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Effect of lipophilic vitamins on the erythrocyte membrane. 31P NMR and fluorescence studies.

Structural changes induced by the fat-soluble vitamins A, D3, E and K1 in natural membranes were studied by 31P NMR and fluorescence anisotropy on erythrocyte ghosts; the occurrence of cell fusion following vitamin addition was detected by optical microscopy of intact cells. Vitamins A, E and K1, which produce cell fusion, also induce the formation of configurational phases other than the bilayer and increase, at a different extent for the different vitamins, membrane fluidity. Vitamin D3, on the contrary, induces aggregation without fusion, paralleled by bilayer phase stabilization and microviscosity increase. A correlation between fusion phenomena and structural variations in the bilayer organization is therefore suggested.

Animals↗

Characterization of vesicles, containing an acylated oligopeptide, released by human colon adenocarcinoma cells. NMR and biochemical studies.

RNA-containing vesicles, recovered from the supernatant of high-density cell samples of human colon carcinoma, produce a high-resolution 1H NMR spectrum of lipids characterized by isotropic tumbling; these vesicles contain large amounts of triglycerides and cholesterol esters. Both findings have strict analogies to what is displayed by the proteolipid complexes isolated from the sera of tumor-bearing patients [(1985) Proc. Natl. Acad. Sci. USA 82, 3455-3459; (1986) FEBS Lett. 203, 164-168]. Lipid analysis and enzymatic tests indicate that these vesicles are selected micromaps of plasma membranes, analogous to those that can be recovered from culture media in which tumor cells are grown [(1985) Dev. Biol. 3, 33-57]. Peculiar lipids, an acylated oligopeptide and a modified phospholipid, are also present in the vesicles.

Acylation↗

Interaction of HIV-1 with susceptible lymphoblastoid cells. 1H NMR studies.

Different strains of HIV susceptible lymphoblastoid cells have been infected by HIV-1 and examined by means of 1H NMR spectroscopy at different times after infection, taking advantage of the presence of high resolution lipid signals from the plasma membrane of tumor cells. A transient decrease in intensity of fatty acid signals, originated by changes in membrane structure, has been observed early after viral infection. Marked alterations in membrane-dependent steps of phospholipid synthesis can also be inferred by the observed transient depression in peaks from choline-based metabolites. Spectral modifications deriving from changes in lipid metabolism are also produced both in infected cells a few days after infection and in permanently infected cells. 1H NMR can, therefore, monitor structural and metabolic effects induced by HIV infection.

Cell Membrane↗

Effect of omega-3 fatty acids on rectal mucosal cell proliferation in subjects at risk for colon cancer.

The effects of 12 weeks of omega-3 fatty acid supplementation on rectal mucosal proliferation were assessed with [3H]thymidine autoradiography in a double-blind, placebo-controlled study of 20 patients with sporadic adenomatous colorectal polyps. In the group of 10 that received fish oil containing eicosapentaenoic acid (4.1 g/day) and docosahexaenoic acid (3.6 g/day), the mean percentage of replicative "S"-phase cells in the upper part of colonic crypts (considered a reliable marker of colon cancer risk) significantly dropped from the baseline level after only 2 weeks of treatment and remained lower throughout the study period; no change in upper-crypt labeling was observed in the 10 placebo patients. Rectal mucosal eicosapentaenoic acid content increased in fish oil patients, whereas arachidonic acid levels decreased. The fish oil-induced kinetic changes represent contraction of the proliferative compartment to the levels of a low-risk population and may be related to omega-3 fatty acid effects on the arachidonic prostaglandin pathway. In this short-term trial, fish oil appeared to exert a rapid effect that may protect high-risk subjects from colon cancer.

Autoradiography↗

Effects of different doses of fish oil on rectal cell proliferation in patients with sporadic colonic adenomas.

BACKGROUND/AIMS: Fish oil supplementation can reduce cytokinetic anomalies in the flat rectal mucosa of patients with sporadic colorectal adenoma. This study attempted to identify an optimum dose for fish oil supplementation and evaluate the persistence of its effects during long-term administration. METHODS: In a double-blind study, 60 patients with sporadic adenomas received 2.5, 5.1, or 7.7 g of fish oil per day or placebo for 30 days. [3H]thymidine autoradiographic labeling indices were calculated in flat rectal mucosal biopsy specimens collected before and after supplementation. In a subsequent study, 15 patients with polyps received 2.5 g of fish oil per day. Proliferative parameters, mucosal fatty acids, and mucosal and plasma alpha-tocopherol levels were evaluated before, during, and after 6 months of supplementation. RESULTS: Mean proliferative indices and mucosal arachidonic acid levels decreased significantly (and to similar degrees) in all treated groups, whereas mucosal eicosapentaenoic and docosahexaenoic acid levels increased. Significantly reduced proliferation was observed only in patients with abnormal baseline patterns. These effects persisted during long-term, low-dose treatment. A transient reduction in mucosal (but not plasma) alpha-tocopherol levels was observed after 1 month of treatment. Side effects were insignificant. CONCLUSIONS: Low-dose fish oil supplementation has short-term and long-term normalizing effects on the abnormal rectal proliferation patterns associated with increased colon cancer risk.

Adenomatous Polyposis Coli↗

Suppression of acute and relapsing experimental allergic encephalomyelitis with mitoxantrone.

The effect of treatment with the antineoplastic, immunomodulatory agent mitoxantrone on the course of acute and relapsing experimental allergic encephalomyelitis (EAE) in the mouse has been studied. Untreated mice immunized to produce acute EAE had an 81% incidence of clinical disease and 100% incidence of pathologic disease. Mice treated with mitoxantrone at a dose of 0.5 mg/kg daily for the 10 days following immunization did not develop any clinical signs and had minimal pathologic signs of disease. A dose of 0.25 mg/kg gave an intermediate response. Untreated mice immunized for relapsing EAE had a 100% incidence of disease with an average onset of disease on Day 148. Mice treated with mitoxantrone at a dose of 0.05 mg/kg three times weekly for 12 weeks following immunization had a 67% incidence of clinical disease with a significant delay in the average onset date to Day 279. These results indicate that mitoxantrone was highly effective in suppressing development of acute EAE. Mitoxantrone delayed the onset of relapsing EAE in mice, but did not fully inhibit the eventual expression of the disease. These studies suggest that the use of cytotoxic therapies in the treatment of autoimmune diseases may require periodic cycles of therapy to block disease expression.

Acute Disease↗

Specific antibodies to diphtheria toxin and type 6A pneumococcal capsular polysaccharide induced by a model of semi-synthetic glycoconjugate antigen.

A molecular model of a carbohydrate-protein conjugate is described, involving the non-toxic mutant protein CRM197, serologically related to the diphtheria toxin, covalently bound to a characterized oligosaccharide derived from the molecular structure of type 6A pneumococcal capsular polysaccharide. Physicochemical and immunochemical characteristics of this oligosaccharide-protein conjugate were consistent with a molecule showing a molar carbohydrate/protein ratio of 8, an av. mol. wt of 75,000, and retention of complete immunochemical identity when tested towards the homologous antisera. The immunological characteristics obtained after immunization of 2 animal models showed a high immunogenicity of the glycoconjugate specifically directed towards diphtheria toxin and the type 6A pneumococcal capsular polysaccharide.

Animals↗

A molecular model of artificial glycoprotein with predetermined multiple immunodeterminants for gram-positive and gram-negative encapsulated bacteria.

An artificial molecule was synthesized by covalently linking the oligosaccharide haptens derived frm Streptococcus pneumoniae type 6A and Neisseria meningitidis group C capsular polysaccharides to the non-toxic mutant protein CRM197, serologically related to diphtheria toxin. Immunochemical analysis using polyclonal and monoclonal antibodies showed in the glycoprotein the presence of specific immunodeterminants of the native polysaccharides and of the carrier protein. The immunological activity of this hybrid molecule tested in two animal models gave evidence for anamnestic induction of serum antibodies specifically directed to the three distinct native molecules. They neutralized the toxicity of diphtheria toxin, recognized the polysaccharide capsule of S. pneumoniae type 6A and 6B (group 6) strain and killed the N. meningitidis group C bacteria by complement-mediated bacterial lysis. These findings support the possibility of using in humans a multivalent antigen with immunogenic activity for several epidemiologically significant Gram-positive and Gram-negative encapsulated bacterial strains.

Animals↗

New arylpyrido-diazepine and -thiodiazepine derivatives are potent and highly selective HIV-1 inhibitors targeted at the reverse transcriptase.

A series of pyridobenzothiodiazepindioxides such as the 11-ethyl-6,8,9-trimethyl-6,11-dihydro-pyrido[2,3-f] [2,1,5]benzothiodiazepine-5,5-dioxide and arylpiridodiazepines such as the 6,7-dihydro-7-methyl-12-ethyl-pyrido[2,3-b] pyrido(2',3'-4,5]furo[2,3-f][1,4]diazepin-6(12H)-thio and the 6,7-dihydro-7-methyl-12-ethyl-pyrido[2,3-b]pyrido- [2,3-4,5]thieno[2,3-f][1,4] diazepin-6(12H)-thione were found to inhibit human immunodeficiency virus type 1 [HIV-1(IIIB)] replication at a concentration of 0.003-0.04 microM without being cytotoxic at a 3,000- to 15,000-fold higher concentration. These compounds proved effective against a variety of HIV-1 strains, including those that are resistant to 3'-azido-3' deoxythymidine (AZT), but not against HIV-2, simian immunodeficiency virus or herpes simplex virus. An HIV-1 strain containing the 188 Tyr-->His mutation in the reverse transcriptase displayed severely reduced sensitivity to the compounds. The specificity of these compounds is due to an interaction with the reverse transcription process. The 6,7-dihydro-7-methyl-12-ethyl-pyrido[2,3-b]pyrido [2,3-4,5]thieno[2,3-f][1,4]diazepin-6(12H)-thione (MEN 10979) enhanced the anti-HIV-1 activity of AZT and dideoxyinosine (ddI) in a synergistic manner. The new arylpyrido-diazepine and -thiodiazepine derivatives appear to be drug candidates for the treatment of HIV-1 infection.

Antiviral Agents↗

Development and phase 1 clinical testing of a conjugate vaccine against meningococcus A and C.

A conjugate vaccine against meningococcus A and C was prepared using the non-toxic mutant of diphtheria toxin CRM 197 as a carrier protein. Capsular polysaccharides of Neisseria meningitidis group A and C were hydrolysed and the resulting oligosaccharides were then coupled to CRM 197 in order to obtain conjugates with a carbohydrate content of 25-30%. The final vaccine that contained 11 micrograms of each oligosaccharide and 88 micrograms of CRM 197 was used to immunize mice and rabbits. After the preclinical studies which showed that the vaccine was safe and immunogenic in animal models, a pilot phase 1 clinical trial, blind versus placebo, was performed on adult volunteers. The difference between the incidence of adverse reactions associated with vaccine and placebo administration was not statistically significant. All the volunteers who received the vaccine had a significant increase in antibodies to group A and C meningococcal capsular polysaccharides after the first dose.

Animals↗

Immunity to Haemophilus influenzae type b on sample population from central Italy.

A study on natural immunity to Haemophilus influenzae type b (Hib) was carried out in the province of Siena on 474 subjects ranging in age from 3 days to 70 years. The titration of antibody to capsular polysaccharide (PRP) was performed by the radioantigen-binding assay (RABA) method. A total of 66.67% of the population studied presented an antibody level considered to be protective (greater than or equal to 0.15 microgram ml-1). Seropositivity was 5.7% in the 5-7 month age group and 29.09% in the 8-17 month age group. This rose progressively in successive age groups reaching 79.54% between 4 and 6 years old and a value greater than 90% after 7 years old. From 3 to 17 months even the geometric mean of antibodies to PRP was below the protective limit. Our data indicate that, even in Italy, the majority of the infant population is not protected against H. influenzae, and therefore that vaccination should also be introduced in this country.

Adolescent↗

RNA-lipid complexes released from the plasma membrane of human colon carcinoma cells.

Cultured cells from human colon adenocarcinoma spontaneously release structures which display an intense 31P NMR signal from RNA and mobile phospholipids. Furthermore, the DPH probe in the cell supernatant shows an intense fluorescence, thus indicating its insertion in lipid vesicles. The total membranes, prepared from the same cells, also release similar structures. The fatty acid chain signals from the mobile lipids, observable in the H NMR spectrum, and the fluorescence polarization of the DPH probe are strongly affected by RNAase digestion, thus indicating an association between RNA molecules and lipids. The enzymatic marker cytochrome c reductase was assayed to rule out possible contamination from endoplasmatic reticulum. A high alkaline phosphatase activity was instead found in the supernatant samples, thus indicating that the shed material is released by the plasma membrane.

Adenocarcinoma↗

Role of NK1 tachykinin receptors in thermonociception: effect of (+/-)-CP 96,345, a non-peptide substance P antagonist, on the hot plate test in mice.

We have tested the ability of (+/-)-CP 96,345, a novel nonpeptide substance P (SP) antagonist, to block the aversive behaviour induced by intrathecal (i.t.) administration of SP and to induce thermal antinociception in mice. (+/-)-CP 96,345 administered i.t. or i.p. selectively blocked the effect of i.t. SP while leaving the response to i.t. bombesin unaffected. At the same dose proven effective against i.t. SP, (+/-)-CP 96,345 produced thermal analgesia in the hot plate test (52 degrees C). Using isolated organs for bioassay evaluation of activity at tachykinin receptor, (+/-)-CP 96,345 was found to be a potent (pA2 8.11, c.l. 7.9-8.3) and competitive NK1 receptor antagonist while it was devoid of activity at NK2 or NK3 receptors. These findings provide clear indication for the participation of SP, via NK1 receptors, in thermal nociception.

Animals↗

Species attribution and strain typing of Oenococcus oeni (formerly Leuconostoc oenos) with restriction endonuclease fingerprints.

In several wines, malolactic fermentation is required to improve the organoleptic characters and to stabilize the final product. In order to establish a controlled malolactic fermentation in wine, easy identification and sensitive typing of strains of Oenococcus oeni (new name of the malolactic bacterium Leuconostoc oenos) used as starter cultures are necessary. To accomplish these tasks, several strains of Oenococcus oeni isolated from wines of the Chianti region (Italy), along with reference strains and strains of L. mesenteroides subsp. mesenteroides, L. carnosum, L. fallax, L. pseudomesenteroides, L. lactis and Weisella paramesenteroides, were studied with RFLP of ribosomal genes and ultrasensitive total DNA restriction pattern analysis performed on polyacrylamide gel. With each of four restriction endonucleases used, identical restriction profiles of ribosomal genes were obtained for all strains of O. oeni. These ribopatterns, being strongly dissimilar to profiles of the other lactic acid bacteria tested, appear to be well suited for the attribution of wine lactic acid bacteria to the species O. oeni. Cluster analysis performed on two total DNA restriction profile data sets showed that the species O. oeni possesses a good degree of genomic homogeneity. Very sensitive typing of strains of O. oeni was obtained with total DNA restriction profiles. The potential of an integrated approach using restriction profiles for species assignment and typing of selected malolactic bacteria is demonstrated.

Bacterial Typing Techniques↗

Strategies for comparing gene expression profiles from different microarray platforms: application to a case-control experiment.

Meta-analysis of microarray data is increasingly important, considering both the availability of multiple platforms using disparate technologies and the accumulation in public repositories of data sets from different laboratories. We addressed the issue of comparing gene expression profiles from two microarray platforms by devising a standardized investigative strategy. We tested this procedure by studying MDA-MB-231 cells, which undergo apoptosis on treatment with resveratrol. Gene expression profiles were obtained using high-density, short-oligonucleotide, single-color microarray platforms: GeneChip (Affymetrix) and CodeLink (Amersham). Interplatform analyses were carried out on 8414 common transcripts represented on both platforms, as identified by LocusLink ID, representing 70.8% and 88.6% of annotated GeneChip and CodeLink features, respectively. We identified 105 differentially expressed genes (DEGs) on CodeLink and 42 DEGs on GeneChip. Among them, only 9 DEGs were commonly identified by both platforms. Multiple analyses (BLAST alignment of probes with target sequences, gene ontology, literature mining, and quantitative real-time PCR) permitted us to investigate the factors contributing to the generation of platform-dependent results in single-color microarray experiments. An effective approach to cross-platform comparison involves microarrays of similar technologies, samples prepared by identical methods, and a standardized battery of bioinformatic and statistical analyses.

Breast Neoplasms↗