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At least 361 records · Page 20Linked to original sources
PubMed1999

Variation in microfilariae and infective stages of two types of Wuchereria bancrofti from the Thai-Myanmar border.

Comparative morphometric and morphological studies of microfilariae and infective stages were undertaken in nocturnally periodic and subperiodic Wuchereria bancrofti. For microfilariae, the body dimensions of nocturnally periodic (NP) were significantly smaller than nocturnally subperiodic (NSP), i.e., body length 268.03+/-14.75 microm (NP), 307.61+/-11.52 microm (NSP); cephalic space length 4.21+/-0.62 microm (NP), 5.32+/-0.79 microm (NSP); head to nerve ring 49.39+/-5.43 microm (NP), 57.40+/-4.46 microm (NSP); innenkörper length 33.05+/-5.89 microm (NP), 44.02+/-8.71 microm (NSP); cephalic space width 4.28+/-0.59 microm (NP), 6.04+/-0.68 microm (NSP); body width at nerve ring 5.01+/-0.57 microm (NP), 7.45+/-0.75 microm (NSP). The number of nuclei between the cephalic space and nerve ring of NP (66.67+/-5.19) was also significantly less than in NSP (94.74+/-6.95). For infective stages, the body dimensions of NP were significantly smaller than NSP, i.e., body length 1632.50+/-131.48 microm (NP), 2002.63+/-222.60 microm (NSP); head to nerve ring 103.09+/-7.47 microm (NP), 122.44+/-9.62 microm (NSP); head to oesophago-intestinal junction 567.69+/-94.84 microm (NP), 666.75+/-110.08 microm (NSP); body width at oesophago-intestinal junction 23.15+/-1.55 microm (NP), 26.78+/-1.62 microm (NSP). It is too early to infer the NP type as an additional sibling species of W. bancrofti but it is reasonable to treat it as a new variety and additional work is needed to clarify its status.

Animals↗
PubMed1992

[Observation on the early development of inoculated Brugia malayi microfilariae in mosquitoes].

This paper reports the early development and variation of inoculated Brugia malayi microfilariae in 3 groups of mosquitoes, i. e. young Anopheles sinensis, young Culex quinquefasciatus and old Cx. quinquefasciatus. Significant differences were observed among these groups. Sixty hours after inoculation, the percentage of normally developing filarial larvae in young An. sinensis was 72.3%; the percentage of melanized microfilariae in young Cx. quinquefasciatus was 75.4% and the percentage of filarial larvae which developed abnormally or remained in diapause status in old Cx. quinquefasciatus was 67.1%, each being much higher than that in the other groups. It was suggested that the immune competence of the mosquitoes had influence upon the filarial development. The intensity of the immune response not only varied with the species, but also diminished with the aging of mosquitoes.

Aging↗
PubMed1991

Synthesis of 5-keto-5-oxime derivatives of milbemycins and their activities against microfilariae.

Starting from milbemycin D (1), milbemycin A4 (2) and milbemycin A3 (3), a series of 5-keto-5-oxime derivatives were synthesized by selective oximation at the alpha,beta-conjugated carbonyl function of the 5-ketomilbemycins (4-6). The activities of the synthesized compounds were studied in dogs naturally infested with microfilariae of Dirofilaria immitis. The 5-keto-5-oximes of milbemycin D (7), A4 (8) and A3 (9) had quite high efficacy to control the microfilariae and more potency than their parents, while the 5-O-acyl oximes (11-15) also exhibited high activity.

Animals↗
PubMedDate not supplied

Description of a microfilaria from an umbrella cockatoo (Cacatua alba) and an unsuccessful attempt to infect mosquitoes (Culex pipiens pipiens).

Unidentified microfilariae circulating in the blood of an umbrella cockatoo (Cacatua alba) are described. They are ensheathed, measure 102-152 microns long and 2-3 microns in diameter, and have four distinct and consistent gaps in the nuclear column. Attempts to infect mosquitoes (Culex pipiens pipiens) with the microfilariae were unsuccessful.

Animals↗
PubMedDate not supplied

[Microfilariae in vaginal exudates from Argentinian apes].

The finding of Dipetalonema gracile larves in vaginal content of capuchin monkeys (Cebus apella) was reported. The sizes of microfilarias, which did not present capsule, were 110-160 microns long and 4-5 microns wide. Microfilarias did not find in peripheral blood. Assuming that the cycle of this worm is not yet elucidated, the authors postulate that the presence of larves in the female genital tract could relate with venereal transmission.

Animals↗
PubMed1991

Fine structure of microfilariae in the skin of onchocerciasis patients after exposure to amocarzine.

Transmission electron microscopy was used to demonstrate the effects of amocarzine (CGP 6140) on the fine structure of Onchocerca volvulus microfilariae (mf) in skin biopsies from patients treated orally in Guatemala or transepidermally exposed in Liberia. After 6-10 hours exposure to the drug most mf did not show any alterations and only a few mf contained increased numbers of vacuoles in the cytoplasm and clefts between cuticle and hypodermis. At 20-48 hours after treatment most of the mf showed distinct signs of damage. Most frequently seen was disintegration of the cytoplasm of the afibrillar portion of the muscle cells. Some mf showed also disintegration of the myofilaments and of the internal structure of the mitochondria in the muscle cells. Other signs were progressive separation of the cuticle from the hypodermis, increase of intracellular vacuoles and clefts and in some mf condensation of the cytoplasm. The type and the site of the morphological alterations were the same after both forms of amocarzine administration. The degree of morphological changes increased with the length of time of exposure to the drug. Microfilariae with morphological alterations were nearly always surrounded by adherent host cells, mostly eosinophils and macrophages.

Administration, Cutaneous↗
PubMed1990

Immunocytochemical localization of surface antigens in microfilariae of Wuchereria bancrofti.

Antigenic sites were localized on the surface structure (sheath and cuticle) of microfilariae of Wuchereria bancrofti using sera from microfilaraemic and amicrofilaraemic patients using antibodies associated to colloidal gold particles and transmission electron microscopy. No labeling was observed on the surface of intact parasites. Microfilariae without the sheath and isolated sheath were obtained by ultrasound treatment. Using these preparations labeling of the inner portion of the sheath was observed when sera from amicrofilaraemic patients were used. Labeling of the cuticle surface was observed mainly in the regions of the cuticular annulations.

Animals↗
PubMed1989

Electron microscopic studies on the effects of CGP 6140 and CGP 20376 on microfilariae and third stage larvae of Onchocerca volvulus.

Electron microscopic examination was used to assess the effects of CGP 6140 (proposed generic name: amocarcine) and CGP 20376 (proposed generic name: metobethiamide) on the fine structure of microfilariae and third stage larvae of Onchocerca volvulus after in vitro exposure to different concentrations of these compounds. The range of concentrations was selected according to the expected plasma levels that may be reached with these drugs. The microfilariae showed distinct effects on the muscle cells as myelin figures, vacuolisation and disintegration of the cytoplasm after both compounds. The third stage larvae showed the same effects on the muscle cells including changes in the mitochondria and the hypodermal tissue. In addition, the glandular esophagus demonstrated degenerative alterations of the cytoplasm and loosening of the cuticular lining after exposure to CGP 6140. CGP 20376 led to severe damage of the fibres of the nerve ring. No degenerative changes of the microtubuli were observed. Comparison of the morphological effects observed by electron microscopy with the reduction rates of motility and moulting recorded in the in vitro tests showed good correlation between these different parameters. The observed effect on the fine structure was the most sensitive parameter.

Animals↗
PubMed1989

[Observation on the intake of Brugia malayi microfilariae by Anopheles sinensis and host efficiency].

The experiments were carried out under the controlled conditions with temperature at 26 +/- 1 degree C and relative humidity 75-85%. The Brugian microfilariae from the peritoneal cavity of Mongolian jirds, mixed with rabbit blood, were ingested by Anopheles mosquitoes through the artificial membrane. The experimental data show that the number of microfilariae ingested is fewer than would be expected from the microfilarial densities in the blood meal. The linear regression shows their quantitative relation, Y = 0.61X-1.37. At the same time the host efficiency of Anopheles sinensis decreases with the increase of microfilarial number ingested. In case of the relationship between Brugia malayi and Anopheles sinensis, the survival rate of vector host is the chief factor influencing the decrease of host efficiency.

Animals↗
PubMed1977

Preliminary studies on the histochemical differentiation of strains of Onchocerca volvulus microfilariae in Togo.

Skin snips were taken from 75 people living in four villages of northern Togo. The 7824 microfilariae that emerged were examined by staining for the presence of acid phosphatase. Four distinct patterns of enzyme staining were observed, and descriptions of the stained microfilariae are given. The study confirms the view that a number of biological strains or variants of Onchocerca volvulus coexist in West Africa, and suggestions are made for further research that could result in the practical application of these observations in onchocerciasis control programmes.

Animals↗
PubMed1978

A simplified technique for counting onchocercal microfilariae in skin snips.

A new method for counting microfilariae in skin snips is described. The method, in which slide specimens are reconstituted after drying, is compared quantitatively with two existing methods that are used when the counting of microfilariae has to be postponed. Counts obtained by the new method were closely correlated with those taken in fresh specimens. Other advantages of the new method are discussed and its use in onchocerciasis field surveys is recommended.

Animals↗
PubMed1988

Analysis of glutathione-enhanced differentiation by microfilariae of Onchocerca lienalis (Filarioidea: Onchocercidae) in vitro.

Reduced glutathione (GSH), but not its oxidized form (GSSG), stimulated development of Onchocerca lienalis microfilariae to the late first-larval stage in vitro. The degree and frequency of development was dose-related with a peak of activity at 15 mM, a concentration that is similar to known intracellular levels of GSH. To determine the mode(s) of action of this multifunctional compound, other reducing agents (L-cysteine, dithiothreitol), cysteine delivery agents (N-acetyl-L-cysteine, L-thiazolidine-4-carboxylic acid, L-2-oxothiazolidine-4-carboxylic acid), cysteine analogues (S-methyl-L-cysteine, D-glucose-L-cysteine, cysteine ethyl ester), free-component amino acids of GSH (glutamic acid, cysteine, and glycine), a specific metabolic inhibitor of gamma-glutamyl synthetase (buthionine sulfoximine), and an inhibitor of gamma-glutamyl transpeptidase (gamma-glutamyl glutamic acid) were also tested at concentrations of 0.01-50 mM in this system. N-acetyl-L-cysteine at 1-5 mM and D-glucose-L-cysteine at 2.5-10 mM significantly enhanced development. In contrast to those worms maintained in GSH-supplemented medium, microfilariae exposed to GSH for only the first 24 hr showed no enhancement by day 7 in culture. Neither buthionine sulfoximine nor gamma-glutamyl glutamic acid at 0.01-35 mM inhibited the effects of 15 mM GSH or 1 mM N-acetyl-L-cysteine. Results indicate that GSH or other cysteine analogues possessing a free sulfhydryl group must be present in the extranematodal environment to support microfilarial differentiation in vitro.

Animals↗
PubMedDate not supplied

Microfilariae in laryngeal and pharyngeal brushing smears from a case of carcinoma of the pharynx.

Microfilariae were observed in May-Grünwald-Giemsa-stained brushing smears of the laryngeal and pharyngeal areas in a 35-year-old man with carcinoma of the pharyngeal wall and marked laryngeal edema. Liberation of microfilariae due to lymphorrhexis following severe lymphedema was considered to be the mechanism for the infestation of these sites, which has not been previously reported.

Adult↗
PubMed1979

[A method to detect microfilariae of Dipetalonema witei in the peripheral blood of mastomys natalensis (author's transl)].

A new cheap and time saving procedure is described for the detection of microfilariae of Dipetalonema witei in the peripheral blood of Mastomys natalensis. A special apparatus delivering an ether-air mixture is used to anesthetize the experimental animals for a short period in a very careful way and without side effects. The ether wapour induces a rapid shift of microfilariae within one minute from the lung to the peripheral blood.

Anesthesia, Inhalation↗
PubMed1979

Efficacy of avermectin B1a against microfilariae of Dirofilaria immitis.

Avermectin B1a given at a dose level of 0.05 or 0.1 mg/kg of body weight caused rapid removal of Dirofilaria immitis microfilariae from the blood of dogs with heartworm infections. If the adult worms were also killed with an arsenical (melarsoprol), the removal of microfilariae was permanent.

Animals↗