Opposite effects of ethanol on the activation of adenylyl cyclase in human corpus luteum membranes

The influence of an acute exposure to ethanol on adenylyl cyclase activity in membrane fractions prepared from human corpus luteum was investigated. Ethanol up to a concentration of 5% (v/v) was without effect on basal luteal adenylyl cyclase activity, but markedly potentiated stimulation of NaF and hCG in a dose-dependent manner. In contrast, ethanol progressively inhibited forskolin stimulation at the same range of ethanol concentrations. Maximal NaF and hCG responsiveness of adenylyl cyclase activity was observed at 5% ethanol and reached values 80% and 100% higher than controls without ethanol, respectively. However, at the same ethanol concentration, forskolin-stimulated enzymatic activity was reduced by 40% relative to controls. Equilibrium binding studies involving [¹²⁵I]hCG interaction with luteal membranes in the presence of the concentration of ethanol showing maximal hCG responsiveness indicated that ethanol slightly affected (15% increase) the hCG binding compared to controls, without any appreciable change on the K_d for the hormone. This minor effect of ethanol on gonadotropin binding sites contrasted greatly with the extent at which ethanol maximally potentiated the gonadotropin-stimulated adenylyl cyclase. GTP was found to be less effective than GMP-P(NH)P in sustaining ethanol potentiation, suggesting that ethanol is unlikely to act by inhibiting GTPase activity. These data indicate that the acute effects of ethanol inhibit forskolin-stimulated adenylyl cyclase at concentrations potentiating stimulatory effects of NaF and of hCG, and that the synergistic interaction of ethanol and gonadotropin stimulation of adenylyl cyclase is, at least in part, due to an increase in the functional coupling of the occupied hCG-receptor complex with the components of the enzyme system.     

Transforming growth factor beta inhibits endomitosis in the Dami human megakaryocytic cell line

Megakaryocyte development is a carefully controlled process that is at least partially regulated by cytokines. Previous investigations of megakaryocyte development have focused primarily on defining growth factors that induce or enhance differentiation. In this study we demonstrate that a specific cytokine, transforming growth factor beta 1 (TGF beta 1), inhibits the phorbol myristate acetate (PMA)-induced differentiation of the Dami human megakaryocytic cell line. The addition of purified platelet TGF beta 1 inhibits PMA-induced endomitosis in a dose-dependent manner. Inhibition of endomitosis occurs with as little as 0.4 pmol/L TGF beta 1, is half-maximal at 6.4 pmol/L, and is maximal between 40 and 200 pmol/L TGF beta 1. Inhibition does not require other growth factors or nonmegakaryocytic cells. Removal of TGF beta 1 from the cultures decreases inhibition, suggesting that the continuous presence of TGF beta 1 is required and that its effects are reversible. This effect occurs even though the Dami cells constitutively express TGF beta 1 messenger RNA (mRNA) and the TGF beta 1 mRNA levels are increased by PMA. TGF beta 1 also has been shown to inhibit endomitosis during short-term culture of primary human megakaryocytes. These results suggest a model in which negative as well as positive regulatory factors modulate a critical stage of megakaryocyte development.     

Successful treatment of JMML relapsed after unrelated allogeneic transplant with cytoreduction followed by DLI and interferon-alpha: evidence for a graft-versus-leukemia effect in non-monosomy-7 JMML

Relapse is the major cause of treatment failure after allogeneic transplantation of children with juvenile myelomonocytic leukemia (JMML), and the role of post-transplant immunomodulation is poorly understood. We report a 12-month-old child with JMML relapsed after unrelated marrow transplantation who received cytoreduction followed by donor lymphocyte infusion (DLI) with improvement, and after addition of interferon-alpha (IFN) achieved complete donor chimerism. He was weaned from IFN and has maintained complete remission for 19 months. This is the first published report of a patient with non-monosomy-7 JMML responding to post-transplant immunomodulation and suggests a role for DLI plus IFN in these patients.     

The Relationship Between Multimorbidity and Patients’ Ratings of Communication

BACKGROUND  The growing interest in pay-for-performance and other quality improvement programs has generated concerns about potential performance measurement penalties for providers who care for more complex patients, such as patients with more chronic conditions. Few data are available on how multimorbidity affects common performance metrics. OBJECTIVE  To examine the relationship between multimorbidity and patients’ ratings of communication, a common performance metric. DESIGN  Cross-sectional study SETTING  Nationally representative sample of U.S. residents PARTICIPANTS  A total of 15,709 noninstitutionalized adults living in the United States participated in a telephone interview. MEASUREMENTS  We used 2 different measures of multimorbidity: 1) “individual conditions” approach disregards similarities/concordance among chronic conditions and 2) “condition-groups” approach considers similarities/concordance among conditions. We used a composite measure of patients’ ratings of patient–physician communication. RESULTS  A higher number of individual conditions is associated with lower ratings of communication, although the magnitude of the relationship is small (adjusted average communication scores: 0 conditions, 12.20; 1–2 conditions, 12.06; 3+ conditions, 11.90; scale range 5 = worst, 15 = best). This relationship remains statistically significant when concordant relationships among conditions are considered (0 condition groups 12.19; 1–2 condition groups 12.03; 3+ condition groups 11.94). CONCLUSIONS  In our nationally representative sample, patients with more chronic conditions gave their doctors modestly lower patient–doctor communication scores than their healthier counterparts. Accounting for concordance among conditions does not widen the difference in communication scores. Concerns about performance measurement penalty related to patient complexity cannot be entirely addressed by adjusting for multimorbidity. Future studies should focus on other aspects of clinical complexity (e.g., severity, specific combinations of conditions).     

Analysis of megakaryocyte ploidy in rat bone marrow cultures

Megakaryocytes undergo changes in ploidy in vivo in response to varying demands for platelets. Attempts to study the putative factor(s) regulating these ploidy changes have been frustrated by the lack of an appropriate in vitro model of megakaryocyte endomitosis. This report describes a culture system in which rat bone marrow is depleted of identifiable megakaryocytes and enriched in their precursor cells. Morphologically identifiable megakaryocytes appear when the depleted marrow is cultured in vitro. The total number of nucleated cells, as well as the number of megakaryocytes and their ploidy distribution, are quantitated very precisely by flow cytometry. Although the total number of nucleated cells declines by 35% to 40% over 3 days in culture, the number of megakaryocytes rises 10-fold. The number of nucleated cells, the number of megakaryocytes, and the extent of megakaryocyte ploidization behave as independent variables in culture and are dependent on the culture conditions. The addition of recombinant erythropoietin promotes a rise in the number of megakaryocytes and a shift in ploidy to higher values while recombinant murine granulocyte- macrophage colony stimulating factor is without effect on the cultured megakaryocytes. This in vitro system may provide a means to study those factors that affect megakaryocyte growth and ploidization.     

Thrombasthenia with an abnormal platelet membrane glycoprotein IIb of different molecular weight

We describe an individual with abnormal platelet glycoprotein (GP) IIb of different molecular weight (mol wt), a defect that distinguishes this patient from previously reported thrombasthenics. The patient, a 21-year-old female, has a mild bleeding tendency; her platelets lack adenosine diphosphate (ADP) aggregation and have severely suppressed collagen aggregation but a normal response to ristocetin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of her platelets indicates that they contain two types of GPIIb molecules: one with an abnormal mol wt (122 kd, unreduced; 128 kd, reduced) and one with a normal mol wt (128 kd, unreduced; 118 kd, reduced). Relative to the amount of GPIIb in normal platelets, her platelets contain approximately 35% abnormal GPIIb and 20% normal GPIIb. Fibrinogen binding assays on the patient's platelets indicated that they contained 25% of the normal amount of fibrinogen receptors. Crossed immunoelectrophoresis of the patient's platelets demonstrated the formation of a GPIIb/IIIa complex that was mainly composed of normal mol wt GPIIb and GPIIIa. The patient's father has decreased ADP aggregability, and his platelets also contained both abnormal and normal GPIIb (about 50% of the normal level and about 50% of the normal number of fibrinogen receptors); her mother has only normal GPIIb. These results indicate that the patient has heterozygous GPIIb molecules with an abnormality of GPIIb at the molecular level. Studies on this abnormal GPIIb should provide information about the function of GPIIb and the mechanism of its biosynthesis.     

Divergent molecular phenotypes of KG1 and KG1a myeloid cell lines

The cell line KG1 derived from a patient with erythroleukemia in myeloblastic relapse has the composite phenotype and functional repertoire of myeloblasts. In marked contrast, its subline KG1a has lost myeloid features, acquired new karyotypic markers, and has three characteristics associated with immature T cells: low-level expression of the T cell receptor beta mRNA (but not alpha) transcribed from a germline gene; high-level expression of T3 delta mRNA and intracellular, but not cell surface, T3 protein; and expression of the CD7/gp40 T cell-associated membrane antigen. Both KG1 and KG1a transcribe unrearranged IgH genes. These data suggest that either the KG1 cell line was derived from a common myeloid-lymphoid progenitor or that the KG1a subline phenotype is aberrant.