Setting up regional diagnostic reference levels for pediatric interventional cardiology in Latin America and the Caribbean countries: preliminary results and identified challenges

The goal of the present study was to propose a set of preliminary regional diagnostic reference levels (DRLs) for pediatric interventional cardiology (IC) procedures in Latin America and the Caribbean countries, classified by age and weight groups. The study was conducted in the framework of the Optimization of Protection in Pediatric Interventional Radiology in Latin America and the Caribbean program coordinated by the World Health Organization and the Pan American Health Organization in cooperation with the International Atomic Energy Agency. The first step of the program was focused on pediatric IC. Dose data from diagnostic and therapeutic procedures were collected between December 2020 and December 2021. Regional DRLs were set as the third quartile of patient dose data (kerma area product) collected in 18 hospitals from 10 countries in an initial sample of 968 procedures. DRLs were set for four age bands and five weight ranges. The values obtained for the four age bands (<1 yr, 1 to <5 yr, 5 to <10 yr and 10 to <16 yr) were 2.9, 6.1, 8.8 and 14.4 Gy cm²for diagnostic procedures, and 4.0, 5.0, 10.0 and 38.1 Gy cm²for therapeutic procedures, respectively. The values obtained for the five weight bands (<5 kg, 5 to <15 kg, 15 to <30 kg, 30 to <50 kg and 50 to <80 kg) were 3.0, 4.5, 8.1, 9.2 and 26.8 Gy cm²for diagnostic procedures and 3.7, 4,3, 7.3, 16.1 and 53.4 Gy cm²for therapeutic procedures, respectively. While initial data were collected manually as patient dose management systems (DMSs) were not available in most of the hospitals involved in the program, a centralized automatic DMS for the collection and management of patient dose indicators has now been introduced and is envisaged to increase the sample size. The possibility of alerting on high dose values and introducing corrective actions will help in optimization.

Sustained cellular immune dysregulation in individuals recovering from SARS-CoV-2 infection

SARS-CoV-2 causes a wide spectrum of clinical manifestations and significant mortality. Studies investigating underlying immune characteristics are needed to understand disease pathogenesis and inform vaccine design. In this study, we examined immune cell subsets in hospitalized and nonhospitalized individuals. In hospitalized patients, many adaptive and innate immune cells were decreased in frequency compared with those of healthy and convalescent individuals, with the exception of an increase in B lymphocytes. Our findings show increased frequencies of T cell activation markers (CD69, OX40, HLA-DR, and CD154) in hospitalized patients, with other T cell activation/exhaustion markers (PD-L1 and TIGIT) remaining elevated in hospitalized and nonhospitalized individuals. B cells had a similar pattern of activation/exhaustion, with increased frequency of CD69 and CD95 during hospitalization followed by an increase in PD1 frequencies in nonhospitalized individuals. Interestingly, many of these changes were found to increase over time in nonhospitalized longitudinal samples, suggesting a prolonged period of immune dysregulation after SARS-CoV-2 infection. Changes in T cell activation/exhaustion in nonhospitalized patients were found to positively correlate with age. Severely infected individuals had increased expression of activation and exhaustion markers. These data suggest a prolonged period of immune dysregulation after SARS-CoV-2 infection, highlighting the need for additional studies investigating immune dysregulation in convalescent individuals.

Photodepletion with 2-Se-Cl prevents lethal graft-versus-host disease while preserving antitumor immunity

Acute graft-versus-host-disease (GVHD), limits the use of hematopoietic cell transplant (HCT) to treat a variety of malignancies. Any new therapeutic approach must satisfy three requirements: 1) Prevent GVHD, 2) Maintain anti-pathogen immunity, and 3) Maintain anti-tumor immunity. In prior studies we have shown that the selective photosensitizer 2-Se-Cl eliminates highly alloreactive lymphocytes from the graft prior to HCT preventing GVHD and that antiviral immune responses were preserved following incubation with 2-Se-Cl. In this report, we investigated whether 2-Se-Cl treatment preserves antitumor immunity, and then used high dimensional flow cytometry to identify the determinants of successful immune reconstitution. Donor C57BL/6 splenocytes were cocultured for 4 days with irradiated BALB/c splenocytes and then exposed to 2-Se-Cl. Photodepletion (PD)-treated splenocytes were then infused into lethally irradiated BALB/c mice inoculated with A20 leukemia/lymphoma cells. Recipient mice that received PD-treated splenocytes survived > 100 days without evidence of GVHD or leukemia. In contrast, mice that did not receive PD-treated cells at time of HCT died of leukemia progression. Multiparameter flow cytometry of cytokines and surface markers on peripheral blood samples 15 days after HCT demonstrated unique patterns of immune reconstitution. We found that before clinical disease onset GVHD was marked by functionally exhausted T cells, while tumor clearance and long-term survival were associated with an expansion of polyfunctional T cells, monocytes, and DCs early after transplantation. Taken together these results demonstrate that 2-Se-Cl photodepletion is a new treatment that can facilitate HCT by preventing GVHD while preserving antiviral and anti-tumor immunity.

A copper-dependent compound restores ampicillin sensitivity in multidrug-resistant Staphylococcus aureus

Multi-drug resistant Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), has become a worldwide, major health care problem. While initially restricted to clinical settings, drug resistant S. aureus is now one of the key causative agents of community-acquired infections. We have previously demonstrated that copper dependent inhibitors (CDIs), a class of antibiotics that are only active in the presence of copper ions, are effective bactericidal agents against MRSA. A second-generation CDI, APT-6K, exerted bactericidal activity at nanomolar concentrations. At sub-bactericidal concentrations, it effectively synergized with ampicillin to reverse drug resistance in multiple MRSA strains. APT-6K had a favorable therapeutic index when tested on eukaryotic cells (TI: > 30) and, unlike some previously reported CDIs, did not affect mitochondrial activity. These results further establish inhibitors that are activated by the binding of transition metal ions as a promising class of antibiotics, and for the first time, describe their ability to reverse existing drug resistance against clinically relevant antibiotics.

Proximal Femoral Nail Antirotation versus Gamma3 nail for intramedullary nailing of unstable trochanteric fractures. A randomised comparative study

The purpose of this study was to compare the clinical results and the complication rates of a new generation of two intramedullary fixation devices: Proximal Femoral Nail Antirotation® (PFNA) and Gamma3®. We conducted a prospective randomised multicentre trial of 61 patients who underwent a PFNA fixation treatment (31 patients) or a Gamma3 nail (30 patients). We documented the fixation failure complications as well as data of the surgical procedure, the clinical and functional outcomes (the EuroQoL5 questionnaire, the Katz index score, the Short Form 36 (SF-36), and the Harris Hip Score) and the plain radiographic parameters at 3,6 and 12 months follow up. The PFNA and Gamma3 fixation devices were similar in terms of complication rates. The risk for experiencing a postoperative complication after Gamma3 nailing was 40% versus 45% after PFNA fixation. At the 6-month and 1-year follow-up evaluations, there were no significant differences in terms of range of motion, clinical scores and radiological outcomes.

Detection of Clostridium tyrobutyricum spores using polyclonal antibodies and flow cytometry

AIMS

The present work investigates the feasibility of using flow cytometry (FCM) combined with fluorescent-labelled specific polyclonal antibodies for the detection and presumptive identification of Clostridium tyrobutyricum spores in bovine milk.

METHODS AND RESULTS

Two fluorescent molecules (fluorescein isothiocyanate and Alexa Fluor 488) were conjugated to antispores polyclonal antibodies. Side scatter and forward scatter profiles of the Cl. tyrobutyricum spores marked with fluorescent antibodies permitted the detection of spores and differentiated them from other related microbial species. The detection limit of this method was 10(3) spores per 100 ml of milk, and results could be achieved in 2 h.

CONCLUSIONS

FCM combined with fluorochrome-conjugated antibodies, especially Alexa Fluor, could be an efficacious means to detect and provide presumptive identification of Cl. tyrobutyricum spores, as well as differentiation from other Clostridium species that can also cause late blowing in cheese.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study describes the basis for the development of a method suitable for analysis of milk destined for cheese manufacture that would permit the detection of Cl. tyrobutyricum spores in a short period. This would enable the industry to use contaminated milk for dairy products other than cheese where Cl. tyrobutyricum does not cause a problem.

The Cutaneous Assessment Tool: development and reliability in juvenile idiopathic inflammatory myopathy

OBJECTIVES

Clinical care and therapeutic trials in idiopathic inflammatory myopathies (IIM) require accurate and consistent assessment of cutaneous involvement. The Cutaneous Assessment Tool (CAT) was designed to measure skin activity and damage in IIM. We describe the development and inter-rater reliability of the CAT, and the frequency of lesions endorsed in a large population of juvenile IIM patients.

METHODS

The CAT includes 10 activity, 4 damage and 7 combined lesions. Thirty-two photographic slides depicting IIM skin lesions were assessed by 11 raters. One hundred and twenty-three children were assessed by 11 paediatric rheumatologists at 10 centres. Inter-rater reliability was assessed using simple agreements and intra-class correlation coefficients (ICC).

RESULTS

Simple agreements in recognizing lesions as present or absent were generally high (0.5-1.0). ICCs for CAT lesions were moderate (0.4-0.75) in both slides and real patients. ICCs for the CAT activity and damage scores were 0.71 and 0.81, respectively. CAT activity scores ranged from 0 to 44 (median 7, potential range 0-96) and CAT damage scores ranged from 0 to 13 (median 1, potential range 0-22). The most common cutaneous lesions endorsed were periungual capillary loop changes (63%), Gottron's papules/sign (53%), heliotrope rash (49%) and malar/facial erythema (49%).

CONCLUSIONS

Total CAT activity and damage scores have moderate to good reliability. Assessors generally agree on the presence of a variety of cutaneous lesions. The CAT is a promising, semi-quantitative tool to comprehensively assess skin disease activity and damage in IIM.

Dosimetry of small electron fields shaped by lead

Electron radiotherapy fields are commonly used to treat superficial cancers. Field shaping can be achieved by placing lead on the patient surface to minimise the dose to surrounding areas. However, significant dosimetry changes under high density material edges for electron fields have been reported in the literature. This project evaluated the dosimetry of small dimension electron fields shaped with lead placed on the surface. Comparisons were made between circular lead cutouts placed on the skin and low melting point alloy cutouts placed in an applicator. Depth doses, profiles and output factors were measured using a diode detector in a water phantom. Film was also used to determine surface dose delivered when the lead cutouts were placed on the surface. Minimal differences were observed between the different setups for the depth dose curves, although significant differences were seen in the penumbra and the surface doses. The penumbra is smaller for the lead cutouts placed on the surface, however, significant dose increases at the edge of the field were observed for larger fields and energies; this may result in undesirable clinical effects.

Z score prediction model for assessment of bone mineral content in pediatric diseases

The objective of this study was to develop an anthropometry-based prediction model for the assessment of bone mineral content (BMC) in children. Dual-energy X-ray absorptiometry (DXA) was used to measure whole-body BMC in a heterogeneous cohort of 982 healthy children, aged 5-18 years, from three ethnic groups (407 European- American [EA], 285 black, and 290 Mexican-American [MA]). The best model was based on log transformations of BMC and height, adjusted for age, gender, and ethnicity. The mean +/- SD for the measured/predicted in ratio was 1.000 +/- 0.017 for the calibration population. The model was verified in a second independent group of 588 healthy children (measured/predicted In ratio = 1.000 +/- 0.018). For clinical use, the ratio values were converted to a standardized Z score scale. The whole-body BMC status of 106 children with various diseases (42 cystic fibrosis [CF], 29 juvenile dermatomyositis [JDM], 15 liver disease [LD], 6 Rett syndrome [RS], and 14 human immunodeficiency virus [HIV]) was evaluated. Thirty-nine patients had Z scores less than -1.5, which suggest low bone mineral mass. Furthermore, 22 of these patients had severe abnormalities as indicated by Z scores less than -2.5. These preliminary findings indicate that the prediction model should prove useful in determining potential bone mineral deficits in individual pediatric patients.

Specific immunoglobulins in serum of newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG

The apparent efficiency of absorption and the decrease of specific colostral IgG after its passage into the blood stream were determined in newborn lambs fed with a single dose of colostrum containing anti-peroxidase IgG at 30 minutes, 12 hours and 24 hours after birth. When colostrum was given at 30 minutes after birth, a value of 16.9+/-4.0 per cent of anti-peroxidase IgG ingested appeared in lamb circulation. This percentage was reduced to 9.8+/-0.8 per cent when the feeding was done at 12 hours after birth and no specific IgG was detected in lambs fed at 24 hours after birth. The concentration of anti-peroxidase IgG in lambs' serum declined quickly within 96 hours of age to about 48 per cent of the initial value, and afterwards the level decreased slowly reaching a value of 10 per cent at 32 days of age. This behaviour probably reflects the protein distribution and use of absorbed antiperoxidase IgG.

Hyperfractionated chemoradiation with carbogen breathing, with or without erythropoietin: a stepwise developed treatment schedule for advanced head-and-neck cancer

PURPOSE

To investigate the influence of carbogen breathing on chemoradiation and the effects of erythropoietin on transfusions.

METHODS AND MATERIALS

From March 1996 to April 2000, 42 (4 Stage III and 38 Stage IV) patients with head and neck cancer were treated with a twice-a-day hyperfractionated schedule. Each fraction consisted of 5 mg/m(2) of carboplatin plus 115 cGy with carbogen breathing. Treatment was given 5 days per week up to total doses of 350 mg/m(2) of carboplatin plus 8050 cGy in 7 weeks. Anemia was treated either by transfusion or by erythropoietin.

RESULTS

Forty-one patients tolerated the treatment as scheduled. All patients tolerated the planned radiation dose. Five transfusions were given in the first group, but no transfusion was needed in the erythropoietin group. Local toxicities remained at the level expected with irradiation alone. Chemotherapy toxicity was moderate. Forty-two complete responses were achieved. At two years actuarial local control, cause-specific survival and overall survival are respectively 85%, 69%, and 68%. At four years estimated probabilities of local control, cause-specific survival and overall survival are also 85%, 69%, and 68%.

CONCLUSIONS

These results compare favorably with those of most reported studies. The addition of carbogen breathing appears to improve the results of chemoradiation alone. Erythropoietin therapy avoided transfusions.

Validation of the Childhood Health Assessment Questionnaire in the juvenile idiopathic myopathies. Juvenile Dermatomyositis Disease Activity Collaborative Study Group

OBJECTIVE

To examine the validity of the Childhood Health Assessment Questionnaire (CHAQ) in patients with juvenile idiopathic inflammatory myopathy (IIM).

METHODS

One hundred fifteen patients were enrolled in a multicenter collaborative study, during which subjects were assessed twice, 7-9 months apart. Physical function was measured using the CHAQ. Internal reliability was assessed using adjusted item-total correlations and item endorsement rates. Construct validity was assessed by comparing predicted and actual correlations of the CHAQ with other measures of physical function and disease activity. Responsiveness was assessed by calculating effect size (ES) and standardized response mean (SRM) in a group of a priori defined "improvers."

RESULTS

Item-total correlations were high (rs range = 0.35-0.81), suggesting all items were related to overall physical function. Manual muscle testing and the Childhood Myositis Assessment Scale correlated moderate to strongly with the CHAQ (r = -0.64 and -0.75, both p < 0.001). Moderate correlations were also seen with the physician global assessment of disease activity (rs = 0.58, p < 0.001), parent global assessment of overall health (rs = -0.65, p < 0.001), Steinbrocker function class (rs = 0.69, p < 0.001), and global skin activity (rs = 0.40, p < 0.001), while global disease damage and skin damage had low correlations (rs = 0.13 and 0.07, p > or =0.17). Responsiveness of the CHAQ was high, with ES = 1.05 and SRM = 1.20.

CONCLUSION

In this large cohort of patients with juvenile IIM, the CHAQ exhibited internal reliability, construct validity, and strong responsiveness. We conclude that the CHAQ is a valid measure of physical function in juvenile IIM, appropriate for use in therapeutic trials, and potentially in the clinical care of these patients.

Effects of rheumatic disease and corticosteroid treatment on calcium metabolism and bone density in children assessed one year after diagnosis, using stable isotopes and dual energy x-ray absorptiometry

OBJECTIVE

To evaluate calcium (Ca) metabolism and bone mineral density (BMD) in children with rheumatic disease (RD) at diagnosis and one year later, and effects of different therapies.

METHODS

We used dual tracer isotope studies and dual energy x-ray absorptiometry (DEXA) to measure Ca metabolism and BMD in 13 children with RD at diagnosis and one year later. Seven subjects were treated with steroids (RD-ST), 6 with antiinflammatory agents (RD-NS), excluding steroids.

RESULTS

Ca balance data for RD subjects were not significantly different from data reported previously for healthy sex and age matched controls. True Ca absorption (Va) was slightly but not significantly greater at study entry in RD-NS subjects (313+/-67 vs 239+/-112 mg/day in RD-ST subjects; p = 0.13). Calculated Ca balance retention (Vbal) was higher at entry in RD-NS (200+/-51 vs RD-ST 60+/-125 mg/day; p = 0.08). One year later, Vbal remained higher in RD-NS (202+/-77 mg/day vs RD-ST 101+/-157 mg/day; p = 0.02). BMD was similar in both groups at entry (RD-NS 0.81+/-0.06 g/cm2 vs RD-ST 0.89+/-0.1 g/cm2; p = 0.07). One year later, BMD was 0.86+/-0.6 g/cm2 in RD-NS versus 0.89+/-0.08 g/cm2 in RD-ST; p = 0.07. Ca kinetic and DEXA studies did not reveal significant alteration of Ca kinetics or significantly lower BMD in steroid treated subjects versus non-steroid treated subjects. However, slightly lower Va and Vbal indicated a possible risk of bone demineralization in steroid treated subjects.

CONCLUSION

Children with RD who are treated with steroids may be at greater risk of bone demineralization at diagnosis that persists through the first year. However, bone loss may take years to manifest when measured by quantitative methods such as DEXA.

Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies. II. The Childhood Myositis Assessment Scale (CMAS): a quantitative tool for the evaluation of muscle function. The Juvenile Dermatomyositis Disease Activity Collaborative Study Group

OBJECTIVE

To develop, validate, and determine the measurement characteristics of a quantitative tool for assessing the severity of muscle involvement in children with idiopathic inflammatory myopathies.

METHODS

The Childhood Myositis Assessment Scale (CMAS) was developed from 2 existing observational functional assessment tools to assess muscle function in the areas of strength and endurance across a wide range of ability and ages. The 14 ordinal items included were chosen to assess primarily axial and proximal muscle groups and are ranked with standard performance and scoring methods. Following the development of the CMAS, a training video and written instructions were developed and reviewed by the physicians participating in this study. Subsequently, utilizing a randomized block design, 12 physicians independently scored 10 children (9 with dermatomyositis, 1 with polymyositis; ages 4-15 years) twice in one day (morning and afternoon) on the CMAS. A pediatric physical therapist performed quantitative manual muscle strength testing (MMT) twice on each child (morning and afternoon), including the neck, trunk, and proximal and distal extremity muscle groups.

RESULTS

The CMAS has a potential range of 0-51, with higher scores indicating greater muscle strength and endurance. The observed mean for the 10 patients was 36.4 (median 44, SD 14.1, observed range 5-51). The total score for the CMAS correlated with the physician's global assessment (by visual analog scale) of disease activity, the MMT score, serum creatine kinase level, and the Juvenile Arthritis Functional Assessment Report score. The score on the CMAS was not correlated with patient age. Interrater reliability (Kendall's coefficient of concordance) ranged from 0.77 to 1.0 for individual items (all P < 0.001), and overall, it was 0.95 (P < 0.001). Intrarater reliability for the individual physicians was measured by correlation of the CMAS scores for each patient on 2 separate evaluations and ranged from 0.97 to 0.99, with an overall correlation for all physicians of 0.98 (all P < 0.001).

CONCLUSION

The CMAS demonstrated an acceptable range of observed scores, excellent convergent validity, and excellent inter- and intrarater reliability. The CMAS is validated to quantitatively assess muscle function in the areas of strength and endurance in children with idiopathic inflammatory myopathies. It can be used in routine clinical care as well as therapeutic trials.

Improved outcome of cytomegalovirus retinitis in AIDS patients after introduction of protease inhibitors

The objective of this study was to evaluate the influence of protease inhibitor therapy on the rate of progression and survival of 17 AIDS patients with stable Cytomegalovirus retinitis, who were receiving anti-CMV therapy. CD4+ count, HIV load, and CMV antigenemia assay were determined at baseline, at the first month, and every 3 months thereafter. Median CD4+ count increased from 11 to 87 cells/mm3, and median HIV RNA level decreased from 4.96 to 3.28 log10 copies/ml, after 6 months on therapy. Although 9 patients (53%) relapsed in a median time of 97 days (range, 15-152 days), no further episodes were observed during a median follow-up of 17 months (range, 5-18 months). Thus, the probability of remaining free of relapse was twofold higher than that observed in matched patients who did not receive protease inhibitors. Median CD4+ count at the 3rd month was higher in those individuals who went on to progress (p = .03), and a positive result to a CMV antigenemia test was associated with progression of retinitis (relative hazard, 4.45; p = .04). Survival rate was 94% at 17 months (89% increase). Therefore, protease inhibitor therapy reduces retinitis progression and improves survival. However, the immunologic response may not provide initial sufficient protection to avoid, or even may play a role on, early CMV progression.

Chemotherapy as a part of each treatment fraction in a twice-a-day hyperfractionated schedule: a new chemoradiotherapy approach for advanced head and neck cancer

BACKGROUND

Using chemotherapy as a part of each treatment fraction remains unexplored. This study integrates the concomitant administration of carboplatin with hyperfractionated irradiation by optimizing chemopotentiation through carboplatin administration with each irradiation fraction.

METHODS

From February 1993 to August 1996, 52 patients with advanced head and neck cancer were treated on a twice-a-day chemoradiotherapy schedule. Each fraction consisted of 115 cGy preceded by 5 mg/m2 of carboplatin. Treatment was given 5 days a week up to total doses of 350 mg/m2 of carboplatin + 8050 cGy in 7 weeks.

RESULTS

All (100%) of patients tolerated the treatment (83% as scheduled). Acute and late toxicities were moderate. Rates of 96% complete response (CR) and 4% partial response (PR) were achieved. At 52 months, local control and cause-specific survival rates are 72% and 59%, respectively. Nodal control rate is 95%.

CONCLUSION

These results show potential for improvement upon hyperfractionated radiotherapy alone and compare favorably with those of most reported trials.

Increasing incidence of childhood class V lupus nephritis

OBJECTIVE

Class V lupus nephritis (LN) is reported to occur in 0-23% of patients with LN. To better characterize pediatric LN, we determined at a single center (1) the relative frequency of Class V LN on first and serial biopsies, (2) the frequency of transformation between LN classes on serial biopsies, (3) types of treatment received and outcome to date of different classes of LN.

METHODS

All pediatric renal biopsies from 1985 to the present performed for diagnosis and classification of suspected LN were reviewed. Biopsy results were grouped into 2-3 year time intervals to assess trends in the distribution of WHO class diagnoses over time.

RESULTS

Sixty patients underwent 97 renal biopsies. Class V LN was present in 28% (17/60) of patients on first biopsy, and in 37% (22/60) on most recent biopsy. Class V LN on first biopsy increased from 17% (8/46) before 1995 to 64% (9/14) after 1995 (p < 0.001). Age at presentation, age at biopsy, time to biopsy, and types of treatment did not differ before and after 1995. Transformation to Class V LN occurred in 19% (5/27) of patients having repeat biopsies. No transformation from Class V LN occurred on repeat biopsy. Renal outcome was available in 48 patients with followup of 4.7 +/- 3.2 years for Class V LN, and 5.2 +/- 2.4 years for non-Class V LN. Five percent (1/20) of Class V LN patients had renal dysfunction or had died compared to 21% (6/28) of non-Class V LN patients (p = NS).

CONCLUSION

We found (1) a greater frequency of Class V LN than has been reported, (2) a recent increase in the incidence of Class V LN at our institution, (3) frequent transformation between classes on serial biopsies, and (4) no regression of Class V lesions in patients who had repeat biopsies.

Photon buildup in orthovoltage X-ray beams

Orthovoltage x-ray beams exhibit the characteristic of depth dose buildup which is not well described in the literature. The principal reason for this phenomenon is the increase in dose deposited due to electrons set in motion by secondary (Compton) scattered photons within the phantom, as depth is increased until longitudinal equilibrium is reached. This happens within a few millimetres of the surface and has been demonstrated both experimentally and by Monte Carlo methods. The Monte Carlo technique also enabled description of a second order primary dose buildup effect (due to longitudinal electronic disequilibrium) that would be impossible to detect with conventional detectors due to the short range of the electrons. The magnitude of buildup was observed to alter with various combinations of beam parameters. Variations will also occur with detectors used to measure buildup. It is recommended that radiation oncology departments assess this effect in the context of their clinical data in current use to ensure that there are not doses higher than prescribed being applied a few millimetres below the skin surface, especially if data was collected with a thin windowed, parallel plate ionisation chamber and/or that coarse steps for depth dose data collection were used along the beam central axis.

An independent check method of radiotherapy computer plan derived monitor units

With the increasing complexity of radiotherapy computer treatment planning systems (CTPS), verification of the treatments is an important component of a quality assurance program. The radiation dose delivered to a patient is based on treatment machine monitor units (MUs) that are calculated either using data tables or within the CTPS. An independent method for checking radiotherapy MU calculations is proposed. This method involves calculating the dose at a point (usually ICRU reference point) using the derived MUs and independently measured treatment data and comparing to the dose at the same point as predicted by the CTPS. A program was developed using Microsoft Excel to assist in performing this check. The program contains the beam data and various correction factors and calculates the dose after input of the treatment setup parameters. This independent method is used to check all radiotherapy treatment fields at Liverpool Hospital and has found a number of significant errors in the planning process and in the CTPS calculations.

Effect of heat treatment on the antigen-binding activity of anti-peroxidase immunoglobulins in bovine colostrum

After intramammary immunization with horseradish peroxidase, bovine colostrum containing anti-peroxidase immunoglobulins (Ig) was obtained. Thermoresistance of the antigen-binding region of these Ig was studied using a direct competitive ELISA. This technique is based on the competition between the anti-peroxidase IgG coated to the plate and the anti-peroxidase IgG contained in the colostrum to bind peroxidase, the antigen, and the enzyme responsible for development of the color of the assay. Thus, the degree of denaturation of the antigen-binding region in the IgG molecule can be determined because this region is directly involved in the assay. The kinetic and thermodynamic parameters for heat induced denaturation of IgG in colostrum were determined over a temperature range of 69 to 81 degrees C. The denaturation of IgG was best described assuming an apparent reaction order of 1.5. D values, the time required to reduce the antigen-binding activity of IgG by 90%, were 8504, 1387, 285, and 152 s at 69, 72, 77, and 81 degrees C, respectively. Similarly, Z value, the degrees necessary to reduce the D value in one logarithmic cycle, was estimated to be 6.6 degrees C, and the activation energy value was 386.83 kJ/mol. These results should be taken into account in the design of heat treatments of milk in order to preserve the biological function of Ig.

Development of validated disease activity and damage indices for the juvenile idiopathic inflammatory myopathies: I. Physician, parent, and patient global assessments. Juvenile Dermatomyositis Disease Activity Collaborative Study Group

OBJECTIVE

To determine the reliability, content validity, and responsiveness of physician global assessments of disease activity and damage in the juvenile idiopathic inflammatory myopathies (IIM), and to investigate concordance among physician, parent, and patient global ratings.

METHODS

Sixteen pediatric rheumatologists rated 10 juvenile IIM paper patient cases for global disease activity and damage, and assessed the importance of 51 clinical and laboratory parameters in formulating their global assessments. Then, 117 juvenile IIM patients were enrolled in a protocol to examine the relationship between Likert and visual analog scale global assessments, their sensitivity to change, and the comparability of physician, parent, and patient global ratings.

RESULTS

Pediatric rheumatologists demonstrated excellent interrater reliability in their global assessments of juvenile IIM disease activity and damage (97.7% and 94.7% agreement among raters, respectively), and agreed on a core set of clinical parameters in formulating their judgments. Likert scale ratings correlated with those on a visual analog scale, and both were comparable in responsiveness (standardized response means -0.56 for disease activity, 0.02 [Likert] and 0.14 [visual analog] for damage, measured over 8 months). Parent global ratings of disease activity correlated with physician assessments, but were not colinear (Spearman's correlation [r] = 0.41-0.45). Patient global disease activity assessments correlated with those done by parents (r = 0.57-0.84) and physicians (r = 0.37-0.63), but demonstrated less responsiveness (standardized response means -0.21 and -0.12, respectively, over 8 months).

CONCLUSION

Physician global assessments of juvenile IIM disease activity and damage demonstrated high interrater reliability and were shown to be comprehensive measures. Both physician and parent disease activity assessments should be considered valuable as quantitative measures for evaluating therapeutic responses in juvenile IIM patients.

The genes YNI1 and YNR1, encoding nitrite reductase and nitrate reductase respectively in the yeast Hansenula polymorpha, are clustered and co-ordinately regulated

The nitrite reductase-encoding gene (YNI1) from the yeast Hansenula polymorpha was isolated from a lambda EMBL3 H. polymorpha genomic DNA library, using as a probe a 481 bp DNA fragment from the gene of Aspergillus nidulans encoding nitrite reductase (niiA). An open reading frame of 3132 bp, encoding a putative protein of 1044 amino acids with high similarity with nitrite reductases from fungi, was located by DNA sequencing in the phages lambdaNB5 and lambdaJA13. Genes YNI1 and YNR1 (encoding nitrate reductase) are clustered, separated by 1700 bp. Northern blot analysis showed that expression of YNI1 and YNR1 is co-ordinately regulated; induced by nitrate and nitrite and repressed by sources of reduced nitrogen, even in the presence of nitrate. A mutant lacking nitrite reductase activity was obtained by deletion of the chromosomal copy of YNI1. The mutant does not grow in nitrate or in nitrite; it exhibits a similar level of transcription of YNR1 to the wild type, but the nitrate reductase enzymic activity is only about 50% of the wild type. In the presence of nitrate the delta ynil::URA3 mutant extrudes approx. 24 nmol of nitrite/h per mg of yeast (wet weight), about five times more than the wild type.

6MV x-ray dose in the build up region: empirical model and the incident angle effect

A simple and fast empirical model has been developed which accurately predicts central axis surface and build up dose for a 6MV radiotherapy x-ray beam. The model is based on fits to experimental data and accounts for open fields, block trays and wedges at normal incidence and at angle. The model separates the beam into components produced by primary photon interactions which have only interacted in the phantom at normal and oblique incidence and head scattered photons/electrons generated in the treatment head. The model quantifies these components for open unwedged fields and then the effect on each component by introducing beam modifying devices/ accessories or changing the angle of incidence is determined. Dose results at oblique incidence for Monte Carlo (electron contamination free) and experimental (electron contamination present) are sufficiently close to imply that the increase in build up dose with beam angle is mainly due to changes in photon interactions within the phantom and only a slight increase with angle is due to changes in the electron contamination. Electron contamination/ head scatter component was found to be measurable by three methods. These being TLD extrapolation in air, ionisation chamber measurements in air and Monte Carlo pure photon methods. These methods produced comparable electron contamination/head scatter dose results at all field sizes.

Calcium tracer kinetics show decreased irreversible flow to bone in glucocorticoid treated patients

Osteopenia resulting from pharmacologic doses of glucocorticoids is well known. Previously, there has been no satisfactory quantitative model describing the kinetics of calcium flow in subjects on chronic steroid use. A mathematical model of calcium isotope interaction with bone is described and applied to determine an estimate of kinetic parameters characterizing these changes. Calcium tracer dilution kinetics after a bolus injection of 42Ca were measured in 14 subjects with juvenile dermatomyositis, 6 on prednisone regimens and 8 on treatment regimens without prednisone. Irreversible tracer loss from plasma bone is found to be significantly reduced (P = 0.043) in the glucocorticoid-treated patients compared with patients on nonsteroid regimens. Reversible flow to bone is noted to be similar in the two groups. These results suggest a direct effect of glucocorticoids on osteoblast function.

Lack of platelet-activating factor release on acute myocardial ischemia in the isolated interventricular septum of rabbit heart

The effects of platelet-activating factor (PAF) on myocardial injury after 1 h global ischemia-30 min reperfusion were investigated in isolated arterially perfused interventricular septum of rabbit heart. PAF did not significantly affect developed tension, +/- dT/dtmax, resting tension and the times of active state in non-ischemic septa. The recovery of developed tension was significantly reduced by PAF (100 nM), after an ischemia-reperfusion challenge, from the control value of 20.9 +/- 3.5% to 10.5 +/- 1.8%, without a change in the resting tension (15.7 +/- 2.8 vs. 15.6 +/- 1.3 g). BN 52021 (20 microM), alone did not modify either parameter of ischemic damage, but antagonized the aggravating effect of PAF. Evidence of PAF activity was not found in any of the samples of the effluent perfusate obtained from ischemic control experiments. On the basis of the present results, we suggest a direct role for PAF in aggravating the myocardial damage induced by ischemia, and discard heart cells as the source of PAF in this state.

Uptake and passage of beta-lactoglobulin, palmitic acid and retinol across the Caco-2 monolayer

Caco-2 cell line grown on collagen coated polycarbonate membranes in bicameral chambers has been used to study the effect of the binding of palmitic acid or retinol on the uptake and passage of iodinated beta-lactoglobulin and albumin across cell monolayers. The percentage of beta-lactoglobulin transported through the monolayer was higher than that of albumin, about 50% and 30% of the total protein after 24 h of incubation, respectively. In all cases, less than 1% of protein was retained intracellularly. No differences were found in the uptake and transport of beta-lactoglobulin or albumin in the presence or absence of ligands. Furthermore, uptake and passage across Caco-2 monolayer of retinol or palmitic acid added either bound to beta-lactoglobulin or to albumin have been compared. The percentage of retinol found in the lower chamber was about 35% of the total retinol after 24 h of incubation for both proteins. However, the amount of retinol associated to cells was higher when it was added bound to beta-lactoglobulin than to albumin, about 26% and 10%, respectively. This fact suggests that the metabolic processing of retinol by Caco-2 cells is the rate-limiting step for retinol transport. The percentage of palmitic acid that crossed the monolayer was about 7%, remaining approx. 90% in the cells for beta-lactoglobulin and albumin. These data support the hypothesis that palmitic acid internalized by Caco-2 cells is mainly destined to serve the structural and energy needs. These results show evidence of retinol and palmitic uptake by Caco-2 cells when beta-lactoglobulin or albumin are the donors, and indicate that the type of binding protein does not affect the transport of both ligands through Caco-2 monolayer.

Fatal myocardial infarction in an 8-year-old girl with systemic lupus erythematosus, Raynaud's phenomenon, and secondary antiphospholipid antibody syndrome

An 8-year-old black girl with a 5 month history of systemic lupus erythematosus (SLE) and secondary antiphospholipid syndrome (APS) developed Raynaud's phenomenon, marked hemolytic anemia, and a fatal myocardial infarction (MI). Pathologic evaluation of the heart demonstrated a transmural acute MI associated with a recent thrombus of the circumflex coronary artery, thrombosis of small intramural arteries, and a coronary arteriopathy resembling fibromuscular dysplasia. Inflammatory or atherosclerotic changes of the coronary arteries were distinctly absent. This case represents the youngest reported patient with SLE, MI, and pathologic confirmation of nonatheromatous coronary artery disease. The observed coronary pathological findings may have accentuated the thrombogenic potential of the APS, resulting in coronary thrombosis. Cardiac lesions in SLE and APS are reviewed, and pathogenetic considerations for the coronary vasculopathy are discussed.

A three-hour measurement to evaluate bone calcium turnover

It is well established that short-term clearance of an intravenous calcium load in vivo reflects bone uptake. Using results from isotope-dilution experiments with 42Ca, a 3-h test has been developed to measure a quantity, gamma, related to bone accretion. This test is proposed as a useful, clinically applicable measure of bone status. For early times, t, after a bolus of 42Ca, plasma tracer dilution was well approximated by t-gamma, where gamma is related to the fractional rate of loss of tracer, q, from blood into bone (1/q)(dq/dt) = -gamma/t). Gamma was evaluated from kinetic measurements on 91 normal female children, adolescents, and adult women in the age range 4-50 years. For t < or = 3 h, all clearance curves were well fit by a power function. Gamma was found to vary from 0.244 +/- 0.031 for adult premenopausal women (N = 22) to 0.392 +/- 0.056 for prepubertal children (N = 29). Using the Spearman rank-order correlation test, gamma was correlated with bone accretion measured from classic calcium kinetic studies with a correlation coefficient of 0.721, significant at p < 0.005. In those cases in which accretion and resorption remain tightly linked, gamma also provides information on the state of calcium loss from bone. Gamma was evaluated in 14 subjects with bone disease characterised by increased resorption (osteoporosis, Paget's disease) and in 27 subjects with decreased accretion (osteogenesis imperfecta, types I, III, IV; steroid-treated juvenile dermatomyositis). All subjects with Paget's disease and with osteoporosis showed increased gamma, consistent with high bone turnover. The osteoporotic patients furthermore exhibited gamma increasing monotonically by approximately 1% per year after age 55.(ABSTRACT TRUNCATED AT 250 WORDS)

Mineral metabolism in children with dermatomyositis

OBJECTIVE

To measure calcium metabolism in 12 children with juvenile dermatomyositis (JDM).

METHODS

We used dual-tracer stable isotope studies to measure calcium metabolism in 12 children with JDM and a group of 43 healthy children (Group HC) of similar ages. Five of the JDM subjects were receiving steroids (Group JDM-ST) and 7 were not (Group JDM-NS).

RESULTS

The rate of calcium absorption in Group JDM-ST was lower than that in Group HC (19 +/- 10% vs 30 +/- 11%, p < 0.05). The lower rate of absorption was associated with a net loss of calcium each day (calculated calcium retention, Vbal, of -35 +/- 14 mg/day compared to +140 +/- 97 mg/day in Group HC, p < 0.01). Group JDM-NS showed slightly lower calcium absorption than Group HC and significantly lower Vbal (+33 +/- 70 mg/day, p < 0.01 vs Group HC) than Group HC. Group JDM-ST subjects also had decreased bone calcium deposition rates.

CONCLUSION

Patients with JDM may be at risk for significant loss of bone mineral associated with decreased calcium absorption, especially in the acute phase of their disease when they are receiving steroid therapy.

Pediatric rheumatic diseases

The rheumatic diseases of childhood are a relatively common and extraordinarily diverse group of illnesses; nevertheless, they are at least distantly related by similarities of immunodysregulation. These pathophysiologic relationships are reflected in affected children in similarities of historical, physical, and laboratory data as well as therapeutic intervention.

Effect of beta-lactoglobulin on the activity of pregastric lipase. A possible role for this protein in ruminant milk

The interaction of bovine beta-lactoglobulin with palmitic and oleic acids has been studied by a partition equilibrium method. Bovine beta-lactoglobulin displays only one high affinity binding site for fatty acids whose association constants for palmitic and oleic acids are 4.2 x 10(6) and 2.3 x 10(6) M-1, respectively. However, other binding sites with low affinity are also present. The existence of one high affinity binding site is in accordance with the amount of fatty acids naturally bound to beta-lactoglobulin isolated from milk. The effect of beta-lactoglobulin on ruminant pregastric lipases from a pharyngeal extract has been assayed. The activity of pharyngeal lipase on a triglyceride emulsion is increased about 200%, 250% and 190% in the presence of 10 mg/ml, 20 mg/ml and 40 mg/ml of beta-lactoglobulin, respectively, the last concentration representing that found physiologically in colostrum. Albumin, another ligand-binding protein, increases the activity of this enzyme to a lesser extent and high levels tend to inhibit enzyme action. These results indicate that beta-lactoglobulin could participate in the digestion of milk lipids during the neonatal period by enhancing the activity of pregastric lipase through removal of the fatty acids that inhibit this enzyme.

Insulin in bovine colostrum and milk: evolution throughout lactation and binding to caseins

The changes in insulin concentration in bovine milk in the first period of lactation and its association with other milk proteins were studied. Highest concentration was found in the first milking (327 ng/ml). This concentration fell within the first 24 h postpartum to about 50% of its initial value. By d 3, the level was about 25%, and, on d 7, a stable concentration was reached at approximately 46 ng/ml (about 14% of its initial value). This concentration is about 100 times higher than that in serum, which suggests a specific mechanism of transfer from blood to milk. Colostral whey obtained by ultrafiltration or ultracentrifugation contains much less insulin than colostrum. When colostrum or milk was incubated with [125I]insulin and whey and casein fractions were separated by precipitation, it was observed that most insulin remained with the casein. However, when colostrum was incubated with [125I]insulin and subjected to gel filtration, most of the radioactivity corresponded to free insulin, indicating that insulin is associated with the precipitated casein but not with the casein micelles in solution.

Negative inotropic effect induced by diethylamiloride (DEA) in rabbit myocardium

The effects of the Na+/H+ exchange blocking drug diethylamiloride (DEA) on mechanical function have been studied in the rabbit isolated, arterially perfused interventricular septum. At concentrations of 10(-6)-10(-5) M, DEA induced a significant, dose-dependent, negative inotropic effect (a 54% decrease from control values at the highest concentration), which was slow to develop. After a 45 min washout, recovery was almost complete (95 +/- 3.4%). At concentrations greater than 5 x 10(-5) M, DEA induced a rapid and marked decrease in developed tension, associated with a progressive decrease in excitability and incomplete recovery. Resting tension was not significantly modified at any of the concentrations tested. At greater than 10(-6) M DEA enhanced significantly the transient negative inotropic effect of the brief intracellular acidosis induced by removal of NH4Cl perfusion, both by decreasing the minimal value of developed tension and by increasing the time required to produce this effect. These effects suggest that the dose-dependent DEA negative inotropic effect could be mediated by a progressive intracellular acidosis produced by inhibition of the Na+/H+ exchange system.

Large-surface hemodialysis

A hemodialysis device with a surface of 5 m2, a blood flow (QB) of 500 ml/min, and a dialysate flow (QD) of 1,000 ml/min has enabled the authors to obtain in 6 h/week the same clearances for urea, creatinine, uric acid, phosphates, and vitamin B12 as has conventional hemodialysis (CH), which takes from 12 to 15 h/week. Twenty-five patients were hemodialyzed throughout 1 year with CH and another year with large-surface hemodialysis, 20 with a creatinine clearance (CCr) of 0.5 ml/min and 5 with a CCr between 0.5 and 4.5 ml/min. All followed a free diet and led a normal life. Hemodialysis time was 6 h/week, and the results obtained were equal to those of the previous year with a CH of 12 h/week. The use of a bicarbonate dialysate rich in glucose, with a relatively high level of potassium and sodium, can avoid the disequilibrium syndrome caused by quick hemodialysis and makes possible the removal of excess liquid in only 6 h/week, without disturbances for the patient.

[Parasitological survey, with special reference to schistosomiasis mansoni, conducted in the region of Jacupiranga (Ribeira valley, State of São Paulo). Survey of the location and distribution of planorbidian snails in the State of São Paulo. VII]

The results of a parasitological survey, emphasizing particularly schistosomiasis mansoni, are presented. The area under study was the district of Cajati, situated in the "município" of Jacupiranga (State of São Paulo, Brazil) near schistosomiasis-endemic areas in Vale do Ribeira. Though the presence of parasitized people by Schistosoma mansoni has been reported and focuses of Biomphalaria tenagophila, the species responsible for the spreading of the parasites through great areas of the state, has been localized, it has not been reported any autochthonous case nor the presence of schistosoma-infected planorbidian snails. As a contribution to the planorbidical chart of the State, it is reported as original the discovery of the species Drepanotrema cimex and D. depressissimum in that area. The detection of antitoxoplasmic antibodies in a sample of the studied population showed a significant prevalence rate corresponding to 76,4%.