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Biomedical subjects

M Oh

Publications and source records attributed to M Oh.

31 records · Page 2Linked to original sources
PubMed1980

Melanin-containing cells in the uterine cervix: histochemical and electron-microscopic studies of two cases.

Previously unreported histochemical and electron-microscopic features of the melanin-containing cells of the endocervix are described. Histochemical and ultrastructural stud es of the endocervices of two women confirmed that the brown pigment in the cervical myometrium was melanin. No such pigment was found in the endocervical epithelium. The possible origin of these melanin-containing cells is also discussed. This is believed to be the first report on the histochemical and electron-microscopic confirmation of these endocervical melanin pigments.

Adult↗
PubMed1979

An electron microscopic study on the lining mucosa of developing rat vocal cords.

To explain the developmental process of epithelial cells of true vocal cords, larynges obtained from 42 fetal and 36 developing young rats were examined using scanning and transmission electron microscopies. Although the membranous portion was indistinguishable from the arytenoid portion in the prenatal stage, there was no squamous cell epithelium on the glottis. The lining epithelium of vocal cords in 15, 16, and 17 day fetal rats was composed of cuboidal and columnar cells which had a primary cilium. Immediately after birth the membranous portion of vocal cords became recognizable, and ciliated cells present on vocal cords retrogressed rapidly while nonciliated squamous cells grew and extended. Results of the present study show that epithelial cells of ciliated columnar type covering vocal cords change remarkably to nonciliated squamous cells between prenatal and postnatal stages.

Animals↗
PubMedDate not supplied

Scrub typhus pneumonitis acquired through the respiratory tract in a laboratory worker.

We report a case of scrub typhus pneumonitis in a laboratory worker who apparently acquired it through the respiratory tract. The patient was suffering from fever, cough and dyspnea. He had both cervical and axillary lymphadenopathy, and hepatomegaly. A chest X-ray showed interstitial infiltrates. A diagnosis of scrub typhus was established upon isolation of Orientia tsutsugamushi. 12 days before the patient showed symptoms, he had purified O. tsutsugamushi proteins from infected cells using an ultrasonication method which could generate aerosols containing O. tsutsugamushi.

Adult↗
PubMedDate not supplied

Arsenic exposure, smoking, and respiratory cancer in copper smelter workers.

A report by Lee and Fraumeni in 1969 linked exposure to arsenic and other contaminants to a threefold excess of respiratory cancer among 8,047 employees at the Anaconda copper smelter. We established vital status through December 1977 for a sample of 1,800 men from the original cohort. Average arsenic concentrations were estimated for each smelter department based on industrial hygiene measurements made from 1943 to 1965. Departments with similar concentrations were combined into four categories of exposure: 1) low (less than 100 micrograms/m3), 2) medium (100-499 micrograms/m3), 3) high (500-4,999 micrograms/m3) and 4) very high (greater than or equal to 5,000 micrograms/m3). Three indices of individual arsenic exposure were developed: time-weighted average, 30-day ceiling, and cumulative. Exposures to sulfur dioxide and asbestos were also examined. Smoking habits were obtained by questionnaire. Mortality was compared to that of men in the State of Montana using the modified lifetable method. A clear dose-response relationship between arsenic exposure and respiratory cancer was demonstrated. Men in the highest exposure category had a sevenfold excess. Those in the low and medium categories had a risk close to that expected. Ceiling arsenic exposure appeared to be more important than did time-weighted average exposure. Sulfur dioxide and asbestos did not appear to be important in the excess of respiratory cancer, although sulfur dioxide and arsenic exposures could not be separated completely. Smoking did not appear to be as important as arsenic exposure. Our findings suggest that had men worked only in departments with low or medium arsenic exposures (i.e., less than 500 micrograms/m3) there would have been little excess respiratory cancer. Since the estimates of arsenic exposure were based on department averages rather than on concentrations for individual jobs, these results must be interpreted with caution.

Aged↗
PubMedDate not supplied

Fine structures of the normal mucosa in developing rat middle ear.

Forty-two fetal and 90 developing young rats were studied electron microscopically to obtain a normal cellular distribution pattern of middle ear mucosa. The results showed that while ciliated columnar or cuboidal cells interspersed with secretory cells were predominantly distributed around the tympanic orifice and transitional zone, cuboidal or squamous nonciliated cells without secretory granules were numerous in the remaining part of the bulla. Development of ciliated cells started at the 17th or 18 th fetal day,paralleling that of secretory cells. The number of ciliated and secretory cells increased rapidly after birth. Glands were not found in the osseous tube, tympanic orifice, or other portions of the middle ear cavity in fetal, newborn, or suckling rats, while they are abundant in the cartilaginous portion of the tube. The findings of this study indicate that both secretory and ciliated cells are normal components of middle ear mucosa although these cells are restricted to the tympanic orifice and transitional zone, and that the mucociliary defense system starts to develop during the fetal stage.

Animals↗
PubMedDate not supplied

A prosodic analysis of three types of Wh-phrases in Korean.

Wh-phrases in Korean are ambiguous due to the lexical ambiguity of "wh" words: wh-pronouns as in a wh-question, or indefinite pronouns as in a yes/no-question. Furthermore, since a wh-word in Korean is in-situ (i.e. not moved to the front of a sentence as in English), wh-questions are not distinguished from echo questions in their surface forms. In this paper, we investigated prosodic characteristics disambiguating these three types of wh-phrases: 1) wh-question, 2) yes/no-question, and 3) incredulity question, a kind of echo question giving an incredulity meaning. Production and perception data were examined to discover what prosodic features are used to distinguish these three types of wh-phrases and which feature is more salient and reliable in perceiving such differences. The production results show that yes/no-questions and other types of questions are distinguished by different accentual phrasing, while incredulity and wh-questions are distinguished by different peak amplitudes, pitch ranges, and boundary tones. Interestingly, not all speakers used the same strategy to distinguish incredulity from wh-questions. The results of the perception test suggest that accentual phrasing is significantly related to the perception of three types while amplitude and boundary tones are significantly related to the perception of wh- and incredulity questions, respectively.

Female↗
PubMedDate not supplied

Microcrypt extensions of tonsillar crypts.

The crypts of human palatine tonsils were examined electron microscopically. The cryptal epithelia contained three types of micropores (termed microcrypt). Type I microcrypts opened between intercellular spaced of the epithelial cells. Free cells were observed in the micropores. Type II microcrypts opened near the center of a cryptal epithelial cell. Type III microcrypts appeared after "specialized epithelial cells" degenerated and fell off. Many mature plasma cells are attached to the walls of the sinusoidal vessels in the lower boundary zone of the epithelium and subepithelial layer. Lymphocytes were observed migrating from the postcapillary venules of the subepithelial zone. The findings indicate that the microcrypts are probably orifices for tunnel-like passages of free cells and that they are located in the walls of the tonsillar crypts. The lymphocytes in the passages perhaps come from lymphoid tissues in the subepithelial layer and postcapillary venules, and the antibodies produced in the cryptal epithelia of the palatine tonsils may contribute to humoral immunity.

Adolescent↗