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The existence of a new crystalline modification of the analgesic and antiinflammatory agent piroxicam was predicted. A model of the structure was derived from the crystal data of the alpha-modification. Lattice constants and molecular packing parameters were refined using X-ray powder diffraction data.
The title coordination compound has been synthesized by the reaction of HLaEDTA.7H2O with (formula; see text) in ethanol aqueous solution. The single crystal has grown from aqueous solution and has been characterized by IR, TG-DTA, X-ray powder diffraction, molar conductance, UV and 1H-NMR. The determination of its crystal and molecular structure shows that it crystallizes in space group P21/n with lattice parameters: a = 14.735A, b = 29.335A, c = 16.409A, beta = 99.24 degrees, v = 7009.30A3, z = 4, F(000) = 3488, molecular weight M = 1756.90, Dc = 1.665g/cm3. It has been refined by the full matrix least squares method to final discrepancy factor R = 0.096. The anion [La2(EDTA)2(H2O)4]2- turns out to be a dimer, in which each of the two EDTA4- ions is coordinated to a La3+ ion with five of its six coordinating sites and the remaining sixth one--the oxygen atom of carboxylis bridged to two La3+ ions, thus forming a parallelogrammic four-membered ring La2O2. The nine coordinations about each metal are completed by two water molecules. The average bond length is 2.560 A for La-O and 2.833A for La-N. Approximately, the dimer belongs to point group Ci with the centre of inversion at the centre of La2O2 parallelogram. The antitumor activity of the coordination compound was studied by observing its effect on the incorporation of 3H-TdR into DNA of leukemia (L7712) cells in vitro. The degree of inhibition reached 83.9% after exposing 2 X 10(5) cells per millilitre to 4 X 10(-5) mol/L of the compound for 24 h, being higher than those of its precursors.
The morphology and chemical composition of two subgingival calculus samples, which were composed of magnesium-whitlockite with a Mg/Ca molar ratio of approximately 0.1 as shown by X-ray powder diffraction, were analyzed semiquantitatively using energy-dispersive spectroscopy (EDS) combined with scanning electron microscopy (SEM). The Ca/P molar ratio values for 33 EDS-analyzed materials ranged from 1.24 to 2.03 with an average of 1.49, and the (Mg+Ca)/P molar ratio values ranged from 1.43 to 2.28 with an average of 1.63. The average Mg/Ca molar ratio was 0.10, a value very close to that obtained by X-ray diffraction analysis. The EDS-analyzed materials were grouped morphologically into three types; Type A materials were typical rhombohedral crystals, Type B were crystals of ill-defined form or small crystallite aggregations and Type C materials had a small granular structure or were amorphous. The values of (Mg+Ca)/P molar ratio for Type A ranged from 1.57 to 2.28 and averaged 1.81, those for Type B ranged from 1.43 to 1.56 and averaged 1.48, and those for Type C ranged from 1.46 to 2.06 and averaged 1.62. Type A crystals had higher molar ratios while Type B crystallites had values similar to that of whitlockite. Type C materials covered the ranges of both Type A and Type B. These results show that the materials resembling whitlockite morphologically did not have the (Mg+Ca)/P ratio of whitlockite and vice versa. This suggests that whitlockite crystals may substitute some ions for PO4 as well as Mg for Ca to a larger extent than thought previously, and that care is needed in the identification of these materials.
Sixty-four patients suspected radiologically to have gallstone disease were evaluated for clinical symptoms, physical findings and laboratory abnormalities. Fifty-three of them had ultrasound examination which confirmed the diagnosis in 52 (98.1%). An attempt was also made to identify possible predisposing factors. Sixty of these patients underwent cholecystectomies, with common duct exploration in 10 of them. On visual assessment at surgery, 96.6% of the stones were thought to be cholesterol in type. X-ray powder diffraction analysis of 30 different samples confirmed all to be cholesterol. We conclude that cholesterol gallstone disease, presenting with the usual clinical features, is a common health problem among Ethiopians. We feel that ultrasonography should be used more often for the diagnosis of this disease.
As crystals are important etiologic agents for disease, their accurate identification in tissues and body fluids is of utmost importance. This paper surveys the roles of crystals in disease process and outlines current analytical techniques for crystal detection and identification in bone tissues. The value of multiple correlated techniques is demonstrated including scanning electron microscopy, x-ray energy spectroscopy and powder diffraction analysis. The current feasibility of utilizing intermediate voltage scanning transmission analytical electron microscopy to integrate these analytical techniques on the same tissue sample is emphasized.
Polarizing microscopy, X-ray powder diffraction and differential thermal analysis can be used to detect small amounts of minerals which may occur in talcs as impurities. The characteristic features of chlorite, asbestos, magnesite, quartz and other minerals recognizable through these methods are described.
The preparation and characterisation of crystalline alpha-, beta- and gamma modifications of 3-cyan-6-methyl-5-(4-pyrid-4-yl)-1,2-dihydropyrid-2-on e are described. The thermic transformation of alpha- and beta-modification into gamma-modification was proved by thermogravimetric analysis (t.g.a.), differential scanning calorimetry (d.s.c.), IR and powder diffraction pattern. In dissolution behaviour no significant differences were found between the modifications.
In the present paper the crystallographic behavior of the carbamazepine modifications I, II and III were studied under various conditions by means of X-ray powder diffraction, IR-spectroscopy and differential-scanning-calorimetry. It was found that the crystal lattice of the carbamazepine modification I is relative stable to the applied pressure forms, whereas modification II under similar conditions undergoes a polymorphic transformation into carbamazepine modification III, the extent of which depends on compression pressure and storage time of the tablets. In the compression samples of carbamazepine modification III neither IR-spectroscopically nor X-ray-diffractionally an influence of the pressure could be found on growing up of the enantiotrophic modification I.
The correlative approach employing polarized light microscopy, x-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, selected area electron diffraction and energy dispersive x-ray microanalysis proves to be very useful in identifying fictitious calculi and genuine human calculi with foreign body nuclei. The common artifacts as reported in the literature and observed also by us were minerals, vegetable and plant seeds, cereals, sand grains and sea shell fragments. Two interesting cases involving foreign body nuclei have been reported: one urinary calculus containing a piece of plastic-coated titanium foil in the center; one nasal calculus with a nut as a nucleus. Another common cause for foreign body nucleation is iatrogenic: intrauterine devices, catheters, suture materials and even surgical staples have been reported in the literature to be potent nidi for calculus formation. These cases remind us of the important fact that our body fluids are supersaturated with respect to calcium phosphates and occasionally to other compounds. Hydroxyapatite crystals are readily nucleated by foreign bodies. Whitlockite is involved if the fluid Mg/Ca ratio is in a suitable range, brushite if the fluid is acidic and struvite if there is urea-splitting infection. In urine and other fluids, calcium oxalate and uric acid crystals contribute to the calculus growth.
In the present paper the interconversion behavior of the carbamazepine modifications I, II and III under various grinding conditions (variation of milling aggregates, milling times and frequencies) were studied. Mechanical treatment of different crystal forms led to a uniform grinding product, which is characterized crystallographically as modification III. The kinetic of phase transformations were determined by means of various quantitative methods such as a IR-spectral, a X-ray-powder diffractional and a thermoanalytical one. The results obtained by different analytical methods accorded quite well.
All physico-chemical techniques used in the analysis of urinary calculi have inherent advantages and limitations. Although x-ray powder diffraction can identify constituents unambiguously, certain minor components can be missed. Infrared spectroscopy is more sensitive but band assignment at low concentrations is difficult. Scanning electron microscopy together with energy dispersive x-ray analysis permits the simultaneous investigation of morphology and chemical microstructure. However, microanalysis of elements lighter than sodium is not possible and constituents are prone to irradiation damage. With the electron microprobe, minor constituents can be detected but tedious sample preparation procedures are required. Transmission electron microscopy is extremely useful in determining constituent inter-relationships and ultrastructure but ultramicrotomy is very difficult. Thermal gravimetric analysis gives quantitative information easily but does not satisfactorily distinguish between struvite and brushite. In an attempt to assess the accuracy of chemical analyses, 62 calculi were investigated applying several chemical tests. Those for Mg2+, PO4(3-), NH4+ and uric acid proved highly reliable while that for Ca2+ often yielded an incorrect result. The test for oxalate was totally unsatisfactory. Investigators of stone composition and structure should include x-ray diffraction (or infrared spectroscopy) and scanning electron microscopy as their methods of first choice. In addition, chemical or thermogravimetric analyses should be utilized in an auxiliary capacity.
Three polymorphic forms of 1-methyl-2-nitro-5-vinylimidazole, a potential antimicrobial drug, have been isolated and characterized by thermomicroscopy, differential scanning calorimetry, infrared spectroscopy and X-ray powder diffraction. On the basis of some infrared bands, the hypothesis has been made that the different packing of forms I and II was due to the existence of the molecule in two different conformations in the two forms. The direct confirmation of the hypothesis has been sought by X-ray diffraction of single crystals, but a suitable crystal was obtained only for form II. Form II is orthorhombic, space group Pbca, with unit-cell dimensions: a = 13.05, b = 10.83, c = 10.21 A; Z = 8. From the X-ray analysis, carried out by direct methods, the molecule is planar and the vinyl group is cisoid to the heterocyclic CH group. Then, the existence of the molecule as transoid conformation in form I still remains a hypothesis.
Nine even-numbered saturated (C4 to C20) and two unsaturated (C18:1, C18:2) cholesterol alkyl ethers were studied by differential scanning calorimetry, polarizing microscopy, and X-ray powder diffraction. Seven of the nine saturated ethers examined melt into stable liquid crystal mesophases. Mesophase transition temperatures vary over a much narrower range than in cholesterol esters and are lower than those of corresponding esters. Polarizing microscopy and X-ray diffraction show structural similarities between cholesterol ethers and esters. Since cholesterol ethers behave similarly thermotropically to cholesterol esters, they may serve as suitable nonmetabolizable analogues for cholesterol esters in biological systems.
Microdissection and scanning electron microscopy were used to study temporal bone specimens from a newborn infant with Potter's syndrome. The 34-year-old mother of the infant had juvenile-onset rheumatoid arthritis and she took prostaglandin inhibitors (aspirin, indomethacin, and Clinoril) during pregnancy. Autopsy findings included bilateral renal dysgenesis, pulmonary hypoplasia, abnormal facies with low-set ears, and bilateral cataracts. The infant's left external ear canal was stenotic and the left tympanic anulus was narrowed. Otherwise, both middle ears, as well as the sensory structures of the cochleae and semicircular canals, were normal. The saccular and utricular muculae on the right were entirely devoid of otoconia, although they were covered by gelatinous otoconial membranes which appeared normal. On the left, the maculae were covered by thin layers of flat, lenticular crystals 2 to 10 mu in diameter. X-ray powder diffraction analysis showed these aberrant otoconia to be composed of calcium carbonate in the form of vaterite. No abnormalities of the neuroepithelia or macular nerve supply were found in either ear.
CHINOIN-137 consists of indometacin and beta-cyclodextrin in a 1 : 2 molar ratio. solid phase analytical techniques, as thermal analysis, mass spectrometry and X-ray powder diffraction do not support the existence of a well-defined crystalline complex. However this product dissolved in water more readily and results in a higher indometacin concentration than indometacin itself. The formation of an inclusion complex with a reasonable stability in aqueous solution was proved by diffusion tests and chiroptical properties. Following oral administration of CHINOIN-137 to rats, higher blood levels (by about 25%) of indometacin can be achieved than with the uncomplexed drug. A significant difference was observed in the absorption of 14C-labelled indometacin and its cyclodextrin complex by "in loco" techniques in the small intestines of anaesthetized rats: from indometacin 56%, from the complex 68% of the activity was resorbed within 10 min.
We studied articular disks and endoarticular loose bodies taken from patients suffering from different types of temporomandibular joint (TMJ) pathology. The scanning electron microscopy (SEM) analysis of the disks and the endoarticular loose bodies was followed by a chemical-compositional analysis using an energy dispersive spectrometer (EDS) and by characterization of the crystalline phases by X-ray powder diffraction (XRD). The articular disks were composed of a central radiopaque area lacking any evident structural features, surrounded by compact bundles of collagen fibers. EDS and XRD analyses showed that endodiscal radio-opaque areas were hydroxyapatite. By SEM, we observed a fibrous network only in circumscribed areas of the endoarticular loose bodies. The chemical-compositional analysis showed that the loose bodies were composed of calcite (CaCO3). The results of this investigation, along with the clinical history of the patients, allow us to formulate some hypotheses regarding the etiopathogenesis of these structural anomalies. The endodiscal calcifications could be the result of a chronic inflammatory process that produces displastic alterations of the articular disk. Moreover, an acute inflammatory process with modifications in the mechanisms of the synovial fluid turnover seems to be the event that leads to the formation of endoarticular loose bodies.
The polymorphism of rifamexil, a rifamycin derivative, has been investigated by thermomicroscopy, differential thermal analysis (differential scanning calorimetry-thermogravimetry), IR spectroscopy, and X-ray powder diffraction. Two crystalline forms, an amorphous material, and three solvates have been studied. The crystal structures of two solvates have also been determined by single-crystal X-ray techniques. Although the overall conformation of rifamexil is very similar in the two compounds, marked differences occur between the two crystal packings, due to differences both in the mutual orientation of the molecules and in the rifamexil-solvent interactions. Multivariate statistical methods have been used to identify the principal structural parameters determining the biological activity of the rifamycins.
Pentamidine isethionate is a lyophilized antiprotozoal drug. Its solutions, when lyophilized, have been found to exhibit a range of properties that depend on its concentration and the manner in which it is allowed to freeze. These properties were examined by Differential Scanning Calorimetry (DSC), freeze-drying microscopy and X-ray powder diffraction. In DSC studies, the drug exhibited eutectic behavior with a eutectic temperature of -2.8 degrees C. Freeze-drying microscopic examination of a sample of solution after cooling at about 1 degrees C/min showed that the sample dried with retention up to -4 degrees C, where melting was observed. By using the appropriate drug concentration and manipulating the freezing stage, crystallization of the drug from solution could be induced during cooling to yield a crystalline end-product.