Colonization pressure: a critical parameter in the epidemiology of antibiotic-resistant bacteria

ABSTRACT: The recognition of colonization pressure as an important risk factor for acquisition of antibiotic-resistant bacteria in the ICU, including Acinetobacter species, has major consequences for our understanding of risk factor analyses. Moreover, the importance of colonization pressure underpins the role of cross-transmission in the dynamics of antibiotic-resistant bacteria in the ICU, which has major consequences for the evaluation of the effectiveness of infection control measures.     

Spontaneous hypothermia on intensive care unit admission is a predictor of unfavorable neurological outcome in patients after resuscitation: an observational cohort study

Introduction  

A large number of patients resuscitated for primary cardiac arrest arrive in the intensive care unit (ICU) with a body temperature < 35.0°C. The aim of this observational cohort study was to determine the association between ICU admission temperature and neurological outcome in this patient group.     

Tumor Angiogenesis Phenotyping by Nanoparticle-facilitated Magnetic Resonance and Near-infrared Fluorescence Molecular Imaging

One of the challenges of tailored antiangiogenic therapy is the ability to adequately monitor the angiogenic activity of a malignancy in response to treatment. The α_vβ₃ integrin, highly overexpressed on newly formed tumor vessels, has been successfully used as a target for Arg-Gly-Asp (RGD)-functionalized nanoparticle contrast agents. In the present study, an RGD-functionalized nanocarrier was used to image ongoing angiogenesis in two different xenograft tumor models with varying intensities of angiogenesis (LS174T > EW7). To that end, iron oxide nanocrystals were included in the core of the nanoparticles to provide contrast for T₂*-weighted magnetic resonance imaging (MRI), whereas the fluorophore Cy7 was attached to the surface to enable near-infrared fluorescence (NIRF) imaging. The mouse tumor models were used to test the potential of the nanoparticle probe in combination with dual modality imaging for in vivo detection of tumor angiogenesis. Pre-contrast and post-contrast images (4 hours) were acquired at a 9.4-T MRI system and revealed significant differences in the nanoparticle accumulation patterns between the two tumor models. In the case of the highly vascularized LS174T tumors, the accumulation was more confined to the periphery of the tumors, where angiogenesis is predominantly occurring. NIRF imaging revealed significant differences in accumulation kinetics between the models. In conclusion, this technology can serve as an in vivo biomarker for antiangiogenesis treatment and angiogenesis phenotyping.     

Carcinoid tumors: iodine-131 MIBG scintigraphy

Eighty-two patients with pathologically proved carcinoid tumors were examined with iodine-131 metaio-dobenzylguanidine (MIBG) scintigraphy. Localization scores of I-131 MIBG accumulation in the primary tumor or metastatic site ranged from 0 to 3+ on the basis of comparison with normal liver. I-131 MIBG uptake varied greatly in different patients with carcinoid tumors. The localization scores in known tumor sites were related to the location of the primary tumor in the stomach (1-3+ in two of five patients), pancreas (1-3+ in four of five patients), cecum (3+ in two of two patients), appendix (0 in one of one patient), jejunum (0 in one of one patient), Meckel diverticulum (3+ in one of one patient), terminal ileum (2-3+ in 19 of 28 patients), bronchus (3+ in one of nine patients), thymus (1+ in one of two patients), and unknown (2-3+ in 18 of 28 patients). Tumors of midgut origin concentrated I-131 MIBG more frequently than those of foregut origin. Uptake of I-131 MIBG was more likely if neurohumor levels, particularly serum serotonin, were elevated. There was no relationship of I-131 MIBG uptake to carcinoid syndrome. I-131 MIBG is useful in the determination of the location and extent of some carcinoid tumors, particularly those of midgut origin.     

Non-disjunction of chromosome 18

A sample of 100 trisomy 18 conceptuses analysed separately and together with a published sample of 61 conceptuses confirms that an error in maternal meiosis II (MII) is the most frequent cause of non-disjunction for chromosome 18. This is unlike all other human trisomies that have been studied, which show a higher frequency in maternal meiosis I (MI). Maternal MI trisomy 18 shows a low frequency of recombination in proximal p and medial q, but not the reduction in proximal q observed in chromosome 21 MI non-disjunction. Maternal MII non-disjunction does not fit the entanglement model that predicts increased recombination, especially near the centromere. Whereas recent data on MII trisomy 21 show the predicted increase in recombination proximally, maternal MII trisomy 18 has non-significantly reduced recombination. Therefore, chromosome-specific factors must complicate the simple model of susceptible chiasma distributions interacting with age-dependent deterioration of the meiotic mechanism. For chromosome 18, 30% of tetrads are nullichiasmate in maternal MI non-disjunction, but nullichiasmates are not observed in maternal MII non-disjunction. Chiasma distributions from normal chromosome 18 meioses provide no evidence for normal disjunction from nullichiasmate tetrads. We extend this study to examine the remaining autosomes and find no evidence for normal disjunction from nullichiasmate tetrads generally.