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Biomedical subjects

R A Nugent

Publications and source records attributed to R A Nugent.

At least 19 recordsLinked to original sources

Canine in vivo tracheal chemotaxis of eosinophils to antigen in sensitized dogs: inhibition by a steroid, a systemic lazaroid U-78517F, and several topical H1 antihistamines.

Inflammation of the airways contributes to the multicomponent disease known as asthma. The primary cells that infiltrate the airway in response to antigen exposure are neutrophils and eosinophils. Eosinophils have been implicated in much of the histopathology of the airway following infiltration and degranulation. We used topical antigen exposure in the trachea of sensitized beagle dogs to study the kinetics of eosinophil infiltration with a modified double balloon endotracheal tube technique. After establishment of the eosinophilia, we used inhibitors with known actions to implicate certain mediators in the cellular response. Beagle dogs were sensitized to ascaria ova by feeding them orally by gavage. After 6 wk, challenge with 2.0 micrograms/ml ascaris antigen protein via the tracheal chamber resulted in a rapid (maximal in 4 h) and repeatable influx (p less than 0.05 versus vehicle) of eosinophils that was faster and larger than that of exogenously added LTB4 or PAF exposure. After 4 to 6 separate (every 2 wk) antigen challenges in which the response varied by (SEM +/- 13 to 50%), the individual dogs were rechallenged in the presence of various inhibitors administered either topically in the perfusate or systemically. The inhibitors that were effective in blocking the eosinophil influx by a statistically significant amount were: (1) the lazaroid U-78517F orally 0.5 to 30 mg/kg-18 h (2) Medrol acetate 5 mg/kg intramuscularly-18 h, (3) H1-antihistamines topically (10(-6) M) Astemizole, Cetirizine, and Mepyramine, also orally 30 mg/kg, and Azelastine. Inhibitors falling to inhibit influx topically were a LTB4 receptor antagonist (U-75302) and U-80271 (Merck L-652731), a PAF antagonist.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance

Effects of alternative lamb production systems, maternal line, and culling strategy on flock age structure.

The 5-yr attrition of 1/4 (n = 411) or 1/2 (n = 403) Finnsheep (Finn) ewes exposed to terminal sire breeds in either an accelerated or semi-intensive annual lambing system was recorded to test the effects of system and percentage Finn on flock age structure at equilibrium. Ewes were culled for discernible ailments and failure to lamb after two consecutive non-spring exposures in yr 3, 4, or 5 only. Additionally, four progressively more intensive culling strategies for nonconception were practiced in retrospect. Flock productivity (kilograms of lamb weaned per ewe maintained per year) at age structure equilibrium was estimated for all culling strategies. The majority of all systems (cull strategy x lambing system x percentage Finn combination) were composed of ewes less than or equal to 3 yr old. Replacement requirements ranged from 24 to 38% in the accelerated system and 22 to 26% in the annual system. Quarter-Finns yielded greater replacement needs and shorter productive lives in accelerated lambing but fewer replacement requirements and longer productive lives than 1/2 Finns in annual lambing. Replacement requirements greatly increased with culling intensity in accelerated lambing (up to 54% above original levels) but only slightly in annual lambing (up to 8% above original levels). Mean (reproductive) lifetime estimated from fitted Weibull survival curves ranged from 3.1 to 5.1 yr in accelerated lambing and 4.5 to 5.4 yr in annual lambing. Increased culling for non-lambing decreased productivity at flock age structure equilibrium in accelerated lambing but did not change productivity in annual lambing. Repeatability of ewe effects on conception was generally low. Overall, system, percentage Finn, and culling strategy interact to influence system productivity through flock age structure. Intensive culling for non-lambing and replacement with ewe lambs of equal genetic merit should not be practiced in accelerated lambing systems.

Age Factors

Granulomatous orbital lesions: computed tomographic features.

Orbital lesions exhibiting granulomatous inflammation represent a heterogeneous group of diseases characterized by infiltration with epithelioid cells. The authors retrospectively reviewed the orbital computed tomography (CT) scans of 39 patients who had biopsy-proven lesions with granulomatous inflammation and found that diagnosis on the basis of CT was possible in only a few patients, those with a lesion of characteristic location and attenuation (such as a dermoid cyst) or characteristic distribution (such as bilateral enlargement of the lacrimal gland occurring in orbital sarcoidosis). In patients with multicompartmental disease exhibiting bone and extraorbital involvement the site of origin of the mass, the pattern of bone involvement and the clinical findings helped in classifying the cause of the lesion as Wegener's granulomatosis, a foreign body or mucormycosis. CT was crucial in determining the intraorbital and extraorbital extent of the lesion before excision or biopsy.

Adolescent

Intracranial extramedullary hematopoiesis. CT and bone marrow scan findings.

This case concerns a patient with intracranial extramedullary hematopoiesis (EH) suspected on a CT scan and subsequently confirmed with In-111 chloride and Tc-99m SC bone marrow scans. The bone marrow scans also provided additional information by demonstrating other sites of EH in the paravertebral tissues and bone marrow expansion into the distal extremities.

Adult

Carotid and vertebral artery trauma: clinical and angiographic features.

Injury to the carotid or vertebral artery is an important clinical entity that requires angiography for definitive diagnosis and evaluation. The common carotid artery may be injured by penetrating trauma while the internal carotid artery is usually damaged by either trivial or blunt trauma. With trivial trauma extracranial internal carotid artery dissection should be considered if there is unilateral headache, Horner's syndrome or delayed transient ischaemic attack, and intracranial dissection if a profound neurological defect occurs immediately following trauma. Injury to the internal carotid artery following blunt trauma includes dissection of the extracranial internal carotid artery, carotid-cavernous fistula and pseudoaneurysm formation. These should be considered in a patient with delayed neurological deficit, mandibular or skull fracture, a constellation of orbital signs or diffuse subarachnoid haemorrhage, respectively. Vertebral artery injury is less frequent. Dissection typically follows abrupt cervical rotation and occurs at C1-2, whereas penetrating trauma may involve either the proximal or distal vertebral artery and occlusion, arteriovenous fistula or pseudoaneurysm may be found. Endovascular techniques may be used in either the carotid or vertebral artery to close fistulae or occlude an extensively damaged vessel.

Adult

Effects of alternative lamb production systems, terminal sire breed, and maternal line on ewe productivity and its components.

The 4 yr productivity of 25% (QF; n = 533) and 50% (HF; n = 531) Finnsheep ewes exposed to either Suffolk or Columbia rams in one of three production systems was monitored to test the effects of system, terminal sire breed, maternal line, and their interactions on annual market lamb production. Ewe lambs and yearlings were randomly assigned to either a high-input accelerated lambing system (HIGH), a high-input annual system (MED), or a low-input annual system (LOW). Nursery facilities were available for weak lambs or those born in triplet or more births for the HIGH and MED but not for the LOW systems. Accelerated lambing protocol required early weaning. Sex-adjusted lamb weaning weights were corrected to within-system mean ages of 42 d for HIGH and 70 d for MED and LOW. The HIGH ewes weaned 1.55 lambs per year compared with 1.46 for MED and 1.18 for LOW (P less than .01). However, because of early weaning, HIGH yielded the lowest weight of weaned lamb per year. The MED ewes weaned 5.9 and 11.1 more kilograms of lamb per year than the LOW and HIGH ewes, respectively (P less than .01). The HIGH system may be economically feasible if young lambs could be inexpensively grown to feeder or market lamb weight. The HIGH ewes did not, however, increase lamb numbers in proportion to increased exposures compared with the annual systems. Breed-group effects for ewe productivity (kilogram of lamb weaned per ewe per year) were consistent across management systems, although some interactions among breed group and system were present for components of productivity. Suffolk rams yielded an advantage of 1.6 kg of weaned lamb per exposure over Columbia rams (P less than .05) due to a 3% better lamb survival (P less than .01) and heavier weaning weight, especially in the LOW system. The HF ewes weaned .1 more lambs per exposure than QF ewes (P less than .01); .06 of the lambs were nursery-reared. However, lambs from HF ewes had a 2% lower survival rate (P less than .05) and were 1.4 kg lighter at weaning (P less than .01), so overall productivity among HF and QF ewes was similar.

Animal Husbandry

Body measurements of newborn calves and relationship of calf shape to sire breeding values for birth weight and calving ease.

Body measurements on Angus- (n = 374) and Polled Hereford-sired (n = 438) calves were used to quantify calf shape via multivariate factor analysis, and measurements on Polled Hereford-sired calves were further used to investigate relationships between calf shape and sire expected progeny differences (EPD) for birth weight and first-calf calving ease. Calf birth weight, head circumference, shoulder width, hip width, heart girth, cannon bone circumference and length, and body length were recorded at 24 h postpartum. Sire birth weight EPD was positively associated (P less than .05) with all calf measures but only with head and cannon circumference after adjustment for phenotypic birth weight and gestation length. Thus, at constant birth weight, calves from higher birth weight EPD bulls tended to have larger cannon and head circumferences. Calving ease EPD was negatively related (P less than .05) to all calf measures except shoulder width. After adjustment for birth weight, only cannon circumference was associated with calving ease EPD, and this effect was removed by additional adjustment for birth weight EPD. Thus, at constant birth weight, bulls with higher EPD for calving ease sired calves with smaller cannon circumference, but at constant birth weight EPD, body measures were not associated with calving ease EPD. Factor analysis defined underlying skeletal width and frame components of shape (independent of birth weight) for both sire breeds. Calf shape differed among sires and was in part explained by birth weight EPD. No additional variation in shape was explained by calving ease EPD. Calf shape seemed to add no information for prediction of dystocia to that provided by birth weight EPD.

Animals

Body measurements of crossbred calves sired by Simmental bulls divergently selected for progeny first-calf calving ease in relation to birth weight.

Simmental bulls (n = 27) were divergently selected on linear model first-calf calving ease expected progeny difference (CEPD) relative to birth weight expected progeny difference (BEPD) so that body measures of calves from sires whose progeny tended to be born either with more or less dystocia than expected from BEPD could be obtained. At birth, calf weight, head circumference, shoulder width, hip width, heart girth, cannon bone circumference and length, and body length were recorded for 204 calves. These measures had also been obtained from the Polled Hereford X Angus dams of the calves at their births. Sire differences (P less than .05) existed for calf cannon bone circumference and length before and after adjustment for gestation length and birth weight of the calf. Sire BEPD was positively associated with cannon and head circumferences independent of phenotypic birth weight and gestation length. No relationship existed between CEPD or threshold model first-calf calving ease expected progeny difference and any calf measure, either before or after adjustment for birth weight. Multivariate factor analysis was used to describe independent components of skeletal width, frame, and thickness after removal of birth weight effects; factors were not related to genetic merit for calving ease or observed calving performance. Independent of weight, newborn calf measures were not highly related to body measures at weaning or to dam birth measures. Body shape differences at constant weight existed in crossbred calves, but they were not related to sire genetic merit for calving ease or measured dystocia. Selection for calf body shape, independent of birth weight, would not reduce dystocia.

Animals

Orbital lesions with granulomatous inflammation.

Orbital lesions characterized by granulomatous inflammation are a heterogeneous group of diseases of various causes with a common histopathological substrate involving aggregates of epithelioid cells. Forty-one patients (27 females and 14 males) with biopsy-proven granulomatous inflammation were seen at an orbital clinic between 1978 and 1989. The mean age at presentation was 40.2 (extremes 6 and 77) years. Two main clinical presentations were noted: painless, subacute or chronic mass effect, and tender, subacute inflammatory process. Six patients had secondary features that were infiltrative in character. The lesions were primarily located in the anterior superior orbit. In nearly half the patients the granulomatous reaction was confined to the orbit (predominantly ruptured dermoid and localized orbital sarcoid), and the remainder had either regional involvement (Wegener's granulomatosis or fibro-osseous process) or systemic involvement (sarcoidosis).

Adolescent

Orbital lymphangiomas: clinical, radiologic, and pathologic characteristics.

To assess the value of computed tomography (CT) in evaluation of orbital lymphangioma, the CT findings in 11 patients were retrospectively analyzed and correlated with the clinical, hemodynamic, surgical, and pathologic findings. The lesions were classified by location in three categories: superficial (n = 1), deep (n = 6), or combined (n = 6); the latter were evident earlier in life. The CT findings correlated well with the surgical and histologic findings. Orbital lymphangiomas were poorly defined lesions that crossed anatomic boundaries such as the conal fascia and orbital septum. Some degree of enhancement was the rule, ranging from scattered patchy areas to enhancement of the majority of the lesion. Areas of hemorrhage caused cystlike masses with rim enhancement. Preoperative identification of the vascular enhancing component at CT examination enables the surgeon to resect this area to prevent postoperative hemorrhage. High-resolution CT is of great value in the diagnosis and preoperative treatment planning of orbital lymphangioma.

Adolescent

Graves orbitopathy: correlation of CT and clinical findings.

The clinical and high-resolution computed tomographic (CT) findings in 71 patients (142 orbits) with Graves orbitopathy and 20 healthy patients (40 orbits) were retrospectively reviewed. The orbits with orbitopathy were subgrouped at clinical examination into those with (n = 18) and those without (n = 124) optic neuropathy. Mean extraocular muscle diameters and the calculated muscle diameter index were significantly increased in all orbits with ophthalmopathy, particularly in those with optic neuropathy. Graves orbitopathy affected the superior muscle group (63.4%) more than the medial (61.3%) or inferior (57%) recti. The most common pattern of muscle involvement involved all five measured extraocular muscles. Solitary muscle involvement most frequently involved the superior muscle group (6.3%). Significant enlargements of the retrobulbar optic nerve sheath and superior ophthalmic vein were noted only in orbits with optic neuropathy. Anterior displacement of the lacrimal gland at CT correlated with clinical palpability and occurred more frequently in patients with optic neuropathy. Severe apical crowding was the most sensitive indication of optic neuropathy at CT.

Female

Effect of cohabitation with white-faced ewes on estrous activity of Hampshire and Suffolk ewes exposed to rams in June.

Two groups of 24 Hampshire and 26 Suffolk purebred ewes each were used to study effects of cohabitation with cyclic white-faced (WF) ewes on estrous activity in June. Ewes lambed in January, February and March and had been isolated from mature rams since the previous fall breeding. From June 1 to July 2, treated (T) ewes were exposed to vasectomized rams and to 65 WF ewes; control (C) ewes were exposed only to vasectomized rams. Ovulation was assessed with biweekly serum progesterone assays; crayon marks were used to detect estrus. Daily observations of ram behavior were conducted to assess sexual activity of rams joined with T and C ewes. Cohabitation with WF ewes increased (P less than .01) ovulation percentages from 46% in C (42% for Hampshires and 50% for Suffolks) to 76% in T ewes (79% for Hampshires and 73% for Suffolks). Mating percentage also was increased (P less than .05) by cohabitation with WF ewes from 14% for C ewes to 30% for T ewes. Rams with T + WF ewes spent more (P less than .05) time checking ewes for estrus than did rams with C ewes. Hence, cohabitation with cycling WF ewes increased ovulation and mating percentages. Many acyclic T ewes first ovulated after 10 or more days of teasing, possibly due to increased ram contact in the presence of WF ewes.

Animals

Adult myelography with iohexol.

An open, multicenter trial of adult myelography was carried out at six centers in 117 patients with iohexol (Omnipaque) 240 mg I/ml and 300 mg I/ml to determine whether there was a difference in visualization or side-effects when a lumbar or cervical approach was used to visualize the areas where disease was suspected. One hundred and thirteen myelograms were analysable. In over 85% of the myelograms with a lumbar approach, visualization of the area injected was excellent or good. Just over half of these were obtained with the intention of visualizing primarily the cervical area, and in 93% of these visualization was good or excellent at that site. In 100% of the cervically injected myelograms, visualization was excellent in the cervical area. Areas more distant from the injections were well visualized in the majority of patients. There was no significant difference overall in visualization with either of the two concentrations of iohexol used. There were 59 side-effects, mostly mild in nature; 40 of them occurred in 50 patients receiving the higher concentration and 19 in 63 patients receiving the lower concentration. The most common side-effect was headache (23 patients). Nystagmus was the only severe side-effect and occurred in only one patient having cervical myelography. The patient made a complete recovery within 36 hours.

Blood Chemical Analysis

Dacryocystography: comparison of water-soluble and oil-based contrast agents.

Dacryocystography has been widely used in the assessment of the nasolacrimal duct system, particularly in patients with epiphora. Our study was undertaken to evaluate image quality and level of patient discomfort during examinations with water-soluble contrast agents (iohexol [Omnipaque 240], iopamidol [Isovue 200 and 300], and 52.7% diatrizoate meglumine and 26.9% iodipamide meglumine [Sinografin]) compared with the iodized oil-based contrast agent Lipiodol. Fifty-five dacryocystograms were obtained from 41 consecutive patients. The procedure was performed first with a water-soluble contrast agent, then repeated with Lipiodol. A distention technique was used with conventional radiography. Patients were asked to evaluate their level of discomfort (none, mild, moderate, severe). The images were evaluated separately by two radiologists, blinded to which water-soluble agent was employed, and the images were graded on a five-point scale. Images obtained with Lipiodol were significantly better than those with other agents (P less than .02), and image quality deteriorated as iodine concentration decreased. Use of Isovue 300 and Sinografin produced significantly more patient discomfort (P less than .03) than the use of other agents. The authors conclude that, in most instances, Lipiodol is the contrast agent of choice with regard to both highest level of patient comfort and greatest conventional radiographic image quality among the agents compared.

Contrast Media

Dysthyroid optic neuropathy. The crowded orbital apex syndrome.

The authors have reviewed the clinical presentation, visual fields, color vision testing, visual-evoked potentials, and computed tomographic (CT) findings of 58 patients (95 eyes) with dysthyroid optic neuropathy. The authors compared these findings to a control group of 60 patients (119 eyes) with thyroid eye disease who underwent CT scanning and did not exhibit evidence of optic neuropathy. Clinically, dysthyroid optic neuropathy is an insidious disease; when compared with the usual Graves' orbitopathy patient, the optic neuropathy group presented at a later age and with a later onset of thyroid eye disease. The patients in this group were more likely to be male and/or diabetic, and often presented with desaturation of color vision. Asymmetrical extraocular muscle restriction and vertical tropias were more frequent in the optic neuropathy group. The most sensitive indicators of optic nerve dysfunction appeared to be visual-evoked potentials and color vision. Computed tomographic studies confirmed that apical orbital crowding was a characteristic feature of optic neuropathy. These findings should alert the clinician to a more aggressive approach to these patients.

Adult

Effects of ewe breed and ram exposure on estrous behavior in May and June.

Two groups of purebred ewes (A and B), each consisting of 25 Dorsets and 25 Hampshires, were used to study effects of ewe breed and ram exposure on ovulation and estrus in May and June. Ewes lambed in January and February and were isolated from mature rams for at least 5 mo. From May 8 to June 11 (Period 1), Group A ewes were penned with vasectomized rams fitted with marking harnesses and Group B ewes were isolated from rams. From June 11 to July 13 (Period 2), rams were placed with Group B ewes and Group A ewes were isolated from rams. Ovulation was monitored by biweekly serum progesterone assays and crayon marks were used to detect estrus. For Group A ewes in Period 1, more Dorsets ovulated (96%) than did Hampshires (72%), and of ewes that ovulated, more Dorsets mated (83 vs 28%). Fifty-five percent of Dorsets, but only 20% of Hampshires, appeared to have been spontaneously cycling at the start of the experiment. Of ewes mated in Period 1, more Dorsets than Hampshires continued to cycle during Period 2 (65 vs 0%). For Group B ewes in Period 1, 44% of Dorsets, but only 8% of Hampshires, ovulated in the absence of rams. In Period 2, 92% of Dorsets and 84% of Hampshires ovulated. Of ewes that ovulated, more Dorset ewes mated (78 vs 52%). Of ewes that mated, more Dorsets appeared to be cycling spontaneously at ram introduction (39 vs 0%). Throughout the study, 24% of Dorsets, but no Hampshires, cycled continuously.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals