activation.

T-cell antigen receptor stimulation results in recruitment to the zeta chain and phosphorylation both of the syk family protein tyrosine kinase ZAP-70 and of the Shc adaptor protein, which transduces activating signals to Ras. Both ZAP-70 and Ras are required for T-cell activation. We have investigated the functional link between these two molecules in TCR signaling. She was found to associate with ZAP-70 in response to TCR triggering. This association was dependent on the presence of the aminoterminal phosphotyrosine binding (PTB) domain of She. The analysis of She binding to a potential PTB domain binding site on ZAP-70 confirmed the interaction of the She PTB domain with ZAP-70 and identified the ZAP-70 phosphotyrosine residue involved in this interaction. To test the role of the She PTB domain in transducing TCR derived signals we measured the effects of the isolated She PTB domain on the activation of the T-cell specific transcription factor NF-AT. The isolated She PTB domain was designed to compete non productively with endogenous She for binding to up-stream tyrosine phosphorylated proteins and thus interfere with coupling to regulators of Ras activation. A significant inhibition of NF-AT activation by TCR triggering was observed, showing a functional involvement of She in TCR signaling through its PTB domain and suggesting an important role for She association with ZAP-70.

Amino Acid Sequence↗
PubMed1995

Analysis of protein-protein interactions involved in the activation of the Shc/Grb-2 pathway by the ErbB-2 kinase.

In murine fibroblasts activation of the Shc/Grb-2 pathway by the ErbB-2 kinase involves tyrosine phosphorylation of Shc products and the formation of Shc/ErbB-2, Shc/Grb-2 and Grb-2/ErbB-2 complexes. Tyr 1139 of ErbB-2 bound to the Grb-2 SH2 domain in vitro as well as in intact cells. Tyr 1221 and 1248 are binding sites of gp185ErbB-2 for Shc SH2 domain in vitro whereas Tyr 1196 and 1248 are major binding sites of ErbB-2 for Shc PTB domain. Inhibition of Shc/ErbB-2 complex formation in intact cells was obtained by simultaneous mutational inactivation of Shc SH2 and Shc PTB binding sites of gp185ErbB-2. Shc/ErbB-2 complexes are formed upon activation of the ErbB-2 kinase and tyrosine phosphorylation of Shc proteins; they are located in both cytosol and cellular membranes. ErbB-2 activation induces also translocation of Grb-2 from cytosol to membranes. This network of protein-protein interactions may reflect the ability of the Shc/Grb-2 pathway to act as a molecular switch controlling different cellular functions regulated by RTK activation. In fact the Ras GDP exchanger mSOS was recruited in Grb-2/ErbB-2 complexes; furthermore besides mSOS, other polypeptides present in either cytosolic or membrane preparations were able to complex in vitro with Grb-2 SH3 domains.

3T3 Cells↗
PubMed1992

[Internal urethrotomy].

Internal urethrotomy is the first treatment for all kinds of urethral strictures except meatal stenosis and complete urethral obstruction. After urethrotomy a urethral catheter is left indwelling for up to 3 days if the urine is already sterile. In the case of infection it remains in place for 2 weeks. Long-term results depend mainly on the extent of periurethral fibrosis. The over-all success rate is about 50%. Only in a few cases can a second or third urethrotomy be definitively curative. Further urethrotomies are clearly only a palliative treatment of the stricture, comparable in effect to repeated urethral dilatation.

Cicatrix↗
PubMed1985

[Extent of natural variation of the longitudinal axis of the kidney collecting system].

Since the position of the longitudinal axis of the renal pelvis is of special significance in the diagnosis of the renal masses, the physiological range of the angle formed by this axis and the spine was determined by retrospective evaluation of 516 urograms. Up to the age of 11, in boys and girls the angle increases without side difference. In the adult, the position of the kidney is more transverse in men than in women, the left angle being smaller than the right one in both, male and female. The lateral contour of psoas muscle changes in similar fashion except for the side difference. Moreover, the decrease in size of the adrenal glands in early childhood is thought to be responsible for the rotation of the kidneys. Neither the kidney's shape nor its position respective to the spine proved significant for the position of the axis. The right kidney constantly being in a position nearly one vertebra lower than the left one, both sink caudad about 2/3 of a vertebra after the age of 50.

Adolescent↗
PubMed1983

Urethral obstruction and prostatitis.

Urethral destruction is only occasionally the reason for prostatitis and Cowperitis and prostatitis is only demonstrated occasionally to complicate urethral stricture. It is a dependence of prostatitis and spastic urethral obstruction in the neuropathic bladder.

Bulbourethral Glands↗
PubMed1983

[Comparative studies of renosonography and intravenous pyelography prior to and following hysterectomy].

Prior to hysterectomy investigation of the upper urinary tract and documentation of the investigation is important for treatment and liability reasons. The X-ray exposure possible allergy to the dye and the high price of intravenous pyelography mitigates against the investigation. This prospective study of 155 patients with benign disease shows that sonography is a valuable screening procedure. In over 90% of the cases sonography was sufficient and in only 11 women additional intravenous pyelography was necessary. The incidental discovery of an assymptomatic carcinoma of the kidney and of a hydronephrosis emphasized the importance of the pre-operative investigation of the upper urinary tract. Only displacement and mild dilatation of the distal ureters is not detectable by sonography. Therefore in malignant tumours of the genital tract the pre-operative intra-venous pyelogram is still recommended.

Adult↗
PubMed1980

Complications after extravesical antireflux operations.

The antireflux operation according to Lich-Grégoir (L-G) poses no particular technical problems and involves no major surgical stress to the patient. Of its intraoperative complications lesions to the bladder mucosa have to be considered in the first place. Its postoperative complications calling for reoperation comprise recurrence of reflux, ureteral stricture and ureteral fistula. Results of the Lich-Grégoir operation performed in 176 instances are reported. The complication rate was 4.5 per cent. The complications are commented upon, and the types and time of reoperations are discussed.

Child↗
PubMed1980

[Dissection of spermatoceles and fertility (author's transl)].

The majority of spermatoceles originate in retention cysts of the vasa efferentia. Cystic embryonic remnants of the testis and epididymis are not so frequent. Only 10 of 20 patients undergoing surgical treatment of unilateral, singular spermatoceles preoperatively showed normozoospermia. Excision of the spermatocele in more than 50% of our patients caused permanent deterioration of their spermiogramm. The number of sperms was reduced to less than the half of the preoperative counts. Obstruction of the epididymal duct caused by postoperative cicatrices is thought to be the reason. In consequence of these results operative treatment of spermatoceles should be though over. Our series clearly shows that the dissection of a spermatocele by no means should be practiced by way of treating infertility.

Adult↗
PubMed1978

[Indirect lymphography of the urinary bladder in animal experiments (author's transl)].

Of three contrast media injected interdigitally and submucosally as well as instilled into the bladder, Lipiodol UF (particle size of over 15 micron) and the experimental compound AG 52-315 were not resorbed. Another experimental compound (AG 60-99) with an iodine content of 20% and a particle size of ca. 3,5 micron produced, when injected interdigitally, good contrast of the popliteal lymph nodes in all cases (n = 5). Instillation of the same contrast medium into the bladders of five dogs yielded subdued contrast of the paravesicular lymph nodes in one case. Of still another five animals, two showed contrast of the inner iliac lymph nodes after submucosal infiltration of the bladder mucosa with AG 60-99. In all cases (n = 15) inflammatory reaction with necrotic formations were observed. Resorption of the contrast medium was accomplished by heating at 39 degrees C, and was not improved by addition of Hyaluronidase. Because of the low local tolerance of the contrast medium preparation, this successful experiment in indirect lymphography of the urinary bladder of animals cannot be applied clinically.

Animals↗