Publications by authors named "John Langdon"

Discussions of the evolution of sexual dimorphism in torso shape and the pectoral region assume that this dimorphism exists independently of body size. We test this assumption in two human populations and further examine what is needed to understand sexual dimorphism in the pectoral region. Modern human males have broad shoulders and narrow hips relative to females, lending males a more triangular torso.

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Accounting for genotype-environment interactions may improve genetic prediction and parameter estimation. The objective was to use random regression analyses to estimate variances and thereby heritability for intramuscular fat (IMF) across longitude and latitude coordinates within the continental United States. Records from the American Hereford Association (n = 169,440) were used.

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Chromatography plays an important role in the downstream processing of proteins. Over the past years, there has been a steady move toward the adoption of more rigid, porous particles to combine ease of manufacture with increased levels of productivity. The latter is still constrained by the onset of compression where the level of wall support becomes incapable of withstanding flow-induced particle drag.

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Purpose: Application of ultrasensitive diagnostics has shown that small numbers of p53 mutation-positive cells may signify the presence of residual tumor in histologically normal tissues after resection of squamous cell carcinomas arising in the head and neck area. To date, most studies in this area have focused on analysis of tissues at the mucosal aspect of the resection and highlighted the importance of molecular changes in the field with respect to the risk of recurrence.

Experimental Design: In the present investigation, we analyzed normal tissues from mucosal and deep surgical margins, referred to as "molecular margins," for the presence of the signature p53 mutation identified for each tumor.

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A number of authors have argued that only an aquatic-based diet can provide the necessary quantity of DHA to support the human brain, and that a switch to such a diet early in hominin evolution was critical to human brain evolution. This paper identifies the premises behind this hypothesis and critiques them on the basis of clinical literature. Both tissue levels and certain functions of the developing infant brain are sensitive to extreme variations in the supply of DHA in artificial feeding, and it can be shown that levels in human milk reflect maternal diet.

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True malignant mixed tumours of the salivary gland (carcinosarcoma) are rare tumours composed of both carcinomatous and sarcomatous components. They predominantly occur in the parotid gland. This report presents the clinical, histological and imaging findings of a carcinosarcoma arising in the deep lobe of the parotid.

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Purpose: This study was designed to help establish the most appropriate samples and tests to detect disseminated tumor cells (DTCs) for head and neck cancer patients.

Experimental Design: Samples of bone marrow (BM) and central venous blood (CVB), collected preoperatively, and BM and peripheral venous blood, collected 3 months transcription postoperatively, were screened for the presence of DTCs using immunocytochemistry (ICC) with a pan-cytokeratin antibody and E48 reverse transcriptase-PCR. The molecular approach was also applied to intraoperative CVB.

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Although the pathogenesis of Warthin's tumour is not fully understood, it is generally thought that the tumour arises from heterotopic salivary ducts within pre-existing lymphoid tissue. Prolonged nitric oxide (NO) production by the enzyme type 2 nitric oxide synthase (NOS2) has been implicated in the pathogenesis of many solid tumours, but not in Warthin's tumour. Since NO and NOS2 are known to be associated with p53, the immunohistochemical expression of both NOS2 and p53 was investigated in 23 cases of Warthin's tumour.

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