Gender Effect on the Relation between Diabetes and Hospitalization for Heart Failure

Cardiovascular risk among diabetic patients is at least twice as much the one for non-diabetic individuals and even greater when diabetic women are considered. Heart failure (HF) is a common unfavorable outcome of cardiovascular disease in diabetes. However, since the comparison among sexes of heart failure prevalence in diabetic patients remains limited, this study is aimed at expanding the information about this point.

We have evaluated the association between diabetes and HF by reviewing the medical records of all subjects discharged from the Internal Medicine and Cardiology Units of all hospitals in the Tuscany region, Italy, during the period January 2002 through December 2008. In particular we sought concomitance of ICD-9-CM codes for diabetes and HF.

Patients discharged by Internal Medicine were on average older, more represented by women, and had a lesser number of individuals coded as diabetic (p<0.05 for all). Relative risk for HF (95% CI) was significantly higher in patients with diabetes, irrespective of gender 1.39 (1.36–1.41) in males; 1.40 (1.37–1.42) in females. When the diabetes-HF association was analyzed according to decades of age, a “horse-shoe” pattern was apparent with an increased risk in 40–59 years old in female patients discharged by Internal Medicine.

Although there is not a difference in the overall HF risk between hospitalized male and female diabetic patients, women have an excess risk at perimenopausal age.

Total plasma homocysteine correlates in women with gestational diabetes

AIM

We aim to assess serum total homocysteine (tHcy) associations with metabolic syndrome components and B-vitamins in women with gestational diabetes mellitus (GDM).

METHODS

We studied 61 consecutive pregnant women, 44 with GDM and 17 with normal glucose tolerance (CG). Serum homocysteine levels were analyzed by ELISA, using Bio-Rad reagents. Serum folates and vitamin B(12) concentrations were determined by chemiluminescent immunoassay, free fatty acids (FFA) and lipids enzymatically.

RESULTS

Serum homocysteine levels were similar in both the GDM and the CG groups (8+/-2.0 vs 7.4+/-1.1 micromol/l, respectively). Women with GDM in comparison to CG women were characterized by higher values of homeostasis model of insulin resistance (HOMA-IR) (2.8+/-1.7 vs 1.6+/-0.9, P<0.01), serum triglycerides (2.7+/-0.9 vs 1.9+/-0.5 mmol/l, P<0.01) and FFA (0.6+/-0.2 vs 0.46+/-0.2 mmol/l, P<0.05). In GDM women serum tHcy correlated with vitamin B(12) (r= -0.47, P<0.01) and folates (r= -0.51, P<0.001); in CG women with HOMA-IR, a marker of insulin resistance (r= -0.49, P<0.05). In multiple regression analysis with serum tHcy as a dependent variable, folate and vitamin B(12) entered the analysis in GDM women (beta= -0.42 and -0.34, respectively, P<0.05), whereas in CG cystatin C and HOMA-IR entered the analysis (P<0.05).

CONCLUSIONS

In women with GDM, serum homocysteine is significantly associated with vitamin B(12) and folate levels, while in healthy pregnant women with HOMA-IR and with kidney function. The results suggest the importance of the B-group vitamins in regulation of serum tHcy levels in women with insulin resistance/gestational diabetes, what might be relevant in protection against pregnancy complications associated with elevated tHcy in GDM women.

Influence of gestational diabetes on the long-term control of glucose tolerance

AIMS/HYPOTHESIS

Gestational diabetes (GDM) carries a high risk of subsequent diabetes. We asked what impact prior GDM has on beta cell function and insulin action in women who maintain normal glucose tolerance (NGT) for a long time.

METHODS

Ninety-one women with NGT (aged 41 +/- 8 years, mean+/-SD) were studied (by mathematical modelling of the C-peptide response to an OGTT) 7 [6] years (median [interquartile range]) after the index pregnancy, during which 52 had GDM (pGDM) and 39 had NGT (pNGT). In all women an OGTT had also been performed at 29 +/- 3 weeks of the index pregnancy.

RESULTS

Women with pGDM were matched with women with pNGT for age, familial diabetes, time and weight gain since index pregnancy, parity, BMI (25.4 +/- 3.9 vs 26.8 +/- 6.4 kg/m(2)), and fasting (4.64 +/- 0.56 vs 4.97 +/- 0.46 mmol/l) and 2 h plasma glucose levels (5.91 +/- 1.14 vs 5.91 +/- 1.21 mmol/l). Nonetheless, fasting (49 [29] vs 70 [45] pmol min(-1) m(-2), p < 0.001) and total insulin secretion (32 [17] vs 48 [21] nmol m(-2), p < 0.0001) and beta cell glucose sensitivity (slope of the insulin secretion/plasma glucose concentration-response function) (95 [71] vs 115 [79] pmol min(-1) m(-2) (mmol/l)(-1), p = 0.025) were reduced in the pGDM group compared with the pNGT group, while insulin sensitivity was preserved (424 [98] vs 398 [77] ml min(-1) m(-2)). At index pregnancy, women with pGDM and those with pNGT had similar age and BMI. However, both insulin sensitivity (359 [93] vs 417 [92] ml min(-1) m(-2), p = 0.0012) and the insulin/glucose incremental area ratio (an empirical index of beta cell function; 98 [74] vs 138 [122] pmol/mmol, p = 0.028) were reduced in women with pGDM.

CONCLUSIONS

Even in women who maintain normal insulin sensitivity, impaired beta cell function is carried over into the NGT status several years after a GDM pregnancy.

Sentinel lymph node biopsy in patients with thick (= 4 mm) melanoma: a single-centre experience

BACKGROUND AND OBJECTIVE

Lymphatic mapping/sentinel lymph node biopsy (LM/SLNB) have become routine techniques for staging the regional lymph nodes in early stage melanoma, yet their role in the management of thick (= 4 mm) melanoma is debated. The aim of the present study is to review our experience with LM/SLNB in a series of patients with thick primary melanoma, to evaluate its utility in this melanoma subset.

PATIENTS AND METHODS

Thirty patients (18 men and 12 women; mean age 70.6 years; median 75 years) with thick primary melanoma underwent LM/SLNB, using both radioisotope and blue dye. The statistical tests were performed by using SAS software for Windows, version 8.2.

RESULTS

The primary tumour sites were head/neck (n = 5; 16.6%), trunk (n = 10; 33.3%), and extremities (n = 15; 50%). Tumour thickness ranged from 4 to 17 mm (mean 5.14 mm; median 4.5 mm). Ulceration was observed in 23 (76.6%) tumours. Eleven patients (36.6%) had at least a positive sentinel lymph node (SLN). The mean follow-up was 27.3 months (median 26 months; range 5-63 months). Patients without SLN metastases had a 5-year disease-free survival rate of 78.9%, vs. 18.2% for patients with SLN metastases (P = 0.0121 by log rank test). The 5-year overall survival rate for patients without SLN metastases was 89.5%, whereas patients with SLN metastases had a 5-year overall survival rate of 36.4% (P = 0.0272 by log rank test).

CONCLUSION

Our retrospective analysis indicates that the SLN status is predictive of recurrence and survival in patients with thick melanoma, and LM/SLNB should be routinely performed in this subset of melanoma patients.

Does parity increase insulin resistance during pregnancy?

AIMS

To study the effect of parity on impairment of insulin sensitivity during pregnancy and on the risk of gestational diabetes (GDM).

METHODS

We studied the relationship between parity and peripheral insulin sensitivity index (ISI(OGTT)) or GDM in 1880 caucasian women, who underwent a 100-g, 3-h oral glucose tolerance test (OGTT) between the 24th and 28th gestational week and in 75 women who underwent an OGTT in two consecutive pregnancies. A proxy for beta-cell function (basal plasma C peptide/fasting plasma glucose; CP/FPG) was also measured.

RESULTS

By univariate analysis parity was related to decreased ISI(OGTT) and to increased CP/FPG in those with parity > 3 and likewise GDM, diagnosed in 124 women (6.58%), was linearly related to parity (P = 0.0034) and strongly age dependent. The relationships between parity and ISI(OGTT), CP/FPG and GDM were no longer significant after adjustment for age, pregestational body mass index (BMI), and weight gain. GDM was significantly related to age and pregestational weight, while ISI(OGTT) and CP/FPG were inversely related to prepregnancy BMI or weight gain. In comparison with the index pregnancy, the subsequent pregnancy was characterized by an increase in actual and prepregnancy BMI, in 2 h area under curve (AUC) glucose and by a decrease in ISI(OGTT) (P = 0.0001). The longer the time interval between pregnancies and the higher the increment in pregestational BMI or in weight gain during the pregnancy, the greater were the ISI(OGTT) decrease and 2-h AUC glucose increase.

CONCLUSIONS

Parity is not directly linked to insulin sensitivity deterioration, to CP/FPG increase during pregnancy, or to GDM appearance, although it is linked through the mediation of progressive ageing and weight gain either before or during pregnancy, when there is a sufficiently long time interval between pregnancies.

Taurine administration during lactation modifies hippocampal CA1 neurotransmission and behavioural programming in adult male mice

Taurine plays a role in neuronal development. In this study, we examined whether postnatal taurine administration influences the long-term consequences induced by mild neonatal stressors (10 min maternal deprivation plus sham injection, applied daily to neonatal mice up to 21 days). At 30 days of age stressed mice showed higher pain threshold both in the tail-flick--which measures mostly the spinal mechanisms of pain--and in the hot-plate test--which reflects mainly the supraspinal mechanisms of pain. The latter effect was prevented completely by neonatal taurine administration, while the tail-flick test was not affected, thus suggesting that spinal pain is not sensitive to taurine treatment. At 140 days of age, mice which were stressed during the neonatal period showed consistent decrease in immobility time in forced swimming test, and taurine did not influence this parameter. At the same age, the fear/anxiety axis, measured with elevated plus maze test, did not show any consistent changes. Electrophysiological experiments in brain slices obtained from adult mice showed that input-output curves in hippocampal CA1 were increased by taurine administration in lactation. Hence, neonatal administration of taurine might permanently modify the functioning of hippocampus, a brain area which is known to be crucial for learning and memory.

Defective regulation and action of atrial natriuretic peptide in type 2 diabetes

Increased plasma atrial natriuretic peptide (ANP) levels and impaired ANP action have been reported in patients with diabetes or insulin resistance. The aim of this study was to assess the interaction between insulin and ANP in type 2 diabetes. In 12 normotensive, normoalbuminuric type 2 diabetics, we infused insulin at a high (6.6 pmol/min/kg) or, on a different day, at a low rate (0.6 pmol/min/kg) during 4 hours of isoglycemia under isovolumic, isoosmolar conditions. The normal response was established in 12 healthy volunteers using an identical protocol. Despite higher baseline ANP levels (17.7 +/- 2.8 vs. 10.8 +/- 1.8 pg/ml, p = 0.04), urinary sodium excretion was similar in diabetics and controls (113 +/- 8.5 vs. 102 +/- 8.8 mEq/24 hours, p = ns). In both groups, hyperinsulinemia caused a decrease in blood volume (0.33 +/- 0.10 l, p < 0.01), diastolic blood pressure (6 %, p < 0.02), and natriuresis. However, plasma ANP decreased in controls (from 12.7 +/- 1.9 to 8.6 +/- 1.4 pg/ml, p = 0.01) but not in type 2 diabetics (15.1 +/- 2.7 vs. 17.2 +/- 3.8 pg/ml, p = ns). We conclude that ANP release is resistant to volume stimulation in type 2 diabetic patients, and natriuresis is resistant to ANP action. This dual disruption of ANP control may play a role in blood pressure regulation in diabetes.

Platelet antioxidant enzymes in insulin-dependent diabetes mellitus

BACKGROUND

The measurement of the peroxidase scavenging system represented by the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GSH-Px) in blood cells of diabetic patients has, in the past, given equivocal results. Likewise, the role of these intracellular enzymatic scavengers against the oxidative stress of diabetes-associated microangiopathic complications is unknown.

METHODS

Choosing platelets as cell model (as commonly done in previous studies), the aim of this study was to relate the platelet content of SOD, catalase and GSH-Px to the presence of diabetes, as well as to the presence of nephropathy and retinopathy in 35 insulin-dependent diabetic patients, as compared to 10 age-matched control subjects.

RESULTS

The enzymatic activities were not changed in diabetic patients in comparison with healthy controls. After stratifying patients according to presence of nephropathy (24-h urinary albumin excretion rate persistently > or =20 microg min(-1)) or retinopathy, the group of albuminuric patients was characterized by a significant decrease in SOD activity as compared to those in the normoalbuminuric range (4.36+/-1.06 vs. 6.81+/-2.26 mU 10(-9) platelets; p=0.01). Catalase and GSH-Px did not change. No modification in platelet enzyme activities has been found in diabetic subjects with retinopathy.

CONCLUSIONS

These results suggest that diabetic nephropathy, at least in its early stage, may be related to an altered redox state of platelets, as tested by the reduction in SOD activity, thus, indicating that the renal damage in these patients may be associated to a selective increase in platelet susceptibility to variation in the redox state.

Polymorphisms in the hANP (human atrial natriuretic peptide) gene, albuminuria, and hypertension

Atrial natriuretic peptide (ANP) jointly affects kidney function and blood pressure homeostasis and is a candidate susceptibility gene for both essential hypertension and kidney disease. We evaluated the relation between the ScaI and BstXI polymorphisms of the human ANP (hANP) gene, hypertension, and albuminuria in a clinical cohort of 1033 subjects, including type 1 and type 2 diabetic patients, nondiabetic subjects with essential hypertension, and nondiabetic normotensive control subjects. Microalbuminuria was present in 15%, 29%, and 2%, respectively, of type 1 diabetic, type 2 diabetic, and nondiabetic patients. Macroalbuminuria was present in 9% of type 1 diabetics, 21% of type 2 diabetics, and 31% of nondiabetics. Prevalence of hypertension was 31%, 58%, and 61% in normoalbuminuric, microalbuminuric, and macroalbuminuric subjects, respectively (P<0.0001). Genotype distributions were in Hardy-Weinberg equilibrium in all 4 patient subgroups. The frequency of the ScaI mutated allele (A(1)) was significantly lower in hypertensive than in control subjects (11% versus 19%, P=0.018) and in patients with macroalbuminuria (5%) as compared with normoalbuminuric subjects (16%; P<0.0001). In a nominal logistic model adjusting for gender, age, obesity, diabetes, micro/macroalbuminuria, and hypertension, the A(1) allele was independently associated with macroalbuminuria (odds ratio, 0.57; confidence interval, 1.39 to 3.59; P=0.003) but not with hypertension. In the same model, the frequency of the BstXI mutated allele (T(708)) was increased in the presence of microalbuminuria (odds ratio, 2.25; confidence interval, 1.39 to 3.59; P<0.001). We conclude that the mutated genotypes of the ScaI polymorphism are negatively associated with overt nephropathy, whereas the mutated genotypes of BstXI polymorphism are positively associated with microalbuminuria. hANP gene variants may exert a protective effect against the development and progression of kidney damage in diabetes.

Relationship between metabolic glycaemic control and platelet content of glutathione and its related enzymes, in insulin-dependent diabetes mellitus

The relationship between glycaemic metabolic control and intracellular concentration of reduced glutathione (GSH) and related enzymes GSH-peroxidase (GSH-Px), GSH-reductase (GSH-Red), GSH-transferase (GSH-Tr), glucose-6-P-dehydrogenase (G6PDH), and thioltransferase (TT) in patients with insulin-dependent diabetes mellitus (IDDM) is controversial. Choosing platelets as cell model (as commonly done in previous studies), the aim of this study was to relate the platelet content of GSH and related enzymes to glycaemic metabolic control, expressed as glycated haemoglobin (HbA1c), as well as to presence of retinopathy and nephropathy in 114 IDDM patients. As compared to controls, both GSH and GSH-Red (geometric means (95% CI)) were significantly increased in platelets of diabetic patients: 3.3 (0.7-9.6) vs. 2.4 (0.8-7.6) mmol 10(-9) platelets; P=0.01 for GSH, and 30.6 (14.7-61.6) vs. 22.2 (8.7-52.2) mU 10(-9) platelets, P=0.0002 for GSH-Red, and TT activity was marginally decreased in the IDDM group (P=0.06). While no clear relationship was present between GSH-related enzymes and HbA1c, a trend was present toward a non-linear relation between HbA1c and GSH, being significantly related by a parabolic curve (P=0.002). As compared to patients with normoalbuminuria (n=88), diabetic patients with increased urinary albumin excretion rate (n=26) had a significant decrease in platelet TT concentration (3.2 (0.9-6.7) vs. 5.1 (1.9-18.7) mU 10(-9) platelets; P=0.0002), whereas retinopathy was not associated to modifications in GSH or in the enzymatic pattern. In summary: (a) platelet GSH and GSH-Red are increased in IDDM, while other enzymes are unmodified; (b) GSH seems to be related to metabolic control according to non-linear parabolic curve; (c) presence of increased albuminuria is associated to a selective decrease in platelet TT content.

Insulin: new roles for an ancient hormone

Recent research has greatly expanded the domain of insulin action. The classical action of insulin is the control of glucose metabolism through the dual feedback loop linking plasma insulin with plasma glucose concentrations. This canon has been revised to incorporate the impact of insulin resistance or insulin deficiency, both of which alter glucose homeostasis through maladaptive responses (namely, chronic hyperinsulinaemia and glucose toxicity). A large body of knowledge is available on the physiology, cellular biology and molecular genetics of insulin action on glucose production and uptake. More recently, a number of newer actions of insulin have been delineated from in vitro and in vivo studies. In sensitive individuals, insulin inhibits lipolysis and platelet aggregation. In the presence of insulin resistance, dyslipidaemia, hyper-aggregation and anti-fibrinolysis may create a pro-thrombotic milieu. Preliminary evidence indicates that hyperinsulinaemia per se may be pro-oxidant both in vitro and in vivo. Insulin plays a role in mediating diet-induced thermogenesis, and insulin resistance may therefore be implicated in the defective thermogenesis of diabetes. In the kidney, insulin spares sodium and uric acid from excretion; in chronic hyperinsulinaemic states, these effects may contribute to high blood pressure and hyperuricaemia. Insulin hyperpolarises the plasma membranes of both excitable and non-excitable tissues, with consequences ranging from baroreceptor desensitisation to cardiac refractoriness (prolongation of QT interval). Under some circumstances insulin is vasodilatory-the mechanism involving both the sodium-potassium pump and intracellular calcium transients. Finally, by crossing the blood-brain barrier insulin exerts a host a central effects (sympatho-excitation, vagal withdrawal, stimulation of corticotropin releasing factor), collectively resembling a stress reaction. Description and understanding of these new roles, their interactions, the interplay between insulin resistance and hyperinsulinaemia, and their implications for cardiovascular disease have only begun.

Respiratory muscle function and hypoxic ventilatory control in patients with type I diabetes

STUDY OBJECTIVES

The interaction among pulmonary mechanics, respiratory muscle performance, and ventilatory control in subjects with insulin-dependent diabetes mellitus has so far received little attention. We therefore decided to assess the role of central factors and peripheral factors on the ventilatory response to a hypoxic stimulus in type I diabetic patients.

SUBJECTS

Eight patients in stable condition aged 19 to 48 years old, with insulin-dependent diabetes mellitus (duration of the disease, 36 to 240 months) and no history of smoking, cardiopulmonary involvement, or autonomic neuropathy; and an age- and gender-matched control group.

MEASUREMENTS

In each patient, we measured the following: pulmonary volumes; diffusing capacity of the lung for carbon monoxide (D(LCO)); time and volume components of ventilation (tidal volume [V(T)] and respiratory frequency); static compliance (Clstat) and dynamic compliance (Cldyn); swings in pleural pressure (Pes) and gastric pressure (Pg); and transdiaphragmatic pressure (Pdi), obtained by subtracting Pes from Pg. Maximal inspiratory Pes and Pdi during a maximal sniff maneuver were also measured. Swings in Pes and Pdi during V(T) as a percentage of Pes and Pdi during the maximal sniff maneuver [Pessw(%Pessn) and Pdisw(%Pdisn), respectively] were both considered as a measure of central respiratory output, and the Pessw(%Pessn)/V(T) ratio was considered as an index of neuroventilatory dissociation (NVD) of the inspiratory pump. Subjects were studied at baseline and during hypoxic rebreathing.

RESULTS

Pulmonary volumes and D(LCO) were normal or slightly reduced. A lower Cldyn, higher central respiratory output, and NVD were found. During hypoxic rebreathing, patients had lower V(T), similar central respiratory output, and greater NVD per unit change in arterial oxygen saturation compared with values in control subjects. An increase in dynamic elastance, computed as 1/Cldyn, during hypoxia was found in patients, but not in normal subjects, and was directly related to concurrent changes in NVD.

CONCLUSIONS

We have shown that the assessment of a normal Clstat and normal routine parameters of airway obstruction does not permit the definite exclusion of the role of peripheral airway involvement in insulin-dependent diabetes mellitus. Peripheral airway involvement is likely to influence indices of hypoxic ventilator) drive by modulating a normal central motor output into a rapid and shallow pattern of ventilatory response.

Dyspnoea, peripheral airway involvement and respiratory muscle effort in patients with type I diabetes mellitus under good metabolic control

Dyspnoea and pulmonary dysfunction have recently been associated with Type I (insulin-dependent) diabetes mellitus. The putative role of altered pulmonary mechanics and of performance of inspiratory muscles in inducing dyspnoea has not been yet assessed in Type I diabetes. To better focus on this topic we evaluated nine patients with Type I diabetes mellitus, aged 19 to 48 years with good and stable metabolic control, without a history of smoking and microvascular complications, alongside a group of 14 healthy control subjects. In each subject, pulmonary volumes, static and dynamic compliance, pleural pressure swings (Pplsw), maximal inspiratory pressures (Pplsn), Pplsw(%Pplsn), a measure of respiratory muscle effort, and tension-time index [TTI=TI/TTOTxPplsw(%Pplsn)] were measured (TI=inspiratory time;TTOT=total time of the respiratory cycle). All subjects were studied at baseline and during hypoxic rebreathing. Patients had normal pulmonary volumes. During hypoxic rebreathing, a normal change in respiratory muscle effort [DeltaPplsw(%Pplsn)/DeltaSaO2] and DeltaTTI/DeltaSaO2, and a lower change in tidal volume versus change in oxygen saturation [DeltaVT(% vital capacity)/DeltaSaO2], resulted in a higher ratio of respiratory effort to tidal volume [Pplsw(%Pplsn)/VT(% vital capacity)], a measure of neuroventilatory dissociation of the respiratory pump. Hypoxic dyspnoea, assessed by a modified Borg scale, showed a greater rate of rise (DeltaBorg/DeltaSaO2) and a greater increase for a given level of respiratory effort in patients. Moreover, neuroventilatory dissociation related to the expression of peripheral airway involvement, as assessed in terms of low dynamic compliance, and to concurrent change in dyspnoea sensation. Patients with Type I diabetes mellitus under good metabolic control and with normal lung volumes may have abnormal peripheral airway function. The latter is thought to be responsible for the association between dyspnoea sensation and neuroventilatory dissociation.

Plasma and platelet ascorbate pools and lipid peroxidation in insulin-dependent diabetes mellitus

BACKGROUND

As diabetes mellitus represents a situation in which production of peroxides is increased, the aim of this study was to investigate the relationship between plasma and platelet levels of ascorbic acid (AA)/dehydroascorbic acid (DHA) and those of malonyldialdehyde (MDA), an indirect marker of lipoperoxides, both assayed using high-performance liquid chromatography (HPLC), in 59 patients with insulin-dependent diabetes mellitus (IDDM) compared with 51 healthy control subjects matched for sex, age, smoking habits, as well as for dietary intake of energy, alcohol and vitamin C.

RESULTS

Mean plasma and platelet MDA were significantly higher in the patients affected with IDDM than in control subjects. Moreover, the diabetic group was characterized by a huge decrease in plasma AA [8.45 +/- 5.5 mumol L-1 (SD) vs. 33.4 +/- 7.6 mumol L-1, P = 0.0001], mirrored by a significant increase in plasma DHA (11.9 +/- 3.9 mumol L-1 vs. 3.9 +/- 2.5 mumol L-1, P = 0.0001). No detectable DHA was observed in the platelets from both diabetic and control subjects, whereas AA was significantly increased in platelets from diabetic patients compared with control subjects (42.6 +/- 7.4 vs. 34.8 +/- 5.1 nmol 10(-9) platelets, P = 0.0001). Platelet AA in the diabetic group was significantly inversely correlated with glycated haemoglobin (r = -0.34; P = 0.04) and directly with plasma AA (r = 0.39; P = 0.02), the sum of plasma AA + DHA (r = 0.44; P = 0.009) and with platelet MDA (r = 0.38; P = 0.02).

CONCLUSION

(a) The ratio plasma AA/DHA is significantly lowered in IDDM in association with an increase in MDA levels; (b) only AA is detected in platelets, being augmented in the diabetic group; (c) plasma ascorbate depletion does not reflect platelet levels of AA; and, finally, (d) metabolic control, as well as intracellular lipoperoxides, modulates platelet AA in IDDM.

Further insights into the anti-aggregating activity of NMDA in human platelets

1. In the present study the effect of N-methyl-D-aspartate (NMDA) on thromboxane B2 synthesis and on [Ca2+]i was studied in human platelets. 2. NMDA (10(-7) M) completely inhibited the synthesis of thromboxane B2 from exogenous arachidonic acid (AA), while it did not interfere with the aggregating effect of the thromboxane A2 receptor agonist U-46619. 3. NMDA (0.1 microM - 10 microM) dose-dependently increased intracellular calcium in washed platelets preloaded with fura 2 AM, and this effect was not additive with that of AA. 4. NMDA shifted the dose-response curve of AA to the right. At the highest AA concentrations platelet aggregation was not inhibited. 5. The antiaggregating effect of NMDA was not antagonized by N(G)-monomethyl-L-arginine (L-NMMA), a nitric oxide synthase (NOS) inhibitor. 6. Finally, NMDA (0.01 nM - 100 nM) associated with either aspirin or indomethacin significantly potentiated the antiaggregating activity of both cyclo-oxygenase inhibitors. 7. It was concluded that NMDA is a potent inhibitor of platelet aggregation and thromboxane B2 synthesis in human platelet rich plasma (PRP).

Effects of troglitazone on insulin action and cardiovascular risk factors in patients with non-insulin-dependent diabetes

OBJECTIVE

Insulin resistance is a potential target for pharmacologic intervention in non-insulin-dependent diabetes. Troglitazone is being evaluated as an insulin enhancer in insulin resistant states.

RESEARCH DESIGN AND METHODS

We randomized 40 patients with non-insulin-dependent diabetes to diet plus placebo (n = 15) or diet plus troglitazone (n = 25; 200 mg/day) treatment for 8 weeks. Fasting endogenous glucose production (EGP, by the stable isotope technique) and whole-body insulin sensitivity (by the insulin suppression test) were measured at baseline and on days 3, 7, 14, 28, and 56 of treatment.

RESULTS

By day 56, fasting plasma glucose had risen from 12.0 +/- 0.9 to 12.8 +/- 1.2 mmol/L in the placebo group and had fallen from 12.4 +/- 0.6 to 11.3 +/- 0.6 mmol/L in the troglitazone group (p = 0.03). This was the result of small improvements in whole-body insulin sensitivity (steady-state plasma glucose during the insulin suppression test: from 11.09 +/- 1.1 to 10.3 +/- 0.8 mmol/L versus 13.8 +/- 1.0 to 10.0 +/- 0.9 mmol/L, placebo versus troglitazone; p = 0.01) and EGP (from 103% +/- 3% versus 96% +/- 2% of baseline, placebo versus troglitazone; p = 0.09). The time course of insulin action showed an early (first week of treatment) decrease in EGP in the troglitazone group that was maintained throughout, whereas steady-state plasma glucose levels began to diverge toward the end of treatment. The effects of insulin on plasma free fatty acid and potassium concentrations were not different between placebo and troglitazone. The cardiovascular risk profile (heart rate; serum triglycerides; total, low-density lipoprotein, and high-density lipoprotein cholesterol; proinsulin; uric acid; plasminogen activator inhibitor-1 antigen and activity; 24-hour blood pressure monitoring and urinary albumin excretion) was unaltered by troglitazone treatment.

CONCLUSIONS

Troglitazone as monotherapy for typical non-insulin-dependent diabetes had a modest anti-hyperglycemic effect and, at the dose used in this study, had no effect on cardiovascular risk factors.

Raised erythrocyte polyamine levels in non-insulin-dependent diabetes mellitus with great vessel disease and albuminuria

Erythrocyte content of polyamines has been previously found increased in insulin-dependent diabetes mellitus with microalbuminuria. Since increased urinary albumin excretion (AER) is associated with the presence of vascular diseases in non-insulin-dependent diabetes mellitus (NIDDM) the aim of this study was to verify the hypothesis that the presence of increased urinary albumin excretion (AER), and of macroangiopathy in NIDDM would be related to a significant modification in polyamine erythrocyte levels. The erythrocyte content of spermine and spermidine was measured by a HPLC method in 39 patients affected with NIDDM and in 24 age- and sex-matched healthy control subjects, evaluating the relationship between erythrocyte polyamines of NIDDM patients with the presence of macroangiopathy as well as with retinopathy or increased AER (> or = 20 micrograms/ml). Both spermidine and spermine were not modified in the group of NIDDM patients while the presence of raised urinary AER was characterised by an increase in erythrocyte spermine (11 +/- 1.7 vs. 7.7 +/- 1.7 nmol/ml packed erythrocytes; P = 0.04) and spermidine (18.9 +/- 1.7 vs. 12.6 +/- 1.5 nmol/ml packed erythrocytes; P = 0.02), being both polyamines significantly related to AER and to metabolic control. Erythrocyte spermidine and spermine were moreover significantly higher in the group of patients with macroangiopathy (22.8 +/- 1.5 vs. 12.3 +/- 1.5 nmol/ml; P = 0.0001 and 11.5 +/- 1.7 vs. 7.8 +/- 1.7 nmol/l packed erythrocytes; P = 0.04) and being, moreover, erythrocyte spermidine augmented in patients with retinopathy (24.2 +/- 1.5 vs. 12.2 +/- 1.5 nmol/ml packed erythrocytes; P = 0.009). In conclusion the levels of erythrocyte spermine and spermidine are both associated with the presence of albuminuria and macroangiopathy in NIDDM, while spermidine is on the average increased in the group of diabetic patients with retinopathy.

Reciprocal association between insulin sensitivity and the haematocrit in man

In epidemiological studies, a high haematocrit has been associated both with increased cardiovascular risk and with hyperinsulinaemia, a surrogate of insulin resistance. To examine directly the relationship between the haematocrit and insulin sensitivity, we studied 12 healthy volunteers and 12 patients with non-insulin-dependent diabetes mellitus (NIDDM) with the use of a 4-hour hyperinsulinaemic [1 mU min-1 kg-1] isoglycaemic clamp. In the whole group, insulin sensitivity (as the ratio of insulin-mediated glucose clearance to steady-state plasma insulin concentrations) was inversely related to the haematocrit (r = 0.50, P < 0.01). To test whether acute changes in the haematocrit affect insulin sensitivity, in two NIDDM patients and three healthy subjects the clamp study was repeated after lowering (-18%) the haematocrit by erythro-apheresis. In all five subjects, the lower haematocrit was associated with slightly reduced (-7% on average, P = NS) rather than increased insulin sensitivity. We conclude that insulin sensitivity is inversely related to the haematocrit independently of the glucose tolerance status. The association does not result from acute haemodynamic effects on insulin sensitivity, and may therefore reflect an action of insulin resistance/ hyperinsulinaemia on blood viscosity, or the presence of a common determinant.

Effect of insulin on systemic and renal handling of albumin in nondiabetic and NIDDM subjects

Insulin resistance and hyperinsulinemia cluster with microalbuminuria in both diabetic and nondiabetic subjects, but the mechanism underlying this association is unknown. To test the hypothesis that insulin influences protein permeability, we measured the albumin transcapillary escape rate (TER) by the (131)I-labeled albumin technique in 12 healthy volunteers and 12 normoalbuminuric NIDDM patients (fasting plasma glucose, 10.9 +/- 1.3 mmol/l) during 4 h of isoglycemia with high (1.1 mU x min(-1) x kg(-1)) or, on a different day, low (0.1 mU x min(-1) x kg(-1)) insulin infusion. In both patients and control subjects, high insulin was associated with a 7% decrease in blood volume (P = 0.006) and a 6% decrease in diastolic blood pressure (P < 0.02), these two changes being related to one another (r = 0.56, P < 0.01). Basal albumin TER was similar in patients (8.4 +/- 0.5% x h(-1)) and control subjects (7.7 +/- 0.7% x h(-1)) and was not significantly changed by high insulin in either group (patients vs. control subjects, 7.3 +/- 0.9 vs. 6.2 +/- 0.4% x h(-1); NS vs. low insulin). In contrast, high insulin increased renal albumin excretion (from 3.6 +/- 0.8 to 5.4 +/- 1.1 microg/min, P < 0.01) and clearance rate (0.09 +/- 0.02 to 0.13 +/- 0.03 microl/min, P < 0.001) in patients but not in control subjects. To localize the effect of insulin along the nephron, we measured the urinary excretion of N-acetyl-beta-D-glucosaminidase (beta-NAG), released by the proximal tubule; retinol-binding protein (RBP), reabsorbed by the proximal tubule; and Tamm-Horsfall protein (THP) and epidermal growth factor (EGF), both secreted by the distal tubule. For both beta-NAG and RBP, but not EGF or THP, insulin enhanced urinary excretion (diabetics vs. controls: beta-NAG, 0.48 vs. -0.15 microU/min [P = 0.03]; RBP, 78 vs. -32 ng/min [P = 0.05]). In conclusion, physiological hyperinsulinemia does not affect systemic albumin permeability in healthy subjects or normoalbuminuric NIDDM patients. In contrast, in NIDDM patients, but not in healthy subjects, insulin increases the urinary excretion of albumin and protein markers of proximal tubular function. The significance of this finding for the pathogenesis of diabetic nephropathy remains to be established.

Effect of a reduced-fat diet with or without pravastatin on glucose tolerance and insulin sensitivity in patients with primary hypercholesterolemia

Pharmacological treatment of hyperlipidemia may be associated with deterioration of glucose tolerance. We randomized 20 nonobese patients with primary familial hypercholesterolemia (serum total cholesterol 7.8 +/- 0.4 mM, triglycerides 1.4 +/- 0.2 mM) to an isocaloric, reduced fat (< 30%) low-cholesterol (200 mg/day) diet with placebo or pravastatin (40 mg/day). Oral glucose tolerance, endogenous insulin response to glucose, insulin sensitivity (determined by the euglycemic insulin clamp technique), hepatic glucose production (by the tritiated glucose technique), and substrate utilization (by indirect calorimetry) were measured at baseline and after 8 weeks of treatment. Ten normocholesterolemic healthy subjects, matched to the patients by age, sex, and body weight, served as the control group. Diet alone (with no change in body weight) was associated with a significant 15% decrease in both serum low density lipoprotein (LDL)-cholesterol and triglycerides (p < 0.001 for both), and a slight decrease in high density lipoprotein (HDL)-cholesterol concentrations, paralleled by reductions in Apo B, C2, C3, and E levels (p < 0.05 or less). The addition of pravastatin led to a significantly larger reduction in LDL-cholesterol (30%, p < 0.05) and an 8% increase (p < 0.02) in total HDL-cholesterol concentrations. Accordingly, the ratio of LDL:HDL cholesterol (which was 60% higher than in controls at baseline) remained unchanged in the placebo-diet group whereas it was restored to normal in the pravastatin-diet group. Glucose tolerance, insulin response, insulin-induced inhibition of hepatic glucose production and lipolysis, and insulin-mediated glucose uptake and oxidation were all slightly but not significantly improved after treatment, with no significant differences between pravastatin and placebo. In nonobese patients with primary hypercholesterolemia, pravastatin treatment in combination with an isocaloric, reduced-fat diet leads to a marked reduction in LDL-cholesterol and triglycerides levels and a normalization of the LDL:HDL ratio without affecting glucose tolerance or insulin sensitivity.

Glutathione, glutathione utilizing enzymes and thioltransferase in platelets of insulin-dependent diabetic patients: relation with platelet aggregation and with microangiopatic complications

Reduced glutathione (GSH) and activity of GSH related enzymes play a key role in defence against oxygen free radicals, whose production is, as known, raised in patients affected by diabetes mellitus, and at the same time they may contribute to the process of platelet aggregation. The purpose of this study was to evaluate GSH levels and activity of glutathione peroxidase (GSH-Px), glutathione reductase (GSSG-Red), glutathione transferase (GSH-Tr), glucose-6-phosphate-dehydrogenase (G6PDH), and thioltransferase (TT) in platelets of insulin-dependent diabetic patients in fair metabolic control (mean glycated haemoglobin: 6.5%), as related to presence of retinopathy, neuropathy or nephropathy and to platelet aggregation by arachidonic acid (AA) in vitro. Mean effective dose (ED50) of AA was on average significantly lower in the group of insulin-dependent diabetic patients (0.41 +/- 0.02 mM (SEM), n = 46) as compared with that of control subjects strictly matched for age, sex and weight (0.77 +/- 0.02, n = 51; P = 0.0001). Mean platelet GSH as well as the activity of GSH related enzymes expressed as geometric mean (95% confidence intervals) were similar in diabetic patients and in controls, except for GSSG-Red whose activity was significantly higher in diabetic subjects (28.5 (14.4-57.5) mU 10(-9) platelets vs. 20.3 (8.7-56) mU 10(-9) platelets; P = 0.01). In the diabetic group TT was reduced when compared with healthy controls (3.8 (0.9-12.2) mU 10(-9) platelets vs. 6 (1.6-26.1) mU 10(-9) platelets; P = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma and platelet taurine are reduced in subjects with insulin-dependent diabetes mellitus: effects of taurine supplementation

Plasma and platelet taurine concentrations were assayed in 39 patients with insulin-dependent diabetes mellitus (IDDM) and in 34 control subjects matched for age, sex, and both total and protein-derived daily energy intake. Platelet aggregation induced by arachidonic acid in vitro at baseline and after oral taurine supplementation (1.5 g/d) for 90 d was also studied. Plasma and platelet taurine concentrations (mean +/- SEM) were lower in diabetic patients (65.6 +/- 3.1 mumol/L, or 0.66 +/- 0.07 mol/g protein) than in control subjects (93.3 +/- 6.3 mumol/L, or 0.99 +/- 0.16 mol/g protein, P < 0.01). After oral supplementation, both plasma and platelet taurine concentrations increased significantly in the diabetic patients, reaching the mean values of healthy control subjects. The effective dose (mean +/- SEM) of arachidonic acid required for platelets to aggregate was significantly lower in diabetic patients than in control subjects (0.44 +/- 0.07 mmol compared with 0.77 +/- 0.02 mmol, P < 0.001, whereas after taurine supplementation it equaled the mean value for healthy control subjects (0.72 +/- 0.04 mmol). In in vitro experiments, taurine reduced platelet aggregation in diabetic patients in a dose-dependent manner, whereas 10 mmol taurine/L did not modify aggregation in healthy subjects.

Indications of reduced pulmonary function in type 1 (insulin-dependent) diabetes mellitus

Abnormalities of pulmonary function tests have been described in type 1 (insulin-dependent) diabetes mellitus (IDDM). To better characterise such abnormalities and to verify whether these latter are associated with the presence of diabetic microvascular disease we compared 23 non-smoking patients who had IDDM with 24 non-smoking healthy control subjects strictly matched for sex, age, and body mass index. Compared with controls, diabetic patients had a reduced forced vital capacity (FVC) (87.5 +/- 13.1% vs. 96.4 +/- 13.6% of the predicted; P = 0.03) and forced expiratory volume in 1 s (FEV1) (90.5 +/- 17.7% vs. 101.2 +/- 13.2% of the predicted; P = 0.02). While within the group of patients the presence of retinopathy and autonomic neuropathy were not associated with modifications of pulmonary function tests, those with altered urinary albumin excretion rate (AER > or = 20 micrograms/min; range 21-589) (n = 7) had a significantly lower pulmonary diffusion capacity (DLCO) than the 16 normoalbuminuric subjects (62.6 +/- 7.2% vs. 88.7 +/- 20.1% of the predicted; P = 0.01). Moreover, in the group of patients, DLCO was inversely related with AER (r = -0.43; P = 0.04). In conclusion, IDDM is characterised by reduced FVC and FEV1, while a significant decrease in DLCO may be considered as selectively associated with renal disease.

Effect of chronic ACE inhibition on glucose tolerance and insulin sensitivity in hypertensive type 2 diabetic patients

We studied 14 moderately overweight Type 2 diabetic patients with essential hypertension in stable metabolic control after a run-in period, and again after 3 months of antihypertensive treatment with the angiotensin-converting enzyme (ACE) inhibitor captopril. Glucose tolerance was tested with a 75g oral glucose load (OGTT) and insulin sensitivity was measured by the insulin suppression test (IST) while dietary and drug treatment of the hyperglycemia was maintained constant. In the whole group, mean blood pressure (MBP) fell progressively over 3 months from a baseline value of 123 +/- 3 mmHg (1 mmHg = 0.133 kpa) to a final value of 115 +/- 2 mmHg (P < 0.005). After treatment, fasting plasma glucose, insulin, free fatty acid (FFA), potassium, and glycosylated hemoglobin concentrations were unchanged from baseline. There were no significant differences in glucose tolerance and insulin sensitivity between pre- and post-treatment values. Neither endogenous (oral glucose) nor exogenous (IST) insulin caused any change in plasma potassium concentration. This resistance to the hypokalemic action of insulin was not affected by captopril.

Pityriasis rubra pilaris, lichen planus, alopecia universalis and vitiligo in a patient with chronic viral hepatitis C

A 43-year-old man, affected with alopecia universalis and vitiligo since his childhood, developed erythrodermic pityriasis rubra pilaris followed then by lichen planus; chronic viral hepatitis C was diagnosed. This appears to be a unique constellation of cutaneous diseases implying both autoimmunity and hepatitis C virus.

Relation of birthweight to maternal plasma glucose and insulin concentrations during normal pregnancy

Maternal diabetes mellitus is complicated by fetal macrosomia and predisposes the offspring to diabetes, but recent evidence indicates that a low, not high, birthweight is associated with a higher incidence of Type 2 (non-insulin dependent) diabetes in adult life. To clarify the relationships between maternal glucose and insulin levels and birthweight, we measured oral glucose tolerance and neonatal weight in a large group (n = 529) of women during the 26th week of pregnancy. Women with gestational diabetes (n = 17) had more familial diabetes, higher pre-pregnancy body weight, and tended to have large-for-gestational-age babies. In contrast, women with essential hypertension (n = 10) gave birth to significantly (p < 0.01) smaller babies. In the normal group (without gestational diabetes or hypertension, n = 503), maternal body weight before pregnancy and at term, maternal height, week of delivery, gender of the newborn, and parity were all significant, independent predictors of birthweight, together explaining 23% of the variability of neonatal weight. In addition, both fasting (p < 0.006) and 2-h post-glucose (p = 0.03) maternal plasma glucose concentrations were positively associated with birthweight independent of the other physiological determinants, accounting, however, for only 10% of the explained variability. In a subgroup of 134 normal mothers with pre-pregnancy body mass index of less than 25 kg.m-2, in whom plasma insulin measurements were available, the insulin area-under-curve was inversely related to birthweight (p < 0.02) after simultaneously adjusting for physiological factors and glucose area.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of chronic ACE inhibition on glucose tolerance and insulin sensitivity in hypertensive type 2 diabetic patients

The question, of whether long-term treatment of essential hypertension with angiotensin-converting enzyme (ACE) inhibitors is capable of modifying glucose tolerance or insulin sensitivity in Type 2 (non-insulin dependent) diabetes, is still unsolved. We studied 14 moderately overweight Type 2 diabetic patients with essential hypertension in stable metabolic control after a run-in period and again after 3 months of antihypertensive treatment with the ACE inhibitor, captopril. Glucose tolerance was tested with a 75-g oral glucose load and insulin sensitivity was measured by the insulin suppression test, while dietary and drug treatment of the diabetes remained constant. In the whole group, mean blood pressure (MBP) fell progressively over 3 months from a baseline value of 123 +/- 3 mmHg to a final value of 115 +/- 2 mmHg (p < 0.005); in six patients, the change in MBP was < 5 mmHg (non-responders), thus giving a clinical response rate of approximately 60%. After treatment, fasting plasma glucose, insulin, free fatty acid (FFA), potassium, and glycated haemoglobin concentrations were unchanged from baseline. During the oral glucose tolerance test, the incremental glucose area-under-curve was 0.75 +/- 0.05 mol 120 min l-1 before and 0.76 +/- 0.06 mol 120 min l-1 after treatment (p = ns). Endogenous insulin response and suppression of plasma FFA levels were superimposable on the two occasions. During the insulin suppression test, steady-state plasma glucose levels were 14.4 +/- 1.3 vs 14.2 +/- 1.1 mmol l-1 before and after chronic ACE inhibition, respectively, at comparable hyperinsulinaemic plateaux (291 +/- 21 vs 287 +/- 14 pmol l-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte spermidine levels in IDDM patients

OBJECTIVES

To evaluate whether erythrocyte levels of polyamines spermidine and spermine (expressed in nmol/ml packed erythrocytes [PRBCs]) are modified in insulin-dependent diabetes mellitus (IDDM) and are associated with the presence of retinopathy or nephropathy.

RESEARCH DESIGN AND METHODS

We studied erythrocyte spermidine and spermine levels in 38 IDDM patients with or without persistent microalbuminuria (urinary albumin excretion rate [AER] between 20 and 200 micrograms/min), macroalbuminuria (AER greater than 200 micrograms/min), or retinopathy compared with 60 sex- and age-matched control subjects.

RESULTS

Mean +/- SD erythrocyte spermine content was similar in both diabetic (9.7 +/- 5.5 nmol/ml PRBCs) and control (8.8 +/- 3.5 nmol/ml PRBCs) subjects, whereas spermidine was higher in diabetic (19.1 +/- 7.2 nmol/ml PRBCs) than in control (14.5 +/- 4 nmol/ml PRBCs, P = 0.0007) subjects. Moreover, spermidine was significantly higher in the groups with microalbuminuria (n = 11, 22.5 +/- 9.2 nmol/ml PRBCs) and macroalbuminuria (n = 4, 22.2 +/- 5.7 nmol/ml PRBCs) than in both normoalbuminuric (n = 23, 16.9 +/- 5.6 nmol/ml PRBCs) and control (F = 9.78, P = 0.0001) subjects, and correlated with log AER (r = 0.41, P = 0.009). Similarly, proliferative retinopathy was associated with a significant increase in spermidine (n = 5, 20 +/- 7 nmol/ml PRBCs compared with control subjects [P = 0.0009]).

CONCLUSIONS

Our data suggest that erythrocyte spermidine content is increased in IDDM patients associated with both diabetic nephropathy and advanced retinopathy.

Bilateral segmental neurofibromatosis

Neurofibromatosis (NF) is a heterogeneous disorder clinically characterized by the presence of neurofibromas, multiple café au lait spots, intertriginous freckles and Lisch nodules. We describe an unusual case of NF with cutaneous neurofibromas localized on the anterior chest, in a bilateral dermatomal distribution. No other signs were detected. The family history was negative for NF. The different subsets of NF are briefly discussed, with particular emphasis on the segmental type.

Relation between urinary albumin excretion and skin involvement in patients with psoriasis

The increase in urinary albumin excretion rate (AER), a hallmark of both diabetic nephropathy and hypertension, has also been described in patients affected with diffuse psoriasis. The aim of this study was to investigate whether such an increase is independent of the coexistence of diabetes or hypertension and whether it may be related to the extension and severity of skin lesions. Median AER, determined by radioimmunoassay, was significantly higher in a group of 32 normotensive nondiabetic psoriatic patients than in 36 age- and sex-matched controls (9.6 vs. 5.3 micrograms/min; p = 0.0006). AER was related with grading of skin involvement (r = 0.65; p = 0.001); patients with the most widespread skin lesions (psoriasis area and severity index: PASI greater than 11) were characterized by a significantly raised median AER (14.9 micrograms/min) compared with those with PASI scores between 4 and 11 (9.8 micrograms/min) or less (5.6 micrograms/min) and controls (F = 10.58; p = 0.0001), independent of other covariates such as age, sex and blood pressure (p = 0.001). This latter finding was confirmed by the prevalence of microalbuminuria (AER greater than 10 micrograms/min) which was present in 2 out of 8 patients with PASI less than 4, 0 out of 12 patients with PASI ranging between 4 and 11 and in 5 out of 12 psoriatics with PASI greater than 11 (p = 0.038 by two-tailed Fisher's exact test).

Liquid oxygen contaminants--increase in concentration during use of domiciliary liquid oxygen medical systems

The quality of liquid oxygen in domiciliary medical systems used for oxygen therapy was investigated during the emptying cycle under simulated breathing conditions. The increase in the levels of contaminants during the use of these systems was evaluated by gas chromatography and two sampling methods. The quality of liquid oxygen from storage tanks located in hospitals and in the production or in distribution plants was also investigated.

Serum lipids and lipoproteins in type 2 diabetic patients with persistent microalbuminuria

To investigate whether persistent microalbuminuria is related to altered levels of both lipids and apolipoproteins in Type 2 diabetes mellitus serum total-cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, apolipoprotein A-I, and apolipoprotein B were measured by standard methods in a group of Type 2 diabetic patients affected by persistent microalbuminuria (albumin excretion rate (AER) 20-200 micrograms min-1) as compared with a group of sex- and age-matched non-microalbuminuric patients (AER less than 20 micrograms min-1). The groups were stratified according to a short (less than or equal to 5 years) or a longer (greater than 5 years) duration of diagnosed diabetes. Microalbuminuria was not associated with significant changes of serum total-cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol, and apolipoproteins in the group of patients with a duration of disease greater than 5 years, while microalbuminuric patients less than or equal to 5 years from diagnosis (n = 11) had serum total-cholesterol, triglycerides, LDL-cholesterol, and apoprotein B higher than non-microalbuminuric control patients (n = 26) (cholesterol 6.2 +/- 0.9 vs 5.1 +/- 1.0 mmol l-1 (p = 0.003); triglycerides 2.1 +/- 0.7 vs 1.7 +/- 1.3 mmol l-1 (p = 0.03); LDL-cholesterol 4.1 +/- 0.8 vs 3.0 +/- 0.7 mmol l-1 (p less than 0.001); apo-B 1.3 +/- 0.3 vs 1.1 +/- 0.3 g l-1 (p = 0.02). In these patients with shorter duration of diabetes many of the serum lipid measures correlated positively with AER.

Serum spermidine oxidase activity in patients with insulin-dependent diabetes mellitus and microvascular complications

Metabolism of polyamines (spermidine and spermine) is known to be strictly related to the growth processes of eukaryotic cells. Since cell replication processes appear altered in insulin-dependent diabetes mellitus (IDDM), especially when associated with its microvascular complications, the aim of this study was measuring serum spermidine oxidase activity (SOA), a key enzyme in the metabolic pathway of polyamines, in 47 patients with IDDM as compared with 63 healthy control subjects matched for age and sex. Mean SOA levels +/- SD were significantly lower in IDDM patients (177.4 +/- 57.2 mu kat/l) than in controls (247.6 +/- 68.1 mu kat/l; p less than 0.001), being SOA inversely related with daily insulin dose. SOA was moreover significantly higher (but similar to controls) in the group with increased urinary albumin excretion rate (AER persistently greater than 20 micrograms/min); (n = 17; 213.1 +/- 62.6 mu kat/l) in comparison with normoalbuminuric subjects (n = 30; 156.6 +/- 43.5 mu kat/l; F = 21.78; p = 0.0001). SOA was correlated with AER (r = 0.45; p = 0.001), independently of age, duration of disease, serum creatinine, body weight, blood pressure and metabolic control, as shown by a multiple regression analysis model (p = 0.003). Presence of background retinopathy was not associated with modified levels of SOA, which was conversely higher, although not significantly, in the patients with proliferative retinal lesions. In conclusion serum SOA is deeply altered in IDDM patients, being markedly reduced in the whole group of patients and conversely independently increased up to the mean values of controls in presence of increased AER or advanced retinopathy.

Serum digoxin and beta-methyldigoxin in elderly patients on hospital admission: correlation with home compliance and clinical variables

Serum digoxin and beta-methyldigoxin (BMD) were measured in 165 elderly patients (age greater than 60 years) admitted to hospital, of whom 109 had been treated at home with digoxin and 56 with BMD. The mean BMD level was significantly lower than that of digoxin (1.1 vs. 1.4 ng/ml). Creatinine clearance and daily dose were the variables most strongly associated with digoxin level, and the prescribed dose and serum albumin were the best predictors of the BMD concentration. Compliance was assessed by a compliance index (CI), namely the ratio of the measured glycoside concentration, corrected for creatinine clearance, over the expected steady-state dose, calculated from a hospitalized reference group. Compliant individuals in both treatment groups, i.e. those with a CI greater than the median value, were characterized by a lower daily dose and dosage frequency. Toxicity, whether clinical or electrocardiographic, was present in 9% of the patients and was associated only with a significantly higher mean serum level of the drug.

Microalbuminuria and casual and ambulatory blood pressure monitoring in normotensives and in patients with borderline and mild essential hypertension

Several reports suggest that urinary albumin excretion may be elevated in patients with essential hypertension and that this index may be a good predictor for cardiovascular complications. The aim of this study was to compare 24-hour urinary albumin excretion in a group of normotensives, borderline, and untreated mild hypertertensives and to assess, in a subgroup of them, the possible relations between microalbuminuria and arterial blood pressure. Fifteen normotensives, 16 borderline, and 19 mild hypertensive patients were studied. Slightly but significantly higher values of microalbuminuria were observed in the mild hypertensives compared to the other two groups. In 21 borderline and mild hypertensive patients 24-hour microalbuminuria was related to casual blood pressure and noninvasive ambulatory blood pressure monitoring. A significant correlation was found between microalbuminuria and average day-time diastolic blood pressure. Our data suggest that albumin excretion is slightly increased in mild arterial essential hypertension; the direct association between microalbuminuria and arterial diastolic blood pressure during daily activities seems to confirm a pathophysiological link between transcapillary protein escape and arterial blood pressure that warrants further studies.

Simultaneous liquid-chromatographic determination of urinary vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid

We describe a liquid-chromatographic method for quantifying, simultaneously by a single procedure, vanillylmandelic acid (VMA), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in urine. After solvent extraction of acidified urine, the analytes were chromatographed on a C8 column, with use of a mobile phase of phosphate buffer (20 mmol/L, pH 4.0) and methanol with a variable gradient elution, and detected fluorometrically. We report the analytical recovery, sensitivity, precision, working linear range, and potential for interference from similar molecules or drugs. The results of such tests demonstrate that the proposed method is sensitive and reproducible. It is, furthermore, easy to perform, and thus is suitable for use in the clinical laboratory.

Simultaneous liquid-chromatographic determination of urinary vanillylmandelic acid, homovanillic acid, and 5-hydroxyindoleacetic acid

We describe a liquid-chromatographic method for quantifying, simultaneously by a single procedure, vanillylmandelic acid (VMA), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in urine. After solvent extraction of acidified urine, the analytes were chromatographed on a C8 column, with use of a mobile phase of phosphate buffer (20 mmol/L, pH 4.0) and methanol with a variable gradient elution, and detected fluorometrically. We report the analytical recovery, sensitivity, precision, working linear range, and potential for interference from similar molecules or drugs. The results of such tests demonstrate that the proposed method is sensitive and reproducible. It is, furthermore, easy to perform, and thus is suitable for use in the clinical laboratory.

Increased plasma fibronectin concentration in diabetic patients with microalbuminuria

Raised levels of plasma fibronectin (PF), an alpha 2-glycoprotein produced by vascular endothelia, have been previously described in diabetic patients with retinopathy and overt nephropathy. The aim of this study was to investigate whether the presence of microalbuminuria is associated with increased PF concentrations. Twenty Albustix-negative diabetic outpatients with microalbuminuria [median albumin excretion rate (AER): 30.2 micrograms/min; range 12.1-194 micrograms/min] were compared with 58 sex- and age-matched patients without microalbuminuria (median AER 3.1 micrograms/min; range 0.8-12 micrograms/min) and 34 control subjects (median AER 2.8 micrograms/min; range 0.8-12.1 micrograms/min). Mean PF was significantly higher in the group with microalbuminuria (406.7 +/- 85.5 micrograms/ml) than in the group without it (325.3 +/- 76.5 micrograms/ml or in control subjects (334.5 +/- 76 micrograms/ml; P less than .05). PF increase associated with microalbuminuria was independent of the presence of retinopathy. Furthermore, in the whole group of diabetic patients, PF was significantly correlated with AER (r = .33; P = .003). Such correlation also remained significant (P = .0002) after covariance analysis by a stepwise discriminant procedure taking into account age, duration of disease, sex, blood pressure, body weight, therapy, and HbA1. In conclusion, PF increase is associated with microalbuminuria independent of the other considered variables; its role as a possible marker for early diabetic nephropathy remains to be fully clarified.

Plasma fibronectin in normolipidaemic and hyperlipidaemic uraemic patients treated with haemodialysis

Plasma fibronectin (PF) concentrations, were investigated in normolipidaemic and hyperlipidaemic (type IV) patients with chronic renal failure treated with hemodialysis (n = 29) and in controls (n = 34). Mean PF was significantly reduced in both subsets of dialysed patients. Among the hemodialysed patients the presence of hyperlipidaemia did not modify PF levels, which resulted, on the contrary, significantly higher in hyperlipidaemic controls as compared with the normolipidaemic group. In controls, according to a multivariate analysis model, PF was directly related with age and inversely with HDL-cholesterol. In the hemodialysed patients total cholesterol was the unique significant PF related variate, being this group, therefore, characterized by the lack of any inverse relation between PF and HDL-cholesterol. Finally, no PF modifications were observed in hemodialyzed patients affected by arterial hypertension or clinically evident atherosclerotic lesions.

Plasma fibronectin in diabetic retinopathy and macroangiopathy

To establish the relation between plasma fibronectin (PF) and vascular complications of diabetes mellitus, we studied 163 normotensive diabetic outpatients, of whom 53 were treated with insulin (15 type I, 38 type II) and 110 with sulfonylureas, and compared them to 34 control subjects. Diabetic patients were divided, according to their therapy, into four groups: with retinopathy (classified as background or proliferative) detected by fluorescein angiography (m), with macroangiopathy, assessed by clinical criteria (M), with both vessel complications (mM) and without vascular disease (N). PF was not related to glycosylated hemoglobin (HbA1) in each treatment group (r = 0.26; P = 0.051 in the insulin treated patients and r = 0.09; P = 0.356 in the group on oral drugs). PF levels were similar in M groups, either on insulin or sulfonylureas and in controls. Both m and mM subsets of patients were, conversely, characterized by significantly raised mean PF concentrations when compared to N subjects or controls, but proliferative retinopathy was not associated with a significant PF increase compared to background retinopathy. The differences of PF levels among m, mM and N groups remained significant after processing the data by means of stepwise discriminant analysis with age, duration of diabetes, body weight and HbA1 entering the model as covariates. We conclude that diabetic macroangiopathy is not associated with modifications of mean PF levels, which, on the contrary, appear increased only in diabetic patients with retinopathy, regardless of their therapy.