Biomedical subjects
Publications and source records attributed to L Yao.
Interleukin-8 (IL-8) plays a crucial role in the migration of neutrophils to bacterium-infected sites. This study investigated IL-8 induction in Staphylococcus aureus-infected endothelial cells (EC). We observed that S. aureus-infected EC were induced to express both IL-8 mRNA and protein, which can promote transmigration of neutrophils across an EC monolayer.
Degenerative plantar plate failure is an under-recognized cause of lesser metatarsalgia. We performed magnetic resonance imaging (MRI) with a small receiver coil in 13 patients in whom plantar plate ruptures of the second or third metatarsophalangeal joint were clinically suspected. In eight patients, MRI showed focal hyperintensity in the plantar plate that was interpreted as a rupture of the plate. Ruptures were confirmed in all five patients who underwent an operative procedure to treat the unstable, painful metatarsophalangeal joint. MRI is a noninvasive technique that can visualize plantar plate abnormalities and aid the clinical evaluation of problematic lesser metatarsalgia.
Using radiographs and diagrams, this article reviews the most commonly used axes and angles of the foot, including: longitudinal axis of the rearfoot, collum tali axis, talocalcaneal angle, cuboid abduction angle, longitudinal axis of the lesser tarsus, lesser tarsus angle, talonavicular angle, longitudinal axis of the metatarsus, forefoot adductus angle, metatarsus adductus angle, first intermetatarsal angle, hallux valgus angle, proximal and distal articular set angles, and hallux interphalangeal angle, plane of support, collum tali axis, talar declination angle, calcaneal inclination axis, lateral talocalcaneal angle, first metatarsal declination axis and calcaneal inclination angle.
OBJECTIVE: This study describes the clinical presentation and the course of Ribbing disease in six patients and illustrates imaging features on plain radiography, conventional and computed tomography, and 99mTc-methylene diphosphonate bone scans. MATERIALS AND METHODS: Between 1982 and 1990, six female patients presented with painful bony lesions that were believed to be Ribbing disease. Ten bones were affected: both tibiae in three patients, a unilateral tibia in one, both femora in one, and a unilateral femur in one. Plain radiographs and either conventional or computed tomography were available for all patients and 99mTc-methylene diphosphonate bone scans, for five patients. All patients underwent open biopsy and/or surgical decompression. RESULTS: The diagnosis was reached in all patients through a combination of clinical findings (lack of systemic signs of infection or laboratory values suggesting metabolic bone disease), imaging, histologic evaluation, and specimen cultures. Radiographs and tomographic studies showed benign-appearing endosteal and periosteal cortical thickening. Intense uptake of radionuclide tracer was confined to the shaft of all involved bones. All pathologic specimens revealed nonspecific changes that included a slow increase in the mass of cortical and endosteal bone. These specimens also assisted in excluding neoplastic or infectious causes for the new bone formation. CONCLUSION: Ribbing disease is a rare disorder that, on imaging studies, may simulate stress fracture, chronic infection, bone-forming neoplasia, or a systemic metabolic or endocrine disorder. Clinical and imaging features may suggest the correct diagnosis.
111 adult patients hospitalized with lower extremity fracture (LEF) at three teaching hospitals of Beijing Medical University were interviewed by using STAI and CES-D. The results showed that the prevalence of depression in this group using CES-D is 69.4%, and there was a high correlation between STAI scores and CES-D scores. Multivariante analyses indicated that physical status, financial crisis, age, knowledge about disease, especially the patients' perceived threat of fracture, and social supports were the main factors that contribute to the patients' emotional distress.
Cross-linking of the high-affinity IgE receptor (Fc epsilon RI) on mast cells induces rapid phosphorylation on serine, threonine, and tyrosine residues and increases the enzymatic activity, of a Tec subfamily tyrosine kinase, Itk/Tsk/Emt (Emt). The pleckstrin homology domain of Emt at its amino-terminal interacts directly with multiple isoforms of protein kinase C (PKC) in vitro. In addition, a portion of Emt is physically associated with multiple isoforms of PKC in intact mast cells. PKC phosphorylates a bacterial fusion protein containing the pleckstrin homology domain of Emt in vitro. Coexpression of Emt in COS-7 cells with Ca(2+)-dependent PKC isoforms (alpha, beta I, or beta II) induces an enhancement in tyrosine phosphorylation of Emt. In vivo inhibition of PKC expression or activity attenuates tyrosine phosphorylation and enzymatic activity of Emt induced upon Fc epsilon RI cross-linking. These data collectively suggest that PKC phosphorylates Emt and activates its autophosphorylating activity. Alternatively, PKC could activate another tyrosine kinase that phosphorylates Emt, or PKC-mediated phosphorylation of Emt may render it a target for another tyrosine kinase. In any case, PKC appears to play a major role in the activation of Emt induced upon Fc epsilon RI cross-linking.
Conventional magnetic resonance images are reconstructed by Fourier transformation and have uniform spatial resolution across the entire field of view (FOV). This paper describes a way of creating MR images that have higher spatial resolution in some areas than in others. High resolution imaging can be confined to just those areas where it is necessary to resolve strong edges without truncation artifact. Such locally focused images can be acquired in less scan time than that required to image the entire FOV with uniformly high resolution. Images are reconstructed from a subset of the usual phase-encoded signals required to create a uniformly well-resolved image. The measured signals are usually nonuniformly scattered in k-space. Functional and interventional imaging may benefit from this technique, which makes it possible to acquire a rapid series of dynamical images that have high resolution in areas of expected change and lower resolution elsewhere. Spectroscopic images may be improved by using high resolution in the neighborhood of sharp edges (e.g., scalp lipids) that might otherwise cause truncation artifacts.
PURPOSE: We sought to clarify the ability of magnetic resonance imaging (MR) to show partial anterior cruciate ligament (ACL) ruptures and to allow distinction of partial from complete ACL ruptures. MATERIALS AND METHODS: Eighty-eight patients were studied by arthroscopy and MR (36 with normal ACLs, 21 with partial ACL ruptures, and 31 with complete ACL ruptures). MR studies were interpreted by an experienced, blinded reader. MR examinations were also independently scored with respect to four primary and seven secondary signs, and these data were analyzed using discriminant analysis. RESULTS: The sensitivity of MR is lower for partial than for complete ACL ruptures. Most detected partial ACL ruptures resemble complete ruptures on MR. Secondary signs do not significantly improve detection of partial ACL ruptures, but they do help to distinguish partial from complete ACL ruptures. Displacement of the posterior horn of the lateral meniscus and popliteus muscle injury are indicative of complete ACL rupture. CONCLUSIONS: The majority of partial ACL ruptures are shown by MR, but MR is less sensitive for partial than for complete ACL rupture. The distinction of partial from complete ACL rupture on MR examination, while problematic, is slightly improved by assessment of secondary signs.
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The ability of the vascular endothelium to elaborate cytokines in response to gram-positive sepsis has received limited attention. This study examined cytokine expression by human umbilical vein endothelial cells (EC) following infection with a gram-positive bacterial pathogen, Staphylococcus aureus. S. aureus infection of EC resulted in the production of interleukin-6 (IL-6) and IL-1 beta. For IL-6, message was detected at 3 h after infection, protein was present at 24 h, and both message and protein persisted for 72 h. IL-1 beta message was detected at 12 h, IL-1 beta protein was detected at 24 h, and both persisted for 72 h. Message for colony-stimulating factor 1 remained unaltered. UV-killed S. aureus also elicited IL-1 beta and IL-6 message and protein expression at 24 and 48 h. Twenty-one clinical isolates of S. aureus were tested, and all induced IL-6 release by 48 h. However, the laboratory strain 8325-4 did not induce cytokine expression at any time point and was internalized by EC 1,000-fold less than other strains were. Internalization of latex beads by EC did not induce IL-6 gene expression. Furthermore, cytochalasin D treatment of the EC prevented IL-1 and IL-6 induction by S. aureus but not by tumor necrosis factor alpha or lipopolysaccharide. These results indicate that S. aureus is a potent inducer of IL-1 and IL-6 in EC and that internalization of S. aureus by EC is necessary for their cytokine expression. Thus, our data suggest that the vascular endothelium may play an important role in the pathogenesis of septicemia caused by gram-positive organisms.
PURPOSE: To describe the epidemiologic, clinical, and imaging features of cat-scratch disease (CSD) to facilitate prompt recognition and noninvasive diagnosis of this condition. MATERIALS AND METHODS: Eight otherwise healthy patients with pet cats presented with the subacute onset of epitrochlear, axillary, or groin masses. All underwent cross-sectional imaging with computed tomography (CT) (n = 1) or magnetic resonance (MR) imaging (n = 7). Five patients underwent radiography of the elbow. RESULTS: In all patients, MR imaging and CT showed a poorly defined soft-tissue mass with extensive surrounding edema in an efferent lymphatic distribution. Radiography revealed only soft-tissue edema in two patients and an ill-defined soft-tissue mass with soft-tissue edema in three patients. Six patients underwent biopsy; the findings of all pathologic specimens supported the diagnosis of CSD. No patients underwent serologic evaluation. All patients were asymptomatic within 4 weeks of beginning antibiotic therapy. CONCLUSION: CSD should be considered in all patients with upper extremity or head and neck adenopathy and a history of cat exposure. Although generally not required for diagnosis, cross-sectional imaging will reveal a mass with surrounding edema in an area of lymphatic drainage.
Proliferating cell nuclear antigen (PCNA) in a useful marker for monitoring cell proliferation in most species. The immunostaining of PCNA on tissue cryosections, however, has been hampered by a loss of PCNA immunoreactivity during the staining process. The need for both identifying the actual phenotypes of proliferating cells and differentiating them from other tissue components prompted us to establish reliable techniques for PCNA immunostaining on cryosections and to apply these to double immunostainings with other markers. We tested various fixing conditions for rat tissue cryosections and the effect derived from unmasking with pepsin digestion to restore PCNA immunoreactivity after fixation. For single immunostainings, the unmasking was effective in most fixing conditions tested. Particularly, 4% paraformaldehyde/0.05% glutaraldehyde fixation followed by 0.001% pepsin digestion resulted in the strongest immunoreactivity for PCNA and the best morphology, and was the first choice for double immunostainings with relatively stable second antigens. Alternatively, periodate-lysine-paraformaldehyde fixation was also applicable to other second antigens which are labile to the former treatment. These techniques can serve in the collection of important information from frozen tissues regarding the relationship between PCNA and other markers of interest which are usually susceptible to routine formalin and/or paraffin embedding.
There are 3 definitions of acetabular version: true (anatomic) version, planar (radiographic) version, and operative version. Although planar version can be measured on standard radiographs, the measurement may be inaccurate when applied to metal-backed acetabular components. However, another version angle is depicted clearly on an angled, cross-table lateral radiograph of the hip--the axiolateral view, and this angle readily distinguishes anteversion from retroversion. If the angle of the xray beam is known or is standardized, version measured on the axiolateral view can be converted to the other version angles. Nomograms for these conversions are presented. In most cases, acetabular version measured on the axiolateral radiograph closely approximates planar version.
Through forty years' sustained efforts in the prevention and treatment of malaria in Zhejiang Province, the malaria incidence dropped from 76.650/000 in the Fifties to 0.910/000 in the Eighties. Three malaria epidemics emerged in 1954, 1962 and 1973, respectively, among them the epidemic in 1962 was the most serious one with 0.88 million cases reported and an incidence of 3300/000. The annual incidence of the overall counties/cities was below 10/000 after 1988. Only 172 malaria cases were found in 1992, the incidence being 0.040/000. No indigenous malaria case was found in 38 counties in 1992, accounting to 43.7% of the total malaria endemic counties. The number of imported malara cases was 3,829, amounting to 89.2% of the total number of cases. Through the spot-check of the Ministry of Public Health in 1993, it was confirmed that the criteria of basic elimination of malaria in the province was attained.
Bruton tyrosine kinase (EC 2.7.1.112) [Btk, encoded by Btk in mice and BTK in humans (formerly known as atk, BPK, or emb)], which is variously mutated in chromosome X-linked agammaglobulinemia patients and X-linked immunodeficient (xid) mice, has the pleckstrin homology (PH) domain at its amino terminus. The PH domain of Btk expressed as a bacterial fusion protein directly interacts with protein kinase C in mast cell lysates. Evidence was obtained that Btk is physically associated with protein kinase C in intact murine mast cells as well. Both Ca(2+)-dependent (alpha, beta I, and beta II) and Ca(2+)-independent protein kinase C isoforms (epsilon and zeta) in mast cells interact with the PH domain of Btk in vitro, and protein kinase C beta I is associated with Btk in vivo. Btk served as a substrate of protein kinase C, and its enzymatic activity was down-regulated by protein kinase C-mediated phosphorylation. Furthermore, depletion or inhibition of protein kinase C with pharmacological agents resulted in an enhancement of the tyrosine phosphorylation of Btk induced by mast cell activation.
The nerve growth factor (NGF) family of neurotrophins exerts effects by binding to products of the trk family of proto-oncogenes. We examined the expression of both trk and neurotrophin mRNA during the entire range of development of quail dorsal root ganglia (DRG) and sympathetic ganglia (SG) using in situ hybridization and reverse transcriptase-polymerase chain reaction (RT-PCR). TrkC mRNA was present in neurons or their precursors from the time of formation of DRG (stage 18, embryonic day 2.5 [E2.5]) and throughout development. The number of labeled cells changed, however, from a majority to a minority at later developmental stages. Expression of trkA mRNA was not detected in DRG until stage 30 (E6) by in situ hybridization, although results with RT-PCR were positive at stage 23 (E3.5). Labeling was always detected on a majority of neurons or their precursors. SG exhibited low levels of trkC mRNA during the later stages of development, whereas trkA mRNA was present from stage 34 onward in most neurons. We have also shown that NGF, neurotrophin-3 (NT-3), and brain-derived neurotrophic factor (BDNF) mRNA were present at all stages examined (stages 23 through 45 for DRG, stages 35-36 and 45 for SG). In DRG, NGF mRNA expression was limited to support cells, whereas NT-3 and BDNF mRNA were detected in both neurons and support cells. These results suggest that neurotrophins could serve a local function in developing ganglia, which can be correlated with the presence of their respective receptors.
To determine the role of neurotrophins on the initial development of the avian embryo, RT-PCR was used to detect when mRNA for nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3), as well as their respective receptors, trkA, trkB, and trkC, is first expressed in the avian embryo. trkA, BDNF, trkB, NT-3, and trkC mRNA were expressed as early as stage 1 ("prestreak" stage), while NGF mRNA was not expressed until later in development (stage 5, "notochord" stage). Microdissection of Embryonic Day 2 quail (stages 12 to 14) and RT-PCR analysis revealed that the neural crest, neural tube, somites, or notochord all expressed some neurotrophin or trk mRNA. Although a neurotrophin and its appropriate receptor were both often present or absent, in several cases they were present individually, suggesting that they might have either local or target-derived actions.