Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats.

Trypanosoma cruzi (T cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair, Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n = 20). All the animals were anesthetized, at to the first lower right molar was extracted. The EG animals were inoculated subcutaneously at to with 0.1 mL of 10 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume ofsaline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed informalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

Histologic and histomorphometric study of bone repair under acute Trypanosoma cruzi infection in rats

Trypanosoma cruzi (T. cruzi) is an intracellular protozoan pathogen that causes American trypanosomiasis (Chagas disease). The aim of this study was to evaluate the histopathological effects of acute infection by T. cruzi on bone repair. Wistar rats were used throughout. The animals were assigned to two groups: Control Group (CG n =20) and Experimental Group (EG n =20). All the animals were anesthetized, at t0 the first lower right molar was extracted. The EG animals were inoculated subcutaneously at t0 with 0.1 mL of 105 trypomastigotes of the virulent strain Tulahuen of T. cruzi. The CG animals were administered an equivalent volume of saline solution subcutaneously. The animals in both groups were euthanized at 15 days post-infection and tooth extraction. The mandibles were resected, fixed in formalin solution, radiographed, decalcified and embedded in paraffin. Bucco-lingually oriented sections were obtained at the level of the mesial tooth socket of the first lower molar, and stained with hematoxylin-eosin. Total alveolar volume (TV) and bone volume (TBV/TV) in the apical third of the tooth socket were evaluated histomorphometrically. The histological analysis revealed an alteration in post-extraction bone tissue repair in animals infected by T. cruzi. A reduction in osteogenic activity was observed concomitant with a rise in quiescent and eroded bone surfaces. Histomorphometric evaluation revealed a significant reduction (19%) in total alveolar volume (TV) and bone volume (TBV/TV) (24%) in the apical third of the tooth socket in animals infected with T. cruzi in comparison to non-infected animals (p<0.05). The results obtained using this experimental model showed decreased osteogenesis in bone tissue repair under acute Trypanosoma cruzi infection in rats.

El Trypanosoma cruzi (T. cruzi) es un protozoario intracelular que causa Trypanosomoniasis Americana (Enfermedad de Chagas). El objetivo del presente trabajo fue el estudio histopatologico del efecto de la infeccion aguda por Trypanosoma cruzi sobre la reparacion del tejido oseo. Se utilizaron ratas Wistar macho que fueron asignadas a dos grupos: Grupo Control (GC n =20) y Grupo Experimental (GE n =20). Los animales de ambos grupos, bajo anestesia general intraperitoneal, fueron sometidos a t0, a exodoncia del primer molar inferior derecho, en el GE fueron inoculados,a t0 por via subcutanea en la region inguinal izquierda con 0.1 mL de 105 tripomastigotes de la cepa virulenta Tulahuen de Trypanosoma cruzi. A los animales del GC se les administro el volumen equivalente de solucion salina por via subcutanea. A los animales de ambos grupos se les practico la eutanasia a los 15 dias. Se resecaron las mandibulas, se fijaron en solucion de formol al 10%, se radiografiaron, se descalcificaron y se incluyeron en parafina. Se obtuvieron cortes orientados en sentido vestibulo-lingual a nivel del alveolo mesial del primer molar inferior derecho y se colorearon con hematoxilina-eosina para su posterior estudio histologico e histomorfometrico. Histologicamente se observo una menor actividad osteogenica a expensas de un incremento de las superficies quiescentes y de las superficies erosivas en el GE. En la evaluacion histomorfometrica se detecto disminucion estadiasticamente significativa del volumen oseo total (19%) y del volumen trabecular en el tercio apical del alveolo (24%) en el GE con respecto al GC (p<0.05). Los resultados obtenidos en este modelo experimental evidencian una disminucion de la osteogenesis en la reparacion osea en ratas con infeccion aguda por Trypanosoma cruzi.

Nucleolar organizer regions (AgNOR) and subepithelial vascularization as field cancerization markers in oral mucosa biopsies of alcoholic and smoking patients.

OBJECTIVE: The aim of this study was to show that variations in nucleolar organizer regions (AgNOR) and the increase in subepithelial vascularization could reveal changes related to markers of field cancerization in alcoholic and smoking patients who have not yet expressed clinical or histological malignant lesions. STUDY DESIGN: Quantitative variations in epithelial AgNOR and in the vascularization of the underlying connective tissue were assessed by image analysis in histologically normal biopsy specimens from alcohol drinkers and smoking patients (DS). AgNORs were evidenced by silver staining and vessel walls were labeled by immunohistochemical demonstration of the CD34 antigen. Samples of oral mucosa of nonalcoholic, nonsmoking patients (NDS) obtained during surgical procedures served as controls. Eight parameters related to number, volume, and shape of nuclei and AgNORs, and 4 parameters related to number and diameter of vascular sections were evaluated. Differences between DS and NDS groups were statistically evaluated by means of ANOVA test and posterior Bonferroni comparisons. RESULTS: The morphometric analysis revealed more irregular-shaped AgNORs in the superficial and suprabasal layers of the oral mucosa of DS patients. The suprabasal layers also exhibited a significantly larger number of AgNORs. The normal oral mucosa of DS patients exhibited a greater vascular density, with predominance of small-caliber blood vessels underlying the basement membrane. CONCLUSION: The variations in AgNOR and epithelial vascularization would be practical biomarkers to evaluate changes underlying the augmented risk of cancerization in oral mucosa.

Dental research productivity in Argentina (1993 to 2003).

The scientific presentations at the annual meetings of the Argentine Division of the I.A.D.R. (S.A.I.O.) are proof of the scientific production of this country in dental research. Our annual meetings provide a forum for the rapid communication and discussion of research. However, only peer-reviewed articles, published in journals indexed in worldwide-accepted databases such as MEDLINE are permanent records of the research work and can reach out to a global audience. A useful indicator of quality and publication efficiency of research work is the rate of publication (RP), i.e. relationship between the quantity of presentations and subsequent publications in peer-reviewed journals. Previous works analyzed the two periods: 1980-1989 and 1990-1995 (Acta Odont. Latinoamer 7(2):39-46,1993 and Acta Odont. Latinoamer. 10(1):63-69, 1997). The aim of this work was to update the informatiod and study the publication rate of national Dental research works. The 1669 works produced by national research centers presented at the Annual Meetings of the S.A.LO. from 1993 to 2003 were evaluated. Employing the authors' index of the programs of the Annual Meetings of the S.A.I.O. we searched for possible publications in MEDLINE. The references obtained were compared with the presentations (title and authors) disregarding those that had not been communicated previously at our Division meeting. Presentations and the corresponding publications were grouped according to research center and within each center according to subject area. The following parameters were obtained: PR, time between Presentation and publication and language of publication. PR increased in 1993-2003 (1/4.8, 20.79%) when compared to the periods studied previously (1/8, 12%). Most of the publications were in English and had been published within 4 years after presentation. The increase in the number of S.A.I.O. presentations published in peer-reviewed journals shows an improvement in terms of research productivity in dental research in Argentina.