Estimating ground reaction force with novel carbon nanotube-based textile insole pressure sensors

This study presents a new wearable insole pressure sensor (IPS), composed of fabric coated in a carbon nanotube-based composite thin film, and validates its use for quantifying ground reaction forces (GRFs) during human walking. Healthy young adults (n = 7) walked on a treadmill at three different speeds while data were recorded simultaneously from the IPS and a force plate (FP). The IPS was compared against the FP by evaluating differences between the two instruments under two different assessments: (1) comparing the two peak forces at weight acceptance and push-off (2PK) and (2) comparing the absolute maximum (MAX) of each gait cycle. Agreement between the two systems was evaluated using the Bland-Altman method. For the 2PK assessment, the group mean of differences (MoD) was -1.3 ± 4.3% body weight (BW) and the distance between the MoD and the limits of agreement (2S) was 25.4 ± 11.1% BW. For the MAX assessment, the average MoD across subjects was 1.9 ± 3.0% BW, and 2S was 15.8 ± 9.3% BW. The results of this study show that this sensor technology can be used to obtain accurate measurements of peak walking forces with a basic calibration and consequently open new opportunities to monitor GRF outside of the laboratory.

Development and Validation of a Framework for Predictive Simulation of Treadmill Gait

Treadmill training is a common intervention to promote healthy walking function for individuals with pathological gait. However, because of the heterogeneity of many patient populations, determining how an individual will respond to new treadmill protocols may require extensive trial and error, causing increased patient fatigue. This article provides instructions for the development and validation of a framework for predictive simulation of treadmill gait, which may be used in the design of treadmill training protocols. This was accomplished through three steps: predict motion of a simple model of a block relative to a treadmill, create a predictive framework to estimate gait with a 2D lower limb musculoskeletal model on a treadmill, and validate the framework by comparing predicted kinematics, kinetics, and spatiotemporal parameters across three belts speeds and between speed-matched overground and treadmill predictive simulations. Predicted states and ground reaction forces for the block-treadmill model were consistent with rigid body dynamics, and lessons learned regarding ground contact model and treadmill motion definition were applied to the gait model. Treadmill simulations at 0.7, 1.2, and 1.8 m/s belt speeds resulted in predicted sagittal plane joint angles, ground reaction forces, step length, and step time that closely matched experimental data at similar speeds. Predicted speed-matched overground and treadmill simulations resulted in small RMSE values within standard deviations for healthy gait. These results suggest that this predictive simulation framework is valid and can be used to estimate gait adaptations to various treadmill training protocols.

Determinants of lost theatre capacity

Secondary care Trusts nationwide are continuing to fail the 18-week referral to treatment (RTT) target despite several initiatives to improve theatre efficiency (2018 NHS England review). A limitation of wasted theatre productivity is required to alleviate pressures on waiting lists. Productivity, which is a measure of treatment time as a proportion of available/allocated time, takes into consideration variations in operator performance, early (non-funded) theatre starts, and over-run, and its analysis enables the determination of theatre downtime and lost theatre capacity. We monitored productivity over a 12-week period and performed downtime analysis as reported in the NHS Improvement national audit (NHSI). Results showed a marked but predictable variation in productivity connected to turnaround and session list scheduling. Productivity and booking efficiency correlated uniformly (Pearson's r=0.82). Theatre downtime was analysed with respect to three components defined in the NHSI national audit: late starts, early finish, and turnaround. We found that lost theatre time was predominantly due to early finishes; late starts were infrequent. Transport time correlated unfavourably with productivity (Pearson's r=-0.29, p=0.037) and over-run (r=0.44), and prolonged transport times were shorter when surgery was performed in a dedicated day surgery unit. Calculating the mean transport times for lists with high compared with low productivity helped us set a benchmark for patient transport times for future audit.

Confidential image transfer: an ethico-legal dilemma

Clinical photographs aid decision-making and represent important medicolegal records. Storage and transfer of images of the facial area must adhere to Caldicott Principles. Outside working hours, clinical photography services are often limited. Our Trust has introduced a Secure Clinical Image Transfer (SCIT) app allowing clinicians to take photographs on personal devices to be securely uploaded to the patient's electronic health record. To evaluate whether clinicians were taking clinical images in an insecure manner, clinicians completed an anonymous questionnaire before and after introduction of the SCIT app. The standard was 100% knowledge of, and adherence to, trust information governance guidelines. Response rate was 100% in both cycles. Introduction of the SCIT app reduced inappropriate clinical photography on personal devices. Our completed audit cycle shows that the SCIT app allows convenient, secure information capture on personal devices and automatic secure synchronisation to trust electronic health records.

Interdependence of balance mechanisms during bipedal locomotion

Our main interest is to identify how humans maintain upright while walking. Balance during standing and walking is different, primarily due to a gait cycle which the nervous system must contend with a variety of body configurations and frequent perturbations (i.e., heel-strike). We have identified three mechanisms that healthy young adults use to respond to a visually perceived fall to the side. The lateral ankle mechanism and the foot placement mechanism are used to shift the center of pressure in the direction of the perceived fall, and the center of mass away from the perceived fall. The push-off mechanism, a systematic change in ankle plantarflexion angle in the trailing leg, results in fine adjustments to medial-lateral balance near the end of double stance. The focus here is to understand how the three basic balance mechanisms are coordinated to produce an overall balance response. The results indicate that lateral ankle and foot placement mechanisms are inversely related. Larger lateral ankle responses lead to smaller foot placement changes. Correlations involving the push-off mechanism, while significant, were weak. However, the consistency of the correlations across stimulus conditions suggest the push-off mechanism has the role of small adjustments to medial-lateral movement near the end of the balance response. This verifies that a fundamental feature of human bipedal gait is a highly flexible balance system that recruits and coordinates multiple mechanisms to maintain upright balance during walking to accommodate extreme changes in body configuration and frequent perturbations.

Walking Cadence Affects the Recruitment of the Medial-Lateral Balance Mechanisms

We have previously identified three balance mechanisms that young healthy adults use to maintain balance while walking. The three mechanisms are: (1) The lateral ankle mechanism, an active modulation of ankle inversion/eversion in stance; (2) The foot placement mechanism, an active shift of the swing foot placement; and (3) The push-off mechanism, an active modulation of the ankle plantarflexion angle during double stance. Here we seek to determine whether there are changes in neural control of balance when walking at different cadences and speeds. Twenty-one healthy young adults walked on a self-paced treadmill while immersed in a 3D virtual reality cave, and periodically received balance perturbations (bipolar galvanic vestibular stimulation) eliciting a perceived fall to the side. Subjects were instructed to match two cadences specified by a metronome, 110 bpm (High) and 80 bpm (Low), which in this experiment, led to faster and slower gait speeds, respectively. The results indicate that subjects altered the use of the balance mechanisms at different cadences. The lateral ankle mechanism was used more in the Low condition, while the foot placement mechanism was used more in the High condition. There was no difference in the use of the push-off mechanism between cadence conditions. These results suggest that neural control of balance is altered when gait characteristics, such as cadence change, suggesting a flexible balance response that is sensitive to the constraints of the gait cycle. We speculate that the use of the balance mechanisms may be a factor resulting in well-known characteristics of gait in populations with compromised balance control, such as slower gait speed in older adults or higher cadence in people with Parkinson's disease.

A-12 Neuroticism and Extraversion are Related to Dual Task Postural Stability in Healthy Young Adults

Objective

The relation between personality and postural stability has received little attention. This study addressed whether neuroticism and extraversion are related to changes in postural stability and cognitive functioning during a standing balance task.

Method

Thirty-two healthy young adults completed a personality measure and two cognitive tasks, a 2-back task and a weather prediction task (WPT), both while seated and in tandem stance on a foam mat. Sway was quantified via normalized path lengths, and correlation coefficients were calculated between neuroticism, extraversion and dual task changes in postural stability and cognitive functioning.

Results

Consistent with predictions, higher neuroticism was related to increased dual task sway during the 2-back task, r = 0.40, p = 0.023, and lower extraversion was related to increased dual task sway during the WPT, r = -0.43, p = 0.013.

Conclusions

The results suggest that personality is related to postural stability in healthy young adults and that personality should be considered in the prediction of individuals at risk for falling or in the treatment of individuals with balance difficulties. The task-specific nature of the relation is discussed and may be due to differences in anxiety or underlying brain mechanisms between high neuroticism and low extraversion.

A-26 Performance on Design Fluency and Visuoperception Measures is Related to Single and Dual Task Treadmill Gait Parameters in Healthy Adults

Objective

Research suggests a link between gait and cognition. Executive functions have been related to gait speed, however the relation between design fluency and visuoperception and other spatiotemporal gait characteristics that are related to falling is unclear. The objective of the study was to determine whether performance on design fluency and visuoperception tasks is related to spatiotemporal gait parameters during single and dual task treadmill walking in a sample of healthy adults.

Method

Nineteen healthy adults averaging 40 years of age completed cognitive measures of design fluency, visual attention, and visuoperception. They underwent gait analysis while walking on an instrumented treadmill in single task and dual task conditions.

Results

Performance on Spatial Span significantly correlated with single task stride length, r = 0.47, p = 0.043. Performance on Block Design significantly correlated with dual task stride length, r = 0.46, p = 0.049. Performance on Design Fluency significantly correlated with single task stride length variability, r = -0.50, p = 0.030, dual task stride length variability, r = -0.62, p = 0.005, and dual task step width variability, r = -0.56, p = 0.012. Performance on Picture Completion also correlated with dual task step width variability, r = -0.54, p = 0.017.

Conclusions

Design fluency and visuoperception appear related to spatiotemporal gait parameters in healthy adults. Worse cognitive performance was related to greater variability in dual task stride length and step width, gait characteristics associated with falling in aging and neurological populations.

Playskin Lift: Development and Initial Testing of an Exoskeletal Garment to Assist Upper Extremity Mobility and Function

BACKGROUND

A person's ability to move his or her arms against gravity is important for independent performance of critical activities of daily living and for exploration that facilitates early cognitive, language, social, and perceptual-motor development. Children with a variety of diagnoses have difficulty moving their arms against gravity.

OBJECTIVE

The purpose of this technical report is to detail the design process and initial testing of a novel exoskeletal garment, the Playskin Lift, that assists and encourages children to lift their arms against gravity.

DESIGN

This report details the design theory and process, the device, and the results of field testing with a toddler with impaired upper extremity function due to arthrogryposis multiplex congenita.

RESULTS

The Playskin Lift is an inexpensive (<$30 material costs), easy to use (5/5 rating), comfortable (5/5 rating), and attractive (4/5 rating) device. While wearing the device, the child was able to contact objects more often throughout an increased play space, to look at toys more while contacting them, and to perform more complex interactions with toys.

LIMITATIONS

This report details initial testing with one child. Future testing with more participants is recommended.

CONCLUSIONS

These results suggest that by considering the broad needs of users, including cost, accessibility, comfort, aesthetics, and function, we can design inexpensive devices that families and clinicians can potentially fabricate in their own communities to improve function, participation, exploration, and learning for children with disabilities.

Sensitivity of estimated muscle force in forward simulation of normal walking

Generic muscle parameters are often used in muscle-driven simulations of human movement to estimate individual muscle forces and function. The results may not be valid since muscle properties vary from subject to subject. This study investigated the effect of using generic muscle parameters in a muscle-driven forward simulation on muscle force estimation. We generated a normal walking simulation in OpenSim and examined the sensitivity of individual muscle forces to perturbations in muscle parameters, including the number of muscles, maximum isometric force, optimal fiber length, and tendon slack length. We found that when changing the number of muscles included in the model, only magnitude of the estimated muscle forces was affected. Our results also suggest it is especially important to use accurate values of tendon slack length and optimal fiber length for ankle plantar flexors and knee extensors. Changes in force production by one muscle were typically compensated for by changes in force production by muscles in the same functional muscle group, or the antagonistic muscle group. Conclusions regarding muscle function based on simulations with generic musculoskeletal parameters should be interpreted with caution.

Implications for future studies in humans

While an environmental link with cancer is widely accepted, its implications are not always understood. Because of the multistage nature of carcinogenesis, it is insufficient to study initiation only at the level of the 'target cell', since events before and after initiation may prove pivotal to neoplastic development. Estimates of the relative contributions of factors causing human cancer are briefly summarized. Tumours related to patterns of life style--including diet and behaviour--and individual susceptibility are discussed. It is in this group of tumours that metabolizing enzymes are probably most significant, especially for weak initiating stimuli, whether extrinsic or intrinsic. There are few epidemiological data available at present but future research can be suggested, to improve the definition in biochemical terms of individual susceptibility and effects of life style.

The symmetry angle: a novel, robust method of quantifying asymmetry

Quantification of asymmetry is a common objective in both research and clinical settings. The most common method for quantification of asymmetry of discrete variables is calculation of the symmetry index. Essentially a measure of the percent difference between sides, the symmetry index requires the choice of a reference value. This is a limitation as the choice of value is not always clear, and can lead to inconsistent results and artificially inflated values. Therefore, the purposes of the current study were to examine the limitations of the symmetry index in depth, define a new method of quantifying symmetry that is robust to those limitations (the symmetry angle), and compute the correlations between the two measures. The results showed that, when using the symmetry index, the interpretation of asymmetry can be highly affected by the choice of reference value. The symmetry angle does not require the choice of a reference value. Therefore, it is not prone to the same limitations. While symmetry angle values tend to be smaller than symmetry index values, the measures are very highly correlated. This suggests that the symmetry angle is a good substitute for the symmetry index. Future studies of asymmetry may benefit from the use of the symmetry angle, as it is equally effective for identifying intra-limb differences as the symmetry index, but is not prone to problems due to normalization and provides a standard scale (+/-100%) to interpret results.

Clinicopathological correlates of IgM paraproteinemias

IgM paraproteinemia is considered to be the major defining feature of Waldenström's macroglobulinemia (WM), but it may also occur in other B-cell lymphoproliferative disorders. In this study we have reviewed the final pathological diagnosis of 106 patients with IgM paraproteinemia investigated in our laboratories between April 1993 and May 1999. In 22 of the 106 patients (20.8%), there was no clinical or laboratory evidence of an underlying lymphoproliferative disorder, and a diagnosis of monoclonal gammopathy of undetermined significance (MGUS) was therefore made. In 60 cases (56.6%), a diagnosis of WM was made, while in the remaining 24 patients, the final diagnosis was chronic lymphocytic leukemia (n = 10), diffuse large B-cell lymphoma (n = 5), extranodal marginal-zone lymphoma (n = 3), follicular lymphoma (n = 3), and mantle-cell lymphoma (n = 3). The median paraprotein concentration in patients with WM, MGUS, and "other" lymphoproliferative disorders was 13 g/L (range, 2-54), 6 g/L (range, 3-30), and 4.5 g/L (range, 3-61), respectively. It is clear that IgM paraproteins are demonstrable in all subtypes of peripheral B-cell disorders and, although paraprotein concentrations are generally higher in WM, there is considerable overlap. Immunophenotypic criteria are therefore essential for the accurate diagnosis of WM.

Disulfide connectivity in cerebroside sulfate activator is not necessary for biological activity or alpha-helical content but is necessary for trypsin resistance and strong ligand binding

Cerebroside sulfate activator (CSAct) protein is exceptionally resistant to heat denaturation and proteolytic digestion. Although water soluble the protein binds membrane-associated lipids. Its biological role is thought to be to transfer certain lipids between membranes and to facilitate their catabolism in the lysosomes. An example of the latter is the removal of the sulfate group from cerebroside sulfate by arylsulfatase A. The mechanism of lipid sequestration from membranes and presentation of the lipid-protein complex to catabolic enzymes is a crucial aspect of the function of this protein. The widespread occurrence of the protein class of which CSAct is one of the best known members underscores the significance of this protein. The preparation, purification and chemical and biological properties of a stable disulfide blocked derivative of CSAct is described. The pyridoethylated protein was susceptible to tryptic attack and devoid of a significant population of solvent-protected exchange resistant protons. It apparantly formed a CS complex. However, unlike the complex with the native protein, this was not sufficiently stable to remain intact during size exclusion chromatography. The disulfide-blocked protein had a similar CD spectrum as native protein, indicating similar alpha-helical content. Unexpectedly, the activities of disulfide-blocked protein in the arylsulfatse A catalyzed sulfate hydrolysis from cerebroside sulfate were substantial. Hitherto, it had been assumed that the disulfide connectivities were essential for the protein to maintain a correctly folded configuration to bind lipid ligands and potentiate their hydrolysis. Some revision of our thoughts on the importance of the disulfide connectivities in the structure and function of the protein are necessary.

Hydrogen-deuterium exchange signature of porcine cerebroside sulfate activator protein

Hydrogen-deuterium exchange can be a sensitive indicator of protein structural integrity. Comparisons were made between cerebroside sulfate activator protein (CSAct) in the native state and after treatment with guanidine hydrochloride plus dithiothreitol. Native protein has three internal disulfide bonds and treated protein has no internal disulfide bonds. The comparisons were made using hydrogen-deuterium exchange measured by electrospray ionization mass spectrometry, percentage alpha-helical content measured by circular dichroism and biological activity measured by the ability to support arylsulfatase A-catalyzed sulfate hydrolysis from cerebroside sulfate. In acidic solvent native protein has 59 exchange refractory protons and treated protein has 20 exchange refractory protons (44 and 14% of the exchangeable proton populations, respectively). In native protein the size of the exchange refractory proton population is sensitive to changes in pH, temperature and the presence of a ligand. It is uninfluenced by the presence or absence of glycosyl groups attached to Asn21. Helical content is virtually identical in native and treated protein. Biological activity is significantly reduced but not obliterated in treated protein. The hydrogen-deuterium exchange profile appears to be a sensitive signature of the correctly folded protein, and reflects a dimension of the protein structure that is not apparent in circular dichroic spectra or in the ability of the protein to support arylsulfatase A-catalyzed sulfate hydrolysis from sulfatide. The hydrogen-deuterium exchange profile will be a valuable criterion for characterizing mutant forms of CSAct produced by recombinant and synthetic paradigms and also the native and mutant forms of related proteins.

Cerebroside sulfate activator protein (Saposin B): chromatographic and electrospray mass spectrometric properties

Cerebroside sulfate activator protein is a small, heat-stable protein that is exceptionally resistant to proteolytic attack. This protein is essential for the catabolism of cerebroside sulfate and several other glycosphingolipids. Protein purified from pig kidney and human urine was extensively characterized by reversed-phase liquid chromatography and electrospray mass spectrometry. These two sources revealed 20 and 18 different molecular isoforms of the protein, respectively. Plausible explanations of the structures of the majority of these isoforms can be made on the basis of accurate molecular mass assignments. The reversed-phase chromatographic and electrospray mass spectrometric properties of enzymatically deglycosylated and disulfide-reduced protein were also compared. In addition to a demonstration of the power of electrospray ionization mass spectrometry for revealing a wealth of information on protein microheterogeneity and structural detail, the results also demonstrate the utility of this technique for monitoring spontaneous chemical and enzymatically mediated changes that occur as a result of metabolic processing and protein purification.

Discriminant analysis of biochemical parameters in liver disease

Discriminant function analysis has been used to investigate the relative value of six biochemical parameters (plasma ferritin, C-reactive-protein, bilirubin, alkaline phosphatase, glutamic oxaloacetic acid transaminase and albumin) in the diagnosis of liver disease. This was done among four groups totalling 70 subjects including healthy controls and patients with acute viral hepatitis, liver cirrhosis and primary hepatocellular carcinoma. Albumin had most value in distinguishing between groups, followed cumulatively by ferritin, alkaline phosphatase, C-reactive protein, bilirubin and glutamic oxaloacetic acid transaminase. However, if data on albumin, alkaline phosphatase, bilirubin and glutamic oxaloacetic acid transaminase had already been routinely collected, there would be no advantage in collecting data on ferritin and C-reactive protein. Any four of the six parameters would be of about equal value in distinguishing between diagnostic groups. When the data on all six biochemical parameters was combined in an optimum way, about 66% of all individuals could be correctly assigned to one of the four groups using biochemical markers alone. While the control subjects and patients with acute viral hepatitis formed a relatively well defined, tight cluster (apart from two patients with acute viral hepatitis), patients with liver cirrhosis and primary hepatocellular carcinoma were almost indistinguishable, using these biochemical parameters. If the latter two groups were pooled, then about 86% of subjects could be correctly classified.

The acute phase protein response in patients receiving subcutaneous IL-6

IL-6, tumour necrosis factor-alpha (TNF-alpha) and IL-1 are thought to be the key mediators of the acute phase response although much of the evidence is based on in vitro studies. It is not clear to what extent each of the acute phase proteins are regulated in vivo by each of these cytokines. The aim of this study was to examine the effects of IL-6 treatment in eight patients with cancer on the concentrations of an extensive range of positive and negative acute phase proteins. It was part of a larger investigation to assess the value of IL-6 in the management of chemotherapy-induced thrombocytopenia. IL-6 was administered by a daily subcutaneous injection for 7 days at a dose level of 1, 3, or 10 micrograms/kg/day. Increases in the positive acute phase proteins, serum amyloid A, C-reactive protein, alpha 1-acid glycoprotein, alpha 1-antichymotrypsin, haptoglobin, alpha 1-antitrypsin, fibrinogen, complement component C3, and caeruloplasmin, were observed, with the greatest incremental changes and fastest responses being seen for C-reactive protein and serum amyloid A protein. The negative acute phase proteins transferrin, transthyretin and retinol binding protein all fell to a nadir within 48-96 h after the first IL-6 injection. Increases in complement component C4 were only found in two patients, which may be related to the increase in circulating TNF-alpha concentrations found only in these patients. This study has therefore shown that IL-6 is capable of causing changes in the majority of acute phase proteins in vivo. Although secondary induction of TNF-alpha was not observed in the majority of patients examined, it is still possible however that other cytokines involved in regulation of the acute phase response, such as IL-1, may have been induced and contributed to the overall response.

A prospective study of the prevalence of clear-cut endocrine disorders and polycystic ovaries in 350 patients presenting with hirsutism or androgenic alopecia

OBJECTIVE

To determine the frequency of polycystic ovaries (PCO) on ultrasound and the incidence of clearcut endocrine disorders leading to virilization in patients complaining of hirsutism or androgenic alopecia. The major purpose was to determine a coherent policy for the routine biochemical assessment of such women.

DESIGN

A prospective study of women attending a joint skin/endocrine clinic complaining of these problems.

PATIENTS

Three hundred and fifty consecutive women with hirsutism and/or androgenic alopecia were assessed.

MEASUREMENTS

Baseline endocrine screens were conducted on two occasions and included measurement of serum testosterone, androstenedione, dehydroepiandrosterone sulphate, sex hormone binding globulin, LH, FSH, 17-hydroxyprogesterone and PRL. The ovaries were visualized by high-resolution pelvic ultrasound scanning.

RESULTS

Eight women were identified with relevant endocrine disorders; of these, one was acromegalic and one had a microprolactinoma--in both cases the association may have been fortuitous. Three had clear-cut 21-hydroxylase deficiency, one a rare hepatic enzyme deficiency (11-reductase), one a virilizing adrenal carcinoma and one a Leydig cell tumour. The latter six cases all had persistently elevated levels of serum testosterone (> 5 nmol/l). In all, 13 women had baseline testosterone levels in excess of 5 nmol/l. Polycystic ovaries were present in 81% of the cases who had erratic cycles and 52% of those with regular cycles; PCO were present in two of the women with 21-hydroxylase deficiency and in the woman with 11-oxoreductase deficiency. The Leydig cell tumour (1.2 cm diameter) was not detected on ultrasound or CT scan.

CONCLUSIONS

For the exclusion of enzyme deficiencies and virilizing tumours clinical assessment and a single serum testosterone measurement will suffice.

Environmental carcinogenesis

It generally is accepted that approximately 80% of all cancers have an environmental component. However, although the cause and nature of certain human cancers are known, definitive preventative guidelines cannot be offered for many tumors attributed to life style, especially those of the digestive and genitourinary system. This has led to considerable public confusion and political controversy regarding cancer control strategies. Proponents of two divergent strategies for control have emerged: those who emphasize increased regulatory programs designed to control or eliminate minute quantities of pollutants in the ambient environment based on fairly rigid quantitative risk assessment; and those who believe in more intensive long-term research on the molecular biologic mechanisms with the objective of actively intervening in carcinogenic mechanisms. Current data indicate that the eliminatory approach, apart from more effort on certain already recognized exogenous agents, will have little additional impact on the cancer burden. The mechanistic approach, although complex and slow, represents the most logical alternative. Thus, there are increasing efforts directed to evaluating the application of more recent advances in molecular biology to human studies. However, such research strategies require a long-term investment, and no time frame can be offered. Informed scientists have an important role in ensuring that the public is made aware of current scientific views on carcinogenesis and priorities in preventative research.

Abdominal irradiation in childhood; the potential for pregnancy

OBJECTIVE

To investigate the impact of premature ovarian failure due to whole abdominal radiotherapy (DXT) in childhood on uterine physical characteristics and blood flow and measuring the uterine response to exogenous sex steroid replacement.

DESIGN

A comparative observational study

SUBJECTS

10 women with premature ovarian failure due to treatment with whole abdominal irradiation in childhood. A comparison group of 22 women with premature ovarian failure who had not received whole abdominal DXT.

MAIN OUTCOME MEASURES

Uterine length and uterine blood flow measurement plus serial assessment of endometrial thickness during a cycle of exogenous sex steroid replacement.

RESULTS

Uterine length was significantly less (P less than 0.01) in women who had been exposed to whole abdominal DXT in childhood (mean 4.1 cm, 2SE 0.8) compared with a mean of 7.3 cm (2SE 0.6) in the comparison group. The three women in the DXT group who were studied serially had no increase in endometrial thickness in response to physiological sex steroid replacement therapy and most of the 10 irradiated women had no detectable uterine blood flow with Doppler ultrasound.

CONCLUSIONS

Uterine musculature and blood flow are irreversibly affected by high dose irradiation in childhood. Non-invasive assessment of this nature may predict potential for pregnancy following ovum donation and embryo transfer.

Restricted electrophoretic heterogeneity of immunoglobulin light chains in urine: a cause for confusion with Bence Jones protein

The detection of Bence Jones protein, an important part of the investigation of suspected myeloma, is most commonly done by agarose or cellulose nitrate electrophoresis followed by immunofixation. Bence Jones protein is recognized as single or multiple bands of one type of light chain. Unfortunately, improvements in sensitivity of these techniques (use of high-affinity antisera and higher resolution electrophoresis) frequently allow detection of multiple light chain bands in the urine of patients who do not have a B-cell dyscrasia. The bands are usually kappa, although they may be accompanied by lambda bands. This pattern may lead to the misdiagnosis of Bence Jones protein and oligoclonal light chain production in patients. Here we show that this pattern is produced by polyclonal light chains; it is present in the urine of all patients with a tubular proteinuria of any etiology and may be induced in healthy individuals by blocking their renal tubular protein reabsorption. Polyclonal light chains separate into monomers and dimers on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and into four major bands with many minor bands by isoelectric focusing. This difference in charge and possibly size results in the banding pattern seen on good-quality electrophoresis and immunofixation.

Restricted electrophoretic heterogeneity of immunoglobulin light chains in urine: a cause for confusion with Bence Jones protein

The detection of Bence Jones protein, an important part of the investigation of suspected myeloma, is most commonly done by agarose or cellulose nitrate electrophoresis followed by immunofixation. Bence Jones protein is recognized as single or multiple bands of one type of light chain. Unfortunately, improvements in sensitivity of these techniques (use of high-affinity antisera and higher resolution electrophoresis) frequently allow detection of multiple light chain bands in the urine of patients who do not have a B-cell dyscrasia. The bands are usually kappa, although they may be accompanied by lambda bands. This pattern may lead to the misdiagnosis of Bence Jones protein and oligoclonal light chain production in patients. Here we show that this pattern is produced by polyclonal light chains; it is present in the urine of all patients with a tubular proteinuria of any etiology and may be induced in healthy individuals by blocking their renal tubular protein reabsorption. Polyclonal light chains separate into monomers and dimers on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and into four major bands with many minor bands by isoelectric focusing. This difference in charge and possibly size results in the banding pattern seen on good-quality electrophoresis and immunofixation.

The value of C-reactive protein in the diagnosis of intestinal perforation in typhoid fever

Serum C-reactive protein concentrations were measured in 28 Nigerian patients with typhoid fever on presentation at hospital and at intervals thereafter. Five of the 28 (18%) were subsequently diagnosed as suffering from ileal perforation. These patients had concentrations of C-reactive protein during the first 24 h of admission which were significantly higher (mean = 229 mg/L) than those without perforation (mean = 91 mg/L). C-reactive protein may have a role in the prediction of early diagnosis of perforation in patients with typhoid fever.

Changing concepts in cancer prevention: limitations and implications for future research in environmental carcinogenesis

While the cause and nature of certain human cancers are known, definitive preventative guidelines still cannot be offered for many types of tumors. This is partly due to the inherent biostatistical and epidemiological limitations involved in the identification and interpretation of complex carcinogenic risk factors and potential low-risk hazards. Two divergent control strategies have emerged: (a) regulatory programs designed to control or eliminate minute quantities of pollutants in the ambient environment, based on fairly rigid quantitative risk assessment; (b) a biological research effort to understand the fundamental biological mechanisms with the objective of eventually manipulating or intervening in carcinogenesis through chemoprevention or therapy. Apart from more intensified effort on certain already recognized causal factors, current research indicates that the eliminatory approach will have little impact on the cancer burden and that the mechanistic approach, although difficult and slow, represents the most logical alternative. This will require long-term major investments in fundamental research and manpower. This biological approach, however, is largely ignored by the public and legislative bodies concerned with cancer control strategies, partly due to lack of formal input to appropriate national bodies by experts in chemical carcinogenesis. Informed scientists have an important role in ensuring that the public and legislative bodies are aware of current scientific views on carcinogenesis and the need to establish priorities in research.

Everything is a carcinogen?

The public has developed the impression that in an industrialized society environmental carcinogens are ubiquitous and that all chemical exposures, irrespective of the dose, influence carcinogenesis. Such impressions are influenced by many nonscientific considerations and often reflect insufficient knowledge of scientific data and methods. Such misconceptions are thus partly explained by the multistage nature of carcinogenesis, the absence of a clear understanding, and definition of the multiple factors which influence cancer induction. It is obvious that not all chemicals are carcinogenic and it is reasonable to accept that not all substances (including primary chemical carcinogens) that are found to enhance carcinogens in animals are necessarily carcinogenic to humans under conditions of usual human exposure.

Cancer risk factors in human studies

The historical developments leading to the acceptance of the influence of dietary and behavioral aspects of our life-style on cancer are reviewed. However, present information is usually insufficient to permit description of the complex mechanisms involved that are unlikely to yield to classical epidemiologic approaches alone. Better integrated laboratory epidemiologic studies are required that use more advanced nonintervention techniques. Progress may be slow in the identification of such factors in view of the many parameters involved, the absence of a single predominant or avoidable cause in many cancers, and the lack of adequately developed laboratory techniques for epidemiologic application.

Acute phase response of serum amyloid A protein and C reactive protein to the common cold and influenza

C reactive protein (CRP) and serum amyloid A protein (SAA) are sensitive and rapid acute phase reactants, and their measurement for monitoring inflammatory disease and assessing the prognosis in secondary amyloidosis is gaining widespread acceptance. The changes in these proteins in eight subjects suffering from natural colds, 15 subjects with experimentally induced colds (rhinoviruses E1, 3, 9, 14, or 31), and eight with experimentally induced influenza (A/Eng/40/83) were studied. SAA concentration increased in 21 of the 23 subjects with natural or experimental rhinovirus colds (mean increase 95 mg/l); CRP concentration increased in 11 (mean increase 11 mg/l). All subjects with influenza showed pronounced increases in SAA concentrations (mean increase 642 mg/l) while six showed increases in CRP concentration (mean increase 22 mg/l). All these increases were highly significant (p less than 0.001). Asymptomatic excretors of both rhinovirus and influenza virus showed significant increases in SAA concentration (p = 0.015 for rhinovirus and p less than 0.001 for influenza virus) but not in CRP concentration. No changes in SAA or CRP values were seen in 12 volunteers after challenge with saline. These observations suggest that caution is required in the interpretation of estimations of SAA concentration and that it may be too sensitive an acute phase protein for clinical use as its concentration may be raised in both trivial and asymptomatic viral infections.

The face of cancer worldwide

The overall incidence of cancer is much the same around the world, but specific rates often vary markedly from one population to another, even when those populations are genetically similar. Epidemiologic analysis of cancer patterns in advanced and underdeveloped countries indicates that, for the most part, they are associated with behavioral, cultural, and dietary factors.

Nutritional status, globulin titers, and parasitic infections of two populations of Tanzanian school children

Two schools in rural Tanzania were surveyed regarding the pupils' nutrition (weight and height), serum immunoglobulins (IgA, IgG, IgM, and IgE), autoantibodies, malaria antibodies, hepatitis B antigenemia, and fecal and urinary parasites. The survey attempted to quantify the relative importance of undernutrition and parasitic infestation in determining the serological abnormalities found. Of all the children surveyed 69% were undernourished (less than 80% of expected weight for age); 63% had fecal parasites and 38% had urinary schistosomiasis. Serum IgG and IgM concentrations were raised and the serum IgE concentration was strikingly raised (mean 4990IU/ml). Elevated serum IgE was associated with ascariasis. Autoantibodies were common but no autoimmune disease was detected. Notably there was a 35% prevalence of reticulin antibody. This reticulin antibody positivity correlated with increased malaria antibody concentrations. Reduced malaria antibody concentration was significantly associated with hepatitis B antigenemia. The study illustrates that parasites, notably malaria, are important determinants of the serum antibodies of children in the tropics and suggests that mild undernutrition has little effect.