OBJECTIVE:In order to assess the proliferative changes induced by all-trans retinoic acid (RA) and retinol (ROL), we have carried out a study of the DNA content of basal and suprabasal keratinocytes after epicutaneous application on the rhino mouse.STUDY DESIGN:Skin sections were analyzed stereologically and cytophotometrically using the Feulgen technique. The diploid DNA value (2C) was obtained from hepatocyte nuclei of control animals. Whereas cells in phase G0-G1 will show a 2C content, cells during phase S and in phase G2-M will show DNA values ranging from 2C to 4C and 4C, respectively.RESULTS:Although epidermal thickness (ET) increased significantly in all treated animals, surface density only increased in animals treated with all-trans RA. Quantification of DNA content of basal keratinocytes showed reduction of 2C and 2C-4C populations with a commensurate increase in proportions of cells with 4C and > 4C in the animals treated with 0.025% all-trans RA and ROL. Suprabasal keratinocytes of mice treated with 0.025% all-trans showed a decrease of the 2C population and an increased proportion of cells with 4C. Whereas 0.025% all-trans RA induced an increase of both basal and suprabasal DNA indices, ROL enhanced only the basal DNA index significantly.CONCLUSION:Animals treated with 0.025% ROL showed a significant increase in the basal proliferative index (PI) while the suprabasal PI remained constant; treatment with 0.025% all-trans RA produced a significant increase of both basal and suprabasal PIs and parakeratotic hyperkeratosis probably due to incomplete differentiation.

Background: In a previous study of 26 patients with psoriasis we analyzed cytophotometrically the nuclear DNA content of the germinative compartment of involved and uninvolved skin by means of the Feulgen technique. These subjects were classified into three groups according to their DNA profile. Group 1 had a monomodal diploid profile, group 2 showed a significantly increased 2C-4C population, and group 3 demonstrated high proportions of 4C and hyperdiploid keratinocytes.Objective: Our purpose was to analyze clinical variables implicated in the development of psoriasis in reference to the three groups.Methods: Nuclear DNA content of each group by quantitative histochemical studies was analyzed and correlated with variables such as chronologic age, sex, age at onset, duration of flare during the study, stress, and the Koebner phenomenon.Results: No significant differences in DNA profile were observed in the involved epidermis among the clinical variables. The only differences in the uninvolved skin pertained to the duration of the flare, where a statistically significant difference was observed between groups 1 and 3 in the basal (p less than or equal to 0.0459) and suprabasal keratinocytes (p less than or equal to 0.06), and in the Koebner phenomenon, which was induced in all subjects (100%) in groups 2 and 3 and in only 44% of subjects in group 1.Conclusion: Uninvolved skin of patients with psoriasis should be included in analysis of the clinical behavior of the disease. Furthermore, the Koebner phenomenon is a good clinical indicator of the DNA profile of these subjects.

In this paper we present an analysis of the visual sector of the Thalamic Reticular Nucleus (TRN) from 3, 6, 18, 24 and 30 month old Wistar rats using stereological methods. The volume density (Vv), the number of neurones per surface unit (Na) and the neurone numerical density (Nv) showed a progressive decrease between the 3rd and the 24th months as the animals aged, whereas a significant increase was observed between the 24th and the 30th month, the period at which these rodents have fully entered old age.

We have studied the cytochrome oxidase activity and its pattern of distribution in the dorsal lateral geniculate nucleus of the rat during postnatal development. Between the 1st and the 8th postnatal days, the geniculate nucleus is seen to have a homogeneous enzymatic pattern with high neuronal density and moderately reactive neuropil. On the 15th postnatal day, different levels of neuronal enzymatic activity are found, and adult morphology is attained as of the 21st. The densitometric study has revealed that moderate and lightly reactive neurons are predominant between the 1st and the 8th postnatal days, whereas dark neurons are more numerous and optical density maximum on the 15th postnatal day. No variation in the enzymatic pattern was observed between the 21st and the 42nd days.

We have planned a stereological ultrastructural study of capillaries in the thyroid gland treated with IR laser radiation and quantified 1 day after the last treatment. Wistar rats, 50 days old, were irradiated with IR laser radiation. The rats were perfused with 2.5 percent glutaraldehyde in 0.1 M phosphate buffer (ph equals 7.4). The pieces obtained after sectioning the thyroid gland were placed immediately into the same fixative. A stereological study of the thyroid capillaries was carried out. This analysis revealed an increase of luminal area in irradiated capillaries.

The ultrastructural alterations of the chondrocytes in the growing cartilage after radiation by IR laser at a dose of 2 J/cm 2 are described. Twenty albino Wistar rats have been used. The radiation was carried out on the left knee of the animals. Consequently, the animals were killed, and as soon as the pieces had been obtained they were subjected to the conventional techniques of fixation and inclusion for electron microscopy. Their ER is scarcely developed with disrupted and dilated cisternae noting few secretory vesicles in relation to the control animals. Likewise, degenerative phenomena in the mitochondria membranes and the endomembrane system were observed, in the shape of myelin. In the chondrocytes of the contralateral knee, few alterations were noted in relation to the controls.

A quantitative immunohistochemical study of human spermatogenesis was performed using the 4D4 anti-proacrosin monoclonal antibody (mAb 4D4) as a marker of meiotic and post-meiotic germ cell differentiation. Cells from 15 testicular biopsies with normal spermatogenesis, 18 with slight and nine with marked hypospermatogenesis and six with maturation arrest were assigned to spermatogenic stages according to both nuclear maturation and proacrosin labelling patterns. The results showed that four spermatogenesis steps (mid- and late-pachytene primary spermatocytes, early and late spermatids) have to be separately considered for the classification of a given biopsy. Conversely, data from primary spermatocytes in the metaphase, anaphase and telophase stages and secondary spermatocytes did not show significant differences between biopsies. We conclude that: (1) slight hypospermatogenesis is due only to fewer cells entering meiosis, whereas in marked hypospermatogenesis there is also germ cell loss during the later meiotic steps and spermiogenesis; (2) the sloughing of germ cells from the epithelium could be of pathological significance; and (3) immunodetection with mAb 4D4 improves the assessment of spermatogenesis because it can label a protein expressed as early as meiotic prophase. In addition, mAb 4D4 labels a protein which is a marker of the Golgi complex allowing the detection of disturbances of cytoplasmic events during meiosis or spermiogenesis. Such an analysis is facilitated by mAb 4D4 labelling of paraffin-embedded sections.

We have examined the results obtained from the stereological ultraestructural study of follicular cells in thyroid glands treated with IR laser (904 nm). We studied 40 wistar rats exposed to radiation with doses of 46,80 J/cm2. They were sacrificed 1 and 180 days after the treatment. A stereological study of the volume and surface density was made in mitochondria, rER. Gogi complex and cytoplasmic granules. In the rats sacrificed 1 day after exposure to laser radiation, the thyrocited showed minimal morphological changes. In the rats sacrificed after a long period (180 days) the thyrocites showed a significant increase of volume and surface densities of rER, that may mean decreased capacity of the cells to synthesize thyroglobulin. Volume and surface densities of the citoplasmic granules experienced a significant increase.

The present histological and stereological studies are on thyroid glands of Wistar rats irradiated with an IR laser. The animals were exposed to total doses of 46,80 J/cm2, and sacrificed at 1, 40, and 180 days after the last treatment. A morphological and stereological study was made on follicular epithelium, follicle, stroma, and capillary. The laser beam produced an increase of follicular epithelial volume and hyperplasia of follicular cells in the animals sacrificed at 1, 40, and 180 days after the last treatment. Capillary dilation underwent a progressive decrease as time passed. It was higher in the animals sacrificed after 24 hours, then it decreased after 40 days and finally disappeared after 180 days.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

We carried out a quantitative study of the matrix and dermal papilla of the human hair follicle of the scalp, both normal and in various degrees of androgenetic alopecia. A stereological study showed the measured parameters to decrease with increase in the degree of alopecia, particularly as regards the total volume of the matrix and its papilla. The ratio of the two volumes increased by 30%, indicating a much more marked decrease in size of the papilla than in the matrix size. The number of cell nuclei in the matrix and the papilla of alopecic scalp was found to be 30% and 50% smaller, respectively, than those of normal scalp. Finally, a morphometric study revealed enlarged nuclei in the matrix and papilla, as shown by their increased areas, perimeters, and maximal diameters.

Twenty-one intradermal nevi were studied by morphometric methods in an attempt to morphologically characterize the two types of nevus cell--epithelioids, type A, and fusiforms, type C--and to quantify the differences between them. Morphometric parameters of the intradermal nevi were compared with similar parameters of melanocytes and melanoma cells so that the maturation rates of the nevi cells could be established and to see if the parameters might indicate the degree of malignancy. Superficial nevus cells were differentiated from deep cells by their larger size and larger nuclear area. Nuclear area appeared to have potential for differentiating benign from malignant tumors. Decrease in cellular area appeared to indicate maturation rather than atrophy. Melanoma cells were differentiated by their larger size. Cell nuclear perimeter appeared to have confirmatory value, while cell perimeter was inconclusive.

Nuclear and cytoplasmic dLGN neurons were investigated by cytophotometric measurements of RNA. This study has been carried out in rats from birth to adulthood. In order to quantify the RNA content a cytophotometer was used. Extinction mean values were obtained which indicated RNA concentrations per surface unit. The nuclear and cytoplasmic surface were calculated simultaneously and from the product of the mean extinction and the surface the RNA total content was calculated. Our results have suggested that the changes are age-related. From day 1 to day 21 the neuronal size and RNA content increase; this may somehow be involved with the differentiation process. Around post-natal day 21 neuronal maturation may begin, reaching its optimal phase around day 42, on which the RNA concentration per surface unit, surface neuronal content and RNA total content are stable.

The different types of neurons within the visual sector of the rat's thalamic reticular nucleus were studied, both in terms of their morphology and their histochemical activity. Neurons were classified according to their dendritic arrangement into bitufted and multipolar. On the basis of the somal shape, bitufted neurons were further subdivided into two types, triangular and fusiform, and multipolar neurons into stellate and ovoid. Bitufted neurons have moderate succinic dehydrogenase (SDH) activity, while multipolar neurons usually have high SDH activity. Finally, the location of neurons in the visual sector of the thalamic reticular nucleus was described.

The chronology of dLGN development was studied in the rat from birth to 90 days postnatal (dpn). Our results indicate the faster dLGN growth occurs from 1 dpn to 21 dpn. The neuronal number and density was calculated. No significant neuronal loss was detected in the period investigated but the present study shows evidence of an important decrease (of 75%) in the neuronal density between 7 dpn and 21 dpn. Immediately the study of neuronal sizes and shapes was undertaken. Approximately at 14 dpn the deep neurons get a size significantly bigger than the marginal neurons. Finally, the different neuronal sizes were used for determining the successive phases of the neuronal development.