Biomedical subjects

E Pichard

Publications and source records attributed to E Pichard.

At least 37 records · Page 2Linked to original sources

PubMed1995

Synthesis and maturation of viral transcripts in herpes simplex virus type 1 infected HeLa cells: the role of interchromatin granules.

The response of the cellular RNA processing machinery to herpes simplex virus type 1 (HSV-1) infection was studied at the ultrastructural level in HeLa cells and compared to the distribution of RNA polymerase II molecules and viral RNA. Immunogold labeling of RNA polymerase II molecules revealed that viral genome transcription was restricted to filaments in an intranuclear, virus-induced region. This region also contained viral RNAs as revealed by in situ hybridization of two biotinylated viral DNA probes: a probe encompassing a limited portion of the viral genome (the F fragment) and a probe for the total genome. In addition, the latter probe revealed large amounts of viral RNA within the clusters of interchromatin granules, intranuclear structures of normal cells that became enlarged during HSV-1 infection. Components of spliceosomes were localized by in situ hybridization with biotinylated U1 and U2 DNA probes. The large viral region contained only traces of U1 and U2 RNAs, probably because of the low frequency of splices of viral transcripts. The clusters of interchromatin granules, however, accumulated U1 and U2 RNAs with the same frequency as in noninfected cells. Poly(A) RNA was detected by in situ hybridization of a biotinylated poly(dT) probe. Some was present over the filaments of the virus-induced region but most was accumulated in the clusters of interchromatin granules. Our data suggest, therefore, that the clusters of interchromatin granules, in addition to their involvement in spliceosome component assembly, might also be a transient storage site for some families of viral mRNA, possibly a sorting site that regulates their migration.

Adenine↗

PubMed1994

Kinetics of spiramycin/metronidazole (Rodogyl) in human gingival crevicular fluid, saliva and blood.

The peripheral distribution of spiramycin and metronidazole, which are combined in the proprietary drug "Rodogyl", has been studied in gingival fluid, saliva and blood after a single administration to 12 healthy volunteers and after repeated administration to 4 patients with recurring severe periodontitis. Analysis of the 2 antibiotics have been performed at regular intervals during the 24-h period immediately following the administration to the volunteers and after the 1st and the 15th days of repeated administration to the patients. The results show that gingival fluid contains concentrations of spiramycin and metronidazole higher than those needed to inhibit the growth of periodontopathic bacteria. Spiramycin was found at higher concentrations in GCF than in blood, although this feature was not found for metronidazole, which was administered simultaneously and showed similar concentrations in both fluid and serum. Such high concentrations persist for a long time, and suggest the potential of this compound in the treatment of severe cases of periodontitis.

Adult↗

PubMed1994

[Anatomo-clinical study of chronic gastritis in Mali].

The aim of our study was to evaluate the frequency of chronic gastritis and its anatomoclinical aspects in Mali. Within thirteen months of prospective study, we have recorded seventy four chronic gastritis histologically confirmed which represented 3.28% of the total oesogastroduodenal pathologies registered during the same period (2256 cases). Chronic gastritis has been most observed between 31 to 40 years (24.3%) and women were affected (sex ratio = 0.6). Households and civil servants were predominant. The precocious burning epigastralgy just after the meal was the main motive of the examination and chronic gastritis has been a fortuitous discovery. The basic alimentation included smoked or dried fish, peanuts, "tô" and salt. The most frequent endoscopic aspect was the congestive one. The duodenogastric reflux was not negligible. The diffuse form and antral localisation were more frequent. Five displasiae and four intestinal metaplasiae have been found.

Adolescent↗

PubMed1993

Secnidazole concentrations in plasma and crevicular fluid after a single oral dose.

Metronidazole and related nitroimidazole derivatives, including ornidazole and tinidazole, have been used successfully in the treatment of periodontal diseases. The purpose of this study was to measure secnidazole (another nitroimidazole derivative) concentrations in plasma and gingival crevicular fluid (GCF) after intake of a single oral dose. Secnidazole concentrations were estimated in 11 human healthy volunteers after a single dose of 2 g taken orally. Samples of blood and GCF were collected before intake and during the following 72 h. A high-performance liquid chromatography (HPLC) method has been developed for the determination of secnidazole in microsamples (1 to 3 microliters) of GCF. The mean peak blood and GCF levels were equal to 40.5 +/- 9.4 micrograms ml-1 at 2 h in blood and 26.4 +/- 7.0 micrograms ml-1 at 1 h in GCF, respectively. Apparent elimination half-life was 28.8 h (blood) and 30.4 h (GCF), respectively. These results show that the rate and extent-absorption of secnidazole are slightly higher in blood than in GCF, but the elimination of the drug is similar in the two body fluids.

Absorption↗

PubMed1993

Superiority of in situ hybridization over immunolabeling for detecting DNA on Lowicryl sections: a study on adenovirus-infected cells.

We investigated the intranuclear distribution of viral genomes in adenovirus Type 5-infected HeLa cells on ultra-thin sections of Lowicryl K4M-embedded material by immunolabeling of DNA and in situ hybridization with a viral DNA probe. Monoclonal AC-30-10, raised against double- and single-stranded DNA (dsDNA, ssDNA), and HB2 antibodies, raised against only the dsDNA, were used. Both antibodies intensely labeled the condensed host chromatin and the virus-induced substructures containing inactive encapsidated and non-encapsidated viral genomes. The antibodies labeled only slightly those substructures containing replicating and transcribing viral genomes. Viral ssDNA, which is accumulated within well-delineated compact fibrillar structures, was not revealed by AC-30-10 even after elimination of the proteins of the section. In situ hybridization detected all of these types of viral DNA, depending on the protocol used. Therefore, the sensitivity of in situ hybridization for detecting DNA appears superior to immunolabeling with specific antibodies.

Adenoviridae↗

PubMed1993

A new approach to combatting iodine deficiency in developing countries: the controlled release of iodine in water by a silicone elastomer.

OBJECTIVES: Four hundred million people or more may be exposed to iodine deficiency worldwide, in developing countries in particular. Because of the practical problems with existing methods for the large-scale prevention of iodine deficiency, the authors developed a new approach to collective prophylaxis. METHODS: This approach relies on the controlled diffusion of iodine into water from a silicone elastomer. Silicone matrices installed in a bore well released iodine at a rate sufficient to permit the daily per capita intake of at least 100 micrograms of iodine, the amount recommended by the World Health Organization. The matrices were tested over 1 year in a village in Mali, West Africa, an area in which goiter was highly endemic. The effects on the well water and population were compared with those of a placebo system in a control village. RESULTS: An increase in urinary iodine levels was observed in the treated population, and after 12 months the incidence of goiter had fallen from 53.2% to 29.2%. CONCLUSIONS: This new concept, adaptable to all sources of water supply, may contribute to the eradication of iodine deficiency.

Adult↗

PubMed1993

[Esophagitis in Bamako. Apropos of 228 cases].

Our main objective has been to study the prevalence of oesophagitis by upper digestive endoscopy. Within 12 months, we have registered 228 cases of oesophagitis out of 612 oesophagean anomalies (37.25%) during 3019 fibroscopies. Oesophagitis has been found to 63.59% in cases in young adult men. Peptic oesophagitis has been most frequent and its congestive aspects most current. The main indication of endoscopy in patients suffering of oesophagitis has been epigastralgies.

Adult↗

PubMed1992

Segregation of viral double-stranded and single-stranded DNA molecules in nuclei of adenovirus infected cells as revealed by electron microscope in situ hybridization.

Formation of progeny viruses in the nuclei of HeLa cells infected with adenovirus type 5 was studied at the ultrastructural level by in situ hybridization techniques allowing specific detection of either viral double-stranded DNA (dsDNA) or single-stranded DNA (ssDNA). Prior to the initiation of replication of viral genomes, infective DNA molecules which entered the nucleus of the target cell were randomly distributed among host chromatin fibers including nucleolus-associated chromatin. They were double-stranded, that is, without single-strand breaks. Such association of viral DNA with host condensed chromatin also occurred in mitosis. The initiation of viral genome replication occurred simultaneously with the appearance in the nucleoplasm of small fibrillar regions containing intermingled viral dsDNA and ssDNA. Later, at the intermediate stage of nuclear transformation, viral dsDNA and ssDNA molecules were almost entirely separated into two contiguous substructures. At this stage, viruses were observed occasionally in the vicinity of viral ssDNA accumulation sites. Still later, an additional substructure developed in the centre of the nucleus which consisted of large quantities of viral dsDNA, traces of viral ssDNA and abundant viruses. Portions of viral ssDNA were attached to some viruses even at late stage of nuclear transformation, an association which strongly suggests the occurrence of encapsidation of at least some of the viral genomes while they are still engaged in replication.

Adenovirus Infections, Human↗

PubMed1992

Alterations of nucleolar ultrastructure and ribosome biogenesis by actinomycin D. Implications for U3 snRNP function.

We have studied, at the electron microscope level, the reorganizations of nucleolar ultrastructure induced by actinomycin D (AMD) in different conditions of drug treatment associated with an inhibition of rRNA synthesis. We have analyzed in parallel the localizations of ribosomal genes, of their transcripts, of various pre-rRNA intermediates, as well as of U3 RNA and fibrillarin by in situ hybridization with nucleic acid probes and immunocytological detection on thin sections of human and mouse cells. Consistent with previous observations, dense fibrillar component (DFC) and granular component (GC) appear to contain distinct pre-rRNA species at different stages of their processing. DFC appears as a major site of U3 RNA accumulation, but a very substantial fraction of nucleolar U3 RNA is also found in GC, colocalizing with partially processed pre-rRNAs. Remarkably, the major nucleolar components retain their ultrastructural appearance when extensively depleted of their pre-rRNA moiety, and ribosomal genes are always detected over fibrillar center (FC), even after extended AMD treatments which result in the characteristic segregation of nucleolar components. Moreover, while for GC the U3 RNA and pre-rRNA contents evolve in parallel following the cessation of rRNA synthesis, a dramatic uncoupling is observed for DFC. The persistent presence of U3 RNA and fibrillarin after pre-rRNA depletion suggests that DFC could represent an anchorage site for U3 snRNPs, before their entering another cycle of pre-rRNA processing reactions.

3T3 Cells↗

PubMed1992

[Prevention of iodine deficiency disorders in children in the rural African zone].

The effectiveness of iodinated silicone polymers placed in bore wells for combating goiter in children under 15 years of age was evaluated in two villages in Mali. Of the 581 included children, 367 did and 214 did not receive supplemental iodine. Overall, follow-up data at one year were available for 86% of study subjects. At baseline, Goiter was present in 43.3% of the children in the supplemental iodine group and in 69.2% of controls. Stage G1B predominated in both sexes. After one year, 36% of the goiters had resolved in the supplement group. Effectiveness of iodine supplementation was greater in young children with small goiters. Urinary iodine levels returned to normal by the third month. Iodine levels in the supplemented water remained above 50 micrograms/l throughout the year; daily intake of iodine was 50 to 100 micrograms. In the unsupplemented village, 21 new cases of goiter occurred, for an annual incidence of 40%.

Adolescent↗

PubMed1992

[Tolerance of ivermectin treatment of rural communities infected by savannah onchocerciasis in Mali].

In an open clinical trial in phase IV, 856 onchocerciasis infected subjects received 150 micrograms/kg of ivermectin in May 1987. While 607 were included as witness. This cohort was revisited 7 and 12 months after. In June 1988, the same treatment was administrated to the previously treated subjects, and the witnesses received their first ivermectin' dose. The clinical tolerance of the treatment appears good and, even improved during the second dose one year after. Among the subjects treated in May 1987, 15.2% of them showed secondary reactions mostly discrete or moderate, precocious and quickly reversible after a second dose. Only 8 of them were incommodated in their daily occupations. A second treatment of these same subjects one year later, caused reactions of feeble intensity 3.7% only. The research of intolerance risk factors, incriminated the high density of microfilaremia. This incite to be careful in mass treatment of hyperendemic area.

Humans↗

PubMed1991

[Impact of curtains and blankets impregnated with permethrin on the malarial indicators and the number of malarial attacks per child in a village in an area hyperendemic for malaria on the Malian savannah (preliminary results of the first year study)].

From May 1989 to June 1990 an experimental study has been undertaken in two village's malarial hyperendemy of the Malian savannah. This study's objective was to test the effectiveness, on paludometric parameters and the openness of the population to the impregnated curtains and blankets, of permethrin as strategy of controlling malaria. The experimental village (Tiénéguébougou) and the control one (Kambila) are located in the same ecosystem and as at least 3 km any from each other. The impregnated curtains were installed in all the experimental village's houses and all the 216 residents have received impregnated blankets. The entomological, parasitical and clinical parameters were measured monthly from may 1989 to november 1989. The impregnated curtains were accepted by the population. However the impregnated blankets were little successful. Their impact on the entomological parameters is remarkable with a reduction of more than 98% of ma and the rate of entomological inoculation (REI) in the houses. The reduction of parasitical index is much less perceptible. The effect on the parasitical pressure was manifested by a highly significant difference of splenic index between the two villages (lower in the control village). The main vectors belong to complex: A. gambiae s.l. which rate of parity was not affected by the impregnated material. Very efficient against the harmfulness of in house hematophagic insects, the curtains impregnated by pyrethroids are not sufficient for interrupting the transmission of malaria. Actually, the study is continued for 2 years with a best evaluation of the malarial morbidity.

Adolescent↗

PubMed1991

[Retino-vitreous hemorrhage in hemoglobinopathies].

During 15 months all the patients with retinal or vitreous hemorrhages diagnosed in departments of ophthalmology or internal medicine in Bamako (Mali) were submitted to an aetiological assessment. Only patients with hemorrhages caused by a general aetiology were included in the study. 64 cases were selected according to these criteria. Hemoglobinopathies were involved in 14.1% of cases, high blood pressure in 31.8%, diabetes mellitus in 10.9% and miscellaneous causes in 15.6%. In 26.6% of cases an association between several of these aetiologies was observed. SC hemoglobin was the most frequent and the most serious. AS and AC traits were involved in 2 retinal hemorrhages' cases. AS and AC traits' responsibility in ocular hemorrhages associated with diabetes mellitus or high blood pressure was doubtful. A frequent association of sickle cell trait and high blood pressure was noticed. One case of Eales syndrome is reported during a diabetes mellitus-AS trait. All the patients were submitted to a treatment by pentoxifylline. Moreover 5 patients were treated by a laser coagulation and 2 patients by cryoapplication. The interest of the hemoglobin electrophoresis for the aetiologic assessment of retinal and vitreous hemorrhages is stressed.

Adolescent↗

PubMed1991

[General causes of retinal and vitreous hemorrhages in Mali].

Sixty four cases of retinal and vitreous hemorrhages are reported during a 15 months prospective study in Bamako. Main diseases associated with hemorrhages are high blood pressure (56% of cases), hemoglobinopathies (33%) and diabetes mellitus (23%). In 28% of cases several aetiologies are connected. SC hemoglobin is a frequent aetiology of vitreous hemorrhage (40%). Hemoglobin AS and AC, generally asymptomatic, are also liable to hemorrhages. Terson and Eales syndromes, Werlhof disease, hemophilia and AIDS are most uncommon. In 8% of cases there is not any aetiology.

Adolescent↗

PubMed1991

[Evolution of endemic goiter in Malian women and children after a year of enrichment of drinking water with iodine using diffusers made of silicone].

A new method for iodine deficiency disorders prevention is tested during one year in a rural area of Mali. Silicone and sodium iodide made diffusers are set up inside 2 villages' drillings. Their efficiency is compared with a placebo. Supervision criteria are evolution of goiter, rates of iodine in water and ioduria of the population, specially women and children. In the treated villages a decrease of goiters' size of the younger people is observed. Iodine rates in treated drillings water stay during 12 months between 150 and 300 micrograms/l with a minimum intake of 150 micrograms/day/person. The means of ioduria rates from less than 25 micrograms/l before treatment (severe deficiency) increase to more than 100 micrograms/l after six months of treatment (no deficiency).

Adolescent↗

PubMed1991

[A new combined vaccine against yellow fever and measles in infants aged 6 to 24 months in Mali].

In a rural area in Mali, 453 children were randomly enrolled in a study comparing the safety and the immunogenicity of a combined yellow-fever-measles freeze dried vaccine with each yellow-fever and measles separate administration. Children were divided in 2 populations 4-8 and 12-24 month old. 249 were controlled for measles (inhibition of hemagglutination) and yellow-fever (seroneutralization) antibodies. Seroconversion rates for measles were 82% when administrated before 9 months and 100% when given in 12-24 months period. Measles GMT is similar whatever the schedule or the age group; so, early vaccination does not impair the immunogenetic response. Moreover, 96% of the children vaccinated before 9 months still have detectable measles protective antibodies 8 months after. Among the initially seronegative children, the yellow-fever response is satisfactory with 92 to 96% seroconversion rate and post-immunization GMT ranging 16.5 to 29.5 without any statistical difference between the vaccine and age groups. The safety of the combined yellow-fever-measles vaccine is assessed by the rare number of reactions which are equivalent with the normally expected reactions with each vaccine administered separately. The results demonstrate the satisfactory immunogenicity and safety of the combined yellow-fever-measles vaccine. Combine yellow-fever-measles vaccination could help to improve the feasibility of EPI.

Age Factors↗

PubMed1991

Pharmacokinetics of pyrimethamine in healthy young volunteers using a new solid phase extraction/HPLC method.

The single dose pharmacokinetics of pyrimethamine were determined in 12 healthy young volunteers using a newly developed fully automated analytical system which combines liquid solid extraction on disposable extraction columns and high performance liquid chromatography. This technique is highly sensitive (detection 1 ng/ml) and reproducible. Following a 50mg dose of the drug, the plasma concentration peaked at 0.48 0.13 g/ml (msd) and was attained 2.5 hours (median value) post dosing. Thereafter, the plasma level of pyrimethamine decreased slowly, the level at 336 hours after administration being still about 40 ng/ml. The area under the plasma concentration-time curve (AUC0-inf) was 56.8 18.4 h.mg/ml. The volume of distribution Vd was: 2.42 1.25 l/kg and the total clearance: 15.55 4.48 ml/h/kg. Urinary excretion represented about 20% to 40% of the dose after seven days of the administered dose.

Adult↗

PubMed1991

[Short treatment of hepatic amebiasis by tinidazole. Apropos of 10 cases].

Ten cases of hepatic amoebiasis are notified in Bamako during 14 months among hospitalized adults. The diagnosis has aimed from clinical signs, specific antibodies seen through hemagglutination and echography. These patients are treated by tinidazole: 2 g/day in unique dose during 3-9 days. The duration of treatment depends on clinical evolution. In any cases the recovery is obtained within subsequent range from 1 to 9 months. This leading is compared with other treatments proposed in the literature. The briefness of treatment, its quick efficacy and the absence of secondary effects have helped to reduce the duration of stay in hospital and its cost. A short recovery by tinidazole is proposed as tentative treatment against hepatic amoebiasis in rural area's medicine.

Adolescent↗