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Biomedical subjects

D C Mayer

Publications and source records attributed to D C Mayer.

24 records · Page 2Linked to original sources
PubMed1990

The cytolysis of human neuroblastoma cells by a natural IgM 'antibody'-complement system in pregnancy serum.

Cell lines from 26 human cancers were studied for cytotoxicity when treated with normal pregnancy serum. Cytotoxicity manifested by cell death and cytolysis, occurred in 4 of 8 neuroblastomas studied: SK-N-SH, NGP, LAN-5, and IMR-32. In NGP and SK-N-SH, evidence is presented showing that the cytotoxicity resulted from the cell-surface binding of a natural IgM 'antibody', which sensitized the neuroblastoma cells to the lytic action of complement (C). This system may be involved in a cytolytic form of spontaneous regression of neuroblastoma.

Cell Line↗
PubMed1989

Natural cytotoxicity of human serum. A natural IgM 'antibody' sensitizes transformed murine cells to the lytic action of complement.

The natural cytotoxicity of human serum on murine L cells, EA and Sa 180 cells is expressed as a rapid cytolysis at 37 degrees C. This cytotoxic system is analyzed as to its active constituents and their functional relationships. Ultrastructural studies indicate that cell injury and death are initiated within 10 min by membrane disruption. A trypan blue assay for cell death was used to study serum toxicity in individual normal healthy adults, pregnant females and newborn infants. Pregnancy sera, particularly in the 2nd and 3rd trimesters, were consistently more toxic than male serum or nonpregnant females. Cord serum was typically nontoxic. Pools of normal fresh pregnancy serum were used for immunochemical analysis of the cytotoxic activity. By a variety of immunologic and immunochemical techniques it was shown that the cytotoxicity was, in part, due to the combined action of alternative and classical pathways of complement, the former being more prominent. The lytic action of complement was shown to be greatly amplified by the prior adsorption of IgM on the target cells' surface. This IgM is a critical determinant of the cytotoxic reaction. It probably contains a natural 'antibody' to cell surface antigen(s), whose combination activates both pathways of C.

Animals↗
PubMed1988

Implantation of balloon-expandable intravascular grafts by catheterization in pulmonary arteries and systemic veins.

The purpose of this investigation was to evaluate the efficacy and safety of implanting expandable intravascular stents in pulmonary arteries and systemic veins. Twenty-seven balloon-expandable grafts were placed in 13 mongrel dogs under anesthesia. A long sheath was introduced over a wire and catheter or dilator into the pulmonary artery or target vein. A collapsed stainless steel expandable mesh stent was placed over the balloon of an angioplasty catheter. The catheter with the mounted stent was advanced through the sheath. The stent expanded to the diameter of the balloon as the balloon was inflated, and remained expanded as the balloon was deflated. The stent was expanded further with a larger balloon in 11 instances. Eleven stents were placed successfully in pulmonary arteries (out of thirteen attempted), and 11 of 14 were installed in tributaries of the precava or postcava. Three inadvertent embolizations of the devices occurred. All three devices that embolized lodged in the pulmonary arteries and did not obstruct flow. Seven dogs were recatheterized at intervals ranging from 56 to 278 days. Twelve stents were patent and nonobstructive, and two were malpositioned, one of which was obstructed. Three animals were killed 2 months (two dogs) and 9 months (one dog) after the implantations. The stents (four in the pulmonary arteries and two in veins) were completely covered with neointima and were patent, without thrombosis. These stents hold promise for definitive dilation of congenital or postoperative vessel stenoses.

Animals↗
PubMedDate not supplied

Effects of poloxamer 188 in a rabbit model of hemorrhagic shock.

Poloxamer 188 is a synthetic surfactant that reduces the viscosity of whole blood without hemodilution. It is postulated that poloxamer 188 would improve outcome if administered during retransfusion following hemorrhage. Rabbits were anesthetized and instrumented for 3 hours of hemodynamic monitoring. After stabilization, blood was withdrawn over a 5 minute period to reduce mean arterial pressure to 35 mmHg (4.7 kPa). Following a 60 minute shock period, animals were randomly assigned to 1 of 5 experimental groups (n = 8 in each): (1) Shock (no retransfusion); (2) Transfusion (retransfusion of autologous shed blood); (3) Volume (retransfusion with autologous blood and infusion of an additional volume of normal saline equivalent to the volume of poloxamer 188 given in the next 2 experimental groups); (4) Low and (5) High drug (i.v. bolus of 200 mg/kg of poloxamer 188 over 5 minutes at retransfusion, followed by a continuous infusion of poloxamer 188 at 50 mg/kg/hr in the Low drug group and 200 mg/kg/hr in the High drug group). All animals in a surgery Control group (n = 6) remained stable during the 3 hour monitoring period. In contrast, none of the animals in the Shock group remained alive, confirming this to be a relevant model of trauma and severe hemorrhagic shock. There were significantly more animals surviving at the end of the monitoring period in the two groups that received poloxamer 188 (numbers of animals alive after 3 hours = 7 of 8 in the High group and 6 of 8 in the Low group) compared to the Transfusion (4 of 8) and Volume (2 of 8) groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗