Accumulation Of Cytoplasmic Granules Research Articles

Diplopods as Soil Bioindicators of Toxicity After Application of Residues From Sewage Treatment Plants and Ethanol Industry.

Residues like sewage sludge and vinasse have been reused as agricultural fertilizers, but they also present a potential to contaminate soils. Diplopods have been considered excellent bioindicators of soil contamination. In the present study, Rhinocricus padbergi were used to assess toxicity in samples of sewage sludge, biosolids, and sugarcane vinasse. The behavioral analysis, mortality rate, and histological, histochemical, and ultrastructural analyses of the midgut of diplopods were the parameters evaluated. Behaviorally, some diplopods avoided burying themselves after 30 days in soil with biosolid or vinasse. Besides, certain residue combinations were able to cause death of all individuals between 60 and 90 days of exposure. The main tissue responses were significant brush border thickening, induction of epithelial renovation, clustering of hemocytes, accumulation of cytoplasmic granules in hepatic cells, hepatic cells with heteropycnotic nuclei, and cytoplasmic degradation. Alterations were observed at various levels among treatments with different samples and exposure times. Ultrastructural analysis revealed elongation of microvilli coated with a layer of an amorphous substance, resulting in a thicker brush border as observed in the histological analysis. After 30 days of exposure, animals showed an accumulation of spherocrystals in hepatic cells and high absorption of substances, based on the elongation of microvilli. Results obtained in the chemical analysis and the behaviors observed in diplopods suggest that animals processed the residues. Therefore, caution should be exercised in the disposal of these residues in agriculture.

Analysis of toxicity biomarkers of fullerene C₆₀ nanoparticles by confocal fluorescent microscopy.

The methods of laser confocal microscopy were employed to study the changes in rat target organs (iliac mucosa and liver) provoked by peroral administration of dispersion of nanosized (31 nm) multimolecular fullerene C60 particles in doses of 0.1, 1.0, and 10 mg/kg body weight over 92 days. The micropreparations were selectively stained with fluorescent dyes to mark the cell nuclei (DAPI), actin microfilaments (fluorescently labeled phalloidin), and the membrane proteins CD106, CD31, and claudins in tight junctions (fluorescently labeled monoclonal antibodies). In rats treated with fullerene in the examined doses, the iliac mucosa demonstrated normal morphology of the villi. There were no signs of inflammation and no alterations in the actin fi laments of cytoskeleton and in enterocytic tight junctions. The count of CD106(+) and CD31(+) cells did not change. The highest examined doses of fullerene (1 and 10 mg/kg body weight) increased population and modified distribution of hepatic CD106(+) cells. They also resulted in accumulation of cytoplasmic granules presumably identified as Kupffer macrophages without any signs of visible inflammation or necrotic areas. This phenomenon can reflect the early stages of toxic reaction being a sensitive bioindicator of the damage produced by administered fullerene C60 in the hepatic tissue.

Strict angiotensin blockade prevents the augmentation of intrarenal angiotensin II and podocyte abnormalities in type 2 diabetic rats with microalbuminuria

Beneficial effects of angiotensin II type 1 receptor blockers have been indicated for patients with diabetic nephropathy. We investigated the effects of an angiotensin II type 1 receptor blocker, telmisartan, on intrarenal angiotensin II levels and the progression of albuminuria or glomerular injury in type 2 diabetic Otsuka Long-Evans Tokushima Fatty rats with microalbuminuria. Otsuka Long-Evans Tokushima Fatty rats were randomly treated with telmisartan (10 mg/kg/day, orally), hydralazine (25 mg/kg/day in drinking water) or vehicle from the initiation of albuminuria (13 weeks old). At this age, Otsuka Long-Evans Tokushima Fatty rats showed low but detectable albuminuria (1.0 +/- 0.1 mg/day) and higher systolic blood pressure, postprandial blood glucose and kidney angiotensin II levels than age-matched nondiabetic Long-Evans Tokushima Otsuka rats. At 35 weeks of age, vehicle-treated Otsuka Long-Evans Tokushima Fatty rats did not show apparent glomerular injury or tubulointerstitial fibrosis but did exhibit severe albuminuria (72.6 +/- 5.9 mg/day) and accumulation of cytoplasmic granules containing albumin in podocytes. Otsuka Long-Evans Tokushima Fatty rats also showed higher systolic blood pressure, postprandial blood glucose, collagen gene expression, desmin staining (a marker of podocyte injury) and angiotensin II levels than Long-Evans Tokushima Otsuka rats. Treatment with telmisartan did not affect postprandial blood glucose but decreased systolic blood pressure, collagen gene expression, desmin staining and angiotensin II levels. Telmisartan also prevented the development of albuminuria (0.6 +/- 0.1 mg/day at 35 weeks old) and accumulation of cytoplasmic granules. Hydralazine treatment resulted in a similar reduction in systolic blood pressure and partially attenuated the albuminuria (35.4 +/- 1.8 mg/day at 35 weeks old) but did not affect the other parameters. The present results suggest the contribution of augmented intrarenal angiotensin II levels to the initiation and progression of albuminuria as well as podocyte abnormalities in type 2 diabetic rats. Angiotensin II blockade may inhibit the transition from microalbuminuria to overt nephropathy through prevention of intrarenal angiotensin II augmentation, independently of changes in blood pressure and glucose levels.

Morphology of the femoral glands in the lizard Ameiva ameiva (teiidae) and their possible role in semiochemical dispersion

Many lizards have epidermal glands in the cloacal or femoral region with semiochemical function related to sexual behavior and/or territorial demarcation. Externally, these glands are recognized as a row of pores, opening individually in the center of a modified scale. In many species the pores are used as systematic characters. They form a glandular cord or, in some species, a row of glandular beads below the dermis, and are connected to the exterior through the ducts, which continuously liberate a solid secretion. Dead cells, desquamated from the secretory epithelium, constitute the secretion, known as "a secretion plug." The present work focuses on the morphology of the femoral glands of the teiid lizard Ameiva ameiva, correlating it to the way in which the secretion is deposited in the environment. The results here obtained are compared to those available for other lizards and amphisbaenians. We observed that the diameter of the glandular pores did not show significant differences between males and females. The glands comprise germinative and secretory cells, which pass through at least three stages of differentiation, during which an accumulation of cytoplasmic granules, with a glycoprotein content, occurs. The cells eventually die and desquamate from the secretory epithelium, forming a secretory plug mostly constituted by juxtaposed nonfragmented secretory cells. Because of the arrangement of the rosette-like scales surrounding the femoral pores, we suggest that when the animal is in a resting position, with its femoral regions touching the ground, these scales may be involved in the breakage of their respective plugs, depositing tiny portions on the substrate. In this manner, it seems that the method for signal dispersion in this species involves specifically adapted structures and does not simply involve the chance breakage of the plug, as the gland secretes it. Signal dispersion must also be intimately associated with the animal's movement within its territory.

Responses of two different types of pituitary gonadotrophs of the loach, Misgurnus anguillicaudatus, to gonadectomy and to exogenous sex steroids

In the proximal pars distalis of the pituitary gland of the loach, Misgurnus anguillicaudatus, two basophilic cell types with different localities, staining properties, and cytological characteristics are discernible other than thyrotrophs and somatotrophs. Ultrastructural changes of these two types of basophils, termed the globular and the vesicular cells according to their ultrastructural features, were examined in loaches of both sexes which had been subjected to bilateral gonadectomy and to treatment with sex hormones during the late prespawning period. Complete gonadectomy stimulated the globular cells to show dilation of the rough endoplasmic reticulum and a decrease in the amount of cytoplasmic granules. The changes were less intense in males than in females 60 days after gonadectomy. The vesicular cells did not show evident alterations following ovariectomy in females but did respond to castration in males with an enlargement of the cytoplasmic vesicles characteristic of the cell type. After six injections of estradiol (50 μg/fish) to females during a month, the globular cells became atrophic with accumulation of cytoplasmic granules, while the vesicular cells exhibited rather slight changes of their activity including an activation of the Golgi apparatus. Similar administrations of testosterone (100 μ/fish) to males elicited regressive changes of both the globular and the vesicular cells, and shrinkage to a lamellar form of cytoplasmic vesicles in the latter cells is particularly notable. The results were discussed in terms of the possible existence of two distinct types of pituitary gonadotrophs in the loach, each of which may play a role at different stages of the sexual cycle of the fish of each sex.

The interrenal gland and ACTH and prolactin cells in the adenohypophysis of Monopterus and their roles in osmoregulations

The interrenal gland of the freshwater ricefield eel, Monopterus albus, consists of 3β-HSD-positive adrenocortical cell cords intermingled with groups of chromaffin cells; it lies in the haemopoietic tissues at the anterior tip of the head kidney and close to the posterior cardinal vein. Experimental studies using cortisol, metopirone, mammalian ACTH, and dexamethasone treatments show that ACTH and metopirone cause hypertrophy of the adrenocortical cells while cortisol and dexamethasone result in their atrophy; in the same experiments, the adenohypophyseal type-1 cells undergo hypertrophy in metopirone-treated animals but in the other three treatments there is cell regression and accumulation of cytoplasmic granules, showing that an endocrine feedback mechanism is in operation between the pituitary type-1 cells and the adrenocortical tissue. On the experimental evidence available, the adenohypophyseal type-1 cells in Monopterus are concerned mainly with adrenocorticotropic functions. Plasma electrolyte concentrations after the above treatments are also recorded, indicating an overall decrease in plasma sodium concentration after exogenous cortisol or ACTH administration. On the other hand, experiments involving administration of ovine-prolactin and reserpine, or alterations of the osmolarity and sodium concentration of the environment, show that prolactin is concerned with sodium and chloride conservation in this fish and that the pituitary type-2 cells in Monopterus are related to prolactin secretion. Thus the present report provides some experimental verification of the corticotropic and prolactin secreting roles, respectively, of the adenohypophyseal cell types-1 and -2 in Monopterus.

A study on the thyroid gland and the TSH cells in the pituitary of the ricefield eel, Monopterus albus

The thyroid gland of the ricefield eel, Monopterus albus, was located by histological studies and by radioactive iodine uptake technique in the anterior region of the head kidney and comprised follicles, which possessed à colloid-filled lumen lined by epithelial cells. The gland is not encapsulated but embedded in the haemopoietic tissue of the kidney. Treatment of the fish with ovine-TSH (NIH-TSH-S6) at a dosage of 1 USP unit for different lengths of time (12 hr to 3 days) stimulated the thyroid follicles to various degrees of response, from increase in cell height of follicular epithelium to overstimulation leading to rupture of the thyroid follicles. This treatment caused, at the same time, a marked regression in both cell size and nuclear size of the type 5 cells in the adenohypophysis, which have been identified in previous cytological and histochemical studies to be the “TSH” basophils, and accumulation of cytoplasmic granules were also observed in these type 5 cells. Fish treated with thiourea (0.15% solution) for 20 days were found to have their thyroid epithelial cells stimulated; the adenohypophyseal type 5 cells were also stimulated to increase in both cell and nuclear size with degranulation of cytoplasmic contents. The effects of thyroxine treatment (20 μg/l solution) for 20 days were exactly the opposite of the thiourea treatment in that the mean cell height of thyroid epithelium decreased and the adenohypophyseal type 5 cells regressed, accompanied by the accumulation of cytoplasmic granules. Other basophils in the adenohypophysis were also affected by these treatments but the responses were most characteristic and most obvious in the type 5 cells. In normal animals, the type 5 cells in the pituitary exhibited à seasonal cycle in activities which is probably more related to seasonal changes in general metabolism as the pattern of variation showed no sexual dimorphism. Results obtained in the present studies provided experimental verification that the type 5 adenohypophyseal cells are mainly related to the direct control of thyroid function and are hence TSH-secreting cells in Monopterus. Relationships of the type 5 cells with the thyroid and with the other basophils are also discussed.

A Study on the Relationship between Blood Pressure and Chromaffine Cells of the Adrenal Medulla after X-ray Irradiation

The present studies were undertaken to investigate the relationship between blood pressure and adrenal medullary cells (norepinephrinecontaining cells) in adult male rats after whole body X-ray irradiation (700 R.). 1. Both systolic and diastolic values of blood pressure elevated at 3, 24 and 48 hours after irradiation, but systolic pressure became lower than the normal level at 0.5 and 72 hours (p<0.01). 2. Pulse rate decreased at 3, 72 and 120 hours after irradiation (p<0.01). Although pulse rate showed tendency to decrease in 24 and 48 hours, it was not statistically significant. 3. Increase in number of norepinephrine-containing cells with marked accumulation of cytoplasmic granules was seen at 3, 12, 24 and 48 hours after irradiation (p<0.01). On the other hand, decrease in number of cytoplasmic granules associated with marked degeneration was observed at 72 and 120 hours. 4. These results indicated the positive correlation between blood pressure and morphological changes of norepinephrine-containing cells.