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Competition, predation, and the evolutionary significance of the cercopithecine cheek pouch: the case of Cercopithecus and Lophocebus.

Reports of cercopithecine cheek pouch use and functional significance are largely anecdotal, and to date there have been no investigations into its use by species living in closed forest habitats. Here, I report on cheek pouch use in Cercopithecus ascanius and Lophocebus albigena in the Kibale National Park, Uganda, between July-October 1997. Two hypotheses were evaluated: this feature was selected for because of its role in 1) increasing feeding efficiency via a reduction in potential feeding competition, and/or 2) reducing vulnerability to predation. Results indicate that both species were more likely to use their cheek pouches when feeding on contestable foods and, after filling cheek pouches, retreated to more densely vegetated ("safer") positions for processing food. There was no influence of age and sex on L. albigena cheek pouch use. Subadult C. ascanius cheek-pouched less frequently than adults, although there were no differences between adult males and females. There was no relationship between feeding-patch size and number of plant food items cheek-pouched in either species. However, the diameter of breast height (dbh; a measure of patch size) of trees in which C. ascanius used their cheek pouches was significantly larger than the dbh of trees in which they did not. Both species were more likely to use their cheek pouches in the presence of greater numbers of conspecifics. These data provide insight into the relationship(s) among oral anatomy and feeding efficiency, and facilitate understanding into the selection for this important oral feature in stem cercopithecines.

Adaptation, Physiological↗

Fatty acid profile of buccal cheek cell phospholipids as an index for dietary intake of docosahexaenoic acid in preterm infants.

Cheek cells (buccal epithelia) were utilized as a noninvasive index of fatty acid status in a study of the effects of n-3 long chain polyunsaturated fatty acid supplementation on visual function in preterm infants. The fatty acid profile of cheek cell phospholipids was directly correlated with the dietary docosahexenoic acid (DHA) intake of infants receiving: (i) primarily human milk; (ii) n-3 fatty acid-deficient, corn oil-based, commercial formula (CO); (iii) alpha-linolenic acid-enriched, soy oil-based, commercial formula; or (iv) experimental formula enriched with soy and marine oils providing a DHA level equivalent to that in human milk. In a subset of infants with complete cheek cell fatty acid profiles and visual function assessments, preterm infants at both 36 wk (n = 63) and 57 wk (n = 45) postconceptional age had significantly (P < 0.0005) reduced cheek cell phospholipid DHA levels in the n-3-deficient, CO-fed group compared to the other diet groups. The DHA content in cheek cell phospholipids was highly correlated (P < 0.0005) with that of both red blood cell lipids and plasma phospholipids at the 36- and 57-wk time points. The DHA content in cheek cell lipids of infants at 36 wk was significantly correlated with electroretinographic responses (r = -0.29; P < 0.03) and visual acuity (r = -0.31; P < 0.02) as measured by visual-evoked potentials (VEP). Cheek cell DHA was highly correlated (r= -0.57; P < 0.0005) with VEP acuity at the 57-wk time point. These results suggest that the fatty acid profile of cheek cells is a valid index of essential fatty acid status, can be monitored frequently, and is associated with functional parameters in infants.

Cheek↗

The fatty acid profile of buccal cheek cell phospholipids is a noninvasive marker of long-chain polyunsaturated Fatty Acid status in piglets.

The fatty acid pattern of cheek cell phospholipids has been proposed as a noninvasive marker of long-chain polyunsaturated fatty acid (PUFA) status. However, the cheek cell phospholipid fatty acid pattern has been compared only with that of plasma and erythrocytes. The objective of this study was to assess the extent to which the fatty acid profile of cheek cell phospholipids reflects that of tissue phospholipids. Piglets (n = 31; 6 d old) were fed five formula diets differing in total fat and fatty acid composition. After 14 d of consuming the assigned diets, cheek cell plasma, erythrocyte, liver, muscle, adipose tissue, retina and brain samples were collected for determination of the phospholipid fatty acid patterns. There were significant correlations between the cheek cell phospholipid content of most PUFA and the content of these fatty acids in tissue phospholipids (r = 0.509-0.951, P < 0.01). The cheek cell phospholipid content of most of the PUFA, except 20:4(n-6), reflected that of other tissue phospholipids as well as, or nearly as well as the contents of plasma and/or erythrocyte phospholipids. The correlations between the 22:6(n-3) contents of cheek cell, plasma, or erythrocyte phospholipids and those of brain and retina phospholipids were relatively poor (r = 0.596-0.737, P < 0.001). We conclude that the fatty acid pattern of cheek cell phospholipid can be used as a noninvasive marker of PUFA status, but it is not a better index than the pattern of plasma or erythrocyte phospholipids, particularly for assessing the fatty acid pattern of organs with slow fatty acid incorporation and/or turnover rates.

Adipose Tissue↗

Prominent premalar and cheek swelling: a sign of thyroid-associated orbitopathy.

PURPOSE: To describe prominent premalar and cheek swelling as a previously undescribed clinical feature of thyroid-associated orbitopathy (TAO). DESIGN: Retrospective interventional case series. METHODS: A retrospective case review of patients with prominent premalar and/or cheek swelling and TAO was undertaken. All patients who presented from March 2002 to February 2005 with complaints of premalar and/or cheek swelling in TAO were analyzed. RESULTS: Six female patients between the ages of 28 and 66 years (average, 44.2 years) who had complaints of prominent premalar and/or cheek swelling and TAO were included in the study, among 326 new patients with TAO (incidence: 1.84%). Five of the 6 patients had Graves hyperthyroidism. One initially had Hashimoto thyroiditis, which converted to Graves hyperthyroidism. In all cases, TAO preceded the thyroid disease or developed simultaneously (average time from TAO to thyroid disease was 3.0 months). No patient had received corticosteroids before premalar and/or cheek swelling. The premalar and/or cheek swelling was bilateral in all cases, but 2 of 6 were asymmetric. No diurnal fluctuation or tenderness in premalar and/or cheek swelling was noted. All improved incompletely over several months. Brow, eyelid swelling, and orbital-fat hypertrophy on radiologic examination was coincidentally noted in 5 of 6 cases. Pretibial myxedema was noted in one case. One case was associated with another autoimmune disease (rheumatoid arthritis). CONCLUSIONS: Prominent premalar and cheek swelling should be considered among the clinical features of TAO. The true incidence will become apparent as we question and examine patients more carefully regarding this entity and as we review premorbid photographs.

Adult↗

Reconstruction of through-and-through cheek defects involving the oral commissure, using chimeric flaps from the thigh lateral femoral circumflex system.

Repairing full-thickness cheek defects involving the oral commissure in the head and neck regions after tumor resection is a challenge for reconstructive surgeons. First, they are usually relatively large defects. Second, the axes of the cheek and intraoral lining are different from each other. Third, the shape and volume of the defect and the oral sphincter should be considered individually. Lateral femoral circumflex perforator flaps with at least two independent cutaneous perforators are suitable for reconstruction of such a defect in one stage. In this study, between January and December of 1999, a total of nine patients underwent reconstruction with chimeric lateral femoral circumflex perforator flaps immediately after resection of their oral cancers. The average age of the patients was 61 years (range, 42 to 74 years). The oral lining defects were between 5 x 5 cm and 6 x 12 cm in size, whereas the cheek defects were between 5 x 6 and 8 x 12 cm. Fifteen flaps were supplied by one perforator, and three flaps were supplied by two perforators. There were nine single arterial anastomoses, eight single venous anastomoses, and one double venous anastomosis. There were no total flap failures. One case of postoperative venous congestion was successfully treated by a second venous anastomosis. The average duration of hospitalization was 31.8 days (range, 18 to 49 days). The median follow-up time was 8.6 months, and all patients were alive at the time of evaluation. Six of nine patients had satisfactory or good contours of the cheek. Five of nine patients had normal deglutition. Six of nine patients had adequate oral continence. Compared with other free flaps, use of the combined (chimeric) lateral femoral circumflex perforator flaps for the reconstruction of cheek through-and-through defects involving the oral commissure has several advantages: (1) easy three-dimensional insetting, (2) a unique character suitable for the requirements of the oral lining and cheek skin to achieve good aesthetic appearance, (3) functional preservation of the oral sphincter and the resistance of gravity by use of the tensor fasciae latae, (4) minimal donor-site morbidity, (5) economic design, and (6) no need for microsurgical fabrication, because major vascular branches such as the transverse branch, the ascending branch, and the feeding branch to the rectus femoris muscle are not sacrificed in the procedure. The disadvantages of these flaps include (1) the complicated anatomy of the perforators, (2) the learning-curve requirement for their use, and (3) the occasional need for secondary venous drainage and shifts to double flaps. Although there are some difficulties, it was concluded that use of the chimeric lateral femoral circumflex perforator flaps in the selected cases is one of the good options available for the reconstruction of cheek through-and-through defects involving the oral commissure.

Adult↗

Vascular anatomy and hydrostatic pressure profile in the hamster cheek pouch.

The purpose of this study was to describe the vascular architecture and blood supply to the hamster cheek pouch and to measure the intravascular pressure distribution in the entire pouch. Previous anatomic descriptions have focused either on the vasculature of the facial region or on the microcirculation of the cheek pouch tip. Micropressures in cheek pouch capillaries, terminal arterioles, and small venules have not previously been measured. Cheek pouches were prepared for examination under an intravital microscope using both everted and noneverted methods. Microvessel diameters were measured through a video system using a video micrometer, and intravascular hydrostatic pressures were measured with a servo null micropressure system. Blood vessels in the face and pouch were traced after injection of Microfil into the external maxillary artery. The results indicate that the pouch is supplied directly or indirectly by six small arteries in the neck and face. Fifty percent of the total pressure drop across the cheek pouch vasculature occurs in the small cheek pouch arteries, suggesting that these vessels are potentially important in controlling cheek pouch blood flow. The measurements of microvascular pressures and diameters in this study help clarify apparent discrepancies in similar measurements from previous studies.

Adenosine↗

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↗

CT of the oral vestibule with distended cheeks.

PURPOSE: To evaluate patient compliance in CT examination of the oral vestibule with distended, blown-up cheeks and to determine how often such images provided additional information when disease processes in this area were suspected. MATERIAL AND METHODS: Fifty-four patients were examined with CT of the oral vestibule with distended cheeks and 16 of them had diseases where oral vestibule affection was considered possible. RESULTS: Fifty-three of 54 patients were able to perform cheek distension. Of 16 patients with possible disease involvement of the oral vestibule, additional information was thus obtained in 11 patients. CONCLUSION: When lesions involving the oral vestibule or adjacent regions are suspected, CT examination with distended cheeks is recommended as a routine procedure. The oral vestibule separates the teeth and gingiva from the buccal mucosa of the lips and cheek. On CT images of the oral region, the buccal and gingival mucosa are not separated and thus difficult to define. Problems may arise in deciding whether or not a limited tumorous or infectious lesion of the gingiva also involves the buccal region and vice-versa. We observed that images with distended, blown-up cheeks could be useful in this respect, as the air separated the gingival from the buccomasseteric region and allowed a determination of buccal distensibility. The purpose of the present report was to establish how well the patients could co-operate in performing the CT examination with distended cheeks, and how often such images provided additional information in patients with disease processes which might affect the oral vestibule.

Adolescent↗

Pharmacokinetics and pharmacodynamics of tetra(m-hydroxyphenyl)chlorin in the hamster cheek pouch tumor model: comparison with clinical measurements.

The pharmacokinetics (PK) of the photosensitizer tetra(m-hydroxyphenyl)chlorin (mTHPC) was measured by optical fiber-based light-induced fluorescence spectroscopy (LIFS) in the normal and tumoral cheek pouch mucosa of 29 Golden Syrian hamsters with chemically induced squamous cell carcinoma. Similar measurements were carried out on the normal oral cavity mucosa of five patients up to 30 days after injection. The drug doses were between 0.15 and 0.3 mg per kg of body weight (mg/kg), and the mTHPC fluorescence in the tissue was excited at 420 nm. The PK in both human and hamster exhibited similar behavior although the PK in the hamster mucosa was slightly delayed in comparison with that of its human counterpart. The mTHPC fluorescence signal of the hamster mucosa was smaller than that of the human mucosa by a factor of about 3 for the same injected drug dose. A linear correlation was found between the fluorescence signal and the mTHPC dose in the range from 0.075 to 0.5 mg/kg at times between 8 and 96 h after injection. No significant selectivity in mTHPC fluorescence between the tumoral and normal mucosa of the hamsters was found at any of the applied conditions. The sensitivity of the normal and tumoral hamster cheek pouch mucosa to mTHPC photodynamic therapy as a function of the light dose was determined by light irradiation at 650 nm and 150 mW/cm2, 4 days after the injection of a drug dose of 0.15 mg/kg. These results were compared with irradiations of the normal oral and normal and tumoral bronchial mucosa of 37 patients under the same conditions. The reaction to PDT of both types of human mucosae was considerably stronger than that of the hamster cheek pouch mucosa. The sensitivity to PDT became comparable between hamster and human mucosa when the drug dose for the hamster was increased to 0.5 mg/kg. A significant therapeutic selectivity between the normal and neoplastic hamster cheek pouch was observed. Less selectivity was found following irradiations of normal mucosa and early carcinomas in the human bronchi. The pharmacodynamic behavior of mTHPC was determined by test irradiations of the normal mucosa of hamsters and patients between 6 h and 8 days after injection of 0.5 and 0.15 mg/kg in the hamsters and the patients, respectively. The normal hamster cheek pouch showed a maximum response to irradiation 6 h after injection and then decreased continuously to no observable reaction at 8 days after injection. The reaction of the normal human oral mucosa, however, showed an increasing sensitivity to the applied light between 6 h and 4 days after mTHPC injection and then decreased again at 8 days. The hamster model with the chemically induced early squamous cell cancer in the cheek pouch thus showed some similarity to the early squamous cell cancer of the human oral mucosa considering the PK. However, a quantitative difference in fluorescence signal for identical mTHPC doses as well as a significant difference in pharmacodynamic behavior were also observed. The suitability of this animal model for the optimization of PDT parameters in the clinic is therefore limited. Hence great care must be taken in screening new dyes for PDT of early squamous cell cancer of the upper aerodigestive tract based upon observables in the hamster cheek pouch model.

Animals↗

Cheek cell phospholipids in human infants: a marker of docosahexaenoic and arachidonic acids in the diet, plasma, and red blood cells.

BACKGROUND: Assessment of essential fatty acid status requires collection of blood or adipose tissue samples. However, these invasive techniques cannot always be used in studies involving infants, young children, or subjects from whom it is difficult to obtain blood. A body tissue that is easy to access is the buccal mucosa (cheek cells). OBJECTIVE: The objective was to investigate the degree to which fatty acids of cheek cells reflect the fatty acid content of plasma, red blood cells, and the diet. DESIGN: Thirty-one infants aged 12 mo were enrolled. Five infants were fed human milk and 26 infants received formulas that provided a wide range of arachidonic acid and docosahexaenoic acid (DHA) intakes. Cheek cells were collected on a small piece of gauze by gently swabbing the inside of the cheek 3 times. Lipids were extracted from the gauze and the phospholipid fatty acid content of the cheek cells was determined. RESULTS: Cheek cell DHA and arachidonic acid in phospholipids were significantly correlated with DHA and arachidonic acid in plasma [r = 0.61 (P < 0.001) and r = 0.37 (P <0.05), respectively], red blood cells [r = 0.58 (P < 0.001) and r = 0.37 (P < 0.05), respectively], and the diet [r = 0.65 (P < 0.001) and r = 0. 51 (P < 0.01), respectively]. CONCLUSIONS: Given these correlations and the ease and noninvasive nature of this technique, cheek cell fatty acids may serve as a marker of the essential fatty acid content, especially of DHA and arachidonic acid, in plasma, red blood cells, and the diet.

Analysis of Variance↗

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↗

A search for sonoluminescence in vivo in the human cheek.

In a previous experiment, sonoluminescence was observed in aerated water, especially at the pressure antinodes in the standing-wave field of a physiotherapeutic ultrasound device (Therasonic 1030). Mammalian cells in vitro showed growth inhibition when placed at the pressure antinodes but not at adjacent pressure nodes. In the light of these results, we looked for sonoluminescence in vivo when a similar standing-wave field was set up. To detect luminescence, a light guide was held against the inner surface of the human cheek. This would channel any luminescence photons to a cooled, red-sensitive photomultiplier which would quantify the light. Direct insonation of the cheek produced no detectable luminescence. Similarly when a water bag was placed against the outer surface of the cheek, and the latter was insonated through the bag, no luminescence was detected. Sonoluminescence from the water bag was, however, detected when the bag was placed against the inner surface of the cheek, showing that absorption of sound by the cheek tissue was not preventing cavitation. Further analysis showed that if cavitation had been occurring in the cheek without detection using the system employed, then the resulting sonoluminescence would have to be at most 0.025 times as intense as that produced by an equivalent volume of aerated water.

Acoustics↗

Successful microsurgical primary replantation of an amputated cheek.

Standard secondary reconstruction procedures are usually applied for the amputation of facial soft tissue, although these procedures lead to unsatisfactory results: in case of an avulsed cheek, a number of important vital cheek functions cannot be restored. More importantly, patients with artificial cheeks often face considerable psychological and social difficulties. Therefore, it appeared to be of interest to conserve soft tissue amputated from the face and to perform a replantation, despite the known problem that cheek veins cannot be re-anastomosed, especially in avulsion injuries. Here, we report a successful microsurgical cheek replantation in a 55-year-old female patient, who had lost cheek soft tissue together with parts of her mouth.

Amputation, Traumatic↗

Improvement of neck and cheek laxity with a nonablative radiofrequency device: a lifting experience.

OBJECTIVE: Laxity of cheek and neck skin is a common cosmetic complaint of patients as they age. Improvement of skin laxity can be difficult to achieve without invasive surgical lifting procedures. The object of this study was to evaluate the safety and efficacy of a novel nonablative radiofrequency device in the treatment of cheek and neck laxity. METHODS: Fifty patients (skin phototypes I to IV) with mild-to-moderate cheek laxity (n=30) or neck laxity (n=20) received one treatment with a radiofrequency device (ThermaCool; Thermage Corp., Hayward, CA). Topical anesthetic cream was applied under occlusion for 60 minutes before treatment of the skin extending laterally and inferiorly from the nasolabial folds to the preauricular regions and mandibular ridge for treatment of the cheeks and from the mandible to mid neck for treatment of the neck. Clinical improvement of treatment areas was independently determined by three masked assessors' evaluations of comparative photographs at baseline, immediately after treatment, at 1 week, and at 1, 3, and 6 months after treatment using a quartile grading scale (0=less than 25%, 1=25% to 50%, 2=51% to 75%, 3=more than 75% improvement). Patient satisfaction surveys were also obtained at each follow-up visit. RESULTS: Significant improvement in cheek and neck skin laxity was observed in the majority of patients. Patient satisfaction scores paralleled the clinical improvements observed. Side effects were mild and limited to transient erythema, edema, and rare dysesthesia. No scarring or pigmentary alteration was seen. CONCLUSIONS: Noninvasive radiofrequency bulk dermal heating of skin can achieve safe and effective tissue tightening of the cheeks and neck. Although tightening continued to be evident 6 months after a single treatment, the longevity of clinical results has yet to be determined.

Cheek↗

Cytochrome P-450 omega-hydroxylase senses O2 in hamster muscle, but not cheek pouch epithelium, microcirculation.

The goal of this study was to investigate the role of cytochrome P-450 omega-hydroxylase in mediating O2-induced constriction of arterioles in the microcirculation of the hamster. Male Golden hamsters were anesthetized with pentobarbital sodium, and the cremaster muscle or cheek pouch was prepared for observation by intravital microscopy. Arteriolar diameters were measured during elevations of superfusate PO2 from approximately 5 to 150 mmHg. Arteriolar responses to elevated PO2 were determined in the cremaster muscle, in the retractor muscle where it inserts on the cheek pouch, and in the epithelial portion of the cheek pouch. Elevation of superfusion solution PO2 caused a vigorous constriction of arterioles in the cremaster and retractor muscles and in the epithelial portion of the cheek pouch. Superfusion with 10 microM 17-octadecynoic acid, a suicide substrate inhibitor of cytochrome P-450 omega-hydroxylase, and intravenous infusion of N-methylsulfonyl-12,12-dibromododec-11-enamide, a mechanistically different and highly selective inhibitor of cytochrome P-450 omega-hydroxylase, caused a significant reduction in the magnitude of O2-induced constriction of arterioles in the cremaster and retractor muscles. However, arteriolar constriction in response to elevated PO2 was unaffected by 17-octadecynoic acid or N-methylsulfonyl-12,12-dibromododec-11-enamide in the epithelial portion of the cheek pouch. These data confirm that there are regional differences in the mechanism of action of O2 on the microcirculation and indicate that cytochrome P-450 omega-hydroxylase senses O2 in the microcirculation of hamster skeletal muscle, but not in the cheek pouch epithelium.

Amides↗

Regional lymph node metastasis created by partial excision of carcinomas induced in hamster cheek pouch with 9,10-dimethyl-1,2-benzanthracene.

The feasibility of using the hamster cheek pouch/dimethyl-benzanthracene (DMBA) system as an experimental model of lymphatic metastasis was investigated. Forty male Syrian golden hamsters treated with DMBA were divided into two equal groups--one with surgical excision of their tumors and a control group without tumor excision. In the excision group, the animals received three applications/week to the left cheek pouch of 0.3% DMBA in acetone for 14 weeks. Following a three-week observation period, the tumors in the pouch were excised at their base, and the animals were killed after four weeks of further observation. In the control group, the animals were treated for 14 weeks in a manner similar to that used for the excision group, left for seven weeks without treatment, and then killed. Cheek pouches with tumors and cervical lymph nodes were processed for histological examination. All of the animals, both with and without metastasis, had borne squamous cell carcinomas (SCC) in their treated cheek pouches. Histologically, seven out of 16 animals in the excision group showed metastatic deposits of SCC confined to the left cervical lymph nodes, while in the control group, metastasis was not found in any of the 19 animals with SCC in their cheek pouches. The results demonstrate that surgical excision of the hamster cheek pouch carcinoma is efficient in producing unequivocal lymph node metastasis.

9,10-Dimethyl-1,2-benzanthracene↗

Experimental dermatophytosis in hamsters inoculated with Trichophyton mentagrophytes in the cheek pouch.

This study presents the results of T. mentagrophytes inoculation in the cheek pouch of the hamster, an immunologically privileged site. Forty two animals were used: 21 inoculated with 10(6) fungi in the cheek pouch (group 1) and 21 inoculated initially with 10(6) fungi in the foot pad and 15 days later in the cheek pouch, with the same amount of fungi (group 2). Animals were sacrificed at 20 hours, 3, 7, 14, 30, 60, and 120 days; samples from inoculated cheek pouch, and foot pads submitted to the foot pad test (FPT), were collected. Independent of group and time of evolution of infection, animals did not develop delayed hypersensitivity evaluated through the FPT. The pre-inoculation of fungi in the foot pad did not change the morphology of lesions induced in the cheek pouch. Therefore, in animals of group 1 and 2, the introduction of the fungus in the cheek pouch resulted in focal lesion composed of a sterile acute inflammatory infiltrate, with abscess formation that evolved to a macrophagic reaction, and later to resolution even in the absence of immune response detectable by FPT. Our results indicate that in spite of the important role of the immune response in the spontaneous regression of dermatophytosis, other factors are also an integral part in the defense against this fungal infection.

Animals↗

Microvascular permeability and blood flow in atrial homografts in the hamster cheek pouch.

Atrial heart tissue grafts from newborn golden hamsters were transplanted into cheek pouches and were studied using intravital microscopic techniques. The smallest microvessels in the homografts showed a mean diameter of 13.3 +/- 1.1 micron (mean +/- S.E.M.) thus being in the dimensional range of terminal arterioles of the fourth branching order (A4, 14.0 +/- 2.1 micron) in normal cheek pouch tissue. Arteriolar red cell velocity was measured using a modified dual slit method. Volumetric blood flow was calculated and seen to be similar in terminal cheek pouch arterioles (116 +/- 34 pl/s) and in the graft vessels (119 +/- 26 pl/s). The responsiveness to topically applied norepinephrine of the graft vessels was found to be significantly lower than in cheek pouch arterioles. Microvascular permeability studied with FITC-dextrans (intravenous application) revealed significantly higher intensity values in the homografts as compared with the surrounding cheek pouch tissue. The difference was most pronounced for the largest tracer molecules used (Mw 150 000). This phenomenon is most probably due to an increased macromolecular permeability of the microvessels in the graft. The present findings point towards functional differences between the transplant vessels and cheek pouch capillaries.

Animals↗