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1.
BACKGROUND: The pathogenesis of steroid-induced osteonecrosis of the femoral head remains unclear. Femoral head reconstruction after collapse is related to the bone remodeling due to disorder of the bone formation-absorption coupling. “Removing Blood Stasis” Method has been shown to have a positive effect on the disease in clinics. However, the mechanisms by which the “Removing Blood Stasis” Method confers bone repair after osteonecrosis remain poorly understood. OBJECTIVE: To explore the effect of “Removing Blood Stasis” Method on bone repair in rabbits with steroid-induced femoral head osteonecrosis. METHODS: Fifty New Zealand rabbits were randomly assigned into three groups: normal control (n=10), model (n=20) and Taohong Siwu Decoction (n=20) groups, respectively. The steroid-induced osteonecrosis of the femoral head animal models were established by intramuscular injection of endotoxin combined with methylprednisolone (MPS). Rabbits in Taohong Siwu Decoction group were intragastrically administered with 0.3 g/kg of Taohong Siwu Decoction suspension after the last injection of methylprednisolone. The control and model groups were administrated by equal volume of ultrapure water for 8 consecutive weeks. High-resolution MRI and pathological determinations were used to assess the successful models. Protein expression levels of ABCB1, RUNX2, OPN, RANK, RANKL, PPAR, osteoprotegerin (OPG), vascular endothelial growth factor (VEGF) in rabbit femoral heads were detected by western blot assay. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining showed that trabecular bone fracture, karyopyknosis, empty lacunae, necrotic bone marrow cells were seen in the model group. Empty lacunae rate in the model group was significantly different from that in the normal control group (P < 0.05). Bone formation was active and kept better trabecular morphology in the Taohong Siwu Decoction group. It suggested that “Removing Blood Stasis” Method can improve repair of necrotic area. (2) In the model group, femoral head with a wide range of low-density areas in high-resolution MRI; Taohong Siwu Decoction group showed the relatively normal shape of the femoral head with small areas of low density. It suggested that “Removing Blood Stasis” Method can improve image changes in the necrotic area. (3) Protein expression levels of RUNX2, RANK, RANKL were significantly up-regulated but protein expression levels of ABCB1, OPG, VEGF were significantly down-regulated in the model group compared with the normal control group; whereas, they were all significantly up-regulated in the Taohong Siwu Decoction group compared with the model group, except for RANK and RANKL (P < 0.05). These results suggest that the “Removing Blood Stasis” Method can promote bone repair in steroid-induced femoral head osteonecrosis rabbits by regulating protein expressions of ABCB1, RUNX2, RANK, RANKL, OPG, and VEGF. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

2.
Objective To investigate the effect of CCAAT enhancer binding protein α(C/EBPα) on differentiation and apoptosis in the acute myeloid leukemia HL60 cells in vitro and in vivo and its possible mechanism. Methods The C/EBPα expression plasmid pEGFP-C/EBPα and empty control plasmid were respectively transfected into HL60 cells with cationic liposome as transfected group and empty plasmid transfected group, and untreated HL60 cells served as control group. The cells stably expressing the C/EBPα gene were obtained by G418 selection. The morphological changes were observed under light microscope following WrightGiemsa staining. MTT assay was employed to evaluate cell proliferation, and flow cytometry(FCM) was performed to analyze cell apoptosis. Meanwhile, the expression of c-myc was respectively detected by RT-PCR and Western blot both at the mRNA and protein level. Twenty BALB/c nude mice were divided into 3 groups in a completely randomized design: 7 mice in transfected group, 7 mice in empty plasmid transfected group and 6 in control group. Three kinds of cells including pEGFP-C/EBPα-HL60 cells, pEGFP -HL60 cells and the control HL60 cells were injected into mice separately through the subcutaneous. The mice were sacrificed at 20 d after injection. The mass and size of subcutaneous xenograft tumors were measured and the cell apoptosis of subcutaneous tumor were detected by TUNEL. Results The pEGFP-C/EBPα-HL60 cell line stably expressing the C/EBPα gene was screened out. Compared to either empty plasmid transfected group or control group, the expression of C/EBPα could promote cellular differentiation of HL60. FCM showed higher apoptotic rate in transfected group[ (21.9±4.5)%,P<0.05 ] ,while (5.4±1.4)% in control group and (5.0±1.3)% in empty plasmid transfected group. c-myc expression was significantly down-regulated by C/EBPα both at the mRNA and protein level. The mass and size of tumors in transfected group were smaller than those in empty plasmid transfected group and control group [ (5.35±1.12)g and(25±4)mm in control group, (5.12±1.31)g and ( 18±3)mm in empty plasmid transfected group ,while (3.26±0.72)g and ( 11±2)mm in transfected group, all P<0.05]. More apoptosis cells were found in subcutaneous tumor of transfected group(both P<0.05). Conclusion C/EBPα can not only inhibit the proliferation, but also induce massive apoptosis of HL60 cells, meanwhile C/EBPα is a tumor suppressor of acute myeloid leukemia.  相似文献   

3.
BACKGROUND: The incidence of femoral head necrosis after internal fixation in femoral neck fracture is at high level, but the risk factors are still under discussion. OBJECTIVE:To retrospectively propose and analyze the relative risk factors of femoral head necrosis after internal fixation with femoral neck fracture in patients younger than 60 years old. METHODS:Data from 199 patients with femoral neck fractures, younger than 60 years, undergoing closed reduction and internal fixation were analyzed retrospectively. Seven factors including age, sex, body mass index, Garden classification, fracture seasons, reduction quality and weight-bearing time after internal fixation were statistically analyzed to evaluate their correlation with femoral head necrosis. RESULTS AND CONCLUSION: The incidence of femoral head necrosis was 13.1% among the 199 cases. Body mass index, Garden classification, fracture seasons, reduction quality were significantly associated with femoral head necrosis. The age, sex and weight-bearing time were in significantly associated with femoral head necrosis. In multivariate logistic regression analysis, Garden classification, reduction quality and fracture seasons (winter versus summer) had overt effects on development of femoral head necrosis. These results suggest that Garden classification and reduction quality make an important effect on the healing of femoral neck fracture. In addition, fracture in winter may be the risk factor of the femoral head necrosis after internal fixation in femoral neck fracture.| 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

4.
5.
BACKGROUND: Extracorporeal shock wave has been shown to influence the physiological function of endothelial cells via the activation of mechanoreceptors and specific signal transduction system, and gene expression regulation. OBJECTIVE:To explore the impact of different energy flow densities and numbers of shots of extracorporeal shock waves on the new vessel formation ability, migration capability and apoptosis of bone microvascular endothelial cells. METHODS: Bone microvascular endothelial cells isolated from the femoral head of patients undergoing arthroplasty were subcultured in vitro, and then were immunofluorescently evaluated with endothelial cell marker antibodies to CD31 and von Willebrand factor (vWF), and grouped according to different energy flow densities (low, 0.03 mJ/mm2; high, 0.11 mJ/mm2) and numbers of shots (400 and 800). Capillary-like tube formation, migration capability and apoptosis of bone microvascular endothelial cells were determined by 3-D culture in vitro, scratch test, and flow cytometry, respectively. RESULTS AND CONCLUSION: vWF and CD31 were positively expressed in approximately 100% of bone microvascular endothelial cells, which indicates the cultured cells had characterization of microvascular endothelial cells. Extracorporeal shock wave enhanced angiogenesis and migration capability of bone microvascular endothelial cells derived from the femoral head, and especially low-energy flow density of extracorporeal shock wave exerted more superior effects. Angiogenesis of bone microvascular endothelial cells was decreased with the increased shot number in the low-energy flow density group. In addition, extracorporeal shock wave inhibited bone microvascular endothelial cell apoptosis induced by steroids. Our results suggest that energy flow density and number of shots of extracorporeal shock waves impact the physiological function of bone microvascular endothelial cells derived from the femoral head. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

6.
BACKGROUND: Blood coagulation factor V gene mutation in non-traumatic femoral head necrosis has been shown to have an higher incidence than that in healthy and secondary non-traumatic femoral head necrosis, and the incidence of thrombosis is positively related. Inactivated blood coagulation factor V can accelerate the activation of prothrombin and the generation of thrombin. Mutations at arg-306, arg-506 and arg-679 will result in the blood clots and hypercoagulable state. Here, this study is designed to investigate the influence of R506Q/R679Q on osteonecrosis. OBJECTIVE: To establish the mouse model of mutations of Gln506Arg and Gln679Arg in coagulation Factor V (Factor VR506Q/R679Q). METHODS: Factor VR506Q/R679Q point mutation target vector was constructed by molecular cloning technology, the linearization vector was transfected into embryonic stem cells, and then G418-resistant cells were screened and used for microinjection. The target blastocysts were transplanted to the fallopian tube of estrus mice to obtain the Chimera mice carrying bilateral LoxP gene, followed by mated with CMV-cre transgenic mice, and then the mice with Factor VR506Q/R679Q point mutations were obtained. After genotype identification by PCR, hematoxylin-eosin staining results and percentage of empty lacunae were compared between the mutant and wild-type mice, and rat bone tissue and bone mass were analyzed. RESULTS AND CONCLUSION: There were no obvious abnormalities in the embryonic and postnatal development, percentage of empty lacunae and bone mass of Factor VR506Q/R679Q point mutation mice when compared with the wild-type mice. These results suggest that the mouse model with Factor VR506Q/R679Q point mutation is established successfully, but there is no significant change in the bone tissue. The following research should focus on the effect of external stimulus on the incidence of osteonecrosis in a mutant mouse. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

7.
BACKGROUND: The femoral neck system is a novel fixation device for unstable femoral neck fractures. OBJECTIVE: To compare and analyze the mechanical stability of three kinds of internal fixation in Pauwels III unstable femoral neck fractures by finite element method. METHODS: On the basis of the validated femoral finite element model (intact group), the model was cut to make a Pauwels III 70° unstable fracture of the femoral neck. Different internal fixation models were implanted to simulate clinical surgery. This study established femoral neck system fixation (model A), inverted triangular cannulated screw fixation (model B) and 4 diamond-shaped cannulated screw fixation (model C). All the nodes under the distal end of the femur were restrained for the three groups of models, and 700 N, 1 400 N and 2 100 N compressive loads were applied to the femoral head. Through calculation and analysis, the Von Mises stress distribution and deformation of each group of models were observed, and the mechanical stability of each group of models was compared. RESULTS AND CONCLUSION: (1) The maximum deformation of the three groups of models under various loads occurred in the femoral head. When compressed for 2 100 N, the deformation of model A was 2.06 mm less than that of intact group 2.17 mm, while the deformations of model B and model C were both higher than that of intact group, with the distributions of 2.39 mm and 2.33 mm. (2) Under various loads, the stress in model A group was also the smallest. Under 2 100 N, the stress peak in model A was 297.31 MPa, distributed at the joint position of anti-rotation screw and locking screw, while the stress peak in model B was 543.18 MPa, distributed at the fracture joint position of the third screw in the inverted triangle. However, the deformation and stress of model C were intermediate between model A and model B, and the maximum stress peak value was distributed at the bottom hollow of the cannulated screw fracture, reaching 315.61 MPa at 2 100 N. (3) The compressive stiffness and stress analysis of models of the three groups showed that model A < model C < model B. (4) It is concluded that the mechanical stability of femoral neck system for femoral neck fracture is better than that of three and four cannulated screws fixation, and it can effectively prevent femoral neck shortening. Femoral neck system is a recommended internal fixation method for unstable femoral neck fractures. © 2023, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.  相似文献   

8.
BACKGROUND: Current research has shown that tumor necrosis factor α stimulated gene 6 (TSG-6) has anti-inflammatory effect, and the scar formation can be inhibited by local injection of TSG-6 protein at the early stage of trauma. However, the mechanism of this effect is still unclear. OBJECTIVE:To construct the lentiviral expression vector and shRNA vector for human TSG-6, with stable overexpression, transfection and interference, and to explore the effect of TSG-6 on proliferation and apoptosis of keloid fibroblast cell lines.  METHODS:Human keloid fibroblast cells were isolated from the keloid’s tissue by enzyme digestion and identified by immunocytochemistry assay. Lentiviral vectors pLVX-puro-TSG-6 and pLVX-shRNA1-TSG-6 were constructed and transfected into human keloid fibroblast, exclusively. Expression levels of TSG-6 mRNA and protein were detected by RT-PCR and western blot assay. MTT assay and flow cytometry were used to estimate the cell proliferation and apoptosis in each group after transfection. In addition, expression of Bcl-2, p53 and active-caspase-3 were detected by western blot assay in each group. RESULTS AND CONCLUSION: (1) Human keloid fibroblasts were separated successfully. Under the light microscope, cells were spindle. Immunohistochemical staining for vimentin was performed in the fifth passage of cells, with the positive rate of 100%. Cells were negative for cytokeratin. (2) Recombinant lentiviral vectors and stably transfected cell lines were successfully established. TSG-6 gene expression was altered apparently. Compared with the control group, cell proliferation was delayed and apoptotic rate was noticeably increased in TSG-6 gene overexpression group. Cell proliferation increased and apoptotic rate decreased in the TSG-6 gene intervention group (P < 0.05). (3) Western blot assay results demonstrated that Bcl-2 expression reduced, P53 and Active-caspase-3 expression significantly increased in the TSG-6 gene overexpression group (P < 0.05). (4) These finding showed that TSG-6 could inhibit proliferation and induce apoptosis in keloid fibroblasts. Its mechanism may be associated with the down-regulation of Bcl-2 protein expression, up-regulation of P53 protein expression and increased Caspase-3 activity. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

9.
BACKGROUND: Whether continuous passive motion improves osteoarthritis by enhancing the proliferation ability of chondrocytes is rarely reported. OBJECTIVE: To analyze the therapeutic outcomes of continuous passive motion in rabbits with osteoarthritis and the underlying mechanism. METHODS: Thirty-six New Zealand white rabbits were randomly allotted into three groups (n=12 per group). Rabbits in control group only underwent capsulotomy with no harm to the cartilage; osteoarthritis models were established in the rabbits of model and treatment groups using Hulth method. At 1 day after modeling, the treatment group rabbits were treated with continuous passive motion, 8 hours daily for consecutive 8 weeks. Interleukin-1 and tumor necrosis factor α levels in the synovial fluid were detected by ELISA; collagen type II expression and the proliferation ability of chondrocytes were detected by MTT assay; Erk signaling pathway activation was determined using western blot assay. RESULTS AND CONCLUSION:In the model group, interleukin-1 and tumor necrosis factor α levels in the synovial fluid were significantly increased, and the expression level of collagen type II mRNA was remarkablely down-regulated. Continuous passive motion significantly downregulated interleukin-1 and tumor necrosis factor α levels and up-regulated the collagen type II mRNA level (P < 0.01). The model group showed significantly decreased proliferation ability of chondrocytes and down-regulated Erk signaling pathway activation, while after continuous passive motion, all above indicators were significantly improved (P < 0.01). These results indicate that the continuous passive motion can alleviate osteoarthritis probably by influencing interleukin-1 and tumor necrosis factor α levels, proliferation ability of chondrocytes, and collagen type II expression, as well as regulating Erk signaling pathway activation. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

10.
BACKGROUND:Low power microwave irradiation has been shown to promote the healing of fractures with internal fixation; however, its action mechanisms on the skeletal muscle around the fracture site are unclear. OBJECTIVE:To study the effects of low power microwave irradiation (20 W) on the proliferation ability of skeletal muscle satellite cells in a rabbit model of femoral fracture with internal fixation. METHODS:Forty male New Zealand rabbits were used to establish femoral fracture followed by internal fixation models, and then were equally randomized into spontaneous recovery and microwave treatment groups. Low power microwave irradiation (20 W) was given for 30 consecutive days in the microwave treatment group on day 4 after modeling, while no microwave irradiation was given in the spontaneous recovery group. Rabbit thigh muscles adjacent to the implant were obtained to isolate skeletal muscle satellite cells. Immunohistochemical staining, hematoxylin-eosin staining and quantitative RT-PCR were used to evaluate the ability of the proliferation and differentiation of skeletal muscle satellite cells. RESULTS AND CONCLUSON: Hematoxylin-eosin staining showed that there was no significant difference in the morphology and histology of skeletal muscle tissues between the spontaneous recovery and microwave treatment groups. However, the relative mRNA expression of MyoG in the cultured skeletal muscle satellite cells in vitro and the number of α-sarcometric actin-postive cells in the microwave treatment group were significantly increased compared with the spontaneous recovery group (P < 0.05). The proliferative ability of skeletal muscle satellite cells was inhibited at the early stage, but not at the later stage. Our results suggest that low power microwave irradiation (20 W) can promote the proliferation and differentiation of skeletal muscle satellite cells around the implant in a rabbit model of femoral fracture with internal fixation, and thereby confirm the efficacy and safety of low power microwave irradiation for the internal fixation of fractures. 中国组织工程研究杂志出版内容重点:组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程  相似文献   

11.
Renal dysplasia and asplenia in two sibs   总被引:2,自引:0,他引:2  
A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.  相似文献   

12.
Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc2 (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.  相似文献   

13.
About 1900, modern food selection and processing caused widespread epidemics of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a panhypovitaminosis B, i.e., a mixture of substrate beriberi and substrate pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse endemic disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for primates. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.  相似文献   

14.
There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.  相似文献   

15.
16.
Newton H 《Medical history》2011,55(2):153-182
Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.  相似文献   

17.
Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.  相似文献   

18.
HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.  相似文献   

19.
The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.  相似文献   

20.
Starting with the integument, we see many organs are contractile sacs or multiples thereof, which tubes or bags constitute the major part of the entire body. Recognition of this basic unit and its characteristics sheds new light, individually and collectively, on many disorders previously considered unrelated. Muscular tears and perforations develop in the walls of these chambers, being no way peculiar to those organs, wherein, hydrochloric acid occurs. So, it is not necessary to explain the absence of excessive acid from patients who exhibit holes in the gastric, uterine, aortic, duodenal, rectal, pulmonary, retina, and other walls. Muscle, not acid is the great common factor relating idiopathic disorders in the gastrointestinal tract to each other and to similar diseases in other systems. When the units are linked together, the lesions tend to appear as arthropathies, i.e. at the joints. Rephrasing common-place observations, frees us from conventional, conceptual cul-de-sacs. An observation is only as good as its interpretation, so all possibilities must be considered, otherwise, we will remain blinded by our misconceptions.  相似文献   

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