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Biomedical subjects

A Valentin

Publications and source records attributed to A Valentin.

At least 73 records · Page 4Linked to original sources
PubMed1995

Involvement of Candida albicans cell wall proteins in the adherence of blastospores to human buccal epithelial cells.

The adherence of Candida albicans to epithelial cells is one of the first steps in the development of candidiasis and therefore could constitute an interesting target for the prevention of infection. A yeast cell wall extract was prepared by using a C. albicans isolate (IVP 1453) highly adherent to buccal epithelial cells (BECs). This cell wall extract was separated by concanavalin A-affinity chromatography into two fractions referred to as Fr1 (proteic fraction) and Fr2 (mannoproteic fraction). The adhesion activity was mostly associated with the proteic fraction. This fraction was therefore retained and further fractionated by ion-exchange chromatography into two other fractions, referred to as Fr1a and Fr1b. The adhesion activity was mostly associated with the Fr1b fraction (56.4% adherence inhibition); it was not specific to the C. albicans isolate used during the cell wall extract preparation. The Fr1b fraction contained four major proteins with molecular masses of 30, 38, 47, and 54 kDa. Among these four proteins, those with molecular masses of 38 and 54 kDa could be involved in adherence mechanisms of C. albicans to human BECs.

Candida albicans↗
PubMed1995

Composition and antimalarial activity in vitro of volatile components of Lippia multiflora.

The essential oil of Lippia multiflora was prepared by hydrodistillation of leaves and stalks and characterized by GC and mass spectroscopy. The oil was tested for antimalarial activity on in vitro cultures of Plasmodium falciparum (FcB1-Columbia chloroquine-resistant strain and F32-Tanzania chloroquine-sensitive strain). The dilutions inhibiting the in vitro growth of the parasite by 50% 24 and 72 hr after administration of the essential oil to the parasite culture were 1/12,000 and 1/21,000, respectively. When tested on a highly synchronized culture, the essential oil inhibited growth mostly at the trophozoite-schizont step, indicating a potential effect on the first nuclear division of the parasite.

Animals↗
PubMed1995

Babesia divergens: an ELISA with soluble parasite antigen for monitoring the epidemiology of bovine babesiosis.

An enzyme linked immunosorbent assay (ELISA) for bovine babesiosis caused by Babesia divergens was developed to analyse the evolution of the serological status of cattle living in an enzootic area. The antigen used was a soluble extract of B. divergens obtained from in vitro culture. Specificity, evaluated with negative sera, was 96.6%. The ELISA was compared to indirect immunofluorescence analysis (IFA) on naturally or experimentally infected animals. It appeared that IFA was positive for at least seven or eight weeks; on the contrary, B. divergens-specific antibodies were only transitorily detected by ELISA. Furthermore, the ELISA was more sensitive than the IFA for the detection of post-infection antibody increases, particularly when infection-pressure was low. These results suggest that IFA and ELISA could be complementary tools in epidemiological surveys; indeed, this ELISA could be the most efficient tool to detect new infections in cohort monitoring.

Animals↗
PubMed1995

False diagnosis of myocardial infarction due to an extreme left sided cardiac rotation in two patients.

We present two patients with an extremely rare condition: abnormal cardiac levoposition. Alterations in the ECG caused by this congenital abnormality and additional chest symptoms led to the false diagnosis of previous myocardial infarction. Chest X-ray and echocardiography suggested cardiac malformation. Correct diagnosis of cardiac levoposition was established by magnetic resonance imaging.

Aged↗
PubMed1995

A 37-kilodalton glycoprotein of Babesia divergens is a major component of a protective fraction containing low-molecular-mass culture-derived exoantigens.

The supernatants of in vitro cultures of Babesia divergens Rouen 1987 in human erythrocytes, obtained by using a semidefined medium based on human high-density lipoproteins, were fractionated by gel filtration chromatography into four fractions, F1 to F4. The crude supernatant as well as each fraction adjuvanted with Quil-A protected gerbils from mortality due to a homologous infectious challenge. Analysis of the humoral response of the 10 protected gerbils with fraction F4, containing major proteins with molecular masses lower than 50 kDa, showed that a few antigens (from 50 to 17 kDa) could be important candidates for an improved vaccine against B. divergens babesiosis. As an immunodominant response was directed against the 37-kDa antigen (Bd37) in two different B. divergens strains tested, a polyclonal antibody directed against Bd37 was produced in a rabbit. In an immunofluorescence assay, the anti-Bd37 antiserum strongly labelled small internal vesicles of the merozoites and the cell surface was diffusely labelled after fixation, whereas on live merozoites, this labelling was not observed. [3H]glucosamine-radiolabelling experiments demonstrate that Bd37 is a glycoprotein. The Bd37 protein can also be labelled with [14C]palmitate but not with [3H]myristic acid. In Triton X-114 temperature phase partitioning of B. divergens-infected erythrocyte extracts, Bd37 was exclusively found into the detergent phase, indicating that the palmitoylated Bd37 protein was in the membrane fraction. In the in vitro supernatant, the glycoprotein Bd37 was found in a nonpalmitoylated form, indicating excretion and/or release of the glycoprotein from the merozoite.

Animals↗
PubMed1995

[Skin diseases as a reason for condemnation of broiler carcasses].

The analysis of losses in slaughtered broilers based on the results of poultry meat inspection in a poultry slaughterhouse in 1991-1993 has shown that skin diseases are the main reason for condemnation of carcasses, followed by polyserositis and aerosacculitis, underdevelopment, skeletal diseases, and ascites syndrome. The incidence of skin diseases increased continuously between 1991 and 1993. Amongst the skin diseases eight separate diagnoses were differentiated. Dermatitis with cellulitis, dermal carcinomatosis, skin tears, scabby hip, and breast blisters are the most frequent ones. However, the permanent increasing dermatitis with cellulitis as well as the frequency rank following dermal carcinomatosis are of utmost importance.

Abattoirs↗
PubMed1994

[Syringomyelia as a rare cause of respiratory insufficiency requiring ventilation].

For 17 years a now 45-year-old man had suffered from progressively more severe flaccid paresis of the arms and thoracic muscles, spastic paralysis of the legs and kyphoscoliosis. Artificial ventilation was required when he contracted pneumonia. Although it was being treated with antibiotics, frequent bronchoalveolar lavage had to be done because of repeated atelectases. After 6 weeks clonuses developed in the legs, predominantly on the right, stretch synergisms and opisthotonos. The pupils were small with sluggish reaction to light, and there was a positive "doll's head" phenomenon. The level of consciousness alternated between somnolence and sleepiness. Magnetic resonance imaging demonstrated cavities in cervical and thoracic spinal cord, supporting the diagnosis of an abnormal cerebrospinal circulation due to gliosis in syringomyelia. To secure cerebrospinal fluid drainage, the cerebellar tonsils were resected, together with a duraplasty and partial resection of the atlas. Following this he became fully conscious and the spastic state improved. During the following 8 weeks it became possible gradually to wean him from the artificial ventilation and achieve satisfactory mobilization so that he could be discharged to domiciliary care.

Combined Modality Therapy↗
PubMed1994

Tropism for primary monocytes and for monocytoid cell lines are separate features of HIV-1 variants.

We have analyzed the phenotype of five human monocytoid cell lines (U-937, THP-1, RC.2A, Mono Mac 6, and DD) and their capacity to support replication of HIV-1 strains with known tropism for T lymphocytes and mononuclear phagocytes. HIV-1 Ba-L, a prototype monocytotropic HIV-1 strain, was unable to establish continuous replication in any of the cell lines used. In contrast, the lymphotropic strain IIIB could replicate in all CD4-positive cell lines. We conclude that the capacity of HIV-1 isolates to replicate in established human monocytoid malignant cells does not correlate with the tropism of the virus for primary mononuclear phagocytes. Since monocytoid cell lines do not distinguish HIV-1 variants tropic for mononuclear phagocytes, we suggest the use of primary cells for studies of HIV-1 tropism.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Late follow-up results of operative ankle arthroscopy in patients under local anaesthesia.

The purpose of this study was to evaluate our long-term results of operative ankle arthroscopy in local anaesthesia, without tourniquet and antibiotic prophylaxis, and to see whether we could produce the same results other investigators had published using general anaesthesia. Between 1987 and 1992, 51 operative ankle arthroscopies were performed--all as out-patient procedures. Thirty-six patients had local anaesthesia, 7 had general anaesthesia, one had spinal anaesthesia and one had epidural anaesthesia. No prophylactic antibiotics were given. Indications for surgery were the same for patients who had local anaesthesia as for those who had the other types of anaesthesia. Nineteen patients had partial synovectomies, 8 had removals of osteophytes, 7 had debridements of osteochondral fractures, 6 had debridements of mild degenerative osteoarthritis, 3 had loose bodies and 2 had septic arthritis. After a mean of 3 years (range 1-8) the patients were sent a questionnaire. They were asked to rate activity level, pain, swelling, and limb stiffness on a four-grade scale pre- and postoperatively and to rate their total subjective improvement. They were also asked if they would undergo the same procedure again knowing the outcome of the procedure. Forty-five patients (88%) were available for follow-up. Thirty-four patients (76%) were improved, 10 remained unchanged, and one became worse after surgery. No correlation existed between preoperative symptom duration, sex, trauma, type of anaesthesia, postoperative diagnosis or type of surgical procedure. Minor complications occurred in 11% of patients. Eighty-four percent of the patients said they would undergo the same procedure again. The type of anaesthesia used did not influence this decision.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Relationship between fluconazole sensitivity of Candida albicans isolates from HIV positive patients and serotype, adherence and CD4+ lymphocyte count.

The sensitivity of fluconazole, serotype and adherence to buccal epithelial cells of 46 Candida albicans isolates was studied in vitro. Strains were isolated from 18 HIV-positive patients with variable CD4+ lymphocyte counts who were receiving long-term fluconazole therapy. Results showed that sensitivity to fluconazole correlated with serotype. Of the sensitive isolates 81.5% were serotype A and 18.5% serotype B, whereas of the resistant isolates 37.5% were serotype A and 62.5% serotype B. Sensitivity to fluconazole also correlated with adherence capacity, resistant isolates showing slightly less adherence to buccal epithelial cells than sensitive isolates. Weakly adherent isolates represented 87% of resistant isolates and only 63% of sensitive isolates. Resistant strains were isolated in highly immunocompromised patients. All strains isolated in patients with CD4+ lymphocyte counts above 200 lymphocytes/microliters were sensitive, whereas intermediate and resistant strains were isolated in patients with counts below 200 lymphocytes/microliters. Statistical analyses showed no correlation between adherence of isolates to buccal epithelial cells and CD4+ lymphocyte counts.

AIDS-Related Opportunistic Infections↗
PubMed1994

Characterization of a new 60 kDa apical protein of Plasmodium falciparum merozoite expressed in late schizogony.

Immunological cross-reactivity studies between the Apicomplexa Babesia divergens and Plasmodium falciparum allowed us to identify a P falciparum 60 kDa protein (Pf60) using an antiserum directed against a B divergens 37 kDa culture-derived exoantigen. In immunofluorescence assays (IFA), Pf60 appears as a doublet of fluorescent spots associated to the apical pole of merozoites. The doublet co-locates with two rhoptry components: the protein RAP-1 and the 140/130/110 (105) kDa rhoptry protein complex suggesting the rhoptry location of Pf60. The biosynthesis of Pf60, established by labeling experiments with [35S]methionine on synchronized cultures, and by immunofluorescence detection, occurred during late schizogony. The physico-chemical properties of Pf60, the absence of identified precursor forms and the absence of co-precipitation with other proteins indicated a new class of rhoptry protein. Pf60 was detected in all the different geographic P falciparum strains so far tested, with a slight variability in molecular mass ranging from 58 to 60 kDa. During the invasion process of erythrocytes by merozoites, the IFA showed the presence of the Pf60 in the apex of free merozoites, but not in invading merozoite, as well as in new ring-infected erythrocytes. Furthermore, immunoprecipitation assays indicated the presence of Pf60 in the culture medium, and its absence in new ring-infected erythrocytes. All together these results suggest a possible involvement of the Pf60 protein in the invasion process.

Animals↗
PubMed1994

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors lovastatin and simvastatin inhibit in vitro development of Plasmodium falciparum and Babesia divergens in human erythrocytes.

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors lovastatin and simvastatin inhibit the in vitro intraerythrocytic development of Plasmodium falciparum and Babesia divergens, with concentrations inhibiting parasite growth by 50% in the ranges of 10 to 20 and 5 to 10 micrograms.ml-1, respectively. For P. falciparum, the 50% inhibitory concentrations were in the same range whatever the chloroquine susceptibility of the strains tested (strain F32/Tanzania [chloroquine susceptible] or FcB.1/Columbia [resistant]). The stage-dependent susceptibility of P. falciparum to simvastatin was studied by subjecting synchronized cultures to 6-h pulses of drug throughout the 48-h erythrocytic life cycle. The most important inhibitory effects were observed between the 12th and 30th hours of the cycle, corresponding to the trophozoite stage. This period precedes the S phase and the nuclear divisions. Parasites in the newly formed ring stage (time zero to the 6th hour of the cycle) and the schizont stage (30th to 48th hour of the cycle) were weakly or not susceptible to simvastatin pulses.

Animals↗
PubMed1994

Dual tropism for macrophages and lymphocytes is a common feature of primary human immunodeficiency virus type 1 and 2 isolates.

We have investigated the ability of human immunodeficiency virus type 1 (HIV-1) and HIV-2 isolates to infect and replicate in primary human macrophages. Monocytes from blood donors were allowed to differentiate into macrophages by culture in the presence of autologous lymphocytes and human serum for 5 days before infection. A panel of 70 HIV-1 and 12 HIV-2 isolates were recovered from seropositive individuals with different severities of HIV infection. A majority of isolates (55 HIV-1 and all HIV-2) were obtained from peripheral blood mononuclear cells, but isolates from cerebrospinal fluid, monocytes, brain tissue, plasma, and purified CD4+ lymphocytes were also included. All isolates were able to infect monocyte-derived macrophages, even though the replicative capacity of the isolates varied. Interestingly, isolates with a rapid/high, syncytium-inducing phenotype did not differ from slow/low, non-syncytium-inducing isolates in their ability to replicate in monocyte-derived macrophages. Others have reported that rapid/high, syncytium-inducing isolates have a reduced ability to infect and replicate in monocytes. However, different methods to isolate and culture the monocytes/macrophages were used in these studies and our study. Thus, the ability of HIV isolates to replicate in monocytes/macrophages appears to be strongly influenced by the isolation and culture procedures. It remains to be determined which culture procedure is more relevant for the in vivo situation.

Cell Line↗
PubMed1994

Continuous propagation of RRE(-) and Rev(-)RRE(-) human immunodeficiency virus type 1 molecular clones containing a cis-acting element of simian retrovirus type 1 in human peripheral blood lymphocytes.

Molecular clones of human immunodeficiency virus type 1 that contained either 37 point mutations in the Rev-responsive element (RRE) that did not affect the overlapping env reading frame or both a mutated RRE and two mutations that eliminated Rev were constructed. The mutations in the RRE were shown to remove both negative and Rev-inducible positive effects of the RRE on gene expression (G. Nasioulas, A. S. Zolotukhin, C. Tabernero, L. Solomin, C. P. Cunningham, G. N. Pavlakis, and B. K. Felber, J. Virol. 68:2986-2993, 1994). Upon insertion of a cis-acting element of simian retrovirus type 1 (SRV-1) into these clones, both RRE(-) and Rev(-)RRE(-) clones were expressed efficiently. The element of SRV-1 has properties similar to those of the recently identified element of Mason-Pfizer monkey virus (M. Bray, S. Prasad, J. W. Dubay, E. Hunter, K.-T. Jeang, D. Rekosh, and M.-L. Hammarskjold, Proc. Natl. Acad. Sci. USA 4:1256-1260, 1994). We demonstrated that virus preparations produced after transfections of these SRV-1 element-containing molecular clones in human cells were infectious after cell-free transmission, that they replicated about 5 to 10 times less efficiently than wild-type virus, and that they were propagated continuously for more than 7 months in human peripheral blood mononuclear cells. Growth characteristics and sequence analysis of these viruses after long-term culture demonstrated that no RRE(+)Rev(+) revertants developed. These data demonstrate that human immunodeficiency virus type 1 Rev and RRE can be replaced by heterologous regulatory systems, resulting in efficient virus production. The resulting Rev(-)RRE(-) virus can be prepared and propagated efficiently in tissue culture and can be used for further studies of the life cycle of the virus. The data also suggest that Rev acts exclusively through the RRE interaction and that it does not have any additional essential function in the life cycle of the virus.

Base Sequence↗
PubMed1994

Initial experience with intravascular ultrasound imaging during carotid endarterectomy.

BACKGROUND AND PURPOSE: To assess the feasibility of intravascular ultrasound imaging during carotid endarterectomy. METHODS: Intravascular ultrasound imaging was performed during carotid endarterectomy in eight patients using an over-the-wire catheter system with a 30-MHz ultrasound probe. In vitro studies were carried out before the intraoperative application, paying special attention to visualization of the wall layers of normal carotid arteries, structures of more or less diseased vessels, and surgically placed materials such as patch, suture material, and fibrin glue. Although intravascular ultrasound failed to distinguish between intima and media in areas of normal intima, fibrotic and calcified plaques were detected clearly. Dacron patch as well as sutures were identified as highly reflective structures. RESULTS: In seven of the eight patients studied, intravascular ultrasound yielded cross-sectional images of good quality allowing identification of the vessel layers and the structures at the endarterectomy site. In all patients the three layers of the vessel wall were clearly differentiated and the transition zone between the site of endarterectomy and the genuine vessel appeared smooth without intimal flaps or residual arteriosclerotic plaques. In one patient severe eccentric thickening of the media was detected in the distal internal carotid artery. Neither damage of the vessel layers by the shunt nor thrombus formation in the operating area and the internal carotid artery were detected. CONCLUSIONS: Intravascular ultrasound lends itself as a potentially valuable method of quality control during carotid endarterectomy. The method seems to enable an accurate evaluation of the endarterectomy site and the search for residual plaques.

Adult↗
PubMed1994

Embolic stroke by compression maneuver during transcranial Doppler sonography.

BACKGROUND AND PURPOSE: Embolic complications during ultrasound examinations are a rare cause of neurological deficits. The present case documents the occurrence of embolism by a nonobstructive compression maneuver during transcranial Doppler examination, resulting in a minor stroke. CASE DESCRIPTION: A 63-year-old man suffered from recurrent transient ischemic attacks. Duplex sonography showed a small echogenic plaque at the right carotid bifurcation. During transcranial Doppler studies with a reverberating compression maneuver of the right common carotid artery low in the neck, multiple emboli signals were detected, and the patient developed a left-sided hemiparesis with slurred speech. Funduscopy revealed cholesterol emboli in the inferior temporal arteriole of the right eye. These findings suggested embolization as the cause of the stroke. CONCLUSIONS: Compression maneuvers should not be performed in patients with recent neurological symptoms, even in the case of only small lesions in the extracranial carotid territory.

Carotid Artery Diseases↗
PubMed1994

[Adherence of isolated Candida albicans strains from HIV+ infected patients to buccal epithelial cells: correlation with serotype, sensitivity to fluconazole and virulence].

During infection by human immunodeficiency virus (HIV), oral pseudomembranous candidiasis frequency is high. Adherence of Candida albicans to epithelial cells constitutes one of the first step in the setting up of candidiasis. Adherence ability of Candida albicans to buccal epithelial cells (BEC) is estimated for 83 isolates. The yeasts are isolated from buccal swabs from HIV+ patients with clinical oropharyngeal candidiasis. Results show that Candida albicans ability to adhere to BEC is variable within isolates; it appears that most of the isolates are weakly adherent. In addition, adherence is not correlated with the serotype A or B of yeasts. We do not either observe any correlation between adherence capacity and sensibility of yeasts to fluconazole. Moreover, no correlation is observed between a group of 13 genetically identical isolates (analysed on 21 loci with isoenzymes method) and their adherence to BEC. Finally, Candida albicans virulence, which is studied in vivo on intravenously infected mouse model, does not seem to be correlated with capacity of each yeast to adhere on BEC in vitro.

AIDS-Related Opportunistic Infections↗