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Biomedical subjects

A Liu

Publications and source records attributed to A Liu.

224 records · Page 13Linked to original sources
PubMed1977

Effect of procaine HCLl on ATP: calcium-dependent alterations in red cell shape and deformability.

Procaine hydrochloric acid, a cationic anesthetic, although unable to prevent the effect of calcium ionophore A23187 on erythrocytes, inhibited the discocyte--echinocyte transformation, increased viscosity, and decreased filterability of red cells undergoing ATP depletion. The effects were abolished by washing ATP-depleted, procaine HCl-treated red cells prior to these determinations. Procaine HCl had no effects on volume, incubated osmotic fragility, or monovalent cation composition of ATP-depleted red cells. The drug increased 45Ca uptake by ATP-depleted red cells but did not change the fraction of membrane-bound calcium. Sodium dodecyl sulfate acrylamide gel electrophoresis of membrane proteins from ATP-depleted red cells revealed formation of high molecular weight protein complexes, which were not formed when biconcave shape and ATP content were maintained by incubation with adenine (0.54 mM) and inosine (12.7 mM); Formation of these complexes was not prevented when the biconcave shape was maintained by procaine HCl. It was concluded that the maintenance of the biconcave shape and normal deformability during ATP depletion by procaine HCl was not related to a displacement of membrane-bound calcium and inhibition of ATP-dependent rearrangement of red cell membrane proteins.

Adenosine Triphosphate↗
PubMedDate not supplied

Chromosome evolution of the blue sheep/bharal (Pseudois nayaur).

A male dwarf blue sheep was collected 60 km south of Batang east to the Jinsha Jiang river, and a male Subei blue sheep (Greater form) was collected from Gansu, China, representing two geographically separated blue sheep forms. Chromosome preparations were prepared from fibroblast cultures. The dwarf blue sheep has a 2n = 54 and a karyotype with three biarmed formations that resulted from acrocentric chromosome fusions (based on the 2n = 60 Capra autosomal equivalents) 14p/5q, 27p/1q, and 29p/2q from the largest to the smallest biarmed chromosome, respectively. The 14p/5q fusion is metacentric, whereas the 27p/1q and 29p/2q are submetacentric. The Subei blue sheep had a 2n = 56, with only the 27p/1q and 29p/2q biarmed chromosome fusions. The remainder of the chromosomes in both blue sheep are acrocentric; the X is the largest acrocentric chromosome and the Y is a minute biarmed chromosome. Our observation is one evidence showing that chromosome evolution within blue sheep has followed a series of centric fusions resulting in the reduction of chromosome number, which is typical of all extant genera within the tribe Caprini.

Animals↗
PubMedDate not supplied

Effect of malnutrition at the time of diagnosis on the survival of children treated for cancer in El Salvador and Northern Brazil.

PURPOSE: To investigate the relationship between survival and malnutrition at the time of diagnosis among children treated for cancer in two developing countries. PATIENTS AND METHODS: We studied 443 children treated for cancer between 1995 and 1998 at two centers in San Salvador, El Salvador, and Recife, Brazil. Median age at diagnosis was 4.9 years; 283 children had leukemia and 160 had solid tumors. Z-scores were calculated for weight for age (WAZ), height for age (HAZ), and weight for height (WHZ) at diagnosis. Z scores <-2 indicated malnutrition. Patients were also stratified by low-risk disease (solid tumors: stage I, stage II, or localized; acute lymphocytic leukemia: white blood cell count <25,000/microL, no central nervous system involvement, no mediastinal mass and age >1 and <10 yrs) and high-risk disease (all other patients, including those with acute or chronic myelocytic leukemia). RESULTS: Z-scores indicated malnutrition in 23.5% (WAZ), 22.8% (HAZ), and 15.7% (WHZ) of patients. Z-score was not significantly related to overall survival rates, to survival rates analyzed by type of malignancy or risk status, or to survival rates at the end of the first month of treatment. CONCLUSIONS: We found no relationship between nutritional status and survival in these patients. This implies that future protocols for use in developing countries can be designed to provide optimal treatment intensity despite the high incidence of malnutrition.

Brazil↗
PubMedDate not supplied

Activation of autologous or HLA-identical sibling cytotoxic T lymphocytes by blood derived dendritic cells pulsed with tumor cell extracts.

This study describes the effect of dendritic cells (DC) pulsed with tumor cell extracts on the induction and activation of autologous and HLA-identical sibling tumor cell specific cytotoxic T lymphocytes (CTL). The subjects of the study were patients with hematological malignancies (acute myeloid leukemia, acute lymphoblastic leukemia, and multiple myeloma), and stem cell transplant donors. Although lymphocytes primed with non-pulsed DC did not show definite cytotoxic activity against autologous or HLA-identical sibling patient tumor cells, both autologous and HLA-identical sibling CTL activated by DC pulsed with tumor cell extracts demonstrated markedly significant killing activity against tumor cells in the fashion of higher cytotoxicity with the increase of effector:target ratio (p<0.05). These findings reveal that DC pulsed with tumor cell extracts could be efficiently applicable in anti-tumor immunotherapy for patients with hematological malignancies.

Adult↗
PubMedDate not supplied

Estrogen and progesterone receptors can be maintained in normal human breast epithelial cells in primary culture and after transplantation into nude mice.

The estrogen and progesterone receptor expression was determined in breast epithelial cells from reduction mammoplasty specimens. Only a subset of the luminal epithelial cell population was found to be positive for these receptors. When these cells were subsequently cultured in 3-dimensional collagen gel system (in vitro model) or transplanted into nude mice (in vivo model), the cells retained their ability to express both receptors in these experimental systems. The maintenance of primary normal human breast epithelial cells expressing the estrogen and progesterone receptors in experimental systems has not been reported previously.

Animals↗
PubMedDate not supplied

Beware of contaminating mouse cells in human xenografts from nude mice.

Human tumor xenografts in nude mice are widely utilized model system for the transplantation of human surgical specimens and human established cell lines. Gene expression studies are often carried out in these model systems. With an increasing use of PCR based analyses, the extreme sensitivity of this technique poses a serious challenge with regards to the extent of contaminating host mouse cells in the human tumor xenografts. These xenografts are never free of host cell contamination. We detected mouse estrogen receptor expression in several human tumor xenografts using RT-PCR demonstrating that precaution is necessary when utilizing PCR based analyses in human tumor xenografts. A cytologically based methodology which distinguishes human versus mouse cells will be more suitable for ER expression studies using human xenograft models. Both (1) in situ hybridization using human probe and (2) immunocytochemistry using a monoclonal antibody directed against human cytokeratin have been used successfully to distinguish human cells versus host mouse cells in human xenografts in nude mice. Immunostaining of ER can then be utilized to determine the expression pattern of ER in the transplanted human cells.

Animals↗