Fluorescent supramolecular hierarchical self-assemblies from glycosylated 4-amino- and 4-bromo-1,8-naphthalimides

The investigation into the self-assembly formation of the glycan based 4-amino- and 4-bromo-1,8-naphthalimide (Nap) structures1–3is presented.

The 13C-xylose breath test for the diagnosis of small bowel bacterial overgrowth in children

BACKGROUND

We evaluated the clinical utility of the 13C-xylose breath test for the diagnosis of small bowel bacterial overgrowth in children.

METHODS

To determine the optimal dose of 13C-xylose, 29 healthy children, 3 to 12 years old, were randomly assigned to receive one of three doses of 13C-xylose (10, 25, or 50 mg). After an overnight fast, the oral dose of 13C-xylose was administered, and breath samples were collected every 30 minutes for 4 hours. Samples were analyzed for 13CO2 by gas chromatography with mass spectrometry. Using the 50 mg dose, we then performed nine breath tests with concurrent duodenal bacterial cultures in 6 children, 3 to 12 years old, with short-bowel syndrome (n = 2), immunodeficiency states (n = 1), and motility disorders (n = 3).

RESULTS

Excretion of 13CO2 in breath peaked at 2.5 hours in all three control groups. The 50-mg dose produced the highest median peak and the smallest range of 13CO2 excretion in breath within each time period. The time of peak 13CO2 excretion in breath varied among the diseased children; however, the six patients with small-bowel bacterial overgrowth (2 x 10(5)-3.5 x 10(5) gram negative rods) all had peak 13CO2 that exceeded the maximum breath 13CO2 level in breath of the control subjects at the corresponding time period (100% sensitivity). Of the three patients with negative cultures, two had negative breath test results and one had positive results (67% specificity). One subject had normalization of both duodenal culture and breath test results after antibiotic treatment of small-bowel bacterial overgrowth.

CONCLUSIONS

Our preliminary results suggest that with a dose of 50 mg 13C-xylose, breath test results reliably predict small-bowel bacterial overgrowth in susceptible children.

Freedom from transmission of hepatitis-B of gamma-globulin and heat-inactivated plasma protein fraction prepared from contaminated human plasma by fractionation with solid-phase polyelectrolytes

Plasma contaminated with hepatitis B surface antigen (HBsAg) and shown by others to be infectious when injected in a dilution of 1:1,000,000 in chimpanzees, was fractionated by a solid-phase polyelectrolyte (PE) procedure for its content of plasma protein fraction (PPF) and gamma-globulin (immune serum globulin; ISG). Quantitative Ausria II radioimmunoassays showed that nearly half the HBsAg was bound by the PE and could be eluted at low pH, while the rest was found in the heat-inactivated PPF. When the ISG was concentrated to 16%, the 13 mg/kg (comparable to a human dose) was injected intramuscularly in 6 chimpanzees, or when the PPF was heated at 60 degrees C for h and injected intravenously in 2 chimpanzees, there was no clinical or laboratory evidence of hepatitis B infection after 12 months, although 1 chimp of 2 who received the same material showed a borderline positive anti-HBsAg antibody result on one of 52 weekly serum samples. Since the new PE fractionation method is essentially nondenaturing, and simpler than the classical ethanol procedures, it was important to establish the noninfectivity of the final products.

Intracellular proteases of Bacillus stearothermophilus

Cell-free extracts of Bacillus stearothermophilus have been shown to exhibit proteolytic activity toward casein as well as specific activity to catalyze the hydrolysis of furylacryloylglycyl-l-leucine amide, furylacryloylglycine, and carbobenzoxyl-glycine-p-nitrophenyl ester, indicating the presence of a neutral proteinase, a carboxypeptidase-like enzyme, and an alkaline proteinase. The neutral proteinase and carboxypeptidase-like activities were separated by gel filtration over Bio-Gel P-60, and both were reversibly inhibited by 1, 10-phenanthroline. The esterase activity was inhibited by diisopropylfluorophosphate, which did not affect other enzymatic activities and was insensitive to 1, 10-phenanthroline and ethylenediaminetetra-acetic acid.