Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Fecundability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources
PubMed2000

Effects of Triatoma virus (TrV) on the fecundity and moulting of Triatoma infestans (Hemiptera: Reduviidae).

Triatoma virus (TrV) is a Picorna-like virus affecting Triatoma infestans (Klug, 1834), the most important transmitter of Trypanosoma cruzi in South America. The subjects of the present, laboratory study were the longevity and oviposition of female Tri. infestans, from stocks with and without viral infection, and the survivorship and developmental time of their progeny through to second-instar nymphs. On average, adult females from an infected stock lived only a third as long as those from the uninfected, and the mean monthly egg outputs of the 'infected' females was only 20% of that of the uninfected females. Even though the virus can be transmitted transovarially and most, if not all, of the progeny of the infected females were themselves infected, there was no evidence for TrV affecting egg hatchability. A much smaller proportion of the progeny of the females from infected stock than of that of the uninfected females successfully moulted to second-instar nymphs (44% v. 80%); the virus appears to inhibit the moulting process. The progeny of the females from the infected stock developed relatively slowly, spending a mean of 6.1 days as first instars (compared with 3.9 days for the progeny of uninfected females). Together, these data indicate that TrV may be a useful agent for the biological control of Tri. infestans.

Animals↗
PubMed1990

Immunological approaches for manipulation of animal growth, body composition and fecundity.

The ability to manipulate certain physiological processes by using the immune system, so as to regulate endocrine secretions and/or actions is clearly possible. The dramatic effects of immunocastration and the ability to increase ovulation rates in sheep are probably the best examples. Other approaches along similar lines have produced equivocal results, the effects of immunization against somatostatin being the most notable case. Although anti-idiotypic antibody approaches to producing hormone mimics have also been shown to be attainable and, indeed, possibly involved in certain auto-immune dysfunctions of the endocrine system, to date no successful applications of this approach have been demonstrated in commercial livestock. The ability to enhance hormone action using antibodies is an extremely promising area. Its prospects probably hinge on the ability to synthesize suitable short peptides which will mimic epitopes on the hormone and so permit the development of active immunization techniques to produce polyclonal antibodies of restricted and enhancing specificity. It seems less likely that administration of hormones pre-complexed to monoclonal antibodies has any potential as a practical approach to manipulating animal productivity. All of these approaches involving active immunization suffer the same limitations: the highly variable response of individual animals and the general inability to regulate the duration of the response; a need to find suitable adjuvants to replace the almost universally used and commercially unacceptable Freund's adjuvant; and the problem of trying to generate what, in most cases, is an auto-immune response. A second group of approaches consists of attempts to use antibodies in their classical role, that is by targeting antigens or cells for destruction by the immune system. These include, for example, antibodies directed against adipose tissue or cytotoxic antibodies to specific hormones aimed at destruction of the hormone-secreting cells. Since these are passive immunization techniques, the antibodies can be assessed carefully in vitro and administered in appropriate doses. However, success in these applications is largely dependent on the inability of damaged tissues to regenerate, since retreatment is generally precluded because of the anti-immunoglobulin response induced in treated animals. Toleragenic forms of such antibodies or the use of appropriate immunosuppressants may ultimately remove this limitation. Perhaps the greatest current limitation to the use of all of these techniques in animal production systems, however, is public resistance to the use of such techniques.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

Consanguinity, fecundity and post-natal mortality in Karnataka, South India.

The degree of consanguinity of the progeny, the number of live-borns and number of living children were determined in 3350 marriages in Bangalore, Karnataka. The coefficient of inbreeding (F) was 0-02308, higher than in comparable, urban populations in other South Indian states. No significant differences were found between the consanguineous and nonconsanguineous groups in numbers of live-born or living children nor was there any consanguinity-related trend with respect to these parameters.

Birth Rate↗
PubMed1997

Increased longevity of kinetin-fed Zaprionus fruitflies is accompanied by their reduced fecundity and enhanced catalase activity.

Kinetin, a cytokinin plant growth hormone, retards senescence in plants, delays aging in human cells in culture, slows down development of insects and prolongs their lifespan. We have now observed that the increased longevity of Kn-fed Zaprionus fruitflies was accompanied by an increase in the specific activity of catalase during developmental stages and in adult insects. In addition, the egg laying capacity of Kn-fed fruitflies was reduced drastically as compared with those kept on a normal diet. These results support the view that improved maintenance of the soma and prolongation of its life is achieved at the cost of decreased reproductive activity.

Aging↗
PubMed1984

Effect of ingested sperm on fecundity in the rat.

The intragastric administration of homologous strain epididymal sperm to adult virgin NZBW (Rt 1) female rats was shown to induce short-to long-term infertility. Infertility was associated with an early rise of genital secretory fluid IgA antisperm antibody preceding mating.

Administration, Oral↗
PubMed2004

Vaccination of dogs with a recombinant cysteine protease from the intestine of canine hookworms diminishes the fecundity and growth of worms.

We expressed a catalytically active cysteine protease, Ac-CP-2, from the blood-feeding stage of the canine hookworm Ancylostoma caninum and vaccinated dogs with the purified protease. Dogs acquired high-titer, antigen-specific antibody responses, and adult hookworms recovered from the intestines of vaccinated dogs were significantly smaller than hookworms from control dogs. There was also a marked decrease in fecal egg counts and the number of female hookworms in vaccinated dogs. Ac-CP-2 is expressed by the parasite in the brush-border membrane of its alimentary canal, and anti-Ac-CP-2 antibodies were bound to the gut of hookworms from vaccinated dogs, which suggests that these antibodies were ingested by the parasites with their blood meal. IgG from vaccinated dogs decreased proteolytic activity against a peptide substrate by 73%, which implies that neutralizing antibodies were induced by vaccination. These results indicate that cysteine proteases involved in parasite nutrition are promising candidates as vaccines against hookworm disease.

Adjuvants, Immunologic↗