Biomedical subjects

Linda C Duffy

Publications and source records attributed to Linda C Duffy.

4 recordsLinked to original sources

PubMed2004

In vivo effects of bifidobacteria and lactoferrin on gut endotoxin concentration and mucosal immunity in Balb/c mice.

The aim of the present study was to examine the effects of oral supplementation of newborn Balb/c mice with bifidobacteria (B. infantis, B. bifidum) and iron-free apo-lactoferrin (bovine, human) on gut endotoxin concentration and mucosal immunity. Endotoxin concentration was measured in ileocecal filtrates at 7, 14, 21, and 28 days postdelivery by a quantitative limulus amebocyte lysate test. While endotoxin levels in bifidobacteria-fed mice showed a steady rise over time, they were consistently lower than that observed in control animals. Results of lactoferrin supplementation varied depending on the specific time point, but overall by day 28, all treatment groups showed lower intestinal endotoxin concentrations compared to saline fed animals. Neither bifidobacteria nor lactoferrin stimulated an increase in B or T cells, or in cytokine production (IL-6, TNF-alpha, INF-gamma), in Peyer's patches as measured by flow cytometry. Bifidobacteria and lactoferrin were well tolerated as dietary supplements and showed promising potential to reduce gut endotoxin levels.

Administration, Oral↗

PubMed2003

In vitro growth responses of bifidobacteria and enteropathogens to bovine and human lactoferrin.

A series of in vitro experiments was performed to test the ability of bovine and human lactoferrin to influence the growth of the gram-positive probiotic bacteria, Bifidobacterium bifidum, Bifidobacterium infantis, and Lactobacillus acidophilus, as well as the gram-negative enteric bacteria, E. coli O157:H7 and Salmonella typhimurium. None of the lactoferrin preparations stimulated the growth of the tested strains. However, iron-free apo-lactoferrin (bovine and human) and 66% iron-saturated bovine lactoferrin dramatically slowed the growth of E. coli O157:H7 in single culture experiments, while 98% iron-saturated preparations had no effect. In coculture experiments of B. infantis and E. coli, the iron-limited preparations of lactoferrin also slowed the growth of the latter without inhibiting the bifidobacteria. These results suggest that lactoferrin in iron-limited forms may have the potential to be combined with probiotic bacteria in biotherapeutic products, which could help balance human gut microflora and limit the overgrowth of certain enteric microorganisms.

Animals↗

PubMed2003

Improvements in immunization compliance using a computerized tracking system for inner city clinics.

Vaccination compliance rates were calculated for 1995 to 2001 for enrolled patients, based on the Centers for Disease Control and Prevention guidelines and age-appropriate vaccine schedules. The results reported here indicate computerized tracking with the Doctor's Pediatric Immunization Program (Dr. PIP) maintained vaccine compliance rates (> 90%) in healthy and immunocompromised children at 2 months and 12 months of age. Instituting the computerized system has yielded nearly optimal results in both indigenous inner-city clinics. Despite the efficient progress made by automated tracking, the results for specific vaccine strategies (Varicella) and target groups (human immunodeficiency virus, high-risk indigent populations) may require on-going and intensive educational efforts to achieve optimization levels.

Adolescent↗

PubMed2002

Immune responses in rhesus rotavirus-challenged BALB/c mice treated with bifidobacteria and prebiotic supplements.

Bifidobacterium species (B. bifidum and B. infantis), with or without prebiotic compounds (arabino-galactan, short-chain fructo-oligosaccharide, iso-malto-dextrins), were orally fed to Balb/c pups (n = 192) to evaluate their potential synergistic effects on modulating the course of rhesus rotavirus (RRV) infection, as well as their ability to mediate the associated mucosal and humoral immune responses. Rotavirus-specific IgA and IgG in serum, rotavirus antigen, and specific IgA in feces were measured by ELISA. Mucosal total IgA and IgG levels were determined in Peyer's patches by flow cytometry. Significantly delayed onset (p = 0.001) and early resolution (p < 0.001) of diarrhea were observed in bifidobacteria-treated, RRV-infected mice compared with RRV-infected control mice. Supplementation with prebiotic compounds did not shorten the clinical diarrhea course more than that observed with bifidobacteria treatment alone. Rotavirus-specific IgA in feces was 16-fold elevated on d 5 postinfection in bifidobacteria-treated, RRV-infected mice compared with the RRV-infected alone group. In addition, the level of rotavirus-specific IgA in serum was four-fold higher in bifidobacteria-treated, RRV-infected litters versus mice challenged with RRV alone on 28 and 42 d postinfection. No enhancement of the immune response was found in RRV-infected mice that were treated with both bifidobacteria and prebiotic compounds over those treated with bifidobacteria only. The findings suggest that bifidobacteria may act as an adjuvant by modulating early mucosal and strong humoral rotavirus-specific immune responses, and mitigate severity of rotavirus-induced diarrhea.

Animals↗