427 research outputs found
Fluorescent probes of the orientation of myosin regulatory light chains in relaxed, rigor, and contracting muscle.
The orientation of the light-chain region of myosin heads in relaxed, rigor, and isometrically contracting fibers from rabbit psoas muscle was studied by fluorescence polarization. Cysteine 108 of chicken gizzard myosin regulatory light chain (cgRLC) was covalently modified with iodoacetamidotetramethylrhodamine (iodo-ATR). Native RLC of single glycerinated muscle fibers was exchanged for labeled cgRLC in a low [Mg2+] rigor solution at 30 degrees C. Troponin and troponin C removed in this procedure were replaced. RLC exchange had little effect on active force production. X-ray diffraction showed normal structure in rigor after RLC exchange, but loss of axial and helical order in relaxation. In isolated myofibrils labeled cgRLC was confined to the regions of the sarcomere containing myosin heads. The ATR dipoles showed a preference for orientations perpendicular to the fiber axis, combined with limited nanosecond rotational motion, in all conditions studied. The perpendicular orientation preference was more marked in rigor than in either relaxation or active contraction. Stretching relaxed fibers to sarcomere length 4 microns to eliminate overlap between actin- and myosin-containing filaments had little effect on the orientation preference. There was no change in orientation preference when fibers were put into rigor at sarcomere length 4.0 microns. Qualitatively similar results were obtained with ATR-labeled rabbit skeletal RLC
Estudo antropométrico, clínico e de padrões alimentares em um grupo de escolares de Manaus, 1976
A group of 69 children in the first year of a State School in a poor area of urban Manaus, Amazonas, was subjected to clinical, anthropometric and dietary studies. Eighty-five percent of the children were malnourished when compared by height and/or weight to the Harvard Growth Pattern. Clinical evidence of anaemia and Vitamin A deficiencies were high. The frequency of end of the first year exam failure was higher in malnourished children. The food pattern seemed good from a qualitatively point of view but referred to Sunday. The school children were regular beneficiaries of the National School Snack Campaign (CNAE).Exame físico, medidas antropométricas e padrões alimentares foram obtidos em um grupo de 69 escolares na primeira série do primeiro ciclo escolar de Manaus. O estudo foi realizado numa escola localizada e recebendo crianças de um bairro pobre da cidade. As crianças estavam recebendo merenda escolar. Alto índice de desnutrição foi encontrado, acompanhado de sinais de anemia e provável carência de Vitamina A. A incidência de cáries dentárias também foi elevada. Freqüência elevada de reprovações foi encontrada e suas prováveis correlações com o estado nutricional estabelecidas. O padrão alimentar, mesmo considerando ser um domingo, parece bom qualititavamente, salientando-se a presença da farinha de mandioca como básica em todos os cardápios
Craniofacial identification standards: a review of reliability, reproducibility, and implementation
There are numerous anatomical and anthropometrical standards that can be utilised for craniofacial analysis and identification. These standards originate from a wide variety of sources, such as orthodontic, maxillofacial, surgical, anatomical, anthropological and forensic literature, and numerous media have been employed to collect data from living and deceased subjects. With the development of clinical imaging and the enhanced technology associated with this field, multiple methods of data collection have become accessible, including Computed Tomography, Cone-Beam Computed Tomography, Magnetic Resonance Imaging, Radiographs, Three-dimensional Scanning, Photogrammetry and Ultrasound, alongside the more traditional in vivo methods, such as palpation and direct measurement, and cadaveric human dissection. Practitioners often struggle to identify the most appropriate standards and research results are frequently inconsistent adding to the confusion. This paper aims to clarify how practitioners can choose optimal standards, which standards are the most reliable and when to apply these standards for craniofacial identification. This paper describes the advantages and disadvantages of each mode of data collection and collates published research to review standards across different populations for each facial feature. This paper does not aim to be a practical instruction paper; since this field encompasses a wide range of 2D and 3D approaches (e.g., clay sculpture, sketch, automated, computer-modelling), the implementation of these standards is left to the individual practitioner
TLR-mediated activation of Waldenström macroglobulinemia B cells reveals an uncoupling from plasma cell differentiation
Waldenstr¨om macroglobulinemia (WM) is a rare malignancy in which clonal B cells infiltrate the bone marrow and give rise to a smaller compartment of neoplastic plasma cells that secrete monoclonal immunoglobulin M paraprotein. Recent studies into underlying mutations in WM have enabled a much greater insight into the pathogenesis of this lymphoma. However, there is considerably less characterization of the way in which WM B cells differentiate and how they respond to immune stimuli. In this study, we assess WM B-cell differentiation using an established in vitro model system. Using T-cell–dependent conditions, we obtained CD1381 plasma cells from WM samples with a frequency similar to experiments performed with B cells from normal donors. Unexpectedly, a proportion of the WM B cells failed to upregulate CD38, a surface marker that is normally associated with plasmablast transition and maintained as the cells proceed with differentiation. In normal B cells, concomitant Toll-like receptor 7 (TLR7) activation and B-cell receptor cross-linking drives proliferation, followed by differentiation at similar efficiency to CD40-mediated stimulation. In contrast, we found that, upon stimulation with TLR7 agonist R848, WM B cells failed to execute the appropriate changes in transcriptional regulators, identifying an uncoupling of TLR signaling from the plasma cell differentiation program. Provision of CD40L was sufficient to overcome this defect. Thus, the limited clonotypic WM plasma cell differentiation observed in vivo may result from a strict requirement for integrated activation
Facial Reconstruction: Anthropometric Studies Regarding the Morphology of the Nose for Romanian Adult Population I: Nose Width
Craniofacial reconstruction often represents a final step in medico-legal identification and is dependent on facial tissue thickness measurements and feature shape estimation. This study’s aim is to create a reliable and readily reproductible method of predicting the maximum nose width (MNW) based on the maximum nasal aperture width (MAW) for a Romanian adult population. A sample of 55 computer tomography (CT) scans consisting of Romanian adult subjects was selected from the database of a neurosurgery hospital. The craniometrics measured consisted of a first measure of MAW and second one of the MNW using 3D systems Freeform Modelling Plus Software. Correlation analysis indicated a moderate link between the MAW and the MNW. Regression analysis showed that MAW and sex form a statistically significant regression pattern (R2 = 0.340, SEE (Standard Error of Estimate) = 3.801). The preliminary results obtained provide reliable predictions of MNW for facial reconstruction based on MAW measured on the skull
Cohort study of Western Australia computed tomography utilisation patterns and their policy implications
Background: Computed tomography (CT) scanning is a relatively high radiation dose diagnostic imaging modality with increasing concerns about radiation exposure burden at the population level in scientific literature. This study examined the epidemiology of adult CT utilisation in Western Australia (WA) in both the public hospital and private practice settings, and the policy implications. Methods: Retrospective cohort design using aggregate adult CT data from WA public hospitals and Medical Benefits Schedule (MBS) (mid-2006 to mid-2012). CT scanning trends by sex, age, provider setting and anatomical areas were explored using crude CT scanning rates, age-standardised CT scanning rates and Poisson regression modelling. Results: From mid-2006 to mid-2012 the WA adult CT scanning rate was 129 scans per 1,000 person-years (PY). Females were consistently scanned at a higher rate than males. Patients over 65 years presented the highest scanning rates (over 300 scans per 1,000 PY). Private practice accounted for 73% of adult CT scans, comprising the majority in every anatomical area. In the private setting females predominately held higher age-standardised CT scanning rates than males. This trend reversed in the public hospital setting. Patients over 85 years in the public hospital setting were the most likely age group CT scanned in nine of ten anatomical areas. Patients in the private practice setting aged 85+ years were relatively less prominent across every anatomical area, and the least likely age group scanned in facial bones and multiple areas CT scans.Conclusion: In comparison to the public hospital setting, the MBS subsidised private sector tended to service females and relatively younger patients with a more diverse range of anatomical areas, constituting the majority of CT scans performed in WA. Patient risk and subsequent burden is greater for females, lower ages and some anatomical areas. In the context of a national health system, Australia has various avenues to monitor radiation exposure levels, improve physician training and modify funding mechanisms to ensure individual and population medical radiation exposure is as low as reasonably achievable
First records of Baetis vernus Curtis (Ephemeroptera: Baetidae) in North America, with morphological notes
The Baetis vernus group (Ephemeroptera: Baetidae) – which includes B. brunneicolor McDunnough, B. bundyae Lehmkuhl, B. hudsonicus Ide, B. jaervii Savolainen, B. liebenauae Keffermüller, B. macani Kimmins, B. subalpinus Bengtsson, B. tracheatus Keffermüller & Machel, and B. vernus Curtis – is both diverse and taxonomically tangled. Some members of the group – B. brunneicolor, B. bundyae, and B. hudsonicus – have been previously found in North America. The remainder of the group is known to be only of Palearctic distribution, including B. vernus, which has a wide trans-Palearctic distribution. We report the collection of specimens from the Northwest Territories and British Columbia that we have identified as B. vernus using DNA barcoding and morphological examination and provide characters to assist separation of the North American members of the group from B. vernus. A genetically cohesive Holarctic clade for B. vernus likely relates to a Beringian dispersal event. This substantial expansion of the known range of B. vernus adds new phylogeographic and ecological complexity, but it may also help to provide further clues to the evolutionary history of this group
Radiological staging in breast cancer: which asymptomatic patients to image and how.
BACKGROUND: Approximately 4% of patients diagnosed with early breast cancer have occult metastases at presentation. Current national and international guidelines lack consensus on whom to image and how. METHODS: We assessed practice in baseline radiological staging against local guidelines for asymptomatic newly diagnosed breast cancer patients presenting to the Cambridge Breast Unit over a 9-year period. RESULTS: A total of 2612 patients were eligible for analysis; 91.7% were appropriately investigated. However in the subset of lymph node negative stage II patients, only 269 out of 354 (76.0%) investigations were appropriate. No patients with stage 0 or I disease had metastases; only two patients (0.3%) with stage II and or =4 positive lymph nodes), III and IV disease, respectively. CONCLUSION: These results prompted us to propose new local guidelines for staging asymptomatic breast cancer patients: only clinical stage III or IV patients require baseline investigation. The high specificity and convenience of computed tomography (chest, abdomen and pelvis) led us to recommend this as the investigation of choice in breast cancer patients requiring radiological staging
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