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Biomedical subjects

L M Lin

Publications and source records attributed to L M Lin.

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

Primary oral squamous cell carcinoma: an analysis of 703 cases in southern Taiwan.

We retrospectively analyzed the records of 703 cases of oral squamous cell carcinoma (SCC) collected from 1 January 1985 to 31 December 1996 at a teaching hospital in southern Taiwan, to identify the characteristics of patients and factors associated with survival. There was an overwhelming male predominance (male:female = 15:1). The mean age of the patients was 52. The peak age of oral SCC patients declined from 50 to 59 years in the first six years (1985-1990) and 40-49 years in the last six years (1991-1996). The most common site of oral SCC was the buccal mucosa with 263 patients (37.4%). Most patients (346/703 patients; 49.2%) had stage III cancer. The most common site of occurrence of SCC was the buccal mucosa (263/703 patients; 37.4%), both overall and in patients who chewed betel quid alone or in combination with cigarette smoking and/or alcohol consumption; the tongue was the most common site among patients without any oral habits (18/48 patients; 37.5%). Furthermore, the age of occurrence was on average 6-12 years younger among patients who chewed betel quid than in those who did not. Of the 703 patients, 496 received treatment with surgery, chemotherapy, and/or radiation therapy. Of these, 209 (42.1%) died. The cancer stage significantly influenced mortality: the 5-year survival rate in patients treated from 1985 to 1991 was 72% in those with stage I, 38.9% in those with stage II, 26.7% in those with stage III, and 11.8% in those with stage IV cancer. Six variables were found to significantly affect survival: tumor size, lymph node involvement, surgery, betel quid chewing, staging, and histological differentiation (all p < 0.05, Kaplan-Meier analysis with log rank test). Of these, surgery and cancer stage independently affected survival in a proportional hazards model (both p < 0.0001). Therefore, the early surgical intervention, and the withdrawal from oral habits, especially betel quid chewing, will be advantageous to patients' survival.

Adolescent↗
PubMed1999

Adenomatoid hyperplasia in the mandibular retromolar area. Case report.

This paper reports a case of adenomatoid hyperplasia of minor salivary glands in the retromolar area, with a unique symptom of painful swelling. This appears to be the first reported case in the Chinese population. It would be useful for clinical dentists to be aware of this tumour.

Diagnosis, Differential↗
PubMed1999

Ethnic dental analysis of shovel and Carabelli's traits in a Chinese population.

Chinese populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the association between the shovel and the Carabelli's traits in a Chinese population. The research design investigated a Chinese population that resides in southern Taiwan. The ancestors of this Chinese population migrated to Taiwan from mainland China, mainly from Fukien and Kwangtung. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After controlling for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of five and a half, which is a significant effect.

Adolescent↗
PubMed1998

Placental glutathione S-transferase isoenzyme expression in polycyclic aromatic hydrocarbon-induced hamster buccal pouch mucosa.

Placental glutathione S-transferase (GST-P) immunohistochemical activity in polycyclic aromatic hydrocarbon (PAH)-induced hamster buccal pouch mucosa (HBPM) was investigated. Equimolar concentrations of 3,4-benzo[a]pyrene (BP), benz[a]anthracene (BA) and 20-methylcholanthrene (MC) in mineral oil solution were applied three times per week for up to 20 weeks to bilateral pouches of the hamsters. Control pouches were treated with 7,12-dimethylbenz[a]anthracene (DMBA), turpentine and mineral oil, respectively. A significant increase in the number of GST-P foci in the dysplastic pouches was found when compared with the hyperkeratotic and hyperplastic pouches after 5 weeks' DMBA treatment. The average numbers of GST-P positive stainings were significantly higher in DMBA-treated groups than in BP-, BA- and MC-treated groups killed at 5, 20, 30 and 40 weeks. No GST-P positivity was found in any pouches treated with turpentine and mineral oil observed at various periods. These results highlight the carcinogen-specificity of GST-P chemically induced in HBPM and indicate that induction of GST-P in pouch mucosa is linked with the carcinogenic potency of PAHs. The present study underpins the hypothesis that GST-P chemically induced in HBPM is an early marker of ongoing squamous cell carcinogenesis.

Animals↗
PubMed1998

Osseous choristoma of oral cavity--report of two cases and review of the literature.

Osseous choristoma of the oral cavity is an extremely rare lesion. Two cases of osseous choristomas of oral cavity, representing two different natures of such lesions are reported. One was situated on the dorsal surface of posterior tongue just anterior to the circumvallate papillae and the other on the right buccal mucosa just below the orifice of the Stensen's duct. To date, about 73 cases of oral osseous choristoma have been reported in the literature including the two present cases, of which, 61 and 8 cases occurred in the tongue and buccal mucosa, respectively. The clinical and microscopic characteristics, and their common sites of these peculiar lesions are presented. The origin and pathogenesis of the lesion are discussed and the literature on the subject is reviewed.

Adult↗
PubMed1997

Evaluation of glutathione S-transferase activity in human buccal epithelial dysplasias and squamous cell carcinomas.

Glutathione S-transferase (GST) activity and amount of GST alpha, mu and pi isoforms were measured in 40 patients with histopathologically confirmed oral epithelial dysplasia (OED) and squamous cell carcinoma of buccal mucosa. The results were compared with those of normal mucosa in an equal number of age- and sex-matched healthy controls. Mean total GST activities were significantly elevated from normal buccal mucosa for mild OED, moderate OED, severe OED and squamous cell carcinoma. GST activity of value approximating 100 nmol/min/mg distinguished between normal and dysplasia, and of value about 400 nmol/min/mg delineated between dysplasia and squamous cell carcinoma were observed. GST pi was the predominant class in both the diseased and normal buccal mucosa examined. This class pi GST was present at an intracellular concentration, which was significantly higher in diseased buccal mucosa than in normal buccal mucosa. These results indicated that pi class GST was the major form of this enzyme in the cytosolic fraction of oral mucosa. The severity of OED related to squamous cell carcinoma development seemed to increase concomitantly with an increase in the level of this enzyme. Further studies will validate the role of GST pi estimation in predicting the potential malignancy of OED.

Adult↗
PubMed1997

Diagnosis of an advanced endodontic/periodontic lesion: report of a case.

Diagnosis of endodontic/periodontic lesions is often a challenge for clinicians. Treatment will not be successful without correct diagnosis. This article presents an advanced case of an endodontic/periodontic lesion in a patient who was referred to a periodontist. After careful examination of the patient, as well as consultation with an endodontist, an endodontic diagnosis was made and the patient treated accordingly. Success was attained without periodontal intervention.

Alveolar Bone Loss↗
PubMed1997

Diurnal variation of gamma-glutamyl transpeptidase activity during DMBA-induced hamster buccal pouch carcinogenesis.

OBJECTIVE: The aim of the present study is to assess the diurnal variation of gamma-glutamyl transpeptidase (GGT) during 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis. MATERIALS AND METHODS: The right buccal pouches of 108 Syrian golden hamsters, divided into three experimental groups, were treated three times weekly with 0.5% DMBA in mineral oil over an 11-week treatment regimen. The left buccal pouches were untreated and served as the controls. Within each group, six animals were killed at 4-h intervals (04.00, 08.00, 12.00, 16.00, 20.00 and 24.00) for 24 h. GGT histochemical stain, according to the method of Ruthenberg and coworkers, was applied. The number of GGT-positive foci in the pouch mucosa was recorded at 3, 7 and 11 experimental weeks. RESULT: Diurnal variation of GGT histochemical activity during DMBA-induced hamster buccal pouch carcinogenesis was substantiated in the present study. CONCLUSION: This investigation highlights the importance of the diurnal variation in experimental oral carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1997

Cancer-promoting effect of Taiwan betel quid in hamster buccal pouch carcinogenesis.

OBJECTIVE: To investigate the cancer-promoting effect of Taiwan betel quid in hamster buccal pouch carcinogenesis. MATERIALS AND METHODS: Two hundred and fifty-two non-inbred male adult Syrian golden hamsters were randomly divided into six groups, each containing forty-two animals. A treatment regimen over a 14-week experimental period was employed with six animals per group being killed at seven different periods (every 2 weeks). The right buccal pouch of each animal was painted three times a week with various combinations of 7,12-dimethylbenz[a]anthracene (DMBA), Taiwan betel quid extract, dimethyl sulfoxide (DMSO) and mineral oil. RESULT: Both the number and size of tumors in animals concurrently treated with DMBA and betel quid were significantly higher than those in animals treated with DMBA alone in each killing period of 8, 10, 12 and 14 weeks. No visible tumors but hyperkeratosis and acanthosis were observed in pouches treated with betel quid alone for all killing periods. CONCLUSION: Our results indicate Taiwan betel quid may be a co-carcinogen in human oral carcinogenesis, if extrapolation can be made from the current animal study.

Animals↗
PubMed1997

The effect of shovel trait on Carabelli's trait in Taiwan Chinese and Aboriginal populations.

Chinese and other Mongoloid populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to compare the association between the shovel and the Carabelli's traits between Chinese and aboriginal Mongoloid populations. The research is designed to sample randomly a Chinese population and an aboriginal population having low admixture with neighboring populations. The Mongoloid aboriginal group was from the Bunun tribe who resides in an isolated alpine area in Taiwan. The effects of sex and age on Carabelli's trait were controlled in this study, as was the association between tooth size and Carabelli's trait. Our results show that males had more Carabelli's trait expressed on teeth than females in both of these two Mongoloid populations. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After controlling for sex, age, and tooth size, the existence of the shovel trait significantly increased the likelihood of having Carabelli's trait, especially in Chinese, which implies another significant ethnic feature for Mongoloid identification.

Adolescent↗
PubMed1997

Attenuation of x-ray in muscle and alveolar bone during mandibular premolar periapical radiographic procedure.

The main purpose of this study is to find out the degree of attenuation when the x-ray entrances the skin and reaches the film at the bone area near the mandibular premolar root apex. In this study we used thermaluminescent dosimeters (TLDs) to measure the entrance dose and exit dose directly at the area of interest and calculated the penetration value P. We also simulated the attenuation process and calculated the P value in similar conditions. The results indicate that the mean P value of direct measurement from patient is 0.071 +/- 0.018 (60kVp, HVL = 1.5mm Al), while that for theoretical calculation is 0.06458 at 27keV. We concluded that P value of direct measurement can match with the theoretical value and further studies in jaw bone density and other related portions is worthwhile.

Alveolar Process↗
PubMed1996

Logistic analysis of the effects of shovel trait on Carabelli's trait in a Mongoloid population.

Mongoloid populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the effects of the shovel trait on Carabelli's trait in a Mongoloid population. The research design sought a population that resides in an isolated area and exhibits low admixture with neighboring populations. The Mongoloid group selected for study was the Bunun tribe of aborigines who inhabit an alpine area in Taiwan. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After adjusting for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of three, an effect that is significant.

Adolescent↗
PubMed1996

Fourier and non-Fourier pattern discrimination compared.

Various studies indicate the existence of non-Fourier visual mechanisms that can extract non-luminance cues (e.g., contrast modulation) as well as a Fourier mechanism that deals with luminance variation only. We compared the pattern discrimination performance of the non-Fourier mechanism with that of the Fourier mechanism by using orientation discrimination and spatial-frequency discrimination tasks. The Fourier patterns used were D6s, the sixth spatial derivative of a Gaussian function multiplied by another Gaussian function in the orthogonal dimension. The corresponding non-Fourier patterns were D6 contrast-modulated cosine gratings. Our results showed a similar trend for the non-Fourier and the Fourier performance at various peak spatial-frequencies or orientations of D6. However, the discrimination threshold of the non-Fourier mechanism was about two-fold higher than that of the Fourier mechanism. The oblique effect was also stronger for non-Fourier patterns. In addition, worse performance for non-Fourier patterns at short stimulus durations (around 33.3 msec) was consistent with the prediction of the two-stage non-Fourier model, which requires more time for the additional rectification and filtering operations.

Cues↗
PubMed1996

Epidermal growth factor in gingival crevicular fluid and its binding capacity in inflamed and non-inflamed human gingiva.

Epidermal growth factor (EGF) is a pro-inflammatory small peptide (6000 Da) with a variety of biological activities including stimulation of cell differentiation and mediation of proteolysis by binding to its specific receptor on the cell surface. The purpose of this study was to determine the levels of EGF in gingival crevicular fluid (GCF) and the EGF-binding capacity to its receptor in gingival tissue. The GCF samples were collected from six patients by inserting paper strips into shallow (< 5 mm) and deep pockets (> or = 5 mm) for 30 s. The strips were soaked in 0.2 M acetate for extraction and the EGF in the supernatants was analysed by radioimmunoassay. To determine the binding capacity of EGF to its receptor, inflamed gingival tissues (pocket depth > or = 5 mm, Gingival Index = 1, 2 or 3) were collected during periodontal flap surgery and non-inflamed gingival tissues (pocket depth < 5 mm, Gingival Index = 0) were collected during surgical "crown lengthening' for aesthetic purposes. The tissues were pooled by group, homogenized for membrane preparation and the supernatants obtained after centrifugation were used in a 125IEGF binding assay. To determine the effect of inflammation on gingival EGF receptor, inflamed and non-inflamed gingival tissues were collected from six patients and prepared similarly to the binding assay. Gingival preparations were then electrophoresed for Western blot analysis with EGF receptor antiserum. The EGF level in GCF was significantly lower (P < 0.05) in the samples collected from pockets > or = 5 mm (0.9 +/- 0.6 ng/ml) than in those from pockets < 5 mm (2.4 +/- 2.1 ng/ml). The average Gingival Index was higher (2.6 +/- 0.6) in pockets > or = 5 mm than in pockets < 5 mm (1.4 +/- 1.0). Specific binding of 125I-EGF to its receptor in inflamed gingiva was 2.7-fold higher than in non-inflamed gingiva (14.4 +/- 4.9 vs 5.4 +/- 1.8 fmol/g wet tissue). Western blot analysis showed two major immunoreactive bands (180 and 120 kDa), which represent EGF receptor and its degradation products, in inflamed gingiva. The findings show that inflammation activates EGF binding capacity in gingiva and that the up-regulation of EGF receptor in inflamed gingiva might be associated with a lowered concentration of EGF in GCF produced adjacent to inflamed gingiva. This up-regulation of EGF receptor during inflammation might be an important mechanism in the pathogenesis of periodontal disease.

Blotting, Western↗
PubMed1996

Detection of epidermal growth factor receptor in inflammatory periapical lesions.

Epithelial cell proliferation is often observed in periapical lesions of endodontic origin. The mechanisms which stimulate the epithelial cell rests of Malassez to proliferate are not understood fully. Fifteen inflammatory periapical lesions (10 granulomas and five cysts) obtained from periapical surgery and six additional periapical lesions (four granulomas and two cysts) collected from extracted teeth were examined using immunohistochemical staining and 125I-EGF (epidermal growth factor) binding assay to detect the presence of epidermal growth factor receptor. The results indicated that the periapical lesions without epithelial cell proliferation had a weak immunoperoxidase staining or low specific binding of 125I-EGF. In contrast, the periapical lesions with epithelial cell proliferation and cyst formation exhibited a strong immunoperoxidase staining in the epithelial cells or high specific binding of 125I-EGF.

Epidermal Growth Factor↗
PubMed1996

Periradicular curettage.

Periradicular curettage is a part of the treatment procedure of periradicular surgery. Its main purpose is to remove pathological periradicular tissues for visibility and accessibility to facilitate the treatment of the apical root canal system, or sometimes for the removal of harmful foreign materials present in the periradicular area. Inflammatory periradicular lesions (granuloma and cysts) are the responses of the periradicular tissues to irritants from the root canal and not from the periradicular area unless medicaments and/or filling materials have been forced through the apical foramina or perforations into the periodontium. Histologically, the inflammatory periradicular lesion is similar to healing granulation tissue, which is composed of cells which have natural and specific immunological defence capability and cooperate by means of cytokines to amplify the protective mechanisms of the host. Accordingly, it is not necessary to completely curette out all the inflamed periradicular tissues during surgery, since this granulation-like tissue will be incorporated into the new granulation tissue as part of the healing process. To control the source of irritants in the root canal is far more important than to remove all periradicular tissues affected by the irritants. The successful removal of all irritants from the root canal system results in resolution of pulpally induced periradicular lesions. In the case where the periradicular lesion is caused by endodontic instruments or cytotoxic filling materials placed in the periradicular tissues, removal of these foreign objects is required for resolution of the lesion.

Animals↗