Antigen-induced TCR-CD3 down-modulation does not require CD3delta or CD3gamma cytoplasmic domains, necessary in response to anti-CD3 antibody

We studied cytotoxic T lymphocyte (CTL) clones expressing cytoplasmic domain-deleted CD3delta and CD3gamma chains. These cells retained efficient antigen-specific cytolysis. Because the cytoplasmic domains of native CD3delta and CD3gamma chains contain a dileucine-based and a tyrosine-based motif thought to be important for receptor endocytosis, we compared TCR-CD3 down-modulation on the CTL clones expressing or not these domains. We found that antigen-induced TCR-CD3 down-modulation was not dependent on either the CD3delta or CD3gamma cytoplasmic domains. This contrasts with phorbol ester- and anti-CD3 mAb (soluble or plastic-coated)-induced TCR-CD3 down-modulation, that are respectively dependent on CD3gamma and on either CD3delta or CD3gamma cytoplasmic domains, suggesting that differences may exist between the mechanisms of TCR-CD3 down-modulation in response to the three stimuli. TCR-CD3 down-modulation in response to antigen was demonstrated by confocal microscopy to be associated with TCRbeta chain internalization, whether CD3delta and CD3gamma were native or truncated. Inhibition by the protein tyrosine kinase inhibitor PP1 of TCR-CD3 down-modulation in response to antigen was also similar whether CD3delta and CD3gamma cytoplasmic domains were present or not. These properties of receptor down-modulation are discussed with respect to the requirements for TCR engagement on antigen-presenting cells.

[How to plan the treatment of prostatic adenoma today?]

Surgical treatment, mainly transurethral resection of the prostate, still remains the reference treatment for benign prostatic hyperplasia (BPH). Two studies conducted in the Urology Department of the Pitié-Salpêtrière Hospital have tried to define certain characteristics of this surgery. The first study tried to evaluate the long-term outcome of patients operated for benign prostatic hyperplasia. Analysis of 881 replies to a questionnaire sent to 3,147 patients operated for BPH (between 1976 and 1989) assessed functional status (by Madsen's symptom score), quality of life (by Fowler's method), and sex life (by two specific questions), with a follow-up ranging from 5 to 14 years. At this follow-up, 90% of patients declared to be satisfied with their voiding status, 95% considered their quality of life to be excellent and about 50% had maintained a sex life. The second study was designed to evaluate the morbidity of this treatment in elderly patients. A group of 33 operated patients over the age of 80 was compared to a control group composed of 66 patients between the ages of 60 and 70 years, treated in a similar way, in the same centre and in the same year. Morbidity was higher in the first group, but age itself did not appear to constitute a poor prognostic factor for surgery; it only intervenes by allowing certain complications of benign prostatic hyperplasia (acute retention) to create emergency situations complicating the perioperative period. Following demonstration of the short-term and long-term efficacy of this conventional surgery, many new technologies were subsequently developed in order to reduce perioperative discomfort, anaesthetic requirements, duration of catheterization and hospital stay. Some of them constitute a new approach to endoscopic surgery, such as prostatic tissue vaporization techniques (electrovaporization, laser contact vaporization), which have a comparable efficacy to that of TURP, while reducing bleeding, catheterization time and hospital stay. However, the duration of postoperative irritative symptoms is much longer. Other techniques use a thermal effect to obtain coagulation necrosis of prostatic tissue, using various energy sources: microwaves (thermotherapy), laser (interstitial laser), radiofrequency waves (TUNA). These techniques are perfectly adapted to outpatient surgery with local or regional anaesthesia. They do not interfere with continence, sexual function, but may be followed by high dysuria or retention rates, with a variable cathererization time, sometimes several weeks. Finally, urethroprostatic stents are easy to insert, provide a solution in critical situations and have replaced old indwelling catheters. The current choice of treatment therefore comprises several approaches: more effective, but still purely symptomatic medical treatment, safe conventional surgery providing excellent long-term results, but generating a certain perioperative discomfort and a certain morbidity, or, on the contrary "minimally invasive" techniques, greatly simplifying the therapeutic procedure, but whose morbidity has not yet been determined and whose results are still uncertain.

Selection of phenotypically distinct NK1.1+ T cells upon antigen expression in the thymus or in the liver

Unlike the main TCR alphabeta T cell lineage in which deletion occurs at the CD4+ CD8+ double-positive (DP) stage upon TCR engagement by antigen in the thymus, some T cells appear to require such engagement for their selection, either in the thymus or extrathymically. We used a transgenic TCR (tgTCR) model which, as we previously showed, led to selection upon expression of the corresponding antigen H-2Kb (Kb) in the thymus, of tgTCR/CD3(lo) CD4- CD8- double-negative (DN) thymocytes that expressed the NK1.1 marker (NK T cells) (Curnow, S. J., et al., Immunity 1995. 3: 427). We now report that antigen expression on medullary epithelial cells of the thymus failed to select the NK T cells, whereas its expression on thymocytes did, although tgTCR DP thymocyte development was affected under both conditions. Antigen expression on hepatocytes (Alb-Kb mice) did not perturb tgTCR DP thymocyte development. No enrichment in tgTCR NK T cells was detected in the periphery, except for the liver of the Alb-Kb/tgTCR mice. When reconstitution of thymectomized and irradiated H-2k hosts expressing or not Kb was performed with bone marrow from tgTCR H-2k mice, an enrichment in tgTCR+ NK T cells was found in the liver, but not in the spleen, of the hosts which expressed Kb, either selectively on hepatocytes or ubiquitously. Surprisingly, the majority of the hepatic tgTCR+ NK T cells also expressed the CD8 alpha/beta heterodimer. These results indicate that thymus-independent NK T cells with unique phenotypic characteristics can be selected upon antigen encounter in the liver.

The Health On the Net Code of Conduct for medical and health web sites

The growth in the number of medical and health web sites and the varying quality of medical and health information currently available on the World-Wide Web has created the need for guidelines to help homogenise this quality. Health On the Net Foundation (HON) has initiated the Code of Conduct (HON-code) in response to concerns expressed to the Foundation, by members of the Net community. This article presents the HON-code's principles since its launch in 1996 and its status in 1997. This initiative offers information providers good practice guidelines and offers users an indication of commitment to quality by those providers.

A multi-agent softbot to retrieve medical information on Internet

World-Wide Web is a media where information is unstructured, distributed, multimedia and multilingual. Many tools have been developed to help users search for information: subject hierarchies, general search engines, browsers and search assistants. Although helpful, they show serious limitations, mainly in terms of precision, multilingual indexing and distribution. The M.A.R.V.I.N. project (Multi Agent Retrieval Vagabond on Information Networks) proposes solutions with a distribution of the indexing task in agents specialized in a given domain. M.A.R.V.I.N. has been successfully applied to the medical domain. The medical index and its associated search engine MedHunt (Medical Hunter) demonstrate the interest of such an approach with currently 50,000 indexed medical sites and more than 100,000 accesses each month.

K+-dependence of Na+-Ca2+ exchange in type I vestibular sensory cells of guinea-pig

The properties of the vestibular Na+-Ca2+ exchanger in mammalian type I vestibular sensory cells were studied using fura-2 fluorescence and immunocytochemical techniques. In the absence of external Na+, the activation of Na+-Ca2+ exchange in reverse mode required the presence of external K+ (K+o) and depended on K+o concentration. Alkali cations Rb+ and NH4+ but not Li+ or Cs+ substituted for K+o to activate the exchange. For pressure applications of 10 mm K+, the contribution of voltage-sensitive calcium channels to the increase in [Ca2+]i was < 15%. The dependence of the exchange on [K+]o was also recorded when the membrane potential was clamped using carbonyl cyanide p-trifluoromethoxy-phenylhydrazone (FCCP) and monensin ionophores. In these conditions, where there was no intracellular Na+, the increase in [Ca2+]i was completely blocked. These physiological results suggest that in reverse mode, Ca2+ entry is driven by both an outward transport of Na+ and an inward transport of K+. The dependence of the vestibular Na+-Ca2+ exchanger on K+ is more reminiscent of the properties of the retinal type Na+-Ca2+ exchanger than those of the more widely distributed cardiac type exchanger. Moreover, the immunocytochemical localization of both types of exchange proteins in the vestibular sensory epithelium confirmed the presence in the vestibular sensory cells of a Na+-Ca2+ exchanger which is recognized by an antibody raised against retinal type and not by an antibody raised against the cardiac type.

[Treatment of complicated renal colic in patients treated with indinavir: value of double J stents]

OBJECTIVE

Evaluation of the treatment of complicated ureteric stones in patients treated with indinavir.

PATIENTS AND METHODS

From March 1997 to May 1998, 10 patients (7 males, 3 females, aged 30 to 56 years), treated by triple combination therapy for HIV infection, were drained for stones attributed to indinavir (CRIXIVAN), which had become obstructive and complicated. The duration of treatment with indinavir ranged from 14 days to 2 years. No patient had a history of urological disease. One patient presented with bilateral stones. All patients presented complicated clinical features: fever in 3 cases; severe pain in 8 cases, with delayed excretion more than 4 hours on IVU in 6 cases. All stones were radiolucent except for one slightly radioopaque stone. The stone was situated in the lumbar ureter in 3 cases, iliac ureter in 1 case and pelvic ureter in 8 cases.

RESULTS

In 10 out of 11 cases, a double J stent was inserted, preceded by drainage by simple ureteric catheter (infected urine) in 1 case and by percutaneous nephrostomy (PCN) with antegrade insertion of the stent (failure of the retrograde route) in 1 case. No complementary stone fragmentation or extraction treatment was necessary after this procedure. Stents were left in place for 3 to 7 weeks. In one case, a stone of the lumbar ureter required PCN followed by extracorporeal lithotripsy.

CONCLUSION

In the case of complications requiring a urological procedure, insertion of a double J stent allows curative treatment of very friable indinavir stones, which are fragmented by passage of the stent.

Crippling of CD3-zeta ITAMs does not impair T cell receptor signaling

We evaluated the importance of CD3-zeta ITAMs in T cell responses by breeding the P14 transgenic TCR into mice in which CD3-zeta chains lacking all or part of their ITAMs were genetically substituted for wild-type CD3-zeta chains. In contrast to the H-Y TCR, the P14 TCR permitted the development of peripheral CD8+ T cells harboring signaling-defective CD3-zeta subunits. The absence of functional CD3-zeta ITAMs did not reduce the spectrum of activation events and effector functions that constitute the normal attributes of mature CD8+ T cells. The only detectable differences were quantitative and noted only when T cells were challenged with suboptimal peptide concentrations. Therefore, the ITAMs present in the CD3-gammadeltaepsilon module are sufficient for qualitatively normal TCR signaling and those present in CD3-zeta have no exclusive role during T cell activation.

[Internet for physicians: a tool for today and tomorrow ]

The Internet is becoming more and more part of our habits regarding documentation and communication, thus limiting the frontiers to only that of the language. As in many other fields, the Internet is also present in the medical domain. The Internet is accessible to all, providing a technology which is simple and ergonomic and furthermore less costly. A growing number of individuals are indeed offering information, and the multiplication and diversification of documentary thus resulting renders the quality often questionable and the search for information difficult. This article firstly presents the Internet services with examples in the medical domain and more particularly in paediatrics. It then identifies the problems related to the Internet and further details three tools useful to find medical information and to surf on the Internet: Medline, a bibliographical reference search tool (from the National Library of Medicine-NLM); Medhunt, a search tool of the Health on the Net Foundation specialised in the health domain; and the HONcode, a code of ethics developed to homogenize medical information on the Internet.

Fluorescent in situ hybridization on flow-sorted cells as a tool for evaluating minimal residual disease or chimerism after allogenic bone marrow transplantation

We studied the feasibility and the sensitivity of fluorescent in situ hybridization (FISH) using leukemic or host/donor-specific probes on flow-sorted cells to assess minimal residual disease (MRD) or chimerism in transplanted patients in complete remission. We first performed experimental models of MRD and chimerism by mixing HL60 cells and normal lymphocytes in different proportions. Over 80% HL60 cells were obtained from mixtures of 5% HL60 cells in peripheral blood mononuclear cells (PBMC). We then evaluated MRD and mixed chimerism in a chronic myelogenous leukemia patient in relapse after allogeneic sex-mismatched bone marrow transplantation (BMT), who had received a donor lymphocyte infusion (DLI). Three months after DLI, mixed chimerism was observed in each bone marrow (BM)-sorted lineage (CD13+, CD14+, CD20+, and CD3+), with the highest level of recipient cells in the granulocytic lineage (CD13+). Five months after DLI, host cells were at a low level but remained detectable in the granulocytic lineage. In the same sample, the bcr-abl gene was detected in the granulocytic lineage and not in the lymphocytes. We also studied chimerism in an aplastic anemia sex-mismatched transplanted female patient. We determined the proportion of recipient total lymphocytes, CD4+ and CD8+ lymphocytes, and CD14+ monocytes under cyclosporin A therapy on five peripheral blood samples and one BM sample over 5 months. Results showed a regular decrease in recipient total lymphocytes (26.6% to 10.6%) and monocytes (20.7% to 8%). CD8(+)-recipient cells decreased rapidly, while CD4+ remained stable (17%). This work demonstrates the feasibility of FISH after cell sorting, combining the sensitivities of both flow cytometry and FISH and the specificities of both immunophenotyping and genotype analysis.

The Health On the Net Code of Conduct for medical and health Websites

Internet has become one of the most used communication media. This and the fact that no constraining information publishing policy exists have created an urgent need to control the quality of information circulating through this media. To this purpose, the Health On the Net Foundation has initiated the Code of Conduct (HONcode) for the health/medical domain. This initiative proposes guidelines to information providers, with the aim, on the one hand, of raising the quality of data available on the Net and, on the other hand, of helping to identify Internet sites that are maintained by qualified people and contain reliable data. The HONcode mainly includes the following ethical aspects: the author's credentials, the date of the last modification with respect to clinical documents, confidentiality of data, source data reference, funding and the advertising policy. This article presents the HONcode and its evolution since it was launched in 1996.

Trends in medical information retrieval on Internet

Information on the World Wide Web is unstructured, distributed, multimedia and multilingual. Many tools have been developed to help users search for useful information: subject hierarchies, general search engines, browsers and search assistants. Although helpful, they present serious limitations, mainly in terms of precision, multilingual indexing and distribution. In this paper, we cover some on-line solutions to medical information discovery and present our own approach, the MARVIN (multi-agent retrieval vagabond on information network) project, which tackles medical information research with specialized cooperative retrieval agents. We also draw some outlines for future extensions.

Comparison of hippocampal dendritic spines in culture and in brain

We have quantified hippocampal spine structure at the light and ultrastructural levels in cell cultures approximately 1- 3 weeks old and in the brains of rodents 5 and 21 d old. The number of spines bearing synapses increases with age in cultures and in brain, but the structures are similar in both. In culture, about half of the synapses are formed on spines and the remainder are formed on dendritic shafts. In the 5-d-old brain, about half of the synapses occur on dendritic shafts, by 3 weeks of age only approximately 20% of synapses are found on dendritic shafts, and in the adult shaft synapses are very rare.

MARVIN, multi-agent softbot to retrieve multilingual medical information on the Web

The World-Wide Web is an unstructured, multimedia and multilingual information network. While most efforts have addressed the structuring issue, very few attempts have been proposed to provide support for multilingual information retrieval. Yet, medical information is now available all over the world. The MARVIN (Multi-Agent Retrieval Vagabond on Information Network) softbot and its associated medical search engine MedHunt (Medical Hunter) are a solution for helping people, who only understand a few languages, to access multilingual information.

Does a radiation dose-response relation exist concerning survival of patients who have soft-tissue sarcomas of the extremities? Radiation dose-response relation for soft-tissue sarcomas

This study analyzes a single-institution experience by evaluating the impact on survival of increasing total dose of adjunctive irradiation in patients who had extremity soft-tissue sarcoma (ESTS). A retrospective review of the tumor registry at a university medical center from January 1984 through December 1992 yielded a total of 59 surgical patients of ESTS. With follow-up ranging from 30 to 135 months (median, 65 months), the 2-, 5-, and 8-year overall and disease-free survival for all patients was 86%, 71%, 58% and 76%, 70%, 56%, respectively. Multivariate analyses using the Cox proportional hazards model revealed that total radiation dose (p = 0.02), American Joint Committee on Cancer stage (p = 0.04), and tumor size (p = 0.006) were all significant prognostic factors of overall survival; however, only tumor size was predictive of disease-free survival (p = 0.02). When the effect of tumor size and disease stage were controlled in the Cox model, a dose-response curve between increasing total radiation dose and improved overall patient survival was indicated. This study demonstrates the significance of tumor size on predicting both overall and disease-free survival in patients who have soft-tissue sarcomas of the extremity. It also suggests, however, that a radiation dose-response relation may exist for overall survival. Future investigations should consider evaluating the minimal total radiation dose needed to optimize patient survival after limb-sparing surgery.

Potassium depolarization of mammalian vestibular sensory cells increases [Ca2+]i through voltage-sensitive calcium channels

The existence of voltage-sensitive Ca2+ channels in type I vestibular hair cells of mammals has not been conclusively proven. Furthermore, Ca2+ channels present in type II vestibular hair cells of mammals have not been pharmacologically identified. Fura-2 fluorescence was used to estimate, in both cell types, intracellular Ca2+ concentration ([Ca2+]i) variations induced by K+ depolarization and modified by specific Ca2+ channel agonists and antagonists. At rest, [Ca2+]i was 90 +/- 20 nM in both cell types. Microperifusion of high-K+ solution (50 mM) for 1 s increased [Ca2+]i to 290 +/- 50 nM in type I (n = 20) and to 440 +/- 50 nM in type II cells (n = 10). In Ca2+-free medium, K+ did not alter [Ca2+]i. The specific L-type Ca2+ channel agonist, Bay K, and antagonist, nitrendipine, modified in a dose-dependent manner the K+-induced [Ca2+]i increase in both cell types with maximum effect at 2 microM and 400 nM, respectively. Ni2+, a T-type Ca2+ channel blocker, reduced K+-evoked Ca2+ responses in a dose-dependent manner. For elevated Ni2+ concentrations, the response was differently affected by Ni2+ alone, or combined to nitrendipine (500 nM). In optimal conditions, nitrendipine and Ni2+ strongly depressed by 95% the [Ca2+]i increases. By contrast, neither omega-agatoxin IVA (1 microM), a specific P- and Q-type blocker, nor omega-conotoxin GVIA (1 microM), a specific N-type blocker, affected K+-evoked Ca2+i responses. These results provide the first direct evidence that L- and probably T-type channels control the K+-induced Ca2+ influx in both types of sensory cells.

Health On the Net automated database of health and medical information

With the number of World Wide Web sites growing every day, the problem is not just to find information, but to locate the right piece of information. Current World Wide Web search engines have not resolved this problem as they most often return a long list of documents. The search result is then unusable because of the large number of answers from different domains and topics. Only complex queries may, in a given situation, produce a limited number of potentially relevant documents. To make searches more efficient and usable by common users, we now need intelligent and specialised search engines on the Net [1,2]. Health On the Net Foundation and the Molecular Imaging and Bioinformatics Laboratory at Geneva University Hospital have developed Multi-Agent Retrieval Vagabond on Information Networks (MARVIN), a robot that searches sites and documents specifically related to a given specialised field. One such robot has already been implemented and used for the medical and the 2D electrophoresis domains. Health On the Net Foundation has implemented the corresponding search engines, MedHunt (http://www.hon.ch/cgi-bin/find) for the medical field and 2DHunt (http://www.hon.ch/cgi-bin/2DHunt/find) for the 2D electrophoresis field.

Spontaneous rupture of orthotopic detubularized ileal bladder replacement: report of 5 cases

PURPOSE

We defined the mechanisms responsible for rupture of orthotopic, detubularized ileal bladder replacement.

MATERIALS AND METHODS

We reviewed retrospectively the records of 5 cases of ileal neobladder rupture treated at our center between 1985 and 1995.

RESULTS

The interval to perforation varied from 3 to 60 months after surgery. The perforation site was typically the upper part of the right limb of the reservoir. We observed an acute episode of bladder over distension immediately before perforation in 2 cases and a chronic state of neobladder over distension in the 3 remaining cases. Bacterial infection was associated in 4 cases. Intraperitoneal adhesions were an associated mechanism for rupture in only 1 case. We found chronic ischemic changes weakening the bladder wall to be an additional factor for rupture in the 3 cases associated with chronic over distension.

CONCLUSIONS

Acute or chronic over distension of the neobladder is the main factor for spontaneous rupture of orthotopic detubularized ileal bladder replacement. Chronic ischemic changes of the bladder wall, possibly facilitated by detubularization and the variability of the mesenteric circulation, are additional factors that lead to perforation.

Heregulin and agonistic anti-p185(c-erbB2) antibodies inhibit proliferation but increase invasiveness of breast cancer cells that overexpress p185(c-erbB2): increased invasiveness may contribute to poor prognosis

Overexpression of p185(c-erbB2) (p185/NEU/HER2) by tumor cells is associated with a poor prognosis in many but not all studies of breast and ovarian cancer. The poor prognosis associated with overexpression of p185(c-erbB2) could result from an increased growth rate or increased invasive potential. The p185(c-erbB2) tyrosine kinase receptor can be activated with agonistic antibodies directed against p185(c-erbB2) or with the ligand heregulin through a combinatorial interaction with erbB3 or erbB4. Consequently, we have asked whether heregulin or agonistic antibodies increase anchorage-independent growth or invasiveness of the SKBr3 breast cancer cell line, which overexpresses p185(c-erbB2). Incubation of SKBr3 breast cancer cells with heregulin inhibited anchorage-independent growth while enhancing tyrosine phosphorylation of p185(c-erbB2). Heregulin treatment also increased adhesion of SKBr3 cells to plastic and increased invasiveness of tumor cells into Matrigel membranes while increasing expression of the CD44 (HCAM) and CD54 (ICAM-1) adhesion molecules. Tumor cell invasion of Matrigel membranes was partially blocked by either anti-CD44 or anti-CD54 antibodies, indicating a role for these adhesion molecules in the invasion process. Compatible with the increased invasiveness, heregulin increased expression of the matrix metalloproteinase 9. In contrast, the agonistic anti-p185(c-erbB2) antibody ID5 induced only a subset of the responses induced by heregulin. ID5 induced tyrosine phosphorylation of p185(c-erbB2), increased invasiveness, and increased expression of CD44. Despite the similarity of effects of ID5 and heregulin on some outcomes, the ID5 antibody failed to increase adhesion to plastic, expression of CD54, or production of matrix metalloproteinase 9. Thus, the ID5 agonistic anti-p185(c-erbB2) antibody mimics rather than antagonizes some but not all of the actions of heregulin. Moreover, the poor prognosis of breast and ovarian cancers that overexpress p185(c-erbB2) could relate in part to enhanced invasiveness rather than to increased proliferative capacity.

Role of CD3gamma and CD3delta cytoplasmic domains in cytolytic T lymphocyte functions and TCR/CD3 down-modulation

TCR engagement leads to down-modulation of TCR/CD3 complexes from the T cell surface. The importance of this effect in T cell physiology is unknown. Here, we characterized a CTL clone deficient in TCR/CD3 surface expression that had lost both CD3delta and CD3gamma mRNA, allowing us to address the role of these chains in the assembly, signaling, and dynamics of the TCR/CD3 complex. Expression of either CD3delta or CD3gamma alone failed to reconstitute surface expression of the TCR/CD3 complex, but reconstitution with a cytoplasmically truncated CD3delta (delta t) and a native (gamma) or cytoplasmically truncated (gamma t) human CD3gamma led to reexpression of TCR/CD3 complexes in both cases. This indicated that CD3delta and CD3gamma assume specific functions in TCR/CD3 assembly independently of their cytoplasmic domains. The delta t gamma t variant specifically killed target cells, expressed the IFN-gamma gene in response to Ag, and produced TNF-alpha in response to anti-CD3 mAb, but it was affected in CD3 ligand-induced TCR/CD3 down-modulation. Both PMA- and CD3 ligand-induced TCR/CD3 down-modulation were defective in the delta t gamma t variant, whereas the delta t gamma variants were unaffected, and previously described delta gamma t variants were affected only in PMA-induced down-modulation. Specific protein kinase C (PKC) inhibitors indicated that PMA- but not CD3 ligand-induced down-modulation was dependent on PKC activity. Thus, amino acid sequences present in either the CD3delta or CD3gamma cytoplasmic domain control ligand-induced TCR/CD3 down-modulation, and neither these sequences nor this property are required for cytolysis and IFN-gamma gene expression in response to Ag.