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C Combes

Publications and source records attributed to C Combes.

At least 55 records · Page 3Linked to original sources
PubMed1992

Relocation of Schistosoma mansoni in the lungs and resistance to reinfection in Rattus rattus.

The localization of adult Schistosoma mansoni originating from Guadeloupe (West Indies) was analysed in the natural host Rattus rattus in experimental and natural infections. A transfer of schistosomes from the porto-mesenteric system to the lungs occurs between the 4th and the 20th weeks post-infection, with a peak between 4 and 8 weeks; it should be noted that the worms start laying eggs at 4 weeks post-infection. In both experimentally and naturally infected R. rattus the relocation of schistosomes in the lungs is correlated with the total worm burden. Between 6 and 12 weeks post-infection some adult worms and numerous eggs are trapped in the liver. A high mortality in the worm population coincides with the migration of the parasites from the porto-mesenteric veins to the lungs. In re-infected R. rattus a relationship appears between the presence of schistosomes in the lungs and resistance to reinfection. It is concluded that, as already postulated previously in mice, resistance to re-infection in the natural host R. rattus is at least partly correlated with the hepatic pathology caused by the schistosomes of the primary infection.

Animals↗
PubMed1992

Identification of Schistosoma mansoni, S. rodhaini, S. bovis, S. haematobium, and S. intercalatum cercariae using segmentation analysis.

Cercariae of five species of schistosomes identified with certainty were fixed in boiled alcohol and mounted in glycerol-alcohol mixture. The cercarian body (Cbl) and tail-furcae lengths (Ctl) were measured, the values of which were treated using a computer. Even mean values allowed partly identification of the present species, the segmentation analysis gave better informations for separating any cercaria taken at random, with a given probability (p). Thus, five classes (A, B, C, D, E) have been established: class A: Cbl > 139 microns and Ctl, > 236 microns, p = 0.59 to be considered as S. bovis; class B: Cbl > 139 and Ctl < 236, p = 0.86 to be considered as S. haematobium; class C; Cbl < 114 microns, p = 0.75 to be considered as S. intercalatum; class D: 114 < Cbl < 125 microns, p = 0.57 to be considered as S. mansoni; class E: 125 < Cbl < 139 microns, p = 0.57 to be considered as S. rodhaini. Two groups of schistosome have been established on basis of cercarian morphometry with S. intercalatum, S. mansoni and S. rodhaini from one side, S. haematobium and S. bovis to the other side.

Animals↗
PubMed1991

[Uterine phlebography in pelvic venous stasis].

Pelvic veins opacification is very helpful in the diagnosis of vascular pelvic pain. First applied to intrauterine vascularisation and hypoplasia research, hysterophlebography allow the venous side of stasis to be obvious. 1) Normally, a fine intra-parietal network draining in intrauterine peripheric vein (arcuate network) is patterned by the contrast medium. For that 4 vessels roots are leaving: 2 lumbo-ovarian pedicles joining uterine venous side und tubal veins and extending over lumbo-ovarian pedicle; 2 uterine pedicles resulting from 2 uterine veins and receiving vesical veins located in the base of broad ligament. Contrast medium empties very quickly and almost the whole uterus emptying is lasting less than 10 seconds. 2) From a pathological point of view: a) in stasis, intrauterine veins pattern features are: intra-parenchymatous pictures of dilated venous network, local alterations pictures often secondary to thrombosis (9/10 on the left side) with intra-parenchymatous stasis and oblique anastomatic main vessels characterizing uterine veins thrombosis, more than 20 seconds emptying delay. Hysterographic and phlebographic times take advantage to be paired by visualizing mucous lesions (hypoplasia and polyp. endocervical and corporeal) in intra-parenchymatous stasis phenomena. b) Extrauterine stasis signs are characterized by preferentially right pedicles dilatation. Standing in upright position enhances stasis (proclive radiographies at 70 degrees). Dilatation is particularly located at the base of the broad ligament and gives to uterine veins with wide smeets a flexuous feature with wide contrasted clusters. Hence here emptying is slow and belayed.

Edema↗
PubMed1991

[Uterine phlebography in pelvic venous stasis].

Pelvic veins opacification is very helpful in the diagnosis of vascular pelvic pain. First applied to intrauterine vascularisation and hypoplasia research, hysterophlebography allow the venous side of stasis to be obvious. 1) Normally, a fine intra-parietal network draining in intrauterine peripheric vein (arcuate network) is patterned by the contrast medium. For that 4 vessels roots are leaving: 2 lumbo-ovarian pedicles joining uterine venous side und tubal veins and extending over lumbo-ovarian pedicle; 2 uterine pedicles resulting from 2 uterine veins and receiving vesical veins located in the base of broad ligament. Contrast medium empties very quickly and almost the whole uterus emptying is lasting less than 10 seconds. 2) From a pathological point of view: a) in stasis, intrauterine veins pattern features are: intra-parenchymatous pictures of dilated venous network, local alterations pictures often secondary to thrombosis (9/10 on the left side) with intra-parenchymatous stasis and oblique anastomatic main vessels characterizing uterine veins thrombosis, more than 20 seconds emptying delay. Hysterographic and phlebographic times take advantage to be paired by visualizing mucous lesions (hypoplasia and polyp. endocervical and corporeal) in intra-parenchymatous stasis phenomena. b) Extrauterine stasis signs are characterized by preferentially right pedicles dilatation. Standing in upright position enhances stasis (proclive radiographies at 70 degrees). Dilatation is particularly located at the base of the broad ligament and gives to uterine veins with wide smeets a flexuous feature with wide contasted clusters. Hence here emptying is slow and belayed.

Female↗
PubMed1990

[Where do the parasites of man come from?].

The Hominids have come in contact, over the last few million years, with the infective stages of many parasites which had up to then evolved in non Primate hosts; this is because Hominids have occupied multiple environments and acquired diversified behaviour. The high number of these lateral transfers explains the multiplicity of current human parasitic diseases whereas their youth on an evolutionary scale accounts for the seriousness of most of these diseases. The basic questions arising from the exceptional opportunities offered to parasites by the evolution of the human lineage concern: the precise role played by human behaviour, the mechanisms of alterations in specificity, the identity of the original host phyla, the dynamic and genetic consequences for parasites, the relationship with the evolutionary history of the ancestors of Homo sapiens sapiens; for instance, it is suggested that man's mastery of fire, allowing him to cook his food, dramatically reduced his contamination by certain parasites and that this contributed to the subsequent success of Hominids.

Animals↗
PubMed1990

Genetic variability in the compatibility between Schistosoma haematobium and its potential vectors in Niger. Epidemiological implications.

A populational study of the compatibility between Schistosoma haematobium and its potential vectors has been carried out in the Niger, confronting samples of S. haematobium populations from three epidemiologic foci with Bulinus populations originating from the same focus (sympatric infection) and with Bulinus populations from other foci (allopatric infections). The three transmission foci selected were irrigation canals in ricefields along the Niger river where one finds: Bulinus truncatus rohlfsi, Bulinus globosus, Bulinus forskalii and Bulinus senegalensis; temporary pools in the Sahel area where one finds B. truncatus and B. senegalensis; permanent pools of the "guelta" type in Sahara area where only B. truncatus occurs. As a compatibility test, the snail infection test was selected, with particular emphasis on optimising its reliability. Snail-infection experiments showed that B. truncatus and B. senegalensis are very good potential vectors, with infection rates ranging between 71.5 and 85.9%. B. globosus and B. forskalii, on the other hand, are totally incompatible. The mean infection percentages in the sympatric and allopatric combinations carried out with the S. haematobium-B. truncatus couple were very similar. This character strongly suggests a lack of isolation in schistosome populations and a circulation of the parasite genome through the mobility of infected human populations (Peuls and Touaregs) in Sahel zone. This study, in relation with snail surveys carried out in parallel, shows that the main types of aquatic environments on the Niger act as high risk areas for schistosome transmission.

Adolescent↗
PubMed1989

[Compressive vertebral hemangioma. The contribution of imaging technics to diagnosis and pretherapeutic evaluation].

From a serie of ten cases of compressive vertebral hemangiomas (H.V.C.), the interest of different imaging methods was evaluated. CT scan and M.R.I. were the best imaging modalities in most cases. A CT guided biopsy was necessary in three cases to differentiate from metastasis. Angiography permitted to establish the vascular patterns and to evaluate the usefulness of embolization performed in six cases.

Adolescent↗
PubMed1989

MRI in the diagnosis of so-called pituitary apoplexy: seven cases.

The authors describe seven cases of pituitary adenoma with acute neurological symptoms (the so-called pituitary apoplexy), which were examined by magnetic resonance imaging (MRI). Four patients underwent surgery and the diagnosis of pituitary adenoma was histologically confirmed. In 3 patients, conservative treatment was decided and serial MRI examinations showed progressive decrease in size of the tumour, leading in one case to an empty sella. Computerized tomography (CT) was positive in all 7 cases, but less contributive than T1-weighted MRI images both for tumoral volume determination and detection of intratumoral haemorrhage. Although theoretical problems may arise concerning the diagnosis of acute intratumoral bleeding at an early stage, the authors emphasize the value of MRI in showing the extension of the tumor into the retroclival cistern and the cavernous sinus, especially when surgery is not performed in the acute period.

Acute Disease↗
PubMed1988

Up to what point are cercariogenesis and sporocystogenesis reversible in schistosomes?

A study of larval development of Schistosoma haematobium in the snail Planorbarius metidjensis infected by transplanted sporocysts showed that some embryos in daughter sporocysts have characters intermediate between cercariae and sporocysts. These embryos are interpreted to be nearly mature cercariae that have partially reverted to be secondary sporocysts. If this explanation is correct, it would mean that the embryos which develop within trematode daughter sporocysts can differentiate either into cercariae or into a new generation of sporocysts, but originate from a single type of germinal cell.

Animals↗
PubMed1987

Effect of praziquantel on larval stages of Schistosoma japonicum.

The effect of praziquantel on S. japonicum mother sporocysts, daughter sporocysts and cercariae was studied. At concentrations of 3 X 10(-7), 3 X 10(-6) and 3 X 10(-5) M and treatment times of 24 or 48 h, mother and daughter sporocysts and young cercarial embryos were not affected but nearly mature cercariae were killed and dissociated. The resistance of young cercariae could support the suggestion that the primitive cercarial epithelium arises from the sporocyst tegument. Treatment with praziquantel always stopped cercarial emission; this cessation lasted for a few days with the lowest concentration and for up to 25 d with the highest. The duration of treatment slightly affected the pattern of reappearance of cercariae but markedly affected the long-term reduction in numbers. Free cercariae treated with praziquantel lost their tails in 10 to 60 min, depending on the concentration.

Animals↗
PubMed1987

Genetic variability of Schistosoma bovis cercarial production according to miracidial dose.

Cercarial production related to miracidial dose variation with Schistosoma bovis strains from Sudan and Spain in Bulinus truncatus from Tunisia was studied. Results showed that an increase in the miracidial dose proposed to the host-mollusc (1 and 5 miracidia) gave rise to a decrease in cercarial productivity of Sudanese S. bovis and to an increase for Spanish S. bovis. It is concluded that this response difference to the miracidial dose variation depends on genetic characters peculiar to the parasite strain and represents a new aspect of genetic variability of schistosome populations.

Analysis of Variance↗
PubMed1987

[Comparative analysis of the rhythm of cercariae emergence in three strains of Schistosoma bovis (trematoda: Schistosomatidae)].

A comparative experimental study of the rhythmic shedding of three geographic strains of Schistosoma bovis cercariae (Sardinian, Sudanese and Spanish) by Bulinus truncatus showed a significant difference in the emergence patterns. The results support the existence of a genetic variability of the emergence rhythms. The origin of the variability is discussed and could be found in the pastoral practice and the ecological characteristics of the different transmission foci.

Animals↗
PubMed1986

Comparative analysis of the Schistosoma mansoni and Schistosoma bovis cercarial production under the influence of praziquantel.

Snails infected with Schistosoma mansoni and S. bovis and fed with a food-Praziquantel mixture stop shedding cercariae for several days. The cercarial production restarts at different levels after stopping treatment: for some Biomphalaria glabrata, the restarting phase of production reaches a high level whereas for other B. glabrata and all of the P. metidjensis, the level of production remains low. Histological studies revealed that at the exact moment of this treatment, there is a total destruction of many nearly mature cercariae whereas the young cercarial embryos and the tegument of the sporocyst remain unharmed. When treatment stops, there is a pronounced proliferation of third-generation sporocysts (Sp III) which invade the available space of the snails' digestive gland.

Animals↗
PubMed1986

Schistosoma mansoni: comparison of a Caribbean and African strain and experimental crossing based on compatibility with intermediate hosts and Rattus rattus.

To elucidate changes relative to compatibility with intermediate and definitive hosts affecting Schistosoma mansoni since it was introduced to the New World, the compatibility of S. mansoni from Africa (the Cameroons), from the Caribbean (Guadeloupe), and those resulting from experimental crosses with the gastropods Biomphalaria glabrata and B. pfeifferi has been studied. Results show that S. mansoni, regardless of its origin or its usual snail host, always infects B. pfeifferi more successfully than B. glabrata. The success rate with B. pfeifferi is 100% with 5 miracidia of S. mansoni from Guadeloupe and 97% with 5 miracidia from the Cameroons. On the other hand, in B. glabrata infection rate was 54% with 5 miracidia from Guadeloupe and 0% with 5 miracidia from the Cameroons (a rate of 19% is reached when using 10 miracidia). Hybrid miracidia infect B. pfeifferi and B. glabrata with a success rate of 60 and 86%, respectively, which are intermediate between those of the parent strains. Studies of S. mansoni development in Rattus rattus show that there is better infectivity and survival for the Caribbean strain than the Cameroon strain: the percentage worm recovery 4 weeks after exposure in 34% for S. mansoni from Guadeloupe, 14% for S. mansoni from the Cameroons, and 31% for the hybrids. The mortality rate between 4 and 12 weeks after exposure is 51% for S. mansoni from Guadeloupe, 87% for S. mansoni from the Cameroons, and 31% for the hybrids.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗