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Biomedical subjects

J F Ryan

Publications and source records attributed to J F Ryan.

At least 19 recordsLinked to original sources
PubMed2000

The homeodomain resource: a prototype database for a large protein family.

The Homeodomain Resource is an annotated collection of non-redundant protein sequences, three-dimensional structures and genomic information for the homeodomain protein family. Release 2.0 contains 765 full-length homeodomain-containing sequences, 29 experimentally derived structures and 116 homeobox loci implicated in human genetic disorders. Entries are fully hyperlinked to facilitate easy retrieval of the original records from source databases. A simple search engine with a graphical user interface is provided to query the component databases and assemble customized data sets. A new feature for this release is the addition of more automated methods for database searching, maintenance and implementation of efficient data management. The Homeodomain Resource is freely available through the WWW at http://genome.nhgri.nih.gov/homeodomain

Amino Acid Sequence↗
PubMed2000

The breast cancer information core: database design, structure, and scope.

The Breast Cancer Information Core (BIC) is an open access, on-line mutation database for breast cancer susceptibility genes. In addition to creating a catalogue of all mutations and polymorphisms in breast cancer susceptibility genes, a principle aim of the BIC is to facilitate the detection and characterization of these genes by providing technical support in the form of mutation detection protocols, primer sequences, and reagent access. Additional information at the site includes a literature review compiled from published studies, links to other internet-based, breast cancer information and research resources, and an interactive discussion forum which enables investigators to post or respond to questions and/or comments on a bulletin board. Hum Mutat 16:123-131, 2000. Published 2000 Wiley-Liss, Inc.

Algorithms↗
PubMed2000

Comparative genome mapping in the sequence-based era: early experience with human chromosome 7.

The success of the ongoing Human Genome Project has resulted in accelerated plans for completing the human genome sequence and the earlier-than-anticipated initiation of efforts to sequence the mouse genome. As a complement to these efforts, we are utilizing the available human sequence to refine human-mouse comparative maps and to assemble sequence-ready mouse physical maps. Here we describe how the first glimpses of genomic sequence from human chromosome 7 are directly facilitating these activities. Specifically, we are actively enhancing the available human-mouse comparative map by analyzing human chromosome 7 sequence for the presence of orthologs of mapped mouse genes. Such orthologs can then be precisely positioned relative to mapped human STSs and other genes. The chromosome 7 sequence generated to date has allowed us to more than double the number of genes that can be placed on the comparative map. The latter effort reveals that human chromosome 7 is represented by at least 20 orthologous segments of DNA in the mouse genome. A second component of our program involves systematically analyzing the evolving human chromosome 7 sequence for the presence of matching mouse genes and expressed-sequence tags (ESTs). Mouse-specific hybridization probes are designed from such sequences and used to screen a mouse bacterial artificial chromosome (BAC) library, with the resulting data used to assemble BAC contigs based on probe-content data. Nascent contigs are then expanded using probes derived from newly generated BAC-end sequences. This approach produces BAC-based sequence-ready maps that are known to contain a gene(s) and are homologous to segments of the human genome for which sequence is already available. Our ongoing efforts have thus far resulted in the isolation and mapping of >3,800 mouse BACs, which have been assembled into >100 contigs. These contigs include >250 genes and represent approximately 40% of the mouse genome that is homologous to human chromosome 7. Together, these approaches illustrate how the availability of genomic sequence directly facilitates studies in comparative genomics and genome evolution.

Animals↗
PubMed1999

Informatic selection of a neural crest-melanocyte cDNA set for microarray analysis.

With cDNA microarrays, it is now possible to compare the expression of many genes simultaneously. To maximize the likelihood of finding genes whose expression is altered under the experimental conditions, it would be advantageous to be able to select clones for tissue-appropriate cDNA sets. We have taken advantage of the extensive sequence information in the dbEST expressed sequence tag (EST) database to identify a neural crest-derived melanocyte cDNA set for microarray analysis. Analysis of characterized genes with dbEST identified one library that contained ESTs representing 21 neural crest-expressed genes (library 198). The distribution of the ESTs corresponding to these genes was biased toward being derived from library 198. This is in contrast to the EST distribution profile for a set of control genes, characterized to be more ubiquitously expressed in multiple tissues (P < 1 x 10(-9)). From library 198, a subset of 852 clustered ESTs were selected that have a library distribution profile similar to that of the 21 neural crest-expressed genes. Microarray analysis demonstrated the majority of the neural crest-selected 852 ESTs (Mel1 array) were differentially expressed in melanoma cell lines compared with a non-neural crest kidney epithelial cell line (P < 1 x 10(-8)). This was not observed with an array of 1,238 ESTs that was selected without library origin bias (P = 0.204). This study presents an approach for selecting tissue-appropriate cDNAs that can be used to examine the expression profiles of developmental processes and diseases.

Calibration↗
PubMed1999

The Homeodomain Resource: sequences, structures and genomic information.

The Homeodomain Resource is a comprehensive collection of sequence, structure and genomic information on the homeodomain protein family. Available through the Resource are both full-length and domain-only sequence data, as well as X-ray and NMR structural data for proteins and protein-DNA complexes. Also available is information on human genetic diseases and disorders in which proteins from the homeodomain family play an important role; genomic information includes relevant gene symbols, cytogenetic map locations, and specific mutation data. Search engines are provided to allow users to easily query the component databases and assemble specialized data sets. The Homeodomain Resource is available through the World Wide Web at http://genome.nhgri.nih.gov/homeodomain

Animals↗
PubMed1999

Spatio-temporal contrast sensitivity, coherent motion, and visible persistence in developmental dyslexia.

Three experiments measured spatio-temporal contrast sensitivity, coherent motion, and visible persistence in a single group of children with developmental dyslexia and a matched control group. The findings were consistent with a transient channel disorder in the dyslexic group which showed a reduction in contrast sensitivity at low spatial frequencies, a significant reduction in sensitivity for coherent motion, and a significantly longer duration of visible persistence. The results were also examined by classifying the dyslexic group into dyseidetic, dysphonetic, and mixed (dysphoneidetic) subgroups. There were no differences between the control and dyseidetic groups in contrast sensitivity, in coherent motion and in visible persistence. In comparison to the control group, the mixed (dysphoneidetic) dyslexic subgroup was found to have a significant reduction in contrast sensitivity at low spatial frequencies, a significant reduction in sensitivity for coherent motion, and a significantly longer duration of visible persistence. In comparison to the control group, the dysphonetic group only showed a reduction in contrast sensitivity at low spatial frequencies. Comparisons between the dyseidetic, dysphonetic and mixed dyslexic subgroups showed that there were no substantive differences in contrast sensitivity, coherent motion, and visible persistence. The results support the proposal and findings by Borsting et al. (Borsting E, Ridder WH, Dudeck K, Kelley C, Matsui L, Motoyama J. Vis Res 1996;36:1047-1053) that a transient channel disorder may only be present in a dysphoneidetic dyslexic subgroup. Psychometric assessment revealed that all the children with dyslexia appear to have a concurrent disorder in phonological coding, temporal order processing, and short-term memory.

Adolescent↗
PubMed1999

WebBLAST 2.0: an integrated solution for organizing and analyzing sequence data.

SUMMARY: WebBLAST is a suite of programs intended to assist in organizing sequencing data and to provide first-pass sequence analysis in an automated fashion. Data processing is fully automated, with end-users being presented both graphical and tabular summaries of data that can be viewed using any Web browser. AVAILABILITY: The program is free and available at http://genome.nhgri.nih. gov/webblast.

Base Sequence↗
PubMed1997

Sudden unexplained death in a patient with a family history of malignant hyperthermia.

A 23-year-old healthy white male in excellent physical condition developed cardiac arrest and rigidity during moderate exercise. He had a strong family history of malignant hyperthermia (MH). Two hours postmortem, his temperature was noted to be markedly elevated [41 degrees C (106 degrees F)]. A review of the possible differential diagnoses point to MH as a reasonable etiology.

Adult↗
PubMed1994

Myoplasmic calcium changes precede metabolic and clinical signs of porcine malignant hyperthermia.

This study examines the chronologic relationship of the biochemical and clinical development of malignant hyperthermia (MH) in susceptible swine. Four pigs previously established by challenge to be susceptible to MH were studied. Monitors included end-tidal CO2 (ETCO2), transcutaneous oxygen saturation (Spo2), intraarterial blood pressure, rectal temperature, electrocardiogram (ECG), and train-of-four twitch measurements. Calcium-selective microelectrodes were used to monitor changes in the concentration of free myoplasmic calcium ([Ca2+]i). The animals were studied in the resting state, during the development of the syndrome, and after treatment with dantrolene sodium. The increase in [Ca2+]i preceded the increase in ETCO2 that preceded a decrease in Spo2 that preceded the classic first sign, tachycardia, and all preceded the increase in rectal temperature. Dantrolene reversed all of these physiologic changes in the same order of precedence as the increase.

Animals↗
PubMed1993

Fatal facial ulceration.

A case of an elderly man with a large facial ulcer is reported. The diagnosis of Wegener's granulomatosis was made at post-mortem when evidence of a granulomatous vasculitis was found in both the skin and lungs. This case serves to illustrate the difficulty in making the diagnosis of Wegener's granulomatosis, especially when it presents in its 'limited' form.

Aged↗
PubMed1992

EU 4093 decreases intracellular [Ca2+] in skeletal muscle fibers from control and malignant hyperthermia-susceptible swine.

The mechanisms causing the malignant hyperthermia (MH) syndrome are related to a malfunction of intracellular Ca2+ homeostasis and can be prevented or reversed by dantrolene. EU 4093 (Azumolene, 1-[[[5-(4-bromophenyl)-2-oxyzolyl] methylene]amino]-2-4- imidazolidinedione) is a 30-fold more water-soluble analogue of dantrolene that is believed to have the same effects as dantrolene on the intracellular free Ca2+ concentration [( Ca2+]i) in skeletal muscle and that should have similar efficacy in treating and preventing the clinical manifestations of MH in response to a halothane/succinylcholine challenge. To test this hypothesis, experiments were carried out in four controls (Yorkshire) and eight MH-susceptible crossbreed swine (Poland China X Pietrain). The resting [Ca2+]i in normal muscle fibers measured by Ca(2+)-selective microelectrodes was 111 +/- 12 nM (mean +/- standard deviation, n = 30), whereas in the MH muscles the resting [Ca2+]i was 395 +/- 36 nM, (n = 28) (P = 0.0001). EU 4093 decreased [Ca2+]i in MH-susceptible skeletal muscle in a dose-related fashion from 207 to 38 nM after 0.5 to 2.0 mg/kg, respectively, and had a similar effect in control skeletal muscle (58 to 30 nM) after the same doses. In MH-susceptible swine, a dose of 2.0 mg/kg was successful in preventing any clinical signs of the MH syndrome during a subsequent halothane/succinylcholine challenge. A dose of 0.5 mg/kg was able to attenuate but not reverse the clinical signs of the MH syndrome after a halothane challenge, whereas a dose of 1.0 mg/kg was completely successful in reversing this effect in all subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

A single-blind study of combined pulse oximetry and capnography in children.

This single-blind study examined four levels of monitoring in 402 pediatric cases. Patients were randomly assigned to one of four groups: 1) oximeter and capnograph; 2) only oximeter; 3) only capnograph; or 4) neither oximeter nor capnograph data available to the anesthesia team. An anesthesiologist, not involved in patient care, observed all cases and continuously recorded hemoglobin oxygen saturation (Spo2), ECG, expired CO2, and the oximeter plethysmographic output. Mean age, weight, ASA physical status, airway management (mask or endotracheal tube), and anesthetic technique were similar in each group. Two-hundred sixty problems were documented in 153 patients. Fifty-nine events in 43 patients resulted in "major" desaturation (Spo2 less than or equal to 85% for greater than or equal to 30 s). Fifteen "major" capnograph events (esophageal intubation, disconnection, accidental extubation, or obstructed endotracheal tube) were observed in 11 patients; 8 of these also developed varying degrees of desaturation. One-hundred thirty "minor" desaturation events (Spo2 less than or equal to 95% for greater than 60 s) and 79 "minor" desaturation events (hypercarbaria or hypocarbia) were observed. A number of problems fulfilled criteria in multiple categories. Infants less than or equal to 6 months of age had the highest incidence of major desaturation events (18 of 65 [27%]) compared to toddlers 7-24 months of age or children greater than 24 months of age (P less than 0.001). Blinding the oximeter data increased the number of patients (12 vs. 31) experiencing major desaturation events (P = 0.003); blinding the capnograph data altered neither the frequency of desaturation events nor the incidence of major capnograph events.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1990

The effects of extracellular magnesium on myoplasmic [Ca2+] in malignant hyperthermia susceptible swine.

It is now well established that the pathophysiology of the malignant hyperthermia (MH) syndrome is related to a malfunction of intracellular calcium homeostasis. Magnesium plays important roles in the basic contractile properties of muscle, and many of its actions are antagonistic to those of calcium. The aim of this study was to determine the effectiveness of magnesium sulphate to prevent the MH episode in susceptible animals and correlate this with its effects on the intracellular free calcium [( Ca2+]i). The experiments were carried out using six control (Yorkshire) and ten MH-susceptible crossbred swine (Poland China X Pietrain). After determination of resting concentrations of [Ca2+]i and [Mg2+]i, each animal was given either two iv bolus doses of 50 mg/kg or one iv bolus of 100 mg/kg of MgSO4. The resting [Ca2+]i and [Mg2+]i were determined by means of ion-selective microelectrodes. The resting [Ca2+]i in normal muscle fibers was 0.11 +/- 0.01 microM (mean +/- SEM), whereas in the MH muscles the resting [Ca2+]i was 0.36 +/- 0.01 microM. In neither group was the resting [Ca2+]i modified by MgSO4. This cumulative dose of MgSO4 (100 mg/kg) was not able to prevent the induction of an MH episode by 2% halothane. Although MgSO4 did not directly decrease [Ca2+]i, it did attenuate the increase in [Ca2+]i associated with the syndrome from 7.29 +/- 0.43 microM in untreated animals to 0.84 +/- 0.03 microM in MgSO4 pretreated swine. In addition, the limb rigidity that accompanies this increase in calcium was prevented by MgSO4 pretreatment. Baseline measurements of [Mg2+]i were not different in control and MH-susceptible muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Parosteal osteogenic sarcoma of the hand.

Osteosarcomas of the tubular bones of the hands and feet are rare tumours and the initial biopsies are frequently misdiagnosed. We report a case of parosteal osteosarcoma arising in the metacarpal of a female patient aged 53 at first presentation. The tumour recurred three times over two decades and eventually metastasized to the lungs. The differential diagnosis includes florid reactive mesenchymal proliferation and bizarre parosteal osteochondromatous proliferations of the tubular bones of the hand.

Bone Neoplasms↗