Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
1.
J Environ Biol ; 34(4): 689-94, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24640244

RESUMO

Seasonal dynamics studies on wheat aphid complex, comprising of four major species and its predator Coccinella septempunctata were conducted in context to abiotic and biotic factors. The alate form of aphids appeared on the crop during the 1st week of December. The colony build up of aphid complex started during the 2nd week of January and peak was observed after the 1st week of March. Wheat aphid complex started declining in the last week of March and disappeared by mid April. The abiotic factors like maximum temperature and evaporation were most important for the build up of aphids. The grubs and adults of C. septempunctata appeared on the crop during mid February and their population increased with the increase in aphid population. The grubs and adult population showed a strong positive correlation with aphid complex. The population of predators had significant positive correlation with maximum, minimum, mean temperature, sunshine and vapour pressure. The population of aphids declined after the 2nd week of March due to the rise in temperature, crop maturity and this in turn resulted in the lowering of the predator population. The studies evaluate in detail the abiotic and biotic factors regulating the wheat aphid complex and C. septempunctata populations under wheat agro-ecosystem.


Assuntos
Besouros/patogenicidade , Estações do Ano , Triticum/crescimento & desenvolvimento , Triticum/parasitologia , Animais , Afídeos , Controle Biológico de Vetores , Comportamento Predatório/fisiologia , Luz Solar , Temperatura
2.
J Bone Joint Surg Am ; 82(8): 1096-101, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10954098

RESUMO

BACKGROUND: Notching of the anterior femoral cortex during total knee arthroplasty has been implicated as a cause of subsequent periprosthetic supracondylar femoral fracture. However, other than observational clinical data, no reliable association between these events has been established, to our knowledge. The purpose of the present study was to investigate the biomechanical effects of notching of the anterior femoral cortex. METHODS: The femoral component of a total knee replacement was implanted in twelve matched pairs of human cadaveric femora; one specimen in each pair had preservation of the anterior femoral cortex, and the other had a full-thickness cortical defect created just proximal to the anterior flange of the femoral component. The pairs were then subjected to either bending or torsional loading to failure. Both the fracture pattern and the quantitative load to failure were analyzed. Two matched pairs were excluded from the analysis because of inadvertent fracture during placement of the component. RESULTS: Following the application of a bending load, femora with notching of the anterior femoral cortex sustained a short oblique fracture that originated at the cortical defect proximal to the femoral component and femora without notching had a midshaft fracture. In contrast, notching of the anterior femoral cortex had no effect on the fracture pattern that was observed after the application of a torsional load. The mean load to failure was significantly reduced by notching in both testing modes. Notching decreased bending strength from 11,813 to 9690 newtons (18 percent; p = 0.0034), and it decreased torsional strength from 134.7 to 81.8 newton-meters (39.2 percent; p = 0.01). CONCLUSIONS: Biomechanical testing demonstrated that notching of the anterior femoral cortex significantly lessens the load to failure following total knee arthroplasty and influences the subsequent fracture pattern. These effects are manifested in different ways under the two loading conditions: the fracture pattern is altered under bending load, and there is a greater quantitative decrease in load to failure with torsional loading. CLINICAL RELEVANCE: Weakening of the femur by notching of the anterior cortex after total knee arthroplasty may warrant alteration in the customary postoperative regimen for these patients. Manipulation of a total knee replacement with a notched anterior femoral cortex should probably be avoided.


Assuntos
Artroplastia do Joelho/efeitos adversos , Fraturas do Fêmur/etiologia , Idoso , Idoso de 80 Anos ou mais , Artroplastia do Joelho/métodos , Fenômenos Biomecânicos , Cadáver , Humanos
3.
Am J Sports Med ; 27(4): 417-21, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10424209

RESUMO

We investigated the effects of aging and various treatments on rat patellar tendon using an in vitro model. In the first part of the study, the 3H-thymidine and 3H-proline incorporation rates at 12 and 24 hours were determined in transected patellar tendon explants from young (21 days), intermediate age (8 to 10 weeks), and older (4 to 6 months) rats. In the second part, the same incorporation rates were measured in the older tendon explants in response to treatment with control medium, medium with a high and low concentration of indomethacin, and medium with a high and low concentration of dexamethasone. Finally, the effects of ultrasound treatment were measured and compared with a sham ultrasound treatment. The results indicated an age-dependent response of the tendon. The youngest specimens consistently showed the highest incorporation rates. The addition of a high concentration of dexamethasone resulted in a small negative effect on the 3H-thymidine incorporation. Ultrasound and indomethacin had no significant effects. This study indicates that aging is associated with a lower metabolic activity of tendon. In this model, currently used treatment methods failed to result in direct positive effects on tendon tissue, and a high concentration of dexamethasone appeared to have a small negative effect.


Assuntos
Envelhecimento/fisiologia , Tendões/metabolismo , Animais , Anti-Inflamatórios não Esteroides/farmacologia , Dexametasona/farmacologia , Glucocorticoides/farmacologia , Técnicas In Vitro , Indometacina/farmacologia , Masculino , Ratos , Ratos Sprague-Dawley , Tendinopatia/tratamento farmacológico , Tendinopatia/fisiopatologia , Tendinopatia/terapia , Tendões/efeitos dos fármacos , Terapia por Ultrassom
5.
Clin Orthop Relat Res ; (355): 35-46, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9917589

RESUMO

An animal model for the study of heterotopic ossification was developed and the effects of perioperative radiation were analyzed. In Phase I, New Zealand White rabbits (n = 18) underwent surgery either with or without muscle injury on each hip to establish the most reliable model in which to study heterotopic ossification. In Phase II, rabbits (n = 36) underwent either 400, 800, or 1200 cGy radiation to one hip 24 hours after bilateral hip surgery to establish a dose response relationship for postoperative radiation therapy. In Phase III, rabbits (n = 24) underwent preoperative radiation therapy (800 cGy) at 4, 16, or 24 hours preoperatively to investigate the mechanism of action and efficacy of preoperative radiation therapy. Monthly radiographs were graded by blinded observers for severity of heterotopic ossification. Mean grade, intraobserver and interobserver variability, and statistical significance were evaluated. In Phase II, 17 of 18 rabbits generated heterotopic ossification in both hips, and the mean grade of heterotopic ossification was always greater on the operative side with intentional muscle injury. Variability in the grading was considered excellent. Phase II revealed that 800 cGy was the minimal effective dose. Contrary to hypothesis, Phase III revealed an increasing grade of heterotopic ossification coinciding with a decreasing preoperative time interval, with the difference in heterotopic ossification grade with 24-hour versus 4-hour preoperative radiation being significant. The rabbit model is reliable and reproducible and closely resembles the human clinical situation after hip surgery. Preoperative and postoperative radiation effectively prevented heterotopic ossification formation. The results support the use of preoperative radiation and establish a need for additional investigation regarding the mechanism of action and timing of preoperative radiation therapy.


Assuntos
Artroplastia de Quadril/efeitos adversos , Modelos Animais de Doenças , Ossificação Heterotópica/prevenção & controle , Ossificação Heterotópica/radioterapia , Animais , Artroplastia de Quadril/métodos , Relação Dose-Resposta à Radiação , Humanos , Masculino , Variações Dependentes do Observador , Ossificação Heterotópica/diagnóstico por imagem , Ossificação Heterotópica/etiologia , Assistência Perioperatória , Coelhos , Radiografia , Dosagem Radioterapêutica , Distribuição Aleatória , Reprodutibilidade dos Testes , Índice de Gravidade de Doença , Método Simples-Cego , Fatores de Tempo
6.
Clin Orthop Relat Res ; (367): 107-16, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10546604

RESUMO

This prospective randomized study was undertaken to evaluate the vastus splitting approach as an alternative to the median parapatellar approach in primary total knee arthroplasty. Fifty-one knees in 42 patients were randomized preoperatively. Clinical parameters were evaluated preoperatively and at regular postoperative intervals. Electromyography was performed preoperatively and postoperatively to evaluate each approach relative to its effect on the innervation of the quadriceps mechanism. There were no significant preoperative differences. Postoperatively, there were no significant differences regarding strength, range of motion, knee scores, tourniquet time, proprioception, or patellar replacement. There were significantly more lateral releases performed and greater blood loss in the patients in the parapatellar group. The results of all preoperative electromyograms were normal, as were all of the results of postoperative electromyograms in the patients in the parapatellar group. However, the results of nine of 21 (43%) of the electromyograms performed postoperatively on patients who had the vastus splitting approach were abnormal. Significantly fewer lateral releases were performed and there was less blood loss in the patients in the vastus group. However, the postoperative electromyographic results revealed neurologic injuries in the vastus medialis muscle that only were present after the vastus splitting approach. The clinical significance of denervation of the vastus medialis muscle by the vastus approach remains to be determined by longer term clinical and electromyographic studies.


Assuntos
Artroplastia do Joelho/métodos , Músculo Esquelético/cirurgia , Adulto , Idoso , Eletromiografia , Feminino , Humanos , Articulação do Joelho/fisiopatologia , Perna (Membro) , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/fisiopatologia , Medição da Dor , Complicações Pós-Operatórias , Estudos Prospectivos , Amplitude de Movimento Articular
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa