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Biomedical subjects

D J Ryan

Publications and source records attributed to D J Ryan.

8 recordsLinked to original sources
PubMed2005

Suppression of the cysteine protease, aleurain, delays floret senescence in Brassica oleracea.

An aleurain-like protein, BoCP5, is up-regulated during harvest-induced senescence in broccoli floret and leaf tissue. BoCP5 is most closely related to an Arabidopsis protein (91%, AAF43041) and has 71% identity to barley aleurain (P05167). The mRNA for this gene accumulates within 6 h after harvest in broccoli florets, and its expression is reduced in tissue that has been held in senescence-delaying treatments (e.g. water, sucrose feeding, controlled atmosphere). The gene is also expressed in leaves during aging-related and harvest-induced senescence. Analysis of protein bands that cross-react with antibodies raised to the bacterial BoCP5 fusion protein, revealed prominent immunoreactive bands at ca. 26, 28, 31, and 38 kD in floret tissue. The 31 kD band was absent in protein extracts from leaf tissue. Agrobacterium-mediated transformation was used to produce transgenic broccoli plants with down-regulated BoCP5. A reduction in the postharvest expression of BoCP5 in floret tissue was achieved for four transgenic lines in the current study. In three of these lines postharvest floret senescence (yellowing) was delayed, and florets contained significantly greater chlorophyll levels during postharvest storage at 20 degrees C than wild-type plants. Line 4 showed the greatest down-regulation of BoCP5, and in this line postharvest protease activity remained at pre-harvest levels, and the yield of soluble proteins extracted from florets after harvest was significantly greater than that of wild-type tissue.

Amino Acid Sequence↗
PubMed1976

The etiology and porotic hyperostosis among the prehistoric and historic Anasazi Indians of Southwestern United States.

Porotic hyperostosis was studied in 539 crania from maize-growing prehistoric and historic groups who occupied two dissimilar ecological zones of the Plateau country of Arizona and New Mexico--canyon bottoms and sage plain. Defined as abnormal localized sieve-like structural changes involving the hematopoietic areas of the cranium, it was found in 185 (34.3%) of these skulls. More frequent in children than in adults, it shows significant frequency differences between both children and adults of the two ecological zones. The two ecological zones differ in the availability of iron in the diet; the canyon inhabitants depended heavily on maize (which interferes with iron absorption) while the sage plain people consumed more iron-rich animal products. We hypothesize that an increased dependence on maize produced more iron deficiency anemia and resulted in more porotic hyperostosis. Maize is known to have permitted a food surplus which in turn allowed for increased Southwestern population growth in marginal areas like the canyon bottoms. Heavy dependency on a single food type with consequent hematologic problems may have been an important reason for the subsequent abandonment of the Anasazi region.

Adult↗
PubMed1975

The paleoepidemiology of porotic hyperostosis in the American Southwest: Radiological and ecological considerations.

Porotic hyperostosis was observed in 34 percent of 539 crania excavated from sites in Arizona and New Mexico. Common causes of this cranial pathology in the Old World (thalassemia, sickel cell anemia, and malargia) do not explain its occurrence in the American Southwest, as malaria and hemoglobinopathies are not known to have existed in the New World prior to European contact. Iron deficiency anemia which may also be assoicated with porotic hyperostosis occurs on a mass level only with hookworm infestation or nutritionally-related iron deficiency. Since hookworm infestation is rare in the American southwest and has not been reported in prehistoric southwestern American Indians, the hypothesis of nutritional anemia was examined. In canyon bottom sites where the diet was heavily dependent on maize, which is low in iron and also contains an inhibitor of iron absorption, significantly more crania had porotic hyperostosis than in sage plain sites, where the diet included ample animal protein rich in easily absorbable iron (p less than .001). Furthermore, canyon bottom children, who were more susceptible to iron deficiency anemia, had a higher incidence of porotic hyperostosis lesions than adults (p less than .0001).

Adult↗
PubMedDate not supplied

Intoeing: a developmental norm.

Intoeing, often referred to as pigeon-toes, is a frequent reason for referral to the pediatric orthopaedic surgeon's practice. Parents and grandparents are concerned about the appearance of the legs and a history of frequent tripping and falling. Many of the "abnormalities" that these children present with are variations of normal development of the lower extremities and include flat footedness, and torsional or angular "deformity." The approach of the specialist team is to identify the source of the intoeing, to rule out neuromuscular dysfunction or other serious conditions, and to counsel the family on anticipatory guidance of the natural history of intoeing. The focus of this article is intoeing, associated examination techniques, and nursing considerations of education and treatment. An understanding of musculoskeletal developmental norms, the clinical examination for intoeing, and the current recommendations for treatment will enable the provider to educate and accurately inform families.

Bone Diseases, Developmental↗