Faecal shedding and intestinal colonization of Salmonella enterica in in-bred chickens: the effect of host-genetic background.

Considerable and reproducible differences were observed in the amount and duration of faecal excretion when in-bred lines of chickens were infected orally with S. enterica serovar Typhimurium at 6 weeks of age after being given a gut flora preparation when newly hatched. Similar but less pronounced results were observed with S. Enteritidis or S. Infantis. Differences in the viable numbers of the inoculated bacteria in caecal contents were detectable within 24 h of inoculation. No major differences were seen in Salmonella-specific serum IgA or IgG titres. Small differences were seen in the numbers of circulating heterophilic cells. Caecal contents taken from the more resistant lines immediately prior to challenge appeared to be no more inhibitory for Salmonella in vivo than contents taken from susceptible lines. The more resistant lines showed a slightly higher rate of intestinal flow, as indicated by the rate of production of faecal droppings, although there was no difference in the rate of emptying of the caeca. In an F1 generation resistance was dominant and not sex-linked. There was no MHC linkage or any association with SAL1, the gene implicated in resistance to systemic salmonellosis in chickens, or NRAMP1.

Rapid protection of gnotobiotic pigs against experimental salmonellosis following induction of polymorphonuclear leukocytes by avirulent Salmonella enterica.

Oral inoculation of 5-day-old gnotobiotic pigs with Salmonella enterica serovar Typhimurium strain F98 resulted in severe enteritis and invasive disease. Preinoculation 24 h earlier with an avirulent mutant of Salmonella enterica serovar Infantis (1326/28) completely prevented disease for up to 14 days (when the experiment was terminated). S. enterica serovar Infantis colonized the alimentary tract well, with high bacterial counts in the intestinal lumen but with almost no invasion into the tissues. Unprotected pigs had high S. enterica serovar Typhimurium counts in the intestines, blood, and major nonintestinal organs. Recovery of this strain from the blood and major organs in S. enterica serovar Infantis-protected pigs was substantially reduced despite the fact that intestinal counts were also very high. Protection against disease thus did not involve a colonization exclusion phenomenon. Significant (P < 0.05) infiltration of monocytes/macrophages was observed in the submucosal regions of the intestines of both S. enterica serovar Infantis-protected S. enterica serovar Typhimurium-challenged pigs and unprotected S. enterica serovar Typhimurium-challenged pigs. However, only polymorphonuclear neutrophils (PMNs) were observed throughout the villus, where significant (P < 0.05) numbers infiltrated the lamina propria and the subnuclear and supranuclear regions of the epithelia, indicating that PMN induction and positioning following S. enterica serovar Infantis inoculation was consistent with rapid protection against the challenge strain. Similarly, in vitro experiments using a human fetal intestinal epithelial cell line (INT 407) demonstrated that, although significantly (P < 0.05) fewer S. enterica serovar Infantis than S. enterica serovar Typhimurium organisms invaded the monolayers, S. enterica serovar Infantis induced an NF-kappaB response and significantly (P < 0.05) raised interleukin 8 levels and transmigration of porcine PMN. The results of this study suggest that attenuated Salmonella strains can protect the immature intestine against clinical salmonellosis by PMN induction. They also demonstrate that PMN induction is not necessarily associated with clinical symptoms and/or intestinal pathology.

Observations on the persistence and vertical transmission of Salmonella enterica serovars Pullorum and Gallinarum in chickens: effect of bacterial and host genetic background.

Commercial laying hens inoculated with a strain of Salmonella enterica ser. Pullorum when they were 4 days old showed no morbidity, but harboured infection until they came into lay, and then produced S. Pullorum-contaminated eggs and infected progeny. There was limited evidence of transmission of maternal immunity to the progeny. Attempts were made to set up similar infections in hens with Salmonella Gallinarum, but without success. Infection either resulted in clinical disease or elimination of the pathogen. Infection of birds when in lay produced a similar result. The possibility of eggs becoming contaminated with S. Gallinarum after they were laid in the nest box was evaluated but there was no evidence for this. In-bred chicken lines with a SalI-susceptible phenotype showed greater localization of S. Pullorum in the reproductive tract than did a SalI-resistant line. In addition, in-bred birds, which were SalI resistant but showed greater susceptibility to intestinal colonization by Salmonella, infected with S. Gallinarum when they were 1 week old, showed longer term persistence in the liver and spleen than did a resistant line.

Olfactory deficits in patients with mild cognitive impairment predict Alzheimer's disease at follow-up.

OBJECTIVE: This study evaluated the predictive utility of olfactory identification deficits in patients with mild cognitive impairment for follow-up diagnosis of probable Alzheimer's disease. METHOD: Ninety outpatients with mild cognitive impairment were examined at 6-month intervals. Matched healthy comparison subjects (N=45) were examined annually. The University of Pennsylvania Smell Identification Test was given at baseline. RESULTS: Olfaction scores were lower in patients with mild cognitive impairment than in healthy comparison subjects. Seventy-seven patients were followed up; 19 were diagnosed with Alzheimer's disease by 2 years. Patients with low olfaction scores (< or =34 of 40), and patients with low olfaction scores who reported no subjective problems smelling, were more likely to develop Alzheimer's disease than other patients. In a Cox proportional hazards model adjusted for age, sex, modified Mini-Mental State score, and education, low olfaction scores did not predict time until development of Alzheimer's disease, but low olfaction scores accompanied by lack of awareness of olfactory deficits predicted time to development of Alzheimer's disease. This effect remained when attention or memory measures replaced modified Mini-Mental State score in the model. In patients with high Mini-Mental State scores (> or =27 of 30), low olfaction with lack of awareness remained a significant predictor of Alzheimer's disease. Olfaction scores of 30-35 showed moderate to strong sensitivity and specificity for diagnosis of Alzheimer's disease at follow-up. CONCLUSIONS: In patients with mild cognitive impairment, olfactory identification deficits, particularly with lack of awareness of olfactory deficits, may have clinical utility as an early diagnostic marker for Alzheimer's disease.

Preliminary study of two methods of treatment for laryngeal nodules.

To date, a limited number of formal studies have assessed the efficacy of voice therapy for laryngeal nodules. The present study represents a preliminary stage of inquiry in a series of planned studies on this topic. Thirteen women with nodules participated as paid subjects. Some subjects received "confidential voice therapy," some received "resonant voice therapy," and some received no therapy (control condition) over a period of approximately 2 weeks. Pre- and post-therapy measures of phonatory effort, auditory-perceptual status of voice, and laryngeal appearance provided evidence of a benefit from therapy. Baseline measures were then repeated 2 weeks after therapy was terminated. The final results indicated that, for auditory-perceptual and phonatory effort measures, the likelihood of benefiting from therapy directly covaried with compliance scores (reflecting the reported extraclinical utilization of the therapy technique), but not with therapy type (confidential vs. resonant voice therapy). At this level, the results point to the importance of assessing not only therapy type but also compliance in future, larger studies. A series of other positive and negative factors in the present research design were identified based on the results. These should be considered in future studies.

Role of elaborative and perceptual integrative processes in perceptual-motor performance.

Three experiments address the dependence of both explicit and implicit memory performance on elaborative processes for a perceptual-motor task, pursuit rotor. Explicit memory performance was reflected by recognition of previously encountered pursuit rotor stimuli. Implicit memory performance (priming) was identified in Experiment 1 as an advantage in pursuit rotor performance for old stimuli that Ss failed to explicitly recognize. In Experiments 2 and 3, the types of strategies that Ss engaged in during training and test phases were manipulated. Results indicated that explicit memory performance depended on elaborative processes that emphasized which specific stimuli were encountered, whereas reliable implicit memory performance appeared only under a control no-instruction condition. Discussion focuses on attention to perceptual-integrative processes for priming.

Comparison of aerodynamic and electroglottographic parameters in evaluating clinically relevant voicing patterns.

The purpose of the present study was to identify one or more aerodynamic or electroglottographic measures that distinguish among voicing patterns that are clinically relevant for nodule pathogenesis and regression: a presumably pathogenic pattern (pressed voice), a neutral pattern (normal voice), and two presumably therapeutic patterns (resonant voice and breathy voice). Trained subjects with normal voices produced several tokens of each voice type on sustained vowels /a/, /i/, and /u/. For each token, maximum flow declination rate, alternating current flow, and minimum flow were obtained from inverse-filtered airflow signals, and closed quotient and closing time were obtained from electroglottographic signals. The results indicate that for /a/ and /i/ (but not for /u/), the closed quotient provides a sensitive tool for distinguishing the voice types in physiologically interpretable directions. Further, post-hoc analyses confirmed a direct relationship between the closed quotient and videoscopic ratings of laryngeal adduction, which previous work links to nodule pathogenesis and regression.

Effect of hydration treatments on laryngeal nodules and polyps and related voice measures.

In this study, a double-blind, placebo-controlled approach was used in assessing the effectiveness of hydration treatments in the clinical management of selected voice disorders. Six adult female patients with laryngeal nodules or polyps each received 5 consecutive days of hydration treatment and 5 consecutive days of placebo/control treatment. The combined results indicated improvements in voice and in laryngeal appearance following both placebo/control and hydration treatments as compared with baseline. However, the greatest improvements were obtained following the hydration treatment. Although caution about generalization of the effects to the typical clinical situation is emphasized, the study provides preliminary evidence of a therapeutic benefit from hydration treatments in patients with nodules or polyps. Based on previous theoretical work, hydration effects may be related to reductions in the viscosity of vocal fold tissue, although other explanations are also possible.