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排序方式: 共有2137条查询结果,搜索用时 10 毫秒
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Daniel Buser Britt Hoffmann Jeanpierre Bernard Adrian Lussi Daniel Mettler Robert K. Schenk 《Clinical oral implants research》1998,9(3):137-150
In recent years, bone grafts and bone substitutes have been increasingly utilized underneath barrier membranes to optimize the treatment outcome of bone reconstructive therapy for defects in the alveolar process. In the present study, 4 different filling materials were evaluated in bone defects of similar dimensions in the mandible of miniature pigs. Blood clots and autografts were used as controls. The defects were covered with barrier membranes and allowed to heal for 4, 12 or 24 weeks. Histologic examination demonstrated that bone repair progressed through a programmed sequence of maturation steps closely resembling the pattern of bone development and growth regardless of whether bone grafts or substitutes were present or not. Histomorphometric analysis showed that autologous bone grafts (autografts) had the best osteoconductive properties during the initial healing period, with 39% of newly formed bone inside the membrane-covered defects at 4 weeks of healing. In addition, 87% of the graft surfaces were already covered by bone at this time. Both values were significantly higher for autografts than for the 4 alternative bone fillers (P < or = 0.05). At 12 weeks, these differences were no longer apparent, with all 5 filling materials showing similar values. Among the tested bone substitutes, tricalcium phosphate (TCP) showed a significantly higher percentage of bone fill at 24 weeks of healing. It can be concluded that sites filled with autografts clearly demonstrated the best results underneath barrier membranes in the early phase of healing. As far as degradation and substitution are concerned, TCP showed the most promising results. This filler, however, needs to be tested further in a more demanding animal model. Less favorable results were obtained for coral-derived hydroxyapatite granules and for demineralized freeze-dried bone allografts. 相似文献
3.
Light-emitting diodes (LEDs), mounted in drilled holes in the perimeter bowl, are used as stimuli in several automated perimeters. A concern is that these "black holes" might interrupt the otherwise uniform background illumination and cause inconsistent test results. A Dicon perimeter was modified by covering some of the LEDs with diffusing plastic. One eye of 41 normal volunteers was tested repetitively within the central 5 degrees of the visual field at the same 12 locations with both covered and uncovered LED stimuli. Higher variances of multiple threshold determinations were observed, significant at the 0.0005 level, when testing was done with uncovered LEDs. On average, the black hole effect contributed 0.8 dB to short-term fluctuation. The black hole effect is probably of minor clinical importance except in exacting quantitative perimetry. 相似文献
4.
Alexander Yu Donald Turbiville Fangling Xu Joseph W. Ray Allison D. Britt Pamela J. Lupo Sunil K. Jain Karen E. Shattuck Sally S. Robinson Jianli Dong 《American journal of medical genetics. Part A》2019,179(11):2178-2189
Duplications in the 22q11.2 region can cause 22q11.2 duplication syndrome and encompass a variety of phenotypes including developmental delays, facial abnormalities, cardiovascular defects, central nervous system delays, and other congenital abnormalities. However, the contribution of these contiguous duplicated regions to the clinical phenotypes has not been fully elucidated. In this study, we identified nine patients carrying different 22q11.2 microduplications detected by chromosomal microarray. Of these patients, seven pediatric patients presented with various clinical features including two neonate cases died shortly after birth, and two healthy adults. We examined region specific genotype–phenotype associations and found unpredictability associated with 22q11.2 duplications in these nine patients. 相似文献
5.
Attenuated poxvirus expressing three immunodominant CMV antigens as a vaccine strategy for CMV infection. 总被引:2,自引:0,他引:2
Zhongde Wang Corinna La Rosa Simon F Lacey Rebecca Maas Shahram Mekhoubad William J Britt Don J Diamond 《Journal of clinical virology》2006,35(3):324-331
BACKGROUND: Human cytomegalovirus (CMV) infection is an important risk factor in the post-transplant (Tx) recovery phase for both hematopoietic stem cell Tx (HSCT) and solid organ Tx (SOT) recipients. CMV infection may be prevented or controlled by simultaneously inducing both CMV-specific neutralizing antibody (nAb) and cellular immunity. Soluble (s) UL55 (surface glycoprotein), UL83 (tegument protein) and UL123/e4 (nuclear protein) are immunodominant in eliciting both CMV nAb and cellular immunity. An attenuated poxvirus, modified vaccinia Ankara (MVA) was selected to develop this vaccine strategy in Tx recipients, because of its clinical safety record, large foreign gene capacity, and capability to activate strong humoral and cellular immune responses against recombinant antigens. OBJECTIVES: A subunit vaccine that targets multiple CMV antigens will be used to gain maximal coverage and protective function against CMV infection. rMVA simultaneously expressing sUL55, UL83 and UL123/e4 will be generated, and humoral and cellular immunity it elicits will be characterized, after murine immunization and in vitro to amplify clinical recall responses. STUDY DESIGN: rMVA will be constructed in two steps using UL123/e4-pLW22 followed by sUL55-UL83-pLW51 transfer plasmids. Western blots will be used to characterize expression levels of each antigen. Primary immunity will be evaluated in mouse models, while recall responses to the virally expressed CMV antigens will be assessed in human peripheral blood. RESULTS: We generated CMV-MVA via homologous recombination, and demonstrated high expression levels of sUL55, UL83 and UL123/e4 by Western blot. CMV-MVA immunization potently induced both humoral and cellular immunity to sUL55, UL83 and UL123 after murine immunization, and cellular immunity to UL83 and UL123 by in vitro amplification of T cell recall responses in human PBMC. CONCLUSIONS: rMVA promotes high level expression of three immunodominant CMV antigens, which is reflected in results of immunization studies in which high titers of UL55-specific antibodies and CD4+ T-help are detected, as well as high levels of UL83-specific and moderate levels of UL123-specific CD8+ CTL. 相似文献
6.
May Britt Kalvenes Reinhardt Fl Karl-Henning Kalland Gunnar Haukenes 《Journal of medical virology》1994,44(1):30-36
Patients with autoimmune chronic active hepatitis (AICAH) and certain other chronic liver disorders often have very high titres of haemagglutination -inhibition (HI) antibodies to rubella virus. In this study it is shown, using floatation centrifugation, that the high rubella HI reactivity is not caused by nonspecific lipoprotein inhibitors but rather by antibodies specific for the rubella haemagglutinin (E1 glycoprotein). After sucrose density gradient ultracentrifugation of sera the major HI reactivity was recovered in the IgG containing fractions. The IgG antibody fraction was strongly reactive by an indirect enzyme-linked immunosorbent assay (ELISA). Higher prevalence and titres of rubella antibodies were also demonstrated by the complement fixation (CF) test using a haemagglutinin-free antigen, and by an indirect haemagglutination (IHA) test (Rubacell) using a cell-associated antigen which is distinct from the antigens used in the HI and CF tests. This high rubella antibody response is therefore demonstrated using three distinct antigen-antibody systems. By means of absorption experiments and radioimmunoprecipitation assays the coating antigen used in the IHA test was shown to reside in the E2 glycoprotein. The cause of this enhanced antibody response to rubella virus structural proteins remains elusive. © 1994 Wiley-Liss, Inc. 相似文献
7.
Unitary discharge patterns (peristimulus time histograms or PSTH) and synaptic events were studies with intracellular recording techniques in 164 cat cochlear nucleus cells to steady-frequency tone bursts 250 ms in duration. There were four response types defined on the basis of the shape of the discharge patterns to tones at the characteristic or best frequency. Primarylike units resemble eighth nerve fibres and have a maximum discharge at tone onset, followed by a smooth decline to a steady level of activity. Buildup units have a transient response at tone onset, followed a period of little or not activity before gradually increasing their discharge rate for the remainder of the tone burst. Onset units have an initial burst of spikes at the onset, with little or no activity for the remainder of the tone burst. Pause units have a long latency (10-30 ms) between tone onset and the appearance of low levels of unit activity, which then gradually increase in rate for the remainder of the tone burst. Changes in signal frequency or intensity within the excitatory response area did not modify response patterns of primarylike and onset units, but could evoke primarylike patterns in buildup and pause units. Inhibition manifested by suppression of spontaneous activity and membrane hyperpolarization were of three kinds: 1) in response to signals at the edges of the excitatory response area (i.e., the inhibitory surround) and detected in onset buildup, and pause units but not in primarylike units; 2) occurring at the offset of tones in the excitatory response area and detected in all four types of cochlear nucleus cells; 3) during excitatory tone bursts in onset and buildup units associated with the periods of suppressed unit activity. Membrane hyperpolarization did not accompany the delay in unit activity after tone onset in pause units. Inhibitory events in cochlear nucleus cells provide mechanisms for producing diversity in the temporal pattern of discharges to acoustic signals which may underly the encoding of complex features of sounds. 相似文献
8.
Aanesen Fiona Øiestad Britt Elin Grotle Margreth Løchting Ida Solli Rune Sowden Gail Wynne-Jones Gwenllian Storheim Kjersti Eik Hedda 《Journal of occupational rehabilitation》2022,32(2):306-318
Journal of Occupational Rehabilitation - Purpose To perform a process evaluation of a stratified vocational advice intervention (SVAI), delivered by physiotherapists in primary care, for people on... 相似文献
9.
Konrd S. Konrdsson Lars Holme Nielsen Bjrn I. R. Carlborg Britt Borgkvist 《The Laryngoscope》2000,110(2):264-264
Objectives: To elucidate the pressure transfer between intracranial and labyrinthine fluids in patients with well‐defined unilateral Meniere's disease. Study Design: Eleven patients previously exposed to hypobaric pressure agreed to be investigated further with the tympanic membrane displacement (TMD) technique. TMD was used to indirectly analyze perilymph pressure changes as the result of changes in body position. Methods: Repeated measurements for both the diseased and the healthy ears were made with the patients supine and then in a sitting position. The TMD parameters for the maximum inward displacement, the Vi, and the mean volume displacement, the Vm, were calculated and compared. Results: The paired comparison showed statistically significant larger Vi values for both ears in the supine position. A similar tendency was observed for the Vm value. This difference of the Vi was significantly larger for the diseased ear compared with the currently healthy ear. The results were compared to the audiometric and electrocochleographic results previously obtained on the same patients when they were subjected to hypobaric pressure. Patients who experienced the largest differences in hearing level thresholds in the lower frequencies also showed the greatest differences in TMD values as the result of postural changes. Conclusions: Despite the limited number, the statistically supported results suggest a relation between the efficiency of the routes of pressure transfer and the observed effect of hypobaric exposure. The results also indicate that for the patients tested, the routes of communication are more effective in the diseased ear than in the healthy ear—a condition that may relate to the pathogeneses of Meniere's disease. 相似文献
10.
Amber Bolli Bede Nriagu Allison D. Britt Anjali D. Toole James Treat Abhay Srinivasan Sarah E. Sheppard 《American journal of medical genetics. Part A》2023,191(5):1442-1446
Capillary malformations are slow-flow vascular malformations that affect the microcirculation including capillaries and post capillary venules and can be associated with growth differences. Specifically, the association of capillary malformations with undergrowth is a vastly understudied vascular syndrome with few reports of genetic causes including PIK3CA, GNAQ, and GNA11. Recently, a somatic pathogenic variant in AKT3 was identified in one child with a cutaneous vascular syndrome similar to cutis marmorata telangiectatica congenita, undergrowth, and no neurodevelopmental features. Here, we present a male patient with a capillary malformation and undergrowth due to a somatic pathogenic variant in AKT3 to confirm this association. It is essential to consider that mosaic pathogenic variants in AKT3 can cause a wide spectrum of disease. There is a need for future studies focusing on capillary malformations with undergrowth to understand the underlying mechanism. 相似文献