Postdispersal removal and germination of seed dispersed by Cercopithecus nictitans in a West African Montane Forest.

Factors that determine the effectiveness of primates as seed dispersers include (i) the microsite into which they deposit seed, (ii) secondary removal of seed by other taxa and (iii) the effect of gut passage and/or spitting on subsequent seed germination. This contribution evaluated these factors in the little studied putty-nosed monkey, Cercopithecus nictitans, in a Nigerian montane forest. Field experiments showed that C. nictitans has greatly increased in its importance as a disperser of medium-sized seed (>5 mm) because other large primates have been hunted to near extinction. C. nictitans disperses seed across habitats by spitting and defaecation. Rates of secondary seed removal were high for all seed species irrespective of the presence or absence of C. nictitans faecal matter, size or microsite variables. Gut passage enhanced germination relative to hand-cleaned seed, while spitting had either no effect or decreased the germination rate.

Association of preoperative plasma levels of insulin-like growth factor I and insulin-like growth factor binding proteins-2 and -3 with prostate cancer invasion, progression, and metastasis.

PURPOSE: We tested the hypothesis that preoperative plasma levels of insulin-like growth factor (IGF) binding protein (BP)-2 or IGFBP-3 would predict cancer stage and prognosis in patients undergoing radical prostatectomy. MATERIAL AND METHODS: Plasma levels of IGF-I, IGFBP-2, and IGFBP-3 were measured preoperatively in 120 consecutive patients who underwent radical prostatectomy for clinically localized disease, postoperatively in 51 of these patients, in 44 healthy men, in 19 patients with metastases to regional lymph nodes, and in 10 patients with bone metastases. RESULTS: Plasma IGFBP-3 levels were lowest in patients with bone metastases (P < or = .043). IGFBP-2 levels were elevated in prostate cancer patients compared with healthy subjects (P < or = .006). However, within the group of prostatectomy patients, preoperative plasma IGFBP-2 levels were lower in patients with advanced disease (P < or = .033), were inversely correlated with prostatic tumor volume (P =.037), and declined after prostate removal (P =.044). Lower preoperative IGFBP-2 and IGFBP-3 levels and biopsy Gleason score were independent predictors of biochemical progression (P =.043, P =.040, and P =.020, respectively). In patients with disease progression, preoperative plasma IGFBP-3 levels were lower in those with aggressive than in those with nonaggressive failure (P =.042). CONCLUSION: Elevation of plasma IGFBP-2 levels in prostate cancer patients apparently is due to increased release directly from the prostate. For patients with clinically localized prostate cancer, preoperative plasma IGFBP-2 levels are inversely associated with biologically aggressive disease and disease progression. Preoperative plasma IGFBP-3 levels were decreased in patients with prostate cancer metastases and were an independent predictor of biochemical progression after surgery, presumably because of an association with occult metastatic disease present at the time of radical prostatectomy.

De novo testosterone production in luteinizing hormone receptor knockout mice after transplantation of leydig stem cells.

Mesenchymal stem cells or Leydig cell progenitors are rare and difficult to isolate from adult testes. The property of differential efflux of Hoechst 33342 dye by the multi-drug-like transporter enriches murine hematopoietic stem cells from bone marrow. Our work on testicular cell transplantation suggests that the "Hoechst dim" side population (SP) also contains Leydig stem cells or progenitors that proliferate and differentiate into mature functional Leydig cells. We harvested testicular cells from cryptorchid ROSA26 mice, stained them with Hoechst dye, and isolated the cell population that excludes the dye using flow cytometry. Mice with targeted deletion of the LH receptor (LHR) gene were used as the recipients of the transplanted cells. These mice are hypogonadal and infertile. Both testicular SP and non-SP cells were transplanted into the interstitium of the LHR knockout recipients' testes. Serial serum testosterone assays revealed a significant increase in the circulating testosterone levels and restoration of spermatogenesis in the LHR-knockout recipients transplanted with the SP cells compared with that of those transplanted with non-SP. A SP cell concentration- and time-dependent increase in circulating testosterone was observed. This demonstrates the successful transplantation of functional putative Leydig stem cells into a hypogonadal recipient. The increase in testosterone concentration indicates the de novo synthesis of androgen by the transplanted SP cells. This method offers a novel technique to isolate Leydig stem cells and to study Leydig cell development.