A panel of horse-mouse heterohybridoma cells was tested for genetic markers using biochemical and polymerase chain reaction-(PCR-) based tests. Biochemical markers included phosphoglucomutase (PGM), glucose phosphate isomerase (GPI) and 6-phosphogluconate dehydrogenase (PGD). Markers detected using PCR-based tests included microsatellite markers HTG2-15, HMS 1-3, 5-8, VHL20, ECA2 and genes for equine major histocompatibility gene ELA-DRA, tumour necrosis factor alpha (TNFA) and transferrin. The results were analysed for correlation and concordance. Based on the results, five synteny groups were identified, specifically between ELA-DRA, TNFA, HMS5 and HTG5; between HTG3 and HTG13; between HTG4, HTG8 and HMS3; between HTG6 and HMS1; and between HTG7, HTG9 and HMS6. Evidence was also found for synteny between HTG12, HMS7 and ECA2, however, confirmation requires further testing. Cytogenetic evaluation of the cell lines making up the panel indicated that large metacentric chromosomes were preferentially lost or tended to break at the centromere. Consequently, the results from this analysis can be used to identify synteny, but not to exclude synteny.

Animals↗

PubMed1995

Genetics and disease in the horse.

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Animals↗

PubMed1995

A positive, individually ventilated caging system: a local barrier system to protect both animals and personnel.

Most local barrier systems are designed primarily either to protect animals from airborne contamination (exclusion) or to ensure the safety of personnel (hazard containment). Few, other than isolators, are able to cope with the often conflicting demands to do both. The Positive Individually Ventilated system (PIV), which provides pressure adjustable, individual supply and exhaust ventilation to each cage has been tested with this in mind as well as the need to ensure that environmental conditions comply with the requirements of the Home Office Code of Practice (CoP). The results indicate that when compared with traditional open racking the system can reduce both the risk of animals becoming contaminated by airborne infection from the room and the risk of aeroallergens escaping from the cages into the room air. At the same time, environmental conditions within the cages are both less variable and less stressful to the occupants. Conditions of air temperature, relative humidity, ventilation rates, light intensity and (with appropriate air handling) sound levels, all comply with or are better than those required by the CoP. Even with the room air change rate set at only 8/h (8 ac/h) the air distribution system results in draught-free cage ventilation rates of around 50-120 ac/h. This means that with at least the PIV exhaust(s) linked directly into the air conditioning system of the building, the size of the latter and its associated running costs can be reduced by around 50%; this energy saving concept has been approved in principle by the Home Office. Additional benefits include the fact that bedding is kept much drier allowing further cost savings in bedding and associated labour costs. The system is thus beneficial to the animals in protecting them from airborne infection and other stresses. By providing a less variable environment it also helps to minimise the sort of interference with experiments which can arise from that source. Similarly, in accordance with the aims of 'The Control of Substances Hazardous to Health Regulations' (COSHH 1988) and the Health & Safety Executive (HSE 1990), by reducing dust levels in the room air, including allergens, it is also beneficial to the personnel working in the animal rooms.

Air Pollutants, Occupational↗

PubMed1994

Transplacental exposure to genotoxins. Evaluation in haemoglobin of hydroxyethylvaline adduct levels in smoking and non-smoking mothers and their newborns.

The N-(2-hydroxyethyl)valine (HOEtVal) adduct resulting from the interaction of ethylene oxide with the N-terminal valine in haemoglobin, was determined in blood samples taken from non-smoking pregnant women (n = 10) and from pregnant women (n = 13) smoking 15 or more cigarettes a day. The HOEtVal levels were also determined in the haemoglobin from blood samples taken, within 48 h of delivery, from the newborns of these mothers. In the maternal haemoglobins, the average HOEtVal adduct level was increased from a background of 63 +/- 20 (mean +/- SD) pmol/g globin in the non-smoking mothers to 361 +/- 107 (mean +/- SD) pmol/g globin in the smoking mothers. Haemoglobin adducts were also detected in all the babies' blood samples. The concentrations in the newborns from smoking mothers [147 +/- 68 (mean +/- SD) pmol/g globin] was significantly higher (P < 0.01) than the concentrations in the newborns from non-smoking mothers [42 +/- 18 (mean +/- SD) pmol/g globin]. A significant correlation (P < 0.01) was found between newborns and maternal HOEtVal adduct levels.

Carcinogens↗

PubMed1994

Comparison of thoroughbred and Arabian horses using RAPD markers.

We compared pools of DNA from 10 Thoroughbred horses and 10 Arabian horses for the presence of randomly amplified polymorphic DNA (RAPD) markers which might be useful in distinguishing between the breeds. Using 212 decamer oligonucleotides and our polymerase chain reaction (PCR) conditions, 173 of the primers produced scoreable bands. The number of bands ranged from 0 to 9 with an average of 3.6. In family studies using 11 arbitrarily selected primers, five of the 11 primers produced polymorphic bands which exhibited Mendelian inheritance as dominant markers. When comparing the pooled DNA from Thoroughbred and Arabian horses we found 10 primers which identified markers present in the pooled DNA from one breed but absent in the pool from the other breed. Testing individual horses revealed that only two markers were wholly absent for one group while being present among members of the other. Primer UBC-85 (5'-GTGCTCGTGC-3') detected a pair of markers absent in Thoroughbred horses but present among 11 of 31 Arabian horses. These markers were 1500 and 1700 base pairs (bp) long and designated UBC-85C and UBC-85D, respectively. Primer UBC-126 (5'-CTTTCGTGCT-3') detected a 1000 bp marker (designated UBC-126C) absent in 20 of 20 Thoroughbred horses but present in 31 of 31 Arabian horses.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

Antifungal prophylaxis with low-dose fluconazole during bone marrow transplantation. The Bone Marrow Transplantation Team.

The present study investigated the prophylactic efficacy of fluconazole at 100-200 mg/day against invasive fungal infections during bone marrow transplantation (BMT). During July 1990 to December 1991, all BMT recipients received antifungal prophylaxis with fluconazole at either 200 mg/day or 100 mg/day. Historical controls were those that received no antifungal prophylaxis (January 1989 to June 1990). Fungemia occurred in 4 of 112 fluconazole recipients and 8 of 79 controls (p < 0.05) prior to engraftment. Torulopsis (Candida) glabrata (three patients), Cryptococcus terreus and Candida tropicalis (mixed in one patient) caused fungemia in four patients in the fluconazole group; Candida albicans caused six of eight fungemic episodes in the controls. All three Torulopsis glabrata isolates were fluconazole-resistant. Colonization due to C. albicans was markedly diminished in the fluconazole group (19 of 112 patients versus 53 of 79 controls). T. glabrata, on the other hand, was a more common colonizing organism in the fluconazole group (36 of 112 vs 10 of 79). The frequency of isolating C. albicans and/or T. glabrata was significantly different between fluconazole and control groups (p < 0.0001). Empiric use of amphotericin B therapy was markedly reduced in the fluconazole group (4.5% vs 34%; p < 0.0001). Fluconazole at 200 mg/day or 100 mg/day appeared equally effective. Fluconazole at a daily dose of 100 mg or 200 mg as antifungal prophylaxis during BMT: (1) significantly reduced the frequency of systemic fungal infections, (2) markedly reduced colonization and infection due to C. albicans, and (3) markedly reduced the need for empiric amphotericin B therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Linkage studies between the Tcp-1, Tcp-10, and Mhc-Eqca-A loci in the horse.

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Animals↗

PubMed1993

Monitoring of exposure to styrene oxide by GC-MS analysis of phenylhydroxyethyl esters in hemoglobin.

Styrene oxide, which is the genotoxically active metabolite of styrene, reacts in vivo with carboxylic acid residues in hemoglobin forming phenylhydroxyethyl esters. Mild alkali hydrolysis cleaves these ester adducts, yielding styrene glycol, which in human blood labelled in vitro with 14C-styrene oxide accounted for 15% of the total radioactivity covalently bound to the protein. A quantitative assay procedure has been developed for measuring the base released styrene glycol in globin. The method utilizes solvent extraction followed by trimethylsilyl ether derivatization and separation and quantitation by capillary gas chromatography with selective ion recording mass spectrometry. Globin labelled in vitro with d8-styrene oxide was used as the internal standard. The method was used to establish a dose-response relationship in rats given single i.p. doses of styrene oxide (83.3-833 mumol/kg body wt). The method, which allows quantitation of the adducts down to levels of 15 pmol/g globin, has the potential to act as a dosimeter for industrial workers exposed to styrene or styrene oxide.

Animals↗

PubMed1993

DNA sequence analysis of serologically detected ELA class II haplotypes at the equine DQ beta locus.

The genetic diversity at the ELA DQ beta locus was investigated using polymerase chain reaction and DNA sequencing. Based upon serological methods 16 class II homozygous animals were selected and their genomic DNA was used. A DQ beta gene from an equine cDNA library was also sequenced. Our methodology and the similarity between the genomic and the cDNA sequences suggest that the studied locus is expressed on equine lymphocytes. In the predicted amino acid sequence the most extensive variation is located at residues 56-60. The pattern of these five amino acids is strongly correlated to the serological ELA class II specificities (W13, W22, W23, Be200). The alleles corresponding to the W23 specificity are the most divergent among the equine DQ beta alleles and also from other mammalian DQ beta sequences.

Alleles↗

PubMed1993

Monitoring exposure to 4,4'-methylene-bis(2-chloroaniline) through the gas chromatography-mass spectrometry measurement of adducts to hemoglobin.

4,4'-Methylene-bis(2-chloroaniline) (MOCA) is widely used as a curing agent in the plastics industry. The determination of the covalently bound reaction products to hemoglobin (Hb) has been investigated as a biomonitoring method for occupational exposure to this potential human carcinogen. Initial studies using the 14C-ring-labeled MOCA showed that 24 hr after a single IP dosage to rats (3.74 mumole/kg), 0.08% of the administered dose was adducted to the Hb, and base hydrolysis liberated 38% of the bound radioactivity. The only product released on hydrolysis was the parent diamine. A specific and sensitive assay procedure using capillary gas chromatography-mass spectrometry has been developed for determining the base-released MOCA adduct down to levels of 20 pmole/g Hb. This method has been used to establish a linear dose-response relationship in IP dosed rats between production of the adduct and dose of MOCA (3.74-44.94 mumole/kg). It is proposed to use analysis of the Hb adduct as a dosimeter for industrial workers exposed to MOCA.

Animals↗

PubMed1993

Identification of endogenous electrophiles by means of mass spectrometric determination of protein and DNA adducts.

Monitoring exposure to alkylating agents may be achieved by quantitatively determining the adduct levels formed with nucleic acids and/or proteins. One of the most significant results arising from the application of this approach has been the discovery in control populations of "background" levels of alkylated nucleic acid bases or alkylated proteins, in particular hemoglobin (Hb). In the case of Hb, a wide variety of such adducts have been detected and quantitated by mass spectrometric techniques, with methylated, 2-carboxyethylated, and 2-hydroxyethylated modifications being most abundant. Although the source of these alkylation products is unknown, both endogenous and exogenous sources may be proposed. We have recently confirmed the presence of the N-terminal hydroxyethylvaline adduct in control human Hb using tandem mass spectrometry (MS-MS) and have now established background levels using GC-MS in more than 70 samples. Smoking raises the levels of the adduct up to 10-fold and occupational exposure to ethylene oxide up to 300-fold. Background levels of alkylated nucleic acids may be studied by analysis of N7-alkylated guanine or N3-alkylated adenine, which are excised from nucleic acids after their formation and are excreted in urine. Although the presence of some of these urinary constituents may be accounted for by their natural occurrence in RNA or diet, the endogenous or exogenous source of others is unknown. Quantitative methods using MS-MS have now been developed for five of the observed urinary alkylguanines [N7-methyl-, N2-methyl-, N2-dimethyl-, N7-(2-hydroxyethyl)-, and N2-ethylguanine].(ABSTRACT TRUNCATED AT 250 WORDS)

Alkylating Agents↗

PubMed1992

Acetoxime is metabolized by human and rodent hepatic cytochrome P450 enzymes to the genotoxicant and carcinogen propane 2-nitronate.

The hepatocarcinogenicity of acetoxime has been tentatively linked with its metabolic oxidation to the potent genotoxicant and carcinogen propane 2-nitronate (P2-N). In order to test the hypothesis that acetoxime is metabolized to P2-N, the oxime (20 mM) was incubated with liver microsomes from mice, rats and two humans. Ion-pair HPLC analysis of the incubates afforded a peak that co-eluted with P2-N. P2-N exists in tautomeric equilibrium with 2-nitropropane (2-NP). Samples of the microsomal incubates, which had been adjusted to pH 5.5 and kept for 24 h in order to allow maximal tautomeric equilibration of P2-N to 2-NP to occur, were extracted with hexane. GLC analysis of the extracts yielded a peak that co-eluted with 2-NP, and gave a mass spectrum identical to that of authentic 2-NP. The metabolite peak obtained on HPLC was isolated and its hexane extract contained also 2-NP when investigated by GLC. P2-N was found by HPLC in the urine of rats that had received acetoxime (3.36 mmol/kg i.p.). Hexane extracts of urine samples, which had been adjusted to pH 5.5 and left for 24 h, contained 2-NP as demonstrated by GLC analysis. The results are consistent with the suggestion that the toxicity of acetoxime is associated with its biotransformation to P2-N.

Animals↗

PubMed1992

Office endoscopy.

Increasing numbers of physicians are considering office endoscopy. Planning for office endoscopy should include the nursing personnel who will be staffing the unit. This article introduces readers to office endoscopy and addresses issues involved in establishing an office-based endoscopy center.

Endoscopes↗

PubMed1992

Hormonal induction of malic enzyme in rat hepatocytes cultured on laminin-rich gels.

The levels of malic-enzyme mRNA and activity were determined in primary cultures of adult rat hepatocytes maintained on either rat-tail collagen or a laminin-rich substratum. Cells plated on laminin-rich gels exhibited substantially improved patterns of albumin and malic-enzyme expression when compared with cells maintained on rat-tail collagen. Moreover, hepatocytes plated on the laminin-rich matrix displayed marked malic-enzyme inducibility in response to tri-iodothyronine and dichloroacetate, especially in the presence of insulin. However, Northern blot analysis revealed that the ratio of the amounts of the two major malic-enzyme mRNA species (2.0 and 3.1 kb) was reversed when compared with that found in the liver in vivo, the altered levels of these two species being closer to those found in non-hepatic tissues. These findings indicate that, although the hormonal responsiveness of isolated hepatocytes maintained on laminin-rich gels is markedly improved, and approaches the degree of induction demonstrated in the liver in vivo, the mechanisms of control differ, indicating a loss of liver-specific expression.

Animals↗