Biomedical subjects

J Tolivia

Publications and source records attributed to J Tolivia.

At least 37 records · Page 2Linked to original sources

PubMed1994

Glucocorticoids and androgens up-regulate the Zn-alpha 2-glycoprotein messenger RNA in human breast cancer cells.

We have studied the hormonal regulation of the gene encoding Zn-alpha 2-glycoprotein (Zn-alpha 2-gp), a human protein with a high degree of amino acid sequence similarity to class I histocompatibility antigens that is produced by a specific subset of breast carcinomas. Northern blot analysis revealed that dexamethasone and 5 alpha-dihydrotestosterone strongly induced the accumulation of Zn-alpha 2-gp mRNA in T-47D human breast cancer cells. Furthermore, the effect of these two hormones was shown to be additive, since the combination of both hormones produced a stimulation of Zn-alpha 2-gp mRNA of at least 3-fold over that produced by either hormone alone. By contrast, the addition of 5 beta-dihydrotestosterone, 17 beta-estradiol, or progesterone failed to induce the expression of Zn-alpha 2-gp. The stimulatory effect of glucocorticoids and androgens on Zn-alpha 2-gp expression was produced in a time and dose dependent manner, without significantly affecting the cell proliferation rate. A time-course study demonstrated that the induction of Zn-alpha 2-gp mRNA by androgens and glucocorticoids reached a level of 4 or 3.2-fold over the untreated control after seven days of incubation in the presence of a 10(-7) M concentration of 5 alpha-dihydrotestosterone or dexamethasone, respectively. A dose-response study showed that as little as 10(-11) M of 5 alpha-dihydrotestosterone or dexamethasone produced an accumulation of Zn-alpha 2-gp mRNA of 2.4 or 2.1-fold over the control, respectively. On the basis of these results, we propose that Zn-alpha2-gp may be useful as a biochemical marker of breast carcinomas with a specific pattern of hormone responsiveness in whose development glucocorticoids and/or androgens may play a significant role.

Androgens↗

PubMed1994

Expression and prognostic significance of apolipoprotein D in breast cancer.

Apolipoprotein D (apo D) is a glycoprotein involved in the human plasma lipid transport system and present at large amounts in cyst fluid from women with gross cystic disease of the breast. Apo D expression in breast carcinomas was examined by immunoperoxidase staining of a series of 163 tumors. A total of 60 (36.8%) tumors were negative for apo D immunostaining, 28 (17.2%) carcinomas were weakly positive, 33 (20.2%) were moderately stained, whereas the remaining 42 (25.8%) tumors were strongly stained with the specific antibodies. No significant correlation was found between apo D content and tumor size, lymph node involvement, or biochemical parameters such as estrogen receptors, cathepsin D, or pS2 protein. However, the finding of a significant association between apo D and menopausal status of patients or differentiation grade of tumors, with apo D values being lower in tumors from premenopausal women or in poorly differentiated carcinomas, suggested a potential value of this glycoprotein as a prognostic factor in breast cancer. Preliminary analysis of relapse-free survival and overall survival in a subgroup of 152 women with a mean follow-up of 42 months confirmed that low apo D values were significantly associated to a shorter relapse-free survival and poorer survival. According to these data, we propose that apo D in combination with other well-established prognostic factors may contribute to more accurately identify subgroups of breast cancer patients with low or high risk for relapse and death.

Adult↗

PubMed1993

Rostrocaudal changes in neuronal cell size in human lateral vestibular nucleus.

A cytoarchitectonic and morphometric study of the human lateral vestibular nucleus (LVN) is presented. In sagittal sections, the LVN appears as a triangular cell group rostrally located near the motor trigeminal nucleus and caudally near the vestibular root. The estimated volume is 13.49 mm3 with a neuronal population of 25,046 cells and 1855 neurons/mm3 in density. The average neuronal cross-sectional area changes from a minimum caudally (380.02 +/- 7.23 microns 2) to a maximum rostrally (825.16 +/- 25.10 microns 2). Four types of neurons can be observed: small (< 200 microns 2), medium (200-500 microns 2), large (500-100 microns 2) and giant or Deiter's cells (> 1000 microns 2). The small and medium cells constitute 62%, large cells 26% and the giant cells only 12% of the neuronal population.

Adult↗

PubMed1993

An electron microscopic study of the harderian gland of the Syrian hamster with particular reference to the processes of formation and discharge of the secretory vacuoles.

The lipid-secreting cells of the Harderian gland of the Syrian hamster were studied using light, transmission, and scanning electron microscopy. Three morphologically different secretory cell types are identified in the gland: type I and II cells of the male gland and, distinct from either, the female gland cell. In all secretory cell types, lipid droplets in the cytoplasm were surrounded by unit membranes. Ultrastructural evidence of the involvement of the Golgi apparatus in the formation of the secretory vacuoles was obtained. The process of secretion involved the fusion of the boundary unit membrane of the vacuole with the plasma membrane and the release of the vacuolar content alone into the lumen. No evidence of holocrine processes was observed in this study. In addition to lipids, vacuoles contained materials whose solubility properties clearly differed from those of lipids. There appear to be variations in the ultrastructural characteristics of the vacuole content of the different types of secretory cell.

Animals↗

PubMed1993

Expression of pepsinogen C in human breast tumours and correlation with clinicopathologic parameters.

We have examined by immunohistochemistry the ability of breast carcinomas to produce pepsinogen C, an aspartyl proteinase usually involved in the digestion of proteins in the stomach. A total of 113 out of 245 breast tumours (46%) were positive for pepsinogen C immunostaining. There was a significant association between pepsinogen C and oestrogen receptors with proteinase levels higher (HSCORE) in oestrogen receptor positive tumours than in oestrogen receptor negative. There was also a significant association between pepsinogen C and histological grade, pepsinogen C levels being higher in well and moderately differentiated breast carcinomas than in poorly differentiated tumours. On the basis of these results, we suggest that pepsinogen C may be useful as a marker of good prognosis in breast cancer.

Adult↗

PubMed1993

Morphometric analysis of the vestibular complex in the rat.

The characteristics of the four major vestibular nuclei and accessory cell groups in the rat have been studied in serially cut horizontal sections. Camera lucida drawings of the vestibular nuclei and their neurons were made in these sections and subjected to a computerized image analysis. The dimensions (volume and length) and the number of cells of each vestibular nucleus were obtained, as well as morphometric parameters of their neurons (cross-sectional area, maximum and minimum diameter, and shape). These parameters were statistically analyzed by comparing the cell population from different nuclei and different parts of each nucleus. Of the major nuclei, the medial, which is the largest, has the greatest number of cells, its neurons being the smallest of all the nuclei, with the size of cells decreasing in a rostrocaudal direction. In contrast, the lateral nucleus contains the fewest cells but also the largest ones. Neurons of the superior and descending nuclei are of an intermediate size and number, with a rostrocaudal decrease in the size of the descending nucleus cells. In addition, minor nuclei are identified and described in their relationship to the other structures in the brain stem. The relevant aspects of the anatomical information in regard to functional roles are reviewed.

Animals↗

PubMed1992

Postnatal development of the harderian gland in the Syrian golden hamster (Mesocricetus auratus): a light and electron microscopic study.

The main objective of the present investigation was to study the morphological and chronological aspects of the development of the Harderian gland in the Syrian golden hamster. Tissues were obtained from male and female hamsters at days 1,3,5,7,10,12,15,17,20,27,37,46, and 90 after birth and processed for light and transmission electron microscopy. The present observations indicate that a well-defined temporal sequence in microscopic and ultrastructural modification is recognizable in the development of the hamster Harderian gland. Four stages of development were proposed. Between days 1-5 (first stage), the gland shows characteristics of an immature structure. The glandular cells contain many free ribosomes, few and small organelles, and large irregular-shape nuclei. Between days 7-17 (second stage), there is a marked increase of organelles involved in synthesis and secretion. The gland begins the secretion of lipids and porphyrins, but no morphological differences between male and female glands are observed. Between days 20-36 (third stage), the morphological differences between the two sexes appear and progressively develop. In 45-day-old hamsters, the Harderian gland possesses the structural characteristics of adult glands, and further developmental changes are essentially quantitative in nature (fourth stage). At all stages of development, the population of secretory cells has a uniform appearance. The morphological results are discussed as well as the possible relationship of this temporal sequence with hormonal changes.

Aging↗

PubMed1992

An ultrastructural study of myoepithelium maturation during postnatal development of the hamster Harderian gland.

This study reports the ultrastructural cell modifications in the myoepithelium of the Harderian gland during the postnatal development of the Syrian hamster. Tissues were obtained from male and female hamsters at days 1, 3, 5, 7, 10, 12, 15, 17, 20, 27, 37, 46 and 90 after birth, and processed for transmission electron microscopy. Electron microscopy was coupled with point counting methods to quantitate changes in several subcellular organelles during the course of myoepithelial cell maturation. The myoepithelial cells in this gland remained immature at birth. The earliest age of development when organized bundles of microfilaments were observed was 7 days. By the 12th day, the myoepithelial cells had developed most of their specific characteristics and resembled the mature form. Myoepithelial cells mature synchronously with each other and with the secretory cells. No undifferentiated myoepithelial and myoepithelial cells, the secretory endpieces of the adult hamster Harderian gland contain a third cell type which resembles the myoepithelial cell in shape and has an extremely electron-lucent cytoplasm lacking microfilament bundles.

Animals↗

PubMed1991

A new rapid silver impregnation for neuronal bodies on methacrylate sections.

A simple and rapid method for the impregnation of neuronal bodies applicable to methacrylate embedded sections is described in the present paper. Sections of 10-12 microns in thickness were attached to slides, placed in mordant for 1 min, rinsed in distilled water and impregnated in ammoniacal silver solution for 1 min. They were then rinsed in absolute ethanol for 30 s and developed in 50% formalin. Sections were toned in 0.25% gold chloride, reduced in 10% oxalic acid and fixed in 5% sodium thiosulfate. After washing, the sections were dehydrated through 90% and absolute ethanol, cleared in eucalyptol, and mounted in the usual way. When this method is used most of the neuronal somata and proximal dendritic trees are impregnated. Frequently some glial cell are also weakly impregnated but their density does not obscure the neurons.

Animals↗

PubMed1990

Ultrastructural study of lamellar and nucleolus-like bodies in the harderian gland during postnatal development of the hamster (Mesocricetus auratus).

Membranous structures identified as lamellar bodies (LBs) and dense intracytoplasmic bodies referred to as nucleolus-like bodies (NLBs) have been found in the hamster Harderian gland during neonatal stages. Both structures appear between 8 and 12 postnatal days, coinciding with the beginning of secretory activity. LBs in males and NLBs in both sexes gradually decrease in number with further differentiation of the glandular cells. The morphological features of these cytoplasmic structures are described, and their origin as well as their possible functional significance are discussed.

Animals↗

PubMed1990

Circadian changes in synaptic ribbons and spherules in pinealocytes of the Syrian hamster (Mesocricetus auratus).

In the present study, "synaptic" ribbons were studied morphologically and quantitatively in hamster pineal gland. The number of ribbons and spherules of hamster pinealocytes was counted over a 24-h period. The 24-h variations in the quantity of "synaptic" ribbons were found to parallel fluctuations in pineal melatonin concentrations. No significant circadian changes were observed for "synaptic" spherules, indicating different roles for these two structures.

Animals↗

PubMed1989

Differential thionin block staining of nerve cells and fibers for paraffin-embedded material in mammalian central nervous system.

A differential staining method of myelinated fibers and nerve cell bodies applicable to whole blocks of mammalian central nervous tissue is described. Experimental material fixed by perfusion or necropsy material fixed in block can be used. Blocks of 2 mm in thickness were obtained with a vibratome, immersed in 50% ethanol for 7 h and stained for 1 week in the following solution: 0.3% thionine, 5% formaldehyde and 5% acetic acid. After the staining period the blocks were washed in distilled water, dehydrated through graded alcohols, cleared in butyl acetate and infiltrated in paraffin. Sections of 10 microns in thickness were obtained, attached to slides, dewaxed in xylene and coverslipped with mounting media in the usual manner.

Animals↗

PubMed1989

Central vestibular projections of primary cervical fibers in the frog.

The origin of cervicovestibular inputs was documented in frogs, as well as the number of fibers, site of projection, and their distribution within the nuclei. The first spinal nerve in 15 frogs was labeled with extracellular injections of horseradish peroxidase. The brain stem and the posterior root were sectioned serially. The trajectories of the fibers in the central nervous system were reconstructed, and the number and diameters of the fibers in the posterior root were determined. The average number of fibers in the first posterior root was 143 +/- 6.2, their number decreasing exponentially with increased diameter. After entering the spinal cord the fibers were located in the dorsal funiculus. The thick and medium-sized fibers coursed medially in relation to the thin ones, giving collaterals to the spinal cord and to the obex region. The thinnest fibers projected to the reticular formation and nucleus of the solitary tract. Only collaterals from fibers of medium and thick caliber reached the vestibular area in their trajectory to the cerebellum (spinocerebellar fibers). All the vestibular nuclei received collaterals and endings from the spinocerebellar fibers, the ventral nucleus being the most innervated. The total number of branches for the vestibular area, however, was very small. The results of this experiment are correlated with physiological and anatomical findings described in the literature.

Animals↗

PubMed1988

New technique for differential staining of myelinated fibers and nerve cells on paraffin sections.

A simple, rapid method for the differential staining of myelinated nerve fibers and nerve cell bodies, applicable to sections of central nervous system pieces embedded in paraffin, is described. Experimental material fixed by perfusion with mixed aldehydes or necropsy material fixed in formaldehyde can be used. Constant and homogeneous results are obtained with this technique, and the most important characteristic is the absence of differentiation in either of the steps: staining of myelinated fibers and staining of nerve cell bodies. Sections 15 microns thick were attached to slides, dewaxed, and hydrated. After hydration, sections are mordanted (30 min) in 2.5% iron alum (SO4)2FeNH4, and rinsed (1 min) in distilled water. Staining is for 180 min in the following solution: 5 ml freshly made 20% alcoholic hematoxylin diluted with 25 ml of distilled water and 25 ml of absolute ethanol to which 10 ml of 1% Li2CO3 is added. The sections are washed in distilled water (5 min) and stained during 5 min in the following solution: 0.2% pyronine, 20% formaldehyde in distilled water. The sections are dehydrated through 96% and absolute ethanol, cleared in eucalyptol, and mounted in Eukitt. Myelinated fibers appear dark blue, whereas nerve cell bodies are stained red and the cell nucleoli dark blue. This procedure provides an adequate contrast for observation and photography.

Animals↗

PubMed1987

Differential technique to stain nerve cells and fibers in methacrylate sections.

A simple method for the simultaneous staining of nerve cells and fibers, applicable to sections of pieces embedded in methacrylate, is described. Sections of 12 micron in thickness were attached to slides and stained for 10-18 hours in the following solution: 0.03% thionin, 0.5% formaldehyde, 0.5% acetic acid in distilled water. They were then rinsed in acetic water (0.5% acetic acid) for 30 seconds, washed in distilled water, dehydrated through 96% and absolute ethanol, cleared in eucalyptol, and mounted in Eukitt.

Animals↗

PubMed1987

A new rapid silver impregnation for neuronal bodies.

Frozen sections of avian and rat brains routinely fixed in 6% glutaraldehyde/2% paraformaldehyde and left in phosphate buffer for 1 month are cut at 15-20 microns and collected in distilled water. Sections are placed in ammoniacal silver solution for 30 s, rinsed in 100% acetone and developed in a reducing solution at 75 degrees C. Sections are toned in 1% gold chloride solution and fixed in 50% sodium thiosulfate. After washing, the sections are dehydrated, cleared and mounted in the usual way for light microscopy.

Animals↗

PubMed1987

The hypothalamic magnocellular system in the domestic fowl. Study on semithin sections.

Neuronal characteristics and location of the neurosecretory, magnocellular, fuchsin-paraldehyde-positive (FA+) system of the fowl are described at the light-microscopic level on serial semithin sections. Three nuclei make up this system, the nucleus supraopticus, n. magnocellularis interstitialis and n. paraventricularis. These nuclei display magnocellular neurons, not showing a parvocellular component. The neurons of the three nuclei showed a scattered pattern of distribution and a dense surrounding neuropil. Groups formed by magnocellular neurons were found in the three nuclei and groups formed by one magnocellular and a parvocellular neurons were only found in the n. magnocellularis interstitialis and in the n. paraventricularis. The presence of neurons in apposition to blood vessels was frequent in the magnocellular FA+ system of the domestic fowl.

Animals↗

PubMed1986

A threedimensional reconstruction program for personal computers.

A reconstruction program is described for personal computers, permitting threedimensional image reconstructions from serial sections. This program also makes it possible to calculate the volume of structures from their twodimensional images in histological sections. In this paper we show a program written in BASIC and debugged on a Sharp MZ-700 personal computer, equipped with the Sharp MZ-1P01 plotter. The program is explained in detail and is easily adapted to run on any personal computer.

Computers↗