Integrin expression and osteopontin regulation in human fetal osteoblastic cells mediated by substratum surface characteristics

Integrin-mediated adhesion of anchorage-dependent cells to scaffolds is a critical component of tissue engineering. We investigated integrin expression by the human fetal osteoblastic cell line, hFOB 1.19 (hFOB), as a function of substratum surface wettability. The influence of surface wettability on bone cell phenotype was also examined. Plasma-treated quartz (PTQ) and glass (PTG) (hydrophilic, contact angles of 0 degrees), octadecyltrichlorosilane-treated quartz (STQ) and glass (STG) (hydrophobic, contact angles above about 100 degrees), and tissue culture polystyrene were used for cell culture. hFOB cells cultured on hydrophilic substrata displayed well-developed actin stress fibers relative to cells on hydrophobic substrata. Western blot analysis revealed that hFOB cells cultured on hydrophobic substrata (STQ or STG) express lower levels of alphav and beta3 integrin subunits than do cells on hydrophilic substrata (PTQ or PTG). This effect was more pronounced in cells on STQ than on STG. These variations in integrin expression were lessened by extended culture time. Double- labeled integrin/actin immunofluorescence confirmed Western blot results, that is, cells cultured on PTQ displayed distinct, large plaques of alphav and beta3 subunits and integrin alphavbeta3, as well as their colocalization with actin stress fiber ends, whereas cells on STQ did not display integrin plaques after 24 h and displayed only minimal plaque formation after 3 days. Vinculin, a focal adhesion protein that mediates binding between the integrin and actin cytoskeleton, appeared in Western blots to mimic the variations of alphav and beta3 expression with respect to surface wettability. Interestingly, real-time RT-PCR analysis showed that hFOB cultured on hydrophobic substrata, which have downregulated alphav and beta3 integrin subunits, displayed greater steady state mRNA levels of osteopontin, an extracellular matrix (ECM) protein containing the Arg-Gly-Asp (RGD) integrin recognition sequence, than did cells cultured on hydrophilic substrata. Our results imply that substratum surface wettability regulates integrin-mediated bone cell adhesion and further influences the expression of bone cell-ECM complexes.     

Unusual cardiac papillary fibroelastoma in the right ventricular outflow tract.

Cardiac papillary fibroelastoma (CPF) is the second most common benign neoplasm of the heart. This study describes the case of an 81-year-old man who was admitted to the hospital for severe vertigo and in whom a tumor at the right ventricular outflow tract (RVOT) was identified incidentally during echocardiography. The CPF was excised smoothly following the confirmation of its position by computed tomography. The comprehensive pathologic findings of CPF were reviewed. Detailed immunohistochemical analyses of CD34 and factor VIII-related antigen were performed on the covering endocardial cells. The unique chondroid metaplasia of fibrous tissue in this CPF has never been reported. This work is the first to present an unusual CPF at the RVOT with reactive process of fibrous connective tissue.     

Clonal structural chromosome aberrations in fibrous dysplasia

Cytogenetic analysis of short-term cultures from a case of monostotic fibrous dysplasia in a 14-year-old girl revealed multiple clonal structural rearrangements with evidence of clonal evolution. The karyotype was 46,XX,del(3)(q27),add(10)(q22), add(12)(p13)/46,idem,t(3;8)(p21;q13),add(10)(q26),der(15)del(15)(q15q22)ins(15;?)(q15;?)/46,idem,-X, + 2,t(3;8),add(10),der(15). The finding of clonal structural aberrations suggests that fibrous dysplasia is a neoplastic lesion which develops as the result of somatic mutations.     

Chromosome analysis of 20 breast carcinomas: Cytogenetic multiclonality and karyotypic-pathologic correlations

Short-term cultures from 20 breast carcinomas were analyzed cytogenetically. A normal female chromosome complement was found in 4 cases. Clonal chromosome aberrations were detected in 16 tumors. In 10 tumors, multiple cytogenetic clones were found; in 2 cancers the clones were related, reflecting clonal evolution, but in the remaining 8 tumors the clones were cytogenetically unrelated, indicating clonal heterogeneity in the origin of the tumor parenchyma. Correlation analysis between karyotypic and pathologic parameters indicated that cases with complex karyotypes and/or cytogenetically unrelated clones, when compared with cases with a single simple karyotypic abnormality, were generally of higher histologic malignancy grade, had more mitoses in the histologic sections, and also more often had carcinoma in situ lesions in the same breast. © 1993 Wiley-Liss, Inc.     

Frequent rearrangement of chromosomal bands 1p22 and 11q13 in squamous cell carcinomas of the head and neck

We report the finding of clonal structural chromosome abnormalities in short-term cultures from 15 squamous cell carcinomas of the head and neck region. When the distribution of chromosomal breakpoints in these 15 tumors and in the 16 head and neck carcinomas previously described are assessed, a marked clustering is seen at bands 1p22 and 11q13, which are rearranged in eight and nine tumors, respectively. No other band was involved in aberrations in more than five tumors. Cytogenetic evidence of gene amplification was seen in four tumors, three times in the form of homogeneously staining regions (twice located in 11q13), and in one tumor as double minutes. Among the candidate genes for such amplification are BCLI, INT2, and HSTI, all of which map to 11q13, and NRAS, which maps to 1p22. All these oncogenes have previously been shown to be amplified in subsets of head and neck carcinomas. We conclude that bands 1p22 and 11q13 are nonrandomly involved in chromosomal rearrangements in head and neck carcinomas and suggest that activation of oncogenes located in these bands may proceed via cytogenetic mechanisms.     

Assessment of an undergraduate psychiatry course in an African setting

Background  

International reports recommend the improvement in the amount and quality of training for mental health workers in low and middle income countries. The Scotland-Malawi Mental Health Education Project (SMMHEP) has been established to support the teaching of psychiatry to medical students in the University of Malawi. While anecdotally supportive medical educational initiatives appear of value, little quantitative evidence exists to demonstrate whether such initiatives can deliver comparable educational standards. This study aimed to assess the effectiveness of an undergraduate psychiatry course given by UK psychiatrists in Malawi by studying University of Malawi and Edinburgh University medical students' performance on an MCQ examination paper.     

A Novel Mutation in the GATA1 Gene Associated with Acute Megakaryoblastic Leukemia in a Korean Down Syndrome Patient

Although acquired mutations in the GATA1 gene have been reported for Down syndrome-related acute megakaryoblastic leukemia (DS-AMKL) in Caucasians, this is the first report of a Korean Down syndrome patient with AMKL carrying a novel mutation of the GATA1 gene. A 3-yr-old Korean girl with Down syndrome was admitted to our hospital complaining of pallor and fever. The findings of a peripheral blood smear and bone marrow study were compatible with the presence of AMKL. A chromosome study showed 48,XX,-7,+21c,+21,+r[3]/47,XX,+21c[17]. Following GATA1 gene mutation analysis, a novel mutation, c.145dupG (p.Ala49GlyfsX18), was identified in the N-terminal activation domain of the GATA1 gene. This mutation caused a premature termination at codon 67 and expression of an abnormal GATA-1 protein with a defective N-terminal activation domain, and the absence of full-length GATA-1 protein. This case demonstrates that a leukemogenic mechanism for DS-AMKL is contributed by a unique collaboration between overexpressed genes from trisomy 21 and an acquired GATA1 mutation previously seen in Caucasians and now in a Korean patient.     

The effect of alphaMSH analogues on rat bones

Melanocortin is the downstream mediator of leptin signaling and absence of leptin signaling in ob/ob and db/db mice revealed the enhancement of bone formation through the central regulation. While alpha-melanocyte-stimulating hormone (alphaMSH) inhibits the secretion of interleukin-1alpha and tumor necrosis factor-alpha from the inflammatory cells, alphaMSH can also enhance clonal expansion of pro B cells linked to stimulation of osteoclastogenesis. Therefore, we tested the effect of melanocortin on bones. alphaMSH analogues [(6)His]alphaMSH-ND and [(6)Asn]alphaMSH-ND were synthesized and the radio-ligand receptor binding- and cyclic AMP generating activity were analyzed in China Hamster Ovary cell line over- expressing melanocortin receptors. The EC(50) of [(6)His]alphaMSH-ND measured from melanocortin-1, 3, 4 and 5 receptors were 0.008 +/- 0.0045, 1.523 +/- 0.707, 0.780 +/- 0.405, and 250.320 +/- 42.234 nM, respectively, and the EC(50) of [(6)Asn]alphaMSH-ND were 16.8 +/- 6.94, 271.8 +/- 21.95, 8.0 +/- 1.21, and 1132.5 +/- 635.46 nM, respectively. Four weeks after the subcutaneous injection of the analogues, the body weights in the [(6)His]alphaMSH-ND and the [(6)Asn]alphaMSH-ND treated groups (346.0 +/- 20.63 g vs. 350.0 +/- 13.57 g) were lower than that of the vehicle treated group (375.8 +/- 17.31 g, p < 0.05). There was no difference in the total femoral BMD measured by dual x-ray absorptiometry among the three groups. Among the three groups, there were no differences in the total numbers of crystal violet positive- or alkaline phosphatase positive colonies, in the expression of Receptor Activator of Nuclear Factor Kappa-B ligand on the tibia and the total number of multinucleated osteoclast-like cells differentiated from primary cultured bone marrow cells. From the above results, no evidence of bone gain or loss was found after treatment of the alphaMSH analogues peripherally.     

The value of immunohistochemical detection of P-glycoprotein in breast cancer before and after induction chemotherapy.

We have studied the patterns of P-glycoprotein expression before and after 3 cycles of induction chemotherapy (5-fluorouracil, adriamycin and cyclophosphamide) using immunohistochemically stained paraffin-embedded specimen of 28 patients with locally advanced breast cancer. The frequency of P-glycoprotein expression in untreated breast cancer turned out to be very low: only one out of 28 untreated, biopsy specimen at the time of diagnosis was positive. The frequency of P-glycoprotein expression was markedly increased from 9.1% before chemotherapy to 63.6% after induction chemotherapy (p = 0.006). After 3 cycles of induction chemotherapy, 25 patients had obtained clinical response to chemotherapy (4, CR; 21, PR). Eleven out of 25 tumors (44%) showing clinical response and all three tumors (100%) with minimal response have expressed P-glycoprotein. One out of 6 patients (16.7%) with microscopic residual tumor seen in mastectomy specimen expressed P-glycoprotein, whereas 13 of 22 patients (59.1%) with gross residual tumor showed the presence of P-glycoprotein (p = 0.08). The frequency of intrinsic P-glycoprotein expression in untreated breast cancer was quite low, but approximately half of the patients do acquire P-glycoprotein expression during the cycles of induction chemotherapy. Therefore, the results suggest that the immunohistochemical detection of P-glycoprotein on residual tumor cells after induction chemotherapy can predict acquired drug resistance in breast cancer.