Veterinary accomplices.
Explore the source record for details and available documents.
Animal Husbandry↗
Biomedical subjects
F Jackson
Publications and source records attributed to F Jackson.
Systemic release of a mast cell proteinase following nematode infections in sheep.
An enzyme-linked immunosorbent assay (ELISA) for sheep mast cell proteinase (SMCP) has been developed. Concentrations of SMCP in homogenates of abomasal tissue from parasite-immune sheep (341 micrograms SMCP/g tissues) were raised when compared to those in normal (non-infected) abomasa (0.145 micrograms SMCP/g tissue). SMCP was not detected in sera from normal animals challenged with Haemonchus contortus but was present (less than 1.0 ng SMCP/ml) in sera from 8/11 immune sheep 2 h after intra-abomasal challenge with 1 x 10(6) exsheathed Haemonchus larvae. In two further experiments, the SMCP response in gastric lymph was monitored after homologous larval challenge in sheep immune to Ostertagia circumcincta and in normal controls. SMCP (less than 1.4 ng SMCP/ml) was detected in lymph from 2/3 and 4/5 immune animals between 1 and 4 days post-challenge with 50,000 larvae, but not from normal animals. SMCP was not detected in lymph from immune animals following challenge with 1000 Ostertagia larvae. The relatively low concentrations of SMCP in blood and lymph reflect the presence of proteinase inhibitor(s) which interfered with the ELISA.
Abomasum↗
Mucosal IgA production and lymph cell traffic following prolonged low level infections of Ostertagia circumcincta in sheep.
Some aspects of the local immune response to daily challenge with 2000 Ostertagia circumcincta larvae were studied by monitoring changes in the composition of gastric lymph of naive and previously infected sheep. The main changes in the naive group were increases in lymphoblast output and concentrations of pepsinogen whereas lymph albumin values decreased markedly and IgA concentrations were usually unchanged. In contrast, in the previously infected sheep, the continuous challenge stimulated only transient increases in lymphoblast and IgA containing cell traffic whereas lymph IgA and pepsinogen concentrations remained elevated throughout the experiment. By temporarily interrupting the challenge in a second group of previously infected sheep it was shown that elevated IgA and pepsinogen values were maintained only if larval intake was continuous.
Abomasum↗
Prescribing postpartum iron supplementation: a survey of practicing obstetricians.
Supplemental iron (excluding the amount in prenatal vitamins) is routinely recommended post partum by standard obstetric textbooks. We surveyed practicing obstetricians in Maryland to examine their indications for and prescription of postpartum iron supplements. The survey was returned by 201 physicians (33% response rate). Iron was prescribed by 25% of the physicians always, 12% never, and 63% depending upon the patient. An average of 37% of postpartum patients were given iron. The most frequently cited indication for prescribing iron was the postpartum hematocrit level (used by 90% of the physicians), followed by high blood loss (41%), operative delivery (15%), mean corpuscular volume (12%), and toxemia (9%). The postpartum iron dosage (325 mg) was prescribed as a single daily dose by 22%, twice daily by 37%, and three times daily by 32%. These practices do not correspond to the current recommendation that postpartum iron should always be prescribed.
Decision Making↗
Effect of concurrent infection with Ostertagia circumcincta and Trichostrongylus vitrinus on the performance of lambs.
The interaction between Ostertagia circumcincta and Trichostrongylus vitrinus was investigated in lambs continuously infected over 12 weeks. Four groups of seven lambs were given either zero, 1000 T vitrinus larvae per day, 2500 O circumcincta larvae per day or infected concurrently. Overall liveweight gain was reduced by 17, 20 and 30 per cent in T vitrinus, O circumcincta and concurrent infection, respectively. T vitrinus infection significantly lowered serum phosphorus concentrations by week 4. In the concurrent infection the decline in phosphorus concentration was more gradual and only differed significantly from the controls during the final four weeks of the trial. There were no significant differences between the total numbers of T vitrinus or O circumcincta recovered from single or combined infections. The lack of an additive effect on performance may be due to a delayed establishment of T vitrinus in the presence of O circumcincta.
Animals↗
Computer assisted tomography of the apophyseal changes in patients with ankylosing spondylitis.
We have examined the appearances by computed tomography of the apophyseal joints in 28 patients with ankylosing spondylitis (AS), as well as in 10 patients with noninflammatory lumbar disease. The number of changes noted in the apophyseal joints in each patient correlated significantly with the degree of restriction of spinal flexion seen (p = 0.002), but did not correlate with the clinical duration of disease (p greater than 0.2). No specific abnormalities were seen in patients with AS that were not also noted in the non-AS subjects.
Adult↗
Transfer of immunity to Ostertagia circumcincta and IgA memory between identical sheep by lymphocytes collected from gastric lymph.
Sheep rendered immune to Ostertagia circumcincta were challenged with 50,000 larvae and lymphocytes were collected from the gastric lymph up to eight days after challenge. The cells were transferred intravenously to genetically identical worm-free sheep which, together with controls, were challenged with 50,000 larvae and killed nine days later. Cells obtained during the donors lymphoblast response to challenge transferred partial immunity, measured either as stunting or loss of worms. Significantly less immunity was transferred by cells collected either before or after this response. Thus the responding cells can mediate protective immunity to O circumcincta. On the other hand the donor sheep remained immune to their challenge infection despite being depleted of these functional cells, showing that their presence was not essential for immunity to be maintained. Comparison of the immunoglobulin A (IgA) concentrations in the gastric lymph of recipient and control sheep showed that a local IgA response had also been transferred. Enumeration of mucosal mast cells suggested that a mastocytosis had been transferred to the two recipients which were most immune to challenge.
Animals↗
Independent co-release of acetylcholine and somatostatin from cardiac vagal neurones in toad.
Vagal postganglionic neurones in toad (Bufo marinus) cause cardio-inhibition by releasing both acetylcholine and somatostatin. In isolated, electrically paced, toad atria, intracardiac neurones were stimulated by short bursts of high-voltage pulses applied during the atrial refractory period. Treatment with hemicholinium-3 (5 X 10(-4) M) for 5 h eliminated most of the acetylcholine-mediated cardio-inhibition but did not inhibit somatostatin-mediated transmission. It is concluded that somatostatin release does not depend on the simultaneous release of acetylcholine.
Acetylcholine↗
Serum theophylline--a mandatory measurement in the control of therapy?
Explore the source record for details and available documents.
Adolescent↗
Age immunity to Ostertagia circumcincta: comparison of the local immune responses of 4 1/2- and 10-month-old lambs.
In 2 experiments, the local immune response to infection with 50,000 O. circumcincta was monitored in 4 1/2-month-old previously infected lambs by following changes in the composition of gastric lymph. The previously infected lambs were partially resistant to the challenge in that they harboured a greater proportion of early fourth stage parasites and that the developing larvae recovered from them were distinctly shorter than those present in controls. They also exhibited a secondary local immune response in the gastric lymph consisting of increases in the output of lymphoblasts and IgA cells which peaked 3 to 5 days after challenge, followed by increases in lymph IgA and IgA anti-larval antibody on days 6 and 7. The size of the total IgA response in a sheep was highly correlated with the degree of stunting of its larvae, suggesting that IgA antibody can reduce the growth of developing Ostertagia. When compared with the results of 2 identically designed experiments carried out previously in 10-month-old sheep, the younger lambs were measurably less resistant to challenge and most aspects of the magnitude of the local immune response were significantly depressed, although the timing of the response was similar. It is suggested that this poorly developed ability to mount a secondary mucosal immune response may explain the relative failure of the younger lamb to develop resistance to gastro-intestinal nematodes.
Aging↗
Effect of experimental Ostertagia circumcincta infection on the performance of grazing lambs.
Groups of 10 three-and-a-half-month-old Suffolkcross lambs were infected daily, five times a week, for 12 weeks with either zero, 500, 1500, 3000 or 5000 larvae of Ostertagia circumcincta and grazed together on a series of 'clean' paddocks. All the lambs were moved at seven to 10 day intervals to a fresh paddock to prevent autoinfection and were killed after 14 weeks. Another group was killed at the outset as a control for carcase analysis. Mean O circumcincta populations were 34 (grazing control) and 1224, 473, 1092 and 4331 for the groups receiving 500, 1500, 3000 and 5000 larvae per day respectively. The percentage of fourth stage larvae increased with increasing larval intake. Extensive abomasal damage with mucosal hypertrophy and depletion of parietal cells occurred in the lambs receiving 3000 and 5000 O circumcincta larvae per day. Intakes of 1500 larvae per day and above depressed growth rate by 24 to 37 per cent, reduced the deposition of protein in the carcase by 34 to 52 per cent and lowered calcium/phosphorus deposition by 23 to 48 per cent. Plasma pepsinogen concentrations were consistently elevated in lambs receiving 3000 or 5000 larvae per day and may be a useful aid to recognising abomasal damage sufficient to affect productivity.
Abomasum↗
Effect of Ostertagia ostertagi on lamb performance and cross resistance to O circumcincta.
Fifteen worm-free lambs (two-and-a-half to three months or four to four-and-a-half months old) were infected with 3500 or 4000 Ostertagia ostertagi larvae on five days each week for six weeks, and their performance compared to that of controls. Eleven lambs were killed after eight weeks and four were challenged with O circumcincta to determine whether any cross resistance had developed. A feature of the O ostertagi infection was the considerable variation in response. Overall liveweight gain was lowered by 24 per cent in the two-and-a-half to three-month-old infected lambs, mainly due to reductions of 27 to 40 per cent in four of the seven lambs. There was no consistent effect in the older lambs. The worm populations consisted mainly of early fourth stage larvae and developing worms, but a small percentage reached sexual maturity and these produced a low faecal egg count (1 to 63 eggs per gram). Numerous intraluminal refractive crystals were present in the gut of both adult worms and developing stages, possibly reflecting degenerative changes. Hypertrophy of the abomasal mucosa with patchy loss of differentiation was a feature of the infection, and in four lambs serum pepsinogen concentrations were elevated. Exposure to O ostertagi did confer some protection against challenge with O circumcincta in that worm counts were reduced to about 60 per cent of those in controls, although no increase was observed in the numbers of arrested larvae. The successful passage of O ostertagi through young lambs could be important in mixed or alternate grazing systems by providing a reservoir of infection for the alternate host.
Animals↗
Manifestations of resistance to ovine ostertagiasis associated with immunological responses in the gastric lymph.
Groups of previously infected and worm-free sheep were serially killed up to 10 days after challenge with 50 000 Ostertagia circumcincta larvae. Two similar groups of sheep were killed 10 days after challenge with 1000 larvae. The previously infected sheep were resistant to the smaller challenge dose in that fewer, stunted worms were recovered from them than from controls. However, this resistance was not as marked as that observed in the previously infected sheep which received the large challenge, because proportionally fewer worms were recovered after the 50000 dose and the great majority of these were arrested at the early fourth stage. The gastric lymph ducts of 6 previously infected sheep were cannulated successfully and a marked local immune response was detected in 3 sheep which were challenged with 50 000 larvae. No response was detected in 3 cannulated sheep challenged with 1000 larvae. In the lymph of the 50 000 dose group, a temporary increase in pepsinogen activity suggested that a hypersensitivity reaction related to the presence of large numbers of mucosal mast cells began between 24 and 48 h after challenge. This was followed by marked increases in the cellular and IgA content of lymph, which reached peaks on days 3 and 6, respectively. It is suggested that the response detected in the gastric lymph reflected aspects of a local immune reaction in the abomasal mucosa and that this reaction accounted for the enhanced degree of resistance to the larger challenge dose.
Animals↗
Comparison of saline incubation and pepsin digestion as methods for recovering Ostertagia circumcincta larvae from the abomasum of sheep.
Incubation in saline at 37 degrees C was compared with pepsin digestion as a quantitative method for recovering larval stages of Ostertagia circumcincta from the abomasal mucosa of sheep. Experiments showed that the techniques were of roughly similar efficiency even when the larvae were arrested but that the saline method was preferable because worm searching was easier and quicker.
Abomasum↗
Further observations on faecal egg output in lambs dosed continuously with Ostertagia circumcincta.
The relationship between size of intake of infective larvae of Ostertagia circumcincta and faecal egg output by lambs was examined in two experiments in four-month-old Suffolk cross lambs dosed five times per week for 10 weeks. The first experiment compared two strains, Weybridge and Moredun, at two levels, 400 and 4000 per dose. The second experiment compared two levels, 40 and 400 per dose, of Moredun larvae. The group mean output of worm eggs was almost unaffected by the 10-fold reduction in intake from 4000 to 400. The further reduction from 400 to 40 reduced egg output by a factor of 2.5.
Animals↗
Resistance to Haemonchus contortus transferred between genetically histocompatible sheep by immune lymphocytes.
The pattern of faecal egg counts after infection with 10,000 Haemonchus contortus larvae was similar within but not between, four pairs of monozygous twin sheep. Transfer of whole lymph or washed lymph cells from three immune donor sheep to their identical co-twin recipients reduced the susceptibility of the recipients to challenge with 10,000 larvae as measured by faecal egg counts. Cells from a nonimmune donor did not have this effect. In a final experiment, washed cells from an immune triplet sheep, which was actively responding to a repeated challenge infection, transferred a secondary local IgA response to a second recipient triplet and resulted in a marked reduction in worm count when compared with that of a third infectivity control triplet.
Animals↗