Characterization and phospholipase D mediation of the angiotensin II priming response in adrenal glomerulosa cells

Bovine adrenal glomerulosa cells are primed by an initial treatment with angiotensin II (AngII) to respond with enhanced secretion to a second exposure to AngII or agents that increase calcium influx. We hypothesized that the mechanism of priming involves a persistent increase in diacylglycerol (DAG) generated via sustained activity of phospholipase D (PLD). In this report, we sought to define the time frame of this priming response as well as determine its mechanism using assays of aldosterone secretion, PLD activation, and radiolabeled diacylglycerol levels. We found that in primary cultures priming was observed for up to 50 min after AngII washout, suggesting that the priming window is protracted in these cultures relative to freshly isolated cells. The phorbol ester, phorbol 12,13-dibutyrate (PDBu), was used to investigate the role of sustained PLD activation in the persistent DAG and priming responses. PDBu was able to both prime glomerulosa cells to respond with enhanced secretion to AngII and elicit a persistent increase in DAG after PDBu washout. This persistent increase in DAG levels with an initial exposure to PDBu or AngII was not the result of maintained PLD activity after agent removal because PLD activation returned to basal levels by 30 min after washout. Finally, inhibition of PLD signaling during the initial AngII treatment inhibited the subsequent response to AngII or another agent that increases calcium influx. Thus, our results suggest that persistent DAG resulting from PLD signaling mediates the priming response to AngII or PDBu.

A decade on: has the use of integrated care pathways made a difference in Lanarkshire?

This article aimed to: (1) review the work carried out in Lanarkshire between 1996 and 1999 on a Scottish Executive funded project and (2) to discuss the situation from 1999 to 2006. (1) This 3-year project led to the successful development and implementation of over 100 integrated care pathways in an urban teaching hospital (Glasgow) and a district general hospital (Lanarkshire) and was the first in-depth study of integrated care pathways to be undertaken in Scotland. The main report on the project was produced in 1999 (Clinical Audit and Quality using Integrated Pathways of Care) and reported increased adherence to British Thoracic Society and Scottish Intercollegiate Guidelines Network guidelines and multiple best practice statements, and improved standards of documentation. The general findings were that process indicators were improved by integrated care pathway use and there was some suggestion of improved length of stay with no apparent effect on outcome. Evidence was found that integrated care pathways have made a difference for both patients and staff. (2) This provides an update of integrated care pathway development in a changing environment within NHS Lanarkshire and examines some of the key factors for success.

Randomized clinical trial of routine preoperative duplex imaging before varicose vein surgery (Br J Surg 2005; 92: 688-694)

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses can be sent electronically via the BJS website (http://www.bjs.co.uk) or by post. All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length. Letters submitted by post should be typed on A4-sized paper in double spacing and should be accompanied by a disk.

Role of bombesin-related peptides in the mediation or integration of the stress response

In addition to the relatively well established role of corticotropin-releasing hormone (CRH) and arginine-vasopressin (AVP) in the mediation of the stress response, there is reason to believe that bombesin-like peptides (BN-LPs) may also contribute to the mediation or integration of these responses and thus might be considered as putative 'stress peptides'. This review provides evidence supporting this contention by showing that (i) BN-LPs are present at brain sites known to be activated by stressors, (ii) stressor exposure alters utilization of BN-related peptides, (iii) exogenous BN administration mimics the endocrine, autonomic and/or behavioral effects elicited by stressors, and (iv) antagonism of BN action attenuates the behavioral and/or neurochemical effects of stressors or of exogenously administered peptide. The evidence presented also suggests that BN-LPs mediate their stress-relevant effects through activation of CRH and/or AVP neurons. Several hypothetical mechanisms for such peptidergic interactions are discussed as to the implications of considering BN-LPs as 'stress peptides'.

Post-discharge surgical wound infection surveillance in a provincial hospital: follow-up rates, validity of data and review of the literature

BACKGROUND

Numerous studies suggest that many surgical site infections (SSI) come to light only after discharge from hospital. With increasing trends towards shorter length of stay and ambulatory day surgery, post-discharge surveillance may become necessary for all infection control programs, but the methodology has yet to be validated and standardized. The overall aim of the present study was to examine the impact of effective post-discharge SSI follow up on the overall SSI rate.

METHODS

A prospective targeted surveillance programme of 1291 surgical procedures was conducted at St John of God Health Care Geelong using the standardized National Nosocomial Infections Surveillance (NNIS) METHOD: Questionnaires were sent to surgeons and the results rigorously chased up. Factors giving rise to high follow-up rates and the relationship between follow up, attrition bias and validity of data were explored using a literature search.

RESULTS

A post-discharge follow-up rate of 98.7% was achieved. When the post-discharge data were included, the overall SSI rate (6.0% (95% CI: 4.7-7.4)) was more than double that in hospital (2.7% (95% CI: 1.9-3.8)).

CONCLUSIONS

An effective post-discharge follow-up programme significantly increased the SSI rate. From the authors' experience and a literature survey, possible ways to achieve high follow-up rates were suggested. It was also recommended that professional and regulating bodies in Australia be encouraged to standardize methodology and set minimum follow-up rates for post-discharge SSI surveillance. Increasing use of computerized hospital database systems for automated data gathering and processing should make this more practicable.

Cognitive deficits associated with a recently reported familial neurodegenerative disease: familial encephalopathy with neuroserpin inclusion bodies

BACKGROUND

We recently discovered an autosomal dominant disease causing a progressive dementia. The disease is caused by a point mutation in the gene coding for the serine protease inhibitor (ie, serpin) neuroserpin. The mutation results in an unstable neuroserpin protein that readily aggregates into intraneuronal inclusions that we identify as Collins bodies. The bodies are distributed throughout the cerebral hemispheres but are significantly more numerous in the cortex and the substantia nigra. We have named the disease familial encephalopathy with neuroserpin inclusion bodies (FENIB).

OBJECTIVES

To describe the cognitive and neurophysiological changes exhibited by individuals with FENIB and to correlate the phenotypic expression of the disease with the neuropathological findings.

DESIGN

Multiple case studies using neuropsychological assessment, electroencephalography (EEG), magnetic resonance imaging (MRI), and single-photon emission computed tomographic (SPECT) studies of family members were performed. Using these measures, we also compared family members in whom the mutation is present with family members in whom the mutation was absent to control for nonspecific familial factors.

SUBJECTS

Nine individuals (5 women, aged 31-64 years; 4 men, aged 43-67 years) from 2 generations of family members related to the first reliably identified individual with symptoms of this disease. Symptoms, by self-report and reports of other family members, ranged from asymptomatic to severe dementia. Six of the 9 individuals carried the disease mutation.

RESULTS

All subjects with the mutation demonstrated some cognitive changes, with the greatest demonstrated by subjects older than 40 years. The changes included restricted attention, concentration, and response regulation functions, reduced controlled oral fluency (word-list generation), and restricted visuospatial organization. In general, recall memory was not as affected as other cognitive domains. The most severely affected subject demonstrated global dementia with prominent frontal lobe features. Findings on SPECT showed anomalies limited to frontal areas in the less affected subjects and more global, patchy areas of hypoperfusion in the more severely affected subjects. The 3 oldest and most affected subjects demonstrated slowing on EEG findings. The MRI findings were noncontributory except in the 2 most severe cases, which showed global cortical atrophy.

CONCLUSIONS

Cognitive changes in mildly to moderately affected subjects were characterized by deficits in frontal and frontal-subcortical area-dependent processes. Continued progressive deterioration of cerebral functions with relative sparing of recall memory suggests a unique dementia associated with this disease.

Differential impact of predator or immobilization stressors on central corticotropin-releasing hormone and bombesin-like peptides in Fast and Slow seizing rat

Lines of rats selectively bred for amygdala excitability, as reflected by kindling rates in response to electrical stimulation, also exhibit differences in tests of anxiety. Inasmuch as corticotropin-releasing hormone (CRH) and bombesin (BN) have been associated with anxiety, regional levels and release of these peptides, as well as plasma adrenocorticotropic hormone (ACTH) and corticosterone, were assessed in 'Slow' and 'Fast' seizing rats following predator exposure (ferret) or immobilization. Ferret exposure elicited a greater increase of plasma ACTH and corticosterone concentrations in the Slow than in the Fast rats. In contrast, immobilization provoked a greater rise of plasma ACTH levels in the Fast rats, paralleling the vigorous struggling observed in this line. In Slow rats, stressor exposure elicited increased levels of ir-BN at the anterior hypothalamus, and increased ir-CRH at the median eminence/arcuate nucleus (Me/Arc), paraventricular hypothalamic nucleus (PVN) and pituitary (Pit), whereas decreased levels of ir-BN were found at the nucleus tractus solitarius (NTS). Fast rats likewise showed decreased ir-BN at the NTS, but unlike the Slow rats, ir-CRH was reduced in the Me/Arc, PVN and Pit in response to both stressors. In vivo microdialysis experiments revealed that in response to ferret exposure, the Slow rats showed a greater CRH release at the central nucleus of the amygdala (CeA) as compared to Fast rats. However, immobilization elicited a more pronounced release of CRH in Fast than in Slow rats. Taken together, the results demonstrate that these two lines of rats show differential endocrinological and neurochemical response patterns to these stressors.

ANPs effect on MARCKS and StAR phosphorylation in agonist-stimulated glomerulosa cells

Atrial natriuretic peptide (ANP) is a cardiac hormone that inhibits aldosterone secretion induced by all physiologic agonists. The purpose of this study is to explore ANP-induced changes in the phosphorylation of myristoylated alanine-rich C-kinase substrate (MARCKS) and the steroidogenic acute regulatory protein (StAR), in AngII or K(+)-stimulated glomerulosa cells. The data show that ANP completely inhibits the phosphorylation of MARCKS and partially inhibits that of StAR in cells stimulated with K(+). ANP also partially inhibits MARCKS phosphorylation but does not affect StAR phosphorylation in cells stimulated with AngII. These effects appear to be cGMP-independent and at least partially dependent on inhibition of protein kinase C (PKC). To our knowledge, this is the first report of ANP modulating either MARCKS or StAR phosphorylation in [(32)P]-labeled cells. The data also support the hypothesis that ANP inhibits aldosterone secretion acting as a step involved in cholesterol transport to the mitochondria.

Central bombesin activates the hypothalamic-pituitary-adrenal axis. Effects on regional levels and release of corticotropin-releasing hormone and arginine-vasopressin

While corticotropin-releasing hormone (CRH) is a primary regulator of the hypothalamic-pituitary-adrenal (HPA) axis, the mechanism(s) triggering the release of this corticotropin (ACTH) secretagogue remains unknown. Stressful and appetitive events evoke the release of not only CRH but also of bombesin (BN)-like peptides. Furthermore, CRH antagonists attenuate the endocrine and behavioral effects of BN, suggesting that BN-like peptides may mediate their effects via CRH release. An initial (mapping) study revealed that centrally administered BN (0.25 or 0.5 microg i.c.v.) increased circulating corticosterone and ACTH levels and decreased immunoreactive (ir)-CRH at the nucleus of the solitary tract, ventromedial (VMH) and anterior hypothalamic nuclei, and the central amygdaloid nucleus. Whereas BN treatment decreased ir-vasopressin (AVP) at the VMH, it elevated levels of this peptide in the hypothalamic paraventricular and median eminence/arcuate (Me/Arc) regions. Dynamic, in vivo release experiments (using push-pull perfusion) revealed that BN evoked the release of ir-CRH and ir-AVP from the Me/Arc and increased interstitial levels of these secretagogues at the anterior pituitary. These results suggest that BN-like peptides may regulate certain hypothalamic and extrahypothalamic circuits, including the HPA axis, by affecting regional utilization of ir-CRH and ir-AVP, and/or by provoking the release of these peptides at the Me/Arc, thus increasing their availability downstream at the anterior pituitary and increasing circulating ACTH and corticosterone levels.

Bombesin-induced HPA and sympathetic activation requires CRH receptors

Central administration of bombesin (BN) (into the ventricular system) increased circulating levels of ACTH, corticosterone, epinephrine, norepinephrine and glucose, indicating that this peptide activates the hypothalamic-pituitary-adrenal (HPA) axis and sympathetic nervous system. We then assessed the potential contribution of corticotropin-releasing hormone (CRH) system, in the mediation of these BN effects. Blockade of CRH receptors with alphah-CRF (10 microg) attenuated or blocked the BN-induced rise in plasma ACTH, epinephrine, norepinephrine, glucose and corticosterone levels. These findings support the notion that BN-induced HPA axis and sympathetic activation are mediated, at least in part, via activation of CRH neurons.

Influence of psychogenic and neurogenic stressors on neuroendocrine and central monoamine activity in fast and slow kindling rats

The central neurochemical and neuroendocrine effects of a psychogenic (ferret exposure) and a neurogenic (restraint) stressor were assessed in rats that had been selectively bred for differences in amygdala excitability manifested by either Fast or Slow amygdala kindling epileptogenesis. While these rat lines differ in their emotionality, their behavioral styles were dependent on the nature of the stressor to which they were exposed. During restraint, the Slow rats were mostly immobile, while Fast rats persistently struggled. In contrast, Fast rats were more immobile in response to the ferret. Yet, the more emotional Slow rats exhibited a greater corticosterone response to the ferret, while comparable corticosterone responses between lines were evident following restraint. Although both stressors influenced norepinephrine (NE), dopamine (DA) and/or serotonin (5-HT) activity in brain regions typically associated with stressors (e.g., locus coeruleus, paraventricular nucleus of the hypothalamus, nucleus accumbens, prefrontal cortex), considerable amine alterations were evident in the medial and basolateral amygdala nuclei, but not in the central nucleus. Moreover, greater NE changes were apparent in the medial amygdala of the left hemisphere. Similarly, DA alterations also were greater in the left medial amygdala in response to stressors. Despite very different behavioral styles, however, the two lines often exhibited similar amine alterations in response to both stressors.

The potential of intradialytic parenteral nutrition: A review

Malnutrition is common in chronic hemodialysis (CHD) patients and is strongly related to increased morbidity and mortality. Among the various approaches to treat malnutrition in this patient population, intradialytic parenteral nutrition (IDPN) is the treatment of choice for a small but important percentage of malnourished CHD patients. However, the new revised policies relating to IDPN reimbursement by Medicare in the US have made it very difficult to qualify patients for this potentially useful therapy. This restrictive policy was adopted mainly because there are no clear data that support IDPN use or efficacy. Studies to date in the literature do not provide clear documentation of the benefits of IDPN or their cost-effectiveness. The purpose of this review is to critically evaluate studies relating to the use of IDPN as a potential therapy to treat malnutrition in CHD patients and to discuss potential trials to prove its cost-effectiveness.

Bioelectrical impedance analysis in dialysis patients

Identification of malnutrition is imperative in chronic dialysis patients. Bioelectrical impedance (BIA) is a noninvasive method to measure body composition and estimate total body water (TBW), lean body mass (LBM) and body cell mass (BCM). Studies suggest BIA has good reliability as compared to other accepted methods of body composition analysis. Preliminary data also suggest that BIA-derived parameters (reactance and phase angle) predict clinical outcome in chronic hemodialysis patients. Overall, BIA is a promising nutritional assessment tool to monitor health status, long-term follow-up, tailor nutrition support, and detect early subtle losses of LBM in chronic dialysis patients.

The effects of knee extensor and flexor muscle training on the timed-up-and-go test in individuals with rheumatoid arthritis

BACKGROUND AND PURPOSE

Rheumatoid arthritis frequently results in functional impairment. This study investigated the effect of a specific exercise regimen on function.

METHOD

A randomized controlled assessor-blinded (N = 36) compared the effect of knee extensor and flexor muscle training on pain, the timed up and go (TUG) test and the Health Assessment Questionnaire in subjects with non-acute rheumatoid arthritis.

RESULTS

Knee extensor and flexor muscle training increased isokinetic torques at speeds of 60 degrees/sec-1 and 120 degrees/sec-1 as measured by an isokinetic dynamometer (p = 0.02-0.003). The experimental group experienced a reduction in pain (p = 0.03), an improvement in TUG time (p = 0.01) and in function as measured by the Health Assessment Questionnaire (p = 0.04).

CONCLUSIONS

Specific knee muscle training can be administered safely in people with non-acute rheumatoid arthritis, and may produce functional benefits.

Neural plasticity, neuropeptides and anxiety in animals--implications for understanding and treating affective disorder following traumatic stress in humans

Exposure of rats to cats (predator stress) lastingly increases rodent anxiety-like behavior (ALB) in the elevated plus-maze. Previous work shows that lasting changes in ALB following predator stress depend on NMDA and CCKB receptors. In this paper we describe the effects of differing degrees of predator exposure on behavior. Effects depend on the behavioral measure. In general, exposure to predator odor is less provocative of lasting change in ALB than is unprotected exposure to a cat. In addition, we examine the development of effects of unprotected predator exposure over time. Lasting effects on ALB begin at 30 min to 1 h after predator stress and persist for at least 3 weeks. We also report a complex pattern of effects of predator stress on neuroendocrine and stress peptide (bombesin, CRF and AVP) levels in a variety of brain areas. Not surprisingly, predator exposure increases plasma levels of corticosterone and ACTH. Central changes in peptide content in the hypothalamo-pituitary axis, related hypothalamic nuclei, limbic and brain stem areas are also noted. Finally, path analysis demonstrates a replicable relationship between cat behavior, rat defensive behavior and degree of increase in ALB one week later. It is proposed that behavioral changes following predator stress may model anxiety associated with PTSD.

A reduction in repeat falls in a private psychiatric hospital

Falls are of particular concern in psychiatric hospitals where many patients are taking psychotropic medication that may produce postural hypotension. The research considered falls in a private psychiatric hospital before and after the introduction of a hospital policy to measure blood pressure, both lying and standing, after a patient had fallen. Falls, and the injuries associated with them, occurred predominantly among elderly patients. The results of the study showed that the introduction of the policy resulted in more frequent measurement of blood pressure and was associated with fewer repeat falls.

Stressor-induced corticotropin-releasing hormone, bombesin, ACTH and corticosterone variations in strains of mice differentially responsive to stressors

The effects of brief stressor exposure on hypothalamic-pituitary-adrenal (HPA) functioning was assessed in two strains of mice shown to be differentially responsive to stressors. Mild stress (1 min of cold swim, 20 C) led to marked elevations of plasma ACTH and corticosterone concentrations in the stress-reactive BALB/cByJ and the stress-resistant C57Bl/6ByJ mice. Moreover, it was observed that the strains differed in basal CRH content within the amygdala and the paraventricullar nucleus (PVN). Within 1 min of cold swim, the CRH changes were detected in these brain regions in BALB/cByJ mice, but were less apparent in C57Bl/6ByJ mice. Following a chronic stressor regimen, the marked elevations of plasma ACTH associated with acute stressors in BALB/cByJ mice were diminished. In contrast, in C57Bl/6ByJ mice in which acute stressors hardly affected ACTH concentrations, the chronic stressor regimen lead to a marked increase of plasma ACTH. Taken together, data indicate that the stress reactivity differences seen in the two strains of mice are not limited to ACTH and corticosterone, but are also detected with respect to CRH within the amygdala and PVN. Furthermore, the suggestion is offered that the reactivity differences in the two strains of mice may have lead to different profiles of ACTH secretagogues and hence the response profile to later acute and chronic stressors differed in these strains of mice.

Aversive and appetitive events evoke the release of corticotropin-releasing hormone and bombesin-like peptides at the central nucleus of the amygdala

There is wide agreement that corticotropin-releasing hormone (CRH) systems within the brain are activated by stressful stimuli. There is also mounting evidence for the role of bombesin (BN)-like peptides in the mediation of the stress response. To date, however, the extent to which other stimuli increase the activity of these peptidergic systems has received little attention. In the present investigation we validated and used in vivo microdialysis sampling followed by ex vivo radioimmunoassays to monitor the release of CRH and BN-like peptides during appetitive (food intake) and stressful (restraint) events. It is demonstrated for the first time that the in vivo release of CRH and BN-like peptides at the central nucleus of the amygdala was markedly increased by both stressor exposure and food ingestion. In fact, the meal-elicited rise of CRH release was as great as that associated with 20 min of restraint stress. Paralleling these findings, circulating ACTH and corticosterone levels were also increased in response to both food intake and restraint. Contrary to the current views, these results indicate that either food ingestion is interpreted as a "stressful" event by certain neural circuits involving the central amygdala or that the CRH- and BN-related peptidergic systems may serve a much broader role than previously envisioned. Rather than evoking feelings of fear and anxiety, these systems may serve to draw attention to events or cues of biological significance, such as those associated with food availability as well as those posing a threat to survival.

Are bombesin-like peptides involved in the mediation of stress response?

The neurochemical mechanisms underlying the coincident activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system in response to stress remain unclear. Central injection of the neuropeptide bombesin (BN) potently stimulates the release of epinephrine from the adrenal medulla, adrenocorticotropic hormone (ACTH) from the pituitary gland, and elicits behaviors typically associated with increased emotionality and arousal. The current studies assessed whether stress is associated with 1) fluctuations in the endogenous regional levels of BN-like peptides and/or 2) changes in BN receptor density. Male Sprague-Dawley rats received either no treatment or were subjected to acute immobilization stress for 10, 30 or 120 min. Plasma ACTH levels increased in response to stress, peaking at 30 min. BN-like immunoreactivity increased significantly at the hypothalamus and medulla, within 30 min; however with more sustained immobilization (120 min) BN-like immunoreactivity declined to control levels. Levels of BN-like peptides remained unchanged in several other regions, including the hippocampus, striatum, midbrain, pituitary, and pons. Autoradiographic analysis revealed that the density of BN receptor varied in a regionally specific manner. Significant stress related increases in binding were found at the nucleus of the solitary tract (at 30 and 120 min), and at the paraventricular (at 120 min) and arcuate nuclei (at 120 min) of the hypothalamus. These data indicate the BN-like peptides may play a role in the mediation and/or modulation of response to stress.

Pharmaco-ontogeny of bombesin's suppression of food intake and its attenuation by histamine H3 receptor agonists

Bombesin (BN) administration has been shown to suppress food intake across diverse species. Preliminary results have shown that BN elicits a satiety-like state from postnatal day (PD) 1, through unknown mechanism(s). We have recently shown that in adult rats, alpha-methyl histamine (alpha-MH), a selective H3 receptor agonist that inhibits the release and synthesis of histamine, blocks the feeding suppressant effects of BN. The objective of this study was to determine if such a mechanism was operation at birth or whether it developed over time. Thus effects of histamine H3 receptor agonists as well as BN-histamine interactions in the regulation of food intake were assessed during early development. On PD 1, 5, 10 and 15, groups of food deprived Sprague-Dawley rat pups (n = 8-12) were injected with BN alone (0 (saline), 0.006, 0.06 or 0.6 mg/kg, s.c.), H3 receptor agonists alone (alpha-MH or Imetit (3 or 5 mg/kg s.c.)) or the combination of BN and H3 receptor agonists, and their ingestive behavior was monitored. Results confirmed that pups were sensitive to feeding suppressant effects of BN starting from PD 1. Imetit or alpha-MH either failed to affect food intake or at certain time points enhanced food intake. Pretreatment with the H3 receptor agonists significantly attenuated the feeding suppressant effects of BN, suggesting that early in ontogeny, BN may suppress food ingestion possibly by facilitating histamine release at some relevant site(s).

Predicting episodic memory performance of very old men and women: contributions from age, depression, activity, cognitive ability, and speed

Regression models were developed to explain age-related and total variance in memory and to determine the independent contribution from general processing speed, having taken into account cognitive and noncognitive individual differences. Episodic memory was assessed for 3 tasks in a population-based sample of 951 adults comprising 515 men and 436 women (aged 70-96, M = 77.6, SD = 5.5). Correlations between age and memory accounted for 6%-9% of the variance. Hierarchical multiple regressions showed a reduction in this age-related variance by up to 94%, after entering gender, depression, health, cognitive status, activities, and speed. General processing speed was the major mediator of age-related variance in memory. Although both the age-related variance and the speed-related variance in memory were significantly reduced by prior entry of other individual differences variables for all 3 tasks, speed remained a significant mediator of remembering, and negligible differences in the residual age-related variance were observed by inclusion of other background variables.

Influence of psychogenic and neurogenic stressors on endocrine and immune activity: differential effects in fast and slow seizing rat strains

Variations of plasma ACTH and corticosterone, as well as splenic macrophage activity and mitogen-induced cell proliferation, were determined in rats following 15 min of either the neurogenic stressor of restraint or by a purely psychogenic stressor consisting of exposure to a ferret. The effects of these stressors were assessed in two strains of rats that were selectively bred for either Fast or Slow kindling epileptogenesis triggered in response to amygdala stimulation. The stressors differentially influenced behavioral responses, endocrine activity, and immune functioning, and these effects varied with the strain of rat. In response to restraint the Fast rats exhibited protracted struggling, while the Slow rats tended to be immobile. In contrast, upon ferret exposure the Fast rats showed greater immobility than the Slow rats. The stressors also induced marked elevations of plasma ACTH and corticosterone. Whereas the ACTH and corticosterone increases were more pronounced in response to the ferret in the Slow rats, restraint resulted in a markedly greater rise of plasma ACTH in the Fast strain. Proliferation of splenic lymphocytes in response to Con A and LPS were elevated in Fast seizing rats, while macrophage activity, as determined by oxygen burst following addition of PMA and luminol to splenic mononuclear cells, was greater in the Slow seizing strain. While neither stressor influenced cell proliferation in either the Fast or Slow rats, macrophage activity was greatly suppressed by ferret exposure only in the Slow rats. Taken together, it appears that while stressors influence behavior and immune and endocrine functioning, these effects may vary as a function of the interaction of the strain of rat and the specific type of stressor employed.

Smoking behaviours and beliefs of older Australians

Reviews of the effects of smoking on health have concluded that older smokers can experience considerable health benefits from giving up smoking. In a representative population survey of people aged 15 years and over in South Australia, the percentage of people aged 60 years and over who were smokers was 13.5 per cent (95 per cent confidence interval 10.9 to 16.2 per cent). Compared with smokers aged under 60 years (n = 727), older smokers (n = 88) were significantly more likely: to be less convinced of the effects of smoking on health; to perceive that they were not personally at risk from their smoking in the future; to believe that smoking had not affected their own health so far; and to believe there was a daily level of cigarette consumption that was safe. Strategies to encourage older people to consider more objectively how smoking impairs daily living, including personal disclosure of smoking-related damage through lung-function testing, deserve further research.

Large-volume leukapheresis in pediatric patients: processing more blood diminishes the apparent magnitude of intra-apheresis recruitment

BACKGROUND

Recruitment of progenitors during a large-volume collection, as defined by increasing relative and absolute numbers of progenitors (colony-forming units-granulocyte-macrophage [CFU-GM] of CD34+ cells), has been reported previously.

STUDY DESIGN AND METHODS

To ascertain whether intra-apheresis recruitment occurs in pediatric patients who have undergone mobilization with chemotherapy and granulocyte-colony-stimulating factor (G-CSF), each hour's portion of a 4-hour leukapheresis was collected into separate bags, and assessed by complete blood count, CFU-GM, and CD34+ cell assays. Seven pediatric patients (median age, 7; range, 2-19) were studied in connection with 2 to 4 collections each, for a total of 21 collections (with hourly samples). The collections lasted for 4 hours, at an inlet rate of 1 to 3 mL per kg per minute, for daily processing totals of 5 to 12 blood volumes. (One blood volume [mL] is estimated by the patient's weight in kg x 70 mL/kg.) Smaller (younger) patients had inlet rates exceeding 2 mL per kg per minute, and larger (older) patients had rates of 1 to 1.5 mL per kg per minute. CFU-GM and CD34+ cell counts obtained each hour of the collection and divided by the first hour's value were compared by nonparametric repeated-measures ANOVA.

RESULTS

Second-, third- and fourth-hour CD34+ progenitor cell counts were arithmetically higher than first-hour counts, but the trend did not reach significance (p = 0.1561). Second-hour counts were higher than first-hour counts in the overall analysis (mean +/- standard error [SE], 1.00 and 1.39 +/- 0.1, respectively; p = 0.0525) and in children older than 5 years (1.00 vs. 1.70 +/- 0.30, respectively; p = 0.0259), but not in children younger than 5 years (p = 0.8125). CFU-GM counts did not differ among the 4 hours of collection (p = 0.1717) or between the first and second hour (p = 0.9587).

CONCLUSION

In larger (older) patients, from whom fewer blood volumes were collected, there is a trend toward intra-apheresis recruitment, although less than reported previously. In the smaller (younger) patients, from whom more blood volumes were collected, no trend was observed. Lack of (or submaximal) prior mobilization in previously reported studies may have facilitated intracollection recruitment. Alternatively, the larger number of blood volumes collected from the smaller (younger) patients may have masked intra-apheresis recruitment. The study documents the feasibility of large-volume, 4-hour leukapheresis in pediatric patients.