PubMed Health⌕ Search

Biomedical subjects

R Rossi

Publications and source records attributed to R Rossi.

At least 19 recordsLinked to original sources
PubMed1992

Detection of mycoplasma contamination through modulation (stimulation or inhibition) of thymidine incorporation by unstimulated mouse spleen cells.

In the present report we describe a rapid and sensitive assay for mycoplasma detection in cell cultures. The assay is based on the ability of contaminated culture supernatants to modulate [3H]TdR incorporation by unstimulated mouse splenocytes. Several mycoplasma species (Mycoplasma orale, culturable and non-culturable strains of Mycoplasma hyorhinis) inhibited [3H]TdR incorporation and permitted the detection of some contaminated cell cultures that would otherwise have escaped detection in assays measuring [3H]TdR incorporation by mitogen-stimulated splenocytes. On the other hand, several other mycoplasma species (Mycoplasma arginini, Mycoplasma hominis) strongly enhanced [3H]TdR incorporation by unstimulated splenocytes. This enhancement was optimally detectable on day 2 after initiation of the cultures. The sensitivity of the assay was determined for a mycoplasma species (culturable M. hyorhinis) that inhibited as well as for one (M. arginini) that enhanced [3H]TdR incorporation. In both cases, the sensitivity was such that 1-3 x 10(2) mycoplasma colony-forming units (CFU) could be detected.

Animals↗
PubMed1992

Monitoring of somatosensory evoked potentials during carotid endarterectomy.

Somatosensory evoked potentials (SEPs) were monitored in the course of 368 carotid endarterectomies (CEAs) carried out in 312 patients. In an initial group of 26 patients the shunt was used routinely while in a second group, involving 342 CEAs, it was applied selectively on the basis of modifications which the SEP underwent during clamping. The criterion for shunting was the progressive reduction, up to 50%, of the N20-P25 amplitude. New postoperative neurological deficits appeared in 6 patients, all of whom displayed a transitory SEP flattening. The SEPs of 2 of these returned to normal by the time they awoke and both showed a clinical deficit homolateral to the operated side. In only 2 cases did the deficit fail to regress completely and their postoperative CT scans revealed ischaemic lesions. A positive relationship emerged between SEP changes and back pressure values; nonetheless, as many as 75% of the patients with low residual back pressure values (less than 25 mmHg) tolerated the clamping. SEP monitoring appears to provide a reliable basis for selectively applying a shunt when there is a high risk of haemodynamic ischaemia during clamping.

Adult↗
PubMed1992

Tubular function and histological findings in ifosfamide-induced renal Fanconi syndrome--a report of two cases.

Two patients developed renal Fanconi syndrome (RFS) after intensive long-term chemotherapy for metastatic Ewing sarcoma and disseminated neuroblastoma. Whereas RFS was diagnosed in patient 1 before he developed osteomalacia, patient 2 experienced severe rickets and growth retardation. Renal function studies revealed slight glomerular impairment and severe tubular defects leading to increased excretion of glucose, amino acids, inorganic phosphate and low molecular weight proteins, indicating proximal tubular damage. Patient 2 additionally showed distal tubular dysfunction with acidosis and diminished concentrating capacity. Renal biopsy in patient 1 revealed marked proximal tubular defects without interstitial lymphocytic infiltration. In both patients renal damage could most likely be ascribed to previous ifosfamide (IFOS) therapy. Our patients showed no improvement in renal function after cessation of IFOS treatment, indicating a poor prognosis of once established RFS after IFOS therapy. Measurement of tubular reabsorption capacities provides exact information on the extent of tubular toxicity induced by IFOS and may be used to monitor IFOS treated patients.

Adolescent↗
PubMed1992

Hormonal and immunological pattern in a patient with acquired immunodeficiency syndrome related complex and Cushing's syndrome.

A case of Cushing's syndrome in a 24-yr-old homosexual with an AIDS-related complex is reported. In this patient certain symptoms common to both diseases, i.e. weakness, myalgia and muscle atrophy were accentuated, whereas other symptoms pathognomic of the human immunodeficiency virus (HIV) infection, i.e. lymphoadenopathies and weight loss, were less pronounced by the high levels of circulating adrenal steroids. Ketoconazole was administered po in order to block adrenal steroidogenesis, the drug caused a remarkable fall of cortisol serum concentrations, but was unable to modify significantly the immunological pattern of the patient. Our data suggest that changes of serum adrenal steroid levels have little effect on the immune network of patients with AIDS.

AIDS-Related Complex↗
PubMed1992

Cardiomyoplasty does not preclude heart transplantation.

Stimulated skeletal muscle grafts have been proposed to improve left ventricle function in patients with severe myocardial failure. In 1 particular case reported here, however, the postoperative functional improvement was only transient and disabling heart failure recurred after 9 months in spite of a vigorous latissimus muscle contraction. Heart transplantation was proposed to this patient and performed successfully. Technically, the key to heart removal depends on the retrograde dissection of the ventricular cavities, starting from the right atrioventricular groove. The intraoperative observations confirmed the viability of the latissimus dorsi muscle, inefficient on a highly dilated cardiomyopathy. Histopathological examination of the latissimus dorsi muscles showed that the transformation process of the stimulated muscle was good. Thus, severe cardiac dilatation seems to be one of the limitations of cardiomyoplasty. Cardiomyoplasty, when it fails, does not preclude heart transplantation. The histochemical studies confirm the electrophysiologic principle of cardiomyoplasty in humans.

Assisted Circulation↗
PubMed1992

In vivo modulation of lymphokine-activated killer cell activity by cell wall components of Candida albicans.

We have previously reported that inoculating CD2F1 mice intraperitoneally with five doses of 2 x 10(7) inactivated Candida albicans (CA) cells was associated with the induction of lymphokine-activated killer (LAK)-like effectors. In this study we investigated the ability of some purified cell wall components of CA (CA-CW) to induce LAK-like cells in vivo. Multiple administrations of glucan ghost (GG), a mannoprotein mixture (MP) and a low-protein mannan fraction (M) at variance with whole CA did not induce LAK-like cells in the peritoneal cavity. However, the broad-spectrum antitumor cytotoxicity induced by CA could be recalled to a high level by a booster dose of MP and M, but not GG, given up to 70 days after the multiple CA-treatment. This induced cytotoxicity was maximum when the booster was given on Day +14 after CA-treatment and minimum on Day +70. In CA-treated mice, inoculated on Day +30 with CA or MP, LAK-like cytotoxicity was already significantly increased 4 hr after the booster, but the maximum value was reached at 24 hr. Anti-mannan antibodies did not interfere with LAK-like cells induction by CA because splenectomy before CA-treatment or passive administration of anti-mannan antibodies had no effect on the rapid activation of cytotoxicity by CA or a booster dose of MP. Administration of recombinant human interleukin-2 (rhIL-2) to CA-treated mice induced a higher level of NK activity than that induced by the same dose in untreated control mice, but did not activate LAK-like effectors. The results indicate that LAK-like effectors are easily generated in the peritoneal cavity by a booster with a defined antigenic constituent of CA cell wall for a long period in CA-sensitized mice.

Animals↗
PubMed1992

Pregnancy modulates the expression of beta-N-acetylhexosaminidase in rat serum and tissues.

1. beta-N-Acetylhexosaminidases in maternal rat serum were separated by DEAE-cellulose chromatography and compared with those of adult rat serum. 2. In pregnant serum there is an increase of the isoenzymes which are entirely composed of beta-subunits (B and intermediate forms). 3. These alterations could be compared to those already described in human pregnancy. 4. The levels of beta-N-acetylhexosaminidase and the relative expression of alpha- and beta-subunits in normal and pregnant serum correlate with the above isoenzyme expression. 5. The increase of B and intermediate forms as well as the increase of specific activity during pregnancy was not peculiar to maternal serum but was also demonstrated in several foetal tissues and in maternal tissues, in which cases the beta-N-acetylhexosaminidase isoenzyme patterns closely resemble the foetal ones rather than those of the adult rat tissues. 6. These analogies strongly suggest that the expression of beta-subunit of beta-N-acetylhexosaminidase is regulated by hormones or other factors related to pregnancy.

Animals↗
PubMed1992

Circadian patterns of drinking and eating in pygmy goats.

The eating and drinking patterns of pygmy goats fed ad lib and kept on a 12 h light/12 h dark cycle were recorded and analyzed. Eighty-four percent of drafts (drinking bouts) were associated with meals (feeding bouts). Only 42% of meals were associated with drafts. In the light phase meals associated with drafts were significantly larger than meals not associated with drafts, suggesting that meal size is increased by water intake around meals. Cumulative food intake was positively correlated with cumulative water intake, but the correlation was weaker during the dark phase than during the light phase. The results demonstrate that water intake in ruminants is associated with food intake, but the link between water and food intake seems to be more pronounced during the light phase than during the dark phase.

Animals↗
PubMed1992

Functional analysis of the pertussis toxin promoter.

The expression of the pertussis toxin ptx operon is positively regulated in cis by a promoter region of about 170 base pairs and in trans by the bvg locus, which codes for the transcriptional activator protein BvgA. The promoter contains two direct repeats which are essential for its activity. When the position of these direct repeats relative to the transcription start point was changed, the activity of the promoter was strongly impaired. The repeated sequences therefore do not represent enhancer-like elements similar to those which have been identified in other positively regulated promoters; instead, the integrity of the whole promoter region seems to be an important feature of ptx regulation. A transcription interference assay was carried out to analyze in vivo binding of regulatory proteins to the ptx promoter. The results suggest that the direct repeats are the recognition sequence of a protein, which binds to them only under conditions in which the promoter is activated. In vitro DNA binding experiments with BvgA protein purified from an overproducing Escherichia coli strain were performed. However, no binding of BvgA to the ptx promoter was observed under conditions where binding of BvgA to the fha and bvg promoters occurred. This suggests that factors in addition to the bvg system are involved in the regulation of the Bordetella virulence regulon.

Bordetella pertussis↗
PubMed1992

Bone mass status in different degrees of chronic renal failure.

Bone mineral density (BMD) was evaluated in 69 patients with chronic renal failure (CRF) and in healthy controls matched for age, sex, and, for women, menopausal status. Both appendicular (predominantly cortical) and axial (predominantly trabecular) bone mass were measured. Appendicular BMD was measured by single photon absorptiometry on the distal forearm and axial BMD was measured by dual photon absorptiometry on the lumbar spine. Patients were divided into three groups on the basis of creatinine clearance: group 1, 58 to 36 ml/min; group 2, 30 to 18 ml/min; group 3, 15 to 9 ml/min. Both appendicular and axial BMD decreased with the worsening of renal failure. Parathyroid hormone levels were inversely correlated with the values of appendicular BMD. BMD values were significantly lower in postmenopausal than in premenopausal women. Months of menopause were inversely correlated with axial BMD values. Appendicular BMD was lower in CRF patients than in controls, and both appendicular and axial BMD were significantly lower in postmenopausal uremic women than in postmenopausal healthy women.

Absorptiometry, Photon↗
PubMed1992

Circadian rhythm of calcitonin gene-related peptide in uncomplicated essential hypertension.

OBJECTIVE: To assess the existence of an altered circulating pattern of calcitonin gene-related peptide (CGRP) in hypertension. DESIGN: The 24 h variation in plasma CGRP was measured and compared in 10 patients affected by uncomplicated essential hypertension and in nine age- and sex-matched healthy volunteers. The diurnal variations in blood pressure, atrial natriuretic peptide (ANP), plasma renin activity (PRA), plasma aldosterone and plasma cortisol were also assessed. METHODS: Recumbency studies were performed under standardized, drug-free conditions beginning at 0800 h. Venous samples were drawn every 4 h for 24 h and hormone levels were assessed with specific radioimmunoassays. The blood pressure was measured every 15 min with a SpaceLabs 90207 monitor. RESULTS: The mean 24-h plasma CGRP concentrations were significantly lower in the hypertensive group than in the control group. In both groups a circadian rhythm was present with the same pattern, but at a lower level in hypertension. A temporal sequence starting with the nocturnal rise in plasma CGRP concentrations and progressing with the elevations of ANP, PRA, and plasma aldosterone and cortisol was apparent in both groups. The nocturnal rise in the CGRP and ANP concentrations coincided with the blood pressure and the heart rate falls. CONCLUSIONS: Our data show that CGRP is lower than normal but maintains its circadian variability and its relationship with the diurnal variations in blood pressure and other hormones known to be active on the cardiovascular system.

Adult↗
PubMed1992

Effect of endothelin 1 on plasma glucose and lipid levels in pygmy goats.

The effect of endothelin 1, a recently discovered vasoconstrictor hormone, on levels of plasma glucose and lipids was investigated in pygmy goats. Endothelin 1 was injected intraperitoneally (1.72 micrograms/kg BW) and blood samples were taken by puncturing the jugular vein immediately before and 60, 150 and 240 min post injection. Endothelin 1 in comparison to vehicle significantly increased plasma glucose and FFA levels, whereas plasma triglycerides were significantly reduced. Thus, beside its vasoconstrictive action, endothelin 1 also has metabolic effects. Whether these effects are directly caused by endothelin 1 or whether they are due to a release of a metabolic hormone, e.g. epinephrine, remains to be investigated.

Animals↗
PubMed1992

delta-Opioid receptors and the secretion of growth hormone in man: effect of opioid delta-receptor agonist deltorphin on GH responses to GH-releasing hormone and insulin-induced hypoglycemia.

To investigate the role of delta-opioid receptors in the modulation of growth hormone (GH) secretion, we compared in normal subjects the effect of the highly selective delta-opioid receptor agonist Deltorphin (DT) on the GH secretion responses to pituitary (GH-releasing hormone, GHRH)- and hypothalamic (insulin-induced hypoglycemia, IIH)-mediated stimuli. DT blunted the GH response to IIH, whereas it had no effect on the GH response to GHRH. It is concluded that in man DT-induced activation of delta-opioid receptors exerts an inhibitory action on hypoglycemia-stimulated GH secretion. Based on the lack of an effect of DT on the GH response to GHRH, we suggest that DT may modulate the secretion of GH through suprapituitary mechanisms.

Adult↗
PubMed1992

Bilateral and simultaneous inferior petrosal sinus sampling in the early diagnosis of an ACTH-producing pituitary microadenoma and its detection by magnetic resonance one year later.

This study describes a case of pituitary-dependent Cushing's syndrome where standard biochemical and radiological techniques were discordant in localizing the origin of the autonomous adrenocorticotropic hormone (ACTH) hypersecretion in the pituitary. Hormonal evaluation suggested a pituitary genesis for the disease, but both sellar computed tomography and cranial magnetic resonance (MR) were unable to give clear-cut evidence for a pituitary neoplasm. Simultaneous and bilateral inferior petrosal sinus sampling (SBIPS) correctly identified the left side of the pituitary gland as the source of autonomous ACTH production. One year later, the shaded signs of a pituitary lesion in the left side of the gland were seen with MR imaging, and a 0.5-cm in height adenoma was surgically removed. At the 2-year follow-up the patient's symptoms had completely disappeared, and her menses were restored. In this case, SBIPS correctly diagnosed the presence of an ACTH-secreting pituitary microadenoma one year before shaded signs of the pituitary lesion appeared with MR imaging. This is a clear-cut demonstration of the accuracy of the SBIPS technique in localizing small pituitary lesions.

Adenoma↗
PubMed1992

Effect of deltorphin on pituitary-adrenal response to insulin-induced hypoglycemia and ovine corticotropin-releasing hormone in healthy man.

To determine the role of delta-opioid receptors in the modulation of hypothalamic-pituitary-adrenal activity, we studied in normal subjects the effect of the highly selective delta-opioid receptor agonist deltorphin (DT) on the secretion of ACTH, cortisol, and arginine vasopressin in response to insulin-induced hypoglycemia. In an attempt to clarify the site of opiate modulation of ACTH secretion, we also studied in normal subjects the effect of DT on the ACTH response to ovine CRH-41. DT blunted the ACTH, cortisol, and arginine vasopressin responses to insulin-induced hypoglycemia, whereas it had no effect on the ACTH and cortisol responses to CRH. We conclude that DT-induced activation of delta-opioid receptors exerts an inhibitory influence on hypoglycemia-stimulated ACTH secretion. Based on the lack of an effect of DT on the ACTH response to CRH, we postulate that DT may modulate the secretion of ACTH through suprapituitary mechanisms.

Adrenocorticotropic Hormone↗