Evaluation of oral microbiota in undernourished and eutrophic children using checkerboard DNA-DNA hybridization.

The aim of this study was to evaluate the relationship among nutritional status, gingival health and the composition of oral microbiota in children of a public school from a very poor area of San Miguel de Tucuman. Forty-five children ranging in age from 6 to 14 years old, 13 males and 32 females were studied. Twenty of these children were undernourished (Lejarraga-Morasso Table) and twenty-five were eutrophic. A clinical study that included DMF and dmf indexes, Löe Silness Plaque Index and bleeding on probing was performed. For microbiological study, saliva samples without stimulation were taken; aliquots of them were immediately placed in TAE buffer pH 7.6, adding NaOH (N and keeping at -70 °C until processed by checkerboard DNA-DNA hybridization method to check the presence of 40 oral microorganism species. Positive bleeding on probing was present in more than 80% of children, without significant differences between eutrophic and undernourished groups. Same result were obtain for the other clinical indexes (p > 0.05, Two Way ANOVA). Significant differences were found for some oral microorganism species, with a higher percentage of undernourished children harboring them. That was the case of S. gordonii (p < 0.05), Capnocitophaga gingivalis and C. ochraceae (p < 0.01 and p < 0.10, respectively), F. nucleatum ss nucleatum (p < 0.05), P. nigrescens (p < 0.10), Campylobacter gracilis (p < 0,05), and T. denticola (p < 0.10, multiple logistic regression). Significant differences were also found between children groups for E. saborreum (p < 0.001), P. acnes (p < 0.10), G. morbillorum (p < 0.05) and L. buccalis (p < 0.10). Gingivitis and bleeding on probing would not be related to nutritional status in the groups of children studied. There were significant differences for the presence of some of the main periodontal pathogen species between eutrophic and undernourished children. It would be important to study the meaning of significant differences found for the other microorganisms more deeply.

On the geometry of surface stress.

We present a fully general derivation of the Laplace-Young formula and discuss the interplay between the intrinsic surface geometry and the extrinsic one ensuing from the immersion of the surface in the ordinary Euclidean three-dimensional space. We prove that the (reversible) work done in a general surface deformation can be expressed in terms of the surface stress tensor and the variation of the intrinsic surface metric.

First Report of Southern Blight Caused by Sclerotium rolfsii on Common Bean (Phaseolus vulgaris) in Italy.

Common bean (Phaseolus vulgaris L.) is grown worldwide for consumption of dry or green beans. During late spring of 2012, yellowing and wilting symptoms were observed in a commercial bean field cv. Lingua di fuoco in Cagliari Province (Sardinia, southern Italy) on 30% of plants 4 to 5 months after sowing. The first symptoms developed in May, when temperatures reached 18 to 30°C. Affected plants showed crown rot, necrosis of the cortex, and foliar chlorosis. As disease progressed, plants collapsed. In the presence of abundant moisture, white mycelium developed on the senescent tissue along with light to dark brown sclerotia (3.0 to 4.8 mm in diameter). Symptomatic tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 25 mg streptomycin sulfate/liter. The fungus that was isolated consistently from symptomatic plants onto PDA at 23°C grew rapidly in culture with silky-white, sterile mycelium, formed light to dark brown sclerotia (each 1.8 to 3.2 mm in diameter) after 7 days, and readily produced aerial hyphae. These morphological features are typical of Sclerotium rolfsii (2). The internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) was amplified for one isolate using ITS1/ITS4 primers (4), and sequenced (GenBank Accession No. KF002510). BLASTn analysis (1) of the 656-bp segment showed 87% homology with the ITS sequence of an S. rolfsii isolate (JF819727). Pathogenicity of one isolate was confirmed by inoculating healthy P. vulgaris plants cv. Lingua di fuoco grown in 2-liter pots in a steamed potting mix containing 50% Tecno2 (70% white peat and 30% clay) and 50% Tiesse 3 (60% white peat, 20% clay, and 20% perlite) (Turco Silvestro terricci, Bastia d'Albenga, SV, Italy). Inoculum consisting of mycelium and sclerotia of the pathogen produced from 10-day-old cultures on PDA was mixed in the soil at 0.5 g/liter substrate. Four 7-day-old plants per pot, with three replicate pots, were used for inoculation. The same number of control plants grown in the same substrate were inoculated with non-colonized PDA as a negative control treatment. The pathogenicity test was repeated. Plants were kept in a growth chamber at 30°C and 85% RH. Inoculated plants developed symptoms of leaf yellowing within 10 days, followed by crown rot, appearance of white mycelium and sclerotia, and eventual wilting. Control plants remained asymptomatic. Isolations from inoculated plants demonstrated the absence of latent infections by the fungus S. rolfsii, but the fungus was not reisolated from non-inoculated control plants. To our knowledge, this is the first report of S. rolfsii infecting P. vulgaris in Italy. Southern blight has been reported on common bean in sub-tropical and tropical areas of the world (3), where it can cause severe crop losses. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) J. E. M. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria No. 410, 1974. (3) H. F. Schwartz et al. Page 20 in: Compendium of Bean Diseases. American Phytopathological Society Press, St. Paul, MN, 2005. (4) T. J. White et al. PCR Protocols. Page 315 in: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

Animal performance and meat quality characteristics from feedlot-finished steers fed increasing levels of wet distillers grain.

One hundred forty-four steers were group-housed in 24 pens that were randomly assigned to one of four dietary treatments defined by the proportion of wet distiller grain plus solubles (WDGS; 0, 15, 30, or 45%) and fed for 84 d pre-slaughter. Animal performance was evaluated using the pen as the experimental unit. Whereas for carcass and meat quality characteristics, meat oxidative stability, and the consumer sensory quality of longissimus thoracis muscle one animal from each pen was randomly selected and used as the experimental unit. No differences (P > 0.05) were observed for subcutaneous fat thickness, rib eye area, marbling score or pH, color parameters, proximate composition, sarcomere length, Warner Bratzler shear force, and cooking loss. Feeding WDGS linearly increased total PUFA (P = 0.05), C18:2 n-6 (P = 0.004) proportions, and n-6/n-3 ratio (P < 0.01) but reduced C16:1 to C18:0 ratio (P < 0.01). Lipid oxidation was greater in beef from steers fed 30% and 45% WDGS (P = 0.05). Dietary WDGS linearly improved (P < 0.05) flavor and overall linking score in the consumer sensory panel.

Life Cycle Assessment of a system for the extraction and transformation of Waste Water Treatment Sludge (WWTS)-derived lipids into biodiesel.

In recent years, the demand for biofuels has been growing exponentially, as has the interest in biodiesel produced from organic matrices. Particularly interesting, due to its economic and environmental advantages, is the use of the lipids present in sewage sludge as a raw material for the synthesis of biodiesel. The possible processes of this biodiesel synthesis, starting from lipid matter, are represented by the conventional process with sulfuric acid, by the process with aluminium chloride hexahydrate and by processes that use solid catalysts such as those consisting of mixed metal oxides, functionalized halloysites, mesoporous perovskite and functionalized silicas. In literature there are numerous Life Cycle Assessment (LCA) studies concerning biodiesel production systems, but not many studies consider processes that start from sewage sludge and that use solid catalysts. In addition, no LCA studies were reported on solid acid catalysts nor on those based on mixed metal oxides which present some precious advantages, over the homogeneous analogous ones, such as higher recyclability, prevention of foams and corrosion phenomena, and an easier separation and purification of biodiesel product. This research work reports the results of a comparative LCA study applied to a system that uses a solvent free pilot plant for the extraction and transformation of lipids from sewage sludge via seven different scenarios that differ in the type of catalyst used. The biodiesel synthesis scenario using aluminium chloride hexahydrate as catalyst has the best environmental profile. Biodiesel synthesis scenarios using solid catalysts are worse due to higher methanol consumption which requires higher electricity consumption. The worst scenario is the one using functionalized halloysites. Further future developments of the research require the passage from the pilot scale to the industrial scale in order to obtain environmental results to be used for a more reliable comparison with the literature data.

Ranunculus latent virus: a strain of artichoke latent virus or a new macluravirus infecting artichoke?

An elongated virus was isolated from artichoke crops in Liguria, and a 700-bp fragment was amplified by RT-PCR using oligonucleotides to detect members of the family Potyviridae. Comparison of fragment sequences showed 98% identity at the nucleotide level with the ranunculus isolate of the macluravirus Ranunculus latent virus (RaLV). RaLV was then detected by DAS-ELISA in symptomatic and asymptomatic artichoke plants from Liguria, Sardinia and Latium. The sequence of a 5.5-kb region was assembled from a cDNA library, and a 500-bp NIa fragment showed 80% identity to Artichoke latent virus.

Objective assessment of mandibular motor control using a 'reach-and-hold' task.

Mandibular motor function is well known to be impaired in the presence of temporomandibular disorders. However, while a vast literature is available concerning accuracy of motor control in limbs, quantitative and objective assessment of mandibular motor control has been seldom performed, also because of the lack of adequate investigative tools. Aim of this work is to present a technique for reliable evaluation of the motor performance of the mandible based on a kinesiography-monitored reach-and-hold task. Nineteen healthy subjects were engaged in a task in which they had to drive a cursor on a screen by corresponding movements of the mandible in the frontal plane and reach 30 random targets sequentially displayed on the screen. The whole task was repeated three times per session in two different days. The individual performance was assessed by different indices evaluating precision and steadiness of target matching. The performance progressively improved in the three trials of the first session, further improved and stabilised in the second session, with an average positioning error of 0·59 ± 038 mm and was slightly correlated with the horizontal dimension of the mandible border movement (r = 0·55). Intraclass correlation coefficient ranged between 0·76 and 0·94 for the different indices indicating good repeatability. The kinesiographic technique allowed for objective and reliable assessment of the voluntary control of the mandible position. Its potential applications include support to the characterisation of temporomandibular disorders and to motor training and progress monitoring in rehabilitation treatments.

Low back pain among Italian runners: A cross-sectional survey.

BACKGROUND: Low Back Pain (LBP) is commonly reported as a very frequent disorder in sports, but its prevalence in runners remains unclear. OBJECTIVES: To determine the prevalence of LBP in a wide sample of Italian runners. DESIGN: A cross-sectional online survey. SETTING: A national survey, according to the CHERRIES and STROBE guidelines, was performed in 2019. PARTICIPANTS: 2539 Italian runners. METHODS: A sample of Italian runners registered with national running associations was recruited. The survey was conducted using an online survey development platform. The questionnaire was self-reported and included 38 questions. MAIN OUTCOME MEASURES: Descriptive statistics and frequencies were used to analyze results. Relationships between demographics, daily habits and running characteristics and the responses given was calculated with Cramer's V. Only correlation values higher >0.60 were deemed of interest. RESULTS: 2539 questionnaires (63.5%) were valid for analysis. In total, 22.6% of runners reported having experienced LBP in the past year. Most participants (77.0%) reporting episodes of LBP believed it was not caused by running. No significant correlations (Cramer's V < 0.60) were found between LBP and demographics, training characteristics or lifestyle habits. CONCLUSION: The prevalence of LBP among Italian runners was 22,57%. LBP was not associated with training, equipment or lifestyle.

Patient-reported outcomes following treatment with the human GLP-1 analogue liraglutide or glimepiride in monotherapy: results from a randomized controlled trial in patients with type 2 diabetes.

AIM: As weight gain and hypoglycaemia associated with glimepiride therapy can negatively impact weight perceptions, psychological well-being and overall quality of life in type 2 diabetes, we investigated whether liraglutide treatment could improve these factors. METHODS: Seven hundred and thirty-two patients with type 2 diabetes completed a 77-item questionnaire during a randomized, 52-week, double-blind study with liraglutide 1.2 mg (n = 245) or 1.8 mg (n = 242) compared with glimepiride 8 mg (n = 245). RESULTS: Mean (SE) decreases in glycated haemoglobin levels were greater with liraglutide 1.2 mg [-0.84 (0.08)%] and 1.8 mg [-1.14 (0.08)%] than glimepiride [-0.51 (0.08)%; p = 0.0014 and p < 0.0001, respectively]. Patients gained weight on glimepiride [mean (SE), 1.12 (0.27) kg] but lost weight on liraglutide [1.2 mg: -2.05 (0.28) kg; 1.8 mg: -2.45 (0.28) kg; both p < 0.0001]. Patient weight assessment was more favourable with liraglutide 1.8 mg [mean (SE) score: 40.0 (2.0)] than glimepiride [48.7 (2.0); p = 0.002], and liraglutide 1.8 mg patients were 52% less likely to feel overweight [odds ratio (OR) 0.48; 95% confidence interval (CI): 0.331-0.696]. Mean (SE) weight concerns were less with liraglutide [1.2 mg: 30.0 (1.2); 1.8 mg: 32.8 (1.2)] than glimepiride [38.8 (1.2); p < 0.0001 and p < 0.001, respectively], with liraglutide groups 45% less likely to report weight concern (OR 0.55, 95% CI: 0.41-0.73). Mean (SE) mental and emotional health and general perceived health improved more with liraglutide 1.8 mg [476.1 (2.8) and 444.2 (3.2), respectively] than glimepiride [466.3 (2.8) and 434.5 (3.2), respectively; p = 0.012 and p = 0.033, respectively]. CONCLUSIONS: Improved glycaemic control and decreased weight with liraglutide 1.8 mg vs. glimepiride can improve psychological and emotional well-being and health perceptions by reducing anxiety and worry associated with weight gain.

The stress tensor in thermodynamics and statistical mechanics.

We prove that the stress tensor, tau(ab), of a molecular system with arbitrary, short-range interactions can be point-wisely expressed as the functional derivative of the partition function with respect to the local deformation tensor. In this approach, the set of components of tau(ab) has a simple interpretation as the set of Lagrangian multipliers which one needs to introduce to enforce the conditions relating point particle displacements to the body local deformation tensor. The question of the possible nonuniqueness of the formula for tau(ab) is discussed.

Real-time monitoring of the Bragg-peak position in ion therapy by means of single photon detection.

For real-time monitoring of the longitudinal position of the Bragg-peak during an ion therapy treatment, a novel non-invasive technique has been recently proposed that exploits the detection of prompt gamma-rays issued from nuclear fragmentation. Two series of experiments have been performed at the GANIL and GSI facilities with 95 and 305 MeV/u (12)C(6+) ion beams stopped in PMMA and water phantoms. In both experiments, a clear correlation was obtained between the carbon ion range and the prompt photon profile. Additionally, an extensive study has been performed to investigate whether a prompt neutron component may be correlated with the carbon ion range. No such correlation was found. The present paper demonstrates that a collimated set-up can be used to detect single photons by means of time-of-flight measurements, at those high energies typical for ion therapy. Moreover, the applicability of the technique both at cyclotron and at synchrotron facilities is shown. It is concluded that the detected photon count rates provide sufficiently high statistics to allow real-time control of the longitudinal position of the Bragg-peak under clinical conditions.

Weight Regain and Diabetes Evolution After Sleeve Gastrectomy: a Cohort Study with over 5 Years of Follow-Up.

BACKGROUND: A number of meta-analyses have demonstrated the effectiveness of bariatric surgery in improving morbid obesity and its associated co-morbidities. The aim of the study was to evaluate at long term a cohort of obese patients with type 2 diabetes (T2DM) submitted to laparoscopic sleeve gastrectomy (LSG) analyzing the incidence of weight regain (WR) and the impact of the WR on T2DM evolution. METHODS: Seventy-eight morbid obese patients (54 females) with T2DM, aged 49.6 ± 8.7 years, weight 121.1 ± 24.4 kg, BMI 44.1 ± 7.2 kg/m2, underwent primary LSG. The trend over time of T2DM after LSG was analyzed in the different groups, subdivided on the basis of the absence or presence of WR and of its different degrees: no regain (NR), mild regain (MR), and severe regain (SR) groups. RESULTS: In the NR group, 54% show complete remission, 46% persistence, and no case of diabetes relapse; in the MR group, 59% show complete remission, 36% persistence, and 5% relapse; in the SR group, 61% show complete remission, 22% persistence, and 17% relapse. A statistically significant difference concerns the preoperative values of fasting glucose, glycosylated hemoglobin, and duration of diabetes, major in the group with diabetes relapse (respectively, p = 0.002, p = 0.001, and p < 0.0001). CONCLUSIONS: The results of this study showed no significant difference regarding the trend of diabetes remission comparing the "no regain," "mild regain," and "severe regain" groups and confirmed the importance of the duration of the illness and an early intervention towards surgical therapy.

Seasonal trends of whitefly populations in a Mediterranean tomato growing area.

The whiteflies Bemisia tabaci and Trialeurodes vaporariorum and their associated viruses constitute a major threat to tomato crops in the Mediterranean region. Continuous host availability and mild climate are thought to be among the factors contributing to the outbreaks of whitefly-related problems in this area. We carried out a year-long survey to investigate the relative contribution of different plants, agricultural and not, and indoor/outdoor crops as hosts of the two whiteflies and the tomato yellow leaf curl disease (TYLCD) in a multi-crop system typical of tomato growing areas in southern Sardinia (S. Margherita di Pula, Cagliari, Italy). For this purpose, during 2005 we monitored whitefly population trends in different plots of a horticulture farm, evaluated seasonal changes in the infestation density of the two pests on the most represented host species and assessed the incidence of TYLCD on tomato crops and susceptible weeds. Whitefly catches on yellow sticky traps were found to be higher inside et along the external perimeter of greenhouses compared to open field crops or uncultivated areas, thus suggesting significant adult movement between indoor and outdoor patches. In most plots flight activity increased between late spring and late summer, peaking in July. The number of immatures of the two whitefly species showed similar dynamics, but while T. vaporariorum reached the highest densities in greenhouse tomato crops in June, peak levels of 8. tabaci were recorded between July and August in outdoor horticultural crops and weeds. The occurrence of TYLCD was detected all year round on weed hosts, but the highest number of infected plants was observed in June on long cycle tomato crops. The present survey has demonstrated the contribution of non-agricultural plants the maintenance of tomato yellow leaf curl disease in the study site. However, tomato crops established in summer as major reservoirs of TYLCD-associated viruses and presumably played a key role in the spread of the disease to autumn tomato crops. The implementation of a crop-free period between successive susceptible crops, or at least the avoiding of whitefly movement through greenhouse openings and the complete destruction of plants after final harvest, would probably reduce the severity of TYLCD epidemics in this area.

An epidemiological survey of TYLCD in southern Sardinia (Italy).

Tomato yellow leaf curl Sardinia virus (TYLCSV) and Tomato yellow leaf curl virus (TYLCV) are among the most virulent pathogens of greenhouse tomatoes in Sardinia (Italy). To investigate the relationship between seasonal population trends of the vector Bemisia tabaci and the dynamics of TYLCD spread to susceptible crops, between May and October 2007 we carried out a survey in a tomato growing area located in the south of the island. On three farms specialized in the production of fresh market tomatoes we monitored, outside commercial greenhouses, the following parameters related to TYLCD epidemiology: mean weekly catches of the whiteflies B. tabaci and Trialeurodes voporariorum on yellow sticky traps, ratio between the two whitefly species and proportion of B. tabaci adults carrying TYLCSV/TYLCV in adult samples collected on hosts not susceptible to the disease, proportion of tomato plants infected by TYLCSV/TYLCV after a two-week exposure to open field conditions. Generally speaking, the flight activity of whiteflies increased during spring, reached a peak in May or June and gradually declined in summer. At the beginning of the survey, T. vaporariorum was found to be the prevalent species, but after a shift in composition of whitefly populations during July, B. tabaci became predominant. While the percentage of vector adults carrying the viral agents of the disease was relatively high up to July, with maximum values ranging between 14 and 25%, during the following months it decreased to less than 5%. The incidence of TYLCD in the plants exposed outside the greenhouses showed a similar trend in the sites surveyed, with two peaks roughly coinciding with the beginning and end of summer. Therefore, two distinct phases of TYLCD spread were observed: from spring to midsummer when the disease was transmitted by low 8. tabaci populations with relatively high proportions of virus carriers; from midsummer to autumn, when the disease was spread by larger vector populations with low percentages of individuals carrying the viruses. Further studies are necessary to gain a better understanding of the interactions among B. tabaci biotypes, TYLCSV/TYLCV and their hosts.

Creatine supplementation exacerbates ethanol-induced hepatic damage in mice.

OBJECTIVE: The aim of this study was to investigate the effects of creatine supplementation on early stages of ethanol-induced hepatic damage. METHODS: Male Swiss mice were divided into three groups (n = 12/group): control (C), ethanol (E), and ethanol supplemented with creatine (EC). The control group received a diet containing 15.8% of total calories from proteins, 46.3% from carbohydrates, and 37.9% from lipids. The ethanol and ethanol and creatine groups received diets containing 15.8% of total calories from proteins, 16.2% from carbohydrates, and 34.5% from lipids; the remaining calories were obtained from the addition of 5% of 95% ethanol. Creatine (1%; weight/vol) was added to the diet of EC mice. After 14 and 28 d, six animals from each group were sacrificed, generating subdivisions in each group: C14 and C28, E14 and E28, EC14 and EC28. After sacrifice, the liver was removed, weighed, and prepared for histologic, biochemical, and molecular analysis, and blood was collected. RESULTS: Ethanol intake induced mild cell degeneration, liver damage, oxidative lesions, and inflammation. Surprisingly, ethanol intake combined with creatine exacerbated cell degeneration and fat accumulation, hepatic expression of genes related to ethanol metabolism, oxidative stress and inflammation, and promoted oxidative stress and elevated plasma alanine aminotransferase (P < 0.05). CONCLUSION: Creatine supplementation associated with ethanol is able to interfere in the alcohol metabolism and oxidative stress and to exacerbate ethanol-induced hepatic damage. These new findings are opposite to those observed in several studies where protective effects of creatine in a wide variety of injury models, including non-alcoholic fatty liver disease, were described.

Alterations in jaw clenching force control in people with myogenic temporomandibular disorders.

Isometric bite force control, via measures of force accuracy, force steadiness and force proprioception, was assessed in patients with myogenic temporomandibular disorders (TMDs) compared to healthy controls. Twelve people with myogenic TMDs and twelve age- and gender-matched asymptomatic controls performed maximal voluntary contractions (MVC) of unilateral jaw clenching followed by submaximal isometric contractions, with and without visual feedback of force, at 10, 30 50% and 70% MVC. Force performance was assessed with indices of accuracy (mean distance, MD) and precision (standard deviation, SD) and reported as a percentage of the MVC. A mixed-effect model was used to evaluate differences in MVC, MD and SD. The MVC was lower in the TMD group when clenching either ipsilateral or contralateral to the side of greatest pain (p < 0.05). No difference in MD was observed between groups. The SD depended on the interaction between group and painful side (p = 0.04) with the TMD group displaying higher SD when executing the task with the most painful side when compared to the ipsilateral or contralateral sides of the control group. The reduced maximal bite force and force steadiness observed in people with myogenic pain may interfere with masticatory function and should be considered when planning therapeutic interventions for TMDs.

Antibiotics and antifungals in neonatal intensive care units: a review.

The incidence of infections is higher in the neonatal period than at any time of life. The basic treatment of infants with infection has not changed substantially over the last years. Antibiotics (with or without supportive care) are one of the most valuable resources in managing sick newborn babies. Early-onset (ascending or transplacental) or late-onset (hospital acquired) infections present different chronology, epidemiology, physiology and outcome. Some classes of antibiotics are frequently used in the neonatal period: penicillins, cephalosporins, aminoglycosides, glycopeptides, monobactams, carbapenems. Other classes of antibiotics (chloramphenicol, cotrimoxazole, macrolides, clindamycin, rifampicin and metronidazole) are rarely used. Due to emergence of resistant bacterial strains in Neonatal Intensive Care Units (NICU), other classes of antibiotics such as quinolones and linezolid will probably increase their therapeutic role in the future. Although new formulations have been developed for treatment of fungal infections in infants, amphotericin B remains first-line treatment for systemic Candida infection. Prophylactic antibiotic therapy is almost always undesirable. Challenges from pathogens and antibiotic resistance in the NICU may warrant modification of traditional antibiotic regimens. Knowledge of local flora and practical application of different antibiotic characteristics are key to an effective and safe utilization of antibiotics and antifungals in critical newborns admitted to the NICU, and especially in very low birth weight infants.

Experimental assessment of proton dose calculation accuracy in inhomogeneous media.

PURPOSE: Proton therapy with Pencil Beam Scanning (PBS) has the potential to improve radiotherapy treatments. Unfortunately, its promises are jeopardized by the sensitivity of the dose distributions to uncertainties, including dose calculation accuracy in inhomogeneous media. Monte Carlo dose engines (MC) are expected to handle heterogeneities better than analytical algorithms like the pencil-beam convolution algorithm (PBA). In this study, an experimental phantom has been devised to maximize the effect of heterogeneities and to quantify the capability of several dose engines (MC and PBA) to handle these. METHODS: An inhomogeneous phantom made of water surrounding a long insert of bone tissue substitute (1×10×10 cm3) was irradiated with a mono-energetic PBS field (10×10 cm2). A 2D ion chamber array (MatriXX, IBA Dosimetry GmbH) lied right behind the bone. The beam energy was such that the expected range of the protons exceeded the detector position in water and did not attain it in bone. The measurement was compared to the following engines: Geant4.9.5, PENH, MCsquare, as well as the MC and PBA algorithms of RayStation (RaySearch Laboratories AB). RESULTS: For a γ-index criteria of 2%/2mm, the passing rates are 93.8% for Geant4.9.5, 97.4% for PENH, 93.4% for MCsquare, 95.9% for RayStation MC, and 44.7% for PBA. The differences in γ-index passing rates between MC and RayStation PBA calculations can exceed 50%. CONCLUSION: The performance of dose calculation algorithms in highly inhomogeneous media was evaluated in a dedicated experiment. MC dose engines performed overall satisfactorily while large deviations were observed with PBA as expected.

Variation in the protein coding region of the human p53 gene.

This report describes a restriction fragment length polymorphism for the enzyme BglII caused by a conserved C to T change at residue 21 of the human p53 gene. This RFLP could potentially be misinterpreted as a rearrangement or a point mutation if paired constitutional tissue is not simultaneously analyzed.