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Biomedical subjects

T J Li

Publications and source records attributed to T J Li.

34 records · Page 2Linked to original sources
PubMed1998

Recurrence of unicystic ameloblastoma: a case report and review of the literature.

Unicystic ameloblastoma is believed to be less aggressive and responds more favorably to conservative surgery than the solid or multicystic ameloblastomas. We report a case of unicystic ameloblastoma that was initially treated by marsupialization and later by enucleation under suspicion of a dentigerous cyst. The neoplastic nature of the lesion became evident only when the enucleated material was available for histologic examination. Apart from an ameloblastomatous epithelial lining and luminal tumor nodules, the cystic tumor contained numerous tumor islands within its fibrous capsule. The lesion recurred 8 years after the enucleation. This case supports the view that the presence of tumor islands in the fibrous capsule may indicate a high risk of recurrence for unicystic ameloblastomas. Relevant diagnostic problems and choice of treatment are presented along with a review of the literature.

Ameloblastoma↗
PubMed1997

Glutathione S-transferase pi-class as a tumour marker in lingual preneoplastic and neoplastic lesions of rats and humans.

Immunocytochemical expression of the pi class glutathione S-transferase (GST) was investigated in preneoplastic and neoplastic lingual lesions in a 4-nitro-quinoline 1-oxide (4NQO)-induced rat genetic model [Wistar/Furth rats (WF) and Dark-Agouti rats (DA)] and in human surgical material [fibrous polyp, mild to moderate dysplasia, severe dysplasia, carcinoma in situ (CIS), squamous cell carcinoma (SCC)]. Two polyclonal antibodies raised against rat (GST-P) and human (GST-pi) antigens were used. In the rat model, DA and WF rats showed contrasting susceptibility to 4NQO, DA rats having a much higher tumour incidence and a significantly shorter survival time than WF rats. While the established lingual SCC in DA and WF rats all expressed GST-P, the number of GST-P+ foci in the preneoplastic lingual epithelium was significantly higher in DA (14.5 +/- 6.5) than in WF rats (5.5 +/- 2.6; P < 0.0001). In contrast, GST-pi epithelial staining in human specimens was more variable and the results overlapped in different groups. More frequent nuclear and/or basal cell staining was detected in severe dysplasia, CIS and SCC than in benign and mild to moderate dysplastic lesions. Although the pi class GST may be a useful marker for rat lingual carcinogenesis, its value in clinical applications is unclear. GST-pi staining patterns and their distribution may be helpful in identifying high-risk lingual lesions in humans.

4-Nitroquinoline-1-oxide↗
PubMed1997

Immunocytochemical expression of parathyroid hormone related protein (PTHrP) in odontogenic jaw cysts.

OBJECTIVE: To investigate the immunocytochemical expression of parathyroid-hormone-related protein (PTHrP) in odontogenic jaw cysts. DESIGN: Retrospective study of archival tissue. SETTING: University department, UK. MATERIAL: Odontogenic keratocysts (n=27), and dentigerous and radicular cysts (n=10 each). INTERVENTION: Immunocytochemistry by biotin streptavidin technique. MAIN OUTCOME MEASURE: Intensity of staining of PTHrP determined by TV image analysis. RESULTS: The epithelial linings of all the odontogenic keratocysts, 9/10 dentigerous, and 8/10 radicular cysts showed reactivity for PTHrP mainly localised to the basal and suprabasal layers. Odontogenic keratocyst linings expressed significantly higher levels of PTHrP than those of dentigerous and radicular cysts (P<0.003 in each case). There were no differences in epithelial expression of PTHrP between solitary, recurrent and naevoid basal cell carcinoma syndrome-associated odontogenic keratocysts. The fibrous tissue walls of all types of cyst reacted strongly for PTHrP with a trend towards decreasing intensity from odontogenic keratocysts, to dentigerous and then radicular cysts. CONCLUSION: It is possible that PTHrP modulates growth and bone resorption in odontogenic cysts. PTHrP may act synergistically with interleukin-1 to increase bone resorption or stimulate osteoblasts and inhibit osteoclasts (resulting in reduced resorption) via its transforming growth factor beta-like activity.

Analysis of Variance↗
PubMed1997

Intra-articular fibroma of tendon sheath in the temporomandibular joint.

Fibroma of tendon sheath is an uncommon soft tissue tumor. The first case involving the temporomandibular joint is reported here. The patient presented with chronic clicking, pain, and swelling of the right temporomandibular joint associated with restricted jaw opening. Histologic, immunocytochemical, and ultrastructural features of the intra-articular tumor were identical to fibroma of tendon sheath. The variability of symptoms and the diagnostic problems presented by this tumor are discussed.

Actins↗
PubMed1997

Myxoglobulosis in an extravasation mucocele of the lower lip.

A case of extravasation mucocele showing an unusual intraluminal globular organization of the mucous content is described. The cystic lesion was obtained from the lower lip of a 10-year-old Japanese girl and presented as a painless swelling of 1 year duration. Histologically, the cyst cavity was filled with round globules and encapsulated by a granulation tissue wall devoid of a lining epithelium. To our knowledge this peculiar histological pattern has not been previously described in an oral mucocele. Clinicopathological features of 'myxoglobulosis of the appendix', a morphological variant of appendiceal mucocele, appear to be related to the present case.

Child↗
PubMed1996

Kimura's disease: a clinicopathologic study of 54 Chinese patients.

Kimura's disease, a chronic inflammatory condition of unknown cause, is endemic in Orientals. The present study documented 54 cases of Kimura's disease in patients from mainland China. The main clinical features of this series included young and middle-aged male predominance (male:female = 3.5:1), predilection for the head and neck regions, and a long duration. The disease presented as either single (31 cases), or multiple lesions (23 cases), and mainly involved subcutaneous tissues (29 cases), major salivary glands (21 cases), and lymph nodes (17 cases) in isolation or in combination. Histopathologically, the lesion was characterized by hyperplasia of lymphoid tissue with well-developed lymphoid follicles, marked infiltration of eosinophils, proliferation of thin-walled capillary venules, and varying degrees of fibrosis. Distinctive features of salivary glands and nodal involvement were also described. Differences between Kimura's disease and angiolymphoid hyperplasia with eosinophilia, mostly reported in the West, were discussed to draw attention to their distinction.

Adolescent↗
PubMed1996

Genetic controls of susceptibility and resistance to 4-nitroquinoline 1-oxide-induced tongue carcinomas in rats.

We analyzed the incidence of infiltrative mass-type tongue carcinomas (IMTC) induced in 550 rats by continuous oral administration of 0.001% 4-nitroquinoline 1-oxide solution for 180 days. The study included various crosses of susceptible Dark-Agouti rats (DA) and resistant Wistar/Furth rats (WF). DA showed a 93.6% incidence of IMTC measuring more than 5 mm in their largest diameter, while WF showed only a 4% incidence. Reciprocal F1 and F2 hybrids mated by DA and WF showed 47.5% and 45.8% incidences, respectively. Meanwhile, reciprocal backcrossed hybrids to DA and WF showed 73.7%, and 24.6% incidences, respectively. Segregation of the incidences suggests that there are two autosomal dominant genes, one linked to the susceptibility of DA and the other to the resistance of WF.

4-Nitroquinoline-1-oxide↗
PubMed1996

p53 expression in odontogenic keratocyst epithelium.

The expression of p53 protein was studied in odontogenic keratocysts (OKC, 11 solitary, 5 recurrent and 6 NBCCS cysts), radicular (RC, n = 5) and dentigerous (DC, n = 5) cysts, using a panel of antibodies to p53 (clone BP53-12, clone 1801 and polyclonal CM1) and a sensitive biotin-streptavidin method on paraffin embedded sections. Of the three antibodies tested, clone BP53-12 gave the most intense and consistent nuclear staining pattern. Clone 1801 and polyclonal CM1 stained only 38% and 71% OKC linings, respectively, but not RC and DC linings. However, BP53-12+ cells were detected in the epithelial linings of all cyst types. Quantification of BP53-12+ cells was performed by manual counting and by relating cell number to unit length of basement membrane as determined by TV image analysis. BP53-12+ cell counts in solitary OKC linings (25.5 +/- 11.0 cells/mmBM) were significantly greater than those in DC (9.3 +/- 4.9 cells/mmBM, P < 0.01) and RC (6.7 +/- 2.6 cells/mmBM, P < 0.01) linings. The epithelial distribution of positive cells in OKC was predominantly suprabasal, which also varied from that of DC and RC linings (P < 0.005). There were no detectable differences in BP53-12 reactivity between the different subtypes of OKC (i.e., solitary, recurrent and NBCCS-associated OKC; P > 0.1). When data for the NBCCS-related OKC group were excluded, there was a significant correlation (r = 0.55, P < 0.01) between p53 and Ki67 labelling. To detect the presence of p53 gene mutations, genomic DNA, extracted from paraffin sections of OKC (4 solitary, 2 recurrent and 4 NBCCS cysts), RC (n = 3) and normal oral mucosa (n = 1), was subjected to a combination of polymerase chain reaction and single-stranded conformation polymorphism (PCR-SSCP) analysis for exons 5-10 of the p53 gene. Exon 4 was not analysed because of compromised DNA quality. No abnormality in banding patterns was found and all samples gave results similar to DNA from known, sequenced, normal p53 gene controls. Absence of p53 mutations within exons 5-9 was confirmed by the direct sequencing of 2 fresh frozen OKC samples (1 solitary and 1 NBCCS cyst). These results suggest that overexpression of p53 protein in OKC epithelium, detected by immunocytochemistry, is not reflected by alteration of the p53 gene and presumably reflects overproduction and/or stabilisation of normal p53 protein.

Antibodies↗
PubMed1995

Expression of proliferating cell nuclear antigen (PCNA) and Ki-67 in unicystic ameloblastoma.

The expression of proliferating cell nuclear antigen (PCNA) and Ki-67 was studied in unicystic and solid ameloblastoma (follicular and plexiform types) using a biotin-streptavidin method on routinely processed paraffin sections. To determine percentage PCNA and Ki-67 labelling indices, positive tumour cells and total tumour cells were counted in areas of each unicystic ameloblastoma corresponding to cystic linings, intraluminal nodules and invading tumour islands, and in solid ameloblastomas. Positive cells in basal and suprabasal layers of cystic tumour lining were also counted with respect to the length of basement membrane determined by image analysis. In unicystic ameloblastoma the invading islands exhibited a significantly higher PCNA labelling index (29.2 +/- 16.4%) than intraluminal nodules (13.6 +/- 5.4%; P < 0.05). Cystic tumour lining had relatively few PCNA positive cells and a labelling index (5.5 +/- 3.3%) significantly lower than invading islands (P < 0.001) or intraluminal nodules (P < 0.003). The labelling indices of solid ameloblastomas of follicular type (48.1 +/- 12.9%) were significantly higher than those of cystic tumour lining (P < 0.0001), intraluminal nodules (P < 0.001) and invading islands (P < 0.04) in unicystic ameloblastoma. Similar relationships were found for Ki-67 expression except that comparisons involving invading islands and intraluminal nodules were not significant, a finding probably due to the smaller number of specimens available for quantitative analysis. These results indicate differences in proliferative potential between different areas of unicystic ameloblastoma and between unicystic and solid lesions. The fact that invading tumour islands within the fibrous tissue wall showed high labelling indices is in agreement with the clinical observation that their presence may be related to recurrence after conservative surgery. This provides a biological basis for indicating more radical surgical excision as the treatment of choice for this subgroup of lesions.

Ameloblastoma↗
PubMed1995

Epithelial cell proliferation in odontogenic keratocysts: a comparative immunocytochemical study of Ki67 in simple, recurrent and basal cell naevus syndrome (BCNS)-associated lesions.

The aim of the present study was to investigate epithelial cell proliferation in the linings of odontogenic cysts, including three different subtypes of odontogenic keratocyst (OKC), namely simple (non-recurrent), recurrent and basal cell naevus syndrome (BCNS)-associated lesions. Ki67 immunoreactivity in OKC (simple, n = 10; recurrent, n = 8; syndrome, n = 9), dentigerous cysts (DC, n = 5), radicular cysts (RC, n = 5) and normal oral mucosa (n = 7) was studied using a biotin-streptavidin-peroxidase method on paraffin sections after microwave treatment. Ki67+ epithelial cells were counted manually and related to the length of basement membrane (BM) as determined by TV image analysis. Data were analysed by the Mann-Whitney U test. The number of Ki67+ cells in simple OKC linings (53.1 +/- 17.8 cells/mmBM) was similar to that in oral epithelium (42.5 +/- 12.7 cells/mmBM; P > 0.2). However, both contained significantly more Ki67+ cells than DC (3.9 +/- 1.3 cells/mmBM) and RC linings (6.7 +/- 4.8 cells/mmBM; P < 0.006). The epithelial distribution of Ki67+ cells differed between groups, with the percentage of positive cells in basal layers in OKC linings (7.0 +/- 2.1%) being significantly lower than that of oral epithelia (35.9 +/- 5.6%), DC (78.4 +/- 8.4%) and RC (80.6 +/- 7.7%) linings respectively (P < 0.003). Comparison of Ki67 expression within the OKC group revealed no significant difference between simple and recurrent lesions (44.0 +/- 13.8 cells/mmBM; P > 0.3). However, OKC associated with BCNS contained significantly higher numbers of Ki67+ cells (91.8 +/- 35.6 cells/mmBM; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Quantification of PCNA+ cells within odontogenic jaw cyst epithelium.

The aim of this study was to investigate the reactivity of the epithelial linings of the three major types of odontogenic cyst with a monoclonal antibody to proliferating cell nuclear antigen (PCNA; clone PC10). PCNA expression was studied in odontogenic cysts (n = 31) and normal oral epithelium (n = 10) using a biotin-streptavidin method on routinely processed paraffin sections. PCNA+ cells were counted manually and related to the length of basement membrane (mm) and the epithelial area (mm2) as determined by TV image analysis. The epithelial linings of odontogenic keratocysts (OKC; n = 11) contained the highest number of PCNA+ cells, most of which were located in the suprabasal layers. The mean value of PCNA+ cells in OKC linings (94.4 +/- 22.7 cells/mm) was similar to that of oral epithelia (80.8 +/- 20.6 cells/mm), but both were significantly higher than that of dentigerous (n = 10, 5.1 +/- 3.0 cells/mm) and radicular (n = 10, 11.0 +/- 4.1 cells/mm) cyst linings (P < 0.005). The epithelial distribution of PCNA+ cells differed between groups with the basal/suprabasal PCNA+ cell ratio in OKC linings (0.05 +/- 0.02) being significantly lower than that of normal oral epithelium (0.5 +/- 0.14), dentigerous (1.6 +/- 1.23) and radicular (1.9 +/- 1.09) cyst linings respectively (P < 0.005). These results demonstrate differences in PCNA expression between the epithelial linings of the major odontogenic cyst types, indicating differences in proliferative and differentiation processes within these lesions.

Antigens, Neoplasm↗
PubMed1994

[An preliminary study on hepato-protective action of seed oil of Hippophae rhamnoides L. (HR) and mechanism of the action].

The seed oil of Hippophae rhamnoides markedly inhibits the rise of MDA in liver of mice and rats induced by CCl4, AAP and ethyl alcohol, decreases significantly the activity of SGPT and SGOT, and markedly checks the depletion of GSH in liver of mice induced by AAP. The microscopic and electron-microscopic examination has shown that the seed oil can lighten liver injury.

Acetaminophen↗
PubMed1993

Expression of epidermal growth factor receptors by odontogenic jaw cysts.

The expression of epidermal growth factor receptor (EGFr) by odontogenic epithelium was studied in odontogenic cysts (n = 35), ameloblastoma (n = 6), and periapical granulomas containing proliferating epithelial rests of Malassez (n = 7) using a panel of monoclonal antibodies to EGFr (clone E30, F4 and C11) known to react with formalin-fixed, paraffin-embedded sections. Odontogenic epithelium in all specimens demonstrated immunoreactivity with all three antibodies. Clone E30 consistently gave the most intense, membrane located staining pattern of the three antibodies tested. Generally, staining of epithelial cells progressively diminished with movement away from the basal cell layers toward the most superficial layers of cystic lining or centre of epithelial rests and tumour islands. Developmental odontogenic cysts (odontogenic keratocysts, n = 13; dentigerous cysts, n = 11) and ameloblastoma (follicular type, n = 5; unicystic type, n = 1) expressed a higher level of EGFr staining than inflammatory cysts (radicular cysts, n = 11) and the proliferating epithelial rests in periapical granulomas. However, foci of weak EGFr staining of odontogenic keratocyst lining, similar to that seen in radicular cysts, were found in areas associated with inflammation. In addition, epithelial rests not associated with inflammatory cell infiltrates exhibited stronger reactivity for EGFr than proliferating rests within periapical granulomas. These results indicate that the level of EGFr expression by odontogenic cysts and rests is related to the presence of inflammation within adjacent connective tissue and that there is no detectable difference in receptor expression between developmental cysts and ameloblastoma.

ErbB Receptors↗