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1.
J Occup Rehabil ; 33(1): 179-188, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-35927599

RESUMO

PURPOSE: Early intervention vocational rehabilitation (EIVR) can improve return to work (RTW) outcomes for people with spinal cord injury (SCI). However, mechanisms explaining how and why EIVR works are not well understood. This study aims to develop a conceptual framework describing key mechanisms of EIVR intervention effect following SCI. METHODS: We synthesised data from a realist literature review with data from interviews of people with SCI (n = 30), a survey of people with SCI who had received EIVR (n = 37), a focus group of EIVR providers and a focus group of community vocational providers. We first synthesised the literature review and interviews to develop an initial programme theory describing the contexts in which mechanisms are activated to produce EIVR outcomes. Then we used data from the survey and focus groups to further refine the EIVR programme theory. Finally, a conceptual framework was developed to support knowledge dissemination. RESULTS: By ensuring consistent messaging across the multi-disciplinary team, EIVR programmes establish and maintain hope that work is possible following injury. Conversations about work allow individuals to determine the priority of work following injury. These conversations can also improve self-efficacy by providing individualized support to envisage pathways toward RTW goals and maintain worker identity. The synthesised study findings highlight the contexts and resources required to trigger activation of these mechanisms. CONCLUSIONS: EIVR key mechanisms of effect are not specific to SCI as a health condition, therefore enabling this framework to be applied to other populations who face similar impairments and return to work barriers.


Assuntos
Reabilitação Vocacional , Traumatismos da Medula Espinal , Humanos , Retorno ao Trabalho , Ocupações , Grupos Focais , Traumatismos da Medula Espinal/reabilitação
3.
Phys Occup Ther Pediatr ; 38(5): 510-526, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29236556

RESUMO

AIM: To develop a model for understanding mechanisms of change in health outcomes for riders with disabilities participating in therapeutic horse riding (THR). METHODS: Using grounded theory methods we collected and analyzed data from interviews with 16 child riders and 18 caregivers, teachers and primary therapists, and from participant-observation during THR sessions. RESULTS: The central concept underpinning the model illustrating mechanisms of change was "gaining the tools to go on." Riders' experiences suggested the THR landscape (i.e., "where the tools are gathered") allowed for an expanded range of experiences in which riders could participate. Riders experienced an expansion of self-concept by learning to move, succeed, connect, and adapt (i.e., "the tools gathered") within the THR landscape. Riders then iteratively translated an expanded view of self into other environments, reflecting "how and where the tools are used." CONCLUSION: Findings suggest that positive changes in health arise from riders' experiences of learning and agency within the THR therapeutic landscape, and from the influence of these experiences on a child's developing self-concept. This article considers the wider impact of THR on children's health, beyond a focus on changes in physical outcomes.


Assuntos
Pessoas com Deficiência/reabilitação , Terapia Assistida por Cavalos/métodos , Adolescente , Criança , Feminino , Teoria Fundamentada , Humanos , Masculino , Nova Zelândia , Autoimagem
4.
J Evol Biol ; 29(11): 2256-2265, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27467980

RESUMO

Sexual signalling is predicted to shape the evolution of sex-specific ornamentation, and establishing the costs and benefits of ornamentation and the information that ornamentation provides to receivers is necessary to evaluating this adaptive function. Here, we assessed the adaptive function of a common colour ornament in insects, melanin wing ornamentation, using the dragonfly Pachydiplax longipennis. We hypothesized that greater ornamentation would improve territory-holding success by decreasing aggression that males receive from territorial rivals, but that more ornamented males may have shorter lifespans. Using mark-recapture field observations, we found that more ornamented males had greater territory-holding success and that viability selection did not act on wing melanization. We then compared the aggression of territorial rivals to decoy males before and after experimentally augmenting wing melanization, finding that males significantly reduced aggression following the manipulation. We next hypothesized that wing melanization would signal fighting ability to territorial rivals by reflecting condition via investment in the costly melanin synthesis pathway. We observed a positive relationship between ornamentation and the likelihood of winning territorial disputes, suggesting that wing melanization provides information about fighting ability to rivals. We also found a positive relationship between melanin-based immune defence and ornamentation, supporting a link between the signal and condition. We conclude that wing melanization is a condition-related signal of fighting ability and suggest that this may be a common mechanism promoting the evolution of melanin ornamentation.


Assuntos
Cor , Melaninas , Odonatos , Territorialidade , Animais , Evolução Biológica , Feminino , Masculino , Asas de Animais
5.
J Evol Biol ; 29(10): 1977-1985, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27316646

RESUMO

Offspring quantity and quality are components of parental fitness that cannot be maximized simultaneously. When the benefits of investing in offspring quality decline, parents are expected to shift investment towards offspring quantity (other reproductive opportunities). Even when mothers retain complete control of resource allocation, offspring control whether to allocate investment to growth or development towards independence, and this shared control may generate parent-offspring conflict over the duration of care. We examined these predictions by, in a captive colony, experimentally removing tadpoles of the strawberry poison frog (Oophaga pumilio) from the mothers that provision them with trophic eggs throughout development. Tadpoles removed from their mothers were no less likely to survive to nutritional independence (i.e. through metamorphosis) than were those that remained with their mothers, but these offspring were smaller at metamorphosis and were less likely to survive to reach adult size, even though they were fed ad libitum. Tadpoles that remained with their mothers developed more slowly than those not receiving care, a pattern that might suggest that offspring extracted more care than was in mothers' best interests. However, the fitness returns of providing care increased with offspring development, suggesting that mothers would be best off continuing care until tadpoles initiated metamorphosis. Although the benefits of parental investment in offspring quality are often thought to asymptote at high levels, driving parent-offspring conflict over weaning, this assumption may not hold over natural ranges of investment, with selection on both parents and offspring favouring extended durations of parental care.


Assuntos
Comportamento Materno , Ranidae , Reprodução , Animais , Anuros , Ovos , Larva , Metamorfose Biológica
7.
J R Soc Interface ; 9(76): 3161-4, 2012 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-22832360

RESUMO

Globally, more than 1000 tonnes of titanium (Ti) is implanted into patients in the form of biomedical devices on an annual basis. Ti is perceived to be 'biocompatible' owing to the presence of a robust passive oxide film (approx. 4 nm thick) at the metal surface. However, surface deterioration can lead to the release of Ti ions, and particles can arise as the result of wear and/or corrosion processes. This surface deterioration can result in peri-implant inflammation, leading to the premature loss of the implanted device or the requirement for surgical revision. Soft tissues surrounding commercially pure cranial anchorage devices (bone-anchored hearing aid) were investigated using synchrotron X-ray micro-fluorescence spectroscopy and X-ray absorption near edge structure. Here, we present the first experimental evidence that minimal load-bearing Ti implants, which are not subjected to macroscopic wear processes, can release Ti debris into the surrounding soft tissue. As such debris has been shown to be pro-inflammatory, we propose that such distributions of Ti are likely to effect to the service life of the device.


Assuntos
Materiais Biocompatíveis/análise , Peri-Implantite/patologia , Próteses e Implantes/efeitos adversos , Titânio/análise , Corrosão , Humanos , Espectrometria por Raios X , Síncrotrons , Espectroscopia por Absorção de Raios X
8.
Philos Trans A Math Phys Eng Sci ; 370(1963): 1422-43, 2012 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-22349249

RESUMO

Bone is the second most widely transplanted tissue after blood. Synthetic alternatives are needed that can reduce the need for transplants and regenerate bone by acting as active temporary templates for bone growth. Bioactive glasses are one of the most promising bone replacement/regeneration materials because they bond to existing bone, are degradable and stimulate new bone growth by the action of their dissolution products on cells. Sol-gel-derived bioactive glasses can be foamed to produce interconnected macropores suitable for tissue ingrowth, particularly cell migration and vascularization and cell penetration. The scaffolds fulfil many of the criteria of an ideal synthetic bone graft, but are not suitable for all bone defect sites because they are brittle. One strategy for improving toughness of the scaffolds without losing their other beneficial properties is to synthesize inorganic/organic hybrids. These hybrids have polymers introduced into the sol-gel process so that the organic and inorganic components interact at the molecular level, providing control over mechanical properties and degradation rates. However, a full understanding of how each feature or property of the glass and hybrid scaffolds affects cellular response is needed to optimize the materials and ensure long-term success and clinical products. This review focuses on the techniques that have been developed for characterizing the hierarchical structures of sol-gel glasses and hybrids, from atomic-scale amorphous networks, through the covalent bonding between components in hybrids and nanoporosity, to quantifying open macroporous networks of the scaffolds. Methods for non-destructive in situ monitoring of degradation and bioactivity mechanisms of the materials are also included.


Assuntos
Regeneração Óssea/fisiologia , Substitutos Ósseos/química , Portadores de Fármacos/química , Vidro/química , Silicatos/química , Alicerces Teciduais , Animais , Humanos , Transição de Fase
9.
Pediatrics ; 124(6): e1228-39, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19901005

RESUMO

Hunter syndrome is a rare, X-linked disorder caused by a deficiency of the lysosomal enzyme iduronate-2-sulfatase. In the absence of sufficient enzyme activity, glycosaminoglycans accumulate in the lysosomes of many tissues and organs and contribute to the multisystem, progressive pathologies seen in Hunter syndrome. The nervous, cardiovascular, respiratory, and musculoskeletal systems can be involved in individuals with Hunter syndrome. Although the management of some clinical problems associated with the disease may seem routine, the management is typically complex and requires the physician to be aware of the special issues surrounding the patient with Hunter syndrome, and a multidisciplinary approach should be taken. Subspecialties such as otorhinolaryngology, neurosurgery, orthopedics, cardiology, anesthesiology, pulmonology, and neurodevelopment will all have a role in management, as will specialty areas such as physiotherapy, audiology, and others. The important management topics are discussed in this review, and the use of enzyme-replacement therapy with recombinant human iduronate-2-sulfatase as a specific treatment for Hunter syndrome is presented.


Assuntos
Comportamento Cooperativo , Terapia de Reposição de Enzimas , Transplante de Células-Tronco Hematopoéticas , Iduronato Sulfatase/efeitos adversos , Comunicação Interdisciplinar , Mucopolissacaridose II/terapia , Equipe de Assistência ao Paciente , Adolescente , Adulto , Criança , Pré-Escolar , Terapia Combinada , Genótipo , Humanos , Lactente , Recém-Nascido , Infusões Intravenosas , Masculino , Mucopolissacaridose II/genética , Fenótipo , Ensaios Clínicos Controlados Aleatórios como Assunto , Proteínas Recombinantes/administração & dosagem , Adulto Jovem
10.
Orthod Craniofac Res ; 12(4): 271-81, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19840279

RESUMO

OBJECTIVE: Various lines of evidence suggest that face shape may be a predisposing factor for non-syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non-cleft) parents of individuals with CL / P and unrelated controls. METHODS: Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. RESULTS: Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL/P. Shape changes associated with CL/P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex-specific pattern of parent-control difference was evident in the transverse dimensions of the nasolabial complex. CONCLUSIONS: The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL/P.


Assuntos
Fenda Labial/genética , Fissura Palatina/genética , Face/anatomia & histologia , Predisposição Genética para Doença , Pais , Estudos de Casos e Controles , Cefalometria , Saúde da Família , Feminino , Humanos , Imageamento Tridimensional , Lábio/anatomia & histologia , Masculino , Desenvolvimento Maxilofacial/genética , Nariz/anatomia & histologia , Órbita/anatomia & histologia , Fotogrametria , Análise de Componente Principal , Fatores Sexuais , Dimensão Vertical , Zigoma/anatomia & histologia
11.
N Z Vet J ; 57(3): 141-5, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19521462

RESUMO

AIM: To determine the effects of annual rainfall and farm on the efficacy of melatonin implants in improving lamb production in Merino sheep in Spain. METHODS: A study was conducted on 3,871 Merino sheep on six farms over a 4-year period (2004-2007). Melatonin implants were inserted during the second half of February or early March (winter) (Melatonin group) or not (Control group). Multinomial logistic regression was used to determine the effects of melatonin, farm and year, and their interactions, on reproductive outcomes. Regression analysis was used to examine the relationship between annual rainfall and the percentage of ewes lambing, percentage of lambs born to ewes lambing, and overall lambing percentage, for each year and treatment group within farm. RESULTS: Annual rainfall, farm and treatment with melatonin, and their interactions, had a significant effect on the reproductive performance of ewes (p<0.001). Treatment with melatonin increased the percentage of ewes lambing (Melatonin group = 77 (SEM 4)%, Control group = 44 (SEM 7)%; p<0.0001), and overall lambing percentage (Melatonin group = 109 (SEM 1)%, Control group = 59 (SEM 2)%; p<0.0001). Treatment differences were especially pronounced in 2005 and 2006, when annual rainfall was exceptionally low; ewes in the Control group had the lowest lambing rates those years. Lambing rates and overall lambing percentage were positively correlated (p<0.05) with the amount of annual rainfall but the correlation coefficients were higher in the Control than Melatonin group. CONCLUSIONS: Melatonin implants are an effective means of improving lamb production of Merino ewes, especially in harsh environments where low annual rainfall limits the availability of food. When melatonin treatment was used, however, the responses of flocks on individual farms were difficult to predict because within a year, responses did not occur on all farms.


Assuntos
Criação de Animais Domésticos/métodos , Estro/efeitos dos fármacos , Melatonina/farmacologia , Reprodução/efeitos dos fármacos , Ovinos/fisiologia , Animais , Estudos de Casos e Controles , Implantes de Medicamento , Feminino , Modelos Logísticos , Masculino , Melatonina/administração & dosagem , Gravidez , Chuva , Espanha
12.
J Biomed Mater Res A ; 91(1): 76-83, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18767060

RESUMO

Recent work has highlighted the potential of sol-gel-derived calcium silicate glasses for the regeneration or replacement of damaged bone tissue. The work presented herein provides new insight into the processing of bioactive calcia-silica sol-gel foams, and the reaction mechanisms associated with them when immersed in vitro in a simulated body fluid (SBF). Small-angle X-ray scattering and wide-angle X-ray scattering (diffraction) have been used to study the stabilization of these foams via heat treatment, with analogous in situ time-resolved data being gathered for a foam immersed in SBF. During thermal processing, pore sizes have been identified in the range of 16.5-62.0 nm and are only present once foams have been heated to 400 degrees C and above. Calcium nitrate crystallites were present until foams were heated to 600 degrees C; the crystallite size varied from 75 to 145 nm and increased in size with heat treatment up to 300 degrees C, then decreased in size down to 95 nm at 400 degrees C. The in situ time-resolved data show that the average pore diameter decreases as a function of immersion time in SBF, as calcium phosphates grow on the glass surfaces. Over the same time, Bragg peaks indicative of tricalcium phosphate were evident after only 1-h immersion time, and later, hydroxycarbonate apatite was also seen. The hydroxycarbonate apatite appears to have preferred orientation in the (h,k,0) direction.


Assuntos
Apatitas/química , Materiais Biocompatíveis/química , Compostos de Cálcio/química , Silicatos/química , Temperatura Alta , Transição de Fase , Porosidade , Espalhamento a Baixo Ângulo , Difração de Raios X
13.
J Mater Sci Mater Med ; 20(4): 883-8, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19083082

RESUMO

Melt quenched silicate glasses containing calcium, phosphorous and alkali metals have the ability to promote bone regeneration and to fuse to living bone. These glasses, including 45S5 Bioglass((R)) [(CaO)(26.9)(Na(2)O)(24.4)(SiO(2))(46.1)(P(2)O(5))(2.6)], are routinely used as clinical implants. Consequently there have been numerous studies on the structure of these glasses using conventional diffraction techniques. These studies have provided important information on the atomic structure of Bioglass((R)) but are of course intrinsically limited in the sense that they probe the bulk material and cannot be as sensitive to thin layers of near-surface dissolution/growth. The present study therefore uses surface sensitive shallow angle X-ray diffraction to study the formation of amorphous calcium phosphate and hydroxyapatite on Bioglass((R)) samples, pre-reacted in simulated body fluid (SBF). Unreacted Bioglass((R)) is dominated by a broad amorphous feature around 2.2 A(-1) which is characteristic of sodium calcium silicate glass. After reacting Bioglass((R)) in SBF a second broad amorphous feature evolves ~1.6 A(-1) which is attributed to amorphous calcium phosphate. This feature is evident for samples after only 4 h reacting in SBF and by 8 h the amorphous feature becomes comparable in magnitude to the background signal of the bulk Bioglass((R)). Bragg peaks characteristic of hydroxyapatite form after 1-3 days of reacting in SBF.


Assuntos
Fosfatos de Cálcio/química , Cerâmica , Durapatita/química , Difração de Raios X/métodos , Propriedades de Superfície
15.
J Eur Acad Dermatol Venereol ; 21(8): 1074-81, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17714128

RESUMO

BACKGROUND: Regular thorough skin self-examination (TSSE) has potential for detecting melanoma early and reducing melanoma mortality. OBJECTIVES: We sought to model factors associated with skin self-examination (SSE) and test whether efficacy and attitudes about SSE mediated these relationships. PATIENTS/METHODS: The Check-It-Out project is a randomized trial of an intervention to encourage TSSE; 2126 participants were recruited from the practices of primary care physicians. Correlates predicting baseline TSSE included demographic variables, skin cancer risk, physician advice to examine skin, and appropriate conditions for conducting SSE (availability of partner to assist with self-examination, availability of a wall mirror, and use of contact lenses/glasses). RESULTS: Those who were given physician advice, had a wall mirror, and had a partner available were more likely to perform TSSE. LIMITATIONS: We identified the factors associated with concurrent TSSE practices. Further research is needed to determine if these same factors predict future behaviour. Our findings may not be applicable in geographical areas other than our recruitment area. CONCLUSIONS: Primary care providers can recommend SSE and provide materials to increase ability to recognize skin problems. Providing instructions and aids for conducting TSSE may increase self-efficacy.


Assuntos
Melanoma/diagnóstico , Autoexame , Neoplasias Cutâneas/diagnóstico , Feminino , Promoção da Saúde , Humanos , Masculino , Pessoa de Meia-Idade
16.
J Econ Entomol ; 100(2): 283-90, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17461048

RESUMO

Green lacewings are widely used biological control agents for various insect pests. To meet the needs of growers, green lacewings are being mass-reared commercially around the world. A common salt shaker has been used regularly to distribute eggs into Verticel lacewing larval rearing units. This technique is time consuming and inefficient because the number of eggs distributed in each cell is inconsistent. The multiple orifice distribution (MOD) system described here greatly improved egg distribution efficiency by increasing the percentage of Verticel cells containing the desired one to four eggs per cell (i.e., 40.8 and 52.1% by using salt shaker method versus 61.9% by using the MOD system). This mechanical system significantly reduced the labor and time involved in the process and would cost under $3500. In addition, this new system could be modified for distribution of other insect eggs.


Assuntos
Entomologia/métodos , Insetos/crescimento & desenvolvimento , Animais , Entomologia/economia , Entomologia/instrumentação , Insetos/fisiologia , Larva/crescimento & desenvolvimento , Larva/fisiologia , Controle Biológico de Vetores/economia
17.
Vet Comp Orthop Traumatol ; 19(4): 219-27, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17143394

RESUMO

The tibial tuberosity advancement (TTA) procedure was developed to treat dogs with cranial cruciate ligament deficient stifles. A retrospective, descriptive study was performed on 57 dogs that underwent unilateral or bilateral TTA. Medical records were reviewed and pre-, postoperative and follow-up radiographs were evaluated for patellar ligament-tibial plateau angle (alpha), distance of the tibial tuberosity advancement and progression of degenerative joint disease. A questionnaire was sent to all owners to obtain their assessment of the procedural outcome. Sixty-five stifles in 57 dogs received a TTA. Mean age was 5.2 +/- 2.5 years while mean weight was 39.7 +/- 11.9 kg. Eighteen breeds were represented with Labrador retrievers and mixed breeds predominating. The mean duration of lameness prior to surgery was 6.2 +/- 6.7 months, with a median lameness score of 3/4. Fifty-nine percent of cases encountered complications, the majority of which were minor. Major post-operative complications were uncommon but consisted of implant failure, tibial crest displacement and medial meniscal tears. The mean radiographic preoperative angle alpha was 100 degrees, while the postoperative was 95.5 degrees. Mean osteoarthrosis scores were significantly different between preoperative and follow-up radiographs with 67% of cases showing radiographic progression. Seventy percent of owners responded to the survey with overall outcome considered good to excellent in 90%. Activity level was improved in 90% of responses. TTA subjectively appears to be a useful alternative in the management of cranial cruciate ligament disease. Few severe complications were encountered. Good clinical outcome and owner satisfaction was reported with the procedure in this set of cases.


Assuntos
Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/cirurgia , Cães/lesões , Instabilidade Articular/veterinária , Meniscos Tibiais/cirurgia , Joelho de Quadrúpedes/lesões , Joelho de Quadrúpedes/cirurgia , Animais , Ligamento Cruzado Anterior/diagnóstico por imagem , Cães/cirurgia , Feminino , Escala de Gravidade do Ferimento , Instabilidade Articular/diagnóstico por imagem , Instabilidade Articular/epidemiologia , Instabilidade Articular/cirurgia , Coxeadura Animal , Masculino , Maryland/epidemiologia , Linhagem , Complicações Pós-Operatórias/veterinária , Radiografia , Amplitude de Movimento Articular , Estudos Retrospectivos , Joelho de Quadrúpedes/diagnóstico por imagem , Inquéritos e Questionários , Virginia/epidemiologia
19.
J Nematol ; 37(4): 473-6, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19262893

RESUMO

Grain yields of spring wheat (Triticum aestivum L. cvs. AC Barrie, AC Walton, AC Wilmot, Belvedere, Glenlea) in field plots over a 3-year period were increased (P < 0.001) by an average of 0.56 (25.1%) and 1.17 (52.5%) tonnes/ha in comparison to untreated check plots when aldicarb at 2.24 kg or fosthiazate at 13.5 a.i./ha, respectively, were broadcast and incorporated into the soil to suppress nematodes. The planned F test using orthogonal coefficients indicated that the mean response of grain yields to nematicide treatments of AC Barrie and Glenlea, which are grown primarily in the prairie provinces of Canada, was greater (48.5%) than the mean response of Belvedere, AC Walton, and AC Wilmot (33.7%), which are more common in the Maritime region of Canada (P < 0.001). Root lesion nematodes (primarily Pratylenchus penetrans) in wheat roots and in root zone soil at harvest were reduced by the nematicide applications (P < 0.001). Bacterial-feeding nematodes (primarily Diplogaster lheritieri (Maupas)) in root zone soil were also suppressed by fosthiazate (P < 0.01) but not by aldicarb. These data indicate that root lesion nematodes cause substantial yield losses in spring wheat in the Maritime region of Canada.

20.
J Vet Pharmacol Ther ; 27(3): 169-81, 2004 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15189303

RESUMO

The interrelationships between physicochemical properties, absorption and potency of 2-desoxoparaherquamide and five analogs, representing a new anthelmintic class, were evaluated in in vitro and in vivo assays. At pH 7.5, rates of drug absorption by the gastrointestinal nematode Haemonchus contortus and jird small intestine, parameterized by the permeability coefficient, P(e), ranged from 1.2-2.4 x 10(-4) cm/min (nematode) to 2.5-5.5 x 10(-3) cm/min (jird). In the jird intestine, absorption was pH-dependent, with P(e) at pH 7.5 being twice that at pH 4.5, reflecting the negative influence of protonation on transport of these weakly basic molecules. Each compound rapidly paralyzed H. contortus during in vitro exposure to therapeutically relevant concentrations (1-10 microm). The kinetics of drug action on motility in vivo mirrored their in vitro effects; motility concentrations were reduced in nematodes collected from jird stomach 3 h following oral drug dosing, by which time > or =50% clearance of the parasites had occurred. The nematode/medium partition coefficient K ranged from 10.1 to 16.1, consistent with the lipophilic nature of the compounds. The time required to reduce motility in vitro by 50% (t50*) and P(e) were used to determine C(n)*, the concentration of drug in the nematode at t50*, as an indicator of intrinsic potency. In the jird, the apparent potencies of the compounds were insensitive to route of administration (i.e. oral = i.v. = i.p. = i.m.) for H. contortus and two other gastrointestinal nematodes, Ostertagia ostertagi and Trichostrongylus colubriformis; topical administration, however, required three to 10-fold higher doses for equivalent efficacy.


Assuntos
Anti-Helmínticos/farmacologia , Hemoncose/veterinária , Haemonchus/efeitos dos fármacos , Indolizinas/farmacologia , Doenças dos Ovinos/tratamento farmacológico , Compostos de Espiro/farmacologia , Absorção , Administração Oral , Animais , Anti-Helmínticos/administração & dosagem , Anti-Helmínticos/farmacocinética , Feminino , Hemoncose/tratamento farmacológico , Haemonchus/metabolismo , Indolizinas/administração & dosagem , Indolizinas/farmacocinética , Injeções Intramusculares/veterinária , Injeções Intraperitoneais/veterinária , Injeções Intravenosas/veterinária , Testes de Sensibilidade Parasitária , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/parasitologia , Compostos de Espiro/administração & dosagem , Compostos de Espiro/farmacocinética , Trichostrongyloidea/efeitos dos fármacos , Trichostrongyloidea/metabolismo
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