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Biomedical subjects

T F Meiller

Publications and source records attributed to T F Meiller.

At least 37 records · Page 2Linked to original sources
PubMed1999

Coaggregation of Candida dubliniensis with Fusobacterium nucleatum.

The binding of microorganisms to each other and oral surfaces contributes to the progression of microbial infections in the oral cavity. Candida dubliniensis, a newly characterized species, has been identified in human immunodeficiency virus-seropositive patients and other immunocompromised individuals. C. dubliniensis phenotypically resembles Candida albicans in many respects yet can be identified and differentiated as a unique Candida species by phenotypic and genetic profiles. The purpose of this study was to determine oral coaggregation (CoAg) partners of C. dubliniensis and to compare these findings with CoAg of C. albicans under the same environmental conditions. Fifteen isolates of C. dubliniensis and 40 isolates of C. albicans were tested for their ability to coaggregate with strains of Fusobacterium nucleatum, Peptostreptococcus micros, Peptostreptococcus magnus, Peptostreptococcus anaerobius, Porphyromonas gingivalis, and Prevotella intermedia. When C. dubliniensis and C. albicans strains were grown at 37 degrees C on Sabouraud dextrose agar, only C. dubliniensis strains coaggregated with F. nucleatum ATCC 49256 and no C. albicans strains showed CoAg. However, when the C. dubliniensis and C. albicans strains were grown at 25 or 45 degrees C, both C. dubliniensis and C. albicans strains demonstrated CoAg with F. nucleatum. Heating the C. albicans strains (grown at 37 degrees C) at 85 degrees C for 30 min or treating them with dithiothreitol allowed the C. albicans strains grown at 37 degrees C to coaggregate with F. nucleatum. CoAg at all growth temperatures was inhibited by mannose and alpha-methyl mannoside but not by EDTA or arginine. The CoAg reaction between F. nucleatum and the Candida species involved a heat-labile component on F. nucleatum and a mannan-containing heat-stable receptor on the Candida species. The CoAg reactions between F. nucleatum and the Candida species may be important in the colonization of the yeast in the oral cavity, and the CoAg of C. dubliniensis by F. nucleatum when grown at 37 degrees C provides a rapid, specific, and inexpensive means to differentiate C. dubliniensis from C. albicans isolates in the clinical laboratory.

Amino Acids↗
PubMed1999

Dental unit waterlines: biofilms, disinfection and recurrence.

BACKGROUND: Transmission of microbial pathogens to patients from biofilm within dental unit waterlines, or DUWLs, is a concern. To reduce the risk of toxicity to dental patients when water coolants are used, numerous chemical agents have been tested. In a series of trials, the authors investigated the recurrence of microbial growth after treating DUWLs with sodium hypochlorite (bleach), or B; glutaraldehyde, or G; or isopropanol 15.3 percent, or I. METHODS: The authors excised tubing sections from dental units in a general clinic. The tubing sections were evaluated at baseline and after overnight treatment. Effluent water samples and biofilm samples from tubing sections also were evaluated, by culture, at baseline and after treatment with the chemical agents. Biofilm within the tubing was examined by scanning electron microscopy, or SEM, and the authors identified bacterial isolates using standard techniques. The authors performed minimum inhibitory concentration tests on identified isolates pre- and posttreatment and compared the results to determine possible differences in resistance. RESULTS: In baseline evaluations, the authors determined that the effluent and biofilm matrix harbored an average of 1 x 10(5) colony-forming units, or CFU, per square centimeter and 1 x 10(4) CFU/cm2 recoverable microorganisms, respectively. A single overnight treatment of the DUWLs with B, G or I rendered effluent and biofilm samples that were free of recoverable bacteria. The number of viable bacteria in the effluent and the biofilm of B- or I-treated DUWLs returned to pretreatment levels by day six and day 15, respectively. DUWLs treated with G showed evidence of bacterial recurrence in the effluent and the biofilm to pretreatment levels by day three. The authors compared recurrence of biofilm and effluent posttreatment with untreated control tubing. The lower recurrence of viable bacteria in both biofilm and effluent samples for tubing treated with B and I was significant (P < or = .05). No evidence of resistance to the agents was noted during the study. Multiple treatments held the bacterial population to below recoverable levels but failed to remove the biofilm matrix, as evidenced by SEM. CONCLUSIONS: B, G and I eliminated recoverable bacteria after treatment and inhibited their recurrence in DUWL. Recolonization rates varied by agent. CLINICAL IMPLICATIONS: The residual effect of these agents raises concerns about the slow release of potentially toxic substances from the residual biofilm matrix. These agents reduce microorganisms in effluent water but do little to destroy the biofilm matrix in the DUWL, even with periodic treatments. Bacterial populations in the dental unit water rapidly recolonize the DUWL. Chemical agents or agents that potentially could be trapped in the matrix can represent an additional risk to the patient.

2-Propanol↗
PubMed1999

The effects of HIV viral load on the phagocytic activity of monocytes activated with lipopolysaccharide from oral microorganisms.

A study was undertaken to determine whether viral load status in HIV+ patients has any potential effect on monocyte phagocytic function both before and after challenge of the monocytes with lipopolysaccharide (LPS) isolated from oral microorganisms. LPS of two putative periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum) was prepared. Whole blood samples in EDTA were collected from 30 HIV+ patients presenting for dental care at the University of Maryland. Control samples were prepared from appropriate uninfected individuals. Viral load was determined using quantitative RT-PCR (Amplicor, Roche Diagnostics). Phagocytic function was determined using FITC labeled Saccharomyces species in resting isolated monocytes and in cells after 24 h stimulation with 1 microgram/ml of LPS of P. gingivalis or F. nucleatum. Immunohistochemical staining was performed for complement receptor CR-1 (CD-35) on phagocyte cells. In HIV+ patients with high viral load (> 10,000 copies/ml), 13.5% of isolated resting monocytes demonstrated phagocytic activity, while 23% of the resting control monocytes from non-infected individuals showed phagocytic function. When the monocytes were stimulated with 1 microgram/ml of LPS of F. nucleatum, phagocytic activity was observed in 18.5% of monocytes in patients with high viral load, 33.5% with moderate viral load (400-10,00 copies/ml) and 51% with low viral load (<400 copies/ml), while 62% of the control monocytes demonstrated phagocytic activity. Stimulation of monocytes with LPS of P. gingivalis showed similar results. Complement receptor CD-35 showed a 50% decrease in expression in HIV+ patients with high viral load. A progressive decrease in monocyte/macrophage phagocytic function and CD-35 expression with and without oral LPS activation occurs after HIV infection and this trend appears to be accentuated in patients with high viral load. This relationship may contribute to increased susceptibility to oral opportunistic infections in advanced HIV+ patients.

Adult↗
PubMed1998

Interleukin-6 production by human monocytes treated with granulocyte-macrophage colony-stimulating factor in the presence of lipopolysaccharide of oral microorganisms.

This study focused on the effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) and lipopolysaccharide of the putative periodontal pathogens Porphyromonas gingivalis or Fusobacterium nucleatum on IL-6 production by THP-1 cells (a human monocytic cell line). Resting THP-1 cells were alternatively treated with GM-CSF (50 IU/ml) and lipopolysaccharide of P. gingivalis or F. nucleatum, in varying concentrations for varying time periods. IL-6 production in supernatant fluids of treated cells was evaluated by an enzyme-linked immunosorbent assay (ELISA) and a reverse transcription polymerase chain reaction (RT-PCR) was used to evaluate gene expression. Untreated THP-1 cells did not produce IL-6 as determined by ELISA. RT-PCR also failed to detect IL-6 mRNA in untreated THP-1 cells, indicating that IL-6 was not constitutively produced. After stimulation of THP-1 cells with lipopolysaccharide of F. nucleatum or P. gingivalis, IL-6 was produced, peaking at 4 h (200-300 pg/ml) and thereafter sharply declining by 8 h. When GM-CSF was added together with lipopolysaccharide of P. gingivalis or F. nucleatum, there was a synergistic quantitative increase in production of IL-6 as measured by ELISA as compared with lipopolysaccharide alone. IL-6 mRNA was detected by RT-PCR, 15 min after stimulation with lipopolysaccharide of either P. gingivalis or F. nucleatum. GM-CSF supplementation with lipopolysaccharide of P. gingivalis shortened the transcription of IL-6 mRNA to 5 min, a shift which was not observed with lipopolysaccharide of F. nucleatum, possibly indicating a different mechanism of initiation of transcription. Production of IL-6 by GM-CSF-treated THP-1 cells in the presence of lipopolysaccharide of oral microorganisms may provide a model for studying the role of macrophages in acute and chronic periodontal diseases, including the clinical periodontal exacerbation as observed in chemotherapy patients receiving GM-CSF for bone marrow recovery.

Analysis of Variance↗
PubMed1998

Granulocyte-macrophage colony-stimulating factor amplification of interleukin-1beta and tumor necrosis factor alpha production in THP-1 human monocytic cells stimulated with lipopolysaccharide of oral microorganisms.

Cytokines, including granulocyte-macrophage colony-stimulating factor (GM-CSF), are used to assist in bone marrow recovery during cancer chemotherapy. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) play important roles in inflammatory processes, including exacerbation of periodontal diseases, one of the most common complications in patients who undergo this therapy. A human monocyte cell line (THP-1) was utilized to investigate IL-1beta and TNF-alpha production following GM-CSF supplementation with lipopolysaccharide (LPS) from two oral microorganisms, Porphyromonas gingivalis and Fusobacterium nucleatum. LPS of P. gingivalis or F. nucleatum was prepared by a phenol-water extraction method and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and determination of total protein and endotoxin contents. Resting THP-1 cells were treated with LPS of P. gingivalis or F. nucleatum and/or GM-CSF (50 IU/ml) by using different concentrations for various time periods. Production of IL-1beta and TNF-alpha in THP-1 cells was measured by solid-phase enzyme-linked immunosorbent assay. Reverse transcription (RT)-PCR was used to evaluate the gene expression of resting and treated THP-1 cells. IL-1beta was not detected in untreated THP-1 cells. IL-1beta production was, however, stimulated sharply at 4 h. GM-CSF amplified IL-1beta production in THP-1 cells treated with LPS from both oral anaerobes. No IL-1beta-specific mRNA transcript was detected in untreated THP-1 cells. However, IL-1beta mRNA was detected by RT-PCR 2 h after stimulation of THP-1 cells with LPS from both organisms. GM-CSF did not shorten the IL-1beta transcriptional activation time. GM-CSF plus F. nucleatum or P. gingivalis LPS activated THP-1 cells to produce a 1.6-fold increase in TNF-alpha production at 4 h over LPS stimulation alone. These investigations with the in vitro THP-1 model indicate that there may be an increase in the cellular immune response to oral endotoxin following GM-CSF therapy, as evidenced by production of the tissue-reactive cytokines IL-1beta and TNF-alpha.

Bacteroidaceae↗
PubMed1998

Functional changes in THP-1 human monocytic cells after stimulation with lipopolysaccharide of oral microorganisms and granulocyte macrophage colony stimulating factor.

A human THP-1 monocyte cell line culture system has been utilized to observe the effect of granulocyte macrophage colony stimulating factor (GM-CSF) supplementation with lipopolysaccharide (LPS) of oral microorganisms to stimulate monocyte/macrophage functional activity. LPS of oral microorganisms, Fusobacterium nucleatum and Porphyromonas gingivalis was produced by phenol-water extraction and characterized. The phagocytosis assay was performed using F1TC labeled Saccharomyces yeast particles. Phagocytic functional activity was observed in 10-11% of resting THP-1 cells. Treatment of THP-1 cells with LPS of F. nucleatum or P. gingivalis increased the phagocytic activity of THP-1 cells 2-3 fold. GM-CSF significantly increased phagocytosis either alone or when supplemented with LPS of F. nucleatum or P. gingivalis. A chemotaxis assay was performed using a 48 well chemotaxis chamber. Chemotactic functional activity of THP-1 cells was increased 2-fold after 4 days of treatment with GM-CSF. Stimulation of THP-1 cells with LPS of F. nucleatum or P. gingivalis significantly reduced the chemotactic activity indicating the maturation towards a fixed macrophage. There were functional variations (chemotaxis and phagocytosis) in THP-1 cells in response to LPS of oral microorganisms following stimulation with GM-CSF.

Cell Line↗
PubMed1996

Effect of an antiseptic mouthrinse on salivary microbiota.

PURPOSE: To evaluate the effect of rinsing with original formulation Listerine Antiseptic (LA) on the level of viable salivary bacteria for periods up to 1 hour. MATERIALS AND METHODS: In this double-blind, controlled, cross-over study, unstimulated saliva was collected from 25 subjects, serially diluted, and cultured on selective and non-selective media under aerobic and anaerobic conditions. Streptococci, Veillonella sp., and total aerobic and anaerobic flora were enumerated just prior to and 2, 15, 30, and 60 minutes after rinsing for 30 seconds with either 20 ml of LA or a 5% hydroalcohol control rinse. RESULTS: After the control rinse, total flora cultivated on MM10 agar exhibited a non-significant (P > 0.05) 10%-20% decrease relative to baseline. In contrast, rinsing with LA resulted in a significant (P < 0.05) 60%-65% decrease from baseline in all four microbial groups at 2 minutes; except in the case of Veillonella, the significant decreases were sustained up to 60 minutes. Total Listerine group aerobic, anaerobic and streptococcal counts were significantly lower than placebo (P < 0.05). The significant reduction in salivary bacterial levels seen in the Listerine group for up to 60 minutes suggests that this antiseptic mouthrinse may have use clinically as a pre-procedural rinse to decrease the level of viable microorganisms in aerosols generated during dental procedures.

Adult↗
PubMed1995

Early appearance of antibodies to simian immunodeficiency virus in saliva and serum of infected macaques.

Simian immunodeficiency virus (SIV) infection in macaques is an important animal model for human immunodeficiency virus infection in humans. This study evaluated the temporal development of antibodies to SIV in the parotid saliva of macaques inoculated with the virus and compared these findings with the development of antibodies to SIV in the animals' sera. Three animals (ages, 14, 18, and 18 years) were inoculated with the macrophagetropic strain SIVmac239. Prior to inoculation and at consecutive weekly intervals during a four-week period following the initial virus inoculations, parotid saliva and serum were collected from each animal. A fourth animal (age, 9 years) served as a negative control, and the fifth and sixth animals (ages, 2 and 22 years) served as positive controls (6 and 18 months postinoculation, respectively) with SIVmac239. Saliva and serum samples were reacted against SIV antigen in Western blots (immunoblots) prepared in the standard fashion to determine the presence of antibodies. The reactions of these antigen-antibody complexes with biotinylated anti-human immunoglobulin A (IgA), IgM, and IgG and biotinylated anti-human secretory component (SC) determined the class of antibody present or the presence of SC in the original parotid saliva or serum samples. In infected animals, the IgM to SIV was detectable in serum and saliva at 13 days, and antiviral IgA and IgG in serum and saliva were detectable at 20 to 27 days postinoculation. The antibody to SC reacted to saliva from only two animals at 20 and 27 days, and long-term positive controls were positive for SC in saliva, indicating that either secretory IgA or secretory IgM was present in these samples. Antibodies to SIVmac239 antigens have therefore been detected in saliva as early as 13 days postinfection. Saliva may be as useful as serum as a diagnostic specimen and/or disease-monitoring method in this important animal model.

Animals↗
PubMed1991

Effect of an antimicrobial mouthrinse on recurrent aphthous ulcerations.

Recurrent aphthous ulceration (RAU) remains a clinical problem for many patients. Efforts in prevention and/or treatment with prescription and nonprescription formulations have to date resulted in minimal success at best. A 6-month double-blind clinical study of 96 adults compared a commercially available antimicrobial mouthrinse (Listerine Antiseptic [LA], Warner-Lambert Co., Morris Plains, N.J.) and a hydroalcoholic control to evaluate the effects of vigorous twice-daily rinsing on the incidence, duration, and severity of RAU in persons prone to this disorder. LA rinse and the hydroalcoholic rinse resulted in a statistically significant reduction in the incidence of RAU occurrences from baseline. The duration of lesions and the severity of pain in subjects with ulcers during the treatment period were also significantly reduced in the LA rinse group of patients when compared with baseline. The hydroalcoholic rinse did not show a significant effect versus baseline for either severity or duration of the lesions. Rinsing therefore can be of clinical value in reducing the occurrence of RAU in susceptible patients, and LA rinse can be of significant additional value in decreasing the duration and severity of RAU.

Adolescent↗
PubMed1990

Comparative effects of 2 chemotherapeutic mouthrinses on the development of supragingival dental plaque and gingivitis.

A 6-month double-blind, controlled clinical study was completed with 124 healthy adult subjects to determine the efficacy of 2 mouthrinses, Listerine (LA) and Peridex (PX), used as supplements to regular oral hygiene measures in reducing supragingival dental plaque and gingivitis. Following screening examinations for entry levels of existing gingivitis and plaque, baseline gingival and plaque area indices, extrinsic tooth stain, supragingival calculus, bleeding and soft tissue condition were recorded. All subjects then received a complete dental prophylaxis to remove plaque, calculus and extrinsic stain. Subjects were randomly assigned to 1 of 3 groups and performed supervised rinses twice daily for 30 s in addition to their normal oral hygiene, for 6 months. All indices were again evaluated at 3 and 6 months. After 6 months, LA and PX significantly (p less than 0.001) inhibited development of plaque by 36.1% and 50.3%, respectively, and the development of gingivitis by 35.9% and 30.5%, respectively, compared to a hydroalcohol control. PX was more effective in inhibiting plaque and both mouthrinses appeared to be equally effective in inhibiting gingivitis. LA patients did not develop significant levels of stain or supragingival calculus at 6 months, compared to baseline or control. PX patients developed significant levels of extrinsic stain and supragingival calculus compared to baseline and control. Though PX was more effective than LA in the control of plaque, this study indicates that both LA and PX were effective agents in a regimen for the control of plaque and gingivitis.

Adult↗
PubMed1989

Effects of 6 months use of an antiseptic mouthrinse on supragingival dental plaque microflora.

This study was undertaken to determine whether long-term use (6-months) of an antiseptic mouthrinse (Listerine Antiseptic, Warner Lambert Co., Morris Plains, NJ, USA) led to an undesirable succession of oral pathogens or the emergence of resistant microbial forms. Supragingival plaque was collected from 83 subjects before treatment and after either 3 or 6 months use of either the active antiseptic or a 5% hydroalcohol control. Subjects rinsed with their assigned mouthrinse twice daily under supervision. The plaque samples were analyzed for microbial content by darkfield microscopy, culture on a series of nonselective and selective bacterial media, and by recognition of microbial forms by recognition of distinct colony on a nonselective medium. Statistical analysis of the results revealed no significant microbial shifts including no significant increases in presumptive oral pathogens, spirochetes, black-pigmented Bacteroides, Streptococcus mutans, or Candida albicans. Additionally, no detectable rise in either staphylococci or enteric bacteria, potential opportunistic pathogens, was observed.

Adolescent↗
PubMed1989

Chemotherapeutic inhibition of supragingival dental plaque and gingivitis development.

A 6-month double-blind, controlled clinical study was conducted on 107 healthy adult subjects to determine the efficacy of a mouthrinse used as a supplement to regular oral hygiene measures on supragingival dental plaque and gingivitis. 115 healthy adult patients were recruited for the study. Following screening examinations for minimal entry levels of existing gingivitis and plaque in patients with a minimum of 20 sound natural teeth, extrinsic tooth stain, gingivitis and plaque index scores were recorded. Soft tissues were evaluated. All subjects then received a complete dental prophylaxis, removing plaque, calculus and extrinsic stain. Utilizing their normal oral hygiene, subjects began a regimen of rinsing with 20 ml of the randomly assigned rinse, twice daily for 30 s for 6 months. 7 days after prophylaxis, gingivitis was again scored (baseline 2). Soft tissue, gingivitis, plaque area and extrinsic stain were evaluated again at 3 and 6 months. Results demonstrated that after 6 months, listerine produced a 34% inhibition of both plaque and of gingivitis compared to a hydroalcohol control (p less than 0.001).

Adolescent↗
PubMed1987

Evaluation of a monoclonal antibody typing system for herpes simplex virus.

This study compared conventional viral isolation (VI) in cell cultures with a commercial product--Virgo antigen detection system--for the identification and typing of herpes simplex virus (HSV). The system is designed to identify and type HSV from direct lesion smears (DS) and from cell culture smears (CS) infected with a swab from the patient's lesion by means of an indirect fluorescence assay (IFA) using HSV type-common and HSV-2 type-specific monoclonal antibodies. A total of 71 coded specimens manifesting clinical characteristics consistent with HSV were included in this evaluation from which DS, CS, and VI were performed. Specimens were taken from a variety of intraoral and extraoral sites, from both recurrent and primary lesions, and at various stages of lesion progression. The results showed that HSV was not detected in 22 of the 71 specimens by either DS, CS, or VI. Forty-nine specimens were positive by both CS and VI; 47 of these were typed as HSV-1 and 2 were typed as HSV-2. Thirty-eight of the 49 positive CS and VI specimens also were positive by DS. The remaining 11 DS slides did not have sufficient cells for analysis. It was concluded that the success of a valid DS test depended on the stage of the lesion and the sampling technique. The sensitivity and specificity of CS and DS were 100% and 82%, respectively, for detection of virus when compared with VI. When done properly with an adequate number of cells from the lesion, the DS proved to be an accurate and rapid (2 hours) procedure.

Adolescent↗
PubMed1983

Blood pressure fluctuations in hypertensive patients during oral surgery.

The lability of blood pressure during oral surgical procedures and the effects of antihypertensive drugs on this lability have not been investigated sufficiently to evaluate potential medical risks. The purpose of this study was to accurately evaluate blood pressure fluctuations during oral surgical procedures in three groups of patients: normotensive patients; stratum I hypertensive patients not taking medication; and stratum I hypertensive patients taking antihypertensive medication. Blood pressure measurements were recorded by an American Heart Association certified technician at baseline, immediately prior to surgery, during administration of the local anesthetic, during the surgical procedure, and 15 minutes after surgery. Analysis of variance indicated that the blood pressure fluctuations (systolic and diastolic) among these five intervals were not statistically significant for any of the groups. The clinical significance of the above findings is that stratum I hypertensive patients experience minimal fluctuations in blood pressure that are no greater than those in normotensive patients and, therefore, may present no greater clinical risk during the dental stress associated with certain oral surgical procedures.

Antihypertensive Agents↗