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Biomedical subjects

P Cregan

Publications and source records attributed to P Cregan.

10 recordsLinked to original sources

Genome organization in dicots: genome duplication in Arabidopsis and synteny between soybean and Arabidopsis.

Synteny between soybean and Arabidopsis was studied by using conceptual translations of DNA sequences from loci that map to soybean linkage groups A2, J, and L. Synteny was found between these linkage groups and all four of the Arabidopsis chromosomes, where GenBank contained enough sequence for synteny to be identified confidently. Soybean linkage group A2 (soyA2) and Arabidopsis chromosome I showed significant synteny over almost their entire lengths, with only 2-3 chromosomal rearrangements required to bring the maps into substantial agreement. Smaller blocks of synteny were identified between soyA2 and Arabidopsis chromosomes IV and V (near the RPP5 and RPP8 genes) and between soyA2 and Arabidopsis chromosomes I and V (near the PhyA and PhyC genes). These subchromosomal syntenic regions were themselves homeologous, suggesting that Arabidopsis has undergone a number of segmental duplications or possibly a complete genome duplication during its evolution. Homologies between the homeologous soybean linkage groups J and L and Arabidopsis chromosomes II and IV also revealed evidence of segmental duplication in Arabidopsis. Further support for this hypothesis was provided by the observation of very close linkage in Arabidopsis of homologs of soybean Vsp27 and Bng181 (three locations) and purple acid phosphatase-like sequences and homologs of soybean A256 (five locations). Simulations show that the synteny and duplications we report are unlikely to have arisen by chance during our analysis of the homology reports.

Acid Phosphatase↗

Expression and genome organization of resistance gene analogs in soybean.

Sequence analysis of cloned plant disease-resistance genes reveals a number of conserved domains. Researchers have used these domains to amplify analogous sequences, resistance gene analogs (RGAs), from soybean and other crops. Many of these RGAs map in close proximity to known resistance genes. While this technique is useful in identifying potential disease resistance loci, identifying the functional resistance gene from a cluster of homologs requires sequence information from outside of these conserved domains. To study RGA expression and to determine the extent of their similarity to other plant resistance genes, two soybean cDNA libraries (root and epicotyl) were screened by hybridization with RGA class-specific probes. cDNAs hybridizing to RGA probes were detected in each library. Two types of cDNAs were identified. One type was full-length and contained several disease-resistance gene (R-gene) signatures. The other type contained several deletions within these signatures. Sequence analyses of the cDNA clones placed them in the Toll-Interleukin-1 receptor, nucleotide binding domain, and leucine-rich repeat family of disease-resistance genes. Using clone-specific primers from within the 3' end of the LRRs, we were able to map two cDNA clones (LM6 and MG13) to a BAC contig that is known to span a cluster of disease-resistance genes.

Amino Acid Sequence↗

Surgery in the information age.

Currently, surgical procedures involve direct data flows of sensation and mechanical output. As information technology progresses, surgery will change to a system of electronic data flows, with technical, ethical, and training implications.

Biomedical Technology↗

Comparison of two BACTEC anaerobic culture media for recovery of anaerobic bacteria.

A selection of 22 anaerobic isolates, originally recovered from sterile body sites or wounds, was cultured in parallel in BACTEC anaerobic NR7A and lytic 37A bottles supplemented with volunteer human blood. The overall detection rate was 95% for the 37A medium and 75% for the NR7A medium (P = 0.003). The growth indices were consistently higher in the 37A bottles, and a positive result occurred sooner in the 37A medium in 11 of the 32 bottles positive in both media. In an analysis of patient specimens, the NR7A bottle had a 14% false-positive rate compared with 3% for the 37A bottle. The increase in recovery, coupled with the decrease in false-positive readings, make the lytic 37A bottle more efficacious than the NR7A bottle as an anaerobic culture medium.

Bacteria, Anaerobic↗

Use of DNA probes to detect Mycobacterium intracellulare and "X" mycobacteria among clinical isolates of Mycobacterium avium complex.

A mycobacterial DNA probe (designated X) was recently developed to help identify Mycobacterium avium complex (MAC) isolates that are nonreactive with probes specific for M. avium or Mycobacterium intracellulare. The prevalence of X probe-positive mycobacteria in clinical specimens and their role in causing disease is unknown. Using a DNA probe kit that includes the X probe, we characterized 100 consecutive clinical MAC isolates as M. avium, M. intracellulare, or X. Lysates from 81 of the isolates reacted with the M. avium probe, 13 with the M. intracellulare probe, 3 with the X probe, and 3 failed to hybridize with any of the probes. All three X-positive isolates were recovered from sputa of patients who were recent immigrants to the United States and who presented with hemoptysis. One isolate was from a Hispanic man infected with human immunodeficiency virus type 1 (HIV-1) and the other 2 were from Filipino patients with no HIV-1 risk factors. This study also showed a higher than expected number of M. intracellulare isolates from blood and cerebrospinal fluid of HIV-1-infected patients.

Acquired Immunodeficiency Syndrome↗

Hemolytic transfusion reaction following transfusion of frozen and washed autologous red cells.

A case of hemolytic transfusion reaction, accompanied by hypotension and followed by transient renal failure, occurred after the transfusion of 1 unit of previously frozen autologous red cells. Subsequent investigation revealed the probable cause of the hemolysis to be inadequate deglycerolization of the unit. The cause of the associated symptoms is unknown. Possibilities include nephrotoxic effects of hemoglobin or stroma, toxic effects of glycerol, or release of vasoactive or thrombogenic substances from lysed red cells. This case of a hemolytic reaction adds to the known risks of autologous transfusion.

Blood Preservation↗

Comparison of four methods for rapid detection of Pneumocystis carinii in respiratory specimens.

Four stains for the detection of Pneumocystis carinii in respiratory specimens were compared for sensitivity, specificity, preparation time, and ease of interpretation. One hundred specimens were collected. Of these, 50 were induced sputum specimens and 50 were bronchoalveolar lavage fluid. All specimens were stained with Diff-Quik (DQ) (a modified Giemsa stain), a quick silver stain, and direct and indirect immunofluorescence stains. A positive specimen was defined as any smear positive by two or more of the methods. Fifty-eight percent of specimens were positive. Seventy-four percent of the sputum specimens and 42% of the bronchoalveolar lavages were positive. The sensitivities for detection of P. carinii in sputum were 92% with silver stain, 97% with direct immunofluorescence assay (DFA), 97% with indirect immunofluorescence assay (IFA), and 92% with DQ. The sensitivities for detection in bronchoalveolar lavage were 86% with silver stain, 90% with DFA, 86% with IFA, and 81% with DQ. Preparation times varied from 90 min for the silver stain and IFA to 3 min for DQ. Costs of the tests varied from $1.50 per slide for DQ to $10.00 per slide for the silver stain and DFA. Reading times varied from 10 to 30 min for the silver stain and DQ to less than 5 min for the immunofluorescence assays. We conclude that all of these tests are viable options for the clinical laboratory, and the choice will be influenced by factors such as clinical volume, ability to batch specimens, and expertise of technological support. A reasonable option may be to use the quick and inexpensive DQ as a screening test and to confirm negative smears with a more sensitive assay.

Bacteriological Techniques↗

Multicystic peritoneal mesothelioma in a 29 year old male.

A case of multicystic peritoneal mesothelioma in a 29 year old white male is reported. This is the second reported case of cystic peritoneal mesothelioma in a male and the first case of cystic mesothelioma reported in Australia. Clinical, histopathologic and ultrastructural findings are discussed together with a review of previous cases.

Adult↗

Congenital duodenal diaphragm in an adult.

A case of congenital duodenal diaphragm has been presented. The clinical features of protracted vomiting, epigastric pain and discomfort after meals with a gastric splash occurring at any age, the biochemical features of profound hypokalaemia and hypochloraemic alkalosis, and the radiological demonstration of a diaphragm have been shown to be of diagnostic significance. The operation of vagotomy and gastroenterostomy was unsuccessful in this case, and a literature review suggests that duodenotomy with excision of the diaphragm is the preferred method of treatment.

Duodenum↗