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1.
CBE Life Sci Educ ; 21(4): ar70, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36149669

RESUMO

Course-based undergraduate research experiences (CUREs) integrate an authentic research experience for students into a laboratory course. CUREs provide many of the same benefits to students as individual faculty-mentored research experiences. However, faculty experiences in teaching CUREs are not as well understood. There are no studies that compare faculty's anticipated experiences to actual experiences, and little comparison of the faculty experience by institution. Through interviews with eight biology faculty from four institutions, the faculty experience in implementing a CURE in an introductory biology laboratory was explored using qualitative analysis. Institutions included: a small, minority-serving, women's, primarily undergraduate university; a small, residential, primarily undergraduate college; a midsized doctoral university; and a large community college. Interviews were conducted at three time points: before professional development (PD), after the initial semester of teaching the CURE, and after teaching the CURE at least twice (1 year later). Faculty described resources, benefits, challenges, and feelings about teaching the CURE. However, anticipated experiences were often not the same as those actually experienced. There were also institutional differences in resources, benefits, challenges, and feelings. Implications for CURE PD include specific content such as strategies for teaching effective research group work, development of student proposals, and student time management.


Assuntos
Docentes , Estudantes , Biologia/educação , Feminino , Humanos , Laboratórios , Universidades
3.
Bone Joint J ; 99-B(3): 369-375, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28249978

RESUMO

AIMS: The aims of this study were: firstly, to investigate the influence of the thickness of cartilage at the sigmoid notch on the inclination of the distal radioulnar joint (DRUJ), and secondly, to compare the sensitivity and specificity of MRI with plain radiographs for the assessment of the inclination of the articular surface of the DRUJ in the coronal plane. PATIENTS AND METHODS: Contemporaneous MRI images and radiographs of 100 wrists from 98 asymptomatic patients (mean age 43 years, (16 to 67); 52 male, 53%) with no history of a fracture involving the wrist or surgery to the wrist, were reviewed. The thickness of the cartilage at the sigmoid notch, inclination of the DRUJ and Tolat Type of each DRUJ were determined. RESULTS: The assessment using MRI scans and cortical bone correlated well with radiographs, with a kappa value of 0.83. The mean difference between the inclination using the cortex and cartilage on MRI scans was 12°, leading to a change of Tolat type of inclination in 66% of wrists. No reverse oblique (Type 3) inclinations were found when using the cartilage to assess inclination. CONCLUSION: These data revealed that when measuring the inclination of the DRUJ using cartilage, reverse oblique inclinations might not exist. The data suggest that performing an ulna shortening osteotomy might be reasonable even in distal radioulnar joints where the plain radiographic appearance suggests an unfavourable reverse oblique inclination in the coronal plane. We recommend using MRI to validate radiographs in those that appear to be reverse oblique (Tolat Type 3), as the true inclination might be different, thereby removing one possible contraindication to ulnar shortening. Cite this article: Bone Joint J 2017;99-B:369-75.


Assuntos
Cartilagem Articular/anatomia & histologia , Articulação do Punho/anatomia & histologia , Adolescente , Adulto , Idoso , Cartilagem Articular/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Radiografia , Rádio (Anatomia)/anatomia & histologia , Rádio (Anatomia)/diagnóstico por imagem , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Ulna/anatomia & histologia , Ulna/diagnóstico por imagem , Articulação do Punho/diagnóstico por imagem , Adulto Jovem
4.
R Soc Open Sci ; 4(12): 170681, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29308221

RESUMO

Cognitive bias modification is a potential low-intensity intervention for mood disorders, but previous studies have shown mixed success. This study explored whether facial interpretation bias modification (FIBM), a similar paradigm designed to shift emotional interpretation (and/or perception) of faces would transfer to: (i) self-reported symptoms and (ii) a battery of cognitive tasks. In a preregistered, double-blind randomized controlled trial, healthy participants received eight online sessions of FIBM (N = 52) or eight sham sessions (N = 52). While we replicate that FIBM successfully shifts ambiguous facial expression interpretation in the intervention group, this failed to transfer to the majority of self-report or cognitive measures. There was, however, weak, inconclusive evidence of transfer to a self-report measure of stress, a cognitive measure of anhedonia, and evidence that results were moderated by trait anxiety (whereby transference was greatest in those with higher baseline symptoms). We discuss the need for work in both larger and clinical samples, while urging caution that these FIBM training effects may not transfer to clinically relevant domains.

5.
J Hand Surg Eur Vol ; 42(2): 127-136, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27655647

RESUMO

This Delphi study aimed to reach consensus on important facilitators and barriers for return-to-work following surgery for non-traumatic upper extremity conditions. In Round 1, experts ( n = 42) listed 134 factors, which were appraised in Rounds 2 and 3. Consensus (⩾85% agreement) was achieved for 13 facilitators (high motivation to return-to-work; high self-efficacy for return-to-work and recovery; availability of modified/alternative duties; flexible return-to-work arrangements; positive coping skills; limited heavy work exertion; supportive return-to-work policies; supportive supervisor/management; no catastrophic thinking; no fear avoidance to return-to-work; no fear avoidance to pain/activity; return to meaningful work duties; high job satisfaction) and six barriers (mood disorder diagnosis; pain/symptoms at more than one musculoskeletal site; heavy upper extremity exertions at work; lack of flexible return-to-work arrangements; lack of support from supervisor/management; high level of pain catastrophizing). Future prognostic studies are required to validate these biopsychosocial factors to further improve return-to-work outcomes. LEVEL OF EVIDENCE: V.


Assuntos
Consenso , Doenças Musculoesqueléticas/fisiopatologia , Doenças Musculoesqueléticas/psicologia , Retorno ao Trabalho , Extremidade Superior , Adaptação Psicológica , Adulto , Técnica Delphi , Medo , Feminino , Humanos , Satisfação no Emprego , Masculino , Pessoa de Meia-Idade , Motivação , Doenças Musculoesqueléticas/cirurgia , Avaliação de Resultados em Cuidados de Saúde , Adulto Jovem
6.
J Viral Hepat ; 23(12): 1009-1016, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27509844

RESUMO

Prisoners are a priority group for hepatitis C (HCV) treatment. Although treatment durations will become shorter using directly acting antivirals (DAAs), nearly half of prison sentences in Scotland are too short to allow completion of DAA therapy prior to release. The purpose of this study was to compare treatment outcomes between prison- and community-based patients and to examine the impact of prison release or transfer during therapy. A national database was used to compare treatment outcomes between prison treatment initiates and a matched community sample. Additional data were collected to investigate the impact of release or transfer on treatment outcomes. Treatment-naïve patients infected with genotype 1/2/3/4 and treated between 2009 and 2012 were eligible for inclusion. 291 prison initiates were matched with 1137 community initiates: SVRs were 61% (95% CI 55%-66%) and 63% (95% CI 60%-66%), respectively. Odds of achieving a SVR were not significantly associated with prisoner status (P=.33). SVRs were 74% (95% CI 65%-81%), 59% (95% CI 42%-75%) and 45% (95% CI 29%-62%) among those not released or transferred, transferred during treatment, or released during treatment, respectively. Odds of achieving a SVR were significantly associated with release (P<.01), but not transfer (P=.18). Prison-based HCV treatment achieves similar outcomes to community-based treatment, with those not released or transferred during treatment doing particularly well. Transfer or release during therapy should be avoided whenever possible, using anticipatory planning and medical holds where appropriate.


Assuntos
Antivirais/uso terapêutico , Hepatite C Crônica/tratamento farmacológico , Resposta Viral Sustentada , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prisões , Características de Residência , Escócia , Resultado do Tratamento , Adulto Jovem
7.
Vaccine ; 28(4): 940-9, 2010 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-19925904

RESUMO

The F(0)F(1) ATPase plays a central role in both the generation of ATP and the utilisation of ATP for cellular processes such as rotation of bacterial flagella. We have deleted the entire operon encoding the F(0)F(1) ATPase, as well as genes encoding individual F(0) or F(1) subunits, in Salmonella enteric serovar Typhimurium. These mutants were attenuated for virulence, as assessed by bacterial counts in the livers and spleens of intravenously infected mice. The attenuated in vivo growth of the entire atp operon mutant was complemented by the insertion of the atp operon into the malXY pseudogene region. Following clearance of the attenuated mutants from the organs, mice were protected against challenge with the virulent wild type parent strain. We have shown that the F(0)F(1) ATPase is important for bacterial growth in vivo and that atp mutants are effective live attenuated vaccines against Salmonella infection.


Assuntos
ATPases Bacterianas Próton-Translocadoras/genética , Deleção de Genes , Vacinas contra Salmonella/genética , Vacinas contra Salmonella/imunologia , Salmonella typhimurium/enzimologia , Salmonella typhimurium/patogenicidade , Animais , Contagem de Colônia Microbiana , Feminino , Genes Bacterianos , Teste de Complementação Genética , Fígado/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Óperon , Salmonelose Animal/microbiologia , Salmonella typhimurium/genética , Salmonella typhimurium/imunologia , Baço/microbiologia , Vacinas Atenuadas/genética , Vacinas Atenuadas/imunologia , Virulência
8.
Infect Immun ; 78(1): 326-36, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19884329

RESUMO

In Salmonella enterica serovar Typhimurium, trxA encodes thioredoxin 1, a small, soluble protein with disulfide reductase activity, which catalyzes thiol disulfide redox reactions in a variety of substrate proteins. Thioredoxins are involved as antioxidants in defense against oxidative stresses, such as exposure to hydrogen peroxide and hydroxyl radicals. We have made a defined, complete deletion of trxA in the mouse-virulent S. Typhimurium strain SL1344 (SL1344 trxA), replacing the gene with a kanamycin resistance gene cassette. SL1344 trxA was attenuated for virulence in BALB/c mice by the oral and intravenous routes and when used in immunization experiments provided protection against challenge with the virulent parent strain. SL1344 trxA induced less inflammation in murine spleens and livers than SL3261, the aroA mutant, live attenuated vaccine strain. The reduced splenomegaly observed following infection with SL1344 trxA was partially attributed to a reduction in the number of both CD4(+) and CD8(+) T cells and B lymphocytes in the spleen and reduced infiltration by CD11b(+) cells into the spleen compared with spleens from mice infected with SL3261. This less severe pathological response indicates that a trxA mutation might be used to reduce reactogenicity of live attenuated vaccine strains. We tested this by deleting trxA in SL3261. SL3261 trxA was also less inflammatory than SL3261 but was slightly less effective as a vaccine strain than either the SL3261 parent strain or SL1344 trxA.


Assuntos
Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Inflamação/induzido quimicamente , Salmonelose Animal/prevenção & controle , Vacinas contra Salmonella/imunologia , Salmonella typhimurium/metabolismo , Animais , Proteínas de Bactérias/genética , Injeções Intravenosas , Lipopolissacarídeos , Fígado/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Mutação , Salmonelose Animal/patologia , Vacinas contra Salmonella/administração & dosagem , Vacinas contra Salmonella/efeitos adversos , Salmonella typhimurium/genética , Salmonella typhimurium/imunologia , Baço/patologia , Fatores de Tempo , Receptor 4 Toll-Like/genética , Virulência
9.
Microbiology (Reading) ; 155(Pt 10): 3403-3410, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19589833

RESUMO

The enzyme phosphoglucomutase (Pgm) catalyses the interconversion of glucose 1-phosphate and glucose 6-phosphate and contributes to glycolysis and the generation of sugar nucleotides for biosynthesis. To assess the role of this enzyme in the biology of the pathogen Salmonella enterica serovar Typhimurium we have characterized a pgm deletion mutant in strain SL1344. Compared to SL1344, SL1344 pgm had impaired growth in vitro, was deficient in the ability to utilize galactose as a carbon source and displayed reduced O-antigen polymer length. The mutant was also more susceptible to antimicrobial peptides and showed decreased fitness in the mouse typhoid model. The in vivo phenotype of SL1344 pgm indicated a role for pgm in the early stages of infection, most likely through deficient O-antigen production. Although pgm mutants in other pathogens have potential as live attenuated vaccine strains, SL1344 pgm was not sufficiently attenuated for such use.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Farmacorresistência Bacteriana , Antígenos O/biossíntese , Fosfoglucomutase/metabolismo , Salmonella typhimurium/enzimologia , Animais , Carbono/metabolismo , Feminino , Galactose/metabolismo , Deleção de Genes , Fígado/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Viabilidade Microbiana , Fosfoglucomutase/genética , Salmonelose Animal/microbiologia , Salmonella typhimurium/genética , Salmonella typhimurium/crescimento & desenvolvimento , Baço/microbiologia , Virulência
10.
Microb Pathog ; 46(5): 261-5, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19486643

RESUMO

To assess the role of the glycolytic enzyme phosphofructokinase (Pfk) in the in vivo fitness of the pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) we have generated single and double gene deletion mutants of the two known isoforms of this enzyme, pfkA and pfkB. In a mouse model of typhoid fever, bacterial counts in the spleen and liver were similar between wild type and single pfkA and pfkB mutant-infected mice. However, a double pfkAB mutant was significantly attenuated for growth in vivo. This defect was complemented by provision of either pfkA or pfkB on pBR322. Together these data show that Pfk activity is required for the full in vivo fitness of S. Typhimurium with functional redundancy between pfkA and pfkB. The level of attenuation of the pfkAB double mutant was not sufficient for its consideration as a live attenuated vaccine strain.


Assuntos
Proteínas de Bactérias/metabolismo , Fosfofrutoquinase-1/metabolismo , Fosfofrutoquinase-2/metabolismo , Salmonella typhimurium/enzimologia , Salmonella typhimurium/crescimento & desenvolvimento , Febre Tifoide/microbiologia , Animais , Proteínas de Bactérias/genética , Feminino , Humanos , Fígado/microbiologia , Camundongos , Camundongos Endogâmicos BALB C , Fosfofrutoquinase-1/genética , Fosfofrutoquinase-2/genética , Salmonella typhimurium/genética , Deleção de Sequência , Baço/microbiologia
11.
Microbiology (Reading) ; 155(Pt 1): 220-228, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19118362

RESUMO

The Gram-negative Tol-Pal system of envelope proteins plays a key role in maintaining outer membrane integrity and contributes to the virulence of several pathogens. We have investigated the role of one of these proteins, TolA, in the biology of Salmonella enterica serovar Typhimurium. Deletion of tolA rendered strain SL1344 more susceptible to killing by bile and human serum. In addition the mutant had impaired membrane integrity and displayed alterations in LPS production. The tolA mutant was highly attenuated in mouse infections via the oral and intravenous routes. Importantly, each phenotype displayed by the mutant was complemented by provision of tolA in trans. The tolA gene therefore contributes to virulence, membrane integrity, LPS production and bile and serum resistance in S. enterica serovar Typhimurium SL1344. Finally, immunization with the tolA mutant provided significant protection against subsequent challenge with wild-type SL1344. The Tol-Pal system is therefore a potential target in the development of novel attenuated live vaccines against Salmonella and other Gram-negative pathogens.


Assuntos
Deleção de Genes , Proteínas de Membrana/genética , Infecções por Salmonella/prevenção & controle , Vacinas contra Salmonella , Salmonella typhimurium/patogenicidade , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Membrana Celular , Feminino , Humanos , Imunização , Lipopolissacarídeos/metabolismo , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Salmonella/imunologia , Infecções por Salmonella/microbiologia , Salmonella typhimurium/genética , Salmonella typhimurium/fisiologia , Virulência
14.
J Exp Biol ; 203(Pt 23): 3639-54, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11060225

RESUMO

In many species of frog, the forelimb muscles important in amplexus are known to be much larger in males than in females. We studied this dimorphism in three forelimb muscles in the bullfrog [abductor indicus longus (AIL), flexor carpi radialis (FCR) and extensor carpi radialis (ECR)] by testing their isometric contractile properties. One muscle that is not dimorphic, the extensor carpi ulnaris (ECU), was also studied as a control. In addition to being greater in wet mass and in cross-sectional area in the males, our data show that the dimorphic muscles also produce significantly larger isometric forces in males than in females. The tetanic force per cm(2) of muscle cross-sectional area did not differ between the sexes, so that force within a muscle varies directly with muscle size. However, a number of the contractile variables we measured show that male muscles differ functionally from those of females. The male twitch contraction times were significantly longer in the AIL, and the male half-relaxation times were longer in both the AIL and FCR. These two dimorphic muscles were also significantly less fatiguable in males than were the corresponding female muscles. Their higher endurance resulted from the maintenance of high levels of unrelaxed force sustained between trains of stimuli during the fatigue test. This sustained force is much less pronounced in the female muscles, suggesting that high levels of sustained force may be a key functional feature that enables males to maintain amplexus economically for prolonged periods.


Assuntos
Membro Anterior , Contração Isométrica , Músculo Esquelético/fisiologia , Caracteres Sexuais , Animais , Feminino , Masculino
16.
J Morphol ; 242(2): 107-24, 1999 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10521872

RESUMO

Previous studies show that anurans feed in at least three different ways. Basal frogs have a broad tongue that shortens during protraction and emerges only a short distance from the mouth. Some frogs have long, narrow tongues that elongate dramatically due primarily to inertia from mouth opening, which is transferred to the tongue. A few species have a hydrostatic mechanism that produces tongue elongation during protraction. This functional diversity occurs among frogs that share the same two pairs of tongue muscles. Our study compares the isometric contractile properties of these tongue muscles among three frog species that represent each feeding mechanism. Nerves to the paired protractors and retractors were stimulated electrically in each species to record the force properties, contraction speeds, and fatigabilites of these muscles. Few differences were found in the isometric contractile properties of tongue muscles, and the greatest differences were found in the retractors, not the protractors. We propose that the unique arrangement of the tongue muscles in frogs results in a retractor that may also be coactivated with the protractor in order to produce normal tongue protraction. Inertial effects from body, head, and jaw movements, along with clear differences that we found in passive resistance of the tongues to elongation, may explain much of the behavioral variation in tongue use among species.


Assuntos
Anuros/fisiologia , Contração Isométrica/fisiologia , Músculo Liso/fisiologia , Língua/fisiologia , Animais , Bufonidae/fisiologia , Interpretação Estatística de Dados , Fadiga Muscular/fisiologia , Relaxamento Muscular/fisiologia , Especificidade da Espécie
17.
Biochem J ; 338 ( Pt 3): 701-8, 1999 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-10051442

RESUMO

MET1 and MET8 mutants of Saccharomyces cerevisiae can be complemented by Salmonella typhimurium cysG, indicating that the genes are involved in the transformation of uroporphyrinogen III into sirohaem. In the present study, we have demonstrated complementation of defined cysG mutants of Sal. typhimurium and Escherichia coli, with either MET1 or MET8 cloned in tandem with Pseudomonas denitrificans cobA. The conclusion drawn from these experiments is that MET1 encodes the S-adenosyl-l-methionine uroporphyrinogen III transmethylase activity, and MET8 encodes the dehydrogenase and chelatase activities (all three functions are encoded by Sal. typhimurium and E. coli cysG). MET8 was further cloned into pET14b to allow expression of the protein with an N-terminal His-tag. After purification, the functions of the His-tagged Met8p were studied in vitro by assay with precorrin-2 in the presence of NAD+ and Co2+. The results demonstrated that Met8p acts as a dehydrogenase and chelatase in the biosynthesis of sirohaem. Moreover, despite the fact that S. cerevisiae does not make cobalamins de novo, we have shown also that MET8 is able to complement cobalamin cobaltochelatase mutants and have revealed a subtle difference in the early stages of the anaerobic cobalamin biosynthetic pathways between Sal. typhimurium and Bacillus megaterium.


Assuntos
Proteínas de Bactérias , Ferroquelatase , Proteínas Fúngicas/metabolismo , Heme/análogos & derivados , Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae/metabolismo , Vitamina B 12/biossíntese , Sequência de Bases , Clonagem Molecular , Primers do DNA , Escherichia coli/genética , Proteínas Fúngicas/genética , Teste de Complementação Genética , Heme/biossíntese , Liases/metabolismo , Metiltransferases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Salmonella typhimurium/genética
18.
Med Microbiol Immunol ; 188(1): 1-7, 1999 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10691087

RESUMO

The aim of this study was to determine the kinetics, the dissemination of the infection and the immunological response to Pneumocystis carinii primary infection in a non-immunosuppressed rabbit model. For this purpose, we developed a nested PCR that amplified a portion of the mitochondrial large-subunit rRNA gene of rabbit-derived P. carinii. The PCR detected P. carinii DNA in lung and bronchoalveolar lavage fluids from 14- to 45-day-old rabbits but not in their serum. No P. carinii DNA was detected in extrapulmonary organs from 28-day-old rabbits with P. carinii pneumonia. ELISA and immunoblotting analysis showed that 5-day-old pups had elevated specific IgG. The IgG concentration sharply decreased, reaching a trough on day 21, and from then onwards progressively increased as the infection cleared. Conversely, the specific IgM concentration increased during the infection and peaked on day 28. IgG mainly recognized a 50-kDa subunit of P. carinii organisms; IgM recognized first a 45-kDa subunit on day 21, whereas from day 28 onwards it also recognized the 50-kDa subunit. A P. carinii-specific splenocyte proliferative response was observed on day 45. These findings suggest that P. carinii primary infection is a time-limited and a lung-limited event and contribute new information on the relationship between the kinetics of primary P. carinii infection and the immunological response in a model that mimics the primary infections in humans.


Assuntos
Anticorpos Antifúngicos/sangue , Infecções por Pneumocystis/imunologia , Pneumocystis/imunologia , Envelhecimento/imunologia , Animais , Líquido da Lavagem Broncoalveolar/microbiologia , DNA Fúngico/análise , Modelos Animais de Doenças , Humanos , Imunocompetência , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Pulmão/microbiologia , Ativação Linfocitária , Pneumocystis/genética , Pneumocystis/isolamento & purificação , Infecções por Pneumocystis/microbiologia , Reação em Cadeia da Polimerase/métodos , Coelhos , Sensibilidade e Especificidade , Baço/imunologia , Baço/microbiologia
19.
APMIS ; 105(4): 317-21, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9164476

RESUMO

DNA was amplified from lung samples from three piglets infected with Pneumocystis carinii, using oligonucleotide primers designed to the P. carinii mitochondrial large subunit ribosomal RNA gene. The nucleotide sequence of the amplification product was determined and indicated lack of sequence variation among these pig-derived P. carinii samples at this locus. The data showed that porcine P. carinii was genetically distinct from P. carinii isolated from other mammalian host species.


Assuntos
DNA Fúngico/análise , Pulmão/virologia , Pneumocystis/classificação , Pneumonia por Pneumocystis/veterinária , Doenças dos Suínos , Animais , Sequência de Bases , Clonagem Molecular , DNA Fúngico/química , DNA Ribossômico/análise , DNA Ribossômico/genética , Humanos , Pulmão/patologia , Camundongos , Dados de Sequência Molecular , Pneumocystis/genética , Pneumocystis/isolamento & purificação , Pneumonia por Pneumocystis/fisiopatologia , Pneumonia por Pneumocystis/virologia , Reação em Cadeia da Polimerase/métodos , RNA/genética , RNA Mitocondrial , RNA Ribossômico/genética , Ratos , Homologia de Sequência do Ácido Nucleico , Suínos
20.
J Morphol ; 230(1): 1-16, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-8843687

RESUMO

This study presents a model for the step cycle patterns used during both hopping and swimming by the leopard frog, Rana pipiens. The two behaviors are essentially similar in movement pattern and in the ways they are modified from quadrupedal gaits. In hopping, there is marked hind limb extension throughout stance. The swing begins with a suspension equivalent to the leap that occurs in a galloping or bounding quadruped. Following suspension, as the frog descends from the apex of its leap, the hind limbs remain posterior and in line with the spine while they flex. Near the end of flexion, there is a rapid downward rotation of the hindquarters to bring the hind feet underneath the body. This movement utilizes the planted forelimb as a pivot. A similar pattern of movement occurs in swimming; the stance (propulsion) phase involves extension at all hind limb joints. The swing (recovery) phase begins with the hind feet fully extended and includes a protracted gliding phase, equivalent to the suspension in the hop. The hind limb then recovers to its initial position during a flexion phase. Since there is no landing and the hind limbs remain lateral rather than ventral to the pelvis, less flexion occurs in the spine or the limb joints. In both behaviors, the extensor muscles of hip (M. semimembranosus), knee (M. cruralis), and ankle (M. plantaris longus) achieve their longest lengths, when they likely can produce near maximal force, at the beginning of extension. All three muscles shorten during extension, but, because they are multiple-joint muscles, the amount of shortening is relatively small (approximately 15%). Hopping and swimming in frogs are comparable asymmetrical gaits with the same relative contact intervals (25% of stride). The step cycles in both gaits are modified from quadrupedal locomotion in the same ways: by 1) loss of knee and ankle extension toward the ground prior to landing (or end of flexion in swimming), 2) loss of a yield phase on landing (or end of flexion in swimming), and 3) inclusion of extended suspensions in both gaits.


Assuntos
Locomoção/fisiologia , Rana pipiens/fisiologia , Natação/fisiologia , Animais , Comportamento Animal , Membro Anterior/fisiologia , Membro Posterior/fisiologia , Articulações/fisiologia , Músculos/fisiologia
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