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Biomedical subjects

D L Lee

Publications and source records attributed to D L Lee.

At least 91 records · Page 5Linked to original sources
PubMed1980

Observations on the structure of the male reproductive system and spermatogenesis of Nematodirus battus.

In the male reproductive system of Nematodirus battus the spermatogonia and spermatocytes and arranged upon a central rachis and the spermatocytes are characterized by the presence of cup-shaped membranous organelles which are formed in association with Golgi complexes and granular endoplasmic reticulum. Spermatozoa of N. battus in the male nematode have a electron-dense, conical tail-like region which contains the nuclear material and an elongate cytoplasmic region which contains the cell organelles. In the uterus of the female, however, the cytoplasmic region of the spermatozoon has an amoeboid appearance and in the seminal receptacle the cytoplasmic region is dome-shaped and many of the membranous organelles have connexions with the outer membrane of the spermatozoa. Movement was not observed in spermatozoa released from the seminal vesicle of the male worm.

Animals↗
PubMed1980

Changes in the structure of the male reproductive system of Nematodirus battus during its rejection from lambs.

As the infection progresses in lambs, the developing germ cells of male Nematodirus battus become filled with lysosome-like bodies, electron-dense granules and membrane-bound vesicles, and the organization and division of the gametic nucleus appears to be altered. The epithelial cells of the reproductive tract are also damaged and the secretory-type globules produced by the cells of the vas deferens are denatured. These changes are compared with ultrastructural changes observed in other species of nematode affected by the immune response of their hosts.

Animals↗
PubMed1980

Circulating growth hormone and prolactin concentrations in turkeys and chickens infected with Histomonas meleagridis.

1. Histomonas meleagridis was inoculated into young chickens and turkeys and the effect of the infection (blackhead) on circulating growth hormone (GH) and prolactin concentrations determined. 2. During the course of the infection in turkeys there was a marked increase in plasma GH concentration which correlated with the severity of the disease, as judged by liver and caecal characteristics. The infection was less severe in chickens and no correlation between plasma GH and the degree of infection was observed. 3. The concentration of plasma prolactin was increased in the chicken, but not in the turkey, during the invasive period of infection.

Animals↗
PubMed1978

Changes in the adenylate energy charge of Nippostrongylus brasiliensis and Nematodirus battus during the development of immunity to these nematodes in their host.

Infection of rats with 2000 infective juveniles of Nippostrongylus brasiliensis and of lambs with 60 000 infective juveniles of Nematodirus battus results in a well-marked immunity to these nematodes in their respective host. There is a fall in the adenylate energy charge value of these nematodes during the course of these infections, reaching values of 0.37 in males and 0.27 in females of N. brasiliensis, and 0.31 in males and 0.23 in females of N. battus towards the end of the infections. In hosts given relatively small numbers of infective juveniles, the values for the nematodes removed from the hosts late in the infection remain at a relatively high level. These results indicate that the immune response of the host may affect the energy status of these nematodes, and this could help to explain their subsequent expulsion from the immune host.

Adenine Nucleotides↗
PubMed1977

Interactions in vitro between sporozoites of Eimeria tenella and host peritoneal exudate cells: electron microscopal observations.

The interactions of sporozoites of Eimeria tenella with peritoneal cells from normal and from immunized chickens were examined in vitro. Although the uptake of sporozoites by cells from immunized birds was greater than by cells from susceptible birds, no differences were apparent in their appearance in electron micrographs. Entry into both macrophages and heterophils (comparable to mammalian neutrophils) was by phagocytosis. The findings are discussed.

Animals↗
PubMed1977

Quantitative relationships between steroid structure and binding to putative progesterone receptors.

Relationships between chemical structure of androst-4-en-3-one derivatives and their affinity for putative progesterone receptors are described. The binding affinity for 55 derivatives can be expressed by the equation log relative binding affinity (rabbit receptor) = 1.79 + 0.18 (+/-0.11) pia + 1.45 (+/-0.21) pib + 0.010 (+/-0.002) (surface area in hydrophobic pockets) - 0.012 (+/-0.003) (surface area out of hydrophobic pockets) - 0.99 (+/-0.21) MK - 0.33 (+/-0.08) (conformational changes). For this equation, r=0.88. The equation successfully predicts the affinities of other compounds in the literature. The importance of the surface area terms is discussed.

Androstenes↗
PubMed1976

Qualitative and quantitative histochemical changes in the caecum and liver of turkeys infected with Histomonas meleagridis.

Changes in the amount and distribution of acid and alkaline phosphatase, non-specific esterase, glycogen, lipid and acid mucopolysaccharide in the caecal wall and liver of turkey poults infected with Histomonas meleagridis have been studied histochemically. A microdensitometer was used to measure changes in activity and distribution of acid phosphatase and non-specific esterase in the caecal mucosa. During the course of the infection there is a marked reduction in activity and distribution of acid phosphatase and non-specific esterase but little change in the amounts and distribution of alkaline phosphatase, glycogen, lipid and acid mucopolysaccharide in the wall of the main part of the caecum. Similar, but smaller, changes occurred in the wall of the neck region of the caecum. In the liver most changes occurred in the immediate vicinity of the parasites. Initially, there was a reduction in the amount of glycogen in the parasitic lesions but later in the infection there was a marked loss of glycogen in all regions of the liver. Changes in the caecum are apparently brought about by the parasite prior to and after invasion of the caecal tissues; changes in the liver occur after it has been invaded.

Acid Phosphatase↗
PubMed1976

Observations on crystals found in the intestine of Nematodirus battus during the development of immunity to this nematode in lambs.

Lambs which were given 60000 infective larvae of Nematodirus battus progressively threw off adult nematodes from day 20 onwards. Large, hexagonal crystals appeared in the intestine of the adult nematode at about this time and caused blockage of the intestinal-rectal or -cloacal junction. Lambs which were given 1000-2000 infective larvae did not throw off the infection, and adult nematodes from lambs which had been infected for up to 74 days did not contain these crystals. Chemical, histochemical and x-ray microanalysis tests on the crystals indicated that they are lipoprotein in composition. The crystals arise within the lumen of the nematode and appear to be associated with the development of immunity to this nematode in lambs.

Animals↗