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At least 469 records · Page 26Linked to original sources
PubMed1983

Alteration in the reactivity of hamster cheek pouch arterioles to prostaglandin E2 and noradrenaline during pregnancy or sex steroid treatment.

Dioestrous and pregnant, or ovariectomized hamsters treated with sunflower oil, oestradiol or progesterone were anesthetized with pentobarbital and the arterioles of the cheek pouch membrane were prepared for microcirculatory study. Prostaglandin E2 (PGE2) or noradrenaline (NA) were topically applied and changes of the arteriolar diameter were measured on the screen of a closed-circuit television. PGE2 induced arteriolar dilatation in dioestrous or ovariectomized hamsters, but induced vasoconstriction in pregnant or in oestrogen-treated animals. Vasoconstriction induced by PGE2 in oestrogen-treated animals disappeared after administration of alpha-adrenergic blockers. In this situation, PGE2 induced vasodilatation once again. NA elicited arteriolar constriction in each experimental group. In ovariectomized hamsters treated with oestrogen the constriction was more pronounced than in progesterone treated animals. In pregnant animals it was significantly greater on day 14 than in dioestrous animals. Progesterone treatment blunted the vascular effect of both PGE2 and NA. It was concluded that the reverse effect of PGE2 and the increased sensitivity to NA induced by high oestradiol levels may have roles in the regulation of local blood flow during the ovarian cycle and pregnancy.

Animals↗
PubMed1984

Prostaglandin endoperoxides and thromboxane A2 in thrombus formation in the hamster cheek pouch in vivo.

Electrical stimulation in the presence of ADP of arterioles of the hamster cheek pouch caused endothelial damage and white thrombus formation. The thrombus formation was inhibited by cyclo-oxygenase inhibitors aspirin and sulphinpyrazone and its thioether derivative G 25671. Thromboxane synthetase inhibitors N-(7-carboxyheptyl) imidazole and butylimidazole failed to inhibit thrombus formation, although in the same doses both compounds inhibited serum levels of thromboxane. These results indicate that thromboxane is not important in thrombus formation in the hamster, but that prostaglandin endoperoxides are more significant. However, it is possible that the inhibition of white thrombus formation by aspirin, sulphinpyrazone and G 25671 may be mediated by a different mechanism altogether.

Animals↗
PubMed1978

Bradykinin and prostaglandin E1, E2 and F2alpha-induced macromolecular leakage in the hamster cheek pouch.

The hamster cheek pouch prepared for intravital observations on macromolecular permeability with fluorescein labelled dextran was used in four series of 5 hamsters each, all pretreated with indomethacin. Bradykinin, PGE1, PGE2 and PGF2alpha increased macromolecular leakage at postcapillary venules, and this leakage was reversible on removal of agent. A linear relation was found between the logarithmic value of dose of bradykinin and the mean number of leakage sites. No tachyphylaxis to bradykinin was seen. The effect of either PGE1, PGE2 or PGF2alpha applied simultaneously with bradykinin was to significantly (p less than 0.05) potentiate the bradykinin response. Bradykinin and these prostaglandins appeared to have the same site of action for their effect of increasing permeability, e.g. the postcapillary venule.

Animals↗
PubMed1984

The effects of catalase, indomethacin and FPL 55712 on vascular permeability in the hamster cheek pouch following scald injury.

The effects of scald injury and scald injury with pretreatment on plasma and water content were studied in the superfused hamster cheek pouch. Catalase (30,000 Units/kg), indomethacin (2.5 mg/kg) and FPL 55712 (2 mg/kg) were administered prior to 10 second scald with 100 degrees C normal saline. Plasma content was measured with 125 I serum albumin and water content was calculated by loss on drying. Significant (P less than 0.05) decreases in plasma content compared to scald alone were observed following pretreatment with catalase (29%) indomethacin (31%) or FPL 55712 (52%). Water content in scalded pouches was significantly reduced by catalase (29%) and FPL 55712 (42%). Pretreatment when combined also resulted in significant reduction of plasma content but not water content. Results suggest that free-radicals, prostaglandins and leukotrienes are involved in vascular response by scald injury.

Animals↗
PubMed1988

A cheek splitting approach to the posterior oral cavity: a case report.

A cheek splitting incision giving good access to lesions of the posterior region of the mouth is described. The incision is particularly useful when the CO2 laser is being used for the resection of malignant neoplasms. For cosmetic reasons the incision is most suitable in elderly patients.

Aged↗
PubMed1988

Use of a latissimus dorsi myocutaneous flap for closure of an orocutaneous fistula of the cheek.

The latissimus dorsi myocutaneous flap can be used successfully for external cover in the cheek region when the nature of the defect precludes the use of other local or regional flaps. It is exceedingly useful when a large amount of well-vascularized tissue is needed. The flap is extremely reliable and versatile as a one-stage reconstruction. Its major drawbacks are its bulkiness and the necessity to reposition the patient intraoperatively.

Back↗
PubMed1980

Influence of selenium on vascularization in the hamster cheek pouch.

The inhibitory effect of selenium (Na2SeO3) on the vascularization induced by amelanotic tumor implants (A Mel-4B32) n the Syrian hamster cheek pouch membrane is reported. Among control animals receiving A Mel-4B32 implants, 19 developed tumors out of 19 chambers with capillary proliferation being observed on day 4 after implant. Addition of 50 microgram Se to the chamber at the time of tumor implant delayed the initial observation of capillary proliferation until day 10 after implant. In the 50 microgram Se treated group, tumor-induced vascularization developed in 11 of 15 chamber implants and not in the remaining 4. Intermediate doses of 5 and 10 microgram Se added to the chamber at the time of tumor implant delayed the initial observation of capillary proliferation to days 7 and 9, respectively, with tumors developing in all chambers. Neither sodium nor sulfite altered the vascular pattern. Capillary proliferation was observed on day 4 after tumor implant when either 50 microgram NaCl or 50 microgram S as Na2SO3 were added to the chamber at the time of implant. Provision of Se as a drinking water supplement also delayed the onset of capillary proliferation.

Animals↗
PubMed1988

Enhanced expression of tonofilament bundles during hamster cheek pouch carcinogenesis is associated with tumour growth and the loss of high molecular weight keratins.

The altered pattern in the expression of keratin proteins as a function of tumour progression was studied in the hamster cheek pouch and compared the changes with electron microscopic observations using DMBA as a carcinogen. In the case of hyperplasia and well developed tumours a conspicuous loss of 67 K and an increase in 46 K was observed compared to the controls. The increased expression of low molecular weight keratins during tumour growth is well supported by the enhanced expression of tonofilament bundles, electron microscopically. This study suggests a triangular relationship between the presence of low molecular weight keratins-enhanced expression of tonofilament bundles and the undifferentiated nature of the oral tumours.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1983

Adherence of Streptococcus equi on tongue, cheek and nasal epithelial cells of ponies.

Streptococcus equi was found to adhere to tongue, cheek and nasal epithelial cells of ponies, in vitro. Maximum adherence was observed at pH 7.5 after one hour of incubation of bacteria with epithelial cells. This adherence was more on epithelial cells from adult animals than from foals. Streptococci exposed to heat (60 degrees C for 10 min) or treated with pepsin or trypsin showed a reduced adherence, whereas an increase occurred on treatment with hyaluronidase. Antibodies against whole S. equi cells or M-like protein blocked the adherence, whereas antibodies against group-specific carbohydrate or lipoteichoic acids did not. Pretreatment of epithelial cells with either the M-like protein or crude extract of S. equi lowered the adherence, whereas an extract of S. zooepidemicus did not. Adherence of S. equi to the epithelial cells was considered to be mediated by structures specific to S. equi.

Adhesiveness↗
PubMed1986

Indirect cervical lymphoscintigraphy in healthy subjects via submucosal cheek injections.

A new method of cervical lymphoscintigraphy is presented. It was performed on 16 healthy individuals via bilateral submucosal cheek injections with 99mTc-rhenium-sulfide-colloid. The ipsilateral uptake by the lymphatics on each side of the neck was consistently demonstrated in 15 subjects and allowed a comparative evaluation of the cervical lymphatic chains, including the submental, submandibular, jugulo-digastric and jugulo-omohyoid. The transverse cervical chain was demonstrated in 10 of 16 subjects. The method is simple, reliable and capable of clearly visualizing the lymphatic drainage of the oral cavity.

Adult↗
PubMed1996

The relationship between vascularity and cell proliferation in human normal and pathological lesions of the oral cheek epithelium.

The present study investigates relationships between neovascularisation and PCNA cell proliferation markers in different pathological lesions of the oral cheek mucosa. All specimens were fixed in 10% formalin and routinely processed for histology. Six normal (N) samples were taken from resection margins of benign lesions. The pathological lesions consisted of chronic inflammation (n = 10), lichen planus (n = 7), fibrous hyperplasia (n = 11), dysplasia (n = 5), squamous cell carcinoma (n = 22) and epithelium adjacent to carcinoma (n = 6). Adjacent 5 microns sections were stained with monoclonal antibodies against vimentin (clone no. V9) for identification of stromal blood vessels and against proliferating nuclear antigen (PCNA/PC10) using ABC immunoperoxidase techniques. Point counting was used to obtain the primary morphometric data using a Zeiss VIDAS image analyser. No attempt was made to classify the different types of blood vessels. The morphometric blood vessel parameters estimated were volume density, number per unit area, length per unit volume and mean transverse sectional area. PCNA indices were determined by estimating the percentage frequency of PCNA positive nuclei in basal and spinous strata. Generally, there were significant increases in all PCNA indices and blood vessel parameters between the N group and the different pathological lesions. A highly positive correlation was detected between all PCNA indices and blood vessel parameters. These data suggest that increased vascularity and angiogenesis occur in support of actively proliferating and transforming oral epithelial cells in order to permit growth. PCNA indices and blood vessel parameters may have a potential application as diagnostic and prognostic indicators.

Adolescent↗
PubMed2006

The blood vessel system in the periodontal ligament of the equine cheek teeth--part II: The micro-architecture and its functional implications in a constantly remodelling system.

The micro-vasculature of the equine periodontal ligament (PDL) was investigated using corrosion casts for scanning electron microscopy. Specimens from eight healthy warm-blooded horses were examined. Specific vascular features such as large ampullae with a diameter of up to 300 microm and blind vascular casts were found in the specimens of the equine PDL. The ampullae-shaped venules occurred only in the peripheral layer, where they were formed at the confluence of several vessels. Two types of blind stumps were identified. The first was developed in all three layers, while the second was found only in the peripheral layer. Blood-flow-regulating structures were not present in the equine PDL. As vascular valves are absent, the blood can flow in all directions. This polydirectional shift exists in all vascular layers. The vascular ampullae, present exclusively in the peripheral layer, are discussed here as specific features of a mechanism that can receive masticatory forces. Apart from its mechanical role, the vasculature must constantly adapt to the spatial changes resulting from the life-long eruption of the equine cheek tooth. This is facilitated by vascular sprouting and intussusceptive vascular remodelling. The blind ending stumps of the corrosion casts are typical equivalents of vascular sprouting. The large ampullae are interpreted as the first step in an intussusceptive process.

Animals↗
PubMed2006

The blood vessel system in the periodontal ligament of the equine cheek teeth--part I: The spatial arrangement in layers.

Corrosion casts of blood vessels in the periodontium of cheek teeth from eight horses were observed three-dimensionally with a dissection microscope. Selected specimens were examined in a scanning electron microscope. Periodontal blood vessels communicated with those from the gingiva, the alveolar bone, and the apical region. In the upper jaw, there were anastomoses with the blood vessels of the mucosa of the maxillary sinus. The periodontal vascular system was organized in two or three layers. The peripheral layer was mainly composed of large venules, the inner one consisted of capillaries. In the intermediate layer, blood vessels were post-capillary venules. This layer was developed only in horses under 10 years of age. In all layers the vascular orientation was mainly occluso-apical, this was defined as the standard pattern. There were many variations displayed in different courses of certain blood vessels. The vascular organization is discussed with regard to the specialized functions of the periodontal ligament (PDL). The wide vessels of the outer layer are thought to play a mechanical role as part of a shock absorbing system. The capillaries of the inner layer meet nutritional requirements. The disappearance of the intermediate layer in horses older than 10 years is taken as an adaptation to the remodelling of the PDL. Modifications in the standard pattern of vascular arrangements are also interpreted as adaptations to life-long changes in the periodontal space. Anastomoses between the periodontal vasculature and the blood vessels of the maxillary sinus indicate that periodontal disease may be transferred into the sinus.

Animals↗
PubMed2004

Biodistribution of GB-10 (Na(2)(10)B10H10 compound for boron neutron capture therapy (BNCT) in an experimental model of oral cancer in the hamster cheek pouch.

OBJECTIVE: We previously proposed the hamster cheek pouch model of oral cancer for BNCT studies. We herein present the biodistribution of a non-toxic boron compound, GB-10 (Na(2)(10)B10H10), in this model to assess its potential for BNCT or BNCT enhanced Fast Neutron Therapy. MATERIALS AND METHODS: We evaluated the uptake and retention of GB-10 in tumour and precancerous tissue and in potentially dose-limiting, clinically relevant normal tissues. RESULTS: Mean tumour boron concentration delivered by GB-10 (50mgB/kg) peaked to 77.7+/-28.0 ppm at 20min post-administration and remained at therapeutically useful values of 31.9+/-21.4 ppm at 3h. The clearance rate for normal tissues was faster than for tumour tissue. The consistently low brain and spinal cord values would preclude normal tissue toxicity. The uptake of GB-10 by precancerous tissue may be of potential use in the treatment of field cancerized areas. GB-10 was deposited homogeneously in different tumour areas, an asset when treating heterogenous tumours. The data suggests that the joint administration of BPA and GB-10 may improve the therapeutic efficacy of BNCT. CONCLUSIONS: GB-10 is a potential boron carrier for BNCT of head and neck tumours and for BNCT-FNT.

Animals↗