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Biomedical subjects

F Rossi

Publications and source records attributed to F Rossi.

At least 559 records · Page 31Linked to original sources
PubMed1989

Immunohistochemical investigations of the human palatine tonsil from surgical specimens using polyclonal and monoclonal antikeratin antibodies.

The keratinization process of tonsillary epithelium in patients with different age, who underwent surgery because of chronic inflammatory processes, has been studied by employing low (40 KD), medium (52-56-58 KD), high (56-64 and 68 KD) as well as broad spectrum antikeratin antibodies. The findings thus obtained outline the various keratin patterns of the tonsil in the outer covering and, even more, in the crypt labyrinth wall. These findings have been compared with those obtained by histochemical reactions for acid phosphatase and non-specific esterase activities (Favrz et al. 1986 II). In crypt epithelium keratinization, 56-64 KD keratins are involved in cells where also high enzymic activities are taking place, namely 1. in those elements delimiting the lumen as well as in those belonging to the reticulum mesh which are nearest to it and host lymphoid elements active in immunity reactions; 2. in elements at the bottom of small and large crypts, where excavation continues into the lymphoid tissue and interfollicular spaces. 68 KD keratin, although present in lower amounts, is synthesized almost everywhere, but only irregularly. It marks surface epithelium surrounding some dermal papillae, some meshes of the crypt reticulum, the "gallery" bottom as well as elements of interfollicular proliferation developing in the lymphoid tissue like arborescence. The path of congested blood vessels in the crypt wall towards the surface is marked by keratinized epitheliocytes. 56-64 KD keratin is present in the most superficial elements and is generally accompanied by the wall growing thinner, its blistering and breaking. The most frequent pathologic alterations of the epithelium (like cellular hypertrophy) involve variations in cytoplasm keratin pattern, in still un-flattened polyhedral elements of the intermediate layers.

Adolescent↗
PubMed1989

[Mesenteric hematoma disclosing periarteritis nodosa. Apropos of a case].

A 59 year old woman, asthmatic and hypertensive, presented with unexplained abdominal pains and signs of internal hemorrhage. Ultrasonography and CT demonstrated mesenteric hematomas. Theses hematomas had been related to fissured aneurysms of branches of superior mesenteric artery in course of polyarteritis nodosa and proved by angiography.

Aneurysm↗
PubMed1989

[An unusual mechanism of lead poisoning. Presentation of a case].

A case is described, that came to our attention for suspected acute intermittent porphyria, with abdominal pain and ascending tetraplegia. The patient (HIV positive and with a HBsAg positive chronic aggressive hepatitis) was a heroin addict. In urine: high porphyrins with extremely increased delta amino-levulinic acid (ALA) and normal porphobilinogen. High protoporphyrin was present in blood red cells. The lead poisoning was confirmed by a very low ALA-dehydratase activity in erythrocytes and a high content of lead in urine and plasma. With Ca-versenate and penicillamine the abdominal and neurological symptoms rapidly disappeared. The possibility of contact with lead, professional or environmental, was ruled out. It was found however, that shortly before the appearance of symptoms, the patient had used a batch of unrefined brown sugar heroin, which was probably mixed with lead salts. It is noteworthy that during the same period, other young heroin addicts died with similar symptoms.

Adult↗
PubMed1989

Cerebral spinal fluid IgG production in HIV-positive patients.

A brief characterization of 27 neurologic syndromes occurring in 44 AIDS patients during two years is presented. In 4 out of 7, intrathecal Ig synthesis was demonstrated without the CSF cell count and blood brain barrier values being within a normal range. Ig intrathecal formation was also observed in 2 LAS patients without neurological symptoms. Similar changes in CSF findings occur in other subacute encephalitis, particularly in multiple sclerosis. Activation of CSF B-cells or their depression due to impairment of CD8 T-lymphocytes was indicated as the cause of this phenomenon. In the Authors' opinion this explanation is somewhat general. The possibility of an immune response in CNS was clearly demonstrated, but in the CSF neither B-cells nor Ig producing plasma cells are evident. In addition, it should be noted that the reliability of blood brain barrier and Ig intrathecal assessment procedures is doubtful in ADC disease, because of the severe alterations in serum albumin and Ig concentrations seen in these patients.

AIDS-Related Complex↗
PubMed1989

Life-threatening intracranial bleeding associated with the presence of an antifactor VII autoantibody.

This is a report of a 62-year-old male patient who had a bleeding disorder due to the presence of a factor VII (proconvertin) inhibitor. After treatment with a high-dose intravenous (IV) immunoglobulin failed and a life-threatening intracranial hemorrhage occurred, plasma exchanges were performed and immunosuppressive therapy was given. The factor VII inhibitor promptly disappeared, and the patient's parameters of hemostasis became normal. Even though a relapse occurred some months later, the patient responded to immunosuppressive therapy. No underlying disorder was evidenced after 17 months of follow-up.

Autoimmune Diseases↗
PubMed1988

Activation of human neutrophils by substance P. Effect on oxidative metabolism, exocytosis, cytosolic Ca2+ concentration and inositol phosphate formation.

The neuropeptide substance P (SP), which has been suggested to mediate neurogenic inflammation, induces in human neutrophils the activation of the respiratory burst measured as O2 consumption and H2O2 production, and a cytochalasin B-dependent secretion of specific and azurophilic granules. The SP(4-11) fragment is much more stimulant than the entire molecule, whereas the SP(1-4) fragment is inactive. The respiratory and secretory response to SP are associated with an activation of phosphoinositide turnover, of Ca2+ influx and release from intracellular stores. Pertussis toxin inhibits 70% of the respiratory response and the residual 30% activity remains, even increasing 10-fold the concentration of the toxin. 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine, a putative inhibitor of protein kinase C, does not modify the respiratory response to SP. Cytochalasin B significantly depresses the activation of the respiration by SP, whereas it moderately enhances the activation of phosphoinositide turnover and potentiates the increase of intracellular Ca2+ concentration. The results are discussed in relation to the receptor apparatus involved in SP activity, the signal transduction sequence activated by SP for the stimulation of NADPH oxidase, and the role of cell response to SP in the inflammatory process.

Calcium↗
PubMed1988

Antagonist action of imidazobenzodiazepine Ro 15-4513 on ethanol-induced alterations of saccadic eye movements in the pigmented rat.

Following an intraperitoneal injection of ethanol (1 g/kg), spontaneous saccades performed by pigmented rats showed a backward post-saccadic drift which was still present 45 min after the administration. When 5 mg/kg of Ro 15-4513 were injected, 15 min after ethanol, there was an immediate remarkable reduction in post-saccadic drift amplitude, with a full recovery in about 30 min after Ro 15-4513 administration. This drug is thus able to reverse the effect of ethanol and to restore effectively a mechanism of motor integration.

Animals↗
PubMed1988

Activation of NADPH-dependent superoxide production in plasma membrane extracts of pig neutrophils by phosphatidic acid.

Phosphatidic acid (PA), a molecule that is rapidly produced by the stimulated turnover of phospholipids in a variety of cells including blood neutrophils, elicited NADPH-dependent superoxide anion (O2-) production in detergent extracts from membranes of resting pig neutrophils. The stimulatory effect of PA was independent of cytosolic factors, differing from arachidonic acid and sodium dodecyl sulfate which, on the contrary, absolutely required the presence of cytosol to elicit the same result. The O2(-)-forming activity of the detergent extract activable by PA, as that by sodium dodecyl sulfate and arachidonic acid plus cytosol, was found in the chromatographic fractions containing cytochrome b558 and presented a chromatographic profile identical to that of the activated NADPH oxidase, which was obtained from neutrophils prestimulated with phorbol 12-myristate 13-acetate. The PA-induced NADPH-dependent O2(-)-forming activity showed kinetic properties and sensitivity to the inhibitors similar to the classical ones of the activated neutrophil NADPH oxidase. The data suggest that, in this cell-free system, PA may stimulate O2- formation by direct interaction with latent NADPH oxidase of neutrophils or with some of its regulatory components.

Animals↗
PubMed1988

Fluoride can activate the respiratory burst independently of Ca2+, stimulation of phosphoinositide turnover and protein kinase C translocation in primed human neutrophils.

Evidences have been provided in our laboratory that in neutrophils different signal transduction sequences for the activation of O2(-)-forming NADPH oxidase can be triggered by the same stimulus (Biochem. Biophys. Res. Commun. 1986, 135, 556-565; 1986, 135, 785-794; 1986, 140, 1-11). The results presented here show that the transduction sequence triggered by fluoride via dissociation of G-proteins and involving messengers produced by stimulation of phosphoinositide turnover, Ca2+ changes and translocation of protein kinase C from the cytosol to the plasmamembrane, can be bypassed when a primed state of neutrophils is previously induced. In fact: i) fluoride causes a pertussis toxin insensitive and H-7 sensitive respiratory burst in human neutrophils, which is linked to the activation of hydrolysis of PIP2, rise in [Ca2+]1 and translocation of PKC. In Ca2+-depleted neutrophils these responses to fluoride do not occur and are restored by addition of CaCl2. ii) The pretreatment of Ca2+-depleted unresponsive neutrophils with non stimulatory doses of PMA restores the activation of the NADPH oxidase by fluoride but not the turnover of phosphoinositides and PKC translocation. The nature of the alternative transduction sequence, the reactions different from phospholipase C activated by G-protein for the alternative sequence and the role of these discrete pathways for NADPH oxidase activation are discussed.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

Prenatal and postnatal thallium exposure in rats: effect on development of vasomotor reactivity in pups.

Vasomotor reactivity has been evaluated in rats exposed perinatally and postnatally to thallium sulphate (1 mg/dl in their drinking water ad libitum). Prenatal and postnatal exposure to thallium did not modify the values of the systolic arterial blood pressure on the 30th and 60th day in pups of normotensive and DOCA-hypertensive rats. The hypertensive responses induced by endosinusal carotid hypotension and by 1-noradrenaline in pups of normotensive and DOCA-hypertensive rats, exposed or not exposed to thallium sulphate, were more intensive on the 60th than on the 30th day. Similar effects were observed for the hypotensive responses induced by 1-isoprenaline and acetylcholine. Prenatal exposure to thallium did not modify hypertensive responses induced by endosinusal carotid hypotension on the 30th and 60th days, but it caused a decrease of hypertensive responses induced by 1-noradrenaline on the 30th and 60th days and hypotensive responses induced by 1-isoprenaline and acetylcholine exclusively on the 60th day. Postnatal exposure to thallium did not modify hypertensive responses induced by endosinusal carotid hypotension and hypotensive responses induced by acetylcholine, but it caused a decrease of hypertensive responses induced by 1-noradrenaline on the 30th and 60th days in pups of normotensive rats and exclusively on the 60th day in pups of DOCA-hypertensive rats. Moreover, postnatal exposure to thallium caused a decrease of the hypotensive response induced by 1-isoprenaline exclusively on the 60th day. Our findings show that prenatal and postnatal exposure to thallium sulphate modifies the rat's developing vascular autonomic nervous system with a reduction of the alpha, beta-adrenergic and muscarinic vasomotor reactivity.

Animals↗
PubMed1988

Relationships between lung computed tomographic density, gas exchange, and PEEP in acute respiratory failure.

Twenty-two patients with acute respiratory failure underwent lung computed tomography (CT) and physiological measurements at 5, 10, and 15 cm H2O positive end-expiratory pressure (PEEP) to investigate the relationship between morphology and function. Lung densities were primarily concentrated in the dependent regions. From the frequency distribution of CT numbers (difference in x-ray attenuation between water and lung) and lung gas volume measurements the authors obtained a quantitative estimate of normally inflated, poorly inflated, and non-inflated lung tissue weight. This estimated average lung weight was increased twofold above normal and excess lung weight correlated with the mean pulmonary artery pressure (P less than 0.01). Venous admixture correlated with the non-inflated tissue mass (P less than 0.01). Increasing PEEP caused progressive clearing of radiographic densities and increased the mass of normally inflated tissue (anatomic recruitment), while reducing venous admixture. The cardiac index decreased after increasing PEEP while oxygen delivery was unchanged. The authors conclude that CT scan lung density and oxygen exchange efficiency are correlated; the main effect of augmenting PEEP is to recruit perfused alveolar units that were previously collapsed.

Acute Disease↗