Herculaneum victims of Vesuvius in ad 79.
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Adult↗
Biomedical subjects
M Pagano
Publications and source records attributed to M Pagano.
Cytoplasmic domain of natriuretic peptide receptor C constitutes Gi activator sequences that inhibit adenylyl cyclase activity.
We have recently demonstrated that a 37-amino acid peptide corresponding to the cytoplasmic domain of the natriuretic peptide receptor C (NPR-C) inhibited adenylyl cyclase activity via pertussis toxin (PT)-sensitive G(i) protein. In the present studies, we have used seven different peptide fragments of the cytoplasmic domain of the NPR-C receptor with complete, partial, or no G(i) activator sequence to examine their effects on adenylyl cyclase activity. The peptides used were KKYRITIERRNH (peptide 1), RRNHQEESNIGK (peptide 2), HRELREDSIRSH (peptide 3), RRNHQEESNIGKHRELR (peptide 4), QEESNIGK (peptide X), ITIERRNH (peptide Y), and ITIYKKRRNHRE (peptide Z). Peptides 1, 3, and 4 have complete G(i) activator sequences, whereas peptides 2 and Y have partial G(i) activator sequences with truncated carboxyl or amino terminus, respectively. Peptide X has no structural specificity, whereas peptide Z is the scrambled peptide control for peptide 1. Peptides 1, 3, and 4 inhibited adenylyl cyclase activity in a concentration-dependent manner with apparent K(i) between 0.1 and 1 nm; however, peptide 2 inhibited adenylyl cyclase activity with a higher K(i) of about 10 nm, and peptides X, Y, and Z were unable to inhibit adenylyl cyclase activity. The maximal inhibitions observed were between 30 and 40%. The inhibition of adenylyl cyclase activity by peptides 1-4 was absolutely dependent on the presence of guanine nucleotides and was completely attenuated by PT treatment. In addition, the stimulatory effects of isoproterenol, glucagon, and forskolin on adenylyl cyclase activity were inhibited to different degrees by these peptides. These results suggest that the small peptide fragments of the cytoplasmic domain of the NPR-C receptor containing 12 or 17 amino acids were sufficient to inhibit adenylyl cyclase activity through a PT-sensitive G(i) protein. The peptides having complete structural specificity of G(i) activator sequences at both amino and carboxyl termini were more potent to inhibit adenylyl cyclase activity as compared with the peptides having a truncated carboxyl terminus, whereas the truncation of the amino-terminal motif completely attenuates adenylyl cyclase inhibition.
Adenylyl Cyclase Inhibitors↗
Role of the F-box protein Skp2 in lymphomagenesis.
The F-box protein Skp2 (S-phase kinase-associated protein 2) positively regulates the G(1)-S transition by controlling the stability of several G(1) regulators, such as the cell cycle inhibitor p27. We show here that Skp2 expression correlates directly with grade of malignancy and inversely with p27 levels in human lymphomas. To directly evaluate the potential of Skp2 to deregulate growth in vivo, we generated transgenic mice expressing Skp2 targeted to the T-lymphoid lineage as well as double transgenic mice coexpressing Skp2 and activated N-Ras. A strong cooperative effect between these two transgenes induced T cell lymphomas with shorter latency and higher penetrance, leading to significantly decreased survival when compared with control and single transgenic animals. Furthermore, lymphomas of Nras single transgenic animals often expressed higher levels of endogenous Skp2 than tumors of double transgenic mice. This study provides evidence of a role for an F-box protein in oncogenesis and establishes SKP2 as a protooncogene causally involved in the pathogenesis of lymphomas.
Animals↗
Regulation of the G1 to S transition by the ubiquitin pathway.
This year the most prestigious prize in medical sciences, the Lasker Award, has been presented to the three scientists who discovered the ubiquitin pathway: Aaron Ciechanover, Avram Hershko, and Alexander Varshavsky [Nature Med. 6 (2000) 1073-1081]. During a time when the scientific community was focused on understanding how proteins were synthesized, they intently pursued the novel idea that cells were programmed to selectively destroy proteins. Their work led to the identification of an elaborate system of protein degradation targeting a myriad of cellular substrates. A small protein called ubiquitin is at the center of this process. Although the ubiquitin pathway was first described in the early 1980s, it has only more recently advanced to the forefront of basic research as a significant regulatory network within the cell. The field continues to grow as new ubiquitination enzymes and novel functions of this system are identified. Scientists are focused on elucidating the mechanisms by which cells deploy the ubiquitin pathway to control levels of selected proteins, such as cell cycle regulatory proteins, transcription factors and signaling molecules. Accelerated or decelerated rates of degradation of particular substrates participate in the genesis of many human diseases. Thus, understanding the mechanisms that confer specificity to the ubiquitin system will allow the development of novel therapeutic approaches to target aberrations in this pathway underlying tumorigenesis and other human pathologies.
Animals↗
High-dose sequential (HDS) chemotherapy for high-risk non-Hodgkin's lymphoma: long-term analysis and future developments.
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Adolescent↗
A comparative meta-analysis on the variability in test performance among FDA-licensed enzyme immunosorbent assays for HIV antibody testing.
BACKGROUND: Although independently published studies have compared diagnostic test performance among various manufactured enzyme immunosorbent assays (EIAs) used in HIV antibody testing, none have attempted to formally synthesize such results through a comparative meta-analysis. In particular, no estimates of post-FDA approval test performance, in terms of sensitivity and specificity, and their associated variability within each manufacturer, has been reported in the literature, along with an analysis of the relative differences in manufacturer test performance in practice (after FDA approval). METHODS: Retrieval of studies was done using several searching strategies, while retrieval of manufacturer information was done through package inserts and direct contacts. Comparisons of HIV antibody test performance across manufacturers and within a single manufacturer were made based on 16 estimates (from 11 articles) and 33 estimates (from 19 articles), respectively. A generalized linear model, based upon Bayes estimates of sensitivity and specificity, was used to assess the impact of several study-level covariates on the performance of these EIAs, with overall estimates of manufacturer test performance and associated variability obtained based on generalized estimating equations. RESULTS: Estimates of test performance were obtained across studies, with a significant (P < 0.01) difference between manufacturers. The test performance of each manufacturer significantly interacted (P < 0.05) with the following study-level covariates: type of population screened, year of diagnostic testing and study quality. Among a single manufacturer, Abbott, significant improvement in estimates of test sensitivity (P < 0.01) and specificity (P < 0.01) was observed with each newly produced antibody kit. CONCLUSION: Estimates on the relative differences in test performance within each manufacturer may be used for guiding decisions on the choice of EIA test kit for HIV antibodies, given the type of population screened, as well as cost and time considerations. In addition, the results of this meta-analysis may be used in modeling HIV prevalence when used as prior information within a Bayesian framework or for standardizing test results among various manufacturers.
Bayes Theorem↗
Sequential immunohistochemical p53 expression in biopsies of oral lichen planus undergoing malignant evolution.
Transformation in squamous cell carcinoma (SCC) may occur in a small percentage of patients affected by oral lichen planus (OLP), but the pathogenesis remains to be elucidated. Overexpression of p53 protein was investigated immunohistochemically in 28 cases of OLP, followed up by sequential biopsies for up to 96 months. In 15 cases (Group 1), no dysplastic changes or neoplastic transformation occurred during the follow-up period; in 7 cases, OLP and SCC were synchronously observed (Group 2), whereas in another 6 cases (Group 3) SCC developed several months or years after diagnosis of OLP. The percentage of p53-positive epithelial cells at first diagnosis was significantly higher in the cases of Groups 2 and 3 than in those of Group 1. In contrast, evaluation of growth fraction by MIB-1 monoclonal antibody did not show any statistical differences among the three groups. Although no conclusions can be drawn about the molecular pathway leading to neoplastic transformation of OLP, or about the role of p53, the results indicate that immunohistochemical evaluation of p53 expression may be a practical tool to select cases of OLP with a high risk of neoplastic transformation.
Aged↗
The cell-cycle regulatory protein Cks1 is required for SCF(Skp2)-mediated ubiquitinylation of p27.
The cyclin-dependent kinase (CDK) inhibitor p27 is degraded in late G1 phase by the ubiquitin pathway, allowing CDK activity to drive cells into S phase. Ubiquitinylation of p27 requires its phosphorylation at Thr 187 (refs 3, 4) and subsequent recognition by S-phase kinase associated protein 2 (Skp2; refs 5-8), a member of the F-box family of proteins that associates with Skp1, Cul-1 and ROC1/Rbx1 to form an SCF ubiquitin ligase complex. However, in vitro ligation of p27 to ubiquitin could not be reconstituted by known purified components of the SCFSkp2 complex. Here we show that the missing factor is CDK subunit 1 (Cks1), which belongs to the highly conserved Suc1/Cks family of proteins that bind to some CDKs and phosphorylated proteins and are essential for cell-cycle progression. Human Cks1, but not other members of the family, reconstitutes ubiquitin ligation of p27 in a completely purified system, binds to Skp2 and greatly increases binding of T187-phosphorylated p27 to Skp2. Our results represent the first evidence that an SCF complex requires an accessory protein for activity as well as for binding to its phosphorylated substrate.
CDC2-CDC28 Kinases↗
Prevalence of overweight and obesity in a rural southern Italy population and relationships with total and cardiovascular mortality: the Ventimiglia di Sicilia project.
OBJECTIVE: We investigated the prevalence of overweight and obesity and their relationships with the main cardiovascular risk factors in the population of Ventimiglia di Sicilia, a rural village in Southern Italy characterized by low cholesterol levels and by a low incidence of early coronary heart disease mortality. We related all deaths to body weight and fat distribution during an 8 y follow-up. DESIGN: Cross-sectional and prospective observational study. SUBJECTS: A total of 835 free-living individuals, 363 males and 472 females, of age between 20 and 69 y. MEASUREMENTS: In all participants body weight, waist-to-hip ratio (WHR), cardiovascular risk factors and plasma lipids were measured. During the follow-up, total and cardiovascular deaths were registered. RESULTS: We found a high overall prevalence of subjects with overweight or obesity (respectively 45.0% and 27.7%), with great differences among classes of age. As expected, body weight and fat distribution were associated with diabetes, hypertension, dyslipidemia and with a worsening of lipid profile. During the follow-up we registered 37 total and 11 cardiovascular deaths. All-cause and cardiovascular mortality risks were, respectively, 1.64 (95% CI 0.65-4.15) and 2.71 (95% CI 0.29-25.26) in subjects with a body mass index (BMI) of 27-29.99 kg/m2 and 2.45 (95% CI 1.03-5.87) and 5.36 (95% CI 1.41-62.01) in subjects with a BMI of > or =30 kg/m2 in comparison with participants with a BMI of <27 kg/m2, and 3.48 (95% CI 1.46-8.30) and 4.55 (95% CI 1.12-18.40) in subjects with a WHR higher than the median in comparison with individuals with a WHR lower than the median. CONCLUSION: The Ventimiglia di Sicilia Study highlights the great importance of overweight and obesity as a public health issue in a rural population and indicates that it is necessary to consider the impact of body weight and fat distribution on both total and CHD mortality.
Adult↗
Antenatal glucocorticoid treatment does not reduce chronic lung disease among surviving preterm infants.
BACKGROUND: Antenatal glucocorticoid treatment (AGT) is associated with a number of postnatal benefits to the preterm infant, including reduced risk of respiratory distress syndrome, patent ductus arteriosus, intraventricular hemorrhage, and necrotizing enterocolitis. OBJECTIVE: To evaluate the hypothesis that maternal AGT not only reduces the risk of surfactant deficiency but also reduces the occurrence of chronic lung disease (CLD) among surviving preterm infants. STUDY DESIGN: Case-referent study of 1454 very low birth weight infants born between January 1991 and December 1993 at 4 university medical centers. RESULTS: Rates of AGT varied among the 4 centers (11%-69%), as did rates of CLD (4%-21%), defined as a requirement for supplemental oxygen at 36 weeks' postmenstrual age. CLD rates at each center, however, did not vary with the rate of AGT exposure. In multivariate logistic regression analyses, AGT did not contribute significantly to CLD risk. CONCLUSION: AGT may play a less prominent role in modifying CLD risk than other factors such as biologic immaturity, infection, or neonatal intensive care unit practices, such as mechanical ventilation, continuous positive airway pressure, and surfactant replacement therapy.
Chronic Disease↗
A nonparametric scoring algorithm for identifying informative genes from microarray data.
Microarray data routinely contain gene expression levels of thousands of genes. In the context of medical diagnostics, an important problem is to find the genes that are correlated with given phenotypes. These genes may reveal insights to biological processes and may be used to predict the phenotypes of new samples. In most cases, while the gene expression levels are available for a large number of genes, only a small fraction of these genes may be informative in classification with statistical significance. We introduce a nonparametric scoring algorithm that assigns a score to each gene based on samples with known classes. Based on these scores, we can find a small set of genes which are informative of their class, and subsequent analysis can be carried out with this set. This procedure is robust to outliers and different normalization schemes, and immediately reduces the size of the data with little loss of information. We study the properties of this algorithm and apply it to the data set from cancer patients. We quantify the information in a given set of genes by comparing its distribution of the score statistics to a set of distributions generated by permutations that preserve the correlation structure among the genes.
Algorithms↗
Use of the pediatric symptom checklist in strategies to improve preventive behavioral health care.
OBJECTIVE: The purpose of this study was to examine the utility of the Pediatric Symptom Checklist (PSC) in identifying youth at risk of behavioral health problems and to develop strategies to meet their mental health needs. METHODS: The PSC was completed by the parents of 570 children aged two to 18 years at three urban health centers in Massachusetts. Follow-up interviews were conducted with the parents of 95 of the children. Multidisciplinary teams held case conferences to review the cases of 43 of the 95 children who were interviewed and who were determined to have moderate to severe behavioral health problems. RESULTS: Of the 570 children in the screening sample, 144 (25 percent) had moderate to severe behavioral health problems, as indicated by a positive score on the PSC, and 2 percent had a serious emotional disturbance. Of the 297 pre-school-aged children (younger than six years), 67 (23 percent) received a positive score. Of the 283 school-aged children (age six and older) from both English- and Spanish-speaking families, 77 (27 percent) received a positive score. About one-third of the severely emotionally disturbed youth were receiving some mental health treatment, but only 20 percent were rated by the multidisciplinary team as receiving adequate treatment. CONCLUSIONS: The study provided further support for the validity and reliability of the PSC and confirmed the results of earlier studies that found a high level of unmet needs for mental health services among this population. Use of the PSC in this study promoted an increase in referrals for children in need.
Adolescent↗
Topography of cerebral white-matter disease of prematurity studied prospectively in 1607 very-low-birthweight infants.
The objective of this study was to evaluate to what extent (1) the characteristics of localization, distribution, and size of echodense and echolucent abnormalities enable individuals to be designated as having either periventricular hemorrhagic infarction or periventricular leukomalacia and (2) the characteristics of periventricular hemorrhagic infarction and periventricular leukomalacia are independent occurrences. The population for this study consisted of 1607 infants with birthweights of 500 to 1500 g, born between January 1991 and December 1993, who had at least one cranial ultrasound scan read independently by at least two ultrasonographers. The ultrasound data collection form diagrammed six standard coronal views. The cerebrum was divided into 17 zones in each hemisphere. All abnormalities were described as being echodense or echolucent and were classified on the basis of their size, laterality, location, and evolution. Eight percent (134/1607) of infants had at least one white-matter abnormality. The prevalence of white-matter disease decreased with increasing gestational age. Most abnormalities were small or medium sized and unilateral; only large echodensities tended to be bilateral and asymmetric. Large abnormalities, whether echodense or echolucent, were more likely than smaller abnormalities to be widespread, and the extent of cerebral involvement was independent of whether abnormalities were unilateral or bilateral. Large abnormalities were relatively more likely than small abnormalities to involve anterior planes. Small abnormalities, whether echodense or echolucent, or whether unilateral or bilateral, preferentially occurred near the trigone. Using the characteristics of location, size, and laterality/symmetry, we were able to allocate only 53% of infants with white-matter abnormalities to periventricular hemorrhagic infarction or periventricular leukomalacia. Assuming that periventricular leukomalacia and periventricular hemorrhagic infarction are independent and do not share risk factors, and that each occurs in approximately 5% of infants, we would have expected 0.25%, or about 4 individuals, to have abnormalities with characteristics of both periventricular leukomalacia and periventricular hemorrhagic infarction, whereas we found 63 such infants. Most infants with white-matter disease could not be clearly designated as having periventricular hemorrhagic infarction or periventricular leukomalacia only. Periventricular hemorrhagic infarction contributes to the risk of periventricular leukomalacia occurrence, or the two sorts of abnormalities share common risk antecedent factors. The descriptive term echodense or echolucent and the generic term white-matter disease of prematurity should be used instead of periventricular leukomalacia or periventricular hemorrhagic infarction when referring to sonographically defined white-matter abnormalities.
Brain Mapping↗
Hypocarbia during the first 24 postnatal hours and white matter echolucencies in newborns < or = 28 weeks gestation.
The purpose of the present study was to test the hypothesis that newborns < or = 28 wk gestation who have a PCO(2) measurement in the lowest gestational age-specific quartile (hypocarbia) on the first day of life are not at increased risk for ultrasonographic white matter echolucency (EL) after adjustment for confounders. The sample consisted of 799 infants < or = 28 wk gestation born during 1991-1993. Forty-eight infants with EL were classified as cases and compared with 751 controls, i.e. those without EL. We performed univariable comparisons, stratified analyses, and multivariable logistic regression. In the univariable analyses, hypocarbia on the first day of life was associated with an increased EL risk. The odds ratios for the hypocarbia-EL relationship were prominently elevated in the strata of infants who did not have other major risk factors for EL (e.g. gestational age 26-28 wk, normothyroxinemia, no characteristics of antenatal infection). In the multivariable analyses, the association diminished after adjustment with a hypocarbia propensity score (odds ratio = 1.7; 95 % confidence interval, 0.8-3.2) or with potential confounders.
Brain↗
Control of murine cytomegalovirus replication in salivary glands during acute infection is independent of the Fas ligand/Fas system.
The course of mouse cytomegalovirus (MCMV) infection was compared between mutant C57BL/6 (B6) mice deficient in either perforin (perf-/-), or perforin, granzyme A and B (perfxgzmAxB-/-), and B6 gld mice lacking functionally active Fas ligand to elucidate the contribution of the two main cytolytic pathways in the early control of MCMV infection. At 15 and 30 days post infection (p.i.) virus titers were elevated in salivary glands of perf-/- and perfxgzmAxB-/-, but almost undetectable in those of mutant gld and C57BL/6 wild-type mice. No virus was detectable in lung and spleen tissues of the mutant or B6 mice at the time points tested. At 15 days p.i., scanty lymphocytic periductal infiltration was seen in salivary glands of perf-/- and perfxgzmAxB-/; these pathological alterations were minimal at 30 days p.i.. In contrast, no pathological alterations were seen in the respective organs of infected B6 and gld mice at the two time points p.i.. At 15 days p.i., reactive follicles were observed in the white pulp of spleen tissues from both mutant and B6 mice, but at 30 days p.i. only in those of mutant mice. No inflammatory responses were seen in the lung tissues of any of the four mouse strains tested. Together with previous observations (Riera et al.. 2000), the results demonstrate that both perforin and granzymes A/B, but not the FasL/Fas system are critical for viral elimination in salivary glands during the acute phase of infection. However, for the long-term control of MCMV infection, neither of the two cytolytic pathways seem to be necessary.
Acute Disease↗
The cyclin dependent kinase inhibitor p27 and its prognostic role in breast cancer.
p27 is an inhibitor of cyclin dependent kinase involved in the regulation of the cell cycle. In this commentary we discuss the current knowledge on p27 in breast cancer and its significance in predicting the outcome. p27 protein levels are high in most cases of breast carcinomas, are correlated with the levels of cyclin D1 and estrogen receptor, and could be a useful predictor of survival, because they are low in aggressive carcinomas. Immunodetection of p27 in breast tumors could be useful in the assessment of prognosis, especially in those cases in which the commonly used parameters are insufficient, and might ultimately influence the therapy of this disease.
Breast Neoplasms↗
Insights into SCF ubiquitin ligases from the structure of the Skp1-Skp2 complex.
F-box proteins are members of a large family that regulates the cell cycle, the immune response, signalling cascades and developmental programmes by targeting proteins, such as cyclins, cyclin-dependent kinase inhibitors, IkappaBalpha and beta-catenin, for ubiquitination (reviewed in refs 1-3). F-box proteins are the substrate-recognition components of SCF (Skp1-Cullin-F-box protein) ubiquitin-protein ligases. They bind the SCF constant catalytic core by means of the F-box motif interacting with Skp1, and they bind substrates through their variable protein-protein interaction domains. The large number of F-box proteins is thought to allow ubiquitination of numerous, diverse substrates. Most organisms have several Skp1 family members, but the function of these Skp1 homologues and the rules of recognition between different F-box and Skp1 proteins remain unknown. Here we describe the crystal structure of the human F-box protein Skp2 bound to Skp1. Skp1 recruits the F-box protein through a bipartite interface involving both the F-box and the substrate-recognition domain. The structure raises the possibility that different Skp1 family members evolved to function with different subsets of F-box proteins, and suggests that the F-box protein may not only recruit substrate, but may also position it optimally for the ubiquitination reaction.
Amino Acid Sequence↗
The F-box protein family.
SUMMARY: The F-box is a protein motif of approximately 50 amino acids that functions as a site of protein-protein interaction. F-box proteins were first characterized as components of SCF ubiquitin-ligase complexes (named after their main components, Skp I, Cullin, and an F-box protein), in which they bind substrates for ubiquitin-mediated proteolysis. The F-box motif links the F-box protein to other components of the SCF complex by binding the core SCF component Skp I. F-box proteins have more recently been discovered to function in non-SCF protein complexes in a variety of cellular functions. There are 11 F-box proteins in budding yeast, 326 predicted in Caenorhabditis elegans, 22 in Drosophila, and at least 38 in humans. F-box proteins often include additional carboxy-terminal motifs capable of protein-protein interaction; the most common secondary motifs in yeast and human F-box proteins are WD repeats and leucine-rich repeats, both of which have been found to bind phosphorylated substrates to the SCF complex. The majority of F-box proteins have other associated motifs, and the functions of most of these proteins have not yet been defined.
Animals↗