PubMed Health⌕ Search

Biomedical subjects

T H Morton

Publications and source records attributed to T H Morton.

At least 19 recordsLinked to original sources
PubMed2000

Expression of the antimicrobial peptide, human beta-defensin 1, in duct cells of minor salivary glands and detection in saliva.

The oral cavity is exposed to a variety of environmental insults. Salivary secretions play a critical role in maintaining oral health via innate host defense mechanisms and secretion of secretory IgA. Human beta-defensins (hBD) are antimicrobial peptides that are a component of the innate immune response; they are expressed in epithelia and are proposed to have a role in mucosal defense. hBD-1 mRNA is constitutively expressed in numerous mucosal tissues, including human gingiva and submandibular and parotid glands. Our objective was to detect the expression and localization of hBD-1 peptide in human salivary glands and in saliva. Minor salivary gland tissue was obtained from biopsies of patients with mucoceles (n = 20). hBD-1 peptide was detected by immunohistochemistry; expression was localized to the ductal cells and not the acinar cells of these glands. The peptide was located apically, toward the lumen in the duct cells. Further evaluation showed stronger hBD-1 expression in ducts with periductal inflammation, as indicated by the immunostaining of serial sections with anti-CD45 specific for B- and T-lymphocytes. Statistical analysis showed a strong correlation of hBD-1 staining and inflammation. Results of immunolocalization suggest that hBD-1 functions to protect salivary glands from retrograde infection, that expression of the peptide is enhanced in inflamed sites, and that post-transcriptional regulatory mechanisms may be involved in hBD-1 peptide expression. Western immunoblot analysis also detected hBD-1 peptide in unstimulated, whole, acidified saliva from normal volunteers. However, hBD-1 peptide associated with salivary mucin resulted in loss of the detection in a dot-immunoblot assay. Association of hBD-1 with salivary mucin may facilitate peptide distribution and adherence to oral surfaces and aid its function within the oral cavity.

Adult↗
PubMed1993

Argon laser oral safety parameters for teeth.

Argon lasers have been reported to prevent or reduce demineralization of enamel in extracted teeth and to polymerize dental composites (using 25-100 J/cm2). Prior to clinical trials on caries prevention and curing composites, safety parameters for intraoral use of the argon laser need to be established. This study was conducted to determine the enamel damage, pulp temperature changes, and associated pulpal tissue damage following irradiation at various argon laser energy levels using 1.6-6.0 watts, approximately 1 and 2 mm diameter beam for 0.2-5.0 seconds. To evaluate pulpal damage, selected dogs' teeth were irradiated in vivo, extracted 7 days postlasing, fixed, decalcified, sectioned, stained, and read for pulpal damage. Pulp temperature and enamel damage tests utilized extracted dog and human teeth. Temperature probes were inserted in the pulp chambers and temperature changes recorded as enamel surface was lased. Enamel surface damage was evaluated by visual and microscope examination. Results showed that histologic pulpal damage occurred at > 600 J/cm2. Temperature changes were < 6 degrees F in human teeth with approximately 900 J/cm2. No enamel damage was observed at these energy densities. At energy densities needed for proposed uses, no apparent damage would be expected to pulp or enamel.

Animals↗
PubMed1991

Ulcerative lesions of the palate associated with removable partial denture castings.

Regions of inflammation with or without ulceration beneath removable partial dentures have been of concern to prosthodontists for many years. The etiology of these lesions has not been established, but potential factors are microbial infection, obstructive sialadenitis, and allergic-type reactions to the metal framework. A new etiological factor that may be involved is described. Focal pitting corrosion and by-products of corrosion in nickel-chromium alloys are discussed as toxic agents responsible for palatal lesions. Six patient reports that include results of tissue biopsy and EDAX analysis of casting are presented.

Adult↗
PubMed1990

Carbon dioxide laser oral safety parameters for teeth.

The carbon dioxide laser is used in the oral cavity for a variety of procedures. Although the procedures may not involve the teeth directly, precaution should be exercised to preserve their integrity. The results of this study indicate that the most limiting parameter for oral use of the CO2 laser is damage to the enamel surface, which could be inflicted with as little as 5 W for 0.2 second and a 1 mm beam. Care should be exercised to prevent inadvertent damage to the surface enamel of teeth even at very low energy levels.

Animals↗
PubMed1990

Hyperostosis and fixed partial denture pontics: report of 16 patients and review of literature.

A total of 19 hyperostoses underlying mandibular posterior fixed partial dentures were observed in 16 patients. In three patients the lesions were bilateral. Histologic examination of hyperostoses from eight patients showed that they were composed essentially of hyperplastic lamellar bone. Radiographic and clinical evidence suggested that subpontic hyperostoses are chronic, slow growing lesions with an exclusive predilection for the mandibular molar-premolar site. They appear to have variable growth rates and attain widely variable maximum size. The etiology of subpontic hyperostoses is unknown, but it is possible that inflammation, trauma, mandibular and occlusal function, and genetic factors, either individually or in combination, play a role in the initiation and development of these lesions. Subpontic hyperostoses have potential periodontal and restorative implications that may require their surgical removal.

Adult↗
PubMed1990

Antibody HMB-45 identifies the cells of blue nevi. An immunohistochemical study on paraffin sections.

Sixteen cases of blue nevi were investigated using the anti-melanoma specific antibody HMB-45. This antibody has been found to react with junctional but not with intradermal nevus cells, and with fetal and neonatal, but not with adult, melanocytes. Our study shows that HMB-45 also reacts with cells of the blue nevus, a unique type of intradermal nevus. The origin of blue nevus cells is controversial, and the results of this study support the hypothesis that blue nevus cells are not of purely melanocytic or Schwannian origin, but are derived from a precursor cell that has some common features of both melanocyte and Schwann cell.

Antibodies, Monoclonal↗
PubMed1989

Pulpal response to irradiation of enamel with continuous wave CO2 laser.

Selected dog's teeth, in vivo, were exposed to carbon dioxide (CO2) laser power densities ranging from 13 to 102 J per cm2. The teeth were extracted 48 h postlasing, fixed with 10% neutral buffered formalin, decalcified with Kristensen's solution, processed, sectioned, stained, and evaluated for pulpal damage. No pulpal damage was observed when compared with nonlased control teeth. It appears that carbon dioxide laser power densities of approximately 13 to 102 J per cm2 could be used to irradiate enamel of teeth without damage to the pulp.

Animals↗
PubMed1989

Dental identification in serial homicides: the Green River Murders.

At least 40 young women have died at the hands of a serial killer in what has been called the Green River Murders. Because most of the victims' remains were severely decomposed with partial or complete skeletonization and little or no personal effects were recovered, forensic odontologic methods played a key role in their identifications. Although numerous methods were used to accumulate leads to the identities of the badly decomposed skeletonized remains, leads generated through traditional investigative methods established the identities in most cases. Of 40 victims, 36 have now been identified, mainly by means of dental evidence. This article details the challenges presented by serial homicides and the key role of forensic odontologic methods in the Green River Murders investigation.

Adolescent↗
PubMed1987

Plexiform unicystic ameloblastoma of the maxilla.

Plexiform unicystic ameloblastomas have a marked predilection for occurring in the posterior part of the mandible. This article presents the first report of such a lesion in the maxilla.

Ameloblastoma↗
PubMed1987

Identification of Merkel cells in oral epithelium using antikeratin and antineuroendocrine monoclonal antibodies.

Merkel cells are a rare cell type located at or near the basal lamina of oral epithelia and epidermis. They are associated with nerves, and may function as touch receptors. Merkel cells are difficult to identify by routine light microscopy, but have been identified by electron microscopy and specific antibodies. We demonstrate here that Merkel cells can be identified by immunohistochemistry, using a monoclonal antibody (LK2H11, Lloyd and Wilson, 1983) to neuroendocrine granules, and a monoclonal antibody (35 beta H11, Gown and Vogel, 1982) to a 54-kD keratin generally located in simple epithelia but not in stratified epithelia. Human oral tissue was fixed in Carnoy's fixative, and adjacent serial sections were stained with the two antibodies. Individual positively-stained cells were generally located at the bases of rete ridges. Cells in the same position in adjacent sections stained with both antibodies. Essentially all cells (94%) staining for neuroendocrine granules also gave a positive reaction for the 54-kD keratin, evidence that a single Merkel cell contains neuroendocrine granules and the 54-kD keratin. Staining of epithelial sheets of human oral tissues revealed a linear distribution of Merkel cells along the bases of rete ridges. We concluded that antibodies to simple epithelial keratins and neuroendocrine granules may be excellent immunohistochemical markers for Merkel cells, thus facilitating future studies to examine changes in Merkel cells and their distribution in pathologic conditions. The observation that Merkel cells can be stained with an antikeratin antibody strongly supports the epithelial origin of these cells.

Antibodies, Monoclonal↗
PubMed1984

Radioprotection by WR-2721 of gamma-irradiated rat parotid gland: effect on gland weight and secretion at 8-10 days post irradiation.

Changes in rat parotid salivary gland weight and functional parameters were evaluated at 8 to 10 days post irradiation in WR-2721 protected and non-protected animals following exposure to a single 15.3 Gy dose of Cs-137 radiation to the head. Glandular fluid secretory capacity was assessed by maximum flow rate, total volume of saliva and duration of secretion following pilocarpine stimulation. Protection against radiomucositis was also evaluated indirectly by daily monitoring of food and water intake, body weight and paraoral symptomatology. WR-2721 provided a significant degree of protection for all glandular functional parameters as well as gland weight. Relative protective factors (RPF) were computed for irradiated protected and non-protected animals compared to their sham-irradiated, pair-fed controls. The calculated RPFs were: Gland weight 1.9, maximum flow rate 2.9, volume of saliva 2.1 and duration of secretion 2.1 for a mean "relative protection" of 2.25. Substantial protection against radiomucositis in protected animals was evident by a progressive gain in body weight and lack of oral signs and symptoms as compared to non-protected animals. Protection against radiomucositis and preservation of residual parotid gland secretory capacity as determined by functional parameters suggests that WR-2721 may be of significant benefit in alleviating oral symptoms and maintaining salivary gland function for patients receiving radiotherapy for head and neck tumors.

Amifostine↗
PubMed1984

Oral manifestations of chronic graft-v-host disease.

Sixty patients were studied 180 to 500 days after allogeneic marrow transplantation to determine if late oral abnormalities were associated with the presence of chronic graft-v-host disease (GVHD). Lip and intraoral mucosal surfaces were evaluated for color, keratinization, atrophy, and erythema. Subjective complaints of oral pain and xerostomia were also recorded. Abnormalities were scored on a scale of 0 to 3 and tested for association with GVHD by chi 2 test. Oral manifestations most strongly associated with chronic GVHD included atrophy and erythema or lichenoid lesions of the buccal and labial mucosa and oral pain. Oral manifestations resembled several naturally occurring autoimmune disorders. Recognition of these changes can aid in the clinical diagnosis and assessment of established chronic GVHD.

Adolescent↗
PubMed1983

The predictive value of elevated labial saliva sodium concentration: its relation to labial gland pathology in bone marrow transplant recipients.

Labial minor gland salivary flow rate and sodium concentration were analyzed in relation to 1) histologic findings in labial biopsy specimens and 2) the occurrence of chronic graft-versus-host disease (GVHD) in patients who received bone marrow transplants. Biopsy specimens and samples were obtained from 61 recipients of marrow transplants (including three twins) 51 to 1,260 days post transplantation. Labial saliva sodium concentrations were elevated in some patients, and these increases were associated with inflammation and destruction of minor salivary gland acini and ducts by chronic GVHD or other factors. The predictive value of the salivary sodium changes in evaluating labial salivary gland pathologic changes was 91 per cent, and the sensitivity was 74 per cent. Thus, if a transplant recipient is found to have an elevated labial saliva sodium level, then the probability that he has pathologic labial gland changes is 91 per cent. When analyses were restricted to include only patients who received no irradiation during transplantation, then elevated labial saliva sodium concentration was significantly associated with the occurrence of chronic GVHD. The sensitivity of this relationship was 42 per cent, but the predictive value was 100 per cent. Thus, if a nonirradiated transplant recipient is found to have an elevated labial saliva sodium concentration, then it is virtually certain that he has chronic GVHD. We found no significant changes in labial saliva flow rates in these bone marrow transplant recipients.

Adolescent↗