Hyperbaric oxygen ameliorates delayed neuropsychiatric syndrome of carbon monoxide poisoning.

OBJECTIVES: Delayed neuropsychiatric syndrome (DNS) is characterized by mental impairment, motor dysfunction, dementia, or psychosis that develops between a few days and weeks after acute carbon monoxide (CO) poisoning. One possible mechanism responsible for CO-mediated encephalopathy involves oxidative stress, such as lipid peroxidation, caused by the cellular uptake of CO and which leads to an inflammatory cascade. There is no current effective treatment for DNS. We applied 8-40 sessions of hyperbaric oxygen therapy (HBO2) to patients with DNS and evaluated its effectiveness. METHODS: After admission, all patients were administered piracetam or bromocriptine, or both, and received HBO2. Neuropsychiatric tests included EEG, mini-mental status examination (MMSE), brain MRI, event-related potential (ERP), and brain perfusion scan (brain SPECT). Results of these tests were compared before and after HBO2, and the clinical features were monitored during this period. RESULTS: The symptoms of DNS for all patients improved significantly after HBOT. Although white matter changes remained evident in the brain MRI scans, other examinations such as EEG, MMSE, ERP, and 99mTc-ECD brain SPECT were nearly normal after HBOT. CONCLUSION: Our results suggest that HBO2 decreases the severity of impairment in patients with DNS. Although a large randomized trial is required to address the efficacy of this therapy, therapeutic application of HBO2 may be recommended in patients with DNS after CO poisoning.

Prediction of conversion from clinically isolated syndrome to clinically definite multiple sclerosis according to baseline MRI findings: comparison of revised McDonald criteria and Swanton modified criteria.

BACKGROUND: The International Panel on the Diagnosis of Multiple Sclerosis first incorporated abnormalities demonstrated by brain and spinal cord MRI into the diagnostic criteria (McDonald criteria) for multiple sclerosis (MS), which were later revised in 2005. In 2006, Swanton and colleagues modified the MRI criteria to simplify and speed the diagnosis. OBJECTIVE: The purpose of this study was to compare the ability of two sets of criteria (the revised McDonald MRI criteria and Swanton's modified criteria) to predict conversion from clinically isolated syndrome (CIS) to clinically definite multiple sclerosis (CDMS) from baseline MRI findings. METHODS: Sixty-four patients presenting with CIS suggestive of multiple sclerosis were recruited from 2001 to 2006 and followed up for at least 2 years. Their baseline brain and spinal cord MRI studies were retrospectively evaluated. The patients who developed CDMS during follow-up were treated as positive cases. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of the two MRI dissemination-in-space criteria were calculated. RESULTS: Thirty patients (46.9%) converted to CDMS. The sensitivity specificity, PPV, NPV and accuracy (%) of the revised McDonald criteria were 53, 100, 100, 71 and 78, respectively, while those for Swanton's modified criteria were 60, 100, 100, 74 and 81. CONCLUSIONS: In conclusion, Swanton's modified criteria are more sensitive and accurate (but not significantly so). However, Swanton's criteria are simpler to use and have equally high specificity and PPV.

Are the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation response dependent on global BOLD signals induced by hypercapnia in the functional MR imaging experiment? Experiments of long-duration hypercapnia and multilevel carbon dioxide concentration.

BACKGROUND AND PURPOSE: The relationship between the local blood oxygen level-dependent (BOLD) signals caused by neural stimulation (fBOLD) and the global BOLD signals induced by hypercapnia (hBOLD) has not been fully investigated. In this study, we examine whether fBOLD is modulated by hBOLD signals, by means of experiments using a relatively wide range of inhaled carbon dioxide (CO(2)) for a long duration of 5 minutes. MATERIALS AND METHODS: Ten healthy volunteers were recruited, each undergoing 6 separate experiments by inhaling gas mixtures with different fractions of CO(2) (room air, 3%-7%). Each experiment contained 3 phases, prehypercapnic, hypercapnic, and posthypercapnic, during which boxcar visual stimulus was given. The local fBOLD signals were measured from areas showing activation patterns highly correlated with the visual stimulus paradigm, whereas the global hBOLD signals were measured from areas showing no visual activations. Percentage changes in fBOLD during transient-state hypercapnia and steady-state hypercapnia were both investigated in response to varying degrees of hypercapnic perturbations. RESULTS: The hBOLD signals increased with increase of inhaled CO(2) fractions. The duration for the hBOLD signals to reach steady state prolonged with increase of inhaled CO(2) fractions. Normalized fBOLD ratio was inversely related to the inhaled CO(2) during steady-state hypercapnia but showed positive association with hBOLD during transient-state hypercapnia. CONCLUSION: Our study concludes that the steady-state fBOLD signal intensity is dependent on and inversely related to the hBOLD signals. Previous reports documenting independent and additive relationships between hBOLD and fBOLD may likely be due to transient-state observations.

Diffusion-tensor MR imaging for evaluation of the efficacy of hyperbaric oxygen therapy in patients with delayed neuropsychiatric syndrome caused by carbon monoxide inhalation.

The purpose of this study is to assess the efficacy of hyperbaric oxygen therapy (HBOT) in patients with delayed neuropsychiatric syndrome (DNS) caused by carbon monoxide (CO) inhalation using diffusion tensor magnetic resonance (MR) imaging and neuropsychological test. Conventional and diffusion tensor brain MR imaging exams were performed in six patients with DNS immediately before and 3 months after the HBOT to obtain fractional anisotropy (FA) values. Six age- and sex-matched normal control subjects also received MR exams for comparison. Mini-Mental State Examination (MMSE) was also performed in patients immediately before and 3 months after the HBOT. A significantly higher mean FA value was found in control subjects as compared with the patients both before and 3 months after the HBOT (P < 0.001). The mean FA value 3 months after the HBOT was also significantly higher than that before the HBOT in the patient group (P < 0.001). All of the patients regained full scores in the MMSE 3 months after the HBOT. Diffusion tensor MR imaging can be a quantitative method for the assessment of the white matter change and monitor the treatment response in patients of CO-induced DNS with a good clinical correlation. HBO may be an effective therapy for DNS.

Treatment of severe carinal stenosis with overlapping metallic endoprosthesis.

A 50-year-old man presented with respiratory distress from central airway compression secondary to malignant mediastinal adenopathy. The stenosis involved the carinal triangle and created residual luminal diameters of 6 mm, 6 mm, and pinhole in the distal trachea and right and left mainstem bronchi, respectively. Airway patency at the carina was restored successfully with a stenting method that uses two overlapping Wall stents.

Endobronchial stenting in patients requiring mechanical ventilation for major airway obstruction.

OBJECTIVE: To examine the value of therapeutic rigid bronchoscopy on subsequent ventilator weaning in ventilated patients with major airway obstruction. MATERIALS AND METHODS: Retrospective review of the medical records of patients who were receiving mechanical ventilation up to the time of rigid bronchoscopy over the period from September 1994 to January 1999. The setting is in an acute tertiary hospital. All patients underwent rigid bronchoscopy with endoscopic techniques (forceps removal, balloon dilation Nd:YAG laser resection and stent insertion) aimed at restoration of major airway patency. RESULTS: Seven patients were identified; 2 with benign stenosis and 5 with malignant stenosis. Six out of the 7 patients had presented with acute respiratory distress requiring emergent intubation, whilst 1 patient had extubation difficulties following general anaesthesia with endotracheal intubation. Three out of the 7 patients had previously failed extubation attempts. All 7 patients were successfully extubated within 48 hours following the procedure. CONCLUSIONS: Therapeutic rigid bronchoscopy is effective in the acute management of respiratory distress from central airway obstruction. Dramatic improvements in ventilatory status following therapeutic rigid bronchoscopy allow ventilator liberation in a select group of patients with an otherwise good performance status.

Active management of a patient with endstage pulmonary emphysema using lung volume reduction surgery and intensive rehabilitation.

INTRODUCTION: Lung volume reduction surgery (LVRS) and pulmonary rehabilitation are newer options available in the treatment of advanced emphysema. We describe the progress of our first local patient to have undergone these 2 new treatment modalities. CLINICAL PICTURE: A 65-year-old man with advanced emphysema, limited by crippling dyspnoea despite maximal medical therapy with inhaled bronchodilator therapy, methylxanthines and supplementary oxygen. TREATMENT: Physical reconditioning with a 4-week inpatient pulmonary rehabilitation programme, followed by LVRS and a further 6-week outpatient pulmonary rehabilitation. OUTCOME: Dramatic improvements in spirometric indices, arterial blood gases, exercise capacity and overall functional status. Improvements maintained at one-year follow up period. CONCLUSIONS: LVRS with pulmonary rehabilitation is an exciting new treatment option in a select group of patients with advanced emphysema. Their role in improving overall performance status and quality of life should be considered in patients otherwise considered to have reached the limits of medical therapy.

Neuroimaging of isolated and non-isolated third nerve palsies.

A variety of aetiologies may cause third nerve palsy (TNP), and some manifestations may herald neurological emergencies. This article describes and illustrates various diseases that lead to TNP.

The use of pseudo-dynamic magnetic resonance imaging for evaluating the relationship between temporomandibular joint anterior disc displacement and joint pain.

The relationship between temporomandibular joint (TMJ) pain and the magnetic resonance imaging (MRI) finding of articular disc displacement is debated. The purpose of this study is to investigate the correlation between TMJ pain and anterior disc displacement (ADD) using pseudo-dynamic MRI. A retrospective review of MRI studies was carried out on 130 TMJs in 65 patients presenting unilateral TMJ pain. The contralateral asymptomatic joints served as the control group. Bilateral oblique sagittal and coronal MRIs as well as pseudo-dynamic studies in the oblique sagittal plane were obtained. The disc-condyle relationship was divided into three subtypes (normal disc position, ADD with reduction, and ADD without reduction), based on the pseudo-dynamic MRI findings. Fisher's exact test was used to determine whether the TMJ pain was linked to ADD. The results showed that TMJ pain was significantly related to ADD (with and without reduction) compared to the group with a normal disc position (P=.0001). A significant correlation was found between TMJ pain and the ADD subtype without reduction, as compared to the ADD subtype with reduction (P=.0156). These data suggest that a displaced disc, particularly in the subtype without reduction, is an important source of pain.

Cauda equina syndrome and dural ectasia: rare manifestations in chronic ankylosing spondylitis.

Cauda equina syndrome (CES) is a rare manifestation in patients with long-standing ankylosing spondylitis (AS). We report a 57-year-old male patient with a 30-year history of AS who developed CES in the past 4 years. The CT and MRI examinations showed unique appearances of dural ectasia, multiple dorsal dural diverticula, erosion of the vertebral posterior elements, tethering of the conus medullaris to the dorsal aspect of the spinal canal and adhesion of the nerve roots of the cauda equina to the wall of the dural sac. A large dural defect was found at surgery. De-adhesion of the tethered conus medullaris was performed but without significant clinical improvement. The possible aetiologies of CES and dural ectasia in patients with chronic AS are discussed and the literature is reviewed.

Genistein-induced neuronal differentiation is associated with activation of extracellular signal-regulated kinases and upregulation of p21 and N-cadherin.

Neuronal differentiation in the mammalian CNS is driven by multiple events. When treated with retinoic acid (RA), hNTera-2 (NT-2) cells undergo postmitotic neuronal differentiation. Here, we show that a prolonged exposure of NT-2 cells with non-cytotoxic doses of genistein, a protein tyrosine kinase (PTK) inhibitor, induced differentiation of NT-2 cells. Additionally, genistein enhanced RA-induced neuronal differentiation by increasing the activation of extracellular signal-related kinase 1/2 (ERK1/2) via phosphorylation at Thr183 and Tyr185 in 3-7 days. Meanwhile, genistein also upregulated N-cadherin and p21 (a Cdk inhibitor), but downregulated proliferating cell nuclear antigen protein (PCNA). MEK1/2 inhibitors, such as PD98059 and U0126, reduced RA-induced ERK1/2 activity, but could not block the genistein effects. Our observations indicate that genistein-induced neuronal differentiation is not dependent of the MEK-ERK signaling cascade. Instead, genistein-upregulated ERK activation is likely due to this chemical's direct effect on chromosome and gene transcription, rather than its inhibition on tyrosine kinases. Failure of inhibition of ERK1/2 activation by the MEK1/2 inhibitors PD98059 and U0126 suggests presence of an unknown activator for ERK1/2 in neuronal cells.

The geography of the elderly in a modernizing society: the Hong Kong case.

PIP: The characteristics of the elderly population of Hong Kong are first described. Recent changes in the spatial distribution of the elderly are also detailed. The spatial distribution and internal migration patterns of the elderly are shown to be very similar to those of the population as a whole. The problems posed by the fact that many of the elderly are poorly educated and lowly paid are considered.^ieng