Synthesis and antiviral activity of D- and L-isodideoxy nucleosides with exocyclic-methylene

Novel D- and L-isodideoxynucleosides were synthesized starting from D- and L-xylose and evaluated for antiviral activities against HIV-1, HSV-1, HSV-2, HBV and HCMV, respectively.

Fatal disseminated Trichoderma longibrachiatum infection in an adult bone marrow transplant patient: species identification and review of the literature

Trichoderma longibrachiatum was recovered from stool surveillance cultures and a perirectal ulcer biopsy specimen from a 29-year-old male who had received an allogeneic bone marrow transplant for acute lymphoblastic leukemia. The amphotericin B (2.0 microgram/ml) and itraconazole (1.0 microgram/ml) MICs for the organism were elevated. Therapy with these agents was unsuccessful, and the patient died on day 58 posttransplantation. At autopsy, histologic sections from the lungs, liver, brain, and intestinal wall showed infiltration by branching septate hyphae. Cultures were positive for Trichoderma longibrachiatum. While Trichoderma species have been recognized to be pathogenic in profoundly immunosuppressed hosts with increasing frequency, this is the first report of probable acquisition through the gastrointestinal tract. Salient features regarding the identification of molds in the Trichoderma longibrachiatum species aggregate are presented.

Immunization with recombinant Helicobacter pylori urease decreases colonization levels following experimental infection of rhesus monkeys

Rhesus monkeys, naturally colonized with H. pylori as indicated by culture and histology were immunized with either 40 mg recombinant H. pylori urease administered orally together with 25 microg Escherichia coli heat-labile enterotoxin (LT) or immunized with LT alone. An initial 6 doses were administered over an 8 week period. All five vaccinated monkeys had a greater than two-fold rise in urease-specific serum IgG and IgA level and urease-specific salivary IgA was induced in 3 of 5 vaccinated animals after 6 or 7 doses of vaccine. Vaccination had no measurable therapeutic effect on H. pylori colonization. H. pylori was eradicated from these monkeys with a course of antimicrobials plus omeprazole, a 7th vaccine dose was given (10 months after the 6th dose) and they were rechallenged with H. pylori. Necropsy was performed 23 weeks after rechallenge and H. pylori colonization was determined by histological examination of 12 individual gastric sites. A significant reduction in colonization (p < or = 0.0001; Friedman's analysis of variance) was found in the vaccinated animals. Histopathologic examination of necropsy tissues also revealed a trend towards reduced gastritis and epithelial alterations in the vaccinated group compared to animals receiving LT alone. This study provides the first evidence for effective vaccination of nonhuman primates against H. pylori, and preliminary evidence that a reduction in bacterial density attributable to immunization may lessen gastric inflammation.

Oral immunization with recombinant Helicobacter pylori urease confers long-lasting immunity against Helicobacter felis infection

Recombinant Helicobacter pylori urease (rUre) has been shown to confer protection against challenge with Helicobacter felis in mice. The purpose of the present study was to examine duration of the immune response and long-term protective efficacy of immunization with rUre. Swiss Webster mice were orally immunized four times at weekly intervals with 100 microg rUre plus 5 microg heat-labile enterotoxin of Escherichia coli (LT) adjuvant, or with LT only. At 4, 10, 20 or 40 weeks post immunization, 25 rUre-immunized mice and control mice were challenged with H. felis and sacrificed at 2 or 10 weeks post-challenge. H. felis infection was assessed by gastric urease assay and by histology. Anti-H. pylori urease specific antibody levels were measured in serum and saliva both pre- and post-challenge. Over the 40 week time period, the infection rates in rUre-immunized mice were significantly lower than those in controls (p < 0.05) as assessed by gastric urease activity. Protection ranged from 79 100% at 2 weeks post-challenge and 63-78% at 10 weeks post-challenge. Gastric bacterial density in rUre-immunized mice was significantly lower than that of controls (p < 0.03) as determined by histologic assessment. Anti-urease antibody levels remained elevated in the serum and mucosal compartments at 39 weeks following immunization. This study shows that immunization with rUre plus LT results in long-lasting protective immunity against challenge with H. felis.

Essential role of STAT3 for embryonic stem cell pluripotency

Propagation of mouse embryonic stem (ES) cells in vitro requires exogenous leukemia inhibitory factor (LIF) or related cytokines. Potential downstream effectors of the LIF signal in ES cells include kinases of the Src, Jak, and mitogen-activated protein families and the signal transducer and transcriptional activator STAT3. Activation of nuclear STAT3 and the ability of ES cells to grow as undifferentiated clones were monitored during LIF withdrawal. A correlation was found between levels of STAT3 activity and maintenance of an undifferentiated phenotype at clonal density. In contrast, variation in STAT3 activity did not affect cell proliferation. The requirement for STAT3 was analyzed by targeted mutagenesis in ES cell lines exhibiting different degrees of LIF dependency. An insertional mutation was devised that abrogated Stat3 gene expression but could be reversed by Cre recombination-mediated excision. ES cells heterozygous for the Stat3 mutation could be isolated only from E14 cells, the line least dependent on LIF for self-renewal. Targeted clones isolated from other ES cell lines were invariably trisomic for chromosome 11, which carries the Stat3 locus, and retained normal levels of activated STAT3. Cre-regulated reduction of Stat3 gene copy number in targeted, euploid E14 clones resulted in dose-dependent losses of STAT3 activity and the efficiency of self-renewal without commensurate changes in cell cycle progression. These results demonstrate an essential role for a critical amount of STAT3 in the maintenance of an undifferentiated ES cell phenotype.

Cloning thymic precursor cells: demonstration that individual pro-T1 cells have dual T-NK potential and individual pro-T2 cells have dual alphabeta-gammadelta T cell potential

Thymic progenitors have the capacity to generate alphabeta T cells, gammadelta T cells, and NK cells. To determine whether these three lineages derive from a single precursor cell or from different precursors, a procedure was developed for cloning precursor cells from mouse embryonic thymus. The progeny of each pro-T cell clone were then tested for the potential to generate alphabeta, gammadelta, and NK cells. Of these precursor clones, about half displayed dual potential, developing into either T cells or NK cells, demonstrating the existence of a common T/NK precursor cell in the thymus. The other half of the clones were restricted to T cell development. No precursor clones were restricted to NK development. The common T/NK precursors were shown to be of the pro-T1 (CD25(-)) stage whereas the T-restricted precursors were shown to be of the later pro-T2 (CD25(+)) stage. Both alphabeta and gammadelta T cells were generated from all clones derived from either pro-T1 or -T2 precursors. This shows that commitment of a cell to the alphabeta versus gammadelta lineages does not precede rearrangement of the TCR genes (which occurs immediately after the pro-T2 stage).

The effect of cotinine or cigarette smoke co-administration on the formation of O6-methylguanine adducts in the lung and liver of A/J mice treated with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific nitrosamine, induces lung adenomas in A/J mice, following a single intraperitoneal (i.p.) injection. However, inhalation of tobacco smoke has not induced or promoted tumors in these mice. NNK-induced lung tumorigenesis is thought to involve O6-methylguanine (O6MeG) formation, leading to GC-->AT transitional mispairing and an activation of the K-ras proto-oncogene in the A/J mouse. NNK can be metabolized by several different cytochromes P450, resulting in a number of metabolites. Formation of the promutagenic DNA adduct O6MeG is believed to require metabolic activation of NNK by cytochrome P450-mediated alpha-hydroxylation of the methylene group adjacent to the N-nitroso nitrogen to yield the unstable intermediate, methanediazohydroxide. Nicotine, cotinine (the major metabolite of nicotine), and aqueous cigarette tar extract (ACTE) have all been shown to effectively inhibit metabolic activation of NNK to its mutagenic form, most likely due to competitive inhibition of the cytochrome P450 enzymes involved in alpha-hydroxylation of NNK. The objective of the current study was to monitor the effects of cotinine and cigarette smoke (CS) on the formation of O6MeG in target tissues of mice during the acute phase of NNK treatment. To test the effect of cotinine, mature female A/J mice received a single intraperitoneal injection of NNK (0, 2.5, 5, 7.5, or 10 mumole/mouse) with cotinine administered at a total dose of 50 mumole/mouse in 3 separate i.p. injections, administered 30 min before, immediately after, and 30 min after NNK treatment. To test the effect of whole smoke exposure on NNK-related O6MeG formation, mice were exposed to smoke generated from Kentucky 1R4F reference cigarettes at 0, 0.4, 0.6, or 0.8 mg wet total particulate matter/liter (WTPM/L) for 2 h, with a single i.p. injection of NNK (0, 3.75, or 7.5 mumole/mouse) midway through the exposure. Cigarette smoke alone failed to yield detectable levels of O6MeG. The number of O6MeG adducts following i.p. injection of NNK was significantly (p < 0.05) reduced in both lung and liver by cotinine and by cigarette smoke exposure. Our results demonstrate that NNK-induced O6MeG DNA adducts in A/J mice are significantly reduced when NNK is administered together with either cotinine, the major metabolite of nicotine, or the parental complex mixture, cigarette smoke.

Prevalence of suicide ideation and suicide attempts in nine countries

BACKGROUND

There are few cross-national comparisons of the rates of suicide ideation and attempts across diverse countries. Nine independently conducted epidemiological surveys using similar diagnostic assessment and criteria provided an opportunity to obtain that data.

METHODS

Suicide ideation and attempts were assessed on the Diagnostic Interview Schedule in over 40000 subjects drawn from the United States, Canada, Puerto Rico, France, West Germany, Lebanon, Taiwan, Korea and New Zealand.

RESULTS

The lifetime prevalence rates/100 for suicide ideation ranged from 2.09 (Beirut) to 18.51 (Christchurch, New Zealand). Lifetime prevalence rates/100 for suicide attempts ranged from 0.72 (Beirut) to 5.93 (Puerto Rico). Females as compared to males had only marginally higher rates of suicidal ideation in most countries, reaching a two-fold increase in Taiwan. Females as compared to males had more consistently higher rates for suicide attempts, reaching a two- to three-fold increase in most countries. Suicide ideation and attempts in most countries were associated with being currently divorced/separated as compared to currently married.

CONCLUSIONS

While the rates of suicide ideation varied widely by country, the rates of suicide attempts were more consistent across most countries. The variations were only partly explained by variation in rates of psychiatric disorders, divorce or separation among countries and are probably due to cultural features that we do not, as yet, understand.

Immunization of mice with urease vaccine affords protection against Helicobacter pylori infection in the absence of antibodies and is mediated by MHC class II-restricted responses

We examined the roles of cell- and antibody-mediated immunity in urease vaccine-induced protection against Helicobacter pylori infection. Normal and knockout mice deficient in major histocompatibility complex (MHC) class I, MHC class II, or B cell responses were mucosally immunized with urease plus Escherichia coli heat-labile enterotoxin (LT), or parenterally immunized with urease plus aluminum hydroxide or a glycolipid adjuvant, challenged with H. pylori strain X47-2AL, and H. pylori organisms and leukocyte infiltration in the gastric mucosa quantified. In an adjuvant/route study in normal mice, there was a direct correlation between the level of protection and the density of T cells recruited to the gastric mucosa. In knockout studies, oral immunization with urease plus LT protected MHC class I knockout mice [beta2-microglobulin (-/-)] but not MHC class II knockout mice [I-Ab (-/-)]. In B cell knockout mice [microMT (-/-)], vaccine-induced protection was equivalent to that observed in immunized wild-type (+/+) mice; no IgA+ cells were detected in the stomach, but levels of CD4(+) cells equivalent to those in the wild-type strain (+/+) were seen. These studies indicate that protection of mice against H. pylori infection by immunization with the urease antigen is dependent on MHC class II-restricted, cell-mediated mechanisms, and antibody responses to urease are not required for protection.

Screening and isolation of antibiotic resistance inhibitors from herb materials IV-resistance inhibitors from Anetheum graveolens and Acorus gramineus

The hexane fractions from methanolic extracts of Anetheum graveolens L. (Umbelliferae) and Acorus gramineus Soland. (Araceae), revealed potent inhibitory activities against the resistance of multi-drug resistant Staphylococcus aureus SA2 when combined with ampicillin (Am) or chloramphenicol (Cm). As active principles, carvone and the liquid mixture containing carvone from Anetheum graveolens L. and a liquid mixture mainly consisting of benzoic acid phenylmethyl ester (benzyl benzoate) from Acorus gramineus Soland, were identified. They showed resistance inhibition at the level of 20-50 micrograms/ml when combined with 100 or 50 micrograms/ml of Am or Cm, respectively.

A nationwide epidemiological study of mental disorders in Korea

Epidemiological studies in Korea on mental illness began about four decades ago by Choi and Yoo. This was followed by more than 25 papers. Interviews by psychiatrists were not randomly selected samples. Consistent diagnostic tools were not used except by Yeon et al. The definition of prevalence was not definite and, therefore, not comparable. The research was confined to major psychoses such as schizophrenia, manic depressive illnesses, mental retardation and epilepsy. Most of the studies were performed in rural areas only. The present study was designed to meet the above described criteria as well as testing the applicability of Diagnostic Interview Schedule-III (DIS-III) in Korea. In order to accomplish those goals the Korean version of DIS-III was constructed and the lifetime prevalence of mental disorders was studied both in urban (Seoul) and rural areas.

Clearance of persistent hepatitis B virus infection in Chinese bone marrow transplant recipients whose donors were anti-hepatitis B core- and anti-hepatitis B surface antibody-positive

Thirteen hepatitis B surface antigen-positive Chinese patients who received hepatitis B surface antibody-positive marrow (hepatitis B core antibody-positive or -negative: 6 and 7, respectively) via allogeneic bone marrow transplantation (BMT) were studied. After BMT, 4 recipients had serologic clearance of hepatitis B surface antigen from hepatitis B core antibody-positive marrow, but none of the recipients of hepatitis B core antibody-negative marrow had serologic clearance (P=.02). There was no significant difference in the donors' hepatitis B surface antibody titer before BMT for patients with or without serologic clearance of hepatitis B surface antigen (2255.2+/-4244.0 vs. 854.2+/-2306.7 mIU/mL; P=not significant). Adoptive immunity clearance of hepatitis B surface antigen was favored by hepatitis B core antibody positive-donor marrow and was not related to donor pre-BMT hepatitis B surface antibody titer.

Allogeneic bone marrow transplantation for adult acute lymphoblastic leukemia: a single-centre experience

Between 1990 and 1997, we performed 29 allogeneic BMTs for acute lymphoblastic leukemia (ALL) patients with HLA-identical sibs. Their median age was 31 years (range 15 to 43); there were 15 males and 14 females. The conditioning protocol was Cy-TBI (n = 15), VP16-Cy-TBI(n = 12), CBV (n = 1) and Bu-Cy (n = 1). Cyclosporin and methotrexate were used for GVHD prophylaxis. The median disease-free survival (DFS) was 12 months (range 1 to 92) with an actuarial 4-years DFS of 42.3 per cent. Three patients died of transplant-related complications before 100 days. Relapse occurred in 11 cases at a median time of 5 months (range 3 to 14). All nine patients relapsing within one year died form resistant leukemia. Three patients died of late treatment-related complications. There were 13 survivors (median follow-up 38 months, range 12-98), with 12 in remission. Only four had limited cGVHD, and all had 100 per cent performance scores. One patient also cleared her chronic hepatitis B carrier status due to acquired immunity. The DFS rates amongst CR1 cases and R1/CR2 cases were comparable (p = 0.39). No long-term DFS is obtained from patients with resistant disease (n = 4). The survival results for BMT at CR1 were superior to those using intensive chemotherapy consolidation (p = 0.29), mainly due to poor late results in the chemotherapy arm. For young ALL patients with HLA-matched siblings, the option of BMT should be considered in light of local consolidation survival results.

Purification and characterization of virginiamycin M1 reductase from Streptomyces virginiae

Virginiamycin M1 (VM1), produced by Streptomyces virginiae, is a polyunsaturated macrocyclic lactone antibiotic belonging to the virginiamycin A group. S. virginiae possesses an activity which stereospecifically reduces a 16-carbonyl group of VM1, resulting in antibiotically inactive 16R-dihydroVM1. The corresponding VM1 reductase was purified to homogeneity from crude extracts of S. virginiae in five steps, with 5,650-fold purification and 23% overall yield. The N-terminal amino acid sequence was determined to be MAIKLVIA. The purified enzyme showed an apparent Mr of 73,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an Mr of 280,000 by native molecular sieve high-performance liquid chromatography, indicating the tetrameric nature of the native enzyme. NADPH served as a coenzyme for the reduction, with a Km value of 0.13 mM, but NADH did not support the reaction, even at a concentration of 5 mM, indicating the NADPH-specific nature of the enzyme. The Km for VM1 was determined to be 1.5 mM in the presence of 2 mM NADPH. In the reverse reaction, only 16R-dihydroVM1, not the 16S-epimer, served as a substrate, with a less than 0.1% overall reaction rate compared to that of the forward reaction, confirming that the VM1 reductase participates solely in VM1 inactivation in vivo.

CD16 cross-linking blocks rearrangement of the TCR beta locus and development of alpha beta T cells and induces development of NK cells from thymic progenitors

Mouse thymocytes normally develop into T lymphocytes, but the embryonic thymus also contains precursor cells capable of developing into NK cells. Here, we describe conditions that induce pro-T cells to develop into NK cells. CD16 is expressed on thymic pro-T cells. We observed that CD16 cross-linking during culture of embryonic thymic organs suppressed rearrangement of the TCR beta locus (but did not inhibit TCR gamma locus rearrangement). Rearrangement of the TCR beta locus is normally required for development to the CD4+CD8+, and this development was also suppressed by CD16 cross-linking. The ability of CD16 cross-linking to block alpha beta T cell development was not attributable to toxic effects, but rather was accompanied by promotion of development into NK cells, identified based on molecular and functional criteria. These results suggest that common lymphoid precursors can respond to environmental signals to commit to the alpha beta T vs NK developmental pathways.

The effect of acupuncture on the incidence of postextubation laryngospasm in children

Laryngospasm occurring after tracheal extubation in children is potentially dangerous. This study uses acupuncture with bloodletting at the Shao Shang (L 11) or Shang Yang (Li 1) acupoints to investigate whether this technique can prevent or treat laryngospasm. Seventy-six patients were randomly divided into two groups. Patients in the acupuncture group (n = 38) were treated with bilateral Shao Shang acupunctures at the end of the operation. Patients in the control group (n = 38) were not. The incidence of laryngospasm in the acupuncture group (5.3%) was less than that in the control group (23.7%) (p < 0.05). If laryngospasm developed, patients were immediately treated with acupuncture at either the Shao Shang or Shang Yang acupoints. As judged by an increase in peripheral oxygen saturation, the laryngospasm was relieved within 1 min of acupuncture in all patients. It is concluded that acupuncture with bloodletting at the Shao Shang acupoint may prevent and treat laryngospasm occurring after tracheal extubation in children.

Immunization against natural Helicobacter pylori infection in nonhuman primates

Helicobacter pylori infection is widespread in some breeding groups of a rhesus monkey colony (71% H. pylori positive by 1 year), and the rate of seroconversion is also high. As a result, these groups can be used to test the safety and efficacy of an anti-H. pylori vaccine. Nine-month-old female animals were randomized to receive either 8 mg of recombinant urease (rUre) plus 25 microg of Escherichia coli heat-labile enterotoxin (LT) (n = 26) or placebo plus LT (n = 29), given four times at 1-week intervals followed by a booster 1 month later. Ten months after the start of the immunization, the animals were subjected to endoscopy and biopsy samples were obtained. H. pylori negativity was defined as no H. pylori growth by culture and no H. pylori observed at histology. By this criterion, 2 (7%) of 29 animals receiving placebo and 8 (31%) of 26 immunized animals were H. pylori negative (P < 0.035). In addition, antral gastritis score was significantly less in H. pylori-negative immunized monkeys than in H. pylori-positive animals, whether they were given rUre plus LT or placebo plus LT (P < 0.02 or P < 0.01, respectively). Interestingly, antral gastritis was also significantly less in H. pylori-positive animals given rUre plus LT than in H. pylori-positive animals given placebo plus LT (P < 0.02). However, quantitative cultures did not demonstrate significant differences between the two latter groups. It is concluded that oral administration of rUre vaccine plus LT significantly protects nonhuman primates against H. pylori infection while not causing undesirable side effects.

Takayasu arteritis presented with acute febrile pericardial effusion

We report the clinical and radiographic findings of Takayasu arteritis (TA) presented with acute febrile pericardial effusion. Our case is unique in that acute pericardial effusion developed in the absence of other intracardiac abnormalities as an initial manifestation of TA. While pericardial effusion is infrequently related with TA, TA should be considered as one of causes of acute febrile pericardial effusion in especially young women.

CEOP treatment results and validity of the International Prognostic Index in Chinese patients with aggressive non-Hodgkin's lymphoma

From 1991 to 1997, we have treated 78 newly diagnosed patients with aggressive non-Hodgkin's lymphoma with a modified CHOP regimen in which epirubicin (60 mg/m2) was used in place of doxorubicin (50 mg/m2), i.e. CEOP (cyclophosphamide, epirubicin, vincristine and prednisolone). The median age was 41 years (range: 17 to 67). Sixty-four (82 per cent) had diffuse large cell (Working Formulation category G) histology. The median LDH level was 453 u/l. Thirty-three (42.3 per cent) and 45 (57.7 per cent) had stage I/II and stage III/IV disease, respectively. Fifty-five of 78 (71 per cent) CEOP-treated patients achieved CR, and the projected DFS and OS were both 65 per cent. In an earlier cohort of patients (from 1985-1991) treated with second or third-generation chemotherapy regimens (m-BACOD, MACOP-B, ProMACE-CytaBOM), CR was achieved in 95/123 (77 per cent) patients and the projected DFS and OS were 62 per cent and 55 per cent. There was no significant difference in the clinical characteristics, CR rates (p = 0.26), DFS (p = 0.38) or OS (p = 0.68) between patients who received CEOP or second/third-generation chemotherapy regimens. Of the patients treated with CEOP, 37.9 per cent, 28.8 per cent, 24.2 per cent and 9.1 per cent were in the age-adjusted International Index L, LI, HI and H risk groups, with CR rates of 82 per cent and 57 per cent in the L/LI and HI/H risk groups (p = 0.03). Moreover, patients in the L, LI and HI/H risk groups had significantly different projected DFS (87 per cent, 62 per cent and 39 per cent, p = 0.02) and OS (85 per cent, 80 per cent and 36 per cent, p = 0.006). In conclusion, CEOP is an effective regimen and the age-adjusted International Index is valid for Chinese patients with aggressive NHL.

Clonorchiasis in bone marrow transplant recipients

Among 380 bone marrow transplant (BMT) recipients, five cases (1.3%) of clonorchiasis were observed from 1991 to 1996. Clonorchis sinensis infection was evident in the results of stool examinations performed for screening purposes 7 days before bone marrow transplantation. Salmonella species were isolated concomitantly from the stools of two of the five patients. None of the patients had symptoms due to clonorchiasis. Ultrasonography did not show dilated hepatobiliary ducts, stones, or periportal fibrosis. Fatty liver changes were detected in one patient. All five patients received praziquantel (25 mg/kg po t.i.d. for 1 day) before bone marrow transplantation. Only two patients who underwent allogeneic transplantation had mild venoocclusive disease of the liver with transient hyperbilirubinemia and mildly elevated liver enzyme levels, whereas hyperbilirubinemia or elevated serum alanine aminotransferase levels, related to conditioning toxicity, occurred in two other patients. After treatment with praziquantel, stool examination for all five patients were negative for C. sinensis ova. In addition, Salmonella species were not detected after ciprofloxacin prophylaxis. All five patients survived for > 300 days. Given the availability of effective therapy and in the absence of excessive complications, clonorchiasis is not a contraindication to bone marrow transplantation.

Synthesis and biological activity of 5-hydroxy-4-quinolones and 5-methoxy-4-quinolones as truncated acridones

A series of 5-hydroxy-4-quinolone (3) and 5-methoxy-4-quinolone (4) derivatives were synthesized as truncated acridone analogues and evaluated for antitumor, antiherpes and antituberculosis activities. Among them 5-hydroxy-8-methoxy-quinolone showed potent antitumor activity (IC50 = 17.7 microM for HL60) which was greater than that of acronycine. However, these compounds didn't show any significant antiherpes or antituberculosis activity.