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Biomedical subjects

S Rosenthal

Publications and source records attributed to S Rosenthal.

At least 19 recordsLinked to original sources
PubMed1992

Computer methods in quantitation of cardiac wall parameters from two dimensional echocardiograms: a survey.

With increasing use of two-dimensional echocardiograms (2DE) for diagnosis [1, 2], efforts to computerize the process of quantification of cardiac parameters have increased. Visual processing of echocardiograms is time and labor intensive, and usually provides qualitative results with subjective variations [3]. In contrast, computer assisted methods are efficient and provide quantitative reproducible results. On the basis of the extent of computer usage, the 2DE processing methods are classified into three categories, namely, manual [9-30], interactive [32-49], and automatic methods [51-82]. This work is a structured survey of the published research on these three categories.

Echocardiography↗
PubMed1992

Progestin regulation of insulin and insulin-like growth factor I receptors in cultured human breast cancer cells.

Recent studies indicate that the insulin receptor (IR) content is higher in breast cancer cells than in normal mammary epithelial cells. This observation has been made both in tissue specimens from patients with breast cancer, and in various human cultured breast cancer cell lines. Investigations have now been undertaken to understand the role of progestins in the regulation of the IR and the closely related insulin like growth factors-I receptor (IGF-I-R). Pretreatment of T-47D cultured human breast cancer cell lines with progestins induced a time and dose dependent increase in IR content. This increase was due primarily to an effect of progestins to increase IR mRNA levels. Other steroid hormones including glucocortocoids, estrogen, and testosterone were without effect. In contrast to their up-regulation of the IR, progestins down-regulated the IGF-I-R at the level of mRNA. An analysis of the processes involved revealed that progestins increased the biosynthesis of a ligand for IGF-I receptor, IGF-II. IGF-II in turn down-regulated the IGF-I-R. Thus these studies indicate that progestins have important effects on both the IR and the IGF-I-R. The effects of progestins on these and other growth factor receptors, therefore, may have an important role in the biology of breast cancers.

Breast Neoplasms↗
PubMed1992

Kinetics of diffusion in a spherical cell. I. No solute buffering.

Realistic neuron models that involve effects of concentration changes of second messengers on ion channels must include processes such as diffusion and solute buffering. These processes, which span a wide range of spatial and temporal scales, may impose a severe computational burden. In this paper and its companion, we examine the kinetics of diffusion and present methods for stimulating it accurately and efficiency. The problem of calcium diffusion in a spherical cell is used as a device to demonstrate the practical application of our analysis. However, the scope of these papers is not limited to this problem. The same analysis that we apply and concerns that we raise are germane to the spread of any second messenger, and can be adapted to other geometries. The focus of this paper is the simplest case: diffusion in the absence of solute buffering. This analysis also applies whenever buffering is so fast that it is instantaneous compared to diffusion, or so slow that concentration gradients have dissipated before substantial buffering takes place. The second paper investigates the more difficult situation where diffusion and buffering occur at comparable rates. In the absence of buffering, concentration changes produced by diffusion can be fit by an infinite series of exponential terms. We show how to design a model with N + 1 compartments that fits the N slowest terms of this series exactly in a shell just inside the cell membrane.

Animals↗
PubMed1992

Kinetics of diffusion in a spherical cell. II. Solute buffering included.

This paper on diffusion kinetics in neurons presents an analysis of diffusion in the presence of solute buffering. Computational rather than theoretical methods are usually necessary since buffering generally precludes an analytical solution to the diffusion equations. As in the companion paper, our methods are illustrated in the context of calcium diffusion in a spherical cell. However, the same methods can be applied to the spread of any second messenger and other geometries. Analytical or computational predictions of the time course of diffusion and buffering may help guide further experiments and simulations. For example, simulations of calcium diffusion in a model of the bullfrog sympathetic ganglion cell show that buffering at depths greater than 5-6 microns is almost instantaneous compared to diffusion from sources at the cell membrane. Since buffering complicates the design of multicompartmental models, we demonstrate that a few compartments designed on the basis of diffusion alone (Carnevale and Rosenthal, 1992) may be a satisfactory framework for a model that includes bimolecular buffering. An analytical solution may be possible if the buffering reaction can be linearized. We describe a method for linearizing bimolecular saturating buffering, i.e., approximating it by a unimolecular non-saturating process that immobilizes solute. The analytical solution for the linearized reactive diffusion problem fits a non-linear model of calcium movement in the bullfrog sympathetic ganglion cell quite well after a few milliseconds.

Animals↗
PubMed1992

Comparing the effectiveness of behavioral treatment for chemotherapy-induced nausea and vomiting when administered by oncologists, oncology nurses, and clinical psychologists.

Adequate control of side effects during medical treatment of cancer increases patient compliance and quality of life. Antiemetic drugs are not an effective treatment for the one in three cancer patients on chemotherapy who experience anticipatory nausea and vomiting (ANV); the behavioral treatment of systematic desensitization has been found effective for ANV when delivered by clinical psychologists. This study examined the effectiveness of systematic desensitization when delivered by medical personnel versus clinical psychologists. Seventy-two consecutive cancer patients with ANV were randomly assigned to no-treatment control or to systematic desensitization from 5 behaviorally trained clinical psychologists, 6 clinical oncologists, or 10 oncology nurses. The treatment was found effective in reducing anticipatory nausea, anticipatory vomiting, posttreatment nausea, and posttreatment vomiting compared to control patients, with no significant differences in effectiveness found between clinical psychologists and oncology staff. Although medical personnel should not engage patients in psychotherapy or other interventions that cannot be completed successfully, they can treat patients effectively with systematic desensitization and should be encouraged to learn and use this and other behavioral intervention techniques to benefit total patient care.

Behavior Therapy↗
PubMed1992

Recurrence of hepatitis B and delta hepatitis after orthotopic liver transplantation.

The clinical course of 10 liver transplant recipients who had hepatitis B virus (HBV) and five recipients with HBV and D (delta) infection before transplantation is described. Six patients who underwent eight transplants died. The estimated one and two year survival rates in patients with HBV only before transplantation were 74% and 67% respectively. The estimated one and two year survival in patients with HBV and HDV infection beforehand was 100%. Graft infection by HBV occurred in 8 of 10 patients infected with HBV only; and in 4 of 5 patients with previous HBV and HDV infection. There was a widely variable time from transplantation to the appearance of HBV markers in liver or serum, ranging from 6-331 days. Hepatitis D antigen (HDAg) appeared in three grafts very rapidly after transplantation at 4, 8, and 37 days respectively. Graft infection by HBV was accompanied by significant liver injury in six allografts in five recipients. In particular, there was a striking morphological appearance in five infected livers in which the hepatocytes became progressively enlarged and distorted as they accumulated huge amounts of hepatitis B surface and core antigens (HBsAg, HBcAg). These features were accompanied by pericellular fibrosis and cholestasis but little associated inflammation. This syndrome carried a poor prognosis. A gradual progression to cirrhosis occurred in one additional liver. Finally, recurrent HBV infection was a principal or a contributing factor in all deaths. The presence of HBcAg and inflammation in he native liver increased the risk of HBV induced tissue damaged in the graft whereas HDV infection in the host liver seemed to reduce the risk of significant HBV induced tissue damage in the allograft. These data suggest that post transplant HBV infection is accompanied by a variety of changes in the liver allograft, some of which are unique to the transplanted liver and may result in impaired allograft function.

Adolescent↗
PubMed1992

Gastrointestinal obstruction due to Mycobacterium avium intracellulare associated with the acquired immunodeficiency syndrome.

Three patients with the acquired immunodeficiency syndrome (AIDS) had complete or incomplete gastrointestinal obstruction resulting from infection with Mycobacterium avium intracellulare. The pathophysiologic mechanisms of the obstruction in the three cases were ileal volvulus due to adhesions from matted infected mesenteric lymph nodes, ileal intussusception due to engorged infected ileal mucosa, and small bowel displacement and compression by massively enlarged infected intraabdominal lymph nodes. These reports extend the clinical manifestations of Mycobacterium avium intracellulare infection in patients with AIDS to include partial and complete gastrointestinal obstruction.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Expression of bovine leukaemia virus antigens fused to MS2 polymerase in E. coli.

The main core protein and segments of envelope proteins of bovine leukaemia virus fused to MS2 polymerase were expressed in E. coli. The synthesis rate varied between 3 and 25% of the total cellular proteins. BLV-MS2 polymerase fusion proteins were detected immunologically using rabbit anti-BLV sera, monoclonal antibodies and a serum of a BLV-infected cow.

Antigens, Viral↗
PubMed1990

Insulin-like growth factor I (IGF-I) levels in follicular fluid from human preovulatory follicles: correlation with serum IGF-I levels.

Insulin-like growth factor I (IGF-I) levels were measured in both serum and fluid of preovulatory follicles (n = 156) in 43 women undergoing in vitro fertilization (IVF). The mean IGF-I level in follicular fluid (FF) was significantly lower than in serum (0.52 +/- 0.02 IU/L versus 0.66 +/- 0.23 IU/L), and FF levels were significantly correlated with individual serum IGF-I levels as well as with follicular size and FF volume but not with oocyte maturity, granulosa cell appearance, or IVF. This suggests that FF IGF-I levels cannot serve as a clinical indicator for the degree of oocyte/granulosa cell differentiation or a predictor for IVF. Serum IGF-I levels were inversely correlated with the number of human menopausal gonadotropin ampules administered during treatment, suggesting that IGF-I might enhance ovarian gonadotropic stimulation.

Estradiol↗
PubMed1990

A confocal video-rate laser-beam scanning reflected-light microscope with no moving parts.

A no-moving-parts, 30 frames/s, laser-beam scanning confocal reflected-light microscope has been developed. In principle, the technique can be extended to fluorescence and transmission light microscopy. Acousto-optic beam deflectors controlled by digital electronics move a laser beam in a 512-line interlaced 8.5 x 8.5-mm raster. The light passes through a beam splitter, enters an inverted microscope through the side camera port, and is imaged at the object by the microscope objective. Reflected light returns through the objective, exits the camera port, is reflected off the beam splitter, and is imaged on to the photocathode of an image dissector tube (IDT). Confocality is provided by raster scanning the IDT aperture coincident with the congruent image of the laser beam incident on the object. Real-time jitter-free reflected light images of a variety of biological objects have been produced. Computer-controlled alignment of the laser scan and IDT is performed in several seconds.

Animals↗
PubMed1990

Immunological characterization of BLV proteins synthesized in Escherichia coli.

Hybrid proteins composed of beta-galactosidase and polypeptides of the bovine leukaemia virus (BLV) including those of the main core protein p24, the envelope protein gp51 and the transmembrane protein gp30 were produced in Escherichia coli and immunologically characterized. The hybrid proteins were immunologically reactive with sera from cattle naturally infected with BLV, demonstrating a possible use for diagnosis of BLV infection. Detection of antibodies was most sensitive with the p24 derivative.

Animals↗
PubMed1990

Recombinants from a proviral bovine leukemia virus genome corresponding to the 3' region transactivate viral LTR in NIH3T3 and non-infected FLK cells.

Bovine leukemia virus (BLV), like human T-cell leukemia viruses, Types I and II, contains three open reading frames at the 3' end of its genome. The longest open reading frame encodes a transactivator protein which is generated by a doubly-spliced mRNA. A series of co-transfection experiments, using proviral BLV pX expression plasmids under the control of the Moloney leukemia virus LTR and the indicator plasmid containing the assayable lac Z gene under the control of BLV LTR, revealed that both NIH3T3 cells and non-infected fetal lamb kidney cells are able to express an active transactivator protein.

Animals↗
PubMed1990

Synthesis of bovine leukemia virus antigens in Escherichia coli.

Plasmids were constructed by the use of pEX vectors that encode and express different parts of the bovine leukemia virus (BLV): main core protein p24, nucleic acid-binding protein p12, transmembrane protein gp30, and different segments of envelope protein gp51. Expression of fusion proteins with molecular weights higher than 117 kD for all recombinant plasmids was shown in Coomassie-blue stained gels and by Western blot analysis with rabbit anti-BLV sera. Coupling of a gp51-encoding with a p24-encoding DNA fragment in pEX vectors led to synthesis of a fusion protein that was recognized by monoclonal antibodies directed against gp51 and p24 epitopes. Using another vector, a gp51-encoding DNA fragment of BLV was expressed as a fusion protein with 100 amino acids of the MS2 polymerase. The fusion protein was recognized by monoclonal antibodies directed against gp51.

Animals↗
PubMed1990

Use of monoclonal antibody against major internal protein p24 of bovine leukemia virus in capture ELISA.

A monoclonal antibody (4H4) against the major internal protein, p24, of bovine leukemia virus (BLV) is described. It recognizes a sequence determinant on the p24-molecule and displays high affinity to its antigen. The monoclonal antibody 4H4 was applied in capture ELISA for diagnosis of enzootic bovine leukosis, using crude BLV-preparation as antigen. This test is more sensitive than the immunodiffusion test and at least as sensitive as direct ELISA.

Animals↗
PubMed1990

New ELISA test for detection of bovine leukemia virus infections in cattle, using bacterially synthesized p24.

A new ELISA test is described for the detection of antibodies to bovine leukemia virus protein p24. This test employs a bacterially synthesized p24 antigen which represents a hybrid protein consisting of beta-galactosidase and about 70% of the mature viral p24. The antigen preparation was enriched from Escherichia coli cells to 95% purity and was used for the detection of antibodies in cattle. In a selected set of 100 positive field sera, 97 could be verified by the new test.

Animals↗