The electronic nose as a rule-out test for tuberculosis in an indigenous population

INTRODUCTION

To end the tuberculosis (TB) epidemic, efficient diagnostic tools are needed. In a previous calibration study, a portable 'point of care' electronic nose device (Aeonose^TM ) proved to be a promising tool in a hospital setting. We evaluated this technology to detect TB in an indigenous population in Paraguay.

METHODS

A total of 131 participants were enrolled. eNose results were compared with anamnesis, physical examinations, chest radiography and mycobacterial cultures in individuals with signs and symptoms compatible with TB. The eNose analysis was performed in two stages: first, the training with a combination of a previous study population plus 47 participants from the new cohort (total n = 153), and second, the 'blind prediction' of 84 participants.

RESULTS

21% of all participants (n = 131) showed symptoms and/or chest radiography abnormalities suspicious of TB. No sputum samples resulted culture positive for Mycobacterium tuberculosis complex. Only one patient had a positive smell print analysis. In the training model, the specificity was 92% (95% confidence interval (CI): 85%-96%) and the negative predictive value (NPV) was 95%. In the blind prediction model, the specificity and the NPV were 99% (95% CI: 93%-99%) and 100%, respectively. Although the sensitivity and positive predictive value of the eNose could not be assessed in this cohort due to the small sample size, no active TB cases were found during a one year of follow-up period.

CONCLUSION

The eNose showed promising specificity and negative predictive value and might therefore be developed as a rule-out test for TB in vulnerable populations.

Recognizing spinal cord emergencies

Physicians who work in primary care settings and emergency departments frequently evaluate patients with neck and back pain. Spinal cord emergencies are uncommon, but injury must be recognized early so that the diagnosis can be quickly confirmed and treatment can be instituted to possibly prevent permanent loss of function. The differential diagnosis includes spinal cord compression secondary to vertebral fracture or space-occupying lesion, spinal infection or abscess, vascular or hematologic damage, severe disc herniation and spinal stenosis. The most important information in the assessment of a possible spinal cord emergency comes from the history and the clinical evaluation. Physicians must look for "red flags"--key historical and clinical clues that increase the likelihood of a serious underlying disorder. In considering diagnostic tests, physicians should apply the principles outlined in an algorithm for the evaluation of low back pain prepared by the Agency for Healthcare Research and Quality (formerly the Agency for Health Care Policy and Research). Computed tomography and magnetic resonance imaging can clearly define anatomy, but these studies are costly and have a high false-positive rate. Referral of high-risk patients to a neurologist or spine specialist may be indicated.

Severe bradycardia and bradypnea following vaginal oocyte retrieval: a possible toxic effect of paracervical mepivacaine

We report a case of a patient with a history of heart conduction disease, symptom-free and without treatment in the last years, who experienced a severe cardiac complication associated with in vitro fertilization (IVF) with vaginal oocyte retrieval (VOR). Eighty-five minutes after the VOR a severe bradycardia and bradypnea occurred, requiring an emergency application of a pacemaker. Presumably the condition occurred because of a toxic effect of the 400 mg of mepivacaine administered paracervically. It is concluded that in the paracervical anesthesia in the IVF cycles the therapeutic range should be scrupulously followed in patients with heart condition.

Cerebellar contusion associated with type I Chiari malformation following supratentorial head trauma: case report

Acute presentation of Type I Chiari malformation in children is distinctly rare. An 11 year old male suffered a trauma to the right temporal-parietal region in a tobogganing accident resulting in an open depressed skull fracture. Radiographic evaluation included a Computed Tomographic scan which also demonstrated a significant cerebellar contusion and the presence of subarachnoid hemorrhage in the region of craniovertebral junction. Magnetic Resonance imaging revealed an underlying Type I Chiari malformation. Somatosensory evoked responses shortly following the injury demonstrated slowing of conduction across the lower brainstem. The open depressed fracture was debrided and elevated. Subsequent observation resulted in slow improvement in neurological function. A followup somatosensory evoked potential study performed 21 days following the accident showed improvement in conduction across the craniovertebral junction. The tonsillar ectopia associated with Type I Chiari malformation may predispose to cerebellar, upper spinal and brainstem injury following supratentorial trauma.

Somatostatin analogues inhibit angiogenesis in the chick chorioallantoic membrane

The mechanism responsible for alterations in tumor growth following administration of somatostatin analogues is unknown. Somatostatin analogues, SMS 201-995 and RC-160, have demonstrated the potential to inhibit both tumor growth and vascularity, in vivo and in vitro. We hypothesized that SMS and RC-160 inhibit angiogenesis and this inhibition may alter tumor growth. To test this hypothesis, 2 mm methylcellulose disks containing concentrations of SMS 201-995 and RC-160 at 0, 0.5, 2.5, or 50 micrograms per disk, were implanted on the chorioallantoic membrane (CAM) of 6- to 7-day-old shell-less chick embryos. Inhibition of blood vessel growth in the region of the disk was visually assessed 24-36 hr following disk implantation and graded (0-4) based on the radius of the zone of inhibition from the center of the disk. The overall incidence of inhibition for the somatostatin analogues at concentrations of 0.5, 2.5, and 50 micrograms per disk was 13, 56, and 61% for SMS and 27, 49, and 68% for RC-160, respectively. Overall incidence of inhibition for the positive (inhibitory) control was 70.5% and those for buffer (negative) controls were 3-14%. Somatostatin analogues were associated in a dose-related fashion with both a greater percentage of inhibition of blood vessel growth and an increased grade of inhibition. Inhibition of angiogenesis may be a mechanism responsible for the tumor regression observed in vivo following SMS or RC-160 therapy.