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Biomedical subjects

R C Jones

Publications and source records attributed to R C Jones.

At least 181 records · Page 10Linked to original sources
PubMed1984

Subcutaneous and intrabursal administration of an LRH agonist to the pregnant hemicastrated rat during preimplantation.

A single injection of the LRH agonist, Wy-40,972, under the right ovarian bursa (IB) on any individual day (D) 1-7 in the pregnant rat increased still further the compensatory ovarian weight gain produced by hemicastration (HC) alone. Conversely, a single subcutaneous (sc) injection during the same period abolished the compensatory hypertrophy and reduced the weight of the remaining ovary to that of the ovary of the intact rat and below. The single sc or IB injections of Wy-40,972 were most effective in delaying implantation when administered on D3-4 or 4, respectively. Subcutaneous administration on D5, 6, or 7 produced an antifertility effect, whereas IB administration on any of these 3 days failed to modify the pregnancy. These data demonstrate that the LRH agonist, Wy-40,972, acts directly on the ovary with regard to both weight increase and delay of blastocyst implantation. The results are discussed in relation to hormonal requirements for implantation and desensitization of the ovary.

Animals↗
PubMed1984

Serological response and virus shedding of chickens inoculated with reovirus via different routes.

A comparison of the serological responses to a reovirus administered by the eye-drop, intramuscular, oral and subcutaneous routes was made in three-week-old chickens. Their patterns of virus shedding were also compared. All four routes resulted in an antibody response and no virus excretion in faeces more than two to three weeks after administration. The oral route represented the most favourable route for live reovirus vaccine administration.

Administration, Oral↗
PubMed1983

Blastocyst attachment in the ovariectomized rat treated with an intrauterine injection of luteinizing hormone-releasing hormone (LRH).

Pregnant rats were bilaterally ovariectomized on day 3 and the blastocysts were maintained in a state of delayed implantation by the daily sc injection of 4 mg progesterone from day 3 to 6. On the morning of day 6 the rats received an intrauterine injection of 1 mg LRH in the right horn. A second group of rats was treated as above and was additionally injected with 2 mg of indomethacin on day 5 and 1 mg on the morning of day 6. Fifteen min prior to autopsy the animals were injected iv with a 0.5% solution of Evans Blue. The presence of uterine blue bands and the number of blastocysts recovered from the right and left (control) horns were recorded at 0.25, 0.5, 1.2 and 4 h after the injection of LRH. It was determined that the number of blastocysts flushed from the treated horn was significantly reduced below that of the control left horn within 15 min and at every autopsy interval thereafter. In addition, blue bands appeared in the treated horn as early as 15 min after the injection of LRH demonstrating that implantation had occurred in a few instances. No blue bands appeared in the control horns. The injection of indomethacin did not inhibit the attachment or implantation of blastocysts or the presence of blue bands in the treated horn. A possible role for blastocyst oestrogen is discussed.

Animals↗
PubMed1983

Sperm maturation, fluid transport, and secretion and absorption of protein in the epididymis of the echidna, Tachyglossus aculeatus.

Extratesticular sperm maturation in the echidna mainly occurs in the initial segment of the ductus epididymidis. The process involves the development of motility, migration and loss of the cytoplasmic droplet, a decrease in permeability to Congo red and the formation of sperm bundles. The spermatozoa are supported in the bundles by a matrix of electron-dense material; the bundles are very motile is undiluted samples of luminal fluids. Micropuncture studies of anaesthetized echidnas showed that the ductuli efferentes absorb 74% of the fluid and 46% of the soluble protein that enters them. The initial segment of the ductus epididymidis absorbs 83% of the fluid which enters it, and its secretions increase the concentration of protein in luminal fluid by 107%. Denatured, linear-gradient polyacrylamide gel electrophoresis of micropuncture samples showed that 1 protein (apparent M4 = 100 500) which is not present in blood plasma is present in rete testis fluid, and a glycoprotein which is present in rete testis fluid (apparent Mr = 78500) is absorbed by the ductuli efferentes. Six proteins which are not present in blood plasma are secreted into the initial segment of the ductus epididymidis; 5 are glycoproteins (apparent Mr = 48500, 39000, 32000, 20500 and 19000) and one (apparent Mr = 82500) is not. The most prominent electrophoresis bands corresponded to the glycoproteins with apparent molecular weights of 48500, 20500 and 19000.

Animals↗
PubMed1982

Production, transport, maturation, storage and survival of spermatozoa in the male Japanese quail, Coturnix coturnix.

Male Japanese quail have relatively large testes (2.26% of body weight), a rapid rate of spermatogenesis (14.4-15.8 days) and an efficient production of spermatozoa (92.5 x 10(6)/g testis per day). The daily output of spermatozoa is high (308 x 10(6) per bird, 2.08 x 10(6) per g body weight). The total number of extragonadal spermatozoa was 308 x 22 x 10(6) per bird. Spermatozoa were transported through the genital ducts in about 1 day, maturing quickly in the epididymal region and stored briefly in the ductus deferens. Spermatozoa isolated in the ductus deferens by ligatures around the duct rapidly lost the capacity for motility after 3 days. It is concluded that, compared to mammals such as the rat, the reproductive strategy of the quail involves the rapid production, maturation and transport of spermatozoa through the reproductive tract, in association with a limited capacity to store spermatozoa for long periods within the male genital ducts.

Animals↗
PubMed1982

Ultrastructure of the ductus epididymidis of the echidna, Tachyglossus aculeatus.

It is concluded that the ductus epididymidis of the echidna is divided into only two structurally distinct segments which are each homogeneous along their length. The initial segment in the echidna is structurally very similar to the initial segment proper in the epididymis of all other mammals which have been studied, whereas the terminal segment is structurally quite different from the terminal segment in other mammals. The terminal segment in the echidna is involved in considerable apocrine secretion of highly membranous material. The secretions gradually degenerate and occupy a large proportion of the lumen of the duct.

Animals↗
PubMed1981

Histoplasmosis of bone.

A case of histoplasmosis of bone manifested by a single punched-out lesion in the humerus is reported in a man with asymptomatic mild chronic disseminated histoplasmosis. Roentgenologically evident lesions of bone due to Histoplasma capsulatum are rare, and this is the only report of a large punched-out lytic lesion. Such lesions are common in disseminated histoplasmosis due to the African strain H. duboisii. Although H. duboisii has been accorded species differentiation, there are only two clearly defined differences, compared to H. capsulatum. One is morphologic (size of yeast cell), and the other is a different clinical disease spectrum. Many believe that this organism is best viewed as a stable variant of H. capsulatum. At times, the two strains are indistinguishable morphologically, and at times, as in the case reported, there may be clinical similarities in their respective disease entities.

Aged↗
PubMed1981

Isolation of viruses from outbreaks of suspected tenosynovitis (viral arthritis) in chickens.

Specimens from the legs of chickens from 84 outbreaks of suspected tenosynovitis were examined for the presence of viruses by culture in chick embryo lung or liver cell monolayers. All samples were from broilers or broiler breeders, ranging in age from dead-in-shell embryos to 36 weeks old. Twenty-five outbreaks (29.8 per cent) yielded viruses of which 12 were reoviruses alone, 12 adenoviruses alone, and one, a mixture of both types of virus. Rupture of the gastrocnemius tendon was seen in 12 outbreaks and viruses were isolated from six of these: three were reoviruses and three were adenoviruses. Approximately half the affected flocks from which specimens were received were in the six to 14 week age range. With one exception, all the reovirus isolations were made from chickens of 11 weeks or under, while adenovirus isolations showed more scatter with regard to age.

Adenoviridae↗
PubMed1981

Studies of the deferent ducts from the testis of the African elephant, Loxodonta africana. III. Ultrastructure and cytochemistry of the ductuli efferentes.

The epithelium of the ductuli efferentes is composed of ciliated, principal, halo and basal cells. The supranuclear cytoplasm of ciliated cells is penetrated by particularly long cilial rootlets which are surrounded by numerous elongate mitochondria. Microtubules are arranged along the longitudinal axis of the cells. The spaces between the microvilli of principal cells form canaliculi which penetrate the apical cytoplasm and appear to be involved in endocytotic activity. The supranuclear cytoplasm contains oval mitochondria and numerous vacuoles. Both ciliated and principal cells contain poorly developed Golgi and endoplasmic reticulum, but numerous supranuclear dense bodies are usually present. Supranuclear and basal accumulations of dense bodies were identified as lipofuscin; they were the source of brown pigmentation in the proximal two thirds of the ductuli efferentes. The halo cells were probably macrophages. They occurred quite frequently and contained crescent shaped nuclei and large accumulations of lipofuscin material.

Animals↗
PubMed1981

Structural differentiation of the male genital ducts of the echidna (Tachyglossus aculeatus).

Seven ductuli efferentes radiate from the testis of the echidna and join the ductus epididymidis either directly or after joining one of their neighbours. They are pigmented brown and appear to be structurally and functionally similar to the ductuli efferentes of therian mammals. The epididymis is anatomically differentiated into a large head and small tail which appear to be, respectively, larger and smaller than the similar regions of the epididymis of scrotal mammals; they also contain, respectively, larger and smaller proportions of the animals' extragonadal spermatozoa. Only the head of the epididymis is adjacent to the testis: the tail and the ductus deferens are distal to the testis. The ductus epididymis is also histologically differentiated into two segments (initial and terminal segments) which correspond precisely with the anatomical differentiation. The initial segment is structurally similar to the initial segment of the epididymis of scrotal mammals (i.e. tall epithelium with long stereocilia, a farily homogeneous supranuclear cytoplasma containing Golgi apparatus and a low concentration of spermatozoa in the lumen). The terminal segment has adaptations of the duct (as in scrotal mammals) for the storage of spermatozoa such as a wide lumen containing a high concentration of spermatozoa, low epithelium and thick layers of periductal muscle. However, it is peculiar in that the duct epithelium is thrown into folds and it is involved in considerable apocrine secretion.

Animals↗
PubMed1980

Local antifertility effect of luteinizing hormone-releasing hormone (LRH) in the rat: mechanism of action.

The administration of luteinizing hormone-releasing hormone (LRH) into one horn of the uterus at 0900 h on D5 of pregnancy produces a 96% reduction in the number of zona-encased blastocysts recovered between 0915 and 1300 h on D5. The number of blastocysts recovered within this time period also decreased; only one blastocyst was recovered from the LRH-treated horn at 1300 h while 26 were flushed from the horns injected with saline. The results of this study suggest that LRH causes a premature disassociation of the zona from the blasocyst allowing early adherence to the uterine wall. This asynchronous attachment results in disruption of the ensuing pregnancy.

Animals↗
PubMed1980

Luminal composition and maturation of spermatozoa in the genital ducts of the African elephant (Loxodonta africana).

The mean spermatocrit and sodium, potassium and protein concentrations of fluid collected from the rete testis of the elephant were similar to values described for the ram. Sperm maturation, as assessed by the location of the cytoplasmic droplet in the middle pice, occurred in the distal head and the isthmus of the epididymis (middle segment). Spermatocrit determinations indicated that 96% of the fluid leaving the testis was reabsorbed by the efferent ducts and proximal initial segment, and 53% of the remainder was reabsorbed in the more distal parts of the head of the epididymis (initial and proximal middle segments). Sodium was reabsorbed in the same concentration as luminal fluid and not in amounts equimolar with potassium. The potassium concentration increased from 12.1 mequiv./l in rete testis plasma to 64.8 mequiv./l in the proximal head of the epididymis. About two thirds of the protein in rete testis fluid (3.8 mg/ml) was reabsorbed by the efferent ducts and more was absorbed by the head of the epididymis.

Animals↗
PubMed1980

Studies of the deferent ducts from the testis of the African elephant, Loxodonta africana. II. Histochemistry of the epididymis.

The three main segments of the elephant epididymis were examined for the occurrence, in the spermatozoa and lining epithelium, of carbohydrates, neutral lipids and phospholipids, ATPase, alkaline phosphatase, succinic dehydrogenase, glucose-6-phosphate dehydrogenase, diaphorases, hydroxysteroid dehydrogenases, acid phosphatase and non-specific esterase. The most distinct feature of the carbohydrate content of the epididymis was a layer of acidic, alcian blue-positive glycoprotein over the luminal surface of the epithelium, particularly in the terminal segment. PAS-positive, diastase-resistant inclusions were also found throughout the epdidymis. Neutral lipid occurred as droplets above and below the nucleus in the epithelium of the middle segment, and as supranuclear accumulations in the terminal segment. All the enzymes except the steroid dehydrogenases were detected in the epididymal epithelium, and all except the steroid dehydrogenases and acid phosphatase were detected in the spermatozoa. There was considerable variation in the intensity of the cytochemical reactions in the epithelium, but not in the spermatozoa, in different regions of the epididymis. In general, the enzymes involved in active transport showed strongest reactions in the initial and terminal segments, the reactions in the stereocilia being the most intense. The enzymes involved in energy metabolism showed strongest reactions in the middle and terminal segments, with the activity being fairly evenly distributed throughout the cytoplasm of the principal cells. However, the two lysosomal enzymes which were studied showed quite different distributions: the reactions for acid phosphatase were strongest in the initial and middle segments, whilst the reactions for non-specific esterase were strongest in the middle and terminal segments. It is suggested that the initial segment is involved in absorptive and anabolic activity, the middle segment in anabolic activity, and the terminal segment (where spermatozoa are stored ready for ejaculation) in considerable metabolic activity and active transport of substrates across the epithelium.

Acid Phosphatase↗