Differences in the respiratory swings in COPD and ILD candidates for lung transplantation: a critical concern interpreting central pulmonary pressures

Background

In different clinical scenarios (i.e., obesity, COPD, exercise, mechanical ventilation), the swings in intrathoracic pressure are much larger, and end-expiratory (Pee) pressure can be significantly greater than atmospheric pressure. In these scenarios, the intravascular (Piv) pulmonary pressure can overestimate the true transmural (tm) value and it is recommended to read the average of Piv over a few respiratory cycles (Pmrc) [1–3].

Purpose

To analyze the respiratory swings and the effect of esophageal pressure (PES) (as a surrogate of intrathoracic pressure) on the reading of Piv tracings during the RHC at rest in COPD and interstitial lung disease (ILD) candidates for lung transplantation (LTx).

Methods

Thirty-one COPD (15) and ILD (16) candidates for LTx underwent RHC. End-expiratory and mean respiratory cycle measurements were obtained. The respiratory swing was estimated as the difference between maximum-minimum values of Piv. Ten patients (5 COPD/5 ILD) underwent simultaneous RHC and PES (Micro-balloon Esophageal Catheter, LATITUDE) to assess the Ptm (Piv − PES) [4].

Results

Both demographic (11F/20M, 60±7 yrs, 25±4 kg/m2) and hemodynamic data (mPAP 24±9 mmHg, pulmonary arterial occlusion pressure [PAOP] 8.6±4 mmHg, right atrial pressure [RAP] 5.2±3.9 mmHg, pulmonary vascular resistance 3.5±2.6 Wu) did not show significant differences between ILD and COPD except the cardiac index (ILD: 2.8±0.8 vs. COPD: 2.4±0.3 L/min/m2). Intravascular RAPee and PAOPee were higher than mrc values in both groups (Fig 1). However, transmural RAPee and PAOPee were similar to and correlated with (r=0.62 and 0.69, respectively; p<0.05) transmural Pmrc values. PESee values were positive in COPD and ILD (3.0±2.2 vs. 3.3±2.0 mmHg, NS). All ILD had negative PESmrc values and were lower than COPD patients (−1.76±1.7 vs. 0.78±1.6 mmHg, p<0.05). ILD PES swings were higher than COPD (10.9±3.7 vs. 8.3±1.4 mmHg), although it did not reach statistical significance (p=0.08). The lower forced vital capacity (%), the more negative the PESmrc (Fig 2A). ILD pts showed higher transmural to intravascular Pmrc (p<0.05) (Fig 2B).

Conclusion

End-expiratory intravascular RAP and PAOP overestimates the mean respiratory cycle pressures in COPD and ILD candidates for LTx. Averaging pulmonary vascular pressure tracings over the respiratory cycle would be accurate in COPD but could underestimate transmural values in ILD candidates for LTx. The reading of mean respiratory cycle pressure could not be enough to correct the pulmonary pressures measurement error associated with the presence of large swings of intrathoracic pressure.

Funding Acknowledgement

Type of funding sources: None.

Prognostic markers for colorectal cancer: estimating ploidy and stroma

Background

We report here the prognostic value of ploidy and digital tumour-stromal morphometric analyses using material from 2624 patients with early stage colorectal cancer (CRC).

Patients and methods

DNA content (ploidy) and stroma-tumour fraction were estimated using automated digital imaging systems and DNA was extracted from sections of formalin-fixed paraffin-embedded (FFPE) tissue for analysis of microsatellite instability. Samples were available from 1092 patients recruited to the QUASAR 2 trial and two large observational series (Gloucester, n = 954; Oslo University Hospital, n = 578). Resultant biomarkers were analysed for prognostic impact using 5-year cancer-specific survival (CSS) as the clinical end point.

Results

Ploidy and stroma-tumour fraction were significantly prognostic in a multivariate model adjusted for age, adjuvant treatment, and pathological T-stage in stage II patients, and the combination of ploidy and stroma-tumour fraction was found to stratify these patients into three clinically useful groups; 5-year CSS 90% versus 83% versus 73% [hazard ratio (HR) = 1.77 (95% confidence interval (95% CI): 1.13-2.77) and HR = 2.95 (95% CI: 1.73-5.03), P < 0.001].

Conclusion

A novel biomarker, combining estimates of ploidy and stroma-tumour fraction, sampled from FFPE tissue, identifies stage II CRC patients with low, intermediate or high risk of CRC disease specific death, and can reliably stratify clinically relevant patient sub-populations with differential risks of tumour recurrence and may support choice of adjuvant therapy for these individuals.

A study of genomic instability in early preneoplastic colonic lesions

It is difficult to explain the differential rates of progression of premalignant colonic lesions and differences in behaviour of morphologically similar lesions. Heterogeneity for microsatellite instability (MSI) and promoter methylation in driving these phenomena forward may explain this; however, no previous analysis has examined this in detail at the gland level, the smallest unit of colorectal premalignant lesions. We aimed to carry out an analysis of gland level genomic instability for MSI and promoter methylation. MSI occurred significantly more frequently (20%) in colonic glands than has previously been observed in whole colorectal polyps. Significant promoter methylation was seen in MLH1, PMS2, MLH3 and MSH3 as well as significant heterogeneity for both MSI and promoter methylation. Methylation and MSI may have a significant role in driving forward colorectal carcinogenesis, although in the case of MSI, this association is less clear as it occurs significantly more frequently than previously thought, and may simply be a passenger in the adenoma-carcinoma sequence. Promoter methylation in MLH1, MLH3, MSH3 and PMS2 was also found to be significantly associated with MSI and should be investigated further. A total of 273 colorectal glands (126 hyperplastic, 147 adenomatous) were isolated via laser capture microdissection (targeted at regions of MLH1 loss) from 93 colonic polyps and tested for MSI, and promoter methylation of the DNA mismatch repair genes MLH1, MSH2, MLH3, MSH6, PMS2, MGMT and MLH3 via methylation specific multiplex ligation-dependent probe amplification. Logistic regression modelling was then used to identify significant associations between promoter methylation and gland histological type and MSI status.

Oncolytic measles virus strains have significant antitumor activity against glioma stem cells

Glioblastoma (GBM) is the most common primary brain tumor in adults and has a dismal prognosis despite multimodality treatment. Given the resistance of glioma stem cells (GSC) to chemotherapy and radiation therapy, their eradication could prevent tumor recurrence. We sought to evaluate the antitumor activity of measles virus (MV) derivatives against GSC. We generated neurosphere cultures from patient-derived primary tumor GBM xenografts, and we characterized them for the GSC markers CD133, SOX2, Nestin, ATF5 and OLIG2. Using the MV-strains MV-GFP, MV-CEA and MV-NIS we demonstrated infection, viral replication and significant cytopathic effect in vitro against GSC lines. In tumorigenicity experiments, GBM44 GSC were infected with MV in vitro and subsequently implanted into the right caudate nucleus of nude mice: significant prolongation of survival in mice implanted with infected GSC was observed, compared with mock-infected controls (P=0.0483). In therapy experiments in GBM6 and GBM12 GSC xenograft models, there was significant prolongation of survival in MV-GFP-treated animals compared with inactivated virus-treated controls (GBM6 P=0.0021, GBM12 P=0.0416). Abundant syncytia and viral replication was demonstrated in tumors of MV-treated mice. Measles virus derivatives have significant antitumor activity against glioma-derived stem cells in vitro and in vivo.

The proportion of tumor-stroma as a strong prognosticator for stage II and III colon cancer patients: validation in the VICTOR trial

BACKGROUND

The intra-tumor stroma percentage in colon cancer (CC) patients has previously been reported by our group as a strong independent prognostic parameter. Patients with a high stroma percentage within the primary tumor have a poor prognosis.

PATIENTS AND METHODS

Tissue samples from the most invasive part of the primary tumor of 710 patients (52% Stage II, 48% Stage III) participating in the VICTOR trial were analyzed for their tumor-stroma percentage. Stroma-high (>50%) and stroma-low (≤50%) groups were evaluated with respect to survival times.

RESULTS

Overall and disease-free survival times (OS and DFS) were significantly lower in the stroma-high group (OS P<0.0001, hazard ratio (HR)=1.96; DFS P<0.0001, HR=2.15). The 5-year OS was 69.0% versus 83.4% and DFS 58.6% versus 77.3% for stroma-high versus stroma-low patients.

CONCLUSION

This study confirms the intra-tumor stroma ratio as a prognostic factor. This parameter could be a valuable and low cost addition to the TNM status and next to current high-risk parameters such as microsatellite instability status used in routine pathology reporting. When adding the stroma-parameter to the ASCO criteria, the rate of 'undertreated' patients dropped from 5.9% to 4.3%, the 'overtreated' increased with 6.8% but the correctly classified increased with an additional 14%.

[Capillary beta-hydroxybutyrate determination for monitoring diabetic ketoacidosis]

BACKGROUND AND OBJECTIVE

Diabetic ketoacidosis (DKA) is the most severe acute metabolic complication of type 1 diabetes mellitus. Insulin treatment is commonly guided by plasma glucose levels and changes in venous blood gases, while β-hydroxibutyrate (BHB) levels are rarely measured. The study objective was to evaluate the value of capillary BHB monitoring in the course and resolution of DKA.

PATIENTS AND METHODS

Thirty patients with type 1 diabetes admitted for DKA were enrolled. A standard protocol including monitoring of blood glucose, venous blood gases, semiquantitative ketonuria, and capillary BHB was used. Patients were divided into three groups by time to DKA resolution (group 1:<24 h, group 2: 24-48 h, group 3: >48 h), and BHB results were compared to all other biochemical measurements.

RESULTS

Mean laboratory results upon admission were: blood glucose 415 (standard deviation [SD] 106) mg/dL; bicarbonate 9.6 (SD 1.5) mmol/L; pH 7.13 (SD 0.04); BHB 4.33 (SD 0.48) mmol/L, and ketonuria 3+ in 22 patients and 4+ in 6. BHB correlated well with bicarbonate (r=-0.24139; P=0.0161) and pH (r=-0.56419; P<0.0001). BHB normalized earlier than ketonuria in all cases (group 1: 15.5 vs 18.8 hours P<0.05; group 2: 18.2 vs 23.5 hours P<0.01; group 3: 37.3 vs 41.7 hours P<0.01). Ten percent of patients still had ketonuria when blood ketone levels were already normal (<0.5 mmol/L).

CONCLUSION

BHB measurement is an easy, practical, and reliable monitoring method in DKA and may be used as a parameter to adjust insulin treatment.

Current and potential usefulness of pneumococcal urinary antigen detection in hospitalized patients with community-acquired pneumonia to guide antimicrobial therapy

BACKGROUND

The role of pneumococcal urinary antigen detection in the treatment of adults with community-acquired pneumonia (CAP) is not well defined. We assessed the usefulness of pneumococcal urinary antigen detection in the diagnosis and antimicrobial guidance in patients hospitalized with CAP.

METHODS

A prospective study of all adults hospitalized with CAP was performed from February 2007 through January 2008. To evaluate the accuracy of the test, we calculated its sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios. The gold standard used for diagnosis of pneumococcal pneumonia was isolation in blood or pleural fluid (definite diagnosis) and isolation in sputum (probable diagnosis). Antibiotic modifications, complications, and mortality were analyzed.

RESULTS

A total of 474 episodes of CAP were included. Streptococcus pneumoniae was the causative pathogen in 171 cases (36.1%). It was detected exclusively by urinary antigen test in 75 cases (43.8%). Sixty-nine patients had CAP caused by a pathogen other than S pneumoniae. Specificity was 96%, positive predictive value ranged from 88.8% to 96.5%, and the positive likelihood ratio ranged from 14.6 to 19.9. The results of the test led the clinicians to reduce the spectrum of antibiotics in 41 patients. Pneumonia was cured in all of them. Potentially, this optimization would be possible in the 75 patients diagnosed exclusively by the test.

CONCLUSION

When its findings are positive, the pneumococcal urinary antigen test is a useful tool in the treatment of hospitalized adult patients with CAP because it may allow the clinician to optimize antimicrobial therapy with good clinical outcomes.

Clonality assessment and clonal ordering of individual neoplastic crypts shows polyclonality of colorectal adenomas

BACKGROUND & AIMS

According to the somatic mutation theory, monoclonal colorectal lesions arise from sequential mutations in the progeny of a single stem cell. However, studies in a sex chromosome mixoploid mosaic (XO/XY) patient indicated that colorectal adenomas were polyclonal. We assessed adenoma clonality on an individual crypt basis and completed a genetic dependency analysis in carcinomas-in-adenomas to assess mutation order and timing.

METHODS

Polyp samples were analyzed from the XO/XY individual, patients with familial adenomatous polyposis and attenuated familial adenomatous polyposis, patients with small sporadic adenomas, and patients with sporadic carcinoma-in-adenomas. Clonality was analyzed using X/Y chromosome fluorescence in situ hybridization, analysis of 5q loss of heterozygosity in XO/XY tissue, and sequencing of adenomatous polyposis coli. Individual crypts and different phenotypic areas of carcinoma-in-adenoma lesions were analyzed for mutations in adenomatous polyposis coli, p53, and K-RAS; loss of heterozygosity at 5q, 17p, and 18q; and aneuploidy. Phylogenetic trees were constructed.

RESULTS

All familial adenomatous polyposis-associated adenomas and some sporadic lesions had polyclonal genetic defects. Some independent clones appeared to be maintained in advanced adenomas. No clear obligate order of genetic events was established. Top-down growth of dysplastic tissue into neighboring crypts was a possible mechanism of clonal competition.

CONCLUSIONS

Human colorectal microadenomas are polyclonal and may arise from a combination of host genetic features, mucosal exposures, and active crypt interactions. Analyses of tumor phylogenies show that most lesions undergo intermittent genetic homogenization, but heterotypic mutation patterns indicate that independent clonal evolution can occur throughout adenoma development. Based on observations of clonal ordering the requirement and timing of genetic events during neoplastic progression may be more variable than previously thought.

Culprit lesion and jeopardized myocardium: correlation between coronary angiography and single-photon emission computed tomography

BACKGROUND

The term "culprit lesion" is used to designate the coronary stenosis responsible for the symptoms of the patient with coronary artery disease. Its detection is essential when partial revascularization is contemplated. The term "jeopardized myocardium" is commonly used to mean the amount of myocardium put in danger by all the stenotic lesions; however, it should be restricted to the amount of myocardium that could become infarcted if only the most severe stenoses were occluded.

HYPOTHESIS

The aim of this study was to investigate (1) the agreement between coronary myocardial single-photon emission computed tomography (SPECT) and coronary angiography for the identification of the culprit lesion, and (2) the correlation of the two studies in the quantification of jeopardized myocardium.

METHODS

In all, 159 patients with coronary artery disease without previous myocardial infarction were included in the study. A score for myocardial SPECT was correlated with the angiographic scores by Califf and Gensini and with the authors' score which includes adjustment for collateral circulation.

RESULTS

The agreement between coronary angiography and SPECT for the diagnosis of the culprit lesion was 84% (87/104). The correlations between the scores of angiography and SPECT to assess jeopardized myocardium when all coronary stenoses were taken into account were significant (p < 0.0001), but their coefficients were suboptimal (r = 0.48 for Califf, r = 0.48 for Gensini, and r = 0.65 for the authors' score). When only the jeopardized myocardium resulting from the culprit lesion was considered, the correlation clearly improved (r = 0.85).

CONCLUSION

Thus, in 84% of patients with multivessel disease, an agreement between coronary angiography and myocardial SPECT for the diagnosis of the culprit lesion was observed. The correlation between these techniques for the quantification of jeopardized myocardium from the culprit lesion was satisfactory.

Prognostic factors in the diagnostic work-up of cancer patients in an internal medicine department: does age matter?

INTRODUCTION

Increasing life expectancy in the general population has led to a rise in the incidence of cancer and new challenges with regard to the diagnosis, therapy and prognosis of this disease.

AIM

To assess prognostic factors in the initial work-up of patients ultimately diagnosed with cancer in an Internal Medicine Service, particularly those related with age.

PATIENTS AND METHODS

A prospective study was undertaken with 224 patients ultimately diagnosed with cancer, as confirmed by histological or cytological study. The neoplasms included respiratory, gastrointestinal, genitourinary, metastatic adenocarcinoma of unknown origin, gynaecological, hepatobiliary and others. Before reaching the diagnosis, the following factors were investigated in all patients: functional status [Karnofsky Performance Status (KPS)], comorbidity (Charlson scale), body mass index (BMI), serum cholesterol and albumin concentrations, cognitive level (Mini-mental test), quality of life (Short Form 36 questionnaire), and extension of the disease according to established criteria. Survival at 1 year was analysed. Statistical analyses were done with spss 11.0 for Windows, using a forward stepwise (likelihood ratio) method to construct the model and a Cox multivariate model for the survival analysis.

RESULTS

A total of 224 patients, 167 men (74.5%) and 57 women (25.5%), with a mean age of 66.1 +/- 12.3 years were studied. KPS was >or= 70 in 84% and comorbidity was zero or one in 74%. BMI was 24.25 +/- 4.3, cholesterol 180.7 +/- 4.3, albumin 3.32 +/- 0.5 and Mini-mental score 25.4 +/- 3.7. Metastasis was seen in 131 patients (58.5%) and local disease in 93 cases (41.5%). One-year survival was 38.8% (87 patients) with a mean of 203.8 +/- 143 days. In the Cox analysis, the independent predictive factors for survival were KPS [hazard ratio (HR) = 0.951; 95% CI = 0.930-0.974; p < 0.01], metastatic dissemination (HR = 2.422; 95% CI = 1.643-3.571; p < 0.01), physical quality of life (HR = 0.978; 95% CI = 0.962-0.995; p < 0.01) and albumin (HR = 0.653; 95% CI = 0.455-0.936; p < 0.01).

CONCLUSIONS

In the initial work-up of patients ultimately diagnosed with cancer in an Internal Medicine Service, functional status, dissemination, the physical component in the quality of life scale and serum albumin levels were independent prognostic factors for survival. Age was not an independent prognostic factor and should not be used as a basis for adopting diagnostic or therapeutic decisions in these patients.

Coxsackieviruses and quasispecies theory: evolution of enteroviruses

Enterovirus populations display quasispecies dynamics, characterized by high rates of mutation and recombination, followed by competition, selection, and random drift acting on heterogeneous mutant spectra. Direct experimental evidence indicates that high mutation rates and complex mutant spectra can serve for the adaptation of enteroviruses to complex environments. Studies with the RNA-dependent RNA polymerase of picornaviruses suggest that multiple enzyme sites may influence the template-copying fidelity (incorporation of incorrect vs correct nucleotide) during RNA replication. Mutation and recombination are an unavoidable consequence of the molecular mechanisms inherent to the process of viral genome replication and underlie the diversification of enterovirus genomes as they multiply in human and animal hosts. The diversity of disease manifestations associated with closely related enteroviruses is probably attributable to profound biological effects of some mutations that, because of their limited number, do not necessarily affect the phylogenetic position of the virus. The combination of highly dynamic mutant spectra with unpredictable alterations of biological behavior by minimal genetic change defies classical classification schemes. The result is the need to update the grouping of enteroviruses quite frequently into genetic and serological types and subtypes. The tolerance of enterovirus genomes to remain replication-competent despite multiple mutation and recombination events encourages the engineering of live-attenuated vaccines. Also, the application of quasispecies theory to an understanding of the limits of viral genomes to accept mutations, together with an increasingly deeper understanding of the mechanisms of mutagenesis by nucleoside analogs, has paved the way for the application of lethal mutagenesis as a new antiviral strategy.

Rapid viral quasispecies evolution: implications for vaccine and drug strategies

High mutation rates occurring during replication allow RNA viruses to evolve rapidly and adapt continuously to new environments. This poses an enormous challenge to vaccine and drug development which, to be effective, must consid RNA virus variability and follow approaches that minimize the probability of escape or resistant mutants arising.

Impact of protein kinase PKR in cell biology: from antiviral to antiproliferative action

The double-stranded RNA-dependent protein kinase PKR is a critical mediator of the antiproliferative and antiviral effects exerted by interferons. Not only is PKR an effector molecule on the cellular response to double-stranded RNA, but it also integrates signals in response to Toll-like receptor activation, growth factors, and diverse cellular stresses. In this review, we provide a detailed picture on how signaling downstream of PKR unfolds and what are the ultimate consequences for the cell fate. PKR activation affects both transcription and translation. PKR phosphorylation of the alpha subunit of eukaryotic initiation factor 2 results in a blockade on translation initiation. However, PKR cannot avoid the translation of some cellular and viral mRNAs bearing special features in their 5' untranslated regions. In addition, PKR affects diverse transcriptional factors such as interferon regulatory factor 1, STATs, p53, activating transcription factor 3, and NF-kappaB. In particular, how PKR triggers a cascade of events involving IKK phosphorylation of IkappaB and NF-kappaB nuclear translocation has been intensively studied. At the cellular and organism levels PKR exerts antiproliferative effects, and it is a key antiviral agent. A point of convergence in both effects is that PKR activation results in apoptosis induction. The extent and strength of the antiviral action of PKR are clearly understood by the findings that unrelated viral proteins of animal viruses have evolved to inhibit PKR action by using diverse strategies. The case for the pathological consequences of the antiproliferative action of PKR is less understood, but therapeutic strategies aimed at targeting PKR are beginning to offer promising results.

Composición corporal de cabras criollas neuquinas en distintas notas de condición corporal

Se evaluó la relación existente entre las notas de condición corporal (CC) y la composición corporal en 20 cabras adultas de la raza Criolla Neuquina. Previo al sacrificio se registró el peso y la condición corporal lumbar (CCL), condición corporal esternal (CCE) y condición corporal caudal (CCC). Luego del sacrificio y el desuello, se separaron la grasa omental y mesentérica, procediendo luego a separar la grasa pericárdica. Finalmente se pesaron por separado todos los componentes grasos extraídos. La canal se pesó fresca y a las 24 h, luego del oreo. Se separó la grasa de pélvico-renal (KKCF), luego se dividió la canal en dos mitades iguales con sierra eléctrica y se pesó la canal izquierda. Para finalizar se llevó a cabo la disección de la media canal izquierda en sus componentes grasa subcutánea, grasa intermuscular, hueso y magro. Los valores del presente trabajo confirman la deposición prematura de la grasa intermuscular y mesentérica y tardía de la KKCF, subcutánea y omental. La mayor correlación correspondió a la KKCF, confirmando la conveniencia de utilizar este parámetro en la estimación del grado de engrasamiento. La mejor correlación entre las distintas notas de CC y los depósitos grasos expresados como proporción del peso vivo prefaena se obtuvo entre CCL y grasa total.

Actividad sexual en cabritos criollos neuquinos de la Patagonia Argentina

El conocimiento sobre el inicio de la pubertad y la maduración sexual en una raza o biotipo de animal doméstico constituye una herramienta necesaria para realizar un correcto manejo reproductivo. Los machos caprinos de diferentes razas presentan variación en el inicio de su actividad reproductiva. En 33 cabritos Criollos de la provincia del Neuquén, manejados en condiciones extensivas de producción (Lat. 41o 02' S Long. 70o 34' O), durante los meses de abril a julio (180-270 días de edad) se determinó la ruptura de la membrana prepucial y la capacidad de copulación, mediante su permanencia durante 10 minutos con cuatro hembras caprinas inducidas en estro mediante tratamiento hormonal. Durante los meses de abril a julio las tasas mensuales de cabritos que presentaron ruptura de su membrana prepucial y capacidad de copulación fueron 69,6; 78,3; 78,3; 82,6% y 18,7; 50; 61,1; 63,1% respectivamente. Para este período, los pesos vivos y circunferencias testiculares medias mensuales fueron 17,3 ± 0,07; 19,7 ± 0,07; 19,2 ± 0,06; 17,8 ± 0,06 kg y 16,5 ± 0,08; 16,7 ± 0,08; 17,6 ± 0,08; 17,2 ± 0,07 cm, respectivamente. Se determinó mensualmente que los cabritos sin membrana prepucial presentaron valores medios significativamente mayores en su peso vivo y circunferencia testicular con respecto a los cabritos con membrana prepucial. Asimismo, los cabritos con capacidad copulatoria tuvieron valores medios significativamente mayores en peso vivo y circunferencia testicular con respecto a los cabritos sin capacidad copulatoria. Se concluye que los cabritos Criollos Neuquinos presentan una ruptura progresiva de su membrana prepucial y un incremento en su capacidad copulatoria durante su primera estación reproductiva. El desarrollo sexual se presenta como un proceso gradual y estaría considerablemente asociado al peso vivo y a la circunferencia testicular.

KRAS and BRAF oncogenic mutations in MSS colorectal carcinoma progression

In sporadic colorectal cancer (CRC), KRAS are alternative to BRAF mutations and occur, respectively, in 30 and 10% of cases. Few reports addressed the association between KRAS-BRAF mutations and tumour progression specifically in sporadic microsatellite-stable (MSS) CRC. We screened KRAS and BRAF in 250 MSS primary CRC and 45 lymph node (LN) metastases and analysed the pathological features of the cases to understand the involvement of KRAS-BRAF activation in progression and metastasis. Forty-five per cent of primary MSS CRCs carried mutations in at least one of these genes and mutations were associated with wall invasion (P=0.02), presence and number of LN metastases (P=0.02 and P=0.03, respectively), distant metastases (P=0.004) and advanced stage (P=0.01). We demonstrated that KRAS and BRAF are alternative events in Tis and T1 MSS CRC and, KRAS rather than BRAF mutations, contributed to the progression of MSS CRC. The frequency of KRAS and/or BRAF mutations was higher in LN metastases than in primary carcinomas (P=0.0002). Mutated LN metastases displayed KRAS associated or not with BRAF mutations. BRAF mutations were never present as a single event. Concomitant KRAS and BRAF mutations increased along progression of MSS CRCs, suggesting that activation of both genes is likely to harbour a synergistic effect.

Population dynamics of RNA viruses: the essential contribution of mutant spectra

Cells and their viral and cellular parasites are genetically highly diverse, and their genomes contain signs of past and present variation and mobility. The great adaptive potential of viruses, conferred on them by high mutation rates and quasispecies dynamics, demands new strategies for viral disease prevention and control. This necessitates a more detailed knowledge of viral population structure and dynamics. Here we review studies with the important animal pathogen Foot-and-mouth disease virus (FMDV) that document modulating effects of the mutant spectra that compose viral populations. As a consequence of interactions within mutant spectra, enhanced mutagenesis may lead to viral extinction, and this is currently investigated as a new antiviral strategy, termed virus entry into error catastrophe.

Atypical presentation of aortic dissection secondary to a gunshot wound

We present a case of aortic dissection secondary to a gunshot wound. The traumatic aortic dissection in this patient occurred secondary to the cavitary forces produced by the bullet passing through the patient's chest. This is a rare phenomenon that could easily be missed if attention is placed only on the more obvious injuries.

Viruses as quasispecies: biological implications

During viral infections, the complex and dynamic distributions of variants, termed viral quasispecies, play a key role in the adaptability of viruses to changing environments and the fate of the population as a whole. Mutant spectra are continuously and avoidably generated during RNA genome replication, and they are not just a by-product of error-prone replication, devoid of biological relevance. On the contrary, current evidence indicates that mutant spectra contribute to viral pathogenesis, can modulate the expression of phenotypic traits by subpopulations of viruses, can include memory genomes that reflect the past evolutionary history of the viral lineage, and, furthermore, can participate in viral extinction through lethal mutagenesis. Also, mutant spectra are the target on which selection and random drift act to shape the long-term evolution of viruses. The biological relevance of mutant spectra is the central topic of this chapter.

BRAF screening as a low-cost effective strategy for simplifying HNPCC genetic testing

BACKGROUND

According to the international criteria for hereditary non-polyposis colorectal cancer (HNPCC) diagnostics, cancer patients with a family history or early onset of colorectal tumours showing high microsatellite instability (MSI-H) should receive genetic counselling and be offered testing for germline mutations in DNA repair genes, mainly MLH1 and MSH2. Recently, an oncogenic V600E hotspot mutation within BRAF, a kinase encoding gene from the RAS/RAF/MAPK pathway, has been found to be associated with sporadic MSI-H colon cancer, but its association with HNPCC remains to be further clarified.

METHODS

BRAF-V600E mutations were analysed by automatic sequencing in colorectal cancers from 206 sporadic cases with MSI-H and 111 HNPCC cases with known germline mutations in MLH1 and MSH2. In addition, 45 HNPCC cases showing abnormal immunostaining for MSH2 were also analysed.

RESULTS

The BRAF-V600E hotspot mutation was found in 40% (82/206) of the sporadic MSI-H tumours analysed but in none of the 111 tested HNPCC tumours or in the 45 cases showing abnormal MSH2 immunostaining.

CONCLUSIONS

Detection of the V600E mutation in a colorectal MSI-H tumour argues against the presence of a germline mutation in either the MLH1 or MSH2 gene. Therefore, screening of these mismatch repair (MMR) genes can be avoided in cases positive for V600E if no other significant evidence, such as fulfilment of the strict Amsterdam criteria, suggests MMR associated HNPCC. In this context, mutation analysis of the BRAF hotspot is a reliable, fast, and low cost strategy which simplifies genetic testing for HNPCC.

Phenotypic differentiation of exterior traits in local Criollo Goat Population in Patagonia (Argentina)

Abstract. The Neuquén-Criollo goat is a significant genetic resource, adapted to the singular harsh environment of North Patagonia. Its present gene pool was built up from different breeds since the Spanish colonization being Angora the latest introduced. High phenotypic diversity and their geographical distribution suggest a subdivision of this goat population into four close sub-areas. As phenotypic characterization was carried out on 827 Criollo adult goats. Analyse were based on fourteen quantitative (morphostructural) and eight qualitative (morphological) variables. Correspondence analyses for qualitative and canonical discriminant analysis for quantitative traits were performed, using hair types as classification variable. Results were consistent in differentiating the four considered sub-areas. Neuquen Criollo breed could be characterized in two ecotypes: Short and Long hair goats, a mixed type area and a crossbred area fulfil the types distribution. Principal divergence factors would be isolation, natural and artificial selection, transhumance and exotic breeds introduction.

International and Italian prognostic indices in follicular lymphoma

BACKGROUND AND OBJECTIVES

The International Prognostic Index (IPI), initially designed for aggressive lymphomas, has been successfully used in patients with follicular lymphoma (FL). The Italian Lymphoma Intergroup (ILI) created a new prognostic index specific for FL. The aim of this study was to compare which of these two indices is more useful when applied to a large group of FL patients.

DESIGN AND METHODS

Both indices, IPI (age >60 years, extranodal involvement >=2 sites, elevated lactate dehydrogenase, ECOG >=2, stage >=3) and ILI (age >60 years, extranodal involvement >=2 sites, elevated lactate dehydrogenase, male sex, B symptoms, erythrocyte sedimentation rate >=30 mm 1(st) hour) were calculated in a group of 398 FL patients. Overall survival (OS) and progression-free survival (PFS) associated with each prognostic group were calculated according to the Kaplan-Meier method.

RESULTS

The overall concordance between both indices was 73%. According to the IPI 122 patients (31%) were in the higher risk group, whereas according to the ILI 132 (33%) were; concordance between the high risk groups was 66%. The 10-years OS and PFS rates after applying the IPI system were 73% and 37%, respectively, in the low risk groups; 47% and 26%, in the intermediate risk groups and 25% and 2%, in the high risk groups (log-rank=69.2 and 41.3, respectively; p<0.0001). According to ILI index the 10-year OS and PFS were 60% and 34%, respectively, in the low risk groups; 59% and 30%, in the intermediate risk groups and 17% and 0%, in the high risk groups (log-rank=86.6 and 58.5, respectively; p<0.0001).

INTERPRETATION AND CONCLUSIONS

Both the IPI and ILI index, are useful for classifying FL patients into different risk groups. Although it seems that the ILI index has a higher discriminating power among groups, significant differences were not observed in identifying FL patients with a poor outcome.

Intravascular ultrasound of the elastic pulmonary arteries: a new approach for the evaluation of primary pulmonary hypertension

OBJECTIVE

To assess the structural and functional characteristics of pulmonary arteries by intravascular ultrasound (IVUS) in the setting of primary pulmonary hypertension, and to correlate the ultrasound findings with haemodynamic variables and mortality at follow up.

DESIGN

Prospective observational study.

SETTING

University hospital (tertiary referral centre).

PATIENTS

20 consecutive patients with primary pulmonary hypertension (16 female; mean (SD) age, 39 (14) years).

METHODS

Cardiac catheterisation and simultaneous IVUS of pulmonary artery branches at baseline and after infusion of epoprostenol.

RESULTS

33 pulmonary arteries with a mean diameter of 3.91 (0.80) mm were imaged, and wall thickening was observed in all cases, 64% being eccentric. Mean wall thickness was 0.37 (0.13) mm, percentage wall area 31.0 (9.3)%, pulsatility 14.6 (4.8)%, and pulmonary/elastic strain index 449 (174) mm Hg. No correlation was observed between IVUS findings and haemodynamic variables. Epoprostenol infusion increased pulsatility by 53% and decreased the pulmonary/elastic strain index by 41% (p = 0.0001), irrespective of haemodynamic changes. At 18 (12) months follow up, nine patients had died. A reduced pulsatility and an increased pulmonary/elastic strain index were associated with increased mortality at follow up (12.0 (4.4)% v 16.4 (4.4)%, p = 0.03; 369 (67) v 546 (216) mm Hg, p = 0.02).

CONCLUSIONS

IVUS demonstrated pulmonary artery wall abnormalities in all patients with primary pulmonary hypertension, mostly eccentric. The severity of the changes did not correlate with haemodynamic variables, and epoprostenol improved pulmonary vessel stiffness. There was an association between impaired pulmonary artery functional state as determined by IVUS and mortality at follow up.

Molecular indetermination in the transition to error catastrophe: systematic elimination of lymphocytic choriomeningitis virus through mutagenesis does not correlate linearly with large increases in mutant spectrum complexity

Studies with several RNA viruses have shown that enhanced mutagenesis resulted in decreases of infectivity or virus extinction, as predicted from virus entry into error catastrophe. Here we report that lymphocytic choriomeningitis virus, the prototype arenavirus, is extremely susceptible to extinction mutagenesis by the base analog 5-fluorouracil. Virus elimination was preceded by increases in complexity of the mutant spectra of treated populations. However, careful molecular comparison of the mutant spectra of several genomic segments suggests that the largest increases in mutation frequency do not predict virus extinction. Highly mutated viral genomes have escaped detection presumably because lymphocytic choriomeningitis virus replicates at or near the error threshold, and genomes in the transition toward error catastrophe may have an extremely short half-life and escape detection with state-of-the-art cloning and sequencing technologies.

The need for continuous immunosuppression with cyclosporin A to maintain an experimental model of uveal melanoma

We investigated the need for continuous immunosuppression to maintain experimental tumours derived from human uveal melanoma cells implanted in the choroid of pigmented rabbits. Two groups of pigmented rabbits immunosuppressed with cyclosporin A (CsA) were implanted with human uveal melanoma cells in the suprachoroidal space. After 5 weeks, CsA was discontinued in group 2. Animals were treated with prophylactic antibiotics and examined weekly for tumour growth, weight and secondary effects; blood urea nitrogen levels were measured every two weeks. Autopsies and histopathological studies were performed after death or euthanasia at the end of week 12. The difference between the groups in the development of ophthalmoscopic tumours was not statistically significant 5 weeks after implantation. Tumours in group 1 grew progressively throughout the experiment, whereas group 2 tumours showed marked regression 3-4 weeks after discontinuing CsA. Tumours in group 1 were significantly larger and had greater mitotic activity and showed more ciliary body, optic nerve and extrascleral invasion than tumours in group 2, which showed massive fibrosis, minimal mitotic activity and marked inflammatory cell infiltration. Continuous immunosuppression with CsA seems to be necessary to maintain tumour growth in this experimental model of uveal melanoma.

Lack of association between methylenetetrahydrofolate reductase (MTHFR) C677T and ischaemic heart disease (IHD): family-based association study in a Spanish population

The effect of the C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene, traditionally associated with ischaemic heart disease (IHD), was assessed in a Spanish population. The transmission disequilibrium test (TDT) was used to determine a possible association in a sample of 101 trios of IHD patients. The distribution of MTHFR genotypes was similar in the IHD subjects and the parental group; the TT genotype was present in 14.9% of IHD patients, as compared to 15.2% in the parents. The frequency of the T allele was also similar in IHD cases and parents (39.6% vs. 42.4%; p = 0.649). The TDT confirmed that the observed transmission of the T allele did not deviate significantly from the expected one (chi2 = 0.743; p > 0.4). Our TDT analysis clearly demonstrates a lack of association between the T allele of the C677T mutation in MTHFR and cardiovascular artery disease, both for the general group and for different risk subgroups (smokers, hypertension, male sex, overweight and type A behaviour pattern) in the Spanish population.

Prevalence and genetic heterogeneity of the reverse transcriptase T69S-S-X insertion in pretreated HIV-infected patients

The emergence of resistance to antiretroviral drugs represents one of the main reasons for treatment failure in HIV-infected persons. Resistance to multiple nucleoside analogues may result from rearrangements in the HIV pol gene, in particular one insertion of two amino acids at position 69. Herein, we examined the prevalence of this resistant genotype and its genetic heterogeneity in a group of 475 healthy pretreated HIV-positive subjects in Spain. Only 4 (0.8%) carried the codon 69 insertion. It was always found coupled to the T69S mutation. The extra amino acids were S-S in 2 subjects and S-G in the other 2. The presence of the insert was seen only in subjects previously exposed to AZT monotherapy for at least 6 months.