Kazuo Otake

Metabolic Syndrome in Japanese Patients with Obstructive Sleep Apnea Syndrome

We investigated the prevalence of metabolic syndrome in patients with obstructive sleep apnea syndrome (OSAS) referred to a tertiary university–based medical center. A cross-sectional study of patients with a definite diagnosis of OSAS was performed using new diagnostic criteria for metabolic syndrome that were designed for the Japanese population. Clinical features and comorbidities related to metabolic syndrome were compared between 819 patients with OSAS (719 men and 100 women) and 89 control subjects without OSAS. Metabolic syndrome was significantly more common in the patients with OSAS than in the controls (49.5% vs. 22.0% for men, p<0.01; 32.0% vs. 6.7% for women, p<0.01). Men with OSAS (apnea-hypopnea index [AHI;[ge;5/h) had a higher risk of metabolic syndrome compared with controls (odds ratio [OR]: 3.47; 95% confidence interval [CI]: 1.84–6.53). There was a significantly increased risk of metabolic syndrome in men with moderate OSAS (AHI: 15–29.9/h) (OR: 2.83; 95% CI: 1.42–5.66) and men with severe OSAS (AHI≥30/h) (OR: 5.09; 95% CI: 2.67–9.71). Women with OSAS (AHI≥5/h) also had an increased risk of metabolic syndrome (OR: 6.59; 95% CI: 1.47–29.38), and the risk was significantly higher in women with severe OSAS (AHI≥30/h) (OR 14.00; 95% CI: 2.93–66.82). Risk factors for metabolic syndrome differed by gender: in men, age, body mass index (BMI), and OSAS (AHI≥15/h) were significantly associated with metabolic syndrome, whereas, in women, BMI was the only risk factor for metabolic syndrome. The increase of metabolic syndrome in Japanese OSAS patients suggests that this patient population is burdened with multiple risk factors for cardiovascular disease.

Effects of physiological cardiac pacing on sleep-disordered breathing in patients with chronic bradydysrhythmias

In six patients with chronic bradydysrhythmias, polysomnographies were performed before cardiac pacemaker implantation and over the week following implantation. A patient with third‐degree atrioventricular block (AVB) and two patients with sinus node dysfunction (SND) were associated with sleep‐disordered breathing (SDB). Their cardiac pacemaker therapies, with the increase in the average heart rate, led to a reduction of apnea–hypopnea index and/or an improvement of Cheyne‐Stokes breathing. It seems that chronic bradydysrhythmia is one of the causative factors leading to SDB.

Histologic study of age-related change in the posterior pituitary gland focusing on abnormal deposition of tau protein

We studied histologic findings of age‐related change in the posterior pituitary gland focusing specifically on abnormal deposition of tau protein. Posterior pituitary glands from a total of 201 patients with mean age of 72, range 15 to 100 years, were dissected at autopsy, and semiquantitative analysis of tau protein deposition in the posterior pituitaries was performed. We confirmed that tau protein deposition in the posterior pituitary appears histologically as either a ‘thread‐like’ or ‘dot’ form. In double staining using an anti‐neurofilament antibody and Gallyas‐Braak staining, Gallyas‐Braak‐positive structures were located in the neurite. The grade and the frequency of tau protein deposition were increased in accord with aging. An interrelation was observed between tau protein deposition in the brain and that in the posterior pituitary. In tauopathy diseases, tau protein deposition in the posterior lobe is advanced compared to that in non‐tauopathy diseases. The level of tau protein deposition in the hypothalamus was compared semi‐quantitatively with that in the posterior pituitary, and the levels correlated well. We suggest that in the posterior pituitary of elderly people, high frequency of occurrence of deposition of abnormal tau protein in the neurites may cause dysfunction of the pituitary gland.

Urinary β-2 Microglobulin Levels Sensitively Altered in an Osteomalacia Patient Receiving Add-on Adefovir Dipivoxil Therapy for Hepatitis B Virus Infection.

Adefovir dipivoxil (ADV) is effective for hepatitis B virus (HBV) infection; however, ADV may provoke renal injury resulting in osteomalacia, and this side effect is seldom recognized until bone fractures emerge. We herein present a 66-year-old woman with HBV infection who received ADV for 6 years. Although she exhibited no sign of bone fractures, her urinary β-2 microglobulin (β2MG) level increased to 83,837 μg/L and scintigraphy revealed minimal fractures of the third rib. ADV was subsequently reduced and her urinary β2MG rapidly fell to 3,637 μg/L. Conversely, her urinary N-acetyl-β-D-glucosaminidase, and serum phosphate, alkaline phosphatase levels did not respond.

Narcolepsy and other non‐SAS hypersomnia in sleep breathing disorders clinic

Four of the 708 snorers (0.56%), referred to our sleep breathing disorders clinic for the past 2 years were diagnosed as having narcolepsy‐cataplexy. Detecting HLA DRB1*1501/DQB1*0602 positive was informative for differentiating genuine narcolepsy from non‐sleep apnea syndrome (non‐SAS) hypersomnia in our clinic. A non‐SAS obese boy, diagnosed as having essential hypersomnia syndrome, was found to be HLA DRB1*1502/DQB1*0601 positive. His hypocretin concentration was 206 pg/mL in the cerebrospinal fluid.