Moving towards the ICOPE Approach: Evaluation of Community-Based Intervention Activities on Improving Intrinsic Capacity

OBJECTIVES

Different types of community-based intervention activities may have differential effects in improving the intrinsic capacity (IC) of older people. This study aims to (i) identify subgroups of older people based on their IC impairments, (ii) examine the differential associations between different types of activity participations and change in IC across subgroups, and (iii) assess whether the activity participation patterns of older people align with the way that would benefit them the most.

METHODS

Participants were community-dwelling older people aged 60 years or above. They were screened for IC impairments at baseline, and their participation records of different types (cognitive, physical, nutritional, mental, and social) of intervention activities were collected for one year. An aggregated IC score was created based on four IC domains including cognitive (self-rated memory), locomotor (self-rated difficulties in walking), vitality (self-rated weight loss), and psychological (subjective well-being). Cluster analysis was used to group homogenous participants. Mixed-effects regression was used to examine the associations between activity counts (i.e., number of sessions participated) and change in IC. Activity participation patterns were also compared across subgroups.

RESULTS

Data were obtained from 7,357 participants (mean age = 74.72 years). Four clusters were identified, including those who were relatively robust (cluster 1, N = 4,380, 59.5%), those who had cognitive decline (cluster 2, N = 2,134, 29.0%), those who had impaired mobility and vitality (cluster 3, N = 319, 4.3%), and those with poor psychological well-being (cluster 4, N = 524, 7.1%). Overall, activity count was associated with IC improvement (β = 0.073, 95% CI [0.037, 0.108]). However, as regards the cluster-specific results, different types of activities were associated with IC improvement for different specific clusters. For instance, cognitive activity count was associated with IC improvement only for cluster 2 (β = 0.491, 95% CI [0.258, 0.732]). Notably, none of the activity types were associated with IC improvement for cluster 1. Regarding the activity participation patterns, there were no significant differences across the four clusters (Wilk's Λ = 0.997, F = 1.400, p = .138).

CONCLUSIONS AND IMPLICATIONS

IC improvement depended on the activity types and IC status of older people. In view of this, a people-centred and targeted approach should be adopted to maximize the overall benefits of intervention activities.

Case study of hypertriglyceridemia from COVID-19 Pfizer-BioNTech vaccination in a patient with familial hypercholesteremia

The Pfizer-BioNTech coronavirus disease 2019 (COVID-19) vaccine is the first novel nucleoside-modified messenger ribonucleic acid (modRNA) vaccine to receive Emergency Use Authorization from the Food and Drug Administration in the United States. It is indicated to be used in patients ≥12 years-of-age as of May 25th, 2021, including populations with high atherosclerotic cardiovascular disease (ASCVD) burden. However, little is known about the potential impact this vaccine may have on serum lipoprotein levels in patients with familial hypercholesteremia (FH), who are predisposed to high ASCVD burden due to elevated low-density lipoprotein cholesterol (LDL-C). We present an interesting case where a patient with heterozygous FH (HeFH) and elevated triglycerides (TG)-controlled for years on medication and apheresis-experienced significantly elevated TG, one day after receiving his second Pfizer-BioNTech COVID-19 vaccine dose. It is not known whether this adverse event may be seen in other FH patients and may be worth assessing in such patients to determine the possibility of a rare adverse reaction from a COVID-19 vaccine.

Different mother and daughter manifestations due to very high cholesterol-containing lipoproteins

Familial hypercholesterolemia (FH) is an autosomal codominant genetic disorder associated with defective hepatic uptake of circulating low-density lipoproteins (LDL), which can lead to premature atherosclerotic cardiovascular disease (ASCVD). Evidence suggests elevated lipoprotein(a) (Lp(a)) levels in FH patients may also increase their ASCVD risk. We present a case series of 2 FH patients where a daughter has a higher ASCVD burden than her mother due to the daughter having elevated Lp(a). This underscores the importance of including Lp(a) in cascade lipid screening in FH patients and their first-degree relatives.

Modeling birds on wires

In this paper we introduce a mathematical model to study the group dynamics of birds resting on wires. The model is agent-based and postulates attraction-repulsion forces between the interacting birds: the interactions are "topological", in the sense that they involve a given number of neighbors irrespective of their distance. The model is first mathematically analyzed and then simulated to study its main properties: we observe that the model predicts birds to be more widely spaced near the borders of each group. We compare the results from the model with experimental data, derived from the analysis of pictures of pigeons and starlings taken in New Jersey: two different image elaboration protocols allow us to establish a good agreement with the model and to quantify its main parameters. We also discuss the potential handedness of the birds, by analyzing the group organization features and the group dynamics at the arrival of new birds. Finally, we propose a more refined mathematical model that describes landing and departing birds by suitable stochastic processes.

Flight-Test of a Tactile Situational Awareness System in a Land-based Deck Landing Task

The National Research Council of Canada and Defence Research and Development Canada flight-tested the U.S. Naval Aerospace Medical Research Laboratory's Tactile Situational Awareness System (TSAS) in a dynamic task. The TSAS vest uses small pneumatic actuators or ‘tactors’ to transmit information to the pilot. Eleven pilots used the TSAS to cue horizontal axis performance in a land-based deck landing task flown in the NRC Bell 205 helicopter. Pilots tracked a vertically moving target with and without the TSAS in good and degraded visual conditions. The TSAS effectively cued longitudinal fore/aft drifts and reduced RMS error. It had less effect on lateral positioning error, possibly due to the presence of strong visual cues. Pilot situational awareness during degraded visual environment conditions in high sea states was significantly improved by the TSAS, as measured by the China Lake situational awareness rating scale. No change in workload, as measured by Modified Cooper Harper Workload Scale, was attributable to the TSAS use. The improvements in situational awareness and the reduction in longitudinal error suggest that the TSAS would be beneficial for helicopter ship deck landing.

XMetA, an allosteric monoclonal antibody to the insulin receptor, improves glycaemic control in mice with diet-induced obesity

XMetA, a high-affinity, fully human monoclonal antibody, allosterically binds to and activates the insulin receptor (INSR). Previously, we found that XMetA normalized fasting glucose and glucose tolerance in insulinopenic mice. To determine whether XMetA is also beneficial for reducing hyperglycaemia due to the insulin resistance of obesity, we have now evaluated XMetA in hyperinsulinemic mice with diet-induced obesity. XMetA treatment of these mice normalized fasting glucose for 4 weeks without contributing to weight gain. XMetA also corrected glucose tolerance and improved non-high density lipoprotein cholesterol. These studies indicate, therefore, that monoclonal antibodies that allosterically activate the INSR, such as XMetA, have the potential to be novel agents for the treatment of hyperglycaemia in conditions associated with the insulin resistance of obesity.

Working memory training is associated with lower prefrontal cortex activation in a divergent thinking task

Working memory (WM) training has been shown to lead to improvements in WM capacity and fluid intelligence. Given that divergent thinking loads on WM and fluid intelligence, we tested the hypothesis that WM training would improve performance and moderate neural function in the Alternate Uses Task (AUT)-a classic test of divergent thinking. We tested this hypothesis by administering the AUT in the functional magnetic resonance imaging scanner following a short regimen of WM training (experimental condition), or engagement in a choice reaction time task not expected to engage WM (active control condition). Participants in the experimental group exhibited significant improvement in performance in the WM task as a function of training, as well as a significant gain in fluid intelligence. Although the two groups did not differ in their performance on the AUT, activation was significantly lower in the experimental group in ventrolateral prefrontal and dorsolateral prefrontal cortices-two brain regions known to play dissociable and critical roles in divergent thinking. Furthermore, gain in fluid intelligence mediated the effect of training on brain activation in ventrolateral prefrontal cortex. These results indicate that a short regimen of WM training is associated with lower prefrontal activation-a marker of neural efficiency-in divergent thinking.

Patched1 deletion increases N-Myc protein stability as a mechanism of medulloblastoma initiation and progression

Medulloblastoma tumorigenesis caused by inactivating mutations in the PATCHED1 (PTCH1) gene is initiated by persistently activated Sonic Hedgehog (Shh) signaling in granule neuron precursors (GNPs) during the late stages of cerebellar development. Both normal cerebellar development and Shh-driven medulloblastoma tumorigenesis require N-Myc expression. However, the mechanisms by which N-Myc affects the stages of medulloblastoma initiation and progression are unknown. Here we used a mouse model of Ptch1 heterozygosity and medulloblastoma to show that increased N-Myc expression characterized the earliest selection of focal GNP hyperplasia destined for later tumor progression. Step-wise loss of Ptch1 expression, from tumor initiation to progression, led to incremental increases in N-Myc protein, rather than mRNA, expression. Increased N-Myc resulted in enhanced proliferation and death resistance of perinatal GNPs at tumor initiation. Sequential N-Myc protein phosphorylation at serine-62 and serine-62/threonine-58 characterized the early and late stages of medulloblastoma tumorigenesis, respectively. Shh pathway activation led to increased Myc protein stability and reduced expression of key regulatory factors. Taken together our data identify N-Myc protein stability as the result of loss of Ptch1, which distinguishes normal cerebellar development from medulloblastoma tumorigenesis.

Influence of dietary pattern on the development of overweight in a Chinese population

OBJECTIVE

To examine dietary factors predisposing to overweight and obesity, taking into account age, gender, education level and physical activity.

DESIGN

Longitudinal population study.

SETTING

Community living subjects in Hong Kong.

SUBJECTS

One thousand and ten Chinese subjects participating in a territory wide dietary and cardiovascular risk factor prevalence survey in 1995-1996 were followed up for 5-9 years.

MEASUREMENTS

Body mass index (BMI) was measured. Information was collected on factors predisposing to development of overweight and obesity (age, gender, education level, physical activity, macronutrient intake, Mediterranean diet score and food variety), and the predisposing dietary factors examined, adjusted for other confounding factors, using logistic regression.

RESULTS

The 5-9-year incidence of overweight is 22.6% (BMI > or =23 kg/m2, 95% confidence interval (CI)=15.0-30.1%) or 11.5% (BMI > or =25 kg/m2, 95% CI=7.3-15.7%), and for obesity (BMI >/=30 kg/m2) is 0.6% (95% CI=-0.2-1.4%). The corresponding figures for women were 14.1% (95% CI=8.8-19.5%), 9.7% (95% CI=6.0-13.4%) and 3% (95% CI=1.3-4.8%). After adjusting for confounding factors (age, sex, education and physical activity), increased variety of snack consumption was associated with increased risk of developing overweight (BMI > or =23 kg/m2) in the Hong Kong Chinese population over a 5-9-year period.

CONCLUSION

Increased variety of snack consumption may predispose to weight gain over a 5-9-year period.

Detection of cerebral oxyhaemoglobin changes during vestibular Coriolis cross-coupling stimulation using near infrared spectroscopy

Near infrared spectroscopy (NIRS) has been successful in monitoring cerebral haemodynamics when the subject is immobilized during surgery, and when there is a drastic depletion of blood from the cerebral cortex during positive acceleration. In this study, we monitored subtle changes of cerebral oxygen level using NIRS during vestibular stimulation. For the control conditions, cerebral oxygen status was monitored in six stationary subjects sitting upright, and while they executed head movements in the pitch axis with eyes opened and eyes closed. The experimental conditions involved the subjects making a head movement which required a 45 degrees pitch-down followed by a return to upright head movements 12 s later during yaw rotation (Coriolis cross coupling) at 10 and 20 rotations per minute (rpm) in a random order. Oxyhaemoglobin (O(2)Hb), deoxyhaemoglobin (HHb) and total haemoglobin levels were recorded every 0.5 s from both the parietal and the occipital lobe simultaneously. A significant rotation effect was observed in total Hb level changes from baseline in both regions. Occipital O(2)Hb increased significantly after the head movement with eyes opened at 20 rpm. Our findings appear to be consistent with previous vestibular studies that significant changes in brain blood flow occur during caloric stimulation. NIRS can be used to monitor discrete cortical blood flow changes resulting from vestibular and other forms of stimulation.

The retinoid anticancer signal: mechanisms of target gene regulation

Retinoids induce growth arrest, differentiation, and cell death in many cancer cell types. One factor determining the sensitivity or resistance to the retinoid anticancer signal is the transcriptional response of retinoid-regulated target genes in cancer cells. We used cDNA microarray to identify 31 retinoid-regulated target genes shared by two retinoid-sensitive neuroblastoma cell lines, and then sought to determine the relevance of the target gene responses to the retinoid anticancer signal. The pattern of retinoid responsiveness for six of 13 target genes (RARβ2, CYP26A1, CRBP1, RGS16, DUSP6, EGR1) correlated with phenotypic retinoid sensitivity, across a panel of retinoid-sensitive or -resistant lung and breast cancer cell lines. Retinoid treatment of MYCN transgenic mice bearing neuroblastoma altered the expression of five of nine target genes examined (RARβ2, CYP26A1, CRBP1, DUSP6, PLAT) in neuroblastoma tumour tissue in vivo. In retinoid-sensitive neuroblastoma, lung and breast cancer cell lines, direct inhibition of retinoid-induced RARβ2 expression blocked induction of only one of eight retinoid target genes (CYP26A1). DNA demethylation, histone acetylation, and exogenous overexpression of RARβ2 partially restored retinoid-responsive CYP26A1 expression in RA-resistant MDA-MB-231 breast, but not SK-MES-1 lung, cancer cells. Combined, rather than individual, inhibition of DUSP6 and RGS16 was required to block retinoid-induced growth inhibition in neuroblastoma cells, through phosphorylation of extracellular-signal-regulated kinase. In conclusion, sensitivity to the retinoid anticancer signal is determined in part by the transcriptional response of key retinoid-regulated target genes, such as RARβ2, DUSP6, and RGS16.

Cloning and characterization of the human neural cell adhesion molecule, CNTN4 (alias BIG-2)

We report the isolation and characterization of human contactin 4 (CNTN4), a brain-derived, immunoglobulin superfamily molecule-2 (alias BIG-2) as a candidate gene responsible for the differentiation potential of human neuroblastoma cells. Northern blot analysis showed highest CNTN4 expression in testes, thyroid, small intestine, uterus and brain. Induction of CNTN4 mRNA expression in human neuroblastoma tumor cells treated with retinoic acid correlated with a block in retinoid-induced neuritogenesis. Our findings suggest a role for human contactin 4 protein in the response of neuroblastoma cells to differentiating agents.

High oral prevalence of Candida krusei in leprosy patients in northern Thailand

Although Candida albicans is the most common human yeast pathogen, other Candida species such as C. krusei are now recognized as emerging agents, especially in patients with human immunodeficiency virus (HIV) disease. C. krusei is inherently resistant to the widely used triazole antifungal fluconazole and poses therapeutic problems, especially in systemic candidiasis. In a surveillance study of leprosy patients (with arrested or burnt-out disease) in a leprosarium in northern Thailand, we found a rate of oral carriage of C. krusei (36%) significantly (P < 0.05) higher than that for a healthy control group (10%). Among the Candida-positive patients, 16 of 35 (46%) carried C. krusei, while C. albicans was the second most common isolate (12 of 35 patients; 34%). The corresponding figures for the control group were 2 of 13 (15%) and 6 of 13 (46%), respectively. Studies of the antifungal resistance of the C. krusei isolates from patients indicated that all except one of the isolates were resistant to fluconazole, two isolates were resistant to ketoconazole, and all isolates were sensitive to amphotericin B. Evaluation of their genetic profiles by randomly amplified polymorphic DNA analysis with three different primers and subsequent analysis of the gel profiles by computerized cluster-derived dendrograms revealed that the C. krusei isolates from patients belonged to 10 disparate clusters, despite the origin from a single locale. These nascent findings indicate an alarmingly high prevalence of a Candida species resistant to a widely used antifungal in a part of the world where HIV disease is endemic.

The menstrual cycle and susceptibility to coriolis-induced sickness

Survey studies on motion sickness susceptibility suggest that females tend to report greater severity in illness and higher incidence of vomiting than males. Menstruation is said to be a contributing factor. A recent study suggested that females were least susceptible to seasickness during ovulation in a "round the world" yacht race. Sixteen subjects (18-36 years old) were exposed to Coriolis cross-coupling stimulation in the laboratory. They were tested once during permenstruation (Day 1-5), ovulation (Day 12-15) and premenstruation (Day 24-28), based on a normalized 28-day cycle, in a randomised design. Physiological measurements of motion sickness included forearm and calf cutaneous blood flow. Subjective evaluation of sickness symptoms was based on Graybiel's diagnostic criteria and Golding's rating method. Our results indicated that under controlled laboratory conditions, different phases of the menstrual cycle appear to have no influence on subjective symptoms of motion sickness or on cutaneous blood flow increase in the forearm and calf. The lack of commonality between the types and levels of hormones that are released during motion sickness and those that are involved in different menstrual phases appears to support our findings.

Pre-existing pulmonary thromboembolic disease in passengers with the "economy class syndrome"

BACKGROUND

Pulmonary emboli, which have occurred in association with air travel, in the past have been thought to have arisen from deep venous thromboses (DVT) which formed during the flight.

HYPOTHESIS

This study was performed to test the idea that not all pulmonary emboli which occur following air travel are the result of inflight DVT formation.

METHODS

Fourteen cases of fatal "economy class syndrome" were examined histologically to determine the age of the fatal thromboemboli.

RESULTS

In 5 of the cases, evidence of pre-existing pulmonary thromboembolic disease was present and in 4 of these cases the fatal thromboemboli observed in the lung tissue pre-dated the flight. Fresh perimortem thrombus without evidence of organization or hemosiderin deposition was observed in 9 cases.

CONCLUSIONS

The commonly held pathological mechanism that the conditions of the flight lead to DVT formation and subsequent pulmonary embolism are not applicable in all cases of "economy class syndrome" and thus other pathophysiological mechanisms must be entertained.

G-transition effects and their implications

G-transition effects are defined as the spectrum of physiological and psychophysical effects induced by rapid changes in gravitoinertial forces, alternating between hypogravity (<1 Gz) and hypergravity (>1 Gz) and vice versa. They appear to involve the cardiovascular and spatial orientation systems. This note attempts to briefly review past and current research efforts on the consequences of G-transitions and to examine potential confounding Coriolis-induced bias in both ground-based and inflight research. A brief review of current evidence of vestibular influence on orthostatic compensation and their implications for G tolerance is presented. The effects of roll-induced hypogravity on subsequent G tolerance and possible misperception of attitude during roll rotation are discussed. An integrated approach is recommended for future research on acceleration and disorientation.

Coriolis-induced cutaneous blood flow increase in the forearm and calf

Using venous occlusion plethysmography, Sunahara et al. reported that Coriolis-induced nausea was accompanied by an increase in forearm blood flow, suggesting a decrease in sympathetic activity to this vascular bed. No significant blood pressure and heart rate changes were observed. Vasodilation of the limbs theoretically impairs orthostatic tolerance, particularly if blood flow is shown to increase simultaneously in the lower limbs. This study examined the latter possibility. Seventeen subjects were exposed to the Coriolis cross-coupling effects induced by 20 RPM yaw rotation, and a simultaneous 45 degrees pitch forward head movement in the sagittal plane every 12 s. Forearm and calf skin blood flow were monitored in real-time using laser Doppler flowmetry (PeriFlux 4001). Our results indicated a significant (p < 0.001) simultaneous forearm and calf skin blood flow increase as a result of Coriolis cross-coupling across all 15 susceptible subjects. No significant changes in blood pressure and heart rate were observed. Coriolis-induced cardiovascular changes may confound previous reports on reduced G tolerance using ground-based centrifuges that invariably evoke cross-coupling effects.

Modulation of A beta deposition in APP transgenic mice by an apolipoprotein E null background

Several lines of evidence implicate apolipoprotein E (apoE) and its receptor--the low density lipoprotein receptor related protein (LRP)--in Alzheimer's disease (AD) pathogenesis, including increased amyloid deposition in human AD brains of people containing the apoE epsilon 4 allele, presence of apoE and LRP in amyloid plaques, and in vitro uptake of amyloid precursor protein (APP) and amyloid beta protein (A beta) by LRP. Studies of crosses of apoE knockout mice with APP transgenic mice support a complex interaction between apoE and A beta deposition. In the Tg2576 mice expressing human APPK670N-M671L, apoE determines the amount, morphology, vascular pattern, and neuropil response to A beta deposits. In the PDAPP mice expressing human APPV717F, apoE also affects the anatomical localization of cerebral A beta deposits. Thus, APP transgenic mice can serve as models to investigate genetic influences on the amount and timing of cerebral amyloidosis, the morphology of amyloid plaques, and the vulnerability of specific neuroanatomical regions to A beta deposition.

Underwater disorientation as induced by two helicopter ditching devices

BACKGROUND

Spatial orientation is based on the integration of concordant and redundant information from the visual, vestibular, and somatosensory systems. When a person is submerged underwater, somatosensory cues are reduced, and vestibular cues are ambiguous with respect to upright or inverted position. Visual cues may be lost as a result of reduced ambient light. Underwater disorientation has been cited as one of the major factors that could inhibit emergency egress after a helicopter ditching into water. One countermeasure to familiarize aircrew with underwater disorientation is emergency egress training. This study examined the relative degree of underwater disorientation induced by the Modular Egress Training Simulator (METS) and the Shallow Water Egress Trainer (SWET).

METHODS

There were 36 healthy subjects (28 males and 8 females) who participated in the study. Underwater disorientation was quantified by measuring the deviation of subjective vertical-pointing from the gravitational vertical, time to egress, and subjective reports of disorientation and ease of egress. A repeated measure design was employed with seat position (SWET chair, METS window, and METS aisle) as the sole factor.

RESULTS

Subjective response data indicated that the degree of disorientation is rated significantly higher, and the ease of egress is rated worse from the two METS seat positions than from the SWET. This is supported by the findings that subjective vertical-pointing accuracy is worse in the METS seat positions than in the SWET (p < 0.01). The time to egress is longer from the two METS seat positions than from SWET (p < 0.01).

CONCLUSION

Our results indicate that the METS device is effective for inducing underwater disorientation as provoked by simulated helicopter ditching. disorientation, vestibular, subjective pointing.

Metabolism of chloramphenicol succinate in human bone marrow

OBJECTIVE/METHODS

The metabolism of chloramphenicol succinate (CAPS) by human bone marrow was studied in vitro using 75 marrow samples. Whole marrow samples were incubated with CAPS with or without reduced nicotinamide adenine dinucleotide phosphate for 1, 2 and 3 h at 37 degrees C. Ficoll-paque-separated marrow mononuclear cells and erythrocytes were similarly incubated. After precipitation and centrifugation, clear supernatant was analysed for the presence of metabolites using high-performance liquid chromatography.

RESULTS

Only one metabolite was detected when CAPS was incubated for 3 h with whole marrow from 72 donors. Its retention time (RT 10.9 min) corresponded to chloramphenicol (CAP). When CAPS was incubated with samples of whole marrow, marrow mononuclear cells, marrow erythrocytes, marrow plasma and peripheral blood from one donor who had taken Traditional Chinese Medicine (TCM), three metabolite peaks were detected within 15 min to 1 h. The RT of two of these peaks corresponded to CAP and nitroso-CAP (RT 14.9 min), but one peak remained unidentified. These peaks were not detected in the control samples incubated without CAPS. Blood samples collected after 3 months and 6 months to reconfirm metabolic activity yielded no such metabolite peaks when incubated with CAPS for 1-3 h. Therefore induction of enzyme activity by TCM was suspected. Three metabolite peaks with the same RTs were also detected when CAPS was incubated for 3 h with whole marrow from two other donors.

CONCLUSION

These studies demonstrated that CAPS may be metabolised to CAP and occasionally other metabolites in human bone marrow. This novel observation is particularly important because the bone marrow is known to be a target organ for chloramphenicol toxicity.

Release from masking in virtual auditory space during sustained positive acceleration

BACKGROUND

The use of a three-dimensional (3-D) auditory display to significantly lower subject detection level while maintaining comprehension under sustained positive G-stress was explored in this study.

METHODS

Auditory threshold levels were measured for detecting a band limited pulsed signal in the presence of a broadband diotic masker at both + 1 Gz (rest position) and under sustained +3 Gz. The pulsed signal was presented diotically and was spatialized at one of four static azimuth positions on the horizontal plane.

RESULTS

Results showed that auditory thresholds were not significantly affected by sustained +3 Gz stress. Compared with a diotic presentation, subjects reached an average of 6.8 dB lower auditory threshold at +1 Gz and under sustained +3 Gz when the pulsed signal was spatialized at a static position of 90 degrees azimuth on the horizontal plane.

CONCLUSION

The implication of these results and suggestions for further research are discussed.

The effects of roll vs. pitch rotation in humans under orthostatic stress

BACKGROUND

It has been known since 1953 that pre-exposure to less than +1 Gz will reduce subsequent +Gz-tolerance. With few exceptions, during operational flying, the transition from hypogravity to hypergravity involves roll as well as pitch rotation. We examined the effect of roll vs. pitch rotation while undergoing transition from hypogravity to +1 Gz on a tilt table.

METHODS

Twelve subjects (28-47 yr old) were rotated at 45 degrees x s(-1) from head-up (HU) at 15 degrees relative to gravitational vertical to 135 degrees head-down (HD) and back to the HU position after different HD dwell times. HD dwell times were set at 7, 15, and 30 s. The subject was rotated about the interaural axis (pitch) and about the naso-occipital axis (roll). Both the HD dwell times and axes of rotation were randomized within and across subjects. BP and heart rate were recorded during the HU-HD-HU maneuver.

RESULTS

Analysis of variance, repeated measure design revealed that the rate and magnitude of BP decrease induced by the HD to HU maneuver is significantly higher (p < 0.01) in roll than in pitch during all HD dwell times. The decrease of BP at 7s is significantly (p < 0.01) higher than at 15s and 30s. Heart rate increases significantly higher (p < 0.01) in pitch than in roll at 7s-dwell time.

CONCLUSION

Our results suggest that the compensatory mechanism to orthostatic stress is more efficient in response to pitch than roll rotation. This is reflected from the findings that the mean magnitude of OH (orthostatic hypotension) and the rate of BP decrease induced by the HD-HU maneuver is significantly greater in roll rotation than pitch rotation. The mean HR increase post HD-HU rotation is significantly higher in the pitch than the roll rotation. The significant rate of BP decrease during HD-HU roll rotation could have important implications for maintaining G-tolerance and spatial orientation during subsequent exposure to hypergravity.

Acute bereavement care in the emergency department: does the professional-supported volunteers model work?

The aims of our study were to study the early impact of bereavement and to evaluate the effectiveness of the bereavement care given by our multidisciplinary team to close relatives of a sudden death, measured by the intensity of grief reaction (Texas Revised Inventory of Grief). The study sample consisted of close relatives of patients certified dead at the accident and emergency department (AED) between March 1996 and February 1997. The relatives received immediate care at the AED and were supported continually by the members of the bereavement care team. The control sample (without acute bereavement care) consisted of close relatives contacted by the liaison nursing officer in the previous year. The intensity of grief reactions were assessed by the volunteer grief counsellors at 6 months. The mean score of the intensity of grief reactions were 41.8 and 34.6 in the control (n = 11) and study (n = 18) groups respectively among high risk sample (p = 0.04). However, in the low risk sample, the mean scores were 35.3 and 30.2 in the control (n = 18) and study (n = 25) groups respectively (p = 0.11). Our study suggests that the bereavement care was especially effective in reducing the intensity of the grief at 6 months in the high risk group.

Degradation of visual pursuit during sustained +3 Gz acceleration

BACKGROUND

During positive acceleration, there is a diminished flow of blood to all regions above the heart. This is manifested by the commonly described loss of peripheral vision, greyout and blackout, which have been investigated extensively. The ability to select appropriate scanning patterns and to efficiently process visual information is one of the important determinants of scan effectiveness. This study investigates the performance of the smooth pursuit system under sustained +3 Gz before any signs of loss of vision.

METHODS

Eleven subjects with no known oculomotor and vestibular anomalies participated in the study. Horizontal and vertical pursuit at amplitudes of 10 and 20 degrees were investigated in each of the subjects over 4 separate days. During each test session, pursuit targets of a predictable sine wave, oscillating at 0.2, 0.4, 0.8, 1.2 and 1.6 Hz were presented to the subjects in a random order. Horizontal and vertical eye movements were recorded using the El-Mar eye tracking system. The subjects were tested in 4 trials: 1) at 1 G before exposure to increased acceleration; 2) during sustained +3 Gz; 3) immediately after the +3 Gz exposure; and 4) 5 min after the +3 Gz exposure.

RESULTS

Breakdown in smooth pursuit in response to horizontal and vertical sinusoidal stimuli during +3 Gz is indicated by a statistically significant decrease in gain and an increase in phase lag (p < 0.01). This is most obvious when the stimulus frequency is greater than 0.4 Hz. Qualitatively, the pursuit response during acceleration was ataxic and disorganized in appearance.

CONCLUSION

It is postulated that degradation of pursuit gain and phase could be due to central hypoxia, and that the increase of G loading on the vestibular system could affect the neural integration of the pursuit signal in the vestibular nuclei with its direct output to the oculomotor system.

Evolution of class I alcohol dehydrogenase genes in catarrhine primates: gene conversion, substitution rates, and gene regulation

The three class I alcohol dehydrogenases (ADHs) in humans comprise homo- and heterodimers of three subunits (alpha, beta, and gamma) with greater than 90% sequence identity. These are encoded by distinct genes (ADH1, ADH2, and ADH3, respectively) and are all expressed in the liver. In baboons, only the beta ADH subunit is expressed in liver. A second class I ADH is expressed in the kidney; we isolated, cloned, and sequenced the cDNA corresponding to this ADH and conclude that it is of the gamma ADH lineage. We also amplified and sequenced the 5' noncoding regions of all three class I baboon ADH genes and the rhesus monkey ADH1 gene and compared their nucleotide sequences with the corresponding human sequences. There is clear evidence that the evolution of these genes has been reticulate. At least three gene conversion events, affecting the coding and 3' noncoding regions of the genes, are inferred from compatibility and partition matrices and phylogenetic analysis of the sequences. Our estimation of the evolutionary history of these genes provides a framework for the investigation of relative substitution rates and functional variation among the sequences. Relative-rate tests, designed to account for the reticulate evolution of these genes, indicate no difference in substitution rate either between genes encoding different subunits or between human and Old World monkey lineages. The human and baboon gamma ADH sequences do not show clear differences at functionally important sites within the coding region, but they do differ at a number of sites in regions previously proposed to be regulatory sites for transcriptional control. This variation may explain the different patterns of gene expression in humans and baboons.

Perspectives of electrogastrography and motion sickness

Electrogastrography (EGG) is a noninvasive measurement of stomach activity using surface electrodes positioned over the abdominal surface. For over 10 years, EGG has been used as an objective measure of epigastric symptoms and nausea experienced in visually induced sickness provoked by circularvection. It was reported that during sickness, there is a shift in the dominant basal electrical activity. The 3 cycles per minute activity decrease and the 4-9 cycles per minute activity increase. This technique has also been used to evaluate the efficacy of antimotion sickness drugs and to monitor sickness induced by other provocative stimuli such as Coriolis cross-coupling, parabolic flight manoeuvres and microgravity. It has been further postulated that peripheral changes in gastric myoelectrical activity in response to visually induced sickness are detected centrally and lead to the generation of motion sickness. However, other studies using either identical or equally effective motion stimuli failed to support the positive correlation of changes in gastric activity with the incidence and severity of motion sickness. The interpretation of spectral analysis on EGG during motion sickness must be taken with great caution. The inherent variability of the EGG and intersubject variability makes it difficult to consider EGG a reliable and robust indicator of motion sickness. Its relation to motion sickness and the underlying mechanism remains unclear. The true diagnostic value of EGG in motion sickness has yet to be determined.

Favorable prognostic significance of high-level retinoic acid receptor beta expression in neuroblastoma mediated by effects on cell cycle regulation

We have previously shown that ectopic overexpression of retinoic acid receptor (RAR) subtypes alpha, beta and gamma in human neuroblastoma cells had different effects on growth and retinoid sensitivity. Only overexpressed RAR beta induced profound growth inhibition in the absence of additional retinoid, and increased retinoid sensitivity. In this study, we measured mRNA expression levels of RAR alpha, beta, and gamma in 50 primary neuroblastoma tumor samples, and found a strong correlation between favorable patient prognosis and high-level RAR beta expression. Human neuroblastoma cells transfected with a vector expressing RAR beta demonstrated irreversible growth arrest following a 1 week exposure to all-transretinoic acid, whereas control cells continued to proliferate. In the absence of additional retinoid, RAR beta transfectants demonstrated a higher proportion of cells in the G0/G1 phase of the cell cycle, increased p21WAF1/CIP1 expression and specific binding to a retinoic acid response element. These were changes which we also observed in control neuroblastoma cells following retinoid treatment. Our data indicate that RAR beta is an important factor mediating the growth inhibitory effects of retinoids in neuroblastoma cells. The favorable effect of high-level RAR beta expression on prognosis in primary tumor tissue may occur through RAR beta effects on p21 expression and consequent G0/G1 cell cycle arrest.

In vitro effects of MYCN sense and antisense expression in MYCN-amplified human neuroblastoma cells

Amplification of the MYCN oncogene is a strong predictor of treatment failure and chemo-resistance in childhood neuroblastoma. Stable expression of two partial MYCN gene fragments in antisense orientation reduced Mycn protein expression in an MYCN-amplified neuroblastoma tumor cell line, however, antisense cells did not exhibit an increased in vitro sensitivity to cytotoxic or differentiating agents. In contrast, partial MYCN sense transfectants exhibited increased resistance to cytotoxic drugs. These data suggest that the chemo-resistance of MYCN-amplified neuroblastoma cells is complex, and may be due to factors additional to Mycn protein expression.

Karaoke therapy in the rehabilitation of mental patients

OBJECTIVES

To study the efficacy of karaoke singing and its implications in the rehabilitation of mental patients in Hong Kong Chinese.

METHODS

A double blind controlled trial was conducted over six weeks in a small sample of chronic schizophrenic patients matched in age, sex and duration of illness. The index group practised karaoke and the controlled group practised simple singing. Subjects were assessed in changes in mood and social interaction.

RESULTS

No significant difference was detectable within the 2 groups. However, significant differences of anxiety and social interaction at the end of the third and sixth weeks respectively, were detectable between the 2 groups.

CONCLUSION

Karaoke therapy may be more effective than simple singing in improving social interaction. There is preliminary evidence that it may be anxiety-provoking for unstable schizophrenic patients. More research is required for further elucidation of the characteristics of favourable candidates, optimal schedule and active components of the therapy.

Oculomotor response to linear acceleration as induced by counter-rotation in supine subjects

BACKGROUND

Horizontal nystagmus occurs in response to sinusoidal linear accelerations directed along an upright subject's Y (interaural) axis, and is proposed to be mediated by an utricular otolith mechanism.

HYPOTHESIS

The otolith organs, composed of the utricles and saccules, provide a unique set of signals for any linear acceleration in 3-dimensional space. A supine subject under alternate changing directions of linear acceleration as induced by counter-rotation will receive alternate stimulation along the Y as well as the Z (dorsoventral) axis. We hypothesized that alternate horizontal and vertical nystagmus would be elicited as a result of the changing direction of linear acceleration.

METHODS

A group of eight subjects in the supine position were exposed to counter-rotation at 0.16, 0.25, and 0.33 Hz. Vertical and horizontal eye movements were recorded simultaneously using the El-Mar eye and head tracking system.

RESULTS

Horizontal nystagmus was observed in all supine subjects. The direction of the slow phase of nystagmus changed with directional changes in linear acceleration. Reversals in the direction of eye movements lagged behind the reversals in the direction of the acceleration. However, only two subjects exhibited alternating horizontal and vertical nystagmus as a result of changing axis of linear acceleration, from "along the Y axis" to "along the Z axis."

CONCLUSION

We propose that the nystagmus induced in the supine subject was provoked by linear acceleration and largely an otolith-mediated reflex. The lack of vertical response could be due to the relative paucity of vestibular afferents information along the dorsoventral axis.

Intravenous and oral pharmacokinetic evaluation of a 2-hydroxypropyl-beta-cyclodextrin-based formulation of carbamazepine in the dog: comparison with commercially available tablets and suspensions

Complexation of carbamazepine with 2-hydroxypropyl-beta-cyclodextrin was performed to provide improved formulations of this widely used antiepileptic drug. Based on this approach, liquid dosage forms were configured for both parenteral and oral use. Intravenous administration of an aqueous carbamazepine x 2-hydroxypropyl-beta-cyclodextrin (CBZ x HPbetaCD) complex at a CBZ dose of 20 mg/kg was well tolerated and generated high initial drug levels that fell monoexponentially as a function of time, yielding a plasma elimination half-life of 38 min. Oral studies were completed with three preparations: a commercially available tablet and suspension, as well as a CBZ x HPbetaCD oral solution. Oral administration of tablets gave erratic and slow absorption, leading to maximum CBZ concentrations (C(max)) of <2 microg/mL, which were manifested only at 2.5 h after drug dosing. The absolute bioavailability of CBZ from the tablets was approximately 25%. Both the suspension and CBZ x HPbetaCD solution gave a significantly improved profile. Thus, the liquid oral dosage forms approximately doubled the oral bioavailability of CBZ compared with the tablets.

Elevated plasma levels of human adrenomedullin in cardiovascular, respiratory, hepatic and renal disorders

1. Adrenomedullin is a potent vasodilating peptide first isolated from phaeochromocytoma and adrenal medulla but also found in the heart, lungs and kidneys. It may also be a paracrine factor because endothelial and smooth muscle cells synthesize adrenomedullin as well as express the receptors. Adrenomedullin induces vasorelaxation by activating adenylate cyclase and also by stimulating the release of nitric oxide. 2. We have developed a specific radioimmunoassay and measured the immunoreactivity of human adrenomedullin in the plasma of 58 male subjects: eight with essential hypertension, 12 with heart failure, 10 with ascites due to cirrhosis, 12 with chronic renal failure, four with hypoxia due to chronic obstructive pulmonary disease and 12 control subjects. 3. Plasma levels (mean +/- SEM) in patients with essential hypertension (16.3 +/- 1.9 pmol/l), congestive heart failure (17.5 +/- 2.8 pmol/l) and renal failure (17.7 +/- 2.5 pmol/l) were raised compared with control subjects (7.8 +/- 1.4 pmol/l, P < 0.05), confirming previous reports. 4. In addition, we observed that plasma levels of adrenomedullin were significantly raised in patients with ascites due to liver cirrhosis (15.5 +/- 1.9 pmol/l) and chronic obstructive pulmonary disease with hypoxia (20.0 +/- 1.5 pmol/l). 5. We concluded that the plasma level of adrenomedullin is raised in a variety of diseases.

Retinoic acid receptors beta and gamma distinguish retinoid signals for growth inhibition and neuritogenesis in human neuroblastoma cells

Retinoids induce marked growth inhibition and neuritic differentiation in human neuroblastoma cells. Expression patterns of nuclear retinoic acid receptors (RAR) in embryonic and adult tissues suggests that RAR subtypes alpha, beta and gamma have tissue-specific functions. We have transfected a human neuroblastoma tumor cell line with a vector expressing either human RAR alpha, beta or gamma cDNAs. In the absence of exogenous retinoid, RAR beta transfectants demonstrated marked growth inhibition without morphologic evidence of differentiation, whereas transfectant clones overexpressing RARs alpha and gamma had no significant reduction in cell growth rates. Although RAR gamma transfectants were sensitive to the growth inhibitory effects of exogenous retinoids, these cells demonstrated resistance to the neuritogenic retinoid effects. Only RAR beta transfectants exhibited increased sensitivity to retinoids added in vitro. These results suggest that distinct neuritogenic and growth inhibitory signalling pathways exist in neuroblastoma cells and that RAR beta expression may be necessary for the retinoid growth inhibitory pathway.

Visual influence on head shaking using the vestibular autorotation test

In this study we investigated the vestibular system by recording eye movements in response to voluntary high-frequency head-only movements using the Vestibular Autorotation Test (VAT; Western System Research Inc., Los Angeles, California). Our objective was to evaluate if the VAT could be implemented as one of the screening tests for vestibular integrity in aircrews and potential pilots. We attempted to record horizontal and vertical eye movements using electrooculography and head velocity with calibrated rotational velocity sensors. The gain and phase of the input and output signals were computed by discrete Fourier analysis. Seated subjects were instructed to fixate on a real or imaginary target while making smooth head oscillations about the spinal axis in time to an audible cue from 0.5 to 6.0 Hz/during an 18-second test period. Test trials included two conditions in the light with subjects fixated on a real target (C1) or on an imaginary target on a blank screen (C2); three conditions in the dark in which subjects fixated on an imaginary target (C3), fixated on a remembered LED target in the dark after it was extinguished (C4), or fixated on a real target (C5). All the dark trials were performed after dark adaptation for 30 minutes. We were not able to obtain consistent vertical VOR response (when the subjects oscillated their head about the interaural axis) using the VAT. For horizontal eye movements from 2.0 to just over 4.7 Hz, when subjects fixated on an imaginary target, there was an unexpected and significant increase in the gain of the eye movement velocities in the dark as compared to the gain obtained in the light conditions. In the dark trials, the gain was significantly higher when the subjects fixated on an imaginary target as opposed to a real target. There was no difference in phase among all conditions. This test could potentially serve for preliminary screening for the integrity of the vestibular system as it is noninvasive and of short duration. However, caution must be exercised in controlling various variables. Extensive normative data are needed to properly assess this test as a screening tool for aircrews.

Evaluation of an intravenous heparin nomogram in a coronary care unit

OBJECTIVE

To develop, implement and evaluate an effective and efficient heparin nomogram.

DESIGN

Retrospective and prospective data collection.

SETTING

Coronary care unit (CCU) of a university-affiliated hospital.

PATIENTS

Patients with acute coronary ischemic syndromes requiring intravenous (i.v.) heparin who were not receiving thrombolytic and/or warfarin therapy.

INTERVENTIONS

A retrospective chart review of 52 CCU patients receiving iv heparin provided the historical control group. The effectiveness of a heparin nomogram (5000 U bolus followed by an initial weight-based infusion of 15 U/kg/h with subsequent rate adjustments according to activated partial thromboplastin time [aPTT] results) was then prospectively assessed in a further 56 consecutive patients.

MAIN RESULTS

The historical control and nomogram groups did not significantly differ with respect to age, weight, duration of therapy or total number of aPTTs drawn. Approximately 79% and 84% of patients in the control and nomogram groups, respectively, achieved an aPTT within the therapeutic range (60 to 90 s, P > 0.05), whereas 89% and 100% of control and nomogram patients, respectively, surpassed the therapeutic threshold (longer than 60 s) at some point during treatment (P = 0.009). Compared with empiric dose adjustment, the nomogram more effectively avoided periods of inadequate anticoagulation. Similarly, the time to achieve the therapeutic threshold was significantly longer in the control than in the nomogram group (8.2 +/- 5.9 versus 6.7 +/- 3.7 h, P = 0.026). No adverse bleeding events were noted in either group.

CONCLUSIONS

Compared with conventional approaches, the heparin nomogram successfully achieved and maintained adequate anticoagulation in a greater proportion of patients with acute cardiovascular diseases without the need for additional aPTT measurements.

A case of unrelenting pursuit of castration

OBJECTIVE

Explore the limitations of the classification of body dysmorphic disorder.

CLINICAL PICTURE

A chinese male relentlessly pursued castration to relieve painful erections which were never substantiated. The testes and corporaspongiosum had been removed. No psychotic symptom was prominent.

TREATMENT

Cognitive therapy and psychotropics were tried.

OUTCOME

The remaining corpora cavernosa was removed subsequently.

CONCLUSION

The distorted somatic perception and secondary cognitive amplification (painful erections) could represent a variant of body dysmorphic disorder involving internal body image; diagnostic classifications should accommodate such a category.