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Biomedical subjects

R S Wells

Publications and source records attributed to R S Wells.

At least 19 recordsLinked to original sources
PubMed1990

Assignment of six enzyme loci to multipoint linkage groups in fishes of the genus Poeciliopsis (Poeciliidae): designation of linkage groups III-V.

Three new linkage groups of enzyme loci are described using Poeciliopsis monacha x P. viriosa-derived interspecific backcross hybrids. Comparison to known linkage groups of the confamilial genus Xiphophorus shows homology between Xiphophorus linkage group I and Poeciliopsis linkage group III, Xiphophorus linkage group II and Poeciliopsis linkage group I, and Xiphophorus linkage group IV and Poeciliopsis linkage group IV. Comparison of the gene content of other fish, amphibians, and mammal syntenic groups suggests retention of plesiomorphic vertebrate gene arrangements in at least two poeciliid linkage groups. Expansion of the Poeciliopsis gene map should be of utility in the identification of tumor regulatory genes through demonstration of linkage to biochemical markers.

Animals↗
PubMed1989

Familial keratoses of actinic distribution associated with internal malignancy and cellular hypersensitivity to UVA.

In members of a family there appeared to be an association between the development of cutaneous pigmented keratoses in sun-exposed sites, and the later evolution of internal malignancies, particularly carcinoma of the uterus. Affected individuals were not clinically photosensitive, but their fibroblasts demonstrated gross cytopathic changes, low survival indices and an increased frequency of DNA single strand breaks following exposure to long-wave ultraviolet radiation (UVA). These clinical and cellular features appear to identify an unrecognized syndrome that may not be uncommon. Recognition of this syndrome in a family may prevent certain malignancies developing in those affected.

Adult↗
PubMed1989

Inferring emotions from multiple cues: revealing age-related differences in "how" without differences in "can".

This study examined differences in children's use of social cues to make emotional inferences. Children ages 4, 5, and 8 years were presented with stimuli that depicted another child in affectively congruous and affectively incongruous expression/situation combinations. The intensity of positive and negative facial expressions was varied across situations. Subjects judged the target's feelings and selected among the alternative facial expressions or situations the one they had just seen. No significant age-related differences were found in the extent to which children registered and used both the expressive and situational information when making emotional inferences. The main experimental measure asked children to explain their judgments. In explaining their judgments, subjects' rationales indicated that they: (a) used both the situational and expressive cues; and (b) were sensitive to congruous versus incongruous cues, and even to mild versus strong incongruous cues. Children's rationales also reflected a sensitivity to expressive and situational negativity. For each age group, the rationales were more elaborate when the cues were problematic. Characteristic strategies, however, were also found for each age group. These distinct strategies may reflect social-life changes in children's social "theories" of emotion.

Age Factors↗
PubMed1988

Differentiation of ICM cells into trophectoderm.

It has been established previously that when inserted in the blastocyst E Ca 247 preferentially differentiates into trophectoderm in vitro. If the concept that tumors are caricatures of the process of tissue renewal is correct, then some cells from the inner cell mass (ICM), the normal counterpart of embryonal carcinoma, should be able to differentiate into trophectoderm. This has been a controversial issue. Four experiments are now reported that support the idea that ICM can differentiate into trophectoderm: 1) ICM from early blastocysts after classical immunosurgery made blastocysts in vitro; 2) ICM obtained from early blastocysts by immunosurgery using antigens other than histocompatibility ones made blastocysts in vitro; 3) ICM from early blastocysts, in which the trophectodermal cells had been labeled, contained no labeled cells following immunosurgery; and 4) In reconstruction experiments, polar and mural trophectodermal cells attached to ICM from late blastocysts failed to multiply and make blastocysts when cultured. It is concluded that like the embryonal carcinoma some ICM cells of early blastocysts have the potential to make trophectoderm. This fact is consistent with the concept that tumors are caricatures of the process of tissue renewal; and establishes E Ca 247 as a good model for study of trophectodermal differentiation.

Animals↗
PubMed1987

Pachyonychia congenita with cutaneous amyloidosis and hyperpigmentation--a distinct variant.

Two kindreds manifesting an unusual form of pachyonychia congenita are described. Clinical involvement consists of nail dystrophy, which tends to improve with age, and moderate palmoplantar hyperkeratosis. In addition, all affected members show a characteristic pattern of cutaneous hyperpigmentation, which resembles macular amyloidosis around the neck and waist, but which confers a dappled appearance to the axillae, popliteal fossae, thighs, buttocks, and lower aspect of the abdomen. With advancing age the pigmentation fades. Histologic and ultrastructural examination of the hyperpigmented skin has revealed pigmentary incontinence and deposition of amyloid within the papillary dermis. These features appear to constitute a distinct variant of pachyonychia congenita.

Adolescent↗
PubMed1987

The fate of embryonal-carcinoma cells in mouse blastocysts.

Double-labeled embryonal-carcinoma (ECa) cells were injected into blastocysts or incorporated into blastocysts by aggregation, and their fate after various periods of time in culture was investigated. ECa-247 cells labeled with fluorescent microscopheres were easily identified in whole blastocysts. These blastocysts were embedded in plastic, serially sectioned, and prepared for autoradiography. The 3H-thymidine label on the embryonal-carcinoma cells allowed precise localization of the cancer-derived cells. ECa-247 cells preferentially localized in the mural trophectoderm, with a few being seen in primitive endoderm and, even more rarely, in the inner cell mass. Selected autoradiograms were re-embedded and thin sectioned for transmission electron microscopy. The cancer-derived cells were found to have differentiated in accordance with their localization.

Animals↗
PubMed1986

Regulation of melanoma by the embryonic skin.

This report focuses on the regulation of murine melanoma by the embryonic skin. A surgical technique was developed to allow injection of B16 melanoma cells into the embryo in utero. A significant decrease in incidence of tumors was noted, which correlated with the time of arrival of normally migrating premelanocytes into the skin. Media were conditioned from skin explanted at the time premelanocytes arrive in it; these media inhibited the growth of melanoma cells in vitro. Under optimal conditions the growth of melanoma cells ceased; the cells had altered morphology and failed to proliferate when placed in fresh growth media.

Animals↗
PubMed1986

Widespread inhibition of neuroblastoma cells in the 13- to 17-day-old mouse embryo.

Previous experiments have demonstrated specific inhibition of tumor formation after neuroblastoma cells were injected into fragments of 8.5- to 9.5-day embryonic tissue (A.H. Podesta et al. Proc. Natl. Acad. Sci. USA, 81:7608-7611, 1984). The effect was localized to the somite and appeared specific for neuroblastoma as opposed to a variety of other tumor types. This regulation of neuroblastoma cells was believed to reflect an underlying event in the development of migrating embryonic neuroblasts. The current experiments were done to determine the effect on regulation with further embryonic development. The results indicated that later embryos (13 to 17 days of gestation) have a widespread inhibitory effect in all tissues tested, including the adrenal gland, testis, kidney, liver, limb bud, and heart. In contrast a leukemia cell line was not affected by any of these tissues. In organ culture demonstrable colony formation by neuroblastoma was likewise inhibited, and conditioned media from one of these embryonic sources (limb bud) slowed but did not abrogate growth of neuroblastoma cells.

Animals↗
PubMed1985

Metastatic cutaneous carcinoid.

A case of malignant bronchial carcinoid with multiple cutaneous metastases is reported. Despite the extremely aggressive behavior of the disease and the presence of multiple hepatic metastases, the patient did not exhibit the usual clinical features of the carcinoid syndrome. The relevance of the finding of elevated 24-hour urinary vanillylmandelic acid levels in patients with carcinoid tumors is discussed.

Aged↗
PubMed1984

The neurula stage mouse embryo in control of neuroblastoma.

The purpose of this study was to determine whether the neurula stage mouse embryo can regulate tumor formation of C-1300-3 neuroblastoma cells. Five neuroblastoma cells were injected into the second somite of neurula stage embryos, and their ability to form tumors was tested, 24 hr later, by transplanting the portion of the embryo containing the cancer cells into the testes of adult mice. Only one-third the number of tumors was obtained in comparison with controls in which (i) five neuroblastoma cells were injected into blocks of liver tissue that were then transplanted into the testes of adult animals or (ii) five C-1300-3 neuroblastoma cells were injected directly into the testes. When five C-1300-3 cells were injected into somites, which had been dissected from embryos, and the injected somites were placed in animals, significantly fewer tumors were obtained in relationship with controls. Although it is not known whether the neuroblastoma cells are induced to differentiate or are killed by the embryonic tissue, the effect appeared to be specific because the tumor-forming ability of L1210 leukemia, B-16 melanoma, embryonal carcinoma 247, and a parietal yolk sac carcinoma was unaffected by somites.

Animals↗
PubMed1984

Centrifugal lipodystrophy.

We describe a case of centrifugal lipodystrophy occurring in a young English girl, and compare the clinical and histopathological features with previous reports from Japan.

Child, Preschool↗