Carbohydrate specificity of a lectin isolated from the fungus Sclerotium rolfsii

In order to investigate the functional roles of a phytopathogenic fungal lectin (SRL) isolated from the bodies of Sclerotium rolfsii, the binding properties of SRL were studied by enzyme linked lectinosorbent assay and by inhibition of SRL-glycan interaction. Among glycoproteins (gp) tested for binding, SRL reacted strongly with GalNAc alpha1-->4Ser/Thr (Tn) and/or Gal beta1-->3GalNAc alpha1-->(T(alpha)) containing gps: human T(alpha) and Tn glycophorin, asialo salivary gps, and asialofetuin, but its reactivity toward sialylated glycoproteins was reduced significantly. Of the sugar ligands tested for inhibition of SRL-asialofetuin binding, Thomsen-Friedenreich residue (T(alpha)) was the best, being 22.4 and 2.24 x 10(3) more active than GalNAc and Gal beta1--> residues, respectively. Other ligands tested were inactive. When the glycans used as inhibitors, T(alpha), and/or Tn containing gps, especially asialo PSM, asialo BSM, asialo OSM, active antifreeze gp, asialo glycophorin and Tn-glycophorin were very active, and 1.0 x 10(4) times more potent than GalNAc. From these results, it is clear that the combining site of SRL should be of a cavity type and recognizes only Tn and T(alpha) residues of glycans; it is suggested that T(alpha) and Tn glycotopes, which are present only in abnormal carbohydrate sequences of higher orders of mammal, are the most likely sites for phytopathogenic fungal attachment as an initial step of infection. The affinity of SRL for ligands can be ranked in decreasing order as follows: multivalent T(alpha) and Tn >> monomeric T(alpha) and Tn > GalNAc >>> II (Gal beta1-->4GlcNAc), L (Gal beta1-->4Glc), and Gal.

Antioxidant activity of extracts from Acacia confusa bark and heartwood

The antioxidant activity of extracts from bark and heartwood of Acacia confusa was evaluated by various antioxidant assays, including free radical and superoxide radical scavenging assays and lipid peroxidation assay as well as hydroxyl radical-induced DNA strand scission assay. In addition, an ex vivo antioxidant assay using a flow cytometric technique was also employed in this study. The results indicate that both bark and heartwood extracts clearly have strong antioxidant effects. Similar inhibitory activities for each test sample were found for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical generation and lipid peroxidation. As for the superoxide radical scavenging activity, the heartwood extract was more effective than the bark extract. Furthermore, the heartwood extract protected PhiX174 supercoiled DNA against strand scission induced by ultraviolet photolysis of H2O2, and it reduced the amounts of intracellular hydrogen peroxide, a reactive oxygen species, when it was co-incubated with human promyelocytic leukemia (HL-60) cells under oxidative stress.

Further characterization of apolipoprotein B genetic variations in Taiwanese

Apolipoprotein B (apoB, protein; APOB, gene) is the main protein component of low-density lipoprotein (LDL) and plays an important role in blood lipid metabolism. Previously, we have reported four APOB coding regions, 5' signal peptide, and 3' repeat sequence polymorphisms in our population. In this report, we further characterize other APOB genetic variations. The results illustrate that the mutation frequencies for Arg3500Gln (1/846 alleles), Arg4019Trp (2/786 alleles), -265 C/T promoter region (0/264 alleles), and intron 2 A/G (0/450 alleles) are very low. Our population showed a frequency of 68.9% for the B4311 Ser allele. The B4311 Asn allele was associated with a higher apoB level than the Ser group (p < 0.05) in normal controls. In the normal controls, a higher B4311 Asn/Asn genotype frequency was found in the group with total cholesterol (TC) > 200 mg/dL and apoB concentration > 85 mg/dL than in the group with a TC < 200 mg/dL and apoB < 85 mg/dL (p = 0.03 for TC comparison).

Cosmology from MAXIMA-1, BOOMERANG, and COBE DMR cosmic microwave background observations

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE DMR, provide consistent and high signal-to-noise measurements of the cosmic microwave background power spectrum at spherical harmonic multipole bands over 2<l less similar to 800. Analysis of the combined data yields 68% (95%) confidence limits on the total density, Omega(tot) approximately 1.11+/-0.07 (+0.13)(-0.12), the baryon density, Omega(b)h(2) approximately 0.032(+0.005)(-0.004) (+0.009)(-0.008), and the scalar spectral tilt, n(s) approximately 1.01(+0.09)(-0.07) (+0.17)(-0.14). These data are consistent with inflationary initial conditions for structure formation. Taken together with other cosmological observations, they imply the existence of both nonbaryonic dark matter and dark energy in the Universe.

Identification of a novel steroid derivative, NSC12983, as a paclitaxel-like tubulin assembly promoter by 3-D virtual screening

By flexibly docking 9593 compounds of the NCI-3D database against the refined structure of beta-tubulin using DOCK 4.0, a long-forgotten synthetic steroid derivative, NSC12983, has been identified as a microtubule-stabilizing agent. The 32 top scorers includes NSC12983 and the three added references: paclitaxel, docetaxel and IDN5109. That is, 12.5% of the 0.33% top scorers are active. In addition, NSC12983 is active on Mycobacterium tuberculosis in vitro and in vivo, which might be due to its ability to promote the assembly of essential cell division protein.

Solution structure of a type I dockerin domain, a novel prokaryotic, extracellular calcium-binding domain

The type I dockerin domain is responsible for incorporating its associated glycosyl hydrolase into the bacterial cellulosome, a multienzyme cellulolytic complex, via its interaction with a receptor domain (cohesin domain) of the cellulosomal scaffolding subunit. The highly conserved dockerin domain is characterized by two Ca(2+)-binding sites with sequence similarity to the EF-hand motif. Here, we present the three-dimensional solution structure of the 69 residue dockerin domain of Clostridium thermocellum cellobiohydrolase CelS. Torsion angle dynamics calculations utilizing a total of 728 NOE-derived distance constraints and 79 torsion angle restraints yielded an ensemble of 20 structures with an average backbone r.m.s.d. for residues 5 to 29 and 32 to 66 of 0.54 A from the mean structure. The structure consists of two Ca(2+)-binding loop-helix motifs connected by a linker; the E helices entering each loop of the classical EF-hand motif are absent from the dockerin domain. Each dockerin Ca(2+)-binding subdomain is stabilized by a cluster of buried hydrophobic side-chains. Structural comparisons reveal that, in its non-complexed state, the dockerin fold displays a dramatic departure from that of Ca(2+)-bound EF-hand domains. A putative cohesin-binding surface, comprised of conserved hydrophobic and basic residues, is proposed, providing new insight into cellulosome assembly.

Membrane instability in late-stage erythropoiesis

During maturation of the red blood cell (RBC) from the nucleated normoblast stage to the mature biconcave discocyte, both the structure and mechanical properties of the cell undergo radical changes. The development of the mechanical stability of the membrane reflects underlying changes in the organization of membrane-associated cytoskeletal proteins, and so provides an assessment of the time course of the development of membrane structural organization. Membrane stability in maturing erythrocytes was assessed by measuring forces required to form thin, tubular, lipid strands (tethers) from the surfaces of mononuclear cells obtained from fresh human marrow samples, marrow reticulocytes, circulating reticulocytes, and mature erythrocytes. Cells were biotinylated and manipulated with a micropipette to form an adhesive contact with a glass microcantilever, which gave a measure of the tethering force. The cell was withdrawn at controlled velocity and aspiration pressure to form a tether from the cell surface. The mean force required to form tethers from marrow reticulocytes and normoblasts was 27 +/- 9 pN, compared to 54 +/- 14 pN for mature cells. The energy of dissociation of the bilayer from the underlying skeleton increases 4-fold between the marrow reticulocyte stage and the mature cell, demonstrating that the mechanical stability of the membrane is not completely established until the very last stages of RBC maturation.

In situ identification of polyphosphate- and polyhydroxyalkanoate-accumulating traits for microbial populations in a biological phosphorus removal process

Polyphosphate- and polyhydroxyalkanoate (PHA)-accumulating traits of predominant microorganisms in an efficient enhanced biological phosphorus removal (EBPR) process were investigated systematically using a suite of non-culture-dependent methods. Results of 16S rDNA clone library and fluorescence in situ hybridization (FISH) with rRNA-targeted, group-specific oligonucleotide probes indicated that the microbial community consisted mostly of the alpha- (9.5% of total cells), beta- (41.3%) and gamma- (6.8%) subclasses of the class Proteobacteria, Flexibacter-Cytophaga (4.5%) and the Gram-positive high G+C (HGC) group (17.9%). With individual phylogenetic groups or subgroups, members of Candidatus Accumulibacter phosphatis in the beta-2 subclass, a novel HGC group closely related to Tetrasphaera spp., and a novel gamma-proteobacterial group were the predominant populations. Furthermore, electron microscopy with energy-dispersive X-ray analysis was used to validate the staining specificity of 4,6-diamino-2-phenylindole (DAPI) for intracellular polyphosphate and revealed the composition of polyphosphate granules accumulated in predominant bacteria as mostly P, Ca and Na. As a result, DAPI and PHA staining procedures could be combined with FISH to identify directly the polyphosphate- and PHA-accumulating traits of different phylogenetic groups. Members of Accumulibacter phosphatis and the novel gamma-proteobacterial group were observed to accumulate both polyphosphate and PHA. In addition, one novel rod-shaped group, closely related to coccus-shaped Tetrasphaera, and one filamentous group resembling Candidatus Nostocoidia limicola in the HGC group were found to accumulate polyphosphate but not PHA. No cellular inclusions were detected in most members of the alpha-Proteobacteria and the Cytophaga-Flavobacterium group. The diversified functional traits observed suggested that different substrate metabolisms were used by predominant phylogenetic groups in EBPR processes.

Clonality analysis using X-chromosome inactivation patterns by HUMARA-PCR assay in female controls and patients with idiopathic thrombocytosis in Taiwan

OBJECTIVE

Analysis of X-chromosome inactivation patterns (XCIPs) is a useful tool in the diagnosis of clonal disorders. The human androgen receptor (HUMARA) locus is especially useful for clonality study. The present study was conducted 1) to determine the heterozygosity rate for HUMARA locus in Taiwanese women, 2) to determine the frequency of excessive skewing in different cell types, and 3) to determine the utility of XCIPs in the differential diagnosis of thrombocytosis.

PATIENTS AND METHODS

XCIPs by HUMARA-PCR assay were performed on purified granulocytes and T cells from 73 female patients presenting with idiopathic persistent thrombocytosis (IT), 10 patients with reactive thrombocytosis (RT), and 46 bone marrow samples from female controls. XCIPs of buccal mucosa cells were also compared with those of T cells in 57 patients with IT. The percentage of clonal granulocytes was calculated after correcting for the degree of Lyonization in T cells.

RESULTS

The heterozygosity rate for the HUMARA gene was 89.1% in Taiwanese females. The median age of informative IT patients and controls was 59 (18-92) and 58 (19-89), respectively. Excessive skewing (allele ratio <0.33) was more frequent in granulocytes than in T cells in both controls (12/43 vs 9/43, p = 0.080) and IT patients (56/64 vs 25/64, p < 0.001). XCIPs were the same for both buccal mucosa and T cells in 43 patients but were different in 14 patients. Of the 43 informative controls, 31 had a polyclonal pattern; an ambiguous pattern was found in nine; and the remaining three, aged 71, 73, and 80, respectively, had a clonal pattern. A clonal pattern was found in 42 IT patients, a polyclonal pattern in 12, and an ambiguous pattern in 10 of the 64 IT patients. The frequency of clonal, polyclonal, and ambiguous patterns in the 40 IT patients with age < or = 65 was 55.0%, 30.0%, and 15.0%, respectively. None of the IT patients aged >65 had a polyclonal disease. IT patients aged >65 had a significantly higher frequency of clonal pattern (p = 0.030) and a significantly lower frequency of polyclonal pattern (p = 0.002) than those with age <65. Of the eight heterozygous patients with RT, one aged 80 exhibited a clonal pattern, and the remaining seven had a polyclonal pattern.

CONCLUSIONS

The present study on Taiwanese females showed a heterozygosity rate of 89.1% for the HUMARA gene. Our results confirmed that IT is a heterogeneous disorder in terms of clonality. Twenty-three percent of IT patients exhibited a greater than 20% difference in allele expression for buccal mucosa and T cells. Presence of a clonal XCIP in young patients with IT can serve as a positive marker for the diagnosis of clonal thrombocytosis, and elderly patients with polyclonal XCIPs are unlikely to have essential thrombocythemia.

A cDNA from human bone marrow encoding a protein exhibiting homology to the ATP1gamma1/PLM/MAT8 family of transmembrane proteins

A cDNA clone, IWU-1, was cloned from human bone marrow. Its putative open reading frame encoded a protein of 115 amino acids with a calculated molecular mass of 12.9 kDa. The deduced amino acid sequence exhibited high homology (>68%) to members of the ATP1gamma1/PLM/MAT8 family of single transmembrane proteins, primarily in the region containing the putative transmembrane domain. The sequence at the amino-terminal side exhibited high homology (>61%) to the cytoplasmic region of the angiotensin II type 1 receptors.

Quantitative assessment of phagocytic activity of hemocytes in the prawn, Penaeus merguiensis, by flow cytometric analysis

BACKGROUND

The blood cells of crustaceans are involved in phagocytosis of invading microorganisms, contributing to their defense mechanisms. In this study, phagocytic activity of hemocytes of the prawn, Penaeus merguiensis, was quantitated by means of flow cytometric analysis.

METHOD

This study was done in vitro. Hemolymph, which was extracted from prawns, was mixed with an equal volume of anticoagulant. Heat-killed Escherichia coli prestained with propidium iodide (PI) was then added. Hemocytes were fixed at various time intervals for flow cytometric analysis. This study was supplemented with electron micrographs using transmission electron microscopy (TEM), which showed three populations of hemocytes.

RESULTS

It was observed that those hemocytes that were more active engulfed and digested bacteria readily, thus having higher red fluorescence intensity. The phagocytic activity was expressed as fluorescence unit or engulfed E. coli number per hemocyte.

CONCLUSIONS

With this approach, the phagocytic and cellular activity of individual hemocyte populations could be studied quantitatively.

A model for the interaction of paclitaxel with the Bcl-2 loop domain: a chemical approach to induce conformation-dependent phosphorylation

A homology model for human Bcl-2 was built. Paclitaxel and baccatin III were individually docked into the Bcl-2 loop domain. The conformational space of the loop region on ligand binding was explored by molecular dynamics. The ligand-Bcl-2 interaction energy was calculated by minimization in the binding site. It was found that both paclitaxel's core skeleton and its C-13 side chain contribute significantly to its interaction with Bcl-2. A portion of the Bcl-2 loop domain was found to be locked by the bound paclitaxel and baccatin III in a similar conformation.

Expression of mPer1 and mPer2, two mammalian clock genes, in murine bone marrow

Although circadian variations in hematopoiesis have been well documented, the molecular mechanism of the circadian rhythms remains elusive. To determine if a clock system exists in bone marrow to mediate the circadian rhythms, we analyzed the expression of mPer1 and mPer2, both mouse homologues of the Drosophila period gene and known regulators of the clock system, in murine bone marrow by relative quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). We demonstrated that both genes were expressed in bone marrow. Furthermore, the expression patterns of mPer1 and mPer2 in total bone marrow cells exhibited two peaks over a 24-h period. In contrast, the expression patterns of these two genes in the Gr-1-positive cells isolated from bone marrow mainly contributed to one of the two peaks. These results indicate that a clock system exists in bone marrow and suggest that the circadian rhythms in bone marrow are lineage- and/or differentiation stage-dependent.

Felodipine does not increase the reflux episodes in patients with gastroesophageal reflux disease

BACKGROUND/AIMS

Calcium channel blocking agents have been reported to increase the risk of gastroesophageal reflux. However, whether felodipine, a newer calcium channel blocker, increases reflux episodes and decreases esophageal acid clearance in patients with gastroesophageal reflux disease has never been studied. Therefore, the aim of this study was to evaluate whether felodipine increases the incidence of gastroesophageal reflux in patients with gastroesophageal reflux disorder.

METHODOLOGY

Nine patients with gastroesophageal reflux disease, 6 men and 3 women, with a mean age of 62.6 +/- 14.4 years (range: 37-80 years) were studied. They received ambulatory esophageal pH monitoring for 45.7-48 hours (mean: 47.1 +/- 0.8 hours). Various pH parameters were evaluated during a similar interval of monitoring time before and after receiving 5 mg of felodipine.

RESULTS

No significant difference was noted in any pH parameter by the Wilcoxon signed Ranks test, including reflux episodes (P = 0.552), reflux episodes longer than 5 min (P = 0.683), esophageal acid clearance (P = 0.663) and fraction time of pH < 4 (P = 0.752) before and after the use of felodipine.

CONCLUSIONS

Felodipine does not increase reflux episodes or impair esophageal acid clearance in patients with gastroesophageal reflux disease.

Immunoglobulin D multiple myeloma

BACKGROUND

Immunoglobulin D (IgD) multiple myeloma (MM) is rare, accounting for less than 2% of all patients with MM in Western countries. In Taiwan, the frequency and clinicopathologic features of IgD MM have not yet been reported.

METHODS

The clinicopathologic features and treatment outcome of patients with IgD MM diagnosed between January 1, 1982, and December 31, 1998, in Chang Gung Memorial Hospital were retrospectively reviewed. Nineteen patients with IgD MM were diagnosed. Of those patients, the medical records of 16 were available for review.

RESULTS

Most of the patients were male (11/16) with a median age of 59 years. The most common presenting features included bone pain (56%), gastrointestinal discomfort (38%), general malaise (38%), and body weight loss (25%). The majority of patients had cytopenia (88%), renal function impairment (75%), hypercalcemia (63%), hyperuricemia (69%), elevated beta 2-microglobulin levels (86%), and Bence Jones proteinuria (92%). Serum protein electrophoresis showed an M-peak in 9 cases (9/12), whereas immunoelectrophoresis or immunofixation identified an IgD monoclonal gammopathy in all 16 patients. All of the M-proteins were of a lambda-light chain type. The IgD level ranged between 584 and 129,000 IU/ml (normal, < 100 IU/ml). All the patients had stage III disease except one (stage I). Four patients were still alive at the time of this analysis. The median survival time was 12 months. Infection was the leading cause of death (50%).

CONCLUSION

The present series showed that IgD MM had aggressive clinical features, male predominance, a high frequency of renal function impairment, high incidence of M-protein undetected by serum protein electrophoresis, a predilection for lambda-light chains, and a short period of survival.

Secondary structure and calcium-induced folding of the Clostridium thermocellum dockerin domain determined by NMR spectroscopy

Assembly of the cellulosome, a large, extracellular cellulase complex, depends upon docking of a myriad of enzymatic subunits to homologous receptors, or cohesin domains, arranged in tandem along a noncatalytic scaffolding protein. Docking to the cohesin domains is mediated by a highly conserved domain, dockerin (DS), borne by each enzymatic subunit. DS consists of two 22-amino-acid duplicated sequences, each bearing homology to the EF-hand calcium-binding loop. To compare the DS structure with that of the EF-hand helix-loop-helix motif, we analyzed the solution secondary structure of the DS from the cellobiohydrolase CelS subunit of the Clostridium thermocellum cellulosome using multidimensional heteronuclear NMR spectroscopy. The effect of Ca(2+)-binding on the DS structure was first investigated by using 2D (15)N-(1)H HSQC NMR spectroscopy. Changes in the spectra during Ca(2+) titration revealed that Ca(2+) induces folding of DS into its tertiary structure. This Ca(2+)-induced protein folding distinguishes DS from typical EF-hand-containing proteins. Sequential backbone assignments were determined for 63 of 69 residues. Analysis of the NOE connectivities and H(alpha) chemical shifts revealed that each half of the dockerin contains just one alpha-helix, comparable to the F-helix of the EF-hand motif. Thus, the structure of the DS Ca(2+)-binding subdomain deviates from that of the canonical EF-hand motif.

[Studies on chemical constituents in the root of Desmos grandifolius (I)]

OBJECTIVE

To investigate new compounds with anti-tumor activities from the root of Desmos grandifolius of Annonaceae.

METHOD

The chemical constituents were isolated by silica gel column chromatography, and the structures were elucidated by UV, IR, MS, 1H NMR, 13C NMR, H-H COSY and NOESY analysis.

RESULTS

Six compounds have been isolated from the CHCl3 extract of this plant and identified as lawinal(I), isolawinal(II), desmethoxymatteucinol(III), benzoic acid(IV), beta-sitosterol(V) and sitgmasterol (VI).

CONCLUSION

All compounds were found from this plant for the first time. Three dihydroflavonoids isolated from this species are characterized by A-ring substitution and no B-ring substitution.

Carbohydrate specificity of an agglutinin isolated from the root of Trichosanthes kirilowii

The root of Trichosanthes kirilowii, which has been used as Chinese folk medicine for more than two thousand years, contains a Gal specific lectin (TKA). In order to elucidate its binding roles, the carbohydrate specificities of TKA were studied by enzyme linked lectinosorbent assay (ELLSA) and by inhibition of lectin-glycoform binding. Among glycoproteins (gp) tested, TKA reacted strongly with complex carbohydrates with Galbeta1-->4GlcNAc clusters as internal or core structures (human blood group ABH active glycoproteins from human ovarian cyst fluids, hog gastric mucin, and fetuin), porcine salivary glycoprotein and its asialo product, but it was inactive with heparin and mannan (negative control). Of the sugar inhibitors tested for inhibition of binding, Neu5Ac alpha2-->3/6Galbeta1-->4Glc was the best and about 4, 14.6 and 27.7 times more active than Galbeta1-->4GlcNAc(II), Galbeta1-->3GalNAc(T) and Gal, respectively. From these results, it is suggested that this agglutinin is specific for terminal or internal polyvalent Galbeta1-->4GlcNAcbeta1-->, terminal Neu5Ac alpha2-->3/6Galbeta1-->4Glc and cluster forms of Galbeta1-->3GalNAc alpha residues. The unusual affinity of TKA for terminal and internal Galbeta1-->glycotopes may be used to explain the possible attachment roles of this agglutinin in this folk medicine to target cells.

DNA polymorphisms at the apolipoprotein A1-CIII loci in Taiwanese: correlation of plasma APOCIII with triglyceride level and body mass index

BACKGROUND AND PURPOSE

Apolipoprotein (APO) A1-CIII genes are linked within a 2.6-kb region on human chromosome 11. ApoA1 is the main component of high-density lipoprotein (HDL), and apoCIII inhibits lipoprotein lipase activity. Genetic variations in APOA1-CIII may affect the function of apoA1/apoCIII and plasma lipid/lipoprotein levels, and thus, the risk of developing atherosclerosis. This study compared the frequency distributions of genetic variations in APOA1-CIII genes and their influence on plasma lipid concentrations in Taiwanese patients with coronary artery disease (CAD) and in healthy controls.

METHODS

Six restriction site variations (RSVs) of the APOA1-CIII gene complex were investigated by DNA amplification using polymerase chain reaction and restriction enzyme digestion in 229 control subjects and 131 CAD patients during the period from 1992 through 1996. The blood lipid profiles of these subjects were also determined.

RESULTS

Thirty-seven distinct six-RSV genotypes were observed. Separate comparisons of the frequency distributions of the six genetic variations showed no significant differences between CAD patients and controls subjects, but the combined six-RSV-genotypes showed different frequency distributions between these two groups. Nine of the 37 six-RSV genotypes were found only in the CAD patients and higher frequencies of two of these types were observed in the CAD patients than in healthy controls. The effects of these genetic variations were on high-density lipoprotein cholesterol in women (for MspIB, PstI, SstI and PvuII RSV) and total cholesterol (for PvuII RSV), low-density lipoprotein cholesterol (for XmnI RSV), and apolipoprotein B (for MspI and SstI RSV) levels in men in the control group. Elevated plasma apoCIII concentration was significantly associated with an increased plasma triglyceride level and body mass index in the control group (P < 0.0001).

CONCLUSIONS

Analysis of the frequency distribution of six RSVs of the APOA1-CIII gene complex in Taiwanese CAD patients and control subjects showed that the effect of genotype on plasma lipid levels was gender-specific and that the apoCIII level was closely associated with plasma triglyceride level and body mass index.

Cyclophosphamides as hypoxia-activated diffusible cytotoxins: a theoretical study

Cyclophosphamides have been in clinical use as anti-cancer drugs for a long time and much research has been directed towards reducing their side effects. Here we have performed a theoretical investigation into the possibility of designing bioreductive analogues of cyclophosphamides. Our calculations have employed semiempirical molecular orbital AM1-SM2 and PM3-SM3 calculations, as implemented in MOPAC 93, which include a modified Born method for the treatment of solvation. We have investigated the effect of bioreductive activation on the beta-elimination reaction that is central to the activation of cyclophosphamides. The approach was tested on two known bioreductive agents, including CB1954, and gave results in agreement with experiment. Non-local density functional calculations on CB1954 and its metabolites, including the radical anion, were in agreement with the semiempirical calculations. The calculations have identified a number of potentially novel bioreductive cyclophosphamides. In particular, our calculations identified compounds in which the initial one-electron reduction was not activating. Such compounds are likely to be more effective bioreductive agents, as the beta-elimination will not compete under oxic conditions with the important re-oxidation required for the protection of oxic tissue.

Cytogenetic pattern of childhood leukemia in Taiwan

BACKGROUND

Cytogenetic analyses of leukemic cells can be used to define specific subgroups of leukemia with different prognoses and, thereby, indicate appropriate treatment for individual cases. In this study, we investigated the cytogenetic pattern of childhood leukemia in Taiwanese patients.

METHODS

A modified trypsin method of Seabright was used for G-banding of metaphase cells.

RESULTS

From October 1996 to January 1999, 111 children with a diagnosis of leukemia were enrolled in the study. Of these, 73 patients had a diagnosis of acute lymphoblastic leukemia (ALL) and 63 of these patients had successful karyotyping of their leukemic cells. Among them, 20 (30.3%) had a normal karyotype, five had hypodiploidy (all had 45 chromosomes), five had low hyperdiploidy (47-50 chromosomes), 16 (24.2%) had high hyperdiploidy (> 50 chromosomes), and 20 had pseudodiploidy. Chromosomal translocation was identified in 24 (36.4%) of the ALL patients, 17 of whom had recurrent translocations including 10 with CD10+ B-precursor ALL [4 with t(9;22), 5 with t(1;19), and 1 infant with t(8;14)(q24;q11)], one neonate with CD10- early pre-B ALL with t(4;11), three B-cell cases with t(8;14), and three T-cell cases [2 with t(11;19)(q23;p13), and 1 (11;14)(p13;q11)]. One B-precursor patient had dic (9;12). Karyotypes of the 30 patients with acute myeloid leukemia (AML) included eight with t(8;21); seven with the French-American-British-M2 subtype (FAB-M2) and one with M1. All four of the patients with M3 had t(15;17), one patient with M4 had inv(16) and 7q-, one with M4Eo (M4 with eosinophilia) had t(7;16)(q21;q22), one with M0 had t(4;11)(q21;q23), and the remaining 11 had a normal karyotype. Three of the five adult-type chronic myeloid leukemia patients had standard Philadelphia chromosome, and the other two had a variant-form of Philadelphia chromosome. Both of the patients with juvenile myelomonocytic leukemia and one patient with myelodysplastic syndrome had a normal karyotype.

CONCLUSIONS

Most findings were similar to previous reports. Although the high proportion of FAB-M2 patients (7/8) with t(8;21) and the consequently higher frequency (26.7%) of this translocation in the 30 AML cases in this study might have significance, a larger series of cases is needed to establish this finding.

Immunobiologic, cytogenetic and drug response features of a newly established cell line (SCRC-1) from renal small cell carcinoma

PURPOSE

We describe the establishment and preliminary characterization of a cell line designated SCRC-1, which was derived from a primary renal small cell carcinoma.

MATERIALS AND METHODS

Continuous cultures of a primary stage IVa renal small cell carcinoma and a xenograft in nude mice derived therefrom were characterized by immunohistology, electron microscopy, immunofluorescence/flow cytometry, cytogenetic analysis, and an in vitro drug resistance assay.

RESULTS

SCRC-1 cells were reactive with antibodies to NSE, chromogranin-A, bombesin, Bcl-2, CD44s, CD44v6, CD44v7 to 8, vimentin and S100 protein (predominantly beta-subunit), and were unreactive with antibodies to EMA, CD54, EGFR(R1), URO-5, URO-7, URO-8 and URO-10. A similar immunoprofile was also found in both the primary tumor and the xenograft. Cytogenetic analysis revealed the following common clonal aberrations in all 50 metaphases analyzed: 45, XX, t (X;10;18) (p11;p11;q11), -der(18)t(X;10;18), indicating the clonal nature of this neoplasm. SCRC-1 cells showed low drug resistance to cyclophosphamide, doxorubicin, gemcitabine and fluorouracil, intermediate resistance to carmustine and mitomycin-C, and extreme resistance to cisplatin.

CONCLUSION

We have documented the initial characterization of SCRC-1, which may be the first cell line reported to be derived from a primary small cell carcinoma of the kidney. This cell line can be used for further studies uncovering the biology and histogenesis of this rare cancer and delineating differences among small cell carcinomas of the kidney and other histological types.

Characterization of Porphyromonas gingivalis-induced degradation of epithelial cell junctional complexes

Porphyromonas gingivalis is considered among the etiological agents of human adult periodontitis. Although in vitro studies have shown that P. gingivalis has the ability to invade epithelial cell lines, its effect on the epithelial barrier junctions is not known. Immunofluorescence analysis of human gingival epithelial cells confirmed the presence of tight-junction (occludin), adherens junction (E-cadherin), and cell-extracellular matrix junction (beta1-integrin) transmembrane proteins. These transmembrane proteins are expressed in Madin-Darby canine kidney (MDCK) cells. In addition, MDCK cells polarize and therefore serve as a useful in vitro model for studies on the epithelial cell barrier. Using the MDCK cell system, we examined the effect of P. gingivalis on epithelial barrier function. Exposure of the basolateral surfaces of MDCK cells to P. gingivalis (>10(9) bacteria/ml) resulted in a decrease in transepithelial resistance. Immunofluorescence microscopy demonstrated decreases in the amounts of immunoreactive occludin, E-cadherin, and beta1-integrin at specific times which were related to a disruption of cell-cell junctions in MDCK cells exposed to basolateral P. gingivalis. Disruption of cell-cell junctions was also observed upon apical exposure to bacteria; however, the effects took longer than those seen upon basolateral exposure. Cell viability was not affected by either basolateral or apical exposure to P. gingivalis. Western blot analysis demonstrated hydrolysis of occludin, E-cadherin, and beta1-integrin in lysates derived from MDCK cells exposed to P. gingivalis. Immunoprecipitated occludin and E-cadherin molecules from MDCK cell lysates were also degraded by P. gingivalis, suggesting a bacterial protease(s) capable of cleaving these epithelial junction transmembrane proteins. Collectively, these data suggest that P. gingivalis is able to invade the deeper structures of connective tissues via a paracellular pathway by degrading epithelial cell-cell junction complexes, thus allowing the spread of the bacterium. These results also indicate the importance of a critical threshold concentration of P. gingivalis to initiate epithelial barrier destruction.

A rational design of bioactive taxanes with side chains situated elsewhere than on C-13

The structure of alphabeta-tubulin was refined and used in the docking study for taxuspine D, paclitaxel and their analogues. The conformational space in the binding site was explored by molecular dynamics. The interaction energy was calculated by minimization in the active site of beta-tubulin. The C-5 cinnamoyl side chain in taxuspine D is found to mimic the C-13 side chain of paclitaxel. A virtual taxane with a new C-5 side chain is predicted to be more active than taxuspine D. The C-13 side chain could be replaced with a novel C-5 side chain if the conformation of the core skeleton is modified.

Forssman pentasaccharide and polyvalent Galbeta1-->4GlcNAc as major ligands with affinity for Caragana arborescens agglutinin

The binding properties of Caragana arborescens agglutinin (CAA, pea tree agglutinin) were studied by enzyme linked lectinosorbent assay (ELLSA) and by inhibition of CAA-glycan interaction. Among glycoproteins (gps) tested, CAA reacted strongly with asialo bird nest gp, asialo rat sublingual gp, human Tamm-Horsfall Sd(a(+)) urinary gp (THGP) and asialo THGP that are rich in GalNAcalpha1-->, GalNAcbeta1--> and/or Galbeta1-->4GlcNAc residues. CAA also bound tightly with multi-valent Galbeta1-->4GlcNAc (mII) containing glycoproteins (human blood group precursor gps, asialo fetuin) and asialo ovine salivary glycoprotein (Tn, GalNAcalpha1-->Ser/Thr), but CAA reacted poorly or not at all with sialylated glycoproteins tested. Of the sugars tested for inhibition of binding, Forssman pentasaccharide (F(p), GalNAcalpha1-->3GalNAcbeta1-->3Galalpha1-->4Galbeta 1-->4Glc) was the best. It was about 2.3, 9.5 and 52.6 times more active than Galbeta1-->4GlcNAc, GalNAc and Gal, respectively, and about 1.9 times more active than tri-antennary Galbeta1-->4GlcNAc (Tri-II). These results suggest that this agglutinin is mainly specific for F(p), mII and Tn clusters. This property can be used to detect human abnormal glycotopes related to F(p) and unmasked mII/Tn clusters and to study cell growth and differentiation given the lack of toxicity of this lectin toward mouse fibroblast cells.