Prevalence of the Campylobacter multi-drug efflux pump (CmeABC) in Campylobacter spp. Isolated from freshly processed Turkeys

The prevalence of the Campylobacter multi-drug efflux pump (CmeABC) was evaluated in Campylobacter isolates recovered from freshly processed turkeys at two Midwestern processing plants. A total of 94 Campylobacter isolates recovered from processed turkeys were examined using polymerase chain reaction (PCR) to determine the presence of the multi-drug efflux pump genes cmeA, cmeB, and cmeC. Results from this study found that 51% of all isolates tested were positive for CmeABC. 46.6% of these positive isolates were from plant A and 55.1% from plant B. Differences were observed in the prevalence of individual genes found among Campylobacter isolates from each plant. Additional analysis found that among the isolates positive for CmeABC, 85.5% were identified as C. jejuni and 14.5% identified as C. coli. There was a relatively high occurrence of the Campylobacter multi-drug efflux pump genes in Campylobacter spp. recovered from processed turkeys, however, the presence of the genes could not be significantly linked to antimicrobial resistance observed in the test strains and suggests that the CmeABC genes are only one factor associated with antimicrobial resistance in Campylobacter spp.     

Interrelationships of several process-reactive measures.

94 schizophrenic patients served as Ss. 8 previously used and potential process-reactive measures were intercorrelated and factored by the principal-factor solution. 2 factors were rotated. The 1st factor, consisting of marital status and the Philips, Elgin, and Ullmann-Giovannoni scales, consisted of traditional process-reactive measures. The variables making up the 2nd factor do not appear to be appropriate process-reactive indices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Bovine Staphylococcus aureus mastitis: strain recognition and dynamics of infection.

Restriction enzyme fragmentation pattern (REFP) analysis was used to recognise Staphylococcus aureus strain variation in naturally occurring bovine subclinical mastitis. Multiple colony REFP analysis identified eight distinct strains of S. aureus in addition to the original strains A and B that were infused via the intramammary route, indicating that individual quarters of the udder may be colonised simultaneously by more than one strain of S. aureus. Examination of multiple colonies per milk sample may benefit bacterial strain recognition as an epidemiological tool in mastitis investigations. The dynamics of intramammary infection were determined using a novel double crossover experimental challenge. Quarters remained persistently infected for several weeks following challenge in all four cows, irrespective of the challenge strain. This indicated that no alteration of the original subclinical infection, including the possible induction of clearance of the quarters infected with S. aureus, or replacement of the original strain by the infused strain was induced by challenge. The persistent subclinical infection in all four animals supports previous reports on the chronicity of S. aureus intramammary infection in dairy cows.     

2-Fluoro-4-pyridinylmethyl analogues of linopirdine as orally active acetylcholine release-enhancing agents with good efficacy and duration of action

In an effort to improve the pharmacokinetic and pharmacodynamic properties of the cognition-enhancer linopirdine (DuP 996), a number of core structure analogues were prepared in which the 4-pyridyl pendant group was systematically replaced with 2-fluoro-4-pyridyl. This strategy resulted in the discovery of several compounds with improved activity in acetylcholine (ACh) release-enhancing assays, in vitro and in vivo. The most effective compound resulting from these studies, 10, 10-bis[(2-fluoro-4-pyridinyl)methyl]-9(10H)-anthracenone (9), is between 10 and 20 times more potent than linopirdine in increasing extracellular hippocampal ACh levels in the rat with a minimum effective dose of 1 mg/kg. In addition to superior potency, 9 possesses an improved pharmacokinetic profile compared to that of linopirdine. The half-life of 9 (2 h) in rats is 4-fold greater than that of linopirdine (0.5 h), and it showed a 6-fold improvement in brain-plasma distribution over linopirdine. On the basis of its pharmacologic, pharmacokinetic, absorption, and distribution properties, 9 (DMP543) has been advanced for clinical evaluation as a potential palliative therapeutic for treatment of Alzheimer's disease.     

Claw lesions in dairy cattle: development of sole and white line haemorrhages during the first lactation

To assess the role of genetic changes in sensitivity to leptin hormone in contributing to responses to long-term selection for fatness, leptin was administered to a long-term fat selected (F) and a control line (C) of mice. These lines differ almost three fold in their percentage of fat (fat%) at about 15 weeks of age. Treated (T) animals received twice-daily intraperitoneal injections of 5mg/kg leptin from 91 to 105 days of age; untreated (U) animals received equivolume injections of phosphate-buffered saline. Treated compared with untreated animals in both lines had significantly (P < 0.05) lower mean body weight, food intake and fatness at the end of test (fat%: CT 3%, CU 7.4%, FT 14.9%, FU 21.1%). The differences in response between the lines [(CT-CU)-(FT-FU)] were all non-significant (P > 0.05), however. There was a very wide range of fatness (estimated from dry matter content) among FT animals (3-29%), much higher than in FU (15-31%), CT (0.7-6.4%) and CU (2-15%) animals. While sensitivity to leptin remains in the fat line, response appears to vary among animals at the dose level used.     

Maze learning and morphology of frontal cortex in adult and aged basal forebrain-lesioned rats

Maze performance and morphology of frontal cortex were assessed in young adult, middle-aged, and aged rats with and without lesions of the nucleus basalis magnocellularis. Although maze performance did not vary with age, neuron number and the thickness of superficial laminae were reduced in aged rats. Lamina II-III neurons were hypertrophied in middle-aged rats relative to both younger and older groups. At all ages, lesions significantly impaired maze performance. In young adult rats, lesions moderately reduced the size of lamina II-III neurons. This effect was more pronounced in middle-aged rats. Lesions in aged rats did not affect neuron size. The neuronal changes seen in middle-aged rats may reflect a compensatory response to the expression of other age-related neuronal changes, which may affect the ability of cortical neurons to respond to lesion-induced loss of cholinergic input.     

Initial validation of Russell's Revised Wechsler Memory Scale: A comparison of normal aging versus dementia.

Results of a study with 29 normal aging volunteers and 29 dementia patients (ages in both groups, 55–85 yrs) indicate that E. W. Russell's (see record 1976-08657-001) Revised Wechsler Memory Scale discriminated between the 2 groups on all variables. Both groups experienced greater loss in figural than in semantic memory. Results suggest that memory loss in normal aging and dementia is a selective rather than a general disability. (1 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taste aversion and the generality of the laws of learning.

Results from research on aversions acquired through the pairing of ingested substances with illness have recently been used to challenge the assumption that there are laws of learning that hold across different species and tasks. The taste aversion literature is selectively reviewed and compared with data from traditional experiments in order to evaluate this challenge. Areas sufficiently documented or controversial to warrant inclusion are associative fluidity (acquisition, retention, extinction), CS and UCS characteristics (specificity, intensity, generalization, hedonic value), temporal relationships (trace conditioning, backward conditioning), obtaining and processing information (novelty, learned irrelevance, blocking, conditioned inhibition, sensory preconditioning, 2nd-order conditioning), and age differences. The conclusion is that in no instance are different principles required to describe taste aversion and traditional learning. In some cases large parametric differences between the 2 research areas are apparent. It is suggested that at the present time it is not necessary to dispense with the notion of general laws of learning. (179 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perturbed dentate gyrus function in serotonin 5-HT2C receptor mutant mice

Serotonin systems have been implicated in the regulation of hippocampal function. Serotonin 5-HT2C receptors are widely expressed throughout the hippocampal formation, and these receptors have been proposed to modulate synaptic plasticity in the visual cortex. To assess the contribution of 5-HT2C receptors to the serotonergic regulation of hippocampal function, mice with a targeted 5-HT2C-receptor gene mutation were examined. An examination of long-term potentiation at each of four principal regions of the hippocampal formation revealed a selective impairment restricted to medial perforant path-dentate gyrus synapses of mutant mice. This deficit was accompanied by abnormal performance in behavioral assays associated with dentate gyrus function. 5-HT2C receptor mutants exhibited abnormal performance in the Morris water maze assay of spatial learning and reduced aversion to a novel environment. These deficits were selective and were not associated with a generalized learning deficit or with an impairment in the discrimination of spatial context. These results indicate that a genetic perturbation of serotonin receptor function can modulate dentate gyrus plasticity and that plasticity in this structure may contribute to neural mechanisms underlying hippocampus-dependent behaviors.