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Biomedical subjects

A Pini

Publications and source records attributed to A Pini.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Correlation of IgA class antigliadin and antiendomysial antibodies (IgA-AGA-IgA-EMA) with intestinal histology in celiac disease].

The aim of this work was to establish the diagnostic and follow up value of IgA-class antiendomysium (IgA-EmA) and IgA-class antigliadin (IgA-AGA) antibodies in celiac disease. Correlation with the intestinal histology at the different stages of the disease was evaluated, as well as its therapeutic monitoring ability. Fifty six children, twenty seven girls and twenty nine boys, aged six months to twelve years old, were studied. Thirty nine celiac children were al different diagnostic stages of the disease. Seventeen children with malabsorption symptoms and with normal intestinal histology were used as controls. Sixty blood samples were obtained simultaneously with the small intestinal biopsy. IgA-AGA (ELISA method) and IgA-EmA (immunofluorescent test performed over lower third Rhesus monkey esophagus) were determined in every blood sample. In 34 serum samples from patients with total or subtotal villous atrophy, two were negative for IgA-AGA and only one was negative for IgA-EmA. In 26 samples from patients with normal intestinal histology, two were positive for IgA-AGA and four were positive for IgA-EmA. The results for IgA-EmA had sensitivity 97%, specificity 84.6%, positive predictive value 89.2% and negative predictive value 95%. In the case of IgA-AGA were: sensitivity 94.1%, specificity 92.3%, positive predictive value 94.1%, negative predictive value 92.3%. IgA-AGA and IgA-EmA showed a high correlation with intestinal histology and are in combination powerful tools for the diagnosis and follow up of celiac patients. Besides, they provide a useful aid in the indication of a jejunal biopsy and in close monitoring of the dietary treatment compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies↗
PubMed1992

Epitope mapping of Streptococcus mutans SR protein and human IgG cross-reactive determinants, by using recombinant proteins and synthetic peptides.

alpha-Hemolytic oral streptococci are known to possess a family of cell surface cross-reactive proteins termed Ag I/II, having a molecular mass of approximately 180 to 210 kDa. These proteins are implicated in bacterial adherence to various oral tissues, and we showed recently that the SR protein, an I/II Ag-related protein, from Streptococcus mutans OMZ 175 serogroup f possesses Ag mimicry with human IgG. In this study, regions of the SR protein encoding the cross-reactive epitope(s) were analyzed by expressing selected restriction fragments from the cloned sr gene. The three SR-derived polypeptides reacted in ELISA with anti-SR rabbit IgG, whereas only the two polypeptides located along the carboxyl-terminal two thirds of the SR protein reacted with anti-human IgG rabbit IgG. In order to locate more precisely the human IgG-cross-reactive region, we synthesized six peptides, on the basis of the recently determined complete nucleotide sequence of the sr gene. Among these peptides, peptide 2, corresponding to the alanine-rich repeating amino-terminal region, peptide 3, located in the three tandem proline-rich regions, and peptide 6, located near the cell wall-spanning region, were the most interesting in term of antigenicity and immunogenicity. Anti-peptide 2, 3, and 6 rabbit IgG reacted with free SR and with cell wall-associated SR. Peptide 1, located near the amino terminus, was poorly immunogenic. Peptides 4 and 5, located in the putative human IgG-cross-reactive region, were immunogenic; however, anti-peptide 4 rabbit IgG reacted only weakly with SR or human IgG, whereas anti-peptide 5 rabbit IgG reacted strongly with SR and human IgG, and peptide 5 was recognized by anti-SR and anti-human IgG rabbit IgG. These results confirm the cell surface accessibility of this epitope and its potential participation in eliciting, in rabbits, anti-SR IgG cross-reactive with human IgG.

Amino Acid Sequence↗
PubMed1992

A new bluetongue virus serotype isolated in Kenya.

An apparently new strain of bluetongue virus was first isolated in Kenya in 1965 and since, has been obtained on 7 further occasions from diseased sheep during clinical outbreaks of disease. It proved to be serologically different from the 16 bluetongue virus strains then held at this laboratory. The virus was modified by passage in embryonated hens eggs to produce a live virus strain suitable for inclusion in a polyvalent vaccine. Recent neutralisation tests, carried out with 24 guinea pig immune sera prepared at Pirbright against the currently known World serotypes, have confirmed the earlier results and show that it is different from any of the existing serotypes.

Animals↗
PubMed1991

Anti-IgG antibodies in rheumatic diseases cross-react with Streptococcus mutans SR antigen.

We have previously shown that SR protein, a S. mutans major cell wall protein, as well as the recombinant protein SR (rSR) share common epitopes with human IgG. Since this antigenic mimicry could play a role in the induction of anti IgG, we have examined, in k-ELISA, the presence of antibodies reacting with S. mutans SR proteins and S. mutans whole cells in sera from 36 patients with rheumatic diseases. The majority of the 36 sera showed a high reactivity with rSR when compared with control sera. Eight highly positive sera were further purified on rSR and human IgG sorbents and tested against both rSR and IgG in ELISA and Western blotting. The affinity-purified antibodies reacted strongly with rSR, IgG and IgG Fab fragments but failed to react with IgG Fc fragment. In Western blotting the addition of unlabelled IgG abolished the reactivity of affinity-purified biotinylated antibodies with all antigens, confirming the existence of a common epitope shared by rSR and human IgG heavy chain. We show the existence in rheumatic diseases of high titres of anti-human IgG antibodies cross-reactive with S. mutans SR proteins. Those antibodies are principally IgG and react with the Fd part of the Fab fragment. We can hypothesize from the above data that this antigenic mimicry existing between S. mutans SR-related antigens and human IgG could play a role in the synthesis of at least a part of the anti-IgG antibodies present in rheumatic diseases sera.

Antibodies, Anti-Idiotypic↗
PubMed1990

Purification and partial characterization of rat macrophage Fc receptor and binding factor for IgA.

By using a biotinylated ligand and Western blotting techniques, a receptor (RFc alpha) and a binding factor (BF) for IgA were detected, respectively, on membrane and in the cell-free culture supernatant of rat peritoneal macrophages. Extraction of the RFc alpha was obtained by solubilization of macrophages with Nonidet P-40, and purification was performed by HPLC affinity chromatography on a column derivatized with IgA. RFc alpha is formed of two subunits, with molecular masses of 56 and 70 kDa, which are both involved in the IgA binding ability of rat peritoneal macrophages. IgABF was recovered from the cell-free supernatant of a short-term culture of rat macrophages and was affinity-purified in the same manner as RFc alpha. Like RFc alpha, IgABF retained its IgA binding activity in its native, as well as denatured form. Since the molecular masses of RFc alpha and IgABF are similar, and IgABF competes with RFc alpha for IgA binding, one can assume that IgABF probably represents a shed RFc alpha.

Animals↗
PubMed1990

Complete nucleotide sequence of the sr gene from Streptococcus mutans OMZ 175.

The nucleotide sequence encoding the SR protein of Streptococcus mutans OMZ 175 (serotype f) has been determined. The sr gene consists of 4667 bp and codes for a 171177 Da protein. Comparison of the inferred amino acid sequence with the one of PAc antigen from S. mutans MT 8148 (serotype c) indicates a 88% conservation of amino acid residues which reflects the close relatedness of both proteins. Major differences in amino acid composition are located at the C-terminal part of the sequence where only 298 amino acids of the terminal 420 are conserved.

Amino Acid Sequence↗
PubMed1989

Purification and characterization of the expression product of the sr gene of Streptococcus mutans OMZ 175.

The subcloning in pBR322 of the gene of the S. mutans OMZ 175 74K SR protein, was performed after in vitro reconstitution, from two recombinant EMBL3 phages, lambda SmAD9 and lambda SmAD10. The gene is expressed in E. coli HB101 under the control of its own promoter and produces a protein with a molecular weight of 195 kDa. A strong immunological relationship between the expressed protein and the 74K SR protein was observed in ELISA, Western blotting and immunoprecipitation. The 195 kDa protein was purified by immunoaffinity chromatography to homogeneity as judged by SDS-PAGE and native PAGE. Its reactivity with monoclonal anti 74K SR antibodies indicates that it is probably a precursor form of the 74K SR protein produced in S. mutans. The adhesion properties of the two proteins, tested in solid phase adherence assays, are quite similar. This indicates that the additional peptide present in the precursor protein has little or no role in the adherence properties of protein 74K SR.

Adhesiveness↗
PubMed1988

Neural function: metabolism and actions of inositol metabolites in mammalian brain.

In the nervous system, a variety of cell types respond to external stimuli through the inositol lipid signalling pathways. The stimulus-coupled sequence of intracellular events has been investigated in a homogeneous model system, the cloned mammalian neural cell line NG115-401L. The neural peptide bradykinin stimulates a rapid production of identified inositol phosphate isomers and an intracellular Ca2+ discharge followed by a persistent plasma membrane influx. The temporal sequence suggests that Ins(1,4,5)P3 or Ins(1,3,4,5)P4 or both may coordinate these events in a neuronal cell, as has been suggested in other cell types. Thapsigargin, an irritant and tumour-promoting plant product, produces calcium transients in the absence of inositol phosphate production, and may provide a new tool for investigating the interactions between inositol phosphates and changes in cellular calcium homeostasis. In the 401L line, high levels of radiolabelled InsP5 and InsP6 have been detected, which has led to the evaluation of their possible occurrence and actions in normal brain. Both InsP5 and InsP6 are produced from a radiolabelled myo-inositol precursor in intact mature brain in a region-specific manner. This suggests that both inositol polyphosphates may be end products of regionally regulated biosynthetic pathways. When microinjected into a nucleus of the brainstem, or iontophoretically applied to the dorsal horn of the spinal cord, both InsP5 and InsP6, but not Ins(1,3,4,5)P4 isomers, appear to be potent neural stimulants. These results suggest that the inositol lipid signalling pathways may generate both intracellular and extracellular signals in brain.

Animals↗
PubMed1988

The suitability of a rolled BHK21 monolayer system for the production of vaccines against the SAT types of foot-and-mouth disease virus. I. Adaptation of virus isolates to the system, immunogen yields achieved and assessment of subtype cross reactivity.

In an examination of 34 southern African SAT-type foot-and-mouth disease viruses, all but 1 attained satisfactory levels of infectivity within 6 passages in rolled BHK21 monolayer cell cultures. However, there were marked differences between adapted viruses with respect to the mass of immunogen (146S material) produced. Several isolates which consistently produced levels greater than or equal to 2 micrograms/ml were identified. In cross neutralization tests using post-vaccinal sera, SAT-1 and SAT-2 isolates showed considerable diversity and none of the viruses tested would be expected to produce a broad-spectrum response if incorporated into a vaccine. On the other hand, when 2 of the SAT-2 isolates were incorporated into the same vaccine a distinctly broader response resulted.

Animals↗
PubMed1987

Periodic spasms: an unclassified type of epileptic seizure in childhood.

Seven boys aged between 14 months and 13 years with focal or multifocal partial epilepsy had very unusual seizures, characterized by series of periodic bilateral spasms. These consisted of a brief, complex movement of slight to severe intensity, mainly involving the axial muscles, with raising of the shoulders, adversion of the eyes and head, often with rictus-type facial grimaces and occasional stretching of the legs and emission of a guttural sound. The ictal EEG showed a pattern of periodic complexes, characterized by a slow wave with superimposed fast activity. This form of epileptic seizure is resistant to treatment and is found only in patients affected by a brain disease consisting of a fixed or progressive encephalopathy. These observations document the existence of a rare form of seizure or epileptic event, not yet included in the International Classification of epileptic seizures and clinically relevant because of its diagnostic and prognostic implications.

Adolescent↗
PubMed1986

The effects of locally applied capsaicin on conduction in cutaneous nerves in four mammalian species.

By examination of compound action potentials in the saphenous nerve of the anaesthetized rat it has been shown that capsaicin causes a rapid, dose-dependent, failure of conduction in many C-fibres when applied directly to the nerve. A large reduction in C-fibre conduction occurs with concentrations as low as 110 microM. After a 15-30 min exposure to capsaicin, only partial recovery occurs in 1 h. Similar block of C-fibre conduction occurs in the ferret. However, only smaller, reversible, reductions in C-fibre conduction were seen in the guinea-pig and rabbit, even at the highest concentration of capsaicin used (33 mM). A small reduction in the A delta component of the compound action potential occurred in all four species. In the rat and ferret the effects were much less than those on C-fibres. At high doses, small reversible effects were also seen on the fastest conducting A alpha beta component of the compound action potential in the rat, rabbit and guinea-pig; no effects were seen on the A alpha beta fibres in the ferret. Decreases in amplitude of the compound action potential were accompanied by some slowing of conduction in most cases. The slowing was less than 5% except for the rat A alpha beta and C-fibres and the ferret C-fibres where 9-15% changes occurred at the highest doses of capsaicin. Opening the connective tissue sheath of the nerve did not significantly increase the effectiveness of capsaicin.

Action Potentials↗
PubMed1986

Foot-and-mouth disease and the African buffalo (Syncerus caffer). 1. Carriers as a source of infection for cattle.

Ten pregnant buffalo cows, six of which were subsequently shown to be carriers of SAT 1, 2 and 3 viruses, were captured in the Kruger National Park (KNP) and allowed to calve in captivity. The buffalo cows and calves were separated by a fence from 6 FMD susceptible cattle but the buffalo and cattle were obliged to use common drinking troughs and hay racks. Over a period of 15 months, during which the buffalo calves lost their maternally-derived immunity, neither the buffalo calves nor the susceptible cattle became infected with FMD virus. By the end of the observation period, however, only 1 buffalo cow still had detectable virus in its oesophageal/pharyngeal specimens.

Animals↗
PubMed1986

Foot-and-mouth disease and the African buffalo (Syncerus caffer). II. Virus excretion and transmission during acute infection.

Three groups of young buffalo in captivity were infected by exposing them to similar buffalo in the acute stages of infection induced by needle inoculation with SAT 1 or 2 viruses. Clear foot lesions developed in most of the buffalo from which the relevant virus types were re-isolated. During the first week following infection virus was found in blood, nasal secretions, saliva, preputial secretions and faeces. Air samples collected in the immediate vicinity of acutely infected buffalo were also found to contain virus. However, the regularity of virus detection as well as the quantity of virus in buffalo specimens was generally lower than for cattle infected with viruses of the same type. Conversely, virus was detected in the nasal secretions or saliva of 3 buffalo up to 4 weeks after infection, a situation which has not been encountered in cattle. Susceptible cattle and impala (Aepyceros melampus) were penned together with or in the immediate vicinity of infected buffalo and shared feeding and watering facilities with the buffalo. The pattern of transmission which emerged indicated that transfer of these viruses from buffalo to other species probably occurs only in the acute stages of infection and where there is direct physical contact between the species.

Air Microbiology↗
PubMed1983

Drug addiction during pregnancy.

On the basis of current literature and their own experience, the authors discuss (1) the major complications possible in pregnant drug addicts, (2) whether the complications can be attributed to deficient prenatal care or to effects of drug abuse, and (3) the best prenatal care of drug-addicted mothers.

Birth Weight↗
PubMed1977

Negative staining of a non-haemadsorbing strain of African swine fever virus.

Since the application of negative staining, preceded by fixation, prevents the disruption and distortion of the capsid of the African swine fever virus, improved contrast and evaluation of the appearance and size of virus particles in the electron microscope is possible and, in addition, the icosahedral shape of the virus is demonstrable. The mature virus particle contains at least 2 capsid layers and an outer envelope.

African Swine Fever Virus↗
PubMed1976

Study on the pathogenesis of bluetongue: replication of the virus in the organs of infected sheep.

The pathogenesis of bluetongue infection was studied by the titration of the virus in tissue samples taken from sheep inoculated subcutaneously in the auricula of the ear with 76 TC ID50 of the plaque-purified type 10 bluetongue virus. Tissue samples were taken from individual animals killed at daily intervals over a period of 11 days. The mean incubation time was 6.9 days and the first clinical sign was pyrexia. On the 4th day, bluetongue virus was demonstrated in the lymph nodes of the cephalic area, tonsils and spleen; viraemia became demonstrable on the 6th day post-inoculation and typical macroscopic lesions due to the virus were first observed on the 8th day. It was concluded that, post-infection, the virus entered the regional lymph nodes. From there it was disseminated via the lymph and/or the blood stream to the lymphoid tissues in other parts of the body where further replication occurred. From these primary sites the virus was carried via the blood stream and infected the majority of tissues. Humoral antibody, as detected by immunofluorescence, did not appear to have a direct influence on the concentration of virus in solid tissues. Persistence of the virus in infected sheep was not demonstrated when tissues were taken 6, 8 and 16 weeks after infection.

Animals↗
PubMed1975

Porcine parvovirus in pig herds in Southern Africa.

Evidence of the presence of porcine parvovirus in Southern Africa is given and the diagnostic significance of this finding is discussed. Minor abnormalities in the replication of the virus were observed.

Animals↗