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Biomedical subjects

A Spielman

Publications and source records attributed to A Spielman.

At least 217 records · Page 12Linked to original sources
PubMed1976

Human babesiosis on Nantucket Island: transmission by nymphal Ixodes ticks.

In order to identify potential vectors of human babesiosis (Babesia microli) in southern Massachusetts, I attempted to transmit the infection via nymphal ticks of that species found to be most abundant on reservoir hosts (Peromyscus leucopus) in nature. Mice were collected at frequent intervals throughout a year in a known enzootic focus on Nantucket Island, and ticks were removed by hand. Ticks of only two species were present; larvae and nymphs of Ixodes scapularis were about 10 times as numerous as were those of Dermacentor variabilis. Accordingly, I. scapularis were used in attempts to transmit a strain of Babesia derived from a human infection recently acquired near the study site. Larvae were permitted to feed on an infected hamster and nymphs derived from these larvae were placed on each of 11 non-infected hamsters. All but one hamster became infected. Nymphs reared from larvae that had attached to a non-infected hamster did not transmit babesiosis to other hamsters. These results suggest that I. scapularis serves as a vector of babesios-s on Nantucket hamsters. These results suggest that I. scapularis serves as a vector of babesiosis on Nantucket Island.

Animals↗
PubMed1975

Neutralization of a togavirus by antivector antisera.

An A. aegypti-propagated togavirus (Sindbis) is neutralized by antisera to both whole-body extracts and to salivary fluid of the vector mosquito. Virus propagated in Vero cells is not neutralized by such antisera. Neutralizing activity resides in the immune globulin fraction of sera. Sera from animals injected with adjuvant neutralized neither virus propagated in mosquitoes nor virus obtained from Vero cells. Although neutralizing titers were low, such activity may protect, to some degree, vertebrate hosts normally exposed to vector antigens.

Aedes↗
PubMed1975

Neutralization of Sindbis virus by antisera to antigens of vector mosquitoes.

Sindbis virus harvested from infected cultures of Vero cells and from Aedes aegypti mosquitoes was used in neutralization tests with sera obtained from guinea pigs immunized with ground A. aegypti and from guinea pigs repetitively bitten by mosquitoes. Employing these antisera, more mosquito-propagated virus was neutralized than was virus grown in cultures of Vero cells. The neutralizing activity resided in the immune globulin fraction and may reflect the production of antibody to vector antigens on the viral envelope.

Aedes↗
PubMed1971

Permeability of the ovarian follicle of Aedes aegypti mosquitoes.

The passage of tracers of various molecular weights into resting and vitellogenic ovarian follicles of Aedes aegypti mosquitoes was studied ultrastructurally. The outermost layer of the follicular sheath (the basement lamina) is a coarse mechanical filter. It is freely permeable to particles with molecular weights ranging from 12,000 to 500,000 (i.e. cytochrome c, peroxidase, hemoglobin, catalase, ferritin, immunoglobulin (IgG)-peroxidase, iron dextran and Thorotrast) that have dimensions less than 110 A. Molecules as large as carbon (300-500 A) are totally excluded. Whereas proteins and polysaccharide tracers permeate the basement lamina with apparent ease, certain inert particles (e.g. Thorotrast, Fellows-Testager Div., Fellows Mfg. Co., Inc., Detroit, Mich.) penetrate more slowly. With respect to the tracers tested, resting follicles are as permeable as vitellogenic follicles. The follicle epithelium of resting or vitellogenic follicles is penetrated by narrow intercellular channels. Our observations suggest that these spaces are lined with mucopolysaccharide material. After permeating the basement lamina, exogenous tracers fill these channels, while the bulk of material accumulates in the perioocytic space. Within 3 hr after imbibing blood, the pinocytotic mechanism of the oocyte is greatly augmented. Pinocytosis is not selective with regard to material in the perioocytic space, since double tracer studies show that exogenous compounds are not separated, but are incorporated into the same pinocytotic vesicle. During later stages of vitellogenesis, 36-48 hr after the blood-meal, the pinocytotic mechanism of the oocyte is diminished. Simultaneously, the intercellular channels become occluded by desmosomes, and the vitelline membrane plaques separate the oocyte and follicle epithelium.

Aedes↗