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Biomedical subjects

Y Caspi

Publications and source records attributed to Y Caspi.

14 recordsLinked to original sources
PubMed2005

Space-time super-resolution.

We propose a method for constructing a video sequence of high space-time resolution by combining information from multiple low-resolution video sequences of the same dynamic scene. Super-resolution is performed simultaneously in time and in space. By "temporal super-resolution," we mean recovering rapid dynamic events that occur faster than regular frame-rate. Such dynamic events are not visible (or else are observed incorrectly) in any of the input sequences, even if these are played in "slow-motion." The spatial and temporal dimensions are very different in nature, yet are interrelated. This leads to interesting visual trade-offs in time and space and to new video applications. These include: 1) treatment of spatial artifacts (e.g., motion-blur) by increasing the temporal resolution and 2) combination of input sequences of different space-time resolutions (e.g., NTSC, PAL, and even high quality still images) to generate a high quality video sequence. We further analyze and compare characteristics of temporal super-resolution to those of spatial super-resolution. These include: How many video cameras are needed to obtain increased resolution? What is the upper bound on resolution improvement via super-resolution? What is the temporal analogue to the spatial "ringing" effect?

Algorithms↗
PubMed2000

Secondary V(D)J rearrangements and B cell receptor-mediated down-regulation of recombination activating gene-2 expression in a murine B cell line.

It has recently become clear that recombination of Ig genes is not restricted to B cell precursors but that secondary rearrangements can also occur under certain conditions in phenotypically immature bone marrow and peripheral B cells. However, the nature of these cells and the regulation of secondary V(D)J recombination in response to B cell receptor (BCR) stimulation remain controversial. In the present study, we have analyzed secondary light chain gene rearrangements and recombination activating gene (RAG) expression in the surface IgM+, IgD- murine B cell line, 38C-13, which has previously been found to undergo kappa light chain replacement. We find that 38C-13 cells undergo spontaneous secondary Vkappa-Jkappa and RS rearrangements in culture, with recombination occurring on both productive and nonproductive alleles. Both 38C-13 cells and the Id-negative variants express the RAG genes, indicating that the presence of RAG does not depend on activation via the 38C-13 BCR. Moreover, BCR cross-linking in 38C-13 cells leads to a rapid and reversible down-regulation of RAG2 mRNA. Therefore, 38C-13 cells resemble peripheral IgM+, IgD- B cells undergoing light chain gene rearrangement and provide a possible in vitro model for studying peripheral V(D)J recombination.

Animals↗
PubMed2000

Detoxification centers: who's in the revolving door?

Data from 443,812 admissions to publicly funded detoxification centers in Massachusetts (fiscal year 1984 to fiscal year 1996) were analyzed to assess changes in the population served. Substantial increases in admissions of women, African Americans, and Hispanics were apparent. Mean age at admission declined and unemployment increased. A 25% decline in admissions reporting alcohol use was coupled with a twofold increase in reported cocaine use and a fourfold increase in heroin use. Detoxification services have evolved. The older, white, male alcoholic is no longer the primary consumer. Policy initiatives (e.g., increased services for women) and the changing epidemiology of drugs abuse (e.g., increased access to heroin) contributed to the changing population served in detoxification centers.

Adult↗
PubMed1998

Relationship of child loss to psychiatric and functional impairment in resettled Cambodian refugees.

One hundred sixty eight respondents, recruited from a community of resettled Cambodian refugees in Massachusetts, were interviewed for a study of trauma, physical and emotional health, and functioning. Of the 161 respondents who have ever had any children, 70 parents (43%) reported the death of between one and six of their children. Child loss was positively associated with health-related concerns, a variety of somatic symptoms, and culture-bound conditions of emotional distress. No relationship was found with conventional psychiatric symptoms of depression and posttraumatic stress disorder. Parents whose children died were performing most routine daily activities and participating in social activities to a similar and even greater extent than were parents who did not lose children. Nevertheless, child loss was strongly associated with a perception of health-related limitation in both physical functioning and social activities. Further research on the prevalence of child loss and its impact on long-term adjustment in survivors of mass trauma is indicated.

Adult↗
PubMed1995

Light chain loss and reexpression leads to idiotype switch. Surrogate light chains are probably responsible for this process.

The murine B-lymphocyte cell line 38C-13 is characterized by several cell surface markers typical for an early stage of B-cell differentiation. Cells of this cell line possess cell surface membrane IgM molecules composed of mu and kappa polypeptide chains. They also produce "surrogate" or "pseudo" light chains (psi L) coded by the lambda 5 and VpreB genes. Variants of the 38C-13 cell line which do not synthesize kappa chains can be isolated from the 38C-13 population by the use of anti-idiotype antibodies in vivo and in vitro. In some kappa chain-deficient variant cell lines, cells which have regained surface IgM expression but have lost the original idiotype specificity, can be isolated. This idiotype switch is probably due to a secondary rearrangement of the kappa gene. In the kappa chain-deficient variant cells, the mu chains assemble with the surrogate light chains but the assembled IgM-like molecules are not expressed on the cell surface. It is suggested that surrogate light chains play an important role in the induction of kappa gene rearrangement but that surface expression of mu-psi L complexes is not required for this process.

Animals↗
PubMed1995

The effects of passive anti-viral immunotherapy in AKR mice: II. Susceptibility to B cell lymphomagenesis.

Prevention of high frequency spontaneous T cell lymphoma development in AKR mice by mAb 18-5 treatment was shown to involve inhibition of the recombinant Class I MCF virus formation and elimination of the early occurring potential lymphoma cells (PLCs). A low B cell lymphoma incidence (16% at a mean latency of 540 days) and a low level of PLCs (yielding 12% B cell lymphoma development following lymphoid cell transfer) was observed in mAb 18-5 treated mice (in contrast to a high PLC level in thymectomized AKR mice that could be experimentally triggered to progress to overt CD5+ B cell lymphomas). Administration of anti CD8 mAb or IL-4 to 12-month-old mAb 18-5 pre-treated mice only slightly increased B cell lymphoma incidence (up to 30-40%). Exposure to split-dose irradiation resulted in 26% B cell lymphomas at a 250 day mean latency. The phenotypes of the B lymphomas developing in mAb 18-5 treated mice were: B220+ (14.8+, 6B2+), 6C3+, Mac2+, CD5-. Most lymphomas expressed l-a and surface IgM, pointing to their mature B cell characteristics. Moreover, in some of the lymphomas, high levels of IgM production and secretion were determined. A comparison of the morphological characteristics (based on light and ultrastructure microscopy) of CD5+ and CD5- B cell lymphomas developing in AKR mice indicated marked differences. Analysis of the IgH locus of representative CD5- B lymphomas showed an identical pattern of IgH rearrangement in some tumors (similar to previous findings among CD5+ lymphomas). The virological analysis of the CD5- B cell lymphomas (similar to those observed in the CD5+ B cell lymphomas of AKR origin) showed that their development did not require formation of the pathogenic MCF recombinant viruses. The differences observed between the CD5+ and CD5- B cell lymphomas developing in AKR mice (following prevention of spontaneous T cell lymphomagenesis) may be due to their origin of different B cell precursors or from B cells at different levels of differentiation.

Animals↗
PubMed1989

[Annulo-aortic ectasia].

Aortic regurgitation due to annular aortic ectasia was diagnosed in a 29-year-old woman with heart failure. The primary pathology of this disease is cystic medial necrosis of the ascending aorta with aneurysm formation and dilation of the aortic valve annulus. In successful surgical correction, the ascending aorta was replaced by a dacron prosthesis, the aortic valve by a prosthetic disc valve and the coronary arteries were reimplanted into the aortic graft.

Adult↗
PubMed1987

The significance of bundle branch block in the immediate postoperative electrocardiograms of patients undergoing coronary artery bypass.

Three hundred sixteen consecutive patients undergoing coronary artery bypass were studied for postoperative electrocardiographic conduction disturbances. Fifty-five of these 316 patients had postoperative bundle branch block (Group 1). This group had a higher incidence of left main coronary stenosis, together with previous inferior myocardial infarction, than patients without postoperative conduction disturbances (Group 2). Perioperative myocardial infarction, low cardiac output, and death were significantly more common in Group 1 than in Group 2: 7.3% versus 1.9% for perioperative myocardial infarction, 16.4% versus 2.7% for low cardiac output, and 5.5% versus 0.8% for death. Analysis of the type of conduction disturbances indicates that the presence of a new complete left bundle branch block postoperatively in a patient undergoing coronary artery bypass is a sign of intraoperative myocardial damage. This damage is potentially lethal, especially in a patient with left main coronary stenosis and previous inferior myocardial infarction.

Bundle-Branch Block↗
PubMed1985

Rupture of splenic abscess through the diaphragm.

Splenic abscess is an uncommon disease that has a high mortality rate if not treated surgically. With the aid of new diagnostic tools, such as ultrasonography, scanning and computerized axial tomography, it is possible to diagnose the entity antemortem. Even though it often has a nontypical clinical course, it may overlap other systemic diseases. We describe an unusual case of splenic abscess with rare complications, the operation and the outcome.

Abscess↗
PubMed1985

Successful repair of concomitant tear of the interventricular septum and right ventricular free wall after acute myocardial infarction.

Early repair of acute rupture of the ventricular septum after myocardial infarction is now the procedure of choice accepted by most centers. Rupture of the right ventricular free wall is rare and usually is accompanied by tamponade. The finding of coincidental right ventricular free wall rupture and acute ventricular septal defect following myocardial infarction and their successful repair are discussed in the following report.

Aged↗
PubMedDate not supplied

Surgical treatment of post-infarction ventricular septal defect without concomitant myocardial revascularization.

Twenty one patients suffering from rupture of the ventricular septum (RVS) following acute myocardial infarction were operated upon between 1982-1985. Eighteen patients were operated upon urgently within 9.3 +/- 2.1 hours following diagnosis of RVS. In all, RVS occurred during the first infarction. None had concomitant myocardial revascularization. There were twelve operative survivors for an operative mortality of 42.5%. Two patients died 6 and 9 months postoperatively. All survivors are in functional class I, during a follow-up period of 14 to 56 months. The need for urgent repair of RVS is stressed and the value of concomitant coronary artery bypass is discussed.

Aged↗