Biomedical subjects

R A Preti

Publications and source records attributed to R A Preti.

26 records · Page 2Linked to original sources

PubMed1993

ISHAGE bone marrow processing survey: report on an international information gathering process. International Society for Hematotherapy Graft Engineering.

Significant amounts of information are currently available within the database generated by the responses to the Bone Marrow Processing Survey. As additional Surveys are returned, the data will continue to be entered into a Lotus spreadsheet, until a more sophisticated database with a programmed interface becomes available. The readership is encouraged to enter or edit the databank by returning a completed or amended Survey to the Society. Copies of the form are available from the Society or can be found in the first issue of the Journal of Hematotherapy.

Blood Transfusion, Autologous↗

PubMed1992

Hemopoietic stem cell processing: comparison of progenitor cell recovery using the Cobe 2991 cell washer and the Haemonetics V50 apheresis system.

Using 24 bone marrow (BM) harvests intended for cryopreservation and transplantation, we compared the use of the Cobe 2991 cell washer (2991) and the Haemonetics V50 apheresis system (HV50) for automated BM processing. Our in vitro data indicate that while the mononuclear cell (MNC) concentration of the HV50 product was significantly greater than that of the 2991, the overall MNC recovery of the two products was equivalent. In addition, although the concentration of CFU-GM and BFU-E in the products was equivalent, recovery of these progenitors in the 2991 product was significantly greater than those of the HV50 product. There was no significant difference in either the final product concentration or the overall recovery of cells bearing the primitive myeloid antigens, CD33 or CD34, between the two methods. The HV50 product volume, the red cell and the granulocyte mass were significantly lower than those of the 2991. We conclude that the advantages gained through the use of each machine should be evaluated within the context of the specific intention for the graft. Future advances in the identification and understanding of the primitive stem cell will aid in attempts to evaluate the methods used to isolate these cells.

Adolescent↗

PubMed1987

Hematopoiesis on nylon mesh templates. I. Long-term culture of rat bone marrow cells.

Rodent hematopoietic cells have been perpetuated in long-term bone marrow culture (LTBMC), provided that they were plated onto a pre-established layer of bone marrow stromal cells (fibroblasts, reticular cells, adipocytes, macrophages, etc.). This monolayer-type system supports the self-renewal of murine pluripotent stem cells and produces substantial numbers of progenitors and mature cells of the myeloid lineage. In an effort to increase the growth potential of cells in LTBMC, an adherent matrix of stromal cells was established on a pretreated nylon screen template. Subsequent seeding of hematopoietic cells onto this matrix occurred both on the surface of the adherent layer and in the interstices formed by the developing stromal cells. A three dimensional growth pattern of hematopoietic colonies and clusters was observed. Mature cells and late stage precursors of the myeloid and erythroid series were observed in the non-adherent layer for the duration of the experiment (39 weeks). Cells similar in appearance to small lymphocytes were also seen in both the non-adherent and adherent layers. Cells associated with the adherent layer of this LTBMC system displayed the ability to reconstitute hematopoiesis in the irradiated host. It is suggested that because of its three-dimensional nature the nylon mesh LTBMC system possesses a greater hematologic potential per unit area than monolayer-type LTBMC.

Animals↗

PubMed1985

The effects of interferon on murine erythropoiesis.

The effects of interferon (IF) on erythropoietin (Ep) action and production were studied in mice. In comparison to control animals, Ep action in exhypoxic, polycythemic mice was significantly decreased (p less than 0.05) following two low dose injections of IF (2.9-3.5 X 10(4) units). In addition, renal Ep production in normal intact mice was also significantly decreased (p less than 0.01) following a single injection of IF (5.4-6.3 X 10(4) units) and hypoxic exposure.

Animals↗

PubMed1984

The effect of methylcellulose on extrarenal erythropoietin production.

The macromolecular polymer, methyl cellulose (MC), is a known hepatosplenomegalic agent which promotes a state of experimental hypersplenism in rats. This is characterized by massive splenomegaly, pancytopenia of the blood elements, medullary hypoplasia, and marked gross and histologic alteration of the liver, kidney, adrenals, and lungs. Massive splenomegaly results from storage of this inert material by splenic macrophages. In the present study, chronic MC administration in rats augmented the hepatic Ep response to hypoxia but did not appreciably affect renal production of Ep. Splenectomy resulted in a decrease in the extrarenal Ep response to hypoxia indicating a possible role of the massively enlarged spleen of these MC-treated rats in extrarenal Ep production. The augmentation of extrarenal Ep elaboration may be attributed to a stimulatory effect of MC on the hepatic and splenic macrophages.

Animals↗

PubMed1984

Hepatic and renal erythropoietin production during various intervals of short-term hypoxia.

Hypoxia stimulates erythropoietin (Ep) production and subsequent stimulation of erythropoiesis. Chronically applied hypoxia results in a variety of physiological alterations including polycythemia, hemoglobinemia, and vascular and metabolic changes. As red cell mass increases to such an extent to allow for adequate tissue oxygenation, plasma Ep levels drop and the rate of erythropoiesis is lowered. In the present work, the precise contribution of the kidney and the liver to the Ep response to acutely administered hypoxia (6-24 hr/0.4 atm) was determined using an in situ tandem perfusion of the liver and kidneys. The results indicate that hepatic and renal Ep production during different intervals of acute hypoxia is not uniform. This alteration may be partially explained by the reported reduction in splanchnic blood flow and a possible redistribution of hepatic microcirculation, which may cause the liver to become more hypoxic than the kidney under the same ambient pO2. The role of the liver becomes more pronounced as the time of acute hypoxic exposure increases, whereas the Ep content of renal perfusates is not drastically altered. At certain intervals during hypoxia, the liver displays a greater potential to elaborate Ep.

Animals↗

PubMedDate not supplied

Challenges associated with the development, manufacturing, and delivery of cellular medicines.

As the potential of these exciting therapeutics approaches reality, the challenges associated with their discovery, approval, and widespread distribution are just now being realized. The current health care infrastructure is unable to accommodate the complexity of cellular therapy, which exceeds the capability of existing treatment facilities to provide ready access for patients to receive standardized collections for consistent quality of apheresis product and the most consistently acceptable and potent therapeutic agent. The goal is to develop a system for seamless international access to cellular therapies and will involve the unification of the systems for the collection of patient-specific cellular materials, the development of an international network of FDA (and other regulatory agencies) registered facilities, the preservation of patient-specific product control from acquisition to re-infusion, the integration of a sophisticated transportation network to meet the time and environment-critical nature of the raw materials and the finished product, and the development of a comprehensive informatics system to coordinate all of the elements.

Cell Transplantation↗

PubMedDate not supplied

Temporal relation between a hepatic erythropoietic factor and the site of rat erythropoietin production.

Serum borne hepatic erythropoietic factor (HEF), which can stimulate hepatic erythropoietin (Ep) production in the adult rat, is found at elevated levels in the serum of partially hepatectomized rats and of rats subjected to hepatotoxic injury. It is also detected in sera of patients with liver disease. The purpose of the present study was to determine whether or not HEF activity is increased in the serum of the normal neonatal rat at a time when the liver is the primary site of Ep production. Our results show significantly increased HEF activity in the serum of young rats during the second to fifth weeks of life. Negligible activity was detected in rats over five weeks of age. In the rat, the kidney is reported to begin producing Ep by the third week of life and by the eighth week the kidney is the major site of synthesis with liver production at this age significantly diminished. Thus, our findings show a temporal relation between HEF activity in the serum and the reported transition from liver to kidney production of Ep.

Animals↗