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Biomedical subjects

R L Cabrini

Publications and source records attributed to R L Cabrini.

At least 91 records · Page 5Linked to original sources
PubMed1983

Histometric study of leukoplakia, lichen planus and carcinoma in situ of oral mucosa.

Leukoplakia, lichen planus and carcinoma in situ of human oral mucosa were analysed histometrically by light microscopy. Leukoplakia lesions showed a greater total nuclear density than lichen planus lesions. They had a similar basal nuclear density to carcinomas in situ. The total and basal nuclear areas were notably greater in carcinomas in situ, indicating the presence of larger nuclei in comparison to those of other lesions. We believe it to be possible to make a differential diagnosis based on numerical variables.

Carcinoma in Situ↗
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↗
PubMed1983

Ultrastructural study of osteodentin formation induced by irradiation.

A single dose of 16,000 rads was delivered to a 1 X 1.5 cm area of the cheek of 2 day old Wistar rats. The lower first molar region was removed 1, 3, 5 and 8 days postirradiation and processed for light and electron microscopy observation. The most distinct structural feature at optical level was osteodentin production in the dental papilla, which began at the level of the initiation of Hertwig's epithelial sheath and continued until the pulpal area was completely filled by osteodentin. At the ultrastructural level, ameloblasts exhibited large lipidic vacuoles and irregular intracytoplasmic secretory granules. Odontoblasts underwent multiple regressive alterations with vacuolization and numerous myelin figures. Pulpal cells exhibited a capacity for odontoblastic differentiation with formation of one or more odontoblastic processes and dentin matrix secretion. Thus, irradiation resulted in stimulation of a great potential for dentin production in these cells.

Animals↗
PubMed1983

Radiation effects on submandibular gland of the rat. Stereological and ultrastructural study.

The chronic effect of 2000 rd (20 Gy) of X-rays locally applied to the submandibular gland of Wistar young-adult male rats, was studied by stereology, and light and electron microscopic observations. They demonstrated that degenerative changes were observed during the first months after irradiation. Atrophic processes developed from 6 months onwards. In the acinar compartment, atrophy was progressive from the first months post-irradiation up to 9 months post-irradiation. Ductal cell membranes and mitochondrial damage were clearly detected at ultrastructural level. Nuclear fragmentation and secretory granules alterations were also frequently seen in the acinar compartment.

Animals↗
PubMed1982

Variations in epidermal cytochrome oxidase activity after local irradiation.

Cytochrome oxidase activity was evaluated histochemically as an index of mitochondrial damage after local irradiation with X-rays. It was determined by microphotometry on the tail skin of newly born Wistar rats four days after irradiation with doses ranging from 2 to 16 krad. The enzyme activity of the whole epidermis increased after irradiation, the increases being related to the increase in thickness of the epithelium which was observed as a response to irradiation injury. Within the dose range tested, the enzyme concentration (expressed per uni volume of tissue) decreased in relation to the dose applied. At the electron microscopy level, the cytochemical demonstration of cytochrome oxidase revealed an irregular reaction over the cristae, intramitochondrial vacuolization and partial homogenization of the matrix. Positive membrane fragments were seen around lipid droplets. This reaction confirms the mitochondrial origin of these previously observed radiation-induced vacuoles.

Animals↗
PubMed1981

Practical applications of the microphotometric quantification of histoenzyme reactions.

There are many histochemical reactions which can be used for the accurate topographic detection of enzymes in tissues. There are also many reports of applications of these techniques in which the results have been evaluated subjectively. However, only a few of these methods have been the subject of quantification, using different methodologies, most of them based on microphotometry. A critical analysis of these procedures has generally shown that they are valid either relatively or at an absolute level. Nevertheless, the routine application of these methods is not as widespread as one might expect. In this paper, the methodological developments that have taken place in the histochemical assay of some enzymes by microspectrophotometry are reviewed briefly. The enzymes include acid phosphatase, non-specific esterase, succinate dehydrogenase and cytochrome oxidase. These methods have given consistent and useful results when applied to our experimental models of irradiated skin, and thus seem useful for various other applications. The reasons why there have been so few applications for quantitative histochemistry are also discussed together with possible ways of making its use more general.

Acid Phosphatase↗
PubMed1981

Microspectrophotometric quantitation of DNA in bone tumors with giant cells (osteoclastoma, osteosarcoma and chondroblastoma).

A microspectrophotometric study of DNA content was carried out on cells from three types of bone tumor--osteoclastoma, chondroblastoma, and osteosarcoma--in all of which the formation of multinucleated giant cells occurs. Giant cells of osteoclastic type were present in all the tumors, with contents of DNA which were constant, uniform and diploid in character for each nucleus individually considered. Since there were no nuclei with reduced or increased content of DNA, mitotic proliferation or gemmation can be excluded. Instead, the evidence suggests the formation of giant cells through a mechanism of cellular fusion. In contrast, the stromal cells of the osteoclastomas and the chondroblastomas gave evidence of DNA synthesis, thus proving their proliferative capacity in both tumors. The osteosarcomas showed a very irregular distribution of DNA, and generally the nuclear content of DNA exceeded the diploid DNA content.

Bone Neoplasms↗
PubMed1978

Microspectrophotometric quantitation of the diaminobenzidine reaction for histochemical demonstration of cytochrome oxidase activity.

Polyacrylamide models in which an extract of cattle heart mitochondria was incorporated, as well as cryostat sections of tongue muscle and epithelium, were used to set up the conditions under which the histochemical reaction for the demonstration of cytochrome oxidase can be quantitated. Using diaminobenzidine in a concentration of 5.5 mM, cytochrome C in a fixed concentration of 76 micron and keeping the incubation medium away from direct light action, enzyme activity can be evaluated by means of direct microphotometry on tissue sections. Each biologic model requires previous individual determination of the measurement limits. These limits can be readily established by using a small chamber for the incubation medium, which can be placed in the microphotometer, allowing the reaction rate to be following using a single section.

3,3'-Diaminobenzidine↗
PubMed1978

Total and local X-radiation effects on 18F uptake of bones.

Flourine uptake in rat bones under local and total-body X-irradiation was studied. Data were obtained by measurements with a scintillation crystal counter and in the case of limbs by means of macro and microautoradiographies. The autoradiographic studies showed a higher concentration of the isotope in the metaphyseal area of the endochondral plate. Irradiation produced a depression of 18F uptake in both cases. An alteration in the mineralization mechanism due to irradiation is presumed.

Animals↗
PubMed1978

Radiation effects produced by the intra-articular injection of 32P.

Colloidal forms of radioactive isotopes are being used for the treatment of some articular diseases. The radiation effects of intra-articular injection of 0.25 mCi of 32P in the form of colloidal chromic phosphate were investigated in one of the knee joints of adult Wistar rats. The contralateral knee was used as a control. The animals were sacrificed one, 7, 14, 28 and 56 days later. Destructive changes were found after 56 days. The articular cartilage was atrophied and covered by a fibrous pannus. The growth cartilage was severely disorganized and there were deleterious effects on both cells and matrix.

Animals↗
PubMed1977

Volumetric modifications of X-irradiated keratinocytes.

The number of epithelial cells per unit volume of tissue (NV) and the relative volume (VV) occupied by the spinous and basal layers of X-irradiated and non-irradiated rat-tail epidermis were studied using techniques of stereologic cytology. By a simple calculation, the absolute volumes of basal and spinous keratinocytes were determined in irradiated (and in non-irradiated, control) epidermis, 24, 48, 72 and 96 h after exposure to a single dose of 16 Krads. During this post-irradiation period, the absolute volumetric values of both basal and spinous keratinocytes increased gradually, reaching a three-fold increase 96 h after irradiation. At the same time, the relative volume of the spinous layer increased from 58% to 75% of the total epidermis, whereas the volume fraction occupied by the basal layer decreased from 20% to 16%. These findings support previous evidence that lethally and sublethally damaged keratinocytes are capable of a metabolic effort resulting in a cell hypertrophy which in some circumstances could lead to repair and recovery from radiation damage.

Animals↗