OBJECTIVE--To evaluate the prevention of respiratory complications after abdominal surgery by a comparison of a global policy of incentive spirometry with a regimen consisting of deep breathing exercises for low risk patients and incentive spirometry plus physiotherapy for high risk patients. DESIGN--Stratified randomised trial. SETTING--General surgical service of an urban teaching hospital. PATIENTS--456 patients undergoing abdominal surgery. Patients less than 60 years of age with an American Society of Anesthesia classification of 1 were considered to be at low risk. OUTCOME MEASURES--Respiratory complications were defined as clinical features consistent with collapse or consolidation, a temperature above 38 degrees C, plus either confirmatory chest radiology or positive results on sputum microbiology. We also recorded the time that staff devoted to prophylactic respiratory therapy. RESULTS--There was good baseline equivalence between the groups. The incidence of respiratory complications was 15% (35/231) for patients in the incentive spirometry group and 12% (28/225) for patients in the mixed therapy group (P = 0.40; 95% confidence interval -3.6% to 9.0%). It required similar amounts of staff time to provide incentive spirometry and deep breathing exercises for low risk patients. The inclusion of physiotherapy for high risk patients, however, resulted in the utilisation of an extra 30 minutes of staff time per patient. CONCLUSIONS--When the use of resources is taken into account, the most efficient regimen of prophylaxis against respiratory complications after abdominal surgery is deep breathing exercises for low risk patients and incentive spirometry for high risk patients.

Summary

Background

In low-income countries, surgical site infections (SSIs) are a very frequent form of hospital-acquired infection. Surveillance is an important method for controlling SSI but it is unclear how this can best be performed in low-income settings.

Aim

To examine the epidemiological characteristics of various components of an SSI surveillance programme in a single Kenyan hospital.

Methods

The study assessed the inter-observer consistency of the surgical wound class (SWC) and American Society of Anesthesiologists (ASA) scores using the kappa statistic. Post-discharge telephone calls were evaluated against an outpatient clinician review ‘gold standard’. The predictive value of components of the Centers for Disease Control and Prevention – National Healthcare Safety Network (CDC-NHNS) risk index was examined in patients having major obstetric or gynaecological surgery (O&G) between August 2010 and February 2011.

Findings

After appropriate training, surgeons and anaesthetists were found to be consistent in their use of the SWC and ASA scores respectively. Telephone calls were found to have a sensitivity of 70% [95% confidence interval (CI): 47–87] and a specificity of 100% (95% CI: 95–100) for detection of post-discharge SSI in this setting. In 954 patients undergoing major O&G operations, the SWC score was the only parameter in the CDC-NHNS risk index model associated with the risk of SSI (odds ratio: 4.00; 95% CI: 1.21–13.2; P = 0.02).

Conclusions

Surveillance for SSI can be conducted in a low-income hospital setting, although dedicated staff, intensive training and local modifications to surveillance methods are necessary. Surveillance for post-discharge SSI using telephone calls is imperfect but provides a practical alternative to clinic-based diagnosis. The SWC score was the only predictor of SSI risk in O&G surgery in this context.

The TP53 tumour-suppressor gene is expressed as several protein isoforms generated by different mechanisms, including use of alternative promoters, splicing sites and translational initiation sites, that are conserved through evolution and within the TP53 homologues, TP63 and TP73. Although first described in the eighties, the importance of p53 isoforms in regulating the suppressive functions of p53 has only become evident in the last 10 years, by analogy with observations that p63 and p73 isoforms appeared indispensable to fully understand the biological functions of TP63 and TP73. This review summarizes recent advances in the field of ‘p53 isoforms', including new data on p63 and p73 isoforms. Details of the alternative mechanisms that produce p53 isoforms and cis- and trans-regulators identified are provided. The main focus is on their biological functions (apoptosis, cell cycle, aging and so on) in cellular and animal models, including mouse, zebrafish and Drosophila. Finally, the deregulation of p53 isoform expression in human cancers is reviewed. Based on these latest results, several developments are expected in the future: the identification of drugs modulating p53 isoform expression; the generation of animal models and the evaluation of the use of p53 isoform as biomarkers in human cancers.

DB289 is the first oral drug shown in clinical trials to have efficacy in treating African trypanosomiasis (African sleeping sickness). Mild liver toxicity was noted but was not treatment limiting. However, development of DB289 was terminated when several treated subjects developed severe kidney injury, a liability not predicted from preclinical testing. We tested the hypothesis that the kidney safety liability of DB289 would be detected in a mouse diversity panel (MDP) comprised of 34 genetically diverse inbred mouse strains. MDP mice received 10 days of oral treatment with DB289 or vehicle and classical renal biomarkers blood urea nitrogen (BUN) and serum creatinine (sCr), as well as urine biomarkers of kidney injury were measured. While BUN and sCr remained within reference ranges, marked elevations were observed for kidney injury molecule-1 (KIM-1) in the urine of sensitive mouse strains. KIM-1 elevations were not always coincident with elevations in alanine aminotransferase (ALT), suggesting that renal injury was not linked to hepatic injury. Genome-wide association analyses of KIM-1 elevations indicated that genes participating in cholesterol and lipid biosynthesis and transport, oxidative stress, and cytokine release may play a role in DB289 renal injury. Taken together, the data resulting from this study highlight the utility of using an MDP to predict clinically relevant toxicities, to identify relevant toxicity biomarkers that may translate into the clinic, and to identify potential mechanisms underlying toxicities. In addition, the sensitive mouse strains identified in this study may be useful in screening next-in-class compounds for renal injury.

SUMMARY

Although Toll-like receptor 9 (TLR9) has been implicated in regulating cytokine and type I interferon (IFN) production during malaria in humans and mice, the high AT content of the Plasmodium falciparum genome prompted us to examine the possibility that malarial DNA triggered TLR9-independent DNA sensing pathways. Over 6000 ATTTTTAC (“AT-rich”) motifs are present in the genome of P. falciparum, which we show here potently induce type I IFNs. Parasite DNA, parasitized erythrocytes and oligonucleotides containing the AT-r motif induce type I IFNs via a pathway that did not involve previously described sensors including TLR9, DAI, RNA polymerase-III or IFI16/p204. Rather, AT-rich DNA sensing involved an unknown receptor that coupled to STING, TBK1 and IRF3-IRF7 signaling pathway. Mice lacking both IRF3 and IRF7, the kinase TBK1 or the type I IFN receptor were resistant to otherwise lethal cerebral malaria. Collectively, these observations implicate AT-rich DNA sensing via STING, TBK1 and IRF3-IRF7 in P. falciparum malaria.

Bladder cancer is the fifth most commonly diagnosed cancer and the most expensive adult cancer in average healthcare costs incurred per patient in the USA. However, little is known about factors influencing patients' treatment decisions, quality of life, and responses to treatment impairments. The main focus of this paper is to better understand the impact of muscle invasive bladder cancer on patient quality of life and its added implications for primary caregivers and healthcare providers. In this paper, we discuss treatment options, side effects, and challenges that patients and family caregivers face in different phases along the disease trajectory and further identify crucial areas of needed research.

SUMMARY

Vitamin A and its metabolite, retinoic acid (RA), have recently been implicated in the regulation of immune homeostasis via the peripheral induction of regulatory T cells. Here we show that RA is also required to elicit proinflammatory CD4+ helper T cell responses to infection and mucosal vaccination. Retinoic acid receptor alpha (RARα) is the critical mediator of these effects. Strikingly, antagonism of RAR signaling and deficiency in RARα(Rara−/−) results in a cell autonomous CD4+ T cell activation defect. Altogether, these findings reveal a fundamental role for the RA/RARα axis in the development of both regulatory and inflammatory arms of adaptive immunity and establish nutritional status as a broad regulator of adaptive T cell responses.

Genome-wide association studies (GWAS) have demonstrated a significant polygenic contribution to bipolar disorder (BD) where disease risk is determined by the summation of many alleles of small individual magnitude. Modelling polygenic risk scores may be a powerful way of identifying disrupted brain regions whose genetic architecture is related to that of BD. We determined the extent to which common genetic variation underlying risk to BD affected neural activation during an executive processing/language task in individuals at familial risk of BD and healthy controls. Polygenic risk scores were calculated for each individual based on GWAS data from the Psychiatric GWAS Consortium Bipolar Disorder Working Group (PGC-BD) of over 16 000 subjects. The familial group had a significantly higher polygene score than the control group (P=0.04). There were no significant group by polygene interaction effects in terms of association with brain activation. However, we did find that an increasing polygenic risk allele load for BD was associated with increased activation in limbic regions previously implicated in BD, including the anterior cingulate cortex and amygdala, across both groups. The findings suggest that this novel polygenic approach to examine brain-imaging data may be a useful means of identifying genetically mediated traits mechanistically linked to the aetiology of BD.

Background:

Air pollution in Tehran is widely recognized as a serious environmental challenge, posing significant threats to the health of the resident population. Improving air quality will be difficult for many reasons, including climate and topography, heavy dependence on motor vehicles for mobility, and limited resources to reduce polluting emissions. Consequently, it is useful to have information regarding the scale of the health threat and the economic value of reducing that threat.

Methods:

This paper integrates information on air quality, population, economic valuation, and health science to assess the most serious impact of fine particle pollution on humans, which is increased mortality risk, and provides estimates of the costs of present pollution levels, both in terms of risk and in terms of economic value relative to attaining air quality standards.

Results:

Mid-range results indicate that mortality risk for the population aged 30 and over would be reduced from 8.2 per 1,000 residents annually to 7.4 per 1,000 and that the estimated annual economic benefits of this reduced risk would be $378.5 million, if health-based World Health Organization-recommended annual average PM2.5 standards were met.

Conclusions:

The potential public health benefits of reducing particulate air pollution are significant, and will increase with growing population.

Background:

People with colorectal cancer have impaired quality of life (QoL). We investigated what factors were most highly associated with it.

Methods:

Four hundred and ninety-six people with colorectal cancer completed questionnaires about QoL, functioning, symptoms, co-morbidity, cognitions and personal and social factors. Disease, treatment and co-morbidity data were abstracted from case notes. Multiple linear regression identified modifiable and unmodifiable factors independently predictive of global quality of life (EORTC-QLQ-C30).

Results:

Of unmodifiable factors, female sex (P<0.001), more self-reported co-morbidities (P=0.006) and metastases at diagnosis (P=0.036) significantly predicted poorer QoL, but explained little of the variability in the model (R2=0.064). Adding modifiable factors, poorer role (P<0.001) and social functioning (P=0.003), fatigue (P=0.001), dyspnoea (P=0.001), anorexia (P<0.001), depression (P<0.001) and worse perceived consequences (P=0.013) improved the model fit considerably (R2=0.574). Omitting functioning subscales resulted in recent diagnosis (P=0.002), lower perceived personal control (P=0.020) and travel difficulties (P<0.001) becoming significant predictors.

Conclusion:

Most factors affecting QoL are modifiable, especially symptoms (fatigue, anorexia, dyspnoea) and depression. Beliefs about illness are also important. Unmodifiable factors, including metastatic (or unstaged) disease at diagnosis, have less impact. There appears to be potential for interventions to improve QoL in patients with colorectal cancer.

Objectives

Previous studies have shown that adult listeners are more adept than child listeners at identifying spectrally-degraded speech. However, the development of the ability to combine speech information from different frequency regions has received little previous attention. The purpose of the present study was to determine the effect of age on the bandwidth necessary to achieve a relatively low criterion level of speech recognition for two frequency bands, then to determine the improvement in speech recognition that resulted when both speech bands were present simultaneously.

Design

Listeners in the present study included normal-hearing children (6–14 years old, n=18) and adults (n=11). In the first stage of testing, sentences were bandpass-filtered around either 500 or 2500 Hz, and the bandwidth of that filter was varied adaptively to determine the width required for approximately 15–25% correct speech recognition. In the second stage of testing, these criterion bandwidths were presented in fixed block trials with either one band or both bands, and percent correct performance was determined.

Results

Results suggest that age is inversely associated with the bandwidth required to achieve a relatively low criterion level of speech recognition for speech bands centered at either 500 Hz or 2500 Hz. However, both adults and children show a similar, large improvement in performance when both bands are presented simultaneously.

Conclusions

Although younger children require more bandwidth to correctly recognize speech filtered around a single frequency, they appear to be relatively adept at integrating frequency-distributed information to recognize a composite stimulus.

Background

Toll-like receptor 4 (TLR4) is activated by bacterial endotoxin, a prototypical pathogen-associated molecular pattern (PAMP). It has been suggested that TLR4 can also be activated by damage-associated molecular pattern (DAMP) proteins such as HSP70. It remains a challenge to provide unequivocal evidence that DAMP proteins themselves play a role in TLR4 activation, as the DAMP proteins used are often contaminated with endotoxin and other TLR ligands introduced during protein expression and/or purification.

Results

Here we report that the activation of TLR4 on primary human macrophage cultures by recombinant HSP70 is not solely due to contaminating endotoxin. Polymyxin B pretreatment of HSP70 preparations to neutralize contaminating endotoxin caused significant reductions in the amount of TNF-α induced by the recombinant protein as determined by ELISA. However, digestion of HSP70 with Proteinase K-agarose beads also dramatically reduced the TNF-α response of macrophages to HSP70, while leaving levels of contaminating endotoxin largely unchanged relative to controls.

Conclusions

These results indicate that the stimulatory effect of recombinant HSP70 requires both the presence of endotoxin and structural integrity of the heat shock protein itself.

Background:

Degradation and chemical modification of RNA in formalin-fixed paraffin-embedded (FFPE) samples hamper their use in expression profiling studies. This study aimed to show that useful information can be obtained by Exon-array profiling archival FFPE tumour samples.

Methods:

Nineteen cervical squamous cell carcinoma (SCC) and 9 adenocarcinoma (AC) FFPE samples (10–16-year-old) were profiled using Affymetrix Exon arrays. The gene signature derived was tested on a fresh-frozen non-small cell lung cancer (NSCLC) series. Exploration of biological networks involved gene set enrichment analysis (GSEA). Differential gene expression was confirmed using Quantigene, a multiplex bead-based alternative to qRT–PCR.

Results:

In all, 1062 genes were higher in SCC vs AC, and 155 genes higher in AC. The 1217-gene signature correctly separated 58 NSCLC into SCC and AC. A gene network centered on hepatic nuclear factor and GATA6 was identified in AC, suggesting a role in glandular cell differentiation of the cervix. Quantigene analysis of the top 26 differentially expressed genes correctly partitioned cervix samples as SCC or AC.

Conclusion:

FFPE samples can be profiled using Exon arrays to derive gene expression signatures that are sufficiently robust to be applied to independent data sets, identify novel biology and design assays for independent platform validation.

Under physiological conditions the gut associated lymphoid tissues not only prevent the induction of a local inflammatory immune response, but also induce systemic tolerance to fed antigens1,2. A notable counter-example is celiac disease, where genetically susceptible individuals expressing HLA-DQ2 or HLA-DQ8 molecules develop inflammatory T cell and antibody responses against dietary gluten, a protein present in wheat3. The mechanisms underlying this dysregulated mucosal immune response to a soluble antigen have not been identified. Retinoic acid, a metabolite of vitamin A, was shown to play a critical role in the induction of intestinal regulatory responses4–6. We found that in conjunction with IL-15, a cytokine greatly upregulated in the gut of celiac disease patients, retinoic acid rapidly activated dendritic cells to induce JNK phosphorylation and release the proinflammatory cytokines IL-12p70 and IL-23. As a result, in a stressed intestinal environment, retinoic acid acted as an adjuvant that promoted rather than prevented inflammatory cellular and humoral responses to fed antigen. Altogether, these findings unveil an unexpected role for retinoic acid and IL-15 in the abrogation of tolerance to dietary antigens.

We report pure-tone hearing threshold findings in 56 college students. All subjects reported normal hearing during telephone interviews, yet not all subjects had normal sensitivity as defined by well-accepted criteria. At one or more test frequencies (0.25–8 kHz), 7% of ears had thresholds ≥25 dB HL and 12% had thresholds ≥20 dB HL. The proportion of ears with abnormal findings decreased when three-frequency pure-tone-averages were used. Low-frequency PTA hearing loss was detected in 2.7% of ears and high-frequency PTA hearing loss was detected in 7.1% of ears; however, there was little evidence for “notched” audiograms. There was a statistically reliable relationship in which personal music player use was correlated with decreased hearing status in male subjects. Routine screening and education regarding hearing loss risk factors are critical as college students do not always self-identify early changes in hearing. Large-scale systematic investigations of college students’ hearing status appear to be warranted; the current sample size was not adequate to precisely measure potential contributions of different sound sources to the elevated thresholds measured in some subjects.

Methyl-CpG-binding protein 2 (MeCP2) is a chromatin-binding protein that mediates transcriptional regulation, and is highly abundant in brain. The nature of its binding to reconstituted templates has been well characterized in vitro. However, its interactions with native chromatin are less understood. Here we show that MeCP2 displays a distinct distribution within fractionated chromatin from various tissues and cell types. Artificially induced global changes in DNA methylation by 3-aminobenzamide or 5-aza-2′-deoxycytidine, do not significantly affect the distribution or amount of MeCP2 in HeLa S3 or 3T3 cells. Most MeCP2 in brain is chromatin-bound and localized within highly nuclease-accessible regions. We also show that, while in most tissues and cell lines, MeCP2 forms stable complexes with nucleosome, in brain, a fraction of it is loosely bound to chromatin, likely to nucleosome-depleted regions. Finally, we provide evidence for novel associations of MeCP2 with mononucleosomes containing histone H2A.X, H3K9me2 and H3K27me3 in different chromatin fractions from brain cortex and in vitro. We postulate that the functional compartmentalization and tissue-specific distribution of MeCP2 within different chromatin types may be directed by its association with nucleosomes containing specific histone variants, and post-translational modifications.

Selenium (Se) is essential for human health. Despite evidence that Se intake affects inflammatory responses, the mechanisms by which Se and the selenoproteins modulate inflammatory signalling, especially in the gut, are not yet defined. The aim of this work was to assess effects of altered Se supply and knock-down of individual selenoproteins on NF-κB activation in gut epithelial cells. Caco-2 cells were stably transfected with gene constructs expressing luciferase linked either to three upstream NF-κB response elements and a TATA box or only a TATA box. TNFα and flagellin activated NF-κB-dependent luciferase activity and increased IL-8 expression. Se depletion decreased expression of glutathione peroxidase1 (GPX1) and selenoproteins H and W and increased TNFα-stimulated luciferase activity, endogenous IL-8 expression and reactive oxygen species (ROS) production. These effects were not mimicked by independent knock-down of either GPX1, selenoprotein H or W; indeed, GPX1 knock-down lowered TNFα-induced NF-κB activation and did not affect ROS levels. GPX4 knock-down decreased NF-κB activation by flagellin but not by TNFα. We hypothesise that Se depletion alters the pattern of expression of multiple selenoproteins that in turn increases ROS and modulates NF-κB activation in epithelial cells, but that the effect of GPX1 knock-down is ROS-independent.

Selenium (Se) is essential for human health. Despite evidence that Se intake affects inflammatory responses, the mechanisms by which Se and the selenoproteins modulate inflammatory signalling, especially in the gut, are not yet defined. The aim of this work was to assess effects of altered Se supply and knock-down of individual selenoproteins on NF-κB activation in gut epithelial cells. Caco-2 cells were stably transfected with gene constructs expressing luciferase linked either to three upstream NF-κB response elements and a TATA box or only a TATA box. TNFα and flagellin activated NF-κB-dependent luciferase activity and increased IL-8 expression. Se depletion decreased expression of glutathione peroxidase1 (GPX1) and selenoproteins H and W and increased TNFα-stimulated luciferase activity, endogenous IL-8 expression and reactive oxygen species (ROS) production. These effects were not mimicked by independent knock-down of either GPX1, selenoprotein H or W; indeed, GPX1 knock-down lowered TNFα-induced NF-κB activation and did not affect ROS levels. GPX4 knock-down decreased NF-κB activation by flagellin but not by TNFα. We hypothesise that Se depletion alters the pattern of expression of multiple selenoproteins that in turn increases ROS and modulates NF-κB activation in epithelial cells, but that the effect of GPX1 knock-down is ROS-independent.

Background:

Patients who have completed initial cancer treatment (cancer survivors) have been relatively neglected. We need data to help us better understand the needs of this group and to underpin evidence-based service development.

Methods:

Scoping reviews of research published in the last two decades focussing on the problems faced by cancer survivors, and the effectiveness of interventions for these problems were undertaken. The aim was to identify what we know, what we do not know and opportunities where research could provide new information. We searched for, retrieved and rapidly appraised systematic reviews sourced from the most common electronic databases supplemented by more recently published individual studies.

Results:

The research evidence is surprisingly limited. We have some knowledge of the prevalence and nature of depression, pain and fatigue in cancer survivors. We know much less about cognitive and physical impairment, employment, financial well-being and relationships. Even where we have evidence, it is mostly of only moderate quality, is most often only for breast cancer and focuses almost exclusively on the early phase of survivorship. We have good evidence for the effectiveness of drug treatments for pain and moderate evidence for fatigue and depression, but not for other symptoms. Interventions based on rehabilitative and self-management approaches remain in the early stages of evaluation.

Interpretation:

There has been a substantial amount of research describing many of the problems experienced by the cancer survivors. This is strongest in the area of symptoms in the period soon after treatment. However, the quality of the evidence is often poor, and some topics have been little examined. We urgently need data on the natural evolution and scale of the problems of cancer survivors obtained from well-designed, large-scale cohort studies and the robust testing of interventions in clinical trials. Given the current financially constrained research funding environment, we suggest areas in which strategic investment might give findings that have the potential to make a major impact on patient well-being in a 5-year time scale.

Objective

It was recently demonstrated that the Clinical Dementia Rating scale (CDR) Sum of Boxes (CDR-SB) score can be used to accurately stage severity of Alzheimer’s dementia (AD) and Mild Cognitive Impairment (MCI)1. However, to date, the utility of those interpretive guidelines has not been cross-validated or applied to a heterogeneous sample of dementia cases. This study sought to cross-validate the staging guidelines proposed by those authors utilizing the National Alzheimer’s Coordinating Center (NACC) database.

Method

There were 12,462 participants (Controls n = 5,115, MCI n = 2,551, dementia all etiologies n = 4796) in the NACC dataset utilized for the current analysis. The previously published cut-scores were applied to the NACC sample and diagnostic accuracy estimates obtained. Next, analyses were restricted to NACC participants with CDR-Global Score (CDR-GS) of 0.5 and ROC curves generated to determine optimal CDR-SB cut-scores for distinguishing MCI from very early dementia.

Results

The previously proposed CDR-SB ranges successfully classified the vast majority of patients across all impairment ranges with a κ of 0.91 and 94% overall correct classification rate. Additionally, the CDR-SB score discriminated between patients diagnosed with MCI and dementia when CDR-GS were restricted to 0.5 (overall AUC = 0.83).

Conclusions

These findings cross-validate the previously published CDR-SB interpretative guidelines for staging dementia severity and extend those findings to a large heterogeneous sample of patients with dementia. Additionally, the CDR-SB scores distinguished MCI from dementia in patients with reasonable accuracy when CDR-GS is restricted to 0.5.

Background

During whole genome microarray‐based comparative genomic hybridisation (array CGH) screening of subjects with idiopathic intellectual disability, we identified two unrelated individuals with a similar de novo interstitial microdeletion at 2p15‐2p16.1. Both individuals share a similar clinical phenotype including moderate to severe intellectual disability, autism/autistic features, microcephaly, structural brain anomalies including cortical dysplasia/pachygyria, renal anomalies (multicystic kidney, hydronephrosis), digital camptodactyly, visual impairment, strabismus, neuromotor deficits, communication and attention impairments, and a distinctive pattern of craniofacial features. Dysmorphic craniofacial features include progressive microcephaly, flat occiput, widened inner canthal distance, small palpebral fissures, ptosis, long and straight eyelashes, broad and high nasal root extending to a widened, prominent nasal tip with elongated, smooth philtrum, rounding of the upper vermillion border and everted lower lips.

Methods

Clinical assessments, and cytogenetic, array CGH and fluorescence in situ hybridisation (FISH) analyses were performed.

Results

The microdeletions discovered in each individual measured 4.5 Mb and 5.7 Mb, spanning the chromosome 2p region from 57.2 to 61.7 Mb and from 56 to 61.7 Mb, respectively. Each deleted clone in this range demonstrated a dosage reduction from two to one copy in each proband except for clone RP11‐79K21, which was present in three copies in each proband and in four copies in their respective parents (two per each chromosome 2 homologue).

Discussion

The common constellation of features found in the two affected subjects indicates that they have a newly recognised microdeletion syndrome involving haploinsufficiency of one or more genes deleted within at least a 4.5‐Mb segment of the 2p15‐16.1 region.

Accurate determination of the complex shear modulus of soft tissues and soft-tissue-like materials in the 10–300 Hz frequency range is very important to researchers in MR elastography and acoustic radiation force impulse (ARFI) imaging. A variety of instruments for making such measurements has been reported, but none of them is easily reproduced, and none have been tested to conform to causality via the Kramers–Kronig (K-K) relations. A promising linear oscillation instrument described in a previous brief report operates between 20 and 160 Hz, but results were not tested for conformity to the K-K relations. We have produced a similar instrument with our own version of the electronic components and have also accounted for instrumental effects on the data reduction, which is not addressed in the previous report. The improved instrument has been shown to conform to an accurate approximation of the K-K relations over the 10–300 Hz range. The K-K approximation is based on the Weichert mechanical circuit model. We also found that the sample thickness must be small enough to obtain agreement with a calibrated commercial rheometer. A complete description of the improved instrument is given, facilitating replication in other labs.