Comprehensive studies of carotid atherosclerosis

Carotid atherosclerosis is closely associated with the progression of other atherosclerotic conditions, including ischemic heart disease and cerebral infarction. Evaluation of carotid atherosclerosis is useful as an index of systemic atherosclerosis, and is used as a surrogate endpoint in a number of clinical studies. We have been investigating several risk factors on the progression of atherosclerosis, using the carotid arteries as a window on the arterial system in general.     

Quadriceps sarcopenia and visceral obesity are risk factors for postural instability in the middle‐aged to elderly population

Aim: Aging shifts body composition to comprising more fat and less muscle. Sarcopenia, particularly in the knee extensors, and obesity, particularly visceral obesity, either alone or in combination, may exacerbate age‐related physical disability. We investigated the association between age‐related quadriceps (Qc) sarcopenia and visceral obesity, as measured by cross‐sectional area (CSA), on postural instability. Methods: Mid‐thigh muscle CSA and abdominal visceral and subcutaneous fat area at the level of the umbilicus were assessed from computed tomography (CT) images in 410 apparently healthy independent middle‐aged to elderly subjects attending the medical check‐up program in Ehime University Hospital. Static postural instability using a posturograph and one‐leg standing time with eyes open were assessed. Results: Both abdominal visceral fat area and Qc muscle CSA corrected by body weight (BW) were associated with static postural instability, in addition to age and sex, while BW‐corrected Qc muscle CSA predicted a short one‐leg standing time. The combination of Qc sarcopenia, defined as greater than 1 standard deviation below the mean of a young group (age <60 years), and visceral obesity, defined as a visceral fat area of more than 100 cm², were associated with static postural instability, while Qc sarcopenia was related to a higher prevalence of one‐leg standing time of less than 30 s, irrespective of visceral obesity. Conclusion: Thigh Qc sarcopenia and visceral obesity are associated with postural instability in middle‐aged to elderly subjects. These findings suggest that age‐related, site‐specific fat and muscle mass alterations are associated with functional impairment. Geriatr Gerontol Int 2010; 10: 233–243.     

Associations between short one‐leg standing time and speed of sound of calcaneal bone in a general population: The Shimanami Health Promoting Program (J‐SHIPP) study

Aim: Loss of bone mass is a major cause of fracture in the elderly. One‐leg standing (OLS) time has been postulated to be predictive of reduced bone mass. Here, we conducted a cross‐sectional study to clarify whether OLS time measurements are associated with the speed of sound (SOS) of calcaneal bone independent of muscle mass in the lower extremity, a major confounding factor for the association, in a community‐dwelling population of middle‐aged to elderly subjects. Methods: The study subjects consisted of 770 apparently healthy middle‐aged to elderly community‐residents. Quantitative assessment of calcaneal bone was done using a quantitative ultrasound technique. OLS time with eyes open was measured with a maximum time of 60 s. Femoral muscle cross‐sectional area (CSA) was measured from a computed tomography image. Results: Subjects who could not stand 60 s on one leg (n = 192) showed significantly lower SOS (1487 ± 20, 1501 ± 24 m/s, P < 0.001). In addition, femoral muscle CSA was positively associated with SOS (male, r = 0.148, P < 0.01; female, r = 0.204, P < 0.001). However, multiple regression analysis adjusted for age, sex and muscle CSA identified short OLS time less than 60 s as an independent determinant of SOS in both male (P < 0.001) and female (P < 0.05) subjects. OLS time was significantly associated with posturograph‐measured mobility of the center of gravity. However, multiple regression analysis showed no significant correlation between balance impairment and SOS (P > 0.1). Conclusion: OLS time less than 60 s was significantly associated with reduced SOS independent of age, sex and muscle mass in the lower extremity.     

The relationship between the plasma concentration of bepridil and its efficacy in the treatment of atrial fibrillation in Japanese patients

Bepridil hydrochloride is used for treatment of atrial fibrillation (AF) in Japan. We investigated the relationship between plasma concentrations of bepridil just before dosing (Cbep) and its clinical efficacy in Japanese patients (n=36) with AF. Patients were treated orally with 100, 150 or 200 mg/d bepridil. Cbep were measured with UV-HPLC. In the first 14 d, when 150, 200, 250 or 300 ng/mL was set as a boundary value, the efficacy of bepridil was significantly higher in all patients with Cbep above than below the boundary value (p<0.05). In the maintenance stage (3 months longer after starting therapy), the efficacy of bepridil was significantly higher in patients with Cbep above than below 300 ng/mL (p=0.04). The clinical efficacy of bepridil was closely related to Cbep. The target value of Cbep to obtain a clinical benefit was approximately 300 ng/mL. Monitoring Cbep should be useful in the treatment of patients with AF.     

Rapid typing of influenza viruses using super high-speed quantitative real-time PCR

The development of a rapid and sensitive system for detecting influenza viruses is a high priority for controlling future epidemics and pandemics. Quantitative real-time PCR is often used for detecting various kinds of viruses; however, it requires more than 2h per run. Detection assays were performed with super high-speed RT-PCR (SHRT-PCR) developed according to a newly designed heating system. The new method uses a high-speed reaction (18s/cycle; 40 cycles in less than 20min) for typing influenza viruses. The detection limit of SHRT-PCR was 1 copy/reaction and 10(-1) plaque-forming unit/reaction for viruses in culture supernatants during 20min. Using SHRT-PCR, 86 strains of influenza viruses isolated by the Tokyo Metropolitan Institute of Public Health were tested; the results showed 100% sensitivity and specificity for each influenza A and B virus, and swine-origin influenza virus. Twenty-seven swabs collected from the pharyngeal mucosa of outpatients were also tested, showing positive signs for influenza virus on an immunochromatographic assay; the results between SHRT-PCR and immunochromatography exhibited 100% agreement for both positive and negative results. The rapid reaction time and high sensitivity of SHRT-PCR makes this technique well suited for monitoring epidemics and pre-pandemic influenza outbreaks.     

Light and electron microscopic histochemistry of the peroxidase activity in the secretory granules of the developing hamster submandibular gland

On the basis of light and electron microscopic observations of the post natal development of the hamster submandibular gland, granules in the acinar cells showed considerably variations in size and shape, as well as electron density of the peroxidase-positive reaction. The present study shows that secretory granules of the hamster submandibular gland undergo changes of area and of intensity for peroxidase activity 6 months after birth.