Establishment of the epithelial attachment and connective tissue adaptation to implants installed under the concept of "platform switching": a histologic study in minipigs

Aim: To validate the platform switching concept at oral implants with respect to the preservation of the alveolar crestal bone levels in an animal model. Material & methods: Five minipigs received three implants each with a 0.25mm implant/ abutment mismatch and were placed flush (T(0)), 1 mm below (T(1)) and 1 mm above (T(+1)) the alveolar bony crest, and as a control, one conventionally restored implant placed at the bone level. The implants were randomly inserted flapless into the mandible. Four months after implant insertion, the animals were sacrificed, and undecalcified block sections were obtained and used for histological analyses. Results: The mean values for peri- implant bone resorption were 1.09 +/- 0.59mm (Control), 0.51 (+/- 0.27 mm, T(0)), 0.50 (+/- 0.46 mm, T(1)) and 1.30 (+/- 0.21 mm, T (+1)), respectively. Statistically significant differences (P< 0.05) were found among the test (T(0), T(-1)) and the control sites. Control implants presented an average biologic width length of 3.20mm (+/- 0.33), with a connective tissue adaptation compartment of 1.29mm (+/- 0.53) and an epithelial attachment of 1.91 mm (+/- 0.71). T(0), T(1) and T(+1) implants presented with a mean biologic width of 1.97mm (+/- 1.20), 2.70 mm (+/- 1.36) and 2.84mm (+/- 0.90), respectively, with a connective tissue adaptation compartment of 1.21mm (+/- 0.97), 1.21 mm (+/- 0.65) and 1.50 mm (+/- 0.70) and an epithelial attachment of 0.84 mm (+/- 0.93), 1.66 mm (+/- 0.88) and 1.35 mm (+/- 0.44), respectively. Differences between the configurations were mainly associated with the length of the epithelial attachment. The epithelial attachment was significantly longer in the C sites than in T(0) (P = 0.014). However, no other differences between configurations were detected. Conclusion: If the implants are positioned at the level of the alveolar bony crest, the platform switching concept may have a minor impact on the length of the epithelial attachment (0.84 vs. 1.91 mm), while the connective tissue adaptation compartment remains relatively unaffected. Moreover, platform switching resulted in less resorption of the alveolar crest (0.58 mm).

Emprego da imunofluorescência direta no estudo das alterações de mucosa de palato, compatíveis com candidíase atrófica crônica, em indivíduos portadores de próteses dentárias totais muco-suportadas.

Histopathology by hematoxilin-eosin (HE) and periodic acid Schiff (PAS), concomitant direct immunofluorescence (DI) against total human immunoglobulins and against Candida albicans, was effectuated in 25 persons dentures wearers. In 5 persons without chronic athrofic candidiasis (CAC) clinical signals in the palate the HE showed wise inflammatory elements in the connective tissue and the PAS marked the continuous basal layer, the intra-cellular grains of granular layer and the uniform parakeratin on epithelial surface. In 20 others, with palatal signals of CAC, in the HE was frequent the features encountered in Candida infected and PAS revealed, beside descontinuous lamina basal and epithelial surface covered by tide and discontinuous parakeratin, the presence of round bodies few largers that presents in the granular layer, casually isolated in the medial portion of ret pegs and connective papillae. In the first 5 persons the DI against total human immunoglobulins not showed signals of the humoral immunologic phenomena, the same was valid to others 20 patients with CAC clinical aspects. However the DI with conjugate against C. albicans in the 20 cases with CAC signals revealed suitable aspects of the structures assumed by Candida in tissues. Cultures of samples obtained of the persons with CAC signals was positive in 100% to Candida, 70% presumptively albicans, against 80% of positiviness to generus Candida, 67% presumptively albicans, in the persons without CAC signals.

In vitro characterization of intra-generic inhibition of growth in Salmonella typhimurium

The intra-generic inhibition of bacterial growth observed previously in vivo and in vitro with strains of Salmonella, Citrobacter and E. coli was studied in vitro using S. typhimurium strain F98. There was complete inhibition of multiplication of S. typhimurium when it was added to stationary-phase broth cultures of different Salmonella serotypes, but only partial inhibition when added to broth cultures of E. coli. The degree of inhibition between different mutants of F98 was affected by the numbers of bacteria of the inhibiting strain, but this was not the only factor, since exponential-phase bacterial cells were less inhibitory than stationary-phase cells. The inhibitory effect was produced at temperatures between 20°C and 40°C. The complete inhibition of growth observed between F98 mutants was abolished by ampicillin, rifampicin and streptomycin, but not by nalidixic acid. Inhibition was also prevented by separating the two cultures by a dialysis membrane. A Tnpho A Insertion mutant of F98 was produced which did not show inhibition in vitro but was still inhibitory in vivo. It is suggested that this complete inhibition of bacterial multiplication between organisms of the same genus, which is greater than that produced between organisms from different genera, is mediated by a cell surface protein.

Potentially malignant epithelial oral lesions: Discrepancies between clinical and histological diagnosis

OBJECTIVE: To evaluate the discrepancy index between the clinical and histological diagnosis and the prevalence of epithelial dysplasia and carcinoma in 45 patients with potentially malignant epithelial oral lesions (PMEL). PATIENTS AND METHODS: We submitted 45 patients with PMEL to clinical examination and obtained a biopsy from each. The results of histological diagnosis were compared to the clinical diagnosis. RESULTS: Clinical diagnosis showed that the most common PMEL was leukoplakia followed by lichen planus and by actinic cheilitis associated with leukoplakia. The most common site was the buccal mucosa. Histological diagnosis revealed that 46.7% of the PMEL were lichen planus. The discrepancy index between clinical and histological diagnosis was 24.4%. The higher discrepancy index occurred among leukoplakias. The prevalence of epithelial dysplasia and carcinoma was 17.8%. CONCLUSIONS: We conclude that all PMEL should be submitted to a microscopic analysis because the discrepancy between clinical and histological diagnosis was present in a quarter of these lesions. Otherwise, the epithelial dysplasia and carcinoma were more frequent in the leukoplakias.

Cigarette smoking and high-risk HPV DNA as predisposing factors for high-grade cervical intraepithelial neoplasia (CIN) in young Brazilian women

Background. This cross-sectional study was designed to evaluate the role of cigarette smoking and high-risk HPV types as risk factors of CIN 2 and 3 in young, sexually active Brazilian women. Materials and method. A series of 100 consecutive women with abnormal Pap smears were recruited, subjected to colposcopy, punch biopsy, and questionnaire for their social, sexual and reproductive factors. Of these, 77 women between 20 and 35 years of age (median 26.5 years) with biopsy-confirmed CIN 1 or CIN 2 and 3, were enrolled in this study. Representative samples from the exocervix and endocervix were obtained for HPV testing with the Hybrid Capture HPV-DNA assay, including the probes for the oncogenic HPV types (16, 18, 31, 33, 35, 45, 51, 52 and 56). Results. The overall rate of CIN 2 and 3 was 23/77 (29.8%). The women with CIN 1, 2 and 3 did not differ from each other with regard to their age, race, schooling, marital status, life-time number of sexual partners, age at first intercourse, use of oral contraceptives, or parity. However, current cigarette smoking was strongly associated with CIN 2 and 3 (p < 0,001), and among smokers, the risk of high-grade CIN increased in parallel with the time of exposure (years of smoking) p = 0.07), HPV-DNA of the oncogenic types was detected in 43 (56%) women, the risk of being HPV DNA-positive was significantly higher in CIN 2 and 3 as compared with CIN 1 (p = 0.037). Importantly, the prevalence of high-risk HPV types was significantly higher in cigarette smokers than in non-smokers (p = 0.046). Conclusions. The results indicate that the severity of CIN lesions was clearly related to two fundamental risk factors: 1) high-risk HPV types, and 2) current cigarette smoking. These two risk factors were closely interrelated in that the high-risk HPV types were significantly more frequent in current smokers than in non-smokers, suggesting the possibility of a synergistic action between these two risk factors in cervical carcinogenesis.

Ultrastructural changes on the epithelial cells of uterine tubes of Wistar rats after chronic ethanol ingestion

The present paper describes the morphological alterations of the epithelial layer of the uterine tubes of rats submitted to experimental chronic alcoholism using anatomical, histological, ultrastructural and morphometric methods. Sixty adult rats (Rattus norvegicus albinus) at the same age (3 months) and with a mean body weight of 228 g were divided into two groups. The control group received solid diet (Purina rat chow) and tap water ad libitum. The alcoholic group received the same solid diet and was allowed to drink only sugar cane brandy dissolved in 30° Gay Lussac (v/v). After periods of 90, 180 and 270 days of treatment animals at normal estrus were anaesthetised with ethyl ether, weighed and sacrificed. Subsequently, the uterine tubes were dissected, weighed and prepared for TEM and SEM methods. The final mean body weights were similar in the control and alcoholic groups. The morphometric analysis showed no difference between control and alcoholic epithelial height. The alcoholic animals showed ultrastructural alterations: intense lipid droplet and lysosomes accumulation, dilated rough endoplasmic reticulum cisternae and vacuolization in both periods of treatment. It was concluded that alcohol acts as a toxin on the epithelial layer of the uterine tubes of rats.

Effects of uracil calculi on cell growth and apoptosis in the BBN- initiated Wistar rat urinary bladder mucosa

The different potential of initiated and non-initiated urinary bladder mucosa (UBM) to develop neoplasia was quantitatively evaluated in the male Wistar rat. Initiation of carcinogenesis was accomplished with N-butyl-N-(4- hydroxybutyl)-nitrosamine (BBN). Stimuli for cell proliferation and apoptosis were obtained by exposure followed by withdrawal of 3% Uracil in the diet. The proliferation index (PI) was estimated in UBM immunostained for the proliferating nuclear cell antigen (PCNA). The apoptotic index (AI) and the density of papillary/nodular hyperplasia (PNH) were estimated in hematoxilin- eosin stained sections. PNH was the main proliferative response to the mechanical irritation by uracil, irrespective of previous initiation with BBN. Uracil exposure induced higher PI and PNH density in the initiated rats. After uracil withdrawal, there was a significant increase of the AI in both uracil-treated groups, which correlated well to the respective PNH density. However, at the end of the experiment, PNH incidence and density were significantly higher in the BBN-initiated mucosa, which also presented 18% incidence of papillomas and 27% of carcinomas. Therefore, under prolonged uracil calculi trauma, the UBM of BBN-initiated Wistar rats gives rise to epithelial proliferative lesions that progress to neoplasia through acquired resistance to apoptosis.

Efeito de drogas utilizadas no tratamento de hipertensão arterial sistêmica sobre a pressão intra-ocular: Estudo experimental no cão

Purpose: To study the effects of two drugs (captopril and propranolol) used in the treatment of systemic hypertension, on the intraocular pressure (IOP) of anesthetized dogs. Methods: 24 dogs, divided into 3 groups of 8 each. In the first group, 1.5 mg/kg IV of captopril (an angiotensin converting enzyme inhibitor) was administered. In the second group, 1.5 mg/kg IV of propranolol (a beta-blocker) was administered. The third group was the control. IOP and blood pressure (BP) were measured by manometry. The perfusion pressure was calculated by the difference between BP and IOP (BP-IOP). The parameters were studied at 6 moments (0, 10, 30, 60, 90 and 120 minutes). Results: There was significant reduction of IOP (p<0.05) with captopril and propranolol, without difference between the drugs. With captopril the BP and PP decreased markedly at 10 and 30 minutes. With propranolol there was no reduction of BP or PP. Conclusions: Captopril and propranolol reduced IOP. However, the marked reduction of BP, and consequently of PP caused by captopril may be undesirable for irrigation of the optic nerve.

Adesão de protozoários ̀a superfície de dispositivos intra-uterinos

Intrauterine devices (IUD) have been used by approximately hundred million of women in the world. IUD are unprescribed to women who have pelvic inflammation disease predisposition which is caused in general by non-treated sexually transmitted diseases (STD). Trichomoniasis, one of the most important vaginal infections, is caused by a flagellated protozoan, Trichomonas vaginalis, transmitted by sexual contact and also asyntomatic women are able to transmit it. The objective of this work was verify by scanning microscopy the adhesion of this protozoan on plastic and metalic IUD surfaces. IUD fragments were added in Diamond medium containing T. vaginalis and after 3 days at 37°C incubation, they were taken out and treated as necessary for scanning microscopy. The analysis showed showed the adhesion of the protozoans on plastic and metalic IUD surfaces. Even though the IUD were not yet directly associated with high incidence of the inflammation pelvic disease, it would become an infection reservoir of potencial pathogenic organisms.

Immunocytochemical study of Ki-67 as a prognostic marker in canine mammary neoplasia

Background: Canine mammary tumors are challenging for clinicians and pathologists because of complex histologic classification, low specificity of cytologic diagnosis, and unpredictable biological behavior. In histologic specimens, expression of tumor proliferation marker Ki-67, a nuclear nonhistone protein, has been shown to have prognostic value for canine mammary tumors and to correlate with malignancy and low survival rates. Objective: The objective of this study was to measure the proliferation index of canine mammary tumors by immunochemical detection of Ki-67 in cytologic specimens and to determine its relationship to clinical and pathologic variables and patient outcome. Methods: Spontaneous mammary tumors from 31 female dogs were surgically excised. Imprint specimens for cytologic evaluation were wet-fixed in ethanol; histologic specimens were prepared routinely. Immunostaining was performed with the PH 177 monoclonal antibody against Ki-67; proliferation index was graded from negative to +++. Dogs were followed for 18 months. Multivariate logistic regression analysis was used to determine correlations between immunocytochemical results, tumor and clinical variables, and patient outcome. Results: Ki-67 proliferation indices in cytologic specimens were significantly lower for nonmalignant tumors than for malignant tumors. High index values of Ki-67 were positively correlated with metastasis, death from neoplasia, low disease-free survival rates, and low overall survival rate. With the exception of 4 specimens for which cellularity was insufficient, positive expression of Ki-67 in cytologic specimens correlated with that of histologic specimens. Conclusions: The prognostic value of the Ki-67 index in canine mammary tumors by using wet-fixed cytology imprint specimens was similar to that observed previously for histologic specimens. Immunocytochemical detection of Ki-67 could improve the accuracy and value of cytology by providing safe and rapid information about malignancy and patient outcome. © 2004 American Society for Veterinary Clinical Pathology.

Intraepithelial alterations in the Guinea pig lateral prostate at different ages after estradiol treatment

The prostate is an accessory gland of the mammal reproductive system with great volume and high functional importance. Many works infer that, in addition to the androgenic ones, the estrogen can be associated with benign prostatic hyperplasia and prostatic cancer, but no conclusive evidence exists on the role of estrogen in normal prostatic and neoplastic tissue. The objective of this work was to evaluate the effects of chronic administration of estradiol benzoate on the lateral prostate of guinea pigs in the pre-pubescent, pubescent, post-pubescent and adult phases, with emphasis on the modifications provoked by this hormone on the glandular epithelium. The analyses of the estradiol-treated and control groups were investigated using histological procedures and transmission electron microscopy. The histopathological analysis of the lateral prostate in the treated group revealed areas where epithelial dysplasia was observed, assuming at some places a pattern of epithelial stratification characteristic of prostatic intraepithelial neoplasia. After ultrastructural analysis, the following were observed: enlargement of the internal membranes, heterogeneity in the cellular types, hypertrophy of the basal cells and apparent decrease of cytoplasmic organelles in some cells of the prostatic intraepithelial neoplasia. Still, a loss of cellular polarity was observed, along with nuclei of various forms, sizes and heights - as well as irregular chromatin distribution patterns. Such alterations were found mainly in pubescent, post-pubescent and adult animals subject to the chronic administration of estradiol. These findings reinforce the already existent data in understanding the role of estrogen in the etiology of prostatic diseases.

Prostatic stromal microenvironment and experimental diabetes

The diabetes causes alterations in various organ systems, including the male accessory sex glands. The prostate is very important in the reproductive process and it is a frequent target of malignant changes. The aim of this work was to demonstrate the histochemical and ultrastructural alterations in the prostate of diabetic animals. Two groups of animals were utilized: control and non-obese diabetic mice (NOD). Twelve days after the characterization of diabetic status the ventral prostate was collected, fixed in Karnovsky and paraformaldehyde, processed for histochemistry and TEM associated to stereology. The results showed reduction of the epithelial area and increasing of the stromal area with muscular and collagen hypertrophy in the prostatic gland. It was characterized the development of prostatic intraepithelial neoplasia, inflammatory processes and dilation of the organelles involved in the secretory process. It was concluded that diabetes besides damaging the reproductive process, affects the glandular homeostasis favoring the development of prostatic pathologies. ©2005, European Journal of Histochemistry.

Experimental model of pulmonary carcinogenesis in Wistar rats

Purpose: To elaborate an experimental model of pulmonary carcinogenesis in Wistar rats. Methods: Male Rattus norvegicus albinus, Wistar lineage was carried through an intra-pulmonary instillation of the Benzo[a]pyrene (B[a]P) dilution in alcohol 70%, a polycyclic aromatic hydrocarbon widely known by its power of tumoral induction. Three experimental groups had been formed with 08 animals each: Control Group (Alcohol 70%); B[a]P Group 10 mg/kg; e B[a]P Group 20mg/ kg, submitted to euthanasia 08, 10, 12 and 14 weeks after the experimental procedure. The pulmonary sections had been colored by hematoxilin-eosin (HE) and submitted to the morphometrical analysis to describe the tissue alterations. Results: The presence of diffuse inflammatory alterations was observed in all groups, however, at the analysis of the pulmonary tissue of the experimental groups, it had been observed hyperplasic alterations (BALT hyperplasia), and in one of the animals of the experimental group 20mg/kg (12 weeks), it was noticed the presence of cellular epithelial tracheal pleomorphism, suggesting the adenocarcinoma formation in situ. Conclusion: The main secondary alterations to the intra-pulmonary instillation of B[a]P in Wistar rats were: cellular proliferation, inflammatory alterations of several degrees and nodular lymphoid hyperplasias. The association of an activator agent of the pulmonary metabolic reply is necessary to establish the ideal reply-dose to the development of the lung cancer.