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Biomedical subjects

G Rossi

Publications and source records attributed to G Rossi.

At least 505 records · Page 28Linked to original sources
PubMed1991

Dependence of Ypt1 and Sec4 membrane attachment on Bet2.

Many small GTP-binding proteins are synthesized as soluble proteins that are post-translationally modified as a prerequisite for membrane attachment. Ypt1 and Sec4 are homologous Raslike GTP-binding proteins that have been proposed to regulate the specificity of vesicular traffic at different stages of the secretory pathway by cycling on and off membranes. Here we show that BET2, initially identified as a gene required for transport from endoplasmic reticulum to Golgi apparatus in yeast, encodes a factor that is needed for the membrane attachment of Ypt1 and Sec4. DNA sequence analysis has revealed that Bet2 is homologous to Dpr1 (Ram1), an essential component of a protein prenyltransferase that modifies Ras, enabling it to attach to membranes. We propose that Bet2 modifies Ypt1 and Sec4 in an analogous manner.

Amino Acid Sequence↗
PubMed1991

Immunologic detection of endothelial cells in human whole blood.

In this report we show that human endothelial cells (EC) can be detected in circulating blood by means of the EC-specific monoclonal antibody (MoAb) designated as CLB-HEC 19 and expressed quantitatively as number of cells per milliliter of whole blood. We first developed a method that was able to recover cultured human EC added to whole blood by Percoll density gradient centrifugation. The final recovery of the EC was 91.6% (SE = 0.65%). The EC were identified in the gradient subfractions by indirect immunofluorescence with the MoAb CLB-HEC 19. This method was then applied to the separation and characterization of EC or EC remnants from the whole arterial and venous blood taken from two groups of patients subjected to heart catheterization. Firstly, a preliminary blood screening of random samples was performed in a group of eight patients (group I) using a scoring evaluation for the presence of EC and the results were expressed as positivity index. Secondly, the complete blood screening of a group of ten patients (group II) was performed for the detection of immunofluorescent cells and the results were expressed as number of EC per milliliter of whole blood. Our results show in both group I and II a significant presence of EC in the blood after catheterization compared with their basal values. The minimal detectable concentration of EC was 0.06 cells/mL (SE = 0.057) of whole blood. We consider this technique as a suitable clinical test for the detection of EC injury in cardiovascular pathology.

Antibodies, Monoclonal↗
PubMed1991

"Desmoplastic" versus "classic" medulloblastoma: comparison of DNA content, histopathology and differentiation.

A microfluorometric analysis was performed to analyse the DNA content of 42 medulloblastomas (MBs) and to seek correlations, if any existed, between the DNA distribution and ploidy values, neoplasm types (i.e. classic vs desmoplastic), histological features of aggressiveness, and immunocytochemical features indicating glial and/or neuronal differentiation. Thirty-one cases were classified as classic and 11 cases as desmoplastic MBs. Ten of 11 desmoplastic MBs had a near-diploid main mode and the remaining 1 case had a near-tetraploid main mode. Moreover, 10 of 11 (90%) cases showed a "monomodal" DNA distribution diagram. All these cases showed a uniform histology. In contrast, classic MBs represented a heterogeneous group of neoplasms. Twenty-two cases were near-diploid, 5 cases were near-tetraploid and 3 cases were near-triploid. The histogram type distribution showed a similar heterogeneity. Twelve of 31 (39%) cases had a monomodal histogram, 12 (39%) cases had a bimodal diagram and 7 (22%) cases a complex DNA distribution. There was a statistically significant difference (P less than 0.001) in terms of prevalence of DNA monomodal histograms between classic and desmoplastic MBs. Significant correlations were not observed among classic MBs between histological features of aggressiveness, type and degree of differentiation and DNA distribution. The present study indicates that desmoplastic MBs represent a homogeneous group of neoplasms in terms of histology and DNA distribution. In contrast, classic MBs are lesions with different degrees of histologically apparent aggressiveness and a complex DNA distribution.

Adolescent↗
PubMed1991

Restoration of normal growth hormone responsiveness to GHRH in normal aged men by infusion of low amounts of theophylline.

In order to establish whether the age-related reduced growth hormone (GH) responsiveness to GH-releasing hormone (GHRH) could be improved by treatment with low amounts of theophylline, a drug mainly acting through cyclic adenosine 3', 5'-monophosphate (cAMP), and calcium-mediated mechanisms, eight adult subjects (aged 20-37) and eight elderly men (aged 64-79) were tested with GHRH (50 micrograms in an iv bolus), theophylline (1.67 mg/min for 3 h), or the combination of both drugs. The GH response to GHRH was significantly lower in the older than in the younger group (mean peaks were 4.5 and 7.5 times higher than baseline, respectively). Theophylline did not change basal GH levels in any subjects and GHRH-induced GH rise in the younger group, whereas it restored normal GH responses to GHRH in the older subjects (mean peak responses were eight times higher than baseline in both groups). These data show that in elderly subjects the mechanism underlying the GHRH-induced GH secretion may be fully activated by GHRH during treatment with low amounts of theophylline.

Adult↗
PubMed1991

Naloxone partly counteracts apomorphine side effects.

The effects of naloxone on side effects provoked by apomorphine (APO) administration in patients with parkinsonian syndrome have been studied. The group under study included eight patients with Parkinson's disease and four with parkinsonism who received 100 micrograms/kg s.c. APO acutely to test dopaminergic responsiveness. All patients were treated with 20 mg domperidone tablets t.i.d. and then for 2 consecutive days (in double blind fashion) were given a 2-hour i.v. saline infusion alone or with naloxone (8 mg) starting 30 min before APO administration. In both groups, naloxone delayed the appearance of sleepiness, and reduced the intensity of yawning, sleepiness, nausea, and vomiting as compared with saline. These findings indicate a potential usefulness of naloxone and other opioid antagonists in preventing acute APO side effects.

Apomorphine↗
PubMed1991

Cerebrospinal fluid shunting for hydrocephalus in the adult: factors related to shunt revision.

Cerebrospinal fluid shunting procedures are widely employed in the treatment of hydrocephalus and other disturbances of the dynamics of cerebrospinal fluid. In spite of its popularity, this operation frequently requires surgical revision. A retrospective analysis of a series of 356 adults who underwent the insertion of a cerebrospinal fluid shunt between January 1970 and December 1988 was performed. The incidence of revision was analyzed, and an attempt was made to identify possible causal factors. The overall incidence of surgical revisions was 28.65%; the number of revisions in the same patient ranged between one and eight. The most frequent causes of revision were distal malposition, obstruction, and infection. A statistically significant difference (P less than 0.05) was found in both the risk of revision in patients who had undergone previous operations and those who had not and in the incidence of revision before and after January 1985. Meticulous surgical technique as well as perioperative antibiotic prophylaxis appear responsible for the latter. The differences in the incidence of revision among patients treated with different types of shunts and valves, though remarkable, is not statistically significant.

Adolescent↗
PubMed1991

Limited clonal heterogeneity of antigen-specific T cells localizing in the pleural space during mycobacterial infection.

To detect possible differences in phenotype and fine specificity for mycobacterial antigens between CD4-positive T cells from peripheral blood (PB) and from inflammatory sites, we identified four patients presenting with a mycobacterial pleural exudate (PE) rich in PPD-specific lymphocytes and with a negative skin test to tuberculin purified protein derivative (PPD) and a negative proliferative response of PB lymphocytes to PPD at the same time. Several weeks after chemotherapy, these patients converted to PPD responsiveness in the periphery, and PPD-specific clones could be generated from PB at this stage. The phenotypic comparison of PE lymphocytes and concomitant PB lymphocytes obtained before treatment showed an increase of CD8 cells and a high frequency of HLA-DR-positive activated T cells in PE. The frequency of tetanus toxoid-specific and Candida albicans-specific proliferating T cells was lower than that of PPD-specific cells in PE but not in PB. PPD-specific clones were derived initially from PE and from PB once the patients had converted to PPD responsiveness. The two sets of clones from each patient were compared for proliferative response to mycobacterial antigen clusters of defined molecular weight ranges. A large number of PE-derived clones (36%) responded to a fraction of 27 to 35 kDa, whereas only one clone from PB responded to the same fraction. The purified antigen P32 (32 kDa), a soluble mycobacterial protein, stimulated PE-derived clones that were responsive to the 37- to 27-kDa fraction but did not stimulate PB-derived clones. The data demonstrate that PE- and PB-derived lymphocytes differ both in phenotype and in fine specificity, suggesting a limited clonal heterogeneity of T cells localizing at the inflammatory site in tuberculous patients without a PPD response in the periphery. Therefore T cells compartmentalized at inflammatory sites provide information that is different from that provided by T cells in the periphery.

Antigens, Bacterial↗
PubMed1991

Recovery time of the temporary threshold shift for delayed evoked otoacoustic emissions and tone bursts.

The recovery time of temporary threshold shift after 1-kHz tone bursts delayed evoked otoacoustic emissions (DEOE) after the same stimulus were studied after auditory fatigue (AF) with a pure tone (0.75 kHz, 10 min, 95 dB HL) in 20 normal-hearing subjects aged 19-23 years. Close similarities were observed in the two experimental conditions. Since DEOE are transmitted to the outer ear via structures independent of the fibers of the afferent acoustic pathway and their synapses, it may be supposed that changes in the motile activity of the outer hair cells caused by AF could be partly responsible for their production and could constitute an active intracochlear mechanism taking part in this phenomenon. It may also be supposed that the effects of this active mechanism could be superimposed on those produced by a passive intracochlear mechanism consisting of the traveling wave induced in the basilar membrane by the perilymph owing to the movements of the stapes.

Adolescent↗
PubMed1991

Inhaled furosemide prevents both the bronchoconstriction and the increase in neutrophil chemotactic activity induced by ultrasonic "fog" of distilled water in asthmatics.

Inhaled furosemide has been shown to prevent bronchoconstriction induced by inhalation of ultrasonic nebulization of distilled water (UNDW) in bronchial asthma. To evaluate whether inhaled furosemide also prevents the increase in serum neutrophil chemotactic activity (NCA) observed during UNDW bronchoconstriction, we measured NCA during UNDW challenge without (control) and immediately after inhalation of furosemide (40 mg) or placebo (saline) in 10 asthmatics responsive to UNDW, in a randomized, double-blind study. NCA was assessed by measuring the maximal distance reached by neutrophils in a filter when challenged with the subject serum in a Boyden chamber ("leading front"). UNDW inhalation produced a significant increase in NCA in each subject. Gel filtration chromatography on S400 column indicated that the NCA released were 600 to 700 kD. Saline had no effect on bronchoconstriction nor on NCA increase induced by UNDW in nine patients. Furosemide did not change baseline FEV1, but it prevented bronchoconstriction and NCA increase in nine patients. In the whole group the maximal decrease in FEV1 after UNDW was -31.1%, SEM 4.7 after saline and -7.5%, SEM 5.2 after furosemide, p less than 0.001, the maximal increase in NCA after UNDW was +52.9%, SEM 9.2 after saline and +3.8%, SEM 3.1 after furosemide, p = 0.001. These results indicate that inhaled furosemide prevents both the bronchoconstriction and the NCA increase induced by UNDW inhalation in most asthmatic patients. This finding adds support to the suggestion that furosemide acts on mast cells.

Administration, Inhalation↗
PubMed1991

Local immunotherapy by inhalation of a powder extract in asthma due to house dust mite Dermatophagoides pteronyssinus: a double-blind comparison with parenteral immunotherapy.

To verify the efficacy and the tolerability of local immunotherapy (LI) by inhalation of a powder extract of house dust mite (HDM), in comparison with parenteral immunotherapy (PI) by injection, 10 patients with asthma due to HDM were studied in a blind fashion. 5 patients (Group A) underwent LI and subcutaneous injections of placebo, 5 patients (Group B) underwent PI and inhalation of lactose for 6 months. In both groups each inhalation was preceded by premedication with disodium cromoglycate (DSCG) (40 mg). In Group A a significant decrease in symptoms score and in peak expiratory flow (PEF)-derived parameters was observed already after 3 months of treatment, and 2 patients lost the late component of the bronchial response to the challenge with HDM. No significant variation was found in bronchial responsiveness to methacholine and ultrasonically nebulized distilled water (UNDW) and in immunologic humoral and cellular parameters in peripheral blood after treatment in either group. No local important adverse reactions were observed in Group A and no systemic side effects were observed in either group. We conclude that LI is as effective as PI, but more rapid in its action, in the treatment of asthma due to HDM. Moreover, LI is locally well tolerated, providing DSCG is inhaled before each therapeutic inhalation, and does not induce systemic side effects.

Administration, Inhalation↗
PubMed1991

Role of beta 1 integrins in tumor cell adhesion to cultured human endothelial cells.

We investigated the effects of beta 1 integrins on tumor cell (TC) adhesion to unstimulated and interleukin-1 (IL-1) activated endothelial cells (EC). IL-1 treatment (20 units/ml for 6 hours) of cultured human umbilical vein EC significantly increased adhesion of seven human TC lines of different origin. A goat antiserum raised to purified alpha 5 beta 1 integrin abolished the IL-1 induced increment in adhesion of two osteosarcomas, one melanoma, one lung, and one kidney carcinoma, whereas it did not affect adhesion of two colon carcinoma cell lines. Further studies were performed on MG63 osteosarcoma cells. Adhesion of MG63 osteosarcoma cells to EC was dependent on time of EC treatment with IL-1: it was maximal at 12 hours and declined at 24 hours. alpha 5 beta 1 antiserum blocked IL-1 induced increase in MG63 adhesion at any time of EC treatment. This effect appears to be mainly directed to MG63 integrins since selective incubation of the antiserum with EC, but not with MG63, did not modify TC adhesion. Using a series of antibodies to different alpha and beta chains, we found that only monoclonal antibodies (mAb) to alpha 4, alpha 5, and beta 1 could inhibit MG63 adhesion to IL-1 activated EC, whereas alpha 2, alpha 6, and beta 3 antibodies were ineffective. Antibodies to fibronectin had very little activity on MG63 adhesion to EC matrix and did not significantly affect MG63 adhesion to control or IL-1 treated EC. Antibodies to alpha 4, alpha 5, and beta 1 were only partially effective in inhibiting MG63 adhesion to EC matrix. These data indicate that the capacity of alpha 4 beta 1 and alpha 5 beta 1 integrins to bind fibronectin contributed very little to MG63 adhesion to EC. The importance of beta 1 integrins in promoting a direct interaction between EC and MG63 was further shown by inhibition of rosette formation among these cells in suspension by the alpha 5 beta 1 antiserum. Only a VCAM-1/INCAM110 mAb, but not ELAM-1 or ICAM-1 mAbs, could inhibit MG63 adhesion to IL-1 activated EC. Overall these data indicate that at least two members of the beta 1 integrin subfamily (alpha 4 beta 1 and alpha 5 beta 1) are involved in MG63 adhesion to cytokine treated EC. This integrin function might be important at early stages of TC interaction with the vessel wall.

Antibodies, Monoclonal↗
PubMed1991

Lobar hypoplasia.

Lung tissue developmental abnormalities are seldom reported. According to the classification of Schneider (1900), which was amended by Boyden (1955), they include pulmonary agenesis, aplasia and hypoplasia. Due to the early onset of symptoms, lung agenesis and aplasia are usually detected soon after birth. Conversely, lung or lobar hypoplasia may remain clinically silent for a long time. A single case of left lower lobe hypoplasia is reported. A recurring and unrelenting septic fever was the presenting symptom, whilst the radiological picture showed a left lower lobe consolidation. On the surgical specimen gross pathology revealed a lobar hypoplasia. At a short-term follow-up (nine months) the patient shows good overall condition, being free from further complications.

Fever of Unknown Origin↗
PubMed1991

Failure of the gamma-aminobutyric acid (GABA) derivative, baclofen, to stimulate growth hormone secretion in Parkinson's disease.

In order to evaluate whether the stimulating effect of GABA on growth hormone (GH) secretion changes in patients affected by Parkinson's disease, ten male parkinsonian patients and ten age matched normal controls were tested with the GABA derivative and GABAergic agent Baclofen (10 mg in a single oral administration at 09.00 h) (experimental test). In a different occasion, normal men and parkinsonian patients were tested with a placebo (control test). Basal GH levels were similar in normal controls and parkinsonian patients and remained unmodified during the control test. Plasma GH levels rose three times within 120 min after the administration of baclofen in the normal subjects. In contrast, plasma GH concentrations remained unmodified after baclofen treatment in the parkinsonian patients. In agreement with previous reports in the literature showing alterations of GABAergic neurotransmission in the parkinsonian brain, these data show a reduced GABAergic control of GH secretion in patients with Parkinson's disease.

Aged↗