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PubMed1975

Brain calcification in a case of acute lymphoblastic leukaemia.

Cortical calcifications, ween on X-ray in the brain of achild suffering from leukaemia, were submitted to morphological and chemical analysis. The morphology was studied by a combination of low teperature ashing and microscanning. The calcification principally affected axons and capillary walls and consisted of spherules amalgamated into hollow cylinders. The results of chemical analysis of the calcified material were compared and structure of both types of calcification were similar, but the Mn concentration washigher in case of Fahr's disease. X-ray diffraction showed that the calcification consisted of amorphous calcium phosphate and acid calcium orthophosphate, most probably precursors of hydroxyapatite..

Brain↗
PubMed1977

An ultrastructural study of the calcifications in calcifying odontogenic cysts and odontomas.

The calcifications associated with the epithelium of the calcifying odontogenic cyst and odontoma were studied ultrastructurally and found to be of three types: (1) spherical calcifications which form on ghost cells and which therefore are dystrophic, (2) spherical calcifications which appear to be dysplastic enamel, and (3) irregularly shaped, diffuse calcifications which form on a collagenous matrix and appear to by dysplastic dentin or cementum.

Calcinosis↗
PubMed1984

Calcification in the stylohyoid ligament.

This article describes the incidence of calcification in the stylohyoid ligament in a sample of the patient population of the University of Mississippi School of Dentistry. The records of 479 patients were reviewed, with particular attention given to the panoramic radiograph. The patients ranged in age from 4 to 78 years, with a mean age of 29. There was a sharp increase in incidence of calcification during the first three decades of age from 45.3% in the first decade to 86.2% in the third, with a gradual increase from the fourth to the seventh decade (87.3% to 92%). The eighth decade, represented by nine patients, showed an incidence of 100%. There appears to be no race predilection for calcification, a slight sex predilection for females, and an age incidence that seems to support both the developmental and degenerative theories of etiology of calcification in the stylohyoid ligament.

Adolescent↗
PubMed1987

Ultrastructural study of initial calcification in the rat subcutaneous tissues elicited by a root canal filling material.

The ultrastructural aspects of initial calcification in the rat subcutaneous tissues elicited by the root canal filling material Vitapex, made up of calcium hydroxide and iodoform with the addition of silicone oil, were studied by means of electron microscopic and cytochemical techniques. The embedded paste caused heterotopic calcifications. These were divided into two types: dystrophic calcification and matrix vesicle calcification which resembled that of bone tissue. These data suggest that Vitapex may be an excellent root canal filling material for differentiation of osteoblasts or cementoblasts from mesenchymal cells in the periodontal ligament.

Animals↗
PubMed1988

Response of the cubital vein to occlusion and calcification of the abdominal aorta in patients with chronic renal failure on maintenance hemodialysis.

Dysfunction of vascular endothelial cells and accelerated calcification of the abdominal aorta were found in patients on maintenance hemodialysis. Indicators of vascular wall function, expressed as the amount of plasminogen activator and von Willebrand factor released during venous occlusion, suggested that the cubital venous wall in patients has normo- or hyper-responsiveness to occlusion. Calcification of the abdominal aorta on CT scan image was observed in most of patients including those of the ages of twenties years. The mean aortic calcification index (ACI), as an indicator of organic changes in vascular wall, was significantly higher in dialysis patients than in the nondialysis subjects. However, the mean values of indicators for vascular wall function decreased and ACI increased, as the period of treatment with hemodialysis became longer. A significant negative correlation was found between the mean ACI and most indicators of vascular wall function. The function of cubital vein was suggested to decrease in association with the progress in mural calcification of the abdominal aorta. We conclude that the alteration of the coagulation-fibrinolysis system induced by repeated hemodialysis may result from and continue to exacerbate endothelial damage, the consequence of which may be atherosclerosis.

Adult↗
PubMed1984

Cervical radiculomyelopathy due to calcification of the ligamenta flava.

Three cases of cervical radiculomyelopathy caused by calcification of the ligamenta flava of the cervical spine are reported. A review of the literature yielded 13 cases of calcification of the cervical ligamenta flava with findings similar to those in our cases. Specifically, we observed that 1) all patients were more than 50 years of age; 2) most were female; and 3) the calcifications appeared consistently as oval nodules, located symmetrically and paramedially in and around the region of the fifth cervical vertebra. Such characteristic similarities in both clinical and radiologic features are important in considering the etiology of calcification of the cervical ligamenta flawa.

Aged↗
PubMed1977

Primary amyloidosis of urinary bladder and ureter: cause of mural calcification.

Primary amyloidosis is seen in the absence of predisposing disease. It may affect most organs in the body, including the collecting system of the urinary tract. Submucosal calcifications have been described in the renal pelvis and may be pathognomonic for primary amyloidosis of the renal pelvis. We have been able to demonstrate similar submucosal calcifications in the ureter and bladder. The differential diagnosis of submucosal calcification of the distal ureter and bladder must include bilharziasis and tuberculosis. With the recognition of submucosal calcifications, diagnosis of the underlying disease may be readily made. An illustrative case is presented.

Amyloidosis↗
PubMed1981

Possible causes for the calcification of glutaraldehyde-treated tissue heart valves and blood contacting elastomers during prolonged use in medical devices: a physico-chemical view.

Calcification of glutaraldehyde-treated porcine tissue heart valves (xenografts) is not a unique phenomenon but characteristic of a variety of synthetic elastomers and to a lesser extent of non-elastomeric polymers. The main commonality between them is their relative flexibility, permeability, and porosity, and differing capability to adsorb and to absorb various blood components. Although the possibility of biochemical factors involving calcium homeostasis and vitamin K-dependent protein carboxylation as recently proposed by others should not be ignored, it should be noted that calcification of synthetic elastomers has been reported with or without continuous anticoagulation with coumarin derivatives. This paper presents a physico-chemical view showing that despite the observed calcifications with a small number of xenograft valves, their otherwise impressive performance in the physiological environment is due to a significant extent to thermodynamic, molecular and supramolecular factors. The longevity of glutaraldehyde-treated tissue valves can be further improved by special methods. Calcification is especially characteristic for flexing and otherwise moving and pulsating surfaces, typical of many experimental circulatory assist devices and artificial hearts intended for long-term uses.

Aldehydes↗
PubMed1988

Retardation of calcification of bovine pericardium used in bioprosthetic heart valves by phosphocitrate and a synthetic analogue.

The purpose of this study was to determine if phosphocitrate (PC), a naturally occurring inhibitor of calcification, and its synthetic analogue, N-sulpho-2-amino tricarballylate (SAT), administered either by daily injection or local delivery via Alzet osmotic minipump, could inhibit calcification of glutaraldehyde-preserved bovine pericardium used in bioprosthetic heart valves, subcutaneously implanted in rats. Local drug delivery, but not systemic administration, was effective. PC, administered by Alzet minipump (12 mg.kg-1.day-1), inhibited calcification significantly (tissue calcium = 5 +/- 2 micrograms/mg dry tissue, mean +/- SEM), compared with untreated or saline-treated controls (89 +/- 9 and 49 +/- 9 micrograms/mg, respectively). SAT, administered by the same route at both the same and a higher molar dosage, was less potent (tissue calcium = 26 +/- 9 micrograms/mg and 17 +/- 5 micrograms/mg, respectively). PC and SAT therapy were not associated with adverse effects. We conclude that locally administered PC and SAT can inhibit intrinsic calcification of bovine pericardium, with PC being more potent.

Animals↗
PubMed1991

Development of a new in vitro model for studying implantable polyurethane calcification.

The objective of this study was to reproduce mineralization of polymeric substrate in an extracirculatory environment which would facilitate investigation of the calcification mechanism in implantable biomaterials and methods of prevention. Calcification was examined on polyurethane films incubated in metastable solutions of calcium phosphate and the role of strain, serum and polymer porosity was examined. Validation of the model was evaluated by examining the calcification of both highly calcifiable biomaterial (bioprosthetic tissue) and a non-calcifiable biomaterial (charge-modified tissue and polyurethane containing anticalcification agent). It is concluded that the developed model is adequately sensitive to diagnose biomaterials' propensity to calcify and could serve as a pre-screening method to examine calcification mechanism and methods of prevention.

Biocompatible Materials↗
PubMed1991

Biochemical and physico-chemical aspects of biomaterials calcification.

Intrinsic tissue calcification mainly results from increased penetration of plasma proteins into the leaflets of bioprosthetic cardiac valves. The loss of activity of natural calcification inhibitors changes tissue properties and promotes pathological processes. N-vinylpyrrolidone, 3-amino-1,1-hydroxypropylendiphosphonic acid, O,O-diethylvinylphosphonates and antiaggregant (acryloilsalicylic acid) were used to decrease porosity and prevent calcification. gamma-radiation and glutaraldehyde were used to immobilize these agents. Tissue calcification was studied using subcutaneous implantation of the samples in young rats. The study indicates that the copolymerization of N-vinylpyrrolidone, O,O-diethylvinylphosphonates and acryloilsalicylic acid decreases calcium and phosphorous accumulation during in vivo experiments.

Animals↗
PubMed1995

Calcification and fatigue failure in a polyurethane heart value.

The prosthetic heart valves were fabricated from a polyurethane containing a 4,4'-diphenylmethane diisocyanate hard segment, chain-extended with butanediol and with a polyether soft segment. The rate of calcification of these polyurethane heart valves was much slower in a dynamic in vitro test system than similar bioprosthetic heart valves. The calcified deposits were located exclusively at regions of material failure. Fourier transform infrared (FTIR) spectroscopy indicated the involvement of the polyether soft segments of the polymer directly in the calcification process. Calcification of polymer fractions also suggested that small molecular weight extractable components are accelerating factors in the calcification process.

Animals↗
PubMedDate not supplied

Relation between low serum cholesteryl-ester transfer activity and abdominal aortic calcification in normolipidemic elderly subjects.

We studied the relation between cholesteryl-ester transfer activity (CETA) and abdominal aortic calcification in elderly subjects. Compared with 10 young healthy subjects (mean +/- S.D. age, 27 +/-2 years) and to 26 elderly subjects without abdominal aortic calcification (79 +/- 7 years), 16 elderly patients with abdominal aortic calcification (82 +/- 6 years) had significantly lower levels of serum CETA. However, there were no differences in the levels of serum lipids and apolipoproteins, including total cholesterol, triglycerides, high density lipoprotein cholesterol, low density lipoprotein cholesterol and apolipoproteins A-I, A-II, B, C-II and E, between the two elderly groups. When the two groups of elderly subjects were considered together, the level of serum CETA did not correlate significantly with any lipids and apolipoproteins. These results provide evidence that CETA may prevent the development of aortic calcification in normolipidemic elderly people.

Journal Article↗
PubMed1994

Extensive subcutaneous calcification of the forearm in systemic lupus erythematosus.

We report two cases with long-standing systemic lupus erythematosus (SLE) who developed widespread calcification in subcutaneous tissue and peri-articular structures. To our knowledge only 26 case reports have appeared concerning this abnormality in SLE. However, there has been no report of calcification in an SLE patient in the literature of orthopaedic surgery. The calcifications of the forearm were marginally removed because of pain surrounding them. X-ray analysis revealed that the calcification was made of pure calcium phosphate.

Adult↗
PubMed1988

Electrically-induced collagen calcification in pig skin. A histopathologic and histochemical study.

Deposition of calcium salts on collagen fibres in skin of fully anaesthetized pigs was induced by exposure to direct current (d.c.). In biopsies obtained from cathode areas successively from day 1 to day 7 after exposure the histopathologic and histochemical changes before and after the initial deposition of calcium salts have been examined. For comparison skin sites with intradermal injected calcium hydroxyapatite crystals were studied in addition. Small areas of calcified collagen and elastic fibres were noted in viable tissue 2 days after d.c. exposure. In succeeding days the calcified areas enlarged with new deposits always more superficial and closer to the epidermis than the original calcium deposits. Preconditions for calcification appear to be (1) a pH change in basic direction and/or the electrochemical processes specific to the cathode area and (2) a viable tissue. Elastic fibres appear to have a lower calcification threshold than collagen fibres. A positive staining for glycoproteins (PAS) and glycosaminoglycans (alcian blue pH 2.5) was noted in the calcified collagen fibres simultaneously with the calcification. In succeeding days the intensity of the staining reactions increased. Whether changes in the glycoproteins, collagen and its intimately bound glycosaminoglycans precede the calcification or the staining reactions develop secondarily to this deposition is not known. However, seven days after intradermal injections of Ca-apatite crystals in pig skin small and large crystals were observed ultrastructurally without any relation to collagen fibrils, but the calcified tissue presented a positive PAS and alcian blue reaction from day 2. Thus the PAS and alcian blue stainings in this model develop secondary to the deposition of calcium salts.

Animals↗
PubMed1991

Cardiac calcifications: difficult MRI diagnosis.

Magnetic resonance imaging (MRI) and computed tomography (CT) were performed in 40 patients with a variety of cardiovascular diseases. These imaging modalities were compared to investigate their relative value in the assessment of cardiovascular diseases. Of these 40 patients, 7 were found by CT to have detectable cardiovascular calcifications. These patients included one calcified mitral stenosis, one calcified coronary artery, one calcified type B aortic dissection, two calcified myocardial infarctions, and two patients with calcific pericarditis. In several cases, MRI was misleading because of difficulty in detecting calcifications. We present a series of cases illustrating a limitation of MRI in identifying diagnostically and clinically important cardiovascular calcifications.

Adolescent↗
PubMed1994

Prognostic significance of cardiac cinefluoroscopy for coronary calcific deposits in asymptomatic high risk subjects.

OBJECTIVES: This research investigated the prognostic significance of radiographically detectable coronary calcific deposits. BACKGROUND: Coronary calcific deposits are almost always associated with coronary atherosclerosis. We investigated the association between fluoroscopically determined coronary calcium and coronary heart disease end points at 1 year of follow-up. METHODS: This prospective population-based cohort study was conducted in the suburbs of Los Angeles. Fourteen hundred sixty-one asymptomatic adults with an estimated > or = 10% risk of having a coronary heart disease event within 8 years underwent cardiac cinefluoroscopy for assessment of coronary calcium at initiation of the study. Clinical status including angina, documented myocardial infarction, myocardial revascularization and death from coronary heart disease were determined after 1 year. RESULTS: The prevalence of calcific deposits was high (47%). A follow-up examination at 1 year was successfully completed in 99.9% of subjects. Six subjects (0.4%) had died from coronary heart disease and 9 (0.6%) had had a nonfatal myocardial infarction. Thirty-seven subjects (2.5%) reported angina pectoris, and 13 (0.9%) had undergone myocardial revascularization. Fifty-three subjects had at least one event during the 1-year period. Radiographically detectable calcium was associated with the presence of at least one of these end points, with a risk ratio of 2.7 (confidence limits 1.4, 4.6). The presence of coronary calcium was an independent predictor of at least one end point when controlling for age, gender and risk factors. However, three deaths due to coronary heart disease and two nonfatal myocardial infarctions occurred in subjects without detectable coronary calcium. CONCLUSIONS: The presence of coronary calcific deposits incurs an increased risk of coronary heart disease events in asymptomatic high risk subjects at 1 year. This increased risk is independent of that incurred by standard risk factors.

Aged↗
PubMed1995

Early onset bilateral calcifications and epilepsy.

Bilateral occipital calcifications associated with epilepsy and sometimes with celiac disease have been described previously. A boy with bilateral frontal and occipital diffuse calcifications accompanied by failure to thrive, nephrogenic diabetes insipidus, developmental delay and seizures, but without celiac disease is presented. Follow-up at 3 years of age disclosed neurodevelopmental delay, height and weight less than expected for age, and seizures controlled with carbamazepine. The uncommon association of these features and the early onset of symptoms is discussed. Although bilateral occipital calcifications share some clinical features with bilateral fronto-occipital calcifications, it is arguable whether the two are on a spectrum of a single disease or represent separate entities.

Brain Diseases↗