Vascular volume and perfusion in hamster cheek pouch carcinomas and tumor-bearing cheek pouches.
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9,10-Dimethyl-1,2-benzanthracene↗
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Morphological study of bovine lung grafted into the hamster cheek pouch.
The hamster cheek pouch has been used extensively to study the modulation of microvascular responsiveness of native and transplanted tissues, because it is immunologically privileged. The purpose of this study was to determine the structural changes that occur over time in bovine lung tissue (donor) that was grafted into the hamster cheek pouch (recipient). Lungs from adult cows were cut into 1-mm-thick slices and grafted into the cheek pouch of adult Syrian golden hamsters (n = 60). After induction of anesthesia, bovine lung tissue was placed under the avascular tissue covering the cheek pouch, and the overlying skin was sutured. Intravital microscopy (IM) and transmission electron microscopy (TEM) of the cheek pouch and grafted tissue were performed 1, 7, 14, and 28 days after grafting. By using IM, we found blood flow throughout the grafted bovine lung tissue between days 7 and 14 post-transplantation. Both IM and TEM showed that the grafted tissue contained patent microvessels anastomosing with cheek pouch microvessels, alveolar structures, and interstitial tissue. Mast cell infiltration around microvessels of the grafted tissue was evident in all animals between days 14 and 28 post-grafting. No other inflammatory cells were identified throughout the observation period. By day 28 post-grafting, the entire lung tissue became fibrotic. We conclude that bovine lung tissue can be successfully transplanted into the hamster cheek pouch, that blood flow is established throughout the graft, and that prominent mast cell infiltration is associated with fibrosis of the graft 28 days after transplantation. We suggest that this model can be useful in studying pulmonary microvascular responses in situ.
Animals↗
Anterior "cheek" electrodes are comparable to sphenoidal electrodes for the identification of ictal activity.
Sphenoidal electrodes are used to localize epileptiform activity originating in the temporal lobe during complex partial seizures. Sphenoidal electrodes, however, are semi-invasive and uncomfortable to the patient. We compared skin electrodes placed on the cheek ("cheek electrodes") with sphenoidal electrodes for the detection of the side and site of complex partial seizure onset. In a masked, randomized comparison of single ictal recordings in 22 patients, there were no significant differences between sphenoidal and cheek electrode montages in detecting the side or site of ictal onset (P < 0.01). Signal/noise ratios for interictal spikes were a mean 16.5% greater at sphenoidal sites compared to cheek sites (paired t test, t = 2.4, P < 0.05). This difference, however, did not influence the detection of rhythmical ictal activity in cheek and sphenoidal montages in our study, nor the assignment of side, site or time of seizure onset by unbiased readers. Recordings from cheek electrodes are comparable to those from sphenoidal electrodes and are useful for localizing ictal activity.
Cheek↗
Keratinized epithelial transport of beta-blocking agents. I. Relationship between physicochemical properties of drugs and the flux across rat skin and hamster cheek pouch.
The maximum fluxes (Jmax) of beta-blockers through keratinized membranes were determined in vitro and compared with their physiochemical parameters such as lipophilicity (log k'0) and melting point (mp). Rat abdominal skin and hamster cheek pouch mucosa were used as the model membranes. Propranolol, metoprolol, timolol, pindolol, nadolol and agenolol were used as beta-blockers with a variety of physicochemical characters. Linear relations of Jmax with either log k'0 or mp were observed both in intact rat skin and in intact hamster cheek pouch, suggesting that the lipophilicity and thermodynamic activity of a drug in the crystal state primarily affect the drug's permeation through these membranes. However, the slope, dJmax/d(log k'0), for cheek pouch mucosa was greater than that for rat skin, corresponding to the lack of appendigeal shunt pathways in cheek pouch. Penetration studies using the delipidized membranes and the isolated stratum corneum sheet of hamster cheek pouch mucosa clarified that the primary rate-limiting barrier function might exist in the lipid layer of the stratum corneum. Jmax values for the tape-stripped and delipidized skins correlated with both the solubilities of drugs in the vehicle and with the mp, suggesting the polar porous characteristics of both model membranes. However, a theoretical approach confirmed that the contribution of an intracellular or aqueous pore route in the intact membrane to the permeation of drugs with positive lipophilic indexes is negligible.
Adrenergic beta-Antagonists↗
Closure of large nose-cheek groove defects.
Reconstruction of large defects involving the nose-cheek groove area present technical and cosmetic problems. A combination of a cheek falp with a dorsal-nasal rotation flap gives excellent survival and cosmesis for the nose as well as the cheek. The techniques of the dorsal-nasal flap alone and in combination with a cheek advancement flap are demonstrated.
Aged↗
Role of nitric oxide in modulating permeability of hamster cheek pouch in response to adenosine 5'-diphosphate and bradykinin.
The goal of this study was to determine the role of the synthesis and release of nitric oxide in modulating alterations in microvascular permeability of the hamster cheek pouch in response to adenosine 5'-diphosphate and bradykinin. We used intra-vital fluorescent microscopy to examine the permeability of the hamster cheek pouch to agonists before and following application of enzymatic inhibitors of nitric oxide, NG-monomethyl-L-arginine (L-NMMA; 0.01, 0.1, and 1.0 microM) and NW-nitro-L-arginine methyl ester (L-NAME; 0.01, 0.1, and 1.0 microM). Increases in permeability of the hamster cheek pouch were quantitated by the formation of microvascular leaky sites. ADP and bradykinin produced an increase in the number of venular leaky sites, and superfusion of L-NMMA and L-NAME significantly decreased ADP- and bradykinin-induced increases in microvascular permeability. To determine the specificity of nitric oxide blockade on microvascular permeability, we examined changes in permeability in response to adenosine, and examined the effects of D-NMMA on microvascular permeability. Adenosine-induced increases in permeability were not altered by treatment with L-NMMA, and D-NMMA did not inhibit ADP-induced increases in microvascular permeability. Thus, these findings suggest that production of nitric oxide, in response to application of ADP and bradykinin, has a role in modulating macromolecular permeability of the hamster cheek pouch in vivo.
Adenosine Diphosphate↗
Release of mandibular ankylosis due to gross tissue loss in the cheek.
Experience with mandibular ankylosis due to the loss of variable amounts of cheek tissue as a result of cancrum oris is reviewed. Where enough cheek has been lost to cause an ankylosis, replacement tissue in the form of a graft is necessary to prevent recurrence and to reconstruct the cheek. A number of methods are reviewed, including free grafts, local flaps and pedicled skin from the neck and abdomen. The best functional and cosmetic result was obtained by using a tubed pedicle of abdominal skin based on the superior epigastric artery and attached to the wrist as a carrier. This can be raised under local anaesthesia prior to the release of the ankylosis so it is available to cover the raw surfaces and to reform the cheek at the time of operation. Blind intubation was found to be feasible and desirable when compared with administering the anaesthetic through a trachesotomy. The importance of close supervision of post-operative exercises is emphasized, but was not able to be carried out under the conditions of treatment.
Ankylosis↗
The hamster cheek pouch as a convenient ectopic site for studies of uterine morphogenesis and endocrine responsiveness.
The Syrian hamster cheek pouch was evaluated as a convenient transplantation site for studies of estrogen-dependent uterine growth and morphogenesis. At one month of age, hosts were either ovariectomized (Ovex) or ovariectomized and estrogen implanted (Ovex+E2), and at the same time the uterus from a 7-day old untreated donor was transplanted into the host's right cheek pouch. Periodic inspection (by simple eversion of the pouch) revealed viable transplants in the majority of hosts for both groups, and clear evidence of estrogen-dependent transplant growth that continued for at least 9 months. At that time, weight of the transplanted uterus was comparable to that of a given host's own in situ uterus, but uteri at both sites weighed six to eightfold more in Ovex+E2 hosts than in Ovex hosts. Histological analysis also revealed similar degrees of endometrial atrophy in Ovex hosts and hypertrophy/hyperplasia in Ovex+E2 hosts for both in situ and transplanted uteri. Furthermore, while only scant and rudimentary endometrial glands developed in both in situ and transplanted uteri within Ovex hosts, uteri at both sites within the Ovex+E2 hosts were riddled with cystic glandular structures and exhibited marked leukocytic infiltration. These data demonstrate that neonatal uteri transplanted to the hamster cheek pouch will grow, differentiate and follow an endocrine-responsive morphogenetic program that is quantitatively and qualitatively consistent with that of the host's in situ uterus. Lastly, we were able to cleanly separate epithelium from the stroma of 5-day old hamster uteri, reassociate the two tissues in vitro, transplant the recombinants into cheek pouches of adult female hamsters and subsequently observe growth and maintenance of a generally normal uterine morphology and differentiated function.
Animals↗
Gore-Tex implant as tissue filler in cheek-lip groove rejuvenation.
The cheek-lip grooves, often referred to as nasolabial folds, are one of the facial characteristics most commonly complained about by patients in all age groups. A variety of methods for correction have been proposed, using implants or autografts. Some of the methods have relied on diminishing the crest lateral to the groove thus camouflaging the depth of the cheek-lip fold. These procedures have proven to be of limited effect, either because of the amount of correction obtained or because they are short-lasting. The Gore-Tex implant proved its safety and biocompatibility over the past decade as a vascular graft. The characteristics of this implant material are described and compared to other commonly used synthetic implants. A surgical technique of applying the Gore-Tex soft tissue patch in facial aesthetic surgery, particularly in cheek-lip rejuvenation, is presented. This technique has been applied in 17 consecutive patients for the correction of prominent cheek-lip grooves with a follow-up period of eight months. Results showed satisfactory improvement without significant complications.
Cheek↗
Comparison of the effects of four hyperplastic agents on hamster cheek pouch mucosa.
Hyperplasia in the hamster cheek pouch was examined using 4 different hyperplastic agents: oil of turpentine 50% v/v in liquid paraffin; vitamin A palmitate 10% w/v in liquid paraffin; 12-O-tetradeconyl-phorbol-13-acetate 16nM in acetone; and ethylphenylpropiolate 0.04mM in acetone. Acetone, paraffin and untreated control groups were also examined. Cheek pouches were painted 3 times a week for up to 4 weeks with each solution. Samples were removed and prepared for light microscopy 24 hours after 2 weeks of painting and 24 hours, 6, 12 and 18 weeks after 4 weeks of painting. Hyperplasia was produced by application of turpentine, vitamin A and TPA after 2 weeks of application. Further increases in epithelial width occurred after 4 weeks of painting in the turpentine and vitamin A groups but a decrease was seen in the TPA group. Six weeks (vitamin A and TPA groups) or 12 weeks (turpentine group) after the completion of treatment the epithelium had a normal histological appearance. No differences between the control or EPP treated cheek pouch mucosa could be detected. Turpentine and vitamin A can be used as models of reversible hyperplasia in the hamster cheek pouch.
Alkynes↗
[Effect of natural panting frequency and cheek support on the plethysmographic determination of thoracic gas volume in patients with chronic obstructive pulmonary disease].
The authors studied the effects of natural panting frequency (NF) and the cheek support on the plethysmographic measurement of thoracic gas volume (TGV) in 8 normal subjects (non-smokers) and 46 patients with chronic obstructive pulmonary disease (COPD). The patients were divided into 2 groups according to the degree of airway obstruction (group I; specific airway conductance (SGaw) greater than 0.1 (n = 18), group II; SGaw less than 0.1 (n = 28)). TGV was measured with a pressure-type body plethysmograph (BP). NF was 2.00 +/- 0.43 Hz (mean +/- SD) in control subjects, 1.92 +/- 0.78 Hz in group I, and 1.39 +/- 0.59 Hz in group II, respectively, indicating lower NF in the patients with severe airway obstruction. In control subjects and group I, the differences between TGV at NF and at 0.5-1.0 Hz (TGVNF-TGV1.0) were -0.01 +/- 0.07L, and -0.06 +/- 0.16L, respectively, and cheek support did not alter the difference. On the other hand, in group II, the difference was slightly larger than other groups in spite of the lower NF, and this overestimation was abolished by cheek support (0.13 +/- 0.25L-----0.06 +/- 0.27L, p less than 0.05). These results suggest that, in patients with severe airway obstruction, TGVNF may be overestimated even if NF is relatively low. This overestimation may be mainly due to the extrathoracic airway compliance including the cheek.
Adult↗
Modulatory effects of snuff, retinoic acid, and beta-carotene on DMBA-induced hamster cheek pouch carcinogenesis in relation to keratin expression.
The hamster cheek pouch (HCP) serves as an excellent model system not only for the studies on initiation and promotion but also for the modulation of experimental oral carcinogenesis. In our studies, HCPs treated with 7,12-dimethylbenz[a]anthracene (DMBA) showed both cheek pouch and stomach papillomas. Utilizing this model system, we tested and compared the modulatory effects of snuff, retinoic acid, and beta-carotene on the incidence of tumors and the keratin expression pattern. HCPs treated with snuff, either alone or in combination with DMBA, resulted in stomach papillomas. HCPs treated with snuff showed no cheek pouch tumors, and those treated with snuff and DMBA showed only 10-15% tumor incidence. Both beta-carotene and retinoic acid showed a total inhibition of DMBA-induced carcinogenesis in the HCP as well as in the stomach. The keratin expression pattern showed alterations depending on the experimental conditions.
9,10-Dimethyl-1,2-benzanthracene↗
Comparison of arteriolar blood flow in the hamster cheek pouch at two different oxygen tensions.
Red cell velocity and diameter were measured in arterioles of the hamster cheek pouch microvasculature. The cheek pouch tissue was exposed to two different oxygen tensions, PO2 less than 30 mmHg and PO2 greater than 150 mmHg. Blood flow was calculated from velocity and diameter measurements and was found to be significantly reduced (44%) when cheek pouch was exposed to room oxygen superfusant. This reduction was the combined result of a significant decrease in both diameter (17%) and red cell velocity (17%) as compared to the measurements during the initial low oxygen period.
Animals↗
Effect of chlorhexidine on the hamster cheek pouch. Microcirculation and penetration studies.
The application of chlorhexidine gluconate on the intact cheek pouch of hamsters led to an immediate increase of flow velocity determined in venules beneath the epithelium. The application of [14C]chlorhexidine on the intact cheek pouch led to accumulation of labeled material in the liver and kidneys. Both findings indicate that penetration of the drug occurred through the epithelium of the cheek pouch.
Absorption↗
Electrocardiographic recordings for assessing survival of cardiac allografts in the hamster cheek pouch.
Techniques for the recording of electrical events associated with contraction of allografted myocardium in the cheek pouch of inbred hamsters have been developed. The results of such recordings have been useful in assessing contractility and viability of the graft. The degree of tolerance to cardiac allografts in cheek pouches of inbred hamsters appears to be a function of histocompatibility and not "immunological privilege" of the cheek pouch.
Animals↗
A light, transmission and scanning electron microscope study of snuff-treated hamster cheek pouch epithelium.
The effects of smokeless tobacco (snuff) on hamster cheek mucosa were studied by light microscopy, transmission (TEM) and scanning electron microscopy (SEM). Two grams of commercially available smokeless tobacco were placed into the blind end of the right cheek pouch of each experimental animal, once a day and five days a week for 24 months. The control animals did not receive smokeless tobacco. After 24 months treatment with smokeless tobacco, hamster cheek mucosal epithelium lost its translucency and had become whitish in color. By light microscopy hyperorthokeratosis, prominent granular cell layers with increased keratohyalin granules and hyperplasia were seen. At the ultrastructural level, wider intercellular spaces filled with microvilli, numerous shorter desmosomes, many thin tonofilament bundles, increased number of mitochondria, membrane coating granules and keratohyalin granules were seen in snuff-treated epithelium. The changes in the surface of the epithelium as seen by SEM were the development of an irregular arrangement of the microridges and the disappearance of the normal honeycomb pattern. The microridges were irregular, widened and surrounded the irregular elongated pits. Some smooth areas without microridges and pits were also seen. The long-term histological, TEM and SEM changes induced by smokeless tobacco treatment of the epithelium are well correlated with each other and were similar to those reported in human leukoplakia without dyskeratosis. They imply changes of pathological response resulting from topically applied snuff.
Animals↗
Changes in keratin expression during 7,12-dimethylbenz[a]anthracene-induced hamster cheek pouch carcinogenesis.
This study was undertaken to explore the expression of keratins in the hamster cheek pouch carcinogenesis model, using monospecific keratin antibodies and a technique that allows immunoblotting analysis of tissues embedded in paraffin. Changes in keratin expression were correlated with histopathological changes and with the expression of the enzyme gamma-glutamyl transpeptidase. The right cheek pouch of 20 male golden Syrian hamsters was treated with 0.5% 7,12-dimethylbenz[a]anthracene for 16 weeks. As previously described by other laboratories, this treatment resulted in hyperplastic and dysplastic lesions and benign and malignant tumors. The keratins assayed in this study were K14 (Mr 55,000), K1 (Mr 67,000), and K13 (Mr 47,000). The normal hamster cheek pouch epithelium expressed K14 in the basal layer and K13 in the suprabasal and differentiated layers, whereas K1 was not detected by either immunohistochemistry or immunoblotting. Concomitant with 7,12-dimethylbenz[a]anthracene-induced hyperplasia, there were some topographical alterations in the distribution of K14. In this case, K14 was no longer restricted to the basal layer but was also expressed in differentiated cells. The same pattern was also observed in dysplastic lesions and in squamous cell carcinoma. Furthermore, expression of the K13 differentiation-associated keratin was preserved in this hyperplastic epithelium during all the stages of carcinogenesis, including either anaplastic or differentiated areas. In contrast, after 2 weeks of 7,12-dimethylbenz[a]anthracene treatment, K1 expression started as a weak and patchy pattern in suprabasal cells, becoming stronger and more homogeneous at 8 and 16 weeks of treatment. However, K1 was almost absent in squamous cell carcinoma, where only small very well differentiated areas were stained. We also observed gamma-glutamyl transpeptidase-positive foci in earlier stages of carcinogenesis, concomitant with the expression of the K1 keratin. However, it was not possible to find a perfect topographical correspondence between the two events. Alterations in the pattern of keratin expression appear to be a common feature during the development of squamous cell carcinoma in different systems and could be an excellent tool to study carcinogenesis and chemoprevention.
9,10-Dimethyl-1,2-benzanthracene↗
[Epitheliomas of the retro-molar trigone and of the inside surface of the cheeks (author's transl)].
The authors have made a study of 53 cases of tumours of the retro-molar trigone and of the internal surface of the cheeks which were treated between 1959 and 1972; these were malphigian epitheliomas except for one case of cylindroma. The research is concerned with the choice of methods and the therapeutic indications. Retro-molar trigones call for combined telecobaltherapy-electrontherapy;--curie-therapy is too difficult in this area. Electrontherapy may be used on alternate days with telecobaltherapy or as a booster dose after external irradiation by cobaltherapy. In cases of epitheliomas of the cheek, curietherapy or electrontherapy may be used after external irradiation or in isolation for tumours which are small in size. Therapeutic results are satisfactory in lesions at the outset (7/8 and 7/9), for T1-T2. For advanced lesions T3 of the trigone (6/16) and especially for those of the internal surface of the cheeks (2/9), the success rate is considerably lower; in lesions of the T4 type, a palliative effect was obtained but without any definite improvement.
Adult↗