The efficacy of eprinomectin extended-release injection against naturally acquired nematode parasites of cattle, with special regard to inhibited fourth-stage Ostertagia larvae.

The efficacy of eprinomectin in an extended-release injection (ERI) formulation in the treatment of cattle harboring naturally acquired nematode populations (including inhibited nematodes) was evaluated. Five studies were conducted under a similar protocol in the USA, the UK, and in Germany. All study animals were infected by grazing naturally contaminated pastures. The adequacy of pasture infectivity was confirmed by examining tracer calves prior to allocation and treatment of the study animals. The cattle were of various breeds or crosses, weighing 79-491 kg, and aged approximately 6-15 months. In each study, 20 animals were infected by grazing, and then removed from pasture and housed in a manner to preclude further nematode infections for 8-16 days until treatment. Animals were blocked based on descending pre-treatment body weight and randomly allocated to one of two treatments: ERI vehicle (control) at 1 mL/50 kg body weight or eprinomectin 5% (w/v) ERI at 1 mL/50 kg body weight (1.0 mg eprinomectin/kg). Treatments were administered once on Day 0 by subcutaneous injection in front of the shoulder. For parasite recovery and count, all study animals were humanely euthanized 14/15 days after treatment. Cattle treated with eprinomectin ERI had significantly (p<0.05) fewer of the following nematodes than the controls with overall reduction of parasite counts of ≥94%: adult Dictyocaulus viviparus, Capillaria spp., Cooperia oncophora, Cooperia pectinata, Cooperia punctata, Cooperia surnabada, Haemonchus placei, Nematodirus helvetianus, Oesophagostomum radiatum, Ostertagia lyrata, Ostertagia ostertagi, Trichostrongylus axei, Trichostrongylus colubriformis, Trichuris discolor, Trichuris skrjabini, and Trichuris spp.; developing fourth-stage larvae of Ostertagia spp. and Trichostrongylus spp.; and inhibited fourth-stage larvae of Cooperia spp., Haemonchus spp., Nematodirus spp., Oesophagostomum spp., Ostertagia spp., and Trichostrongylus spp. Animal treatments were well accepted, with no adverse reactions to treatment observed in any study animals. The results of this series of controlled studies demonstrated high therapeutic efficacy and acceptability of eprinomectin ERI against pulmonary nematodes and a wide range of gastrointestinal parasitic infections, including inhibited gastrointestinal nematodes, in cattle.

Therapeutic and persistent efficacy of fipronil against Boophilus microplus (Acari: Ixodidae) on cattle.

Cattle infested with all parasitic life-stages of Boophilus microplus (Canestrini) were treated once with a pour-on formulation of fipronil at 0.25, 0.5, or 1.0% active ingredient (AI) to determine the therapeutic efficacy. Additionally, cattle were infested at weekly intervals for 13 consecutive weeks after treatment to determine the persistent effectiveness of the three concentrations. Results of therapeutic efficacy of fipronil showed that with each increase in concentration there was a corresponding and often significant (P < 0.05) decrease in the numbers, fecundity and fertility of engorged females. The overall control of the Index of Reproduction (IR) achieved at 0.25 and 0.5% AI was 86.2 and 94.3%, respectively, while the control of the IR at the 1.0% AI concentration was 99.7%. The persistent efficacy of fipronil, like the therapeutic efficacy, was also dose related. The 0.25% AI treatment failed to provide complete protection (100%) against larval reinfestation, although control of the IR remained high (> 95%) for the first 6 weeks after treatment. In contrast, at 0.5% AI the control of the IR remained at 100% for the first 4 weeks after treatment, and was > 90% for an additional 2 weeks (6 weeks posttreatment). The 1.0% AI concentration afforded the longest residual activity, providing virtually 100% protection against larval reinfestation for 8 weeks after treatment was applied. Based on the results, neither the 0.25 or 0.5% AI concentration completely eliminated the immature stages of the tick (nymphs and larvae) on the host at the time of treatment (therapeutic efficacy), and the residual activity (persistent efficacy) did not prevent reinfestation by larvae for long periods after treatment. While the 1.0% AI concentration provided both therapeutic and residual efficacy that would be suitable for use in the eradication program, caution is still warranted because a few engorged females detached for up to 25 days after treatment, although none reproduced after the 6th day.

Acridine orange staining as a replacement for subculturing of false-positive blood cultures with the BACTEC NR 660.

Despite the customization of growth index thresholds within individual laboratories, use of the BACTEC NR 660 automated blood culture system results in a number of false-positive cultures. The results of Gram staining, acridine orange staining, and subculturing to agar media were evaluated on 210 false-positive blood cultures over a 6-month period. Inclusion of acridine orange staining in the routine workup of false-positive blood cultures can eliminate the need for subculturing.

Residual activity of microencapsulated permethrin against stable flies on lactating dairy cows.

Emulsifiable concentrate and microencapsulated formulations of permethrin were evaluated for residual activity against stable flies on lactating dairy cows. Cows were treated in the field with each formulation and hair was clipped from the leg and shoulder area, and bioassayed at 1, 2, 3, 4, 7 and 14 days after treatment. Significantly more stable flies died when exposed to hair sampled 3, 4 and 7 days after treatment from the shoulder than from the lower leg. Analysis with gas chromatography of hair samples showed no detectable permethrin residues on shoulder or leg hair 72 h after treatment with the emulsifiable concentrate formulation. Microencapsulated permethrin was still detectable on hair sampled from both locations 7 days after treatment. The permethrin concentration on the leg hair was approximately 50% of the shoulder hair concentration after 3 days, with the leg hair residue dropping to 31% of shoulder level after 7 days.

Assessment of ethanol's hedonic effects in mice selectively bred for sensitivity to ethanol-induced hypothermia.

Mice selectively bred for sensitivity (COLD) or insensitivity (HOT) to the hypothermic effect of ethanol were tested in three tasks purported to assess ethanol's hedonic properties: place conditioning, taste conditioning, and ethanol drinking. In the place conditioning task, distinctive tactile (floor) stimuli were differentially paired with injection of ethanol (2.25 g/kg) or saline, and preference for the tactile stimuli was assessed during a choice test without ethanol. In the taste conditioning task, fluid-deprived mice were given repeated access to saccharin followed by injection of ethanol (2.25 g/kg). In the drinking task, mice were given access on alternate days to a single drinking tube containing water or ethanol in a concentration that gradually increased from 1 to 12% (v/v) over days. HOT mice showed greater conditioned preference for ethanol-paired flavor cues, and greater aversion for ethanol-paired flavor cues, and drank less ethanol at concentrations above 5% than COLD mice. HOT mice also showed higher levels of ethanol-stimulated activity than COLD mice. Control experiments indicated that the lines did not differ in initial preference for the tactile and flavor stimuli used in the conditioning tasks. Because the same line differences were seen in mice selected from two genetically independent populations, these studies offer strong evidence of genetic correlations between ethanol's thermal effect and its effect on activity, place conditioning and taste conditioning. Evidence of a genetic correlation between ethanol's thermal effect and ethanol drinking, however, is weaker since it is based on a line difference observed in only one of the genetic replicates. (ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation of human oscillometric blood pressure monitors for use in dogs.

Two digital oscillometric human blood pressure measuring devices were modified and evaluated as blood pressure monitors in 12 healthy anesthetized dogs. Direct arterial pressures were measured via cannulation of the dorsal pedal artery and were correlated with indirect measurements through an inflatable cuff placed over the dorsal pedal artery below the hock joint of the contralateral limb. Direct and indirect measurements were compared for systolic, diastolic, and calculated mean arterial pressures. Blood pressure ranges between 215/145 mm of Hg and 65/30 mm of Hg were obtained, using combinations of halothane, phenylephrine, calcium, and IV administered fluids. Machine A was found to be insufficient for clinical application, on the basis of correlation coefficients between direct and indirect pressures of 0.78, 0.65, and 0.74 for systolic, diastolic, and mean arterial pressures, respectively. Higher correlation coefficients between direct and indirect pressures (0.77, 0.87, and 0.87, respectively) were obtained with machine B. The results of the study reported here suggest machine B may be an effective blood pressure monitoring device in anesthetized dogs.

Similarities and differences of care in a medical center.

Explicates a medical-pastoral paradigm in terms of eight "polar unities": natural science/theology; person/organism; efficient/teleodogical causality; multivocal/univocal language; quantitative/qualitative concerns; meaning/technical interventions; description/value; validation of intervention effectiveness. Suggests that these varieties of approaches may be illustrated in the ancient Oriental Yin-Yang symbol which includes the kind of "polar unity" implicit in a modern medical center.

Comparison of the catalytic oxidation of cysteine and o-dianisidine by cupric ion and ceruloplasmin.

Several features of the catalytic oxidation of cysteine by ceruloplasmin and nonenzymic Cu(II) at pH 7 have been compared. The oxidation of cysteine by ceruloplasmin has several properties in common with the Cu(II) catalyzed oxidation of cysteine: pH maxima, thiol specificity, lack of inhibition by anions, and high sensitivity to inhibition by copper complexing reagents. These two catalysts differed in their molecular activity, in their ability to oxidize penicillamine and thioglycolate, and in that H2O2 was produced as a primary product only during Cu(II) oxidation. The oxidation of cysteine by ceruloplasmin was compared also with the ceruloplasmin catalyzed oxidation of o-dianisidine, a classical pH 5.5 substrate. The mechanism of the oxidation of cysteine by ceruloplasmin at pH 7 differed from that of o-dianisidine oxidation because the latter substrate was inhibited by anions but not by copper complexing agents. Spectral and other data suggest that during the ceruloplasmin reaction with cysteine there is a one electron transfer from cysteine to ceruloplasmin resulting in the specific reduction of type 1b Cu(II).

The national system of scientific measurement.

Mandated measurement methods are required by regulatory agencies and other government groups. These methods exist for measuring almost all physical, chemical, and biological phenomena. The methods have been culled from the literature, from the organizations that write voluntary standards, and some have been developed by the agencies. Few provide adequate estimates of precision, and fewer still provide any evaluation of interlaboratory bias. The societal costs of these poor measurements are large. Much needs to be done to meet the physical and statistical requirements for establishing and maintaining dependable measurements. Excepting those directly supported by the National Bureau of Standards, most of the nation's measurement systems are uncontrolled.

Genetic characterization of the metK locus in Escherichia coli K-12.

Three independently isolated metK mutants have been shown to have leisions lying between speB and glc near 57 min on the Escherichia coli chromosome. Two deletions result in a lack of the metC gene product but neither extends into the metK glc region. The three metK mutations are recessive to the wild-type allele carried on the KLF16 episome.

Properties of metK mutants of Escherichia coli K-12.

Some of the properties of three metK mutants of Escherichia coli K-12 have been examined. All three strains have lower than normal levels of SAM (S-adenosyl-l-methionine) synthetase and elevated levels of cystathionine synthetase and cystathionase. One strain (RG73) appears to have an unstable SAM synthetase, suggesting that it carries a structural gene mutation. The two strains (RG62 and RG109) which have the lowest levels of SAM synthetase when grown on minimal medium have appreciably higher levels of enzyme when grown on complete medium. Growth on defined media supplemented with leucine or methionine causes a several-fold increase in the specific activity of SAM synthetase with associated decreases in cystathionine synthetase and cystathionase, but the changes are not as large as those seen in cells grown on LB broth. The SAM pools of strains RG62 and RG109 are markedly lower than normal while that of strain RG73 is slightly below normal. The methionine pools of all three strains are elevated several-fold. The metK strains are able to synthesize cyclopropane fatty acids, but the rate of their formation is slowed. Modification and restriction of phage 21 appears to be normal, suggesting that these strains are able to methylate DNA.