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PubMed1997

The diamond-coated sonic scaler tip. Part II: Loss of substance and alteration of root surface texture after different scaling modalities.

The authors have developed a set of four modified sonic scaler inserts with variously shaped shafts and diamond-coated budded inserts. The inserts are specially designed for the furcation area since instruments used hitherto have not been successful in completely preventing slow continuous periodontal breakdown in multirooted teeth. To improve understanding of their clinical effectiveness, instrumentation of dentin samples was done with a curette as well as conventional and modified sonic scaler inserts under standardized conditions. The results showed that significantly greater amounts of tooth substance were removed with the diamond-coated airscaler tips than with the conventional tip. The depth of substance removal was comparable to that obtained with hand instruments and increased with application force. Although differences in surface texture were found among the different modes of scaling, it remains to be determined whether they are of clinical significance.

Analysis of Variance↗
PubMed1998

Principles of proximal cavity preparation and finishing with ultrasonic diamond tips.

Conventional treatment of proximal cavities can result in significant damage to the adjacent dentition. This paper describes a recently developed technique of proximal cavity preparation and finishing by use of selectively diamond-coated, ultrasonically driven instruments. By using these instruments for composite, compomer, ceramic, amalgam, and even gold restorations, the inadvertent damage to neighboring teeth is completely avoided. This article demonstrates the effective utilization of the diamond-tipped ultrasonic instruments for the preparation of primary lesions and the replacement of existing restorations.

Dental Caries↗
PubMed1996

Prenatal diagnosis of Blackfan-Diamond syndrome: case report and review of the literature.

A case of prenatally diagnosed autosomal dominant congenital hypoplastic anaemia (Blackfan-Diamond syndrome or Aase congenital anaemia) causing hydrops fetalis is presented. Recommendations for the prenatal management of Blackfan-Diamond syndrome (BDS) include prepregnancy counselling for parents with BDS, detailed and serial fetal ultrasonography and echocardiography, cordocentesis if there are signs of anaemia, consideration of in utero transfusions and planned early delivery if the fetus is affected.

Adult↗
PubMed1997

Dofetilide in patients with left ventricular dysfunction and either heart failure or acute myocardial infarction: rationale, design, and patient characteristics of the DIAMOND studies. Danish Investigations of Arrhythmia and Mortality ON Dofetilide.

BACKGROUND: Attempts to prolong life with antiarrhythmic drugs in patients at increased risk of sudden cardiac death have so far been disappointing or inconclusive. HYPOTHESIS: The Danish Investigations of Arrhythmia and Mortality ON Dofetilide (DIAMOND) encompass two survival studies testing the prophylactic use of the selective potassium-channel blocker, dofetilide, in patients at high risk of sudden death. METHODS: The first study includes patients admitted to hospital with congestive heart failure (CHF), the other includes patients with acute myocardial infarction (MI) within the previous 7 days. In both studies patients must have left ventricular systolic dysfunction (ejection fraction < or = 35%) determined by echocardiography. Each of the two studies are planned to enroll 1500 patients. Consecutive hospitalized patients with MI or CHF are screened in 37 Danish hospitals. Eligible patients are randomized to receive dofetilide or matching placebo. All patients are continuously monitored by telemetry for the first 3 days of the study to detect possible arrhythmic events and to ensure resuscitation in case of serious arrhythmias. Minimum duration of follow-up is 12 months. RESULTS: Between November 1993 and July 1996, a total of 5812 consecutive patients with CHF and 8688 consecutive patients with MI was screened for entry. Of these, 1518 patients were included in the CHF study and 1510 patients in the MI study. Overall 1-year mortality of randomized patients were 28 and 22%, respectively. CONCLUSION: DIAMOND will provide important data on the safety and efficacy of dofetilide in high-risk patients with left ventricular dysfunction and either CHF or MI, as well as evaluate tolerability in these populations.

Aged↗
PubMed2005

Identification of novel mutations in patients with Shwachman-Diamond syndrome.

Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive disease, mainly characterized by exocrine pancreatic insufficiency, hematological dysfunction and skeletal abnormalities. The SDS disease locus was mapped to chromosome 7q11 and disease-associated mutations were reported in the Shwachman-Bodian-Diamond syndrome (SBDS) gene. SBDS is a member of a highly conserved protein family with putative orthologs in diverse species including archaea and eukaryotes. It is widely expressed in many tissues and its function is still unknown. In the present study we analyzed the genotype of 15 unrelated Italian SDS patients. After sequencing the whole coding region we were able to complete all genotypes of the SDS patients tested. A total of eleven distinct mutations were identified. The most frequent mutations are due to gene conversion events between SBDS and its unprocessed pseudogene, named SBDSP. We described four new gene conversions involving exon 2 and three novel mutations that are not a result of gene conversion events. In two out of the fifteen cases, the family analysis evidenced an apparently unexpected inheritance of SDS alleles between parents and affected children. In the first case we found a new large gene conversion event, that caused the failure of the amplification of the father's allele and in the second what could be explained as a de novo gene conversion. Both cases have important implications for genetic counseling and molecular genetic analysis. In a disorder caused by gene conversions of variable extension these findings emphasize the necessity of testing patient's parents and the significance of the choice of primers.

Adolescent↗
PubMedDate not supplied

Application of the scatter diagram technique to the scanning electron microscope: preliminary results from diamond.

Using primary beam energies E0 ranging from 0.2 to 15 keV and an in-lens detector, a series of images of the same region of an artificial microstructured diamond sample have been acquired in scanning electron microscopy. Next, the images were analysed by using a scatter diagram technique to underline the topographic contrast change and contrast reversal. The results obtained from 0.5 to 15 keV are discussed with the help of an expression derived from the constant loss model for the secondary electron yield delta of diamond, but including the respective roles of the angle of incidence, i, and of the angle of detection, alpha. More surprising is the quality of images obtained at a beam energy as low as 0.2 keV, and more difficult to explain is the significant contrast change between 0.2 keV and 0.5 keV. For the first time, scatter diagrams are used as a diagnostic tool in scanning electron microscopy, and after some improvements it is hoped that the experimental approach followed here may lead to quantitative estimates of the local tilts of a specimen surface.

Journal Article↗
PubMed2000

A diamond-shaped zipper-like DNA architecture containing triads sandwiched between mismatches and tetrads.

The present study reports on the solution structure of the guanine plus adenine rich d(A(2)G(2)T(4)A(2)G(2)) 12-mer sequence which forms a unique fold in moderate NaCl solution. Proton resonance assignments for this sequence, which contains a pair of AAGG repeats separated by a T(4) linker segment, were aided by site-specific (15)N-labeling of guanine and adenine bases, as well as site-specific incorporation of 2,6-diaminopurine and 8-bromoadenine for adenine, 8-bromoguanine, 7-deazaguanine and inosine for guanine, and uracil and 5-bromouracil for thymine. The solution structure, which was solved by a combined NMR and intensity-refined computational approach, consists of a diamond-shaped architecture formed through dimerization of a pair of d(A(2)G(2)T(4)A(2)G(2)) hairpins. This 2-fold symmetric structure contains a quadruplex core consisting of a pair of symmetry-related G(syn).G(syn).G(anti). G(anti) tetrads, where adjacent strands have both parallel and anti-parallel neighbors and connecting T(4) segments which form diagonal loops. Each of the G(syn).G(syn).G(anti).G(anti) tetrads forms a platform on which stacks a T(anti).[A(syn)-A(anti)] triad containing a novel A(syn)-A(anti) platform step and a reversed Hoogsteen A(syn).T(anti) pair. We observe both base-base and base-sugar stacking interactions, with the latter occuring at a sheared A-G step where the sugar of the A stacks on the purine plane of the G. Unexpectedly, the topology of this sheared A(anti)-G(syn) step has many similarities with the C(anti)-G(syn) step in left-handed Z-DNA. The T.(A-A) triad is sandwiched between the G-tetrad on one side and a reversed Hoogsteen A(anti).T(anti) pair on the other. This intercalative topology is facilitated by a zipper-like motif where the A(anti) residue of the triad is interdigitated within a stretched A(anti)-G(syn) step. Our structural study reports on new aspects of A-A platforms, base triads, zipper-like interdigitation and sheared base steps, together with base-base and base-sugar stacking defining a diamond-like architecture for the d(A(2)G(2)T(4)A(2)G(2)) sequence. One can anticipate that mixed guanine-adenine sequences will exhibit a rich diversity of polymorphic architectures that will provide unique topologies for recognition by both nucleic acids and proteins.

DNA↗
PubMed1998

13C NMR Investigations of Spin-Lattice Relaxation in 99% 13C-Enriched Diamonds

The paper is devoted to investigations of spin-lattice relaxation processes in 99% 13C-enriched diamonds. Relaxation time measurements were performed as a function of orientation, magnetic field, and temperature. Both experimental results and theoretical discussion are presented. Multiexponential behavior of nuclear magnetization recovery was observed. There was found no significant influence of the diamond orientation on the nuclear spin-lattice relaxation. The field dependence of the spin-lattice relaxation time was found to be proportional to the second power of the magnetic field. The temperature measurements showed a weak increase of the spin-lattice relaxation time with decreasing temperature. Possible mechanisms of impurity relaxation are considered and compared with the experimental data. Copyright 1998 Academic Press. Copyright 1998 Academic Press

Journal Article↗
PubMed2002

Modification of diamond single crystals by chromium ion implantation with sacrificial layers.

Single-crystal diamond surfaces were implanted with chromium ions. Ion energies chosen were 120 and 180 keV. Ion doses of 1x10(17) cm(-2) were applied at a substrate temperature of 750 degrees C. Reduced lattice damage could be obtained by deposition of a titanium sacrificial layer with a thickness of 10 and 50 nm before implantation. Depth profiles of the elemental binding states were taken by photoelectron spectroscopy. The effect of the sacrificial layer thickness on diamond lattice damage was investigated by infrared spectroscopy.

Journal Article↗
PubMed2003

Autoerythrocyte sensitization (Gardner-Diamond) syndrome mimicking compartment syndrome.

We report a case with an unusual manifestation of autoerythrocyte sensitization syndrome (Gardner-Diamond syndrome). The patient had the clinical signs of compartment syndrome of the forearm requiring fasciotomy. Dermatological signs identical to Gardner-Diamond syndrome should alert the physician to avoid unnecessary fasciotomy, as these patients respond well to psychiatric treatment as in the present case.

Adult↗
PubMed2001

Autologous osteochondral transplantation using the diamond bone-cutting system (DBCS): 6-12 years' follow-up of 35 patients with osteochondral defects at the knee joint.

Thirty-five patients with severe osteochondral defects were treated by autologous osteochondral transplantation between 1986 and 1992. The majority of patients (27) suffered from osteochondrosis dissecans, while 8 patients presented with posttraumatic osteochondral defects. The grafts were harvested with a diamond bone cutter from the posterior part of the medial or lateral femoral condyle. In 29 patients the lesion was located at the lateral part of the medial femoral condyle, in 3 it was at the lateral femoral condyle, and in 3 at the patella. Twenty-nine patients could be examined at the follow-up between 6 and 12 years later (mean follow up 8.1 years). Using the standard cartilage evaluation form, the transplanted knees of 12 patients were graded as normal (grade I), 14 knees were nearly normal (grade II), while 3 patients presented with an abnormal result (grade III). All 3 of them had a varus malalignment and refused a high tibial correction osteotomy against our advice. No patient was assessed as severely abnormal (grade IV). The majority of patients improved their activity level and the functional status of the joint. Twelve patients developed new radiological signs of osteoarthrosis with a decrease in the radiological score of Kellgren and Lawrence by about one stage. We conclude that autologous osteochondral transplantation with the diamond bone-cutting system is an effective method in the treatment of severe osteochondral defects.

Adult↗
PubMed1999

Shwachman-Diamond syndrome: early bone marrow transplantation in a high risk patient and new clues to pathogenesis.

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterised by exocrine pancreas insufficiency, metaphyseal dysostosis and bone marrow dysfunction. Recurrent severe bacterial infections and susceptibility to leukaemia are the major causes of morbidity and mortality occurring preferentially in patients with pancytopenia and features of myelodysplasia. Here we report a patient with SDS leading to recurrent bacterial infections and a deteriorating condition since early infancy. Extensive investigations disclosed severe pancytopenia, myelodysplasia and a clonal cytogenetic abnormality, inv(14)(q11q32), as risk factors of leukaemic transformation. He therefore underwent allogeneic geno-identical bone marrow transplantation which resulted in correction of all haematological and immunological abnormalities within an 18-month follow up period. Conclusion Bone marrow transplantation may be considered early as a valuable treatment option especially in high risk Schwachman-Diamond syndrome patients anticipating malignant transformation, life-threatening severe infections or further organ damage.

Bone Marrow Diseases↗
PubMed1985

Diamond-Blackfan syndrome in adult patients.

Two adults with pure red cell aplasia are described. No extrinsic etiologic mechanisms were identified. Evidence of anemia was long-standing and varied in severity. Musculoskeletal abnormalities (webbed neck, Sprengel's and Klippel-Feil deformities, and hand abnormalities) were similar to those seen in the congenital form of red cell aplasia (Diamond-Blackfan syndrome). As in the congenital variety, adrenal cortical steroids resulted in hematologic repair. These observations suggest that congenital (Diamond-Blackfan) pure red cell aplasia may be first recognized in adulthood and that steroids provide a potential therapeutic modality.

Adult↗
PubMed1990

Diamond-shaped anastomosis for duodenal atresia: an experience with 44 patients over 15 years.

During the period between 1974 and 1988 44 patients were treated for congenital intrinsic duodenal obstruction using a diamond-shaped anastomosis (35 atresias, including two multiple atresias and nine stenoses). Neither gastrostomy nor transanastomotic tube was used. Postoperatively, oral feeding was started on days 2 to 6 (3.66 +/- 1.41 day). Intravenous fluid administration was discontinued on days 3 to 20 (7.54 +/- 3.58 day). Fourteen patients died, none related to the operative procedure. Of 30 survivors, 21 patients have been followed from 6 months to 15 years. Body weight was within the normal range at the latest visit. Current barium study performed in 19 patients showed no blind loop, megaduodenum, or anastomotic malfunction. The diamond-shaped anastomosis provides the following advantages: (1) early recovery of anastomotic function, and (2) avoidance of later complications, such as formation of a blind loop or anastomotic stenosis.

Anastomosis, Surgical↗
PubMed1989

From flintstone to diamond blade: a new multifunctional instrument for use in coronary surgery.

We report on the development and clinical application of a diamond surgical knife specially designed for the preparation, initial incision, and bidirectional enlargement of coronary arteries. The ergonomic design of the knife enables the performance of all the necessary steps in a coronary incision with a single instrument and obviates the need for different shaped knives and scissors during preparation. The lasting sharpness of the diamond blade results in a far cleaner, less traumatic, cutting edge as can be demonstrated by scanning electron micrographs of incised coronary walls after the use of various types of coronary knives and scissors.

Arteries↗
PubMed2005

Development of a low-pressure diamond anvil cell and analytical tools to monitor microbial activities in situ under controlled P and T.

We have designed a new low-pressure Diamond Anvil Cell (DAC), calibrated two novel pressure calibrants and validated the use of semi-quantitative Raman and X-ray spectroscopies to monitor the fate of microbes, their metabolism or their cellular components under controlled pressures and temperatures in the 0.1-1.4 GPa and 20-300 degrees C P,T range. The low-pressure DAC has a 250- to 600-microm-thick observation diamond window to allow for lower detection limits and improved microscopic imaging. This new design allows the determination of cellular growth parameters from automated image analysis, which can be correlated with the spectroscopic data obtained on metabolism, ensuring high quality data collection on microbial activity under pressure. The novel pressure sensors offer the ease of use of the well-known ruby scale, while being more sensitive and reacting to pressure variations instantaneously.

Bacteria↗
PubMed2005

Extended defect related energy loss in CVD diamond revealed by spectrum imaging in a dedicated STEM.

This article aims at investigations of the low EEL region in the wide band gap system diamond. The advent of the UHV Enfina electron energy loss spectrometer combined with Digital Micrograph acquisition and processing software has made reliable detection of absorption losses below 10 eV possible. Incorporated into a dedicated STEM this instrumentation allows the acquisition of spectral information via spectrum maps (spectrum imaging) of sample areas hundreds of nanometers across, with nanometers pixel sizes, adequate spectrum statistics and 0.3 eV energy resolution, in direct correlation with microstructural features in the mapping area. We aim at discerning defect related losses at band gap energies, and discuss different routes to simultaneously process and analyse the spectra in a map. This involves extracting the zero loss peak from each spectrum and constructing ratio maps from the intensities in two energy windows, one defect related and one at a higher, crystal bandstructure dominated energy. This was applied to the residual spectrum maps and their first derivatives. Secondly, guided by theoretical EEL spectra calculations, the low loss spectra were fitted by a series of gaussian distributions. Pixel maps were constructed from amplitude ratios of gaussians, situated in the defect and the unaffected energy regime. The results demonstrate the existence of sp2-bonded carbon in the vicinity of stacking faults and partial dislocations in CVD diamond as well as additional states below conduction band, tailing deep into the band gap, at a node in a perfect dislocation. Calculated EEL spectra of shuffle dislocations give similar absorption features at 5-8 eV, and it is thought that this common feature is due to sp2-type bonding.

Journal Article↗