Boltzmann's equation at 150: Traditional and modern solution techniques for charged particles in neutral gases

Seminal gas discharge experiments of the late 19th and early 20th centuries laid the foundations of modern physics, and the influence of this "golden era" continues to resonate well into the 21st century through modern technologies, medical applications, and fundamental scientific investigations. Key to this continuing success story has been the kinetic equation formulated by Ludwig Boltzmann in 1872, which provides the theoretical foundations necessary for analyzing such highly non-equilibrium situations. However, as discussed here, the full potential of Boltzmann's equation has been realized only in the past 50 years or so, with modern computing power and analytical techniques facilitating accurate solutions for various types of charged particles (ions, electrons, positrons, and muons) in gases. Our example of thermalization of electrons in xenon gas highlights the need for such accurate methods-the traditional Lorentz approximation is shown to be hopelessly inadequate. We then discuss the emerging role of Boltzmann's equation in determining cross sections by inverting measured swarm experiment transport coefficient data using machine learning with artificial neural networks.

Practice variation in the diagnosis of acute rejection among pediatric heart transplant centers: An analysis of the pediatric heart transplant society (PHTS) registry

BACKGROUND

Freedom from rejection in pediatric heart transplant recipients is highly variable across centers. This study aimed to assess the center variation in methods used to diagnose rejection in the first-year post-transplant and determine the impact of this variation on patient outcomes.

METHODS

The PHTS registry was queried for all rejection episodes in the first-year post-transplant (2010-2019). The primary method for rejection diagnosis was determined for each event as surveillance biopsy, echo diagnosis, or clinical. The percentage of first-year rejection events diagnosed by surveillance biopsy was used to approximate the surveillance strategy across centers. Methods of rejection diagnosis were described and patient outcomes were assessed based on surveillance biopsy utilization among centers.

RESULTS

A total of 3985 patients from 56 centers were included. Of this group, 873 (22%) developed rejection within the first-year post-transplant. Surveillance biopsy was the most common method of rejection diagnosis (71.7%), but practices were highly variable across centers. The majority (73.6%) of first rejection events occurred within 3-months of transplantation. Diagnosis modality in the first-year was not independently associated with freedom from rejection, freedom from rejection with hemodynamic compromise, or overall graft survival.

CONCLUSIONS

Rejection in the first-year after pediatric heart transplant occurs in 22% of patients and most commonly in the first 3 months post-transplant. Significant variation exists across centers in the methods used to diagnose rejection in pediatric heart transplant recipients, however, these variable strategies are not independently associated with freedom from rejection, rejection with hemodynamic compromise, or overall graft survival.

Reduced model of plasma evolution in hydrogen discharge capillary plasmas

A model describing the evolution of the average plasma temperature inside a discharge capillary device including Ohmic heating, heat loss to the capillary wall, and ionization and recombination effects is developed. Key to this approach is an analytic quasistatic description of the radial temperature variation which, under local thermal equilibrium conditions, allows the radial behavior of both the plasma temperature and the electron density to be specified directly from the average temperature evolution. In this way, the standard set of coupled partial differential equations for magnetohydrodynamic (MHD) simulations is replaced by a single ordinary differential equation, with a corresponding gain in simplicity and computational efficiency. The on-axis plasma temperature and electron density calculations are benchmarked against existing one-dimensional MHD simulations for hydrogen plasmas under a range of discharge conditions and initial gas pressures, and good agreement is demonstrated. The success of this simple model indicates that it can serve as a quick and easy tool for evaluating the plasma conditions in discharge capillary devices, particularly for computationally expensive applications such as simulating long-term plasma evolution, performing detailed input parameter scans, or for optimization using machine-learning techniques.

Combining laser interferometry and plasma spectroscopy for spatially resolved high-sensitivity plasma density measurements in discharge capillaries

Precise characterization and tailoring of the spatial and temporal evolution of plasma density within plasma sources are critical for realizing high-quality accelerated beams in plasma wakefield accelerators. The simultaneous use of two independent diagnostics allowed the temporally and spatially resolved detection of plasma density with unprecedented sensitivity and enabled the characterization of the plasma temperature in discharge capillaries for times later than 0.5 µs after the initiation of the discharge, at which point the plasma is at local thermodynamic equilibrium. A common-path two-color laser interferometer for obtaining the average plasma density with a sensitivity of 2 × 10¹⁵ cm^-2 was developed together with a plasma emission spectrometer for analyzing spectral line broadening profiles with a resolution of 5 × 10¹⁵ cm^-3. Both diagnostics show good agreement when applying the spectral line broadening analysis methodology of Gigosos and Cardeñoso in the temperature range of 0.5 eV-5.0 eV. For plasma with densities of 0.5-2.5 × 10¹⁷ cm^-3, temperatures of 1 eV-7 eV were indirectly measured by combining the diagnostic information. Measured longitudinally resolved plasma density profiles exhibit a clear temporal evolution from an initial flat-top to a Gaussian-like shape in the first microseconds as material is ejected out from the capillary. These measurements pave the way for highly detailed parameter tuning in plasma sources for particle accelerators and beam optics.

Electron scattering and transport in liquid argon

The transport of excess electrons in liquid argon driven out of equilibrium by an applied electric field is revisited using a multi-term solution of Boltzmann's equation together with ab initio liquid phase cross-sections calculated using the Dirac-Fock scattering equations. The calculation of liquid phase cross-sections extends previous treatments to consider multipole polarisabilities and a non-local treatment of exchange, while the accuracy of the electron-argon potential is validated through comparison of the calculated gas phase cross-sections with experiment. The results presented highlight the inadequacy of local treatments of exchange that are commonly used in liquid and cluster phase cross-section calculations. The multi-term Boltzmann equation framework accounting for coherent scattering enables the inclusion of the full anisotropy in the differential cross-section arising from the interaction and the structure factor, without an a priori assumption of quasi-isotropy in the velocity distribution function. The model, which contains no free parameters and accounts for both coherent scattering and liquid phase screening effects, was found to reproduce well the experimental drift velocities and characteristic energies.

Monte Carlo study of coherent scattering effects of low-energy charged particle transport in Percus-Yevick liquids

We generalize a simple Monte Carlo (MC) model for dilute gases to consider the transport behavior of positrons and electrons in Percus-Yevick model liquids under highly nonequilibrium conditions, accounting rigorously for coherent scattering processes. The procedure extends an existing technique [Wojcik and Tachiya, Chem. Phys. Lett. 363, 381 (2002)], using the static structure factor to account for the altered anisotropy of coherent scattering in structured material. We identify the effects of the approximation used in the original method, and we develop a modified method that does not require that approximation. We also present an enhanced MC technique that has been designed to improve the accuracy and flexibility of simulations in spatially varying electric fields. All of the results are found to be in excellent agreement with an independent multiterm Boltzmann equation solution, providing benchmarks for future transport models in liquids and structured systems.

Anticoagulation and incidence of late cerebrovascular accidents following the Fontan procedure

Thromboembolic events are a well-reported complication following the Fontan procedure, but no previous studies have compared the incidence of thromboembolic events relative to the prophylactic anticoagulation strategy utilized. We examined the time-adjusted incidence of late thromboembolic events relative to chronic anticoagulation strategy. All patients who have undergone Fontan palliation and are followed at our institution were reviewed. All thromboembolic and major bleeding events were recorded and compared among different subgroups (anticoagulant medication utilized, Fontan variant, and the presence of a residual right-to-left shunt). The incidence of late cerebrovascular accidents (CVAs) per patient-year was calculated for each subgroup. The records of 132 patients were analyzed (median follow-up, 7.6 years; 1066.5 total patient-years). There were no major bleeding complications. One patient receiving no anticoagulation therapy developed a symptomatic thrombus 6 months after Fontan. Three patients suffered late CVAs (range, 3-7 years); 2 were receiving aspirin, and the other received no anticoagulation therapy. All 3 had lateral tunnel Fontan and a residual right-to-left shunt. The overall incidence of late CVA was 2.3%, with an event rate of 0.28% per patient-year. Late CVA was not related to anticoagulation strategy or time from Fontan procedure but was associated with a residual right-to-left shunt and lateral tunnel-type Fontan palliation (p < 0.001). Regardless of anticoagulation strategy utilized, symptomatic CVA is a rare long-term complication following the Fontan procedure.

The impact of pharmacogenomic factors on steroid dependency in pediatric heart transplant patients using logistic regression analysis

Many pharmacogenomic predictors of drug response are now available, and include both drug metabolism-disposition factors and drug targets. Information on statistical approaches to analyzing large clinical data sets in relation to genetic polymorphisms is limited. The objective of this study was to evaluate whether logistic regression could identify pharmacogenomic predictors of outcome in a large data set in a complex transplant patient population. Seventy pediatric heart transplant patients were studied. Patients were followed for at least 1 yr post-transplantation as outpatients, and weaned from corticosteroids if clinically appropriate. Logistic regression analysis was used to identify the predictors of steroid dependency. The dependent variable was the presence or absence of steroid therapy at 1 yr post-transplantation. The independent variables were the patients' transplant age, gender, MDR1 C3435T and G2677T, CYP3A53B and cytokine polymorphisms. By chi-square test for the MDR1 C3435T polymorphism, 12 of 18 (67%) patients in the CC group were still on prednisone, whereas only 18 of 47 (38%) of the CT/TT group were still receiving prednisone (p = 0.04). For the IL-10 groups, two of 15 patients with the high producer genotype (13.3%) remained on prednisone, in comparison with 16 of 28 patients with the intermediate producer genotype (57.1%) and 15 of 26 patients with the low producer genotype (57.7%, p = 0.01). Logistic regression analysis confirmed MDR1 C3435T (p = 0.021), and IL-10 polymorphisms (intermediate producer genotype p = 0.015; low producer genotype p = 0.013) as independent risk factors for steroid dependency at 1 yr after transplantation. This approach identifies pharmacogenomic factors, which can be studied more extensively in larger data sets, and used in prospective studies to individualize immunosuppressive therapy following solid organ transplantation.

Affective and evaluative descriptors of pain in the McGill Pain Questionnaire: Reduction and reorganization

Recent reports indicate that several descriptors of pain sensations in the McGill Pain Questionnaire (MPQ) are difficult to classify within MPQ sensory subcategories because of incomprehension, underuse, or ambiguity of usage. Adopting the same methodology of recent studies, the present investigation focused on the affective and evaluative subcategories of the MPQ. A decision rule revealed that only 6 of 18 words met criteria for the affective category and 5 of 11 words met criteria for the evaluative category, thus warranting a reduced list of words in these categories. This reduction, however, led to negligible loss of information transmitted. Despite notable changes in classification, the intensity ratings of the retained words correlated very highly with those originally reported for the MPQ. In conclusion, although the intensity ratings of MPQ affective and evaluative descriptors need no revision, selective reduction and reorganization of these descriptors can enhance the efficiency of this approach to pain assessment.

Adverse sexual and psychological effects of male infant circumcision

A survey of the 35 female and 42 gay sexual partners of circumcised and genitally intact men, and a separate survey of 53 circumcised and 30 genitally intact men themselves, indicated that circumcised men experienced significantly reduced sexual sensation along with associated long-lasting negative emotional consequences.

Hematologic abnormalities in children and young adults receiving tacrolimus-based immunosuppression following cardiothoracic transplantation

To define the incidence, course, and etiology of hematologic abnormalities in children on tacrolimus-based immunosuppression, we reviewed records of 106 transplant patients (70 heart, 16 heart and lung, 20 double lung), 0-21 yr of age, who were transplanted at the Children's Hospital of Pittsburgh from 1989 to 1997. Fifty-four of the 106 patients (51%) developed 65 abnormal hematologic episodes (32 anemia, nine neutropenia, nine thrombocytopenia, 15 simultaneous anemia and neutropenia with or without thrombocytopenia). Common etiologies included: infections, post-transplant lymphoproliferative disease, and medications. Eleven episodes (seven anemia, one neutropenia, and three simultaneous anemia and neutropenia) had unclear etiologies and process of elimination suggested an association with tacrolimus. Interventions included filgrastim (effective in 15 of 15 patients, with resolution of neutropenia in a median of 5 days) and epoetin alfa (effective in five of 16 patients, including four of four patients with anemia possibly related to tacrolimus). Five patients (two with neutropenia and three with simultaneous neutropenia and anemia) were switched to cyclosporin A (CsA); rapid resolution occurred in four of the five patients, suggesting a possible association of the hematologic abnormalities with tacrolimus. In summary, hematologic abnormalities are common in children on tacrolimus-based immunosuppression. Most of these hematologic abnormalities are caused by common etiologies; however, a sub-population exists where tacrolimus may be the etiologic agent. Anemia and neutropenia respond to treatment with epoetin alfa and filgrastim. After thorough investigation, a trial switch to CsA may be warranted.

Analysis of TCR Vbeta repertoire and cytokine gene expression in patients with idiopathic dilated cardiomyopathy

Although the etiopathogenesis of idiopathic dilated cardiomyopathy (IDC) is still unclear, it is widely accepted that a complex interplay between viral infections and immune mechanisms is the basis of disease genesis. Previously, we showed that heart-infiltrating T cells of patients suffering from acute, fulminant Coxsackie virus B3+-IDC shared a preferential usage of three variable gene segments of the T cell receptor beta chain-(TCR-Vbeta) encoding families Vbeta3, 7 and 13.1. This indicated the possible presence of a superantigen-driven immune response. Here, we further investigated the IDC immunological scenario by analysing different phenotypes of heart-infiltrating cells: TCR repertoires, cytokine expression and presence of enterovirus-specific antigens. IDC patients who underwent heart transplantation at different times after the onset of heart failure were studied. A cardiac infiltrate of CD4+ and CD8+ T cells was present together with activated macrophages. Furthermore, the same Vbeta gene families, previously found to be skewed in hearts from fulminant cases of CVB3+-IDC, together with two additional Vbeta gene families, Vbeta1 and 5B, were increased. IL-1beta, IL-2, IL-6 and IFN-gamma were expressed in the myocardium while others, like IL-4 were not. In conclusion, an orchestrated complex of immune mechanisms seems to be the basis of IDC etiopathogenesis.

A preliminary study of hormone replacement therapy and psychological mood states in perimenopausal women

Hormone replacement therapy (HRT) for perimenopausal women has been suggested to minimize the physical symptoms of menopause and improve mood and psychological functioning; however, the therapy remains controversial. In this study the effects of such therapy (comprising tablets, patches, and implants) on mood states was investigated within a sample of 70 perimenopausal women who were attending a family planning clinic within the Brisbane metropolitan area. On a battery of standardized questionnaires, including the General Health Questionnaire, the Profile of Mood States, the Eysenck Personality Questionnaire, and the Menstrual Distress Questionnaire, those 35 women who were using hormone replacement therapy prescribed by the clinic physician reported significantly lower scores on anxiety, insomnia, and somatic symptoms than did a comparable group of 35 untreated perimenopausal women. These findings provide some tentative support for the beneficial effects of the therapy on physical symptoms and psychological mood states related to the onset of menopause. Given increased life expectancy, there is a growing need for research into issues of aging.

Posttransplant diabetes mellitus in pediatric thoracic organ recipients receiving tacrolimus-based immunosuppression

BACKGROUND

Posttransplantation diabetes mellitus (PTDM) is a well-known complication of tacrolimus-based immunosuppression in both adult and pediatric solid organ recipients. The "natural history" of diabetes in the pediatric thoracic transplant population has not yet been described.

METHODS

We identified all pediatric thoracic transplant patients receiving tacrolimus-based immunosuppression who developed PTDM. Medical records were reviewed, with a particular focus on the clinical course of PTDM and its relationship to drug weaning.

RESULTS

Diabetes developed in 24 of 143 (17%) 30-day survivors of heart (12/96, 13%) and heart-lung/lung (12/ 47, 26%) transplantation. In 17 (71%) patients, the immunosuppressive regimen at the onset of PTDM also included maintenance corticosteroids. Seventeen patients demonstrated glucose intolerance before the onset of diabetes. Nine patients (38%) developed diabetes during pulsed corticosteroid therapy. Median time of onset after transplantation was 9.0 months. All patients required s.c. insulin for glucose control. The median follow-up from transplant was 49.9 months. There was a significant decrease in mean tacrolimus dosage (P<0.01), tacrolimus level (P<0.04), and steroid dosage (P<0.02) from onset of PTDM to most recent follow-up. Despite this significant reduction in immunosuppression, only 3/24 (13%) patients were successfully weaned off insulin.

CONCLUSIONS

Diabetes mellitus is a common complication in pediatric thoracic transplant patients receiving tacrolimus-based immunosuppression. Insulin dependence in our population rarely resolved, even after lowering tacrolimus and steroid doses. Discontinuation of steroids did not guarantee resolution of diabetes.

Endomyocardial biopsy in pediatric heart transplant recipients: a useful exercise? (Analysis of 1,169 biopsies)

The objective of this study was to define the diagnostic yield for endomyocardial biopsy (EMB) procedures performed for various indications in a large pediatric heart transplant population. Endomyocardial biopsy procedure has been employed as the 'gold standard' for rejection surveillance. Previous studies have questioned the value of surveillance EMB beyond the early post-transplant period. We retrospectively reviewed data on 82 pediatric heart transplant recipients with serial EMB. A total of 1,169 EMB were performed during a follow-up period of 2-149 months (median 41 months). EMB were classified by age at transplantation, time from transplant, immunosuppressive regimen used [tacrolimus vs. cyclosporin A (CsA)] and indication, i.e. surveillance, follow-up after rejection or lowering of immunosuppression, non-specific clinical symptoms and graft dysfunction. During the first year after heart transplantation, surveillance EMB demonstrated significant rejection [International Society for Heart and Lung Transplantation (ISHLT) grade > or = 3A] in 18% of biopsies with the yield being 14-43% for all other indications. Surveillance EMB 1-5 yr post-transplantation were found to have a lower diagnostic yield in infants (4%, vs. 13% in children) and in patients with favorable first-year rejection history (9% vs. 17% in 'frequent rejectors'). Tacrolimus-based immunosuppression was associated with significantly less rejection, but only in the first year post-transplantation (14% in tacrolimus vs. 24% in CsA surveillance EMB, p = 0.035). Surveillance EMB remains an important diagnostic tool for rejection surveillance during the first 5 years after pediatric heart transplantation. Endomyocardial biopsy is particularly warranted after reduction of immunosuppression and for monitoring for ongoing rejection after treatment of acute rejection episodes.

Discriminant validity of the illness behavior questionnaire and Millon Clinical Multiaxial Inventory-III in a heterogeneous sample of psychiatric outpatients

The discriminant validity of measures of abnormal illness behaviors and psychopathology was examined in three samples differing in illness proneness: a sample of young healthy university students (n = 38), a general community sample (n = 36), and a sample of clinical psychiatric outpatients (n = 36). Adjustment to illness was measured using the Illness Behaviour Questionnaire (IBQ; Pilowsky & Spence, 1994), while the Millon Clinical Multiaxial Inventory-III (MCMI-III; Millon, 1994) was used to measure clinical syndromes and personality. MANCOVAs were performed across the three groups on the IBQ and the MCMI-III categories, separately. As expected, clinical outpatients obtained significantly higher scores than did nonclinical groups on most of the IBQ scales, suggesting discernible discriminant validity. However, the lack of discrimination between groups on several of the MCMI-III scales raises questions about the test validity of this multidimensional instrument.

Interaction of psychosocial and physical risk factors in the causation of mammary cancer, and its prevention through psychological methods of treatment

Some 8059 healthy women (mean age 58 years) were studied in 1973 with the aim of establishing the presence or absence of a variety of physical and psychological risk factors for mammary cancer. Mortality was established in 1988. factor predictors were highly significant. Physical risk factors were more predictive than psychological ones, but both interacted synergistically to predict mortality. Alone, psychological (stress) factors had little effect, while-physical factors did. However, psychological factors seemed to potentiate the effect of physical factors, particularly in the middle range. The causal relevance of psychological factors was established in a special intervention study using autonomy training as a method of prophylactic therapy and comparing outcome with the effects of no therapy (control).

Optimal dosing of intravenous tacrolimus following pediatric heart transplantation

BACKGROUND

Early experience with intravenous tacrolimus at high doses (0.1-0.15 mg/kg/day) was associated with frequent clinical toxicity. The optimal dosing regimen after pediatric heart transplantation is unknown.

METHODS

We retrospectively reviewed data on the last 45 pediatric heart transplant recipients to document the time required to achieve therapeutic blood levels and the safety of 2 differing intravenous dosing regimens (tacrolimus 0.03 & 0.05 mg/kg/day as continuous i.v. infusion). Target plasma levels were (1.2-1.7 ng/ml) with levels >2.0 ng/ ml considered toxic, and target whole blood levels were 15-20 ng/ml with levels >25 ng/ml considered toxic.

RESULTS

Mean age at transplantation was 7.5 +/- 5.6 years (0.1-18), and 14 were infants. Intravenous tacrolimus was commenced at a mean of 7 +/- 3 hours (range 2-16) after arrival in the ICU. Eight patients were excluded from analysis because of protocol modifications. Of the remaining 37 pts, 9 received initial infusion at 0.03 mg/kg/day; 3 (33%) achieved 'therapeutic' levels within 48 hours and 1 patient had a toxic level (27 ng/ml) at 36 hours. Twenty-eight patients received 0.05 mg/kg/day; 18 (64%) achieved therapeutic levels within 48 hours and 9 (32%) developed toxic levels. Patients with toxic whole blood levels had higher tacrolimus levels on first blood assay compared to those who did not develop toxicity (16.4 +/- 3.4 vs 9.3 +/- 3.9, p < .0001; level >10 ng/ml on first assay in 7/7 toxic patients vs 7/19 without toxicity, p = .004). Patients receiving the higher dose regimen had fewer episodes of moderate or severe rejection (> or =Grade 3A) at first biopsy than those receiving the lower dose infusion (32% vs 75%; p = .046). No patient required renal dialysis.

CONCLUSIONS

Dosing below 0.05 mg/kg/day may result in clinically important delay in achieving therapeutic levels. Toxicity may be reduced by frequent monitoring of levels for the first 48 hours after transplantation especially when the initial level is >10 ng/ml.

Idiopathic dilated cardiomyopathy: a superantigen-driven autoimmune disease

BACKGROUND

Many cases of idiopathic dilated cardiomyopathy (IDC) result from an inflammatory myocarditis. The specific immunological mechanisms are not yet defined. Various autoimmune diseases are associated with superantigen-triggered immune responses, resulting in massive T-cell activation and tissue damage. We studied 3 cases in a search for evidence that such a phenomenon is also implicated in IDC.

METHODS AND RESULTS

Myocardial, lymph node, and thymic tissue samples were obtained from IDC patients who were undergoing heart transplantation. Infiltrating immune-cell phenotypes and gene expression of T-cell receptor (TCR) alpha- and beta-chain variable (Valpha and Vbeta) regions were analyzed by immunostaining and polymerase chain reaction. Similar technical approaches were used to assay the tissues for the presence of coxsackievirus B (CVB). In all the specimens analyzed, an overexpression of the TCR Vbeta3, Vbeta7, and Vbeta13.1 gene families was detected among the infiltrating T cells. These tissues were also found to be CVB3-positive. In vitro exposure of peripheral blood mononuclear cells to lysates of cells infected with CVB3 was capable of stimulating expansion of the same TCR Vbeta families. The TCR Valpha repertoire was never found to be skewed.

CONCLUSIONS

A superantigen-mediated immune response is involved in human heart disease. CVB3 may directly or indirectly trigger this response, suggesting a possible mechanistic link between CVB infection and myocarditis development progressing to IDC.

Clinical relevance of in vitro propagation of activated lymphocytes from endomyocardial biopsy samples of pediatric heart transplant recipients

In vivo activated T-lymphocytes can be cultured from endomyocardial biopsy samples of human cardiac allografts, sometimes even in the absence of histological rejection. We investigated the clinical relevance of this "lymphocyte growth assay" in pediatric heart transplant recipients. Specifically, we wished to determine if: (i) positive lymphocyte growth from EMB samples in the absence of significant rejection identifies a patient as being at increased risk for the development of acute rejection; (ii) withdrawal or major dose reduction of corticosteroids in the presence of lymphocyte growth results in high risk of rebound rejection; and (iii) presence of lymphocyte growth during acute rejection helps predict the response to treatment. Cultures were performed on 789 consecutive EMB samples from 65 pediatric heart transplant recipients in media containing 30 U/ml of recombinant IL-2. T-lymphocytes were cultured from 16% of EMB samples with low grade rejection (grade 0-1b) and from 34% of EMB samples with grade 2-4 rejection. EMB samples obtained early post-transplant (<180 days) were significantly more likely to yield positive lymphocyte growth compared to biopsies obtained late for any given rejection grade. Lymphocyte growth was comparable between patients managed with cyclosporine or tacrolimus based immunosuppression. For 227 EMB samples without rejection, a subsequent EMB sample was obtained within 12 weeks. Lymphocyte cultures were positive in 47 of these 227 EMB samples (21%), and in 19 out of 47 (40%) cases acute rejection (grade 2-4) was present on the follow-up EMB sample. By contrast, of 180 biopsies without growth, only 29 (16%) showed rejection at the next EMB (p<0.0001). When a follow-up biopsy was performed within 12 weeks of corticosteroid withdrawal, "rebound rejection" was observed in 3 out of 10 (30%) cases where the previous EMB sample yielded positive lymphocyte growth and in 4 out of 38 (11%) cases when it did not (p=0.29). The presence of lymphocyte growth in association with rejection was also predictive of whether rejection would resolve following high dose intravenous corticosteroid therapy (persistent rejection in 33 out of 50 (66%) cases with positive growth, versus 25 out of 80 (31%) cases without growth (p<0.0001)). Thus, positive lymphocyte growth is strongly associated with higher grade of rejection and earlier time from transplantation. Lymphocyte growth in the absence of rejection indicates high risk for rejection within the next 12 weeks. Growth in association with acute rejection indicates high probability of persistence of rejection following treatment with high dose corticosteroids.

Six-month prevalence of phobic symptoms in Iceland: an epidemiological postal survey

An epidemiological questionnaire survey of the prevalence of the various types of phobias was undertaken among the Icelandic population. Out of 1,000 individuals surveyed, in accord with national census data held in Reykjavík, 775 questionnaires were returned. Results confirmed that among Icelanders, phobic symptoms overall are more prevalent among women than men. Prevalence rates were lower for individuals 45 years or older, suggesting that extinction may occur with ageing. Divorced or separated individuals were most at risk, as were women homemakers, disabled, or unemployed persons. Education was inversely related to the incidence of all types of phobias, with individuals with less than 10 years of education reporting the highest rates of phobia. Most respondents attributed the onset of their phobias to a specific terrifying experience, and in many cases, to observing another person displaying an intense fear reaction in a given situation. Factor analysis of the data indicated that social anxiety phobias accounted for the greatest proportion of variance.

Posttransplantation lymphoproliferative disorders in pediatric thoracic organ recipients

OBJECTIVE

To determine the frequency, predisposing factors, clinical presentation, and outcome of posttransplantation lymphoproliferative disorders (PTLDs) in pediatric thoracic organ transplant recipients.

METHODS

Retrospective review of the medical records of all 120 children who survived longer than 1 month after thoracic organ transplantation at our center.

RESULTS

PTLD was diagnosed in 14 patients (11.7%), including 7.7% of heart and 19.5% of heart-lung/lung recipients. Presentation of PTLD was variable, ranging from asymptomatic lung nodules on chest radiograph to diffuse multiorgan failure. Treatment with a reduction of immunosuppression and antiviral therapy resulted in resolution of PTLD in eight patients. Eight patients died. PTLD contributed to death in five. No patient seropositive for Epstein-Barr virus (EBV) before transplantation had PTLD. There was a significant association between primary EBV infection after transplantation and the presence of PTLD.

CONCLUSIONS

PTLD occurs with greater frequency in pediatric thoracic organ transplant recipients than in the adult transplant population. Primary EBV infection after transplantation is the major risk factor for the development of PTLD. Patients in whom primary EBV infection develops after transplantation should be managed with a reduction in immunosuppression and with heightened surveillance for the development of PTLD.

Long-term survivors of pediatric heart transplantation: a multicenter report of sixty-eight children who have survived longer than five years

OBJECTIVE

Short-term survival after pediatric heart transplantation is now excellent, but ultimately the efficacy of this procedure will depend on duration and quality of survival. We sought to evaluate the clinical course of long-term survivors of heart transplantation in childhood.

METHODS

Patients who had undergone heart transplantation at the university hospitals of Stanford, Columbia, and Pittsburgh between 1975 and 1989 and survived longer than 5 years from transplantation were identified and their clinical courses retrospectively reviewed.

RESULTS

Sixty eight children have survived more than 5 years from transplantation, and 60 (88%) are currently alive with a median follow-up of 6.8 years (5 to 17.9 years). Thirteen have survived more than 10 years from transplantation. Renal dysfunction caused by immunosuppressive agents was common, and two patients required late renal transplantation. Lymphoproliferative disease or other neoplasm occurred in 12 patients, but none resulted in death. Coronary artery disease was diagnosed in 13 patients (19%), leading to retransplantation in eight. Death after 5 years was related to acute or chronic rejection in 5 of 8 cases. Two of the deaths were directly related to noncompliance with immunosuppressive medication. All survivors are in New York Heart Association class 1.

CONCLUSIONS

Long-term survival with good quality of life can be achieved after heart transplantation in childhood, though complications of immunosuppression remain common. Posttransplantation coronary artery disease is emerging as the main factor limiting long term graft and patient survival.

Effects of menstrual cycle moods and symptoms on academic performance: a study of senior secondary school students

BACKGROUND

Menstrual cycle moods and symptoms may well play a discernible role in the academic performance of some post-pubescent adolescent female students.

AIMS

It was expected that menstrually related moods and symptoms would have both negative and positive influences on academic learning outcomes, and that the magnitude of these effects would be directly proportional to the salience of such moods and symptoms across the monthly cycle.

SAMPLES

The sample comprised 427 post-pubescent female students (Years 10, 11, and 12) attending a number of senior secondary schools within the Melbourne metropolitan area, Australia.

METHODS

Given the sensitivity of conducting such a study, combined with the logistical difficulties of obtaining prospective data within school settings, retrospective Menstrual Distress Questionnaire (MDQ) scores were related to the previous end-of-year academic grades across a wide range of 18 senior school subjects. Despite the conservative design constraints and associated data analyses (correlations were not corrected for attenuation), some systematic effects were observed.

RESULTS

At the premenstrual, menstrual, and intermenstrual phases, moods and symptoms significantly predicted grades in 14 per cent, 7 per cent, and 13 per cent of instances, respectively. Although most significant relationships were negative, scores on the MDQ Arousal scale for the intermenstrual phase positively predicted grades in English Literature, (general) Mathematics, Art and Craft, History, Mathematics 1, and Study of Society.

CONCLUSIONS

Evidently, menstrual cycle variables play a small, but discernible role on academic learning outcomes, contributing both positively and negatively to performance. Future, prospective studies are now needed to provide a more definitive account of menstrual cycle influences on academic performance.

New-onset diabetes mellitus in pediatric thoracic organ recipients receiving tacrolimus-based immunosuppression

BACKGROUND

Tacrolimus has a negative effect on the pancreatic beta islet cell, and both glucose intolerance and diabetes mellitus are well-recognized complications of tacrolimus-based immunosuppression among adult solid organ transplant recipients.

METHODS

To determine the association between tacrolimus and new-onset diabetes mellitus in childhood, we reviewed data on 78 pediatric heart and heart-lung/lung recipients receiving tacrolimus-based immunosuppression. Trough tacrolimus levels, fasting and random blood glucose levels, and corticosteroid requirements were reviewed. Diabetes was defined as glucose intolerance requiring long-term insulin treatment more than 30 days after transplantation.

RESULTS

No patient had diabetes before introduction of tacrolimus. In heart-lung/lung recipients, 12 of 28 (43%) had development of diabetes at a median follow-up of 7 months (range 1 to 39). In this group diabetes developed in three of eight (38%) patients with cystic fibrosis and nine of 20 (45%) without (p = NS). In contrast, only two of 50 (4%) heart transplant recipients had development of diabetes. Of the 14 patients with diabetes, 10 had development of diabetes during augmentation of immunosuppression with pulsed corticosteroids. Tacrolimus trough levels were significantly lower in heart compared with heart-lung/lung transplant recipients (9.4 +/- 3.3 versus 15.3 +/- 0.9 ng/ml) (p < 0.01), and at latest follow-up significantly fewer heart transplant recipients were treated with maintenance corticosteroids (28% versus 75%; p < 0.01). In the heart-lung/lung group, no significant difference in tacrolimus levels was found between patients with and without diabetes, nor was there a significant difference in the average corticosteroid dose or number of pulses of corticosteroids per patient.

CONCLUSIONS

New-onset diabetes mellitus is rare in pediatric heart transplant recipients receiving tacrolimus-based immunosuppression, but it occurs with a high incidence after pediatric heart-lung/lung transplantation and usually develops during pulsed corticosteroid therapy. However, it is currently not possible to predict which heart-lung/ lung transplant recipients will have development of this serious complication.

Are chest radiographs and electrocardiograms still valuable in evaluating new pediatric patients with heart murmurs or chest pain?

OBJECTIVES

To determine the usefulness of electrocardiography (ECG) and chest radiography (CXR) in evaluation of patients referred to the pediatric cardiologist for the evaluation of heart murmur or chest pain.

DESIGN

In this prospective study, 106 consecutive outpatients were categorized with no heart disease, possible heart disease, or definite heart disease based on history and physical examination; they then underwent ECG and CXR. Studies were reviewed and the examining cardiologist could change the diagnosis and order an echocardiogram.

SETTING

Academic pediatric cardiology practice.

RESULTS

In patients thought to have no heart disease, the diagnosis was changed to definite heart disease in four solely on the basis of abnormal CXR or ECG. In 25 patients thought to have possible heart disease, the diagnosis was changed to no heart disease (7) or definite heart disease (5) after review of the CXR and ECG. All 25 patients diagnosed with definite heart disease had this confirmed by abnormal CXR (2), ECG (3), both abnormal CXR and ECG, or echocardiogram (18).

CONCLUSIONS

ECG and CXR helped diagnose heart disease in four patients thought to have no heart disease, helped to rule out lesions in seven patients with possible heart disease, helped diagnose heart disease in five patients thought to have possible heart disease, and helped confirm heart disease in nine patients. In these days of cost containment, routine ECG and CXR continue to be valuable tools for the pediatric cardiologist in evaluation of patients with heart murmurs or chest pain.

Experience of FK506 immune suppression in pediatric heart transplantation: a study of long-term adverse effects

BACKGROUND

Immunosuppression with FK506 for pediatric heart transplantation has been used in this institution since 1989. This study reports the unique toxicity of this macrolide agent in these heart transplant recipients.

METHODS

Between October 1989 and August 1994, 49 patients were managed with FK506, which was the initial primary agent in 38 patients. The remaining 11 were switched from cyclosporine A because of persistent rejection or side effects from the cyclosporine A or prednisone. Data were obtained retrospectively from medical records.

RESULTS

Mean duration of follow-up was 29 months (median 37 months, range 3 to 96 months). Twenty-nine patients (59%) were receiving FK506 alone; 20 patients (41%) were receiving additional treatment with azathioprine, prednisone, or methotrexate. There were seven deaths. Twenty patients (41%) had elevated creatinine levels between 1 to 2 mg/dl. Five patients (11%) had levels greater than 2 mg/dl. Two patients with preexisting renal dysfunction while receiving cyclosporine A had chronic renal failure 32 and 36 months after switching to FK506 and required kidney transplantation. Hyperkalemia was a persistent finding in 26 patients. Of eight patients with hypertension, four had preexisting disease while receiving cyclosporine A; two had impaired renal function, and two were receiving prednisone. Severe anemia developed in eight patients (16%), two of whom had parvovirus. Moderate anemia developed in 21 patients (43%). Eosinophilia occurred in 19 patients; 11 of 19 patients (58%) had allergic symptoms. There was one case of diabetes mellitus. There were 12 significant infections with four infection-related deaths. Lymphoproliferative disease was noted in three patients, two of whom survived. Gastrointestinal symptoms, including chronic diarrhea, recurrent abdominal pain, and reflux esophagitis were present in 10 patients.

CONCLUSIONS

In our experience, anemia, renal toxicity, hyperkalemia, chronic diarrhea, and allergies were the most common adverse effects of FK506. Unlike cyclosporine A, hypertension, gingival hyperplasia, coarsening of facial features, and hirsutism were not seen.

Alcohol consumption and health: synergistic interaction with personality

In this study, 6,386 males and 5,990 females, with a mean age of 55 years, constituting a random sample, were administered questionnaires by interviewers relating to amount of self-regulation and drinking status. They were then followed up over a 20-yr. period, and health status (living well, chronically ill, or deceased) was ascertained. It was hypothesized that the deleterious effect of alcohol would be worse for those low on self-regulation; that health status would be worse for those in whom drinking diminished self-regulation, as compared with those for whom drinking improved self-regulation; and that smoking would have greater effects in lowering health status in those in whom drinking diminished self-regulation than in those in whom drinking improved self-regulation. All predictions were borne out by the data at high statistical significance. The results confirmed findings from an earlier study to the effect that psychological factors like self-regulation powerfully influence the kind of effects drinking has with respect to health.

Method of test administration as a factor in test validity: the use of a personality questionnaire in the prediction of cancer and coronary heart disease

This study examines the predictive accuracy of four different methods of administration of a questionnaire designed to predict cancer and coronary heart disease (CHD) in healthy probands. The method of administration uses the establishment of trust and the explanation of questions as variables in all four possible combinations, i.e. trust and explanation, trust only, explanation only, and neither, the prediction being that the combination of trust and explanation would produce the most accurate prediction, the treatment using neither the worst prediction, with methods using either trust alone or explanation alone intermediate. The criterion was the successful prediction of cancer and CHD. A total population of 3563 men and women was used, and followed up over 15 years, death certificates being used to establish cause of death. As predicted, the combination of trust and explanation did best, use of neither worst. Explanation seemed more important than trust, and the combination seemed to have a synergistic effect. It is apparent that method of administration had an important effect on the outcome of the experiment.

Use of the Booklet Category Test to assess abstract concept formation in schizophrenic disorders

The relationship of concept formation abilities to the presence or absence of delusions in schizophrenic disorders was investigated. Twenty-six schizophrenic patients and 14 normal individuals were administered a short form of the Booklet Category Test (BCT). Patients were grouped into those with and without delusions. It was hypothesized that the delusional group would perform significantly better on the BCT (obtain lower error scores) than the nondelusional group. Normal and delusional groups obtained significantly lower BCT error scores than the nondelusional group, even when differences in IQ scores were statistically partialled out. The two schizophrenic groups also differed significantly on BCT error scores with the delusional group performing better than the nondelusional group.

A structural model of the dimensions of teacher stress

A comprehensive survey of teacher stress, job satisfaction and career commitment among 710 full-time primary school teachers was undertaken by Borg, Riding & Falzon (1991) in the Mediterranean islands of Malta and Gozo. A principal components analysis of a 20-item sources of teacher stress inventory had suggested four distinct dimensions which were labelled: Pupil Misbehaviour, Time/Resource Difficulties, Professional Recognition Needs, and Poor Relationships, respectively. To check on the validity of the Borg et al. factor solution, the group of 710 teachers was randomly split into two separate samples. Exploratory factor analysis was carried out on the data from Sample 1 (N = 335), while Sample 2 (N = 375) provided the cross-validational data for a LISREL confirmatory factor analysis. Results supported the proposed dimensionality of the sources of teacher stress (measurement model), along with evidence of an additional teacher stress factor (Workload). Consequently, structural modelling of the 'causal relationships' between the various latent variables and self-reported stress was undertaken on the combined samples (N = 710). Although both non-recursive and recursive models incorporating Poor Colleague Relations as a mediating variable were tested for their goodness-of-fit, a simple regression model provided the most parsimonious fit to the empirical data, wherein Workload and Student Misbehaviour accounted for most of the variance in predicting teaching stress.

Role of right ventricular endomyocardial biopsy in infants and children with suspected or possible myocarditis

OBJECTIVES

To assess the diagnostic yield, sampling errors, risks, and therapeutic implications of right ventricular endomyocardial biopsy in children with suspected or possible myocarditis.

DESIGN

Retrospective study.

SETTING

Tertiary referral centre for paediatric cardiology, cardiac surgery, heart transplantation, and mechanical circulatory support.

PATIENTS AND METHODS

Review of clinical and histological findings among 63 consecutive children with possible myocarditis undergoing right ventricular endomyocardial biopsy. Review of cardiac histology at subsequent necropsy or after explantation at time of transplantation.

RESULTS

From January 1980 to December 1992, 76 biopsies were performed in 63 children (2 weeks to 18 years of age). In 41 cases, the biopsy was performed for evaluation of dilated cardiomyopathy. The median interval from onset of symptoms was one month. Eight children (20%; all with a history of less than six weeks duration) had biopsy proved myocarditis. Five of the eight children made a full recovery, including four who presented in cardiogenic shock. By contrast, only three of 33 children without evidence of myocarditis showed recovery of ventricular function. The whole heart was available for histological examination in 23 patients. Myocarditis was confirmed in one patient, and no evidence of myocarditis was found in the remaining 22 (all with negative biopsies). One procedure related death occurred in a 2 week old infant with dilated cardiomyopathy. In 22 cases, biopsy was performed for the evaluation of arrhythmia. Only one biopsy showed myocarditis.

CONCLUSIONS

The diagnostic yield of a biopsy is low in children with arrhythmias. In children presenting with profound ventricular dysfunction, a diagnosis of acute myocarditis may avoid premature consideration of transplantation as this group has an important potential for full recovery. In less critically ill patients and in those with a longer duration of symptoms the justification for biopsy is not as clear and the procedure is not without risk.

Psychometric properties of Russell's short form of the Booklet Category Test

Russell's short form of the Booklet Category Test was administered to 26 diagnosed schizophrenic patients and 14 normal individuals along with a test of premorbid intelligence. IQ correlated significantly (inversely) with errors and in particular with Subtests 3, 4, and 6. Age related directly to errors, especially for Subtests 3, 4, and 5. The mean Cronbach coefficient alpha was .71, indicating moderate item homogeneity across subtests. In sum, the shortened form appears to be an efficient and effective measure of concept formation among schizophrenic individuals.

Aerobic exercise, mood states and menstrual cycle symptoms

This study examined the effects of regular, moderate exercise on mood states and menstrual cycle symptoms. A group of female regular exercisers (N = 97), and a second group of female nonexercisers (N = 159), completed the Menstrual Distress Questionnaire (MDQ) and the Differential Emotions Scale (DES-IV) premenstrually, menstrually and intermenstrually. Multivariate analyses of covariance (MANCOVAs) revealed significant effects for exercise on negative mood states and physical symptoms, and significant effects on all measures across menstrual cycle phase. The regular exercisers obtained significantly lower scores on impaired concentration, negative affect, behaviour change and pain. No differences were found between groups on positive affect and other physical symptoms.

Children's Motivation Analysis Test (CMAT)--normative data

N-stens for 475 Australian children in Grade 6 and for boys and girls separately are presented for the Children's Motivation Analysis Test, representing the first such normative data available for this instrument.

Are employment-interview skills a correlate of subtypes of schizophrenia?

46 inpatients with a DSM-III diagnosis of schizophrenia were assessed in the week prior to discharge from hospital on measures of positive and negative symptoms and on 12 measures of employment interview skills (i.e., eye contact, facial gestures, body posture, verbal content, voice volume, length of speech, motivation, self-confidence, ability to communicate, manifest adjustment, manifest intelligence, over-all interview skill), and a global measure of employability. A cluster analysis based on the total positive and negative symptom scores produced two groups. The group with the lower mean negative symptom score exhibited better employment-interview skills and higher ratings on employability.

Sex differences in the prediction of academic achievement using the Children's Motivation Analysis Test

The Children's Motivation Analysis Test (CMAT), together with standardised achievement tests in mathematics and reading, was administered to a large sample of Australian elementary school children. Stepwise forward regression analyses were conducted on subsamples of 209 males and 179 females (cases with missing data previously excluded). Several of the CMAT dynamic traits significantly predicted achievement scores. The most useful predictors were conscientiousness (Superego) and family (Home) orientation. These results, based on objective motivation measurement, represent the beginnings of a new approach for research into children's motivation structure.

Which employment interview skills best predict the employability of schizophrenic patients?

To examine the effects of verbal and nonverbal interview microbehaviors and interview characteristics on employability, Simulated Employment Interviews were conducted with 46 psychiatric inpatients who each met the DSM-III criteria for a diagnosis of schizophrenia. Each interview was videotaped and shown to two raters, who generated independent ratings for six microbehaviors (eye-contact, facial gestures, body posture, verbal content, voice volume, and length of speech) and six subject characteristics (motivation, self-confidence, ability to communicate, manifest adjustment, manifest intelligence and overall interview skill). A panel of three Commonwealth Employment Service psychologists viewed the same videotaped interviews and generated employability ratings. Verbal and nonverbal microbehaviors were relatively independent while subject characteristics were highly interdependent. Microbehaviors and characteristics correlated at a high level. Of the 12 interview microbehaviors and characteristics, manifest adjustment and ability to communicate accounted for 64% of the total variance in predicting employability. Interviewees who were perceived as behaving in an adjusted manner and as being good communicators were rated as more employable.

What does the neuropsychological category test measure?

The Halstead Category Test of brain dysfunction is one of the most sensitive neuropsychological measures currently available. While the instrument has received widespread use, nevertheless, the exact nature of what it measures has been poorly delineated. The present brief report presents the results of separate factor analyses of the Category Test along with other neuropsychological measures from the Halstead-Reitan battery. Despite considerable differences in samples, as well as in the particular neuropsychological measures included in the separate analyses, the Category Test consistently lined-up with general intellectual and memory components, in each instance.

Clinical neuropsychological assessment: abbreviating the Halstead Category Test of brain dysfunction

The present paper reports both quantitative and qualitative data on an abbreviated 84-item version of the Halstead Category Test (HCT) (N = 51). The HCT is a sensitive indicator of organic brain impairment and is included as part of the important Halstead-Reitan neuropsychological test battery. Unfortunately, the HCT is burdened by excessive length and may take up to 2 hours to administer to brain-damaged patients. While a number of attempts to reduce the length and concomitant administration time of the HCT have been reported in the Journal of Consulting and Clinical Psychology over recent years, none of these studies has resulted in a sufficiently shortened HCT to allow practical application with many brain-damaged patients. The proposed version of the HCT takes only 10 to 15 minutes to administer and leaves enough items from the full HCT to enable a parallel form to be developed.

Self-report measures of depression: some psychometric considerations

This paper examines some aspects of the psychometric adequacy of existing self-report depression measures, so that clinicians might better appreciate their reliability and validity. Issues addressed include the desirability of moderate rather than maximum test-retest and item homogeneity/internal consistency estimates; the distinction between measurement at the surface syndrome level vs. that at the fundamental source state/trait level; the importance of appropriate rather than arbitrary factor analytic procedures; and the need for multivariate measures instead of the single-scale instruments so often employed to measure depression in isolation from interacting emotions such as anxiety or stress. Apart from these more general issues, a number of specific criticisms is considered, along with recommendations for better self-report measures of depression.