Severe delayed-onset hypersensitivity reactions to amoxicillin in children.

Amoxicillin, a semisynthetic aminopenicillin, has achieved widespread use in recent years for the treatment of respiratory tract and otic infections. Serious reactions have been relatively infrequent. From July 1986 to June 1987, 11 children aged 6 months to 10 years presented with delayed-onset hypersensitivity reactions. In 10 the symptoms were consistent with a serum-sickness-like illness, including urticaria, angioedema, arthritis and arthralgia. Radioallergosorbent testing for IgE antibodies to penicillin yielded negative results, and lymphocyte transformation testing gave a positive result in only one patient. Because of the negative immunologic test results and the occurrence of reactions only in children, who had received an amoxicillin solution, the reactions may have been caused by the excipient.     

Anti-IgA-mediated transfusion reactions in Canada.

During a 6-year period (1977 to 1982) blood samples from 152 Canadian patients were referred to the national reference laboratory of the Canadian Red Cross Society because the referring hospitals had not been able to determine the cause of the patients'' severe nonhemolytic transfusion reactions. Twenty-one patients were found to be IgA deficient, and 12 of them had strong class-specific anti-IgA antibodies, which were presumed to have been responsible for the reactions. The spectrum of symptoms that accompanied these violent reactions was documented for 10 of the patients. As a probable minimum, the incidence of anti-IgA-mediated reactions averaged 1.3 per million units of blood or blood products transfused during this period.     

Novel carbon-carbon bond formations for biocatalysis

Carbon-carbon bond formation is the key transformation in organic synthesis to set up the carbon backbone of organic molecules. However, only a limited number of enzymatic C-C bond forming reactions have been applied in biocatalytic organic synthesis. Recently, further name reactions have been accomplished for the first time employing enzymes on a preparative scale, for instance the Stetter and Pictet-Spengler reaction or oxidative C-C bond formation. Furthermore, novel enzymatic C-C bond forming reactions have been identified like benzylation of aromatics, intermolecular Diels-Alder or reductive coupling of carbon monoxide.     

Novel cofactor derivatives and cofactor-based models

In 1997 and the first half of 1998, numerous publications appeared reporting studies of cofactors and their analogues in classical model systems and in enzyme-catalyzed reactions directed at understanding the enzymatic reactions of their natural cofactors. Model systems based on flavins have provided new insights into enzymatic modulation of the flavin reduction potential, and enzymatic reactions of coenzyme A analogues and derivatives have been employed in several studies of coenzyme A utilizing enzymes. Coenzyme B₁₂ analogues have been utilized as alternate cofactors for B₁₂-utilizing enzymes, while pyrroloquinoline quinone esters and analogues have been employed in model studies of the reactions of quinoprotein-catalyzed reactions.     

Kinetic studies of mobilization of copper(II) from human serum albumin with chelating agents

The kinetics of the mobilizing reactions of five chelating agents for human serum albumin (HSA)-bound copper(II) [Cu(II)] have been studied spectrophotometrically. The decreasing sequence of reaction rate has been determined to be EDTA greater than DTPA greater than EGTA greater than NTA greater than IDA. A group of mathematical models were established to define the mechanisms of the competitive reactions between low-molecular-weight ligand and macromolecular ligand. All reactions of the five chelating agents follow a process involving the intermediate ternary complexes: (formula; see text) The reactions of DTPA and EDTA were found to be different from those of EGTA, NTA, and IDA. In the former cases, the reactions are likely following an overlapping mechanism in which the rate constant k1 was closed to k2. The reactions involving the other three chelators are different in k1 much greater than k2.     

Condensation reaction of hexanucleotides containing guanine and cytosine with water soluble carbodiimide.

The condensation reactions of hexanucleotides involving guanine and cytosine in the presence of water-soluble carbodiimide (WSC) have been investigated as a model reaction of the prebiotic formation of RNA under primitive earth. The reactions formed cyclic hexanucleotides and dimers in which the product yields were dependent on the sequence.     

An ab initio computational study of thiamin synthesis from gaseous reactants of the interstellar medium

A set of chemical reactions is proposed to account for the formation of thiamin derivatives from gaseous reactants that have been identified in the interstellar medium, and may have been relevant to a prebiotic atmosphere. The gaseous mixture consisted of methanimine, acetonitrile, cyanoacetylene, ammonia, acetylene, allylene, hydrogen sulfide, thioformaldehyde, and hydrogen in the presence of water. Most of the reactions appear to be exothermic. The reactions have been shown to be feasible from the overall enthalpy changes in the ZKE approximation at the HF and MP2/6-31G(*) level.     

Stereospecific synthesis of beta-D-allopyranosides by dihydroxylation of beta-D-erythro-2,3-dideoxyhex-2-enopyranosides

The synthesis of 4,6-O-benzylidene-beta-D-erythro-2-3-dideoxyhex-2-enopyranosides and their osmium and ruthenium catalysed dihydroxylation reactions have been investigated. These reactions have been shown, for a range of monosaccharides and a disaccharide, to proceed stereospecifically to give beta-D-allopyranosides in moderate to excellent yield.     

A Pharmacovigilance Approach for Post-Marketing in Japan Using the Japanese Adverse Drug Event Report (JADER) Database and Association Analysis

BackgroundRapid dissemination of information regarding adverse drug reactions is a key aspect for improving pharmacovigilance. There is a possibility that unknown adverse drug reactions will become apparent through post-marketing administration. Currently, although there have been studies evaluating the relationships between a drug and adverse drug reactions using the JADER database which collects reported spontaneous adverse drug reactions, an efficient approach to assess the association between adverse drug reactions of drugs with the same indications as well as the influence of demographics (e.g. gender) has not been proposed.ConclusionsDifferent combinations of adverse drug reactions were noted between the antidepressants. In addition, the reported adverse drug reactions differed by gender. This approach using a large database for examining the associations can improve safety monitoring during the post-marketing phase.     

Synthesis and structure--activity relationship of novel aminotetralin derivatives with high micro selective opioid affinity

Several novel racemic aminotetralin derivatives have been prepared using a stereoselective aziridine ring opening reactions and were evaluated for their micro-opioid receptor binding affinity. Selectivity index towards other opioid receptors and antinociceptive activity in mice have been evaluated for the most potent derivatives.     

The properties of precipitation reactions between secretion products in the oviduct of pleurodeles: identification of a lectin

The properties of two precipitation reactions occurring between secretory products from the oviduct of Pleurodeles waltl have been studied. It has been demonstrated that a lectin is involved in one of the reactions. This lectin precipitated glycogen and starch and required calcium; the most potent saccharide inhibitors were 2-amino-2-deoxy-D-glucose and D-glucose, respectively. The other reaction was related to glycoproteins (probably sulfated glycoproteins) that contained sulphur. The properties of this reaction were not the same as purely ionic interactions; basic protein-acidic polysaccharide interactions have been compared. A lectin was probably implicated but this could not be demonstrated because no saccharide inhibitor was found. There are several similitudes between this reaction and the lectin-galactoside reaction which occurs in the reaction between cortical granule content and egg jellies in anurans.     

Antibiotics--cloning of biosynthetic pathways

Biosynthetic pathways leading to antibiotics have often been found to be clustered, and new organizational forms of multifunctional enzymes have been discovered. Such polyenzymes accomplish the synthesis of complex metabolites such as peptides or polyketides by a sequence of enzymatic reactions. So, reactions leading to the tripeptide precursor of beta-lactam antibiotics, ACV, or to the cycloundecapeptide cyclosporine have been fused into single polypeptide chain synthetases, respectively. In certain isofunctional sites restricted similarities have been detected.     

Oscillatory reaction of alcohol dehydrogenase in an oil/water system

With the use of an oil/water system, oscillatory reactions of an enzyme have been demonstrated. This reaction system has been conceived as an example of the metabolic oscillations of living cells. When a substrate (ethanol) in the oil phase of toluene or chloroform slowly migrated into the aqueous phase containing alcohol dehydrogenase and NAD+, oscillations were observed in the concentration of NADH produced. The gradual entry of substrate into the aqueous phase was essential for the oscillatory reactions to occur. A possible mechanism to account for the appearance of oscillatory reactions of enzymes is proposed, which differs from that presented previously.     

Characterization of Ornithine Decarboxylase-Positive, Nonmotile Strains of the Klebsiella-Enterobacter Group

Thirty-seven strains of ornithine decarboxylase-positive, nonmotile Klebsiella-Enterobacter organisms isolated from 36 patients were studied by biochemical and serological testing. Five strains gave biochemical reactions which conformed closely to those of Escherichia coli; three strains gave positive Quellung reactions to specific Klebsiella antisera. (Two of these were thought to be Enterobacter in spite of this typing reaction.) The remaining 29 strains were classified as Enterobacter. These results demonstrate the necessity of doing both an ornithine decarboxylase test and a motility test to differentiate Klebsiella from Enterobacter. Had only a motility test been done, they all would have been called Klebsiella.     

The interaction of adrenochrome with some thiol-containing amino acids isolation of some products

The interactions of adrenochrome with some thiol-containing amino acid derivatives, namely, N-acetylcysteine and N-acetylpenicillamine, have been studied. The 5,6-dihydroxy-1-methylindole thioethers which were formed in these reactions were isolated and characterized. The structures of these products were analogous to those of similar compounds which had been obtained from the reactions of aminochromes with some simple thiols. Reactions of this type may be important in the formation of melanoproteins.     

Responses of cattle to allergens from Boophilus microplus

Extracts of larvae of the cattle tick, Boophilus microplus, contain two allergens giving immediate hypersensitivity reactions in the skin of cattle which have been exposed to the tick. The partial purification of one of these is described. This, together with the other allergen whose purification has been described previously, was used to investigate the relationships between tick resistance, immediate hypersensitivity reactions, reaginic antibody levels as measured by Prausnitz-Küstner type reactions and serum levels of agglutinating antibody to one of the allergens. There were significant correlations between resistance and both the immediate hypersensitivity reactions and agglutinating antibody levels.     

The histochemistry of complex carbohydrates in the epithelium lining the ventral prostate of the rat

Summary In the epithelium lining the ventral prostate of the rat, complex carbohydrate-containing structures have been studied by means of both light and electron microscopic histochemical methods. According to light microscopy, the free surface and granules of different sizes in the distal cytoplasm of the epithelial cells were found to exhibit positive reactions for complex carbohydrates with 1,2-glycol and acidic groups and sialic acid residues. In addition, secretory substances within the glandular lumen were shown to exhibit positive reactions for similar groups and saccharide residues of complex carbohydrates. In electron microscopy, the surface coat of the plasma membrane, certain elements of the Golgi apparatus and lysosomal dense bodies were found to exhibit positive reactions for glycoproteins with 1,2-glycol groupings. The histophysiological significances of the carbohydrate-containing structures have been discussed with special reference to the known physiological functions of the prostate in the rat.     

3-Nitropyrrole and 5-nitroindole as universal bases in primers for DNA sequencing and PCR.

3-Nitropyrrole and 5-nitroindole have been assessed as universal bases in primers for dideoxy DNA sequencing and in the polymerase chain reaction (PCR). In contrast to a previous report, we have found that the introduction of more than one 3-nitropyrrole residue at dispersed positions into primers significantly reduced their efficiency in PCR and sequencing reactions. Primers containing 5-nitroindole at multiple dispersed positions were similarly affected; for both bases only a small number of substitutions were tolerated. In PCR experiments neither base, when incorporated into primers in codon third positions, was as effective as hypoxanthine, which was incorporated in six codon third positions in a 20mer oligomer. However, primers containing up to four consecutive 5-nitroindole substitutions performed well in both PCR and sequencing reactions. Consecutive 3-nitropyrrole substitutions were tolerated, but less well in comparable reactions.     

Characteristics of the vascular reactions of rabbits to prolonged stimulations in experimental atherosclerosis

The constrictory reactions to long electrostimulation of renal, pulmonary femoral arteries and distal aorta segments of intact rabbits getting 200 mg/kg of holesterine during 4-12 months have been compared. It has been established that all artherosclerotic vessels exhibit higher initial amplitude of constriction using as indicator of phasic reactions. the tetanus stability increases, that expresses in longer conservation of initial constriction amplitude on relatively high level; this is evidence of vessels capacity to long tonic reactions. These changes of aorta and pulmonary vessels were more distinct.     

The disequilibrium pH: a tool for the localization of carbonic anhydrase

The disequilibrium pH is defined as any discrepancy between the measured pH and the pH which would exist if CO2-HCO3-H+ reactions were at equilibrium. Measurement of the disequilibrium pH can be used to assess the status of CO2-HCO3--H+ reactions and, in combination with carbonic anhydrase (CA) or CA inhibitor treatments, may also be used to localize CA. Renal physiologists have used disequilibrium experiments to determine that HCO3- reabsorption in the kidney tubule occurs via proton secretion, and that CA activity is available to ultrafiltrate CO2-HCO3-H+ reactions in the proximal convoluted tubule, but not the distal tubule. Disequilibrium experiments were also used in investigating the availability of CA to CO2-HCO3--H+ reactions in water at the fish gill; the opposing results obtained in two studies have not yet been resolved. Respiratory physiologists have used the disequilibrium technique in vivo and with saline-perfused preparations to assess the availability of CA to plasma CO2-HCO3--H+ reactions following gas exchange. Saline-perfused preparations enable direct localization of CA activity, while in vivo measurements encompass the numerous factors affecting CO2-HCO3--H+ equilibration in a multi-phase solution. Given the many organs in which membrane-bound CA activity has now been identified, the usefulness of the disequilibrium pH technique has increased beyond its original applications in renal and pulmonary physiology.