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1.
AJR Am J Roentgenol ; 213(4): 875-879, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31386570

RESUMO

OBJECTIVE. As patients increasingly turn to the Internet for healthcare information, it is imperative that patient educational materials be written at an appropriate readability level. Although RadiologyInfo.org, a patient education library sponsored by the American College of Radiology (ACR) and Radiological Society of North America, was shown in 2012 to be written at levels too high for the average patient to adequately comprehend, it is unclear if there has been progress made in the past 5 years. The purpose of this study was to provide a 5-year update on the readability of patient education materials from RadiologyInfo.org. MATERIALS AND METHODS. All patient education articles available in 2017 from the ACR and RSNA-sponsored RadiologyInfo.org patient education library were reviewed. We assessed each article for readability using 6 quantitative readability scales: the Flesch-Kincaid (FK) grade level, Flesch Reading Ease, Gunnin-Fog Index, Coleman-Liau Index, Automated Readability Index, and the Simple Measure of Gobbledygook (SMOG). The number of articles with readability ≤ the 8th grade level (average reading ability of US adults) and the 6th-grade level (NIH-recommended level for patient materials) were determined. RESULTS. 131 patient education articles were reviewed. The mean readability grade level was greater than the 11th grade reading level for all readability scales. None of the articles were written at less than the 8th-grade or the 6th-grade levels. CONCLUSION. Although there has been an increasing awareness of the issue of readability of patient educational materials within the radiological community, the patient educational materials within the ACR and RSNA-sponsored RadiologyInfo.org website are still written at levels too high for the average patient. Future efforts should be made to improve the readability of those patient education materials.


Assuntos
Informação de Saúde ao Consumidor , Letramento em Saúde , Internet , Radiologia , Humanos
2.
Br J Anaesth ; 123(2): 135-150, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31255291

RESUMO

Surgery is an important treatment modality for the majority of solid organ cancers. Unfortunately, cancer recurrence following surgery of curative intent is common, and typically results in refractory disease and patient death. Surgery and other perioperative interventions induce a biological state conducive to the survival and growth of residual cancer cells released from the primary tumour intraoperatively, which may influence the risk of a subsequent metastatic disease. Evidence is accumulating that anaesthetic and analgesic interventions could affect many of these pathophysiological processes, influencing risk of cancer recurrence in either a beneficial or detrimental way. Much of this evidence is from experimental in vitro and in vivo models, with clinical evidence largely limited to retrospective observational studies or post hoc analysis of RCTs originally designed to evaluate non-cancer outcomes. This narrative review summarises the current state of evidence regarding the potential effect of perioperative anaesthetic and analgesic interventions on cancer biology and clinical outcomes. Proving a causal link will require data from prospective RCTs with oncological outcomes as primary endpoints, a number of which will report in the coming years. Until then, there is insufficient evidence to recommend any particular anaesthetic or analgesic technique for patients undergoing tumour resection surgery on the basis that it might alter the risk of recurrence or metastasis.


Assuntos
Analgesia/métodos , Anestesia/métodos , Neoplasias/cirurgia , Avaliação de Resultados da Assistência ao Paciente , Assistência Perioperatória/métodos , Humanos
4.
Pediatr Res ; 75(2): 343-51, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24216543

RESUMO

BACKGROUND: To evaluate the effects of an amino acid-based formula (AAF) with synbiotics on growth and tolerance in healthy infants. The hypoallergenicity of this AAF with synbiotics was evaluated in subjects with cow's milk allergy (CMA). METHODS: Study 1: 115 full-term, healthy infants randomly received an AAF with synbiotics or a commercially available AAF for 16 wk. Subjects' weight, length, and head circumference were primary outcome measures. Stool characteristics and gastrointestinal (GI) symptoms were secondary outcome measures. Clinical examinations, dietary intake, clinical laboratory results, and adverse events were recorded. Study 2: hypoallergenicity of the AAF with synbiotics was evaluated in 30 infants and children with immunoglobulin E (IgE)-mediated CMA using a double-blind, placebo-controlled food challenge, and a 7-d feeding period. RESULTS: Study 1: comparable results in growth parameters and tolerance were observed for both groups. Minimal differences were observed in stool characteristics and GI symptoms throughout the study. Study 2: all 30 subjects with IgE-mediated CMA completed the study with no allergic reactions detected to challenges. CONCLUSION: These studies demonstrate that an AAF with synbiotics is safe and well tolerated and promotes normal growth when fed to healthy full-term infants as the sole source of nutrition and is hypoallergenic in subjects with CMA.


Assuntos
Aminoácidos/química , Fórmulas Infantis/química , Hipersensibilidade a Leite/imunologia , Simbióticos , Alérgenos , Animais , Bifidobacterium/metabolismo , Bovinos , Método Duplo-Cego , Feminino , Humanos , Tolerância Imunológica , Imunoglobulina E/química , Lactente , Fórmulas Infantis/administração & dosagem , Masculino , Oligossacarídeos/química , Probióticos/química
5.
J Neurosurg Case Lessons ; 8(3)2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-39008908

RESUMO

BACKGROUND: Cervical epidural hematomas are rare and can arise for many reasons. Patients typically present with pain and/or symptoms of spinal cord compression. Prompt surgical decompression is typically pursued when deficits are present in an effort to improve long-term neurological outcomes. However, the authors report the case of a patient with a traumatic dorsal cervical epidural hematoma with spontaneous resolution within 16 hours. OBSERVATIONS: A 49-year-old male with a history of C5-6 anterior cervical fusion 3 years prior presented with neck pain after blunt force trauma. The exam revealed only tenderness in the cervical spine. Initial computed tomography revealed fractures of C1 and C4. Urgent magnetic resonance imaging (MRI) demonstrated a dorsal cervical epidural hematoma causing compression of the spinal cord from the occiput to C5. An operation was scheduled for the following morning; however, after he reported new symptoms, repeat MRI was performed, which confirmed no evidence of a cervical epidural hematoma. LESSONS: This case demonstrates that a traumatic cervical epidural hematoma can resolve spontaneously within a short time frame. Close monitoring of these patients is vital, and it is important to reimage patients if new signs and/or symptoms arise to potentially change the timing and/or nature of the proposed surgery. https://thejns.org/doi/10.3171/CASE24167.

6.
J Neurol Surg B Skull Base ; 85(4): 406-411, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38966295

RESUMO

Objective While the transcondylar approach is technically challenging, it provides generous ventral and caudal exposure to the craniovertebral junction. This approach requires navigation around multiple eloquent neurovascular structures including the lower cranial nerves, vertebral artery and its branches, and the brainstem. Superficial exposure, including incision location and muscle dissection, can dramatically affect the surgical angle and maneuverability at depth. Methods We demonstrate the transcondylar approach in a step-by-step fashion in a formalin-embalmed, latex-injected cadaver head. Dissection within each layer of the suboccipital muscles was performed. A small cohort with an illustrative case is also included herein. Results The sternocleidomastoid (SCM) muscle was retracted anteriorly; the splenium capitis, semispinalis capitis, and longissimus capitis muscles were disconnected from the superior nuchal line and reflected inferomedially. The suboccipital muscle group was fully exposed. The superior and inferior oblique muscles were disconnected from the transverse process of C1. The superior oblique and the rectus capitis posterior major muscles were then dissected off the inferior nuchal line, and the suboccipital muscle group was retracted inferomedially en bloc . The greater auricular nerve was retracted laterally with the SCM, and the greater occipital nerve was retracted inferomedially with the suboccipital muscle group. Conclusion This technique avoids the obstructive muscle bulk that results from a myocutaneous approach while maximizing deep exposure. Understanding the detailed muscular anatomical relationship with the insertion location and suboccipital nerves is key to complete and safe extracranial dissection. Diligent dissection helps minimize postoperative pain and muscle spasm while optimizing the closure technique.

7.
Arthritis Rheumatol ; 76(6): 928-935, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38225923

RESUMO

OBJECTIVE: While thrombosis and pregnancy loss are the best-known clinical features of antiphospholipid syndrome (APS), many patients also exhibit "extra-criteria" manifestations, such as thrombocytopenia. The mechanisms that drive APS thrombocytopenia are not completely understood, and no clinical biomarkers are available for predicting antiphospholipid antibody (aPL)-mediated thrombocytopenia. Calprotectin is a heterodimer of S100A8 and S100A9 that is abundant in the neutrophil cytoplasm and released upon proinflammatory neutrophil activation. Here, we sought to evaluate the presence, clinical associations, and potential mechanistic roles of circulating calprotectin in a cohort of primary APS and aPL-positive patients. METHODS: Levels of circulating calprotectin were determined in plasma by the QUANTA Flash chemiluminescent assay. A viability dye-based platelet assay was used to assess the potential impact of calprotectin on aPL-mediated thrombocytopenia. RESULTS: Circulating calprotectin was measured in 112 patients with primary APS and 30 aPL-positive (without APS criteria manifestations or lupus) patients as compared to patients with lupus (without APS), patients with unprovoked venous thrombosis (without aPL), and healthy controls. Levels of calprotectin were higher in patients with primary APS and aPL-positive patients compared to healthy controls. After adjustment for age and sex, calprotectin level correlated positively with absolute neutrophil count (r = 0.41, P < 0.001), positively with C-reactive protein level (r = 0.34, P = 0.002), and negatively with platelet count (r = -0.24, P = 0.004). Mechanistically, we found that calprotectin provoked aPL-mediated thrombocytopenia by engaging platelet surface toll-like receptor 4 and activating the NLRP3-inflammasome, thereby reducing platelet viability in a caspase-1-dependent manner. CONCLUSION: These data suggest that calprotectin has the potential to be a functional biomarker and a new therapeutic target for APS thrombocytopenia.


Assuntos
Síndrome Antifosfolipídica , Plaquetas , Complexo Antígeno L1 Leucocitário , Trombocitopenia , Humanos , Síndrome Antifosfolipídica/sangue , Feminino , Complexo Antígeno L1 Leucocitário/sangue , Masculino , Pessoa de Meia-Idade , Adulto , Trombocitopenia/sangue , Plaquetas/metabolismo , Biomarcadores/sangue , Receptor 4 Toll-Like/sangue , Anticorpos Antifosfolipídeos/sangue
8.
J Neurosurg Case Lessons ; 6(13)2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37773761

RESUMO

BACKGROUND: Bilateral cerebellopontine angle (CPA) lipomas are extremely rare. Herein the authors present a case of bilateral CPA lipomas in an infant along with a literature review of bilateral CPA lipomas. OBSERVATIONS: A newborn girl was incidentally found to have bilateral CPA lipomas during the workup for an occipital encephalocele. The encephalocele was repaired primarily on day 2 after birth. The patient demonstrated no symptoms associated with the bilateral CPA lipomas. Eight cases of bilateral CPA lipomas were identified in the literature review and are summarized. Conservative management is the consensus strategy, given minimum growth of the tumor and the high risk of surgical intervention. LESSONS: This is the first reported case of bilateral CPA lipomas in an infant as well as the first with a coexisting intracranial malformation. Intracranial lipomas share an extremely low growth rate and typically do not cause severe symptoms. The management of asymptomatic or mildly symptomatic bilateral CPA lipomas is usually conservative.

9.
J Neurosurg Pediatr ; 32(5): 545-552, 2023 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728396

RESUMO

Stereoelectroencephalography (sEEG) was pioneered in France, at a time when cerebral anatomy was invisible to contemporaneous imaging modalities. Epilepsy surgeons relied on indirect targeting techniques to identify epileptogenic tissue. Since then, alongside the rapid rise of medical imaging technology, sEEG has experienced dramatic stepwise progress. A flurry of advancements has pushed this technique to its current-day standards, enabling neurosurgeons to access any intracranial location in a safe, highly precise, and expeditious manner. Presently, epilepsy surgeons throughout the world apply robot-assisted sEEG. Herein, the authors chronicle this incredible evolution.


Assuntos
Epilepsia Resistente a Medicamentos , Epilepsia , Humanos , Eletroencefalografia/métodos , Técnicas Estereotáxicas , Epilepsia/diagnóstico por imagem , Epilepsia/cirurgia , Mapeamento Encefálico/métodos , Radiografia , Eletrodos Implantados , Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/cirurgia , Estudos Retrospectivos
10.
Neurosurg Clin N Am ; 34(3): 381-391, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37210127

RESUMO

Meningiomas are the most common intracranial extra-axial primary tumor. Although most are low grade and slow growing, resection can be technically challenging, particularly when located at the skull base. Appropriate craniotomy and approach selection are of paramount importance to minimize brain retraction, optimize exposure, and achieve complete resection. This article summarizes various craniotomies and their approaches to meningiomas, and illustrates some nuances in performing these techniques with cadaveric dissection and operative videos.


Assuntos
Neoplasias Meníngeas , Meningioma , Neoplasias da Base do Crânio , Humanos , Meningioma/cirurgia , Neoplasias Meníngeas/cirurgia , Procedimentos Neurocirúrgicos/métodos , Base do Crânio/cirurgia , Craniotomia/métodos , Neoplasias da Base do Crânio/patologia
11.
Front Oncol ; 13: 1126550, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36937440

RESUMO

Introduction: Meningiomas are the most common primary central nervous system (CNS) tumors in adults, representing approximately one-third of all primary adult CNS tumors. Although several recent publications have proposed alternative grading systems of meningiomas that incorporate genomic and/or epigenomic data to better predict meningioma recurrence and progression-free survival, our understanding of driving forces of meningioma development is still limited. Objective: To define gene expression signatures of the most common subtypes of meningiomas to better understand cellular processes and signaling pathways specific for each tumor genotype. Methods: We used RNA sequencing (RNA-seq) to determine whole transcriptome profiles of twenty meningiomas with genomic alterations including NF2 inactivation, loss of chr1p, and missense mutations in TRAF7, AKT1 and KLF4. Results: The analysis revealed that meningiomas with NF2 gene inactivation expressed higher levels of BCL2 and GLI1 compared with tumors harboring TRAF7 missense mutations. Moreover, NF2 meningiomas were subdivided into two distinct groups based on additional loss of chr1p. NF2 tumors with intact chr1p were characterized by the high expression of tumor suppressor PTCH2 compared to NF2 tumors with chr1p loss. Taken together with the high expression of BCL2 and GLI1, these results suggest that activation of Sonic Hedgehog pathway may contribute to NF2 meningioma development. In contrast, NF2 tumors with chr1p loss expressed high levels of transcription factor FOXD3 and its antisense RNA FOXD3-AS1. Examination of TRAF7 tumors demonstrated that TRAF7 regulates a number of biomechanically responsive genes (KRT6a, KRT16, IL1RL1, and AQP3 among others). Interestingly, AKT1 and KLF4 meningiomas expressed genes specific for PI3K/AKT signaling pathway, suggesting overlapping gene signatures between the two subtypes. In addition, KLF4 meningiomas had high expression of carcinoembryonic antigen family members CEACAM6 and CEACAM5. Conclusions: Each group of meningiomas displayed a unique gene expression signature suggesting signaling pathways potentially implicated in tumorigenesis. These findings will improve our understanding of meningioma tumorigenesis and prognosis.

12.
Children (Basel) ; 9(11)2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36360408

RESUMO

In situ stabilization is a widely accepted treatment for slipped capital femoral epiphysis (SCFE) despite risks of avascular necrosis (AVN) and femoroacetabular impingement (FAI). The modified Dunn procedure with surgical hip dislocation attempts to maintain epiphyseal perfusion and allows anatomic epiphyseal repositioning, theoretically reducing AVN and FAI risks. We systematically evaluated the literature, elucidating overall and stability-stratified rates of AVN following the modified Dunn procedure, and revision rates in non-AVN patients. Using Ovid and MEDLINE (PubMed), studies involving the modified Dunn procedure were evaluated for age, stability, preoperative slip (Southwick) angle, ROM at follow-up, outcome metrics, and revisions. Utilizing a random effect model of proportions, we determined overall and stability-stratified AVN rates, and revision rates in patients without AVN.673 patients (688 SCFEs) who underwent modified Dunn procedure were included. Overall AVN rate was 14.3% with a 95% Confidence Interval (CI) of 9.3 to 20.2%. AVN rate in stable slips was 10.9% (95% CI: 6.0 to 17.1%) and 19.9% (95% CI: 12.8% to 28.1%) in unstable slips. Revision rate in non-AVN patients was 13.3% (95% CI: 8.3% to 19.2%). Fixation failures occurred following K-wire or small-caliber (<6.5 mm) screw fixation. Overall mean Harris Hip Score (HHS) was excellent (>90 points). Mean HHS was 98.9 points (range of means: 86 to 99 points) in stable cases, and 90.5 points (range of means: 73 to 98 points) in unstable cases. Patients undergoing modified Dunn procedure had excellent clinical outcomes and low incidences of AVN. Further studies are needed to determine if modified Dunn osteotomy with surgical hip dislocation is a viable alternative to in situ pinning for treatment of severe SCFE.

13.
Diagnostics (Basel) ; 12(6)2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35741134

RESUMO

BACKGROUND: New tools for the assessment and prediction of the severity of hospitalized COVID-19 patients can help direct limited resources to patients with the greatest need. Circulating levels of calprotectin (S100A8/S100A9) reflect inflammatory activity in multiple conditions, and have been described as being elevated in COVID-19 patients, but their measurement is not routinely utilized. The aim of our study was to assess the practical and predictive value of measuring circulating calprotectin levels in patients at admission and during their hospitalization. METHODS: Circulating calprotectin levels were measured in 157 hospitalized patients with COVID-19 using an automated quantitative chemiluminescent assay. RESULTS: Circulating calprotectin levels were strongly correlated with changing respiratory supplementation needs of patients. The overall trajectory of circulating calprotectin levels generally correlated with patient improvement or deterioration. CONCLUSIONS: Routine measurement of circulating calprotectin levels may offer a valuable tool to assess and monitor hospitalized patients with COVID-19, as well as other acute inflammatory conditions.

14.
JCI Insight ; 6(15)2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34166229

RESUMO

The release of neutrophil extracellular traps (NETs) by hyperactive neutrophils is recognized to play an important role in the thromboinflammatory milieu inherent to severe presentations of COVID-19. At the same time, a variety of functional autoantibodies have been observed in individuals with severe COVID-19, where they likely contribute to immunopathology. Here, we aimed to determine the extent to which autoantibodies might target NETs in COVID-19 and, if detected, to elucidate their potential functions and clinical associations. We measured anti-NET antibodies in 328 individuals hospitalized with COVID-19 alongside 48 healthy controls. We found high anti-NET activity in the IgG and IgM fractions of 27% and 60% of patients, respectively. There was a strong correlation between anti-NET IgG and anti-NET IgM. Both anti-NET IgG and anti-NET IgM tracked with high levels of circulating NETs, impaired oxygenation efficiency, and high circulating D-dimer. Furthermore, patients who required mechanical ventilation had a greater burden of anti-NET antibodies than did those not requiring oxygen supplementation. Levels of anti-NET IgG (and, to a lesser extent, anti-NET IgM) demonstrated an inverse correlation with the efficiency of NET degradation by COVID-19 sera. Furthermore, purified IgG from COVID-19 sera with high levels of anti-NET antibodies impaired the ability of healthy control serum to degrade NETs. In summary, many individuals hospitalized with COVID-19 have anti-NET antibodies, which likely impair NET clearance and may potentiate SARS-CoV-2-mediated thromboinflammation.


Assuntos
Autoanticorpos/imunologia , COVID-19/imunologia , Armadilhas Extracelulares/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Autoanticorpos/sangue , COVID-19/sangue , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Masculino , Pessoa de Meia-Idade , Neutrófilos/imunologia , Adulto Jovem
15.
BJA Educ ; 24(5): 147-154, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38646451
16.
J Am Coll Radiol ; 16(8): 1108-1113, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30956087

RESUMO

PURPOSE: Readability of patient education materials has been linked to health outcomes, and reports on patient education materials in radiology have demonstrated readability levels higher than recommended. Few studies in radiology, however, have assessed patient comprehension of Spanish-language health care educational materials. The purpose of this study was thus to assess the readability of patient education materials written in Spanish from RadiologyInfo.org. METHODS: All patient education materials written in Spanish available in July 2017 from the RadiologyInfo.org patient education library were compiled into a database over a 1-day period. After modification and editing to minimize artificial changes in readability levels, four readability scales were used to assess the texts: the Gilliam-Peña-Mountain scale, the Läsbarhets formula, the rate index formula, and the SOL formula. Readability was compared among scales using analysis of variance, and inter- and intrarater variability was assessed using intraclass correlation coefficients. RESULTS: In total, 134 patient education articles written in Spanish were included from the RadiologyInfo.org patient education library. The mean readability grade level was the 10th grade reading level or higher for all scales (average, 12th grade); only one article was written below the 8th grade level. There was no significant difference in readability level on the basis of readability scale used. CONCLUSIONS: Spanish-language patient educational materials provided at the RadiologyInfo.org website are written at levels too high for the average patient. Future efforts should be made to improve the readability of these patient education materials for English and Spanish speakers alike.


Assuntos
Letramento em Saúde , Hispânico ou Latino , Internet , Educação de Pacientes como Assunto , Radiologia/educação , Leitura , Compreensão , Humanos , Idioma
17.
World J Nucl Med ; 17(4): 223-227, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30505218

RESUMO

Our goal for this study was to evaluate the comprehensiveness of nuclear medicine (NM) residency websites from the USA and Canada. The authors searched all the existing NM residency programs as listed in the Fellowship and Residency Electronic Interactive Database and the Canadian Residency Matching Service. We analyzed each website for the presence or absence of 44 elements previously identified as important considerations for medical students applying to residency. We compared criteria prevalence between regions and program size using t-tests and analysis of variance. Our results showed that, of 47 NM residencies, 9 did not have a dedicated website, leaving a total of 38 websites available for evaluation. The individual websites in the USA had a mean of 15 of 44 elements sought; in contrast, Canadian programs had 26 of 44 elements sought. The most common elements included contact e-mail, mailing address, and comprehensive faculty listings. Information about resident hometown, academic interests, and extracurricular interests was only included in 3% of the websites. Only 3% of websites included case description and 11% included rotation schedule. Courses attended were included in 5%, educational resources in 8%, and resident education was included in 5% of the websites. In conclusion, about one in five NM residency programs do not have a publicly available website. The websites that do exist are incomprehensive, containing an average of only 32% of elements sought for the USA programs and 41% of elements sought in Canadian programs. Residency program websites are an important tool in recruiting medical students. Addressing the lack of available websites as well as the gap in content of the websites that does exist may improve recruitment of students to NM residency programs.

18.
Biochim Biophys Acta ; 1526(2): 141-6, 2001 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-11325535

RESUMO

Within articular cartilage, the chondron microenvironment will influence chondrocyte behaviour and response to loading. Chondrons were extracted from intact cartilage using either mechanical homogenisation (MC) or enzymatic digestion (EC) and cell and matrix morphology in unstrained and compressed agarose constructs was examined. Isolated chondrocytes (IC) were used for comparison. Immunolocalisation of type VI collagen and keratan sulphate revealed differences in the structure of the pericellular microenvironment such that MC most closely resembled chondrons in situ. The unstrained cell diameters of IC and EC were larger than MC at day 1 and increased significantly over a 7 day culture period. In contrast, cell diameters for MC remained constant. Compression of constructs at day 1 resulted in cell deformation for IC and EC but not MC. The two chondron extraction methods yielded chondrons of differing matrix morphology and associated differences in cell size and cellular response to load. The results indicate that the pericellular microenvironment of MC initially possessed a greater mechanical integrity than that of EC. Although these differences may be reduced with time in culture, characterisation of mechanically isolated chondrons suggests that the stiffness of the chondrons in situ may be greater than previous estimates.


Assuntos
Cartilagem Articular/citologia , Condrócitos/citologia , Animais , Separação Celular/métodos , Tamanho Celular , Condrócitos/ultraestrutura , Colágeno/análise , Cães , Matriz Extracelular/ultraestrutura , Imuno-Histoquímica , Sulfato de Queratano/análise , Microscopia Confocal , Sefarose
19.
J Bone Miner Res ; 10(4): 558-67, 1995 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7610926

RESUMO

This cross-sectional twin study aimed to quantify the roles of constitutional and lifestyle factors on bone mass in adolescent and young adult women. Areal bone density (BMD) at the lumbar spine, femoral neck, Ward's triangle, and total hip, total body bone mineral content (BMC), and lean mass and fat mass were measured using dual energy X-ray absorptiometry (DXA) in 215 female volunteer twin pairs (122 monozygotic [MZ], 93 dizygotic [DZ]) aged 10 to 26 years. Height, weight, menarchial history, dietary calcium intake, physical activity, current tobacco use, and alcohol consumption were determined by questionnaire. Mean BMD increased with age to around 16 years, when it reached a plateau. Within-pair differences in BMD at the lumbar spine (expressed as a percentage of the pair mean BMD) were univariately associated with pair differences in menarchial status (14 +/- 3%), height (0.7 +/- 0.1% per cm), weight (0.4 +/- 0.1% per kg), lean mass (1.0 +/- 0.1% per kg), and fat mass (0.5 +/- 0.1% per kg). Only menarchial status, height, and lean mass, however, were independent predictors. At the proximal femoral sites, within-pair BMD differences were associated with within-pair lean mass differences (1.0 to 1.1 +/- 0.2%/kg), and no other factor was significant. The same conclusions applied to within-pair differences in BMD/height. Total body BMC was independently associated with menarchial status, height, lean mass, and fat mass; the effects of the latter two variables were stronger in pairs both premenarchial. After adjusting for constitutional factors, no lifestyle factor was independently predictive. By reducing collinearity, the cotwin method clearly identified that lean mass, not fat mass, was the major independent determinant of bone mass at the hip, both pre- and postmenarche.


Assuntos
Composição Corporal/fisiologia , Densidade Óssea/fisiologia , Fêmur/fisiologia , Estilo de Vida , Vértebras Lombares/fisiologia , Absorciometria de Fóton , Adolescente , Adulto , Consumo de Bebidas Alcoólicas , Análise de Variância , Estatura/fisiologia , Cálcio da Dieta/administração & dosagem , Criança , Estudos Transversais , Exercício Físico , Feminino , Humanos , Menarca , Análise de Regressão , Fumar , Inquéritos e Questionários
20.
J Neuropathol Exp Neurol ; 43(4): 376-83, 1984 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-6429287

RESUMO

Cortical astrocytes of normal mammalian brain are endowed with a high affinity uptake system for beta-Alanine which is competitively inhibited by gamma aminobutyric acid (GABA), a neurotransmitter strongly implicated in epileptogenesis. We evaluated (3H) beta-Alanine uptake by reactive astrocytes proliferating within scar of epileptogenic foci induced in rat motor cortex by microinjections of 100 mM ferric chloride. Following in vitro incubation of scar tissue with (3H) beta-Alanine, ultrastructural morphometry of grain patterns at 5, 30 and 120 days post injection revealed early and significant grain count increases (p less than 0.001) over astroglial processes, predominantly those related to perivascular glial end-feet. Astrocytic cell body and endothelial cell counts showed a more gradual and stepwise increase. Similar data were obtained by comparing visual and edited mean astrocytic grain counts. These results suggest that the enhanced uptake of reactive astrocytes may reflect a marked decrease of inhibitory GABAergic neurons within ferric chloride-induced scars.


Assuntos
Alanina/metabolismo , Córtex Cerebral/patologia , Epilepsia/patologia , beta-Alanina/metabolismo , Animais , Astrócitos/patologia , Córtex Cerebral/metabolismo , Cloretos , Epilepsia/induzido quimicamente , Epilepsia/metabolismo , Compostos Férricos , Masculino , Ratos , Ratos Endogâmicos , beta-Alanina/antagonistas & inibidores , Ácido gama-Aminobutírico/farmacologia
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