Treatment of cyclic vomiting in childhood with erythromycin

Cyclic vomiting syndrome is an unusual cause of episodic emesis in children. It manifests as intermittent episodes of severe vomiting, similar in time of onset and duration, with no symptoms during the intervening period. Dehydration necessitating intravenous fluid therapy may occur. Most therapeutic maneuvers have proven unsuccessful. We report the use of erythromycin as a prokinetic agent in the treatment of cyclic vomiting in 20 children (9 boys, 11 girls). Many patients had mild associated abdominal pain with their vomiting. Thirteen patients had previously been given metoclopramide, but none responded. Two patients were mildly developmentally delayed. Twenty patients were given oral erythromycin ethylsuccinate, approximately 20 mg/kg/day, in 2-4 divided doses for 7 days. This dosage was repeated as needed when symptoms reappeared. Thirteen of 20 patients reported total resolution of symptoms when reevaluated at 2 and 6 months. All males responded, 4 of 13 responders were female, and all seven with partial or no response to therapy were female. This uncontrolled trial suggests that erythromycin may be a useful prokinetic agent in the treatment of cyclic vomiting syndrome in childhood. As the study was uncontrolled, placebo effect cannot be excluded. Case-controlled, double-blinded prospective trials should be considered to evaluate the effectiveness of erythromycin in cyclic vomiting syndrome.

Specific and sensitive measurement of FK506 and its metabolites in blood and urine of liver-graft recipients

A specific and sensitive assay for quantifying the immunosuppressant FK506 and its metabolites in blood and urine was developed. 32-O-Acetyl FK506 was synthesized and used as internal standard. FK506 and its metabolites were purified from the samples by solid-liquid extraction and were injected into a high-performance liquid chromatographic (HPLC) system linked to a mass spectrometer (MS) by particle-beam interface. The FK506 derivatives were separated from interfering material by use of a 100 x 4 mm C8 analytical column and water/acetonitrile or water/methanol gradient elution; they were detected by negative chemical ionization with methane as reagent gas. The limit of detection was 25 pg in a standard solution, and the limit of quantification in blood was 250 pg (extracted from 1 mL of blood). The CV was 11.3% at 5 ng, and no interferences with other drugs were found.

Specific and Sensitive Measurement of FK506 and Its Metabolites in Blood and Urine of Liver-Graft Recipients

A specific and sensitive assay for quantifying the immunosuppressant FK506 and its metabolites in blood and urine was developed. 32-O-Acetyl FK506 was synthesized and used as internal standard. FK506 and its metabolites were purified from the samples by solid-liquid extraction and were injected into a high-performance liquid chromatographic (HPLC) system linked to a mass spectrometer (MS) by particle-beam interface. The FK506 derivatives were separated from interfering material by use of a 100 x 4 mm C8 analytical column and water/acetonitrile or water/methanol gradient elution; they were detected by negative chemical ionization with methane as reagent gas. The limit of detection was 25 pg in a standard solution, and the limit of quantification in blood was 250 pg (extracted from 1 mL of blood). The CV was 11.3% at 5 ng, and no interferences with other drugs were found.

Sensitive detection of RNAs in single cells by flow cytometry

A rapid and sensitive fluorescent in situ hybridization method has been developed to probe RNA contents of individual cells by flow cytometry. Fixed cells in suspension were hybridized with 5' end-fluorophore-labeled oligodeoxynucleotides complementary to defined regions of the RNA of interest and analyzed by flow cytometry. With this method, we monitored combinations of histone H4 mRNA, 18S rRNA and 28S rRNA levels in synchronized HeLa S3 cells by multicolor analysis. A fluorescence signal equivalent to 1800 copies of histone H4 mRNA per cell was detected with signal-to-background ratio of 5.4. If non-specific binding of the fluorophore-labeled probe can be reduced, as few as 100 copies of mRNA of the size of H4 could be detected in individual cells by flow cytometry.

A unique immune response control locus mapping with the H-2D class I region

The immune response to the polysaccharide antigen Trinitrophenyl (TNP)-ficoll is controlled by two complementing loci in the murine major histocompatibility complex. One locus of control is present in the I-A subregion and the second is located between the S and D regions. A monoclonal antibody 48-21.7 was selected for its ability to significantly block the in vitro primary response to TNP-ficoll. This antibody bound to antigen-presenting cells does not interfere with the presentation of other antigens. Experiments are presented to demonstrate that the monoclonal antibody 48-21.7 precipitates a unique protein of approximately 40,000 daltons. Sequential immunoprecipitation with monoclonal antibodies to the class I Db antigen and to relevant Ia antigens demonstrated no cross-reactivity. Amino acid sequencing has found unique amino acids to be present at three class I N-terminal invariant positions. These observations indicate the presence of a unique class I-like molecule coded for by genes mapping between S and D and involved in the response to the polysaccharide ficoll.

Extracellular metal-free corrinoids from Rhodopseudomonas spheroides

Rhodopseudomonas spheroides when grown on a medium deficient of cobalt excretes significant amounts of descobaltocorrinoids into the culture broth. If grown in the presence of 4 microM CoCl2 only intracellular cobalt-containing corrinoids are detected. The extracellular corrinoids have been identified as hydrogenobyrinic acid c-amide and hydrogenobyrinic acid a,c-diamide which are accompanied by varying amounts of the corresponding 13-epicorrinoids. The latter, which could not be separated in the metal-free form, are artifacts arising from the excreted descobaltocorrinoids under the alkaline conditions of the culture broth. The red metal-free corrinoids have been converted into the corresponding cobalt-containing corrinoids and were characterized by their CD, UV, 1H NMR, and 13C NMR spectra. Insertion of cobalt into the fraction of hydrogenobyrinic acid c-amide has yielded small amounts of a cobalt-containing corrinoid, for which the structure of 18,19-didehydrocobyrinic acid c-amide is suggested. A 14C-labeled specimen of hydrogenobyrinic acid a,c-diamide was obtained by feeding [14C]acetate to growing cultures of R. spheroides. Experiments with broken cell systems of Propionibacterium shermanii and R. spheroides have indicated that metal-free corrinoids are not precursors of the cobamides. The results are discussed with respect to the final steps of the biosynthesis of vitamin B12.

The Conformational Equilibrium of 1,2,3-Tribromopropane in Solution

The p.m.r. spectra of dilute solutions of 1,2,3-tribromopropane in carbon tetrachloride, acetonitrile, and dimethylsulfoxide as well as of the neat compound are examined. From the three- and four-bond spin–spin coupling constants and from a comparison between observed and calculated dipole moments it is concluded that in nonpolar solvents the title compound exists preferably in the enantiomeric conformations a and i. In polar solvents other rotamers contribute to the equilibrium but still seem to play only a minor role. Semiempirical calculations of conformational energies rule out contributions to the conformational equilibrium from rotamers having (1:3) bromine–bromine interactions, but otherwise are only in moderate agreement with experiment.

Long-range Spin–Spin Coupling Constants from Amino Protons and 15N to Ring Protons in Aniline-15N and Some Derivatives. INDO Molecular Orbital Calculations

A complete analysis (8-spins) is given of the p.m.r. spectrum of aniline-15N, of the spectra of some haloanilines-15N and of 2-aminoacetophenone-15N. Intermolecular exchange of the amino protons is slow enough for observation of their spin–spin coupling to the ring protons. The magnitudes of the coupling constants between amino protons and 15N or ring protons are a measure of the geometry of the amino group. This is not true of the couplings between 15N and the ring protons. Long-range couplings computed in the CNDO/2 and INDO approximations of molecular orbital theory show points of agreement with experiment. For example, their signs and magnitudes are consistent with a nonplanar but not with a planar conformation of aniline. Couplings from 15N to ring protons are also computed for nitrobenzene.

Proton Magnetic Resonance Spectrum of 1-Penten-3-yne. INDO and CNDO/2 Molecular Orbital Calculations on Long-Range Spin–Spin Coupling Constants in Enynes

The high resolution p.m.r. spectra of 1-penten-3-yne in carbon disulfide and in benzene solution are analyzed. Long-range spin–spin coupling constants are discussed in terms of σ and π electron contributions. Comparisons are made with the isomeric 2-methyl-1-buten-3-yne and the parent compound, vinylacetylene. The results of INDO and CNDO/2 molecular orbital calculations are compared to the experimental coupling constants. It is concluded that the π electron contribution to 5J in enyne systems is +0.6 to 0.7 Hz and that σ electron contributions are rather small, the transoid ("pseudo-zig–zag") being larger than the cisoid one. Observed allylic coupling constants in the propene derivative are compared with the calculated values, including those for propene and 2-cyanopropene, available in the literature.