Localization of the conformational alteration of MHC molecules induced by the association of mouse class I heavy chain with a xenogeneic beta 2-microglobulin.

Changes in the antigenicity of major histocompatibility complex (MHC) class I molecules resulting from the association of bovine beta 2-microglobulin (beta 2-m) with mouse class I heavy chains were investigated. Mice (H-2b) were immunized with syngeneic Concanavalin A (Con A) blasts induced in the presence of fetal calf serum (FCS) in conditions allowing exchange between mouse and bovine beta 2-microglobulin (beta 2-m). Spleen cells from hyperimmunized mice were fused with myeloma cells and two monoclonal antibodies which required for their reactivity the presence of FCS have been further studied.

Regulation of the abscisic acid-responsive gene rab28 in maize viviparous mutants.

We have isolated a new maize gene, rab28, that responds to abscisic acid (ABA) treatment. This gene has been characterized by determining the sequence of the cDNA and corresponding genomic copy, and by mapping the start site of its transcript. The rab 28 gene encodes a protein of predicted molecular weight 27713 Da which shows strong homology with the Lea D-34 protein identified in cotton.

Analysis of primary HLA-specific cytotoxic T cell response in graft-draining lymph nodes--a transgenic mouse model for in vivo recognition of human MHC antigens.

In order to characterize primary anti-HLA cytotoxic T cells and especially those involved in graft rejection, we have utilized a transgenic mouse model. Mice (non-transgenic and HLA-transgenic) were grafted with spleen cells originating from H-2-matched transgenic mice expressing HLA-B27 molecules, and cells from graft-draining lymph nodes were tested in CML assay to investigate the primary in vivo induced CTL responses. The results showed that HLA-B27 molecules were able to raise strong primary xenogeneic CTL responses.

Fractionated stereotactic radiation therapy for intracranial tumors.

In stereotactic radio surgery, a single, large dose of radiation is delivered to a small, well-defined, stereotactically localized intracranial lesion. In contrast to conventional radiation therapy, in radio surgery no attempt is made to spare normal cells within the target volume by fractionating the tumor dose. In 1987, the authors began a program of fractionated stereotactic radiation therapy for selected tumors involving sensitive brain structures.

Regulation of the maize rab17 gene promoter in transgenic heterologous systems.

The maize rab17 gene is expressed in different plant parts in response to ABA and osmotic stress (J. Vilardell et al., Plant Mol Biol 14 (1990) 423-432).

Induction of ovulation in rabbits with pure urinary luteinizing hormone and human chorionic gonadotrophin: comparison of oocyte and embryo quality.

Thirty-six 18-week-old nulliparous does were stimulated with a single dose of 25 IU pregnant mare serum gonadotrophin (PMSG). Ovulation was induced 48 h later with 50 IU luteinizing hormone (LH) (18 does) or 50 IU human chorionic gonadotrophin (HCG) (18 does) in order to determine the effects of pure urinary LH and HCG on the quality of oocytes and embryos. Nine does were mated in each group.

H-2 influence on the production of real but not of apparent H-2-specific antibodies induced by the association of syngeneic class I heavy chains with bovine beta 2-microglobulin.

Immunogenic properties of class I molecules resulting from the association of mouse class I heavy chains with a xenogeneic beta 2-microglobulin (beta 2-m) were investigated by studying the antibody response of mice of injections to syngeneic Con A lymphoblasts, induced in conditions allowing the replacement of endogenous beta 2-m by exogenously added bovine beta 2-m provided by fetal calf serum (FCS-Con A blasts). Lymphocytotoxic antibodies were regularly produced and according to their specificities they could be divided into two types: antibodies whose reactivity was (1) dependent on and (2) independent of the presence of bovine beta 2-m on target cells. Although both types displayed an H-2 dependent polymorphic reaction pattern, only antibodies recognizing class I molecules without bovine beta 2-m can be considered as real H-2-specific antibodies.

Physical aspects of the angle-beta concept in electron arc therapy.

A technique for the determination of treatment parameters that are required to achieve a desired depth dose distribution in electron arc therapy is discussed and a method for calculating isodose distributions is presented. Both the treatment technique and the dose calculation method rely on the angle beta concept, which uniquely describes the dependence of the radial percentage depth doses in electron arc therapy on the nominal field width, isocenter depth, and virtual source-axis distance. The angle beta concept is discussed in detail and the electron pseudo-arc therapy technique used at McGill is described.

Recognition of HLA-B27 by mouse cytotoxic T-cell clones: a transgenic mouse model.

As a basis for the characterization of mouse T cells involved in the recognition of xenogeneic HLA molecules, a panel of HLA-B27-reactive cytotoxic T-cell clones was generated upon stimulation by cells from HLA-B27-transgenic mice. The HLA-B27-induced T-cell response was found to comprise two categories of clones: some recognizing HLA-B27 independent of H-2 molecules expressed by the target cells (unrestricted clones), others recognizing HLA-B27 in an H-2-restricted manner. The unrestricted clones exhibited diverse specificities, as judged from their various cross-reactivities with other xenogeneic (HLA) or allogeneic (H-2) molecules.

The SCID mouse.

Numerous investigations of the mammalian hematopoietic system in normal and pathologic states have been facilitated by the study of genetically determined immunologic dysfunctions in experimental animals. This article focuses on the scid mutation of the mouse (SCID mouse) that causes severe defects in the development of the immune system. The mutation appears to impair the recombination of antigen receptor genes, causing in the SCID mice a lack of functional T and B lymphocytes.

Radiosurgery of cerebral arteriovenous malformations with the dynamic stereotactic irradiation.

From December 1986 through December 1988, 33 patients with inoperable arteriovenous malformation (AVM) were treated in our center with the dynamic stereotactic radiosurgery, which uses a standard 10 MV isocentric linear accelerator. There were 18 females and 15 males with a median age of 26 years (range: 9-69) and a median follow-up time of 16 months (range: 7-32). The arteriovenous malformation volumes treated ranged from 0.

[Myasthenia gravis].

The present review updates myasthenia gravis. Immunopathogenesis of this condition, the clinical picture and degrees of involvement according to Osserman's classification, diagnostic procedures currently available, medical treatment and repercussion on the patient who is going yo be thymectomized are discussed. We review the works of several authors as far as concern to the use of muscle relaxants in myasthenic patients, peroperative monitoring of neuromuscular blockade, anesthetic techniques to be used, analgesia and intensive care required during postoperative period.

Dynamic stereotactic radiosurgery in arteriovenous malformation. Preliminary treatment results.

From December 1986 through August 1988, 25 patients with intracranial arteriovenous malformations underwent radiosurgery with the dynamic stereotactic irradiation technique. The prescribed dose at isocenter ranged from 50 Gy to 55 Gy, given as a single fraction in 92% of the patients. Field sizes, defined at the 90% isodose surface, varied from 5 mm to 25 mm and were chosen in order to deliver 20 to 25 Gy at the periphery of the malformation.

Radiosurgery with photon beams: physical aspects and adequacy of linear accelerators.

The question of the adequacy of isocentric linear accelerators (linacs) for use in radiosurgery is addressed. The general physical requirements for radiosurgery, mainly a high spatial and numerical accuracy of dose delivery, reasonable treatment time, and low skin and leakage dose as well as cost considerations are examined. Various linac-based procedures are analyzed in view of their ability to meet these requirements and are contrasted with the clinically proven system of the Gamma unit.

HLA- and H-2-associated variations of intra- and extracellular magnesium content.

Erythrocyte and plasma magnesium (EMg, PMg) levels have been shown to be genetically controlled in human and mouse. The possible association of these genetic factors with the major histocompatibility complex (MHC) (HLA and H-2) was investigated. Among unrelated adult male blood donors, HLA-B35 carriers have PMg (P less than 0.

Influence of different regions of the H-2 complex on the rate of clearance of Salmonella typhimurium.

The rate of clearance of Salmonella typhimurium from the mouse spleen is under H-2 linked genetic control. The results of the present study, with H-2 recombinant mice on a C57BL/10 background, suggest the involvement of at least two loci, one in the D region and the other in the K-A alpha chromosomal segment.

Evaluation of lung dose correction methods for photon irradiations of thorax phantoms.

Radiation absorbed dose in lung is measured and calculated using several algorithms available on commercial treatment planning systems. Phantoms resembling the human thorax are used and irradiated with small and large photon beams of 60Co, 4, 6, and 10 MV X ray energies. The applicability and usefulness of the different calculation methods in clinical situations is discussed.

Differential regulation of ABA-induced 23-25 kDa proteins in embryo and vegetative tissues of the viviparous mutants of maize.

Previous studies have identified a set of highly phosphorylated proteins of 23-25 kDa accumulated during normal embryogenesis of Zea mays L. and which disappear in early germination. They can be induced precociously in embryos by abscisic acid (ABA) treatment.

Electron dose rate and photon contamination in electron arc therapy.

The electron dose rate at the depth of dose maximum dmax and the photon contamination are discussed as a function of several parameters of the rotational electron beam. A pseudoarc technique with an angular increment of 10 degrees and a constant number of monitor units per each stationary electron field was used in our experiments. The electron dose rate is defined as the electron dose at a given point in phantom divided by the number of monitor units given for any one stationary electron beam.

Alternative T cell receptor gene usage induced by self tolerance.

Ab-restricted, H-Y-specific T cell clones from C57BL/6 mice were found to use predominantly V beta 6 T cell receptor genes, conferring Mls-1a reactivity. However, the expression of Mls-1a as a self antigen in (DBA/2 x C57BL/6)F1 mice did not turn these mice into nonresponders to H-Y. Instead of V beta 6, they used other T cell receptor genes in this response.

Radiosurgery with high energy photon beams: a comparison among techniques.

The presently known radiosurgical techniques with high energy photon beams are based either on the commercially available Gamma unit utilizing 201 stationary cobalt beams or on isocentric linear accelerators. The techniques using linear accelerators are divided into the single plane rotation, the multiple non-coplanar arcs, and the dynamic rotation. A brief description of these techniques is given, and their physical characteristics, such as precision of dose delivery, dose fall-off outside the target volume, and isodose distributions are discussed.

Specificity of anti-H-2 class I antibodies induced by syngeneic immunization with Sendai virus-treated cells is regulated by the mouse MHC and viral antigens. No evidence for MHC-restricted virus-specific antibodies.

In a previous study, we searched for Sendai virus (SV)-specific antibodies that were restricted in their binding by self-major histocompatability complex (MHC) antigens. In C57BL/6 (B6; H-2b) mice, most of the sera obtained after i.p.