Call number: LD2668 .T4 1961 K65

In addition all patients examined by means of using testicular angiography before the first of November 1978» have been included. 123 patients were intended for angiography, 13 of them bilaterally. The intention with the investigation was to determine whether selective angiography of the testicular artery might be a useful examination in cases of a non-palpable testis and in patients with different intrascrotal lesions. There is a description of a useful method of investigation. The normal angiographic anatomy of the testicular artery is also de­scribed, both retroperitoneally and in the scrotum. In cases with a non-palpable testis it is shown that it is easy to distinguish between agenesis and cryptorchism. The normal magnification angiography of the testis is shown and how various intrascrotal lesions alter the picture. Finally some cases with retroperitoneal lesions are presented in which the testicular artery is committed. / <p>Diss. Umeå : Umeå universitet, 1979, härtill 4 uppsatser</p> / digitalisering@umu

Infertility affects ~20% of couples in Europe and in 50% of cases the problem lies with the male. The development of assisted reproductive technologies (ART) such as in vitro fertilisation (IVF) and intra-cytoplasmic spermatozoa injection (ICSI) has allowed some couples to overcome male-factor infertility. However concerns remain over the increasing use of ART as elevated levels of DNA damage in sperm from infertile men have been reported and a link between DNA damage in sperm and early embryonic failure has been demonstrated. DNA damage in sperm, caused by oxidative stress may also be passed on from father to child resulting in an increased incidence of childhood cancer. This has led to fears that the use of damaged sperm in ART could contribute to early embryonic failure and/or birth defects. The studies described in this thesis used mouse models to investigate the relationship between DNA integrity in male germ cells and male fertility. This was achieved by studying both the effects of targeted ablation of genes involved in DNA repair and the impact of scrotal heat stress on testicular function and sperm DNA integrity. Three lines of transgenic mice with deletions in genes involved in genomic integrity (Ercc1, Msh2 and p53) were studied. All three genes are expressed in the testis. These studies confirmed and extended studies on Ercc1 knockout (-/-) mice showing reduced germ cell complement, increased apopotosis, an increased percentage of damaged sperm and demonstrated for the first time that depletion of Ercc1 results in an increased incidence of unrepaired double strand DNA breaks (DSB) in pachytene spermatocytes. The persistence of DSBs in spermatocytes and abnormal sperm chromatin structure confirmed that the repair functions of Ercc1 are essential for normal germ cell maturation. In the p53-/- mice these studies showed for the first time that there was an increase in DSBs in spermatocytes and an increase in numbers of sperm with damaged DNA. The level of apoptosis was also increased in the testes suggesting that caspase-3 mediated apoptosis is not entirely p53 dependent as been previously suggested. These studies demonstrated for the first time that targeted ablation of Msh2 compromises germ cell complement and as in the Ercc1-/- this resulted in gaps in the seminiferous epithelium consistent with clonal loss of germ cells. Consistent with a role for MSH2 in mismatch repair no DSBs were detected in spermatocytes from Msh2-/-. Testicular function is temperature dependant and due to their location in the scrotum testes are normally kept between 2ºC and 8ºC below core body temperature. In mice transient scrotal heat stress (30 minutes at 38°C, 40°C and 42°C) disrupted testicular function. Analysis of sperm and testis parameters revealed that stress at 38°C was sufficient to have subtle effects on epididymal function but the higher temperatures had additional consequences for testicular function which resulted in DNA damage in spermatocytes, germ cells loss and increased apoptosis. Further studies into the pathways of apoptosis demonstrated that the mitochondrial/intrinsic pathway plays a role in heat stress response. The fertility of males was altered in those heated to 42°C resulting in reduced pregnancy rate and litter size. Given that the paternal genome is reported to be required for the development of extraembryonic tissues and this will influence growth of the embryo, it was interesting to note an increase in resorption sites in pregnancies using 40°C males. IVF was used to demonstrate that embryos formed using sperm from males stressed at 42°C were compromised between the 4-cell and blastocyst stage suggesting that though sperm with DNA damage are still capable of fertilisation, the paternal DNA was introducing genomic instability to the embryo and having fatal effects on development. These studies have also shown that one possible underlying cause of the disturbance in testicular function is hypoxia, as a marked increase in Hif1 alpha (a marker of hypoxia) mRNA and relocalisation of the protein was observed in the testis. In conclusion, DNA damage in the male germ line caused either by induced stress, or by targeted ablation of DNA repair genes, can disrupt testicular architecture, function and therefore the fertility of mice. These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production and that increased scrotal temperature can cause subfertility in male mice. This study has provided further confirmation of possible male-mediated effects on embryo survival and these findings should be taken into consideration when using sperm from infertile men in IVF/ICSI treatments where the normal quality control processes involved in fertilisation are bypassed.

Sy Chun Choi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 123-160). / Abstracts in English and Chinese. / ABSTRACT --- p.i / 摘要 --- p.iv / ACKNOWLEDGEMENT --- p.vi / Chapter 1. --- Introduction / Chapter 1.1 --- General review of the testis --- p.1 / Chapter 1.1.1 --- Structure and function of the testis --- p.1 / Chapter 1.1.2 --- Testicular vasculature --- p.2 / Chapter 1.1.3 --- Testicular angiogenesis --- p.3 / Chapter 1.2 --- Vascular endothelial growth factor (VEGF) --- p.4 / Chapter 1.2.1 --- Discovery of VEGF --- p.4 / Chapter 1.2.2 --- Organization of VEGF --- p.4 / Chapter 1.2.3 --- Properties of the VEGF isoforms --- p.5 / Chapter 1.2.4 --- VEGF receptors --- p.6 / Chapter 1.2.5 --- Functions of VEGF --- p.8 / Chapter 1.3 --- VEGF in the testis --- p.10 / Chapter 1.3.1 --- Localization of VEGF and VEGF receptors in the testis --- p.10 / Chapter 1.3.2 --- Postulated functions of VEGF in the testis --- p.11 / Chapter 1.4 --- Regulation of VEGF --- p.11 / Chapter 1.4.1 --- "VEGF, hypoxia and the testis" --- p.11 / Chapter 1.4.2 --- "VEGF, nitric oxide and the testis" --- p.14 / Chapter 1.4.3 --- Cadmium-induced testicular toxicity --- p.16 / Chapter 1.4.4 --- "VEGF, glucocorticoids and the testis" --- p.17 / Chapter 1.4.5 --- Hormonal regulation of VEGF expression 226}0ؤimportance of LH --- p.19 / Chapter 1.4.6 --- VEGF and Leydig cell - macrophage interaction --- p.21 / Chapter 1.5 --- Aims of the present study --- p.24 / Chapter 2. --- Materials and methods / Chapter 2.1 --- Animals --- p.26 / Chapter 2.1.1 --- Spermatic cord torsion --- p.26 / Chapter 2.1.2 --- Cadmium chloride treatment --- p.27 / Chapter 2.1.3 --- Leydig cell depletion and cadmium chloride treatment --- p.28 / Chapter 2.1.4 --- Dexamethasone pretreatment and cadmium chloride injection --- p.28 / Chapter 2.1.5 --- hCG injection --- p.29 / Chapter 2.2 --- Immunohistochemistry --- p.29 / Chapter 2.2.1 --- Perfusion fixation of the testes --- p.29 / Chapter 2.2.2 --- Processing of the testes for histological section --- p.29 / Chapter 2.2.3 --- Immunohistochemical staining for VEGF --- p.30 / Chapter 2.2.4 --- Photomicrograph --- p.32 / Chapter 2.3 --- Cell cultures --- p.32 / Chapter 2.3.1 --- Cell lines of mouse TM3 Leydig cells and TM4 Sertoli cells --- p.32 / Chapter 2.3.2 --- Tumour cell line of mouse MLTC-1 Leydig cells --- p.33 / Chapter 2.4 --- Cell treatments --- p.33 / Chapter 2.4.1 --- Hypoxic treatment --- p.34 / Chapter 2.4.2 --- Cadmium chloride treatment --- p.36 / Chapter 2.4.3 --- hCG treatment --- p.37 / Chapter 2.4.4 --- Activators of second messenger systems --- p.37 / Chapter 2.4.5 --- Effect of pro-inflammatory cytokines and angiogenic growth factors --- p.38 / Chapter 2.5 --- Preparation of cDNA probes --- p.39 / Chapter 2.5.1 --- VEGF cDNA probe preparation --- p.39 / Chapter 2.5.2 --- P-actin cDNA probe preparation --- p.42 / Chapter 2.5.3 --- Purification of PCR products --- p.44 / Chapter 2.5.4 --- Confirmation of PCR products --- p.45 / Chapter 2.5.5 --- cDNA probe labeling --- p.46 / Chapter 2.6 --- RNA extraction --- p.46 / Chapter 2.6.1 --- Extraction of total RNA from testicular cell lines --- p.46 / Chapter 2.6.2 --- Extraction total RNA from testicular tissues --- p.50 / Chapter 2.7 --- Northern blot analysis --- p.51 / Chapter 2.7.1 --- Measurement of total RNA concentration --- p.51 / Chapter 2.7.2 --- RNA gel electrophoresis --- p.52 / Chapter 2.7.3 --- Transfer of RNA to membrane --- p.53 / Chapter 2.7.4 --- Hybridization with [α-32P]dCTP-labelled probes --- p.53 / Chapter 2.7.5 --- Autoradiography and densitometric quantification --- p.54 / Chapter 2.8 --- Data and statistical analysis --- p.55 / Chapter 3. --- Results / Chapter 3.1 --- Effects of hypoxia and cobalt chloride treatment on VEGF expression in TM3 and TM4 cells --- p.57 / Chapter 3.2 --- Effects of testicular torsion on VEGF expression in adult rat testes --- p.61 / Chapter 3.3 --- Antagonism of hypoxic induction of VEGF expression in TM3 cells by nitric oxide --- p.66 / Chapter 3.4 --- Effect of cadmium on VEGF expression in TM3 and TM4 cells --- p.66 / Chapter 3.5 --- Effect of dexamethasone on Cd-induced increase in VEGF expression in TM3 cells --- p.73 / Chapter 3.6 --- Effect of cadmium treatment on VEGF expression in the adult rat testes --- p.73 / Chapter 3.7 --- Effect of Leydig cell depletion on basal and Cd-induced expression of VEGF in adult rat testes --- p.76 / Chapter 3.8 --- Effect of dexamethasone on basal and Cd-induced expression of VEGF in adult rat testes --- p.76 / Chapter 3.9 --- "Effects of hCG,forskolin and phorbol ester on VEGF expression in TM3 and TM4 cells" --- p.79 / Chapter 3.10 --- Effect of hCG on VEGF expression in MLTC-1 cells --- p.92 / Chapter 3.11 --- "Effect of EL-lα, IL-1β, IL-6, TNF- α and TNF- β on VEGF expression in TM3 cells" --- p.92 / Chapter 3.12 --- Effect of bFGF and TGF- β1 on VEGF expression in TM3 cells --- p.102 / Chapter 4. --- Discussion / Chapter 4.1 --- Upregulation of VEGF expression in TM3 and TM4 cells by hypoxia and cobalt chloride --- p.108 / Chapter 4.2 --- Effect of testicular torsion on VEGF expression in adult rat testes --- p.110 / Chapter 4.3 --- Antagonism of hypoxic induction of VEGF expression in TM3 cells by nitric oxide --- p.111 / Chapter 4.4 --- "Effect of cadmium on VEGF mRNA levels in TM3 and TM4 cells, and in adult rat testes" --- p.113 / Chapter 4.5 --- "Effect of hCG,forskolin and phorbol ester on VEGF expression in TM3 and TM4 cells" --- p.116 / Chapter 4.6 --- Effect of cytokines and growth factors on VEGF expression in TM3 cells --- p.119 / Chapter 5. --- References --- p.123

Cancer is a highly complex disease that evolved in response to a wide range of biological and molecular changes that impact disease behaviour, treatment efficacy and clinical outcomes. Studying this diversity in human tumours is essential for gaining insights that will ultimately improve the survival rates of cancer patients. Cancer stem-like cells (CSCs) are believed to be responsible for invasive and metastatic features in tumours and can contribute to chemotherapy resistance and subsequent tumour relapses. There is an increasing need to identify the molecular mechanisms involved in tumour cells, particularly in CSCs. Cancer testis antigens (CTAs) are a subclass of germline proteins normally produced in immune-privileged sites, such as the testis, ovary and placenta of somatic tissues, and the presence of these antigens is increased in a variety of cancers. These characteristics make CTAs highly important immunotherapeutic targets, since they do not harness the immune response in the testes but encode immunogenic proteins that can induce a specific response in cancerous tissues. CTA genes are potentially very importance in clinical applications, including cancer diagnosis, vaccination and immunotherapy. This current study focused on the investigation of two CTAs, TDRD12 and LKAAEAR1, that may have an enhanced presence in cancer and the potential to be immunogenic. TDRD12 is linked to stemness features and enables the proliferation of germ line tumour cells. It appears to act as a possible transcriptional regulator for germline factors that are essential to cell cycle proliferation, germ cell maintenance and stem marker expression. TDRD12 may have the potential to drive oncogenesis and CSC targets. LKAAEAR1 was validated as a CTA at the protein level, showing its production was restricted to germ cells and the central nervous system from normal tissues and showed aberrant production in a wide range of tumours. This protein has been shown to be produced in germ cells undergoing spermatogenesis with strong nuclei staining, suggesting its potential role in this process. LKAAEAR1 potentially acts as a regulator for transposable elements, thereby increasing its contributions to cancer development. This study demonstrated that LKAAEAR1 could potentially be used as a cancer biomarker and therapeutic target.

Les macrophages sont des cellules de l’immunité innée et sont localisés dans la majorité des organes du corps, présentant des fonctions spécifiques dépendant de leur lieu de résidence.Les macrophages d’origine embryonnaire sont la source majeure des macrophages tissulaires et sont capables de se maintenir à long terme dans la plupart des organes adultes.Cependant, il reste certains organes comme le testicule, où l’origine des macrophages n’est pas clairement déterminée. Le testicule est considéré comme un organe immuno-privilégié et a cette nécessité de protéger de tous contacts les spermatozoïdes des cellules immunitaires, qui pourraient induire une auto-immunité.Les macrophages testiculaires (tMφ) contribuent à maintenir ce statut d’organe immuno-privilégié en produisant des cytokines immunosuppressives. Pour ces raisons, les tMφ peuvent être considérés comme des “ gardiens de la fertilité”. Dans les testicules adultes, deux différentes populations de macrophages, nommées interstitielles et péritubulaires, ont été identifiées en se basant sur leurs morphologies et localisations distinctes, mais leur origine et leur mode de développement et de maintenance restent encore inconnus. En combinant des méthodes de traçage cellulaire et la mise au point d’un modèle de transfert adoptif dans des souriceaux, j’ai démontré que les macrophages d’origine embryonnaire contribuaient exclusivement à la population de tMφ interstitielle dès la naissance et que les tMφ péritubulaires proviennent exclusivement de la moelle osseuse. Après avoir caractérisé les tMφ, mes prochaines investigations se porteront sur l’étude des fonctions de chacune de ces deux populations. / Macrophages are innate immune cells residing in most of the organs of the body and ensure proper organ function. Traditionally, it has been known that macrophages can be derived from HSC progenitors in the bone-marrow (BM), but technology using fate-mapping tools has revealed that macrophages can already be generated from embryonic progenitors. Embryo-derived macrophages are a major source of tissue-resident macrophages and can self-maintain during adulthood. The origin of resident macrophages in the testis, however, so far has not been well studied.Importantly, the testis is considered as an immune-privileged organ by protecting the highly immunogenic spermatozoa sequestrated in the seminiferous tubules from the entrance of immune cells. In the adult testis, macrophages participate in the creation of an immune suppressive microenvironment preventing auto-immune attack. Therefore, testicular macrophages tMφ could be considered as the guardians of fertility. Recently,two different macrophage populations have been identified in the adult testis, called interstitial and peritubular, based on their distinct localization and morphology,but their developmental origin and homeostatic maintenance were unknown.Combining the genetic lineage tracing and the neonatal adoptive transfer model, I could demonstrate that the embryo-derived macrophages give rise exclusively to interstitial tMφ. Peritubular tMφ, however, only emerge postnatally from BM-derived progenitors. .My findings provide framework for future investigations into the distinct functions of these two tMφ populations in establishment of immune-privilege as well as the support of spermatogenesis and male hormone production.

Includes bibliographical references (leaves 343-403) / xiii, 403 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Examines the immune priviledged status of the testis, and the likely mechanisms involved in providing this priviledged status. Some new concepts on the possible mechanisms that afford an immunologically protected environment in the rodent testis are presented. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1987

Testis tissue xenografting (TTX) provides a novel in vivo model for the study of testis function, and a previously-unavailable opportunity to produce spermatozoa in the grafts from immature donors of diverse species. The overall objectives of this thesis were to examine a number of factors that potentially affect the outcome of TTX, and to apply TTX using immature bison and deer donors as models for endangered ungulates. The objective of the first experiment was to examine the effects of recipient mouse strain, gender and gonadal status on the outcome of TTX. Eight small fragments of neonatal porcine testis tissue (~5 mg each) were grafted under the back skin of immunodeficient mice of different strains (SCID vs. nude), gender (male vs. female), and gonadal status (intact vs. gonadectomised), using a 2×2×2 factorial design (8 groups, n = 7 mice/group). The xenografts were recovered at 8 mo post-grafting and evaluated for gross and histological attributes. Gonadectomy of the recipients did not affect any of the measured outcomes of TTX (P > 0.05), and data were pooled into four groups based on recipient strain and gender. Overall, male recipient mice had grafts with higher mean (+SEM) recovery rate (97 ± 2.3% vs. 88 ± 2.4%, P = 0.004), weight (348 ± 26.3 vs. 104 ± 27.0 mg, P < 0.001), seminiferous tubular diameter (150 ± 3.3 vs. 108 ± 5.3 mg, P < 0.001), percentage of tubules containing spermatozoa (32 ± 3.2 vs. 6 ± 1.8%, P < 0.001), elongated spermatids (13 ± 1.4% vs. 4 ± 0.8%, P < 0.001), and round spermatids (10 ± 1.2% vs. 6 ± 1.1%, P = 0.006) than female mice. Overall, SCID mice had grafts with higher recovery rate (98 ± 2.4% vs. 87 ± 2.3%, P = 0.001), average weight (292 ± 27.0 vs. 160 ± 26.3 mg, P = 0.001), tubular density (44 ± 3.3 vs. 33 ± 2.1, P = 0.02), percentage of tubular cross-sections containing spermatocytes (27 ± 3.7% vs. 13 ± 2.3%, P = 0.003) than nude mice. Among the four groups of recipients, the grafts from male SCID mice had the highest weight (P < 0.05) and percentage of tubules containing spermatozoa (P < 0.05).<p> The objective of the second experiment was to evaluate the effect of using different numbers of donor testis tissue fragments on the outcome of TTX. Fragments of donor piglet testis tissue were grafted subcutaneously under the back skin of four groups of castrated male nude mice (n = 10/group). Each group of recipient mice received 2, 4, 8, or 16 fragments per mouse. Mice were sacrificed at 8 mo post-grafting, and xenografts were evaluated for physical growth and histological development. The relative weight of the vesicular gland (index) was also determined as a measure of bioactive androgen production by grafts in castrated recipient mice. The overall graft recovery rate was ~94% (range 86-98%) which did not differ among the groups (P > 0.05). The group of mice that received 16 testis tissue fragments had higher mean (+ SEM) graft weights (278 ± 39.4 vs. 106 ± 38.0, P = 0.02), total graft weight (2,443 ± 338.8 vs. 192 ± 76.2, P < 0.001), vesicular gland index (0.5 ± 0.06 vs. 0.1 ± 0.06, P = 0.007), and percentage of seminiferous tubules with round spermatids (11 ± 1.5 vs. 3 ± 1.3, P = 0.03) than the group of mice that received two testis tissue fragments. The objective of the third experiment was to assess the use to salvage testis tissue from neonatal/immature bison or deer donors using TTX into immunodeficient recipient mice as models for closely-related rare or endangered ungulates. Donor testis tissue fragments from two newborn bison calves (Bison bison bison) and a 2-mo-old white-tailed deer fawn (Odocoileus virginianus) were grafted under the back skin of gonadectomised nude mice (n = 15 and n = 7 for bison and deer groups, respectively, 8 testis fragments/mouse). To examine the potential effect of individual donors, we grafted four testis tissue fragments from one bison calf on one side of the recipient and four fragments from the second bison calf on the other side. Single grafts were surgically removed from representative recipient mice every 2 mo for up to 16- and 14 mo post-grafting, for bison and deer groups, respectively. The overall graft recovery rates were 69% and 63% for bison and deer groups, respectively. For bison grafts, a donor effect on efficiency of spermatogenesis was also observed. The weight of bison testis tissue xenografts increased (P < 0.02) ~4-fold by 2 mo and ~10-fold by 16 mo post-grafting, and gradual maturational changes were evident in the form of seminiferous tubule expansion starting at 2 mo, first appearance of spermatocytes at 6 mo, round spermatids at 12 mo, and elongated spermatids at 16 mo post-grafting. Testis tissue xenografts from donor white-tailed deer also showed a gradual development starting with tubular expansion by 2 mo and presence of spermatocytes by 6 mo post-grafting, round and elongated spermatids by 8 mo, followed by fully-formed spermatozoa by 12 mo post-grafting. The timing of complete spermatogenesis roughly corresponded to the reported timing of sexual maturation in these species.<p> Taken together, the findings in this thesis suggest that male SCID mice provide a more suitable recipient model for TTX with neonatal porcine testis tissue; recipient mice can be grafted with as many as 16 testis tissue fragments for optimal results; and that TTX is a feasible strategy for salvaging genetic materials from immature males of rare or endangered ungulates that die prematurely.

Testis tissue xenografting (TTX) provides a novel in vivo model for the study of testis function, and a previously-unavailable opportunity to produce spermatozoa in the grafts from immature donors of diverse species. The overall objectives of this thesis were to examine a number of factors that potentially affect the outcome of TTX, and to apply TTX using immature bison and deer donors as models for endangered ungulates. The objective of the first experiment was to examine the effects of recipient mouse strain, gender and gonadal status on the outcome of TTX. Eight small fragments of neonatal porcine testis tissue (~5 mg each) were grafted under the back skin of immunodeficient mice of different strains (SCID vs. nude), gender (male vs. female), and gonadal status (intact vs. gonadectomised), using a 2×2×2 factorial design (8 groups, n = 7 mice/group). The xenografts were recovered at 8 mo post-grafting and evaluated for gross and histological attributes. Gonadectomy of the recipients did not affect any of the measured outcomes of TTX (P > 0.05), and data were pooled into four groups based on recipient strain and gender. Overall, male recipient mice had grafts with higher mean (+SEM) recovery rate (97 ± 2.3% vs. 88 ± 2.4%, P = 0.004), weight (348 ± 26.3 vs. 104 ± 27.0 mg, P < 0.001), seminiferous tubular diameter (150 ± 3.3 vs. 108 ± 5.3 mg, P < 0.001), percentage of tubules containing spermatozoa (32 ± 3.2 vs. 6 ± 1.8%, P < 0.001), elongated spermatids (13 ± 1.4% vs. 4 ± 0.8%, P < 0.001), and round spermatids (10 ± 1.2% vs. 6 ± 1.1%, P = 0.006) than female mice. Overall, SCID mice had grafts with higher recovery rate (98 ± 2.4% vs. 87 ± 2.3%, P = 0.001), average weight (292 ± 27.0 vs. 160 ± 26.3 mg, P = 0.001), tubular density (44 ± 3.3 vs. 33 ± 2.1, P = 0.02), percentage of tubular cross-sections containing spermatocytes (27 ± 3.7% vs. 13 ± 2.3%, P = 0.003) than nude mice. Among the four groups of recipients, the grafts from male SCID mice had the highest weight (P < 0.05) and percentage of tubules containing spermatozoa (P < 0.05).<p> The objective of the second experiment was to evaluate the effect of using different numbers of donor testis tissue fragments on the outcome of TTX. Fragments of donor piglet testis tissue were grafted subcutaneously under the back skin of four groups of castrated male nude mice (n = 10/group). Each group of recipient mice received 2, 4, 8, or 16 fragments per mouse. Mice were sacrificed at 8 mo post-grafting, and xenografts were evaluated for physical growth and histological development. The relative weight of the vesicular gland (index) was also determined as a measure of bioactive androgen production by grafts in castrated recipient mice. The overall graft recovery rate was ~94% (range 86-98%) which did not differ among the groups (P > 0.05). The group of mice that received 16 testis tissue fragments had higher mean (+ SEM) graft weights (278 ± 39.4 vs. 106 ± 38.0, P = 0.02), total graft weight (2,443 ± 338.8 vs. 192 ± 76.2, P < 0.001), vesicular gland index (0.5 ± 0.06 vs. 0.1 ± 0.06, P = 0.007), and percentage of seminiferous tubules with round spermatids (11 ± 1.5 vs. 3 ± 1.3, P = 0.03) than the group of mice that received two testis tissue fragments. The objective of the third experiment was to assess the use to salvage testis tissue from neonatal/immature bison or deer donors using TTX into immunodeficient recipient mice as models for closely-related rare or endangered ungulates. Donor testis tissue fragments from two newborn bison calves (Bison bison bison) and a 2-mo-old white-tailed deer fawn (Odocoileus virginianus) were grafted under the back skin of gonadectomised nude mice (n = 15 and n = 7 for bison and deer groups, respectively, 8 testis fragments/mouse). To examine the potential effect of individual donors, we grafted four testis tissue fragments from one bison calf on one side of the recipient and four fragments from the second bison calf on the other side. Single grafts were surgically removed from representative recipient mice every 2 mo for up to 16- and 14 mo post-grafting, for bison and deer groups, respectively. The overall graft recovery rates were 69% and 63% for bison and deer groups, respectively. For bison grafts, a donor effect on efficiency of spermatogenesis was also observed. The weight of bison testis tissue xenografts increased (P < 0.02) ~4-fold by 2 mo and ~10-fold by 16 mo post-grafting, and gradual maturational changes were evident in the form of seminiferous tubule expansion starting at 2 mo, first appearance of spermatocytes at 6 mo, round spermatids at 12 mo, and elongated spermatids at 16 mo post-grafting. Testis tissue xenografts from donor white-tailed deer also showed a gradual development starting with tubular expansion by 2 mo and presence of spermatocytes by 6 mo post-grafting, round and elongated spermatids by 8 mo, followed by fully-formed spermatozoa by 12 mo post-grafting. The timing of complete spermatogenesis roughly corresponded to the reported timing of sexual maturation in these species.<p> Taken together, the findings in this thesis suggest that male SCID mice provide a more suitable recipient model for TTX with neonatal porcine testis tissue; recipient mice can be grafted with as many as 16 testis tissue fragments for optimal results; and that TTX is a feasible strategy for salvaging genetic materials from immature males of rare or endangered ungulates that die prematurely.

No description available.