Cytological study of copper in oral submucous fibrosis.

BACKGROUND: Habitual arecanut chewing is associated with Oral Submucous Fibrosis (OSF). High copper content in arecanut plays a vital role in pathogenesis of OSF. This study evaluates the copper-staining pattern of buccal epithelial cells in oral cytological smears of non-chewers, chewers, and OSF. MATERIALS & METHODS: Alcohol fixed buccal epithelial smears of 10 histopathologically confirmed cases of OSF, 10 chewers without lesion, and 5 nonchewers were stained with modified Rhodamine technique and studied under the light microscope. Buccal epithelial smears of non-chewers dipped in copper sulphate solution were used as known positive for copper. RESULT: Copper appeared as shades of palered within the cytoplasm of chewers and did not show any stain in non-chewers. Intense red stain was seen in OSF smears as dark granules within the cytoplasm. CONCLUSION: Intense staining of copper in OSF buccal smears, than in the chewers supports the role of copper in the pathogenesis of OSF.     

Osteogenic differentiation of human bone marrow stromal cells on partially demineralized bone scaffolds in vitro

Tissue engineering has been used to enhance the utility of biomaterials for clinical bone repair by the incorporation of an osteogenic cell source into a scaffold followed by the in vitro promotion of osteogenic differentiation before host implantation. In this study, three-dimensional, partially demineralized bone scaffolds were investigated for their ability to support osteogenic differentiation of human bone marrow stromal cells (BMSCs) in vitro. Dynamic cell seeding resulted in homogeneous cell attachment and infiltration within the matrix and produced significantly higher seeding efficiencies when compared with a conventional static seeding method. Dynamically seeded scaffolds were cultured for 7 and 14 days in the presence of dexamethasone and evaluated on biochemical, molecular, and morphological levels for osteogenic differentiation. Significant elevation in alkaline phosphatase activity was observed versus controls over the 14-day culture, with a transient peak indicative of early mineralization on day 7. On the basis of RT-PCR, dexamethasone-treated samples showed elevations in alkaline phosphatase and osteocalcin expression levels at 7 and 14 days over nontreated controls, while bone sialoprotein was produced only in the presence of dexamethasone at 14 days. Scanning electron microscopy evaluation of dexamethasone-treated samples at 14 days revealed primarily cuboidal cells indicative of mature osteoblasts, in contrast to nontreated controls displaying a majority of cells with a fibroblastic cell morphology. These results demonstrate that partially demineralized bone can be successfully used with human BMSCs to support osteogenic differentiation in vitro. This osseous biomaterial may offer new potential benefits as a tool for clinical bone replacement.     

Performance of hydroxyapatite bone repair scaffolds created via three-dimensional fabrication techniques

The current study analyzes the in vivo performance of porous sintered hydroxyapatite (HA) bone repair scaffolds fabricated using the TheriForm solid freeform fabrication process. Porous HA scaffolds with engineered macroscopic channels had a significantly higher percentage of new bone area compared with porous HA scaffolds without channels in a rabbit calvarial defect model at an 8-week time point. An unexpected finding was the unusually large amount of new bone within the base material structure, which contained pores less than 20 microm in size. Compared with composite scaffolds of 80% polylactic-co-glycolic acid and 20% beta-tricalcium phosphate with the same macroscopic architecture as evaluated in a previous study, the porous HA scaffolds with channels had a significantly higher percentage of new bone area. Therefore, the current study indicates that scaffold geometry, as determined by the fabrication process, can enhance the ability of a ceramic material to accelerate healing of calvarial defects.     

Intrathoracic pressure fluctuations move blood during CPR: Comparison of hemodynamic data with predictions from a mathematical model

Whether blood flow during cardiopulmonary resuscitation (CPR) results from intrathoracic pressure fluctuations or direct cardiac compression remains controversial. We developed a mathematical model that predicts that blood flow due to intrathoracic pressure fluctuations should be insensitive to compression rate over a wide range but dependent on the applied force and compression duration. If direct compression of the heart plays a major role, however, the model predicts that flow should be dependent on compression rate and force, but above a threshold, insensitive to compression duration. These differences in hemodynamics produced by changes in rate and duration form a basis for determining whether blood flow during CPR results from intrathoracic pressure fluctuations or from direct cardiac compression. The model was validated for direct cardiac compression by studying the hemodynamics of cyclic cardiac deformation following thoracotomy in four anesthetized, 21–32-kg dogs. As predicted by the model, there was no change in myocardial or cerebral perfusion pressures when the duration of compression was increased from 15% to 45% of the cycle at a constant rate of 60/min. There was, however, a significant increase in perfusion pressures when rate was increased from 60 to 150/min at a constant duration of 45%. The model was validated for intrathoracic pressure changes by studying the hemodynamics produced by a thoracic vest (vest CPR) in eight dogs. The vest contained a bladder that was inflated and deflated. Vest CPR changed intrathoracic pressure without direct cardiac compression, since sternal displacement was <0.8 cm. As predicted by the model and opposite to direct cardiac compression, there was no change in perfusion pressures when the rate was increased from 60 to 150/min at a constant duration of 45% of the cycle. Manual CPR was then studied in eight dogs. There was no surgical manipulation of the chest. Myocardial and cerebral blood flows were determined with radioactive microspheres and behaved as predicted from the model of intrathoracic pressure, not direct cardiac compression. At nearly constant peak sternal force (378–426 N), flow was significantly increased when the duration of compression was increased from short (13%–19% of the cycle) to long (40%–47%), at a rate of 60/min. Flow was unchanged, however, for an increase in rate from 60 to 150/min at constant compression duration. In addition, myocardial and cerebral flow correlated with their respective perfusion pressures. Thus vital organ perfusion pressures and flow for manual external chest compression are dependent on the duration of compression, but not on rates of compression of 60 and 150/min. These data are of course similar to those produced by vest CPR, where intrathoracic pressure is manipulated without sternal displacement, and to those predicted for movement of blood by intrathoracic pressure changes. These data are, however, opposite to those produced by cardiac deformation and to those predicted for movement blood by direct cardiac compression. We conclude that intrathoracic pressure fluctuations generate blood flow during manual CPR.     

HLA alleles and haplotypes among the Lakota Sioux: report of the ASHI minority workshops, part III

Human leukocyte antigen (HLA) class I and II alleles were defined for 302 Lakota Sioux American Indians as part of the American Society for Histocompatibility and Immunogenetics coordinated studies on minority populations. The study group was comprised of adult volunteers from the Cheyenne River and Ogala Sioux tribes residing, respectively, on the Cheyenne River and Pine Ridge Reservations in South Dakota. Of the participants, 263 (87%) claimed full American Indian ancestry through both maternal and paternal grandparents. The study group included 25 nuclear families that were informative for genotyping. HLA phenotypes from 202 adults with no other known first-degree relative included in the study were used for calculation of allele and haplotype frequencies by maximum likelihood estimation. HLA-A, -B, and -Cw alleles were found to be in Hardy Weinberg equilibrium. Deviation from equilibrium was observed for DRB1 alleles (p=0.01), but could be attributed to the sample size and the occurrence of some genotypes with low expected frequencies. Polymorphism among the Sioux was limited with four to seven alleles comprising >80% of those observed at each locus. Several alleles were found at high frequency (0.05-0.30) among the Sioux that are also prevalent in other Native Americans and Alaska Natives, including: A*2402, *3101, and *0206; B*3501,*3901, *5101, and *2705; Cw*0702, *0404, and *03041; DRB1*0407, *0404, *1402, and *16021; and DQB1*0301, *0302, and *0402. DRB1*0811, which has been only previously described in Navajo and Tlingit Indians, was found to occur at a frequency of 0.119 among the Sioux. Two new alleles were defined among the Sioux: Cw*0204 and DRB1*040703, which were found in two and four individuals, respectively. In the haplotype analyses, significant linkage disequilibrium (p<0.00001) was seen in all pairwise comparisons of loci and numerous two and three locus haplotypes were found to have strong, positive linkage disequilibrium values. The two most common extended haplotypes among the Sioux, determined by maximum likelihood estimation and genotyping were: A*31012, B*3501, Cw*0404, DRB1*0407; and A*24021, B*3501, Cw*0404, DRB1*0404.     

Engineered cellular response to scaffold architecture in a rabbit trephine defect

Tight control of pore architecture in porous scaffolds for bone repair is critical for a fully elucidated tissue response. Solid freeform fabrication (SFF) enables construction of scaffolds with tightly controlled pore architecture. Four types of porous scaffolds were constructed using SFF and evaluated in an 8-mm rabbit trephine defect at 8 and 16 weeks (n = 6): a lactide/glycolide (50:50) copolymer scaffold with 20% w/w tri-calcium phosphate and random porous architecture (Group 1); another identical design made from poly(desaminotyrosyl-tyrosine ethyl ester carbonate) [poly(DTE carbonate)], a tyrosine-derived pseudo-polyamino acid (Group 2); and two poly(DTE carbonate) scaffolds containing 500 microm pores separated by 500-microm thick walls, one type with solid walls (Group 3), and one type with microporous walls (Group 4). A commercially available coralline scaffold (Interpore) with a 486-microm average pore size and empty defects were used as controls. There was no significant difference in the overall amount of bone ingrowth in any of the devices, as found by radiographic analysis, but patterns of bone formation matched the morphology of the scaffold. These results suggest that controlled scaffold architecture can be superimposed on biomaterial composition to design and construct scaffolds with improved fill time.     

Congenital heart defects in CHARGE: The molecular role of CHD7 and effects on cardiac phenotype and clinical outcomes

CHARGE syndrome is characterized by a pattern of congenital anomalies (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth, Genital abnormalities, and Ear abnormalities). De novo mutations of chromodomain helicase DNA binding protein 7 (CHD7) are the primary cause of CHARGE syndrome. The clinical phenotype is highly variable including a wide spectrum of congenital heart defects. Here, we review the range of congenital heart defects and the molecular effects of CHD7 on cardiovascular development that lead to an over‐representation of atrioventricular septal, conotruncal, and aortic arch defects in CHARGE syndrome. Further, we review the overlap of cardiovascular and noncardiovascular comorbidities present in CHARGE and their impact on the peri‐operative morbidity and mortality in individuals with CHARGE syndrome.