Injerto de matriz ósea en partículas asociado a plasma rico en plaquetas (PRP): estudio experimental / Bone matrix and platelet rich plasma (PRP) grafting: an experimental study

Los injertos o sustitutos óseos se utilizan con el fin de solucionar situaciones de déficit en el hueso, aunque aún existen controversias sobre los mecanismos de osteoinducción que estos rellenos promueven dentro de los tejidos. La combinación con plasma rico en plaquetas (PRP) podría aumentar la capacidad de reparación ósea. Objetivo: estudiar el efecto biológico (biocompatibilidad y osteoinducción) de la matriz ósea de la Universidad Nacional de Córdoba (MO-UNC) y el plasma rico en plaquetas (PRP). Métodos: se utilizaron 30 ratas Wistar anestesiadas con ketamina-xilazina. En 4 sitios del tejido celular subcutáneo de la región dorsal se implantaron tubos de silicona conteniendo los materiales experimentales: MO (partículas de MO-UNC), PRP, MO+PRP (partículas de MO embebidas en PRP), GC (Controles, sin relleno). Se tomaron biopsias de los sitios de implante a los 30 y 60 días poscirugía y se obtuvieron cortes histológicos para analizar la biocompatibilidad y la neoformación ósea alrededor de los materiales implantados. Resultados: si bien en ninguno de los grupos se identificó tejido óseo neoformado, en el grupo MO+PRP a 30 días se constató un aumento del número de cpailares neoformados alrededor de las partículas. A los 60 días, las partículas de MO-UNC mostraron áreas lacunares compatibles con actividad resorsiva. En este estudio, las partículas de MO-UNC se comportaron como injertos biocompatibles, siendo progresivamente resorbidas en el organismo de los animales. Se confirmó un efecto angiogénico del PRP...

Particulate bone matrix usage for alveolar bone conservation. A histomorphometric study.

UNLABELLED: Different filling materials have been used in an attempt to repair bone loss situations. OBJECTIVE: The present study aimed to examine the effect of a bone matrix in post - extraction remodelling of the alveolar bone, and to perform a histomorphometric analysis of the residual alveolar ridges in Wistar rats. MATERIAL AND METHODS: Both rat first lower molars were extracted and the right alveoli were filled with particles of a bone matrix with mineral components (MO - UNC) (experimental group, EG). The left alveoli were used as a control group (CG). The animals were sacrificed at 0 hr., 15, 30 and 60 days after extraction, and the samples were processed. Histological sections were made at the level of the mesial alveolus of the first lower molar. Repair of the alveoli was histologically evaluated and a histomorphometric study of total alveolar volume (TAV), height of the buccal plate (Bh), height of the lingual plate (Lh) and percentage of osseointegration (OI) of the particles was performed to compare the residual ridges of CG with those of the EG. Statistical analysis of the data was performed. RESULTS: In the cases of the experimental group, newly - formed bone tissue was identified around the MO - UNC particles (osseointegration). Histomorphometric data indicate that, at 60 days post - extraction, TAV was significantly greater for EG when compared with CG (p <0.05) and the percentage of osseointegration of the particles increased as a function of time (57.6 %, 90.5% y 95.5%, for EG at 15, 30 y 60 days respectively). CONCLUSIONS: The bone matrix (MO - UNC) evaluated in this study is an osteoconductive material that prevents the collapse of post - extraction alveolar bone.

Particulate bone matrix usage for alveolar bone conservation. A histomorphometric study / Particulate bone matrix usage for alveolar bone conservation. A histomorphometric study.

UNLABELLED: Different filling materials have been used in an attempt to repair bone loss situations. OBJECTIVE: The present study aimed to examine the effect of a bone matrix in post - extraction remodelling of the alveolar bone, and to perform a histomorphometric analysis of the residual alveolar ridges in Wistar rats. MATERIAL AND METHODS: Both rat first lower molars were extracted and the right alveoli were filled with particles of a bone matrix with mineral components (MO - UNC) (experimental group, EG). The left alveoli were used as a control group (CG). The animals were sacrificed at 0 hr., 15, 30 and 60 days after extraction, and the samples were processed. Histological sections were made at the level of the mesial alveolus of the first lower molar. Repair of the alveoli was histologically evaluated and a histomorphometric study of total alveolar volume (TAV), height of the buccal plate (Bh), height of the lingual plate (Lh) and percentage of osseointegration (OI) of the particles was performed to compare the residual ridges of CG with those of the EG. Statistical analysis of the data was performed. RESULTS: In the cases of the experimental group, newly - formed bone tissue was identified around the MO - UNC particles (osseointegration). Histomorphometric data indicate that, at 60 days post - extraction, TAV was significantly greater for EG when compared with CG (p <0.05) and the percentage of osseointegration of the particles increased as a function of time (57.6

, for EG at 15, 30 y 60 days respectively). CONCLUSIONS: The bone matrix (MO - UNC) evaluated in this study is an osteoconductive material that prevents the collapse of post - extraction alveolar bone.

Particulate bone matrix usage for alveolar bone conservation. A histomorphometric study. / Particulate bone matrix usage for alveolar bone conservation. A histomorphometric study.

UNLABELLED: Different filling materials have been used in an attempt to repair bone loss situations. OBJECTIVE: The present study aimed to examine the effect of a bone matrix in post - extraction remodelling of the alveolar bone, and to perform a histomorphometric analysis of the residual alveolar ridges in Wistar rats. MATERIAL AND METHODS: Both rat first lower molars were extracted and the right alveoli were filled with particles of a bone matrix with mineral components (MO - UNC) (experimental group, EG). The left alveoli were used as a control group (CG). The animals were sacrificed at 0 hr., 15, 30 and 60 days after extraction, and the samples were processed. Histological sections were made at the level of the mesial alveolus of the first lower molar. Repair of the alveoli was histologically evaluated and a histomorphometric study of total alveolar volume (TAV), height of the buccal plate (Bh), height of the lingual plate (Lh) and percentage of osseointegration (OI) of the particles was performed to compare the residual ridges of CG with those of the EG. Statistical analysis of the data was performed. RESULTS: In the cases of the experimental group, newly - formed bone tissue was identified around the MO - UNC particles (osseointegration). Histomorphometric data indicate that, at 60 days post - extraction, TAV was significantly greater for EG when compared with CG (p <0.05) and the percentage of osseointegration of the particles increased as a function of time (57.6

, 90.5

y 95.5

, for EG at 15, 30 y 60 days respectively). CONCLUSIONS: The bone matrix (MO - UNC) evaluated in this study is an osteoconductive material that prevents the collapse of post - extraction alveolar bone.

Estudio citomorfométrico de pacientes con cáncer y desórdenes potencialmente malignos de la cavidad bucal / Citomorphometric study of patients with cancer and potentially malignant disorders of the oral cavity

La detección temprana de lesiones bucales promete aumentar sobrevivencia y reducir la morbilidad de los pacientes que sufren esta condición. Un método alternativo para el examen de lesiones en la cavidad bucal, es la citología. Objetivo: valorar las relaciones del tamaño núcleo/citoplasma de células de mucosa bucal sana, de lesiones bucales potencialmente malignas y de cáncer bucal, obtenidas con citología exfoliativa utilizando citomorfometría. Material y método: Se realizó citología a 22 pacientes, de ambos sexos, con edades entre 23 y 81 años utilizando cytobrush. Las muestras se dividieron en tres grupos: 1) citologías de pacientes con lesiones de cáncer bucal (n=7); 2) citologías de pacientes con desórdenes bucales potencialmente malignos (leucoplasia y líquen) (n=15); 3) citologías del lado sano de pacientes con lesiones de cáncer y desórdenes bucales potencialmente malignos (grupo control) (n=15). Se seleccionaron 30 células de cada paciente y se midió el área nuclear (AN), la citoplasmática (AC) y se calculó la relación AN/AN. Se utilizó el Test de Kruskal Wallis y el Sofware estadístico Infostat. Resultados: No se encontraron diferencias significativas entre los tres grupos estudiados al valorar la relación AN/AC. Teniendo en cuenta el género, se observó que en las mujeres se diferenciaron significativamente las células del grupo control de las de los grupos de lesiones. En el género masculino se observaron diferencias significativas entre los tres grupos celulares. No hubo diferencias significativas entre los diferentes grupos etarios .Discusión: A pesar de las diferencias significativas entre los géneros, no es posible hacer una buena separación de los tres grupos de estudio, utilizando solamente citología exfoliativa.

Early detection of bucal lesions promises to increase survival and to reduce morbidity in patients suffering from this condition. An alternative method for examining lesions in the bucal cavity is cytology. Objective: To assess by cytomorphometry the relationship of size nucleus / cytoplasm of superficial cells from healthy bucal mucosa, from potentially malignant bucal disordes lesions and bucal cancer using exfoliative cytology. Material and methods: PAP smear was performed in 22 patients of both gender, aged between 23 and 81. Cytobrush was used. The samples were divided into three study groups: 1) smears of patients with bucal cancer lesions (n = 7), 2) smears of patients with potentially malignant bucal disordes lesions (n = 15), lesions considered were leukoplakia and lichens ; 3) (control group) (n=15): smears of the healthy side of patients with cancer and potentially malignant bucal disordes lesions.Thirty cells were selected for each patient and the nuclear area (NA), cytoplasmic area (CA) were measured and the ratio NA / CA was calculated. We used Kruskal Wallis and Statistical Software InfoStat. Results: No significant differences were found between the three groups studied the relationship NA / CA was assesed . When comparing cells from each of the three groups considering the gender of the patients separately, we found that in women differ significantly from the control group cells and groups of injuries, we could not discriminate between cells obtained from potentially malignant bucal disordes lesions and cancer lesions . In the male gender differences were significant among the three cell groups. Discusion: Despite the significant gender differences, we could not difference the three study groups using only exfoliative cytology.

Graph models for phenotype and genotype association between oral mucosa and submandibular gland tumorigenesis in rat.

BACKGROUND: In recent years, success of statistics in field of genetics has been the identification of genes that affect the process of disease. Experimental models using animals enable early stages of tumor development to be studied. The aim of this study was to apply graph models to assess the association between the observed phenotypic changes in rat oral mucosa and induced tumorigenesis in the submandibular gland (SMG). MATERIALS AND METHODS: We studied changes in oncogenes TP53 and bcl-2, histopathological and immunomarker variables in samples of oral mucosa and SMG of Wistar male rats, 60 days old and 180 g in weight, in which tumorigenesis was induced in their SMG by a 0.5% solution of 9,10-dimethyl-1,2-benzanthracene in acetone. A set of linear structural equations were defined, with each formula indicating the response variables and the direct influences. In graph models, saliva was considered as a latent variable. The association was analyzed using Graphical Gaussian Markov models and odd ratios. RESULTS: About 40% of animals treated with 9, 10-dimethyl-1, 2-benzanthracene showed histological alterations in the epithelial basal strata of their oral mucosa only at 150 days. Statistical models indicated a relationship between gene alteration in gene bcl-2 in the SMG and histological changes observed in the oral mucosa (P = 0.04). CONCLUSION: Graph statistical model with one latent variable allows to conclude that these results associated with other clinical parameters may be useful in detecting early changes in SMG tumorigenesis. Furthermore, the design of randomized sampling of oral mucosa allows to validate these results and establish a reliable methodology for presumptive diagnosis or screening in the future.

Early phenotypic and genotypic alterations in submandibular gland oncogenesis in rats.

The present study evaluates the phenotypic and genotypic changes that take place during early oncogenesis. The submandibular glands of male rats were injected with a 0.5% solution of 9,10-dimethyl-1,2-benzanthracene (DMBA) in acetone. Gland samples were taken at 0, 7, 30 and 150 days post-injection and submitted to histological, biochemical, immunocytochemical and PCR evaluation. Histopathological analysis was performed on hematoxylin-eosin stained slides. Total protein content was assessed by Lowry's method and the protein profile was analyzed by 12% SDS-PAGE. Bcl-2 was demonstrated by silver-enhanced gold immunolabeling. p53 immunolabeling was performed using the streptavidin-biotin system. All the treated animals developed carcinoma-like lesions at 30 and 150 days. Total protein concentration rose significantly (p < 0.05) above control values at 7, 30 and 150 days. The treated glands exhibited positive immunolabeling for p53 in the nuclei of neoplastic cells at 30 and 150 days. Treated glands also showed positive cytoplasmic immunolabeling for Bcl-2, exhibiting statistically significant differences between 7, 30 and 150 days (p = 0.0015), and with controls (p < 0.0001). No p53 mutations were observed whereas a point mutation, C-to-A, of the Bcl-2 gene was detected at 7, 30 and 150 days by PCR amplification. This mutation led to a single aminoacid change (thre --> asn) in the protein molecule. Our results suggest that the early histopathological changes correspond to quantitative and qualitative protein changes. The histopathological, biochemical, immunocytochemical and genetic alterations observed during the course of experimental carcinogenesis in the submandibular gland of the rat could constitute reproducible indices of malignant transformation applicable to human oncogenesis, given the high degree of homology between the oncogenes of mice, rats and human beings.

Early phenotypic and genotypic alterations in submandibular gland oncogenesis in rats

Se evaluaron modificaciones del fenotipo y genotipo en glándulas submandibulares durante el desarrollo temprano de la tumorogénesis. Glándulas submandibulares de ratas macho fueron inyectadas con una solución de 0.5 por ciento de 9,10 dimetil 1,2-benzathracene (DMBA) diluida en acetona. Muestras de glándulas fueron analizadas mediante técnicas histológicas, bioquímicas, inmunocitoquímicas y por PCR a los 0, 7, 30 y 150 días postinyección. Para los estudios histopatológicos se utilizó la técnica de hematoxilina-eosina. Se determinó la concentración de proteínas totales por el método de Lowry y se realizaron corridas electroforéticas en gel de poliacrilamida SDS-PAGE al 12 por ciento para determinar el perfil proteico. Se realizó inmunomarcación para Bcl-2 con oro coloidal-plata y para p53 por streptavidina-biotina. Todos los animales tratados desarrollaron cambios similares a carcinomas a los 30 y 150 días. La concentracióan de proteínas totales aumentó significativamente (p<0,05) a los 7, 30 y 150 días en relación a los controles. En glándulas inducidas la inmunomarcación fue positiva para la proteína p53 en núcleos de células neoplásicas a los 30 y 150 días. En las mismas glándulas, la marcación citoplasmática de Bcl-2 fue positiva a los 7, 30 y 150 días(p=0,0015) y en relación a los controles (p<0,0001). No se observaron mutaciones de p53, mientras que se observó una mutación puntual, C A del gen bcl-2 a los 7, 30 y 150 días que generó un cambio de aminoácidos en la proteína (thre asn). Nuestros resultados sugieren que los cambios histopatológicos tempranos corresponden a modificaciones cuantitativas y cualitativas de las proteínas. Las modificaciones observadas a nivel histopatológico, bioquímico, inmunocitoquímico y genético en la carcinomgénesis experimental de glándula submandibular de rata podrían representar parámetros reproducibles de transformaciones malignas transferibles al ser humano, dada la alta homología de estos oncogenes entre rata, ratones...

Early phenotypic and genotypic alterations in submandibular gland oncogenesis in rats

Se evaluaron modificaciones del fenotipo y genotipo en glándulas submandibulares durante el desarrollo temprano de la tumorogénesis. Glándulas submandibulares de ratas macho fueron inyectadas con una solución de 0.5 por ciento de 9,10 dimetil 1,2-benzathracene (DMBA) diluida en acetona. Muestras de glándulas fueron analizadas mediante técnicas histológicas, bioquímicas, inmunocitoquímicas y por PCR a los 0, 7, 30 y 150 días postinyección. Para los estudios histopatológicos se utilizó la técnica de hematoxilina-eosina. Se determinó la concentración de proteínas totales por el método de Lowry y se realizaron corridas electroforéticas en gel de poliacrilamida SDS-PAGE al 12 por ciento para determinar el perfil proteico. Se realizó inmunomarcación para Bcl-2 con oro coloidal-plata y para p53 por streptavidina-biotina. Todos los animales tratados desarrollaron cambios similares a carcinomas a los 30 y 150 días. La concentracióan de proteínas totales aumentó significativamente (p<0,05) a los 7, 30 y 150 días en relación a los controles. En glándulas inducidas la inmunomarcación fue positiva para la proteína p53 en núcleos de células neoplásicas a los 30 y 150 días. En las mismas glándulas, la marcación citoplasmática de Bcl-2 fue positiva a los 7, 30 y 150 días(p=0,0015) y en relación a los controles (p<0,0001). No se observaron mutaciones de p53, mientras que se observó una mutación puntual, C A del gen bcl-2 a los 7, 30 y 150 días que generó un cambio de aminoácidos en la proteína (thre asn). Nuestros resultados sugieren que los cambios histopatológicos tempranos corresponden a modificaciones cuantitativas y cualitativas de las proteínas. Las modificaciones observadas a nivel histopatológico, bioquímico, inmunocitoquímico y genético en la carcinomgénesis experimental de glándula submandibular de rata podrían representar parámetros reproducibles de transformaciones malignas transferibles al ser humano, dada la alta homología de estos oncogenes entre rata, ratones...(AU)

Early phenotypic and genotypic alterations in submandibular gland oncogenesis in rats

Se evaluaron modificaciones del fenotipo y genotipo en glándulas submandibulares durante el desarrollo temprano de la tumorogénesis. Glándulas submandibulares de ratas macho fueron inyectadas con una solución de 0.5 por ciento de 9,10 dimetil 1,2-benzathracene (DMBA) diluida en acetona. Muestras de glándulas fueron analizadas mediante técnicas histológicas, bioquímicas, inmunocitoquímicas y por PCR a los 0, 7, 30 y 150 días postinyección. Para los estudios histopatológicos se utilizó la técnica de hematoxilina-eosina. Se determinó la concentración de proteínas totales por el método de Lowry y se realizaron corridas electroforéticas en gel de poliacrilamida SDS-PAGE al 12 por ciento para determinar el perfil proteico. Se realizó inmunomarcación para Bcl-2 con oro coloidal-plata y para p53 por streptavidina-biotina. Todos los animales tratados desarrollaron cambios similares a carcinomas a los 30 y 150 días. La concentracióan de proteínas totales aumentó significativamente (p<0,05) a los 7, 30 y 150 días en relación a los controles. En glándulas inducidas la inmunomarcación fue positiva para la proteína p53 en núcleos de células neoplásicas a los 30 y 150 días. En las mismas glándulas, la marcación citoplasmática de Bcl-2 fue positiva a los 7, 30 y 150 días(p=0,0015) y en relación a los controles (p<0,0001). No se observaron mutaciones de p53, mientras que se observó una mutación puntual, C A del gen bcl-2 a los 7, 30 y 150 días que generó un cambio de aminoácidos en la proteína (thre asn). Nuestros resultados sugieren que los cambios histopatológicos tempranos corresponden a modificaciones cuantitativas y cualitativas de las proteínas. Las modificaciones observadas a nivel histopatológico, bioquímico, inmunocitoquímico y genético en la carcinomgénesis experimental de glándula submandibular de rata podrían representar parámetros reproducibles de transformaciones malignas transferibles al ser humano, dada la alta homología de estos oncogenes entre rata, ratones...(AU)

Oral health and salivary factors in rural schoolchildren.

The aim of the present study was to assess the association between some salivary factors and the oral health status of rural schoolchildren of Córdoba (Argentina). The study involved 19 students (aged 5-14 years) who attended 8 rural schools of the region. We determined indices (r)dmf-t, (r)DMF-T and S-OHI. pH, salivary flow (vol/min), protein concentration, calcium and phosphate levels and the molar Ca/P ratio were evaluated in stimulated saliva. The arithmetic mean and standard error were assessed for each of the parameters. We employed the Principal Component Analysis (PCA) to assess the similarities and differences between salivary components for the splits (r)dmft = 0, (r)dmft > 0, (r)DMFT = 0 and (r)DMFT > 0. We observed a positive correlation (Spearman's coefficient, p < or = 0.05) between the concentration of proteins, calcium, phosphate and salivary flow. The mean values for the salivary parameters evaluated evidence differences in the oral health status between the different schools under study. In five of the schools evaluated, the variables that best explain the condition of caries disease were concentration of proteins, calcium, phosphate, and the Ca/P molar ratio. The variation observed in the oral health indicators, volume/minute and salivary components between schools evidences the need to perform individual studies for each school and consider the needs and possibilities of each community when designing programs to promote oral health.

Oral health and salivary factors in rural schoolchildren

El propósito del presente trabajo fue evaluar la asociación entre algunos factores salivales y el estado de salud bucodental de escolares rurales de Córdoba (Argentina). El estudio incluyó 199 alumnos entre 5 y 14 años de edad, asistentes a 8 escuelas de la región, determinándose los índice ceo-d(r) y CPO-D(r) y el índice IHO-S. En saliva estimulada se evaluó: pH, flujo salival (vol/min), concentración de proteínas, de calcio y de fosfato y la relación molar Ca/P. Para cada una de las variables se determinó media aritmética y error estándar. Se aplicó el análisis de componente principal (ACP) para explorar las similitudes y diferencias entre los componentes salivales para las categorías ceo-d(r) = 0, ceo-c(r) > 0, CPO-D(r) = 0 y CPO-D(r)>0. Se obsevó correlación positiva (coeficiente de Spearman, p>- 0.05) entre las concentraciones de proteínas, calcio, fosfato y flujo salival. Los valores medios de las variables salivales estudiadas muestran diferencias entre las distintas comunidades escolares, relacionadas con el estado de salud dental de las mismas. En cinco de las ocho excuelas investigadas las variables que mejor explican la condición de enfermedad de caries son concentración de proteínas, calcio, fosfato yla retención molar Ca/P. La variabilidad observada en los indicadores de salud dental, en el volúmen/minuto y en los componentes salivales entre escuelas, evidencia la necesidad de realizar análisis individualizados para cada escuela al momento de diseñar programas de promoción de salud bucal, que respeten las necesidades y posibilidades de cada comunidad.

Oral health and salivary factors in rural schoolchildren

El propósito del presente trabajo fue evaluar la asociación entre algunos factores salivales y el estado de salud bucodental de escolares rurales de Córdoba (Argentina). El estudio incluyó 199 alumnos entre 5 y 14 años de edad, asistentes a 8 escuelas de la región, determinándose los índice ceo-d(r) y CPO-D(r) y el índice IHO-S. En saliva estimulada se evaluó: pH, flujo salival (vol/min), concentración de proteínas, de calcio y de fosfato y la relación molar Ca/P. Para cada una de las variables se determinó media aritmética y error estándar. Se aplicó el análisis de componente principal (ACP) para explorar las similitudes y diferencias entre los componentes salivales para las categorías ceo-d(r) = 0, ceo-c(r) > 0, CPO-D(r) = 0 y CPO-D(r)>0. Se obsevó correlación positiva (coeficiente de Spearman, p>- 0.05) entre las concentraciones de proteínas, calcio, fosfato y flujo salival. Los valores medios de las variables salivales estudiadas muestran diferencias entre las distintas comunidades escolares, relacionadas con el estado de salud dental de las mismas. En cinco de las ocho excuelas investigadas las variables que mejor explican la condición de enfermedad de caries son concentración de proteínas, calcio, fosfato yla retención molar Ca/P. La variabilidad observada en los indicadores de salud dental, en el volúmen/minuto y en los componentes salivales entre escuelas, evidencia la necesidad de realizar análisis individualizados para cada escuela al momento de diseñar programas de promoción de salud bucal, que respeten las necesidades y posibilidades de cada comunidad. (AU)

Oral health and salivary factors in rural schoolchildren.

The aim of the present study was to assess the association between some salivary factors and the oral health status of rural schoolchildren of Córdoba (Argentina). The study involved 19 students (aged 5-14 years) who attended 8 rural schools of the region. We determined indices (r)dmf-t, (r)DMF-T and S-OHI. pH, salivary flow (vol/min), protein concentration, calcium and phosphate levels and the molar Ca/P ratio were evaluated in stimulated saliva. The arithmetic mean and standard error were assessed for each of the parameters. We employed the Principal Component Analysis (PCA) to assess the similarities and differences between salivary components for the splits (r)dmft = 0, (r)dmft > 0, (r)DMFT = 0 and (r)DMFT > 0. We observed a positive correlation (Spearmans coefficient, p < or = 0.05) between the concentration of proteins, calcium, phosphate and salivary flow. The mean values for the salivary parameters evaluated evidence differences in the oral health status between the different schools under study. In five of the schools evaluated, the variables that best explain the condition of caries disease were concentration of proteins, calcium, phosphate, and the Ca/P molar ratio. The variation observed in the oral health indicators, volume/minute and salivary components between schools evidences the need to perform individual studies for each school and consider the needs and possibilities of each community when designing programs to promote oral health.

Effect of low-power radiation (helium/neon) upon submandibulary glands.

OBJECTIVE: The aim of this work was to study the effect of low-power laser radiation on guinea pig salivary glands. BACKGROUND DATA: Low-power laser radiation changes some cellular functions. The effect on salivary glands has not been sufficiently studied. MATERIALS AND METHODS: One hundred and forty-four male guinea pigs (150 +/- 30 g body weight) were used. The animals were divided into two groups: control group (fed animals and those undergoing 2, 4, 8, 10, and 12 h of fasting) and experimental group (irradiated). Both the right and left submandibular glands were later irradiated with helium-neon laser at 7-mW power, with a 0.75-mm spot, under continuous pulse for 2 min in a one-session exposure; a 11.2 J/cm(2) energy density was applied. Then, the irradiated animals were fed, or underwent 2, 4, 8, 10 and 12 h of fasting. Samples of submandibular glands were taken with a punch (5 mm diameter) and were used for optic and transmission electron microscopy studies. RESULTS: The structural observations showed that the irradiation effect was progressive; and showed a trophic stimulant effect at 2 h following irradiation, with vasodilatation, vascular congestion, perivascular infiltrate, and a necrotic picture of glandular parenchyma at longer times. The ultrastructural observations showed alterations of rough endoplasmic reticulum. CONCLUSION: We propose that low-power laser radiation with the doses applied in this study disturbs protein synthesis and secretion of guinea pig submandibulary glands.

Effects induced by isoproterenol during synthesis and secretion of the parotid gland: experimental structural studies

The effect of isoproterenol, a â-adrenergic agonist, on the parotid gland of guinea pig was studied in vivo. Male guinea pigs were fasted 12 h, and then injected intraperitoneally with isoproterenol (30 mg/kg). The parotid glands were processed for light and transmission electron microscopy using conventional techniques. Morphological analysis showed massive granular secretion 2 h after isoproterenol injection and an enlarged apical surface of the plasma membrane, as indicated by the presence of microvilli. Twenty-four hours after injection of isoproterenol the gland had still not returned to its pre-stimulation state. The effect of isoproterenol decreased with time and the apical surface of the plasma membrane eventually resumed its normal (basal) appearance. These data showed that the maximum secretagogue effect of isoproterenol on parotid gland of guinea pig was evident 2 h after injection and decreased according to the time.