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PubMed1996

Covalent dimerization of ribulose bisphosphate carboxylase subunits by UV radiation.

The effect of UV radiation (UV-A, UV-B and UV-C) on ribulose bisphosphate carboxylase from a variety of plant species was examined. The exposition of plant leaves or the pure enzyme to UV radiation produced a UV-dependent accumulation of a +5 kDa polypeptide (P65). Different approaches were utilized to elucidate the origin and structure of P65: electrophoretic and fluorographic analyses of 35S-labelled ribulose bisphosphate carboxylase exposed to UV radiation and immunological experiments using antibodies specific for P65, for the large and small subunits of ribulose bisphosphate carboxylase and for high-molecular-mass aggregates of the enzyme. These studies revealed that P65 is a dimer, formed by the covalent, non-disulphide linkage of one small subunit with one large subunit of ribulose bisphosphate carboxylase. For short periods of time (< 1 h), the amount of P65 formed increased with the duration of the exposure to the UV radiation and with the energy of the radiation applied. Prolonged exposure to UV radiation (1-6 h) resulted in the formation of high-molecular-mass aggregates of ribulose bisphosphate carboxylase. Formation of P65 was shown to depend on the native state of the protein, was stimulated by inhibitors of enzyme activity, and was inhibited by activators of enzyme activity. A UV-independent accumulation of P65 was also achieved by the in vitro incubation of plant crude extracts. However, the UV-dependent and the UV-independent formation of P65 seemed to occur by distinct molecular mechanisms. The UV-dependent accumulation of P65 was immunologically detected in all species examined, including Lemna minor, Arum italicum, Brassica oleracea, Triticum aestivum, Zea mays, Pisum sativum and Phaseolus vulgaris, suggesting that it may constitute a universal response to UV radiation, common to all photo-synthetic tissues.

Chromatography↗
PubMed1964

HOMEOSTASIS OF ANTIBODY FORMATION IN THE ADULT RAT.

Passive immunization of rats with homologous anti-sheep erythrocyte serum markedly inhibited the primary antibody response to various doses of sheep erythrocytes. Inhibition was "specific" and apparently produced by either "19S" or "7S" antibody to the antigen. Passive immunization inhibited splenic hyperplasia associated with the primary antibody response. Passive immunization 24 hours after active immunization effectively inhibited the primary antibody response. The markedly suppressive effect of specific antibody on the primary antibody response contrasted sharply with the absence of this effect on the secondary response. Antigen-antibody complexes formed in vitro elicited no measurable primary antibody response but did elicit a high secondary response. Exposure of normal spleen cells to the antibody in vivo or in vitro suppressed their response to the antigen in x-irradiated recipients. In contrast, cells from previously immunized animals transferred to x-irradiated animals produced antibody in the presence of passively given antibody. Thus, "potential antibody-forming cells" from normal animals were unresponsive to the antigen in the presence of specific antibody, while "antibody-forming cells" from previously immunized animals responded to the antigen in the presence of antibody. Presumably, antibody actively produced in small quantities by a few antibody-forming cells might inhibit antibody formation by potential antibody-forming cells. Confirmation of this suggestion was obtained by showing that some animals initially injected with small doses of antigen failed to produce measurable antibody to subsequent injections of larger doses of the antigen. Low doses of antigen capable of inducing unresponsiveness produced no measurable circulating antibody, but these doses did produce increased numbers of plaque-forming (antibody-releasing) cells in spleens of rats. Thus, the formation of specific antibody may provide a homeostatic or "feed-back" mechanism which controls or limits production of specific antibody to the portion of the antibody-forming system previously stimulated by the antigen. This mechanism may account in part for immunological unresponsiveness produced in certain other related experimental systems.

Animals↗
PubMedDate not supplied

[The immune system indices of hypertension patients exposed to ionizing radiation].

We studied immunologic status in patients with stage II hypertensive disease (HD): there were 92 Kievans and 46 subjects living in the area with excessive radiation within a 30-km radius of the Chernobyl Nuclear Power Plant; control group comprised 20 apparently healthy men (donors of the city station of blood transfusion). In HD patients the T-lymphocyte count was found to be reduced as was the content of T-suppressors and T-helpers, the activity of the B-immune system tending to be on the increase. Suppression of the T-lymphocyte suppressive function and elevation of the immunoglobulin G content result in an accelerated formation of circulating immune complexes, this indicating evolution of disturbances in immune complexes and an influence being exerted on the development of vascular affections and progression of atherosclerosis being promoted in these patients. Changes in the immune system tended to be more pronounced in st. II HB patients residing in the area with abnormal radiation than they were in the same category of patients--inhabitants of Kiev--this being supposedly a reason for disease progression in them.

Adult↗
PubMed2006

Carnosine may reduce lung injury caused by radiation therapy.

Ionising radiation is known one of the most effective tools in the therapy of cancer but in many thoracic cancers, the total prescribed dose of radiation that can be safely administered to the target volume is limited by the risk of complications arising in the normal lung tissue. One of the major reasons for cellular injury after radiation is the formation of reactive oxygen species (ROS). Radiation pneumonitis is an acute phase side-effect which generally subsides after a few weeks and is followed by a chronic phase characterized by inflammation and fibrosis, that can develop months or years after irradiation. Carnosine is a dipeptide composed by the amino acids beta-histidine and l-alanine. The exact biological role of carnosine is not totally understood, but several studies have demonstrated that it possesses strong and specific antioxidant properties, protects against radiation damage,and promotes wound healing. The antioxidant mechanism of carnosine is attributed to its chelating effect against metal ions, superoxide dismutase (SOD)-like activity, ROS and free radicals scavenging ability . Either its antioxidant or anti-inflammatuar properties, we propose that carnosine ameliorates irradiation-induced lung injury. Thus, supplementing cancer patients to whom applied radiation therapy with carnosine, may provide an alleviation of the symptoms due to radiation-induced lung injury. This issue warrants further studies.

Carnosine↗
PubMed1986

Bestatin treatment enhances the recovery of radiation induced impairments of the immunological reactivity of the blood lymphocyte population in bladder cancer patients.

Bestatin, an immunostimulating substance of microbial origin, was examined for its capacity to augment immune responses of blood lymphocytes in bladder cancer patients having received a full course of local irradiation (64 Gy). Following irradiation the patients became lymphopenic and the lymphocytes exhibited impaired mitogenic responses to phytohemagglutinin (PHA) and purified protein derivative of tuberculin (PPD) and reduced poke weed mitogen induced secretion of immunoglobulins in vitro. Patients who were randomized to receive daily oral Bestatin treatment exhibited enhanced recoveries of PHA- and PPD-responses and enhanced recovery of the IgM secreting capacity compared to irradiated patients who did not receive Bestatin. Repopulation of the blood lymphocyte population, however, was not enhanced by Bestatin treatment. It is concluded that Bestatin treatment may enhance the recovery of radiation induced functional defects of the immune system in cancer patients.

Adjuvants, Immunologic↗
PubMed1992

The effect of AS101 on the reconstitution of T-cell reactivity following irradiation or cyclophosphamide treatment.

AS101 (ammonium trichloro[dioxyethylene-O-O']tellurate) is a new synthetic compound previously described by us as having immunomodulating properties and minimal toxicity. Phase II clinical trials are currently in progress with AS101 on cancer patients. AS101 has been recently found to have both radioprotective and chemoprotective effects on hemopoiesis of irradiated mice or mice treated with cyclophosphamide (CYP). In this study the effect of AS101 on the recovery of the immune system from sublethal irradiation or CYP treatment was assessed. Mice were injected once with AS101 24 h before being irradiated with 450 cGy or treated with 250 mg/kg body weight CYP. At various time points after treatment the functional capacity of the immune system was determined. It was found that AS101 could significantly reduce the decrease in the number of spleen cells and thymocytes, the decrease in the proliferation rate of these cells to the T-cell mitogen concanavalin A, and the decrease of interleukin 2 secretion by spleen cells. AS101 could initially protect these functions because they were increased over control levels immediately 24 h after treatment. AS101 was also shown to normalize the distribution of T-cell subsets that was impaired following both treatments. These results suggest an immunoregulatory role for AS101 in counteracting chemotherapy and radiation-induced immunological suppression as well as its usefulness as an adjunct treatment of cancer when used in combination with CYP or irradiation.

Animals↗
PubMed1999

Decreased proportion of CD4 T cells in the blood of atomic bomb survivors with myocardial infarction.

Epidemiological studies of the atomic bomb survivors have suggested dose-related increases in mortality from diseases other than cancer. Cardiovascular disease is one such noncancer disease for which increases in both mortality and incidence have been found to be associated with radiation dose. Immunological studies have revealed long-term impairment of T-cell-mediated immunity, especially involving deficiencies of CD4 helper T cells, in atomic bomb survivors. In the present study, we investigated whether decreases in CD4 T cells were associated with myocardial infarction in atomic bomb survivors. Of 1,006 survivors examined to determine the proportion of CD4 T cells in peripheral blood lymphocytes, 18 persons had a history of myocardial infarction. The proportion of CD4 T cells was significantly decreased with increased radiation dose [corrected]. Further, the prevalence of myocardial infarction was significantly greater in individuals with a lower proportion of CD4 T cells. These results suggest that myocardial infarction in atomic bomb survivors may be associated with defects in CD4 helper T cells.

Aged↗
PubMed2003

Hemopoietic function after use of IL-1 with chemotherapy or irradiation.

IL-1 has putative chemo- and radioprotective properties, but its effects on primitive hemopoietic stem cell (PHSC) and early multilineage precursor function when given with these modalities is unknown. C57BL6/J (B6) mice, given IL-1 20 h before cyclophosphamide (200 mg/kg for four biweekly doses) or before irradiation (500 cGy), were sacrificed after 4 wk. Their marrow was used as donor cells, and that from B6-Hbb(dGpi1a) (B6-GPI) mice was used as competitor cells in competitive repopulation. Percentages of B6 cells were measured at 30 and 150 days. Stem cell numbers were estimated using binomial statistics. IL-1 alone did not affect stem cell function. As expected, significant declines in early multilineage precursor and PHSC function occurred with chemotherapy and radiation alone. IL-1 with chemotherapy led to exacerbation of these losses in function and numbers (p < 0.05). A similar reduction in function occurred using IL-1 before irradiation. In summary, IL-1 with chemotherapy or radiation worsened chemotherapy- and radiation-induced functional damage to PHSC and other hemopoietic precursors, suggesting that improvements in survival do not necessarily translate into preservation of hemopoietic function.

Animals↗
PubMed1975

Daily periodicity in the activity of a slide used to perform immunologic reactions at a liquid-solid interface.

Nickel-plated slides were prepared by evaporating a nickel layer (congruent to 4000 A thick) on glass slides in the presence of a magnetic field whose lines of force were perpendicular to the surface of the slides. Such slides are called active. After being coated with a layer of bovine albumin, they could absorb a layer of antibodies 70-80 A thick. However, if the active slides before they were coated with bovine serum albumin, were submitted to a magnetic field with lines of force parallel to the surface, the layer of antibodies absorbed was only 40 A thick. They had become inactive. It has been found that slides remain active at night but that shortly after sunrise they become slowly inactivated and reach a minimum in their activity at exactly the midday period. They regain full activity at sunset. It is shown that the inactivation results from a solar radiation that can be stopped by 3.5 cm of lead. On December 13th, 1974 there was an eclipse of the sun with 65% occultation at noon (Daylight Saving Time). The activity of the slide at noon was 65% of the maximum activity (83 A) observed before sunrise. The thickness of the adsorbed layer of antibodies were 75 A instead of 63 A observed in the absence of the eclipse. The activation of the slides originates in a radiation of non-solar origin that is adsorbed by 1 can of lead.

Animals↗
PubMed2001

Primary biliary cirrhosis among atomic bomb survivors in Nagasaki, Japan.

Despite rapid progress in methods for analyzing radiation effects, much remains to be learned about the mechanisms and processes of radiation-induced immunological dysfunction. Among 17,899 sera obtained from atomic bomb survivors in Nagasaki, Japan, sera from 484 participants who complied with a reexamination for alkaline phosphatase (ALP) were tested for antimitochondrial antibody (AMA) by indirect immunofluorescence, and autoantibodies against 2-oxo-acid dehydrogenase complex (2-OADC) by immunoblotting to investigate the prevalence of primary biliary cirrhosis (PBC). Of these 484 sera, 28 (5.8%) were seropositive for AMA. The 484 participants were divided into three groups according to distance from the hypocenter: 72 who were exposed within 1999 m (closest group), 368 from 2000 to 5999 m (intermediate distant group), and 44 outside 6000 m (distant group). The positivity rates for AMA in these three groups were 6/72 (8.3%), 22/368 (6.0%), and 0/44 (0%), respectively (P =.08). Furthermore, high titers ( > 1:320) of AMA were observed in 3/6 (50%) AMA-positive sera from the closest group, in contrast to 4/22 (18%) from the intermediate distant group, although there was no significant correlation between AMA titer and distance from the hypocenter (P =.07). Of these 28 AMA-positive sera, 11 (39%) were from participants who had already been diagnosed with PBC, and 25 (89%) contained antibodies against at least one component of 2-OADC enzymes by immunoblotting. Therefore, the prevalence of PBC was estimated to be at least 615 cases per million (792 per million women). Our results suggest that the prevalence of PBC in atomic bomb survivors in Nagasaki is higher than that reported for the general population in Japan, and a further survey of the environmental factors, including radiation exposure, that predispose to PBC would be needed for understanding this disease of unknown etiology.

Aged↗
PubMed1997

Phosphorylation of light-harvesting complex II and photosystem II core proteins shows different irradiance-dependent regulation in vivo. Application of phosphothreonine antibodies to analysis of thylakoid phosphoproteins.

An immunological approach using a polyclonal phosphothreonine antibody is introduced for the analysis of thylakoid protein phosphorylation in vivo. Virtually the same photosystem II (PSII) core phosphoproteins (D1, D2, CP43, and the psbH gene product) and the light-harvesting chlorophyll a/b complex II (LHCII) phosphopolypeptides (LHCB1 and LHCB2), as earlier identified by radiolabeling experiments, were recognized in both pumpkin and spinach leaves. Notably, the PSII core proteins and LHCII polypeptides were found to have a different phosphorylation pattern in vivo with respect to increasing irradiance. Phosphorylation of the PSII core proteins in leaf discs attained the saturation level at the growth light intensity, and this level was also maintained at high irradiances. Maximal phosphorylation of LHCII polypeptides only occurred at low light intensities, far below the growth irradiance, and then drastically decreased at higher irradiances. These observations are at variance with traditional studies in vitro, where LHCII shows a light-dependent increase in phosphorylation, which is maintained even at high irradiances. Only a slow restoration of the phosphorylation capacity for LHCII polypeptides at the low light conditions occurred in vivo after the high light-induced inactivation. Furthermore, if thylakoid membranes were isolated from the high light-inactivated leaves, no restoration of LHCII phosphorylation took place in vitro. However, both the high light-induced inactivation and low light-induced restoration of LHCII phosphorylation seen in vivo could be mimicked in isolated thylakoid membranes by incubating with reduced and oxidized dithiothreitol, respectively. We propose that stromal components are involved in the regulation of LHCII phosphorylation in vivo, and inhibition of LHCII phosphorylation under increasing irradiance results from reduction of the thiol groups in the LHCII kinase.

Chloroplasts↗
PubMed1995

Inhibition of natural killer cell-mediated bone marrow graft rejection by allogeneic major histocompatibility complex class I, but not class II molecules.

The role of major histocompatibility complex (MHC) class I and class II molecules in natural killer (NK) cell-mediated rejection of allogeneic, semisyngeneic and MHC-matched bone marrow grafts was investigated. The use of beta 2-microglobulin (beta 2m) -/- and beta 2m +/- mice as bone marrow donors to MHC-mismatched recipients allowed an analysis of whether the presence of semi-syngeneic and allogeneic MHC class I gene products would be triggering, protective or neutral, in relation to NK cell-mediated rejection. Loss of beta 2m did not allow H-2b bone marrow cells to escape from NK cell-mediated rejection in allogeneic (BALB/c) or semi-allogeneic (H-2Dd transgenic C57BL/6) mice. On the contrary, it led to stronger rejection, as reflected by the inability of a larger bone marrow cell inoculum to overcome rejection by the H-2-mismatched recipients. In H-2-matched recipients, loss of beta 2m in the graft led to a switch from engraftment to rejection. At the recipient level, loss of beta 2m led to loss of the capability to reject H-2-matched beta 2m-deficient as well as allogeneic grafts. When MHC class II-deficient mice were used as donors, the response was the same as that against donors of normal MHC phenotype: allogeneic and semi-syngeneic grafts were rejected by NK cells, while syngeneic grafts were accepted. These data suggest a model in which allogeneic class I molecules on the target cell offer partial protection, while certain syngeneic class I molecules give full protection from NK cell-mediated rejection of bone marrow cells. There was no evidence for a role of MHC class II molecules in this system.

Animals↗
PubMed1987

Iatrogenic and idiopathic acute myelogenous leukemia: a comparison of clinical features and treatment complications.

We have compared the clinical and laboratory features as well as treatment complications observed in 6 patients with iatrogenic acute myelogenous leukemia (I-AML) with those of 26 patients with idiopathic acute myelogenous leukemia (AML). I-AML patients were significantly younger and their disease appeared less virulent on admission than in the AML patients. Following identical chemotherapy, hemorrhagic complications and the need for platelet support were found to be similar for both groups. Major infections, including systemic candidiasis and Gram-negative septicemias, occurred 3 times more frequently among I-AML than AML patients. More marked suppression and delayed regeneration of the bone marrow also occurred in I-AML patients. These observations and other factors, such as post-splenectomy state and inherent immune deficiency among surgically staged lymphoma patients as well as radiation induced immunologic impairment, may have contributed to the increased propensity to develop infection observed in this group of patients. Five of the 6 I-AML and 17 of the 26 AML patients achieved remission. We attribute the satisfactory outcome in our I-AML patients to treatment in a protective environment and availability of facilities for hematologic supportive care.

Adult↗