Biomedical subjects
H M Acland
Publications and source records attributed to H M Acland.
Changes in fluid composition on the serosal surface of jejunum and small colon subjected to venous strangulation obstruction in ponies.
In 6 anesthetized ponies, 3 segments of jejunum and 3 segments of small colon were isolated from the peritoneal cavity in plastic bags filled with Hanks' balanced salt solution. One jejunal and 1 small colon segment were subjected to venous strangulation obstruction for 3 hours (VSO-3), venous strangulation obstruction for 6 hours (VSO-6), or a 6-hour sham procedure to control for changes induced by isolation in a plastic bag. Additional segments of jejunum and colon that were not placed in bags served as controls for histologic examination and collagenase measurements. Samples of fluid surrounding the intestine were obtained for chemical analyses, nucleated cell count, aerobic and anaerobic bacteriologic culture, and measurement of collagenase activity. Full-thickness tissue samples were obtained for histologic examination and measurement of collagenase content. Bacteria did not cross the intestinal wall after 3 and 6 hours of VSO, despite severe mucosal lesions in these segments. At 6 hours, PO2 was significantly less and PCO2 was significantly (P < 0.05) greater in the fluid surrounding the VSO-6 jejunal segments, compared with the sham jejunal segments. The pH was significantly (P < 0.05) less in fluid surrounding VSO-6 small colon segments, compared with the sham colon segments at 6 hours. For jejunum and small colon, phosphate and lactate concentrations were significantly (P < 0.05) greater in VSO-6 fluid than in the corresponding sham fluids at 6 hours. Fibrin formed around all VSO segments, although fibrinogen was not detected in the surrounding fluid, indicating possible rapid conversion of fibrinogen to fibrin.(ABSTRACT TRUNCATED AT 250 WORDS)
Neospora caninum (Apicomplexa) in a stillborn goat.
Tissue cysts of Neospora caninum were found in sections of brain from a stillborn pygmy goat. The tissue cysts had 1-2-microns-thick cyst walls and stained with anti-N. caninum serum in an immunohistochemical test. Glial nodules, mononuclear perivascular cuffing, and foci of inflammation were associated with N. caninum tissue cysts throughout the brain. This report indicates that N. caninum can be transmitted transplacentally in goats.
Primary teat neoplasia in two yearling heifers.
Two yearling heifers developed rapidly growing soft tissue masses attached to the base of the right hind teat. In each heifer, the solitary mass was raised, firm, and attached to the overlying skin. En bloc removal was accomplished in each by positioning the heifer in dorsal recumbency and by using local infiltration analgesia. Histologic examination revealed one of the masses to be fibroma and the other, fibrosarcoma. Neither tumor has recurred, and normal function of the teat was retained.
Mycobacterium avium serotype 4 infection of swine: the attempted transmission by contact and the sequence of morphological changes in inoculated pigs.
After 30 pigs were inoculated orally in groups at 4, 8, 12, 16 and 20 weeks of age with Mycobacterium avium serotype 4 and killed when approximately 210 lbs body weight, 24 pigs had gross lesions caused by M. avium and all had microscopic lesions. It was found that the group inoculated at 8 weeks of age had lesions that best reproduced those found in outbreaks of mycobacteriosis. Thirty-four contact pigs did not develop gross mycobacterial lesions and only 2 developed microscopic lesions. In a second experiment, 29 pigs were inoculated orally when 8 weeks of age and killed 6, 12, 18, 21 and 28 weeks later. Gross lesions caused by M. avium were present in 9 pigs and 17 pigs had microscopic lesions. Severe lesions were found in the pigs killed after 18 weeks. Gross lesions were enlargement or caseation of lymph nodes. Enlargement alone was not considered a reliable indicator of mycobacterial disease, as less than half the affected lymph nodes were histologically granulomatous. When a granulomatous lesion was present in enlarged lymph nodes, it was most likely to be an accumulation of epithelioid macrophages with areas of necrosis and caseation. The most common histological lesion found in grossly caseated lymph nodes was discrete granulomas with severe caseation and a thick fibrous capsule. Granulomas that consisted of epithelioid cells, or epithelioid cells and caseation were most numerous after 12 weeks or less. Multinucleate giant cells dominated the picture when the interval between inoculation and slaughter was 6 or 10.5 weeks. Encapsulated granulomas were the main type in animals inoculated 18 weeks or longer before slaughter. Caseation of epithelioid granulomas and the formation of multinucleate giant cells seemed to progress faster in the older inoculated animals. Microscopic granulomas were present in the tonsils and intestines of 8 pigs and 16 pigs, respectively, and most of these pigs were inoculated at 16 and 20 weeks of age and killed 10.5 and 6 weeks later. Lesions of the tonsil and intestine did not become encapsulated, and probably resolved. The conditions of our experiment should have allowed contact animals to be exposed to organisms shed from the tonsil and intestine of inoculated pigs, yet only a few microscopic lesions developed.
Pleural effusion secondary to metastasis of an ovarian adenocarcinoma in a horse.
An 11-year-old Quarter Horse mare was presented with ventral edema and pleural effusion, secondary to a disseminated ovarian adenocarcinoma. Bilateral thoracocentesis yielded 30 L of thin, blood-tinged fluid, which was a modified transudate. Cytologic examination of the fluid revealed large atypical cells, suggestive of carcinomatous neoplasia. Similar cells were found in the peritoneal fluid. The mare was euthanatized. Necropsy revealed a 35-cm diameter mass in the cranial mediastinum, ventral to the trachea. The left ovary was 25 cm in diameter and most of the parenchyma was replaced by red or brown friable tissue, containing numerous 1-to 3-mm cysts. Papillary adenocarcinoma of the ovary was diagnosed, based on the appearance and arrangement of tumor cells in the ovary, sublumbar and tracheobronchial lymph nodes, and mediastinal mass. Ovarian neoplasia should be considered in the differential diagnosis of pleural effusion in the horse.
Metastasis of bile ductule carcinoma in a cow.
An 8-year-old Holstein cow was referred with a history of weight loss, poor milk production, and hyperfibrinoginemia. Laboratory evaluation showed high gamma-glutamyltransferase activity, prolonged sulfobromophthalein clearance half-time, and prolonged prothrombin and partial thromboplastin times. Multiple firm nodules with histologic evidence of bile ductule carcinoma were found on exploratory laparotomy and liver biopsy. Pulmonary and lymph node tumor metastases were extensive. Tumor development in this case could not be associated with any of the known contributing factors in ruminants. This case demonstrates the extensive metastatic potential of this tumor and nonspecific signs with which bovine hepatic disease can be manifested.
Comparison of rectal mucosal cultures and fecal cultures in detecting Salmonella infection in horses and cattle.
Bacteriologic cultures of 65 rectal mucosal samples and 335 fecal samples from 53 horses and 5 cattle shedding Salmonella were performed. Salmonella spp were isolated from 34 (52%) rectal mucosal samples, 21 (32%) concurrent fecal samples, and 150 (45%) total fecal samples. The use of rectal mucosal samples when compared with concurrently obtained fecal samples significantly (P less than 0.025) improved the ability to isolate Salmonella spp. Concurrent bacteriologic culture of rectal mucosal samples and fecal samples resulted in 39 (60%) isolations. Compared with a series of fecal samples, Salmonella was isolated significantly more often when rectal mucosa and feces were cultured concurrently. Salmonella was isolated from rectal mucosal samples when it was not isolated from feces.
Congenital ethmoid carcinoma in a foal.
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Toxic hepatopathy in neonatal foals.
Six foals of three different breeds, born to healthy mares, appeared normal at birth, and died at two to five days of age with icterus, ataxia, head pressing, and terminal hepatic coma. Their livers were less than one-half normal weight. Most of the liver was dark red-brown and slightly rubbery. Histologically, these areas were characterized by severe bile ductule proliferation, mild portal tract fibrosis, and massive hepatocellular necrosis and lobular collapse. A small proportion of the liver, usually on the peripheral part of the lobes, was grossly light brown and slightly raised. Histologically, these areas had mild to severe bile stasis in canaliculi. In the thin marginal zone between the severely affected and mildly affected liver, there was mild bile ductule proliferation and periportal fatty change and necrosis. Alzheimer's type II cells, characteristic of hepatoencephalopathy, were numerous in the brains of all foals. Within two hours after birth, all the foals had been given an oral proprietary nutritional paste, the ingredients of which included a viable Aspergillus sp and an iron compound. Similar lesions were produced in an experimental foal.
Lesions in broiler and layer chickens in an outbreak of highly pathogenic avian influenza virus infection.
Fifteen chickens, five broilers and ten layers, from the Pennsylvania 1983 outbreak of highly pathogenic avian influenza virus infection, were examined. Gross lesions in the broilers were limited to serosal petechiae and dehydration. In the layers there was comb edema, vesiculation, and necrosis. Microscopic lesions were mild to severe diffuse nonsuppurative encephalitis, very mild to severe diffuse necrotizing pancreatitis, and very mild to severe subacute necrotizing myositis involving numerous skeletal muscles and most severe in the external ocular muscles and limbs. While many of these lesions have been seen in experimental infections of chickens with influenza viruses, the pattern of organs involved in this group of chickens is distinctive.
Comparison of uterine protein content and distribution of bacteria in the reproductive tract of mares after intrauterine inoculation of Haemophilus equigenitalis or Pseudomonas aeruginosa.
Two groups of 3 mares were inoculated with Haemophilus equigenitalis or Pseudomonas aeruginosa on the 1st day of estrus. Uterine flushing samples were recovered on day 3 of estrus and day 8 after ovulation for each cycle. Mares were killed 22, 25, and 30 days after inoculation with P aeruginosa and 45, 46, and 49 days after inoculation with H equigenitalis. Pseudomonas aeruginosa was recovered from the uterus of 2 mares 48 hours after inoculation. Although the initial flushing sample of 1 of these 2 mares had an increased total protein concentration, there appeared to be little difference between protein concentrations of other uterine flushing samples. Haemophilus equigenitalis was recovered from the uterus of each of the 3 mares at postmortem. One mare had a slight, purulent discharge from the vulva. Total protein values were not increased in flushing samples from this mare after inoculation with H equigenitalis. Total protein values decreased in the last flushing sample of each of the 2 remaining mares. Swabbing the uterus was more effective than was homogenizing the uterine mucosa in isolating H equigenitalis.
Abortion and stillbirth associated with Chlamydia psittaci var ovis in dairy goats with high titers to Toxoplasma gondii.
During two consecutive breeding seasons in a brucellosis-free dairy goat herd, approximately 40% to 70% of the does (mean herd size, 14.5) had stillbirths or aborted. None of the does aborted or had stillbirths twice. In the first breeding season, 9 of 13 does aborted in the last 2 months of gestation. Three fetuses and 2 fetal placentas from 2 does were examined. Microscopic findings included severe multifocal hepatic necrosis, mild pneumonia, and mild multifocal necrosis in the brain. Cultures for Listeria monocytogenes, Chlamydia psittaci, and Coxiella burnetii were negative. Paired sera from 3 of the does that had aborted or had stillbirths were tested for antibodies to Toxoplasma gondii. On the basis of high titers, a tentative diagnosis of toxoplasmosis was made. During the following breeding season, 6 of 16 does aborted during the last 2 months of gestation. A total of 6 fetuses and 4 fetal placentas from 5 of these does were examined. Microscopic findings included infiltration of mononuclear cells around hepatic vessels and multifocal necrosis and gliosis in the brain. Chlamydia psittaci was isolated from the tissues of 1 fetus, 2 aborting does had persistent, high antibody titers against C psittaci (1:160 and 1:320), and all except 2 other does in the herd had C psittaci titers of 1:20 to 1:40. All but 2 does had T gondii titers of 1:32 to 1:4096. Evidently there was mixed infection with C psittaci and T gondii in this herd, but the former organism probably was responsible for the abortions and stillbirths.
Clinical variations of border disease in sheep according to the source of the inoculum.
Non-cytopathogenic pestivirus obtained from lambs with border disease, with or without nervous signs, was inoculated into pregnant ewes at 57 to 65 days of gestation. Live lambs born to inoculated ewes were clinically identical to the lambs from which virus was obtained, ie, either a hairy birth coat with central nervous system disturbance or a hairy birth coat without central nervous system disturbance.
Multilobular osteoma (chondroma rodens) in a horse.
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Chondrosarcoma in a cow.
Chondrosarcomas are rare in cattle and none has been described in detail. A 30 cm diameter chondrosarcoma centred upon the costochondral junctions of the left 9th to 12th ribs of a 5-year-old Aberdeen Angus cow is described. In areas with a cartilaginous matrix the chondrocytes were plump, sometimes binucleate, sometimes bizarre, with occasionally 2 or more cells per lacuna. The other major matrix was loose and fibrillar, and the cells were spindle-shaped or stellate, with a moderate mitotic rate. Small areas appeared fibrosarcomatous. Both major types of matrix were present in the metastases, which extensively involved the pleura, intrathoracic lymph nodes and lungs. Less numerous and smaller metastases were present on the peritoneal surfaces and within several abdominal and pelvic organs. It is postulated that local extension of the tumour from the primary mass was followed by lymphatic spread to the lungs.
Pathology in the ovine foetus caused by an ovine pestivirus.
Homogenised tissues or tissue culture supernatant fluid containing a noncytopathic pestivirus obtained from a lamb with a neurologic form of border disease, were inoculated into ewes at different stages of pregnancy. Foetal death occurred in 9 ewes of those inoculated between 19 and 47 days of pregnancy while 3 ewes did not lamb. Eight of the foetuses were aborted between 77 and 132 days of pregnancy; of these 6 were autolysed or mummified and one had arthrogryposis. The one full-term dead lamb had a hairy birth coat and lissencephalic micrencephaly. Foetal death occurred in only 7 of 14 ewes inoculated between 57 and 72 days of pregnancy. Four of these ewes aborted between 77 and 108 days of pregnancy and 3 gave birth to full-term, dead, hairy lambs. The remaining 7 ewes gave birth to live hairy lambs with severe inco-ordination. All lambs carried to term and aborted foetuses or lambs that could be examined had a range of intracranial malformations including focal leucomalacia, micrencephaly, hydranencephaly, porencephaly, lissencephaly and cerebellar hypoplasia. Some lambs also had skeletal abnormalities including arthrogryposis, scoliosis and brachygnathia inferior. The pestivirus isolate used in these trials produced more severe effects on the ovine foetus than previously observed in similar inoculation trials using pestivirus isolates from border disease lambs without nervous signs.
Lesions of contagious equine metritis in mares.
Twenty-three mares were infected with contagious equine metritis organism by intrauterine inoculation, and necropsied after intervals of two to 116 days. Severe diffuse subacute salpingitis was seen in one mare, and mild multifocal subacute salpingitis was common. Severe diffuse endometritis and cervicitis initially were acute and became more severe, subacute and predominantly plasmacytic by 14 days, then declined but persisted as mild diffuse or multifocal inflammation for the rest of the experimental period. Vaginitis arose in parallel but resolved after 70 days. There were no lesions in the clitoral fossa or clitoral sinus.