Post-transcriptional control by global regulators of gene expression in bacteria

Several authentic or potential global regulators have recently been shown to act at the post-transcriptional level. This is the case for Hfq (HF-1), which is involved in the regulation of an increasing number of genes in Escherichia coli, and CsrA (RsmA) responsible for controlling the expression of genes for extracellular enzymes and secondary metabolism in Gram-negative bacteria. The cold-shock proteins of the CspA family are able to destabilise mRNA secondary structures at low temperature and, therefore, also seem to act post-transcriptionally. These findings illustrate a more general aspect of post-transcriptional control which, in the past, was generally restricted to regulators acting at a single target. The expression of several global transcriptional regulators, such as the stationary phase and heat-shock sigma factors and H-NS, have also recently been shown to be themselves under post-transcriptional control. These examples underline the importance of this type of control in bacterial gene regulation.

[Imaging in acute toxic encephalopathy]

Neuroimaging, particularly MR imaging, plays a major role for the diagnosis of many acute toxic encephalopathies. Toxic disorders are related to drugs (immunosuppressive agents, chemotherapeutic agents, anti-epileptic drugs, heroin...), to metals (lead, manganese, mercury...), and to industrial and environmental chemicals (solvent, carbon monoxide...). MR imaging with diffusion and perfusion imaging provides information regarding brain lesions induced by the toxic agents (vasogenic edema, cytotoxic edema, infarction, hemorrhage, demyelination...).

The relationship between translational control and mRNA degradation for the Escherichia coli threonyl-tRNA synthetase gene

Expression of thrS, the gene encoding Escherichia coli threonyl-tRNA synthetase, is negatively autoregulated at the translational level. Regulation is due to the binding of threonyl-tRNA synthetase to its own mRNA at a site called the operator, located immediately upstream of the initiation codon. The present work investigates the relationship between regulation and mRNA degradation. We show that two regulatory mutations, which increase thrS expression, cause an increase in the steady-state mRNA concentration. Unexpectedly, however, the half-life of thrS mRNA in the derepressed mutants is equal to that of the wild-type, indicating that mRNA stability is independent of the repression level. All our results can be explained if one assumes that thrS mRNA is either fully translated or immediately degraded. The immediately degraded RNAs are never detected due to their extremely short half-lives, while the fully translated messengers share the same half-lives, irrespective of the mutations. The increase in the steady-state level of thrS mRNA in the derepressed mutants is simply explained by an increase in the population of translated molecules, i.e. those never bound by the repressor, ThrRS. Despite this peculiarity, thrS mRNA degradation seems to follow the classical degradation pathway. Its stability is increased in a strain defective for RNase E, indicating that an endonucleolytic cleavage by this enzyme is the rate-limiting process in degradation. We also observe an accumulation of small fragments corresponding to the 5' end of the message in a strain defective for polynucleotide phosphorylase, indicating that, following the endonucleolytic cleavages, fragments are normally degraded by 3' to 5' exonucleolytic trimming. Although mRNA degradation was suspected to increase the efficiency of translational control based on several considerations, our results indicate that inhibition of mRNA degradation has no effect on the level of repression by ThrRS.

Effect of Preoperative Home-Based Exercise Training on Quality of Life After Lung Cancer Surgery: A Multicenter Randomized Controlled Trial

BACKGROUND

Preoperative exercise training is recommended for improvement of clinical outcomes after lung cancer (LC) surgery. However, its effectiveness in preventing postoperative decline in quality of life (QoL) remains unknown. This study investigated the effect of preoperative home-based exercise training (PHET) on QoL after LC surgery.

METHODS

Patients awaiting LC resection were randomized to PHET or a control group (CG). The PHET program combined aerobic and resistance exercise, with weekly telephone supervision. Primary outcome was QoL-assessed with the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire C30 (QLQ-C30) at baseline, before surgery, and 1 month after surgery. The secondary outcomes were hospital length of stay and physical performance. The main analysis included a factorial repeated-measures analysis of variance. Additionally, the proportion of patients experiencing clinical deterioration from baseline to post-surgery was assessed.

RESULTS

The study included 41 patients (68.1 ± 9.3 years; 68.3% male) in the intention-to-treat analysis (20 PHET patients, 21 CG patients). A significant group × time interaction was observed for global QoL (p = 0.004). Between-group differences in global QoL were statistically and clinically significant before surgery (mean difference [MD], 13.5 points; 95% confidence interval [CI], 2.4-24.6; p = 0.019) and after surgery (MD, 12.4 points; 95% CI, 1.3-23.4; p = 0.029), favoring PHET. Clinical deterioration of global QoL was reported by 71.4% of the CG patients compared with 30 % of the PHET patients (p = 0.003). Between-group differences in favor of PHET were found in pain and appetite loss as well as in physical, emotional and role functions after surgery (p < 0.05). Compared with CG, PHET was superior in improving preoperative five-times sit-to-stand and postoperative exercise capacity (p < 0.05). No between-group differences in other secondary outcomes were observed.

CONCLUSION

The study showed that PHET can effectively prevent the decline in QoL after LC surgery.

Tumeur mélanocytaire méningée primitive de grade intermédiaire : confrontation radio-pathologique

A case of primary meningeal intermediate grade melanocytic neoplasm involving the right C2 nerve root is presented. MRI findings may suggest this rare entity, especially when an extra-axial lesion is located in the posterior fossa or cervical spinal canal and demonstrates shortening of both T1 and T2. Eventually, definitive diagnosis relies on histology which demonstrates spindle-shaped melanocytic cells that are Fontana stained and positive for HMB:45 antigen. Cellularity, pleomorphism, mitotic rate, proliferation index and invasiveness are useful criteria to distinguish among the spectrum of primary melanocytic tumors of the central nervous system ranging from melanocytoma to malignant melanoma.

Home-Based Preoperative Exercise Training for Lung Cancer Patients Undergoing Surgery: A Feasibility Trial

BACKGROUND

Clinical guidelines recommend prehabilitation with exercise training to optimize recovery after lung cancer surgery. However, the lack of access to facility-based exercise programs is a major barrier to routine participation. This study aimed to assess the feasibility of a home-based exercise intervention before lung cancer resection.

METHODS

We conducted a prospective, two-site feasibility study, including patients scheduled for lung cancer surgery. Exercise prescription involved aerobic and resistance training with telephone-based supervision. The primary endpoint was overall feasibility (recruitment rate, retention rate, intervention adherence and acceptability). Secondary endpoints included safety and effects on health-related quality of life (HRQOL) and physical performance, evaluated at baseline, after the exercise intervention and 4-5 weeks after surgery.

RESULTS

Over three months, 15 patients were eligible, and all agreed to participate (recruitment rate: 100%). A total of 14 patients completed the exercise intervention, and 12 patients were evaluated postoperatively (retention rate: 80%). The median length of the exercise intervention was 3 weeks. Patients performed an aerobic and resistance training volume higher than prescribed (median adherence rates of 104% and 111%, respectively). A total of nine adverse events occurred during the intervention (Grade 1, n = 8; Grade 2, n = 1), the most common being shoulder pain. After the exercise intervention, significant improvements were observed in the HRQOL summary score (mean difference, 2.9; 95% confidence interval [CI], from 0.9 to 4.8; p = 0.049) and the five-times sit-to-stand test score (median difference, -1.5; 95% CI, from -2.1 to -0.9; p = 0.001). After surgery, no significant effects on HRQOL and physical performance were observed.

CONCLUSION

A short-term preoperative home-based exercise intervention is feasible before lung cancer resection and may enhance accessibility to prehabilitation. Clinical effectiveness should be investigated in future studies.

Bronchial schwannoma: a singular lesion as a cause of obstructive pneumonia

Bronchial schwannomas are very rare pulmonary lesions, but its awareness is important to reach correct diagnosis and decide proper intervention. Clinical and radiological characteristics are mainly unspecific and pathological examination usually provides the definite diagnosis. In small lesions, endoscopic approach may be sufficient, but in large lesions associated with organising pneumonia surgical intervention may be required. Prognosis is typically favourable. We describe a case of a woman, aged 66 years, with productive cough and sporadic haemoptysis, dyspnoea, anorexia, excessive sweating and weight loss with 2 months evolution. CT scan showed a soft tissue dense lesion on the left hilum with 3.75 cm with 18-Fludeoxyglucose uptake. Left upper lobectomy was performed. Gross examination revealed a polypoid mass without necrosis, histologically showing cellular dense (Antoni A) and less dense (Antoni B) areas with Verocay bodies, slightly pleomorphic spindle cells, without mitotic activity and positive for S100 protein on immunohistochemistry.

Mediastinal papillary thyroid carcinoma treated by video-assisted thoracic surgery - Case report

INTRODUCTION AND IMPORTANCE

The mediastinal ectopic thyroid gland is rare and usually asymptomatic. Ectopic thyroid tissue has malignant potential, but ectopic thyroid cancers are extremely rare, particularly mediastinal thyroid cancer, with only five cases reported in the literature.

CASE PRESENTATION

A 73 years-old male patient diagnosed with multinodular goitre with two FLUS cytology was summited to an uneventful total thyroidectomy. Pathology revealed 8 synchronous papillary carcinomas in both thyroid lobes. Follow-up identified persistent elevation of thyroglobulin. A cervical ultrasound and cervical and thoracic CT scan were performed, identifying a mediastinal tumour of 6 × 3 cm. Resection was performed by video-assisted thoracic surgery (VATS). Pathology identified an ectopic mediastinal thyroid with a 4 mm papillary microcarcinoma. Recovery was uneventful and the patient is currently asymptomatic.

CLINICAL DISCUSSION

There is no consensus on the best treatment strategy for mediastinal ectopic thyroid, but surgical resection is advised as being the only method allowing for a complete cure. Although both thoracotomy and sternotomy approaches have been usually used for mediastinal thyroid tumours resection, the thoracoscopic approach has been used with good results in recent years. Thoracoscopy has better visualization, less morbimortality, and faster recovery. Giant masses (>10 cm) are the only limitation for VATS.

CONCLUSION

Ectopic mediastinal thyroid is extremely rare, and its malignant transformation is even rarer. There is no consensus on the best treatment strategy, but surgical resection of the mediastinal thyroid is advised. VATS is a safe and feasible minimally invasive technique with good outcomes.

Cardiac telerehabilitation in a middle-income country: analysis of adherence, effectiveness and cost through a randomized clinical trial

BACKGROUND

The benefits of cardiac rehabilitation (CR) are already well established; however, such intervention has been underused, mainly in low- and middle-income countries.

AIM

To compare adherence, effectiveness, and cost of a home CR with the traditional CR (TCR) in a middle-income country (MIC).

DESIGN

Single-blind randomized control trial.

SETTING

A university hospital.

POPULATION

Individuals with coronary disease that were eligible were invited to participate. A randomized sample of 51 individuals was selected, where two participants were not included by not meeting inclusion criteria.

METHODS

The home-CR group participated in health education activities, carried out two supervised exercise sessions, and was instructed to carry out 58 sessions at home. Weekly telephone calls were made. The TCR group held 24 supervised exercise sessions and were instructed to carry out 36 sessions at home.

RESULTS

49 individuals (42 male, 56.37±10.35years) participated in the study, 23 in the home-CR group and 26 in the TCR group. After the intervention, adherence in the home-CR and TCR groups was 94.18% and 79.08%, respectively, with no significant difference (P=0.191). Both protocols were effective for the other variables, with no differences. The cost per patient for the service was lower in the home-CR (US$ 59.31) than in the TCR group (US$ 135.05).

CONCLUSIONS

CR performed at home in an MIC demonstrated similar adherence and effectiveness compared to the TCR program, but with a lower cost for the service. The results corroborate the possibility of using home CR programs, even in MICs, after exercise risk stratification and under remote supervision.

CLINICAL REHABILITATION IMPACT

Home-CR can contribute to overcome participants' barriers with compatible cost. Home-CR is effective in improving functional capacity and risk factors control. Perform risk stratification and remote supervision are essential to offer Home-CR.