Influence of dental materials on dental MRI

Objectives:

To investigate the potential influence of standard dental materials on dental MRI (dMRI) by estimating the magnetic susceptibility with the help of the MRI-based geometric distortion method and to classify the materials from the standpoint of dMRI.

Methods:

A series of standard dental materials was studied on a 1.5 T MRI system using spin echo and gradient echo pulse sequences and their magnetic susceptibility was estimated using the geometric method. Measurements on samples of dental materials were supported by in vivo examples obtained in dedicated dMRI procedures.

Results:

The tested materials showed a range of distortion degrees. The following materials were classified as fully compatible materials that can be present even in the tooth of interest: the resin-based sealer AH Plus^® (Dentsply, Maillefer, Germany), glass ionomer cement, gutta-percha, zirconium dioxide and composites from one of the tested manufacturers. Interestingly, composites provided by the other manufacturer caused relatively strong distortions and were therefore classified as compatible I, along with amalgam, gold alloy, gold–ceramic crowns, titanium alloy and NiTi orthodontic wires. Materials, the magnetic susceptibility of which differed from that of water by more than 200 ppm, were classified as non-compatible materials that should not be present in the patient’s mouth for any dMRI applications. They included stainless steel orthodontic appliances and CoCr.

Conclusions:

A classification of the materials that complies with the standard grouping of materials according to their magnetic susceptibility was proposed and adopted for the purposes of dMRI. The proposed classification can serve as a guideline in future dMRI research.     

Molecular surveillance of multidrug-resistant Gram-negative bacteria in Ukrainian patients,Germany, March to June 2022

BackgroundSince the beginning of the war in Ukraine in February 2022, Ukrainians have been seeking shelter in other European countries.AimWe aimed to investigate the prevalence and the molecular epidemiology of multidrug-resistant Gram-negative (MDRGN) bacteria and meticillin-resistant Staphylococcus aureus (MRSA) in Ukrainian patients at admittance to the University Hospital Frankfurt, Germany.MethodsWe performed screening and observational analysis of all patients from March until June 2022. Genomes of MDRGN isolates were analysed for antimicrobial resistance, virulence genes and phylogenetic relatedness.ResultsWe included 103 patients (median age: 39 ± 23.7 years), 57 of whom were female (55.3%; 95% confidence interval (CI): 45.2–5.1). Patients were most frequently admitted to the Department of Paediatrics (29/103; 28.2%; 95% CI: 19.7–37.9). We found 34 MDRGN isolates in 17 of 103 patients (16.5%; 95% CI: 9.9–25.1). Ten patients carried 21 carbapenem-resistant (CR) bacteria, five of them more than one CR isolate. Four of six patients with war-related injuries carried eight CR isolates. In six of 10 patients, CR isolates caused infections. Genomic characterisation revealed that the CR isolates harboured at least one carbapenemase gene, bla _NDM-1 being the most frequent (n = 10). Core genome and plasmid analysis revealed no epidemiological connection between most of these isolates. Hypervirulence marker genes were found in five of six Klebsiella pneumoniae CR isolates. No MRSA was found.ConclusionHospitals should consider infection control strategies to cover the elevated prevalence of MDRGN bacteria in Ukrainian patients with war-related injuries and/or hospital pre-treatment and to prevent the spread of hypervirulent CR isolates.     

Characterization of hyaluronan and TSG‐6 in skin scarring: differential distribution in keloid scars,normal scars and unscarred skin

Background Hyaluronan (HA) is a major component of the extracellular matrix (ECM) with increased synthesis during tissue repair. Tumour necrosis factor‐stimulated gene‐6 (TSG‐6) is known to catalyze the covalent transfer of heavy chains (HC1 and HC2) from inter‐α‐inhibitor (IαI) onto HA, and resultant HC?HA complexes have been implicated in physiological and pathological processes related to remodelling and inflammation. Objective The aims of this study were to determine the expression of HA, TSG‐6 and the IαI polypeptides in unscarred skin, normal scars and keloid scars. Methods Formalin‐fixed paraffin‐embedded sections of unscarred skin, normal scars and keloid scars were prepared from patient samples collected during scar revision surgery. Haematoxylin and eosin, as well as immunofluorescent staining for HA, TSG‐6 and the three polypeptide chains of IαI (i.e. HC1, HC2 and bikunin) were performed. Results All skin types stained positive for TSG‐6, HC1, HC2 and bikunin, associated with keratinocytes, fibroblasts and skin appendages all in close proximity to HA. Keloid lesions showed altered HA organization patterns compared with unscarred skin and normal scars. TSG‐6 staining was significantly more intense in the epidermis compared with the dermis of all sample types. There was a significant reduction in TSG‐6 levels within keloid lesions compared with the dermis of unscarred skin (P = 0.017). Conclusion TSG‐6 is expressed in unscarred skin, where its close association with HA and IαI could give rise to TSG‐6‐mediated HC?HA formation within this tissue. A reduction in the beneficial effects of TSG‐6, caused by diminished protein levels in keloid lesions, could contribute to this abnormal scarring process.     

Recurrence of unexpected infant death

Families which had experienced two or more unexpected infant deaths were the subject of detailed confidential enquiries, including necropsy examination. Cases were derived from two main sources: first, deaths occurring during a nationwide programme of support for families with a subsequent baby (8 families) plus 2 families from a scries of confidential enquiries in Sheffield, and second, direct referrals from paediatricians (17 families). Fifty-seven deaths were studied. Twenty-four families had experienced 2 and three had experienced 3 deaths: 11 deaths (19%) were found to be adequately explained by history or post-mortem findings; 7 (12%) were probably accidental; 31 (55%) were most probably due to an action by one of the parents (filicide); only 5 (9%) were considered to be true or idiopathic sudden infant death syndrome; in 3 (5%) cases there was insufficient information to draw a conclusion. Five (18%) of the families lived in circumstances of serious social deprivation. A history of psychiatric illness was present in one or both parents in 18 (67%) of the families.     

Psoralen–ultraviolet A vs. narrow-band ultraviolet B phototherapy for the treatment of vitiligo

BACKGROUND: Although many treatment modalities have been tried for the treatment of vitiligo, none is uniformly effective. Psoralen phototherapy (psoralen ultraviolet A (PUVA)) is established as efficacious treatment for vitiligo. Recently, narrow-band UVB (NBUVB) has been reported to be an effective and safe therapeutic option in patients with vitiligo. OBJECTIVE: To compare the efficacy of PUVA and NBUVB in the treatment of vitiligo. DESIGN AND SETTING: Retrospective analysis of 69 patients with vitiligo who were treated either with PUVA or NBUVB at the pigmentary clinic of the Dermatology Department of the Postgraduate Institute of Medical Education and Research, Chandigarh, India. OUTCOME MEASURES: The following variables were compared between the two groups of patients: repigmentation status, number of treatments for marked to complete repigmentation in existing lesions, appearance of new lesions or increase in size of existing lesions, adverse effect of therapy, stability of repigmentation and colour match. RESULTS: In PUVA-treated group, 9 patients showed marked to complete repigmentation (23.6%) and 14 patients showed moderate improvement (36.8%), whereas in NBUVB-treated group, 13 patients showed marked to complete repigmentation (41.9%) and 10 patients showed moderate improvement (32.2%). A statistically significantly better stability and colour match of repigmentation with surrounding skin was seen in NBUVB-treated patients. CONCLUSION: We showed that NBUVB is more effective than PUVA and repigmentation induced with NBUVB is statistically significantly more stable.