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Biomedical subjects

S Fontana

Publications and source records attributed to S Fontana.

At least 19 recordsLinked to original sources
PubMed2001

Development and validation of a high-performance liquid chromatography-tandem mass spectrometry assay for the determination of sanfetrinem in human plasma.

A rapid, selective and accurate high-performance liquid chromatography-tandem mass spectrometry assay for the quantification of sanfetrinem in human plasma has been developed and validated. The performance of manual and automated sample preparation was assessed; 50 microl of plasma sample was deproteinized with acetonitrile, followed by dilution with water and injection onto the LC system. Chromatographic separation was achieved on a Phenomenex Luna C18(2), 50x2.0 (5 microm) column with a mobile phase consisting of water-acetonitrile with 0.1% formic acid followed by detection with a Perkin-Elmer API3000 mass spectrometer in multiple reaction monitoring mode. The lower limit of quantification was improved by five times compared to the UV method previously reported. A range of concentration from 10 ng/ml to 5 microg/ml was covered. The method was applied to the quantification of sanfetrinem in human plasma samples from healthy volunteers participating in a clinical study.

Anti-Bacterial Agents↗
PubMed2001

Requirement for leptin in the induction and progression of autoimmune encephalomyelitis.

Recent evidence indicates that leptin modifies T cell immunity, and may provide a key link between nutritional deficiency and immune dysfunction. To study the influence of leptin on autoimmunity, susceptibility to experimental autoimmune encephalomyelitis induced by immunization with a myelin-derived peptide was examined in leptin-deficient, C57BL/6J-ob/ob mice, with or without leptin replacement, and in wild-type controls. Leptin replacement converted disease resistance to susceptibility in the C57BL/6J-ob/ob mice; this was accompanied by a switch from a Th2 to Th1 pattern of cytokine release and consequent reversal of Ig subclass production. Our findings suggest that leptin is required for the induction and maintenance of an effective proinflammatory immune response in the CNS.

Adoptive Transfer↗
PubMed2001

Leptin potentiates experimental autoimmune encephalomyelitis in SJL female mice and confers susceptibility to males.

SJL (H-2s) female mice are more susceptible than males to experimental autoimmune encephalomyelitis (EAE) induced by immunization with myelin-derived peptides. The reasons for this sexual dimorphism are unclear, but may include such factors as sex-related differences in immune responsiveness, hormonal effects and sex-linked genetic factors. Recent evidence indicates that leptin modifies T cell immunity promoting T helper (Th) 1 pro-inflammatory immune responses. Circulating leptin levels show a marked sexual dimorphism, being higher in females than in males. In the present study, we investigated whether leptin treatment altered the course of relapsing-remitting EAE, induced by the proteolipid protein peptide (PLP(139-151)), in SJL susceptible females and EAE-resistant males. Administration of leptin to female SJL mice before or after disease onset significantly worsened the disease, with a concomitant increase in the PLP(139-151)-specific delayed-type hypersensitivity (DTH) reactivity and in vitro IFN-gamma secretion. Leptin treatment at priming with antigen or before disease onset rendered male SJL mice susceptible to EAE, with the appearance of PLP(139-151)-specific DTH reactivity and a switch from a Th2 to Th1 pattern of cytokine release. Our findings indicate that leptin administration to susceptible females resulted in a more severe disease, and that reduced leptin levels in male SJL mice may contribute to the gender-related differences in the induction phase of EAE.

Amino Acid Sequence↗
PubMed2001

Zymographic analysis of circulating and tissue forms of colon carcinoma gelatinase A (MMP-2) and B (MMP-9) separated by mono- and two-dimensional electrophoresis.

Gelatinase A (MMP-2) and gelatinase B (MMP-9) play a key role in the proteolytic cascade leading to ECM degradation during invasion and metastasis. The enzyme activity is regulated both at the intra- and extra-cellular level. Extracellular regulation is achieved mainly through the balance between proenzyme activation and inhibition, which appears to be altered in cancer patients. One of the mechanisms of MMP inhibition is the binding of the enzymes to appropriate tissue inhibitors (TIMP). In the recent literature, it has been suggested that MMP-2 and/or MMP-9 are indeed over-produced in many carcinomas, while the identity of the various enzymatic forms (latent, activated and enzyme/inhibitor complexes) remains to be elucidated. In this study we have analyzed the circulating forms of MMP-9 and MMP-2 in serum samples of patients with colon carcinoma, as well as the enzymatic activities present in tissue extracts from surgical fragments (primary tumor and its paired healthy tissue). Proteins were separated by means of mono-dimensional or bidimensional electrophoresis, and the enzymes detected by gelatin zymography and immunological assays. The results of densitometric analyses demonstrate that proMMP-9, but not proMMP-2, is significantly higher in the oncologic sera vs. the normal sera. In addition, several oligomeric circulating and tissue forms of MMP-9 are preferentially found in the oncologic samples, both in mono- and second-dimension zymograms. The activated forms of MMP-2 and MMP-9 are uniquely present in the primary tumor extracts, thus confirming the involvement of the tissue microenvironment in gelatinase activation and function.

Adult↗
PubMed2001

Microangiopathic haemolytic anaemia in metastasizing malignant tumours is not associated with a severe deficiency of the von Willebrand factor-cleaving protease.

Complete deficiency of von Willebrand factor-cleaving protease (VWF-cp) has recently been identified as a pathogenetically important factor for thrombotic thrombocytopenic purpura (TTP). Microangiopathic haemolytic anaemia (MAHA) with thrombocytopenia in patients with metastasizing neoplasms is clinically similar to TTP, however, the pathogenesis of the condition is unclear. Partial deficiency of VWF-cp in metastasizing malignancy has recently been reported in patients without MAHA. Our study shows normal or subnormal VWF-cp activity in four patients with metastasizing neoplasia-associated MAHA but, in contrast to classical TTP, no complete deficiency of VWF-cp despite the full clinical picture of MAHA.

ADAM Proteins↗
PubMed2001

The fine specificity of human T cell lines towards myelin basic protein peptides in southern Italian multiple sclerosis patients.

We studied the relationship between the HLA specificities associated with multiple sclerosis (MS) susceptibility in southern Italy and the reactivity of the human myelin basic protein (hMBP) immunogenic peptides 84-98 and 143-168, using short-term T-cell lines established from 9 MS patients and from 8 healthy individuals. In our population, DR15 was significantly associated with MS (34.9% in MS versus 13.7% in healthy controls, P < 0.05). This result is in agreement with the association found in northern Europe, but not with data obtained in a population from the island of Sardinia (Italy). In MS patients the frequency of reactive T-cell lines (TCL), tested for fine specificity against the immunodominant hMBP peptides 84-98 and 143-168, was increased for the hMBP 143-168 peptide (P < 0.05) but not for the 84-98 peptide. Although this reactivity was higher in DR15+ MS patients than in DR 15- MS patients, it seemed not to be associated with DR15 specificity in the MS population. Furthermore, there were no significant differences in frequency of reactive TCL to hMBP peptide 84-98 in DR15-positive or DR15-negative MS patients. Consequently, it appears that peptide 84-98, considered as a relevant autoantigen, is not implicated in the pathogenesis of MS in our population from southern Italy.

Autoantigens↗
PubMed2001

Is melatonin circadian rhythm a physiological feature associated with healthy longevity? A study of long-living subjects and their progeny.

The study investigates the circadian rhythm (CR) of urinary 6-sulphatoxy-melatonin (aMT6s) in long-living (longevous) subjects and their progeny. The aim is to detect whether or not the melatonin CR is a physiological feature associated with healthy longevity. The aMT6s CR was investigated in 10 longevous subjects, 8 of their children and 9 of their grandchildren, all in good health. Control data were obtained respectively from 13 adult subjects and 9 young subjects, in good health, but characterized by a negative family history for longevity. All the subjects were born and living in the same city. The study was performed in the summer of 1996. The aMT6s CR was found to persist in longevous subjects, being characterized by a lower mesor and amplitude. The aMT6s CR was found not to show properties consistently different in children and grandchildren as compared respectively to their adult and young controls. Because of its preservation in longevous subjects, it can be argued that the melatonin CR is a physiological feature associated with healthy longevity. Because of the comparability of aMT6s CR in children and grandchildren, with respect to their controls without a positive family history of longevity, it can be argued that the melatonin CR is not a marker that can be used for an earlier identification of the candidates for longevity.

Adult↗
PubMed2000

Linear transgene constructs lacking vector backbone sequences generate low-copy-number transgenic plants with simple integration patterns.

Whole plasmids are used in both Agrobacterium-mediated transformation and direct DNA transfer, generally leading to the integration of vector backbone sequences into the host genome along with the transgene(s). This is undesirable, as vector backbone sequences often have negative effects on transgene or endogenous gene expression, and can promote transgene rearrangements. We, therefore, bombarded rice tissue with two constructs: a plasmid containing the bar gene, and a linear DNA fragment isolated from the same plasmid, corresponding to the minimal bar gene expression cassette (promoter, open reading frame and terminator). We recovered phosphinothricin-resistant plants from both experiments, showing that the selectable marker was efficiently expressed. Transformation with such constructs resulted in predominantly 'simple' integration events (one or two bands on Southern blots), producing low-copy-number transgenic plants with a low frequency of transgene rearrangements. Conversely, transformation with supercoiled or linearized whole plasmids generated plants with 'complex' integration patterns, that is, higher copy numbers and frequent transgene rearrangements. We monitored transgenic lines through to the R4 generation and observed no silencing in plants carrying minimal constructs. We also carried out experiments in which rice tissue was simultaneously bombarded with minimal linear hpt and gusA cassettes. We observed robust GUS activity in hygromycin-resistant plants, confirming co-expression of the selectable and nonselectable markers. Furthermore, the efficiency of cotransformation using minimal constructs was the same as that using supercoiled plasmid cointegrate vectors.

Acetyltransferases↗
PubMed2000

HLA class I antigen downregulation by interleukin (IL)-10 is predominantly governed by NK-kappaB in the short term and by TAP1+2 in the long term.

The present study was designed to determine the molecular mechanisms by which interleukin (IL)-10 prevents the HLA class I antigen expression at the cell surface. In this context, the potential role of transporter associated with antigen presentation 1+2 (TAP1+2) molecules and NF-kappaB transcription factors was addressed. The IL-10 effect was investigated in a human lymphoblastoid cell system defective for TAP1+2 genes (T2 cell line) and in the related TAP1+2 transfectants (T3 cell line). In this experimental system, after 48 h of incubation in the presence of IL-10, the HLA class I antigen downmodulation was observed in the T3 but not in the T2 cell line, suggesting a potential role of TAP1+2 molecules. In the same experimental conditions, the NF-kappaB activity was unaffected. Instead, after 3 h of exposure to IL-10, the HLA downmodulation was observed in both cell lines, the NF-kappaB factors activity being strongly reduced. In addition, the transfection of the inhibitor of NF-kappaB, IkappaBalpha, prevented the IL-10 effect on HLA class I antigen expression in the T3 cell line. This phenomenon was observed after 3 h but not 48 h of IL-10 incubation. These evidences indicate a time dependent involvement of TAP1+2 antigens and of NF-kappabeta activity in the IL-10-induced major histocompatibility complex (MHC) class I downmodulation.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Increased leptin levels in serum and peritoneal fluid of patients with pelvic endometriosis.

Pelvic endometriosis is an immune-related chronic inflammatory disease, characterized by ectopic implants of endometrium in the peritoneal cavity and associated with increased secretion of proinflammatory cytokines and neoangiogenesis. Leptin, the adipocyte-derived hormone, has been shown to have a role in food intake, basal metabolism, and reproductive function. Leptin levels are dynamically regulated, being elevated by inflammatory mediators and reduced by starvation. Leptin itself can influence the proinflammatory immune responses of CD4+ T lymphocytes, and reports have also shown this hormone to be an angiogenic factor in vitro and in vivo. We investigated whether leptin concentrations in serum and peritoneal fluid (PF) differed between 13 patients with different stages of endometriosis and 15 age- and body mass index-matched controls. We found a statistically significant (P < 0.05) increase in leptin levels in serum (30.3 +/- 14.8 ng/mL) and PF (35.9 +/- 17.4 ng/mL) of patients with endometriosis, compared with our control population (serum, 15.6 +/- 8.4; PF, 17.5 +/- 7.2 ng/mL). Regression equations, relating leptin to body mass index, were also significantly different in endometriosis patients, compared with controls. Higher levels of leptin were observed in the earlier stages of endometriosis than advanced-stage disease. These data suggest that the proinflammatory and neoangiogenic actions of leptin may contribute to the pathogenesis of endometriosis.

Adult↗
PubMed1999

Role of iron in asbestos-body-induced oxidant radical generation.

Asbestos bodies (AB) were harvested from human lung tissue digests and isolated from uncoated asbestos fibers. Samples containing 1000 AB were added to a reactive solution to investigate the ability of AB to oxidize deoxy-D-ribose and generate reactive oxygen species (ROS) in the presence of ascorbate and hydrogen peroxide as determined by formation of thiobarbituric acid (TBA)-reactive products. Three types of asbestos fibers were tested for comparison, since they are known to be able to produce ROS. The absorbance values measured with 1000 AB were significantly higher than those observed with 1000 fibers of the three types of asbestos. Since in our reaction system the only source of transition metals was the iron-rich AB, data suggest iron derived from the ferritin coating of AB was involved in oxidant generation. Addition of iron to AB enhanced TBA-reactive product formation, while chelation of Fe with deferoxamine reduced this reaction. Hydroxyl radical scavengers 1,3-dimethyl-2-thiourea (DMTU) and mannitol (MN) also effectively blocked TBA-reactive product generation. Data indicate the importance of Fe in AB-induced oxidant damage. With the addition of polymorphonuclear leukocytes (PMN) to AB, incubation in the reactive solution gave very high amounts of TBA-reactive products, but using a reactive solution devoid of ascorbate, very low amounts of TBA-reactive products were generated. In the latter condition, the superoxide of cell membranes probably reduced and removed iron from AB-coating ferritin, but less effectively than ascorbate. Further after the possible reoxidation of Fe2+, Fe3+ could be coordinated by lactoferrin. Since such availability of reductant is never approached in living systems, the iron in the AB coating is unlikely to function as a catalyst of Fenton-type reactions in vivo.

Asbestos↗
PubMed1999

Daily hunger sensation and body compartments: II. Their relationships in obese patients.

Hunger sensation (HS) is a signal whose levels change during the 24-h day. The daily mean level of HS was correlated with the human body compartments, as investigated by bioelectrical impedance analysis, to detect the relationship between the orectic perception and both the free fat mass (FFM) and the fat body mass (FBM) in 22 clinically healthy subjects (CHS) (2 M, 20 W, BMI: 18.5-24.0 kg/m2) and 48 obese patients (OP) (4 M, 44 W, BMI: 25.2-54.7 kg/m2). In CHS, the daily mean level of HS correlated positively with the FFM and negatively with the FBM. These correlations were not present in OP. This lack of relationships between HS and the body compartments where energy is maximally consumed (i.e., the FFM) and maximally stored (i.e., the FBM) indicates that the orectic response to energy expenditure and the orectic inhibition to fat accumulation are feedback mechanisms which are impaired in obesity.

Adipose Tissue↗
PubMed1999

Anxiety, depression, hunger and body composition: III. Their relationships in obese patients.

The present paper explores the relationships between anxiety, depression, hunger sensation and body composition in obese patients (OP). The aim is to detect whether or not there are abnormalities in these relationships in OP as compared to clinically healthy subjects (CHS). The study was performed on 22 CHS (2 M, 20 W; mean age = 24 +/- 2 years; mean body mass index = 21 +/- 2 kg/m2) and 48 OP (4 M, 44 W; mean age = 40 +/- 17 years; mean body mass index = 32 +/- 7 kg/m2). Anxiety and depression were found to be correlated, negatively, with the relative lean body mass, and, positively, with the fat body mass in OP but not in CHS. These findings corroborate the idea that anxiety and depression can reach an abnormal expression when obesity shows its worst loss in lean body mass and its highest expansion in adipocyte mass. As hunger sensation was found not to correlate with either anxiety or depression in OP, the opinion is expressed that the impairment of anxio-depressive integrity is a corollary of obesity rather than a primary affective disorder leading to obesity via an enhanced food intake.

Adult↗
PubMed1999

[Derailed oral anticoagulation with very high INR values and poor response to oral vitamin K--cholestasis as a possible cause].

A 76-year-old man under long term oral anticoagulant treatment showed unclottable prothrombin time (PT) without overt bleeding. After oral administration of vitamin K1, PT remained severely prolonged and the patient was hospitalized. INR was 8.0 and responded to parenteral vitamin K. Cholestasis resulting in poor intestinal vitamin K resorption was assumed to have caused "overanticoagulation". Quick test is a global clotting test for the extrinsic and common pathways of the coagulation system. Increased PT, i.e. decreased Quick percentage, may be due to different conditions and should--if unexplained--be further analyzed by assaying factors II, V, VII, X and fibrinogen. Preanalytical problems, plasma dilution with clotting factor-free volume replacement, decreased vitamin K-dependent clotting factors (oral anticoagulation, intoxication with certain rodenticides, vitamin K deficiency), impaired liver synthetic capacity, disseminated intravascular coagulation, or massive heparin contamination may cause prolonged PT. Newborns physiologically have longer PT and should receive vitamin K prophylaxis.

Administration, Oral↗
PubMed1999

[Chronic, hemorrhage-induced iron deficiency anemia in Osler disease].

We report the history of a 77-year-old man with Osler-Weber-Rendu disease (hereditary hemorrhagic telangiectasia) who suffered from recurrent epistaxis and chronic bleeding anemia for many years. Hereditary hemorrhagic telangiectasia is a rare congenital disease, that is characterized by telangiectases of the nasal and oral mucosa, the gastrointestinal tract and the skin. Arteriovenous malformations of the lung and the brain may be present. The genetic and pathologic features, the clinical manifestations and the differential diagnosis are shortly presented. The management is not validated by controlled studies and is mainly based on clinical experience. It involves supportive therapy with iron supplementation and erythrocyte transfusions, if needed, for chronic bleeding anemia, aminocaproic acid, tranexamic acid or oestrogen-progesterone therapy to prevent mucosal bleeding, cauterisation, photocoagulation, transcatheter embolotherapy or surgery to treat the vascular abnormalities.

Aged↗
PubMed1998

Hunger sensation: a chronobiometric approach to its within-day and intra-day recursivity in anorexia nervosa restricting type.

Hunger sensation (HS) is a perception with a daily (circadian) and within-day (ultradian) recursive pattern. In human beings, circadian repeatability was investigated by means of the Single Cosinor method, while the ultradian recursivity was investigated by means of the spectral analysis, both applied to the 24-h HS profile (orexigram). Orexigrams were provided by each subject investigated, who self-rated her subjective orectic stimulus (OS) (from 1 to 10 hunger units) every half hour. The study was performed in 19 female patients aged 13-52 newly diagnosed as in the first episode of Anorexia Nervosa Restricting Type, with a BMI below 18.7. The control group consisted of 10 clinically healthy women aged 21 to 52 years with a BMI from 23 to 25. Two types of orexigrams were found. The first was characterized by a low profile with negligible ultradian variability, in which the HS circadian rhythm (CR) was still detectable, but the power spectrum (PS) was composed of unusual ultradian components associated with a very diminished amplitude for the circadian harmonics. The second was characterized by an almost regular profile, in which the ultradian variability was clearly detectable, the CR regularly fluctuated, and the PS was almost regularly composed. These findings indicate that anorectic patients (AP) can be recognized by their orexigram as "hyporectic", or "eurectic". Therefore, the term "anorexia" seems to be appropriate for AP who exhibit the first type of orexigram (anorectic aphagia nervosa), whereas the second identifying those who could be defined as suffering from "eurectic aphagia nervosa".

Activity Cycles↗
PubMed1998

Daily hunger sensation and body composition: I. Their relationships in clinically healthy subjects.

The human hunger sensation (HS) is a perceptive signal characterized by day-night variability (DNV). This pattern was investigated with respect to its relations with the body compartments in 22 clinically healthy subjects (CHS, 11 males and 11 females, mean age: 24 +/- 2.5 years, mean BMI: 21 +/- 1.7). The DNV was investigated by means of conventional descriptive statistics and the single cosinor method (SCM). Both procedures were applied to the orexigram, i.e., the 24-h profile of the orectic stimulus (OS) provided by each subject, who self-rated his/her HS (from 1 to 10 hunger units) every half hour. Body composition was investigated by Bioelectrical Impedance Analysis (BIA) on the day when the orexigrams were compiled. It was found that the daily HS level correlates positively with the Free Fat Body Mass (FFBM) and negatively with the Fat Body Mass (FBM). These opposite relations indicate that HS is stimulated by the needs of the FFBM, and inhibited by expansion of the FBM, and provide further evidence of the existence of an "adipostat" anorectic mechanism.

Adult↗