Tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed-dose combination in moderate-to-severe acute pain: sustained analgesic effect over a 56-h period in the postoperative setting.

Multimodal analgesia constitutes a common strategy in pain management. A tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed combination (TRAM/DKP 75 mg/25 mg) has been recently registered and released in Europe for the treatment of moderate-to-severe acute pain. This paper provides additional analyses on the results of two phase III clinical trials (DEX-TRA-04 and DEX-TRA-05) on postoperative pain to document its sustained effect. The analysis was applied to a modified intention-to-treat population (mITT, n = 933) of patients undergoing active treatment from the first dose, to assess the sustained effect of TRAM/DKP 75 mg/25 mg on pain intensity (PI-VAS 0-100) over 56 h from first drug intake. The superior analgesic effect of TRAM/DKP 75 mg/25 mg over 56 h in terms of difference in PI-VAS (mean [SE]) was shown for DEX-TRA-04 (-11.0 [0.55] over dexketoprofen 25 mg and -9.1 [0.55] over tramadol 100 mg, P ≤ 0.0001) and for DEX-TRA-05 (-10.4 [0.51] over dexketoprofen 25 mg and -8.3 [0.51] over tramadol 100 mg, P ≤ 0.0001). The statistical analysis performed on data coming from both studies confirms the superior sustained analgesia of TRAM/DKP 75 mg/25 mg over tramadol 100 mg and dexketoprofen 25 mg. These results are consistent with the previously published data obtained on the ITT population and strongly support the role of this oral fixed-dose combination in the treatment of moderate-to-severe acute pain.

AMG 151 (ARRY-403), a novel glucokinase activator, decreases fasting and postprandial glycaemia in patients with type 2 diabetes.

Phase I studies have shown that AMG 151 activates glucokinase, a key enzyme in glucose homeostasis. The present randomized, placebo-controlled phase IIa study evaluated the dose-effect relationship of the glucokinase activator AMG 151 relative to placebo on fasting plasma glucose (FPG) in 236 patients (33-35 patients per arm) with type 2 diabetes treated with metformin. Patients received oral AMG 151 at 50, 100 or 200 mg twice daily, AMG 151 at 100, 200 or 400 mg once daily or matching placebo for 28 days. A significant linear dose-effect trend was observed with the twice-daily regimen (p = 0.004) for change in FPG to day 28. No trend was observed with the once-daily regimen. A higher incidence of hypoglycaemia and hypertriglyceridaemia was observed with AMG 151 administration. AMG 151 significantly reduced FPG when administered twice daily but not when administered once daily in patients with type 2 diabetes treated with metformin.

Diagnosis of infection after total hip replacement.

Subclinical infection in patients with pain following total hip replacement (THR) is an underestimated condition that needs consideration because it mimics aseptic loosening, contributes to periprosthetic osteolysis, and necessitates proper treatment. We aimed to define the reliability of diagnostic parameters that are routinely used before revision surgery for the assessment of infection. A continuous series of 26 subjects who underwent THR revision surgery was considered, including 21 cases diagnosed as aseptic loosening (group A) and 5 hip revisions with a clinical diagnosis for infection (group B). Seven subjects at the time of the primary arthroplasty were used as negative controls (group C). Technetium-99m labeled hydroxymethylene diphosphonate [(99m)Tc-HDP]- and technetium-99m hexamethylpropyleneamine oxide [(99m)Tc-HMPAO)]-labeled granulocyte scintigraphy, histology of peri-implant tissues, laboratory tests for inflammation, and microbiology were performed. Scintigraphy was positive for loosening [positive (99m)Tc-HDP scan] but negative for infection [negative (99m)Tc-HMPAO-labeled granulocyte scan] in all group A patients, whereas in 11 cases (52%) a positive culture was unexpectedly obtained. Histology showed conflicting results: Polymorphonuclear cells (PMNs) were found only in 5 of 11 culture-positive patients, whereas in 2 cases the presence of PMNs did not correspond to a positive culture. In group B patients, both isotope scans and microbiology were found to be positive. All control subjects (group C) had negative cultures. In our opinion, smoldering infection could be present in a significant proportion of cases of failed hip implants currently diagnosed as "nonseptic." The inflammatory response to wear debris and the presence of superimposed, slowly growing bacteria could act synergically, both contributing to the pathogenesis of periprosthetic osteolysis.

The influence of alumina and ultra-high molecular weight polyethylene particles on osteoblast-osteoclast cooperation.

Particle-induced macrophage activation, mainly by UHMWPE wear, has been recognized as the biological mechanism leading to periprosthetic bone resorption, which is responsible for the loosening of the total hip replacements (THR). Ceramic-on-ceramic implants have been advocated as a means of reducing wear products. Many studies investigated the effect of alumina (Al(2)O(3)) particles on monocytes/macrophages, but only limited information are available on their participation to bone turnover. An in vitro model was performed to investigate how Al(2)O(3) and UHMWPE particles may influence the osteoblast-osteoclast interaction: human osteoblasts (HOB) were obtained from trabecular bone, while osteoclasts were derived from peripheral blood mononuclear cells (PBMC) of healthy donors. The amount of IL6, TNF alpha, GM-CSF, and other factors acting on the bone turnover, i.e. the 'receptor activator of NF kappa B' ligand (RANKL) and osteoprotegerin (OPG), was detected in culture medium of particle-challenged HOB (HOB-CM). The Al(2)O(3) and UHMWPE particles did not affect either cell viability or TNF and GM-CSF release, while the increase in IL6 release seemed to be dependent on the particle concentration. UHMWPE increased the release of RANKL from HOB, while OPG and OPG-to-RANKL ratio were significantly inhibited. The ability of HOB-CM to promote osteoclastogenesis was tested via osteoblast/monocyte cooperation: after seven days of culture UHMWPE HOB-CM induced a large amount of multinucleated TRAP-positive giant cells, as well as significantly reduced the amount of IL6, GM-CSF and RANKL in the supernatant. With regard to the inductive effect on the osteoclastogenesis, our results show that the Al(2)O(3) wear debris are less active.

Osteoid osteoma simulating an osteocartilaginous exostosis.

We describe a case of osteoid osteoma in the tibia of a 3-year-old patient who presented with a clinical and radiographic picture that suggested an exostosis. The formation of osteoid osteoma with a radiographic picture similar to that of osteophytes or exostosis has been previously documented only rarely. The authors hypothesize that the exostosis-like formation observed was actually the calcification of soft tissues that formed after the intense periosteal inflammatory reaction caused by the osteoid osteoma. As a result of its peculiar clinical and radiographic presentation, diagnosis of this lesion was delayed. Being located close to the medial growth plate of the tibia, it caused lengthening of the limb with a pronounced valgus deviation of the knee. An excisional biopsy provided histological evidence, clinical resolution and immediate pain relief, but incomplete resolution of the valgus deformity of the knee.

Deep peroneal nerve paresis in a runner caused by ganglion at capitulum peronei. Case report and review of the literature.

Although lateral popliteal sciatic nerve damage is not one of the commonest diseases in the general population, it is quite frequent among athletes. Several physiopathologic mechanisms have been thought to bring about this damage in athletes. Soft tissue ganglions with neurological involvement of the lateral popliteal sciatic nerve or its terminal rami are in differential diagnosis with several lesions of this area, as direct or indirect trauma, subcutaneous rupture of anterior tibialis muscle and long peroneal muscle, disc hernia, intraspinal tumor, anterior tarsal tunnel syndrome, cysts, neurofibroma, baker's cyst, vascular claudication, stenosing or inflammatory pathology of 2(nd) motoneuron, antimicrobial agents for urinary tract infection (nitrofurnantoin). The authors report the case of a 34-year-old amateur athlete with a recent paralysis of the hallux extensor, paresis of the toe extensor and hyposthenia of the tibialis anterior. The patient had been suffering from episodes of lumbalgia for a long time. He was sent to us because neurological damage due to disc herniation was suspected. Electromyography, sonography, and CT showed peripheral compression of the deep peroneal nerve caused by a mucous cyst at the capitulum peronei, a ''rare'' condition. The patient underwent surgery to excise the cyst, which led to the rapid resolution of the nerve deficit shown by clinical and electromyographical tests. A meticulous anamnesis and accurate objective examination, followed by specific tests (radiographs, sonography, and possibly CT scan) generally enable a correct diagnosis to be made. If diagnosis and therapy are carried out correctly, and without delay, symptoms quickly resolve and the nerve deficit progressively regresses.

Role of macrophage-expressed adipocyte fatty acid binding protein in the development of accelerated atherosclerosis in hypercholesterolemic mice.

Atherosclerosis is an inflammatory disease process associated with elevated levels of plasma cholesterol, especially low-density lipoproteins. The latter become trapped within the arterial wall and are oxidized and taken up by macrophages to form foam cells. This process is an initiating event for atherosclerosis. Fatty acid binding proteins (FABP) are involved in fatty acid metabolism and cellular lipid transport, and adipocyte FABP (aP2) is also expressed in macrophages. We recently generated mice lacking both apolipoprotein (Apo)E and aP2 (ApoE-/-aP2-/-) and found that these mice, compared with ApoE-/- mice, developed markedly smaller atherosclerotic lesions that contained fewer macrophages. Here we investigated the mechanism(s) responsible for this prevention of atherosclerotic lesion formation. Bone marrow transplantations were performed in ApoE-/- mice, receiving cells from either ApoE-/- or ApoE-/-aP2-/- mice. The lack of aP2 in donor marrow cells led to the development of smaller (5.5-fold) atherosclerotic lesions in the recipient mice. No differences were found in plasma cholesterol, glucose, or insulin levels between recipients of bone marrow cells from ApoE-/- or ApoE-/-aP2-/- mice. However, the expression of chemoattractant and inflammatory cytokines was decreased in macrophages from ApoE-/-aP2-/- mice compared with ApoE-/- mice, which may contribute to the decrease in atherosclerotic lesion formation. Taken together, we demonstrate the importance of macrophage aP2 in the development of atherosclerotic lesions.

Exacerbation of chronic renovascular hypertension and acute renal failure in heme oxygenase-1-deficient mice.

Heme oxygenase (HO) is a cytoprotective enzyme that degrades heme (a potent oxidant) to generate carbon monoxide (a vasodilatory gas that has anti-inflammatory properties), bilirubin (an antioxidant derived from biliverdin), and iron (sequestered by ferritin). Because of properties of HO and its products, we hypothesized that HO would be important for the regulation of blood pressure and ischemic injury. We studied chronic renovascular hypertension in mice deficient in the inducible isoform of HO (HO-1) using a one kidney-one clip (1K1C) model of disease. Systolic blood pressure was not different between wild-type (HO-1(+/+)), heterozygous (HO-1(+/-)), and homozygous null (HO-1(-/-)) mice at baseline. After 1K1C surgery, HO-1(+/+) mice developed hypertension (140+/-2 mm Hg) and cardiac hypertrophy (cardiac weight index of 5.0+/-0.2 mg/g) compared with sham-operated HO-1(+/+) mice (108+/-5 mm Hg and 4.1+/-0.1 mg/g, respectively). However, 1K1C produced more severe hypertension (164+/-2 mm Hg) and cardiac hypertrophy (6.9+/-0.6 mg/g) in HO-1(-/-) mice. HO-1(-/-) mice also experienced a high rate of death (56%) within 72 hours after 1K1C surgery compared with HO-1(+/+) (25%) and HO-1(+/-) (28%) mice. Assessment of renal function showed a significantly higher plasma creatinine in HO-1(-/-) mice compared with HO-1(+/-) mice. Histological analysis of kidneys from 1K1C HO-1(-/-) mice revealed extensive ischemic injury at the corticomedullary junction, whereas kidneys from sham HO-1(-/-) and 1K1C HO-1(+/-) mice appeared normal. Taken together, these data suggest that chronic deficiency of HO-1 does not alter basal blood pressure; however, in the 1K1C model an absence of HO-1 leads to more severe renovascular hypertension and cardiac hypertrophy. Moreover, renal artery clipping leads to an acute increase in ischemic damage and death in the absence of HO-1.

ESE-1 is a novel transcriptional mediator of inflammation that interacts with NF-kappa B to regulate the inducible nitric-oxide synthase gene.

Inflammation is a hallmark of several vascular diseases. The nuclear factor kappaB (NF-kappaB) transcription factors are dimeric proteins involved in the activation of a large number of genes in response to inflammatory stimuli. We report the involvement of a novel member of the ETS transcription factor, ESE-1, in mediating vascular inflammation. ESE-1 is induced in response to inflammatory cytokines and lipopolysaccharide in vascular smooth muscle cells, endothelial cells, and cells of the monocyte-macrophage lineage. This induction occurs within hours of stimulation and is mediated by NF-kappaB transactivation of the ESE-1 promoter. We have identified the inducible form of nitric-oxide synthase (NOS2) as a putative target for ESE-1. ESE-1 can bind to the p50 subunit of NF-kappaB, and cotransfection of ESE-1 with the p50 and p65 subunits of NF-kappaB synergistically enhances transactivation of the NOS2 promoter by ESE-1. An ESE-1-binding site within the NOS2 promoter has been identified, the site-directed mutagenesis of which completely abolishes the ability of ESE-1 to transactivate the NOS2 promoter. Finally, in a mouse model of endotoxemia, associated with acute vascular inflammation, ESE-1 is strongly expressed in vascular endothelium and smooth muscle cells. In summary, ESE-1 represents a novel mediator of vascular inflammation.

Down-regulation of high mobility group-I(Y) protein contributes to the inhibition of nitric-oxide synthase 2 by transforming growth factor-beta1.

The inducible isoform of nitric-oxide synthase (NOS2) catalyzes the production of nitric oxide (NO), which participates in the pathophysiology of systemic inflammatory diseases such as sepsis. NOS2 is transcriptionally up-regulated by endotoxin and inflammatory cytokines, and down-regulated by transforming growth factor (TGF)-beta1. Recently we have shown that high mobility group (HMG)-I(Y) protein, an architectural transcription factor, contributes to NOS2 gene transactivation by inflammatory mediators. The aim of the present study was to determine whether regulation of HMG-I(Y) by TGF-beta1 contributes to the TGF-beta1-mediated suppression of NOS2. By Northern blot analysis, we show that TGF-beta1 decreased cytokine-induced HMG-I(Y) mRNA levels in vascular smooth muscle cells and macrophages in vitro and in vivo. Western analysis confirmed the down-regulation of HMG-I(Y) protein by TGF-beta1. To determine whether the down-regulation of HMG-I(Y) contributed to a decrease in NOS2 gene transactivation by TGF-beta1, we performed cotransfection experiments. Overexpression of HMG-I(Y) was able to restore cytokine inducibility of the NOS2 promoter that was suppressed by TGF-beta1. The effect of TGF-beta1 on NOS2 gene transactivation was not related to a decrease in binding of HMG-I(Y) to the promoter of the NOS2 gene, but due to a decrease in endogenous HMG-I(Y) protein. These data provide the first evidence that cytokine-induced HMG-I(Y) can be down-regulated by TGF-beta1. This down-regulation of HMG-I(Y) contributes to the TGF-beta1-mediated decrease in NOS2 gene transactivation by proinflammatory stimuli.

Transforming growth factor-beta 1 inhibition of macrophage activation is mediated via Smad3.

Activated macrophages are critical cellular participants in inflammatory disease states. Transforming growth factor (TGF)-beta1 is a growth factor with pleiotropic effects including inhibition of immune cell activation. Although the pathway of gene activation by TGF-beta1 via Smad proteins has recently been elucidated, suppression of gene expression by TGF-beta1 remains poorly understood. We found that of Smad1-Smad7, Smad3 alone was able to inhibit expression of markers of macrophage activation (inducible nitric-oxide synthase and matrix metalloproteinase-12) following lipopolysaccharide treatment in gene reporter assays. Transient and constitutive overexpression of a dominant negative Smad3 opposed the inhibitory effect of TGF-beta1. Domain swapping experiments suggest that both the Smad MH-1 and MH-2 domains are required for inhibition. Mutation of a critical amino acid residue required for DNA binding in the MH-1 of Smad3 (R74A) resulted in the loss of inhibition. Transient overexpression of p300, an interactor of the Smad MH-2 domain, partially alleviated the inhibition by TGF-beta1/Smad3, suggesting that inhibition of gene expression may be due to increased competition for limiting amounts of this coactivator. Our results have implications for the understanding of gene suppression by TGF-beta1 and for the regulation of activated macrophages by TGF-beta1.

Thioredoxin facilitates the induction of heme oxygenase-1 in response to inflammatory mediators.

Heme oxygenase (HO)-1 is a stress response protein that is regulated by oxidative stress. HO-1 catalyzes the generation of biliverdin, carbon monoxide, and iron from heme. Lipopolysaccharide (LPS) and interleukin (IL)-1beta induce HO-1 through the binding of nuclear proteins to AP-1 motifs in enhancer regions upstream from the transcription start site. The DNA binding activity of AP-1 proteins depends on the reduction of cysteines in their DNA-binding domains. We found that agents that disrupt free sulfhydryl groups abolish AP-1 binding activity in nuclear proteins obtained from rat aortic smooth muscle cells and macrophages stimulated with IL-1beta or LPS. Thioredoxin (TRX) may regulate the redox status of nuclear transcription factors in response to oxidative stimuli, thus we determined the role of TRX in the physiologic regulation of HO-1. TRX underwent nuclear translocation in cells stimulated with IL-1beta and LPS. We transfected macrophages with a heterologous promoter construct containing two AP-1 sites from an upstream enhancer region in the HO-1 promoter. Recombinant TRX induced promoter activity to a level analogous to that induced by LPS, and this TRX response was abolished by mutation of the AP-1 sites. An inhibitor of TRX reductase, used to prevent TRX translocation in the reduced state, decreased HO-1 induction by IL-1beta and LPS. These data provide the first evidence that TRX contributes to the induction of HO-1 by inflammatory mediators.

Role of activating protein-1 and high mobility group-I(Y) protein in the induction of CD44 gene expression by interleukin-1beta in vascular smooth muscle cells.

CD44 is a multifunctional cell adhesion molecule that participates in pathological states such as inflammation and tumorigenesis. CD44 is induced on vascular smooth muscle cells after arterial wall injury and may mediate their proliferation and migration into the neointima during arteriosclerosis. We have demonstrated elsewhere that the proinflammatory cytokine interleukin (IL)-1beta up-regulates CD44 mRNA and protein expression in cultured rat aortic smooth muscle cells (RASMC) by increasing gene transcription. By transient transfection of 5'-deletion constructs into RASMC, we show in the present study that a conserved AP-1 site 110 base pairs from the transcription start site of the mouse CD44 promoter is important for basal activity. Mutation of the AP-1 site significantly reduced induction of promoter activity by IL-1beta, and electrophoretic mobility shift assays demonstrated that Fos and c-Jun were present in the CD44 AP-1 binding complex after IL-1beta stimulation. In addition, cotransfection of the architectural transcription factor high mobility group (HMG)-I(Y) protein with c-Fos and c-Jun markedly increased trans-activation of the CD44 promoter. Taken together, our studies demonstrate that AP-1 proteins are a central regulatory component used by IL-1beta to modulate expression of CD44 during an inflammatory response in vascular smooth muscle cells and that transcription of CD44 by AP-1 proteins is enhanced by HMG-I(Y). -Foster, L. C., Wiesel, P., Huggins, G. S, Pañares, R., Chin, M. T., Pellacani, A., Perrella, M. A. Role of activating protein-1 and high mobility group-I(Y) protein in the induction of CD44 gene expression by interleukin-1beta in vascular smooth muscle cells.

Endotoxin-induced mortality is related to increased oxidative stress and end-organ dysfunction, not refractory hypotension, in heme oxygenase-1-deficient mice.

BACKGROUND: Heme oxygenase (HO)-1 is an enzyme that degrades heme to generate CO (a vasodilatory gas), iron, and the potent antioxidant bilirubin. A disease process characterized by decreases in vascular tone and increases in oxidative stress is endotoxic shock. Moreover, HO-1 is markedly induced in multiple organs after the administration of endotoxin (lipopolysaccharide [LPS]) to mice. METHODS AND RESULTS: To determine the role of HO-1 in endotoxemia, we administered LPS to mice that were wild-type (+/+), heterozygous (+/-), or homozygous null (-/-) for targeted disruption of HO-1. LPS produced a similar induction of HO-1 mRNA and protein in HO-1(+/+) and HO-1(+/-) mice, whereas HO-1(-/-) mice showed no HO-1 expression. Four hours after LPS, systolic blood pressure (SBP) decreased in all the groups. However, SBP was significantly higher in HO-1(-/-) mice (121+/-5 mm Hg) after 24 hours, compared with HO-1(+/+) (96+/-7 mm Hg) and HO-1(+/-) (89+/-13 mm Hg) mice. A sustained increase in endothelin-1 contributed to this SBP response. Even though SBP was higher, mortality was increased in HO-1(-/-) mice, and they exhibited hepatic and renal dysfunction that was not present in HO-1(+/+) and HO-1(+/-) mice. The end-organ damage and death in HO-1(-/-) mice was related to increased oxidative stress. CONCLUSIONS: These data suggest that the increased mortality during endotoxemia in HO-1(-/-) mice is related to increased oxidative stress and end-organ (renal and hepatic) damage, not to refractory hypotension.

Acute methylprednisolone administration induces a transient alteration of glucose tolerance and pyruvate dehydrogenase in humans.

BACKGROUND: Glucocorticoid administration induces alteration of glucose tolerance, and impairment of glucose oxidation may contribute to glucocorticoid-induced derangement of glucose metabolism. We investigated glucose tolerance following methylprednisolone administration in humans. In the same model, we evaluated pyruvate dehydrogenase (PDH), the rate limiting enzyme of glucose oxidation, in peripheral blood mononuclear cells. MATERIALS AND METHODS: Methylprednisolone (2 x 40 mg, iv, one dose every 12 h) was administered to six healthy volunteers. Glucose tolerance was evaluated through an oral glucose tolerance test (oGTT, 75 g glucose) at least a week before and after drug administration (2 and 24 h post-drug). To assess modifications of lipid metabolism circulating free fatty acids (FFA) and glycerol were measured, during fasting and oGTT. The active form of PDH (PDHa) was evaluated in peripheral blood mononuclear cells, both as ex vivo activity and as in vitro response to insulin (30 pmol l-1). RESULTS: Methylprednisolone induced an alteration of glucose tolerance 2 h after its administration. Such alteration was completely reversed at 24 h. Alteration of glucose tolerance was accompanied by decreased ex vivo PDHa activity. PDH responsiveness to insulin in vitro was also impaired. Circulating FFA were unmodified, but decreased glycerol levels suggested a slight inhibition of lipolysis. CONCLUSIONS: Acute methylprednisolone administration in humans induced a transient decrease of glucose tolerance 2 h after drug administration, accompanied by hyperinsulinaemia, inhibition of ex vivo PDH activity and its response to insulin in vitro. These alterations were completely abolished at 24 h, suggesting that methylprednisolone can be safely administered acutely. Furthermore, methylprednisolone induced only minor modifications of circulating FFA and glycerol, indicating minimal impact on lipid metabolism.

In vitro study of the combination gemcitabine + fludarabine on freshly isolated chronic lymphocytic leukemia cells.

BACKGROUND AND OBJECTIVE: Fludarabine has shown a definite clinical activity in B-cell chronic lymphocytic leukemia (CLL). If the effects of this drug could be potentiated, it could be useful in order to obtain complete remissions. In this study we evaluated the effects of the combination of fludarabine and gemcitabine, a deoxycytidine analog that has shown both in vitro and in vivo activity against a variety of solid tumors. DESIGN AND METHODS: CLL cells from 10 patients were cultured in vitro in the presence of fludarabine (0.5-1,000 microg/mL) and gemcitabine (0.1-5,000 microg/mL), both alone and in different combinations. Cytotoxic activity was tested by the XTT colorimetric assay. Furthermore we evaluated BCL-2 protein expression and, subsequently, the induction of apoptosis at baseline and after exposing cells to different concentrations of fludarabine and gemcitabine. RESULTS: The IC(50) of fludarabine and gemcitabine on CLL cells was 550 and 1,100 microg/mL, respectively, in our series of samples; the cytotoxicity of either drug was not influenced by the percentage of BCL-2 positive cells in the same sample. The addition of gemcitabine increased fludarabine-induced cytotoxicity; however, isobologram analysis of the data showed synergism only when lower doses of gemcitabine were combined to fludarabine. Induction of apoptosis reflected this pattern of activity. INTERPRETATION AND CONCLUSIONS: Gemcitabine was able to increase the activity of fludarabine only when low doses of the former were employed. As both compounds incorporate into DNA blocking chain elongation, our results could be explained by the drugs interfering at that level. The possibility of potentiating the effects of fludarabine with low doses of gemcitabine renders this combination promising in view of an in vivo use.

All-trans retinoic acid at low concentration directly stimulates normal adult megakaryocytopoiesis in the presence of thrombopoietin or combined cytokines.

In order to investigate the direct effects of retinoids on normal adult hematopoietic progenitors, purified CD34+ cells were seeded in serum-free cultures in the presence of pharmacological (10(-6)) M or physiological (10(-12)) M concentrations of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9-cis RA) plus combinations of specific cytokines. 10(-6) M ATRA and 9-cis RA significantly decreased the number of granulomacrophagic, erythroid and megakaryocytic (CFU-meg) progenitors. On the other hand, 10(-12) M ATRA significantly promoted the growth of CFU-meg, in the presence either of thrombopoietin or of IL-3+ GM-CSF, and induced a reproducible stimulation of the immature CD34+DR- subset. In conclusion, our findings suggest that retinoic acids probably play a direct role in normal adult hematopoietic development at both physiological and pharmacological concentrations. The stimulatory effect on megakaryocytopoiesis should be considered in the perspective of a potential use of low-dose ATRA, combined with thrombopoietin or other cytokines, in pathological conditions where the megakaryocytic compartment is impaired and the stimulation of megakaryocytopoiesis is requested.

Cytotoxic combination of loxoribine with fludarabine and mafosfamide on freshly isolated B-chronic lymphocytic leukemia cells.

Fludarabine has shown a definite clinical activity in B-cell chronic lymphocytic leukemia (B-CLL). Recently it has been demonstrated that loxoribine, a guanine ribonucleotide derivative, is able to increase the cytotoxicity of fludarabine in B-CLL cells, in vitro. We have here extended these findings by testing the activity of loxoribine in combination with fludarabine and mafosfamide. As we have previously demonstrated, loxoribine enhances the activity of fludarabine at all concentrations, while only lower doses of mafosfamide seem to be positively affected by loxoribine. The combination of fludarabine and mafosfamide is synergistic on CLL cells, and the cytotoxic activity is increased by the addition of loxoribine. We have also evaluated the pro-apoptotic activity of each drug, both alone and in combination; these results are concordant with the cytotoxicity data, thus demonstrating that, even though loxoribine is more active in combination with fludarabine than with mafosfamide, the efficacy of the triple combination is higher than that obtained with any other agent alone or in double combination.