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Biomedical subjects

Laura Smith

Publications and source records attributed to Laura Smith.

15 recordsLinked to original sources
PubMed2006

Cancer proteomics and its application to discovery of therapy response markers in human cancer.

The administration of chemotherapy either alone or in combination with radiotherapy is an important factor in reducing the mortality and morbidity of cancer patients. Resistance to both chemotherapy and radiotherapy represents a major obstacle to a successful outcome. The identification of novel biomarkers that can be used to predict treatment response would allow therapy to be tailored on an individual patient basis. Although the mechanisms are unclear, it is accepted that development of therapy resistance is a multifactorial phenomenon involving alterations in several cellular pathways. Proteome analysis methods are powerful tools for identifying factors associated with resistance to anticancer therapy because they facilitate the simultaneous analysis of whole proteomes. The current review describes the plethora of existing proteomic approaches and details the studies that have identified biomarkers that may be useful in the prediction of clinical response to anticancer therapy.

Biomarkers, Tumor↗
PubMed2006

Elemental mapping and quantitative analysis of Cu, Zn, and Fe in rat brain sections by laser ablation ICP-MS.

This report details the application of laser ablation quadrupole ICP-MS for the (multi)elemental mapping of 100-microm-thick sections of rat brain. The laser spot size used was 60 microm, and the laser scan speed was 120 microm s(-1). The analysis was relatively rapid, allowing mapping of a whole brain thin section (approximately 1 cm2) in about 2 h. Furthermore, the method was amenable to multi-element data collection including the physiologically important elements P and S and afforded sub microg g(-1) detection limits for the important trace elements Cu and Zn. Calibrations were performed with pressed pellets of biological certified reference materials, and the elemental distributions and concentrations of Cu, Zn, and Fe were determined in whole rat brain sections. The distributions and concentration ranges for these elements were consistent with previous studies and demonstrate the utility of this technique for rapid mapping of brain thin sections.

Animals↗
PubMed2006

The analysis of doxorubicin resistance in human breast cancer cells using antibody microarrays.

Doxorubicin is considered to be the most effective agent in the treatment of breast cancer patients. Unfortunately, resistance to this agent is common, representing a major obstacle to successful treatment. The identification of novel biomarkers that are able to predict treatment response may allow therapy to be tailored to individual patients. Antibody microarrays provide a powerful new technique, enabling the global comparative analysis of many proteins simultaneously. This technology may identify a panel of proteins to discriminate between drug-resistant and drug-sensitive samples. The Panorama Cell Signaling Antibody Microarray was exploited to analyze the MDA-MB-231 breast cancer cell line and a novel derivative, which displays significant resistance to doxorubicin at clinically relevant concentrations. The microarray comprised 224 antibodies selected from a variety of pathways, including apoptotic and cell signaling pathways. A standard >/=2.0-fold cutoff value was used to determine differentially expressed proteins. A decrease in the expression of mitogen-activated protein kinase-activated monophosphotyrosine (phosphorylated extracellular signal-regulated kinase; 2.8-fold decrease), cyclin D2 (2.5-fold decrease), cytokeratin 18 (2.5-fold decrease), cyclin B1 (2.4-fold decrease), and heterogeneous nuclear ribonucleoprotein m3-m4 (2.0-fold decrease) was associated with doxorubicin resistance. Western blotting was exploited to confirm results from the antibody microarray experiment. These results suggest that antibody microarrays can be used to identify novel biomarkers and further validation may reveal mechanisms of chemotherapy resistance and identify potential therapeutic targets. [Mol Cancer Ther 2006;5(8):2115-20].

Antibiotics, Antineoplastic↗
PubMed2006

Immunohistochemical detection of apoptotic markers in gastric cancer.

Apoptosis proteins may play a role in prognosis and therapy response; however, they have not been fully investigated in gastric cancer. We aimed to assess the expression of proteins in the Bcl-2 family. Immunohistochemistry was employed to examine the expression of the antiapoptotic proteins Bcl-2 and Bcl-XL and the proapoptotic proteins Bad, Bak, Bax, Bid, Bim, and p53 in 21 cases of gastric cancer. Immunopositivity was observed in 12/21 (57%) cases for p53, 16/21 (76%) cases for Bcl-XL, and 5/21 (23%) cases for Bcl-2. For the proapoptotic members of the Bcl family, loss of protein expression was observed: Bid (14/21 cases; 66%), Bad (13/21 cases; 61%), Bax (12/21 cases; 57%), Bak (9/21 cases; 42%), and Bim (4/21 cases; 19%). This study identified apoptosis proteins that exhibit heterogeneous expression between primary gastric carcinomas.

Aged↗
PubMed2006

Hsp27 may allow prediction of the response to single-agent vinorelbine chemotherapy in non-small cell lung cancer.

One of the most valuable objectives for oncologists is the ability to predict patient response to chemotherapy before drugs are administered in order to maximise the therapeutic benefit of treatment whilst limiting the toxicity. This is particularly relevant in non-small cell lung cancer as the initial treatment decision is important due to the inherent drug resistance of many tumours and short survival times of patients. We established a homogeneous series of pre-treatment archival biopsy samples from patients receiving first-line single-agent vinorelbine for non-small cell lung cancer. Cases were selected following strict inclusion criteria and patient response was assessed using the Response Evaluation Criteria in Solid Tumours guideline. The expression of 7 proteins was investigated and correlated with response data. Chi-square analysis revealed no association between expression of Bcl-2, Bcl-XL, Bad, Bak, Bid or p53 proteins and response to vinorelbine therapy. There was a trend for Hsp27-positive tumours to show progression but this did not reach significance (p=0.068). The results suggest that Hsp27 expression may be useful as a predictor of response to single-agent vinorelbine chemotherapy in non-small cell lung cancer patients but a larger study is required to confirm this.

Aged↗
PubMed2005

Solution and solid-state variation of cupric phenanthroline complexes.

The 1:1 cupric-phenanthroline complexes, [Cu(5,6-Me2-phen)(MeCN)2(BF4)](BF4) (1), [Cu(o-phen)(MeCN)2(H2O)](BF4)2 (2), and [Cu(5-Cl-phen)(MeCN)2(BF4)](BF4) (3), have been prepared and characterized by X-ray crystallography. The structures of 1 and 3 are characterized by an equatorial plane about the copper center consisting of a phenanthroline ligand and two acetonitrile ligands. The copper units are connected by bridging counterions in the axial positions of the pseudo-octahedral metal centers to form one-dimensional solid-state linkages. The structure of 2 contains the same equatorial plane as 1 and 3, but an axial water ligand completes a square pyramidal geometry for each discrete metal unit. Although the solid-state structures vary for the three complexes, characterization through electronic spectroscopy and cyclic voltammetry reveals similar behavior for all three complexes in solution.

Journal Article↗
PubMed2005

The expression of Bcl-2 family proteins differs between nonsmall cell lung carcinoma subtypes.

BACKGROUND: Proteins of the Bcl-2 family play a key role in the control of apoptosis and carry out both proapoptotic and antiapoptotic functions. However, with the exception of Bcl-2 itself, little is known about the expression of these potentially critical proteins in nonsmall cell lung carcinoma. METHODS: Immunohistochemistry was used to study the expression of Bcl-2 and 6 other Bcl-2 family proteins in a pilot series of 41 archival nonsmall cell lung carcinoma specimens (19 adenocarcinomas and 22 squamous cell carcinomas). RESULTS: Overexpression of the apoptosis inhibitors Bcl-2 and Bcl-X(L) was observed in 10 of 41 samples (24%) and in 11 of 41 samples (27%), respectively. Loss of expression of proapoptotic proteins was observed as follows: Bak, 24 of 41 samples (59%); Bad, 21 of 41 samples (51%); Bid, 20 of 41 samples (49%); Bax, 14 of 41 samples (34%); and Bim/Bod, 2 of 41 samples (5%). Statistically significant differences in expression between adenocarcinoma samples and squamous cell carcinoma samples were observed for Bcl-X(L) (overexpression in 11 of 19 adenocarcinomas [58%] vs. 0 of 22 squamous cell carcinomas [0%]; P < 0.001) and for Bad (loss of expression in 5 of 19 adenocarcinomas [26%] vs. 16 of 22 squamous cell carcinomas [73%]; P = 0.004). CONCLUSIONS: Although this was only a pilot study, the results revealed significant differences in the expression of apoptosis-related proteins both between individual samples of nonsmall cell lung carcinoma and between the two main histologic subtypes. Such differences may play a role in the development of lung tumors; and, if it is found that these differences are of clinical importance, then it may be required to regard nonsmall cell lung carcinoma subtypes as separate entities rather than as one disease.

Adenocarcinoma↗
PubMed2005

Examining the association between pediatric bipolar disorder and anxiety disorders in psychiatrically referred children and adolescents.

BACKGROUND: To examine the association between anxiety (ANX) and bipolar disorders (BPD) in a clinically referred pediatric sample. METHODS: Subjects were consecutively referred youth aged <18 years, with a DSM-III-R/DSM-IV diagnosis of BPD (n=297) or a disruptive behavior disorder (DBD) (n=1100) on structured interview. RESULTS: Bipolar disorder in youth was associated with a significantly increased risk for most of the DSM-IV anxiety disorders and was not specifically linked to any one disorder in particular. CONCLUSIONS: Bipolar disorder in youth is a significant risk factor for anxiety comorbidity. Considering the morbidity and dysfunction as well as the differing therapeutic needs associated with bipolar and anxiety symptomatology, appropriate therapeutic approaches will be needed for the management of youth with this comorbidity.

Adolescent↗
PubMed2005

Psychotherapy, classism, and the poor: conspicuous by their absence.

Four decades of research have delineated the need for improved psychotherapeutic opportunities for poor clients, yet psychotherapists remain contradictory in their stance regarding service to the poor. Despite periodic calls within the field to address the needs of poor people, evidence from the psychotherapeutic literature suggests that the poor are still largely absent from consideration. What barriers prevent psychotherapists from enacting their professional principles more consistently on behalf of poor clients? The author suggests that unexamined classist assumptions constitute a significant obstacle for practitioners and presents the experience of confronting her own classism to illustrate the operation of these attitudinal barriers.

Health Services Accessibility↗
PubMed2005

How might the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 affect the financial viability of rural pharmacies? An analysis of preimplementation prescription volume and payment sources in rural and urban areas.

CONTEXT: Passage of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) has created interest in how the legislation will affect access to prescription drugs among rural beneficiaries. Policy attention has focused to a much lesser degree on the implications of the MMA for the financial viability of rural pharmacies. PURPOSE: This article presents descriptive information on mail-order prescriptions, volume, and payer type of retail prescriptions in rural vs urban areas. Together, these data provide a baseline for evaluating how implementation of the MMA may affect the financial viability of rural independent pharmacies. METHODS: Projections of prescriptions dispensed from retail and mail-order pharmacies in 2002 for the total US and a sample of 17 states were obtained from IMS Health. FINDINGS: The volume of mail-order prescriptions is small. Rural providers prescribed fewer retail and mail-order prescriptions per person, but more units per person. Rural areas have a higher percentage of prescriptions paid for by cash (18% vs 13%) and Medicaid (16% vs 10%) and a lower percentage of third-party payers than urban areas. Significant variation in volume and payer type exists between states. CONCLUSIONS: Rural, independent pharmacies may be negatively affected by MMA implementation as business shifts from cash to third-party reimbursement. The high degree of variation between states also has potentially important implications for the implementation of Prescription Drug Plan regions under MMA.

Community Pharmacy Services↗
PubMed2005

Inhibition of the epidermal growth factor receptor increases expression of genes that stimulate inflammation, apoptosis, and cell attachment.

The epidermal growth factor receptor (EGFR) is overexpressed in several types of human cancer, and inhibition of EGFR function is a promising strategy for cancer therapy. We used cDNA microarrays to examine alterations in gene expression after treatment of carcinoma cells with PD153035, a specific and reversible inhibitor of EGFR function. When human cervical carcinoma cells were grown on a collagen substrate in three-dimensional organotypic culture, untreated cells expressed high levels of EGFR RNA and invaded the underlying collagen. Blocking EGFR function decreased DNA synthesis and inhibited invasion in a dose-dependent manner. Microarray analyses identified 312 genes that were significantly increased or decreased in expression after EGFR inhibition. Many could be classified into one of four functional groups including genes that (a) stimulate inflammation and innate immunity, (b) promote cell attachment, (c) enhance apoptosis, and (d) inhibit cell cycle progression. PD153035 induced a dose-dependent activation of nuclear factor kappaB, a transcription factor that stimulates proinflammatory gene expression. Our results identify alterations in gene expression caused by EGFR inhibition and show that this response varies significantly in different cell lines.

Antineoplastic Agents↗
PubMed2004

Strain-dependent differences in malignant conversion of mouse skin tumors is an inherent property of the epidermal keratinocyte.

The multistage evolution of squamous skin tumors induced by chemical or viral carcinogens on mice from different genetic backgrounds has been a valuable model to define low penetrance loci that determine cancer susceptibility or resistance. Susceptibility determinants are multigenic, stage-specific, dependent on the carcinogenesis protocol, and in the case of initiating events, intrinsic properties of keratinocytes. In this study we examined the malignant conversion frequency of keratinocytes derived from FVB/N, inbred SENCARA/Pt, BALB/c or C57BL/6 mouse strains that differ substantially in the frequency of progression from papilloma to carcinoma. Keratinocytes were cultured from newborn mice and tested in an in vitro malignant conversion assay induced by a chemical carcinogen or immortalized by infection with replication defective human papillomavirus type 16 (HPV-16) E6/E7 retroviruses and tested for malignancy by grafting immortalized cell lines to nude mice. In vitro, FVB/N keratinocytes were 10-fold more sensitive to chemically induced malignant conversion than keratinocytes from other strains, consistent with the known sensitivity of this strain to pre-malignant progression in vivo. The E6/E7 genes induced immortalization of keratinocytes from FVB/N, SENCARA/Pt or C57BL/6 mice more efficiently than BALB/c, and HPV-16-immortalized FVB/N keratinocytes formed tumors more frequently (64%) than SENCARA/Pt (31%) BALB/c (1.9%) or C57BL/6 (2.5%). Furthermore, 78% of the tumors formed by FVB/N keratinocytes progressed to squamous carcinomas compared with 46% for SENCARA/Pt-derived cells and <3% for the others. In F(1) offspring of crosses from SENCARA/Pt and FVB/N mice, both the papilloma incidence and frequency of malignant conversion reflected the SENCARA/Pt parent indicating that predisposition to pre-malignant progression is not a dominant characteristic. This predisposition is an intrinsic property of the target keratinocytes and as such should be amenable to further study in isolated cells.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2002

Scale-up and optimization of an acoustic filter for 200 L/day perfusion of a CHO cell culture.

Acoustic cell retention devices have provided a practical alternative for up to 50 L/day perfusion cultures but further scale-up has been limited. A novel temperature-controlled and larger-scale acoustic separator was evaluated at up to 400 L/day for a 10(7) CHO cell/mL perfusion culture using a 100-L bioreactor that produced up to 34 g/day recombinant protein. The increased active volume of this scaled-up separator was divided into four parallel compartments for improved fluid dynamics. Operational settings of the acoustic separator were optimized and the limits of robust operations explored. The performance was not influenced over wide ranges of duty cycle stop and run times. The maximum performance of 96% separation efficiency at 200 L/day was obtained by setting the separator temperature to 35.1 degrees C, the recirculation rate to three times the harvest rate, and the power to 90 W. While there was no detectable effect on culture viability, viable cells were selectively retained, especially at 50 L/day, where there was a 5-fold higher nonviable washout efficiency. Overall, the new temperature-controlled and scaled-up separator design performed reliably in a way similar to smaller-scale acoustic separators. These results provide strong support for the feasibility of much greater scale-up of acoustic separations.

Acoustics↗