Analisis Pertumbuhan Kartilago Epifisialis Os Tibia Fetus Mencit (Mus musculus L.) Swiss Webster Setelah Induksi Ochratoxin A Selama Periode Organogenesis

The aims of this study were determined the effects of Ochratoxin A (OTA) on growth of fetus tibia epiphyseal cartilage during organogenesis period. Twenty four pregnant mice were divided randomly into 4 groups of 6. Ochratoxin A was dissolved in sodium bicarbonateand administered orally on seventh to fourteenth days of gestation at dosage of 0.5, 1.0, 1.5 mg/kg bw, respectively. The remaining were used as control. The fetal tibia was taken after the 18 th day of pregnancy. The growth of tibia epiphyseal cartilages were observed histologically using Erlich’s Haematoxylin-Eosin Stain. The result of this study indicated that OTA caused decreased thickness of the rest zone, proliferative zone, maturation zone and calsification zone of the fetus tibial growth plate significantly. Key words: Ochratoxin A, tibia, cartilage, and thickness.

Cyclic Induction and Rapid Movement of Sequential Waves of New Smooth-Ended Ameloblast Modulation Bands in Rat Incisors as Visualized By Polychrome Fluorescent Labeling and Gbha-Staining of Maturing Enamel

The movement of smooth-ended ameloblast modulation bands was studied in continuously erupting Tincisors of male Wistar rats, with fluorochromes such as calcein (green), xylenol orange (red), tetracycline (yellow), and calcein blue (turquoise) used to label maturing enamel intensely at sites delimiting the location of smooth-ended ameloblasts at the time of injection. Hence, a fluorescent label of one color was injected to establish a reference position at time "0" followed by one or more fluorescent labels of different colors, or by in vitro enamel staining with glyoxal bis(2-hydroxyanil)(GBHA), at various times after the initial injection. For example, rats injected with calcein followed by xylenol orange at 10 min or two, four, six, or 12 hr later showed zero, 367, 888, 1259, and 2833 μm incisal movement, respectively, of the red bands relative to companion green fluorescent bands in the mandibular incisors. If one takes into account the eruption rate for these teeth (27.1 μm per hr), these data were indicative of a coordinated, wave-like movement of smooth-ended ameloblast modulation bands incisally along the length of the tooth at a mean rate of 243 μm per hr. Measurements and graphic plots of the distribution of smooth-ended ameloblast bands in histological sections and in GBHA-stained teeth revealed not only that such bands were positioned at all possible locations along the length of the maturation zone within a group of different teeth, but also that the average interband distance equaled about 2100 μm in the apical part of the maturation zone. Hence, new modulation waves appear to arise near the region of post-secretory transition and travel along the ameloblast layer toward the gingival margin about once every 8.5 hours. This suggests that a given cohort of ameloblasts may modulate as frequently as three times a day and complete a minimum of 45 modulation cycles by the end of enamel maturation.

Calbindin-D 28K Localization in Rat Molars During Odontogenesis

Specific antiserum raised against Calbindin-D28K, a vitamin D-dependent calcium-binding protein (CaBP) isolated from chick intestine, was used for localization of the protein in developing rat molars. Previously, CaBP had been localized in specific cells associated with the continuously erupting rat incisor: late pre-secretory ameloblasts, secretory and maturation zone ameloblasts, stratum intermedium cells adjacent to ameloblasts in the late zone of enamel secretion, and papillary cells underlying maturation zone ameloblasts. In this study, the peroxidase anti-peroxidase technique was used for localization of CaBP in histological sections of rat mandibles from 18-day-old rat embryos through 20-day-old neonates. CaBP was not detected in any cells of the enamel organ, dental papilla, or dental sac during early odontogenesis from the dental lamina stage through the advanced bell stage. The protein first appeared in secretory ameloblasts which were situated opposite odontoblasts with newly secreted dentin. CaBP was present in the cytoplasm of more mature ameloblasts, but not in less mature ameloblasts. Some stratum intermedium cells subjacent to well-developed secretory and maturation zone ameloblasts also contained CaBP. The protein was not detected in odontoblasts, pulp cells, or other cells associated with the developing molars. It was also absent from the demineralized enamel and dentin matrix. In developing rat molars, the time-course of appearance of CaBP, a protein dependent for its synthesis on the vitamin D endocrine system in other organ systems, suggests a potential direct role of this hormonal system in enamel mineralization.