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At least 685 records · Page 38Linked to original sources
PubMed2005

Physiologic properties of small intestine submucosa.

BACKGROUND: Porcine small intestine submucosa (SiS) has been introduced as a bioprosthesis in herniorrhaphy. This study evaluates in vivo properties of SiS that would affect clinical use. MATERIALS AND METHODS: Twelve pigs underwent implantation of SiS (perforated and nonperforated) on the peritoneal surface. Gross characteristics were evaluated and random samples harvested for histological study at 2 (n = 6) and 8 (n = 6) weeks. Collagen deposition was determined by polarized microscopy. Neovascularity (percent area blood vessels, %A(bv)) was determined by immunohistochemical staining with a polyclonal CD-31 antibody. RESULTS: Perforated SiS had a higher density of capillary ingrowth compared with nonperforated at both 2 (5.6%A(bv) versus 1.4%A(bv), P < 0.05) and 8 weeks (6.0%A(bv) versus 1.6%A(bv), P < 0.05). Compared with 2 weeks, 8-week SiS had a larger proportion of incorporation (25% versus 83%, P < 0.05) and new collagen deposition (50% versus 94%, P < 0.05). Significant contraction was observed in SiS 8 weeks after implantation (preimplant area 98 cm2 versus post-implant area 50 cm2, P < 0.05). CONCLUSION: SiS incorporated well 8 weeks after implantation, with deposition of new collagen. Perforated SiS demonstrated a more rapid and greater amount of neovascularity. The degree of contraction suggests that larger areas of SiS should be selected for herniorrhaphy than would be necessary if synthetic materials were used.

Absorbable Implants↗
PubMed2005

Effect of the type of dietary fat on biliary lipid composition and bile lithogenicity in humans with cholesterol gallstone disease.

OBJECTIVE: The effect of the type of dietary fat on bile lipids and lithogenicity is unclear. This study compared the effects of two dietary oils that differed in fatty acid profile on biliary lipid composition in humans. METHODS: Female patients who had cholesterol gallstones and were scheduled for elective cholecystectomy were studied. For 30 d before surgery, subjects were kept on diets that contained olive oil (olive oil group, n = 9) or sunflower oil (sunflower oil group, n = 9) as the main source of fat. Gallbladder bile and stones were sampled at surgery. After cholecystectomy, duodenal samples were collected by nasoduodenal intubation during fasting and after administration of mixed liquid meals that included the corresponding dietary oil. Duodenal and gallbladder bile samples were analyzed for cholesterol, phospholipids, and total bile acids by established methods. Individual bile acid conjugates in gallbladder bile were measured by high-performance liquid chromatography. Gallstones were analyzed by semiquantitative polarizing light microscopy. RESULTS: Despite marked differences in the absolute concentration of biliary lipids and total lipid content, manipulation of dietary fat ingestion did not influence the cholesterol saturation or the profile of individual bile acids in gallbladder bile obtained from patients who had gallstones. All but one subject had mixed cholesterol stones. A cholesterol saturation index of hepatic bile in fasted cholecystectomized patients was similar in both dietary groups and indicative of supersaturation. In response to the test meal, the cholesterol saturation index decreased significantly in patients given the olive oil diet, reaching values lower than one at 120 min postprandially. In contrast, hepatic bile secreted by patients who consumed sunflower oil appeared supersaturated (cholesterol saturation index >1.5) throughout the experiment. CONCLUSIONS: Our results suggest that the type of dietary fat habitually consumed can influence bile composition in humans. In gallbladder, this influence was noted in the presence of more concentrated bile in the olive oil group. However, this was not translated into a modification of cholesterol saturation, which is likely due to the fact that cholesterol gallstones were present by the time the dietary intervention started. The finding that a typical postprandial variation in hepatic bile lithogenicity occurred only in olive oil patients was revealing. While keeping in mind the methodologic limitations of this part of the study, some gastrointestinal and metabolic mechanisms for this effect are discussed.

Adult↗
PubMed2004

Collagen fibres of the spontaneously ruptured human tendons display decreased thickness and crimp angle.

PURPOSE: To study collagen fibre thickness and crimp formation in healthy and ruptured human tendons. METHODS: The thickness, crimp angle and wavelength of the collagen fibres were analyzed by interference and polarization microscopy and the samples were studied by transmission and scanning electron microscopy in four different healthy human tendons (Achilles, Quadriceps, Biceps brachii and Extensor pollicis longus) and in 66 spontaneously ruptured tendons. RESULTS: In the normal (healthy) tendons, the diameter and crimp angle of the collagen fibres varied greatly between the four different tendons, the thickest fibres with the largest crimp angle being in the Achilles and Quadriceps tendons, whereas the Biceps brachii and Extensor pollicis longus, tendons that bear lighter strains but carry functions of high specificity, were found to have substantially smaller collagen fibres with lower crimp angle. Ruptured tendons had significantly smaller collagen fibre diameter than the normal tendons, the fibre diameter being -36% in comparison to their healthy counterparts in the Achilles tendons (P < 0.0001), -24% in the Quadriceps tendons (P < 0.0001), -37% in the Biceps brachii (P < 0.0001) and -14% in the Extensor pollicis longus (P = 0.10), respectively. Similarly, the crimp angle of the collagen fibres was also found to be lower in the ruptured tendons than in healthy, normal tendons. Further, the collagen fibres in the ruptured human tendons showed great variation in the crimp angle between the adjacent fibres and in the successive crimps of the same fibre. CONCLUSION: Our results show that spontaneously ruptured tendons display focal regions with decreased collagen fibre thickness, decreased crimp angle and disrupted crimp continuity, microscopic alterations that possibly result in reduced strength of the tendons being less resistant to tensile forces, and thus, place them at increased risk of ruptures.

Achilles Tendon↗
PubMed2006

Early development of reconstructed embryos after somatic cell nuclear transfer in a non-human primate.

To improve efficiency and assess variation in nuclear transfer techniques in non-human primates, we investigated the following factors: type of donor cell, interval between enucleation and cell injection, activation after electrical pulsing and cytokinesis inhibitors. An average of 16.4 oocytes were recovered from 91 retrievals; however, 15 (14%) additional retrieval attempts yielded no oocytes due to a failure of follicular stimulation. Oocyte maturation rates at 36, 38 and 40 h post-hCG were 46.2, 52.6 and 61.2%, respectively. The MII spindle could be seen clearly using polarized microscopy in 89.1% (614/689) of oocytes. Nuclei were seen in 42% of the NT couplets, 53% of those cleaved to the 2-cell stage and 63% of the 2-cell embryos developed to the 8-cell stage by Day 3. There was no difference in the occurrence of nuclear formation between couplets created using fibroblasts or cumulus cells, although embryos were more reliably produced with fibroblasts. The interval (2, 3 and 4 h) between enucleation and cell injection did not affect NT efficiency. Ethanol treatment after electrical pulses yielded more 2-cell NT embryos than did treatment with ionomycin, but the frequency of nuclear formation and development to the 8-cell stage was not different. Treatment of couplets with cycloheximide and cytochalasin B for 5 h after activation had no impact on NT efficiency.

Animals↗
PubMed2005

Comparative study of the efficacy of the topical application of hydrocortisone, therapeutic ultrasound and phonophoresis on the tissue repair process in rat tendons.

The purpose of this study was to compare the treatment efficacy of topical application of hydrocortisone, therapeutic ultrasound (US) and phonophoresis on the rat's Achilles tendon (tendo calcaneus) repair process after tenotomy. The two treated groups with US were made in a pulsed mode. The irradiation of US was performed at a frequency of 1 MHz and an intensity of 0.5 W/cm2 (SATA), for 5 min each session. The tendons were analyzed using the polarized light microscopy. The results showed that the treated group with the topical application of hydrocortisone has not been delivered transdermally and that the molecule of collagen responds to the ultrasonic stimulation. The treatment with phonophoresis was the more efficient method. These findings allow us to conclude that the US stimulates the acceleration of tissue repair processes and induces the transdermal delivery of hydrocortisone in a therapeutic concentration on the tendon.

Achilles Tendon↗
PubMed2002

Chirality, twist and structures of micellar lyotropic cholesteric liquid crystals in comparison to the properties of chiralic thermotropic phases.

Phase chirality in disk-like lyotropic cholesteric phases (Ch(D)) was investigated, which was induced by addition of center and axial chiral dopants to achiral lyotropic nematic host phases (N(D)). In a lyotropic nematic matrix of the disk-like N(D) phase in the ternary system hexadecyldimethylethyl ammonium bromide (C16Me2EABr)/water/n-decanol, a disk-like lyotropic cholesteric phase Ch(D) was induced by addition of the axial optically active compound R(-)-1,1'-binaphthalene-2,2'-diyl-hydrogen-phosphate (BDP). The helical twisting power (HTP) of the BDP is generally lower than the HTP value of inducing substances with center chirality as cholesterol, prednisolone and taurocholic acid. At constant composition of the N(D) phase, the helix lengths were determined in dependence on the BDP and steroid concentration by means of evaluation of the 'spaghetti-like' texture using polarizing microscopy. The reciprocal helix lengths are changing linearly with rising BDP concentration. The properties of the Ch(D) phase (textures, helix lengths, structural parameters of the micelles) induced by the chiral compounds and changed by the composition of host phases can give information to the mechanism of chirality transfer from the molecular level to that of the micellar aggregates and finally, to the liquid crystalline superstructure. Furthermore, the matrix influence of the N(D) phase on the helix formation was examined at constant BDP and steroid concentration. The structure in the Ch(D) phase was described in terms of micelle parameters. Finally, the inducing properties of a center chiral optically active compound such as cholesterol, prednisolone and taurocholic acid were compared with those of the axial chiral compound BDP. Last but not least, the situation of the theoretical and structural background for helix formation in liquid crystals, e.g. the explanation of chiralic transfer between micelles is analyzed and discussed. Two main conditions are necessary to build up the helix in the Ch(D) phase: the formation of H-bridges; and the existence of a specific chiralic interaction energy between neighboring micelles in the cholesteric superstructure.

Bromides↗
PubMed2000

Systemic amyloidosis presenting as a mass of the conjunctival semilunar fold.

PURPOSE: To report a case of systemic amyloidosis that presented as a mass of the plica semilunaris (semilunar fold) of the conjunctiva. METHODS: Case report. RESULTS: A healthy 56-year-old man developed a fleshy, hemorrhagic lesion of the semilunar fold of the left conjunctiva. Excisional biopsy revealed an acellular lesion of the conjunctival stroma that stained positively for Congo red and showed apple-green birefringence and dichroism with polarization microscopy. The diagnosis was amyloidosis of the semilunar fold of the conjunctiva. Subsequent evaluation disclosed systemic amyloidosis. The patient remains asymptomatic. CONCLUSIONS: Although conjunctival amyloidosis usually occurs as a localized lesion without systemic involvement, it can be the initial sign of systemic amyloidosis.

Amyloidosis↗
PubMed2000

Distribution and volumetric assessment of initial approximal caries lesions in human premolars and permanent molars using computer-aided three-dimensional reconstruction.

Serial sections from 21 extracted premolars and permanent molars, divided into three age groups (group 1, 10-19 years; group 2, 20-39 years; group 3, 50-69 years.), were viewed by polarized light microscopy for reconstruction of the caries lesions. The volumes of the lesional body and the transparent zone, and the volumes of early dentinal lesions were calculated; and an enamel demineralization index (EDI) and an enamel-dentine demineralization index (EDDI), representing the volumetric ratio of the body of the lesion to the translucent zone, and the body of the lesion to the volume of the early dentinal lesion, respectively, were determined. The method showed that there are three typical sites of individual initial caries lesions at the approximal surface: within the contact area, in the subcontact area, and in the cervical area. Volumetric assessment demonstrated a larger volume of the body of the lesion in older teeth with a smaller volume of the translucent zone relative to the lesional body. From these results it can be concluded that there are usually more than one individual initial caries lesions at the approximal tooth surface. Calculation of demineralization indices demonstrated different features for small lesions with pronounced transparent zones and for large lesions with small transparent zones. The computer-assisted three-dimensional reconstruction technique and the volumetric assessment are of value in investigations of the micromorphology and progression of natural caries lesions in permanent teeth.

Adolescent↗
PubMed2003

Volumetric assessment and quantitative element analysis of the effect of fluoridated milk on enamel demineralization.

OBJECTIVES: It was the purpose of this study to investigate the effect of milk and fluoridated milk on experimentally induced caries-like-lesions. MATERIALS AND METHODS: Twelve extracted impacted human molars were covered with wax leaving two 3 mm x 3 mm windows on the buccal and lingual surfaces and incubated alternating in demineralizing solution at pH 4.85 and in milk, F-milk, saline, and remineralizing solution, respectively. Afterwards serial ground sections were cut and investigated by polarization-light-microscopy (PLM) and SEM using EDX element analysis. RESULTS: The results showed increased thickness of the superficial layer in the F-milk samples. Quantitative element analysis revealed a significant increase in the fluoride content of the superficial layer and of the body of the lesion of the F-milk group. The body of the lesion of the F-milk group was less demineralized than in the other groups. CONCLUSION: From the results we conclude, that the parallel investigation by PLM, SEM combined with EDX quantitative element analysis is a powerful method to assess caries-like-lesion formation and that fluoridated milk has protective properties in inhibiting demineralization.

Animals↗
PubMed2001

Rational design of lipid molecular structure: a case study involving the C19:1c10 monoacylglycerol.

The phase properties of lipids have far-reaching consequences in membrane biology. Their influence ranges from domain formation in intact biomembranes to membrane protein reconstitution and crystallization. To exploit phase behavior in the spirit of rational design, it is imperative that the rules relating lipid molecular structure and liquid crystal or mesophase behavior be established. Phase behavior is quantitatively and concisely represented in the form of temperature-composition phase diagrams. A somewhat limited number of phase diagrams exists for the monoacylglycerols. The objective of the current study was to determine the quality of phase behavior prediction for a specific monoacylglycerol based on an analysis of the existing phase diagrams for related chain homologs. To this end, a phase diagram for the monononadecenoin (19:1c10)/water system was predicted in the temperature range from -15 degrees C to 120 degrees C and from 0% to 80% (w/w) water. The prediction was tested by constructing the corresponding phase diagram using low- and wide-angle x-ray diffraction, differential scanning calorimetry, and polarized light microscopy. The results show that the predicted and experimental phase diagrams agree remarkably well. They also highlight the need for additional phase studies of the type described to enlarge the data bank of phase diagrams and to strengthen the foundations of the rational design approach.

Calorimetry, Differential Scanning↗
PubMed2002

Biophysical and transfection studies of the diC(14)-amidine/DNA complex.

Liposomes of the synthetic cationic lipid, N-t-butyl-N'-tetradecylamino-propionamidine (diC(14)-amidine), efficiently ports DNA into mammalian cells in the absence of other (neutral) lipids. The compositional simplicity of this transfection mix makes it attractive from a formulation perspective. We have used low- and wide-angle x-ray diffraction and polarized light microscopy to characterize the thermotropic phase behavior and microstructure of diC(14)-amidine and of the lipid/DNA (circular plasmid, 5.4 kb) complex with a view to understanding the structure of the complex and its role in transfection. Upon heating, the lipid in buffer undergoes a lamellar crystalline (L(c), d(001) = 41.7 A)-to-lamellar liquid crystal (L(c)(alpha), d(001) depends on hydration and T) transition at approximately 40 degrees C. Sonicated lipid vesicles with a reported transition temperature of approximately 23 degrees C complex with DNA. Complex formation is complete at a DNA/lipid mole ratio (rho) of 0.8. Adding DNA to the lipid causes d(001) of the multilayered complex to drop from 52 to 49 A as rho rises from 0.03 to 1.64. The minimal DNA-DNA duplex separation observed is 26 A, consistent with the close packing of B-DNA. Lipid bilayers in the complex undergo a lamellar gel (L(c)(beta))-to-L(c)(alpha) (superscript c refers to complex) transition at approximately 23 degrees C. Transfection efficiency was maximized at rho = 0.4. The structure and transfection data combined suggest that densely packaged DNA in a net positively charged complex is essential for transfection.

3T3 Cells↗
PubMed1963

Birefringence of protein solutions and biological systems. II. Studies on TMV, tropocollagen, and paramyosin.

The intrinsic birefringences of TMV, tropocollagen, and paramyosin were calculated from flow birefringence measurements using the theory of Peterlin and Stuart. The values are -0.029, -0.029, and -0.030, respectively. The intrinsic birefringences of TMV and tropocollagen were measured as a function of the refractive index of the solvent in glycerol-water mixtures. In both cases the values were not constant and became less negative as the refractive index increased. Theoretical calculations showed that the large solvent effect could not be caused by a hydration shell of index different from that of the bulk solvent. It is concluded that either (a) the intrinsic birefringence calculated from the Peterlin-Stuart theory is incorrect or (b) the intrinsic birefringence depends markedly on the solvent. These results are of importance to the problem of quantitative polarized light microscopy since the separation of form and intrinsic birefringence contributions is based on the assumption that intrinsic birefringence is independent of solvent.

Biophysical Phenomena↗
PubMed1987

Uniformly oriented gramicidin channels embedded in thick monodomain lecithin multilayers.

Phosphatidylcholine multilayers, containing 20% water by total sample weight and gramicidin/lipid molar ratios up to 1:40 were aligned by low temperature annealing (less than 60 degrees C) and mechanical stressing. We were able to obtain large (greater than 80 micron thick X 40 mm2 area) monodomain defect-free multilayers containing approximately 10(17) uniformly oriented gramicidin channels. The alignment of lipid multilayers was monitored by conoscopy and polarized microscopy. The smectic defects, which appeared during the alignment process, were identified and dissolved. The incorporation of gramicidin into the multilayers in the form of transmembrane channels was indicated by its circular dichroic (CD) spectrum. A well-defined CD spectrum of uniformly oriented gramicidin channels was obtained. The oriented samples will allow spectroscopic studies of the ion channel in its conducting state and diffraction studies of the channel-channel organization in the membrane.

Circular Dichroism↗
PubMed1997

DNA length and concentration dependencies of anisotropic phase transitions of DNA solutions.

Critical concentrations for the isotropic to cholesteric phase transitions of double-stranded DNA fragments in simple buffered saline (0.1 M NaCl) solutions were determined as a function of DNA contour length ranging from approximately 50 nm to 2700 nm, by solid-state 31P NMR spectroscopy and polarized light microscopy. As expected for semirigid chains, the critical concentrations decrease sharply with increasing DNA length near the persistence length in the range from 50 to 110 nm, and approach a plateau when the contour length exceeds 190 nm. The biphasic region is substantially wider than observed for xanthan, another semirigid polyelectrolyte approximately twice as stiff as DNA, primarily because of low critical concentrations for first appearance of the anisotropic phase, C(i)*, in DNA samples > or =110 nm (320 base pairs) long. The limiting C(i)* for DNA > or =490 nm long is exceptionally low (only 13 mg/ml) and is substantially lower than the C(i)* of approximately 40 mg/ml reported for the stiffer xanthan polyelectrolyte. The much higher values of the critical concentrations, C(a)*, for the disappearance of the isotropic DNA phase (> or =67 mg/ml) are modestly higher than those observed for xanthan and are predicted reasonably well by a theory that has been applied to other semirigid polymers, if a DNA persistence length in the consensus range of 50-100 nm is assumed. By contrast, the broad biphasic region and low C(i)* values of DNA fragments > or =190 nm long could only be reconciled with theory by assuming persistence lengths of 200-400 nm. The latter discrepancies are presumed to reflect some combination of deficiencies in current theory as applied to chiral, strong polyelectrolytes such as DNA, and sequence-dependent variations in DNA properties such as flexibility, curvature, or interaction potential. The propensity of DNA to spontaneously self-order at low concentrations well in the physiological range may have biological significance.

Anisotropy↗
PubMed1997

Contrasting structure of the saphenous vein and internal mammary artery used as coronary bypass vessels.

OBJECTIVES: To report quantitatively on the three-dimensional layered organization of the collagen and smooth muscle component of the two most successful vessels for coronary bypass-the internal mammary artery (IMA) and the long saphenous vein (SV). Our aim was to provide an explanation for the differential structural stiffness of these two vessels (both functioning at arterial pressures in their new environment), and how they might be susceptible to endothelial thickening. METHODS: Eleven human saphenous veins and 23 internal mammary arteries were fixed at arterial distending pressure of 110 mmHg, and were sectioned in cross-section at 7 microns thickness. A subset of these was also sectioned tangentially. Measurements of the three-dimensional alignment of collagen and smooth muscle fibers within the vessel wall were made using polarized light microscopy and the universal stage attachment. Data were plotted and analysed using circular statistics. RESULTS: The IMA, structured like an elastic artery, is dominated by a media with discrete lamellae of wavy collagen and smooth muscle, aligned nearly circumferentially, with a low variability of alignment (mean circular SD 12 degrees). The SV is more variable in its size and structure, characteristically with a narrow circumferential media comprised mostly of collagen which is straightened and highly aligned at arterial pressures (mean circular SD 9 degrees). Circumferential collagen in the vein was often adjacent to longitudinal bundles of smooth muscle and collagen. CONCLUSIONS: The strikingly aligned structure of the SV complements the known high mechanical stiffness of this vessel when at arterial distending pressure. The high fraction of longitudinal muscle, in addition to the circumferential muscle cells in the SV make it vulnerable to any pre-implant surgical preparation, and to the cyclical luminal pressures and longitudinal strains characteristic for epicardial arteries.

Adult↗
PubMed2000

Can ERCP contrast agents cause pseudomicrolithiasis? Their effect on the final outcome of bile analysis in patients with suspected microlithiasis.

BACKGROUND: Microlithiasis has been implicated in the etiology of idiopathic pancreatitis and biliary-type pain in patients with intact gallbladders. Contrast injection at endoscopic retrograde cholangiopancreatography (ERCP) is used to confirm access into the bile duct and bile is also aspirated to look for microlithiasis. It is not known whether contrast agents contain crystals that could mimic true microlithiasis. METHODS: Four mL of 2 contrast agents (Hypaque and Omnipaque) were examined after centrifugation under polarizing microscopy. In the second part of the study, bile aspirated during ERCP with contrast injection was examined for microlithiasis and contrast pseudomicrolithiasis. RESULTS: Contrast agents exhibited pseudomicrolithiasis that mimicked calcium bilirubinate granules. Pathologists participating in the study were not aware of contrast pseudomicrolithiasis. Nine of twelve (75%) patients would have been reported as having microlithiasis and would possibly have undergone an unnecessary cholecystectomy. CONCLUSION: When bile collected during ERCP is to be examined for microlithiasis, it should be collected without contamination by a contrast agent. If this is not possible, pathologists should be aware that contrast can cause pseudomicrolithiasis.

Bile↗
PubMed2003

Frequency of biliary crystals in patients with suspected sphincter of Oddi dysfunction.

BACKGROUND: The passage of gallstones (macro- or microlithiasis) is theorized to play a role in inducing sphincter of Oddi dysfunction. This study examined the frequency at which biliary crystals are found in patients with suspected type II and type III sphincter of Oddi dysfunction. METHODS: A total of 85 patients (66 women, 19 men; mean age 38 years) with unexplained abdominal pain of suspected pancreatobiliary origin and no prior episode of pancreatitis underwent ERCP with sphincter of Oddi manometry and bile collection for crystal analysis. Eighty-one patients had a gallbladder in situ. No patient had evidence of stones or sludge on prior abdominal imaging. Sphincter of Oddi manometry was performed in standard retrograde fashion by using an aspirating catheter. Patients were classified by sphincter of Oddi dysfunction type by using a modified Hogan-Geenen classification system. Patients with type I sphincter of Oddi dysfunction were excluded. Bile was collected directly from the gallbladder (n=23) or common bile duct (n=62) after an infusion of 3.5 microg of cholecystokinin and was examined by light and polarizing microscopy for cholesterol crystals or calcium bilirubinate granules. RESULTS: The proportion of patients with crystals was 3.5% (3/85). Thirty-five patients (41%) had elevated biliary and/or pancreatic sphincter pressure (type II, 16; type III, 19), of whom one (3%) had cholesterol crystals. Fifty patients had normal sphincter pressure, of whom two (4%) had cholesterol crystals (p=0.6). All 3 patients with cholesterol crystals had a gallbladder in situ. Calcium bilirubinate granules were not found in any patient. CONCLUSIONS: Microlithiasis appears to be rare in patients suspected to have type II or type III sphincter of Oddi dysfunction. Evaluation of bile for crystals appears unproductive in this group of patients.

Adolescent↗
PubMed1996

Calcifying epithelial odontogenic tumours in small domesticated carnivores: histological, immunohistochemical and electron microscopical studies.

Histological, immunohistochemical and electron microscopical studies revealed one feline and four canine calcifying epithelial odontogenic tumours in 115 oral tumours over a 10-year period. The tumours consisted of islands and sheets of odontogenic epithelium of varying size within a stroma of fibrous connective tissues. The tumour cells were pleomorphic with variable amounts of eosinophilic cytoplasm and large hyperchromatic, polymorphic nuclei with prominent nucleoli. Clusters of keratinized tumour cells ("shadow cells") were frequently seen within the islands and sheets. The multiple spherules of homogeneous eosinophilic material stained positively with Congo red and Dylon stains and produced an apple green birefringence under polarization microscopy, indicative of amyloid. Mineralized foci were scattered throughout the tumour masses and in the homogeneous spherules. Immunohistochemically, the tumour cells reacted with anti-human keratin antibody, but not with anti-human vimentin or anti-chicken desmin antibodies. The homogeneous spherules did not react with anti-human keratin, anti-human vimentin, anti-chicken desmin, anti-amyloid A, anti-laminin or anti-human collagen (type I, III, IV) antibodies. Ultrastructurally, the cytoplasm of tumour cells was abundant and contained a large number of electron-dense bundles of tonofilaments. The homogeneous spherules consisted of fine filaments measuring about 10-12 nm in diameter.

Amyloid↗