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Biomedical subjects

J K Miller

Publications and source records attributed to J K Miller.

At least 91 records · Page 5Linked to original sources
PubMed1982

Clinical and serological response of pregnant gimmers to experimentally induced toxoplasmosis.

Thirty-five Scottish blackface gimmers in mid or late pregnancy were infected with Toxoplasma gondii by subcutaneous injection of 2000 tissue cysts. Approximately half the gimmers developed a mild febrile response between eight and 10 days after infection but were otherwise unaffected until lambing. Only seven gimmers lambed without loss; in the remainder abortions and neonatal deaths accounted for 27 of the 31 lambs born. These losses occurred predominantly among gimmers which had been infected in mid pregnancy. Antibody titres in the toxoplasma indirect haemagglutination test rose sharply after the 10th day post infection and remained high for over 200 days. The majority of abortions and neonatal deaths occurred after the 40th day post infection by which time mean indirect haemagglutination titres had exceeded 1/320.

Abortion, Veterinary↗
PubMed1982

Toxoplasmosis in rams: possible significance of venereal transmission.

Three rams were infected with tick-borne fever eight months after infection with toxoplasma. There was no clinical evidence of reactivation of the latent toxoplasma infection and semen samples from the rams were not infective to mice. Semen samples from 77 apparently normal rams were tested for toxoplasma infection by passage through mice; none of the samples produced patent infections in mice. Two rams with chronic toxoplasma infection were repeatedly mated with seronegative ewes. None of the ewes showed serological evidence of acquired infection and all lambed satisfactorily.

Animals↗
PubMed1982

Experimentally induced toxoplasmosis in young rams: the clinical syndrome and semen secretion of toxoplasma.

Six rams were inoculated subcutaneously with 2000 toxoplasma tissue cysts. Semen samples from these rams, and from three uninfected controls, were screened for the presence of infective forms of toxoplasma. Three of the infected rams produced infective semen, each on two occasions, between 14 and 26 days post infection (pi). Five of the infected rams showed a febrile response from the fourth to 10th days pi and their indirect haemagglutination titres rose sharply from 10 days pi; the sixth ram was seropositive before infection and showed no clinical or serological response. In the experimental infection studied there were no symptoms or haematological changes of possible diagnostic value. The production of infective semen was restricted to a brief period shortly after infection although observations were continued for over 90 days. It was concluded that venereal transmission was unlikely to be significant in the spread of ovine toxoplasmosis.

Animals↗
PubMed1982

Perinatal changes in lambs infected with Toxoplasma gondii.

Twenty-one lambs, born to ewes experimentally infected with Toxoplasma gondii during pregnancy, which were either stillborn or died soon after birth, were examined for pathological changes. In the brain perivascular cuffing by lymphoid cells and distinctive focal inflammation was widespread and common. In addition, focal leucoencephalomalacia, often associated with haemorrhages, was found in almost half the cases examined. The livers from 14 of the lambs displayed large accumulations of lymphoreticular cells in portal triads and foci of extramedullary haemopoietic cells were present in 10. Among other tissues examined the adrenal gland in 14 cases was infiltrated by eosinophils which were often associated with macrophages that contained pigment with the staining characteristics of lipofuscin. In bone marrow the myeloid-erythroid cell ratio was significantly less than that in control animals. It is concluded that intrauterine infection of the ovine fetus with T gondii causes characteristic neuropathological changes in the fetus and that anoxia due to cotyledonary damage plays a significant role in the cause of death.

Adrenal Glands↗
PubMed1981

Influence of steroid-hormone-receptor-protein complexes on initiation of ribonucleic acid synthesis in liver nuclei isolated from rats of various ages.

The effect of age on the induction of the initiation of RNA synthesis was investigated in liver nuclei isolated from adrenalectomized rats of various ages after binding of a dexamethasone-receptor-protein complex. Binding of this complex to nuclear chromatin resulted in increased initiation of nuclear RNA synthesis at all ages; however, an age-associated decline in the extent of this induction was observed. This suggests an age-related decrease of total rat liver nuclear RNA synthesis with a decreased response to glucocorticoid hormones.

Adrenalectomy↗
PubMed1981

Plasma clot-promoting effect of collagen in relation to collagen-platelet interaction.

The hemostatic function of several acid-soluble collagen preparations and a fibrillar-form collagen preparation have been compared. Pepsin-treated acid-soluble collagen isolated from burro and horse aortic tissue and acid-soluble collagen isolated from human umbilical cord readily promoted platelet aggregation, but failed to activate the coagulation mechanism even after prolonged incubation with plasma at 37 C. By contrast, fibrillar-form collagen isolated from burro aorta was both an efficient stimulant for the induction of platelet aggregation and a potent clot-promoting agent. Similar results were found for all the collagen preparations irrespective of whether the studies were conducted with sheep or with burro plasma. Heat denaturation studies showed that the hemostatic function of the fibrillar-form collagen was dependent on an intact triple-helical structure.

Animals↗
PubMed1980

Age-associated changes in initiation of ribonucleic acid synthesis in isolated rat liver nuclei.

Initiation of RNA synthesis was studied in an attempt to determine a possible molecular mechanism for age-related biochemical and physiological changes. Initiation of RNA synthesis was determined by incorporation of [gamma-32 P]ATP and of [gamma-32P]GTP into an acid-insoluble product by intact nuclei isolated from livers of Sprague-Dawley CD-strain rats of various ages. When the rats were grouped into young (0.75-9 months) and old (12-30 months) rats, a significant decrease (P less than or equal to 0.001) in incorporation of initiating nucleotides was observed. The rat population was divided into five age groups (0.75-3 months, 4-9 months, 12-18 months, 19-23 months and 30 months) for further analysis of the effect of age on the initiation of RNA synthesis. Analysis of data from these groups indicated a significant trend for an age-related decrease in RNA-synthesis initiation (correlation coefficient = 0.94). Long-term hypophysectomy coupled with minimal hormone-replacement therapy was shown to have a significant effect on the reversal of the age-related decrease in initiation of RNA synthesis. It was observed that initiation of RNA synthesis in nuclei from 19-month-old rats, hypophysectomized at 12 months of age, was closest to that in 3-month-old intact rats and was not significantly different from that in liver nuclei of 0.75-9-month-old intact rats.

Adenosine Triphosphate↗
PubMed1980

Endogenous nucleotide pools and protein incorporation into liver nuclei from young and old rats.

To test the validity of estimating age-related changes in rat liver nuclear RNA synthesis by following the incorporation of radioactive nucleotides into an acid-insoluble product, age-related changes in endogenous nucleotide concentration were investigated. Both the total nucleotide and the nucleoside monophosphate (NMP) concentration decreased as a function of age. Although NMP concentration decreased linearly from 6 months of age, total nucleotide concentration decreased in an exponential manner beginning at 2 months of age. These age-related changes in endogenous nucleotide pool concentration cannot, therefore, be due to changes in nuclear permeability alone but may also involve age-related changes in nuclear metabolism of endogenous nucleotides. Since nuclear functioning proteins must be synthesized in the cytoplasm and subsequently incorporated into the nucleus, the effect of age on the uptake and specific incorporation of several of these proteins involved in transcription was investigated. There was no age-related difference in either the rate of uptake or in the total amount of general cytosol proteins, histones, ribosomal proteins or RNA polymerase incorporated by rat liver nuclei in vitro.

Aging↗
PubMed1980

Blood plasma magnesium, potassium, glucose, and immunoreactive insulin changes in cows moved abruptly from barn feeding to early spring pasture.

Cations and immunoreactive insulin in plasma were measured in 35 lactating cows moved abruptly to early spring pasture. After change of cows from grass-clover hay to fescue-bluegrass pasture containing 22 to 31 g potassium/kg dry matter, immunoreactive insulin of 5 Holstein cows increased 30% in 5 days and averaged 45% above prepasture concentrations for 40 days. Magnesium averaged 44% below prepasture content of plasma during this period and was correlated negatively with potassium -.17 and immunoreactive insulin -.37. Thirty Herford cows were changed from corn silage and grass-clover hay to wheat-rye pasture containing 3.06% potassium in the dry matter. Each day on pasture, 10 cows each were fed 2.3 kg cornmeal, 10 were given 30 g magnesium oxide by capsule, and 10 were given no supplement. After unsupplemented cows were moved to pasture, immunoreactive insulin rose 51% in 8 days and plasma magnesium fell 24%. Both supplements reduced immunoreactive insulin, but magnesium was maintained higher by magnesium oxide than by cornmeal. Injection of two Holstein cows with insulin (2 IU/kg body weight) reduced plasma concentrations of both potassium and magnesium 20% below that of two cows injected with only physiological saline. Whether elevated plasma insulin may accelerate development of hypomagnesemia in cattle on spring pasture with relatively high potassium content has not been established.

Animal Husbandry↗
PubMed1977

Further studies concerning the toxicity of ingested ergot sclerotia (Claviceps purpurea) to young and growing pigs.

In three experiments pigs were offered diets contaminated with milled ergot sclerotia. In a metabolism study 0-5 per cent (w/w) of American wheat ergot decreased urinary nitrogen losses and improved the efficiency of nitrogen retention. When early weaned piglets ingested a diet contaminated with 2-5 per cent of the ergot, feed intake was reduced and growth rate decreased. Reduction in growth rate was also evident in growing pigs given a diet containing ergotised English wheat. These latter pigs had lesions in stomach, intestine and liver, consistent with a toxic insult. With respect to feed intake and growth these results agreed with those of an earlier study, although a toxic response was produced by a lower dosage rate and there was additional internal evidence of toxicity. Improved nitrogen retention was contrary to earlier evidence at higher dose rates but may merely reflect a tonic action which, at higher doses, becomes toxic.

Animal Feed↗
PubMed1976

A complement fixation method for quantitative differentiation of reactions to 45/20 vaccine and Brucella infection.

Brucella complement fixing antibodies may be titrated independently in adult vaccinated (strain 45/20) and in naturally infected cattle by serological tests utilizing a specially prepared antigen. Serum samples are subjected to the standard complement fixation test for the diagnosis of brucellosis (MacKinnon 1963) and subsequently retested by the same method but with a saline extract antigen prepared from strain 45/20 Brucella abortus. The results obtained in the two tests are compared in five specific categories of brucella reactors. An evaluation and discussion of the test method, on the basis of the results obtained, indicates that informed diagnoses can be made in parallel with a continuous adult vaccination programme.

Animals↗
PubMed1976

"Bridging bronchus". A previously undescribed airway anomaly.

This report describes the clinical features and pathologic anatomy seen in an infant with anomalous bronchial branching and other congenital anomalies. The patient died of respiratory insufficiency and infection, possibly fostered by the malformed airway and a coexistent partial anomalous venous return. At autopsy, bronchial drainage of the right middle and lower lobes was provided by a large bronchial branch that originated in the left main-stem bronchus and bridged the mediastinum before entering the contralateral lung. Since crossed anatomic airway relationships after formation of primary branches are imcompatible with current concepts of embryologic lung development, a brief critical review of the pertinent literature is undertaken.

Abnormalities, Multiple↗
PubMed1976

Effect of glucagon infusion on plasma magnesium, glucose, and insulin in bull calves.

Two Holstein bull calves each were infused intravenously with 1 mg glucagon in .9% sodium chloride, and two were given saline alone; 1 wk later treatments were reversed. Glucagon increased concentrations of insulin and glucose but decreased potassium in blood plasma and moderately increased urinary magnesium and calcium losses. When only saline was used, there was no effect. A hypothesis relating elevated glucagon to grass tetany is proposed.

Animals↗
PubMed1976

Absorption, excretion, and tissue deposition of titanium in sheep.

Titanium metabolism was measured in three 18 kg lambs each fed 450 g chopped hay daily. Two of the lambs were dosed orally and one intravenously with 3 muCi titanium-44 each. Clearance of the intravenous dose was extremely slow; after oral administration, however, no titanium-44 was detected in blood plasma for 48 h. Over 96% of the oral dose was recovered in feces and digestive tract contents. Titanium-44 absorption, estimated from total carcass recovery and by comparison of concentrations in internal organs of orally and intravenously dosed lambs, was less than .5%. Fecal titanium could be a satisfactory index of soil ingestion by grazing ruminants.

Absorption↗