Streptomycin and EDTA decrease the number of desmin-negative fibers following stretch injury

Streptomycin and ethylene diamine tetraacetic acid (EDTA) were used to examine the role of extracellular calcium in stretch-induced muscle injury. Streptomycin was injected in one group of rats, three times daily for 8 days (S, 300 mg.kg(-1).day(-1) intraperitoneally). In another group, EDTA was administered (150 mg.kg(-1) IP) 20 min before and 24 h after the injury protocol. Untreated rats (C) served as controls. Muscle injury was produced by 40 stretches of active dorsiflexor muscles by ankle rotation from 80 degrees to 130 degrees (velocity 1.75 rad.s(-1)). Ten minutes after the injury protocols, all animals lost the same amount of isometric force at both low and high stimulation frequencies (20 HZ; S, 56 +/- 6%; EDTA, 47 +/- 7%; C, 55 +/- 4%) and 120 HZ; S, 11 +/- 3%, EDTA, 13 +/- 3%; C, 11 +/- 3%). Tibialis anterior (TA) muscles were removed after 48 h for morphometric analysis. In both streptomycin-and EDTA-treated rats, the percent of injured (i.e., desmin-negative) myofibers in TA was reduced compared to untreated, injured muscles (S, 0.35 +/- 0.08%; EDTA, 0.64 +/- 0.19%; C, 1.81 +/- 0.43%). Thus, streptomycin and EDTA treatment did not alter the development of muscle weakness (i.e., isometric force deficit), but almost abolished the histopathologic changes. This study shows that the mechanisms for muscle weakness and histopathologic changes (inflammation) following repeated muscle strains can largely be dissociated from each other and helps explain why there is no correlation between isometric force deficits and the number of pathologic cells.

Down-regulation of amyloid precursor protein by peptide nucleic acid in vivo

Alzheimer's disease (AD) is a neurodegenerative disease associated with increased expression of amyloid precursor protein (APP) and the deposition of its proteolytic cleavage products, the amyloid-beta peptides, Abeta(1-40) and Abeta(1-42). Peptide nucleic acids (PNAs) have been shown to block the expression of proteins at transcriptional and translational levels. In this study we used a sense and an antisense PNA specifically targeted to APP to inhibit the transcription and translation of APP by complementary binding to DNA or mRNA, respectively. Using Western blotting, APP showed a drastic decrease (50% and 90% reduction, in two separate experiments, as compared with saline control) with the injection of sense APP. mRNA levels were higher at the same time point after injection of APP sense PNA, most probably because of a compensatory mechanism in response to the drop of APP that might have occurred at an earlier time point (0-1 h) and was reflected in a drop at the protein level at 1 h. The injection of antisense PNA showed about 70% decrease in APP as measured by Western blotting. Unmodified PNA can be used in vivo to reduce the levels of APP, which plays a critical role in the development of AD.

FDA-preapproved drugs targeted to the translational regulation and processing of the amyloid precursor protein

The 5' untranslated region (5'UTR) of the transcript encoding the Alzheimer's amyloid precursor protein (APP) is a key regulatory sequence that determines the amount of intracellular APP holoprotein present in brain derived cells. Using neuroblastoma cells (SY5Y) we developed a transfection based screen of a library of FDA drugs to identify compounds that limited APP luciferase reporter expression translated from the APP 5'UTR. Paroxetine (Paxil trade mark ), dimercaptopropanol, phenserine, desferrioxamine, tetrathiolmobdylate, and azithromycin were six leads that were subsequently found to also suppress APP holoprotein levels or to alter APP cleavage (azithromycin). Since APP holoprotein levels are proportionate to Abeta peptide output in many systems we tested the efficacy of paroxetine and dimercaptopropanol to limit Abeta secretion as measured by ELISA assays. Paroxetine and dimercaptopropanol limited Abeta peptide secretion from lens epithelial cells (B3 cells). Interestingly, paroxetine changed the steady-state levels of transferrin receptor mRNAs. These data suggested that this serotonin reuptake inhibitor (SSRI) provided extra pharmacological action to chelate interacellular iron or change the intracellular iron distribution. An altered iron distribution would be predicted to indirectly limit APP holoprotein expression and Abeta peptide secretion.

[Evaluation of Helicobacter pylori susceptibility to rifaximin]

INTRODUCTION

Helicobacter pylori infection affects more than half the world's population. It is a major cause of chronic gastritis and there is a strong association with peptic ulceration and gastric adenocarcinoma. Rifaximin is a new nonabsorbable broad-spectrum antimicrobial agent that reaches high concentrations in the gastrointestinal tract.

AIM

To evaluate the in vitro activity of rifaximin against H. pylori isolates.

METHODS

Thirty-one H. pylori strains were analyzed by the agar dilution method. Clarithromycin was used as the control antibiotic. Staphylococcus aureus and Streptococcus pneumoniae were used as quality control strains. Plates were read at days 4 and 7 of incubation. The MIC50 and MIC90 of each antibiotic were calculated. Strains with a clarithromycin MIC of > 1 microg/ml were considered resistant.

RESULTS

The MIC50 of clarithromycin at days 4 and 7 was 0.125 microg/ml and the MIC90 at days 4 and 7 ranged from 8 to 16 microg/ml, respectively. The MIC50 of rifaximin at days 4 and 7 ranged from 1 to 2 microg/ml, respectively, and the MIC90 was 4 microg/ml at both days 4 and 7. Twenty percent of H. pylori strains were resistant to clarithromycin. All clarithromycin-resistant strains were inhibited at a maximal rifaximin concentration of 4 microg/ml.

CONCLUSION

These results indicate that this new antibiotic may be useful for eradication of H. pylori infection. Because rifaximin is active against H. pylori strains resistant to clarithromycin, it could be useful in combination with this drug or in the treatment of therapeutic failure.

Linezolid

Linezolid is an oxazolidinone antibacterial agent that acts by inhibiting the initiation of bacterial protein synthesis. Linezolid has a wide spectrum of activity against gram-positive organisms including methicillin resistant staphylococci, penicillin resistant pneumococci and vancomycin resistant enterococcus faecalis and E. faecium. Linezolid has a good bio-availability orally and could be switched from parenteral to oral therapy while treating serious infections. Linezolid is well tolerated in children.

Ureteral replacement using small-intestinal submucosa and a collagen inhibitor in a porcine model

PURPOSE

Small-intestinal submucosa (SIS) has been successful as an onlay graft in ureteral repair, but tubularized segment interposition of SIS has been unsuccessful. Our objective was to evaluate whether a type I collagen inhibitor, halofuginone, would prevent stricture formation in tubularized SIS interposition.

MATERIALS AND METHODS

We performed either laparoscopic partial ureteral excision followed by an SIS onlay graft (N = 5) or complete laparoscopic ureteral excision followed by an SIS interposition graft (N = 7) in domestic pigs. Animals received either no (N = 3), low-dose (N = 5), or high-dose (N = 4) halofuginone. Animals had ureteral stenting for 2 weeks after surgery and were permitted to survive for 6 or 9 weeks. An intravenous urogram (IVU) was performed prior to sacrifice. Kidneys were examined grossly and histologically.

RESULTS

One animal that received an onlay graft died of an unrelated illness. The remaining four ureteral onlay animals, including one control and two low-dose and one high-dose pig, had grossly normal kidneys at harvest. The IVU was normal in the control and high-dose animal but showed delayed excretion with mild hydroureteronephrosis in the low-dose animals. Pathologic examination of the SIS site revealed circumferential reepithelialization with inflammation and mild fibrosis. All seven tubularized interposition graft kidneys demonstrated either severe hydroureteronephrosis (N = 5) or renal atrophy (N = 2), and all had complete obstruction on IVU. Pathologic examination revealed a stenotic ureteral lumen with extensive surrounding inflammation and fibrosis.

CONCLUSIONS

An SIS onlay graft was successful in the porcine model of ureteral injury. Halofuginone, a type I collagen inhibitor, did not demonstrate a significant beneficial effect in this technique. Ureteral tubularized interpositions with SIS are unsuccessful and not improved by halofuginone.

Aneurysmal subarachnoid hemorrhage in a patient with Wegener?s granulomatosis

A 34-year-old Japanese man admitted to hospital with pneumonia had previously undergone surgery for paranasal sinusitis and also for the clipping of an aneurysm at the origin of the anterior choroidal artery after subarachnoid hemorrhage. Laboratory tests performed at the present admission showed renal insufficiency and serological findings of raised proteinase 3 antineutrophil cytoplasmic antibody level. A renal biopsy was performed that showed diffuse necrotizing glomerulonephritis with fibrocellular crescents. The diagnosis of Wegener's granulomatosis(WG) was confirmed on the basis of the clinical picture, laboratory findings, and biopsies of renal tissues. The disease responded to prednisolone and cyclophosphamide. The association of WG with a ruptured intracranial aneurysm is rare and has not previously been confirmed.

The behavioral deficit observed following noncontingent shock in spinalized rats is prevented by the protein synthesis inhibitor cycloheximide

Spinalized rats that receive shock when 1 hind limb is extended (contingent shock) exhibit an increase in flexion duration, a simple form of instrumental learning. Rats that receive shock independent of leg position (noncontingent shock) do not exhibit an increase in flexion duration and fail to learn when tested with contingent shock 24 hr later. It appears that noncontingent shock induces an intraspinal modification that inhibits the capacity to learn. The authors propose that the mechanisms that underlie this effect depend on de novo protein synthesis. To evaluate this hypothesis, the authors gave spinalized rats the protein synthesis inhibitor Cycloheximide (CXM) or saline intrathecally prior to, or immediately after, noncontingent shock exposure. Twenty-four hours later, rats were tested with contingent shock. Rats that received the vehicle and noncontingent shock failed to learn. CXM-treated shocked rats learned normally, suggesting that the learning deficit depends on protein synthesis within the spinal cord.

Efficacy and tolerability of linezolid in treating severe skin and soft tissue infections caused by Gram-positive pathogens

BACKGROUND AND PURPOSE

Linezolid, an oxazolidinone, has shown efficacy in the treatment of adults with nosocomial or community-acquired pneumonia; skin and soft tissue infections; and infections due to methicillin-resistant Staphylococcus aureus. The purpose of this open-label, single-arm, multicenter study was to evaluate the efficacy and tolerability of linezolid in patients from the Asia-Pacific Region with severe Gram-positive skin and soft tissue infections.

METHODS

166 patients at 27 sites in 7 countries from the Asia-Pacific region were enrolled. The patients had severe skin infection involving the deeper layers or extensive surface area. Patients received 7 to 28 days of treatment with linezolid by clinical judgment. All patients received intravenous linezolid 600 mg twice a day initially and were switched over to an equivalent oral dose (600 mg twice a day) when the investigator discerned clinical improvement. The primary efficacy endpoint in this study was clinical outcome at the follow-up visit, 14 to 21 days after completion of treatment (test of cure), and the secondary efficacy variable was microbiologic response at test-of-cure.

RESULTS

166 patients received the study medication and were included in the intent-to-treat analysis. The clinical success rate was approximately 93% in both the intent-to-treat and clinically evaluable populations at the end of treatment and test-of-cure visits. In the modified intent-to-treat and microbiologically evaluable populations, the microbiologic success rates at the test-of-cure visit were 88.9% and 93.8%, respectively. The most frequent treatment-emergent adverse events were nausea (13%), dizziness (8%), anemia (7%), and vomiting (5%).

CONCLUSIONS

Linezolid was effective and well tolerated in patients with severe skin and soft tissue infections caused by Gram-positive pathogens.

Lincomycin, clindamycin and their applications

Lincomycin and clindamycin are lincosamide antibiotics used in clinical practice. Both antibiotics are bacteriostatic and inhibit protein synthesis in sensitive bacteria. They may even be bactericidal at the higher concentrations that can be reached in vivo. Clindamycin is usually more active than lincomycin in the treatment of bacterial infections, in particular those caused by anaerobic species; and it can also be used for the treatment of important protozoal diseases, e.g. malaria, most effectively in combination with primaquine. Resistance to lincomycin and clindamycin may be caused by methylation of 23S ribosomal RNA, modification of the antibiotics by specific enzymes or active efflux from the periplasmic space.

Amelioration of radiation-induced fibrosis: inhibition of transforming growth factor-beta signaling by halofuginone

Radiation-induced fibrosis is an untoward effect of high dose therapeutic and inadvertent exposure to ionizing radiation. Transforming growth factor-beta (TGF-beta) has been proposed to be critical in tissue repair mechanisms resulting from radiation injury. Previously, we showed that interruption of TGF-beta signaling by deletion of Smad3 results in resistance to radiation-induced injury. In the current study, a small molecular weight molecule, halofuginone (100 nm), is demonstrated by reporter assays to inhibit the TGF-beta signaling pathway, by Northern blotting to elevate inhibitory Smad7 expression within 15 min, and by Western blotting to inhibit formation of phospho-Smad2 and phospho-Smad3 and to decrease cytosolic and membrane TGF-beta type II receptor (TbetaRII). Attenuation of TbetaRII levels was noted as early as 1 h and down-regulation persisted for 24 h. Halofuginone blocked TGF-beta-induced delocalization of tight junction ZO-1, a marker of epidermal mesenchymal transition, in NMuMg mammary epithelial cells and suggest halofuginone may have in vivo anti-fibrogenesis characteristics. After documenting the in vitro cellular effects, halofuginone (intraperitoneum injection of 1, 2.5, or 5 microg/mouse/day) efficacy was assessed using ionizing radiation-induced (single dose, 35 or 45 Gy) hind leg contraction in C3H/Hen mice. Halofuginone treatment alone exerted no toxicity but significantly lessened radiation-induced fibrosis. The effectiveness of radiation treatment (2 gray/day for 5 days) of squamous cell carcinoma (SCC) tumors grown in C3H/Hen was not affected by halofuginone. The results detail the molecular effects of halofuginone on the TGF-beta signal pathway and show that halofuginone may lessen radiation-induced fibrosis in humans.

Combination therapy of tetracycline and tacrolimus resulting in rapid resolution of steroid-induced periocular rosacea

Standard treatment of steroid-induced rosacea includes discontinuation of steroids and use of an oral tetracycline. A temporary decrease to a lower-potency steroid prior to discontinuation remains optional. The limitations of standard therapy include a prolonged course of treatment with exacerbations prior to permanent improvement. Our challenge was to identify a treatment regimen to resolve steroid-induced periocular rosacea quickly and with minimal rebound effect.

Inhibitory actions of genistein in human breast cancer (MCF-7) cells

Genistein, a natural isoflavanoid phytoestrogen, is thought to be the active ingredient in soy that possesses breast cancer preventive properties. The molecular mechanisms that are involved in its cancer preventive properties have not been completely understood. The present study is designed to investigate the mechanism involved in the inhibitory action of genistein in MCF-7 cells. Genistein at 50 and 100 microM significantly arrested the growth of MCF-7 cells at G2/M phase (P<0.05) and decreased at the proliferative S phase (P<0.05). Using cDNA microarray technology, genes differentially regulated by genistein were identified. In particular, as confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR), genistein up-regulated heat shock protein 105 (HSP) mRNA and down-regulated mRNA expression of serum response factor (SRF), estrogen receptor (ER) alpha, disabled homolog 2 (DOC 2) and recombination activation gene 1 (RAG-1). Using real time RT-PCR, we have shown that HSP and SRF mRNA were both regulated by genistein in a time- and dose-dependent manner; however, it appears that only the effect of genistein on SRF mRNA, but not HSP mRNA expression, can be partially abolished by cotreatment with estrogen antagonist ICI 182,780. Western blotting analysis showed that the expressions of the ERalpha and SRF protein decreased significantly with genistein treatment (P<0.05). These results suggest that the inhibitory action of genistein on human breast cancer cells appears to be complex and is only partially mediated by the alteration of estrogen receptor-dependent pathways.

Halofuginone to treat fibrosis in chronic graft-versus-host disease and scleroderma

Chronic graft-versus-host disease (cGvHD) and systemic sclerosis (scleroderma [SSc]) share clinical characteristics, including skin and internal organ fibrosis. Fibrosis, regardless of the cause, is characterized by extracellular matrix deposition, of which collagen type I is the major constituent. The progressive accumulation of connective tissue results in destruction of normal tissue architecture and internal organ failure. In both SSc and cGvHD, the severity of skin and internal organ fibrosis correlates with the clinical course of the disease. Thus, there is an unmet need for well-tolerated antifibrotic therapy. Halofuginone is an inhibitor of collagen type I synthesis in cells derived from various tissues and species and in animal models of fibrosis in which excess collagen is the hallmark of the disease. Halofuginone decreased collagen synthesis in the tight skin mouse (Tsk) and murine cGvHD, the 2 experimental systems that show many features resembling those of human GvHD. Inhibition of collagen synthesis by halofuginone is achieved by inhibiting transforming growth factor beta-dependent Smad3 phosphorylation. Dermal application of halofuginone caused a decrease in collagen content at the treated site of a cGvHD patient, and reduction in skin scores was observed in a pilot study with SSc patients. The results of the human studies provide basis for using halofuginone treatment for dermal fibrosis. As a first step toward future treatment of internal organ involvement, an oral administration study was performed in which halofuginone was well tolerated and plasma levels surpassed the predicted therapeutic exposure.

Worldwide assessment of linezolid's clinical safety and tolerability: comparator-controlled phase III studies

Linezolid, an oxazolidinone antibiotic, has 100% oral bioavailability and favorable activities against gram-positive pathogens including multidrug-resistant staphylococci, enterococci, and pneumococci. Safety assessments were conducted for 2,046 linezolid-treated patients and 2,001 comparator drug-treated patients from seven controlled clinical trials comparing the activities of linezolid and comparator drugs against nosocomial and community-acquired pneumonia, skin and skin structure infections, and methicillin-resistant staphylococcal infections. Drug-related adverse events were primarily transient. The most frequent (> or = 2%) adverse events caused by linezolid and the comparator drugs were diarrhea (4.3 and 3.2%, respectively; P = 0.074), nausea (3.4 and 2.3%, respectively; P = 0.036), and headache (2.2 and 1.3%, respectively; P = 0.047). Treatment discontinuations due to drug-related events (2.4 and 1.9%, respectively), serious adverse events (11.4 and 10.6%, respectively), and deaths (4.8 and 4.9%, respectively) were similar. No clinically significant drug-related hematologic events were reported, and laboratory safety data were comparable. In the first 6 months of postmarketing surveillance, hematologic abnormalities were reported in 0.1% of linezolid-treated patients, but no irreversible blood dyscrasias were documented. The risk for transient, reversible hematologic effects from treatment with linezolid should be considered together with the clinical benefits associated with its use.

Targeting bacterial virulence: the role of protein synthesis inhibitors in severe infections. Insights from the Society of Infectious Diseases Pharmacists

Morbidity and mortality due to certain bacterial pathogens have not declined despite the availability of effective antimicrobial treatments. Staphylococcus aureus and Streptococcus pyogenes cause a number of serious infections, such as necrotizing fasciitis and toxic shock syndrome, which are associated with the release of bacterial toxins. Animal studies have demonstrated clindamycin, a protein synthesis inhibitor, to be more effective in treating these severe infections than other more susceptible antimicrobial treatments. Linezolid, another protein synthesis inhibitor, also has shown efficacy in in vitro studies. Human trials to validate the effects of antibiotic therapies on bacterial virulence have not been performed. Future animal and human studies are needed to help elucidate the immunomodulatory mechanisms of protein synthesis inhibitors in order to optimize antimicrobial treatment and decrease the morbidity and mortality associated with severe bacterial infections.

[Macrolides, ketolides and streptogramins]

Macrolides, ketolides and streptogramins are three families of antibiotics with different chemical structures, sharing the same mechanism of action. All three bind to distinct bases of the peptidyl transferase center of ARNr 23S. Their antibacterial spectrum practically overlaps, but dissimilarities in affinity and/or number of binding sites determine differences in the intensity of their antibacterial effects (bacteriostatic or bactericidae) and in their activity against strains with acquired resistance mechanisms. These agents are active against the majority of gram-positive microorganisms and many intracellular microorganisms for growth. Over the last five years in our country, the percentage of macrolide-resistant pneumococci and S. pyogenes strains has increased substantially. Telithromycin (ketolide) and Synercid (streptogramin) have shown maintained activity against these strains. Macrolides, ketolides and streptogramins are metabolized in the liver through CYP 3A4 and they can partially block the activity of the enzyme, interfering with the metabolism of other drugs that use the same metabolic pathway. There is little elimination through the urine, with the exception of clarithromycin. High concentrations are reached in the cellular cytoplasm, but they do not diffuse to the CSF. These agents are included among class B drugs for use during pregnancy. Tolerance to macrolides and telithromycin is good and they have few associated adverse effects. The main clinical indication for these drugs is in empirical treatment of mild to moderate, community-acquired, upper and lower respiratory tract infections. Synercid is indicated in the treatment of infections due to methicillin-resistant staphylococci and glycopeptide-resistant enterococci.

Novel antibacterial agents for the treatment of serious Gram-positive infections

With the continuing development of clinical drug resistance among bacteria and the advent of resistance to the recently released agents quinupristin-dalfopristin and linezolid, the need for new, effective agents to treat multi-drug-resistant Gram-positive infections remains important. This review focuses on agents presently in clinical development for the treatment of serious multidrug-resistant staphylococcal, enterococcal and pneumococcal infections, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and penicillin-resistant Streptococcus pneumoniae. Agents to be discussed that affect the prokaryotic cell wall include the antimethicillin-resistant S. aureus cephalosporins BAL9141 and RWJ-54428, the glycopeptides oritavancin and dalbavancin and the lipopeptide daptomycin. Topoisomerase inhibitors include the fluoroquinolones gemifloxacin, sitafloxacin and garenoxacin. Protein synthesis inhibitors are represented by the ketolides telithromycin and cethromycin, the oxazolidinones and the glycylcycline tigecycline. Although each of these compounds has demonstrated antibacterial activity against antibiotic-resistant pathogens, their final regulatory approval will depend on an acceptable clinical safety profile.

[Oxazolidinones and glycopeptides]

We review the chemical structure, pharmacokinetics, antimicrobial spectrum, mechanisms of action and resistance, clinical use and adverse effects of oxazolidinones (linezolid) and glycopeptides. Oxazolidinones inhibit protein synthesis and glycopeptides cell wall synthesis. Antibacterial spectra cover grampositive pathogens, including multiresistant organisms. Linezolid has a 100% absorption and can be administered orally or intravenously; it is cleared by renal and hepatic routes, thus dose adjustments are not needed in moderate renal or hepatic failure. Oral absorption of glycopeptides is minimal. They are excreted by the kidneys (dose adjustments are needed in renal failure). The main clinical indications are the treatment of infections caused by grampositive pathogens; linezolid is also useful for infections caused by glycopeptide-resistant enterococcal infections. Linezolid can cause trombocytopenia when treatment lasted longer than two weeks. The main side effect of vancomycin is its nefrotoxicity and teicoplanin can cause fever.

Neuroprotective synergy of N-methyl-D-aspartate receptor antagonist (MK801) and protein synthesis inhibitor (cycloheximide) on spinal cord ischemia-reperfusion injury in rats

Thoraco-abdominal aortic surgery requiring temporal cross clamping of the aorta results in a high incidence of paraplegia due to temporary ischemia of the spinal cord. Both excitotoxicity and apoptosis are implicated in the pathogenesis of spinal cord ischemia-reperfusion injury. We propose that the N-methyl-D-aspartate receptor antagonist dizocilpine maleate (MK801) and the protein synthesis inhibitor cycloheximide produce a synergic effect in a rodent model of spinal cord ischemia-reperfusion injury. Injury was induced by 20 min of temporal thoracic aorta occlusion and distal blood volume reduction. After injury, the animals were treated with vehicle, MK801, cycloheximide or MK801 and cycloheximide. Hind limb motor function recovery was better in the MK801 and combined therapy groups than in the control and cycloheximide groups. The mean neuronal survival rate of the control group was 45.3 +/- 3.2% on the 7(th) day after injury. In the MK801 and cycloheximide treatment groups, neuronal survival increased to 62.4 +/- 3.6% and 54.1 +/- 2.4%, respectively. For the combined therapy group, neuronal survival increased to 75.6 +/- 2.5%. The number of apoptotic cells in the control group was 211.4 +/- 8.8 per section on the 7th day after ischemic insult, while apoptosis was significantly reduced in the cycloheximide (96.8 +/- 6.7 cells) and combined (84.8 +/- 8.5 cells) groups. It was unchanged in the MK801 group (209.8 +/- 5.4 cells). These results suggest that combined treatments directed at blocking both N-methyl-D-aspartate receptor-mediated excitotoxic necrosis and caspase-mediated apoptosis might have synergic therapeutic potential in reducing spinal cord ischemia-reperfusion injury.

Autologous blood cell transplantation in multiple myeloma: impact of CD34+ cell selection with long follow-up

Positive CD34(+) selection to purge blood cell harvests is one way to attempt to reduce the high relapse risk after high-dose chemotherapy (HDT) supported by autologous blood cell transplantation (ABCT) in patients with multiple myeloma (MM). Until recently, however, the impact of CD34(+) selection, if any, on long-term clinical outcome in MM has remained obscure. We have analyzed engraftment kinetics, response to HDT, progression-free survival (PFS), and overall survival (OS) for 64 consecutive MM patients who have been treated with up-front HDT plus ABCT at our institution between 1993 and 1998. Nonrandomized comparisons were made between transplants with unselected (39 patients) and CD34(+)-selected (25 patients) grafts. The engraftment kinetics, need of blood product support, discharge time from hospital, and response to HDT were similar for both unselected and selected transplants. The median PFS was also similar (26 and 30 months, respectively) for the both groups. With a median follow-up time for the survivors of 67.5 months, the median OS (78 and 75 months, respectively) did not differ between transplants with unselected and selected grafts. In conclusion, this nonrandomized study suggests that positive CD34(+) selection has no beneficial impact on long-term outcome of patients with MM.

Small-molecule inhibitors of the cell cycle: an overview

Potent and selective small-molecule mediated inhibition of the cell's replication machinery remains a principal aim in the development of novel therapeutics and biological probes. Recent efforts have identified small molecules capable of arresting the cell cycle via specific interaction with a variety of intracellular protein targets. Advances in combinatorial and diversity oriented synthetic methods, coupled with a continued effort to identify sources of bioactive natural products, promise to contribute to the growing library of small-molecule inhibitors of the cell cycle.