[Target volume segmentation of PET images by an iterative method based on threshold value]

OBJECTIVES

An automatic segmentation method is presented for PET images based on an iterative approximation by threshold value that includes the influence of both lesion size and background present during the acquisition.

MATERIAL AND METHODS

Optimal threshold values that represent a correct segmentation of volumes were determined based on a PET phantom study that contained different sizes spheres and different known radiation environments. These optimal values were normalized to background and adjusted by regression techniques to a two-variable function: lesion volume and signal-to-background ratio (SBR). This adjustment function was used to build an iterative segmentation method and then, based in this mention, a procedure of automatic delineation was proposed. This procedure was validated on phantom images and its viability was confirmed by retrospectively applying it on two oncology patients.

RESULTS

The resulting adjustment function obtained had a linear dependence with the SBR and was inversely proportional and negative with the volume. During the validation of the proposed method, it was found that the volume deviations respect to its real value and CT volume were below 10% and 9%, respectively, except for lesions with a volume below 0.6 ml.

CONCLUSIONS

The automatic segmentation method proposed can be applied in clinical practice to tumor radiotherapy treatment planning in a simple and reliable way with a precision close to the resolution of PET images.

Comparison of acquisition of resistant microorganisms and infections in critically-ill patients with and without malignancies

BACKGROUND

Patients with malignancies are often considered at risk of acquiring infections by resistant or potentially resistant microorganisms (RPRMs). However, data supporting this contention is scarce. We have compared critically ill patients with haematological malignancies (HM), solid tumours (ST) and without cancer (NC) in terms of acquisition of RPRMs, infections and mortality.

METHODS

Observational, prospective cohort study of patients admitted to a medical intensive care unit (ICU). Swabbing of nares, pharynx and rectum, and culture of respiratory secretions were obtained within 48 h of admission and thrice weekly thereafter. Clinical samples were obtained as deemed necessary by the attending physician. Clinical variables, severity scores on admission and exposures during ICU stay were also collected. Multivariable logistic regression analysis was used to evaluate ICU mortality.

RESULTS

Out of 969 included patients 127 (13.1%) had HM and 93 (9.6%) had ST. Patients with malignancies were more frequently exposed to central venous catheterization, methylprednisolone, and any antipseudomonal antibiotic whereas they were less commonly exposed to invasive mechanical ventilation. Patients with HM were more often admitted with an infection. There were no differences among groups in terms of RPRMs acquisition during ICU stay or prevalence of ICU-acquired infections due to any microorganism, including RPRMs. Having a HM was an independent predictor of mortality regardless of APACHE II score.

CONCLUSION

Critically ill cancer patients did not show a higher rate of RPRMs acquisition nor ICU-acquired infections. Mortality was higher in the HM group and it was not accurately predicted on admission by APACHE II score.

Genetic map of the primocane-fruiting and thornless traits of tetraploid blackberry

Blackberry primocane fruiting, fruiting on first-year canes, has the potential to expand blackberry production both seasonally and geographically. The incorporation of the primocane-fruiting trait into cultivars with desirable horticultural attributes is challenging due to its recessive nature and tetrasomic inheritance. Molecular marker-assisted selection has high potential to facilitate incorporation, because breeders already use morphological marker-assisted selection of seedlings without marginal cotyledonary hairs to identify progeny that will be thornless when mature. The development of a genetic linkage map with these two traits is the first step to utilizing molecular markers in breeding for thornless primocane-fruiting blackberry cultivars. A full-sib family segregating for thornlessness and primocane fruiting, from a cross between 'APF-12' and 'Arapaho', was used to construct the first genetic map of tetraploid blackberry. Segregation patterns of several dominant markers and the two phenotypic traits fit those expected uniquely with tetrasomic inheritance (e.g., 5:1, 11:1 and 35:1). Some loci showed significant double reduction frequencies, but genotypes that could have originated only from double reduction were not found. The map consists of seven linkage groups (LG) in each parent, consistent with the basic number of chromosomes (2n = 4x = 28). Naming of LG1-LG6 followed that of the recently revised system for raspberry using SSR markers in common between blackberry and raspberry, and LG7 was tentatively defined by default. The loci controlling primocane fruiting and thornlessness were not linked to each other; thornless/thorny, the S Locus, was mapped on LG4, and the primocane-/floricane-fruiting locus, named in this work the F Locus, on LG7.

A case of Japanese encephalitis in a 20 year-old Spanish sportsman, February 2013

We report a severe case of imported Japanese encephalitis (JE) in a healthy young Spanish traveller who developed symptoms after spending three weeks in a touristic area of Thailand. The patient was diagnosed in Thailand and subsequently transferred to Barcelona, Spain, where the Thai laboratory results were confirmed based on IgM serology. Although JE is a rare disease in travellers, this case illustrates the need for seeking travel medical advice before visiting tropical countries.

Celastrol suppresses tumor cell growth through targeting an AR-ERG-NF-κB pathway in TMPRSS2/ERG fusion gene expressing prostate cancer

The TMPRSS2/ERG (T/E) fusion gene is present in the majority of all prostate cancers (PCa). We have shown previously that NF-kB signaling is highly activated in these T/E fusion expressing cells via phosphorylation of NF-kB p65 Ser536 (p536). We therefore hypothesize that targeting NF-kB signaling may be an efficacious approach for the subgroup of PCas that carry T/E fusions. Celastrol is a well known NF-kB inhibitor, and thus may inhibit T/E fusion expressing PCa cell growth. We therefore evaluated Celastrol's effects in vitro and in vivo in VCaP cells, which express the T/E fusion gene. VCaP cells were treated with different concentrations of Celastrol and growth inhibition and target expression were evaluated. To test its ability to inhibit growth in vivo, 0.5 mg/kg Celastrol was used to treat mice bearing subcutaneous VCaP xenograft tumors. Our results show Celastrol can significantly inhibit the growth of T/E fusion expressing PCa cells both in vitro and in vivo through targeting three critical signaling pathways: AR, ERG and NF-kB in these cells. When mice received 0.5 mg/kg Celastrol for 4 times/week, significant growth inhibition was seen with no obvious toxicity or significant weight loss. Therefore, Celastrol is a promising candidate drug for T/E fusion expressing PCa. Our findings provide a novel strategy for the targeted therapy which may benefit the more than half of PCa patients who have T/E fusion expressing PCas.

Benchmarking in the process of donation after brain death: a methodology to identify best performer hospitals

A benchmarking approach was developed in Spain to identify and spread critical success factors in the process of donation after brain death. This paper describes the methodology to identify the best performer hospitals in the period 2003-2007 with 106 hospitals throughout the country participating in the project. The process of donation after brain death was structured into three phases: referral of possible donors after brain death (DBD) to critical care units (CCUs) from outside units, management of possible DBDs within the CCUs and obtaining consent for organ donation. Indicators to assess performance in each phase were constructed and the factors influencing these indicators were studied to ensure that comparable groups of hospitals could be established. Availability of neurosurgery and CCU resources had a positive impact on the referral of possible DBDs to CCUs and those hospitals with fewer annual potential DBDs more frequently achieved 100% consent rates. Hospitals were grouped into each subprocess according to influencing factors. Hospitals with the best results were identified for each phase and hospital group. The subsequent study of their practices will lead to the identification of critical factors for success, which implemented in an adapted way should fortunately lead to increasing organ availability.

Genetic alterations in poorly differentiated and undifferentiated thyroid carcinomas

Thyroid gland presents a wide spectrum of tumours derived from follicular cells that range from well differentiated, papillary and follicular carcinoma (PTC and FTC, respectively), usually carrying a good prognosis, to the clinically aggressive, poorly differentiated (PDTC) and undifferentiated thyroid carcinoma (UTC).It is usually accepted that PDTC and UTC occur either de novo or progress from a pre-existing well differentiated carcinoma through a multistep process of genetic and epigenetic changes that lead to clonal expansion and neoplastic development. Mutations and epigenetic alterations in PDTC and UTC are far from being totally clarified. Assuming that PDTC and UTC may derive from well differentiated thyroid carcinomas (WDTC), it is expected that some PDTC and UTC would harbour genetic alterations that are typical of PTC and FTC. This is the case for some molecular markers (BRAF and NRAS) that are present in WDTC, PDTC and UTC. Other genes, namely P53, are almost exclusively detected in less differentiated and undifferentiated thyroid tumours, supporting a diagnosis of PDTC or, much more often, UTC. Thyroid-specific rearrangements RET/PTC and PAX8/PPARγ, on the other hand, are rarely found in PDTC and UTC, suggesting that these genetic alterations do not predispose cells to dedifferentiation. In the present review we have summarized the molecular changes associated with the two most aggressive types of thyroid cancer.

RET/PTC rearrangement is prevalent in follicular Hürthle cell carcinomas

AIMS

The molecular alterations underlying follicular Hürthle cell carcinomas (FHCCs) are largely unknown. In an attempt to clarify this issue, we analysed a series of Hürthle cell tumours for the presence of RET/PTC and PAX8/PPARG rearrangements and BRAF, HRAS and NRAS mutations.

METHODS AND RESULTS

We investigated a series of 20 follicular Hürthle cell tumours [17 FHCCs and three follicular Hürthle cell adenomas (FHCAs)]. RET/PTC rearrangements were found in 33% of FHCAs and in 38% of FHCCs. All RET/PTC-positive FHCCs had a solid pattern of growth. PAX8/PPARG rearrangement was present in 27% of the FHCCs which displayed, in most cases, a follicular architecture. NRAS mutation was detected in one FHCC. An FHCC with a solid/microfollicular growth pattern scored positive for both RET/PTC and PAX8/PPARG rearrangement.

CONCLUSIONS

Our study has shown a significant association between RET/PTC rearrangements and FHCCs with a solid growth pattern, thus raising the possibility of using tyrosine kinase inhibitors for the treatment of patients with FHCCs, which are often refractory to radioiodine treatment.

Mortality and long term survival prognostic factors of patients with systemic autoimmune diseases admitted to an intensive care unit: a retrospective study

OBJECTIVES

To determine mortality and long-term survival factors in patients with systemic autoimmune diseases (SAD) admitted to the intensive care unit (ICU).

METHODS

Retrospective observational study including all consecutive patients with a diagnosis of any systemic autoimmune disease admitted to the medical ICU in a tertiary hospital between 1999 and 2007. Factors associated with reduced survival were identified by means of log rank test and backward stepwise Cox regression.

RESULTS

Thirty-seven patients (26 females) were included with median age being 44.3 years (interquartilic range [IQR]: 31.3). Sixteen (43.2%) patients had systemic lupus erythematosus, 9 (24.3%) had systemic vasculitis, 4 (10.8%) had systemic sclerosis and 4 (10.8%) had primary antiphospholipid syndrome. The main reason for ICU admission was autoimmune disease flare-up in 20 (54.0%) patients, followed by infections in 12 (32.4%). Median APACHE II at admission was 17 (IQR 7). At the end of follow-up, 15 (40.5%) patients died, 10 (27%) during hospitalisation (7 in the ICU) and 5 after hospital discharge. Factors associated with reduced long-term survival were: APACHE II score ≥18 (HR 6.02, 95% CI 1.76-20.62), age <45 years (HR 6.54, 95% CI 1.84-23.29), presence of any previous chronic disease (HR 18.20, 95% CI 3.72-88.96), and increase of corticosteroid therapy during ICU stay (HR 22.87, 95% CI 4.31-121.30).

CONCLUSIONS

The long-term survival of patients with systemic autoimmune diseases admitted to the ICU was related with age, higher APACHE II score, previous chronic diseases, and an increase in corticosteroids dose when comparing with previous ICU admissions.

Effect of beta blockers on central aortic pressure in African-Americans

The objective of this study was to evaluate the vascular effects of heart rate (HR) reduction with BB therapy in African Americans (AA). Beta-blockers (BB) offer less cardiovascular protection than other hypertensive drugs. Studies of Caucasian subjects suggest this may be due to an adverse effect of HR lowering on arterial wave reflection. We studied 506 subjects (age 63 ± 14 years, 52% were treated with BB). Central systolic (C-SBP) and pulse pressure (C-PP), augmented pressure (AP), and augmentation index (AI) were obtained via applanation tonometry (Sphygmocor). On univariate analysis, HR correlated inversely with BB use, C-SBP, AP, and AI (all P < .001), but not P-SBP. Multivariate analysis showed P-SBP and HR to be major determinants of C-SBP (R(2) = 0.95). Generalized linear model analysis showed higher C-SBP (P < .05) and C-PP (P = .04), but similar P-SBP (P = .24) in the BB group. After HR adjustment, differences in C-SBP, C-PP, AI, and AP were attenuated, suggesting HR to be a determinant of C-SBP. BB use is associated with higher C-SBP and lower PPA in hypertensive AA despite similar P-SBP. C-SBP is HR-dependent. HR reduction with BB accounts for less effective central blood pressure control in AA, similar to that reported in Caucasians.

Development of chickpea near-isogenic lines for Fusarium wilt

Four pairs of near-isogenic lines (NILs) of chickpea with resistance/susceptibility to Fusarium oxysporum f. sp. ciceris (Foc) have been developed in this study. These lines were produced by searching in advanced recombinant inbred lines (RILs) that are segregating for Foc race 5 based on a phenotypic screening. The sequence tagged microsatellite (STMS) marker TA59, closely linked to wilt resistance genes on linkage group 2 (LG2) of the chickpea map, was used to assist the selection of resistant or susceptible genotypes. The NILs were also characterized for disease reaction to Foc races 1A, 2, 3 and 4. Resistance, susceptibility and slow wilting reactions were found in these NILs. Our results suggest that more than one gene controls the resistance to race 5. Combination of the major gene foc-5 linked to TA59 with other gene/s appears to be required to complete resistance, and the absence of these unknown genes leads to slow wilting reactions. The independent differential responses to races 2 and 3 observed in three NILs could be explained as recombination events. This result suggests that foc-2 and foc-3 are delimiting points at opposite ends of a genomic region that includes the remaining foc genes and the TA59 marker. This set of NILs has great potential for studying the genetics and mechanisms of wilt resistance. In addition, the NIL RIP8-94-11 can be used as differential line for Foc race 3; it showed a clear resistance reaction to race 3 and susceptibility to the other Foc races.