Modulation of Radioprotective Effects of Respiratory Hypoxia by Changing the Duration of Hypoxia before Irradiation and by Combining Hypoxia and Administration of Hemopoiesis-Stimulating Agents

Aim: Analysis of radioprotective effect of respiratory hypoxia on hemopoietic tissue and enhancement of this effect by heopoietic activation. Material and Methods: In mice breathing hypoxic gas mixture during total body gamma irradiation the recovery of pluripotent and committed granulocyte-macrophage progenitor cells and animal lethality were determined. Results: In mice forced to breathe 10% O₂ and 8% O₂ during irradiation, the oxygen tension in the spleen decreased to 40% and 20%, respectively, of control values. Hypoxia mitigated the lethal effect of gamma-rays and improved the recovery of hemopoiesis in compartments of pluripotent and committed progenitor cells. Enhancement of the proliferative activity in hemopoietic tissue by a cytokine (rmGM-CSF) or an immunomodulator (dextran sulfate) increased the effect of hypoxic radioprotection, while elimination of proliferative cells by hydroxyurea decreased the radioprotective effect. Adaptation of experimental animals to hypoxic conditions was found to reduce the radioprotective effect without influencing tissue partial oxygen pressure lowered by hypoxic conditions. Conclusion: The data presented confirm the radioprotective effect of 10% and 8% O₂ respiratory hypoxia on hemopoiesis. These findngs may represent a way out for further experimental and clinical research aimed at considering differential protection of various tissues by hypoxia. Ziel: Analyse von radioprotektiver Wirkung der respiratorischen Hypoxie auf das hämatopoetische Gewebe und Verstärkung dieses Effekts durch Aktivierung der Hämatopoese. Material und Methode: Es wurden bei Mäusen, die 10%igen und 8%igen Sauerstoff während der Bestrahlung geatmet haben, die Erholung von pluripotenten und unipotenten Progenitorzellen und das Überleben nach einer letalen Strahlendosis untersucht. Ergebnisse: Bei Mäusen, die 10% und 8% Sauerstoff während der Strahlentherapie geatmet haben, sank der Sauerstoffpartialdruck in der Milz auf 40% bzw. 20% in Bezug zu den Kontrollwerten ab. Die Hypoxie schwächte den letalen Effekt von Gammastrahlen ab und verbesserte die Erholung von Strahlenschädigungen in der Hämatopoese in den Kompartimenten von pluripotenten und unipotenten Progenitorzellen. Die Verstärkung der Proliferationsaktivität im hämatopoetischen Gewebe durch ein Zytokin (rmGM-CSF) oder durch einen Immunomodulator (Dextransulfat) verstärkte die hypoxische Radioprotektion, während die Elimination von proliferativen Zellen durch Hydroxyurea der radioprotektiven Effekt verringerte. Es wurde gefunden, dass die Adaption von experimentellen Tieren an die hypoxischen Bedingungen den radioprotektiven Effekt verringerte, ohne dass der durch die hypoxischen Bedingungen veränderte Sauerstoffpartialdruck im Gewebe weiter abgesenkt wurde. Schlussfolgerung: Die vorgestellten Daten bestätigen die radioprotektive Wirkung der respiratorischen Hypoxie (8% und 10% O₂) auf die Hämatopoese. Diese Entdeckungen können einen Weg für die weitere experimentelle und klinische Erforschung der unterschiedlichen Radioprotektion von verschiedenen Geweben durch respiratorische Hypoxie darstellen.     

Modulation of Radioprotective Effects of Respiratory Hypoxia by Changing the Duration of Hypoxia before Irradiation and by Combining Hypoxia and Administration of Hemopoiesis-Stimulating Agents

AIM: Analysis of radioprotective effect of respiratory hypoxia on hemopoietic tissue and enhancement of this effect by hemopoietic activation. MATERIAL AND METHODS: In mice breathing hypoxic gas mixture during total body gamma irradiation the recovery of pluripotent and committed granulocyte-macrophage progenitor cells and animal lethality were determined. RESULTS: In mice forced to breathe 10% O2 and 8% O2 during irradiation, the oxygen tension in the spleen decreased to 40% and 20%, respectively, of control values. Hypoxia mitigated the lethal effect of gamma-rays and improved the recovery of hemopoiesis in compartments of pluripotent and committed progenitor cells. Enhancement of the proliferative activity in hemopoietic tissue by a cytokine (rmGM-CSF) or an immunomodulator (dextran sulfate) increased the effect of hypoxic radioprotection, while elimination of proliferative cells by hydroxyurea decreased the radioprotective effect. Adaptation of experimental animals to hypoxic conditions was found to reduce the radioprotective effect without influencing tissue partial oxygen pressure lowered by hypoxic conditions. CONCLUSION: The data presented confirm the radioprotective effect of 10% and 8% O2 respiratory hypoxia on hemopoiesis. These findings may represent a way out for further experimental and clinical research aimed at considering differential protection of various tissues by hypoxia.     

The SNARE Vti1a-beta is localized to small synaptic vesicles and participates in a novel SNARE complex.

Specific soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor (SNARE) proteins are required for different membrane transport steps. The SNARE Vti1a has been colocalized with Golgi markers and Vti1b with Golgi and the trans-Golgi network or endosomal markers in fibroblast cell lines. Here we study the distribution of Vti1a and Vti1b in brain. Vti1b was found in synaptic vesicles but was not enriched in this organelle. A brain-specific splice variant of Vti1a was identified that had an insertion of seven amino acid residues next to the putative SNARE-interacting helix. This Vti1a-beta was enriched in small synaptic vesicles and clathrin-coated vesicles isolated from nerve terminals. Vti1a-beta also copurified with the synaptic vesicle R-SNARE synaptobrevin during immunoisolation of synaptic vesicles and endosomes. Therefore, both synaptobrevin and Vti1a-beta are integral parts of synaptic vesicles throughout their life cycle. Vti1a-beta was part of a SNARE complex in nerve terminals, which bound N-ethylmaleimide-sensitive factor and alpha-SNAP. This SNARE complex was different from the exocytic SNARE complex because Vti1a-beta was not coimmunoprecipitated with syntaxin 1 or SNAP-25. These data suggest that Vti1a-beta does not function in exocytosis but in a separate SNARE complex in a membrane fusion step during recycling or biogenesis of synaptic vesicles.     

Epithelioid Sarcoma: Need for a Multimodal Approach to Maximize the Chances of Curative Conservative Treatment

Objective

This study was designed to evaluate the impact of multimodal management on a series of epithelioid sarcoma (ES) patients treated with curative intent.

Methods

Data were collected on 69 consecutive patients treated from 1982 to 2012. Univariate and multivariate analyses were performed for tumor control and overall survival (OS).

Results

In total, 54 (78 %) patients had localized ES (M0 group). In the M0 group, 85 % of patients received multimodal management (surgery n = 50, radiotherapy n = 37, chemotherapy n = 30). Among 42 patients with limb ES, 9 (21 %) underwent amputation, and isolated limb perfusion (ILP) was required in 17 (40.5 %) to allow conservative management. Among the 45 patients who underwent conservative surgery, flap reconstructions were required in 13 (28.8 %). The median follow-up was 5.7 years. The 5-year actuarial OS rates were 54, 62, and 24 % in the entire group and the M0 and M1 groups, respectively. In the M0 group, the 5-year actuarial distant control, local control (LC), and locoregional control rates were 67, 75, and 66 %, respectively. Prognostic factors for poor OS in the multivariate analysis were tumors that were deep to the fascia (p = 0.04) and grade 3 (p = 0.005). In the univariate analysis, age <30 years (p = 0.04), the T2 stage (p = 0.04), and mass presentation (p = 0.03) correlated with decreased LC, whereas patients who underwent ILP had a significantly higher LC rate (hazard ratio 3; 95 % confidence interval 0.9–9.4; p = 0.05).

Conclusions

Multimodal management including ILP and flap reconstruction is necessary to achieve optimal conservative LC. High rates of metastasis and lymphatic spread require innovative systemic treatments.     

Subsequent application of bonding agents to a one-step self-etch adhesive — Its effect with/without previous light-curing

ObjectiveThe influence of light-curing of a one-step self-etch adhesive (1-SEA) prior to the application of different bonding agents (BA) on the micro-tensile bond strength (μTBS) to dentin after 24 h and thermal cycling was investigated. Additionally, the degree of conversion was evaluated using Fourier-transform infrared spectroscopy.MethodsThree ion-releasing BAs, BZF-21 (experimental BA), Clearfil SE Protect (CSP), and FL-Bond II (FL-II), were applied subsequently to G-Premio Bond (1-SEA, GPB). Prior to their application, GPB was either light-cured (10 s, 1000 mW/cm²) or remained uncured. GPB was used as a control and Clearfil SE Bond 2 (CSE2) as a gold-standard 2-step reference. After resin-composite build-up and 24-h water storage (24 h), half of the specimens were subjected to 15,000 thermal cycles (TC). Then, the specimens were sectioned into beams and tested under tensile load (1 mm/min). The acquired data were analyzed using a 2-way ANOVA and Student’s t-test with Bonferroni correction, and a two-parameter Weibull analysis, α = 0.05.ResultsThe μTBS of GPB increased significantly in the uncured groups with BZF-21 (24 h: p < 0.001, TC: p < 0.001) and CSP (24 h: p = 0.039, TC: p < 0.001), and in the light-cured group with CSP after TC (p = 0.044). The groups with FL-II were not significantly different from GPB (p = 1). No significant difference was found between CSE2 and the uncured groups GPB + BZF-21 (24 h: p = 1, TC: p = 0.452) and GPB + CSP (24 h: p = 0.671, TC: p = 0.566).SignificanceBZF-21 and CSP improved the μTBS of GPB to dentin both immediately and after TC. Higher μTBSs were obtained when GPB remained uncured prior to BA application.     

Pronounced in vitro and in vivo antiretroviral activity of 5-substituted 2,4-diamino-6-[2-(phosphonomethoxy)ethoxy] pyrimidines

OBJECTIVES: To discover new potent and selective anti-human immunodeficiency virus (HIV) acyclic nucleoside phosphonate (ANP) drugs with in vivo antiretroviral activity. METHODS: New acyclic pyrimidine nucleoside phosphonate derivatives that mimic the structure of the anti-HIV purine nucleoside phosphonates 9-(2-phosphonylmethoxyethyl)adenine (PMEA, adefovir) and (R)-9-(2-phosphonylmethoxypropyl)adenine (PMPA, tenofovir) were designed by linking the acyclic side chain of the ANPs through an ether bond to the C-6 position instead of the N-1 position of the pyrimidine ring. The compounds were evaluated against HIV and Moloney murine sarcoma virus (MSV) in cell culture, including a broad variety of HIV-1 clade clinical isolates and relevant mutant (drug-resistant) HIV-1 isolates. Their antiviral activities were correlated and investigated in an in vivo model consisting of MSV-infected newborn mice. MSV-induced tumour formation and associated death were recorded in drug-treated animals. RESULTS: Several 5-substituted 6-[2-(phosphonomethoxy)ethoxy]-2,4-diaminopyrimidine (PMEO-DAPy) analogues were found to inhibit a broad variety of HIV-1 clinical isolates. They showed a more favourable cross-resistance profile to mutant virus isolates than adefovir and tenofovir. There was a close correlation between inhibition of MSV in C3H/3T3 cells and inhibition of HIV-1 in CEM cells. The PMEO-DAPy derivatives potently inhibited MSV-induced tumour cell formation in newborn mice. The 5-methyl analogue PMEO-5-Me-DAPy proved markedly more inhibitory to MSV-induced tumour cell formation and associated animal death than its unsubstituted parent PMEO-DAPy derivative. When compared with adefovir, PMEO-5-Me-DAPy was less toxic and more antivirally active in MSV-infected mice. CONCLUSIONS: PMEO-5-Me-DAPy deserves further (pre)clinical investigations as a candidate anti-HIV drug.