Medida tridimensional del área del anillo tricúspide. Un nuevo criterio en la selección de candidatos a anuloplastia

Introduction and objectivesLate functional tricuspid regurgitation after rheumatic left-sided valve surgery is an important predictor of poor prognosis. This study investigated the usefulness and accuracy of 3-dimensional transthoracic echocardiography tricuspid area compared with conventional 2-dimensional diameter (2DD) for assessing significant tricuspid annulus dilatation, providing cutoff values that could be used in clinical practice to improve patient selection for surgery.MethodsWe prospectively included 109 patients with rheumatic heart disease in the absence of previous valve replacement. Tricuspid regurgitation was divided into 3 groups: mild, moderate, and severe. Optimal 3-dimensional area (3DA) and 2DD cutoff points for identification of significant tricuspid annulus dilatation were obtained and compared with current guideline thresholds. Predictive factors for 3DA dilatation were also assessed.ResultsOptimal cutoff points for both absolute and adjusted to body surface area (BSA) tricuspid annulus dilatation were identified (3DA: 10.4 cm², 6.5 cm²/m²; 2DD: 35 mm, 21 mm/m²); 3DA/BSA had the best diagnostic performance (AUC = 0.83). Three-dimensional transthoracic echocardiography tricuspid area helped to reclassify surgical indication in 14% of patients with mild tricuspid regurgitation (95%CI, 1%-15%; P = .03) and 37% with moderate tricuspid regurgitation (95%CI, 22%-37%; P < .0001), whereas 3DA/BSA changed surgery criteria in cases of mild tricuspid regurgitation (17%; 95%CI, 3%-17%; P = .01) compared with 2DD/BSA. On multivariable analysis, right and left atrial volumes and basal right ventricle diameter were independently correlated with 3DA.ConclusionsThe current 40 mm threshold underestimates tricuspid annulus dilatation. Although 21 mm/m² seems to be a reasonable criterion, the combination with 3DA assessment improves patient selection for surgery.Full English text available from:www.revespcardiol.org/en     

Accuracy of the Narrow-Band Imaging International Colorectal Endoscopic Classification System in Identification of Deep Invasion in Colorectal Polyps

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Patterns of disease in patients at a tertiary referral centre requiring reoperative parathyroidectomy

Introduction

Reoperative parathyroidectomy is required when there is persistent or recurrent hyperparathyroidism following the initial surgery (at least 5% of parathyroidectomies nationally). By convention, ‘persistent disease’ is defined as the situation where the patient has not been cured by the first operation. The term ‘recurrent hyperparathyroidism’ is used when the patient was confirmed to be biochemically cured for six months from the first operation but has hyperparathyroidism after this date. Reoperative surgery is associated with higher rates of postoperative complications as well as a greater rate of failure to cure. The aim of our study was to review our departmental experience of reoperative parathyroidectomy, with a view to identify patterns of disease persistence and recurrence.

Methods

Using a departmental database, patients were identified who had undergone reoperative parathyroidectomy between 2006 and 2014. All the pre, intra and postoperative information was documented including the operative note so as to record the location of the abnormal parathyroid gland found at reoperation.

Results

Almost two-thirds (63%) of patients had negative, equivocal or discordant conventional imaging so secondary investigative tools were required frequently. The majority of abnormal glands were found in eutopic locations. The most common locations for ectopic glands were intrathyroidal, mediastinal and intrathymic. A third (33%) of the patients had multigland disease and over a quarter (28%) had coexisting thyroid disease.

Conclusions

Persistent hyperparathyroidism represents a challenging patient subgroup for which access to all radiological modalities and intraoperative parathyroid hormone monitoring are required. Patient selection for reintervention is a key determinant in the reoperation cure rate.     

Specificity of mutagenesis by 4-aminobiphenyl: mutations at G residues in bacteriophage M13 DNA and G-->C transversions at a unique dG(8-ABP) lesion in single-stranded DNA

Mutagenesis by the human bladder carcinogen 4-aminobiphenyl (ABP) was studied in single-stranded DNA from a bacteriophage M13 cloning vector. In comparison to ABP lesions in double-stranded DNA, lesions in single- stranded DNA were approximately 70-fold more mutagenic and 50-fold more genotoxic. Sequencing analysis of ABP-induced mutations in the lacZ gene revealed exclusively base-pair substitutions, with over 80% of the mutations occurring at G sites; the G at position 6310 accounted for 25% of the observed mutations. Among the sequence changes at G sites, G- ->T transversions predominated, followed by G-->C transversions and G-- >A transitions. In order to further elucidate the mutagenic mechanism of ABP, an oligonucleotide containing the major DNA adduct, N- (deoxyguanosin-8-yl)-4-aminobiphenyl (dG(8-ABP)), was situated within the PstI site of a single-stranded M13 genome. After in vivo replication of the adduct containing ABP-modified and control (unadducted) genomes, the mutational frequency and mutational specificity of the dG(8-ABP) lesion were determined. The targeted mutational efficiency was approximately 0.01%, and the primary mutation observed was the G-->C transversion. Thus dG(8-ABP), albeit weakly mutagenic at the PstI site, can contribute to the mutational spectrum of ABP lesions.      

Missense mutations have unexpected consequences: The McArdle disease paradigm

McArdle disease is a disorder of muscle glycogen metabolism caused by mutations in the PYGM gene, encoding for the muscle‐specific isoform of glycogen phosphorylase (M‐GP). The activity of this enzyme is completely lost in patients’ muscle biopsies, when measured with a standard biochemical test which, does not allow to determine M‐GP protein levels. We aimed to determine M‐GP protein levels in the muscle of McArdle patients, by studying biopsies of 40 patients harboring a broad spectrum of PYGM mutations and 22 controls. Lack of M‐GP protein was found in muscle in the vast majority (95%) of patients, irrespective of the PYGM genotype, including those carrying missense mutations, with few exceptions. M‐GP protein biosynthesis is not being produced by PYGM mutations inducing premature termination codons (PTC), neither by most PYGM missense mutations. These findings explain the lack of PYGM genotype–phenotype correlation and have important implications for the design of molecular‐based therapeutic approaches.