Energy allocation strategy of skipjack tuna Katsuwonus pelamis during their reproductive cycle.

The lipid composition of somatic and reproductive tissues was determined for female skipjack tuna Katsuwonus pelamis caught in the western Indian Ocean between latitude 10° N and 20° S and longitude 40° and 70° E. The highest total lipid (TL) contents were in the liver and gonads, with white muscle levels approximately three-fold lower. Three lipid classes dominated: triacylglycerols (TAG), sterol esters and wax esters (SE-WE) and phospholipids (PL). Collectively, these accounted for between 70 and 80% of TLs. Changes in lipid concentrations were evaluated over the maturation cycle. Immature fish had the lowest gonad and liver TL levels; concentrations of TL, TAG, SE-WE and PL accumulated from immature to mature (spawning-capable) phase, reflecting sustained vitellogenic activity of the liver and a transfer of lipids to developing oocytes from the onset of vitellogenesis. Gonado-somatic and hepato-somatic indices were positively correlated with each other and positively related to TL in the gonads and liver. Fulton's condition index and lipid concentrations in muscle did not vary significantly over the maturation cycle; fat content in the main storage tissues was undepleted as the ovary developed. Hence, K. pelamis apparently supports reproduction directly from food intake over the breeding season. In the gonads, reserve lipids (SE-WE and TAG) and sterols were related to batch fecundity but this was not the case for somatic and hepatic tissues. These results suggest that K. pelamis utilizes an income breeding strategy.

Responses of diploid and triploid Pacific oysters Crassostrea gigas to Vibrio infection in relation to their reproductive status.

Several Vibrio species are known to be pathogenic to the Pacific oyster Crassostrea gigas. Survival varies according to pathogen exposure and high mortality events usually occur in summer during gametogenesis. In order to study the effects of gametogenetic status and ploidy (a factor known to affect reproduction allocation in oysters) on vibriosis survival, we conducted two successive experiments. Our results demonstrate that a common bath challenge with pathogenic Vibrio splendidus and Vibrio aestuarianus on a mixture of mature, spawning and non-mature oysters can lead to significant mortality. Previous bath challenges, which were done using only non-mature oysters, had not produced mortality. Immunohistochemical analyses showed the affinity of Vibrio for gonadic tissues, highlighting the importance of sexual maturity for vibriosis infection processes in oysters. Mortality rate results showed poor repeatability between tanks, however, in this bath challenge. We then tested a standardized and repeatable injection protocol using two different doses of the same combination of two Vibrio species on related diploid and triploid oysters at four different times over a year. Statistical analyses of mortality kinetics over a 6-day period after injection revealed that active gametogenesis periods correspond to higher susceptibility to vibriosis and that there is a significant interaction of this seasonal effect with ploidy. However, no significant advantage of triploidy was observed. Triploid oysters even showed lower survival than diploid counterparts in winter. Results are discussed in relation to differing energy allocation patterns between diploid and triploid Pacific oysters.

Titanium nitride oxide coating on rough titanium stimulates the proliferation of human primary osteoblasts.

OBJECTIVES: Titanium is widely used in contemporary endosseous implantology and there is considerable thrust to further promote osseointegration by implant surface modifications. The aim of this study was to evaluate the effect of a titanium-nitride-oxide (TiNOx) coating on commercially pure microroughened titanium by assessing the proliferation and differentiation of human primary osteoblasts. MATERIALS AND METHODS: Cell proliferation, gene expression, alkaline phosphatase activity, osteoprotegerin and osteocalcin secretion were analyzed for a time course of 3 weeks, with or without additional stimulation by 1.25(OH)(2) vitamin D(3) 100 nM. RESULTS: A 1.5-fold increase in the proliferation rate of cells grown on TiNOx-coated titanium as compared with uncoated surfaces was observed. SEM views indicated that the cells' normal morphology with their numerous extensions was maintained. The differentiation process on the TiNOx surface was only affected to a minor degree and translated into a slight delay in osteoblast maturation when compared to uncoated titanium. CONCLUSION: Pending confirmation of these results in vivo, TiNOx coatings could potentially accelerate and enhance osseointegration.

Coincidence of seminoma and sarcoidosis: a myth or fact?

A patient with a stage II seminoma of the testis was treated with a routine orchidectomy and irradiation. One and a half years later enlarged mediastinal lymph nodes were noted. Additional staging showed no other abnormalities and a mediastinoscopy was performed. The initial histologic examination confirmed the clinically suspected diagnosis of sarcoidosis. However, additional immunohistochemical analysis unexpectedly demonstrated that there was also a microscopic relapse of the testis tumor. The literature concerning the co-incidence of non-caseating granulomas and testis tumors is reviewed. It is not clear, whether the granulomas indicate the presence of genuine idiopathic sarcoidosis or whether they reflect a sarcoid-like reaction against tumor antigens. The immunopathogenesis of sarcoid formation and its possible biologic significance in obtaining a spontaneous tumor remission is discussed.