Polygamain, a new microtubule depolymerizing agent that occupies a unique pharmacophore in the colchicine site.

Bioassay-guided fractionation was used to isolate the lignan polygamain as the microtubule-active constituent in the crude extract of the Mountain torchwood, Amyris madrensis. Similar to the effects of the crude plant extract, polygamain caused dose-dependent loss of cellular microtubules and the formation of aberrant mitotic spindles that led to G(2)/M arrest. Polygamain has potent antiproliferative activities against a wide range of cancer cell lines, with an average IC(50) of 52.7 nM. Clonogenic studies indicate that polygamain effectively inhibits PC-3 colony formation and has excellent cellular persistence after washout. In addition, polygamain is able to circumvent two clinically relevant mechanisms of drug resistance, the expression of P-glycoprotein and the ßIII isotype of tubulin. Studies with purified tubulin show that polygamain inhibits the rate and extent of purified tubulin assembly and displaces colchicine, indicating a direct interaction of polygamain within the colchicine binding site on tubulin. Polygamain has structural similarities to podophyllotoxin, and molecular modeling simulations were conducted to identify the potential orientations of these compounds within the colchicine binding site. These studies suggest that the benzodioxole group of polygamain occupies space similar to the trimethoxyphenyl group of podophyllotoxin but with distinct interactions within the hydrophobic pocket. Our results identify polygamain as a new microtubule destabilizer that seems to occupy a unique pharmacophore within the colchicine site of tubulin. This new pharmacophore will be used to design new colchicine site compounds that might provide advantages over the current agents.

[Monitoring aminoglycosides in an Intensive Care Unit]. / Monitorage des aminosides en réanimation.

OBJECTIVES: This monocentric, observational and retrospective survey was performed to check the appropriateness between aminoglycoside prescriptions and inhibitor quotient to be reached, in Intensive Care Unit (ICU) patients. We identified variability factors for aminoglycoside plasmatic concentrations at peak such as standardized index of gravity (IGS2 scale), age, sex, weight, and severity of sepsis. PATIENTS AND METHOD: Eighty-seven ICU patients received an antibiotic combination mandatorily including an aminoglycoside (amikacin or gentamicin) as curative treatment for a severe infection. Prescribed dosages were 15mg/kg for amikacin and 5mg/kg for gentamicin. The maximal concentration (Cmax) and minimal inhibiting concentration (MIC) of involved bacteria were recorded. The aminoglycoside ratio Cmax/MIC, called inhibitor quotient, was determined. The inhibitor quotient was considered efficient when superior to 10. The Cmax for aminoglycoside first peak was also compared with the theoretical Cmax to be reached. RESULTS: In the aminoglycoside Cmax, 50.3% were efficient (59.6% for amikacin Cmax and 38.9% for gentamicin Cmax). In 46% of the cases, the inhibitor quotient was efficient; 12.6% of Cmax reached the theoretical Cmax. Factors identified as negatively interacting with biological efficiency were: Gram-positive bacteria or anaerobic bacteria infections and planned surgery. CONCLUSION: In the inhibitor quotients, 49.7% were at inefficient rates, even when the recommended aminoglycoside dosage for was given. Therefore, dose and administration should be updated.

Progress in cancer screening over a decade: results of cancer screening from the 1987, 1992, and 1998 National Health Interview Surveys.

BACKGROUND: Screening to detect cancer early, an increasingly important cancer control activity, cannot be effective unless it is widely used. METHODS: Use of Pap smears, mammography, fecal occult blood tests (FOBTs), sigmoidoscopy, and digital rectal examination (DRE) was evaluated in the 1987, 1992, and 1998 National Health Interview Surveys. Levels and trends in screening use were examined by sex, age, and racial/ethnic group. The effects of income, educational level, and health care coverage were examined within age groups. Logistic regression analyses of 1998 data were used to develop a parsimonious, policy-relevant model. RESULTS: Use of all screening modalities increased over the period examined; for mammography and DRE, the increase was more rapid in the first half of the decade; for the Pap test and sigmoidoscopy, the increase was more rapid in the second half of the decade. Levels of colorectal cancer screening (both sigmoidoscopy and FOBTs) in 1998 were less than the level that prevailed a decade earlier for mammography. Patterns of change for all screening modalities differed between age, sex, and racial/ethnic groups, but prevalence of use during the study, within recommended time intervals, was consistently lower among groups with lower income and less education. Logistic regression analyses indicated that insurance coverage and, to a greater extent, usual source of care had strong independent associations with screening usage when age, sex, racial/ethnic group, and educational level were taken into account. CONCLUSIONS: While cancer screening is generally increasing in the United States, usage is relatively low for colorectal cancer screening and among groups that lack health insurance or a usual source of care.

The effects of environmental tobacco smoke on children: Information and implications for PNPs.

Although much information is available about the harmful effects of smoking and exposure to environmental tobacco smoke (ETS), many children are in contact with ETS in their home every day. Health effects related to ETS vary from minor nasal irritation to an increased susceptibility to sudden infant death syndrome. ETS can also cause future health problems as exposed children become adults. Assessment of ETS exposure is an essential component of a patient's health history, and parents should be educated about the harmful effects of ETS and how to protect young children from it. Strategies for prevention of ETS exposure must be pursued to ensure improved health outcomes for all children.

Bowel surveillance patterns after a diagnosis of colorectal cancer in Medicare beneficiaries.

BACKGROUND: Postoperative colon surveillance has been recommended for patients with a diagnosis of local/regional colorectal cancer. The extent to which these recommendations are followed in practice is poorly characterized. Patterns of surveillance after surgery for colorectal cancer were determined by using a large population-based database. METHODS: This is a retrospective cohort study with cancer registry data linked to Medicare claims. Identified were 52,283 patients treated for local/regional colorectal cancer between 1986 and 1996, and surveillance patterns through 1998 were determined. Surveillance patterns were analyzed by using survival analysis and by computing the proportion of surviving patients who underwent procedures during 4 time periods after treatment: 2 to 14 months, 15 to 50 months, 51 to 86 months and more than 87 months. RESULTS: Median times to first through fifth surveillance events were 20, 14, 15, 15, and 15 months, respectively. For 17% of the cohort there was no surveillance event. Younger patients were more likely to undergo surveillance. Surveillance patterns were not affected by stage. The proportions of the cohort that underwent no surveillance during the 4 respective time periods were 54%, 52%, 60%, and 69%. The percentages of patients who underwent surveillance annually or more frequently in the latter 3 time periods, respectively, were 19%, 10%, and 5%, or 11% overall, treating the data for the 3 events as a whole. Over the period from 1986 to 1998, the proportion of patients who had no surveillance procedures gradually decreased, whereas the proportion of those who underwent procedures annually or more frequently remained relatively constant. CONCLUSIONS: During the period from 1986 to 1998 there was low utilization of postdiagnosis colon surveillance in a substantial proportion of elderly patients with a diagnosis of local/regional colorectal cancer. Over time there was a trend toward increasing receipt of any surveillance procedures. The percentages of patients undergoing surveillance annually or more frequently did not change between earlier and later periods.

Parathyromatosis: a cause for recurrent hyperparathyroidism.

OBJECTIVE: To report a case of parathyromatosis as a cause for recurrent hyperparathyroidism. METHODS: We present the case history, laboratory results, operative interventions, and pathologic findings in a 36-year-old woman. Relevant reports from the literature are reviewed. RESULTS: Our patient, who had been undergoing long-term hemodialysis because of renal failure, presented with secondary hyperparathyroidism and progressive bone pain. After an uneventful subtotal parathyroidectomy (removal of 3-1/2 glands), her symptoms resolved in conjunction with normalization of parathyroid hormone levels. Subsequently, however, recurrent hyperparathyroidism and severe bone pain necessitated second and third neck explorations, during which parathyromatosis was discovered. A total thyroidectomy was performed because of the bilateral nature of the disease. Postoperatively, the patient's bone pain resolved substantially, although her parathyroid hormone levels remained high. CONCLUSION: Parathyromatosis is a rare cause of recurrent hyperparathyroidism after parathyroidectomy. It consists of hyperfunctioning parathyroid tissues scattered throughout the neck, due either to intraoperative tissue spillage and subsequent implantation or to hyperplasia of parathyroid rests from embryologic development. This is one of the few case reports of parathyromatosis and the first case report of a mixed form of the disease, consisting of features of both subcapsular parathyroid rests and extracapsular implantation.

The burden of illness of cancer: economic cost and quality of life.

Cancer is a major public health issue and represents a significant burden of disease. In this chapter, we analyze the main measures of burden of disease as relate to cancer. Specifically, we review incidence and mortality, years of life lost from cancer, and cancer prevalence. We also discuss the economic burden of cancer, including cost of illness, phase-specific and long-term costs, and indirect costs. We then examine the impact of cancer on health-related quality of life as measured in global terms (disability-adjusted life years and quality-adjusted life years) and using evaluation-oriented applications of health-related quality of life scales. Throughout, we note the relative strengths and weaknesses of the various approaches to measuring the burden of cancer as well as the methodologic challenges that persist in burden-of-illness research. We conclude with a discussion of the research agenda to improve our understanding of the burden of cancer and of illness more generally.

Design, synthesis, and evaluation of novel A2A adenosine receptor agonists.

We have been interested in the design, synthesis, and evaluation of novel adenosine A2A agonists. Through the use of comparative molecular field analysis (CoMFA) we have generated a training model that includes 78 structurally diverse A2A agonists and correlated their affinity for isolated rat brain receptors with differences in their structural and electrostatic properties. We validated this model by predicting the activity of a test set that included 24 additional A2A agonists. Our CoMFA model, which incorporates the physiochemical property of dipole and selects against A1 receptor activity, generated a correlated final model (r2 = 0.891) that provides for enhanced A2A selectivity and predictability. Synthesis, pharmacological evaluation, and modeling of four novel ligands further validate the utility and predictive power (r2 = 0.626) of the CoMFA model.

A macrophage receptor for apolipoprotein B48: cloning, expression, and atherosclerosis.

We have cloned a human macrophage receptor that binds to apolipoprotein (apo)B48 of dietary triglyceride (TG)-rich lipoproteins. TG-rich lipoprotein uptake by the apoB48R rapidly converts macrophages and apoB48R-transfected Chinese hamster ovary cells in vitro into lipid-filled foam cells, as seen in atherosclerotic lesions. The apoB48R cDNA (3,744 bp) encodes a protein with no known homologs. Its approximately 3.8-kb mRNA is expressed primarily by reticuloendothelial cells: monocytes, macrophages, and endothelial cells. Immunohistochemistry shows the apoB48R is in human atherosclerotic lesion foam cells. Normally, the apoB48R may provide essential lipids to reticuloendothelial cells. If overwhelmed, foam cell formation, endothelial dysfunction, and atherothrombogenesis may ensue, a mechanism for cardiovascular disease risk of elevated TG.

Endoscopic colorectal cancer screening: a cost-saving analysis.

BACKGROUND: Comprehensive analyses have shown that screening for cancer usually induces net costs. In this study, the possible costs and savings of endoscopic colorectal cancer screening are explored to investigate whether the induced savings may compensate for the costs of screening. METHODS: A simulation model for evaluation of colorectal cancer screening, MISCAN-COLON, is used to predict costs and savings for the U.S. population, assuming that screening is performed during a period of 30 years. Plausible baseline parameter values of epidemiology, natural history, screening test characteristics, and unit costs are based on available data and expert opinion. Important parameters are varied to extreme but plausible values. RESULTS: Given the expert opinion-based assumptions, a program based on every 5-year sigmoidoscopy screenings could result in a net savings of direct health care costs due to prevention of cancer treatment costs that compensate for the costs of screening, diagnostic follow-up, and surveillance. This result persists when costs and health effects are discounted at 3%. The "break-even" point, the time required before savings exceed costs, is 35 years for a screening program that terminates after 30 years and 44 years for a screening program that continues on indefinitely. However, net savings increase or turn into net costs when alternative assumptions about natural history of colorectal cancer, costs of screening, surveillance, and diagnostics are considered. CONCLUSIONS: Given the present, limited knowledge of the disease process of colorectal cancer, test characteristics, and costs, it may well be that the induced savings by endoscopic colorectal cancer screening completely compensate for the costs.

The scid recombination-inducible cell line: a model to study DNA-PK-independent V(D)J recombination.

To investigate the molecular mechanisms of the variable (diversity) joining (V(D)J) recombination process at an endogenous gene locus, recombination-inducible cell lines were made from both bcl-2-bearing severe combined immune deficiency (scid) homozygous and scid heterozyous (s/ + ) mice by transforming pre-B cells with the temperature-sensitive Abelson murine leukemia virus (ts-Ab-MLV). These transformants can be induced to undergo immunoglobulin light-chain gene rearrangements by incubating them at the non-permissive temperature. In the case of transformed scid cells, a significant amount of hairpin coding ends are accumulated during recombination induction, but few coding joints are generated. After being shifted to the permissive temperature. however, these cells are capable of opening hairpin ends and forming coding joints. Thus, ts-Ab-MLV transformed scid cells can be readily manipulated for both recombination cleavage and end resolution. However, unlike the rapid coding joint formation in s/ + cells that have the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), the process for resolving coding ends in scid cells is slow and error prone, and also appears to be correlated with a reduction in the RAG1/2 expression. Apparently, this process is mediated by a DNA-PK-independent pathway. The fact that the activity of this pathway can be manipulated in vitro makes it possible to delineate the mechanisms in end opening, processing and joining. Therefore, these ts-Ab-MLV transformed scid cell lines offer a model to study the molecular nature as well as the regulation of the DNA-PK-independent pathway in coding end resolution.

Metabolism of recombination coding ends in scid cells.

V(D)J recombination cleavage generates two types of dsDNA breaks: blunt signal ends and covalently sealed hairpin coding ends. Although signal ends can be directly ligated to form signal joints, hairpin coding ends need to be opened and subsequently processed before being joined. However, the underlying mechanism of coding end resolution remains undefined. The current study attempts to delineate this process by analyzing various structures of coding ends made in situ from recombination-inducible pre-B cell lines of both normal and scid mice. These cell lines were derived by transformation of B cell precursors with the temperature-sensitive Abelson murine leukemia virus. Our kinetic analysis revealed that under conditions permissive to scid transformants, hairpin coding ends could be nicked to generate 3' overhangs and then processed into blunt ends. The final joining of these blunt ends followed the same kinetics as signal joint formation. The course of this process is in sharp contrast to coding end resolution in scid heterozygous transformants that express the catalytic subunit of DNA-dependent protein kinase, in which hairpin end opening, processing, and joining proceeded very rapidly and appeared to be closely linked. Furthermore, we demonstrated that the opening of hairpin ends in scid cells could be manipulated by different culture conditions, which ultimately influenced not only the level and integrity of the newly formed coding joints, but also the extent of microhomology at the coding junctions. These results are discussed in the context of scid leaky recombination.

Obtaining long-term disease specific costs of care: application to Medicare enrollees diagnosed with colorectal cancer.

OBJECTIVES: This study develops estimates of long-term, cancer-related treatment cost using a modeling approach and data from the SEER-Medicare linked database. The method is demonstrated for colorectal cancer. METHODS: Data on Medicare payments were obtained for colorectal cancer patients for the years 1990 to 1994 from the SEER-Medicare linked database. Claims payment data for control subjects were obtained for Medicare enrollees without cancer residing in the same areas as patients. Estimates of long-term cost (< or = 25 years following the date of diagnosis) were obtained by combining treatment/phase-specific cost estimates with estimates of long-term survival from SEER. Treatment phases were defined as initial care, terminal care, and continuing care. Cancer-related estimates for each phase were obtained by subtracting costs for control subjects from the observed costs for cancer patients, matching on age group, gender, and registry area. Estimates of long-term cost < or = 11 years obtained by this method were compared with 11-year estimates obtained by application of the Kaplan-Meier sample average (KMSA) method. RESULTS: The mean initial-phase cancer-related cost was approximately $18,000 but was higher among patients with more advanced cancer. The mean continuing-phase cancer-related cost was $1,500 per year and declined with increasing age, but was higher on an annual basis among persons with later stages of cancer and shorter survival time. The mean terminal-phase cancer-related cost was $15,000 and declined with both age at death and more advanced stage at diagnosis. After the phase-specific estimates were combined, the average long-term cancer-related cost was $33,700 ($31,300 at 3% discount rate) for colon cancer compared with $36,500 ($33,800 at 3% discount rate) for cancer of the rectum. This represented about half of the total long-term cost for Medicare enrollees diagnosed with this disease. Long-term cost was highest for Stage III cancer and lowest for in situ cancer. Eleven-year cancer-related costs estimated by the KMSA method were similar to estimates using the phase-based approach. CONCLUSIONS: This paper demonstrates that valid estimates of cancer-related long-term cost can be obtained from administrative claims data linked to incidence cancer registry data.

Managed care, consolidation among health care providers, and health care: evidence from mammography.

We discuss the effects of managed care on the structure of the health care delivery system, focusing on managed-care-induced consolidation among health care providers. We empirically investigate the relationship between HMO market share and mammography providers. We find evidence of consolidation: increases in HMO activity are associated with reductions in the number of mammography providers and with increases in the number of services produced by remaining providers. We also find that increases in HMO market share are associated with reductions in costs for mammography and with increases in waiting times for appointments, but not with worse health outcomes.

Survival and treatment for colorectal cancer Medicare patients in two group/staff health maintenance organizations and the fee-for-service setting.

The current study compares treatment use and long-term survival in colorectal cancer patients between Medicare beneficiaries enrolled in two large prepaid group/staff health maintenance organizations (HMOs) and the fee-for-service (FFS) setting. The study is based on 15,352 colorectal cancer cases diagnosed between 1985 and 1992 and followed through 1995. Survival differences between the HMO and FFS cases were assessed using Cox regression. Treatment differences were evaluated using logistic regression. HMO cases had a lower overall mortality than did FFS cases but not a significantly lower colorectal cancer-specific mortality. Use of surgical resection was similar between HMO and FFS cases. However, rectal cancer cases in the HMOs were more likely to receive postsurgical radiation therapy than FFS cases. Superior overall survival in the HMOs may be the result of increased colorectal cancer screening, greater use of adjuvant therapies, and selection of healthier individuals.

Antipeptide antibodies reveal interrelationships of MBP 200 and MBP 235: unique apoB-specific receptors for triglyceride-rich lipoproteins on human monocyte-macrophages.

Two human monocyte-macrophage (HMM) membrane binding proteins, (MBP) 200 and 235, are receptor candidates that bind to the apolipoprotein (apo)B-48 domain in triglyceride-rich lipoproteins for uptake independent of apoE. Microsequence analysis of the purified reduced MBP 200R characterized tryptic peptides of MBP 200R. A synthetic peptide mimicking a unique, unambiguous 10-residue sequence (AEGLMVTGGR) induced antipeptide antibodies that specifically recognized MBP 200, 235 and 200R, in 1- and 2-dimensional analyses, indicating 1) the ligand binding protein was sequenced and 2) MBP 200 and 235 yielded MBP 200R upon reduction. These antibodies identified the MBPs in human blood-borne, THP-1, U937 MMs, and endothelial cells (EC) but not in human fibroblasts or Chinese hamster ovary (CHO) cells. Fluorescence activated cell sorting (FACS) analysis located the MBPs on the MM surface as necessary for receptor function. The 10-residue, unambiguous MBP 200-derived sequence is unique, with no matches in extant protein databases. Antipeptide antibodies bind to the MBPs in reticuloendothelial cells that have this receptor activity, but not to proteins in cells that lack this receptor activity. These studies provide the first direct protein sequence and immunochemical data that a new, unique apoB receptor for triglyceride-rich lipoproteins exists in human monocytes, macrophages, and endothelial cells.

Formation of coding joints in V(D)J recombination-inducible severe combined immune deficient pre-B cell lines.

Characterization of the severe combined immune deficient (scid) defect in the recombination process has provided many insights into the underlying mechanisms of variable (diversity) joining recombination. By using recombination-inducible scid pre-B cell lines transformed with the temperature-sensitive Abelson-murine leukemia virus, we show that large quantities of recombination intermediates can be generated, and their resolution can be followed during further cell culture. In this study, we demonstrate that the ability of these scid pre-B cell lines to resolve coding ends depends on the cell culture temperature. At the nonpermissive temperature of 39 degreesC, scid pre-B cell lines fail to form coding joints and contain mostly unresolved hairpin-coding ends. Once the cell culture is returned to the permissive temperature of 33 degreesC, these same cells make a significant amount of coding joints concomitant with the disappearance of hairpin-coding ends. Thus, the scid cells are capable of resolving coding ends under certain culture conditions. However, the majority of the recovered coding joints contains extensive deletions, indicating that the temperature-dependent resolution of coding ends is still scid-like. Our results suggest that the inability of scid cells to promptly nick hairpin-coding ends may lead to aberrant joining in these cells.