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Biomedical subjects

P Dallas

Publications and source records attributed to P Dallas.

5 recordsLinked to original sources
PubMed2005

Dermatofibrosarcoma protuberans occuring in a child.

Dermatofibrosarcoma protuberans (DFSP) usually occurs in adults, however it can also occur in infancy and childhood. Diagnosis of DFSP in children is quite difficult given the rarity of the tumor and its variegated appearance. The behavior of this neoplasm is of borderline or intermediate malignancy with a high rate of recurrence but limited metastatic potential. We present the case of an eleven-year old boy who presented with a slightly raised, not tender lesion on his right shoulder. It had appeared two years before as a red-brown plaque and since then it had gradually grown to a nodule. An excisional biopsy was performed, and the diagnosis of DFSP was made based on the histological and immunohistochemical findings.

Biopsy↗
PubMed1996

Giant hemangioma in infant. A case presentation and literature review.

Giant hemangioma of infancy is a rare and extensive variant of the hemangiomas, that occurs in newborns and infants and is often complicated by life-threatening events. We describe herein an unusual case of a giant hemangioma in a female infant. At the age of 45 days she was admitted to the hospital because of increasing respiratory distress and distented abdomen. The response to supportive therapy was poor and the infant died from cardiac arrest on its 75th day of life. Autopsy revealed a giant tumor occupying extensive areas of the thoracic and abdominal cavity. The histologic diagnosis was compatible with a giant capillary hemangioma. A review of the literature was also attempted.

Abdominal Muscles↗
PubMed1991

Genetic variation in the Heterodoxus octoseriatus group (Phthiraptera): a test of Price's model of parasite evolution.

Most of the genetic variation in the H. octoseriatus group is present as fixed gene differences between species which have been described on morphological criteria. Based on allozymes, the taxonomic status of some species was challenged. There was insufficient evidence, however, to demonstrate that these were not 'good' biological species. Overall, the limited intraspecific variation was present as fixed gene differences among lice from different hosts and from different colonies of hosts; heterozygotes were rare. Two predictions derived from Price's model of parasite evolution were met: populations of lice were genetically homogeneous and, where genetic markers were present, we found substantial genetic variation among populations. These data contrast with those for endoparasitic helminths, where, in general, the amount of genetic variation is similar to that of free-living invertebrates.

Animals↗
PubMedDate not supplied

Accumulation of vinblastine into transfersomes and liposomes in response to a transmembrane ammonium sulfate gradient and their cytotoxic/cytostatic activity in vitro.

Vinblastine was encapsulated into liposomes composed from lipids dimiristoylphosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC), with cholesterol and transfersomes with sodium cholate prepared by the thin film hydration method. The percentage of vinblastine encapsulation, the stability of transfersomes and liposomes and the rate of release of encapsulated vinblastine at 37 degrees C were studied. The results showed that encapsulation of vinblastine into liposomes was higher than 98% at a drug/phospholipid molar ratio from 0.17 to 0.18, while encapsulation of vinblastine into transfersomes varied from 50% to 80% at a drug/phospholipid molar ratio from 0.05 to 0.09. The retention of drug in liposomes and in transfersomes was found to be time/dependent. The retention of drug in transfersomes compared to the liposomes was reduced due to the presence of sodium cholate which caused destabilization and reduced the main phase transition temperature Tm of the PC bilayers. The cytotoxic/cytostatic activity of the two liposome formulations and the two transfersome formulations with or without encapsulated vinblastine were examined against nine human cell lines and the parameters GI50, TGI, LC50 were estimated according to the NCI protocol. Free DPPC/sodium cholate liposomes found to exhibit strong antiproliferative activity in contrast to the other three free liposomal formulations (DPPC/cholesterol, DMPC/cholesterol, DMPC/sodium cholate). On the other hand, vinblastine encapsulated into the liposomes found to exhibit 20-fold less activity on average, in the three parameters calculate compare to the free vinblastine.

1,2-Dipalmitoylphosphatidylcholine↗