Evaluation of a Novel Field-placement Algorithm for Locoregional Breast Cancer Radiotherapy Including the Internal Mammary Chain.

AIMS: Irradiation of the internal mammary chain (IMC) is increasing following recently published data, but the need for formal delineation of lymph node volumes is slowing implementation in some healthcare settings. A field-placement algorithm for irradiating locoregional lymph nodes including the IMC could reduce the resource impact of introducing irradiation of the IMC. This study describes the development and evaluation of such an algorithm. MATERIALS AND METHODS: An algorithm was developed in which six points representing lymph node clinical target volume borders (based on European Society for Radiotherapy and Oncology consensus nodal contouring guidelines) were placed on computed tomography-defined anatomical landmarks and used to place tangential and nodal fields. Single-centre testing in 20 cases assessed the success of the algorithm in covering planning target volumes (PTVs) and adequately sparing organs at risk. Plans derived using the points algorithm were also compared with plans generated following formal delineation of nodal PTVs, using the Wilcoxon signed rank test. Timing data for point placement were collected. Multicentre testing using the same methods was then carried out to establish whether the technique was transferable to other centres. RESULTS: Single-centre testing showed that 95% of cases met the nodal PTV coverage dose constraints (binomial probability confidence interval 75.1-99.9%) with no statistically significant reduction in mean heart dose or ipsilateral lung V17Gy associated with formal nodal delineation. In multicentre testing, 69% of cases met nodal PTV dose constraints and there was a statistically significant difference in IMC PTV coverage using the points algorithm when compared with formally delineated nodal volumes (P < 0.01). However, there was no difference in axillary level 1-4 PTV coverage (P = 0.11) with all cases meeting target volume constraints. CONCLUSIONS: The optimal strategy for breast and locoregional lymph node radiotherapy is target volume delineation. However, use of this novel points-based field-placement algorithm results in dosimetrically acceptable plans without the need for formal lymph node contouring in a single-centre setting and for the breast and level 1-4 axilla in a multicentre setting. Further quality assurance measures are needed to enable implementation of the algorithm for irradiation of the IMC in a multicentre setting.

The UK HeartSpare Study (Stage II): Multicentre Evaluation of a Voluntary Breath-hold Technique in Patients Receiving Breast Radiotherapy.

AIMS: To evaluate the feasibility and heart-sparing ability of the voluntary breath-hold (VBH) technique in a multicentre setting. MATERIALS AND METHODS: Patients were recruited from 10 UK centres. Following surgery for early left breast cancer, patients with any heart inside the 50% isodose from a standard free-breathing tangential field treatment plan underwent a second planning computed tomography (CT) scan using the VBH technique. A separate treatment plan was prepared on the VBH CT scan and used for treatment. The mean heart, left anterior descending coronary artery (LAD) and lung doses were calculated. Daily electronic portal imaging (EPI) was carried out and scanning/treatment times were recorded. The primary end point was the percentage of patients achieving a reduction in mean heart dose with VBH. Population systematic (Σ) and random errors (σ) were estimated. Within-patient comparisons between techniques used Wilcoxon signed-rank tests. RESULTS: In total, 101 patients were recruited during 2014. Primary end point data were available for 93 patients, 88 (95%) of whom achieved a reduction in mean heart dose with VBH. Mean cardiac doses (Gy) for free-breathing and VBH techniques, respectively, were: heart 1.8 and 1.1, LAD 12.1 and 5.4, maximum LAD 35.4 and 24.1 (all P<0.001). Population EPI-based displacement data showed Σ =+1.3-1.9 mm and σ=1.4-1.8 mm. Median CT and treatment session times were 21 and 22 min, respectively. CONCLUSIONS: The VBH technique is confirmed as effective in sparing heart tissue and is feasible in a multicentre setting.

Multileaf collimation cardiac shielding in breast radiotherapy: Cardiac doses are reduced, but at what cost?

AIMS: To measure cardiac tissue doses in left-sided breast cancer patients receiving supine tangential field radiotherapy with multileaf collimation (MLC) cardiac shielding of the heart and to assess the effect on target volume coverage. MATERIALS AND METHODS: Sixty-seven consecutive patients who underwent adjuvant radiotherapy to the left breast (n = 48) or chest wall (n = 19) in 2009/2010 were analysed. The heart, left anterior descending coronary artery (LAD), whole breast and partial breast clinical target volumes (WBCTV and PBCTV) were outlined retrospectively (the latter only in patients who had undergone breast-conserving surgery [BCS]). The mean heart and LAD NTDmean and maximum LAD doses (LADmax) were calculated for all patients (NTDmean is a biologically weighted mean dose normalised to 2 Gy fractions using a standard linear quadratic model). Coverage of WBCTV and PBCTV by the 95% isodose was assessed (BCS patients only). RESULTS: The mean heart NTDmean (standard deviation) was 0.8 (0.3) Gy, the mean LAD NTDmean 6.7 (4.3) Gy and the mean LADmax 40.3 (10.1) Gy. Coverage of the WBCTV by 95% isodose was <90% in one in three patients and PBCTV coverage <95% (range 78-94%) in one in 10 BCS patients. CONCLUSION: The use of MLC cardiac shielding reduces doses to cardiac tissues at the expense of target tissue coverage. Formal target volume delineation in combination with an assessment of the likelihood of local relapse is recommended in order to aid decisions regarding field and MLC placement.

Medulloblastoma.

Medulloblastomas are primary malignant embryonal tumours of the central nervous system. They are the most common childhood central nervous system tumour, but are rare in the adult population. They arise infratentorially in the cerebellum or fourth ventricle and hence the most common presenting symptoms are those associated with raised intracranial pressure. Several histological subtypes have been described, although the classical and desmoplastic subtypes account for the majority. Recent advances in molecular biology and cytogenetics have led to an improved understanding of the genetic abnormalities and alterations in cell signalling pathways associated with medulloblastomas, including how these relate to patient outcome. The Modified Chang Staging System is still in use, but a number of other factors, including age, completeness of resection, histological subtype and genetic markers now contribute to treatment decisions and prognostication. Patients are currently classified as being either standard or high risk in order to stratify treatment. There has been an improvement in survival of all groups over the past 20 years. A multimodality approach is the cornerstone of treatment and recent trials have concentrated on ascertaining the most efficacious treatment combinations and timings for each patient group. Advances in surgical techniques have allowed a greater attainment of the two primary surgical goals: restoring normal cerebrospinal fluid (CSF) flow and maximal tumour resection. Radiotherapy to the craniospinal axis with a boost to the posterior fossa has been standard practice, but improvement in radiotherapy techniques and quality control has enabled optimisation of the trade-off between tumour control and normal tissue late toxicities. Combination chemotherapy is usually given adjuvantly, although it may be used to delay or avoid the use of radiotherapy in infants. In the future, the treatment of medulloblastoma will probably become increasingly individualised, based on patient-specific genetic features. Attention will be focussed not only on improving survival, but also on maintaining quality of life.

Thermal inactivation of Pediococcus sp. in simulated apple cider during high-temperature short-time pasteurization.

Prompted by concerns regarding outbreaks of food-borne illness which have occurred due to the consumption of commercial, nonpasteurized fruit juices contaminated with Escherichia coli O157:H7, the US Food and Drug Administration and Canadian Food Inspection Agency are considering several new safety standards to apply to fresh juices, including mandatory pasteurization of all apple cider. In support of these initiatives, a study was conducted to evaluate the pasteurization of simulated cider using a heat-resistant nonpathogenic test bacterium, Pediococcus sp. NRRL B-2354. Thermal inactivation of the Pediococcus sp. was determined using a pilot scale high-temperature short-time (HTST) pasteurizer with a plate heat exchanger. The cumulative lethal effect, or pasteurization effect (PE), was obtained by converting times at different temperatures in the various sections of the pasteurizer to the equivalent time at the reference temperature (72 degrees C). PE was then related by a simple linear function to the log(10) of the percentage of viable counts with a power transformation of the PE values to improve linear fit. r(2) values for the four Pediococcus sp. trials varied from 0.921 to 0.981. Intertrial variation was incorporated into the model using @RISK simulation software. Output from simulations confirmed that treatment at 71 degrees C for 16 s can ensure a 5-log reduction of Pediococcus sp.

A major effect QTL determined by multiple genes in epileptic EL mice.

The EL mouse strain provides a polygenic model for epilepsy. Previous mapping experiments between EL and nonepileptic ABP mice identified, and a congenic strain confirmed, a quantitative trait locus (QTL), El2, which lowered the threshold to seizures induced by gentle rhythmic tossing. To narrow the map interval further we used a nested strategy to analyze a series of recombinants derived from the congenic strain. The recombinant strains revealed a complex pattern of inheritance, with at least two independent regions of Chromosome 2 necessary for rhythmic tossing seizures and additional regions associated with unusual gender effects. Similar results obtained using a completely independent paradigm, pentylenetetrazole-induced tonic-clonic seizures, exclude the possibility that the genetic complexity was a unique property of the testing assay. Thus, although conventional QTL mapping efforts detected and appeared to confirm a trait locus with effects large enough for fine-structure mapping, subsequent dissection revealed multiple loci. Although at least one of these loci was mapped to a 1-cM interval, its individual effect is small, perhaps approaching the practical limits for further study. Our results in the EL mouse may be prophetic for similar assaults on other polygenic, composite neurological behaviors which vary among inbred strains, begging the consideration of alternative strategies toward gene identification in these models.

Nisin reduces the thermal resistance of Listeria monocytogenes Scott A in liquid whole egg.

D-values (decimal reduction times) and z-values (increase in temperature required for a 1-log change in D-value) for Listeria monocytogenes Scott A were determined in liquid whole egg with nisin (0 or 10 microg ml(-1)) and NaCl (0 or 10%) by a submerged glass ampoule procedure. Samples were plated onto nonselective agar at appropriate intervals, and D-values were determined using a modified biphasic logistic equation. Addition of NaCl increased D-values at all temperatures tested. The addition of nisin to unsalted liquid whole egg resulted in a rapid 4-log reduction in viable counts within the first hour. Nisin significantly (P < or = 0.05) decreased D-values at lower (< 58 degrees C) temperatures in both unsalted and salted liquid whole egg but had little effect on the D-values at current minimum U.S. and Canadian pasteurization temperatures (60 degrees C without NaCl; 63 degrees C with NaCl). However, when nisin was added 2 h prior to heat treatment, D-values were significantly (P < or = 0.05) reduced at these temperatures. Inhibitory levels of nisin were detected in the liquid whole egg postpasteurization. Nisin could have a favorable impact on the control of L. monocytogenes in pasteurized liquid egg products.

The mouse stargazer gene encodes a neuronal Ca2+-channel gamma subunit.

Stargazer mice have spike-wave seizures characteristic of absence epilepsy, with accompanying defects in the cerebellum and inner ear. We describe here a novel gene, Cacng2, whose expression is disrupted in two stargazer alleles. It encodes a 36-kD protein (stargazin) with structural similarity to the gamma subunit of skeletal muscle voltage-gated calcium (Ca2+) channels. Stargazin is brain-specific and, like other neuronal Ca2+-channel subunits, is enriched in synaptic plasma membranes. In vitro, stargazin increases steady-state inactivation of alpha1 class A Ca2+ channels. The anticipated effect in stargazer mutants, inappropriate Ca2+ entry, may contribute to their more pronounced seizure phenotype compared with other mouse absence models with Ca2+-channel defects. The discovery that the stargazer gene encodes a gamma subunit completes the identification of the major subunit types for neuronal Ca2+ channels, namely alpha1, alpha2delta, beta and gamma, providing a new opportunity to understand how these channels function in the mammalian brain and how they may be targeted in the treatment of neuroexcitability disorders.

The hypocretins: hypothalamus-specific peptides with neuroexcitatory activity.

We describe a hypothalamus-specific mRNA that encodes preprohypocretin, the putative precursor of a pair of peptides that share substantial amino acid identities with the gut hormone secretin. The hypocretin (Hcrt) protein products are restricted to neuronal cell bodies of the dorsal and lateral hypothalamic areas. The fibers of these neurons are widespread throughout the posterior hypothalamus and project to multiple targets in other areas, including brainstem and thalamus. Hcrt immunoreactivity is associated with large granular vesicles at synapses. One of the Hcrt peptides was excitatory when applied to cultured, synaptically coupled hypothalamic neurons, but not hippocampal neurons. These observations suggest that the hypocretins function within the CNS as neurotransmitters.

TRANCE is a novel ligand of the tumor necrosis factor receptor family that activates c-Jun N-terminal kinase in T cells.

A novel member of the tumor necrosis factor (TNF) cytokine family, designated TRANCE, was cloned during a search for apoptosis-regulatory genes using a somatic cell genetic approach in T cell hybridomas. The TRANCE gene encodes a type II membrane protein of 316 amino acids with a predicted molecular mass of 35 kDa. Its extracellular domain is most closely related to TRAIL, FasL, and TNF. TRANCE is an immediate early gene up-regulated by TCR stimulation and is controlled by calcineurin-regulated transcription factors. TRANCE is most highly expressed in thymus and lymph nodes but not in nonlymphoid tissues and is abundantly expressed in T cells but not in B cells. Cross-hybridization of the mouse cDNA to a human thymus library yielded the human homolog, which encodes a protein 83% identical to the mouse ectodomain. Human TRANCE was mapped to chromosome 13q14 while mouse TRANCE was located to the portion of mouse chromosome 14 syntenic with human chromosome 13q14. A recombinant soluble form of TRANCE composed of the entire ectodomain induced c-Jun N-terminal kinase (JNK) activation in T cells but not in splenic B cells or in bone marrow-derived dendritic cells. These results suggest a role for this TNF-related ligand in the regulation of the T cell-dependent immune response.

Are ruminal bacteria armed with bacteriocins?

The production of toxic compounds or antibiotics is a common component of intermicrobial competitive interactions, and many of these toxins have been adopted and adapted for the control of microbial populations. One class of these toxins, the bacteriocins, is a heterogeneous group of proteinaceous antibiotics that often display a high degree of target specificity, although many have a very wide spectrum of activity. To date, only limited information is available concerning the occurrence of bacteriocins among ruminal isolates or the sensitivity of ruminal microorganisms to exogenous bacteriocins. A survey of 50 strains of Butyrivibrio spp. isolated from a variety of sources (sheep, deer, and cattle) for bacteriocin production indicated a high incidence of bacteriocin-like activity (50%). Many of these inhibitory compounds appear to have a broad spectrum of activity, which suggests that bacteriocins may have a significant impact on both the competitive fitness of individual microbial strains within the rumen and on the overall structure of the microbial population within the rumen. Selected bacteriocins from lactic acid bacteria also were shown to have activity against Butyrivibrio spp. and may have application in ruminant systems. Bacteriocins may provide an alternative group of antibiotics for the manipulation of ruminal microbial populations. Bacteriocins have significant advantages over other antibiotics in target specificity, susceptibility to proteolytic digestion, possibility of genetic transfer and manipulation, and, in the case of some bacteriocins derived from lactic acid bacteria, a long history of safe use.

Heat Resistance of Listeria monocytogenes Scott A and HAL 957E1 in Various Liquid Egg Products †.

The thermal destruction of Listeria monocytogenes Scott A and HAL 957E1 (an egg isolate) was determined in five liquid egg products. The egg products used were liquid whole egg (LWE), liquid whole egg with 10% NaCl (LWEN), liquid whole egg with 10% sucrose (LWES), egg yolk with 10% NaCl (EYN), and egg yolk with 10% sucrose (EYS). Each of these products was inoculated with the individual strains of L. monocytogenes at initial populations of 106 colony-forming units (CFU)/ml and exposed to temperatures of up to 70°C for various periods of time from which thermal death time (TDT) curves were constructed. The Scott A strain tended to be more heat resistant than the egg isolate, HAL 957E1. The sensitivity of both strains to heating was influenced by the type of egg product in which they were suspended. The highest rates of kill were noted in LWE, while survival was best in those products supplemented with NaCl (LWEN and EYN). For the nonsalted products, time and temperature combinations equivalent to those required for the high-temperature short-time (HTST) pasteurization of liquid egg achieved 1.7 to 4.4 log-unit reductions of L. monocytogenes populations, while reductions for the salted products were only 0.2 to 0.6 log units. These results suggest that current HTST pasteurization conditions for liquid egg will not ensure a Listeria -free product, especially with products supplemented with NaCl.

The analysis of egg wash water for the rapid assessment of microbiological quality.

A total of 101 egg wash water samples from five different egg grading stations in eastern Ontario were analyzed for a variety of physical and chemical variables in an attempt to find a correlation with total bacterial counts. Temperature, pH, total chlorine, and percentage transmission at 600 nm (%T) were found to be significant variables, and a multiple regression equation was derived that accounted for 65% of the total variation. The equation was used to classify wash water samples as acceptable (< or = 10(5) cfu/mL) or unacceptable and correctly classified 77.2% of the samples. Classification of a second (validation) data set from 58 wash water samples was correctly predicted in 72% of the cases. The predictive value of the equation was especially good for those wash water samples obtained from stations that had used a chlorinated alkaline detergent, 90.4 and 100% for the modeling and validation data, respectively. Maintenance of wash water at recommended levels for temperature and pH (i.e., > or = 40 C and pH > or = 10) was insufficient to ensure bacterial numbers would be < or = 10(5) cfu/mL. Under normal operating conditions a minimum total available chlorine concentration of .45 mg/L should be maintained in wash water to ensure that bacterial numbers are kept at an acceptable level. Monitoring of temperature, pH, total chlorine, and %T will assist in maintaining wash water quality and minimize the number of samples returned to laboratories for microbiological analysis.

Survival of Listeria monocytogenes in egg washwater.

The viability of Listeria monocytogenes strains Scott A, 78-34, and 81-861 in artificial egg washwater at different temperatures and pH values was determined. After a 4-h incubation, less than a 1-log decrease in viability of strains Scott A and 78-34 was found at 33 degrees C with alkaline detergent (pH 8.0-10.5); however, up to a 3-log decrease in viable numbers was found in neutral pH controls lacking detergent. At 42 degrees C, survival was generally poorer; complete loss of viability (greater than 4-log decrease in viable numbers) was found within 2 h at neutral pH. Strain 81-861 was more sensitive to the test conditions than the other two strains. Viability of all strains was markedly lower in synthetic washwater at the lower pH values (pH 7-9) containing whole egg than washwater in which whole egg was omitted. The presence of whole egg appeared to have no effect on survival at pH 10.5. A limited survey of two egg wash facilities in Southeastern Ontario revealed Listeria innocua in environmental samples from both plants, and in washwater from one plant. These results suggest that Listeria spp. can survive normal commercial washwater conditions, and can be found in commercial egg wash plants.

Transcatheter embolization of a ruptured superior mesenteric artery aneurysm with Gianturco coils: a case report.

Reports of superior mesenteric artery embolization without the sequela of bowel ischemia or infarction are sparse. We report embolization of the main trunk of the superior mesenteric artery for control of a ruptured aneurysm without subsequent ischemia.