Morphometry and autoradiography of early hypertrophic changes in the ventricular myocardium of adult rat: an electron microscopic study.

The ultrastructural composition of left ventricular myocardium and myocytes has been investigated at 20 hours after the surgical production of a subdiaphragmatic aortic stenosis in the adult rat. Morphometric analysis shows a 20% increase in the size of myocytes resulting principally from a 36% increase in mitochondrial volume and a 78% increase in the volumes occupied by smooth endoplasmic reticulum and matrix. Myofibrillar volume is increased only 4%. Measurements of the size and shape of individual mitochondria indicate that the augmentation of this compartment is wholly accountable by the enlargement of preexisting mitochondria. Quantitative autoradiographic analysis following a 2-hour pulse labeling with 3H-leucine shows that the rate of incorporation of newly synthesized proteins is practically uniform throughout all structural components of the sarcoplasm 18 to 20 hours after aortic banding. The conclusion is reached that this interval of hypertrophic response is a transition period characterized by an increasing rate of synthesis of contractile proteins overtaking a previously greater rate of mitochondrial synthesis.     

Medroxyprogesterone induced changes in rat liver. A light and electron microscopic study

Medroxyprogesterone acetate (MPA) induced morphological alterations in the normal female rat liver and after carbon tetrachloride exposure were assessed by light and electron microscopy and morphometry. Administration of MPA increased the smooth endoplasmic reticulum (SER) in normal rat. Carbon tetrachloride, injected intraperitoneally for four weeks, caused fatty accumulation, enlargement of the cell nucleus and decrease of the rough endoplasmic reticulum (RER) and increase of the SER. After one week of recovery, without treatment, the fatty infiltration and the SER membranes decreased and the RER increased. MPA, following injury, induced a decrease in the fatty accumulation and mitochondrial volume density and the hepatocyte nuclear and cytoplasm size normalized. The SER membrane volume density increased and the surface density decreased, the RER membrane volume density increased while the surface density did not alter significantly. The volume densities of the mitochondria and the peroxisomes decreased in the MPA treated CCl4 exposed groups. The results demonstrate that MPA induces a proliferation of the SER in normal rat liver and after hepatic injury the compound has a beneficial effect on the regeneration.     

Stereological analysis of the otic ganglia in adult rat: light microscopic study

Quantifications in parasympathetic ganglia are not available in literature. The otic ganglia of 9 Wistar rats were studied (thick and semi-thin sections) in order to determine the following quantitative data: ganglionic volume (GV), neuronal volume density (Vv), neuronal cellular surface per cell volume (Sv), and neuronal numerical density (Nv). The results showed (mean +/- SD): GV = 0.31 +/- 0.05 mm3, Vv = 39.62 +/- 12.25%, Sv = 0.169 +/- 0.056 microns-1 and Nv = 3.84 x 10(-5) +/- 1.69 x 10(-5) microns-3. These determinations provide a basis for comparisons of parasympathetic with sympathetic ganglia.     

Age-related alterations in the lacrimal gland of adult albino rat: A light and electron microscopic study

BackgroundAge related changes in the lacrimal gland are associated with alterations in the structural organization and functional response in the gland of diverse mammalian species. Dry eye syndrome is one of the most common ocular problems in the world especially in old age. It results when the lacrimal gland fails to secrete proteins and fluid in sufficient quantity or appropriate composition.Aim of the workThe present study is designed to demonstrate the influence of aging on the structure of the lacrimal gland of albino rat and to provide a morphological basis to explain the pathogenesis of the dry eye syndrome with ageing. It also aims to carry out a comparative analysis of age-dependent changes in male and female rats and to address how the lacrimal gland ages in each sex.Material and MethodsEighty albino rats were used in this study. The animals were divided into two age groups, young adult and senile. Tear secretion was measured using a modified Schirmer test. Corneal impression cytology of the anesthetized rats was done. The glands were subjected to gross morphologic examination, microscopic examination using H&E, PAS, Masson's trichrome and Giemsa stains. Electron microscopic examination was done in addition to quantitative histomorphometric estimations included acinar density, ductal count and mast cell count.ResultsLight microscopic examination of the lacimal glands of the senile rats revealed different pathological changes. These included acinar, ductal as well as stromal changes. Electron microscope examination of the lacrimal gland of the senile group showed a decrease in the electron dense secretory vesicles, mitochondrial swelling and lipofuscin-like inclusions were frequently seen in the cytoplasm of acinar cells in senile rats.ConclusionThe structural changes in the lacrimal glands of senile rats were associated with reduction in tear secretion as well as alterations in corneal epithelium. Gender difference in lacrimal gland structure was recorded.     

Age-related changes of dopamine receptors in the rat hippocampus: a light microscope autoradiography study

Hippocampus is a brain region involved in learning and memory and is particularly sensitive to ageing. It is supplied with a dopaminergic innervation arising from the midbrain, which is part of the mesolimbic dopaminergic pathway. Dysfunction of the dopaminergic mesolimbic system is probably involved in the pathophysiology of psychosis and behavioural disturbances occurring in the elderly. The present study was designed to assess the density and localisation of dopamine D1- and D2-like receptor subtypes in the hippocampus of male Sprague-Dawley rats aged 3 months (young), 12 months (adult) and 24 months (old). Dopamine D1-like receptors, labelled by [3H]-SCH 23390, in young rats displayed a dentate gyrus-CA1 subfield gradient. The expression was increased in the cell body of dentate gyrus, CA4 and CA3 subfield of old rats compared to younger cohorts, as well as in the neuropil of dentate gyrus. A decreased density of dopamine D1-like receptors was found in the stratum oriens of CA1 and CA3 subfields. Dopamine D2-like receptors, labelled using [3H]-spiperone as radioligand, were expressed rather homogeneously throughout different subfields of the hippocampus. In old rats, the density of dopamine D2-like receptors was decreased in the dentate gyrus, unchanged in the CA4 and CA1 subfields and increased in the CA3 subfield. The above results indicate the occurrence of inhomogeneous changes in the density of dopamine D1- and D2-like receptors in specific portions of hippocampus of old rats. These findings support the hypothesis of an involvement of dopaminergic system in behavioural abnormalities or psychosis occurring in ageing.     

Endothelial cell changes in acute hepatitis. A light and electron microscopic study

Hepatic endothelial cells were studied by light and electron microscopy in 48 patients with acute hepatitis due to virus infection or drug idiosyncrasy. Light microscopy revealed cell swelling and appearance of dense refractile intracytoplasmic granules staining with the amylase PAS reaction and for iron by Perls' method. They were orcein-negative. These cells, regarded as 'activated' endothelial cells, were found throughout the parenchyma, especially in the classical form of acute hepatitis. In acute hepatitis with bridging, panacinar or periportal necrosis, activated endothelial cells were prominent in the necrotic areas. They were constantly seen lining newly formed capillaries in these sites. By electron microscopy, the intracytoplasmic granules had the characteristics of primary or secondary siderosomes. In areas of capillarization, basement membrane material was seen on the aspect of the activated cells facing the space of Disse. Activated endothelial cells may play a part in protecting hepatocytes from injury.     

The distribution of ganglion cells in the posterior cricoarytenoid muscle of the normal adult rat. A light and electron microscopic study

We employed by light and electron microscopy to examine the innervation of the posterior cricoarytenoid muscle of the adult rat. The laryngeal nerve was found to often bifurcate into two different bundles. One contained large myelinated (motor) nerve fibers, which were located along the frontal (ventral) muscle surface and entered the muscle at its middle portion to form neuromuscular contacts with individual muscle fibers. The other nerve bundle consisting of clustered ganglion cells (20-30 microm in diameter) and their associated nonmyelinated and small-sized myelinated nerve fibers were mainly found on the dorsal side of the muscle and often ran along the peripheral clefts or depressions of the muscle surface. The nerve bundle often extended side branches, which entered the muscle to be distributed among muscle fibers and near arterioles. Some ganglion cells are considered to enter the muscle, accompanied by branched nerves. Intramuscular ganglion cells and their associated nerve fibers examined by electron microscopy were similar in fine structure to perimuscular ganglion cells and their associated nerve fibers. Nerve fibers contained abundant clear synaptic vesicles which were cholinergic in nature, and often formed synapses with both neighboring axons and the cell body of the ganglion cells. These findings suggest that, in the rat posterior cricoarytenoid muscle, perimuscular and intramuscular ganglion cells exist and may be involved in innervating and contracting smooth muscle cells of the arterioles, thus regulating the blood flow or intravascular pressure.     

The localisation of urocortin in the adult rat cerebellum: a light and electron microscopic study

Light and electron microscopic immunocytochemistry was used to identify the cellular and subcellular localisation of urocortin in the adult rat cerebellum. Urocortin immunoreactivity (UCN-ir) was visualised throughout the cerebellum, yet predominated in the posterior vermal lobules, especially lobules IX and X, the flocculus, paraflocculus and deep cerebellar nuclei. Cortical immunoreactivity was most evident in the Purkinje cell layer and molecular layer. Reaction product, though sparse, was found in the somata of Purkinje cells, primarily in the region of the Golgi apparatus. Purkinje cell dendritic UCN-ir was compartmentalised, with it being prevalent in proximal regions especially where climbing fibres synapsed, yet absent in distal regions where parallel fibres synapsed. In the Purkinje cell layer, the labelling was also contained in axonal terminals, synapsing directly on Purkinje cell somata. These were identified as axon terminals of basket cells based on their morphology. Terminals of stellate cells in the upper molecular layer also expressed the peptide. Whilst somata of inferior olivary neurones showed intense immunoreactivity, axonal labelling was indistinct, with only the terminals of climbing fibres containing reaction product. UCN-ir in the mossy fibre-parallel fibre system was restricted to mossy fibre rosettes of mainly posterior lobules and the varicose terminals of parallel fibres. Furthermore, labelling also was prevalent in glial perikarya and their sheaths.The current study shows, firstly, that urocortin enjoys a close ligand-receptor symmetry in the cerebellum, probably to a greater degree than corticotropin-releasing factor since corticotropin-releasing factor itself is found exclusively in the two major cerebellar afferent systems. Its congregation in excitatory and inhibitory axonal terminals suggests a significant degree of participation in the synaptic milieu, perhaps in the capacity as a neurotransmitter or effecting the release of co-localised neurotransmitters. Finally, its unique distribution in the Purkinje cell dendrite might serve as an anatomical marker of discrete populations of dendritic spines.     

Autolytic changes in the rat adenohypophysis. A histologic, immunocytologic and electron microscopic study.

Thirty-nine adult female Long Evans rats were decapitated and the heads stored at room temperature. The pituitaries were removed at intervals from 30 minutes to seven days, fixed, embedded and studied by histology, immunocytology and electron microscopy. Histologically, changes were noticeable after two hours postmortem. Immunoperoxidase staining showed postivity for growth hormone, prolactin, FSH, LH and TSH up to seven days after sacrifice, appearing even stronger in the advanced stages of autolysis. Fine structural alterations were evident at 30 minutes and more conspicuous later. Changes included dilation, partial degranulation and whorl formation of RER, swelling of Golgi complexes and mitochondria, chromatin clumping, lysis, rhexis and pyknosis of nuclei, cytosegresome formation and disruption of cell membranes. Secretory granules remained well preserved throughout, although some exhibited fusion or reduced electron density. Dilation of capillaries with accumulation of erythrocytes, platelets and fibrin fibers were prominent findings. The severity of changes varied considerably from cell to cell indicating that the rate of autolysis is not the same among different cell types and is possibly affected by the actual functional state of the cell. It appears that increased membrane permeability and disruption of plasmalemma represent important steps in the autolytic process.     

Myocardiac changes in experimental renal failure--a light and electron microscopic study.

The experiments we described in this paper demonstrated that the myocardiac lesions without hypertension could be produced by renal failure in rabbits; after this experimental renal failure, increase in blood urea nitrogen and various functional and morphological changes suggestive of heart lesions appeared. The main structural changes in the heart were cellular edema with dilatation of the sarcotubular system, destructive changes of the mitochondria and contractile elements, and coagulative degeneration. These myocardiac lesions are induced by renal failure, and are probably caused by electrolyte imbalance, metabolic disorder, and/or hemodynamic abnormality rather than by hypertensive or toxic factors.     

Morphologic characterization of early prostatic carcinomas in the ACI rat: a light and electron microscopic study

The ACI rat constitutes a unique model for human prostatic carcinogenesis. A high percentage of these animals spontaneously develop prostatic carcinomas in the ventral lobe as they age. The light microscopic appearance of these tumors is similar to the cribriform pattern of adenocarcinoma in human prostate. In order to further characterize this useful model, we carried out light and electron microscopy studies of the morphology of carcinomatous lesions developing in these animals. Sixteen rats ranging in age from 25 to 43 months were examined histologically, and ultrastructural studies were performed on eight of these cases. The neoplastic cells showed features of well-developed secretory epithelium including prominent Golgi apparatus, abundant rough endoplasmic reticulum, and numerous secretory vacuoles. Microvilli were numerous in some cells and focal apocrine secretory activity was present. Intraluminal crystals similar to those associated with human prostate carcinoma were observed in one of our cases. Prostate carcinomas developing in the ACI rat share many of the ultrastructural features of human prostatic carcinoma.     

正常大鼠心室肌弹性纤维和弹性蛋白的增龄变化

目的 探讨大鼠心脏发育过程中弹性蛋白的形态分布特点和增龄变化规律。 方法 取孕18d、生后10d、生后1个月和生后3个月大鼠各10只，采用地衣红染色、免疫组织化学和Western blotting技术，观测心室弹性纤维的分布和弹性蛋白表达的变化；利用图像分析系统对弹性蛋白进行定量分析，并对不同月龄心室弹性蛋白含量进行对比分析。结果 弹性纤维广泛分布于心外膜、心肌细胞周围、小动脉壁。弹性纤维形似发丝，无粗大纤维束；胎鼠至初生期增长迅速，幼年到成年期增速减慢。心内膜的弹性纤维在幼年期达到高峰，成年略有降低。结论 从胚胎至成年大鼠心室弹性纤维逐渐增加，这种变化是心肌生理性重构的重要组成部分。     

Pulmonary structural changes following microembolism and blood transfusion. A light and electron microscopic study

Blood stored under standard blood band conditions develops microaggregates of platelets and leukocytes. Dog lungs were studied by light and electron microscopy at intervals from 48 hours to six days following exchange transfusions of sublethal volumes of such microaggregate-rich blood through either standard or Dacron wool (Swank) transfusion filters. After transfusion through standard filters, the pulmonary microvasculature was extensively occluded by microemboli. Swelling of capillary endothelial cells, interstitial and alveolar edema, and hypoxic changes in types I and II alveolar epithelial cells were noted. Changes then progressively resolved. These detrimental changes were prevented when microaggregates were removed by Dacron wool (Swank) filters. Mechanical occlusion of the pulmonary vasculature probably plays a minor role in initiating the structural changes observed. Release of lysosomes from disintegrating microaggregates is believed to be the significant factor initiating a chain of events leading to progressive pulmonary damage.     

Proliferation of endothelial cells in estrogen-stimulated rat liver. A light and electron microscopic cytochemical study.

The mononuclear phagocytes (Kupffer cells) in the normal rat liver can be distinguished from the endothelial cells on the basis of their endogenous peroxidase activity in the endoplasmic reticulum and their exclusive ability to phagocytose large (0.81 mum.) latex particles. Using these cellular markers we have investigated the effects of an estrogen upon the mitotic activity and the ultrastructure of individual types of littoral cells in the rat liver. Adult female rats received a single 10-mg. injection of diethylstilbestrol, and at daily intervals up to 6 days their livers were fixed by perfusion and processed for localization of peroxidase. Mitotic figures were rare in untreated control animals, but dividing littoral cells with both positive and negative peroxidase reaction could be identified. The exclusive localization of injected latex particles in dividing peroxidase-positive cells indicated that peroxidase reaction identified the Kupffer cells not only in the interphase but also during the mitotic division. In estrogen-treated animals there was a sharp rise in the mitotic activity of littoral cells; the activity reached its peak on the 3rd day and returned to normal levels on the 6th day after the initial injection. A breakdown of the dividing cells on the basis of their peroxidase reactivity revealed that nearly the entire population of dividing cells consisted of peroxidase-negative endothelial cells. In addition, numerous hyperactive Kupffer cells containing large phagolysosomes with phagocytosed peripheral blood cells and latex particles were seen. Intermediate cell-types with cytochemical features between Kupffer cells and endothelial cells or between monocytes and Kupffer cells were not encountered. Because of the limited phagocytic capacity of hepatic endothelial cells, our observations would provide morphologic evidence in support of previous physiologic studies, indicating that estrogen treatment has little or no effect upon the particle clearing function of the reticuloendothelial system in rats. The rare but clear demonstration of dividing Kupffer cells in liver sinusoids would indicate that these cells are capable of self-replication in situ. Finally, our observations suggest that estrogens may play an important role in the pathophysiology of endothelial cells.     

The thyroid in the spontaneously hypertensive rat: A light and electron microscopic study

The present study was undertaken to seek ultrastructural changes in the thyroid gland of the spontaneously hypertensive rat which would contribute to the understanding of previously reported abnormalities in thyroid function. Light and electron microscopic observations and measurements of plasma T3 and systolic blood pressure were recorded from a colony of Wistar-Kyoto rats (WKY) and of spontaneously hypertensive rats (SHR). The systolic blood pressure of SHR was significantly higher than that of WKY but the plasma T3 levels of the two groups did not differ significantly. After administration of propylthiouracil (PTU), serum T3 levels and systolic pressure of both groups decreased. The size of the thyroid follicles in SHR was highly variable throughout the gland, and the colloid contained unevenly dense areas and cell debris. The follicular cells contained slightly dilated rough surfaced endoplasmic reticulum (ER) and numerous pleomorphic bodies of uneven density. After treatment with PTU, the vessels between the follicles of SHR did not become as dilated as those in WKY but the fine structure of follicular cells in SHR was similar to that of WKY and was characteristic of the typical thyroid response to PTU administration. We suggest that the thyroid in SHR does not respond adequately to the elevated TSH levels reported to be present in these animals, although it can respond to the highly elevated TSH levels which occur with PTU administration. This impairment most probably involves defects in synthesis and/or secretion of thyroid hormones in response to TSH stimulation.