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PubMed1994

Effects of nicotine and tobacco-specific nitrosamines on hamster cheek pouch and gastric mucosa.

Fifty-two hamsters were divided into 6 groups and their cheek pouches treated with either 0.01% NNN, 0.01% NNN and 6% nicotine, 0.01% NNK, 0.01% NNK and 6% nicotine, 6% nicotine, or sesame oil. After painting each pouch 3 times per week for 13 months, the animals were killed and specimens from the cheek pouch and forestomach examined. Cheek pouch epithelium showed more frequent histologic changes, including hyperplasia, hyperkeratosis and, in one animal, moderate dysplasia, when nicotine was combined with NNN than after treatment with NNN (or nicotine) alone. There was a higher frequency of hyperplasia with hyperkeratosis in the forestomach when nicotine was combined with NNK than following NNK, or nicotine treatment alone, and squamous cell papillomas were evident in animals treated with both NNK and nicotine. These results suggest that in mucosal tissues nicotine may enhance the effect of weak carcinogens such as the nitrosamines.

Animals↗
PubMed1996

The effect of sodium lauryl sulphate on the expression of cytokeratin mRNA in hamster cheek pouch epithelium.

The effect of sodium lauryl sulphate (SLS) on cytokeratin (CK) gene expression in hamster cheek pouch epithelium was studied with a hybridohistochemical technique. Using specific human anti-sense RNA probes, the plausible hamster mRNA counterparts for these human CK mRNAs were localized by detection of heterologous hybrids. In comparison with normal epithelium, the expression and distribution pattern of CK mRNAs in the hamster cheek pouch were obviously changed after application of SLS. There was a decreased expression of CK mRNAs in the hyperplastic basal layer, and increased expression in the hypertrophic granular layer. Strikingly, hybridization with the human CK 18 cRNA probe revealed an additionally expressed CK mRNA in the SLS-treated epithelium that was not found in the untreated epithelium. The present study indicates that cRNA probes for human CK mRNAs can be used successfully, not only to distinguish between different hamster CK mRNAs but also to investigate changes in CK gene expression upon the induction of non-neoplastic and neoplastic alterations in the hamster cheek pouch model. This may help elucidate the molecular changes involved in epithelial pathologies.

Animals↗
PubMed1994

Osmotic and other properties of isolated human cheek epithelial cells.

This study describes some biological properties of human cheek (buccal epithelial) cells, isolated by mouth wash. Yields ranged from 6.5 to 20.6 x 10(6) cells, with a mean (+/- SE) of 12.2 +/- 4.2 x 10(6) cells, which gave 0.55 +/- 0.01 x 10(6) cells/mg protein. Vital stain exclusion was similar in cells isolated in either water (89 +/- 2%) or 250 mM sucrose (87 +/- 3%). From our measurements of cell volume and electrolyte content, we estimated intracellular Na+ and K+ concentrations to be between 0.3-0.5 and 7.4-13.0 mM, respectively. In 22 adult subjects, basal, prickle, intermediate, and superficial cells represented 0.3 +/- 1.4, 51 +/- 2.4, 26 +/- 0.9, and 22.7 +/- 1.8%, respectively, of the total sample. Cheek cells exhibited a low endogenous rate of oxygen consumption, which was stimulated by glucose or succinate and inhibited by KCN or NaF. Cheek cells were osmotically stable in a wide range of media, including water. However, they exhibited shrinkage and collapse in hypertonic media, particularly polyethylene glycol.

Adult↗
PubMed1993

NK1 receptors mediate tachykinin-induced increase in microvascular clearance in hamster cheek pouch.

The purpose of this study was to determine the receptor subtype(s) that mediates tachykinin-induced neurogenic plasma extravasation in the hamster cheek pouch. Changes in microvascular clearance were quantified by counting the number of leaky sites and calculating the clearance of fluorescein isothiocyanate-dextran [mol wt 70,000 (Dextran 70)] during suffusion of the cheek pouch with substance P, neurokinin A, neurokinin B, and capsaicin. Suffusion of substance P, capsaicin, and neurokinin A, but not neurokinin B, was associated with a significant concentration-dependent increase in leaky site formation and clearance of fluorescein isothiocyanate-Dextran 70 (P < 0.05). However, the responses to substance P and capsaicin were significantly greater than those to neurokinin A. Pretreatment with the selective, nonpeptide NK1 receptor antagonist, CP-96,345, significantly attenuated substance P- and capsaicin-induced but not neurokinin A-induced responses (P < 0.05). These effects were specific, since the 2R,3R enantiomer, CP-96,344, was inactive, and CP-96,345 had no significant effect on adenosine-induced responses. We conclude that, in the hamster cheek pouch, NK1 receptors are the predominant receptors that mediate neurogenic plasma extravasation.

Animals↗
PubMed2000

Tyrosine kinase inhibitors modulate agonist-induced vasodilation in the hamster cheek pouch.

The purpose of this study was to determine whether inhibitors of tyrosine kinase attenuate vasodilation elicited by endogenously elaborated and exogenously applied nitric oxide in the in situ peripheral microcirculation. Using intravital microscopy, we found that pretreatment with genistein (1.0 microM) and tyrphostin 25 (10.0 microM), two structurally unrelated tyrosine kinase inhibitors, significantly attenuated acetylcholine-, bradykinin- and nitroglycerin-induced dilation of second-order arterioles (51 +/- 1 microm) in the in situ hamster cheek pouch (P < 0.05). Both inhibitors nearly abrogated acetylcholine-induced responses but only partially blocked bradykinin- and nitroglycerin-induced vasodilation. Genistein and tyrphostin 25 alone had no significant effects on resting arteriolar diameter and on adenosine-induced vasodilation in the cheek pouch. On balance, these data indicate that tyrosine kinase inhibitors attenuate endogenously elaborated and exogenously applied nitric oxide-induced vasodilation in the in situ hamster cheek pouch. However, the extent of tyrosine kinase inhibitor-sensitive pathway involvement in this response appears to be agonist dependent.

Acetylcholine↗
PubMed1997

Microvascular reactivity after ischemia/reperfusion in the hamster cheek pouch: beneficial effects of different oral doses of S-5682 (Daflon 500 mg).

Daflon 500 mg (S-5682) is a purified, micronized flavonoid fraction containing 90% diosmin and 10% hesperidin that is currently used to treat chronic venous insufficiency and hemorrhoidal disease. Thus, it seemed of interest to evaluate the effects of S-5682 on ischemia/reperfusion, ie, the changes in mean internal diameter and blood flow of arterioles and venules and the functional capillary density (FCD) during reperfusion after ninety minutes of total ischemia in the hamster cheek pouch microvasculature. Different doses of S-5682 (5, 20, 80, and 160 mg/kg body weight/day), suspended in 10% lactose solution or vehicle (10% lactose) were administered orally to male hamsters for ten days twice a day. The cheek pouch preparation was placed under an intravital microscope coupled to a closed-circuit TV system. A ninety-minute local ischemia was obtained by a cuff mounted around the neck of the everted pouch where it left the mouth of the hamster. Mean arteriolar and venular internal diameters were determined by means of an image-shearing device, IPM model 907; red blood cell (RBC) velocity was measured by the dual-slit photometric technique; microvessel volume flow was calculated from diameters and RBC velocities; and FCD was defined as the number of red-cell-perfused capillaries per observation field. During reperfusion, placebo-treated animals showed significant vasodilatation concomitant with a decrease in blood flow and FCD compared with preischemic values and an impairment of the myogenic response. In S-5682-treated animals, there was a significant dose-dependent improvement in all these parameters including the myogenic tonus. These results clearly demonstrated that oral administration of different doses of S-5682 for ten days improved the microvascular reactivity and FCD after ischemia/reperfusion in a dose-dependent fashion in the hamster cheek pouch microvasculature.

Animals↗
PubMed1984

Incisional biopsy and seeding in hamster cheek pouch carcinoma.

Surgical blades were contaminated by doing incisional biopsies on DMBA-induced cheek pouch carcinomas in hamsters. Contaminated blades were then used to: (1) make cytologic smears; (2) make incisions in the mucosal surface of the lower lip; (3) make incisions in the ventral surface of the tongue; (4) make incisions in the untreated left cheek pouch; and (5) make incisions in the pre-shaved back. One group of animals was killed three hr post-surgery. The second group was killed seven wk post-surgery. Tissues were excised and processed for microscopic study. Malignant cells were found in many of the incision sites of animals from the first group. In the animals of the second group, several tumors growing from the transplanted tumor cells were observed in the incision sites of the lower lips and the tongue. None was observed in the incision sites of the left cheek pouch or the back. Cervical lymph node metastases were found in approximately 50% of the animals of the second group.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1984

Extensibility characteristics of human cheek--visco-elastic properties.

Using a hydraulic bellows system mounted on a maxillary partial denture, continuous force-displacement data were taken in an edentulous area in the maxillary bicuspid-molar region on ten adults. Both loading and unloading force-displacement curves showed three segments. Two visco-elastic properties - hysteresis and relaxation - were consistently evident. The maximum difference in force-magnitude of the hysteresis loop was 1.02 g. A pre-conditioning phenomenon of the cheek tissue, evidence by a reduction of the area of the hysteresis loop, was observed in a series of repeated runs. The significance of the study was that: (1) in some individuals, the cheek could be displaced, by expansion of the molars, up to 1 mm into a second stable position; and (2) the relaxation phenomenon suggests a limited adjustive capacity in cheek stiffness.

Adult↗
PubMed1991

The "numb cheek-limp lower lid" syndrome.

A patient developed isolated numbness, 1st confined to the lateral nose and upper lip, but later involving the cheek, lower lip, upper gingiva, and the palate. This numbness was later associated with paresis of the muscles of the upper lip and angle of the mouth and with ipsilateral lower lid droop (the "numb cheek-limp lower lid" syndrome). Squamous cell carcinoma was discovered infiltrating the infraorbital nerve and distal branches of the facial nerve. Cheek numbness associated with lower eyelid or upper lip weakness may herald a neoplasm affecting the infraorbital nerve and distal facial nerve branches.

Aged↗
PubMed1998

Studies on development of dosage forms for pediatric use (V) oral mucosal irritation study of gummi drugs in hamster cheek pouch.

In the present study we investigated irritation of the oral mucosa and the safety of gummi drugs containing acetaminophen (AAP). The oral mucosae of hamsters were macroscopically examined for any evidence of irritation after gummi drugs were inserted into the cheek pouch and left there for 1 h. The cheek pouch tissue was also macroscopically and microscopically examined 24 h after gummi drugs were withdrawn from the cheek pouch. As a result, no evidence of irritation was found macroscopically 1 h after insertion, or macroscopically and microscopically 24 h after the withdrawal of the gummi drugs or placebos as compared with negative controls (saline). Considering these results, the gummi drugs administered in the present study produced no irritation to the oral mucosa.

Acetaminophen↗
PubMed1986

Studies on drug absorption from oral cavity: physicochemical factors affecting absorption from hamster cheek pouch.

A new experimental method using a hamster cheek pouch in vivo for studying absorption processes across the keratinized oral mucous membrane was developed and some characteristics of the oral-mucosal absorption were clarified. A positive correlation between the absorption rate and the lipophilicity was observed in 18 aromatic compounds examined. The absorption of ionizable compounds was poor in the ionized form. These results suggest that the absorption from the keratinized hamster cheek pouch is due to a passive diffusion mechanism and obeys pH-partition hypothesis. The systemic transfer of salicylic acid after intra-cheek-pouch administration could be approximated by the first-order absorption model including a lag time process and the plasma levels found were consistent with this model.

Absorption↗
PubMedDate not supplied

Histological evaluation of the lesion induced by inoculation of Leishmania mexicana in the cheek pouch of the hamster.

We have studied the role of the immune response in the morphology of the leishmaniotic granuloma induced in the cheek pouch of hamsters, an immunologically privileged site, after inoculation of 3 x 10(5) Leishmania mexicana. Animals were histologically and immunologically evaluated until 120 days after inoculation. Independent of the time of sacrifice, the animals were always non-reactors to the footpad test (FPT). At histology, the introduction of L. mexicana in the cheek pouch leads to an abscess that evolves to a granulomatous reaction rich in amastigote forms, and later it leads to resolution, even in the absence of immune response detectable by FPT. Our results demonstrate that the development of immune response is not preponderant for the control of infection induced by L. mexicana inoculated subcutaneously in the cheek pouch of the hamster. It also suggests that the macrophages present in the leishmaniotic granuloma are capable of eliminating this parasite, even in the absence of immune response evaluated by FPT.

Animals↗
PubMed1977

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↗
PubMed1975

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↗
PubMed1987

Peripheral vascular pathophysiology of Plasmodium berghei infection: a comparative study in the cheek pouch and brain of the golden hamster.

Four- to six-week-old hamsters were infected with 1.5 X 10(7) Plasmodium berghei-parasitized hamster red blood cells by intraperitoneal injection. Cheek pouch circulation was observed microscopically in the anesthetized animal; the brain and contralateral pouch were collected for histopathologic examination on days 3-12 post-challenge. Cheek pouch vascular lesions, observed in vivo, appear to involve three phenomena; early (beginning 3-4 days) adhesion of pigment-laden mononuclear cells to endothelium within venous vessels and loss of function of the small capillaries supplying the skeletal muscle fibers and, later (6-9 days), the apparent attraction of erythrocytes to venular and venous endothelium and to adherent monocytes. The aggregation of formed elements on endothelial walls leads to progressive occlusion of venules and small veins and contributes to the observed disruption of flow through capillary networks. Histopathology of the brain and pouch shows vascular changes similar to those seen in vivo; in addition, multifocal hemorrhages are seen commonly in the brain and occasionally in the pouch on postmortem. In severe disease, evidence of cerebral edema is seen in the brain. The data suggest that failure of capillary flow and disruption of venous outflow tracts by cell aggregates are central to vascular failure in both the cheek pouch and brain of the P. berghei infected hamster. This hamster model of human cerebral malaria allows the in vivo observation, still and video photomicrography, and manipulation of the peripheral vascular pathogenesis of a disease process similar to that seen in humans.

Animals↗
PubMed1998

Effect of gynostemma pentaphyllum mak on carcinomatous conversions of golden hamster cheek pouches induced by dimethylbenzanthracene: a histological study.

OBJECTIVE: To evaluate the effect of gynostemma pentaphyllum mak (GP) on carcinomatous conversions of leukoplasia of the golden hamster cheek pouch induced by dimethylbenzanthracene (DMBA). METHODS: 284 golden hamsters, ranging from 4 to 8 weeks of age, 80 to 100 grams in weight were randomly divided into three groups: control, model and experimental groups. Control group (8 hamsters) were sacrificed at week 0 and week 12 for control. Model group (123 hamsters) were pasted in bilateral cheek pouches with 0.5% DMBA, 3 times a week for establishment of experimental leukoplasia, and sacrificed at week 2 to week 9 (12-22 hamsters were sacrificed a week). Experimental group (153 hamsters) were divided into three subgroups. Subgroup A underwent simultaneous DMBA pasting and oral taking of GP, and were sacrificed at week 6 and week 9. Subgroup B underwent oral taking of GP for 12 weeks after completion of DMBA pasting. Subgroup C underwent DMBA pasting after completion of oral taking of GP for 12 weeks. RESULTS: The earliest epithelial dysplasia and carcinoma in situ occurred at week 3 and week 6 after DMBA pasting. There were significant differences between subgroup B and model group for 3 weeks' administration of DMBA (P < 0.05), and between subgroup C and model group (P < 0.01), while there was no difference between subgroup B and model group for 6 week's administration of DMBA (P > 0.05). CONCLUSIONS: GP could inhibit and reverse the carcinomatous conversions of leukoplasia of golden hamster cheek pouches, indicating its positive anticarcinogenic effect.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2004

[The design of the expanded flap for the repair of the temporal and cheek area].

OBJECTIVE: To explore the design of an expanded flap at the temporal and cheek area. METHODS: The expanded flap was used for the repair of 619 temporal and cheek defects secondary to scar, nevus or hemangioma excision. In the frontal area, the rotational flap was usually used. For the repair of the cheek, the applied flap included the rotational, advanced, and transposition flap from the neck, as well as the pedicle flap from the thoracic area. RESULTS: Eight thoracic-deltoid flaps had distal necrosis of 1 approximately 5 cm. Of them, 5 flaps were repositioned with subsequent good result; the other 3 flaps underwent skin grafting. The five facial expanded flaps showed distal necrosis of 0.5 approximately 1 cm. Of them, 4 flaps occurred delayed healing, 1 flap underwent skin grafting. Expander extrusion happened in 41 cases (6.62%), which resulted in deficiency of the expanded area. Satisfactory results were achieved in all the other cases. CONCLUSIONS: According to our experience, careful design of the flap is very important for obtainingbetter surgical results and decreasing complications.

Adolescent↗
PubMed1992

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↗