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.

A pathological study of a mycobacterial infection in a cat caused by a variant with cultural characteristics between Mycobacterium tuberculosis and M bovis

A histological examination of a biopsy from a firm submandibular mass in a seven-year-old domestic short-haired cat revealed a granulomatous lymphadenitis associated with the presence of small numbers of acid-fast bacilli. The cat was euthanased and subjected to a detailed post mortem examination which revealed extensive granulomatous inflammation in the right and left bronchial, para-aortic, mesenteric and colic lymph nodes, with small or early lesions in the lung and Peyer's patches of the ileum. Mycobacteria were isolated from the submandibular, mesenteric and cervical lymph nodes. The bacilli reacted with a DNA probe specific for the tuberculosis complex, including Mycobacterium tuberculosis and M bovis, but had cultural characteristics intermediate between these two species. The pathological findings are compared with previous reports of mycobacterial infections in cats, and the public health implications are discussed.

A decision-supported outpatient practice system

We describe a Decision-supported Outpatient Practice (DOP) system developed and now in use at the Columbia-Presbyterian Medical Center. DOP is an automated ambulatory medical record system that integrates in-patient and ambulatory care data, and incorporates active and passive decision support mechanisms with a view towards improving the quality of primary care. Active decision support occurs in the form of event-driven reminders created within a remote clinical information system with its central data repository and decision support system (DSS). Novel features of DOP include patient specific health maintenance task lists calculated by the remote DSS. uses of a semantically structured controlled medical vocabulary to support clinical results review and provider data entry, and exploitation of an underlying ambulatory data model that provides for an explicit record of evolution of insight regarding patient management. Benefits, challenges, and plans are discussed.

Congenital abnormalities of the ovine paramesonephric ducts

A 15 month survey of ovine reproductive tracts was undertaken in slaughterhouses in southwest England. A total of 33506 tracts were examined; 23536 from lambs and 9970 from adults. In total, 3.4% of tracts were pregnant and 3.3% exhibited abnormalities. Twenty cases of uterus unicornis, six of uterus didelphys and 11 of segmental aplasia were encountered, such that partial aplasia of the paramesonephric ducts accounted for 3.3% of all abnormalities. Although developmental abnormalities of the ovine female genital system are relatively uncommon, a substantial proportion of these can be accounted for by development defects of the paramesonephric ducts.

Replication of equid herpesvirus 4 in endothelial cells and synovia of a field case of viral pneumonia and synovitis in a foal

Equid herpesvirus 4 (EHV-4) infection was diagnosed as the cause of interstitial pneumonia in a 6-week-old conventionally reared Welsh pony foal, by cocultivation and immunolabelling with specific monoclonal antibodies, EHV-4 specific amplification of viral DNA, and immunohistological examination of infected tissues. The case was novel in that replication of the EHV-4 isolate in endothelial cells and in the synovial epithelium was a feature. Restriction digests of this isolate were compared with those of seven respiratory and one abortigenic EHV-4 isolate, and no differences in restriction pattern were evident. The implications of these findings for the pathogenesis of EHV-4 infection are discussed.

Equine strangles modelled in mice

Small animal models of Streptococcus equi infection have been confined to parenteral injection of mice which subsequently develop a septicaemia. To devise a model of infection more closely resembling strangles, 4.9 x 10(6) cfu of S. equi were placed on the nares of C3H and Balb/c mice (fifteen of each). Compared with ten uninfected controls, infected mice sneezed more often and their daily weight gain was significantly reduced. Histopathological examination seven days after infection revealed varying degrees of nasopharyngeal and regional lymphoid pathology in twenty two mice. Eleven mice had an early or mild rhinitis in which the nasal epithelium presented microabscesses containing polymorphonuclear leucocytes. Another eleven mice had a suppurative rhinitis or pharyngitis associated in most with regional lymphadenitis; in two mice, abscessated lymph nodes had erupted into perinodal connective tissues. Two mice had a vestibular abscess. The suppurative rhinitis was associated with extensive necrosis of nasal propria which occasionally extended to conchal bone, resulting in osteomyelitis. Multiple bacterial abscesses were seen in the spleen of one mouse. Histological lesions were not detected in control mice or in eight infected mice. S. equi was re-isolated from the nares of fourteen of the twenty two affected mice but not from the eight unaffected challenged mice or control mice. The close resemblance of this model to strangles in horses may justify its further use for the investigation of pathogenesis and protective immunity.

DNA sequence analysis of spontaneous and gamma-radiation (anoxic)-induced lacId mutations in Escherichia coli umuC122::Tn5: differential requirement for umuC at G.C vs. A.T sites and for the production of transversions vs. transitions

Escherichia coli umuC122::Tn5 cells were gamma-irradiated (137Cs, 750 Gy, under N2), and lac-constitutive mutants were produced at 36% of the wild-type level (the umuC strain was not deficient in spontaneous mutagenesis, and the mutational spectrum determined by sequencing 263 spontaneous lacId mutations was very similar to that for the wild-type strain). The specific nature of the umuC strain's partial radiation mutability was determined by sequencing 325 radiation-induced lacId mutations. The yields of radiation-induced mutation classes in the umuC strain (as a percentage of the wild-type yield) were: 80% for A.T-->G.C transitions, 70% for multi-base additions, 60% for single-base deletions, 53% for A.T-->C.G transversions, 36% for G.C-->A.T transitions, 25% for multi-base deletions, 21% for A.T-->T.A transversions, 11% for G.C-->C.G transversions, 9% for G.C-->T.A transversions, and 0% for multiple mutations. Based on these deficiencies and other factors, it is concluded that the umuC strain is near-normal for A.T-->G.C. transitions, single-base deletions and possibly A.T-->C.G transversions; is generally deficient for mutagenesis at G.C sites and for transversions, and is grossly deficient in multiple mutations. Damage at G.C sites seems more difficult for translesion DNA synthesis to bypass than damage at A.T sites, and especially when trying to produce a transversion. The yield of G.C-->A.T transitions in the umuC strain (36% of the wild-type level) argues that abasic sites are involved in no more than 64% of gamma-radiation-induced base substitutions in the wild-type strain. Altogether, these data suggest that the UmuC and UmuD' proteins facilitate, rather than being absolutely required for, translesion DNA synthesis; with the degree of facilitation being dependent both on the nature of the noncoding DNA damage, i.e., at G.C vs. A.T sites, and on the nature of the misincorporated base, i.e., whether it induces transversions or transitions.

Distribution of equid herpesvirus-1 (EHV-1) in the respiratory tract of ponies: implications for vaccination strategies

Twelve adult ponies and 2 conventional foals were exposed to 10(6.6) TCID50 of Equid herpesvirus-1 (EHV-1), strain Ab4 and samples of respiratory tract tissues were recovered. Infectious virus in tissue homogenates was detected using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry of paraffin sections. The results illustrated the rapid dissemination of EHV-1 throughout the respiratory tract, with early replication in the lungs one day after exposure. Endothelial cell infection was prominent in all areas of the nasopharynx by Day 4 emphasising the role of endotheliotropism and viraemia in dissemination of this virus to sites of secondary replication. Clinical disease in the adult ponies was mild.

Distribution of equid herpesvirus-1 (EHV-1) in respiratory tract associated lymphoid tissue: implications for cellular immunity

Twelve adult ponies and 2 conventional foals were exposed intranasally to EHV-1, strain Ab4 (TCID50 10(-6.6) and samples of respiratory tract associated lymphoid tissues were recovered between 12 h and 13 days after infection. Infectious virus was detected in tissue homogenates using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry on paraffin sections. The results showed both infectious EHV-1 and viral antigens in respiratory tract associated lymph nodes 12 h after exposure. Infected leucocytes were identified morphologically as lymphocytes, monocytes, macrophages and plasma cells. The rapid intracellular localisation of EHV-1 in lymph nodes implies that cell mediated immunity is an important aspect of the equine response to this virus.

DNA sequence analysis of gamma-radiation (anoxic)-induced and spontaneous lacId mutations in Escherichia coli K-12

An extensive spectrum of ionizing radiation mutagenesis was determined by sequencing 318 137Cs gamma-radiation (anoxic)-induced episomal lacId mutations in Escherichia coli strain NR9102. The most commonly found radiation-induced mutations were base substitutions (44% transversions and 41% transitions). The radiation-induced spectrum consisted of: 23% G.C-->A.T, 18% A.T-->G.C, 17% G.C-->T.A, 14% G.C-->C.G, 8% A.T-->T.A, 6% A.T-->C.G, 8% single-base deletions, 5% multiple mutations, 3% multi-base deletions, and essentially no single- or multi-base additions. This spectrum compared better with spectra for other systems obtained by in vivo irradiation than with one obtained by in vitro irradiation. Multiple mutations, which were unique to the radiation-induced spectrum, generally consisted of one active and one closely linked silent mutation, and are suggested to result from an altered replication complex of reduced fidelity. Mutation rates were 4.1 x 10(-8) lac-constitutive mutations/gene/Gy and 1.2 x 10(-10) base substitutions/base pair/Gy. Thirty-two percent more radiation-induced mutations occurred at G.C vs. A.T base pairs. A strand asymmetry was noted for G.C-->C.G and A.T-->T.A transversions. A nearest-neighbor analysis showed that C (vs. A, G, or T), on either side of the mutation site, substantially enhanced most types of base substitutions. Similarly, G and C flanked both sides of single-base deletion sites twice as frequently as would be expected from the base composition of the mutation target. For comparative purposes, we sequenced 411 spontaneous lac-constitutive mutants of which 269 were lacId mutants, and there was good agreement between these and previously published mutational spectra. The spontaneous and radiation-induced mutational spectra differed substantially for virtually every class of mutation. For example, the set of spontaneous dominant lac-constitutive mutations contained many more mutations that did not map in the normal region for lacId mutations (i.e., 35% vs. 3%) and were presumed to be lacO-constitutive mutations. A sampling of these presumptive lacOc mutations was also sequenced: 17/22 (spontaneous) and 1/9 (radiation) were found to be lacOc long deletions, one from each set were base substitutions, and the remaining mutations showed the wild-type lacO sequence. Like the radiation-induced spectrum, the spontaneous spectrum showed enhanced mutagenesis at G.C sites, strand asymmetry, and enhanced mutagenesis when G or C were the nearest neighbors.

Evaluation of the conformational free energies of loops in proteins

In this paper we discuss the problem of including solvation free energies in evaluating the relative stabilities of loops in proteins. A conformational search based on a gas-phase potential function is used to generate a large number of trial conformations. As has been found previously, the energy minimization step in this process tends to pack charged and polar side chains against the protein surface, resulting in conformations which are unstable in the aqueous phase. Various solvation models can easily identify such structures. In order to provide a more severe test of solvation models, gas-phase conformations were generated in which side chains were kept extended so as to maximize their interaction with the solvent. The free energies of these conformations were compared to that calculated for the crystal structure in three loops of the protein E. coli RNase H, with lengths of 7, 8, and 9 residues. Free energies were evaluated with a finite difference Poisson-Boltzmann (FDPB) calculation for electrostatics and a surface area-based term for nonpolar contributions. These were added to a gas-phase potential function. A free energy function based on atomic solvation parameters was also tested. Both functions were quite successful in selecting, based on a free energy criterion, conformations quite close to the crystal structure for two of the three loops. For one loop, which is involved in crystal contacts, conformations that are quite different from the crystal structure were also selected. A method to avoid precision problems associated with using the FDPB method to evaluate conformational free energies in proteins is described.

The identification of 5-hydroxy-L-norvaline in cultures of pyridoxine auxotrophs of Escherichia coli B

Gc-ms and hplc have been employed to identify 5-hydroxy-L-norvaline (L-2-amino-5-hydroxypentanoic acid) in the culture fluids of pyridoxine-starved cultures of two pyridoxine auxotrophs of Escherichia coli B. The production of 5-hydroxynorvaline is shown to be secondary to pyridoxine starvation of the cultures, and the quantities of 5-hydroxynorvaline are similar to those of the common protein amino acids present in these cultures. This is the first time that 5-hydroxynorvaline has been identified as a product of bacterial metabolism.

Nutrient effects on growth and the production of 5-hydroxy-4-oxonorvaline by Streptomyces akiyoshiensis

5-Hydroxy-4-oxonorvaline (HON) was produced optimally by Streptomyces akiyoshiensis in media containing starch and casein supplemented with high concentrations of phosphate and magnesium sulfate; cultures grown at initial pH values between 6.3 and 6.6 yielded HON titres of 13-14 mM. Physiological analysis of HON production provided evidence that the excess inorganic constituents in this medium played an important role in optimizing production. In simple defined media buffered at pH 5.5-6.0 and inoculated with either a spore suspension or washed vegetative mycelium, formation of HON was less than one-third the amount produced in the starch-casein-salts medium. Production was markedly affected by the carbon and nitrogen sources used; media containing starch and potassium nitrate or aspartate supported the highest yields of HON. In starch-nitrate media, production was suppressed by excess nitrogen source, and the HON titre decreased 3-fold as the phosphate content was increased from 0.5 to 5 mM; growth was not appreciably altered. The results suggest that the high level of HON production in the complex starch-casein-salts medium is associated with sequestration of metabolic ammonium and reduced availability of phosphate through formation of the poorly soluble magnesium ammonium phosphate.

Replication of equid herpesvirus-1 in the vaginal tunics of colts following local inoculation

Equid herpesvirus-1 (EHV-1; Ab4 isolate) was inoculated unilaterally into the cavum vaginale of four pony colts under general anaesthesia. The animals were monitored daily for evidence of scrotal or testicular swelling and euthanased electively on days 3, 4, 6 and 12 after infection. Detailed pathological examination of the male genital tract was carried out. In animals examined at days 3 and 4 after infection, replication of EHV-1 was detected bilaterally in mesothelial and endothelial cells of the parietal and visceral vaginal tunics. The mesothelial infection had resolved by day 12 after infection, with no evidence of direct extension to deeper genital organs. None of the four colts showed significant scrotal or testicular swelling.