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Biomedical subjects

B Fried

Publications and source records attributed to B Fried.

At least 73 records · Page 4Linked to original sources
PubMed1996

Egg laying in vitro of Echinostoma caproni (Trematoda) in nutritive and nonnutritive media.

Egg laying in vitro was studied in Echinostoma caproni adults placed in 10 ml of nutritive or nonnutritive media for 48 h in petri-dish cultures maintained at 37 degrees C in an atmosphere containing 7.6% CO2. Maximal egg laying occurred within 24 h in the defined medium RPMI 1640. Egg laying was significantly greater in this medium than in McCoy's or Locke's solution. Eggs released into the RPMI medium were capable of producing miracidia that were infective to Biomphalaria glabrata snails. Fried and Huffman (1996) referred to a technique used to obtain eggs of Echinostoma caproni in the defined medium RPMI 1640, but details of the study were not given. No information is available on egg laying of echinostomes in vitro. Such information could contribute to a better understanding of egg release in digeneans and would also be helpful in the acquisition of eggs for biology and chemistry studies. Current techniques used to obtain echinostome eggs involve worm homogenization, teasing of eggs from the worms' uteri, or recovery of eggs from feces (see Idris and Fried 1996 for details). The purpose of this communication is to report on an efficient procedure for the acquisition of eggs of E. caproni after the placement of adult worms in the defined medium RPMI 1640. E. caproni adults were grown in ICR mice for either 17 (young worms) or 112 days (old worms) as described previously (Ursone and Fried 1995a). Worms were removed from the small intestines and rinsed rapidly in three changes of sterile Locke's solution containing penicillin (200 IU/ml) and streptomycin (200 micrograms/ml; Fried and Contos 1973). Worms were placed in culture media within 30 min of their removal from hosts. Nutritive media consisted of RPMI 1640 and McCoy's medium (Sigma, St. Louis, Mo.). Non-nutritive media consisted of Locke's or Locke's 1:1 (Ursone and Fried 1995b). All media contained antibiotics as described above.

Animals↗
PubMed1996

Rapid expulsion of the intestinal trematodes Echinostoma trivolvis and E. caproni from C3H/HeN mice after infection with Nippostrongylus brasiliensis.

The number of goblet cells in the small intestines of C3H/HeN mice increased rapidly following their infection with about 500 third-stage larvae (L3) of the intestinal nematode Nippostrongylus brasiliensis. The number of goblet cells reached its peak on day 9 postinfection (p.i.). Worm burdens in the hosts' small intestines were determined following a challenge infection with encysted metacercariae of the intestinal trematodes Echinostoma trivolvis or E. caproni on days 8 and 16 after primary infections with N. brasiliensis. All metacercariae of E. trivolvis or E. caproni used to challenge the hosts on day 8 p.i. were expelled. Considerable numbers of E. trivolvis (48.6%) and E. caproni (67.1%) remained in the intestines of hosts challenged with these echinostomes on day 16 p.i. All the controls used for E. trivolvis and E. caproni infections without primary infections with N. brasiliensis showed recovery rates greater than 70%. An enzyme-linked immunosorbent assay (ELISA) showed that the IgM titer rose remarkably and plateaued on day 11 p.i. No marked rise in the IgG or IgA titer occurred during the experiment. These results indicate that mucins increased by hyperplastic goblet cells associated with primary infections with N. brasiliensis are responsible for a rapid expulsion of the worms of the challenge infection with E. trivolvis or E. caproni from the mouse host.

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PubMed1996

Rapid expulsion of the intestinal trematodes Echinostoma trivolvis and E. caproni from C3H mice by trapping with increased goblet cell mucins.

Echinostoma trivolvis (Cort, 1914) adults were rejected from C3H mice by 15 days post-exposure, corresponding to the increase in the number of goblet cells. Homologous and heterologous infections with the allopatric species E. caproni (Richard, 1964) were used to confirm the effect of increased secretion of goblet cell mucins in rejecting metacercariae of challenge infections of E. trivolvis or E. caproni on days 10, 16 and 20 p.i. after primary infections of E. trivolvis metacercariae. Five-day-old juveniles of E. trivolvis and E. caproni, which were recovered from C3H mice or hamsters, were also used for challenge infections on day 10 p.i. The metacercariae and juveniles, which were challenged homologously and heterologously on day 10 p.i., were almost all expelled. The metacercariae of E. trivolvis, which were challenged homologously on day 16, were completely rejected, but only a few challenged metacercariae of E. caproni in heterologous infection were recovered. Considerable numbers of E. caproni were recovered when challenge infections with the metacercariae were done on day 20 p.i., while only a small number of E. trivolvis was recovered. All controls without primary infections showed a recovery rate of over 50% of the worms. These results indicate that increased secretion of mucins by hyperplastic goblet cells associated with primary infections of E. trivolvis may be responsible for the expulsion of worms challenged homologously with E. trivolvis and heterologously with E. caproni from the mouse host.

Animals↗
PubMed1996

Experimental infection of Helisoma trivolvis (Colorado strain) snails with cercariae of Echinostoma trivolvis.

A Colorado (CO) strain of Helisoma trivolvis resistant to miracidial infection, but susceptible to Echinostoma trivolvis cercarial penetration, was used to study encystment of cercariae released from naturally infected H.trivolvis (Pennsylvania strain). All 12 snails, 8-10 mm in shell diameter, each exposed to 25 cercariae and necropsied 1-4 days post-exposure were infected with between 9 and 19 cysts per snail (average 14). In all infectivity experiments, regardless of the size (age) of the Colorado strain snails used, encysted metacercariae were recovered from the kidney-pericardial region of experimentally infected snails within 24 h post-exposure. Snails exposed individually with 500 cercariae averaged 230 cysts per snail at 24 h p.i. Cercariae encysted at 6-8 h p.i., but not at 2 and 4 h p.i. Light microscopical observations of the cysts suggested that greater than 99% were viable. Metacercariae subjected to in vitro excystation in an alkaline trypsin-bile salts medium showed excystation rates of 60-85%. In conclusion, H. trivolvis (CO strain) is an excellent experimental second intermediate host for cercarial encystment of E. trivolvis.

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PubMed1996

Effects of the anthelmintics clorsulon, rafoxanide, mebendazole and arprinocid on Echinostoma caproni in ICR mice.

Female ICR mice, 5 to 6 weeks old, were exposed by stomach tube to 25 metacercarial cysts of Echinostoma caproni per mouse. At 14 days post-exposure, mice were fed by stomach tube clorsulon (1000 mg/kg, 500 mg/kg and 100 mg/ kg) or rafoxanide (50 mg/kg, 25 mg/kg and 5 mg/kg) dissolved in dimethylsulphoxide (DMSO) carrier and mebendazole (1000 mg/kg and 500 mg/ kg) or arprinocid (100 mg/kg and 50 mg/kg) suspended in a 2:1 polyethylene glycol (PEG)/DMSO carrier. All drugs were obtained from Merck Inc. (Rahway, New Jersey, USA) and only single dose regimes were used. Experimentally infected mice that served as controls received either DMSO or 2:1 PEG/DMSO carriers or were not given the carrier. Mice were necropsied 15, 16, 18 and 20 days postexposure to worms. Doses of 100 mg/kg of clorsulon and 50 mg/kg of rafoxanide were 100% effective in eliminating the echinostomes on day 1 post-administration of the anthelmintics. Mebendazole and arprinocid were ineffective in eliminating worms at 1 or 2 days post drug administration.

Adenine↗
PubMed1996

The expulsion of Echinostoma trivolvis from C3H mice: differences in glycoconjugates in mouse versus hamster small intestinal mucosa during infection.

Mucosal glycoconjugates were examined in C3H mice and in hamster small intestines infected with Echinostoma trivolvis and in uninfected rodents, using periodic-acid Schiff (PAS) and high-iron diamine-alcian blue (HID-AB) staining and three different fluorescein-conjugated lectins: Triticum vulgaris agglutinin (WGA), Helix pomatia agglutinin (HPA) and Griffonia simplicifolia agglutinin (GSA-II). Lectin-labelling by electron microscopy was also undertaken with WGA and HPA lectin-gold probes. HID-AB stain demonstrated that the most mature goblet cells of the mouse villi contain sulfomucins, whereas those of hamsters contain sialomucins. The expression of lectin-binding sites and the intensity of the lectin binding in the small intestines were changed by echinostome infection. Specific differences in the reaction to mucin glycoproteins were clearly observed between the mouse and hamster intestines infected with E. trivolvis; lectin-binding to hyperplastic goblet cells and crypts in the infected mice increased, while no marked increase in the number of goblet cells and reaction to the glycoconjugates were observed in the infected hamsters. These findings indicate that the expression of terminal N-acetyl-D-galactosamine, sialic acid and N-acetyl-D-glucosamine increased in mucins secreted from hyperplastic goblet cells associated with E. trivolvis infection in mice. No marked increase in these glycoconjugates occurred in hamster infections. These findings reflect clear differences in infectivity of E. trivolvis in C3H mice versus hamsters.

Animals↗
PubMed1996

Effects of high fat diets on worm recovery, growth and distribution of Echinostoma caproni in ICR mice.

The effects of high fat diets (HFDs) on the host-parasite relationship of Echinostoma caproni in ICR mice were studied. Two HFDs were used, one consisting of a customized high fat diet (CHFD) with 45% lipid in the form of cottonseed oil, and the second consisting of an egg yolk diet (EYD) from domestic hens' eggs, with 31% lipid. Controls for both diets consisted of mice fed a standard laboratory diet with 5% lipid. Mice were each fed 25 cysts of E. caproni by stomach tube and necropsied 2, 3 and 4 weeks postinfection (PI). The weight of mice on the CHFD declined significantly compared to mice on the control diet, but there was no significant decline in weight of mice fed EYD compared to the controls. Worm recoveries from mice on both HFDs were significantly less than those from control hosts. There was a significant decline in worm dry weight, body area and uterine egg counts in worms on HFD compared to those on the control diet. Worms from hosts on HFD were located more anteriad in the gut than those recovered from mice on the control diet.

Animals↗
PubMed1996

The expulsion of Echinostoma trivolvis: suppressive effects of dexamethasone on goblet cell hyperplasia and worm rejection in C3H/HeN mice.

C3H/HeN mice were infected with Echinostoma trivolvis metacercariae on day 0, given intramuscular injections of dexamethasone daily for 5 or 7 days, and necropsied on days 5, 8, 12, 15, 20 and 30 p. i. Controls consisted of mice that were infected with echinostomes, but were not treated with dexamethasone. Dexamethasone treatment caused a delay in worm expulsion from the small intestine of the hosts, and the increase in goblet cell numbers that occurred in untreated mice was markedly delayed in the treated mice. Mast cell number in the small intestine increased rapidly from just after day 5 p. i. and reached a peak on day 15 p. i. in both dexamethasone-treated and control mice, although the increase in cell numbers was delayed slightly in the dexamethasone-treated mice. The eosinophil number in the small intestine of dexamethasone-treated mice was suppressed until 8 days p. i. and then increased reaching a peak on day 12 p. i., although the number was about one half that of the control. As determined on day 12 p. i., the mean body area of worms from dexamethasone-treated animals was significantly greater than that of the controls. Histological examination of the small intestine showed that the goblet and Paneth cell hyperplasia seen in mice infected with E. trivolvis was suppressed by dexamethasone treatment. Transmission electron microscopy revealed no marked ultrastructural differences in the small intestine of the dexamethasone-treated and control mice except that the former had an increased number of intracristal granules in mitochondria, an increase in vesicles in the apical epithelial cells and an increase in amorphous bodies and autophagic vacuoles in the Paneth cells. These results indicate that dexamethasone treatment delayed the expulsion of E. trivolvis from the small intestine of the host mouse in association with the suppression of goblet cell hyperplasia and increase in the number of mast cells and eosinophils.

Animals↗
PubMed1996

Emergence of cercariae of Echinostoma trivolvis from Helisoma trivolvis under different conditions.

Release of Echinostoma trivolvis cercariae from naturally infected Helisoma trivolvis snails maintained under different laboratory conditions was studied. Infected snails were isolated for 1 hr in Stender dishes containing 5 ml of artificial spring water and the number of cercariae released during this time was recorded. Of the conditions tested, i.e., light versus dark, day versus night, volume of water, snail maintenance temperature prior to isolation, temperature during isolation, food versus no food, aeration of water, disturbance of water, and isolation in snail conditioned water, the only significant factors in the emergence of E. trivolvis cercariae were temperature related. Observations on cercariae released in vitro from isolated rediae maintained in Locke's solutions were in accord with the in vivo results.

Animals↗
PubMed1996

In vitro studies on intraspecific and interspecific chemical attraction in daughter rediae of Echinostoma trivolvis and E. caproni.

In vitro pairing and aggregation studies on daughter rediae of Echinostoma trivolvis and E. caproni were done at 22 degrees C in a Petri dish bioassay containing an agar substratum and a Locke's solution overlay. Pairing or aggregation was considered positive when rediae were in contact or within 1 mm of each other. Intraspecific and interspecific pairing or aggregation occurred in the bioassay when rediae were initially placed 5 or 10 mm apart. Movement of a single redia in the bioassay to a dialysis sac containing 1-10 rediae showed that intraspecific and interspecific pairing occurred in the absence of redial tactile stimulation. Movements of single rediae in the bioassay to agar plugs impregnated with redial excretory/secretory (ES) products occurred. The lipophilic fraction of the ES products was significantly more attractive than the hydrophilic fraction. The significance of redial chemical communication is not clear.

Animals↗
PubMed1995

The effect of dexamethasone on the course of Echinostoma caproni and E. trivolvis infections in the golden hamster (Mesocricetus auratus).

Golden hamsters (Mesocricetus auratus) were given intramuscular injections of dexamethasone and infected with Echinostoma caproni or E. trivolvis. All animals were necropsied on day 14 postinfection. Dexamethasone treatment at high doses resulted in increased parasite recovery. Decreased total white blood cell counts and decreased relative splenic weights were observed in corticosteroid-treated hamsters. Dexamethasone-treated animals also demonstrated significantly lower mean parasite dry weights for E. caproni. Specific serum IgG against the parasites was not detected in corticosteroid-treated hamsters on day 14 postinfection.

Animals↗
PubMed1995

An enzyme-linked immunosorbent assay for detecting anti-Echinostoma trivolvis (trematoda) IgG in experimentally infected ICR mice. Cross-reactivity with E. caproni.

An enzyme-linked immunosorbent assay (ELISA) utilizing surface glycocalyx-membrane crude antigen of adult Echinostoma trivolvis was developed for the detection of circulating anti-E. trivolvis IgG in experimentally infected ICR mice. An antigen concentration of 10.0 micrograms/ml was used, and it was possible to detect anti-E. trivolvis IgG at a dilution of 1/3,200. On day 10 postinfection (p.i.), all infected mice had anti-E. trivolvis IgG reactive with the surface glycocalyx antigen. The IgG level varied over a 40-day period, showing a time-dependent pattern with a peak on day 16 p.i. The results concerning reciprocal cross-reactivity indicate that adult E. trivolvis and E. caproni share at least some of the surface antigens and express species-specific antigenic determinants in ICR mice at similar, nonsignificantly (P = 0.76) different levels.

Animals↗
PubMed1995

Light and scanning electron microscopy of Echinostoma caproni (Trematoda) during maturation in ICR mice.

Light (LM) and scanning electron microscopy (SEM) were used to study the maturation of Echinostoma caproni in 13 ICR mice, each of which was exposed to 50 encysted metacercariae and necropsied at 1-20 weeks postinfection (p.i.). All 13 mice were infected with 20-30 worms/host and half the worms were used for LM and the remainder, for SEM. Body area measurements showed that the worms grew rapidly from day zero (excysted metacercariae) to 4 weeks p.i. and less rapidly thereafter. Area measurements of organs showed that the growth of the acetabular area paralleled that of the body. Gonadal area growth was less rapid than acetabular growth, and the area of the posterior testis was always greater than that of the anterior testis. The most remarkable change in topography occurred by 5 weeks p.i. when some of the ventral tegumentary spines became multipointed with 2-5 points/spine. Spine division was associated with a decline in worm growth, but the significance of this finding is unclear. Spine division probably facilitates the feeding, abrasion, and migration of this echinostome in the mouse small intestine.

Animals↗
PubMed1995

Effects of diet on the lipid composition of the digestive gland-gonad complex of Biomphalaria glabrata (Gastropoda) infected with larval Echinostoma caproni (Trematoda).

This study examined the effects of a larval Echinostoma caproni infection on the neutral lipid composition of the digestive gland-gonad complex (DGG) of Biomphalaria glabrata snails fed hen's egg yolk supplemented with lettuce (Y-L) or lettuce supplemented with Tetramin (L-T). Snails were experimentally infected with the miracidial stage of this echinostome, and their DGGs containing daughter rediae were analyzed for neutral lipids five weeks post-infection by qualitative and quantitative thin-layer chromatography. Light microscopy using Oil Red O (ORO) staining and transmission electron microscopy (TEM) were used to localize neutral lipids in the rediae. The DGGs of infected snails maintained on the Y-L diet showed a significant increase in free sterols and a significant decrease in triacylglycerols compared to uninfected snails maintained on the Y-L diet. The DGGs of infected snails maintained on the L-T diet showed no significant difference in free sterols or triacylglycerols compared to uninfected snails maintained on the L-T diet. ORO staining and TEM showed the presence of lipid droplets in rediae from snails on the Y-L diet. The significant decrease in triacylglycerols in the DGGs of infected snails maintained on the Y-L diet suggests that triacylglycerols were utilized by the rediae.

Animals↗
PubMed1995

The effects of the presence and absence of intestinal contents on survival, size and distribution of Echinostoma caproni in ICR mice.

Fifteen female ICR mice, 6-8 weeks old, were each exposed to 25 metacercarial cysts of Echinostoma caproni. To determine the effects of withholding food on survival, size and distribution of E. caproni in ICR mice, two groups of five each were maintained without food for 1 day (group A) or 2 days (group B) prior to necropsy. Group C consisted of five mice maintained with food for the duration of the experiment. All mice were necropsied at 12 days postinfection. There was no significant difference in worm survival, body area or distribution between group A and C or group B and C mice. The results of this experiment show that short-duration removal of food has no effect on worm survival, size or distribution of E. caproni adults in the small intestine of the ICR mouse.

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