Effects of dominant and nondominant eyes in binocular rivalry.

PURPOSE: To investigate the relation between sighting and sensory eye dominance and attempt to quantitatively examine eye dominance using a balance technique based on binocular rivalry. METHODS: The durations of exclusive visibility of the dominant and nondominant eye target in binocular rivalry were measured in 14 subjects. The dominant eye was determined by using the hole-in-card test (sighting dominance). In study 1, contrast of the target in one eye was fixed at 100% and contrast of the target in the other eye was varied from 100% to 80% to 60% to 40% to 20%, when using rectangular gratings of 1, 2, and 4 cycles per degree (cpd) at 2 degrees, 4 degrees , and 8 degrees in size. In study 2, contrast of the target in the nondominant eye was fixed at 100% and contrast of the target in the dominant eye was varied from 100% to 80% to 60% to 40% to 20%, when using a rectangular grating of 2 cpd at 4 degrees in size. RESULTS: In study 1, the total duration of exclusive visibilities of the dominant eye target; that is, the target seen by the eye that had sighting dominance was longer compared with that of the nondominant eye target. When using rectangular gratings of 4 cpd, mean total duration of exclusive visibility of the dominant eye target was statistically longer than that of the nondominant eye target (p < 0.05). In study 2, reversals (in which duration of exclusive visibility of the nondominant eye becomes longer than the dominant eye when the contrast of the dominant eye target is decreased) were observed for all contrasts except for 100%. CONCLUSIONS: The dominant sighting eye identified by the hole-in-card test coincided with the dominant eye as determined by binocular rivalry. The contrast at which reversal occurs indicates the balance point of dominance and seems to be a useful quantitative indicator of eye dominance to clinical applications.     

Treatment with hypotensive agents affects the impaired relaxation of the penile corpus cavernosum in hypertensive rats.

Treatment of erectile dysfunction (ED) in hypertensive subjects remains to be formally established. There is currently no standardized treatment for ED in hypertensive subjects. In this study, we tested our hypothesis that hypotensive drugs would improve impaired relaxation in the corpus cavernosum of spontaneously hypertensive rats (SHR). Ten-week-old SHR was treated with amlodipine, imidapril or hydralazine for 4 weeks. Although all three drugs achieved an equivalent decrease in systolic blood pressure (SBP), only amlodipine and imidapril induced an increase in relaxation in response to electrical field stimulation (EFS) of the corpus cavernosum. In the case of amlodipine, this effect was dose- and SBP-dependent. Nitric oxide (NO)-dependent relaxation was increased by amlodipine over a wide range of EFS frequencies, was increased by imidapril at low EFS frequencies, and was decreased by hydralazine. Carbon monoxide (CO)-dependent relaxation was only increased by hydralazine, and this increase occurred over a wide range of frequencies. The NOx and cGMP levels in the EFS-stimulated corpus cavernosum were increased by amlodipine. Amlodipine did not affect the thiobarbituric acid-reacting substance levels in the serum and the corpus cavernosum, but did decrease superoxide dismutase activity in the tissue. Imidapril and hydralazine inhibited the acetylcholine-induced relaxation in the corpus cavernosum. Sodium nitroprusside-induced relaxation in the tissue was increased by amlodipine. All three agents similarly inhibited the phenylephrine-induced contraction. These results suggest that impaired neurogenic relaxation in the corpus cavernosum of SHR is improved by amlodipine and imidapril through an increase in the synthesis and/or release of neuronal NO, but not CO, and presumably the inhibited detumescence of erection, which is induced by norepinephrine being released from sympathetic neuron. These findings indicate that amlodipine and imidapril may ameliorate the decreased relaxation of cavernous smooth muscle in the setting of hypertension.     

Atrial septal defect repair through limited lateral thoracotomy in children

Objective We have developed a surgical method for atrial septal defect repair through a limited right lateral thoracotomy in which the incision line begins 2 cm caudal from the lower angle of the scapula and ends at the midaxial line, thereby improving patient satisfaction with the cosmetic results of treatment. Methods We performed a retrospective review of 28 patients who underwent isolated atrial septal defect repair through a limited right lateral thoracotomy between January 2002 and August 2004. The mean age and mean body weight at the time of the operation were 85.8 months (range 9–236 months) and 23.0 kg (range 8.0–56.0 kg), respectively. All repaired defects were the ostium secundum type. Results There was no operative or late mortality and no late morbidity after a mean follow-up of 26 months (range 12–41 months). Echocardiography showed no residual shunt in any of the patients. The mean length of the skin incision was 7.8 cm (range 5.0–11.0 cm), and almost all the patients had satisfactory cosmetic results. Conclusion The atrial septal defect repair through a limited right lateral thoracotomy in pediatric patients showed satisfactory surgical results and excellent cosmetic results.     

HTLV-I, HIV-I, and Hepatitis B and C Viruses in Western Province, Papua New Guinea: A Serological Survey

Seven hundred and twenty-three serum samples from individuals in 13 Gidra-speaking villages in Western Province, Papua New Guinea were tested for evidence of infection with human T- lymphotropic virus type I (HTLV-I), human immunodeficiency virus type I (HIV-I), hepatitis B virus (HBV) and hepatitis C virus (HCV). No samples were positive for antibodies to HIV-I. Antibodies to HTLV-I were found in 13 samples (1.8%), HBV surface antigens (HBsAg) were found in 86 samples (11.9%), and antibodies to HCV were found in 30 samples (4.1%). Six (46.2%) of 13 HTLV-I positive samples were positive for HCV or HBsAg. The seropositive rate varied in different villages and the incidence of HTLV-I and HCV was higher in coastal and riverine areas than inland.     

Mechanical power during maximal treadmill walking and running in young and elderly men

This study determined mechanical power during movements specific to maximal walking and running using a non-motorized treadmill in 38 elderly [69.4 (5.0) years] and 50 young [24.3 (3.4) years] men. The mean mechanical power over a period of time covering six steps, during which the belt velocity peaked and then kept almost plateau, was determined as a performance score in each of maximal walking (WP) and running (RP). In terms of the value relative to body mass, the relative difference between the two age groups was greater for RP (61.7%) than for WP (21.4%) or isometric knee extension (34.1%) and flexion torque (43.8%). In the two groups, WP was significantly (P<0.05) correlated to knee extension (r=0.582 for the elderly and r=0.392 for the young) and flexion torque (r=0.524 for the elderly and r=0.574 for the young). Similarly, RP was also significantly (P<0.05) correlated to knee extension (r=0.627 for the elderly and r=0.478 for the young) and flexion torque (r=0.500 for the elderly and r=0.281 for the young). In these relationships, the WP adjusted statistically by thigh muscle torque was similar in the two age groups. However, the corresponding value for RP was significantly higher in the young than in the elderly. The findings here indicate that: (1) the difference between the young and elderly men in mechanical power is greater during maximal running than maximal walking, and (2) although the thigh muscle torque contributes to the power production during the two maximal exercise modes in the two age groups, the RP is greater in the young than in the elderly regardless of the difference in the thigh muscle torque.     

Development of a high-level expression system for deuterium-labeled human serum albumin

We have developed an expression system for recombinant human serum albumin (rHSA) using methylotrophic yeast Pichia pastoris Mut(+) transformants together with the multiple cross-over integration of the vector containing human serum albumin (HSA). After 86 h of methanol induction, the secreted rHSA reached levels of approximately 320 mg/l in 100% H(2)O medium and approximately 180 mg/l in 70% D(2)O/30% H(2)O (v/v) medium in a fed-batch fermenter. The structures of the obtained rHSA and plasma-derived HSA (pHSA) were virtually identical as viewed from various physicochemical techniques such as HPLC, SDS gel electrophoresis, and CD. NMR peaks of the partially deuterium (D)-labeled rHSA (DrHSA) were quite sharp compared to those of pHSA due to suppression of the intramolecular nuclear Overhauser effect, promising further structural studies of the whole HSA molecule in the solution state using the recent NMR techniques.     

Muscle volume is a major determinant of joint torque in humans

Muscle force (MF) is linearly related to physiological cross-sectional area (CSA), which is obtained from muscle volume (MV) divided by fibre length. Taking into account the fact that joint torque (TQ) is determined by MF multiplied by the moment arm, the maximal TQ would be a function of MV. This proposition was tested in the present study by investigating the relationship between MV and TQ for elbow flexor (EF) and extensor (EE) muscles of 26 males. The MVs of EF and EE were determined from a series of muscle CSA by magnetic resonance imaging (MRI), and pennation angle (theta) and FL by ultrasonography (US). Maximal isometric TQ was measured at right angle of elbow joint for EF and EE. There was a highly significant correlation between MV and TQ both for EF and EE (r=0.95 and 0.96 respectively) compared with that between muscle CSA and TQ, suggesting the dependence of TQ on MV. Furthermore, prediction equations for MV (MVULT) from muscle thickness (MT) measured by US was developed with reference to MVMRI by the MRI on 26 subjects, and the equations were applied to estimate MV of healthy university students (CON; 160 males) and sports athletes (ATH; 99 males). There were significant linear relationships between MVULT and TQ both for EF (r=0.783) and EE (r=0.695) for all subjects (n=259). The MVULT was significantly higher in ATH (by 32% for EF and 33% for EE, respectively) than in CON. Similarly, significantly greater TQ was observed in ATH (by 35% for EF, 37% for EE, respectively). The theta for EE showed no difference between both groups (17.8 degrees for CON and 17.5 degrees for ATH). On the other hand, the TQ to MV ratio were identical for CON and ATH. The results reveal that the muscle volume of the upper arm is a major determinant of joint torque (TQ), regardless of athletic training.