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Results for “Microscopy, Polarization”

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At least 343 records · Page 19Linked to original sources

PubMed2004

Preparation and evaluation of floating risedronate sodium Gelucire 39/01 matrices.

Incorporation of bisphosphonates in the lipid reduces gastric irritation. Only gastric retention with sustained release allows the drug to reach the duodenum and jejunum and improves the availability of bisphosphonates. Risedronate sodium and Gelucire 39/01 floating matrices were prepared using melt solidification. The sustained release floating matrices were evaluated for in vitro and in vivo floating ability and in vitro drug release. Ageing of the matrices was studied by differential scanning calorimetry, hot stage polarizing microscopy, scanning electron microscopy and in vitro drug release. Ageing causes changes in the crystal structure of Gelucire, which is responsible for an increase in drug release.

Adult↗

PubMed2005

Acute felbamate overdose with crystalluria.

A 3-year-old child developed vomiting, ataxia, and crystalluria after ingestion of approximately 232 mg/kg of felbamate elixir. High-powered polarization microscopy of the urine revealed sharp, needle-like crystals. The analysis of the urine crystals showed unchanged felbamate (80.9%), monocarbamate felbamate (18.8%), and trace amounts of mercapturic acid conjugates of the metabolite 2-phenylpropenal (0.1%). The serum felbamate level 15 h after ingestion was 138 mg/L. Crystalluria and hematuria resolved with intravenous fluid therapy, and the child recovered within 24 h.

Anticonvulsants↗

PubMedDate not supplied

[Microscopic lesions of the myocardium in acute coronary heart disease].

A statisticomathematical analysis of microscopic changes in the myocardium has established pathognomonic and differential-diagnostic morphological signs for diagnosis of acute ischemic heart disease--acute coronary failure and acute myocardial infarction at the prenecrotic stage. The results of chromotrop 2B water blue staining of histological preparations and polarization microscopy were compared.

Acute Disease↗

PubMedDate not supplied

[The characteristics of the chemical composition and structure of urinary stones and their prevalence in the cities of Moscow, Berlin and of the Kirghiz SSR].

The authors studied the features of urolithiasis in three different geographical regions: Moscow, the Kirghiz SSR, and Berlin from the findings of examination of the composition and structure of uroliths removed by operation or passed spontaneously, (602 concrements from Moscow, 10,000 from Berlin, and 127 from Kirghizia). X-ray diffraction measurement, infrared spectrophotometry, and polarizing microscopy were conducted to analyze the composition and structure of the stones. Complex biochemical examination was carried out in patients from Moscow and Kirghizia. According to the results of the study, the following features of urolithiasis are common in the studied regions: (1) prevalence of oxalate lithiasis on the whole, which points to the principal role of metabolic factors in lithogenesis; (2) approximately similar amounts of apatite carbonate crystals in the uroliths; (3) certain similarity in composition of concrements from Berlin and Kirghizia. The most essential differences are: (1) the frequency of renal oxalate stones is highest in Berlin and lowest in Moscow. The prevalent types of calcium oxalate stones are: whewellite of concentric structure (linked with hyperuricemia) in Kirghizia; whewellite of small randomly orientated crystals (linked with hypercalciuria) and stones with signs of transformation of weddellite to whewellite in Moscow; (2) lesser distribution of phosphate lithiasis in Berlin than in Kirghizia and particularly in Moscow. Prevalence of struvite crystals in stones from Moscow, the formation of which is linked with the vital activity of Proteus and E. coli; (3) higher distribution of urate lithiasis in Moscow and particularly in Kirghizia where significant metabolic risk factors of lithogenesis were revealed.

Berlin↗

PubMed1990

[Quartz crystals in the skin as a cause of progressive systemic scleroderma].

There is a close correlation between the systemic sclerosis and the exposure to crystalline silica in the GDR. The silica content was investigated in the skin of the patients. Silica particles were found using phase-contrast and polarizing microscopy. The size of the crystals varied from 1 to 90 micrometer. Below a silica content of 10% in the dust it is unlikely that systemic sclerosis is developing.

Biopsy↗

PubMed1990

Analysis of urinary calculi by infrared spectroscopy.

In the past 4 years, we used infrared spectroscopy to analyze 728 urinary calculi. The most common component of pure urinary calculi was calcium oxalate (whewellite and weddellite) 8.65%, followed by calcium phosphate (carbonate apatite, brushite and amorphous calcium phosphate) 6.87%, uric acid 5.91% and struvite 2.75%. The majority of urinary calculi had mixed components: whewellite/apatite 28.98%, weddellite/apatite 24.31% and whewellite/weddellite/apatite 14.42%. Only 3 cystine stones were found (0.41%). Good correspondence (82.7%) was noted when the results of 110 urinary calculi analyzed by infrared spectroscopy were compared with the results of polarization microscopy. The advantages and disadvantages of infrared spectroscopy are also discussed.

Adolescent↗

PubMed1990

[Studies on the occurrence of texture types in calcium oxalate urinary stones].

A review of texture types of calcium oxalate calculi and a pattern of 4 basic texture types was presented. A method of texture classification as a part of the routine polarization microscopy urinary calculus analysis was developed. Thereby a representative material could presented on the distribution of texture types. A connection between pathological urinary parameters and the texture type was demonstrated.

Calcium Oxalate↗

PubMed1990

Neurofibrillary tangles in some cases of dementia pugilistica share antigens with amyloid beta-protein of Alzheimer's disease.

Formalin-fixed, paraffin-embedded temporal lobe sections from eight former boxers' brains were examined using an immunohistochemical method with antibodies to amyloid beta protein. In accord with recent observations in Alzheimer's disease, significant numbers of beta-protein immunoreactive neurofibrillary tangles (NFT) were observed in three cases. Most of these immunoreactive NFTs appeared to be tombstone tangles, although not all such tangles were stained. This immunoreaction was completely abolished by preincubation of antibodies with synthetic beta-protein peptides, and the identity of the immunostained NFTs was confirmed by polarization microscopy of sections counterstained with Congo red. However, it is not yet clear if the beta-protein antigens are, in fact, an integral part of paired helical filaments. These observations, together with our recent finding of beta-immunoreactive plaque-like lesions in dementia pugilistica, also emphasize the many similarities in pathology between this condition and Alzheimer's disease.

Adult↗

PubMed1989

Myocardial fibrosis in nonhuman primate with pressure overload hypertrophy.

Characteristics of pressure overload hypertrophy are known to include an accumulation of collagen (or fibrosis) and a biochemical remodeling of fibrillar type I and III collagens. The corresponding structural nature of myocardial fibrosis is less clear. This light morphologic study was undertaken to address this issue in the hypertrophied left ventricle of the nonhuman primate with experimental hypertension. For this purpose, the picrosirius red technique and polarization microscopy were used to examine the myocardium during the evolutionary, early, and late phases of established hypertrophy corresponding to 4, 35, and 88 weeks of experimental hypertension. Evidence of increased thin perimysial fiber formation, together with collagen fiber disruption and edema at 4 weeks of hypertrophy, was found when the chamber volume to left ventricular mass ratio was reduced. After 35 weeks, when this ratio was again normal, a greater number of intermuscular spaces contained both thick and thin perimysial fibers. In addition to this interstitial fibrosis, a reactive fibrosis consisting of a meshwork of thick and thin perimysial fibers was seen extending over muscle fibers. Finally, at 88 weeks, this fibrous meshwork had encircled muscle and there now was evidence of cell necrosis. The accompanying replacement fibrosis consisted of yet another distinctive orthogonal grid of thick and thin collagen fibers. Thus, a continuum of fibrillar collagen remodeling was seen in pressure overload hypertrophy in the nonhuman primate myocardium. Structurally distinct patterns of myocardial fibrosis were recognized based on the alignment of perimysial fibers with muscle that may explain the cellular remodeling and altered mechanical behavior of the concentrically hypertrophied myocardium.

Animals↗

PubMed1989

[The effects of the CO2 laser on human dentin and cementum].

Polarizing microscopy, scanning electron microscopy and X-ray diffraction analysis have been used to study the effects of the radiations of a CO2 laser equipment on the dentine and cementum of sound human permanent teeth. The typical lesions induced in dentine and cementum differ only lightly because of the different composition of the tissues. They assume a crater-like aspect and show structural alterations, less and less severe when moving away from the beam focal center. The morphological analysis of the tissues, which loose their organic components through combustion, suggests that such lesions are the consequences of a very fast overheating followed by a fast cooling. X-ray diffraction analysis shows that the hydroxyapatite of the tissues submitted to the thermic stress does not undergo phase transformation, which means that the temperatures remain lower than 1200 degrees C.

Dental Cementum↗

PubMedDate not supplied

[Determination of the composition of the concretions in patients with nephrolithiasis by metabolic indices].

The authors considered an important problem of in vivo verification of urolith composition as specifying the choice of drug treatment and prevention of urolithiasis. 84 nephrolithiasis patients were allocated to 4 groups according to their concrement compositions (after spontaneous or surgical removal): 23 patients with urate calculus, 19 with oxalate, 20 with phosphate and 22 with oxalate-phosphate concrements. Polarizing microscopy, x-ray structural analysis and infrared spectrophotometry were employed for verification of calculi composition. Biochemical assay was used for the assessment of serum and circadian excretion of calcium, phosphates, sodium, potassium, uric acid, oxalates and uroacidimetric values. The findings were subjected to discriminant computed analysis which resulted in 6 linear computable functions defining 4 selective groups with regard to biochemical blood and urine data. The aforementioned functions were used in diagnostic routine for the in vivo assessment of calculous composition in 26 controls. In 61.5 per cent of the patients the diagnosis was confirmed, in 34.6 per cent it was verified, and only in 3.9 per cent the diagnosis turned to be erroneous.

Diagnosis, Computer-Assisted↗

PubMedDate not supplied

[Influence of low-intensity laser radiation on the formation of liquid crystalline structures in a solution of glycoproteins].

Liquid-crystalline structure formation in glycoprotein solutions irradiated by helium-neon laser in the presence of hydrogen peroxide was observed by both polarizing microscopy and spectrophotometry. High molecular weight (2.10(6) Da) and heavily glycosylated (about 80%) glycoprotein was isolated from the mucus layer of pig small intestine. Remarkable changes of both optic parameters of the solutions and the morphology of liquid-crystalline structures were detected in irradiated samples compared to the non-irradiated ones.

Crystallization↗

PubMed1988

The influence of local anesthetics on the gel-liquid crystal phase transition in model dipalmitoylphosphatidylcholine membranes.

The influence of local anesthetics (LA): tetracaine, lidocaine, cocaine, dibucaine and heptacaine derivatives on the gel to liquid crystalline phase transition temperature (Tc) of model dipalmitoylphosphatidylcholine (DPPC) membranes was studied using electron spin resonance (ESR) and polarization microscopy methods. The decrease of Tc in the presence of anesthetics (delta Tc) was found to be dependent on the [DPPC]/[H2O] molar ratio at constant [LA]/[DPPC] molar ratio. Hence, the parameter alpha = delta Tc/[( LA]/[DPPC]) in dependence on [H2O]/[DPPC] was extrapolated to zero concentration of water and compared with biological efficiency.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed1989

The fibrillar nature and structure of isoproterenol-induced myocardial fibrosis in the rat.

A study of isoproterenol-induced (1 mg/kg) myocardial fibrosis in the rat was undertaken, taking advantage of the differential colorization provided by thick and thin collagen fibers to picrosirius red and polarization microscopy. The objective was to monitor the sequence (day 1, 2, 3, 4, and 8), fibrillar composition, and nature of isoproterenol-induced collagen remodeling, which was found previously to adversely influence myocardial stiffness. The following were found: 1) a distortion and widening of intermuscular spaces on day 1 that was accompanied by the disruption of collagen fibers; 2) by day 2, these spaces were closing and a new fibrillar collagen network had appeared consisting primarily of thinner collagen fibers that crossed over muscle fibers; 3) the new fibrillar network took on a clear crisscrossing pattern on day 3 and 4 as an ever-increasing number of thicker fibers became entwined perpendicular to the thinner fibers; and 4) by day 8, a dense mesh of thick and thin collagen fibers had formed to encircle muscle while a greater number of intermuscular spaces, previously devoid of collagen, were now filled with thicker and thinner collagen fibers. Thus, isoproterenol-induced myocardial fibrosis is initiated by the appearance of interstitial edema and fibrillar collagen disruption and is followed soon thereafter by the formation of thinner collagen fibers that extend across muscle fibers and into which thicker collagen fibers become entwined in a crisscrossing pattern. Once formed, this mesh of collagen fibers encircles cardiac muscle. This pattern of fibrous tissue formation may entrap and isolate myocytes so that the mechanical behavior of muscle and the intact myocardium becomes abnormal.

Animals↗

PubMed1988

[Structural research on the membranes and adjacent layers of erythrocytes during the production of erythrocyte ghosts].

Using the polarization microscopy and X-ray crystal analysis it has been shown that the ordered structure is destroyed in membranes and adjacent layers of erythrocytes in the course of erythrocyte ghost preparation. These changes are accompanied by quenching of the birefringence which completely disappears in erythrocytes ghosts. The intensities of reflections in X-ray patterns are essentially decreased and the interlayer distances are changed.

Cell Fractionation↗

PubMedDate not supplied

[Formation of the regular, optical isotropic phase of low molecular weight DNA molecules modified by cis-dichlorodiammineplatinum].

It is shown that condensation of DNA molecules of low molecular mass (less than 1 X 10(6) in NaClO4-containing solution of poly(ethylene glycol) brings about formation of cholesteric liquid crystal phase; pattern of this phase is presented. It has been found by means of X-ray analysis and polarization microscopy that at certain level of modification with cis-dichlorodiammineplatinum (II) the DNA molecules instead of cholesteric structure form an ordered optically isotropic phase. The problem about the causes of the formation of such phase and about the pattern of spatial organisation of adjacent DNA molecules in it remains open.

Animals↗

PubMed1984

Mineralization of developing teeth.

The distribution of some essential elements and mainly Ca & P in mineralizing matrices of enamel, dentine and predentine and in contiguous cellular strata of developing mouse molars was studied by electron probe analysis, supplemented by polarization microscopy. Distribution gradients for Ca, P, & Ca/P were noted in the matrices. In the early stages of mineralization of enamel and dentine (predentine) Ca/P ratios were low suggesting the presence of either amorphous forms of calcium phosphate or protein bound calcium. Calcium concentrations in odontoblast and ameloblast strata were notable. Elevated values were recorded in the ameloblast layer of the most mature stage (14 days). Sulfur concentration in early enamel exceeds by tenfold that of mature enamel largely due to loss of methionine. The substantial levels of sulfur in predentine are barely detectable in dentine probably due to the loss of sulfated glycosaminoglycans. The mineralization of the negatively charged matrices of enamel and dentine is associated with the loss of water, changes in composition and in the state of aggregation. The accumulation of calcium in crystalline and other forms can be explained by the conditions of the Gibbs-Donnan equilibrium.

Animals↗

PubMed1984

[Ultrastructure of the peri-infarcted zone of the myocardium].

Light, electron and polarization microscopy techniques were employed to examine the myocardium in 26 dogs under experimental occlusion of the anterior descending branch of the left coronary artery in its middle third from 2 hours to 1 month. The periinfarcted zone is thought to be adjacent to the zones of ischemia and myocardial infarction and to be represented by a zone of lipid infiltration of cardiomyocytes in which the contraction lesions and foci of intracellular myocytolysis are demonstrable. It is shown that the increasing of the volume of the myocardial necrotic tissue under coronary occlusion is accounted for by progressive microthrombosis leading to circulatory disorders and necrosis of lipid infiltrated cardiomyocytes in the periinfarcted zone. The pathological intracellular regeneration in the atrophied cardiomyocytes of the periinfarcted zone was discovered to contribute to hypertrophy of myocytes with abnormal myofibril orientation. Studies of the periinfarcted zone hold promise from the standpoint of influencing the metabolism and intracellular regeneration of this zone cardiomyocytes, that mainly determines the reparative regeneration of the myocardium in ischemic necrosis.

Animals↗