Types Of Cytoplasmic Inclusions Research Articles

Ultrastructure of spermatozoa and female copulatory organs in preferably asexually-reproducing acoel Convolutriloba retrogemma (Acoelomorpha)

Acoela (Acoelomorpha) represents one of the most spectacular animal taxa with debatable phylogenetic position. Particularly, acoel genus Convolutriloba is of special interest due to the inhabitance mostly in marine aquaria and the development of unique ways of asexual reproduction, while the sexual one is rarely described. The aim of the present work is the ultrastructural investigation of reproductive system in preferably asexually-reproducing acoel Convolutriloba retrogemma, type species of the genus. In all specimens studied, the oocytes were absent, despite the spermatozoa and female copulatory organs (seminal bursa with mouthpiece) were being fully developed. The spermatozoon of C. retrogemma represents an elongated filiform cell with a pair of incorporated axonemes with a formula 9 + 0, axial microtubules and three types of cytoplasmic inclusions. The bursa mouthpiece is composed of matrix cells with the electron-dense sclerotized core surrounding the lumen, and electron-transparent periphery containing most cell organelles, as well as the intercalary (glandular) cells between them. In all individuals studied by electron microscopy, the lumen of the mouthpiece is always locked with a “plug” composed of various cellular elements, including the sclerotized actin fibers, preventing the insemination. The comparative morphology of the reproductive system of Convolutriloba and evolutionary role of asexual reproduction within this genus are discussed.

Replication of multiple system atrophy prions in primary astrocyte cultures from transgenic mice expressing human \u03b1-synuclein

Glial cytoplasmic inclusions (GCIs) containing aggregated and hyperphosphorylated α-synuclein are the signature neuropathological hallmark of multiple system atrophy (MSA). Native α-synuclein can adopt a prion conformation that self-propagates and spreads throughout the brain ultimately resulting in neurodegeneration. A growing body of evidence argues that, in addition to oligodendrocytes, astrocytes contain α-synuclein inclusions in MSA and other α-synucleinopathies at advanced stages of disease. To study the role of astrocytes in MSA, we added MSA brain homogenate to primary cultures of astrocytes from transgenic (Tg) mouse lines expressing human α-synuclein. Astrocytes from four Tg lines, expressing either wild-type or mutant (A53T or A30P) human α-synuclein, propagated and accumulated α-synuclein prions. Furthermore, we found that MSA-infected astrocytes formed two morphologically distinct α-synuclein inclusions: filamentous and granular. Both types of cytoplasmic inclusions shared several features characteristic of α-synuclein inclusions in synucleinopathies: hyperphosphorylation preceded by aggregation, ubiquitination, thioflavin S–positivity, and co-localization with p62. Our findings demonstrate that human α-synuclein forms distinct inclusion morphologies and propagates within cultured Tg astrocytes exposed to MSA prions, indicating that α-synuclein expression determines the tropism of inclusion formation in certain cells. Thus, our work may prove useful in elucidating the role of astrocytes in the pathogenic mechanisms that feature in neurodegeneration caused by MSA prions.

Defective autophagy is a key feature of cerebral cavernous malformations.

Cerebral cavernous malformation (CCM) is a major cerebrovascular disease affecting approximately 0.3–0.5% of the population and is characterized by enlarged and leaky capillaries that predispose to seizures, focal neurological deficits, and fatal intracerebral hemorrhages. Cerebral cavernous malformation is a genetic disease that may arise sporadically or be inherited as an autosomal dominant condition with incomplete penetrance and variable expressivity. Causative loss-of-function mutations have been identified in three genes, KRIT1 (CCM1), CCM2 (MGC4607), and PDCD10 (CCM3), which occur in both sporadic and familial forms. Autophagy is a bulk degradation process that maintains intracellular homeostasis and that plays essential quality control functions within the cell. Indeed, several studies have identified the association between dysregulated autophagy and different human diseases. Here, we show that the ablation of the KRIT1 gene strongly suppresses autophagy, leading to the aberrant accumulation of the autophagy adaptor p62/SQSTM1, defective quality control systems, and increased intracellular stress. KRIT1 loss-of-function activates the mTOR-ULK1 pathway, which is a master regulator of autophagy, and treatment with mTOR inhibitors rescues some of the mole-cular and cellular phenotypes associated with CCM. Insufficient autophagy is also evident in CCM2-silenced human endothelial cells and in both cells and tissues from an endothelial-specific CCM3-knockout mouse model, as well as in human CCM lesions. Furthermore, defective autophagy is highly correlated to endothelial-to-mesenchymal transition, a crucial event that contributes to CCM progression. Taken together, our data point to a key role for defective autophagy in CCM disease pathogenesis, thus providing a novel framework for the development of new pharmacological strategies to prevent or reverse adverse clinical outcomes of CCM lesions.

Renal epithelial neoplasms: The diagnostic implications of electron microscopic study in 55 cases

Several unsettled histogenetic, nosologic and diagnostic considerations for renal epithelial tumors may have ultrastructural ramifications. Yet, a comprehensive electron microscopic study of renal epithelial neoplasms, in light of the recent classification, is not available. The ultrastructural findings from fifty-five renal epithelial neoplasms [31 clear cell renal cell carcinomas (RCC), 11 papillary RCC, 5 chromophobe RCC, 3 sarcomatoid RCC and 5 oncocytomas] were correlated with their light microscopic appearance. Clear cell RCC showed long microvilli similar to the brush border of the normal proximal tubules, with abundant cytoplasmic lipid and glycogen. Papillary RCC showed variably sized microvilli, and small amounts of cytoplasmic lipid, but no glycogen. Chromophobe RCC showed many cytoplasmic vesicles and abnormal mitochondria, with rare short and stubby microvilli. Renal oncocytoma showed many mitochondria with a few vesicles in the apical portion of the cytoplasm and rare short and stubby microvilli. The eosinophilic cell variants of clear cell RCC, papillary RCC and chromophobe RCC showed ultrastructural features similar to those of their respective prototypes, except for an increased numbers of mitochondria in the cytoplasm. One sarcomatoid clear cell RCC showed skeletal muscle differentiation. Two types of cytoplasmic inclusions, i.e. hyaline globules and granules similar to those in the Paneth cells (PC-like granules) were identified only in clear cell RCC, which displayed distinctive ultrastructural features. The current EM study demonstrates distinctive ultrastructural features of renal epithelial neoplasms. The findings lend additional support to the current classification of the pertinent tumor types, facilitate the differential diagnoses, and provide insights into the possible histogenesis of renal epithelial neoplasms. HUM PATHOL 33:68-79. Copyright © 2002 by W.B. Saunders Company

Secretory Function of the Test Cell in Larval Tunic Formation in the Ascidian Ciona intestinalis: An Immunoelectron Microscopic Study

Abstract The test cells, one of the two accessory cell groups of the ascidian oocyte, persist around the developing embryos and the hatched tadpole larvae, but their function during embryogenesis is not fully understood. We have produced monoclonal antibodies that specifically recognize the test cells in Ciona intestinalis (Takamura et al., Zool. Sci. 13: 241-251, 1996). In the present paper, we demonstrate the ultrastructural localization of the antigen reactive to one of the test cell-specific antibody UA165 by immunogold labeling. The mature test cells in Ciona intestinalis contain two types of cytoplasmic inclusions, i.e., irregular vacuoles with electron-dense cores and spherical vesicles with a moderately electron-dense content. UA165-immunogold particles specifically labels the content of the spherical vesicles. Concomitantly with larval tunic formation at the early tailbud stage, the spherical vesicles begin to rupture and the UA165 antigen is exocytosed into the perivitelline space surrounding th...

The clinical significance of cytoplasmic inclusions(CPI) in synovial fluid examination.

The clinical significance of cytoplasmic inclusions(CPI) in synovial fluid(SF) examination was evaluated. We examined SF specimens collected from major rheumatology clinics in the Philadelphia area during the period of January to December 1995. Among 759 patients in the initial study group, 419 cases with established diagnoses and full synovial analyses were included. Their diagnoses and SF analysis results including leukocyte counts, differential counts and wet preparations were collected and analysed. Ninety seven of the 419 SF specimens were found to have CPI. CPI were found in SF from almost all rheumatic diseases. They were most likely to be found in inflammatory arthropathy including rheumatoid arthritis(RA, 46%), juvenile rheumatoid arthritis(JRA, 78%) and psoriatic arthritis(55%). On the contrary, CPI were least common in crystal-induced arthropathy among the inflammatory arthropathy. CPI were found 8 out of 98 gout cases(8%) and 2 among 53 calcium pyrophosphate dihydrate(CPPD) deposition disease(4%). In noninflammatory arthropathy, CPI were found in only 6 cases(6%) out of the 103 osteoarthritis(OA). In RA cases with non-inflammatory SF, 4 of the 20 SF(20%) had CPI while only 6% of OA SF had CPI. OA SF with CPI were all noninflammatory SF. In summary, CPI were a common finding on SF examination. CPI were more likely to be found in inflammatory arthropathy than noninflammatory. Among inflammatory arthropathy, CPI can favor non-crystal arthropathy than crystal arthropathy. Awareness of the presence of CPI is suggested as an addendum to routine SF analysis. Renewed investigation of the several types of CPI may add further to the understanding of joint disease.

Cytopathology and ultrastructure of mild and severe strains of maize chlorotic dwarf virus in maize and johnsongrass

In maize leaves experimentally infected with various isolates or strains of maize chlorotic dwarf virus, including a newly characterized strain (M1), and in naturally infected johnsongrass, only two types of cytoplasmic inclusions were consistently observed: (i) quasi-spherical electron-dense granular inclusions, and (ii) curved or straight bundles of fibrous inclusions. Both types were detected by light and (or) electron microscopy in vascular parenchyma and phloem cells, and less frequently in bundle-sheath and adjacent mesophyll cells. The dense granular inclusions usually contained numerous isometric virus-like particles, some of which may have been released into the surrounding cytoplasm. However, a high proportion of these inclusions in cells infected with the mild type strain and a type-like isolate (M8) were either devoid of or contained very few viruslike particles. In maize leaves infected with the white stripe (WS) isolate, the chloroplasts were markedly deformed; in leaves of stunted plants doubly infected with M8 and the serologically distinct M1 strain, some phloem cells appeared degenerated. Electron microscopy of preparations of purified M1 stained with uranyl acetate revealed both stain-impenetrable full particles and stain-penetrable empty or partially empty particles. Both full and apparently empty particles were also found in cells of maize leaves infected with M1, whereas with other strains and isolates, mainly full particles were found both in situ and in vitro. Key words: maize chlorotic dwarf virus, cytopathology, ultrastructure, maize, johnsongrass.

Pathobiochemical aspects of cytoskeleton components.

This review summarizes pathobiochemical aspects of diseases, in which cytoskeletal components play a crucial role in pathogenesis. An attempt to classify the disorders on the basis of phenotypic changes that occur in microfilaments, intermediate filaments and microtubuli was unsuccessful. Three groups of disorders are presented: 1. cytoplasmic inclusions in specific diseases (merely descriptive); 2. diseases with genetic defects in cytoskeletal proteins (a chain of causality from defect to phenotype, in some cases with large gaps); 3. diseases with suspected involvement of cytoskeleton (hypothetical causal chain). Microfilaments are involved in certain pathogenetic processes on account of defects in their associated proteins; in Duchenne muscular dystrophy, dystrophin is defective, while the defective protein in Rett syndrome is synapsin. Defects in spectrin and membrane anchor proteins lead to disorders of the red cell membrane skeleton (congenital haemolytic anaemias). Intermediate filaments accumulate in some types of cytoplasmic inclusions, together with ubiquitin (Mallory bodies, desmin accumulation in some myopathies and others). A pathogenetic interpretation of this phenomenon is lacking. A genetic defect in certain types of keratin is the cause of epidermolysis bullosa. Interesting preliminary results are reviewed that reveal the crucial role of cytoskeletal components in a further group of diseases (intrahepatic cholestasis, Alzheimer disease, pemphigus). These disorders are currently under investigation, or are of theoretical interest with respect to the cytoskeleton. Specific reactions of cytoskeletal components in serum, which might be used diagnostically, have not been found.

Molluscum contagiosum associated with AIDS: a case report with ultrastructural study

The clinical features of perioral molluscum contagiosum in a patient with the acquired immunodeficiency syndrome are described. Light microscopy and thin section electron microscopy revealed epidermal cells in different stages of degeneration showing two types of cytoplasmic inclusions. The basement membrane exhibited discontinuities and multiple laminations which may be a response to viral-induced cytotoxic effects.

A new type of cytoplasmic inclusion in human choroid plexus. A histochemical, ultrastructural and frequency study.

We described a new type of cytoplasmic inclusion in the choroidal epithelial cells of humans. The inclusions usually appeared as brown, round or elongated bodies with or without an inner core, ranging in size from 1.3 to 7.0 micron. Histochemically, they contained polysaccharides, proteins and compound lipids. Ultrastructurally, they were composed of finely granular and filamentous materials, which are densely packed in the inner core and less dense in the outer zone. The frequency study of the inclusions in 197 autopsied patients revealed that their occurrence had no correlation with the age or the disease category. It is concluded that the inclusions are a nonspecific, but peculiar, change of the choroidal epithelial cells, probably representing the morphological expression of a physiological or pathological alteration of the cellular metabolism at the single-cell level.

Clinico-pathological variability in the childhood neuronal ceroid-lipofuscinoses and new observations on glycoprotein abnormalities.

Our 86 cases of neuronal ceroid-lipofuscinosis (NCL) included 7 children with the infantile variant, 28 with the late infantile variant, and 51 with the juvenile variant. Thirty-one cases were drawn from a NCL registry and were not evaluated personally by the authors. Another 30 cases from the registry were not included because of inadequate data. The clinical course was subacute in most children with the infantile and late infantile variants and chronic in the juvenile variant. Sixteen of 86 cases (19%) were considered to be atypical clinically [3/7 (43%) with the infantile variant, 3/28 (11%) with the late infantile variant, and 10/51 (20%) with the juvenile variant]. Clinical variability among and between families was most striking in the juvenile variant. Pathological investigations of skin, buffy coat and/or brain showed atypical and/or more than one type of cytoplasmic inclusions in 10/50 (20%) of late infantile and juvenile variants. All of the children with the infantile variant had granular, osmiophilic profile in tissues. Biochemical studies on the glycoproteins of cultured fibroblasts in three cases of juvenile NCL showed that there was a higher proportion of one size class of N-linked oligosaccharides and a higher proportion of mannose-containing glycoproteins in NCL than in control cells. This supports previous lectin histochemical studies of glycoconjugates in skin of juvenile NCL [Wisniewski and Szumanska, 1986] and suggests that there may be defects in the processing of N-linked oligosaccharides in the glycoproteins of juvenile NCL.

Cytoplasmic inclusions in Giardia: an electron microscopy study.

Ultrastructural observations of Giardia trophozoites showed two different types of cytoplasmic inclusions. In Giardia muris from hamsters, the inclusions scattered in the cytoplasm were round, about 0.2 micron in diameter, limited by a double membrane, and with some electron-dense contents. In G. duodenalis from domestic rats, the inclusions were polyhedral, about 0.2 micron in diameter, limited by a double membrane, and with less electron dense contents. These inclusions have an unknown nature, and evidences show interaction between the inclusions and the Giardia trophozoites.

Isolation and partial characterization of the amorphous cytoplasmic inclusions associated with infections caused by two potyviruses

The potyviruses pepper mottle (PeMV) and watermelon mosaic virus-1, a strain of papaya ringspot (PRSV-W), induce the formation of a second type of cytoplasmic inclusion in addition to cylindrical (pinwheel) inclusions. The conspicuous aggregates of electron-dense material with imperfect spherical shapes have been called amorphous inclusions (AI). The AI were isolated from extracts of infected tissue using a combination of clarification with Triton X-100 and low-speed centrifugations through sucrose cushions. Electrophoresis, in sodium dodecyl sulfate-permeated polyacrylamide gels (SDS-PAGE), of the SDS-dissociated AI revealed a single constituent protein with a molecular weight of 51,000. SDS-PAGE-purified AI proteins were immunogenic and serologically unrelated to proteins of host, capsid, cylindrical inclusions, and tobacco etch virus nuclear inclusions. The AI protein of PeMV was distinct from the AI protein of PRSV-W on the basis of peptide analysis and serological tests. The antisera prepared to SDS-PAGE-purified AI proteins reacted specifically with Al in situ in immunofluorescence tests. The characteristics of the AI indicate that they are of viral origin.

Elemental analysis of particles in fungal zoospores

The elemental composition of gamma particles in zoospores ofAllomyces macrogynus andBlastocladiella emersonii was determined by use of energy dispersive X-ray analysis of glutaraldehyde fixed, thin section zoospores. Isolated preparations of gamma particles were also examined. Gamma particles contained no detectable elements. Similar sized, globular, electron dense cytoplasmic inclusions contained phosphorus and calcium. We suggest that previous studies assigning calcium and phosphorus to gamma particles may have been based on confusion of these two types of cytoplasmic inclusions.

Myelin-like inclusions in maturing and senescent muscle cells of rat myocardium

This paper deals with the ultrastructure of two types of cytoplasmic inclusions, “mylein figures” and “lipid complexes”, present in muscle cells of ventricular myocardium of the rat heart. The inclusions were numerous in both the first two postnatal weeks and in the senescent stages, being rarely observed in young adult animals. The myelin figures were entirely made up of myelin-like membrane whorls, whereas the lipid complexes exhibited discrete myeloid caps surrounding a central lipid core. The origin and functional significance of such myelin-like structures are discussed on the basis of ultrastructural and biochemical studies on myocardial physiology and age-related evolution.

Unusual Cytoplasmic Inclusion Bodies in Medullary Carcinoma of the Thyroid

Medullary Thyroid Carcinoma(MTC) was first described by Hazard et al. and it is known to be C-cell origin and one of the members of APUDomas. Recently we have studied ultrastructural characteristics of 17 cases of MTC and this report describesultrastructural features of an unusual case in which 4 types of cytoplasmic inclusions other than typical secretory granules and ordinary cytoplasmic organelle were observed. The clinical and histologic features of this case were typical of the MTC and the patient was treated with Co radiation 90 days prior to the surgery. Small pieces of the tumor tissues(lymph node metastasis) obtained from 43 year-old male patient at total thyroidectomy and left modified neck disection were prepared for transmission electron microscopy by standard methods.

Brain aging in normotensive and hypertensive strains of rats. II. Ultrastructural changes in neurons and glia.

A variety of age-related changes occur in the structure of neurons in the cerebral cortex of Wistar-Kyoto and spontaneously hypertensive rats. The most marked alteration associated with increasing age was the deposition of lipofuscin pigment, primarily at the bases of apical dendrites of pyramidal neurons. While no strain-related differences in the amount of lipofuscin pigment were observed in the youngest (3 months) and in the aged (22-27 months) groups of rats, it appeared that hypertensive rats had larger pigment deposits at 12 months of age. At the ultrastructural level, neurons of the aged brains exhibited numerous nuclear invaginations and filamentous nuclear inclusions, increased amounts of Golgi complex and two types of cytoplasmic inclusions. The number of degenerative structures in the neuropil (membranous whorls, dystrophic axons and alterations in myelin sheaths) was also apparently increased in the aged brains. Neurofibrillary tangles were observed in dendritic processes of a 27-month-old Wistar-Kyoto rat. Glial cells accumulated distinctive pigment granules by which the three types of glia could be identified.

Ultrastructure of the Bunina bodies in anterior horn cells of amyotrophic lateral sclerosis.

Light and electron microscopic studies were made on the anterior horn cells in a case o amyotrophic lateral sclerosis. Eosinophilic inclusions of Bunina type were observed almost selectively in the motor neurons of spinal cord, as well as of brain stem, at the light microscopic level. Fine structural study revealed the presence of two types of cytoplasmic inclusions. The first, mainly corresponding to the light microscopic inclusions, were homogeneous, electron-dense, round- or oval-shaped bodies with vesicular or tubular rims and ribosome particles, about 2-5 mu in diameter, which contained filaments or other cytoplasmic componenets in the clear areas within them. The second were lamellar structures (laminated cytoplasmic bodies, Morales) which appeared to be originating from endoplasmic reticulum. There was no distinct transition in these two types of inclusions and the relationship to each other is not clear. The significance of Bunina body is unknown, but some manifestation of a primary disorder, e.g., protein metabolism, rather than a secondary degenerative change in the motor neurons in amyotorophic lateral sclerosis.

Ultrastructural aspects of experimental swinepox with special reference to inclusion bodies

A light and electron microscopic study was performed on pox-like epidermal lesions in an experimentally infected pig. Light microscopical investigation of semithin sections revealed the presence of nuclear vacuoles and of different types of cytoplasmic inclusions. In electron microscopical studies large numbers of both immature and mature virus particles and the cytological changes indicative of pox virus infection were observed. Various types of intra-cytoplasmic inclusions -- i.e. fibrillar inclusions, crystalloid-containing dense inclusions, complex membraneous inclusions and dense homogeneous inclusions -- were encountered in addition to viroplasms and nuclear vacuoles. Because of the presence of vacuoles in nuclei of stratum spinosum cells the diagnosis swine pox by swinepox virus was most probable. These nuclear vacuoles have not been described in swine pox caused by vaccinia virus, the only other known cause of pox in swine.

Unusual, rod-shaped cytoplasmic inclusions (Hirano bodies) in a cerebellar hemangioblastoma

The present study reports unusual, long, tubular, rod-shaped cytoplasmic inclusions found in the stromal cells of a cerebellar hemangioblastoma, associated with von Hippel-Lindau syndrome. These inclusions have two layers of circular, laminated filaments, and longitudinally arranged filaments; and appear similar to the so-called "Hirano bodies", which have been previously found in normal and various pathologic conditions of the brain tissue, skeletal muscle cells in myopathy, and interstitial cells of the testis. A review of previous ultrastructural studies of cerebellar hemangioblastoma shows several different types of cytoplasmic inclusions, but none are found to be identical to the present report.