Improved polyacrylamide gel electrophoresis with different amino acids as the trailing constituent

Using a polyacrylamide disc gel electrophoretic system similar to that described by J. T. Clarke (1964, Ann. N. Y. Acad. Sci.121, 428–436), we have achieved an improved separation of hemoglobins from Rana catesbeiana tadpoles by substituting one of several amino acids in the place of glycine in the electrode chamber buffer. The relative migrations (R_f) and degree of separation of these similar hemoglobins are proportional to the pK′ of the α-amino group of the amino acid used in the buffer. Specifically, for these proteins, log (R_f × 100) was found to be directly proportional to the pK′₂ of the amino acid divided by the volume conductivity (specific conductance) of the electrode chamber buffer. For example, improved separation of these hemoglobins in short electrophoretic times can be achieved, at low cost, by using dl-alanine instead of glycine in the buffer. Improved separation of other proteins which migrate at basic pH might be achieved by a similar approach.     

Increase in the Number of Pediatric New-Onset Diabetes and Diabetic Ketoacidosis Cases During the COVID-19 Pandemic

ObjectiveInfection with SARS-CoV-2 induces a proinflammatory state that causes hyperglycemia and may precipitate diabetic ketoacidosis (DKA) in patients with known or new-onset diabetes. We examined the trends in new-onset diabetes and DKA prior to and following the onset of the COVID-19 pandemic.MethodsThis single-center retrospective observational study included pediatric patients (aged 0 to <18 years) hospitalized with new-onset type 1 diabetes or type 2 diabetes (T2D) before (March 1, 2018, to February 29, 2020) and after (March 1, 2020 to December 31, 2020) the pandemic onset. Demographic, anthropometrics, laboratory and clinical data, and outcomes were obtained.ResultsAmong 615 children admitted with new-onset diabetes during the entire study period, 401 were admitted before the pandemic onset, and 214 were admitted after the pandemic onset. Children admitted with new-onset diabetes in the postpandemic period were significantly more likely to present with DKA (odds ratio, 1.76; 95% confidence interval, 1.24-2.52) than in the prepandemic phase. Children with DKA after the pandemic onset had higher lengths of hospitalization and were significantly more likely to experience severe DKA (odds ratio, 2.17; 95% confidence interval, 1.34-3.52). A higher proportion of children with DKA admitted to the pediatric intensive care unit required oxygen support after the pandemic onset than before the pandemic onset (8.85% vs 1.92%). Most cases of T2D with DKA occurred following the onset of the pandemic (62.5%).ConclusionA significant increase in T2D cases occurred following the onset of the COVID-19 pandemic with a greater risk of DKA and severe ketoacidosis. Racial disparity was evident with a higher proportion of Black and American Indian children presenting with ketoacidosis following the pandemic onset.     

The 2/2 hemoglobin from the cyanobacterium Synechococcus sp. PCC 7002 with covalently attached heme: Comparison of X‐ray and NMR structures

The X‐ray structures of the hemoglobin from Synechococcus sp. PCC 7002 (GlbN) were solved in the ferric bis‐histidine (1.44 Å resolution) and cyanide‐bound (2.25 Å resolution) states with covalently attached heme. The two structures illustrate the conformational changes and cavity opening caused by exogenous ligand binding. They also reveal an unusually distorted heme, ruffled as in c cytochromes. Comparison to the solution structure demonstrates the influence of crystal packing on several structural elements, whereas comparison to GlbN from Synechocystis sp. PCC 6803 shows subtle differences in heme geometries and environment. The new structures will be instrumental in elucidating GlbN reactivity. Proteins 2014; 82:528–534. © 2013 Wiley Periodicals, Inc.     

A Pilot Study of Youth With Type 1 Diabetes Initiating Use of a Hybrid Closed-Loop System While Receiving a Behavioral Economics Intervention

ObjectiveMany youth do not use the hybrid closed-loop system for type 1 diabetes effectively. This study evaluated the impact of financial incentives for diabetes-related tasks on use of the 670G hybrid closed-loop system and on glycemia.MethodsAt auto mode initiation and for 16 weeks thereafter, participants received a flat rate for wearing and calibrating the sensor ($1/day), administering at least 3 mealtime insulin boluses per day ($1/day), and uploading ($5/week). Weekly bonuses were given for maintaining at least 70% of the time in auto mode, which were increased for persistent auto mode use from $3/week to a maximum of $13/week. If a participant failed to maintain auto mode for a week, the rewards were reset to baseline. Data from 17 participants aged 15.9 years ± 2.5 years (baseline hemoglobin A1c [HbA1c] 8.6% ± 1.1%) were collected at 6, 12, and 16 weeks. The reinforcers were withdrawn at 16 weeks, with a follow-up assessment at 24 weeks.ResultsWith reinforcers, the participants administered an average of at least 3 mealtime insulin boluses per day and wore the sensor over 70% of the time. However, auto mode use waned. HbA1c levels decreased by 0.5% after 6 weeks, and this improvement was maintained at 12 and 16 weeks (P < .05). Upon withdrawal of reinforcers, HbA1c levels increased back to baseline at 24 weeks.ConclusionCompensation for diabetes-related tasks was associated with lower HbA1c levels, consistent administration of mealtime insulin boluses, and sustained sensor use. These results support the potential of financial rewards for improving outcomes in youth with type 1 diabetes.     

Is Obesity or Adiposity-Based Chronic Disease Curable: The Set Point Theory,the Environment,and Second-Generation Medications

Adiposity-based chronic disease (ABCD) requires life-long treatment and follow up. Obesity protects obesity through altered regulation of caloric intake and set point mechanisms, which help maintain a high equilibrium body weight. Lifestyle interventions and obesity medications do not permanently alter the set point, which often makes weight loss achieved using lifestyle changes short-lived and operates to drive weight regain once medications are discontinued. Bariatric surgery procedures can alter appetite and lower the “set point” for the equilibrium body weight via unknown mechanisms. However, few patients attain an ideal body weight following surgery, many regain weight, and all require long-term follow up for the disease. The excess adiposity associated with ABCD gives rise to complications that impair health and confer morbidity and mortality; however, the genetic risks and potential interactions between genes and the environment that give rise to complications cannot be eliminated. The equilibrium body weight around which set point mechanisms operate can be modified by the environment, which underscores the importance of a less obesogenic environment for the prevention and treatment of ABCD on a population basis.Whether ABCD will eventually be curable will depend on a clear understanding of the molecular mechanisms that determine the set point regulation of body weight and the ability to permanently modulate the set point to oscillate around a lean body mass. However, the conceptualization of ABCD as a chronic disease does present us with opportunities for primary, secondary, and tertiary prevention to avert disease progression. For tertiary care, the advent of new, more effective second-generation obesity medications will allow clinicians to treat to target via active management of body weight into a target range that will ameliorate specific complications.     

Application of high-precision isotope ratio monitoring mass spectrometry to identify the biosynthetic origins of proteins

Isotope ratio monitoring (IRM) mass spectrometry was used to measure the relative abundance of stable isotopes in several samples of adult human hemoglobin expressed in E. coli, yeast, and human blood. The results showed significant differences in the distribution of (15)N and (13)C isotopes among hemoglobin samples produced in these organisms. This indicates that IRM mass spectrometry can be used in forensic protein chemistry to identify the origin of protein expression.     

The effects of nickel oxide nanoparticles on structural changes,heme degradation,aggregation of hemoglobin and expression of apoptotic genes in lymphocytes

Abstract

Nickel oxide nanoparticles (NiO NPs) have received great interests in medical and biotechnological applications. However, their adverse impacts against biological systems have not been well-explored. Herein, the influence of NiO NPs on structural changes, heme degradation and aggregation of hemoglobin (Hb) was evaluated by UV-visible (Vis) spectroscopy, circular dichroism (CD) spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), and molecular modeling investigations. Also, the morphological changes and expression of Bax/Bcl-2 mRNA in human lymphocyte cell exposed to NiO NPs were assayed by DAPI staining and quantitative real-time PCR (qPCR), respectively. The UV-Vis study depicted that NiO NPs resulted in the displacement of aromatic residues and heme groups and production of the pro-aggregatory species. Intrinsic and Thioflavin T (ThT) fluorescence studies revealed that NiO NPs resulted in heme degradation and amorphous aggregation of Hb, respectively, which the latter result was also confirmed by TEM study. Moreover, far UV-CD study depicted that NiO NPs lead to substantial secondary structural changes of Hb. Furthermore, near UV-CD displayed that NiO NPs cause quaternary conformational changes of Hb as well as heme displacement. Molecular modelling study also approved that NiO NPs resulted in structural alterations of Hb and heme deformation. Moreover, morphological and genotoxicity assays revealed that the DNA fragmentation and expression ratio of Bax/Bcl-2 mRNA increased in lymphocyte cells treated with NiO NPs for 24?hr. In conclusion, this study indicates that NiO NPs may affect the biological media and their applications should be limited.

Communicated by Ramaswamy H. Sarma     

A comparison of the periparturient rise in fecal egg counts of exotic and domestic ewes

Ewes of three exotic breeds (Florida Native, Barbados Blackbelly and St. Croix) showed no periparturient rise in fecal egg counts (PPR) when housed from late fall through lambing and weaning. Domestic breed ewes (Rambouillet and Finn-Dorset × Rambouillet) showed a pronounced PPR 6–7 weeks post-lambing while St. Croix × domestic ewes showed an intermediate PPR under similar conditions. There was no PPR in non-lambing ewes.In a second experiment, breed differences in the PPR were not as pronounced when ewes were allowed to graze a contaminated pasture after lambing. Florida Native, St. Croix and $\text{3}\text{4}$ St. Croix × $\text{1}\text{4}$ domestic showed lower PPRs than the remaining breeds (Barbados Blackbelly, F₁ hybrids of exotic and domestic breeds and domestic ewes), but the magnitude of the PPR was generally small in all breeds. No relationship was observed between hemoglobin genotype and PPR in either experiment.It was concluded that a low or absent PPR is an important manifestation of breed resistance in exotic ewes and that this may be useful as a marker for breeding parasite-resistant sheep.     

Association Between a Low-Carbohydrate Diet,Glycemic Control,and Quality of Life in Australian Adults Living With Type 1 Diabetes: A Pilot Study

ObjectiveTo examine if there is an association between a low-carbohydrate diet (LCD), glycemic control, and quality of life (QoL) in Australian adults with type 1 diabetes.MethodsThis single-group, pre-post, mixed methods (quantitative and qualitative) study was conducted in an outpatient tertiary hospital. Eligible participants were those aged ≥18 years, with type 1 diabetes for ≥1 year, and using multiple daily insulin injections. Participants followed a 12-week individualized LCD (<100 g/d). Daily glucose levels were monitored using a continuous glucose monitor. Glycated hemoglobin (HbA1c) and QoL were measured preintervention and postintervention. A post-hoc exploratory regression analysis determined whether changes in carbohydrate intake was associated with changes in HbA1c and QoL. Qualitative data collected postintervention explored participants’ perceptions relating to a LCD, glycemic control, and QoL.ResultsParticipants (n = 22) completed the 12-week LCD intervention. An LCD provided a statistically, significant improvement in HbA1c 0.83% (95% CI 0.32%-1.33%), P = .003 but did not impact QoL: estimated change 1.14 units (95% CI: ?5.34 to 7.61); P = .72. The post-hoc exploratory regression analysis showed that participants with poorer baseline glycemic control were more likely to respond to an LCD resulting in significant reductions in HbA1c. Participant perceptions relating to the study variables were mixed.ConclusionsAn LCD (<100 g/d) is a potentially effective and safe strategy to improve glycemic control without negatively effecting QoL in Australian adults with type 1 diabetes.