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Biomedical subjects

Y Tselentis

Publications and source records attributed to Y Tselentis.

At least 73 records · Page 4Linked to original sources
PubMed1994

Transmission cycle of murine typhus in Greece.

A field study, based on a follow up of the 49 human cases of the disease that occurred on the island of Evia in 1985, has established the transmission cycle of murine typhus in Greece for the first time. In 1993, two types of traps were used to catch 53 rats, all of them Rattus norvegicus, in the localities where the cases had occurred. Some 300 fleas, all of them probably Xenopsylla cheopis, and a few ticks and mites were collected from the rats. Eight of the fleas were found positive for Rickettsia typhi by PCR and anti-R. typhi antibodies were found in the sera of 48 (91%) of the rats at titres between 1:8 and 1:524,288 and in 22 (42%) at titres > 1:256. The commensal rat population in the general area of study was both ubiquitous and abundant. Murine typhus is obviously endemic in the area and probably of much greater public health significance than the number of reported cases indicates.

Animals↗
PubMed1994

Leishmaniasis in greater Athens, Greece. Entomological studies.

Greater Athens, the largest urban area in Greece, has a population of 3.1 million and is home for most of the human and canine cases of visceral leishmaniasis (VL) reported in Greece. Seven species of sandflies (Diptera: Psychodidae) were identified in light- and sticky-trap surveys in the area in 1993. Although none of the flies was found in wooded areas or scrub, flies were collected from quarries, corrals, wells, walls, houses and animal shelters. There were small 'island' populations in residential districts and moderate or large populations in the quarries and corrals in the foothills of the mountains bordering the area and in the hills near the city centre. Phlebotomus neglectus, the putative vector of VL in the area, was ubiquitous; it predominated in the quarries and was common in the sampled corrals and residential habitats. The distribution, abundance and seasonal activity of all seven species of sandflies are described and discussed.

Animals↗
PubMed1994

Murine yeast gut flora affected by tetracycline, metronidazole and norfloxacin.

Three-month old, male Crl:CD1(ICR) BR mice, were fed food containing Candida albicans, while other mice of the same type were fed regular food. Both groups of mice were subsequently given orally either antibiotics or normal saline for a 10-day period. The stools of all mice were cultured before, at the end, and one week after the end of the antibiotic treatment, to determine the level of gut colonization by the yeast. The mice fed Candida and treated with antibiotics had substantially higher Candida counts in their stools than control mice fed C. albicans and treated with saline. The concentrations of Candida in the stools of mice treated with tetracycline were much higher when compared to those of mice treated with metronidazole and norfloxacin. Tetracycline was associated with a statistically significant increase of gastrointestinal Candida colonization. Yeast was not found in the stools of mice fed regular food and treated with antibiotics or saline. Histopathologic examination did not reveal dissemination of Candida in the visceral organs of any mouse.

Administration, Oral↗
PubMed1994

Effects of broad-spectrum antibiotics on colonization of gastrointestinal tracts of mice by Candida albicans.

Three-month-old, male, Crl:CD1 (ICR) BR mice were fed chow containing Candida albicans or regular chow. Subsequently, both groups were given either antibiotics or normal saline for 10 days. Stool cultures were performed immediately before administration, at the end of antibiotic administration, and 1 week after the discontinuation of antibiotics, to determine the effect on the concentration of C. albicans in the stools. The stools of mice fed C. albicans and given antibiotics had substantially higher Candida counts than those of control mice fed C. albicans and given saline. Significantly higher candidal concentrations were observed in the stools of mice given chloramphenicol compared with those of mice given ciprofloxacin, sulfamethoxazole-trimethoprim, and ampicillin. No mice developed histopathological evidence of local gastrointestinal invasion or disseminated candidiasis. In this mouse model, Candida colonization increases substantially after the administration of antimicrobial agents with broad spectra and anaerobic activities.

Animals↗
PubMed1994

Surgical wound infection caused by Rahnella aquatilis.

Rahnella aquatilis is a water-residing gram-negative rod, a member of the family Enterobacteriaceae, isolated rarely from clinical specimens of immunocompromised patients. A case of a surgical wound infection caused by R. aquatilis in a patient who underwent a prosthetic surgical intervention is reported. The presence of inducible beta-lactamase was suggested by the disk induction test and the conventional agar dilution assay. Literature on R. aquatilis infections in humans is reviewed.

Enterobacteriaceae↗
PubMed1994

Isolation and identification of a rickettsial strain related to Rickettsia massiliae in Greek ticks.

Adult ticks were collected in a rural area of central Greece in order to isolate and identify rickettsiae. A hemolymph test using Gimenez staining was used for detection, while simultaneous isolation was performed using the shell-vial technique. Serologic, antigenic, and genomic characterization of the isolates was achieved by microimmunofluorescence, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting, the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP), and pulsed-field gel electrophoresis (PFGE), respectively. Although none of the 242 collected ticks was positive by the hemolymph test, one rickettsial isolate, designated GS, was obtained by the shell-vial technique. This isolate originated from a female Rhipicephalus sanguineus. Microimmunofluorescence serologic typing by the method of Philip and others demonstrated that GS belongs to the same serotype as the recently isolated Rickettsia massiliae (Mtu1). Protein analysis by SDS-PAGE and immunoblotting by Western blot revealed similar profiles between the two rickettsiae. Using Alu I, Rsa I, and Pst I restriction endonucleases in PCR-RFLP analysis, GS and R. massiliae were found to possess identical restriction sites. However, PFGE showed differences when the two genomes were digested with Bss HII and Sma I restriction endonucleases, in spite of their equal size. In conclusion, the first rickettsial isolation in Greece was found to be antigenically identical and genotypically close to the French isolate R. massiliae, despite small differences showed by PFGE.

Animals↗
PubMed1993

Studies on Echinococcus granulosus using the scanning electron microscope. I. Preparations of the parasite for infection of the final host.

The development of the protoscoleces of Echinococcus granulosus was studied after chemical stimulation, which mimics that offered by the final host. This stimulation resulted in some morphological changes in the parasite and to its evagination. These changes prepare the parasite to infect the intestine of its final host. The external morphology of the protoscolex body and of the germinal layer of the cyst and brood capsule were studied using the scanning electron microscope (SEM). Findings were related to other studies using the transmission electron microscope (TEM). The morphology of the flame cell is described and four cases of teratogenesis are reported.

Animals↗
PubMed1993

Studies on Echinococcus granulosus using the scanning electron microscope. II. The hooks.

The morphology of the hooks of Echinococcus granulosus at the protoscolex level was studied by means of scanning electron microscopy. Hooks were uncovered in situ and also freed from the rostellum so as to study them in detail. There were two types of hooks: those of the upper row, which were larger and had a projecting, rounded stout guard, and those of the lower row, which were smaller and had a flattened guard. These and other differences in the morphology of the two types of hooks were studied and related to the differences in their function.

Animals↗
PubMed1993

Prospective evaluation of effects of broad-spectrum antibiotics on gastrointestinal yeast colonization of humans.

This study evaluated the effects of broad-spectrum antibiotics on the gastrointestinal (G.I.) yeast flora of humans and correlated the findings with those obtained from a mouse model of G.I. colonization by Candida albicans. We prospectively studied 46 adult cancer patients who received one of five broad-spectrum antibiotics (ceftriaxone, ceftazidime, ticarcillin-clavulanic acid, imipenem-cilastatin, and aztreonam) as therapy for infections. Quantitative examination of yeast colonization of stools was conducted at the baseline, at the end of antibiotic treatment, and 1 week after discontinuation of therapy. Antibiotics with anaerobic activity (ticarcillin-clavulanic acid) or high G.I. concentrations (ceftriaxone) caused a higher and more sustained increase in G.I. colonization by yeasts than did antibiotics with poor anaerobic activity (ceftazidime and aztreonam) or a low G.I. concentration (imipenem-cilastatin). These results were similar to those obtained with a mouse model of G.I. colonization by C. albicans that involved the same antibiotics. Hence, the mouse model may be useful for evaluation of yeast colonization of the human G.I. tract.

Adult↗
PubMed1993

Rickettsia conorii in Greece: comparison of a microimmunofluorescence assay and western blotting for seroepidemiology.

Since 1972, there have been no reports of Mediterranean spotted fever (MSF) in Greece. In 1991, a seroepidemiologic survey was conducted in three rural villages in the Province of Fokida in central Greece, using both an immunofluorescence assay (IFA) and Western blot to evaluate the prevalence of specific IgG and IgM antibodies to Rickettsia conorii, and to compare these two techniques. Of 254 sera tested by IFA, 148 (58.3%) were positive for IgG at a titer > or = 32 and 117 (46.1%) at a titer > or = 64. Two sera were positive for IgM at a titer > or = 32. Among the IFA-positive sera, 115 reacted against the specific protein antigen (SPA) using Western blotting and were considered as confirmed positive results, indicating a seroprevalence of 45.3%. Using the SPA reaction as a reference, the IFA diagnostic value of a single serum is poor in such an endemic area, suggesting the need for more specific tests. The results of this study have led us to conclude that for seroepidemiologic use, the IFA is not specific for MSF. Thus, the IFA is useful for sero-epidemiologic analysis only in areas where the true prevalence of MSF has been estimated using Western blotting.

Adult↗
PubMed1992

Clinicoepidemiological study of murine typhus on the Greek island of Evia.

Cases of murine typhus were described in Chalkis, capital town of the island Evia in Greece. In the present work a prospective study on murine typhus was carried out in Chalkis General Hospital in 1985, is presented. During this year 49 cases, serologically confirmed using indirect fluorescence assay, were diagnosed. Signs and symptoms of the patients as well as preliminary epidemiological data are reported in this paper.

Adolescent↗
PubMed1992

Serodiagnosis and screening of canine visceral leishmaniasis in an endemic area of Corsica: applicability of a direct agglutination test and immunoblot analysis.

For effective control of visceral leishmaniasis caused by Leishmania infantum in the Mediterranean area, the detection of infected dogs is of utmost importance. To assess the suitability of a direct agglutination test (DAT) and immunoblot analysis in serodiagnosis and screening of infected dogs under field conditions, a study was performed on 113 dogs in an endemic area of Corsica. Twenty one of 22 parasitologically confirmed cases were correctly diagnosed by both tests, and 100% specificity was found when 11 dogs with other diseases were examined. Interestingly, eight of 80 apparently healthy dogs from the same area were found to be parasite-positive by the DAT test as well as by the immunoblot. Although both tests were equally sensitive and specific, based on both the feasibility of its application in field conditions and ease of performance, we consider the DAT to be more suitable for serodiagnosis and large-scale screening of infected dogs.

Agglutination Tests↗
PubMed1986

[Culture systems for production of promastigote and amastigote forms of Leishmania. Application to serological diagnosis and therapeutic trials].

Several species of leishmania and three methods of cultivation: monophasic, biphasic and co-cultivation were used in a compared study bearing on the intensive production of leishmania. In addition by applying, a new in vivo model, comprising an injection of sarcomatous cells and promastigotes into BALB/c mice and also an extraction on a discontinuous gradient (Radioselectan 60%), it was possible to obtain highly purified isolates of amastigote forms. The use of two antigens: promastigotes and amastigotes, is to be recommended for the serological diagnosis, by indirect immunofluorescence, of kala-azar. The new in vivo model merits further consideration for research concerning new molecules active against leishmania.

Animals↗
PubMed1985

[Measles vaccination in the Sudan-Sahel region of Africa. Absence of the immunodepressive effect of malaria].

A survey aiming at assessing the effectiveness of anti-measles vaccination was carried out in a rural Upper-Volta population. The haemagglutination inhibition technique was used for detection of anti-measles antibodies; a reciprocal antibody titer of 20 or more was considered as a positive one and the subject considered as immunized. In the age group of 1-3 years old studied here, malaria does not seem to be a factor that modulates the ability of vaccinated subjects of producing anti-measles antibodies. Thus the immunodepressive properties of the Plasmodium is not observed in this immunizing system which effectiveness has been further improved by the development of thermostable vaccines.

Burkina Faso↗
PubMedDate not supplied

Gram-negative bacteremia in non-neutropenic patients: a 3-year review.

The causative organisms, clinical manifestations, factors influencing prognosis, and other epidemiological characteristics of 81 episodes of bacteremia due to gram-negative organisms, in non-neutropenic patients, were studied retrospectively during a 3-year period (1992-1994) at the Department of Internal Medicine of the University Hospital of Heraklion, Crete, Greece. The gram-negative bacteremia incidence was 2% and the overall mortality 12%. All 81 patients had fever; Escherichia coli was the most frequent organism isolated (from 47 patients--58%) and was associated with shock (9/47), disseminated intravascular coagulation (DIC) (8/47), anuria (5/47), adult respiratory distress syndrome (ARDS) (3/47), and pneumonia (1/47). Other less frequent gram-negative microorganisms were Klebsiella spp. (ten patients; 12%), Pseudomonas spp. (7; 7%), Salmonella spp. (5; 6%), Enterobacter spp. (5; 6%), Proteus spp. (3; 3.4%), Stenotrophomonas spp. (3; 3.4%), and Acinetobacter spp. (1; 1.2%). ARDS. shock, DIC, anuria, presence of central venous catheter, urinary catheter, unknown origin of infection and inappropriate treatment were significantly associated with a higher death rate. Early initiation of appropriate therapy was the most important intervention that favorably affected the outcome of gram-negative bacteremias in this patient population.

Adult↗