Abnormal expression of bcl-2 and bax in rat tongue mucosa during the development of squamous cell carcinoma induced by 4-nitroquinoline 1-oxide

4-Nitroquinoline 1-oxide (4NQO)-induced rat tongue carcinogenesis is a useful model for studying oral squamous cell carcinoma. The aim of this study was to investigate the expression of bcl-2 and bax during tongue carcinogenesis induced by 4NQO. Male Wistar rats were distributed into three groups of 10 animals each and treated with 50 ppm 4NQO solution through their drinking water for 4, 12 or 20 weeks. Ten animals were used as negative control. Although no histological changes were induced in the epithelium after 4 weeks of carcinogen exposure, bcl-2 and bax were over-expressed (P < 0.01) in all layers of the 'normal' epithelium. The expression levels were the same in all layers of epithelium for both the antibodies used (bcl-2 or bax). In dysplastic lesions at 12 weeks following carcinogen administration, the levels of bcl-2 and bax expression did not increase when compared to negative control with the immunoreactivity for bcl-2 being restricted to the superficial layer of epithelium. In well-differentiated squamous cell carcinoma induced after 20 weeks of treatment with 4NQO, bcl-2 was expressed in some cells of tumour islands. on the other hand, immunostaining for bax was widely observed at the tumour nests. The labelling index for bcl-2 and bax showed an increase (P < 0.05) after only 4 weeks of 4NQO administration. In conclusion, our results suggest that abnormalities in the apoptosis pathways are associated with the development of persistent clones of mutated-epithelial cells in the oral mucosa. Bcl-2 and bax expression appears to be associated with a risk factor in the progression of oral cancer.

Effect of lesion age, humidity, and fungicide application on sporulation of Alternaria alternata, the cause of brown spot of tangerine

Alternaria brown spot, caused by Alternaria alternata, causes yield losses and fruit blemishes on many tangerines and their hybrids in most citrus areas of the world where susceptible cultivars are grown. Although the conditions affecting infection and disease severity are known, little information is available on inoculum production on infected tissue. We found that sporulation on leaves began about 10 days after symptoms developed, was abundant from 20 to 40 days, and declined thereafter. Conidial production was far greater on leaf than on fruit or twig lesions. Spore production per unit area of leaf lesion was greater on the more susceptible hybrids, Minneola and Orlando tangelos, than on the less susceptible Murcott tangor. At 74% relative humidity, conidial production on leaf lesions was low, but it was abundant at 85, 92.5, 96, and 100%. Application of Q(o)I or copper fungicides, but not ferbam, suppressed sporulation on leaf lesions for about 14 to 21 days after application. Additional applications did not appear to be more effective than a single spray in reducing inoculum production.

Paradental cyst: Report of two cases

Background: the paradentat cyst is an odontogenic lesion of inflammatory origin that has few clinical signs and symptoms apart from recurring acute episodes. A well-defined radiolucency associated with the roots or distal to the crown may be seen radiographically. The purpose of this article is to report on different aspects of two cases involving paradental cysts. In the first case, the patient complained about recurring pericoronitis. A semilunar-shaped radiolucency on the distal aspect of the mandibular third molar was noted on the periapical radiograph. In the second case, the patient's main complaint was chronic trauma of the overlying mucosa. Radiographs revealed an enlarged pericoronal space.Methods: In both cases, the mandibular third molar was extracted due to a lack of space. Lesional samples were sent for histopathologic analysis.Results: In the first case, the drainage of cystic fluid and a regular concavity were found during tooth removal. In the second case, a nodular lesion was found adhering to the disto-buccal surface of the tooth arising from the distal wall of a periodontal pocket. The histopathologic analysis revealed a hyperplastic stratified squamous epithelium with arcading lining a fibrous capsule with inflammatory infiltrate, resulting in a final diagnosis of a paradental cyst.Conclusions: the presence of a paradental cyst should be considered when recurrent inflammatory periodontal processes are associated with partially erupted vital teeth, even when characteristic radiographic findings are absent. Definitive diagnosis requires a clinicopathologic correlation incorporating surgical, radiographic, and histologic findings.

HIGH DIETARY CARBOHYDRATE AND PANCREATIC LESION

The ability of high dietary carbohydrate to induce acute pancreatitis was investigated in groups of 16,2 1-day and 15-month old rats fed different carbohydrate diets for 30 days. Significantly increased levels of serum amylase (2-fold), phospholipids (50%),phosphorus (2-fold), and lipoperoxides (8-fold) were observed in 15-month old rats fed a high-carbohydrate diet, compared to rats fed a diet with normal carbohydrate levels, indicating peroxidation of membrane lipids which caused final cell death and pancreatic lesion. Serum Cu-Zn superoxide dismutase activity was not altered. Daily administration of bovine Cu-Zn superoxide dismutase conjugated with polyediylene glycol prevented the serum level alterations and pancreatic lesions, indicating that the superoxide radical has a role in dietary carbohydrate-induced acute pancreatitis. No biochemical changes were observed in rats in which treatment was initiated on the 21st day of life indicating that this is an age-related lesion.

EFFECT OF ELECTROLYTIC AND CHEMICAL LESION BY IBOTENIC ACID OF THE AMYGDALA ON SALT INTAKE

Sodium chloride intake was studied in male Holtzman rats weighing 250-300 g submitted to electrolytic and chemical lesion of the cell bodies, not fibers of the amygdaloid complex. Sodium chloride (1.5%) intake increased in animals with electrolytic lesion of the corticomedial nucleus of the amygdala. Sodium chloride (1.5%) intake increased after ibotenic acid injection into the corticomedial nucleus of the amygdala to a larger extent (26.6 +/- 9.2 to 147.6 +/- 34.6 ml/5 days). The results indicate that sodium intake response can be induced by lesions, which involved only cell bodies. The fibers of passage of the corticomedial nucleus of the amygdala produce a water intake less consistent than that induced by ibotenic acid, which is more acute. The results show that cell bodies of this region of the amygdala are involved in the control of sodium chloride intake.

EFFECT OF TESTOSTERONE ON THE PRESSOR-RESPONSE TO COMMON CAROTID OCCLUSION IN GONADECTOMIZED CONSCIOUS MALE-RATS WITH LESION OF THE MEDIAN-EMINENCE

The influence of testosterone on the development of the pressor response to common carotid occlusion was investigated in control and median eminence-lesioned male rats. In control rats (N = 9), gonadectomy performed 21 days before the experiments reduced by 22% (from 51 +/- 2 to 40 +/- 2 mmHg) and treatment with testosterone (300-mu-g for 4 days before the measurements) increased the initial peak pressor response (from 51 +/- 2 to 57 +/- 2 mmHg) which depends on carotid innervation. The maintained response which is of central origin (probably ischemic) was less affected. In nongonadectomized rats (N = 6), lesions of the median eminence (6 days) decreased the initial peak by 19% (from 52 +/- 2 to 42 +/- 3 mmHg) and the maintained response by 56% (from 32 +/- 2 to 14 +/- 1 mmHg). Sham-operated rats served as controls. In gonadectomized animals (N = 6) the lesion reduced only the maintained response (from 23 +/- 2 to 11 +/- 1 mmHg). Testosterone supplementation restored the maintained response but did not alter the initial peak. These results indicate that the pressor response to common carotid occlusion in male rats is modulated by testosterone and that the depression in the maintained response caused by median eminence lesion can be reversed by steroid supplementation.

Effect of high laryngeal mask airway intracuff pressure on the laryngopharyngeal mucosa of dogs

Objectives: To evaluate the effect of increased of laryngeal mask airway (LMA) intracuff pressures on the laryngopharyngeal mucosa. Study Design: Animal model. Methods: Sixteen mixed-breed dogs were randomly allocated to two groups, G1 (intracuff volume, 30 mL; n = 8) and G2 (intracuff volume, 54 mt; n = 8), to produce, respectively, high or very high intracuff pressures. Anesthesia was induced and maintained with pentobarbital. Intracuff pressures were measured immediately after insertion and inflation of a No. 4 laryngeal mask airway (LMA) and 30, 60, 90, and 120 minutes thereafter. The dogs were euthanized, and biopsy specimens from eight predetermined areas of the laryngopharynx in contact with LMA cuff were collected for light microscopic (LM) and scanning electron microscopic (SEM) examination. Results: Initial LMA cuff inflation in G1 and G2 resulted in intracuff pressures of 119 mm Hg +/- 4 mm Hg and 235 mm Hg +/- 13 mm Hg, respectively. Over a 2-hour period, the intracuff pressure decreased significantly in G1 (P < .001) and G2 (P < .01), and there was a significant difference between the groups over time (P < .001). The LM study of laryngopharyngeal mucosa in both groups showed mild congestion in the subepithelial layer. There were no differences between the groups (P > .10) or among the areas sampled (P > .10). In some areas of G2, the SEM study showed epithelial desquamation that was more intense than that in GI. Conclusions: the increase in LMA intracuff pressure caused only mild alterations in the laryngopharyngeal mucosa of the dog.