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Biomedical subjects

S Romani

Publications and source records attributed to S Romani.

At least 19 recordsLinked to original sources
PubMed2006

[Homozygous antithrombin type HBS deficiency; a family study].

Congenital antithrombin (AT) deficiency is the most thrombotic genetic abnormality of haemostasis. Total quantitative deficits are lethal as early as life intra-uterine. Only homozygous mutations concerning the heparin-binding site are compatible with life. We report here the case of an 18 years old patient with recurrent deep venous thrombosis of the inferior members. Haemostasis exploration shows a decreased AT activity (11%) in the presence of heparin while AT progressive activity and AT antigen are normal. Two other homozygous sisters are identified in this family study. Molecular study of AT gene show Arg47-Cys substitution, already reported in the literature with patients of different geographic origins. Treatment of patients with homozygous AT type HBS deficiency is similar that for patients with heterozygous AT deficiency; a continuous prophylactic anticoagulant treatment is always necessary and AT concentrates infusions are required in all situations needing curative heparin treatment.

Adolescent↗
PubMed2001

Analysis of urinary N-acetyl-S-(N-methylcarbamoyl)cysteine, the mercapturic acid derived from N,N-dimethylformamide.

Human biotransformation of the industrial solvent N,N-dimethylformamide gives raise to N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) which has the longest half-life (about 23 h) among urinary metabolites of N,N-dimethylformamide. It could be used for monitoring industrial exposure over several workdays, by measuring it in urine samples collected at the end of the working week. This is consistent with the suggestions of the American Conference of Governmental Industrial Hygienists, which established a limit of 40 mg/l for the year 2000. An easy, cheap and user-friendly method has been developed for determination of urinary AMCC. Unlike currently available methods, it requires neither a time-consuming preparation phase nor gas chromatographic analysis with a nitrogen-phosphorus or mass detector. The method uses high-performance liquid chromatography (HPLC), with an UV detector at 436 nm. A 10-microl volume of urine is added to a carbonate-hydrogen carbonate buffer and mixed with a dabsyl chloride solution in acetonitrile. The reaction between AMCC and the reagent is performed at 70 degrees C for 10 min. The 'dabsylated' product is stable for at least 12 h. After brief centrifugation, the solution is ready for HPLC analysis using a C18 column (250 x 4.6 mm, 5 microm). The method is sensitive (detection limit 1.8 mg/l) and specific. It identified urinary AMCC in urine of 40 subjects not exposed to N,N-dimethylformamide with a median concentration of 3.9 mg/l. In urine samples from 20 workers exposed to N,N-dimethylformamide (5-40.8 mg/m3), AMCC concentrations ranged from 16 to 170 mg/l. Industrial toxicology laboratories with limited instrumentation will be able to use it in the biological monitoring of workers exposed to N,N-dimethylformamide.

Acetylcysteine↗
PubMed2000

The EGF and FGF receptors mediate neuroglian function to control growth cone decisions during sensory axon guidance in Drosophila.

Cell adhesion molecules (CAMs) implement the process of axon guidance by promoting specific selection and attachment to substrates. We show that, in Drosophila, loss-of-function conditions of either the Neuroglian CAM, the FGF receptor coded by the gene heartless, or the EGF receptor coded by DER display a similar phenotype of abnormal substrate selection and axon guidance by peripheral sensory neurons. Moreover, neuroglian loss-of-function phenotype can be suppressed by the expression of gain-of-function conditions of heartless or DER. The results are consistent with a scenario where the activity of these receptor tyrosine kinases is controlled by Neuroglian at choice points where sensory axons select between alternative substrates for extension.

Animals↗
PubMed2000

Autoxidation of packed almonds as affected by maillard reaction volatile compounds derived from roasting.

Shelled almonds of two Italian varieties, Romana and Pizzuta, peeled and unpeeled, were roasted and packed under different conditions: air (control), vacuum, and Maillard reaction volatile compounds (MRVc) derived from the roasting process. Samples were stored for approximately 8 months at room temperature, without light, and, at regular intervals, were collected and analyzed to evaluate the progress of lipid oxidation. Peroxide values, triglyceride oligopolymers, and oxidized triglycerides were evaluated during the storage time. Results showed that, although the MRVc atmosphere did not protect the lipid fraction of almonds as well as the vacuum condition; nevertheless, it was more protective than the control atmosphere, showing an antioxidant effect. The effect of the natural coating was a strong protection against lipid oxidation; in fact, only the unpeeled samples showed peroxide values lower than the threshold of acceptability (25 milliequiv of O(2)/kg of oil). Moreover, at the end of the storage period, Pizzuta almonds showed a greater deterioration than those of the Romana variety.

Cooking↗
PubMed2000

Screening on the occurrence of ochratoxin A in green coffee beans of different origins and types.

Since to our knowledge no data are available in the literature regarding the influence of green coffee type and origin on ochratoxin A (OTA) content, determinations were carried out in order to assess the level of OTA contamination in green coffee samples of different provenience. A total of 162 samples of green coffee beans from various countries (84 from Africa, 60 from America, and 18 from Asia) were analyzed for OTA. Both the amount and the variability of OTA levels were tested as a function of green coffee provenience. The results showed that 106 of the overall samples were positive for OTA, with concentration ranging from 0 to 48 microg/kg (ppb). In particular, it was possible to verify that African samples were more contaminated with respect to samples of other origin in terms of frequency and level of OTA; the highest concentrations observed were 18 and 48 microg/kg in two samples from The Congo.

Coffee↗
PubMed1997

Specific muscle identities are regulated by Krüppel during Drosophila embryogenesis.

During Drosophila embryogenesis, mesodermal cells are recruited to form a complex pattern of larval muscles. The formation of the pattern is initiated by the segregation of a special class of founder myoblasts. Single founders fuse with neighbouring nonfounder myoblasts to form the precursors of individual muscles. Founders and the muscles that they give rise to have specific patterns of gene expression and it has been suggested that it is the expression of these founder cell genes that determines individual muscle attributes such as size, shape, insertion sites and innervation. We find that the segmentation gene Krüppel is expressed in a subset of founders and muscles, regulates specific patterns of gene expression in these cells and is required for the acquisition of proper muscle identity. We show that gain and loss of Krüppel expression in sibling founder cells is sufficient to switch these cells, and the muscles that they give rise to, between alternative cell fates.

Animals↗
PubMed1996

Krüppel, a Drosophila segmentation gene, participates in the specification of neurons and glial cells.

We report that the Drosophila segmentation gene Krüppel (Kr) is expressed in neural precursor cells, neurons and glial cells at different stages of neurogenesis and that Kr mutants develop aberrant peripheral (PNS) and central (CNS) nervous systems. Expression derived from a Kr minigene rescues the segmentation defects but these embryos continue to lack most of the neural Kr activity. Phenotypic analysis of the rescued embryos indicates that, in addition to overall effects on the PNS and CNS structure via its segmentation role, Kr expression in the nervous system is functionally required for establishing particular neural and glial fates.

Animals↗
PubMed1993

Molecular characterization of the lethal of scute genetic function.

The lethal of scute (l'sc) genetic function, which plays an essential role in the early development of the central nervous system of the Drosophila embryo, is localized within the achaete-scute complex (AS-C). Several lines of evidence have suggested that the AS-C T3 transcription unit corresponds to the l'sc function. We demonstrate that short fragments of DNA, containing the T3 transcribed region and a few kilobases of flanking sequences, rescue, albeit partially, the lethality and neural phenotype of l'sc deletions. Still, the complex wild-type pattern of expression of T3 is not reproduced by the transduced genes. This depends on cis-control elements scattered within the entire AS-C DNA and intermingled with regulatory elements specific for other AS-C transcription units. These elements are necessary for the initial activation of T3 in the neuroectoderm, probably mediated by axis-patterning genes. The presence of a cluster of E-boxes, upstream of the T3 transcribed region, suggests another level of control of T3 expression by basic-helix-loop-helix proteins, among them its own gene product.

Amino Acid Sequence↗
PubMed1991

[Measurement of gastric emptying with Tc 99m. Technique and reliability of the test].

Among the various methods used to measure gastric emptying time, scintigraphy is nowadays the technique of choice. Since only few data are available on the operative characteristics of the method, the authors investigated reproducibility, sensitivity, and specificity of a modified scintigraphic technique for the measurement of gastric emptying time. Three groups of subjects--healthy volunteers, patients with functional dyspepsia, and patients with upper gastrointestinal conditions--were administered liquid meals having various standard consistencies (349 tests on the whole). In both healthy volunteers and dyspeptic patients the method had high sensitivity (72%), good specificity (69%), and low intra-subject variation (25%). In all cases, the increase in meal density produced a delay in gastric emptying. Dyspeptic patients had slow gastric emptying of high-fiber meals, while in duodenal ulcer and in atrophic gastritis emptying was significantly faster. The radionuclide method proved valuable in measuring gastric emptying and was useful to confirm the pathogenesis of the various conditions. As for functional and organic pathologic conditions, it allowed treatment efficacy to be evaluated.

Adult↗
PubMed1989

Molecular analysis of the asense gene, a member of the achaete-scute complex of Drosophila melanogaster, and its novel role in optic lobe development.

The achaete-scute complex (AS-C) comprises five genetic regions: achaete, scute (sc) alpha, lethal of sc, sc beta and sc gamma. Each region promotes the determination and positional specification of different, but partially overlapping, subsets of neural elements of Drosophila. In this work, we report a molecular characterization of the sc gamma region. It comprises 22 kb of DNA and contains two transcription units, only one of which, named asense (ase), seems involved in neurogenesis. ase encodes a protein that shares with other three AS-C proteins a domain containing a helix--loop--helix motif characteristic of a group of DNA-binding proteins. In the embryo, ase is expressed in neural precursor cells, a pattern consistent with the known requirement of sc gamma for the development of the larval nervous system. In late third-instar larvae, the gene is expressed in developing structures of the central nervous system (CNS), namely the anlagen of the optic lobes and in many cells, including neuroblasts, of the central brain and ventral ganglia. Its removal leads to anatomical defects in the adult optic lobes. This is the first demonstration of a role for the AS-C in the development of the adult CNS.

Amino Acid Sequence↗
PubMed1989

Expression of achaete and scute genes in Drosophila imaginal discs and their function in sensory organ development.

Several kinds of sensory organs (SOs) appear in stereotyped positions on the adult Drosophila cuticle. The generation of these SOs requires the activity of the achaete (ac) and scute (sc) genes. To investigate whether ac and sc also provide spatial information for the positioning of SOs, we have analyzed the patterns of expression of these genes in the wing imaginal disc around the time that SO precursors are being specified. We find that expression coincides with and is restricted to areas of the disc where these precursors are known to be located. In the loss-of-function sc mutant, sc RNA is depleted in a single area located in the region where the precursor for the suppressed macrochaeta should be found. Moreover, some, and probably all, SOs require expression of these genes to reach the earliest detectable differentiated state. These and other results presented here, together with the finding that expansion of the areas of ac and/or sc expression causes the development of ectopic SOs, indicate that ac and sc promote the determination of SO precursors and delimit the regions of the imaginal discs where they can develop.

Animals↗
PubMed1987

The achaete-scute complex is expressed in neurogenic regions of Drosophila embryos.

The achaete-scute gene complex (AS-C) of Drosophila melanogaster is involved in the development of the embryonic central nervous system and the cuticular sensory organs of both larva and adult. We have determined the embryonic spatial distributions of three transcripts encoded in the achaete, scute alpha and lethal of scute regions of the complex. The RNAs are present mainly between the blastoderm/early gastrula and the stage of germ band shortening. The patterns of expression are complex and evolve rapidly, affecting most or all of the known neurogenic regions. Gene expression precedes and is concomitant with the histological appearance of precursors of neural cells. These results support a role for the AS-C in determination and early differentiation of embryonic neural cells.

Journal Article↗
PubMed1987

Synthesis of the trypsin fragment 10-25/75-88 of mouse nerve growth factor. I. The protected tetradecapeptide 75-88.

Cyanogen bromide cleavage followed by trypsin digestion of mouse nerve growth factor (NGF) allowed the isolation of a double chain unsymmetrical cystine peptide of high neurotrophic activity. The presence of tryptophan residues severely limits the synthetic approaches for selective disulfide bridging. The strategy applied for such a purpose as well as the preparation of the suitably protected tetradecapeptide corresponding to sequence 75-88 as key intermediate for the synthesis of the NGF fragment 10-25/75-88 are described.

Amino Acid Sequence↗
PubMed1982

Evaluation of post-pneumonectomy space by computed tomography.

Twenty-two patients who had undergone pneumonectomy for various reasons were evaluated by computed tomography (CT) in order to study the post-pneumonectomy space (PPS). In 13 of 22 cases, the residual PPS contained fluid, even years following surgery. In 9 of 22 cases, the PPS was obliterated. Obliteration of the PPS, one of the events that may follow pneumonectomy, is significantly correlated with the expansion of the nonoperated lung (coefficient, 0.84). Obliteration of the PPS does not present a significant coefficient of correlation with the following parameters, also considered in this study: time interval between surgery and CT, presurgical tests of respiratory function, hemidiaphragm elevation, and retraction of operated hemithorax. The fluid contained in the PPS does not organize but persists or is reabsorbed. Mediastinal shift depends on the expansion of the residual lung. The mediastinum rotates following right pneumonectomy and shifts following left pneumonectomy. The usefulness of CT in the follow-up of the pneumonectomized patient is stressed.

Adult↗
PubMed1982

1-(tert-butylthio)-1,2-hydrazinedicarboxylic acid derivatives. New reagents for the introduction of the S-tert-butylthio group into cysteine and cysteine derivatives.

The sterically hindered tert-butyl thiol reacts smoothly with azodicarboxylic acid derivatives only upon addition of catalytic amounts of sodium alcoholate, yielding crystalline and analytically well characterized 1-(tert-butylthio)-1,2-hydrazinedicarboxylic acid derivatives. These sulfur-activated reagents were found to be stable on storage and well suited as tert-butylthio carriers for the introduction of this thiol-protecting group on cysteine, cysteine derivatives and cysteine peptides; the related compounds are obtained in high yields.

Cysteine↗
PubMed1982

A new method for the selective synthesis of unsymmetrical cystine peptides.

A convenient method for the synthesis of unsymmetrical cystine peptides is described, which is based on the conversion of one cysteine component to the corresponding sulfenohydrazide by reaction with azodicarboxylic acid derivatives. Following the isolation and characterization of this S-activated intermediate, its thiolysis via the second cysteine component leads to the desired disulfide bridging.

Cysteine↗