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Biomedical subjects

D F Gordon

Publications and source records attributed to D F Gordon.

At least 91 records · Page 5Linked to original sources
PubMed1979

Emergency coronary artery revascularization: a possible therapy for acute myocardial infarction.

Cardiac muscle death caused by coronary artery occlusion is a dynamic process that often takes hours or days. Emergency revascularization (saphenous vein bypass graft (SVBG) during acute myocardial infarction (MI) can interrupt myocardial necrosis, salvage ischemic myocardium and revascularize vessels with obstructive lesions not involved in the MI. In this report we describe a preliminary experimental study of 75 patients in which emergency SVBG was the therapy for acute MI. Group 1, 16 patients, required vasoactive medications and/or intraaortic balloon pumping to maintain their blood pressure preoperatively. There was one operative death and two late deaths. Group 2 consisted of 59 hemodynamically stable patients. There were no deaths. The average preop CPK in group 1 was 892 vs 504 in group 2 (p greater than 0.05). Surgical techniques were routine. The average time from the onset of chest pain that continued to surgery was 6.5 hours. Forty patients were restudied. Post- vs presurgical hemodynamics revealed ejection fraction increased by 34% (p greater than 0.05), left ventricular end-diastolic pressure reduced by 40% (p greater than 0.01). End-systolic and end-diastolic volume reduced by 30% (p greater than 0.05), and 15% (p greater than 0.01), and stroke volume improved 25% (p greater than 0.05). Operative mortality was 1.3% and late mortality 2.8%. These results suggest that cautious continued trial of emergency SVBG in patients with evolving MI is warranted.

Acute Disease↗
PubMed1971

Improved isolation of anaerobic bacteria from the gingival crevice area of man.

A roll tube technique (Hungate method) was employed in an attempt to cultivate a maximal portion of the organisms in the gingival crevice area of man. This technique achieves an anaerobic state by flushing the local environment with oxygen-free gas. Once collected, the crevicular debris was immediately placed into sterile oxygen-free test tubes which were flushed out by the oxygen-free gas. In this manner, the samples were weighed, dispersed, diluted, and cultured in roll tubes and plates. The medium for control (Brewer Jar technique) and Hungate techniques was Heart Infusion Agar fortified with 10% defibrinated horse blood. When the Hungate technique was used, the recovery of viable bacteria, as a percentage of the direct microscopic count, was significantly greater than plates incubated aerobically or utilizing the Brewer Anaerobic technique. Cultural counts by using the Hungate method averaged 41.3% for six samples when 90% nitrogen and 10% hydrogen were used, 70.4% for eight samples when 85% nitrogen, 10% hydrogen, and 5% carbon dioxide were used, and 63.4% for eight samples when 100% carbon dioxide was the gaseous atmosphere. At no time were cultural counts, by using anaerobic plates (Brewer Jar), more than 24% of the direct microscopic count. This suggests that exclusion of oxygen and the presence of carbon dioxide maximized recovery of gingival crevice bacteria.

Adult↗
PubMed1967

Reisolation of Staphylococcus salivarius from the human oral cavity.

Twenty-four strains of gram-positive facultative cocci, arranged primarily in small clusters, were isolated from the surface of the human tongue. With the exception of 14 catalase-negative isolates, these strains were identical in cultural and biochemical characteristics and in deoxyribonucleic acid base composition. All cultures produced viscous growth in both liquid and agar media. They fermented glucose anaerobically, reduced nitrate beyond nitrite, were benzidine-positive, and failed to grow in the presence of 5% NaCl or at 45 C. In addition, they exhibited guanine plus cytosine (G + C) contents of 55.4 to 58.3%. These isolates differed from strains of pediococci, aerococci, and micrococci which were included for comparison. On the basis of G + C content, these organisms appear to be intermediate between micrococci and staphylococci; however, on the basis of anaerobic glucose fermentation, it is suggested that they be placed in the genus Staphylococcus. It is proposed that they be recognized as S. salivarius.

Bile Acids and Salts↗
PubMedDate not supplied

Nucleotide sequence of bovine parathyroid hormone messenger RNA.

The sequence of bovine parathyroid hormone mRNA has been determined by sequence analysis of near full-length cloned DNA complementary to the mRNA. Restriction fragments hybridized to the mRNA and extended toward the 5' terminus with reverse transcriptase were analyzed to derive the sequence not present in cDNA. The reverse transcripts were heterogeneous in length with three major stopping points within 8 nucleotides of each other and a minor stop about 30 bases further toward the 5' terminus of the mRNA. The sequence of the gene corresponding to the minor reverse transcript begins with the sequence 5' XXXATATATAAAA which contains the consensus sequence for a TATA box, a putative eukaryotic promoter sequence. Assuming that the major reverse transcriptase stop nearest the 5' terminus of the mRNA, which is 24 bases downstream from the TATA box, represents the beginning of bovine PTH mRNA, the mRNA contains 672 nucleotides, 100 in the 5' noncoding region, 348 in the coding region and 224 in the 3' noncoding region. Bovine PTH mRNA contains 38% G and C bases. The 3' noncoding region is particularly rich in A and U bases with the last 100 nucleotides of the molecules containing 46% U and 32% A. As with other mRNAs, the sequences CG and UAG occur much less than expected. The 5' noncoding region does not contain an AUG before the initiator codon and contains two potential regions that could base-pair with sequences near the 3' terminus of 18S ribosomal RNA. The sequence AAUAAA is present 14 nucleotides from the polyadenylic acid at the 3' terminus. Bovine PTH mRNA exhibits extensive homology with human PTH mRNA.

Animals↗
PubMedDate not supplied

Organization and nucleotide sequence of the gene encoding the beta-subunit of murine thyrotropin.

We constructed a murine genomic DNA library in lambda EMBL3 and have isolated and determined the nucleotide sequence of the murine thyrotropin beta-subunit (TSH beta) gene. The cloned gene was derived from a thyrotropic tumor and had no detectable rearrangements when compared to the murine TSH beta gene in total genomic DNA. The murine TSH beta gene is 5 kb in size and consists of five exons and four introns. The 5' untranslated region of the mRNA is encoded except for a single nucleotide by exons 1, 2, and 3. The protein-coding regions are encoded by exons 4 and 5 while the 3' untranslated region is entirely contained in exon 5. Primer extension analysis using an exon 1-specific primer was used to map the 5' end of the gene. Two transcriptional start sites are present in the murine TSH beta gene which appear to be positioned by two TATAAA sequences located 40 bp apart. In all, 99% of transcripts initiate at the downstream site. Transcription from both start sites is affected by thyroidal status in both murine pituitaries and in TtT97 thyrotropic tumors. Finally, sequences homologous with putative thyroid-responsive elements and cyclic AMP-responsive elements are present in the 5'-flanking region and may be important in regulating negative and positive effects on TSH beta gene expression.

Amino Acid Sequence↗