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Biomedical subjects

T H Parker

Publications and source records attributed to T H Parker.

11 recordsLinked to original sources
PubMed2005

Quantitative genetics of ontogeny of sexual dimorphism in red junglefowl (Gallus gallus).

We studied phenotypic patterns and underlying quantitative genetics of development of sexual size dimorphism in red junglefowl (Gallus gallus). Using a multigenerational pedigree and the 'animal model' technique, we found significant heritability for many of the size and growth-related traits we examined, as well as significant genetic correlations among them. Despite sexual size dimorphism throughout posthatching ontogeny, the genetic correlation between males and females for all size measurements and growth parameters remained high. Significant positive phenotypic and genetic correlations between the fastest rate of growth and mass at week 26 (near asymptote) indicate that faster growth when young promotes larger adult size. However, age at which peak growth is reached does not appear to be phenotypically or genetically correlated with adult size. Positive genetic correlations within traits among ages were common, demonstrating that the genetic variance important to growth is relatively consistent among ages. However, male mass and tarsus length showed no genetic correlation between week 0 values and those from later ages. The body size traits of mass and tarsus length were genetically correlated with each other in females, but this pattern was not significant in males. Thus, despite striking sexual dimorphism in size and growth trajectories, size dimorphic traits in junglefowl show, with some exceptions, genetic integration between the sexes, among ages, and between traits.

Animals↗
PubMed2004

Quantitative genetics of sexually dimorphic traits and capture of genetic variance by a sexually-selected condition-dependent ornament in red junglefowl (Gallus gallus).

We studied the quantitative genetics of sexually selected traits in a captive population of red junglefowl (Gallus gallus L.) using a multi-generational 'animal model' approach. We found significant heritability of mass, tarsus length (both strongly sexually dimorphic), residual mass, and male comb (a fleshy head ornament) length. Residual mass has a genetic correlation between the sexes smaller than unity and so could show partially independent responses to selection in the two sexes. In males, tarsus length and mass were not genetically correlated, and this produced a negative genetic correlation between tarsus length and residual mass. The male red junglefowl's comb, an ornament influencing female choice, is highly condition dependent. We show that expression of this ornament is heritable, however, and shows strong genetic correlation with a condition index, residual mass. Because residual mass is partly influenced by various aspects of condition, it appears that comb size has 'captured' genetic variability in condition.

Analysis of Variance↗
PubMed1986

Exogastric leiomyoblastoma: a rare gastric neoplasm mimicking left hepatic mass on computed tomography.

Leiomyoblastomas are rare gastric neoplasms that may occur as exogastric masses, producing difficulty in correct localization and diagnosis. Two exogastric leiomyoblastomas were misdiagnosed as primary hepatic lesions due to their appearance on computed tomography. A discussion of these rare neoplasms, the potential for their erroneous diagnosis, and ways to avoid this computed tomography pitfall is presented.

Aged↗
PubMed1985

Parathyroid cyst.

Although parathyroid cyst has been infrequently reported until the past decade, its presumed rarity is attributed to nonrecognition. First reported in 1905, only 58 cases of parathyroid cyst had been documented in the world literature by 1967. Since then, however, substantial literature about this entity has been accumulating. The three cases we are reporting bring the cumulative total to 149. All three have been examined histologically and treated by aspiration or surgical excision. There is confusion clinically with thyroid cysts, and assay of fluid aspirate for parathormone and thyroxine may not accurately distinguish the origin of the cyst. Tissue diagnosis is confirmatory. Parathyroid cysts may be developmental, arising from vestigial remnants of the third and fourth branchial clefts; or coalescence of microcysts with associated hypersecretion may enlarge into macrocysts; or an adenoma may degenerate into a pseudocyst. Hyperparathyroidism, if present, is associated with only the last two.

Adult↗
PubMed1977

Nissen fundoplication for reflux peptic esophagitis.

One hundred sixty-five patients with reflux peptic esophagitis have been treated by Nissen fundoplication. When compared with a group of 104 patients reported five years ago, the incidence of persistent or recurrent esophagitis remains approximately the same (10% versus 8%). This is consistent with the assumption that the Nissen procedure when initially successful tends to remain so and that late recurrence appears to be uncommon. The unpleasant postoperative sequela which we have termed the "gas-bloat syndrome" was noted in 1971 to be present in the early postoperative period in approximately one-half the patients. Late follow-up, however, averaging four years indicates a marked reduction in this disorder with either absence or clinical insignificance in 87% of patients. Nonetheless, moderate symptoms persist in 11% and severe symptoms requiring active treatment in 2%. Manometric study of the lower esophageal sphincter indicates nearly a three-fold increase in resting pressure following Nissen fundoplication (p less than .001). It is hoped that manometric study will provide a more reliable prognostic measure of sphincter restoration than the measurement of pH across the gastroesophageal junction.

Esophagitis, Peptic↗