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At least 505 records · Page 28Linked to original sources
PubMed1981

Double-folded free myocutaneous flap to cover a total cheek defect.

This is a report of the successful reconstruction in two cases of a total cheek defect after radical maxillectomy with orbital exenteration for cancer of the maxillary sinus, in one stage, utilizing a double-folded free latissimus dorsi myocutaneous flap. The importance of preoperative angiography to identify suitable donor vessels, and of microneurovascular anastomosis to maintain the normal function of the transplanted muscle is stressed.

Angiography↗
PubMed1985

Reconstruction of the total cheek defect by free myocutaneous flap.

Our reconstructive method utilizing the free latissimus dorsi myocutaneous flap by microneurovascular anastomosis is a rewarding method for the patient with total cheek defect after cancer surgery of the maxillary sinus from the standpoint of morphology, function, and psychology.

Aged↗
PubMed1987

Effect of 2 episodes of cryosurgery on carcinogen-treated hamster cheek pouch.

Hamster cheek pouches were treated with the topical carcinogen DMBA for 8 weeks. 2 episodes of cryosurgery, located within the area of previous carcinogen application enhanced the neoplastic process by comparison with matched controls. Comparison with previous studies suggests that the 2 episodes of cryosurgery may have a greater effect in provoking overt malignancy than a single episode of cryosurgery.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1999

Benign mesenchymoma of the cheek: report of a case and review of the literature.

Benign mesenchymoma is a soft tissue neoplasm that contains 2 or more differentiated mesenchymal components in addition to fibrous tissue. A rare case of benign mesenchymoma of the cheek in a 6-year-old boy is presented. The literature pertaining to mesenchymoma in the head and neck region is reviewed and discussed.

Cheek↗
PubMed1980

An examination of the skin phase of schistosome migration using a hamster cheek pouch preparation.

A living hamster cheek pouch preparation has been used to study the skin phase of schistosomulum migration. Between 0 and 16 h post-exposure schistosomula become increasingly difficult to see and lateral movement in the skin ceases. Up to 50 h post-exposure they remain poorly visible. They lie in fluid-filled lacunae within the epidermis, external to the basement membrane. The first schistosomula enter the dermis from 40 h post-exposure, approximately half having done so by 52.5 h. Coincidentally, they can be more easily distinguished from surrounding tissue. Up to 91% of original penetrants have been observed alive in pouch tissue at 65 h post-exposure. Since only 26% eventually mature in the hepatic portal system there would appear to be considerable attrition subsequent to the skin phase of migration. The mean diameter of venules penetrated was 22.7 micrometers and the mean time taken to penetrate was 8.01 h. The majority of schistosomula left the pouch between 60 and 80 h post-exposure.

Animals↗
PubMed1985

Schistosoma mansoni: an ultrastructural examination of skin migration in the hamster cheek pouch.

The hamster cheek pouch has been used to investigate the skin migration of schistosomula at the ultrastructural level. Parasites have been observed up to 72 h post-infection. Despite rapidly reaching the epidermal basement membrane schistosomula remain in an epidermal location for at least 40 h post-infection, by which time the acetabular glands and their ducts have been lost and the transformation from cercaria to schistosomulum completed. Entry into the dermis and exit from the skin via the blood vessels is therefore by mechanical means or by lytic secretions emanating from a source other than the acetabular glands. The head gland which persists in the dermal schistosomula is a probable source of such secretions. The observations suggest that the apical area and musculature of the head capsule are important in gaining access to the lumen of blood vessels.

Animals↗
PubMed2004

The influence of oxidative stress on permeability of capillary vessels in the cheek pouch of hamsters with alloxan-induced diabetes.

BACKGROUND: The aim of the study was to assess the influence of oxidative stress on the increase of permeability of capillary vessels in animals with alloxan-induced diabetes. MATERIAL AND METHODS: The studies were performed in microcirculation system of hamster cheek pouch. After the blockade of histamine receptors and administration of diamine oxidase (DAO) and histamine into circulation fluorescein angiography was done. In addition, the influence of superoxide dismutase, aminoguanidine (DAO inhibitor) and trascolan (protease inhibitor) on vascular permeability caused by superoxide radical generation in DAO/histamine system was assessed. RESULTS: The number of extravasal leakages in the group receiving HA and DAO was significantly higher (p < 0.001) than in the groups receiving potential vascular "sealers", e.g. SOD, aminoguanidine or trascolan. In the group receiving aminoguanidine the number of leakages was significantly lower (p < 0.05) compared to the group receiving SOD or trascolan. CONCLUSIONS: The protective effect of aminoguanidine, superoxide dismutase or trascolan decreasing the vascular permeability, suggests that the increased vascular permeability is a result of superoxide radical generation by diamine oxidase.

Amine Oxidase (Copper-Containing)↗
PubMed2002

Solitary fibrous tumour of the mouth: report of two cases involving the tongue and cheek.

We describe two additional cases of solitary fibrous tumour (SFT) affecting the mouth. SFT is very uncommon in the oral cavity and we found only 14 cases reported in the literature. Our two cases were well circumscribed, slow growing tumours that, after surgical removal, did not recur. Case 1 was a 3 cm nodule on the right cheek. Hypo and hypercellular adjacent areas were mainly patternless, and the stroma was formed by thin collagen fibrils. Case 2 was a 4.8 cm mass in the anterior portion of the tongue. Microscopically it was formed by spindle cells embedded in a vascularized sclerotic collagen matrix. Some areas were hypercellular with scarce collagen fibrils. The immunohistochemical findings were similar in both cases, with strong immunoreactivity for vimentin, CD34, bcl-2, focal positivity for Ki-67 and negativity for other immunomarkers. Based on these clinical, microscopical and immunohistochemical features the final diagnosis of these two cases was SFT. Diagnosis of SFT is difficult and, although uncommon, it should be considered in the differential diagnosis of oral soft tissue tumours.

Adult↗
PubMed2003

Mitochondrial volume densities in the smokeless tobacco-treated hamster cheek pouch epithelium.

OBJECTIVES: To compare the morphological changes and quantitative distribution of mitochondria in the hamster cheek pouch (HCP) epithelium treated with smokeless tobacco (ST). MATERIALS AND METHODS: Archives of experimental material from previously published studies (Ashrafi et al., 1992) were utilized. Animals in experimental group received moist ST (snuff) in their right pouch, 5 days weekly for 24 months, while no snuff was given to control group. After 24 months, the epithelial tissues were processed for electron microscopy study. Volume densities of mitochondria were assessed by morphometry. MAIN OUTCOME MEASURES: Mitochondrial volume densities in the two groups, experimental vs control. RESULTS: In both control and experimental groups mitochondria were concentrated between the nucleus and basal cell plasma membrane. A decrease in the mean mitochondrial volume density (Vvmit) was observed from the basal layer to the more superficial layers in both groups. The experimental HCP displayed more mitochondria than control, and the granular epithelial cell layer in experimental group showed significantly a higher mean Vvmit than the control group (P = 0.03). It was concluded that greater numbers of mitochondria were retained in ST-treated granular cells of the hyperplastic epithelia than in the normal epithelium.

Animals↗
PubMed1972

Observations on the effect of thymectomy on chemical carcinogenesis in the hamster cheek pouch.

The effects of thymectomy and sham operation on 9,10-dimethyl-1,2-benzanthracene (DMBA) induced tumours of the hamster cheek pouch were studied in Syrian golden hamsters. The incidence of carcinomata and papillomata with intra-epithelial carcinoma (atypical papillomata) in these animals was compared with that in control animals treated with DMBA alone, without surgical intervention.In 32 non-operated control animals, the average tumour yield after 12 weeks' DMBA application was 2·13 carcinomata and 1·22 atypical papillomata per treated pouch. In 14 animals thymectomized at the age of 2 weeks, the tumour yield was 0·21 and 0·36, respectively, and in 10 animals thymectomized when adult, it was 0 and 0·1 respectively. In 9 animals sham operated on at the age of 2 weeks, an average of 1·56 carcinomata and 1·22 atypical papillomata were found, but in 13 animals which were sham operated when adult, the tumour yield was 0·54 and 0·15 per treated pouch, respectively.The results suggest that the time of thymectomy in relation to DMBA treatment may be of importance and that thymectomy, when performed in 2-week old hamsters, inhibits DMBA tumourigenesis. The major effect of thymectomy performed in adult hamsters appears to be related to stress following surgery.

Age Factors↗
PubMed1974

Transplantation of mouse plasmacytoma to the hamster's cheek pouch. I. Changes in tumour size and paraprotein concentration in the serum of the host.

Mouse myeloma cells (MPC-11) secreting gamma-2-b globulin were shown to proliferate into solid tumours after transplantation into the hamster cheek pouch. The implanted tumours continued to grow during the first 2 weeks; thereafter they diminished in size and disappeared completely a month after transplantation. The specific MPC-11 gammaglobulin could be detected in the serum of the hosts within 2 days after the transplantation and the changes in its concentration roughly correlated with the tumour size. The estimated half-life of the MPC-11 gammaglobulin in the circulation of the tumour-bearing hamsters was 4-6 days. Host resistance was demonstrated in tumour-bearing hamsters by their failure to develop tumours on second challenge with MPC-11 cells.

Animals↗
PubMed1981

Quantitative studies of hemidesmosomes during progressive DMBA carcinogenesis in hamster cheek-pouch mucosa.

The present study was designed to establish whether there are changes in hemidesmosomal distribution during defined stages of chemical carcinogenesis in hamster cheek-pouch epithelium. 0.5% DMBA in liquid paraffin was applied thrice weekly to hamster pouches and tissue samples were obtained at regular intervals and assigned to hyperplastic, dysplastic and carcinomatous groups on the basis of histological criteria. Untreated pouches served as controls. Following a strict sampling regime, electron micrographs were obtained from the epithelial-connective tissue junction and, using stereological intersection counting, the relative surface area of basal plasma membrane (BPM) occupied by hemidesmosomes was estimated. In normal epithelium 40% of the BPM is occupied by hemidesmosomes. During carcinogenesis, values decrease progressively and significantly to 35% in hyperplasia, 28% in dysplasia and 13% in carcinoma. A decrease in the relative area of hemidesmosomes would therefore appear to contribute to the increased motility of epithelial cells during a connective-tissue invasion and cellular metastasis.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Characterization of native fluorescence from DMBA-treated hamster cheek pouch buccal mucosa for measuring tissue transformation.

The steady-state native fluorescence spectra of extracts of normal mucosa as well as of different stages of oral lesion of the 7,12-dimethylbenz (a) anthracene (DMBA)-induced hamster cheek pouch carcinogenesis model have been measured and analysed at 405 nm excitation. The emission spectra were scanned from 430 to 700 nm to characterize the native fluorescence of endogenous porphyrin and other fluorophores under various tissue transformation conditions, such as hyperplasia, papilloma, early invasive carcinoma and well-differentiated squamous cell carcinoma. Two ratio parameters, R1 = (I530/I620) and R2 = (I530/I630), are introduced to quantify the diagnostic potentiality. The ratio values were found to decrease as the stage of the cancer increases. The suggested critical values for both R1 and R2 for normal mucosa is above three, and the suggested critical value for tissues with lesion is less than three. It was also found that the values for R1 and R2 for well-differentiated squamous cell carcinoma is less than one. The ratio parameter R2 is selected for discrimination between normal mucosa and oral lesions, as the difference in the R2 value between normal and DMBA-treated tissue is higher than that for R1.

9,10-Dimethyl-1,2-benzanthracene↗