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Biomedical subjects

M Bianchi

Publications and source records attributed to M Bianchi.

At least 109 records · Page 6Linked to original sources
PubMed1998

Ultrasonic myocardial texture in hypertensive mild-to-moderate left ventricular hypertrophy: a videodensitometric study.

Myocardial texture analysis of two-dimensional echocardiographic gray level distribution is abnormal in hypertensive patients with severe increase of left ventricular mass. The aim of this study was to investigate the behavior of this parameter in hypertensive patients with absent-to-moderate left ventricular hypertrophy, more representative of the overall hypertensive population. We compared male essential hypertensive patients, with absent or mild-to-moderate left ventricular hypertrophy, with normotensive sedentary healthy subjects as controls. The groups (n = 18 each) were age- (+/- 2 years) and sex-matched. All subjects performed ambulatory blood pressure measurements for the evaluation of 24 h mean systolic and diastolic blood pressure. Quantitative analysis of echocardiographic digitized imaging was performed through a calibrated 256 gray level digitization system to calculate midseptum and midposterior end-diastolic and end-systolic first and second order textural analysis. In particular were observed the mean gray level cyclic variations to deriving the cyclic variation index (CVI). The hypertensives showed a significantly lower CVI compared with controls both for septum (P < .001) and for posterior wall (P < .0001). No significant relationships were found between CVI and relative diastolic thickness both of septum and posterior wall. Conversely, a significant inverse relationship was found between systolic arterial pressure values and CVI both of septum and posterior wall. Abnormalities of two dimensional echocardiographic gray level distribution are present also in hypertensive patients with absent or with mild-to-moderate levels of left ventricular hypertrophy, but seem unrelated to the degree of echocardiographic hypertrophy as such. Changes in collagen network distribution or microcirculatory alterations, secondary to pressure-volume overload per se or to other complex humoral factors, could explain these abnormalities. Further work is needed to establish the clinical, therapeutic, and prognostic implications of these findings.

Adult↗
PubMed1998

Enzymatic properties of overexpressed human hexokinase fragments.

Full-length hexokinase (HK; ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1), a truncate form of the enzyme lacking the first 11 amino acids (HK-11aa) and the 50 kDa C-terminal half ('mini'-HK) containing the catalytic domain, were overexpressed and purified to homogeneity to investigate the influence of the N-terminal region of human hexokinase type I (HK) on its regulatory properties. All forms of the enzyme are catalytically active with the HK-11aa being the most active. All the forms of HK showed the same affinity for glucose and MgATP and were also inhibited by glucose 6-phosphate (Glc 6-P) competitively vs. MgATP with similar Kis (28.5-37 microM). Glucose 1,6-bisphosphate (Glc 1,6-P2) was also a strong inhibitor of all HKs without significant differences among the different truncate forms of the enzyme (Kis 49.5-59 microM). At low concentrations (0-3 mM), Pi was able to reverse the sugar phosphate inhibition of the full-length HK and HK-11aa but not of the 'mini'-HK. In contrast, at high concentrations Pi was an inhibitor of all the hexokinases investigated. These findings confirm that Pi has a low affinity binding site on the C-terminal of HK while counteracts glucose 6-phosphate inhibition by binding to or requiring the N-terminal half of the enzyme. The first 11 N-terminal amino acids influence the specific activity of HK but are unable to affect the kinetic properties investigated.

Dose-Response Relationship, Drug↗
PubMed1998

Behavioural characterization of interleukin-6 overexpressing or deficient mice during agonistic encounters.

Interleukin-6 (IL-6) is a cytokine released by activated immune cells which has been shown to affect brain function. In this experiment aggressive and affiliative behaviour exhibited during agonistic encounters by transgenic male mice either not expressing (IL-6 -/-) or overexpressing (NSE-hIL-6) IL-6 in the central nervous system was investigated. All subjects were isolated for 24 days before the aggressive encounter and were 52 days old at the time of testing. Subjects were placed for 5 consecutive days in a neutral cage for 15 min with an opponent of the Balb/c strain that had been previously isolated for the same amount of time. The first and the last test sessions were videotaped to evaluate the first approach and the establishment of the social role, respectively. A number of behavioural categories were later scored. When compared with wild-type controls, IL-6 -/- mice showed a higher degree of aggressive behaviour as indicated by a higher frequency of Offensive Upright Posture, an effect more pronounced on the fifth encounter. On the contrary, NSE-hIL-6 subjects showed a tendency to be more involved in affiliative-type social interactions, displaying a higher frequency and duration of behaviours such as Anogenital, Nose or Body Sniff. IL-6 -/- mice showed a clear tendency to exhibit less affiliative interactions compared with their controls while dopamine levels were found to be modified in a number of brain regions in these mice. Overall, these data suggest that IL-6 affects both aggressive and affiliative-type interactions, although the behaviour of the NSE-hIL-6 subjects was less affected than that of the IL-6 -/- group. The effects of the genetic background of the animal in screening the outcome of gene manipulations on behaviour are also discussed.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1998

Some applications of solid phase micro extraction (SPME) in the analysis of pesticide residues in food.

The Solid Phase Micro-Extraction (SPME) technique was applied to analyze chlorpropham in potatoes and amitraz in honey. The homogenized sample, suspended in water and stirred, was extracted with a 100 microns thick polidimetylsiloxane fiber and desorbed into the injection port of a gas chromatograph/mass-spectrometer (quadrupole) operating in single ion monitoring. Sensitivities down to 0.01 mg/Kg and linear responses in the range of 0.01-0.1 mg/Kg were obtained. The results of SPME pesticide residue analysis in potatoes corresponded to those obtained with a traditional multiresidue method.

Chlorpropham↗
PubMed1998

CNI-1493 prolongs survival and reduces myocyte loss, apoptosis, and inflammation during rat cardiac allograft rejection.

Cytokines and cytotoxic agents, including nitric oxide (NO) released by macrophages, play important roles during cardiac allograft rejection. In contrast to agents that suppress T-lymphocyte function, CNI-1493 is a multivalent guanylhydrazone compound that inhibits the synthesis and release of proinflammatory cytokines and NO from macrophages. This study investigated the effects of CNI-1493 on rejecting rat cardiac allografts by using Lewis to Wistar-Furth heterotopic cardiac transplants. CNI-1493 (2 mg/kg i.p., b.i.d.) or vehicle (water) was administered beginning the day before surgery. Rat cardiac allograft survival to cessation of heart beat, apoptosis of cardiac myocytes, degree of myocardial inflammation, and inducible nitric oxide synthase (iNOS) messenger RNA (mRNA), protein, and enzyme activity were studied at days 1, 3, 5, and 7 after transplantation. Allograft survival was increased significantly by 26% from 7.5 +/- 0.8 days in vehicle-treated rats (n = 6) to 9.5 +/- 1.2 days in CNI-1493-treated rats (n = 8, p < 0.05). Apoptotic cells per mm2 myocardium decreased from 2.25 +/- 1.25 to 0.84 +/- 0.49 at day 3 and 31.2 +/- 2.9 to 17.6 +/- 5.43 at day 5 after transplantation with CNI-1493 treatment (p < 0.05). The number of apoptotic myocytes and loss of cardiac muscle cells also decreased significantly at day 5 in the treated animals (p < 0.05). The reduction of myocyte loss at day 5 coincided with a significant decrease of the inflammatory response and reduced macrophage influx (p < 0.05). Myocardial iNOS mRNA, protein, and enzyme levels increased during the course of allograft rejection, and CNI-1493 did not significantly reduce iNOS expression in the rejecting rat allograft. CNI-1493 prolongs allograft survival and reduces myocyte loss, apoptosis, and inflammation during rat cardiac allograft rejection. These effects of CNI-1493 appear to be unrelated to altered NO synthesis but may be related to effects of the drug to inhibit macrophage synthesis of cytokines.

Animals↗
PubMed1998

Effects of carbamazepine on plasma extravasation and bronchoconstriction induced by substance P, capsaicin, acetaldehyde and histamine in guinea-pig lower airways.

We evaluated the in vivo effects of the pretreatment with carbamazepine (CBZ) at different doses (10, 20 and 40 mg/kg p.o.) on the Evans-blue extravasation and on bronchoconstriction induced by different substances in guinea-pig tracheal tissue. The drug dose-dependently inhibited the extravasation induced by substance P (SP), capsaicin and acetaldehyde, but not that induced by histamine. At the highest dose (40 mg/kg) CBZ inhibited the bronchoconstriction induced by SP, capsaicin and acetaldehyde, but not that produced by histamine administration. The in vitro study with guinea-pig tracheal preparation indicates that the drug does not interfere with the binding of SP to its receptors. Our results suggest that CBZ exerts a protective activity against the pro-inflammatory action of SP.

Acetaldehyde↗
PubMed1998

Heart involvement in systemic sclerosis: an ultrasonic tissue characterisation study.

BACKGROUND: Clinicoepidemiological findings indicate that symptomatic heart involvement in patients with systemic sclerosis (SSc) predicts a very poor prognosis. At necropsy studies, SSc heart involvement without significant coronary lesions is characterised by patchy myocyte necrosis and contraction band necrosis with collagen replacement leading to myocardial fibrosis. There is a discrepancy between the frequency of clinically evident myocardial disease (25%) and autoptical myocardial fibrosis (81%). OBJECTIVE: The aim of this study was to detect preclinical myocardial alterations in SSc patients by ultrasonic videodensitometric analysis. METHODS: Thirty five SSc patients (three male, aged 48.6 (11) SD years, range 22-65) with normal ventricular function and 25 age and sex matched healthy controls were studied. All patients had a negative maximal exercise stress; in all cases arterial hypertension, renal involvement, and diabetes were excluded. Echocardiographic images were digitised by a real time videodigitiser (Tomtec Imaging Systems). Quantitative texture analysis was performed on data from the septum and the posterior wall, obtaining mean gray level histogram (MGL) at both end-diastole (d) and end-systole (s). The cyclic variation index (CVI), was calculated according to the formula ((MGLd-MGLs)/MGLd) x 100. Left ventricular mass (LVM), body surface corrected, was calculated according to Penn convention. RESULTS: Comparable systolic and diastolic blood pressure, LVM, diastolic and systolic function were recorded in both SSc patients and controls. In contrast, in SSc patients the CVI, which is the expression of the intrinsic myocardial structural function, was significantly lower than in controls (septum: -18 (28)% v 35 (10)%, p < 0.0001; and posterior wall: -13 (32)% v 50 (20)%, p < 0.0001). Changes in cyclic echo amplitude, probably related to myocardial fibrosis, were detected in the large majority of SSc patients (88%). CONCLUSIONS: Ultrasonic videodensitometric analysis represents a non-invasive, feasible method that can detect early myocardial changes in SSc patients, which could be related to both fibrosis and microcirculatory abnormalities. Their potential evolution towards ventricular dysfunction and their link with cardiac sudden death, because of severe conduction system or rhythm disturbances, should be further investigated.

Adult↗
PubMed1998

Cytokines and cognitive function in mice

A bidirectional flow of informations exists between the central nervous system and the immune system. Cytokines play a crucial role in this communication and exert several neuromodulatory actions. This short review considers some data concerning the effects of several cytokines, interleukin (IL)-1, IL-2, IL-6 and granulocyte-macrophage colony-stimulating factor on scopolamine-induced amnesia for a passive avoidance response, and on hippocampal neurotransmitter amino acid levels in mice. We interpret these behavioral and biochemical observations to indicate that the cytokine-to-brain communication can result in alterations in brain functions.

Journal Article↗
PubMed1998

[Rectal endometriosis. Apropos of a clinical case].

Regarding a case of rectal endometriosis, presenting with cyclic menstrual rectal bleeding, the authors discuss the clinical and treatment aspects of such a rare pathology. History was sufficient to indicate the diagnosis which was confirmed by the histological examination of the excised rectal tract. These observations underline the diagnostic difficulty; the surgical approach is the treatment of choice when medical treatment gives no success.

Adult↗
PubMed1998

In vitro effect of estradiol, progesterone, testosterone, and of combined estradiol/progestins on low density lipoprotein (LDL) oxidation in postmenopausal women.

OBJECTIVE: One of the mechanisms currently proposed to explain the cardioprotective effect of hormone replacement therapy (HRT) is the antioxidative property of estrogens. Considering that HRT involves the administration of an estrogen, usually combined with a progestin and sometimes with an androgen, we investigated the following in vitro: (1) the effect of estradiol, progesterone, and testosterone on the oxidation of low density lipoprotein; (2) the possible pro-oxidative effect of progesterone and testosterone on native low density lipoprotein; and (3) the possible modification of the antioxidant effect of estradiol on low density lipoprotein induced by progestins. DESIGN: Low density lipoprotein was isolated from blood samples obtained from 20 untreated postmenopausal women and divided in multiple aliquots, each containing 0.5 mg LDL protein. In Protocol 1 (n = 10) different doses of estradiol, progesterone, and testosterone ranging from 0 to 26 micrograms/ml were tested inducing oxidation with 15 microM copper sulfate. In Protocol 2 (n = 6) we studied the rate of oxidation of low density lipoprotein incubated with progesterone or testosterone without any oxidative induction. In Protocol 3 (n = 10) we studied the concomitant effect of 15 microM estradiol with four separate progestins (progesterone, medroxyprogesterone acetate, norethindrone, and norgestrel) in different doses (0, 5, 15, and 50 microM). After incubation for 4 h at 37 degrees C, malonaldehyde was measured as a marker of low density lipoprotein oxidation. The results were expressed in mean +/- SD. RESULTS: Protocol 1: Estradiol induced a dose-dependent decrease in malonaldehyde generation, from a baseline of 61.8 +/- 30.2 nmol/mg protein to 11.6 +/- 7.1 nmol/mg protein at the highest dose of estradiol tested (p < 0.0001). Progesterone or testosterone did not modify malonaldehyde generation. Protocol 2: Progesterone and testosterone did not show pro-oxidative action. Protocol 3: Estradiol 15 microM alone induced a 35% decrease in malonaldehyde generation, from a baseline of 75.4 +/- 25.4 to 49.3 +/- 18.8 nmol/mg protein (p < 0.0001). Norgestrel and norethindrone did not modify the antioxidant effect of estradiol (p > 0.05). Progesterone and medroxyprogesterone acetate induced a further reduction of malonaldehyde concentration to 37.2 +/- 20.8 and 38.6 +/- 18.2 nmol/mg protein, only at the highest dose tested (p < 0.02 and p < 0.01, respectively). CONCLUSIONS: Our results demonstrate that, in contrast with the potent antioxidant effect of estradiol, progesterone and testosterone did not show any pro- or antioxidant effect on low density lipoprotein in vitro. Furthermore, progestins did not counteract the antioxidant effect of estradiol in vitro.

Copper Sulfate↗
PubMed1998

[Comparison of the antioxidant effect of estriol and estradiol on low density lipoproteins in post-menopausal women].

BACKGROUND: Estradiol (E2) has a potent antioxidant effect on low density lipoproteins (LDL) in vitro and in vivo, which could be important in explaining the cardioprotective effect of hormone replacement therapy (HRT) in post menopausal women. Estriol (E3), on the other hand, is a weak estrogen with low metabolic effects on different tissues, and at present no cardioprotective effect has been attributed to this steroid. AIM: To study the antioxidant effect of E3 on LDL and to compare it with the potent antioxidant action exhibited by E2. SUBJECTS AND METHODS: After LDL was isolated by ultra centrifugation from plasma of 12 healthy untreated post menopausal women, it was divided into aliquots containing 0.5 mg of LDL protein. Estriol and E2 in doses of 0, 1, 5, 15 and 50 microM were incubated with different aliquots of LDL. CuSO4 15 microM was added to each aliquot to induce an oxidative stress. The aliquots were then incubated during 4 hours at 37 degrees C. Malonaldehyde (MDA) was measured as a marker of LDL oxidation, and expressed as nM/mg protein. RESULTS: (mean +/- SD): Estriol induced a dose-dependent decrease in MDA concentration (baseline 62.8 +/- 21.7; 1 microM: 61.5 +/- 23.0; 5 microM: 52.9 +/- 20.3; 15 microM 43.5 +/- 20.1 and 50 microM: 31.0 +/- 17.6 nM/mg protein; F = 92.4; p < 0.0001), reaching a mean decrease of 50.7% at the highest dose tested. Estradiol has a similar dose-dependent decrease in MDA concentration (F = 60.2; p < 0.0001), revealing a more potent effect than E3 (p < 0.05), with a mean decrease of 67.4% at the highest dose tested. CONCLUSIONS: Our results demonstrate that estriol shows an important antioxidant action of LDL in vitro, although its effect is less potent than estradiol. These results raise the possibility that estriol could have a cardioprotective effect in post menopausal women, possibility that has not been yet demonstrated.

Antioxidants↗
PubMed1998

[Laparoscopic and thoracoscopic reintervention after mini-invasive surgery in emergencies].

One-hundred-eighty patients underwent emergency minimally invasive procedures (laparo and thoracoscopy) in the last two years. In twelve postoperative drawbacks another surgical procedure was performed. Laparoscopic or thoracoscopic exploration was undertaken in 8 cases while open surgery was done in 4. Complications and surgical overtiming rate was higher after endoscopic than open surgery. This approach allows us to correct very few and selected disease when a skilled surgical team is available especially during reoperations.

Emergencies↗
PubMed1998

[Correction of hypospadias].

A thorough evaluation of both urethral and penile malformation are mandatory for the choice of the best surgical treatment of patients with hypospadias. The site and the size of the urethral meatus, the presence of a chordee and of a velamentous distal urethra must be carefully assessed. In distal (glandular and coronal) hypospadias, the meatal advancement with glanduloplasty is the treatment of choice. In proximal hypospadias with chordee, the transverse preputial island flap according to the Duckett's technique allows a one-stage hypospadias repair. The awareness of the possible psychologic impact of genital malformations in childhood recommends an early correction of hypospadias, if possible during the first year of life.

Humans↗
PubMed1997

Formalin injection in the tail facilitates hindpaw withdrawal reflexes induced by thermal stimulation in the rat: effect of paracetamol.

With the aim to develop a simple behavioural method for the study of hyperalgesic processes and for the evaluation of anti-hyperalgesic properties of analgesic drugs, the effect of the tail injection of formalin (10% formaldehyde intradermally) on hindpaw nociceptive thresholds to thermal stimulation was evaluated in the rat. The formalin injection in the tail induced a significant reduction of plantar test latencies. The pretreatment with the competitive N-methyl-D-aspartate (NMDA) receptor antagonist CGP 37849 (2.0 mg/kg) completely blocked the hyperalgesic action of the formalin. The analgesic drug paracetamol (25 mg/kg) was able to prevent hyperalgesia. However, this drug was unable to block hyperalgesia when already established. Our results suggest that this method could be used for the evaluation of analgesic drugs in an experimental setting representative of clinical pain.

2-Amino-5-phosphonovalerate↗
PubMed1997

GM-CSF affects hypothalamic neurotransmitter levels in mice: involvement of interleukin-1.

We studied the effects of granulocyte-macrophage colony stimulating factor (GM-CSF) on the brain levels of several neurotransmitters in mice. Administration of GM-CSF (5.0 and 10 microg, i.p.) significantly reduced the hypothalamic levels of glutamine, glutamic acid, GABA and aspartic acid. GM-CSF (5.0 microg, i.p.) also induced a significant reduction of norepinephrine and serotonin levels in the hypothalamus, without affecting dopamine levels. The hippocampal levels of neurotransmitters were not modified by GM-CSF administration. The peripheral administration of a specific interleukin-1 receptor antagonist (IL-1ra, 50 microg, i.p.) blocked the effects of GM-CSF. These results confirm our previous behavioural data suggesting that GM-CSF is able to exert neuromodulatory actions.

Animals↗
PubMed1997

Role of the prohormone convertase PC2 in the processing of proglucagon to glucagon.

Proglucagon is alternatively processed to glucagon in pancreatic alpha-cells, or to glucagon-like peptide-1 in intestinal L cells. Here, the specificity of PC2, the major prohormone convertase of alpha-cells, was examined both in vivo and in vitro. Adenovirus-mediated co-expression of proglucagon and PC2 in GH4C1 cells resulted in a pattern of processing products very similar to that observed in alpha-cells. Oxyntomodulin, an intermediate in the processing of proglucagon, was quantitatively converted to glucagon in vitro by purified recombinant PC2, in combination with carboxypeptidase E. It is concluded that PC2 is able to act alone in the pancreatic pathway of proglucagon processing.

Animals↗
PubMed1997

Molecular bases of hexokinase deficiency.

Hexokinase (ATP: D-hexose 6-phosphotransferase, EC 2.7.1.1; HK) deficiency is a rare disease where the predominant clinical effect is nonspherocytic hemolytic anemia. We have previously shown that the only patient for which hexokinase deficiency has been so far investigated at molecular level is a double heterozygote carrying a T1667 --> C substitution on one HK type I allele and a 96 bp deletion (concerning nucleotides 577 to 672 in the HK cDNA sequence) in the other allele. To investigate whether these mutations found in the patient with the hexokinase variant referred to as 'HK-Melzo' could be associated with hexokinase deficiency, we have expressed in E. coli the wild-type human hexokinase type I and two different mutants carrying the T --> C nucleotide substitution at position 1667 and the nt 577-672 deletion, respectively. Wild-type human recombinant hexokinase is expressed in bacterial cells as a soluble catalytically active enzyme that, upon purification to homogeneity, exhibited the same kinetic properties of human placenta hexokinase type I. Both mutant hexokinases were also expressed as soluble recombinant proteins under the same conditions, but they showed an impaired catalytic activity with respect to the wild-type enzyme. In particular, the T1667 --> C substitution, causing the amino acid change from Leu529 to Ser, is responsible for the complete loss of the hexokinase catalytic activity, while the 96 bp deletion causes a drastic reduction of the hexokinase activity. Taken together, both mutations explain the hexokinase deficiency found in the patient with the 'HK-Melzo' variant.

Amino Acid Sequence↗