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Biomedical subjects

P Belli

Publications and source records attributed to P Belli.

At least 19 recordsLinked to original sources
PubMed1999

Natural and experimental oral infection of nonhuman primates by bovine spongiform encephalopathy agents.

Experimental lemurs either were infected orally with the agent of bovine spongiform encephalopathy (BSE) or were maintained as uninfected control animals. Immunohistochemical examination for proteinase-resistant protein (prion protein or PrP) was performed on tissues from two infected but still asymptomatic lemurs, killed 5 months after infection, and from three uninfected control lemurs. Control tissues showed no staining, whereas PrP was detected in the infected animals in tonsil, gastrointestinal tract and associated lymphatic tissues, and spleen. In addition, PrP was detected in ventral and dorsal roots of the cervical spinal cord, and within the spinal cord PrP could be traced in nerve tracts as far as the cerebral cortex. Similar patterns of PrP immunoreactivity were seen in two symptomatic and 18 apparently healthy lemurs in three different French primate centers, all of which had been fed diets supplemented with a beef protein product manufactured by a British company that has since ceased to include beef in its veterinary nutritional products. This study of BSE-infected lemurs early in their incubation period extends previous pathogenesis studies of the distribution of infectivity and PrP in natural and experimental scrapie. The similarity of neuropathology and PrP immunostaining patterns in experimentally infected animals to those observed in both symptomatic and asymptomatic animals in primate centers suggests that BSE contamination of zoo animals may have been more widespread than is generally appreciated.

Animals↗
PubMed1998

Detection of bovine immunodeficiency-like virus infection in experimentally infected calves.

Detection of BIV virus infection by serological means, PCR and virus isolation in experimentally infected calves is described. Viral sequences were specifically detected by PCR in peripheral blood mononuclear cells (PBMCs), with primer systems located in the gag, pol and tat regions of the viral genome. An enzyme-linked oligosorbent assay (ELOSA) in microtiter plates is described, for the detection of PCR products, the sensitivity of which was shown to be comparable to that of membrane hybridization detection. Serological response of the animals against the BIV p26 protein was shown, using a recombinant fusion protein ((His)6p26) expressed in E. coli and purified by metal affinity chromatography, in ELISA and Western blot studies. The presence of infectious virus was demonstrated by its rescue, by virus isolation in cell cultures, from PBMCs during a one year follow-up.

Animals↗
PubMed1998

Sensitivity of the Western blot detection of prion protein PrPres in natural sheep scrapie.

The sensitivity of Western blot detection of PrPres using two different extraction procedures on brain material of 30 scrapie-affected sheep was compared. Whereas PrPres could be detected in all sheep after extraction with the first method, 30% did not give any signal after extraction with the second method. However, the second method, when positive, permitted the detection of PrPres from smaller amounts of infected brain tissue. When used with the ruminant specific monoclonal antibody p4, the second method gave positive signals corresponding to less than 12.5 microg of scrapie-infected brain, that, up to now, is the highest sensitivity described for PrPres detection from naturally infected ruminant brains. The overall results showed highly variable levels of PrPres between sheep and are presented in relation to breed, survival time and animal genotype data. Further progress can thus be expected for PrPres detection in prion diseases, if more efficient extraction procedures and more sensitive immunological reagents are used. Such technical improvements could contribute to more accurate diagnosis in animals affected naturally.

Animals↗
PubMed1997

Biochemical properties of protease resistant prion protein PrPsc in natural sheep scrapie.

Prions are infectious agents involved in neurodegenerative diseases, such as scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) in cows and Creutzfeldt-Jakob disease (CJD) in humans. These pathogens are characterized by unusual properties, and, in particular, by their strong resistance to common procedures of disinfection used against conventional microorganisms. A major component of highly infectious fractions is a proteinase K-resistant prion protein PrPsc (PrP-res), the normal host prion protein PrPc being sensitive to PK (PrP-sen). We used a biochemical approach to further characterize PrPsc protein in natural sheep scrapie. Western blot analyses using rabbit antiserum that recognized both normal and pathologic sheep prion proteins, were undertaken to study the biochemical behaviour of PrPsc extracted from brains of sheep naturally infected with scrapie after protease digestion and under denaturing conditions. Increasing concentrations of urea (1-7 M) or GdnSCN (0.25-3 M) and different pH from 2 to 11 were tested for their effects on protease resistance of PrPsc. Alkaline pH (pH = 10) and high concentrations of urea (> 3 M) and GdnSCN (> 0.75 M) greatly decreased the protease resistance of the prion protein. Identical experiments carried out on three different sheep from the same flock gave similar results. The biochemical behaviour of PrPsc under denaturing conditions and in the presence of proteinase K could thus provide a biochemical means for further characterization of different natural scrapie isolates.

Animals↗
PubMed1995

The bovine immunodeficiency-like virus (BIV) is transcriptionally active in experimentally infected calves.

We have studied the infection by the bovine immunodeficiency-like virus (BIV) in three experimentally infected calves, by polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR), from the peripheral blood mononuclear cells (PBMC). Two primer pairs located in the gag and pol regions of the viral genome allowed to detect the viral genomic DNA by PCR, as well as the unspliced genomic viral RNA transcript, by RT-PCR. We also present the evidence of the presence in peripheral blood mononuclear cells (PBMCs) of a mRNA transcript of the regulatory trans-activator tat gene, according to the splicing pattern of the viral genome, by use of reverse transcription followed by nested PCR. The active expression of the virus in these animals was further assessed by the sequential rescue of the virus from unstimulated PBMCs in cell culture, from 4 weeks until 15 months following the infection.

Animals↗
PubMed1995

[Bovine spongiform encephalopathy].

A new Transmissible Sub-acute Spongiform Encephalopathy (TSSE) appeared in 1986 in the bovine species, mainly concerning Great Britain where more than 100,000 cases have now been identified. This review describes the features of the disease that showed it belonged to this particular group of diseases. The currently available hypothesis about the origin of the disease, in Great Britain as well as in other countries where it has also been recognized, are presented. Lastly, the potential risks for the future, in the bovine species but also for other animal species or man, are discussed, in light of the known experimental data.

Animals↗
PubMed1993

Longitudinal transgastric echocardiographic views utilizing a single-plane probe: anatomic correlations and clinical applications.

In order to widen the diagnostic capability of single-plane transesophageal echocardiography, which has been so far confined to transverse imaging planes, we obtained four transgastric longitudinal echocardiographic views which have not been previously described. These views can image structures such as superior and inferior vena cava, the right ventricular inflow and outflow tract, the mitral apparatus and the ascending aorta, which are poorly visualized by transesophageal transverse single-plane echocardiography. Among 400 consecutive patients these scans gave relevant additional diagnostic information in 62 cases (15.5%) and provided the correct diagnosis in 37 (9.2%). There were no complications related to the longer gastric manipulation of the probe and the quality of the images was high. We conclude that longitudinal echotomographic scanning of the heart is not exclusively confined to the use of biplane or omniplane probes, but longitudinal views can be consistently obtained with a single-plane instrument.

Aorta↗
PubMed1993

[Bovine spongiform encephalopathy in Europe. Present and future].

Occurrence since 1986 and extension as an extended common source epidemic in United Kingdom of a new neurological bovine condition: bovine spongiform encephalopathy (BSE) initiated numerous epidemiological research actions in this country in order to discover the origin of this new disease, predict its evolution and implement control measures. In the same time epidemiological surveillance systems have been set up in several European countries leading to the identification of sporadic BSE cases in Ireland, Switzerland and France. In spite of the numerous informations published, a number of topics are not precisely known: identity and origin of BSE agent, influence of contaminated bovine genetics over disease development in contaminated bovine, infection incidence in herds where disease has been identified. As BSE is a member of the group of transmissible spongiform encephalopathies, concerns about foodborne transmission from cattle to human and inoculation of medicinal products containing bovine material and used for therapy or prevention in human beings or animals, has been expressed. The demonstration of iatrogenic transmission between human beings of Creutzfeld-Jakob disease has considerably influenced the implementation of measures to prevent the hypothetical risk for man to be infected by medicinal products or medical devises containing material of bovine origin.

Animals↗
PubMed1992

[Image perception and interpretation in senology. The relationship between the clinical picture, radiological sign and histology].

Once more, the authors are confronted with the difficult interpretation of senological images. When reviewing the radiologic features of a series including the symptomatic, the asymptomatic and the male breasts, the goal is to relate the patterns to clinical and histologic findings in order to improve the perception of the radiologist himself in transferring and integrating the information. The final conclusions, after reviewing the images, are: a) for the correct interpretation of senological images, the sign must be correlated with clinical findings and with data from other modalities; b) the radiologist's attitude must be always investigative and never exhaustive, due to the variability of all factors, which sometimes make a judgement of "radiological tranquility" in the breast impossible; c) the radiologist must, nowadays, improve his perception of senological images, thus becoming the one who knows how to correlate clinics to the images. By increasing his perception, his interpretation capabilities will certainly increase too.

Breast↗
PubMed1991

Ki-1 positive meningeal lymphoma in a patient with a history of Hodgkin lymphoma.

We describe the case of a woman in whom a Ki-1 lymphoma confined to the meninges developed nearly 4 years after complete remission of a Hodgkin lymphoma. The neurological symptoms appeared in two stages. The first, marked by multi-radicular impairment, cleared almost completely within a few months. The second, a year after the beginning of the first, manifested with a syndrome of meningeal irritation, which quickly led to death. We discuss the clinical course and the possible relationship between Hodgkin lymphoma and Ki-1 lymphoma.

Adult↗
PubMed1989

[Experimental reproduction and the course of contagious bovine pleuropneumonia in a group of cattle and goats: anatomoclinical aspects].

Five cows were inoculated with 3.10(9) CFU Mycoplasma mycoides subsp. mycoides. Five other cows and five goats were placed in close contact with inoculated cows. Clinical observations, serological survey and microbial excretion by culture for mycoplasma from tracheobronchial washes liquid were carried out during 4 months. Mycoplasmas excretion is detected before antibodies responses on all 10 infected cows. The cows never presented clinical respiratory signs and showed no or light lesions but one animal having typical lesions of acute form of contagious bovine pleuropneumonia. Goats do not seem to be susceptible and play no part in the spreading of the infection.

Animals↗
PubMed1989

[Correlation of the excretion of mycoplasma and kinetics of antibodies detected by complement fixation, passive hemagglutination and rapid seroagglutination in Mycoplasma mycoides subsp. mycoides SC experimental infection in cattle].

During an experimental reproduction of CBPP, 5 inoculated cows and 5 contacts cows were bled twice a week and antibodies research was performed using complement fixation test (CFT), passive haemagglutination test (PHAT) and slide agglutination test (SAT). In the same period, trachobronchial washings were performed weekly to detect and to count Mycoplasma mycoides subsp. mycoides SC. For four months these tests were used to compare antibodies kinetics with kinetics of mycoplasmas excretion. With titer over 40 as threshold of positivity, PHAT detects antibodies earlier than CFT and SAT at the beginning of infection, but fails to detect chronic carriers. In contacts cows no failure has been observed with CFT and SAT except during prodromic phase of infection. These results are valid for natural infections. However, for inoculated animals, most serious failures to detect infected cows occur.

Animals↗
PubMed1989

[Studies of the origin of false positive reactions in the serodiagnosis of contagious bovine pleuropneumonia].

Four groups of cattle were experimentally immunised by four mycoplasma species of "mycoides-like" group, Mycoplasma (M) capricolum, M. mycoides subsp. mycoides (LC), M. mycoides subsp. capri and M. species group 7 of LEACH (PG50). They were then bled weekly during 2 months to establish antibodies kinetics against homologous and heterologous antigens. The standard method of complement fixation test (CFT) used in Europe and a new ELISA test for diagnosis of contagious bovine pleuropneumonia were performed in comparison with passive haemagglutination test (PHA) against antigens used for experimental immunisation. Cross reactions obtained are rather equal to the degree of similitude between these mycoplasma species. With CFT-cross reactions are transitory and occur only while homologous titers are very high, particularly with "PG50" and the two caprine mycoides strains. ELISA results using a threshold of positivity of optical density of 0.20, were similar to that obtained with CFT except ELISA specificity is not so different from CFT one. This experimental model could explain some natural situations.

Animals↗
PubMed1987

Juxtapapillary choledochoduodenal fistula. Diagnosis and treatment in 19 cases.

Nineteen patients with distal juxtapapillary choledochoduodenal fistula diagnosed by endoscopic retrograde cholangiopancreatography are reported. Eighty-four percent of the patients had undergone previous operations on the biliary tract. Fistula appears to be mostly secondary to common bile duct exploration with rigid probes or to a technical mistake in performing sphincteroplasty. Spontaneous fistula secondary to the passage of a stone into the duodenal lumen may also occur. Common duct stones were responsible for the symptoms in most cases (70%). Endoscopic sphincterotomy showed good results in cholecystectomized patients with stones. Surgery directed to the fistula or biliary by-pass are not recommended. Uncomplicated fistula probably does not require treatment.

Adult↗