Worms start the reef-building process.
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Animals↗
Biomedical subjects
R Kelley
Publications and source records attributed to R Kelley.
Dehydro-oestriol and dehydropregnanetriol are candidate analytes for prenatal diagnosis of Smith-Lemli-Opitz syndrome.
Gas chromatographic/mass spectrometric (GC/MS) analysis of maternal urine and serum steroids from 13 pregnancies at 25% risk for Smith-Lemli-Opitz syndrome (SLOS) was undertaken. All patients were between 12 and 31 weeks' gestational age. From dehydrocholesterol/cholesterol ratios determined in amniotic fluid and chorionic villus cells, five patients were shown to carry SLOS affected fetuses and eight patients were negative for the condition. Because it had previously been shown that dehydro-oestriol and dehydropregnanetriol were novel steroids produced in SLOS, these compounds were measured in the serum and urine samples of the 13 mothers. All five urine samples from SLOS affected pregnancies had high levels of both dehydrosteroid metabolites, which were below the detection limit in the non-affected pregnancies. The ratios of dehydro-oestriol/oestriol (DHE(3)/E(3)) were between 0.073 and 1.42 for the affected patients and less than 0.01 for unaffected patients. Corresponding values for dehydropregnanetriol/pregnanetriol (DHPT/PT) were 0.037-1.02 for affected and less than 0.01 for unaffected. In the positive serum sample available for analysis, the DHE(3)/E(3) ratio was 0.20 [unaffected (n=5), <0.014]. It is proposed that the measurement of DHE(3) and DHPT in maternal urine and serum may allow non-invasive antenatal diagnosis of SLOS.
Biomarkers↗
Transgenic mice with cardiac-specific expression of activating transcription factor 3, a stress-inducible gene, have conduction abnormalities and contractile dysfunction.
Activating transcription factor 3 (ATF3) is a member of the CREB/ATF family of transcription factors. Previously, we demonstrated that the expression of the ATF3 gene is induced by many stress signals. In this report, we demonstrate that expression of ATF3 is induced by cardiac ischemia coupled with reperfusion (ischemia-reperfusion) in both cultured cells and an animal model. Transgenic mice expressing ATF3 under the control of the alpha-myosin heavy chain promoter have atrial enlargement, and atrial and ventricular hypertrophy. Microscopic examination showed myocyte degeneration and fibrosis. Functionally, the transgenic heart has reduced contractility and aberrant conduction. Interestingly, expression of sorcin, a gene whose product inhibits the release of calcium from sarcoplasmic reticulum, is increased in these transgenic hearts. Taken together, our results indicate that expression of ATF3, a stress-inducible gene, in the heart leads to altered gene expression and impaired cardiac function.
Activating Transcription Factor 3↗
Congenital rubella and interstitial pneumonitis.
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Fatal Outcome↗
On the nature of associative information in recognition memory.
In a typical associative-recognition task, participants must distinguish between intact word pairs (both words previously studied together) and rearranged word pairs (both words previously studied but as part of different pairs). The familiarity of the individual items on this task is uninformative because all of the items were seen before, so the only way to solve the task is to rely on associative information. Prior research suggests that associative information is recall-like in nature and may therefore be an all-or-none variable. The present research reports several experiments in which some pairs were strengthened during list presentation. The resulting hit rates and false alarm rates, and an analysis of the corresponding receiver operating characteristic plots, suggest that participants rely heavily on item information when making an associative-recognition decision (to no avail) and that associative information may be best thought of as a some-or-none variable.
Adult↗
Delayed diagnosis of intracranial aneurysms: confounding factors in clinical presentation and the influence of misdiagnosis on outcome.
The initial presentation of intracranial aneurysm can be missed in routine clinical practice. An underlying aneurysm may have a subtle presentation that warrants definitive diagnostic procedures. A retrospective review of 270 patients with aneurysms at our institution revealed 40 patients (14.8%) with a significant delay in diagnosis before definitive treatment. The delay due to missed diagnosis varied from 2 days to a few months. In retrospect, 58% had a Hunt and Hess grade I clinical presentation at readmission. Clinical status was rated as grade 0-I in the majority of patients (65%), grade II in 20%, and grade III in 12.5%. One patient had grade IV status. These grades are significantly different from the initial grade at which each of the patients first sought medical attention. The second admission significantly affected the outcome. A delay in diagnosis of aneurysmal subarachnoid hemorrhage resulting in poor clinical grade influenced neurologic outcome significantly.
Adolescent↗
Activation and active site occupation alter conformation in the region of the first epidermal growth factor-like domain of human factor VII.
The first epidermal growth factor-like domain (EGF-1) of factor VII (FVII) provides the region of greatest contact during the interaction of FVIIa with tissue factor. To understand this interaction better, the conformation-sensitive FVII EGF-1-specific monoclonal antibody (mAb) 231-7 was used to investigate the conformational effects occurring in this region upon both FVII activation and active site occupation. The binding affinity of mAb 231-7 was approximately 3-fold greater for the zymogen state than for the active state; a result affected by the presence of both calcium and the adjacent Gla domain. Once activated, active site inhibition of FVIIa with a variety of chloromethyl ketone inhibitors resulted in a 10-fold range of affinities of FVIIai molecules to mAb 231-7. Gla domain removal eliminated this variation in affinity, suggesting the involvement of a Gla/EGF-1 interaction in this conformational effect. In addition, the binding of mAb 231-7 to FVIIa EGF-1 stimulated the amidolytic activity of free FVIIa. Taken together, these results imply an allosteric interaction between the FVIIa active site and the EGF-1 domain that is sensitive to variation in active site occupant structure. Thus, these present studies indicate that the conformational change associated with FVII activation and active site occupation involves the EGF-1 domain and suggest potential functional consequences of these changes.
Allosteric Site↗
Macromolecular inhibitors of HIV-1 protease. Characterization of designed heterodimers.
Defective variants of human immunodeficiency virus type 1 (HIV-1) protease (HIV PR) have been engineered to inhibit wild-type (wt) HIV PR activity. These variants were designed to promote the formation of heterodimers and to destabilize the formation of inactive variant homodimers of HIV-1 protease through substitutions at Asp-25, Ile-49, and Gly-50 (Babé, L. M., Rosé, J., and Craik, C. S. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 10069-10073; McPhee, F., Good, A. C., Kuntz, I. D., and Craik, C. S. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 11477-11481). The mechanism of action of these dominant-negative inhibitors was established using recombinantly expressed defective monomers. The defective monomers were refolded in vitro in the presence of wt HIV PR and showed dose-dependent inhibition of proteolytic activity. This inhibition was shown to result from the formation of inactive heterodimers between defective and wt HIV PR monomers. Heterodimer formation was detected by (i) isolating refolded, inactive heterodimers using histidine-tagged defective monomers and (ii) isolating heterodimers from bacteria coexpressing both wt and defective variants of HIV PR. Single-chain variants of HIV PR, in which the C terminus of the wt HIV PR monomer was covalently tethered to the N terminus of the defective monomer, were also expressed and analyzed. Thermal denaturation of these single-chain heterodimers using differential scanning calorimetry revealed a 1.5-7.2 degrees C greater thermal stability than single-chain wt HIV PR. The thermodynamic trend shown by these three variants mirrors their relative inhibition in provirus transfection assays. These data support the model that the effects seen both in tissue culture and in vitro arise from an increase in stability conferred on these heterodimers by interface mutations and identifies heterodimer formation as their mechanism of inhibition.
Dimerization↗
Dubowitz syndrome: a defect in the cholesterol biosynthetic pathway?
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Abnormalities, Multiple↗
Neonatal urinary steroids in Smith-Lemli-Opitz syndrome associated with 7-dehydrocholesterol reductase deficiency.
The biosynthetic abnormality in Smith-Lemli-Opitz syndrome (SLOS) is a deficiency of 7-dehydrocholesterol (7DHC) reductase, the enzyme responsible for catalyzing the final step in the Kandutsch-Russell pathway for cholesterol synthesis. Because the disposition of 7DHC and 8-dehydrocholesterol [8DHC; cholesta-5,8(9)-dien-3beta-ol] produced in this syndrome is little understood, we have analyzed urine from three young infants by gas chromatography/mass spectrometry to characterize its steroid metabolites. All steroid metabolites of adrenal origin found in normal infant urine were also found in urine from the patients with SLOS but in reduced amount. Quantitatively, the major steroids in these SLOS patients were identified by mass spectrometry as homologs of normal neonatal steroids possessing an additional double bond. Generally, two forms of each steroid were present in a similar amount. Because of the markedly increased levels of 7DHC and 8DHC in SLOS, these almost certainly represented the 5,7 and 5,8(9) unsaturated forms of each metabolite. The most abundant steroids were tentatively identified as 3beta,16alpha-dihydroxy-5,7-pregnadien-20-one and 3beta,16alpha-dihydroxy-5,8(9)-pregnadien-20-one, although similar 21-hydroxylated steroids and homologs of 16alpha-hydroxy-DHEA were also found. This study shows that all enzymatic steps used by cholesterol in the DHEA synthetic pathway are also functional for 7DHC and 8DHC.
Gas Chromatography-Mass Spectrometry↗
Orthostatic-mediated hypoperfusion in limb-shaking transient ischemic attack.
In patients with severe carotid stenosis or total occlusion, episodic contralateral motor dysfunction is more likely related to cerebral hypoperfusion than epileptogenic activity. A man with orthostatic-mediated right-sided limb shaking was found to have total left internal carotid artery occlusion. There was prominent reduction of cerebrovascular reserve seen on single photon emission computed tomography (SPECT) performed with and without acetazolomide. During assumption of an upright position transcranial Doppler (TCD) revealed a marked attenuation of the left middle cerebral artery flow pattern not associated with changes during electroencephalographic monitoring, even after administration of acetazolomide. In this man, limb shaking episodes were attributed to hypoperfusion of the contralateral cerebral hemisphere, and not to epileptogenic activity.
Carotid Stenosis↗
Mycoplasma penetrans and other mycoplasmas in urine of human immunodeficiency virus-positive children.
Urine samples from children with human immunodeficiency virus (HIV) infection and healthy controls were examined for mycoplasmas by culture. Standard biochemical assays, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and PCR (16S and 16S-23S spacer rRNA region) were used for identification of isolates. Mycoplasmas were identified from 13 (87%) of 15 HIV-positive patients and 3 (20%) of 15 HIV-negative control patients. The frequency and type of mycoplasma varied with the severity of HIV infection. Mycoplasma penetrans, Mycoplasma pirum, Mycoplasma fermentans, and Mycoplasma genitalium were isolated from patients with severe immunodeficiency. Mycoplasma hominis and Ureaplasma urealyticum were isolated more frequently from children in the early stages of HIV infection and from HIV-negative patients. Mycoplasma penetrans was isolated from one (50%) of two patients in Centers for Disease Control and Prevention (CDC) group B and from five (55.5%) of nine pediatric patients with AIDS (CDC group C). This is the first report that indicates that "AIDS-associated" mycoplasmas are more common in HIV-infected children than in HIV-negative controls.
Acquired Immunodeficiency Syndrome↗
Functional replacement of the mouse E2A gene with a human HEB cDNA.
The mammalian E2A, HEB, and E2-2 genes encode a unique class of basic helix-loop-helix (bHLH) transcription factors that are evolutionarily conserved and essential for embryonic and postnatal development. While the structural and functional similarities among the gene products are well demonstrated, it is not clear why deletion of E2A, but not HEB or E2-2, leads to a complete arrest in B-lymphocyte development. To understand the molecular basis of the functional specificity between E2A and HEB/E2-2 in mammalian development, we generated and tested a panel of E2A knockin mutations including subtle mutations in the E12 and E47 exons and substitution of both E12 and E47 exons with a human HEB cDNA. We find that the alternatively spliced E12 and E47 bHLH proteins of the E2A gene play similar and additive roles in supporting B lymphopoiesis. Further, we find that HEB driven by the endogenous E2A promoter can functionally replace E2A in supporting B-cell commitment and differentiation toward completion. Finally, the postnatal lethality associated with E2A disruption is fully rescued by the addition of HEB. This study suggests that the functional divergence among E12, E47, and HEB in different cell types is partially defined by the context of gene expression.
Alleles↗
New connection method for isolating and disinfecting intraluminal path during peritoneal dialysis solution-exchange procedures.
Microbiological data have been collected on the performance of a new method of isolating and disinfecting the intraluminal path at the connect/disconnect site of a peritoneal dialysis (PD)-exchange pathway. High-temperature moist-heat (HTMH) disinfection is accomplished by a new device that uses microwave energy to heat the solution contained in the pressure-tight inner lumen of PD connector pairs between the transfer-set connector-clamp and the bag-connector break-away seal. An 85 degrees C (S.D. = 2.4 degrees C, n = 10) rise in solution temperature is seen in 12 seconds, thus yielding temperatures under pressure well over 100 degrees C with starting temperatures of 25 degrees C. Connector pairs were prepared by inoculation of a solution suspension containing at least 10(6) colony-forming units (CFU) of a test micro-organism. Approximately 0.4 mL of solution was contained within the mated connector pair. Using standard D-value determination methods, data were obtained for surviving organisms versus five exposure times and a positive control to obtain a population reduction curve. Four micro-organisms (S. epidermidis, P. aeruginosa, C. albicans, and A. niger) recognized to be among the most prevalent or problematic in causing peritonitis were tested. After microwave heating, the treated solution was aseptically withdrawn from the connector pair using a needle and syringe, plated in growth media, and incubated. Population counts of CFUs after incubation were used to establish survival curves. Results showed a tenfold population reduction in less than 3 seconds for all organisms tested. A 30-second cycle time safely achieves a > 10(8) population-reduction for bacteria and yeast organisms, and a > 10(7) population reduction for fungi. One potential benefit of using this new intraluminal disinfection method is that it may help reduce peritonitis resulting from the even more problematic pathogens such as the gram-negative bacteria and fungal organisms.
Bacteria↗
The k43 gene, required for chorion gene amplification and diploid cell chromosome replication, encodes the Drosophila homolog of yeast origin recognition complex subunit 2.
Lethal alleles of the Drosophila k43 gene result in small or missing imaginal discs, greatly reduced mitotic index, and fragmented and abnormally condensed chromosomes. A female-sterile allele of k43 specifically reduces chorion gene amplification in ovarian follicle cells. k43 was cloned by chromosomal walking, and the identification of the k43 gene was confirmed by phenotypic rescue and sequence analysis of mutant alleles. The sequence analyses reveal that the k43 gene encodes the Drosophila homolog of the yeast origin recognition complex subunit 2 (Orc2p), a protein required for replication origin function and transcriptional silencing in yeast. These results suggest an evolutionarily conserved role for Orc2p in eukaryotic chromosomal DNA replication.
Animals↗
Estimation of contact tympanic membrane temperature with a noncontact infrared thermometer.
STUDY OBJECTIVE: To investigate the agreement between contact tympanic membrane (TM) and noncontact infrared ear thermometers in children. METHODS: Twenty-three children (ages .5 to 10 years) undergoing elective tympanostomy tube placement were studied. An assistant used standard technique to record temperature with an infrared ear thermometer before and after TM temperature was obtained with a bead thermistor placed against the anterior-inferior quadrant of the TM. RESULTS: Mean temperatures were not significantly different: initial IR ear, 36.66 degrees +/-.33 degrees C; TM, 36.71 degrees +/- .42 degrees C; final infrared ear, 36.57 degrees +/- .33 degrees C. The mean bias (difference between initial individual IR ear and TM temperatures) of -.05 degrees +/-.29 degrees C and the 95% limits of agreement of +.53 degrees to -.63 degrees C indicate an acceptable confidence (error range within 3.2% of average TM temperature) for use of the initial infrared ear temperature as an estimate of TM temperature. CONCLUSION: The IR ear thermometer provides an accurate estimate of TM temperature in healthy children and may accurately reflect core body temperature.
Child↗
Detecting pediatric nosocomial infections: how do infection control and quality assurance personnel compare?
OBJECTIVE: To compare how well infection control (IC) and quality assurance (QA) personnel in a specialty setting identify the presence, type (nosocomial or community-acquired), and (if nosocomial) site of infection. METHODS: In 1994, we mailed a survey that included 21 pediatric case histories to IC and QA personnel in pediatric settings in the United States (children's hospitals and medical school-affiliated hospitals with pediatric wards of > 30 beds). From the case histories presented, the respondents were asked to determine whether an infection was present and, if so, whether it was nosocomial or community-acquired. If the infection was nosocomial, the respondent was asked to determine the site of the infection (e.g., urinary tract, bloodstream). RESULTS: From the 289 hospitals to which surveys were mailed, 131 respondents (45.3%) completed 212 surveys. Of the 212 returned surveys, 120 (56.6%) were completed by IC personnel and 92 (43.4%) were completed by QA personnel. Among the 183 respondents from acute care pediatric settings, 92.3% of IC personnel (96/104) and 54.4% of QA personnel (43/79) correctly identified at least 75% of the nosocomial infections (n = 14; p < 0.0001). IC and QA personnel were similar in ability to identify community-acquired infection (88/104 vs 70/79, respectively; p = 0.436). IC personnel were significantly more likely than QA personnel to accurately identify the following sites of infection: respiratory tract infection without secondary bloodstream infection, necrotizing enterocolitis, urinary tract infection with and without secondary bloodstream infection, primary bloodstream infection, surgical site infection, gastroenteritis, esophagitis, and clinical sepsis. CONCLUSIONS: Overall, IC personnel were more accurate than QA personnel in determining whether a nosocomial infection was present and in correctly determining most sites of infection. Both IC and QA personnel had difficulty identifying venous infection and respiratory tract infection with secondary bloodstream infection. Both IC and QA personnel could thus benefit from more concise definitions or further training in detection of these sites of nosocomial infections. In addition, QA personnel did not perform overall as well as IC personnel in identifying nosocomial infections and their sites; this finding suggests the need for QA personnel to be provided specific training on detection of nosocomial infections and validation of their ability to do so. Nosocomial infection surveillance should be the responsibility of those trained and proved capable of detecting these infections.
Child↗
Antigen excretion in the urine after pneumococcal vaccination.
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Antigens, Bacterial↗