Structural studies of a polysaccharide (S-88) elaborated by Pseudomonas ATCC 31554

The structure of the extracellular polysaccharide elaborated by Pseudomonas ATCC 31554 has been investigated, methylation analyses, specific degradations, and 1H-n.m.r. spectroscopy being the main methods used. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units with the structure: ----3)-beta-D-Glcp-(1----4)-beta-D-GlcpA-(1----4)-beta-D-Glcp- (1----4)-alpha-L-[Rha or Man]-(1---- 3 increases 1 alpha-L-Rha. An unusual feature is that a sugar residue in the chain may be either L-rhamnose or L-mannose. The polysaccharide also contains O-acetyl groups (approximately 5%) which have not been located.

Structural studies of the O-specific side-chains of the Escherichia coli O 10 lipopolysaccharide

The structure of the O-specific side-chains of the Escherichia coli O 10 lipopolysaccharide has been investigated. Methylation analysis, n.m.r. spectroscopy, and various specific degradations were the principal methods used. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure, in which D-Fuc4NAcyl is 4-amino-4,6-dideoxy-D-galactose, acylated with acetic acid (60%) or D-3-hydroxybutyric acid (40%). (Formula: see text).

Structural studies of the O-antigen from Vibrio cholerae O:21

The O-antigen from Vibrio cholerae O:21 has been investigated, using n.m.r. spectroscopy, methylation analysis, and Smith degradation as the main methods. It is concluded that the O-antigen is composed of tetrasaccharide repeating-units having the following structure (in which Hep = D-glycero-D-manno-heptose). (Formula: see text).

Distribution of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in experimental animals studied by postiron emission tomography and whole body autoradiography

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a selective potent neurotoxin which has induced a syndrome similar to parkinsonism both in man and in monkeys. At autopsy degeneration of pigmented nerve cells in the pars compacta of the substantia nigra has been confirmed. The regional distribution of intravenously administered 1-(11C-methyl)-4-phenyl-1,2,3,6-tetrahydropyridine (11C-MPTP) in the brain of Rhesus monkeys was studied by positron emission tomography and the whole body distribution in mice was documented by autoradiography and by impulse counting of selected tissues. A very rapid and high uptake of 11C-MPTP derived radioactivity was seen in areas corresponding to striatum and midbrain, including the substantia nigra area. No elimination from these regions was seen during the study period of 2 h. The uptake was in the order of 7-8 times the homogenous distribution of the radioactivity in the monkey. The uptake was generally high also in other regions of the brain, but there some elimination could be distinguished. Pretreatment of the monkey with spiperone, a selective dopamine receptor antagonist, did not alter uptake nor the kinetics of the 11C-MPTP derived radioactivity. Thus 11C-MPTP does not have a high affinity for postsynaptic dopamine receptors. A remarkably high uptake of 11C-MPTP derived radioactivity was seen in the eye of the monkey. The selective uptake of radioactivity in the eye was also confirmed in pigmented but not in albino mice. The melanin affinity of MPTP may cause high intracellular concentrations of the compound or its metabolites in the melanin containing nerve cells in substantia nigra, which may explain the serious vulnerability of these neurons to MPTP.

Pharmacokinetics of terbutaline during pregnancy

Terbutaline in plasma was determined in three groups of women by gas chromatography-mass spectrometry. Eight women received a single i.v. dose of 0.25 mg terbutaline sulphate during pregnancy and 3-6 months after delivery. Mean plasma clearance was 29% higher during pregnancy than after delivery. There was a subsequent decrease in mean terminal half-life from 5.3 to 3.7 h and in mean residence time from 5.3 to 3.4 h. There was no change in volume of distribution. A second group of pregnant women in premature labour (n = 8) received oral terbutaline 5 mg t.d.s. The dosing was repeated after delivery. The mean steady state plasma concentration of terbutaline was about 30% lower during pregnancy than after delivery. A third group of women in preterm labour (n = 8) was treated with an i.v. infusion of terbutaline. The concentrations of terbutaline found on cessation of uterine contractions ranged between 12.8 and 31.5 ng/ml. At present there is no basis for formulation of a "therapeutic plasma level" of terbutaline for the treatment of preterm labour.

Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 5

The structure of the capsular polysaccharide (S5) elaborated by Streptococcus pneumoniae type 5 has been investigated by using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure: (Formula: see text) In this structure, L-PneNAc stands for 2-acetamido-2,6-dideoxy-L-talose (pneumosamine) and D-Sug for 2-acetamido-2,6-dideoxy-D-xylo-hexos-4-ulose. The latter sugar accounts for the lability of S5 towards alkali. N.m.r. spectra indicate heterogeneity in S5, most probably associated with the hexosyl-4-ulose residue.

Pregnancy-induced increase in metoprolol metabolism

Five women who developed hypertension during pregnancy received metoprolol, 10 mg iv; 3 days later they received metoprolol, 100 mg by mouth. Blood and urine samples were collected after each dose. The same procedure was repeated 3 to 6 months after delivery. The apparent oral clearance of metoprolol during pregnancy exceeded that after pregnancy by a factor of 2 to 13. As a result, after oral dosing the peak plasma concentrations during pregnancy were only 12% to 55% those after delivery, and the plasma AUCs were reduced to the same extent. Oral bioavailability increased by a factor of 1.3 to 3.7 after pregnancy. Systemic clearance after pregnancy was 26% to 97% that during pregnancy, but this difference was not significant. Metoprolol plasma protein binding was the same on both study occasions. Our data cannot be explained by a change in gastrointestinal absorption, because the urinary recovery of metoprolol and its metabolites was slightly higher during pregnancy. It is concluded that the greater metoprolol clearance during pregnancy results from increased hepatic metabolism of the drug.

Effects of adjuvants to local anaesthetics on their duration. II. Studies of some substituted dextrans and other macromolecules in rat infraorbital nerve block

The effects of adding various macromolecular substances to 2% prilocaine on duration of rat infraorbital nerve block were investigated. The tested substances consisted of dextrans with lipophilic or charged substituents as well as other neutral or highly charged macromolecules. Most of the adjuvants caused significant prolongations of sensory block. For substituted dextrans the duration of sensory block degree 3 amounted to between 120% (3% capryldextran II) and 350% (3% carboxymethyldextran) in comparison to prilocaine plain. The corresponding values for hydroxypropylstarch (3%) alginic acid (0.5%), beta-cyclodextrin (1.5%) and hyaluronic acid (0.25%) were about 170%, 285% and 380%, respectively. The results suggest that the increased duration of local analgesia by prilocaine is related to increased viscosity of the solution produced by the macromolecular compounds. The mechanism seems to be of a physical character, and hyaluronic acid seems to be worthy of further studies.

Effects of adjuvants to local anaesthetics on their duration. I. Studies of dextrans of widely varying molecular weight and adrenaline in rat infraorbital nerve block

Local anaesthetics of the amide type were studied in a modified rat infraorbital nerve block model, with which it was possible to determine varying degrees of sensory block. Of the agents investigated, 0.5% bupivacaine tended to give a longer duration of block than 2% prilocaine or 2% lidocaine, while 0.5% etidocaine had the shortest duration. The duration of prilocaine was prolonged by addition of adrenaline, 5 micrograms/ml, more than that of the other agents. Addition of dextrans of Mw 40-110 X 10(3) did not cause any prolongation of block induced by bupivacaine. When mixed with dextrans over a wide range of Mw (40-4900 X 10(3), prilocaine exhibited significant prolongations of its action by up to 200%. The extent of prolongation was dependent on the degree of block, the concentration of dextrans in the local anaesthetic solution, and the Mw of the dextran although in a less uniform way. An increase in the relative viscosity of the solutions might be a factor of importance for the prolonging effect of addition of dextran to local anaesthetics. Since a formulation providing analgesia of a long duration would be of clinical value, further studies on combinations of the comparatively low-toxicity agent prilocaine and macromolecular substances are of interest.

Effects of adjuvants to local anaesthetics on their duration. III. Experimental studies of hyaluronic acid

The effects of addition of hyaluronic acid (sodium hyaluronate, Healon) to different local anaesthetics of the amide type on the duration of sensory or motor blocks following various regional anaesthetic procedures were studied in animal experiments. In the rat infra-orbital nerve block model, the addition of 0.1-0.5% hyaluronic acid (HA) to 2% prilocaine increased the duration of sensory block of varying degrees in a dose-dependent way by up to 500% of values obtained with plain prilocaine. The duration of degree 5 blocks produced by 0.5% etidocaine and 0.5% bupivacaine was also significantly prolonged when 0.4% HA was included to 206% and 282% of control, respectively, while blocks induced by 2% lidocaine were prolonged to 123% of control. The duration of motor block following spinal anaesthesia in the mouse was prolonged in a dose-dependent way when HA was added to prilocaine, bupivacaine and etidocaine. For solutions containing 0.4% HA, prolongations to 254%, 166% and 134% of control, respectively, were obtained. A concomitant increase of latency to onset of block and failure rate occurred with increasing concentrations of HA. The duration of corneal anaesthesia in the rabbit increased by 57% and 44% when 0.3% HA was added to prilocaine and bupivacaine, respectively. The duration of infiltration anaesthesia was not affected by the addition of HA to the local anaesthetic solutions. Addition of HA had no effect on the onset, depth and duration of prilocaine-induced block of the nervous transmission in vitro. The duration of infra-orbital nerve block and spinal anaesthesia shows a significant relation to the relative viscosity of the local anaesthetic solution.

The enterobacterial common-antigen, a cyclic polysaccharide

Structural studies of the enterobacterial common-antigen, using chemical methods and fast-atom-bombardment mass spectrometry, indicate that it is a cyclic polysaccharide, composed of four, five, and, to a smaller extent, six trisaccharide repeating-units. In the structure of the antigen, given below, D-Fuc4NAc stands for 4-acetamido-4,6-dideoxy-D-galactose.

Comparison of the structures and elicitor activities of a synthetic and a mycelial-wall-derived hexa(beta-D-glucopyranosyl)-D-glucitol

The elicitor activity and structural characteristics of chemically synthesized hepta- and octa-beta-D-glucopyranosides were compared with the same properties of an elicitor-active mycelial-wall-derived hexa(beta-D-glucopyranosyl)-D-glucitol. The specific elicitor activities, retention times on reversed-phase liquid chromatography columns, glycosyl-linkage compositions, 1H NMR analyses, and glycosyl-sequence analyses of the synthetic and mycelial-wall-derived hexa(beta-D-glucopyranosyl)-D-glucitols were indistinguishable. This work provided conclusive proof that elicitor activity was associated with the structure proposed (Sharp, J. K., McNeil, M., and Albersheim, P. (1984) J. Biol. Chem. 259, 11321-11336) for the elicitor-active mycelial-wall-derived hexa(beta-D-glucopyranosyl)-D-glucitol.

Synthesis of a glucoheptaose and a glucooctaose that elicit phytoalexin accumulation in soybean

The glucoheptaose 1 and the glucooctaose 2 have been synthesized using unambiguous methods. The former is identical with an elicitor-active heptasaccharide obtained from partially hydrolyzed mycelium of Phytophthora megasperma f. sp. glycinea. The octasaccharide is also elicitor active, although to a lesser extent than the heptasaccharide. 1:R = H; 2:R = beta-D-Glcp. (Formula: see text)

CSF and plasma beta-casomorphin-like opioid peptides in postpartum psychosis

The authors measured opioid receptor-active components in the CSF of 11 women with postpartum psychosis, 11 healthy lactating women, and 16 healthy women who were not lactating. Activity that eluted with 0.2 M acetic acid 0.7-0.9 times the total volume of the column (fraction II activity) was significantly higher in the CSF of both healthy and psychotic women in the puerperium than in that of the lactating women. Very high levels of fraction II activity were seen in four psychotic patients. Material from these patients was further characterized by electrophoresis and high-performance liquid chromatography: The material migrated as bovine beta-casomorphin. Receptor-active material with the same characteristics was also found in the plasma of these four patients. The authors conclude that certain cases of postpartum psychosis are associated with the occurrence in plasma and CSF of unique opioid peptides probably related to bovine beta-casomorphin.

Structural studies of the Escherichia coli O-antigen 6

The structure of the Escherichia coli O-antigen 6 has been investigated using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the O-antigen is composed of pentasaccharide repeating-units having the following structure. (Formula: see text)

Kinetics of 11C-labeled opiates in the brain of rhesus monkeys

The regional uptake in the brain of Rhesus monkeys of i.v. administered 11C-labeled morphine, codeine, heroin and pethidine was studied by means of positron emission tomography. The technique measures the sum of parent drug and radiolabeled metabolites. (For the sake of simplicity the drug derived radioactivity is denoted by the drug name.) Morphine had a limited uptake to discrete areas of the brain. The maximum normalized uptake, with respect to dose per kilogram body weight, was about 0.2, i.e., 20% of the calculated activity if the drug had been evenly distributed throughout the body of the monkey. Maximum radioactivity appeared 30 to 45 min after injection. Morphine left the brain slowly with an estimated half-life of more than 2 hr. An area with a normalized uptake of about 1.0 was detected centrally in the lowest horizontal transsection of the skull. The origin of this area was identified as the pituitary. Codeine, heroin and pethidine were taken up to the brain to a larger extent than morphine, with maximum normalized uptakes of 2.6, 4.6 and 6.3, respectively. Maximum radioactivities of these drugs were achieved earlier and the elimination rates were faster than for morphine. Differences in the uptake of these drugs to the brain, as well as differences in time to maximal normalized uptake and rate of disappearance are considered to reflect differences in the lipophilic character between the drugs. Pethidine had the most rapid and extensive uptake followed by heroin, codeine and morphine in order of decreasing lipophilicity.

Morphine glucuronidation in the rhesus monkey: a comparative in vivo and in vitro study

The kinetics of morphine in the rhesus monkey after i.v. or oral administration including the hepatic extraction ratio determined directly in the portal and hepatic veins were compared with the glucuronidation of morphine in liver microsomes from the same animals. The plasma half-lives varied between 102 and 202 min and the apparent volume of distribution was 2.68 to 3.15 l X kg b.wt.-1. The systemic blood clearance (9.2-21.3 ml X min-1 X kg b.wt.-1) was in the same range as the estimated hepatic blood clearance (9.7-23.9 ml X min-1 X kg b.wt.-1). After i.v. administration, the blood concentrations of morphine-3-glucuronide ( M3G ) were 8 to 11 times higher than those of morphine. The molar blood concentration ratio between morphine-6-glucuronide and M3G was 0.04 or less. The ratio between the metabolite levels in blood was similar to the relative formation rates for M3G and morphine-6-glucuronide in liver microsomal preparations (less than .039). The intrinsic hepatic metabolic clearance of morphine as estimated from the apparent enzyme kinetic constants Vmax and Km for the formation of the major M3G metabolite was used to predict the hepatic extraction ratio. The predicted values of the hepatic extraction ratio (0.09-0.14) were, however, underestimates of the experimentally determined hepatic extraction ratio, which varied between 0.61 and 0.74. This indicates that unknown factors in the liver microsomal glucuronidation preclude the use of enzyme kinetics parameters obtained in vitro for the prediction of the hepatic extraction ratio of morphine. For some drugs that are oxidized it has been shown previously that such prediction from in vitro data is possible.

Audibility of an artificial third heart sound in relation to its frequency, amplitude, delay from the second heart sound and the experience of the observer

The possibility of detecting synthetic third heart sounds was studied. A special unit was used that added a sound to a previously recorded phonocardiogram. The sound could be changed in frequency, amplitude and delay from the second heart sound. Four groups of observers--cardiologists, residents, nurses and students--listened to 32 random examples. Detection rate increased with experience of the observer (p less than 0.0001) as well as with amplitude (p less than 0.0001), frequency (p less than 0.0001) and delay of the sound (p less than 0.05). The sensitivity was highest among the cardiologists, but the specificity was not different between the groups. Data from this study indicate that the audibility of the third heart sound depends on several important factors. The sound should usually be audible, but variability of results were considerable even among experienced cardiologists. A quantified phonocardiographic recording should be used for validation.

Comparison of different clearance estimates for metoprolol in the rhesus monkey

After oral administration, the fraction of unchanged drug available systemically is predominantly governed by hepatic drug-metabolizing enzyme activity and/or binding to the liver. If the "well stirred" model for hepatic elimination mimics reality, the apparent oral clearance (Clo) of metoprolol, a drug which is completely absorbed and metabolized only by the liver, should reflect the intrinsic clearance (Cli), i.e., the maximum enzyme activity in absence of blood flow limitations. According to theory, the hepatic venous (hv) drug concentrations after an i.v. dose are also a function of Cli. This postulate has previously been verified in the isolated perfused rat liver by others and has now been tested by us in the intact rhesus monkey. We have compared Clo, Cli and the systemic clearance (Cls) of metoprolol in six rhesus monkeys catheterized in the hepatic and femoral veins (hv; fv). They were given simultaneously 37 to 73 micrograms of [3H]metoprolol i.v. and 9 mg of metoprolol per kg b.w. orally. Unlabeled drug was analyzed in plasma by gas chromatography and 3H-labeled metoprolol by liquid scintillation after liquid chromatography separation. The Cls [dose i.v./area under the blood concentration vs. time curve in the femoral vein (AUCs)] varied between 27 and 32 ml X kg-1 X min-1. As expected, the Clo (doseo/AUCs) was considerably higher and ranged from 89 to 147 ml X kg-1 X min-1. The Cli (dosei.v./AUChv) was in the same range as Clo (46-163 ml X kg-1 X min-1). The determined oral availability was 19 to 31% with a mean of 25.(ABSTRACT TRUNCATED AT 250 WORDS)

Methodological problems in studies on hypertension therapy during pregnancy

As yet, no distinct aetiological factor underlying hypertension in pregnancy has been disclosed, and there is therefore no clearcut treatment for this condition. The lack of well-defined end-points makes it difficult to plan and evaluate the results of studies on the treatment of hypertension during pregnancy. However, we cannot await the solution to the puzzle of pre-eclampsia before providing treatment for this hypertension. Well-designed investigations to determine the most effective form of such treatment are therefore of great value and must be carried out in spite of the many problems associated with these studies. If given due consideration, as discussed in this paper, this problem can be alleviated.

The incidence of hypertensive disease in pregnancy

Incidence figures for hypertensive disease in pregnancy (HDP) vary widely in epidemiological studies due to variations in definitions, the occurrence of risk factors and differing methods of data collection. In Uppsala county all pregnant women with a diastolic blood pressure of 90 mmHg or more were prospectively registered within a 2-year-period. The incidence of hypertension noted in the antenatal clinics was found to be 7.2%. In 56% of the cases hypertension was first noted after 37 weeks of gestation. The group of patients presenting before term with hypertension not normalized by bed rest in hospital and without complicating factors was only 14% of the whole material. The implications of the findings for discussions on therapy and complications in HDP are discussed.

Structural studies of the Escherichia coli O-antigen 25

The structure of the Escherichia coli O-antigen 25 has been investigated using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the O-antigen is composed of pentasaccharide repeating-units having the following structure.

Styrene oxide metabolism in rhesus monkey liver: enzyme activities in subcellular fractions and in isolated hepatocytes

The activity and the kinetic behavior of expoxide hydrolase were studied in various subcellular fractions of rhesus monkey liver isolated by differential centrifugation. The purity of the fractions was estimated by morphometric electron microscopy. Hydrolase activity was measured by a specific radiometric assay with [7-3H]styrene oxide as substrate. All isolated subcellular fractions catalyzed the hydration of styrene oxide at a significant rate. With a saturating concentration of substrate (1 mM), the enzymatic activity (nanomole of product per minute per milligram of protein; mean +/- S.E.) turned out to be 1.51 +/- 0.45 (nuclear fraction), 3.50 +/- 1.11 (mitochondrial fraction), 14.8 +/- 2.26 (microsomal fraction) and 1.69 +/- 0.37 (soluble fraction). The hydrolase obeyed Michaelis-Menten kinetics in each fraction. Vmax (nanomole per minute per milligram; mean +/- S.E.) was 1.64 +/- 0.65 (nuclear fraction) 3.87 +/- 1.71 (mitochondrial fraction), 19.8 +/- 5.4 (microsomal fraction) and 2.72 +/- 1.36 (soluble fraction). The Km (millimole; mean +/- S.E.) values in the fractions were 0.09 +/- 0.02, 0.07 +/- 0.01, 0.23 +/- 0.15 and 0.64 +/- 0.40, respectively. The metabolism of styrene oxide was also studied in isolated hepatocytes from rhesus monkey. These cells hydrated the substrate easily whereas the conjugation of styrene oxide with glutathione was not measurable. Our results show that epoxide hydrolase is present in all subcellular fractions of the rhesus monkey liver. Styrene oxide is preferentially metabolized by hydration to styrene glycol in the isolated hepatocytes of this species and no conjugation with glutathione was found under the incubation conditions used.

Exchange of amino acids by muscle and liver in sepsis

The amino acid "central fractional clearance rate" (CFCR), the ratio of the rate of amino acid entry into the extracellular pool to the size of the pool, is a measure of amino acid uptake and clearance by liver and other visceral tissues. In nine normal postabsorptive persons, the mean CFCR was 5%, compared with 21% in 31 seriously infected patients. For comparative purposes, biopsy specimens of liver and muscle were obtained for incubation. In infected patients, the rate of hepatic incorporation of tyrosine into protein was three times that in noninfected patients and correlated well with the CFCR. There was no significant difference in hepatic tyrosine oxidation. In muscle from infected patients, net protein degradation was six times that in noninfected patients. Incubated tissues from rats behaved similarly. Thus, accelerated transfer of amino acid from muscle to viscera for protein synthesis occurs in humans with sepsis, as it does in animals. The CFCR demonstrated the importance to survival of visceral amino acid uptake; it was 35% in surviving patients, and only 19% in those who died.

Cohort study of oestrogen treatment and the risk of endometrial cancer: evaluation of method and its applicability

A Swedish study of the risk of endometrial cancer associated with oestrogen treatment was started in 1977. A prospective design was chosen and a cohort of 23,233 women receiving oestrogen medication was collected over a three-year period. Cohort members were recruited on the basis of prescription forms for oestrogens produced by all 120 pharmacies in a defined geographical region, resulting in comprehensive coverage of that region. A questionnaire study of a random sample (1/30) of the cohort permitted mapping of confounding factors, estimation of drug compliance and detailed characterization of oestrogen and progestagen exposures. Efficient follow-up of the cohort members was achieved by linkage of identity numbers of cohort members and those of all incident cases of endometrial cancer in the region. The expected outcome was calculated on the basis of accumulated person-years of observation in the entire cohort - and in subgroups - and age-specific incidence rates of endometrial cancer in the reference population. The present design may be generally useful for post-marketing studies of the association between drug use and side-effects.

Increased oral clearance of metoprolol in pregnancy

The disposition of oral metoprolol was studied in 5 women during the last trimester of pregnancy and 3 to 5 months after delivery. After a single oral dose of 100 mg the individual peak plasma concentration in the pregnant state was only 20-40% of that after pregnancy. The plasma half-lives of metoprolol were about the same during (average 1.3 h) and after pregnancy (average 1.7 h). By contrast, the area under the plasma concentration versus time curve was much smaller during (mean 262 nmol/1 X h) than after (mean 1298 nmol/1 X h) pregnancy, resulting in an average apparent oral clearance (Clo) of metoprolol that was 4.4 times higher during (362 ml X kg-1 body-weight X min-1) than after pregnancy. The increased Clo in pregnancy is assumed to be due to enhanced hepatic metabolism of the drug. The possible clinical consequence of the difference in the disposition of metoprolol is discussed.

A 500-MHz proton-magnetic-resonance study of several fragments of the carbohydrate-protein linkage region commonly occurring in proteoglycans

The proton-magnetic-resonance spectra of three partial structures of the carbohydrate-protein linkage region that frequently occurs in proteoglycans, namely, beta-D-Galp-(1 leads to 3)-beta-D-Galp-(1 leads to 4)-beta-D-Xylp-(1 leads to O)-L-Ser, were recorded in 2H2O at 500 MHz; they could be completely interpreted, both for the glyco-serines and for the corresponding glyco-xylitols. The chemical shifts and the coupling constants were refined by computer simulation of the spectra. The change in the chemical shift of H-4 of a D-galactopyranosyl residue upon substitution at C-3 by a beta-D-galactopyranosyl group is proposed to be characteristic for this particular attachment, making H-4 of galactose a structural-reporter group. The three constituting monosaccharides adopt the 4C1 (D) ring conformation. The terminal galactopyranosyl group and the internal galactopyranosyl residue differ as to the population of rotamers around the C-5/C-6 axis. Concomitantly, the flexibility of their glycosidic linkages is distinct.

Structural studies of the Vibrio cholerae O-antigen

The dominant part of the O-antigen of Vibrio cholerae is a homopolysaccharide composed of (1 leads to 2)-linked 4-amino-4,6-dideoxy-alpha-D-mannopyranosyl (perosaminyl) residues, in amino groups of which are acylated by 3-deoxy-L-glycero-tetronic acid. Most of the amino sugar is decomposed during acid hydrolysis. Treatment of the polymer with anhydrous hydrogen fluoride, which cleaves the glycosidic linkages but does not cause N-deacylation, followed by acid hydrolysis under mild conditions, produced the monomer in good yield. Treatment of the N-deacylated polysaccharide with nitrous acid caused deamination with concomitant rearrangements, typical of 4-amino-4-deoxyhexopyranosyl residues in which the amino group occupies an equatorial position.

Fetal jejunal atresia and intrauterine volvulus--a case report

Ultrasonic B-scan not only confirms the clinical suspicion of polyhydramniosis, but will also in many cases diagnose the etiology. In case of a high intestinal atresia, two or more fluid-filled structures are seen in the fetal abdomen. In case of a congenital defect combination, intestinal atresia is generally associated with malrotation. This combination is frequently complicated by a midgut volvulus. The report describes a case of intrauterine volvulus with a surviving child. Repeat CTG-recordings in this case led to an acute caesarean section, when the CTG turned from normal to silent pattern.

Structural studies of the capsular polysaccharide elaborated by Haemophilus influenza type d

The structure of the capsular polysaccharide elaborated by Haemophilus influenzae type d has been investigated, methylation analysis and n.m.r. spectrometry being the principal methods used. It is concluded that the polysaccharide is composed of repeating units having the structure: leads to 4)-beta-D-GlcpNAc-(1 leads to 3)-beta-D-ManpNAcA-(1 leads to. In addition, single residues of L-alanine, L-serine, or L-threonine, in the proportions 2:2:1, are linked, through their amino groups, to C-6 of the 2-acetamido-2-deoxy-beta-D-mannopyranosyluronic acid residues. The degree of substitution (75-85%) varies for different preparations.

Structural studies of the O-specific side-chain of the lipopolysaccharide from Escherichia coli O 55

The structure of the O-specific side-chains of the lipopolysaccharide from Escherichia coli O 55 has been investigated, methylation analysis, specific degradations, and n.m.r. spectroscopy being the principal methods used. It is concluded that the O-specific side-chains are composed of pentasaccharide repeating-units having the following structure [where Col stands for colitose (3,6-dideoxy-L-xylo-hexose)].(See formula in text).

Structural studies on the hexose region of the core in lipopolysaccharides from Enterobacteriaceae

The structures for the hexose regions of cores from Enterobacteriaceae lipopolysaccharides have been investigated, using specific degradations and 1H NMR studies as the principal methods. Complete structures for these regions in the Salmonella, the Escherichia coli R1, R2, R3, R4, the E. coli K12 and E. coli B cores are proposed. Some complementary information on the structure of the heptose region has also been obtained.