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Query: UMLS:C0042961 (volvulus)
 4,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Data are presented on microfilaraemia in 191 Yanomami Amerindians from two areas of Venezuela's Upper Orinoco Basin, where an endemic focus of onchocerciasis has been recently detected. Onchocerca microfilariae were found in the blood of 12.6% of the persons examined. In the village with the higher number of examined individuals (N = 162), the prevalence of microfilaraemia in the age groups covaried with the prevalence of microfilariae in the skin and with the parasite load (mf/mg of skin). A positive correlation was found between age and these three variables. The prevalence of Onchocerca microfilaraemia in the Upper Orinoco focus is high, and may be related to the ability of the strain to invade the blood stream. Morphobiometric characteristics of the Onchocerca microfilariae isolated from human blood are similar to those of O. volvulus fixed in formalin from skin and from the uterus of female O. volvulus worms. All have a very short cephalic space. Comparisons with the entity from the Upper Caura river designated as Microfilaria bolivarensis were also made. It was concluded that there are no valid biometric differences in thick blood smears between microfilaria bolivarensis and microfilaria of O. volvulus from the Upper Orinoco deme. A more striking difference may be in the concentration of microfilariae observed in the blood, which in one case of mf. bolivarensis was more than forty times the highest number recorded for microfilaria O. volvulus in Parima.
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PMID:Onchocerciasis in Venezuela: prevalence of microfilaraemia in Amerindians and morphological characteristics of the microfilariae from the Upper Orinoco Focus. 649 85

Improved methods for diagnosis of onchocerciasis are needed. We have recently identified immune complex-associated parasite antigens in sera from onchocerciasis patients. The goal of this study was to produce monoclonal antibodies to these antigens that might be used in antigen detection assays. Two monoclonal antibodies (OV-1 and OV-5) that bind to parasite antigens in immunoblots of PEG-precipitated immune complexes from human onchocerciasis sera and to corresponding antigens in adult worm extracts and excretory-secretory products were produced. The target epitopes of the monoclonals are heat stable, resistant to trypsin, and destroyed by Pronase. The two monoclonals produce similar but not identical patterns of binding to immunoblots of Onchocerca volvulus adult worm antigen with major bands at 43-47, 58-63, and 70 kDa. OV-1 and OV-5 appear to bind to two distinct but closely related epitopes, neither of which is phosphorylcholine. Immunoelectron microscopy showed that the epitopes recognized by these monoclonals are widely distributed in adult female worms, but concentrated in the uterus and intestine. Antigen assays based on these antibodies detected parasite antigen in 9 of 14 sera from onchocerciasis patients, but significant background signal was detected in some nonendemic human sera. Thus, although this study has provided new information on parasite antigens in sera from onchocerciasis patients, additional work will be needed to achieve the goal of producing a sensitive and specific antigen diagnostic test for onchocerciasis.
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PMID:Onchocerca volvulus: monoclonal antibodies to immune complex-associated parasite antigens. 769 Jul 12

A review of displacements and surgery of the large colon is given on the basis of two cases. A four-year-old Dutch Warmblood mare was referred, one week before foaling, for colic of twelve hours duration. At rectal palpation a large uterus was found, but no cause for the colic. Laparotomy revealed a colonic volvulus and resection of about 75% of the large colon was necessary. A dead foal was born five days postoperatively, but the mare recovered well. A nine year-old Dutch Warmblood stallion with a history of frequent colic had been treated for nephrosplenic entrapment three times. Resection of the left part of the colon was performed successfully to prevent another entrapment.
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PMID:[Displacement and resection of the ascending colon in the horse: a literature review on the basis of 2 cases]. 819 85

Immunization of chimpanzees with radiation-attenuated infective 3rd-stage larvae (L3) of Onchocerca volvulus did not induce strong protective immunity against a subsequent challenge infection; only 1 out of 4 immunized animals remained non-patent (i.e. microfilariae-negative) after challenge, and may have been protected. However, during immunization and before challenge, a broad range of adult O. volvulus-derived antigens (OvAg) and also uterus-derived OvAg were recognized by circulating antibodies; moreover, the repertory of antigens recognized increased further in subsequently patent animals after challenge, particularly in the range of M(r) 12-42 kDa. In the immunized and non-patent chimpanzee, by contrast, serological recognition of uterus-derived OvAg with M(r) 14 kDa and 105 kDa disappeared by 19 months post-challenge (p.c.). During immunization, Acanthocheilonema viteae L3 antigens of M(r) 11-12 kDa were strongly recognized only by the non-patent animal, suggesting that recognition of these antigens may have supported resistance to the subsequent challenge infection. In immunized chimpanzees, a substantial increase in the cellular reactivity to OvAg was induced; this, however, declined by 19 months p.c. to levels similar to those seen prior to immunization. At that time, 3 out of 4 immunized animals were patently infected. The effect of exogenous cytokines on in vitro-reactivity of PBMC to OvAg was examined. Addition of exogenous IL-2 alone, IFN-gamma alone, and IFN-gamma in combination with IL-2, did not augment net cellular responses to OvAg by PBMC from infected and control chimpanzees. In the presence of IL-4 alone, IL-6 alone, IL-2 with IL-4, IL-2 with IL-4 and IFN-gamma, or IL-2 with IL-4 and IL-6, the net cellular reactivity to OvAg increased significantly in patent chimpanzees and reached levels similar to non-patent animals. Thus, non-patent chimpanzees maintain high cellular reactivity to OvAg and in vitro cellular unresponsiveness to OvAg on the part of patent chimpanzees is reversible after addition of several cytokines which act individually or synergistically.
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PMID:Experimental onchocerciasis in chimpanzees: cellular responses and antigen recognition after immunization and challenge with Onchocerca volvulus infective third-stage larvae. 835 1

A major antigen recognized by human sera in Onchocerca volvulus infections is a parasite eggshell protein. The cDNA clone for this antigen was isolated from a lambda gt11 O. volvulus cDNA library using antisera from patients with high microfilarial counts. Sequence analysis of the cDNA clone predicts a polyglutamine repeat near the 5' end of the cDNA, and a motif of four arginines near the 3' end, reminiscent of that found in many regulatory proteins. The cDNA was subcloned into a yeast expression vector and reagent quantities of recombinant antigen produced in Saccharomyces cerevisiae. Antisera produced to the recombinant purified protein localized the antigen to the eggshell of developing microfilariae within the adult female uterus. No other sites of Oveg1 expression were noted in adult worms, but labeling was seen in internal membrane structures of L3 larvae. Sera from infected chimps recognized Oveg1 only after infections became patent. Sera from infected humans showed reactivity to Oveg1 that varied from 39 to 95%, depending upon the geographic location.
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PMID:Onchocerca volvulus: identification and characterization of an immunogenic eggshell protein (Oveg1). 854 85

The distribution of an Onchocerca volvulus ankyrin, designated E1, was studied in different O. volvulus stages and other helminths by immunohistochemistry using rabbit antibodies raised against the recombinant E1 protein. In adult O. volvulus the protein designated E1 was localized to the extracellular clefts as well as to the cytoplasm adjacent to the cell membrane in the area of the basal labyrinth in hypodermis, intestine and uterus and to a lesser extent in oviduct and vas deferens. Neuronal cell bodies were also labelled. No labelling of the basal laminae, muscles or epithelia of ovary or testis was observed. Detection of the E1 protein was associated with embryonic development. Germ cells and early morulae showed no reaction; labelling was first seen in late morulae, corresponding to the stage of gastrulation, and increased in the following embryonic stages. In microfilariae the nerve ring and the cephalic space, which represents the anterior nerve-enriched portion of the body, were labelled. In third-stage larvae of O. volvulus labelling was associated with the hypodermis, and in those of Anisakis sp. the cytoplasm adjacent to the membrane of the excretory gland cell and the basal labyrinth of the hypodermis were labelled. Following anthelminthic treatment a disruption of the labelling pattern of the E1 protein was observed in adult O. volvulus with leakage of the protein into neighbouring areas. Damage to the worm was associated with reduction and finally loss of E1 protein labelling. No E1 protein was detected in dead adult worms, embryos or microfilariae. Labelling of the same organs was observed in 8 other Onchocerca species and in several other nematodes, but no reaction was seen in trematodes. The results indicate that the EI protein is associated with neuronal structures of O. volvulus, that its presence is developmentally regulated and that it has cross-reactive homologues in other nematodes. The results suggest that E1 is a functional protein. It may be useful for the assessment of parasite damage and death as well as in the characterization of the filarial nervous system.
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PMID:Immunohistological studies on an Onchocerca volvulus ankyrin (EI). 891 40

A yeast (Saccharomyces cerevisiae) expression system has been adapted to produce reagent quantities of a major Onchocerca antigen, Ov33. Using a pool of monoclonal antibodies produced against third-stage larvae, a cDNA library constructed from adult O. volvulus worms was screened. Twenty-seven cDNAs were isolated, two of which had sequence homology to Ov33, a putative aspartyl protease inhibitor, which is the immunodominant antigen of O. volvulus. These cDNAs were expressed at high levels intracellularly or through the secretory pathway of S. cerevisiae. Localization studies using antisera produced against purified recombinant protein demonstrated that Ov33 is a very abundant parasite protein present in the hypodermis, muscle, and uterus of female worms, as well as in embryonic microfilariae. The soluble recombinant protein secreted by yeast (C71) demonstrated inhibitory activity against the aspartyl protease pepsin. Antibodies to the recombinant protein-mediated leukocyte adherence to and killing of skin microfilariae. The sensitivity of a diagnostic test using recombinant Ov33 was evaluated using sera from 441 patients. The mean sensitivities for the two recombinant constructs, C27 and C71, were 82.2% and 85.4%, respectively. The combined sensitivity using both recombinant proteins was 94%.
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PMID:Characterization of a recombinant Onchocerca volvulus antigen (Ov33) produced in yeast. 939 7

Prostaglandins exhibit regulatory effects on the vascular and immune system. Prostaglandin E(2) (PGE(2)) modulates T helper (Th) cell and effector cell functional reactivity, thereby promoting Th2 responses. We found significant expression of PGE(2) in male and female Onchocerca volvulus. Using immunohistology, PGE(2) was predominantly detected in the hypodermis of adult O. volvulus, the metabolically most active tissue of the filaria. In contrast, the muscles were PGE(2)-negative and the epithelia of intestine and uterus and male genital tract showed only weak staining. Oocytes were well labeled whereas embryos and sperms did not react. Less pronounced PGE(2) staining was observed in some dermal microfilariae. The expression of PGE(2) was found independent of antifilarial (ivermectin) as well as anti-endobacterial (doxycycline) treatment of O. volvulus-infected patients. PGE(2) was also demonstrated in extracts of adult worms by high-performance liquid chromatography-mass spectrometry. Release of PGE(2) from live or moribund filariae can affect the host s metabolism and immune response in favor of the filarial parasite.
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PMID:The filarial parasite Onchocerca volvulus generates the lipid mediator prostaglandin E(2). 1651 82

In this case report, we describe a pregnant female patient at 27 weeks' gestation with a rare complication of volvulus. Her initial symptom was acute cramping pain of the lower right abdomen. Surgical intervention was performed under the impression of peritonitis. Pathologic diagnosis revealed volvulus of the mid ileum. The remainder of her pregnancy was uneventful. The physiologic changes of pregnancy may predispose the parturient to bowel obstruction due to compression of the gravid uterus against the intestine. If volvulus is suspected, then emergent surgery should be performed. Delays in treatment may result in septic shock and even death. We present this case to remind obstetricians of such rare causes of acute abdomen during pregnancy.
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PMID:Volvulus in pregnancy: a diagnostic dilemma. 1738 80

A case of intestinal volvulus in both the sigmoid colon and cecum in a pregnant woman suffering from severe constipation is reported herein. The fetus was dead and the mother developed acute shock. The twisted sigmoid colon coiled twice around the uterus and was perforated. The mother died 10 h after the onset of severe abdominal pain. Volvulus should be considered when examining severe abdominal pain in a pregnant woman with a history of severe constipation. Early suspicion together with prompt intervention will minimize maternal and fetal morbidity and mortality of this rare complication of pregnancy.
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PMID:Perforated colon volvulus coiling around the uterus in a pregnant woman with a history of severe constipation. 1784 39


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