LIVESTOCK PRICING IN THE NORTHERN KENYAN RANGELANDS

This paper uses detailed, transactions-level data and a structural-heteroskedasticity-in-mean model to identify the determinants of livestock producer prices for pastoralists in the drylands of northern Kenya. The empirical results confirm the importance of animal characteristics, periodic events that predictably shift local demand or supply, and especially rainfall on the prices pastoralists receive for animals. Price risk premia are consistently negative in these livestock markets. The imposition of quarantines has a sharp negative effect on expected producer prices in the pastoral areas, revealing a distributionally regressive approach to animal disease control in Kenya.Demand and Price Analysis, Livestock Production/Industries,

Proteoglycan degradation by the ADAMTS family of proteinases

AbstractProteoglycans are key components of extracellular matrices, providing structural support as well as influencing cellular behaviour in physiological and pathological processes. The diversity of proteoglycan function reported in the literature is equally matched by diversity in proteoglycan structure. Members of the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) family of enzymes degrade proteoglycans and thereby have the potential to alter tissue architecture and regulate cellular function. In this review, we focus on ADAMTS enzymes that degrade the lectican and small leucine-rich repeat families of proteoglycans. We discuss the known ADAMTS cleavage sites and the consequences of cleavage at these sites. We illustrate our discussion with examples from the literature in which ADAMTS proteolysis of proteoglycans makes profound changes to tissue function

Challenging Orthodoxies: Understanding Poverty in Pastoral Areas of East Africa

Understanding and alleviating poverty in Africa continues to receive considerable attention by a range of diverse actors, including politicians, international celebrities, academics, activists, and practitioners. Despite the onslaught of interest, there surprisingly is little agreement on what constitutes poverty in rural Africa, how it should be assessed, and what should be done to alleviate it. Based on data from an interdisciplinary study of pastoralism in northern Kenya, this article examines issues of poverty among one of the continents most vulnerable groups, pastoralists, and challenges the application of such orthodox proxies as incomes/expenditures, geographic remoteness, and market integration. It argues that current poverty debates homogenize the concept of pastoralist by failing to acknowledge the diverse livelihoods and wealth differentiation that fall under the term. The article concludes that what is not needed is another development label (stereotype) that equates pastoralism with poverty, thereby empowering outside interests to transform rather than strengthen pastoral livelihoods

Assessing the value of climate forecast information for pastoralists: Evidence from southern Ethiopia and northern Kenya

Climatic variability exerts tremendous influence on the livelihoods and well-being of pastoralists who inhabit the arid and semi-arid lands of the Horn of Africa. Recent advances in climate forecasting technologies have raised the intriguing prospect of reasonably accurate forecasts of coming seasons' rainfall patterns. Several donors and governments in the region are keenly interested in these technologies and in developing forecast delivery channels on the assumption that this information will prove valuable to the vulnerable populations it is meant to help not only indirectly, as an input into top-down early warning systems, but also directly, as a basis for improving choice under uncertainty. We explore the value of such external climate forecast information to pastoralists in a large study area spanning southern Ethiopia and northern Kenya using original data collected using both open-ended qualitative methods to identify and understand indigenous climate forecasting methods and quantitative data collected using survey instruments fielded in two rounds, one before and one after the long rains of 2001. The data show that pastoralists rely heavily on indigenous forecasting methods — in terms of having both access to and confidence in these methods — while external forecasts are less commonly received or believed. We elicited pastoralists' subjective, probabilistic expectations of the coming season's rainfall and find that neither use of nor belief in external forecasts causes any appreciable change in respondents' seasonal rainfall expectations. Moreover, relatively few pastoralists act on their own climate expectations, no matter how formed. In sum, climate forecast information does not seem a limiting factor at present in pastoralist communities in the Horn of Africa, not least of which because of the existence of a vibrant and still-relevant tradition of indigenous forecasting

The CS sulphation motifs 4C3, 7D4, 3B3[-]; and perlecan identify stem cell populations and niches, activated progenitor cells and transitional tissue development in the fetal human elbow

We compared the immunohistochemical distribution of (i) the novel chondroitin sulphate (CS) sulphation motifs 7D4, 4C3 and 3B3[-], (ii) native heparan sulphate (HS) and Δ-HS ‘stubs’ generated by heparitinase III digestion and (iii) the HS-proteoglycan, perlecan, in the foetal human elbow joint. Putative stem cell populations associated with hair bulbs, humeral perichondrium, humeral and ulnar rudiment stromal/perivascular tissues expressed the CS motifs 4C3, 7D4 and 3B3[-] as well as perlecan in close association but not co-localised. Chondrocytes in the presumptive articular cartilage of the foetal elbow expressed the 4C3 and 7D4 CS sulphation motifs consistent with earlier studies on the expression of these motifs in knee cartilage following joint cavitation. The present study also indicated that hair bulbs, skin, perichondrium and rudiment stroma were all perlecan rich progenitor cell niches that contributed to the organisation and development of the human foetal elbow joint and associated connective tissues. One of the difficulties in determining the precise role of stem cells in tissue development and repair processes is their short engraftment period and the lack of specific markers which differentiate the activated stem cell lineages from the resident cells. The CS sulphation motifs 7D4, 4C3 and 3B3[-] decorate cell surface proteoglycans on activated stem/progenitor cells and thus can be used to identify these cells in transitional areas of tissue development and in repair tissues and may be applicable to determining a more precise mode of action of stem cells in these processes. Isolation of perlecan from 12-14 week gestational age foetal knee rudiments demonstrated that perlecan in these foetal tissues was a HS-CS hybrid proteoglyca

Pastoralist Livestock Marketing Behavior in Northern Kenya and Southern Ethiopia: An Analysis of Constraints Limiting Off-take Rates

Pastoralists in East Africa\u27s arid and semi-arid lands (ASAL) regularly confront climatic shocks that plunge them into massive herd die-offs and loss of scarce wealth. One of the most puzzling features of pastoralist behavior in times of stress has been their relatively low and non-responsive rate of marketed off-take of animals when faced with likely losses to herd mortality. As Figure 1, from Desta (1999), finds in 17-year herd history data from Borana pastoralists in southern Ethiopia, mortality always exceeds net sales as a share of beginning period herd size, with the latter never exceeding three percent and moving hardly at all in response to shocks to rangeland carrying capacity that cause regular spikes in mortality rates. This case might be more pronounced than others, but the basic pattern is widely believed representative of herd dynamics and marketing patterns among east African ASAL pastoralists

Challenging the Perceptions of Human Tendon Allografts: Influence of Donor Age, Sex, Height, and Tendon on Biomechanical Properties

Background: The use of allograft tendons has increased for primary and revision anterior cruciate ligament reconstruction, but allograft supply is currently limited to a narrow range of tendons and donors up to the age of 65 years. Expanding the range of donors and tendons could help offset an increasing clinical demand. Purpose: To investigate the effects of donor age, sex, height, and specific tendon on the mechanical properties of a range of human lower leg tendons. Study Design: Descriptive laboratory study. Methods: Nine tendons were retrieved from 39 fresh-frozen human cadaveric lower legs (35 donors [13 female, 22 male]; age, 49-99 years; height, 57-85 inches [145-216 cm]) including: Achilles tendon, tibialis posterior and anterior, fibularis longus and brevis, flexor and extensor hallucis longus, plantaris, and flexor digitorum longus. Tendons underwent tensile loading to failure measuring cross-sectional area (CSA), maximum load, strain at failure, ultimate tensile strength, and elastic modulus. Results from 332 tendons were analyzed using mixed-effects linear regression, accounting for donor age, sex, height, and weight. Results: Mechanical properties were significantly different among tendons and were substantially greater than the effects of donor characteristics. Significant effects of donor sex, age, and height were limited to specific tendons: Achilles tendon, tibialis posterior, and tibialis anterior. All other tendons were unaffected. The Achilles tendon was most influenced by donor variables: greater CSA in men (β = 15.45 mm2; Šidák adjusted P < .0001), decreased maximum load with each year of increased age (β = −17.20 N per year; adjusted P = .0253), and increased CSA (β = 1.92 mm2 per inch; adjusted P < .0001) and maximum load (β = 86.40 N per inch; adjusted P < .0001) with each inch of increased height. Conclusion: Mechanical properties vary significantly across different human tendons. The effects of donor age, sex, and height are relatively small, are limited to specific tendons, and affect different tendons uniquely. The findings indicate that age negatively affected only the Achilles tendon (maximum load) and challenge the exclusion of donors aged >65 years across all tendon grafts. Clinical Relevance: The findings support including a broader range of tendons for use as allografts for anterior cruciate ligament reconstruction and reviewing the current exclusion criterion of donors aged >65 years

Fragmentation of decorin, biglycan, lumican and keratocan is elevated in degenerate human meniscus, knee and hip articular cartilages compared with age-matched macroscopically normal and control tissues

Introduction: The small leucine-rich proteoglycans (SLRPs) modulate tissue organization, cellular proliferation, matrix adhesion, growth factor and cytokine responses, and sterically protect the surface of collagen type I and II fibrils from proteolysis. Catabolism of SLRPs has important consequences for the integrity of articular cartilage and meniscus by interfering with their tissue homeostatic functions. Methods: SLRPs were dissociatively extracted from articular cartilage from total knee and hip replacements, menisci from total knee replacements, macroscopically normal and fibrillated knee articular cartilage from mature age-matched donors, and normal young articular cartilage. The tissue extracts were digested with chondroitinase ABC and keratanase-I before identification of SLRP core protein species by Western blotting using antibodies to the carboxyl-termini of the SLRPs. Results: Multiple core-protein species were detected for all of the SLRPs (except fibromodulin) in the degenerate osteoarthritic articular cartilage and menisci. Fibromodulin had markedly less fragments detected with the carboxyl-terminal antibody compared with other SLRPs. There were fewer SLRP catabolites in osteoarthritic hip than in knee articular cartilage. Fragmentation of all SLRPs in normal age-matched, nonfibrillated knee articular cartilage was less than in fibrillated articular cartilage from the same knee joint or total knee replacement articular cartilage specimens of similar age. There was little fragmentation of SLRPs in normal control knee articular cartilage. Only decorin exhibited a consistent increase in fragmentation in menisci in association with osteoarthritis. There were no fragments of decorin, biglycan, lumican, or keratocan that were unique to any tissue. A single fibromodulin fragment was detected in osteoarthritic articular cartilage but not meniscus. All SLRPs showed a modest age-related increase in fragmentation in knee articular and meniscal cartilage but not in other tissues. Conclusion: Enhanced fragmentation of SLRPs is evident in degenerate articular cartilage and meniscus. Specific decorin and fibromodulin core protein fragments in degenerate meniscus and/or human articular cartilage may be of value as biomarkers of disease. Once the enzymes responsible for their generation have been identified, further research may identify them as therapeutic targets

Early allogeneic immune modulation after establishment of donor hematopoietic cell-induced mixed chimerism in a nonhuman primate kidney transplant model

BackgroundMixed lymphohematopoietic chimerism is a proven strategy for achieving operational transplant tolerance, though the underlying immunologic mechanisms are incompletely understood.MethodsA post-transplant, non-myeloablative, tomotherapy-based total lymphoid (TLI) irradiation protocol combined with anti-thymocyte globulin and T cell co-stimulatory blockade (belatacept) induction was applied to a 3-5 MHC antigen mismatched rhesus macaque kidney and hematopoietic cell transplant model. Mechanistic investigations of early (60 days post-transplant) allogeneic immune modulation induced by mixed chimerism were conducted.ResultsChimeric animals demonstrated expansion of circulating and graft-infiltrating CD4+CD25+Foxp3+ regulatory T cells (Tregs), as well as increased differentiation of allo-protective CD8+ T cell phenotypes compared to naïve and non-chimeric animals. In vitro mixed lymphocyte reaction (MLR) responses and donor-specific antibody production were suppressed in animals with mixed chimerism. PD-1 upregulation was observed among CD8+ T effector memory (CD28-CD95+) subsets in chimeric hosts only. PD-1 blockade in donor-specific functional assays augmented MLR and cytotoxic responses and was associated with increased intracellular granzyme B and extracellular IFN-γ production.ConclusionsThese studies demonstrated that donor immune cell engraftment was associated with early immunomodulation via mechanisms of homeostatic expansion of Tregs and early PD-1 upregulation among CD8+ T effector memory cells. These responses may contribute to TLI-based mixed chimerism-induced allogenic tolerance