Factors enhancing diacylglycerol acyltransferase activity in microsomes from cell-suspension cultures of oilseed rape

Several factors, including an unidentified endogenous component, were found to stimulate microsomal diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) from a microspore-derived cell-suspension culture of oilseed rape (Brassica napus L. cv. Jet Neuf). At a concentration of 25 mM, MgSO4 and MgCl2 stimulated microsomal DGAT 25- and 10-fold, respectively. ATP and CoA at concentrations of 2 and 1 mM stimulated the enzyme 2.4- and 12-fold, respectively, although the effects were lessened in the presence of higher Mg2+ concentrations. Although microsomal DGAT activity was increased only slightly by the addition of exogenous sn-1,2-diacylglycerol to the reaction mixture, it was increased substantially by the addition of exogenous phosphatidate. sn-Glycerol-3-phosphate and other phospholipids tested did not have this stimulatory effect. DGAT activity did not decrease when microsomes were incubated with ATP in the presence of the cytosolic fraction. This fraction, however, contained a small organic compound(s) that stimulated microsomal DGAT activity.

Skin lesions caused by orthopoxvirus infection in a dog

A seven-year-old male dobermann was presented for examination of a non-pruritic ulcerated lesion occurring at the site of a suspected rat bite on the muzzle. Biopsy revealed focal ulcerative dermatitis, with cells in the epidermis, follicular infundibula and interposed sebaceous glands undergoing ballooning degeneration and containing large acidophilic intracytoplasmic structures resembling poxvirus inclusion bodies. The diagnosis of orthopoxvirus infection was confirmed by transmission electron microscopy and immunohistochemistry. The biopsy site healed uneventfully, without evidence of recurrence or development of further cutaneous or internal lesions, and a serum sample collected eight weeks after first presentation had a low titre of poxvirus antibodies. This report demonstrates that orthopoxvirus infection should be considered as a cause of ulcerative skin lesions in dogs, particularly if there has been recent contact with rodents or other small mammals.

Synovial myxoma: magnetic resonance imaging in the assessment of an unusual canine soft tissue tumour

Magnetic resonance imaging (MRI) of the hindlimb of a 10-year-old Labrador retriever was performed preoperatively to define the limits and invasive nature of a synovial myxoma. This unusual tumour in dogs has also only rarely been reported in humans, although the use of advanced imaging techniques has been more widely reported in the assessment of soft tissue tumours in people. MRI was an invaluable aid in the delineation of the extensive pathological changes associated with this tumour and consequently its surgical treatment. Amputation was performed and the dog remained disease-free 18 months after surgery.

Recombinant hyaluronate associated protein as a protective immunogen against Streptococcus equi and Streptococcus zooepidemicus challenge in mice

The capsule of Streptococcus equi, the cause of strangles, and Streptococcus zooepidemicus, associated with equine lower airway disease, plays an important role in evasion of phagocytosis by polymorphonuclear leucocytes. It is composed of hyaluronate, making it non-immunogenic. A hyaluronate associated protein (HAP) from S. equisimilis, whose gene has been sequenced [1], was investigated (a) for its presence in S. equi and S. zooepidemicus and (b) as an immunogen able to interfere with capsule structure and protect against experimental challenge of mice. The purified capsule of S. equi contained a protein of similar molecular mass to the S. equisimilis protein (approximately 53 kDa). Polymerase chain reaction (PCR) using primers derived from the published sequence of S. equisimilis HAP yielded a product from S. equi and S. zooepidemicus of the expected size and susceptibility to restriction endonucleases. Subcloning of two large in frame StuI/SspI fragments of the HAP gene from S. equi, approximately equivalent to the two halves of the molecule, into the expression vector pGEX-3X yielded only the carboxy half in the correct orientation. This latter recombinant produced a GST fusion protein (HAP-GST) of the expected size that was affinity purified. Antibodies in rabbit antiserum to the native protein in purified hyaluronate reacted strongly in immunoblots with HAP-GST. Antiserum to HAP-GST, when soaked into filter paper strips, caused a diminution of capsule production by S. equi cultured on blood agar. Antiserum added into fresh rabbit blood was not opsonic for S. equi. Immunization with HAP-GST significantly reduced rhinitis in Balb/C mice challenged nasally with S. equi and significantly increased survival time and clearance of bacteria in CBA/CA mice challenged intraperitoneally with S. zooepidemicus.

Haemochromatosis gene C282Y homozygotes in an elderly male population

We found that C282Y homozygosity was not under-represented in an elderly male population. This suggests that life-threatening, haemochromatosis-related disease may not occur in many C282Y homozygotes.

Abattoir survey of acquired reproductive abnormalities in ewes

Abnormalities of the reproductive tract of female sheep were studied by examining 9970 reproductive tracts from cull ewes and 23,536 tracts from nulliparous sheep (prime lambs) over a period of 12 months in abattoirs in south-west England. Overall, 3.37 per cent of the tracts were pregnant (8.11 per cent of cull ewes, and 1.36 per cent of nulliparous sheep), with a peak incidence between September and December. A total of 655 ewes (6.57 per cent) and 459 nulliparous sheep (1.95 per cent) had acquired abnormalities of the reproductive tract. Within these totals, abnormalities of the ovaries accounted for 3.51 per cent (for the ewes) and 10.68 per cent (for the nulliparous sheep) of all the abnormalities, and abnormalities of the ovarian bursa and uterine tube accounted for 42.1 per cent (for the ewes) and 5.23 per cent (for the nulliparous sheep). In addition, uterine lesions (hydrometra and metritis) accounted for 9.92 per cent (for the ewes) and 13.51 per cent (for the nulliparous sheep); lesions of the cervix and vagina (total of 1.44 per cent) and Cysticercus tenuicollis cysts associated with the reproductive tract (total of 3.05 per cent) were less common. Among the ewes the most common ovarian lesions were ovulation tags, and follicular cysts were the most common in nulliparous animals. Lesions such as bursitis, parametritis and abscesses of the reproductive tract were much more common in cull ewes than in nulliparous sheep, probably having arisen from peripartum infections. Hydrosalpinx and hydrometra, in which the intraluminal fluid was clear, were present at relatively high incidence in nulliparous animals, but not in cull ewes. The proportion of tracts containing macerated fetal remnants (2.14 per cent of all abnormalities in cull ewes) was lower than expected. It was considered that the functional significance of many of the lesions, such as ovulation tags and C tenuicollis cysts, was likely to be low, although in some cases of the latter calcification of the cyst had occluded the uterine tubes. Other lesions, notably hydrosalpinx, bursitis and metritis were likely to have made the affected animals sterile. The acquired abnormalities were therefore more significant in terms of individual animal infertility than as a major cause of infertility in flocks.

Abattoir survey of congenital reproductive abnormalities in ewes

A survey of abnormalities of the reproductive tract of female sheep was undertaken at two abattoirs in the south west of England over a period of 12 months. During the survey, 9970 reproductive tracts from cull ewes and 23,536 tracts from nulliparous sheep (prime lambs and hoggets) were examined. A total of 655 (6.57 per cent) ewes and 459 (1.95 per cent) nulliparous sheep had abnormalities of the reproductive tract. Of these, congenital abnormalities of the paramesonephric ducts accounted for 2.4 per cent of the ewes and 7.4 per cent of the nulliparous sheep, congenital abnormalities of the ovaries accounted for 2.6 per cent of the ewes and 7.4 per cent of the nulliparous sheep and cystic structures that were considered to have been of congenital origin accounted for 27.2 per cent of the ewes and 52.7 per cent of the nulliparous sheep. The most common lesion was paraovarian cysts (26.6 per cent of ewes and 39.0 per cent of nulliparous sheep), but few of these appeared to have affected the sheep's reproductive function. Several specific conditions were recorded, including some described for the first time in sheep. Uterus unicornis occurred in 20 sheep and other forms of segmental aplasia of parts of the paramesonephric ducts occurred in a further 13 animals. Uterus didelphys occurred in six sheep, and 11 animals were intersex. Intersex sheep had vestigial structures that were derived from the paramesonephric ducts, hypoplastic or masculinised gonads and some had masculinised external genitalia. Ovarian hypoplasia occurred in 34 sheep, and in a further 12 mainly nulliparous animals, the ovaries were fused. Sixty nulliparous animals and two ewes had hydatids of Morgagni.

Systemic infection by equid herpesvirus-1 in a Grevy's zebra stallion (Equus grevyi) with particular reference to genital pathology

A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto undescribed aspects of the pathogenesis of naturally occurring EHV-1 infection in the male equine genital tract. Restriction digests of the isolate demonstrated a pattern similar to that of EHV-1 isolates previously recovered from aborted zebra and onager fetuses.

Equivocal notions of accuracy and genetic screening of the general population

The explosive growth in genetic technology quickly will make possible an unprecedented number of tests for genetically based conditions. A necessary condition for the use of such tests without risk of harm to the patient is their accuracy. However, most discussions of test accuracy in the literature have equivocated between two importantly different meanings of the word. In particular, it must be remembered that a high analytic accuracy does not imply a high diagnostic accuracy. Questions about the diagnostic accuracy of genetic tests presently loom large because of our limited knowledge of the complex etiology of disease and the distribution within the general population of the causal factors involved. Our current inability to supply patients with accurate diagnosis based on genetic information, however, is less problematic when examined in the context of new reproductive technologies such as in vitro fertilization and intraplasmic sperm injection.

Use of transabdominal ultrasound-guided amniocentesis for detection of equid herpesvirus 1-induced fetal infection in utero

OBJECTIVE

To evaluate transabdominal ultrasound-guided amniocentesis for detection of equid herpes-virus 1 (EHV-1)-induced fetal infection in utero.

ANIMALS

4 Welsh Mountain mares.

PROCEDURE

Pregnant mares were inoculated intranasally with EHV-1 during the ninth month of gestation. Amniocentesis was initiated on postinoculation day (PID) 12, and was performed at 2- to 3-day intervals in standing mares under deep sedation. Amniotic fluid samples were tested by virus isolation (VI), polymerase chain reaction (PCR), and immunoperoxidase cytologic examination (IC) for detection of EHV-1.

RESULTS

Exposure to EHV-1 in the ninth month of gestation resulted in nasal shedding of infective virus, establishment of cell-associated viremia, and seroconversion. Equid herpesvirus 1 was detected by VI, PCR, and IC in amniotic fluid collected on PID 14 from 1 mare and on PID 16 and 17 from a second mare. Specimens of amniotic fluid from a third mare were VI negative until PID 18, when collections ceased, although this mare subsequently aborted an EHV-1-infected fetus on PID 28. The fourth mare aborted an EHV-1 infected fetus on PID 14. The 2 mares with VI-positive amniotic fluid were each carrying an EHV-1 infected fetus in utero, confirmed by examination of the uterus, placenta, and fetus, using specific immunohistochemistry and in situ hybridization. Endothelial cells in the endometrium and allantochorion were often virus-infected, with accompanying vascular lesions. The fetus had been infected via the chorionic vasculature in the first and fourth mares, and by inhalation of infected amniotic fluid in the second mare.

CONCLUSION

Amniocentesis permits specific detection of EHV-1-induced fetal infection in utero.

CLINICAL RELEVANCE

Amniocentesis may have a clinical role in the specific identification and isolation of mares carrying virus-infected fetuses during EHV-1-induced abortion epizootics.

Herpesviral abortion in domestic animals

Abortion or neonatal disease may follow infection with several alpha, beta and gamma-herpesviruses. The alpha-herpesvirus, equid herpesvirus-1 (EHV-1), causes single or epizootic abortions or neonatal deaths in equids, and the closely related virus EHV-4 causes sporadic equine abortions. In cattle, the alpha-herpesviruses, bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) and bovine herpesvirus-5 (bovine encephalitis virus), and a gamma-herpesvirus, bovine herpesvirus-4, have all been implicated as causes of abortion. In pigs, suid herpesvirus-1 (SHV-1: pseudorabies virus), an alpha-herpesvirus, and SHV-2 (porcine cytomegalovirus), a beta-herpesvirus, each cause abortion or neonatal piglet losses. Caprine herpesvirus-1, canine herpesvirus and feline herpesvirus-1, all alpha-herpesviruses, cause abortions or neonatal deaths in goats, dogs and cats, respectively. This review discusses the pathogenesis, pathology and laboratory diagnosis of these herpesviral abortions and neonatal diseases, with an emphasis on experimental studies of each disease. Alternative reviews covering other aspects of each infection, such as the genetic and antigenic structure of the viruses, host immune responses and approaches to vaccination and disease control are indicated at appropriate points in the text.

Stabilization of unstable and unintuitive plants by fuzzy control

A heuristically derived stabilization strategy for an unstable and unintuitive plant by fuzzy control is described. It is shown that the often used classical fuzzy controller, which is both static and time invariant, is incapable of stabilizing such types of plants. However, a simple modification to the classical fuzzy controller architecture that separates the measurement and control phases, together with a hierarchical control strategy, enable the unstable and unintuitive plant to be stabilized. The fuzzy control strategy, as well as the new fuzzy controller architecture, are based on the consideration of "what a human subject would do when dealing with a physical plant which is both unstable and unintuitive". The stabilization strategy is then generalized to other mathematically similar systems. While the rules for the stabilization of the plant are heuristically defined, the membership functions associated with the rules are tuned by a simulated annealing procedure.

Mating patterns and reproductive wastage in commercial lowland ewes in west Somerset

The reproductive performance of 5488 ewes in 34 commercially managed, lowland flocks in west Somerset was assessed by means of a questionnaire survey and flock inspections. The introduction of vasectomised rams before the breeding season (teasing) markedly affected the proportions of ewes mated in the first 16 days after the introduction of fertile rams. In teased flocks, 84.7 per cent (range 37.8 to 100 per cent) of the ewes were mated in the first 16 days, compared with 43.8 per cent (range 2.9 to 100 per cent) in unteased flocks (P < 0.0001). Conception rates to first service and the overall percentage of ewes that conceived were similar in the teased and unteased flocks (89.3 per cent vs 92.6 per cent and 99.2 per cent vs 99.4 per cent, respectively). The overall mean (1.59) and range (1.31 to 2.04) litter size, mean (146 per cent) and range (123 to 196 per cent) lambing percentage and mean (94.6 per cent) and range (88.7 to 100 per cent) proportion of live lambs were similar in the teased and unteased flocks. The causes of reproductive failure were anoestrus (0.3 per cent), failure to conceive after multiple matings (0.3 per cent), visible abortion (2.4 per cent) and barren, that is, failing to lamb (3.4 per cent). The total reproductive loss rate was therefore 6.4 per cent of all ewes. Further non-reproductive losses occurred as a result of culling (0.3 per cent) and death during pregnancy (1.5 per cent).

Replication of equid herpesvirus-1 (EHV-1) in the testes and epididymides of ponies and venereal shedding of infectious virus

Six Welsh Mountain pony colts were infected intranasally with the Ab4 isolate of EHV-1. Clinical and virological monitoring demonstrated mild upper respiratory tract disease, with nasal shedding of virus and establishment of a cell-associated viraemia. Detailed pathological examination of the urogenital tract was performed post mortem on days 4-9 post-infection (PI). EHV-1 was isolated from the epididymis on day 8 and the testis on day 9 PI, with viral replication in endothelial cells of these organs and an associated necrotizing vasculitis and thrombosis. Productive viral infection of germinal epithelium was not observed. In a further study, three Welsh Mountain pony stallions were infected intranasally with Ab4, which again resulted in mild upper respiratory tract disease and the establishment of a cell-associated viraemia. Semen samples were collected up to day 60 PI. Two stallions showed a decrease in the proportion of morphologically normal sperm. Significant numbers of inflammatory cells were observed in the sperm-rich fraction of ejaculates collected from one stallion between days 16 and 28 PI; infectious virus was recovered from the semen of this animal between days 17 and 25 PI, after the cessation of viraemia. The affected stallion appeared clinically normal over the period of venereal EHV-1 shedding.

Ovarian fusion in sheep

A survey of ovine reproductive tracts was undertaken in 2 abattoirs in the south west of England, in which 23,536 tracts from nulliparous animals and 9970 tracts from cull ewes were examined. The ovaries were fused in 15 nulliparous animals. In 13 of these animals, 2 ovarian structures could be separately identified macroscopically, whilst in the 2 other animals, a single structure was seen. On histological examination of the ovaries in which 2 structures could be separately identified, the capsules were confluent and formed a septum between them. In the 2 cases with complete ovarian fusion, a narrow connective tissue septum separating the 2 ovaries was present. No cases of ovarian fusion were found amongst the cull ewes, but prominent strands of fibrous tissue connecting the ovaries were present in 2 animals. It is probable that fusion of the ovaries occurs as a developmental abnormality; evidence from the 2 cull ewes suggests that the ovaries separate once oestrous cyclicity has commenced.

Canine lymphomatoid granulomatosis: an immunophenotypic analysis of three cases

Three dogs had a history of multiple progressive lesions affecting the skin, subcutis or skeletal muscles. The lesions developed over a period of several months, and each case demonstrated late cardiopulmonary complications. Post-mortem examination revealed multicentric, angio-destructive, lymphohistiocytic, proliferative lesions typical of the rare disorder lymphomatoid granulomatosis. Immunohistochemical examination demonstrated variable CD3 antigen expression by the atypical cell population in two of the three cases. This provides the first evidence that canine lymphomatoid granulomatosis may be a form of atypical T-cell lymphoma similar to the comparable disorder that occurs in man.

A comparison of equid herpesvirus-1 (EHV-1) vascular lesions in the early versus late pregnant equine uterus

Four Welsh Mountain pony mares at 3 months of gestation and one mare at 5 months were inoculated intranasally with equid herpesvirus-1 (EHV-1: Ab4 isolate) at doses of 10(5) to 10(6.6) TCID50. All five mares became infected, but no cases of paresis or abortion occurred. On days 8, 9, 11, 12 (3-month-pregnant mares) and 13 (5-month-pregnant mare) after infection, a detailed examination of the pregnant uterus was made. Small numbers of vascular lesions with EHV-1 antigen expression in endothelial cells were present in the uteri of the early gestational mares; thrombi were rare and foci of thromboischaemic damage were not seen. Six pony mares previously inoculated with EHV-1 Ab4 at 9 months of gestation had a significantly greater degree of vascular abnormality than that found in the four mares infected at 3 months of gestation, but the degree of EHV-1 antigen expression and thrombosis in the uterus was similar to that found in the single mare infected when 5 months pregnant.

Canine conjunctival papilloma: a review of five cases

Five cases of unilateral bulbar conjunctival papillomata are reported in five different breeds of dog. The dogs ranged from six to nine years of age, four were female and one was male. In all but one case the mass was an incidental finding. The morphology and histopathology are described. The authors have been unable to find any details or descriptions of this type of papilloma in the veterinary literature.

Detection of Mycobacterium tuberculosis in clinical specimens from children using a polymerase chain reaction

OBJECTIVE

We evaluated the usefulness of the polymerase chain reaction (PCR) using the insertion sequence IS6110 as the target for DNA to detect Mycobacterium tuberculosis in clinical specimens from children.

STUDY DESIGN

This was a prospective, controlled, blinded study comparing PCR on clinical specimens, mycobacterial culture, and clinical diagnosis.

PATIENTS

Sixty-five hospitalized children were evaluated, 35 with tuberculosis disease and 30 controls. Cases were defined by culture and/or specific clinical criteria. Controls included patients with tuberculosis infection but no detectable disease as well as patients free of tuberculosis infection and disease.

RESULTS

Polymerase chain reaction had a sensitivity of 40% and a specificity of 80% compared with clinical diagnosis. Mycobacterial culture had a sensitivity of 37%. The combination of culture and PCR identified 19 of 35 children (54%) with clinically diagnosed tuberculosis. There were six children with false-positive PCR results: One had tuberculosis infection without disease, two had Mycobacterium avium lymphadenitis, and three had diagnoses unrelated to tuberculosis.

CONCLUSIONS

The sensitivity of PCR is comparable to that of culture for detecting M tuberculosis in children, and may strengthen and hasten the clinical diagnosis in culture-negative patients. However, because of the limitations in specificity, the results of PCR alone are insufficient to diagnose tuberculosis in children. Although ongoing refinements in PCR techniques should improve the specificity of this test, epidemiologic and clinical information continue to be the most important consideration in the diagnosis of tuberculosis in culture-negative children.