Randomized phase-III study of low-dose cytarabine and etoposide + /- all-trans retinoic acid in older unfit patients with NPM1-mutated acute myeloid leukemia

The aim of this randomized clinical trial was to evaluate the impact of all-trans retinoic acid (ATRA) in combination with non-intensive chemotherapy in older unfit patients (> 60 years) with newly diagnosed NPM1-mutated acute myeloid leukemia. Patients were randomized (1:1) to low-dose chemotherapy with or without open-label ATRA 45 mg/m2, days 8-28; the dose of ATRA was reduced to 45 mg/m2, days 8-10 and 15 mg/m2, days 11-28 after 75 patients due to toxicity. Up to 6 cycles of cytarabine 20 mg/day s.c., bid, days 1-7 and etoposide 100 mg/day, p.o. or i.v., days 1-3 with (ATRA) or without ATRA (CONTROL) were intended. The primary endpoint was overall survival (OS). Between May 2011 and September 2016, 144 patients (median age, 77 years; range, 64-92 years) were randomized (72, CONTROL; 72, ATRA). Baseline characteristics were balanced between the two study arms. The median number of treatment cycles was 2 in ATRA and 2.5 in CONTROL. OS was significantly shorter in the ATRA compared to the CONTROL arm (p = 0.023; median OS: 5 months versus 9.2 months, 2-years OS rate: 7% versus 10%, respectively). Rates of CR/CRi were not different between treatment arms; infections were more common in ATRA beyond treatment cycle one. The addition of ATRA to low-dose cytarabine plus etoposide in an older, unfit patient population was not beneficial, but rather led to an inferior outcome.The clinical trial is registered at clinicaltrialsregister.eu (EudraCT Number: 2010-023409-37, first posted 14/12/2010).

Azacitidine and Venetoclax in Previously Untreated Acute Myeloid Leukemia

BACKGROUND

Older patients with acute myeloid leukemia (AML) have a dismal prognosis, even after treatment with a hypomethylating agent. Azacitidine added to venetoclax had promising efficacy in a previous phase 1b study.

METHODS

We randomly assigned previously untreated patients with confirmed AML who were ineligible for standard induction therapy because of coexisting conditions, because they were 75 years of age or older, or both to azacitidine plus either venetoclax or placebo. All patients received a standard dose of azacitidine (75 mg per square meter of body-surface area subcutaneously or intravenously on days 1 through 7 every 28-day cycle); venetoclax (target dose, 400 mg) or matching placebo was administered orally, once daily, in 28-day cycles. The primary end point was overall survival.

RESULTS

The intention-to-treat population included 431 patients (286 in the azacitidine-venetoclax group and 145 in the azacitidine-placebo [control] group). The median age was 76 years in both groups (range, 49 to 91). At a median follow-up of 20.5 months, the median overall survival was 14.7 months in the azacitidine-venetoclax group and 9.6 months in the control group (hazard ratio for death, 0.66; 95% confidence interval, 0.52 to 0.85; P<0.001). The incidence of complete remission was higher with azacitidine-venetoclax than with the control regimen (36.7% vs. 17.9%; P<0.001), as was the composite complete remission (complete remission or complete remission with incomplete hematologic recovery) (66.4% vs. 28.3%; P<0.001). Key adverse events included nausea of any grade (in 44% of the patients in the azacitidine-venetoclax group and 35% of those in the control group) and grade 3 or higher thrombocytopenia (in 45% and 38%, respectively), neutropenia (in 42% and 28%), and febrile neutropenia (in 42% and 19%). Infections of any grade occurred in 85% of the patients in the azacitidine-venetoclax group and 67% of those in the control group, and serious adverse events occurred in 83% and 73%, respectively.

CONCLUSIONS

In previously untreated patients who were ineligible for intensive chemotherapy, overall survival was longer and the incidence of remission was higher among patients who received azacitidine plus venetoclax than among those who received azacitidine alone. The incidence of febrile neutropenia was higher in the venetoclax-azacitidine group than in the control group. (Funded by AbbVie and Genentech; VIALE-A ClinicalTrials.gov number, NCT02993523.).

Randomized phase-II trial evaluating induction therapy with idarubicin and etoposide plus sequential or concurrent azacitidine and maintenance therapy with azacitidine

The aim of this randomized phase-II study was to evaluate the effect of substituting cytarabine by azacitidine in intensive induction therapy of patients with acute myeloid leukemia (AML). Patients were randomized to four induction schedules for two cycles: STANDARD (idarubicin, cytarabine, etoposide); and azacitidine given prior (PRIOR), concurrently (CONCURRENT), or after (AFTER) therapy with idarubicin and etoposide. Consolidation therapy consisted of allogeneic hematopoietic-cell transplantation or three courses of high-dose cytarabine followed by 2-year maintenance therapy with azacitidine in the azacitidine-arms. AML with CBFB-MYH11, RUNX1-RUNX1T1, mutated NPM1, and FLT3-ITD were excluded and accrued to genotype-specific trials. The primary end point was response to induction therapy. The statistical design was based on an optimal two-stage design applied for each arm separately. During the first stage, 104 patients (median age 62.6, range 18-82 years) were randomized; the study arms PRIOR and CONCURRENT were terminated early due to inefficacy. After randomization of 268 patients, all azacitidine-containing arms showed inferior response rates compared to STANDARD. Event-free and overall survival were significantly inferior in the azacitidine-containing arms compared to the standard arm (p < 0.001 and p = 0.03, respectively). The data from this trial do not support the substitution of cytarabine by azacitidine in intensive induction therapy.

The Influence of Thrombin on the Clotting Activity of Factor VIII. A Study with Insolubilized Thrombin

An investigation of the influence of thrombin on the clotting activity of factor VIII was made. Purified factor VIII and different amounts of thrombin complexed to Sepharose 4 B were mixed and incubated for various periods of time. The factor VIII activities of these incubation mixtures were determined by the one- and two-stage analytical procedures in the presence of the thrombin-sepharose and in its absence following the latter removal from the test sample by filtration. The results so obtained confirm the view that thrombin inactivates factor VIII. Evidences for a thrombin-induced potentiation of the factor VIII activity, seen only in the thrombin-sepharose containing test samples analyzed by the one-stage method, are here interpreted as thrombin-effects peculiar to this factor VIII test system and not as potentiation by thrombin of the factor itself.

Clozapine-associated diabetes

Clozapine is a potent antipsychotic agent that has been marketed since 1990. Several published reports of diabetes mellitus occurring with clozapine therapy have appeared during the past 5 years. Because the risk and characteristics of clozapine-associated diabetes mellitus remain unclear, we conducted a descriptive epidemiologic study of spontaneous adverse event reports of hyperglycemia occurring in clozapine-treated patients. The Food and Drug Administration MedWatch surveillance program was queried (January 1990 through February 2001), and the results were pooled with published cases. Parameters assessed included documentation of diabetes, clinical severity, new-onset diabetes versus exacerbation of preexisting disease, demographic characteristics of patients, time to onset of hyperglycemia, and effect of drug discontinuation and rechallenge. We identified 384 reports. Of these, new-onset diabetes was diagnosed definitively in 242 patients, and 54 patients had exacerbation of preexisting disease. The mean (+/- SD) age was 40 +/- 12 years (range, 13 to 77). The male:female ratio was 2:0. Most cases appeared within 6 months of initiating clozapine therapy. One patient developed diabetes following a single 500-mg dose. There were 80 cases of metabolic acidosis or ketosis. Twenty-five patients died during hyperglycemic episodes. Forty-six patients had improved glycemic control after discontinuation or dose reduction of the drug.A causal relationship between clozapine and diabetes is suggested by the number of reports, the temporal relation to clozapine initiation, the relatively young age of the affected patients, and the prompt reversibility on withdrawal of the drug in some patients. The severity of reported cases ranged from mild glucose intolerance to diabetic ketoacidosis or hyperosmolar coma.

Myelodysplastic syndromes, from French-American-British to World Health Organization: comparison of classifications on 431 unselected patients from a single institution

In 1999 a working group of the World Health Organization (WHO) published a revised classification for myelodysplastic syndromes (MDS): RA, RARS, refractory cytopenia with multilineage dysplasia (RC+Dys), RAEB I and II, del (5q) syndrome, and MDS unclassifiable. Chronic myelomonocytic leukemia (CMML) and RAEB-t were excluded. Standard French-American-British (FAB) and new WHO classifications have been compared in a series of patients (n = 431) from a single center, analyzing morphologic, clinical, and cytogenetic data. According to the WHO findings, dysgranulocytopoiesis or dysmegakaryocytopoiesis only were found in 26% of patients with less than 5% medullary blasts. These patients are thus unclassified and should remain in the subgroups RA and RARS. Splitting of heterogeneous RAEB into 2 subgroups according to blast count was supported by a trend to a statistically significant difference in the single-center study population. Patients with CMML whose white blood cell counts are above 13 000/microL may be excluded from the MDS classification, as warranted by WHO, but a redistribution of patients with dysplastic CMML according to medullary blast count leads to more heterogeneity in other WHO subgroups. Although the natural courses of RAEB-T and acute myeloid leukemia (AML) with dysplasia are different, comparable median survival durations after treatment in patients with RAEB-T and AML were in favor of the proposed 20% medullary blast threshold for AML. The homogeneity of subgroups was studied by evaluating prognostic scores. A significant shift into lower IPSS risk groups was evident in the new classification. These data cannot provide evidence for the new WHO proposal, which should not be adopted for routine clinical use at present. Some of its aspects can provide a starting point for further studies involving refined cytogenetics and clinical results.

Characterization of (123)I-vascular endothelial growth factor-binding sites expressed on human tumour cells: possible implication for tumour scintigraphy

To explore the possibility of vascular endothelial growth factor (VEGF) receptor scintigraphy of primary tumours and their metastases, we analysed the binding properties of (123)I-labelled VEGF(165) ((123)I-VEGF(165)) and (123)I-VEGF(121) to human umbilical vein endothelial cells (HUVECs), several human tumour cell lines (HMC-1, A431, KU812, U937, HEP-1, HEP-G2, HEP-3B and Raji), a variety of primary human tumours (n = 40) and some adjacent non-neoplastic tissues as well as normal human peripheral blood cells in vitro. Two classes of high-affinity (123)I-VEGF(165)-binding site were found on the cell surface of HUVECs. In contrast, one class of high-affinity binding sites for (123)I-VEGF(165) was found on HMC-1, A431, HEP-1, HEP-G2, HEP-3B and U937 cells as well as many primary tumours. For (123)I-VEGF(121), a single class of high-affinity binding site was found on certain cell lines (HUVEC, HEP-1 and HMC-1) and distinct primary tumours (primary melanomas, ductal breast cancers and ovarian carcinomas as well as meningiomas). Tumour cells expressed significantly higher numbers of VEGF receptors compared with normal peripheral blood cells and adjacent non-neoplastic tissues. Immunohistochemical staining revealed that the VEGF receptor Flk-1 is expressed to a much higher extent within malignant tissues compared with neighbouring non-neoplastic cells. We observed significantly greater specific binding of (123)I-VEGF(165) and (123)I-VEGF(121) to a variety of human tumour cells/tissues compared with the corresponding normal tissues or normal peripheral blood cells. In comparison with (123)I-VEGF(121), (123)I-VEGF(165) bound to a higher number of different tumour cell types with a higher capacity. Thus, (123)I-VEGF(165) may be a potentially useful tracer for in vivo imaging of solid tumours.

Effects of vasoactive intestinal peptide (VIP) and somatostatin (SST) on lipoprotein receptor expression by A431 tumor cells

A variety of tumor cells have been shown to express lipoprotein receptors. Recent data suggest that lipoprotein receptors may play a regulatory role in the growth of certain tumor cells. We investigated the effects of vasoactive intestinal peptide (VIP) and somatostatin-14 (SST-14) on the binding of 111Indium-labeled lipoproteins [(111)In-low density lipoprotein ((111)In-LDL), (111)In-high density lipoprotein ((111)In-HDL) and (111)In-very low density lipoprotein ((111)In-VLDL)] onto the epidermoid mammary carcinoma cell line A431. Scatchard analyses of the binding data indicated one class of specific high affinity binding sites for LDL, HDL and VLDL expressed by A431 cells, respectively. VIP increased significantly the binding capacity for (111)In-LDL on A431 cells. The VIP-induced increase of (111)In-LDL binding sites was inhibited by SST-14. Furthermore, SST-14 inhibited VIP-induced 3H-thymidine incorporation and adenosine 3'-5' cyclic monophosphate (cAMP) formation in A431 cells with IC50 values in the range of 5-7 nM. However, SST-14 showed no effect on dibutyryl-cAMP-induced increase of (111)In-LDL binding sites expressed on A431 cells. In contrast to (111)In-LDL binding, no effects of VIP or SST-14 on HDL or VLDL binding to A431 tumor cells were found. Our results suggest a direct effect of VIP and SST-14 on LDL-binding onto tumor cells. The complex interactions between VIP and SST-14 on LDL receptor expression of tumor cells may play a role in tumor cell lipid metabolism.

Discovery and analysis of antisense oligonucleotide activity in cell culture

In the past decade antisense oligonucleotides (ASOs) have proven to be a useful tool for dissection of gene function in molecular cell biology (Koller, E., Gaarde, W. A., and Monia, B. P. (2000) Trends Pharm. Sci., 21, 142-148), and validation of gene targets in animal models (Crooke, S. T. (1998) Biotechnol. Gen. Eng. Rev. 15, 121-157), as well as a means for therapeutic treatment of human diseases (Bennett, C. F. (1999) Exp. Opin. Invest. Drugs 8, 237-253). An important step toward usage of ASOs in the described applications is identification of an active ASO. This article describes the underlying basis and means for achieving this goal in cell culture.

Inhibition of inducible nitric oxide synthesis by the herbal preparation Padma 28 in macrophage cell line

Padma 28 is a mixture of herbs used in traditional Tibetan medicine with anti-inflammatory activities. We investigated the effects of Padma 28 on nitric oxide (NO) production by the inducible nitric oxide synthase (iNOS) in lipopolysaccharide stimulated mouse macrophages (RAW 264.7). Padma 28 (0-900 microg/mL) induced a concentration dependent inhibition of inducible nitric oxide synthesis. iNOS protein expression showed a concentration dependent reduction as revealed by immunoblotting when cells were incubated with increasing amounts of Padma 28. Padma 28 decreased iNOS mRNA levels as shown by RT-PCR. Aqueous extracts from costi amari radix (costus root, the dried root of Saussurea lappa) and the outer cover of myrobalani fructus (the dried fruit of Terminalia chebula), constituents of the complex herb preparation Padma 28, were found to inhibit inducible nitric oxide synthesis by decreasing iNOS protein and iNOS mRNA levels. The inhibition of inducible nitric oxide synthesis might contribute to the anti-inflammatory activities of Padma 28.

Hypochlorite modified LDL are a stronger agonist for platelets than copper oxidized LDL

Experimental low density lipoprotein (LDL) oxidation is usually performed using trace copper, although the in vivo relevance of this method has been called into question. Such LDL augment adenosine 5'-diphosphate (ADP) induced platelet aggregation, presumably by the action of lipid derived compounds. In striking contrast, we find that LDL oxidized to a comparable extent by hypochlorite, an in vivo occurring oxidant, reveal themselves to be potent promoters of platelet aggregation. Interestingly, hypochlorite modified LDL seem to mediate their influence on human platelets by means of the modified apolipoprotein B-100 (apoB) moiety. Also, the finding that hypochlorite modified albumin is able to trigger platelet aggregation suggests an essential role for hypochlorite modified protein(s) in the process of platelet activation.

Aseptic necrosis in HIV seropositive patients: a possible etiologic role for megestrol acetate

The association between pharmacologic doses of corticosteroids and the development of aseptic bone necrosis has been well documented. Recent reports have described the corticosteroid activity of megestrol acetate. A retrospective review of adverse events reported to the U.S. Food and Drug Administration identified three human immunodeficiency virus (HIV) seropositive patients who developed avascular necrosis of the femoral head during treatment with megestrol acetate. All were males, ages 34, 36, and 55 years, and were on therapy for 6, 1.5, and 18 months, respectively, when symptoms of aseptic necrosis occurred in the absence of antecedent trauma. Megestrol acetate doses were 640, 320, and 600-1200 mg/d, respectively. Two patients had no history of corticosteroid use whereas the third had taken an undisclosed dose and duration of corticosteroids concurrent with pentamidine administration. Notably, despite the predominant use of megestrol in women for hormone sensitive malignancies, none of the reports of aseptic necrosis occurred in this population. Megestrol acetate may be associated with the development of avascular necrosis via its glucocorticoid-like effects. Cachectic acquired immunodeficiency syndrome (AIDS) patients may have additional risk factors that predispose them to aseptic necrosis when receiving megestrol acetate.

Modification of protein moiety of human low density lipoprotein by hypochlorite generates strong platelet agonist

Conflicting reports exist about the effects of mildly or extensively oxidized low density lipoproteins (LDLs) on the reactivity of human platelets. This platelet response is mainly caused by modification of the protein and lipid moiety, giving rise to very differently modified species with hardly predictable properties. The aim of this study was to prepare oxidized LDL with modifications essentially restricted to the protein moiety and to determine the eventual platelet responses. We treated LDL at 0 degrees C for 10 minutes with a 60- to 1000-fold molar excess of sodium hypochlorite in borate buffer in the presence of the radical scavenger butylated hydroxytoluene. Under these conditions, neither fragmentation of apolipoprotein B-100 nor formation of LDL aggregates was observed, and lipid oxidation products did not exceed the amount present in untreated LDLs. The degree of modification and the respective effects on platelet function were highly reproducible. Hypochlorite-modified LDLs act as strong platelet agonists, inducing morphological changes, dense granule release, and irreversible platelet aggregation. The evoked platelet effects are completely suppressed by inhibitors of the phosphoinositide cycle but not by EDTA or acetylsalicylic acid. Most likely, these effects are transmitted via high-affinity binding to a single class of sites, which does not recognize native or acetylated LDL. Obviously, modified lysines, and the secondary lipid modifications derived from them, are not essential for this interaction. We conclude that bioactive oxidized lipids are not directly involved in the stimulation of platelets by hypochlorite-modified LDLs.

Inhibition of inducible nitric oxide synthesis by oxidized lipoprotein(a) in a murine macrophage cell line

Increased plasma levels of human lipoprotein(a) (Lp(a)) are highly correlated with the development of atherosclerotic lesions. During our study, we investigated the effects of native and hypochlorite oxidized lipoprotein(a) (ox-Lp(a)) on nitric oxide production by the inducible nitric oxide synthase (iNOS) in lipopolysaccharide/interferon stimulated mouse macrophages (J774A.1). Ox-Lp(a) (0-2 microg/ml) induces a dose dependent inhibition of inducible nitric oxide synthesis. iNOS protein expression showed a dose dependent reduction as revealed by immunoblotting when cells were incubated with increasing amounts of ox-Lp(a). Ox-Lp(a) decreases iNOS mRNA synthesis as shown by reverse transcription-polymerase chain reaction. Ox-Lp(a) induced iNOS inhibition might contribute to the development of atherosclerotic lesions by reducing the anti-atherogenic effects of nitric oxide.

Rapid characterization of complex structural phase transitions using powder diffraction and an area detector

The use of a high-intensity and well collimated X-ray beam from a third-generation synchrotron source, combined with an area detector with online readout capabilities, allows high-quality powder patterns to be obtained with exposure times of only a few seconds. Powder measurements of a rare-earth manganate perovskite (Nd(0.43)Sr(0.57)MnO(3)) were performed in the temperature range 105-200 K, and the data were of sufficient quality to be able to extract, via Rietveld refinement, accurate values for the lattice constants and atomic parameters. The temperature dependence of the Mn-O-Mn bond angles and Mn-O distances obtained in this manner illustrate the well known correlation between the distortion of the MnO(6) octahedra and the onset of orbital ordering. The success of this study, for which only two hours of synchrotron beam time was required, indicates the enormous improvements in efficiency and throughput which area detectors are bringing to powder diffraction experiments.

Elucidating cell signaling mechanisms using antisense technology

Many diseases result from defects in cell signaling. Achieving an in-depth understanding of the complex mechanisms by which cells transduce extracellular signals into cellular responses in both normal and diseased systems is a crucial step in the discovery of more effective drugs to treat human diseases. Traditional approaches for studying cell signaling have some limitations. Antisense oligonucleotides represent a novel approach for studying signal transduction processes that offers significant advantages in terms of specificity and versatility. This article reviews the opportunities that antisense oligonucleotides offer for the study of signal transduction pathways and identification of inhibitors of these pathways for drug development.

Stimulating effect of biologically modified low density lipoproteins on ADP-induced aggregation of washed platelets persists in absence of specific binding

Oxidized low density lipoproteins are closely associated with atherosclerosis and also might be directly involved in thrombosis because they have been shown to mediate a stimulating effect on human platelets. In this work, we used biologically modified low density lipoproteins (i.e., low density lipoproteins sufficiently oxidized to show specificity for the macrophage scavenger receptor system) to examine if specific binding of the oxidized apolipoprotein moiety to the platelet surface is a prerequisite for the platelet-stimulating effects reported by other authors. We find that biologically modified low density lipoproteins show specific binding to human platelets (K(d)=5.83+/-0.4 microg/mL, 3850+/-620 sites/platelet) and strongly augment both ADP- and thrombin-induced aggregation of washed platelets. Maleylated albumin, an antagonist of oxidized low density lipoproteins binding to all currently classified scavenger receptors, is able to reduce platelet oxidized low density lipoproteins binding to background levels. Nevertheless, maleylated albumin is not able to exert any kind of normalizing effect on the augmented ADP-induced aggregation response observed in the presence of biologically modified low density lipoproteins. From these data, we conclude that specific binding of oxidatively modified apolipoprotein B to the platelet surface is not essential to the process of platelet stimulation. Therefore, we conclude that these stimulating effects may be mediated by unidentified compounds formed in the lipid phase of the lipoproteins.

Urea induces macrophage proliferation by inhibition of inducible nitric oxide synthesis

BACKGROUND

Atherosclerosis is a major cause of morbidity and mortality in chronic renal failure and is associated with the proliferation of macrophages within atherosclerotic lesions.

METHODS

Because the progression of atherosclerosis as a consequence of decreased nitric oxide synthesis has been described, we investigated the correlation between the inhibition of inducible nitric oxide synthase (iNOS) by urea, macrophage proliferation as assayed by cell counting, tritiated thymidine incorporation and measurement of cell protein, and macrophage apoptosis.

RESULTS

Urea induces a dose-dependent inhibition of inducible nitric oxide synthesis in lipopolysaccharide-stimulated mouse macrophages (RAW 264.7) with concomitant macrophage proliferation. Macrophage proliferation, as determined by cell counting, became statistically significant at 60 mM urea, corresponding to a blood urea nitrogen level of 180 mg/100 ml, concentrations seen in uremic patients. iNOS protein expression showed a dose-dependent reduction, as revealed by immunoblotting when cells were incubated with increasing amounts of urea. The decrease of cytosolic DNA fragments in stimulated macrophages incubated with urea shows that the proliferative actions of urea are associated with a decrease of NO-induced apoptosis.

CONCLUSIONS

Our data demonstrate that the inhibition of iNOS-dependent NO production caused by urea enhances macrophage proliferation as a consequence of diminished NO-mediated apoptosis.

Unusual distributions of body fat in AIDS patients: a review of adverse events reported to the Food and Drug Administration

This report summarizes postmarketing adverse events reported to the Food and Drug Administration (FDA) that describe unusual or abnormal fat distribution in association with anti-retroviral therapies. Reports associated will protease inhibitors were compared to those associated with non-protease inhibitor antiretroviral therapies. The Spontaneous Reporting System (SRS) and Adverse Event Reporting System (AERS) of the FDA MEDWATCH post-marketing surveillance system served as the database. Four protease inhibitors (saquinavir, indinavir, nelfinavir, and ritonavir) and seven nonprotease inhibitors (zidovudine, didanosine, zalcitabine, stavudine, lamivudine, nevirapine, and delavirdine) were searched for reports relating to: weight increase, unusual fat deposition, Cushing's syndrome, or Cushingoid appearance. Each drug was searched for its "life" from time of initial approval through a uniform database cutoff of March 18, 1998. A total of 62 cases of abnormal fat accumulation were reported in association with one or several of the four approved protease inhibitors compared to three cases reported in association with the seven non-protease inhibitor based therapies. Case descriptions varied, and included abdominal fat accumulation, breast enlargement, thick necks, buffalo humps, multiple lipomatous growths, Cushingoid features, centralized fat redistribution, and mesenteric, omental, and retroperitoneal fat accumulation. Some subjects switched or stopped their antiretroviral therapy, others underwent surgery to remove the fat, and many considered their symptoms disabling. The pathophysiologic mechanism for these events remains unclear and a causal link to a specific drug or drug class is uncertain. Patients and clinicians reporting to the MEDWATCH system, however, have clearly associated the development of abnormal body fat with protease inhibitors as opposed to other antiretroviral therapies.

Human platelets exclusively bind oxidized low density lipoprotein showing no specificity for acetylated low density lipoprotein

The widely studied macrophage scavenger receptor system is known to bind both acetylated low density lipoprotein and oxidized low density lipoprotein. Although only the latter ligand has been shown to occur in vivo, acetylated low density lipoprotein is often used to evaluate the contribution of scavenger receptors to different (patho)physiologic processes, assuming that all existing subtypes of scavenger receptors recognise both lipoproteins. In the present work, we identify human platelets as the first natural cell type to bind oxidized low density lipoprotein without showing specificity for acetylated low density lipoprotein. Consequently, platelets possess exclusive receptor(s) for oxidized low density lipoprotein distinct from the 'classical' scavenger receptor AI/AII. From the data presented in this work, we conclude that the class B scavenger receptor CD36 (GPIV) is responsible for this exclusive oxidized low density lipoprotein binding.

Platelet high affinity low density lipoprotein binding and import of lipoprotein derived phospholipids

The binding of low density lipoprotein (LDL) to the platelet cell membrane could facilitate the transfer of phospholipids from LDL to the platelets. A polyclonal antibody against the platelet glycoproteins IIb/IIIa inhibited the high affinity binding of 125I-LDL by up to 80%. The transfer of pyrene (py)-labeled sphingomyelin (SM), phosphatidylcholine and phosphatidylethanolamine from LDL to the platelets was unaffected by the antibody. The lectin wheat germ agglutinin (WGA) reduced the binding of 125I-LDL to the platelets by approximately 80%. In contrast, the lectin stimulated the transfer of SM from LDL into the platelets by about three-fold. WGA also specifically augmented the transfer of py-SM between lipid vesicles and the platelets, the stimulation being abolished in the presence of N-acetylglucosamine. Dextran sulfate (DS) increased the specific binding of 125I-LDL to the platelets by up to 2.8-fold. On the other hand, the import of LDL-derived py-phospholipids was unaffected by DS. Together, the results indicate that the phospholipid transfer from LDL to the platelets is independent of the high affinity LDL binding to the platelets and is specifically stimulated by WGA. Thus, the interactions of platelets with LDL phospholipids differ markedly from those with the apoprotein components of the lipoproteins.

Modified LDL decreases the binding of prostaglandin E2, I2, and E1 onto monocytes in patients with peripheral vascular disease

Recent data suggest that various eicosanoids including prostaglandins play an important regulatory role in the development of atherosclerotic lesions. Peripheral blood monocytes have been implemented in early atherogenesis because they express receptors specific for modified LDL. In this study we investigated the binding of tritium prostaglandins E2 (3H-PGE2), E1 (3H-PGE1) and I2 (3H-PGI2) onto intact peripheral monocytes isolated from 20 patients (32-71 years) with manifested ischemic peripheral vascular disease stage II according to Fontaine and compared the results with those obtained in 16 healthy volunteers (21-68 years). In control subjects, Scatchard analyses of the binding data indicated a single class of high-affinity binding sites for 3H-PGE2 (maximal binding capacity [Bmax] = 11,400 +/- 3200 sites/cell; dissociation constant [Kd] = 1.3 +/- 0.5 nmol/L) and two classes of binding sites for 3H-PGE1 (Bmax1 = 11,200 +/- 4900 sites/cell, Kd1 = 1.5 +/- 0.5 nmol/L; Bmax2 = 47,800 +/- 6100 sites/cell, Kd2 = 12.8 +/- 5.9 nmol/L) as well as for 3H-PGI2 (Bmax1 = 10,100 +/- 3700 sites/cell, Kd1 = 1.7 +/- 0.7 nmol/L; Bmax2 = 81,200 +/- 5200 sites/cell, Kd2 = 14.2 +/- 6.5 nmol/L). In the patients, an absence of the higher-affinity binding class and significantly (P < .01) fewer lower-affinity binding sites were found for each ligand (PGE2: Bmax = 6600 +/- 3600 sites/cell, Kd = 12.1 +/- 3.2 nmol/L; PGI2: Bmax = 6400 +/- 3100 sites/cell, Kd = 22.1 +/- 8.3; PGE1: Bmax = 5300 +/- 1700 sites/ cell, Kd = 20.5 +/- 7.0 nmol/L). After incubation of monocytes with modified LDL (oxidized LDL or acetylated LDL), the binding of prostaglandins was significantly (P < .01 to P < .001) decreased, whereas native VLDL, LDL, and HDL did not interfere with prostaglandin binding. Prostaglandin-induced adenosine 3'-5' cyclic monophosphate (cAMP) formation by monocytes was significantly (P < .01) lower in patients (the concentrations causing 50% elevation of basal cAMP formation [ED50] were 3.8 +/- 2.4 nmol/L for PGE2, 6.3 +/- 3.5 nmol/L for PGE1, and 5.6 +/- 4.1 nmol/L for PGI2) than in the control subjects (ED50 was 1.6 +/- 1.2 nmol/L for PGE2, 4.8 +/- 2.5 nmol/L for PGE1, and 3.1 +/- 1.4 nmol/L for PGI2). After preincubation with modified LDL, the PG-induced cAMP production by monocytes was remarkably decreased in both patients and control subjects (P < .05). Our results suggest a direct effect of modified LDL on PGE2, PGE1, and PGI2 binding onto monocytes by reducing the number of cell surface-expressed receptors available. Modified LDL also reduces the sensitivity of monocytes to prostaglandins, which results in decreased cAMP production. The complex interactions between prostaglandins and lipoproteins may play an important role during atherogenesis.

Glucocorticoidlike activity of megestrol. A summary of Food and Drug Administration experience and a review of the literature

Sporadic single case reports linking glucocorticoidlike activity to megestrol acetate have been reported in the literature. These findings have important implications for patient care. Adverse drug experience reports to the US Food and Drug Administration from 1984 through 1996 and a MEDLINE search of the literature from 1984 through 1996 provided the case reports. Five cases of Cushing syndrome, 12 cases of new-onset diabetes, and 16 cases of adrenal insufficiency were identified in association with megestrol therapy. Twelve cases in which preexisting diabetes was exacerbated and 17 cases of possible adrenal insufficiency were identified. Therapy with megestrol can result in clinical manifestations of glucocorticoidlike activity, including Cushing syndrome, diabetes, and adrenal insufficiency. Clinicians need to be aware of this association as these complications can be life-threatening if not recognized.

Granulocyte colony-stimulating factor as an adjunct to induction chemotherapy for adult acute lymphoblastic leukemia--a randomized phase-III study

Because of the recommendation to avoid the concomitant administration of growth factors and chemotherapy, there is only limited information on colony-stimulating factor (CSF) therapy in acute lymphoblastic leukemia (ALL) induction protocols, in which cytotoxic drugs are administered in divided doses over a prolonged period of time, thus requiring a simultaneous administration of growth factors and chemotherapy. We conducted a prospective, randomized, controlled study to determine the safety and efficacy of granulocyte colony-stimulating factor (G-CSF; filgrastim) as an adjunct to phase I of induction chemotherapy for adult ALL. Patients (n = 53) were randomized to receive no growth factor or G-CSF (5 microg/kg/d subcutaneously) starting on day 2 of chemotherapy consisting of daunorubicin (45 mg/m2) and vincristine (1.5 mg/m2) on days 1, 8, 15, and 22; L-asparaginase (2500 U/m2) on days 1 through 14; and prednisone (60 mg/m2) on days 1 through 28. A total of 25 patients in the G-CSF group and 26 patients in the control arm fulfilled the inclusion criteria of the study. G-CSF markedly ameliorated neutropenia because the median proportion of days with neutropenia less than 1,000/microL was 29% in the G-CSF group as compared with 84% in the control arm (P < .00005). The median time to reach absolute neutrophil counts (ANC) > or = 1,000/microL was 16 days in G-CSF patients and 26 days in controls (P < .001). More importantly, G-CSF significantly reduced the incidence of febrile neutropenia (12% v 42% in controls, P < .05) and documented infections (40% v 77%, P < .05). No significant differences were found with regard to requirements for red blood cell transfusions and platelet concentrates. A total of 24 of 25 (96%) patients in the G-CSF group and 20 of 25 (80%) evaluable control patients had complete remission after phase I of induction therapy. We conclude that G-CSF can be safely administered as an adjunct to induction therapy of ALL and is clinically beneficial by ameliorating neutropenia and reducing infectious complications.

Colocalization of gold-labeled LDL and fibrinogen on platelets: enhanced fibrinogen binding induced by LDL

Low-density lipoproteins (LDL) specifically bind to the human platelet integrin-alpha IIb and -beta 3 (Koller et al., J. Biol. Chem. 264: 12412-12418, 1989). We show by electron microscopy (EM) that gold (Au)-labeled LDL bind to sites randomly distributed on the surface of platelets in suspension. Within a few minutes, mobile ligand-receptor complexes are translocated from the surface to the open canalicular system (OCS), which finally centralizes as a broad belt. Binding and translocation of Au-LDL are independent of stimulation of platelets by ADP and are completely reversible. Au-fibrinogen shows a strikingly similar, though agonist-dependent, redistribution behavior. Platelets are markedly activated by LDL. This activation is initiated by the binding of LDL to the plasma membrane receptor, and receptor internalization is probably not required for the activation but may instead be one of its consequences. Coincubation with Au-LDL and Au-fibrinogen results in more pronounced activation. The amount of OCS-localized ligands is significantly increased, most likely reflecting enhanced receptor recycling. The two ligands show a tendency to segregate in separate clusters, indicating differences in their postbinding pathways.

Differential targeting of T- and N-cadherin in polarized epithelial cells

To test whether glycosyl phosphatidylinositol-linked T-cadherin is a component of cell junctions like classical cadherins, we have examined its distribution and targeting in polarized epithelial cells. In vivo, T-cadherin was detected on the apical cell surface of the chick intestinal epithelium. In cultures of transfected Madin-Darby canine kidney cells, T-cadherin was also expressed apically, whereas classical N-cadherin resided basolaterally. Both cadherins were directly targeted to their respective membrane domains. Mutant proteins were expressed in Madin-Darby canine kidney cells to identify the regions responsible for differential cadherin localization. NDeltacyt, an N-cadherin cytoplasmic domain deletion mutant, was stably distributed basolaterally. This mutant was transported to both the apical and basolateral membrane compartments, followed by preferential removal from the apical surface. T-NDeltacyt, a T-cadherin mutant with the N-cadherin cytoplasmic domain deletion, was localized basolaterally, whereas N-TGPI, a GPI-anchored N-cadherin mutant, resided at the apical domain. The T-cadherin carboxyl-terminal 76 amino acids contain the apical targeting signal and include the signal for GPI anchor attachment. Basolateral localization of N-cadherin is achieved through targeting signals in the cytoplasmic domain. Thus, GPI-linked T-cadherin is not a component of cell junctions, consistent with a function as a recognition rather than a cell adhesion molecule.

All-trans retinoic acid and short-time, high-dose cytarabine in two children with acute promyelocytic leukemia

We report on two girls, 3 and 13 years old, with acute promyelocytic leukemia (APL) who were successfully treated with all-trans retinoic acid (ATRA) 45 mg/m2/day. "Retinoic acid syndrome" was prevented with short-time treatment of high dose (4 x 1.5 g/m2) cytarabine. This regimen was well tolerated, although both children were critically ill. They achieved a complete remission confirmed by light microscopy, but reverse transcriptase polymerase chain reaction remained positive after ATRA, underlining the need of further chemotherapy.

Ifosfamide, mitoxantrone and etoposide (VIM) as salvage therapy of low toxicity in non-Hodgkin's lymphoma

Patients with non-Hodgkin's lymphoma (NHL) who fail to respond to first-line treatment or relapse after having shown complete or partial remission have a poor prognosis, especially in high-grade NHL. Several salvage regimens show considerable toxicity and a poor long-term outcome. In this retrospective study we analyzed data of 55 patients (34 men and 21 women) with a median age of 66 years (range: 18-89). The combination chemotherapy (VIM) consisted of VP-16 (etoposide) 65 mg/m2, ifosfamide 650 mg/m2 and mitoxantrone 3 mg/m2 and was administered on 3 consecutive days along with mesna as uroprotection. Patients were treated for refractory disease or relapse and did not qualify for high-dose chemotherapy and ABMT. Stages according to the An Arbor classification were: stage I/16, II/4, III/8 and IV/37 patients. Thirty-three patients suffered from high-grade and 22 from low-grade NHL. Toxicity (WHO recommendations) was very mild. High-grade NHL showed a better response rate (18/33, 46%) than low-grade NHL (7/22, 36%). Overall response was 41% (12 CR and 11 PR) with a median duration of 36 months (range: 6-57 months). The combination therapy investigated exhibits mild toxicity even in extensively pretreated or elderly patients. The overall response rate of 41% might be improved by increased dosage and growth factor support.

FMS hemizygosity in myeloid dysplasia and acute myeloid leukemia with chromosomal aberration del(5)(q) demonstrated by polymerase chain reaction

Interstitial deletions of the long arm of chromosome 5 del(5)(q), are recurring aberrations in the myelodysplastic syndrome and acute myeloid leukemia. Several genes located in region (5)(q23-34) have been implicated as being of pathogenic importance. In this study seven samples of six patients with myelodysplastic syndrome and acute myeloid leukemia who have the del(5)(q) aberration were analyzed by polymerase chain reaction (PCR) and Southern blot technique. FMS hemizygosity was demonstrated in all patients. PCR analysis from peripheral blood samples confirmed the observations of this aberration found by semiquantitative Southern blot. PCR-based analysis can be used for primary diagnosis in addition to cytogenetic evaluation and for follow-up in patients with del(5)(q) aberration.

Analysis of peripheral blood progenitor cells demonstrates limitations of minimal residual disease diagnosis in a case of acute promyelocytic leukemia

Detection of minimal residual disease (MRD) by analysis of the PML-RAR alpha fusion transcript using the RT-PCR method is routinely carried out on peripheral blood and bone marrow of patients with APL (AML, FAB:M3). Therapy aims to achieve repeated negative results in these patients thus confirming clinical complete remission. We report a case of APL in second complete remission in which no leukemic cells had been detected in BM and PB for 20 months, and in which PBPC-pheresis was carried out for future transplantation. In two of five pheresis PML-RAR alpha fusion transcripts were detected. This shows that the residual leukemic population may only reach detection level after enrichment by PBPC-pheresis.

Early detection of minimal residual disease by reverse transcriptase polymerase chain reaction predicts relapse in acute promyelocytic leukemia

The PML/RAR alpha fusion RNA can be detected in acute promyelocytic leukemia (APL), cytogenetically characterized by the translocation t(15;17). Our study included ten newly diagnosed patients with APL who were investigated during the course of their diseases using reverse transcription polymerase chain reaction (RT-PCR). At diagnosis, aberrant fragments with a size heterogeneity due to alternative spliced products were detected in all patients, we observed breakpoints within bcr3 (short type) in two patients and bcr1 and 2 breakpoints (long type) in eight patients. Treatment consisted of all-trans retinoic acid (ATRA) in all patients; six patients received simultaneous cytostatic therapy during remission induction. At the time of complete hematological remission (CR), only two patients showed a negative RT-PCR result; eight of the ten patients were still PCR positive when nested primers were used. Subsequently, eight patients received consolidation chemotherapy and became PCR negative. Seven of eight patients are in continuous complete remission (median remission duration: 21 months, range: 11+ -26+ months). One patient of the chemotherapy group became PCR positive after 4 months in complete remission and relapsed after 6 months. The remaining two patients who were treated only with ATRA relapsed, received induction chemotherapy, and are in second and third complete remission, respectively. In conclusion. PCR negativity can be achieved only by chemotherapeutic consolidation; patients treated with ATRA alone remain PCR positive. Relapse is always preceded by a positive PCR result. Surprisingly, also patients without measurable PML/RAR alpha-mRNA in sequential analyses after cytostatic treatment became PCR positive and experienced relapse.

Characterization of LDL and VLDL binding sites on human basophils and mast cells

Recent data suggest that basophils and mast cells play a potential role in the processing and accumulation of plasma lipoproteins. This study investigated the interactions of 111In-low-density lipoprotein (LDL), 111In-acetyl-LDL, and 111In-very-low-density lipoprotein (VLDL) with purified primary human blood basophils, immortalized human basophils (KU812 cell line), and a human mast cell line, HMC-1. Binding sites for 111In-LDL resolved into curvilinear Scatchard plots indicating two classes of specific binding sites on primary basophils (Bmax1, 7404 sites/cell; Kd1, 1.9 nmol/L; Bmax2, 39,611 sites/cell; Kd2, 29 nmol/L), on KU812 cells (Bmax1, 8290 +/- 2690 sites/cell; Kd1, 2.4 +/- 0.6 nmol/L; Bmax2, 46,470 sites/cell; Kd2, 33.4 +/- 7.8 nmol/L), and on HMC-1 cells (Bmax1, 7840 +/- 360 sites/cell; Kd1, 1.8 +/- 0.8 nmol/L; Bmax2, 61,450 +/- 9900 sites/cell; Kd2, 28.4 +/- 9.4 nmol/L). On KU812 cells, binding of 111In-LDL was displaced by apolipoprotein (apo)-E-rich high-density lipoprotein (HDL) (IC50, 14 +/- 6 nmol/L), LDL (IC50, 29 +/- 11 nmol/L), VLDL (IC50, 55 +/- 21 nmol/L), HDL2 (IC50, 420 +/- 140 nmol/L), and heparin (IC50, 67 +/- 28 nmol/L), whereas no competition was produced by HDL, HDL3, or acetyl-LDL (IC50, > 1 mumol/L). Western blot analysis using the monoclonal antibody C7 confirmed the presence of the LDL receptor on human basophils and HMC-1 cells. 111In-acetyl-LDL binding sites (scavenger receptor) could be detected neither on human basophils nor on HMC-1 cells. 111In-VLDL bound to a single class of high-affinity binding sites on primary basophils (Bmax, 4320 sites/cell; Kd, 10 nmol/L), KU812 cells (Bmax, 4020 +/- 840 sites/cell; Kd, 8 +/- 3 nmol/L), and HMC-1 cells (Bmax, 6143 +/- 1866 sites/cell; Kd, 4 +/- 2 nmol/L). 111In-VLDL binding was displaced by VLDL > LDL > apoE-rich HDL but not by heparin (IC50 > 1 mmol/L). In the presence of prostaglandin E1, the number of 111In-LDL receptors increased by 150% (P < .05) in the high-affinity range and by 170% (P < .01) in the low-affinity range, whereas the number of 111In-VLDL binding sites remained unchanged. VLDL, LDL, HDL, and the subclasses HDL2 and HDL3 inhibited immunological histamine release by primary normal basophils (n = 3) and mast cells (n = 3). Our results provide evidence for the existence of LDL and VLDL binding sites on human basophils and HMC-1 mast cells. The exact biological and pathophysiological roles of these sites remain to be elucidated.

Absence of insulin receptor gene mutations in three insulin-resistant women with the polycystic ovary syndrome

Women with polycystic ovary syndrome (PCOS) are markedly insulin-resistant, but the molecular mechanisms of these changes and their relationship to the hyperandrogenic state remain to be clarified. Mutations have recently been identified in the insulin receptor gene of patients with extreme forms of insulin resistance associated with hyperandrogenism (eg, type A insulin resistance), and these mutations account for the insulin resistance in such patients. We performed this study to determine whether mutations in the coding portion of the insulin receptor gene were responsible for insulin resistance in PCOS. Insulin binding studies using cultured skin fibroblasts of three obese (body mass index > 27 kg/m2) women with PCOS (ie, mild hyperandrogenemia and chronic anovulation of unknown etiology) and documented insulin resistance showed no apparent abnormalities in either the number or affinity of insulin binding sites. Direct sequencing of all 22 exons of the insulin receptor gene from two of the women with PCOS did not reveal any mutations. Furthermore, both alleles of the gene were expressed at equal levels. In a third insulin-resistant PCOS woman, there was no evidence for a mutation in the coding portion of the insulin receptor gene as determined by denaturing gradient gel electrophoresis (DGGE). We conclude that the insulin resistance in these PCOS women was caused by a defect extrinsic to the insulin receptor.