The manner in which the cycle of the germinal epithelium is affected during progressive atrophy of seminiferous tubules, and the form of cellular degeneration that occurs at each stage of the cycle has been studied in adult rat and mouse testis following unilateral ligation of the vasa efferentia. Following the ligation, which was placed as close to the testis as possible, groups of animals were killed at postoperative periods ranging from 1 to 10 days for rats, and 16 hours to 7 days for mice. The stages of the cycle were identified by the periodic acid-Schiff-haematoxylin technique using the classification of Leblond and Clermont (1952) and Oakberg (1956a). The timing of the cycle did not appear to be disrupted by the degenerative changes that resulted: at all postoperative periods, the viable germ cells were associated with the same stages of the cycle as they are in the normal testis. The frequency with which each stage of the cycle occurred was measured in the ligated testis of the mouse and found to be unchanged from that established in the control testis. The atrophic reactions at each stage of the cycle followed a consistent and well-defined sequence of events which have been described in the form of a general scheme. The proposed scheme has not previously been described in the literature, and consists of 4 main steps in tubule degeneration. During stages I - IX of the cycle these steps are: (1) the "spermatid sloughing" stage, (2) the "multinucleated body" stage, (3) the "Sertoli cell cytoplasm" stage, and (4) the "Sertoli cell sloughing" stage. During stages X - XII of the cycle in the mouse (stages X - XIV in the rat), the first 2 of the 4 degenerative steps differ and have been termed: (1) the "cellular sloughing" stage, and (2) the "spermatocyte ghost cell" stage. Degeneration of seminiferous tubules affected Sertoli cells in a definite manner: the Sertoli cell nuclei increased in number, frequently migrated away from the basement membrane and were often sloughed into the tubule lumen. These changes in the behaviour of Sertoli cells during tubular atrophy are discussed. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Hong Kong, 1994. / Includes bibliographical references (leaves 257-287).

Thesis (doctoral)--Göttingen, 1934. / Includes bibliographical references (p. 17-190).

Thesis (doctoral)--Göttingen, 1934. / Includes bibliographical references (p. 17-190).

published_or_final_version / Biochemistry / Doctoral / Doctor of Philosophy

by Ka-bik Lai. / Thesis (M.Phil.)--Chinese University of Hong Kong, / Includes bibliographical references (leaves 59-67). / Chapter Chapter I --- Introduction / Chapter I.1 --- Anatomy and functions of the epididym --- p.is / Chapter I.1.1 --- Gross anatomy and functions --- p.1 / Chapter I.1.2 --- Histology of the epithelium and functions of different cell types --- p.3 / Chapter I.2 --- Regional difference / Chapter I.2.1 --- Epithelium --- p.4 / Chapter I.2.2 --- Electrolyte transport --- p.6 / Chapter I.3 --- Short circuit current studies on C1- secretion in the cultured rat epididymal epithelium --- p.7 / Chapter I.4 --- Physiological effects of vasopressin in the epididymis and the male reproductive tract --- p.10 / Chapter I.5 --- Objectives of the study --- p.14 / Chapter Chapter II --- Materials and methods / Chapter II. 1 --- Materials / Chapter II.1.1 --- Chemicals for cell culture --- p.16 / Chapter II. 1.2 --- Chemicals and drugs for short circuit current study --- p.16 / Chapter II. 1.3 --- Materials for preparing pervious supports --- p.16 / Chapter II.2 --- Preparation of solution for short circuit current study --- p.17 / Chapter II.3 --- Preparation of pervious supports for the cultured epithelium --- p.17 / Chapter II.4 --- Culture of rat epididymal epithelial cells / Chapter II.4.1 --- "Dissection of the efferent duct, the initial segment and the cauda epididymidis" --- p.17 / Chapter II.4.2 --- Culture procedures for the epithelium --- p.19 / Chapter II.4.3 --- Confluent epithelial monolayer --- p.22 / Chapter II.5 --- Short circuit current measurement / Chapter II.5.1 --- Mounting of cultured epithelium on Ussing chambers --- p.22 / Chapter II.5.2 --- Experimental setup for zero voltage clamp --- p.25 / Chapter Chapter III --- Results / Chapter III.1 --- Regional differences / Chapter III.1.1 --- Basal bioelectrical properties --- p.29 / Chapter III. 1.2 --- Effects of C1- replacement and C1- channel blocker --- p.29 / Chapter III.1.3 --- Effects of ion transportor inhibitors --- p.33 / Chapter III. 1.4 --- Effect of adenylate cyclase stimulator --- p.33 / Chapter III.1.5 --- Effect of exogenous PGE2 --- p.33 / Chapter III.1.6 --- Effect of Ca2+ ionophore --- p.36 / Chapter III.2 --- Effect of [arg8]-vasopressin / Chapter III.2.1 --- Effect of [arg8] -vasopressin on short circuit current --- p.36 / Chapter III.2.2 --- Effects of C1- replacement and C1- channel blocker --- p.40 / Chapter III.2.3 --- Effect of repeated stimulation with [arg8]- vasopressin --- p.40 / Chapter III.2.4 --- Effects of receptor antagonists --- p.40 / Chapter III.2.5 --- Effects of thapsigargin and trifluoperazine --- p.44 / Chapter III.2.6 --- Effects of indomethacin --- p.44 / Chapter III.2.7 --- Effects of forskolin --- p.47 / Chapter Chapter IV --- Discussion --- p.50 / Chapter Chapter V --- References --- p.59

These experiments were designed to test the suitability of dextrans as alternate light and electron microscopic tracers to horseradish peroxidase (HRP) in studies of respiratory epithelial permeability in control and cigarette smoke-exposed guinea pigs. Nine animals were utilized initially to establish the most effective means of preserving highly water-soluble dextran while adequately maintaining airway cell ultrastructure. The perfusion-nebulization fixation and carbohydrate retention techniques developed were then used on the twenty-six guinea pigs in the permeability study. Five animals served as controls, while others were exposed to the dextran tracer, smoke from 10 cigarettes, or both. Intratracheal tracer instillations of sonicated preparations of unlabelled or either FITC- or iron-labelled dextran T10 or T40 were carried out 1/2-hour after smoke exposure. All dextrans could be visualized light-microscopically along the respiratory epithelium of airways and lung parenchyma by the Mowry-Millican technique, a modified alcoholic periodic acid-schiff (PAS) stain. As witnessed in previous HRP studies, some post-mortem tracer diffusion was seen, and no difference in dextran epithelial penetration was noted between smoked and sham-smoked animals. At the electron microscopic level, treatment of guinea pig trachea and lung with aldehyde-OsO₄-lead citrate fixative cocktail preserved the unlabelled dextran as irregular, highly electron-dense aggregates of particles along the luminal surfaces only of airways of control guinea pigs. One-half of the animals in the smoke-exposed group showed penetration of dextran between the tracheal epithelial cells. Incomplete tracer dissolution prior to instillation, as shown by negative staining of the instillates, is thought to be responsible for this inconsistency. No intrapulmonary or alveolar trans-epithelial tracer transport could be detected. FITC-dextrans presented the additional advantages of qualitative detection by fluorescence-differentiated interference contrast (DIC) microscopy and quantitative detection by spectrophotofluoro-metric means. Iron-dextrans exhibited too large a molecular size for practical use with smoke-exposed guinea pig tracheobronchial epithelium. We conclude that dextrans provide distinct advantages over HRP in terms of low price, inertness, and size versatility, as light and electron microscopic tracers. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Thesis (M.S.)--University of Michigan, 1968.

Thesis (M.S.)--University of Michigan, 1974.