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Biomedical subjects

G Grimaldi

Publications and source records attributed to G Grimaldi.

At least 91 records · Page 5Linked to original sources
PubMed1984

Production and characterization of species-specific monoclonal antibodies against Leishmania donovani for immunodiagnosis.

Sixteen species-specific monoclonal antibodies were produced against membranes of Leishmania donovani. These antibodies only reacted with determinants present on L. donovani. No cross-reactions were found with any other species of Leishmania or with membranes of Trypanosoma cruzi. An extensive analysis of the binding specificities of selected antibodies was carried out by using whole promastigote homogenates as antigen. Monoclonal antibodies D-1, D-2, D-3, and D-4 correctly identified all 44 L. donovani stocks from a cross-panel of 84 New and Old World Leishmania stocks. Antibodies D-1 and D-2 were also useful for species classification by immunofluorescence. No cross-reactions were observed with any other Leishmania species examined. Based on either Western blot and/or radioimmunoprecipitation analyses, five distinct groups of molecules associated with L. donovani-specific antigenic determinants were identified. These molecules range in m.w. from 18 to 84 kilodaltons. The antigenic molecules recognized by antibodies D-2, D-10, and D-13 are also recognized by antibodies present in sera from patients with visceral leishmaniasis (kala-azar). Kala-azar sera obtained from cases in both the Old and New World specifically compete with these monoclonal antibodies for the appropriate antigenic determinants in Western blot analysis. These monoclonal antibodies and/or the purified protein antigens may be useful in the development of a serologic assay for the clinical diagnosis of visceral leishmaniasis caused by L. donovani and in epidemiologic studies of leishmaniasis.

Animals↗
PubMed1984

Evidence for the involvement of arachidonic acid metabolites in spontaneous and drug-induced contractions of rat urinary bladder.

The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and endogenous arachidonic acid (AA) depletion on spontaneous and drug-induced contractions of the rat urinary bladder have been determined by both in vivo and in vitro experiments. Our results suggest that some AA metabolites (presumably prostaglandins) are involved in the physiologic regulation of the micturition reflex in the rat. In vivo findings indicate that the ability of various NSAIDs to inhibit distension-induced rhythmic contractions is proportional to their anti-inflammatory effectiveness. NSAIDs administration or depletion of endogenous AA at the detrusor muscle level by essential fatty acid-free diet (EFAFD) decreased the responsiveness of the urinary bladder to reflex activation. Topical AA triggered a series of neurogenic rhythmic contractions in the preparation which failed to respond to saline loading. This effect was prevented by NSAID pretreatment. The effect of topical AA was mimicked in NSAID-treated preparations by topical prostaglandins. Both NSAIDs and EFAFD reduced the responsiveness of the rat urinary bladder to acetylcholine and purinergic stimulation in vivo and in vitro. NSAIDs enhanced, while EFAFD reduced, the responsiveness of the isolated bladder to stable cholinomimetics. Responsiveness to KCl was unaffected by NSAIDs or EFAFD. These latter findings indicate that either blockade of AA metabolism along the cyclooxygenase pathway or endogenous AA depletion might alter bladder responsiveness at the postjunctional level. However, because the amplitude of distension-induced rhythmic contractions is unaffected by NSAIDs or EFAFD, it appears unlikely that endogenous prostanoids play a role in excitatory neurotransmission or in tension development during physiological-like activation of the bladder muscle. In vitro findings indicate that both NSAIDs and EFAFD reduce the myogenic contractility and the responsiveness to stretch of bladder muscle. These findings are suggestive that AA metabolites could regulate micturition by enhancing the amplitude of the myogenic contractions of the bladder muscle and, consequently, the discharge of vesical afferents to the central nervous system.

Adenosine Diphosphate↗
PubMed1983

Homology between the KpnI primate and BamH1 (M1F-1) rodent families of long interspersed repeated sequences.

The KpnI and BamH1 (or M1F-1) families are the predominant sets of long interspersed repeated DNA sequences (LINEs) in primates and rodents, respectively. Recently, the sequences of several cloned subsegments from each family were determined in different laboratories. These sequences have now been compared and found to be homologous over at least 1400 bp. The data suggest that the two LINE families had a common progenitor and have been conserved in similar abundance although in divergent forms in the two mammalian orders.

Animals↗
PubMed1983

Members of the KpnI family of long interspersed repeated sequences join and interrupt alpha-satellite in the monkey genome.

Three different members of a family (KpnI-family) of interspersed repeated DNA sequences were found linked to alpha-satellite sequences in cloned segments of the African green monkey genome. In two of these segments the KpnI-family member is over 6 kbp in length and one of them is flanked by alpha-satellite on both sides indicating that it was inserted into a satellite array. Hybridization of subcloned portions of the family members to restriction endonuclease digests of monkey and human DNA and to a genomic library of African green monkey DNA indicate that 1) family members are interspersed in both the monkey and human genomes, 2) some family members may include sequences in addition to those in the three characterized here, 3) some family members may contain only parts of the sequences characterized here and 4) while the overall organization of the family is similar in the human and monkey genome the majority of the family members in each of the two genomes are distinctly identified by the variant position of certain restriction endonuclease sites. This last observation suggests that within each genome there is a tendency to maintain particular versions of the sequence. Observations 2) and 3) suggest that the KpnI family is complex and includes a variety of subfamilies.

Animals↗
PubMed1983

The effect of peripherally administered GABA on spontaneous contractions of rat urinary bladder in vivo.

Intravenous GABA suppresses the spontaneous contractions of rat urinary bladder produced by saline loading (micturition reflex) without possessing any significant inhibitory effect on spontaneous and stimulated (neuro-hormones and field stimulation) contraction of rat detrusor strips in vitro. The in vivo effects of GABA, in view of the results obtained with atropine, hexamethonium and tetrodotoxin in the same experimental conditions, are likely to be ascribable to an action at pelvic ganglia level.

Animals↗
PubMed1983

Beta-adrenoreceptor blockers and CaCl2-induced arrhythmias in the rat: discrepancies between antiarrhythmic properties and survival rate.

Although propranolol antagonized CaCl2-induced arrhythmias in the rat due to its local anaesthetic properties, arrhythmias-protected animals died because of respiratory failure. To assess the relative role played by beta 2-adrenoreceptor blocking and local anaesthetic properties in the genesis of this phenomenon, five beta-blockers with different degrees of local anaesthetic properties have been tested at their respective ED50 against CaCl2-induced arrhythmias in the rat and their respective surviving/arrhythmias-protected animals ratio (SAPAR) calculated. A highly significant correlation exists between local anaesthetic properties and SAPAR but not between SAPAR and beta 2-adrenoreceptor blocking properties. Further studies showed that (a) assisted ventilation but not picrotoxin or terbutaline pretreatment protected rats against propranolol-CaCl2-induced respiratory failure, and (b) intracerebroventricular propranolol failed to antagonize CaCl2-induced arrhythmias while producing a dose-dependent inhibition of breathing rate. These results suggest that, in this test model, local anaesthetic properties of beta-blockers are responsible for their antiarrhythmic effect at peripheral level, and superimpose to the effects of CaCl2 in inducing respiratory failure at central level.

Adrenergic beta-Antagonists↗
PubMed1983

The effects of nifedipine and verapamil on high K+ induced contractions of the rat intestinal tract in vivo.

The effects of intravenous nifedipine and verapamil against the contraction produced by topical application of 54 mM K+ on the outer surface of rat duodenum, jejunum, ileum, caecum, colon and rectum have been investigated. Both drugs exhibited a descending gradient of relaxant activity with the exception of the rectum, verapamil being 1/3-1/4 as potent as nifedipine in all the test systems studied. Since these drugs at effective spasmolytic doses significantly affect heart rate and systemic blood pressure, their use as smooth muscle relaxants in intestinal disturbances would present several drawbacks.

Animals↗
PubMed1982

A monkey Alu sequence is flanked by 13-base pair direct repeats by an interrupted alpha-satellite DNA sequence.

A member of the Alu family, the dominant family of short interspersed repeated DNA sequences in primates, interrupts a cloned repeat unit of African green monkey alpha-satellite DNA. The Alu is immediately flanked by 13-base-pair duplications of the known sequence of the satellite at the site of insertion. These observations support the idea that Ala family members may be moveable elements.

Animals↗
PubMed1982

Pregnancy after autografting and allografting vascularized ovaries and en bloc vascularized ovaries with adnexa in rabbits.

Initially, techniques for autografting ovaries with or without adnexa were developed but a 30% vascular failure rate was experienced by day 14. Of the technically successful grafts, 50% proved fertile. Single vascularized ovaries with their oviducts were then allografted into bilaterally ovariectomized rabbits by microsurgical techniques and the vascular failure rate was reduced to 5% of 40 grafts. The time-course of rejection in untreated recipients was mapped by histological examination and by 24-h culture of fallopian tubes after autopsy at different times after transplantation. Control allografts were consistently rejected by day 20. Striking prolongation of both types of graft was obtained with a short 17-day course of cyclosporin A at 10 or 15 mg day-1 kg-1. Indeed, significant evidence of rejection was found in only two ovaries out of 20 so far examined histologically. Mating behaviour, ovulation, ciliary function and transport of ova appeared normal in 80% of the recipients as long as 18 weeks after stopping cyclosporin A treatment. Only one of the ovarian allografted rabbits has so far been mated and this produced seven normal young 126 days after transplantation. However, none of the five animals mated after being allografted with en bloc adnexa have so far become pregnant.

Adnexa Uteri↗
PubMed1982

Age-related protective role of parasympathetic nervous system against hypercalcaemia-induced ventricular arrhythmias in the rat.

Time of appearance of extrasystoles, ventricular fibrillation, and cardiac arrest were monitored in urethane-anaesthetized rats of different ages following CaCl2 infusion. Ca++ required to produce ventricular arrhythmias was significantly higher in younger than in older animals. Bilateral vagotomy or atropine treatment significantly reduced Ca++ requirements for production of arrhythmias in younger but not in older animals. These findings support the hypothesis of vagally mediated age-related antagonism toward Ca++-induced ventricular arrhythmias. This suggests that young subjects are less prone to develop ventricular rhythm disturbances as a result of hypercalcaemic states.

Age Factors↗
PubMed1982

Intralesional plasma cells and serological responses in human cutaneous leishmaniasis.

Intralesional plasma cells and serological responses were investigated in 20 Brazilian cases of cutaneous leishmaniasis. Plasma cell numbers varied from less than 10% to more than 50% of cells in inflammatory infiltrates, in general with greater numbers of such cells present in lesions of longer duration. Direct fluorescence examination with anti-IgG, -IgA and -IgM sera of trypsin-treated sections of formalin-fixed biopsy tissue revealed that most intralesional plasma cells contained IgG. Russell bodies were detected in eight cases, in seven of which these bodies fluoresced only with anti-IgM serum. There was no correlation between serum levels of total IgG, IgA and IgM (detected by radial immunodiffusion) or antileishmanial antibodies (detected by class-specific indirect immunofluorescence and by direct agglutination with and without 2-mercaptoethanol) and numbers of intralesional plasma cells of the same globulin class. No striking or consistent alterations in complement components were noted in the serum of these patients.

Cell Count↗
PubMed1982

The effects of nifedipine and verapamil on spontaneous and carbachol-stimulated contractions of rat urinary bladder "in vivo".

The effects of nifedipine and verapamil on spontaneous and carbachol-induced contractions of rat urinary bladder have been studied after intravenous administration. Both nifedipine and verapamil delayed the onset of spontaneous contractions in a dose-dependent manner, but nifedipine on the contrary of verapamil only slightly antagonized the intensity of spontaneous contractions and of carbachol contracture. These results suggest that the effects of verapamil on rat urinary bladder "in vivo" are different from those of nifedipine.

Animals↗
PubMed1981

Interspersed repeated sequences in the African green monkey genome that are homologous to the human Alu family.

The dominant family of interspersed repetitive DNA sequences in the human genome has been termed the Alu family. We have found that more than 75% of the lambda phage in a recombinant library representing an African green monkey genome hybridize with a human Alu sequence under stringent conditions. A group of clones selected from the monkey library with probes other than the Alu sequence were analyzed for the presence and distribution of Alu family sequences. The analyses confirm the abundance of Alu sequences and demonstrate that more than one repeat unit is present in some phages. In the clones studied, the Alu units are separated by an average of 8 kilobase pairs of unrelated sequences. The nucleotide sequence of one monkey Alu sequence is reported and shown to resemble the human Alu sequences closely. Hence, the sequence, dispersion pattern, and copy number of the Alu family members are very similar in the African green monkey and human genomes. Among the clones investigated were two that contain segments of the satellite DNA term alpha-component joined to non alpha-component DNA. The experiments indicate that in the monkey genome Alu sequences can occur close to regions of alpha-component DNA.

Animals↗