Comparison between different laboratory tests for the detection and prevention of heparin-induced thrombocytopenia

BACKGROUND

Heparin-induced thrombocytopenia (HIT) is a possible complication of heparin therapy that can evolve with life-threatening thromboembolism, for which early diagnosis is essential. However, the specific laboratory approach to the diagnosis of HIT is still controversial.

METHODS

Sera from 13 patients with HIT, from 15 patients with non-HIT thrombocytopenia, and from 10 normal subjects were used to compare nonfunctional and functional methods to detect anti-heparin:PF-4 antibodies and platelet activation. We used three enzyme-linked immunosorbent assays (ELISAs) and the particle gel immunoassay as nonfunctional tests, and platelet aggregometry, CD62p (p-selectin) phenotypical expression, and Annexin V binding as functional assays.

RESULTS

CD62p expression was positive in 85% of the cases and Annexin V was positive in 40% of the HIT cases examined. Aggregometry gave variable results that depend strongly on the donor.

CONCLUSION

Functional tests for platelet activation are more reliable for HIT diagnosis than the nonfunctional tests. We conclude that the phenotypical expression of p-selectin detected by flow cytometry on activated platelets appears to be a good functional marker for the diagnosis of HIT and its possible thromboembolic complications.

Prevalence of undiagnosed coeliac syndrome in osteoporotic women

OBJECTIVES

The aims of the study were to quantify the prevalence of asymptomatic coeliac disease (CD) in a cohort of osteoporotic females, and to investigate the features of bone loss.

DESIGN AND SUBJECTS

We studied 255 women (mean age 66.6 +/- 8.5 SD) with primary osteoporosis (WHO diagnostic criteria). After the first CD screening with the measure of serum IgG antigliadin antibodies (IgG-AGA), 53 women showed a positive test: antibodies to tissue transglutaminase (TG-ab) were subsequently determined to confirm the diagnosis of CD. Bone metabolism was evaluated by: serum and urinary calcium, serum and urinary phosphate, serum alkaline phosphatase, urinary crosslaps, serum 25(OH)D and serum parathyroid hormone.

RESULTS

High levels of IgG-AGA and TG-ab were observed in 24 patients with a prevalence of serological disease of 9.4%. These women were characterized, in comparison with the other patients, by a statistically significant reduction in serum 25(OH)D (17.8 +/- 7.2 vs. 55.1 +/- 20.3 nmol L(-1), P < 0.01) together with a significant increase of iPTH (65.1 +/- 29.7 vs. 35.1 +/- 20.0 pg mL(-1); P < 0.01). Patients with high TG-ab levels showed also slightly raised values of urinary crosslaps (288 +/- 88 vs. 270 +/- 90 microm mol(-1) Cr). In IgG-AG positive patients a statistically significant inverse correlation was found between 25(OH)D serum levels and log-transformed TG-ab values (r: -0.95, P < 0.001). Intestinal biopsies were obtained in 10 TG-ab positive women and verified CD in six patients.

CONCLUSIONS

These data support the hypothesis that patients with undiagnosed celiac disease develop high remodelling processes related to calcium malabsorption, secondary hyperparathyroidism and unavailability of vitamin D with a consequent more marked bone loss.

Leptin and body composition in healthy postmenopausal women

BACKGROUND

Leptin has been proposed to be involved in central control of adiposity and fat distribution but the role of this peptide is controversial. The aim of our study was to test the relationship between serum leptin and body composition, fat distribution, and some biochemical markers such as fasting insulinemia and lipoproteins in a population of healthy Italian postmenopausal women.

METHODS

One hundred and twenty-three postmenopausal women (62.1+/-8.7 years) were evaluated. Body composition (fat and lean mass) was assessed by dual-energy X-ray absorptiometry (DXA). Two regions of interest were determined for regional fat analysis. Serum leptin and insulinemia were measured by radioimmunoassay, lipoproteins with colorimetric methods and apolipoproteins nephelometrically.

RESULTS

Plasma leptin levels are strongly related to total fat mass, in grams (r=0.73, p<0.001) or as a percentage of soft tissue (r=0.75, p<0.001), and to adiposity, calculated as ratio between lean and fat mass (r=0.76, p<0.001). A significant correlation was also found between serum leptin and central fat distribution (r=0.29, p<0.01). As concerns biochemical markers, serum leptin was significantly related to fasting insulin (r=0.38, p<0.001), total cholesterol (r=0.29, p<0.01), Apolipoprotein-B (r=0.35, p<0.001), and triglycerides (r=0.22, p<0.05). When corrected for total fat mass, the partial correlation coefficients remain significant for percentage of total body fat (r=0.27, p<0.01), adiposity (r=0.23, p<0.01), and fat proportion in android region (r=0.18, p<0.05).

CONCLUSIONS

These data indicate that leptin levels are related to adiposity and fasting insulin levels; indeed fast insulin mantains significant correlation with leptin (r=0.23, p<0.01) after controlling for fat mass. Android distribution of fat mass in elderly women is associated with leptin concentration.

Iloprost suppresses connective tissue growth factor production in fibroblasts and in the skin of scleroderma patients

Patients with scleroderma receiving Iloprost as a treatment for severe Raynaud's phenomenon report a reduction in skin tightness, suggesting that this drug inhibits skin fibrosis. Connective tissue growth factor (CTGF), a recently described profibrotic cytokine, acts downstream and in concert with TGF-beta to stimulate the fibrotic process and is involved in the fibrosis seen in scleroderma. Here we show that Iloprost, acting by elevation of cAMP, blocks the induction of CTGF and the increase in collagen synthesis in fibroblasts exposed to TGF-beta. The potency of Iloprost with respect to suppression of CTGF far exceeds that of other prostanoid receptor agonists, suggesting that its effect is mediated by the prostacyclin receptor IP. By sampling dermal interstitial fluid using a suction blister device, we show that CTGF levels are greatly elevated in the dermis of scleroderma patients compared with healthy controls and that Iloprost infusion causes a marked decrease in dermal CTGF levels. These studies suggest that Iloprost could be reducing the level of a key profibrotic cytokine in scleroderma patients and that endogenous production of eicosanoids may limit the fibrotic response to TGF-beta.

Isolated temporomandibular synovitis as unique presentation of juvenile idiopathic arthritis

Temporomandibular joint (TMJ) involvement is quite frequent in juvenile idiopathic arthritis (JIA). We describe a 15-year-old girl with isolated TMJ arthritis presenting as a unique manifestation of JIA, and its successful treatment. She underwent arthroscopic synovectomy followed by intraarticular steroid injection. Early use of synovectomy and intraarticular steroids in TMJ arthritis may reduce pain, improve jaw function, and prevent irreversible deformities.

[Molecular characterization of glucose-6-phosphate dehydrogenase deficiency in the Han and Li nationalities in Hainan, China and identification of a new mutation in human G6PD gene]

OBJECTIVE

To elucidate the molecular basis of G6PD deficiency in the Han and Li nationalities in Hainan, China.

METHODS

Polymerase chain reaction and restriction enzyme digestion were used to screen the mutations 1388G-->A, 1360C-->T, 1024C-->T, 592C-->T, 517T-->C, 493A-->G, 487G-->A, 392G-->T and 95A-->G. Single strand conformation polymorphism analysis was used to screen the other mutations followed by DNA sequencing to characterize the mutations of the samples with abnormal SSCP bands.

RESULTS

Of the fifty-nine Han cases with G6PD deficiency, fourteen with 1388G-->A (23.7%), three with 871G-->A(5.1%), one with 835A-->T(1.7%), one with 517T-->C (1.7%), three with 392G-->T(5.1%), and four with 95A-->G(6.8%) were found. Of the thirty-two Li cases with G6PD deficiency, six with 1388G-->A(18.8%), three with 871G-->A(9.4%), and two with 95A-->G(6.3%) were found. A new mutation 835A-->G which causes the substitution of Ala for Thr at 279 in a Han case was identified and named as G6PD Haikou. The enzyme activity of the variant is about 10% of the normal and lower than the activity of the variant 835A-->T with about 40% of the normal. Analysis of the 3D model of human G6PD has revealed that the hydroxyl group of Thr at 279 is a group in maintaining the interaction of the G6PD subunits.

CONCLUSION

The most common mutations of G6PD deficiency in Han and Li nationalities in Hainan are similar. Compared with the mutation spectrum of G6PD gene in the populations in other regions of China, the results indicate that some G6PD gene mutations are widespread in the populations of different regions in the southern part of China. The hydroxyl group of the Thr at 279 of human G6PD may be a necessary group for maintaining the interaction of the G6PD subunits and the enzyme activity.

Heart rate variability in childhood obesity

Obesity is characterized by hemodynamic and metabolic alterations. Autonomic control on cardiac function involvement is controversial. The aim of the study was to assess early sign of cardiac autonomic dysfunction in obesity, using time- and frequency-domain heart rate variability (HRV) analysis in a pediatric population.

METHODS

32 obese children (OB) (17 M, 15 F; 13.9 +/- 1.7 y) were compared with 13 healthy lean subjects (7 M, 6 F; 12.9 +/- 1.6 y). For each participant, the authors performed a clinical examination, laboratory testing, blood pressure (BP) measurements, and 24-hour electrocardiograph/ambulatory BP monitoring. The spectral power was quantified in total power, low-frequency (LF) power, index of sympathetic tone, high-frequency (HF) power, index of vagal tone, and LF/HF ratio. Low frequency and HF were averaged to obtain 3 measures: 24-hour, daytime, and nighttime levels. Total, long-term, and short-term time-domain HRV values were calculated.

RESULTS

The obese children had higher casual and ambulatory BP, and higher fasting glucose, insulin, and triglyceride levels. Overall HRV values were not significantly lower in OB. The obese children had significantly lower 24-hour and nighttime high-frequency normalized units, and time-domain measures of vagal activity. Low-frequency power showed an inverse but not significant pattern. The OB group had significantly greater 24-hour and nighttime LF/HF ratios.

CONCLUSIONS

The authors found an increase in heart rate and in BP associated with parasympathetic heart rate control decrease in stabilized obese normotensive children.

Ambulatory blood pressure monitoring and clinical characteristics of the true and white-coat resistant hypertension

The resistant hypertension has been differentiated in true resistant hypertension and white-coat resistant hypertension by using ambulatory blood pressure monitoring. White-coat resistant hypertension was defined as high clinic blood pressure, despite triple treatment for at least 3 months, but day-time blood pressure values < 135/85 mmHg. The aim of this study was to evaluate the presence of different clinical characteristics between two types of resistant hypertension. The study group consisted of 49 patients with essential hypertension, resistant to an adequate and appropriate triple-drug therapy, that included a diuretic, with all 3 drugs prescribed in near maximal doses and that had persistently elevated clinic blood pressure (> 140/90 mm Hg), for at least 3 months. They represented the 2% of 2500 hypertensive outpatients that referred at our Hypertension Unit. Patients with white-coat resistant hypertension (n=19) were older (p<0.05) than those with true resistant hypertension (n=30). The sodium intake (p<0.05) and alcohol intake (p<0.05) were significantly higher in patients with true resistant hypertension than in those with white-coat resistant hypertension. The renin plasma activity and plasma aldosterone were higher (p<0.05) in patients with true resistant hypertension than in those with white-coat resistant hypertension with normal plasma electrolyte balance. There were no significant differences in mean values of office systolic and diastolic blood pressures between white coat resistant hypertensives and true resistant hypertensives (165+17 vs 172+28 and 98+12 vs 102+14 mmHg). Day-time and night-time ambulatory 24-h-systolic and diastolic blood pressures were significantly higher in the true resistant hypertensive patients when compared with white-coat resistant hypertensives (153+15 vs 124+10 mmHg and 97+9 vs 76+6 mmHg all p<0.001). Day-time and night-time ambulatory 24-h-heart rate were significantly higher in the true resistant hypertensive patients when compared with white-coat resistant hypertensives (79+11 vs 71+9 beats/min; p<0.01; 68+9 vs 60+6 beats/min, p<0.001). The ABP readings were analysed by a Fourier series with 4 harmonics. According to the runs test both two groups of patients showed a circadian rhythm for both systolic and diastolic blood pressure. The nocturnal fall in SBP, DBP and HR was not different in both groups of patients. In conclusion, our findings showed that true resistant hypertensive patients were characterized both by higher heart rate and higher plasma renin activity values as an expression of a possible increased sympathetic activity. Thus, the combination of ABPM with the assessment of the clinical characteristics allow to differentiate better the true drug-resistant hypertension from the white coat resistant hypertension.

Heart rate variability and left ventricular diastolic function in patients with borderline hypertension with and without left ventricular hypertrophy

The relationships between heart rate variability (HRV), left ventricular mass and diastolic function in borderline hypertensive patients (BHT) were evaluated. 24 h Holter electrocardiogram (ECG) and blood pressure (BP) monitoring, M and 2 D echocardiogram and Doppler analysis in 42 BHT with and without left ventricular hypertrophy (LVH) and in 20 normotensive controls were assessed. From 24-h ECG, time domain indexes of HRV were calculated. Standard Deviation of all Cycles (SDNN) and Standard Deviation of the means of heart periods over five-minute intervals (SDANN) were significantly reduced in BHT with LVH but not in BHT without LVH. No significant differences of short-term variability measures were detectable, although a progressive decrease among control subjects and BHT with and without LVH was observed. Diastolic left ventricular compliance evaluated by early to late transmitral flow velocity ratio (E/A ratio) significantly declined from normotensive subjects to BHT with LVH. There was a significant positive correlation between E/A and SDNN and SDANN throughout all studied groups. This indicates that BHT with LVH has a reduced HRV compared to other groups. This impairment is probably related to left ventricular mass and left ventricular filling abnormalities.

Antihypertensive drugs and sympathetic nervous system

Several studies have demonstrated that essential hypertension is accompanied by sympathetic activation, which contributes to blood pressure elevation. Sympathetic activation also has adverse consequences in hypertensive patients beyond initiating blood pressure elevation. There is evidence that neural vasoconstriction has metabolic effects in skeletal muscle, impairing glucose delivery to muscles. In the liver, retarding of post prandial clearance of lipids contributes to hyperlipidemia. Cardiac sympathetic activation is a probable cause of sudden death in hearth failure. A trophic effect of sympathetic activation on cardiovascular growth is also likely, contributing to the development of left ventricular hypertrophy. Consequently, one of the major aims of antihypertensive therapy should be to attenuate sympathetic tone. It is possible that, among the antihypertensive drugs available, those inhibiting the sympathetic nervous system might best reduce cardiovascular risk.

Influence of insulin-like growth factor-1 and leptin on bone mass in healthy postmenopausal women

This study examines the influence of circulating insulin-like growth factor-1 (IGF-1) and serum leptin on bone mass as well as modulation of bone mass during skeletal development. Moreover, an inverse relationship between IGF-1 and leptin is reported. To evaluate the effects of serum IGF-1 and serum leptin on bone mass in healthy postmenopausal women, and the possible role of IGF-1 in leptin production, we studied a population of 123 women, aged 39-82 years. Bone mineral density (BMD) was determined by whole-body dual-energy X ray absorptiometry, which also enables measurement of body composition. Bone metabolism was assessed by measuring serum total alkaline phosphatase (TAP) and urinary hydroxyproline/creatinine (HP/Cr) excretion. IGF-1 correlated significantly with age (r = -0.28, p < 0.01) and years since menopause (r = -0.24, p < 0.01). A negative correlation was also found with weight and body mass index (r = -0.15, p < 0.05 and r = -0.19, p < 0.05, respectively). Leptin values were strongly correlated with weight (r = 0.7, p < 0.01), BMI (r = 0.7, p < 0.01), fat mass (r = 0.77, p < 0.01), and lean mass (r = 0.39, p < 0.01); a significant correlation was found with total body BMD (r = 0.29, p < 0.01), TAP (r = 0.15, p < 0.05), and HP/Cr (r = 0.18, p < 0.05). After adjustment for BMI, the significance of these relationships disappeared, demonstrating the lack of effect of serum leptin on BMD and bone turnover independent of body weight. On the other hand, the relationship between BMD and fat mass remained statistically significant after adjusting for serum leptin (r = 0.15, p < 0.05). Controlling for BMI eliminated the significant inverse correlation between IGF-1 and leptin; significant differences in leptin levels were found among women in the lower and higher quartile of IGF-1, suggesting that leptin production may be inhibited only at high values of serum IGF-1. We conclude that serum IGF-1 and serum leptin have no direct effect on bone mass and bone turnover.

Obesity and autonomic function in adolescence

Hypertension and obesity are risk factors for coronary heart diseases in adults. In turn, childhood overweight and high blood pressure increase the risk of subsequent obesity and hypertension in adulthood. Human obesity is characterized by profound alterations of hemodynamic and metabolic states. Whether these alterations involve sympathetic nervous system control on cardiac function is controversial. We report the results of our study, conducted in a sample of obese adolescents by using power spectral analysis of heart rate variability. An increase in sympathetic tone coupled with a reduction in vagal tone was found. This allowed us to hypothesize that autonomic nervous system changes depend on the time course of obesity development. It is still unclear if treatment of obesity in adolescence prevents subsequent autonomic imbalance and hypertension.

Electron spin resonance of copper(II) as a tool for the determination of asparagine concentration in Bacillus subtilis cultures

A procedure is presented that is based on the detection of Cu(II)-asparagine complexes by quantitative ESR, and allows in a very simple and rapid manner to evaluate the changes of asparagine concentration during the entire time range of the growth of Bacillus subtilis in a typical growth medium. The analysis is carried out in terms of the decrease of the intensity of the ESR-active mono- and di-asparagine copper(II) complexes. It is resulted that at the end of the exponential growth the asparagine concentration was reduced to values as low as 2% of the initial value. The procedure here reported may be the basis of similar methods to be used for other amino acids and prokaryote systems.

Hemolytic-uremic syndrome as a presenting form of acute lymphocytic leukemia

We report an 8-year-old girl who presented with hemolytic-uremic syndrome (HUS) as the onset manifestation of acute lymphocytic leukemia (ALL). The patient was admitted to the hospital for renal failure, thrombocytopenia, and anemia during a HUS outbreak. She was discharged 2 weeks later with normal renal function. One month later the girl presented with clinical and laboratory signs consistent with a diagnosis of ALL. The short time interval between HUS and ALL suggests that HUS was probably an early manifestation of acute leukemia.

Effectiveness and complications of vascular access closure devices after interventional procedures

BACKGROUND

Vascular closure devices are designed to obtain a fast hemostasis of the vascular access site after diagnostic and interventional procedures. This result should be obtained with a low incidence of complications.

METHODS

A retrospective, non-randomized study was performed to evaluate the success rate and vascular complications associated with the use of two different vascular sealing devices [Angio-Seal (Daig Corporation, Minnetonka, Minnesota) and Prostar (Perclose, Inc., Redwood City, California)] after interventional procedures.

RESULTS

Eight-hundred and twenty-seven devices were used (245 Angio-Seal and 582 Prostar). Angio-Seal success rate was 92% with a 2.5% rate of vascular complications; Prostar success rate was 89% with a 3.4% rate of vascular complications. Multivariate logistic regression analysis identified advanced age (p < 0.05) and lower weight (p < 0.05) as independent predictors of vascular complications associated with Angio-Seal use, while diabetes (p < 0.05) was found to be a predictor of vascular complications in the Prostar group. Abciximab use and larger sheath size were not associated with an increased probability of vascular complications.

CONCLUSION

Angio-Seal and Prostar obtain a fast vascular access hemostasis after interventional procedures, with a low incidence of major vascular complications.

Cu(II) complexes in bacterial growth medium: electron spin resonance study

In this study we report a spectroscopic investigation on the structure and stability of Cu(II)-complexes that are formed in a minimum growth medium (MM), normally used for Bacillus subtilis cultures. As other transition metals, Cu(II) compounds are toxic to this bacterium and the toxicity depends on the Cu(II) concentration. MM contained NH4+ ions and asparagine (asn) as the source of inorganic and organic nitrogen. Both ESR and electronic spectra demonstrated the very important role played by the amino acid asparagine in the coordinative behaviour of Cu(II). In particular, three different complexes were evidenced: Cu(H2O)6(2+); Cu(asn)+ and Cu(asn)2. The relative amount of these three species strongly depended on pH, on Cu:asn ratio and on the presence of the phosphate ions. They were identified and evaluated quantitatively by extensive simulation of the electron spin resonance (ESR) spectra recorded in different experimental conditions. The bis-complex was found to be more stable in MM than in an asparagine-containing water solution with the same Cu:asn ratio. A comparison of the spectroscopic results with microbiological investigations is also made.

Relationship between birth weight and blood pressure in adolescence

BACKGROUND

Several studies have found a relation ship between small size at birth and high blood pressure (HBP). However, this association has not been fully evaluated in adolescence. The aim of the present study was to evaluate the relation of birth weight (BW) to BP in adolescence, controlling for factors related to BP, to extrauterine environment, and to maternal risk of fetal distress.

METHODS

In 1310 adolescents (ages 12-14 years), randomly selected from Turin school children, we evaluated BP, heart rate (HR), weight, height, familial risk of hypertension, parental cultural level, BW, and maternal history of diseases during pregnancy. The BW-BP association was tested by using multiple regression analysis and adjusting for the other variables mentioned above. The same analysis was done for the subgroup at high risk of fetal distress.

RESULTS

The association between BW and BP was negative but weak when we adjusted for all confounders (= -0.07 in males; = -0.27 in females). The association was negative and became stronger after the inclusion of all confounders, particularly HR (= -3.92), in the group of children at high risk of fetal distress.

CONCLUSIONS

Intrauterine environment, as reflected by BW, has little effect on BP in early adolescence without concomitant maternal diseases or environmental conditions leading to severe placental hypoperfusion.

Nitroxides and malignant human tissues: electron spin resonance in colorectal neoplastic and healthy tissues

Healthy and neoplastic colorectal human tissues of as many as 12 patients have been studied, immediately after surgery, by electron spin resonance (ESR) of stable nitroxides at physiological temperature. Cells were maintained in a living state using the McCoy's 5A culture medium. The very low concentration changes of hydrophilic and lipophilic nitroxides allowed us to establish that the response to the oxidative stress induced by the occurrence of nitroxides in healthy and tumor cells was very weak, thus suggesting these compounds are good candidates for contrast enhancement agents in magnetic resonance imaging of colorectal tumor. The analysis of the computed ESR line shape of lipophilic nitroxides in both healthy and malignant cells of the same patient agreed for an unmodified physical status of the membranes where they were mainly localized. The results reported here proved that the comparison between ESR results must be made in tissues from the same patient and that the physical status of the membranes depended more on the patient history than on changes in the colorectal cell membrane fluidity induced by the neoplastic process.

Impaired baroreflex function and arterial compliance in primary aldosteronism

The purpose of this study was to evaluate if changes in vascular properties were related to baroreflex function in patients with primary aldosteronism. Twenty-three patients with primary aldosteronism, 22 essential hypertensive patients and 16 normal controls were studied. Continuous finger blood pressure (BP) was recorded by Portapres device during supine rest and active stand up. Compliance was estimated from the time constant of pressure decay during diastole. Baroreflex sensitivity was calculated by autoregressive cross-spectral analysis of systolic BP and interbeat interval. The result was that baroreflex gain and compliance were lower in primary aldosteronism patients in the supine position (P = 0.002 and P < 0.05 respectively). Aldosterone plasma levels (R2 = 0.31, P = 0.01), age, systolic and diastolic BP, high and low frequency components of diastolic BP variability were independently related to compliance in primary aldosteronism. In conclusion primary aldosteronism is associated with an impaired baroreflex function related in part to a reduced arterial compliance. Despite a reduction of BP values and aldosterone levels, surgical or pharmacological treatment did not significantly change compliance values.

Noninvasive assessment of spontaneous baroreflex sensitivity in patients with liver cirrhosis

AIMS/BACKGROUND

An impairment of baroreceptor sensitivity has been found in liver cirrhosis. Noninvasive and spontaneous estimates of baroreflex sensitivity are obtained from beat-to-beat blood pressure and heart rate recordings by means of cross-spectrum analysis and calculation of alpha-index (as a measure of baroreflex gain). The aim of the present study was to investigate the function of the spontaneous baroreflex sensitivity related to clinical Child score in liver cirrhosis.

METHODS

The alpha-index was evaluated in 40 cirrhotic patients (18 with and 22 without ascites) and 17 healthy subjects by analysing finger arterial pressure recorded noninvasively with the Portapres device.

RESULTS

Baroreflex sensitivity was significantly lower in cirrhotic patients with and without ascites compared with healthy subjects (p<0.01). Furthermore, in patients with ascites the baroreflex gain was significantly related to plasma sodium (p<0.01). A significant inverse relationship was present between baroreflex gain and grade of Child score and the severity of ascites (p<0.01). There were no significant relationships between hormonal parameters (catecholamines, renin, aldosterone, arginine-vasopressin, atrial natriuretic peptide and nitric oxide) and baroreflex gain. No significant differences were found between healthy subjects and cirrhotic patients with respect to systolic and diastolic blood pressure total variability in a supine position, whilst it was lower in cirrhotic patients with ascites in a tilted position (p<0.05).

CONCLUSION

Our findings showed that baroreflex sensitivity was significantly impaired in cirrhotic patients when compared with healthy subjects. In addition, there was a significant trend toward lower baroreflex sensitivity values with the grade score of Child class (p<0.01). Spectral analysis of the alpha-index provides viable alternatives to the pharmacological approach for estimation of baroreflex sensitivity and may represent a prognostic tool to identify cirrhotic patients at increased risk of adverse events.

Molecular anatomy of the human glucose 6-phosphate dehydrogenase core promoter

The gene encoding glucose 6-phosphate dehydrogenase (G6PD), which plays a pivotal role in cell defense against oxidative stress, is ubiquitously expressed at widely different levels in various tissues; moreover, G6PD expression is regulated by a number of stimuli. In this study we have analyzed the molecular anatomy of the G6PD core promoter. Our results indicate that the G6PD promoter is more complex than previously assumed; G6PD expression is under the control of several elements that are all required for correct promoter functioning and, furthermore, a still unidentified mammalian specific factor is needed.

Stability of water-soluble and lipid-soluble paramagnetic probes in Bacillus subtilis

Batch cultures of the Gram-positive bacterium Bacillus subtilis PB19 have been investigated for their metabolic action to electron spin resonance (ESR) probes. Five- and six-membered water-soluble and lipid-soluble nitroxides have been used, which were reduced most probably to the corresponding hydroxylamine derivatives. The reduction was followed by the ESR signal intensity and found to be dependent on chemical structure and stability, lipophilic/hydrophilic character, charge, concentration, and temperature. Water-soluble nitroxides did not show apparent toxicity towards B. subtilis, in contrast with n-DXSA (n=5, 12, 16) which were found to be strongly cytotoxic. The cytotoxicity depended on the position of the doxyl unit along the hydrocarbon chain. The hydrophilic nitroxides were reduced at a much slower rate relative to the lipophilic ones. Membrane diffusion was suggested to be a slower process relative to chemical reduction for water-soluble nitroxides. The lipophilic nitroxides were solubilized into the membrane where they were rapidly reduced with a reduction maximum at 303-310 K, which is the optimal growth temperature of B. subtilis, while an inactivation at higher temperatures was observed. Both toxicity and reduction rates of nitroxides strongly indicated that the reduction was an enzyme-mediated process taking place near the outer surface of the periplasmic membrane.

Central diabetes insipidus with spontaneous remission. A case report

We report a case of central diabetes insipidus with spontaneous remission 8 months after clinical beginning of the disease. A 20 years-old man developed polydipsia and polyuria in October 1994. A water deprivation study showed a defect in the urine concentrating function, which was corrected by vasopressine. A Magnetic Resonance imaging of the skull revealed a thickening of the pituitary stalk. His condition was well controlled by nasal DDAVP administration and 6 months later patient reduced spontaneously medication dose without clinical worsening. 8 months after clinical beginning, patient has become completely free from the need for medication to control clinical symptoms and urine concentrating function, as demonstrated by a re-evaluation study with water deprivation. A control Magnetic Resonance showed the regression of stalk enlargement. The clinical and radiological features of this case are discussed.