Daily rhythms of heart rate, temperature and locomotor activity are modified by anaesthetics in rats: a telemetric study

The aim of this study was to evaluate the effect of anaesthesia (ether or ketamine) on daily rhythms of temperature (T), heart rate (H) and locomotor activity (A) in unrestrained rats by using implanted radio-telemetry transmitters. T, H and A were measured every 10min, in Wistar male rats, and analysed using Cosinor. The mean±SEM days needed, after surgical implantation, to detect a daily rhythm in H, T and A were also assessed. Six rats were anaesthetized for about 50min either by ketamine or ether in a 3 by 3 cross-over design. Mesors, amplitudes and acrophases of T, H and A were calculated three days before (D-3; D-2; D-1), the day of anaesthesia (D0) as well as the three following days (D1; D2; D3). ANOVA was performed in order to detect, firstly a possible effect due to the order of application of anaesthesia, secondly a significant difference between ether or ketamine-induced anaesthesia and finally a modification of the mesors, amplitudes and acrophases of T, H and A, induced by each anaesthesia, for D0, D1, D2 and D3 when compared to D-1. Our results indicate: (1) Alterations of the acrophases, mesors and amplitudes, except for the amplitude of A, of the daily rhythms of T, H and A on D0 of ketamine anaesthesia while regarding ether anaesthesia only amplitude of T and H and acrophase of A were modified on D0. Some of these modifications were still observed on the days following anaesthesia. A significant difference between ether and ketamine-induced anaesthesia was also observed. (2) A non-detection of T, H and A daily rhythms after surgical implantation, which was not observed after injection of either ether or ketamine alone. Almost 10 days were needed to detect a significant daily rhythm for T, H and A. The authors suggest that, the general anaesthetic agent was responsible for a perturbation of the mesors, amplitudes and acrophases of the daily rhythms of H, T and A while the non-detection of these rhythms after implantation was more due to the surgical aggression. Received: 10 September 1996 / Accepted: 30 January 1997     

Factors related to admission of new patients consulting geriatric psychiatric services in montreal

The development of and the demand for geriatric psychiatric services (GPS) have increased over the past decade. Psychopathology, autonomy, physical disorders, sociodemographics, social support and caregivers' burden have all been advanced as influencing the elderly's risk of hospitalization. These factors were examined in a 1-year prospective study of 87 new patients consulting a catchment-area GPS. Standardized assessments were used, including both patients' and caregivers' independent measures of patients' social network. Entry points to the study were as follows: 70.1% of patients came from an outpatient clinic and 25.3% were admitted directly to psychiatric wards. Subjects were followed up 1 year after discharge or first contact. Overall, 47.1% of the sample was admitted to a higher-supervision setting during the 1-year follow-up, including 20.7% of the total sample admitted to GPS wards. Multivariate logistic regression analysis indicated different factors influencing admission according to the definition of admission. Loss of autonomy was a key factor related to both psychiatric and overall admissions. Previous admission was a predictor of psychiatric admissions only. Relatives' strain and not living with spouse were predictors of overall admissions. The results indicate that functional consequences of disease (eg loss of autonomy) and resilience of relatives are key in predicting the elderly's need for greater supervision.     

Inverse correlation between the proportion of salivary bacteria inhibiting Streptococcus mutans and the percentage of untreated carious teeth

To evaluate the role of inhibitory substances produced by bacteria in the oral cavity, we estimated, by a deferred test on Todd-Hewitt agar enriched with hemin and vitamin K, the proportion of bacteria that inhibited or stimulated the growth of Streptococcus mutans and Porphyromonas gingivalis , from the saliva of 109 patients (54 males and 55 females) attending our dental clinics. The patients, aged from 8 to 75 years old (mean: 31±18 years), were randomly selected whatever the reason for their visit. The results, evaluated with the Spearman rank test, indicated that there was no statistically significant ( P >0.05) correlation between the proportion of salivary bacteria inhibiting or stimulating P. gingivalis with the Community Periodontal Index of Treatment Needs (CPITN), the number of carious, missing and filled teeth, or with the decayed, missing and filled teeth index (DMFT). Also, no statistically significant correlation was observed between the proportion of salivary bacteria stimulating the growth of S. mutans and the above mentioned health indexes. However, a statistically significant ( P <0.005) negative correlation was found between the percentage of cultivated bacteria that inhibit S. mutans and the percentage of untreated carious teeth as well as with the CPITN. The results thus indicate a possible role for inhibitory substances produced by bacteria in the maintenance of oral health.     

Functional and anatomical memory indices in patients with or at risk for Alzheimer's disease.

We investigated the sensitivity of the P300 event-related brain potential (ERP) recorded during a memory-demanding task to memory function in subjects with dementia of the Alzheimer's type (DAT), those with mild cognitive impairment (MCI), and normal elderly controls. We also explored the ability of neuropsychological (delayed verbal memory), neuroanatomical (MRI-based hippocampal volume), and electrophysiological (memory search P300 amplitude) memory measures to distinguish between the three subject groups using discriminant function analyses. Fourteen patients with DAT, 16 with MCI, and 15 age- and education-matched controls were tested. P300 amplitude was reduced in DAT subjects at all levels of memory load; however, it did not differ between MCI and control subjects. Delayed verbal memory performance best discriminated DAT from MCI and control subjects, while delayed verbal memory and hippocampal volume best discriminated MCI subjects from controls. These results support the utility of neuropsychological and neuroanatomical measures in diagnosing dementia and do not support the notion that P300 amplitude is sensitive to mild memory dysfunction when measured using the current task.     

On our way to targeted therapy for cachexia in cancer?

PURPOSE OF REVIEW: Cachexia, the occurrence of involuntary weight loss due to loss of adipose tissue and skeletal muscle mass, is among the most common and devastating symptoms in patients with advanced cancer. It is a significant factor contributing to the poor performance status and high mortality rate of these patients, and is a distressing problem for both patients and their families. Despite extensive research in an attempt to better understand the mechanisms involved, progress in the management of cancer cachexia has been slow. RECENT FINDINGS: The pathogenic mechanisms of cachexia and anorexia are multifactorial, but cytokines and tumour-derived factors are known to play a significant role, thereby representing suitable therapeutic targets. Moreover, recent advances in the field of molecular biology have shed light on other mediators involved in the mechanisms leading to muscle wasting, thus increasing potential targets for new therapies. SUMMARY: This review will focus on recent findings in relation to the molecular pathways leading to muscle wasting that have improved our current understanding of cachexia and will direct the future management of cachexia in cancer towards targeted therapies.     

A cohort study of indoor nitrogen dioxide and house dust mite exposure in asthmatic children

OBJECTIVE: The purpose of this study was to investigate dose-response relationships between asthma symptoms and indoor nitrogen dioxide (NO2) and house dust mite allergen (HDM) in children. METHODS: Asthmatic children from 18 primary schools in Adelaide, Australia, kept a daily symptoms diary over 12 weeks. Home and classroom NO2 levels were measured repeatedly in winter 2000. HDM levels were obtained from beds. Lung function tests were performed at the beginning and at the end of the study period. RESULTS: Data on exposure and respiratory outcomes were gathered for 174 children. For school exposure, the estimated relative symptom rate (RR) for a 10-ppb increase in NO2 for difficulty breathing during the day was 1.09 (95% confidence interval [CI] = 1.03-1.15), at night 1.11 (95% CI = 1.05-1.18), and for chest tightness at night 1.12 (95% CI = 1.07-1.17). Significant symptom rate increases were also found for kitchen NO2 exposure. This was supported by a negative dose-response relationship between percentage predicted forced expiratory volume in 1 second and NO2 (-0.39%; 95% CI = -0.76 to -0.02) for kitchen exposure. Significant threshold effects using a 10-microg/g cutoff point for HDM exposure were established in the sensitized children for nighttime wheeze (RR = 3.62, 95% CI = 1.49-8.77), daytime cough (RR = 1.64, 95% CI = 1.14-2.36), and daytime asthma attack (RR = 1.95, 95% CI = 1.06-3.60). CONCLUSION: This study has established reliable risk estimates for exacerbations of asthma symptoms in children based on dose-response investigations of indoor NO2 and HDM.     

Zinc and its specific transporters as potential targets in airway disease

The dietary group IIb metal zinc (Zn) plays essential housekeeping roles in cellular metabolism and gene expression. It regulates a number of cellular processes including mitosis, apoptosis, secretion and signal transduction as well as critical events in physiological processes as diverse as insulin release, T cell cytokine production, wound healing, vision and neurotransmission. Critical to these processes are the mechanisms that regulate Zn homeostasis in cells and tissues. The proteins that control Zn uptake and compartmentalization are rapidly being identified and characterized. Recently, the first images of sub-cellular pools of Zn in airway epithelium have been obtained. This review discusses what we currently know about Zn in the airways, both in the normal and inflamed states, and then considers how we might target Zn metabolism by developing strategies to monitor and manipulate airway Zn levels in airway disease.