The accuracy of drawing up insulin by insulin treated diabetics

The accuracy of drawing up insulin was tested in a group of randomly selected insulin requiring diabetics. The mean error between patients of drawing up rapid acting insulin was + 5.6%, of intermediate acting insulin, + 4.9% and of a mixture of rapid and intermediate acting insulin, + 1.8%. There was no correlation in percentage error in drawing up insulin the age of patient, duration of diabetes, dosage of insulin nor quality of diabetic control.     

Time-action characteristics of regular and NPH insulin in insulin-treated diabetics

The time course of action of regular and NPH insulins injected sc was studied in 15 insulin-treated diabetics over a 24-h period during which they received a constant infusion of glucose. The blood glucose began to decline in 1.2 +/- 0.1 h (range, 0.5--2) and reached its nadir in 5.7 +/- 0.3 h (range, 4--8) after the sc injection of regular insulin. The peak effect of regular insulin usually persisted for several hours, and the total duration of action was 16.2 +/- 1.1 h (range, 9--24). Both the time of peak effect and the total duration of action were considerably prolonged compared to data provided in standard textbooks. Free insulin increased to a peak in 2.7 +/- 0.3 h (range, 1--4) after regular insulin injection and then returned to baseline by 8.8 +/- 0.96 h. Subcutaneous injection of NPH insulin decreased the blood glucose by 2.4 +/- 0.5 h (range, 1--7), with a maximal effect at 11.0 +/- 1.4 h (range, 5--19). The total duration of effect on blood glucose was 25.1 +/- 0.7 h (range, 20--29). These values are similar to those in standard textbooks. Although the total insulin levels increased after the injection of NPH insulin, there was very little if any elevation in free insulin. Recognition of the prolonged effect of regular insulin is important in establishing an insulin treatment regime for diabetic patients.     

Adaptation to hyperglycemia enhances insulin secretion in glucokinase mutant mice

The present study was undertaken to test the hypothesis that exposure to high glucose concentrations enhances insulin secretion in pancreatic islets from glucokinase-deficient mice. Insulin secretion and intracellular calcium ([Ca2+]i) were measured as the glucose concentration was increased from 2 to 26 mmol/l in islets from heterozygous glucokinase (GK)-deficient mice (GK+/-) and their wild-type littermates (GK+/+). Results obtained in islets incubated in 11.6 or 30 mmol/l glucose for 48-96 h were compared. GK+/- islets that had been incubated in 30 mmol/l glucose showed improved although not normal insulin secretory and [Ca2+]i responses to the standard glucose challenge as well as an enhanced ability to sense small amplitude glucose oscillations. These effects were associated with increased glucokinase activity and protein. In contrast, exposure of GK+/+ islets to 30 mmol/l glucose increased their basal insulin secretion but reduced their incremental secretory responses to glucose and their ability to detect small amplitude glucose oscillations. Thus exposure of GK+/- islets to 30 mmol/l glucose for 48-96 h enhanced their ability to sense and respond to a glucose stimulus, whereas similar exposure of GK+/+ islets induced evidence of beta-cell dysfunction. These findings provide a mechanistic framework for understanding why glucokinase diabetes results in mild hyperglycemia that tends not to increase over time. In addition, the absence of one allele of the glucokinase gene appears to protect against glucose-induced beta-cell dysfunction (glucose toxicity).     

The spontaneous rhythm of the peripheral blood supply in diabetics needing insulin

In order to study the spontaneous rhythmics of the peripheral blood supply under diabetic metabolic onditions with the help of venous occlusion plethysmography quantitative measurings were carried out in 20 long-term diabetics treated with insulin and in an adequate control group with healthy metabolism. The results were significant differences of the sizes of blood flow in rest as well as in the behaviour of the amplitudes and in the course of time of the spontaneous rhythmical varieties of the blood supply. Influences of age and duration of diabetes could not be proved on the basis of the number of patients. As to their evidence the findings are discussed with regard to the pathogenesis and early recognition of the diabetic neuro- and angiopathy.     

Prospects for insulin delivery by ex-vivo somatic cell gene therapy

The principle of insulin delivery by ex-vivo somatic cell gene therapy involves the removal of non-B-cell somatic cells (e.g. fibroblasts) from a diabetic patient, and genetically altering them in vitro to produce and secrete insulin. The cells can be grown in culture and returned to the donor as a source of insulin replacement. Cells modified in this way could be evaluated before implantation, and reserve stocks could be cryopreserved. By using the patient's own cells, the procedure should obviate the need for immunosuppression and overcome the problem of tissue supply, while avoiding a recurrence of cell destruction. Ex-vivo somatic cell gene therapy requires an accessible and robust cell type that is amenable to multiple transfections and subject to controlled proliferation. Special problems associated with the use of non-B-cell somatic cells include the processing of proinsulin to insulin, and the conferment of sensitivity to glucose-stimulated proinsulin biosynthesis and regulated insulin release. Preliminary studies using fibroblasts, pituitary cells, kidney (COS) cells and ovarian (CHO) cells suggest that these challenges could be met, and that ex-vivo somatic cell gene therapy offers a feasible approach to insulin replacement therapy.     

Benfluorex normalizes hyperglycemia and reverses hepatic insulin resistance in STZ-induced diabetic rats

We have examined the effect of chronic (20 days) oral administration of benfluorex (35 mg/kg) in a rat model of NIDDM, induced by injection of STZ 5 days after birth and characterized by frank hyperglycemia, hypoinsulinemia, and hepatic and peripheral insulin resistance. We assessed the following: 1) basal blood glucose and insulin levels, 2) glucose tolerance and glucose-induced insulin release in vivo and in vitro, and 3) basal and insulin-stimulated in vivo glucose production and glucose utilization, using the insulin-clamp technique in conjunction with isotopic measurement of glucose turnover. The in vivo insulin response of several individual tissues also was evaluated under the steady-state conditions of the clamp, using the uptake of the glucose analogue 2-deoxy-D-glucose as a relative index of glucose metabolism. In the benfluorex-treated diabetic rats, postabsorptive basal plasma glucose levels were decreased (8.1 +/- 0.2 mM compared with 10.5 +/- 0.5 mM in the pair-fed untreated diabetic rats and 6.1 +/- 0.2 mM in the benfluorex-treated nondiabetic rats), whereas the basal and glucose-stimulated intravenous glucose tolerance test plasma insulin levels were not improved. Such a lack of improvement in the glucose-induced insulin release after benfluorex treatment was confirmed under in vitro conditions (perfused pancreas). In the pair-fed untreated diabetic rats, the basal glucose production and overall glucose utilization were significantly increased, and during hyperinsulinemia both liver and peripheral tissues revealed insulin resistance. In the benfluorex-treated diabetic rats, the basal glucose production and basal overall glucose utilization were normalized. After hyperinsulinemia, glucose production was normally suppressed, whereas overall glucose utilization was not significantly improved.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of LysB28, ProB29-human insulin analog and regular human insulin in the correction of incidental hyperglycemia

OBJECTIVE: To obtain clinically applicable data on the effects of regular human insulin and the LysB28,ProB29-human insulin analogue (lispro) on the correction of incidental hyperglycemia. RESEARCH DESIGN AND METHODS: The insulins were compared in a non-clamped randomized crossover study of 27 male IDDM patients. Hyperglycemia was induced by the withdrawal of the normal evening dose of insulin; the next morning patients fasted and received a single dose of study insulin according to a dosing nomogram. Blood glucose concentration and GR (a measure of glucose corrected for differences in administered insulin dose: GR = glucose concentration X BMI X insulin dose-1) were followed for 4 h. RESULTS: The time courses of blood glucose concentration and GR were significantly different after regular insulin in comparison with lispro (multiple analysis of variance, P < 0.001). At t = 120 min, glucose concentrations had decreased 1.4 mmol/l more with lispro than with regular insulin (95% confidence interval [CI] 0.6-2.3, P = 0.002). Similarly, GR had decreased 4.4 mol.kg.IU-1.m-5 more with lispro than with regular insulin (95% CI 2.6-6.2, P < 0.001). The overall difference in glucose values was 0.87 mmol/l (lispro < regular insulin, P = 0.036), and the overall difference in GR values was 1.96 mol.kg.IU-1.m-5 (lispro < regular insulin, P = NS). Unexpectedly, the intrinsic variability of GR was higher for lispro than for regular insulin. CONCLUSIONS: The more rapid action of lispro is an advantage in the correction of hyperglycemia, even though actual differences in glucose concentrations are smaller than suggested by previous clamped studies.     

Novel methods of insulin delivery: an update

Conventional insulin therapies involve multiple daily subcutaneous injections. However, the resultant disposition of insulin and blood glucose differs considerably from that following the physiological secretion of pancreatic insulin. A variety of alternative routes/methods have been investigated to improve systemic insulin delivery. Peroral and nasal insulin administration have demonstrated good potential for the treatment of diabetes. Facilitated transdermal delivery has also enjoyed success in promoting the systemic delivery of insulin. In addition, pulmonary, buccal, and ocular insulin administration have been shown to decrease serum glucose concentrations. Other methods that have been investigated for their potential in systemic insulin delivery include rectal, vaginal, and uterine routes.     

Effects of insulin therapy on non-insulin-dependent diabetics with secondary oral hypoglycemic agent failure

A recent trend among physicians is the categorisation of lung scans as normal [excludes pulmonary embolism (PE)], high probability (confirms PE) and non-diagnostic (no judgement on PE risk). The low probability scan is therefore being eliminated as a functional category. This occasional survey contends that such an approach is misguided. Correction of the original PIOPED data with certain assumptions provides a more reproducible, albeit restricted, low probability scan category which excludes PE in 97% of cases in the low pre-test clinical category. Patients with a low probability scan with risk factors for PE (i.e. medium clinical risk) will require further investigation. More important, the very low probability scan category excludes PE in 98% of patients with low and more than 92% of patients with medium pre-test clinical likelihood. The demise of "low probability" is premature.     

Modification of postprandial hyperglycemia with insulin lispro improves glucose control in patients with type 2 diabetes

OBJECTIVE: Insulin lispro is a rapid-acting analog of human insulin that can be used to target the postprandial rise in plasma glucose. We designed an open-label randomized crossover study of type 2 diabetic patients with secondary failure of sulfonylurea therapy to determine whether improvement of postprandial hyperglycemia would affect total daily glucose control. RESEARCH DESIGN AND METHODS: Twenty-five type 2 diabetic patients who were poorly controlled on a maximum dose of sulfonylureas were studied in a university hospital clinical research center. In one arm of the study, patients continued therapy with maximum-dose sulfonylureas. In the other arm, patients used a combination therapy with insulin lispro before meals and sulfonylureas. After 4 months, patients were crossed over to the opposite arm. Fasting plasma glucose (FPG) and 1- and 2-h postprandial glucose (after a standardized meal), HbA1c, total, HDL, and LDL cholesterol, and triglyceride levels were measured at the end of each arm of the study. RESULTS: Insulin lispro in combination with sulfonylurea therapy significantly reduced 2-h postprandial glucose concentrations compared with sulfonylureas alone, from 18.6 to 14.2 mmol/l (P < 0.0001), and incremental postprandial glucose area from 617.8 to 472.9 mmol.min.1-1 (P < 0.0007). FPG levels were decreased from 10.9 to 8.5 mmol/l (P < 0.0001), and HbA1c values were reduced form 9.0 to 7.1% (P < 0.0001). Total cholesterol was significantly decreased in the lispro arm from 5.44 to 5.10 mmol/l (P < 0.02). HDL cholesterol concentrations were increased in the lispro arm from 0.88 to 0.96 mmol/l (P < 0.01). The patients weighed significantly more after lispro therapy than after sulfonylureas alone, but the difference was small in absolute terms (sulfonylurea therapy alone, 90.6 kg; lispro therapy, 93.8 kg; P < 0.0001). Two episodes of hypoglycemia (glucose concentrations, < 2.8 mmol/l) were reported by the patients while using lispro. CONCLUSIONS: Previously, it has not been possible to address the effect of treatment of postprandial hyperglycemia specifically. We have now shown that the treatment of postprandial hyperglycemia with insulin lispro markedly improves overall glucose control and some lipid parameters in patients with type 2 diabetes.     

Control of spine formation by electrical activity in the adult rat cerebellum

Dendritic spines are a key structure in neuronal plasticity. Enhanced activity is commonly associated with an increase in spine size and density. Purkinje cell dendrites are characterized by a proximal and a distal compartment on which climbing fibers and parallel fibers, respectively, impinge. The proximal region has a very low spine density, whereas the distal region has a high density. Previous experiments showed that after climbing fiber deletion, Purkinje cells become hyperactive, and a large number of spines develop on the proximal dendrites. Here we show that the same hyperspiny transformation occurs in the proximal dendrites of adult Purkinje cells by depressing electrical activity with tetrodotoxin. Thus, spines in different dendritic compartments are created or maintained independently from the level of Purkinje cell-firing rate and when the afferent activity is blocked. This conclusion supports the view that spinogenesis is the expression of an intrinsic program and the two regions of the dendritic tree respond differently to activity block because of differences in the inputs that they receive. On tetrodotoxin treatment, climbing fibers become atrophic and may sprout thin collateral ramifications directed mainly toward the granular layer. All changes are reversible on tetrodotoxin removal. Therefore, Purkinje cells provide a model where spines in different compartments of the same neuron are differently regulated by the activity of their local afferents. In addition, electrical activity is also essential to maintain the full climbing fiber innervation.     

Reduced number of circulating monocytes after institution of insulin therapy--relevance for development of atherosclerosis in diabetics?

Twelve patients with Type II diabetes mellitus, insufficiently controlled with oral hypoglycemic agents, were studied before, after 2 months, and after 4 months on insulin therapy. For comparison the same variables were also studied in 10 healthy subjects. From the start, in the diabetic group, the authors found alterations in the hemorheologic parameters indicated by increased values for whole blood viscosity, plasma viscosity, red cell transit time (RCTT), and decreased values for white cell initial relative filtration rate (IrFR). In hematologic parameters they found increased values for mean corpuscular volume (MCV), leukocyte count, counts of neutrophils and monocytes, and a decreased count of lymphocytes. They also found increased values in the lipid parameters P-triglycerides and Apo B/Apo A-I ratio, risk factors of coronary atherosclerosis. After 4 months of insulin treatment whole blood and plasma viscosity were still increased, but there was a partial improvement of lipoprotein abnormalities. Red and white cell filterability, however, tended to normalize. These results indicate that changes in blood cell filterability do not necessarily influence in vitro measurements of blood viscosity. The change in RCTT during the insulin treatment was associated with a decreased MCV and the change in white cell IrFR with a decrease in the number of monocytes. This change of white cell filterability during insulin therapy, probably due to a reduced number of monocytes, may be of interest in the study of atherosclerosis and circulatory disease in diabetics.     

Control of erythropoietin delivery by doxycycline in mice after intramuscular injection of adeno-associated vector

We reported previously that controlled expression of a foreign gene in response to tetracycline derivative can be accomplished in mice by the autologous transplantation of retrovirus-modified muscle cells. Although regulated systemic delivery of therapeutic proteins from engineered tissues has potential clinical application, the transplantation of muscle cells is not currently feasible in humans. Several studies have shown that a single injection of adeno-associated virus (AAV) vectors into mouse muscle results in long-term expression of reporter genes as well as sustained delivery of proteins into the serum. Because this method is potentially applicable clinically, we constructed an AAV vector in which the expression of the mouse erythropoietin (Epo) cDNA is modulated in response to doxycycline. The vector was injected intramuscularly in normal mice. We observed that hematocrit and serum Epo concentrations could be modulated over a 29-week period in response to the presence or absence of doxycycline in the drinking water of these animals. Thus, a regulated gene expression cassette can be incorporated into a single AAV vector, such that intramuscular injection of the vector allows sustained and regulated expression of a desired gene.     

Alterations in reverse cholesterol transport associated with programmable implantable intraperitoneal insulin delivery

OBJECTIVE: As the population ages, the care of older persons becomes more important. At the same time, practice guidelines that provide recommendations for appropriate care are being published in greater numbers. The purpose of this work is to determine the proportion of guidelines that contain specific information about older persons. DESIGN: Through a random sample of published guidelines listed in the AMA Directory of Practice Parameters, 1992 Edition, we determined the proportion of guidelines that contain specific age-related information. We also determined if, over time, there was a difference in the proportion of practice guidelines containing information about older persons. RESULTS: 45.9% (95% CI, range 33.4-58.4) of guidelines that could conceivably pertain to older persons contain no age information; 24.6% (95% CI, range 13.8-35.4) of guidelines contain information only about persons less than 65 years of age; 29.5% (95% CI, range 18.1-41.0) of guidelines contain specific information about older persons. Moreover, there were no secular trends in the proportion of guidelines pertaining to older persons. CONCLUSIONS: Only a minority of practice guidelines contain information about older persons. Possible causes and solutions to this shortfall are discussed.     

Prevention of atherosclerosis in diabetics

The high prevalence of atherosclerotic (macrovascular) complications in diabetes (1.5-6x higher than in non-diabetics) stimulated evaluation of new pathogenetic findings which could have an impact on prevention. In type 1 diabetics the development of nephropathy is a factor hastening the development of macroangiopathy. In type 2 diabetics on whom attention is concentrated at the moment interaction of various metabolic deviations is involved which include changes of lipoproteins (drop of HDL, changes in the size and composition of LDL), insulin resistance and glycosylation of proteins. There is an enhanced tendency to lipoprotein oxidation (LDL) which promote the development of cholesterol rich plaques in the arterial walls. Their rupture may cause occlusion and ensuing risks for life. Possibilities of prevention are not adequately made use of. This is due to a tendency to underrate the serious character of type 2 diabetes and also the high percentage of diabetics where the disease was diagnosed late. The metabolic syndrome which develops as a result of insulin resistance precedes for years manifestations of diabetes. Its detection makes it possible to screen subjects at risk, some of whom develop diabetes. At the same time it is also a pathogenetic factor of macrovascular complications. It leads to the cumulation of a number of risk conditions. More effective prevention can be implemented by intervention of all associated risk factors (smoking, hypertension), in the application of lifestyle provisions of energy reduction by promoting physical activity and by a rational diet (diabetes, obesity, hyperlipidaemia). The justification of pharmacotherapy for the high risk groups of diabetics with hyperlipidaemia is supported by results of recently published investigations where statins were used. For the sub-population of subjects at risk the perspective should be screening of risk factors, early diagnosis of diabetes, education, continuous primary care, comprehensive prevention using lifestyle provisions as well as advances in modern pharmacotherapy.     

Induction of glycosuria and hyperglycemia by topical corticosteroid therapy

A patient with psoriasis is described who had an abnormal response to the glucose tolerance test without other evidence of diabetes and then developed postprandial hyperglycemia and glycosuria during a period of topical administration of a corticosteroid cream, halcinonide cream 0.1%, under occlusion. A second patient with a similar glucose tolerance test result showed postprandial hyperglycemia when treated similarly with betamethasone valerate cream 0.1%. Two additional patients with midly abnormal responses to glucose tolerance tests showed no evidence of altered glucose metabolism when treated with halcinonide cream in a similar manner.     

Acute hemodynamic effects of pulsed delivery of low flow nasal nitric oxide in children with pulmonary hypertension

DNA duplex and dumbbells containing chemically active acylphosphate internucleotide groups were synthesized. To obtain these compounds the chemical ligation method was used. The acylphosphate group was inserted into a DNA duplex and dumbbells as a result of template-directed condensation of 5'-phosphate and especially introduced 3'-carboxy groups of oligonucleotides. 1-Ethyl-3-(3'-dimethylaminopropyl)carbodiimide (EDC) was used as a condensing agent. Oligonucleotides containing a carboxy group were obtained by the interaction of their 3'-phosphate with glycine methyl ester under the action of EDC, followed by ester hydrolysis. The yields of acylphosphate-containing double-stranded oligonucleotides achieved 15-25% depending on the structure of their precursors. It was shown that these compounds are acylating agents and are efficiently cleaved in near-physiological conditions under the action of ethylenediamine or N-methylimidazole. These results indicate that double-stranded oligonucleotides carrying acylphosphate internucleotide groups could constitute new crosslinking reagents for affinity modification of DNA recognizing proteins.