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PubMed2006

Shwachman-Diamond syndrome: an inherited model of aplastic anaemia with accelerated angiogenesis.

Bone marrow angiogenesis is increased in myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML), but has not been studied in inherited or acquired marrow failure syndromes. Shwachman-Diamond syndrome (SDS) carries a high risk of MDS/AML and is characterised by marrow stromal dysfunction. Compared with controls, SDS patients without MDS/AML had higher marrow microvessel density. Stromal VEGF gene expression, stromal vascular endothelial growth factor (VEGF) secretion and VEGF levels in serum and marrow mononuclear cells were normal. Future studies should investigate the mechanism for increased angiogenesis in SDS, and whether SDS marrow, with its increased angiogenesis, promotes progression of malignant clones.

Abnormalities, Multiple↗
PubMed1992

Intravenous gamma-globulin therapy in Diamond-Blackfan anemia.

Pure red cell aplasia (PRCA) is a rare disorder of erythrocyte production which is believed to have an autoimmune basis in most cases. Diamond-Blackfan anemia (DBA) is one type of congenital PRCA. Since PRCA has been reported to respond to intravenous gamma-globulin (IVGG) therapy, we administered IVGG to a 2 year old girl with DBA resistant to corticosteroids and observed slight therapeutic effect.

Adrenal Cortex Hormones↗
PubMed1997

Transient erythrophagocytosis in Diamond-Blackfan anemia.

We report on a 4-month-old Japanese infant girl with Diamond-Blackfan anemia (DBA) as shown by congenital macrocytic pure red cell hypoplasia with marked reduction of erythroid precursors in bone marrow, reticulocytopenia, increased fetal hemoglobin, and elevated adenosine deaminase activity in peripheral blood. She responded poorly to conventional doses of corticosteroids, however, with high-dose corticosteroids she responded with reticulocytosis and an elevation of hemoglobin level above 12 g/dL. Erythrophagocytosis was noted during the tapering period of prednisone when her hemoglobin level declined to 7.6 g/dL and reticulocyte level to 0.4%. At that time, the erythrophagocytosis was noted in about 60% of marrow histiocytes. These findings were not observed prior to or during the high dose prednisone therapy. We speculate that one of the causes of pure red cell aplasia and reticulocytopenia in DBA is mediated by erythrophagocytosis.

Bone Marrow↗
PubMed1978

Dermabrasion by diamond fraises revolving at 85,000 revolutions per minute.

Use of a high-speed, air-driven turbo-grinder equipped with diamond fraises that revolve at 85,000 revolutions per minute has improved results in dermabrasions on the face by, it is estimated, 50%. Dermabrasions have been done with this turbo-grinder for scarring from acne, actinic damage, syringomata, lesions of adenoma sebaceum and some other facial conditions. The rapid evaporation, nonimflammability, nonnarcotic, and excellent freezing properties of Freon 12 eliminate the necessity for auxiliary cooling fans. It is thought too that the incidence of secondary infections and keloids have been decreased by use of an ointment of erythromycin (1%) topically during the healing period.

Acne Vulgaris↗
PubMed1987

Success of bone marrow transplantation in congenital Diamond-Blackfan anaemia: a case report.

A 6-yr-old girl with congenital corticosteroid-resistant pure red cell aplasia was treated with bone marrow transplant from her HLA-identical, MLC-unreactive sister in November 1984 following conditioning with busulfan and cyclophosphamide. Full engraftment was obtained and the patient at 21 months post-transplant is in excellent clinical condition maintaining normal red cell counts. We conclude that BMT should be considered as a therapy for at least the most severe cases of Diamond-Blackfan anaemia resistant to corticosteroids. Successful outcome of this therapy provides an argument for the stem cell origin of this disorder.

Bone Marrow Transplantation↗
PubMed1988

Cyclosporine in steroid-resistant Diamond-Blackfan anaemia.

Two siblings with Diamond-Blackfan anaemia (DBA) and several congenital malformations were first treated with corticosteroids and blood transfusions. High steroid doses were needed, but in spite of this haemoglobin values periodically fell below acceptable levels. Cyclosporine was then given in addition to prednisolone. A slow increase in haemoglobin levels was observed over 2-3 months, and the prednisolone doses could be reduced gradually. Two short communications in the literature report similar experiences. Cyclosporine could be tried in DBA when reasonable corticosteroid doses do not give a satisfactory response. Since the main effect of cyclosporine is a specific inhibition of T-lymphocytes, the observed therapeutic effect in DBA indicates that T-lymphocytes may play an important role in the pathogenesis of this disease.

Anemia, Aplastic↗
PubMed1975

The ultrastructure of Trichomonas vaginalis donné before and after transfer from vaginal secretion to Diamonds medium.

Cell of Trichomonas vaginalis (T. vag.) obtained from five patients with severe trichomoniasis were fixed for electron microscopy directly in the vaginal fluid. Samples of the same material from three of the patients was inoculated into Diamonds medium and propagated for 3-6 weeks. During the first 3-4 weeks in vitro the fine structure of all cells was changed. The shape of the nucleus, the size of the Golgi apparatus and adjacent vesicles, the fine structure of the chromatic granules, and the mastigont were all changed when compared to the organelles of the originally isolated cells. In addition the "ectoplasm" had disappeared, the glycogen granules had become sparse, and the number of free cytoplasmic ribosomes had increased. On the other hand, the large food vacuoles and the cell membranes generally were unchanged. Mycoplasms were observed in the original isolate and were also seen after more than 6 weeks of propagation, both as free organisms in the culture medium and within the large food vacuoles of "in vitro" cultured cells.

Cell Nucleus↗
PubMed2002

Isolation and structure of higher diamondoids, nanometer-sized diamond molecules.

We exploited the exceptional thermal stability and diverse molecular shapes of higher diamondoids (C22 and higher polymantanes) to isolate them from petroleum. Molecules containing 4 to 11 diamond-crystal cages were isolated and crystallized, and we obtained single-crystal x-ray structures for representatives from three families. Rigidity, strength, remarkable assortments of three- dimensional shapes, including resolvable chiral forms, and multiple, readily derivatizable attachment sites make them valuable nanometer-size molecular building blocks.

Journal Article↗
PubMed2005

The ultrasmoothness of diamond-like carbon surfaces.

The ultrasmoothness of diamond-like carbon coatings is explained by an atomistic/continuum multiscale model. At the atomic scale, carbon ion impacts induce downhill currents in the top layer of a growing film. At the continuum scale, these currents cause a rapid smoothing of initially rough substrates by erosion of hills into neighboring hollows. The predicted surface evolution is in excellent agreement with atomic force microscopy measurements. This mechanism is general, as shown by similar simulations for amorphous silicon. It explains the recently reported smoothing of multilayers and amorphous transition metal oxide films and underlines the general importance of impact-induced downhill currents for ion deposition, polishing, and nanopattering.

Journal Article↗
PubMed2006

Electrostatic self-assembly of binary nanoparticle crystals with a diamond-like lattice.

Self-assembly of charged, equally sized metal nanoparticles of two types (gold and silver) leads to the formation of large, sphalerite (diamond-like) crystals, in which each nanoparticle has four oppositely charged neighbors. Formation of these non-close-packed structures is a consequence of electrostatic effects specific to the nanoscale, where the thickness of the screening layer is commensurate with the dimensions of the assembling objects. Because of electrostatic stabilization of larger crystallizing particles by smaller ones, better-quality crystals can be obtained from more polydisperse nanoparticle solutions.

Journal Article↗
PubMed2006

Coherent dynamics of coupled electron and nuclear spin qubits in diamond.

Understanding and controlling the complex environment of solid-state quantum bits is a central challenge in spintronics and quantum information science. Coherent manipulation of an individual electron spin associated with a nitrogen-vacancy center in diamond was used to gain insight into its local environment. We show that this environment is effectively separated into a set of individual proximal 13C nuclear spins, which are coupled coherently to the electron spin, and the remainder of the 13C nuclear spins, which cause the loss of coherence. The proximal nuclear spins can be addressed and coupled individually because of quantum back-action from the electron, which modifies their energy levels and magnetic moments, effectively distinguishing them from the rest of the nuclei. These results open the door to coherent manipulation of individual isolated nuclear spins in a solid-state environment even at room temperature.

Journal Article↗
PubMed2006

Loss of the mouse ortholog of the shwachman-diamond syndrome gene (Sbds) results in early embryonic lethality.

Mutations in SBDS are responsible for Shwachman-Diamond syndrome (SDS), a disorder with clinical features of exocrine pancreatic insufficiency, bone marrow failure, and skeletal abnormalities. SBDS is a highly conserved protein whose function remains largely unknown. We identified and investigated the expression pattern of the murine ortholog. Variation in levels was observed, but Sbds was found to be expressed in all embryonic stages and most adult tissues. Higher expression levels were associated with rapid proliferation. A targeted disruption of Sbds was generated in order to understand the consequences of its loss in an in vivo model. Consistent with recessive disease inheritance for SDS, Sbds(+/-) mice have normal phenotypes, indistinguishable from those of their wild-type littermates. However, the development of Sbds(-/-) embryos arrests prior to embryonic day 6.5, with muted epiblast formation leading to early lethality. This finding is consistent with the absence of patients who are homozygous for early truncating mutations. Sbds is an essential gene for early mammalian development, with an expression pattern consistent with a critical role in cell proliferation.

Animals↗
PubMed2006

Shwachman-Diamond syndrome: UK perspective.

So much has been added to our knowledge of Shwachman-Diamond syndrome (SDS) since it was last reviewed in this journal some 25 years ago, that there is now an urgent need to bring the condition to the attention of a new generation of paediatricians. SDS, although a rare autosomal recessive disorder, demands wide attention because it features in the differential diagnosis of a number of important childhood diseases. It can be diagnosed in children of all ages, or in adults. SDS most commonly presents in infancy with features of exocrine pancreatic insufficiency, bone marrow dysfunction, and short stature.

Bone Marrow Diseases↗
PubMed1997

Diamond-Blackfan anaemia in a girl with a de novo balanced reciprocal X;19 translocation.

A 7 year old girl is described with congenital hypoplastic anaemia (Diamond-Blackfan anaemia, DBA) and an apparently balanced reciprocal translocation, 46,XX,t(X;19)(p21;q13). The girl has associated features including short stature, unilateral kidney hypoplasia, and a branchial cyst. Fluorescent in situ hybridisation (FISH) studies with 19q specific cosmids showed that the chromosome 19 breakpoint is located between the RYR1 and the XRCC11 loci spanning a physical region of 5 Mb. There is no family history of DBA and the parents and two healthy sibs have normal karyotypes. This is the first report of a balanced translocation associated with DBA and we suggest that the distinct phenotype has resulted from a de novo disruption of a functional gene. DBA can be inherited as an autosomal trait and our observation may indicate a candidate gene for the disorder in the 19q13 region.

Blood Transfusion↗
PubMed2000

A microdeletion in 19q13.2 associated with mental retardation, skeletal malformations, and Diamond-Blackfan anaemia suggests a novel contiguous gene syndrome.

Diamond-Blackfan anaemia (DBA) is a constitutional red blood cell hypoplasia which may be associated with a variety of developmental abnormalities. A gene for DBA was recently mapped to chromosome 19q13.2 and subsequently cloned. Analysis of 19q marker alleles in DNA of sporadic DBA cases showed de novo microdeletions in three patients also presenting with mental retardation. We have studied one of these patients and characterised the deletion by fluorescence in situ hybridisation (FISH) to extended DNA fibres. The deletion was shown to be continuous over a 3.2 Mb region and the fibre-FISH analysis showed both chromosomal breakpoints. In combination, the clinical and molecular findings suggest a contiguous gene syndrome with a gene locus for mental retardation and, probably, skeletal malformations included in the deletion.

Bone and Bones↗
PubMed1982

Systemic arterial hemodynamics in the diamond python Morelia spilotes.

Studies of pulsatile systemic arterial hemodynamics were conducted in 10 diamond python snakes to test the hypothesis that body shape--through spatial dispersion of peripheral reflecting sites--is an important determinant of impedance patterns and of pulse wave contour. Findings support the hypothesis. Flow patterns in the aortic roots were similar to those in humans, sheep, dogs, rabbits, and guinea pigs, but in contrast to larger animals, little change in flow contour was seen in other arteries. Pressure wave contour was similar in all systemic arteries from which records were taken with no secondary diastolic wave under any circumstances. Impedance patterns at different sites showed none of the fluctuations that in other animals are attributable to discrete wave reflection. Discrete proximal wave reflection at the confluence of aortic arches was minimal. Data are explicable on the basis of widely distributed peripheral reflecting sites--a consequence of the snake's long and tapered body.

Animals↗
PubMed1983

Pulse-wave propagation in the arterial system of the diamond python Morelia spilotes.

Pulse-wave velocity (PWV) and pulse-wave amplification (PWA) were measured over a proximal [51 +/- 3 (SE) cm] and distal segment (60 +/- 6 cm) of the common descending aorta of 10 anesthetized diamond python snakes (Morelia spilotes). For proximal and distal segments, PWV values were 551 +/- 66 and 921 +/- 116 cm/s and PWA were 0.91 +/- 0.05 and 0.91 +/- 0.06, respectively. PWV for proximal and distal segments were significantly different (P less than 0.02), but PWA were not. PWA for separate harmonics of heart frequency showed no significant increase above unity. Increase of PWV between distal and proximal aorta indicates a reduction in arterial distensibility, a phenomenon that in other species is associated with amplification of the pressure pulse; this was not observed in snakes. Using a simple elastic tube model 56 cm in length and 3 mm in diameter it was found that the amplification produced by the measured PWV changes is offset by attenuation due to viscous damping. Thus similarity of pulse-wave contour throughout the snake's aorta is attributable to the opposing effects of elastic nonuniformity and viscous damping.

Animals↗
PubMed2006

[Hypertransaminasemia as a manifestation of Shwachman-Diamond syndrome].

Shwachman-Diamond syndrome (SDS) is the second most common cause of congenital exocrine pancreatic insufficiency after cystic fibrosis. SDS is an autosomal recessive multisystemic disorder, with wide heterogenicity in its clinical characteristics. The central features of this syndrome are pancreatic exocrine and bone marrow dysfunction (mainly neutropenia). Other features are skeletal abnormalities, hepatomegaly, elevation of serum aminotransferase levels, short stature and frequent infections. We present two patients who were referred to us because of persistent hypertransaminasemia. In both patients, liver function returned to normal and pancreatic function improved. Both patients showed several neutropenic episodes but no bone disorders, which does not exclude the diagnosis.

Bone Marrow Diseases↗