Investigation of Senescence in Canine Fibroblasts

Introduction and Aims:  Primary and secondary cell cultures of canine dermal fibroblasts were used to test the suitability of several senescence-linked cellular markers to characterize the chronological age of dogs. In further studies these markers will be used to test the hypothesis that senescence-linked changes at the cellular level are representative for the observed inverse relationship of body mass and life expectancy in different dog breeds.
Methods:  In this study standardized skin samples of Beagles were used to analyse the cell morphology and several senescence-linked parameters as Cumulative Population Doubling Level, Highest Population Doubling Level, Culture Doubling Time and Life Span Completed to determine the replicative potential of fibroblasts. The samples were divided by the age of the donors into three groups ('young', 'middle' and 'old').
Results:  There are notable differences between the replicative potential of young and old Beagles at the cellular level. Preliminary results show that in fibroblast cultures obtained from the young group the highest population doubling level is higher and the culture doubling time is shorter then in cultures of the old group. Cultures from the young and middle-aged group cannot be distinguished by the measured parameters. For final results the complete statistical analysis of sampled data has to be carried out.
Conclusions:  Our results demonstrate a relationship between the chronological age of the skin donor and the replicative potential of the dermal fibroblasts. Therefore cellular senescence-linked markers could serve as suitable tools to compare the age of individual dogs of different breeds.     

Die Kapillarisierung des M. pectoralis der Pute (Meleagris galloopavo) vom Schlupf bis zum 280. Lebenstag

The capillarization of the M. pectoralis was examined in the turkey as it changed with age. Examined was the density of the muscles fibers (per mm2), the density of the capillaries (per mm2) and the quotient muscle fibers/capillaries. In accordance with the sequence of the original data four functions of organismic growth (slightly altered) were utilized for the approximation of the data for descending amounts: Pütter/Bertalanffy (1920, 1934); Richards (1959); Janoschek enlarged after Sager (1980) and Richards enlarged after Sager (1980). The approximations were made via nonlinear regressions, whereby the sum of the error amounts and the sums of the error squares served as criteria of quality. The results including the deduced initial and end amounts are combined in tables which also contain the parameter of the way the computations were conducted.     

Vascular-targeted photodynamic therapy (VTP) of a canine-transmissible venereal tumour in a murine model with Pd-bacteriopheophorbide (WST09)

Treatment of canine‐transmissible venereal tumour (CTVT) with local vascular‐targeted photodynamic therapy (VTP) using Pd‐bacteriopheophorbide (WST09) as a drug is suggested as an alternative to conventional chemotherapy. Male CD1 nude mice were subcutaneously grafted with the xenograft‐transmissible canine venereal tumour (XTVT). The VTP protocol delivered once consisted of intravenous administration of WST09 (10 mg kg^?1) followed by immediate local illumination with a diode laser (763 nm). Controls included animals treated with light or WST09 alone. Macroscopic and microscopic evaluations of tumour response were conducted 10, 24 and 48 h after treatment. Upon VTP, tumours underwent necrosis that lasted 8–10 days and exhibited complete healing by 25–35 days, reaching an overall long‐term cure rate (83%) by 90 days after treatment. This study suggests that VTP with WST09 can efficiently treat CTVT in a single session, as compared with 4–6 sessions of chemotherapy and thus may be feasible for common veterinary practice, particularly under ambulatory conditions.     

Two chromosome segments confer multiple potyvirus resistance in maize

Potyviruses cause serious yield losses in maize production worldwide. While the maize dwarf mosaic virus (MDMV) predominates in the USA, sugarcane mosaic virus (SCMV) is a major pathogen in China and Germany. In previous studies, inbred FAP1360A revealed complete resistance against both MDMV and SCMV. Two major SCMV resistance genes, Scmv1 and Scmv2, were located on chromosomes 6 and 3, respectively, in populations derived from crosses with the susceptible inbred line F7. For validation of these results obtained in segregating backcross‐ or F_2:3‐populations, near‐isogenic lines to F7 have been produced after one initial cross to FAP1360A by repeated backcrossing to F7, phenotypic selection for SCMV resistance, and marker‐assisted selection for the Scmv1 and Scmv2 regions from FAP1360A. The near‐isogenic line F7R has been studied in detail both at the genomic level and for resistance to different potyviruses. Based on 112 polymorphic simple sequence repeat markers, F7R received genomic segments introgressed from FAP1360A exclusively in the Scmv1 and Scmv2 chromosomal regions. F7R conferred complete resistance to SCMV and MDMV, but also to zea mosaic virus and to systemic infection by wheat streak mosaic virus. FAP1360A, F7, F7R were not systemically infected by high plains virus. Thus, introgression of Scmv1 and Scmv2 from FAP1360A into F7 was sufficient to generate the first potyvirus multiresistant European Flint line reported so far.     

Population viability, ecological processes and biodiversity: Valuing sites for reserve selection

No-take reserves constitute one tool to improve conservation of marine ecosystems, yet criteria for their placement, size, and arrangement remain uncertain. Representation of biodiversity is necessary in reserve planning, but will ultimately fail for conservation unless factors affecting species’ persistence are also incorporated. This study presents an empirical example of the divergent relationships among multiple metrics used to quantify a site’s conservation value, including those that address representation (habitat type, species richness, species diversity), and others that address ecological processes and viability (density and reproductive capacity of a keystone species, in this case, the black chiton, Katharina tunicata). We characterized 10 rocky intertidal sites across two habitats in Barkley Sound, British Columbia, Canada, according to these site metrics. High-richness and high-production sites for K. tunicata were present in both habitat types, but high richness and high-production sites did not overlap. Across sites, species richness ranged from 29 to 46, and adult K. tunicata varied from 6 to 22 individuals m⁻². Adult density was negatively correlated with species richness, a pattern that likely occurs due to post-recruitment growth and survival because no correlation was evident with non-reproductive juveniles. Sites with high adult density also contributed disproportionately greater potential reproductive output (PRO), defined by total gonad mass. PRO varied by a factor of five across sites and was also negatively correlated with species richness. Compromise or relative weighting would be necessary to select valuable sites for conservation because of inherent contradictions among some reserve selection criteria. We suspect that this inconsistency among site metrics will occur more generally in other ecosystems and emphasize the importance of population viability of strongly interacting species.     

On the spatial distribution of citrus tristeza virus disease

The spatial spread of citrus tristeza virus (CTV) disease was studied using data from two infected groves. Statistical analysis indicated a spatial grouping of infected trees. A gamma distribution was fitted to the empirical distribution of the distances between nearest infected neighbors. The findings suggest that, after locating a newly infected tree, additional inspections to detect CTV should be carried out mainly on trees within 14 m of that tree.     

The global impact of scaling up HIV/AIDS prevention programs in low- and middle-income countries

A strong, global commitment to expanded prevention programs targeted at sexual transmission and transmission among injecting drug users, started now, could avert 28 million new HIV infections between 2005 and 2015. This figure is more than half of the new infections that might otherwise occur during that period in 125 low- and middle-income countries. Although preventing these new infections would require investing about U.S.$122 billion over this period, it would reduce future needs for treatment and care. Our analysis suggests that it will cost about U.S.$3900 to prevent each new infection, but that this will produce a savings of U.S.$4700 in forgone treatment and care costs. Thus, greater spending on prevention now would not only prevent more than half the new infections that would occur from 2005 to 2015 but would actually produce a net financial saving as future costs for treatment and care are averted.