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Biomedical subjects

Joel A Block

Publications and source records attributed to Joel A Block.

At least 19 recordsLinked to original sources
PubMed2006

A thin-layer model for viscoelastic, stress-relaxation testing of cells using atomic force microscopy: do cell properties reflect metastatic potential?

Atomic force microscopy has rapidly become a valuable tool for quantifying the biophysical properties of single cells. The interpretation of atomic force microscopy-based indentation tests, however, is highly dependent on the use of an appropriate theoretical model of the testing configuration. In this study, a novel, thin-layer viscoelastic model for stress relaxation was developed to quantify the mechanical properties of chondrosarcoma cells in different configurations to examine the hypothesis that viscoelastic properties reflect the metastatic potential and invasiveness of the cell using three well-characterized human chondrosarcoma cell lines (JJ012, FS090, 105KC) that show increasing chondrocytic differentiation and decreasing malignancy, respectively. Single-cell stress relaxation tests were conducted at 2 h and 2 days after plating to determine cell mechanical properties in either spherical or spread morphologies and analyzed using the new theoretical model. At both time points, JJ012 cells had the lowest moduli of the cell lines examined, whereas FS090 typically had the highest. At 2 days, all cells showed an increase in stiffness and a decrease in apparent viscosity compared to the 2-h time point. Fluorescent labeling showed that the F-actin structure in spread cells was significantly different between FS090 cells and JJ012/105KC cells. Taken together with results of previous studies, these findings indicate that cell transformation and tumorigenicity are associated with a decrease in cell modulus and apparent viscosity, suggesting that cell mechanical properties may provide insight into the metastatic potential and invasiveness of a cell.

Actins↗
PubMed2006

Osteogenic protein 1 in synovial fluid from patients with rheumatoid arthritis or osteoarthritis: relationship with disease and levels of hyaluronan and antigenic keratan sulfate.

The measurement of body fluid levels of biochemical markers in joint tissues has begun to provide clinically useful information. Synovial fluid (SF) plays an important role in articular joint lubrication, nutrition, and metabolism of cartilage and other connective tissues within the joint. The purpose of our study was to identify and characterize osteogenic protein 1 (OP-1) in SF from patients with rheumatoid arthritis (RA) or with osteoarthritis (OA) and to correlate levels of OP-1 with those of hyaluronan (HA) and antigenic keratan sulfate (AgKS). SF was aspirated from the knees of patients with either RA or OA and from the knees of asymptomatic organ donors with no documented history of joint disease. The presence of detectable OP-1 in SF was demonstrated by western blots with specific anti-pro-OP-1 and anti-mature OP-1 antibodies. Measurement of levels of OP-1, HA and AgKS was performed using ELISAs. OP-1 was identified in human SF in two forms, pro-OP-1 and active (mature) OP-1--mature OP-1 being detected only in SF from OA patients and RA patients. Levels of OP-1 and HA were higher in RA patients than in OA patients and asymptomatic donors, while the level of AgKS was highest in SF from asymptomatic donors. Statistically significant differences were found between SF levels of OP-1 in RA and OA patients and between SF levels of AgKS among the three groups tested. The SF content of OP-1 tended to correlate positively with HA levels, but negatively with AgKS concentrations. In conclusion, the results of this study suggest that measurement of OP-1 in joint fluid may have value in the clinical evaluation of joint disease processes.

Arthritis, Rheumatoid↗
PubMed2006

Walking barefoot decreases loading on the lower extremity joints in knee osteoarthritis.

OBJECTIVE: To evaluate the effects that modern shoes have on gait and lower extremity joint loads in osteoarthritis (OA). METHODS: Gait analyses were performed on 75 subjects with knee OA while they were wearing their everyday walking shoes and while they were walking barefoot. The trials involved optoelectronic detection of external markers during ambulation over a multicomponent force plate, and were matched for speed. Comparisons were made of gait parameters and joint loading during trials in which the subjects walked while wearing shoes and while barefoot. RESULTS: Peak joint loads at the hips and knees significantly decreased during barefoot walking, with an 11.9% reduction noted in the knee adduction moment. Stride, cadence, and range of motion at the lower extremity joints also changed significantly, but these changes could not explain the reduction in the peak joint loads. CONCLUSION: Shoes may detrimentally increase loads on the lower extremity joints. Once factors responsible for the differences in loads between with-shoe and barefoot walking are better delineated, modern shoes and walking practices may need to be reevaluated with regard to their effects on the prevalence and progression of OA in our society.

Adult↗
PubMed2006

Knee joint loading differs in individuals with mild compared with moderate medial knee osteoarthritis.

OBJECTIVE: To compare the knee joint loading patterns in individuals with differing radiographic grades of knee osteoarthritis (OA) for characterization of the mechanical implications of different structural states, and to compare the knee adduction angular impulse, a measure of gait complementary to the commonly used peak knee adduction moment. METHODS: Asymptomatic subjects (those without knee OA) having a Kellgren/Lawrence (K/L) radiographic severity grade of 0 or 1 (n = 28) and subjects with symptomatic knee OA having K/L grades of 2 (n = 66) or 3 (n = 23) were recruited. Gait analysis was used to calculate the peak external knee adduction moment and the external knee adduction angular impulse for the whole stance and for the 4 subdivisions of stance. RESULTS: Both the peak knee adduction moment and the knee adduction angular impulse increased with K/L radiographic grade (P < 0.05). However, only the knee adduction angular impulse differed between subjects with moderate (grade 3) and those with mild (grade 2) radiographic knee OA (P < 0.05). CONCLUSION: The differences between mild and moderate symptomatic radiographic knee OA are not only structural but also functional, based on the magnitude of load in the medial knee joint. Moreover, knee adduction angular impulse provides additional information beyond that available from the peak knee adduction moment, and may therefore be an important gait parameter to include in OA research. These findings are important for our understanding of the pathophysiologic mechanisms of OA.

Arthrography↗
PubMed2005

Risk of contralateral avascular necrosis (AVN) after total hip arthroplasty (THA) for non-traumatic AVN.

The risk of developing bilateral disease progressing to total hip arthroplasty (THA) among patients who undergo unilateral THA for non-traumatic avascular necrosis (AVN) remains poorly understood. An analysis of the time-course to contralateral THA, as well as the effects of underlying AVN risk factors, is presented. Forty-seven consecutive patients who underwent THA for AVN were evaluated. Peri-operative and annual post-operative antero-posterior pelvis radiographs were examined for evidence of contralateral involvement. Patient age, weight, height, underlying AVN risk factor(s), date of onset of contralateral hip pain if occurred, and date of contralateral THA if performed, were recorded. Bone scan, computerized tomography and magnetic resonance imaging data were utilized when available. Twenty-one patients (46.6%) underwent contralateral THA for AVN within a median of 9 months after the initial THA (range 0-93, interquartile range 28.5 months). The median follow-up for patients without contralateral THA was 75 months (range 3-109, interquartile range 69 months). Thirty-four patients had radiographic findings of contralateral AVN at study entry; 25 were symptomatic bilaterally at entry and 7 developed contralateral symptoms within a mean time of 12 months (median 10 months, interquartile range 12 months). None of the 13 patients who were free of radiographic evidence of contralateral AVN at study entry developed evidence of AVN during the follow-up. AVN associated with glucocorticoid use was more likely to manifest as bilateral disease than either idiopathic AVN or ethanol-associated AVN (P=0.02 and P=0.03 respectively). Radiographically-evident AVN in the contralateral hip at THA is unlikely to remain asymptomatic for a prolonged period of time. Conversely, asymptomatic contralateral hips without radiographic evidence of AVN are unlikely to develop clinically significant AVN.

Adult↗
PubMed2005

siRNA mediated inhibition of MMP-1 reduces invasive potential of a human chondrosarcoma cell line.

Matrix metalloproteinases (MMPs) play a crucial role in tumor cell invasion and metastasis. Expression of MMP-1 has been reported as a prognostic predictor of recurrence in human chondrosarcoma, and studies using human chondrosarcoma cell lines indicate that MMP-1 expression levels correlate with in vitro invasiveness. These observations suggest that MMP-1 activity has a central role in cell egress from the primary tumor at an early step in the metastatic cascade. In this study, siRNA was used to investigate whether knock down of the MMP-1 gene could be used to inhibit invasiveness in a human chondrosarcoma cell line. The inhibitory effect of siRNA on endogenous MMP-1 gene expression and protein synthesis was demonstrated via RT-PCR, Northern blotting, Western blotting, collagenase activity assay, and an in vitro cell migration assay. The siRNA inhibited MMP-1 expression specifically, since it did not affect the expression of endogenous glyceraldehyde phosphate dehydrogenase (GAPDH) nor other collagenases. Most importantly, the siRNA mediated reduction in MMP-1 expression correlated with a decreased ability of chondrosarcoma cells to invade a Type I collagen matrix. The reduction of invasive behavior demonstrated by human chondrosarcoma cells transfected with MMP-1 siRNA and the specificity of this inhibition supports the hypothesis that this metalloproteinase molecule is involved in initiation of chondrosarcoma metastasis.

Cell Line, Tumor↗
PubMed2005

The effects of minor hip flexion, abduction or adduction and x-ray beam angle on the radiographic joint space width of the hip.

OBJECTIVE: Joint pain may cause patients to hold their limbs in mild flexion, abduction or adduction to minimize pain, regardless of the extent of articular pathology, and these positional changes may have substantial effects on the interpretation of radiographic joint space. We aimed to study the impacts of minor degrees of flexion, abduction or adduction of the hip, as well as the angle of the x-ray beam on the radiographic joint space width (JSW) of the hip joint. METHODS: In the first part of the study, 65 patients (44 males, 21 females, mean+/-SD age 49+/-17) without clinical evidence of hip osteoarthritis (OA) who underwent intravenous pyelography (IVP) were studied. The hips were differentially positioned during the sequential radiographs required for the IVP procedure. Baseline radiographs were taken at 15 degrees internal rotation of the hips [the standard position for anteroposterior (AP) pelvis radiography]; additional positions included the hips at 15 degrees and/or 30 degrees flexion, and 15 degrees adduction and/or 30 degrees abduction. Radiographic JSWs were measured at three sites using a dial caliper: superomedial, superolateral, and the point of narrowest JSW. In the second part, 15 patients without clinical evidence of hip OA who underwent supine abdominal radiography for non-rheumatological indications were evaluated by standard (AP) pelvis x-ray in the same setting and JSW measurements were made as described above. RESULTS: When the average of the three measurements of the JSW was taken for each hip, baseline JSW was 4.38+/-0.55 mm (mean+/-SD). Positioning of the hip significantly (P<0.01) affected the radiographic JSW, with apparent widening during adduction and 30 degrees flexion, (JSW 4.56+/-0.51 mm and 4.53+/-0.58 mm, mean+/-SD), respectively, but narrowing during abduction (4.17+/-0.59 mm, mean+/-SD). Fifteen degree flexion of the hip did not result in statistically significant change in JSW measurements. Upon comparison of the AP pelvis view with the supine abdominal view, neither the average JSW nor the point of narrowest JSW differed significantly, although the superolateral JSW was significantly greater on the AP pelvis view (P=0.02). CONCLUSIONS: Subtle positional changes in the hip, such as may occur during pain or in OA, may artifactually alter the measured radiographic JSW. Thus, longitudinal studies which employ hip JSW to assess disease progression may yield biased results due to changes in pain rather than structure unless care is taken to ensure constant positioning of the hip.

Adult↗
PubMed2005

Thrombotic thrombocytopenic purpura in the setting of systemic sclerosis.

OBJECTIVES: To describe the association between thrombotic thrombocytopenic purpura (TTP) and systemic sclerosis (SSc) and the methods to distinguish TTP from scleroderma renal crisis (SRC). METHODS: A case of TTP that developed in a patient with preexisting SSc is described. Medline/PubMed was searched for literature pertaining to an association between TTP and SSc, with special attention given to distinguishing TTP from SRC. In addition, the role of von Willebrand cleaving protease in the pathogenesis of TTP is reviewed. RESULTS: Including the present case, there have been 9 reports of TTP in association with SSc in the literature. In the majority of these cases TTP presented with features compatible with SRC such as renal dysfunction, thrombocytopenia, hypertension, and microangiopathic hemolytic anemia. Von Willebrand cleaving protease activity is depressed in patients with acute TTP. CONCLUSIONS: TTP in association with SSc has been reported rarely. The diagnosis of TTP, and the distinction from SRC, may be challenging, as these cases may resemble SRC. However, the correct diagnosis is critical because treatment differs substantially for each of these life-threatening conditions. Currently, the assessment of von Willebrand factor cleaving protease activity may assist in making this distinction.

ADAM Proteins↗
PubMed2004

Tuberculosis following the use of etanercept, a tumor necrosis factor inhibitor.

Infliximab, a tumor necrosis factor (TNF) antagonist, is associated with tuberculosis (TB), but it is unknown whether this phenomenon is true of all TNF antagonists. We reviewed 25 cases of TB due to another TNF antagonist, etanercept, that were reported to the US Food and Drug Administration (FDA) between November 1998 and March 2002. Such cases are sometimes incomplete and are subject to underreporting. Fifteen patients received other immunosuppressive medications. The median interval between the receipt of the first dose of etanercept and the diagnosis of TB was 11.5 months. Thirteen patients had extrapulmonary TB at the time of diagnosis. Diagnosis was made on the basis of culture results for 12 patients, biopsy findings for 9, and sputum staining for 4. There were 2 deaths, 1 of which was directly attributed to TB. The estimated number of TB cases reported to the FDA for each person-year of treatment with etanercept (i.e., the "reporting rate") among patients with rheumatoid arthritis (RA) was ~10 cases/100,000 patient-years of exposure. Clinicians considering etanercept for patients with RA should be alert to the possibility of the occurrence of TB, sometimes with an unusual extrapulmonary presentation. It is unclear whether etanercept therapy increases the risk of TB beyond the elevated TB rates already documented for patients with RA.

Adolescent↗
PubMed2004

Information content in Medline record fields.

BACKGROUND: The authors have been conducting text mining analyses (extraction of useful information from text) of Medline records, using Abstracts as the main data source. For literature-based discovery, and other text mining applications as well, all records in a discipline need to be evaluated for determining prior art. Many Medline records do not contain Abstracts, but typically contain Titles and Mesh terms. Substitution of these fields for Abstracts in the non-Abstract records would restore the missing literature to some degree. OBJECTIVES: Determine how well the information content of Title and Mesh fields approximates that of Abstracts in Medline records. APPROACH: Select historical Medline records related to Raynaud's Phenomenon that contain Abstracts. Determine the information content in the Abstract fields through text mining. Then, determine the information content in the Title fields, the Mesh fields, and the combined Title-Mesh fields, and compare with the information content in the Abstracts. RESULTS: Four metrics were used to compare the information content related to Raynaud's Phenomenon in the different fields: total number of phrases; number of unique phrases; content of factors from factor analyses; content of clusters from multi-link clustering. The Abstract field contains almost an order of magnitude more phrases than the other fields, and slightly more than an order of magnitude more unique phrases than the other fields. Each field used a factor matrix with 14 factors, and the combination of all 56 factors for the four fields represented 27 separate, but not unique, themes. These themes could be placed in two major categories, with two sub-categories per major category: Auto-immunity (antibodies, inflammation) and circulation (peripheral vessel circulation, coronary vessel circulation). All four sub-categories included representation from each field. Thus, while the focus of the representation of each field in each sub-category was moderately different, the four sub-category structure could be identified by analyzing the total factors in each field. In the cluster comparison phase of the study, the phrases used to create the clusters were the most important phrases identified for each factor. Thus, the factor matrix served as a filter for words used for clustering. While clusters were generated for all four fields, the Title hierarchy tended to be fragmented due to sparsity of the co-occurrence matrix that underlies the clusters. Therefore, the Title clusters were examined at only the lower levels of aggregation. The Abstract, Mesh, and Mesh + Title fields had the same first level taxonomy categories, auto-immunity and circulation. At the second level, the Abstract, Mesh, and Mesh + Title fields had the autoimmune diseases and antibodies sub-category in common. The Abstract and Mesh fields shared fascia inflammation as the other auto-immunity sub-category, while the other Mesh + Title sub-category focuses on vinyl chloride poisoning from industrial contact, and consequences of antineoplastic agents. However, in both cases, even though the words may be different, inflammation may be the common theme. CONCLUSIONS: For taxonomy generation, especially at the higher levels, each of the four fields has a similar thematic structure. At very detailed levels, the Mesh and Title fields run out of phrases relative to the Abstract field. Therefore, selection of field (s) to be employed for taxonomy generation depends on the objectives of the study, particularly the level of categorization required for the taxonomy. For information retrieval, or literature-based discovery, selection of the appropriate field again depends on the study objectives. If large queries, or large numbers of concepts or themes are desired, then the field with the largest number of technical phrases would be desirable. If queries or concepts represented by the more accepted popular terminology is adequate, then the smaller fields may be sufficient. Because of its established and controlled vocabulary, the Mesh field lags the Title or Abss the Title or Abstract fields in currency. Thus, the Title or Abstract fields would retrieve records with the most explicitly stated current concepts, but the Mesh field would capture a larger swath of fields that contained a concept of interest but perhaps had a wider range of specific terminology in the Abstract or Title text. In addition, this study provides the first validated estimate of the disparity in information retrieved through text mining limited to Titles and Mesh terms relative to entire Abstracts. As much of the older biomedical literature was entered into electronic databases without associated Abstracts, literature-based discovery exercises that search the older medical literature may miss a substantial proportion of relevant information. On the basis of this study, it may be estimated that up to a log order more information may be retrieved when complete Abstracts are searched.

Abstracting and Indexing↗
PubMed2004

Hypoxia induces HIF-1alpha and VEGF expression in chondrosarcoma cells and chondrocytes.

Like other tumors, chondrosarcoma must induce neovascularity as they grow. Recent studies have demonstrated that chondrosarcoma are vascular. Since normal cartilage is a hypoxic, yet avascular tissue and since chondrosarcoma bears some phenotypic relation to cartilage, it is not clear if hypoxic pathways remain intact in these tissues. Hypoxia-inducible factor 1alpha (HIF-1alpha) is the inducible subunit of the HIF-1 transcription factor that regulates genes involved in the response to hypoxia, some of which promote neovascularity. Vascular endothelial growth factor (VEGF) is one of the genes upregulated by HIF-1 and is the primary cytokine related to angiogenesis. In this study we examined the response of chondrocytes and chondrosarcoma cell lines to hypoxia. We found that both normal and malignant chondrocytes increased HIF-1alpha protein expression in an oxygen concentration dependent manner and also increased VEGF mRNA expression in response to hypoxia. HIF-1alpha protein and VEGF mRNA decreased when chondrosarcoma cells were transfected with siRNA targeting HIF-1alpha prior to hypoxia exposure, suggesting that HIF-1alpha expression resulted in increased VEGF expression. The role of the HIF-1alpha/VEGF pathway in angiogenesis in chondrosarcoma in vivo and its usefulness as a target for antiangiogenic treatment strategies for this tumor requires further investigation.

Bone Neoplasms↗
PubMed2003

Lack of efficacy of acetaminophen in treating symptomatic knee osteoarthritis: a randomized, double-blind, placebo-controlled comparison trial with diclofenac sodium.

BACKGROUND: Recommendations state that acetaminophen should be used in preference to nonsteroidal anti-inflammatory drugs in the initial treatment of symptomatic osteoarthritis (OA) of the hip or knee, because of lesser toxicity and the pervasive belief that acetaminophen is not only effective in treating OA pain but is of equal analgesic efficacy as nonsteroidal anti-inflammatory drugs. METHODS: This was a randomized, double-blind, placebo-controlled trial of diclofenac sodium, 75 mg twice daily, vs acetaminophen, 1000 mg 4 times daily, in 82 subjects with symptomatic OA of the medial knee. Osteoarthritis was quantitated radiographically, and subjects met stringent baseline pain criteria. The primary evaluation of efficacy used the Western Ontario and McMaster Universities Osteoarthritis Index, with evaluations at screening, baseline, and 2 and 12 weeks after treatment. Intention-to-treat analysis was used. RESULTS: Twenty-five subjects were randomized to diclofenac, 29 to acetaminophen, and 28 to placebo. The groups were closely matched for age, sex, body mass index, prior use of OA medications, baseline pain, and radiographic features. At 2 and 12 weeks, clinically and statistically significant (P<.001) improvements were seen in the diclofenac-treated group; however, no significant improvements were seen in the acetaminophen-treated group (P =.92 at 2 weeks and.19 at 12 weeks). Stratification of subjects according to baseline pain, prestudy OA medication, and radiographic grade showed no clear pattern of preferential response to diclofenac, and did not reveal a subset of subjects who responded to acetaminophen. CONCLUSIONS: Diclofenac is effective in the symptomatic treatment of OA of the knee, but acetaminophen is not. A review of the literature reveals that there is scanty published evidence for a therapeutic effect of acetaminophen relative to placebo in patients with OA of the knee, because most published studies use active comparators (ie, nonsteroidal anti-inflammatory drugs) only. The advocacy of acetaminophen use in subjects with OA of the knee should be reconsidered pending further placebo-controlled studies.

Acetaminophen↗
PubMed2003

Asymmetric knee loading in advanced unilateral hip osteoarthritis.

OBJECTIVE: Subjects with unilateral end-stage hip osteoarthritis (OA) who undergo total hip replacement (THR) preferentially require subsequent replacement of the contralateral knee compared with the ipsilateral knee. We investigated whether this nonrandom, preferential evolution of lower extremity OA from the hip to the contralateral knee joint may be related to asymmetries in dynamic joint loading at the knees, particularly the peak external knee adduction moment, which has been associated with the progression of knee OA. METHODS: Gait analysis was performed on 50 subjects who were preoperative for unilateral THR. Twenty-two of these subjects were reevaluated postoperatively 10-23 months after undergoing successful THR. At each analysis, dynamic joint loads in the contralateral knee were compared with those in the ipsilateral knee. RESULTS: Prior to THR, the peak external knee adduction moment and peak medial compartment load were significantly higher in the contralateral knee. This asymmetry persisted after THR. CONCLUSION: Subjects with unilateral end-stage hip OA preferentially require subsequent replacement of the contralateral knee, as compared with the ipsilateral knee. Among patients with unilateral end-stage hip OA, the contralateral knee is subjected to higher dynamic joint loads than is the ipsilateral knee, and this asymmetric loading persists long after subjects have undergone successful THR. Biomechanical factors appear to be involved in the multiarticular evolution of OA of the lower extremities.

Adult↗
PubMed2003

Inhibition of MMP-1 expression by antisense RNA decreases invasiveness of human chondrosarcoma.

We previously reported that an elevated level of matrix metalloproteinase-1 (MMP-1) gene expression in patients with chondrosarcoma has a strong statistical correlation with recurrence and in vitro invasion. In the present study, we used an antisense RNA strategy for MMP-1 inhibition to determine if this would affect the invasive characteristics of the cells. We transfected a human chondrosarcoma cell line with a retroviral plasmid expressing a 770 bp genomic fragment of the human MMP-1 gene in the sense or antisense orientation. The results show that cells transfected with the MMP-1 antisense fragment had a significant decrease in both MMP-1 protein and enzyme activity (p<0.05) as compared to cells transfected with an empty plasmid or the parental cells. Cells transfected with the MMP-1 antisense fragment demonstrated a significant decrease in their ability to invade the collagen I barrier (p<0.05). The gene expression for MMP-8 and MMP-13 were unaffected in cells transfected with the MMP-1 antisense fragment, MMP-1 sense fragment, or empty plasmid. These results support the hypothesis that MMP-1 facilitates tumor cell egress from chondrosarcoma tissue and demonstrate the potential of MMP-1 as a promising target for a novel biologic therapy in chondrosarcoma.

Cell Movement↗
PubMed2003

The C-terminal domain of focal adhesion kinase reduces the tumor cell invasiveness in chondrosarcoma cell lines.

Human chondrosarcoma is a malignancy that has no effective systemic therapy, making the interruption of the metastatic cascade critical to enhance patient survival. The processes of local invasion and metastases share similar mechanisms at a cellular level. Focal adhesion kinase (FAK) has been implicated in local invasion of malignant tumor cells. In the current manuscript we examine the effect of FAK inhibition on cell attachment to extracellular matrix (ECM) and in vitro invasion. Bovine articular chondrocytes and two human chondrosarcoma cell lines were utilized to examine FAK activity in tumor cell invasiveness. Endogenous FAK activity was inhibited by adenoviral transfection with the C-terminal domain of FAK. This inhibition resulted from decreased FAK phosphorylation, while FAK expression remained unchanged. Inhibition of FAK phosphorylation and hence its activity lead to decreased cell adhesion to Type II collagen and decreased cell invasiveness. These effects were not due to changes in integrin expression, indicating that the inhibition was the result of disruption of outside: in signaling. There are three important aspects to these results. The first is that interruption of transmembrane signaling can affect cell attachment. The second is that in chondrosarcoma, cell differentiation correlates with FAK expression and metastatic potential. Thirdly, that cell invasiveness correlates with FAK activity and implies a mechanistic role for this molecular complex in local invasion and metastasis.

Animals↗
PubMed2003

The frequency of thrombotic thrombocytopenic purpura in patients with systemic lupus erythematosus undergoing kidney biopsy.

OBJECTIVE: To characterize the frequency of thrombotic thrombocytopenic purpura (TTP) among patients with systemic lupus erythematosus (SLE) undergoing kidney biopsy. METHODS: A retrospective review of all renal biopsies of patients with SLE at Rush-Presbyterian-St. Luke's Medical Center was performed for the years 1989 to 2001. RESULTS: Four cases of clinical and histopathological TTP were identified among the 257 patients with SLE who underwent renal biopsy during the 12 year study period. CONCLUSION: TTP appears to occur at higher than expected frequency among SLE patients undergoing biopsy for unexplained renal failure.

Adult↗