Cross-sectional analysis of healthy individuals across decades: Aging signatures across multiple physiological compartments

The study of age-related biomarkers from different biofluids and tissues within the same individual might provide a more comprehensive understanding of age-related changes within and between compartments as these changes are likely highly interconnected. Understanding age-related differences by compartments may shed light on the mechanism of their reciprocal interactions, which may contribute to the phenotypic manifestations of aging. To study such possible interactions, we carried out a targeted metabolomic analysis of plasma, skeletal muscle, and urine collected from healthy participants, age 22-92 years, and identified 92, 34, and 35 age-associated metabolites, respectively. The metabolic pathways that were identified across compartments included inflammation and cellular senescence, microbial metabolism, mitochondrial health, sphingolipid metabolism, lysosomal membrane permeabilization, vascular aging, and kidney function.

Oral nicotinamide riboside raises NAD+ and lowers biomarkers of neurodegenerative pathology in plasma extracellular vesicles enriched for neuronal origin

Declining nicotinamide adenine dinucleotide (NAD+ ) concentration in the brain during aging contributes to metabolic and cellular dysfunction and is implicated in the pathogenesis of aging-associated neurological disorders. Experimental therapies aimed at boosting brain NAD+ levels normalize several neurodegenerative phenotypes in animal models, motivating their clinical translation. Dietary intake of NAD+ precursors, such as nicotinamide riboside (NR), is a safe and effective avenue for augmenting NAD+ levels in peripheral tissues in humans, yet evidence supporting their ability to raise NAD+ levels in the brain or engage neurodegenerative disease pathways is lacking. Here, we studied biomarkers in plasma extracellular vesicles enriched for neuronal origin (NEVs) from 22 healthy older adults who participated in a randomized, placebo-controlled crossover trial (NCT02921659) of oral NR supplementation (500 mg, 2x /day, 6 weeks). We demonstrate that oral NR supplementation increases NAD+ levels in NEVs and decreases NEV levels of Aβ42, pJNK, and pERK1/2 (kinases involved in insulin resistance and neuroinflammatory pathways). In addition, changes in NAD(H) correlated with changes in canonical insulin-Akt signaling proteins and changes in pERK1/2 and pJNK. These findings support the ability of orally administered NR to augment neuronal NAD+ levels and modify biomarkers related to neurodegenerative pathology in humans. Furthermore, NEVs offer a new blood-based window into monitoring the physiologic response of NR in the brain.

Experimenters' sex modulates mouse behaviors and neural responses to ketamine via corticotropin releasing factor

We show that the sex of human experimenters affects mouse behaviors and responses following administration of the rapid-acting antidepressant ketamine and its bioactive metabolite (2R,6R)-hydroxynorketamine. Mice showed aversion to the scent of male experimenters, preference for the scent of female experimenters and increased stress susceptibility when handled by male experimenters. This human-male-scent-induced aversion and stress susceptibility was mediated by the activation of corticotropin-releasing factor (CRF) neurons in the entorhinal cortex that project to hippocampal area CA1. Exposure to the scent of male experimenters before ketamine administration activated CA1-projecting entorhinal cortex CRF neurons, and activation of this CRF pathway modulated in vivo and in vitro antidepressant-like effects of ketamine. A better understanding of the specific and quantitative contributions of the sex of human experimenters to study outcomes in rodents may improve replicability between studies and, as we have shown, reveal biological and pharmacological mechanisms.

Comparative metabolomic analysis in plasma and cerebrospinal fluid of humans and in plasma and brain of mice following antidepressant-dose ketamine administration

Subanesthetic-dose racemic (R,S)-ketamine (ketamine) produces rapid, robust, and sustained antidepressant effects in major depressive disorder (MDD) and bipolar disorder (BD) and has also been shown to effectively treat neuropathic pain, complex regional pain syndrome, and post-traumatic stress disorder (PTSD). However, to date, its mechanism of action remains unclear. Preclinical studies found that (2 R,6 R;2 S,6 S)-hydroxynorketamine (HNK), a major circulating metabolite of ketamine, elicits antidepressant effects similar to those of ketamine. To help determine how (2 R,6 R)-HNK contributes to ketamine's mechanism of action, an exploratory, targeted, metabolomic analysis was carried out on plasma and CSF of nine healthy volunteers receiving a 40-minute ketamine infusion (0.5 mg/kg). A parallel targeted metabolomic analysis in plasma, hippocampus, and hypothalamus was carried out in mice receiving either 10 mg/kg of ketamine, 10 mg/kg of (2 R,6 R)-HNK, or saline. Ketamine and (2 R,6 R)-HNK both affected multiple pathways associated with inflammatory conditions. In addition, several changes were unique to either the healthy human volunteers and/or the mouse arm of the study, indicating that different pathways may be differentially involved in ketamine's effects in mice and humans. Mechanisms of action found to consistently underlie the effects of ketamine and/or (2 R,6 R)-HNK across both the human metabolome in plasma and CSF and the mouse arm of the study included LAT1, IDO1, NAD+, the nitric oxide (NO) signaling pathway, and sphingolipid rheostat.

Sex-dependent metabolism of ketamine and (2R,6R)-hydroxynorketamine in mice and humans

BACKGROUND

Ketamine is rapidly metabolized to norketamine and hydroxynorketamine (HNK) metabolites. In female mice, when compared to males, higher levels of (2R,6R;2S,6S)-HNK have been observed following ketamine treatment, and higher levels of (2R,6R)-HNK following the direct administration of (2R,6R)-HNK.

AIM

The objective of this study was to evaluate the impact of sex in humans and mice, and gonadal hormones in mice on the metabolism of ketamine to form norketamine and HNKs and in the metabolism/elimination of (2R,6R)-HNK.

METHODS

In CD-1 mice, we utilized gonadectomy to evaluate the role of circulating gonadal hormones in mediating sex-dependent differences in ketamine and (2R,6R)-HNK metabolism. In humans (34 with treatment-resistant depression and 23 healthy controls) receiving an antidepressant dose of ketamine (0.5 mg/kg i.v. infusion over 40 min), we evaluated plasma levels of ketamine, norketamine, and HNKs.

RESULTS

In humans, plasma levels of ketamine and norketamine were higher in males than females, while (2R,6R;2S,6S)-HNK levels were not different. Following ketamine administration to mice (10 mg/kg i.p.), C_max and total plasma concentrations of ketamine and norketamine were higher, and those of (2R,6R;2S,6S)-HNK were lower, in intact males compared to females. Direct (2R,6R)-HNK administration (10 mg/kg i.p.) resulted in higher levels of (2R,6R)-HNK in female mice. Ovariectomy did not alter ketamine metabolism in female mice, whereas orchidectomy recapitulated female pharmacokinetic differences in male mice, which was reversed with testosterone replacement.

CONCLUSION

Sex is an important biological variable that influences the metabolism of ketamine and the HNKs, which may contribute to sex differences in therapeutic antidepressant efficacy or side effects.

Cross-Laboratory Standardization of Preclinical Lipidomics Using Differential Mobility Spectrometry and Multiple Reaction Monitoring

Modern biomarker and translational research as well as personalized health care studies rely heavily on powerful omics' technologies, including metabolomics and lipidomics. However, to translate metabolomics and lipidomics discoveries into a high-throughput clinical setting, standardization is of utmost importance. Here, we compared and benchmarked a quantitative lipidomics platform. The employed Lipidyzer platform is based on lipid class separation by means of differential mobility spectrometry with subsequent multiple reaction monitoring. Quantitation is achieved by the use of 54 deuterated internal standards and an automated informatics approach. We investigated the platform performance across nine laboratories using NIST SRM 1950-Metabolites in Frozen Human Plasma, and three NIST Candidate Reference Materials 8231-Frozen Human Plasma Suite for Metabolomics (high triglyceride, diabetic, and African-American plasma). In addition, we comparatively analyzed 59 plasma samples from individuals with familial hypercholesterolemia from a clinical cohort study. We provide evidence that the more practical methyl-tert-butyl ether extraction outperforms the classic Bligh and Dyer approach and compare our results with two previously published ring trials. In summary, we present standardized lipidomics protocols, allowing for the highly reproducible analysis of several hundred human plasma lipids, and present detailed molecular information for potentially disease relevant and ethnicity-related materials.

A brain proteomic signature of incipient Alzheimer's disease in young APOE ε4 carriers identifies novel drug targets

Aptamer-based proteomics revealed differentially abundant proteins in Alzheimer’s disease (AD) brains in the Baltimore Longitudinal Study of Aging and Religious Orders Study (mean age, 89 ± 9 years). A subset of these proteins was also differentially abundant in the brains of young APOE ε4 carriers relative to noncarriers (mean age, 39 ± 6 years). Several of these proteins represent targets of approved and experimental drugs for other indications and were validated using orthogonal methods in independent human brain tissue samples as well as in transgenic AD models. Using cell culture–based phenotypic assays, we showed that drugs targeting the cytokine transducer STAT3 and the Src family tyrosine kinases, YES1 and FYN, rescued molecular phenotypes relevant to AD pathogenesis. Our findings may accelerate the development of effective interventions targeting the earliest molecular triggers of AD.

Ketamine for Refractory Chronic Migraine: An Observational Pilot Study and Metabolite Analysis

Patients with refractory chronic migraine have substantial disability and have failed many acute and preventive medications. When aggressive intravenous therapy is indicated, both lidocaine and (R,S)-ketamine infusions have been used successfully to provide relief. Retrospective studies have shown that both agents may be associated with short-term analgesia. In this prospective, observational pilot study of 6 patients, we compared the effects of lidocaine and (R,S)-ketamine infusions and performed metabolite analyses of (R,S)-ketamine to determine its metabolic profile in this population. One of (R,S)-ketamine's metabolites, (2R,6R)-hydroxynorketamine, has been shown in animal studies to reduce pain, but human studies in patients undergoing continuous (R,S)-ketamine infusions for migraine are lacking. All 6 patients tolerated both infusions well with mild adverse effects. The baseline mean pain rating (0-10 numeric rating scale) decreased from 7.5 ± 2.2 to 4.7 ± 2.8 by end of lidocaine treatment ( P ≤ . 05 ) but increased to 7.0 ± 1.4 by the postdischarge visit at 4 weeks (P > .05 vs baseline). The baseline mean pain rating prior to ketamine treatment was 7.4 ± 1.4, which decreased to 3.7 ± 2.3 by the end of the hospitalization ( P ≤ . 05 ) but increased to 7.2 ± 1.7 by the postdischarge visit at 6 weeks (P > .05 vs baseline). For the primary outcome the change in pain from baseline to end of treatment was greater for ketamine than lidocaine (-3.7 vs -2.8; P ≤ . 05 ), but this has minimal clinical significance. Ketamine metabolite analysis revealed that (2R,6R)-hydroxynorketamine was the predominant metabolite during most of the infusion, consistent with previous studies.

Kynurenines link chronic inflammation to functional decline and physical frailty

Chronic inflammation is associated with physical frailty and functional decline in older adults; however, the molecular mechanisms of this linkage are not understood. A mouse model of chronic inflammation showed reduced motor function and partial denervation at the neuromuscular junction. Metabolomic profiling of these mice and further validation in frail human subjects showed significant dysregulation in the tryptophan degradation pathway, including decreased tryptophan and serotonin, and increased levels of some neurotoxic kynurenines. In humans, kynurenine strongly correlated with age, frailty status, TNF-αR₁ and IL-6, weaker grip strength, and slower walking speed. To study the effects of elevated neurotoxic kynurenines on motor neuronal cell viability and axonal degeneration, we used motor neuronal cells treated with 3-hydroxykynurenine and quinolinic acid and observed neurite degeneration in a dose-dependent manner and potentiation of toxicity between 3-hydroxykynurenine and quinolinic acid. These results suggest that kynurenines mediate neuromuscular dysfunction associated with chronic inflammation and aging.

Tryptophan-related toxic metabolites known as kynurenines are altered with chronic inflammation, which damages nerves in aged and frail mice and humans.

ALTERED TRYPTOPHAN DEGRADATION LINKS CHRONIC INFLAMMATION TO FUNCTIONAL DECLINE & FRAILTY IN MICE AND HUMANS

Chronic inflammation is associated with frailty and functional decline in older adults but the molecular mechanisms of this linkage are not well understood. We sought to examine metabolic and physiologic states associated with aging and frailty by analyzing the composition of metabolites in the blood of a population of community dwelling young, and older adults. Serum inflammatory cytokines and demographic and physiological covariates were collected in a set of community-dwelling adults age 20-97 (n=166). We then used LC/MS technology to profile 121 metabolites from five substance classes. Associations of the cytokines and metabolites with grip strength, walking speed, falls and outcomes were assessed in young, robust, pre-frail and frail participants. Age and frailty status positively correlated with IL6, TNFα, TNFαR1, IL1β (p<0.0001). Analysis of metabolites revealed significant alterations in tryptophan degradation pathway with aging and frailty. Among the top metabolites to correlate with age and frailty status were kynurenine (p<0.0001) and the kynurenine/tryptophan ratio (p<0.0001). The kynurenine/tryptophan ratio also tightly correlated with serum inflammatory cytokines TNFαR1 (p<0.0001) and IL-6 (p<0.0001). Higher kynurenine/tryptophan levels were associated with weaker grip strength and slower walking speed, even after adjusting for age, gender, BMI and blood pressure. Further dissection of the pathway revealed the accumulation of 3-hydroxykynurenine, a cytotoxic and neurotoxic intermediate from the kynurenine pathway, with frailty. The increased levels of cytotoxic and neurotoxic molecules in this pathway may in part explain the link between inflammation and cognitive and physical decline in frailty.

(R)-Ketamine exerts antidepressant actions partly via conversion to (2R,6R)-hydroxynorketamine, while causing adverse effects at sub-anaesthetic doses

BACKGROUND AND PURPOSE

(R)-Ketamine (arketamine) may have utility as a rapidly acting antidepressant. While (R)-ketamine has lower potency than (R,S)-ketamine to inhibit NMDA receptors in vitro, the extent to which (R)-ketamine shares the NMDA receptor-mediated adverse effects of (R,S)-ketamine in vivo has not been fully characterised. Furthermore, (R)-ketamine is metabolised to (2R,6R)-hydroxynorketamine (HNK), which may contribute to its antidepressant-relevant actions.

EXPERIMENTAL APPROACH

Using mice, we compared (R)-ketamine with a deuterated form of the drug (6,6-dideutero-(R)-ketamine, (R)-d2 -ketamine), which hinders its metabolism to (2R,6R)-HNK, in behavioural tests predicting antidepressant responses. We also examined the actions of intracerebroventricularly infused (2R,6R)-HNK. Further, we quantified putative NMDA receptor inhibition-mediated adverse effects of (R)-ketamine.

KEY RESULTS

(R)-d2 -Ketamine was identical to (R)-ketamine in binding to and functionally inhibiting NMDA receptors but hindered (R)-ketamine's metabolism to (2R,6R)-HNK. (R)-Ketamine exerted greater potency than (R)-d2 -ketamine in several antidepressant-sensitive behavioural measures, consistent with a role of (2R,6R)-HNK in the actions of (R)-ketamine. There were dose-dependent sustained antidepressant-relevant actions of (2R,6R)-HNK following intracerebroventricular administration. (R)-Ketamine exerted NMDA receptor inhibition-mediated behaviours similar to (R,S)-ketamine, including locomotor stimulation, conditioned-place preference, prepulse inhibition deficits, and motor incoordination, with approximately half the potency of the racemic drug.

CONCLUSIONS AND IMPLICATIONS

Metabolism of (R)-ketamine to (2R,6R)-HNK increases the potency of (R)-ketamine to exert antidepressant-relevant actions in mice. Adverse effects of (R)-ketamine require higher doses than those necessary for antidepressant-sensitive behavioural changes in mice. However, our data revealing that (R)-ketamine's adverse effects are elicited at sub-anaesthetic doses indicate a potential risk for sensory dissociation and abuse liability.

Assessment of NAD+metabolism in human cell cultures, erythrocytes, cerebrospinal fluid and primate skeletal muscle

The reduction-oxidation state of NAD⁺/NADH is critical for cellular health with NAD⁺ and its metabolites playing critical roles in aging and pathologies. Given the inherent autooxidation of reduced dinucleotides (i.e. NADH/NADPH), and the well-established differential stability, the accurate measurement of NAD⁺ and its metabolites is technically challenging. Moreover, sample processing, normalization and measurement strategies can profoundly alter results. Here we developed a rapid and sensitive liquid chromatography mass spectrometry-based method to quantify the NAD⁺ metabolome with careful consideration of these intrinsic chemical instabilities. Utilizing this method we assess NAD⁺ metabolite stabilities and determine the presence and concentrations of NAD⁺ metabolites in clinically relevant human samples including cerebrospinal fluid, erythrocytes, and primate skeletal muscle.

Mouse, rat, and dog bioavailability and mouse oral antidepressant efficacy of (2R,6R)-hydroxynorketamine

BACKGROUND

(R,S)-ketamine has gained attention for its rapid-acting antidepressant actions in patients with treatment-resistant depression. However, widespread use of ketamine is limited by its side effects, abuse potential, and poor oral bioavailability. The ketamine metabolite, (2R,6R)-hydroxynorketamine, exerts rapid antidepressant effects, without ketamine's adverse effects and abuse potential, in rodents.

METHODS

We evaluated the oral bioavailability of (2R,6R)-hydroxynorketamine in three species (mice, rats, and dogs) and also evaluated five candidate prodrug modifications for their capacity to enhance the oral bioavailability of (2R,6R)-hydroxynorketamine in mice. Oral administration of (2R,6R)-hydroxynorketamine was assessed for adverse behavioral effects and for antidepressant efficacy in the mouse forced-swim and learned helplessness tests.

RESULTS

(2R,6R)-hydroxynorketamine had absolute bioavailability between 46-52% in mice, 42% in rats, and 58% in dogs. Compared to intraperitoneal injection in mice, the relative oral bioavailability of (2R,6R)-hydroxynorketamine was 62%, which was not improved by any of the candidate prodrugs tested. Following oral administration, (2R,6R)-hydroxynorketamine readily penetrated the brain, with brain to plasma ratios between 0.67-1.2 in mice and rats. Oral administration of (2R,6R)-hydroxynorketamine to mice did not alter locomotor activity or precipitate behaviors associated with discomfort, sickness, or stereotypy up to a dose of 450 mg/kg. Oral (2R,6R)-hydroxynorketamine reduced forced-swim test immobility time (15-150 mg/kg) and reversed learned helplessness (50-150 mg/kg) in mice.

CONCLUSIONS

These results demonstrate that (2R,6R)-hydroxynorketamine has favorable oral bioavailability in three species and exhibits antidepressant efficacy following oral administration in mice.

Plasma metabolomic profiling of a ketamine and placebo crossover trial of major depressive disorder and healthy control subjects

(R,S)-Ketamine produces rapid, robust, and sustained antidepressant effects in major depressive disorder. Specifically, its pharmacological efficacy in treatment refractory depression is considered a major breakthrough in the field. However, the mechanism of action of ketamine's rapid effect remains to be determined. In order to identify pathways that are responsible for ketamine's effect, a targeted metabolomic approach was carried out using a double-blind, placebo-controlled crossover design, with infusion order randomized with medication-free patients with treatment-resistant major depressive disorder (29 subjects) and healthy controls (25 subjects). The metabolomic profile of these subjects was characterized at multiple time points, and a comprehensive analysis was investigated between the following: MDD and healthy controls, treatment and placebo in both groups and the corresponding response to ketamine treatment. Ketamine treatment resulted in a general increase in circulating sphingomyelins, levels which were not correlated with response. Ketamine response resulted in more pronounced effects in the kynurenine pathway and the arginine pathway at 4 h post-infusion, where a larger decrease in circulating kynurenine levels and a larger increase in the bioavailability of arginine were observed in responders to ketamine treatment, suggesting possible mechanisms for response to ketamine treatment.

Temporal changes in sphingolipids and systemic insulin sensitivity during the transition from gestation to lactation

Reduced insulin action develops naturally during the peripartum to ensure maternal nutrient delivery to the fetus and neonate. However, increased insulin resistance can facilitate excessive lipolysis which in turn promotes metabolic disease in overweight dairy cattle. Increased fatty acid availability favors the accumulation of the sphingolipid ceramide and is implicated in the pathogenesis of insulin resistance, however, the relationship between sphingolipid metabolism and insulin resistance during the peripartum remains largely unknown. Our objectives were to characterize temporal responses in plasma and tissue sphingolipids in lean and overweight peripartal cows and to establish the relationships between sphingolipid supply and lipolysis, hepatic lipid deposition, and systemic insulin action. Twenty-one multiparous lean and overweight Holstein cows were enrolled in a longitudinal study spanning the transition from gestation to lactation (d -21 to 21, relative to parturition). Plasma, liver, and skeletal muscle samples were obtained, and sphingolipids were profiled using LC/MS/MS. Insulin sensitivity was assessed utilizing intravenous insulin and glucose challenges. Our results demonstrated the following: first, insulin resistance develops postpartum concurrently with increased lipolysis and hepatic lipid accumulation; second, ceramides and glycosylated ceramides accumulate during the transition from gestation to lactation and are further elevated in overweight cows; third, ceramide accrual is associated with lipolysis and liver lipid accumulation, and C16:0- and C24:0-ceramide are inversely associated with systemic insulin sensitivity postpartum; fourth, plasma sphingomyelin, a potential source of ceramides reaches a nadir at parturition and is closely associated with feed intake; fifth, select sphingomyelins are lower in the plasma of overweight cows during the peripartal period. Our results demonstrate that dynamic changes occur in peripartal sphingolipids that are influenced by adiposity, and are associated with the onset of peripartal insulin resistance. These observations are in agreement with a putative potential role for sphingolipids in facilitating the physiological adaptations of peripartum.

Palmitic acid feeding increases ceramide supply in association with increased milk yield, circulating nonesterified fatty acids, and adipose tissue responsiveness to a glucose challenge

Reduced insulin action is a key adaptation that facilitates glucose partitioning to the mammary gland for milk synthesis and enhances adipose tissue lipolysis during early lactation. The progressive recovery of insulin sensitivity as cows advance toward late lactation is accompanied by reductions in circulating nonesterified fatty acids (NEFA) and milk yield. Because palmitic acid can promote insulin resistance in monogastrics through sphingolipid ceramide-dependent mechanisms, palmitic acid (C16:0) feeding may enhance milk production by restoring homeorhetic responses. We hypothesized that feeding C16:0 to mid-lactation cows would enhance ceramide supply and ceramide would be positively associated with milk yield. Twenty multiparous mid-lactation Holstein cows were enrolled in a study consisting of a 5-d covariate, 49-d treatment, and 14-d posttreatment period. All cows were randomly assigned to a sorghum silage-based diet containing no supplemental fat (control; n=10; 138±45 d in milk) or C16:0 at 4% of ration dry matter (PALM; 98% C16:0; n=10; 136±44 d in milk). Blood and milk were collected at routine intervals. Liver and skeletal muscle tissue were biopsied at d 47 of treatment. Intravenous glucose tolerance tests (300mg/kg of body weight) were performed at d -1, 24, and 49 relative to start of treatment. The plasma and tissue concentrations of ceramide and glycosylated ceramide were determined using liquid chromatography coupled with tandem mass spectrometry. Data were analyzed as repeated measures using a mixed model with fixed effects of treatment and time, and milk yield served as a covariate. The PALM treatment increased milk yield, energy-corrected milk, and milk fat yield. The most abundant plasma and tissue sphingolipids detected were C24:0-ceramide, C24:0-monohexosylceramide (GlcCer), and C16:0-lactosylceramide. Plasma concentrations of total ceramide and GlcCer decreased as lactation advanced, and ceramide and GlcCer were elevated in cows fed PALM. Palmitic acid feeding increased hepatic ceramide levels, a response not observed in skeletal muscle tissue. Plasma ceramides (e.g., C24:0-ceramide) were positively correlated with plasma NEFA and milk yield, and positively correlated with NEFA levels following a glucose challenge. Our data demonstrate a remodeled plasma and hepatic sphingolipidome in mid-lactation dairy cows fed PALM. The potential involvement in ceramide in homeorhetic nutrient partitioning to support lactation requires further consideration.

Transport of Mechanically Ventilated Patients in the Prone Position

OBJECTIVE

We present seven cases of patients with severe respiratory failure refractory to conventional ventilation who were safely transported in the prone position.

METHODS

We describe all cases of patients transported by a regional critical care network in the prone position from January 2010-June 2015. All patients were mechanically ventilated for respiratory failure and transported by specialized nonphysician critical care teams. Utilizing direct medical oversight and real-time technical support from the clinical department, each patient underwent a thorough bedside evaluation, transport ventilator trial, and transfer to a transport stretcher either with the endotracheal tube secured by an anesthesia pillow or overhanging the stretcher.

RESULTS

Seven patients with acute respiratory distress syndrome were transported in the prone position. Four were female (57%), with a median weight of 78 kg (range 58-131) and median age of 53 years (range 37-78). Initial vital signs demonstrated a median oxygen saturation of 94% (range 90-97%) supported with a FiO2 of 100% for all patients with a median positive end-expiratory pressure (PEEP) of 16 (range 14-20). Seven patients were transported, six by helicopter and one transported by ground ambulance. The median transport time was 36 minutes (IQR 19, 51). There were no deaths or major incidents (tube dislodgement or line displacement) during patient transport.

CONCLUSION

The transport of mechanically ventilated patients with respiratory failure in the prone position is feasible and safe, with minimal complications identified in this case series.

Dynamics of autochthonous soil viral communities parallels dynamics of host communities under nutrient stimulation

Viruses are highly abundant in soils with their numbers exceeding those of cooccurring bacterial cells by 10- to over 1000-fold. Water and organic matter content influence the magnitude of the viral-to-bacterial ratio in soils; thus, ecosystem type and land use shape interactions between viral and host microbial communities in soils. Less understood are the shorter term interactions between viral and host communities that ultimately maintain the large viral standing stock within soils. This study examined short-term dynamics of viral and bacterial communities in soils to determine whether the growth of soil bacterial communities results in the production of soil viruses, and if viral community responses occur within specific populations. In microcosms amended with different carbon sources, increases in viral abundance (VA) accompanied increases in bacterial abundance (BA) and bacterial respiration rate (BRR). The timing and intensity of increases in BA, VA and BRR were different across C sources suggesting differences in the predominant mode of viral replication within growth-stimulated bacterial populations. Moreover, compositional changes occurred in soil bacterial and viral communities indicating that new viral production arose from a subset of host populations. To our knowledge, these are the first observations of soil viral populations responding to short-term changes in soil bacterial communities.

Clinical agreement between automated and calculated ultrasound measurements of bladder volume

Non-invasive urine volume measurement is an important tool in the management of dysfunctional and neuropathic bladders in children. Ultrasound imaging devices have been used for many years for this purpose. An automated scanner (Bladderscan) is now available and has been recommended by a number of authors, but there is conflicting evidence in the literature regarding the accuracy and appropriate clinical application of the device. We aimed to assess the level of clinical agreement between the two methods. 36 urine volume measurements were made on 11 children using both instruments. Although there was a good correlation between the methods (r=0.97), the clinical agreement was poor (limits of agreement +/-77 ml). 13 voided volumes were directly measured and compared with the difference between pre- and post-void ultrasound measurements. The systematic errors were small but the mean absolute errors were 54 ml and 23 ml, respectively, for the automated and ultrasound imaging methods. If used correctly, ultrasound imaging provides more accurate results and can compete with the cost, convenience and ease of use of the automated method. Low cost, highly portable ultrasound imaging devices are now available and should be used in preference to the Bladderscan.

Breaking bad news--development of a hospital-based training workshop

The skills required to break bad news have been written about extensively and are taught in medical schools. Recent initiatives have concentrated on improving the skills of doctors and nurses in senior positions, who act as role models for their junior colleagues. A multiprofessional learning situation can be a threatening environment, in which colleagues may worry about exposing some of the weaknesses in their knowledge and skills regarding communication with patients. We describe the initiation, running, and evaluation of successful training workshops on breaking bad news in a large British district hospital.

Waiting lists. On a knife edge

Achieving the government's waiting list targets relies heavily on the willingness of theatre staff to do overtime. A survey of acute trusts in England found that more than three-quarters were having difficulty recruiting staff. A third were using local pay incentives, including double time for waiting list initiative work and bonus schemes. Theatre management needs a more strategic approach.

Immune hyperactivation of HIV-1-infected T cells mediated by Tat and the CD28 pathway

Human immunodeficiency virus-type 1 (HIV-1) infection is characterized by a chronic state of immune hyperactivation in patients. Infection of human peripheral blood lymphocytes with HIV-1 in vitro resulted in increased interleukin-2 (IL-2) secretion in response to T cell activation via the CD3 and CD28 receptors. Expression of the HIV-1 transactivator Tat recapitulated this phenotype and was associated with increased IL-2 secretion in response to costimulation with CD3 plus CD28. IL-2 superinduction by Tat occurred at the transcriptional level, was mediated by the CD28-responsive element in the IL-2 promoter, and was exclusively dependent on the 29 amino acids encoded by the second exon of Tat.

Group therapeutic factors on an alcohol in-patient unit

Seventy consecutive patients admitted to an alcohol unit were given a modified version of Yalom's therapeutic factor questionnaire at various points during the therapeutic programme. This programme consists of a two-week introductory programme, followed by a treatment programme, which includes psychodynamic groups, life-history reviews and intensive cognitive-therapy sessions. Internal agreement of ranking order of therapeutic factors was high among all patients and was independent of time spent in group therapy. Patients valued most an existential factor (which embraces concepts of personal responsibility and isolation), self-understanding and cohesiveness; they least valued guidance and identification. Therapists also completed the questionnaire: their ranking of therapeutic factors correlated highly with that of patients, but they ranked an existential factor much lower.

Inguinal herniation justifies sigmoidoscopy

Controversy exists concerning the association of inguinal hernia and colonic carcinoma and, more specifically, whether the development of an inguinal hernia justifies sigmoidoscopy. To study the role of endoscopic screening in cases of inguinal hernia, we prospectively evaluated 464 patients with inguinal hernia over a 54-month period with flexible sigmoidoscopy. Each patient was over the age of 40 and male. Sigmoidoscopy documented polyps (97 patients, 21 percent) and carcinoma (22 patients, 5 percent). Multiple neoplasms were observed in 6 percent (7 of 119 patients). Occult blood was detected in the fecal specimens of 8 percent of the total group of patients, but in only 13 percent of the patients with polyps or carcinomas. A normal examination occurred in only 38 percent of the total group. By using the presence of an inguinal hernia in patients older than 40 years of age as an indication for sigmoidoscopy, we found that more than one of every four patients had an asymptomatic, concurrent malignant or premalignant colonic lesion. Flexible sigmoidoscopy should be used for screening colonic neoplasms in patients with inguinal hernia.

Isolation and identification of Listeria monocytogenes in dairy products

After an outbreak of listeriosis in Massachusetts in 1983, the ability of Listeria monocytogenes to survive in raw and pasteurized milk was investigated. An enrichment broth (EB) containing acriflavine, nalidixic acid, and cycloheximide was used to eliminate overgrowth of the culture by competing organisms, and a modification of McBride's agar (MMA) was used as the isolation medium. The culture was incubated 24 h at 30 degrees C. To isolate Listeria from soft cheese, the incubation period was lengthened to 1 week, and the EB culture was streaked to MMA at 1 and 7 days. Physical and biochemical patterns, the CAMP test, serological tests, and mouse pathogenicity studies were helpful in determining the identity of L. monocytogenes.

Pathogenicity test for Listeria monocytogenes using immunocompromised mice

The lethality of Listeria isolates was determined with normal adult mice and mice that were immunocompromised by treatment with 20 mg of carrageenan per kg. The mean 50% lethal doses (LD50s) of the pathogenic isolates were significantly lower (alpha = 0.05) in the immunocompromised mice than in the untreated mice, with an average reduction of 5.8 log10 units. In contrast, the mean LD50s of the nonpathogenic isolates were lower in the immunocompromised mice by an average of only 0.4 log10 unit, a difference that was not significant (alpha = 0.05). When immunocompromised mice were used, the LD50s of pathogenic Listeria monocytogenes isolates were lower than those of nonpathogenic L. innocua and L. seeligeri isolates by greater than or equal to 6 log10 units and lower than those of nonpathogenic L. ivanovii isolates by greater than or equal to 4 log10 units. Pathogenic L. monocytogenes isolates could be distinguished from nonpathogenic isolates by their ability to cause deaths in immunocompromised mice in 3 days at a dose of approximately 10(4) CFU per mouse. An alternative procedure using iron-overloaded mice failed to effectively differentiate pathogenic Listeria isolates.

Listeria monocytogenes in Raw Milk: Detection, Incidence, and Pathogenicity

To determine the incidence of Listeria monocytogenes in raw milk, an isolation method was evaluated and used to analyze milk from three areas of the United States. The incidence varied by area from 0% in California to 7% in Massachusetts, with an overall incidence of 4.2%. The highest incidence found in any area during a single sampling period was 12% in Massachusetts in March 1985. During that same sampling, the incidence for all Listeria species was 26%. Of the 27 L. monocytogenes strains isolated during the survey, 25 were pathogenic in adult mice. One of three Listeria ivanovii isolated was pathogenic. No other isolates demonstrated pathogenicity.

A comparison of the antidepressant action of citalopram and amitriptyline

The response of patients with major depressive illness to citalopram of amitriptyline was compared in a double-blind multi-centre trial. No differences in efficacy were observed, but citalopram had less hypnotic effect, and a remarkably lower profile of side-effects.

Suppression of post-vasectomy cytotoxic sperm antibody formation in rats by a short-term pretreatment with cyclosporine

The effect of a short pulse therapy with cyclosporine on the production of vasectomy-induced cytotoxic sperm antibodies was studied in Lewis rats. Cyclosporine at a dose of 10 mg/kg was administered once daily for 7 days before and 7 days after vasectomy (group A), for 7 days before vasectomy (group B), and for 7 days after vasectomy (group C). Ten rats were studied in each group for a period of 5 weeks. Ten rats were vasectomized and untreated with cyclosporine (group U). All animals in this group developed high titers of cytotoxic sperm antibodies at the end of the first week after vasectomy (primary antibody response). In contrast, all the treated rats of groups A, B, and C had a normal range of sperm antibody titers. By the third week, six of nine rats in the post-treated group C had significant cytotoxic sperm antibody titers, while the other groups had normal antibody titers. In the fourth week, all the rats of groups A and B continued to have normal sperm antibody titers of less than or equal to 16, while most animals in groups C (78%) and U (63%) had significant cytotoxic sperm antibody titers. It is concluded that prevasectomy treatment with cyclosporine may significantly reduce or delay the production of cytotoxic sperm antibodies in Lewis rats.

Comparison of methods for isolating Campylobacter jejuni from raw milk

The method of Doyle and Roman (Appl. Environ. Microbiol. 43:1343-1353, 1982) was compared with that of Lovett et al. (Appl. Environ. Microbiol. 46:459-462, 1983) for the ability to recover Campylobacter jejuni strains inoculated into raw milk at a concentration of less than 1 cell per g. The method of Lovett et al. gave significantly greater recovery proportions.

Physician attitudes toward confidential care for adolescents

We examined factors that determine whether pediatricians will grant confidential care to adolescents. Through four vignettes, in which adolescents of different ages and maturity requested confidential care, we assessed the willingness of physicians to give such care for four problems: request for contraceptive, diagnosis of gonorrhea, intrauterine device found incidentally on x-ray study, and illicit drug use. A random sample of 932 physicians responded to the vignettes. Overall, physicians agreed to give confidential care to adolescents in 75% of the vignettes. They were more likely to give confidentiality in cases involving sexual activity. They supported confidential care for 87% of patients requesting contraceptives, but for only 54% reporting illicit drug use. The proportion of physicians supporting confidentiality increased with age and maturity of the minors. Seventeen-year-old mature adolescents seeking contraceptives were given confidentiality by 97% of physicians. Thus physician responses to vignettes indicated that they strongly support confidential care for adolescents as represented in the clinical vignettes.

Detection of Escherichia coli enterotoxins by using mouse adrenal cell and suckling mouse assays: collaborative study

The ability of 10 Escherichia coli strains to produce heat-stable enterotoxin (ST) and heat-labile enterotoxin (LT) was determined by 8 analysts in a collaborative study. The suckling mouse model and the mouse adrenal cell line (Y-1) tests were used to detect ST and LT, respectively. Cultures for assay were grown 24 h in casamino acid-yeast extract-trace salts broth at 37 degrees C in a shaker incubator at 250 rpm. Cell-free culture broth prepared by centrifugation and filtration was divided into 2 portions: One was heated for 30 min and used both for ST assay and as a heated control for LT assay; the other was used unheated for LT assay. Results were expressed as positive for ST, positive for LT, positive for ST and LT, or negative for both ST and LT; percent of correct estimates was calculated for each culture for each analyst. At the 95% confidence interval, the overall correct results were 96.3 +/- 2.9 and 95.0 +/- 3.4% for ST and LT, respectively. The test performances thus were satisfactory for detecting ST and LT produced in vitro by E. coli. The method has been adopted official first action.

A comparison of clinical course with blood group antigen testing by specific red cell adherence and immunoperoxidase in ureteral and renal pelvic tumors

Specimens of transitional cell carcinoma of the ureter and renal pelvis from 20 patients were tested for blood group antigenicity using immunoperoxidase and specific red cell adherence methods. The results of antigen testing were correlated with tumor stage and grade as well as the subsequent clinical course of the patients. The specific red cell adherence test was negative in 80 per cent and the immunoperoxidase test was negative in 40 per cent of all tumors. Of the 4 patients with positive specific red cell adherence tests 3 had high grade (II to III), invasive tumors as did 7 of 12 with tumors that were positive by immunoperoxidase testing. Blood group antigen testing did not prove helpful in predicting the clinical course of our patients. In addition, a careful review of previously published data does not support the conclusion that blood group antigen testing is a valuable predictor of upper tract tumor aggressiveness.

Isolation of Campylobacter jejuni from raw milk

Campylobacter jejuni was isolated from raw milk by a method that can routinely detect less than or equal to 1 organism per ml. This procedure was used in a survey of 195 separate farms and showed a 1.5% incidence of C. jejuni in milk from bulk tanks.

Effect of temperature, duration of incubation, and pH of enrichment culture on the recovery of Campylobacter jejuni from eviscerated market chickens

To establish an enrichment system of high efficiency for recovery of Campylobacter jejuni from market chickens, the effects of the temperature, duration of incubation, and pH of the enrichment culture on the isolation of the bacterium were evaluated. Whole chickens or chicken parts in plastic bags were individually rinsed, and the washings filtered through cheesecloth. The cells were separated from the washings by centrifugation, and the pellet was inoculated into 100 mL of enrichment broth. Isolation of C. jejuni from poultry samples was significantly increased by incubating these samples in an enrichment medium at 42 degrees C as opposed to 35 degrees C; for 48 h as opposed to 24 h or 72 h; and at pH 7.0 as opposed to pH 6.0, 6.5, 7.5, or 8.0.

Thermal inactivation of Yersinia enterocolitica in milk

Three strains of Yersinia enterocolitica isolated from milk had D values at 62.8 degrees C from 0.24 to 0.96 min and z values of 5.11 to 5.78 degrees C. Since the pasteurization processes for dairy products recommended by the Food and Drug Administration are adequate to destroy large concentrations of these organisms, Y. enterocolitica in pasteurized milk probably results from substandard processing or recontamination after pasteurization.

Incidence of Campylobacter jejuni in fresh eviscerated whole market chickens

A total of 100 fresh eviscerated whole market chickens, purchased one per week over a 5-week period from each of 20 different food stores in the Ontario and Ohio regions, were examined for the presence of Campylobacter jejuni. The microorganism was recovered from 62 and 54% of the chickens in Ontario and Ohio, respectively.

Enterotoxin production and thermal resistance of Yersinia enterocolitica in milk

Three of 36 raw milk isolates of Yersinia enterocolitica produced enterotoxin in milk at 25 degrees C, but not at 4 degrees C. No strain tested could survive pasteurization.

Travel for primary care: expectation and performance in a rural setting

Data and findings are presented pertaining to the expressed travel limits for general medical care of a rural population and the degree to which their observed travel behavior reflects these limits. Considerable variation in expressed reasonable and maximum travel distances and times was observed among respondents in a countywide cross-section sample of the resident population in western Maine. A substantial proportion of the respondents' visits for general medical care exceeds their reasonable travel limits and some visits exceed the travel limits they considered maximal. Additionally, a comparison of expectations from this study with those of a similar population in another section of the county reveals significant differences. The findings suggest that health planning could be considerably enhanced by a better understanding of patient preferences for medical care travel behavior, the origins of these preferences, and their relationship to the use of available medical care opportunities. This is particularly true if stated goals of incorporating patient preferences into the health planning process are to be realized.

Successful re-treatment with cis-dichlorodiammineplatinum(II) after apparent allergic reactions

Allergic or anaphylactic-like reactions have been reported with cis-dichlorodiammineplatinum(II) (CDDP) administration. We have seen two reactions among 50 patients treated in a phase II trial of CDDP. Both patients were successfully rechallenged after diphenhydramine pretreatment, and therapy was continued. In vivo and in vitro studies performed in one patient included negative skin tests, negative histamine release assay, negative lymphocyte stimulation studies, and normal total serum IgE. We conclude that some apparent allergic reactions occurring with CDDP may have a non-allergic etiology, and treatment may be successfully continued in selected patients.

Patulin Production by Species of Aspergillus and Penicillium at 1.7, 7.2, and 12.8 C

Two strains each of Aspergillus clavatus (NRRL 1980 and ATCC 9599), Penicillium claviforme (NRRL 1001 and 1002), Penicillium expansum (FM 1071 and NRRL 973), and Penicillium patulum (ATCC 24550 and FM 1172); and one strain of Penicillium griseofulvum (NRRL 2300) were inoculated into potato-dextrose broth and incubated at 1.7, 7.2, and 12.8 C for 110, 84, and 55 days, respectively. All cultures grew at all temperatures. Patulin production by P. griseofulvum and P. claviforme , NRRL 1001, was limited or inhibited at 1.7 C, whereas at 7.2 C only P. griseofulvum , NRRL 2300, failed to produce toxin. Patulin was produced at 12.8 C by all nine cultures.

Trimming as a means of removing patulin from fungus-rotted apples

Penicillium expansum 1071, 1172, NRLL 973, and Penicillium patulum ATCC 24550 were inoculated into Red Delicious, Golden Delicious, and McIntosh apples. The decayed tissue was trimmed from the sound tissue, each fraction was weighed, and the patulin concentration in the juice was assayed by thin layer chromatography. The quantity of patulin in the whole apples and in decayed tissues was calculated and these values were used to determine the percentage of total patulin removed by trimming. The patulin content ranged from 140 to 4880 mug/apple. Trimming removed 93-99% of the total patulin, regardless of incubation temperature, fungus strain, or apple variety. Trimming of defective tissue from fungus-rotted apples could substantially reduce the patulin concentration.