Razvoj radiomarkiranog β-humanog koriogonadotropina

-human chorionic gonadotropin (-hCG) was successively labeled with [67Ga] gallium chloride after conjugation with freshly prepared diethylenetriaminepentaacetic acid dianhydride (ccDTPA). After solid phase purification of the radiolabeled hormone, high performance liquid chromatography showed radiochemical purity higher than 95 % under optimized conditions (specific activity = 2223 TBq mM1, labeling efficiency 80 %). Preliminary in vivo studies (ID g1, %) in male wild-type rats showed marked gonadal uptake of the tracer after 240 minutes in agreement with the biodistribution studies and reported -hCG receptors. Target to blood ratios were 5.1 and 15.2 after 3 and 24 hours, respectively, while target to muscle ratios were 35 and 40 after 3 and 24 hours, respectively.Beta-humani korionski gonadotropin (beta-hCG) uspješno je markiran s [67Ga] galijevim kloridom nakon konjugacije sa svježe priređenim dianhidridom dietilentriaminpentaoctene kiseline (ccDTPA). Nakon čišćenja radiomarkiranog hormona na čvrstoj fazi, radiokemijska čistoća bila je prema HPLC veća od 95 % (specifična aktivnost = 22-23 TBq mM-1, učinkovitost markiranja 80 %). Preliminarni in vivo pokusi (ID g-1, %) na mužjacima divljeg tipa štakora pokazali su da obilježeni hormon značajno ulazi u gonade nakon 240 minuta, što je u suglasnosti s ispitivanjima biodistribucije i podacima o receptorima za beta-hCG. Omjer koncentracija u gonadama i krvi bio je 5,1, odnosno 15,2 nakon 3, odnosno 24 sata, dok je omjer koncentracija u gonadama i mišićima bio 35, odnosno 40 nakon 3, odnosno 24 sata

Consequences of Premature and Persistent Luteinizing Hormone Receptor Activation on Leydig Cell Development

Luteinizing hormone (LH), one of the two gonadotropin hormones released from the pituitary gland, binds its receptor (LHR) in the gonads to initiate steroid hormone production, as well as gametogenesis and ovulation. Mutations of amino acid sequence within the receptor can render it either inactive or constitutively active. All activating mutations result in male-limited precocious puberty. Males afflicted with this condition undergo puberty around 4 years of age, with elevated testosterone levels and premature skeletal development. In order to better understand how chronic ligand-mediated activation of the LHR affects gonadal development and function, a mouse model expressing a yoked hormone-receptor (YHR) complex, engineered by covalently linking the hormone human chorionic gonadotropin to the rat LHR, has been studied. YHR+ males have prepubertally elevated testosterone and decreased gonadotropin levels. Histological evaluation of the testes of these animals show significantly smaller seminiferous tubules and Leydig cell clusters. Finally, testis gene expression analysis revealed a significant decrease in the relative mRNA expression of three Leydig cell specific genes. Based on these results, it was hypothesized that premature activation of the LHR impairs postnatal Leydig cell development. In the testis there are two morphologically and developmentally distinct populations of Leydig cells, the fetal and the adult. The first objective of this study was to quantify the populations of cells in the adult Leydig cell lineage in both the YHR+ and the WT controls. Real-time RT-PCR, for markers of the immature and adult Leydig cell populations, as well as Leydig cell quantification, suggested a delay in adult Leydig cell development. Interestingly, there was a significant increase in the fetal Leydig cell population in the YHR+ mice. The second objective was to determine if the decrease in the adult population is due to either a decrease in proliferation or an increase in apoptosis in the YHR+ animal. There was not a difference in apoptosis between the WT and the YHR+ at any age examined, however, there was a decrease in progenitor Leydig cell proliferation in the YHR+ animals at 2 weeks of age. The final objective was to determine if elevated neonatal testosterone levels impairs the development of the adult Leydig cell population. Seven-day old WT pups were subjected to testosterone supplementation via subdermal implant. Quantification of the total Leydig cell population revealed a significant decrease in the number of adult Leydig cells in the testosterone-treated group similar to that seen in the YHR+ animal. Taken together, these data suggest that elevated neonatal testosterone levels resulting from premature LHR activation inhibits the proliferation of progenitor Leydig cells, resulting in fewer adult Leydig cells in the YHR+ animals

Quantifying Annual Affordability Risk of Major Defense Programs

To a first approximation, acquisition programs never spend what they originally said they would spend when they began. In fact, the error bars around an initial cost estimate are much larger than is generally understood, once program cancellations, restructurings, truncations, and block upgrades have been accounted for. Worse yet, all of this uncertainty arises in a context where programs must fit within annual budgets;it is not enough to only spend as much as you said you would; you must also spend it when you said you would, or problems ensue. We have developed a methodology that uses historical program outcomes to characterize the year-by-year budget risk associated with a major acquisition program. This methodology can be applied to both development costs and procurement costs and can be extended to understand the aggregate affordability risk of portfolios of programs. The method allows Resource Managers to estimate annual budget risk levels, required contingency amounts to achieve a target probability of staying within a given budget, and many other relevant risk metrics for programs. It also allows policy makers to predict the impact on program affordability of proposed changes in how contingency funds are managed.Naval Postgraduate School Acquisition Research Progra