Biomedical subjects
Publications and source records attributed to M Hogan.
A novel series of anthranilic acid-based inhibitors of MMP-1, MMP-9, MMP-13, and TACE was prepared and evaluated. Selective inhibitors of MMP-9, MMP-13, and TACE were identified, including the potent, orally active MMP-13 inhibitor 4p.
The double helix is known to form as a result of hybridization of complementary nucleic acid strands in aqueous solution. In the helix the negatively charged phosphate groups of each nucleic acid strand are distributed helically on the outside of the duplex and are available for interaction with cationic groups. Cation-coated glass surfaces are now widely used in biotechnology, especially for covalent attachment of cDNAs and oligonucleotides as surface-bound probes on microarrays. These cationic surfaces can bind the nucleic acid backbone electrostatically through the phosphate moiety. Here we describe a simple method to fabricate DNA microarrays based upon adsorptive rather than covalent attachment of oligonucleotides to a positively charged surface. We show that such adsorbed oligonucleotide probes form a densely packed monolayer, which retains capacity for base pair-specific hybridization with a solution state DNA target strand to form the duplex. However, both strand dissociation kinetics and the rate of DNase digestion suggest, on symmetry grounds, that the target DNA binds to such adsorbed oligonucleotides to form a highly asymmetrical and unwound duplex. Thus, it is suggested that, at least on a charged surface, a non-helical DNA duplex can be the preferred structural isomer under standard biochemical conditions.
Short oligonucleotide probes have been linked to a solid support by simple electrostatic adsorption onto a positively charged surface film. Attachment was obtained by microfluidic application of unmodified oligonucleotides in distilled water onto amino-silanized glass. It has been demonstrated that an extremely stable monolayer of oligonucleotide is obtained by this method, at a density of about 10(11) molecules/mm(2), which approaches the limit expected for a two-dimensional closest-packed array. Application of oligonucleotide by adsorption is followed by capping with acetic anhydride in the vapor phase, and then capping with succinic anhydride in solution to form a surface with weak negative charge. The capping method has been successfully employed for microarray fabrication and for the analysis of single nucleotide polymorphisms in the k-ras gene. The data reveal that, subsequent to capping, the adsorptive association of oligonucleotide to the surface yields a probe layer which is capable of single nucleotide base mismatch discrimination and high apparent binding affinity.
Hybridization rate enhancement has been demonstrated for high molecular weight DNA target binding to a microarray. Microarrays were fabricated using biotin-modified oligonucleotides complexed with streptavidin (SA), which serves as an attachment to the underlying surface. It is shown that at low salt and pH 5, where SA develops a positive charge, duplex formation becomes at least 80-fold faster than seen under standard conditions, where SA is neutral or anionic. Duplex formation becomes independent of solution state cation concentration in the low pH state, under conditions where specificity remains high. The utility of such applied surface science is discussed.
BACKGROUND: A logical progression of the widely used microtiter plate ELISA is toward a protein array format that allows simultaneous detection of multiple analytes at multiple array addresses within a single well. Here we describe the construction and use of such a multiplex ELISA to measure prostate-specific antigen (PSA), alpha1-antichymotrypsin-bound PSA (PSA-ACT), and interleukin-6 (IL-6). METHODS: We silanized glass plates and printed the appropriate capture antibodies to allow for the construction of "sandwich" ELISA quantification assays. We examined specificity of the assay for appropriate antigen, assembled calibration curves, and obtained PSA concentrations for 14 human serum samples. We compared the serum PSA concentrations derived through the use of our array with values obtained independently using a standard ELISA method. RESULTS: R2 values generated by our microarray for the PSA and PSA-ACT calibration curves were 0.989 and 0.979, respectively. Analyte concentrations used for the construction of these curves were 0.31-20 microg of protein/L of diluent. IL-6 calibration curve concentrations were 4.9-300 ng of IL-6/L of diluent. The R2 value for the IL-6 calibration curve was 0.983. The 14 human serum samples screened by this micro-ELISA technique for PSA concentrations generated a regression equation (linear) with a slope of 0.83 +/- 0.10 and intercept of 0.74 +/- 0.70 (R2 = 0.88). CONCLUSIONS: Multiplexed ELISA arrays are a feasible option for analyte quantification in complex biologic samples.
We live in a media world and the mass media offer educational and entertainment opportunities for adults and children. However, pediatricians and parents are increasingly aware of the potential health risks that media exposure presents to children and adolescents. For many years, the American Academy of Pediatrics (AAP) has made media education a key goal for member pediatricians: Six policy statements about the impact of mass media have been published (and revised) over the past decade. In 1997, the AAP launched a 5-year, nationwide media education campaign called Media Matters. Although education about media is the cornerstone of Media Matters, pediatricians have other important roles. In offices and clinics, the AAP suggests that pediatricians take a media history from patients and discuss connections between a child's health and behavior and media use habits. Pediatricians can also provide anticipatory guidance to families about media in the home, including limiting media use, making wise media choices, encouraging co-viewing and critical thinking, and making the home a positive media environment. Many gaps in our knowledge about the effects of media images and messages on young people still exist; pediatricians call for ongoing, targeted research about media. In this way, we can all enjoy the benefits offered by media, while minimizing the risks.
PURPOSE: To study retrospectively the incidence of ventilator-associated pneumonia (VAP) at the time of Pseudomonas aeruginosa nosocomial bloodstream infection (BSI) and at the time of P aeruginosa airway colonization. MATERIALS AND METHODS: Fifteen very low-birth-weight infants who had P aeruginosa BSI and 33 others who did not but who had P aeruginosa airway-colonization were studied. We correlated clinical data, blood cultures (BCs), and tracheal cultures (TCs) with radiologic findings from radio-graphs taken within 2 days before, the day of, and 1 day after BCs or TCs were first positive for P aeruginosa. Chest radiographs were graded by using semiquantitative scores for bronchopulmonary dysplasia and for pneumonia. RESULTS: Mean birth weight, gestational age, and age when BC or TC became positive were similar for patients with BSI and colonization. At the time of BSI, 2 infants had airway colonization with P aeruginosa; the TCs of the remaining 13 grew P aeruginosa as a new pathogen. Thirteen of 15 patients with BSI, but none of 33 infants with colonization, died within 2 days of positive BC. VAP was diagnosed in 13 of 15 patients with BSI and in 3 of 33 infants with colonization. CONCLUSION: Mechanically ventilated very low-birth-weight infants whose TCs yield P aeruginosa but whose BCs remain negative infrequently have VAP are presumed airway-colonized and are expected to survive. Conversely, VAP is likely to be found when BCs and TCs simultaneously grow P aeruginosa, and high mortality is anticipated.
The sensitivity of six fluorophores to glutathione (GSH) was evaluated in living rat cortical neuronal/glial mixed cultures during the first 23 days in vitro (DIV). Four of the dyes require glutathione-S-transferase (GST) to form a fluorescent conjugate, potentially conferring specificity for GSH: these included t-butoxycarbonyl-Leu-Met-7-amino-4-chloromethylcoumarin (CMAC), 7-amino-4-chloromethylcoumarin (CMAC-blue), monochlorobimane (MCB), and 5-chloromethylfluorescein diacetate (CMFDA). The final two dyes examined, 2,3-naphthalenedicarboxaldehyde (NDA) and o-phthaldehyde (OPD), do not require GST for adduct formation with GSH. To examine the specificity of the dyes for GSH, cultures grown less than 6 DIV were pretreated with diethyl maleate or DL-buthionine-(S, R)-sulfoximine to deplete endogenous GSH. This resulted in a substantial loss of staining by CMAC, CMAC-blue, and MCB and partial loss of staining by OPD, indicating specificity for GSH, while staining by CMFDA or NDA was not altered, indicating a lack of specificity for GSH. Neurons experienced a dramatic decline in GSH levels relative to astrocytes between 5-6 DIV, as shown by a loss of neuronal staining with CMAC, CMAC-blue and MCB. This decrease in staining was not due to a decrease in GST activity, as neurons stained with the GST-insensitive OPD also exhibited a decline in GSH-sensitive staining. Immunolabeling experiments demonstrated that CMAC staining co-localized with GFAP-positive astrocytes, but not with MAP-2-positive neurons, in 18 DIV cultures. Finally, CMAC was exploited as a specific morphological marker of astrocytes in cultures aged >5 DIV. CMAC staining was employed to monitor astrocyte proliferation and to resolve astrocytes in living mixed cultures co-loaded with the Ca(2+)-sensitive dye, calcium green 5N-AM. GLIA 30:329-341, 2000. Published 2000 Wiley-Liss, Inc.
Ca2+ influx and activation of protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) during nonlethal ischemic preconditioning have been implicated in the protection of the heart against subsequent lethal ischemic injury. Thus, we determined if Ca2+ influx, PKC and MAPK also mediate ischemic preconditioning-induced protection in neurons. Preconditioning by exposure of E18 rat cortical cultures to 90 min of nonlethal oxygen-glucose deprivation (OGD) 24 h prior to 180-240 min of lethal OGD was neuroprotective. Exposure to nominally free Ca2+, or blockade of the alpha-amino-hydroxy-5-methyl-isoxazolepropionate (AMPA) receptor with CNQX did not eliminate protection. MAPK activity did not change and PKC activity decreased by 50% relative to normal baseline levels at 0 and 24 h following preconditioning. The sustained decrease in PKC activity was not due to a loss of enzyme as determined from immunoblots using pan and epsilon-, beta- and zeta-specific PKC antibodies. Neuroprotection was maintained with pharmacological inhibition of PKC activity by staurosporine, chelerythrine and calphostin C and MAPK activity by PD 98059 during preconditioning, indicating that activation of these enzymes during preconditioning was not necessary for protection. Therefore, in contrast to cardiac tissue, ischemic preconditioning of neurons does not require activation of PKC and MAP kinase, and protection is maintained with substantial removal of extracellular Ca2+ or blockade of the AMPA receptor.
Joubert's syndrome is a well-documented but rare disorder characterized by a variable combination of central nervous system, respiratory, renal and eye anomalies. The most significant and constant neuropathological finding is partial or complete agenesis of the cerebellar vermis. The syndrome was first described by Joubert and colleagues as a familial agenesis of the cerebellar vermis and appears to be inherited as an autosomal recessive trait. A case of Joubert's syndrome is described in which second-trimester ultrasonography demonstrated abnormal findings in the fetal posterior fossa with associated renal abnormalities. However, postnatal sonography of the posterior fossa could not confirm the prenatal findings, and the diagnosis of Joubert's syndrome was only later established by computed tomography of the neonatal brain in the knowledge of the characteristic clinical picture.
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An interdisciplinary continuum-of-care process achieves a unit's mission and enhances team excellence. Quality of patient care improves, costs decrease, staff satisfaction and morale increase, and a sense of team integration emerges. Strategic planning is an effective tool to actualize this process.
Comparative genomic hybridization (CGH) was used in a retrospective analysis of chromosomal imbalances in frozen primary tumor specimens from 14 endometrial carcinoma patients. Chromosome changes were detected in nine cases (64%), and tumor stage and grade tended to parallel the degree of genomic imbalances. Gain of the entire long arm of chromosome 1 was observed in six cases (43%), three of which displayed only this chromosome change. Other common sites of copy number increases included 8q21-->qter (4 cases), 10p15 (4 cases), 10q11-->q24 (3 cases), and 13q21-->qter (3 cases, each with stage III disease). Two of the tumors with gains of chromosome 10 involved the whole chromosome, and this was the sole abnormality in one case. DNA amplification at 5p14-->p15 was identified in one specimen, a stage III tumor having numerous imbalances. DNA microsatellite analysis revealed multiple replication errors (RER), indicative of the RER+ phenotype, in four of 13 (31%) cases evaluated. The RER+ phenotype was observed in four of six stage la tumors but in none of seven stage Ib or stage III tumors. Multiple genomic imbalances detected by CGH were not observed in RER+ tumors but were detected in five of nine tumors without the RER+ phenotype. These investigations demonstrate the feasibility of CGH for the retrospective assessment of chromosomal changes in endometrial carcinoma specimens. Moreover, these data suggest that the etiologies in tumors with and without the RER+ phenotype may differ.
OBJECTIVE: Little research addresses the correlates of sexual aggression in nonclinical populations of adolescents. The purpose of this study was to identify risk and protective factors associated with sexual violence among male and female adolescents. METHODS: We analyzed data on 71,594 students in the 9th and 12th grades responding to the 1992 Minnesota Student Survey, an anonymous, self-report survey examining an array of risk environments, health-compromising behaviors, and protective factors. The responses of students reporting a history of forcing someone into a sexual act were compared with those who reported that they had never forced someone into a sexual act. Separate analyses were conducted for males and females. RESULTS: A history of sexual violence perpetration was reported by 4.8% of male and 1.3% of female adolescents. Using a logistic regression model, sexual aggression was associated with experiencing intrafamilial or extrafamilial sexual abuse, witnessing family violence, frequent use of illegal drugs, anabolic steroid use, daily alcohol use, gang membership, high levels of suicide risk behavior, and excessive time spent "hanging out." Emotional health and connectedness with friends and adults in the community were protective factors for male adolescents against sexually aggressive behavior, and academic achievement was a protective factor for female adolescents. CONCLUSIONS: A history of forcing someone into a sexual act was associated with several risk and protective factors. Efforts to prevent adolescent sexual violence should target individuals at increased risk. Through their psychosocial assessment of young people, health care professionals can play a role in identifying, counseling, and making appropriate referrals for adolescents at risk for sexually aggressive behavior.
Pulmonary surfactant phosphatidylcholine synthesis increases in fetal lung type II cells with advancing gestation. This increase is accompanied by an increase in gene and protein expression of CTP:phosphocholine cytidylyltransferase (CT; EC 2.7.7.15), which catalyses a regulatory step in de novo phosphatidylcholine synthesis by fetal type II cells. In the present study we investigated the role of transcriptional and post-transcriptional mechanisms in the developmental induction of CT mRNA in maturing type II cells. We found that CT mRNA increased 2-fold from days 18 to 21 of fetal rat gestation (term 22 d). This increase in CT mRNA was not accompanied by a developmental increase in CT gene transcription. However, CT mRNA was more stable on day 21 (t1/2 48 h) compared with that on day 18 (t1/2 17 h). Glucocorticoids have been shown to enhance surfactant phosphatidylcholine synthesis in fetal type II cells. Therefore we also examined the effect of maternal glucocorticoid administration to pregnant rats at 19 d of gestation on CT mRNA expression in fetal type II cells isolated 24 h later. Glucocorticoid treatment did not increase type II cell CT mRNA. As reported previously, however, glucocorticoids increased CT activity in the microsomal membrane fraction of fetal type II cells, whereas no differences in cytosolic CT activity were observed. We conclude that the developmental increase in CT mRNA in fetal type II cells is due to a decreased breakdown of the CT transcript and that glucocorticoids regulate fetal type II cell CT activity at a post-translational level.
Objective. To determine whether ileoileocolic intussusception can be diagnosed by a distinctive appearance during pneumatic reduction. Materials and methods. We reviewed the clinical, pathologic, and imaging findings of 11 patients with ileoileocolic intussusceptions seen in our hospital between January 1989 and July 1994. The patients ranged in age from 4 months to 4 years and 2 months. We specifically evaluated the appearance of these intussusceptions on air enemas performed in nine of these patients. Another 22 air enemas of all patients with surgically proven ileocolic intussusception seen during the same time period were also reviewed for comparison. Results. In seven of the nine patients with ileoileocolic intussusception who had air enemas, the intussusceptum clearly had two or more separate polypoid components once it was reduced to the cecum. This distinctive appearance was not seen until the intussusceptum was tethered at the ileocecal valve. The intussusceptum was also reduced to the cecum in 19 patients from the control group with ileocolic intussusception. In contrast to the ileoileocolic intussusceptums, these intussusceptums were either smoothly marginated (16 patients) or slightly lobular (three patients). Conclusion. In most patients with ileoileocolic intussusception, the intussusceptum has two or more polypoid components at the level of the ileocecal valve which are easily distinguished from the smoothly marginated or slightly lobular intussusceptum seen with ileocolic intussusception.
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