Homocysteine metabolism in pregnancies complicated by neural-tube defects

Folic acid taken around the time of conception can prevent many neural-tube defects. Women with low-normal vitamin B12 values may also be at increased risk. We considered whether homocysteine metabolism via the enzyme methionine synthase, which requires both folate and B12, could be the critical defect in folate-related neural tube defects. Blood was obtained during pregnancies that produced 81 infants with neural-tube defects and 323 normal children. Samples were assayed for homocysteine, methylmalonic acid, plasma folate, red-cell folate, and B12. Mothers of children with neural-tube defects had significantly higher homocysteine values (8.62 [SD 2.8] mumol/L) than did B12-matched controls (7.96 [2.5] mumol/L, p = 0.03). The difference was significant (p = 0.004) in the lower half of the B12 distribution after adjusting for plasma folate. Our study shows that an abnormality in homocysteine metabolism, apparently related to methionine synthase, is present in many women who give birth to children with neural-tube defects. Overcoming this abnormality is likely to be the mechanism by which folic acid prevents neural-tube defects. These findings suggest that the most effective periconceptional prophylaxis to prevent neural-tube defects may require B12 as well as folic acid.

Phenobarbital for febrile seizures--effects on intelligence and on seizure recurrence

Phenobarbital is widely used in the treatment of children with febrile seizures, although there is concern about possible behavioral and cognitive side effects. In 217 children between 8 and 36 months of age who had had at least one febrile seizure and were at heightened risk of further seizures, we compared the intelligence quotients (IQs) of a group randomly assigned to daily doses of phenobarbital (4 to 5 mg per kilogram of body weight per day) with the IQs of a group randomly assigned to placebo. After two years, the mean IQ was 7.03 [corrected] points lower in the group assigned to phenobarbital than in the placebo group (95 percent confidence interval, -11.52 to -2.5, P = 0.0068 [corrected]). Six months later, after the medication had been tapered and discontinued, the mean IQ was 5.2 points lower in the group assigned to phenobarbital (95 percent confidence interval, -10.5 to 0.04, P = 0.052). The proportion of children remaining free of subsequent seizures did not differ significantly between the treatment groups. We conclude that phenobarbital depresses cognitive performance in children treated for febrile seizures and that this disadvantage, which may outlast the administration of the drug by several months, is not offset by the benefit of seizure prevention.

FLOWERING LOCUS T protein may act as the long-distance florigenic signal in the cucurbits

Cucurbita moschata, a cucurbit species responsive to inductive short-day (SD) photoperiods, and Zucchini yellow mosaic virus (ZYMV) were used to test whether long-distance movement of FLOWERING LOCUS T (FT) mRNA or FT is required for floral induction. Ectopic expression of FT by ZYMV was highly effective in mediating floral induction of long-day (LD)-treated plants. Moreover, the infection zone of ZYMV was far removed from floral meristems, suggesting that FT transcripts do not function as the florigenic signal in this system. Heterografting demonstrated efficient transmission of a florigenic signal from flowering Cucurbita maxima stocks to LD-grown C. moschata scions. Real-time RT-PCR performed on phloem sap collected from C. maxima stocks detected no FT transcripts, whereas mass spectrometry of phloem sap proteins revealed the presence of Cm-FTL1 and Cm-FTL2. Importantly, studies on LD- and SD-treated C. moschata plants established that Cmo-FTL1 and Cmo-FTL2 are regulated by photoperiod at the level of movement into the phloem and not by transcription. Finally, mass spectrometry of florally induced heterografted C. moschata scions revealed that C. maxima FT, but not FT mRNA, crossed the graft union in the phloem translocation stream. Collectively, these studies are consistent with FT functioning as a component of the florigenic signaling system in the cucurbits.

Elevated levels of circulating platelet microparticles, VEGF, IL-6 and RANTES in patients with gastric cancer: possible role of a metastasis predictor

The activation of coagulation, angiogenesis and inflammatory cytokines are considered to be related with tumour growth and metastasis. We investigated the plasma levels of platelet microparticles (PMP), vascular endothelial growth factor (VEGF), IL-6, and the chemokine RANTES in patients with gastric cancer (n=109) and in healthy controls (n=29). The plasma levels of PMP, IL-6 and RANTES were significantly higher in the patients than in the healthy controls, and plasma levels of PMP, VEGF, IL-6 and RANTES were significantly higher in patients with stage IV disease than those in patients with stage I or stage II/III. In terms of predicting distant metastasis, the sensitivities of PMP, VEGF, IL-6 and RANTES were 93.3%, 56.7%, 70.0% and 81.8%, respectively, and the corresponding specificities were 91.1%, 64.6%, 79.7% and 50.0%. Among these parameters, PMP had the highest diagnostic accuracy. Significant correlations were found between PMP, VEGF, IL-6 and RANTES. This study demonstrates that the plasma levels of PMP, VEGF, IL-6 and RANTES were markedly increased in patients with stage IV disease, and that these increased plasma levels of IL-6, RANTES, and especially PMP, might be useful for identifying metastatic gastric patients.

Glucose deprivation-induced oxidative stress in human tumor cells. A fundamental defect in metabolism?

Recently, glucose deprivation-induced oxidative stress has been shown to cause cytotoxicity, activation of signal transduction (i.e., ERK1, ERK2, JNK, and Lyn kinase), and increased expression of genes associated with malignancy (i.e., bFGF and c-Myc) in MCF-7/ADR human breast cancer cells. These results have led to the proposal that intracellular oxidation/reduction reactions involving hydroperoxides and thiols may provide a mechanistic link between metabolism, signal transduction, and gene expression in these human tumor cells. The current study shows that several other transformed human cell types appear to be more susceptible to glucose deprivation-induced cytotoxicity and oxidative stress than untransformed human cell types. In a matched pair of normal and SV40-transformed human fibroblasts the cytotoxic process is shown to be dependent upon ambient O2 concentration. A theoretical model to explain the results is presented and implications to unifying modern theories of cancer are discussed.

Prognostic implications of type and density of tumour-infiltrating lymphocytes in gastric cancer

The study aims to determine whether type and density of tumour-infiltrating lymphocytes (TILs) can predict the clinical course in gastric cancer. Gastric carcinomas (n=220) were immunostained for CD3, CD8, CD20, and CD45RO and evaluated for clinicopathologic characteristics. Number of TILs that immunostained positively for each marker were counted using NIH ImageJ software. Tumours were grouped into low- and high-density groups for each marker (CD3, CD8, CD45RO). The densities of CD3(+), CD8(+), and CD45RO(+) TILs were found to be independent predictors of lymph node metastasis by multivariate analysis with odds ratios (95% CI) of 0.425 (0.204-0.885), 0.325 (0.150-0.707), and 0.402 (0.190-0.850), respectively. Kaplan-Meier survival analysis revealed that patients in the high-density groups for CD3, CD8, and C45RO had a significantly longer survival time than the patients in the corresponding low-density groups, respectively. In multivariate survival analysis, the densities of CD3(+), CD8(+), and CD45RO(+) TILs remained independent prognostic factors with hazard ratios (95% CI) of 0.549 (0.317-0.951), 0.574 (0.347-0.949), and 0.507 (0.298-0.862), respectively. In conclusion, density of TILs was found to be independently predictive of regional lymph node metastasis and patient survival in gastric cancer.

Minimum effective dose of folic acid for food fortification to prevent neural-tube defects

BACKGROUND

Although a daily supplement of 400 micrograms folic acid has been shown to prevent neural-tube defects (NTD), most women do not take the recommended supplement. Thus, food fortification is to be introduced in the USA and is being considered in the UK. Because of safety concerns, the USA has chosen a level of fortification that will increase the average woman's intake by only 100 micrograms. Such an increase, although safe, may be ineffective; but a trial to assess its efficacy would be unethical. Because women with red-cell folate concentrations above 400 micrograms/L have a very low risk of NTD, we undertook a randomised trial of several folic acid doses to find out how much is needed to reach this protective concentration.

METHODS

We screened 323 women. 172 with red-cell folate between 150 micrograms/L and 400 micrograms/L were invited to take part in the trial. 121 women were randomly assigned placebo or 100 micrograms, 200 micrograms, or 400 micrograms daily of additional folic acid. Compliance was monitored by having the women sign a dated sheet when taking the tablet. 95 women completed the 6-month study.

FINDINGS

There were significant increases in red-cell folate in all folic acid groups. The placebo group showed no significant change. The median incremental changes and median post-treatment concentrations were 67 micrograms/L (95% CI 43-120) and 375 micrograms/L (354-444) in the 100 micrograms/day group, 130 micrograms/L (108-184) and 475 micrograms/L (432-503) in the 200 micrograms/day group, and 200 micrograms/L (125-312) and 571 micrograms/L (481-654) in the 400 micrograms/day group.

INTERPRETATION

A fortification programme that delivered 400 micrograms folic acid daily to women would protect against NTD, but at the expense of unnecessarily high exposure for many people. Delivery of 200 micrograms daily is also effective against NTD and safer for the general population. Based on projections from the positive folate balance in the group that received 100 micrograms daily, this dose taken continually, as it will be in fortified food, will also produce an important decrease in NTD.

Oxidative stress inhibits apoptosis in human lymphoma cells

Apoptosis and necrosis are two forms of cell death that are induced under different conditions and that differ in morphological and biochemical features. In this report, we show that, in the presence of oxidative stress, human B lymphoma cells are unable to undergo apoptosis and die instead by a form of necrosis. This was established using the chemotherapy drug VP-16 or the calcium ionophore A23187 to induce apoptosis in Burkitt's lymphoma cell lines and by measuring classical markers of apoptotic death, including cell morphology, annexin V binding, DNA ladder formation, and caspase activation. In the presence of relatively low levels of H2O2 (75-100 microM), VP-16 and A23187 were unable to induce apoptosis in these cells. Instead, the cells underwent non-apoptotic cell death with mild cytoplasmic swelling and nuclear shrinkage, similar to the death observed when they were treated with H2O2 alone. We found that H2O2 inhibits apoptosis by depleting the cells of ATP. The effects of H2O2 can be overcome by inhibitors of poly(ADP)-ribosylation, which also preserve cellular ATP levels, and can be mimicked by agents such as oligomycin, which inhibit ATP synthesis. The results show that oxidants can manipulate cell death pathways, diverting the cell away from apoptosis. The potential physiological ramifications of this finding will be discussed.

Elevated platelet microparticles in transient ischemic attacks, lacunar infarcts, and multiinfarct dementias

Platelets release microparticles (PMP) upon activation. Elevated levels of PMP were observed in patients with immune thrombocytopenic purpura (ITP), sometimes associated with a syndrome resembling transient ischemic attack (TIA), suggesting a thrombogenic potential for PMP. To determine if this association applies to TIA and other cerebrovascular accidents (CVA) without ITP, we studied PMP profiles in 71 patients with ischemic CVA: 28 with small vessel CVA (SCVA), either lacunar infarcts or TIA; 24 with large vessel CVA (LCVA); 19 with multiinfarct dementia (MID); 12 with Alzheimer's dementia (AD); and 31 healthy controls. The mean PMP values were: MID = 3.71 +/- 0.51; SCVA = 3.48 +/- 0.63; LCVA = 1.97 +/- 0.28; AD = 1.19 +/- 0.27; controls = 0.88 +/- 0.09, (all units x 10(7)/mL). PMP values in all groups except AD were significantly above normal (p < 0.01). However, the elevation in SCVA was more marked than in LCVA (p < 0.01). Administration of the calcium channel blocker, nifedipine, to 11 TIA patients reduced PMP significantly.

Urachal remnant diseases: spectrum of CT and US findings

Computed tomography (CT) and ultrasonography (US) are ideally suited for demonstrating urachal remnant diseases. A patent urachus is demonstrated at longitudinal US and occasionally at CT as a tubular connection between the anterosuperior aspect of the bladder and the umbilicus. An umbilical-urachal sinus manifests at US as a thickened tubular structure along the midline below the umbilicus. A vesicourachal diverticulum is usually discovered incidentally at axial CT, appearing as a midline cystic lesion just above the anterosuperior aspect of the bladder. At US, it manifests as an extraluminally protruding, fluid-filled sac that does not communicate with the umbilicus. Urachal cysts manifest at both modalities as a noncommunicating, fluid-filled cavity in the midline lower abdominal wall located just beneath the umbilicus or above the bladder. Both infected urachal cysts and urachal carcinomas commonly display increased echogenicity at US and thick-walled cystic or mixed attenuation at CT, making it difficult to differentiate between them. Percutaneous needle biopsy or fluid aspiration is usually needed for diagnosis and therapeutic planning. Nevertheless, CT and US can help identify most disease entities originating from the urachal remnant in the anterior abdominal wall. Understanding the anatomy and the imaging features of urachal remnant diseases is essential for correct diagnosis and proper management.

Glucose deprivation-induced cytotoxicity and alterations in mitogen-activated protein kinase activation are mediated by oxidative stress in multidrug-resistant human breast carcinoma cells

We previously observed that glucose deprivation induces cell death in multidrug-resistant human breast carcinoma cells (MCF-7/ADR). As a follow up we wished to test the hypothesis that metabolic oxidative stress was the causative process or at least the link between causative processes behind the cytotoxicity. In the studies described here, we demonstrate that mitogen-activated protein kinase (MAPK) was activated within 3 min of being in glucose-free medium and remained activated for 3 h. Glucose deprivation for 2-4 h also caused oxidative stress as evidenced by a 3-fold greater steady state concentration of oxidized glutathione and a 3-fold increase in pro-oxidant production. Glucose and glutamate treatment rapidly suppressed MAPK activation and rescued cells from cytotoxicity. Glutamate and the peroxide scavenger, pyruvate, rescued the cells from cell killing as well as suppressed pro-oxidant production. In addition the thiol antioxidant, N-acetyl-L-cysteine, rescued cells from glucose deprivation-induced cytotoxicity and suppressed MAPK activation. These results suggest that glucose deprivation-induced cytotoxicity and alterations in MAPK signal transduction are mediated by oxidative stress in MCF-7/ADR. These results also support the speculation that a common mechanism of glucose deprivation-induced cytotoxicity in mammalian cells may involve metabolic oxidative stress.

Synthesis of Si, Mg substituted hydroxyapatites and their sintering behaviors

Si, Mg-substituted hydroxyapatites, alone and co-substituted, have been prepared to obtain biomaterials having an improved biocompatibility. From FT-IR, XRD and ICP analyses, it was confirmed that single phases of hydroxyapatite substituted by Si alone or co-substituted by Si, Mg. The XRD data indicated the absence of extra phases related to silicon and magnesium oxide or other calcium phosphate species. Si-substituted hydroxyapatite of up to 2 wt% for Si and Si, Mg co-substituted hydroxyapatite of 1 wt% for the each ion keep their original structures intact for the sintering temperatures of up to 1200 degrees C. However, it is observed that ion substitutions by an amount higher than the above ratios for each hydroxyapatite lead to destabilization of original structures of the hydroxyapatite and to the production of tricalcium phosphate and calcium phosphate silicate phases when the samples were sintered at 1100 degrees C or higher.

Analysis of clinical trials by treatment actually received: is it really an option?

The primary analysis of a randomized clinical trial should compare patients in their randomly assigned treatment groups (intention to treat analysis). When a substantial number of subjects fail to take a prescribed medication or are switched to a different study medication, it is tempting to consider treatment comparisons using only those subjects with treatment as actually received rather than as prescribed. There are several arguments against this approach: the prognostic balance brought about by randomization is likely to be disturbed; sample size will be reduced; and the validity of the statistical test procedures will be undermined. Further, results of analysis by treatment actually received may suffer from a bias introduced by using compliance, a factor often related to outcome independently of the treatment received, to determine the groups for comparison. The extent and nature of this bias will be related to the definition of compliance in an as treated analysis, a definition which could be unintentionally self-serving. We have investigated the problem of the definition of actual treatment in the context of a recent clinical trial. We used several definitions to classify patients as having received or not received treatment as prescribed. These definitions, when used in as treated analyses, provided results that were at times inconsistent or counter-intuitive, and which neither helped to confirm nor further explain the intention to treat analysis.

Extracellular matrix regulates apoptosis in mammary epithelium through a control on insulin signaling

Adherent epithelial cells require interactions with the extracellular matrix for their survival, though the mechanism is ill-defined. In long term cultures of primary mammary epithelial cells, a laminin-rich basement membrane (BM) but not collagen I suppresses apoptosis, indicating that adhesion survival signals are specific in their response (. J. Cell Sci. 109:631-642). We now demonstrate that the signal from BM is mediated by integrins and requires both the alpha6 and beta1 subunits. In addition, a hormonal signal from insulin or insulin-like growth factors, but not hydrocortisone or prolactin, is necessary to suppress mammary cell apoptosis, indicating that BM and soluble factors cooperate in survival signaling. Insulin induced autophosphorylation of its receptor whether mammary cells were cultured on collagen I or BM substrata. However, both the tyrosine phosphorylation of insulin receptor substrate-1 and its association with phosphatidylinositol 3-kinase were enhanced in cells cultured on BM, as was the phosphorylation of the phosphatidylinositol 3-kinase effector, protein kinase B. These results suggest a novel extracellular matrix-dependent restriction point in insulin signaling in mammary epithelial cells. The proximal signal transduction event of insulin receptor phosphorylation is not dependent on extracellular matrix, but the activation of downstream effectors requires adhesion to BM. Since phosphatidylinositol 3-kinase was required for mammary epithelial cell survival, we propose that a possible mechanism for BM-mediated suppression of apoptosis is through its facilitative effects on insulin signaling.

Analysis of the pumpkin phloem proteome provides insights into angiosperm sieve tube function

Increasing evidence suggests that proteins present in the angiosperm sieve tube system play an important role in the long distance signaling system of plants. To identify the nature of these putatively non-cell-autonomous proteins, we adopted a large scale proteomics approach to analyze pumpkin phloem exudates. Phloem proteins were fractionated by fast protein liquid chromatography using both anion and cation exchange columns and then either in-solution or in-gel digested following further separation by SDS-PAGE. A total of 345 LC-MS/MS data sets were analyzed using a combination of Mascot and X!Tandem against the NCBI non-redundant green plant database and an extensive Cucurbit maxima expressed sequence tag database. In this analysis, 1,209 different consensi were obtained of which 1,121 could be annotated from GenBank and BLAST search analyses against three plant species, Arabidopsis thaliana, rice (Oryza sativa), and poplar (Populus trichocarpa). Gene ontology (GO) enrichment analyses identified sets of phloem proteins that function in RNA binding, mRNA translation, ubiquitin-mediated proteolysis, and macromolecular and vesicle trafficking. Our findings indicate that protein synthesis and turnover, processes that were thought to be absent in enucleate sieve elements, likely occur within the angiosperm phloem translocation stream. In addition, our GO analysis identified a set of phloem proteins that are associated with the GO term "embryonic development ending in seed dormancy"; this finding raises the intriguing question as to whether the phloem may exert some level of control over seed development. The universal significance of the phloem proteome was highlighted by conservation of the phloem proteome in species as diverse as monocots (rice), eudicots (Arabidopsis and pumpkin), and trees (poplar). These results are discussed from the perspective of the role played by the phloem proteome as an integral component of the whole plant communication system.

Tandem repeat of a transcriptional enhancer upstream of the sterol 14alpha-demethylase gene (CYP51) in Penicillium digitatum

We investigated the mechanism of resistance to demethylation inhibitors (DMI) in Penicillium digitatum by isolating the CYP51 gene, which encodes the target enzyme (P450(14DM)) of DMI, from three DMI-resistant and three DMI-sensitive strains. The structural genes of all six strains were identical, but in the promoter region, a unique 126-bp sequence was tandemly repeated five times in the DMI-resistant strains and was present only once in the DMI-sensitive strains. Constitutive expression of CYP51 in the resistant strains was about 100-fold higher than that in the sensitive strains. We introduced CYP51, including the promoter region, from a DMI-resistant strain into a DMI-sensitive strain, which rendered the transformants DMI resistant and increased CYP51 expression. We also found that if the number of copies of the repeat was reduced to two, resistance and CYP51 expression also decreased. These results indicate that the 126-bp unit acts as a transcriptional enhancer and that a tandem repeat of the unit enhances CYP51 expression, resulting in DMI resistance. This is a new fungicide resistance mechanism for filamentous fungi.

Ginsenoside-Rg1, one of the major active molecules from Panax ginseng, is a functional ligand of glucocorticoid receptor

We have examined the possibility that a component of Panax ginseng, ginsenoside-Rg1 (G-Rg1), acts by binding to the glucocorticoid receptor (GR). G-Rg1 competed for [3H]dexamethasone (Dex) binding to GR with a specific affinity of 1-10 microM and activated a glucocorticoid responsive element-containing luciferase reporter gene. The dose-dependence patterns of G-Rg1 and Dex for these two effects were nearly identical, although two to three orders of magnitude higher concentration of G-Rg1 than that of Dex was required for the same magnitude of response. At the cellular level, the growth of FT02B cells was suppressed by G-Rg1 as well as by Dex, each of whose effects were abolished by RU486. These results demonstrate that G-Rg1 is a functional ligand of GR.

Osteoclastogenesis is enhanced by activated B cells but suppressed by activated CD8(+) T cells

Host immune response is known to contribute to the progression of periodontitis, and alveolar bone destruction in periodontitis is associated with enhanced osteoclast activity. Therefore, we evaluated the roles of activated lymphocyte subsets in osteoclastogenesis. Osteoclast precursors were co-cultured with activated lymphocytes (B, CD4(+) T, CD8(+) T) in the presence of either macrophage colony-stimulating factor (M-CSF) alone or M-CSF plus soluble receptor activator of NF-kappaB ligand (sRANKL), and subsequent differentiation into active osteoclasts was evaluated by a resorption assay. The activated B and CD4(+) cells, but not CD8(+) T cells, induced osteoclast differentiation in the presence of M-CSF alone. In the presence of M-CSF and sRANKL, B cells induced the formation of small but highly active osteoclasts and increased resorption, while CD8(+) T cells profoundly suppressed osteoclastogenesis. Co-culture using an insert well or supernatant suggested that both B and CD8(+) T cells acted on osteoclasts mostly via soluble proteins. Activated B cells expressed many osteoclastogenic factors including RANKL, TNF-alpha, IL-6, MIP-1alpha, and MCP-3. CD8(+) T cells expressed a substantial amount of osteoprotegerin (OPG) along with RANKL. However, blocking antibody to OPG did not reverse the suppression by CD8(+) T cells, suggesting that other factor(s) are involved. Taken together, activated B cells promoted osteoclastogenesis, while CD8(+) T cells inhibited the osteoclast formation via direct interaction. The results imply the importance of lymphocyte subpopulations in the development of periodontitis.

Analysis of colonoscopic findings in the differential diagnosis between intestinal tuberculosis and Crohn's disease

BACKGROUND AND STUDY AIMS

Intestinal tuberculosis and Crohn's disease are chronic inflammatory bowel disorders that are difficult to differentiate from one another. This study aimed to evaluate the diagnostic value of various colonoscopic findings in the differential diagnosis between intestinal tuberculosis and Crohn's disease.

PATIENTS AND METHODS

Colonoscopic findings on initial work-up were prospectively recorded in patients with an initial diagnosis of either intestinal tuberculosis or Crohn's disease. These findings were analyzed after a final diagnosis of intestinal tuberculosis (n = 44) or Crohn's disease (n = 44) had been made after follow-up.

RESULTS

Four parameters (anorectal lesions, longitudinal ulcers, aphthous ulcers, and cobblestone appearance) were significantly more common in patients with Crohn's disease than in patients with intestinal tuberculosis. Four other parameters (involvement of fewer than four segments, a patulous ileocecal valve, transverse ulcers, and scars or pseudopolyps) were observed more frequently in patients with intestinal tuberculosis than in patients with Crohn's disease. We hypothesized that a diagnosis of Crohn's disease could be made when the number of parameters characteristic of Crohn's disease was higher than the number of parameters characteristic of intestinal tuberculosis, and vice versa. Making these assumptions, we calculated that the diagnosis of either intestinal tuberculosis or Crohn's disease would have been made made correctly in 77 of our 88 patients (87.5 %), incorrectly in seven patients (8.0 %), and would not have been made in four patients (4.5 %).

CONCLUSIONS

A systematic analysis of colonoscopic findings is very useful in the differential diagnosis between intestinal tuberculosis and Crohn's disease.

2-(Hydroxycarbonyl)benzyl glycosides: a novel type of glycosyl donors for highly efficient beta-mannopyranosylation and oligosaccharide synthesis by latent-active glycosylation

2-(Benzyloxycarbonyl)benzyl (BCB) glycosides were prepared by coupling of the corresponding tetraacetylglycosyl bromides and benzyl 2-(hydroxymethyl)benzoate. The BCB glycosides were converted almost quantitatively into the corresponding 2-(hydroxycarbonyl)benzyl (HCB) glycosides by selective hydrogenolysis of the benzyl ester functionality without affecting the benzylidene acetal and the benzyl ether. Treatment of the HCB 4,6-O-benzylidenemannopyranoside 4 with triflic anhydride in the presence of di-tert-butylmethylpyridine and subsequent addition of the glycosyl acceptor having a primary hydroxyl group afforded exclusively the disaccharide of the beta-mannopyranosyl linkage. Glycosylation of the compound 4 with secondary and tertiary alcohols also provided beta-mannopyranosides as the major products. Glycosylation of the HCB 4,6-O-cyclohexylidenemannoside 5 with primary alcohols was also highly beta-selective, and the HCB 2,3-O-cyclohexylidenemannoside 6 exhibited the moderate beta-selectivity. On the other hand, unlike the HCB mannosides, the HCB 4,6-O-benzylideneglucoside 7 gave exclusively the disaccharides of the alpha-glycopyranosyl linkage in the glycosylation with primary alcohols. The latent BCB-disaccharide 23, which was obtained from the HCB mannoside 4 as the donor and the BCB glucoside 12 as the acceptor by the present glycosylation method, was converted into the active HCB-disaccharide 39 by selective hydrogenolysis. Repetitive glycosylation of the donor 39 with the same acceptor 12 afforded the BCB-trisaccharide 40. Other BCB-trisaccharides 42 and 46 were also efficiently synthesized by employing the present methodology.

The -238 tumor necrosis factor-alpha promoter polymorphism is associated with decreased susceptibility to cancers

We investigated the potential association of tumor necrosis factor-alpha (TNF-alpha) promoter polymorphisms with cancers. The study included 169 patients with gastric cancer, uterine cervical cancer, colorectal cancer, or renal cell carcinoma and 92 healthy controls. The -308 and -238 polymorphisms in the TNF-alpha promoter were analyzed by PCR-restriction fragment length polymorphism (RFLP). The proportion of individuals carrying the TNF-238A allele was significantly lower in the cancer group than in the control group. The odds ratio for cancer in subjects with the TNF-238A allele was 0.25 (95% CI, 0.10-0.64). No association was found between the -308 polymorphism and cancers. These results suggest that the -238A allele has a protective function against cancers.

Identification of a signal that distinguishes between the chloroplast outer envelope membrane and the endomembrane system in vivo

Certain small outer envelope membrane proteins of chloroplasts are encoded by the nuclear genome without a cleavable N-terminal transit peptide. We investigated in vivo the targeting mechanism of AtOEP7, an Arabidopsis homolog of the small outer envelope membrane protein. AtOEP7 was expressed as a fusion protein with the green fluorescent protein (GFP) either transiently in protoplasts or stably in transgenic plants. In either case, fluorescence microscopy of transformed cells and protein gel blot analysis of fractionated proteins confirmed that the AtOEP7:GFP fusion protein was targeted to the chloroplast outer envelope membrane. In vivo targeting experiments revealed that two regions, the transmembrane domain (TMD) and its C-terminal neighboring seven-amino acid region, were necessary and sufficient for targeting to the chloroplast outer membrane. Substitution of aspartic acid or lysine residues with glycine residues or scrambling of the amino acid sequence of the seven-amino acid region caused mistargeting to the plasma membrane. Although the amino acid sequence of the TMD is not important for targeting, amino acid residues with large side chains inhibited targeting to the chloroplasts and resulted in the formation of large aggregates in the protoplasts. In addition, introduction of a proline residue within the TMD resulted in inhibition of targeting. Finally, a fusion protein, AtOEP7:NLS:GFP, was targeted efficiently to the chloroplast envelope membranes despite the presence of a nuclear localization signal. On the basis of these results, we conclude that the seven-amino acid region and the TMD are determinants for targeting to the chloroplast outer envelope membrane. The seven-amino acid region plays a critical role in AtOEP7 evading the endomembrane system and entering the chloroplast pathway, and the TMD plays critical roles in migration to the chloroplasts and/or subsequent insertion into the membrane.

dgq: a drosophila gene encoding a visual system-specific G alpha molecule

We describe the isolation and preliminary characterization of a new G alpha gene (dgq) in Drosophila. The dgq gene is differentially spliced, yielding two putative proteins, both of which contain guanine nucleotide binding and hydrolysis domains and share 50% identity with transducins and other G proteins. These proteins represent a new class of G alpha subunits because they lack both high amino acid identity with other G alpha proteins and the pertussis toxin ADP ribosylation site. The dgq mRNA is detected by RNA-RNA Northern hybridization in wild-type heads but not in wild-type bodies or in the mutant eyes absent heads. Tissue in situ hybridization detects dgq expression only in the retina and ocellus of the adult head, making it a prime candidate for encoding the Drosophila transducin analog, the G protein required for phototransduction.

One hundred and eleven liver resections for hilar bile duct cancer

A positive correlation between absence of residual tumor at resection margins and long-term survival in the treatment of hilar bile duct carcinoma has encouraged some surgeons to use a more radical approach, including liver/portal vein resection and combined pancreatoduodenectomy. However, if liver resection is associated with significant morbidity and mortality, it may not produce any overall benefit. This review was undertaken in an attempt to determine whether liver resection is a safe procedure and whether if has any beneficial effect over that of local bile duct excision alone, in terms of achieving curative resection and long-term survival. The records of 151 patients with hilar bile duct carcinoma surgically treated between June 1989 and December 1997 at the Asan Medical Center, Seoul, were retrospectively analyzed. Surgical resection was possible in 128 patients. The remaining 23 patients had surgical palliative drainage. Local bile duct excision alone was performed in 17 patients. Liver resection for tumor extending to secondary bile ducts or hepatic parenchyma was performed in 111 patients; portal vein resection was necessary in 29 of these 111 patients (26.1%) and pancreatoduodenectomy was combined in 18 patients (16.2%). Seven patients died during hospitalization after liver resection, an operative mortality of 6.3%. Margins of bile duct resection were free of tumor on histologic examination in 4 of the 17 local bile duct excisions, but in 86 of the 111 liver resections. The cumulative survival rate after local bile duct excision was 85.7% at 1 year, 42.9% at 2 years, 21.4% at 3 years, and 0% at 4 years. However, the survival rate after liver resection (excluding operative mortality) was 97.1% at 1 year, 72.8% at 2 years, 55.3% at 3 years, and 24.0% at 5 years. Survival and the percentage of patients with tumor-free resection margins after liver resection were superior to those after local bile duct excision. Resection of hilar bile duct carcinoma offers long-term survival only when surgery is aggressive and includes liver resection.