Microbial contamination of laboratory constructed removable orthodontic appliances.

OBJECTIVES: This study aims to determine whether laboratory constructed removable orthodontic appliances are free from microbial contamination prior to clinical use and to evaluate the dental hospital cross-infection procedures to ensure that patient-derived contamination does not enter the construction process, thereby propagating a cycle of cross-contamination. MATERIALS AND METHODS: The construction process of removable orthodontic appliances from three individuals was evaluated at every stage, from impression to final delivery of the appliance using molecular microbiological techniques. The bacterial profiles at each stage of appliance construction were obtained using denaturing gradient gel electrophoresis, along with the bacterial profiles of the three participants' saliva. This enabled the bacterial profiles found at each stage of construction to be compared directly with the saliva of the person for whom the appliance was being constructed. Bacteria were identified at each stage using 16S rDNA PCR amplification and sequence phylogeny. RESULTS: There was no evidence of bacterial cross-contamination from patients to the laboratory. The current process of disinfection of impression appears to be adequate. Contamination was found on the final removable appliances (0.97 × 10(2)-1.52 × 10(3) cfu ml(-1)), and this contamination occurred from within the laboratory itself. CONCLUSIONS: Every effort is made to reduce potential cross-infection to patients and dental professionals. Newly constructed removable appliances were shown not to be free from contamination with bacteria prior to clinical use, but this contamination is environmental. Further studies would be required to determine the level of risk this poses to patients. CLINICAL SIGNIFICANCE: Dental professionals have a duty of care to minimise or eradicate potential risks of cross-infection to patients and other members of the team. To date, much less attention has been paid to contamination from the orthodontic laboratory, so contamination and infection risks are unknown.

Endovascular treatment of cranial dural arteriovenous fistulae: a single-centre, 14-year experience and the impact of Onyx on local practise.

INTRODUCTION: Dural arteriovenous fistulae (DAVFs) are a potentially dangerous group of intracranial arteriovenous shunts with significant morbidity and mortality. Treatment has traditionally included transvenous and/or transarterial embolisation, which may be followed by surgical ligation. This study assesses the impact of Onyx on treatment. METHODS: Forty-nine consecutive patients referred for endovascular management of DAVFs between 1994 and 2008 were included in a retrospective, intention-to-treat analysis. DAVFs managed conservatively or purely surgically were excluded. Success rates and complications were compared between patients treated by transvenous, transarterial Onyx and transarterial non-Onyx material embolisation. RESULTS: Fifty-six separate DAVFs were detected in 49 patients. Embolisation of 52 DAVFs was performed or attempted. Transvenous sinus occlusion of ten type I or II DAVFs resulted in cure but was unsuccessful in a single type IV fistula and three of the four indirect carotico-cavernous fistulae treated in this way. Two type I and nine type III/IV were identified in the transarterial, non-Onyx group and three of 11 (27.3%) were cured. Amongst the six type II and 20 type III/IV DAVFs belonging to the transarterial Onyx group, cure was achieved in 17 of 26 (65.4%) rising to 72.7%, considering only those cases where the fistula could be accessed and Onyx was injected. CONCLUSIONS: The introduction of Onyx has improved the endovascular cure rate of DAVFs, particularly types III and IV. Advances in technology have made an endovascular approach the management of choice for the majority of DAVFs requiring treatment. Low complication rates are achievable.

The multidisciplinary management of hypodontia: a team approach.

Hypodontia is a frequently encountered condition within general dental practice. Its successful management involves the interplay of a number of clinicians. The general dental practitioner plays a key role in the management of patients. The aim of this short article is to outline some of the principles of the multidisciplinary management of hypodontia with an emphasis on orthodontic treatment.

Generation of retroviral vector for clinical studies using transient transfection.

Transient transfection of 293T cells was utilized to produce high-titer murine recombinant retroviral vectors for clinical studies. This system was initially optimized by gene transfer using different retroviral envelope proteins into activated human CD4+ T lymphocytes in vitro. Higher titer and infectivity were obtained than with stable murine producer lines; titers of 0.3-1 x 10(7) infectious units per milliliter for vectors encoding the green fluorescent protein (GFP) were achieved. Virions pseudotyped with envelope proteins from gibbon ape leukemia virus or amphotropic murine leukemia virus resulted in gene transfer of > or = 50% in CD4+ human T lymphocytes with this marker. Gene transfer of Rev M10 with this vector conferred resistance to HIV infection compared with negative controls in the absence of drug selection. Thus, the efficiency of transduction achieved under these conditions obviated the need to include selection to detect biologic effects in T cells. Finally, a protocol for the production of large-scale supernatants using transient transfection was optimized up to titers of 1.9 x 10(7) IU/ml. These packaging cells can be used to generate high-titer virus in sufficient quantities for clinical studies and will facilitate the rapid, cost-effective generation of improved retroviral, lentiviral, or other viral vectors for human gene therapy.

A prototype high-purity germanium detector system with fast photon-counting circuitry for medical imaging.

A data-acquisition system designed for x-ray medical imaging utilizes a segmented high-purity germanium (HPGe) detector array with 2-mm wide and 6-mm thick elements. The detectors are contained within a liquid-nitrogen cryostat designed to minimize heat losses. The 50-ns pulse-shaping time of the preamplifier electronics is selected as the shortest time constant compatible with the 50-ns charge collection time of the detector. This provides the detection system with the fastest count-rate capabilities and immunity from microphonics, with moderate energy resolution performance. A theoretical analysis of the preamplifier electronics shows that its noise performance is limited primarily by its input capacitance, and is independent of detector leakage current up to approximately 100 nA. The system experimentally demonstrates count rates exceeding 1 million counts per second per element with an energy resolution of 7 keV for the 60-keV gamma ray photon from 241Am. The results demonstrate the performance of a data acquisition system utilizing HPGe detector systems which would be suitable for dual-energy imaging as well as systems offering simultaneous x-ray transmission and radionuclide emission imaging.

Joint sepsis as a complication of sero-negative arthritis.

Septic arthritis is a recognised complication of rheumatoid arthritis but has not been well described in sero-negative spondarthritis. We report 3 patients with sero-negative inflammatory joint disease who developed joint sepsis early in the course of the disease. In none was there a recognisable source of infection. Two cases were complicated by osteomyelitis and in one the sepsis has been recurrent over thirty years.

Epistaxis as an unusual presentation of an antrochoanal polyp.

Antrochoanal polyps rarely present with severe epistaxis. We present the case of a young male patient who presented in such a manner, thus leading to the suspicion of an angiofibroma as the underlying pathology. The radiological investigations, treatment and pathological features are discussed.

Time-dependent recontamination rates of sterilised dental instruments.

OBJECTIVES: To determine time-related recontamination rates of sterilised instruments, following guidance from the UK Department of Health (HTM 01-05) that such instruments within primary dental care may only be stored for 60 days following sterilisation using a vacuum autoclave. MATERIALS AND METHODS: A total of 25 used examination mirrors underwent a washer-disinfector cycle, individual packaging and finally vacuum autoclaving. Immediately after autoclaving, time zero, five mirrors were tested for microbial contamination by aerobic and anaerobic culture. At 31, 60, 90 and 124 days a further five mirrors were removed from their packaging and were similarly tested for microbial contamination. RESULTS: There was no bacterial growth on blood-enriched media under both aerobic and anaerobic conditions after 5 days of incubation at 37°C at any time period from 0 to 124 days post-sterilisation. CONCLUSIONS: There was no recontamination of sterilised instruments in this investigation over the test period of 124 days. This exceeds the recommended limit of 60 days stated by the UK Department of Health. The new guidance, HTM 01-05, appears to place an extra burden on primary care dentists. This burden is not without associated costs, and at present does not appear to be based on published evidence.

Ganglioneuroma of the mandible resulting from metastasis of neuroblastoma.

Neuroblastoma, ganglioneuroblastoma and ganglioneuroma are neuroblastic tumours derived from primordial neural crest tissue. The authors report a rare presentation of a ganglioneuroma of the mandible arising from a metastasis of an adrenal neuroblastoma. The pathogenesis and behaviour of ganglioneuromas is discussed, together with recommendations for their management.

Peripheral cerebral aneurysm associated with a glioma.

This 42-year-old man with acute subarachnoid, intraventricular and parenchymal hemorrhage from an angiographically and surgically confirmed successfully clipped, right splenial artery aneurysm, subsequently manifested a grade 3 astrocytoma at the site of the aneurysm. Intracranial aneurysms are recognized in association with metastases from cardiac myxoma and choriocarcinoma, but are rarely seen with primary brain tumors. In patients with nontraumatic peripheral aneurysms it would seem prudent to biopsy the aneurysm and/or surrounding necrotic tissue at the time of surgical clipping.

Magnetic resonance imaging of intracranial cavernous angiomas: a report of 13 cases with pathological confirmation.

The magnetic resonance imaging features of 13 pathologically confirmed cavernous angiomas were retrospectively reviewed. T2-weighted images were found to be the most useful, the commonest appearance being a mixed signal intensity core with a complete peripheral rim of marked hypointensity. These appearances relate largely to various stages in the evolution of haemorrhage, although the presence of calcium and slowly flowing blood also contribute.

Spontaneous thrombosis of a cerebral arteriovenous malformation.

We report a patient who presented acutely to a neurosurgical unit with a mild left hemiparesis following mild trauma and an episode of hypotension. Computed tomography of the brain showed fresh partial thrombosis of a right parietal arteriovenous malformation. Subsequent angiography confirmed partial obliteration of an arteriovenous malformation. The malformation had completely thrombosed on follow up computed tomography, and disappeared angiographically.

Ultrasound of the palpable abdominal mass.

A retrospective study was made of adult patients with a palpable abdominal mass referred by Hospital Practitioners to the ultrasound department over an 11 month period. One hundred and four patients were included in the study. Sixty-nine patients had an abnormality responsible for the clinically palpable mass and 35 patients did not . There was one false positive ultrasound diagnosis and one false negative. The correct organ of origin was suggested in 60 patients and the correct pathological diagnosis in 53 patients. The high positive predictive value (99%) and negative predictive value (97%) for the presence or absence of a lesion in these patients compare very well with the investigation of such patients by computed tomography and we suggest that ultrasound should be the initial investigation.

Molecular cloning of the Mason-Pfizer monkey virus genome: biological characterization of genome length clones and molecular comparisons to other retroviruses.

The molecular cloning of the DNA provirus of Mason-Pfizer monkey virus (M-PMV) is described. Fourteen independent clones of integrated M-PMV proviruses were isolated from a human embryo kidney cell line that had been previously derived from a single cell clone infected with M-PMV. Characterization of these clones for size of insert, restriction pattern of flanking DNA, and presence of repetitive DNA in the flanking sequences revealed that 10 of the isolates were identical while the four remaining clones were unique. Three independent clones of unintegrated M-PMV proviruses containing a single copy of the long terminal repeat (LTR) were cloned from acutely infected human embryo kidney cells, Transfection assays revealed that 13 of 14 integrated proviruses and 2 of 3 unintegrated proviruses were capable of producing infectious virus. One of the integrated provirus clones (clone 6A) produced consistently higher titers of virus than all of the other clones in all assays used and in two different cell lines, indicating that it contained a mutation that enhances virus replication. The virus recovered after transfection was shown to be capable of inducing cell fusion in nontransformed cell lines, confirming that this property is associated with M-PMV. One of the clones was hybridized under conditions of varying stringency, to molecular clones of type B, C, and D retroviruses. These studies revealed M-PMV to be most closely related to squirrel monkey retrovirus (D-type virus) and more distantly related to mouse mammary tumor virus (B-type virus). Hybridization was also detected with clones from the pol gene region of a family of human endogenous sequences. No homology was detected with Rous sarcoma virus or most mammalian C-type viruses tested. The exceptions were baboon endogenous virus and RD114 in which previously identified homology in the env gene was confirmed. These results suggest that the type D and type B viruses can be linked together in a group of viruses of similar ancestral origin analogous to that recently proposed for the human T-cell leukemia viruses and bovine leukemia virus.

Specific growth stimulation by linoleic acid in hepatoma cell lines transfected with the target protein of a liver carcinogen.

The hepatic carcinogen N-2-fluorenylacetamide (2-acetylaminofluorene) was shown previously to interact specifically with its target protein, liver fatty acid binding protein (L-FABP), early during hepatocarcinogenesis in rats. In search of the significance of the interaction, rat L-FABP cDNA in the sense and antisense orientations was transfected into a subline of the rat hepatoma HTC cell line that did not express L-FABP. After the transfections, the basal doubling times of the cells were not significantly different. However, at 10(-5)-10(-7) M, linoleic acid, which is an essential fatty acid, a ligand of L-FABP, and the precursor of many eicosanoids and related lipids, stimulated the incorporation of [3H]thymidine in three randomly isolated and stably transfected cell clones that expressed L-FABP, but virtually did not stimulate the incorporation of [3H]thymidine in three L-FABP-nonexpressing clones transfected with the antisense DNA. Linoleic acid at 10(-6) M increased cell number almost 3-fold (38% vs. 14%; P less than 0.0001) and thymidine incorporation nearly 5-fold (23.2% vs. 4.9%; P less than 0.001) in the L-FABP-expressing cells compared to that in the transfected nonexpressing cells. L-FABP acted specifically and cooperatively with linoleic acid, inasmuch as all the proteins other than L-FABP in the transfected L-FABP nonexpressing cells and four other fatty acids (gamma-linolenic acid, dihomo-gamma-linolenic acid, arachidonic acid, and palmitoleic acid) were unable to effect a significant elevation or difference in the level of DNA synthesis that was attributable to the transfection. Metabolism of the linoleic acid to oxygenated derivatives was apparently necessary, since the cyclooxygenase inhibitor indomethacin partly inhibited and the antioxidant lipoxygenase inhibitors nordihydroguariaretic acid and alpha-tocopherol completely abolished the growth stimulation. The evidence supports the idea that L-FABP, the target protein of the liver carcinogen, acts specifically in concert with oxygenated metabolites of linoleic acid to modulate the growth of hepatocytes.

Trans-sphenoidal encephalocele in association with Dandy-Walker complex and cardiovascular anomalies.

We present a case of trans-sphenoidal encephalomeningocele in association with a posterior cranial fossa malformation which fulfils the criteria for the Dandy-Walker complex [1]. Congenital cardiovascular defects were also present. An abnormality of neural crest development may be responsible for the combined occurrence of these anomalies.

Can spontaneous spinal epidural haematoma be managed safely without operation? A report of four cases.

The presentation, investigation, and management of four patients with spontaneous spinal epidural haematoma is presented. In each case the diagnosis was made by MRI. At the time of diagnosis spontaneous recovery had started in each patient and therefore they were all treated conservatively. In each case follow up MRI confirmed rapid reduction in the size of the haematoma and no underlying cause was demonstrated. The presentation, diagnosis, and rationale for treatment are discussed. Conservative treatment is safe in some cases of spinal epidural haematoma if early neurological recovery has started.