Optimal frequency of Imiquimod (Aldara(RTM)) 5% cream treatment of external genital warts in immunocompetent adults. Systematic review and meta-analysis

Genital warts are a sexually transmitted disease with high prevalence in the U.S. Imiquimod 5% cream is a self-applied treatment, prescribed three-times weekly, at bedtime, for 16 weeks. The post-marketing research addressed questions of imiquimod dosing frequency. MEDLINE, Embase, and the Cochrane Library were searched for randomized trials on efficacy and safety of imiquimod 5% cream with either three-times weekly or once-daily regimens to systemically review treatment options. Efficacy was evaluated by completely cleared warts at the end of treatment, and safety - by frequency of adverse events and at least one rest period taken from treatment. Six studies were selected for the analysis, including circumcised men, uncircumcised men, and women. The once-daily compared to three-times weekly regimen did not improve the efficacy, but resulted in increased incidence of local skin reactions and events, when at least one rest period was taken from treatment. The optimal regimen is three-times weekly.^

Effects of Combined Bevacizumab and Paclitaxel on Tumor Interstitial Fluid Pressure in a Preclinical Breast Cancer Model

Effects of Combined Bevacizumab and Paclitaxel on Tumor Interstitial Fluid Pressure in a Preclinical Breast Cancer Model by Ricardo H. Alvarez Several mechanisms of cell resistance are often accountable for unsuccessful chemotherapy against cancer. Another reason, which has received increased attention, is the inefficient transport of anticancer drugs into tumor tissue. These impaired transports of chemotherapy into the tumor have been attributed to abnormal microvasculature and to pathologically increased tumor hypertension also called: interstitial fluid pressure (IFP). The pathophysiological processes leading to elevated tumor IFP are poorly understood. Here, in a preclinical breast cancer model, it is argued that a condition of raised IFP is a major factor in preventing optimal access of systemically administered chemotherapy agents. In our experimental model, we used a GILM2 human breast cancer in xenografts; mice were treated with different doses of paclitaxel –a widely used antimicrotubular agent, and bevacizumab –monoclonal antibody against vascular endothelial growth factor (VEGF). The proposed research project is designed to test the hypothesis that paclitaxel in combination with bevacizumab decreases the tumor IPF by restoring tumor permeability and increasing chemotherapy delivery. We demonstrated that the combination of paclitaxel and bevacizumab produced greater tumor control than either agent given alone and this combination reduced the IFP, producing an increment of 75% of apoptosis compared with the control arm. In addition, the intra-tumor paclitaxel quantification by liquid chromatography/Mass Spectrometry (LC/MS) demonstrated that lower dose of both agents showed a synergistic effect compared with high dose of treatment, where there is no significantly increase of paclitaxel into the tumor. These preclinical results are likely to have broad implications for the utility of anti-angiogenic therapies alone and in combination with chemotherapeutic agents.

Abnormal expression of REST/NRSF and Myc in neural stem/progenitor cells causes cerebellar tumors by blocking neuronal differentiation.

Medulloblastoma, one of the most malignant brain tumors in children, is thought to arise from undifferentiated neural stem/progenitor cells (NSCs) present in the external granule layer of the cerebellum. However, the mechanism of tumorigenesis remains unknown for the majority of medulloblastomas. In this study, we found that many human medulloblastomas express significantly elevated levels of both myc oncogenes, regulators of neural progenitor proliferation, and REST/NRSF, a transcriptional repressor of neuronal differentiation genes. Previous studies have shown that neither c-Myc nor REST/NRSF alone could cause tumor formation. To determine whether c-Myc and REST/NRSF act together to cause medulloblastomas, we used a previously established cell line derived from external granule layer stem cells transduced with activated c-myc (NSC-M). These immortalized NSCs were able to differentiate into neurons in vitro. In contrast, when the cells were engineered to express a doxycycline-regulated REST/NRSF transgene (NSC-M-R), they no longer underwent terminal neuronal differentiation in vitro. When injected into intracranial locations in mice, the NSC-M cells did not form tumors either in the cerebellum or in the cerebral cortex. In contrast, the NSC-M-R cells did produce tumors in the cerebellum, the site of human medulloblastoma formation, but not when injected into the cerebral cortex. Furthermore, the NSC-M-R tumors were blocked from terminal neuronal differentiation. In addition, countering REST/NRSF function blocked the tumorigenic potential of NSC-M-R cells. To our knowledge, this is the first study in which abnormal expression of a sequence-specific DNA-binding transcriptional repressor has been shown to contribute directly to brain tumor formation. Our findings indicate that abnormal expression of REST/NRSF and Myc in NSCs causes cerebellum-specific tumors by blocking neuronal differentiation and thus maintaining the "stemness" of these cells. Furthermore, these results suggest that such a mechanism plays a role in the formation of human medulloblastoma.

Surveillance of antimicrobial resistance of Streptococcus pneumoniae and Haemophilus influenzae in children with pneumonia

In order to identify optimal therapy for children with bacterial pneumonia, Pakistan's ARI Program, in collaboration with the National Institute of Health (NIH), Islamabad, undertook a national surveillance of antimicrobial resistance in S. pneumoniae and H. influenzae. The project was carried out at selected urban and peripheral sites in 6 different regions of Pakistan, in 1991–92. Nasopharyngeal (NP) specimens and blood cultures were obtained from children with pneumonia diagnosed in the outpatient clinic of participating facilities. Organisms were isolated by local hospital laboratories and sent to NIH for confirmation, serotyping and antimicrobial susceptibility testing. Following were the aims of the study (i) to determine the antimicrobial resistance patterns of S. pneumoniae and H. influenzae in children aged 2–59 months; (ii) to determine the ability of selected laboratories to identify and effectively transport isolates of S. pneumoniae and H. influenzae cultured from nasopharyngeal and blood specimens; (iii) to validate the comparability of resistance patterns for nasopharyngeal and blood isolates of S. pneumoniae and H. influenzae from children with pneumonia; and (iv) to examine the effect of drug resistance and laboratory error on the cost of effectively treating children with ARI. ^ A total of 1293 children with ARI were included in the study: 969 (75%) from urban areas and 324 (25%) from rural parts of the country. Of 1293, there were 786 (61%) male and 507 (39%) female children. The resistance rate of S. pneumoniae to various antibiotics among the urban children with ARI was: TMP/SMX (62%); chloramphenicol (23%); penicillin (5%); tetracycline (16%); and ampicillin/amoxicillin (0%). The rates of resistance of H. influenzae were higher than S. pneumoniae: TMP/SMX (85%); chloramphenicol (62%); penicillin (59%); ampicillin/amoxicillin (46%); and tetracycline (100%). There were similar rates of resistance to each antimicrobial agent among isolates from the rural children. ^ Of a total 614 specimens that were tested for antimicrobial susceptibility, 432 (70.4%) were resistant to TMP/SMX and 93 (15.2%) were resistant to antimicrobial agents other than TMP/SMX viz. ampicillin/amoxicillin, chloramphenicol, penicillin, and tetracycline. ^ The sensitivity and positive predictive value of peripheral laboratories for H. influenzae were 99% and 65%, respectively. Similarly, the sensitivity and positive predictive value of peripheral laboratory tests compared to gold standard i.e. NIH laboratory, for S. pneumoniae were 99% and 54%, respectively. ^ The sensitivity and positive predictive value of nasopharyngeal specimens compared to blood cultures (gold standard), isolated by the peripheral laboratories, for H. influenzae were 88% and 11%, and for S. pneumoniae 92% and 39%, respectively. (Abstract shortened by UMI.)^

Alteration of CEACAM1 gene transcription in prostate cancer cells: The role of AR, Sp2, and HDAC

Cell to cell adhesion molecule (CEACAM1), a type II tumor suppressor, has been found to be down-regulated in prostate cancer cells. The mechanism that causes CEACAM1's down-regulation in tumorigenesis is unknown. Here we show that the transcriptional activity of CEACAM1 is decreased in prostate cancer cells. This decrease is not due to methylation of the CEACAM1's promoter, but rather to the alteration of transcription factors regulating CEACAM1 expression. ^ Since androgen/androgen receptors (AR) are potent regulators of prostate growth and differentiation, their role on CEACAM1 gene transcription was examined. The androgen receptor could directly increase CEACAM1 transcriptional activity in a ligand dependent manner by interacting with an AR consensus element that resides in the CEACAM1 promoter. However, AR binding to the CEACAM1 promoter is not related to the loss of CEACAM1 during prostate cancer progression. ^ Further analysis enabled us to determine the particular region in the CEACAM1 promoter that mediates a decrease in CEACAM1 transcriptional activity in prostate cancer cells. Upon further examination, we found that this CEACAM1 promoter region interacts with the Sp1, Sp2, and Sp3 transcription factors. However, only Sp2 expression was found to increase in prostate cancer cells. Inhibiting Sp2 from binding to the CEACAM1 promoter caused an increase in CEACAM1 transcriptional activity in prostate cancer cells. In addition, over-expressing Sp2 in normal prostate cells resulted in a decrease in CEACAM1 transcriptional activity and endogenous protein expression. These observations suggest that Sp2 is a transcription repressor of CEACAM1. Furthermore, prostate cancer cells treated with trichostatin A (TSA), a specific histone deacetylase (HDAC) inhibitor, activated CEACAM1 transcriptional activity. This implies that HDACs are involved in CEACAM1 transcriptional activity. Mutation of the Sp2 DNA binding region on the CEACAM1 promoter inhibited TSA activation of CEACAM1 transcriptional activity. This indicates that HDACs inhibit CEACAM1 transcriptional activity through Sp2. Base on these results, we propose that Sp2 is critical for down-regulating CEACAM1 expression, and one mechanism by which Sp2 represses CEACAM1 expression is by recruiting HDAC to the CEACAM1 promoter in prostate cancer cells. Collectively, these findings provide novel insights into mechanisms that cause the down-regulation of CEACAM1 expression in prostate cancer cells. ^

Negotiated settlements: The utilities, multiple regulators and clean air

Utilities have made strides in reducing air pollutant levels, but the proposed 1990 Clean Air Act Amendments call for even greater reductions and more stringent enforcement. Federal and state air enforcement agencies now encourage the use of negotiated settlements as a way to bring about compliance. This research examines the operation of such procedures in 19 case studies and a formal survey with the negotiators to account for the differences in the nature of the settlements and to identify the factors contributing to their perceived success. ^

HEALTH MAINTENANCE ORGANIZATION ENVIRONMENT: AN EMPIRICAL STUDY OF THE RELATIONSHIP OF EXTERNAL CONTEXT AND PERFORMANCE

The research project is an extension of a series of administrative science and health care research projects evaluating the influence of external context, organizational strategy, and organizational structure upon organizational success or performance. The research will rely on the assumption that there is not one single best approach to the management of organizations (the contingency theory). As organizational effectiveness is dependent on an appropriate mix of factors, organizations may be equally effective based on differing combinations of factors. The external context of the organization is expected to influence internal organizational strategy and structure and in turn the internal measures affect performance (discriminant theory). The research considers the relationship of external context and organization performance.^ The unit of study for the research will be the health maintenance organization (HMO); an organization the accepts in exchange for a fixed, advance capitation payment, contractual responsibility to assure the delivery of a stated range of health sevices to a voluntary enrolled population. With the current Federal resurgence of interest in the Health Maintenance Organization (HMO) as a major component in the health care system, attention must be directed at maximizing development of HMOs from the limited resources available. Increased skills are needed in both Federal and private evaluation of HMO feasibility in order to prevent resource investment and in projects that will fail while concurrently identifying potentially successful projects that will not be considered using current standards.^ The research considers 192 factors measuring contextual milieu (social, educational, economic, legal, demographic, health and technological factors). Through intercorrelation and principle components data reduction techniques this was reduced to 12 variables. Two measures of HMO performance were identified, they are (1) HMO status (operational or defunct), and (2) a principle components factor score considering eight measures of performance. The relationship between HMO context and performance was analysed using correlation and stepwise multiple regression methods. In each case it has been concluded that the external contextual variables are not predictive of success or failure of study Health Maintenance Organizations. This suggests that performance of an HMO may rely on internal organizational factors. These findings have policy implications as contextual measures are used as a major determinant in HMO feasibility analysis, and as a factor in the allocation of limited Federal funds. ^

Analysis of p53 function and regulation

p53 is a tumor suppressor gene that is the most frequent target inactivated in cancers. Overexpression of wild-type p53 in rat embryo fibroblasts suppresses foci formation by other cooperating oncogenes. Introduction of wild-type p53 into cells that lack p53 arrests them at the G1/S boundary and reverses the transformed phenotype of some cells. The function of p53 in normal cells is illustrated by the ability of p53 to arrest cells at G1 phase of the cell cycle upon exposure to DNA-damaging agents including UV-irradiation and biosynthesis inhibitors.^ Since the amino acid sequence of p53 suggested that it may function as a transcription factor, we used GAL4 fusion assays to test that possibility. We found that wild-type p53 could specifically activate transcription when anchored by the GAL4 DNA binding domain. Mutant p53s, which have lost the ability to suppress foci formation by other oncogenes, were not able to activate transcription in this assay. Thus, we established a direct correlation between the tumor suppression and transactivation functions of p53.^ Having learned that p53 was a transcriptional activator, we next sought targets of p53 activation. Because many transcription factors regulate their own expression, we tested whether p53 had this autoregulatory property. Transient expression of wild-type p53 in cells increased the levels of endogenous p53 mRNA. Cotransfection of p53 together with a reporter bearing the p53 promoter confirmed that wild-type p53 specifically activates its own promoter. Deletion analysis from both the 5$\sp\prime$ and 3$\sp\prime$ ends of the promoter minimized the region responsible for p53 autoregulation to 45 bp. Methylation interference identified nucleotides involved in protein-DNA interaction. Mutations within this protected site specifically eliminated the response of the promoter to p53. In addition, multiple copies of this element confer responsiveness to wild-type p53 expression. Thus, we identified a F53 responsive element within the p53 promoter.^ The presence of a consensus NF-$\kappa$B site in the p53 promoter suggested that NF-KB may regulate p53 expression. Gel-shift experiments showed that both the p50 homodimer and the p50/p65 heterodimer bind to the p53 promoter. In addition, the p65 subunit of NF-$\kappa$B activates the p53 promoter in transient transfection experiments. TNF $\alpha$, a natural NF-$\kappa$B inducer, also activates the p53 promoter. Both p65 activation and TNF $\alpha$ induction require an intact NF-$\kappa$B site in the p53 promoter. Since NF-$\kappa$B activation occurs as a response to stress and p53 arrests cells in G1/S, where DNA repair occurs, activation of p53 by NF-$\kappa$B could be a mechanism by which cells recover from stress.^ In conclusion, we provided the first data that wild-type p53 functions as a transcriptional activator, whereas mutant p53 cannot. The correlation between growth suppression and transcriptional activation by p53 implies a pathway of tumor suppression. We have analyzed upstream components of the pathway by the identification of both p53 and NF-$\kappa$B as regulators of the p53 promoter. ^

The influence of antibacterial susceptibility and pharmacodynamics on the therapeutic response of infection

This prospective cohort study estimated how antibacterial resistance affected the time until clinical response. Relative rates of improvement and cure were estimated by proportional-hazards regression for 391 patients with culture-confirmed bacterial keratitis who had the ciprofloxacin minimal inhibitory concentration (MIC) measured of the principal corneal isolate and who were treated with ciprofloxacin 0.3% solution or ointment. After adjusting for age and hypopyon status and stratifying by ulcer size, clinic, and ciprofloxacin formulation, the summary rate of clinical improvement with ciprofloxacin therapy was reduced by 42% (95% confidence limits [CL], 3%, 65%) among patients whose corneal isolate's ciprofloxacin MIC exceeded 1.0 μg/mL compared to those with more sensitive isolates. The summary rate of resolution to improvement and cure was reduced by 36% (95% CL, 11%, 53%) among corneal infections having a higher ciprofloxacin MIC. Rate ratios were modified by the size of the presenting corneal ulceration; for ulcer diameters of 4 mm or less and of more than 4 mm, improvement rate ratios were 0.56 (95% CL, 0.31, 1.02) and 0.65 (95% CL, 0.23, 1.80), respectively; resolution rate ratios were 0.63 (95% CL, 0.44, 0.91) and 0.67 (95% CL, 0.32, 1.39), respectively. Sensitivity analysis showed that the summary improvement rate ratio could be maximally overestimated by 24% (95% CL, −29%, 114%) because of informative censoring or by 33% (95% CL, −21%, 126%) from loss to follow up. Based on reported corneal pharmacokinetics of topical ciprofloxacin, the probability of clinical improvement was 90% or more if the ratio of the achievable corneal ciprofloxacin concentration to the corneal isolate's ciprofloxacin MIC was above 8 or the ratio of the area under the 24-hour corneal concentration curve to the ciprofloxacin MIC was greater than 151. This study suggests that corneal infections by bacteria having a higher ciprofloxacin MIC respond more slowly to ciprofloxacin treatment than those with a lower MIC. While the rate of clinical resolution is affected by patient age and clinical severity, antimicrobial susceptibility testing of corneal cultures can indicate the relative effectiveness of antibacterial therapy. A pharmacodynamic approach to treating bacterial keratitis offers the prospect of optimal antimicrobial selection and modification. ^