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Biomedical subjects

B Fried

Publications and source records attributed to B Fried.

At least 199 records · Page 11Linked to original sources
PubMed1982

Skin surface lipids of the domestic chicken, and neutral lipid standards as stimuli for the penetration response of Austrobilharzia variglandis cercariae.

Lipids were extracted from the skin of 2-wk-old domestic chickens using sterile cotton gauze dampened with chloroform:methanol (2:1). Preparative thin-layer chromatography separated the skin lipids into six major fractions: phospholipids, free sterols, free fatty acids, triglycerides, methyl esters, sterol esters. The penetration response of the marine avian schistosome cercaria, Austrobilharzia variglandis, to chicken skin lipid fractions, and to neutral lipid standards, was tested by coating lipids on agar in a Petri dish containing a seawater overlay. All neutral lipids tested produced significantly greater penetration responses than the chloroform control. The phospholipid skin fraction killed cercariae. Lipid from whole chicken skin produced the greatest penetration response, followed by free fatty acids and free sterol skin fractions. Of the standards tested, the whole neutral lipid standard, containing cholesterol, oleic acid, triolein, methyl oleate, and cholesteryl oleate, produced the greatest response, followed by the cholesterol standard and the oleic acid standard.

Animals↗
PubMed1981

Localization, length and reproduction in single- and multiple-worm infections of Echinostoma revolutum (Trematoda) in the chick.

Mono-metacercarial infections of Echinostoma revolutum in the domestic chick yielded 14- or 15-day-old worms that produced viable eggs, indicating that this species can self-fertilize under conditions which preclude cross-fertilization. In multiple infection studies, chicks were fed either 5 or 10 cysts and each infected chick contained 2-7 worms at necropsy 14 or 15 days later. Worms from multiple infections were mainly paired or clustered and they tended to locate more posteriorly in the intestine than single worms. Length measurements of single and multiple worms were similar. Both the number of eggs and the percentage of hatched eggs were considerably greater in multiple than in single infections.

Animals↗
PubMed1980

Growth, development and pairing of Leucochloridiomorpha constantiae (Trematoda) metacercariae on the chorio-allantois of chick embryos cultivated in vitro.

A simple in vitro technique was devised to culture chick embryos in Petri dishes from the 4th to the 21st day of incubation. Leucochloridiomorpha constantiae (Trematoda) metacercariae were placed either singly or multiply (5/embryo) on the chorio-allantois of in vitro grown embryos on day 7 and were removed on day 14. Growth and development studies were also made on worms grown singly or multiply (5/chick) in the bursa of Fabricius of the domestic chick. Worms grown singly or multiply in embryos were sexually mature, although eggs from these worms were abnormal when compared with eggs from worms recovered from chicks. The mean body area of worms from chicks was 2-3 times greater than that of worms from embryos. The mean body area of single worms from embryos was significantly larger than that of worms grown multiply in this site. However, the mean body area of multiple worms from the chick was significantly larger than that of single worms from this site. Worm pairs or clusters were seen in all embryos with the multiple infections.

Allantois↗
PubMed1980

In vitro pairing of Echinostoma revolutum (trematoda) metacercariae and adults, and characterization of worm products involved in chemoattraction.

In vitro pairing studies were done on chemically excysted metacercariae and on adults of Echinostoma revolutum maintained in vitro in agar-Locke's petri dish cultures at 39 +/- 1 C for up to 24 hr. Whereas newly excysted metacercariae did not pair, both immature and mature adults showed significant pairing. Adult echinostomes confined in dialysis sacs emitted excretory-secretory (EC) products which significantly attracted single echinostome adults in vitro. Only the lipophilic fraction of ES products was found to elicit attraction. Preparative TLC analysis of adult echinostomes produced three major bands as follows: I (phospholipids); II (free sterols); and III (free fatty acids + triglycerides). When tested in vitro, only the free sterol fraction significantly attracted single adult echinostomes. TLC and GLC analyses of free sterols of E. revolutum have indicated that cholesterol is the major free sterol.

Animals↗
PubMed1980

Concurrent infections of cecal trematodes, Zygocotyle lunata, and Notocotylus sp., in the domestic chick and observations on host-parasite relationships of Notocotylus sp.

Single and concurrent infections of cecal trematodes, Zygocotyle lunata and Notocotylus sp., were studied in controlled, laboratory infections in the domestic chick. The recovery of Notocotylus sp. from the chick cecum was reduced significantly in the presence of Zygocotyle lunata. Neither the size nor the distribution of either helminth was affected by the presence of the other. The ventral surface of Notocotylus sp. was associated intimately with the cecal villus, and this fluke fed on host blood.

Animals↗
PubMed1979

Studies on encystment of Echinostoma revolutum cercariae.

Cercariae of Echinostoma revolutum encysted in the kidney of the snail Physa heterostropha within 1 hr and on mucus trails from Helisoma trivolvis, P. heterostropha and Lymnaea sp. within 2 hr. Significantly, more normal cysts were formed in mucus of Helisoma than in mucus of Physa or Lymnaea. Optimal, in vitro encystment occurred within 24 h in either Locke's 1 : 1 or Locke's 1 : 1 + 1% glucose. Significantly more normal cysts occurred in the Locke's 1 : 1 medium. Both normal and abnormal cysts from Lock's media and snail mucus excysted in an alkaline bile trypsin medium. Cercariae did not encyst in Lock'e media supplemented with casein hydrolysate or in agar cultures containing various chemicals.

Animals↗
PubMed1979

Thin-layer chromatographic analysis of phospholipids in Echinostoma revolutum (Trematoda) adults.

Thin-layer chromatographic analyses were made of phospholipids extracted from adult Echinostoma revolutum (Trematoda) and from the nonnutrient medium in which worms were maintained. Identity of phospholipids was based on comparison with authentic lipid standards and on specific chemical detection tests. The most abundant phospholipids in the extract were phosphatidyl choline, phosphatidyl ethanolamine and phosphatidyl serine; lesser amounts of cerebrosides and lysophosphatidyl choline were detected also. Phospholipids detected in the incubation medium were essentially as described for extracts.

Animals↗
PubMed1978

Host-parasite relationships of Zygocotyle lunata (Trematoda) in the domestic chick.

Domestic chicks were infected with Zygocotyle lunata to determine gross and histopathological effects on the caecal tissues, to observe the method of feeding by worms and to examine the effects of crowding on the growth and development of the worm. Caecal weights and dimensions were significantly reduced in infected chicks. Caecal debris, abundant in control chicks, stained positive for proteins, polysaccharides, acid mucopolysaccharides and neutral fats. Caecal debris was rarely seen in infected chicks. The lumen of the intestinal caeca of the worms contained acellular material which showed protease activity and stained positive for proteins, polysaccharides and acid mucopolysaccharides. Histopathological effects of the infection showed a disruption of the architecture of host caecal mucosa, worm to worm attachment, tissue plugs in the worm acetabulum, and an engorgement of host mucosal tissue with erythrocytes. Stunting due to worm crowding was very evident and by 2 weeks post-infection, worms from single-worm infections were sexually mature and more than twice the length of immature flukes obtained from chicks infected with 100-500 cysts.

Animals↗
PubMed1978

In vivo and in vitro excystation of Zygocotyle lunata (Trematoda) metacercariae and histochemical observations on the cyst.

Encysted metacercariae of Zygocotyle lunata (Trematoda) excyst within 2 hr postexposure in the lower ileum of the domestic chick. Optimal in vitro excystation of this species occurs following pretreatment of the cyst for 15 min in 1% acidified pepsin, treatment in 0.02 M sodium dithionite (a reductant) for 1 to 2 min and then 2 hr treatment in an excystation medium containing 1% sodium glycocholate plus 1% trypsin in Earle's BSS adjusted to pH 8.8 with tris and maintained at 41 C. The cyst of this species is a dome-shaped hemisphere containing an inner and outer wall. The outer wall contains mainly acid mucopolysaccharides, whereas the inner wall is mainly proteinaceous. The cyst contains a ventral lid which only was visualized during excystation.

Animals↗