Biomedical subjects

W Y Chiou

Publications and source records attributed to W Y Chiou.

5 recordsLinked to original sources

PubMed2000

Computerized rotational vestibular testing in normal subjects.

BACKGROUND: As an integral part of the contemporary vestibular testing battery, computerized vestibular rotational testing provides physiologic stimuli and quantitative evaluation of the vestibulo-ocular reflex function of the horizontal semicircular canals. Clinically, it is most commonly used in the sinusoidal harmonic acceleration test (SHAT) and velocity step test. Because the results for a given subject may vary when tested using different facilities, the purpose of this study is to establish the normative data for our laboratory. METHODS: Fifty-six normal subjects underwent the SHAT and velocity step test. Three parameters of SHAT--gain, phase and symmetry--were measured and recorded at 0.02, 0.05, 0.09 and 0.10 Hz. In the velocity step test, the three parameters of postrotatory nystagmus-time constant, maximum slow component eye velocity and directional preponderance were measured and recorded. RESULTS: The means +/- standard deviations of gain in the SHAT were 0.47 +/- 0.16 at 0.02 Hz, 0.50 +/- 0.16 at 0.05 Hz, 0.50 +/- 0.16 at 0.09 Hz and 0.53 +/- 0.17 at 0.10 Hz. The coefficient of variation for SHAT gain was 0.32. The time constant means and standard deviations in the velocity step test were 13.44 +/- 3.53 and 13.52 +/- 3.69 for clockwise and counterclockwise rotations, respectively. CONCLUSIONS: We conclude that computerized rotational vestibular testing is precise.

Adolescent↗

PubMed2000

Predictive efficacy of motion sickness history for airsickness.

BACKGROUND: Airsickness is a common problem in the early stage of flying training. It can be sufficiently severe to impair the student's flight performance and his ability to learn. Without adequate evaluation and rehabilitation, intractable airsickness symptoms will force student pilots to be permanently grounded. The purpose of this study was to evaluate the predictive efficacy of motion sickness history for airsickness of flight students. METHODS: A motion sickness history questionnaire with four different scores was used to predict airsickness of student pilots in the Air Force Academy. The questionnaire asked subjects questions about the severity and frequency of motion sickness symptom experienced in nine different motion sickness situations before and after 12 years of age. The results were grouped to four different scores. Pearson correlation and Student's t-test methods were used to evaluate the correlations of the four different scores. RESULTS: A total of 76 flight students in the class of 1997 who had under gone their flight-training course were included in this study. They were all healthy males with a mean age of 22.2 years (range, 20-24 years). The airsickness incidence of student pilots was 50%. The four different scores of motion sickness history questionnaire were highly correlated (r = 0.69-0.86, p < 0.01). The "after 12 years-of-age actually sick" score key had greater predictive validity for airsickness than the other motion sickness history questionnaire score keys and so did the "before 12 years-of-age feels sick" and "after 12 years-of-age feels sick" for no airsickness. CONCLUSIONS: The motion sickness history questionnaire was an efficient method to predict airsickness among Air Force student pilots.

Adult↗

PubMed1999

Roles of oxygen radicals and elastase in citric acid-induced airway constriction of guinea-pigs.

Antioxidants attenuate noncholinergic airway constriction. To further investigate the relationship between tachykinin-mediated airway constriction and oxygen radicals, we explored citric acid-induced bronchial constriction in 48 young Hartley strain guinea-pigs, divided into six groups: control; citric acid; hexa(sulphobutyl)fullerenes + citric acid; hexa(sulphobutyl)fullerenes + phosphoramidon + citric acid; dimethylthiourea (DMTU) + citric acid; and DMTU + phosphoramidon + citric acid. Hexa(sulphobutyl)fullerenes and DMTU are scavengers of oxygen radicals while phosphoramidon is an inhibitor of the major degradation enzyme for tachykinins. Animals were anaesthetized, paralyzed, and artificially ventilated. Each animal was given 50 breaths of 4 ml saline or citric acid aerosol. We measured dynamic respiratory compliance (Crs), forced expiratory volume in 0.1 (FEV0.1), and maximal expiratory flow at 30% total lung capacity (Vmax30) to evaluate the degree of airway constriction. Citric acid, but not saline, aerosol inhalation caused marked decreases in Crs, FEV0.1 and Vmax30, indicating marked airway constriction. This constriction was significantly attenuated by either hexa(sulphobutyl)fullerenes or by DMTU. In addition, phosphoramidon significantly reversed the attenuating action of hexa(sulphobutyl)fullerenes, but not that of DMTU. Citric acid aerosol inhalation caused increases in both lucigenin- and t-butyl hydroperoxide-initiated chemiluminescence counts, indicating citric acid-induced increase in oxygen radicals and decrease in antioxidants in bronchoalveolar lavage fluid. These alterations were significantly suppressed by either hexa(sulphobutyl)fullerenes or DMTU. An elastase inhibitor eglin-c also significantly attenuated citric acid-induced airway constriction, indicating the contributing role of elastase in this type of constriction. We conclude that both oxygen radicals and elastase play an important role in tachykinin-mediated, citric acid-induced airway constriction.

Animals↗

PubMed1993

Hazard potential of ejection with canopy fragmentation.

The hazard potential of ejection with canopy fragmentation was evaluated by horizontal sled tests. A series of 14 ejections of tandem seats with 1st or 95th percentile anthropometric dummies were performed at sled speeds of 0, 150, 350, and 600 knots. Canopy-mounted miniature detonating cords (MDC) were fired in nine and not fired in five ejections. Maximal impact loads on each dummy's neck, knees, and shoulders were measured, and noise levels inside and outside the helmet recorded. The acceleration waveform for each dummy was recorded and used to calculate a dynamic response index (DRI) to assess the risk of spinal injury. Impacts with canopy fragments during ejections resulted in minor visible damages to the dummies and their equipment regardless of MDC firing. It was noted that MDC firing significantly attenuated the mean neck load (231 +/- 63 kg, unfired, to 108 +/- 20 kg, fired, p < 0.05). Noise levels with MDC firing averaged 162 dB. The mean DRI of dummy Gz for the small dummies was significantly greater than for large dummies (20.8 +/- 0.44 and 18.05 +/- 0.98, respectively, p < 0.05). We conclude that superficial injuries to ejecting pilots and their equipment is not a hazard with the canopy fragmentation system; however, spinal injury may occur at rates of 5 to 50% depending on the size of the pilot.

Aircraft↗

PubMedDate not supplied

Imprint cytology of nasopharyngeal biopsies.

OBJECTIVE: To use an instant cytologic diagnostic method to examine touch imprints of nasopharyngeal (NP) biopsies. This method aimed to ensure the adequacy of biopsied specimens for histologic examination. This paper describes the morphologic findings of NP lesions examined by this method. STUDY DESIGN: Imprints were made from NP biopsies from patients suspicious for nasopharyngeal carcinoma (NPC). These imprints were air dried, stained with Diff-Quik and examined immediately. The adequacy of the specimens was assessed, and the findings of the imprints were interpreted as positive-, negative- or suspicious for NPC. Repeat biopsies and cytologic studies were done as indicated. In selected cases, immunocytochemical staining was done to identify cells on the imprints. Histologic examination of the biopsied specimens served as the control. RESULTS: With this method we could interpret the imprints within five minutes of their receipt and determine if repeat biopsy was needed. In benign lesions, the imprints often contained many cells, most mature and reactive lymphocytes. These cells and the numerous lymphoglandular bodies (fragments of lymphoid cytoplasm) intermingled with the ciliated and squamous epithelial cells. In cases of NPC, the appearance was discrete, or clusters of, carcinoma cells or naked nuclei. They were less cellular than those of benign lesions. The lymphocytes were markedly depleted. Cells of dubious lineage were identified by the additional use of immunocytochemical studies. CONCLUSION: Cytologic examination of imprints of NP biopsies helps to determine the adequacy of the specimen for histologic examination. It is a rapid, practical method with high diagnostic accuracy.

Biopsy↗