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Biomedical subjects

D Han

Publications and source records attributed to D Han.

At least 199 records · Page 11Linked to original sources
PubMed1991

Respirator fit and protection through determination of air and particle leakage.

A laboratory technique for determining the respirator protection factor from a test of fit is described. A dynamic pressure test quantifies the air flow through the leak. Calibration data, stored in a computer, relate the contaminant influx to this air flow, and a similar pressure test determines the flow through the respirator cartridges and, therefore, the dilution characteristics. Contaminant removal characteristics of the cartridges are stored in the computer. The contaminant penetration is calculated from these data on flow and removal efficiency. Through specification of the aerosol size distribution and the method of measurement, protection factors are calculated for specific work environments, work loads and respirator cartridges. The protection factor is shown to be highly dependent on the method of measuring the contaminant and on the cartridges used.

Air Pollutants↗
PubMed1991

[Intrauterine adhesion and ovulatory disorder following induced abortion].

Follicular stimulating hormone, luteinizing hormone, prolactin, estradiol and progesterone were measured by radioimmunoassay in 34 patients with those from 34 normal cycling women after induced abortion. The result showed that the anovulatory incidence of the patients (20.6%) was significantly higher than that of the controls (2.8%) (P less than 0.05). Increased prolactin and premature ovarian failure might be responsible for the anovulatory disorder, resulting in unsatisfactory restoration of fertility. It is suggested that the low success rate in treating patients with intrauterine adhesion after induced abortion may be due to premature ovarian failure and hyperprolactinaemia.

Abortion, Induced↗
PubMed1991

[Relation between changes in compound action potential tuning curves and the pathology of cochlear hair cells stereocilia].

Relations of the changes of compound action potential tuning curve (AP-TC) and AP(N1) threshold to the pathology of the cochlear hair cells stereocilia were examined in acoustic-traumatized guinea pigs. The results showed that all animals with hair cell stereocilia damaged showed deteriorations of AP-TC. It supports the suggestion that mechanical properties of hair cell stereocilia contribute to the frequency selectivity of cochlea. After exposure, the characteristic frequency (CF) shift of AP-TC was observed. The mechanism of CF shift may be related to the lesion of hair cell stereocilia which may change normal tono-topic on cochlear level. Correlation between the damages of inner/outer hair cell stereocilia and changes of AP-TC and AP threshold suggested that the threshold and tuning properties of the cochlea are dependent upon the integrity of the inner and outer hair cells and their inter-relationship.

Action Potentials↗
PubMed1990

[Establishment of Wg3h-neo cell line with two genetic markers].

Plasmid PSV2-neo DNA containing neo gene (PSV2 neo) was successfully transferred into Wg3h cells, a HGPRT-Chinese hamster fibroblast cell line, by calcium phosphate DNA co-precipitating technique. Cells carrying two selectable markers (AGR and G418R) were thus obtained and passed for more than 40 generations, and designated as Wg3h-neo cell line. The existence of PSV2-neo sequences in the Wg3h-neo genome was confirmed by dot-blot hybridization with PSV2-neo DNA probe. Comparative studies showed that no significant difference in morphology, growth rate or genetic characteristics could be found between the Wg3h and Wg3h-neo cell lines.

Animals↗
PubMed1989

[Protective effects of the pollen of Codonopsis pilosula (Franch.) Nannf. on liver lesions at the ultrastructural level].

The experimental hepatic lesion of C57 mice was induced by carbon tetrachloride (CCI4), and the feeds containing pollen of Codonopsis pilosula were given to the animals. It was found by electronic microscopy that these pollens evidently reduced the hepatic steatosis, improved liver necrosis, suppressed the formation of the collagen fibrils in Disse's spaces and around central veinules. It was shown that the pollens of Codonopsis pilosula could counteract efficiently the liver lesion of mice induced by CCI4.

Animals↗
PubMed1989

[Correlation of changes in compound action potential (CAP) tuning curves and cochlear lesion in guinea pigs after explosion].

The purpose of the present study was to investigate the sensitivity of compound action potential (CAP) tuning curves to changes of the cochlear status in guinea pigs after explosion and their ability to reflect specific histological variations. The results were as follows: 1. The CAP tuning curves were abnormally broad and the Q 10 dB values were reduced by a factor of 1 after explosion, indicating wider tuning. 2. The degree of broadening of the CAP tuning curves seemed to increase as the hair cell loss increased. 3. After explosion, the tip of the tuning curve shifted to frequencies significantly higher or lower than that of the signal, it might be related to the location of hair cell loss in the cochlea. 4. In animals for which damage was restricted to only three rows of outer hair cells, changes of the CAP tuning curves were observed. It provides further evidence that the tuning properties of cochlear nerve fibers are dependent upon the integrity of the outer hair cells even though the great majority of fibers innervate inner hair cells only.

Animals↗
PubMed1987

Management of fibrin pupillary-block glaucoma after pars plana vitrectomy with intravitreal gas injection.

After pars plana vitrectomy and fluid-gas exchange, two patients developed fibrin membranes across the pupillary space resulting in pupillary block and subsequent glaucoma. In one case the angle was closed; in the second case the angle was open because of gas in the anterior chamber. In both cases the argon laser made permanent openings in the fibrin pupillary membrane that relieved the pupillary block.

Adult↗