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1.
Microb Ecol ; 86(2): 1393-1404, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36445401

RESUMO

The amphibian skin microbiome is important in maintaining host health, but is vulnerable to perturbation from changes in biotic and abiotic conditions. Anthropogenic habitat disturbance and emerging infectious diseases are both potential disrupters of the skin microbiome, in addition to being major drivers of amphibian decline globally. We investigated how host environment (hydrology, habitat disturbance), pathogen presence, and host biology (life stage) impact the skin microbiome of wild Dhofar toads (Duttaphrynus dhufarensis) in Oman. We detected ranavirus (but not Batrachochytrium dendrobatidis) across all sampling sites, constituting the first report of this pathogen in Oman, with reduced prevalence in disturbed sites. We show that skin microbiome beta diversity is driven by host life stage, water source, and habitat disturbance, but not ranavirus infection. Finally, although trends in bacterial diversity and differential abundance were evident in disturbed versus undisturbed sites, bacterial co-occurrence patterns determined through network analyses revealed high site specificity. Our results therefore provide support for amphibian skin microbiome diversity and taxa abundance being associated with habitat disturbance, with bacterial co-occurrence (and likely broader aspects of microbial community ecology) being largely site specific.


Assuntos
Quitridiomicetos , Ranavirus , Animais , Efeitos Antropogênicos , Bufonidae , Pele/microbiologia , Bactérias/genética
2.
Science ; 211(4480): 402-5, 1981 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-7194506

RESUMO

Embryos of Caenorhabditis elegans develop into fertile adults after cell fragments, containing presumptive cytoplasm of somatic and germ line precursors, are extruded from uncleaved eggs or early blastomeres through laser-induced holes in the eggshells. This suggests that the determinate development of this worm is not dependent on the prelocalization of determinants in specific regions of the egg cytoplasm.


Assuntos
Caenorhabditis/embriologia , Citoplasma/fisiologia , Óvulo/fisiologia , Animais , Caenorhabditis/citologia , Diferenciação Celular , Feminino , Lasers
3.
Phys Med Biol ; 54(4): 1035-46, 2009 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-19168938

RESUMO

The application of a photoacoustic imaging instrument based upon a Fabry-Perot polymer film ultrasound sensor to imaging the superficial vasculature is described. This approach provides a backward mode-sensing configuration that has the potential to overcome the limitations of current piezoelectric based detection systems used in superficial photoacoustic imaging. The system has been evaluated by obtaining non-invasive images of the vasculature in human and mouse skin as well as mouse models of human colorectal tumours. These studies showed that the system can provide high-resolution 3D images of vascular structures to depths of up to 5 mm. It is considered that this type of instrument may find a role in the clinical assessment of conditions characterized by changes in the vasculature such as skin tumours and superficial soft tissue damage due to burns, wounds or ulceration. It may also find application in the characterization of small animal cancer models where it is important to follow the tumour vasculature over time in order to study its development and/or response to therapy.


Assuntos
Vasos Sanguíneos/anatomia & histologia , Técnicas de Imagem por Elasticidade/instrumentação , Técnicas de Imagem por Elasticidade/métodos , Aumento da Imagem/instrumentação , Interpretação de Imagem Assistida por Computador/instrumentação , Pele/anatomia & histologia , Pele/irrigação sanguínea , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Aumento da Imagem/métodos , Camundongos , Sensibilidade e Especificidade
4.
J Physiol ; 586(6): 1539-47, 2008 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-18202099

RESUMO

Mechanisms of regulatory cell volume increase following cell shrinkage include accumulation of organic osmolytes such as betaine, taurine, sorbitol, glycerophosphorylcholine (GPC) and myo-inositol. Myo-inositol is taken up by the sodium-myo-inositol-transporter SMIT1 (SLC5A3) expressed in a wide variety of cell types. Hypertonicity induces the transcription of the SMIT1 gene upon binding of the transcription factor tonicity enhancer binding protein (TonEBP) to tonicity responsive enhancers (TonE) in the SMIT1 promoter region. However, little is known about post-translational regulation of the carrier protein. In this study we show that SMIT1 is modulated by the serum- and glucocorticoid-inducible kinase SGK1, a protein genomically up-regulated by hypertonicity. As demonstrated by two-electrode voltage-clamp in the Xenopus oocyte expression system, SMIT1-mediated myo-inositol-induced currents are up-regulated by coexpression of wild type SGK1 and constitutively active (S422D)SGK1 but not by inactive (K127N)SGK1. The increase in SMIT1 activity is due to an elevated cell surface expression of the carrier while its kinetic properties remain unaffected. According to the decay of SMIT1 activity in the presence of brefeldin A, SGK1 stabilizes the SMIT1 protein in the plasma membrane. The SGK isoforms SGK2, SGK3 and the closely related protein kinase B (PKB) are similarly capable of activating SMIT1 activity. SMIT1-mediated currents are decreased by coexpression of the ubiquitin-ligase Nedd4-2, an effect counteracted by additional coexpression of SGK1. In conclusion, the present observations disclose SGK isoforms and protein kinase B as novel regulators of SMIT1 activity.


Assuntos
Tamanho Celular , Proteínas Imediatamente Precoces/metabolismo , Oócitos/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Simportadores/metabolismo , Equilíbrio Hidroeletrolítico/fisiologia , Animais , Células Cultivadas , Pressão Osmótica , Regulação para Cima/fisiologia , Xenopus laevis
5.
Appl Clin Inform ; 9(1): 54-61, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29365340

RESUMO

BACKGROUND: In 2015, the German Federal Ministry of Education and Research initiated a large data integration and data sharing research initiative to improve the reuse of data from patient care and translational research. The Observational Medical Outcomes Partnership (OMOP) common data model and the Observational Health Data Sciences and Informatics (OHDSI) tools could be used as a core element in this initiative for harmonizing the terminologies used as well as facilitating the federation of research analyses across institutions. OBJECTIVE: To realize an OMOP/OHDSI-based pilot implementation within a consortium of eight German university hospitals, evaluate the applicability to support data harmonization and sharing among them, and identify potential enhancement requirements. METHODS: The vocabularies and terminological mapping required for importing the fact data were prepared, and the process for importing the data from the source files was designed. For eight German university hospitals, a virtual machine preconfigured with the OMOP database and the OHDSI tools as well as the jobs to import the data and conduct the analysis was provided. Last, a federated/distributed query to test the approach was executed. RESULTS: While the mapping of ICD-10 German Modification succeeded with a rate of 98.8% of all terms for diagnoses, the procedures could not be mapped and hence an extension to the OMOP standard terminologies had to be made.Overall, the data of 3 million inpatients with approximately 26 million conditions, 21 million procedures, and 23 million observations have been imported.A federated query to identify a cohort of colorectal cancer patients was successfully executed and yielded 16,701 patient cases visualized in a Sunburst plot. CONCLUSION: OMOP/OHDSI is a viable open source solution for data integration in a German research consortium. Once the terminology problems can be solved, researchers can build on an active community for further development.


Assuntos
Comportamento Cooperativo , Implementação de Plano de Saúde , Hospitais Universitários , Avaliação de Resultados em Cuidados de Saúde , Alemanha , Humanos , Inquéritos e Questionários , Vocabulário
6.
FEBS Lett ; 581(29): 5586-90, 2007 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-18005662

RESUMO

Epithelial calcium (re)absorption is mediated by TRPV5 and TRPV6 channels. TRPV5 is modulated by the SGK1 kinase, a process requiring the PDZ-domain containing scaffold protein NHERF2. The present study explored whether TRPV6 is similarly regulated by SGKs and the scaffold proteins NHERF1/2. In Xenopus oocytes, SGKs activate TRPV6 by increasing its plasma membrane abundance. Deletion of the putative PDZ binding motif on TRPV6 did not abolish channel activation by SGKs. Furthermore, coexpression of neither NHERF1 nor NHERF2 affected TRPV6 or potentiated the SGKs stimulating effect. The present observations disclose a novel TRPV6 regulatory mechanism which presumably participates in calcium homeostasis.


Assuntos
Canais de Cálcio/metabolismo , Proteínas Imediatamente Precoces/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Canais de Cátion TRPV/metabolismo , Animais , Canais de Cálcio/genética , Epitélio/metabolismo , Humanos , Camundongos , Oócitos/enzimologia , Oócitos/metabolismo , Domínios PDZ , Técnicas de Patch-Clamp , Fosfoproteínas/metabolismo , Isoformas de Proteínas/metabolismo , Transdução de Sinais , Trocadores de Sódio-Hidrogênio/metabolismo , Canais de Cátion TRPV/genética , Xenopus
7.
Genetics ; 95(2): 317-39, 1980 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17249038

RESUMO

Eighty-eight mutants of C. elegans that display a roller phenotype (a helically twisted body) have been isolated and characterized genetically and phenotypically. The mutations are located in 14 different genes. Most genes contain a number of alleles. Their distribution among the chromosomes appears nonrandom, with seven of the genes being located on linkage group II, some very closely linked. The phenotypes of the mutants suggest that there are five different classes of genes, each class representing a set of similar phenotypic effects: Left Roller (four genes), Right Roller (one gene), Left Squat (one gene), Right Squat (two genes) and Left Dumpy Roller (six genes). The classes of mutants differ with respect to a number of characteristics that include the developmental stages affected and the types of aberrations observed in cuticle structure. A variety of gene interactions were found, arguing that these genes are involved in a common developmental process. The presence of alterations in cuticle morphology strongly suggests that these genes are active in the formation of the nematode cuticle.

8.
Mol Immunol ; 38(2-3): 221-9, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11532283

RESUMO

The demonstration of local complement protein synthesis leads to speculation as to the biological significance of this phenomenon. A narrative review is provided to illuminate several queries. It is difficult to establish a causal role for the locally produced complement because participation of systemic complement cannot be excluded. It is also difficult to discern whether local complement synthesis is a beneficial response to an inflammatory event or whether it promotes tissue damage. Finally, it remains to be seen if the roles of local and systemic complement differ in these respects. Extrahepatic expression of complement components of the activation pathways may provide a rapid response to microbial invasion. Once produced and activated, these proteins evoke a phlogistic response composed of cells and soluble mediators of inflammation. Many cells, not only synthesize complement proteins, but can also be stimulated via their complement receptors. This positive feedback may enhance local immune defense, especially in organs isolated from plasma components. In addition, local environmental factors in different organs may differentially regulate complement synthesis. These factors may include pro-inflammatory molecules and non-immune effectors, such as tissue ischemia/reoxygenation and drugs. Local complement dysregulation due to inhibition of activity of a complement regulatory component was shown to cause disease and restoration of the capacity to regulate the complement pathway restored health. Extrahepatic complement synthesis may also modulate local cellular responses, as to decrease detrimental damage of the inflammatory reaction. The demonstration that complement proteins play a significant role in the clearance of apoptotic cells suggests that local synthesis and activation of complement may contribute not only to tissue damage but also to tissue repair.


Assuntos
Proteínas do Sistema Complemento/biossíntese , Artrite/imunologia , Artrite/metabolismo , Infecções Bacterianas/imunologia , Infecções Bacterianas/metabolismo , Doença de Crohn/imunologia , Doença de Crohn/metabolismo , Glomerulonefrite por IGA/imunologia , Glomerulonefrite por IGA/metabolismo , Humanos , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/metabolismo , Traumatismo por Reperfusão/imunologia , Traumatismo por Reperfusão/metabolismo
9.
Methods Inf Med ; 54(3): 276-82, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25377309

RESUMO

OBJECTIVES: The secondary use of clinical data provides large opportunities for clinical and translational research as well as quality assurance projects. For such purposes, it is necessary to provide a flexible and scalable infrastructure that is compliant with privacy requirements. The major goals of the cloud4health project are to define such an architecture, to implement a technical prototype that fulfills these requirements and to evaluate it with three use cases. METHODS: The architecture provides components for multiple data provider sites such as hospitals to extract free text as well as structured data from local sources and de-identify such data for further anonymous or pseudonymous processing. Free text documentation is analyzed and transformed into structured information by text-mining services, which are provided within a cloud-computing environment. Thus, newly gained annotations can be integrated along with the already available structured data items and the resulting data sets can be uploaded to a central study portal for further analysis. RESULTS: Based on the architecture design, a prototype has been implemented and is under evaluation in three clinical use cases. Data from several hundred patients provided by a University Hospital and a private hospital chain have already been processed. CONCLUSIONS: Cloud4health has shown how existing components for secondary use of structured data can be complemented with text-mining in a privacy compliant manner. The cloud-computing paradigm allows a flexible and dynamically adaptable service provision that facilitates the adoption of services by data providers without own investments in respective hardware resources and software tools.


Assuntos
Computação em Nuvem , Informática Médica , Processamento de Linguagem Natural , Privacidade , Mineração de Dados , Humanos , Internet , Design de Software
10.
J Comp Neurol ; 192(4): 883-902, 1980 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-6968325

RESUMO

Neuromorphometric parameters of the vestibular system were determined from serial sections of temporal bones from four little brown bats. Well-developed eminentiae cruciatae project from the cristae ampullares of the anterior and posterior membranous ampullae. A total of 4,500 bipolar ganglion cells were enumerated within the vestibular ganglion. The widths of the cell somas varied from 2.5 to 20 micrometers, with 70% of them having widths between 5.0 and 12.5 micrometers. Two maxima were observed in a curve of ganglion cell density as a function of the length of the ganglion. The first maximum indicated a density of 4,800 cells per mm2 at a length 0.20 from the apex of the ganglion (in the pars dorsalis); the second, a density of 4,750 cells per mm2 at 0.38 mm (in the pars ventralis). The morphometric parameters studied were the radii of curvature of the semicircular ducts, the cross-sectional diameters of the semicircular canals and ducts, the dimensions of the cristae ampullares and their membranous ampullae, and dimensions pertaining to the statoconial organs. Surface areas (measured from graphic projections) were determined as 0.098 mm2 and 0.016 mm2 and hair cell count 500 and 1,300 cells for the saccular and utricular maculae, respectively. The radii of curvature of the three semicircular ducts, R, were dissimilar, with the anterior duct having the largest radius (R = 0.91 mm) and the posterior duct the smallest one (R = 0.69 mm). The average cross-sectional diameters of the anterior, lateral, and posterior ducts were measured as 0.11 mm, 0.14 mm, and 0.13 mm, respectively. Some of the morphological parameters were used to ascertain information regarding the dynamics of semicircular--canal function. In particular, the coefficients theta and II in the torsion pendulum model (Steinhausen, '31; Egmond et al., '49), and the time constants xi L congruent to II/delta and xi S congruent to theta/II of the torsion pendulum model were estimated for the little brown bat from these parameters. Where appropriate, comparisons were made to time constants obtained for other species.


Assuntos
Quirópteros/anatomia & histologia , Ecolocação/fisiologia , Orientação/fisiologia , Vestíbulo do Labirinto/inervação , Animais , Sáculo e Utrículo/inervação , Canais Semicirculares/inervação , Nervo Vestibular/anatomia & histologia
11.
Am J Clin Nutr ; 56(1 Suppl): 175S-178S, 1992 07.
Artigo em Inglês | MEDLINE | ID: mdl-1615878

RESUMO

When weight reduction was found to decrease blood pressure in the overweight hypertensive patient, it was hailed as the causative factor. A growing number of recent studies indicate that this association may be secondary to a correlation between diet-associated metabolic change and the sympathetic nervous system. A select group such as overweight hypertensive patients may have a genetic predisposition for such a correlation. In overweight hypertensive patients, low-calorie diet and especially very-low-calorie diet, correlate with improved glucose metabolism, a decrease in plasma insulin concentration, and altered norepinephrine concentrations and thus sympathetic nervous system activity. Several of these studies also show a lack of effect of salt intake on blood pressure. Thus, it seems that metabolic changes caused by the decrease in caloric intake are responsible for the decrease in blood pressure. These must be investigated to understand the effect of the different diets on blood pressure. Very low-calorie diets were found very useful in breaking the vicious circle of severe nonresponsive hypertension to medication.


Assuntos
Dieta Redutora , Ingestão de Energia , Hipertensão/dietoterapia , Obesidade/dietoterapia , Sistema Nervoso Simpático/fisiopatologia , Pressão Sanguínea , Peso Corporal , Humanos , Hipertensão/complicações , Hipertensão/genética , Insulina/sangue , Norepinefrina/metabolismo , Obesidade/complicações , Obesidade/genética
12.
Transplantation ; 64(11): 1550-8, 1997 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-9415555

RESUMO

BACKGROUND: Transplantation of human kidney tissue under the kidney capsule of immunodeficient animals (severe combined immunodeficiency [SCID]/Lewis and SCID/nude chimeric rats), and the subsequent intraperitoneal infusion of allogeneic human peripheral blood mononuclear cells (PBMC), results in a rapid and consistent human renal allograft rejection. We investigated the consequences of grafting human fetal kidney fragments instead of the adult tissue. METHODS: The development of human fetal kidney tissue and its interaction with allogeneic human PBMC in chimeric rats were analyzed by histology, immunohistochemistry, and in situ hybridization. RESULTS: We report successful establishment of human fetal kidney to SCID/Lewis and SCID/nude chimeric rats. The intrarenal human fetal renal implants displayed rapid growth and maintained numerous developing glomeruli and tubular structures up to 4 months after transplantation. In contrast to the adult human kidney, infusion of allogeneic human PBMC resulted in either minimal human T-cell infiltration or abundant nonrejecting T-cell infiltrates, characterized by a reduced number of T cells of the CD45RO+ or HLA-DR+ subsets, both leading to less tissue destruction as well as to continued growth of the human fetal renal tissue. This observation was found to be related to the reduced protein expression of tissue HLA class I and II, intercellular adhesion molecule 1, and vascular adhesion molecule 1 in the fetal grafts compared with the adult grafts. Lack of tissue expression of Fas ligand in the fetal grafts suggests that the latter does not contribute to the delayed rejection of human fetal kidneys. CONCLUSIONS: Our model should be useful for the study of human fetal renal development and the human alloresponse against fetal tissue.


Assuntos
Transferência Adotiva , Transplante de Rim , Leucócitos Mononucleares/imunologia , Quimera por Radiação , Adulto , Animais , Separação Celular , Citometria de Fluxo , Humanos , Rim/embriologia , Rim/imunologia , Rim/ultraestrutura , Transplante de Rim/imunologia , Transfusão de Leucócitos , Quimera por Radiação/imunologia , Ratos , Ratos Endogâmicos Lew , Ratos Nus
13.
Transplantation ; 46(4): 540-2, 1988 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3051560

RESUMO

Patients with steroid-resistant nephrotic syndrome and focal segmental glomerulosclerosis (FGS) who develop end-stage renal disease are at risk for recurrence of the disease following renal transplantation. Recurrence of the nephrotic syndrome in renal allografts of two children with primary FGS was successfully controlled by plasma exchange. This report suggests that plasma exchange instituted early in the course of recurrent nephrotic syndrome may be beneficial in some patients with steroid-resistant nephrotic syndrome and FGS.


Assuntos
Transplante de Rim , Síndrome Nefrótica/terapia , Troca Plasmática , Adolescente , Criança , Humanos , Masculino , Síndrome Nefrótica/etiologia , Recidiva , Transplante Homólogo/efeitos adversos
14.
Invest Radiol ; 32(9): 540-9, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9291042

RESUMO

RATIONALE AND OBJECTIVES: The authors developed an analytic software package for the objective and reproducible assessment of a single leg separation (SLS) in the outlet strut of Björk-Shiley convexoconcave (BSCC) prosthetic heart valves. METHODS: The radiographic cinefilm recordings of 18 phantom valves (12 intact and 6 SLS) and of 43 patient valves were acquired. After digitization of regions of interest in a cineframe, several processing steps were carried out to obtain a one-dimensional corrected and averaged density profile along the central axis of each strut leg. To characterize the degree of possible separation, two quantitative measures were introduced: the normalized pit depth (NPD) and the depth-sigma ratio (DSR). The group of 43 patient studies was divided into a learning set (25 patients) and a test set (18 patients). RESULTS: All phantom valves with an SLS were detected (sensitivity, 100%) at a specificity of 100%. The threshold values for the NPD and the DSR to decide whether a fracture was present or not were 3.6 and 2.5, respectively. On the basis of the visual interpretations of the 25 patient studies (learning set) by an expert panel, it was concluded that none of the patients had an SLS. To achieve a 100% specificity by quantitative analysis, the threshold values for the NPD and the DSR were set at 5.8 and 2.5, respectively, for the patient data. Based on these threshold values, the analysis of patient data from the test set resulted in one false-negative detection and three false-positive detections. CONCLUSIONS: An analytic software package for the detection of an SLS was developed. Phantom data showed excellent sensitivity (100%) and specificity (100%). Further research and software development is needed to increase the sensitivity and specificity for patient data.


Assuntos
Próteses Valvulares Cardíacas , Intensificação de Imagem Radiográfica/métodos , Adulto , Idoso , Processamento Eletrônico de Dados , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Imagens de Fantasmas , Falha de Prótese , Sensibilidade e Especificidade
15.
Eur J Pharmacol ; 74(1): 61-6, 1981 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-6274651

RESUMO

The effect of N-methylpyridinium-2-aldoxime methane sulphonate (P2S), a drug recommended for prophylactic and therapeutic purposes in organophosphate poisoning, on intestinal (Na-K) ATPase and adenyl cyclase activities, was tested in rats. Intestinal (Na-K) ATPase activity was determined 5 h after intragastric administration of either 0.15 M NaCl or P2S 200 mg/kg body weight. P2S decreased significantly jejunal and colonic (Na-K)ATPase activity, 17.1 +/- 4.8 (S.E.) and 13.5 +/- 3.0, as compared to that in saline-treated rats, 41.5 +/- 3.0 (S.E.) and 25.4 +/- 1.2 mumol Pi/mg protein per h, respectively. Pretreatment with methyl prednisolone did not prevent the decrease in enzyme activity induced by P2S. Mucosal PGE2 and cAMP contents, adenyl cyclase and phosphodiesterase activities, were similar in P2S and saline-treated rats. It is thus suggested that P2S-induced inhibition of intestinal (Na-K)ATPase activity might be among the mechanisms contributing to looseness of the stool frequently observed following P2S administration.


Assuntos
Adenilil Ciclases/análise , Antídotos/farmacologia , Intestinos/enzimologia , Compostos de Pralidoxima/farmacologia , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Inseticidas/intoxicação , Intestinos/efeitos dos fármacos , Masculino , Compostos Organofosforados , Ratos , Ratos Endogâmicos , Fatores de Tempo
16.
J Am Coll Surg ; 182(1): 46-54, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8542089

RESUMO

BACKGROUND: The strength of knots tied at laparoscopy was compared with that of hand-tied knots. STUDY DESIGN: The force needed to undo or break eight types of knots that were tied in fresh postmortem human stomachs was measured. The knotting performance of nylon, polyglactin 910, braided silk, polytetrafluoroethylene, braided polyester fiber, braided polyester suture, polyamide 66, and polydiaxone was also compared. RESULTS: Measurements of knot strength of two to six half hitches (hand tied) showed that four half hitches were necessary to tie a secure nonslipping knot with most monofilament threads (nylon, polytetrafluoroethylene, braided polyester suture, and polyamide 66), while three half hitches were adequate to secure a knot when polyglactin 910, braided polyester fiber, silk, and polydiaxone were used. Additional throws did not increase knot strength once the knot no longer slipped (p = NS). Some commonly tied knots, three half hitches and surgical knots at laparoscopy were weaker than the same hand-tied knots (p < 0.05) but an additional throw increased knot security (p < 0.01). Differences between laparoscopic and hand-tied knot strengths were greater for monofilament than multifilament threads. There was a wider distribution of strengths for laparoscopically tied than hand-tied knots. Four half hitches were the most secure configuration for laparoscopically tied knots and were significantly stronger than three half hitches and surgical knots (p < 0.01). The extracorporeally tied slipknot (Roeder loop) was significantly less secure than four half hitches (p < 0.05). CONCLUSIONS: This study demonstrates that laparoscopically formed knots may be weaker than those tied by hand and shows that improvements in knot strength at laparoscopy can be achieved by choice of optimal knot configuration for different suture materials.


Assuntos
Laparoscopia , Laparotomia , Técnicas de Sutura , Resistência à Tração , Estudos de Avaliação como Assunto , Humanos , Estômago/cirurgia , Suturas
17.
Pediatr Pulmonol ; 20(6): 369-71, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8649916

RESUMO

Recently a few cystic fibrosis (CF) patients with borderline or normal sweat tests have been reported. These patients present a diagnostic challenge. We aimed to study the sweat Cl/Na ratio in cystic fibrosis patients and to assess whether this ratio could be used as a diagnostic criteria. The mean sweat Cl/Na ratio of 3 groups was compared: Group A: 71 CF patients carrying 2 mutations known to be associated with severe disease presentation (delta F508, W1282X, G542X, N1303K, 1717-1G --> A). Group B: 10 compound heterozygous patients who carry one mutation associated with mild clinical disease (3849 + 10 kb --> T). Group C: 142 normal subjects. Sweat chloride levels higher than those of sodium were found in 96% of patients in Group A as compared to 3% of patients in Group C. In Group B 40% of the patients had sweat chloride levels higher than or equal to sodium levels. The mean Cl/Na ratio of Group A (1.2 +/- 0.1) differed significantly from that of Group B (0.94 +/- 0.1) and both groups had significant higher mean Cl/Na ratio compared to Group C (0.7 +/- 0.4) (P < 0.001). Thus in individuals with a borderline sweat test and a Cl/Na ratio > or = 1 the diagnosis of CF should be considered. However, a Cl/Na ratio < 1 does not exclude CF, since patients carrying mild mutations may have sweat sodium levels higher than those of chloride. Our findings suggest that the sweat Cl/Na ratio in CF is genetically determined and it may be of help in establishing the diagnosis of CF in patients with a borderline sweat test.


Assuntos
Cloretos/análise , Fibrose Cística/fisiopatologia , Sódio/análise , Suor/química , Criança , Fibrose Cística/genética , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Humanos , Mutação
18.
Phys Med Biol ; 43(9): 2479-89, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9755940

RESUMO

The effect of temperature on the optical properties of human dermis and subdermis as a function of near-infrared wavelength has been studied between 25 degrees C and 40 degrees C. Measurements were performed ex vivo on a total of nine skin samples taken from the abdomen of three individuals. The results show a reproducible effect of temperature on the transport scattering coefficient of dermis and subdermis. The relative change of the transport scattering coefficient showed an increase for dermis ((4.7+/-0.5) x 10(-3) degrees C(-1)) and a decrease for subdermis ((-1.4+/-0.28) x 10(-3) degrees C(-1)). Note that the magnitude of the temperature coefficient of scattering was greater for dermis than subdermis. A reproducible effect of temperature on the absorption coefficient could not be found within experimental errors. System reproducibility in transport scattering coefficient with repeated removal and repositioning of the same tissue sample at the same temperature was excellent at +/-0.35% for all measurements. This reproducibility enabled such small changes in scattering coefficient to be detected.


Assuntos
Derme/fisiologia , Fenômenos Fisiológicos da Pele , Fenômenos Biofísicos , Biofísica , Derme/efeitos da radiação , Humanos , Técnicas In Vitro , Raios Infravermelhos , Óptica e Fotônica/instrumentação , Espalhamento de Radiação , Temperatura Cutânea/fisiologia , Espectrofotometria Infravermelho
19.
Phys Med Biol ; 44(10): 2451-62, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10533922

RESUMO

The optical properties, absorption (mua) and reduced scattering coefficient (mu's), of ex vivo human myometrium and leiomyoma (fibroid) have been determined by the Monte Carlo inversion technique over the wavelength range 600-1000 nm. This region is currently of interest for new, minimal-access, surgical laser procedures such as photodynamic therapy (PDT) for abnormalities of the uterus, and interstitial laser photocoagulation (ILP) for the thermal ablation of fibroids. In the region 630-675 nm (corresponding to PDT), the optical coefficients of myometrium are mua = 0.041+/-0.012 mm(-1) and mu's = 1.37+/-0.19 mm(-1). For the wavelength range 800-1000 nm (associated with infrared lasers for ILP), the optical coefficients of fibroid were found to be mua = 0.020+/-0.003 mm(-1) and mu's = 0.56+/-0.03 mm(-1). Overall, the optical properties of fibroid were found to be lower than myometrium, and this was attributed to the differences in both anatomy and vascularity. The results show that PDT for ablation of the uterine endometrium is most unlikely to affect any tissues beyond the myometrium, and that the region around 800 nm is the most effective for ablation of fibroids using ILP as the penetration depth of light is greatest at this wavelength.


Assuntos
Leiomioma/diagnóstico , Miométrio/patologia , Espectrofotometria Infravermelho/métodos , Neoplasias Uterinas/diagnóstico , Útero/patologia , Adulto , Desenho de Equipamento , Feminino , Humanos , Fotocoagulação a Laser , Leiomioma/cirurgia , Pessoa de Meia-Idade , Miométrio/citologia , Espalhamento de Radiação , Espectrofotometria Infravermelho/instrumentação , Neoplasias Uterinas/cirurgia , Útero/citologia
20.
Phys Med Biol ; 46(10): 2515-30, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11686272

RESUMO

The absorption and reduced scattering coefficients of turbid tissue phantoms have been determined from photothermal measurements made using an optical fibre probe. The thermal sensor was a thin polymer film positioned at the end of a multimode optical fibre. The film was illuminated by the output of a continuous-wave diode laser and formed the cavity of a low-finesse Fabry-Perot interferometer. Low energy laser pulses, launched into the fibre and passed through the film, produced an abrupt temperature rise in the target tissue, which was placed in contact with the film. The subsequent conduction of heat into the film caused a change in its optical thickness and hence the reflected intensity. The absorption and reduced scattering coefficients of gelatine tissue phantoms of known optical properties were determined from the measurements using a numerical model of photothermal signal generation and maximum a posteriori estimation. The determined optical coefficients were in good agreement with the known values. The results showed that the probe can be used for the determination of optical coefficients provided the thermal coefficients of the target tissue are known with low uncertainty.


Assuntos
Imagens de Fantasmas , Radiometria/instrumentação , Radiometria/métodos , Gelatina , Temperatura Alta , Lasers , Método de Monte Carlo , Espalhamento de Radiação
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