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Biomedical subjects

R M Kay

Publications and source records attributed to R M Kay.

At least 91 records · Page 5Linked to original sources
PubMed1975

Lactate dehydrogenase isozymes of salmonid fish. Evidence for unique and rapid functional divergence of duplicated H-4 lactate dehydrogenases.

Salmonid fish, as a result of total genome duplication, have two genes, Ldh H and Ldh H', coding for polypeptides H and H', respectively, both of which have been shown in their tetrameric forms to be immunologically related to the classical H-4 lactate dehydrogenase isozyme of higher vertebrates (Bailey, G. S., and Wilson, A. C. (1968) J. Biol. Chem. 243,5843). The H-4 and H'-4 isozymes have now been highly purified from quinnat salmon, and their chemical, physical, immunological, and catalytic properties examined, and compared to the M-4 isozyme of salmon. The two proteins H-4 and H'-4 are shown to be very similar in amino acid composition, but significant differences in a few residues suggest differences in amino acid sequences. This suggestion was born out by quantitative immunological experiments in which the H-4 and H'-4 isozymes were shown to be about as different from each other as are the H-4 lactate dehydrogenases of chicken and duck. This suggests that the gene duplication event in salmon which give rise to two Ldh H genes occurred approximately 80 to 100 million years ago. The H'-4 lactate dehydrogenase which has risen from this duplication in salmon is shown to be somewhat intermediate between H-4 and M-4 in thermal stability, and in all catalytic properties examined, including substrate optima, Michaelis constants, and susceptibility to inhibition by high levels of substrate. In particular the H'-4 isozyme is almost exactly intermediate between H-4 and M-4 in its resistance to product inhibition by lactate, the catalytic parameter suggested to be of major functional importance to M-4 lactate dehydrogenase isozymes (Stambaugh, R., and Post D. (1966) J. Biol. Chem. 241,1462). Further, tissue distribution of these isozymes in salmon and trout are shown to be unusual. The M-4 isozyme salmon and trout are shown to be unusual. The M-4 isozyme occurs in very few tissues in detectable levels. It is the H-4 and H'-4 rather than H-4 and M-4, which occur in independently variable but significant levels in most tissues examined. Thus the H'-4 isozyme, despite its very close structural similarity to H-4 appears to possess functional properties which are different from either H-4 or M-4 in salmon, and some properties are midway between the two. This finding, together with the unusual tissue distribution of these isozymes, suggests that salmon with H'-4 lactate dehydrogenase is evolving to function catalytically in the absence of a balanced H-4-M-4 isozyme complement in most tissues. This balance seems to be met in most tissues by combinations of H-4 and H'-4,

Amino Acids↗
PubMedDate not supplied

Variability in the assessment of acetabular index.

This study was undertaken to assess the inter- and intraobserver variability associated with the assessment of acetabular index. Five readers (three senior orthopaedic residents and two pediatric orthopaedic attendings) read each of 24 films on three separate occasions (360 total readings). An independent observer who was blinded to the results of the study assessed whether the radiographs would result in a reproducible acetabular index. Variability was increased for the radiographs that were deemed poorly reproducible by the independent observer. Interobserver variability exceeded intraobserver variability. Variability was comparable for senior orthopaedic residents and attending pediatric orthopaedic surgeons. Even in the group with the least variability (intraobserver variability for reproducible radiographs), the 95% tolerance interval was 8.35 degrees. The results of this study cast doubt on the reliability of the acetabular index based on a single reading.

Acetabulum↗
PubMedDate not supplied

The effect of femoral rotation on the projected femoral neck-shaft angle.

Femoral neck-shaft angle (NSA) was measured in a series of anteroposterior (AP) hip radiographs of a cadaveric femur in varying degrees of rotation. A mathematical model was developed to predict NSA on an AP radiograph in varying degrees of femoral rotation. The predictions of the model were found to correlate well with the experimental data (correlation coefficient = 0.94). Based on the mathematical model, a wide range of patient positioning was found to result in a <10 degrees error in the measurement of femoral NSA. Coxa vara, increased femoral anteversion, cerebral palsy, and developmental dislocation of the hip resulted in a more restricted range of acceptable femoral positioning. External rotation of the femur should be avoided during patient positioning because as little as 7 degrees can cause a > 10 degrees change in the apparent NSA. For all patient populations, internally rotating the femur will allow for determination of the femoral NSA to within 10 degrees .

Adult↗
PubMedDate not supplied

Variability in gait analysis interpretation.

The purpose of this study was to assess the reliability of interpretation of gait analysis data between physicians and institutions. Gait analysis data from seven patients were reviewed by 12 experienced gait laboratory physicians from six institutions. Reviewers identified problems and made treatment recommendations based on the data provided. Agreement among physicians for the most commonly diagnosed problems was slight to moderate (kappa range, 0.14-0.46). Physicians agreed on identification of soft tissue more than bony problems (intraclass correlation, 0.56 vs. 0.37). Variability regarding surgical recommendations for soft-tissue procedures (kappa range, 0.20-0.64) was similar to that for diagnosis of both soft-tissue and bone problems, although recommendation for hamstring lengthening showed substantial agreement (kappa = 0.64). There was less agreement in recommendation of osteotomies (kappa range, 0.13-0.22). Physicians agreed more on the number of soft-tissue procedures than bone procedures recommended (intraclass correlation, 0.65 vs. 0.19). There was an interinstitutional difference in the frequency of soft-tissue (p = 0.0152) and osseous problem identification (p = 0.0002), as well as in the frequency of recommendations for soft-tissue surgery (p = 0.0004) and osteotomies (p < 0.0001). Although gait analysis data are themselves objective, this study demonstrates some subjectivity in their interpretation. The interobserver variability reported here is similar to that reported for established classification systems of various orthopedic conditions.

Adolescent↗
PubMedDate not supplied

Effects of low level dosing of iron on the haematology and growth rate of piglets.

Of 472 piglets (56 litters), half reeived 200 mg and half received 100 mg of iron as iron dextran administered intramuscularly as a single dose into the ham muscles between the first and fourth day after birth. The piglets were weaned at about three weeks of age, at which time those given 200 mg of iron had higher values of all haematological components. However, there was no significant difference between the mean daily live-weight gains of the two groups, and 100 mg iron maintained haematological components above levels associated with anaemia. It is suggested that 100 mg iron as iron dextran is adequate for piglets weaned at three weeks of age.

Animals↗
PubMedDate not supplied

Pediatric ankle fractures: evaluation and treatment.

Pediatric ankle fractures account for approximately 5% of pediatric fractures and 15% of physeal injuries. The biomechanical differences between mature and immature bones, as well as the differing forces applied to those bones, help explain the differences between adult and pediatric fractures. The potential complications associated with pediatric ankle fractures include those seen with adult fractures (such as posttraumatic arthritis, stiffness, and reflex sympathetic dystrophy) as well as those that result from physeal damage (including leg-length discrepancy, angular deformity, or a combination thereof). The goals of treatment are to achieve and maintain a satisfactory reduction and to avoid physeal arrest. A knowledge of common pediatric ankle fracture patterns and the pitfalls associated with their evaluation and treatment will aid the clinician in the effective management of these injuries.

Adolescent↗
PubMedDate not supplied

Pediatric foot fractures: evaluation and treatment.

Foot fractures account for 5% to 8% of all pediatric fractures and for approximately 7% of all physeal fractures. A thorough understanding of the anatomy of the child's foot is of central importance when treating these injuries. Due to the difficulties that may be encountered in obtaining an accurate physical examination of a child with a foot injury and the complexities of radiographic evaluation of the immature foot, a high index of suspicion for the presence of a fracture facilitates early and accurate diagnosis. Although the treatment results in pediatric foot trauma are generally good, potential pitfalls in the treatment of Lisfranc fractures, talar neck and body fractures, and lawn mower injuries to the foot must be anticipated and avoided if possible.

Child↗
PubMedDate not supplied

Publication of abstracts submitted to the annual meeting of the Pediatric Orthopaedic Society of North America.

A computerized MEDLINE search was performed to determine the publication pattern of the abstracts submitted for podium presentation at the 1991-1994 annual meetings of the Pediatric Orthopaedic Society of North America (POSNA). The publication percentage for all papers submitted to the POSNA meetings from 1991 through 1994 was 45%. Fifty-three percent of papers accepted for podium presentation were ultimately published in comparison with 38% of those not accepted for presentation (p < 0.001). The mean time to publication was 29 months and did not differ significantly for the two groups. The majority of papers (65%) were published in either Journal of Pediatric Orthopaedics (48%) or The Journal of Bone and Joint Surgery (American) (17%). The frequency of ultimate publication of abstracts submitted to the annual POSNA meetings compares favorably with the rates for other medical subspecialties.

Abstracting and Indexing↗
PubMedDate not supplied

Effect of delay of surgical treatment on rate of infection in open fractures in children.

This study reviews all open fractures treated at a tertiary children's hospital from 1990 to 1995 to determine whether delaying surgical debridement influences the rate of infection in the pediatric population. One hundred four open fractures were followed until both clinical and radiographic union was evident. A 1.0% rate of infection requiring surgical drainage, and a 1.0% rate of soft-tissue infection managed with oral antibiotics alone was found. Infection rates for fractures treated within 6 h of injury was 2.5%, and for fractures treated with >6 h delay was 1.6%. No significant statistical difference in infection rate with delay in surgical debridement was found (p = 0.77). Delays of 5 and 16 h were found in the two fractures complicated by infection, compared with an average delay of 12 h for those that healed uneventfully. Our findings suggest that in children given early parenteral antibiotics, operative irrigation and debridement may be delayed >6 h without an increased risk of infection. As this series contains only 18 patients with grade III open fractures and nine patients whose surgery was delayed >24 h, conclusions should not be made in these groups.

Adolescent↗