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Biomedical subjects

A Rossi

Publications and source records attributed to A Rossi.

At least 235 records · Page 13Linked to original sources
PubMed1999

Regulation of the platelet serotonin transporter by protein kinase C in the young and elderly.

BACKGROUND: Some data show that different factors may influence the serotonin (5-HT) uptake rate. Our study aimed at evaluating the possible role of a protein kinase C (PKC) activator, i.e., 4-beta-12-tetradecanoylphorbol-13-acetate (beta-TPA) on the platelet 5-HT uptake of young and elderly subjects, through the measurement of the 5-HT uptake itself and 3H-paroxetine ([3H]PAR) binding sites, which correspond to the transporter protein. METHODS: Human platelets and 5-HT uptake were evaluated according to the method of Arora and Meltzer, while [3H]PAR binding was performed following the Marazziti et al method. RESULTS: The results showed that beta-TPA reduced significantly the maximal velocity (Vmax) of 5-HT uptake, with no change in the Michaelis constant or in [3H]PAR binding parameters, in platelets of both young and elderly subjects. Although this last group of subjects had a significantly lower Vmax than the other, the degree of inhibition was almost the same (75%) in both. CONCLUSIONS: These findings indicate that PKC decreases the 5-HT uptake rate by modifying the phosphorylation state of the transporter and with no change in the number of [3H]PAR binding sites. The responsiveness of this pathway is identical in both young and elderly subjects.

Adult↗
PubMed1999

Identification and linkage mapping of the phsA gene of Aspergillus nidulans, where mutation affects growth and pigmentation of colonies in a temperature- and pH-dependent way.

We report the isolation and characterization of a mutant strain of the mold Aspergillus nidulans showing an altered response to environmental pH, including a reduction in its pH range for growth and the production of a melanin-like pigment at alkaline pH. We also show that the mutant strain is not detergent-sensitive and that its acid sensitivity is osmotically remediable with 0.5 M NaCl or 1.0 M sorbitol. Furthermore, the mutant phenotype is temperature-remediable with respect to pigmentation, extent of conidiation and growth diameter, with the restoration of a wild-type phenotype to the mutant strain being observed at 28 degrees C. On the other hand, the severity of the mutant phenotype is increased at 40 degrees C. Genetic analysis shows that this pH- and temperature-sensitive mutation, named phsA1, is located on the right arm of linkage group I of A. nidulans, between pabaA and yA, and that mutation phsA1 is recessive.

Aspergillus nidulans↗
PubMed1999

Presynaptic excitability changes of group Ia fibres to muscle nociceptive stimulation in humans.

Tonic muscle nociceptive discharge evoked chemically from the foot extensor digitorum brevis muscle in man produces a depression of Ia excitation and Ib inhibition of the soleus (Sol) motoneurones (Mns). The possibility that both these changes partly result from presynaptic inhibition of Ia fibres projecting to Sol Mns and to interneurones mediating group I non-reciprocal inhibition is tested. Convergence of Ia fibres on these interneurones was deduced from evidence that reducing the excitatory effect of the extensor Ia fibres (by potentiation of their presynaptic inhibition) resulted in Ib disinhibition. Nociceptive-induced potentiation of Ia presynaptic inhibition was deduced from the following congruent results obtained by two independent methods: (1) depression of heteronymous Ia monosynaptic facilitation of the quadriceps muscle to Sol Mns; (2) potentiation of presynaptic inhibition of Sol Ia fibres evoked by mechanical activation of the tibialis anterior primary spindle afferents. It is concluded that nociceptive volleys arising from dorsal foot muscles facilitate the activity of interneurones intercalated in pathways responsible for presynaptic inhibition of Sol Ia fibres. It is also proposed that the same Ia presynaptic inhibition depresses the excitability of interneurones mediating group I non-reciprocal inhibition, thus resulting in Ib disinhibition of Sol Mns.

Adult↗
PubMed1999

On the effect of chemically activated fine muscle afferents on interneurones mediating group I non-reciprocal inhibition of extensor ankle and knee muscles in humans.

In a previous paper it was shown that muscle nociceptive discharge depressed the activity of interneurones mediating group I non-reciprocal inhibition (or Ib interneurones) in humans [A. Rossi, B. Decchi, Changes in Ib heteronymous inhibition to soleus motoneurons during cutaneous and muscle nociceptive stimulation in humans, Brain Res. 774 (1997) 55-61.]. However, since nociceptive discharge depressed the size of the soleus H-reflex (by which Ib inhibition was tested) the question arises as to whether modification of motoneurone membrane conductance per se could depress the size of Ib inhibitory post-synaptic potentials. The results of the present study suggest that the contribution of motoneurone hyperpolarization to Ib disinhibition is negligible and that muscle nociceptive discharge actually depresses the activity of these pathways.

Ankle↗
PubMed1999

Effect of inspiratory flow waveform on work on endotracheal tubes: a model analysis.

OBJECTIVE: This model analysis aimed to predict the impact of different inspiratory flow wave-forms, i. e., constant, sinusoidal, and two linearly decreasing flows, on the resistive work (Wres) performed on endotracheal tubes. DESIGN: Model analysis. RESULTS: Model analysis predicts that: (i) minimal Wres is obtained with the constant flow; (ii) for any given tidal volume/inspiratory duration (V(T)/T(I), mean inspiratory flow), Wres increases with decreasing tube size; (iii) for any given inspiratory flow waveform, Wres increases with increasing V(T)/T(I), being lowest with constant flow. CONCLUSIONS: These findings have major clinical implications: at any given ventilator setting, not only the size of the endotracheal tube but also the inspiratory flow waveform must be taken into account to interpret the values of Wres and hence of the total work of breathing.

Airway Resistance↗
PubMed1999

Effects of open heart surgery on respiratory mechanics.

OBJECTIVE: To investigate the changes in respiratory mechanics in patients undergoing cardiac surgery before and after the operation. DESIGN: Prospective physiological study. SETTING: Operating theatre of the Institute of Cardiac Surgery, Verona, Italy. PATIENTS: 8 patients needing heart surgery because of a coronary bypass or mitral valve replacement. MEASUREMENTS AND RESULTS: We measured respiratory mechanics before and immediately after the surgical procedure with two techniques: (1) the rapid airway occlusion technique during constant flow inflation at different lung volumes, and (2) the negative expiratory pressure (NEP) technique. We found that static and dynamic elastance (15.3 +/- 3.3 and 19.0 +/- 5.5 cmH(2)O/l, respectively) and respiratory resistance, both airway and total flow resistance (5.8 +/- 2.5 and 10.3 +/- 4 cmH(2)O. l(-1). s, respectively) before surgery were slightly higher than in normal anaesthetised subjects. In all patients, the static inflation V-P curves fitted the power function and exhibited a slight upward concavity towards the volume axis (a = 16.9 +/- 3.5, b = 0.74 +/- 0. 07), indicating that elastance decreased with inflating volume. Whereas elastance increased by 30 %, neither intrinsic positive end-expiratory pressure, which was small, averaging 1.5 +/- 1.2 cmH(2)O, nor flow resistance changed after surgery. With the NEP technique, four patients exhibited expiratory flow limitation during the tidal expiration, for about 67 % of the exhaled volume, without changes after surgery. Arterial carbon dioxide tension (32 +/- 4 mm Hg) and pH (7.46 +/- 0.07) did not change, whereas arterial oxygen tension (PaO(2)) (242 +/- 34 mm Hg) decreased significantly by about 70 mm Hg, on average, with a constant fractional inspired oxygen (0. 50). CONCLUSIONS: This study shows that (1) respiratory mechanics can be abnormal in patients undergoing cardiac surgery, including expiratory flow limitation; (2) elastance increases and PaO(2) decreases after surgery; (3) simple, noninvasive techniques are available to measure respiratory mechanics in the operating theatre.

Aged↗
PubMed1999

Intracranial contrast-enhancing masses in infants with capillary haemangioma of the head and neck: intracranial capillary haemangioma?

Contrast-enhancing intracranial masses are rarely found in infants with extracranial capillary haemangiomas (CH). We aimed to assess their nature and progression in three patients undergoing CT and/or MRI. The changes in size of both extra- and intracranial lesions were recorded. In a fourth case, a single examination was obtained. All patients harboured one or two enhancing intracranial nodular, meningeal-based lesions. Diffuse leptomeningeal enhancement of the cerebellar surface was also seen in one, which disappeared at follow-up. In all but one of the cases, the intracranial lesions were on the same side as the extracranial CH. These lesions and the extracranial CH demonstrated parallel changes in size (suggesting that both represent CH) during follow-up of 1-2 years: the size of intracranial lesions and the extracranial CH decreased in two cases, whereas it was unchanged in the third. One patient had a persistent trigeminal artery, while another had cerebellar atrophy with high signal in the cortex on T2-weighted images. In some cases, extracranial CH are part of PHACE syndrome; the association with intracranial CH might represent a peculiar phenotype of this rare vascular phakomatosis. As extracranial CH are known to regress spontaneously in the majority of cases, a conservative approach is recommended also for presumed intracranial CH; surgery should be avoided unless follow-up studies demonstrate growth.

Female↗
PubMed1999

Elevated beta-N-acetylhexosaminidase activity in focal dystonia fibroblasts.

Specific activities of beta-D-hexosaminidase, alpha-D-mannosidase, beta-D-galactosidase and beta-D-glucuronidase were determined in fibroblasts of patients with writer's cramp and torticollis. These diseases show degenerative neurological disorders similar to those observed in lysosomal diseases. Hexosaminidase specific activities, determined using 4-methylumbelliferyl-beta-N-acetylglucopyranoside and 4-methylumbelliferyl-beta-N-acetylglucopyranoside-6-sulphate as substrates, were significantly higher in the fibroblasts of patients than in controls. No significant differences were observed in the specific activities of the other lysosomal enzymes. The increased hexosaminidase specific activities in torticollis and writer's cramp may be additional markers for these diseases.

Adult↗
PubMed1999

Decreased platelet 3H-paroxetine binding in untreated panic disorder patients.

Different findings support the involvement of the serotonin (5-HT) system in panic disorder. The presence of the 5-HT transporter in blood platelets similar to that in presynaptic serotonergic neurons, permits the investigation of this structure in periphery. We therefore evaluated the binding of 3H-paroxetine, a selective 5-HT reuptake inhibitor which is considered the ligand of choice for labelling the 5-HT transporter, in platelets of 20 drug-free patients with panic disorder. The same measurement was repeated after one year's treatment with different drugs. The results showed patients to have a lower number of 3H-paroxetine sites than a group of age- and sex-matched controls, thus suggesting the involvement of the 5-HT transporter in panic disorder. This abnormality reverted after one year of treatment with specific drugs that provoked the symptom remission in all cases, which would suggest a link with the clinical improvement.

Adolescent↗
PubMed1999

Left atrial filling volume can be used to reliably estimate the regurgitant volume in mitral regurgitation.

OBJECTIVES: The objective was to analyze the accuracy and diagnostic value of the estimated regurgitant volume of mitral regurgitation using 1) left atrial volume variation during ventricular systole (left atrial filling volume) and 2) the percent of systolic pulmonary vein velocity integral compared with its total. BACKGROUND: Left atrial filling volume (LAfill), which represents the atrial volume variation during ventricular systole, has been used for the assessment of mitral regurgitation severity. A good correlation with invasive semiquantitative evaluation was found, but with an unacceptable overlapping among grades. The reason could be the absence of information concerning the contribution of blood entering into the left atrium from the pulmonary veins. METHODS: Doppler regurgitant volume (Dpl-RVol) (mitral stroke volume - aortic stroke volume) was measured in 30 patients with varying degrees and etiological causes of mitral regurgitation. In each patient atrial volumes were measured from the apical view, using the biplane area-length method. The systolic time-velocity integral of pulmonary vein flow was expressed as a percentage of the total (systolic-diastolic) time-velocity integral (PVs%). These parameters were used in this group of patients to obtain an equation whose reliability in estimating Dpl-RVol was tested in a second group of patients. RESULTS: In the initial study group, with linear regression analysis the following parameters correlated with Dpl-RVol: end-systolic left atrial volume (R2=0.37, p=0.0004); LAfill (R2=0.45, p < 0.0001); PVs% (R2=0.56, p < 0.0001). In multiple regression analysis the combination of LAfill and the percent of the systolic pulmonary vein velocity integral (PVs%) provided a more accurate estimate of regurgitant volume (R2=0.88; SEE 10.6; p < 0.0001; Dpl-RV=6.18 + (1.01 x LAfill) - (0.783 x PVs%). The equation was subsequently tested in 54 additional patients with mitral regurgitation with a mean Dpl-RVol 27+/-37 ml. Estimated regurgitant volume and Dpl-RVol correlated well with each other (R2=0.90; SEE 12.1; p < 0.0001). In the test population, the equation was 100% sensitive and 98% specific in detecting a regurgitant volume higher than 55 ml. CONCLUSIONS: Left atrial filling volume and pulmonary vein flow give a reliable estimate of regurgitant volume in mitral regurgitation.

Adult↗
PubMed1999

Progression of mitral regurgitation: a prospective Doppler echocardiographic study.

OBJECTIVES: This study was performed to define the rates and determinants of progression of organic mitral regurgitation (MR). BACKGROUND: Severe MR has major clinical consequences, but the rates and determinants of progression of the degree of regurgitation are unknown. Quantitative Doppler echocardiographic methods allow the quantitation of regurgitant volume (RVol), regurgitant fraction (RF) and effective regurgitant orifice (ERO) to define progression of MR. METHODS: In a prospective study of MR progression, 74 patients had two quantitative Doppler echocardiographic examinations of MR (with at least two methods) 561 +/- 423 days apart without an intervening event. RESULTS: Progression of MR was observed, with increase in RVol (77 +/- 46 ml vs. 65 +/- 40 ml, p < 0.0001), RF (47 +/- 16% vs. 43% +/- 15%, p < 0.0001), and ERO (50 +/- 35 mm2 vs. 41 +/- 28 mm2, p < 0.0001). Annual rates (95% confidence interval) were, respectively, 7.4 ml/year (5.1, 9.7), 2.9%/year (1.9, 3.9) and 5.9 mm2/year (3.9, 7.8). However, wide individual variation was observed, and regression and progression of RVol >8 ml was found in 11% and 51%, respectively. In multivariate analysis, independent predictors of progression of RVol were progression of the lesions, particularly a new flail leaflet (p = 0.0003), and progression of mitral annulus diameter (p = 0.0001). Regression of MR was associated with marked changes in afterload, particularly decreased blood pressure (p = 0.008). No significant effect of treatment was detected. CONCLUSIONS: Organic MR tends to progress over time with increase in volume overload (RVol) due to increase in ERO. Progression of MR is variable and determined by progression of lesions or mitral annulus size. These data should help plan follow up of patients with organic MR and future intervention trials.

Adult↗
PubMed1999

Distribution and characterization of [3H]mesulergine binding in human brain postmortem.

Much interest is currently being directed towards serotonin (5-HT) receptors of type 2C (5-HT2C) because of their possible involvement in the control of different activities, such as the composition of the cerebrospinal fluid, locomotion, feeding, neuronal excitability and anxiety. The limited information regarding their distribution in the human brain prompted us to investigate, and to characterize the binding of [3H]mesulergine, a HT2C antagonist, in autopsy samples from 24 subjects. The results showed that the [3H]mesulergine binding represented 95% of the total binding and equilibrium saturation binding experiments resulted in a single straight line, consistent with the presence of one site only. The area with the highest density of [3H]mesulergine binding was the choroid plexus, followed at a significantly lower level by the hippocampus, substantia nigra, basal ganglia, amygdala, hypothalamus and prefrontal cortex. The pharmacological profile of the [3H]mesulergine binding was consistent with that of 5-HT2C receptors, since the most effective displacers were ritanserin, mesulergine and mianserine, followed by clozapine, ketanserine and m-CPP, while other compounds had a negligible or no effect. These findings, showing a wide distribution of [3H]mesulergine binding sites in the human brain, could provide anatomical bases for the different functions attributable to 5-HT2C receptors in humans.

Adult↗
PubMed1999

Calcium chloride minimizes the hemodynamic effects of propofol in patients undergoing coronary artery bypass grafting.

OBJECTIVE: To assess the hemodynamic effects of propofol and the counteracting effect of calcium chloride (CaCl2) in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Prospective, randomized study. SETTING: University hospital, department of cardiac surgery. PARTICIPANTS: Fifty-eight patients undergoing elective CABG, divided into group A (n = 29) and group B (n = 29). INTERVENTIONS: Anesthesia was induced with a combination of fentanyl, 7 microg/kg; pancuronium, 0.1 mg/kg; and propofol, 1.5 mg/kg, administered over 60 seconds. A blinded investigator administered saline in group A patients and 10 mg/kg of CaCl2 in group B patients at the same speed and same time as propofol administration through another lumen of the central venous catheter. MEASUREMENTS AND MAIN RESULTS: Hemodynamic data were obtained at baseline (T0), 2 minutes after anesthesia induction (T1), and 2 minutes after tracheal intubation (T2). Heart rate decreased significantly in group A patients (86.2+/-11.3 beats/min at T0 and 72.8+/-7.5 beats/min at T2; p < 0.001). Mean arterial pressure decreased significantly in patients in both groups (group A, 108.0+/-12.0 mmHg at T0; 74.6+/-14.6mmHg at T2;p < 0.001 and group B, 106.0+/-10.2 mmHg at T0; 90.4+/-10.0 mmHg at T2; p < 0.05). Stroke volume index, cardiac index, and cardiac output decreased in group A patients (39.4+/-4.1 mL/beat/m2 at T0 and 28.8+/-5.2 mL/beat/m2 at T2; p < 0.05; 3.4+/-0.6 L/min/m2 at T0 and 1.9+/-0.3 L/min/m2 at T2; p < 0.001; 5.9+/-0.9 L/min at T0 and 3.4+/-0.4 L/min at T2; p < 0.001, respectively), whereas in group B patients, changes were negligible (38.1+/-7.0 mL/beat/m2 at T0 v 35.7+/-6.6 mL/beat/m2 at T2; (NS) 3.3+/-0.5 L/min/m2 at T0 v 2.7+/-0.3 L/min/m2 at T2; (NS) 5.7+/-0.9 L/min at T0 v 4.7+/-0.5 L/min at T2; (NS), respectively). CONCLUSION: Simultaneous administration of CaCl2 during the induction of anesthesia minimizes the potential negative effect of propofol on cardiac function in cardiac patients.

Anesthetics, Intravenous↗
PubMed1999

Alteration of the platelet serotonin transporter in romantic love.

BACKGROUND: The evolutionary consequences of love are so important that there must be some long-established biological process regulating it. Recent findings suggest that the serotonin (5-HT) transporter might be linked to both neuroticism and sexual behaviour as well as to obsessive-compulsive disorder (OCD). The similarities between an overvalued idea, such as that typical of subjects in the early phase of a love relationship, and obsession, prompted us to explore the possibility that the two conditions might share alterations at the level of the 5-HT transporter. METHODS: Twenty subjects who had recently (within the previous 6 months) fallen in love, 20 unmedicated OCD patients and 20 normal controls, were included in the study. The 5-HT transporter was evaluated with the specific binding of 3H-paroxetine (3H-Par) to platelet membranes. RESULTS: The results showed that the density of 3H-Par binding sites was significantly lower in subjects who had recently fallen in love and in OCD patients than in controls. DISCUSSION: The main finding of the present study is that subjects who were in the early romantic phase of a love relationship were not different from OCD patients in terms of the density of the platelet 5-HT transporter, which proved to be significantly lower than in the normal controls. This would suggest common neurochemical changes involving the 5-HT system, linked to psychological dimensions shared by the two conditions, perhaps at an ideational level.

Adult↗
PubMed1999

Clinical outcome after autologous transplantation in non-Hodgkin's lymphoma patients with high international prognostic index (IPI).

BACKGROUND: Dose intensification and autologous stem cell transplantation as front-line therapy in non-Hodgkin's lymphoma patients (NHL) is a matter for debate, although preliminary data suggest a role for it in patients at high risk of resistance or relapse according to the international prognostic index (IPI). PURPOSE AND STUDY DESIGN: To compare retrospectively the clinical outcome of two cohorts of NHL patients with high-risk IPI treated with MACOP-B for 12 weeks (38 patients) or high-dose chemotherapy (44 patients) including eight weeks of MACOP-B, one or two intensification cycles with mitoxanthrone, dexamethasone, high-dose ara-C and finally BEAM chemotherapy with autologous hemopoietic progenitor cell transplantation. RESULTS: The actuarial estimate of event (progression, relapse or death)-free survival (EFS) at three years was better (58% vs. 41%, P = 0.08) for patients treated with intensive regimen even though the overall survival did not show a statistically significant difference (63% vs. 50%, P = 0.27). Multivariate analysis showed that the high-dose chemotherapy program was the only independent variable correlating with a reduction in the event rate. CONCLUSION: Early autologous stem-cell transplantation might improve the clinical outcome of high-risk patients according to IPI.

Adolescent↗
PubMed1999

Stage-modified international prognostic index effectively predicts clinical outcome of localized primary gastric diffuse large B-cell lymphoma. International Extranodal Lymphoma Study Group (IELSG)

BACKGROUND: The definition of prognostic parameters in early stages of gastric lymphoma is still controversial. The aim of this retrospective analysis was to assess the value of the stage-modified international prognostic index (IPI) in predicting the outcome of a large, consecutive series of patients with PGL of diffuse large B-cell histology (DLCL). PATIENTS AND METHODS: Three hundred twelve consecutive, newly-diagnosed, patients with localized PGL (stages I-IIE according to the 'Lugano staging system for GI lymphomas') referred from April 1972 to December 1997 to eight Italian and one Swiss centers were reviewed and their outcomes updated to June 1998. One hundred three patients were treated with single-modality therapy, while two hundred four received combined-modality treatment, most of which included surgery and short-term chemotherapy. RESULTS: After a median follow-up of 66 months (range 0.6-300 months), 195 (64%) were alive in first continuous complete remission (CCR). The five-year estimates of overall survival (OS) and event-free survival (EFS) were 75% and 67%, respectively. OS and EFS varied according to IPI, from, respectively, 90% and 82% for patients with 0-1 risk factors, to 40% and 35% for patients with > or = 3 risk factors (P = 0.00001). Cox regression analysis showed that IPI was the strongest predictor of survival. CONCLUSIONS: This study shows that stage-modified IPI is an effective predictive model in patients with primary DLCL of the stomach, enabling identification of patients with significantly different outcomes.

Adolescent↗
PubMed1999

Myotonic dystrophy (Steinert disease): a morphologic and biochemical hair study.

BACKGROUND: Myotonic dystrophy is a systemic genetic disorder, with dominant transmittance. It is characterized by generalized progressive muscular abnormality. Although frontoparietal alopecia is one of the most common symptoms in myotonic dystrophy, it has not received much attention. METHODS: We examined 25 subjects from two families: 10 patients were affected by Steinert disease and 15 were not. The various morphologic and biochemical hair alterations are reported. RESULTS: All investigated subjects (affected or not) presented the same type of morphologic and biochemical hair alterations. CONCLUSIONS: These findings could be used to construct a hypothesis to explain the cause of the disease.

Adult↗