Differential lead retention in zircons: implications for nuclear waste containment.

An innovative ultrasensitive technique was used for lead isotopic analysis of individual zircons extracted from granite core samples at depths of 960, 2170, 2900, 3930, and 4310 meters. The results show that lead, a relatively mobile element compared to the nuclear waste-related actinides uranium and thorium, has been highly retained at elevated temperatures (105 degrees to 313 degrees C) under conditions relevant to the burial of synthetic rock waste containers in deep granite holes.

Studies on artificial oligosaccharide-protein antigens: induction of precipitating antibodies to defined epitopes on natural and synthetic dextrans and mannans.

Seventeen di- and trisaccharides, composed of alpha-1-6-, alpha-1-2-, alpha-1-3- and alpha-1-4-linked glucosyl and alpha-1-6- and alpha-1-2-linked mannosyl residues, were synthesized. The oligosaccharides (OS) were transformed into the corresponding 2-(4-aminophenyl) ethyl alpha-D-glucosides or mannosides, which were either diazotized or converted into isothiocyanato derivatives and then coupled to BSA, edestin or hemocyanin to give artificial antigens. In this way immunogenic analogues of branched natural and linear synthetic dextrans, linear synthetic mannans and glucomannans were obtained. Upon immunization of rabbits with these conjugates, antibodies to the OS moieties carrying alpha-1-6, alpha-1-2 and alpha-1-3 glucosyl and alpha-1-6 mannosyl residues were elicited. These antibodies cross-reacted with and precipitated natural or synthetic polymers carrying the corresponding epitope pattern. The minimal size of an immunogenic OS residue required for cross-reactivity with the corresponding polymer was found to be either two or between one and two monosaccharide units. To obtain maximum and reliable elicitation of anti-OS antibodies of IgG isotype the use for coupling of an OS density corresponding to 10-25 moles of OS/mole of BSA is recommended. Other strongly immunogenic carriers may be used. In the case of homopolymers, each OS residue should have a length of at least six-eight sugar units.

An ELISA employing a Haemophilus influenzae type b oligosaccharide-human serum albumin conjugate correlates with the radioantigen binding assay.

An ELISA measuring total Ig antibodies to the capsular polysaccharide of Haemophilus influenzae type b (HbPs) in human sera using an antigen composed of Haemophilus b oligosaccharides conjugated to human serum albumin (HbO-HA) was shown to have an excellent correlation to the radioantigen binding assay (RABA). When 214 sera with different anti-HbPs levels were assayed for total Ig by HbO-HA ELISA and by RABA the correlation coefficient was 0.917 and the paired t test p value was 0.575. Use of competitive ELISA employing soluble HbPs, HbO-HA and human albumin as competitors, showed that the HbO-HA ELISA was specific for antibodies to HbPs. The HbO-HA ELISA yielded reproducible results both within and between laboratories. The HbO-HA ELISA can also be used to determine the isotype of anti-HbPs antibodies by using isotype specific enzyme conjugates. The sum of the IgG, IgA and IgM HbO-HA ELISA results had excellent correlation to the RABA results (correlation coefficient = 0.976). Thus, the HbO-HA ELISA can be substituted for the classical RABA and also be utilized for quantitating the isotype of the anti-HbPs antibodies.

Gastric antisecretory 9H-xanthen-9-amines.

A series of 9H-xanthen-9-amines possessing a wide variety of nitrogen substituents at C-9 was prepared for evaluation of gastric antisecretory activity. These substituents included the acetamidine, imidate, pyrimidine, thiazoline, quinuclidine, 2-hydrazinopyridine, aminopiperidine, aminoalkylimidazole, and aminoalkylpyridine moieties. The majority of compounds in this series inhibited gastric acid secretion when tested orally in the pylorus-ligated rat. Potency was increased by intraduodenal administration and diminished by incubation with gastric juice, suggesting partial degradation of the compounds in the gastric environment. A representative example, 3-(9H-xanthen-9-ylamino)-1-ethylpiperidine, exhibited similar activity in dogs, although no free compound could be detected in the blood. It is therefore hypothesized that this compound is either rapidly bound to tissue and/or metabolized to an active species.

Safety and immunogenicity of Haemophilus influenzae type b oligosaccharide-CRM197 conjugate vaccine in infants aged 15 to 23 months.

A total of 268 infants aged 15 to 23 months received one dose of a vaccine composed of Haemophilus influenzae type b oligosaccharides covalently linked to the nontoxic diphtheria toxin variant CRM197 (HbOC; HibTITER). Side effects associated with vaccination were infrequent, transient, and mild. One month after a single vaccination, the anti-H influenzae type b capsular polysaccharide antibody concentration rose from a geometric mean prevaccination level of 0.20 microgram/mL to 13.77 micrograms/mL. Of these infants, 99% had a postvaccination level greater than or equal to 1.00 microgram/mL, a level associated with long-term protection. The immune response was long-lived: all of the children who were monitored 17 to 27 months after vaccination had concentrations greater than or equal to 1.00 microgram/mL. The anti-H influenzae type b capsular polysaccharide antibody generated was predominantly of the IgG isotype and IgG1 subclass. The immune sera had bactericidal activity in vitro and conferred passive protection in the infant rat meningitis model.

Safety and immunologic response to Haemophilus influenzae type b oligosaccharide-CRM197 conjugate vaccine in 1- to 6-month-old infants.

A Haemophilus influenzae type b oligosaccharide-CRM197 conjugate (HbOC) vaccine was evaluated for safety and immunogenicity in 432 infants 1 to 6 months of age. In a multicenter study involving 10 sites in six states, infants were vaccinated with three 10-micrograms doses of HbOC at 2-month intervals. Side effects associated with vaccination were mild, transient, and occurred in fewer than 2% of the subjects. More than 90% of infants of all ages responded after two doses, and more than 98% had anti-H influenzae type b capsular polysaccharide (HbPs) antibody levels greater than or equal to 1 microgram/mL after three doses. One month after the third vaccination, the geometric mean anti-HbPs antibody levels were 16.84, 26.23, and 29.11 in infants initially vaccinated at 1 to 2, 3 to 4, and 5 to 6 months of age, respectively. A long-term antibody response was observed; more than 80% of these infants had anti-HbPs levels greater than or equal to 1 microgram/mL at 2 years of age. The HbOC generated an immune response characteristic of a protein antigen; IgG anti-HbPs antibodies of IgG1 subclass predominated and the response could be boosted. The immune sera killed H influenzae type b when evaluated in an in vitro bactericidal assay. The data indicate that HbOC safely primed and boosted the immune system of young infants, providing long-lasting protective levels of anti-HbPs antibodies.

Patient selection and the assessment of blood pressure in clinical trials.

A new method for selecting patients with mild-to-moderate hypertension who are appropriate for entry into clinical trials and a technique for assessing small but statistically significant decreases in diastolic blood pressure resulting from drug therapy are described. In this method, mild-to-moderate hypertension is defined to exclude subjects whose diastolic blood pressure decreases while they are taking placebo and to exclude subjects with highly variable diastolic blood pressure. A subject receives placebo for four weeks, during which time diastolic blood pressure while supine is measured three times on a single day of each week, the time between measurements not being less than 30 minutes. With the 12 measurements obtained during the four-week placebo period, the following calculations are made: an average of the 12 measurements; and average of the three measurements obtained on a given day, yielding the average diastolic blood pressure per week; and the range of the 12 measurements. Subjects are selected for study if their average diastolic blood pressure per week for the four-week placebo period is neither below 95 nor above 115 mmHg, if their average diastolic blood pressure per week does not decrease successively from week 1 to week 4, and if the range of the 12 measurements of diastolic blood pressure recorded over the four-week placebo period does not exceed 28 mmHg (equivalent to a standard deviation of 8.5). Use of the method is demonstrated in the selection of 63 patients for a double-blind study of two antihypertensive drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Antipyretic testing of commercial aspirin formulations in rats.

Four commercial aspirin formulations and aspirin powder USP were assayed in yeast-fevered rats for antipyretic activity. Tablets allowed to disintegrate spontaneously prior to dosing yielded aggregates of various sizes which failed to produce uniform patterns of antipyresis. When tested at smaller, more uniform particle sizes of total product, consistent, statistically significant antipyresis was observed with no significant variation among formulations. The ED50 values and parallel line assays were homogeneous.

The synthesis of antigenic determinants for yeast D-mannans and a linear (1to 6)-alpha-D-gluco-D-mannan, and their protein conjugates.

2-O-Benzoyl-3,4,6-tri-O-benzyl-1-O-tosyl-D-mannopyranose and 2,3,4-tri-O-benzyl-6-O-(N-phenylcarbamoyl)-1-O-tosyl-D-glucopyranose were allowed to react with partially blocked 2-[4-(ptoluensulfonamido)phenyl]ethyl alpha-D-manno- and gluco-pyranosides. Disaccharides having alpha-D-Manp-(1 to 2)-alpha-D-Manp, alpha-D-Manp-(1 to 6)-alpha-D-Glcp, alpha-D-Manp-(1 to 6)-alpha-D-Manp, and alpha-D-Glcp-(1 to 6)-alpha-D-Manp structures, and a branched trisaccharide having the structure alpha-D-Manp-(1 to 2)-[alpha-D-Manp-(1 to 6)]-alpha-D-Manp were synthesized. The oligosaccharid:s were deblocked with sodium in liquid ammonia to give glycopyranosides having a free primary aromatic amine which were converted into isothiocyanate derivatives with thio-phosgene. The functionalized oligosaccharides were then coupled to bovine serum albumin to give protein conjugates.

The synthesis of alpha and beta-(1 less than 2) and-(1 less than 3)-linked glucopyranose disaccharides and their protein conjugates.

2,3,4-Tri-O-benzyl-6-O-(N-phenylcarbamoyl)-1-O-tosyl-D-glucopyranose and 3,4,6-tri-O-benzyl-2-O-p-nitrobenzoyl-1-O-tosyl-D-glucopyranose were allowed to react with partially blocked 2-[4-p-toluenesulfonamido) phenyl]ethyl alpha- and beta-D-glucopyranosides. Disaccharides having the structure alpha-D-Glcp-(1 goes to 2)-alpha-D-Glcp, alpha-D-Glcp-(1 goes to 3)-alpha-D-Glcp, beta-D-Glcp-(1 goes to 2)-beta-D-Glcp, and beta-D-Glcp-(1 goes to 3)-alpha-D-Glcp were synthesized. The oligosaccharides were debenzylated with sodium in liquid ammonia to give disaccharides having a free primary aromatic amino group, which were converted into isothiocyanate derivatives and then coupled to various proteins to give the corresponding conjugates.

Synthesis and conformational studies of 2-beta-chloro, 1-alpha-fluoro, and 2-beta-fluoro derivatives of 2-deoxy-N-acetyl-neuraminic acid.

5-Acetamido-4,7,8,9-tetra-O-acetyl-2,3,5-trideoxy-2-fluoro-D-glycero-alp ha- and -beta-D- galacto -2- nonulosonic acid methyl esters and the beta-chloro analog were synthesized from N-acetylneuraminic acid. Their 1H- and 13C-n.m.r.spectra were completely assigned by using single-frequency decoupling, off-resonance decoupling, and spin-simulation programs. Bond angles estimated from the 1H coupling-constants indicate that all of the compounds adopt the 2C5 (L) conformation with minor conformational differences in the C3 side chain. 5-Acetamido-2,3,5,-tri-deoxy-2-fluoro-D-glycero-alpha- and -beta-D- galacto -2- nonulosonic acid and their methyl esters were also prepared.

Regioselective alkylation and acylation of carbohydrates engaged in metal complexes.

Substituted carbohydrate derivatives (D-gluco, D-manno, and D-galacto) having two free hydroxyl groups were converted into their metal chelates by reaction with sodium hydride and a metal chloride (cupric or mercuric) in either oxolane or 1,2-dimethoxyethane. Reaction of these metal chelates with allyl, benzyl, or methyl iodide, or acetic anhydride or benzoyl chloride, gave a mixture of di-, mono-, and un-substituted products in which one monosubstituted derivative preponderated. In the alkylation of copper chelates, disubstitution was absent. Appropriate choice of metal ion and organic reagent often permits selective substitution on either of two hydroxyl groups. Products were separated by liquid chromatography, and characterized by 1H- and 13C-n.m.r. spectroscopy.

Investigation of the nanofibrillar morphology in silk fibers by small angle X-ray scattering and atomic force microscopy.

Small angle X-ray scattering (SAXS) and atomic force microscopy (AFM) measurements have been shown to be consistent with the presence of nanofibrils in the cocoon silk of Bombyx mori and the dragline silk of Nephila clavipes. The transverse dimensions and correlation lengths range from >> 59 to 220 nm and in the axial direction from >> 80 to 230 nm. Also, the two-dimensional Fourier transforms of the height profiles of AFM topographic images of interior surfaces of B. mori follow a power law approximately the same as that for the Porod region of the SAXS data. In this manner, the AFM can be used to help remove ambiguity about the scatterers responsible for SAXS patterns.

Synthetic peptide representing a T-cell epitope of CRM197 substitutes as carrier molecule in a Haemophilus influenzae type B (Hib) conjugate vaccine.

The cross-reactive material (CRM197) of diphtheria toxin is considered to be advantageous as a carrier molecule in the formulation of a Haemophilus influenzae type b conjugate vaccine. In order to more precisely understand the function of the CRM197 in the vaccine, we have begun mapping the T-cell epitopes of the protein. A peptide which represents a segment of the primary sequence of CRM197 has been identified and found to stimulate diphtheria toxoid or CRM197-primed murine T-lymphocytes. In addition, the peptide is capable of priming T-cells in vivo for a subsequent in vitro T-cell response to itself or to the intact CRM197 molecule. The ability of the peptide to replace CRM197 as a carrier molecule was examined by immunizing mice with PRP, PRP-CRM197 conjugate, or PRP covalently coupled to the peptide. Antibodies to PRP were only detected in the PRP-CRM197 or PRP-peptide immunized groups. Both conjugates elicited primary and secondary antibody responses. Thus, a synthetic peptide representing a defined T-cell epitope of CRM197 has been functionally demonstrated based on its ability to act as a carrier molecule in a PRP conjugate vaccine.

Crystallization of Random Copolymers.

A theory of crystallization is formulated for random copolymers which crystallize with the non-crystallizable co-units incorporated into the crystalline lattice as defects. The appropriate melting point equation and other associated thermodynamic properties are derived for this model as a function of crystal thickness and comonomer concentration. The formation of lamellar type morphology is assumed to be a kinetically determined phenomena and nucleation theory is utilized accordingly. The isothermal lamella thickness is predicted to increase in a definitive manner as the noncrystallizable comonomer concentration X increases, while the associated isothermal growth rate is predicted to decrease. The variation of lamella thickness with X when the copolymer is quenched or cooled at a uniform rate is also qualitatively predicted. Under these conditions lamella thickness decreases with increasing X, which is in accord with previous experimental observations on random copolymers of tetrafluoroethylene and hexafluoropropylene as well as other random copolymers. Theory also suggests how the surface free energy parameters σ e and σ can be determined from isothermal crystallization experiments for a series of random copolymers of varying composition.

Effect of Low Pressures on the Room Temperature Transitions of Polytetrafluoroethylene.

Between approximately 20 and 30 °C at atmospheric pressure, polytetrafluoroethylene exhibits a phase (denoted as IV), which has not been observed in P-V-T measurements at pressures above 108 Nm-2 (1 Kilobar). Data are presented to resolve this phase in the temperature range 0 to 50 °C and the pressure range 0 to 0.686 × 108 Nm-2. The II-IV (20 °C) transition pressure increases with temperature according to the equation P = (-820 + 26.9t + 0.68t 2) × 105 and the IV-I (30 °C) transition according to the equation P = (- 91-57.8t + 1.99t 2) × 105 suggesting a possible triple point near 2.6 × 108 Nm-2 and 54 °C. However, the IV-I transition probably cannot be resolved by volume measurements at pressures above 2 × 108 Nm-2 because its volume of transition is small and the two transitions overlap. The enthalpies of the transitions are calculated for different pressures and some thermodynamic properties of phase IV are determined indirectly. It is shown that, if the effect of volume change is subtracted, random reversals of the hand of the helical conformation of the molecule can account for appreciable fractions of the enthalpy and corresponding entropy change for the combined transitions at atmospheric pressure.