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1.
Vaccine ; 40(46): 6631-6639, 2022 11 02.
Article in English | MEDLINE | ID: mdl-36210251

ABSTRACT

Rotavirus vaccination has been shown to reduce rotavirus burden in many countries, but the long-term magnitude of vaccine impacts is unclear, particularly in low-income countries. We use a transmission model to estimate the long-term impact of rotavirus vaccination on deaths and disability adjusted life years (DALYs) from 2006 to 2034 for 112 low- and middle-income countries. We also explore the predicted effectiveness of a one- vs two- dose series and the relative contribution of direct vs indirect effects to overall impacts. To validate the model, we compare predicted percent reductions in severe rotavirus cases with the percent reduction in rotavirus positivity among gastroenteritis hospital admissions for 10 countries with pre- and post-vaccine introduction data. We estimate that vaccination would reduce deaths from rotavirus by 49.1 % (95 % UI: 46.6-54.3 %) by 2034 under realistic coverage scenarios, compared to a scenario without vaccination. Most of this benefit is due to direct benefit to vaccinated individuals (explaining 69-97 % of the overall impact), but indirect protection also appears to enhance impacts. We find that a one-dose schedule would only be about 57 % as effective as a two-dose schedule 12 years after vaccine introduction. Our model closely reproduced observed reductions in rotavirus positivity in the first few years after vaccine introduction in select countries. Rotavirus vaccination is likely to have a substantial impact on rotavirus gastroenteritis and its mortality burden. To sustain this benefit, the complete series of doses is needed.


Subject(s)
Gastroenteritis , Rotavirus Infections , Rotavirus Vaccines , Rotavirus , Humans , Infant , Rotavirus Infections/prevention & control , Gastroenteritis/prevention & control , Vaccination , Cost-Benefit Analysis
2.
J R Soc Interface ; 19(194): 20220477, 2022 09.
Article in English | MEDLINE | ID: mdl-36067790

ABSTRACT

Periodic resurgences of COVID-19 in the coming years can be expected, while public health interventions may be able to reduce their intensity. We used a transmission model to assess how the use of booster doses and non-pharmaceutical interventions (NPIs) amid ongoing pathogen evolution might influence future transmission waves. We find that incidence is likely to increase as NPIs relax, with a second seasonally driven surge expected in autumn 2022. However, booster doses can greatly reduce the intensity of both waves and reduce cumulative deaths by 20% between 7 January 2022 and 7 January 2023. Reintroducing NPIs during the autumn as incidence begins to increase again could also be impactful. Combining boosters and NPIs results in a 30% decrease in cumulative deaths, with potential for greater impacts if variant-adapted boosters are used. Reintroducing these NPIs in autumn 2022 as transmission rates increase provides similar benefits to sustaining NPIs indefinitely (307 000 deaths with indefinite NPIs and boosters compared with 304 000 deaths with transient NPIs and boosters). If novel variants with increased transmissibility or immune escape emerge, deaths will be higher, but vaccination and NPIs are expected to remain effective tools to decrease both cumulative and peak health system burden, providing proportionally similar relative impacts.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/epidemiology , COVID-19/prevention & control , Humans , Public Health , Seasons , Vaccination
3.
BMC Public Health ; 20(1): 759, 2020 May 24.
Article in English | MEDLINE | ID: mdl-32448276

ABSTRACT

BACKGROUND: Oshikhandass is a rural village in northern Pakistan where a 1989-1991 verbal autopsy study showed that diarrhea and pneumonia were the top causes of under-5 mortality. Intensive surveillance, active community health education and child health interventions were delivered in 1989-1996; here we assess improvements in under-5 mortality, diarrhea, and pneumonia over this period and 15 years later. METHODS: Two prospective open-cohort studies in Oshikhandass from 1989 to 1996 (Study 1) and 2011-2014 (Study 2) enrolled all children under age 60 months. Study staff trained using WHO guidelines, conducted weekly household surveillance and promoted knowledge on causes and management of diarrhea and pneumonia. Information about household characteristics and socioeconomic status was collected. Hurdle models were constructed to examine putative risk factors for diarrhea and pneumonia. RESULTS: Against a backdrop of considerable change in the socioeconomic status of the community, under-5 mortality, which declined over the course of Study 1 (from 114.3 to 79.5 deaths/1000 live births (LB) between 1989 and 1996), exceeded Sustainable Development Goal 3 by Study 2 (19.8 deaths/ 1000 LB). Reductions in diarrhea prevalence (20.3 to 2.2 days/ Child Year [CY]), incidence (2.1 to 0.5 episodes/ CY), and number of bloody diarrhea episodes (18.6 to 5.2%) seen during Study 1, were sustained in Study 2. Pneumonia incidence was 0.5 episodes /CY in Study 1 and 0.2/CY in Study 2; only 5% of episodes were categorized as severe or very severe in both studies. While no individual factors predicted a statistically significant difference in diarrhea or pneumonia episodes, the combined effect of water, toilet and housing materials was associated with a significant decrease in diarrhea; higher household income was the most protective factor for pneumonia in Study 1. CONCLUSIONS: We report a 4-fold decrease in overall childhood mortality, and a 2-fold decrease in childhood morbidity from diarrhea and pneumonia in a remote rural village in Pakistan between 1989 and 2014. We conclude that significant, sustainable improvements in child health may be achieved through improved socioeconomic status and promoting interactions between locally engaged health workers and the community, but that continued efforts are needed to improve health worker training, supervision, and the rational use of medications. TRIAL REGISTRATION: Not Applicable.


Subject(s)
Diarrhea/mortality , Mortality/trends , Pneumonia/mortality , Child, Preschool , Female , Humans , Incidence , Infant , Longitudinal Studies , Male , Pakistan/epidemiology , Population Surveillance/methods , Prospective Studies , Risk Factors , Rural Population , Social Class
4.
Sci Rep ; 9(1): 16184, 2019 11 07.
Article in English | MEDLINE | ID: mdl-31700095

ABSTRACT

In adults, interoception - the sense of the physiological condition of the body - appears to influence emotion processing, cognition, behavior and various somatic and mental health disorders. Adults demonstrate frontal-insula-parietal-anterior cingulate cortex activation during the heartbeat detection task, a common interoceptive measure. Little, however, is known about the functional neuroanatomy underlying interoception in children. The current pilot study examined interoceptive processing in children and adolescents with fMRI while using the heartbeat detection task. Our main findings demonstrate that children as young as the age of six activate the left insula, cuneus, inferior parietal lobule and prefrontal regions. These findings are similar to those in adults when comparing heartbeat and tone detection conditions. Age was associated with increased activation within the dACC, orbital frontal cortex and the mid-inferior frontal gyri. Thus, our pilot study may provide important information about the neurodevelopment of interoceptive processing abilities in children and a task for future interoception neuroimaging studies in children.


Subject(s)
Cerebral Cortex/diagnostic imaging , Interoception/physiology , Magnetic Resonance Imaging , Adolescent , Adult , Brain Mapping , Child , Female , Humans , Male , Pilot Projects
5.
J Environ Qual ; 47(6): 1412-1425, 2018 11.
Article in English | MEDLINE | ID: mdl-30512071

ABSTRACT

Agriculture in the United States must respond to escalating demands for productivity and efficiency, as well as pressures to improve its stewardship of natural resources. Growing global population and changing diets, combined with a greater societal awareness of agriculture's role in delivering ecosystem services beyond food, feed, fiber, and energy production, require a comprehensive perspective on where and how US agriculture can be sustainably intensified, that is, made more productive without exacerbating local and off-site environmental concerns. The USDA's Long-Term Agroecosystem Research (LTAR) network is composed of 18 locations distributed across the contiguous United States working together to integrate national and local agricultural priorities and advance the sustainable intensification of US agriculture. We explore here the concept of sustainable intensification as a framework for defining strategies to enhance production, environmental, and rural prosperity outcomes from agricultural systems. We also elucidate the diversity of factors that have shaped the past and present conditions of cropland, rangeland, and pastureland agroecosystems represented by the LTAR network and identify priorities for research in the areas of production, resource conservation and environmental quality, and rural prosperity. Ultimately, integrated long-term research on sustainable intensification at the national scale is critical to developing practices and programs that can anticipate and address challenges before they become crises.


Subject(s)
Agriculture/methods , Conservation of Natural Resources/methods , Ecosystem , Food Supply , Research , United States
6.
J Dairy Sci ; 101(7): 6632-6641, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29705411

ABSTRACT

Nutrient management on US dairy farms must balance an array of priorities, some of which conflict. To illustrate nutrient management challenges and opportunities across the US dairy industry, the USDA Agricultural Research Service Dairy Agroecosystems Working Group (DAWG) modeled 8 confinement and 2 grazing operations in the 7 largest US dairy-producing states using the Integrated Farm System Model (IFSM). Opportunities existed across all of the dairies studied to increase on-farm feed production and lower purchased feed bills, most notably on large dairies (>1,000 cows) with the highest herd densities. Purchased feed accounted for 18 to 44% of large dairies' total operating costs compared with 7 to 14% on small dairies (<300 milk cows) due to lower stocking rates. For dairies with larger land bases, in addition to a reduction in environmental impact, financial incentives exist to promote prudent nutrient management practices by substituting manure nutrients or legume nutrients for purchased fertilizers. Environmental priorities varied regionally and were principally tied to facility management for dry-lot dairies of the semi-arid western United States (ammonia-N emissions), to manure handling and application for humid midwestern and eastern US dairies (nitrate-N leaching and P runoff), and pasture management for dairies with significant grazing components (nitrous oxide emissions). Many of the nutrient management challenges identified by DAWG are beyond slight modifications in management and require coordinated solutions to ensure an environmentally and economically sustainable US dairy industry.


Subject(s)
Animal Feed/standards , Animal Nutritional Physiological Phenomena , Cattle/physiology , Dairying/methods , Animals , Female , Manure , Nutritional Requirements , Phosphorus , United States , United States Department of Agriculture
7.
Sci Total Environ ; 572: 442-449, 2016 Dec 01.
Article in English | MEDLINE | ID: mdl-27543947

ABSTRACT

Anthropogenic emissions of nitrous oxide (N2O), a trace gas with severe environmental costs, are greatest from agricultural soils amended with nitrogen (N) fertilizer. However, accurate N2O emission estimates at fine spatial scales are made difficult by their high variability, which represents a critical challenge for the management of N2O emissions. Here, static chamber measurements (n=60) and soil samples (n=129) were collected at approximately weekly intervals (n=6) for 42-d immediately following the application of N in a southern Minnesota cornfield (15.6-ha), typical of the systems prevalent throughout the U.S. Corn Belt. These data were integrated into a geostatistical model that resolved N2O emissions at a high spatial resolution (1-m). Field-scale N2O emissions exhibited a high degree of spatial variability, and were partitioned into three classes of emission strength: hotspots, intermediate, and coldspots. Rates of emission from hotspots were 2-fold greater than non-hotspot locations. Consequently, 36% of the field-scale emissions could be attributed to hotspots, despite representing only 21% of the total field area. Variations in elevation caused hotspots to develop in predictable locations, which were prone to nutrient and moisture accumulation caused by terrain focusing. Because these features are relatively static, our data and analyses indicate that targeted management of hotspots could efficiently reduce field-scale emissions by as much 17%, a significant benefit considering the deleterious effects of atmospheric N2O.


Subject(s)
Air Pollutants/analysis , Air Pollution/prevention & control , Crops, Agricultural/metabolism , Environmental Monitoring/methods , Nitrous Oxide/analysis , Agriculture , Minnesota , Models, Theoretical , Zea mays/metabolism
8.
Anal Chim Acta ; 801: 22-33, 2013 Nov 01.
Article in English | MEDLINE | ID: mdl-24139571

ABSTRACT

Real-world applications will inevitably entail divergence between samples on which chemometric classifiers are trained and the unknowns requiring classification. This has long been recognized, but there is a shortage of empirical studies on which classifiers perform best in 'external validation' (EV), where the unknown samples are subject to sources of variation relative to the population used to train the classifier. Survey of 286 classification studies in analytical chemistry found only 6.6% that stated elements of variance between training and test samples. Instead, most tested classifiers using hold-outs or resampling (usually cross-validation) from the same population used in training. The present study evaluated a wide range of classifiers on NMR and mass spectra of plant and food materials, from four projects with different data properties (e.g., different numbers and prevalence of classes) and classification objectives. Use of cross-validation was found to be optimistic relative to EV on samples of different provenance to the training set (e.g., different genotypes, different growth conditions, different seasons of crop harvest). For classifier evaluations across the diverse tasks, we used ranks-based non-parametric comparisons, and permutation-based significance tests. Although latent variable methods (e.g., PLSDA) were used in 64% of the surveyed papers, they were among the less successful classifiers in EV, and orthogonal signal correction was counterproductive. Instead, the best EV performances were obtained with machine learning schemes that coped with the high dimensionality (914-1898 features). Random forests confirmed their resilience to high dimensionality, as best overall performers on the full data, despite being used in only 4.5% of the surveyed papers. Most other machine learning classifiers were improved by a feature selection filter (ReliefF), but still did not out-perform random forests.


Subject(s)
Magnetic Resonance Spectroscopy , Mass Spectrometry , Algorithms , Arabidopsis/chemistry , Arabidopsis/classification , Arabidopsis/genetics , Arabidopsis/metabolism , Biomass , Cacao/chemistry , Cacao/classification , Cacao/genetics , Cacao/metabolism , Discriminant Analysis , Metabolomics , Reproducibility of Results , Salicylic Acid/metabolism
9.
FASEB J ; 25(12): 4348-57, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21868472

ABSTRACT

Endurance exercise is a poorly defined yet powerful mediator of hematopoiesis. The purpose of this study was to directly investigate the effects of endurance exercise training on hematopoiesis and to identify potential mechanisms responsible for any observed changes. Four-week-old male C57Bl/6 mice were trained on a treadmill at progressive speeds over a 10-wk period. Tissues were harvested 2 d following the final training session. Flow cytometry, the cobblestone area-forming cell assay, and the methycellulose colony-forming unit assay were used to assess medullary and mobilized hematopoietic stem and progenitor cells. Quantitative real-time PCR and Western blots were used to measure hematopoietic cytokine production. Histochemistry was also used to assess adaptations to exercise in the bone marrow niche. Depending on the cell type, endurance training increased medullary and mobilized hematopoietic stem and progenitor cell content from 50 to 800%. Training also reduced marrow cavity fat by 78%. Skeletal muscle hematopoietic cytokine expression was also increased at least 60% by training. Sedentary mice served as controls for the above experiments. In conclusion, endurance exercise training greatly promotes hematopoiesis and does so through improvements in medullary niche architecture as well as increased skeletal muscle hematopoietic cytokine production.


Subject(s)
Hematopoiesis/physiology , Physical Conditioning, Animal/physiology , Physical Endurance/physiology , Animals , Cell Differentiation , Cytokines/biosynthesis , Cytokines/genetics , Erythropoietin/biosynthesis , Erythropoietin/genetics , Gene Expression , Hematopoietic Stem Cells/cytology , Kidney/physiology , Male , Mesenchymal Stem Cells/cytology , Mice , Mice, Inbred C57BL , Muscle, Skeletal/physiology
10.
Chemosphere ; 77(4): 574-81, 2009 Oct.
Article in English | MEDLINE | ID: mdl-19647284

ABSTRACT

A potential abatement to increasing levels of carbon dioxide (CO(2)) in the atmosphere is the use of pyrolysis to convert vegetative biomass into a more stable form of carbon (biochar) that could then be applied to the soil. However, the impacts of pyrolysis biochar on the soil system need to be assessed before initiating large scale biochar applications to agricultural fields. We compared CO(2) respiration, nitrous oxide (N(2)O) production, methane (CH(4)) oxidation and herbicide retention and transformation through laboratory incubations at field capacity in a Minnesota soil (Waukegan silt loam) with and without added biochar. CO(2) originating from the biochar needs to be subtracted from the soil-biochar combination in order to elucidate the impact of biochar on soil respiration. After this correction, biochar amendments reduced CO(2) production for all amendment levels tested (2, 5, 10, 20, 40 and 60% w/w; corresponding to 24-720 tha(-1) field application rates). In addition, biochar additions suppressed N(2)O production at all levels. However, these reductions were only significant at biochar amendment levels >20% w/w. Biochar additions also significantly suppressed ambient CH(4) oxidation at all levels compared to unamended soil. The addition of biochar (5% w/w) to soil increased the sorption of atrazine and acetochlor compared to non-amended soils, resulting in decreased dissipation rates of these herbicides. The recalcitrance of the biochar suggests that it could be a viable carbon sequestration strategy, and might provide substantial net greenhouse gas benefits if the reductions in N(2)O production are lasting.


Subject(s)
Charcoal/chemistry , Gases/chemistry , Herbicides/metabolism , Soil Pollutants/metabolism , Adsorption , Atrazine/chemistry , Atrazine/metabolism , Carbon Dioxide/chemistry , Environmental Monitoring , Greenhouse Effect , Herbicides/chemistry , Methane/chemistry , Minnesota , Nitrous Oxide/chemistry , Oxidation-Reduction , Soil , Soil Pollutants/chemistry , Toluidines/chemistry , Toluidines/metabolism
11.
J Phys Condens Matter ; 21(36): 364212, 2009 Sep 09.
Article in English | MEDLINE | ID: mdl-21832318

ABSTRACT

We report on electron paramagnetic resonance (EPR) studies of nitrogen doped diamond that has been (15)N enriched, electron irradiated and annealed. EPR spectra from two new nitrogen containing [Formula: see text] defects are detected and labelled WAR9 and WAR10. We show that the properties of these defects are consistent with them being the ⟨001⟩-nitrogen split interstitial and the ⟨001⟩-nitrogen split interstitial-⟨001⟩-carbon split interstitial pair, respectively. We also provide an explanation for why these defects have previously eluded discovery.

12.
J Cosmet Sci ; 58(6): 637-50, 2007.
Article in English | MEDLINE | ID: mdl-18305877

ABSTRACT

There is a continuing need for hair care formulas to deliver superior conditioning benefits with highly efficient deposition of hair-enhancing components. In this paper, we describe high-charge-density (3.0 mEq/g) cassia hydroxypropyltrimonium chloride (cassia HPTC), a quaternized galactomannan from the endosperm of Cassia tora and Cassia obtusifolia. Cassia HPTC is shown to participate in the coacervate phase of conditioning shampoos, from which it is deposited onto hair to provide conditioning benefits. Cryo-scanning electron microscopy and time-of-flight secondary ion mass spectrometry were used to observe and characterize the cassia HPTC deposits left on hair. The high-charge-density cassia HPTC resulted in improved deposition efficiency compared with a quaternized guar-containing formula. Cassia HPTC offers benefits as an alternative to traditional cationic polymers as conditioning agents or as an adjunct conditioner to decrease the amount of cationic polymer needed to achieve the desired conditioning performance.


Subject(s)
Cassia/chemistry , Hair Preparations/chemistry , Hair/chemistry , Mannans/chemistry , Galactose/analogs & derivatives , Hair/ultrastructure , Humans , Microscopy, Electron, Scanning , Microscopy, Interference , Spectrometry, Mass, Secondary Ion
13.
Exp Neurol ; 199(2): 348-53, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16487516

ABSTRACT

The purpose of this study was to evaluate the effect of continuously released BDNF on peripheral nerve regeneration in a rat model. Initial in vitro evaluation of calcium alginate prolonged-release-capsules (PRC) proved a consistent release of BDNF for a minimum of 8 weeks. In vivo, a worst case scenario was created by surgical removal of a 20-mm section of the sciatic nerve of the rat. Twenty-four autologous fascia tubes were filled with calcium alginate spheres and sutured to the epineurium of both nerve ends. The animals were divided into 3 groups. In group 1, the fascial tube contained plain calcium alginate spheres. In groups 2 and 3, the fascial tube contained calcium alginate spheres with BDNF alone or BDNF stabilized with bovine serum albumin, respectively. The autocannibalization of the operated extremity was clinically assessed and documented in 12 additional rats. The regeneration was evaluated histologically at 4 weeks and 10 weeks in a blinded manner. The length of nerve fibers and the numbers of axons formed in the tube was measured. Over a 10-week period, axons have grown significantly faster in groups 2 and 3 with continuously released BDNF compared to the control. The rats treated with BDNF (groups 2 and 3) demonstrated significantly less autocannibalization than the control group (group 1). These results suggest that BDNF may not only stimulate faster peripheral nerve regeneration provided there is an ideal, biodegradable continuous delivery system but that it significantly reduces the neuropathic pain in the rat model.


Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Nerve Regeneration/physiology , Peripheral Nervous System Diseases/metabolism , Animals , Disease Models, Animal , Female , In Vitro Techniques , Peripheral Nervous System Diseases/physiopathology , Rats , Rats, Sprague-Dawley , Spectrometry, Fluorescence/methods , Time Factors
14.
Phys Rev Lett ; 90(18): 185507, 2003 May 09.
Article in English | MEDLINE | ID: mdl-12786024

ABSTRACT

We report the identification of the nitrogen-vacancy-hydrogen complex in a freestanding nitrogen-doped isotopically engineered single crystal diamond synthesized by chemical vapor deposition. The hydrogen atom is located in the vacancy of a nearest-neighbor nitrogen-vacancy defect and appears to be bonded to the nitrogen atom maintaining the trigonal symmetry of the center. The defect is observed by electron paramagnetic resonance in the negative charge state in samples containing a suitable electron donor (e.g., substitutional nitrogen N(0)(S)).

15.
Contraception ; 66(5): 369-75, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12443969

ABSTRACT

Genital irritation and user acceptability was compared after seven nightly bedtime exposures to 1.2% C31G hydroxyethyl cellulose (HEC), 2% nonoxynol-9 (N-9) (Gynol II) or HEC vehicle alone. Sixty healthy women over 18 years old at low risk for sexually transmitted disease with normal menses were randomly assigned to one of three groups. Entrance and exit pelvic exams documented vaginal pH and Gram stain. Genital irritation was assessed by patient diaries, a telephone call 24 to 48 h after first use, colposcopy done the day after last product use, and an acceptability questionnaire at exit. Eighty percent of the women using C31G HEC experienced symptoms of vaginal burning or heat compared to 25% of the N-9 users and 5% of the vehicle users. Colposcopic findings were similar for the active treatments of C31G HEC and N-9: 50% vs. 60% developed new lesions, 25% vs. 20% had lesions that disrupted epithelial integrity, and 50% vs. 45% had minor lesions, respectively. Findings with the HEC vehicle were half as frequent. Twelve percent of women had epithelial disruption that was assessed by the colposcopist as applicator-related. Gram stains were half as likely to show bacterial vaginosis after N-9 use (6 --> 3) and one fourth as likely after vehicle or C31G HEC use (4 --> 1). When asked if they would use the product if it were an effective contraceptive, 55% of the vehicle users, 35% of the N-9 users, and 25% of the C31G HEC users agreed. Product acceptability of C31G HEC was limited by the sensation of heat or burning. The C31G HEC product had a similar safety profile to N-9 in this comparative trial.


Subject(s)
Anti-Infective Agents/therapeutic use , Betaine/analogs & derivatives , Betaine/therapeutic use , Fatty Acids, Unsaturated/therapeutic use , Sexually Transmitted Diseases/prevention & control , Administration, Intravaginal , Adult , Anti-Infective Agents/administration & dosage , Anti-Infective Agents/adverse effects , Betaine/administration & dosage , Betaine/adverse effects , Cellulose , Colposcopy , Double-Blind Method , England , Fatty Acids, Unsaturated/administration & dosage , Fatty Acids, Unsaturated/adverse effects , Female , Gels , Humans , North Carolina , Patient Satisfaction , Pennsylvania , Surveys and Questionnaires , Treatment Outcome , Vagina/drug effects , Vagina/pathology
16.
Plast Reconstr Surg ; 109(1): 190-8, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11786811

ABSTRACT

The purpose of this pilot study was to prefabricate a vascularized bone graft by using a vascularized periosteal flap containing osteoprogenitor cells, a structural matrix, and recombinant human bone morphogenetic protein-2 (rhBMP-2). In a rat model, a periosteal flap vascularized by the saphenous artery and vein was dissected off the medial surface of the tibia. This flap consisted of three layers-periosteum, muscle, and fascia-and was tubed on itself to form a watertight chamber that was then transferred on its vascular pedicle to the groin. A total of 78 vascularized periosteal chambers were constructed in 39 animals and divided into 10 groups. In group 1, the periosteal chamber was left empty. Groups 2, 3, and 4 consisted of the periosteal flap and rhBMP-2, but in group 3, the proximal vascular pedicle was ligated, and in group 4, the flap was harvested without the periosteal layer and turned inside out. Groups 5 through 10 consisted of the vascularized periosteal flap containing several different structural matrices (calcium alginate spheres, polylactic acid, or demineralized bone matrix) with or without rhBMP-2. Animals were killed at 2, 4, or 8 weeks in each group. The presence and density of any new bone formation was evaluated both radiologically and histologically. Significant bone formation was seen only in those periosteal flaps containing rhBMP-2 and either the calcium alginate or polylactic acid matrix. New bone formation increased both radiologically and histologically from 2 weeks to 8 weeks only in the periosteal flaps containing the polylactic acid matrix and rhBMP-2. This preliminary study therefore suggests that four factors-blood supply, osteoprogenitor cells in the periosteal layer, a biodegradable matrix, and rhBMP-2-are required for optimal prefabrication of a vascularized bone graft.


Subject(s)
Bone Morphogenetic Proteins/pharmacology , Osteogenesis , Periosteum/transplantation , Surgical Flaps/blood supply , Transforming Growth Factor beta , Alginates , Animals , Biocompatible Materials , Bone Demineralization Technique , Bone Matrix , Bone Morphogenetic Protein 2 , Bone and Bones/cytology , Bone and Bones/diagnostic imaging , Glucuronic Acid , Groin/surgery , Hexuronic Acids , Lactic Acid , Male , Microspheres , Periosteum/blood supply , Pilot Projects , Polyesters , Polymers , Radiography , Rats , Rats, Inbred Lew , Recombinant Proteins/pharmacology , Tibia
17.
Platelets ; 12(6): 333-42, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11672472

ABSTRACT

The intracellular pH of human platelets is affected by external pH and by the addition of metabolic substrates and analogues. Acetate and propionate decrease pH in a rapid concentration-dependent manner, whereas glucose decreases the internal pH at a slower rate which is independent of concentration above 0.3 mM. The mechanisms of these effects is discussed. The rate of metabolism of glucose to lactate in human platelets was strongly pH-dependent, with higher rates at more alkaline pH values. This effect was found for several different buffer systems. Addition of acetate caused an inhibition of glycolysis, whereas addition of propionate had little effect. The rate of the oxidative pentose phosphate pathway also increased with increasing pH and this pathway was inhibited by both acetate and propionate. It is proposed that the effect of acetate on glycolysis required the metabolism of the acetate, whereas the effect of both acetate and propionate on the pentose phosphate pathway are directly due to the decrease in internal pH. The oxidation of acetate to carbon dioxide showed only small pH-dependent changes in rate unless glucose was also present: glucose inhibited oxidative metabolism (the 'Crabtree Effect'), but this inhibition was only apparent at higher pH values when glycolytic rates were high.


Subject(s)
Acetic Acid/metabolism , Blood Platelets/metabolism , Glucose/metabolism , Glycolysis/physiology , Pentose Phosphate Pathway/physiology , Acetic Acid/pharmacology , Extracellular Space/drug effects , Glucose/pharmacology , Glycolysis/drug effects , Humans , Hydrogen-Ion Concentration/drug effects , Intracellular Fluid/drug effects , Oxidation-Reduction , Pentose Phosphate Pathway/drug effects , Propionates/metabolism , Propionates/pharmacology
18.
J Org Chem ; 66(8): 2662-6, 2001 Apr 20.
Article in English | MEDLINE | ID: mdl-11304184

ABSTRACT

The effects of fluorine substitution on the cyclobutylcarbinyl to 4-pentenyl radical rearrangement and on the strain of cyclobutane have being studied using density functional theory, the ring-opening being modestly inhibited and the strain generally not greatly affected. Perfluorocyclobutane is predicted to have 6 kcal/mol less strain than cyclobutane. Cyclizations of 1,1,2,2-tetrafluoro- and 1,1,2,2,3,3-hexafluoro-4-pentenyl radicals should be significantly enhanced ( approximately 2400 times faster) relative to the parent system. The calculations are consistent with the few experimental data available.

19.
Reprod Fertil Dev ; 13(7-8): 635-45, 2001.
Article in English | MEDLINE | ID: mdl-11999315

ABSTRACT

Serological and cellular assays and molecular techniques were used to define features of the major histocompatibility complex (MHC) of the donkey With this information in hand, immune recognition of MHC determinants within and between donkeys and horses was compared. An antibody-mediated, complement-dependent, microcytotoxicity assay using a variety of antisera to donkey histocompatibility antigens, including those induced as a result of intraspecies or interspecies pregnancy in horse mares and jenny donkeys, delineated five donkey leukocyte antigen (DoLA) specificities. Antisera raised across species barriers (horse anti-donkey and donkey anti-horse) recognized polymorphic antigenic determinants in the target species. These determinants were often indistinguishable from polymorphic antigens recognized by alloantisera raised within horses or donkeys. The data indicate that a strong correlation exists between the serological antigenic types identified and the specificity of cytotoxic T lymphocytes raised by lymphocyte co-cultures, either within or between species. Moreover, in an analysis of a small number of donkey MHC class I cDNA gene sequences, no features distinguishing horse or donkey MHC class I molecules were identified. These molecular findings explain in large measure why antibody- and T-cell-defined alloantigen recognition is conserved among these closely related equids.


Subject(s)
Antibody Specificity , Equidae/immunology , Horses/immunology , Isoantigens/immunology , T-Lymphocytes/immunology , Amino Acid Sequence , Animals , Base Sequence , Cytotoxicity Tests, Immunologic , DNA, Complementary/chemistry , Epitopes , Female , Histocompatibility Antigens/genetics , Histocompatibility Antigens/immunology , Histocompatibility Antigens Class I/chemistry , Histocompatibility Antigens Class I/genetics , Immune Sera , Isoantibodies , Isoantigens/analysis , Male , Molecular Sequence Data , Pregnancy , Sequence Analysis, DNA , Species Specificity
20.
Immunogenetics ; 53(9): 802-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11862413

ABSTRACT

Sequence and functional analyses were undertaken on two cDNAs and a genomic clone encoding horse major histocompatibility complex (MHC) class I molecules. All of the clones were isolated from a single horse that is homozygous for all known horse MHC class I and class II antigens. The two cDNAs (clones 8-9 and 1-29) were isolated from a lymphocyte library and encode polymorphic MHC antigens from two loci. The genomic cosmid clone, isolated from a sperm library, contains the 8-9 gene. All three genes were expressed in mouse L-cells and were recognized by alloantisera and, for the cDNAs, by alloreactive cytotoxic T lymphocytes. A total of 3815 bp of the genomic clone were sequenced, extending from 429 bp upstream (5') of the leader peptide through the 3' untranslated region. Promoter region motifs and an intron-exon structure characteristic of MHC class I genes of other species were found. A subclone containing 407 bp of the promoter region was inserted into a chloramphenicol acetyl transferase reporter plasmid, tested in transient transfection assays, and found to have promoter activity in heterologous cells. This genomic clone will enable detailed studies of MHC class I gene regulation in horse trophoblasts, and in horse retroviral infections.


Subject(s)
Genes, MHC Class I , Horses/genetics , Horses/immunology , Amino Acid Sequence , Animals , Base Sequence , Conserved Sequence , DNA, Complementary/genetics , Exons , Histocompatibility Antigens Class I/genetics , In Vitro Techniques , Introns , L Cells , Male , Mice , Molecular Sequence Data , Promoter Regions, Genetic , Sequence Homology, Nucleic Acid , T-Lymphocytes, Cytotoxic/immunology
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