The initiation of re-entrant cardiac arrhythmias is associated with increased dispersion of repolarisation, but the details are difficult to investigate either experimentally or clinically. We used a computational model of cardiac tissue to study systematically the association between action potential duration (APD) dispersion and susceptibility to re-entry.+ channel gKmax set to 0.004 mS mm-2. Within the central 40 × 40 mm region we introduced square regions with prolonged APD by reducing gKmax to between 0.001 and 0.003 mS mm-2. We varied (i) the spatial scale of these regions, (ii) the magnitude of gKmax in these regions, and (iii) cell-to-cell coupling.We simulated a 60 × 60 mm 2 D sheet of cardiac ventricular tissue using the Luo-Rudy phase 1 model, with maximal conductance of the KgKmax in regions with prolonged APD from 0.003 to 0.001 mS mm-2 increased APD dispersion from 22 to 70 ms, and the susceptible window from <1 to 56 ms. Decreasing cell-to-cell coupling by changing the diffusion coefficient from 0.2 to 0.05 mm2 ms-1 increased APD dispersion from 57 to 88 ms, and increased the susceptible window from 41 to 74 ms.Changing spatial scale from 5 to 20 mm increased APD dispersion from 49 to 102 ms, and the susceptible window from 31 to 86 ms. Decreasing We found a close association between increased APD dispersion and susceptibility to re-entrant arrhythmias, when APD dispersion is increased by larger spatial scale of heterogeneity, greater electrophysiological heterogeneity, and weaker cell-to-cell coupling. Cardiac disease remains an important cause of sudden death in the industrialised world, and in many cases the lethal events are the cardiac arrhythmias called ventricular tachycardia (VT) and ventricular fibrillation (VF). Spontaneous episodes of VT and VF occur in patients where cardiac disease or congenital abnormality has remodelled either the structure or function of cardiac cells and tissue. There is abundant experimental evidence to support the idea that VT and VF are sustained by re-entry ,2, but tSlow conduction and unidirectional block have long been known to facilitate re-entry , and exp-1 were associated with block and re-entry [Regional differences in repolarisation are often described as action potential duration (APD) dispersion. The difference between the longest and shortest observed APD is a conceptually simple and easily obtained quantity and has widely been used to measure APD dispersion, although other indices have been proposed . Some exre-entry ,19,20. Sre-entry ,21,22. T+ channel conductance between regions with short and long APD, and (iii) strength of cell-to-cell coupling.Computational models offer a powerful research tool for addressing these questions, because the properties of a virtual tissue can be controlled precisely and independently in a way that would be extremely difficult to achieve experimentally. The purpose of this study was therefore to investigate systematically how measured APD dispersion and vulnerability to re-entry in a computational model of ventricular tissue are related to: (i) the spatial scale of heterogeneity, (ii) the magnitude of differences in KWe simulated electrical activation in a 2 D isotropic monodomain virtual tissue Vm is membrane voltage, Cm specific membrane capacitance, D a diffusion coefficient and Iion current flow through the cell membrane per unit area. We used the Luo-Rudy phase 1 (LR1) model [Iion,where 1) model  to give INa, ICa  and IK are time and voltage dependent currents flowing through Na+, Ca2+, and K+ channels, IK1 a time-independent K+ current, IKp a plateau K+ current, and Ib a background current. We changed two parameters from the original Luo and Rudy paper [+ conductance from 0.23 mS mm-2 to 0.16 mS mm-2 as in the later version of the model [-2 to 0.0005 mS mm-2 to produce an APD comparable to that in the canine ventricle. We controlled repolarisation by varying maximum K+ conductance (gKmax) from the default value of 0.00282 mS mm-2 to a value between 0.001 mS mm-2 and 0.004 mS mm-2 (see below).where dy paper . We reduhe model , and we Cm to 0.001 μF mm-2, and set D to between 0.05 and 0.2 mm2 ms-1. We used an adaptive timestep of either 0.02 or 0.1 ms depending on the magnitude of dVm/dt at each grid point [2 ms-1 we obtained a conduction velocity (CV) for a stable plane wave of 0.56 m s-1, with a speedup of about two times and an error in CV of 2.5 % compared to computations with a fixed timestep of 0.01 ms. Simulations with smaller fixed and adaptive timesteps yielded plane waves with a comparable CV. Changing the space step to 0.25 mm and 0.15 mm resulted in a change of CV for a plane wave of <5 % compared to the CV computed with a space step of 0.2 mm. These findings indicated the stability of our numerical method.We solved equation 1 and the LR1 equations using an explicit Euler method, with both a lookup table of the voltage dependent parameters in the LR1 model, and an adaptive operator splitting technique . We applid point . With a gKmax. In each case a propagating action potential could be elicited with a minimum diastolic interval of about 10 ms, indicating that the refractory period was very close to the APD.Figure gKmax set to 0.004 mS mm-2. The central 40 × 40 mm region was heterogeneous, and was subdivided into squares. Within alternate squares gKmax was set to either 0.004 mS mm-2 or to a specific lower value (see below). Thus the virtual tissues had a border region with short APD, and a central heterogeneous region divided into a chequerboard with alternating squares of either short or long APD  of 0.003 mS mm-2. The diffusion coefficient in the whole virtual tissue was set to 0.1 mm2 ms-1.In our reference virtual tissue, the 40 × 40 mm heterogeneous region was divided into 16 squares giving heterogeneity with a spatial scale of 10 mm. In half of the 16 squares spatial scale of heterogeneity by changing the size of heterogeneity in the reference virtual tissue from 10 mm to 20 mm and 5 mm  at every grid point. We estimated APD dispersion during steady pacing with three measured that have been used in experimental studies [APDdiff). Second we measured the standard deviation of APD (APDSD) across the whole virtual tissue. Finally we measured the APD difference between each grid point and its neighbours 1 mm above, below, left and right, and determined the maximum value of measurements throughout the whole virtual tissue (maxLD) [Action potentials were initiated in each virtual tissue by holding the membrane voltage along one edge at 0 mV for 2 ms. We measured APD to 90% recovery (APD studies . First w (maxLD) .gKmax supported propagating plane waves following S1 stimulation along one edge. These propagating plane waves had a depolarising wavefront and a repolarising wave back both aligned parallel to the edge that was stimulated. A premature S2 stimulus delivered to the same edge as the S1 stimulus therefore resulted either in block or in a propagating plane wave.A spatially homogenous control virtual tissue with uniform block if the S2 stimulus failed to propagate, re-entry if the S2 stimulus elicited re-entry that completed more than one cycle, wavebreak if the S2 stimulus elicited a wave that broke but did not re-enter, or propagation if the S2 stimulus elicited a wave that propagated without wavebreak.In the heterogeneous virtual tissues the wave back was not a plane wave because some regions repolarised more quickly than others. A premature S2 stimulus could produce a wavefront that would encounter a mixture of recovered and refractory tissue, and hence elicit wavebreak and re-entry. We therefore assessed vulnerability to re-entry in the heterogeneous virtual tissues by delivering two S1 stimuli to one edge at 500 ms intervals, and then a premature S2 stimulus to the same edge. We varied the timing of the S2 stimulus in steps of 1 ms. The virtual tissue response was characterised as either susceptibility to re-entry, and to the range of S2 intervals as the width of the susceptible window.Vulnerability to re-entry is typically estimated by applying a local premature stimulus that interacts with repolarising tissue, and the vulnerable window is the range of stimulus strength and timing that elicits re-entry. In this study, we investigated the initiation of re-entry by S1 S2 stimulation from the same stimulus site, and we estimated the vulnerability of each virtual tissue to re-entry from the range of S2 intervals that resulted in either wavebreak or re-entry. To avoid confusion we refer to our estimate of vulnerability as + channel and conductance of the time independent K+ channel gK1.We made a preliminary investigation into two candidate mechanisms for reducing susceptibility, inactivation of the Na+ current to support a propagating wavefront [+ channels have not recovered from inactivation, then a propagating wave blocks and dissipates [+ channel inactivation is controlled by the j-gate in the LR1 model [+ channels from inactivation throughout the virtual tissue by multiplying the time constant of Na+ channel inactivation τj by 10 [Block of an action potential occurs if there is insufficient Naavefront ; when Nassipates . Na+ chaR1 model . We prolτj by 10 .+ current iK1 is a voltage dependent current that holds the membrane at its resting potential. It is activated during repolarisation and at rest, and is also activated close to the core of re-entrant waves [iK1 throughout the virtual tissue.The time independent Knt waves ,31. We i90 in variants of the virtual tissue during pacing at a cycle length of 500 ms from the bottom edge. The three columns show the effect of changing spatial scales  or re-entry (orange), and hence an increase in the width of the susceptible window The lower bound of the susceptible window where S2 was blocked depended on the refractory period of the border tissue with short APD, and was not greatly affected by changes in spatial scale, Δgkmax or strength of cell-to-cell coupling. The upper bound showed a similar trend to the measures of APD dispersion shown in Figure gkmax and weak cell-to-cell coupling associated with a wide susceptible window.Figure The virtual tissue with a spatial scale of 20 mm showed a different pattern of susceptibility compared to the others, with two ranges of S2 that initiated wavebreak and two ranges of S2 that initiated re-entry. This behaviour is illustrated in Figure APDdiff and reveals an approximately linear relationship. The correlation coefficient R2 = 0.99, which indicates a strong association between APDdiff and susceptibility. The interception of the line with the APDdiff axis also suggests that for the S1 S2 configuration used in this study, the susceptible window falls to zero for APD dispersion less than 20 ms. The association between the other measures of APD dispersion  effect on maximum and minimum APD, the width of the susceptible window was decreased from 56 ms to 39 ms. The lower bound of the susceptible window moved from 198 to 216 ms, reflecting an increase in the refractory period of the virtual tissue as well as more prominent conduction velocity restitution.Although prolonging τgK1 increased current flow across the membrane during repolarisation, shortening APD by about 10% and decreasing APDdiff from 70 ms to 49 ms. The width of the susceptible window was also reduced from 56 ms to 42 ms when gK1 was doubled. The lower bound of the susceptible window moved from 198 ms to 175 ms, as a result of the shorter APD.Doubling gkmax, and strength of cell-to-cell coupling on APD dispersion and susceptibility to re-entry. Wavebreaks and re-entry can be created in cardiac tissue when an activation wavefront encounters a gradient of recovery. Experimental studies have therefore found an association between increased APD dispersion and greater susceptibility to re-entry because a premature stimulus is more likely to be blocked in tissue with regions of prolonged APD. In this study we found that large spatial scale heterogeneity, large Δgkmax, and reduced strength of cell-to-cell coupling all increased both APD dispersion and susceptibility to re-entry. Tissue heterogeneities produce APD dispersion, and APD dispersion is modulated by electrotonic current flow [gkmax affected APD dispersion directly, whereas changing the strength of cell-to-cell coupling affected electrotonic current flow. This study indicates that each of these factors could be an important component in arrhythmogenesis, and that the susceptibility of a heterogenous tissue to re-entry can be estimated from simple measures of APD dispersion.In this study we have used a computational model of cardiac tissue to dissect out the effects of spatial scale, Δent flow . In thisgkmax and strength of cell-to-cell coupling in the experimental study are difficult to establish. Nevertheless the initiation of re-entry by block and retrograde activation in the region with prolonged APD followed a broadly similar pattern to our simulations, although the activation pathways in the experimental study were more complex, presumably due to anisotropic conduction in the rabbit ventricle. A decrease in strength of cell-to-cell coupling results in slowed conduction, and this is a common finding in tissue damaged by ischaemia, infarction [Although the spatial scale of heterogeneity has been identified as potentially important in other studies , there ifarction , and othfarction . Severalfarction ,35-37.Recent computational studies have addressed the influence of heterogeneous acetylcholine distribution on the vulnerability to and stability of re-entry in the atria ,32. The The dynamical behaviour of APD is recognised as important not only for the stability of re-entry  but alsoThe effect of heterogeneity on the stability of spiral waves has been investigated by Xie et al . This stNormal ventricular tissue is remarkably resistant to the initiation of re-entry, but this robustness is greatly reduced by actions that increase the spatial dispersion of refractoriness. In this computational study we have shown that regional differences in repolarisation have an interlinked effect not only on the initiation of re-entry but also on measures of APD dispersion. Measures of APD dispersion are valuable in clinical practice because they could provide an estimate of arrhythmia risk, and various indices have been developed in experimental studies . In our + channels from inactivation can be prolonged, or if the conductance of the iK1 channel can be increased. The effect of this kind of intervention in the intact heart may however be more complex. Other computational studies have shown that modifying the kinetics of the Na+ channel can have a pro-arrhythmic effect. Delaying recovery of Na+ channels from inactivation can increase the slope of the APD restitution curve and hence the likelihood of alternans and re-entry [+ channel conductance increases the vulnerable window [iK1 channel in experimental studies [iK1 channel conductance on susceptibility to re-entry investigated in the present study, it does highlight the potential importance of this channel for the mechanisms of re-entry.These preliminary investigations suggest that, in our model, susceptibility to re-entry could be reduced if recovery of Nare-entry , and rede window . Differe studies . AlthougThe influence of individual ion channel currents on the initiation and subsequent behaviour of re-entry is an important direction for future research, but will require more biophysically detailed cell models than the LR1 model used in this study.The electrical behaviour of cardiac tissue is complex, and depends on processes that act at tissue, cell, sub-cellular, and molecular levels. Computational models of electrical activation and conduction in the heart aim to simulate processes that are relevant to the research question, and simplifications are made accordingly. This study involved a large number of computations to establish susceptibility to re-entry, and so we chose to use a model that was a compromise between fidelity to real cardiac tissue and computational requirements.2+ storage and release have been developed [2+ handling may become heterogeneous in addition to APD, and so it is possible that susceptibility to re-entry could also be modified if this additional feature is taken into account.More detailed versions of the LR model and others incorporating a fuller description of ion channels, pumps, exchangers, as well as Caeveloped ,25,45,46In the present study we chose to use an idealised geometrical heterogeneity based on square regions because this approach allowed us to assess the initiation of re-entry under well controlled conditions. In real cardiac tissue we would expect the heterogeneities to be much more irregular in shape and gradient, and the conditions that favour re-entry to be dependent on the relative location of the heterogenous region and the stimulus site.The behaviour of re-entry in 3 D tissue is more complex than in 2 D, especially when the effects of rotational anisotropy and transmural differences in action potential shape and duration are taken into account . StudiesRHC conceived and designed the study, wrote the simulation code, and ran the simulations. AVH participated in the study design, and helped draft the manuscript. Both authors read and approved the final manuscript.Movie relating to Figure 5aClick here for fileMovie relating to Figure 5bClick here for fileMovie relating to Figure 5cClick here for fileMovie relating to Figure 7aClick here for fileMovie relating to Figure 7bClick here for fileMovie relating to Figure 7cClick here for file


Vif functions to counteract an anti-retroviral cellular factor in non-permissive cells named APOBEC3G. The current mechanism proposed for protection of the virus by HIV-1 Vif is to induce APOBEC3G degradation through a ubiquitination-dependent proteasomal pathway. However, a new study published in Retrovirology by Strebel and colleagues suggests that Vif-induced APOBEC3G destruction may not be required for Vif's virus-protective effect. Strebel and co-workers show that Vif and APOBEC3G can stably co-exist, and yet viruses produced under such conditions are fully infectious. This new result highlights the notion that depletion of APOBEC3G is not the sole protective mechanism of Vif and that additional mechanisms exerted by this protein can be envisioned which counteract APOBEC3G and enhance HIV infectivity.The viral infectivity factor, Vif, of human immunodeficiency virus type 1, HIV-1, has long been shown to promote viral replication  Retrovirology article [In contrast to most animal viruses, infection with the human and simian immunodeficiency viruses results in prolonged, continuous viral replication in the infected host. Remarkably, viral persistence is not thwarted by the presence of apparently vigorous, virus-specific immune responses. Several factors, including the evasion of an innate cellular anti-viral defense by HIV-1 as discussed in a recent  article . Interes article -5. Earli article ,6.APOBEC3G is a virion-encapsidated cellular protein that deaminates dC to dU in minus-strand viral cDNA during reverse transcription -10. The vif+ virus are not known; but, current observations are that APOBEC3G confers a major deleterious effect to the HIV-1 genome when the Vif protein is absent. Historically, Vif has been known to play a dramatically important role in HIV-1 infectivity [vif-defective virus can replicate in some permissive cells such as Jurkat and SupT1 cells, but cannot replicate in other non-permissive cells such as macrophages, primary human T cells, and some restrictive T cell lines [The effects of APOBEC3G and its G-to-A deaminase activity on the survival of wild type HIV-1 ectivity ,13. Vif ectivity -17. HIV-ll lines -20. For ll lines .Following on the heels of that initial observation, an enormous amount of effort emerged from several laboratories directed at elucidating how Vif mechanistically counteracts APOBEC3G in order to protect HIV-1 . These results strongly support a new mechanistic function of HIV-1 Vif protein, complementing the model where Vif counteracts the inhibitory effects of APOBEC3G by enhancing its degradation via ubiquitin-proteasome pathway  may indicate an alternative protective mechanism used by HIV-1 to eliminate innate cellular immunity. Nevertheless, we cannot exclude that HIV-1 uses Vif to exert multiple mechanisms to synergistically and more effectively inhibit the anti-viral activity of APOBEC3G.m pNL-A1 . Even thytoplasm ,46. If AIn conclusion, the existence of two different mechanisms may represent two faces of the same coin, with the common goal of inhibiting APOBEC3G's anti-viral activity. As is often the case with new findings, new questions are posed. The link between APOBEC3G's enzymatic function, its degradation pathway, and its incorporation into virions in the presence of Vif is certainly to require additional attention. Answers to these questions are likely to keep many of us busy for the foreseeable future.None declared.The abbreviations used are: HIV-1, human immunodeficiency virus, type 1; Vif, Viral Infectivity Factor; SIV, simian immunodeficiency virus; NC, nucleocapsid protein; APOBEC3G, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G; APOBEC3F, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3F PBMC, peripheral blood mononuclear cells; Cul5, Cullin type 5; SCF, skp1-cullin-F-box protein ligase.


PLoS Medicine, Ben Lopman and colleagues argue that although it is right to criticize the lack of evidence on unsafe medical injection, field data are hard to collect. They note that in the only published study addressing this issue, Kiwanuka and colleagues found no link between unsafe injections and HIV spread in rural Uganda. In an effort to “inform the debate” further, Lopman and colleagues looked at the association between HIV and unsafe injection practices in rural Zimbabwe.Of the 40 million people worldwide with HIV, 30 million live in the developing world. By far the worst hit region is sub-Saharan Africa, where nearly four million children have lost one or both parents to HIV/AIDS since 2000. Is heterosexual transmission the driving force behind the HIV epidemic in sub-Saharan Africa? In a controversial debate, some researchers have suggested that other factors such as unsafe medical injection practices may also be to blame, and that by overlooking, and even suppressing, analysis of this possible route of transmission, the current focus on preventing sexual transmission may be misguided. In this month's The team analyzed data from adults in Manicaland, a rural part of Zimbabwe, who were taking part in the Manicaland HIV/STD Prevention Study. In 1999 and 2000, eligible patients were tested for HIV and surveyed (86.7% were HIV negative at the start of the study), and were followed up three years later. The team collected survey data on injections in the patients, who were male and female adults aged 15 to 54 years old, and tested for an association between injection exposure and HIV infection. In 2002 and 2003, 505 of the men and 1,342 of the women, representing a 69.7% follow-up, were again interviewed and tested for HIV infection. Of these, 40% reported having had an injection or needle prick during the study period. A total of 67 patients developed HIV during the study; of these 13 (19%) said they had not had sex during the study period and 40 (60%) said they had not had an injection. The statistical analysis found no significant association between injections and HIV infection in men or women.Patients who had HIV when the study began did not have higher rates of injections. Instead, injections were highly associated with childbirth and pregnancy. But since HIV–positive women have reduced fertility, a reduction in the use of maternal services may partially explain why injections were not more common in these HIV-positive patients. In this study, the strongest predictor of HIV infection was symptoms of sexually transmitted disease.Despite problems of recall bias and under-reporting of sexual activity—a particularly difficult problem in studies in Africa—sexual behavior is consistently linked with HIV incidence. Where does this leave the debate over injections in Africa? Certainly, for this community, they do not seem to be a major source of HIV infection, and local policy-makers would therefore do best to concentrate on the prevention of sexually transmitted infections.


A 42 year-old male former semi-professional soccer player sustained a right lower extremity popliteal contusion during a soccer game. He was clinically diagnosed with a possible traumatic deep vein thrombosis (DVT), and sent for confirmatory tests. A duplex doppler ultrasound was positive for DVT, and the patient was admitted to hospital for anticoagulation . Upon discharge from hospital the patient continued oral warfarin anticoagulation (six months), and the use of compression stockings (nine months). He followed up with his family doctor at regular intervals for serial coagulation measurements, and ultrasound examinations. The patient's only identified major thrombotic risk factor was the traumatic injury. One year after the initial deep vein thrombosis (DVT) the patient returned to contact sport, however he continued to have intermittent symptoms of right lower leg pain and right knee effusion.Athletes can develop vascular injuries in a variety of contact and non-contact sports. Trauma is one of the most common causes of lower extremity deep vein thrombosis (DVT), however athletic injuries involving lower extremity traumatic DVT are seldom reported. This diagnosis and the associated risk factors must be considered during the initial physical examination. The primary method of radiological diagnosis of lower extremity DVT is a complete bilateral duplex sonography, which can be augmented by other methods such as evidence-based risk factor analysis. Antithrombotic medication is the current standard of treatment for DVT.    Acute thrombolytic treatment has demonstrated an improved therapeutic efficacy, and a decrease in post-DVT symptoms.There is a lack of scientific literature concerning the return to sport protocol following a DVT event. Athletic individuals who desire to return to sport after a DVT need to be fully informed about their treatment and risk of reoccurrence, so that appropriate decisions can be made. Athletes are susceptible to a variety of vascular injuries, secondary to either repetitive motion, or high-speed collisions . The difth, 2003 in the emergency department, with the chief complaint of right leg pain. The patient had been playing soccer 10 days prior to this visit, and recalled a traumatic "tackle" injury to the posterior area of his right lower extremity. He denied experiencing any sensation of tearing or popping in the right knee during the index trauma, and was able to complete the game with only minor discomfort. On day 3 post-injury the patient noted severe pain in his knee and calf with ambulation. The patient visited his primary doctor on post-injury day 8 and was diagnosed with a right lower extremity soft tissue injury. A right lower extremity echo-doppler ultrasound (US), and a semi-quantitative D-dimer automated latex procedure were ordered to rule out a vascular disorder. The US investigation demonstrated a DVT in the distal femoral, popliteal, and distal calf veins, with a heterogenous mass  without a doppler signal in the right popliteal fossa. The D-dimer result was also positive for a suspected thrombosis . The patient was instructed by his physician to proceed immediately to the emergency department for further evaluation and treatment.A 42 year old Polish born male former semi-professional soccer player was seen on May 16The past medical and family history of the patient was non-contributory for a history of thrombophilia or other thrombotic major risk factors. The patient had a remote (11 years old) surgical history of a right-sided inguinal hernia that could have created scar tissue contributing to vascular obstruction and stasis. The initial emergency department examination demonstrated an exquisitely tender right calf with a 3 cm difference in mid-calf girth ; a 1+ right knee supra patellar effusion; and a palpable popliteal mass with visible ecchymosis. Laboratory tests  were negative for metabolic, hematological or familial abnormalities. A repeat US investigation confirmed the results of the previous outpatient results. The patient was anticoagulated simultaneously with unfractionated heparin and Warfarin sulfate. A multiview plain film x-ray examination of the right lower extremity demonstrated no fracture, dislocation, or bony mass.A magnetic resonance image (MRI) of the right knee was done several days after admission, to verify a torn right knee meniscal cartilage that had been previously diagnosed. The official MRI radiological report included a small free-edge tear of the posterior horn root junction of the lateral meniscus, chondromalasia , and a moderate joint effusion with a bursal cyst or dilated semimembranous-gastronemius bursa.Anticoagulation was achieved on day 6 of the patient's hospitalization. He was discharged on 5 mg of warfarin per day, with instructions to continue the use of compression stockings. The patient was also advised to follow up with his primary physician for regular monitoring, and to avoid contact or collision activities during anticoagulation.The patient was maintained on warfarin for six months, with weekly physician monitoring  for the first three months post-injury. The monitoring interval was changed to once per month for the remainder of the treatment period. Hematologic investigations  were obtained three months post injury. There were no contributory thrombophilic factors found in these investigations. Laboratory levels of Protein C activity 22% (range = 70–140%), Protein S activity 48% (range = 75–140%), INR 2.57 (range = 0.88–1.12), and PT 27.5 sec (range = 9.6–12.0 sec); APTT 38.5 sec (range = 23.4–35.4 sec) were found to be appropriately reactive to the anticoagulant therapy.The patient underwent two arthrocentesis procedures to remove small amounts of serous fluid from the joint, and each time was injected with a lidocaine/corticosteroid combination. US examinations after the hospitalization period failed to demonstrate a recurrence or new onset of DVT, however residual echogenic material characteristic of a chronic thrombus was demonstrated in the popliteal vein. Compression stocking use was maintained after hospital discharge, and was discontinued after nine months. The patient returned to soccer after anticoagulation, with a full understanding of his increased risk of DVT recurrence.One-year post injury the patient continued to suffer from intermittent right lower extremity discomfort and swelling often unrelated to activity. An elective arthroscopy was recently performed on the patient's right knee to investigate his long-standing meniscal disruption and effusion. The arthroscopy demonstrated several areas of arthrosis , and a torn lateral meniscus. Appropriate partial lateral menisectomy and debridement, and chondroplasty of the areas of arthrosis were preformed. An arthroscopic examination of the posterior compartment demonstrated a small cleft-like area just medial to the semimembranosis where the Baker's cyst likely originated. The patient returned to the orthopedist one week post-op with a large (150 cc's) hemarthrosis that was aspirated from the knee. He was requested to follow-up in one month for re-evaluation.This case study illustrates the importance of considering deep vein thrombosis in the diagnosis of sport-related extremity trauma. DVT is classically related to venous stasis, intimal injury, and coagulation diathesis (Virchow's triad). The estimated incidence of DVT from all causes is 0.5 to 1.6 per 1000 persons per year, and may be an underestimation due to the number of DVT that are asymptomatic .Standard risk factors for DVT are immobilization, pregnancy, recent surgery (particularly orthopedic), malignancy, older age, smoking, coagulation deficits or hypercoagulable states, connective tissue disorders, sex steroid administration, severe dehydration, and major trauma. Bates et al.  presenteCoagulation diathesis through congenital or acquired thrombophilia may promote coagulation . CoagulaThe testing for hypercoagulable states in an individual after a single episode of thrombosis is a costly, yet routine procedure in many centers. The common assumption that an identified presence of a thrombophilic abnormality increases the risk of recurrence, and justifies prolonged therapy is without clear supportive evidence. A review of the current literature concerning the treatment of individuals with coagulation deficits concludes that there is no clear evidence that modifying treatment because of an identified hypercoaguable state alters the outcome, or that more intensive therapy is required in patients with laboratory evidence of thrombophillia .Exercise is thought to act as a protective mechanism against thrombosis, due to the controlled balance between the exercise activated coagulation and fibrinolytic pathways . Upper eLower extremity DVT with a traumatic sporting injury in otherwise healthy active adults is seldom mentioned in the medical literature -29. ThisThe popliteal, posterior tibial and peroneal veins are susceptible to intimal trauma by the sudden hyperextension and torsion that the lower extremity experiences in a soccer "kick" or "tackle" motion. The popliteal arteries and veins are susceptible to direct, sheering, and muscular compressive forces due to their anatomical position, especially with rapid knee hyperextension or anterior dislocation ,22.The literature demonstrates the importance and efficacy of a complete bilateral duplex sonography as the primary method of DVT diagnostic investigation . US findAnticoagulation is effective in preventing DVT propagation and PE, but has no chemical fibrinolytic activity. This type of therapy allows for intrinsic fibrinolysis to occur. Radiographically demonstrable clot lysis occurs in only 50% of anticoagulated patients, and the incidence of complete resolution is less than 5%. Intrinsic fibrinolysis that occurs slowly does not preserve the function of the venous valves, which become fibrotic and fixed after a few weeks of being trapped in clot .The symptoms experienced by individuals without complete clot resolution include heavy or achy legs, edema, throbbing paresthesia, purities, numbness, stiffness, and difficulty standing or ambulating. Postthrombotic syndrome (PTS) is characterized by brawny edema of the leg, stasis dermatitis, hyperpigmentation, induration, ulceration and chronic leg pain. This syndrome is associated with an extraordinary level of chronic pain and disability, and approximately 40% of the total cost of treating DVT is spent on PTS .Zeigler et al.  investigThere is growing evidence that the early lysis provided by thrombolytic therapy is more likely to preserve valve function, decreasing the likelihood of DVT recurrence, and the occurrence of PTS ,39. ReceThe general knowledge concerning quality of life and burden of illness in patients with persistent post-DVT symptoms is limited. This issue is especially important to the athletic patient, as participation in sport is usually an extremely important component of quality of life. For routine monitoring of outcomes in chronic venous disorders there are questionnaires that are available ,41. HednThe athlete's primary concern upon the initial DVT diagnosis is return to play. The issue of return to sport after a lower extremity DVTs has only been addressed only once in the literature concerning return to non-contact sport . GeneralAn athlete who wants to return to a contact or collision sport should be informed of the possible increased risk of recurrent DVT that he or she may face, above the current estimates derived from the general population. There is no current evidence in the literature that investigates the specific risk factor of a traumatic collision, and the recurrence of a DVT. This lack of evidence suggests that the patient and physician should work together to make an informed return to play decision involving the patient's current individual risk profile, the likelihood of DVT recurrence, athletic goals, and the perceived importance of the particular sport to quality of life.The potential limitations of this case study include the lack of testing for prothrobin mutation, and fibrynolitic parameters .The author(s) declare that they have no competing interests.PE developed, researched, wrote and revised the case study; RU assisted in study development and manuscript revision; DM assisted in manuscript development and revision; HJ assisted in manuscript development and revision.


The objective of this study was to develop simultaneously a new questionnaire, the Pediatric GERD Caregiver Impact Questionnaire (PGCIQ), in American English and American Spanish in order to elucidate the impact of caring for a child with GERD.Two focus group discussions were conducted in American English and American Spanish to develop a relevant conceptual model. Focus group participants were the primary caregivers of children with GERD (newborn through 12 years of age). Participant responses were qualitatively analyzed to identify potential differences in caregiver perspectives by the caregiver's language, socio-economic status and demographic profile as well as the child's age and disease severity level. Items in the PGCIQ were generated simultaneously in English and Spanish by reviewing results of qualitative analysis from focus groups in each language. The PGCIQ was finalized in both languages after testing content validity and conducting an in-depth translatability assessment.Analysis of focus group comments resulted in the development of a first draft questionnaire consisting of 58 items in 10 domains. Content validity testing and an in-depth translatability assessment resulted in wording modification of 37 items, deletion of 14 items and the addition of a domain with five items. Feedback from the content validity testing interviews indicated that the instrument is conceptually relevant in both American English and American Spanish, clear, comprehensive and easy to complete within 10 minutes. The final version of the PGCIQ contains 49 items assessing ten domains. An optional module with nine items is available for investigative research purposes and for use only at baseline.The PGCIQ was developed using simultaneous item generation, a process that allows for consideration of concept relevance in all stages of development and in all languages being developed. The PGCIQ is the first questionnaire to document the multidimensional impact of caring for an infant or young child with GERD. Linguistic adaptation of the PGCIQ in multiple languages is ongoing. A validation study of the PGCIQ is needed to examine its psychometric properties, further refine the items and develop an appropriate scoring model. Gastric reflux of short duration is a normal physiological event for all infants less than six to seven weeks old. When gastric reflux occurs more frequently and past the age of seven weeks, it becomes a clinically significant problem that is diagnosed as pediatric gastroesophageal reflux disease (GERD). Symptoms of pediatric GERD include pain, irritability, frequent spitting-up or vomiting, constant or sudden crying, poor sleep habits and frequent waking. At present, these symptoms represent a clinically significant problem for one of every 500 infants between the ages of six weeks and 18 months .The prevalence of symptoms consistent with pediatric GERD varies with age and depends upon the type of symptoms. When referring solely to regurgitation symptoms, over 80% of children experience spontaneous remission by age 18 months . In compMany health care professionals (HCPs) specializing in the treatment of GERD feel that published prevalence rates underestimate the extent of the condition ,7. InterIn addition to having serious consequences for infants and young children, reports from parent advocacy groups suggest that untreated or ineffectively treated pediatric GERD exerts a substantial negative impact on the life of the child's primary caregiver . CaregivThe current study had two objectives related to the assessment of the impact of pediatric GERD on the caregiver's daily life. The first objective was to determine if there was an existing instrument suitable for measuring the impact of caring for an infant or child with GERD. If no instrument could be identified, the second objective was to develop an instrument suitable to quantify the impact of pediatric GERD on caregivers, thereby providing a means to improve public awareness of the issue.A focused literature review was conducted to determine if a caregiver-reported outcome measure that assesses the impact of caring for an infant or child with GERD had been developed. This review included a search of commercial and Mapi Values in-house medical databases of published literature from 1990 to the present in order to identify available instruments and studies relevant to caregiver burden in pediatric GERD. Additionally, the review examined whether generic quality of life measures had been previously applied to the assessment of the impact of caring for a pediatric GERD patient. The literature review uncovered numerous instruments developed for caregivers of adult, elderly or terminally ill patients  , evaluatThe "Pediatric GERD Caregiver Impact Questionnaire" (PGCIQ) was developed in American English and American Spanish to address the need for an instrument to assess the impact of caring for a child with GERD. This instrument was developed for use in observational studies and multi-national clinical trials to systematically assess and document the physical, psychosocial, psychological and financial impact of caring for pediatric GERD patients. In addition, items in the PGCIQ were specifically developed to capture changes in caregiver burden in response to successful treatment. This instrument will allow documentation of the impact of caring for a child with GERD and provide evidence to increase public and physician awareness of the condition.The PGCIQ was developed simultaneously in American English and American Spanish to accommodate the rapidly changing population composition of the United States (U.S.). The U.S. Hispanic population grew by 61% from 1970 to 1980 and by another 53% in the following 10 years . BetweenAlthough the questionnaire was initially developed in American English and American Spanish, it was designed to be suitable for cross-cultural and linguistic adaptation into multiple languages. Thus, the PGCIQ was developed to provide valuable information in multi-national clinical evaluations regarding the value of different GERD treatments from the caregiver's perspective. Information obtained from the PGCIQ can be used to inform and educate health care providers and payers about the needs of caregivers of pediatric GERD patients.The development of the PGCIQ followed the methodology of simultaneous questionnaire development. This process was selected to reduce the risk of systematic measurement error at the item level  and ensure that construct bias, which occurs when the construct is measured, was identical across all developed language versions. When combining this methodology with a translatability assessment conducted by linguistic experts, the procedure was intended to yield an "optimal" measure for adaptation of the American English version into different cultures. Additionally, the process aimed to produce a measure that was less susceptible to cultural differences than a questionnaire developed in one language and followed by translation into other languages .Participants were recruited by pediatric gastroenterologists and pediatricians. The primary caregivers included in the discussions were 18 years or older and were caring for children (newborn to 12 years of age) who were either newly diagnosed with GERD or seeking treatment for a new episode of GERD after a period without treatment. Diagnoses of GERD required that children present with common clinical manifestations of GERD. Neonates and young babies were required to have chronic regurgitation, most commonly demonstrated by vomiting. In young children, diagnosis was confirmed by physical discomfort that manifested as prolonged crying, fussing, arching, or refusal of feedings. As well, all children three months or older were required to have symptoms of GERD requiring acid suppressive therapy.Caregivers were excluded if their child had a history of acute life-threatening events due to manifestations of GERD or a severe unstable illness that could exacerbate caregiver burden. In order to optimize the relevance of the instrument across a wide range of age groups, the study authors attempted to achieve an equal distribution of children within three groups: premature infants to three months, four to 11 months and 12 months to 12 years. Across all three groups, participant eligibility was confirmed by case report forms completed by the treating physician.Four focus group discussions, two in American English and two in American Spanish, were conducted to elicit issues relevant to caring for a child with GERD. For each language group, discussions were conducted on the East and West Coasts to ensure adequate representation of Mexicans, Puerto Ricans and Cubans, the three largest groups of Spanish-speaking Americans currently residing in the US .Each two-hour focus group was conducted using a structured focus group discussion guide that was developed in American English and linguistically adapted into American Spanish. American English and American Spanish focus groups were facilitated by two female researchers both living in the U.S. The native Spanish speaker was from Ecuador. Focus group moderators received identical, in-depth training from Mapi Values, and all focus groups were videotaped to ensure adherence to the discussion guide. Caregivers were asked to discuss how caring for their child has impacted their lives in the following areas: daily activities, social and family life, emotional and physical functioning and financial well-being. At the start of each focus group discussion, caregivers completed a 48-item GERD Caregiver Informational Survey, developed for this study, which contained questions about the caregiver's and child's demographic, socioeconomic and clinical profile.Qualitative analysis of the focus group discussions was conducted separately for each language group. This analysis included a comprehensive review of verbatim transcripts by native speaking researchers who also conducted the focus group discussions. Participants' comments were coded to highlight key concepts and psychosocial correlates. Coded comments were subsequently grouped together to elicit the domains and issues important to caregivers. These domains and correlates provided the framework of the conceptual model for questionnaire development Figure .Following creation of a conceptual model, global concepts within each language group were compared to evaluate similarities and differences in caregiver perspectives. In addition, responses were evaluated to identify potential differences by the child's developmental stage, severity of disease, socio-economic status and demographic profile. Participants' verbatim quotes from each language group were then consolidated within the common domains.Items were simultaneously generated in American English and American Spanish after consolidating caregivers' verbatim comments. For each item, American English and American Spanish speaking interviewers discussed relevant concepts identified from the focus group discussions and agreed upon conceptually equivalent wording. This process ensured that each item in the questionnaire was pertinent to caregivers in both language groups and formed the basis for Version 1 of the questionnaire.A panel of linguistic experts conducted a translatability assessment of the PGCIQ to finalize Version 1 of the PGCIQ. The questionnaire was evaluated for its cultural adaptability and translatability in all potential target languages to ensure the cultural equivalence of items. Additionally, this process was used to limit the threat of bias in all current and potential target languages. Items identified as irrelevant for future target languages were considered for deletion or modification in the English and Spanish versions.Content validity interviews were conducted by the native speaking researchers who also conducted the focus group discussions. Researchers interviewed caregivers to assess the ease of comprehension, clarity, cultural equivalence and relevance of the first version of the PGCIQ. Participants were recruited following the same methods and criteria as for the focus group discussions. The interviews aimed to assess the clarity, comprehension and appropriateness of all instructions, questionnaire items and response scales.Interviews were transcribed verbatim in the participants' native language. Each transcript was comprehensively reviewed, analyzed and coded to highlight caregiver impressions of Version 1 of the PGCIQ. Coded comments were subsequently grouped together to elicit the caregivers' feedback by item. Items were considered for modification if more than one caregiver in either language had difficulties with or suggestions for the item.The interview results from each language group were analyzed separately and later compared for potential differences. In addition, caregiver responses were evaluated for potential differences by the child's developmental stage, severity of disease, socio-economic status and demographic profile. If an item was identified during content validity testing as potentially problematic, the item was reviewed and simultaneously modified by interviewers in both languages. If an item was problematic in at least one of the languages, the interviewers reviewed the caregivers' verbatim suggestions and attempted to agree upon a conceptually equivalent modification. If no suitable wording could capture the same concept in both languages, the item was deleted from the questionnaire.The final version of the questionnaire aimed to be relevant to caregivers of pediatric GERD patients, conceptually equivalent in American English and American Spanish, free from bias or jargon and easy to understand, interpret and complete within 10–15 minutes. The final version of the questionnaire was also developed to be appropriate for administration for a fifth grade literacy level, as confirmed by a Flesch-Kincaid Grade level test  and lingTwenty-seven caregivers, 12 American English-speaking and 15 American Spanish-speaking, participated in the focus group discussions. The final distribution of interview participants by geographic region was East Coast English (n = 7), West Coast English (n = 6), East Coast Spanish (n = 5) and West Coast Spanish (n = 9). The average age of focus group participants was 37 years of age with a range of 18 to 64 years of age. The participants were predominantly female (89%), married (81%), living with their spouse and children (89%) and recipients of a high school diploma (81%). The fact that participants were primarily female reflects the composition of the population of primary caregivers seen by the investigators (referring physicians). Moreover, the study investigators attributed the fewer numbers of single and divorced caregivers in the discussion groups to difficulties in taking time off work. Analysis of the caregiver characteristics also revealed differences by language group. Relative to Spanish-speaking participants, a greater proportion of English-speaking respondents were female (100% vs. 80%) and married (100% vs. 67%). Table The children in this study were primarily female (52%) and their average age was 2.8 years, with a range of six months to eleven years. The average age was determined after excluding an outlier (12 year-olds) from the calculation. In terms of the target age groups, 8% of the sample population was premature up to three month-old infants; 33% were four month to 12 month-old infants; and 55% were 12 month to 12 year-old children. In total, 81% of the children were three years-old or younger, with only five of the children over the age of three. The majority of this sample consisted of children under the age of three years. The age range of this population was consistent with the literature which indicated that the prevalence of GERD symptoms significantly declines with age, with less than 30% of GERD cases persisting past three years of age .According to caregivers' ratings, their children were primarily in very good (26%), good (26%) or fair health (26%). Analysis of additional clinical measures revealed significant differences in the children's health by language group, with Spanish-speakers reporting more hours of fussiness per day, emergency room visits and hospitalizations. Table Qualitative analysis of the focus group discussion results revealed nine key concepts relevant to caregivers of pediatric GERD patients: experiences related to GERD diagnosis, taking care of the child, daily activities, emotional well-being, household expenses, physical health, social life, relationships, and employment prior to and after GERD diagnosis. Each key concept is discussed in the following sections.Caregivers recalled feelings of fear, helplessness and guilt associated with the onset of their children's GERD symptoms. Many of these feelings were discussed in the context of negative interactions with HCPs. Caregivers shared stories about their struggle to get doctor appointments or referrals and being told that their children's symptoms were "normal" or that they were "overreacting" or "paranoid." These experiences appeared to be particularly stressful for the Spanish-speaking caregivers. In several cases, Spanish-speaking caregivers stayed with their physicians even though they received inadequate medical attention due to their lack of comfort with the U.S. health system. Thus, their children tended to be diagnosed at an older age than children of English-speakers resulting in elevated feelings of fear, helplessness and guilt. Although caregivers stressed the trauma they experienced in order to obtain their child's diagnosis, this experience did not appear to be change once the child had received an accurate GERD diagnosis. Therefore, this domain will most likely not be affected by treatment and therefore, has been included as optional.Caregivers discussed four unique parenting issues related to taking care of a child with GERD: using special feeding techniques, putting the child to bed safely, disciplining the child and finding a reliable childcare provider. First, caregivers of children under four years of age discussed the need to use special feeding techniques. These caregivers commented that they needed to feed their children "small portions," feed them "constantly" and prepare special meals or formulas. Second, caregivers of infants reported adopting unique bedtime routines. These caregivers used equipment such as wedges, car seats, pillows and monitors to put their children to bed safely. Third, caregivers of children over the age of four cited discipline as a challenging issue. Several caregivers recalled emotional tales of disciplining their children for throwing up "on purpose," while others feared that their children would spit up every time they were "yelled at" or "punished." Finally, virtually all of the caregivers cited childcare as a major concern. Most caregivers were unwilling or unable to find childcare providers capable of handling their children's special needs. Even those caregivers who found suitable care providers experienced a sense of distress due to concerns that others would not care for their child adequately. For example, one caregiver stated "No one else is going to give your child the attention [he/she] needs".The caregivers cited three daily activities that were significantly impaired by their children's GERD: mealtimes, housework and bathing. Concerning mealtimes, the caregivers shared stories about spending time "preparing multiple meals" for the family , lacking time to "sit down and eat" and having to eat cereal, frozen meals or take-out for dinner multiple evenings in a row. With regard to housework, the caregivers shared anecdotes about having to do laundry "every day," "constantly cleaning the carpet" and putting plastic covers over the furniture to protect it from their children's spit-up or vomit. Finally, the caregivers recalled stories about not having time to bathe, struggling to shower while holding the child and feeling too tired to get dressed. Limitations in these three activities appeared to be most pertinent among caregivers of infants and caregivers of children with more severe GERD symptoms.Caring for a child with GERD had a major impact on the caregivers' emotional well-being. The caregivers mentioned a myriad of feelings including fear, worry, grief and depression. The lingering feelings of fear experienced by caregivers most frequently pertained to the possibility that their children might choke and stop breathing. These feelings of fear were reported primarily by caregivers of infants. Feelings of worry were experienced by caregivers of all age groups and predominantly focused on the child's "failure to thrive." These feelings of worry were particularly burdensome for caregivers of children with severe GERD who experienced substantial weight loss and significant developmental delays.Two specific differences between language groups were found in this domain. English-speaking caregivers mentioned feelings of guilt for "disliking" or "not wanting" their children and feelings of envy upon seeing other "healthy babies." In contrast, Spanish-speakers explained that it was a "given" that caregivers would be close to their children and that they did not experience the feeling of "disliking" their child.Caregivers discussed incurring additional expenses for a variety of products and services related to caring for their children including doctor/hospital bills, special infant formula(s), medicine, laundry, childcare, new or replaced furniture, new or replaced carpets, cleaning supplies and special equipment designed for managing GERD . During the focus group discussions, the majority of caregivers spontaneously provided information related to their employment and income level when discussing the financial impact of caring for their children. Where possible, this information was noted and recorded by the moderators for analysis. Additionally, the caregivers were asked information about their insurance coverage and typical expenses in the Caregiver Informational Survey. Analysis of these data indicated that the caregivers' expenses did not differ by their socio-economic status or language group. However, caregivers from lower income households appeared to be more greatly impacted by their additional household expenses and reported greater financial strain.The majority of caregivers indicated that their physical health had declined since their children first exhibited symptoms. Common terms used by the caregivers to describe the state of their physical health were "tired," "exhausted," "stressed out" and "distracted." In addition, the caregivers shared numerous stories about carrying their infants all day, sleeping in shifts with their spouses and developing physical ailments such as migraines and skin conditions due to the strain of caring for a child with GERD. These physical health challenges seemed to be particularly burdensome for caregivers of children with more severe cases of GERD.Caregivers reported reduced social interactions outside of the home and increased social isolation due to their children's GERD. Numerous caregivers commented that they preferred to "stay at home" due to the embarrassment of dealing with their children's constant "vomiting" and "screaming" in public and the emotional strain of seeing healthy babies of the same age as their children. For several caregivers, social isolation was exacerbated by difficulties experienced while talking on the telephone due to their children's "vomiting", "screaming" and need for attention. Issues of social isolation appeared to be most relevant for caregivers of younger infants and caregivers of children with more severe symptoms.Caregivers described how caring for their child's GERD affected their relationships with their spouse/partner, relatives, other child(ren) in the family, and their child with GERD. Discussions about the caregiver's relationship with their spouse/partner focused upon the tension experienced between the couple jointly caring for a child with GERD. Tension was often attributed to disagreements over the child's medical care, reduced personal time, reduced desire for physical intimacy and decreased communication. Comments about their relationships with relatives emphasized feelings of frustration with family members who "just don't get it," "complain so much" and "always judge." Remarks about their relationships with other children in the family reflected reduced time to dedicate to the siblings of the GERD patient. Some caregivers confessed that due to the attention required by their child with GERD, they were "less patient," more "demanding" and more "neglecting" of their other children. Finally, stories about the impact on the bond between the child with GERD and the primary caregiver reflected a dual-directional relationship. In some cases, the child's illness seemed to weaken the bond with the primary caregiver, whereas the illness appeared to strengthen the bond in other instances. No major differences were revealed in the impact on these four relationships by language, age, socio-economic or symptom severity group.The impact of caring for a child with GERD on an individual's employment was primarily dependent on the caregiver's employment situation prior to the child's diagnosis. The caregivers who were previously employed mentioned a number of ways that caring for a child with GERD affected their paid employment including: changes in work schedules, ability to take enough time off to care for their child, reduced productivity and changes in long-term career goals. In order to provide sufficient care for their children, many of the caregivers changed their work schedule by leaving their jobs altogether, switching jobs or cutting back their hours. Moreover, several caregivers took more paid or unpaid vacation time in order to take their children to doctors' appointments, share the burden of care with their spouses or provide more attention to their children. Employed caregivers also described indirect costs in terms of reduced productivity and inability to concentrate at work. Many of those caregivers who were not employed prior to the child's diagnosis reported altering or sacrificing their career plans to ensure they had enough time to devote to the child with GERD. The aforementioned employment issues appeared to be relevant to caregivers across language groups, age groups and symptom severity levels. Overall, however, the employment issues appeared to be especially pertinent for individuals from low-income households, many of whom worked in hourly rather than salaried positions.Item generation based on nine identified areas and the caregivers' verbatim responses resulted in 10 domains with a total of 58 items that were simultaneously generated in American English and American Spanish. The first draft assessed the following areas: experiences related to diagnosis, caring for the child, daily activities, emotional well-being, physical health, social life, relationships, household expenses and employment prior to onset of GERD and current employment.The domain assessing the caregivers experiences related to diagnosis was developed for baseline use only. This domain contains six items with "yes" and "no" response options and has a recall period of present time. Issues about employment were divided into two domains pertaining to the time before the child's diagnosis as well as the current time period in order to quantify how the direct and indirect costs associated with caring for a child with GERD change in response to treatment.With the exception of four domains , all questions in the remaining domains have ordinal scales evaluating intensity and frequency. These questions are phrased in the first person, for example: "During the last two weeks, I needed to prepare special meals or formulas for my child." The response format, a 5-point Likert scale was chosen, as the upper limit of an individual's capacity for discriminate judgments has been shown to be near seven (plus or minus two) . PreviouThe nine core domains and one optional domain in the first version of the PGCIQ were selected to correspond with the key themes identified from the focus group discussions. To ensure cultural equivalence of items, only those concepts that had been identified in both language groups served as the basis for generating items. Considering that 80% of caregivers had children under the age of three, item generation was predominantly based upon verbatim comments elicited by caregivers of infants and young children.In the item generation focus group discussions, over 80% of the caregivers had children aged three years or younger. Specific concepts that were noted in the focus group discussions as relevant to caregivers of older children and adolescents, but not to caregivers of infants or toddlers, included discipline issues, concern about the child's emotional well-being and concern about the child's academic development and self-esteem. In contrast, concepts that were relevant to caregivers of infants and toddlers, but not to caregivers of older children or adolescents, included the need to feed the child frequently, feed the child small portions and spend a significant amount of time feeding the child. In general, infants and toddlers also seemed to require more constant one-on-one attention, thereby exerting a greater impact on the caregivers' daily activities, social functioning and family lives.The PGCIQ was formulated in caregivers with a range of socio-economic and educational backgrounds. In general, all domains were relevant to caregivers across socio-demographic groups. However, the "employment" and "household expenses" domains appeared more relevant to caregivers of lower economic and educational status due to a higher prevalence of hourly wage earners. Employees working for hourly wages reported greater difficulties getting time off from work to care for their child, less coworker understanding, more financial strain and more pressure to remain in positions they did not enjoy than employees who were salaried. Those in lower income households also struggled more with additional household expenses due to the child's GERD and were more likely to report they could not afford products or services  to improve their children's health.The focus group discussions were conducted in American English and American Spanish. All domains appeared to be relevant to both language groups. Specific issues that were more relevant to the English-speaking groups included experiencing feelings of "envy," feelings of guilt for "disliking the child" and feeling "bonded with the child with GERD." In contrast, employment challenges and issues of tension, reduced intimacy and communication in the partner relationship appeared to be more relevant to the Spanish-speaking groups. Relative to the English-speakers, the Spanish-speakers also voiced the following unique challenges: more financial strain, more pressure to be an "ideal" parent, more difficulty getting attention from English-speaking doctors, less understanding from co-workers and less access to information about GERD.The results of the in-depth translatability assessment revealed that 16 of 58 items were potentially problematic for future adaptation of the PGCIQ into other languages. These 16 items were reviewed by native speakers. Four of the items were deleted and 12 of the items were modified to improve the cultural adaptability of the PGCIQ. The modified items were flagged for further testing in content validity interviews.Version 1 of PGCIQ was tested in twenty caregivers, 10 English-speaking and 10 Spanish-speaking, who agreed to participate in content validity testing interviews. The final distribution of interview participants by geographic region was East Coast English (n = 4), West Coast English (n = 6), East Coast Spanish (n = 3) and West Coast Spanish (n = 7). The characteristics of the interview population were similar to those of the focus group population. The average age of the participants was 38 years with a range from 24 to 79 years. The majority of the participants were female (70%), married (75%), living with their spouse and children (70%) and recipients of a high school degree (75%). These characteristics resemble those of the focus group population and favor the experiences of married females. Table The distribution of children was 45% female and 40% male. An additional 15% of the gender data was missing and is not included in these figures. The average age of the population was 2.3 years, with a range from 0.33 to 10.5 years. As noted, the majority of comments used for item generation of Version 1 pertained to infants and toddlers under the age of three years. Thus, an attempt was made to test the relevance of the PGCIQ in caregivers of older children during the content validity interviews. Despite attempts to recruit caregivers of older children, the final age distribution was skewed towards children 12 months-old and younger. Premature through three month-old infants composed 17%, four month-old to 12 month-old infants composed 56% and 12 month-old through 12 year-old children composed 28% of the final distribution. Similar to the age distribution of the focus group discussions, 85% of the interview participants cared for children through the age of three, with only three of the 20 caregivers having children over three years. Table Overall, the respondents had positive impressions of the PGCIQ and described it as "easy to understand" and "easy to answer." The respondents were also satisfied with the recall period, length and the format of the questionnaire. The average time of completion was eight minutes, with a range from five to 15 minutes.The caregivers suggested a number of revisions to improve clarity. These suggestions, combined with the results of the in-depth translatability assessment, resulted in wording modification of 25 items and deletion of 10 items. The majority of wording modifications were slight changes to enhance the clarity of the items. For example, one item "During the last two weeks, I was limited in preparing meals" was modified to "During the last two weeks, I was limited in preparing meals for my family."Additionally, several caregivers suggested including a new domain to capture their relationships with family members. In response to this feedback, a new domain, "Your Relationship with Your Family Members," was added. Items in this section used the same wording as the items in the "Your Relationship with Your Partner" section, with the word "partner" replaced by "family member(s)."The version of the PGCIQ created after content validity testing contains 49 items assessing 10 core domains: "Taking Care of Your Child," "Your Daily Activities," "Your Emotional Well-Being," "Your Household Expenses," "Your Physical Health," "Your Social Life," "Your Relationship with Your Partner," "Your Relationship with Your Family Members," "Your Employment Prior to Caring for Your Child with GERD," and "Your Current Employment." An additional, optional module with nine items, "Your Experiences Related to Diagnosis," is available for investigative research purposes and for use only at baseline.The following sections present considerations for the PGCIQ's use and potential limitations of the study. The following topics are addressed: "Your Relationship with Your Family Members"; symptom severity level; child's age and caregiver characteristics.The new domain, "Your Relationship with Your Family Members," was added following content validity testing interviews based on feedback from participants that additional questions about relationships with family members would provide valuable information. This new domain has not been tested with the wording "family members." As this is a significant change that has not been tested, this domain must be scrutinized during the linguistic validation and psychometric testing process.The PGCIQ was generated utilizing data from caregivers of children with a range of severity levels. Children with more severe GERD or significant co-morbidities  tended to increase the impact upon the primary caregiver across all nine domains. Conversely, a longer time period since diagnosis tended to reduce the impact on the caregiver. The reduction in impact over time appeared to be the result of two factors. First, many children eventually received successful treatment, which alleviated the GERD symptoms and reduced the strain on the caregiver. Second, the caregivers learned to accept and adapt to their children's condition with time.Given the age distribution of the study population, the PGCIQ is currently recommended for use in caregivers of pediatric GERD patients, newborn through three years old. Despite attempts to recruit across three age groups, ranging from newborn to 12 years of age, 80% of the focus group participants and 85% of the interview participants cared for a child aged newborn through three years of age. Although these age distributions were consistent with findings in the literature that approximately 70% of GERD cases spontaneously remit after age three, we felt that the majority of data favored infants and toddlers. Further testing of this instrument is therefore recommended in order to consider its use in populations of caregivers of children over the age of three. Researchers interested in extending the PGCIQ to children over the age of three are encouraged to consider the issues relevant to a child's age presented in the results section.The focus group discussion and content validity participants were primarily married women. From interviews with physicians, it was found that the majority of caregivers who seek treatment for pediatric GERD patients are women. Even though this instrument has been developed in a primarily female population, the identified caregiver issues appear to span gender roles. The men who participated in the focus group discussions were a small, but vocal minority, who elicited the same core domains as the female participants. Particular items of concern when using the questionnaire in men may be those related to domestic daily activities, given that these items tap more stereotypically female responsibilities. However, if the man is the primary caregiver, then it would stand to reason that he would be responsible for domestic daily activities. Future studies should seek to test the validity of the PGCIQ in larger populations of men and women to ensure that the items are equally relevant across gender roles.The PGCIQ has been developed in American English and American Spanish following a rigorous methodology of simultaneous item development for use in observational studies and multi-national clinical trials. The instrument is being linguistically validated from the American English version into several other languages following the appropriate methodology. After linguistic validation and psychometric testing is complete, a theoretical scoring model can be developed, and the PGCIQ may be used in international studies.Considering the age composition of the focus group and content validity interview population, the PGCIQ is currently recommended for use only in caregivers of pediatric GERD patients, newborn through three years old. Further testing of this instrument is recommended in order to consider its use in populations of caregivers of children over the age of three. Additionally, the study population was predominantly female, married and of moderate to high educational status. However, analysis of the caregivers' verbatim comments suggested that the nine domains were equally relevant to men and women, married and unmarried participants and caregivers of different educational levels. Future tests of the PGCIQ should include large samples of men and women of different marital and educational status to confirm the relevance of these domains.The PGCIQ is the first questionnaire to document the multi-dimensional impact of caring for an infant or young child with GERD, making it a valuable tool to gather information and quantify the relevant issues and impacts experienced by caregivers of pediatric GERD patients. Information gathered from this tool can be used to inform and educate physicians, managed health care organizations, pharmacists and other health care providers about the needs of caregivers. In addition, items in the PGCIQ were specifically developed to capture changes in caregiver impact in response to successful treatment. Because caregivers mentioned all nine domains as affected by their child's GERD, we conjecture that intervention effects would be associated with changed scores in all nine domains. Thus, the PGCIQ may provide valuable information in multi-national clinical evaluations regarding the value of different GERD treatments from the caregivers' perspective.This simultaneously generated patient-reported outcome instrument is one of the few examples of simultaneous development identified in the literature. This methodology results in a measure with a reduced risk of factors that might otherwise threaten the successful cross-cultural adaptation of the instrument, making the PGCIQ an appropriate instrument for adaptation into multiple languages.It is important for the PGCIQ to undergo psychometric testing to develop a final scoring model before the instrument can be used to assess the impact of pediatric GERD on caregivers. Academics and researchers interested in obtaining a copy of the PGCIQ should contact the lead author.JK Participated in the study design and coordinationDLK participated in the design, coordination and analysis and its interpretationSB participated in the field work and coordination and analysis and interpretationJAC conceived of the study and participated in its design


Virology 77:179–190, 2003). Here we evaluate the impact of these vaccines on oral transmission and evolution of SIV envelope variants.Oral infection of infant macaques with simian immunodeficiency virus (SIV) is a useful animal model to test interventions to reduce postnatal HIV transmission via breast-feeding. We previously demonstrated that immunization of infant rhesus macaques with either modified vaccinia virus Ankara (MVA) expressing SIV Gag, Pol and Env, or live-attenuated SIVmac1A11 resulted in lower viremia and longer survival compared to unimmunized controls after oral challenge with virulent SIVmac251 (Van Rompay env) region revealed two major env variants in the uncloned SIVmac251 inoculum. Plasma sampled from all infants 1 week after challenge contained heterogeneous SIV env populations including one or both of the most common env variants in the virus inoculum; no consistent differences in patterns of env variants were found between vaccinated and unvaccinated infants. However, SIV env variant populations diverged in most vaccinated monkeys 3 to 5 months after challenge, in association with the development of neutralizing antibodies.Limiting dilution analysis of SIV RNA followed by heteroduplex mobility assays of the V1–V2 envelope (These patterns of viral envelope diversity, immune responses and disease course in SIV-infected infant macaques are similar to observations in HIV-infected children, and underscore the relevance of this pediatric animal model. The results also support the concept that neonatal immunization with HIV vaccines might modulate disease progression in infants infected with HIV by breast-feeding. The continued need for breast-feeding in developing countries due to nutritional or socio-economic reasons poses a considerable risk for postnatal mother-to-child transmission of HIV, and breastfeeding is estimated to account for 33–50% of infant HIV infections worldwide -5. This Advances in the understanding of the mechanisms of oral transmission of HIV variants may aid the development of an effective infant HIV-1 vaccine. Recent studies have demonstrated that infants of HIV-infected women can be infected with single or multiple HIV variants ,7 shortlLongitudinal studies of HIV-infected adults have shown that the rate of disease progression is inversely related to the rate of evolution of HIV envelope quasispecies ,9. Also,env) region of SIV variants present in the SIVmac251 virus inoculum and compare the transmission and evolution of the SIV env quasispecies in plasma following oral inoculation of these vaccinated and unvaccinated infant macaques. Three major questions were addressed: (i) Compared to the SIVmac251 virus inoculum, are few SIV envelope variants transmitted orally?, (ii) Is the lower viremia and better clinical outcome of vaccinated infants related to the initial genetic diversity of SIV env quasispecies?, and, (iii) Is the evolution of SIV envelope quasispecies during the course of infection associated with the development of SIV neutralizing antibody? We demonstrate that while the vaccines did not modulate oral transmission of viral variants, an association was found between vaccine-induced enhanced antiviral immune responses, increased env diversity, and a slower disease course. These findings in vaccinated infant macaques are similar to observations in HIV-infected children with slow disease progression and support the relevance of the SIV infant macaque model for developing neonatal vaccine strategies to prevent pediatric HIV infection and AIDS.Simian immunodeficiency virus (SIV) infection of infant macaques is a useful and relevant animal model of pediatric HIV infection for rapidly testing the efficacy of pediatric HIV vaccine and drug interventions -20. Thisenv variants. To determine the most common variant(s) in the virus stock, six independent serial dilution experiments were conducted. Viral RNA was isolated from 1 ml of virus stock and 10-fold dilution series (undiluted to 10-9) of the RNA were prepared from 6 separate aliquots of virus stock. The resulting RNA was analyzed by RT-PCR and HMA. Figure -5 or 10-6 dilutions of viral RNA indicates that the undiluted SIVmac251-5/98 stock contains multiple env variants at high frequency. An RT-PCR endpoint (i.e. dilution to a single variant) was not reached in 3 of the 6 dilution experiments. An example of this is shown in dilution series A  that migrated to two different positions on the HMA gels. Based on these positions, the homoduplex bands that migrated furthest were referred to as VSEV-1 and the variants that migrated a shorter distance were designated VSEV-2  had 10- to 100-fold lower virus levels one week after SIVmac251 challenge than all but one infant (31378) infected with more heterogeneous populations of SIV variants  to VSEV-1 and VSEV-2, respectively (data not shown). The most common variants by end-point dilution in the 11 monkeys with transmission pattern A and A/C were similar to VSEV-1 , or VSEV-2  or both .env populations in plasma of the monkeys during the course of infection   Fig. . Resultsenv quasispecies in plasma varied among animals at the first sample  as indicated by the gel banding pattern  for all unvaccinated animals (Group 1) and for 7 of the 12 vaccinated animals  was observed by 3 to 5 months of infection in 4 of the 8 vaccinated monkeys  that were still relatively healthy at 28 weeks , we also observed little change or a decrease of genetic divergence  of plasma env quasispecies was evaluated by measuring levels of plasma antibodies that neutralized the homologous challenge virus, SIVmac251-5/98, during the course of infection  of initial infection were not potent enough to modulate the variant transmission patterns.Neither of the SIV vaccines used in this experiment (MVA-SIVgpe and SIVmac1A11), nor the presence of maternal antibodies in one of the MVA-SIVgpe immunized groups altered which envelope variants were transmitted because in each group, some monkeys became infected with more heterogeneous and others with more homogeneous virus populations. It is possible that neither MVA-SIVgpe nor SIVmac1A11 elicited immune responses that effectively targeted the predominant SIV env variants tended to be lower one week after oral inoculation with SIVmac251-5/98. The higher initial virus levels in infants infected with multiple variants may reflect higher replication capacities of diverse variant populations compared to those comprised of one main variant, especially in the initial target cells during the first days of infection. We have observed this previously for adult macaques inoculated intravaginally , where N is the number of partitions in a lane, and P(i) is the fraction of the total signal in partition i. The maximum possible entropy is ln(N), and we defined the normalized entropy as S/ln(N). The normalized entropy has a range of 0 to 1, where 0 reflects no diversity , and 1 reflects maximum entropy, in which the signal is evenly distributed throughout all partitions in the lane. Thus, entropy is large for lanes with many, closely spaced or overlapping bands and small for lanes with only one band or a few, narrow bands.The quasispecies diversity for each sample was estimated by calculating a normalized Shannon entropy, a measure of the breadth or spread of the signal distribution in each HMA gel lane, using the HDent program  for each HMA gel lane using the HDent program. The MMS is a measure of the midpoint of the total signal in an HMA gel lane that has values between 0 and 1, where 0 corresponds to the bottom of an HMA gel lane (i.e. nearest homoduplex bands) and 1 corresponds to the top of the lane. Thus, a MMS score of 1 reflects maximum sequence diversity ; a MMS value of 0 reflects maximum sequence similarity (> 98%) where all signal for a lane is in homoduplex bands and there are no visible heteroduplexes.Shannon entropy estimates quasispecies genetic diversity by measuring the pattern of SIV V1–V2  strands ,48,49. T® DNA mini kit, QIAgen, Valencia, CA) was used to screen for the presence of the rhesus macaque major histocompatibility complex (MHC) class I alleles Mamu A*01 and Mamu B*01, using a PCR-based technique [DNA extracted from lymphoid cells . For all statistical comparisons, a P value less than 0.05 was considered significant.Fisher's exact test, performed with Instat v. 2.03 , was used to evaluate possible association of SIV The author(s) declare they have no competing interests.JG carried out the HMA studies and drafted the manuscript; KVR participated in the design and coordination of the study, acquisition and analysis of data, and helped draft the manuscript; DM analyzed and interpreted all neutralizing antibody assays; PE and BM designed and provided the MVA constructs, participated in the experimental design and manuscript writing; MM designed and coordinated the study, assisted in the data analyses and helped draft the manuscript.


Although soy protein and its isoflavones have been reported to reduce the risk of osteoporosis in peri- and post-menopausal women, most of these studies are of short duration (i.e. six months). The objective of this study was to examine if one year consumption of soy-containing foods (providing 25 g protein and 60 mg isoflavones) exerts beneficial effects on bone in postmenopausal women.Eighty-seven eligible postmenopausal women were randomly assigned to consume soy or control foods daily for one year. Bone mineral density (BMD) and bone mineral content (BMC) of the whole body, lumbar (L1-L4), and total hip were measured using dual energy x-ray absorptiometry at baseline and after one year. Blood and urine markers of bone metabolism were also assessed.Sixty-two subjects completed the one-year long study. Whole body and lumbar BMD and BMC were significantly decreased in both the soy and control groups. However, there were no significant changes in total hip BMD and BMC irrespective of treatment. Both treatments positively affected markers of bone formation as indicated by increased serum bone-specific alkaline phosphatase (BSAP) activity, insulin-like growth factor-I (IGF-I), and osteocalcin . Neither of the protein supplements had any effect on urinary deoxypyridinoline excretion, a marker of bone resorption.Our findings suggest that although one year supplementation of 25 g protein per se positively modulated markers of bone formation, this amount of protein was unable to prevent lumbar and whole body bone loss in postmenopausal women. It is estimated by the year 2010, 35 million women in the United States either will have osteoporosis or be at risk of developing the disease if appropriate preventive measures are not taken -13. Soy Epidemiological data suggest that populations with high intakes of soy, i.e. Asians, have a lower incidence of osteoporotic fractures ,17. AsiaFrom the research point of view, there are a number of animal studies which have shown that soy protein and/or its isoflavones positively influence bone mineral density (BMD) ,20-26. IThe purpose of the present study was to examine the effects of one-year supplementation of soy-based products containing 25 g protein and 60 mg isoflavones on BMD, bone mineral content (BMC), serum and urinary markers of bone turnover in postmenopausal women. The rationale for choosing this amount of soy protein was based on the average intake of Asians ,19 and tPostmenopausal women younger than 65 years who were not on HRT or any prescription medications or herbal supplements, including soy isoflavones, known to positively influence bone were recruited. Women with cancer, liver disease, hypo- or hyperthyroidism, gastrointestinal disorders, insulin-dependent diabetes mellitus, pelvic inflammatory disease, and endometrial polyps were excluded from the study. The study protocol was approved by the Institutional Review Board at Oklahoma State University. Subjects signed a consent form after being provided with oral and written descriptions of the study. A complete medical history was obtained from all subjects before initiating the treatments. Subjects were also given routine physical and gynecological examinations. Subjects were independent living and were advised to maintain their usual physical activity.Eighty-seven eligible postmenopausal women were randomly assigned to one of two dietary treatments in a double-blind parallel study. The dietary treatments consisted of 25 g protein from soy products  or comparative control. The test foods were in the form of a snack bar, drink mix or cereal and were consumed daily for a period of one year. The soy products were soy protein-based and delivered 60 mg isoflavones per day whereas the control regimen was devoid of soy protein and isoflavones.To ensure double-blinding, the study participants were randomly assigned to one of the two treatments and the study supplies were provided to the study participants in unlabeled packages. Additionally, the identity of each treatment was revealed to the investigators and research personnel involved in the collection and analyses of the data only after all analyses were completed. For this study compliance was measured in two forms. First, study participants were provided with customized calendars for subjects to record how much of each of the cereal, the snack bar, or the drink mix they consumed, if any. Second, study participants were asked to return any unconsumed foods to the study site so they could be tallied. The study participants were advised by a registered dietitian to make appropriate adjustments in their daily food consumption to account for the additional energy and nutrients supplied by the treatment regimen.For each subject, medical and nutrition histories were obtained at the beginning of the study. One-week food frequency questionnaires were completed via interview by a registered dietitian at the beginning and at the end of the study. Nutrient analysis was performed using food analysis software . Anthropometric data were collected at the beginning, six months, and at the end of the study by a single trained staff member, as described elsewhere . Height Bone density was assessed at the beginning and at the end of treatment using dual energy x-ray absorptiometry  equipped with appropriate software for whole body BMD and BMC. Additionally, select regional sites, i.e. total hip and lumbar spine (L1-L4) were analyzed using high resolution software. The intra- and inter- assay coefficients of variations were 3.4% and 5.1% and 2.5% and 4.7% for BMC and BMD, respectively.Study participants were provided with routine physical and gynecological exams including a pap smear at baseline and at the end of the study. A venous blood sample was obtained after an overnight fast from each subject at the beginning, six months, and at the end of the study for various analyses. Blood samples were centrifuged at 2500 × g for 15 min at 4°C, serum samples were separated and stored at -20°C until analyses. Each study participant collected a 24-h urine specimen, excluding the first void, at the beginning, after six months, and at the end of the study. Urine volume was recorded and aliquots were stored at -20°C for later analyses.2), estrone (E1), estrone sulfate, follicle stimulating hormone (FSH), and sex hormone-binding globulin (SHBG) were assessed as we have previously described [To assess whether soy isoflavones modulate sex steroids and their availability, serum levels of 17β-estradiol  using a Cobas Fara II clinical analyzer. Urinary deoxypyridinoline (Dpd), a specific marker of bone resorption , was meaP < 0.05 was regarded as significant.Data were analyzed using analysis of variance methods with PROC MIXED in PC SAS  analyzing the main and interaction effects of the two factors, treatment (soy protein or control) and time (baseline or after treatment), using the SLICE option. Since each subject was measured at baseline and after treatment, a split plot (repeated measures) model was utilized. The mean changes in endpoints for the soy protein and control treatment groups were compared by analyzing interaction effects of the two factors, treatment and time, using the SLICE option. Data are reported as least square mean ± standard error (SE); unless otherwise indicated, Sixty-two of the 87 women completed the one year study resulting in an attrition rate of approximately 29%. Reasons for dropping from the study included medical conditions preventing continuation in the study (2 women in the soy group and 1 in the control group), starting HRT (1 woman in the soy group and 3 in the control group), noncompliance (2 women in the soy group), dislike of the volume or flavor of the food (3 women in the control group), gastrointestinal side effects (2 women in the control group), food was causing headaches (1 woman in the control group), and personal reasons (3 women in the soy group and 2 in the control group). Five additional women in the soy group decided to discontinue the study without citing a particular reason.Women in both treatment groups had similar baseline characteristics Table . Body wedata not shown).Subjects in both the soy and control groups lost whole body and lumbar BMD and BMC after one year, but no change was observed in the total hip Table . Whole bBoth dietary protein supplements significantly increased serum markers of bone formation, i.e. osteocalcin, BSAP, IGF-I and ALP Table . However2, E1, and estrone sulfate. None of the treatment significantly influenced these sex hormones  isoflavones independent of soy protein can prevent ovarian hormone deficiency-associated bone loss; 2) consumption of soy containing food or intake of isoflavones on a daily basis is necessary to observe the expected beneficial effects on bone or simply intermittent use will produce the same results; 3) the effect of soy protein or its isoflavones on bone is transitory; and 4) the combination of soy isoflavones and lower doses of antiresorptive agents can prevent postmenopausal bone mineral loss. As these and other questions are answered, the efficacy of soy protein and its isoflavones as alternative and/or adjunctive treatments for postmenopausal osteoporosis can be determined.The author(s) declare that they have no competing interests.


Published October 19, 2004PLoS Medicine, volume 1, issue 1:In Nevirapine and Efavirenz Elicit Different Changes in Lipid Profiles in Antiretroviral-Therapy-Naive Patients Infected with HIV-1Frank van Leth, Prahpan Phanuphak, Erik Stroes, Brian Gazzard, Pedro Cahn, et al.DOI: 10.1371/journal.pmed.0010019The following information was missing from the legend for There was also a line with open circles in