Hematopoietic cells from gadd45a-deficient and gadd45b-deficient mice exhibit impaired stress responses to acute stimulation with cytokines, myeloablation and inflammation

The gadd45 family of gene(s) is rapidly induced by genotoxic stress or by differentiation-inducing cytokines. Using bone marrow (BM) from gadd45a-/-, gadd45b-/- and wild-type (wt) mice, we investigated their role in stress responses of myeloid cells to acute stimulation with differentiating cytokines, myelotoxic agents and inflammatory substances. Bone marrow cells from gadd45a-/- and gadd45b-/- mice displayed compromised myeloid differentiation and higher apoptosis in vitro, following acute stimulation with a variety of differentiating cytokines. Intriguingly, gadd45a-/- and gadd45b-/- colony forming units granulocyte/macrophage progenitors displayed prolonged proliferation capacity compared to wt controls upon re-plating in methylcellulose supplemented with interleukin-3. The recovery of the BM myeloid compartment following 5-Fluorouracil-induced myelo-ablation was much slower in gadd45a-/- and gadd45b-/- mice compared to wt controls. Furthermore, the response of myeloid cells to inflammatory stress, inflicted via intraperitoneal administration of sodium caseinate was impaired in gadd45a-/- and gadd45b-/- mice compared to age-matched wt mice, as indicated by lower percentage of Gr-1-positive cells in the BM and lower number of myeloid cells in peritoneal exudates. Overall, these data indicate that both gadd45a and gadd45b play a role in modulating physiological stress responses of myeloid cells to acute stimulation with differentiating cytokines, myelo-ablation and inflammation. These findings should aid in understanding the response of normal and malignant hematopoietic cells to physiological and chemical stressors including anticancer agents.

Overexpression of an epitope-tagged serotonin transporter in serotonin neurons of the dorsal raphe nucleus using a defective HSV-1 vector

The serotonin transporter (5HTT) plays a central role in serotonin neurotransmission. Abnormalities of 5HTT function have been implicated in depression, anxiety and alcohol intake. To better understand the functional role of this important molecule, we have utilized a viral vector approach to overexpress the 5HTT in regions of the rat brain. We have constructed a bicistronic defective herpes virus (HSV-1) vector that expresses both an epitope-tagged 5HTT as well as beta-galactosidase (beta-GAL) as a marker for infected cells. The vector was capable of conferring serotonin uptake activity to Vero cells in culture, indicating transfer of a functional 5HTT. Injection of the 5HTT virus into the rat brain resulted in a dense focus of specific 125I RTI-55 binding at the injection site, indicating that the virally expressed 5HTT can also bind ligand when expressed in the brain. We were also able to overexpress an epitope tagged 5HTT in serotonergic neurons in the dorsal raphe nucleus (DRN) using this approach. These data demonstrate that the levels of the 5HTT in 5HT neurons can be manipulated in the adult rodent brain using an HSV-1 vector.

Myeloid differentiation (MyD)/growth arrest DNA damage (GADD) genes in tumor suppression, immunity and inflammation

Myeloid differentiation (MyD) primary response and growth arrest DNA damage (Gadd) genes comprise a set of overlapping genes, including known (IRF-1, EGR-1, Jun) and novel (MyD88, Gadd45alpha, MyD118/Gadd45beta, GADD45gamma, MyD116/ Gadd34) genes, that have been cloned by virtue of being co-ordinately induced upon the onset of terminal myeloid differentiation and following exposure of cells to stress stimuli. In recent years it has become evident that MyD/Gadd play a role in blood cell development, where they function as positive regulators of terminal differentiation, lineage-specific blood cell development and control of blood cell homeostasis, including growth inhibition and apoptosis. MyD/Gadd are also involved in inflammatory responses to invading micro-organisms, and response to environmental stress and physiological stress, such as hypoxia, which results in ischemic tissue damage. An intricate network of interactions among MyD/GADD genes and gene products appears to control their diverse functions. Deregulated growth, increased cell survival, compromised differentiation and deficiencies in DNA repair are hallmarks of malignancy and its progression. Thus, the role MyD/Gadd play in negative growth control, including cell cycle arrest and apoptosis, and in DNA repair, make them attractive molecular targets for tumor suppression. The role MyD/Gadd play in innate immunity and host response to hypoxia also make these genes and gene products attractive molecular targets to treat immunity and inflammation disorders, such as septic shock and ischemic tissue damage.

Methyl analogues of the experimental Alzheimer drug phenserine: synthesis and structure/activity relationships for acetyl- and butyrylcholinesterase inhibitory action

With the goal of developing potential Alzheimer's pharmacotherapeutics, we have synthesized a series of novel analogues of the potent anticholinesterases phenserine (2) and physostigmine (1). These derivatives contain methyl (3, 4, 6), dimethyl (5, 7, 8, 10, 11) and trimethyl (14) substituents in each position of the phenyl group of the phenylcarbamoyl moieties, and with N-methyl and 6-methyl substituents (12, 13, 31, 33). We also quantified the inhibitory action of these compounds against human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). An analysis of the structure/anticholinesterase activity relationship of the described compounds, together with molecular modeling, confirmed the catalytic triad mechanism of the binding of this class of carabamate analogues within AChE and BChE and defined structural requirements for their differential inhibition.

Immunopathology of secondary-progressive multiple sclerosis

Twenty-three plaques obtained at early autopsy from 2 patients with secondary-progressive multiple sclerosis were examined immunohistochemically for microglia/macrophages, and for immunoglobulins and components of activated complement. Most of the lesions examined in both cases exhibited evidence of low-grade active demyelination of an unusual type (frustrated phagocytosis) in periplaque white matter. This included linear groups of microglia engaging short segments of disrupted myelin that were associated with deposits of C3d, an opsonin formed during complement activation. Similar microglia/C3d/myelin profiles were not observed in newly forming lesions in cases of acute multiple sclerosis or other central white matter diseases. As C3d coupling is known to increase the immunogenicity of potential antigens enormously, present findings point to disrupted myelin close to plaques as a possible source of the putative multiple sclerosis antigen. Ongoing myelin destruction found in a high proportion of old, established plaques was surprising. It suggests that slowly expanding lesions (progressive plaques), in which ongoing myelin breakdown occurs in the absence of florid perivascular cell cuffing or other histological signs of acute inflammation, contribute to disease progression in cases of secondary-progressive multiple sclerosis.

Methods for identifying methicillin resistancein Staphylococcus aureus

Five methods for the detection of methicillin-resistant Staphylococcus aureus were used to examine a collection of 100 clinical isolates comprising both susceptible and resistant strains. The disc diffusion test with oxacillin had a sensitivity of 93.3% and a specificity of 92.0% whereas mannitol salt agar containing oxacillin had a sensitivity of 100% and specificity 80.6% with high inoculum. With a low inoculum the sensitivity was 90.7% and specificity 96.0%. The MRSA screen test (Denka Seiken Co. Ltd., Japan) and Evigene MRSA Detection Kit (State Serum Institute, Denmark) tests were in complete agreement with results obtained with polymerase chain reaction assays amplifying mecA and nuc gene sequences.

Ectopic expression of MyD118/Gadd45/CR6 (Gadd45beta/alpha/gamma) sensitizes neoplastic cells to genotoxic stress-induced apoptosis

The MyD118/Gadd45/CR6 gene family (also termed Gadd45beta/alpha/gamma) has been identified as genes which are rapidly induced by genotoxic agents, during terminal differentiation, as well as by apoptotic cytokines. In recent years, evidence has emerged that the proteins encoded by these genes play pivotal roles in negative growth control, including growth suppression and apoptotic cell death. However, under what physiological condition these proteins mediate either cell cycle arrest or apoptosis, and the molecular nature of apoptotic pathways involved are currently unclear. Thus, to further explore the effects of these genes on cell growth and cell viability, either in the presence or absence of extrinsic stress, we have established M1 myeloblastic leukemia and H1299 lung carcinoma cell lines, where high level ectopic expression of MyD118, Gadd45, or CR6 can be induced by isopropyl beta-D-thiogalactopyranoside (IPTG). By taking advantage of these cell lines, it was observed that in the absence of genotoxic stress, inducible expression of MyD118, Gadd45 and/or CR6 resulted in retardation of cellular proliferation and accumulation of cells in the G1 phase of the cell cycle. Ectopic expression of these proteins also was found to sensitize the cells to apoptosis induced by genotoxic agents such as UV, MMS, gamma-irradiation and VP16. Finally, evidence has been obtained that in the absence of stress, ectopic expression of MyD118/Gadd45/CR6 is insufficient to activate the MTKl/JNK/p38 stress cascade, and that enhancement of genotoxic stress induced apoptosis by these proteins may involve apoptotic pathways other than the JNK/p38 pathways.

Comparative analysis of the genetic structure and chromosomal location of the murine MyD118 (Gadd45beta) gene

The MyD118 (Gadd45beta) protein is a member of a family of structurally related proteins, including Gadd45 (Gadd45alpha) and CR6 (Gadd45gamma), that have critical roles in regulating growth arrest and apoptosis. The MyD118 and other members of its family display distinct patterns of expression in response to stimuli that induce differentiation, growth arrest, or apoptosis. Species-blot analysis showed that MyD118 is an evolutionarily conserved gene, and comparative sequence analysis showed that MyD118 has a gene structure similar to that of other members of its gene family. Comparison of putative transcription factor-binding sites found in sequences of this gene family provides evidence that p53 is involved in regulating the expression of MyD118 and that NF-kappaB may play a role in differential expression of MyD118 and Gadd45(Gadd45alpha). Fluorescence in situ hybridization localized the MyD118 gene to mouse chromosome band 10B5.3, correcting a previous assignment to mouse chromosome 9.

Early growth response gene 1 stimulates development of hematopoietic progenitor cells along the macrophage lineage at the expense of the granulocyte and erythroid lineages

Using a variety of differentiation-inducible myeloid cell lines, we previously showed that the zinc-finger transcription factor early growth response gene 1 (Egr-1) is a positive modulator of macrophage differentiation and negatively regulates granulocytic differentiation. In this study, high-efficiency retroviral transduction was used to ectopically express Egr-1 in myeloid-enriched or stem cell-enriched bone marrow cultures to explore its effect on the development of hematopoietic progenitors in vitro and in lethally irradiated mice. It was found that ectopic Egr-1 expression in normal hematopoietic progenitors stimulates development along the macrophage lineage at the expense of development along the granulocyte or erythroid lineages, regardless of the cytokine used. Moreover, Egr-1 accelerated macrophage development by suppressing the proliferative phase of the growth-to-macrophage developmental program. The remarkable ability of Egr-1 to dictate macrophage development at the expense of development along other lineages resulted in failure of Egr-1-infected hematopoietic progenitors to repopulate the bone marrow and spleen, and thereby prevent death, in lethally irradiated mice. These observations further highlight the role Egr-1 plays in monocytic differentiation and growth suppression.

Interaction of CR6 (GADD45gamma ) with proliferating cell nuclear antigen impedes negative growth control

GADD45, MyD118, and CR6 (also termed GADD45alpha, beta, and gamma) comprise a family of genes that encode for related proteins playing important roles in negative growth control, including growth suppression. Data accumulated suggest that MyD118/GADD45/CR6 serve similar but not identical functions along different apoptotic and growth suppressive pathways. It is also apparent that individual members of the MyD118/GADD45/CR6 family are differentially induced by a variety of genetic and environmental stress agents. The MyD118, CR6, and GADD45 proteins were shown to predominantly localize within the cell nucleus. Recently, we have shown that both MyD118 and GADD45 interact with proliferating cell nuclear antigen (PCNA), a protein that plays a central role in DNA replication, DNA repair, and cell cycle progression, as well as with the universal cyclin-dependent kinase inhibitor p21. In this work we show that also CR6 interacts with PCNA and p21. Moreover, it is shown that CR6 interacts with PCNA via a domain that also mediates interaction of both GADD45 and MyD118 with PCNA. Importantly, evidence has been obtained that interaction of CR6 with PCNA impedes the function of this protein in negative growth control, similar to observations reported for MyD118 and GADD45.

Interobserver agreement for EUS in the evaluation and diagnosis of submucosal masses

INTRODUCTION

EUS is an accurate means of evaluating and diagnosing submucosal lesions of the GI tract. The aim of this study was to prospectively determine interobserver agreement for the EUS classification of submucosal masses among endosonographers with different levels of training and experience from multiple centers.

METHODS

Twenty patients with submucosal mass lesions diagnosed by upper endoscopy underwent EUS. Surgical findings were available for 16 patients. In 4 patients with obvious cystic/vascular structures (i.e., varices) no surgical specimen was necessary. A blinded observer developed a study videotape of critical endoscopic and EUS real-time imaging for each lesion. The videotape was distributed to 10 endosonographers, each with at least 1 year of experience, who independently reviewed the videotape and recorded their diagnosis based on EUS features. These endosonographers used previously agreed-upon standardized EUS diagnostic criteria for each category of lesion. A kappa (kappa) statistic, used to evaluate agreement, was calculated for each lesion category for the 10 endosonographers as a group and individually. An overall kappa statistic was also calculated. Significance was analyzed with a two-tailed t test.

RESULTS

Agreement was excellent for cystic lesions (kappa = 0.80) and extrinsic compressions (kappa = 0.94), good for lipoma (kappa = 0.65), fair for leiomyoma and vascular lesions (kappa = 0.53 and 0.54, respectively), and poor for other submucosal lesions (kappa = 0.34). Overall agreement among observers was good (kappa = 0.63). Furthermore, a significant association was noted between total years of EUS experience and the number of correct answers (p = 0.01).

CONCLUSIONS

Interobserver agreement is good for characterizing submucosal masses by EUS. However, it appears to be better for some lesions than others. The overall length of experience with EUS appears to play an important role in the accuracy of this modality in the evaluation of submucosal lesions.

Human DNA-demethylating activity: a glycosylase associated with RNA and PCNA

We have partially purified and characterized the 5-methylcytosine removing activity (5-meC-DNA Glycosylase) from HeLa cells with 700-fold enrichment. This activity cleaves DNA specifically at fully methylated CpG sites. The mechanism of 5-meC removal is base excision from fully methylated CpG loci on DNA, producing abasic sites. Hemi-methylated DNA is not a substrate. A prominent 52 KDa protein is present in all partially purified fractions. This activity is tightly associated with other nuclear factors and proteins, which resulted in differential fractionation of this activity on ion exchange columns. One nuclear factor associated with this activity is identified as RNA. Another nuclear protein, proliferating cell nuclear antigen (PCNA) is also associated with this enzyme. Glycosylic removal of 5-meC from DNA by this activity could be involved in the regulation of transcription, replication, differentiation, and development through resultant hypomethylation of DNA.

Deregulated E2F-1 blocks terminal differentiation and loss of leukemogenicity of M1 myeloblastic leukemia cells without abrogating induction of p15(INK4B) and p16(INK4A)

The transcription factor E2F-1 has been postulated to play a crucial role in the control of cell cycle progression because of its ability to be bound and regulated by the retinoblastoma gene product (pRb). Exogenous expression of E2F-1, under growth restrictive conditions, was shown to result in p53-dependent programmed cell death. The consequences of deregulated expression of E2F-1 on terminal differentiation of hematopoietic cells in the absence of E2F-1-mediated apoptosis, as well as mechanistic insights into how deregulated E2F-1 may affect terminal differentiation, have not been established. The autonomously proliferating M1 myeloblastic leukemia cell line, which is null for p53 expression and can be induced by interleukin-6 (IL-6) to undergo terminal macrophage differentiation with concomitant loss of leukemogenicity, provides a particularly attractive model system to address these issues. Deregulated and continued expression of E2F-1 blocked the IL-6-induced terminal differentiation program at an early blast stage, giving rise to immature cells, which continued to proliferate without undergoing apoptosis and retained their leukemogenic phenotype. Although E2F-1 blocked IL-6-mediated terminal differentiation and its associated growth arrest, it did not prevent the rapid induction of both p15(INK4B) and p16(INK4A), inhibition of cdk4 kinase activity, and subsequent hypophosphorylation of pRb. The results obtained imply that genetic alterations that both impair p53 function and deregulate E2F-1 expression may render hematopoietic cells refractory to the induction of differentiation and are, thereby, likely to play a major role in the progression of leukemias. (Blood. 2000;96:475-482)

p53-independent apoptosis associated with c-Myc-mediated block in myeloid cell differentiation

Previously we have shown that deregulated expression of c-myc in M1 myeloid leukemic cells blocked IL-6-induced differentiation and its associated growth arrest; however, the cells proliferated at a significantly reduced rate compared to untreated cells. The basis for the increased doubling time of IL-6-treated M1myc cells was found to be due to the induction of a p53-independent apoptotic pathway. The apoptotic response was not completely penetrant; in the same population of cells both proliferation and apoptosis were continuously ongoing. Down-regulation of Bcl-2 was insufficient to account for the apoptotic response, since deregulated expression of Bcl-2 delayed, but did not block, the onset of apoptosis. Furthermore, our results indicated that the IL-6-induced partial hypophosphorylation of the retinoblastoma gene product (Rb), observed in M1myc cells, was not responsible for the apoptotic response. Finally, the findings in M1 cells were extended to myeloid cells derived from the bone marrow of wild type and p53-deficient mice, where the deregulated expression of c-myc was also shown to block terminal differentiation and induce apoptosis independent of p53. These findings provide new insights into how myc participates in the neoplastic process, and how additional mutations can promote more aggressive tumors. Oncogene (2000) 19, 2967 - 2977

Characterization of MyD118, Gadd45, and proliferating cell nuclear antigen (PCNA) interacting domains. PCNA impedes MyD118 AND Gadd45-mediated negative growth control

MyD118 and Gadd45 are related genes encoding for proteins that play important roles in negative growth control, including growth suppression and apoptosis. MyD118 and Gadd45 are related proteins that previously were shown to interact with proliferating cell nuclear antigen (PCNA), implicated in DNA replication, DNA repair, and cell cycle progression. To establish the role of MyD118 and Gadd45 interactions with PCNA, in this work we sought to identify the interacting domains and analyze the significance of this interaction in negative growth control. Using complementary in vivo and in vitro interaction assays the N-terminal (1-46) and middle (100-127) regions of PCNA were identified as harboring MyD118- and Gadd45 interacting domains, whereas PCNA interacting domains within MyD118 and Gadd45 were localized to the C termini of these proteins (amino acids 114-156 and 137-165, respectively). These findings provide first evidence that similar domains within MyD118 and Gadd45 mediate interactions with PCNA. Importantly, ectopic expression of MyD118 or Gadd45 N-terminal peptides, lacking the PCNA interacting domain, was found to suppress colony formation or induce apoptosis more efficiently than the full-length proteins. These findings suggest that interaction of MyD118 or Gadd45 with PCNA, in essence, serves to impede negative growth control.

Cdc25A stability is controlled by the ubiquitin-proteasome pathway during cell cycle progression and terminal differentiation

Members of the cdc25 family are protein phosphatases that play pivotal roles in cell cycle progression. Cdc25A has been shown to be a critical regulator of the G1/S transition of mammalian cells and to be a myc-target gene with oncongenic properties. We investigated the regulation of cdc25A during terminal differentiation using myeloblastic leukemia M1 cells, that can be induced to undergo differentiation into macrophages by interleukin-6 (IL-6) treatment. In this report it is shown that cdc25A protein is degraded by the ubiquitin-proteasome machinery in both terminally differentiating and cycling cells. Cdc25A was found to have two major peaks of accumulation during cell cycle progression, one in G1 and the other in S/G2. Evidence was obtained that degradation of cdc25A by the ubiquitin-proteasome machinery in terminally differentiating myeloid cells is accelerated compared to cycling cells. Moreover, deregulated expression of c-myc in M1 cells, which had been previously shown to block terminal differentiation, was also found to block IL-6 induced degradation of cdc25A.

Cost-efficacy of endoscopic ultrasonography with fine-needle aspiration vs. mediastinotomy in patients with lung cancer and suspected mediastinal adenopathy

BACKGROUND AND STUDY AIMS

The use of endoscopic ultrasonography (EUS) guidance for fine-needle aspiration (FNA) of mediastinal lymph nodes has become an important aid in the staging of bronchogenic carcinoma. In many cases, it may be an alternative to mediastinoscopy/mediastinotomy (MED), but the cost-effectiveness of the two techniques has not been compared. The aim of this study was to apply a decision-analysis model to compare the cost-effectiveness of EUS and MED in the preoperative staging of patients with non-small-cell lung cancer.

PATIENTS AND METHODS

A decision-analysis model was designed, taking as entry criteria lung cancer and abnormal mediastinal lymph nodes verified by computerized tomography (CT). Performance characteristics of MED and EUS were retrieved from the published literature, as were life expectancy data. Direct actual costs of the relevant procedures were retrieved from the billing system of our hospital.

RESULTS

The cost per year of expected survival is US$ 1.729 with the EUS strategy, and US$ 2.411 with the MED strategy. The advantage conferred by EUS remains even when the negative predictive value of EUS is as low as 0.22.

CONCLUSION

Because of its low cost and high yield, EUS-guided FNA is a cost-effective aid assessing mediastinal lymphadenopathy.

Phenolic constituents, furans, and total antioxidant status of distilled spirits

The concentrations of 11 phenols and 5 furans were measured in 12 categories of distilled spirits by HPLC methodology, together with the total antioxidant status (TAS) of the same beverages. Ellagic acid was the phenol present in highest concentration in all beverages. Moderate amounts of syringaldehyde, syringic acid, and gallic acid, as well as lesser amounts of vanillin and vanillic acid, were measurable in most samples of whiskey, brandy, and rum but were largely undetectable in gin, vodka, liqueurs, and miscellaneous spirits. 5-(Hydroxymethyl)furfural was the predominant furan in the former three beverages, notably cognac, with 2-furaldehyde the next highest, but these were undetectable in most of the latter beverages. Highest TAS values were given by armagnac, cognac, and bourbon whiskey, all three of which tended toward the highest concentrations of phenols. Negative TAS values were exhibited by rum, vodka, gin, and miscellaneous spirits in line with the low or undetectable phenol concentrations in these beverages. Wood aging is the most likely source of phenols and furans in distilled spirits. Those beverages exposed to this treatment contain significant antioxidant activity, which is between the ranges for white and red wines, with the potential to augment the antiatherosclerotic functions attributable to the ethanol that they contain.

Interleukin-6 and leukemia inhibitory factor induction of JunB is regulated by distinct cell type-specific cis-acting elements

Interleukin (IL)-6 plays an important role in a wide range of biological activities, including differentiation of murine M1 myeloid leukemic cells into mature macrophages. At the onset of M1 differentiation, a set of myeloid differentiation primary response (MyD) genes are induced, including the proto-oncogene for JunB. In order to examine the molecular nature of the mechanisms by which IL-6 activates the immediate early expression of MyD genes, JunB was used as a paradigm. A novel IL-6 response element, -65/-52 IL-6RE, to which a 100-kDa protein complex is bound, has been identified on the JunB promoter. Leukemia inhibitory factor (LIF)-induced activation of JunB in M1 cells was also mediated via the -65/-52 IL-6RE. The STAT3 and CRE-like binding sites of the JunB promoter, identified as IL-6-responsive elements in HepG2 liver cells were found, however, to play no role in JunB inducibility by IL-6 in M1 myeloid cells. Conversely, the -65/-52 IL-6RE is shown not to be necessary for JunB inducibility by IL-6 or LIF in liver cells. It appears, therefore, that immediate early activation of JunB is regulated differently in M1 myeloid cells than in HepG2 liver cells. This indicates that distinct cis-acting control elements participate in cell type-specific induction of JunB by members of the IL-6 cytokine superfamily.

CR6: A third member in the MyD118 and Gadd45 gene family which functions in negative growth control

MyD118 and Gadd45 are two related genes which encode for proteins that play important roles in negative growth control, including both growth suppression and apoptosis. A strategy was employed to clone new members of the MyD118 and Gadd45 family of genes. Based on alignment of the deduced amino acid sequences, one cDNA clone was found to encode for the murine homologue of human CR6, originally cloned as an IL-2 immediate-early response gene. The murine and human CR6 proteins were observed to be 97% identical, indicating that CR6 is an evolutionarily conserved protein. Analysis of CR6 expression during hematopoietic cell development associated with growth arrest and apoptotic cell death, upon exposure of hematopoietic cells to a variety of growth arrest and apoptotic stimuli, and in a variety of murine tissues, has revealed that CR6 expression differs significantly from the expression of the related MyD118 and Gadd45 genes. Nevertheless, CR6, like MyD118 and Gadd45, suppressed colony formation of human lung carcinoma H1299 cells. These data suggest that CR6 plays similar, but not identical, roles to MyD118 and Gadd45 in negative control of cell growth.

Quantitative structure-activity relationship modeling of dopamine D(1) antagonists using comparative molecular field analysis, genetic algorithms-partial least-squares, and K nearest neighbor methods

Several quantitative structure-activity relationship (QSAR) methods were applied to 29 chemically diverse D(1) dopamine antagonists. In addition to conventional 3D comparative molecular field analysis (CoMFA), cross-validated R(2) guided region selection (q(2)-GRS) CoMFA (see ref 1) was employed, as were two novel variable selection QSAR methods recently developed in one of our laboratories. These latter methods included genetic algorithm-partial least squares (GA-PLS) and K nearest neighbor (KNN) procedures (see refs 2-4), which utilize 2D topological descriptors of chemical structures. Each QSAR approach resulted in a highly predictive model, with cross-validated R(2) (q(2)) values of 0.57 for CoMFA, 0.54 for q(2)-GRS, 0.73 for GA-PLS, and 0.79 for KNN. The success of all of the QSAR methods indicates the presence of an intrinsic structure-activity relationship in this group of compounds and affords more robust design and prediction of biological activities of novel D(1) ligands.

Cancer survivors' employment and insurance rights: a primer for oncologists

Cancer survivors' access to equal employment opportunities and adequate health insurance has changed significantly during the 1990s. New federal and state laws have expanded survivors' rights to be treated fairly in the workplace, although some problems still exist. Survivors have experienced less progress, however, in obtaining and retaining adequate health insurance. This article reviews the problems faced by cancer survivors in securing and keeping adequate employment and health insurance.

Prospective assessment of the utility of EUS in the evaluation of gallstone pancreatitis

BACKGROUND

The ability to identify common bile duct stones by noninvasive means in patients with acute biliary pancreatitis is limited. The aim of this study was to prospectively evaluate the ability of endosonography (EUS) to identify cholelithiasis and choledocholithiasis and predict disease severity in patients with nonalcoholic pancreatitis.

METHODS

EUS was performed immediately before endoscopic retrograde cholangiopancreatography (ERCP) by separate blinded examiners within 72 hours of admission. Gallbladder findings were compared between EUS and transabdominal ultrasonography (US). Using endoscopic extraction of a bile duct stone as the reference standard for choledocholithiasis, the diagnostic yield of EUS was compared with transabdominal US and ERCP. Features identified during endosonographic imaging of the pancreas were correlated with length of hospitalization.

RESULTS

Thirty-six patients were studied. EUS and transabdominal US were concordant in their interpretation of gallbladder findings in 92% of patients. The sensitivity of transabdominal US, EUS, and ERCP for identifying choledocholithiasis was 50%, 91%, and 92% and the accuracy was 83%, 97%, and 89%, respectively. Length of hospital stay was longer in patients with peripancreatic fluid (9.2 vs. 5.7 days, p < 0.1) and shorter in patients with coarse echo texture (2.6 vs. 7.2 days, p < 0.05) demonstrated on EUS.

CONCLUSIONS

EUS can reliably identify cholelithiasis and is more sensitive than transabdominal US in detecting choledocholithiasis in patients with biliary pancreatitis. EUS may be used early in the management of patients with acute pancreatitis to select those who would benefit from endoscopic stone extraction. The utility of EUS for predicting pancreatitis severity requires further investigation.