Carbohydrate knowledge, lifestyle and insulin: an observational study of their association with glycaemic control in adults with type 1 diabetes.

BACKGROUND: The ability to achieve optimal glycaemic control varies widely among individuals with type 1 diabetes. The present study aimed to explore the factors that are associated with optimal glycaemic control compared to suboptimal control. METHODS: An observational study design was used to explore the association of various factors with glycaemic control. Surveys were completed by individuals who attended the type 1 diabetes clinic at a tertiary hospital in New South Wales (NSW), Australia. Clinical and demographic information and attendance at dietary review were also collected. RESULTS: One hundred and three individuals completed the survey. Those with optimal control [glycated haemoglobin ≤7.0% (53 mmol mol-1 )] had a significantly shorter mean (SD) duration of diabetes [10.1 (12.6) years versus 18.8 (12.8) years, P = 0.005), were less likely to omit basal and bolus insulin (18.2% versus 47.5%, P = 0.016; 36.4% versus 61.8%, P = 0.034, respectively), and were less likely to report low confidence in managing their diabetes (9.1% versus 35.4%, P = 0.017). Participants who were able to identify carbohydrate sources were significantly more likely to have attended dietary review in the past 12 months (60.5% versus 20.0%, P = 0.001). However, they were not more likely to have better glycaemic control. CONCLUSIONS: The present study identified that consistency in taking insulin and confidence in self-management was associated with better glycaemic control. An association was also found between recent dietary review and better carbohydrate knowledge, although this did not translate into better glycaemic control. Future investigation into the application of carbohydrate knowledge is required.

Reversing immunosuppression in the tumor microenvironment of fibrolamellar carcinoma via PD-1 and IL-10 blockade.

Fibrolamellar carcinoma (FLC) is a rare liver tumor driven by the DNAJ-PKAc fusion protein that affects healthy young patients. Little is known about the immune response to FLC, limiting rational design of immunotherapy. Multiplex immunohistochemistry and gene expression profiling were performed to characterize the FLC tumor immune microenvironment and adjacent non-tumor liver (NTL). Flow cytometry and T cell receptor (TCR) sequencing were performed to determine the phenotype of tumor-infiltrating immune cells and the extent of T cell clonal expansion. Fresh human FLC tumor slice cultures (TSCs) were treated with antibodies blocking programmed cell death protein-1 (PD-1) and interleukin-10 (IL-10), with results measured by cleaved caspase-3 immunohistochemistry. Immune cells were concentrated in fibrous stromal bands, rather than in the carcinoma cell compartment. In FLC, T cells demonstrated decreased activation and regulatory T cells in FLC had more frequent expression of PD-1 and CTLA-4 than in NTL. Furthermore, T cells had relatively low levels of clonal expansion despite high TCR conservation across individuals. Combination PD-1 and IL-10 blockade signficantly increased cell death in human FLC TSCs. Immunosuppresion in the FLC tumor microenvironment is characterized by T cell exclusion and exhaustion, which may be reversible with combination immunotherapy.

Comprehensive assessment of HIV target cells in the distal human gut suggests increasing HIV susceptibility toward the anus.

BACKGROUND: Prevention of rectal HIV transmission is a high-priority goal for vaccines and topical microbicides because a large fraction of HIV transmissions occurs rectally. Yet, little is known about the specific target-cell milieu in the human rectum other than inferences made from the colon. METHODS: We conducted a comprehensive comparative in situ fluorescence study of HIV target cells (CCR5-expressing T cells, macrophages, and putative dendritic cells) at 4 and 30 cm proximal of the anal canal in 29 healthy individuals, using computerized analysis of digitized combination stains. RESULTS: Most strikingly, we find that more than 3 times as many CD68 macrophages express the HIV coreceptor CCR5 in the rectum than in the colon (P = 0.0001), and as such rectal macrophages seem biologically closer to the HIV-susceptible CCR5 phenotype in the vagina than the mostly HIV-resistant CCR5 phenotype in the colon. Putative CD209 dendritic cells are generally enriched in the colon compared with the rectum (P = 0.0004), though their CCR5 expression levels are similar in both compartments. CD3 T-cell densities and CCR5 expression levels are comparable in the colon and rectum. CONCLUSIONS: Our study establishes the target-cell environment for HIV infection in the human distal gut and demonstrates in general terms that the colon and rectum are immunologically distinct anatomical compartments. Greater expression of CCR5 on rectal macrophages suggests that the most distal sections of the gut may be especially vulnerable to HIV infection. Our findings also emphasize that caution should be exercised when extrapolating data obtained from colon tissues to the rectum.

A metabolic force for gene clustering.

Bacterial chromosomes frequently contain arrays of contiguous genes that group according to related metabolic roles. We propose that clustering of genes for metabolically related functions confers thermodynamic advantage to the organism based upon our protein immobility model (PIM) of intracellular diffusion. This thermodynamic effect provides the selection force argument that is missing from previous models of gene clustering. The PIM posits that clustered genes produce local clusters of enzymes in bacteria owing to the co-linearity of transcription and translation, and to the relative immobility of large proteins released into the cytosol. We maintain that the resulting physical proximity of enzymes for related pathway steps minimizes the steady state level of reaction step intermediates and thus conserves the energy and material required for rapid growth and maintenance. Support for this idea comes from in silico experiments using the PIM applied to a model metabolic pathway A --> B --> C. The metabolites A, B, and C are small molecules that diffuse freely in a cytosol crowded with macromolecules, whereas the large enzyme molecules, E1 and E2, tend to remain in the vicinity of their point of release. Modeling E1 as a source of B from A, and E2 as a sink for B, numerical experiments suggest that the steady state concentration of B in the cytosol increases approximately in proportion to the square of the distance of the E1 and E2 separation. A further model prediction is that the steady state concentration of B is influenced by the geometric effects of the spatial location and orientation of E1 relative to E2. These results suggest that: (i) gene clustering reduces the energy and material costs of enzyme reactions linked by metabolic intermediates; (ii) gene clusters near ori, the origin of replication, utilize the geometric effect to conserve free energy by further reducing the steady state concentration of the intermediate; (iii) gene organization on a chromosome influences the organism's capacity to accelerate into steady state growth and is, in turn, influenced by the abundance and frequency of access to nutrients.