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Dive into the research topics where Albert Roy is active.

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Featured researches published by Albert Roy.


Transfusion | 1973

Prophylactic Platelet Transfusions in Children with Acute Leukemia: A Dose Response Study

Albert Roy; N. Jaffe; Isaac Djerassi

A study of the value of small doses of platelets given prophylactically in thrombocytopenic patients was carried out. Transfusions of two dose levels of platelets were compared: 0.03 units/1b (low dose) and 0.06 units/lb of body weight (high dose). The incidence of bleeding in nontransfused patients seen here prior to this study was also determined. The difference in incidences of bleeding among patients transfused with low or high dose was not significant. The differences between the transfused and nontransfused patients were highly significant.


Experimental Biology and Medicine | 1972

Effects of platelet transfusions: plug formation and maintenance of vascular integrity.

Albert Roy; Isaac Djerassi

Summary Separate mechanisms of action account for the effects of platelets on maintenance of vascular endothelium and on bleeding from mechanically injured vessels. Circulating platelets in excess of 50,000/mm3 are needed in thrombocytopenic dogs to consistently reduce their bleeding time to normal levels. Significant reduction of red cell diapedesis into the lymph, an index of endothelial damage, was observed following transfusions of small amounts of platelets in the same animal model whether or not the platelet count was increased. The known dependence of the bleeding time on “hemostatic plug” formation suggests that higher levels of circulating platelets are needed for its adequate formation, while small numbers of functional platelets may be needed to support the integrity of vascular endothelium. Since endothelial changes appear to account for initiating spontaneous bleeding and lack of hemostatic plug formation for its continuation, various programs of platelet replacement may be needed by thrombocytopenic individuals requiring prophylactic or therapeutic platelet transfusions.


Transfusion | 1968

Transfusion of Fresh Platelet Concentrates to Adult Patients with Thrombocytopenia

J. Cavins; S. Farber; Albert Roy

Fresh platelet concentrates were given to 18 adult patients on 68 occasions without adverse effect. The concentrates were prepared by means of a closed‐system plateletpheresis technic which permitted rapid and frequent bleeding of donors. There was a direct relationship of the amount of platelets infused to the mean posttransfusion increment. Excellent hemostatic effect was noted in 84% of patients with active bleeding when the platelet increment was 40,000/mm3 or better. Transfusion of large numbers of platelet concentrates is effective in controlling or averting bleeding in adults with thrombocytopenia and is recommended on a therapeutic and prophylactic basis.


Transfusion | 1971

Dimethylacetamide, a New Cryoprotective Agent for Platelets

I. Djerassi; Albert Roy; J. S. Kim; J. Cavins

Dimethylacetamide (DMAC) was used as cryoprotective agent for the preservation of platelets in the frozen state. The addition of dextrose to the platelet suspension greatly increased the cryoprotective effects of this agent. Rat platelets preserved with 5 per cent DMAC and 5 per cent dextrose showed a higher percentage of morphologically intact cells and higher clot retraction‐promoting activity than platelets frozen in other concentrations of these two agents. The infusion of these platelets into thrombocytopenic rats resulted in platelet‐count increments greater than those observed after administration of platelets frozen in 5 per cent dimethylsulfoxide (DMSO) and 5 per cent dextrose. At room temperatures, DMAC appeared to be less damaging to platelets than DMSO. Transfusions of human platelets frozen with DMAC and dextrose to thrombocytopenic patients with acute leukemia were associated with temporary increases of their platelet counts.


Life Sciences | 1963

Some effects of laser radiation on the skin of the Syrian hamster

S. Fine; E. Klein; R.E. Scott; R. Seed; Albert Roy

Abstract In preliminary studies Syrian hamsters were exposed to radiation emitted by a laser utilizing a neodymium-doped glass rod. Lasered beams at 30 joule and 50 joule were focussed onto the surface of the anterior abdominal wall and of the exteriorized cheek pouch. Lesions resembling thermal burns were induced. The animals showed no other ill effects. Current studies deal with the manner in which dyes may modify the effects of lasered radiation, and with the actions of lasered radiation of higher intensities.


Transfusion | 1970

Circulation of Concentrated One-day-old Platelets in Vivo

Albert Roy; J. Cavins; I. Djerassi

Platelet concentrates of rat and human origin were stored at 22 C or at 4 C for up to 24 hours without additives. Transfusion of these concentrates into thrombocytopenic recipients demonstrated that: (1) storage of rat or human platelets at 4 C for up to 24 hours did not affect their recovery in vivo; (2) storage at 22 C resulted in a marked reduction in the viability of rat platelets but only a slight reduction in the viability of human platelets as adjudged by these criteria; (3) at 24 hours posttransfusion, the residual increment of platelets stored at 22 C was significantly higher than that of platelets stored at 4 C. The pH of the concentrates (rat and human) stored at 4 C remained slightly alkaline while the pH of those stored at 22 C., especially rat platelets, was significantly reduced. The deleterious effects of storage of platelets at 4 C are well known. These effects, however, do not preclude their usefulness when a limited objective of arresting or preventing hemorrhage for short periods is pursued. When daily platelet transfusions are feasible, platelets stored for 24 hours at 4 C in the absence of fresh material are adequate for clinical use.


Journal of Clinical Investigation | 1962

EFFECTS OF SOYBEAN PHOSPHATIDES ON THE HEMORRHAGIC TENDENCY DUE TO THROMBOCYTOPENIA

Issac Djerassi; Sidney Farber; Albert Roy; Hiroku Yoshimura

Intravenous administration of a soybean phosphatide preparation to x- irradiated, thrombocytopenic dogs was followed by rapid reduction of bleeding into the lymph of the left thoracic lymph duct. The maximal effects of a single infusion lasted 2 to 3 hours, but could be maintained or induced again by subsequent infusions. Complete return of the lymph to norraal appearance and content of red blood cells was observed in some of the animals. The prolonged bleeding time was not affected. (auth)


Experimental Biology and Medicine | 1962

HEMOSTATIC EFFECTS OF HETEROLOGOUS PLATELETS IN THROMBOCYTOPENIC RATS

Albert Roy; Hiroku Yoshimura; Isaac Djesassi

Summary Fresh human platelets transfused into thrombocytopenic rats are removed from the circulation within 2 to 3 hours. The output of red blood cells into the lymph is reduced (-70%) despite the declining platelet count. The effects of fresh rat platelets are both more marked and more consistent. Species-specificity may perhaps account for the lesser activity of heterologous platelets.


Circulation Research | 1962

Effects of Hemorrhagic Shock on Vascular Permeability to Red Blood Cells

Isaac Djerassi; Albert Roy

The lymph collected from the left thoracic lymph duct of dogs in severe shock due to blood loss becomes grossly hemorrhagic. Reversible hemorrhagic shock is not accompanied by changes in lymph appearance or content of red blood cells. The increased levels of red cells in the lymph was observed prior to the appearance of the characteristic gross intestinal and peritoneal hemorrhages.


Blood | 1963

A Method for Preservation of Viable Platelets: Combined Effects of Sugars and Dimethylsulfoxide

Isaac Djerassi; Albert Roy

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Isaac Djerassi

National Foundation for Cancer Research

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J. Cavins

National Foundation for Cancer Research

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S. Fine

Northeastern University

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Hiroku Yoshimura

National Foundation for Cancer Research

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I. Djerassi

National Foundation for Cancer Research

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R. Seed

Northeastern University

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R.E. Scott

Northeastern University

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Edmund Klein

National Foundation for Cancer Research

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Isaac Djesassi

National Foundation for Cancer Research

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