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PubMedDate not supplied

Morphological characterization of tube-like structures in hypersensitive human radicular dentine.

OBJECTIVES: The objective of this work was to determine if there were differences in the distribution of tube-like structures within the tubules of biopsies from hypersensitive versus non-sensitive human cervical radicular dentine. METHOD: Ten pairs of dentine were made from the exposed sensitive and non-sensitive radicular dentine of nine adult patients complaining of dentine sensitivity. The biopsies were made with a small hollow diamond bur. The specimens were submitted to HCl-collagenase treatment to partially digest the surface to permit visualization of subsurface structures. Half of the specimens were embedded in resin to facilitate longitudinal sectioning, and the other half were processed with embedding for SEM and EDS observation. RESULTS: Biopsies from hypersensitive regions exhibited hollow, tube-like structures within the lumina of dentinal tubules in 75.8 +/- 9.4%) ( mean +/- S.D.) of the tubules. In biopsies of non-sensitive areas of the same teeth, these tube-like structures were only seen in 20.4 +/- 8.5% of the tubules. In specimens that were embedded prior to treatment with HCl-collagenase, resin tags penetrated many of the tubules from hypersensitive dentine but few of the tubules from non-sensitive dentine. CONCLUSION: It is speculated that tube-like structures found in hypersensitive dentine play a role in maintaining the patency of the tubules which may prevent physicochemical processes from spontaneously occluding the tubules, thereby maintaining dentine sensitivity.

Adult↗
PubMed1992

Chemical identification and morphological characterization of the inferior olive in the frog.

Tritiated D-aspartate was injected into the cerebellar cortex of grassfrogs, Rana temporaria. Retrograde labeling was observed in a cell column of the contralateral caudal medulla, but not in other areas known to give rise to cerebellar mossy fibers. The aspartate-positive neurons are therefore considered to represent the origin of cerebellar climbing fibers in the inferior olive, as reported earlier for rat and turtle by other investigators. Contrary to earlier reports we found no extraolivary climbing fibers in the VIIIth nerve and in Scarpa's ganglion. Our results support the view that the climbing fiber system of vertebrates is anatomically, physiologically and chemically very distinct and phylogenetically very conservative.

Animals↗
PubMed1982

Biochemical and morphological characterization of sympathetic neurons grown in a chemically-defined medium.

Previous studies have demonstrated that individual neurons from neonatal rat superior cervical ganglion express a mixed adrenergic-cholinergic phenotype when grown under certain tissue culture conditions. The expression of this phenotype is critically influenced by a number of undefined components present in the culture medium. In the present study, we have examined whether superior cervical ganglion neurons grown on a chemically defined serum-free medium similarly develop dual transmitter expression, or if under these conditions, neurons express only those properties characteristic of their adrenergic heritage. To address this issue, we established that superior cervical ganglion neurons could be maintained in culture for extended periods on the defined medium described by Bottenstein & Sato in the absence of supporting cells. We then studied the biochemical, immunocytochemical and ultrastructural characteristics of these neurons. We found that in defined medium, superior cervical ganglion neurons continued to express, in a modified form, certain of their expected adrenergic properties, including the development of tyrosine hydroxylase and dopamine-beta-hydroxylase activities, stores of endogenous norepinephrine, synaptic vesicles with dense cores and tyrosine hydroxylase-immunoreactive staining properties. Superior cervical ganglion neurons grown on a defined medium did not, however, acquire cholinergic traits in culture. In this paper we show that choline acetyltransferase activity did not reach detectable levels; the comparison paper documents that cholinergic synapses were not formed. We concluded that superior cervical ganglion neurons, grown under serum-free culture conditions, develop certain properties characteristic of adrenergic neurons and do not express a mixed adrenergic-cholinergic phenotype. A comparison paper describes the electrophysiological properties of these neurons and demonstrates the frequent occurrence of electrotonic synapses in these cultures.

Adrenergic Fibers↗
PubMed1987

Morphological characterization of the rat striatal neurons expressing calcineurin immunoreactivity.

Calcineurin, a multifunctional Ca2+ (divalent cations)-dependent calmodulin-stimulated phosphoprotein phosphatase, has been reported to be present in the striatal neurons which project to the globus pallidus and the substantia nigra. In the present study, we examined what types of cells in the rat striatum express calcineurin. The calcineurin-positive neurons were of medium size (mean diameter of 16 microns) and constituted about 60-70% of the total neuronal population in the striatum. Under light microscopy, the calcineurin-positive neurons had round, triangular, or polygonal cell bodies with a relatively small amount of cytoplasm. Electron microscopic examination of 20 randomly selected striatal calcineurin-immunoreactive neurons revealed that their nuclei did not show any invaginations or intranuclear inclusions. The calcineurin-positive neurons were characterized by Golgi impregnation as the densely spinous type. On the other hand, it was demonstrated that calcineurin-positive neurons are a separate population from the diisopropylfluorophosphate-acetylcholinesterase-positive cells or nicotinamide adenine dinucleotide phosphate diaphorase-positive cells, by means of the combination of immunocytochemistry and enzyme histochemistry. In addition, simultaneous localization of calcineurin and substance P in a single cell was observed in some striatal neurons using a double immunostaining method. On the basis of these findings, it was considered that most calcineurin-immunoreactive neurons in the rat striatum may be classified as medium-size densely spiny neurons.

Acetylcholinesterase↗
PubMed1985

Physiological and morphological characterization of efferent neurones in the guinea pig cochlea.

Efferent neurones within the intraganglionic spiral bundle of the guinea pig cochlea were characterized in terms of their response properties, and their pattern of termination within the receptor organ revealed by intracellular labelling with horseradish peroxidase. All neurones subsequently identified as efferent neurones had clear features of their response properties which distinguished them from primary auditory afferents. They had long latency, low maximum discharge rate and low levels of spontaneous activity under Nembutal/Innovar anaesthesia. The pattern of discharge was extremely regular, revealed by symmetrical interspike interval histograms. 49.4% responded best to ipsilateral, 43.3% to contralateral sound and a third group of 7.3% responded equally well to either ipsilateral or contralateral sound. In cochleae in good physiological condition, these efferents were as sensitive and as sharply tuned as primary afferents with the same characteristic frequencies (CFs). All efferents fully traced in histological processing terminated on the outer hair cells. Several efferents showed extensive branching beneath the inner hair cells which might represent en passant synapses with other neuronal elements. There was clear evidence of tonotopic organization of the efferent projection. The site of termination on the outer hair cells in most instances was very close to the region of the cochlea predicted from the fibres' CF and the known place-frequency map for primary afferent neurones in the guinea pig.

Anesthesia, General↗
PubMed2006

Nature identification and morphology characterization of cation-exchange membrane fouling during conventional electrodialysis.

The aim of this work was to study the effect of a concentrate solution pH value and of the composition in calcium, carbonate, and protein of a diluate solution to be treated by conventional electrodialysis on the fouling of cation-exchange membranes (CEM). It appeared that after demineralization of solutions containing CaCl(2) and CaCl(2)+Na(2)CO(3) using a concentrate solution maintained at a pH of 12, mineral fouling appeared on both sides of the CEM. The nature of the deposits was identified as calcium hydroxide and/or carbonate on both surfaces. The mineral fouling presented an aggregation-like crystal following a carnation-like pattern of aggregates of small rhombohedral crystals with CaCl(2) added alone, while CaCl(2)+Na(2)CO(3) yielded a smoother spherical crystal. Protein fouling was detected only on the CEM surface in contact with the diluate after demineralization of a solution containing CaCl(2)+Na(2)CO(3) using a concentrate pH value of 2.

Calcium↗
PubMedDate not supplied

Morphological characterization of ductular reactions in canine liver disease.

Intrahepatic bile duct proliferation (ductular reaction) was examined histologically, immunohistochemically and ultrastructurally in four cases of canine liver disease, diagnosed as chronic hepatitis, liver fibrosis, cirrhosis and cholangiocellular carcinoma. Ductular reaction was a common finding in all cases. Most of the proliferated bile ducts were similar to normal bile ducts. In addition, duct-like structures occurred, consisting of hepatocytes and of intermediate cells that had phenotypic characteristics of both cholangiocytes and hepatocytes. The proliferated bile ducts were immunohistochemically negative for proliferating cell nuclear antigen (PCNA) and stem cell factor (SCF). The proliferated bile ducts in these four cases of canine liver disease thus showed both typical ductular reactions, such as elongation and tortuosity of the existing bile ducts, and atypical ductular reactions resulting from metaplasia of hepatocytes.

Animals↗
PubMed2004

Electrophysiological and morphological characterization of a case of autosomal recessive congenital myasthenic syndrome with acetylcholine receptor deficiency due to a N88K rapsyn homozygous mutation.

Congenital myasthenic syndromes are rare heterogeneous hereditary disorders, which lead to defective neuromuscular transmission resulting in fatigable muscle weakness. Post-synaptic congenital myasthenic syndromes are caused by acetylcholine receptor kinetic abnormalities or by acetylcholine receptor deficiency. Most of the congenital myasthenic syndromes with acetylcholine receptor deficiency are due to mutations in acetylcholine receptor subunit genes. Some have recently been attributed to mutations in the rapsyn gene. Here, we report the case of a 28-year-old French congenital myasthenic syndrome patient who had mild diplopia and fatigability from the age of 5 years. His muscle biopsy revealed a marked reduction in rapsyn and acetylcholine receptor at neuromuscular junctions together with a simplification of the subneural apparatus structure. In this patient, we excluded mutations in the acetylcholine receptor subunit genes and identified the homozygous N88K rapsyn mutation, which has already been shown by cell expression to impair rapsyn and acetylcholine receptor aggregation at the neuromuscular junction. The detection of the N88K mutation at the heterozygous state in five of 300 unrelated control subjects shows that this mutation is not infrequent in the healthy population. Electrophysiological measurements on biopsied intercostal muscle from this patient showed that his rapsyn mutation-induced fatigable weakness is expressed not only in a diminution in acetylcholine receptor membrane density but also in a decline of endplate potentials evoked at low frequency.

Adult↗
PubMed2004

Morphological characterization of Anticarsia gemmatalis M nucleopolyhedrovirus infection in haemocytes from its natural larval host, the velvet bean caterpillar Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae).

For a better understanding of virus x host interactions, transmission electron microscopy was used to characterize the intrahaemocoelic infection of Anticarsia gemmatalis larval haemocytes by A. gemmatalis M nucleopolyhedrovirus (AgMNPV). At 12 h post-infection (h p.i.), we observed nuclear hypertrophy, budded virus assembling, and protrusion towards the cytoplasm, virion envelopment, and accumulation of fibrillar aggregates in the cytoplasm. Around 24 h p.i., fibrillar aggregates also appeared inside nuclei of infected cells. By 48 h p.i., virogenic stroma and polyhedra were visualised in nuclei and at 72 h p.i., widespread infection in haemocytes was observed. Cell remnants and free polyhedra were phagocytosed by granular haemocyte 1 and plasmatocytes. Entire cells were phagocytosed only by plasmatocytes. Necrosis of infected cells was quite common, suggesting a putative cytotoxic response. Granular haemocyte 1 presented a more exuberant protrusion of budded viruses in comparison to other haemocytes. All types of haemocytes were shown to be infected, and the intense virus replication in some of these cells reveals the importance of haemolymph for AgMNPV spread in its natural host, a critical factor for permissiveness.

Animals↗
PubMed1983

Alterations in somatostatin and other islet cell functions in the spontaneously diabetic BB Wistar rat: biochemical and morphological characterization.

In the present study we have attempted to assess the functional status of somatostatin cells in relation to the function of the other islet cell types (B, A, and PP cells) in the BB Wistar rat. Somatostatin-like immunoreactivity (SLI), glucagon, and insulin were measured in extracted plasma obtained from the hepatic portal vein (PV) and inferior vena cava (IVC) of acutely diabetic untreated rats, insulin-treated diabetic rats and nondiabetic controls. Extracts of the pancreas were assayed for SLI, glucagon, and insulin, and the pancreatic populations of A, B, D, and PP cells were evaluated by morphometry. Extrapancreatic somatostatin changes were assessed by measurement of SLI in extracts of the whole gut, hypothalamus, and retina. Direct studies of SLI, glucagon, and insulin secretion in response to glucose, arginine, and theophylline were carried out using the isolated perfused pancreases of two separate groups of untreated diabetic and nondiabetic rats. Our results showed that in the severely insulin deficient BB Wistar rat (1) pancreatic concentrations of SLI, glucagon, and insulin were reduced; (2) the B cells are virtually eliminated and the D cells severely reduced early in diabetes; A and PP cells are resistant initially but eventually sustain major losses as observed in terminal islets; (3) retinal SLI is reduced, but SLI in gut and brain appears unchanged; (4) the secretion of SLI, glucagon, and insulin from the perfused pancreas is diminished 60%, 36%, and 99%, respectively; (5) PV and IVC blood levels of SLI and glucagon are elevated despite decreased pancreatic secretion; (6) The trans-hepatic gradient of SLI is reduced; and (7) Insulin treatment normalizes the elevated PV and IVC levels of SLI and glucagon. It is concluded that the elevated PV and IVC levels of SLI are secondary to insulin deficiency and result from increased SLI secretion most probably from the gut and from diminished hepatic metabolism. The origin of the hyperglucagonemia is less certain, but as in the case of SLI, important contributions from extra-pancreatic secretion appears likely.

Animals↗
PubMed1998

Primary nonurachal adenocarcinoma in the bilharzial urinary bladder: deoxyribonucleic acid flow cytometric and morphologic characterization in 93 cases.

OBJECTIVES: To characterize adenocarcinomas of the urinary bladder by their DNA profiles and their proliferative properties. METHODS: Primary nonurachal adenocarcinomas, found in 93 patients with bilharzial bladder carcinomas, were studied using DNA flow cytometry. Tumor ploidy and S-phase fraction were related to tumor grade, stage, cell type, and lymph node status. RESULTS: Aneuploidy with high S-phase fractions, found in 90% of the tumors, demonstrates the high malignancy potential of these tumors, the majority of which were found to be muscle-infiltrative. There were no relationships between ploidy or S-phase fraction and tumor grade and stage. Lymph node metastases, present in 24% of the 93 patients, were found exclusively in nontetraploid aneuploid tumors with high S-phase fractions exceeding 100%. Paraffin-embedded tissues compared with fresh material gave the same information on ploidy, whereas bladder washing did not provide adequate information. CONCLUSIONS: The high aggressiveness of adenocarcinomas in the biharzial bladder is confirmed and can be explained by their proneness to develop gross chromosomal aberrations combined with high cell proliferation.

Adenocarcinoma↗
PubMed2002

Zebu (Bos indicus) ovarian preantral follicles: morphological characterization and development of an efficient isolation method.

Preantral follicles are a major source of oocytes, and their utilization as an important tool to store large number of female gametes for future use in reproductive programs has been investigated. The increasing importance of studies in this subject, together with the important role of Zebu cattle in the economy of tropical and subtropical countries as well as their well-known differences from European cattle, led to this research. The present study aims to determine the best size interval for sectioning ovarian tissue to isolate preantral follicles from Zebu cows using a tissue chopper and to evaluate the follicular quality after isolation. Furthermore, it aims to provide information about the Zebu cow preantral follicle population and use this data (as a control) to evaluate the effectiveness of the tested isolation method. Testing eight different tissue sectioning size intervals, it was possible to conclude that the 125-microm-section interval is shown to be better than the intervals of 25, 50, 175 and 200 microm to isolate preantral follicles from Zebu cow ovaries. The 125-microm interval allowed the recovery of 26,050+/-1611 (mean +/- S.E.M.) preantral follicles per one-half ovary, while the number of preantral follicles in situ estimated by evaluation of histological sections was 35,288+/-2342 per one-half ovary. Thus, the mean (+/-S.E.M.) recovery rate (=[number of preantral follicles isolated/number of preantral follicles in situ in the same ovary] x 100) was 74.3+/-4.3%. The morphometrical analysis showed that Bos indicus preantral follicles are similar to B. taurus preantral follicles based on previous reports. In conclusion, this study showed that a simple, mechanical method can be used effectively to isolate a large number of intact preantral follicles from Zebu cow ovaries, with a high recovery rate.

Animals↗
PubMed1990

Improved morphologic characterization of atrial septal aneurysm by transesophageal echocardiography: relation to cerebrovascular events.

Transthoracic and transesophageal echocardiography was performed in 23 consecutive adult patients with an atrial septal aneurysm. In three patients with a cerebrovascular event the diagnosis was established by the transesophageal approach only. Interatrial shunting on transthoracic imaging with use of echocardiographic contrast imaging or Doppler color mapping, or both, was detected in 7 (41%) of 17 patients. On performing contrast imaging in combination with color flow mapping during transesophageal echocardiography, positive shunting was demonstrated in 15 (83%) of 18 patients. Echocardiographic identification of multiple fenestrations (n = 4) and thrombus within the aneurysm (n = 2) could be achieved for the first time by transesophageal ultrasound application. Cerebrovascular events occurred in 12 (52%) of 23 patients and were regarded as being definitely thromboembolic in 10 (43%); 8 (67%) of the 12 patients had repeated cerebral events. Except for mitral valve prolapse in one patient, no other potential cardiac source of embolism could be identified despite the use of transesophageal echocardiography. A thickening of the aneurysmal membrane greater than or equal to 5 mm was found in 9 (75%) of 12 patients with versus 3 (27%) of 11 patients without a cerebrovascular event (p less than 0.05); this proved to be the only significant difference between the two patient groups. The mechanism of embolization may be both primary thrombus formation within the aneurysm and paradoxic embolization through an interatrial communication as demonstrated by the findings in two patients. It is concluded that atrial septal aneurysm is a cardiac abnormality with thromboembolic potential. In patients with this lesion and a history of an embolic event, long-term anticoagulant therapy is indicated.

Echocardiography↗
PubMed2001

Morphological characterization of microspheres, films and implants prepared from poly(lactide-co-glycolide) and ABA triblock copolymers: is the erosion controlled by degradation, swelling or diffusion?

Erosion of biodegradable parenteral delivery systems (PDS) based on ABA copolymers consisting of poly(L-lactide-co-glycolide) (PLGA) A-blocks attached to polyethylene oxide (PEO) B-blocks, or PLGA is important for the release of macromolecular drugs. The degradation behavior of four types of PDS, namely extruded rods, tablets, films and microspheres, was studied with respect to molecular weight, mass, polymer composition and shape and microstructure of the PDS. For each device the onset time of bulk erosion (t(on)) and the apparent rate of mass loss (k(app)) were calculated. In the case of PLGA, the t(on) was 16.2 days for microspheres, 19.2 days for films and 30.1 days for cylindrical implants and tablets. The k(app) was 0.04 days(-1) for microspheres, 0.09 days(-1) for films, 0.11 days(-1) for implants and 0.10 days(-1) for tablets. The degradation rates were in the same range irrespective of the geometry and the micrographs of eroding PDS demonstrated pore formation; therefore, a complex pore diffusion mechanism seems to control the erosion of PLGA devices. In contrast, PDS based on ABA copolymers showed swelling, followed by a parallel process of molecular weight degradation and polymer erosion, independent of the geometry. The contact angles of ABA films increased either with decreasing PEO content or with increasing chain length of the PEO B-blocks. In summary, the insertion of a hydrophilic B-block leads to an erosion controlled by degradation of ABA copolymers, whereas for PLGA a complex pore diffusion of degradation products controls the rate of bulk erosion.

Biodegradation, Environmental↗
PubMed1994

Functional and morphological characterization of neuropathy induced with 5-lipoxygenase inhibitor CGS 21595.

Peripheral toxic neuropathy induced in rats with a 5-lipoxygenase inhibitor CGS 21,595 was characterized using special functional tests and pathological procedures. Functional tests included measurement of grip strength, landing foot splay, assessment of sensorimotor and autonomic functions and monitoring of motor activity. Pathological procedures consisted of perfusion fixation, embedding in plastic, teasing of isolated nerve fibers, and light and electron microscopy. Male and female albino rats received the test article orally by gavage on 5 days per week. To characterize the development of the lesion animals treated with 1000 mg/kg were examined and sacrificed at 2-week intervals until termination at 10 weeks. In a separate study, the dose-effect relationship was examined in groups of animals treated with 50,200 or 1000 mg/kg for 10 weeks. Neurotoxicity occurred only in animals treated with 1000 mg/kg and was first detected following 4 weeks of treatment. Although there were no overt clinical signs of neurotoxicity, functional examination detected a reduction of grip strength, increased landing foot splay and reduced motor activity. Neuropathological examination revealed peripheral segmental demyelination affecting predominantly the Schwann cells in the ventral spinal nerve roots. Owing to its unusual localization in the nervous system and to subtlety of functional signs, peripheral segmental demyelination represents a special diagnostic challenge in toxicological safety studies.

1-Naphthylamine↗
PubMed1998

Morphological characterization of lung and kidney lesions in C3H/HeJ mice infected with Leptospira interrogans serovar icterohaemorrhagiae: defect of CD4+ and CD8+ T-cells are prognosticators of the disease progression.

Neonates and young C3H/HeJ mice were highly susceptible to lethal infection with Leptospira interrogans serovar icterohaemorrhagiae. The main pathological changes were seen by light microscopy in the lung and kidneys of 3-week-old mice at 11 days after inoculation. Lung histological lesions included small and medium-sized vasculitis with fibrinoid changes, hemorrhages, moderate infiltrate of mononuclear inflammatory cells and fibrin thrombi. In the kidney there was mild to severe acute tubular necrosis associated with interstitial nephritis. Repair of damaged tubules in surviving mice was observed within 17 days after inoculation. Pathological findings of CD4+ and CD8+ cell-depleted mice were clearly more severe than that seen in untreated animals by 17 days after inoculation. Comparatively, CD4+/CD8+ cell-depleted mice had more marked lung and kidney lesions than in the CD8+ or CD4+ cell-depleted mice. A very high level of tubular alterations was seen in the kidneys of all treated groups. Increased degrees of interstitial nephritis also reflected the T-cell subsets depletion related events. Leptospires were clearly demonstrated by immunoperoxidase close to the sites of histological damage in all infected mice. C3H/HeJ mice represent a useful model for further studies in pathogenicity of leptospires and natural resistance of the host.

Animals↗