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Biomedical subjects

M C Chang

Publications and source records attributed to M C Chang.

404 records · Page 23Linked to original sources
PubMedDate not supplied

The meaning of sperm capacitation. A historical perspective.

It should be recalled that sperm capacitation was originally defined in 1952 as some physiological changes of the spermatozoa in the female genital tract before they are capable of penetrating and fertilizing the eggs. It was found further that capacitation can be achieved outside the female tract, first in the presence of biological fluids, and then in the absence of biological fluids. Later on it was found that capacitated rabbit uterine spermatozoa still have acrosome and that the acrosome reaction of rabbit spermatozoa occurred in contact with eggs in the oviduct. Thus, several authors separated acrosome reaction from capacitation and considered capacitation as a preparation for the acrosome reaction, even though the titles of their articles still implied that capacitation included acrosome reaction. During the past 30 years we have found many membrane changes on the molecular and immunological level in spermatozoa that prepare them for physiological changes such as "hyperactivation," and morphological changes such as "the acrosome reaction." These events lead to more vigorous motility and to the release of various enzymes for the penetration of the egg. Undoubtedly, further study will reveal more molecular, physiological, and morphological changes in the mammalian spermatozoa before they are capable of fertilization. There are definite changes before hyperactivation and acrosome reaction, but these changes are parts of capacitation, if we prefer to keep its original meaning. It is proposed here that in order to save further confusion, capacitation of spermatozoa should be defined as originally proposed, that is, to include all the events that lead to the development of the capacity of mammalian spermatozoa to penetrate eggs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
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Percutaneous transcatheter treatment of an intracavitary aspergilloma.

We describe a case of massive hemoptysis, secondary to an intracavitary aspergilloma, successfully treated by computed tomography (CT)-guided placement of a Cope-loop catheter with daily transcatheter instillation of amphotericin B and cavitary irrigation. Over a 15-day period, this regimen resulted in cessation of hemoptysis and radiographic resolution of the aspergilloma. No complications were encountered. A follow-up CT of the thorax showed no recurrence of the aspergilloma at 3 months.

Adult↗
PubMedDate not supplied

Effects of chronic beta-amyloid treatment on fatty acid incorporation into rat brain.

The present study evaluated the effects of chronic A beta administration on radio-labeled plasma fatty acid incorporation in rat brain. A beta was chronically infused intraventricularly via an osmotic minipump, for 1 week, at a concentration of 460 microM. After the infusion, fatty acid incorporation was quantified using an in vivo method developed in this laboratory. Three radiolabeled fatty acids were separately infused IV in awake animals. Biochemical analyses of fatty acid incorporation and histology for A beta showed no differences between control (vehicle infusion only) and experimental groups. However, in vitro tests on the cytotoxicity of A beta showed that it caused significant cell death relative to controls (PC-12 cells). The lack of effect of infused A beta on radiolabeled fatty acid incorporation is discussed.

Amyloid beta-Peptides↗
PubMedDate not supplied

Detection of human papillomavirus types in cervical lesions of patients from Taiwan by the polymerase chain reaction.

BACKGROUND AND OBJECTIVES: The association of human papillomavirus (HPV) infection with cervical carcinoma is well documented. The HPV types in cervical lesions of patients from Taiwan are analyzed by the polymerase chain reaction (PCR). STUDY DESIGN: DNA was extracted from paraffin-embedded, formalin-fixed tissues using a sonication method. PCR was performed using type-specific primers for the presence of HPV types 6, 11, 16, 18, 31, and 33 DNA. Amplified product was subjected to gel electrophoresis and Southern blot hybridization analysis. RESULTS: A total of 129 cervical lesions and normal cervical biopsies were examined. Histologic examination revealed a spectrum of lesions, which were classified as condyloma acuminata (AC), condyloma (CL), koilocytosis (KL), various grades of cervical intraepithelial neoplasia (CIN I, II, and III), carcinoma in situ (CIS), and invasive carcinoma (ICa). Of 114 cervical lesions, 65% (26 of 40) of AC; 61% (11 of 18) of CL; 20% (2 of 10) of KL; 25% (1 of 4) of CIN I; 69% (9 of 13) of CIN II; 80% (12 of 15) of CIN III; 83% (5 of 6) of CIS; and 100% (8 of 8) of ICa were positive for at least one type of HPV by the PCR. Among the 74 HPV-positive specimens, 19 (26%) were detected with multiple types. HPV DNA was detected in the cervical biopsies of 1 of 15 (6.7%) normal individuals. CONCLUSION: Excluding AC, HPV 6 and/or 11 (HPV 6/11), HPV 16 and/or 18 (HPV 16/18), and HPV 31 and/or 33 (HPV 31/33) were detected in 40% (19 of 48), 71% (34 of 48), and 12% (6 of 48) of neoplastic lesions of patients from Taiwan respectively. These findings are compatible with those reported by others worldwide.

Base Sequence↗
PubMedDate not supplied

Helicobacter pylori stool antigen (HpSA) test--a simple, accurate and non-invasive test for detection of Helicobacter pylori infection.

BACKGROUND/AIMS: To access the reliability of a newly developed test, the Helicobacter pylori (H. pylori) stool antigen (HpSA) test was used for detection of H. pylori infection. METHODOLOGY: Stool specimens were collected from 33 consecutive patients (19 males and 14 females, age range: 16-73 years, mean: 49 years) who received upper gastrointestinal endoscopic examination for gastrointestinal symptoms. The H. pylori status was evaluated based on six different tests: culture, histology, biopsy urease test, 13C-urea breath test (13C-UBT), serology, and HpSA test. A commercial kit using an enzyme-linked immunosorbent assay examined HpSA in the stool. H. pylori status was defined as positive when the culture was positive or concordance of three of the other four tests (histology, biopsy urease test, 13C-UBT, and serology) was positive. RESULTS: Twenty patients were diagnosed as H. pylori-positive. The HpSA test was positive in 19 patients and negative in 14 patients. The sensitivity and specificity were 95.0% and 100%, respectively. The overall accuracy rate was 96.3%. CONCLUSIONS: The HpSA test is a new, simple, non-invasive method for accurate diagnosis of H. pylori infection.

Adolescent↗
PubMedDate not supplied

Implications for adolescent sex education in Taiwan.

This first Taiwan-wide sample survey of adolescent sexual awareness, knowledge, attitude, and behavior shows that secondary school students there: lack basic knowledge about contraception and reproduction, are often not being taught adequately about these subjects in school, have fairly permissive attitudes about sexual relationships, particularly males, are sexually active, particularly males and those in the private vocational high schools (although less so than their US counterparts), want to learn more about the nature of intimate relationships between males and females, and look to school and public health agencies to be more active sources of information and education.

Adolescent↗
PubMedDate not supplied

Taiwan's transition from high fertility to below-replacement levels.

This article compares the fertility experience of Taiwanese in the eight years since the total fertility rate reached 2.1 with that before fertility reached replacement levels. During the earlier period, two-thirds of the fertility decline resulted from falling marital fertility and one-third from higher age at marriage. The changing age distribution retarded this decline. Since 1983, the further decline to 1.7-1.8 has been entirely the result of the trend toward later marriage. Older age distributions now facilitate the decline. Births postponed by those marrying later make the conventional TFR misleading. Computation based on parity-progression ratios raise TFRs from 1.7 to 2.0, a number less alarming to policymakers. Contraceptive prevalence is at saturation levels in all major populations strata. The "KAP-GAP" has disappeared. What would have happened without Taiwan's effective family planning program is impossible to determine, but clearly, contraceptive services supplied by the program were the major proximate cause of Taiwan's fertility decline.

Adolescent↗