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Biomedical subjects

A Leonardi

Publications and source records attributed to A Leonardi.

At least 19 recordsLinked to original sources
PubMed1992

Conjunctival mast cells and the allergic late phase reaction.

An active model of ocular anaphylaxis was developed in guinea pigs to evaluate the histopathology of the early (EPR) and late (LPR) phase reaction, focusing on the role of mast cells. Five groups (n = 6) of animals were actively immunized by first injecting into each of the axillary and inguinal lymph node areas, 0.25 ml of an emulsion containing 1 mg dinitrophenyl bovine gamma-globulin (DNP-BCG) with 0.5 ml complete Freund's adjuvant. After two weeks, an intramuscular injection of 0.5 ml of an emulsion containing 1 mg DNP-BGG with 0.5 ml of incomplete adjuvant was administered. One month after the first injection, animals were sacrificed after topical ocular challenge with 10 microliters of 1 mg/ml divalent hapten, di-DNP-lysine, in one eye and phosphate buffered saline (PBS) in the fellow eye as control. Clinical reactions were graded over time and histology evaluated at the endpoint (time 0, 0.5, 3, 9, and 24 h). Results showed that all animals clearly developed both an EPR and an LPR, as either a biphasic, multiphasic or prolonged clinical response. A small percentage of mast cells were degranulated at baseline, whereas, at 0.5 h, 95% of mast cells were degranulated in the eyes treated with specific hapten and 25% in the control eyes treated with PBS. At 3 h, 84% of the mast cells were degranulated. This value rose to 89% at 9 h, and remained unchanged at 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Calcium interaction with bovine thyroglobulin: stoichiometry and structural consequences of calcium binding.

Gel filtration studies show that the thyroglobulin (Tg) molecule (dimer) binds from 18 to 50 Ca2+ ions. At pH 7.5 Tg binds 18 Ca2+ ions with a Kd of 1.3 x 10(-5) M, and 50 Ca2+ ions with a Kd of 5.5 x 10(-4) M. The binding of calcium to bovine thyroglobulin increases the absorption band of iodoamino acid residues at 315 nm. In the presence of Ca2+, the fluorescence intensity of 1-anilino-8-naphthalene sulfonate (ANS) is increased about 5-fold by Tg, with a shift in the fluorescence emission maximum from 505 to 490 nm. Thus, thyroglobulin possesses two classes of calcium binding sites with different affinities. The data reported indicate, also, that Ca2+ binding to Tg increases the hydrophobicity of the surface of the molecule.

Anilino Naphthalenesulfonates↗
PubMed1991

Double hapten challenge in guinea pigs undergoing an ocular late-phase reaction.

Clinical and histological profiles of guinea pig conjunctiva undergoing late-phase reaction (LPR) were evaluated before and after additional antigenic challenge. Four groups of animals were passively sensitized with IgG1 antibodies, challenged with the specific hapten di-DNP-lysine, and rechallenged during LPR either with di-DNP-lysine, or with PBS, or with an aspecific antigen to characterize the reactivity of the inflamed conjunctival tissues. The course of the clinical anaphylactic responses was modified slightly only by challenge with a specific hapten during LPR. However, no significant changes in the inflammatory cell profile were observed in conjunctiva undergoing LPR after an additional challenge. This suggests the participation of mechanisms which may mediate the attenuation of the anaphylactic response in physiologic conditions of persistent antigen provocation.

Anaphylaxis↗
PubMed1991

Defects in diagnostic kits for determination of urate in serum.

Certain diagnostic kits that measure serum urate by the Barham and Trinder principle of enzymic liberation of oxygen and its combination with chromogens can give results for urate in fresh serum that are approximately 20% lower than results from serum stored at ambient temperature for 72 h. In fresh serum, antioxidants compete with chromogen for liberated peroxyl-oxygen. We postulate that during storage the interfering antioxidant substances are destroyed. In some diagnostic kits, L-ascorbate oxidase is added to the reaction, eliminating some but not all of this effect. We discuss defects of several commercially available kits for determination of serum urate and recommend comparing results of these kits with results from the phosphotungstic acid method as a precaution against falsely low results.

Blood Preservation↗
PubMed1990

Topical use of cyclosporine in the treatment of vernal keratoconjunctivitis.

We treated 11 patients with vernal keratoconjunctivitis for four to nine months with topical cyclosporine as a 2% dilution in castor oil. No significant side effects occurred, except for mild and transient burning upon administration. Within the first 15 days, both symptoms and signs of the condition improved significantly, and these results were maintained throughout the entire treatment. Relapses of the disease occurred two to four months after the end of the therapy. A double-masked clinical trial of nine patients (2% cyclosporine in castor oil vs castor oil alone) confirmed the results. Treated eyes improved significantly for both signs and symptoms as compared to control eyes. Topical cyclosporine may, therefore, be considered an effective substitute for corticosteroids, with an excellent anti-inflammatory activity in patients with both corticosteroid-dependent and corticosteroid-resistant vernal keratoconjunctivitis.

Administration, Topical↗
PubMed1990

Blood coagulation factors in human embryonic-fetal development: preferential expression of the FVII/tissue factor pathway.

The expression of a number of blood coagulation factors (F) (FX, FIX, FVIII, FVII, alpha-, beta-, gamma-fibrinogen chains, protein C, and antithrombin III [AT III]) was analyzed at RNA and protein level in 5- to 10-week-old human embryos and fetuses. FX, FIX, and FVII were also analyzed at protein level. Total and poly(A)+ RNA, extracted from embryonic-fetal (FL) and adult liver (AL), were analyzed by dot and Northern blot hybridization with specific cDNA probes. The results indicate that: (1) the size of the messenger RNAs of these factors is equivalent in FL and AL; (2) in the 5- to 10-week period, their abundance in FL increases from 30% to 50% of the adult level except for FIX (from 2% to 10%) and FX (always 100% of the adult value). Western blot analysis of FIX, FX, and FVII in 5- to 10-week soluble liver proteins and 6- to 8-week plasma showed a low level of FIX versus a higher concentration of both FVII and FX, when compared with corresponding adult values, ie, a liver protein level of 10% versus 100% and a plasma concentration level of 10% versus 40%. Although little is known so far on the activity and the functional role of the clotting factors in early human ontogenic development, these studies suggest an activation of FX via the FVII/tissue factor activity rather than the FIXa/FVIIIa phospholipid complex in human embryonic and early fetal life.

Blood Coagulation Factors↗
PubMed1990

Late onset globoid leukodystrophy: unusual clinical and CSF findings.

During a febrile upper respiratory tract illness this 4 year old boy developed left hemiparesis, which progressed to loss of walking and even of sitting finally to tetraplegia. The cerebrospinal fluid protein pattern showed blood-brain barrier damage with additional intrathecal IgG synthesis. The symptoms responded to steroid therapy but resumed and worsened on withdrawal. Only late, when visual evoked potentials and nerve conduction velocity proved to be impaired, was Krabbe disease diagnosed on the assay of cultured fibroblasts for galactocerebroside-beta-galactosidase. We discuss the significance of possible endogenous production of IgG in the CNS.

Child, Preschool↗
PubMed1990

Correlation between conjunctival provocation test (CPT) and systemic allergometric tests in allergic conjunctivitis.

In order to assess the potential usefulness of CPT as a diagnostic tool for ocular allergy, the correlation between skin/RAST tests and CPT was determined in 144 patients affected by allergic 'hay fever' type conjunctivitis. The results showed that an agreement between skin/RAST tests and CPT occurred in 71% of the cases (130/183). Of the 29% uncorrelated cases, 23% (43/183) were positive for at least one specific antigen by skin/RAST tests but not by CPT, while 6% (10/183) were positive for at least one specific antigen by CPT, but not by skin/RAST tests. CPT dramatically increased the histamine levels in tears (p less than 0.001). These findings show that (1) systemic tests can be misleading in that they may suggest a specific sensitisation which, in fact, does not involve the conjunctiva (systemic test positive/CPT negative); (2) CPT can identify local conjunctival sensitisation in the absence of a systemic sensitisation (systemic test negative/CPT positive); (3) CPT can demonstrate that allergic 'hay fever' type conjunctivitis may be related to allergens different from those responsible for a systemic sensitisation.

Adolescent↗
PubMed1990

Clinical patterns of ocular anaphylaxis in guinea pigs passively sensitized with IgG1 antibody.

A model of topically induced ocular anaphylaxis in guinea pigs was developed. A guinea pig anti-dinitrophenyl (DNP) bovine gamma-globulin antiserum rich in IgG1 antibodies was injected subconjunctivally; various serum dilutions and latent periods were tested. The anaphylactic response was elicited with di-DNP-lysine applied topically. The response was characterized by rating 11 ocular signs. Although the 4-hour latent period is considered optimal for passive cutaneous anaphylaxis, a 14-hour latent period yielded the strongest ocular reaction and appeared to the most appropriate time for clinical assessment. Both an early-phase reaction (peaking in the 21st hour) and a late-phase reaction (peaking at 6-10 h) were observed. The two signs of the early-phase reaction that recurred in the late-phase reaction were periorbital swelling and lid redness. The anaphylactic reaction displayed different patterns in different animals: protracted, biphasic and multiphasic.

Anaphylaxis↗
PubMed1990

Histology of ocular late-phase reaction in guinea pigs passively sensitized with IgG1 antibodies.

The ocular late-phase reaction (LPR) is a mast cell-dependent, delayed inflammatory reaction developing 4-12 h after the early-phase reaction (EPR). We developed a passive IgG1 antibody-dependent guinea pig model that clinically reproduced the biphasic reaction of ocular EPR and LPR. An EPR was observed in all animals; a biphasic, multiphasic or prolonged inflammation was observed in the animals maintained for 9 and 24 h. The substantia propria of eyes undergoing EPR (0.5 h) showed intense edema, mast cell degranulation (88%), and 4-fold increase in eosinophils. At 9 h, the neutrophils and eosinophils had increased 11- and 25-fold, respectively. The number of basophils and lymphocytes was significantly increased compared to the controls (p less than 0.05). Of the mast cells, 45% were degranulated compared with 19% for controls. Cellular reactions had subsided by 24 h. Conjunctival epithelium also accumulated inflammatory cells as did the stroma of the lid skin. These histologic changes in ocular tissues undergoing anaphylaxis demonstrated that mast cell degranulation was most severe in the early phase, whereas neutrophil, eosinophil, and basophil accumulation was most marked in the late phase.

Animals↗
PubMed1989

[Results of the initial 50 heart transplantations in Zurich].

During the first 40 months of the new Heart Transplantation Program (September 1985 until December 1988) a total of a 160 patients were evaluated for transplantation at the University Hospital in Zurich. 50 patients eventually came to heart transplantation, while one patient underwent a heart-lung transplant. In the same period 9 patients accepted for transplantation died on the waiting list before transplantation. All 50 hearts were transplanted orthotopically. Follow-up treatment, immunosuppression and diagnostics for rejection are described. There was no operative mortality in this group. Two patients died early and three died late. For the first consecutive 50 heart transplant patients, showing a total of 732 patient months, actuarial survival was calculated at 90.1% at one and two years, and at 79.5% at three years. "Enlarged Heart Transplantation Program" describes some of the secondary activities spurred by the new Heart Transplantation Program.

Actuarial Analysis↗
PubMed1989

Functional study of T lymphocyte responsiveness in patients with dementia of the Alzheimer type.

The autologous mixed lymphocyte reaction (AMLR) was used to study T lymphocytes in a group of patients with dementia of the Alzheimer type (DAT) in order to confirm the observation that their T cell proliferation in AMLR was greater than in age-matched controls, and to investigate other pathways of T cell activation, searching for correlations between immunologic and clinical findings in DAT. The mean proliferative response in AMLR was increased in patients with DAT. No differences between patients and age-matched controls were detected when other pathways of T cell activation were investigated. The degree of response in the AMLR varied among patients with DAT. This fits with the suggestion that the disorder may be a heterogeneous syndrome.

Aged↗
PubMed1989

IgG paraproteinemias: a comparative CSF and serum study.

In 10 neurologic patients routine isoelectric focusing of CSF and serum revealed monoclonal IgG paraproteinemia (3 multiple myelomas and 7 benign monoclonal gammopathies). Quantitative protein study showed blood-brain barrier damage in 7 out of 10 patients; 2 patients had intrathecal synthesis of IgG measurable by Reiber's formula. Each case showed identical monoclonal IgG pattern in CSF and serum at isoelectric focusing and immunofixation. We suppose that monoclonal IgG detectable in the CSF usually derive from the serum across the intact or damaged barrier. The occurrence of quantifiable intrathecally synthesized IgG in 2 patients, both with skeletal lesions close to the subarachnoid spaces, and the identical patterns of IgG in CSF and serum suggest that tumoral plasma cells secrete monoclonal IgG into blood and CSF from the bone location.

Aged↗
PubMed1989

Synthesis and anticonvulsant evaluation of 1,2-diphenylethane derivatives, potential metabolites of denzimol.

A number of new 1,2-diphenylethane derivatives were synthesized and tested for anticonvulsant activity. Their structure was designed on the basis of the potential metabolic degradation of the imidazole ring present in denzimol ( ( +/- )-N-[2-[4-(beta-phenylethyl)phenyl]-2-hydroxethyl]imidazole), a potent anticonvulsant. The compounds which inhibited the electroshock-induced seizures (MES) in mice, namely N-[4-(beta-phenylethyl)phenacyl]formamide (VII) and N-[2-[4-(beta-phenylethyl)phenyl]-2-hydroxyethyl]formamide (IX), proved active also as inhibitors of the pentylenetetrazole-induced tonic seizures. The results of the pharmacological screening were evaluated in relation to the lipophilicity of the compounds.

Animals↗
PubMed1989

[Results of a questionnaire on malignant tumors of the oral cavity].

A set of 23 questions on malignant neoplasms of oral cavity has been submitted to a group of 38 graduate in dentistry and dental prosthesis, at the time of their qualifying examination. The answers reveal a sufficient degree of knowledge of the problem but also indicate that some specific aspects of this important question should be probed.

Education, Dental, Continuing↗
PubMed1988

Genetic aspects of variation of protein amounts in maize and pea.

Using high-resolution two-dimensional polyacrylamide gel electrophoresis we studied the polymorphism of protein amounts in some genotypes of maize and pea. This type of variability seems to be rather common and insensitive to environmental conditions, as attested by the comparison of the patterns of two maize lines harvested in two different years. A large-scale experiment involving 5 lines, 7 of their hybrids, and 6 organs (or physiological stages) of maize allowed us to examine numerous polypeptides regarding their genetic variability, their amount differences between organs and the inheritance of their abundance. Genetic and organ variations are not independent: polypeptides whose amount varies from one organ to another are, for the most part, genetically variable (59%), while the stable polypeptides are not often genetically variable (18%). We found a striking organ specificity for (i) the extent of quantitative variability (from 2.3-15.4% of the polypeptides), (ii) the occurrence and the type of variation for a given polypeptide (an intensity difference seen in an organ can disappear or even be reversed in another one), (iii) the kind of inheritance (additive/non-additive): combining the 6 organs and the 7 hybrids we found 101 cases of non-additivity (4% of the total) which concern as many as 72 different spots, that is to say that in most cases a polypeptide displaying nonadditivity in an organ seems to display additivity in the other ones. Moreover, for most of the polypeptides with nonadditive inheritance the hybrid spot presents an intensity similar to that of the most intense parental spot.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophoresis, Gel, Two-Dimensional↗
PubMed1988

Oligoclonal and polyclonal synthesis of IgG in the central nervous system: an isoelectric focusing study.

The IgG pattern in isoelectric focusing (IEF) has been studied in 90 paired samples of cerebrospinal fluid (CSF) and sera obtained from patients in which intrathecal synthesis of IgG without barrier damage was detectable by Reiber's graph and formula (1980, J. Neurol. 224, 89). Thirty patients were affected by multiple sclerosis (MS), 30 by other inflammatory nervous diseases (OID), and 30 by noninflammatory nervous diseases (NID). At IEF two distinct pathological patterns of CSF IgG were detected: oligoclonal bands (OB), prevailing in the MS group (83% of cases), and a "polyclonal"--i.e., diffuse, uniform--increase of CSF IgG, prevailing in the NID (90%). The OID group was intermediate, 57% of cases with OB and 43% with polyclonal CSF IgG patterns. Overall, only 45 of 90 patients synthesizing IgG in the CNS had CSF OB. This suggests that the CNS immune response can imply either the synthesis of IgG of restricted heterogeneity (i.e., OB) or a polyclonal IgG synthesis, giving in IEF a serum-like pattern to the CSF.

Central Nervous System↗