Biomedical subjects

E Dillwyn Williams

Publications and source records attributed to E Dillwyn Williams.

3 recordsLinked to original sources

PubMed2004

Modulation of N-methyl-N-nitrosourea-induced crypt restricted metallothionein immunopositivity in mouse colon by a non-genotoxic diet-related chemical.

Red meat consumption is associated with endogenous metabolic generation of mutagenic N-nitroso compounds (NOC) and may be implicated in causation of colorectal cancer. Assessment of a biologically relevant dose of NOCs is hampered by imperfect understanding of NOC interactions with other dietary components. This study tests the hypothesis that NOC effects upon mutational biomarkers in mouse colon may be modulated by a non-genotoxic diet-related compound. N-methyl-N-nitrosourea (MNU) and undegraded lambda carrageenan (lambdaCgN) were selected as test chemicals, representing a NOC and a non-genotoxic agent, respectively. Study end-points included (i) DNA adduct formation and (ii) metallothionein (MT) crypt restricted immunopositivity indices (MTCRII) which are considered representative of crypt stem cell mutations. Frequency and size of MT immunopositive foci as well as total number of MT immunopositive crypts were assessed. Biologically effective doses of MNU and lambdaCgN were determined in model validation studies and the agents were then tested alone and in combination. Continuous lambdaCgN treatment for 10 weeks induced significantly greater colonic mucosal injury than a drinking water control. In combined treatment regimens, lambdaCgN treatment did not significantly affect MNU-induced DNA adduct formation. However, combinations of lambdaCgN with MNU significantly increased MTCRII in excess of those induced by MNU alone. Recurrent or continuous lambdaCgN regimens had greater interactive effects with MNU upon MTCRII than short-term lambdaCgN treatment. This study has shown that exposure to a non-genotoxic diet-related compound (lambdaCgN) modulates the effective NOC dosimetry for induction of MT crypt restricted immunopositivity.

Alkylating Agents↗

PubMed2004

Thyroid implants after surgery and blunt trauma.

The differential diagnosis of thyroid tissue found laterally in the neck includes several conditions: lymph node deposits of thyroid carcinoma, "benign metastatic thyroidosis," detached thyroid nodules, and true ectopic thyroid tissue. We have studied nine cases with thyroid deposits in the soft tissues of the neck that do not conform to these diagnoses. We present evidence that they represent surgical or traumatic implantation of thyroid neoplasms. Eight of the nine cases presented one to 26 years after initial surgery. Adequate information of the operative procedure was available in seven cases, one patient underwent subtotal lobectomy and six subtotal thyroidectomy for a nodular gland. The nodules occurred within the operation field with no evidence that they were within lymph nodes. In six cases, birefringent particles consistent with talc from the earlier operation were found adjacent to the nodules. Three cases showed implants of colloid nodules, three of follicular adenoma, one of oncocytic (Hürthle) cell adenoma and one of follicular carcinoma. In the ninth case, infiltrating thyroid tissue in muscle and fibrous tissue presented 3 years after major blunt trauma to the neck. The tissue resembled that in a disrupted thyroid nodule present in the gland itself and was regarded as traumatically implanted. The observation that surgery or trauma to a nodular thyroid can occasionally lead to multiple subcutaneous thyroid implants has implication for management of thyroid disease. Therapy may be difficult; recurrence followed surgical removal of the nodules in three cases, and radioiodine may be a more effective therapy. Recognition of this entity is important for accurate pathologic diagnosis. It is apparently limited to implantation of tumor. The absence of implantation of normal or hyperplastic thyroid, despite the high frequency of partial thyroidectomy in Graves' disease, has pathobiological implications. These findings also support the generally held view that lobectomy rather than nodulectomy is the operation of choice for a solitary nodule.

Adult↗

PubMed2002

Pathology of the autonomously functioning (hot) thyroid nodule.

We describe the pathologic findings of 73 clinically and scintigraphically confirmed hot nodules. In general, hot nodules from an unselected group primarily treated by surgery were smaller and the sex ratio was closer to equality compared with the ample female predominance in the referral, pre-, and post-prophylaxis groups. Malignancy was observed in six cases (8.2%) (5 follicular, 1 papillary). Of the 67 benign tumors, 48 (71.6%) were adenomas which showed the cytoarchitectural features of hot nodules described previously, and 19 (28.3%) were less well-differentiated adenomas that included a few oxyphil tumors. Intracolloid oxalate crystals from background thyroid tissue were present in 59 assessable cases (83%) overall, the majority showed more than occasional crystals that had a tendency to increase in number with decreasing morphologic activity of the thyroid epithelium. Thyroglobulin protein and mRNA stainings tended to be more pronounced in cell cytoplasm of the tumors than in background thyroid. This study shows that hot nodules may show a wide morphologic spectrum of follicular neoplasms and can be occasionally malignant. It is inferred from the morphologic and other findings that it is likely that some, if not all, of the primary follicular cancers associated with hyperfunction arise by clonal progression from benign hot nodules. This progression is rare, probably because most hot nodules present with the symptoms of hyperfunction and receive early treatment.

Adenoma↗