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Biomedical subjects

R J Thomas

Publications and source records attributed to R J Thomas.

At least 145 records · Page 8Linked to original sources
PubMed1981

The natural regulation of Trichostrongylus spp. populations in young grazing sheep.

The dynamics of Trichostrongylus axei and intestinal Trichostrongylus spp. were studied in grazing lambs over a 2-year period. Monthly comparisons were made between worm counts of experimental lambs continuously exposed to infection from 3 to 7 months of age, and tracer lambs which were allowed to graze on the experimental plots for successive 4-week periods. It was found that irrespective of the level of larval intake, experimental lambs were unable to regulate their worm burdens until at least 5 months of age. When larval intake was high, resistance to establishment of larvae apparently occurred at approximately 6 months of age followed by rejection and resistance to reinfection. In conditions of low larval intake, worms accumulated with no apparent control operating in lambs up to 7 months of age. These results suggest that a rapid turnover of worm populations does not occur in Trichostrongylus spp., and that in young lambs, worms accumulate until sufficient exposure to infection stimulates resistance to larval establishment and ultimately rejection of adults.

Animals↗
PubMed1981

The Assimilation of Ureides in Shoot Tissues of Soybeans : 1. CHANGES IN ALLANTOINASE ACTIVITY AND UREIDE CONTENTS OF LEAVES AND FRUITS.

The ureides, allantoin and allantoic acid, are major forms of N transported from nodules to shoots in soybeans (Merr.). Little is known about the occurrence, localization, or properties of the enzymes involved in the assimilation of ureides in shoot tissues. We have examined the capacity of the shoot tissues to assimilate allantoin via allantoinase (EC 3.5.2.5) during leaf and fruit development in nodulated soybeans. Specific activity of allantoinase in leaves peaked during pod formation and early seed filling. In developing fruits allantoinase activity in the seeds was 2 to 4 times that in the pods when expressed on a fresh weight or organ basis. In seeds, the embryos contained the highest specific allantoinase activity. Stems and petioles also had appreciable allantoinase activity. With development, peaks in the amounts of allantoic acid, but not allantoin, were measured in both leaves and fruits suggesting that the assimilation of allantoic acid may be a limiting factor in ureide assimilation. Highest amounts of ureides were measured in the pith and xylem of stem tissues and in developing pod walls.

Journal Article↗
PubMed1981

Examination of stockfeeds for Salmonella.

Of 100 stockfeeds examined for Salmonella 45 were positive by pre-enrichment followed by selective enrichment of 10 x 25 g samples. Forty-three were positive by selective enrichment of pooled aliquots of the pre-enrichment broths from the 10 x 25 g samples. Aliquots of the pre-enrichment broths from the 10 x 25 g samples of 77 of the feeds were stored at 4 degrees C and retested after 6 days. One hundred and ten of these (770) subsamples were found to contain salmonellas initially, and 107 were found to contain salmonellas after storage for 6 days. The testing of feeds by the examination of multiple 25 g samples and pooled pre-enrichment broths is recommended. Aliquots of the pre-enrichment broths may be stored at 4 degrees C for 6 days and retested if an estimation of the numbers in the feed is required. Further pre-enrichment after cold storage is not required.

Animal Feed↗
PubMed1981

The response of patients with fistulas of the gastrointestinal tract to parenteral nutrition.

Total parenteral nutrition is an effective form of therapy for fistulas of the gastrointestinal tract. In the series, reported mortality in unselected patients on total parenteral nutrition was 26 per cent. However, not all patients respond equally to total parenteral nutrition. Those less than 65 years of age, with nonmalignant disease or completely resected neoplasm have a close to 100 per cent fistula closure rate if no other significant disease is present. However, the elderly patient dies more easily, and there is little improvement in mortality with the use of total parenteral nutrition in this group. Patients with a fistula associated with residual intra-abdominal disease did poorly on total parenteral nutrition.

Gastrointestinal Diseases↗
PubMed1980

A survey of gastrointestinal parasitism in pigs.

Over a period of two years 180 pork pigs, 144 baconers and 144 sows from two slaughterhouses in northern England were examined for gastrointestinal parasites. Sows showed the highest level and intensity of infection, 85 per cent harbouring the dominant parasites Oesophagostomum dentatum and O quadrispinulatum; the highest worm burden recorded was 21,000. Hyostrongylus rubidus was present in 28.5 per cent of sows but virtually absent from younger pigs. Small numbers of Ascaris suum and Trichuris suis were recorded, 16 per cent and 23 per cent respectively in pork pigs and lower in older animals. Levels of parasitism appeared to be influenced by a number of management practices, in particular the housing system.

Animals↗
PubMed1980

Study of diaphyseal nutrient foramina in human long bones.

A study was done to determine the number, size, direction, exact site and position of the nutrient foramina in human long bones. The position of all nutrient foramina observed was on the flexor aspect and was more or less around a fixed area, but the exact spot varied considerably. Two foramina were much more frequent in the femur, clavicle and humerus than in the other long bones. Three and four nutrient foramina have also been observed in few femora, clavicles and ulnae. Absence of a foramen has been observed in few humeri and radii. Variations have been observed in the direction of nutrient foramina only in lower limb bones. The nutrient foramina in long bones have been described as being directed towards the elbow and away from the knee. Our observations support this assumption except in 0.5% femora, 3.5% tibiae and 9.5% fibulae. Periosteal, muscular and vascular theories are discussed for the normal and abnormal direction of the foramina; the vascular theory offers the best explanation of all reported anomalies as well as of the normal fashioning of the nutrient canals.

Adult↗
PubMed1980

Sequelae of arthrodesis of the hip.

Twenty-two patients with unilateral arthrodesis of the hip were reviewed clinically and radiologically ten years or more after operation. There was evidence of degenerative disease in 63.6% of the contralateral hips, 68.2% of the ipsilateral knees and in 59.1% of the contralateral knees. Both knees were affected in 50% of cases. All the patients had some degree of backache. The incidence of these problems in contrast with previously reported series is discussed.

Arthrodesis↗
PubMed1980

Wall regeneration by plasmolysed cells from tissue suspension cultures of Sphaerocarpos donnellii.

De novo synthesis of wall material by cells of Sphaerocarpos donnellii was followed using radioactive tracer techniques. Uniform uptake of [14C]glucose by plasmolysed suspension cultures was demonstrated autoradiographically. Liquid scintillation counts of acid- or alkali-soluble wall carbohydrates indicate that hemicellulose and cellulose make up the major wall fractions in control and plasmolysed tissues. The amount of label in walls of plasmolysed cells was significantly lower than in those of controls. Higher relative radioactivity in pectin and hemicellulose, and lower radioactivity in cellulose were found in plasmolysed tissue. These compositional changes may enhance wall stability by providing numerous sites for cross-linkage between cellulose microfibrils of regenerated walls.

Autoradiography↗
PubMed1980

The modifying effect of nutritional intake of the posttraumatic depletion in hepatic glycogen in rats.

Hepatic glycogen levels were measured in rats both on oral food ad libitum and where intravenous nutrition was supplied at 0.1, 0.2, and 0.35 Kcal/gm of body weigh/day at 24 and 72 hours after injury. While on oral food rats with a closed femoral fracture had a lower level (25 +/- 6.5 mg/gm of liver) than normal (66 +/- 9.1 mg/gm of liver, P less than 0.005), 24 hours after injury. There was a corresponding rise in blood sugar (161 +/- 20 leads to 240 +/- 23 mg/100 ml, P less than 0.005) at 24 hours. However the food intake fell (23.8 +/- 1.5 leads to 16.6 +/- 2.4 gm/day, P less than 0.01) during the first 24 hours after the injury. When intravenous nutrition was given at a caloric level of 0.35 Kcal/gm/day, hepatic glycogen levels were above normal and there was no difference between injured and noninjured animals. At 0.2 Kcal/gm/day there was also no difference between injured and noninjured animals, but glycogen levels fell from norman levels (78 +/- 12.9 mg/gm) to lower levels (33 +/- 11.9 mg/gm, P less than 0.01) over the 24-hour to 72-hour period. Low levels of caloric intake (0.1 Kcal/gm/day) resulted in a fall in glycogen level in both injured and noninjured animals, with the decrease being significantly greater in the injured animals. It is concluded that maintenance of the caloric intake of rats at normal or high levels via the intravenous route can prevent the depletion of hepatic glycogen produced by a femoral fracture.

Animals↗
PubMed1980

Efficacy of oxfendazole against Nematodirus battus and inhibited stages of sheep nematodes.

Oxfendazole administered at a dose rate of 5 mg/kg was 100 per cent effective against artificially acquired seven-day-old and 23-day-old infections of Nematodirus battus in lambs. At the same dose rate it was 100 per cent effective against naturally acquired infections of adult Trichostrongylus spp, adult and arrested early fourth stage larvae of Haemonchus contortus and Nematodirus spp. Efficacy against Ostertagia spp was 99 to 100 per cent against adults and 100 per cent against inhibited larvae, the predominant species of this genus being O circumcincta.

Animals↗
PubMed1979

Field observations on the epidemiology of abomasal parasites in young sheep during winter and spring.

A flock of spring born lambs was continuously exposed to natural parasite infection from birth until selected for slaughter in groups of two or three, at monthly intervals throughout winter and spring for abomasal worm counts. Meteorological data were recorded and regular estimates of infective pasture larval availability were made. Parasite population changes and inhibition patterns for Ostertagia spp, Haemonchus contortus and Trichostrongylus axei were recorded. Ostertagia spp were found to survive well both on the pasture and within the host, principally as arrested larvae. H contortus overwintered almost entirely in the host in the inhibited form and T axei overwintered mainly in the host, but in the adult stage.

Abomasum↗