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Biomedical subjects

A M Ubios

Publications and source records attributed to A M Ubios.

At least 19 recordsLinked to original sources
PubMed1992

Mandibular growth and tooth eruption after localized x-radiation.

The effect of localized x-radiation on the growth of mandibular bone and molar eruption was evaluated by morphometric methods. A dose of 20 Gy of x-radiation was given to the molar zone of growing rats. The animals were then killed in groups at 30 and 60 days postirradiation. Two groups of nonirradiated, age-matched rats were used as controls. Parameters related to molar eruption, mandibular length, and mandibular height were measured on lateral radiographs. The results obtained showed that the values of the biometric parameters were lower in experimental than in control animals. Odontoblastic atrophy, alveolodentary ankylosis, and meager or no root formation were the most conspicuous histologic findings. Osteodentin was found between canaliculary dentin and bone in cases of ankylosis. The morphometric data presented confirm the probability of alterations in mandibular growth and tooth eruption following x-radiation and suggest that this be considered in planning radiotherapy in children.

Alveolar Process↗
PubMed1991

Uranium inhibits bone formation in physiologic alveolar bone modeling and remodeling.

The toxic effect of uranium (U) on bone modeling and remodeling was studied by performing histomorphometric measurements in the periodontal cortical bone of rats. Two different single intraperitoneal doses of uranyl nitrate (238U) were administered to two sets of rats respectively (2 and 0.8 mg/kg body wt). Rats treated with the first dose were killed 14 days postinjection (PI) and those treated with the second were killed 14, 30, and 60 days PI. The results revealed a decrease in bone formation in rats treated with uranium. On the remodeling side the decrease in bone formation was coupled to an increase in bone resorption on the 14th day PI. On the modeling side no bone resorption was observed and the decrease in bone formation was linked to an increase in resting bone zones. Bone formation depression as a key event in U intoxication is stressed.

Animals↗
PubMed1991

Effect of calcitonin on alveolar wound healing.

The effect of calcitonin (CT) on alveolar wound healing was studied with histomorphometric methods. Wistar rats weighing 80-90 g were submitted to extraction of the three mandibular molars. Half of them were injected intraperitoneally with daily therapeutic doses of CT. The control group received no further treatment. All the rats were killed 14 days after the onset of the experiment. Bone healing was impaired in CT treated animals and involved a more intense bone remodeling activity. Bone resorptive areas were present both on the profiles of the newly formed bone and on the alveolar ridge surface. These results suggest that CT would accelerate the process of bone healing.

Alveolar Process↗
PubMed1989

Tetracycline in uranyl nitrate intoxication: its action on renal damage and U retention in bone.

In acute intoxication, uranium (U) not only inhibits bone formation but its excretion in urine also causes renal damage. The former effect is ameliorated by tetracycline (TC), probably due to its chelation property, which might also prevent U deposition in bone. Chemical determination of U incorporated in bone and a histological study of the kidneys were performed on animals injected with U and then treated with TC. The results showed that TC was unable to prevent the binding of U to bone while it exacerbated U-induced renal damage.

Animals↗
PubMed1986

Alveolar wound healing after x-irradiation: a histologic, radiographic, and histometric study.

Healing of extraction wounds in rats following cephalic irradiation was studied by histologic, radiographic, and histometric methods 14 days after tooth extraction. Irradiation was given at 0, 3, and 7 days after surgery in doses of either 15, 20, or 30 Gy. No significant differences were seen with the different doses given seven days post-extraction. However, socket healing was delayed when irradiation was given immediately and three days after extraction. On the basis of these observations, it is recommended that radiation not begin until at least one week after the extraction of teeth.

Alveolar Process↗
PubMed1986

Effect of diphosphonate on the prevention of X-radiation-induced inhibition of bone formation in rats.

A histologic and histometric study of the effect of EHDP (ethane-1-hydroxy-1,1-diphosphonate) on the alveolar wound healing of irradiated animals is presented. This drug was selected based on its osteosclerotic effect when applied at low doses. The three left mandibular molars of 80 male Wistar rats were extracted. The rats were grouped into 4 sets of 20 rats each. Group I received no further treatment; Group II received daily intraperitoneal injections of EHDP (7.5 mg/Kg of body weight during 10 days); Group III: 15 Gy of X-radiation were applied to the head; and Group IV were irradiated and injected with EHDP as were animals of Groups III and II. Half of the animals were killed after 14 days and the other half 30 days post-extraction. Sections were made at the level of the mesial socket of the first molar in a bucco-lingual orientation, on which histometric determinations of bone activity were made. The results showed the attenuation of the inhibitory effect of radiation on bone formation when the animals were treated with EHDP.

Alveolar Process↗
PubMed1985

Alveolar wound healing alteration under uranyl nitrate intoxication.

The deposit of uranium compounds in calcifying zones has been demonstrated in bone. Nevertheless, no studies on the effect of uranium on osteogenesis have been performed. A histologic and histometric study of the effect of a single intraperitoneal injection of 2 mg/kg of body weight of uranyl nitrate on bone formation is presented. It was performed on rats' healing sockets, 14 days after tooth extraction. The alveolar bone volume (15 X 10(5) micron vs. 34 X 10(5) micron2), total bone formation areas (4.85% vs. 19.55%), and volume density of bone in the alveolar apical third (0.26 vs. 0.40) were significantly lower in intoxicated animals than in the controls. These results indicate the inhibitory effect of uranyl nitrate on bone formation.

Alveolar Process↗
PubMed1985

Scanning electron microscopy of human submandibular gland.

The fracture surface of human submandibular gland analyzed by scanning electron microscopy is studied here. Acini showed spherical granules of 0.7 +/- 0.28 micron diameter, their most distinctive feature. Some empty, septate cavities found contiguous to serous acini were considered to be mucous acini. Striated ducts had a circular lumen, with microvilli forming prominences. Blebs, some intact and others ruptured, were interpreted as apocrine secretion. The 'separating zone' of the striated cells was distinguishable from the rest of the cell because the structure of the cell was granular whereas the 'separating zone' was fibrillar.

Adult↗
PubMed1985

Virus-like intranuclear inclusions in giant cell tumor of bone.

An ultrastructural study of 13 cases of typical giant cell tumor of bone (GCT) revealed the presence of virus-like intranuclear inclusions (INI), morphologically identical to those reported in Paget's disease of bone. In two giant cells of two different patients, INI were found only after careful survey of a great number of cells. This finding, coupled with the scarcity of GCT with similar inclusions reported in the literature, reveals the extreme rarity of this finding and leaves open to discussion the specificity of these INI even in Paget's disease, as well as the possible etiological significance in giant cell tumor of bone.

Bone Neoplasms↗
PubMed1984

Effects of acute intoxication with uranyl nitrate on bone formation.

The alteration of bone formation by an acute intoxication with uranyl nitrate is demonstrated by histologic and histometric methods. When compared with the controls, intoxicated animals showed a markedly lower density in healing sockets, while bone formation was reduced in healing sockets as well as in metaphyseal bone.

Animals↗
PubMed1984

Salivary gland tumors induced by 32P.

The oncogenic power of 32P was demonstrated in salivary glands. An intraglandular injection of 0.25 mCi of chromic colloidal phosphate (32P) was administered to young adult Wistar rats. Seven months post-injection, tumors began to appear in the neck region in 64% of the rats. The tumors were sarcomas (50%), carcinomas (35.70%), and carcino-sarcomas (14.28%).

Animals↗
PubMed1983

Radioactive-induced tumors by phosphorus-32 as colloidal compound.

Chromic colloidal phosphate labeled with 32P, which has been proposed for the treatment of several articular diseases, was injected intra-articularly in the knee joint of adult Wistar rats. After a 270 days minimum latent period, tumors began to appear in the injected zone, to a 70% frequency. Ten lung metastases were detected. In five cases, squamous cell carcinomas were induced in the injected area. The relevance of a sound evaluation of the risk involved in treatments with radioactive isotopes, is discussed.

Animals↗
PubMed1983

Freeze-fracture surface of salivary glands of rat observed by scanning electron microscopy.

The structure of parenchymal components of rat submandibular glands observed with scanning electron microscopy is presented. The glands were fixed, submerged in liquid nitrogen, cryofractured, dehydrated and critical-point-dried. The fracture surface displayed the acini, granular ducts and striated ducts. Acini exhibit a typical sponge-like pattern of irregular and empty cavities. Granular ducts are lined by bulging cells laden with numerous secretory granules. Their diameter ranged from 0.2 to 3.2 microns, with a mean value of 1.240.4 microns. Measurement of the actual granules was rendered possible by direct observation. Striated ducts exhibited a cribiform pattern near the basal cell region which corresponds to infoldings of the basal cell membrane.

Animals↗