bluuebunny/crossref_metadata_2025 huggingface dataset:
G1 cyclins in oral epithelial dysplasia
Authors: Oliver R. J. , MacDonald D. G.
Published: March 2003

Abstract: The G1 cyclins, D1, D3 and E, were investigated in 38 lesions of oral epithelial dysplasia from the floor of the mouth or the lateral border of the tongue. Their immunohistochemical expression was observed and compared with that of Ki‐67 and with the degree of dysplasia assessed by the semi‐objective technique of Smith & Pindborg. Antibody labelled cells were quantified and expressed as a percentage (LI%) of the total nucleated cell population and per mm basement membrane length (LI/mm). The labelling indices of all of the antibodies were high and quantitatively similar. There were no significant correlations with the degree of dysplasia assessed by the atypia scores. There was a correlation between labelling indices for the various antibodies expressed as LI/mm but little correlation between the indices expressed as LI%. The distribution of the D cyclins was similar to that of Ki‐67 with relatively few of the basal cells demonstrating immunoreactivity. The reasons for this are discussed in the paper. Some cross‐reactivity was observed with the cyclin antibodies. We conclude that the antibodies against the cyclins used in the present study are not a useful adjunct in the study of the cell kinetics of oral epithelial dysplasia.
The secretion of parotid saliva as stimulated by 10% citric acid is not related to precipitating factors in burning mouth syndrome
Authors: Lamey P.‐J. , Murray B. M. , Eddie S.‐A. , Freeman R. E.
Published: March 2003

Abstract: Burning mouth syndrome (BMS) is known to have multiple precipitating factors and exists in various clinical subtypes. If salivary gland function was compromised in BMS it could help explain the link with diverse precipitating factors. This study quantified stimulated right and left parotid flow rates (SPFR) in 114 patients with BMS. It also attempted to correlate SPFR with haematinic parameters, oral candidal carriage, concurrent drug therapy and BMS subtype. No relationship was found between haematinic parameters and SPFR nor between SPFR and oral candidal carriage. Patients with Type 2 BMS had a significant reduction in SPFR. Antidepressant medication was associated with reduced SPFR but there was no such association with either tranquillisers or hypnotics. These results provide evidence of reduced parotid gland function in Type 2 BMS and a role for antidepressant medication in reducing SPFR.
Cysticercosis of the oral mucosa: aspiration cytologic diagnosis
Authors: Mazhari N. J. , Kumar Neeta , Jain Shyama
Published: March 2003

Abstract: Oral mucosa is a rare site for cysticercosis. This paper describes eight cases of cysticercosis involving the oral cavity: four in the buccal mucosa, two in the lips, one in the tongue and one in the gums. All of the patients presented with a solitary superficial mucosal nodule, with duration varying from one month to three years. Larval fragments of cysticercus cellulosae on an inflammatory background were seen in cytologic smears in all cases. Diagnosis of cysticercosis was clinically unsuspected in all these cases prior to aspiration cytologic diagnosis.
A molecular epidemiological study of sequential oral isolates of Candida albicans from terminally ill patients
Authors: Wilson M. J. , Williams D. W. , Forbes M. D. L. , Finlay I. G. , Lewis M. A. O.
Published: March 2003

Abstract: The pattern of candidal colonisation was studied in a group of terminally ill patients receiving antifungal treatment for oral candidosis. A total of 43 isolates of C. albicans was collected pre‐ and post‐antifungal treatment from patients up to a maximum period of 4 weeks. Isolates were analysed by electrophoretic karyotyping (EK) and by inter‐repeat polymerase chain reaction (IR‐PCR). Fifteen electrophoretic karyotypes and 17 IR‐PCR profiles were identified. Sequential isolates from 10 patients yielded identical profiles in both EKs and IR‐PCR analyses. In the case of four patients, minor differences in the profiles were obtained by either EK or IR‐PCR. The findings suggest that antifungal treatment in this patient group fails to eradicate the original C. albicans strain, thereby allowing recolonisation of the oral cavity. The present study has also shown that either EK or IR‐PCR is a useful typing approach in such epidemiological investigations.
Atypical plexiform ameloblastoma with dentinoid: adenoid ameloblastoma with dentinoid
Authors: Matsumoto Yasuhiro , Mizoue Katsuya , Seto Kanichi
Published: March 2003

Abstract: In this study, we report a tumor that resembled previously reported uncommon tumors histologically similar to ameloblastoma or adenomatoid odontogenic tumor (AOT), showing the formation of hard tissue. We evaluated the histological characteristics by reviewing the literature. The patient was a 19‐year old male. The lesion was located from the canine to third molar in the right mandible and was unicystic with a comparatively clear demarcation. The tumor tissue was cystic overall, showing multiple formation of small and large cysts. The tumor tissue resembled a variant form of plexiform ameloblastoma. Formation of dentin and dentinoid was observed in the tumor stroma, whereas formation of enamel was not observed. Very few cases of a variant form of ameloblastoma that shows formation of dentinoid have been reported, and the histological picture in this study closely resembled previously reported “adenoid ameloblastoma with dentinoid”.
Ameloblastic fibrosarcoma of the mandible: report of two cases and review of the literature
Authors: Bregni Roman Carlos , Taylor Adalberto Mosqueda , García Abelardo Meneses
Published: March 2003

Abstract: Ameloblastic fibrosarcoma (AFS) is a rare malignant odontogenic tumour. To date, 60 well‐documented cases have been published in the English‐language literature. Two additional cases located in the posterior region of the mandible are reported. The relevant clinicopathological features of these cases, as well as those previously reported are discussed. Approximately two‐thirds of AFS are malignant tumors de novo, with an average age of the affected patients being 22.9 years. This age is lower than the one observed in AFS developing from a pre‐existent benign lesion (mean 33 years). Although regional and distant metastases are very infrequent, AFS is a locally aggressive lesion, with 23 (37%) of the reported cases having at least one recurrence; 12 patients (19.3%) died of the disease. Wide surgical excision with long‐term follow‐up remains the treatment of choice for this neoplasm.
Effects of 5 ‐fluorouracil on mitogen ‐induced costimulatory capacity of accessory cells from rat oral mucosa and dental pulp
Authors: v. Bültzingslöwen Inger , Carlsson Göran , Gustavsson Bengt , Jontell Mats
Published: March 2003

Abstract: The present study was designed to investigate the effect of the antimetabolite 5‐fluorouracil (5‐FU) on the capacity of the oral epithelium and the dental pulp to induce a mitogen‐driven T‐cell proliferation. Inbred Lewis rats were given 6 i.v. injections of 5‐FU (30 mg/kg or 50 mg/kg) over a period of 8 days. Suspensions of oral epithelial and dental pulpal cells were prepared. The costimulatory capacity of the accessory cells from treated animals was monitored by their ability to induce a mitogen (ConA)‐mediated proliferation of T cells isolated from regional lymph nodes of untreated animals. Accessory epithelial cells from rats treated with the high dose of 5‐FU, but not the low dose, induced a decreased T‐cell proliferation compared to controls. Accessory pulpal cells from rats, treated with 30 mg/kg or 50 mg/kg of 5‐FU, induced a lower T‐cell proliferation. When MHC class II molecule depleted T‐cell suspensions from lymph nodes of 5‐FU‐injected animals were incubated with ConA, a significant proliferative response was observed. This finding correlated with an increase of MHC class II molecule expressing cells detected after incubation, although no such cells were observed immediately following the initial purification step of T cells. This finding demonstrates that the accessory cells could partly restore their expression of MHC class II molecules during incubation. The results of the study suggest that the function of immunocompetent cells of the oral mucosa and dental pulp is influenced by treatment with 5‐FU and that the function of accessory cells of the pulp is affected more than the function of accessory cells derived from the oral mucosa.
Levamisole and/or Chinese medicinal herbs can modulate the serum level of squamous cell carcinoma associated antigen in patients with erosive oral lichen planus
Authors: Sun A. , Chiang C. P.
Published: March 2003

Abstract: The serum levels of squamous cell carcinoma associated antigen (SCCA) were determined by a microparticle enzyme immunoassay in a group of patients with stage I oral squamous cell carcinoma (OSCC), major or minor type erosive oral lichen planus (EOLP), recurrent aphthous stomatitis (RAS), Behçet’s disease (BD), oral leukoplakia (OL), or oral submucous fibrosis (OSF), and in normal control subjects. About 97% of the normal control subjects and the patients with minor type EOLP, RAS, BD, OL or OSF had a serum level of SCCA within the normal limit of 1.2 ng/ml. However, 6 of the 12 (50%) patients with stage I OSCC and 14 of the 31 (45.2%) patients with major type EOLP had a serum level of SCCA greater than 1.2 ng/ml. The mean serum level of SCCA in stage I OSCC patients (1.38±1.16 ng/ml) or in major type EOLP patients (1.32±1.23 ng/ml) was significantly higher than that in normal control subjects (P<0.001) and that in the patients with minor type EOLP (P<0.001), RAS (P<0.001), BD (P<0.05), OL (P<0.05), or OSF (P<0.05). Either major or minor type EOLP patients could obtain a significant mean reduction of the serum SCCA level of 0.34–0.63 ng/ml after treatment with levamisole and/or Chinese medicinal herbs for 1–30 months. Combination therapy with levamisole plus Chinese medicinal herbs could achieve a shorter duration of treatment to get complete remission than the single therapy with either levamisole only or Chinese medicinal herbs only. We conclude that levamisole and/or Chinese medicinal herbs can modulate the serum SCCA level in EOLP patients. SCCA may be a useful marker in evaluating therapeutic effects and in monitoring the disease status of EOLP. For EOLP patients, the combination therapy is superior to the single therapy of levamisole or of Chinese medicinal herbs.
Expression of inducible nitric oxide synthase and heat shock proteins in periapical inflammatory lesions
Authors: Suzuki Takahiro , Kumamoto Hiroyuki , Ooya Kiyoshi , Motegi Katsutoshi
Published: March 2003

Background:  The mechanisms responsible for activation and proliferation of lining epithelium involved in inflammatory processes in periapical inflammatory lesions remain unclear. In this study, the expression and distribution of inducible nitric oxide synthase (iNOS) and heat shock proteins (HSPs) were immunohistochemically investigated in periapical inflammatory lesions.

Methods:  Control specimens of periodontal ligaments including Malassez epithelial rests from seven teeth and periapical inflammatory lesions (15 apical granulomas (AGs), 16 radicular cysts (RCs), and 10 residual radicular cysts (RRCs)) were prepared and examined by the standard streptavidin–biotin peroxidase complex method using anti‐iNOS rabbit polyclonal antiserum, and anti‐HSP27, ‐HSP60, ‐HSP70 mouse monoclonal antibodies.

Results:  Immunoreactivity for iNOS was detected in macrophages, lymphocytes, and endothelial cells of granulation tissue and in lining epithelium of periapical inflammatory lesions. Malassez epithelial rests showed no or slight staining for iNOS. The epithelial staining intensity of iNOS in RCs was greater than that in Malassez epithelial rests and RRCs. Immunoreactivity for HSP27 was recognized in inflammatory cells, endothelial cells and lining epithelium of periapical inflammatory lesions and in Malassez epithelial rests. HSP60 was detected in some lymphocytes of granulation tissue and in lining epithelium of periapical inflammatory lesions, whereas Malassez epithelial rests showed no staining for HSP60. Epithelial HSP60 reactivity was more intense in RCs than in RRCs. HSP70 was expressed in lymphocytes, endothelial cells and lining epithelium of periapical inflammatory lesions and in Malassez epithelial rests. The staining intensity of HSP70 in Malassez epithelial rests was slightly lower than that in lining epithelium of RCs and RRCs.

Conclusions:  These data demonstrate that the expressions of iNOS, HSP60, and HSP70 are involved in inflammatory processes and might play a role in the activation and proliferation of lining epithelium, leading to progression of periapical inflammatory lesions.
Usefulness of AgNOR counts in diagnosing epithelial dysplasia
Authors: Ray Jay G. , Chattopadhyay Amit , Caplan Daniel J.
Published: March 2003

Background:  Diagnosis of epithelial dysplasia has traditionally been subjective, and there is a need for a quantifiable and useful test.

Methods:  In a double blind study, clinical leukoplakias from 52 people were diagnosed for presence (DLK) or absence (NDLK) of epithelial dysplasia using hematoxylin and eosin (H&E) stain as a gold standard criterion, and results were compared against their mean silver stainable nucleolar organizer region (AgNOR) counts. We used mean AgNOR count cut‐point of 2.37 from our prior report as the diagnostic threshold (mean ≥ 2.37 being DLK and mean < 2.37 being NDLK).

Results:  The two methods (H&E and AgNOR) disagreed in 37% of the diagnoses. Both NDLK and DLK had high AgNOR counts. P‐AgNOR was non‐contributory for diagnosing epithelial dysplasia.

Conclusions:  Mean AgNOR count can be a useful tool in definitive diagnosis of epithelial dysplasia.
Laminin‐5 gamma 2 chain is colocalized with gelatinase‐A (MMP‐2) and collagenase‐3 (MMP‐13) in odontogenic keratocysts
Authors: Wahlgren Jaana , Väänänen Anu , Teronen Olli , Sorsa Timo , Pirilä Emma , Hietanen Jarkko , Maisi Päivi , Tjäderhane Leo , Salo Tuula
Published: March 2003

Background:  Odontogenic keratocyst (KC) differs from other epithelial odontogenic cysts in regard to increased epithelial proliferation and a strong tendency to recur. Laminin‐5 (Ln‐5) is an epithelial anchoring filament component, which after modulation by certain matrix metalloproteinases (MMPs), like MMP‐2 and MMP‐13, induces epithelial cell migration.

Methods:  Using in situ hybridization and immunohistochemistry, we studied the Ln‐5 gamma‐2 chain expression related to the expression of MMP‐2, ‐8, and ‐13 in different odontogenic cysts, including radicular cysts (RC; n = 11), follicular cysts (FC; n = 11), and odontogenic keratocysts (KC; n = 16).

Results:  Ln‐5 mRNA was present in all cysts examined, while less than half of KCs and RCs (33 and 40%, respectively) demonstrated MMP‐2 mRNA. MMP‐13 mRNA was present in all KC samples. Ln‐5 protein was located as a continuous ribbon in BM zone of all KCs, and MMP‐2 and MMP‐13 immunoreactivities colocated significantly with Ln‐5 in that area. MMP‐8 was expressed by stromal macrophages and epithelial goblet cells, but never located in BM zone.

Conclusions:  Our results indicate that the colocalization of Ln‐5 with MMP‐2 or MMP‐13, but not with MMP‐8, in BM zone of KCs, may be related to special characteristics of KC.
Inverse Correlation Between Pink‐Eyed Dilution Protein Expression and Induction of Melanogenesis by Bafilomycin A1
Authors: MANGA PRASHIELA , ORLOW SETH J.
Published: March 2003

The pink‐eyed dilution protein (p) plays a pivotal role in the synthesis of eumelanin. In its absence, critical melanosomal proteins fail to traffic to the melanosome. Pink‐eyed dilution gene (P) mutations are the most common cause of tyrosinase‐positive oculocutaneous albinism worldwide. Thus, reports that bafilomycin A1 was able to induce synthesis of melanin in tyrosinase‐positive melanomas led us to test the drug on p‐null murine melanocytes. We found that in melanocytes lacking p, bafilomycin A1 was able to induce melanin synthesis. These cells, once transfected with an expression vector encoding an epitope‐tagged p transcript, failed to respond to the drug. The increase in melanin synthesis is accompanied by a reduction in tyrosinase protein cleavage and secretion with subsequent accumulation within the melanocyte. Bafilomycin A1 has also been reported to induce pigmentation of normal Caucasian melanocytes. Based on these data we hypothesize that p may serve as a key control point at which ethnic skin color variation is determined.
‘VIT1’, A Novel Gene Associated with Vitiligo
Authors: Le Poole I. Caroline , Sarangarajan Rangaprasad , Zhao Yang , Stennett Lawrence S. , Brown Thomas L. , Sheth Pranav , Miki Toru , Boissy Raymond E.
Published: March 2003

To define genes associated with the pigmentary disorder vitiligo, gene expression was compared in non‐lesional melanocytes cultured from three vitiligo patients and from three control melanocyte cultures by differential display. A basic local alignment search tool search did not reveal homology of six differentially expressed cDNA fragments to previously identified expressed sequence tags; thus, one was used to screen a melanocyte cDNA library. The underlying VIT1 gene maps to chromosome 2p16. The 3′ portion of the VIT1 message is complementary to the 3′ end of hMSH6 mRNA, enabling the formation of RNA–RNA hybrids, which may interfere with G/T mismatch repair function. Moreover, the aligned cDNA sequence revealed an open reading frame identical to a hypothetical protein expressed in brain, with a similarity to Drosophila calmodulin, and containing a zinc‐finger motif partially identical to N‐recognin. Expression of ORF mRNA was confirmed for multiple skin cell types, suggesting its importance for skin physiology.
Comparing Quantitative Measures of Erythema, Pigmentation and Skin Response using Reflectometry
Authors: Wagner Jennifer K. , Jovel Celina , Norton Heather L. , Parra Esteban J. , Shriver Mark D.
Published: March 2003

We measured a number of pigmentation and skin response phenotypes in a sample of volunteers (n=397) living in State College, PA. The majority of this sample was composed of four groups based on stated ancestry: African‐American, European‐American, Hispanic and East Asian. Several measures of melanin concentration (L*, melanin index and adjusted melanin index) were estimated by diffuse reflectance spectroscopy and compared. The efficacy of these measures for assessing constitutive pigmentation and melanogenic dose–response was evaluated. Similarly, several measures of erythema (a*, erythema index and adjusted erythema index) were compared and evaluated in their efficacy in measuring erythema and erythemal dose–response. We show a high correspondence among all of the measures for the assessment of constitutive pigmentation and baseline erythema. However, our results demonstrate that evaluating melanogenic dose–response is highly dependent on the summary statistic used: while L* is a valid measure of constitutive pigmentation it is not an effective measure of melanogenic dose–response. Our results also confirm the use of a*, as it is shown to be highly correlated with the adjusted erythema index, a more advanced measure of erythema based on the apparent absorbance. Diffuse reflectance spectroscopy can be used to quantify the constitutive pigmentation, melanogenic dose–response at 7 d and erythemal dose–response at both 24 h and 7 d postexposure.
Regulation of the Human Melanocortin 1 Receptor Expression in Epidermal Melanocytes by Paracrine and Endocrine Factors and by Ultraviolet Radiation
Authors: Scott M. Cathy , Suzuki Itaru , Abdel‐Malek Zalfa A.
Published: March 2003

The aim of this study is to investigate the regulation of the human melanocortin 1 receptor (MC1R) expression in cultured normal human melanocytes (NHM) by specific paracrine and endocrine factors, and by ultraviolet radiation (UVR). Treatment of NHM with α‐melanotropin [α‐melanocyte stimulating hormone (α‐MSH)] increased MC1R mRNA level; the response was often more pronounced in NHM with a low (NHM‐c) than in NHM with a high melanin content (NHM‐b). Endothelin‐1 increased MC1R mRNA level in NHM regardless of their melanin content. Basic fibroblast growth factor consistently up regulated MC1R mRNA level in NHM‐b but not in NHM‐c. Activation of protein kinase C by 12‐0‐tetradecanoylphorbol‐13‐acetate slightly increased, while stimulation of adenylate cyclase by forskolin markedly up‐regulated the MC1R mRNA level. β‐Estradiol increased, and combined treatment with β‐estradiol and α‐MSH further elevated, MC1R mRNA level in NHM‐c and NHM‐b. Testosterone reduced, while progesterone had no effect on, MC1R mRNA level. Agouti signaling protein reduced, and UVR down regulated dose‐dependently MC1R mRNA level in NHM‐b and NHM‐c. This effect was reversed 24 h after irradiation with the lower doses of 7 or 14 mJ/cm2, but not after exposure to a higher, more cytotoxic dose of UVR. We conclude that the MC1R is regulated by paracrine factors, including its own ligands, by specific endocrine sex hormones, and by UVR. Differences in the responses of NHM to some of these factors suggest differential regulation of MC1R gene expression, which may contribute to the variation in constitutive and UV‐induced cutaneous pigmentation in humans.
The Impact of Epidermal Melanin on Objective Measurements of Human Skin Colour
Authors: Alaluf Simon , Atkins Derek , Barrett Karen , Blount Margaret , Carter Nik , Heath Alan
Published: March 2003

Objective measurements of human skin colour were made with a tristimulus (L*a*b*) chromameter in a range of different ethnic skin types. These were compared with biochemical measurements of melanin content, melanin composition and melanosome size in skin biopsies obtained from the same sites. L*, a* and b* values were found to vary significantly with ethnicity. In general, constitutively dark skin types have lower L* values, higher a* values and higher b* values than constitutively light skin types. Total epidermal melanin content appears to be the primary determinant of L* values in human skin (r=−0.88; P < 0.00001), whilst melanosome size also has a significant but more subtle influence on L* values (r=−0.73; P < 0.00001). There is also a strong positive contribution to a* values from epidermal melanin (r=0.66, P < 0.00001), which accounts for the ethnic variation in a* values observed in this study. Melanin is also a major contributor to b* values in lighter skin types (r=0.71, P < 0.00001). However, this relationship breaks down in darker skin types where b* values actually reach a maximum and then decrease as the concentration of melanin in the skin increases. This appears to be because of optical masking of yellow light by high concentrations of melanin in the epidermis. Analysis of the relationships between L*, a* and b* values in human skin indicate that they are very closely interrelated, and suggest that the optical properties of melanin in the epidermis are very similar to those of a dye on a fabric substrate.
Melanosomal Proteins – Role in Melanin Polymerization
Authors: Sharma Savitha , Wagh Sushama , Govindarajan Raman
Published: March 2003

Melanin, the major determinant of skin colour, is a tyrosine‐based heteropolymer of indeterminate molecular weight. In vivo, melanin synthesis occurs within highly specialized organelles called melanosomes. Coated vesicles encapsulating the enzyme tyrosinase and tyrosinase related proteins, fuse with premelanosomes that contain structural proteins to form mature melanosomes. Coated vesicles and premelanosomes have been shown to have only melanin monomers but not the polymer. Our earlier results have clearly shown that the presence of proteins other than tyrosinase are critical for the post‐tyrosinase steps of melanin polymerization at acidic pH. Proteins in melanosomes are difficult to purify because of their firm association with melanin. Thus, with progressive melanization, melanoproteins become progressively insoluble. In this paper, we discuss the isolation and purification of melanosomal proteins and their role in melanin polymerization. We have hypothesized that the initiation of polymerization and the binding of melanin to proteins are two discrete events and we have developed assays to quantify these events. Purified melanosomal proteins differ in their ability to polymerize melanin monomers. Further, we have also shown that two polypeptides (28 and 45 kDa) purified from melanosomes inhibit melanin polymerization but can bind preformed melanin. In conclusion, melanosomal proteins regulate melanin polymerization and differ in their ability to bind melanin. Polymerization and binding abilities of melanosomal proteins are specific to each protein and melanin–protein interaction is not nonspecific.
Effects of Melanogenesis‐Inducing Nitric Oxide and Histamine on the Production of Eumelanin and Pheomelanin in Cultured Human Melanocytes
Authors: Lassalle Michael W. , Igarashi Shigeru , Sasaki Minoru , Wakamatsu Kazumasa , Ito Shosuke , Horikoshi Toshio
Published: March 2003

Melanin pigments produced in human melanocytes are classified into two categories; black coloured eumelanin and reddish‐yellow pheomelanin. Stimulation of melanocytes with α‐melanocyte‐stimulating hormone (α‐MSH), one of several melanogenic factors, has been reported to enhance eumelanogenesis to a greater degree than pheomelanogenesis, which contributes to hyperpigmentation in skin. Nitric oxide (NO) and histamine are also melanogenesis‐stimulating factors that are released from cells surrounding melanocytes following ultraviolet (UV) irradiation. In this study, the effects of NO and histamine on the ratio of eumelanin and pheomelanin were examined in human melanocytes, and then compared with that of α‐MSH. The amounts of eumelanin and pheomelanin were quantified using high‐performance liquid chromatography analysis after oxidation and hydrolysis of melanin. Melanogenesis was induced by the addition of α‐MSH, NO, or histamine to melanocytes. The amount of eumelanin production significantly increased with independent stimulation by these melanogenic factors, especially histamine, while that of pheomelanin significantly increased with α‐MSH and NO, but only slightly with histamine. As a result, the ratio of eumelanin and pheomelanin increased significantly with the addition of NO or histamine. These results suggest that NO and histamine, as in the case of α‐MSH, may contribute to UV‐induced hyperpigmentation by enhancing eumelanogenesis.
Prostaglandin F2α upregulates interleukin‐6 production in human gingival fibroblasts
Authors: Noguchi Kazuyuki , Endo Hirahito , Kondo Hirofumi , Ishikawa Isao
Published: March 2003

Prostaglandin F2α(PGF2α) is a bioactive lipid mediator which has been suggested to be involved in the pathogenesis of periodontal disease. However, the roles of PGF2α in periodontal lesions are poorly understood. In the present study, we investigated the effect of PGF2α on interleukin (IL)‐6 production in human gingival fibroblasts (HGF). PGF2αstimulated IL‐6 production in a time‐ and concentration‐dependent fashion. IL‐1β and tumor necrosis factor α(TNFα), proinflammatory cytokines, induced IL‐6 production in a time‐dependent manner, and PGF2αsynergistically enhanced IL‐6 production induced by IL‐1β and TNFα. IL‐6 mRNA was expressed in PGF2α‐stimulated HGF, and PGF2α increased IL‐6 mRNA levels induced by IL‐1β and TNFα. Fluprostenol, a selective FP receptor agonist, could mimic PGF2α‐induced IL‐6 production. Since FP receptors are coupled to elevation of intracellular calcium and activation of protein kinase C (PKC), the mechanism of IL‐6 production by PGF2α was investigated using TMB‐8, an inhibitor of Ca2+ mobilization from intracellular stores, and calphostin C, an inhibitor of PKC. TMB‐8 significantly suppressed PGF2α‐induced IL‐6 production, whereas calphostin C showed a stimulatory effect on PGF2α‐induced IL‐6 production. From these data, we suggest that PGF2α upregulates IL‐6 production through FP receptors in HGF, that PGF2α synergistically enhances IL‐6 production in IL‐1β‐ and TNFα‐stimulated HGF, and that PGF2α‐induced IL‐6 production may be dependent on intracellular Ca2+ mobilization and be downregulated by PKC activation. PGF2α may be involved in the pathogenesis of periodontal disease by enhancing IL‐6 levels in periodontal lesions.
Antimicrobial activity of silver nitrate against periodontal pathogens
Authors: Spacciapoli Peter , Buxton Debra , Rothstein David , Friden Phillip
Published: March 2003

Metal ions were evaluated as potential antimicrobial agents suitable for local delivery in the oral cavity for the treatment of periodontitis. Silver nitrate, copper chloride, and zinc chloride were tested for antimicrobial activity in in vitro killing assays conducted in phosphate buffered saline with a series of oral bacteria including gram‐negative periodontal pathogens and gram‐positive streptococci. Copper and zinc salts failed to exhibit strong and consistent activity against periodontal pathogens. In contrast, silver at a concentration of 0.5 μg/mL produced a 3 log10 reduction in colony forming units Spacciapoli/mL or greater against all periodontal pathogens tested including Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Bacteroides forsythus, Fusobacterium nucleatum vincentii, Campylobacter gracilis, Campylobacter rectus, Eikenella corrodens, and Actinobacillus actinomycetemcomitans. In comparison, substantially higher concentrations of silver nitrate failed to kill oral streptococci. A silver nitrate concentration of 25 μg/mL produced log10 reductions in CFU/mL of 3.5–5 in killing assays performed in human serum against P. gingivalis, demonstrating the ability of silver to retain activity in a biological medium similar to that encountered in vivo in the periodontal pocket. These results identify silver nitrate, an antimicrobial that may possess advantages over traditional antibiotics, as a potential agent for controlled release local delivery in the oral cavity for the treatment of periodontitis.
Elevated mRNA expression for supervillin and vascular endothelial growth factor in human neutrophils stimulated with lipopolysaccharide from Porphyromonas gingivalis
Authors: Morozumi Toshiya , Kubota Takehiko , Sugita Noriko , Ohsawa Yutaka , Yamazaki Kazuhisa , Yoshie Hiromasa
Published: March 2003

Differential gene expression was examined in human neutrophils stimulated with lipopolysaccharide from Porphyromonas gingivalis (P. gingivalis‐LPS) using RNA fingerprinting by arbitrarily primed polymerase chain reaction (RAP‐PCR). LPS from Escherichia coli (E. coli‐LPS) was used as control. More than 200 differently expressed transcripts were found in 8 subjects showing differential regulation at the transcriptional level. Densitometric analyses revealed that 42–100 genes were upregulated, while 53–116 genes were downregulated by P. gingivalis‐LPS compared with E. coli‐LPS. The results of sequencing identification showed the presence of supervillin (SVIL) and vascular endothelial growth factor (VEGF) genes in the clones which were upregulated by P. gingivalis‐LPS. Consequently, semiquantitative analyses proved that the level of mRNA for SVIL and VEGF were significantly higher in P. gingivalis‐LPS‐stimulated neutrophils than in other bacterial (E. coli, Actinobacillus actinomycetemcomitans, Prevotella intermedia) LPS‐ or synthetic lipid A‐stimulated neutrophils. Our findings suggest that an elevated mRNA expression for SVIL could be associated with impaired function of neutrophils when stimulated by P. gingivalis‐LPS. Further, the VEGF mRNA over‐expression might be related to the pathogenesis of P. gingivalis‐associated periodontitis. The RAP‐PCR technique used in this study enabled us to identify a number of P. gingivalis‐LPS regulated genes which hitherto have not been reported.
Genetic polymorphism of the tumor necrosis factor (TNF)‐α promoter region in families with localized early‐onset periodontitis
Authors: Shapira Lior , Stabholz Ayala , Rieckmann Peter , Kruse Niels
Published: March 2003

Tumor necrosis factor (TNF)‐α is a potent proinflammatory cytokine that is able to induce tissue destruction and bone resorption. A G‐to‐A polymorphism at the −308 position of the TNF‐α promoter region was suggested to influence TNF‐α production. We had previously shown that monocytes of patients with localized early‐onset periodontitis (EOP) secrete high levels of TNF‐α compared to matched controls. The aim of the present study was to investigate the possible link between the −308 polymorphism in the TNF‐α gene and EOP. Genomic DNA was extracted from the blood of 64 individuals from 11 nuclear families with EOP. The TNF‐α polymorphism at −308 was assessed using allele‐specific polymerase chain reaction. 77% of the tested adolescents were found to have the G/G genotype, and 23% had the A/G genotype. In the diseased subjects, 81% were with G/G genotype and 19% with A/G genotype. The healthy children had 74% G/G genotype, while 26% had A/G genotype. The differences between the disease group and the healthy group were not statistically significant. In summary, the present results could not demonstrate any link between EOP and genetic polymorphism in the −308 position of the TNF‐α promoter.
Upregulation of matrix metalloproteinase‐1 production by prostaglandin F2α in human gingival fibroblasts
Authors: Noguchi Kazuyuki , Tominaga Yumiko , Matsushita Kenji , Izumi Yuichi , Endo Hirahito , Kondo Hirobumi , Ishikawa Isao
Published: March 2003

In the present study, we investigated the effect of prostglandin F2α(PGF2α) and combination of PGF2α and interleukin(IL)‐1β on matrix metalloproteinase (MMP)‐1 production in human gingival fibroblasts (HGF). PGF2α enhanced MMP‐1 production in a dose‐dependent manner in HGF. Combination of PGF2α and IL‐1β induced a synergistic increase of MMP‐1 production in HGF. Furthermore, fluprostenol, a specific FP receptor agonist, increased MMP‐1 production and induced a synergistic enhancement of IL‐1β‐induced MMP‐1 production in HGF, similar to PGF2α. FP receptor mRNA expression was detected in HGF, by reverse transcription‐polymerase chain reaction. Northern blot analysis revealed that PGF2α enhanced MMP‐1 mRNA expression in HGF and that PGF2α increased MMP‐1 mRNA levels induced by IL‐1β. In conclusion, we suggest that PGF2α increases MMP‐1 production in HGF and synergistically enhances MMP‐1 production in IL‐1β‐stimulated HGF. PGF2α may be involved in degradation of connective tissue in periodontal lesions.
Peri‐implant bone regeneration using recombinant human bone morphogenetic protein‐2 in a canine model: a dose‐response study
Authors: Tatakis Dimitris N. , Koh Alexander , Jin Lisa , Wozney John M. , Rohrer Michael D. , Wikesjö Ulf M. E.
Published: March 2003

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) dose on alveolar ridge augmentation and dental implant osseointegration. Bilateral, 5 mm supraalveolar, peri‐implant defects were surgically created in 6 beagle dogs. rhBMP‐2 (0.05, 0.1 or 0.2 mg/ml) in an absorbable collagen sponge (ACS) carrier was molded around the fixtures and wounds were closed. Treatment variations were alternated between animals (incomplete block design). Animals were sacrificed at week 8 postsurgery. Nine of twelve jaw quadrants healed uneventfully. Two jaw quadrants exhibited wound failure by week 4 and one by week 8 postsurgery. Radiographic bone regeneration was observed in defects without wound failure from week 4 postsurgery. Radiolucent voids of variable size and shape were observed and regressed over time. In weeks 6 through 8, there was an apparent increase in bone density and trabecular structure, while bone height and volume decreased. Histometric analysis revealed limited differences in bone regeneration between experimental conditions. Bone regeneration area averaged (±SD) 1.0±0.5, 3.5± 1.4 and 2.3±0.4 mm2 for the 0.05, 0.1 and 0.2 mg/ml dose, respectively. There were no significant differences in osseointegration. Osseointegration in newly formed bone averaged 19± 4%, 18± 10% and 21±6% for the 0.05, 0.1 and 0.2 mg/ml rhBMP‐2 sites, respectively. Collectively, the data suggest that there are no dramatic differences in bone induction and osseointegration within the selected dose and observation interval.
Inhibition of alveolar bone loss by matrix metalloproteinase inhibitors in exjreimental jreiodontal disease
Authors: Ramamurthy Nungavaram S. , Xu Jing‐wen , Bird John , Baxter Andrew , Bhogal Ranjev , Wills Ruth , Watson Bob , Owen David , Wolff Mark , Greenwald Robert A.
Published: March 2003

Jreiodontal disease is characterized by excessive host collagenase resulting in loss of gingival and jreiodontal ligament collagen and adjacent alveolar bone. Intragingival endotoxin injection induces a model of jreiodontal disease characterized by rapid bone loss with biochemical features similar to that of naturally occurring adult jreiodontitis. CH1766, a peptide with a zinc binding moeity which fits into the active site of the enzyme, and CH6631, a hydroxamic acid derivative with aryl‐substituted sulphonamide residues, are inhibitors of matrix metalloproteinases (MMPIs) with differing inhibitory profiles as characterized by in vitro assays. In this study, endotoxin was injected into the gingivae of rats which were then treated orally with either 3 mg/kg or 30 mg/kg of one of the two inhibitory compounds. The gingival tissues were assessed for collagenase and gelatinase activity, plus three different pro‐inflammatory cytokines. In addition, alveolar bone height in defleshed jaws was studied by computerized morphometric analysis and scanning electron microscopy. Both drugs reduced active and/or total MMP activity, in many cases to normal, and also partially normalized cytokine levels as well. A dose‐response effect was seen with regard to amelioration of lipopolysaccharide‐induced alveolar bone loss with both drugs. Other than studies with tetracyclines, this is the first report of beneficial effects of MMPIs in a model of jreiodontal disease, strongly suggesting that this class of agents could bring therapeutic benefit to patients with this disorder, and that jreiodontal disease can be used as a model to demonstrate in vivo efficacy of this class of drugs.
Treatment with SRL172 (heat‐killed Mycobacterium vaccae) inhibits progression of established experimental periodontal disease in Wistar rats
Authors: Breivik Torbjørn , Rook Graham A. W.
Published: March 2003

Periodontal disease is accompanied by a change in the periodontal bacterial flora, and an increase in Th2 cytokine expression. Therefore, preparations that can down‐regulate Th2 responses and increase Th1 responses to bacteria may have therapeutic effects. SRL172, a preparation of heat‐killed Mycobacterium vaccae (NCTC 11659), has been shown to have these properties in man and animals and, in a previous study, a single subcutaneous injection of this material 13 days before application of ligatures to the right second molars of Wistar rats strikingly reduced subsequent destruction of the tooth‐supporting tissues. The same material has therefore been tested in a therapeutic protocol, in rats with ongoing periodontal disease. A silk ligature was placed round the maxillary right second molar in the gingival sulcus on day 0. This was removed after two weeks, and the animals immediately received 0.1 mg SRL172 s.c. or saline. One week later (i.e. at three weeks), a boost of 1.0 mg SRL172 or saline was given. Animals were sacrificed at eight weeks (i.e. five weeks after the booster dose). Treatment of ongoing periodontal disease with SRL172 significantly reduced fibre loss (p = 0.046 by histometry) and bone loss (p = 0.0008 by radiography) on the ligatured side, and reduced fibre loss (p = 0.0086) on the control side. Thus SRL172 is an effective treatment in this model. As SRL172 has undergone extensive safety testing in man, these results justify clinical studies in periodontal disease, and such studies are now planned.
Effects of interleukin‐4 on proteoglycan accumulation in human gingival fibroblasts
Authors: Hashimoto‐Uoshima M. , Noguchi K. , Suzuki M. , Murata A. , Yanagishita M. , Ishikawa I.
Published: March 2003

In inflammatory gingival diseases, cytokines have been demonstrated to play critical roles by coordinating the stimulation of immunological and connective tissue cells. The activities of these cells, degrading and remodeling extracellular matrices, constitute the major pathological and repair processes. Thus, elucidating cellular and molecular events occurring in inflamed connective tissues is crucial for the understanding and treatment of inflammation. In order to test a hypothesis that proinflammatory cytokines affect metabolism of major extracellular matrix molecules, we studied metabolism of proteoglycans (PGs) by human gingival fibroblasts (HGF) under the influence of interleukin‐4 (IL‐4) as a model of gingivitis. HGF in cell culture were metabolically radiolabeled using [3H]glucosamine and [35S]sulfate in the presence or absence of IL‐4, and the labeled PGs were analyzed by chromatographic techniques. The incorporation of 35S into PGs increased with IL‐4 both in media and cell layer. At 100 ng/ml of IL‐4, the increment of 35S incorporation over control culture was 16–39% (p<0.001) in media and 12–35% (p=0.01) in cell layer. The 35S‐labeled macromolecules were PGs containing heparan sulfate (HS) and chondroitin sulfate (CS) chains. From the molecular weight and glycosaminoglycan composition analyses, versican and jrelecan‐type and biglycan and decorin‐type were very likely to be the major PG constituents both in media and cell layer. IL‐4 stimulated synthesis of versican and jrelecan‐type more potently than biglycan and decorin‐type. With IL‐4 treatment, the ratio of CSPG/HSPG decreased in media and increased in cell layer. This ratio suggested that syndecan family HSPGs were also present in HGF. In conclusion, IL‐4 stimulated accumulation of CS/HSPGs in human gingival fibroblasts.
The effect of chronic emotional stress on the humoral immune response to Porphyromonas gingivalis in mice
Authors: Houri‐Haddad Yael , Itzchaki Oded , Ben‐Nathan David , Shapira Lior
Published: March 2003

Previous studies have shown that psychological stress plays a significant role in the outcome of infectious diseases, but data related to the effect of stress on periodontal infection is limited. The present study was designed to test the impact of emotional stress on the humoral immune response to the periodontal pathogen Porphyromonas gingivalis in a mouse model of local inflammation. Chambers constructed from titanium wire were implanted in the subcutaneous dorsolumbar region of mice. All mice were immunized with P. gingivalis followed by an intrachamber challenge with the bacteria. One group of mice was used as control, while the other two experienced experimental stress conditions (isolation/restraint stress). Stress‐1 group was stressed during the immunization period, while Stress‐2 group was stressed during the local challenge period. Chamber exudates and serum were collected and analyzed for levels of anti‐P. gingivalis antibodies (IgG, IgG1 and IgG2a). The levels of serum antibodies to P. gingivalis were not different between the three tested groups, excluding increased levels of IgG2a in Stress‐1 group at baseline. The levels of antibodies in the chamber exudates were significantly lower in the stressed groups at baseline, but higher at d 7. The IgG1 to IgG2a ratio was significantly higher in the control group compared with the two stressed groups. The findings of the present study suggest that chronic psychological stress had a marked impact on the localized response to P. gingivalis challenge. The lower IgG1/IgG2a ratio observed in the stress groups suggests elevated Th1 response during stress.
Relevance of Multidrug Resistance Proteins for Intestinal Drug Absorption in vitro and in vivo
Authors: Fricker Gert , Miller David S.
Published: March 2003

Abstract: Multidrug resistance proteins (p‐glycoprotein and mrps) are becoming increasingly important to explain the pharmacokinetics and action of drugs. Located in epithelial and endothelial cells of the gastrointestinal tract, liver, kidney, blood brain barrier, choroid plexus and other organs, they are critical determinants for the movement of a large number of commonly prescribed drugs across cellular barriers. Here we provide a brief overview of the role of multidrug resistance proteins in drug absorption from the gastrointestinal tract. We address the different types of multidrug resistance proteins involved, describe experimental models to study the influence of these proteins on transcellular transport and discuss the impact of multidrug resistance proteins on overall drug bioavailability in vivo.
Generation of Hydroxyl Radicals Mediated by Streptozotocin in Pancreatic Islets of Mice in vitro
Authors: Gille Lars , Schott‐Ohly Patricia , Friesen Nadira , Schulte im Walde Sabine , Udilova Natascha , Nohl Hans , Gleichmann Helga
Published: March 2003

Abstract: Type I diabetes is considered a multifactorial autoimmune process initiated by an environmental factor. There is evidence that reactive oxygen species are involved in destructing insulin‐producing β‐cells. In mice, reactive oxygen species and nitric monoxide contribute to β‐cell damage in the non‐obese diabetic strain developing spontaneously diabetes and in diabetes induced with multiple low doses of streptozotocin. Previously, we found that zinc sulfate induced metallothionein in pancreatic islets, protected β‐cells against streptozotocin toxicity in vitro, and prevented diabetes induced with multiple low doses of streptozotocin. Since metallothionein is known to scavenge hydroxyl radicals in cell‐free systems, we hypothesize that the protective effect of zinc sulfate results from metallothionein induction scavenging hydroxyl radicals generated by multiple low doses of streptozotocin. Therefore, we studied whether levels of hydroxyl radicals are increased by streptozotocin in isolated islets in vitro. Here, we demonstrate basal and streptozotocin‐stimulated hydroxyl radicals by electron spin resonance spectroscopy in combination with hydroxyl radical‐specific spin trapping in islet homogenates. Furthermore, in islet cultures, streptozotocin augmented generation of reactive oxygen species as determined by fluorescence. Of the group of reactive oxygen species, the streptozotocin‐augmented generation of hydrogen peroxide was also specifically determined. We conclude that streptozotocin‐mediated hydroxyl radicals and generation of reactive oxygen species may be crucial effectors in β‐cell damage.