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Results for “Morphological Characterization”

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At least 919 records · Page 51Linked to original sources

PubMed1998

Neuronal ceroid lipofuscinoses: a review.

Neuronal ceroid lipofuscinoses (NCLs) are among the most common neurodegenerative diseases in childhood but rarely present in adulthood. The main symptoms are psychomotor deterioration, visual failure, epilepsy and motor disturbances. The NCLs are morphologically characterized by the accumulation of lipopigments within numerous cell types and loss of neurons. Pathogenesis is unknown. The current clinical classification recognizes six classic types of NCL and several atypical forms. Electrophysiological and neuroradiological findings may be of diagnostic significance, but disease recognition rests on the demonstration of a typical ultrastructural pattern. Genetic studies have demonstrated that several different genetic loci are involved in the pathogenesis of NCL, but the molecular mechanisms underlying neuronal death and lipopigment accumulation are not understood.

Humans↗

PubMed1992

Enzyme activity analyses along ragged-red and normal single muscle fibres.

Mitochondrial myopathies are morphologically characterized by ragged-red fibres (RRF). Serial cross-section revealed that the ragged-red appearance was only focal. This is in agreement with a partial cytochrome c oxidase (COX) deficiency in chronic progressive external ophthalmoplegia (CPEO). Since most of these patients show deletions of the mitochondrial genome single fibre analyses were performed determining COX and succinate dehydrogenase (SDH) in serial muscle sections from two patients with CPEO. High SDH activity was demonstrated in RRF; in contrast COX activity was lower in RRF in a patient, possibly representing a focal assembly of mitochondria with deletions in their genomes. The variation of enzyme activities along the muscle fibre was especially high in RRF. This study presents the first quantitative evidence that enzyme activities vary considerably along fibres in muscle from patients with a mitochondrial myopathy.

Adult↗

PubMed1991

GAD and GABA in an enriched population of cultured GABAergic neurons from rat cerebral cortex.

To study various aspects of GABAergic metabolism in an easily accessible system, dissociated cells from postnatal rat cerebral cortex were cultured in a serum-based medium and characterized morphologically and biochemically. The majority (70-96%) of the neurons were GABAergic as determined by three double-labeling procedures. The specific activity of glutamine synthetase in the cultures was 4-5% of the levels in rat astrocyte cultures and intact rat brain, indicating that glia were a minor component. The developmental increase of GABA levels preceded the increase of GAD activity in both immunocytochemical and biochemical experiments. GABA turnover rates also increased with culture age and were 20-30% of GAD activity. Four anti-GAD antibodies, which recognize GAD subunits with differing molecular masses to varying degrees, were used to stain cultured neurons and make immunoblots. Immunoblots showed that the neurons contained two major subunits of GAD which differed in mass by 2 kDa. All four antibodies immunostained both neuronal perikarya and neurites but one antibody, which on the immunoblots predominantly labeled the GAD protein with the lower molecular weight, showed a somewhat more pronounced punctate staining, possibly indicating a principal localization to neurites.

Amino Acids↗

PubMed1992

The pathobiology of salivary gland. II. Morphological evaluation of acinic cell carcinomas in the parotid gland of male transgenic (MMTV/v-Ha-ras) mice as a model for human tumours.

In the transgenic TG.SH (mouse mammary tumour virus/v-Ha-ras) mouse, designed to develop mammary tumours, occasional spontaneous salivary gland tumours have been reported, predominantly in males. The incidence and histomorphology of salivary gland tumours in 73 TG.SH mice were surveyed and in total, 21.9% developed both overt and microscopic parotid tumours. The majority developed between 73 and 150 days of age. In 31.5% of the TG.SH mice, occasional unilateral, but more frequently bilateral exophthalmos due to hyperplasia of the intraorbital (Harderian) lacrimal gland was observed. In 70% of these animals, parotid tumours developed later. Since Harderian gland hyperplasia, occurring as early as 5 weeks of age, preceded the development of palpable salivary gland lesions, this stigma is useful for the early selection of animals likely to progress to tumour formation. Before tumour-bearing transgenic mice are considered to be suitable models of human neoplastic disease, morphological characterization is necessary to ensure that the tumours are histologically representative of the human lesions for which they are potential models. In this study, all parotid tumours consisted of acinar-like glandular structures with central lumina discernible by electron microscopy. Ultrastructurally, secretory granules evident in the apical cytoplasm of the tumour cells resembled the zymogen granules of the normal parotid acinar cell, and some cells had a prominent complement of rough endoplasmic reticulum. These features, along with focal amylase expression detected immunohistochemically in some parotid tumours, identified these neoplasms as acinic cell carcinomas that mimic the human salivary gland acinic cell carcinoma faithfully.

Animals↗

PubMed1996

Ebola virus infection in guinea pigs: presumable role of granulomatous inflammation in pathogenesis.

An approach combining virology with light and electron microscopy was used to study the organs of guinea pigs during nine serial passages of Ebola virus, strain Zaire. It was observed that the wild type of Ebola virus causes severe granulomatous inflammation in the liver and reproduces in the cells of the mononuclear phagocyte system (MPS). Based on morphological characterization, two types of virus-cell interactions were demonstrated. The obtained data evidenced for heterogeneity of the population of wild type of Ebola virus. The virus accumulated in the liver of the infected animals, and the lesions became more pronounced with passage. Degenerative changes appeared, and their severity was increased with passage in the other organs as well. The set of target cells diversified and, as a result, not only the MPS cells, but also hepatocytes, spongiocytes, endotheliocytes and fibroblasts became involved in the reproduction of Ebola virus. The possible role of granulomatous inflammation in the development of the adaptive mechanism of Ebola virus to guinea pigs is discussed.

Animals↗

PubMed1978

Diagnosis of intracranial space-occupying lesions with DTPA-Sn-99mTc.

DTPA-Sn-99 mTc is an excellent radionuclide for brain scintigraphy procedures with a rapid blood clearance through glomerular filatration. No previous preparation of the patient is necessary. We have studied forty nine patients with primary or metastatic brain tumours as well as calvarium metastases. There have been five false negatives. We have found three types of scintigraphic patterns depending on whether the lesion is better visualized in early or late images, or does not change throughout the study. The sequential brain study, obtaining views at five minutes, and at one and two hours post-injection allows for an adequate morphological characterization of the lesion and occasionally, a histological diagnosis.

Brain Neoplasms↗

PubMed1984

Preparation of a human lung purified plasma membrane fraction: confirmation by enzyme markers, electron microscopy, and histamine H1 receptor binding.

A simple and rapid method of isolating plasma membranes from human peripheral lung tissue is described. The method involves homogenization of tissue in 0.25 M sucrose-buffered medium followed by differential and sucrose density gradient centrifugation. Enzymatic and morphological characterization of the plasma membrane fraction revealed minimal contamination by nonplasma membrane fragments. The isolated plasma membranes showed an 18-fold purification of 5'-nucleotidase activity compared to the original homogenate. Electron-microscopic studies of the plasma membrane fraction revealed the presence of small membrane vesicles having a trilaminar membrane structure. To further examine the purity of the plasma membrane preparation, the binding of the H1 receptor antagonist, 3H pyrilamine, to the plasma membrane-enriched fraction was compared to the binding to crude membrane preparations. Both the plasma membrane-enriched fraction and the crude membrane preparation had similar Kd's for the histamine antagonist, but the plasma membrane-enriched fraction had a threefold greater binding capacity, reflecting the relative enrichment of plasma membranes of the preparation. Thus, a method has been developed for the isolation of plasma membranes from human peripheral lung which should provide material for a variety of biochemical and pharmacological studies.

5'-Nucleotidase↗

PubMed1982

Morphology of the intermediate stages in the lamellar to hexagonal lipid phase transition.

The addition of calcium to suspensions of egg phosphatidylcholine and cardiolipin converts multiwalled liposomes to the hexagonal (HII) phase (Rand, R.P., Sengupta, S. (1972) Biochim. Biophys. Acta 255:484-492). We have studied this lamellar to hexagonal phase transition by freeze-fracture, thin-section electron microscopy, and X-ray diffraction and have morphologically characterized the intermediate stages. The first step in the transition involves the invagination and fusion of bilayers, marked by the appearance of lipidic intramembrane particles and "crater-like" indentations, as the large liposomes are converted to smaller flattened and elongated vesicles. The next step is the formation of tightly packed hexagonal arrays of tubules, each tubule being about 11 to 15 nm in diameter. These tubules are filled with fluid and a lipid bilayer forms the wall of each cylinder. Finally this tubular bilayer phase is converted to the hexagonal (HII) phase, where the distance between tubes is 5.5 to 7.5 nm.

Cardiolipins↗

PubMed1985

The alkali burned cornea: electron microscopical, enzyme histochemical, and biochemical observations.

The early phase of wound healing after small central alkali burns of the guinea pig cornea was studied using electron microscopical, enzyme histochemical, and biochemical techniques. In the first phase, which was morphologically characterized by the destruction of the epithelium and keratocytes and by the infiltration of the cornea with polymorphonuclear leukocytes, an increase in the activity of lysosomal phosphatases and glycosidases (beta-D-glucuronidase, acid beta-D-galactosidase, beta-D-N-acetylglucosaminidase) was noticed. In the second phase, the cornea was invaded by capillaries and fibroblasts. In this phase, the activity of proteases (aminopeptidase M, dipeptidyl peptidase IV) increased intra- and extracellularly, suggesting that these enzymes may be involved in the turnover of the collagenous matrix and the ground substance. Using synthetic 4-methoxy-2-naphthylamine substrates and fluorescence-band detection techniques after isoelectric focusing, an increase in the activity of endopeptidases was demonstrated. The decreased activity of gamma-glutamyl transpeptidase may be linked with the activation of latent collagenase.

Alkalies↗

PubMed1994

MR imaging of benign fatty tumors in children: report of four cases and review of the literature.

This study correlates the magnetic resonance imaging characteristics with the pathologic findings in rare benign fatty soft tissue tumors in four children. A review of the literature is presented. Two cases of infiltrating lipoma displayed bright signal on both T1- and T2-weighted images, similar to that observed in subcutaneous fat. Histological study revealed extensive muscle infiltration by mature fat, with some areas of total fatty replacement. The case of facial lipomatosis revealed an extensive process of fatty invasion of adjacent soft tissue and osseous deformity by mass effect of the tumor. This lesion was bright on T1- and T2-weighted images. Histopathologic examination showed widespread invasion of squamous mucosa and skeletal muscle. The single case of lipoblastoma involved the presacral region and right buttock. This lesion, although bright on both T1 and T2 weighting, was relatively hypointense to subcutaneous fat on T1. Microscopic examination revealed a well-encapsulated fatty mass made up of cells ranging from lipoblasts to mature lipocytes. In childhood, when fatty lesions are almost always benign, a morphologic characterization by magnetic resonance may be sufficient basis on which to make critical therapeutic judgements.

Adolescent↗

PubMed1981

Primary culture of supporting cells from bovine testes.

Supporting cells from 6- to 8-wk-old bovine calf testes were maintained in cell culture and were characterized morphologically and biochemically. Light and electron microscopy showed that the cultures consisted principally of supporting cells that were identified as epithelial cells with nucleolar vesicles. The bovine supporting cells in culture responded to follicle stimulating hormone with increased cAMP synthesis and enhanced incorporation of [3H]leucine into secreted proteins. No androgen binding protein could be detected in the medium.

Androgens↗

PubMed1980

Cultivation of microvascular endothelial cells from human preputial skin.

A procedure is described for the isolation and cultivation of microvascular endothelium from human skin. Neonatal foreskins are pooled, washed, minced, and dissociated by a mixture of collagenase and dispase. Microvascular endothelium, liberated in the form of intact capillary fragments, is incompletely separated from fibroblasts and epidermal cells by sieving through nylon mesh, followed by velocity sedimentation on 5% bovine serum albumin. The endothelium-enriched fraction has been maintained in primary culture for up to 3 weeks. The resulting epithelioid colonies have been characterized morphologically by both light and transmission electron microscopy and manifest all of the structural features that distinguish other, large-vessel endothelia in culture. In addition, immunohistochemical studies using an indirect fluorescent antibody technique demonstrate that these cells contain the endothelium-specific product, Factor VIII antigen.

Blood↗

PubMed1986

Large scale preparation of rabbit aortic smooth muscle cells for use in calcium uptake studies.

Rabbit aortic smooth muscle cells were prepared by enzymatic digestion of the aortic smooth muscle layer. The cells were subcultured up to Passage 22 starting from a cryogenically preserved stock (approximately 10(10) cells, Passage 8) and characterized morphologically and for 45Ca++ uptake. Microscopically the cells demonstrated the characteristics of vascular smooth muscle cells. 45Ca++ uptake by the cells plated on tissue culture flasks (25 cm2) was determined at 25 degrees C in physiological salt solution (PSS) containing 45Ca++ in low (5 mM) or high (50 mM) KCl concentrations. At the end of the incubation period (0 to 30 min), PSS was aspirated and the cells quickly washed, digested with 0.5 N NaOH, and counted for 45Ca++. High K+ increased the 45Ca++ uptake by 100% or more compared to the low K+ uptake of 45Ca++. This K+-induced 45Ca++ uptake was eliminated in osmotically shocked cells, and inhibited by nifedipine, verapamil, and diltiazem, in a dose-dependent manner. The extent of 45Ca++ uptake and the inhibitory activity of nifedipine were retained up to Passage 22. It is concluded that the developed methodology for scaled-up cultures of rabbit aortic smooth muscle cells provides morphologically intact and biochemically functioning cells suitable for calcium channel studies.

Animals↗

PubMed1988

Three-dimensional organization of the extracellular matrix secreted by cultured rat smooth muscle cells.

Specific interactions between cells and the extracellular matrix (ECM) in which they are embedded play a vital role in tissue organization. In recent years, many of the individual components of the extracellular matrix have been isolated and their molecular structures elucidated, but the detailed topography of most extracellular matrices, as they are deposited by cells, is still largely unknown. In this study, the insoluble extracellular matrix produced by cultured rat vascular smooth muscle cells has been characterized morphologically using high-resolution electron microscopy of rotary platinum replicas. These cells grew as flat sheets in culture, secreting their matrix laterally and basally. The matrix was composed of a cross-linked fibrillar meshwork. Some fine fibers (10 to 15 nm in diameter) were naked, but most of the filamentous mesh was covered with coarse granular material. Limited digestion with trypsin or pancreatic elastase removed most of this coating, indicating that the granules were glycoproteins and proteoglycans. Another subset of matrix fibrils (20 to 40 nm in diameter) was identified as type I collagen by direct comparison with purified bovine skin collagen. In addition to exposing the underlying filamentous substructure of the matrix, protease treatment also revealed large, straight fiber bundles and globules of amorphous material suspended in the filamentous web. This novel view of a complex matrix promises to provide spatial information that will be useful in future studies of cell interactions with the ECM.

Ammonium Hydroxide↗

PubMed2001

Expression of type I, type II, and type X collagen genes during altered endochondral ossification in the femoral epiphysis of osteosclerotic (oc/oc) mice.

The osteosclerotic (oc/oc) mouse, a genetically distinct murine mutation that has a functional defect in its osteoclasts, also has rickets and shows an altered endochondral ossification in the epiphyseal growth plate. The disorder is morphologically characterized by an abnormal extension of hypertrophic cartilage at 10 days after birth, which is later (21 days after birth) incorporated into the metaphyseal woven bone without breakdown of the cartilage matrix following vascular invasion of chondrocyte lacunae. In situ hybridization revealed that the extending hypertrophic chondrocytes expressed type I and type II collagen mRNA, as well as that of type X collagen and that the osteoblasts in the metaphysis expressed type II and type X collagen mRNA, in addition to type I collagen mRNA. The topographic distribution of the signals suggests a possible co-expression of each collagen gene in the individual cells. Immunohistochemically, an overlapping deposition of type I, type II, and type X collagen was observed in both the extending cartilage and metaphyseal bony trabeculae. Such aberrant gene expression and synthesis of collagen indicate that pathologic ossification takes place in the epiphyseal/metaphyseal junction of oc/oc mouse femur in different way than in normal endochondral ossification. This abnormality is probably not due to a developmental disorder in the epiphyseal plate but to the failure in conversion of cartilage into bone, since the epiphyseal plate otherwise appeared normal, showing orderly stratified zones with a proper expression of cartilage-specific genes.

Animals↗

PubMed1983

Stereologic analysis of the ultrastructure in isolated human T and non-T lymphoid cells. II. Data on blasts in ALL; correlation with immunologic studies and FAB-morphology.

Leukemic cells from 20 cases of acute lymphoblastic leukemia (ALL), examined for T and B markers and classified according to FAB guidelines, were analyzed by electron microscopy. Using stereologic methods a quantitative morphologic characterization of the average blast, assumed to be of clonal origin and thus representative of the whole population, was obtained within each subset. Comparative studies of the ultrastructure of the T, B and non-T, non-B blast on one hand and of the FAB category L1 and L2 on the other were performed. No differences of cell volumes, total cell surface areas, nuclear volumes and surface areas or volumes of nuclear compartments were observed between the immunologically defined subsets. Minor variations were seen in the cellular surface contour, the B blast tending to be more irregular than the T blast. Features most predictive of the immunologic cell type were abundant rough ER in B-derived ALL, increasing with plasmacytoid differentiation, and an increase in dense granules which were often clustered in the vicinity of a well-developed Golgi complex in T ALL. The light microscopic criteria of the FAB classification were nearly all confirmed at the EM-level except that nuclear irregularity was observed to the same degree in both categories. Other differences not related to the FAB scheme were encountered in the volumes of the Golgi complex and of the mitochondrial compartment. Objective criteria as quantitative estimates of cellular structures may contribute to an improved subclassification in ALL.

Adolescent↗

PubMed1993

Improvements for the anatomical characterization of insect neurons in whole mount: the use of cyanine-derived fluorophores and laser scanning confocal microscopy.

The optical sectioning capability of the laser scanning confocal microscope was utilized to image dye-filled neurons within whole-mounted insect ganglia. Specific pterothoracic interneurons, in the moth Manduca sexta, were retrogradely filled with Neurobiotin and subsequently visualized with a monoclonal anti-biotin conjugated with one of the following fluorophores: fluorescein, and the newly developed cyanines, Cy3.18 (Cy3) and Cy5.18 (Cy5). Overall, the Cy5 fluorophore was best suited for imaging insect neurons within ganglia. This new methodology allowed us to identify and characterize morphologically a collection of descending multisegmental interneurons with large or small diameter somata. A variety of larger molecular weight (10,000 daltons) tracers was also used to examine the possibility of nonselective filling of neurons with Neurobiotin, possibly through gap junctions. We also investigated the usefulness of Cy3 and Cy5 as fluorophores for transmitter immunostaining of neurons in whole mount. Neurons immunoreactive for serotonin and the neuropeptides, FMRFamide and SCPB, were imaged in the brain and the pterothoracic ganglion. The central projections of some of these immunoreactive neurons were imaged in their entirety.

Animals↗

PubMed2004

[Engineering and characterization of functional osteochondral replacement tissue].

Extensive osteochondral lesions require repair of the cartilage and underlying bone. We generated osteochondral repair tissue by tissue engineering. Standardized defects, 7 x 5 x 5 mm, were created in femoropatellar grooves of adult rabbits. Engineered cartilage, generated in vitro starting from chondrocytes and a biodegradable scaffold, was implanted using Collagraft as subchondral support. Cell-free implants, defects left empty, and unoperated knee joints served as controls. Explants were characterized morphologically and mechanically. Engineered cartilage implants were superior to cell-free implants and to natural healing of empty defects with respect to the histologic score and Young's modulus of the 6-month repair tissue. These data suggest that engineered cartilage can provide primary stability for the treatment of critical osteochondral defects.

Bone Remodeling↗