Osmotic effects of protein polymerization: Analysis of volume changes in sickle cell anemia red cells following deoxy-hemoglobin S polymerization

Summary Polymerization-depolymerization of proteins within cells and subcellular organelles may have powerful osmotic effects. As a model to study these we analyzed the predicted volume changes following hemoglobin (Hb) S polymerization in sickle cell anemia (SS) red cells with different initial volumes. The theoretical analysis predicted that dehydrated SS red cells may sustain large polymerization-induced volume shifts whose direction would depend on whether or not small solutes were excluded from polymer-associated water. Experiments with SS cells from promptly fractionated venous blood showed oxygenation-induced swelling, maximal in the densest cells, in support of nonexclusion models. The predicted extent of cell dehydration on polymerization was strongly influenced by factors such as the dilution of residual soluble Hb and the increased osmotic contribution of Hb in cells dehydrated by salt loss, largely overlooked in the past. The osmotic effects of polymer formation may thus play an important part in microcirculatory infarction by dense SS cells, as they become even denser and stiffer during deoxygenation in the capillaries.     

Feasibility,Acceptability, and Preliminary Efficacy of an Intensive Clinic-Based Intervention for Children With Poorly Controlled Type 1 Diabetes

ObjectiveTo evaluate the feasibility, acceptability, and preliminary efficacy of a team-based intervention for youth with type 1 diabetes (T1D) with suboptimal glycemia, as detected based on the measurement of hemoglobin A1C (HbA1C).MethodsForty participants with T1D for >1 year and an HbA1C level of ≥9.5% (80 mmol/mol) enrolled for a multidisciplinary intervention that included pediatric endocrinologists, pediatric psychologists, and a certified diabetes care and education specialist (CDCES). The CDCES-integrated medical management, while reinforcing physical, emotional, and behavioral health, connected with families to set and monitor goals and reviewed medication adjustments. The feasibility was assessed based on enrollment targets; acceptability based on retention rates; and preliminary efficacy based on changes in HbA1C levels, quality of life, diabetes-related strengths and resilience, hospital admissions, emergency room visits, and missed school days.ResultsOf 43 patients and families approached, 40 agreed to participate, 36 completed the 4-month intervention, and 31 completed full 8 months of follow-up data collection. The CDCES coach averaged 6.8 contacts per participant during the 8-month study period. The HbA1C level reduced significantly from baseline to 4 months (12.1% ± 1.6% to 11.0% ± 1.9%, P = .001) and was sustained at 8 months (10.7% ± 1.9%, P < .001). The participants reported significant increases in diabetes-specific quality of life (P < .05) and diabetes-related strength and resilience (P = .003). The missed school days reduced from 7.23 ± 7.5 days to 1.55 ± 1.9 days (P < .001), and the diabetes-related hospitalizations decreased from 0.4 ± 0.6 to 0.1 ± 0.3 (P = .009).ConclusionPreliminary data suggest that a multidisciplinary intervention leveraging a team-based approach with a physician, psychologist, and CDCES can support improvements in glycemic control and psychosocial outcomes among youth with T1D with an HbA1C level above the target.     

Outreach Method Predicts Patient Re-engagement in Diabetes Care During Sustained Care Disruption

ObjectiveDuring the COVID-19 pandemic, visits for diabetes care were abruptly canceled without predefined procedures to re-engage patients. This study was designed to determine how outreach influences patients to maintain diabetes care and identify factors that might impact the intervention’s efficacy.MethodsA diabetes nursing team attempted outreach for patients who had a canceled appointment for diabetes between March 16, 2020, and June 19, 2020. Outreach status was defined as reached, message left, or no contact. Outcomes were defined as follows: (1) booking and (2) keeping a follow-up appointment.ResultsSeven hundred eighty-seven patients were included (384 [49%] were reached, 152 (19%) were left a message, and 251 (32%) had no contact). Reached patients were more likely to book [odds ratio (OR) = 2.43, P < .001] and keep an appointment (OR = 2.39, P < .001) than no-contact patients. Leaving a message did not increase the odds of booking (OR = 1.05, P = .84) or keeping (OR = 1.17, P = .568) an appointment compared with no contact. Older age was a significant predictor of booking an appointment (OR = 1.014 for each year of age, P = .037). Patients on insulin were more likely to keep their appointment (OR = 1.70, P = .008). Patients with a higher hemoglobin A1C level were less likely to keep their appointment (OR = 0.87 for each 1.0% increase in the hemoglobin A1C level, P = .011).ConclusionThese findings suggest that to optimize re-engagement during care disruption, 1-way communication is no better than no contact and that 2-way communication increases the likelihood that patients will maintain access to care. In addition, although higher-risk patients (eg, patients with older age or those on insulin) may be more incentivized to stay engaged, targeted outreach is needed for those with chronically poor glycemic control.     

Enzyme polymorphism in Malayan rats of the Subgenus Rattus

Electrophoretic variation in nine red cell proteins was analysed in 256 specimens belonging to six species of Malayan Rattus (including one with two subspecies) of the subgenus Rattus. The average proportion of loci heterozygous per individual for the taxa analysed is 0.04. With the exception of Rattus rattus diardii, R. tiomanicus tiomanicus and R. t. jalorensis, individuals of the other species could be identified by specific electrophoretic phenotypes of one or more of the markers analysed. Relationships among the species studied were elucidated by the classical and phenetic approaches employing electrophoretic characters. The results obtained by the two approaches were similar in most respects and they corresponded better with results based on morphological characters than those based on cytological characters.     

Inter- and Intrasyngenic Variations of the Hemoglobin Components in Paramecium caudatum

ABSTRACT The ciliated protozoan Paramecium contains hemoglobin in heterogeneous monomeric forms. In particular, Paramecium caudatum is characterized by the presence of a major component called Hb10 and a basic component named bHb. We found that in P. caudatum both of these hemoglobin components show some variation according to stock. The types and distributions of these hemoglobin components were examined on 16 stocks in five different syngens and one stock in an unidentified syngen using high performance liquid chromatography. The results indicate that in a variety of stocks the major component, Hb10, was divided into three types, A, B or A + B, and that the basic hemoglobin component was composed of a combination of two or three variants out of four possible, i.e. bHb 1, bHb 2, bHb 3 and bHb 4. Neither the Hb10 types nor the bHb variants, however, could be used to distinguish syngen in P. caudatum , since all of the Hb10 types and bHb variants were widely distributed over syngens and identical profiles appeared to some stocks in different syngens.     

Automated Insulin Delivery Systems as a Treatment for Type 2 Diabetes Mellitus: A Review

ObjectiveApproximately 6.3% of the worldwide population has type 2 diabetes mellitus (T2DM), and the number of people requiring insulin is increasing. Automated insulin delivery (AID) systems integrate continuous subcutaneous insulin infusion and continuous glucose monitoring with a predictive control algorithm to provide more physiologic glycemic control. Personalized glycemic targets are recommended in T2DM owing to the heterogeneity of the disease. Based on the success of hybrid closed-loop systems in improving glycemic control and safety in type 1 diabetes mellitus, there has been further interest in the use of these systems in people with T2DM.MethodsWe performed a review of AID systems with a focus on the T2DM population.ResultsIn 5 randomized controlled trials, AID systems improve time in range and reduce glycemic variability, without increasing insulin requirements or the risk of hypoglycemia.ConclusionAID systems in T2DM are safe and effective in hospitalized and closely monitored settings. Home studies of longer duration are required to assess for long-term benefit and identify target populations of benefit.     

Albuminuria,Disease Duration,and Glycated Hemoglobin Are Related With Bone Mineral Density in Type 1 Diabetes: A Cross-sectional Study

ObjectiveStudies have found a significant decrease in bone mineral density (BMD) in individuals with type 1 diabetes (T1D) compared to healthy controls. Factors associated with this phenomenon have yet to be defined; therefore, this study aimed to explore the association of glycated hemoglobin (HbA1c), disease duration, albuminuria, and glomerular filtration rate with BMD in adults with T1D.MethodsA cross-sectional study was carried out in tertiary care center. BMD analysis was performed by dual x-ray absorptiometry. Linear models were constructed considering variables associated with BMD. Approval from the ethics committees and informed consent were obtained.ResultsWe included 128 participants, of whom 59% were women, and 16% had menopause. The median age was 33 (26-42) years. The average age of diabetes diagnosis was 15.3 ± 6.3 years, and the median disease duration was 19.5 (12-27) years. In the adjusted analysis, higher albuminuria (P < .01) and disease duration (P < .05) were associated with a lower BMD in the femoral neck and total hip, independently of age, sex, and body mass index (BMI). Higher HbA1c (P < .01) was associated with a lower spine BMD after adjustment for age, sex, and BMI.ConclusionStudied factors specific to T1D, including albuminuria, disease duration, and HbA1c have an association with BMD regardless of BMI, age, and sex.     

A Clinical Prediction Model to Distinguish Maturity-Onset Diabetes of the Young From Type 1 and Type 2 Diabetes in the Chinese Population

ObjectiveGenetic detection for the diagnosis of maturity-onset diabetes of the young (MODY) in China has low sensitivity and specificity. Better gene detection is urgently needed to distinguish testing subjects. We proposed to use numerous and weighted clinical traits as key indicators for reasonable genetic testing to predict the probability of MODY in the Chinese population.MethodsWe created a prediction model based on data from 306 patients, including 140 patients with MODY, 84 patients with type 1 diabetes (T1D), and 82 patients with type 2 diabetes (T2D). This model was evaluated using receiver operating characteristic curves.ResultsCompared with patients with T1D, patients with MODY had higher C-peptide levels and negative antibodies, and most patients with MODY had a family history of diabetes. Different from T2D, MODY was characterized by lower body mass index and younger diagnostic age. A clinical prediction model was established to define the comprehensive probability of MODY by a weighted consolidation of the most distinguishing features, and the model showed excellent discrimination (areas under the curve of 0.916 in MODY vs T1D and 0.942 in MODY vs T2D). Further, high-sensitivity C-reactive protein, glycated hemoglobin A1c, 2-h postprandial glucose, and triglyceride were used as indicators for glucokinase-MODY, while triglyceride, high-sensitivity C-reactive protein, and hepatocellular adenoma were used as indicators for hepatocyte nuclear factor 1-α MODY.ConclusionWe developed a practical prediction model that could predict the probability of MODY and provide information to identify glucokinase-MODY and hepatocyte nuclear factor 1-α MODY. These results provide an advanced and more reasonable process to identify the most appropriate patients for genetic testing.     

Prosimian hemoglobins: IV. The structural difference responsible for the hemoglobin phenotype of Lemur catta

The ring-tailed lemur, Lemur catta, shows a two-component hemoglobin phenotype after alkaline electrophoresis. A difference in the amino acid sequence of the isolated α-globins was observed at position 15 (α I-Gly, α II-Lys) and can account for the electrophoretic pattern of two hemoglobin components. Only one other amino acid difference was found in the sequence of the two globin chains: a neutral substitution occurs at position 53 (α I-Gly, α II-Ala). The complete primary structures of the duplicated α-globin chains of Lemur catta are presented.