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Biomedical subjects

O Kelly

Publications and source records attributed to O Kelly.

7 recordsLinked to original sources

The effect of conjugated linoleic acid on calcium absorption and bone metabolism and composition in adult ovariectomised rats.

The effect of conjugated linoleic acid (CLA) on postmenopausal bone metabolism has not been investigated. Therefore, forty-three adult ovariectomised (OVX) rats (8-9 rats per group) were fed either a control diet containing 40 g/kg soyabean oil (SBO diet) or the SBO diet with 0 (control OVX), 2.5, 5 or 10 g/kg of CLA (replacing soybean oil) for 9 weeks. A group of sham-operated (SH) rats were fed the SBO diet. OVX rats had significantly (P<0.05) lower femoral bone mineral density and macromineral concentration, and intestinal Ca absorption compared to SH rats. CLA supplementation had no effect on these parameters. Ex vivo PGE(2) biosynthesis by bone and urinary Pyr and Dpyr (markers of bone resorption) were significantly higher (P<0.001) in control OVX rats compared with SH rats, and were significantly (P<0.001) lowered by CLA supplementation with 5 and 10, but not 2.5 g/kg diet in OVX rats. In conclusion, CLA supplementation appeared to reduce the rate of bone resorption in adult OVX rats.

Animals↗

Murine tumor necrosis factor-alpha sensitizes plasma corticosterone activity and the manifestation of shock: modulation by histamine.

Murine tumor necrosis factor-alpha (mTNF-alpha) results in the sensitization of mechanisms underlying plasma corticosterone activity and sickness behavior, the latter being reminiscent of septic or anaphylactic shock. The mTNF-alpha induced a sensitization of sickness and corticosterone in mice that was attenuated by pretreatment with the combinations of histamine H(1) (diphenhydramine, mepyramine) and H(2) (cimetidine) antagonists. Likewise, coadministration of diphenhydramine and cimetidine prevented the mTNF-alpha-provoked rise of monoamine activity within the posterior hypothalamus. Although dexamethasone ameliorated the mTNF-alpha-induced sensitization of corticosterone, illness behavior was unaffected. It is suggested that mTNF-alpha-induced illness and the neuroendocrine sensitization are mediated by endogenous histamine.

Animals↗

Psychogenic, neurogenic, and systemic stressor effects on plasma corticosterone and behavior: mouse strain-dependent outcomes.

The effects of several stressors were assessed in inbred strains of mice, BALB/cByJ and C57BL/6ByJ, thought to be differentially reactive to stressors. Behavioral reactivity was greater in BALB/cByJ mice with respect to open-field emergence, step-down responding, response to a predator (rat) or to fox urine odor. Neurogenic insults (e.g., footshock, forced swim, restraint) and a systemic stressor (intraperitoneal interleukin-1beta treatment) likewise provoked a greater rise of plasma corticosterone in the BALB/cByJ mice. Psychogenic stressors (e.g., novel open-field exposure, acoustic startle stimuli) also enhanced plasma corticosterone to a greater extent in BALB/cByJ mice, but such an outcome was not apparent following predator-related cues. It appears that whereas stressor reactivity and adrenal glucocorticoid release may be exaggerated in BALB/cByJ mice, such effects may be dependent on the specific characteristic of the stressor situation.

Animals↗

Acoustic startle and fear-potentiated startle in rats selectively bred for fast and slow kindling rates: relation to monoamine activity.

The acoustic startle response, prepulse inhibition, fear-potentiated startle and monoamine activity induced by either, a novel stimulus or a cue previously paired with foot-shock (fear-conditioning), were assessed in rats selectively bred for differences in amygdala excitability (Fast vs. Slow kindling epileptogenesis). Comorbid differences of anxiety, which were dependent both on the rats' behavioural style and the kind of stressor, also characterized these strains. In the present investigation, Slow rats exhibited a greater startle reflex to noise relative to Fast rats, suggesting differences in generalized anxiety, but similar rates of startle habituation and prepulse inhibition. The fear-potentiated startle, however, was greater in Fast rats. When movement of the rat was restricted in a new environment, presentation of a novel stimulus (light) increased norepinephrine, dopamine and/or serotonin activity in brain regions typically associated with stressors (e.g. locus coeruleus, paraventricular hypothalamic nucleus). Generally, these effects were more pronounced in Fast rats, and norepinephrine utilization in the central amygdala was particularly highlighted in response to a conditioned fear stimulus. Thus, while generalized anxiety appeared greater in Slow rats, behavioural and central neurochemical reactivity in response to novel stimuli and to fear-eliciting stimuli, was greater in Fast rats. Similarly, basal dopamine activity in the prefrontal cortex was greater in Fast rats, but dopamine utilization elicited by a novel stimulus was more pronounced in Slow rats. This suggested that relative to Slow rats, dopamine neurons in prefrontal cortex of Fast rats do not react normally to environmental stimuli, and this phenomenon could lead to disturbances of attention or impulsivity.

Acoustic Stimulation↗

The importance of microbiological investigations, medications and artificial feeding in diarrhoea evaluation.

BACKGROUND: Diarrhoea in hospitalised patients is usually attributed to medications especially antibiotics, enteral tube feeding or enteropathogenic bacteria particularly Clostridium difficile. AIMS: The aim of this study was to evaluate the investigations performed on patients who developed diarrhoea during their stay in an acute general hospital. METHOD: Over 18 working days, an unselected group of adult inpatients who developed diarrhoea following their admission to hospital were reviewed. Symptoms, medications, nutritional support and any investigations performed were assessed. RESULTS: Eighty-one patients developed diarrhoea. Forty-nine (60%) were receiving antibiotics prior to the development of symptoms, 30 (37%) were being enterally tube fed, 14 (17%) had positive stool for Clostridium difficile A and B toxin and 3 (4%) had salmonella species positive stool. CONCLUSION: The majority of cases of diarrhoea were related to medications and enteral tube feeding. A small but significant number did develop bacterial infections. In contrast to some suggested guidelines, when investigating hospital acquired diarrhoea, it is considered worthwhile to perform microbiological stool examinations.

Adult↗