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Biomedical subjects

R Gothe

Publications and source records attributed to R Gothe.

At least 109 records · Page 6Linked to original sources
PubMed1986

[Arthropods as coproscopic findings in dogs and cats].

A review is given on arthropodes which might occur in faeces of dog and cat in Central Europe in correspondence to their route and way of infestation, including findings based on our own faecal examinations. Tables are given for the diagnosis of preimaginal stages and a key for the identification of imagines. The veterinary importance of such coprological findings as well as possible therapeutic measures are discussed.

Animals↗
PubMed1986

Investigations into the function and chemical compositions of the porose areas secretion of Rhipicephalus evertsi evertsi during oviposition.

Major differences were observed in hexane, ethanol and butanol extracts of eggs obtained from Rhipicephalus evertsi evertsi females in which the porose areas functioned normally (AP+ eggs) and from R. evertsi evertsi in which the porose areas were selectively destroyed by electrocautery (AP- eggs). Mass yields and UV spectra of the hexane extracts were similar for AP+ and AP- eggs. The UV spectra changed only slightly in the 294-320 nm range with respect to time and temperature. High performance liquid chromatography revealed 2 components which originate from the porose areas. Mass spectroscopy of these components indicated the presence of aliphatic and phenolic groups. The ethanol and butanol extracts showed quantitative but no qualitative differences with respect to AP+ and AP- eggs. Electrophoretic fractionation of the butanol extracts revealed the presence of proteins in the secretion of the porose areas. Apart from this information on the chemical composition of the secretion, no indication was obtained of their function during oviposition of R. evertsi evertsi.

Animals↗
PubMed1986

Isolation of a neurotoxin from the salivary glands of female Rhipicephalus evertsi evertsi.

A quantitative study of the changes in the protein pattern of the salivary glands of female Rhipicephalus evertsi evertsi during the entire repletion process was undertaken. These results, in conjunction with the previously determined toxic phase, indicated the presence of a toxic protein. The development of a sensitive in vitro assay using a Xenopus nerve-muscle preparation, made it possible to identify toxic phases during feeding and to assay fractions of salivary gland extracts during toxin isolation. Sufficient amounts of electrophoretically and chromatographically homogeneous toxin could be obtained through the use of chromatofocusing, enabling its characterization with respect to molecular weight (68 kDa; determined by gel permeation chromatography), pI (6.00), and amino acid composition. The toxin was inactivated by pronase digestion as well as by antiserum.

Amino Acids↗
PubMed1986

Studies on the ability of different strains or populations of female Rhipicephalus evertsi evertsi (Acarina:Ixodidae) to produce paralysis in sheep.

Simultaneous infestation of 3-6 month-old Black-head sheep with 15 South African wild strains of Rhipicephalus evertsi evertsi males and females as well as a strain from Rwanda clearly showed that all strains are capable of inducing paralysis. Assessment of the infestation-rate of engorging female ticks during the period that their mass ranged between 15 and 21 mg/kg sheep body mass indicated that toxicity is quantitatively identical and exhibits no intraspecific gradations. The period between the beginning of infestation to the manifestation of the first clinical symptoms is, however, strain dependent: 4 days for ticks from Warmbaths, and at least 5 days for all other strains.

Animals↗
PubMed1986

Investigations into the paralysis-inducing ability of Rhipicephalus evertsi mimeticus and that of hybrids between this subspecies and Rhipicephalus evertsi evertsi.

Studies performed on sheep showed that Rhipicephalus evertsi mimeticus is a paralysis-competent tick species whose toxicity is either the same as, or only slightly less than that of R.e. evertsi. It was also proved that the paresis or paralysis induced by the mimeticus females is characterized by a constant incubation period which is independent of the tick infestation rate and body mass of the host, and consequently of its age. This period is entirely determined by the state of repletion of the ticks and is regulated by the date of mating. It was further proved that a precise relationship exists between an increase of engorgement or salivation activity and the intensity as well as the persistence of clinical symptoms. Thus only female ticks in the mass range of 15-21 mg are toxic. Strain-dependent differences could not be demonstrated. The infestation rates of subspecific hybrid female ticks, and of their descendants, that are necessary to produce the respective symptoms showed no differences in toxicity. When infestations were limited to a small skin area minimum paresis could frequently not be induced, even though the actual number of ticks applied was sufficient to cause lethal paralysis.

Animals↗
PubMed1985

An investigation into the emission sites of the volatile pheromone produced by females of Argas (Persicargas) walkerae.

By leaving open in turn the genital orifice, coxal apertures and anus, the present study has shown that engorged female Argas walkerae release at least 1 volatile pheromone mainly, or maybe exclusively, from the genital aperture. Although this aggregation-inducing pheromone is perceived by all post-larval stages, engorged males of A. walkerae react most strongly. A possible, but only slight, emission through the anus and the coxal aperatures is also indicated. Most probably, this airborne biosubstance is the primary directing and orienting pheromone in the interrelations between members of this tick species.

Anal Canal↗
PubMed1985

Investigation into the participation of male pheromones of Rhipicephalus evertsi evertsi during infestation.

It was shown in this study that Rhipicephalus evertsi evertsi males emit pheromones in the preparasitic as well as in the parasitic phases. Conspecific unengorged male and female images exhibited a high response to water-soluble volatiles collected from unengorged males. A vigorous assembly of unfed female R. evertsi evertsi occurred on filter paper discs which had been in contact with either unfed or 5- and 9-day fed males. Progressively increasing percentages of conspecific unengorged males reacted to organic soluble volatiles obtained from 5- and 9-day fed males as well as to hexane washings of intact males which had fed for 9 days. It is concluded that R. evertsi evertsi males participate not only as pheromone receptive, but also as pheromone emitting, partners in the intraspecific communication of this tick species.

Animals↗