Unravelling performance of honeycomb structures as drug delivery systems for the isoniazid drug using DFT-D3 correction dispersion and molecular dynamic simulations

In this study, the potential of aluminum nitride (h-AlN), boron nitride (h-BN) and silicon carbide (h-SiC) nanosheets as the drug delivery systems (DDS) of isoniazid (INH) was scrutinized through density functional theory (DFT) and molecular dynamic (MD) simulations. We performed DFT periodic calculations on the geometry and electronic features of nanosheets adsorbed with INH by the DFT functional (DZP/GGA-PBE) employed in the SIESTA code. In the energetically favorable model, an oxygen atom of the C-O group of the INH molecule interacts with a Si atom of the h-SiC at 2.077 Å with an interaction energy of -1.361 eV. Charge transfer (CT) calculation by employing the Mulliken, Hirshfeld and Voronoi approaches reveals that the monolayers and drug molecules act as donors and acceptors, respectively. The density of states (DOS) calculations indicate that the HOMO-LUMO energy gap (HLG) of the h-SiC nanosheet declines significantly from 2.543 to 1.492 eV upon the adsorption of the INH molecule, which causes an electrical conductivity increase and then produces an electrical signal. The signal is linked to the existence of INH, demonstrating that h-SiC may be an appropriate sensor for INH sensing. The decrease in HLG for the interaction of INH and h-SiC is the uppermost (up to 41%) representing the uppermost sensitivity, whereas the sensitivity trend is σ(h-SiC) > σ(h-AlN) > σ(h-BN). Quantum theory of atoms in molecules (QTAIM) investigations is employed to scrutinize the nature of the INH/nanosheet interactions. The QTAIM analysis reveals that the interaction of the INH molecule and h-SiC has a partially covalent nature, while INH/h-AlN model electrostatic interaction occurs in the system and noncovalent and electrostatic interaction for the INH/h-BN model. Finally, the state-of-the-art DFT-MD simulations utilized in this study can mimic ambient conditions. The results obtained from the MD simulation show that it takes more time to bond the INH drug and h-SiC, and the INH/h-SiC system becomes stable. The results of the current research demonstrate the potential of h-SiC as a suitable sensor and drug delivery platform for INH drugs to remedy tuberculosis.

Toward functionalization of ZnO nanotubes and monolayers with 5-aminolevulinic acid drugs as possible nanocarriers for drug delivery: a DFT based molecular dynamic simulation

We have investigated the interactions between a 5-aminolevulinic acid (ALA) drug and ZnO nanostructures including ZnO monolayers and ZnO nanotubes (ZnONTs) using density functional theory (DFT) calculations. In the context of the dispersion corrected Perdew-Burke-Ernzerhof (PBE) approach, the energetics, charge transfer, electronic structure and equilibrium geometries have been estimated. As ALA is adsorbed onto/into the ZnONTs and on the ZnO monolayer with interaction energies (Eint) of -2.55/-2.75 eV and -2.51 eV, respectively, the calculated Eint values and bonding distances (∼2 Å) reveal that the interaction type is chemisorption. The ZnO nanostructures showed promising performance in the ALA drug functionalization, taking into account the interaction energy values. The band gap almost remains unchanged for both of the substrates under consideration after ALA adsorption, and the semiconductor properties of the substrates are preserved, according to the analyzed density of states (DOSs) spectra. The interaction nature of the ALA-ZnO nanostructures according to the atom in molecule (AIM) analysis was found to be polar attraction with partial covalent bonding between O and Zn. Our DFT based molecular dynamic (MD) simulation results demonstrate that, in the aqueous solution, ALA moves toward the interior sidewall of the ZnONTs and ZnO nanosheet surface and binds to the Zn atom through its O (carbonyl/hydroxyl groups) and N atoms and the hydroxyl H atom was dissociated and binds to the O atom of the ZnO surface. However, in the case of ALA adsorption onto the outer surface of ZnONTs, only the O atoms of carbonyl groups bind to the Zn atom and the structure of the drug remains undestroyed during the adsorption. The current findings shed light on the polar drug adsorption/encapsulation behavior on/into ZnO nanostructures, which may encourage further use of ZnO-based nanomaterials in the field of drug delivery and bio-functionalized nanomaterials.

Structure and magnetic properties of SiO2-FeO-CaO-Na2O bioactive glass-ceramic system for magnetic fluid hyperthermia application

Ferrimagnetic glass-ceramics comprising maghemite crystals were synthesized for magnetic fluid hyperthermia (MFH) usage. The present work is focused on the result of the chemical composition and heat treatment temperature on the magnetic behavior of ( 60 - x ) S i O 2 - ( 10 + x ) F e O - 20 C a O - 10 N a 2 O , 0 ≤ x ≤ 30 glass-ceramic system. It was observed that with the increasing of FeO from 10 to 40 wt% in the glass-ceramic compound, the percentage of maghemite phase increased. It was also seen that in the low heat treatment temperature (680 °C ), by adding iron oxide up to 30 wt%, iron cations acts as a network former, and more than this amount acts as a network modifier. In contrast, iron cations in the same composition range at high temperatures (840 °C ), acts as a network modifier. According to the VSM results, the maximum magnetization of glass-ceramics incremented from 0.23 emu/g to 0.30 emu/g with the increase in FeO percentage. It was also observed that with the increment of iron oxide percentage, the morphology of maghemite crystals changed from spherical to dumbbell-shaped.

Computational investigation on the geometry and electronic structures and absorption spectra of metal-porphyrin-oligo- phenyleneethynylenes-[60] fullerene triads

In this work, we focus our attention on the influence of 2nd-row transition metals on the structural geometries, electronic structures, and absorption characteristics of porphyrin linked with the C₆₀ fullerene with oligo-p-phenyleneethynylenes (MP-C₆₀-oligo-PPEs) compounds. The DFT/B3PW91-D3 and CAM-B3LYP-D3/6-31G (d) calculations revealed that various metals embedded within the porphyrin moiety give different bridge conformations and different HOMO-LUMO energy levels. We calculate the UV-Vis spectra and absorption parameters using the time-dependent ZINDO/S approach. Our findings indicate that all the compounds have enhanced absorptions in the visible light range, and their molecular orbital energies adopt the condition of sensitizers. However, all of the complexes except down spin states exhibit considerably charge spatial separation. The results suggest that the ZnP-C₆₀-oligo-PPEs triad can meet the necessary conditions of the sensitizer of dye-sensitized solar cells (DSSCs) in comparison with other counterparts and could be an optimum triad compound for potential application in photovoltaic devices.

Theoretical assessments on the interaction between amino acids and the g-Mg3N2 monolayer: dispersion corrected DFT and DFT-MD simulations

The interaction of a few amino acids (AAs) with the graphene-like magnesium nitride (g-Mg₃N₂) monolayer has been investigated with density functional theory (DFT) simulations. The Mg site was found to cause significant attraction with the polar active sites of AAs. Such AAs, are capable of producing electrostatics bonding with -48.012 (kcal mol^-1) of interaction energy for tyrosine. The good consistency of the DFT interaction energy with the second-order Møller-Plesset method was found. Furthermore, the DFT-MD simulation of the tyrosine/g-Mg₃N₂ system demonstrated that this host-guest system is stable at ambient conditions. The electronic structures and quantum molecular descriptors were calculated, and the results revealed that the g-Mg₃N₂ monolayer is sensitive to the interaction with AAs. Our first-principles outcomes suggest comprehensive visions into the functionalization of g-Mg₃N₂, and anticipate its applicability as an unprecedented nanovector for AAs. In addition, g-Mg₃N₂ nanosheets can be utilized as biosensors for biomolecules detection. These are very hopeful for promising biological and pharmaceutical applications of g-Mg₃N₂.

The effect of Sn on the physical and optical properties of (Se0.6As0.1Ge0.3)100-xSnx glasses

Chalcogenide glasses are significant materials for semiconducting and infrared imaging because of their infrared (IR) transparency. In the present study, Se-Ge-As based chalcogenide glasses with chemical composition of (Se_0.6As_0.1Ge_0.3)_100-x Sn_x doped with different amounts of Sn were prepared by conventional melting-quenching method. Physical properties of glasses were investigated by studying density and molar volume. Based on differential scanning calorimetry (DSC) results and density measurements, the binary role of Sn was proved. Fourier transform infrared spectroscopy (FT-IR) study of the samples approved presence of impurities. Using the UV-Vis spectra, optical properties including Fermi energy level, direct and indirect optical band gap and Urbach energy were determined. The results showed a decrease in density of glasses with the increase of Sn from 2 to 6 mol%. Increasing Sn in the glassy microstructure of samples provides a semiconducting character to Se based chalcogenide glass by reducing the direct and indirect optical band gaps of glass samples from 1.29 to 1.15 (eV) and 1.16 to 1.01 (eV), respectively.

DFT/TD-semiempirical study on the structural and electronic properties and absorption spectra of supramolecular fullerene-porphyrine-metalloporphyrine triads based dye-sensitized solar cells

In the present work density functional theory (DFT) and time-dependent semiempirical ZNIDO/S (TD-ZNIDO/S) methods have been used to investigate the ground state geometries, electronic structures and excited state properties of triad systems. The influences of the type of metal in the porphyrin ring, change in bridge position and porphyrine-ZnP duplicate on the energies of frontier molecular orbital and UV-Vis spectra has been studied. Geometry optimization, the energy levels and electron density of the Highest Occupied Molecular Orbital (HOMO) and the Lowest Unoccupied Molecular Orbital (LUMO), chemical hardness (η), electrophilicity index (ω), electron accepting power (ω⁺) were calculated using ZINDO/S method to predict which molecule is the most efficient with a great capability to be used as a triad molecule in solar industry. Moreover the light harvesting efficiency (LHE) was calculated by means of the oscillator strengths which are obtained by TD-ZINDO/S calculation. Theoretical studies of the electronic spectra by ZINDO/S method were helpful in interpreting the observed electronic transitions. This aspect was systematically explored in a series of C₆₀-Porphyrine-Metalloporphyrine (C₆₀-P-Mp) triad system with M being Fe, Co, Ni, Ti, and Zn. Generally, transition metal coordination compounds are used as effective sensitizers, due to their intense charge-transfer absorption over the whole visible range and highly efficient metal-to-ligand charge transfer. We aim to optimize the performance of the title solar cells by altering the frontier orbital energy gaps. The results reveal that cell efficiency can be enhanced by metal functionalization of the free base porphyrin. Ti-porphyrin was found to be the most efficient dye sensitizer for dye sensitized solar cells (DSSCs) based on C₆₀-P-Mptriad system due to C₆₀-Por-TiP complex has lower chemical hardness, gap energy and chemical potential as well as higher electron accepting power among other complexes. In addition, the performance of solar cells favors better with doubly and increasing the π conjugated of the bridge.

Optical and structural investigation on sodium borosilicate glasses doped with Cr2O3

In this work, Sodium borosilicate glasses with chemical composition of 60% SiO₂-20% B₂O₃-20%Na₂O doped with different contents of Cr₂O₃ were prepared by melting-quenching method. Physical, structural and optical properties of glasses were investigated by studying density and molar volume, Fourier Transform Infrared (FT-IR) Spectra and UV-visible absorption spectroscopy. The results showed an increase in density of glasses with the increase of Cr₂O₃ that can be due to addition of oxide with high molar mass. The optical absorption spectra of un-doped glass reveals UV absorption due to trace iron impurities with no visible band however Cr₂O₃ doped glasses shows absorption in visible range that are characteristic. Increasing of Cr³⁺ ions in the glassy microstructure of samples provides a semiconducting character to Sodium borosilicate glass by reducing the direct and indirect optical band gaps of glass samples from 3.79 to 2.59 (ev) and 3.36 to 2.09 (ev), respectively. These changes could be attributed to the role of Cr³⁺ ions as the network former which asserts improvement of semiconducting behavior in presence of Cr₂O₃.

Estimation of influenza and severe acute respiratory illness incidence (burden) in three provinces of the Islamic Republic of Iran, 2012 and 2013

There are few estimates of influenza burden in the WHO Region for the Eastern Mediterranean. In this study we estimated the burden of severe acute respiratory infection (SARI) and influenza-associated SARI (F-SARI) in selected provinces of Islamic Republic of Iran, the trends of SARI and confirmed cases of influenza (F-SARI) over 12 months (seasonality), and the age groups most at risk. Using the electronic Iranian influenza surveillance system and data of cases in sentinel hospitals of 3 selected provinces, we estimated the monthly trend (seasonality) of incidence for SARI and F-SARI, overall incidence of SARI and F-SARI and their disaggregation by age with the aid using the Monte Carlo technique. The age groups most at-risk were children aged under 2 years and adults older than 50 years.

Anemia Outcome After Laparascopic Mini Bypass : Analysis of 107 Consecutive Patients

BACKGROUND

The prevalence of obesity has dramatically increased globally. Weight loss procedures are known to be an effective and reliable method with relatively low complication rate and satisfactory results. Laparoscopic mini-gastric bypass (LMGB) is known as a modified Mason loop procedure with compatible results to laparoscopic Roux-en-Y gastric bypass (LRYGB), and is believed to have even less complication rate. Despite adequate and meticulous supplement therapy, anemia is one of the challenges in patients undergoing LMGB. Thus, we aimed to review the prevalence and severity of anemia in patients undergoing LMGB.

METHOD

A prospectively-maintained database of patients referring to Hazrat Rasoul Akram hospital who underwent LMGB from December 2013 to October 2014 was reviewed retrospectively.

RESULTS

A total of 113 consecutive patients were included in the study. The mean age was 38.7 ± 9.8 years. Mean Body mass index (BMI) was 45.5 ± 6.1 kg/m2 preoperatively and 36.7 ± 5.5 kg/m2 and 33.0 ± 5.3 kg/m2 three and six months after the procedure, respectively. (P = 0.001) Mean excess body weight loss after the procedure was 20% and 53% at three and six months post operatively. Serum hemoglobin (Hb) level decreased significantly in three months (P = 0.036) and remained unchanged in six months compared to 3-month (P = 0.385). Vitamin B12 level increased significantly in three months (P = 0.010) and then decrease in six months to the preoperative level (P = 0.889).

CONCLUSION

LMGB is a safe, feasible and an effective alternative weight loss procedure. Simply, anemia can be prevented by utilizing therapeutic dose of multivitamin in patients who underwent this procedure.

[Stem cell derived therapy for cutaneous radiation exposure]

Radiation injury to skin results in a variety of deterministic effects including inflammatory reactions and cell depletion leading to distinct clinical symptoms following a defined time pattern. Therapeutic approaches are still limited, a complete restitution of affected areas is so far impossible. In the last few years increasing experimental knowledge about acquisition and administration of autologous stem cells also in the field of radiation injuries has been obtained. Evidence reviewed in this article shows that the beneficial effects of stem cell transplantation are not necessarily due to the replacement of damaged cells by transplanted cells but most probably due in the most part to a paracrine effect. Transplanted cells secrete bioactive factors that initiate the stimulation of the host stem cells to regenerate the damaged tissues. Transplanted stem cells produce trophic factors which aid the systemic healing of the victims. Furthermore, administration of stem cell secretomes in the form of conditioned media containing microvesicles or exosomes can be as effective as administering the stem cells. This hypothesis is supported by findings that cell-free derivatives from hMSCs were useful for wound healing purposes and could circumvent the need for intact cells. Furthermore, the beneficial effect of MSC injection on reperfusion and tissue damage in a mouse model of hind limb ischemia could be attributed to paracrine mechanisms with local release of arteriogenic cytokines. Further evaluation of the paracrine potential of autologous stem cells may open new means for treatment of acute as well as chronic sequelae of cutaneous radiation injuries.

Variation in amino acid digestibility of rapeseed meal studied in caecectomised laying hens and relationship with chemical constituents

1. The objectives were to study the variation in amino acid (AA) digestibility of rapeseed meal in laying hens and to investigate whether the variation in AA digestibility can be explained by chemical constituents of the rapeseed meal. Nine rapeseed meals from different processing plants operating in Germany were used. The crude protein and crude fibre concentrations of the meals ranged from 367 to 410 and 137 to 175 g/kg dry matter (DM), respectively. The concentrations of total glucosinolates varied between 5.1 and 12.9 mmol/kg DM. Each meal was included in one of the experimental diets at an inclusion level of 200 g/kg at the expense of maize starch. 2. A total of 16 Lohmann Brown laying hens were used for this experiment and were surgically caecectomised. They were housed individually in metabolism cages. Each of the 10 diets was fed to at least 6 hens in 4 periods of two weeks duration. Excreta were collected during the last 5 d of each period. The digestibility coefficient of AA was calculated for each diet. The digestibility of the rapeseed meals was calculated by multiple linear regression analysis. 3. Mean essential AA digestibility of rapeseed meals varied between 0.78 and 0.84. Among the essential amino acids, the ighest level of digestibility was found for arginine (0.88) and methionine (0.87), and the lowest for lysine (0.74) and threonine (0.75). The highest variation between rapeseed meals in digestibility was found for threonine (0.68 to 0.79) and lysine (0.68 to 0.78). The concentration of neutral detergent insoluble nitrogen of the rapeseed meals was negatively correlated with the digestibility of lysine, but was not significantly correlated with digestibility of any other AA. Glucosinolate concentration was significantly correlated with valine digestibility. 4. Multiple regression analysis showed that the concentrations of crude protein and ash together were the major factors considered to explain variation in digestibility of essential AA. Additional consideration of neutral detergent insoluble nitrogen and total glucosinolates improved the goodness of fit only marginally and was unlikely to be of practical significance.

Spectrophotometric complexation of cephalosporins with palladium (II) chloride in aqueous and non-aqueous solvents

The complexation reaction of cephalosporins namely cefotaxime (CTX), cefuroxime (CRX), and cefazolin (CEFAZ) with palladium (II) ions have been studied in water and DMF in 25 °C by the spectrophotometric methods. The method is based on the formation of yellow to yellowish brown complex between palladium (II) chloride and the investigated cephalosporins in the presence of sodium lauryl sulfate (SLS) as surfactant. The complexation process was optimized in terms of pH, temperature and contact time. The stoichiometry of all the complexes was found to be 2:1 (metal ion/ligand) for CTX, CRX, and 1:2 for CEFAZ. The stoichiometry of palladium (II)-cephalosporins was estimated by mole ratio and continuous variation methods and emphasized by the KINFIT program. These drugs could be determined by measuring the absorbance of each complex at its specific λmax. The results obtained are in good agreement with those obtained using the official methods. The proposed method was successfully applied for the determination of these compounds in their dosage forms.

Optical properties and structural evaluation of Li2O-Al2O3-SiO2-TiO2 glassy semiconductor containing passive agent CeO2

In the present work, the effect of CeO(2) as the passive agent on glassy structure of Li(2)O-Al(2)O(3)-SiO(2)-TiO(2) (LAST) material for production of a new amorphous semiconductor has been investigated. Optical properties and vibrational spectroscopy of the samples have been studied using UV-Vis and FTIR absorption spectra, respectively. Accordingly, structural variations of 0-1.5% CeO(2):LAST glasses were evaluated by calculation of density, molar volume, Urbach band tailing, direct and indirect optical band gaps, Fermi energy level and metallization criterion. Eventually for the analysis of the variation of energy level in presence of passive agent CeO(2), Licciardello's model for glassy semiconductors was utilized. Results of the investigation illustrates that while Ce(3+) ions could be regarded as the color agents due to spin allowed f-f transition, Ce(4+) ions might have a destructive influence on negative-U centers (color centers) of the glass and hence, reduce the recombination centers in the band gap of the glass.

Optical band gap and spectroscopic study of lithium alumino silicate glass containing Y3+ ions

The effect of different amounts of Y2O3 dopant on lithium alumino silicate (LAS) glass has been studied in this work. Glasses having 14.8Li2O-20Al2O3-65.2SiO2 (wt%) composition accompanied with Y2O3 dopant were prepared by normal melting process. In order to calculate the absorption coefficient of samples, transmittance and reflectance spectra of polished samples were measured in the room temperature. Optical properties i.e. Fermi energy level, direct and indirect optical band gaps and Urbach energy were calculated using functionality of extinction coefficient from Fermi-Dirac distribution function, Tauc's plot and the exponential part of absorption coefficient diagram, respectively. It has been clarified that variation in mentioned optical parameters is associated with the changes in physical properties of samples i.e. density or molar mass. On the other hand, increasing of Y3+ ions in the glassy microstructure of samples provides a semiconducting character to LAS glass by reducing the direct and indirect optical band gaps of glass samples from 1.97 to 1.67 and 3.46 to 2.1 (eV), respectively. These changes could be attributed to the role of Y3+ ions as the network former in the track of SiO4 tetrahedrals.

Application of a novel method for optimization of bioemulsan production in a miniaturized bioreactor

A novel and economical method was used to optimize bacterial growth and bioemulsan production. Acinetobacter calcoaceticus PTCC 1641 was applied in an innovated synthetic medium comprised whey and mineral salt medium (MSM) in ratio of 1:1 in a shaken flask bioreactor. The optimum inoculum size, shaking frequency rate and filling volume (V(L)) using ventilation flasks were investigated that resulted in 5 vol.%, 300 rpm and 15 ml), respectively. The surface tension decreased around 48% during bioemulsan production. Due to determine bioemulsan properties, the reliability of blood agar method was confirmed as well.

Comparison of amino acid digestibility determined prececally or based on total excretion of cecectomized laying hens

This study investigated the possibility of using cecectomized laying hens for the determination of amino acid (AA) digestibility of protein sources as an alternative to measurements made at the terminal ileum. Toasted soybeans and corn gluten meal were used as test protein sources. A low-protein basal diet was based mainly on corn, wheat gluten, and cornstarch. In 4 other diets toasted soybeans or corn gluten meal were included each at 15% or 30% at the expense of cornstarch, so that the changes in the AA concentrations of the diets resulted from the protein sources only. Titanium dioxide was used as the indigestible marker. In experiment 1, two hundred ten 18-wk-old pullets were used. Digesta from the posterior 2-thirds of the intestine between Meckel's diverticulum and 2 cm anterior to the ileo-ceca-colonic junction was obtained from killed hens. In experiment 2, fourteen cecectomized hens were used. They were kept individually, and excreta were quantitatively collected. The apparent digestibility of AA was calculated for each diet. Linear regression analysis was used to calculate AA digestibility for the 2 protein sources. Across all diets, apparent AA digestibility was significantly higher in experiment 2 than in experiment 1. However, AA digestibilities of the 2 protein sources were not different between both experiments. Differences in AA digestibility between the protein sources were not significant in experiment 1, but in experiment 2 significant differences between the protein sources were detected for some AA due to a lower standard error of estimate. It was concluded that AA digestibility of protein sources for laying hens can be evaluated based on quantitative excreta collection with cecectomized hens using the regression approach. This needs fewer animals than the determination of digestibility at the terminal ileum. Differences between protein sources are easier to detect because of the lower standard error of estimate.

Effect of ileum segment and protein sources on net disappearance of crude protein and amino acids in laying hens

1. This study investigated the net disappearance of crude protein (CP) and amino acids (AA) from soybean meal and rapeseed meal in different sub-sections of the ileum of hens. A basal diet was used and in another 4 diets, maize starch contained in the basal diet was replaced with soybean meal or rapeseed meal at 140 and 280 g/kg so that changes in dietary AA concentrations resulted from the oilseed meals only. 2. A total of 250 Lohmann Brown pullets were used for this experiment at 20 weeks old and given one of the 5 diets for 7 d. The section between Meckel's diverticulum and 2 cm anterior to the ileo-caecal-colonic junction was taken after slaughtering the hens and cut into three sub-sections of equal length. Digesta were taken separately from each sub-section and then frozen. Net disappearance of AA and CP for the diets and the two protein sources was calculated based on standard equations and using a multiple linear regression approach. 3. Net disappearances of CP and all AA were significantly lower in the proximal sub-section than in the central and terminal sub-sections. Also, the net disappearance of CP and all AA from rapeseed meal was significantly lower in the proximal sub-section than in the central or terminal sub-sections. For soybean meal, only the net disappearances of arginine, aspartic acid, glutamic acid and phenylalanine were significantly lower in the proximal than in the terminal sub-section. No significant differences in the net disappearance of CP and AA were detected between protein sources within the central and terminal sub-sections or between the central and terminal sub-section within each protein source. Soybean meal had a significantly higher net disappearance of CP and AA (with the exception of cystine and methionine) than rapeseed meal in the proximal sub-section but these differences were not statistically significant in the central and terminal sub-sections. 4. Amino acids disappeared from the proximal region of the ileum. This needs consideration in standard approaches that are used for measuring AA digestibility. There is a variation in AA digestibility between soybean meal and rapeseed meal. The ranking of individual AA regarding their digestibility is different between the two oilseed meals.

Prevalence of hepatitis C virus infection and risk factors of drug using prisoners in Guilan province

This was a cross-sectional prevalence study to determine the prevalence of hepatitis C virus (HCV) and high-risk behaviours in drug abusers admitted to prison in Guilan province, northern Islamic Republic of Iran. Subjects were asked about risk behaviours for acquiring HCV and blood was drawn for HCV antibody testing using ELISA techniques. Of 460 inmates, the mean duration of drug use was 8.9 years; 51.7% were opium users and 18.3% heroin users. HCV risk behaviours were common in this population and 209 inmates (45.4%) were HCV antibody positive (88.9% of intravenous drug abusers). HCV-positive status was significantly associated with intravenous drug use, having skin tattoos and number of times in prison.

Modification of radiation-induced acute oral mucositis in the rat

PURPOSE

A new non-toxic drug (compound A) consisting of curcumin, alpha-tocopherol and sunflower oil was developed and its efficacy tested in the treatment of radiation-induced oral mucositis in the rat.

MATERIAL AND METHODS

Mature (12 weeks old, 200-225 g) female Sprague-Dawley rats were used. While under general anaesthesia, the tongues of the animals were slightly extended outside and a region of the underside of the tongue was irradiated in-situ with single doses of 2.27 MeV beta-rays from a 5-mm diameter 90Sr/90Y plaque. The dose-rate of the source was about 10 Gy min(-1) at the surface of the mucus membrane. Irradiations and subsequent assessment of the lesion were carried out under general anaesthesia maintained by a 1.5% halothane/oxygen mixture. Six groups of animals were irradiated with single doses of 13.5, 15.0, 16.5 or 18Gy. One subgroup (radiation only) received no further treatment, while the other five groups received 0.5 ml day(-1) of either compound A, sunflower oil, alpha-tocopherol, curcumin or water containing 10% ethanol by oral gavage until the end of experiments. Mucosal ulceration (erosion of mucosal epithelium) was considered as an end-point. From the day after irradiation until any acute radiation-induced oral mucosal lesion had healed, the tongues of the animals were assessed daily for the presence of radiation-induced mucositis (mucosal ulceration). Quantal data for the incidence of radiation-induced mucositis were analysed using logit analysis and a dose-modification factor was obtained.

RESULTS

There was a modest increase in ED50, the dose expected to cause mucositis in 50% of the animals after both alpha-tocopherol and sunflower oil were administered. This resulted in dose-modification factors of 1.05. While curcumin treatment resulted in a dose-modification factor of 1.09. Compound A significantly reduced the incidence of radiation-induced mucositis with a statistically significant dose-modification factor of 1.2 +/- 0.1.

CONCLUSIONS

Curcumin and other components of compound A appeared to be effective in the prevention of radiation-induced oral mucositis. However, the overall effect observed with the combination drug (compound A) appeared greater than additive.

Focused ultrasound (HIFU) induces localized enhancement of reporter gene expression in rabbit carotid artery

The development of accurate, safe, and efficient gene delivery remains a major challenge towards the realization of gene therapeutic prevention and treatment of cardiovascular diseases. In this study, we investigated the ability of high-intensity focused ultrasound (HIFU), a form of mechanical wave transmission, to act as a noninvasive tool for the enhancement of in vivo gene transfer into rabbit carotid arteries. Segments of the common carotid arteries of New Zealand white rabbits were isolated and infused with plasmid DNA encoding the reporter beta-galactosidase either with or without the addition of ultrasound contrast agent consisting of small (approximately 2-5 microm) gas-filled human albumin microspheres to augment cavitation. Infused arteries were exposed to pulsed ultrasound for 1 min (frequency 0.85 MHz, burst length 50 ms, repetition frequency 1 Hz, duration 60 s, peak pressure amplitude of 15 MPa). At 6.3 MPa, HIFU enhanced gene expression eight-fold, and 17.5-fold in the presence of contrast. We found increasing amounts of beta-galactosidase expression in the carotid vessel with increasing pressure amplitude. This dose-response relation was present with and without contrast. Without contrast, no vessel damage was detected up to 15 MPa, while the addition of contrast induced side effects above a threshold of 6.3 MPa peak pressure. The entire procedure was feasible and safe for the animals, and the results suggest that HIFU has the potential to assist in the noninvasive spatial regulation of gene transfer into the vascular system.

Evidence for humoral effects on the radiation response of rat foot skin

The influence of perturbation of the physiologic state of the whole body on the outcome of radiation exposure has been examined in a rat foot model. Irradiation was carried out using 60Co gamma-rays. Moist desquamation was used as an endpoint. Rats were given a priming dose of 2 Gy, 4 Gy or 7 Gy to their whole body except their hind feet (partial body priming dose). After a variable time period both hind feet of these animals were irradiated with graded doses of 60Co gamma-rays. The incidence of moist desquamation in the irradiated feet of these animals was compared with the incidence of moist desquamation in animals that had not received the initial partial body priming dose. It was noticed that the incidence of moist desquamation in the rat foot skin of animals that received 7 Gy partial body priming dose 4 h prior to irradiation of their hind feet was significantly less than moist desquamation in control animals. The ED(50) value of 22.53+/-0.16 Gy for moist desquamation of the foot skin of control animals was significantly lower (p<0.01) than the value of 25.25+/-0.29 Gy obtained for animals that received a partial body priming dose of 7 Gy 4 h prior to irradiation of their hind feet. It was concluded that the response of rat foot skin to radiation was not purely the result of epidermal stem cell kill and that it can be modified by alterations in the overall physiological state of the animal's body brought about by a priming dose to the whole of the animal's body except the hind feet.

Modification of radiation myelopathy by the transplantation of neural stem cells in the rat

In a novel approach, neural stem cells were transplanted to ameliorate radiation-induced myelopathy in the spinal cords of rats. A 12-mm section of the cervical spinal cord (T2-C2) of 5-week-old female Sprague-Dawley rats was locally irradiated with a single dose of 22 Gy of (60)Co gamma rays. This dose is known to produce myelopathy in all animals within 6 months of irradiation. After irradiation, the animals were subdivided into three groups, and at 90 days after irradiation, neural stem cells or saline (for controls) were injected into the spinal cord, intramedullary, at two sites positioned 6 mm apart on either side of the center of the irradiated length of spinal cord. The injection volume was 2 microl. Group I received a suspension of MHP36 cells, Group II MHP15 cells, and Group III (controls) two injections of 2 microl saline. All rats received 10 mg/kg cyclosporin (10 mg/ml) daily i.p. to produce immunosuppression. All animals that received saline (Group III) developed paralysis within 167 days of irradiation. The paralysis-free survival rates of rats that received transplanted MHP36 and MHP15 cells (Groups I and II) were 36.4% and 32% at 183 days, respectively. It was concluded that transplantation of neural stem cells 90 days after irradiation significantly (P = 0.03) ameliorated the expression of radiation-induced myelopathy in the spinal cords of rats.

Protocol for X-ray dosimetry in radiobiology

PURPOSE

To harmonize X-ray dosimetry in radiobiology to allow a direct comparison of radiobiological studies performed at institutes cooperating within the framework of the European Late Effects Project Group (EULEP).

MATERIALS AND METHODS

The 1985 EULEP protocol for X-ray dosimetry and exposure arrangements employed for studies of late somatic effects in mammals required serious revision, e.g. due to the replacement of calibration of dosemeters in terms of exposure by calibration in terms of air kerma free-in-air. An action group established by EULEP and the European Radiation Dosimetry Group (EURADOS) updated the 1985 protocol.

RESULTS

The new EULEP-EURADOS protocol for X-ray dosimetry in radiobiology including the code of practice for irradiation of small animals and related dosimetry. The present protocol includes the changes in calibration procedures and dosimetric concepts for irradiation with medium energy X-rays since 1985. Accuracy and precision are replaced by the concept of combined (standard) uncertainty. The revised supplements provide more detailed background information. New appendices contain definitions of general terms used for measurements and mathematical expressions of the relative variances.

CONCLUSION

Adherence to the present protocol will result in improved dosimetry and facilitates the comparison of results of radiobiological experiments obtained at different institutes.

Boron neutron capture therapy: effects of split dose and overall treatment time

New clinical protocols are being developed that will entail the administration of considerably higher doses of the boron delivery agent boronophenylalanine (BPA) than those in current clinical use. Fractionation (2 or 4 fractions) of BPA mediated boron neutron capture therapy (BNCT) is also under consideration at some clinical centres. Given the considerably higher infusion volumes that will be entailed in the delivery of BPA in the new high dosage protocols, there will be a requirement to extend the gap between fractions to 2 or more days. In order to assess the effects of a 2 fraction protocol on the therapeutic efficacy of BPA mediated BNCT, a series of split dose irradiations (two equal fractions) were undertaken using the rat intracranially implanted 9L gliosarcoma model. A single dose exposure to BPA mediated BNCT of 3.0 Gy resulted in long term survival levels of 50%. Survival levels increased to 71% and 77% with a 3 and 5 day gap between dose fractions (two equal fractions), respectively, using the same total dose. A further increase in the time interval between dose fractions to 7 days resulted in a reduction in survival to 36%. However, there was no significant difference between the single dose and the 3, 5 and 7 day survival data (P > 0.1) The difference between the 5 and 7 day split dose survival data was of border-line significance (P = 0.05). It is anticipated that mucositis, could become a potential problem in future BNCT clinical protocols involving higher doses, larger field sizes or multiple fields. The potential sparing of the oral mucosa, due to repopulation during the interval between the two fractions, was investigated using a series of split dose BPA mediated BNC irradiations. The ventral surface of the rat tongue was utilised as a model for oral mucosa. The ED50 (50% incidence) values for the ulceration end point were 3.0+/-0.1, 3.2+/-0.1, 3.0+/-0.1 and 3.6+/-0.1 Gy, for 3, 5, 7 and 9 day splits between doses, respectively. It is evident from this data that there were no significant changes in the ED50 (p < 0.001) until the 9 day dose split, when the ED50 value was 20% higher than the ED50 value after a 7 day split. It was concluded that the two fraction BNCT protocol, with dose splits of up to 5 days, did not diminish the therapeutic response of the rat 9L gliosarcoma, when compared with a single dose BNCT protocol. Tolerance of the oral mucosa to BNC irradiation was not increased until there was a 9 day gap between fractions. However, the beneficial effects of dose sparing at this time interval between doses, would probably be counteracted by a reduction in the therapeutic effectiveness of the BNCT modality, due to repopulation of tumour clonogens between doses.

Effects of Lipochromin and Levosinum in the modulation of radiation-induced injury to pig skin

Pig skin was used as a model to study the effectiveness of two topically applied creams, Lipochromin and Levosinum, in modifying the development of both early and late radiation damage to pig skin. Irradiated skin sites that received daily topical application of Levosinum or Lipochromin after exposure were compared with sites on the contralateral flank of the same animal that received irradiation only. Irradiation was with graded doses of 90Sr/90Y beta-rays. Incidence of moist desquamation (acute) and ischaemic dermal necrosis (late) were used as end-points. The latency period for the development of moist desquamation and its healing time was also assessed. The latency period for the development of moist desquamation in this model ranged from 4.00-6.75 weeks. There was no significant difference between the cream treatment and control sites. Application of Levosinum shortened the healing time of moist desquamation at each dose level by 5-10 days. In three out of four dose levels used, this shortening of the healing time was statistically significant (p < 0.03). Treatment with these topical applications also reduced the incidence of late dermal necrosis and increased the ED50 values for the incidence of dermal necrosis. This increase in ED50 values was equivalent to a dose modification factor of 1.11-1.13.

Role of the adenomatous polyposis coli gene product in human cardiac development and disease

Expressed sequence tag (EST) and digital Northern analyses of human fetal, adult, and hypertrophic heart cDNA libraries revealed ESTs with high homology to adenomatosis polyposis coli (APC) and its associated protein, beta-catenin, as well as their differential expression. Thus, we hypothesize that the APC/beta-catenin pathway may play a role in cardiac development and disease. Reverse transcriptase-polymerase chain reaction analysis exhibited a higher APC expression in adult compared with fetal and hypertrophic heart but no significant difference in beta-catenin mRNA level. However, beta-catenin protein level was higher in fetal and hypertrophic heart compared with adult heart, suggesting the post-translational regulation of beta-catenin by APC in the cardiovascular system. In vitro antisense inhibition of APC resulted a higher beta-catenin protein expression leading to an incomplete myotube formation, suggesting APC/beta-catenin pathway involvement in myotube development. Western blot analysis further reveals three novel isoforms, APC-F, APC-A, and APC-D, ubiquitously expressed in fetal, adult, and hypertrophic heart, respectively. Isoform switching during development and disease pathogenesis suggests functionally distinct roles for each isoform. These data (i) demonstrate the usefulness of genome-based expression analysis for rapid discovery of differentially expressed genes, (ii) implicate the APC/beta-catenin pathway in the cardiovascular development, and (iii) demonstrate APC isoform switching during cardiac development and disease.

Boron microlocalization in oral mucosal tissue: implications for boron neutron capture therapy

Clinical studies of the treatment of glioma and cutaneous melanoma using boron neutron capture therapy (BNCT) are currently taking place in the USA, Europe and Japan. New BNCT clinical facilities are under construction in Finland, Sweden, England and California. The observation of transient acute effects in the oral mucosa of a number of glioma patients involved in the American clinical trials, suggests that radiation damage of the oral mucosa could be a potential complication in future BNCT clinical protocols, involving higher doses and larger irradiation field sizes. The present investigation is the first to use a high resolution surface analytical technique to relate the microdistribution of boron-10 (10B) in the oral mucosa to the biological effectiveness of the 10B(n,alpha)7Li neutron capture reaction in this tissue. The two boron delivery agents used clinically in Europe/Japan and the USA, borocaptate sodium (BSH) and p-boronophenylalanine (BPA), respectively, were evaluated using a rat ventral tongue model. 10B concentrations in various regions of the tongue mucosa were estimated using ion microscopy. In the epithelium, levels of 10B were appreciably lower after the administration of BSH than was the case after BPA. The epithelium:blood 10B partition ratios were 0.2:1 and 1:1 for BSH and BPA respectively. The 10B content of the lamina propria was higher than that measured in the epithelium for both BSH and BPA. The difference was most marked for BSH, where 10B levels were a factor of six higher in the lamina propria than in the epithelium. The concentration of 10B was also measured in blood vessel walls where relatively low levels of accumulation of BSH, as compared with BPA, was demonstrated in blood vessel endothelial cells and muscle. Vessel wall:blood 10B partition ratios were 0.3:1 and 0.9:1 for BSH and BPA respectively. Evaluation of tongue mucosal response (ulceration) to BNC irradiation indicated a considerably reduced radiation sensitivity using BSH as the boron delivery agent relative to BPA. The compound biological effectiveness (CBE) factor for BSH was estimated at 0.29 +/- 0.02. This compares with a previously published CBE factor for BPA of 4.87 +/- 0.16. It was concluded that variations in the microdistribution profile of 10B, using the two boron delivery agents, had a significant effect on the response of oral mucosa to BNC irradiation. From a clinical perspective, based on the findings of the present study, it is probable that potential radiation-induced oral mucositis will be restricted to BNCT protocols involving BPA. However, a thorough high resolution analysis of 10B microdistribution in human oral mucosal tissue, using a technique such as ion microscopy, is a prerequisite for the use of experimentally derived CBE factors in clinical BNCT.

The pig as a model for the study of radiation effects on the lung

PURPOSE

The treatment of thoracic malignancies is frequently limited by the 'tolerance' of normal lung tissue. In order to learn more about the factors that influence lung tolerance an animal model that closely mimics the clinical exposure situation is required. The lungs of pigs are similar to those of man in a variety of ways and the animal's size permits the irradiation of partial tissue volumes comparable with those used clinically; very rarely in man is the whole lung irradiated. In this report, the available data for the effects of irradiation on pig lung are reviewed as they relate to the key issues in radiotherapy.

RESULTS

The dose-effect relationships for exposure to single doses indicate that for a significant impairment in both early and late lung function and for the histological detection of fibrosis, the dose-related changes in pig and man are similar. Studies with dose-fractionation using X-rays indicate a large dependence of the iso-effective dose on fraction number and fraction size, and the parameters obtained were not significantly influenced by the time of assessment after irradiation. A simple power-law function fitted the whole data set better than the linear-quadratic model, with a fraction number exponent (N) of 0.44+/-0.06 for treatments given in 1-30 fractions. The alpha/beta values ranged from 0.6 to 4.86 Gy, tending to increase with the length of the follow-up period; however; the majority of these alpha/beta values were not significantly different from zero at the 5% level. Studies of the effect of changes in the volume of lung tissue irradiated indicated the need for care in the use of the terms 'tolerance' and 'iso-effective' dose. Doses that were iso-effective for the severity of regional damage were not matched by those for total lung function. The same level of damage in a small volume compared with a large volume had less effect, i.e. was better tolerated in terms of changes in total lung function.

CONCLUSION

Iso-effective doses in pig and humans are lower than those for the more common laboratory animal species. This observation may be related to the differences in anatomical structure of the lungs in the different species.

Apoptosis-related genes expressed in cardiovascular development and disease: an EST approach

Apoptosis (programmed cell death) is an important process which, in conjunction with cell proliferation, maintains cell number homeostasis. Although apoptosis has been more extensively investigated in other tissues [1,2], only recently has this process been suspected as a significant contributor to both disease and normal development of the cardiovascular system [3-6]. Grasping a comprehension of the underlying genetic mechanisms of apoptosis is especially crucial considering that cardiac myocytes irreversibly exit the cell cycle and thus fail to proliferate during pathological conditions. Despite great strides in understanding the molecular pathways of apoptosis, there still remain numerous questions to be answered. Identifying key genes that are involved in the regulatory process of apoptosis in the cardiovascular system will serve as a basis for creating more effective therapeutic treatments in cardiovascular disease and provide an understanding of how cardiac development is modulated. This review provides a brief summary of recent data implicating genes that may be involved in apoptosis in the cardiovascular system. It also outlines the continued usefulness of large-scale generation of expressed sequence tags (ESTs) to establish expression profiles from the cardiovascular system and as a means of identifying potentially significant apoptotic regulators previously characterized in other tissues but not as yet in the cardiovascular system.

Time- and dose-related changes in the thickness of skin in the pig after irradiation with single doses of thulium-170 beta particles

Time-related changes in skin thickness have been evaluated in the pig using a noninvasive ultrasound technique after exposure to a range of single doses of 0.97 MeV beta particles from (170)Tm plaques. The reduction in relative skin thickness developed in two phases; the separation into two phases was statistically justified only after 120 Gy (P = 0.04). The first phase was between 12 weeks and 24 weeks after irradiation. No further changes were seen until 48-60 weeks after irradiation, when a second phase of skin thinning was observed. No further changes in relative skin thickness were seen in the follow-up period of 104 weeks. The timing of these phases of relative skin thinning was totally independent of the radiation dose; however, the severity of each phase of radiation-induced skin thinning was related to the dose. The pattern of changes was similar to that reported previously after irradiation with 2.27 MeV beta particles from (90)Sr/(90)Y, but the degree of dermal thinning was less for a similar skin surface dose. From a comparison of the depth-dose distribution of the beta particles from the two radionuclides, it was concluded that the target cell population responsible for both the first and second phase of skin thinning in pig skin after irradiation may be located at approximately 800 microm depth. This corresponds to an area in the reticular dermis in pig skin and may be the appropriate site at which to measure the average dose to the dermal tissue.

How valid is the assumption of equal effect per fraction?

BACKGROUND AND PURPOSE

The validity of the assumption of equal biological effect with dose per fraction in fractionated radiotherapy has been examined for the acute skin reaction in a rat foot model using a variable number of 2-Gy daily fractions followed by graded top-up doses.

MATERIAL AND METHODS

Mature female rats were used. Both hind feet of each rat were irradiated with a range of fractionated and top-up doses of 60Co gamma-rays. The dose-related incidence of moist desquamation was used as an end-point. Quantal data for the incidence of moist desquamation were analysed using probit analysis and ED50 (+/-SE) values were obtained. The results were also compared with predicted values obtained from the application LQ-model.

RESULTS

After a single 2-Gy fraction followed by top-up doses 24 h later, the dose effect curve for the top-up doses used was shifted to lower doses as expected and the ED50 for moist desquamation of 19.78 +/- 0.13 Gy was 1.16 Gy less than the ED50 of 20.94 +/- 0.15 Gy for large single dose exposure alone. This implied that only approximately 58% of the initial 2-Gy fraction was effective, and the rest was repaired within a 24-h interval between the 2 Gy and top-up doses. However, after two or three 2-Gy daily fractions the dose effect curves for the subsequent top-up doses moved to the higher doses again and the ED50 for top-up dose increased to 20.33 +/- 0.21 and 20.75 +/- 0.11 Gy, respectively. A further increase in the number of 2-Gy daily fractions shifted the dose effect curves for the top-up doses to lower doses and ED50 values for the top-up doses decreased progressively.

CONCLUSIONS

The findings were not in keeping with values predicted based on the assumption of equal effect per fraction and could not be explained by the use of a single alpha/beta ratio in the LQ-model.