Alteraciones morfo-cardiovasculares producidas por bacterias periodontopatógenas en modelo murino / Morphological and cardiovascular alterations produced by periodontopathic bacteria in a murine model

Diferentes autores han descrito a la enfermedad periodontal como un factor de riesgo de ateroesclerosis. Este estudio tuvo como objetivo determinar la posible relación entre las bacterias periodontopatógenas y alteraciones cardiovasculares en modelos murinos con ingesta hiperlipídica. Se utilizaron 30 ratas Wistar divididas en un grupo control (n=5) y tres grupos experimentales (n=15): Grupo I (n=5): dieta normal e infectados; Grupo II (n=5): dieta hiperlipídica y sin infectar y Grupo III (n=5): dieta hiperlipídica e infectados. La infección del surco gingival se logró previa sedación a través de hilos de sutura contaminados, colocados durante 6 días consecutivos, con Pophyromonas gingivalis (P. gingivalis) (5x10a-4 UFC) y Agregatibacter actinomycetemcomitans (A. actinomycetemcomitans) (5x10-4 UFC) obtnidas de muestras de pacientes con periodontitis crónica. A los 30 días posinfección se fijaron muestras de corazón y arteria aorta para su procesamiento. En el grupo control no se encontraron alteraciones. En el grupo I se observó en el endocardio valvular abundante exudado fibrinoleucocitario y focos hemorrágicos. En el miocardio, neovascularización y sufusiones hemorrágicos y en la pared de vasos arteriales, engrosamiento intimal. En el grupo II se observaron depósitos lipídicos en el interior de las células endoteliales, estrías grasas y pequeños ateromas. El grupo III mostró en un 100 por ciento de los casos, placas ateromatosas bien detalladas con abundante depósito de colesterol, calcificaciones, hemorragias y neovascularización. La suma de estos factores de riesgo: dieta hiperlipídica e infección con bacterias periodontopatógenas, potenciarían la expresión de alteraciones cardíacas y coronarias, incrementando la formación de ateromas

Alteraciones morfo-cardiovasculares producidas por bacterias periodontopatógenas en modelo murino / Morphological and cardiovascular alterations produced by periodontopathic bacteria in a murine model

Diferentes autores han descrito a la enfermedad periodontal como un factor de riesgo de ateroesclerosis. Este estudio tuvo como objetivo determinar la posible relación entre las bacterias periodontopatógenas y alteraciones cardiovasculares en modelos murinos con ingesta hiperlipídica. Se utilizaron 30 ratas Wistar divididas en un grupo control (n=5) y tres grupos experimentales (n=15): Grupo I (n=5): dieta normal e infectados; Grupo II (n=5): dieta hiperlipídica y sin infectar y Grupo III (n=5): dieta hiperlipídica e infectados. La infección del surco gingival se logró previa sedación a través de hilos de sutura contaminados, colocados durante 6 días consecutivos, con Pophyromonas gingivalis (P. gingivalis) (5x10a-4 UFC) y Agregatibacter actinomycetemcomitans (A. actinomycetemcomitans) (5x10-4 UFC) obtnidas de muestras de pacientes con periodontitis crónica. A los 30 días posinfección se fijaron muestras de corazón y arteria aorta para su procesamiento. En el grupo control no se encontraron alteraciones. En el grupo I se observó en el endocardio valvular abundante exudado fibrinoleucocitario y focos hemorrágicos. En el miocardio, neovascularización y sufusiones hemorrágicos y en la pared de vasos arteriales, engrosamiento intimal. En el grupo II se observaron depósitos lipídicos en el interior de las células endoteliales, estrías grasas y pequeños ateromas. El grupo III mostró en un 100 por ciento de los casos, placas ateromatosas bien detalladas con abundante depósito de colesterol, calcificaciones, hemorragias y neovascularización. La suma de estos factores de riesgo: dieta hiperlipídica e infección con bacterias periodontopatógenas, potenciarían la expresión de alteraciones cardíacas y coronarias, incrementando la formación de ateromas (AU)

A histomorphometric study of osteocytic lacunae in interradicular bone with periodontal disease.

Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Masson's trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

A histomorphometric study of osteocytic lacunae in interradicular bone with periodontal disease

Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Masson’s trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

A histomorphometric study of osteocytic lacunae in interradicular bone with periodontal disease.

Previous studies report on the differences in volume of osteocytic lacunae that are associated to different local and systemic bone pathologies. Alterations have also been reported in rats with periodontal disease. The aim of the present study was to assess the histomorphometric pattern of osteocytic lacunae of the interradicular septum in human molars with periodontal disease (PD). We took samples of the interradicular septum of 31 molars with indication of extraction of male and female patients, 18-55 years old, who attend the Department of Surgery II of the Faculty of Dentistry, National University of Cordoba and private centers. Clinical records were prepared for each patient. The corresponding radiographs were taken for all the patients. We studied 11 samples of molars with slight PD and 12 control molars free from PD. Ten samples of healthy bone corticals of vestibular or lingual tables obtained from histopathology archives were also assessed. Following extraction with atraumatic pincers, the interradicular septum was removed. The samples were fixed in buffered formaline, decalcified in EDTA and embedded in paraffin. Ten micrometer sections were stained with H&E and Massons trichromic technique. The sections were analyzed by light microscopy. A minimum of 50 lacunae were selected at random in each sample for histomorphometric evaluation. Semi-automatic evaluation of the area and diameters of the lacunae was performed employing an image analyzer and the PRO IMAGE PLUS software. The data showed that the volume of osteocytic lacunae of interradicular bone is larger than that of the cortical bone of the vestibular or lingual tables. The latter are more ribbon-shaped and their minor diameter is smaller. No differences were found between the osteocytic lacunae of the interradicular bone of healthy molars and that of molars with slight periodontal disease. Given that the experimental data evidenced volume changes in osteocytic lacunae of severe, inflammatory periodontal lesions, it would be interesting to examine the volume changes in osteocytic lacunae in patients with varying degrees of periodontal disease to examine the role of osteocytes in the development and progression of periodontal disease.

Kinetics and mechanisms of EDTA photocatalytic degradation with TiO2.

A complete study on the photocatalytic degradation of ethylenediaminetetraacetic acid (EDTA) over TiO2 has been initiated, to establish the influence of several parameters on the reaction rate, the nature of the intermediates and the kinetic regime. TiO2 (Degussa P25) suspensions containing EDTA at pH 3 at different concentrations were irradiated under near UV light. A Langmuirian behavior was observed, from which kinetic constants have been obtained. Experiments with 5.0 mM EDTA (zero order kinetic regime) were performed for 3 hours irradiation under different conditions. Under N2 bubbling, depletion of EDTA was very low. Under O2 bubbling, the concentration of EDTA decreased around 90%. However, the corresponding decrease of TOC ranged only between 4.5% and 9%. A higher TOC reduction (22% or more) was obtained by keeping the pH constant by HClO4 addition, or by hydrogen peroxide addition. Addition of 0.5 mM Fe(III) caused a dramatic increase on the initial rate of EDTA depletion and approximately a 32% TOC decrease. Analysis of the filtered solution was performed by ion chromatography and capillary electrophoresis to monitor the disappearance of EDTA and the formation of degradation products after different irradiation times. So far, glycine, ethylenediamine, formic acid, ammonium, iminodiacetic acid, oxalic acid and glyoxylic acid have been identified.

Simultaneous spectrophotometric determination of La, Ho, Mn 5-Br-PADAP complexes using multivariate calibration with partial least-squares (PLS) data evaluation.

A simple and fast analytical pocedure is proposed for the simultaneous spectrophotometric determination of lanthanum, holmium and manganese in synthetic ceramics, (La(0.8-x) Hox Sr0.2 MnO3), by using the partial least-squares (PLS) method. As chromogenic agent 5-Br-PADAP [2-(5-bromo-2-pyridylazo)-5-diethylaminophenol] was used, which form colored complexes with the three elements studied. To avoid metal hydrolysis, a mixture of ethanol and Triton X-100 at pH 9.5 was used for all experiments. A set of 17 calibration solutions measured throughout the 400-700 nm wavelength range was used in the calibration step. The concentration range for Mn(II) was 1-12 x 10(-6) mol L-1, while the range for the rare earth elements La(III) and Ho(III) was 2-8 x 10(-6) mol L-1. In order to demonstrate the applicability of the proposed method, a set of artificial samples containing the three analytes in variable proportions was prepared and analyzed. The analytical results obtained were quite acceptable with relative errors not greater than 7% in most cases.

Enlargement of periosteocytic lacunae associated to mechanical forces.

Demineralization of bone has been linked to the action of osteocytes via the process of osteocytic osteolysis. The aim of this study was to assess the influence of mechanical forces produced during orthodontic movements on the osteocytic lacunae. Orthodontic movements were achieved employing a device constructed "ad hoc" for rats that exerts a force of approximately 70 gr. The experimental animals and the corresponding controls were killed 48 and 96 hours after the onset of the experiment. Histologic sections oriented along the bucco-palatine axis were employed to measure the area of osteocytic lacunae to infer information on volume in keeping with standard stereological concepts. Regions alongside resorption areas of cortical bone and resting areas of palatine bone were evaluated. Osteocytic lacunae associated to erosive surfaces were rounded and rose markedly in area after the application of the orthodontic force (58.4 +/- 6 mm2). Elongated lacunae were present in relation to resting areas (24.8 +/- 2 mm2). The present study shows an association between the increase in size of osteocytic lacunae and the resorption fronts induced by the application of orthodontic forces. This finding would suggest that the osteocyte would participate in the resorption process of bone submitted to pressure.

Enlargement of periosteocytic lacunae associated to mechanical forces

Demineralization of bone has been linked to the action of osteocytes via the process of osteocytic osteolysis. The aim of this study was to assess the influence of mechanical forces produced during orthodontic movements on the osteocytic lacunae. Orthodontic movements were achieved employing a device constructed [quot ]ad hoc[quot ] for rats that exerts a force of approximately 70 gr. The experimental animals and the corresponding controls were killed 48 and 96 hours after the onset of the experiment. Histologic sections oriented along the bucco-palatine axis were employed to measure the area of osteocytic lacunae to infer information on volume in keeping with standard stereological concepts. Regions alongside resorption areas of cortical bone and resting areas of palatine bone were evaluated. Osteocytic lacunae associated to erosive surfaces were rounded and rose markedly in area after the application of the orthodontic force (58.4 +/- 6 mm2). Elongated lacunae were present in relation to resting areas (24.8 +/- 2 mm2). The present study shows an association between the increase in size of osteocytic lacunae and the resorption fronts induced by the application of orthodontic forces. This finding would suggest that the osteocyte would participate in the resorption process of bone submitted to pressure.

Enlargement of periosteocytic lacunae associated to mechanical forces.

Demineralization of bone has been linked to the action of osteocytes via the process of osteocytic osteolysis. The aim of this study was to assess the influence of mechanical forces produced during orthodontic movements on the osteocytic lacunae. Orthodontic movements were achieved employing a device constructed [quot ]ad hoc[quot ] for rats that exerts a force of approximately 70 gr. The experimental animals and the corresponding controls were killed 48 and 96 hours after the onset of the experiment. Histologic sections oriented along the bucco-palatine axis were employed to measure the area of osteocytic lacunae to infer information on volume in keeping with standard stereological concepts. Regions alongside resorption areas of cortical bone and resting areas of palatine bone were evaluated. Osteocytic lacunae associated to erosive surfaces were rounded and rose markedly in area after the application of the orthodontic force (58.4 +/- 6 mm2). Elongated lacunae were present in relation to resting areas (24.8 +/- 2 mm2). The present study shows an association between the increase in size of osteocytic lacunae and the resorption fronts induced by the application of orthodontic forces. This finding would suggest that the osteocyte would participate in the resorption process of bone submitted to pressure.

Formation of the VHL-elongin BC tumor suppressor complex is mediated by the chaperonin TRiC.

von Hippel-Lindau (VHL) disease is caused by loss of function of the VHL tumor suppressor protein. Here, we demonstrate that the folding and assembly of VHL into a complex with its partner proteins, elongin B and elongin C (herein, elongin BC), is directly mediated by the chaperonin TRiC/CCT. Association of VHL with TRiC is required for formation of the VHL-elongin BC complex. A 55-amino acid domain of VHL is both necessary and sufficient for binding to TRiC. Importantly, mutation or deletion of this domain is associated with VHL disease. We identified two mutations that disrupt the normal interaction with TRiC and impair VHL folding. Our results define a novel role for TRiC in mediating oligomerization and suggest that inactivating mutations can impair polypeptide function by interfering with chaperone-mediated folding.

Vinorelbine as neoadjuvant chemotherapy in advanced cervical carcinoma.

PURPOSE: To evaluate the efficacy and toxicity of vinorelbine (VNB) as single-agent neoadjuvant chemotherapy in advanced cervical carcinoma (ACC). PATIENTS AND METHODS: Between December 1993 and October 1995, 43 untreated patients with stages IIB to IVA squamous cell cervical cancer were entered onto this study. Forty-two patients are assessable for response and 43 for toxicity. The median age was 46 years (range, 28 to 65). Distribution by stages (International Federation of Gynecology and Obstetrics [FIGO]) was as follows: IIB, 18 patients; IIIA, one; IIIB, 19; and IVA, five. Therapy consisted of VNB 30 mg/m2 by 20-minute intravenous (IV) infusion repeated weekly for 12 injections and followed by radical surgery if feasible or definitive radiotherapy. Both staging and response assessment were performed by a multidisciplinary team. RESULTS: One patient was considered not assessable for response. A total of 493 cycles of therapy were administered and objective remissions were observed in 19 of 42 patients (45%; 95% confidence interval, 30% to 60%). Two patients (5%) had a complete response (CR) and 17 (40%) a partial response (PR); no change (NC) was observed in 16 (38%) and progressive disease (PD) in seven (17%). Six of 19 patients (32%) who achieved objective responses (ORs) underwent surgery. The median time to failure and median survival time have not been reached yet. There were no therapy-related deaths. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 35 patients (81%) and was grade 3 or 4 in seven (17%). Twelve patients (28%) developed peripheral neuropathy, while myalgias occurred in 10 (23%). Constipation was observed in nine patients (21%), one with a prolonged ileum. Phlebitis was recorded in 18 patients (41%). In contrast, emesis and mucositis were rarely observed. No patient developed alopecia grade 3. By the end of the twelfth course of treatment, the average received dose-intensity was 85.4% of that projected. CONCLUSION: VNB is an active drug against ACC with moderate toxicity. Its activity is among the highest reported for single agents. Further evaluation in association with other agents is clearly justified.

Ifosfamide and cisplatin as neoadjuvant chemotherapy for advanced cervical carcinoma.

A phase II trial was performed to evaluate the efficacy and toxicity of a combination of cisplatin (CDDP) and ifosfamide (IFX) as neoadjuvant chemotherapy in advanced cervical carcinoma (ACC). Between August 1991 and September 1993, 57 untreated patients with stages IIB to IVA were entered into this study. Median age was 44 years (range, 25 to 74 years). The distribution by stages (International Federation of Gynecology and Obstetrics) was as follows: IIB, 31 patients; IIIB, 21 patients; and IVA, 5 patients. Therapy consisted of IFX 2000 mg/m(2) 1-h i.v. infusion days 1 to 3; mesna 400 mg/m(2) i.v. bolus at hours 0 and 4, and 800 mg p.o. at hour 8; and CDDP 100 mg/m(2) on day 3. Cycles were repeated every 28 days for a total of three courses. Both staging and response assessment were performed by a multidisciplinary team. An objective response was observed in 30 of 56 patients (54%; 95% confidence interval, 41 to 67%). Four patients (7%) had a complete response (CR) and 26(46%) had a partial response (PR). Patients with CR or operable PR underwent surgery, otherwise received definitive radiotherapy. Toxicity was mild to moderate. There were no toxicity related deaths. These results indicate that IFX/CDDP is an active combination for ACC with mild toxicity. The results of phase III studies that evaluate the real impact of neoadjuvant chemotherapy are awaited.

High-dose cisplatin as neoadjuvant organ-preserving chemotherapy for squamous cell carcinoma of the larynx.

PURPOSE: We conducted this study to evaluate the efficacy and toxicity of fractionated high-dose cisplatin as neoadjuvant organ-preserving chemotherapy, followed by definitive radiotherapy, for untreated and advanced squamous cell carcinoma of the larynx. MATERIALS AND METHODS: From August 1990 to April 1994, 32 patients bearing previously untreated advanced squamous cell carcinoma of the larynx (12 stage III and 20 stage IV) received three courses of high-dose cisplatin (100 mg/m2 on day 1 and day 8 every 28 days) before definitive external radiation therapy with 65 to 70 Gy (180-200 cGy daily for 6-8 weeks). Twenty-eight patients were men; median age was 57 years (range, 31-69); and median performance status (ECOG) was 1 (0-2). RESULTS: With an average follow-up time of 18 months (range, 6-47), 30 patients are evaluable for response and 32 for toxicity. Responses after three courses of chemotherapy were: complete response, 18 patients (60%), and partial response, 7 patients (23%), for an overall response rate of 83%. Only one patient showed progressive disease. Fifteen patients (50%; 12 complete and 3 partial responders) had pathologic complete remission. Eighty percent of patients had no evidence of disease after the therapeutic program. Median disease-free survival was 24 months, and median overall survival was 28 months (range, 6-47). Overall, in 46% of all evaluable patients, organ preservation with acceptable function was achieved. Disease-free survival and larynx preservation were strongly correlated with pathologic complete remission. The average dose intensity received at the end of the third course of therapy was 47 mg/m2/week. There were no drug-related deaths. The main acute toxicity was grade 2-3 nausea and vomiting in 75% of patients. Two patients developed renal impairment after the first course of cisplatin. Ototoxicity (grade 2-3) was seen in 43% of patients, and peripheral neuropathy (grade 2-3) was observed in 12% of patients. In contrast, myelotoxicity and mucositis were mild. CONCLUSION: In conclusion, this strategy with fractionated high-dose cisplatin given on an outpatient basis is an attractive approach that produces a high rate of complete response and larynx preservation with an advantageous toxicity profile.

Evolutionary relationships among eubacterial groups as inferred from GroEL (chaperonin) sequence comparisons.

The essential GroEL proteins represent a subset of molecular chaperones ubiquitously distributed among species of the eubacterial lineage, as well as in eukaryote organelles. We employed these highly conserved proteins to infer eubacterial phylogenies. GroEL from the species analyzed clustered in distinct groups in evolutionary trees drawn by either the distance or the parsimony method, which were in general agreement with those found by 16S rRNA comparisons (i.e., proteobacteria, chlamydiae, bacteroids, spirochetes, firmicutes [gram-positive bacteria], and cyanobacteria-chloroplasts). Moreover, the analysis indicated specific relationships between some of the aforementioned groups which appeared not to be clearly defined or controversial in rRNA-based phylogenetic studies. For instance, a monophyletic origin for the low-G+C and high-G+C subgroups among the firmicutes, as well as their specific relationship to the cyanobacteria-chloroplasts, was inferred. The general observations suggest that GroEL proteins provide valuable evolutionary tools for defining evolutionary relationships among the eubacterial lineage of life.

Cloning, characterization, and functional expression in Escherichia coli of chaperonin (groESL) genes from the phototrophic sulfur bacterium Chromatium vinosum.

A recombinant lambda phage which was able to propagate in groE mutants of Escherichia coli was isolated from a Chromatium vinosum genomic DNA library. A 4-kbp SalI DNA fragment, isolated from this phage and subcloned in plasmid vectors, carried the C. vinosum genes that allowed lambda growth in these mutants. Sequencing of this fragment indicated the presence of two open reading frames encoding polypeptides of 97 and 544 amino acids, respectively, which showed high similarity to the molecular chaperones GroES and GroEL, respectively, from several eubacteria and eukaryotic organelles. Expression of the cloned C. vinosum groESL genes in E. coli was greatly enhanced when the cells were transferred to growth temperatures that induce the heat shock response in this host. Coexpression in E. coli of C. vinosum groESL genes and the cloned ribulose bisphosphate carboxylase/oxygenase genes from different phototrophic bacteria resulted in an enhanced assembly of the latter enzymes. These results indicate that the cloned DNA fragment encodes C. vinosum chaperonins, which serve in the assembly process of oligomeric proteins. Phylogenic analysis indicates a close relationship between C. vinosum chaperonins and their homologs present in pathogenic species of the gamma subdivision of the eubacterial division Proteobacteria.