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At least 469 records · Page 26Linked to original sources
PubMed1983

[Effect of the action of rotary diamond instruments on the enamel and dentine. Scanning electron microscopic study].

Mesio-occluso-distal cavities were prepared "in vitro" on human teeth using cylindrical diamond instruments of fine granulometry and operating at high and very high speeds. The surface states obtained on enamel and dentine were examined with scanning electron microscopy. The striae produced by these instruments appeared as well marked straight ridges and depressions the depths of which were higher than those produced by steel and tungsten carbide burs. Along cavo-surface angles, superficial prism fractures and/or border irregularities were visible, especially in relation to the cutting plane orientation versus the prism axes. A highly adhering smear layer on enamel walls was observed. The rotational direction of the diamond instruments did not appear to affect the quality of the cavo-surface box angles as it did for steel and tungsten carbide burs.

Adult↗
PubMed1984

Diamond knife corneal incisions.

In the following study, eight linear corneal incisions were made in two human cadaver eyes with three diamond-bladed knives: the KOI, Cooper, and Micra micrometer knives. Prior to the incisions, ultrasonic pachymetry readings of the corneas were recorded, and all knives were calibrated to a guarded cutting depth of 0.55 mm (550 microns). Following the incisions, the corneas were fixed, sectioned, and incision depth carefully measured histologically. In all but two incisions made with the Cooper knife, the incision depth was significantly or highly significantly greater than the calibrated diamond length. There was a significant or highly significant difference in depth among incisions made with the same knife, as well as among incisions made with different knives. Depth variability was noted for all knives except for two comparisons between incisions made with a Micra and KOI knife, and one comparison between two incisions, both made with the Cooper knife. Difference in knife design which may account for the variation of incision depth and contribute to the unpredictability of radial keratotomy is discussed.

Cadaver↗
PubMed1984

Use of diamond knives in ocular surgery.

Scanning electron microscopy is used to evaluate and compare the morphology of corneal incisions made with ophthalmic razor knives and with a diamond knife designed for eye surgery. Razor blade incisions cause more disruption and trauma to the epithelial surface, and the underlying stroma shows some signs of stress. The diamond knife cuts more smoothly leaving the epithelial surface relatively intact and the underlying stroma cleanly separated.

Animals↗
PubMed1981

Platelet number and function in Diamond-Blackfan anemia.

Congenital red cell aplasia (Diamond-Blackfan anemia) is occasionally associated with hematologic defects other than a deficiency of red blood cell progenitors, but such alterations have not been well studied. The frequency and magnitude of abnormalities in platelet count and platelet function were therefore examined in 38 patients. Thrombocytosis was seen in 21 patients, and 12 had mild thrombocytopenia on at least one occasion. Elevated platelet counts were demonstrated repeatedly in nine children. The three patients with the lowest platelet counts also had leukopenia. Platelet aggregation was normal in all 16 patients in whom it was studied, and bleeding times were within the normal range in 14 of them. Bleeding signs and symptoms were not observed. It is concluded that thrombocytosis or thrombocytopenia often occurs but that platelet function is normal in patients with Diamond-Blackfan anemia.

Adolescent↗
PubMed1994

Malignant fibrous histiocytoma in a patient with Blackfan-Diamond anemia.

Blackfan-Diamond anemia, a chronic, pure red cell aplasia, is rare. Malignant fibrous histiocytoma is also uncommon; it can arise in pre-existing bone lesions. The authors describe a 23-year-old man with Blackfan-Diamond anemia complicated by hemochromatosis in whom malignant fibrous histiocytoma developed in the distal femur.

Adult↗
PubMed1993

Correlation of in vitro enhancement of erythropoiesis and clinical response to steroids in Diamond-Blackfan anaemia.

To investigate whether the clinical response to steroids in Diamond-Blackfan anaemia (DBA) can be predicted in vitro, erythroid cultures from six patients was performed. The increment of burst forming unit erythroid (BFU-E) and colony forming unit erythroid (CFU-E) derived colonies had been studied with the in vitro addition of steroids. Our results showed: 1) a relative insensitivity to low and optimum concentration of erythropoietin (Epo) in cultures, and 2) lower CFU-E and BFU-E colony formation in all cases studied. (CFU-Es of normal controls/10(5) cells; were 85.6, BFU-Es 37.8, while the patients' CFU-E were 18.1 and BFU-E 7/10(5) cells with two IU of Epo) with poor or no growth in three cases, 3) increment up to 60-110% with in vitro addition of steroids in three cases, 4) high serum Epo levels in all Diamond-Blackfan anaemia patients, and 5) clinical response to steroids in the three patients who responded in vitro.

Adult↗
PubMed1995

Identification of coronary artery disease by 99mTc-MIBI myocardial perfusion single photon emission computed tomography: evaluation using Diamond's method and segmental score system.

Three hundred and eighty-one consecutive patients referred to our Nuclear Medicine Service from the Cardiology Department during a period of two years have been studied to evaluate Coronary Artery Disease (CAP) using 99mTc-MIBI single photon emission computed tomography (SPECT). The sensitivity and specificity for detecting CAD in the whole group of patients, referred (n = 161) or not (n = 220) for coronary angiography, were calculated following Diamond's method, and were found to be 87% and 92%, respectively. Diamond's method estimates these values from those obtained in the subset of patients with angiography referral (sensitivity 91% and specificity 85%) and the pattern of SPECT responses of both groups (69% and 52%, respectively). A new segmental score system was used to evaluate the location and extent of CAD in the catheterized group. The sensitivity for detecting individual artery disease was 69% and specificity was 81%. The sensitivity in patients with single, double and triple-vessel disease was 90%, 96% and 89%, respectively. In the subgroup of patients without infarction (n = 66) the sensitivity and specificity were 76% (19/25) and 90% (37/41).

Coronary Angiography↗
PubMed1997

[Umbilical cord blood transplantation for a patient with Diamond-Blackfan syndrome].

A five-year-old girl with Diamond-Blackfan syndrome received cord blood transplantation from an HLA-identical sibling. The patient showed pale face at birth, and was diagnosed to have Diamond-Blackfan syndrome. She had been treated with prednisolone (PSL), high dose of methylprednisolone, erythropoietin, and anti-lymphocyte globulin. Despite of these intensive therapies, erythropoiesis did not entirely improve, and transfusion of red blood cells had been required every third or fourth week until cord blood transplantation. Conditioning regimen consisted of thoraco-abdominal irradiation (TAI; 8 Gy), cyclophosphamide (CY; 50 mg/kg x 4), and anti-thymocyte globulin (ATG; 2.5 mg/kg x 4), Cyclosporin (CyA 3 mg/kg) was administered for the prophylaxis of graft-versus-host disease (GVHD). 4.14 x 10 (7)/kg of cord blood mononuclear cells were infused to the patient. White blood cell (WBC) and reticulocyte counts increased promptly, but recovery of platelet count was delayed. Skin GVHD (grade I) appeared on day +9, which responded to the administration of PSL (2 mg/kg). Chromosomal analyses of bone marrow cells for sex mismatch revealed complete chimerism on day +14, on day +28 and thereafter. Umbilical cord blood cells can be an alternative source of hematopoietic stem cells for allogeneic transplantation.

Child, Preschool↗
PubMed1997

Expression of SCL is normal in transfusion-dependent Diamond-Blackfan anemia but other bHLH proteins are deficient.

Basic helix-loop-helix proteins, which are tissue specific (SCL) or broadly expressed (E proteins), interact positively to regulate erythroid specific genes. Here, expression of SCL and two broadly expressed E proteins, E47 and HEB, was high early in erythroid differentiation and declined during maturation. Stimulation of erythroid progenitors/precursors with stem cell factor (SCF) enhanced SCL and E protein levels, one mechanism by which SCF may increase erythroid proliferation. Interactions between SCL and E proteins are competed by Id2, which binds and sequesters E proteins. Upregulation of Id2, demonstrated here late in erythroid differentiation, may downregulate genes involved in erythroid proliferation/differentiation. We examined expression of bHLH proteins in transfusion-dependent patients with Diamond-Blackfan anemia (DBA) to determine if these interactions are disrupted. In erythroblasts from patients, expression of SCL protein and mRNA was normal and SCL increased in response to SCF. However, E47 and HEB protein levels were significantly decreased. Id2 was strongly expressed in patients. Through reduction of SCL/E protein heterodimer formation, abnormal levels of bHLH transcription factors may affect expression of erythroid specific genes, such as beta globin. Stimulation of Diamond-Blackfan cells with SCF partially compensated for this defect, enhancing expression of E47, HEB, and SCL. SCF may function to increase SCL/E protein heterodimer formation, which may be one of the mechanisms through which SCF stimulates erythroid proliferation/differentiation in DBA.

Basic Helix-Loop-Helix Proteins↗
PubMed1998

Duplication of distal thumb phalanx in Shwachman-Diamond syndrome.

Shwachman-Diamond syndrome (SDS) comprises of exocrine pancreatic dysfunction, various degree of pancytopenia, and metaphyseal dysplasia. We report on a child with SDS and duplication of distal thumb phalanx. This combination has not been reported previously. We suggest that supernumerary thumb is likely a rare skeletal manifestation of SDS and that SDS should be considered in the differential diagnosis of patients with bone marrow failure and duplication of the thumb along with Blackfan-Diamond/Aase syndrome and Fanconi's anemia.

Exocrine Pancreatic Insufficiency↗
PubMed1987

Diamond-dusted microspatula tips for vitreoretinal surgery.

We have developed a microsurgical spatula set consisting of four different tips and a universal handle. The set offers a range of tip angulation of 30 degrees, 45 degrees, 60 degrees, and 80 degrees. The bottom surfaces of the spatula tips are covered with fine diamond dust. The 30 degrees tip has a blunt and tapered end. All tips can be introduced through a conventional 20-gauge sclerotomy in a pars plana vitrectomy. The tips fit on a universal handle. The set has been used as a complement to vitreous forceps in dissecting and removing preretinal membrane.

Carbon↗
PubMed2001

In vitro and in vivo investigations into the biocompatibility of diamond-like carbon (DLC) coatings for orthopedic applications.

Diamond-like carbon (DLC) shows great promise as a durable, wear- and corrosion-resistant coating for biomedical implants. The effects of DLC coatings on the musculoskeletal system have not been investigated in detail. In this study, DLC coatings were deposited on polystyrene 24-well tissue culture plates by fast-atom bombardment from a hexane precursor. Two osteoblast-like cell lines were cultured on uncoated and DLC-coated plates for periods of up to 72 h. The effects of DLC coatings on cellular metabolism were investigated by measuring the production of three osteoblast-specific marker proteins: alkaline phosphatase, osteocalcin, and type I collagen. There was no evidence that the presence of the DLC coating had any adverse effect on any of the parameters measured in this study. In a second series of experiments, DLC-coated cobalt-chromium cylinders were implanted in intramuscular locations in rats and in transcortical sites in sheep. Histologic analysis of specimens retrieved 90 days after surgery showed that the DLC-coated specimens were well tolerated in both sites. These data indicate that DLC coatings are biocompatible in vitro and in vivo, and further investigations into their long-term biological and tribological performance are now warranted.

Alkaline Phosphatase↗
PubMed2005

Successful treatment of Diamond-Blackfan anemia with metoclopramide.

Diamond-Blackfan anemia (DBA) is a congenital anemia characterized by a low reticulocyte count, the absence or severe reduction of hemoglobin-containing cells in the bone marrow, and normal megakaryocytic and granulocytic differentiation. Although the anemia may initially respond to corticosteroid therapy, many patients require lifelong red blood cell (RBC) transfusion, leading to infectious complications and iron overload. Metoclopramide has recently been used to treat DBA. Treatment with metoclopramide induces the release of prolactin from the pituitary and stimulates erythropoiesis. For these reasons, we used metoclopramide to treat a 20-year-old man with DBA refractory to low and high doses of corticosteroids, cyclosporin A, and tacrolimus (FK506). The hemoglobin and hematocrit slowly increased, and he has remained asymptomatic and transfusion-independent for 8 months. Metoclopramide therapy should be considered in patients with refractory DBA before treatment-related complications develop.

Adult↗
PubMed2005

Chronic parvovirus infection and G6PD deficiency masquerading as Diamond-Blackfan anemia.

Bone marrow aplasia due to parvovirus B19 infections is usually mild and self-limited. In patients with hereditary or acquired hemolytic anemias, B19 infection can cause a severe and life-threatening anemia due to the shortened half-life of red cells, but here, too, the transient nature of the infection soon remits the symptoms. Chronic infections with parvovirus are more characteristically associated with immunodeficiency states. We report here a case of B19-induced anemia in a patient with G6PD deficiency and hypogammaglobulinemia which was mislabeled as Diamond-Blackfan anemia until the use of modern laboratory techniques allowed a correct diagnosis to be made.

Adult↗
PubMed2006

Diamond-Blackfan anemia associated with beta-thalassemia trait.

A 14-month-old boy was referred to our hospital for evaluation of severe anemia. In the bone marrow aspiration smear, normal cellularity with severe erythroblastopenia (3%) was observed. The hemoglobin electrophoresis of the patient and his father were compatible with the beta-thalassemia trait. Because macrocytosis of Diamond-Blackfan anemia (DBA) is masked by microcytosis of beta-thalassemia trait, the diagnosis of DBA co-existing with beta-thalassemia trait might be challenging. We report herein a case of DBA co-existing with beta-thalassemia trait in a Turkish boy.

Adolescent↗
PubMed2004

Nonsense-mediated and nonstop decay of ribosomal protein S19 mRNA in Diamond-Blackfan anemia.

Mutations in the ribosomal protein (RP)S19 gene have been found in about 25% of the cases of Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia that includes variable physical malformations. Various mutations have been identified in the RPS19 gene, but no investigations regarding the effect of these alterations on RPS19 mRNA levels have been performed. It is well established that mutated mRNA containing a premature stop codon (PTC) or lacking a stop codon can be rapidly degraded by specific mechanisms called nonsense mediated decay (NMD) and nonstop decay. To study the involvement of such mechanisms in DBA, we analyzed immortalized lymphoblastoid cells and primary fibroblasts from patients presenting different kinds of mutations in the RPS19 gene, generating allelic deletion, missense, nonsense, and nonstop messengers. We found that RPS19 mRNA levels are decreased in the cells with allelic deletion and, to a variable extent, also in all the cell lines with PTC or nonstop mutations. Further analysis showed that translation inhibition causes a stabilization of the mutated RPS19 mRNA. Our findings indicate that NMD and nonstop decay affect the expression of mutated RPS19 genes; this may help to clarify genotype-phenotype correlations in DBA.

Alleles↗
PubMed2004

Hemocompatibility of nitrogen-doped, hydrogen-free diamond-like carbon prepared by nitrogen plasma immersion ion implantation-deposition.

Amorphous hydrogenated carbon (a-C:H) has been shown to be a potential material in biomedical devices such as artificial heart valves, bone implants, and so on because of its chemical inertness, low coefficient of friction, high wear resistance, and good biocompatibility. However, the biomedical characteristics such as blood compatibility of doped hydrogen-free diamond-like carbon (DLC) have not been investigated in details. We recently began to investigate the potential use of nitrogen-doped, hydrogen-free DLC in artificial heart valves. In our experiments, a series of hydrogen-free DLC films doped with nitrogen were synthesized by plasma immersion ion implantation-deposition (PIII-D) utilizing a pulsed vacuum arc plasma source and different N to Ar (FN/FAr) gas mixtures in the plasma chamber. The structures and properties of the film were evaluated by Raman spectroscopy, Rutherford backscattering spectrometry (RBS), and X-ray photoelectron spectroscopy (XPS). To assess the blood compatibility of the films and the impact on the blood compatibility by the presence of nitrogen, platelet adhesion tests were conducted. Our results indicate that the blood compatibility of both hydrogen-free carbon films (a-C) and amorphous carbon nitride films are better than that of low-temperature isotropic pyrolytic carbon (LTIC). The experimental results are consistent with the relative theory of interfacial energy and surface tension including both dispersion and polar components. Our results also indicate that an optimal fraction of sp2 bonding is desirable, but an excessively high nitrogen concentration degrades the properties to an extent that the biocompatibility can be worse than that of LTIC.

Albumins↗
PubMed2006

Fluorinated diamond-like carbon as antithrombogenic coating for blood-contacting devices.

Diamond-like carbon (DLC) is being considered for widespread clinical use as a surface coating for cardiovascular devices. We synthesized fluorinated DLC (F-DLC) coatings in order to create a more hydrophobic surface with improved antithrombogenicity and flexibility when compared with conventional DLC coatings by combining the inertness of DLC films with the advantage of fluorination. The purpose of this study was to evaluate the in vitro hemocompatibility and in vivo biocompatibility of the F-DLC coating for medical devices. The in vitro whole blood model confirmed that platelet loss was lower in the F-DLC group than in the noncoated group (SUS316L), which suggests the adhesion of a smaller number of platelets to F-DLC-coated materials. Furthermore, the biomarkers of mechanically induced platelet activation (beta-thromboglobulin) and activated coagulation (thrombin-antithrombin-three complex) were markedly reduced in the F-DLC-coated group. In vivo rat implant model studies revealed no excessive local and systemic inflammatory responses in the F-DLC group. The thickness of the fibrous tissue capsule surrounding the F-DLC-coated disk was almost equal to that of the noncoated SUS316L disk, which has the favorable biocompatibility for metallic implant materials. F-DLC coating thus appears to be a promising candidate for use as a coating material in blood-contacting devices.

Animals↗