Development and mapping of 2240 new SSR markers for rice (Oryza sativa L.) (supplement).
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Chromosome Mapping↗
Biomedical subjects
David Schneider
Publications and source records attributed to David Schneider.
Articular cartilage reconstruction using xenogeneic epiphyses slices.
Reconstruction of articular cartilage defects using adult osteochondral allografts is an established clinical procedure, whose principal drawback is lack of lateral integration of the grafts to the surrounding tissue. Autologous chondrocytes transplantation is a sophisticated technique requiring cell culture and a staged operation. Its main draw back is the lack of mechanical strength early on. This study was conducted in order to evaluate the possibility of using embryonal epiphyses as a cartilage reconstruction tissue. A xenogeneic human to rabbit sub-acute osteochondral defect model was designed to evaluate the possibility of allogeneic implantation in humans. The following procedures were perfomed (n = 5): transplantation of 1. live epiphyses 2. live epiphyses with autogeneic periosteum 3. de-vitalized epiphyses and 4. devitalized epiphyses with autogeneic articular chondrocytes. A fifth control group did not receive any implant. Animals in groups 1 and 2 had a viable reconstruction of the articular surface with little evidence of rejection and without pannus formation. Animals in groups 3 and 4 became severely arthritic and the graft was resorbed. Nitric oxide synthase accumulation was reduced in group 1 and 2 as compared to groups 3, 4, and 5, indicating a joint preserving function of the epiphyseal grafts. Epiphyseal grafts appear to be a feasible procedure for reconstruction of articular cartilage defects even in a xenogeneic model.
Journal Article↗
Fetal survival in the rat as affected by intrauterine injection of serum containing antiphospholipid antibodies.
PROBLEM: We wanted to study and examine whether the detrimental effect of antiphospholipid antibodies on gestation is locally derived. Therefore, we established an experimental rat model, enabling to study the intrauterine effect of serum, containing antiphospholipid antibodies, in vivo. METHODS: Sera were obtained from five women, having anticardiolipin antibody and lupus anticoagulant, and presenting with antiphospholipid antibody syndrome. Pooled serum of 150 microL was injected into unilateral uterine horn of each rat on days L2-L7 of rat pregnancy. The contralateral uterine horn was used for injection of 150 microL normal serum or physiologic saline as a control. The rats were sacrificed on day L14, and the uterus of each rat was inspected for the presence of live and resorbed fetuses. RESULTS: A significant effect on fetal resorption and viability was observed following the intrauterine injection of antiphospholipid positive serum (APL positive serum), as compared with the intrauterine injection of normal serum or saline. A significant increase in fetal resorption rate and decrease in fetal viability was noted following the injection of APL positive serum on day L6 (P = 0.005 and 0.004, respectively) and day L7 (P = 0.003 and 0.003, respectively) as compared with normal serum. A comparison with the contralateral injection of saline demonstrated a significant effect of the APL positive serum also following the intrauterine injection on days L3 and L5. CONCLUSIONS: The current study provides an experimental rat model, which can be employed to study the local intrauterine effect of APL positive serum on pregnancy outcome and to further assess the efficacy of various treatment modalities.
Animals↗
Pharmacological properties of nicotinic acetylcholine receptors expressed by guinea pig small intestinal myenteric neurons.
The electrophysiological and pharmacological properties of nicotinic acetylcholine receptors (nAChRs) were studied in guinea pig small intestinal myenteric neurons maintained in culture or in acutely isolated preparations. Acetylcholine and nicotine caused inward currents that desensitized in approximately 4 s. The current-voltage (I-V) relationship rectified inwardly with a reversal potential near 0 mV. The agonist rank order potency was 1,1-dimethyl-4-phenyl-piperazinium > acetylcholine = nicotine >> cytisine. Agonist-induced currents were blocked by nAChR antagonists with a rank order potency of mecamylamine > hexamethonium > dihydro-beta-erythroidine (DHbetaE); mecamylamine and DHbetaE exhibit high potency at beta4 and beta2 subunit-containing nAChRs, respectively. alpha-Bungarotoxin (0.1 microM) or alpha-methyllycaconitine (0.1 microM), antagonists that block nAChRs containing alpha7 subunits, did not affect acetylcholine-induced responses. Immunohistochemical studies revealed that nearly every neuron in culture was labeled by an antibody (mAb35) that recognizes nAChR alpha3 and alpha5 subunits. Antibodies selective for alpha3, alpha5, or beta2 subunits also stained most neurons, whereas an alpha7 subunit antibody revealed very few neurons. In neurons in the intact myenteric plexus from newborn and adult guinea pigs, local application of acetylcholine (1 mM) and cytisine (1 mM) caused similar amplitude depolarizations, and these responses were blocked by nAChR antagonists with a rank order potency of mecamylamine > hexamethonium > DHbetaE. These data indicate that myenteric neurons maintained in culture predominantly express nAChRs composed of alpha3, alpha5, beta2, and beta4 subunits. These subunits may be in a homogeneous population of receptors with unique pharmacological properties, or multiple receptors of different subunit composition may be expressed by individual neurons.
Algorithms↗
The doctor is out: physician participation in the Rationed Access Day work stoppage in British Columbia, 1998/99.
BACKGROUND: In 1998/99, the British Columbia Medical Association (BCMA) asked physicians to withdraw elective services on a series of 20 Rationed Access Days (RADs). This work stoppage was called to protest continued free proration triggered by total physician billings exceeding a fixed budget cap. This paper examines how physicians' practice activity changed on RADs, the rates of participation in this job action and characteristics of those physicians who participated. DESIGN: Population-based cohort study of physicians based on administrative data. POPULATION: All full-time physicians billing the provincial healthcare plan. METHODS: Participation in the RAD initiative was inferred by comparing physicians' average daily billings on RADs, Sundays, holidays and regular weekdays. Using thresholds established from these distributions, the number of RADs observed by each physician in 1998/99 was calculated and examined in relation to their demographics, location and prior years of practice activity. RESULTS: For the 4,131 physicians studied, average daily payments on RADs were similar to those on Sundays and holidays but much lower than those on non-holiday, non-RAD weekdays. Using billing thresholds of $200 (for GPs) and $400 (for specialists), we found a high degree of participation with the study population observing a median of 15 of the 20 scheduled RADs. While there were some differences in participation among age groups, geography and the prior years of practice activity, the differences were small. INTERPRETATION: This study found high solidarity in the BCMA's 1998/99 RAD initiative. Most full-time fee-for-service FS physicians appeared to participate in at least three-quarters of the 20 scheduled RADs.
British Columbia↗
The role of lymphocytes and macrophages in human breast tumorigenesis: an immunohistochemical and morphometric study.
The objective of the present study was to analyze the function of lymphoid elements in the tumorigenesis of human breast cancer, similar to their elucidation in human ovarian cancer in our previous work. The lymphocytic and macrophageal content of lymphocytes and macrophages was analyzed immunohistochemically and morphometrically in 49 human breast tumors of different types. The following types of tumors were studied: 1) fibrocystic disease, 2) fibroadenoma, 3) carcinoma in situ, 4) infiltrating ductal and lobular carcinoma with high lymphoid infiltration, and 5) infiltrating ductal and lobular carcinoma with lymphoid depletion. The first two had little lymphoid infiltration and few lymphocytes (mainly T cells), while carcinoma in situ had extensive lymphoid infiltration and increased lymphocytic density, the consequence of a sharp rise in total lymphocytes reflecting the intensified immune response. In ductal and lobular infiltrating carcinoma with high infiltration, T cells were in large excess of B cells (81% and 87% vs. 11%) and CD8+ lymphocytes were the predominant type of T cells (up to 90%), in both tumoral parenchyma and stroma. In infiltrating carcinoma with lymphoid depletion, the total lymphocyte and macrophage count and areas of lymphoid infiltrates decreased, relative to highly infiltrated carcinomas, as signs of deep subcompensation of the lymphoid system. The host's reaction to disease was reflected in high correlations between the densities of the lymphoid cellular elements as tumorigenesis evolved. We suggest that the stromal immunocompetent cells are a reservoir of T killers that eventually cross into the parenchyma and join T helpers and B lymphocytes in the immune antitumor response. In later stages of cancer the response is exhausted, as manifested in lymphoid subcompensation.
Breast Neoplasms↗
Diagnostic hysteroscopy as a primary tool in a basic infertility workup.
OBJECTIVE: To assess the value of diagnostic hysteroscopy in a primary workup of infertility. METHODS: We performed a retrospective analysis (Canadian Task Force Classification II-2) of 221 infertile patients referred to the Outpatient Center for Uterine Cavity Evaluation and the Tel-Aviv University affiliated Assaf Harofe Medical Center for evaluation of the uterine cavity. Patients underwent a diagnostic office hysteroscopy. RESULTS: Hysteroscopy revealed an abnormal uterine cavity in 30% of women evaluated for either primary or secondary infertility. No significance was found regarding the total number of intrauterine pathologies when comparing the groups of primary versus secondary infertility. CONCLUSION: Routine diagnostic hysteroscopy should be part of an infertility workup in primary and secondary infertility.
Adolescent↗