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Sex steroids in intersexual fishes (1989)

Chan, S. T. H. ; Yeung, W. S. B.

Springer

Fish physiology and biochemistry 7 (1989), S. 229-235

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ISSN: 1573-5168

Keywords: Monopterus albus ; Rhabdosargus sarba ; sex reversal ; protogyny ; protandry ; steroidogenesis ; sex steroids

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract Studies of thein vitro gonadal steroidogenesis in intersexual fishes, using labelled testosterone as precursor, showed large species variation. The protogynousMonopterus albus produced predominantly 5α-reduced metabolites while the protandrousRhabdosargus sarba produced mainly 5β-reduced products. Both fishes synthesized 11-oxotestosterone; the synthesis of which appeared to mediate mainly through adrenosterone inM. albus butvia 11β-hydroxytestosterone inR. sarba. When the plasma levels of androstenedione, testosterone, 11-oxotestosterone, 11β-hydroxytestosterone, estrone and 17β-estradiol among the male, intersexual and female phase of the same species were compared, available data showed that either there was no obvious difference among the different sexual phases or the differences could be accounted for by the seasonal reproductive activities of the animal. Except for androstenedione, there are no marked changes in plasma testosterone, 11-oxotestosterone, 11β-hydroxytestosterone, estrone and 17β-estradiol levels in the intersexual phase compared with the female and male, it is unlikely that these classical sex steroids act as a primary trigger of natural sex reversal in these fishes; the role of androstenedione awaits further elucidation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00004711

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Enlargement of the ulnar nerve behind the medial epicondyle (1963)

Chang, K. S. F. ; Low, W. D. ; Chan, S. T. ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

The @Anatomical Record 145 (1963), S. 149-155

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ISSN: 0003-276X

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Medicine

Notes: Enlargement of the ulnar nerve behind the medial epicondyle was noticed in museum and demonstration specimens and also in the dissection room cadavers. An investigation was carried out to study the incidence and character of the enlargement entirely from fresh autopsy cases, which included 400 ulnar nerves from 200 autopsy cadavers of Chinese subjects of all ages. The enlargement was graded into three categories - slight, moderate, and marked. Histological sections, 40 μthick and stained with H. & E., were examined. Twenty nerves from ten adult bodies were tested under stress for extensibility along the length of the nerve. Fortynine per cent of the ulnar nerves and 60.5% of cadavers of the total sample showed this enlargement, the incidence being greater in males than in females and slightly greater in the right limb than the left limb. Slight and moderate enlargement occurred in all ages; marked enlargement occurred only in ages over 35. The enlargement presented a normal histological picture; the enlargement was due to an increase of connective tissue present. The experimental results of extensibility along the length of the nerve showed the retro-epicondylar region, whether enlarged or not, to be more extensible than the rest of the nerve. While there seemed to be a tendency of a decrease of extensibility with enlargement, the correlation between extensibility and enlargement was insignificant statistically.

Additional Material: 1 Ill.