Showing papers by "University of Florence published in 1988"

IL-4 is an essential factor for the IgE synthesis induced in vitro by human T cell clones and their supernatants.

Abstract: The property of 109 CD4+ T cell clones (TCC) to induce IgE synthesis in vitro in human B cells was compared with their ability to produce IL-2, IL-4, and IFN-gamma in their supernatants (SUP) after 24-h stimulation with PHA. A significant positive correlation was found between the property of TCC to induce or enhance spontaneous IgE synthesis and their ability to release IL-4. In contrast, there was an inverse relationship between the IgE helper activity of TCC and their ability to release IFN-gamma, whereas no statistical correlation between the property to induce IgE synthesis and to produce IL-2 was observed. The ability of PHA-SUP from 71 CD4+ TCC to induce IgE synthesis in B cells was also investigated. Twenty-nine SUP (all derived from TCC active on IgE synthesis) induced production of substantial amounts of IgE in target B cells. There was a correlation between the amount of IgE synthesized by B cells in response to these SUP and their IL-4 content. An even higher correlation was found between the IgE synthesis induced by these SUP and the ratio between the amount of IL-4 and IFN-gamma present in the same SUP. Like IL-4-containing SUP, rIL-4 also showed the ability to induce IgE production in B cells from both atopic and nonatopic donors. The addition to B cell cultures of anti-IL-4 antibody virtually abolished not only the IgE synthesis induced by rIL-4, but also that stimulated by TCC and their SUP. In contrast, the IgG synthesis induced by TCC SUP was not or only slightly inhibited by the anti-IL-4 antibody. These data indicate that IL-4 is an essential mediator for the IgE synthesis induced in vitro by human TCC and their SUP in the absence of a polyclonal activator, whereas IFN-gamma seems to exert a negative regulatory effect on the production of IgE.

Presence of kynurenic acid in the mammalian brain.

Abstract: Kynurenic acid, a tryptophan metabolite able to antagonize the actions of the excitatory amino acids, has been identified and measured for the first time in the brain of mice, rats, guinea pigs, and humans by using an HPLC method. Its content was 5.8 +/- 0.9 in mouse brain, 17.8 +/- 2.0 in rat brain, 16.2 +/- 1.5 in guinea pig brain, 26.8 +/- 2.9 in rabbit brain, and 150 +/- 30 in human cortex (pmol/g wet wt. mean +/- SE). The regional distribution of this molecule was uneven. In rats, guinea pigs, and rabbits, the brainstem was the area richest in this compound. Tryptophan administration (100-300 mg/kg, i.p.) to rats resulted in a significant increase of the brain content of kynurenic acid. Similarly, 1 h after probenecid administration (200 mg/kg, i.p.), the brain content of kynurenate increased by fourfold, thus suggesting that its turnover rate is relatively fast.

Excitatory amino acid release from rat hippocampal slices as a consequence of free-radical formation.

Abstract: The release of D-[3H]aspartate, [3H]noradrenaline, and of endogenous glutamate and aspartate from rat hippocampal slices was significantly increased when the slices were incubated with xanthine oxidase plus xanthine to produce superoxide and hydroxyl free radicals locally. Allopurinol, a specific xanthine oxidase inhibitor, the hy-droxyl-radical scavenger D-mannitol, or the superoxide-radical scavenger system formed by superoxide dismutase plus catalase prevented this release. These results suggest that endogenous excitatory amino acids are released consequent to the formation of free radicals. The excess of glutamate and aspartate released by this mechanism could be one of the factors contributing to the death of neurons after anoxic or ischemic injuries.

Profiles of lymphokine activities and helper function for IgE in human T cell clones.

Abstract: A large panel of phytohemagglutinin (PHA)-induced T cell clones (690 in total), established from four different human lymphoid tissues (peripheral blood, tonsils, lymph nodes and spleens) by a high-efficiency cloning technique, was characterized according to their pattern of lymphokine production. The majority of both CD4+ and CD8+clones from all lymphoid tissues produced interleukin (IL) 2 and/or interferon (1FN)-γ response to 24-h stimulation with PHA. In contrast, higher proportions of IL4-producing clones were found among CD4+clones from tonsils and spleens than from peripheral blood and lymph nodes, whereas only a minority of CD8+ clones from all lymphoid tissues were found to produce IL4. It was not possible to divide the CD4+ (helper/inducer) clones on the basis of their pattern of lymphokine activity into two clear-cut groups analogous to Thl and Th2 helper clones described in mice. Although 21 out of 503 (4%) CD4+ T cell clones produced IL4, but not IFN-γ or IL2, and 208 (41%) produced IL2 and/or IFN-γ, but not IL4, a total number of 185 (37%) CD4+ clones showed the ability to produce IL4 plus IL2 and/or IFN-γ. All types of CD4+ T cells (as classified according to their pattern of lymphokine activity) provided help for IgG production in allogeneic B cells. In contrast, helper function for IgE was detectable only among the IL4-producing clones. However, the proportion of CD4+ clones providing help for IgE synthesis was significantly lower among those producing IL4 and IFN-γ or IL4, IL2 and IFN-γ than among those producing IL4 alone or IL4 and IL2. Thus, a clear-cut dichotomy between IL4- and IFN-γ-producing Th cells, as found in mice, does not seem to exist in humans. However, IL4 and IFN-γ, even if not always produced by distinct T cell subsets, appear to regulate reciprocally the synthesis of IgE in humans as well.

Foods and respiratory allergy

Abstract: Foods may induce respiratory symptoms by both reaginic and nonreaginic mechanisms. Asthma is one of the most common respiratory manifestations in children, and it is well known that many factors may provoke an attack. When considering the relationship between foods and asthma, we must keep in mind that food allergy may coexist with an inhalant allergy and that other nonallergens, such as pollutants, smoke, or additives, may modulate or modify bronchial reactivity and thus favor the food allergen action. In a study using clinical history, prick test, radioallergosorbent test, and double-blind food challenge, we demonstrated respiratory symptoms related to food allergy in 13 of 140 (9.2%) children with asthma. Asthma, in particular, was demonstrated in 8 of 140 (5.7%) patients. Food allergy respiratory symptoms are, in our experience, almost always associated with other clinical manifestations (e.g., cutaneous, gastrointestinal). The recognition of food-dependent IgE-mediated respiratory symptoms is essentially limited to those cases characterized by food allergy with asthmatic expression. It is possible, however, that in many cases foods may have a nonspecific role in the determination of asthma or in the preparation of bronchi for the possible consequent stimulus.

Patellofemoral functional results and complications with the posterior stabilized total condylar knee prosthesis

Abstract: The authors reviewed 73 knee arthoplasties performed with the Posterior Stabilized Total Condylar prosthesis, with an average follow-up period of 5.5 years. The function of the patellofemoral articulation was specifically analyzed. Patients with documented or suspected tibiofemoral problems were excluded. Using the Hospital for Special Surgery knee rating system, 48 knees (66%) had excellent, 20 had good (27%), and 5 (7%) had fair results. Patients with unilateral disease were able to negotiate stairs and transfer normally in 64% and 100% of the cases, respectively. The most frequent patellofemoral problem was impingement (21%), but reoperation was needed in only one patient. Stress fracture of the patella and subluxation were rare. A medial tilt of the patella on the axial view had no apparent ill effect. The patella was lowered 12 mm on average as a consequence of the standard bone resection sequence and insertion of the tibial component. The patella was significantly lower in patients with impingement than in normal joints. Routine complete patellofemoral resurfacing is advised in total knee joint arthroplasty. Complications are infrequent with appropriate prosthetic design and due technical care.

Clinical Pharmacokinetics of Valproic Acid — 1988

Abstract: Sodium valproate (valproic acid) has been widely used in the last decade and is now considered a relatively safe and effective anticonvulsant agent. Recently, several investigators have proposed its use in the treatment of anxiety, alcoholism and mood disorders, although these indications require further clinical studies.

Interrater Reliability in Assessing Functional Systems and Disability on the Kurtzke Scale in Multiple Sclerosis

Abstract: Interexaminer agreement in the use of quantitative scales for the evaluation of neurological deficits is essential to the reliability of clinical data from cooperative studies on multiple sclerosis. In this study, four neurologists, arranged into six pairs, examined 24 patients with definite multiple sclerosis and assessed each functional system and disability on the Kurtzke scale. As expressed by the kappa index, interobserver agreement was rather low, ranging from 30% to 50%. Sensory and mental functions turned out to be the most variable. The kappa indexes reached values above 85%, when raters who differed by no more than one point were considered as agreeing. A point difference on the scale of, at most, two units seemed to be a reliable index of clinical change. Moreover, these results pointed to the necessity for a specific training program for raters and for periodic control of interobserver variability in multicenter surveys.

Incidence of stroke in young adults in Florence, Italy.

Abstract: A population-based study specifically addressing stroke in young adults (aged 15-44 years) was conducted in Florence, Italy, from 1983 to 1985. We identified 47 cases of first stroke by means of a daily check of the medical facilities of the city and nearby towns and a review of death certificates. Patients were assessed by a neurologist shortly after the onset of the stroke, and computed tomography or autopsy was performed in 96%. The average annual incidence rate for all stroke (cases per 100,000 population per year) was 9.0 (95% confidence interval 5.8-13.4) for males and 8.7 (95% confidence interval 5.5-13.0) for females. The average annual incidence rates for the pathologic types of stroke were 3.4 for cerebral infarction, 3.2 for subarachnoid hemorrhage, and 1.9 for intracerebral hemorrhage. The case-fatality ratio was 23.4% at 1 month. Among patients with ischemic strokes, atherosclerosis and cardiac disease accounted for 50% of the cases. Based on angiography or autopsy findings, aneurysm or arteriovenous malformation were demonstrated in 88% of the patients with subarachnoid hemorrhage. In 50% of the patients with intracerebral hemorrhage, no cause of bleeding was detected. Our study may supply information about stroke pathologic types in an unselected series of young adults.

Riemannian Metrics on Tangent Bundles

Abstract: Some «natural» metrics on the tangent and on the sphere tangent bundle of Riemannian manifold are constructed and studied via the moving frame method.

Heme pocket interactions in cytochrome c peroxidase studied by site-directed mutagenesis and resonance Raman spectroscopy.

Abstract: Resonance Raman spectra are reported for FeII and FeIII forms of cytochrome c peroxidase (CCP) mutants prepared by site-directed mutagenesis and cloning in Escherichia coli. These include the bacterial "wild type", CCP(MI), and mutations involving groups on the proximal (Asp-235----Asn, Trp-191----Phe) and distal (Trp-51----Phe, Arg-48----Leu and Lys) side of the heme. These spectra are used to assess the spin and ligation states of the heme, via the porphyrin marker band frequencies, especially v3, near 1500 cm-1, and, for the FeII forms, the status of the Fe-proximal histidine bond via its stretching frequency. The FeII-His frequency is elevated to approximately 240 cm-1 in CCP(MI) and in all of the distal mutants, due to hydrogen-bonding interactions between the proximal His-175 N delta and the carboxylate acceptor group on Asp-235. The FeII-His RR band has two components, at 233 and 246 cm-1, which are suggested to arise from populations having H-bonded and deprotonated imidazole; these can be viewed in terms of a double-well potential involving proton transfer coupled to protein conformation. The populations shift with changing pH, possibly reflecting structure changes associated with protonation of key histidine residues, and are influenced by the Leu-48 and Phe-191 mutations. A low-spin FeII form is seen at high pH for the Lys-48, Leu-48, Phe-191, and Phe-51 mutants; for the last three species, coordination of the distal His-52 is suggested by a approximately 200-cm-1 RR band assignable to Fe(imidazole)2 stretching.(ABSTRACT TRUNCATED AT 250 WORDS)

Posteriorly stabilised total-condylar knee replacement. Three to eight years' follow-up of 85 knees

Abstract: We have reviewed 85 knees in 71 patients after total-condylar posteriorly stabilised (Insall-Burstein) knee replacement with an average follow-up of five years. Excellent or good results were obtained in 90% with an average maximum flexion of 98 degrees. The four poor results (5%) included two with deep infection, one with patellar dislocation and one with loosening. Four other knees (5%) showed signs of probable tibial loosening, but the patients were asymptomatic, the clinical results had not deteriorated with time and lucent lines had not progressed. Varus alignment of the knee and a varus tilt of more than 2 degrees of the tibial component correlated with the incidence of lucent lines around the tibial implant. No patellar stress fractures were seen but impingement symptoms were present in 20%, although they were troublesome in less than half of them. The virtue of the prosthesis lies in its versatility for use in the severely deformed joint.

Secretion, pain and sneezing induced by the application of capsaicin to the nasal mucosa in man.

Abstract: 1. Topical application of capsaicin to the human nasal mucosa induced a burning sensation and sneezing. A dose-dependent seromucous nasal secretion was also observed. Capsaicin (75 micrograms) was more potent than methacholine (50 mg) in producing nasal secretion, while topical histamine (200 micrograms), substance P (135 micrograms) and calcitonin gene-related peptide (36 micrograms) did not induce rhinorrhea. 2. Pretreatment with either topical ipratropium bromide, systemic dexchlorpheniramine or indomethacin did not influence the effects induced by capsaicin. Topical pretreatment with lidocaine inhibited the painful sensation but failed to block the rhinorrhea. Desensitization to the effects of capsaicin occurred following 4-5 subsequent applications, and full recovery was observed within 30-40 days. 3. It is proposed that the effects of capsaicin in human nasal mucosa are due to excitation of primary afferent neurones that (a) convey burning and painful sensation, (b) evoke a sneezing reflex and (c) induce nasal secretion by releasing transmitter(s) from their peripheral terminals.

The effect of omega conotoxin GVIA, a peptide modulator of the N-type voltage sensitive calcium channels, on motor responses produced by activation of efferent and sensory nerves in mammalian smooth muscle.

Abstract: 1. The effect of omega-conotoxin (CTX) GVIA, a peptide which blocks neuronal calcium channels, were investigated on nerve-mediated motor responses in a variety of isolated smooth muscle preparations from rats and guinea-pigs. 2. In the rat or guinea-pig isolated vas deferens CTX (1 nM − 1 μM) produced a concentration and time-related inhibition of the response to field stimulation, while the responses to KCI, noradrenaline or adenosine triphosphate were unaffected. In the presence of CTX a series of tetrodotoxin-resistant contractions could be elicited by field stimulation by increasing pulse width and/or voltage. 3. In the rat or guinea-pig isolated urinary bladder, CTX produced a concentration and time-dependent inhibition of twitch responses to field stimulation without affecting the response to exogenous acetylcholine. In the rat bladder the maximal effect did not exceed 25% inhibition while a much larger fraction of the response (about 70%) was inhibited in the guinea-pig bladder. The CTX-resistant response was abolished, in both tissues, by tetrodotoxin. 4. The effects of CTX in the rat bladder were also studied with a whole range of frequencies of field stimulation (0.1–50 Hz). Maximal inhibition was observed toward contractions elicited at frequencies of 2–5 Hz. At low frequencies the inhibitory effects of CTX and atropine were almost additive while at high frequencies of stimulation a large component of the atropine-sensitive response was CTX-resistant. 5. In the rat isolated proximal duodenum, field stimulation in the- presence of atropine and guanethidine produced a primary relaxation followed by a rebound contraction. Both responses were abolished by tetrodotoxin, indicating the activation of intramural nonadrenergic noncholinergic nerves. The primary relaxation was totally CTX resistant while the rebound contraction was slightly inhibited. 6. The motor responses produced by capsaicin (1 μM) in the rat or guinea-pig bladder (contraction) and in the rat proximal duodenum (relaxation) were unaffected by CTX. Likewise, the release of substance P-like immunoreactivity from sensory nerves of the guinea-pig bladder muscle was unaffected by CTX. 7. These findings indicate that CTX-sensitive calcium channels modulate transmitter release in autonomic nerve terminals of mammals, but noticeable species and organ related variations exist in sensitivity to this peptide, possibly reflecting the existence of a heterogenous population of voltage-sensitive calcium channels. CTX-sensitive calcium channels are apparently not involved in the excitatory action of capsaicin on sensory nerve terminals.

Human parvovirus infection in haemophiliacs first infused with treated clotting factor concentrates.

Abstract: A group of 27 first infused haemophiliacs was studied for association between heat-treated clotting factor concentrates and transmission of human parvovirus B19. The prevalence rate of B19 antibody, detected by the Immunoelectroosmophoresis (IEOP) reaction, was 55.5% in this group of first infused subjects, significantly higher than the 29.3% of the control group of 58 healthy blood donors but lower than the 93.3% of antibody positive subjects in a group of 30 haemophiliacs multitreated with unheated products. Five of 17 B19 antibody negative patients produced human parvovirus IgM, detectable by radioimmunoassay, after the first treatment with heated concentrates; two of them developed viraemia 6 and 10 days, respectively, after the first infusion dose. These results lead to the conclusion that human parvovirus is transmissible by blood derivatives even when they have been exposed to steam- or dry-heat treatment.

Stability of vector bundles and extremal metrics

Abstract: On donne des exemples de surfaces reglees M qui n'ont pas de champs holomorphes vectoriels non triviaux et qui n'admettent pas de metrique de Kahler extremale dans une classe de Kahler specifique donnee

Simultaneous release by bradykinin of substance P-and calcitonin gene-related peptide immunoreactivities from capsaicin-sensitive structures in guinea-pig heart

Abstract: Both bradykinin and capsaicin infusion evoked a marked increase in the outflow of substance P- (SP-LI) and calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) from guinea-pig isolated, perfused heart After acute exposure to capsaicin in vitro, or in hearts taken from animals pretreated in vivo with capsaicin, bradykinin failed to induce any release The positive chronotropic effect of bradykinin was reduced after acute capsaicin administration The effect of bradykinin in the guinea-pig heart could be mediated, at least partly, by release of neuropeptides from peripheral endings of capsaicin-sensitive sensory neurones

Drainage and Divide Networks Derived from High-Fidelity Digital Terrain Models

Abstract: Through a new contour-specific interpolation algorithm, high fidelity, grid-based, digital terrain models (DTMs) are generated from contour lines digitized by an electronic raster scanner. Starting from DTM data, drainage lines and related divides are automatically identified by means of a set of procedures which also calculates the fundamental geomorphologic and hydrologic parameters of the basin, such as stream-line order, magnitude and length, sub-basin area, perimeter and shape. These techniques find useful application in many fields, ranging from theoretical geomorphology/hydrology to the evaluation of environmental resources and constraints.