Expression and transcriptional activity of alternative splice variants of Mitf exon 6

Heme proteins––hemoglobin and myoglobin possess esterase activities. Studies with purified hemoglobin from normal individuals and diabetic patients revealed that the esterase activity as measured from hydrolysis of p-nitrophenyl acetate (p-NPA) was higher in diabetic condition and increased progressively with extent of the disease. HbA_1c, the major glycated hemoglobin, which increases proportionately with blood glucose level in diabetes mellitus, exhibited more esterase activity than the non-glycated hemoglobin fraction, HbA₀, as demonstrated spectrophotometrically as well as by activity staining. Glycation influenced esterase activity of hemoglobin by increasing the affinity for the substrate and the rate of the reaction. Both HbA₀ and HbA_1c-mediated catalysis of p-NPA hydrolysis was pH-dependent. Esterase activity of in vitro-glycated myoglobin (GMb) was also higher than that of its non-glycated analog (Mb). The amplified esterase activities of hemoglobin and myoglobin might be associated with glycation-induced structural modifications of the proteins.     

Heterogeneity of hemoglobin A1d: assessment and partial characterization of two new minor hemoglobins, A1d3a and A1d3b, increased in uremic and diabetic patients, respectively

We have separated and quantified two new minor hemoglobins named HbA_1d3a and HbA_1d3b. The level of HbA_1d3a was significantly higher in uremic than in non-uremic patients (3.00 ± 0.50% vs. 1.28 ± 0.26% of total hemoglobin). It correlated well with carbamylated hemoglobin (r=0.80, n=81, p<0.002) and with plasma urea concentration (r=0.78, n=81, p<0.002). These data and the electrospray ionization mass spectrometric analysis provide strong evidence that HbA_1d3a is an α-chain modified by carbamylation. The HbA_1d3b level in the diabetic patients was found to be 1.6-fold that in non-diabetic subjects (3.00 ± 0.49 vs. 1.90 ± 0.33). This was attributed to HbA_1d3 modified by glycation. Indeed HbA_1d3b correlated significantly with HbA_1c (r=0.71, p<0.002) and with serum glucose level (r=0.62, p<0.002). These two new minor hemoglobins may serve as complements for the objective assessment of averagd long-term uremia and glycemia in uremic and diabetic patients.     

Assessment of AACE/ACE Recommendations for Initial Dual Antihyperglycemic Therapy Using the Fixed-Dose Combination of Sitagliptin and Metformin Versus Metformin

ObjectiveThe American Association of Clinical Endocrinologists and American College of Endocrinology (AACE/ACE) diabetes algorithm recommends a stratified approach to initial therapy to achieve a glycated hemoglobin (HbA_1c) goal of <6.5% in patients with type 2 diabetes mellitus (T2DM) who have inadequate glycemic control. Data from a double-blind study in drug-naïve T2DM patients comparing initial monotherapy with metformin (MET) with initial dual therapy with a fixed-dose combination of sitagliptin and MET (SITA/MET FDC) was used to determine AACE/ACE HbA_1c goal attainment in these treatment groups.MethodsA total of 1,250 patients (mean baseline HbA_1c = 9.9%) were randomized 1:1 to SITA/MET FDC 50/500 mg twice daily (b.i.d.) or MET 500 mg b.i.d. for 18 weeks. SITA/MET FDC and MET were uptitrated over 4 weeks to 50/1,000 mg b.i.d. and 1,000 mg b.i.d., respectively.ResultsAt week 18, a higher percentage of patients receiving SITA/MET FDC had HbA_1c levels <6.5% and <7% than those receiving MET alone within each of the 3 AACE/ACE HbA_1c categories (6.5-7.5%, >7.5-9.0%, and >9.0%). Of patients with a baseline HbA_1c >7.5-9.0% who initiated SITA/MET FDC, 48.6% achieved an HbA_1c <6.5% at week 18 compared with 23.1% of patients who initiated MET monotherapy (P<.001). In patients with a baseline HbA >9.0%, 24.0% on SITA/MET FDC achieved an HbA_1c <6.5% compared with 12.8% on MET alone (P<.001).ConclusionIn T2DM patients with a baseline HbA_1c >7.5-9.0%, substantially more achieved the HbA_1c goal of <6.5% with initial dual therapy (SITA/MET FDC) than with initial monotherapy (MET), which is in agreement with the AACE/ACE diabetes algorithm.(Endocr Pract. 2013;19:751-757)     

Relationship between glycated hemoglobin and glucose concentrations in the adult Galician population: selection of optimal glycated hemoglobin cut-off points as a diagnostic tool of diabetes mellitus

Aims/hypothesisTo analyze the relationship between glucose and glycated hemoglobin (HbA_1c) in the adult Galician population, evaluate the use of HbA_1c for the screening and diagnosis of diabetes, and calculate the diagnostic threshold required for this purpose.MethodsWe analyzed data on 2848 subjects (aged 18–85 years) drawn from a study undertaken in 2004 to assess the prevalence of diabetes in Galicia. For study purposes, diabetes was defined using the criteria recommended in 2002. Participants were classified into four glucose-based groups. The relationship between glucose and HbA_1c was described using linear regression models, generalized additive models and Spearman's correlation. Diagnostic capacity was assessed, and optimal HbA_1c cut-off points were calculated as a diabetes marker using the receiver operating characteristic curve.ResultsPrevalence of pre-diabetes, unknown diabetes and known diabetes was 20.86, 3.37 and 4.39%, respectively. The correlations between HbA_1c and fasting glucose were higher than those obtained for HbA_1c and glycemia at 2 h of the oral glucose overload (0.344 and 0.270, respectively). Taking glucose levels as the gold standard, a greater discriminatory capacity was obtained for HbA_1c (area under de cruve: 0.839, 95% confidence intervals: 0.788–0.890). Based on the study criteria, the optimal minimum and maximum HbA_1c values were 5.9% and 6.7%, respectively.Conclusions/interpretationHbA_1c did not prove superior to glycemia for diagnosis of diabetes in the adult Galician population, and cannot therefore be used to replace the oral glucose tolerance test for screening and diagnosis purposes. Indeed, determination of glucose is essential to verify the diagnosis in the majority of cases.     

Greater Combined Reductions in Hba1C ≥1.0% and Weight ≥5.0% with Semaglutide Versus Comparators in type 2 Diabetes

Objective: Semaglutide is a glucagon-like peptide 1 (GLP-1) analog for the once-weekly treatment of type 2 diabetes (T2D). In the global SUSTAIN clinical trial program, semaglutide demonstrated superior glycated hemoglobin (HbA_1c) and body weight reductions versus comparators. This post hoc analysis compared the proportion of patients achieving combined reductions in glycemia and body weight versus comparators.Methods: A total of 5,119 subjects with T2D in the phase 3 SUSTAIN 1 through 5 and 7 trials, from 33 countries, were included in this post hoc analysis. Subjects received subcutaneous semaglutide 0.5 or 1.0 mg, placebo or active comparator (sitagliptin 100 mg, exenatide extended release 2.0 mg, insulin glargine, dulaglutide 0.75 or 1.5 mg). The main endpoint was a composite of ≥1.0% HbA_1c reduction and ≥5.0% weight loss at end of treatment.Results: Significantly greater proportions of subjects achieved the composite endpoint with semaglutide 0.5 (25 to 38%) and 1.0 mg (38 to 59%) versus comparators (2 to 23%). More subjects treated with semaglutide versus comparators achieved ≥1.0% HbA_1c reductions (58 to 77% and 75 to 83% for semaglutide 0.5 and 1.0 mg versus 12 to 68%) and ≥5.0% weight loss (37 to 46%, 45 to 66% versus 4 to 30%). Proportions of subjects achieving targets were significantly higher with semaglutide 1.0 versus 0.5 mg in four of five trials. Semaglutide was well tolerated, with a safety profile similar to other GLP-1 receptor agonists.Conclusion: Significantly more subjects achieved both ≥1.0% HbA_1c reduction and ≥5.0% weight loss with once-weekly subcutaneous semaglutide treatment versus comparators in the SUSTAIN trials. A dose-dependent effect was observed with semaglutide.Abbreviations: AE = adverse event; CV = cardiovascular; ER = extended release; GLP-1 = glucagon-like peptide 1; GLP-1 RA = glucagon-like peptide 1 receptor agonist; HbA_1c = glycated hemoglobin; OAD = oral antidiabetic drug; sc = subcutaneous; T2D = type 2 diabetes     

Independent Association of HbA1c and Incident Cardiovascular Disease in People Without Diabetes

Recent studies have reported no association between elevated glycated hemoglobin (HbA_1c) and incident cardiovascular disease (CVD) among women without diabetes. This study describes associations between HbA_1c and new onset CVD in a representative adult population cohort. Assessment of participants in The North West Adelaide Health Study (NWAHS), a population study of randomly selected adults (age ≥18 years, n = 4,060), included measurement of height, weight, blood pressure, fasting lipids, glucose, and HbA_1c. A self‐completed questionnaire assessed doctor‐diagnosed diabetes, CVD and stroke, smoking status, and demographics. The cohort was followed for an average 3.5 years. Of the 2,913 adults free of diabetes at baseline and follow‐up, 94 (3.5%) reported new onset coronary heart disease (CHD) and/or stroke. Compared with those with an HbA_1c ≤5.0%, risk of new onset CVD was increased in those with HbA_1c 5.4–5.6% (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.4, 4.6), and ≥5.7% (OR 1.9, 95% CI 1.1, 3.4), after adjustment for other risk factors. The association was stronger in women than men (P = 0.03), and attenuated to only a small degree by addition of impaired fasting glucose (IFG), hypertension, hypercholesterolemia, BMI, waist circumference, or smoking to the model. Elevated HbA_1c is related to new onset CVD over a relatively short follow‐up period in both men and women without diabetes and who do not develop diabetes, after adjustment for other major risk factors. Unlike previous studies, this relationship was not substantially attenuated by other traditional risk factors.     

Falsely Decreased Hba1c in A Type 2 Diabetic Patient Treated with Dapsone

ObjectiveTo discuss a case of a falsely low hemoglobin A_1c (HbA_1c) in a transplant patient treated with dapsone and its implications. HbA_1c is widely used as a measure of glycemic control in diabetic patients. With the increasing transplant population, it is important to be mindful of medications used in this population that can affect HbA_1c and to use other measures of glycemic control to guide treatment decisions.MethodsWe present details of the case and review the relevant literature.ResultsA 61-year-old patient received a liver transplant in 2012 and subsequently was noted to have a falling HbA_1c despite evidence of hyperglycemia based on fingerstick glucose and fructosamine measurements. Review of the medical records revealed that the discordance between HbA_1c and fingerstick glucose levels developed after initiation of dapsone therapy. Dapsone may lead to a falsely low HbA_1c via several mechanisms. Upon cessation of dapsone therapy, the patient’s HbA_1c returned to pre-dapsone levels.ConclusionIt is important to be aware of medications commonly used in transplant patients that may lead to a falsely low HbA_1c level so that incorrect treatment decisions are not made. Fructosamine correlates with HbA_1c and can be used as a measure of glycemic control in transplant patients when HbA_1c cannot be used. (Endocr Pract. 2014;20:e229-e232)     

Does polyamine oxidase activity influence the oxidative metabolism of children who suffer of diabetes mellitus?

Diabetes mellitus is a metabolic disease characterized by inadequate secretion of insulin. Polyamine oxidase (PAO), a FAD-containing enzyme is involved in the biodegradation of Sp and Spd, catalyzing the oxidative deamination of Sp and Spd, resulting in production of amonia (NH₃), corresponding amino aldehydes and H₂O₂. Malondialdehyde (MDA) and acrolein (CH2=CHCHO), potentially toxic agents, which induce oxidative stress in mammalian cells, are then spontaneously formed from aminoaldehydes. The main signs of oxidative stress in diabetic children were the values of HbA1c and MDA levels. Polyamines have an insulin-like action. Antiglycation property of spermine and spermidine has been recently confirmed. There are no data in the literature about plasma polyamine oxidase (PAO) activities in children with type 1 diabetes. The idea of this study was to evaluate the polyamine metabolism through the estimation of polyamine oxidase activity. We have study children with newly diagnosed type 1 diabetes mellitus (n = 35, age group of 5–16 years, as well as age-matched healthy control subjects (n = 25). The biochemical investigations were done on diabetic children who have the pathological values of glucose (9.11–17.33 mmol/l) and glycosylated Hb (7.57–14.49% HbA_1c). The children in the control group have referent values of glucose and glycated hemoglobin (4.11-5.84 mmol/L and HbA_1c 4.22-6.81% of the total Hb. Glucose levels in blood plasma and glycosylated hemoglobin in erythrocythes hemolysates (HbA1c) were measured by using standard laboratory methods. PAO activity in venous blood plasma and the amount of malondialdehyde (MDA) were measured by the spectrophotometric methods. PAO activity, glycemia, HbA1c and MDA were significantly increased in diabetic children compared to the control subjects. PAO activity in children with type 1 diabetes mellitus was very high. The findings of higher blood HbA_1C and MDA levels confirm the presence of oxidant stress in children with type 1 diabetes mellitus and demonstrate that PAO activity may participate in these circumstances.     

Association between insomnia symptoms and hemoglobin A1c level in Japanese men

Background

The evidence for an association between insomnia symptoms and blood hemoglobin A_1c (HbA_1c) level has been limited and inconclusive. The aim of this study was to assess whether each symptom of initial, middle, and terminal insomnia influences HbA_1c level in Japanese men.

Methods

This cross-sectional study examined 1,022 male workers aged 22–69 years with no history of diabetes at a Japanese company''s annual health check-up in April 2010. High HbA_1c was defined as a blood level of HbA_1c ≥6.0%. Three types of insomnia symptoms (i.e., difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) from the previous month were assessed by 3 responses (i.e., lasting more than 2 weeks, sometimes, and seldom or never [reference group]).

Results

The overall prevalence of high HbA_1c was 5.2%. High HbA_1c was positively and linearly associated with both difficulty in maintaining sleep (P for trend  = .002) and early morning awakening (P for trend  = .007). More specifically, after adjusting for potential confounding factors, high HbA_1c was significantly associated with difficulty in maintaining sleep lasting more than 2 weeks (adjusted odds ratio, 6.79 [95% confidence interval, 1.86–24.85]) or sometimes (2.33 [1.19–4.55]). High HbA_1c was also significantly associated with early morning awakening lasting more than 2 weeks (3.96 [1.24–12.59]).

Conclusion

Insomnia symptoms, particularly difficulty in maintaining sleep and early morning awakening, were found to have a close association with high HbA_1c in a dose-response relationship.     

Efficacy and Safety of Linagliptin in Black/African American Patients with Type 2 Diabetes: A 6-Month,Randomized, Double-Blind,Placebo-Controlled Study

ObjectiveAlthough black/African American individuals are disproportionately affected by type 2 diabetes, there is scant clinical trial information available on antidiabetes therapies in this group. We compared linagliptin with placebo in black/African American adults who were treatment-naïve or receiving one oral antidiabetes drug.MethodsOf 226 patients randomized to 24 weeks’ linagliptin 5 mg/day or placebo, 208 had baseline and at least one on-treatment glycated hemoglobin (HbA_1c) measurement. Mean baseline HbA_1c was 8.6% in the linagliptin group (n = 98) and 8.68% in the placebo group (n = 110). The primary outcome was change in HbA_1c from baseline to week 24.ResultsBy week 24, mean HbA_1c changes were − 0.84% with linagliptin and − 0.25% with placebo (treatment difference, − 0.58%; P < .001), and more patients in the linagliptin group achieved HbA_1c < 7.0% (26.8% vs. 8.3%; P = .001) or an HbA_1c reduction ≥ 0.5% (54.1% vs. 30.0%; P < .001). Mean weight loss was − 1.1 kg in both groups. During the treatment period, 8 of 98 linagliptingroup patients and 17 of 110 placebo-group patients required rescue therapy (odds ratio, 0.5; P = .14). For postprandial glucose, values were available for few patients (11 placebo, 10 linagliptin), and thus the between-group difference was associated with wide confidence intervals (CIs) (difference, − 1.97 mg/dL; 95% CI, − 53.80 to 49.86; P = .94). In the overall study population, a similar proportion of patients in both groups had adverse events (58.5% vs. 61.7%); most events were mild or moderate and considered unrelated to study drug. Investigator-defined hypoglycemia was rare (3 linagliptin-group patients and 1 placebogroup patient), with no severe events (requiring external assistance).ConclusionThis study confirms that linagliptin is efficacious and well tolerated in black/African American patients with type 2 diabetes. (Endocr Pract. 2014;20: 412-420)     

Mass spectrometry based characterization of Hb Beckman variant in a falsely elevated HbA1c sample

Glycated hemoglobin (HbA_1c) is a ‘gold standard’ biomarker for assessing the glycemic index of an individual. HbA_1c is formed due to nonenzymatic glycosylation at N-terminal valine residue of the β-globin chain. Cation exchange based high performance liquid chromatography (CE–HPLC) is mostly used to quantify HbA_1c in blood sample. A few genetic variants of hemoglobin and post-translationally modified variants of hemoglobin interfere with CE–HPLC-based quantification, resulting in its false positive estimation. Using mass spectrometry, we analyzed a blood sample with abnormally high HbA_1c (52.1%) in the CE–HPLC method. The observed HbA_1c did not corroborate the blood glucose level of the patient. A mass spectrometry based bottom up proteomics approach, intact globin chain mass analysis, and chemical modification of the proteolytic peptides identified the presence of Hb Beckman, a genetic variant of hemoglobin, in the experimental sample. A similar surface area to charge ratio between HbA_1c and Hb Beckman might have resulted in the coelution of the variant with HbA_1c in CE–HPLC. Therefore, in the screening of diabetes mellitus through the estimation of HbA_1c, it is important to look for genetic variants of hemoglobin in samples that show abnormally high glycemic index, and HbA_1c must be estimated using an alternative method.     

血红蛋白A2现象发生机制的研究——“红细胞HbA2”为HbA2与HbA的结合产物

为了弄清血红蛋白A₂现象的发生机制,我们对“红细胞HbA₂”的化学组成进行了分析。“红细胞HbA₂”的双向电泳结果表明,它含有两种血红蛋白成分:一种相当于HbA,另一种很可能是溶血液HbA₂。其单向二次电泳结果也证明,它是由溶血液HbA₂和HbA所组成。结果初步说明,盘红细胞中HbA₂可能与HbA结合存在。两者可能有相互作用,也许这是产生血红蛋白A₂现象的原因。     

Diabetes Status and Race are Associated With Cardiovascular Risk Markers in Obese Adolescents

ObjectiveThe objective of this study was to evaluate differences in cardiovascular disease (CVD) risk markers in obese adolescents based on diabetes status and race in order to improve risk-reduction intervention strategies.MethodsThis was a retrospective, cross-sectional study of obese adolescents, age 10 to 21 years, who were evaluated at Children’s of Alabama between 2000 and 2012. Subjects were classified by glycated hemoglobin (HbA_1c) as having normoglycemia, prediabetes, or type 2 diabetes mellitus (T2DM).ResultsThere were a total of 491 African American (AA) or Caucasian American (CA) subjects. Body mass index was not different between HbA_1c and racial groups. Compared to subjects with normoglycemia or prediabetes, subjects with T2DM had higher levels of total cholesterol (TC) (178.6 ± 43.8 mg/dL vs. 161.5 ± 32.5 mg/dL vs. 162.4 ± 30.6 mg/dL; P < .0001) and low-density-lipoprotein cholesterol (107.4 ± 39.2 mg/dL vs. 97.0 ± 31.0 mg/dL vs. 97.5 ± 26.9 mg/dL; P = .0073). Compared with AA subjects, CA subjects had lower high-density-lipoprotein cholesterol (HDL-C) levels (40.4 ± 10.4 mg/dL vs. 44.3 ± 11.9 mg/dL; P = .0005) and higher non-HDL-C levels (129.6 ± 36.2 mg/dL vs. 122.5 ± 37.5 mg/dL; P = .0490). Of the characteristics studied, HbA_1c had the most significant positive association with dyslipidemia and was strongly correlated with both TC (β, 4.21; P < .0001) and non-HDL-C (β, 4.3; P < .0001).ConclusionObese adolescents with T2DM have more abnormal lipoprotein profiles than those with normoglycemia or prediabetes. Obese CA adolescents have more abnormal lipids than obese AA adolescents. HbA_1c was the characteristic most highly associated with abnormal lipoprotein profiles in our subjects. Our results show that CVD risk markers in obese adolescents vary by race and HbA_1c concentration. (Endocr Pract. 2015;21:165-173)     

Serum Trace Elements and Electrolytes Are Associated with Fasting Plasma Glucose and HbA<Subscript>1c</Subscript> in Postmenopausal Women with Type 2 Diabetes Mellitus

The primary aim of the research was to assess the level of trace elements and electrolytes in serum of postmenopausal diabetic women. Sixty-four postmenopausal women with type 2 diabetes mellitus (DM2) and 64 age- and body mass index-matched controls were examined. Serum trace elements were assessed using inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS). Fasting plasma glucose (FPG) and glycated hemoglobin (HbA_1c) levels were evaluated using Randox kits. The obtained data demonstrate that DM2 patients were characterized by 42 and 34 % higher FPG and HbA_1c levels, respectively (p < 0.001). The level of Cu and Se in diabetic postmenopausal women was increased by 10 and 15 % in comparison to the respective control values (p = 0.002 and <0.001). Serum Mn, Zn, and Ni concentrations were lower than the control ones by 32 % (p = 0.003), 8 % (p = 0.003), and 23 % (p = 0.046), respectively. FPG and HbA_1c levels directly correlated with serum Se (p < 0.001) and Cu (p = 0.014 and p = 0.028) concentrations and inversely related to Zn (p < 0.001) and Tl (p = 0.023 and p = 0.029) levels. Multiple regression analysis demonstrated a significant association between serum Zn and Se and FPG and HbA_1c levels. It is proposed that Zn and Se play an important role in DM2 pathogenesis. Further studies are required to assess the intimate mechanisms of the observed differences.     

Detection of HbA1c by boronate affinity immunoassay using bacterial magnetic particles

We have developed a boronate affinity immunoassay system using m-aminophenylboronic acid (mAPB) coupling to bacterial magnetic particles (BMPs). Homobifunctional crosslinker, Bis-(succcimidyl)suberate (BS3), was employed for preparation of mAPB-BMPs conjugates (mAPB-BMPs). Quantities of HbA_1c on mAPB-BMPs were evaluated based on luminescence from alkaline phosphatase-conjugated anti-Hb antibody (ALP–antibody) binding to HbA_1c on the BMP surface. The binding of HbA_1c to mAPB-BMPs occurred gradually and was almost completed within 10 mm. The coupling reaction is enhanced due to static electric interaction between the positive charges on HbA_1c and negative charges on BMPs. The amount of HbA_1c binding to mAPB-BMPs increased with increasing sodium chloride concentrations in the range of 0–100 mM. However, the amount of Hb binding to mAPB-BMPs also increased in high concentration of sodium chloride. The Hb binding to mAPB-BMPs was detached from mAPB-BMPs when Hb–mAPB-BMPs were washed with low salt buffer. This indicates that Hb is nonspecifically adsorbed onto the surface of mAPB-BMPs in high concentration of sodium chloride. These results suggest that selective separation of HbA_1c using mAPB-BMPs can be achieved with these conditions. A dose–response curve was obtained between luminescence intensity and HbA_1c concentration using a fully automated boronate affinity immunoassay. A linear relationship between luminescence intensity and HbA_1c concentration was obtained in the range of 10–10⁴ ng/ml.     

Effect of dietary substitution of groundnut oil on blood glucose, lipid profile, and redox status in streptozotocin-diabetic rats

The effect of groundnut oil on blood glucose, lipid profile, lipid peroxidation, and antioxidant status in streptozotocin-diabetic rats was investigated and compared with diabetic and drug-treated rats. Diabetes was induced in adult female Wistar rats by intraperitoneal administration of streptozotocin (40 mg/kg b-wt). Normal and diabetic rats were fed an oil-free diet containing 2 percent oil supplemented with groundnut oil (6g per 94g diet), to give 8 percent oil content, for 42 days. Diabetic rats had elevated levels of glucose (322.61 ± 9.49), glycosylated hemoglobin (HbA_1c), vitamin E, thiobarbituric acid reactive substances (TBARS), and lipid hydroperoxides (HP) and decreased levels of hemoglobin (Hb), vitamin C, and reduced glutathione (GSH). An increase in the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase and a decrease in hexokinase activity also were observed in the liver and kidney. When diabetic rats were fed groundnut oil, a significant reduction in glucose (244.04 ± 11.66), HbA_1c, TBARS, HP levels, and glucose-6-phosphatase and fructose-1,6-bisphosphatase activities and an elevation in Hb, vitamin E, GSH levels, and hexokinase activity were observed. Diabetic rats had elevated total cholesterol (TC), VLDL-cholesterol, LDL-cholesterol, and triglycerides (TG) and decreased HDL-cholesterol. Diabetic rats fed groundnut oil showed a small but significant reduction in TC, VLDL-C, LDL-C, and TG and an elevation in HDL-C. Groundnut oil consumption slightly but significantly decreases the blood glucose, HbA_1c, lipid peroxidation, and lipid profile and increases antioxidant levels in diabetic rats.     

Sputum Glucose and Glycemic Control in Cystic Fibrosis-Related Diabetes: A Cross-Sectional Study

Cystic fibrosis-related diabetes affects up to half of cystic fibrosis patients and is associated with increased mortality and more frequent pulmonary exacerbations. However, it is unclear to what degree good glycemic control might mitigate these risks and clinical outcomes have not previously been studied in relation to glucose from the lower airways, the site of infection and CF disease progression. We initially hypothesized that diabetic cystic fibrosis patients with glycosylated hemoglobin (HbA_1c) > 6.5% have worse pulmonary function, longer and more frequent exacerbations and also higher sputum glucose levels than patients with HbA_1c ≤ 6.5% or cystic fibrosis patients without diabetes. To test this, we analyzed spontaneously expectorated sputum samples from 88 cystic fibrosis patients. The median sputum glucose concentration was 0.70 mM (mean, 4.75 mM; range, 0-64.6 mM). Sputum glucose was not correlated with age, sex, body mass index, diabetes diagnosis, glycemic control, exacerbation frequency or length, or pulmonary function. Surprisingly, sputum glucose was highest in subjects with normal glucose tolerance, suggesting the dynamics of glycemic control, sputum glucose and pulmonary infections are more complex than previously thought. Two-year mean HbA_1c was positively correlated with the length of exacerbation admission (p < 0.01), and negatively correlated with measures of pulmonary function (p < 0.01). While total number of hospitalizations for exacerbations were not significantly different, subjects with an HbA_1c > 6.5% were hospitalized on average 6 days longer than those with HbA_1c ≤ 6.5% (p < 0.01). Current clinical care guidelines for cystic fibrosis-related diabetes target HbA_1c ≤ 7% to limit long-term microvascular damage, but more stringent glycemic control (HbA_1c ≤ 6.5%) may further reduce the short-term pulmonary complications.     

Two Treatment Approaches for Human Regular U-500 Insulin in Patients With Type 2 Diabetes not Achieving Adequate Glycemic Control on High-Dose U-100 Insulin Therapy With or Without Oral Agents: A Randomized,Titration-To-Target Clinical Trial

Objective: To compare the efficacy and safety of 2 dosing regimens for human regular U-500 insulin (U-500R, 500 units/mL) replacing high-dose U-100 insulins with or without oral antihyperglycemic drugs in patients with inadequately controlled type 2 diabetes (T2D).Methods: We conducted a 24-week, open-label, parallel trial in 325 patients (demographics [means]: age, 55.4 years; diabetes duration, 15.2 years; body mass index, 41.9 kg/m²; glycated hemoglobin [HbA_1c], 8.7%; U-100 insulin dose, 287.5 units administered in 5 injections/day [median; range, 2 to 10]). Patients were randomized to thrice-daily (TID, n = 162) or twice-daily (BID, n = 163) U-500R after a 4-week lead-in period. The primary outcome was HbA_1c change from baseline.Results: After 24 weeks, both treatments demonstrated significant HbA_1c reductions (TID, -1.12%; BID, -1.22%; both, P<.001) and clinical equivalence (difference, -0.10%; 95% confidence interval, -0.33 to 0.12%; noninferiority margin, 0.4%). Comparable increases in total daily U-500R dose (TID, 242.7 to 343.1 units; BID, 249.0 to 335.0 units) were observed. Incidence and rate of documented symptomatic hypoglycemia (≤70 mg/dL) were lower for TID versus BID (P = .003 and P = .02, respectively); severe hypoglycemia was similar between treatments. Weight gain was similar in both groups (TID, 5.4 kg; BID, 4.9 kg).Conclusion: Initiation and titration of U-500R using either algorithm (TID or BID) improves glycemic control effectively and safely with fewer injections in patients with T2D treated with high-dose/high-volume U-100 insulin. These results provide clinicians with a practical framework for using U-500R in severely insulin-resistant patients with suboptimally controlled T2D.Abbreviations: BID = twice daily FAS = full analysis set HbA_1c = glycated hemoglobin PG = plasma glucose SMPG = self-monitored plasma glucose T2D = type 2 diabetes TDD = total daily dose TID = thrice daily U-500R = human regular U-500 insulin     

Cytosol-Membrane Interface of Human Erythrocytes: A Resonance Energy Transfer Study

The resonance energy transfer from donors embedded in the membrane of erythrocytes to the cytosol hemoglobin has been measured by comparing the donors' fluorescence decay in ghosts and in intact cells. A series of n - (9-anthroyloxy) stearic acids (n-AS) (n = 2, 6, 9, 12) and similar probes were used as donors, and their locations within the outer leaflet of the phospholipid bilayer were determined from their average efficiency of energy transfer, <T>. The energy transfer data for several membrane probes were analyzed according to a simple semiempirical model, in which the heme acceptors are assumed to form a semiinfinite continuum beyond a plane, whose normal distance (d) from particular donors may be determined if the heme density in the cytosol boundary layer is known. The hemoglobin concentration in the erythrocytes was varied by suspending the cells in buffers of different ionic strengths. This made it possible to study the ionic strength dependence of the heme concentration averaged over the cell (h_c), as well as that in the boundary layer (h_b). Both level off above approximately 600 mosM, as does the ratio h_b/h_c. By using the maximum heme concentration that can be obtained in osmotically shrunken cells as a limiting value, h_b is estimated to be 17 mM or less, under physiological conditions; and from the measured <T> for various probes, the distance d was found to range from 40 Å for 2-AS to 31 Å for 12-AS and 26 Å for 9-vinyl anthracene (9-VA). It is concluded that the hydrophobic probe 9-VA is located near the center of the phospholipid bilayer and that the cytosol hemoglobin is in contact with the inner membrane surface, or nearly so. This conclusion is valid for oxy- and deoxy-hemoglobin, and is shown to be independent of several systematic errors that might arise from the simple assumptions of the model used. The steady-state fluorescence anisotropy of the probes was found to decrease as they approach the bilayer's central plane. The methodology developed here may be used to extend studies of cytosol membrane interactions in ghost systems to intact cells, and is useful in the investigation of the morphology of normal and pathological intact erythrocytes.     

The fatty acid composition of phospholipids and absorption spectra of lipid extracts from lamprey,frog, and rat erythrocytes

The work studies the content and fatty acid composition of phospholipids as well as the absorption spectra of lipid extracts from red blood cells of poikilothermal and homoiothermal animals at different evolutionary levels. The objects of study include two poikilothermal species, the river lamprey (Lampetra fluviatilis) that uses oxygen dissolved in water, and the common frog (Rana temporaria) that consumes oxygen both from water and from air. A homoithermal animal is the white rat (Rattus rattus) that inhabits the terrestrial-aerial environment. The animals are studied in winter and spring. The phospholipid content in lamprey blood plasma is found to be twice higher than that in its erythrocytes. In the frog and the rat, the ratio is reverse. Determination of the fatty acid lipid composition of red blood cell phospholipids suggests that membranes in the lamprey are denser than in the frog. As for the fatty acids in the erythrocyte fraction of rat blood, they appear to be less diverse, with a double prevalence of saturated acids over unsaturated ones and devoid of long chain (C22) ω3 fatty acids. All of this results in a lower degree of unsaturation and a denser packing of fatty acids in the membrane structures of rat erythrocytes. The mechanism of reversible binding of O₂ molecules to hemoglobin in erythrocytes is discussed. Presumably, the mechanism of interaction between molecules of O₂ and molecules of water prevents the exchange interaction of electrons of the hemoglobin iron atoms with an oxygen molecule. This is confirmed by our obtained absorption spectra, which show that in the lipid extract almost totally devoid of water the heme isolated from erythrocytes is converted to hemin.