Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 92
Filtrar
1.
AJNR Am J Neuroradiol ; 44(4): 424-433, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36927760

RESUMO

BACKGROUND AND PURPOSE: Superagers are defined as older adults with episodic memory performance similar or superior to that in middle-aged adults. This study aimed to investigate the key differences in discriminative networks and their main nodes between superagers and cognitively average elderly controls. In addition, we sought to explore differences in sensitivity in detecting these functional activities across the networks at 3T and 7T MR imaging fields. MATERIALS AND METHODS: Fifty-five subjects 80 years of age or older were screened using a detailed neuropsychological protocol, and 31 participants, comprising 14 superagers and 17 cognitively average elderly controls, were included for analysis. Participants underwent resting-state-fMRI at 3T and 7T MR imaging. A prediction classification algorithm using a penalized regression model on the measurements of the network was used to calculate the probabilities of a healthy older adult being a superager. Additionally, ORs quantified the influence of each node across preselected networks. RESULTS: The key networks that differentiated superagers and elderly controls were the default mode, salience, and language networks. The most discriminative nodes (ORs > 1) in superagers encompassed areas in the precuneus posterior cingulate cortex, prefrontal cortex, temporoparietal junction, temporal pole, extrastriate superior cortex, and insula. The prediction classification model for being a superager showed better performance using the 7T compared with 3T resting-state-fMRI data set. CONCLUSIONS: Our findings suggest that the functional connectivity in the default mode, salience, and language networks can provide potential imaging biomarkers for predicting superagers. The 7T field holds promise for the most appropriate study setting to accurately detect the functional connectivity patterns in superagers.


Assuntos
Giro do Cíngulo , Imageamento por Ressonância Magnética , Idoso , Pessoa de Meia-Idade , Humanos , Imageamento por Ressonância Magnética/métodos , Cognição , Córtex Pré-Frontal , Lobo Temporal , Mapeamento Encefálico/métodos , Encéfalo/diagnóstico por imagem
2.
Ann R Coll Surg Engl ; 105(3): 218-224, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35638904

RESUMO

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is an evolving problem with varied presentation. No definite treatment guidelines are available at present that may reduce rate of recurrence. Current evidence suggests a ductal pathology behind IGM, which leads to periductal mastitis, leakage and sinus/fistula formation. Thus, excision of the sinus/fistulous tract with en-bloc wide local excision (WLE) of the lesion could be curative. The objective of this study was to look for the basic aetiology of IGM and evaluate the effectiveness of WLE with total or partial duct excision as a curative approach. METHODS: An institutional prospective comparative study was conducted over 4 years (2015-2019), in which 59 cases of IGM were randomly divided into three groups. After necessary investigations, patients in group A received steroid therapy, those in group B received WLE and patients in group C received WLE with total or partial duct excision as the mode of treatment. Postoperative follow-up was between 6 months and 3 years. RESULTS: Histopathological examination (HPE) was found to be the most suitable diagnostic procedure. Patients in group B showed the highest rate of recurrence (73.6%), followed by group A (35.0%) and group C (5.0%). Patients in group C had a significantly lower chance of recurrence compared with both group A and group B (p < 0.05). HPE reports of excised ducts from patients in group C showed ductal disruption and leakage along with periductal granuloma in 70% of cases. CONCLUSIONS: The presence of duct granuloma indicates the association of ductal pathology in IGM. IGM is therefore a disease of the mammary ducts and en-bloc duct excision is curative in non-responding cases.


Assuntos
Mastite Granulomatosa , Feminino , Humanos , Mastite Granulomatosa/diagnóstico , Mastite Granulomatosa/cirurgia , Mastite Granulomatosa/patologia , Estudos Prospectivos , Granuloma , Imunoglobulina M
3.
Artigo em Inglês | MEDLINE | ID: mdl-34769832

RESUMO

This paper describes the functional development of the ClimApp tool (available for free on iOS and Android devices), which combines current and 24 h weather forecasting with individual information to offer personalised guidance related to thermal exposure. Heat and cold stress assessments are based on ISO standards and thermal models where environmental settings and personal factors are integrated into the ClimApp index ranging from -4 (extremely cold) to +4 (extremely hot), while a range of -1 and +1 signifies low thermal stress. Advice for individuals or for groups is available, and the user can customise the model input according to their personal situation, including activity level, clothing, body characteristics, heat acclimatisation, indoor or outdoor situation, and geographical location. ClimApp output consists of a weather summary, a brief assessment of the thermal situation, and a thermal stress warning. Advice is provided via infographics and text depending on the user profile. ClimApp is available in 10 languages: English, Danish, Dutch, Swedish, Norwegian, Hellenic (Greek), Italian, German, Spanish and French. The tool also includes a research functionality providing a platform for worker and citizen science projects to collect individual data on physical thermal strain and the experienced thermal strain. The application may therefore improve the translation of heat and cold risk assessments and guidance for subpopulations. ClimApp provides the framework for personalising and downscaling weather reports, alerts and advice at the personal level, based on GPS location and adjustable input of individual factors.


Assuntos
Temperatura Baixa , Tempo (Meteorologia) , Aclimatação , Previsões , Temperatura Alta , Humanos
4.
Mymensingh Med J ; 30(2): 415-419, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33830122

RESUMO

Gastrointestinal diseases frequently affect patients' physical and emotional wellbeing as being heavily affected by stress. This study was conducted to find out prevalence and severity of depressive symptoms among patients presenting with gastrointestinal symptoms. This cross sectional study was conducted at Outpatients Department jointly by Department of Gastroenterology and Department of Psychiatry of a tertiary care hospital in north east part of Bangladesh from November 2011 to June 2012. Consecutive patients with gastrointestinal symptoms underwent psychiatric evaluation using HDRS and analyzed. 442 patients, 38(8.6%) were found normal. Among the rest 128(28.96%), 138(31.22%), 72(16.29%) and 66(14.93%) had mild, moderate, severe and very severe depressive symptoms respectively. Female sex (95.03% vs. 89.32%), married people (93.77 vs. 86.13%), older age (98.24%), rural people (94.26% vs. 84.36%), farmers (96.36%) and house wives (96.24%) were more affected. Prevalence of depression was also higher among patients with lower socioeconomic class, less educated people and rural background. Depressive symptoms are very common in patients presenting with gastrointestinal symptoms. Awareness regarding psychiatric assessment and intervention may reduce sufferings and thus improve wellbeing of these patients.


Assuntos
Depressão , Gastroenteropatias , Idoso , Bangladesh/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Depressão/etiologia , Feminino , Gastroenteropatias/epidemiologia , Humanos , Prevalência
5.
SAR QSAR Environ Res ; 29(11): 911-933, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30332922

RESUMO

Multiple Quantitative Structure-Activity Relationship (QSAR) analysis is widely used in drug discovery for lead identification. Human Immunodeficiency Virus (HIV) protease is one of the key targets for the treatment of Acquired Immunodeficiency Syndrome (AIDS). One of the major challenges for the design of HIV-1 protease inhibitors (HIV PRIs) is to increase the inhibitory activities against the enzyme to a level where the problem associated to drug resistance may be considerably delayed. Herein, chemometric analyses were performed with 346 structurally diverse HIV PRIs with experimental bioactivities against a sub-type B mutant to develop highly predictable QSAR models and also to identify the effective structural determinants for higher affinity against HIV PR. The QSAR models were developed using OCHEM-based machine learning tools (ASNN, FSMLR, KNN, RF, MANN and XGBoost), with descriptors calculated by eight different software packages. Simultaneously, a Monte Carlo optimization-based QSAR modelling was performed using SMILES and graph-based descriptors to understand fragment and topochemical contributions. To validate the actual predictability of all these models, an additional set of 104 compounds (also with known experimental activities) with slightly different chemical space were employed. This ligand-based study serves as a crucial benchmark for further development of the HIV protease inhibitors with improved activities.


Assuntos
Inibidores da Protease de HIV/química , Inibidores da Protease de HIV/farmacologia , Protease de HIV/química , Relação Quantitativa Estrutura-Atividade , Protease de HIV/genética , Protease de HIV/metabolismo , Método de Monte Carlo
6.
Sci Rep ; 8(1): 6195, 2018 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-29670133

RESUMO

Iron impurity in raw material remains a major challenge in producing colourless glass. In this investigation, we report microwave (MW) heating capable of altering Fe-redox ratio (Fe2+/∑Fe) enabling preparation of colourless phosphate glass. The effect of Sn concentration in retention of Fe[II] in glass melted in MW was compared with conventional glasses. Colourimetric study developing Fe2+-ferrozine colour complex reveals Fe-redox ratio ≥0.49 required to obtain colourless phosphate glass. In microwave heating, addition of 1 wt.% Sn metal powder can impart the desired effect whereas addition of 1.9 wt.% Sn metal powder is required in conventional heating. The correlation equation of Fe-redox ratio with concentration of Sn metal is found to be different in microwave and conventional heating. Thus, exploiting this different redox changes in MW heating optical properties can be tailored. Preservation of higher Fe[II] in MW melted glass is also confirmed by XPS and TGA. 31P MAS NMR spectra suggest that transition from cross linked ultra phosphate to linear polymer metaphosphate network in incorporation of Sn is found different in glass prepared adopting microwave irradiation. 27A1 MAS NMR spectra suggest higher relative content of Al6+ in glass obtained from MW heating. Energy consumption analysis revels 3.4 kWh in MW heating while 14 kWh in conventional glass melting using resistance heating. Further, glass melting in MW can be completed within 2 h unlike ~5 h needed in conventional. MW heating plays a significant role in improving properties to make colourless phosphate glass in addition to significant energy and time saving.

7.
Andrologia ; 50(2)2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28836280

RESUMO

The dicentric Y chromosome is the most common cytogenetically visible structural abnormality of Y chromosome. The sites of break and fusion of dicentric Y are variable, but break and fusion at Yq12 (proximal to the pseudoautosomal region 2/PAR 2) is very rare. Dicentric Y chromosome is unstable during cell division and likely to generate chromosomal mosaicism. Here, we report a case of infertile male with nonmosaic 46,XY where chromosome Y was dicentric with break and fusion at Yq12 (proximal to PAR 2). Clinical presentation of the case was nonobstructive azoospermia due to early maturation arrest at the primary spermatocyte stage. Various molecular techniques such as FISH, STS-PCR and DNA microarray were carried out to characterise genetic defect leading to testicular maturation arrest in the patient. The break and fusion was found at Yq12 (proximal to PAR 2) and resulted in near total duplication of Y chromosome (excluding PAR 2). The reason for maturation arrest seems due to CNVs of PARs (gain in PAR 1 and loss of PAR 2) and azoospermia factors (gain).


Assuntos
Azoospermia/genética , Cromossomos Humanos Y/genética , Infertilidade Masculina/genética , Transtornos dos Cromossomos Sexuais/genética , Maturação do Esperma/genética , Adulto , Azoospermia/diagnóstico , Azoospermia/patologia , Biópsia por Agulha Fina , Humanos , Infertilidade Masculina/diagnóstico , Infertilidade Masculina/patologia , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Regiões Pseudoautossômicas/genética , Transtornos dos Cromossomos Sexuais/diagnóstico , Transtornos dos Cromossomos Sexuais/patologia , Testículo/patologia
8.
SAR QSAR Environ Res ; 28(3): 253-273, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28322591

RESUMO

Schizophrenia is a complex disorder of thinking and behaviour (0.3-0.7% of the population is affected). The over-expression of phosphodiesterase 10A (PDE10A) enzyme may be a potential target for schizophrenia and Huntington's disease. Because 3D QSAR analysis is one of the most frequently used modelling techniques, in the present study, five different 3D QSAR tools, namely CoMFA, CoMSIA, kNN-MFA, Open3DQSAR and topomer CoMFA methods, were used on a dataset of pyrimidine-based PDE10A inhibitors. All developed models were validated internally and externally. The non-commercial Open3DQSAR produced the best statistical results amongst 3D QSAR tools. The structural interpretations obtained from different methods were thoroughly analysed and were justified on the basis of information obtained from the crystal structure. Information from one method was mostly validated by the results of other methods and vice versa. In the current work, the use of multiple tools in the same analysis revealed more complete information about the structural requirements of these compounds. On the basis of the observations of the 3D QSAR studies, 12 new compounds were designed for better PDE10A inhibitory activity. The current investigation may help in further designing new PDE10A inhibitors with promising activity.


Assuntos
Inibidores de Fosfodiesterase/química , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Pirimidinas/química , Pirimidinas/farmacologia , Relação Quantitativa Estrutura-Atividade , Diester Fosfórico Hidrolases/química
9.
Andrology ; 5(3): 460-472, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28217965

RESUMO

Testicular maturation arrest is characterized by interruption of germ cell development and differentiation. Genetic factors play important role in the causation of human disease, including male infertility. The objective was to study copy number variations in testicular maturation arrest using single nucleotide polymorphism (SNP) microarray technique. Conventional cytogenetics, targeted fluorescence in situ hybridization (FISH) and sequence-tagged site (STS) polymerase chain reaction (PCR) were used to confirm some of the SNP microarray findings. SNP microarray on 68 cases of testicular maturation arrest detected copy number variations (CNVs) mostly on sex chromosomes involving pseudoautosomal regions (PAR) 1, 2 and 3 as well as azoospermic factors (AZFs) besides three cases of chromosomal abnormalities (two Klinefelter syndromes and one case of dicentric Y). The AZF deletion was observed in 14 (20.6%) cases and the AZFc gain was observed in 6 (8.8%) cases. PAR 1 and 2 CNVs was observed in 5 (7.3%) cases. PAR 3 CNVs was detected in 19 cases and 2 controls. The TSPY2 gene gain (within PAR 3 CNVs) was observed in 16 cases and 1 control. CNV containing autosomal genes possibly associated with male infertility in this study was SPATA31A2-A5 (9p12) in five cases. In this study, SNP microarray identified possible underlying aetiology in 55.9% (38/68) cases besides identifying minimal critical region of AZFc deletion as 0.51 mb (Y:24356128-24873665) involving TTY5, RBMY2FP, RBMY1F, RBMY1J, TTY6 and PRY genes. SNP microarray seems superior, sensitive, specific as well as cost-effective method and has potential to be the first tier investigations to explore underlying genomic factors of testicular maturation arrest. The present study is an attempt to find out probable genomic factors with idiopathic testicular maturation arrest.


Assuntos
Azoospermia/congênito , Variações do Número de Cópias de DNA/genética , Infertilidade Masculina/genética , Adolescente , Adulto , Azoospermia/genética , Humanos , Hibridização in Situ Fluorescente , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Adulto Jovem
10.
J Hosp Infect ; 94(3): 286-294, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27665311

RESUMO

BACKGROUND: Healthcare facility hand hygiene impacts patient care, healthcare worker safety, and infection control, but low-income countries have few data to guide interventions. AIM: To conduct a nationally representative survey of hand hygiene infrastructure and behaviour in Bangladeshi healthcare facilities to establish baseline data to aid policy. METHODS: The 2013 Bangladesh National Hygiene Baseline Survey examined water, sanitation, and hand hygiene across households, schools, restaurants and food vendors, traditional birth attendants, and healthcare facilities. We used probability proportional to size sampling to select 100 rural and urban population clusters, and then surveyed hand hygiene infrastructure in 875 inpatient healthcare facilities, observing behaviour in 100 facilities. FINDINGS: More than 96% of facilities had 'improved' water sources, but environmental contamination occurred frequently around water sources. Soap was available at 78-92% of handwashing locations for doctors and nurses, but just 4-30% for patients and family. Only 2% of 4676 hand hygiene opportunities resulted in recommended actions: using alcohol sanitizer or washing both hands with soap, then drying by air or clean cloth. Healthcare workers performed recommended hand hygiene in 9% of 919 opportunities: more after patient contact (26%) than before (11%). Family caregivers frequently washed hands with only water (48% of 2751 opportunities), but with little soap (3%). CONCLUSION: Healthcare workers had more access to hand hygiene materials and performed better hand hygiene than family, but still had low adherence. Increasing hand hygiene materials and behaviour could improve infection control in Bangladeshi healthcare facilities.


Assuntos
Atitude do Pessoal de Saúde , Cuidadores , Higiene das Mãos/métodos , Instalações de Saúde , Pessoal de Saúde , Controle de Infecções/métodos , Controle de Infecções/organização & administração , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Bangladesh , Criança , Pré-Escolar , Infecção Hospitalar/prevenção & controle , Países em Desenvolvimento , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Gravidez , Adulto Jovem
11.
Transpl Infect Dis ; 16(5): 713-23, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25200928

RESUMO

INTRODUCTION: Cytomegalovirus (CMV) and human adenovirus (ADV) infections are causes of morbidity after stem cell transplantation. Antigen (Ag)-specific T cells are essential for the control of viral infections. However, in vivo expansion potential of T-cell subpopulations is hardly predictable in humans. Furthermore, ex vivo identification of human T cells with repopulating capacity for adoptive T-cell transfer has been difficult. METHODS: We analyzed Ag-specific T-cell populations, subdivided according to the expression of different THELPER- 1 (Th1) cytokines. Isolation by flow cytometry was based on interferon-gamma (IFN)-γ, interleukin (IL)-2, or tumor necrosis factor-alpha (TNF-α) secretion of T cells after ex vivo stimulation with the Ags hexon (for ADV) and pp65 (for CMV). Isolated T cells were expanded and examined for functional characteristics, expansion/differentiation potential, and naïve, effector memory, central memory, and late effector phenotypes. RESULTS: Isolation based on IFN-γ production provides a T-cell population with a mixture of early, central memory, and effector memory T cells, high expansion potential, and effective cytokine production. Selection of T cells with Ag-specific expression of IL-2 or TNF-α, however, results in a T-cell population with reduced proliferation and lower effector potential after expansion. CONCLUSION: We conclude that the exclusive secretion of IFN-γ in the human antiviral T-cell responses preferentially leads to higher repopulation capacities of antiviral T cells, compared to IL-2 or TNF-α secreting T-cell populations.


Assuntos
Linfócitos T CD8-Positivos , Interferon gama/metabolismo , Interleucina-2/metabolismo , Células Th1/imunologia , Células Th1/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Imunidade Adaptativa , Linfócitos T CD8-Positivos/química , Proteínas do Capsídeo/imunologia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Humanos , Memória Imunológica , Interferon gama/análise , Interleucina-2/análise , Selectina L/análise , Antígenos Comuns de Leucócito/análise , Contagem de Linfócitos , Fosfoproteínas/imunologia , Células Th1/química , Fator de Necrose Tumoral alfa/análise , Proteínas da Matriz Viral/imunologia
12.
Appl Opt ; 53(4): 555, 2014 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-24514171

RESUMO

Jung and Lee have made comments [Appl. Opt.53, 553-554 (2014)] on "Mode-locked thulium bismuth codoped fiber laser using Graphene saturable absorber in ring cavity" [Appl. Opt.52, 1226-1229 (2013)]. The answer for the comment is provided in this report.

13.
Andrologia ; 46(3): 316-21, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23445433

RESUMO

Dark-coloured semen is rarely observed in men with nonobstructive azoospermia in absence of genital tract bleeding. Dark-coloured semen is also observed rarely in men with spinal cord injury with or without genital tract bleeding. However, this condition has not been reported in the literature in absence of genital tract bleeding or spinal cord injury. Here, we report men with nonobstructive azoospermia with dark-coloured semen and without genital tract bleeding or spinal cord injury. The study included four subjects with dark-coloured semen. All the samples first investigated for the presence of red blood cells as well as haemoglobin. All the cases were examined in details with seminal, hormonal and genetic parameters. In addition, an elemental electron microscopy and inductively coupled plasma-atomic emission spectrometry evaluation for heavy metals was performed. The semen parameters showed normal volume, pH, leucocyte count and azoospermia or oligoazoospermia. Dark-coloured semen specimens contained neither red blood cells nor haeme pigment. Electron microscopy showed presence of platinum in all the cases, whereas inductively coupled plasma-atomic emission spectrometry revealed increased levels of lead, manganese and nickel in serum as compared to controls. The results indicate dark-coloured semen may be linked with heavy metals found in seminal cells.


Assuntos
Azoospermia/metabolismo , Metais Pesados/metabolismo , Sêmen/metabolismo , Adulto , Azoospermia/patologia , Estudos de Casos e Controles , Cor , Humanos , Masculino , Microscopia Eletrônica de Varredura , Sêmen/citologia , Análise do Sêmen , Espectrofotometria Atômica
14.
Appl Opt ; 52(6): 1226-9, 2013 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-23434993

RESUMO

We demonstrate mode locking of a thulium-bismuth codoped fiber laser (TBFL) operating at 1901.6 nm, using a graphene-based saturable absorber (SA). In this work, a single layer graphene is mechanically exfoliated using the scotch tape method and directly transferred onto the surface of a fiber pigtail to fabricate the SA. The obtained Raman spectrum characteristic indicates that the graphene on the core surface has a single layer. At 1552 nm pump power of 869 mW, the mode-locked TBFL self starts to generate an optical pulse train with a repetition rate of 16.7 MHz and pulse width of 0.37 ps. This is a simple, low-cost, stable, and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.


Assuntos
Técnicas Biossensoriais , Bismuto/química , Túlio/química , Absorção , Desenho de Equipamento , Grafite/química , Lasers , Fibras Ópticas , Oscilometria/métodos , Análise Espectral Raman/métodos , Propriedades de Superfície , Fatores de Tempo
15.
Appl Opt ; 51(16): 3445-52, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22695582

RESUMO

The core-mode cutoff plays a major role in evanescent field absorption based sensors. A method has been proposed to calculate the core-mode cutoff by solving the eigenvalue equations of a weakly guiding three layer optical waveguide graphically. The variation of normalized waveguide parameter (V) is also calculated with different wavelengths at core-mode cutoff. At the first step, theoretical analysis of tapered fiber parameters has been performed for core-mode cutoff. The taper angle of an adiabatic tapered fiber is also analyzed using the length-scale criterion. Secondly, single-mode tapered fiber has been developed to make a precision sensor element suitable for chemical detection. Finally, the sensor element has been used to detect absorption peak of ethylenediamine. Results are presented in which an absorption peak at 1540 nm is observed.


Assuntos
Tecnologia de Fibra Óptica/instrumentação , Miniaturização/instrumentação , Fibras Ópticas , Espectrofotometria/instrumentação , Algoritmos , Desenho de Equipamento , Etilenodiaminas/análise , Tecnologia de Fibra Óptica/métodos , Modelos Teóricos
16.
Clin Biomech (Bristol, Avon) ; 27(7): 711-8, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22633130

RESUMO

BACKGROUND: Following surgery or injury of the lower limbs, the use of walking aids like crutches can cause high loads on the shoulder joint. These loads have been calculated so far with computer models but with strongly varying results. METHODS: Shoulder joint forces and moments were measured during crutch-assisted walking with complete and partial unloading of the lower limbs. Using telemeterized implants in 6 subjects axillary crutches and forearm crutches were compared. A force direction was more in the direction of the long humeral axis, and slightly lower forces were assumed using axillary crutches. Similar force magnitudes as those experienced during previously measured wheelchair weight relief tasks were expected for complete unloading. The friction-induced moment was hypothesized to act mainly around the medio-lateral axis during the swing phase of the body. FINDINGS: Maximum loads of up 170% of the bodyweight and 0.8% of the bodyweight times meter were measured with large variations among the patients. Higher forces were found in most of the patients using forearm crutches. The hypothesized predominant moment around the medio-lateral axis was only found in some patients. More often, the other two moments had larger magnitudes with the highest values in female patients. The assumed different load direction could only be found during partial unloading. INTERPRETATION: In general the force magnitudes were in the range of activities of daily living. However, the number of repetitions during long-lasting crutch use could lead to shoulder problems as a long-term consequence. The slightly lower forces with axillary crutches could be caused by loads acting directly from the crutch on the scapula, thus bypassing the glenohumeral joint. The higher bending moments in the female patients could be a sign of lacking muscle strength for centring the humeral head on the glenoid.


Assuntos
Muletas , Transtornos Neurológicos da Marcha/fisiopatologia , Transtornos Neurológicos da Marcha/reabilitação , Monitorização Ambulatorial/instrumentação , Osteoartrite/fisiopatologia , Osteoartrite/reabilitação , Articulação do Ombro/fisiopatologia , Idoso , Desenho de Equipamento , Análise de Falha de Equipamento , Feminino , Transtornos Neurológicos da Marcha/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Osteoartrite/complicações , Estresse Mecânico , Transdutores de Pressão , Suporte de Carga
17.
Oper Orthop Traumatol ; 24(2): 85-94, 2012 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-22373790

RESUMO

OBJECTIVE: Tibial tubercle osteotomy facilitates access to the knee joint without excessive tension of the extensor apparatus with the lateral parapatellar approach and the medial parapatellar approach in case of contracture or revision arthroplasty. INDICATIONS: Inadequate exposure of the knee joint with the lateral parapatellar approach and inadequate exposure of the knee joint with the medial parapatellar approach in case of contracture and revision arthroplasty. CONTRAINDICATIONS: Severe periarticular osteoporosis or bone atrophy after knee arthroplasty and damage to the patella tendon insertion due to previous operations. SURGICAL TECHNIQUE: A bone block 8-10 cm long is excised with the tibial tubercle using an oscillating saw. A step cut inferior to the tibial plateau is created with a chisel. Refixation is performed with two cortical screws. Alternatively, in case of poor bone quality, refixation is accomplished with two cerclage wires. POSTOPERATIVE MANAGEMENT: In case of stable refixation, full weight bearing is allowed with an extension brace for 2-4 weeks and passive flexion is increased as tolerated. In case of poor bone quality, it is recommended that full weight bearing be postponed for 6 weeks, whereby full flexion is regained in 30° steps at 2, 4, and 6 weeks postoperatively. RESULTS: From 2001-2004, 67 osteotomies of the tibial tubercle were performed for revision arthroplasty. During follow-up in 2010, no pseudarthrosis or dislocation was noticed. Postoperatively, two hematoma and one skin necrosis had to be revised. The risk of hematoma and pseudarthrosis or dislocation of the fragment can be minimized by using the correct operative technique.


Assuntos
Artroplastia do Joelho/instrumentação , Artroplastia do Joelho/métodos , Instabilidade Articular/cirurgia , Prótese do Joelho , Osteotomia/instrumentação , Osteotomia/métodos , Tíbia/cirurgia , Idoso , Feminino , Humanos , Instabilidade Articular/diagnóstico , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
18.
Clin Biomech (Bristol, Avon) ; 26(10): 982-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21719168

RESUMO

BACKGROUND: Recent in vivo measurements show that the loads acting in the glenohumeral joint are high even during activities of daily living. Wheelchair users are frequently affected by shoulder problems. With previous musculoskeletal shoulder models, shoulder joint loading was mostly calculated during well-defined activities like forward flexion or abduction. For complex movements of everyday living or wheelchair propulsion, the reported loads vary considerably. METHODS: Shoulder joint forces and moments were measured with telemeterized implants in 6 subjects. Data were captured on a treadmill at defined speeds and inclinations. Additional measurements were taken in 1 subject when lifting the body from the wheelchair, using his arms only, and in 2 subjects when rapidly accelerating and stopping the wheelchair. The influence of the floor material on shoulder joint loading was accessed in 2 subjects. In general, the maximum shoulder loads did not exceed those during daily living but the time courses and magnitudes of the loads intra-individually varied much. FINDINGS: The highest forces acted during maximum acceleration and lifting from the wheelchair (128% and 188% of body weight). Grass was the only surface which led to a general load increase, compared to a smooth floor. INTERPRETATION: The increased incidence of overuse injuries in wheelchair users are probably not caused by excessive load magnitudes during regular propulsion. The high number of repetitions is assumed to be more decisive.


Assuntos
Articulação do Ombro/fisiologia , Cadeiras de Rodas , Aceleração , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Desenho de Equipamento , Humanos , Remoção , Pessoa de Meia-Idade , Telemetria/instrumentação
19.
J Biomech ; 44(8): 1543-52, 2011 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-21481879

RESUMO

To improve design and preclinical test scenarios of shoulder joint implants as well as computer-based musculoskeletal models, a precise knowledge of realistic loads acting in vivo is necessary. Such data are also helpful to optimize physiotherapy after joint replacement and fractures. This is the first study that presents forces and moments measured in vivo in the gleno-humeral joint of 6 patients during forward flexion and abduction of the straight arm. The peak forces and, even more, the maximum moments varied inter-individually to a considerable extent. Forces of up to 238%BW (percent of body weight) and moments up to 1.74%BWm were determined. For elevation angles of less than 90° the forces agreed with many previous model-based calculations. At higher elevation angles, however, the measured loads still rose in contrast to the analytical results. When the exercises were performed at a higher speed, the peak forces decreased. The force directions relative to the humerus remained quite constant throughout the whole motion. Large moments in the joint indicate that friction in shoulder implants is high if the glenoid is not replaced. A friction coefficient of 0.1-0.2 seems to be realistic in these cases.


Assuntos
Artroplastia de Substituição/métodos , Úmero/anatomia & histologia , Prótese Articular , Articulação do Ombro/anatomia & histologia , Idoso , Idoso de 80 Anos ou mais , Fenômenos Biomecânicos , Feminino , Humanos , Úmero/patologia , Masculino , Teste de Materiais , Pessoa de Meia-Idade , Movimento , Amplitude de Movimento Articular , Escápula , Software , Estresse Mecânico , Telemetria/métodos , Resistência à Tração
20.
Unfallchirurg ; 113(8): 635-40, 2010 Aug.
Artigo em Alemão | MEDLINE | ID: mdl-20668830

RESUMO

PURPOSE: Problems related to the use of interference screws for fixation of bone-patellar tendon-bone grafts for anterior cruciate ligament (ACL) replacement have led to increasing interest in press-fit techniques. Most of the described techniques use press-fit fixation on either the femoral or tibial side. Therefore an arthroscopic technique was developed which achieves bone-patellar tendon-bone graft fixation by press-fit on both sides without the need for supplemental fixation material. METHODS: The first consecutive 40 patients were examined clinically with a KT-1000 arthrometer and radiologically after a mean of 28.7 months (range 20-40 months) postoperatively. RESULTS: The mean difference in side-to-side laxity was 1.3 mm (SD 2.2 mm) and the results according to the International Knee Documentation Committee (IKDC) score were as follows: 7 A, 28 B, 5 C, 0 D. CONCLUSIONS: The presented press-fit technique avoids all complications related to the use of interference screws. It achieves primary stable fixation of the bone-patellar tendon-bone graft thereby allowing early functional rehabilitation. However, fixation strength depends on bone quality and the arthroscopic procedure is demanding. The results showed reliable stabilization of the operated knees.


Assuntos
Lesões do Ligamento Cruzado Anterior , Ligamento Cruzado Anterior/cirurgia , Artroscopia/métodos , Parafusos Ósseos , Traumatismos do Joelho/cirurgia , Âncoras de Sutura , Transferência Tendinosa/métodos , Adolescente , Adulto , Ligamento Cruzado Anterior/fisiopatologia , Feminino , Humanos , Instabilidade Articular/fisiopatologia , Instabilidade Articular/prevenção & controle , Traumatismos do Joelho/fisiopatologia , Masculino , Pessoa de Meia-Idade , Terapia Passiva Contínua de Movimento , Cuidados Pós-Operatórios , Complicações Pós-Operatórias/fisiopatologia , Complicações Pós-Operatórias/prevenção & controle , Amplitude de Movimento Articular/fisiologia , Estudos Retrospectivos , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...