Differentiating responders and non-responders to rTMS treatment for depression after one week using resting EEG connectivity measures

BACKGROUND

Non-response to repetitive transcranial magnetic stimulation (rTMS) treatment for depression is costly for both patients and clinics. Simple and cheap methods to predict response would reduce this burden. Resting EEG measures differentiate responders from non-responders, so may have utility for response prediction.

METHODS

Fifty patients with treatment resistant depression and 21 controls had resting electroencephalography (EEG) recorded at baseline (BL). Patients underwent 5-8 weeks of rTMS treatment, with EEG recordings repeated at week 1 (W1). Forty-two participants had valid BL and W1 EEG data, and 12 were responders. Responders and non-responders were compared at BL and W1 in measures of theta (4-8 Hz) and alpha (8-13 Hz) power and connectivity, frontal theta cordance and alpha peak frequency. Control group comparisons were made for measures that differed between responders and non-responders. A machine learning algorithm assessed the potential to differentiate responders from non-responders using EEG measures in combination with change in depression scores from BL to W1.

RESULTS

Responders showed elevated theta connectivity across BL and W1. No other EEG measures differed between groups. Responders could be distinguished from non-responders with a mean sensitivity of 0.84 (p = 0.001) and specificity of 0.89 (p = 0.002) using cross-validated machine learning classification on the combination of all EEG and mood measures.

LIMITATIONS

The low response rate limited our sample size to only 12 responders.

CONCLUSION

Resting theta connectivity at BL and W1 differ between responders and non-responders, and show potential for predicting response to rTMS treatment for depression.

Reflections on current methods for evaluating skills during joint replacement surgery

Valid and reliable techniques for assessing performance are essential to surgical education, especially with the emergence of competency-based frameworks. Despite this, there is a paucity of adequate tools for the evaluation of skills required during joint replacement surgery. In this scoping review, we examine current methods for assessing surgeons’ competency in joint replacement procedures in both simulated and clinical environments. The ability of many of the tools currently in use to make valid, reliable and comprehensive assessments of performance is unclear. Furthermore, many simulation-based assessments have been criticised for a lack of transferability to the clinical setting. It is imperative that more effective methods of assessment are developed and implemented in order to improve our ability to evaluate the performance of skills relating to total joint replacement. This will enable educators to provide formative feedback to learners throughout the training process to ensure that they have attained core competencies upon completion of their training. This should help ensure positive patient outcomes as the surgical trainees enter independent practice.

Cite this article: Bone Joint J 2013;95-B:1445–9.

Keratin profiles of normal and malignant oral mucosa using exfoliative cytology

AIMS

To assess keratin profiles from smears of malignant and contralateral normal oral mucosa as part of the development of a screening procedure for oral cancer based on exfoliative cytology.

METHODS

Smears were taken from oral cancers (confirmed by biopsy) and from the contralateral site of 20 patients. Using a panel of antikeratin antibodies, the keratins expressed by these cells were identified using a standard immunocytochemical technique (Vectastain) and assessed on a 3 point scale.

RESULTS

Using chi 2 analysis, noticeable differences between the keratin profiles for malignant mucosal smears compared with the contralateral mucosal smears were found. This was particularly evident for the simple epithelial keratins.

CONCLUSION

Individual keratins can be identified in smears from oral cancers. The identification of simple epithelial keratins seem to be the best keratin markers associated with malignancy. Their detection within smears from oral lesions could be valuable in the early diagnosis of oral cancer.

Cytokeratin expression in oral exfoliative cytology: effect of temperature and fixation

The identification of keratin expression within oral cytology may be useful in the diagnosis of clinically suspicious oral mucosal lesions. There may be wide variation in the temperature at which such smears are stored, prior to processing. Conventionally, rapid fixation or storage at low temperatures is recommended to preserve kertin expression within tissue biopsies. No previous study has assessed whether this is true for oral cytology. Smears were taken from clinically normal buccal mucosa. For each temperature assessed (-70, -40, -22, +5, +20 and +26 degrees C), one smear was spray-fixed (Vale Smear Fix) and one air-dried, prior to storage for 4 days, and then staining with the pan-epithelial antikeratin antibody, LP34. Preservation of keratin expression was assessed as either weak (zero to few positive cells) or strong (most cells positive). The results were analysed using logistic regression with the statistical modelling package, GLIM. Over the range of temperatures studied, spray fixation did not appear to improve the identification of keratin expression. Although the best preservation was obtained at lower temperatures, keratin expression was still adequate after 4 days at 20 degrees C. Hence, a delay in processing of 4 days would still allow detectable expression in oral exfoliative cytology even at room temperature.

Thoracic splenosis. Diagnosis of a case by fine needle aspiration cytology

Fine needle aspiration cytology was used to study chest wall nodules in a patient who presented with fever, cough, pleuritic chest pain and cytomegalovirus infection and who had a previous history of abdominal trauma. The finding of splenic red pulp and white pulp in the aspirate, combined with the results of a radionucleotide liver-spleen scan, led to a diagnosis of thoracic splenosis, a relatively rare condition. Splenosis is thought to result from transplantation of splenic tissue after trauma and may provide some added protection against certain infectious conditions, both of which were present in this case.

Gastric mucosal protective mechanisms: roles of epithelial bicarbonate and mucus secretions

Secretion of HCO3 (amounting to 2-10% of maximum H+ secretion) in conjunction with the adherent mucus gel layer (functioning as a mixing barrier) protects gastric mucosa from luminal acid by a process of surface neutralization. Gastric HCO3 secretion is augmented by cholinergic agonists, prostaglandins and low luminal pH. Ulcerogens attenuate HCO3 secretion although passive diffusion of alkali consequent upon an increase in mucosal permeability may mask these inhibitory actions. Studies in vitro indicate that HCO3 transport in the stomach is dependent on oxidative metabolism, carbonic anhydrase activity and involves a CL exchange mechanism. Mucus, synthesized and released from epithelial cells, adheres to the mucosal surface as a thin (less than 80 microns in rat) but continuous gel layer. Prostaglandins and carbachol induced release of preformed mucus and thereby increase thickness, whereas acute exposure to ulcerogens has little effect on overall dimensions of the surface mucus layer. Measurements of pH gradients adjacent to gastric mucosa indicate that the disposal of luminal H+ occurs by extracellular neutralization. However, the fall in pH at the apical cell membrane when luminal pH is low (pH 1.5) suggests that while a mucus-bicarbonate barrier comprises the first line of mucosal defence, other factors are involved in the overall process of mucosal protection in the stomach.