Heritable dentin defects have been divided into 2 main categories: dentinogenesis imperfecta (DI) and dentin dysplasia (DD). Recent studies have shown that they share many features in common. Of the connective tissue diseases, only osteogenesis imperfecta (OI) has been linked to these disorders. So far, no definitive relation between the type of OI and the dental involvement can be established. Familial occurrence of DI with OI cannot be comprehensively explained by mutations in type I collagen genes. No information about the gene defects in DD is available. At the ultrastructural level, the organization of the normally cross-striated collagen fibers in the dentin matrix varies markedly in patients affected by DI. 相似文献
Summary The studies were carried out on male Wistar rats subjected to running within an electric rotating drum. The animals were divided into four experimental groups, differing one from another as to the duration of training. Each training session lasted 30 days. In the first group the daily run lasted 3 min, in the second group 5 min; in the third group, a 1 min run on the first day, and one min longer on each successive day; in the fourth group a 2 min run on the first day and for two min longer on each successive day.The determinations made prior to and after training included the peripheral blood erythrocyte (Er) and reticulocyte (Ret.) count, the hemoglobin concentration (Hb) and packed cell volume (PCV) and, determined by spectrophotometric methods, the activity of pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G6PD) and glutathione reductase (GR). Training induced an improvement of all enzymatic activities. The heavier the physical exertion, the more intensive was the enzymatic activity of red blood cells, due to the intensification of bone marrow erythropoetic activity under physical exertion and the appearance of young red cells in peripheral blood. All the experimental groups revealed a drop in erythrocyte count (Er), hemoglobin concentration (Hb), and hematocrit values (PCV), as well as an increase in the reticulocytes count (Ret) and in the activity of all the enzymes investigated. In the fourth group anemia was detected: prolonged endurance training decreased the RBC by 24.2%, Hb by 31.1%, PCV by 26.2% and increased the reticulocyte count by 881.6%. Pronounced loading with physical effort leads to shifts in the glucose utilization ratio along particular erythrocyte metabolic pathways. This change in enzymatic activities may prove to be one of the causes of faster elimination of old RBCs. 相似文献
Constitutional mutations in the RB1 gene predispose to retinoblastoma development. Hence genetic screening of retinoblastoma patients and relatives is important for genetic counseling purposes. In addition, RB1 gene mutation studies may help decipher the molecular mechanisms leading to tumors with different degrees of penetrance or expressivity. In the course of genetically screening of 107 hereditary and non-hereditary retinoblastoma patients (11 familiar bilateral, 4 familiar unilateral, 49 sporadic bilateral and 43 sporadic unilateral) and kindred from Spain, Colombia and Cuba, using direct PCR sequencing, we observed 45 distinct mutations and four RB1 deletions in 53 patients (9 familiar bilateral, 2 familiar unilateral, 31 sporadic bilateral and 11 sporadic unilateral). Most of these mutations (26/45, 57%) have not been reported before. In 32 patients, the predisposing mutations correspond to nonsense (mainly CpG transitions) and small insertions or deletions whose expected outcome is a truncated Rb protein that lacks the functional pockets and tail. Five single aminoacid replacements and seventeen mutations affecting splicing sites were also observed in retinoblastoma patients. Two of these sixteen mutations are of unclear pathogenic nature. 相似文献
Loxoscelism, the term used to describe envenomation with brown spiders, is characterized by a dermonecrotic lesion at the bite site. In the present investigation we submitted albino rabbits to an acute experimental envenomation protocol using Loxosceles intermedia (brown spider) venom, with in order to determine the pathogenesic features of the lesion induced by this spider, which is the cause of several accidents throughout the world. Rabbits received intradermal injections of the venom and were monitored over the first 4 h, and then at 12 h and 1, 2 and 5 days after envenomation. Histological specimens from 3 rabbits per time point were collected from euthanized animals and processed for histological examination by light microscopy. Major findings observed during the first 4 h were oedema, haemorrhage, degeneration of blood vessel walls, plasma exudation, thrombosis, neutrophil accumulation in and around blood vessels with an intensive diapedesis, a diffuse collection of inflammatory cells (polymorphonuclear leucocytes) in the dermis, and subcutaneous muscular oedema. Over the following hours and up to 5 days after envenomation the changes progressed to massive neutrophil infiltration (with no other leucocytes) into the dermis and even into subcutaneous muscle tissue, destruction of blood vessels, thrombosis, haemorrhage, myonecrosis, and coagulative necrosis on the 5th day. 相似文献
Introduction: Neuropsychiatric systemic lupus erythematosus (NPSLE) is characterized by a heterogeneity of clinical manifestations. The absence of diagnostic criteria and the lack of clinical trials is a challenge in clinical practice.
Areas covered: A literature review was performed to describe epidemiology, characterization (clinical, immunological, and imaging), diagnosis and treatment of NPSLE. Classification criteria have been the first step towards a uniform definition. More recently, different attribution models have been developed to help to determine if the NP event is due to SLE. Disease activity is a major risk factor for NP events. Cytokines and autoantibodies are associated with NP events, however, only a few studies have identified risk factors for individual NP events.
Expert opinion: Further research needs to search for and validate biomarkers for NPSLE and individual NP events, including neuroimaging findings, attribution models, and serologic markers. This will be a fundamental step in planning randomized control trials in the treatment of NPSLE to improve outcome. 相似文献
Adolescence is a critical period in the consolidation of healthy lifestyles that can last into adulthood. To analyze changes in food consumption and eating behaviors in high-school adolescents during the first confinement, a cross-sectional study was conducted at the end of confinement in Spain. Changes in the frequency or quantity of consumption of different types of food and food-related behaviors were analyzed. Socioeconomic and health-related variables were also considered. To determine whether dietary changes were related to socioeconomic position (SEP), Poisson regression models with robust variance were estimated. Overall, there were some changes towards a healthier diet such as an increase in fruit consumption (38.9%) and a decrease in the consumption of soft drinks (49.8%), sweets and pastries (39.3%), and convenience foods (49.2%). Some changes, however, were related to less healthy behaviors, such as a more irregular pattern of meal distribution (39.9%) or an increase in snacking between meals (56.4%). Changes towards less healthy eating were also related to students’ SEP. The risk of worsening the diet was found to be 21% higher in adolescents from a more disadvantaged SEP. Future public policies could be adapted to avoid increasing nutritional and health inequalities. 相似文献
The coronavirus disease (COVID-19) pandemic might affect tuberculosis (TB) diagnosis and patient care. We analyzed a citywide electronic TB register in Blantyre, Malawi and interviewed TB officers. Malawi did not have an official COVID-19 lockdown but closed schools and borders on March 23, 2020. In an interrupted time series analysis, we noted an immediate 35.9% reduction in TB notifications in April 2020; notifications recovered to near prepandemic numbers by December 2020. However, 333 fewer cumulative TB notifications were received than anticipated. Women and girls were affected more (30.7% fewer cases) than men and boys (20.9% fewer cases). Fear of COVID-19 infection, temporary facility closures, inadequate personal protective equipment, and COVID-19 stigma because of similar symptoms to TB were mentioned as reasons for fewer people being diagnosed with TB. Public health measures could benefit control of both TB and COVID-19, but only if TB diagnostic services remain accessible and are considered safe to attend. 相似文献
Neurosurgical Review - A preferred treatment for residual/recurrent pituitary adenomas has not been established. The existence of higher complication rates for revision surgeries remains under... 相似文献