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Biomedical subjects

M Signore

Publications and source records attributed to M Signore.

At least 19 recordsLinked to original sources

Plasma levels of IL-10 and nitric oxide under two different anaesthesia regimens.

BACKGROUND AND OBJECTIVE: An alteration in production of both interleukin-10 (IL-10) and nitric oxide (NO) has been found following surgical/anaesthesia trauma. It is also suggested that IL-10 could be an important factor in regulating NO metabolism during the postoperative period. Furthermore, NO seems to play a crucial role in the anaesthetic state. The purpose of this study was to investigate plasma levels of IL-10 and NO following surgery, any possible correlation between these two variables and whether anaesthesia technique could influence NO and IL-10 circulating concentrations. METHODS: Thirty-two patients scheduled to undergo elective major surgery were enrolled in the study and allocated into two groups to receive two different techniques of anaesthesia, total intravenous (i.v.) anaesthesia (Group I) and inhalational anaesthesia (Group II). Blood samples were drawn before (t0), at the end (t1) of operation and after 24 h (t2). Plasma IL-10 and NO levels were measured by using an enzyme-linked-immunosorbent assay (ELISA) and a total NO assay kit, respectively. RESULTS: In both patient groups there was a significant decrease of plasma NO levels at the end of surgery (30.35 +/- 2.70 mmol L(-1) at t0 to 13.76 +/- 1.51 mmol L(-1) at t1 in Group I, P < 0.0001; 28.23 +/- 2.50 mmol L(-1) at t0 to 11.38 +/- 0.95 mmol L(-1) at t1 in Group II, P < 0.0001). This reduction remained at 24 h postoperatively (14.33 +/- 1.52 mmol L(-1) in Group I, P < 0.0001; 12.52 +/- 1.11 mmol L(-1) in Group II, P < 0.0001, both vs. t0). There was an increase in IL-10 concentrations (26.35 +/- 3.42 pg mL(-1) and 75.39 +/- 8.33 pg mL(-1) at t1 and t2, respectively, vs. 4.93 +/- 0.31 pg mL(-1) at t0, P = 0.03 and P < 0.0001, respectively, in Group I; 26.18 +/- 3.22 pg mL(-1) and 69.91 +/- 7.33 pg mL(-1) at t1 and t2, respectively, vs. 5.50 +/- 0.33 pg mL(-1) at t0, P = 0.02 and P < 0.0001, respectively, in Group II). No relationship was found between circulating IL-10 and NO. CONCLUSIONS: During the postoperative period, IL-10 overproduction does not correlate with the decrease in systemic NO concentration.

Adolescent↗

Chromosome instability in T-cells cultured in the presence of pancuronium or fentanyl.

BACKGROUND: Genomic instability is recognized as a cause of cellular apoptosis and certain drugs that exhibit a proapoptotic effect are also able to induce chromosome damage. Since we found in recent experiments that drugs such as pancuronium and fentanyl exerted an apoptogenic effect on T cells, we studied the capacity of those agents to promote chromosome instability, i.e. chromosome aberrations (CA) and telomeric associations (tas) in peripheral blood lymphocytes. METHODS: Lymphocytes from healthy donors were cultured with pancuronium or fentanyl, using two different concentrations for each drug: 20 and 200 ng/ml for pancuronium and 10 and 30 ng/ml for fentanyl, respectively. Cells were exposed to each concentration of these drugs either for 24 or 48 h. The higher concentration chosen was the same at which we detected the proapoptotic effect in our previous works. Cytogenetic analysis was performed by means of a standard technique and chromosome aberrations or telomeric associations were blindly evaluated by two independent observers. RESULTS: The chromosome aberrations we observed in treated cells were not significantly different from control lymphocytes. However, an unusual rate of telomeric associations (P < 0.001) was detected in cells exposed to both pancuronium and fentanyl, at each concentration tested and at each exposure time of the study. CONCLUSIONS: Fentanyl and pancuronium do not have a direct clastogenic effect on T cultures, but at the same concentrations at which we demonstrated their apoptogenic power, these drugs are able to increase genomic instability through inducing an elevated rate of telomeric associations. Such a capacity could exploit in peripheral T cells the same mitochondrion-mediated signal pathway of apoptosis death.

Adult↗

Pancuronium bromide, a non-depolarizing muscle relaxant which promotes apoptosis of blood lymphocytes in vitro.

BACKGROUND: Several compounds used in anesthesia practice have demonstrated to impair immune function and to influence the process of apoptotic death in T cell population following surgical trauma. We designed this study to test in vitro the impact of neuromuscular blocker, such as pancuronium, at clinically relevant concentration on lymphocyte apoptosis, death factor expression and mitochondrial function. METHODS: Following isolation, lymphocytes were incubated with pancuronium bromide at a clinically relevant concentration (0.136 micro mol l-1) for 3 h at 37 C in a 5% carbon-dioxide-humidified atmosphere and the frequency of apoptotic lymphocytes was then measured. We also investigated crucial steps in the apoptotic process, including Fas/Fas ligand (FasL) phenotype, intracellular expression of the interleukin-1beta-converting enzyme (ICE) p20, mitochondrial membrane potential (DeltaPsim), generation of mitochondrial reactive oxygen species, and glutathione (GSH) levels. Control experiments were performed incubating cells in the complete culture medium added with the dilution medium of the drug without addition of the drug. RESULTS: Expression of Fas, FasL and ICEp20 was six-fold, four-fold, and five-fold increased, respectively, among pancuronium-treated lymphocytes with respect to control cultures (P = 0.0001). The percentage of cells exhibiting either dissipation of mitochondrial membrane potential or increased production of reactive oxygen species was seven-fold increased following exposure to pancuronium compared with untreated lymphocytes (P = 0.0001). These findings were associated with a decrease in GSH level. In addition, the frequency of apoptotic cells was 10-fold greater among lymphocytes cultured in the presence of the drug with respect to control cultures. (P = 0.0001). CONCLUSION: Our data suggest an apoptogenic effect of pancuronium in vitro at clinically relevant concentration on peripheral blood lymphocytes. This could be implicated in the transient immune suppression following a surgical operation.

Adult↗

Abnormal "low grade" transformation zone: current diagnostic gold standard.

The aim of this work was to examine different methods of investigation in the diagnosis of the abnormal "low grade" transformation zone of the portio. Over a period of one year 41 patients subjected to colposcopic examination underwent exo-endocervical sampling for oncologic evaluation and for detection of viral and bacterial infections (HPV, HSV, adenovirus, mycoplasmas and chlamydia trachomatis), as well as portio biopsy. A 65.8% correlation was found between cytology and the HPV-DNA test results, while histology and the presence of the HPV virus agreed in 51.4% of cases. In those cases in which minimal histological alterations were found (koilocytosis) a high percentage of HPV negativity was found. In discordant negative cytologic tests that were however positive for HPV by PCR, the genotypes identified were always 6 and 11.

Base Sequence↗

Otx1 null mutant mice show partial segregation of sensory epithelia comparable to lamprey ears.

We investigated the development of inner ear innervation in Otx1 null mutants, which lack a horizontal canal, between embryonic day 12 (E12) and postnatal day 7 (P7) with DiI and immunostaining for acetylated tubulin. Comparable to control animals, horizontal crista-like fibers were found to cross over the utricle in Otx1 null mice. In mutants these fibers extend toward an area near the endolymphatic duct, not to a horizontal crista. Most Otx1 null mutants had a small patch of sensory hair cells at this position. Measurement of the area of the utricular macula suggested it to be enlarged in Otx1 null mutants. We suggest that parts of the horizontal canal crista remain incorporated in the utricular sensory epithelium in Otx1 null mutants. Other parts of the horizontal crista appear to be variably segregated to form the isolated patch of hair cells identifiable by the unique fiber trajectory as representing the horizontal canal crista. Comparison with lamprey ear innervation reveals similarities in the pattern of innervation with the dorsal macula, a sensory patch of unknown function. SEM data confirm that all foramina are less constricted in Otx1 null mutants. We propose that Otx1 is not directly involved in sensory hair cell formation of the horizontal canal but affects the segregation of the horizontal canal crista from the utricle. It also affects constriction of the two main foramina in the ear, but not their initial formation. Otx1 is thus causally related to horizontal canal morphogenesis as well as morphogenesis of these foramina.

Animals↗

Experience with a questionnaire administered by emergency medical service for pre-hospital identification of patients with acute stroke.

We prospectively verified whether an ad-hoc questionnaire administered by phone supports pre-hospital suspicion of stroke in order to reduce the time before care is given. From June 1996 to May 1997, physicians of the Emergency Medical Service in the area of Bergamo, Italy asked all people calling for a patient with symptoms and signs suggesting a cerebral vascular injury to immediately answer some questions on common symptoms and signs of stroke. The medical records of the patients hospitalized at Ospedali Riuniti of Bergamo were reviewed at the end of the study by a single neurologist, skilled in stroke management and blinded to the questionnaires. Sensitivity and specificity, in addition to positive and negative predictive values, of single questions versus final diagnosis were assessed. Logistic regression analysis was also performed to identify those questions useful to suspect strokes. We collected 143 valid questionnaires, related to 63 men and 80 women, aged 34-99 years (mean, 71.8 years). The question concerning headache had the lowest sensitivity and specificity, respectively 57.1% and 36.5%, and the question concerning leg palsy had the highest sensitivity and specificity, respectively 82.0% and 52.4%. Multivariate analysis identified questions on facial and leg palsy as independent predictors of a final diagnosis of stroke. A few questions on motor deficits proposed by emergency medical service operators may be useful in the pre-hospital identification of stroke patients. Concordance of any questions versus final diagnosis of stroke was, however, far to be satisfying. Thus, our experience supports the need for an educational program to improve the efficiency of a pre-hospital diagnosis of stroke.

Adult↗

Otx genes in the development and evolution of the vertebrate brain.

Most of the gene candidates for the control of developmental programmes that underlie brain morphogenesis in vertebrates are the orthologues of Drosophila genes coding for signalling molecules or transcription factors. Among these, the orthodenticle group, including the Drosophila orthodenticle (otd) and the vertebrate Otx1 and Otx2 genes, is mostly involved in fundamental processes of anterior neural patterning. In mouse, Drosophila and intermediate species otd/Otx genes have shown a remarkable similarity in expression pattern suggesting that they could be part of a conserved control system operating in the brain and different from that coded by the HOX complexes controlling the hindbrain and spinal cord. In order to verify this hypothesis, a series of mouse models have been generated in which the functions of the murine Otx genes were: (i) fully inactivated, (ii) replaced with each other, and (iii) replaced with the Drosophila otd gene. The data obtained highlight a crucial role for the Otx genes in specification, regionalization and terminal differentiation of rostral central nervous system and lead to hypothesize that modification of their regulatory control may have influenced the morphogenesis and evolution of the brain.

Alleles↗

Otx genes are required for tissue specification in the developing eye.

Patterning of the vertebrate eye appears to be controlled by the mutual regulation and the progressive restriction of the expression domains of a number of genes initially co-expressed within the eye anlage. Previous data suggest that both Otx1 and Otx2 might contribute to the establishment of the different eye territories. Here, we have analysed the ocular phenotype of mice carrying different functional copies of Otx1 and Otx2 and we show that these genes are required in a dose-dependent manner for the normal development of the eye. Thus, all Otx1(-/-); Otx2(+/-) and 30% of Otx1(+/-); Otx2(+/-) genotypes presented consistent and profound ocular malformation, including lens, pigment epithelium, neural retina and optic stalk defects. During embryonic development, optic vesicle infolding was severely altered and the expression of pigment epithelium-specific genes, such as Mitf or tyrosinase, was lost. Lack of pigment epithelium specification was associated with an expansion of the prospective neural retina and optic stalk territories, as determined by the expression of Pax6, Six3 and Pax2. Later in development the presumptive pigment epithelium region acquired features of mature neural retina, including the generation of Islet1-positive neurones. Furthermore, in Otx1(-/-); Otx2(+/-) mice neural retina cell proliferation, cell differentiation and apoptotic cell death were also severely affected. Based on these findings we propose a model in which Otx gene products are required for the determination and differentiation of the pigment epithelium, co-operating with other eye patterning genes in the determination of the specialised tissues that will constitute the mature vertebrate eye.

Animals↗

Forebrain and midbrain development requires epiblast-restricted Otx2 translational control mediated by its 3' UTR.

Otx genes play an important role in brain development. Previous mouse models suggested that the untranslated regions (UTRs) of Otx2 mRNA may contain regulatory element(s) required for its post-transcriptional control in epiblast and neuroectoderm. In order to study this, we have perturbed the 3' UTR of Otx2 by inserting a small fragment of DNA from the lambda phage. Otx2(lambda) mutants exhibited proper gastrulation and normal patterning of the early anterior neural plate, but from 8.5 days post coitum they developed severe forebrain and midbrain abnormalities. OTX2 protein levels in Otx2(lambda) mutants were heavily reduced in the epiblast, axial mesendoderm and anterior neuroectoderm but not in the visceral endoderm. At the molecular level, we found out that the ability of the Otx2(lambda) mRNA to form efficient polyribosome complexes was impaired. Sequence analysis of the Otx2-3' UTR revealed a 140 bp long element that is present only in vertebrate Otx2 genes and conserved in identity by over 80%. Our data provide experimental evidence that murine brain development requires accurate translational control of Otx2 mRNA in epiblast and neuronal progenitor cells. This leads us to hypothesise that this control might have important evolutionary implications.

3' Untranslated Regions↗

Regionalisation of anterior neuroectoderm and its competence in responding to forebrain and midbrain inducing activities depend on mutual antagonism between OTX2 and GBX2.

The anterior neural ridge (ANR), and the isthmic organiser (IsO) represent two signalling centres possessing organising properties necessary for forebrain (ANR) as well as midbrain and rostral hindbrain (IsO) development. An important mediator of ANR and IsO organising property is the signalling molecule FGF8. Previous work has indicated that correct positioning of the IsO and Fgf8 expression in this domain is controlled by the transcription factors Otx2 and Gbx2. In order to provide novel insights into the roles of Otx2 and Gbx2, we have studied mutant embryos carrying different dosages of Otx2, Otx1 and Gbx2. Embryos deficient for both OTX2 and GBX2 proteins (hOtx1(2)/hOtx1(2); Gbx2(-/-)) show abnormal patterning of the anterior neural tissue, which is evident at the presomite-early somite stage prior to the onset of Fgf8 neuroectodermal expression. Indeed, hOtx1(2)/hOtx1(2); Gbx2(-/-) embryos exhibit broad co-expression of early forebrain, midbrain and rostral hindbrain markers such as hOtx1, Gbx2, Pax2, En1 and Wnt1 and subsequently fail to activate forebrain and midbrain-specific gene expression. In this genetic context, Fgf8 is expressed throughout the entire anterior neural plate, thus indicating that its activation is independent of both OTX2 and GBX2 function. Analysis of hOtx1(2)/hOtx1(2); Gbx2(-/-) and Otx1(+/-); Otx2(+/-) mutant embryos also suggests that FGF8 cannot repress Otx2 without the participation of GBX2. Finally, we report that embryos carrying a single strong hypomorphic Otx2 allele (Otx2(lambda)) in an Otx2 and Gbx2 null background (Otx2(lambda)/-; Gbx2(-/-)) recover both the headless phenotype exhibited by Otx2(lambda)/- embryos and forebrain- and midbrain-specific gene expression that is not observed in hOtx1(2)/hOtx1(2); Gbx2(-/-) mutants. Together, these data provide novel genetic evidence indicating that OTX2 and GBX2 are required for proper segregation of early regional identities anterior and posterior to the mid-hindbrain boundary (MHB) and for conferring competence to the anterior neuroectoderm in responding to forebrain-, midbrain- and rostral hindbrain-inducing activities.

Animals↗

OTD/OTX2 functional equivalence depends on 5' and 3' UTR-mediated control of Otx2 mRNA for nucleo-cytoplasmic export and epiblast-restricted translation.

How gene activity is translated into phenotype and how it can modify morphogenetic pathways is of central importance when studying the evolution of regulatory control mechanisms. Previous studies in mouse have suggested that, despite the homeodomain-restricted homology, Drosophila orthodenticle (otd) and murine Otx1 genes share functional equivalence and that translation of Otx2 mRNA in epiblast and neuroectoderm might require a cell type-specific post-transcriptional control depending on its 5' and 3' untranslated sequences (UTRs). In order to study whether OTD is functionally equivalent to OTX2 and whether synthesis of OTD in epiblast is molecularly dependent on the post-transcriptional control of Otx2 mRNA, we generated a first mouse model (otd(2)) in which an Otx2 region including 213 bp of the 5' UTR, exons, introns and the 3' UTR was replaced by an otd cDNA and a second mutant (otd(2FL)) replacing only exons and introns of Otx2 with the otd coding sequence fused to intact 5' and 3' UTRs of Otx2. otd(2) and otd(2FL) mRNAs were properly transcribed under the Otx2 transcriptional control, but mRNA translation in epiblast and neuroectoderm occurred only in otd(2FL) mutants. Phenotypic analysis revealed that visceral endoderm (VE)-restricted translation of otd(2) mRNA was sufficient to rescue Otx2 requirement for early anterior patterning and proper gastrulation but it failed to maintain forebrain and midbrain identity. Importantly, epiblast and neuroectoderm translation of otd(2FL) mRNA rescued maintenance of anterior patterning as it did in a third mouse model replacing, as in otd(2FL), exons and introns of Otx2 with an Otx2 cDNA (Otx2(2c)). The molecular analysis has revealed that Otx2 5' and 3' UTR sequences, deleted in the otd(2) mRNA, are required for nucleo-cytoplasmic export and epiblast-restricted translation. Indeed, these molecular impairments were completely rescued in otd(2FL) and Otx2(2c) mutants. These data provide novel in vivo evidence supporting the concept that during evolution pre-existing gene functions have been recruited into new developmental pathways by modifying their regulatory control.

3' Untranslated Regions↗

Membrane-anchorage of Cripto protein by glycosylphosphatidylinositol and its distribution during early mouse development.

cripto is the original member of the family of EGF-CFC genes, recently recognized as novel extracellular factors essential for vertebrate development. During the early stages of mouse gastrulation, cripto mRNA is detected in mesodermal cells; later, cripto mRNA is detected only in the truncus arteriosus of the developing heart. Here we describe the in vivo distribution of Cripto protein throughout mouse embryo development and show that cripto mRNA and protein colocalize. By means of immunofluorescence analysis and biochemical characterization, we show that Cripto is a membrane-bound protein anchored to the lipid bilayer by a glycosylphosphatidylinositol (GPI) moiety. We suggest that presentation of Cripto on the cell surface via a GPI-linkage is important in determining the spatial specificity of cell-cell interactions that play a critical role in the early patterning of the embryo.

Animals↗

The emergency department gynaecologist and emergency postcoital contraception.

The emergency department gynaecologist is often faced with requests for emergency postcoital contraception. The physician on duty is usually very busy and does not always have enough time to perform a complete evaluation of the woman's state of health. The emergency gynaecologist who prescribes postcoital contraception also has a number of other problems to cope with in regard to the pharmacological preparations on the market, the efficacy of various methods, the monitoring of side-effects which are not, always, tolerated by all patients and the outcome of his therapeutic prescription. All these aspects should be emphasized in the "first aid" counselling offered to the patients. In conclusion, we consider that any women who decides to use postcoital contraception should have the right to receive assistance of guaranteed quality throughout the period that elapses between taking the drug and the subsequent menstrual cycle. This is not strictly guaranteed by an emergency gynaecological service.

Contraceptives, Postcoital↗

Pulmonary function and metabolic physiology of theropod dinosaurs

Ultraviolet light analysis of a fossil of the theropod dinosaur Scipionyx samniticus revealed that the liver subdivided the visceral cavity into distinct anterior pleuropericardial and posterior abdominal regions. In addition, Scipionyx apparently had diaphragmatic musculature and a dorsally attached posterior colon. These features provide evidence that diaphragm-assisted lung ventilation was present in theropods and that these dinosaurs may have used a pattern of exercise physiology unlike that in any group of living tetrapods.

Journal Article↗

[Critical review of colpo-histological results in cervix pathology].

BACKGROUND: The objective of this paper was to evaluate the role of squamous metaplasia in the determination of certain colposcopic appearances. METHODS: One thousand four hundred and six infertile outpatients, attending assisted reproduction techniques, underwent a "first level" colposcopy. Two hundred fifty nine abnormal transformation zones were biopsied and the histologic diagnoses were subdivided as follows: squamous metaplasia, squamous metaplasia + koilocytosis, isolated koilocytosis, condyloma, CIN + HPV, cervicitis. RESULTS: Two hundred forty seven cases out of 259 biopsied colposcopic findings (95.4%) were colposcopically classified as grade 1 abnormal transformation zone (thin white epithelium, regular mosaic and punctuation). The correlation between 247 grade 1 abnormal transformation zone colposcopic patterns and histologic diagnosis revealed 105 (42.5%) histologic findings described as squamous metaplasia that resulted immature in 63% of these samples. Between 132 (53.4%) cases that presented a pattern of human papillomavirus infection (condyloma, squamous metaplasia + koilocytosis or isolated koylocitosis), quite two thirds (62%) were described as condylomas, one third (31%) as squamous metaplasia associated with koylocitosis and only 7% as isolated koylocitosis. In conclusion, 42.5% of target biopsies performed on low grade abnormal transformation of the cervix revealed squamous metaplasia, more than half of them revealed one of HPV infection forms, while only 2% represented cervical intraepithelial neoplasia. CONCLUSIONS: Among the low risk female population, one out of two cases of colposcopically low grade pattern should be considered indicative of squamous metaplasia. The results obtained confirm that colposcopic evaluation is unable to distinguish between immature metaplastic transformation of the epithelium and metaplastic epithelium with initial neoplastic transformation.

Biopsy↗