Sleep magnetic resonance imaging with electroencephalogram in obstructive sleep apnea syndrome.

OBJECTIVE: To evaluate the mechanism and level of upper airway obstruction in obstructive sleep apnea (OSA) patients during natural sleep, together with synchronous electroencephalogram and respiratory events registration at 3-Tesla magnetic resonance imaging (MRI) platform with high spatial and temporal resolution. STUDY DESIGN: A prospective cohort study of 20 randomly selected OSA patients. METHODS: Fifteen of 20 patients were able to complete spontaneous sleep during MRI. While asleep, dynamic MR images of pharynx were obtained in the midline sagittal view. During the scan, nasal and oral airflow, thoracoabdominal wall effort, and electroencephalogram were synchronously recorded. The physiologic data were retrospectively scored to identify periods of apneas and synchronized with dynamic MR images. RESULTS: In all 15 patients, the site of complete airway obstruction occurred at the retropalatal space. We noticed different positions of the soft palate during apneic events. In seven of 15 patients (47%), the soft palate was attached to the tongue base and moved backward, compressing the airway. In five of 15 patients (33%), the soft palate was detached from the tongue base and solely moved backward, compressing the airway. In three patients (20%), we recorded both mechanisms of complete airway obstruction. In cases with attached soft palate to the tongue base, we noticed significant narrowing of the retrolingual space during apneic events. CONCLUSION: We describe a novel mechanism of obstruction dependent on the position of soft palate. This mechanism might play an important role in selecting candidates for surgery or treatment with hypoglossal nerve stimulation. LEVEL OF EVIDENCE: 2b.

Osteoblastic bone metastases from renal cell carcinoma.

BACKGROUND: RCC accounts for only 2-3% of all cancers. Due to its' non-specific symptoms disease is often diagnosed in advanced stage. Disseminated RCC frequently produces bone metastases that are almost always highly destructive, hyper vascularized and purely osteolytic. CASE REPORT: In this article we describe a case of a 71-year old male patient with disseminated osteoblastic bone metastases from renal cell carcinoma (RCC), and present a short review of published literature reporting cases of osteoblastic bone metastases from RCC. Our patient presented with thoracic pain aggravated by movement. He was diagnosed with predominantly osteoblastic bone metastases in the skeleton of thoracic and lumbar vertebra along with metastases in iliac bones, ribs, humerus and clavicles. Initially, origin of bone metastases was unknown, but later a small tumor in patient's right kidney was identified. Microscopic evaluation of the open bone biopsy showed clear cell RCC with sarcomatoid differentiation. CONCLUSIONS: Although, due to its' rarity, RCC is not included in the primary differential diagnosis in patients with osteoblastic metastases, such rare cases suggest that RCC may be considered in the diagnosis when there no other primary tumor is found.

Percutaneous mechanical thrombectomy of superior mesenteric artery embolism.

BACKGROUND: The present series present three consecutive cases of successful percutaneous mechanical embolectomy in acute superior mesenteric artery ischemia. Superior mesenteric artery embolism is a rare abdominal emergency that commonly leads to bowel infarction and has a very high mortality rate. Prompt recognition and treatment are crucial for successful outcome. Endovascular therapeutic approach in patients with acute SMA embolism in median portion of its stem is proposed. CASE REPORTS: Three male patients had experienced a sudden abdominal pain and acute superior mesenteric artery embolism in median portion of its stem was revealed on computed tomography angiography. No signs of intestinal infarction were present. The decision for endovascular treatment was made in concordance with the surgeons. In one patient 6 French gauge Rotarex(®) device was used while in others 6 French gauge Aspirex(®) device were used. All patients experienced sudden relief of pain after the procedure with no signs of intestinal infarction. Minor procedural complication - rupture of a smaller branch of SMA during Aspirex(®) treatment was successfully managed by coiling while transient paralytic ileus presented in one patient resolved spontaneously. All three patients remained symptom-free with patent superior mesenteric artery during the follow-up period. CONCLUSIONS: Percutaneous mechanical thrombectomy seems to be a rapid and effective treatment of acute superior mesenteric artery embolism in median portion of its stem in absence of bowel necrosis. Follow-up of our patients showed excellent short- and long-term results.

The impact of sleep deprivation and nighttime light exposure on clock gene expression in humans.

AIM: To examine the effect of acute sleep deprivation under light conditions on the expression of two key clock genes, hPer2 and hBmal1, in peripheral blood mononuclear cells (PBMC) and on plasma melatonin and cortisol levels. METHODS: Blood samples were drawn from 6 healthy individuals at 4-hour intervals for three consecutive nights, including a night of total sleep deprivation (second night). The study was conducted in April-June 2006 at the University Medical Centre Ljubljana. RESULTS: We found a significant diurnal variation in hPer2 and hBmal1 expression levels under baseline (P<0.001, F=19.7, df=30 for hPer2 and P<0.001, F=17.6, df=30 for hBmal1) and sleep-deprived conditions (P<0.001, F=9.2, df=30 for hPer2 and P<0.001, F=13.2, df=30 for hBmal1). Statistical analysis with the single cosinor method revealed circadian variation of hPer2 under baseline and of hBmal1 under baseline and sleep-deprived conditions. The peak expression of hPer2 was at 13:55 ± 1:15 hours under baseline conditions and of hBmal1 at 16:08 ± 1:18 hours under baseline and at 17:13 ± 1:35 hours under sleep-deprived conditions. Individual cosinor analysis of hPer2 revealed a loss of circadian rhythm in 3 participants and a phase shift in 2 participants under sleep-deprived conditions. The plasma melatonin and cortisol rhythms confirmed a conventional alignment of the central circadian pacemaker to the habitual sleep/wake schedule. CONCLUSION: Our results suggest that 40-hour acute sleep deprivation under light conditions may affect the expression of hPer2 in PBMCs..