Trends in CBCT current practice within three UK paediatric dental departments.

INTRODUCTION: Cone beam computed tomography (CBCT) is used across all dental specialties and has a number of advantages compared to 2D images. The SEDENTEXCT guidelines provide a number of indications for the use, however there are currently no specific guidelines for paediatric dentistry. The aim of this study was to assess current practice of CBCT imaging within paediatric dental departments in England, audit compliance of CBCT justifications against the standards set by SEDENTEXCT and assess whether the use of CBCT affected the treatment plan for each individual patient. METHODS: From the retrospective analysis of CBCT examinations taken over a 4-year period across three dental hospitals in the north of England, the following data were collected: age at the time of exposure, clinical indication, region of interest (ROI) and diagnostic findings. Clinical notes were also used to identify whether the CBCT had an effect on the final treatment plan. RESULTS: A total of 335 CBCT examinations were performed, mean age: 11 years. The number of CBCTs increased each year with a twofold increase in the first 2 years. The main clinical indication in 46% of CBCT examinations was the assessment of localised developing dentition, 68% were in the upper anterior sextant and 61% of CBCT exams were in the mixed dentition age group. The investigations were justified in 100% of the cases. CONCLUSION: The quantity of CBCT examination in paediatric dental patients is increasing to assist treatment planning but more often to enable improved surgical planning.

Comparison of the efficacy of a standard inferior alveolar nerve block versus articaine infiltration for invasive dental treatment in permanent mandibular molars in children: a pilot study.

AIM: To determine whether there is a clinical difference between an inferior dental block (IDB) using 2% lidocaine and a buccal infiltration (BI) using 4% articaine, when anaesthetising mandibular first permanent molars in children. METHODS: Patients aged 8-15 years who required invasive dental treatment on a lower molar tooth were randomised. The patient and dental operator were blind to the type of LA used. The patient used a visual analogue scale to record their experience of pain during injection and treatment. RESULTS: Twenty six teeth were anaesthetised (13 articaine, 13 lidocaine). When using an IDB, all treatment was completed successfully. On one occasion, anaesthesia was deemed unsuccessful when using a BI of articaine. There was no statistical difference in the mean VAS for the perceived pain of injection or treatment. CONCLUSION: This study showed that invasive dental treatment on a mandibular molar tooth can be completed successfully in children using a BI of articaine. In addition, the perceived pain of injection and treatment when using a BI of articaine is comparable to an IDB with lidocaine.

Trisomy 21 and isodicentric chromosome 21 in Kostmann syndrome following treatment with G-CSF.

A child with Kostmann syndrome, or severe congenital neutropenia, developed myelodysplastic syndrome after 6 years of treatment with rhG-CSF. The bone marrow karyotype showed acquired trisomy 21, and in some cells pentasomy 21 due to two isodicentric chromosomes 21. This is the second report of a patient with Kostmann syndrome and acquired trisomy 21.

Identification of new Fas mutations in a patient with autoimmune lymphoproliferative syndrome (ALPS) and eosinophilia.

Autoimmune lymphoproliferative syndrome (ALPS) is a rare, newly recognized, chronic lymphoproliferative disorder in children and is characterized by lymphadenopathy, splenomegaly, pancytopenia, autoimmune phenomena and expansion of double-negative (DN) T lymphocytes (TCR alpha beta+, CD4-, CD8-). Defective lymphocyte apoptosis caused by mutations of the Fas (CD95) gene has been linked in the pathogenesis of ALPS, as binding of Fas-ligand to Fas can trigger apoptosis. Of the ALPS cases reported to date, point mutations, frameshifts and silent mutations in Fas all have been identified. We report two new point mutations in Fas in a child with ALPS and eosinophilia; studies on other family members established the pattern of inheritance for these mutations. Flow cytometric analysis of blood and tissues (spleen, lymph node, bone marrow) revealed abnormally expanded populations of DN T lymphocytes. Furthermore, activated lymphocytes and IFN gamma-activated eosinophils were resistant to Fas-mediated apoptosis. Eosinophil resistance to Fas-mediated apoptosis has not been previously described in ALPS. Sequencing of Fas revealed two separate mutations not previously reported. One mutation, a C to T change at base 836, was a silent mutation inherited from the mother, while the second mutation, a C to A change at base 916, caused a non-conservative amino acid substitution in the death domain of Fas, changing a threonine to a lysine. This mutation is associated with a predicted change in the structure of a part of the death domain from a beta-pleated sheet to an alpha-helix. We speculate that the mutation in the death domain prevents the interaction of Fas with intracellular mediators of apoptosis and is responsible for the autoimmune manifestations of ALPS and the abnormal lymphocytosis and eosinophilia in this patient.

Cutaneous toxicity following the administration of dactinomycin.

Dactinomycin (AMD) is an effective drug in the management of several malignant disorders and has been used for almost 40 years. Skin and subcutaneous toxicities following extravasation are well known and can be harmful. Similarly radiation-recall is a well established phenomenon following the administration of AMD. We report a patient who developed a localized brawny erythema in the crural folds and the axillae, likely due to AMD. This rare skin complication of AMD seems to benefit from topical corticosteroid treatment, although postinflammatory hyperpigmentation may take months to disappear.

Partially mismatched blood cell transplants for high-risk hematologic malignancy.

Eleven patients with high-risk hematologic malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from partially mismatched family members in whom progenitor cells had been mobilized by G-CSF. Donors were mismatched by up to one antigen in the GVH direction and up to three antigens in the rejection direction. Outcomes were compared with those of 22 patients receiving BCT from fully matched donors. Two mismatched patients died without engraftment on day 21 and 32. One had rejected bone marrow from the same donor, the other was mismatched by two antigens in the rejection direction and received the lowest dose of CD34+ cells. Median time to granulocyte engraftment was 21.5 (range 16-33) days for the mismatched group compared with 16 (11-28) days for the matched group (P = 0.01). No correlation was found between CD34+ cell dose and time to granulocyte or platelet recovery. In the mismatched and matched BCT groups respectively, the risk of grade II-IV acute graft-versus-host disease (GVHD) was 73% vs 28% (P = 0.001) and of chronic GVHD 100% vs 78% at 18 months (P = 0.01). The relationship of T cell dose to acute GVHD could only be evaluated in the matched group and no correlation was found. One of 11 mismatched patients and eight of 22 matched patients had relapse or persistent disease. Disease-free survival at 1 year was similar at 55% for mismatched and 50% for matched BCT. These results indicate that allogeneic BCT from partially mismatched family members is accompanied by a high incidence of GVHD but may result in comparable survival to BCT from fully matched donors.

Second allogeneic transplants for leukemia using blood instead of bone marrow as a source of hemopoietic cells.

There is increasing interest in blood cell transplants (BCT) from normal donors as an alternative to BMT. Ten patients with relapsed or persistent leukemia after BMT received intensive cytotoxic conditioning followed by allogeneic BCT. Three BCT were from single-antigen mismatched donors; two of the corresponding recipients had rejected a BMT from the same donor. Two patients received BCT from a different donor (one matched, one single-antigen mismatched). The other six BCT were from the same, fully matched, bone marrow donors. Donors were given G-CSF to mobilize progenitor cells which were collected by a single 2-4 h leukapheresis. Methotrexate, CsA and folinic acid were used for GVHD prophylaxis for all transplants but CsA was discontinued sooner after BCT than after BMT. One patient died without engraftment having rejected a BMT from the same single-antigen mismatched donor 4 years previously. Nine patients had granulocyte recovery at a median of 14 days, up to 6 days faster than with their previous BMT. Platelet recovery was also 2-6 days faster than with BMT in four previously engrafting patients. Four patients died without platelet recovery after BCT within a year of BMT, three of treatment-related toxicity and one of relapse. Two patients developed grade II acute GVHD. Of six patients given BCT more than a year from BMT, four, all with acute leukemia, survive 7, 14, 29 and 29 months after BCT and one relapsed at 7 months. All four survivors developed chronic GVHD. These results indicate that BCT may be useful therapy for relapse occurring more than a year after BMT.

Allogeneic blood cell transplants for haematological malignancy: preliminary comparison of outcomes with bone marrow transplantation.

Twenty-six patients with haematological malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from five- or six-antigen matched siblings in whom progenitor cells had been mobilized by G-CSF. Outcomes were compared with a historical control group of 26 BMT patients matched for age and disease status. Granulocyte counts recovered to 0.5 x 10(9)/l in a median of 16 days after BCT compared with 21.5 days after BMT (P = 0.0002). Platelet counts, unsupported for 3 days, reached 20 x 10(9)/l in a median of 14 days vs 20.5 days (P = 0.0003) after BCT compared with BMT in those patients who engrafted. In the BCT and BMT groups, respectively, the risk of grade II-IV acute GVHD was 37 vs 21% (P = 0.16) and of chronic GVHD at 1 year 53 vs 48% (P = 0.9). There was no significant difference in red cell transfusions but BCT patients required fewer platelet transfusions (median 3 vs 5, P = 0.015) and fewer days in hospital (20.5 vs 25, P = 0.02). These results indicate that allogeneic BCT from matched and partially mismatched family donors result in faster engraftment than BMT without a significant increase in GVHD. Allogeneic BCT may prove to be a more tolerable procedure than BMT for both donor and recipient and there are indications of improved cost-effectiveness.

8;20 chromosomal translocation in a case of acute leukemia. Cytogenetic, immunophenotypic, ultrastructural, and molecular characteristics.

An 8;20 chromosomal translocation was observed in the leukemia cells of a 3-year-old girl. To our knowledge, this is the first report of this translocation in de novo acute leukemia. This chromosomal defect was present in the leukemia cells at diagnosis and also at relapse, but remission bone marrow cells had the 46,XX karyotype. By morphologic and cytochemical criteria the leukemia was myeloid but these features were more lymphoid when the leukemia recurred. However, the immunophenotype was consistent with myeloid leukemia and did not change at relapse. No evidence for either immunoglobulin or TCR gene rearrangement was observed.

Chromatin structural analysis of the 5' end and contiguous flanking region of the myeloperoxidase gene.

Myeloperoxidase (MPO) synthesis is known to be associated with the promyelocyte stage of myeloid differentiation. In particular the downregulation of MPO gene transcription is associated with myeloid cell maturation. We examined the changes in the deoxyribonuclease I hypersensitive sites within the 5' end of the MPO gene and its 5' flanking region during dimethyl sulfoxide (DMSO)-induced differentiation of HL-60 cells to determine the changes in chromatin structure that accompany this process. The locations of hypersensitive sites surrounding the 5' end of the gene in proliferating, uninduced cells were determined: three were observed in the 5' flanking region and one within the gene. Progressive changes in all sites accompanied the downregulation of MPO transcription after treatment with DMSO. No evidence of hypersensitivity was observed in the chromatin region examined after 8 days of DMSO exposure. The results provide an example of the changes that occur in the chromatin structure of a gene as it is inactivated during differentiation.

Histamine excites arcuate neurons in vitro through H1 receptors.

The electrophysiological effects of histamine on neurons of the hypothalamic arcuate nucleus of the female rat were tested with extracellular single unit recordings in an in vitro slice preparation. Histamine increased the spontaneous neuronal firing rate in 63% of the arcuate cells tested. An inhibitory response to histamine was seen in only one of the 117 neurons tested. The excitatory response to histamine showed dose dependency and was stable during synaptic blockade (by high magnesium and low calcium concentrations) and across a temperature range of 29-37 degrees C. Administration of histaminergic type 1 (pyrilamine and chlorpheniramine) and type 2 (cimetidine) receptor blockers revealed that the excitatory responses to histamine were mediated by type 1 receptors. The same neurons were also tested for responses to norepinephrine, serotonin, acetylcholine and substance P. A significant correlation was found between responses to histamine and substance P: all units excited by substance P were also excited by histamine. This subclass of histamine-responsive arcuate neurons may play a role in the regulation of the anterior pituitary, since histamine and substance P have similar effects on LH and prolactin secretion.

Interaction of Hoechst 33258 with repeating synthetic DNA polymers and natural DNA.

Fluorescence, circular dichroism and sedimentation through cesium chloride gradient techniques were performed to study the physical properties of the binding of the bisbenzimidazole dye Hoechst 33258 (H33258) to natural DNAs and synthetic polynucleotides of defined repeating units. These studies show that Hoechst 33258 exhibits at least two modes of interaction with duplex DNA: (1) a strong base pair specific mode which requires at least 4 consecutive AT base pairs and (2) a weaker mode of binding which is significantly reduced in the presence of high salt (0.4 M NaCl) and exhibits no apparent base specificity. The H33258 binding was found to be sensitive to the substitutions in the minor groove elements of a series of synthetic polynucleotides supporting the model of H33258 binding in the minor groove of the DNA with AT rich sequences. Similar mode of binding was predicted in natural DNAs by methylation of dye-DNA complexes. Footprint analysis of the complex of dye to a pBR322 fragment also supports that a minimum of 4 consecutive AT base pairs are required for H33258 binding to DNA.

Dynamic pituitary and ovarian changes occurring during the anestrus to estrus transition in the golden hamster.

Anestrous hamsters exhibit daily afternoon gonadotropin and progesterone surges, but little estrogen secretion. In the first experiment, short day anestrous females were transferred to long days to detect hormonal changes associated with recovery of cyclicity. Morning and afternoon blood samples were taken at increasing durations in long days. Females autopsied at their first vaginal estrus after transfer to long days differed from long day estrous controls only in their lower uterine weights. Some females at all durations exhibited signs of recovery, though they had not yet shown estrus. They did not display afternoon gonadotropin surges and had low circulating progesterone but high estradiol levels, stimulated uteri, and enhanced follicular development. Results of the second and third experiments provided evidence that the daily gonadotropin surges are not the cause per se of anestrus, and that changes in estrogen secretion are essential for the transition to and from anestrus. Phenobarbital blockade of the daily surges in anestrous females did not result in increased follicular growth and estrogen secretion. Furthermore, daily afternoon injections of gonadotropins it appears that the daily surges in anestrous hamsters simply reflect low estradiol levels. It is still not known what signal promotes rapid follicular maturation during the recovery from anestrus. Once initiated, however, this recovery appears to occur within a few days, with a rapid cascade of events. First, follicular development and estrogen secretion resume, and the daily LH surges cease. Then, progesterone levels decline, and an ovulatory surge of gonadotropins is triggered.

Shifts in gonadotropin and steroid levels that precede anestrus in female golden hamsters exposed to a short photoperiod.

Female golden hamsters exposed to short photoperiods become anestrous and exhibit daily surges of gonadotropins and progesterone. Since little is known about the transition between the cycling and anovulatory states, the following experiments were done to determine whether there are hormonal changes that precede cessation of estrous cyclicity. Females killed on the morning of estrus, up to the tenth estrous cycle in short days, showed no hormonal or ovarian morphologic evidence of changes in reproductive function. When assessed on the afternoon of estrus, however, serum levels of luteinizing hormone and progesterone increased significantly before vaginal and ovarian cyclicity ceased. Females sampled in both the morning and afternoon at increasing durations since their last vaginal estrus revealed that maximal daily surges of both gonadotropins and progesterone were not consistently manifested until the vaginal cycle had been absent for 2 weeks. By then, estrogen levels and uterine weights were low and ovaries showed hypertrophied interstitia and arrested follicular growth. We have demonstrated that there are hormonal changes in females before the loss of the vaginal cycle and onset of major daily hormonal surges. Our results suggest that alterations in feedback relationships between steroid hormones and gonadotropins may precede photoperiod-induced anestrus.

Effect of steroid treatment on tonic and surge secretion of LH and FSH in the female golden hamster: effect of photoperiod.

The purpose of these experiments was to determine whether daily gonadotropin surges that occur in intact or ovariectomized hamsters kept in short days (less than 12 h of light/day) are manifest because of extremely low levels of steroids. Hamsters were ovariectomized and placed in 16L:8D or 10L:14D. After 10-13 weeks, animals in each photoperiod were divided among four treatment groups: estradiol implant plus progesterone injection 5 days later; estradiol implant plus water injection; empty implant plus progesterone injection; empty implant plus water injection. Blood samples were taken from animals in the morning and afternoon before and after various treatments. In animals not receiving estradiol, all short-day and some long-day females showed low morning values of LH and surge values in the afternoon. Estrogen suppressed morning and enhanced afternoon values of LH in long-day animals, intensifying the surge. However, in the presence of estrogen, these LH surges eventually diminished in both photoperiods. Progesterone hastened the loss of the LH surge. Hamsters did not consistently demonstrate FSH surges until treated with estrogen. Serum FSH in untreated hamsters was much higher in long-day than in short-day animals. Treatment with both steroids maximally suppressed morning and afternoon FSH levels in all hamsters. Thus, in the absence of estrogen, circadian expression of LH surges always occurs in short days; FSH surges sometimes occur. In all animals showing spontaneous or estrogen-induced surges, estrogen eventually leads to inhibition of gonadotropin secretion, particularly in the presence of progesterone.(ABSTRACT TRUNCATED AT 250 WORDS)

Natural occurrence of left-handed (Z) regions in PM2 DNA.

Bacteriophage PM2 DNA, a ccc genome of high apparent superhelical density, contains left-handed (Z) regions as detected by competitive radioimmunoassay, agarose gel electrophoresis of DNA: antibody complexes and immunoelectron microscopy. The latter technique, in conjunction with partial blockage of restriction endonuclease sites by bound antibody, was used to map the left-handed regions along the DNA molecule. A cluster of four to five antibody molecules (approximately 25% of bound antibody) was located within map units 0.05-0.18 of the single Hpa II restriction site. Sequence analysis of part of this region showed the presence of several areas of high alternating purine-pyrimidine content. A strong correlation is observed between alternating pyrimidine-purine tracts of significant length and antibody binding sites.

Left-handed DNA: from synthetic polymers to chromosomes.

The interconversions between right-handed (R) and left-handed (L) helical conformations of DNA have been assessed by spectroscopic, electrophoretic, immunochemical, and enzymatic techniques. We have screened salt and solvent conditions which facilitate these transitions, as well as certain chemical modifications of the bases and backbone of defined synthetic polynucleotides. These include major and minor groove substituents as well as phosphorothioate analogues of selected phosphodiester bonds. We have established: R-L transitions in poly[d(G-C)] with iodo, bromo, methyl, and aza substitutions at the C5 position of cytosine, or phosphorothioate modification of the dGpC linkage. R-L transitions in the [d(A-C).d(G-T)]n sequence family using polymers modified as in the case of poly[d(G-C)]. The isomerizations are highly salt and temperature dependent. a possible L form of poly[d(A-T)] substituted with 2-amino adenine. the immunogenicities of constitutive and facultative Z-DNAs. the recognition specificities of different anti-Z-DNA IgGs for the spectrum of available polynucleotide probes. Some IgGs are sequence-specific. stabilization by IgG of otherwise transient left-handed conformations. anti-Z-DNA IgG binding to acid-fixed polytene chromosomes from the Diptera Drosophila, Chironomus, and Glyptotendipes. Laser scanning microscopy shows a maximal binding of 1 IgG per 3000-15,000 basepairs in acid fixed preparations. anti-Z-DNA IgG binding to negatively supercoiled plasmid, viral, phage, and recombinant closed circular DNAs. transcription from Z and Z* (associated) left-handed templates. From these and other results we propose that Z*-DNA may have important structural-functional roles in the cell.

Exercise reverses photoperiodic anestrus in golden hamsters.

In contrast to the inhibitory effects of endurance exercise on reproductive function in women athletes, voluntary running induces estrous cyclicity in anestrous female hamsters maintained in the nonstimulatory short-day photoperiod. Increased concentrations of circulating prolactin (Prl) seen in these animals are not responsible for the reversal of photoperiodic anestrus as demonstrated by experimental manipulations of prolactin secretion. Voluntary running also facilitates growth hormone (GH) release and somatic growth in hamsters independently of the photoperiod. Thus, it appears that endurance exercise can have facilitatory as well as inhibitory effects on the reproductive function in female mammals.