Long-term biological effects induced by ionizing radiation--implications for dose mediated risk.

Ionizing radiations are considered to be risk agents that are responsible for the effects on interaction with living matter. The occurring biological effects are due to various factors such as: dose, type of radiation, exposure time, type of biological tissue, health condition and the age of the person exposed. The mechanisms involved in the direct modifications of nuclear DNA and mitochondrial DNA are reviewed. Classical target theory of energy deposition in the nucleus that causes DNA damages, in particular DNA double-strand breaks and that explanation of the biological consequences of ionizing radiation exposure is a paradigm in radiobiology. Recent experimental evidences have demonstrated the existence of a molecular mechanism that explains the non-targeted effects of ionizing radiation exposure. Among these novel data, genomic instability and a variety of bystander effects are discussed here. Those bystander effects of ionizing radiation are fulfilled by cellular communication systems that give rise to non-targeted effects in the neighboring non irradiated cells. This paper provides also a commentary on the synergistic effects induced by the co-exposures to ionizing radiation and various physical agents such as electromagnetic fields and the co-exposures to ionizing radiation and chemical environmental contaminants such as metals. The biological effects of multiple stressors on genomic instability and bystander effects are also discussed. Moreover, a brief presentation of the methods used to characterize cyto- and genotoxic damages is offered.

In vitro screening of Crataegus succulenta extracts for free radical scavenging and 15-lipoxygenase inhibitory activities.

UNLABELLED: Crataegus succulenta Schrad. ex Link is widely spread in North America. A literature survey revealed no studies on the chemical composition and biological effects of this species. AIM: The aim of the present study was to investigate the phenolic content, free radical scavenging and 15-lipoxygenase inhibitory effects of Crataegus succulenta leaf and flower extracts. MATERIAL AND METHODS: Total phenolic, flavonoid and proanthocyanidin contents were quantified by spectrophotometric methods. Both extracts were evaluated for their ability to scavenge DPPH, superoxide anion and hydroxyl radicals and to inhibit 15-lipoxygenase activity. RESULTS: There were noticed no striking differences in the total phenolic, flavonoid and proanthocyanidin contents between leaf and flower extracts. Both extracts showed similar 15-lipoxygenase inhibitory effects. Flower extract scavenged more effectively DPPH and superoxide radicals while leave extract was more active against hydroxyl radical. In superoxide anion radical scavenging assay, both extracts were more active than (+)-catechin. In hydroxyl radical scavenging and 15-lipoxygenase inhibition assays, the extracts were only 4-5 times less active than (+)-catechin. CONCLUSIONS: The high antioxidant potential of Crataegus succulenta extracts suggest a possible use as ingredients in functional foods for the prevention of oxidative stress-related diseases.

Polyphenol-rich extract from Pinus sylvestris L. bark--chemical and antitumor studies.

UNLABELLED: Pinus sylvestris L. is a very important timber tree in Romania, the bark being the main waste from the wood processing. AIM: The aim of this study was to investigate the chemical composition and antitumor effects against HeLa cells of a polyphenol-rich extract from Pinus sylvestris L. bark. MATERIAL AND METHODS: The polyphenolic content and profile were analyzed by means of spectrophotometry and RP-HPLC-UV/ESI-MS in the negative ion mode. The antitumor activity was investigated using two in vitro assays: MTT and flow cytometric apoptosis assays. RESULTS: Pine bark extract contained a high total phenolic content (48.16 +/- 0.29%). RP-HPLC-UV/ESI-MS analysis allowed the identification of taxifolin, a taxifolin-hexoside and several procyanidins (two monomers, three dimers and three trimers). At 200 microg/mL, pine bark extract exhibited a high cytotoxicity against HeLa cells (82.10 +/- 1.95%). Flow cytometry revealed the ability of pine bark extract to induce apoptosis: 71.97 +/- 0.96% apoptotic cells were determined in HeLa cells after a 48 h incubation with pine bark extract (200 microg/mL). CONCLUSIONS: The ability of pine bark extract to reduce viability and induce apoptosis in HeLa cells suggests the presence of compounds with antitumor properties and encourages further studies for their isolation and characterization.

Is it enough scintigraphy for everyone? A cross-sectional analysis regarding the impact of justice in the distribution of health care resources.

AIMS: The aim of this study was to evaluate the influence of three demographic criteria: gender, age and education level on the patients that perform a scintigraphy. MATERIALS AND METHODS: The cross-sectional study was applied to 220 patients to whom it was prescribed a scintigraphy by their treating physician. Of these, 74 were men and 145 women, 10 children and 210 adults. According to their education, 88 people did not graduate a high school, a total of 56 people graduated a high school, 27 persons graduated a college, 22 people had a university diploma and 26 people a PhD title. The chi-square test was used to analyze the frequencies for the measurable variables on a nominal scale. The significance threshold is considered to be 0.05, so, only the values which are smaller were taken into consideration. We presented and analyzed only the data that fulfill this condition. RESULTS AND DISCUSSION: From our study it has been found that gender criterion played an important role in performing a scintigraphy for the first time. 71.6% of male patients were undergoing a scintigraphy for the first time. The frequency of exploration by scintigraphy is increasing if you are a female patient than if you are a male patient: chi-square calculated value is chi2 (3)=12.398, p=0.006. From our study it has been found that age item plays an important role in the scintigraphy investigations for all the patients. The first scintigraphy was significantly performed in the 40-50 years old gap, whilst for the patients being aged over 60; they were probably not performing a first time scintigraphy. We did not find significant statistical differences in respect of the education level. CONCLUSIONS: So, we can conclude that access to that medical investigation is not depending on the socioeconomic status of the patient, but in some occasions, the number and the frequency distribution of performing a scintigraphy depend on gender and age. We can also conclude that the principle of egalitarianism is fulfilled and so the justice principle in the distribution of health care resources must be reevaluated.

Bioactivity screening of Pinus brutia bark extracts: superoxide dismutase-like and nitric oxide scavenging effects.

UNLABELLED: In the Eastern Mediterranean region the wood of Pinus brutia Ten. is used as building material, the bark being the main waste of the wood production processes. A study was designed to explore possible medicinal applications for the bark waste. This paper reports on the superoxide dismutase-like and NO scavenging effects of bark extracts. MATERIAL AND METHODS: Bark extracts (a raw hydromethanolic extract and its fractions) were initially screened regarding their ability to scavenge DPPH radical. The superoxide dismutase-like and NO scavenging effects were further evaluated. Catechin and quercetin were the positive controls in all antioxidant assays. RESULTS AND DISCUSSION: According to the EC50 values, all extracts (11.8 +/- 0.1 - 21.10 +/- 0.05 microg/ml) efficiently scavenged DPPH radical in comparison to quercetin (3.13 +/- 0.05 microg/ml) and catechin (6.36 +/- 0.05 microg/ml). The raw extract, diethyl ether and ethyl acetate fractions (449.46 +/- 1.75, 115.43 +/- 0.25 and 278.3 +/- 2.3 microg/ml, respectively) exhibited higher superoxide dismutase-like effects in comparison to catechin (> 645.1 microg/ml). In NO scavenging assay, the raw extract, ethyl acetate and aqueous fractions (160.63 +/- 0.85, 162.96 +/- 0.52 and 160.23 +/- 2.35 microg/ml, respectively) showed a scavenging ability similar to that of quercetin (156.76 +/- 5.05 microg/ml) and higher than the one developed by catechin (242.66 +/- 7.65 microg/ml). CONCLUSIONS: As superoxide anion and NO are important mediators in inflammation, our results support a possible use of Pinus brutia bark waste to develop nutraceuticals with efficiency in disorders involving oxidative and inflammatory stress.

Rapid response to alefacept given to patients with steroid resistant or steroid dependent acute graft-versus-host disease: a preliminary report.

We evaluated the effect of alefacept (Amevive), a novel dimeric fusion protein, in steroid resistant/dependent acute graft-versus-host-disease (aGVHD). Seven patients were treated in eight aGVHD episodes. GVHD grade at treatment initiation and at peak ranged 2-4 (median 2.5) and 2-4 (median 4), respectively. System involvement at GVHD peak included skin (n=7), gastrointestinal tract (n=5) and liver (n=3). All patients responded. However, one patient with skin GVHD and two with gastrointestinal GVHD featuring an early initial response (IR) exacerbated and CR was not achieved. Skin GVHD responded rapidly with a median of 1 day to IR and 7 days to CR. Intestinal response was slower with median 7.5 days to IR. Of the four patients that achieved IR, CR was achieved in only one (40 days to CR). None of the patients had significant hepatic GVHD before treatment so no hepatic effect of alefacept could be determined. No immediate alefacept-related side effects were observed. Late side effects included infections (aspergillus sinusitis, pneumonia, bacteremia, pharyngeal thrush), pancytopenia and hemorrhagic cystitis. Three patients had CMV reactivation while on alefacept. We conclude that alefacept may have a beneficial effect in controlling aGVHD. Further investigations in larger cohorts of patients and controlled studies are warranted.

Low transplant-related mortality with allogeneic stem cell transplantation in elderly patients.

Historically, age >60 years was considered a contraindication for allogeneic stem cell transplantation (allo-SCT). In recent years, elderly (>60 years) patients have become eligible for allo-SCT due to the application of reduced intensity conditioning (RIC). The present report summarizes our cumulative experience in a cohort of 17 elderly patients (age 60-67, median 62.5 years) with hematological malignancies treated with 18 allo-SCT procedures, mostly nonmyeloablative. In all, 14 patients received fludarabine and busulfan/busulfex regimen, three patients were conditioned with the fludarabine and low-dose TBI and one patient received busulfan alone. All patients displayed tri-lineage engraftment. The time to recovery of absolute neutrophil count >/=0.5 x 10(9)/l was 9-27 days (median 14 days). The time interval to platelet recovery >/=20 x 10(9)/l was 3-96 days (median 11 days). Veno-occlusive disease occurred only in 3/18 procedures and subsided with conventional treatment. Nonfatal transplant-related complications occurred in 6/18 (33.3%) procedures including: renal failure, arrhythmia, CNS bleeding, cystitis, typhlitis and gastrointestinal bleeding. Transplant-related mortality occurred in 6/18 (33.3%) episodes. Of the 17 patients, 12 (12/18 episodes) were discharged. Five of 17 (29%) patients survived (median follow-up 11 m, range 8-53 m). Our data suggest that RIC-allo-SCT may be safely applied in the elderly, suggesting that allogeneic immunotherapy may become an important tool for treatment of hematological malignancies without an age limit.

A new minimally ablative stem cell transplantation procedure in high-risk patients not eligible for nonmyeloablative allogeneic bone marrow transplantation.

Nonmyeloblative stem cell transplantation (NST, SCT) aims to induce host-versus-graft tolerance for subsequent immunotherapy of underlying disease with alloreactive donor lymphocytes, focusing on well-tolerated conditioning suitable for elderly individuals or for other risk factors. However, there is a subset of high-risk patients who cannot tolerate NST. A new protocol consisting of fludarabine 30 mg/m(2) x 6 days (days -8 to -2), very-low-dose busulfan (2 mg/kg x 2 days, days -6 to -5), without anti thymocyte globulin (ATG), was employed in 11 high-risk patients aged 26-58 years. Graft-versus-host-disease (GVHD) prophylaxis consisted of low-dose and short-course cyclosporine-A (CSA) alone. One patient died during the nadir due to pulmonary complications. Other patients showed rapid three-lineage engraftment, without complete aplasia; 6/10 patients did not require platelet transfusion and 8/10 had full donor chimerism without transient mixed chimerism. Owing to intentional selection of highly poor-risk patients, overall mortality was high and only one patient survived. Acute GVHD (>/=grade I) occurred in 8/10 evaluable patients, 5/8 while off CSA; 5/8 developed grade III-IV acute GVHD. It appears that our modified, minimally ablative stem cell transplantation (MST) may be used for high-risk patients in need of allo-SCT. Furthermore, although the MST conditioning is not myeloablative, it results in myeloablation of the host hematopoietic system, mediated by alloreactive lymphocytes.

3-D surface reconstruction of multiple sclerosis lesions using spherical harmonics.

A new approach to approximate the 3-D shape of multiple sclerosis (MS) lesions and to calculate their volumes is presented. The suggested method utilizes sets of MS lesion contours taken from segmented MR images and approximates their 3-D surfaces by spherical harmonics. This method was applied to obtain 3-D reconstructions of in vivo and simulated MS lesions and to calculate their volumes. The results show good geometrical approximations of the original MS lesions' 3-D shapes and good consistency in volume estimation independent of the size of the lesions. The average volume estimation error was smaller than the commonly used technique of slice stacking (15.5 +/- 13.4% and 13.1 +/- 10.1% vs. 25.0 +/- 17.0%). The method presented here offers a tool for analyzing the geometrical characteristics of MS lesions in 3-D as well as their volumes. The geometrical information may potentially serve as an additional clinical index for monitoring the disease.

Blood flow changes to the femoral head after acetabular fracture or dislocation in the acute injury and perioperative periods.

OBJECTIVES: Acute blood flow to the femoral head has been postulated to be affected negatively by traumatic acetabular fracture or dislocation. To the best of our knowledge, a prospective study that has examined acute changes in blood flow to the femoral head with respect to the timing of reduction and the effect of open reduction and internal fixation after acetabular fracture or dislocations has not been performed. DESIGN AND SETTING: From June 1994 to February 1996, fifty-four consecutive patients with hip dislocations with or without fractures of the acetabulum were entered into this investigation. The patients were categorized into three groups: isolated dislocations, fractures or dislocations requiring open reduction and internal fixation, and isolated acetabular fractures without dislocation but requiring open reduction and internal fixation. Single-photon emission computed tomography (SPECT) scans were obtained after relocations and preoperatively and postoperatively after open reduction and internal fixation of displaced acetabular fractures. RESULTS: The median dislocation time for all patients flow was 4.00 hours (range 1 to 24 hours). SPECT scanning showed a low blood flow pattern in five (9.25 percent) patients. A low blood flow pattern was seen in patients with early and late relocation times. Open reduction and internal fixation was not statistically associated with an avascular pattern of blood flow. Forty-two (78 percent) of our patients were available for follow-up, with an average of 24.3 months and a minimum of one year. There was one false-positive, one false-negative, and thirty-eight true-negative scans. CONCLUSIONS: A global loss of scintillation in the femoral head as determined by SPECT scanning occurs in some patients with hip dislocations and fractures or dislocations of the acetabulum in the early injury period. Changes in blood flow occurred in patients with short (one hour) and long (twenty-four hours) dislocation times. However, the development of avascular necrosis could not be predicted by early SPECT scanning. Until further multicenter studies are performed, SPECT scanning cannot be recommended on an acute or routine basis to predict those patients who will develop avascular necrosis. Operative approaches for open reduction of the hip and internal fixation of acetabular fractures do not appear to affect blood flow to the femoral head. Although a golden time to relocation cannot be fully established from this study, early relocation is advised to decrease the potential risk of vascular spasm, scarring, and subsequent avascular necrosis.

Loxapine intoxication: case report and literature review.

Loxapine is a dibenzoxazepine tricyclic compound used to treat schizophrenia in the United States since 1976. Metabolism includes demethylation to its primary metabolite, amoxapine. There are few documented reports of the disposition of loxapine in deaths due to overdose. This report discusses the overdose suicide of a 69-year-old white female found dead in her home by her husband. A prescription for loxapine (50-mg capsules) was found near the body. An autopsy was performed and heart blood, bile, vitreous humor, and gastric contents were submitted for toxicological analysis. The blood specimen was subjected to comprehensive testing that included volatile analysis by headspace gas chromatography (GC); acidic/neutral and basic drug screening by GC; benzodiazepine screening by high-performance liquid chromatography; opiate screening by modified immunoassay; and acetaminophen, salicylate, and ethchlorvynol screening by colorimetry. Loxapine and amoxapine were detected in the basic drug screen. No other drugs were detected in the case specimens. The respective concentrations of loxapine and amoxapine in each specimen were as follows: heart blood, 9.5 and 0.6 mg/L; bile, 28.8 and 4.7 mg/L; gastric, 278 mg/L and negative; and vitreous, 1.5 mg/L and negative. A review of the literature showed that the heart blood concentration of loxapine measured in this case was the highest reported to date. Based on the autopsy findings, patient history, and toxicology results, the cause of death was determined to be acute intoxication of loxapine and the manner, suicide.

Parenteral administration of an activating monoclonal antibody to the alpha1beta1 integrin in dogs.

In mice, monoclonal antibody (mAb) to the alpha1 integrin abrogate gastro-intestinal damage during graft-versus-host-disease (GVHD), suggesting anti alpha1 mAb as candidates for treatment in humans as well. Our current data show that one such reagent, mAb 1B3.1, when immobilized to plastic wells via rabbit- anti murine (ram) immunoglobulin (Ig) induces a protein kinase-dependent spreading of activated human T cells. Furthermore, it significantly increases the proliferative response, and expression of interleukin-2 (IL-2) receptors (R) and CD69, of resting T cells, expressing minimal integrin on the cell surface, to sub-optimal stimulation by anti-CD3 mAb. We found, in addition, that mAb 1B3.1 a) immuno-precipitates alpha1beta1 integrins from cell-surface iodinated canine epithelial cells b) is highly reactive with canine T cells after their activation and c) inhibits adhesion of canine T cells to collagen IV. Despite the potential ability of the mAb to co-activate T cells in vitro, two dogs that received 4 injections of 0.5-0.3 mg/Kg of mAb 1B3.1 remained healthy, developing only marginal transient lymphopenia. Injection of 0.75mg/Kg in a third dog induced a more marked lymphopenia, and an additional dose of 1.0 mg/Kg 2 weeks later was followed by gastrointestinal hemorrhage. importantly, the lymphopenia was associated with a greater and more persistent decrease of CD8+ than of CD4+ T cells, leading to an increase in the CD4/CD8 ratio 24 hours after the injection. Thus, despite it's co-activating effects in vitro, administration of this mAb in vivo is feasible when appropriately dosed, and may have immuno-modulatory effects.

Suppression of experimental autoimmune encephalomyelitis by intravenously administered polyclonal immunoglobulins.

Experimental autoimmune encephalomyelitis (EAE) was induced in Lewis rats either by active immunization with myelin basic protein (MBP) or by adoptive transfer using anti-MBP specific CD4(+)T cells. Treatment with human polyclonal immunoglobulins (IgG) effectively suppressed active EAE. Time-dependent experiments demonstrated that the effect of IgG was manifested only when treatment was given immediately after immunization; administration from day 7 after disease induction did not suppress the disease. In the adoptive transfer model of EAE, IgG had no effect in vivo. However, pretreatment in vitro of the antigen-specific T-cells with IgG inhibited their ability to mediate adoptive EAE, as it did in active EAE. Similarly, in vitro IgG pretreatment of the antigen-specific T-cells suppressed the proliferative response to MBP. Fluorescent Activated Cell Sorter (FACS) analysis demonstrated the binding of IgG to activated T-cell lines that was inhibited by soluble Fc molecules. The differential effects of IgG on active EAE and on the adoptive transfer of EAE suggest that IgG in vivo can suppress disease by acting during the early phase of the immune response which involves naive T cells. The inhibition of T-cell proliferation and adoptive transfer of EAE by incubation of T cells in vitro appears to require higher concentrations of IgG than those obtained in vivo.

[Intravenous immunoglobulins (IVIg) in the treatment of multiple sclerosis]. / Traitement par immunoglobulines intraveineuses (IgIV) de la sclérose en plaques.

Intravenously administered immunoglobulins (IVIg) have been used for the treatment of various autoimmune diseases. In multiple sclerosis (MS), recent studies point out the beneficial role of this treatment that reduces relapse rate and arrests disease progression in relapsing-remitting patients. In the present article, we summarize and interpret the clinical, immunological, and neuro-radiological data related to IVIg treatment in MS. A synthesis between the information gathered will enable better understanding and treatment of this chronic disease.

Immunoglobulin treatment in refractory Myasthenia gravis.

Failure to induce and maintain remission in severe exacerbations of myasthenia gravis (MG), despite optimal care, is a common problem. We evaluated the efficacy and safety of high-dose intravenous immunoglobulin (IVIg) therapy in an open-label study of 10 patients with severe generalized myasthenia and an acute deterioration unresponsive to conventional therapy including high-dose corticosteroids, cyclosporine, and azathioprine. Intravenous Ig at a loading dose of 400 mg/kg was administered daily for 5 consecutive days, with maintenance IVIg treatment at a dose of 400 mg/kg, once every 6 weeks. Significant improvement occurred in all patients, beginning at 6 +/- 2 days of treatment as measured by the Osserman scale, fatigue variables, muscle strength, and respiratory function tests. No side effects were observed during induction of remission. Further IVIg treatments were highly efficacious in maintaining the remission. The severity of the disease decreased by 2.5 +/- 0.8 grades of the Osserman scale over a period of 1 year (P <0.001), in parallel with reduction of immunosuppressive therapy as well as a decrease in acetylcholine receptor antibody titers (P < 0.01). Intravenous Ig therapy seems to be highly potent for inducing rapid improvement in refractory myasthenia during acute deterioration as well as for maintaining remission.

Dexanabinol (HU-211) effect on experimental autoimmune encephalomyelitis: implications for the treatment of acute relapses of multiple sclerosis.

Dexanabinol (HU-211) is a synthetic non-psychotropic cannabinoid which suppresses TNF-alpha production in the brain and peripheral blood. The effects of dexanabinol in rat experimental autoimmune encephalomyelitis (EAE) were studied using different doses, modes of administration and time regimes. Dexanabinol, 5 mg/kg i.v. given once after disease onset (day 10), significantly reduced maximal EAE score. Increasing the dose or treatment duration resulted in further suppression of EAE. Drug administration at earlier phases during disease induction was not effective. Histological studies supported the clinical findings demonstrating reduction in the inflammatory response in the brain and spinal cord in animals treated with dexanabinol. The results suggest that dexanabinol may provide an alternative mode of treatment for acute exacerbations of multiple sclerosis (MS).

Immunoglobulins treatment in multiple sclerosis and experimental autoimmune encephalomyelitis.

Intravenously administered immunoglobulins (IgG) treatment has several modes of action that can regulate the immune response during different steps of the inflammatory process in experimental autoimmune encephalomyelitis (EAE) and Multiple Sclerosis (MS). The immunomodulatory effects IgG are largely dependent on their ability to interact with membrane molecules of lymphocytes and monocytes. Better understanding of these mechanisms of action in relation to the pathogenesis of MS, is important in order to decide the time of initiation and the duration of treatment in MS patients. In order to have the best beneficial effect on disease course, future research should focus on the initial events that activate the disease and on the early treatment modalities of IgG in MS.

Multinuclear magnetic resonance studies of Escherichia coli adenylate kinase in free and bound forms. Resonance assignment, secondary structure and ligand binding.

The crystal structure of Escherichia coli adenylate kinase (AKe) revealed three main components: a CORE domain, composed of a five-stranded parallel beta-sheet surrounded by alpha-helices, and two peripheral domains involved in covering the ATP in the active site (LID) and binding of the AMP (NMPbind). We initiated a long-term NMR study aiming to characterize the solution structure, binding mechanism and internal dynamics of the various domains. Using single (15N) and double-labeled (13C and 15N) samples and double- and triple-resonance NMR experiments we assigned 97% of the 1H, 13C and 15N backbone resonances, and proton and 13Cbeta resonances for more than 40% of the side chains in the free protein. Analysis of a 15N-labeled enzyme in complex with the bi-substrate analogue [P1,P5-bis(5'-adenosine)-pentaphosphate] (Ap5A) resulted in the assignment of 90% of the backbone 1H and 15N resonances and 42% of the side chain resonances. Based on short-range NOEs and 1H and 13C secondary chemical shifts, we identified the elements of secondary structure and the topology of the beta-strands in the unliganded form. The alpha-helices and the beta-strands of the parallel beta-sheet in solution have the same limits (+/- 1 residue) as those observed in the crystal. The first helix (alpha1) appears to have a frayed N-terminal side. Significant differences relative to the crystal were noticed in the LID domain, which in solution exhibits four antiparallel beta-strands. The secondary structure of the nucleoside-bound form, as deduced from intramolecular NOEs and the 1Halpha chemical shifts, is similar to that of the free enzyme. The largest chemical shift differences allowed us to map the regions of protein-ligand contacts. 1H/2H exchange experiments performed on free and Ap5A-bound enzymes showed a general decrease of the structural flexibility in the complex which is accompanied by a local increased flexibility on the N-side of the parallel beta-sheet.