Assessing individual risk for AMD with genetic counseling, family history, and genetic testing.

PurposeThe goal was to develop a simple model for predicting the individual risk profile for age-related macular degeneration (AMD) on the basis of genetic information, disease family history, and smoking habits.Patients and methodsThe study enrolled 151 AMD patients following specific clinical and environmental inclusion criteria: age >55 years, positive family history for AMD, presence of at least one first-degree relative affected by AMD, and smoking habits. All of the samples were genotyped for rs1061170 (CFH) and rs10490924 (ARMS2) with a TaqMan assay, using a 7500 Fast Real Time PCR device. Statistical analysis was subsequently employed to calculate the real individual risk (OR) based on the genetic data (ORgn), family history (ORf), and smoking habits (ORsm).Results and conclusionThe combination of ORgn, ORf, and ORsm allowed the calculation of the Ort that represented the realistic individual risk for developing AMD. In this report, we present a computational model for the estimation of the individual risk for AMD. Moreover, we show that the average distribution of risk alleles in the general population and the knowledge of parents' genotype can be decisive to assess the real disease risk. In this contest, genetic counseling is crucial to provide the patients with an understanding of their individual risk and the availability for preventive actions.

PCR-based approach for qualitative molecular analysis of six neurotropic pathogens.

In the last few years, polymerase chain reaction analysis is frequently required to improve the detection of pathogen infections in central nervous system as a potential cause of neurological disorders and neuropsychiatric symptoms. The goal of this paper is to set up a fast, cheap and reliable molecular approach for qualitative detection of six neurotropic pathogens. A method based on PCR has been designed and implemented to guarantee the qualitative DNA detection of herpes simplex virus types 1 and 2 (HSVI/II), Epstein-Barr virus (EBV), cytomegalovirus (CMV), varicella-zoster virus (VZV), rubella virus (RUBV) and Toxoplasma gondii in the cerebrospinal fluid, where otherwise they are barely detectable. Each PCR assay was tested using dilutions of positive controls, which demonstrated a sensitivity allowing to detect up to 102 copies/ml in PCR and 10 copies/ml in real-time PCR for each pathogen. Once been set up, the protocol was applied to evaluate the cerebrospinal fluid from 100 patients with suspected infectious diseases of the central nervous system and 50 patients without any infection. The method allowed to identify 17 positive cerebrospinal fluid with polymerase chain reaction and 22 with real-time PCR (RT-PCR), respectively. Therefore, application of RT PCR allows a fast and sensitive evaluation of neurotropic DNA pathogens in the course of diagnostic routine within neurological units.

Methamphetamine increases Prion Protein and induces dopamine-dependent expression of protease resistant PrPsc.

The cellular prion protein (PrPc) is physiologically expressed within selective brain areas of mammals. Alterations in the secondary structure of this protein lead to scrapie-like prion protein (PrPsc), which precipitates in the cell. PrPsc has been detected in infectious, inherited or sporadic neurodegenerative disorders. Prion protein metabolism is dependent on autophagy and ubiquitin proteasome. Despite not being fully elucidated, the physiological role of prion protein relates to chaperones which rescue cells under stressful conditions.Methamphetamine (METH) is a widely abused drug which produces oxidative stress in various brain areas causing mitochondrial alterations and protein misfolding. These effects produce a compensatory increase of chaperones while clogging cell clearing pathways. In the present study, we explored whether METH administration modifies the amount of PrPc. Since high levels of PrPc when the clearing systems are clogged may lead to its misfolding into PrPsc, we further tested whether METH exposure triggers the appearance of PrPsc. We analysed the effects of METH and dopamine administration in PC12 and striatal cells by using SDS-PAGE Coomassie blue, immune- histochemistry and immune-gold electron microscopy. To analyze whether METH administration produces PrPsc aggregates we used antibodies directed against PrP following exposure to proteinase K or sarkosyl which digest folded PrPc but misfolded PrPsc. We fond that METH triggers PrPsc aggregates in DA-containing cells while METH is not effective in primary striatal neurons which do not produce DA. In the latter cells exogenous DA is needed to trigger PrPsc accumulation similarly to what happens in DA containing cells under the effects of METH. The present findings, while fostering novel molecular mechanisms involving prion proteins, indicate that, cell pathology similar to prion disorders can be mimicked via a DA-dependent mechanism by a drug of abuse.

Direct PCR: a new pharmacogenetic approach for the inexpensive testing of HLA-B*57:01.

One of the most successful applications of pharmacogenetics research is the genetic screening for HLA-B*57:01, strongly associated with an increased risk to develop hypersensitivity reaction in HIV-positive patients following abacavir administration. Taking into consideration the limits of current genotyping methodologies, we have developed and validated (150 buccal swabs) an inexpensive pharmacogenetic approach for HLA-B*57:01 typing. In our assay DNA extraction and amplification are combined in one single step (direct PCR protocol), which is performed directly on the biological sample without the need of extraction and sequencing passages. The amplicons obtained by direct PCR can be easily separated on the agarose gel under ultraviolet. As per our results, the direct PCR represents a good alternative to the traditional methods of HLA-B*57:01 pharmacogenetic test, especially for those laboratories or countries where currently available approaches are often not available or not affordable. Furthermore it is an innovative approach, promoting a personalized, safer and cost-effective therapy.

Gene expression profile study in CFTR mutated bronchial cell lines.

Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis conductance transmembrane regulator (CFTR). Symptoms are pancreatic insufficiency, chronic obstructive lung disease, liver disease, chronic sinusitis and infertility in male patients. The phenotypic variability may be explained only in part by the more than 1200 CFTR mutations, which are grouped into six different classes, according to their effect on the protein ranging from a severe (no synthesis or blocked processing) to mild mutation (altered conductance or reduced synthesis). However, it is now accepted that other genes (CF modifiers) influence the phenotypic spectrum of the disease. In order to identify CF modifier genes, we built a low-density home-made oligoarray containing 144 genes selected according to biochemical criteria and evaluated their expression in two CF bronchial epithelial cell lines (CuFi1 F508del/F508del; CuFi3 F508del/R553X). If we consider both cell lines, 38 genes (26.3%) show an altered expression pattern with a threshold > +/-1.5. Of these 38 genes, 12 are altered in CuFi1, and 26 in CuFi3. Some of these genes share the same expression pattern in both cell lines, while others have a different behaviour. These results were validated by a QRT-PCR assay (R2 CuFi1 = 0.81 and R2 CuFi3 = 0.91). These data could suggest that the presence of a class I allele (R553X) determines a more profound alteration of gene expression pattern than the presence of a class II allele (F508del). The identification of the genes altered by a specific CF mutation could lead to the development of a pharmacological approach specific for different CFTR genotypes.

Factors determining the 24-h blood pressure profile in normotensive patients with type 1 and type 2 diabetes.

Some controversy still exists about factors involved in the abnormal circadian pattern of blood pressure (BP) in diabetes, while prognostic value of non-dipping condition is being increasingly recognised. This study was aimed at evaluating the relative influence of autonomic neuropathy (AN) and albumin excretion on 24-h BP profile in type 1 and type 2 diabetes. We measured AN cardiovascular tests, 24-h ambulatory BP, and urinary albumin excretion rate (UAE) in 47 type 1 and 34 type 2 normotensive non-proteinuric diabetic patients. In type 1 diabetic patients day-night differences (Delta) in systolic and diastolic BP were lower in those with AN than in those without (3 +/- 9 vs 10 +/- 6%, P < 0.01, and 8 +/- 9 vs 16 +/- 6%, P < 0.001), and in univariate regression analysis they were inversely related to both autonomic score, index of degree of AN (r = -0.61, P < 0.001 and r = -0.65, P < 0.001), and to 24-h UAE (r = -0.39, P < 0.01 and r = -0.46, P < 0.001). In type 1 diabetic patients AN was also associated with lower nocturnal decrease in UAE (patients with AN vs without AN: -37 +/- 214 vs 49 +/- 37%, P < 0.05), and with a stronger relationship between simultaneous 24-h UAE and 24-h BP (for systolic BP patients with AN vs without AN: r = 0.62, P < 0.01 vs r = 0.28, NS). In type 2 diabetic patients Delta systolic BP was reduced in patients with AN compared to those without (4 +/- 7 vs 10 +/- 4%, P < 0.01), and it was related only to autonomic score (r = -0.42, P < 0.01). Using a stepwise regression analysis, in type 1 diabetic patients autonomic score was the variable of primary importance for Delta BP, while in type 2 diabetic patients it was the unique determinant not only of Delta systolic BP but also of 24-h systolic BP. In conclusion, AN is the pivotal factor of blunted nocturnal fall in BP in both type 1 and type 2 diabetic patients. In type 1 diabetic patients AN is associated with attenuated circadian pattern of albuminuria and with a steeper relationship between albuminuria and BP, in type 2 diabetic patients AN is the only factor related to elevated 24-h BP levels. Longitudinal studies are needed to establish the potential role of autonomic dysfunction as a progression promoter for nephropathy and hypertension in type 1 and type 2 diabetes respectively.

Hyperinsulinaemia in offspring of Type 2 diabetic patients: impaired response of carbohydrate metabolism, but preserved cardiovascular response.

AIMS: To investigate the effects of endogenous insulin on haemodynamics in nine offspring of Type 2 diabetic patients (P), compared with 18 subjects without family history of diabetes (C), all with normal glucose tolerance. METHODS: All subjects underwent a 180-min oral glucose tolerance test with continuous blood pressure and ECG recording. Low-to-high frequency ratio (LF/HF), an index of the sympatho-vagal balance, was calculated by heart rate spectral analysis. RESULTS: At baseline, LF/HF correlated with fasting plasma insulin (r = 0.44, P < 0.03) and with insulin/glucose ratio (r = 0.46, P < 0.03). Plasma insulin, basally similar in the two groups, was significantly increased in P (342 +/- 34.2) when compared to C (177.6 +/- 25.2 pmol/l), P < 0.005 from time 30min onward. Blood glucose, also similar at baseline, remained not significantly different in P (5.74 +/- 0.25) vs. C (5.08 +/- 0.27 mmol/l), throughout the study. Diastolic blood pressure significantly decreased in P, but not in C during the first hour of the study. Finally, LF/HF ratio significantly increased in P (2.5 +/- 0.4 vs. C, 1.7 +/- 0.2) during the first hour. CONCLUSIONS: In conclusion, the offspring of Type 2 diabetic patients with normal glucose tolerance display an increased insulin secretion; however, they are not resistant to the haemodynamic effects of insulin, as suggested by the reduction of diastolic blood pressure. This, in turn, may determine a chronic sympathetic activation, which could be involved in the pathogenesis of Type 2 diabetes mellitus.

[The echo-stress test with dipyridamole-atropine on the 3rd-5th day of an uncomplicated acute myocardial infarct for risk stratification and early discharge]. / Eco-stress con dipiridamolo-atropina in terza-quinta giornata nell'infarto miocardico acuto non complicato per la stratificazione del rischio e la dimissione precoce.

BACKGROUND: The aim of this study was to evaluate if dipyridamole-atropine stress echocardiography (DASE) performed between the third-fifth day in uncomplicated acute myocardial infarction allows for an effective risk stratification with an early discharge in some cases. METHODS: Between February 1997 and September 1998, 190 patients (138 males and 52 females, mean age 59 +/- 10.3 years), with acute myocardial infarction, were enrolled in the study. DASE was performed between the third-fifth day with a dipyridamole infusion of 0.84 mg/kg over 10 min followed by 1 mg of atropine from the twelfth to the fifteenth minute. DASE was considered positive in the presence of a new or worsening dyssynergy. Patients with heart failure, angina, major arrhythmias, and poor acoustic window were excluded. In the follow-up spontaneous events were defined as cardiac death, non-fatal myocardial reinfarction, unstable angina or heart failure (with hospitalization). RESULTS: DASE was performed in 92 patients (48.4%), all without complications: 29 patients (31.5%) had a negative DASE result, and 63 patients (68.5%) had a positive DASE. The average hospital stay of patients with a negative test was significantly lower in comparison with that of patients with a positive test (7.55 +/- 1.32 vs 9.29 +/- 1.61 days, p < 0.0001). Events occurred in 19 patients (20.6%), 2/29 patients with a negative DASE (6.9%), 17/63 patients with a positive DASE (27%), 6/43 patients with homozonal positivity after atropine or high-dose dipyridamole (14%), 11/20 patients with heterozonal positivity or homozonal positivity after low-dose dipyridamole (55%). On univariate analysis the variables significantly associated with spontaneous events were: age (chi 2 = 6.41, p = 0.019), left ventricular ejection fraction at rest (chi 2 = 8.89, p = 0.004), number of asynergic segments after stress (chi 2 = 6.87, p = 0.010), increase in the number of asynergic segments after stress (chi 2 = 4.01, p = 0.039), wall motion score index after stress (chi 2 = 9.60, p = 0.003), increase in wall motion score index after stress (chi 2 = 3.60, p = 0.049), DASE positivity (chi 2 = 4.89, p = 0.029), homozonal positivity after low-dose dipyridamole (chi 2 = 8.57, p = 0.013), heterozonal positivity (chi 2 = 13.10, p = 0.001). On Cox's multivariate analysis independent predictors of events were: age (relative risk 3.92, p = 0.0146), DASE positivity (relative risk 1.79, p = 0.0054). CONCLUSIONS: DASE between the third-fifth day in uncomplicated acute myocardial infarction is feasible, tolerable, safe, and effective for early risk stratification. A negative DASE detects a "very low-risk" patient group, and allows for an earlier hospital discharge, without an increased risk of events. The heterozonal positivity or the homozonal positivity after low-dose dipyridamole indicates the need for a coronarography, due to the high risk of events at follow-up.

Assessment of sympathetic innervation of the heart in diabetes mellitus using 123I-MIBG.

Radio-labeled metaiodobenzylguanidine (MIBG) is considered an established sympathetic neuron imaging agent capable of scintigraphically visualizing the organs richly innervated by the sympathetic nervous system. Its clinical applications now include cardiac and pulmonary adrenergic imaging. The quantitative determination of global and/or regional abnormalities of MIBG heart uptake has been demonstrated to be very useful in several clinical settings representing one of the major determinants of adverse prognosis. The presence and the severity of autonomic neuropathy are known as important prognostic factors in patients with diabetes. MIBG scintigraphy is able to non-invasively assess and characterize the adrenergic abnormalities of the cardiac innervation also in these patients. In order to evaluate whether 123I-MIBG is able to reveal abnormalities of myocardial adrenergic function in different groups of diabetic patients, we performed 123I-MIBG scintigraphy in control subjects and in normotensive Type 1 diabetic patients with and without autonomic neuropathy (N+ and N- patients), selected according to results of cardiovascular reflex tests. Regional abnormalities of adrenergic innervation were revealed in 10% of control subjects, in 70% of N- patients and in 100% of N+ patients. The finding of a higher than expected prevalence of MIBG regional abnormalities in patients without signs or symptoms of autonomic neuropathy allows to hypothesize that cardiac autonomic nervous damage occurs earlier than previously known in diabetic patients whose cardiovascular tests are still completely normal.

[Dipyridamole-echocardiography and thallium exercise myocardial scintigraphy in the diagnosis of obstructive coronary or microvascular disease in hypertensive patients with left ventricular hypertrophy and angina]. / Eco-dipiridamolo e miocardioscintigrafia da sforzo al tallio nella diagnosi di coronaropatia ostruttiva o malattia microvascolare in pazienti ipertesi con ipertrofia ventricolare sinistra e angina.

BACKGROUND: Hypertensive patients with left ventricular hypertrophy can be affected with angina pectoris for significant epicardial coronary stenosis or microvascular disease with normal coronarography. Exercise-electrocardiography test is positive in both conditions. The aim of the present study was to assess the accuracy of dipyridamole-echocardiography test and thallium exercise myocardial scintigraphy in the diagnosis of epicardial coronary stenosis or microvascular disease in hypertensive patients with left ventricular hypertrophy and angina pectoris. METHODS: Forty-two hypertensive patients (22 males, age 40-76 years, mean 58.6 +/- 10.1), with left ventricular hypertrophy, typical angina pectoris, ischemia that can be induced by exercise-electrocardiography test, without previous myocardial infarction, myocardial revascularization or diabetes mellitus, underwent dipyridamole-echocardiography test, thallium exercise myocardial scintigraphy and coronarography. Dipyridamole-echocardiography test was performed with dipyridamole (0.56 mg/kg over 4 minutes, followed by 0.28 mg/kg from the 8th to the 10th minute) + atropine (1 mg from the 12th to 15th min.) and was positive for a transient dyssynergy of contraction of at least 2 myocardial segments; the left ventricle was divided into 16 segments. SPECT thallium myocardial scintigraphy was performed after bicycle exercise and then three hours later, and it was positive for reversible uptake defects of at least 2 segments with a 22-segment model. Coronarography was performed with Judkin's technique and was positive if at least one large epicardial vessel was narrowed by more than 50%. RESULTS: Coronarography: normal in 25 cases (59.5%, 8 males), pathologic in 17 (40.5%, 14 males): left main coronary artery in 1 (5.9%), three vessels in 5 (29.4%), two vessels in 3 (17.7%), 1 vessel in 8 (47%). Dipyridamole-echocardiography-test: positive in 15 cases (35.7%), negative in 27 (64.3%); sensitivity 88.2%, specificity 100%, diagnostic accuracy 95.2%, positive predictive value 100%, negative predictive value 92.6%. Thallium exercise myocardial scintigraphy: positive in 30 cases (71.4%), negative in 12 (28.6%); sensitivity 100%, specificity 48%, diagnostic accuracy 69%, positive predictive value 56.7%, negative predictive value 100%. CONCLUSIONS: Dipyridamole-echocardiography test has higher diagnostic accuracy and when positive, it predicts significant epicardial coronary stenosis. It can be less sensitive in one-vessel patients (2 false negatives were stenosis 75% of left anterior descending and 60% of 1st diagonal). Thallium exercise myocardial scintigraphy is complementary because when negative, it excludes epicardial coronary stenosis and confirms microvascular disease. In hypertensive patients with left ventricular hypertrophy and suspected angina pectoris, the following flow-chart may be proposed: the first test is exercise-electrocardiography test. Only those who are positive at low-to-intermediate workload then undergo dipyridamole-echocardiography test. Those who are positive in this then undergo coronarography, while the negative ones undergo thallium exercise myocardial scintigraphy. Those who are positive at thallium exercise myocardial scintigraphy perform the coronarography, while cases with negative results do not undergo further diagnostic tests since they are affected with microvascular disease.

Radiographic evaluation of the soap man mummy.

This article describes how mobile radiography was used to examine a mummified cadaver exhumed in 1875 and stored in the Smithsonian Museum. Radiographs revealed artifacts imbedded in the cadaver, indicating 1824 as the earliest possible interment. Through radiographic assessment of the skeleton, researchers were able to approximate the individual's age at death. In addition, evidence of pathology, possibly ideopathic skeletal hyperostosis, suggested the individual may have been employed in manual labor. The radiographs, when compared to x-rays of another cadaver exhumed at the same time and place, refuted information in museum records.

Effects of beta-adrenergic blockade on insulin-mediated glucose disposal in hypertensive and normotensive rats.

OBJECTIVE: To evaluate the impact of beta-adrenergic blockade in spontaneously hypertensive rats (SHR) and in their normotensive controls, Wistar-Kyoto (WKY) rats, on whole-body glucose disposal under metabolic steady state conditions, in unrestrained and conscious animals. METHOD: SHR (n = 13) and WKY rats (n = 12) underwent a 240 min insulinaemic clamp study with or without a super-infusion (120th to 240th minutes; second step) of propranolol. RESULTS: From 0 to 120 min (the first step) SHR showed significantly increased glucose uptake, muscle glycogen synthesis and glycogen synthase activity compared with WKY rats. When propranolol was superinfused, glucose uptake and muscle glycogen synthesis in SHR returned to levels similar to those observed in WKY rats during the first step. No significant differences were found for whole-body glycolysis in SHR and WKY in the first and second steps. CONCLUSION: Hypertensive rats display an increased insulin sensitivity compared with controls. Beta-Blockade is associated with a reduction in overall glucose metabolism in SHR, but not in WKY rats.

[Ecology of sandflies in Serra do Mar, Itaguaí, state of Rio de Janeiro, Brazil. I - Sandfly fauna and prevalence of the species in collections sites and method of capture] / Ecologia dos flebotomíneos da Serra do Mar, Itaguaí, Estado do Rio de Janeiro, Brasil. I - A fauna flebotomínica e prevalência pelo local e tipo de captura (Diptera, Psychodidae, Phlebotominae).

A two-year investigation was conducted in Itaguai, State of Rio de Janeiro, an area with cases of cutaneous leishmaniasis, in order to study the ecology of sandflies and their habits and role as parasitic vector for men and animals. Capturing took place at three sites: domiciliary (human bait, walls, and light traps); peridomiciliary (walls, from baits used simultaneously: humans, dogs, and chickens; and light traps); and sylvatic (human bait and light traps). A total of 10,172 sandflies were captured, belonging to 17 species of genuses Brumptomyia França & Parrot, 1921 and Lutzomyia França, 1924. L. intermedia was predominant, 100 m above sea level, as compared to L. migonei and L. fischeri. In a drier area 300 m above sea level L. migonei was prevalent, followed by L. longipalpis and L. fischeri. The species which presented the greatest endophily was L. fischeri, showing a certain degree of eclecticism regarding the biting site. L. intermedia and L. migonei proved to be more exophilic. L. intermedia was considered to be potentially the main transmitter of the disease because of its prevalence, anthropophily, and the fact it is known to be a vector of Leishmania (V.) braziliensis in other areas of the Southeastern region of Brazil. L. fischeri, because of its anthropophily, might also be involved.

Effects of insulin on cholesterol synthesis in type II diabetes patients.

OBJECTIVE: To evaluate the effects of intensive insulin therapy and subsequent optimized metabolic control on daily urinary mevalonic acid (MVA) excretion, an index of whole-body cholesterol synthesis, and the acute effects of insulin on plasma MVA concentrations in type II diabetes. RESEARCH DESIGN AND METHODS: Ten (five men and five postmenopausal women) nonobese, normolipidemic (total cholesterol < 6.2 mmol/l, triglycerides < 2.82 mmol/l), type II diabetic patients in poor metabolic control (HbA1c > 10%, fasting plasma glucose > 11 mmol/l) and receiving sulfonylurea treatment were selected. The 24-h urinary MVA excretion and plasma lipid values were determined before and after intensive insulin therapy. The acute effects of insulin on plasma MVA concentrations were also evaluated during a 3-h euglycemic hyperinsulinemic clamp study. RESULTS: Urinary MVA excretion rates (mumol/24h) were 1.82 +/- 0.21 in control subjects and 2.49 +/- 0.35 (P < 0.01 vs. control subjects) and 1.78 +/- 0.28 in patients before and after intensive insulin therapy, respectively. Total cholesterol, low-density-lipoprotein (LDL) cholesterol, and triglycerides decreased by 9, 8, and 12%, respectively, after blood glucose optimization. Acute insulin infusion during the euglycemic clamp studies reduced mean plasma MVA concentrations at 120 and 180 min by 29 and 38%, respectively (P < 0.01 for both vs. baseline). CONCLUSIONS: Our study demonstrates that in nonobese, normolipidemic, type II diabetic patients under poor metabolic control, an increased cholesterol synthesis is normalized by insulin therapy. Hyperinsulinemia in the presence of euglycemia acutely decreases the circulating levels of MVA, the immediate product of hydroxymethylglutaryl-CoA reductase activity and an index of whole-body cholesterol synthesis.

Glycogen synthase activity in two rat models of hypertension.

Several studies on both humans and animal models have reported a pathogenetic relationship among hyperinsulinism, insulin resistance, and hypertension. We have previously evaluated whole body glucose disposal and insulin sensitivity in different models of hypertensive rats, showing an increase rather than an impairment of glucose metabolism, which in turn was due to an improved ability of insulin to channel the absorbed glucose towards the nonoxidative disposal. Aiming to confirm our previous findings we performed the direct assay of skeletal muscle glycogen synthase on tissue samples from the previous clamp studies, as a rate limiting step enzyme of glycogen synthesis, under conditions of physiologic hyperinsulinemia and euglycemia. Glycogen synthase was assayed on samples from rectus muscle tissues of spontaneously hypertensive rats and high sodium, one kidney, one figure-8 hypertensive rats. Compared to controls, our data show an increased activity of glycogen synthase in the hypertensive animals, which is consistent with the increased glycogen synthesis previously reported. In conclusion, under our experimental conditions, hypertension and chronic hyperadrenergism are associated with an increased ability of insulin to stimulate glucose uptake and disposal. These latter effects are mainly due to an increase in nonoxidative disposal and glycogen synthase activity.

Relationship between autonomic neuropathy, 24-h blood pressure profile, and nephropathy in normotensive IDDM patients.

OBJECTIVE: To evaluate the relationship between autonomic neuropathy, nephropathy, and 24-h blood pressure (BP) pattern in insulin-dependent diabetes mellitus (IDDM). RESEARCH DESIGN AND METHODS: We studied 30 normotensive IDDM patients without overt nephropathy, divided into two groups and matched for age, duration of diabetes, and HbA1, according to the presence of cardiovascular autonomic neuropathy. We simultaneously measured 24-h BP and urinary albumin excretion rate (UAE) on urine collections timed overnight and at 2-h intervals during the day. RESULTS: Mean day and night systolic and diastolic BP values did not significantly differ between the groups. Mean night albuminuria was significantly higher in patients with autonomic neuropathy than in those without (61.4 +/- 104.6 [mean +/- SD] vs. 16 +/- 25.2 micrograms/min, P < 0.04). The percentages day-night changes in systolic BP, diastolic BP, and UAE were significantly lower in neuropathic patients (systolic BP: 2.4 +/- 7.7 vs. 9.6 +/- 4.2%, P < 0.001; diastolic BP: 8.4 +/- 6.9 vs. 15.5 +/- 5.4%, P < 0.002; UAE: -8 +/- 99.4 vs. 49.3 +/- 29.4%, P < 0.02) and were inversely related to autonomic score, index of autonomic neuropathy degree (r = -0.54, P < 0.002; r = -0.58, P < 0.001; and r = -0.53, P < 0.005, respectively). In patients with autonomic neuropathy, 2-h day periods and day and night UAE were more strongly related, respectively, to mean 2-h day periods (r = 0.58, P < 0.0001), day systolic BP (r = 0.67, P < 0.04), and night systolic BP (r = 0.69, P < 0.04) than in patients without autonomic neuropathy (2-h day periods: r = 0.32, P < 0.001; day: r = 0.37, NS; night: r = 0.35, NS). CONCLUSIONS: Autonomic neuropathy in IDDM patients is associated with reduced nocturnal falls in BP and UAE and with a stronger relationship of UAE to systolic BP. We suggest a pathogenetic role of autonomic neuropathy in the development of diabetic nephropathy through changes in nocturnal glomerular function and by enhanced kidney vulnerability to hemodynamic effects of BP.

The effects of insulin on plasma mevalonate concentrations in man.

Mevalonate production is a limiting step in cholesterol synthesis. We studied the effects of insulin on plasma mevalonate concentrations during a 3-hour euglycemic hyperinsulinemic clamp study in 10 healthy males starting at 9 h a.m. after 14 h of fasting. Physiological variations in plasma mevalonate were evaluated on a different day from 9 to 12 h a.m. under saline infusion. During the clamp studies, slight but significant decreases were noted for VLDL-triglyceride and VLDL-cholesterol at 120 and 180 min (p < 0.05) and for apolipoprotein B-100 from 60 min on (p < 0.05). Plasma mevalonate decreased significantly by 34 and 41% at 120 and 180 min, respectively (p < 0.001), while the mean percent decrease due to diurnal variations was 12% at 12 h a.m. In conclusion, hyperinsulinemia in the presence of euglycemia acutely decreases the circulating levels of mevalonic acid, the immediate product of HMG CoA reductase in the cholesterol pathway.

Relationship between the circadian rhythms of blood pressure and sympathovagal balance in diabetic autonomic neuropathy.

In diabetic autonomic neuropathy, abnormal circadian patterns of blood pressure and sympathovagal balance with reduced fall of blood pressure and prevalence of sympathetic activity during the night have been described. To correlate the abnormalities of blood pressure to those of sympathovagal balance, we simultaneously performed 24-h noninvasive monitoring of blood pressure and ECG in 25 diabetic patients (45.6 +/- 13.6 yr of age with a 17.6 +/- 9.1 yr duration of diabetes) with various degrees of cardiovascular reflex impairment. Autoregressive power spectrum analysis of RR interval variability was applied to 24-h ECG recordings to obtain for day and night periods the mean power of low- (0.03-0.15 Hz) and high-frequency (0.18-0.40 Hz) components, which are relative markers of sympathetic and vagal activity, respectively, and their ratio (low frequency/high frequency), assumed as index of sympathovagal balance. Diabetic patients showed a lower percentage of day-night change in systolic blood pressure (9 +/- 5.48 vs. 11.6 +/- 4.78%, P < 0.037), a lower day low frequency (5.9 +/- 0.81 vs. 6.62 +/- 0.73 In-ms2, P < 0.001), a lower night high frequency (6.06 +/- 0.71 vs. 6.52 +/- 0.85 In-ms2, P < 0.05), a lower day low frequency:high frequency ratio (1.82 +/- 1.77 vs. 3.05 +/- 1.82, P < 0.01), and a lower percentage of day-night change in low-frequency:high frequency ratio (-13.4 +/- 109.9 vs. 28.7 +/- 29.7%, P < 0.05), when compared with control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased left ventricular mass in normotensive diabetic patients with autonomic neuropathy.

The possible relationship between diabetic autonomic neuropathy, circadian blood pressure changes, and echocardiographic parameters was investigated in 27 normotensive diabetic patients (10 with and 17 without autonomic neuropathy) who underwent 24 h noninvasive ambulatory blood pressure monitoring and M-mode echocardiographic recording. The two groups were comparable for age, sex, duration of diabetes, body mass index, and metabolic control. There were no significant differences in 24 h average and diurnal values of systolic, diastolic, or mean blood pressure. The percent changes from day to night of systolic, diastolic, and mean blood pressures were significantly lower in diabetics with neuropathy than in those without (P < .04 or less). Increased left ventricular mass index (LVMI) (135.4 +/- 10.2 v 102.9 +/- 6.3; P < .005), septal wall thickness, and posterior wall width were observed in neuropathic patients. Fractional shortening, peak velocity of early left ventricular filling (E), peak velocity of late ventricular filling (A), and their ratio (E/A) were similar in the two groups. The increased LVMI we observed may represent a possible link between diabetic autonomic neuropathy, nocturnal blood pressure levels, and higher cardiovascular mortality rate.