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L R Wasserman

Publications and source records attributed to L R Wasserman.

At least 19 recordsLinked to original sources
PubMed1997

Polycythemia vera: a retrospective and reprise.

This article, by two of the late John H. Lawrence's fellows of the 1940s, traces the development of the knowledge of polycythemia vera from Vaquez, who wrote the first description of this disease, and Osler, who recognized it as "a new clinical entity," through John H. Lawrence and the use of 32P as a treatment for polycythemia vera, to the formation of French and Italian polycythemia study groups. In particular, the history of polycythemia vera after the Second World War, and its more recent history, can be traced through the development of an algorithm for evaluating an elevated hematocrit and the development of the first (O1) protocol of the Polycythemia Vera Study Group (PVSG), a randomized trial of the efficacy of 32P, chlorambucil, and phlebotomy for treating polycythemia vera. It was in 1948, only 9 years after the first use of 32P for treating polycythemia vera, that Byron Hall reported the occurrence of acute leukemia following this use of the isotope. This led to the formation of the PVSG. After completing enrollment of patients in the first protocol of the PVSG, an attempt to find a replacement for 32P as a myelosuppressive agent led to the testing of hydroxyurea as a putative non-leukemogenic drug for this purpose. However, the use of hydroxyurea for treating polycythemia vera is coming into question, as is the ability to maintain patients with phlebotomy alone. The PVSG as such no longer exists as an operational group; its files are maintained at the Mount Sinai School of Medicine in New York City. However, the French group created for the study of polycythemia vera has had a consensus conference, and the Italian group has developed a low-dose aspirin protocol for treating the disease.

Aspirin↗
PubMed1987

Differentiation between essential thrombocythemia and polycythemia vera with marked thrombocytosis.

Accurate distinction between essential thrombocythemia and thrombocytotic polycythemia vera requires determination of the red cell mass in the presence of adequate iron stores, but this is not always possible. We therefore compared the clinical and laboratory features at the time of presentation of 50 patients with unequivocal essential thrombocythemia and 27 patients with thrombocytotic polycythemia vera. Univariate analysis failed to identify any single parameter capable of reliably separating the groups. A logistic regression algorithm incorporating hematocrit, white cell count, and spleen size markedly increased the diagnostic accuracy (92%) compared with predictions based on the hematocrit alone (52%). The algorithm's usefulness for patients with intermediate hematocrits was confirmed by analysis of independent samples of essential thrombocythemia and thrombocytotic polycythemia vera patients, and also by analysis of patients with probable essential thrombocythemia in whom the diagnosis could not be confirmed because of inadequate exclusion of polycythemia vera. Furthermore, comparison of survival data suggests that differentiating these disorders is prognostically important. The algorithm is recommended as an alternate method for differentiating essential thrombocythemia from thrombocytotic polycythemia vera whenever the red cell mass is unavailable or iron deficiency cannot be excluded.

Adult↗
PubMed1986

Therapeutic recommendations in polycythemia vera based on Polycythemia Vera Study Group protocols.

The PVSG was organized in 1967 to establish effective diagnostic criteria for polycythemia vera, to study the natural history of the disease and to define the optimal treatment. Although polycythemia vera and the other myeloproliferative diseases are relatively uncommon, the PVSG was able to accumulate well over 1,000 patients with these various disorders and to study them according to a total of 15 different protocols. PVSG-01, a long-term randomized controlled study of phlebotomy alone compared with the myelosuppressive agents, 32P or chlorambucil supplemented by phlebotomy, continues to receive follow-up data on 93% of surviving patients 18 years after initiation of the study. During its lifetime, PVSG has developed a widely accepted and highly effective set of criteria for the specific diagnosis of polycythemia vera as well as useful criteria for the diagnosis of essential thrombocythemia. It has gathered an enormous volume of data on the natural history of the myeloproliferative diseases and in particular on the nature of the prevalent complications, such as thrombotic events and hematologic and nonhematologic malignancies. With respect to the final question, the optimal treatment for polycythemia vera, it is apparent that the expectation of a single optimal therapy that would apply to all patients at all ages and stages of the disease was naive. Nevertheless considerable progress has been made. Moreover, the group has defined more precisely than ever before the nature of the complications of the disease and the association of the risks of specific complications with specific forms of therapy. It thus has made it possible to pose the next series of therapeutic questions that must be addressed in this disorder with a greater degree of sophistication than was previously possible.

Acute Disease↗
PubMed1984

Increased prevalence of polycythemia vera in parents of patients on polycythemia vera study group protocols.

An investigation of relatives of 652 patients entered on studies of the Polycythemia Vera Study Group yielded five documented cases of the disease among the parents of patients. When compared with expected values based on the Connecticut Tumor Registry and other population studies a significant increase was found in the lifetime incidence of polycythemia vera in parents of these patients.

Adult↗
PubMed1983

Leukemia-associated antigens in leukemic transformation of polycythemia vera.

Studies were made to test immune reactivity between anti-leukemic cell sera and nonadherent peripheral blood cells from patients with leukemic and nonleukemic P. vera. Cells from seven patients with leukemic P. vera had complement-dependent cytotoxicity test results showing more than 80% cell killing. In comparison, leukocytes from 37 nonleukemic and nonpolycythemic subjects, with and without blood disorders, failed to show significant cytotoxicity. Cells from 20 patients with nonleukemic P. vera and 10 patients with myelofibrosis, thrombocythemia, and "spent" P. vera also failed to react. Three nonleukemic P. vera patients showed a positive reaction that became progressively stronger; they developed leukemia at a later date. The association of positive reactivity before leukemia is overt, to later development of acute leukemia calls attention to the possible use of immunologic technology as a means of early diagnosis of leukemia.

Aged↗
PubMed1981

Increased incidence of acute leukemia in polycythemia vera associated with chlorambucil therapy.

In studies to determine the optimal treatment for polycythemia vera, 431 previously untreated patients whose disease met established diagnostic criteria were entered into a prospective, randomized controlled trial between 1967 and 1974. Three treatment regimens were used: phlebotomy alone, chlorambucil supplemented by phlebotomy, or radioactive phosphorus supplemented by phlebotomy. Despite minor differences in age and sex, the three groups were comparable in initial hematocrit, white-cell and platelet counts, and disease-related symptoms. The median duration of follow-up is now more than 6 1/2 years. As of February 15, 1980, there were no statistically significant differences in survival among the groups. However, the risk of acute leukemia in patients given chlorambucil was 2.3 times that in patients given radioactive phosphorus and 13 times that in patients treated with phlebotomy alone. The increased incidence of leukemia during chlorambucil treatment is statistically significant (P less than or equal to 0.002); accordingly, the Polycythemia Vera Study Group has discontinued the use of chlorambucil in the treatment of polycythemia vera.

Acute Disease↗
PubMed1979

Fetal hemoglobin in polycythemia vera: cellular distribution in 50 unselected patients.

Fetal hemoglobin was studied in 50 unselected patients with polycythemia vera with chemical determinations of Hb F and measurements of F-cell levels using fluorescent anti-Hb F antibodies. Although in the majority of the patients Hb F production did not differ from that in normal controls, in 20% of the patients F-cell values were above the normal range. There was no correlation between F-cell values and duration of disease, treatment modality, presence of myelofibrosis, or hematologic parameters at the time of study. In 5 of 50 patients 30%--45% of the erythrocytes contained Hb F; such striking elevations of F cells may reflect a distorted differentiation of erythroid precursor cells in certain patients with this disorder.

Erythrocytes↗
PubMed1977

Suppression of erythroid-colony formation by lymphocytes from patients with aplastic anemia.

To explore the possible role of cell-mediated suppression of erythropoiesis in acquired aplastic anemia, we studied the effect of peripheral blood lymphocytes from seven patients with aplastic anemia on erythroid-colony formation by normal human bone marrow in an in vitro plasma clot-culture system. Varying numbers of peripheral blood lymphocytes (0.5 to 6 X 10(5) cells) were cocultured with 6 X 10(5) normal bone-marrow cells in the presence of 2 IU of erythropoietin for seven days. Peripheral blood lymphocytes from five of the seven patients with aplastic anemia caused a 79 to 94 per cent reduction of erythroid-colony formation. Thus, at a peripheral blood lymphocyte concentration of 2 X 10(5) cells, the numbers of erythroid colonies formed (control vs. experimental) were 374 +/- 16 (S.E.M.) vs. 22 +/- 6, 48 +/- 4, 50 +/- 16, 80 +/- 4 and 27 +/- 3. These results suggest that some patients with aplastic anemia possess a population of lymphocytes capable of suppressing in vitro erythropoiesis.

Adolescent↗
PubMed1977

Erythroid colony formation by polycythemia vera bone marrow in vitro. Dependence on erythropoietin.

In the plasma clot culture system both normal and polycythemia vera (PV) bone marrow cells respond to erythropoietin (Ep), giving rise to large numbers of colonies of erythroid cells. In PV, but not in normal individuals, the marrow produced endogenous erythroid colonies (EED) in the absence of exogenous Ep. The number of EEC formed varied from patient to patient comprising anywhere from 6 to 29% of the total number of colonies formed in the presence of Ep. Exposure, before use in culture, of fetal calf serum and citrated bovine plasma to the gammaglobulin fraction of rabbit anti-Ep serum followed by treatment with goat anti-rabbit gamma-globulin re sulted in a significant decrease in EEC formation. Addition of anti-Ep directly to the culture medium produced similar results. In addition, the production of EEC in response to added Ep was inhibited in the presence of anti-Ep. Addition of very small doses of highly purified Ep to anti-Ep-treated cultures resulted in the reappearance of a significantnumber of EEC formation in PV may be due to a population of erythroid-committed precursors that are abnormally sensitive to small concentrations of Ep which may be present in fetal calf serum and citrated plasma. Although the mechanism of formation of these cells is not known, it appears that the final steps in the formation of red cells derived from this clone of precursors is subject to the usual Ep control.

Adult↗
PubMed1977

Liver as the primary site of erythropoietin formation in the fetus.

Fetal sheep produced significant amounts of erythropoietin in response to bleeding. Bilateral nephrectomy prior to bleeding failed to influence the formation of erythropoietin. Removal of the spleen, in addition to kidneys, was also without effect. Subtotal hepatectomy prior to bleeding, however, inhibited erythropoietin formation in these fetuses. In situ perfusion of the liver, but not the kidney, resulted in the appearance of significant quantities of the hormone in the perfusate. These results suggest that the liver is the primary site of erythropoietin production in the mammalian fetus.

Animals↗