Preservation and transplantation of porcine testis tissue

Grafting of immature mammalian testis tissue to mouse hosts can preserve the male germline. To make this approach applicable to a clinical or field situation, it is imperative that the testis tissue and/or spermatozoa harvested from grafted tissue are preserved successfully. The aim of the present study was to evaluate protocols for the preservation of testis tissue in a porcine model. Testis tissue was stored at 4 degrees C for short-term preservation or cryopreserved by slow-freezing, automated slow-freezing or vitrification for long-term storage. Preserved tissue was transplanted ectopically to mouse hosts and recovered xenografts were analysed histologically. In addition, spermatozoa were harvested from xenografts and cryopreserved. Total cell viability and germ cell viability remained high after tissue preservation. Complete spermatogenesis occurred in xenografts preserved by cooling up to 48 h, whereas spermatogenesis progressed to round spermatids in the xenografts that were frozen-thawed before grafting. Approximately 50% of spermatozoa harvested from xenografts remained viable after freezing and thawing. The in vivo developmental potential of cryopreserved tissue was reduced despite high post-thaw viability. Therefore, it is important to evaluate germ cell differentiation in vivo in addition to cell viability in vitro when optimising freezing protocols for testis tissue.

Air pressure pulsation solid state fermentation of feruloyl esterase by Aspergillus niger

Air pressure pulsation solid state fermentation (APP-SSF) was applied to produce feruloyl esterase (FAE) by Aspergillus niger. With the optimization of some variables by orthogonal design, the optimal condition obtained was 0.2 MPa (gauge pressure) of high pressure intensity, 30 min of low pressure duration and 20s of high pressure duration. Based on the optimized condition, the APP-SSF achieved the reasonable enzyme yield of 881 mU/g at 48 h, which was 58% more than that by static solid state fermentation (static SSF) at 72 h. By comparison of two fermentation methods in temperature, O(2) and CO(2) concentration, and respiration intensity, it was concluded that APP-SSF enhanced heat and mass transfer of fermentation system and strengthened the metabolism of microorganisms. The APP-SSF had a greatly positive effect on FAE production by A. niger, by enhancing mass and heat transfer and activating growth and metabolism.

[E-cadherin as a novel surface marker of spermatogonial stem cells]

Spermatogenesis is a fundamental biological process that ensures gee transmission from one generation to another trough gametes. This process relies on a rare population of testicular cells, called spermatogonial stem cells (SSCs), that self-renew throughout adult male life and differentiate into mature gametes. Despite the longstanding research of SSCs, their biological properties remain largely unknown which is partly due to very limited availability of these cells. Here we show that cell adhesion protein E-cadherin is a highly specific surface marker of mouse SSCs, which can be successfully used for their enrichment.

Callus distraction for humeral nonunion with bone loss and limb shortening caused by chronic osteomyelitis

Nonunion of the humerus with bone loss and shortening due to osteomyelitis is rare but difficult to treat. We describe our experience with a callus distraction technique using a monolateral external fixator for the treatment of this condition. Between October 1994 and January 2004, 11 patients were treated. There were seven males and four females, with a mean age of 14 years (10 to 17). The mean bone loss was 1.9 cm (1 to 2.7) and the mean length discrepancy in the upper limb was 5.6 cm (3.5 to 8.0). The mean follow-up was for 106 months (54 to 166). The mean external fixation index was 34.8 days/cm (29.8 to 40.5). The mean lengthening was 9.5 cm (5.5 to 13.4). There were seven excellent results, three good and one poor. There were nine excellent functional results and two good. The treatment of humeral nonunion with bone loss and shortening due to osteomyelitis by callus distraction is a safe and effective means of improving function and cosmesis.

Genetic analysis and gene mapping of a rice few-tillering mutant in early backcross populations (Oryza sativa L.)

A rice mutant, G069, characteristic of few tiller numbers, was found in anther culture progeny from the F(1) hybrid between an indica-japonica cross, Gui630x02428. The mutant has another two major features: delayed tillering development and yellowing apex and margin on the mature leaves. As a donor parent, G069 was further backcrossed with the recurrent parent,02428, for two turns to develop aBC (2)F(2) population. Genetic analysis in the BC (2)F(2) population showed that the traits of few-tillering and yellowing apex and margin on the mature leaves were controlled by one recessive gene. A pool of equally mixed genomic DNA, from few-tillering individual plants in BC (2)F(2), was constructed to screen polymorphism with simple sequence repeat (SSR) markers in comparison with the 02428 genome. One SSR marker and three restriction fragment length polymorphism (RFLP) markers were found possibly linked with the recessive gene. By using these markers, the gene of few-tillering was mapped on chromosome 2 between RFLP marker C424 and S13984 with a genetic distance of 2.4 cM and 0.6 cM, respectively. The gene is designated ft1.

Molecular cloning and identification of naturally occurring human antisenseangiopoietin-1: Gna-1

One novel cDNA fragment was obtained from vascular endothelial cells by differential display reverse transcription PCR technique. By using this fragment as probe, we screened the human artery cDNA library and obtained one cDNA clone which is 2198 bp in length. After sequencing and homology researching, we found that the clone contained a region of 851 bp in length complementary to that of humanangiopoietin-1 cDNA, encoding the partial fibrinogen-like domain and 3' non-translational region. It was inferred that this clone was a naturally occurring antisense RNA of humanangiopoietin-1, designated asGna-1. Gna-1 does not encode protein. The transcription ofGna-1 in human umbilical vein endothelial cells and ECV304 cells was confirmed by RT-PCR method.Gna-1 may be involved in regulating the function ofangiopoietin-1, and play a significant role in angiogenesis.

1 XENOGRAFTING OF ADULT MAMMALIAN TESTIS TISSUE

Testis tissue grafting presents an option for preservation of genetic material when sperm recovery is not possible. Grafting of testis tissue from sexually immature males to immunodeficient mice results in germ cell differentiation and production of fertilization-competent sperm from different mammalian species (Honaramooz et al. 2002 Nature 418, 778–781). However, the efficiency of testis tissue xenografting from adult donors has not been critically evaluated. Spermatogenesis was arrested at meiosis in grafts from mature horses (Rathi et al. 2006 Reproduction 131, 1091–1098) and hamsters (Schlatt et al. 2002 Reproduction 124, 339–346), and no germ cell differentiation occurred in xenografts of adult human testis tissue (Schlatt et al. 2006 Hum. Reprod. 21, 384–389). The objective of this study was to investigate survival and germ cell differentiation of testis xenografts from sexually mature donors of different species. Small fragments of testis tissue from 10 donor animals of 5 species were grafted under the back skin of immunodeficient, castrated male mice (n = 37, 2–6/donor). Donors were pig (8 months old), goat (18 months old and 4 years old) (n = 2), bull (3 years old), donkey (13 months old), and rhesus monkey (3, 6, 11, and 12 years old). At the time of grafting, donor tissue contained elongated spermatids, albeit to different degrees (>75% of seminiferous tubules in testis tissue from pig, goat, bull, and 6–12-year-old monkeys, and 33 or 66% of tubules in tissue from donkey or 3-year-old monkey, respectively). Grafts were recovered <12 weeks (n = 14 mice), 12–24 weeks (n = 16 mice), and >24 weeks (n = 7 mice) after grafting and classified histologically as completely degenerated (no tubules found), degenerated tubules (only hyalinized seminiferous tubules observed), or according to the most advanced type of germ cell present. Grafts from pig, goat, bull, and 6–12-year-old monkeys contained >60% degenerated tubules or were completely degenerated at all time points analyzed. In contrast, in grafts from the 3-year-old monkey, only 18% of tubules were degenerated, 14% contained Sertoli cells only, 64% contained meiotic, and 4% haploid germ cells at 24 weeks after grafting. Similarly, donkey testis grafts recovered 12–24 weeks after grafting contained <2% degenerated tubules, 46% of tubules had Sertoli cells only, 45% contained meiotic, and 7% haploid germ cells. These results show that survival and differentiation of germ cells in testis grafts from sexually mature mammalian donors is poor. However, better graft survival and maintenance of spermatogenesis occurred in donor tissue from donkey and 3-year-old monkey that were less mature at the time of grafting. Therefore, species and age-related differences appear to exist with regard to germ cell survival and differentiation in xenografts from adult donors. This work was supported by USDA/CSREES 03-35203-13486, NIH/NCRR 5-R01-RR17359-05, the Spanish Ministry of Education, and Science (BES-2004-4112).

Evolution of VHL tumourigenesis in nerve root tissue

Haemangioblastomas are the key central nervous system manifestation of von Hippel-Lindau (VHL) disease, which is caused by germline mutation of the VHL gene. We have recently shown that 'tumour-free' spinal cord from patients with VHL disease contains microscopic, poorly differentiated cellular aggregates in nerve root tissue, which we descriptively designated 'mesenchymal tumourlets'. Here we have investigated spinal cord tissue affected by multiple tumours. We show that a small subset of mesenchymal tumourlets extends beyond the nerve root to form proliferative VHL-deficient mesenchyme and frank haemangioblastoma. We thus demonstrate that tumourlets present potential, but true precursor material for haemangioblastoma. We further show that intraradicular tumourlets consist of scattered VHL-deficient cells with activation of HIF-2alpha and HIF-dependent target proteins including CAIX and VEGF, and are associated with an extensive angiogenic response. In contrast, activation of HIF-1alpha was only observed in the later stages of tumour progression. In addition, ultrastructural examination reveals gradual transition from poorly differentiated VHL-deficient cells into vacuolated cells with a 'stromal' cell phenotype. The evolution of frank haemangioblastoma seems to involve multiple steps from a large pool of precursor lesions.

Germ cell development in equine testis tissue xenografted into mice

Grafting of testis tissue from immature animals to immunodeficient mice results in complete spermatogenesis, albeit with varying efficiency in different species. The objectives of this study were to investigate if grafting of horse testis tissue would result in spermatogenesis, and to assess the effect of exogenous gonadotropins on xenograft development. Small fragments of testis tissue from 7 colts (2 week to 4 years of age) were grafted under the back skin of castrated male immunodeficient mice. For 2 donor animals, half of the mice were treated with gonadotropins. Xenografts were analyzed at 4 and 8 months post-transplantation. Spermatogenic differentiation following grafting ranged from no differentiation to progression through meiosis with appearance of haploid cells. Administration of exogenous gonadotropins appeared to support post-meiotic differentiation. For more mature donor testis samples where spermatogenesis had progressed into or through meiosis, after grafting an initial loss of differentiated germ cells was observed followed by a resurgence of spermatogenesis. However, if haploid cells had been present prior to grafting, spermatogenesis did not progress beyond meiotic division. In all host mice with spermatogenic differentiation in grafts, increased weight of the seminal vesicles compared to castrated mice showed that xenografts were releasing testosterone. These results indicate that horse spermatogenesis occurs in a mouse host albeit with low efficiency. In most cases, spermatogenesis arrested at meiosis. The underlying mechanisms of this spermatogenic arrest require further investigation.

Proteomic profiling distinguishes astrocytomas and identifies differential tumor markers

Methods to permit more precise delineation of astrocytomas of different grades may have therapeutic utility. The authors selectively microdissected pure populations of cells from normal brain and astrocytomas. They performed two-dimensional protein gel electrophoresis (2DGE) followed by protein sequencing. Differential expression was confirmed immunohistochemically. 2DGE identified proteomic patterns and proteins that differentiated normal brain from tumor and distinguished astrocytomas of increasing grade.

A random search methodology for examining parametric uncertainty in water quality models

The advent of the modern high-speed digital computer has tremendously enhanced the utility of Monte Carlo methods for evaluating complex environmental simulation models. In particular, random searching is becoming popular, as thousands of model runs can now be executed quickly and with minimal effort. Indeed, the issues of computational burden and inefficiency, hitherto the bane of random searching, are now receding. This paper presents one such method, uniform covering by probabilistic rejection (UCPR), which combines a pure random search with a probabilistic rejection algorithm that significantly enhances its efficiency. Using nearest-neighbor distances, an ensemble of points in a predefined parameter sampling domain migrates to locate and define a final distribution of optimal parameter vectors, thus providing a realistic depiction of parameter uncertainty. In a prototypical case study of the Oconee River (Georgia, USA), UCPR and regionalized sensitivity analysis, are employed for identifying the parameters of sediment-transport-associated nutrient dynamics, a dynamic river water quality model. Results indicate the existence of a complex interactive parameter structure, evidenced by multiple sets of optimal points widely dispersed over a broad domain of feasible parameter values.

93 CALCIUM REMOVAL INCREASES THE PROTECTIVE EFFECTS OF β-CYCLODEXTRIN PLUS CHOLESTEROL ON PORCINE SPERM DURING COLD SHOCK

Porcine sperm are extremely sensitive to the damaging effects of cold shock and cryopreservation. Cholesterol-binding molecules, such as 2-hydroxypropyl-�-cyclodextrin (HBCD), improve post-thaw and post-cooling porcine sperm viability when added to an egg yolk-based extender, but also enhance sperm capacitation in other species. Depending upon the environmental cholesterol content, HBCD can act either as a cholesterol shuttle or sink to increase or decrease, respectively, sperm plasma membrane cholesterol content. Increasing the sperm cholesterol to phospholipid ratio reduces cold shock sensitivity whereas decreasing the ratio initiates the process of sperm capacitation. An increase in protein tyrosine phosphorylation correlates with sperm capacitation and has been shown to be dependent upon the presence of extracellular calcium. Sperm intracellular calcium also increases during cold shock. The objective of this study was to determine the combined effects of extracellular calcium and membrane cholesterol manipulation on porcine sperm viability and protein tyrosine phosphorylation following cold shock (10�C for 10 min). Viability was assessed using CFDA/propidium iodide staining. Protein tyrosine phosphorylation, previously shown to correlate with porcine sperm capacitation, was evaluated via antiphosphotyrosine (clone 4G10) immunoblots. We report here that following cold shock, porcine sperm incubated in defined medium containing both 0.8 mM HBCD and 0.5 mM cholesterol 3-sulfate (ChS) incubated in the absence of added extracellular calcium and the presence of 6 mM EGTA have significantly improved viability (90.5 � 6.3%, n = 3) when compared with cold-shocked sperm incubated in either the same medium with calcium (46.1 � 3.8%), without HBCD or ChS (26.5 � 7.4% with calcium; 46.5 � 13.1% without calcium), or with HBCD alone (17.0 � 7.4% with calcium, 36.8 � 7.5% without calcium). As we have found previously, treatment with 0.8 mM HBCD plus 0.5 mM ChS completely inhibited the increase in protein tyrosine phosphorylation induced by the cold shock treatment. Although protein tyrosine phosphorylation correlates with porcine sperm capacitation, the ability of cold shock treatment to induce the same phosphorylation pattern indicates that other processes or pathways may contribute to its appearance. Removing extracellular calcium consistently decreased, but did not completely eliminate, the protein tyrosine phosphorylation induced by cold shock. These results indicate that cold shock-induced protein tyrosine phosphorylation is not dependent upon, but can be modulated by, extracellular calcium. The combined effects of calcium, HBCD and ChS on viability suggest that porcine sperm viability following cold shock is best maintained by removing extracellular calcium and increasing membrane cholesterol content via the cholesterol shuttle activity of HBCD. This work was supported by grants from PA Dept. Ag. (ME 443291) and the NIH (5-K08-HD041430).

309 THE SPERMATOGENIC CYCLE IN MAMMALIAN TESTIS XENOGRAFTS

Grafting of immature testis tissue from different mammalian donor species into mouse hosts results in production of spermatozoa from the donor species. Xenografting of testis tissue from rhesus monkeys, pigs, and sheep accelerates sperm production. To determine whether this shortened time to sperm production is due to the reduced spermatogenic cycle length, we applied bromodeoxyuridine (BrdU) incorporation to analyze the spermatogenic cycle in porcine and ovine testis xenografts. Testes from 1-2-week-old Yorkshire cross pigs and 1-week-old Suffolk sheep were cut into small fragments (approximately 1 � 1 � 2 mm) and eight fragments were grafted under the back skin of each castrated male immunodeficient NCR nude recipient mouse (n = 7 for pig, n = 5 for sheep). Mice were given BrdU (100 mg/kg i.p.) at 7 months (porcine tissue) or 6 months (ovine tissue) post-transplantation. Mice carrying porcine tissue were sacrificed 1 h, 9 days or 18 days after BrdU injection. Mice with ovine testicular tissue were sacrificed 1 h, 11 days or 22 days after BrdU injection. Analysis time points were chosen based on the reported length of the spermatogenic cycle in pigs and sheep (approximately 9 days and 11 days, respectively). All eight stages of the spermatogenic cycle were analyzed to identify the most advanced germ cells labeled in each time period after BrdU injection. All seminiferous tubules containing full spermatogenesis were analyzed. Histologically, 51.8% (range 7 to 98%, n = 2040 tubules) of seminiferous tubules from porcine grafts, and 64.4% (range 2 to 92%, n = 2903 tubules) of seminiferous tubules from ovine grafts presented complete spermatogenesis. In porcine grafts, the most advanced germ cells labeled 1 h after BrdU injection were primary spermatocytes in pre-leptotene/leptotene at stage I of the spermatogenic cycle. At 9 days and 18 days after injection, the most advanced labeled germ cells were primary spermatocytes at pachytene at stage I and elongating spermatids at late stage II, respectively. In ovine grafts, the most advanced labeled germ cells at 1 h, 11 days and 22 days were pre-leptotene/leptotene at stage II, primary spermatocytes at the pachytene at stage I and elongating spermatids at stage II, respectively. These results indicate that each spermatogenic cycle in porcine and ovine testis xenografts lasts around 9 days and 11 days, respectively. Therefore, the length of the spermatogenic cycle is conserved in porcine and ovine testis xenografts and shortened time to sperm production is likely due to accelerated maturation of the testicular somatic components, such as Sertoli cells. This work was supported by NIH R01 RR17359-01.