Implementation of intensity modulated radiotherapy for prostate cancer in a private radiotherapy service in Mexico

Intensity modulated radiation therapy (IMRT) allows physicians to deliver higher conformal doses to the tumour, while avoiding adjacent structures. As a result the probability of tumour control is higher and toxicity may be reduced. However, implementation of IMRT is highly complex and requires a rigorous quality assurance (QA) program both before and during treatment. The present article describes the process of implementing IMRT for localized prostate cancer in a radiation therapy department. In our experience, IMRT implementation requires careful planning due to the need to simultaneously implement specialized software, multifaceted QA programs, and training of the multidisciplinary team. Establishing standardized protocols and ensuring close collaboration between a multidisciplinary team is challenging but essential.     

Medium and temperature dependence of decarboxylase reactions inAeromonas spp.

Decarboxylase/dihydrolase activities inAeromonas spp. are important as diagnostic tools and indicators of enterotoxin production. We have analyzed the following media at 25°C, 29°C, and 37°C, respectively, for their ability to detect such activities: Møller's, Falkow's, and Fay and Barry's (F&B) containing ornithine, lysine, and arginine, respectively, as well as motility-indole-ornithine (MIO) medium and lysine decarboxylase broth with 0.1% agar (LDC). In order to retain ornithine negativity, but to get as much positivity as possible for arginine, optimal incubation conditions were 29°C for 96 h (Møller), 48 h (Falkow, MIO, and LDC), and 24 h (F&B). The F&B medium proved to be the most sensitive for the detection of lysine decarboxylase, a positive test being highly correlated with the two speciesA. hydrophila andA. sobria, and we suggest its use for routine detection of decarboxylase/dihydrolase activities.In memory of Dr. Sally Jo Rubin.     

Value of rRNA gene restriction patterns ofAeromonas spp. for epidemiological investigations

We have investigated the value of rRNA gene restriction (rDNA) patterns for strain discrimination in aeromonads isolated from clinical and environmental sources. Chromosomal DNA was purified and digested with restriction enzymesPst I andSma I, and the resulting fragments were separated by agarose gel electrophoresis and stained with ethidium bromide. The DNA was transferred to membranes (Southern blotting), where it was probed with biotinylated plasmid pKK3535 DNA. Hybridization bands were developed with the BluGene (BRL) kit. The resulting rDNA patterns were visually analyzed for similarities between epidemiologically related strains. Pattern heterogeneity was observed among unrelated strains of aeromonads of clinical and environmental origin, whereas homology was observed amongAeromonas caviae isolates from three siblings with gastroenteritis and between an infant and foster mother with acute gastroenteritis caused byA. caviae. Multiple isolates ofA. caviae from the same patient over more than 3 years produced homologous rDNA patterns which remained stable after 20 consecutive subcultures. Serotyping results for typable strains were consistent with strain designations derived by analysis of rDNA patterns. The specificity, reproducibility, stability, and ease of performance, especially with the nonisotopic probe, make ribotyping a valuable method for epidemiological investigations ofAeromonas infections.     

Is climate change causing the range contraction of Cape Rock-jumpers (Chaetops frenatus)?

Species distribution models often suggest strong links between climate and species' distribution boundaries and project large distribution shifts in response to climate change. However, attributing distribution shifts to climate change requires more than correlative models. One idea is to examine correlates of the processes that cause distribution shifts, namely colonization and local extinction, by using dynamic occupancy models. The Cape Rock-jumper (Chaetops frenatus) has disappeared over most of its distribution where temperatures are the highest. We used dynamic occupancy models to analyse Cape Rock-jumper distribution with respect to climate (mean temperature and precipitation over the warmest annual quarter), vegetation (proportion of natural vegetation, fynbos) and land-use type (protected areas). Detection/non-detection data were collected over two phases of the Southern African Bird Atlas Project (SABAP): 1987–1991 (SABAP1) and 2008–2014 (SABAP2). The model described the contraction of the Cape Rock-jumper's distribution between SABAP1 and SABAP2 well. Occupancy probability during SABAP1 increased with the proportion of fynbos and protected area per grid cell, and decreased with increases in mean temperature and precipitation over the warmest annual quarter. Mean extinction probability increased with mean temperature and precipitation over the warmest annual quarter, although the associated confidence intervals were wide. Nonetheless, our results showed a clear correlation between climate and the distribution boundaries of the Cape Rock-jumper, and in particular, the species' aversion for higher temperatures. The data were less conclusive on whether the observed range contraction was linked to climate change or not. Examining the processes underlying distribution shifts requires large datasets and should lead to a better understanding of the drivers of these shifts.     

Multistage density dependence in an amphibian

Density dependence is the major process keeping the sizes of natural populations within bounds. In organisms with complex life cycles, the stage at which density dependence occurs and whether it occurs in one or several life stages have important consequences for the dynamics of their populations. I manipulated density of pool frogs ( Rana lessonae) during the aquatic larval and the terrestrial juvenile stages and examined the effect on growth and survival until 1 year of age. High larval density, but not high juvenile density, led to smaller size at this age. Both larval and juvenile density led to reduced growth during the early juvenile stage, but the effect of the larval density appeared stronger than the effect of juvenile density. No density dependence in survival could be found. My results suggest that density dependence in both the larval and the terrestrial juvenile stage may play important roles in the regulation and dynamics of amphibian populations.     

Moult of three Palaearctic migrants in their West African winter quarters

Some theories about moult strategies of Palaearctic passerine migrants assume that birds adapt timing of moult to environmental conditions such as rainfall on their African wintering grounds. Species wintering in the northern tropics should limit moult to the period shortly after their arrival at the end of the rainy season. Passerine migrants wintering in West Africa should also moult more rapidly compared to related species or conspecific populations that moult elsewhere. We investigated the moult of melodious warblers Hippolais polyglotta, willow warblers Phylloscopus trochilus and pied flycatchers Ficedula hypoleuca wintering in Comoé National Park, Ivory Coast, between October 1994 and April 1998. In contrast to previous studies we did not restrict our analyses to moult of flight feathers but also included moult of body feathers. The results differed partially from the general assumptions of previous authors. Melodious warblers moulted twice: a complete moult shortly after their arrival, and a moult of body feathers and in some cases some tertials and secondaries in spring. Willow warblers moulting flight feathers were found between December and March with the majority moulting in January and February. Primary moult was not faster compared to populations moulting in central Africa and South Africa. Body feather moult varied strongly among individuals with birds in heavy moult between December and April. Pied flycatchers moulted body feathers and tertials between January and April. Birds with growing feathers were found throughout the whole period including the entire dry season. Moult strategies are thus not readily related to a few environmental factors in general and our results show that factors other than mere resource availability during certain times on the wintering grounds are likely to govern the timing of moult.Communicated by F.Bairlein     

Development and evaluation of a broad-range PCR-ELISA assay with Borrelia burgdorferi and Streptococcus pneumoniae as model organisms for reactive arthritis and bacterial meningitis

We have developed an assay based on a 16S rDNA broad-range amplification system followed by species-specific detection with a commercially available PCR-ELISA kit. B. burgdorferi and S. pneumoniae were used as model systems for arthritis and meningitis, respectively. The sensitivity of the B. burgdorferi assay was comparable to that of a species-specific PCR, whereas for S. pneumoniae the detection limit was one to three organisms as determined by plate counts. To specifically differentiate two species, two discontinuously located nucleotide differences in the region complementary to the capture probe are required during the detection step with the PCR-ELISA kit. A preliminary clinical evaluation was performed with eight specimens (joint and cerebrospinal fluids) previously shown to contain B. burgdorferi DNA. Except for one sample which was positive by the broad-range PCR-ELISA system only, the results were in agreement with those obtained by B. burgdorferi species-specific PCR. None of the 23 control samples were positive by either method. Thus, broad-range amplification in combination with the PCR-ELISA kit promises to be a sensitive and specific format for the detection of agents causing reactive arthritis, meningitis or other diseases associated with a limited number of different bacteria.