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Biomedical subjects

M E Peacock

Publications and source records attributed to M E Peacock.

16 recordsLinked to original sources
PubMed2001

Gingival plasma cell granuloma.

Plasma cell granulomas (pseudotumors) are rare benign, tumor-like proliferations composed chiefly of plasma cells that manifest primarily in the lungs, but may occur in various anatomic locations. We report this case of a 54-year-old male who presented with an unusual maxillary anterior gingival overgrowth treated by excisional biopsy. Histological examination revealed a dense inflammatory cell infiltrate containing mainly plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma. Intraoral plasma cell granuloma is exceedingly rare, although case reports documenting such lesions have been reported. This case highlights the need to biopsy unusual lesions to rule out potential neoplasms.

Diagnosis, Differential↗
PubMed2001

Effect of nicotine on fibroblast beta 1 integrin expression and distribution in vitro.

BACKGROUND: Integrins are a family of transmembrane cell surface glycoproteins, and those with the beta 1-subunit function in both cell-to-cell and cell-to-substrate adhesion. The purpose of this study was to determine nicotine's effect on the expression and distribution of the beta 1 integrin subunit on the human gingival fibroblast cell surface. METHODS: Pure nicotine was diluted in medium to the following concentrations: 0 (control), 0.025, 0.05, 0.1, 0.2, and 0.4 microM. Human gingival fibroblasts (HFG) were grown for 24 hours in each concentration and fluorescein-labeled with a mouse monoclonal anti-human beta 1 antibody and secondarily incubated with a urease-labeled anti-mouse IgG antibody. After a final wash, the cells were incubated with urea/bromcresol blue substrate for 15 minutes at 37 degrees C and measured in a microplate reader at 570 nm. RESULTS: The integrin beta 1-subunit was detected on the HGF surface membrane by fluorescence labeling, and cell-enzyme-linked immunosorbent assay testing demonstrated its decreased expression with increasing nicotine concentrations that were statistically different at the concentrations of 0.2 and 0.4 microM versus controls (P < 0.05). CONCLUSIONS: Nicotine concentrations of 0.2 and 0.4 microM significantly decrease beta 1 integrin expression in human gingival fibroblasts that may affect cell-cell and cell-substratum adhesion during wound healing.

Analysis of Variance↗
PubMed2000

Non-Hodgkin's lymphoma and periodontitis. A case report.

BACKGROUND: We describe an unusual case of extra-nodal non-Hodgkin's lymphoma that developed in the maxillae associated with localized severe periodontitis in a 64-year-old Caucasian male. The lymphoma was diagnosed less than 2 years following routine periodontal surgery and 8 weeks after the extraction of hopeless teeth in the associated area. METHODS: Two months following the extractions, the patient experienced pain and swelling in the maxillary right edentulous area mimicking an abscess, and reported for emergency care. An expansile lesion measuring 2.0 x 2.5 cm in diameter was noted on radiographic examination to extend into the right maxillary sinus. A definitive biopsy diagnosis of high-grade, small, non-cleaved, diffuse non-Hodgkin's lymphoma of the right posterior maxillae was established. The patient was subsequently treated by a combination of radiation, chemotherapy, and bone marrow transplantation. RESULTS: The maxillary tissues healed uneventfully, and the patient has been closely observed for approximately 5 years without symptoms or recurrence of the lymphoma. CONCLUSIONS: This case highlights the need for careful debridement of extraction sockets associated with severe periodontitis and argues for the routine submission of extracted teeth with adjacent soft tissue for microscopic analysis, to assist in the early diagnosis of potentially life-threatening malignancies.

Biopsy↗
PubMed2000

Gingival recession treatment using a bilayer collagen membrane.

Traditional periodontal plastic surgery techniques for the management of gingival recession have typically used soft tissue grafts to obtain defect coverage with great clinical success. Clinicians using guided tissue regeneration (GTR) techniques are also enjoying significant success in periodontal plastic surgery procedures. GTR therapy utilizing bioabsorbable membranes offers the advantages of preventing a donor site surgery and a second surgical procedure for barrier removal. A new bioabsorbable bilayer collagen membrane that readily adapts to bone and tooth surfaces by a gel formation of collagen fibers and blood may be stabilized without sutures prior to soft tissue closure. This bioabsorbable membrane has been shown to be effective in guided bone regeneration procedures and in treating periodontal defects. This case demonstrates the treatment of gingival recession with a novel collagen bilayer membrane.

Absorbable Implants↗
PubMed1995

Frequency of self-reported medical conditions in periodontal patients.

Assessing the medical history of patients before any treatment is provided is an essential aspect of the periodontist's responsibility. A patient's compromised medical state could alter the response to periodontal treatment or worse, contribute to a crisis situation that may prove harmful to his or her well-being. This study examines the frequency of medical conditions in periodontal patients utilizing a self-administered health questionnaire succeeded by directly interviewing the patient for validity. Health histories were taken from 590 periodontal patients in an outpatient setting; 52.5% of these patients reported a positive finding in their medical history, with drug allergies and cardiovascular disorders being by far the most frequently found conditions. The frequency of medical conditions increased with increasing age. Thorough evaluation of a patient's health history is a mandatory first step in the treatment process.

Adolescent↗
PubMed1993

The effect of nicotine on reproduction and attachment of human gingival fibroblasts in vitro.

The ability of fibroblasts to reproduce and attach to teeth is of paramount importance in re-establishing the lost connective tissue attachment after periodontal therapy. This study examined the effect of nicotine, a major component of the particulate phase of tobacco smoke, on human gingival fibroblast (HGF) reproduction and attachment to tissue culture surfaces. Pooled HGF cultures made from explants of gingival biopsies were utilized between passages 5 and 10 and plated in 96-well plates at 1.0 x 10(4) cells per well. Cell numbers were determined using 3-(4,5-dimethylthiazol-2-y)-2,5-diphenyl tetrazolium bromide (MTT), which is a reflection of mitochondrial dehydrogenase activity. The concentrations of nicotine used were 0.025, 0.05, 0.1, 0.2, and 0.4 microM, the average serum concentration for a smoker being approximately 0.1 microM. The effect of continuous nicotine exposure on HGF reproduction was determined by incubating cell cultures and media containing nicotine for up to 48 hours. Residual toxicity was determined by preincubating cells with nicotine for 1 or 6 hours. HGF suspensions and increasing concentrations of nicotine were added together to determine the effect on attachment. Results showed an enhanced effect of nicotine on HGF attachment, with increasing numbers of cells attaching with increasing nicotine concentrations, compared to the control. Low concentrations of nicotine had a stimulatory effect on cell replication, while higher concentrations of nicotine appear to have no significant effect on HGF reproduction. The responses of cells to some concentrations of nicotine may persist after its removal.

Analysis of Variance↗
PubMed1991

Angioedema as a complication in periodontal surgery: report of a case.

Angioedema is a diffuse swelling of the subcutaneous or submucosal tissues that occurs in both hereditary and non-hereditary forms. It can be a temporarily disfiguring condition, but not usually a serious one unless the airway is compromised. In the majority of cases, no underlying cause can be identified. In this report, a case of "idiopathic" angioedema that occurred while performing a periodontal surgical procedure is presented. This case is interesting because the patient was on long-term use of an angiotensin-converting enzyme [ACE] inhibitor for hypertension, and recent evidence has shown that ACE inhibitors suppress the breakdown of circulating bradykinins. With high plasma levels of bradykinins, a local anesthetic, periodontal surgical procedures, or even emotional stress may trigger an attack of angioedema. Practitioners should be aware of the pharmacologic side effects of ACE inhibitors and be prepared to handle an emergency if a patient's airway becomes compromised.

Angioedema↗
PubMed1988

Phosphorylation of vitronectin by a protein kinase in human plasma. Identification of a unique phosphorylation site in the heparin-binding domain.

Incubation of human plasma with 27 nM [gamma-32P]ATP in the presence of 20 mM MnCl2 results in the phosphorylation of several proteins detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. About 60% of the incorporated radioactivity is found in a 75-kDa protein containing [32P] phosphoserine. The amino-terminal amino acid sequence of the purified 75-kDa [32P]phosphoprotein is identical to that of vitronectin (also termed serum spreading factor or complement S protein). Rabbit antiserum against vitronectin precipitates greater than 90% of the 75-kDa [32P]phosphoprotein from plasma. Reverse phase chromatography of [32P]vitronectin degraded sequentially with CNBr and chymotrypsin yields one major labeled peptide. The sequence of the peptide, Ser-Arg-Arg-Pro-[32PO4]Ser-Arg-Ala-Thr, corresponds to residues 374-381 which are located in the heparin-binding fragment of vitronectin identified by Suzuki et al. [1984) J. Biol. Chem. 259, 15307-15314). Vitronectin could potentially be phosphorylated in vivo with ATP released from injured cells or secreted by platelets activated during hemostasis.

Binding Sites↗
PubMed1986

Molecular size of dermatan sulfate oligosaccharides required to bind and activate heparin cofactor II.

Heparin cofactor II (HCII) inhibits thrombin rapidly in human plasma in the presence of heparin or dermatan sulfate. To determine the minimum structure of dermatan sulfate required to activate HCII, the glycosaminoglycan was partially degraded by sequential treatment with periodate, [3H]borohydride, and sulfuric acid. Labeled oligosaccharide fragments were separated by gel filtration chromatography. Purified fragments were then applied to a column of HCII bound to concanavalin A-Sepharose, and bound oligosaccharides were eluted with a gradient of sodium chloride. Di-, tetra-, and hexasaccharide fragments did not bind to HCII, while 15% of the octasaccharides and up to 45% of larger fragments bound. Octasaccharides that bound to the HCII column had a greater negative charge than the run-through material based on anion-exchange chromatography, suggesting that they contained a greater number of sulfate groups per molecule. Fragments of dermatan sulfate containing a minimum of 12-14 sugar residues accelerated inhibition of thrombin by HCII. Fragments of this length that bound to the column of immobilized HCII had molar specific activities greater than those of the fragments that did not bind. These studies suggest that HCII is activated by dermatan sulfate fragments greater than or equal to 12 residues in length that contain a specific octasaccharide sequence required for binding to the inhibitor.

Animals↗
PubMed1985

Threshold sensitivity and frequency specificity in auditory brainstem response audiometry.

Frequency-specific electric response audiometry can be performed on difficult to test young children if the child is sedated and proper choices are made of acoustic stimuli and recording parameters, although certain compromises are necessary. A very satisfactory sedative is secobarbital, administered intramuscularly in doses related to the weight of the child. As stimuli we recommend '2-1-2' tone bursts at 500, 1 000, 2 000, and 4 000 Hz: i.e., with a rise and fall of two periods and a plateau of one period of the modulated tone. A very robust and sensitive response that is not significantly modified by the sedation and is effective for all four frequencies is the P6-SN10 of the early brainstem sequence. To record this complex favorably requires a bandpass input filter of the Butterworth type with pass-band (at -3 dB) from 50 to 1 700 Hz and rejection rates of 24 dB/octave. With this combination, polarity of stimulus is unimportant and sweep time, rate of stimulation and number of responses averaged may be selected for convenience and simplicity. A routine that requires about an hour of testing time is described and the necessary correction factors are given for estimating a child's behavioral pure-tone thresholds. We believe that our threshold estimates are generally correct within 10 dB, and are sufficiently frequency-specific for proper selection of a hearing aid.

Acoustic Stimulation↗
PubMedDate not supplied

Gingival augmentation with a dermal allograft.

Gingival augmentation surgery with soft tissue autografts long has been the standard for increasing the width of keratinized oral tissue. Acellular dermal allografts, which have been used for several years by reconstructive surgeons, are a novel technique for achieving increased gingival tissue in place of soft tissue autografts. This report describes a case of gingival augmentation via an acellular dermal allograft. Reduced morbidity from donor site grafts and increased patient acceptance, along with highly successful clinical results, are the primary advantages of this acellular dermal allograft.

Adult↗
PubMedDate not supplied

Treatment of gingival recession with collagen membranes.

Periodontal plastic surgical techniques to obtain root coverage traditionally have utilized autogenous soft tissue grafts. Guided tissue regeneration (GTR) increasingly is being used as an alternative to soft tissue grafting in attempting root coverage. Resorbable membranes in GTR therapy prevent the need for a second surgery to harvest donor tissue. GTR membranes composed of collagen are effective barriers that add to the thickness of the overlying gingiva and possess platelet-aggregating properties that may help in early wound healing. The cases presented here demonstrate the treatment of gingival recession with a resorbable collagen membrane.

Absorbable Implants↗
PubMedDate not supplied

Periodontal plastic surgical technique for gingival fenestration closure.

Gingival fenestration is an opening through oral keratinized tissue, usually unattached, that is observed in thin gingiva with usually thick subgingival calculus deposits. This lesion is seen infrequently but may be more common than has been reported; lack of symptoms may inhibit patient awareness. Because surgical correction usually is not required, there are very few reports in the literature concerning this lesion. The following report describes a case of gingival fenestration and surgical treatment with a connective tissue/periosteal graft.

Adult↗
PubMedDate not supplied

Frenotomy and keratinized tissue augmentation.

Aberrant frenula can be an important etiological factor in progressive gingival recession. When separating or removing frenula, augmentation with keratinized tissue is the treatment of choice in most circumstances. A case is described as a mandibular labial frenotomy in combination with a free gingival graft.

Adult↗