Sulfate-reducing bacteria slow intestinal transit in a bismuth-reversible fashion in mice.

BACKGROUND: Hydrogen sulfide (H2 S) serves as a mammalian cell-derived gaseous neurotransmitter. The intestines are exposed to a second source of this gas by sulfate-reducing bacteria (SRB). Bismuth subsalicylate binds H2 S rendering it insoluble. The aim of this study was to test the hypothesis that SRB may slow intestinal transit in a bismuth-reversible fashion. METHODS: Eighty mice were randomized to five groups consisting of Live SRB, Killed SRB, SRB+Bismuth, Bismuth, and Saline. Desulfovibrio vulgaris, a common strain of SRB, was administered by gavage at the dose of 1.0 × 109 cells along with rhodamine, a fluorescent dye. Intestinal transit was measured 50 minutes after gavage by euthanizing the animals, removing the small intestine between the pyloric sphincter and the ileocecal valve and visualizing the distribution of rhodamine across the intestine using an imaging system (IVIS, Perkin-Elmer). Intestinal transit (n=50) was compared using geometric center (1=minimal movement, 100=maximal movement). H2 S concentration (n=30) was also measured when small intestinal luminal content was allowed to generate this gas. KEY RESULTS: The Live SRB group had slower intestinal transit as represented by a geometric center score of 40.2 ± 5.7 when compared to Saline: 73.6 ± 5.7, Killed SRB: 77.9 ± 6.9, SRB+Bismuth: 81.0 ± 2.0, and Bismuth: 73.3 ± 4.2 (P<.0001). Correspondingly, the Live SRB group had the highest luminal H2 S concentration of 4181.0 ± 968.0 ppb compared to 0 ± 0 ppb for the SRB+Bismuth group (P<.0001). CONCLUSIONS & INFERENCES: Live SRB slow intestinal transit in a bismuth-reversible fashion in mice. Our results demonstrate that intestinal transit is slowed by SRB and this effect could be abolished by H2 S-binding bismuth.

Inhibition of iron deficiency stress response in cucumber by rare earth elements.

We investigated the influence of the trivalent scandium (Sc), chromium (Cr), gallium (Ga), yttrium (Y) and lanthanum (La) on both the function and activity of ferric chelate reductase (FCR) in cucumber (Cucumis sativus L.) roots. Cucumber seedlings were grown for 1week in a nutrient solution without Fe or in some experiments with 10microM FeEDTA. Intact root systems were assayed for FCR activity in a medium at pH 5.0 containing 100microM FeEDTA with the ferrous chelating agent Ferrozine. Addition of 100microM concentrations of the EDTA complexes of Sc, Cr, Ga, Y and La did not inhibit FCR in Fe-deficient roots. When Fe-deficient roots were grown with 10microM LaCl(3), ScCl(3), or YCl(3) for 3days, FCR activity decreased to 23%, 15% and 1%, respectively, of the activity of Fe-deficient plants grown without trivalent metal addition. Additionally, these trivalent metals suppressed proton secretion. Growth of Fe-deficient plants with 80microM Ga(2)(SO(4))(3) decreased FCR activity to 35% of the control activity while 80microM CrEDTA did not affect FCR activity. With the addition of either FeEDTA or YCl(3), FCR activity decreased to less than 5% of the activity of the Fe-deficient control roots in 3days. Addition of FeEDTA, but not Y, resulted in recovery from Fe deficiency as indicated by increasing chlorophyll content of leaves.

Permanganate oxidation of sorbed polycyclic aromatic hydrocarbons.

The polycyclic aromatic hydrocarbons (PAH) that contaminate soils at many industrial and government sites are resistant to natural biotic and abiotic degradation processes. The recalcitrant nature of these compounds may require aggressive chemical treatment to effectively remediate these sites. This study was conducted to assess the viability of permanganate oxidative treatment as a method to reduce PAH concentration in contaminated soils. Study results demonstrated a reduction in soil sorbed concentration for a mixture of six PAHs that included anthracene, benzo(a)pyrene, chrysene, fluoranthene, phenanthrene, and pyrene by potassium permanganate (KMnO4) oxidative treatment. The greatest reduction in soil concentration was observed for benzo(a)pyrene, pyrene, phenanthrene, and anthracene at 72.1, 64.2, 56.2, and 53.8%, respectively, in 30 min at a KMnO4 concentration of 160 mM. Minimal reductions in fluoranthene and chrysene concentration were observed at 13.4 and 7.8%, respectively, under the same conditions. A relative chemical reactivity order of benzo(a)pyrene>pyrene>phenanthrene>anthracene>fluoranthene>chrysene towards permanganate ion was observed. Aromatic sextet theory was applied to the degradation results to explain the highly variable and compound-specific chemical reactivity order.

Congenital lymphocytic choriomeningitis virus infection: decade of rediscovery.

Lymphocytic choriomeningitis virus (LCMV) is an underdiagnosed fetal teratogen. This diagnosis should be considered for infants and children with unexplained hydrocephalus, micro- or macrocephaly, intracranial calcifications, chorioretinitis, and nonimmune hydrops. The immunofluorescent antibody test is the only reasonable, commercially available, screening diagnostic tool. The differential diagnosis of congenital LCMV infection includes toxoplasmosis, rubella, cytomegalovirus, herpes simplex virus, enteroviruses, human parvovirus B19 [corrected], and syphilis. The infection has also been misdiagnosed as various neurologic, ophthalmologic, and chromosomal syndromes. Further research, to determine the prevalence of this infection in human and rodent populations, and prospective studies, to delineate the clinical spectrum of congenital infection, are needed. The public and members of the medical profession should be made aware of the hazard that wild, pet, and laboratory rodents pose to pregnant women.

Respiratory syncytial virus immune globulin: decisions and costs.

A decision analysis was used to evaluate the economic effectiveness of respiratory syncytial virus immune globulin (RSVIG) prophylaxis on selected pediatric populations at risk for developing RSV bronchiolitis or all respiratory illness-related hospitalizations. We compared costs, outcomes, and cost-effectiveness of administering RSVIG to no treatment in different pediatric populations, including those at risk of developing RSV-bronchiolitis and those at risk of developing any respiratory illness-related hospitalization. We observed that if only infants at high risk of severe RSV infections received treatment with RSVIG, a calculated cost saving of about 27,000 dollars per hospitalization prevented were realized. If the Food and Drug Administration (FDA)-approved indications for RSVIG were followed, the cost to prevent one hospitalization due to RSV bronchiolitis would be over 53,000 dollars. If the aim, however, was to prevent all respiratory illness-related hospitalizations for this broader population, a much lower cost (4,000 dollars) to prevent one hospitalization would result. In this situation, cost neutrality was possible, with a therapy cost of 2,843 dollars compared to the actual average therapy cost of 4,444 dollars. Sensitivity analysis showed that the model was relatively insensitive to all variables, with the exceptions of costs related to RSVIG and intensive care unit (ICU) admissions. We conclude that RSVIG resulted in cost savings if therapy were reserved for the infants who are at highest risk for developing severe RSV infections. RSVIG is not cost-effective for preventing RSV bronchiolitis when used according to the FDA-approved indications. Education that emphasizes frequent hand-washing, avoidance of passive smoking, and lessening exposure to sick children remains the least expensive prevention tool.

The use of dietary supplements in pediatrics: a study of echinacea.

Alternative medical therapies are commonly used and have increased in popularity. Although patients may not always disclose the use of alternative therapies, they may seek advice regarding their use, especially for children. Regulation and standardization of these modalities, especially botanicals, is incomplete. The University of Arizona has initiated a study of the use of echinacea in the prevention of recurrent otitis media. A review of echinacea preparations was undertaken, and this report discusses the complexities surrounding the use of this dietary supplement. The number and diversity of echinacea preparations are detailed; the role of the physician as "botanical" advisor to patients and families is examined.

Bacteremic infection with Pediococcus: vancomycin-resistant opportunist.

Pediococci are recently recognized Gram-positive human pathogens, resistant to vancomycin and generally susceptible to penicillin. Infection in adults has been seen in patients with chronic underlying conditions as well as those with previous abdominal surgery. Two previous infants with congenital gastrointestinal malformations requiring surgical correction have been reported with sepsis attributable to Pediococcus sp. We report a third infant born with gastroschisis who developed Pediococcus bacteremia and meningitis 3 months after surgery, and speculate regarding the role of probiotics in the pathogenesis of this infection.

Coccidioidomycosis in adolescents with lupus nephritis.

Coccidioidomycosis, a fungal infection endemic in the southwestern United States, can cause life-threatening infections in immunosuppressed patients. We report the contrasting cases of two adolescents with lupus nephritis, treated with intravenous pulse cyclophosphamide and daily oral corticosteroids, who developed pulmonary coccidioidomycosis. One patient developed a fatal form of fulminant disseminated coccidioidomycosis, while the other patient developed a solitary pulmonary Coccidioides immitis abscess which was responsive to intravenous liposomal amphotericin and fluconazole therapy. Because serologies and initial X-ray studies can be negative, definitive diagnostic studies including bronchoaveolar lavage and needle aspiration should be performed when there is clinical suspicion of coccidioidomycosis in an immunocompromised patient. Immunosuppressed patients with coccidioidomycosis should receive early intravenous amphotericin therapy and may benefit from long-term suppressive antifungal therapy to prevent relapse.

Lymphocytic choriomeningitis virus: an underdiagnosed cause of congenital chorioretinitis.

PURPOSE: To elucidate the role and clinical spectrum of congenital lymphocytic choriomeningitis virus infection as a cause of chorioretinopathy, congenital hydrocephalus, and macrocephaly or microcephaly in the United States. METHODS: We performed complete ophthalmologic surveys of all residents at Misericordia, a home for the severely mentally retarded in Chicago, and prospectively evaluated all patients with chorioretinitis or chorioretinal scars during a 36-month period at Children's Memorial Hospital, also located in Chicago. Sera for patients demonstrating chorioretinal scars (a sign of intrauterine infection) were tested for Toxoplasma gondii, rubella virus, cytomegalovirus, and herpes simplex virus and lymphocytic choriomeningitis virus antibodies. RESULTS: Four of 95 patients examined at the home had chorioretinal scars, and two of these patients had normal T. gondii, rubella virus, cytomegalovirus, and herpes simplex virus titers and dramatically elevated titers for lymphocytic choriomeningitis virus. Three of 14 cases of chorioretinitis at the hospital had normal T. gondii, rubella virus, cytomegalovirus, and herpes sim-plex virus titers and elevated lymphocytic choriomeningitis virus antibody titers. (A fourth case, diagnosed in 1996, was reported 2 years ago.) CONCLUSIONS: Lymphocytic choriomeningitis virus was responsible for visual loss in two of four children secondary to chorioretinitis in a population of severely retarded children. The six new cases of lymphocytic choriomeningitis virus chorioretinitis identified in these two populations over the last 3 years, compared with the total number ever reported in the United States (10 cases), suggests that lymphocytic choriomeningitis virus may be a more common cause of congenital chorioretinitis than previously believed. Because its consequences for visual and psychomotor development are devastating, we conclude that the workup for congenital chorioretinitis should include lymphocytic choriomeningitis virus serology, especially if T. gondii, rubella virus, cytomegalovirus, and herpes simplex virus titers are negative.

Lymphocytic choriomeningitis virus: reemerging central nervous system pathogen.

Lymphocytic choriomeningitis virus (LCMV), a human zoonosis caused by a rodent-borne arenavirus, has been associated with both postnatal and intrauterine human disease. Infection in man is acquired after inhalation, ingestion, or direct contact with virus found in the urine, feces, and saliva of infected mice, hamsters, and guinea pigs. Congenital LCMV infection is a significant, often unrecognized cause of chorioretinitis, hydrocephalus, microcephaly or macrocephaly, and mental retardation. Acquired LCMV infection, asymptomatic in approximately one third of individuals, is productive of central nervous system manifestations in one half of the remaining cases. Aseptic meningitis or meningoencephalitis are the predominant syndromes, although transverse myelitis, a Guillain-Barré-type syndrome, as well as transient and permanent acquired hydrocephalus have also been reported. Fatalities are rare. We report a patient with meningoencephalitis attributable to LCMV and discuss the spectrum of central nervous system disease, newer diagnostic modalities, and preventive strategies. lymphocytic choriomeningitis virus, aseptic meningitis, meningoencephalitis, zoonosis, hydrocephalus, arenavirus.

Risk assessment of microcystin in dietary Aphanizomenon flos-aquae.

Aphanizomenon flos-aquae, a cyanobacterium that is marketed as a health food supplement, is harvested from natural blooms in Klamath Lake (Oregon) that are occasionally contaminated by Microcystis spp. Regulatory agencies in several countries are developing regulations to control the amount of microcystin in drinking water and other products, including products produced from A. flos-aquae. Regulation of microcystin (MC), a toxin produced by Microcystis spp. that is potentially present in natural culture of A. flos-aquae, should be based on studies in which a test species is exposed to the natural mixture of these cyanobacteria. A 1984 feeding trial to determine the effects of high dietary levels of A. flos-aquae on reproduction and development of mice is reanalyzed in light of recent analyses for microcystin-LR (MCLR) in the diets of those mice. Young adult mice consuming up to 333 microg MCLR/kg body weight (bw)/day exhibited no adverse effects on growth and reproduction, fetal development, and survival and organ weights of neonates. Based on a NOAEL of 333 microg MCLR/kg bw/day, a safety factor of 1000, consumption of 2 g/day of A. flos-aquae by a 60-kg adult, the safe level of MCLR as a contaminant of A. flos-aquae products is calculated to be 10.0 microg MCLR/g.

Purpura fulminans associated with Streptococcus pneumoniae infection in a child.

BACKGROUND: Neisseria meningitidis is the most frequent isolate associated with purpura fulminans in children. Although Streptococcus pneumoniae infection has been associated with purpura fulminans, with the exception of one adult, it has only been reported in immunocompromised hosts. PURPOSE: We report an apparently previously healthy child who presented with purpura fulminans associated with pneumococcal meningitis. METHODS: Case report and review of the medical literature from September 1966 to June 1997, using a MEDLINE search. CONCLUSION: While systemic pneumococcal infection is common in childhood, progression to purpura fulminans does not typically occur in overtly healthy children. Our patient illustrates that invasive pneumococcal infection should be considered and empirically treated in a child who presents with purpura fulminans, even in the absence of preexisting functional or anatomic asplenia.