A kinematic analysis of the instant centers of rotation analysis was performed on 21 metacarpophalangeal joints from 11 horses. Manual and computerized methods were used to locate the instant center of rotation on photocopies of transparent composite tracings of a series of radiographs of each joint. The instant centers of rotation of the proximal phalanx about the distal portion of the third metacarpal bone were located consistently on or near the eminence for attachment of the collateral ligaments. The instant centers of rotation of the sesamoids about the distal portion of the third metacarpal bone were consistently located near the dorsal articular margin of the distal portion of the third metacarpal bone. Rotation of the joint as it extended caused minor variation in radiographic projection. This variation in radiographic projection limited the precision of the analysis of the instant center of rotation and prevented the identification of a single instant center of rotation or an instant center of rotation pathway for the articulation of the proximal phalanx or the proximal sesamoids with the distal portion of the third metacarpal bone. The articular surface velocity vectors determined from the instant centers of rotation indicated that the joint surfaces slide on each other. The motion of the joint caused compression at the dorsal articular margins at maximal extension and thereby limited further extension. At this degree of extension, the proximal sesamoidsarticulated only with the proximal sesamoid-metacarpal articular surface of the distal portion of the third metacarpal bone.

A specialized tip structure in some mycoplasmas facilitates their attachment to host cells. Mycoplasma bovoculi strains FS8-7 and M165/69 did not have specialized membrane structure and did not exhibit capsule when stained with ruthenium red and examined by use of transmission electron microscopy. The organisms attached in vitro to bovine lung fibroblasts, with no apparent specialized structure. Attachment to conjunctival epithelium in vivo was observed (after death) in a calf infected with M bovoculi. Close association between M bovoculi and the host cells was noticed. Mycoplasmal cells pretreated with hyperimmune rabbit serum and labeled with protein A-gold complex had gold particles randomly distributed around the membrane. Gold-labeled monoclonal antibodies, M25.5 and M7.3, which were directed against 2 surface antigens of M bovoculi, also were distributed randomly on the mycoplasmal surface as seen in results of double-labeling experiments.

Cells acquired from lymph node biospy specimens obtained from 58 dogs scheduled to undergo chemotherapy for lymphoma were immunophenotyped, using a microlymphocytotoxicity (MLCT) assay comprising a panel of well-characterized monoclonal antibodies (MAB) specific for canine cell surface antigens. Cells from 54 of the dogs concurrently were tested cytofluorometrically, using surface immunoglobulin (SIg) as a marker for B cells and the MAB DT2 specific for peripheral blood T cells. The MLCT results indicated frequent coexpression of antigens identified by DT2 antibody and, to a lesser extent, by 1A1 antibody on SIg-positive cells, suggesting that these antigens may be associated with other types of less-differentiated lymphoid cells, in addition to being associated with mature T cells. Class-II major histocompatibility antigens, as recognized by MAB H81.98.71, HB10a, and H40.315.7, were detected on most SIg-positive cells, but generally were lacking on SIg-negative, DT2-negative cells. The MAB Wig4, reactive with canine monocytes, recognized relatively few cells (11 of 58). Response to chemotherapy was not correlated with reactivity to MAB DLy6 specific for resting lymphocytes or to MAB W3G10 specific for a polymorphic antigen associated with the canine major histocompatibility complex. The MLCT assay appears to be efficient, rapid, and inexpensive for immunophenotyping cells from lymphoma biopsy specimens.

Twelve Holstein calves mere used to determine the prophylactic efficacy of ivermectin against challenge exposure with gastrointestinal and pulmonary nematodes. Two groups of 6 calves (mean body weight, 205 kg) each were formed by restricted randomization according to body weight. Group-l calves served as nonmedicated controls. Each calf of group 2 was orally given one prototype sustained-release bolus designed to deliver ivermectin at a continuous daily dose of 8 mg. Third-stage nematode infective larvae were given to the calves on posttreatment days 28 and 42. The calves were euthanatized 77 or 78 days after treatment. Ivermectin was 100% effective (P < 0.05) in preventing the establishment of infection by Haemonchus placei, Ostertagia ostertagi, Cooperia spp (C punctata, C oncophora, C surnabada), Nematodirus helvetianus, Oesophagostomum radiatum, and Dictyocaulus viviparus and was > 99% effective against Trichostrongylus axei. Incidental infection by Trichuris spp was reduced by 94% (P = 0.08).

The umbilical arteries urachus, and umbilical vein were scanned ultrasonographically in 13 clinically normal foals that ranged in age from 6 hours to 4 weeks. Sonograms were obtained using a 7.5-MHz sector scanner transducer placed across the midline of the ventral portion of the foal's abdominal wall. The umbilical vein was scanned from the umbilical stalk to its entrance into the hepatic parenchyma. The mean (+/- SD) diameter of the umbilical vein was 0.61 +/- 0.20 cm immediately cranial to the umbilical stalk, 0.52 +/- 0.19 cm midway between the umbilicus and liver, and 0.6 +/- 0.19 cm at the liver. The urachus and umbilical arteries were scanned from the umbilical stalk to the apex of the urinary bladder and had a mean total diameter of 1.75 +/- 0.37 cm at the bladder apex. The umbilical arteries also were scanned along either side of the bladder and had a mean diameter of 0.85 +/- 0.21 cm. These measurements and the ultrasonographic appearance of the internal umbilical structures from clinically normal foals can be used as references to diagnose abnormalities of the umbilical structures in neonatal foals.

Strangulation obstruction was induced in anesthetized ponies for periods of 2 and 3 hours by clamping 45-cm segments of jejunum and associated veins (venous strangulation obstruction) and arteries and veins (arterial and venous strangulation obstruction). Four segments were studied in each of 7 ponies allowed to survive 12 hours, 2 segments in a pony that was allowed to survive 1 hour, and 1 segment in each of 10 ponies allowed to survive 42 days after the strangulation periods ended. Fifteen minutes after the periods of strangulation obstruction ended, the viability of test segments was assessed by clinical judgment (40 segments), fluorescein fluorescence (40 segments), and Doppler ultrasound (32 segments). Because thetest segments were normal at necropsy in long-term survivors, all segments were designated as viable. The overall accuracy of the methods used to predict viability was 88% for Doppler ultrasound and 53% each for clinical judgment and fluorescein fluorescence (P less than 0.005). Failures in the last 2 techniques could be attributed to their tendency to score venous strangulation obstruction segments as nonviable (90% for each). Doppler ultrasound was 94% accurate in these segments.

Dissection and injection studies in canine cadavers and in anesthetized dogs were conducted to determine the feasibility of using the latissimus dorsi, gracilis, and rectus abdominus muscles as musculocutaneous free flaps. Lengths of vascular pedicles for the latissimus dorsi (2 +/- 0.8 cm), gracilis (1.8 +/- 0.8 cm), and rectus abdominus (1.9 +/- 0.9-cm cranial deep epigastric, 1.7 +/- 0.5-cm caudal deep epigastric), as well as arterial diameters (1.28 +/- 0.31-mm thoracodorsal for the latissimus dorsi, 1.10 +/- 0.33-mm muscular branch for the gracilis, 1.25 +/- 0.25-mm cranial deep epigastric and 1.26 +/- 0.32-mm caudal deep epigastric for the rectus abdominus) were considered satisfactory for microvascular transfer. Fluorometry demonstrated overlying cutaneous perfusion in all flaps based on their muscle vascular pedicles, with the exception of the rectus abdominus flap based on the caudal deep epigastric artery. In this instance, up to 20% of the cutaneous element had questionable or no perfusion.

One-day-old turkeys were inoculated intranasally with Bordetella avium. Noninoculated hatchmates were housed separately. At postinoculation weeks 1,2,3,4, and 5, B avium-infected (BA+) and B avium-free (BA-) turkeys were necropsied; specimens of tracheas, intrapulmonary primary bronchi, and lung adjacent to primary bronchi were bacteriologically cultured. Lung tissue was collected for histologic examination. Lungs perfused with acetic acid were collected for evaluation to determine the size, number, and distribution of lymphoid nodules associated with primary bronchi. Bordetella avium was isolated from trachea and primary bronchi of all BA+ turkeys, but was never isolated from lung parenchyma. Acute purulent bronchitis was associated with colonization of the primary bronchi by B avium from postinoculation weeks 1 to 3. Macrophages and lymphocytes persisted in the peribronchial connective tissue for 5 weeks after inoculation. Bronchus-associated lymphoid tissue consisted of discrete lymphoid nodules protruding into the lumens of primary bronchi. Lymphoid nodules, morphologically similar in BA+ and BA- turkeys, were composed of nonciliated, cuboidal epithelium covering a zone of loosely arranged lymphocytes and macrophages and a deeper, sharply demarcated lymphoid follicle. Compared with bronchus-associated lymphoid tissue of BA- turkeys, lymphoid nodules of bronchus-associated lymphoid tissue in BA+ turkeys were more numerous and widely distributed along primary bronchi. In both BA- and BA+ turkeys, the mean diameter of lymphoid nodules doubled between 1 and 5 weeks of age.

Parasite-free, 4-month-old-calves were inoculated with Ostertagia ostertagi and/or Trichostrongylus axei, followed 6 weeks later by inoculation with increasing doses of O ostertagi for 8 weeks in the 2 groups (n = 9) of calves that had been given O ostertagi. Gastrin immunoreactivity concentration in serum was measured before and after infection and was correlated with changes in mucosal thickness. Gastrin immunoreactivity concentration in preinoculation control sera ranged from 95.2 to 287.1 pg/ml, and increased values were measured in all parasitized calves after 15 weeks. Significantly (P < 0.05) increased serum gastrin immunoreactivity concentration compared with the preinfection value, was found in calves infected with O ostertagi or T axei, and highly significant (P < 0.01) values were observed in calves infected with both parasites. Abomasal mucosal hyperplasia was observed in all parasitized calves; increased mucosal thickness and mucosal cross-sectional area were most prominent in calves infected with O ostertagi and T axei.

In the first of 2 separate trials, the efficacy of febantel, given at a dosage of 5 mg/kg of body weight, was assessed in calves with 60-day experimentally induced Bunostomum phlebotomum infection. Ten calves were given febantel paste, and 10 were given the vehicle only. All 20 calves were necropsied 7 days after cessation of treatment. Compared with untreated calves, febantel-treated calves harbored 99.4% fewer nematodes. In the second trial, the efficacy of ivermectin, given as a paste formulation at a dosage of 0.2 mg/kg, was assessed in calves with experimentally induced B phlebotomum infection. Ivermectin was given at 18 (n = 6) and 60 (n = 6) days after infection. At each treatment date, 3 additional calves were given vehicle only. At 67 days after infection, all calves were euthanatized. Efficacies of ivermectin against 18- and 60-day infections were 100 and 99.8%, respectively. Both anthelmintic preparations were easily administered, and adverse reactions were not observed.