Inter-comparison of absorbed dose rates for non-human biota

A number of approaches have been proposed to estimate the exposure of non-human biota to ionizing radiation. This paper reports an inter-comparison of the unweighted absorbed dose rates for the whole organism (compared as dose conversion coefficients, or DCCs) for both internal and external exposure, estimated by 11 of these approaches for selected organisms from the Reference Animals and Plants geometries as proposed by the International Commission on Radiological Protection. Inter-comparison results indicate that DCCs for internal exposure compare well between the different approaches, whereas variation is greater for external exposure DCCs. Where variation among internal DCCs is greatest, it is generally due to different daughter products being included in the DCC of the parent. In the case of external exposures, particularly to low-energy beta-emitters, variations are most likely to be due to different media densities being assumed. On a radionuclide-by-radionuclide basis, the different approaches tend to compare least favourably for (3)H, (14)C and the alpha-emitters. This is consistent with models with different source/target geometry assumptions showing maximum variability in output for the types of radiation having the lowest range across matter. The intercomparison demonstrated that all participating approaches to biota dose calculation are reasonably comparable, despite a range of different assumptions being made.

The astrocytes number in different subfield of rat's hippocampus in reference memory learning method

In this study with usage of morris water maze and reference memory technique, we used 10 male albino wistar rats. Five rats in control group and 5 rats in Reference memory group. After histological preparation, the slides were stained with PTAH staining for showing the Astrocytes. Present results showed significant difference in astrocytes number in CA1, CA2 and CA3 area of hippocampus between control and reference memory group. The number of astrocytes is increased in reference memory group. Then we divided the hippocampus to three parts: Anterior, middle and posterior and with compare of different area (CA1, CA2 and CA3) of hippocampus, we found that the increase of astrocytes number in posterior two-third of CA2 and CA3 is more than of it's number in the anterior one-third.

The similarity of astrocytes number in dentate gyrus and CA3 subfield of rats hippocampus

The dentate gyrus is a part of hippocampal formation that it contains granule cells, which project to the pyramidal cells and interneurons of the CA3 subfield of the hippocampus. Astrocytes play a more active role in neuronal activity, including regulating ion flux currents, energy production, neurotransmitter release and synaptogenesis. Astrocytes are the only cells in the brain that contain the energy molecule glycogen. The close relationship between dentate gyrus and CA3 area can cause the similarity of the number of astrocytes in these areas. In this study 5 male albino wistar rats were used. Rats were housed in large plastic cage in animal house and were maintained under standard conditions, after histological processing, The 7 microm slides of the brains were stained with PTAH staining for showing the astrocytes. This staining is specialized for astrocytes. We showed that the number of astrocytes in different (ant., mid., post) parts of dentate gyrus and CA3 of hippocampus is the same. For example, the anterior parts of two area have the most number of astrocytes and the middle parts of two area have the least number of astrocytes. We concluded that dentate gyrus and CA3 area of hippocampus have the same group of astrocytes.

Development of a methodology for assessing the environmental impact of radioactivity in Northern Marine environments

The requirement to assess the impacts of radioactivity in the environment explicitly and transparently is now generally accepted by the scientific community. A recently developed methodology for achieving this end for marine ecosystems is presented within this paper. With its clear relationship to an overarching system, the marine impact assessment is built around components of environmental transfer, ecodosimetry and radiobiological effects appraisal relying on the use of "reference organisms". Concentration factors (CFs), dynamic models and, in cases where parameters are missing, allometry have been employed in the consideration of radionuclide transfer. Dose conversion coefficients (DCCs) have been derived for selected flora and fauna using, inter alia, dose attenuation and chord distribution functions. The calculated dose-rates can be contextualised through comparison with dose-rates arising from natural background and chronic dose-rates at which biological effects have been observed in selected "umbrella" endpoints.

Distal esophagitis in patients with mustard-gas induced chronic cough

Although confounded by some factors such as medications or surgical complications, the relationship between esophageal pathology and pulmonary disorders has been the subject of many studies. The present study sought to investigate the said relationship in patients inflicted by respiratory disorders induced by mustard gas (MG). A case group of patients complaining of respiratory complications and chronic coughs following MG exposure, and a control group of patients with chronic coughs but without a history of MG exposure were studied. All the case and control subjects had symptoms of gastro-esophageal reflux disease. Chest high resolution tomography (HRCT) was performed to evaluate the existence of pulmonary disorders. Endoscopy and histological studies were carried out to determine the severity of esophagitis in both groups presenting with gastroesophageal reflux. Ninety male patients, who had met our criteria, along with 40 male control cases underwent the diagnostic procedures. The frequency of endoscopic esophagitis findings in the chemically exposed group was significantly higher than that in the control group (70.0%vs. 42.5%). A pathological evaluation revealed that the frequency of esophagitis in the cases was more than that in the controls (32.3%vs. 14.2%). Chest HRCT evaluation demonstrated that half the case group had more than 25% air trapping in expiratory films, mostly compatible with bronchiolitis obliterans (BO). In addition, they were suffering from asthma, chronic bronchitis and bronchiectasis. Bronchiolitis obliterans, along with other lung disorders, can be considered as contributors in the pathogenesis of esophagitis in MG exposed patients.

High incidence of tobacco streak virus in the tobacco fields of Iran

Currently the northern provinces of Iran (Mazandaran, Golestan and Gilan) are the main tobacco growing regions in the country and this crop has an special importance in the national economy. Three tobacco types including flue-cured (mainly Coker 347 and some Virginia E1), burley (Burley 21) and oriental (Basma 178-2) are presently grown in these regions. Epidemics of viral diseases have occurred during the recent years in many tobacco fields in these areas. The quality of tobacco products which is much important, is adversely affected by plant pathogens specially viruses. In a survey on the viruses of tobacco, the fields in these regions were inspected and leaf samples from symptomatic plants were collected. Some plants had one or more of the symptoms such as dentate leaf margin, thicker leaf tissue and necrotic areas on the stem. The samples were tested for TSV infection by the DAS-ELISA method (Clark and Adams, 1977) using polyclonal antibody (AS-0615, DSMZ, Germany). TSV was detected in more than 79% of all tobacco samples from these three provinces. The TSV infection level among the tested samples was 86.8% in Gilan (Rasht, Bazar-Jomeh and Talesh), 82.3% in Mazandaran (Behshahr, Sari, Neka and Sourak) and 71.8% in Golestan (Gorgan, Aliabad and Minoodasht). No significant difference was seen among the infection levels for the mentioned commercial varieties and also some other tested varieties such as C176, K326 and MN944. It seems that there is no resistance sources against this virus within these varieties. Also the results of tests for TSV were similar in two consecutive years (2004 and 2005). It should be added that not all of the TSV infected plants showed the stated symptom types. Many of the TSV infected samples had mixed infections with one or more other viruses such as TSWV, CMV, PVY and TMV and there was almost no sample with a single TSV infection. This is the first report on the occurrence and distribution of TSV in the tobacco fields of Iran, too.

Evaluating the efficiency of a TPIA method for the detection of two tobacco viruses

Field experiments are usually necessary for analyzing the efficiency of control methods, the resistance of varieties and many other virological studies. Such experiments generally include a large number of samples to be tested serologically. DAS-ELISA is a very accurate technique that has been widely used for identifying viral infections. For large numbers of plant samples, it takes a long time for the sample preparation, plate washing and other procedures. In this study, the efficiency of a simple and laborsaving TPIA (Tissue Print Immunoassay) method was evaluated for the identification of two important aphid-transmitted viruses (CMV and PVY) of tobacco fields in comparison with DAS-ELISA as the standard method. The leaf samples were collected from the fields of three commercial tobacco types (flue-cured, burley and oriental). Each sample was divided to two parts and each part was examined by one of the methods. DAS-ELISA was done based on the method described by Clark and Adams (1977). In TPIA, small parts of the leaf samples were rolled and then cut by a sterile sharp blade. The cut surface was gently printed on 1 cm2 blocks drawn on a nitrocellulose paper. Air dried paper was located first in 1% BSA for blocking the empty sites on paper, then in the buffer containing AP-conjugated polyclonal antibody for 3 h and finally in NBT-BCIP solution for color development. Between these stages, the paper was washed thoroughly (three times) by shaking in fresh washing buffer. The results of each sample were recorded and compared with those of DAS-ELISA. By considering DAS-ELISA as the reference method, the sensitivity of TPIA for the detection of PVY and CMV was 96.1% and 92.7%, respectively. The positive results by TPIA which were not detected positive by DAS-ELISA were regarded as false positive. These were 8 (out of 316 tested samples) for CMV and 6 (out of 204 samples) for PVY. Although the results of TPIA were not completely consistent with DAS-ELISA, it seems that this method can be used for some general studies. The most important advantages of this method were that it didn't need sample extraction and was done using only one antibody which was the conjugated antibody of each virus. This method gives more rapid results (within a day) in comparison with DAS-ELISA that needs more time.

Chronic topical administration of WIN-55-212-2 maintains a reduction in IOP in a rat glaucoma model without adverse effects

Glaucoma, one of the leading causes of blindness, is associated with high intraocular pressure (IOP) as a risk factor. The aim of this study was to examine both local and systemic effects of chronic topical administration of the synthetic CB1/CB2 agonist, WIN-55-212-2 and its potential to sustain ocular hypotension. WIN-55-212-2 (0.5%) or Tocrisolve, the vehicle, was administered topically three times daily to rats with surgically created glaucoma for 4 weeks, followed by a 1-week washout period. IOP, blood pressure and heart rate were measured weekly along with confocal microscopy and slit lamp biomicroscopy to detect ocular toxicity. IOP decreased rapidly by up to 47% in the WIN-55-212-2 treated group from 14.1+/-0.7 to 6.6+/-0.2 mmHg. The decrease was maintained during the treatment period. After the washout period, IOP (12.3+/-0.2 mmHg) was not different from baseline. In the contralateral eye, IOP showed a downward trend. Tocrisolve alone had no effect on IOP. No changes in blood pressure, heart rate or indicators of ocular toxicity were noted within either group. Topical application of WIN-55-212-2 significantly deceased IOP for duration of treatment. The decrease was sustained without the development of tolerance. Following cessation of therapy, IOP rapidly returned to baseline. No significant cardiovascular effects or ocular toxicity were noted during chronic topical therapy with either drug or vehicle.

Survival of the d-wave superconducting state near the edge of antiferromagnetism in the cuprate phase diagram

In the cuprate superconductor YBa2Cu3O6+x, hole doping in the CuO2 layers is controlled by both oxygen content and the degree of oxygen ordering. At the composition YBa2Cu3O6.35, the ordering can occur at room temperature, thereby tuning the hole doping so that the superconducting critical temperature gradually rises from 0 to 20 K. Here we exploit this to study the c-axis penetration depth as a function of temperature and doping. The temperature dependence shows the d-wave superconductor surviving to very low doping, with no sign of another ordered phase interfering with the nodal quasiparticles. The only apparent doping dependence is a smooth decline of superfluid density as T(c) decreases.

Observation of weak-limit quasiparticle scattering via broadband microwave spectroscopy of a d-wave superconductor

There has long been a discrepancy between microwave conductivity measurements in high temperature superconductors and the conductivity spectrum expected in the simplest models for impurity scattering in a d-wave superconductor. Here we present a new type of broadband measurement of microwave surface resistance that finally shows some of the spectral features expected for a d(x2-y2) pairing state. Cusp-shaped conductivity spectra, consistent with weak impurity scattering of nodal quasiparticles, were obtained in the 0.6-21 GHz frequency range in highly ordered crystals of YBa2Cu3O6.50 and YBa2Cu3O6.99.

Structure and diversification of the bovine immunoglobulin repertoire

Our understanding of the basis to immunoglobulin formation in cattle has benefited substantially from the application of molecular biology over the past decade. It is now established that both the lambda light chain and heavy chain repertoires are founded upon the frequent expression of single gene families and subgroups of segments which are of conserved sequence. It is likely that a functional kappa locus exists in the bovine genome but this isotype comprises as few as 5% of bovine light chains. Similarly, alternative but non-expressed V(H) gene families are present posing intriguing but unresolved questions about the regulation of immunoglobulin synthesis. The heavy chain frequently bears a third complementarity-determining region which is atypically long but the processes which expand this region of the reading frame and its contribution to the interaction with antigen remain matters of speculation. Opportunities exist to map the major immunoglobulin loci and to define the membership and sequence diversity of the gene families which dominate each repertoire. However, it is already evident that cattle cannot generate significant diversity from rearrangement and junctional imprecision alone. Elucidation of the mechanism(s), dynamics and tissue distribution of immunoglobulin diversification in cattle, thus, remain key challenges in this branch of veterinary immunology.

Measurement of luminal nitric oxide in bladder inflammation using a silicon balloon catheter: a novel minimally invasive method

OBJECTIVES

Nitric oxide (NO) measured in the gaseous phase has been shown to be a marker of inflammation in the urinary bladder. The NO content of air incubated in the bladder can be measured in an NO analyzer. The aim of our study was threefold: to evaluate whether NO can be measured in air incubated in a catheter balloon, to determine the optimal time of incubation, and to find the most suitable type of catheter.

METHODS

The NO concentration in air introduced directly into the bladder and into the catheter balloon was measured in patients with and without bladder infections. The air was incubated for 5 to 60 minutes. NO concentration in the bladder of patients with interstitial cystitis was also analyzed. The diffusion rate of NO through silicon and latex catheters was studied.

RESULTS

Elevated NO levels were detected in the urinary bladder in patients with bladder inflammation due to infection or interstitial cystitis. A marked increase in NO concentration was found after just 5 minutes of incubation and continued to rise for up to 20 minutes, both in air taken directly from the bladder and from the catheter balloon. The NO diffusion rate into the balloons of silicon catheters was high; the recovery rate in latex catheters was poor.

CONCLUSIONS

Measurement of NO concentration in a silicon balloon catheter inserted into the urinary bladder is a fast, convenient, and reliable method to detect inflammation.

Nitric oxide: a useful gas in the detection of lower urinary tract inflammation

PURPOSE

Luminal nitric oxide has been shown to be elevated in the bladder of patients with cystitis of various etiologies. We determine whether luminal nitric oxide can be used as a marker to differentiate inflammation, that is interstitial cystitis, from urgency, frequency, nocturia and pain due to noninflammatory disorders, such as outflow obstruction and neurogenic dysfunction.

MATERIALS AND METHODS

We measured luminal nitric oxide in the bladder of patients with urgency due to detrusor instability (6), outflow obstruction (7), sensory urge (19) and interstitial cystitis (8), and controls without urgency symptoms (11). Nitric oxide-free air was incubated in the bladder for 5 minutes and analyzed in a chemiluminescence nitric oxide analyzer.

RESULTS

There was a nearly 20-fold increase in mean bladder nitric oxide concentration in patients with interstitial cystitis (234+/-67 parts per billion) compared to those with detrusor instability (11+/-1), outflow obstruction (9+/-1) and sensory urgency (10+/-1), and controls (13+/-2).

CONCLUSIONS

Measurement of nitric oxide in air from the bladder is a simple, safe and fast method to differentiate urgency due to inflammation from neurogenic disorders or outflow obstruction. The simplicity of this method makes it potentially useful as a screening method for office use.

Clinical evaluation of resin-bonded prostheses: Rochette technique

Ninety patients, with a total of 90 resin-bonded prostheses placed in a private dental office from 1981 to 1991, were recalled for clinical evaluation of their restorations. Tissue condition, patient satisfaction, prosthesis failures by location and by sex of patient were assessed. Debondings occurred in both the mandibular and maxillary arches. In the present study, there were no gender-based differences in the rate of debonding and prostheses with more than two retainers were more likely to have problems.