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G Morelli

Publications and source records attributed to G Morelli.

At least 55 records · Page 3Linked to original sources
PubMed1998

The new EPR molecular oxygen probe fusinite is not toxic to cells.

The possible cytotoxic effects of fusinite, a new charcoal-like electron paramagnetic resonance (EPR) oxygen probe, were evaluated in three cell types with very different characteristics and growth features: K562 (an erythroleukemic cell line which grows in suspension), A431 (an epidermal carcinoma cell line which grows in monolayer) and primary cultures of murine fibroblasts (which also grow in adhesion culture) utilizing morphological and functional studies as well as growth analyses. Scanning and transmission electron microscopy as well as fluorescence microscopy were used for the morphological analyses while conductometric relaxation studies in the radiowave frequency range, membrane resistance measurements and adenine nucleotide levels were utilized for the more subtle functional evaluation of cell parameters. The results show that the presence of fusinite particles, even after long internalization times, does not induce any cytotoxic effects in the cells studied. Thus, from these results, it can be deduced that fusinite is non-toxic as well as highly stable, inert and very sensitive to oxygen, and can be used with great success for cell studies where determination of oxygen concentration is important.

Adenine Nucleotides↗
PubMed1998

Cytochemical localisation of the NADPH diaphorase activity in the Leydig cells of the mouse.

The distribution of the NADPH diaphorase activity was studied in mouse Leydig cells by means of light and electron microscopy. When observed by the light microscope, most Leydig cells appeared intensely stained; a few cells (about 10%) showed a slightly positive or apparently negative reaction. The inhibitory effects of N(G)-nitro-L-arginine and iodonium diphenyl on frozen sections suggest the colocalisation of NADPH diaphorase reaction with nitric oxide synthase. The ultrastructural study revealed that all the Leydig cells were positively stained for NADPH diaphorase; however, a small number of cells displayed weak enzymatic activity. The reaction product was located in the mitochondria, smooth endoplasmic reticulum and lipidic vacuoles, and the nuclear envelope was also stained. The possible meaning of the NADPH diaphorase activity in the Leydig cells of mice was discussed.

Animals↗
PubMed1998

Meningitis caused by a serogroup W135 clone of the ET-37 complex of Neisseria meningitidis in West Africa.

Meningococci belonging to serogroup W135 caused several cases of meningococcal meningitis in The Gambia in 1995 and were isolated during a serogroup A epidemic in Mali in 1994. The eight isolates tested belonged to the same clone of the ET-37 complex and differed in several bands from the pulsed-field gel electrophoresis restriction pattern of serogroup C meningococci of the ET-37 complex isolated in Mali. Three of 6 patients infected in The Gambia died, indicating that this W135 clone is virulent. Vaccines that protect only against infections with meningococci belonging to serogroups A and C are usually used to control outbreaks in Africa, although vaccines containing the W135 polysaccharide are available. The findings of this study indicate that outbreaks of meningococcal meningitis in Africa can be associated with serogroup W135 infections and that serogrouping is essential before vaccination campaigns are started.

Adolescent↗
PubMed1998

Sequence diversity, predicted two-dimensional protein structure, and epitope mapping of neisserial Opa proteins.

The sequence diversity of 45 Opa outer membrane proteins from Neisseria meningitidis, Neisseria gonorrhoeae, Neisseria sicca, and Neisseria flava indicates that horizontal genetic exchange of opa alleles has been rare between these species. A two-dimensional structural model containing four surface-exposed loops was constructed based on rules derived from porin crystal structure and on conservation of sequence homology within transmembrane beta-strands. The minimal continuous epitopes recognized by 23 monoclonal antibodies were mapped to loops 2 and 3. Some of these epitopes are localized on the bacterial cell surface, in support of the model.

Amino Acid Sequence↗
PubMed1998

Necessity of molecular techniques to distinguish between Neisseria meningitidis strains isolated from patients with meningococcal disease and from their healthy contacts.

Serogroup C strains of Neisseria meningitidis were isolated from a Germany patient with severe meningococcal disease after a trip to the Czech Republic. These strains (case isolates) were characterized by classical and molecular techniques, as were other strains (carrier isolates) isolated from healthy contacts. Five of 10 carrier isolates had switched off the expression of capsular polysaccharide, as demonstrated by a serogroup-specific PCR. The two case isolates were indistinguishable by multilocus sequence typing and belonged to the ET-37 complex. The carrier isolates belonged to four different sequence types, all unrelated to that of the case strains. Pulsed-field gel electrophoresis showed that the case isolates differed from reference ET-37 complex strains from the Czech Republic and Canada as well as from all the carrier isolates. The isolate from the patient's nasopharynx was indistinguishable from the blood isolate except for a 40,000-bp chromosomal deletion that had occurred during systemic spread.

Adolescent↗
PubMed1998

Bladder involvement in systemic sclerosis: urodynamic and histological evaluation in 23 patients.

Lower tract involvement of systemic sclerosis is an uncommon manifestation. In this study we have evaluated the functional and morphologic vesical changes in 23 female patients with systemic sclerosis to investigate if bladder dysfunction was correlated with an extended skin sclerosis and/or a more serious organ involvement. Urodynamic alterations were observed in only 3 cases. Urinary symptoms and urodynamic features were correlated neither with severity of vesical fibrosis nor with visceral involvement. Autonomic dysfunction was detected in 13 patients.

Adult↗
PubMed1998

Functional evaluation of different ileal neobladders and ureteral reimplantation techniques.

OBJECTIVES: To compare and assess the function of ileal neobladders with different reconfiguration and with several types of ureteral reimplantation. METHODS: Forty-five male patients underwent radical cystectomy and detubularized ileal neobladder. In 20 patients an ileal neobladder was carried out according to Studer's technique, in 12 a 'W'- and in 13 a 'U'-shaped neobladder. In the Studer's patients 60 cm of ileum was used, in the 'W' 40 and in the 'U' 30 cm. For the uretero-ileal anastomosis Nesbit's technique was utilized in the Studer's, in the 'W' and 'U' neobladders Camey Le Duc's technique was performed instead. Four patients underwent a serous-lined extramural tunnel reimplantation. Follow-up included a functional and morphological study of the urinary system and a urodynamic study. RESULTS: All Nesbit's uretero-ileum anastomoses resulted refluent when the reservoir was filled up, 15 of 50 ureteral reimplantations according to the Camey Le Duc technique showed reflux at full filling. At 3, 6 and 12 months follow-up, the double reconfiguration reservoirs (Studer's and 'W') showed a larger capacity and a lower maximum pressure than neobladders with a single bending. At 12 months, continence and the voiding interval time was significantly higher in the double reconfiguration than in the 'U' neobladders. CONCLUSION: The double reconfiguration of the reservoir ('W') might be preferable to that with a single one. As for the type of ureteral anastomosis to select, the problem is still debatable even if in our case-control study we have had better results in terms of reflux and stenosis with the uretero-enteric anastomosis with Nesbit's and associated afferent long tubular ileal limb than with Studer's technique.

Aged↗
PubMed1997

DNA-binding specificity of the homeodomain-leucine zipper domain.

Homeodomain-leucine zipper (HD-Zip) proteins are putative transcription factors identified only in plants. The study of the DNA-binding properties of the ATHB-1 and -2 HD-Zip (HD-Zip-1 and -2) domains showed that they interact with DNA as homodimers and recognize two distinct 9 bp pseudopalindromic sequences, CAAT(A/T)ATTG (BS-1) and CAAT(G/C)ATTG (BS-2), respectively, as determined by selecting high-affinity binding sites from random-sequence DNA. Here, we report a mutational analysis of the HD-Zip-2 domain. We determined that conserved amino acid residues of helix 3, Val47 and Asn51, and Arg55 are essential for the DNA-binding activity of the HD-Zip-2 domain. We demonstrated that the preferential recognition of a G/C base-pair at the central position by the HD-Zip-2 domain is abolished either by the replacement of Arg55 with lysine or by the substitution of Glu46 and Thr56 with the corresponding residues of the HD-Zip-1 domain (alanine and tryptophan, respectively). In contrast, substitution of Arg55 with lysine in the HD-Zip-1 domain significantly reduced DNA-binding activity without changing the specificity of recognition. Finally, we determined that differences in residues outside helix 3 further contribute to the DNA-binding specificity of the HD-Zip domain. Taken together, the data strongly suggest that the preferential recognition of BS-2 and -1 by the HD-Zip-2 and -1 domains, respectively, may be attributable to a distinct orientation of the side-chain of Arg55 in these two domains.

Amino Acid Sequence↗
PubMed1997

Polylysine induces changes in membrane electrical properties of K562 cells.

The ionic environment of the cell membrane is of extreme importance in maintaining cell integrity and the numerous functions necessary for cell growth, differentiation, etc., as well as in cell-biomaterial interactions. In this study, the effects of polylysine (a basic poly-amino acid with a net positive charge which is often used to coat biomaterials surfaces) on the erythroleukemic K562 cell membrane were investigated. In particular, the effects of this polycation were evaluated using dielectric relaxation studies in the radiofrequency range with which it is possible to measure both active ionic transport across the cell membrane (membrane conductivity) and the static charge distribution present on the cell surface due to the structural components of the cell membrane (membrane permittivity). The conductivity of the cytosol can also be determined. The results demonstrate that while the conductivity of the cytosol is not significantly altered, both the conductivity and permittivity of the K562 cell membrane are varied by exposure of these cells to polylysine. These observations indicate that both active ionic transport and the type, quantity, or distribution of membrane components such as lipids, proteins, and polysaccharides may also be altered. Although the precise mechanisms by which these variations in K562 cells occur are unknown, it can be hypothesized that changes in the growth characteristics of these cells may be in part responsible. In particular, as demonstrated by light microscopic examination of K562 cells directly in the culture flasks, the cells in polylysine-coated flasks do not grow in suspension as do the controls, but rather show anchorage-dependent-like behavior. It is this important change from suspension to monolayer growth induced by polylysine that may be responsible for the changes in membrane electrical parameters.

Cell Division↗
PubMed1997

Clonal descent and microevolution of Neisseria meningitidis during 30 years of epidemic spread.

Serogroup A meningococci of subgroups III, IV-1 and IV-2 are probably descended from a common ancestor that existed in the nineteenth century. The 10.5kb sequences spanning five distinct chromosomal loci, encoding cell-surface antigens, a secreted protease or housekeeping genes and intergenic regions, were almost identical in strains of those subgroups isolated in 1966, 1966 and 1917 respectively. During the subsequent two to three decades, all of these loci varied as a result of mutation, translocation or import of DNA from unrelated neisseriae. Thus, microevolution occurs frequently in naturally transformable bacteria. Many variants were isolated only once or within a single geographical location and disappeared thereafter. Other variants achieved genetic fixation within months or a few years. The speed with which sequence variation is either eliminated or fixed may reflect sequential bottlenecks associated with epidemic spread and contrasts with the results of phylogenetic analyses from bacteria that do not cause epidemics.

Alleles↗
PubMed1997

[Malaria: state of art].

Some actual aspects of malaria are here described. After an outline of the actual epidemiological situation of malaria endemic in the world and some historical reports on Italian malaria phenomena before the institution of malaria control measures, chemoprophylaxis and its more problematic aspects, mainly related to multiresistant drug Plasmodium falciparum strains, are discussed in the first part. In the second part the factors potentially implicated in a reintroduction of malaria in free areas are analyzed; with a special reference to climatic changes. Finally the more recent vaccine perspectives are summarized; the authors discuss the principal experiences made using synthetic peptides of different plasmodial origin.

English Abstract↗
PubMed1997

Use of new nephrostomy catheter for treatment of renal neonatal candidiasis.

Systemic candidiasis with renal involvement is a rare but well-recognized complication during neonatal intensive care treatment. In addition to intravenous administration of amphotericin B, decompression of the renal pelvis and irrigation of the involved kidney with the same drug through a nephrostomy tube will provide a high concentration of antifungal agent with a flushing effect. This procedure is not always possible due to the small size of the neonatal kidneys. We have conceived a new percutaneous trocar nephrostomy which allows its application directly in an incubator without using X-rays during a single procedure. In 3 cases a bilateral percutaneous nephrostomy was performed directly in the incubator using a one-step ultrasonically guided maneuver under local anesthesia. The funguria was successfully eradicated in all cases. The availability of a nephrostomy trocar of small dimensions leads us to an improved renal approach in newborns.

Amphotericin B↗
PubMed1997

[Urotheliomas of the upper urinary tract. The role of computed tomography in integrated diagnostic imaging].

INTRODUCTION: Transitional cell carcinomas are frequent in the bladder but rare in the renal pelvis. Most upper urinary tract cancers are suspected and detected with urography and retrograde pyelography; CT is important in the questionable cases at US, urography and retrograde pyelography, but it is also useful to detect locoregional disease. We report the findings of 35 patients, with ureteral lesions to assess the role of CT in the diagnosis and staging. MATERIALS AND METHODS: Thirty-five patients were examined with US and CT; 27 underwent urography, 16 retrograde pyelography and 4 nephrostomic pyelography, CT staging was made with Hahn's criteria related to TNM (stages CT I, CT II, CT III). All patients underwent surgery and the histologic findings were compared with CT staging. RESULTS: CT detected all lesions and characterized them from a morphological viewpoint (intraluminal minus, wall thickening). Using Hahn's CT staging we obtained agreement with histologic findings in 21 of 23 cases in CT stage I, six of 10 in CT stage II and 4 of 5 in CT stage III. CONCLUSIONS: CT is an important tool for both diagnosis and therapy because it shows the renal cavities and parenchyma and permits accurate staging, differentiating the tumors localized in the wall from those with local spread or distant metastases. In our experience, CT is not useful to differentiate mucosal from pelvic-ureteral muscle invasion but peripelvic and periureteral fat invasion can be suspected when the infiltrated wall exhibits an irregular and spiculated profile.

Adult↗
PubMed1996

Twilight-zone and canopy shade induction of the Athb-2 homeobox gene in green plants.

We present evidence that a novel phytochrome (other than phytochromes A and B, PHYA and PHYB) operative in green plants regulates the "twilight-inducible" expression of a plant homeobox gene (Athb-2). Light regulation of the Athb-2 gene is unique in that it is not induced by red (R)-rich daylight or by the light-dark transition but is instead induced by changes in the ratio of R to far-red (FR) light. These changes, which normally occur at dawn and dusk (end-of-day FR), also occur during the daytime under the canopy (shade avoidance). By using pure light sources and phyA/phyB null mutants, we demonstrated that the induction of Athb-2 by changes in the R/FR ratio is mediated for the most part by a novel phytochrome operative in green plants. Furthermore, PHYB plays a negative role in repressing the accumulation of Athb-2 mRNA in the dark and a minor role in the FR response. The strict correlation of Athb-2 expression with FR-induced growth phenomena suggests a role for the Athb-2 gene in mediating cell elongation. This interpretation is supported by the finding that the Athb-2 gene is expressed at high levels in rapidly elongating etiolated seedlings. Furthermore, as either R or FR light inhibits cell elongation in etiolated tissues, they also down-regulate the expression of Athb-2 mRNA. Thus, these data support the notion that changes in light quality perceived by a novel phytochrome regulate plant development through the action of the Athb-2 homeobox gene.

Journal Article↗
PubMed1996

The isoprenoid pathway: cloning and characterization of fungal FPPS genes.

Farnesylpyrophosphate synthase (FPPS) is a key enzyme in isoprenoid biosynthesis. Several classes of essential metabolites, including sterols, quinones, carotenoids and gibberellins, are terpenoids with high biological activity. The structural gene for FPP synthase was isolated from two ascomycete fungi, Neurospora crassa and Gibberella fujikuroi. A comparative analysis of the nucleotide sequences of both FPPS genes revealed the presence of introns at the same positions at the 5' end of the coding regions. Furthermore, the most conserved region of the gene was isolated from two other plant pathogenic fungi, Sphaceloma manihoticola and Claviceps purpurea, by PCR. Sequence analysis showed a high degree of similarity between the deduced proteins of all known FPP synthase genes. In contrast to animals, all analyzed fungi contain a single copy of the gene, although FPP is the precursor for essential sterol and quinone biosynthesis and secondary metabolites, such as gibberellins, as well. Transcription analysis in different light regimes has shown that the FPPS genes in G. fujikuroi and N. crassa are not regulated by light induction.

Alkyl and Aryl Transferases↗
PubMed1996

The oxidizing agent menadione induces an increase in the intracellular molecular oxygen concentration in K562 and A431 cells: direct measurement using the new paramagnetic EPR probe fusinite.

The intracellular molecular oxygen concentration in control and menadione-treated K562 (an erythroleukemic cell line that grows in suspension) and A431 (an epidermal carcinoma that grows in monolayer) cells was measured directly by using the new electron paramagnetic resonance (EPR) probe fusinite. Because the oxidizing agent menadione is known to damage mitochondria and the cytoplasmic membrane in other cell systems, before conducting measurements of oxygen concentration in K562 and A431 cells, it was necessary to establish injury in these systems as well. Consequently, morphological and flow cytometric analyses were conducted after menadione treatment. The data presented here show that the two cell lines are heavily damaged by menadione. Once this menadione-induced injury was demonstrated, measurements of oxygen concentration were carried out in both K562 and A431 cells. Treatment with this quinone induces a sharp increase in intracytoplasmic molecular oxygen in both cell lines (from about 1% to about 10 and 15% in K562 and A431 cells, respectively). In addition, to gain a more complete understanding of the effects of menadione on cells, the extracellular molecular oxygen concentration and the oxygen consumption rate were also measured in control and menadione-treated K562 cells. These measurements demonstrate that menadione treatment results in an increase in the extracellular oxygen concentration (from about 5% in controls to 15% in treated cells) as well as a decrease in the oxygen consumption rate (from about 10 ng O/min/10(6) cells in controls to 3 ng O/min/10(6) cells after menadione exposure). The importance of the new EPR probe fusinite in monitoring directly cellular functions in which oxygen is involved and the effects of menadione on cellular oxygen balance are discussed.

Calibration↗
PubMed1996

Bladder instability and incontinence after radical prostatectomy.

Thirty-nine patients were evaluated after retropubic prostatectomy, by urodynamic studies. They were divided into three groups depending upon the degree of urinary continence. A statistically significant difference was found between different groups in mean functional profile length and maximal urethral closure pressure. Differences in age, previous prostatic surgery, tumour extension, or preservation of the neurobundles did not have any significant influence on recovery of continence.

Aged↗