Diagnosis of gastritis caused by Helicobacter pylori in children by means of an ELISA.

In this study, the systemic immune response to bacterial cell sonicates of Helicobacter pylori was characterized in children with symptomatic gastroduodenal disease. Isotype-specific antibodies to H. pylori in samples of serum from 16 children with culture-proven disease caused by H. pylori and from 19 controls with negative cultures were measured by ELISA with bacterial cell lysates. The levels in serum of IgA antibody to cell sonicates of H. pylori were significantly higher in the patients with positive cultures than in the controls. Only 45% of patients were infected when the established optical density cutoff was used to discriminate between patients infected and not infected with H. pylori. Levels of IgM antibody in serum were not significantly higher in patients who were infected with H. pylori. On the basis of this survey and of previous work conducted in our laboratory, we conclude that at a serum dilution of 1:800, IgG but not IgA or IgM antibody to H. pylori is useful in the rapid screening of symptomatic children for the presence of H. pylori.

Campylobacter pylori: a new pathogen.

There is now considerable evidence suggesting that C. pylori is a human pathogen. The strong association between C. pylori and gastroduodenal disease is well documented. A number of hypotheses have been suggested for the pathogenic mechanisms of C. pylori-induced gastroduodenal disease, including the production of cytotoxins and the mechanical disruption of the epithelium. At the present time, treatment with a combination of antimicrobial agents eradicates the infection in approximately 50% of cases. Until an ideal therapeutic regimen is available, antimicrobial therapy is recommended only for those patients who continue to be symptomatic following 6 to 8 weeks of treatment with an H2-receptor.

Effects of topical anesthetic agents on Campylobacter pylori.

The susceptibility of Campylobacter pylori was determined for the two topical anesthetic agents commonly used prior to gastroscopy. Campylobacter pylori proved to be extremely sensitive to the anti-infective activity of benzocaine, the active ingredient in most commonly used topical anesthetic agents, with minimum inhibitory concentrations of 0.14 mg/ml. However, lidocaine-containing agents did not interfere with the growth of this microorganism. Specifically, in patients with histologic evidence of C. pylori, the bacterium was recovered from significantly more patients anesthetized with lidocaine than with benzocaine. Thus, the use of benzocaine-containing topical anesthetic agents limits recovery of Campylobacter pylori from clinical specimens and might account for the low colonization rates reported in some recent publications.

Rapid clearance of a structural isomer of bilirubin during phototherapy.

During phototherapy for neonatal jaundice, bilirubin is converted into a variety of photoproducts. Determination of the relative importance of these photoproducts to the elimination of bilirubin requires knowledge of their rates of excretion. We have measured the rate at which the structural isomer of bilirubin, lumirubin, disappeared from the serum of nine jaundiced premature infants after the cessation of phototherapy. In all patients studied, the decline in serum lumirubin could be approximated by a first-order rate equation with a half-life of 80 to 158 min. This rate of disappearance is much faster than that previously determined for the other major bilirubin photoproducts. In samples of bile aspirated from the duodenum of infants undergoing phototherapy, lumirubin was the principal bilirubin photoproduct found. These results indicate that formation and excretion of lumirubin is an important route for bilirubin elimination during phototherapy.

Effect of spectral distribution on isomerization of bilirubin in vivo.

The purpose of our study was to compare the effects of narrow-spectrum blue light and broad-spectrum white light on the production of bilirubin photo-isomers in human infants with jaundice. Twelve preterm infants were studied under both white and blue light. Irradiance at 450 nm was controlled at 12 microW/cm2/nm for both light sources. Each light condition (white or blue) was administered for 12 hours. Bilirubin isomers (4Z,15E-bilirubin and lumirubin) were measured before therapy and after 12 hours of each sequential light condition. The percentage of 4Z,15E-bilirubin was greater under blue light than under white light (P less than 0.01) phototherapy. There was no significant difference in percentage lumirubin under white or blue light therapy. Our data indicate that blue light is more effective than white light in producing 4Z,15E-bilirubin in vivo. Our study demonstrates that when irradiance in the bilirubin absorbance spectrum is constant, the color of light (spectral distribution) will determine the relative concentrations of photo-isomers produced.

Bilirubin photoisomerization in premature neonates under low- and high-dose phototherapy.

Photoisomerization of native bilirubin to more polar configurational isomers (Z,E-bilirubin) and structural isomers (lumirubin) was studied in 20 premature infants with physiologic jaundice to determine the effect of low-dose (6 microW/cm2/nm) v high-dose (12 microW/cm2/nm) phototherapy. Patients were assigned prospectively to receive either low- or high-dose treatment. Study groups were comparable with regard to birth weight, gestational age, and total bilirubin prior to the initiation of phototherapy. Treatment was administered with white light produced by a commercially available halogen-tungsten lamp. Dose was measured periodically during the study to ensure a uniform distribution of irradiance and constant exposure. Sera for photoisomers were obtained before initiation of treatment and at two, four, and eight hours. Photoisomers expressed as a percent of total bilirubin were determined using high-pressure liquid chromatography. Serum proportion of both configurational and structural isomers increased with the duration of phototherapy in both treatment groups. There was no significant difference between the percent of configurational isomers in low- and high-dose phototherapy groups. However, high-dose treatment produced a significantly higher proportion of the structural isomer lumirubin after four hours (0.7% low dose v 1.3% high dose, P less than .05). These data confirm that phototherapy results in both configurational and structural isomerization of bilirubin in vivo. Furthermore, the previously described "dose" effect of phototherapy may be attributed to the production of the structural isomer, lumirubin.

Epidermal enzyme-mediated mutagenicity of the skin carcinogen, 2-aminoanthracene.

Using four Salmonella typhimurium tester strains (TA1537, TA1538, TA98 and TA100) and the promutagen 2-aminoanthracene, an epidermal S9-mediated mutagenicity assay was developed. Using an activation mixture derived from whole skin of the rat, mutagenicity was observed in tester strain TA98 whereas an activation mixture derived from the dermis resulted in mutagenicity in tester strains TA1538, TA98 and TA100. Activation mixtures from both the epidermis and the liver produced a positive response in all of the tester strains studied. Activation mixtures from liver were shown to have the highest specific activity followed in decreasing order of potency by epidermis, dermis and whole skin. These results indicate that the skin, a target tissue directly exposed to environmental chemicals, is capable of converting 2-aminoanthracene to mutagenic moieties. Since the skin of the rat is known to be susceptible to tumor induction by 2-aminoanthracene our findings re-emphasize that membrane-bound enzymes can influence toxic responses including mutagenicity to xenobiotics in cutaneous tissue.

Urinary excretion of an isomer of bilirubin during phototherapy.

Lumirubin, a water-soluble photoproduct of bilirubin formed in vivo during phototherapy, is excreted in the urine. In premature infants with little or no bilirubin conjugating activity, lumirubin is the principal yellow pigment found in the urine during phototherapy. The clearance rate of lumirubin in nine premature infants varied from 0.05 to 0.65 ml/min and increased with postconceptional age in parallel with increased creatinine clearance rate. The amount of lumirubin excreted per 24 h was estimated to be from 0.2 to 9.4 mg with a mean of 3.2 mg. The urinary excretion of lumirubin is a significant pathway for pigment elimination during phototherapy.

Phototherapy for neonatal jaundice: in vivo clearance of bilirubin photoproducts.

Phototherapy results in the conversion of native bilirubin to more water-soluble configurational and structural isomers. The serum half-life for the configurational isomer, the principal photoproduct in vivo, was determined by high pressure liquid chromatography in six premature infants following cessation of phototherapy. The mean half-life for this isomer was 15 h. The excretion of this isomer, calculated from the measured half-life, is less than half of daily bilirubin production, and therefore cannot account for the total bilirubin elimination observed during phototherapy. The serum concentration of the structural isomer, lumirubin, is lower than that of the configurational isomer; however, excretion is more rapid (serum half-life less than 2 h). Because of its rapid excretion, lumirubin may be an important pathway for bilirubin elimination during phototherapy.

Niridazole: Evidence for promutagenic events involving guanine-cytosine and adenine-thymine base pairs.

Niridazole, a widely used antiprotozoan agent, is mutagenic for Salmonella typhimurium strains that contain guanine-cytosine as well as adenine-thymine base pairs at their mutational sites. The mutagenic activity for both types of targets depends upon nitroreduction.

Phototherapy for neonatal jaundice: in vitro comparison of light sources.

Phototherapy results in the conversion of bilirubin to more water-soluble isomers. Six clinically used phototherapy lamps which differ in their emission spectra have been compared in their ability to produce configurational and structural isomers of bilirubin in vitro. For all of the lamps, the initial rate of configurational isomerization was highly correlated (r = 0.969) with the intensity of irradiation falling within the bilirubin absorption band. The percentage of the total bilirubin converted to the configurational isomer at equilibrium was dependent upon the spectral distribution of the lamp, and was greatest (26.2 +/- 1.3%) with the special blue lamp, which has a narrow spectral output centered at 445 nm. The rate of formation of the structural isomer, lumirubin, was generally dependent upon the intensity of irradiation within the bilirubin absorption band.

Actinobacillus actinomycetemcomitans endophthalmitis with subacute endocarditis.

Endocarditis and unilateral endophthalmitis due to Actinobacillus actinomycetemcomitans heart disease. The ocular infection was notable for its localized presentation and slow evolution. Treatment with systemic, subconjunctival, and topical gentamicin sulfate and ampicillin sodium achieved 20/20 acuity with a residual chorioretinal scar in the nasal periphery. Intravitreal injection of the organism into a rabbit confirmed its minimal pathogenicity within the eye. This organism must now be considered in patients with differential diagnosis of endogenous endophthalmitis complicating endocarditis and septicemia.

Phototherapy for neonatal jaundice: optimal wavelengths of light.

Phototherapy results in transformation of bilirubin to more water-soluble isomers. The efficacy of monochromatic visible light from 350 to 550 nm in the fastest photoisomerization reaction was quantitated by high-pressure liquid chromatography. The most effective wavelengths in vitro (i.e., leading to greater than 25% photoisomer) were in the blue spectrum from approximately 390 to 470 nm. Green light (530 nm) was not only ineffective for production of photoisomer, but capable of reversing the reaction. The results indicate that any clinically useful phototherapy unit must include the blue portion of the visible spectrum, and suggest that the effectiveness of phototherapy may be increased by elimination of green light.

Susceptibility of penicillin-resistant pneumococci to eighteen antimicrobials: implications for treatment of meningitis.

The minimal inhibitory concentrations (MICs) of 18 antibiotics including 16 beta-lactam antibiotics were determined by agar dilution on 70 strains of pneumococci (25 penicillin sensitive, 18 intermediate resistant and 27 resistant). The antimicrobials tested were penicillin G, ampicillin, carbenicillin, ticarcillin, piperacillin, mezlocillin, cephalothin, cefoxitin, cefamandole, latamoxef (moxalactam), cefotaxime, cefoperazone, ceftazidime, ceftriaxone, N-formimidoyl thienamycin, SCH 29482, chloramphenicol and vancomycin. Of these agents, only cefotaxime demonstrated greater activity than penicillin against intermediate penicillin-resistant strains while cefoperazone, ceftriaxone, N-formimidoyl thienamycin and vancomycin as well as cefotaxime demonstrated activity superior to penicillin against penicillin-resistant strains. Comparison of the MIC90s of these agents with the achievable cerebrospinal fluid levels suggests that meningitis caused by penicillin-resistant pneumococci should respond to treatment with cefotaxime, cefoperazone, ceftriaxone and vancomycin.

Short communication. Photochemical reactions of riboflavin: covalent binding to DNA and to poly (dA) . poly (dT).

Standard phototherapy illumination of human cells in the presence of riboflavin is known to produce single-strand breaks in intracellular DNA. A new photochemical reaction is described between riboflavin and purified DNA in which an adduct is formed. Unlike the previously described oxygen-dependent reaction between light-activated riboflavin and deoxyguanosine, this new photochemical reaction is oxygen-independent and involves deoxyadenosine or thymidine.

Potential for genetic damage from multivitamin solutions exposed to phototherapy illumination.

The ability of standard phototherapy illumination to produce damage in intracellular DNA is well established. In this study, the addition of a dilute solution (1:6400) of a clinically-used multivitamin concentrate to human KB cells was found to enhance the generation of single-strand DNA breaks produced by broad-spectrum fluorescent light. The effect of the exogenous photosensitizing agent (multivitamins) was blocked by the enzyme catalase; thus, the photoproduct responsible for the DNA modification was hydrogen peroxide, an extremely reactive molecule capable of damaging a variety of biologic macromolecules.