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Biomedical subjects

M Rossi

Publications and source records attributed to M Rossi.

At least 73 records · Page 4Linked to original sources

Maternal apo E genotype is a modifier of the Smith-Lemli-Opitz syndrome.

BACKGROUND: Smith-Lemli-Opitz syndrome (MIM 270400) is an autosomal recessive malformation and mental retardation syndrome that ranges in clinical severity from minimal dysmorphism and mild mental retardation to severe congenital anomalies and intrauterine death. Smith-Lemli-Opitz syndrome is caused by mutations in the Delta7 sterol-reductase gene (DHCR7; EC 1.3.1.21), which impair endogenous cholesterol biosynthesis and make the growing embryo dependent on exogenous (maternal) sources of cholesterol. We have investigated whether apolipoprotein E, a major component of the cholesterol transport system in human beings, is a modifier of the clinical severity of Smith-Lemli-Opitz syndrome. METHOD: Common apo E, DHCR7, and LDLR genotypes were determined in 137 biochemically characterised patients with Smith-Lemli-Opitz syndrome and 59 of their parents. RESULTS: There was a significant correlation between patients' clinical severity scores and maternal apo E genotypes (p = 0.028) but not between severity scores and patients' or paternal apo E genotypes. In line with their effects on serum cholesterol levels, the maternal apo epsilon2 genotypes were associated with a severe Smith-Lemli-Opitz syndrome phenotype, whereas apo E genotypes without the epsilon2 allele were associated with a milder phenotype. The correlation of maternal apo E genotype with disease severity persisted after stratification for DHCR7 genotype. There was no association of Smith-Lemli-Opitz syndrome severity with LDLR gene variation. CONCLUSIONS: These results suggest that the efficiency of cholesterol transport from the mother to the embryo is affected by the maternal apo E genotype and extend the role of apo E and its disease associations to modulation of embryonic development and malformations.

Alleles↗

Pulmonary aspergillosis with possible cerebral involvement in a previously healthy pregnant woman.

UNLABELLED: Invasive aspergillosis is observed mainly in immunodepressed patients. Here we report a case of pulmonary aspergillosis with CNS involvement in a pregnant woman without other known causes of immunodeficiency. CASE REPORT: A 23-years old pregnant woman underwent a caesarean because of unexplained seizures. During the subsequent days worsening headache and a deteriorating neurological status were reported suggesting meningitis. Stiffness, right sided hemiparesis and cranial nerve palsies were observed at admission. Radiological findings revealed lesions involving the right pulmonary apex, the right cerebellar hemisphere and the Pterygopalatina fossa. Microbiological studies revealed large colonies of Aspergillus fumigatus. A favorable outcome was observed after administration of liposomal amphotericin B and 5-fluorocytosine and, at improved conditions, when oral uptake of itraconazole was given. The authors conclude that risk of infections sustained by fungal opportunistic agents during pregnancy must be considered. Sequential antifungal administration may be an efficient therapy able to shorten hospitalization.

Adult↗

Bone mass evaluated by calcaneous ultrasound and radial peripheral computed tomography in 726 youngsters.

AIM: To compare the results of ultrasound and computed peripheral tomography in evaluating bone mass in a population of normal children. METHODS: Seven hundred and twenty-six healthy school children (260 males; age 8.3-20.9 y) underwent calcaneous ultrasound and peripheral computed tomography at the ultradistal radius. Broadband ultrasound attenuation (BUA) and areal and volumetric bone mineral density (aBMD and vBMD) were evaluated. The results were compared and correlated among them and with auxological parameters (height, BMI and pubertal stages) using the software package SPSS for Windows. RESULTS: The three variables examined (BUA, aBMD and vBMD) all showed a progressive increase with age and a positive correlation with age, height and BMI. When the population was subdivided according to pubertal stages, all variables showed a progressive increase, the difference being significant when stages 1-2 were compared with stages 4-5. A significant correlation was present among BUA, aBMD and vBMD even if the Pearson correlation coefficient was not high. CONCLUSIONS: The similar pattern of BUA, aBMD and vBMD with respect to age, height and pubertal stages indicates that ultrasound could be a reliable method to screen bone mass abnormalities in children. The low correlation coefficient, however, suggests that the methods employed measure different bone parameters. Moreover, the different skeletal locations could also account for these results.

Adolescent↗

Spectral analysis of skin laser Doppler blood perfusion signal during cutaneous hyperemia in response to acetylcholine iontophoresis and ischemia in normal subjects.

Spectral analysis of skin laser Doppler (LD) signal was performed using Fourier transformation in twelve healthy subjects in order to compare post-ischemic hyperemia and acetylcholine (ACh) iontophoresis tests for the exploration of cutaneous microcirculatory endothelial function. Within the frequency range studied of 0.009-1.6 Hz, five different frequency intervals were considered, arising from local (endothelial and myogenic) and central (neural, respiratory and cardiac) regulatory mechanisms. The power density (PD) for each of the five frequency intervals considered was measured in perfusion units (PU)/Hz, in each subject, before and in response to ischemia and to ACh iontophoresis, using a dedicated software. The relative contribution of each frequency interval was calculated as per cent rate between each PD and the sum of the PD of the five frequency interval considered. PD of LD signals in response to ischemia and Ach iontophoresis significantly increased for all the five frequency intervals considered. A significant increase (from 25.0+/-6.3 to 48.3+/-17.8; p<0.01) in the relative contribution of 0.009-0.02 frequency interval, referred to endothelium activity, was observed only in response to ACh iontophoresis. No significant increase in the relative power contribution was observed in response to ischemia for any of the five frequency intervals considered. These data suggest that ACh iontophoresis test is more adequate than post-ischemic hyperemia test in exploring the skin microcirculatory endothelial function in normal subjects.

Acetylcholine↗

A novel extracellular subtilisin-like protease from the hyperthermophile Aeropyrum pernix K1: biochemical properties, cloning, and expression.

A novel extracellular serine protease designated Pernisine was purified to homogeneity and characterized from the archaeon Aeropyrum pernix K1. The molecular mass, estimated by SDS-PAGE analysis and by gel filtration chromatography, was about 34 kDa suggesting that the enzyme is monomeric. Pernisine was active in a broad range of pH (5.0-12.0) and temperature (60-120 degrees C) with maximal activity at 90 degrees C and between pH 8.0 and 9.0. In the presence of 1 mM CaCl(2) the activity, as a function of the temperature, reached a maximum at 90 degrees C but at 120 degrees C the enzyme retained almost 80% of its maximal activity. Activity inhibition studies suggest that the enzyme is a serine metalloprotease and biochemical data indicate that Pernisine is a subtilisin-like enzyme. The protease gene, identified from the sequenced genome of A. pernix, was amplified from total genomic DNA by PCR technique to construct the expression plasmid pGEX-Pernisine. The Pernisine, lacking the leader sequence, was expressed in Escherichia coli BL21 strain as a fusion protein with glutathione- S-transferase. The biochemical properties of the recombinant enzyme were found to be similar to those of the native enzyme.

Aeropyrum↗

Genomic distribution and characterization of EST-derived resistance gene analogs (RGAs) in sugarcane.

A large sugarcane EST (expressed sequence tag) project recently gave us access to 261,609 EST sequences from sugarcane, assembled into 81,223 clusters. Among these, we identified 88 resistance gene analogs (RGAs) based on their homology to typical pathogen resistance genes, using a stringent BLAST search with a threshold e-value of e(-50). They included representatives of the three major groups of resistance genes with NBS/LRR, LRR or S/T KINASE domains. Fifty RGAs showed a total of 148 single-dose polymorphic RFLP markers, which could be located on the sugarcane reference genetic map (constructed in cultivar R570, 2n=approximately 115). Fifty-five SSR loci corresponding to 134 markers in R570 were also mapped to enable the classification of the various haplotypes into homology groups. Several RGA clusters were found. One cluster of two LRR-like loci mapped close to the only disease resistance gene known so far in sugarcane, which confers resistance to common rust. Detailed sequence comparison between two NBS/LRR RGA clusters in relation to their orthologs in rice and maize suggests their polyphyletic origins, and indicates that the degree of divergence between paralogous RGAs in sugarcane can be larger than that from an ortholog in a distant species.

Amino Acid Sequence↗

Encapsulation of individual pancreatic islets by sol-gel SiO2: a novel procedure for perspective cellular grafts.

Pancreatic rat islets are encapsulated by a siliceous layer deposited on the surface of single islets upon reaction with gaseous siliceous precursors. The process preserves original islet dimensions and does not suppress viability or function. The encapsulated material is homogeneously distributed on the islet surface, and layer thickness can be controlled in the 0.1-2.0 microm interval. Dynamic perfusion experiments with glucose stimulation were carried out in both encapsulated and non-encapsulated islets. Results were treated according to a kinetic model presented here for the analysis of perfusion data; the model tested by literature data, was used to substantiate the diffusion features of the siliceous layer, which does not affect mass transfer of insulin but which modifies the texture of the islet surface tissue. The clinical potential of silica encapsulation was demonstrated by in vivo experiments using encapsulated islets transplanted into diabetic rats. Transplantation was carried out in both inbred and outbred rats and indicated prolonged restoration of normal glycaemia levels and protection from immunological attack.

Animals↗

Development of a genetic system for hyperthermophilic Archaea: expression of a moderate thermophilic bacterial alcohol dehydrogenase gene in Sulfolobus solfataricus.

The Escherichia coli/Sulfolobus solfataricus shuttle vector pEXSs was used as a cloning vehicle for the gene transfer and expression of two bacterial genes in Sulfolobus solfataricus. The alcohol dehydrogenase (adh) from the moderate thermophilic Bacillus stearothermophilus (strain LLDR) and a mutagenised version encoding a less thermostable ADH enzyme were the selected genes. S. solfataricus adh promoter and aspartate aminotransferase terminator were used to drive the heterologous gene expression and to guarantee the correct termination of the transcripts, respectively. The constructed vectors were found to be able to carry these 'passenger' genes without undergoing any rearrangements. The active transcription of bacillar mRNAs was ascertained in vivo by RT-PCR. Transformed S. solfataricus expressed functional exogenous ADHs that showed unaffected kinetic and chemical-physical features.

Alcohol Dehydrogenase↗

Use of antiparkinsonian drugs in the Umbria Region.

Discussion of differences between recommended guidelines and clinical practice is very useful in medicine. The use of a computerized database of all prescriptions of antiparkinsonian drugs enabled us to perform an epidemiological population-based study with low cost and in a relatively short time. We have identified 2 827 parkinsonian patients in November 2000 and estimate the number of patients taking dopaminoagonists aged >75 years, antidepressive drugs, and atypical neuroleptics.

Aged↗

Experimental study of stochastic noise propagation in SPECT images reconstructed using the conjugate gradient algorithm.

Thanks to an experimental study based on simulated and physical phantoms, the propagation of the stochastic noise in slices reconstructed using the conjugate gradient algorithm has been analysed versus iterations. After a first increase corresponding to the reconstruction of the signal, the noise stabilises before increasing linearly with iterations. The level of the plateau as well as the slope of the subsequent linear increase depends on the noise in the projection data.

Algorithms↗

A biochemical and immunological comparative study on Trypanosoma equiperdum and Trypanosoma evansi.

Trypanosoma equiperdum and Trypanosoma evansi were purified by three or four cycles of low-speed centrifugation and final filtration through DEAE cellulose. The purified trypanosomes were used in comparative biochemical and immunological studies. Comparative polypeptide pattern analysis revealed that T. equiperdum showed 21 polypeptide bands, whose Mr ranged from >200 to 14.8 kDa. T. evansi showed 25 polypeptide bands in the Mr range 97-14.8 kDa. The main differences were associated with the presence of secondary bands, relative intensity and the number of bands. Both species gave seven glycoprotein bands; those of 97 and 68 kDa were present in T. equiperdum but absent in T. evansi. Bands of 61 and 28 kDa were present in T. evansi but not in T. equiperdum. Anti-T. equiperdum sera recognized four homologous antigens and cross-reacted with three antigens of T. evansi. Anti-T. evansi sera recognized three homologous antigens and cross-reacted with four T. equiperdum antigens. Four identical proteolytic protease bands were present for both species, while only one surface protein was detected for each species: 66 kDa for T. equiperdum and 62 kDa for T. evansi.

Animals↗

Are vascular disorders more prevalent in the relatives of children and adolescents with migraine?

The objective of the study was to assess whether a family history of vascular disorders is more common in children and adolescents with migraine than in the general population. Family history of stroke, arterial hypertension, myocardial infarction and diabetes was investigated by history taking in relatives of ambulatory children and young adults with migraine and in a control group. The odds ratios (ORs) with 95% confidence intervals (95% CI) were used as a risk measure. Using univariate and multivariate (logistic regression) analysis, family history was assessed in the whole sample and in subgroups by sex and age, degree of relationship (parents and grandparents vs. relatives), disease type (migraine with and without aura), and type of vascular disorder. The sample included 143 cases (migraine with aura 35, migraine without aura 108) and 164 controls aged 3-24 years (mean 12 +/- 3.8 years). Patients with migraine were at increased risk of vascular disorders in parents and grandparents but not in all relatives. Multivariate analysis indicated family history of stroke as most common only in boys. In conclusion, our study provides some clues to the assumption that migraine and vascular disorders have common pathogenic mechanisms and that genetic susceptibility plays a role in increasing the risk of migraine in the offspring of families with one or more cerebrovascular or cardiovascular conditions.

Adolescent↗

Characterization of brain malformations in the Baraitser-Winter syndrome and review of the literature.

Baraitser-Winter syndrome is a rare autosomal recessive disorder characterized by developmental delay, dysmorphic features, and multiple malformations also involving the brain. We report a further case and provide updated information about an unrelated girl reported in the original paper by Baraitser and Winter. Both of them presented with pachygyria and the latter case was recently found to have subcortical band heterotopia on high resolution brain MRI imaging. These two patients and a review of the previously reported cases indicate that a specific pattern of brain anomalies falling in the agyria-pachygyria-band spectrum is associated with this dysmorphic syndrome, which may be considered another example of syndromic neuronal migration defect.

Abnormalities, Multiple↗

A new dehydrogenase specific towards aromatic aldehydes from a halophilic bacterium.

A new enzyme showing a dehydrogenase activity towards aromatic aldehydes was isolated, purified and characterized from a halophilic strain isolated from saline environment. The enzyme is a monomer of 54 kDa; it is rather thermostable (optimal temperature: 50 degrees C) showing a broad spectrum of activity in a large pH range with the maximum at pH 9.5. The substrate specificity and the effect of ions were evaluated and compared with analogous described proteins.

Aldehyde Dehydrogenase↗

[Emergencies in cardiac surgery: prophylaxis or correction?].

Management of coagulation during cardiac surgery is always challenging for the anesthesiologist, even in elective operations. The strict linkage between coagulation and inflammation is amplified during cardiopulmonary bypass due to the contact of the blood with the foreign surfaces. In emergencies, coagulative derangement could be worse but the cardiocirculatory instability and parenchimal failure often overcome the attention to this problem.

Anticoagulants↗

Atherosclerotic ischemic renal disease.

AIM: Atherosclerotic ischemic renal disease is a frequent cause of end-stage renal failure leading to dialysis among the elderly; its prevalence is inferred from autopsy or retrospective arteriographic studies. Screening investigation for ischemic nephropathy on large cohorts, based on non invasive diagnostic techniques, have not so far been published. This study has been conducted on 269 subjects over 50 with hypertension and/or chronic renal failure, unrelated to other known causes of renal disease. METHODS: All 269 patients were studied either by color-flow duplex sonography (n=238) or by renal scintigraphy (n=224), and 199 of the 269 patients were evaluated using both of these techniques. Forty patients, found to have renal artery stenosis, were subjected to 3D-contrast enhancement magnetic resonance angiography (MRA) and/or digital selective angiography (DSA). An additional 23 cases, negative both to scintigraphy and to ultrasound study, underwent renal angiography (MRA and/or DSA). RESULTS: Color-duplex sonography, carried out in 238 patients, revealed 49 cases of renal artery stenosis. MR or DSA was carried out in 35 of these 49 patients, and confirmed the diagnosis in 33. Color-duplex sonography was 91.7% sensitive and 90.9% specific, with positive predictive value of 94.2% and negative predictive value of 86.9%. Specificity and sensitivity of renal scintigraphy, carried out in 224 patients, was significantly lower. Patients with renal artery stenosis showed a higher degree of renal insufficiency compared to non stenotic patients while there were no differences in the extent of proteinuria between the two groups. Renal artery stenosis, based on color-duplex sonography studies, was present in 11% of patients in the age group 50-59, 18% in the 60-69 and 23% at age 70 and above. CONCLUSION: A relatively large percentage of the elderly population with renal insufficiency and/or hypertension is affected by renal artery stenosis and is at risk of developing end-stage renal failure. Color-duplex ultrasonography is a valid routine method of investigation of population at risk for renal artery stenosis.

Aged↗

A novel thermophilic fusion enzyme for trehalose production.

In recent years a number of hyperthermophilic micro-organisms of Sulfolobales have been found to produce trehalose from starch and dextrins. In our laboratory genes encoding the trehalosyl dextrin forming enzyme (TDFE) and the trehalose forming enzyme (TFE) of S. solfataricus MT4 have been cloned and expressed in E. coli (Rb791). Here we report the construction of a new protein obtained by fusion of TFE and TDFE coding sequences which is able to produce trehalose from dextrins at high temperature by sequential enzymatic steps. We demonstrate that the bifunctional fusion enzyme is able to produce trehalose starting from malto-oligosaccharides at 75 degrees C. Furthermore we partially purified the recombinant fusion protein from bacterial cell free extracts and from insoluble fractions in which the fusion protein was also found as aggregate in inclusion bodies.

Bacterial Proteins↗