Minimum Activity Concentration Research Articles

Natural radionuclide distribution and analysis of associated radiological concerns in rock samples from a rocky town (Dutsin-Ma) in the North-Western region of Nigeria

Natural radionuclides in rock samples, especially 226Ra (Radon), 232Th (thorium), and 40K (potassium), are the primary source of exposure to radiation for employees and the public, and their detection is critical for radiation safety. The gamma (γ) radiation from natural radionuclides was quantified using the γ-ray spectrometry method in twenty rock samples obtained from Dutsin-Ma, a rocky town in Nigeria's north-western region. The data obtained were used to estimate the radiological parameters and the excess lifetime cancer risk (ELCR). The results obtained show that the minimum activity concentrations of 40K, 232Th, and 226Ra are respectively 36.7 Bq/kg, 25.99 Bq/kg, and 11.59 Bq/kg, with their maximum values being 73.23 Bq/kg, 92.81 Bq/kg and 100.93 Bq/kg respectively. The average activity of 40K, 232Th, and 226Ra in the rock samples were found to be 73.5781±3.38 Bq/kg, 40.7848±3.32 Bq/kg, and 33.6616±3.58 Bq/kg respectively, which were all below the World average values of (33, 45 and 420) Bq/kg respectively. The ELCR was found to be 0.185±0.01, while the average absorbed dose rate, as well as the mean annual effective dose rate, were calculated to be 43.13±2.7 nGy/h and 0.015±0.003 mSv/y respectively. The outcomes for internal hazard, external hazard, annual absorbed and effective dose equivalent (ABEDE), alpha and gamma index values were below the maximum values allowed limits of 1 mSv/y for ABEDE and 1 for representative alpha & gamma index values, internal and external hazards as recommended by the International Commission on Radiological Protection (ICRP). This study shows that the radiation contamination of rock particles in Dutsin-Ma LGA does not pose much significant risk.

Uranium Concentrations Measurement in the Soil of Wasit Governorate

The aim of this study is to measure the uranium concentrations in soil samples taken from regions situated in Wasit governorate at depth(5-15)cm. The determination of uranium concentration in soil CR-39 Track detector. The nuclear reaction used a source of nuclear fission fragments U 235 92 (n , f) obtained by the bombardment of U 235 92 with thermal neutrons from (Am-Be) source which hasflux of (5 ×103 n cm-2 s-1). Radionuclide( U 235 92 ) was measured to all the zones of the study. The maximum and minimum activity concentration of ( U 235 92 ) were (3.75 ppm and 1.11 ppm) at the zones(A1)and (K5) respectively.

РАДИОНУКЛИДЫ В ВЕРХНЕМ СЛОЕ ПОЧВ ОСОБО ОХРАНЯЕМЫХ ПРИРОДНЫХ ТЕРРИТОРИЙ РОСТОВСКОЙ ОБЛАСТИ

The paper is devoted to the assessment of the features of the distribution of natural radionuclides (226Ra, 232Th, 40K) and artificial 137Cs in the upper soil layer of specially protected areas of the Rostov region. The activity concentration of radionuclides in the soil was measured by the gamma spectrometric method. The distribution of the artificial radionuclide 137Cs in the soils of the Rostov region is uneven. The minimum activity concentration of radiocesium is recorded in the Rostov nature reserve. It is shown that the arithmetic mean, median and modal values of the activity concentration of 137Cs are 21.7, 14.2 and 7.5 Bq/kg, respectively, and the arithmetic mean activity concentration of natural radionuclides in the soils of the protected areas of the Rostov region are 26, 9 Bq/kg for 226Ra, 27.0 Bq/kg for 232Th. These values can be used as background (reference) values in assessing the degree of influence of industry and urbanization on soil radioactivity.

226Ra, 228Ra and 40K as tracers of erosion and accumulation processes: A 3-year study on a beach with different sediment dynamics

The aim of this study is to analyse the role of natural radionuclides 226Ra, 228Ra, 40K and unsupported 210Pb (210Pbex), as erosion and accumulation process tracers. For this purpose, a complex system, including both the characteristic dynamics of a closed beach and those associated with a beach open to wave action, was studied. A 3-year study of monthly variation of 226Ra, 228Ra, 40K and 210Pbex was carried out at Las Canteras beach, on the Island of Gran Canaria (Spain), covering several erosion and accumulation periods. A correlation analysis, ANOVA test and Tukey’s Honestly Significant Difference (HSD) Test proved that the marine erosion and accumulation agents influenced the activity concentration values found for the different radionuclides. Moreover, the geochemical analysis of samples from maximum and minimum activity concentration values showed that the natural radionuclides studied could be suitable tracers for studying beach sediment dynamics in erosion and accumulation periods.

MEASUREMENT OF RADON ACTIVITY CONCENTRATION IN UNDERGROUND WATER OF BURETI SUB-COUNTY OF KERICHO COUNTY KENYA.

The activity concentration of radon in underground water of Bureti sub-county was measured using liquid scintillating counter device. The average radon activity concentration in all the water samples was 12.41Bql-1. The maximum and minimum activity concentrations of radon were 22.5 and 4.57Bql-1, respectively. In total, 53% of the total samples analysed had radon concentration levels above the US Environmental Protection Agency-recommended limit of 11.1Bql-1. The annual dose received by an individual as a result of waterborne radon was determined according to the United Nations Scientific Committee on the Effect of Atomic Radiation reports and was found to be 33.23𝜇Svy-1. All the samples recorded a value <100𝜇Svy-1 recommended by the World Health Organization and the European Union council.

Safe chemical repellents to prevent the spread of invasive ants.

The red imported fire ant, Solenopsis invicta, is one of the most dangerous invasive species in the world. Fire ants can spread by hiding among plant material and soil that are transported from infested areas in vehicles and vessels. Therefore, efficient repellents may be used to prevent fire ants from infesting transported goods. Although some fire ant repellants have been identified, novel, cost-effective and environmentally friendly materials for fire ant control are still needed. Recent studies with other model insects have suggested readily available, non-toxic alternatives (e.g., anthranilates) to commercial repellents. We measured the repellent effects of the food additives ethyl anthranilate and butyl anthranilate against nesting by fire ant workers, and the results demonstrated that extremely low concentrations of these compounds can prevent fire ant nesting in pots. The tested compounds remained active at concentrations < 100 µL/L, which is many times lower than the minimum active concentration of any other proposed compound, including the established insect repellent N,N-diethyl-3-methylbenzamide (DEET). These inexpensive chemicals are safely used by the food and cosmetics industries, and their high efficiency differentiates them as the most promising chemicals for use in preventing the spread of fire ants; thus, these chemicals should be evaluated for further potential applications. © 2018 Society of Chemical Industry.

Characteristics of the resistance of microorganisms to antimicrobial drugs

The resistance of microorganisms to antimicrobial drugs is an important problem of medicine. The aim – to study forming of the resistance to decamethoxine® (DCM®), decaminum (DC) and properties of microorganisms. In the study, a quantitative assessment of antimicrobial drugs was performed based on the activity index of the drug (AID), which shows the ratio of the working concentration of antiseptic to its minimum active concentration for a specific agent. The first indicator for determining the AID is derived from the instructions for the use of the drug, the relevant directories. Minimum inactivation concentration (MIC) values was determined experimentally in strains of the corresponding species that did not have contact with medicinal products. Microbiological studies on diphtheria rods, Staphylococcus albus and S. aureus, clinical strains of Candida albicans, which possessed typical tinctorial, morphologic, and cultural properties were carried out in this work. The effective concentrations of medicinal antimicrobial drugs decamethoxine®, decaminum, levorinum, nystatin were determined by means of the method of double serial dilutions. Conditions were defined for the formation of resistant forms of microorganisms (nutrient medium, microbial load, concentration of drugs). There was analyzed the resistance of Staphylococci, Corynebacterium diphtheria, Candida albicans drugs and the monitoring of the resistance of microorganisms to decamethoxine®, decaminum, levorinum, nystatin was carried out. According to the results of experimental study on the nutrient medium the slow forming of resistance in Staphylococci, C.diphtheria, C.albicans to DCM and DC were found. These studies showed a lack of cross-resistance of clinical strains of C.albicans to antimycotics DCM® and DC, on the one hand, and levorinum and nystatin on the other. Resistant to DCM of C.albicans were found to be susceptible to decaminum (3,9 μg/ml), levorinum (0,12 μg/ml) and nystatin (1,9 μg/ml). While forming the resistance to antimicrobial drugs changes of morphology with the formation of polymorphic cells have been established in microorganisms. The loss of biological activity of microorganisms due to changes in the activity of microbial cell enzymes during the formation of resistance was determined. The expediency of using DCM®, decaminum, levorinum, nystatin for prevention, treatment, overcoming of resistance in resistant variants of microorganisms to DCM®, decaminum.

Variation of natural radionuclides in non-ferrous fayalite slags during a one-month production period

The European Basic Safety Standards (EU-BSS) describes a set of NORM (Naturally Occurring Radioactive Material)-processing industries which produce residues known to be possibly enriched in NORs (Naturally Occurring Radionuclides). These residues can be used as a component in building materials aimed for public usage. The industrial processes, in which the residues are produced, are often complex and total monitoring can be challenging especially when the origin of the used raw materials varies. In this study the NORs present in non-ferrous fayalite slags of a secondary smelter facility, a NORM-processing industry according to the EU-BSS, were monitored daily during a one-month production period. In addition flue dust samples and feedstock samples, known to contain elevated levels of NORs, of the same period were measured. The survey involved the gamma-ray spectrometric analysis of the decay products from the 238U and 232Th decay chains, 235U and 40K using HPGe detectors. Secular equilibrium was observed for the slags, flue dust and feedstock samples in the 232Th decay chain, in contrast to the 238U decay chain. During the month in question the ratios of maximum over minimum activity concentration were 3.1 ± 0.5 for 40K, 4 ± 1 for 238U, 6 ± 1 for 226Ra, 13 ± 7 for 210Pb, 4.5 ± 0.6 for 228Ra and 4.7 ± 0.7 for 228Th for the slags. Even with the activity concentration of the feedstock material ranging up to 2.1 ± 0.3 kBq/kg for 238U, 1.6 ± 0.2 kBq for 226Ra, 22 ± 7 kBq/kg for 210Pb, 2.1 ± 0.2 kBq/kg for 228Ra and 2.0 ± 0.4 kBq/kg for 228Th, none of the slag samples exceeded the exemption/clearance levels of the EU-BSS and RP-122 part II, which can respectively provide guidance under equilibrium and in absence of equilibrium. As each NORM-processing industry has its own complexity and variability, the observed variations point out that one should approach one-time measurements or low frequency monitoring methods cautiously. Low frequency measurements should be optimised depending on the discharge of the batches. A follow up of the industrial process and its output can provide important insights to assure a limited public exposure upon application of these industrial residues.Finally a comparison is made with reported data on other metallurgical slags and the use of the slags in building materials is evaluated using the Activity Concentration Index (ACI) proposed by the EU-BSS.

Effects of image noise, respiratory motion, and motion compensation on 3D activity quantification in count-limited PET images

The aims of this study were to evaluate the effects of noise, motion blur, and motion compensation using quiescent-period gating (QPG) on the activity concentration (AC) distribution—quantified using the cumulative AC volume histogram (ACVH)—in count-limited studies such as 90Y-PET/CT. An International Electrotechnical Commission phantom filled with low 18F activity was used to simulate clinical 90Y-PET images. PET data were acquired using a GE-D690 when the phantom was static and subject to 1–4 cm periodic 1D motion. The static data were down-sampled into shorter durations to determine the effect of noise on ACVH. Motion-degraded PET data were sorted into multiple gates to assess the effect of motion and QPG on ACVH. Errors in ACVH at AC90 (minimum AC that covers 90% of the volume of interest (VOI)), AC80, and ACmean (average AC in the VOI) were characterized as a function of noise and amplitude before and after QPG. Scan-time reduction increased the apparent non-uniformity of sphere doses and the dispersion of ACVH. These effects were more pronounced in smaller spheres. Noise-related errors in ACVH at AC20 to AC70 were smaller (<15%) compared to the errors between AC80 to AC90 (>15%). The accuracy of ACmean was largely independent of the total count. Motion decreased the observed AC and skewed the ACVH toward lower values; the severity of this effect depended on motion amplitude and tumor diameter. The errors in AC20 to AC80 for the 17 mm sphere were −25% and −55% for motion amplitudes of 2 cm and 4 cm, respectively. With QPG, the errors in AC20 to AC80 of the 17 mm sphere were reduced to −15% for motion amplitudes <4 cm. For spheres with motion amplitude to diameter ratio >0.5, QPG was effective at reducing errors in ACVH despite increases in image non-uniformity due to increased noise. ACVH is believed to be more relevant than mean or maximum AC to calculate tumor control and normal tissue complication probability. However, caution needs to be exercised when using ACVH in post-therapy 90Y imaging because of its susceptibility to image degradation from both image noise and respiratory motion.

Synergistic Effect of Metal Nanoparticles on the Antimicrobial Activities of Antibiotics against Biorecycling Microbes

Biorecycling microbes, which have critical functionalities in natural cycles, are essential to sustain ecosystem of the earth. Any alterations in these cycles caused by the mutations of microbes could be a potential threat to life on earth. Antibiotics leached from pharmaceutical waste, animal food and agribusiness products are accumulating in the environment. Metal nanoparticles are also accumulating in environment because of their extensive use as biocidal agent in domestic products. Interaction of antibiotics and metal nanoparticles with eco-friendly microorganisms has a potential to alter the ecosystem of the earth. In this article, we have studied the antibacterial activities of silver and copper nanoparticles and their formulations with antibiotics, tetracycline, and kanamycin against biorecycling microbes, Bacillus subtilis and Pseudomonas fluorescens. Strong synergistic effect of metal nanoparticles on the antimicrobial activities of commercial antibiotics has been observed. Antimicrobial activity of tetracycline improves by 286%–346% and 0%–28% when being tested in the presence of 250 ppm of silver and copper nanoparticles, respectively. For kanamycin, the improvement is 154%–289% for silver and 3%–20% for copper nanoparticles. Irrespective of the antibiotics and tested organisms, synergy is more prominent for silver nanoparticles even at their minimum active concentration (100 ppm). This study demonstrates that the combination of metal nanoparticles with antibiotics could be more fatal to ecosystem than either the metal nanoparticles or the antibiotics alone.

ВИВЧЕННЯ ПРОТИВІРУСНОЇ АКТИВНОСТІ ТАБЛЕТОК АЛЬТАБОР

&lt;p&gt;&lt;strong&gt;STUDY OF ANTIVIRAL ACTIVITY OF TABLETS ALTABOR &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;S.L. Rybalko&lt;sup&gt;1&lt;/sup&gt;, &lt;/strong&gt;&lt;strong&gt;Т&lt;/strong&gt;&lt;strong&gt;.V. &lt;/strong&gt;&lt;strong&gt;К&lt;/strong&gt;&lt;strong&gt;rutskikh&lt;sup&gt;2&lt;/sup&gt;, &lt;/strong&gt;&lt;strong&gt;А&lt;/strong&gt;&lt;strong&gt;.S. Shalamay&lt;sup&gt;3&lt;/sup&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;L.V.Gromashevsky Institute of epidemiology and infectious diseases Academy of Medical Science of Ukraine, Kyiv&lt;/p&gt;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;National Pharmaceutical University, Kharkiv&lt;/p&gt;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;JSC SIC "Borshchahivka CPP", Kyiv&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt; studied antiviral activity of tablets Altabor. Determined that the drug has antiviral activity and inhibits the reproduction of Epstein-Barr virus.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words:&lt;/strong&gt; altabor, antiviral activity, influenza, Epstein-Barr virus.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Introduction.&lt;/strong&gt; Among all infectious diseases flu and SARS took first place in frequency and the number of cases in the world and account for 95%. According to WHO influenza and flu-like illness in the world is sick 5 - 30 % of the population is 500 million people. For 400 years the world's recorded over 100 epidemics of influenza pandemics and 18, which bring it with them tens of millions of lives. Today, global losses from influenza epidemics is much inferior to the scale of past pandemics due to the possibilities of modern diagnosis of the virus , the availability of antiviral and antibacterial drugs and improving health services. But the problem of treatment of disease really matter remains relevant.&lt;/p&gt;&lt;p&gt;Against the background of acute viral infections of herpes viruses can be said not, but no less threatening. Herpes was first fixed in a thousand years BC, but the problem that attracts attention, was only in the 20th century after the emergence of HIV. Today open 80 more members of the family of herpes viruses, of which 8 types pathogenic to man. One of the pathogenic types are Epstein-Barr virus, which, according to research antibodies detected in 95% of the population. At this time this virus play an important role in the formation of cancer cells in the body that causes the need for increasing attention from the medical and pharmaceutical community.&lt;/p&gt;&lt;p&gt;Create antiviral agents is one of the most difficult tasks chemotherapy infections. The reason is that viruses containing RNA and DNA components are obligate intracellular parasites. In the process of viral replication is mainly used machine biosynthesis microorganism cells, modifying its outstanding manner. In this regard, it is very difficult to find selective operating means which would killed viruses without damaging the cells are "master". However, in recent years, certain antiviral drugs that possess outstanding selective action against the infected cells and suppress the virus replicative cycle. One of these drugs is original domestic product - Altabor tablets.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods.&lt;/strong&gt; Antiviral activity of Altabor tablets studied in models in vitro. To determine influenza activity using dog kidney cell culture .The influence of tablets Altabor on virus Epstein-Barr conducted in the system Raji cells infected with the said virus.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results and discussion&lt;/strong&gt;. Altabor tablets influenza activity based on the inhibition of viral neuraminidase, an enzyme responsible for viral virion ability to penetrate the host cell and leave it after reproduction. Analyzing these data, it should be noted that tablets Altabor actively inhibit the reproduction of the influenza virus in doses from 100 mg/ml to 6.75 ug/ml 7.5-3.0 lg ID50, which indicates a strong flu drug activity. As for the study of the effect of tablets on Altabor Epstein-Barr virus, the maximum tolerated concentration was 750 mg/ml. Determined that the minimum active concentration for the drug was 0.1 mg/ml. Based on the value of the minimum and maximum tolerated concentration of active therapeutic index of tablets Altabor established at 5000, indicating a pronounced effects on reproduction of the virus.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions.&lt;/strong&gt; Result of studies on the antiviral activity of tablets Altabor found that the preparation has flu activity. Also, the drug inhibits the reproduction of Epstein-Barr virus, as evidenced therapeutic index of tablets Altabor set at 5000.&lt;/p&gt;

ВИВЧЕННЯ ПРОТИГЕРПЕТИЧНОЇ АКТИВНОСТІ ТАБЛЕТОК АЛЬТАБОР

&lt;p&gt;&lt;strong&gt;STUDY OF ANTIHERPETIC ACTIVITY OF TABLETS ALTABOR &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Т.V. Кrutskikh&lt;sup&gt;1&lt;/sup&gt;, N.V. Nesterova&lt;sup&gt;2&lt;/sup&gt;, S.D Zagorodnya&lt;sup&gt;2&lt;/sup&gt; &lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;National Pharmaceutical University, Kharkiv&lt;/p&gt;&lt;p&gt; &lt;sup&gt;2&lt;/sup&gt;Institute of Microbiology and Virology NAS of Ukraine, Kyiv, Ukraine&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt; studied antiviral activity of tablets Altabor. Determined that the drug has antiherpetic activity as therapeutic and prophylactic use of schemes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words: &lt;/strong&gt;altabor, antiherpetic activity, herpes, tablets.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Introduction.&lt;/strong&gt; Common classification of acute and recurrent herpes human diseases currently still pending. This is due to the fact that while patients with this disease are not treated to a specialist, and the doctors of different specialties - depending on the localization of acute and recurrent processes, resulting in clinical practice herpes virus disease diagnosis is "topical" in nature, etiology the disease is ignored and software etiopathogenetic treatment is performed. Today herpes infection is attracting more attention as the medical and non-medical circles of society. This is due to the fact that cold sores, known since ancient times as small and insignificant spread of disease, recently greatly expanded its importance in human pathology. Increased interest in herpes infection is also due to several other reasons and advance all that has now spread to different parts of the world, strikes to 95% of the population, and the virus is capable of causing damage almost all the organs and systems of the human body and cause various forms of infection - acute, latent and chronic recurrent. Clinically herpes occurs as diverse, complex and often severe disease with lesions of many organs and tissues, which can be considered as a general systemic disease organism.&lt;/p&gt;&lt;p&gt;Modern medicine has therapies that allow to eliminate the herpes simplex virus from the human body. Until recently, treatment was generally symptomatic herpes. Prescribed remedies that dried, to anesthetize, cooled and prevented infection lesions other microorganisms. Tried to apply and antivirals (ointment oksolin, tebrofen), but the effectiveness of most antiviral agents left much to be desired. Today treat herpes infections is complex and characterized by low efficiency. Therefore, therapies aimed at preventing the development or restoration of disorders that cause activation of the herpes virus in the body. At this time there are two main directions in the treatment of herpes, it is, first, the use of etiopathogenetic antiviral therapy, the main place in which to play acyclic nucleoside - acyclovir (Zovirax, acyclovir-acre), valaciclovir (Valtrex) and famciclovir (famvir) and Secondly, a comprehensive treatment that includes immunotherapy (specific and nonspecific) in combination with antiviral therapy.&lt;/p&gt;&lt;p&gt;Number of drugs for the treatment of herpetic lesions is limited because of new original products is appropriate and timely. One of these drugs is original domestic product - Altabor tablets that are based on Altabor substance that has antiherpetic and erferonogenie action.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods.&lt;/strong&gt; Antiherpetic activity of Altabor tablets studied in models in vitro and in vivo.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results and discussion&lt;/strong&gt;. To study antiherpetic tablets altabor activity in vitro using rabbit kidney cell culture infected with the herpes virus type 1. The results demonstrated that both in medical and in prevention of various concentrations of tablets altabor (from 100 to 6.2 mcg/ml) was observed expressed antiherpetic activity. If preventive action tablets altabor minimum active concentration was 6.2 mg/ml, for therapeutic action - 3.1 mg/ml.&lt;/p&gt;&lt;p&gt;Antiherpetic activity of altabor tablets studied in vivo against the herpes simplex virus 1 model herpes virus meningoencephalitis in white outbred mice. As the reference product used "Viroleks» KRKA (Slovenia). Based on these data concluded that the tablets have expressed altabor preventive effect at a dose of 0.5 mg/kg per os, better protect mice from herpes meningoencephalitis than drug Viroleks. Also, based on certain performance index (IE=60) can assert pronounced therapeutic activity of altabor tablets, which are much more efficient than Viroleks.&lt;/p&gt;&lt;strong&gt;Conclusions.&lt;/strong&gt; Results of the studies on the antiviral activity of tablets Altabor found that the drug shows pronounced antiherpetic activity as a therapeutic and prophylactic regimens application. If preventive action tablets altabor minimum active concentration was 6.2 mg/ml, the therapeutic action - 3.1 mg/ml. At a dose of 0.5 mg/kg per os altabor more effectively protects mice from herpes meningoencephalitis than drug Viroleks, 2 times better at prevention and 1.5 times in the application of medical schemes.

High-throughput multiple-mouse imaging with micro-PET/CT for whole-skeleton assessment

Recent studies have proven that skeleton-wide functional assessment is essential to comprehensively understand physiological aspects of the skeletal system. Therefore, in contrast to regional imaging studies utilizing a multiple-animal holder (mouse hotel), we attempted to develop and characterize a multiple-mouse imaging system with micro-PET/CT for high-throughput whole-skeleton assessment. Using items found in a laboratory, a simple mouse hotel that houses four mice linked with gas anesthesia was constructed. A mouse-simulating phantom was used to measure uniformity in a cross sectional area and flatness (Amax/Amin*100) along the axial, radial and tangential directions, where Amax and Amin are maximum and minimum activity concentration in the profile, respectively. Fourteen mice were used for single- or multiple-micro-PET/CT scans. NaF uptake was measured at eight skeletal sites (skull to tibia). Skeletal 18F activities measured with mice in the mouse hotel were within 1.6 ± 4% (mean ± standard deviation) of those measured with mice in the single-mouse holder. Single-holder scanning yields slightly better uniformity and flatness over the hotel. Compared to use of the single-mouse holder, scanning with the mouse hotel reduced study time (by 65%), decreased the number of scans (four-fold), reduced cost, required less computer storage space (40%), and maximized 18F usage. The mouse hotel allows high-throughput, quantitatively equivalent scanning compared to the single-mouse holder for micro-PET/CT imaging for whole-skeleton assessment of mice.

Expected sensitivity to antibiotics in bacterial infections

Antibiotic resistance is a common concern for infectious diseases practitioners worldwide. Given the high and increasing rate of antibiotic use, the varied mechanisms of resistance transmission between bacteria and the decreasing trend in antibiotic research, WHO cautions that we are on the verge of returning to the pre-antibiotic era. A time span of major interest to clinicians is the window for selective pressure, described as the interval below the MIC (minimum inhibitory concentration) and above the MAC (minimum active concentration). Suboptimal therapy may select resistant strains and overtreatment poses a high risk for disrupting human microbiota. Therefore, when waiting for culture results is not an option, it is extremely important to start antimicrobial therapy with the right drug in the right dose for the right duration of therapy, with de-escalation when culture results become available (Joseph et al., 2008). At times, clinical decision making prior to culture results relies on an educated guess and it is up to each physician to choose the sources of information and the necessary tools. To aid clinicians in making correct decisions for each patient, a simplified approach classifies infections into community-acquired, healthcare-associated and hospital-acquired. Valuable research in the field points towards a number of factors which may predict the risk of antibiotic resistance in a particular patient. The Carmeli score, increasingly used in clinical practice in the National Institute for Infectious Diseases “Prof.Dr. Matei Bals”, is calculated based on key facts of the patient's medical history and can be used as a readily-available instrument for assessing the expected sensitivity to antibiotics in bacterial infections. This can be achieved in a matter of minutes, by computing data on previous contact with the medical system, previous use of antibiotics and concomitant diseases. A new study (BREAST-MF) presented in this issue of the Journal is currently underway and one of its objectives is to assess the correlation between the Carmeli score and the antibiotic sensitivity profile of the human microbiota while documenting the existence or non-existence of a resident flora of the human breast. Several studies on this topic are currently underway or have already started reporting data, as is the case with SATURN (Impact of Specific Antibiotic Therapies on the Prevalence of hUman Host ResistaNt Bacteria – http://www.saturn-project.eu/) or SMART (Study for Monitoring Antimicrobial Resistance Trends – www.globalsmartsite.com/). Read through this issue of the Journal for more information on antibiotics, HIV, varicella, Mycobacterium tuberculosis and DNA vaccines.

Production of Monoclonal Antibodies Against Banana Bunchy Top Virus and Their Use in Enzyme‐Linked Immunosorbent Assay

AbstractWhen purified banana bunchy top virus (BBTV) was used to immunize Balbc mice, all 480 wells from one fusion contained hybridomas and culture fluid from 92% of them showed a positive reaction to BBTV using plate trapped antigen (PTA) ELISA (also known as indirect ELISA). After a third screening, 84 hybridoma cell lines retained their ability to produce BBTV‐specific antibodies. Fitry‐eight monoclonal cell lines with the ability to produce BBTV‐specific antibodies. were obtained when these hybridomas were cloned by limiting dilution to single cells. The antibodies produced by these monoclonal hybridomas were mostly isotype IgG2a. The titres of antibody in culture supernatant and ascitie fluid of one clone were 104 and 104, respectively, while those of another clone were as high as 104 and 104. Hybridomas produced 40 to 62 times more anti‐BBTV specific antibodies in mouse ascites than in culture. The minimum active concentration of purified immunoglobulin produced by three hybridomas ranged from 0.03 to 0.06 μg/ml, while the minimum detectable concentration of BBTV antigen was 0.26 μg/ml with PTA ELISA. Antibody trapped antigen (ATA) ELISA (also known as direct ELISA) was 16 times more sensitive than PTA ELISA in detecting BBTV. Although PTA ELISA could not detect BBTV in crude extract of diseased tissues, ATA ELISA was able to detect the virus even when the extract was diluted 1/512.

The biological effects of XTC-MIF: quantitative comparison with Xenopus bFGF

Mesoderm in Xenopus and other amphibian embryos is induced by signals from the vegetal hemisphere acting on equatorial or animal hemisphere cells. These signals are diffusible and two classes of candidate signal molecule have been identified: the fibroblast growth factor (FGF) and transforming growth factor beta (TGF-beta) types. In this paper, we compare the effects of cloned Xenopus basic FGF (XbFGF) and electophoretically homogeneous XTC-MIF (a TGF-beta-like factor obtained from a Xenopus cell line) on animal pole explants. We find that they have a similar minimum active concentration (0.1-0.2 ng ml-1) but that, nonetheless, XTC-MIF is at least 40 times more active in inducing muscle. In general, we find that the two factors cause inductions of significantly different characters in terms of tissue type, morphology, gene expression and timing. At low concentrations (0.1-1.0 ng ml-1) both factors induce the differentiation of 'mesenchyme' and 'mesothelium' as well as blood-like cells. These latter cells do not, however, react with an antibody to Xenopus globin. This raised the possibility that the identification of red blood cells in other studies on mesoderm induction might have been mistaken, but combinations of animal pole regions with ventral vegetal pole regions confirmed that genuine erythrocytes are formed. The identity of the blood-like cells formed in response to the inducing factors remains unknown. At higher concentrations XTC-MIF induces neural tissue, notochord, pronephros and substantial and often segmented muscle. By contrast, XbFGF only induces significant amounts of muscle above 24 ng ml-1 and even then this is much less than that induced by XTC-MIF. For both factors an exposure of less than 30 min is effective. Competence of animal pole cells to respond to XbFGF is completely lost by the beginning of gastrulation (stage 10) while competence to XTC-MIF is detectable until somewhat later (stage 11). Since animal pole tissue is known to be able to respond to the natural inducer at least until stage 10, and perhaps until stage 10.5, this suggests that bFGF cannot be the sole inducer of mesoderm in vivo. Taken together, these results are consistent with XTC-MIF being a dorsoanterior inducer and XbFGF a ventroposterior inducer, suggesting that body pattern is established by the interaction of two types of inducing signal. This model is discussed in view of the qualitative and quantitative differences between the factors.

An improved isolated single electroplax preparation: I. Effect of compounds acting primarily at the synapses

Acetylcholine and related structures have been tested as to their effects on the electrical activity of an improved isolated single electroplax preparation. As a measure for comparing the relative strength of the compounds, the concentration which produced 50% decrease in spike height within 20 min or less (usually from 5–15 min) was used. This concentration is referred to as the minimum active concentration. (a) Acetylcholine, decamethonium and d-tubocurarine were about 5–10 times as active as in previous preparations; no marked increase in sensitivity was observed with neostigmine and dimethylaminoethyl acetate. (b) Among the newly tested compounds succinylcholine proved to be twice as strong as acetylcholine, propionylcholine about 100 times weaker, and benzoylcholine several hundred fold weaker; the S-analogue of acetylcholine was about 3–5 times weaker. Dimethyl curare is only about half as strong as curare. (c) The decrease in spike height caused by the various quaternary compounds tested showed much better reversibility than in the previous preparation. (d) Curare in concentrations about 1000 times as high as those required to block the indirect response, abolished the propagated spike evoked by direct stimulation. In previous preparations no effect was obtained with curare outside the synaptic region even in higher concentrations than those applied in the present studies. (e) Following block of the indirect spike by curare, acetylcholine when applied in higher concentrations was able to overcome the block thys adding new evidence for the competitive action between acetylcholine and curare for the receptor. Dimethylaminoethyl acetate and the S-analogue of acetylcholine did not affect the direct spike in presence of curare in the concentrations tested. (f) Dimethylaminoethyl acetate acts much more strongly at pH 6 to 8, where it is present mostly in the cationic (protonated) form, than at pH 9, where it is present mostly in its uncharged form. The role of the Coulombic forces in the receptor protein thus appears similar to that previously observed with acetylcholinesterase. (g) The various changes of the response to acetylcholine and related structures after the removal of the adjacent membrane are a new demonstration that the effect of externally applied compounds on biological membranes depends to a great extent on the permeability barriers protecting the active membrane.