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PubMed2000

Ultrastructural immunogold study on the various cell types of cultured pancreatic islets of adult rats.

Whereas several reports describing the ultrastructure of the intact pancreatic islets have been recorded, published experience with the ultrastructural integrity of the cultured pancreatic islets is limited. The present study was, therefore, undertaken to provide an ultrastructure identification of the different cells in the cultured islets of the adult rat pancreas, after marking their secretory granules with gold particles. Pancreatic islets were isolated from adult male Wistar rats by the intraductal perfusion of collagenase technique. The islets were cultured in RPMI-1640 medium for 3 days and processed for preparation of ultrathin sections. The sections were stained with the indirect immunogold technique for insulin, glucagon, somatostatin, and pancreatic polypeptide. Ultrastructural examination of the cultured islets clearly identified the presence of B, A, D and PP-cells, as indicated by the numerous gold particles concentrated predominantly over the secretory granules. The secretory granules of the various cell types of the cultured islets demonstrated several similarities as well as differences from the recorded results of the corresponding secretory granules of the intact islets. The differences probably reflect a deviation in the underlying mechanisms of synthesis, maturation and secretion of the different secretory products of the cells in the cultured islets as they adapt to the in vitro environment.

Animals↗
PubMed1975

Ultrastructural changes in human prepubertal prostatic epithelium grown in vitro.

Ultrastructural changes in the prepubertal human prostatic epithelium maintained in vitro are described and are compared with the ultrastructure of the same tissue before culture. In cultured cells, rough endoplasmic reticulum and Golgi complex are poorly represented and the latter also loses its polarity. Increase in cytoplasmic microfilaments is discussed in relation to possible vitamin A deficiency. Primary and secondary lysosomes, arising from autophagy and endocytosis, occur in large numbers as autophagosomes, myelin figures, residual bodies, and multivesicular bodies. Prostatic acid phosphatase activity, an important secondary sex characteristic, is influenced by sex hormones and malignancy; since this enzyme is lysosome-associated, special emphasis is placed on lysosomal changes. Some ultrastructural changes in rough endoplasmic reticulum, Golgi complex, and the lysosomal system are similar to those observed after castration. This study presents ultrastructure of cultured cells which form the basis for studies involving neoplastic transformation, aging, and hormonal manipulation using an in vitro model. This is necessitated by the absence of an in vivo animal model for prostatic neoplasia; hence studies on prostatic oncogenesis, and age-related phenomenon, must be done on cells in vitro. Significance of this study is enhanced by the fact that normal human prepubertal prostate has not been studied before and normal viable prostate is generally not available for investigations.

Acid Phosphatase↗
PubMed1975

Subcellular mechanisms of parathyroid hormone secretion: ultrastructural changes in response to calcium, vitamin A, vinblastine, and cytochalasin B.

The effects of various agents on the in vitro secretion of parathyroid hormone (PTH) were studied previously, using bovine glands. Low calcium, (0.75 mM), vitamin A (vit A), and cytochalasin B stimulated secretion, and high calcium (3.0 mM) and vinblastine (VB) inhibited secretion, whereas hydrocortisone and VB inhibited the vit A-induced PTH secretion. In order to define subcellular mechanisms of PTH release at the morphologic level, a semiquantitative analysis of ultrastructural characteristics has been made on the same tissue with the same agents. Low calcium increased convolutions of the intercellular membrane, the number of large type I secretory granules, phagolysosomes, lipoid vacuoles, and lamellae of endoplasmic reticulum. Vit A and cytochalasin B widened intercellular spaces and increased intercellular membranous interdigitations, the number of type I secretory granules, and phagolysosomes. Vit A also dilated Golgi membranes, and cytochalasin B also increased the number of small type II secretory granules and the margination of granules along the cell membrane. High calcium increased the number of phagolysosomes and crinophagic and lipoid vacuoles. VB decreased the number of microtubules and caused stacking of endoplasmic reticulum lamellae. VB or hydrocortisone diminished some of the ultrastructural effects of vit A. The common ultrastructural findings in response to stimulation of PTH secretion by low calcium, vit A, and cytochalasin B raise the possibility that these agents may facilitate PTH secretion through a common messenger or may directly interact with the cell membrane or with the secretion granule for phagolysosome (or both). Our findings are consistent with the role of VB as a microtubule disrupter, but also suggest that VB inhibits PTH secretion through other mechanisms involving the cell membrane and endoplasmic reticulum. Microtubules may facilitate basal PTH secretion and vit A-induced secretion; however, since VB does not inhibit low calcium-stimulated PTH secretion and, ultrastructurally, microtubules were not increased in the presence of low calcium, low calcium-stimulated secretion is not dependent upon microtubular function.

Animals↗
PubMed2000

[Protective effects of SMT on myocardial ultrastructure of ischemia reperfusion injury in heart of rat].

AIM: To Investigate the myocardial ultrastructure effects of SMT on the ischemia reperfusion injury (IRI) in the rat heart. METHODS: Eighteen Spraqua-Dawley rats were randomly divided into three groups: ischemia reperfusion group (IR), subjected to 60 min of o-cclusion and 20 min of reperfusion of the anterior descending branch of left coronary artery; IR + SMT group (SMT), given the selective iNOS inhibitor S-methylisothiourea sulfate (SMT, 5 mg/kg, i.v.) before reperfusion; control group (C), didn't occlude coronary artery after exposing heart and observed 80 min. Electrocardiogram (ECG) was recorded. Nitrite and nitrate content were measured in myocardium and blood serum. The changes of myocardial ultrastructure were observed with electron microscope. RESULTS: Ischemia reperfusion induced ST segment elevation and T waves inversion or tallness in ECG, damaged myocardial ultrastructure, increased nitrite and nitrate content in myocardium and blood serum after IR compared with before IR(P < 0.01). Administration of SMT improved the changes of ECG and the injury of myocardial ultrastructure. Nitrite and nitrate content of myocardium were lower than IR group (P < 0.05). The change of nitrite and nitrate level of blood serum in SMT group was nearly in C group. CONCLUSION: SMT can prevent myocardium injury from reperfusion following ischemia.

Animals↗
PubMed2001

Ultrastructure and composition of asteroid bodies.

PURPOSE: Asteroid hyalosis is a disease of the vitreous, characterized by brilliant reflecting particles, termed asteroid bodies, which are surrounded by a tightly adhering network of fibrils. The composition and mode of formation of asteroid bodies is not yet understood in detail. The purpose of this study was to investigate the ultrastructure of asteroid bodies and to identify the intrinsic inorganic and organic components that contribute to the nature and development of asteroid bodies. METHODS: Electron energy loss spectroscopy and energy-filtered transmission electron microscopy were used for the elemental analysis of asteroid bodies. The ultrastructural localization of glycosaminoglycans was investigated, using lectin and antibody conjugates in conjunction with transmission electron microscopy and epifluorescence microscopy. Anionic sites of glycosaminoglycans were detected with 15 nm cationic colloidal gold at low pH, applied as a postembedding technique. Ultrastructural details of asteroid bodies were documented using fast Fourier transform analysis of zero-loss filtered images. RESULTS: Element mapping of asteroid bodies by electron spectroscopic imaging revealed a homogeneous distribution of calcium, phosphorus, and oxygen. The electron energy loss spectra of these elements showed details similar to those found for hydroxyapatite. Additionally, high contrast and sensitivity against a calcium-specific chelator highlighted the crystalline, apatite-like nature of asteroid bodies. Immunofluorescence microscopy revealed the presence of chondroitin-6-sulfate at the periphery of asteroid bodies, which is in agreement with the ultrastructural colocalization of anionic sites. Fast Fourier transform analysis revealed that each 7-nm periodicity of asteroid lamellar stacks is divided by a fine, parallel-oriented line, separating each 7-nm layer into two halves of 3.5-nm thickness. Carbohydrates specific for hyaluronic acid were observed by lectin-gold labeling to be part of the inner matrix of asteroid bodies. CONCLUSIONS: The results of this study demonstrate the structural and elemental similarity of asteroid bodies with hydroxyapatite. Proteoglycans and their glycosaminoglycan side chains are implicated in playing a role in regulating the biomineralization process.

Aged↗
PubMed2000

[Effect of Weikangfu granule on ultrastructure of gastric mucosa in patients of precancerosis with spleen deficiency syndrome].

OBJECTIVE: To observe the effect of Weikangfu Granule (WKFG) on the ultrastructure of gastric mucosa. METHODS: WKFG was used to treat 61 patients with gastric mucosa intestinal metaplasia or atypical proliferation, and histopathological and ultrastructural examination on gastric mucosa of antral region obtained through gastroscopy were conducted before and after treatment. RESULTS: After treatment, the histopathology and intestinal metaplasia subset of antral focal region, and the background lesion in ultrastructure of the mucosa in the nonfocal region were all improved in the 4 groups, The effects of Spleen-Qi Deficiency syndrome group and Spleen-Yang Deficiency group were superior to Ying-Deficiency group as well as Spleen-Deficiency and Qi-Stagnation group (P < 0.05, P < 0.01), and approached to those in the healthy control group. CONCLUSION: WKFG improves the quantitative balance of internal bioactive substances to maintain the homeostasis, promotes the ultrastructural normalization of mucosa so as to cure the clinical symptoms and reverse the intestinal metaplasia and atypical proliferation of mucosa.

Adult↗
PubMed2001

[Ultrastructural change of rabbit lens epithelial cells induced by low power level microwave radiation].

OBJECTIVE: To study the ultrastructural change of rabbit lens epithelial cells with transmission electron microscope and to observe whether low power level microwave can induce the injury of rabbit lens. METHODS: Eight rabbit eyes were exposed to 10 mW/cm(2) low power level microwave radiation for 30 hours. Transmission electron microscope was used to observe the ultrastructural changes of the lens epithelial cells. The other eye was served as self-control. RESULTS: The ultrastructure of exposed lens epithelial cells changed apparently. The characteristic apoptosis cell morphological changes, such as small cell size, the decreased number of mitochondria, balloon-shaped mitochondria, etc can be seen. No obvious changes can be found in the protected self-control eyes. CONCLUSIONS: The low power level microwave (10 mW/cm(2)) can induce the ultrastructural changes of rabbit lens epithelial cells, this may be the appearance of early irreversible microwave radiation injury. In regard to the pathogenic mechanism, it is necessary to perform further investigations.

Animals↗
PubMed1999

[Protective effect of endothelin receptor subtype A antagonist BQ610 on the ultrastructure of acute ischemic myocardium in cats].

OBJECTIVE: To observe the effects of endothelin receptor subtype A antagonist BQ610 on acute ischemic myocardial injury by electronic microscopy to study whether endogenous endothelin is involved in the pathogenesis of acute myocardial ischemia. METHODS: Acute myocardial ischemia was induced by ligation of the left anterior descending coronary artery (LAD) in 12 cats, and BQ610 was immediately injected into the occluded LAD. Controls received normal saline (NS) injection. The ultrastructure of ischemic myocardium and non-ischemic myocardium were observed 30 min after LAD ligation. RESULTS: As compared wtih NS controls, BQ610 significantly protected the acute ischemic myocardium from ultrastructural injury, including cardiac muscle fiber swelling, myofibril disorganization and breakdown, mitochondrial swelling and endothelial swelling. In general, the non-ischemic myocardial ultrastructure was normal. CONCLUSIONS: The results indicate that endogenous endothelin, through endothelin receptor subtype A, plays an important role in ultrastructure injury of acute ischemic myocardium in cats.

Acute Disease↗
PubMed2002

Does ultrastructural morphology of human detrusor smooth muscle cells characterize acute urinary retention?

PURPOSE: Acute urinary retention is relatively rare in otherwise healthy men. The condition may be attributable to a combination of obstruction and detrusor hypocontractility. We determined whether acute or chronic urinary retention is accompanied by characteristic ultrastructural features in bladder detrusor smooth muscle cells and whether any of these ultrastructural features may be useful for classifying these conditions. MATERIALS AND METHODS: Bladder biopsies of 15 men, including 13 in acute and 2 in chronic urinary retention, and 6 controls were examined by transmission electron microscopy. They were semiquantitatively and morphometrically analyzed for degenerative changes, cellular hypertrophy, variations in intercellular distances, abnormal cell junctions and configurations, and intracellular changes. RESULTS: No significant ultrastructural features were noted in the detrusor muscle of patients in acute urinary retention compared with controls. CONCLUSIONS: We cannot confirm the reports of others that characteristic ultrastructural features in smooth muscle cells accompany bladder outlet obstruction and detrusor hypocontractility.

Acute Disease↗
PubMed1975

Correlations between histochemical and ultrastructural studies of diseased muscle.

The acceptance of a syndrome as a distinct nosological entity depends upon our ability to demonstrate that it consistent genetic, pathological and biochemical abnormalities. During the past two decades the application of enzyme histochemistry and electronmicroscopy to the study of biopsy muscle from patients from a variety of ill-defined neuromuscular disorders has enabled us to classify them with much greater precision. This approach, together with increasingly sophisticated electrophysiological techniques, has lead to a much clearer separation of neurogenic and primarily myopathic disorders with a consequent shrinkage in the category of pure muscular dystrophy. Perhaps the most useful application of morphological techniques alone has been in the field of congenital and metabolic myopathies, the histochemical and ultrastructural abnormalities in some cases providing valuable clues to the pathogenesis or even the aetiology of the underlying disease process. This applies particularly to the various glycogen storage diseases affecting skeletal muscle, disorders in which there appear to be structural and functional abnormalities of muscle mitochondria or in which excessive amounts of lipid are stored in muscle fibres. In this communication the histochemical and ultrastructural characteristics of these diseases will be detailed, their possible significance discussed and the relative non-specificity of some of these morphological abnormalities will be noted. A comment will be made on the frequency with which simple Type II fibre atrophy (as demonstrated by the myofibrillar ATPase preparation) may be accompanied by gross and bizarre ultrastructural abnormalities, e.g. in the myopathy accompanying chronic renal failure. Such inconsistencies underline the fact that it is not always possible to demonstrate a close correlation between histochemical and ultrastructural abnormalities in muscle disease. However, it should be emphasized that the combined approach is essential to the rational morphological study of these disorders.

Biopsy↗
PubMed2002

[Ultrastructural features of cultured rat cortical astrocytes with stretch-induced injury].

OBJECTIVE: To investigate the changes of ultrastructural features of cultured rat cortical astrocytes after stretch-induced injury. METHODS: Rat cortical astrocytes isolated from 1- to 2-day-old rats were cultured till confluency, and then plated in tissue culture wells with flexible silastic bottom after purification. A computer-controlled device was used to produce stretch-induced injury in the astrocytes with the imposed pressure of 50, 150, and 250 kPa respectively, followed by observation of the ultrastructural changes in the astrocytes with light and electron microscopy. RESULTS: Obvious ultrastructural destruction of the astrocytes occurred when the imposed stretch pressure was 50 kPa, and scanning electron microscopy demonstrated increased intercellular space and laceration of the cell body and its processes. Transmission electron microscopy revealed mitochondria swelling 1 h after stretch-induced injury and 6 h after the injury, vacuolar degeneration of the mitochondria occurred. Increased stretch pressure caused further decrease in the amount of glial filaments and densification of astrocytes. CONCLUSIONS: Stress, even at a relatively small scale, can cause disruption of intercellular juncture and ultrastructural change of the cultured astrocyte, which may be related with extensive brain edema after traumatic brain injury.

Animals↗
PubMed2000

[Relationship between the ultrastructural characteristic of coal dust and its toxicity].

To study the relationship between the ultrastructural characteristic of coal dust and its toxicity, we compared two types of coal dusts which damaged alveolar macrophages(AMs) concerning with the coal dusts ultrastructural characteristic by using microscopy and biochemical techniques. The results showed that coal dusts damaged not only AMs plasma and lysosomal enzymes but also in ultrastructure. The coal dust in Nanpiao mine had a sharp form, fragile texture and a structure putting in order. It was concluded that: (1) the toxicity of coal dust in Nanpiao mine was higher than in Kailuan mine and which was related to the ultrastructural feature of the coal dusts; (2) the AMs injury degree by coal dusts was more and more serious with the duration of exposure to coal dusts.

Animals↗
PubMed2000

Application of Transmission Electron Microscopy for Analysis of Ultrastructural Organization of Circulating Immune Complexes in Patients with Typhoid Fever and Chronic Carriers of Salmonella typhi.

Transmission electron microscopy was used to study the ultrastructural organization of circulating immune complexes (CIC), isolated from patients with typhoid fever in the different periods of acute infectious process (febrile period, period of an early and late reconvalescence), relapse and from acute and chronic carriers of Salmonella typhi in the period of pathogen excreting. It has been shown that preparations of CIC from healthy donors consisted of amorphous mean electron density material, including a cell-like detritus. At acute and chronic infectious process there were bacterial cells in a structure of the CIC. Depending on the period of disease, bacteria had different ultrastructural organization in the CIC. In the febrile period, in the period of an early reconvalescence and in the period of formation of acute carriage of S. typhi, and also in relapse, bacteria had a typical structure, with reference to gram-negative microorganisms. In the period of formation of acute and chronic carriers of S. typhi, in a period of excretion of S. typhi, bacteria in the CIC had ultrastructural organization, relevant to the forms of bacteria with a defective cell wall. Immunocytochemistry research made with the purpose of visualization the O-antigen of S. typhi in bacteria has demonstrated positive immunolabeling on the O-antigen in the bacterial forms and forms with a defective cell wall, and on amorphous mean electron density material. The analysis of ultrastructural organization of the circulating immune complexes and immunolabeling on the O-antigen of S. typhi have allowed to conclude that S. typhi, both typical bacterial form, and the forms with a defective cell wall were the main structural component of circulating immune complexes in acute and chronic forms of infectious process.

Journal Article↗
PubMedDate not supplied

[Ultrastructure of muscle spindles (Mechanoreceptors) of Rat m. soleus after support unloading and its combination with hypergravity].

We used electron microscopy to evaluate the effect of support unloading of m. soleus in adult Wistar rats (restrained in an antiorthostatic posture for 23-24 h/day within 24 days) on the ultrastructure of the intrafusal fibers and motor neuromuscular junctions of the muscle spindles, as well as the efficiency of intermittent hypergravity (+2Gz; 1 h/day for 19 days in a centrifuge in hypokinetic cages) as a countermeasure used in conditions of support unloading of this muscle. In the absence of support on the hind limbs, most of intrafusal fibers of m. soleus preserved the typical ultrastructure, while the axon terminals of the neuromuscular junctions accumulated a lot of synaptic vesicles (including large vesicles); the coated vesicles were absent due to unloading of the muscle and its muscle spindles (no contractions of the intrafusal fibers). A short-term effects of hypergravity at the background of support unloading of m. soleus mostly induced static loading of the muscle inducing different responses of the intrafusal fibers in different regions of the muscle spindles: local lysis of myofilaments was observed in single intrafusal fibers of the equatorial and intracapsular motor regions, while myofibrils remained intact in most fibers in the intra- and extracapsular regions of the spindles. The revealed adaptive response of the intrafusal fibers is, on the one hand, due to their specific innervation and ultrastructure and, on the other hand, to positive effect of hypergravity on the motor and extracapsular regions of the muscle spindles. Hypergravity decreased the number of synaptic vesicles and induced appearance of the coated vesicles in the axon terminals of the neuromuscular junctions of the intrafusal fibers in the animals restrained in an antiorthostatic posture (support unloading of m. soleus), which is due to increased functional load of the muscle. The ultrastructure of the muscle fibers adequately reflected the functional status of the postural m. soleus both during support unloading and support unloading combined with hypergravity load.

Actin Cytoskeleton↗
PubMed2003

[The significance of zinc for contractility of smooth muscles and ultrastructure of their microfilaments in case of hypodynamic stress].

The aim of the study was to investigate the significance of zinc (added to food of the rabbits) for contractility of smooth muscles (effected by acetylcholine) and ultrastructure of their microfilaments in case of hypodynamic stress. Hypodynamic stress of 48-day duration was provoked for Chinchilla rabbits (n=20) by placing them in metal hutches. Every day (48 days) 10 rabbits, which had intervention received doses of zinc 0.3 mg/kg body wt (in form of zinc acetate). The rabbits (n=10) of the control group, which had no intervention were kept in vivarium conditions. The relaxation of smooth muscles from thoracic aorta as mediated by acetylcholine at a concentration from 10(-8) mol/l to 10(-4) mol/l was detected by means of a 6MXIC mechanotron in isometric regime. Response was expressed as the percentage of relaxation to prostaglandin F(2alpha) (10(-5) mol/l)-induced precontraction. The ultrastructure of the microfilaments of smooth muscles was evaluated by electron microscopy "Philips-300". In rabbits that received no zinc the relaxation of smooth muscles under the influence of acetylcholine was significantly lower than in rabbits that received zinc and lower in control rabbits. Also in rabbits without zinc supplement the investigation of ultrastructure of microfilaments revealed their damage (such change as irregular formation, drop out in flakes, microfilaments becoming shorter and thicker). In rabbits receiving zinc ultrastructure of microfilaments did not change.

Acetylcholine↗
PubMed2003

Cellular viability and ultrastructure of stented, antibiotic sterilized and cryopreserved sheep biological valves implanted for one year in tricuspid position.

UNLABELLED: The aim of the study was an evaluation of viability and damage of biological cells sterilized with antibiotics and cryopreserved a year after the implantation. Sheep antibiotic sterilised and cryopreserved biological valves were implanted in tricuspid position in young sheeps for one-year period. After this time the valves removed and studied morphologically. The control group consisted of 7 intact valves, the comparative group, so called group of valves after the processing antibiotic sterilization and cryopreservation consisted of 7 valves after mentioned procedures. Histologic investigations were based on paraffin sections of formalin-fixed valve cusps, stained with H&E and Masson trichrome. Valve viability was assessed using intravital staining with fluoresceine diacetate, whereas damaged cells were visualized by intravital staining with neutral red. Additionally, the ultrastructural studies were performed. The viability and ultrastructural results were compared with the pathologic process in the valve. CONCLUSIONS: 1. preliminary preparation with antibiotic sterilisation and cryopresrevation induces valve leaflet oedema and degenerative ultrastructural processes, colliquative cell necrosis and apoptotic morphology of a part of valve cells; 2. cryopreserved and antibiotic sterilised pulmonary valve after one-year implantation behaves lining cells, but ultrastructural changes indicates many degenerative phenomena in smaller degree than after preparation, sterilization and cryopreservation. Histopathologically the degenerative changes were prevalent.

Animals↗
PubMedDate not supplied

Cytomorphological, ultrastructural and immunological particularities of the synovial fluid in seronegative rheumatoid arthritis.

Our studies on the cytomorphological and ultrastructural analysis of 15 Synovial Fluid (SF) samples from patients diagnosed with seronegative Rheumatoid Arthritis (RA) and 10 SF from patients with Hydroarthrosis considered as controls were carried out. By cytomorphological studies we determined the cellularity, ragocytosis and synoviocytogram. SF in seronegative RA is characterized by leucocytosis (7,656/mm3) with polynucleosis (65.38%) and ragocytosis (59.27%) versus hydroarthrosis SF defined morphologically by lymphocytosis (47%). Degenerative forms of ragocyte-like polymorphonuclears (PMN) cells, individualized by an ultrastructural alteration less evident than recorded in seropositive Rheumatoid Arthritis (RA), associated with a remarkable capacity of endocytosis. The ultrastructural alterations, immune complexes (CIC), the immunoglobulins (MG) and the anticollagen II antibodies, suggest the early implication of these immune parameters in etiopathogenesis. The corroboration of the cytomorphological, ultrastructural and immunological data allows the profound study of the etiopathogenic mechanism and may represent a paraclinical criterion for differentiated seronegative RA field.

Antigen-Antibody Complex↗
PubMed1992

The toxic effects of combined exposure to toluene and m-xylene in animals. IV. Liver ultrastructure after subchronic inhalatory exposure.

The effects of combined inhalatory exposure to m-xylene and toluene on the rat hepatocytes were investigated. Limited proliferation of smooth endoplasmic reticulum and increase of the number of lysosomes were observed in hepatocytes after 3-months of single exposure to 1000 ppm of m-xylene and toluene. Moreover, mitochondria increased in most of hepatocytes. After combined exposure to mixture of m-xylene and toluene at concentrations of 500 + 500 ppm, respectively, the types of ultrastructural changes in hepatocytes followed the pattern observed after exposure of each of the single organic solvent. However, proliferation of the smooth endoplasmic reticulum was more eminent. The hepatocytes ultrastructure of rats exposed to 100 ppm of m-xylene and toluene for 6 months were similar to that observed in rats exposed to 1000 ppm of m-xylene for 3 months. In rats exposed to a mixture of m-xylene and toluene for 6 months, the ultrastructural changes in hepatocytes were a combination of those observed after a single exposure to each of the organic solvent. It may be concluded that changes in the hepatocytes ultrastructure were an adaptive rather than a toxic effect. Because in the case of combined exposures the doses were half of those used in single exposures, the additive effect on the proliferation of smooth endoplasmic reticulum was observed in the rat liver after combined exposure to toluene and m-xylene using electron microscopy.

Animals↗