The myth of Thomas Szasz.
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Attitude of Health Personnel↗
Biomedical subjects
Jeffrey Oliver
Publications and source records attributed to Jeffrey Oliver.
An in vivo evaluation of docetaxel delivered intratumorally in head and neck squamous cell carcinoma.
OBJECTIVE: To identify activity and biological mechanisms of intratumoral (IT) docetaxel on head and neck squamous cell carcinoma (HNSCC). METHODS: Docetaxel IT therapy was tested in xenograft models of 2 HNSCC lines, HN30 and HN12. The overall and disease-free survival rates, tumor growth, and toxic effects were measured. The pharmacokinetic profiles of docetaxel in plasma and tumor were compared after IT and intravenous (IV) administration. Comparisons between common and supradoses of docetaxel with regard to expression of regulators in the cell cycle, apoptosis, and signal transduction pathways were determined using Western blot analysis. RESULTS: In the HN30 and HN12 xenograft models, IT docetaxel improved overall as well as disease-free survival and reversed tumor growth. The only toxic effects noted were local (alopecia and skin breakdown). Skin breakdown resolved in all cases. At equivalent dosing levels, IT docetaxel achieved a 26-fold higher peak tumor concentration and 24-fold longer tumor exposure than IV treatment. Furthermore, limited plasma exposure was noted with IT docetaxel. Supradose levels of docetaxel produced distinct protein expression patterns for regulators of the cell cycle (cyclins A and B, p21, and p27), apoptosis (cleaved caspase-3 and cleaved PARP), and signal transduction (EGFR, pEGFR, pc-Jun, and pERK) in HNSCC, which supports a distinctive mechanism of action for supradose docetaxel levels. Since levels of cleaved caspase-3 and PARP, markers of apoptosis, were only elevated with lower doses, the observed cell death at supradose levels was probably due to necrosis. CONCLUSIONS: Injections of IT docetaxel at usual and supradoses are associated with a pharmacokinetic profile and biological mechanism distinct from those observed with usual IV doses. It is calculated that IT therapy in men will increase peak concentrations of docetaxel in tumors by 1000-fold over the conventional IV dose used clinically. These preclinical results support further testing of IT docetaxel in HNSCC.
Animals↗
Enhancement of T cell localization in mammary tumors through transient inhibition of T cell myosin function.
Adoptive immunotherapy is hampered by poor lymphocyte localization in tumors. The polarized, adhesive phenotype of activated lymphocytes may contribute to this problem by making the cells prone to trapping and damage in pulmonary microvasculature. We found that transient inhibition of T cell polarization prior to i.v. infusion reduces trapping and improves tumor localization. Activated T cells were rendered nonpolar and nonadhesive by treatment with myosin light-chain kinase inhibitor ML-7. Polarity, adhesiveness, and motility recovered by 6 h after treatment, cytotoxicity, and proliferation by 24 h. ErbB2-specific T cells were infused i.v. into mice bearing ErbB2-expressing mammary tumors. ML-7 pre-treatment reduced T cell arrest in lungs by a factor of eight, improved tumor localization by 4-fold, and increased lymph node homing. Although this improvement alone proved insufficient to alter outcome in an immunotherapy experiment, this study indicates that cytoskeletal modification is a promising strategy for altering the trafficking of infused lymphocytes.
Animals↗
Syndecan 1 shedding contributes to Pseudomonas aeruginosa sepsis.
The innate immune system is comprised of many components that function coordinately to prevent bacterial sepsis. However, thermal injury suppresses many of these factors, and the opportunistic pathogen Pseudomonas aeruginosa takes advantage of this condition, making it one of the leading causes of morbidity and mortality in the setting of thermal injury. P. aeruginosa is extremely efficient at colonizing burn wounds, spreading systemically, and causing sepsis, which often results in a systemic inflammatory response, multiple-organ failure, and death. The pathogenicity of P. aeruginosa is due to the arsenal of virulence factors produced by the pathogen and the immunocompromised state of the host. Syndecan 1 is a major heparan sulfate proteoglycan present on many host cells involved in thermal injury. Syndecan 1 anchored to the cell surface can be cleaved in a process termed ectodomain shedding. Syndecan 1 shedding results in the release of intact, soluble proteoglycan ectodomains that have diverse roles in innate immunity. Here we show for the first time that thermal injury results in shedding of syndecan 1 from host tissue. Our data show that syndecan 1 null mice are significantly less susceptible to P. aeruginosa infection than their wild-type counterparts, as demonstrated by (i) significantly lower mortality; (ii) absence of systemic spread of P. aeruginosa; and (iii) significant reductions in some proinflammatory cytokines. These results suggest that shed syndecan 1 plays an important role in the pathogenesis of P. aeruginosa infection of thermal injury and that syndecan 1-neutralizing agents may be effective supplements to current P. aeruginosa treatments.
Animals↗
The effects of exogenous p53 overexpression on HPV-immortalized and carcinogen transformed oral keratinocytes.
BACKGROUND: Overexpression of p53 in head and neck carcinoma cells has demonstrated tumor growth suppression using in vitro and in vivo models. The effects of exogenous overexpression of wild-type p53 on human papilloma virus (HPV)-immortalized and carcinogen transformed oral keratinocytes were determined. METHODS: The p53 gene was overexpressed in IHGK (immortalized human gingival keratinocyte), IHGKN [4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, (NNK)]-carcinogen transformed keratinocytes, and two head and neck squamous carcinoma (HNSCC) cell lines, HN30 and HN12. The transfection efficiency, growth suppression, and inhibition of the cell cycle along with the induction of apoptosis were measured. RESULTS: Transfections with adenoviruses were more efficient for IHGK cells than for IHGKN, HN12, and HN30 cells. Inhibition of proliferation in all cell lines was proportional to the viral particle to cell (VPC) ratios. IHGK cells were more sensitive to p53 than IHGKN cells. HN12 cells were more suppressed than HN30 cells. HN12 were the most suppressed at 72 hours whereas HN30 cells were most suppressed at 24 hours. Expression of exogenous p53-induced G1 cell cycle arrest and p21 expression as VPC ratios increased in IHGK and IHGKN cell lines. Apoptosis also was induced in these cells by p53 as VPC increased. IHGK cells were more sensitive to p53-induced growth inhibition, cell cycle regulation, p21 expression and apoptosis than IHGKN cells. HN12 (mutated p53) cells were more sensitive to p53 overexpression than HN30 (wild-type p53) cells. Gene transfer and expression of exogenous p53 by using Ad-p53 demonstrates suppressive effects on HPV immortalized and carcinogen transformed oral keratinocytes. CONCLUSIONS: Cell cycle regulation by gene transfer is feasible in immortalized oral keratinocytes. Carcinogen transformed cells are less susceptible to the effects of p53 overexpression. Expression of exogenous p53 through p53 gene transfer can suppress HPV immortalization and carcinogen transformation in oral keratinocytes. The sensitivity of HNSCC cell lines to p53-induced cell cycle regulation and apoptosis is variable and dependent on the cell line and duration of exposure. In vitro results using p53 gene transfer must be validated in clinical studies with patients at risk for HNSCC.
Adenoviridae↗
Silent reading rate and memory span.
This paper reports two experiments concerned with the form of the linear function relating memory span to pronunciation rate. Experiment 1 asked whether the intercept of the equation is attributable to an interaction between modality, word-length, and serial position. The results lead us to reject this possibility. Experiment 2 examined the shape of the span function for visual presentation of lists read aloud or silently. The results show that the intercept of the span function disappears for silent presentation but not for aloud presentation. The results are discussed in terms of a balance between two opposing effects of word-length.
Acoustic Stimulation↗