Pre-transplant and longitudinal changes in faecal microbiome characteristics are associated with subsequent development of chronic graft-versus-host disease

The role of the gastrointestinal microbiome in predisposing to chronic graft-versus-host disease (cGVHD), an immune-mediated haematopoietic cell transplant (HCT) complication, is not well defined. We examined the relationship of the host faecal microbiome with subsequent cGVHD development by analysing baseline stool samples as well as post-HCT changes in microbiome composition and metabolite pathway analyses. We analysed pre-transplant baseline samples from 11 patients who subsequently developed cGVHD compared to 13 controls who did not develop acute GVHD or cGVHD at any time. We found a significant differential abundance of multiple taxa at baseline between cGVHD versus controls, including the Actinobacteria phylum and Clostridium genus. A subgroup analysis of longitudinal samples within each patient revealed a greater loss of alpha diversity from baseline to post-engraftment in patients who subsequently developed cGVHD. Metabolic pathways analysis revealed that two pathways associated with short-chain fatty acid metabolism were enriched in cGVHD patient microbiomes: β-oxidation and acyl-CoA synthesis, and γ-aminobutyrate shunt. In contrast, a tryptophan catabolism pathway was enriched in controls. Our findings show a distinct pattern of baseline microbiome and metabolic capacity that may play a role in modulating alloreactivity in patients developing cGVHD. These findings support the therapeutic potential of microbiome manipulation for cGVHD prevention.     

Automatic landmark identification in cone-beam computed tomography

Objective

To present and validate an open-source fully automated landmark placement (ALICBCT) tool for cone-beam computed tomography scans.

Materials and Methods

One hundred and forty-three large and medium field of view cone-beam computed tomography (CBCT) were used to train and test a novel approach, called ALICBCT that reformulates landmark detection as a classification problem through a virtual agent placed inside volumetric images. The landmark agents were trained to navigate in a multi-scale volumetric space to reach the estimated landmark position. The agent movements decision relies on a combination of DenseNet feature network and fully connected layers. For each CBCT, 32 ground truth landmark positions were identified by 2 clinician experts. After validation of the 32 landmarks, new models were trained to identify a total of 119 landmarks that are commonly used in clinical studies for the quantification of changes in bone morphology and tooth position.

Results

Our method achieved a high accuracy with an average of 1.54 ± 0.87 mm error for the 32 landmark positions with rare failures, taking an average of 4.2 second computation time to identify each landmark in one large 3D-CBCT scan using a conventional GPU.

Conclusion

The ALICBCT algorithm is a robust automatic identification tool that has been deployed for clinical and research use as an extension in the 3D Slicer platform allowing continuous updates for increased precision.     

Demographic and clinical characteristics of acute myeloid leukaemia diagnosed and treated at the tertiary level in Afghanistan

A retrospective case series design was conducted to elucidate the demographic features of acute myeloid leukaemia in Afghanistan. This study was conducted at Jamhuriat Hospital and French Medical Institute for Mothers and Children, Kabul, Afghanistan. A total of 203 patients with AML diagnosed and managed at Jamhuriat Hospital from 1 March 2018 to 31 March 2020, were included in the current study. The median age at diagnosis was 27 years. Housewives represented the largest subset of patients from an occupational point of view constituting 37.44% of the total sample population and 81.72% of the female population, followed by 20.69% patients who were students of which 14.77% were male and 5.91% were female, and 17.24% were farmers, which constituted 31.81% of the male population. Similarly, 69.95% of individuals presented with infection, 57.14% presented with bone tenderness, 46.3% presented with bleeding tendencies, 55.66% had hepatomegaly and/or splenomegaly, and 27.58% of patients had lymphadenopathy. Considering the chemotherapeutic regime, 64.53% of the individuals received standard 7 + 3 (cytarabine + daunorubicin) induction regimen, 10.68% of those received 5 + 2 re-induction chemotherapy (cytarabine + daunorubicin). 10.84% who were diagnosed with acute promyelocytic leukaemia received all-trans-retinoic acid + arsenic trioxide, while 5.42% of patients defaulted chemotherapy. High prevalence was noted in young individuals. Similarly, a high proportion of patients were constituted by housewives.     

Three-dimensional comparison of bone-borne and tooth-bone-borne maxillary expansion in young adults with maxillary skeletal deficiency

Objective

To compare the transverse dental and skeletal changes in patients treated with bone-anchored palatal expander (bone-borne, BB) compared to patients treated with tooth and bone-anchored palatal expanders (tooth-bone-borne, TBB) using cone-beam computer tomography (CBCT) and 3D image analysis.

Methods

The sample comprised 30 patients with transverse maxillary discrepancy treated with two different types of appliances: bone-borne (Group BB) and tooth-bone-borne (Group TBB) expanders. CBCT scans were acquired before (T1) and after completion of maxillary expansion (T2); the interval was 5.4 ± 3.4 and 6.2 ± 2.1 months between the T1 and the T2 scans of Group TBB (tooth-bone-borne) and Group BB (bone-borne), respectively. Transverse, anteroposterior and vertical linear and angular three-dimensional dentoskeletal changes were assessed after cranial base superimposition.

Results

Both groups displayed marked transverse skeletal expansion with a greater ratio of skeletal to dental changes. Greater changes at the nasal cavity, zygoma and orbital levels were found in Group BB. A relatively parallel sutural opening in an anterior–posterior direction was observed in Group TBB; however, the Group BB presented a somewhat triangular (V-shaped) opening of the suture that was wider anteriorly. Small downward-forward displacements were observed in both groups. Asymmetric expansion occurred in approximately 50% of the patients in both groups.

Conclusion

Greater skeletal vs dental expansion ratio and expansion of the circummaxillary regions were found in Group BB, the group in which a bone-borne expander was used. Both groups presented skeletal and dental changes, with a similar amount of posterior palate expansion. Asymmetric expansion was observed in both groups.