Glutathione S-transferases (GSTS), a family of isozymes that catalyzes the conjugation of glutathione to a variety of electrophiles, protect cellular constituents from electrophilic and oxidative attack. Aging is associated with an overall increase in oxidative stress and thus free radical production. The present study examines the immunocytochemical localization of Ya, Yc, Yb1, Yb2, Yo, and Yf GST subunits in the testis and epididymis of Brown Norway rats aged 3, 12, 18, and 24 months. In the testis, neither Sertoli nor germ cells showed changes in GST staining pattern during aging. At 24 months, two types of Leydig cells were noted. Some (peritubular) formed a distinct band at the periphery of the tubule while others were seen in the interstitial space. The peritubular cells were identified as Leydig calls by specific staining for 3beta-hydroxysteroid dehydrogenase (3beta-HSD), a Leydig cell specific marker. Both types of Leydig cells were intensely reactive for all GST subunits at all ages. In the epididymis, principal cells of all epididymal regions, except the proximal cauda region, showed no changes in GST expression at all ages examined. At 24 months, some principal cells of this region became greatly enlarged and vacuolated. These cells were unreactive for Yo, Yb1, Yb2 and Yc, while adjacent normally appearing principal cells maintained the same intensity of expression as seen in 3 month controls. In contrast, vacuolated principal cells were reactive for the Ya subunit, while adjacent normal principal cells were unreactive. These data indicate that selective changes occur in the expression of GM at 24 months in principal cells having both a normal and a vacuolated appearance. Taken together, these data show that aging affects region-specific changes in GST expression in the epididymis and Leydig cell distribution in the testis. (Abstract shortened by UMI.)

Prosaposin is a glycoprotein that exists in two forms: a 65-kDa isoform which is found in lysosomes and a 70-kDa form which is secreted to the extracellular space. In the lysosome, prosaposin is proteolytically cleaved into four polypeptides named saposin A, B, C and D. Each of these subunits mediates the breakdown of glycosphingolipids in conjunction with specific hydrolases present in the lysosome. The absence of either a saposin or the specific hydrolase is the cause of a number of lysosomal storage diseases, such as a variant form of Gaucher's disease and metachromatic leukodystrophy. Although the 65-kDa isomer is found in lysosomes, the precise site of entry of this protein along these acidic compartments is not known. Therefore, the first objective of this study was to find out whether prosaposin enters into the lysosome, endosome, or both. The second objective of this study was to determine whether lysosomotropic agents, such as ammonium chloride (NH4Cl) and leupeptin, affect the concentration of prosaposin in the endosomal/lysosomal pathway. (Abstract shortened by UMI.)

Recently smooth-muscle tissue has been observed in the annular ligament of the moustached bat, Pteronotus parnellii. In order to lead to improved understanding of the function of this highly developed smooth-muscle system surrounding the tympanic membrane, a finite-element model was developed. / The complex geometry of the middle ear was defined using both magnetic-resonance microscopy and histological data. Contributions were made to the locally written software which was used for image segmentation and finite-element mesh generation. / The action of the smooth-muscle fibres is modelled by applying a radial load to the model of the tympanic membrane. The radial load is represented by placing load vectors tangential to the model of the tympanic membrane. / Simulations were carried out in order to investigate convergence, sensitivity to tympanic-membrane shape, and to evaluate the effects of pressure and radial loads.

Previous studies of the human stretch reflex have been limited by difficulties separating the reflex response from those due to passive and intrinsic joint properties. This study has presented and experimentally verified a method for separately determining these contributions to the human ankle response, and used this technique to assess the reflex contribution to joint dynamics during the application of a stochastic position perturbation. Although this method was applied to the human ankle, it is readily applicable to any intact joint. / The results of this analysis showed that most of the neuromuscular response could be accounted for by two parallel pathways: one for the stretch reflex dynamics, and another for the intrinsic joint stiffness. The estimated nonparametric model accounted for 92% of the measured torque variance between 0.5-25Hz, and greater than 94% of the variance between 5-12Hz, where the stretch reflex was found to be most effective.

The anterior-most elements of the vertebral column of Eusthenopteron foordi are examined by direct observation of articulated material. Large blade-like supraneural spines are present above neural arches 1, 3, and 5, but not 2 or 4. The supraneural spines support a muscular complex involved in feeding, not only through raising the snout, but also in depressing the lower jaws by the forward swing of the quadrate. The similarity in skulls of osteolepiforms, and between osteolepiforms and Paleozoic tetrapods implies that a cranio-vertebral joint of similar function existed in the ancestor of tetrapods, forming the precursor of the tetrapod atlas-axis complex. / The distinct nature of the basioccipital and exocippitals of tetrapods is the result of reduced ossification of the occiput, and no the incorporation of vertebral elements onto the back of the braincase relative to the rhipidistian condition. The similarity between the occiput and succeeding vertebrae of some primitive tetrapods is due to analogous ossification of notochordal tissue. Bony occipital condyles arose separately in many lineages of Paleozoic tetrapods. The atlas-axis complex of tetrapods is constrained by the pattern of occipital articulation. It is an excellent character for diagnosis of particular groups, but a poor character for determining relationships between separate lineages.

Sulfated glycoprotein-2 (SGP-2) has been shown to be secreted by the epididymal principal cells whereupon it binds to sperm where it is possibly involved in transporting lipids to or from their surface or providing them with a protective coat. However, SGP-2 also appear to be endocytosed by principal cells along the epididymis. Recently, it has been demonstrated that glycoprotein 330 (gp330), a low density lipoprotein receptor-related protein, can mediate the endocytosis of SGP-2 in the nonciliated cells of the efferent ducts and cultured cells (Kounnas et al., 1995; Morales et al., 1996). The purpose of the present study were in part to correlate the expression of SGP-2 with gp330 along the epididymis to determine if gp330 was essential for SGP-2 internalization. In addition, experiments were carried out to determine which factor(s) are involved in the regulation of expression of these two proteins. The epididymides were fixed by perfusion with Bouin's fixative and examined with anti-SGP-2 and anti-gp330 antibodies using light microscope immunocytochemistry. (Abstract shortened by UMI.)

Epididymides post-fixed in reduced osmium were used to study the morphological characteristics of the Golgi apparatus of principal cells of the initial segment. Others, fixed in glutaraldehyde, were treated to detect nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyro-phosphatase (TPPase), and cytidine mono-phosphatase (CMPase) activities within Golgi compartments and glucose-6-phosphatase activity localized in cisternae of ER. / The Golgi apparatus of these cells is composed of numerous saccular and tubular elements. On the cis face of the Golgi there is an osmiophilic tubular network. Of the numerous subjacent saccules, the first is dilated and unreactive for phosphatases, the next 3 show NADPase activity and the last 4 are TPPase positive. On the trans aspect of the stack there are 3 or 4 CMPase positive trans Golgi networks, one showing a peeling off configuration while the other 2 or 3 are completely separated from the stack. The TGN's often contain nodular distensions suggestive of secretion granule formation and occasionally present a shrivelled appearance. / Cisternae of ER showing buds are present on the cis face of the stacks.

Light (LM) and electron (EM) microscope immunocytochemistry were used to investigate the distribution of SGP-2 in the rete testis, efferent ducts and epididymis. Intense immunolabeling was observed in the apical and supranuclear regions of the epithelial cells lining the rete testis and efferent ducts which, under EM observation, corresponded to a labeling of the cell's endocytic apparatus. Sperm in the lumen of the efferent ducts were unreactive. The strongest immunolabeling was observed in the caput epididymidis, but demonstrated variable intensities of labeling from cell to cell. More detailed EM observation of labeled principal cells revealed gold particles over the cell's secretory apparatus. / Results suggest that testicular SGP-2 dissociates from sperm during passage through the rete testis and efferent ducts, where it is endocytosed by the epithelial cells lining these regions. Testicular SGP-2 is subsequently replaced by epididymal SGP-2, which is secreted by epididymal principal cells. Furthermore, the principal cells of the epididymis appear to be in different functional states with respect to the secretion of epididymal SGP-2 within a given region and in different regions of the duct.

Thesis (Ph.D.)--Indiana University, Dept. of Kinesiology, 2007. / Source: Dissertation Abstracts International, Volume: 68-07, Section: B, page: 4882. Adviser: John S. Raglin. Title from dissertation home page (viewed Apr. 21, 2008).

Thesis (Ph.D.)--Indiana University, Dept. of Anthropology, 2007. / Source: Dissertation Abstracts International, Volume: 68-09, Section: A, page: 3930. Adviser: Kevin D. Hunt. Title from dissertation home page (viewed May 8, 2008).