Biomedical subjects

Angela M Ubios

Publications and source records attributed to Angela M Ubios.

6 recordsLinked to original sources

PubMed2006

Influence of short-term diabetes on osteocytic lacunae of alveolar bone. A histomorphometric study.

The aim of this study was to evaluate, for the first time, the histomorphometry of the cellular and lacunar features of the osteocytes of alveolar bone in acute streptozotocin-induced diabetic insulin-treated or untreated rats. Eighteen male Wistar rats weighing 200 to 260 g were assigned to one of the following groups: I) control group (C), II) diabetic group (DBT), and III) insulin treated diabetic group (DBT+INS). Experimental diabetes was induced by a single intraperitoneal injection of 60 mg/kg of body weight of streptozotocin. Insulin treatment began 24 h after the streptozotocin injection in animals of group DBT+INS in a dose of 4-6 IU of Humulin NPH insulin given as a single daily subcutaneous (s.c.) injection each morning between 07.00 and 10.00 h. The animals were euthanized on the 8th day. The upper maxillae were removed and fixed in buffered formalin, decalcified in EDTA, embedded in paraffin and stained with H-E for histologic and histomorphometric evaluation. Bone activity and lacunar density, osteocyte and empty lacunar densities, lacunar volume and lacunar shape were evaluated. Differences between variables were assessed by one-way ANOVA. Surface bone activity values revealed that bone resorption was significantly greater in the DBT group than in the C group (p < 0.05). Total lacunar density was significantly reduced in the DBT and DBT+INS groups as compared to control (p < 0.05). Concomitantly, a statistically significant reduction in osteocyte density and an increase, albeit not statistically significant, in empty lacunar density was observed in DBT and DBT+INS groups versus control. Lacunar volume did not exhibit statistically significant differences. The osteocyte lacunae in the DBT group lost their rounded shape and acquired intermediate shapes. This study reveals an early response of osteocytes to hyperglycemia, before systemic compensatory mechanisms are turned on. The effects are not always compensated by insulin treatment.

Alveolar Bone Loss↗

PubMed2005

Alterations of tooth eruption and growth in pups suckling from diabetic dams.

Several studies have confirmed a decrease in the quality and quantity of milk of mothers with diabetes during lactation. However, it remains unclear how maternal diabetes affects the offspring specifically during lactation. The aim of this study was to evaluate body and mandibular growth and tooth eruption in pups suckling from diabetic dams. The study was performed on 13 Wistar rat pups that were born to dams that were subjected to experimental diabetes on the day of parturition. Body weight and body size were recorded regularly throughout the study. The experimental pups and a group of eight age-matched pups suckling from nondiabetic dams were killed at weaning. Both hemimandibles were excised and fixed. Right hemimandibles were radiographed to assess mandibular growth and tooth eruption. The left hemimandibles were processed to obtain buccolingually oriented sections at the level of the first mesial root of the first lower molar. Histologic and histomorphometric studies were performed. Results showed that body weight and body size were significantly lower in experimental animals at weaning compared with their age-matched controls. Smaller mandible size and reduced tooth eruption in experimental animals compared with controls were observed. The length, width, and bone volume of the developing alveolus were reduced in experimental animals compared with controls. The results obtained in this study allow the conclusion that suckling from diabetic dams results in reduced body, mandible size, and tooth eruption of the pups at weaning.

Animals↗

PubMed2004

Effect of orthodontic forces on root resorption in molars submitted to experimental periodontitis.

The present experimental study addresses the issue of the development and size of root resorption areas in molars of rats submitted to orthodontic forces of 51 or 75 g and the induction of periodontal disease by placing a cotton ligature around the cervix of the first upper molars for 48 hours. Immediately on removal of the ligature or 48 hs later we put an orthodontic device in place. The device comprised two steel bands. The arms of a helicoidal spring that exerted force towards palatine passed through the palatine tubes welded to the bands. The number of odontoclasts and the percentage of root resorption areas were determined histomorphometrically on bucco-palatine sections obtained at the level of the central roots. The data showed an increase in root resorption areas when the orthodontic forces were applied to molars of rats following the induction of periodontitis. The magnitude of the force was proportional to the size of the resorption areas and to the number of odontoclasts. Both these end-points exhibited smaller values when the forces were applied once the inflammatory reaction had subsided. The present study shows that the risk of development of root resorption areas in patients with periodontal disease submitted to orthodontic treatment would be lower if lighter forces were applied and treatment were delayed until the inflammatory signs have subsided.

Animals↗

PubMed2003

Alveolar bone response in an experimental model of renal failure and periodontal disease: a histomorphometric and histochemical study.

BACKGROUND: Chronic destructive periodontal disease is characterized by gingival inflammation, periodontal pocket formation, and bacterial plaque that lead to alveolar bone destruction. Polymorphonuclear neutrophil leukocytes (PMNs) are the first line of defense against infection caused by dental plaque bacteria. Renal patients present functional abnormalities of PMN, including impaired chemotaxis, phagocytosis, and intracellular killing of bacteria. In view of the above, the aim of this work was to evaluate the effect of renal failure on bone damaged by periodontal disease using histomorphometric and histochemical parameters. METHODS: Twenty male Wistar rats weighing 250 g were assigned to one of the following four groups: 1) control (no treatment); 2) renal failure (RF); 3) periodontal disease (PD); and 4) renal failure plus periodontal disease (RF+PD). All the animals were sacrificed 31 days after the onset of the experiment. Mesio-distally oriented sections of the first lower molar were obtained for histomorphometric and histochemical evaluation. RESULTS: Total erosion, active erosion, and total number of tartrate-resistant acid phosphatase-positive (TRAP+) osteoclasts were found to be increased in the RF+PD group compared with the PD group. CONCLUSION: Our results demonstrate increased bone resorption in animals with untreated renal failure and periodontal disease, and thus indicate that the release of different factors by inflammatory cells is magnified, accelerating the progression of the disease in this animal model.

Acid Phosphatase↗

PubMed2002

Experimental renal failure and iron overload: a histomorphometric study in the alveolar bone of rats.

Renal failure is a serious disease of a relatively high incidence, which among other lesions, causes bone alterations. These patients frequently suffer from anemia that is generally treated with iron. Given that iron overload inhibits bone formation, our aim was to evaluate the effect of iron on the interradicular bone of animals with experimental renal failure. Acute renal failure was induced in male rats by 5/6 nephrectomy. The animals were subjected to iron overload in the form of daily intraperitoneal injections of 88 mg/kg body weight of iron-dextran over a period of 16 days. Tetracyclines were injected intraperitoneally 14 days apart to evaluate dynamic parameters of bone. Serum urea and creatinine levels were evaluated immediately before the animals were killed on day 30. Static and dynamic histomorphometric measurements were performed. The data indicate that the iron overload modified the response of the renal failure animals which showed decreased interradicular bone volume and adynamic bone disease, characterized by reduced cell activity. These results should be taken into account when renal failure patients treated with iron must undergo dental treatments that depend on bone forming activity for their success.

Acute Kidney Injury↗

PubMedDate not supplied

Exposure to subcutaneously implanted uranium dioxide impairs bone formation.

The introduction of uranium particles into subcutaneous tissue is a risk that affects workers engaged in the extraction, purification, and manufacture of uranium, as well as soldiers who are wounded with uranium shrapnel. The authors evaluated the effect of an internal source of an insoluble form of uranium on bone. Uranium dioxide powder (0.125 gm/kg body weight) was implanted subcutaneously in rats. After 30 days, animals exposed to uranium weighed less than controls. Bone formation activity in endochondral ossification and bone growth were also lower in the experimental animals, as evidenced by histomorphometric and morphometric methods. This is the first study to report bone damage resulting from continuous, nonlethal exposure to an insoluble compound of uranium dioxide over a period of 30 days.

Animals↗