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Biomedical subjects

M Sullivan

Publications and source records attributed to M Sullivan.

At least 379 records · Page 21Linked to original sources
PubMed1984

The reproducibility of hemodynamic, electrocardiographic, and gas exchange data during treadmill exercise in patients with stable angina pectoris.

Fourteen male patients with exercise test-induced angina and ST-segment depression underwent treadmill testing on three consecutive days to evaluate the reproducibility of certain treadmill variables. Computerized ST-segment analysis and expired gas analysis, including anaerobic threshold, were evaluated for reproducibility using an intra-class correlation coefficient analysis. Measured oxygen uptake at peak exercise displayed better reproducibility than total treadmill time, the onset of angina, and the gas exchange anaerobic threshold (ATGE). The double product, heart rate, and ST-segment displacement in lead X were found to be reproducible at peak exercise, the onset of angina, and the ATGE. The incorporation of gas exchange analysis can provide accurate physiologic determinants of exercise capacity in patients with angina pectoris. In addition, noninvasive estimates of myocardial oxygen demand and ischemia can be reproducibly determined. These findings have important implications for the design of studies evaluating the effects of an intervention on angina pectoris.

Adult↗
PubMed1983

Role of myocardial ischemia in the genesis of stress-induced S-T segment elevation in previous anterior myocardial infarction.

This study tests the hypothesis that myocardial ischemia is responsible for exercise-induced S-T segment elevation in patients with previous anterior myocardial infarction (MI). Exercise stress testing in conjunction with thallium imaging of the myocardium was performed in 28 patients with previously documented anterior MI. Thallium images were analyzed by computer for the presence of initial uptake defects and evidence of abnormal clearance of the isotope from the myocardium (that is, imaging evidence of ischemia). Total S-T segment elevation (sigma ST) in precordial leads V1 to V6 at rest was subtracted from sigma ST at peak stress in order to quantitate the extent of S-T elevation induced by stress (delta ST). Two groups of patients were identified; 1 with stress-induced S-T elevation (Group I, delta ST greater than or equal to 4.0 mm) and 1 without this abnormality (Group II, delta ST less than 4.0 mm). Evidence of abnormal thallium washout from myocardial scan segments occurred in 12 of 15 Group I patients versus 9 of 13 Group II patients (difference not significant). In addition, abnormal tracer washout from anterolateral or septal scan segments occurred in 5 patients in each group. Likewise, abnormal thallium clearance from inferior or posterior scan segments occurred in 8 of 15 Group I patients versus 7 of 13 Group II patients (difference not significant). The patient with the greatest amount of stress-induced S-T elevation (S-T 11.5 mm) had no evidence of ischemia during the stress test. However, Group I patients did have larger anterolateral plus septal initial thallium uptake defect scores than did those of Group II (10 of 15 with defect score greater than or equal to 350 in Group I versus 1 of 13 in Group II, p less than 0.002). Similarly, resting left ventricular ejection fraction greater than or equal to 30% was present in only 4 of 15 Group I patients versus 13 of 13 in Group II (p less than 0.001). Finally, multiple stepwise linear regression analysis demonstrated that delta ST correlated best with the extent of initial anterolateral plus septal thallium uptake defect score (F = 17.3, p less than 0.001) and to a lesser extent with resting ejection fraction (F = 5.2, p less than 0.05) and change in heart rate from rest to peak stress (F = 8.1, p less than 0.01; corrected multiple correlation coefficient = 0.76, p less than 0.001). Thus, in patients with previous anterior MI (1) exercise-induced myocardial ischemia occurs as often with as without S-T segment elevation, (2) myocardial ischemia is not required for the production of stress-induced S-T segment elevation, and (3) stress-induced S-T elevation primarily reflects the extent of previous anterior wall damage and to a lesser extent an increase in heart rate between rest and peak stress.

Adult↗
PubMed1983

Isolation and characterization of a genomic clone encoding chick alpha 1 type III collagen.

We have isolated a cloned segment of the chick alpha 1 type III collagen gene from a genomic DNA library. This DNA clone was obtained by cross-hybridization with a cDNA clone containing sequences coding for a segment of the carboxy propeptide of chick alpha 1 type I collagen. This genomic clone was identified as coding for alpha 1 type III collagen by DNA sequence analysis of two segments of the gene and by its ability to hybridize to crop mRNA but not to calvaria mRNA in agreement with the presence of alpha 1 type III collagen in crop but not in calvaria. The deduced amino acid sequences reveal characteristic features for alpha 1 type III collagen and are in good agreement with the known protein sequences of calf and human alpha 1 type III collagen. The size of alpha 1 type III mRNA is about 6 kilobases, slightly larger than the mRNA for alpha 1 type I. R-loop electron microscopic analysis indicates that at least 16 exons are interspersed in a 9-kilobase DNA segment that contains the third distal part of the alpha 1 type III collagen gene.

Amino Acid Sequence↗
PubMed1983

Geometric properties of equine metacarpi.

Paired equine metacarpals were harvested, cleaned and sectioned transversely every 20 mm, and the bone geometry analyzed with a computer program. The cross-sectional area is largest in the middle third of the bone, and tapers off at either end. The principal axes are typically within 15 degrees of the anatomical axis, with the distal end rotated internally relative to the proximal end. At midshafts the bending stiffness in the antero-posterior plane is about 2/3 of the stiffness in the medio-lateral plane. The torsional stiffness is highest proximally. The equine third metacarpal appears to be designed to resist axial compression and mediolateral bending very well, and exhibits uniform resistance to torsion along its length.

Animals↗
PubMed1983

Electron microscope heteroduplex mapping of naphthalene oxidation genes on the NAH7 and SAL1 plasmids.

Introduction of the transposon Tn5 to serve as a marker allows electron microscope heteroduplex mapping of the naphthalene oxidation genes on the approximately 83-kb NAH7 and the related approximately 85-kb SAL1 plasmids. The electron microscope-mapped gene positions on the NAH7 plasmid are in close agreement with those mapped previously by restriction digestion. The SAL1 plasmid can be considered as a mutant NAH7 plasmid which fails to direct the conversion of naphthalene to salicylate because of a mutational block but retains intact coding sequences for salicylate oxidation. Analysis of heteroduplex molecules formed between the SAL1 and NAH7::Tn5 EcoRI fragments and the known NAH7/SAL1 homology strongly suggest that the SAL1 DNA is completely homologous to NAH7 DNA except that a approximately 2.5-kb DNA segment constituting most of the nahA gene is replaced by approximately 4.6-kb nonhomologous DNA.

Chromosome Mapping↗
PubMed1983

Isolation of genomic DNA clones spanning the entire fibronectin gene.

Overlapping recombinant clones that appear to encompass the entire fibronectin gene have been isolated by step-wise screening of a library of chicken genomic DNA fragments. The first genomic clone was isolated by using a cloned fibronectin cDNA hybridization probe. The remaining clones were obtained by using defined fragments of this and successive genomic clones as probes. Their relationships and overlaps were determined by electron microscopy, restriction mapping, and heteroduplex analysis. Based on electron microscopic analysis of hybrids between these clones and fibronectin mRNA, the gene is approximately 48 kilobases long, more than 5 times larger than the corresponding mRNA. This large gene contains at least 48 exons interrupted by introns of highly variable size. The total exon size as estimated by R-loop analysis is 8 kilobases, similar to the mRNA for fibronectin. With the exception of the 3'- and 5'-terminal exons, the exons are small and roughly similar in size. The average exon size is 147 +/- 37 base pairs, corresponding to a protein unit of 50 amino acids. The nucleotide sequence of one of these exons was determined. The deduced amino acid sequence has marked homologies with one type of repetitive protein sequence unit known to exist in bovine fibronectin. These results suggest that the gene for fibronectin may have arisen by multiple gene duplications of a primordial gene or genes approximately equal to 150 base pairs long.

Amino Acid Sequence↗
PubMed1983

Variations in the pattern of muscle innervation by the L5 and S1 nerve roots.

Evidence based on electrical studies is presented for the standard and anomalous patterns of innervation of muscles supplied by the fifth lumbar and first sacral nerve roots. Although considerable controversy still exists, previous work in this field suggests that the L5 nerve root supplies tibialis anterior, extensor hallucis longus, extensor digitorum brevis, and the lateral head of gastrocnemius, while the S1 nerve root innervates the medial head of gastrocnemius, soleus, and abductor hallucis. In order to confirm the reliability of this data, the L5 and S1 nerve roots of 50 patients were electrically stimulated during surgery, and distally evoked responses in the relevant muscles were recorded, using surface electrodes. The results confirm the essential reliability of the proposed table of segmental innervation and also demonstrate that most muscles have a dual innervation, with one nerve root being dominant. However, eight patients (16%) exhibited a marked departure from the normal pattern. For example, it is clear that on occasion the extensor digitorum brevis and the lateral head of gastrocnemius can be supplied by S1 and the soleus and medial head of gastrocnemius can be supplied by L5. In a prospective study of 100 patients presenting with clinical evidence of lumbosacral nerve root entrapment, the level of nerve root involvement, as predicted by electromyography, was compared with the operative findings. Correct preoperative nerve root localization was achieved in 84%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

The pediatric early elementary examination: studies of a neurodevelopmental examination for 7- to 9-year-old children.

The Pediatric Early Elementary Examination (PEEX) is a neurodevelopmental assessment designed to evaluate children with learning problems between the ages of 7 and 9. The current study of this procedure focused on a sample of youngsters from two middle-class communities and a group of children referred for learning problems to the School Function Program, a specialty clinic at The Children's Hospital in Boston. During prior pilot testing, diagnostic criteria had been established for specific areas of development assessed on the Pediatric Early Elementary Examination. Findings were expressed as "areas of concern" or developmental weaknesses suggesting the need for further monitoring or referral. It was found that nearly half of the children in the community had at least one such finding. These areas of concern were spread fairly evenly over the seven developmental areas of concern correlated with results of the revised Wechsler Intelligence Scale for Children (WISC-R) and the California Achievement Test in the community. Youngsters referred to the School Function Program with learning problems also were more likely to have multiple areas of developmental concern. Results suggest that the Pediatric Early Elementary Examination shows promise as a reliable and valid system of observation for use by health care professionals.

Achievement↗
PubMed1983

Orthoptics.

Explore the source record for details and available documents.

Adult↗
PubMed1982

Factors affecting absorption of non-steroidal anti-inflammatory agents in the horse.

The absorption of orally administered phenylbutazone (5 mg/kg) was studied in 10 thoroughbreds, eight ponies and four pony foals. Large variations in area under the curve (AUC) and peak plasma concentrations were found both within an animal and within groups of animals. Administration of phenylbutazone (5 mg/kg) following an overnight fast resulted in no difference among the three groups of animals with respect to AUC (0 to 24 hours), mean (+/- sd) values of which were 132 +/- 68, 107 +/- 48 and 98 +/- 6, respectively. Absorption characteristics of two oral phenylbutazone preparations (Equipalazone; Arnolds and Prodynam; Leo Laboratories) (5 mg/kg) given after an overnight fast were similar. Feeding before drug administration decreased AUC and peak plasma concentration and extended the range of the time taken to attain the latter. Repeated twice daily administration of phenylbutazone (5 mg/kg) resulted in more rapid absorption following the morning than the afternoon dose. Investigations with meclofenamic acid (4.4 mg/kg) also resulted in highest peak plasma concentrations and AUC following overnight fast. It was found that absorption was slower with intramuscular injections of phenylbutazone (2.5 mg/kg) than after oral administration in the fasted animal.

Administration, Oral↗