The structure of the Vibrio mimicus W-26768 O-antigen polysaccharide has been investigated by sugar and methylation analyses, Smith degradation, and NMR spectroscopy. It is proposed that it is composed of chains of beta-(1-->4)-linked 3,6-dideoxy-3-[(R)-3-hydroxybutyramido]-D-glucopyranosyl residues (D-Qui(p)3NR), approximately 60% of which are substituted in the 2-position with 2-acetamido-2-deoxy-alpha-D-galactopyranosyl groups. The polysaccharide does not seem to be composed of oligosaccharide repeating units but has a less regular structure, schematically indicated below. [formula: see text]

Carbohydrate Conformation↗

PubMed1993

Structural studies of Vibrio fluvialis M-940 O-antigen polysaccharide.

The structure of the Vibrio fluvialis M-940 O-antigen polysaccharide has been investigated by sugar and methylation analyses, specific degradations, NMR spectroscopy, and mass spectrometry. It is proposed that it consists of a heptasaccharide unit having the following structure. alpha-L-Rhap-(1-->2)-alpha-L-Fucp-(1-->2)-alpha-D-Galp-(1--> 2)-alpha-L-Fucp- (1-->3)-beta-D-GlcpA-(1-->4)-alpha-L-Rhap-(1-->3)-beta-D-Glc pNAc-(1--> The heptasaccharide is most probably linked to the 3-position of an alpha-D-galactopyranosyl residue in the core.

Carbohydrate Conformation↗

PubMed1993

The prevalence of type 1 diabetes mellitus at follow-up of Swedish infants congenitally infected with cytomegalovirus.

In a Swedish prospective study of congenital cytomegalovirus (CMV) infection, 76 infants were shown to be infected among 16,474 newborns screened by virus isolation in urine. Seventy-three of the excreters were followed up and one developed Type 1 diabetes, as compared to 38 of the 19,483 children born during the same period (p = 0.14, Fisher's one-tailed test). Thus we found no evidence that the combined finding of congenital CMV infection and Type 1 diabetes mellitus was related.

Autoantibodies↗

PubMed1992

Distribution of substituents in O-(2-hydroxypropyl) derivatives of cyclomalto-oligosaccharides (cyclodextrins: influence of increasing substitution of the base used in the preparation, and of macrocyclic size.

Samples of O-(2-hydroxypropyl)derivatives of cyclomaltoheptaose (beta-cyclodextrin) with increasing substitution were prepared by withdrawing aliquots at different times from a reaction mixture containing cyclomaltoheptaose and an excess of (S)-propylene oxide in 0.39 M aqueous sodium hydroxide. The distributions of substituents between the different molecules and between the different alpha-D-glucopyranosyl residues in these samples were determined by mass spectrometry and methylation analysis, respectively. The solubilities of the samples and their association constants with phenolphthalein were also determined. The relative reactivities at O-2 and O-3 versus O-6, calculated using Spurlin's equations, decreased with increasing degree of substitution, probably because of steric hindrance. No significant differences were observed when different strong bases were used as promoters of the hydroxypropylation of cyclomaltoheptaose. The hydroxypropylation of cyclomaltohexaose (alpha-cyclodextrin) and cyclomalto-octaose (gamma-cyclodextrin) was briefly investigated.

Carbohydrate Conformation↗

PubMed1991

Synthesis of some 2-O-(2-hydroxyalkyl) and 2-O-(2,3-dihydroxyalkyl) derivatives of cyclomaltoheptaose.

On alkylation of cyclomaltoheptaose with oxiranes, promoted by alkali of low concentration, substitution at secondary positions, particularly at O-2, is favoured. The reaction has been used to prepare the 2-O-[(R)- and (S)-2-hydroxypropyl], 2-O-(2-hydroxy-2-methylpropyl), 2-O-[(R)- and (S)-2,3-dihydroxypropyl], and 2-O-[(R)- and (S)-2,3-dihydroxy-2-methylpropyl] derivatives. Each of these derivatives is less soluble in water than cyclomaltoheptaose, and their complexes with toluene, in contrast to that of cyclomaltoheptaose, are well soluble in water.

Carbohydrate Conformation↗

PubMed1991

Structural studies of the Vibrio cholerae O:3 O-antigen polysaccharide.

The structure of the Vibrio cholerae O:3 O-antigen polysaccharide has been investigated, mainly by n.m.r. spectroscopy, mass spectrometry, sugar and methylation analysis, and specific degradations, and is proposed to involve the following tetrasaccharide repeating-unit. [formula: see text]. In this structure, D-D-Hep is D-glycero-D-manno-heptose, Asc is 3,6-dideoxy-L-arabino-hexose (ascarylose), and Sug is 2,4-diamino-2,4,6-trideoxy-D-glucose (bacillosamine) in which N-2 is acetylated and N-4 is acylated with a 3,5-dihydroxyhexanoic acid. That the 2,4-diamino-2,4,6-trideoxy-D-glucose residue is linked through O-3 and not through one of the hydroxyl groups in the 3,5-dihydroxyhexanoyl group is indicated but not definitely proved. The configuration of the latter group has not been determined. The f.a.b.-mass spectrum of the methylated O-antigen indicates that the structure given above also represents the biological repeating-unit.

Carbohydrate Conformation↗

PubMed1991

Structural studies of a rhamnogalacturonan from the stipules of Musanga cercropoides.

The major water-soluble polysaccharide isolated from the stipules of Musanga cercropoides has been investigated, using n.m.r. spectroscopy, methylation analysis, and solvolysis in liquid hydrogen fluoride as the main methods. It is concluded that the polysaccharide is of the rhamnogalacturonan type and is, at least mainly, composed of tetrasaccharide repeating-units having the following structure [formula: see text] The polysaccharide further contains approximately two O-acetyl groups per repeating unit, which have not been located.

Carbohydrate Conformation↗

PubMed1991

Cross-linked, degradable starch microspheres as carriers of paramagnetic contrast agents for magnetic resonance imaging: synthesis, degradation, and relaxation properties.

Biodegradable particles were produced by the cross-linking of starch with epichlorohydrin. Diethylenetriaminepenta-acetic acid (DTPA) was covalently linked to the particles by using DTPA bisanhydride. The small, gadolinium-labelled particles were 40-260% more efficient in vitro proton relaxation agents than the corresponding unbound chelate gadolinium-DTPA. The relaxation properties were dependent on the metal chelate, the particle size, the metal content, and the degree of substitution (d.s.). For the small gadolinium-DTPA particles, an increased d.s. decreased the rate of degradation by alpha-amylase.

Biodegradation, Environmental↗

PubMed1991

Structural studies of the extracellular polysaccharide elaborated by Azotobacter vinelandii strain 1484.

The structure of the extracellular polysaccharide from Azotobacter vinelandii strain 1484 has been investigated, specific degradations and n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of tetrasaccharide repeating-units having the following structure, [sequence: see text] in which Sug is 3-deoxy-D-threo-hexulosonic acid. The polysaccharide also contains a non-stoichiometric amount of O-acetyl groups, distributed over at least two positions.

Azotobacter↗

PubMed1991

Stability and change of personality in old age and its relation to survival.

Stability of personality characteristics with increasing age was analyzed in a Swedish longitudinal study using a modified version of the Rod-and-Frame Test. This test was analyzed in a serial manner in order to emphasize cognitive style. Two important findings emerged. First, during the 6 years between the ages of 67 and 73, 80% of the study participants showed stability in the field independence-dependence dimension. Second, stability of the field independence-dependence trait between ages 67 and 73 predicted survival to age 83, whereas destabilization (i.e., changes of Rod-and-Frame Test classification) was significantly associated with earlier death. In most cases, destabilization meant that field-independent subjects became field dependent. The results are discussed in relation to dispositional and situational factors. Causative factors for destabilization are hypothesized.

Aged↗

PubMed1991

Glucuronidation of morphine and some drug oxidation reactions in liver microsomes from pregnant and non-pregnant rhesus monkeys.

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7-Alkoxycoumarin O-Dealkylase↗

PubMed1991

Maternal blood volume in placenta of the rhesus monkey measured in vivo by positron emission tomography.

The relative volume of the intervillous space of the placenta of the rhesus monkey was measured in vivo using positron emission tomography (PET), a noninvasive tracer technique. 11CO-Hb and 68GaCl3 were both used in three experiments and 68Ga-EDTA in two. The tracers were administered intravenously as bolus doses to 6 pregnant monkeys during 7 different pregnancies. Measurements with 11CO-Hb gave a volume of 48.0% of the total placental volume. Transplacental transfer of 11CO to the fetal circulation is probably a minor problem due to the small fetal blood volume and the prolonged time before the same concentration is reached in the maternal and fetal blood. Measurements with 68GaCl3, which binds to transferrin, gave an intervillous space volume of 55.6% of the placental volume. The concentration of radioactivity in the placenta did not attain a steady state, indicating a clearance of the tracer from the blood only to a small extent. Measurements with 68Ga-EDTA displayed a volume of 60.4% of the placental volume. Transplacental transfer and the additional distribution of radioactivity to fetal and maternal extracellular spaces, including the placenta, when 68Ga-EDTA was used will make this tracer unsuitable in measurements of the blood volume of the placenta with PET.

Animals↗

PubMed1991

Positron emission tomography and compartment modeling in analysis of the placenta.

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Animals↗

PubMed1991

Measurement of fibronectin concentration in benign and malignant ascites.

Fifty-eight consecutive patients who were admitted to two departments of general surgery with ascites of unknown origin were investigated by measurement of ascitic fluid fibronectin concentration in a prospective study. A fibronectin concentration of 100 ml/l or more was chosen as indicative of malignant disease. In 40 patients with malignant disease, the median fibronectin concentration was 160 mg/l (interquartile range 120-270, range 20-560). In 18 patients with ascites from benign disease the corresponding figures were 40 mg/l (30-70, 20-90) (p less than 0.01). The diagnostic specificity (predictive value of a positive test) was 1.00 (34/34) (95% confidence interval 0.90 to 1.00), while the diagnostic sensitivity (predictive value of a negative test) was 0.75 (18/24) (95% CI 0.53 to 0.90). In this series an ascitic fluid fibronectin concentration of 100 mg/l or more indicated malignant disease, but a lower value did not exclude it. The test should be investigated in combination with another test with high diagnostic sensitivity to optimise its diagnostic value.

Adult↗