AMPK activation restores the stimulation of glucose uptake in an in vitro model of insulin-resistant cardiomyocytes via the activation of protein kinase B

Diabetic hearts are known to be more susceptible to ischemic disease. Biguanides, like metformin, are known antidiabetic drugs that lower blood glucose concentrations by decreasing hepatic glucose production and increasing glucose disposal in muscle. Part of these metabolic effects is thought to be mediated by the activation of AMP-activated protein kinase (AMPK). In this work, we studied the relationship between AMPK activation and glucose uptake stimulation by biguanides and oligomycin, another AMPK activator, in both insulin-sensitive and insulin-resistant cardiomyocytes. In insulin-sensitive cardiomyocytes, insulin, biguanides and oligomycin were able to stimulate glucose uptake with the same efficiency. Stimulation of glucose uptake by insulin or biguanides was correlated to protein kinase B (PKB) or AMPK activation, respectively, and were additive. In insulin-resistant cardiomyocytes, where insulin stimulation of glucose uptake was greatly reduced, biguanides or oligomycin, in the absence of insulin, induced a higher stimulation of glucose uptake than that obtained in insulin-sensitive cells. This stimulation was correlated with the activation of both AMPK and PKB and was sensitive to the phosphatidylinositol-3-kinase/PKB pathway inhibitors. Finally, an adenoviral-mediated expression of a constitutively active form of AMPK increased both PKB phosphorylation and glucose uptake in insulin-resistant cardiomyocytes. We concluded that AMPK activators, like biguanides and oligomycin, are able to restore glucose uptake stimulation, in the absence of insulin, in insulin-resistant cardiomyocytes via the additive activation of AMPK and PKB. Our results suggest that AMPK activation could restore normal glucose metabolism in diabetic hearts and could be a potential therapeutic approach to treat insulin resistance.     

Pharmacological approach in the treatment of insulin resistance.

Insulin resistance syndromes are heterogeneous in either severity or mechanism. Many drugs have been shown to counteract various elements of insulin resistance. Some of them, by normalization of metabolic parameters, decrease insulin resistance induced by chronic hyperglycemia in diabetes. Insulin and, to some extent, sulfonylureas are in this group, but these drugs are not stricto sensu medication of insulin resistance. Some drugs sensitize peripheral tissues to the action of insulin. For instance, biguanides and thiazolidine-dione facilitate translocation to the membrane of glucose transporter in presence of insulin. Other compounds as vanadate or IGF-1 mimic some peripheral action of insulin. Finally, blockade of FFA oxidation by specific inhibitors (methylpalmoxyrate) can limit insulin resistance. In 1992, among these compounds, specific of insulin resistance, biguanides are mostly used. However, the efficacy of these drugs is moderate and limited to type 2 diabetes.     

Hypoglycemic activities of MTP-3631, a novel thiopyranopyrimidine derivative.

MTP-3631 is a novel thiopyranopyrimidine derivative structurally different from any existent hypoglycemic agents. MTP-3631 markedly decreased basal blood glucose and improved glucose intolerance in genetically diabetic C57BL/6J ob/ob mice, which was not affected by tolbutamide. MTP-3631 also caused hypoglycemic effects in normal rats, but no change was observed in plasma insulin level. Unlike buformin, MTP-3631 did not change plasma lactate level in ob/ob mice. These results suggest that the hypoglycemic mechanism of MTP-3631 may be essentially different from those of sulfonylureas and biguanides.     

Studies on Whole-body Potassium in Non-ketoacidotic Diabetics Before and After Treatment

Serial measurements of whole-body potassium were carried out in 28 diabetic patients, in 23 of whom diabetes had only recently been diagnosed. Eleven patients were treated with insulin, 12 with oral hypoglycaemic agents, and the rest were already on oral hypoglycaemic agents and had developed poor diabetic control; four of these required insulin. Whole-body potassium was measured before treatment was begun (or altered) and again one and six weeks later. Whole-body potassium (ratio of observed to expected) was initially reduced in most of the patients requiring insulin. After control of diabetes whole-body potassium increased significantly in the three groups. The increase in whole-body potassium in the individual patients varied over a wide range, and in patients who were treated with insulin it was often of a similar magnitude to that observed in patients in diabetic ketoacidosis.     

Postprandial changes in cytosolic free calcium and glucose uptake in adipocytes in obesity and non-insulin-dependent diabetes mellitus

We evaluated the possible relationship between [Ca2+]i and glucose uptake in the postabsorptive state and postprandially in adipocytes obtained from normal and obese subjects, as well as from patients with non-insulin-dependent diabetes mellitus (NIDDM). Adipocytes isolated from overnight-fasted obese and NIDDM patients revealed high levels of [Ca2+]i (p less than 0.05 vs. control) in association with a decreased insulin-stimulated glucose uptake (p less than 0.05 vs. controls). In obese and NIDDM patients treated with oral hypoglycemic agents, the overnight fasting levels of [Ca2+]i were increased postprandially (p less than 0.05), concomitantly with a further decrease in insulin-stimulated 2-deoxyglucose uptake. Although the precise nature of the relationship between [Ca2+]i in specific insulin target tissues and diminished insulin action remains unknown, it is clear that high levels of [Ca2+]i may contribute to the development of insulin resistance.     

Ultrasonic coagulometry as a method of testing compounds with antiplasmin activity

An ultrasonic interferometer has been used to study the process of fibrin clot lysis according to the decrease in the rate of propagation of an ultrasonic wave in the latter. A significant decrease in the sound fall rate on adding epsilon-aminocaproic and trans-4-aminomethylcyclohexanecarbonic acids to the system indicates their activity inhibiting fibrinolysis. N-nicotinoyl derivatives of this compounds possess less pronounced antiplasmin activity.     

Comparison of metformin and chlorpropamide in non-obese,maturity-onset diabetics uncontrolled by diet.

The clinical effectiveness of metformin was compared with that of chlorpropamide in closely similar groups of 216 non-obese patients recently diagnosed as cases of maturity-onset diabetes that could not be controlled by diet. The incidences of primary and secondary drug failures in each group and the numbers of patients satisfactorily maintained on each of the hypoglycaemic agents throughout the first year proved remarkably similar. In 61 of the successfully treated patients who were studied by crossover to the other drug and observed for a further year the mean blood glucose concentrations at the end of the year were roughly comparable, but the mean weight response was a small loss of 1.5 +/- 3.8 kg with metformin but a gain of 4.6 +/- 3.9 kg with chlorpropamide. Thus for non-obese, maturity-onset diabetics whose disease cannot be controlled by diet and who require oral treatment sulphonylureas and biguanides are equally effective, the choice depending on whether the patient is underweight and the severity of symptoms.     

Obesity in type 2 diabetes: prevalence, treatment trends and dilemmas

This retrospective observational study investigated the prevalence of obesity in persons with type 2 diabetes, trends in obesity resulting from the duration and treatment of diabetes, and treatment-related changes in HbA1c and body mass index (BMI). Data on 1773 type 2 diabetics (802 men and 971 women) were obtained from the CroDiabNET registry. Follow-up included the analysis of patients' age, disease duration, diabetes treatment, BMI and HbA1c values. A significantly higher rate of overweight and obesity was found in persons with type 2 diabetes as compared to the general population. A significant decrease in BMI was observed in the groups treated by diet, and in those treated by oral hypoglycaemic agents (p < 0.05), regardless of their pharmacotherapeutic group, in contrast to a significant increase in BMI observed in the groups treated with insulin (alone or in combination with oral hypoglycaemic agents) (p < 0.05). Persons with type 2 diabetes lost weight only during the first years of the disease, while with diabetes duration and insulin treatment they regained weight. A significant increase in HbA1c was observed in the groups treated with sulfonylureas (p < 0.05), whereas all other groups revealed either a significant decrease (p < 0.05) or no change in HbA1c. Our findings suggest the necessity of an integrated approach to managing type 2 diabetic patients that would simultaneously address both diabetes and obesity. Good glycaemic control is imperative and diabetes treatment should not be postponed. Because of a possible concomitant weight gain, aggressive weight control measures should be applied concurrently in order to achieve maximum treatment benefit.     

护理干预在胰岛素泵强化治疗中的作用研究

目的:探讨护理干预对临床使用胰岛素泵治疗糖尿病效果的影响。方法:在161例用口服降糖药及常规胰岛素皮下注射进行血糖控制但效果不佳的糖尿病患者使用胰岛素泵治疗过程中,护理人员对其进行心理护理、置泵前告之患者用胰岛素泵治疗的方法、低血糖的预防、输部位的正确选择等全方位护理。结果:在胰岛素泵使用过程中,护理人员全面、细致、持续的干预达到使用的最佳效果。结论:护理干预是糖尿病患者学会正确的自我管理、自我保健知识和泵使用的各种技术的关键,同时也是保证糖尿病患者胰岛素泵治疗顺利进行的基础和关键。     

Dynamic changes of fibrin architecture during fibrin formation and intrinsic fibrinolysis of fibrin-rich clots

Clotting and fibrinolysis are initiated simultaneously in vivo, and fibrinolysis usually occurs without any individualized lysis front (intrinsic fibrinolysis). We have developed a novel model to assess whether morphological changes resulting from intrinsic fibrinolysis are similar to those previously reported at the lysis front using externally applied lytic agents. Fibrin assembly and fibrinolysis were followed in real-time by confocal microscopy using gold-labeled fibrinogen molecules. An increase in fiber absorbance (30%, p < 0.01) and a decrease in fiber diameter (60%, p < 0.01) due to the ongoing accumulation and packing of fibrin molecules were the most significant detectable features occurring during fibrin assembly. Similar features with a similar magnitude were observed during fibrin dissolution, but in the reverse order and with a 3-fold increase in duration. Then, lysing fibers were progressively transected laterally, and thinner fibers were cleaved at a 2.5-fold faster rate than thicker fibers (p < 0.001). Frayed lysing fibers were seen to interact progressively with adjoining fibers (agglomeration), leading to a 76 and 88% increase in the network pore diameter (p < 0.05) and fiber diameter (p < 0.01), respectively. At the maximum decrease in fiber absorbance (46%, p < 0.05), the network suddenly collapsed with the release of large fragments that gradually vanished. Morphological changes of fibrin that occur during intrinsic fibrinolysis are similar as those observed next to the lysis front, although they are not restricted spatially to the clot/surrounding milieu interface but are observed through the entire clot.     

Protein C and plasma serine protease inhibitors in patients with essential hypertension]

Plasma protein C and serine protease inhibitors together with some other hemostasis parameters have been determined in 60 patients with essential hypertension. Significant decrease in protein C and alpha 2-antiplasmin levels, increased fibrinogen, fibrinopeptide A, WF: Ag, plasminogen, and prolongation of euglobulin fibrinolysis time have been observed. Results indicate hypercoagulability and fibrinolysis defect in hypertensive patients.     

Diabetes Mellitus: Distinguishing Between Patients Receiving Insulin and Those Requiring Insulin Therapy

Fifteen patients with maturity onset type diabetes, all of whom had received insulin for periods of one to thirty-five years, were admitted to hospital and insulin treatment was discontinued. Within 24 to 48 hours each patient was given an intravenous tolbutamide test, following which all were given either diet therapy alone or diet therapy plus oral agents. If significant hyperglycemia or ketonemia resulted, insulin therapy was reinstituted.Approximately 50 percent (8 of 15) of the patients showed improvement in fasting blood sugar levels following discontinuation of insulin. It was not possible to distinguish the insulin independent from the insulin dependent group using such criteria as age, sex, degree of overweight, insulin dosage, duration of diabetes or duration of insulin therapy. However, using the intravenous tolbutamide test it was possible to differentiate between the two groups. Those who did not require insulin responded to intravenous tolbutamide with a glucose decrease greater than 10 percent from the initial value. The insulin dependent group had either no glucose decrease or a rise in blood glucose following intravenous administration of tolbutamide.     

Liver Transplantation in Man—IV,Haemorrhage and Thrombosis

Blood coagulation and fibrinolytic factors have been measured in 13 patients treated by liver transplantation. During operation intravascular coagulation and fibrinolysis were increased, but seldom to a degree which would cause abnormal bleeding. Measurement of the catabolism of radioactive fibrinogen showed that increased intravascular coagulation continued for long periods after the operation. Despite secondarily increased fibrinolysis, there was a high incidence of thrombosis. Treatment with anticoagulants or with fibrinolysis inhibitors may be valuable in these patients.     

Design,synthesis and in vitro anticancer evaluation of 4,6-diamino-1,3,5-triazine-2-carbohydrazides and -carboxamides

Series of substituted 4,6-diamino-1,3,5-triazine-2-carbohydrazides and -carboxamides have been synthesised, based on molecular modelling of candidate structures related to the previously reported Rad6B-inhibitory diamino-triazinylmethyl benzoate anticancer agents TZ8 and TZ9. Synthesis of the target compounds was readily accomplished in two steps from aryl biguanides via reaction of phenylhydrazine or benzylamines with key 4-amino-6-(arylamino)-1,3,5-triazine-2-carboxylate intermediates. These new triazine derivatives were tested for in vitro anticancer activity against the Rad6B expressing human breast cancer cell lines MDA-MB-231 and MCF-7. Active compounds, such as the triazinyl-carbohydrazides 3a–e, were found to exhibit low micromolar IC₅₀ values particularly in the Rad6B-overexpressing MDA-MB-231 cell line.     

Effects of beta-mercaptoethanol and hydrogen peroxide on enzymatic conversion of human proinsulin to insulin

Human insulin is a hormone well-known to regulate the blood glucose level. Recombinant preproinsulin, a precursor of authentic insulin, is typically produced in E. coli as an inactive inclusion body, the solubilization of which needs the addition of reducing agents such as beta-mercaptoethanol. To make authentic insulin, recombinant preproinsulin is modified enzymatically by trypsin and carboxypeptidase B. The effects of beta-mercaptoethanol on the formation of human insulin derivatives were investigated in the enzymatic modification by using commercially available human proinsulin as a substrate. Addition of 1 mM beta-mercaptoethanol induced the formation of various insulin derivatives. Among them, the second major one, impurity 3, was found to be identical to the insulin B chain fragment from Phe1 to Glu21. Minimization of the formation of insulin derivatives and concomitant improvement of the production yield of human insulin were achieved by the addition of hydrogen peroxide. Hydrogen peroxide bound with beta-mercaptoethanol and thereby reduced the negative effects of beta-mercaptoethanol considerably. Elimination of the impurity 3 and other derivatives by the addition of over 10 mM hydrogen peroxide in the presence of beta-mercaptoethanol led to a 1.3-fold increase in the recovery efficiency of insulin, compared with those for the case without hydrogen peroxide. The positive effects of hydrogen peroxide were also confirmed with recombinant human preproinsulin expressed in recombinant E. coli as an inclusion body.     

护理干预在胰岛素泵强化治疗中的作用研究

目的：探讨护理干预对临床使用胰岛素泵治疗糖尿病效果的影响。方法：在161例用口服降糖药及常规胰岛素皮下注射进行血糖控制但效果不佳的糖尿病患者使用胰岛素泵治疗过程中,护理人员对其进行心理护理、置泵前告之患者用胰岛素泵治疗的方法、低血糖的预防、输部位的正确选择等全方位护理。结果：在胰岛素泵使用过程中,护理人员全面、细致、持续的干预达到使用的最佳效果。结论：护理干预是糖尿病患者学会正确的自我管理、自我保健知识和泵使用的各种技术的关键,同时也是保证糖尿病患者胰岛素泵治疗顺利进行的基础和关键。     

4种抗真菌药物对糖尿病大鼠血糖的影响

目的观察酮康唑、氟康唑、伊曲康唑和特比萘芬与胰岛素组合使用以及单独使用时对糖尿病大鼠血糖水平的影响。方法建立糖尿病大鼠模型,随机分为10组,每组5只。前4组皮下注射胰岛素的同时分别喂食4种抗真菌药物;第5组单独皮下注射胰岛素;第6—9组分别喂食4种抗真菌药物;第10组既不注射胰岛素也不喂食抗真菌药物。定时对糖尿病大鼠尾静脉采血,使用CX5PRO生化检测仪对其血糖进行检测。结果酮康唑、氟康唑和伊曲康唑分别与胰岛素合用时,可使糖尿病大鼠血糖降低（P〈0．05）;不与胰岛素合用时,氟康唑和伊曲康唑均可使糖尿病大鼠血糖升高（P〈0．05）;特比萘芬无论是否与胰岛素合用,对糖尿病大鼠的血糖水平均无影响（P〉0．05）。结论唑类抗真菌药物无论是否与胰岛素合用均会影响糖尿病大鼠的血糖水平,特比萘芬无论是否与胰岛素合用,都不会影响糖尿病大鼠的血糖水平。     

The effects of oral agent or insulin treatments on the plasma lipoproteins and the plasma lipoprotein lipase activator in diabetic patients

The structure and the metabolism of plasma lipoproteins are altered in diabetes mellitus. Insulin or oral agent treatments affect the lipoprotein metabolism in addition to improving hyperglycemia. However, it is not clear whether the alterations seen in lipoproteins during treatment are related to the degree of diabetic control or to the mode of diabetic treatment. The effects of insulin or oral agent treatments on the plasma lipoproteins and lipoprotein lipase activator were compared in a strictly defined non-obese, non-insulin dependent diabetic patient. Both treatment groups had similar plasma triglyceride, total cholesterol, low and high density lipoprotein cholesterol, and lipoprotein lipase activator levels. Lipoprotein lipase activator contents of the very low density lipoproteins correlated positively with their triglyceride (r = 0.803 in insulin, r = 0.828 in oral agent treated patients) and protein (r = 0.713 in insulin, r = 0.862 in oral agent treated patients) contents. The findings of this study indicated that plasma lipid levels, very low density lipoprotein compositions, and lipoprotein lipase activator contents were not significantly different in non-obese, non-insulin dependent diabetic patients treated with either oral hypoglycemic agents or insulin.     

Management of Type 2 Diabetes Mellitus in the Very Elderly: One Practice’s Experience

ObjectiveType 2 diabetes mellitus (T2DM) affects 25% of adults over age 65. Nevertheless, few clinical trials include patients over age 75.MethodsThis case series reports retrospective data on a cohort of 85 patients aged 80 and over (mean 88.1, range 80-104) with T2DM, managed by a single endocrinologist. The practice’s computerized data base was searched for all patients 80 years of age and older with a diagnosis of T2DM.ResultsThe major observations were the significant decrease in the use of agents associated with hypoglycemia (sulfonylureas and insulin), and the beneficial and well-tolerated use of glucagon like peptide-1 receptor analogues (GLP-1 RA). The mean A1c in the entire cohort dropped from 7.6% to 6.6% over a mean of 9 months. Nearly one-half of the cohort were treated with GLP1-RA, reflecting studies demonstrating the safety and efficacy of this class of drugs in less elderly patients. At presentation, 75% were on sulfonylurea and/or insulin; this number was reduced to 27%. Furthermore, none of the patients required short-acting (bolus) insulin to achieve the individualized A1c target.ConclusionPatients with T2DM aged 80 and over respond well to GLP1-RA drugs, drastically reducing the need for agents associated with hypoglycemia. The important question, which will require larger and prospective studies, is whether the lowering of A1c, as shown in this paper, and the use of GLP-1 RA specifically, are associated with improved morbidity and mortality in the very elderly.