Acclimation responses to high light by Guazuma ulmifolia Lam. (Malvaceae) leaves at different stages of development.

The re-composition of deforested environments requires the prior acclimation of seedlings to full sun in nurseries. Seedlings can overcome excess light either through the acclimation of pre-existing fully expanded leaves or through the development of new leaves that are acclimated to the new light environment. Here, we compared the acclimation capacity of mature (MatL, fully expanded at the time of transfer) and newly expanded (NewL, expanded after the light shift) leaves of Guazuma ulmifolia Lam. (Malvaceae) seedlings to high light. The seedlings were initially grown under shade and then transferred to full sunlight. MatL and NewL were used for chlorophyll fluorescence and gas exchange analyses, pigment extraction and morpho-anatomical measurements. After the transfer of seedlings to full sun, the MatL persisted and acclimated to some extent to the new light condition, since they underwent alterations in some morpho-physiological traits and maintained a functional electron transport chain and positive net photosynthesis rate. However, long-term exposure to high light led to chronic photoinhibition in MatL, which could be related to the limited plasticity of leaf morpho-anatomical attributes. However, the NewL showed a high capacity to use the absorbed energy in photochemistry and dissipate excess energy harmlessly, attributes that were favoured by the high structural plasticity exhibited by these leaves. Both the maintenance of mature, photosynthetically active leaves and the production of new leaves with a high capacity to cope with excess energy were important for acclimation of G. ulmifolia seedlings.

Effects of habitual aerobic exercise on the relationship between intramyocellular or extramyocellular lipid content and arterial stiffness.

The accumulation of intramyocellular lipid (IMCL) and extramyocellular lipid (EMCL) is associated with arterial stiffness in middle-aged and older adults. Habitual aerobic exercise induces the improvement of arterial stiffness with reduction in fat accumulation. However, the relationship between aerobic exercise-induced changes in muscular lipids and arterial stiffness remains unclear. The purpose of this study was to investigate whether habitual aerobic exercise-induced changes in IMCL and EMCL content would lead to an improvement of arterial stiffness. First, in a cross-sectional study, we investigated whether cardiorespiratory fitness level affects the association between IMCL or EMCL content and arterial stiffness in 60 middle-aged and older subjects (61.0±1.3 years). Second, in an intervention study, we examined whether aerobic exercise training-induced changes in IMCL and EMCL content are associated with a reduction in arterial stiffness in 18 middle-aged and older subjects (67.0±1.7 years). In the cross-sectional study, IMCL content was negatively correlated with brachial-ankle pulse wave velocity (baPWV) (r=-0.47, P<0.05), whereas EMCL content was positively correlated with baPWV (r=0.48, P<0.05) in the low-fitness group, but was not correlated in the high-fitness group. Furthermore, 8-week aerobic exercise training in older adults increased IMCL content and reduced EMCL content. The training-induced change in baPWV was negatively correlated with training-induced changes in IMCL but was positively correlated with training-induced changes in EMCL. These findings suggest that aerobic exercise training-induced changes in IMCL and EMCL content may be related to a reduction in arterial stiffness in middle-aged and older adults.

Elevated pentraxin 3 level at the early stage of exercise training is associated with reduction of arterial stiffness in middle-aged and older adults.

Regular exercise improves aging-induced deterioration of arterial stiffness, and is associated with elevated production of pentraxin 3 (PTX3) and anti-inflammatory as well as anti-atherosclerotic effects. However, the time-dependent effect of exercise training on arterial stiffness and PTX3 production remains unclear. The purpose of this study was to investigate the time course of the association between the effects of training on the circulating PTX3 level and arterial stiffness in middle-aged and older adults. Thirty-two healthy Japanese subjects (66.2±1.3 year) were randomly divided into two groups: training (exercise intervention) and sedentary controls. Subjects in the training group completed 8 weeks of aerobic exercise training (60-70% peak oxygen uptake (VO2peak) for 45 min, 3 days per week); during the training period, we evaluated plasma PTX3 concentration and carotid-femoral pulse wave velocity (cfPWV) every 2 wk. cfPWV gradually declined over the 8-week training period, and was significantly reduced after 6 and 8 week of exercise intervention (P<0.05). Plasma PTX3 level was significantly increased after 4 weeks of the intervention (P<0.05). In addition, the exercise training-induced reduction in cfPWV was negatively correlated with the percent change in plasma PTX3 level after 6 week (r=-0.54, P<0.05) and 8 weeks (r=-0.51, P<0.05) of the intervention, but not correlated at 4 weeks. Plasma PTX3 level was elevated at the early stage of the exercise training intervention, and was subsequently associated with training-induced alteration of arterial stiffness in middle-aged and older adults.

Adverse effects of coexistence of sarcopenia and metabolic syndrome in Japanese women.

BACKGROUND/OBJECTIVES: Little information is available regarding the interactions of sarcopenia and metabolic syndrome (MetS) in the risks of these age-associated diseases in women. The present cross-sectional study was performed to investigate whether the coexistence of sarcopenia and MetS further increases the risks of lifestyle-related diseases in Japanese women. SUBJECTS/METHODS: Healthy Japanese women (n=533) aged 30-84 participated in this study. MetS was defined as higher body mass index, fasting plasma glucose, systolic or diastolic blood pressure and blood lipid abnormalities. Appendicular muscle mass and bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry. The criterion of low muscle mass and strength defined median skeletal muscle index (appendicular muscle mass/height², kg/m²) and handgrip strength. RESULTS: Two-way ANCOVA with adjustment for age, body fat percentage and whole-body lean tissue mass indicated that sarcopenia and MetS interacted to produce a significant effect on HbA1c, systolic blood pressure, triglycerides and brachial-ankle pulse wave velocity in Japanese women. The systolic blood pressure, triglycerides and brachial-ankle pulse wave velocity were significantly higher in women with coexisting sarcopenia and MetS than in healthy controls or in those with sarcopenia or MetS alone. The HbA1c in the coexisting sarcopenia and MetS group was higher than in healthy controls and sarcopenia subjects. CONCLUSIONS: The coexistence of sarcopenia and MetS further increases the risks of cardiovascular diseases, such as type 2 diabetes mellitus, hypertension, arterial stiffness and hyperlipidemia even adjustment of age and body composition in adult Japanese women.

Mitochondrial macrohaplogroup associated with muscle power in healthy adults.

The present study was undertaken to examine the effect of mitochondrial haplogroups on aerobic and anaerobic performance phenotypes such as maximum oxygen consumption, muscle power, and muscle mass. We recruited 474 healthy Japanese individuals and measured their physical performance phenotypes such as peak oxygen uptake, muscle power, and muscle mass. The genotypes for 186 polymorphisms in the mitochondrial DNA were determined, and the haplotypes were classified into 2 macrohaplogroups (i. e., N and M) and 12 haplogroups (i. e., F, B, A, N9a, N9b, M7a, M7b, G1, G2, D4a, D4b, and D5). When we compared the 2 major Japanese macrohaplogroups, leg extension power (P=0.0395), leg extension power based on body weight (P=0.0343), and vertical jump performance (P=0.0485) were significantly higher in subjects with mitochondrial macrohaplogroup N than in those with macrohaplogroup M. However, peak oxygen uptake was similar between the 2 groups. When we analyzed the 12 haplogroups, all of the measured parameters were similar among them. In conclusion, mitochondrial macrohaplogroup N may be one of the determinant factors of anaerobic physical performance phenotype such as muscle power.

A cross-sectional study of sarcopenia in Japanese men and women: reference values and association with cardiovascular risk factors.

In this study of Japanese men and women, we determine reference values for sarcopenia and test the hypothesis that sarcopenia is associated with risk factors for cardiovascular disease, independent of waist circumference. A total of 1,488 Japanese men and women aged 18-85 years participated in this study. Appendicular muscle mass (AMM) was measured by dual-energy X-ray absorptiometry. Reference values for classes 1 and 2 sarcopenia (skeletal muscle index: AMM/height2, kg m-2) in each sex were defined as values one and two standard deviations below the sex-specific means of reference values obtained in this study from young adults aged 18-40 years. The reference values for class 1 and class 2 sarcopenia were 7.77 and 6.87 kg m-2 in men and 6.12 and 5.46 kg m-2 in women. In subjects both with class 1 and class 2 sarcopenia, body mass index and % body fat were significantly lower than in normal subjects. Despite whole-blood glycohaemoglobin A1c in men with class 1 sarcopenia was significantly higher than in normal subjects, and brachial-ankle pulse wave velocity in women both with class 1 and class 2 sarcopenia were significantly higher than in normal subjects, using one-way ANCOVA with adjustment for the covariate of waist circumference. Although sarcopenia is associated with thin body mass, it is associated with more glycation of serum proteins in men and with greater arterial stiffness in women, independent of waist circumference.

Age and cardiorespiratory fitness are associated with arterial stiffening and left ventricular remodelling.

Arterial stiffening, hypertension and left ventricular (LV) remodelling are associated with increased risk of cardiovascular disease. Cardiorespiratory fitness is associated with cardiovascular function and reduced risk of cardiovascular disease. This cross-sectional study was carried out to determine the relationships between cardiorespiratory fitness, arterial stiffness, blood pressure (BP) and LV remodelling in women. On the basis of peak oxygen uptake, a total of 159 premenopausal (young) and postmenopausal (older) women were categorized into either low (unfit) or high (fit) cardiorespiratory fitness groups. The arterial stiffness and LV remodelling were measured by brachial-ankle pulse wave velocity (baPWV) and carotid augmentation index (AI) and LV relative wall thickness (RWT). Two-way analysis of variance indicated a significant interaction between age and cardiorespiratory fitness in baPWV, carotid AI, BP and RWT. In the older group, arterial stiffness (baPWV; 1401+/-231 vs 1250+/-125 cm s(-1), P<0.01, AI; 32.9+/-9.9 vs 24.8+/-10.1%, P<0.01), systolic blood pressure (SBP) (130+/-22 vs 117+/-15 mm Hg, P<0.01) and RWT (0.47+/-0.08 vs 0.42+/-0.04, P<0.05) in fit women were lower than in unfit women. In older women, RWT was significantly related to baPWV (r=0.46, P<0.01), carotid AI (r=0.29, P<0.05), SBP (r=0.57, P<0.01) \[V(2peak) (r=-0.32, P<0.05). In young women, they were not significant correlations, except for a weak correlation between RWT and SBP (r=0.21, P<0.05). These results suggest that higher cardiorespiratory fitness is associated with lower arterial stiffness, BP and RWT in older women.

Resting energy expenditure can be assessed by dual-energy X-ray absorptiometry in women regardless of age and fitness.

OBJECTIVE: To evaluate the possibility that measurement of the magnitude and distribution of fundamental somatic heat-producing units using dual-energy X-ray absorptiometry (DXA) can be used to estimate resting energy expenditure (REE) in both young and elderly women with different aerobic fitness levels. SUBJECTS AND METHODS: Peak oxygen uptake (VO(2) peak) and REE(m) were directly measured in 116 young (age: 22.3+/-2.1 years) and 72 elderly (63.3+/-6.4 years) women. The subjects were divided into four groups according to categories of age and VO(2) peak; young: high fitness (YH, n=58); low fitness (YL, n=58); elderly: high fitness (EH, n=37) and low fitness (EL, n=35). Using DXA, systemic and regional body compositions were measured, and REE(e) was estimated from the sum of tissue organ weights multiplied by corresponding metabolic rate. RESULTS: Although there were remarkable differences in systemic and regional body compositions, no significant differences were observed between REE(m) and REE(e) in the four groups. REE(e) significantly correlated with REE(m) in elderly as well as young women; the slopes and intercepts of the two regression lines were statistically not different between the elderly and young groups (elderly: y=0.60x + 472, r=0.667; young: y=0.78x + 250, r=0.798; P<0.001, respectively). A Bland-Altman analysis did not indicate bias in calculation of REE for all the subjects. CONCLUSION: These results suggest that REE can be estimated from tissue organ components in women regardless of age and aerobic fitness.

Muscle mass and bone mineral indices: does the normalized bone mineral content differ with age?

OBJECTIVE: To investigate the relationships between regional skeletal muscle mass (SM mass) and bone mineral indices and to examine whether bone mineral content (BMC) normalized to SM mass shows a similar decrease with age in young through old age. SUBJECTS/METHODS: One hundred and thirty-eight young and postmenopausal women aged 20-76 years participated in this study and were divided into three groups: 61 young women, 49 middle-aged postmenopausal women and 28 older postmenopausal women. Muscle thickness (MTH) was determined by ultrasound, and regional SM mass (arm, trunk and leg) was estimated based on nine sites of MTH. Whole-body and regional lean soft tissue mass (LSTM), bone mineral density (BMD) and BMC (whole body, arms, legs and lumbar spine) were measured using dual-energy X-ray absorptiometry. RESULTS: Ultrasound spectroscopy indicated that SM mass is significantly correlated with site-matched regional bone mineral indices and these relationships correspond to LSTM. The BMC and BMD in older women were significantly lower than those in middle-aged women. When BMC was normalized to site-matched regional SM mass, BMC normalized to SM mass in arm and trunk region were significantly different with age; however, whole-body and leg BMC normalized to SM mass showed no significant difference between middle-aged and older postmenopausal women. CONCLUSIONS: The age-related differences in BMC were found to be independent of the ageing of SM mass in the arm and trunk region. However, differences in BMC measures of the leg and whole body were found to correspond to age-related decline of SM mass in postmenopausal women.

Gallbladder aspiration for acute cholecystitis in average-surgical-risk patients.

We conducted a retrospective case note review to assess whether or not gallbladder aspiration can be applied as a temporary measure for the treatment of acute cholecystitis in average-surgical-risk patients. Gallbladder aspiration was performed in 79 consecutive average-surgical-risk patients with acute cholecystitis, who had no indications of emergent surgery and who complained of severe colicky pain. Elective surgery became possible in 92% of patients by gallbladder aspiration. The percentage reached 97 when percutaneous cholecystostomy was added (four patients). Emergent surgery was needed in one patient suffering bile leakage following gallbladder aspiration. Colicky pain was controlled soon after the procedure in most cases. Neither major complications nor mortalities were observed in the following surgical therapies. It is suggested that gallbladder aspiration might be applied as a temporary measure for acute cholecystitis in average-surgical-risk patients, although early surgery should remain the primary choice of therapy in such patients.

Activation of WNT family expression and signaling in squamous cell carcinomas of the oral cavity.

The WNT family activates an oncogenic signaling mediated through beta-catenin and is up-regulated in a variety of malignant neoplasms. The signaling translocates beta-catenin into the nucleus and stimulates carcinoma cells in the epithelial-mesenchymal transition (EMT). However, WNT expression and signaling in oral carcinomas have not been examined. The present study focused on unveiling the involvement of WNTs in oral carcinomas, and showed that carcinoma cells express 11 of 19 WNT family members by reverse-transcription/PCR. WNT-expressing carcinoma cells exhibited increased beta-catenin levels in the cytoplasmic pool and translocation to the nucleus. The activation state of signaling correlated with the expression of membrane-type 1 matrix metalloproteinase, which degrades territorial matrices in carcinoma invasion. Immunohistochemistry disclosed that WNT3 expression and nuclear localization of beta-catenin were predominant in carcinoma cells at the invasive front. These results suggest that enhanced WNT expression and signaling accelerate the progression of carcinomas via activating EMTs and local invasiveness.

The LIM-only protein, LMO4, and the LIM domain-binding protein, LDB1, expression in squamous cell carcinomas of the oral cavity.

Carcinoma cells can lose their epithelial cell characteristics and dedifferentiate into a fibroblast-like cell during progression of a neoplasm. Aberrant expression of oligomeric transcriptional complexes contributes to progression of carcinomas. Although individual transcription factors initiating progression remain unknown, LIM-only protein (LMO) and LIM-domain binding protein (LDB) negatively regulate breast carcinoma cell differentiation. In this study, we investigated the expression of LMO4 and LDB in squamous cell carcinomas of the oral cavity. LMO4 mRNA was amplified in four of six carcinoma tissues and eight of 12 carcinoma cell lines, and LDB1 in three carcinoma tissues and 11 cell lines examined. Immunoprecipitation studies revealed that LMO4 and LDB1 interact with each other in the nuclear milieu of the carcinoma cells indicating the presence of an LMO4-LDB1-mediated transcription complex. Both LMO4 and LDB1 proteins were preferentially localised in the nuclei of carcinoma cells at the invasive front and the immunoreactivity was increased in less-differentiated carcinoma tissues (P<0.01). Carcinoma cells metastasised to the cervical lymph nodes with increased immunoreactivity compared to the primary site of neoplasm (P<0.05). These data suggest that the LMO4-LDB1 complexes may be involved in carcinoma progression possibly through dedifferentiation of squamous carcinoma cells of the oral cavity.

Circadian and photic regulation of MAP kinase by Ras- and protein phosphatase-dependent pathways in the chick pineal gland.

Chick pineal mitogen-activated protein kinase (MAPK) exhibits circadian activation and light-dependent deactivation at nighttime. Here we report that, in the chick pineal gland, levels of active forms of MAPK, MEK, Raf-1 and Ras exhibited synchronous circadian rhythms with peaks during the subjective night, suggesting a sequential activation of components in the classical Ras-MAPK pathway in a circadian manner. In contrast, the light-dependent deactivation of MAPK was not accompanied by any change of MEK activity, but it was attributed to the light-dependent activation of protein phosphatase dephosphorylating MAPK. These results indicate that the photic and clock signals regulate MAPK activity via independent pathways, and suggest a pivotal role of MAPK in photic entrainment and maintenance of the circadian oscillation.

Circadian activation of bullfrog retinal mitogen-activated protein kinase associates with oscillator function.

The vertebrate retina retains a circadian oscillator, and its oscillation is self-sustained with a period close to 24 h under constant environmental conditions. Here we show that bullfrog retinal mitogen-activated protein kinase (MAPK) exhibits an in vivo circadian rhythm in phosphorylation with a peak at night in a light/dark cycle. The phosphorylation rhythm of MAPK persists in constant darkness with a peak at subjective night, and this self-sustained rhythm is also observed in cultured retinas, indicating its close interaction with the retinal oscillator. The rhythmically phosphorylated MAPK is detected only in a discrete subset of amacrine cells despite ubiquitous distribution of MAPK throughout the retinal layers. Treatment of the cultured retinas with MAPK kinase (MEK) inhibitor PD98059 suppresses MAPK phosphorylation during the subjective night, and this pulse perturbation of MEK activity induces a significant phase delay (4-8 h) of the retinal circadian rhythm in MAPK and MEK phosphorylation. These observations strongly suggest that the site-specific and time-of-day-specific activation of MAPK contributes to the circadian time-keeping mechanism of the retinal clock system.

Correlation between the expression of methionine adenosyltransferase and the stages of human colorectal carcinoma.

Methionine adenosyltransferase (MAT) catalyzes the synthesis of S-adenosylmethionine (AdoMet) from ATP and L-methionine. AdoMet is the major methyl donor in most transmethylation reactions in vivo, and it is also the propylamino donor in the biosynthesis of polyamines. In the present study, we assessed MAT activity in human colons with colorectal carcinoma and the values were compared with those of morphologically normal adjacent mucosa. Higher levels of MAT activity were observed in the colorectal carcinoma than in the normal colon. The ratio of MAT activity in tumor tissue versus normal tissue seemed to be correlated well will the stage of the colorectal tumor. Furthermore, immunoblot analysis showed that the high levels of MAT activity observed in colorectal carcinoma were due to the increased amounts of MAT protein. Immunohistochemical analysis revealed that MAT was most abundant in goblet cells, particularly in granules in the supranuclear area of these cells. In the colorectal carcinoma tissues, MAT was strongly stained in the cancerous cells and localized in granules in the supranuclear region. The results of this preliminary study suggest that determination of the relative ratio of MAT activity in both normal and tumor regions in human colorectal carcinoma could be a clinically useful tool for determining the stage of malignancy of colorectal carcinomas.

Doxorubicin preconditioning: a protection against rat hepatic ischemia-reperfusion injury.

Doxorubicin produces clinically useful responses in a variety of human cancers. However, the toxicity of doxorubicin has limited its usefulness. This side effect is mainly due to the doxorubicin-mediated free radical formation. Administration of doxorubicin (10 mg/kg body weight) to rats intravenously induces heme oxygenase-1 (HO-1) in the liver. The levels of HO-1 protein were first detected at 6 hours and peaked at about 18 to 24 hours after the injection. It is known that HO-1 plays a protective role against the oxidative injury. Therefore, we have examined the protective effect of doxorubicin preconditioning against the hepatic ischemia-reperfusion injury. Partial hepatic ischemia was produced in the left and medium lobes for 45 minutes followed by 120 minutes reperfusion. When low doses of doxorubicin (1 mg/kg body weight) was intravenously administered to rats 2 days before the ischemia, the serum alanine transaminase (ALT) levels in the preconditioning rat were clearly improved compared with those in the rat without preconditioning. Under this situation, zinc-protoporphyrin IX, a specific inhibitor of HO-1, was injected subcutaneously to rats at 3 and 16 hours before the ischemia, the ALT levels were not improved by doxorubicin preconditioning. Histopathologic examination also supported these results. Although the HO-1 protein level was fairly low 2 days after the doxorubicin administration, significant amounts of HO-1 protein were detected. Our results indicated that the induction of HO-1 played a protective role against hepatic ischemia-reperfusion injury and that doxorubicin preconditioning is more clinically useful than other preconditioning methods.

Role of circadian activation of mitogen-activated protein kinase in chick pineal clock oscillation.

A circadian pacemaker generates a rhythm with a period of approximately 24 hr even in the absence of environmental time cues. Several photosensitive neuronal tissues such as the retina and pineal gland contain the autonomous circadian pacemaker together with the photic-input pathway responsible for entrainment of the pacemaker to the daily light/dark cycle. We show here that, in constant darkness, chick pineal mitogen-activated protein kinase (MAPK) exhibited an in vivo circadian rhythm in tyrosine phosphorylation and in enzymatic activity with a peak during subjective night. Phosphorylated and hence activated MAPK was rapidly dephosphorylated after light illumination during the nighttime when light induces a phase-shift of the pacemaker. The circadian rhythmicity in MAPK phosphorylation was also observed in the cultured pineal gland, and importantly, MAPK kinase inhibitor treatment during subjective night not only shifted the time-of-peak of MAPK phosphorylation but also induced a remarkable phase-delay of the circadian pacemaker. These results indicate an important role of MAPK for time keeping in circadian clock systems.

Characterization of N-acylation of Go alpha purified from bovine retinas.

Heterogeneous N-terminal acylation has been identified in several retinal proteins localized predominantly in the outer segments of the photoreceptor cells, but it is still unclear whether such a unique heteroacylation is determined by a photoreceptor cell-specific factor or not. Here, we characterized the N-terminal modification of bovine retinal Go alpha, which seems to be involved in the neural activities and is not detected in the photoreceptor outer segments. In the proteolytic fragments of immunoaffinity-purified retinal Go alpha, we found a single N-terminal peptide modified with myristate, and concluded that retinal Go alpha is purely myristoylated, just like brain Go alpha. This result indicates that the heteroacylation has a more restricted origin in the retina, and supports the idea that it is a photoreceptor cell-specific modification.

[Combination therapy with 5'-DFUR, MMC and CDDP in patient with far advanced gastric cancer: report of a case].

A 48-year-old man was referred to our hospital for a Borrmann 3 type advanced gastric cancer. Endoscopic biopsy disclosed poorly differentiated adenocarcinoma. Ultrasonography and CT scan revealed left hydronephrosis. Endoscopic retrograde cholangiography detected a stenosis of common bile duct at the hepatic hilum due to lymph nodal metastasis, and laparoscopy revealed peritoneal dissemination. Because the tumor was diagnosed as not for curative resection, the patient was treated by 4 courses of combination therapy with 5'-DFUR, MMC and CDDP. No adverse effect of chemotherapy was observed. As a result, lymph nodal metastasis and peritoneal dissemination were reduced. Curative intent total gastrectomy was performed, together with pancreatico-splenectomy, left hemicolectomy, cholecystectomy, and extended lymph nodal dissection. The patient is well and alive with no sign of recurrence 2 years after operation.

Cyst-like lesion of a developing tooth induced by mandibular fracture.

A dentigerous cyst-like formation in the lower canine region caused by mandibular fracture in a 10-year-old boy is reported. His medical history revealed that he had been unconscious for about 2 weeks after traumatic head injuries sustained in a traffic accident, and a complicated mandibular fracture had been left untreated until his dentist diagnosed the lesion. Eleven months after trauma, a dentigerous cyst measuring 20 mm in diameter was found in the fracture area. The lesion was enucleated and the boy's postoperative recovery was uneventful. The mass completely enveloped the developing canine, and epithelial cells proliferated into the connective tissue. However, there was no distinct epithelial lining. Small round cell infiltrations and several vessels with thrombosis were noted in the cyst wall. The cause of cyst formation was considered to be infection of the canine tooth bud and the surrounding soft tissue.