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Biomedical subjects

A Lombardo

Publications and source records attributed to A Lombardo.

At least 19 recordsLinked to original sources
PubMed2006

Erythrocyte glycohydrolases in subjects with trisomy 21: could Down's syndrome be a model of accelerated ageing?

We studied some erythrocyte glycohydrolases, erythrocyte membrane fluidity, plasma hydroperoxides and total antioxidant defences in 23 Down syndrome (DS) individuals in comparison with healthy age-matched and elderly controls. With regard to erythrocyte plasma membrane fluidity, plasma hydroperoxides and total plasma oxidative defences, DS subjects resembled the age-matched controls more than the elderly ones. Membrane glycohydrolases in DS, however, presented a pattern partly similar to age-matched controls and partly to elderly controls. Concerning cytosol glycohydrolases, DS subjects had lower levels of hexosaminidase and N-acetyl-beta-D-glucosaminidase, the latter specific for the hydrolysis of GlcNAc residues O-linked to proteins. In general, erythrocyte membrane and cytosol glycohydrolases decreased during erythrocyte ageing in DS subjects and in all controls. The increased levels of the same enzymes in DS plasma might be attributed to an alteration of their release-uptake mechanisms between the two different compartments, on account of the higher plasma hydroperoxide levels. These findings indicate that erythrocyte ageing in DS differs partially from that of age-matched and elderly controls. In any case, the accelerated ageing seen in DS is no fully comparable to physiological ageing.

Adolescent↗
PubMed2006

Limited transgene immune response and long-term expression of human alpha-L-iduronidase in young adult mice with mucopolysaccharidosis type I by liver-directed gene therapy.

Mucopolysaccharidosis type I (MPS I) due to deficient alpha-L-iduronidase (IDUA) activity results in the accumulation of glycosaminoglycans (GAGs) in many of the cells of affected patients. Stable gene replacement by in vivo administration of lentiviral vectors (LVs) has therapeutic potential for metabolic disorders and other systemic diseases. We have previously shown in a murine model the therapeutic potential of lentiviral IDUA vector-mediated gene therapy, in which human IDUA cDNA was driven by the cytomegalovirus promoter. However, the major limitation of this approach was the induction of an immune response against the therapeutic protein, which limited the efficacy and long-term duration of treatment. In this study, we evaluate the potential of liver-directed gene therapy, that is, programming of murine hepatocytes to secrete the enzyme with mannose 6-phosphate (M6P), which can be taken up by distant cells. Eight- to 10-week-old mice were injected via the tail vein with a lentiviral vector expressing human IDUA cDNA driven by the albumin gene promoter selectively expressed in hepatocytes. One month after treatment, IDUA activity was present in the liver and spleen of treated mice; an expression level of 1% normal IDUA activity was sufficient to reduce the GAG level in liver, spleen, kidney, heart, and lung. Interestingly, 6 months after a single injection of this vector, IDUA activity was detectable in several murine tissues; the level of enzyme activity was low but sufficient to maintain the decrease in GAG levels in liver, spleen, kidney, heart, and lung. Also, the level of enzyme-specific antibodies reached at 6 months postinjection was nearly null, and real-time polymerase chain reaction analysis showed high levels of vector DNA content in liver and spleen. Thus, these results show that the use of LV with the albumin gene promoter selectively expressed in hepatocytes limited the immune response to the transgene and allowed stable and prolonged expression of the IDUA enzyme and a partial correction of the pathology.

Animals↗
PubMed2005

Erythrocyte membrane alterations during ageing affect beta-D-glucuronidase and neutral sialidase in elderly healthy subjects.

In this study, a comparison between elderly (>70 years) and young subjects reveals that elder people are subject to a higher oxidative stress, which causes an increase in plasma hydroperoxide levels (18%) and a decrease in antioxidant defenses (25%). Moreover, the marked decrease of the erythrocyte membrane fluidity observed in elderly subjects was likely to affect the behavior of some membrane glycohydrolases. In fact, a significant decrease of beta-d-glucuronidase and neutral sialidase (30 and 50%, respectively) was detected. Activity differences were also observed when erythrocytes were further distinguished according to their biological age. Striking differences between young and elderly subjects were observed for beta-d-glucuronidase and neutral sialidase in young and senescent erythrocytes, respectively. Overall beta-d-glucuronidase decreases with the subjects' age, while neutral sialidase levels are higher in the elderly. This is presumably due to the localization of these enzymes in distinct plasma membrane micro-domains, which are differently peroxidized. A possible role of these enzymes in signaling praecox membrane alterations has also been evidenced.

Adult↗
PubMed2005

Improvement of stress LVEF rather than rest LVEF after coronary revascularisation in patients with ischaemic cardiomyopathy and viable myocardium.

OBJECTIVE: To evaluate prospectively the response of left ventricular ejection fraction (LVEF) to high dose dobutamine infusion in patients showing substantial viability, with and without improved resting LVEF after revascularisation. METHODS: Before and 9-12 months after revascularisation, 50 patients with ischaemic cardiomyopathy (LVEF 32 (8)%) and substantial myocardial viability (> or = 4 viable segments) underwent radionuclide ventriculography and dobutamine stress echocardiography. Patients were divided into group 1, patients with, and group 2, patients without significant improvement in resting LVEF (> or = 5% by radionuclide ventriculography) after revascularisation. The response of LVEF during dobutamine stress echocardiography was compared in these two groups. RESULTS: Groups 1 and 2 were comparable in baseline characteristics, resting LVEF, and number of viable segments (mean (SD) 7 (4) v 6 (2), not significant). After revascularisation, the LVEF response during dobutamine stress echocardiography improved significantly in both groups (group 1, 34 (10)% to 56 (8)%; group 2, 32 (10)% to 46 (11)%; both p < 0.001). Interestingly, although resting LVEF did not improve in group 2, peak stress LVEF after revascularisation did (p < 0.001). Group 1 patients had, however, a greater increase in peak stress LVEF (group 1, 22 (10)%; group 2, 13 (9)%; p < 0.01). New York Heart Association and Canadian Cardiovascular Society classes decreased in both groups. CONCLUSIONS: Although patients with viable myocardium did not always have improved rest LVEF after revascularisation, peak stress LVEF improved. Assessment of improvement of resting function may not be the ideal end point to evaluate successful revascularisation.

Blood Pressure↗
PubMed2003

Spectrum of clinical variability in familial deletion 22q11.2: from full manifestation to extremely mild clinical anomalies.

The 22q11.2 deletion (del22q11.2) syndrome is a genetic condition with wide interfamilial and intrafamilial variability in clinical expression. The aim of the present study was to review the prevalence of parental transmission in our series of patients with del22q11.2, and to analyse clinical findings of the affected parents. Parental transmission of del22q11.2 in our series was 17.2% (15/87), with a preferential maternal transmission (10/15). One or more major features of del22q11.2 were found in all deleted parents, but one of the mothers showed extremely mild clinical anomalies. The present data demonstrate that it should be current policy to test both parents of patients with del22q11.2, irrespective of the parental phenotype, in view of the fact that extremely mild clinical features can be detected in parents of deleted patients. This would provide accurate genetic counselling to del22q11.2 families, as relatively asymptomatic parents must be advised of the 50% risk of transmitting the deletion in a subsequent pregnancy. Various genetic and non-genetic factors, including modifier genes at separate loci, mosaicism, unstable mutations, allelic variations at the haploid locus, chance and environmental interaction, can be hypothesized to be involved in variable clinical expression, even in the same family.

Chromosomes, Human, Pair 22↗
PubMed2003

Temporal evolution and functional outcome of no reflow: sustained and spontaneously reversible patterns following successful coronary recanalisation.

OBJECTIVE: To identify in humans the temporal patterns of no reflow and their functional implications. METHODS: 24 patients with first acute myocardial infarction and successful coronary recanalisation by recombinant tissue-type plasminogen activator (n = 15) or primary percutaneous transluminal coronary angioplasty (n = 9) were studied by myocardial contrast echocardiography within 24 hours of recanalisation and at one month's follow up. Myocardial contrast echocardiography was performed by intermittent harmonic power Doppler and intravenous Levovist. The regional contrast score index (CSI) was calculated within dysfunctioning myocardium. Videointensity was measured (dB) within risk and control areas and their ratio was calculated. RESULTS: In 8 patients reflow was observed at 24 hours and persisted at one month. Conversely in 16 patients areas of no reflow were detectable at 24 hours. At one month, no reflow was spontaneously reversible in 9 patients (mean (SD) CSI and videointensity ratio improved from 2.5 (0.5) to 1.4 (0.6) and from 0.6 (0.1) to 0.7 (0.1), respectively; p < 0.05) and was sustained in the remaining 7 patients (CSI and videointensity ratio remained unchanged from 2.6 (0.6) to 2.6 (0.5) and from 0.5 (0.2) to 0.5 (0.2), respectively; NS). Left ventricular function improved significantly in patients with reflow and reversible no reflow. Volumes were enlarged only in patients with sustained no reflow. CONCLUSIONS: No reflow detected at 24 hours may be sustained or spontaneously reversible at one month. Such reversibility of the phenomenon is associated with preserved left ventricular volumes and function. Clarification of the mechanisms of delayed reversibility may lead to tailored treatment of no reflow even in the subacute phase of myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed2002

Efficient gene delivery and targeted expression to hepatocytes in vivo by improved lentiviral vectors.

Safe and efficient genetic modification of liver cells could enable new therapies for a variety of hepatic and systemic diseases. Lentiviral vectors are promising tools for in vivo gene delivery. Previous data suggested that recruitment into the cell cycle was required for transduction of hepatocytes in vivo. We developed an improved vector design that enhanced nuclear translocation in target cells and significantly improved gene transfer performance. Using the new vector and a panel of internal promoters, we showed that rat hepatocytes were transduced ex vivo to high frequency without requirement for proliferation. On intravenous administration of vector into adult severe combined immunodeficient (SCID) mice, we found high levels (up to 30%) of transduction of parenchymal and nonparenchymal cells of the liver, integration of the vector genome in liver DNA and stable expression of the marker green fluorescent protein (GFP)-encoding gene without signs of toxicity. Coadministration of vectors and 5'-bromo-2'-deoxyuridine in vivo proved that cell cycling was not required for efficient transduction of hepatocytes. In addition to the liver, the spleen and the bone marrow were transduced effectively by systemic delivery of vector. GFP expression was observed in all these organs when driven by the cytomegalovirus promoter and by the phosphoglycerate kinase gene promoter. Using the promoter of the albumin gene, we could restrict expression to hepatocytes. By a single vector injection into the bloodstream of SCID mice, we achieved therapeutic-range levels of the human clotting factor IX, stable in the plasma for up to 1 year (the longest time tested), indicating the potential efficacy of improved lentiviral vectors for the gene therapy of hemophilias and other diseases.

Animals↗
PubMed2001

Abdominal B-type Hox gene expression in Xenopus laevis.

We have studied the expression of the Abdominal B-type Hox genes in Xenopus embryos and tadpoles. The probes used represent all paralog groups and are designated Xhoxa9, Xhoxd9, Xhoxd10, Xhoxa11, Xhoxc12 and Xhoxa13 on the basis of comparison to other vertebrates. Three of these genes are novel while the others have previously been detected but expression patterns were only partially described. We find a typical nested pattern of expression in the main body axis, in both central nervous system and mesoderm. All the genes, except Xhoxc12, are also expressed in the mesenchyme of the large intestine and in the limb buds.

Animals↗
PubMed2000

Neuroadrenergic activation and response to dobutamine in congestive heart failure secondary to idiopathic dilated cardiomyopathy.

Detection of contractile reserve is important in heart failure patients. To determine if detection of contractile reserve is influenced by neuroadrenergic activation, we examined the relation between dobutamine stress echocardiography (DSE) findings and plasma norepinephrine levels (NE) at rest in 35 patients with nonischemic left ventricular (LV) dysfunction (New York Heart Association class >III in all; LV ejection fraction 0.27 +/- 0.5). Changes in global wall motion score (WMS), and separately in WMS of hypokinetic segments and akinetic segments, were analyzed. A patient was considered to be responsive to dobutamine if the change in global WMS was >/=4. Twenty-three patients were responsive and 12 were not responsive to dobutamine. Plasma NE and baseline heart rate were significantly higher in nonresponsive patients (p <0.001). Changes in global WMS and in hypokinetic segment WMS were inversely related to either plasma NE (r -0.68 and -0.67, respectively) or baseline heart rate (r -0.60 and -0.66, respectively). The change in akinetic segment WMS was related to plasma NE only (r -0.50). Changes in WMS were not related to age, diastolic and systolic LV volume, baseline global WMS, or number of akinetic segments at baseline. Plasma NE >602 pg/ml predicted a blunted or absent contractile reserve at DSE (sensitivity 92%; specificity 87%). Neuroadrenergic activation may influence contractile reserve found at DSE in patients with heart failure due to nonischemic LV dysfunction.

Adult↗
PubMed2000

Membrane anchoring and surface distribution of glycohydrolases of human erythrocyte membranes.

The membrane anchoring of the following glycohydrolases of human erythrocyte plasma membranes was investigated: alpha- and beta-D-glucosidase, alpha- and beta-D-galactosidase, beta-D-glucuronidase, N-acetyl-beta-D-glucosaminidase, alpha-D-mannosidase, and alpha-L-fucosidase. Optimized fluorimetric methods for the assay of these enzymes were set up. Treatment of the ghost preparation with 1.0 mol/l (optimal concentration) NaCl caused release ranging from 4.2% of alpha-D-glucosidase to 70% of beta-D-galactosidase; treatment with 0.4% (optimal concentration) Triton X-100 liberated 5.1% of beta-D-galactosidase to 89% of alpha-D-glucosidase; treatment with 1.75% (optimal concentration) octylglucoside yielded solubilization from 6.3% of beta-D-galactosidase to 85% of alpha-D-glucosidase. Treatment with phosphoinositide-specific phospholipase C caused no liberation of any of the studied glycohydrolases. These results are consistent with the notion that the above glycohydrolases are differently anchored or associated with the erythrocyte plasma membrane, and provide the methodological basis for inspecting the occurrence of these enzymes in different membrane microdomains.

Adult↗
PubMed2000

Plasma glycohydrolase levels in patients with type 1 diabetes at onset and in subjects undergoing an intravenous glucose tolerance test.

The effect of hyperglycemia and insulin deficiency on the plasma level of lysosomal glycohydrolases, namely N-acetyl-beta-D-glucosaminidase, beta-D-glucuronidase, alpha-D-galactosidase, and alpha-D-glucosidase, was investigated. Two patient groups were assessed: (1) 28 children with type 1 diabetes at onset (fasting blood glucose, 444+/-154 mg/100 mL; hemoglobin A1c, 11.9%+/-2.4%; symptom duration, 15.9+/-8 days; and absence of complications), (2) 14 adult subjects undergoing an intravenous glucose tolerance test (IVGTT), consisting of 8 non-obese subjects (body mass index, 26+/-0.04 kg/m2; fasting blood glucose, 82+/-13 mg/100 mL; blood insulin, 6+/-0.04 mU/L) and 6 obese subjects (fasting blood glucose, 97+/-3.5 mg/100 mL; blood insulin, 27+/-6 mU/L, with normal oral glucose tolerance test). Enzyme activity was determined with the fluorimetric method. The mean level of all evaluated enzymes was significantly increased in patients with type 1 diabetes at diagnosis compared with normal controls. Increased enzyme levels were also detected in the group of adults undergoing an IVGTT in whom hyperglycemia was accompanied by insulin resistance (ie, obese subjects). Glycohydrolase abnormalities appear to be related to insulin deficiency rather than hyperglycemia. Lysosomal apparatus abnormalities seem to be an inherent feature of diabetes that is present at disease onset. The possible role of insulin in the regulation of plasma glycohydrolase levels is discussed.

Adolescent↗
PubMed1999

Central pulmonary artery lesions in chronic obstructive pulmonary disease: A transesophageal echocardiography study.

BACKGROUND: In patients with acute pulmonary embolism, transesophageal echocardiography (TEE) often reveals presumably thrombotic lesions within the central pulmonary arteries (CPAs). These CPA lesions, when found in patients with primary pulmonary hypertension, have been attributed to in situ thrombosis or atherosclerosis. We hypothesized that similar CPA lesions may also develop in patients with chronic obstructive pulmonary disease (COPD) in the absence of pulmonary embolism. METHODS AND RESULTS: We examined by TEE 25 patients with COPD and 27 control patients with left heart disease. None of the patients had previous pulmonary embolism or ileofemoral and popliteal vein thrombosis. By use of TEE, CPA lesions were found in 12 COPD patients (48%) and 2 control patients (7.4%) (P<0.01). When CPA lesions were subdivided into types 1 (protruding and mobile) and 2 (wall-adherent), type 1 lesions proved to be uncommon, being found within the pulmonary trunk in 12% and 3.7% of COPD and control patients, respectively (P=NS). Conversely, type 2 lesions, which were always localized in the right pulmonary artery, were frequent in COPD patients (36%) and rare in control patients (3.7%) (P<0.01). When available, helical CT and MR angiography confirmed TEE findings, supporting an atherosclerotic origin of type 2 lesions, which were different from typical thrombotic lesions. FEV(1)/FVC ratio, RV/TLC ratio, PaO(2), hematocrit value, and pulmonary artery systolic pressure were not significantly different in COPD patients with and without CPA lesions. At TEE, however, COPD patients with CPA lesions showed a larger size of the main and right pulmonary arteries. CONCLUSIONS: TEE often reveals CPA lesions in stable patients with COPD even in the absence of significant pulmonary hypertension and not in close relation with the severity of pulmonary dysfunction.

Aged↗
PubMed1999

Alterations in the activity of several glycohydrolases in red blood cell membrane from type 2 diabetes mellitus patients.

The erythrocyte membrane in 71 patients with type 2 diabetes mellitus was assessed for glycohydrolase activity: N-acetyl-beta-D-glucosaminidase, beta-D-glucuronidase, alpha- and beta-D-galactosidase, alpha- and beta-D-glucosidase, alpha-D-mannosidase, and alpha-L-fucosidase. Only beta-D-glucuronidase, alpha-D-glucosidase, and beta-D-glucosidase showed markedly elevated levels with respect to the controls regardless of the presence of complications. Among the examined patients, those with good metabolic control (not yet submitted to any therapy) showed the same enzyme levels as the reference subjects, while the levels in patients with unsatisfactory metabolic control (treated with oral hypoglycemic and/or insulin) significantly differed from the control levels. For alpha-D-glucosidase and beta-glucosidase, a correlation with glycemia and the parameters of metabolic control was also evidenced. Alterations of beta-D-glucuronidase, alpha-D-glucosidase, and beta-D-glucosidase were also ascertained in the plasma of the same diabetic patients according to the literature; each enzyme correlated with the other, either in plasma or in the erythrocyte membrane. This study shows a correlation between plasma and erythrocyte membrane levels for these three enzymes. The strict parallelism of the glycohydrolases in the two different compartments provides a profile of these enzymes in the pathology of diabetes.

Blood Glucose↗
PubMed1998

Risk stratification of patients undergoing peripheral vascular revascularization by combined resting and dipyridamole echocardiography.

Patients with advanced peripheral vascular disease have an increased cardiac morbidity and mortality. The aim of this study was to assess the predictive value of rest and stress echocardiography for perioperative and late cardiac events in 110 patients undergoing limb revascularization. All patients underwent preoperative clinical and echocardiographic evaluation at rest and by dipyridamole stress testing to assess cardiac risk. Patients with > or =3 clinical Eagle markers, low left ventricular ejection fraction at rest, or positive dipyridamole stress test results were considered at high cardiac risk. To record adverse cardiac events, all patients were monitored during and after surgery, and followed for at least 1 year after hospital discharge. Cardiac complications occurred in 10 patients (9.7%) perioperatively (2 fatal myocardial infarctions), and in 13 (13%) at 1-year follow-up (7 fatal myocardial infarctions). Echocardiographic evaluation was the best predictor of early (p <0.00003) and late (p <0.0003) cardiac complications. No patient with a negative dipyridamole stress test result and good left ventricular ejection fraction had cardiac complications, either postoperatively or during follow-up. Clinical evaluation does not appear sufficiently sensitive for predicting perioperative cardiac events, but was valuable in predicting late cardiac complications (p <0.0002). Our data show that echocardiographic evaluation of resting dysfunction and of the ischemic response to dipyridamole is a good predictor of perioperative cardiac risk, and is superior to generally available clinical data. Echocardiographic evaluation is useful in defining a low-risk group of patients who can safely undergo limb revascularization, whichever surgical procedure is proposed.

Aged↗
PubMed1998

Postgastrulation effects of fibroblast growth factor on Xenopus development.

We have investigated postgastrulation functions of FGFs in Xenopus development by the implantation of heparin beads soaked in FGF2 to various positions at various stages. Anterior implantations show different effects depending on whether they are made to early neurulae or to later stages. At stage 13-14 there is a total or partial suppression of anterior structures including the forebrain, eyes, and midbrain. From stage 15 onwards there is no loss of anterior parts but there is a change in the structure of the eye such that the neural retina remains continuous with the wall of the diencephalon and the territories normally forming the optic stalk and pigment epithelium instead become neural retina. Posterior implantations cause a disruption of somite segmentation without affecting the differentiation of muscle cells. This is associated with a prolongation of the uniform expression of X-Delta-2 during the phase of segmental determination. There is also an induction of ectopic otocysts, which can lie either ipsilateral or contralateral to the FGF-bead. The results are discussed in terms of the known late expression domains of the various Xenopus FGFs, and of the late functions of FGFs in higher vertebrates. They provide new evidence for a role of endogenous FGFs in the development of the eye, somites, and otocysts.

Animals↗
PubMed1998

Lysosomal enzymes in preterm infants with bronchopulmonary dysplasia: a potential diagnostic marker.

Some lysosomal glycohydrolases (N-acetyl-beta-D-glucosaminidase and their major isoenzymes, beta-D-glucuronidase, alpha-D-galactosidase, beta-D-galactosidase and alpha-D-glucosidase) were investigated in the plasma of 36 preterm infants with respiratory distress, 11 of whom developed bronchopulmonary dysplasia (BPD), in order to evaluate the role of the lysosomal apparatus in the disease. Enzyme activity was assayed fluorimetrically; the major N-acetyl-beta-D-glucosaminidase (NAG) isoenzymes were separated using a routine chromatofocusing procedure; the diagnostic efficiency was evaluated by Bayes theorem. The mean levels of almost all glycohydrolases considered were significantly higher in BPD than in non-BPD infants. Among NAG major isoenzymes, an increase was found only in form A. No variation was evident in the plasma levels of glycohydrolases during dexamethasone therapy. Data from a retrospective analysis performed in all preterms considered, show that alpha-D-galactosidase and beta-D-galactosidase differentiate a posteriori BPD and non-BPD subjects. These enzymes, after a priori verification of their diagnostic potential in preterm infants at risk of BPD development, could acquire an important predictive value.

Biomarkers↗