An improved method for purifying human thymic dendritic cells

Thymic dendritic cells (DC) play a prominent role in the immune response as they constitute a key element involved in the maturation of thymocytes in the thymus. Human thymic DC, like DC from other lymphoid organs, represent a minor cell population (< 2%) of the thymus. Since these cells cannot replicate in vitro, the development of efficient purification methods is an essential prerequisite for extensive functional studies. DC express high levels of HLA-DR, a cell surface marker of the MHC class II antigen which is not exclusive to DC. Since no specific human thymic DC marker has been identified so far, DC purification methods are mainly based on depletion of particular subgroups of cells. We report here an improved method for purifying human thymic dendritic cells. In contrast to prior work, CD2+ thymocytes were first depleted by rosetting with neuraminidase treated sheep red blood cells. The nonrosetted cells were separated in a Percoll gradient, and the low-density cells were subsequently depleted of nondendritic cells by using thymocyte and macrophage specific monoclonal antibodies and either magnetic bead depletion or cytofluorometry. Cell populations (18-55 x 10(6) cells) obtained following magnetic bead purification were at least 80% HLA-DR+/CD2- and exhibited ultrastructural morphological features and functional activities such as those described previously for thymic DC. This improved method was compared with different purification approaches that use various combinations of cell density-based separation techniques and cell surface specific markers antibody reactivity. The magnetic beads depletion approach provided higher yields.

Rural Minnesota family physicians' attitudes toward telemedicine

This study reports the results of an assessment of the attitudes and opinions of rural Minnesota family physicians toward telemedicine. The results of 52 mail surveys and 32 telephone interviews were compiled to determine existing attitudes and levels of awareness concerning aspects of telemedicine. Surveyed physicians overwhelmingly agreed that they do not have sufficient information about telemedicine. Their awareness of telemedicine's applications and capabilities is minimal. Also, responding physicians indicated little knowledge regarding such important issues as cost-effectiveness, reimbursement, liability, and potential primary care benefits. In general, however, physicians' attitudes toward telemedicine were favorable. This information should be important to funders, suppliers, and potential users of telemedicine. This study suggests a need to educate medical students, residents, and practicing physicians about telemedicine and issues related to its use.

Recruitment of family physicians in rural practice

We report the results of a study to find out how rural family physicians choose their practice location--information that could allow physicians and practices to be more appropriately and easily matched. We interviewed rural family physicians who completed a Minnesota residency in 1990 or 1991 to determine what factors influenced their final practice selection. The survey revealed that partners in practice are physicians' greatest concern, followed by geographic location, recreational activities, call schedule, and opportunities for spouse and children. Despite numerous available practice options, it was difficult for physicians to find practices and communities that met the majority of their personal, professional, and familial needs. This study suggests a need for a physician placement network that would increase retention and help ease the current health care provider shortage in rural Minnesota.

Long-range mapping of the 11q23 region involved in chromosome aberrations in human tumors by pulsed-field gel electrophoresis with a yeast artificial chromosome

We have previously demonstrated that the RCK gene involved in t(11;14)(q23;q32) and the more centromeric MLL/ALL1 gene involved in t(4;11)(q21;q23) and t(11;19)(q23;p13) are localized on different adjacent NotI fragments by using pulsed-field gel electrophoresis (PFGE) analysis with the yeast artificial chromosome (YAC) clone yB22B2. The PFGE analysis using the YACs of YTY17 containing the prophobilinogen deaminase (PBGD), CBL2 and THY1 genes and yB22B2 allowed the following ordering of genes and breakpoints from CD3 to THY1 on 11q23: cent-CD3-ALL/MLL1-RCK-PBGD-CBL2-THY1, and the establishment of a long-range restriction map covering these genes. In addition, we showed that the FLI1 region involved in the t(11;22)(q24;q12) in Ewing's sarcoma was more telomeric region that the THY1 gene by analyzing somatic cell hybrids carrying the 11q- and/or 14q+ chromosome of the t(11;14)(q23;q32) translocation, and by PFGE analysis of the YAC clone YTY17.

Sequence and expression of a gene encoding a protein with RNA-binding and glycine-rich domains in Brassica napus

A cDNA clone and its genomic counterpart were isolated from Brassica napus. The encoded protein, BnGRP10, is composed of two modules, the first one is homologous to many RNA-binding domains of ribonucleoproteins, and the second is 73% glycine rich. Northern analysis shows that this gene is expressed only in roots and stems and is slightly induced by different stress conditions.

Expression and DNA rearrangement of proto-oncogenes in Cas-Br-E-induced non-T-, non-B-cell leukemias

The Cas-Br-E murine leukemia virus is a non-defective retrovirus that induces non-T-, non-B-cell leukemias in susceptible NIH/Swiss mice. A collection of tumors was examined for genomic DNA structure and RNA expression of known or putative proto-oncogenes and one tumor-suppressor gene, with the aim of identifying genes involved in Cas-Br-E-induced non-T-, non-B-cell leukemogenesis. Fli-1, p53, and Evi-1 were found to be rearranged in 72%, 23%, and 18% of the tumors, respectively, whereas no DNA alteration were detected for c-myc, c-myb, Pim-1, Evi-2, and EpoR genes. Evi-1 rearrangements are rarely associated with p53 or Fli-1 alterations. However, rearrangements of these last two genes are very often associated within the same tumor. Moreover, patterns of coordinated expression of critical cell growth-regulating genes are consistently associated with specific tumor types. These data suggest that Cas-Br-E can induce two types of hematopoietic neoplasias by different mechanisms.

Biochemical and morphological characterizations of DU-145 cell mortality in rabbit embryo-fetal fluid

Rabbit embryo-fetal fluid (EFF) contains regulatory factors of cell proliferation which increase the duration of the cell cycle, induce a quiescent status in some cells and lead up to cell death in others. The objective of this study was to demonstrate which of the two processes, namely necrosis or apoptosis, was responsible for the cell death. Inhibitors of protein synthesis, and nuclease and phospholipase A2 activities did not restore the viability of the cells treated with EFF. Using a combination of DNA labelling and extraction, it was possible to show that a large proportion of DNA was fragmented in the cells released in the supernatant while only a very small portion of DNA was fragmented in the monolayer cells. EFF did not induce fragmentation of DNA into nucleosome-sized subunits as analysed using polyacrylamide gel electrophoresis. Nevertheless, using cytofluorometric analysis, it was possible to demonstrate that 50% of the cells released in the supernatant contained a lower quantity of DNA per cell than in the control cells. This was also observed with EFF-treated monolayer cells but not in the control monolayer cells. The reduction of the DNA content per monolayer cell became significant at 48 h of treatment with EFF. Electron microscopic analysis did not reveal blebbing of the cells. However, depletion of glycogen, condensation of mitochondria and increasing number of lysosomes and residual bodies were observed upon treatment with EFF. From these experiments we conclude that the DU-145 cells treated with EFF do not die by apoptosis, but rather seem to die by necrosis.

Analysis of proviruses integrated in Fli-1 and Evi-1 regions in Cas-Br-E MuLV-induced non-T-, non-B-cell leukemias

The DNAs of the Cas-Br-E MuLV-induced leukemias always contain somatically acquired mink cell focus-forming (MCF) recombinant proviruses. MCF recombinants could be involved during leukemogenesis at both preleukemic times and in late-stage tumors. Among the Cas-Br-E-induced non-T-, non-B-cell leukemias, viral integrations were found in the Fli-1 and Evi-1 region in 71% (36 out of 51) and 22% (16 out of 72) of the tumors analyzed, respectively. As an approach to evaluate the contribution of Cas-Br-E MCF recombinant formation in cis-activation of proto-oncogenes, we analyzed the structure of the Fli-1- and Evi-1-associated proviruses by Southern blot hybridization. In Fli-1, we found that the proviruses, ecotropic as well as MCF, are all integrated within a very short DNA region immediately upstream of the initiator ATG, toward the 3' end of a 5' exon (Ben-David, Giddens, Letwin, and Bernstein, 1991, Genes Dev. 5, 908-918). All proviruses are oriented the same way, in the 5' to 3' transcriptional sense. Both provirus types are able to direct the Fli-1 expression to the same extent presumably via a promoter insertion mechanism. Most of the proviruses had no detectable deletion and contained both 5' and 3' LTR sequences with similar U3 sequences. MCF recombinants did not show any selective advantage over ecotropic proviruses for the Fli-1 locus since the frequency of ecotropic to MCF-recombinant virus at the Fli-1 locus was identical to that observed at any other locus. This suggests that the formation of these MCF recombinants is not essential for activation of Fli-1 and that ecotropic Cas-Br-E already possesses the required sequences for full cis-activation of Fli-1. On the other hand, in Evi-1, there is a strict selection for ecotropic proviruses. Presumably, viral genetic elements outside of the U3 region could be critical for the Evi-1 cis-activation.

Determinants of thymotropism in Kaplan radiation leukemia virus and nucleotide sequence of its envelope region

Radiation leukemia viruses (RadLVs) are a group of murine leukemia viruses which are induced by radiation and cause T-cell leukemia. Viral clones isolated from the BL/VL3 lymphoid cell line derived from a thymoma show variable tropism and leukemogenic potential. We have constructed chimeric viruses by in vitro recombination between two viruses, a RadLV that is thymotropic and an endogenous ecotropic virus that is nonthymotropic. We show here that, in contrast to thymotropism determinants identified previously, which lie in the long terminal repeat (LTR), it is the envelope region that is responsible for the thymotropism of BL/VL3 RadLV. The nonthymotropic virus which we have rendered thymotropic by transfer of the env region of RadLV in the present study has been shown previously to become thymotropic when the LTR of another thymotropic virus is inserted in its genome. Thus, the LTR and envelope gene may be involved in complementary action to lead to thymotropism.

Low-grade myxoid chondrosarcoma of the base of the skull: CT, MR, and histopathology

A retrospective CT, MR, and histopathologic study was performed in five patients with histologically verified low-grade myxoid chondrosarcoma of the base of the skull. In four patients, the tumor originated off the midline and was associated with bone destruction at the petrous apex near the petrooccipital fissure. Tumor extent included the cerebellopontine angle in three patients and the parasellar area in two patients. The fifth tumor originated on the midline and was associated with destruction at the dorsum sellae. Three tumors contained calcifications, whereas two lesions were mostly isodense with brain on CT scan. All tumors were hypointense on T1-weighted MR images and very intense on T2-weighted images except for areas of signal void consistent with calcifications. Light microscopy revealed islands of mature hyaline cartilage in an abundant myxoid ground substance. Histology and immunocytochemical analysis were consistent with a low-grade myxoid chondrosarcoma. The CT and MR features of low-grade myxoid chondrosarcoma are comparable with those of chordoma. Chordoma usually arises from the midline, but cases with origin from the lateral portion of the clivus or the petrous apex have been described. Low-grade myxoid chondrosarcoma has distinct histologic and immunocytochemical features and includes lesions formerly called "chondroid chordomas."

The human homolog of the mouse common viral integration region, FLI1, maps to 11q23-q24

FLI1 is a common mouse viral integration region in virus-induced leukemias and lymphomas. Using an evolutionarily conserved mouse probe and Southern hybridization to (rodent x human) somatic cell hybrid DNAs, the human homolog of FLI1 has been shown to lie on a fragment of chromosome 11 flanked on the centromeric side by the acute lymphoblastic leukemia-associated t(4;11)(q21;q23) translocation breakpoint and on the telomeric side by the Ewing- and neuroepithelioma-associated t(11;22) (q24;q12) breakpoint.

High-yield method for directional cDNA library construction

Improvement of a cDNA synthesis procedure using a single stranded (ss) vector primer [Bellemare et al., Gene 52 (1987) 11-19] is reported. This vector (pPBS27), upon linearization with XbaI using an appropriate restriction site-directed fragment, releases a thymidilic tail used to prime cDNA synthesis. DNA polymerase I and RNase H replace the RNA strand and replicate the vector before double-stranded (ds) blunt-end ligation with T4 DNA ligase. More than 10(7) cfu/microgram of vector can be obtained with an efficient transformation protocol using either globin-encoding or 7.5-kb poly(A)-tailed RNA. This improved cloning method is easier, faster and a few hundred times more efficient than the original procedure as it involves ds rather than ss DNA for transformation.

Identification of a common viral integration region in Cas-Br-E murine leukemia virus-induced non-T-, non-B-cell lymphomas

The Cas-Br-E murine leukemia virus is a nondefective retrovirus that induces non-T-, non-B-cell lymphomas in susceptible NIH/Swiss mice. By using a DNA probe derived from Cas-Br-E provirus-flanking sequences, we identified a DNA region, originally called Sic-1, rearranged in 16 of 24 tumors analyzed (67%). All proviruses were integrated in a DNA segment smaller than 100 bp and were in the same 5'-to-3' orientation. Ecotropic as well as mink cell focus-forming virus types were found integrated in that specific DNA region. On the basis of Southern blot analysis of somatic cell hybrids and progeny of an interspecies backcross, the Sic-1 region was localized on mouse chromosome 9 near the previously described proto-oncogenes or common viral integration sites: Ets-1, Cbl-2, Tpl-1, and Fli-1. Restriction map analysis shows that this region is identical to the Fli-1 locus identified in Friend murine leukemia virus-induced erythroleukemia cell lines and thus may contain sequences also responsible for the development of mouse non-T-, non-B-cell lymphomas.

[A new space for feminine desire]

Psychoanalitical literature evolved around the idea of a space for desire structured according to the boy-mother relationship model. Is the feminine clinical approach, together with the historical contribution of feminism, discovering a new space for feminine desire? The psychotic female, for whom the role of the father has no meaning in the mother's discourse, refuses the Law as a symbol of social authority. As for the hysteric female, she does not rely on the Father as a safeguard against the emptyness that lies behind the Laws and the beliefs of men. In its own way, feminism adopts these positions of psychotic rejection and hysteric contestation by projecting them on to the social landscape. Furthermore, feminism requires new forms of social interaction that embody the esthetical space women need to experience life as full-fledged citizens.

Cystic schwannoma of the brainstem

A rare case of cystic schwannoma occurring in the brainstem in the absence of von Recklinghausen's disease is reported. This appears to be the first case in the literature of a cystic schwannoma ever described in this location. While the exact origin of this tumor in this unusual location remains uncertain, different hypotheses are discussed and the possible origin of this tumor from perivascular elements in the brainstem is seriously considered.

Imaging the pneumoconioses: a multidisciplinary approach

The initial early reaction of pulmonary tissue to inorganic dust inhalation is a fibrosing macrophagic alveolitis. This initial pulmonary lesion can be detected by an enhanced gallium 67 pulmonary uptake and analyses of bronchoalveolar lavage. These two techniques can document not only the increased proliferation of macrophages, but also the activation of macrophages to produce excessive amounts of fibronectin and other factors of fibroblastic growth implicated in the pathogenesis of the pneumoconioses. Of equal clinical interest is the development of computed tomography, which has permitted better characterization of the early stages of fibrosis in the pneumoconioses. These refinements in disease recognition will contribute to the earlier detection of pneumoconioses before they become incapacitating. Newer therapeutic methods are also under investigation that could permit inactivation of either the dust itself or the pulmonary macrophage. The coupling of these new diagnostic and therapeutic developments will bring in a new era in occupational pulmonary medicine.

Lung function in silica-exposed workers. A relationship to disease severity assessed by CT scan

To investigate the relationship of lung function, airflow limitation, and lung injury in silica-exposed workers, we analyzed the clinical, functional, and radiologic data of 94 long-term workers exposed in the granite industry or in foundries. The subjects were divided into four subsets based on chest roentgenogram and CT scan of the thorax: group 1 consisted of 21 subjects with category 0 chest roentgenogram and category 0 CT scan; group 2, 28 subjects with category E 1 on both chest roentgenogram and CT scan; group 3, 18 subjects with category E 1 on chest roentgenogram but with coalescence or conglomeration or both seen only on CT scan; and group 4, 27 subjects with category E 1 and coalescence or conglomeration or both on roentgenogram and CT scan. The groups did not differ in terms of age, height, cigarette smoking, or years of exposure. Lung volumes were significantly reduced only in group 4 (p less than 0.05). Lung compliance, diffusion capacity, and the rest-exercise P(A-a)O2 gradient were reduced in groups 3 and 4 (p less than 0.05). Expiratory flow rates were significantly reduced in groups 2, 3, and 4, with the lowest values in group 4. The expiratory flow rates in group 3 were significantly lower in group 3 than in group 2. These results support the concept that airflow in silica-exposed workers is significantly reduced when the disease is detectable on simple chest roentgenogram; coalescence or conglomeration or both on chest roentgenogram or CT scan is associated with significant loss of lung volumes, gas exchange function, and increased airflow obstruction.

CT assessment of silicosis in exposed workers

For evaluation of the clinical usefulness of CT of the thorax in workers exposed to silica, 58 workers with long-term exposure to silica in the granite and foundry industries of the Eastern Townships of Quebec were examined. CT scans were compared with standard posteroanterior chest radiographs by using the International Labour Office 1980 grading system for silicosis. Six areas of the lung in each patient were assessed by both techniques for profusion (number) of opacities (small nodules), coalescence, and the presence of large opacities. CT scans and chest radiographs yielded similar average scores for detection of opacities. CT identified significantly more coalescence and large opacities in patients with simple silicosis. In patients with complicated silicosis, CT results were comparable with those of chest radiographs. CT of the thorax in workers exposed to silica does not identify more patients with minimal parenchymal disease, but it does detect earlier changes of coalescence.

[For a new clinical approach to psychosis : the " 388 "]

The history of the last thirty years of North-American psychiatry points up the difficulties encountered in the treatment of psychotic patients in a hospital setting but also in the maintaining of their social integration. In a search for solutions, and taking into account the needs observed at the Robert-Giffard Hospital in Quebec, a group of professionals of GIFRIC decided to open, in the center of town, a Psychoanalytical Center for psychotics. Operating since 1982, the "388" is arming at a social réintégration of the psychotic patients in order to read a more satisfying life according to their possibilities of co-existence with others. It is an outside of the hospital structure which permits the treatment of the crisis as well as providing longterm care. The care and services given are based on a psychoanalytical frame. This paper describes the clientele, the services offered, the treatment, the patients' evolution and the problems that arise from the evaluation of such a new structure.

Computerized arthrotomography in recurring shoulder dislocations and subluxations

A prospective study of 14 patients demonstrated the value of computerized arthrotomography in the unstable shoulder. This technique allows the visualization of soft-tissue and bone anomalies that cannot be detected otherwise.

Radiographic assessment of pleuropulmonary disease in asbestos workers: posteroanterior, four view films, and computed tomograms of the thorax

To study the clinical usefulness of computed tomography (CT) scanning of the thorax in asbestos related pleuropulmonary disease, 127 long term asbestos workers of the mines and mills in the Eastern Townships of Québec were examined. The CT scan was compared with the standard posteroanterior (PA) chest film and the four view films using the ILO grading system for profusion of disease. Six lung areas and six pleural sites were studied. On the basis of the usual diagnostic criteria, 41% of the workers had asbestosis. For profusion of parenchymal disease, there was an excellent correlation (r = 0.96, p less than 0.001) between PA and four view films and the latter did not significantly increase the total profusion score; the CT scan correlated less well with the PA film (r = 0.79, p less than 0.01) and the scatter of the data was larger. In 10 of the 53 (19%) workers with asbestosis the pulmonary lesions were not recognised by CT scan. For profusion of pleural plaques, there was an excellent correlation (p = 0.91, p less than 0.001) between PA and four view films; scores were identical in 73%, higher for PA in 7%, and higher for four view films in 19%. CT scan scores, however, were identical with PA films in 31%, higher for CT scan in 13% (owing to higher scores on lateral pleural sites), and lower for CT scan in 56% (owing to lower scores at diaphragm and costophrenic angle sites). Pleural calcifications were identified in 24 workers for a total of 40 sites; 13 as possible, 31% identified by two modes, and 27 as definite. Of the latter, 14 were seen only on CT scan. In the workers with rigid pressure volume curve of the lung and increased Gallium-67 lung uptake only, CT scan total scores were not significantly higher than in those without these markers of early interstitial lung disease (5 +/- 1 v 4 +/- 1, p less than 0.05). Thus the four view films and CT scan appear to be useful mainly in the assessment of pleural disease. The four view film identifies more sites of pleural plaques and the CT scan more pleural calcified plaques.

Assessment of the unstable shoulder by computed arthrography. A preliminary report

The evaluation of 10 patients with subluxing and dislocating shoulder is presented. Routine radiography with special views detected the presence of Hill Sachs lesions in seven patients, but was not conclusive for three patients. Soft tissue and bone anomalies were documented by computed arthrography in all 10 patients. Computed arthrography represents a valuable tool in the diagnosis of obscure unstable shoulders.