The application of three-dimensional ultrasound to nuchal translucency measurement in early pregnancy (10-14 weeks): a preliminary study

OBJECTIVES

The aims of this prospective screening study were to calculate the success rate and to assess the intraoperator variability of fetal nuchal translucency measurement by using three-dimensional ultrasound.

SUBJECTS AND METHODS

Eighty-six women, each with a singleton pregnancy undergoing routine nuchal translucency measurement between 10 weeks and 14 weeks plus 6 days gestational age. Three-dimensional transvaginal sonography was performed. A new method of nuchal translucency measurement was applied from three volumetric data sets using four steps.

RESULTS

In all cases good sagittal views of the fetus were obtained, the fetal skin could be distinguished from the amnion and the nuchal translucency thickness could be measured. The new measurement procedure could be standardized. The overall time required for the examination was 5 min. The procedure caused no discomfort to the woman and was easily performed by the examiner. Intra-operator variability was low (P = 0.862).

CONCLUSION

Three-dimensional ultrasound is a useful and easily applicable tool for nuchal translucency measurement during early pregnancy (10-14 weeks plus 6 days). Its advantages still need further evaluation.

The possible cost effectiveness of peripheral blood stem cell mobilization with cyclophosphamide and the late addition of G-CSF

The purpose of this study was to develop a cost-effective protocol for the mobilization of peripheral blood stem cells (PBSC) in patients with malignancy. Thirty consecutive patients were randomized to mobilize PBSC with the late addition of a standard 250 microg dose of G-CSF (Neutrogen) from day 8 or early addition of the same dose of G-CSF from day 2, following cyclophosphamide (CY) 4 g/m2. The median yield of CD34+ cells from evaluated patients was 7.87 x 10(6)/kg (range, 2.06-27.25), collected in a median of four apheresis (range, 2-9). Target CD34 + cell doses > or = 2.0 x 10(6)/kg were achieved in all patients able to be evaluated. There were no statistically significant differences in CD34+ cell yields or toxicities. Overall engraftment occurred with median days to neutrophils > or = 0.5 x 10(9)/L or platelets > 20 x 10(9)/L of 11 and 17 days, respectively. However, the duration of G-CSF administration was markedly shorter in the late use of G-CSF group than in the early use of G-CSF group, with a median of 9 days compared with 15 days (p<0.001). PBSC harvesting after priming with CY plus delayed use of G-CSF made it a safe and cost-effective procedure.

Phenotypes of flavin-containing monooxygenase activity determined by ranitidine N-oxidation are positively correlated with genotypes of linked FM03 gene mutations in a Korean population

A non-invasive urine analysis method to determine the in-vivo flavin-containing mono-oxygenase (FMO) activity catalysing N-oxidation of ranitidine (RA) was developed and used to phenotype a Korean population. FMO activity was assessed by the molar concentration ratio of RA and RANO in the bulked 8 h urine. This method was used to determine the FMO phenotypes of 210 Korean volunteers (173 men and 37 women, 110 nonsmokers and 100 smokers). Urinary RA/RANO ratio, representing the metabolic ratio and the reciprocal index of FMO activity, ranged from 5.67-27.20 (4.8-fold difference) and was not different between men and women (P = 0.76) or between smokers and nonsmokers (P = 0.50). The frequencies of RA/RANO ratios were distributed in a trimodal fashion. Among the 210 Korean subjects, 93 (44.3%) were fast metabolizers, 104 (49.5%) were intermediate metabolizers and 13 (6.2%) were slow metabolizers. Subsequently, the relationship between the ranitidine N-oxidation phenotypes and FMO3 genotypes, determined by the presence of two previously identified mutant alleles (Glu158Lys: FMO3/Lys158 and Glu308Gly: FMO3/Gly308 alleles) commonly found in our Korean population was examined. The results showed that subjects who were homozygous and heterozygous for either one or both of the FMO3/Lys158 and FMO3/Gly308 mutant alleles had significantly lower in-vivo FMO activities than those with homozygous wild-type alleles (FMO3/Glu158 and FMO3/Glu308) (P < 0.001, Mann-Whitney U-test). Furthermore, the FMO activities of subjects with either FMO3/Lys158 or FMO3/Gly308 mutant alleles were almost identical to those having both FMO3 mutant alleles (FMO3/Lys158 and FMO3/Gly308). These two mutant alleles located, respectively, at exons 4 and 7 in the FMO3 gene appeared to be strongly linked by cis-configuration in Koreans. Therefore, we concluded that presence of FMO3/Lys158 and FMO3/Gly308 mutant alleles in FMO3 gene is responsible for the low ranitidine N-oxidation (FMO3 activity) in our Korean population.

Antitumor agents. 199. Three-dimensional quantitative structure-activity relationship study of the colchicine binding site ligands using comparative molecular field analysis

Inhibitors of tubulin polymerization interacting at the colchicine binding site are potential anticancer agents. We have been involved in the synthesis of a number of colchicine site agents, such as thiocolchicinoids and allocolchicinoids, which are colchicine analogues, and 2-phenyl-quinolones and 2-aryl-naphthyridinones, which are the amino analogues of cytotoxic antimitotic flavonoids. The most cytotoxic of the latter compounds strongly inhibit binding of radiolabeled colchicine to tubulin, and these agents therefore probably bind in the colchicine site of tubulin. We have applied conventional CoMFA and q(2)-GRS CoMFA to identify the essential structural requirements for increasing the ability of these compounds to form tubulin complexes. The CoMFA model for the training set of 51 compounds yielded cross-validated R(2) (q(2)) values of 0.637 for conventional CoMFA and 0.692 for q(2)-GRS CoMFA. The predictive power of this model was confirmed by successful activity prediction for a test set of 53 compounds with known potencies as inhibitors of tubulin polymerization. The activities of 88% of the compounds were predicted with absolute value of residuals of less than 0.5. The predictive q(2) values were 0.546 for conventional CoMFA and 0.426 for q(2)-GRS CoMFA. The conventional CoMFA model with the highest predictive q(2) (0.546) was analyzed in detail in terms of underlying structure-activity relationships.

cDNA cloning of pig testicular lactate dehydrogenase-C, thermal stability of the expressed enzyme, and polymorphism among strains

Pig testicular lactate dehydrogenase-C (LDHC) cDNA was cloned and sequenced. The deduced sequence of 332 amino acids from pig LDHC shows 73% and 67% identity with that of pig LDHA (muscle) and LDHB (heart) respectively, whereas pig LDHA and LDHB isozymes shows 74% sequence identity. Pig and mouse LDHC cDNAs were subcloned into bacterial expression vector, and the expressed pig LDHC isozyme was shown to be as thermally stable as mouse LDHC isozyme. Pig genomic DNAs from Chinese Meishan, English Yorkshire, Danish Landrace and American Duroc were shown to exhibit polymorphic sites for restriction enzymes EcoRI, BamHI and PstI.

Diffusion-weighted MRI in vascular dementia

OBJECTIVE

To examine the ability of diffusion-weighted MRI (DWI) to detect ongoing cerebral ischemia in patients with vascular dementia (VaD).

BACKGROUND

VaD due to small-vessel disease results from the cumulative impact of recurrent cerebral ischemia. Cerebral ischemia may produce clinical manifestations, producing the "stepwise" decline characteristic of VaD. Conventional MRI can detect small regions of ischemic damage but cannot determine when injury developed. In contrast, DWI shows sensitivity in detecting ischemia of recent onset.

DESIGN/METHODS

Patients with VaD (n = 30) underwent DWI in addition to standard MRI sequences. Patients were divided into two groups according to the presence of new focal deficits or mental change within 10 days before MRI. In 10 patients of positive group, symptomatic neurologic decline occurred an average of 4.2 days before the imaging procedure.

RESULTS

Seven (70%) of 10 patients with a recent neurologic event showed 15 new regions of signal abnormality on DWI. The anatomic distribution of signal change could account for the patients' new symptoms or signs in all but one patient. Similar signal abnormality was detected in 4 (20%) of 20 patients without a recent neurologic event. New foci of altered signal intensity were distinguishable from prior injuries only with DWI. No significant difference was found between patients with and without DWI abnormalities in gender, age, Mini-Mental State Examination score, Hachinski Ischemic Score, vascular risk factors, or severity of increased signal on T2-weighted MRI scans.

CONCLUSION

Small foci of abnormal signal on diffusion-weighted MRI (DWI), presumably representing recent small infarcts, occur often in vascular dementia (VaD) from small-vessel disease, even in patients without a recent "stepwise decline." The results suggest that DWI might be used to monitor VaD progression in future observational and interventional studies of this disorder.

Localization of bcl-2 mRNA in the rabbit central nervous system

In this study, we demonstrated bcl-2 expression in the rabbit brain using in situ hybridization and compared the results with the studies done on the other animals. Although the bcl-2 expressions of the rabbit were generally similar to those of the other animals, some differences were also found; the cells in molecular and Purkinje cell layers of the cerebellum, which were bcl-2 negative in the others, showed intense bcl-2 positive signals, while the ependymal cells, arachnoid villi and granular layer, which were positive in the other animals, were not well stained with bcl-2 riboprobes in the rabbit brain. Our findings clearly showed the similarities and differences of rabbit bcl-2 mRNA as compared with the other species for the first time, and provided the basis of further study on the properties of bcl-2 in this species.

Activation of telomerase by silica in rat lung

By measuring the activity of telomerase in a silica-instilled rat lung, the study found a significant increase in telomerase activity compared to that of the control. Pneumoconiosis displays the characteristics of fibroblast-proliferation and accumulation of collagen, which finally causes the pathologic changes of irreversible and progressive fibrosis of the lung. On the basis of the hypothesis that cellular proliferation may trigger telomerase-activity, the experiment was carried out with telomerase-activation in silicosis. Silica-instilled rat lungs showed increased activity of telomerase, which was measured by TRAP (telomeric repeat amplification protocol) assay, at the time of the 1st, 5th and 8th week after intratracheal instillation of silica in vivo. However, no activity was shown in silica-co-cultured fibroblast in vitro. By summarizing these results, the activity of telomerase is thought to be a very sensitive marker for the evaluation of pathogenicity, showing cellular immortalization in an experimental silicosis model.

Anti-A isoagglutinin as a risk factor for the development of pure red cell aplasia after major ABO-incompatible allogeneic bone marrow transplantation

Delayed erythropoiesis and pure red cell aplasia (PRCA) have been reported after major ABO-incompatible BMT. We attempted to find risk factors for the development of PRCA in 27 patients who underwent major ABO-incompatible BMT. In all patients, the donor marrow was depleted of RBCs before infusion. In 22 patients, isoagglutinins were determined until they disappeared. In eight (29.6%) out of 27 patients, bone marrow examination following BMT showed the findings of PRCA. We analyzed various clinico-pathologic risk factors and isoagglutinin type was the only significant risk factor. Patients with anti-A isoagglutinins against donor RBC developed PRCA more frequently than patients with anti-B (8/17 vs 0/9). Median days to the disappearance of isoagglutinins tended to be longer in patients with PRCA (PRCA vsnon-PRCA, 200 vs 66 days) and in cases with anti-A isoagglutinins (anti-A vsanti-B, 160 vs 51 days). Times to disappearance of isoagglutinins correlated with times to reticulocytes over 1% and initial appearance of donor type RBC (R2 = 0.708 and 0.711). In conclusion, RBC engraftment following major ABO-incompatible BMT was dependent on the disappearance of isoagglutinins against donor RBC, and anti-A isoagglutinin was a risk factor for the development of PRCA after major ABO-incompatible allogeneic BMT. Bone Marrow Transplantation (2000) 25, 179-184.

Bioavailability of itraconazole in rats and rabbits after administration of tablets containing solid dispersion particles

A tablet dosage form containing solid dispersions of itraconazole (Asd tablets) was prepared by using the spray-drying and wet granulation methods. The dissolution rate of itraconazole from Asd tablets was fast, with more than 90% released within 10 min, compared to less than 20% for a marketed product, Sporanox capsules. The oral absorption of itraconazole from Asd tablets was determined in rats and rabbits and was compared with that for Sporanox capsules. In the rat, there was no difference between the Asd tablets and Sporanox capsules in the mean area under the curve (AUC) (3089.5 +/- 4332.8 ng.hr/ml and 3653.9 +/- 2348.9 ng.hr/ml, respectively) and Cmax (295.0 +/- 344.5 and 390.5 +/- 169.4 ng/ml, respectively). Also, in the rabbit, no difference was found between the two products in the mean AUC (AUMC; 19357.9 +/- 5117.5 ng.hr/ml and 23382.2 +/- 6236.5 ng.hr/ml, respectively) and Cmax (766.4 +/- 276.5 and 1127.5 +/- 577.9 ng/ml, respectively). Despite the rapid in vitro release characteristics of itraconazole from the Asd tablets, the in vivo absorption of itraconazole was comparable to that of Sporanox capsules, with no difference in Tmax in both animal species. Serum levels of the major active metabolite hydroxyitraconazole were also measured. Itraconazole was rapidly converted to hydroxyitraconazole in both rats and rabbits, but there were species-specific differences in their pharmacokinetics. It is concluded that, in addition to drug solubility and dissolution characteristics, other formulation factors such as the physical state of the drug and the granulation process, may also need to be considered in the prediction of the in vivo absorption of itraconazole based on in vitro data.

The role of superoxide ions in the degradation of synthetic absorbable sutures

The objective of this study was to examine the effect of superoxide ion-induced degradation on synthetic absorbable biomaterials. Synthetic absorbable sutures were used as the model compounds. Inflammatory cells, particularly leukocytes and macrophages, are able to produce highly reactive oxygen species, such as superoxide (. O(2)(-)), during inflammatory reactions to foreign materials. Superoxide ions may act as oxygen nucleophile agents to attack biomaterials. In this study, the changes in tensile breaking force, thermal properties, and the surface morphology of five commercial (2/0 in size) synthetic absorbable sutures (Dexon, Vicryl, PDS II, Maxon, and Monocryl) as a function of superoxide ion concentration at 25 degrees C for 24 h were studied. Among the five absorbable sutures and over the concentration range of this study, the monofilament Monocryl suture was the most sensitive toward superoxide ion-induced degradation, followed by Maxon, Vicryl, Dexon, and PDS II sutures. The amount of tensile breaking force loss over a 24 h period ranged from as low as 3% to as high as 80%, depending on the type of absorbable sutures, the reaction time, and the superoxide ion concentration. All five absorbable sutures showed significant reductions in both the T(m) and T(g). Unlike the surface morphological changes of absorbable sutures in conventional buffer solutions, the effect of superoxide ion-induced degradation on the surface morphologies of these five absorbable sutures was unique, particularly the moon-crater-shaped impressions of various sizes and depths found in Monocryl and Maxon sutures, which defied the anisotropic characteristics of fibers.

Vascular complications in lumbar spinal surgery: percutaneous endovascular treatment

Four patients underwent endovascular treatment of vascular injuries complicating lumbar spinal surgery. In two patients with massive retroperitoneal hemorrhage, the extravasating lumbar arteries were successfully embolized with microcoils. Two patients with large iliac arteriovenous fistula (AVF) were treated, one with embolization using a detachable balloon and coils, which failed, and the other with placement of a stent graft after embolization of distal runoff vessels, which occluded the fistula. We conclude that acute arterial laceration or delayed AVF complicating lumbar spinal surgery can be managed effectively with selective embolization or stent-graft placement, respectively.

Difference in the distribution pattern of Helicobacter pylori and grade of gastritis in the antrum and in the body between duodenal ulcer and benign gastric ulcer patients

OBJECTIVES

To investigate the relationship between the Helicobacter pylori (H. pylori) colonization and the grade of gastritis in the antrum and in the body of patients with duodenal ulcer (DU) or benign gastric ulcer (BGU).

METHODS

This study was performed in H. pylori-positive 220 DU patients and 180 BGU patients. H. pylori density was evaluated by modified Giemsa staining and CLO test, and gastritis grade was graded by H&E staining in the antrum and in the body.

RESULTS

H. pylori grade by Giemsa staining was 1.24 in the antrum and 0.82 in the body for DU group (p < 0.01), and those of BGU group were slightly reversed, 0.83 and 0.87, respectively, but without statistical significance. Similarly H. pylori grade by CLO test was 3.1 in the antrum and 2.8 in the body for DU group (p < 0.01), and those of BGU group 2.3 and 2.6 (p < 0.05), respectively. In contrast, gastritis grade was 1.7 in the antrum and 1.2 in the body for DU group (p < 0.01), and those of BGU group 1.6 and 1.3 (p < 0.01), respectively, similar to those of DU. However, there was a correlation between H. pylori grade and gastritis grade in the antrum and in the body, not only in DU but also in BGU group (p < 0.01).

CONCLUSION

In spite of different distribution patterns of H. pylori between DU group and BGU group, gastritis grade of the antrum was significantly higher than that of the body in both DU and BGU. However, gastritis is correlated with H. pylori density not only in DU but also in BGU patients. It looks like the inflammatory reaction to H. pylori is stronger in the antrum than in the body.

Expansion of tumor-T cell pairs from fine needle aspirates of melanoma metastases

Lymphocytes expanded from excised specimens can be used to characterize intratumoral T cell responses. These analyses, however, are limited to one time point in the natural history of the removed tumor. The expansion of autologous tumor cells and tumor-infiltrating lymphocytes (TIL) from fine needle aspirates (FNA) of tumors potentially allows a dynamic evaluation of T cell responses within the same lesion at moments relevant to the disease course or response to therapy. Fourteen TIL cultures and 8 tumor cell lines were generated from 18 FNA (12 patients). Five of six TIL that could be tested against autologous tumor demonstrated specific reactivity. Two additional TIL for which no autologous tumor was available demonstrated recognition of HLA-matched melanoma cell lines. Serial FNA of the same lesions were performed in five HLA-A*0201 patients vaccinated with the emulsified melanoma Ag (MA) epitopes: MART-1:27-35; tyrosinase:368-376(370D); gp100:280-288(288V); and gp100:209-217 (210M). FNA material was separately cultured for a short time in IL-2 (300 IU/ml) after stimulation with irradiated autologous PBMC pulsed with each peptide or FluM1:58-66 (1 micromol/ml). No peptide-specific TIL could be expanded from prevaccination FNA. However, after vaccination, TIL specific for gp100:280(g280), gp100:209 (g209), and MART-1:27-35 (MART-1)-related epitopes were identified in three, three, and two patients, respectively. No Flu reactivity could be elicited in TIL, whereas it was consistently present in parallel PBMC cultures. This excluded PBMC contamination of the FNA material. This analysis suggests the feasibility of TIL expansion from minimal FNA material and localization of vaccine-specific T cells at the tumor site.

Characterization of human lung cancer cells resistant to 4'-O-demethyl-4beta-(2"-nitro-4"-fluoroanilino)-4-desoxypodophyllotoxin , a unique compound in the epipodophyllotoxin antitumor class

A new semi-synthetic podophyllotoxin derivative, 4'-O-demethyl-4beta-2"-nitro-4"-fluoroanilino)-4-desoxypo dophyllotoxin (compound 1), an analog of GL-331 (compound 2), is a potent and broad-spectrum inhibitor of cultured human cancer and drug-resistant cell growth. In general, 4'-demethylepipodophyllotoxin analogs, including 2, exert anti-tumor activity by targeting the nuclear enzyme DNA topoisomerase II, but 1 is not an enzyme inhibitor. Unlike the cytotoxic activity of compound 2, cell killing by 1 is dose-limiting and a significant fraction of cells (30-40%) survive treatment. As an approach to investigate mechanism of action, 1-resistant A549 (human lung cancer) sub-lines were selected and characterized. Results of the work show that 1-resistant cells: (i) are moderately cross-resistant (2- to 3-fold) to various cytotoxic drugs via a P-glycoprotein-independent mechanism, (ii) have an altered growth habit, (iii) are deficient in normal attachment on plastic and collagen substrata, and (iv) have an altered plasma membrane protein composition including several proteins in the 140->200 kDa molecular mass range and a doublet of phosphoserine-containing proteins of about 135 kDa. Since 1 treatment of cells affects neither cellular attachment or membrane-protein phosphorylation, the changes observed in 1-resistant cells are interpreted as a survival response to drug action.

Asymmetric solid-phase synthesis of (3'R,4'R)-di-O-cis-acyl 3-carboxyl khellactones

[formula: see text] We describe a practical parallel synthesis of (3'R,4'R)-di-O-cis-acyl 3-carboxyl khellactones on a solid phase in high yield. The highlights of this synthesis include a Knoevenagel condensation, asymmetric dihydroxylation, catalyzed acylation, and product cleavage from the solid support.

A mathematical description of regulation of the G1-S transition of the mammalian cell cycle

A mathematical model of regulation of the G1-S transition of the mammalian cell cycle has been formulated to organize available experimental molecular-level information in a systematic quantitative framework and to evaluate the ability of this manifestation of current knowledge to calculate correctly experimentally observed phenotypes. This model includes nine components and includes cyclin-cdk complexes, a pocket protein (pRb), a transcription factor (E2F-1), and a cyclin-cdk complex inhibitor. Simulation of the model equations yields stable oscillatory solutions corresponding to cell proliferation and asymptotically stable solutions corresponding to cell cycle arrest (quiescence). Bifurcation analysis of the system suggests changes in the intracellular concentrations of either E2F or cyclin E can activate cell proliferation and that co-overexpression of these molecules can prevent cell proliferation. Further analysis suggests that the amount of inhibitor necessary to prevent cell proliferation is independent of the concentrations of cyclin E and E2F and depends only on the equilibrium ratio between the bound and unbound forms of the inhibitor to the complex.

Functional analysis of antigen-specific T lymphocytes by serial measurement of gene expression in peripheral blood mononuclear cells and tumor specimens

The cloning of cancer Ags recognized by T cells has provided potentially new tools to enhance immunity against metastatic cancer. The biological monitoring of effective immunization has, however, remained a dilemma. We describe here a sensitive molecular quantitation methodology that allows analysis of in vivo immune response to vaccination. Metastatic melanoma patients were immunized with a synthetically modified peptide epitope (209-2M) from the melanoma self-Ag gp100. Using serial gene expression analysis, we report functional evidence of vaccine-induced CTL reactivity in fresh cells obtained directly from the peripheral blood of postimmunized patients. Further, we demonstrate in vivo localization of vaccine-induced immune response within the tumor microenvironment. The results of these molecular assays provide direct evidence that peptide immunization in humans can result in tumor-specific CTL that localize to metastatic sites.

Mechanism of silica- and titanium dioxide-induced cytotoxicity in alveolar macrophages

Particles can cause cytotoxicity in pulmonary alveolar macrophages (AM). Several mechanisms to explain this cytotoxicity have been suggested. However, the exact mechanism of particle-induced cytotoxicity in AM remains to be established. Silica and TiO2 produced a concentration-dependent cytotoxicity as evidenced by loss of cell viability and fall in ATP levels. While silica induced a greater cytotoxicity, TiO2 produced a higher reduction in ATP levels. Silica increased the release of LDH, but TiO2 did not affect enzymatic release. TiO2 suppressed succinate-triggered oxygen consumption, whereas silica did not markedly change the effect of succinate on oxygen consumption. Polyinosinic acid (PI), a ligand of the scavenger receptor, inhibited the TiO2-induced fall in ATP content, but could not prevent the effect of silica on cellular ATP content. Data suggest that silica and TiO2 can induce cytotoxicity in AM, probably through different mechanisms.

Antitumor agents 201. Cytotoxicity of harmine and beta-carboline analogs

Twenty-six beta-carbolines were evaluated for in vitro cytotoxicity in a human tumor cell line panel. Harmine (3) showed significant activity against several cell lines including three drug-resistant KB sublines with various resistance mechanisms. Alpha-(4-nitrobenzylidine) harmine (16) had a broad cytotoxicity spectrum (ED50 values from 0.3-1.2 microg/mL against 1A9, KB, SaOS-2, A549, SK-MEL-2, U-87-MG, and MCF-7 cells).

Clofilium, a potassium channel blocker, induces apoptosis of human promyelocytic leukemia (HL-60) cells via Bcl-2-insensitive activation of caspase-3

We have demonstrated that clofilium, a potassium channel blocker, induces apoptosis on human promyelocytic leukemia (HL-60) cells. Cells treated with clofilium led to suppression of viability and proliferation in both time and concentration-dependent manners. Nuclear DAPI staining and electronmicroscopic examination revealed typical nuclear features of apoptosis in cells treated with clofilium that was further verified in DNA fragmentation analysis. Flow cytometry analysis with FITC-annexin V and propidium iodide (PI) revealed that apoptotic cell population with Annexin V+/PI- increased gradually from < 2% at 0 h, to 20% at 4 h and 29% at 16 h after exposure to 10 microM clofilium in HL-60 cells. Furthermore, fluorometric immunosorbent enzyme assay for activity of caspase-3 showed approximately a 10-fold increase of activity in cells treated with 10 microM of clofilium for 2-3 h compared with the basal level of its activity in untreated control cells. Immunoblotting analysis revealed proteolytic cleavage of caspase-3 and subsequent cleavage of PARP. However, there was no significant change of Bcl-2 and Bax proteins. These results indicate that clofilium exerts antiproliferative action and growth inhibition on HL-60 through induction of apoptosis which is mediated via Bcl-2-insensitive activation of caspase-3, and suggest chemotherapeutic and cytostatic potentials of this compound in human leukemias.

Synthesis of novel unnatural amino acid as a building block and its incorporation into an antimicrobial peptide

Considering the biological mechanism and in vivo stability of antimicrobial peptides, we designed and synthesized novel unnatural amino acids with more positively charged and bulky side chain group than lysine residue. The unusual amino acids, which were synthesized by either solution phase or solid phase, were incorporated into an antimicrobial peptide. Its effect on the stability, activity, and the structure of the peptide was studied to evaluate the potential of these novel unnatural amino acids as a building block for antimicrobial peptides. The incorporation of this unusual amino acid increased the resistance of the peptide against serum protease more than three times without a decrease in the activity. Circular dichroism spectra of the peptides indicated that all novel unnatural amino acids must have lower alpha helical forming propensities than lysine. Our results indicated that the unnatural amino acids synthesized in this study could be used not only as a novel building block for combinatorial libraries of antimicrobial peptides, but also for structure-activity relationship studies about antimicrobial peptides.

Effect of D-amino acid substitution on the stability, the secondary structure, and the activity of membrane-active peptide

Several diastereomers and an enantiomer of KKVVFKVKFKK, an antimicrobial peptide that acts on the lipid membrane of pathogens were synthesized to investigate the effect of D-amino acid substitution on stability, secondary structure, and activity. The stability of the peptide in serum was improved greatly by the D-amino acid substitutions. D-Amino acid substitutions at the N- and/or C-terminal of the peptide, which had little effect on the alpha-helical structure, and all D-amino acid substitutions that formed a left-handed alpha-helix maintained antimicrobial activity, whereas D-amino acid substitutions in the middle of the amino acid sequence disrupted the alpha-helical structure, resulting in the complete loss of activity. This result confirmed that the peptide did not interact with chiral receptors, enzymes, or any chiral component of the membrane. D-Amino acid substitutions at the termini reduced the inhibition of the activity by heat-inactivated serum, which indicated that local change of chirality or change of secondary structure induced by D-amino acid substitutions might affect the interactions between the peptide and certain components in the serum. The present study suggests that partial D-amino acid substitution is a useful technique to improve the in vivo activity of antimicrobial peptides.