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P F Basch

Publications and source records attributed to P F Basch.

At least 37 records · Page 2Linked to original sources
PubMed1986

Schistosomiasis in China: an update.

A study tour in China provided information on the current status of schistosomiasis. Although many counties have been cleared of Oncomelania snails, problem areas still exist in the lakes region of the central Yangtze Valley, in hilly or mountainous terrain, and where water level cannot be controlled. In the central Yangtze area the main reservoir of infection is now considered to be cattle. It was estimated that the prevalence of schistosomiasis in 1983 was about 2.4 million cases, mostly light. Considerable effort is being made to develop immunodiagnostic methods to identify the relatively few and often subclinical cases that occur in sparsely endemic areas. Nationwide eradication does not seem feasible at present, necessitating continued surveillance to maintain and consolidate progress and prevent reintroduction of the parasite or its host snails in areas freed from the disease.

China↗
PubMed1986

An alginate matrix double-embedding method for paraffin sectioning of minute specimens.

A method has been devised for placing minute specimens in viscous aqueous sodium alginate solution, which is polymerized in 0.25 molar calcium chloride. The resulting matrix can then be dehydrated, embedded, and sectioned, maintaining the orientation of the specimens. The sectioned alginate can be dissolved in 0.1 molar EDTA if desired. Tissue sections respond to normal staining procedures.

Alginates↗
PubMed1985

Wound healing in the trematode Schistosoma.

The ability of adult Schistosoma mansoni to effect wound healing over an exposed surface has been demonstrated. In transected worm segments a new external plasma membrane formed over the exposed tegumental cytoplasm. An elevated leading edge of tegument developed around the margin of the wound; the surface of this region was highly convoluted and there was a proliferation of membranous bodies within its cytoplasm. Inward migration of the leading edge over the exposed internal tissues took place. The resulting new tegument lacked spines and sensory endings. There was no regeneration of basal lamina or tegumentary cytons. In vitro maintenance of worm segments for 3 weeks did not give rise to any major ultrastructural changes in the tissues away from the wound.

Animals↗
PubMed1984

Reproductive development of female Schistosoma mansoni (Digenea: Schistosomatidae) following bisexual pairing of worms and worm segments.

Maturation and maintenance of normal reproductive function in female Schistosoma mansoni require a permanent association with the male, but the nature of this relationship is not well understood. The regional localization of a stimulatory factor in the male and its target in the female were investigated. Unisexual female and mature male worms were transected into segments of various lengths. Various combinations of transected male and female segments and intact worms were transferred to the mesenteric veins of recipient hamsters and were also maintained in vitro. In hamsters and in vitro, pairing took place between intact worms of each sex and segments of the other, and between segments of both sexes. The majority of female worms and segments so paired showed some reproductive development, as assessed by vitelline gland differentiation. In intact unisexual females paired with small male segments, vitelline gland development was limited to that portion of the worm that had been held by the male. Worm segments continued to display normal body contractions throughout 24 days of in vitro maintenance and morphological integrity was retained. It is concluded that 1) in the absence of a functioning gut, worm segments can survive for prolonged periods on nutrients absorbed through the tegument; 2) worm pairing, male stimulation, and the female developmental response are independent of central nervous control by the cerebral ganglia; 3) males have no centralized localization for the female-stimulating factor; 4) vitelline gland differentiation in the female requires local stimulation through male contact, and this is not propagated throughout the worm.

Animals↗
PubMed1984

Putative polypeptide transfer from male to female Schistosoma mansoni.

Mature males and females, and unisexual females of Schistosoma mansoni were incubated in medium containing [14C]leucine. By use of polyacrylamide gel electrophoresis and fluorography no differences were detected in their ability to synthesize polypeptides. Male worms thus labelled were paired for various periods with unlabelled mature or unisexual females both in vitro and by surgical implantation into hamsters. Female worms paired in vitro had two controls: an accompanying female that did not pair and an additional female placed in the conditioned medium after removal of the other worms. After separation and washing, only small amounts of label were found in females by liquid scintillation counting despite the release by males of substantial amounts of label into the medium. No label was detected in fluorograms of polyacrylamide electrophoresis gels of re-paired females after 7 days' exposure to X-ray film, but a faint pattern of normal polypeptides above 50 kDa did develop after 6 weeks. In light microscope autoradiographs a low grain count was found over sections of unlabelled females paired with labelled males but this was no greater than that over females incubated in medium that had formerly held males. We have been unable to detect any polypeptide reported to be synthesized exclusively by male worms and transferred in large amounts to females. Although female worms did take up small amounts of male-derived metabolic products, the transfer of a specific polypeptide of 66 kDa in significant quantities did not take place under the conditions investigated.

Animals↗
PubMed1984

Intergeneric reproductive stimulation and parthenogenesis in Schistosoma mansoni.

When mice were infected with female cercariae of Schistosoma mansoni and male cercariae of Schistosomatium douthitti, many mixed pairs formed. The paired females were approximately the same size as those in unisexual infections, far smaller than females paired with S. mansoni males. Although the Sch. douthitti males possessed well-developed testes, sperm were not found in their female partners, which developed scanty vitelline glands and produced laterally spined eggs typical of S. mansoni. Such eggs yielded swimming miracidia infective to the snail host of S. mansoni, Biomphalaria glabrata, but not to the lymnaeid snail host of Sch. douthitti. Sporocysts arising from these miracidia were haploid and produced cercariae infective to mice. Parthenogenetically derived female cercariae in mice co-infected with either parthenogenetically derived male or normal diploid male S. mansoni developed to large adults of normal appearance, whose eggs yielded diploid miracidia and subsequent generations of normal diploid schistosomes. Parthenogenetically derived females co-infected with Sch. douthitti males also paired and produced some eggs containing viable miracidia, which gave rise once again to haploid sporocysts. These observations confirm previous suggestions that the stimulus for maturation in female S. mansoni is distinct from that for growth, and is independent of insemination and fertilization. It is concluded that both diploid and haploid S. mansoni females are capable either of parthenogenesis or of bisexual reproduction when appropriately stimulated.

Animals↗
PubMed1984

Development and behavior of cultured Schistosoma mansoni fed on human erythrocyte ghosts.

Schistosomula and adults of Schistosoma mansoni were grown from cercariae in cultures differing only in the treatment of the red blood cells fed to the organisms. "Pink ghosts," containing about 5% of the original hemoglobin, were produced by hemolysis in water; "white ghosts" with no detectable hemoglobin were made in 5 mM phosphate buffer, pH 8. Early growth and development were more rapid and vigorous, and pairs formed more readily when pink ghosts, rather than intact erythrocytes were fed. Schistosomula remained stunted and undeveloped when fed with white ghosts. Attempts at reconstitution of the latter by addition of hemoglobin, concentrated erythrocyte lysate, or pressure-liquefied pink ghosts did not restore growth-promoting activity. Pink ghost-fed worms, particularly paired males, attached to the dish bottom by their acetabulum and oral sucker and travelled by an active looping motion. Substrates of collagen or fibrin or a mammalian cell monolayer did not affect this behavior. Such attachment and locomotion are interpreted as instinctive migratory behavior of schistosomes.

Erythrocyte Membrane↗
PubMed1983

Reproductive ultrastructure of adult Schistosoma mansoni grown in vitro.

The reproductive organs of paired S. mansoni adults cultured from cercariae were examined by transmission electron microscopy to assess their development. In males, many mature sperm, closely associated with the sustentacular cells, were produced in the testes. In females, although the vitelline gland had fewer lobules than were found in worms from animal infections, the cytoplasm of many vitelline cells contained abundant vitelline and lipid droplets. The structure of the Mehlis' gland, ootype, and uterus resembled that of in vivo adult females. However, in the ovary, the oocytes tended to degenerate, and within the ootype and uterus the oocytes were not embedded within egglike material. We conclude that a dysfunction of ovarian development is the primary reason for the reproductive failure of schistosome pairs grown in vitro under our experimental conditions.

Animals↗
PubMed1983

Schistosoma mansoni: reproductive potential of male and female worms cultured in vitro.

We studied the development of S. mansoni after various combinations of ex-vivo, cultured, and unisexual male and female worms were implanted into hamsters. Females of any type, co-implanted with ex-vivo males, were capable of developing to maturity and producing eggs containing viable miracidia. Cultured males often did not induce adequate growth and maturation of females, but viable miracidia were produced in some animals co-implanted with cultured males plus cultured, ex-vivo, or unisexual females. We concluded that both cultured males and females have the potential for full growth and reproductive maturation, but are retarded in vitro by inadequate culture conditions.

Animals↗
PubMed1982

Acidic thiol proteinase activity of Schistosoma mansoni cultured in vitro.

Schistosoma mansoni cultured in vitro for periods from 12 days to 33 weeks were analyzed for proteinase activity using a fluorescent substrate and compared with adult S. mansoni worms from infected mice. The enzyme activity measured was that of an acidic thiol-dependent proteinase previously described. Proteinase activity appears early in development, and rises rapidly to an approximately constant proportion of the total extractable worm protein. Cultured worms have 5 to 20 times higher specific activity than in vivo-developed worms. However, cultured worms and in vivo worms have approximately equivalent activities per worm.

Animals↗
PubMed1982

Schistosoma mansoni: scanning electron microscopy of schistosomula, adults and eggs grown in vitro.

Development of surface topography of cultured Schistosoma mansoni was followed in the cercariae, newly transformed and older schistosomula, and adults. Comparison with surface features of schistosomes from animal infections revealed no apparent differences in tegumental folding or morphogenesis, spines, sensory structures, or other components. Eggs produced by worm pairs grown in vitro were grossly abnormal, usually composed of loosely packed vitelline granules and lacking a shell.

Animals↗
PubMed1981

Cultivation of Schistosoma mansoni in vitro. I. Establishment of cultures from cercariae and development until pairing.

Procedures are described for mass cultivation of Schistosoma mansoni. Cercariae were pooled, concentrated, and axenized through a series of washes in base medium containing antibiotics. Cercariae were sheared through a double-Luer-ended needle connected to two syringes, and tails separated and discarded. Young schistosomules were grown in a medium based upon BME augmented with lactalbumin hydrolysate, glucose, hormones, and other amendments and supplemented with human serum. Human blood cells (Type O) were added to cultures. Intestinal pigment was seen on the 5th day and gut cecal fusion began on day 11. Schistosomules developed steadily to pairing, which was seen first during the 7th wk of culture. Pairing occurred somewhat later in relation to development in vivo.

Animals↗
PubMed1981

Cultivation of Schistosoma mansoni in vitro. II. production of infertile eggs by worm pairs cultured from cercariae.

Schistosoma mansoni grown from the cercarial stage in vitro produced infertile eggs in about 10% of the pairs studied. Cultured eggs were about half normal size, had a small and blunt lateral spine, and appeared to lack a germinal disc. The shell opposite the spine was typically thin and poorly formed. Eggs were often found in dyads. Vitelline conglomerates in long strands were sometimes deposited. Vitelline glands, ovaries, and testes were relatively poorly developed. Alterations of gas phase or addition of reducing agents, antioxidants, steroid hormones, specific adsorbents, or adult worm extracts did not improve the worms or augment egg production.

Animals↗
PubMed1981

Cultivation of Schistosoma mansoni in vitro. III. implantation of cultured worms into mouse mesenteric veins.

By injection into mice we assessed the potential for full development and oviposition of young schistosomules, juveniles, and paired adults of Schistosoma mansoni, all grown in vitro from cercariae. Schistosomules 2-hr or 13-days-old were injected into mice via the tail vein; older worms were implanted surgically into the ileocolic vein. Also implanted were previously ovigerous adult pairs that had been perfused from mice and maintained in culture up to 53 days. Eventually, all were capable of producing viable eggs except the worm-pairs that had been grown to the adult stage in vitro; these failed to grow or develop further when implanted into mice. We concluded that pairs once mature in vivo could regain the capacity for oviposition even after prolonged maintenance in vitro, but worms grown entirely in vitro to pairing may have missed some required stimulus which cannot be furnished later, even by an adequate animal host.

Animals↗
PubMed1979

Bge snail cell-line antigens: ineffectiveness as antischistosomal vaccine in mice.

Mice and rabbits were immunized with antigens derived from Bge cells, Biomphalaria glabrata hemolymph, or Schistosoma mansoni. Antisera from mice given molluscan antigens did not form immunoprecipitates with soluble antigen from adult worms, but their binding to surfaces of sporocysts, cercariae, and schistosomules suggests the presence of cross-reacting determinants. In vitro, cell-mediated immune responses to Bge antigens were not demonstrable in infected nor in immunized mice. Mice immunized with Bge cell-line antigens and challenged with S. mansoni cercariae showed no reduction in worm burden when compared with control mice.

Animals↗
PubMed1977

Metacercarial cyst formation in vitro of Echinostoma paraensei.

Cercariae of Echinostoma paraensei Lie and Basch 1968 encysted normally in the presence of Biomphalaria glabrata embryo (Bge) cells in culture, partially in culture conditioned medium, and not at all in fresh culture medium alone. At the ultrastructural level the cyst is composed of 2 well defined regions. The outer cyst wall (OCW) is particulate to fibrous in nature, formed from secretory granules released from the cercarial tegument. Membranous scrolls or rodlets secreted from the subtegumental cystogenous gland cells are then added to this layer, forming the inner cyst wall (ICW). After 24 hr the cultured cyst is enclosed by a thin cellular capsule similar to that found around cysts in the snail host. The capsule also contains collagen fibers, not found elsewhere in Bge cell cultures.

Animals↗
PubMed1977

In vitro development of Schistosoma mansoni cercariae.

Early cercarial embryos of Schistosoma mansoni developed to swimming cercariae within seven days in vitro, via the same sequence of stages as reported in vivo. The presence of living Biomphalaria glabrata cells (Bge line) was indispensable for proper development. Cultured cercariae were water-sensitive, gave no cercarienhüllen reaction, and appeared to lack the surface glycocalyx. Further development was not detected in mice or hamsters.

Animals↗