The workplace and cardiovascular health: conclusions and thoughts for a future agenda

The evidence in this book provides convergent validation of a causal relationship between workplace stressors and CVD. Here, the editors explore new strategies for enhanced prevention and clinical management, work place interventions, and social policy to reduce the impact of CVD. These strategies acquire an urgent public health dimension, given the magnitude of the CVD epidemic and the current deterioration in conditions of working life.

Factors predictive of bone mineral density in eating-disordered women: a longitudinal study

OBJECTIVE

Osteoporosis in eating-disordered women is well established, but factors predictive of this condition have proved elusive. The roles of behavioral factors, weight, menstrual status, and the degree of bone mineral density change over the clinical course of the eating disorder were investigated

METHOD

A cohort of 56 eating-disordered women was subjected to bone mineral density measurement at Scan 1 and were followed up between 9 and 51 months later for repeat measurement (n = 10) at Scan 2.

RESULTS

High levels of reduced bone mineral density were observed. Total duration of amenorrhea, body mass index, frequency of vomiting, and cigarette and alcohol consumption accounted for 40% of the variance in spinal bone mineral density measurement at Scan 1. No significant changes in bone mineral density were observed at Scan 2 despite increases in body mass index.

DISCUSSION

The results suggest that increases in weight appear not to be sufficient to increase bone mineral density.

Taurine inhibition of metal-stimulated catecholamine oxidation

Taurine is an abundant amino acid found in mammalian tissues and it has been suggested to have cytoprotective functions. The aim of the present study was to determine if taurine had the potential to reduce oxidative stress associated with metal-stimulated catecholamine oxidation. Taurine and structural analogs of taurine were tested for their ability to inhibit metal-stimulated quinone formation from dopamine or L-dopa. Oxidative damage to proteins and lipids were also assessed in vitro and the effects of taurine were determined. Taurine (20 mM) was found to decrease significantly ferric iron (50-500 microM)- and manganese (10 microM)-stimulated L-dopa or dopamine oxidation. Taurine had no effect on zinc-induced dopamine oxidation and slightly potentiated copper- and NaIO(4)-stimulated quinone formation. Ferric iron-stimulated lipid peroxidation was not affected by taurine (1-20 mM). Protein carbonyl formation induced by ferric iron (500 microM) and L-dopa (500 microM) was significantly reduced by 10 mM taurine. The cytotoxicity of L-dopa (250 microM) and ferric chloride (75 microM) to LLC-PK(1) cells was attenuated by 10 mM taurine or hypotaurine. Homotaurine alone stimulated L-dopa oxidation and potentiated the cytotoxic effects of ferric iron. Homotaurine was found to be cytotoxic when combined with L-dopa or L-dopa/iron. In contrast, hypotaurine inhibited quinone formation and protected LLC-PK(1) cells. These studies suggest that taurine may exhibit cytoprotective effects against the oxidation products of catecholamines by acting as a scavenger for free radicals and cytotoxic quinones.

Bypass surgery for chronic lower limb ischaemia

BACKGROUND

Surgical bypass of an occluded arterial segment is the mainstay of treatment for patients with critical limb ischaemia. As with many surgical interventions, however, it was introduced without formal evaluation.

OBJECTIVES

The objective of this review was to determine the effects of bypass surgery in patients with chronic lower limb ischaemia.

SEARCH STRATEGY

The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, MEDLINE, EMBASE, reference lists of relevant articles, and contacted principal trial investigators.

SELECTION CRITERIA

All randomised controlled trials of bypass surgery versus control, or versus any other form of treatment.

DATA COLLECTION AND ANALYSIS

At least two reviewers extracted data and assessed trial quality independently. The reviewers contacted investigators to obtain information or data needed for the review that could not be found in published reports. Dichotomous data were analysed using the Peto odds ratio (OR), and continuous data with the weighted mean difference (fixed effect and random effects models).

MAIN RESULTS

Eight trials were identified which appeared to meet the inclusion criteria, but two were subsequently excluded. The remaining six trials involved a total of just over 700 patients, two trials comparing bypass surgery with angioplasty (PTA), and one with each of thromboendarterectomy, thrombolysis, exercise, and spinal cord stimulation. Four trials included patients with a range of disease severity (intermittent claudication and critical limb ischaemia), one was restricted to claudicants only and another to only critical limb ischaemia. The type of bypass procedure performed in each trial was similar: vein grafts for distal reconstructions; synthetic prostheses for aorto-iliac or ilio-femoral bypasses. The outcome measures varied, but four of the six trials included mortality and operative failure. In general the quality of the trials was good, but none was blinded because of the nature of the intervention. There were no clear differences between bypass surgery and PTA. Mortality and amputation rates did not differ significantly, although primary patency was significantly higher in the bypass group after 12 months (Peto OR 1. 6, 95% CI 1.0, 2.6) but not after four years (p=0.14). Compared with thrombolysis, amputation rates were significantly lower in the bypass group (Peto OR 0.2, 95% CI 0.1, 0.6), but mortality rates did not differ. Compared with thromboendarterectomy, restoration of blood flow was significantly greater in the bypass patients (Peto OR 9.2, 95% CI 1.7, 50.6), but mortality and amputation rates did not differ. Bypass did not differ significantly from exercise or spinal cord stimulation.

REVIEWER'S CONCLUSIONS

There is limited evidence for the effectiveness of bypass surgery and further large trials are required.

Robustness of protein folding kinetics to surface hydrophobic substitutions

We use both combinatorial and site-directed mutagenesis to explore the consequences of surface hydrophobic substitutions for the folding of two small single domain proteins, the src SH3 domain, and the IgG binding domain of Peptostreptococcal protein L. We find that in almost every case, destabilizing surface hydrophobic substitutions have much larger effects on the rate of unfolding than on the rate of folding, suggesting that nonnative hydrophobic interactions do not significantly interfere with the rate of core assembly.

Good manufacturing practice (GMP) compliance in the biologics sector: plasma fractionation

The U.S. blood supply is the safest it has ever been. Due to blood safety and the introduction of viral inactivation/clearance technologies, protein therapies derived from human blood have also in recent years had a history of product safety. Nevertheless, since 1995, the plasma-fractionation industry has experienced increased compliance-related actions by the Food and Drug Administration (FDA), as shown by a substantive increase in the number of FDA 483 inspectional observations, FDA warning letters and other FDA regulatory action. An evaluation of these trends shows that they reflect the implementation by the FDA of increased inspectional interest in the plasma-fractionation industry and an evolution of inspectional practices and standards of current good manufacturing practice (cGMP). Plasma fractionators have responded to FDA actions by carefully evaluating and addressing each inspectional observation, assessing impact to product and taking appropriate actions, including corrective actions to prevent future occurrence. They have made major investments in facilities, quality systems, personnel and training to meet the evolving standards of cGMP and in an effort to implement these standards systemically. Through industry associations, manufacturers have further enhanced product safety by adopting additional voluntary standards for plasma to prevent the entry of potentially unsuitable plasma into the production process. The industry remains committed to application of cGMP and to working with the FDA in further evolution of these standards while striving to assure a continued supply of safe, pure and effective plasma-derived therapies.

Structural transitions in the protein L denatured state ensemble

We use a broad array of biophysical methods to probe the extent of structure and time scale of structural transitions in the protein L denatured state ensemble. Measurement of amide proton exchange protection during the first several milliseconds following initiation of refolding in 0.4 M sodium sulfate revealed weak protection in the first beta-hairpin and helix. A tryptophan residue was introduced into the first beta-hairpin to probe the extent of structure formation in this part of the protein; the intrinsic fluorescence of this tryptophan was found to deviate from that expected given its local sequence context in 2-3 M guanidine, suggesting some partial ordering of this region in the unfolded state ensemble. To further probe this partial ordering, dansyl groups were introduced via cysteine residues at three sites in the protein. It was found that fluorescence energy transfer from the introduced tryptophan to the dansyl groups decreased dramatically upon unfolding. Stopped-flow fluorescence studies showed that the recovery of dansyl fluorescence upon refolding occurred on a submillisecond time scale. To probe the interactions responsible for the residual structure observed in the denatured state ensemble, the conformation of a peptide corresponding to the first beta-hairpin and helix of protein L was studied using circular dichroism spectroscopy and compared to that of full-length protein L and previously characterized peptides corresponding to the isolated helix and second beta-hairpin.

Experiment and theory highlight role of native state topology in SH3 folding

We use a combination of experiments, computer simulations and simple model calculations to characterize, first, the folding transition state ensemble of the src SH3 domain, and second, the features of the protein that determine its folding mechanism. Kinetic analysis of mutations at 52 of the 57 residues in the src SH3 domain revealed that the transition state ensemble is even more polarized than suspected earlier: no single alanine substitution in the N-terminal 15 residues or the C-terminal 9 residues has more than a two-fold effect on the folding rate, while such substitutions at 15 sites in the central three-stranded beta-sheet cause significant decreases in the folding rate. Molecular dynamics (MD) unfolding simulations and ab initio folding simulations on the src SH3 domain exhibit a hierarchy of folding similar to that observed in the experiments. The similarity in folding mechanism of different SH3 domains and the similar hierarchy of structure formation observed in the experiments and the simulations can be largely accounted for by a simple native state topology-based model of protein folding energy landscapes.

Satiation, capacity, and within-session responding

Responding may change substantially over the course of a session (McSweeney, Hinson, & Cannon, 1996). The role of satiation in this effect was investigated in three experiments. Experiment 1 showed that the capacity of pigeons to consume milo over a 1-hr period was relatively stable across three different methods of measurement. In Experiment 2, pigeons were divided into two groups that differed in their capacity based on one of those measures. Key pecking was then reinforced under a variable-interval 30-s schedule with hopper durations of 2 or 5 s. According to the satiation hypothesis, subjects with small capacities should satiate faster and therefore show greater decreases in food-reinforced responding than would subjects with larger capacities. The results confirmed this prediction and showed that the magnitudes of within-session decreases were better predicted by the amount an animal consumed relative to its capacity than by absolute amount alone. In Experiment 3, each pigeon was prefed 0, 5, 15, or 25 g of milo prior to each session. Consistent with the satiation hypothesis, increases in prefeeding produced lower overall response rates in the smaller capacity subjects than in the larger capacity subjects at each level of prefeeding. These experiments demonstrate the importance of a new variable in the control of behavior, and provide a recommended technique for its measurement.

CD44 is involved in selective leucocyte extravasation during inflammatory central nervous system disease

Clinical signs of experimental autoimmune encephalomyelitis (EAE) are associated with the selective recruitment of CD4+ memory (CD45RBlow CD44high) T cells into the central nervous system (CNS). However, we have found that many of these recently recruited memory cells are CD44low, suggesting that the CD44 antigen may be involved in, and transiently lost during, the extravasation process. Indeed, administration of a CD44-specific antibody (IM7.8.1) induced leucocyte CD44 shedding and both prevented the development and ameliorated the severity of established EAE by inhibiting mononuclear cell infiltration into the CNS. Trafficking of cells into lymph nodes, however, a property mainly of naïve cells, was essentially unaffected. In contrast, treatment with antibody to very late activation antigen-4 (VLA-4) prevented homing to both the CNS and to lymph nodes. This study contests previous reports that dismissed a role for CD44 in inflammation of the CNS and, coupled with observations in murine dermatitis and arthritis, suggests that CD44 is involved in the homing of primed lymphocytes to sites of inflammation. CD44 should therefore be considered a target for immunotherapy of T-cell-mediated inflammatory diseases, such as multiple sclerosis.

Ab initio protein structure prediction of CASP III targets using ROSETTA

To generate structures consistent with both the local and nonlocal interactions responsible for protein stability, 3 and 9 residue fragments of known structures with local sequences similar to the target sequence were assembled into complete tertiary structures using a Monte Carlo simulated annealing procedure (Simons et al., J Mol Biol 1997; 268:209-225). The scoring function used in the simulated annealing procedure consists of sequence-dependent terms representing hydrophobic burial and specific pair interactions such as electrostatics and disulfide bonding and sequence-independent terms representing hard sphere packing, alpha-helix and beta-strand packing, and the collection of beta-strands in beta-sheets (Simons et al., Proteins 1999;34:82-95). For each of 21 small, ab initio targets, 1,200 final structures were constructed, each the result of 100,000 attempted fragment substitutions. The five structures submitted for the CASP III experiment were chosen from the approximately 25 structures with the lowest scores in the broadest minima (assessed through the number of structural neighbors; Shortle et al., Proc Natl Acad Sci USA 1998;95:1158-1162). The results were encouraging: highlights of the predictions include a 99-residue segment for MarA with an rmsd of 6.4 A to the native structure, a 95-residue (full length) prediction for the EH2 domain of EPS15 with an rmsd of 6.0 A, a 75-residue segment of DNAB helicase with an rmsd of 4.7 A, and a 67-residue segment of ribosomal protein L30 with an rmsd of 3.8 A. These results suggest that ab initio methods may soon become useful for low-resolution structure prediction for proteins that lack a close homologue of known structure.

Differences between infants and adults in the social aetiology of wheeze. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood

OBJECTIVES

To compare the relation between relative deprivation, its associated social risk factors and the prevalence of wheeze in infancy and in adulthood.

DESIGN

A cross sectional population study.

SETTING

The three District Health Authorities of Bristol.

SUBJECTS

A random sample of 1954 women stratified by age and housing tenure to be representative of women with children < 1 in Great Britain and selected from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC).

MAIN OUTCOME MEASURES

The prevalence of wheeze for infants at six months after birth and for their mothers and fathers at eight months postpartum. Potential mediators of the relation between relative deprivation and wheeze measured were overcrowded living conditions, number of other siblings in the household, damp or mouldy housing conditions, maternal and paternal smoking behaviour, and infant feeding practice.

RESULTS

63.4% (1239) of the sample lived in owner occupied/mortgaged accommodation (relatively affluent) and 36.6% (715) lived in council house/rented accommodation (relatively deprived). Wheeze was significantly more likely for infants living in council house/rented accommodation (chi 2 = 15.93, df = 1, p < 0.0001), their mothers (chi 2 = 9.28, df = 1, p < 0.001) and their fathers (chi 2 = 7.41, df = 1, p < 0.01). For those living in council house/rented accommodation backward stepwise logistic regression analyses showed that infants with other siblings in the household were significantly more likely to wheeze (OR = 1.83, 95% CI = 1.27, 2.65), as were infants whose mothers smoked (OR = 1.82, 95% CI = 1.30, 2.55) and those who were breast fed for less than three months (OR = 0.66, 95% CI = 0.44, 0.98). Mothers with a partner who smoked were significantly more likely to report wheeze (OR = 1.73, 95% CI = 1.05, 2.85). There was no independent association between the social factors included in the analysis and the likelihood of wheeze for fathers.

CONCLUSIONS

This study identified differences in the social factors associated with a higher prevalence of wheeze in infancy and in adulthood; results suggested that this symptom was commonly linked to infection in infancy, but not in adulthood. While environmental tobacco smoke was associated with a higher prevalence of wheeze in infancy and in adulthood, this does not necessarily indicate a common underlying mechanism; possible explanations are discussed.

Prediction of protein-folding mechanisms from free-energy landscapes derived from native structures

Guided by recent experimental results suggesting that protein-folding rates and mechanisms are determined largely by native-state topology, we develop a simple model for protein folding free-energy landscapes based on native-state structures. The configurations considered by the model contain one or two contiguous stretches of residues ordered as in the native structure with all other residues completely disordered; the free energy of each configuration is the difference between the entropic cost of ordering the residues, which depends on the total number of residues ordered and the length of the loop between the two ordered segments, and the favorable attractive interactions, which are taken to be proportional to the total surface area buried by the ordered residues in the native structure. Folding kinetics are modeled by allowing only one residue to become ordered/disordered at a time, and a rigorous and exact method is used to identify free-energy maxima on the lowest free-energy paths connecting the fully disordered and fully ordered configurations. The distribution of structure in these free-energy maxima, which comprise the transition-state ensemble in the model, are reasonably consistent with experimental data on the folding transition state for five of seven proteins studied. Thus, the model appears to capture, at least in part, the basic physics underlying protein folding and the aspects of native-state topology that determine protein-folding mechanisms.

Rate of pull-out strength gain of dual-etched titanium implants: a comparative study in rabbits

The purpose of this study was to investigate the rate of pull-out strength gain of an etched titanium implant surface. Rabbit tibiae were used to compare machined titanium and proprietary dual-etched titanium implants. Two custom cylindric implants (3 mm in diameter and 4 mm in length) were placed in each right anteromedial tibia in 31 rabbits. At weeks 1, 2, 3, 4, 5, and 8, the implants in 5 rabbits were subjected to failure shear loading in a pull-out test. For shear failure testing, each tibial segment was mounted in a precision alignment jig, and an Instron pull-out test was performed on each implant. Beginning at week 3, there was a statistically significant difference (P < .01) between the dual-etched and the machined implants. There was a significant increase in strength for dual-etched implants between week 5 and week 8, while the machined implants did not show an increase during this time interval. The etched implants maintained a significantly greater pull-out strength for the remainder of the study, with a 3.2-fold greater mean strength at 8 weeks, equivalent to 6 months in humans. At 3 weeks, the etched implant's strength exceeded the strength that the machined implant had achieved at 8 weeks. In short-term healing in the rabbit tibia, the dual-etched surface demonstrated a more rapid rate of pull-out strength gain than the machined surface and remained significantly stronger throughout the 8 weeks of the study.

Hierarchy of structure loss in MD simulations of src SH3 domain unfolding

To complement experimental studies of the src SH3 domain folding, we studied 30 independent, high-temperature, molecular dynamics simulations of src SH3 domain unfolding. These trajectories were observed to differ widely from each other. Thus, rather than analyzing individual trajectories, we sought to identify the recurrent features of the high-temperature unfolding process. The conformations from all simulations were combined and then divided into groups based on the number of native contacts. Average occupancies of each side-chain hydrophobic contact and hydrogen bond in the protein were then determined. In the symmetric funnel limit, the occupancies of all contacts should decrease in concert with the loss in total number of native contacts. If there is a lack of symmetry or hierarchy to the unfolding process, the occupancies of some contacts should decrease more slowly, and others more rapidly. Despite the heterogeneity of the individual trajectories, the ensemble averaging revealed an order to the unfolding process: contacts between the N and C-terminal strands are the first to disappear, whereas contacts within the distal beta-hairpin and a hydrogen-bonding network involving the distal loop beta-turn and the diverging turn persist well after the majority of the native contacts are lost. This hierarchy of events resembles but is somewhat less pronounced than that observed in our experimental studies of the folding of src SH3 domain.

Graduated compression stockings in the prevention of venous thromboembolism

BACKGROUND

Surveys still show a wide variation in routine use of deep vein thrombosis (DVT) prophylaxis despite its established place in current patient management. This article reviews the mechanism of action, efficacy and complications of stockings in preventing DVT.

METHODS

Relevant publications indexed in Medline (1966-1998) and the Cochrane database were identified. Appropriate articles identified from the reference lists of the above searches were also selected and reviewed.

RESULTS AND CONCLUSION

Graduated compression stockings reduce the overall cross-sectional area of the limb, increase the linear velocity of venous flow, reduce venous wall distension and improve valvular function. Fifteen randomized controlled trials of graduated compression stockings alone were reviewed. Stockings reduced the relative risk of DVT by 64 per cent in general surgical patients and 57 per cent following total hip replacement. The effect of stockings was enhanced by combination with pharmacological agents such as heparin; the combination is recommended in patients at moderate or high risk of DVT. Knee-length stockings are as effective and should replace above-knee stockings. Complications are rare and avoidable.

Does employment improve the health of lone mothers? The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood

In Britain the government is currently proposing legislation that will encourage welfare recipients to gain employment. A central tenet of this 'welfare to work' policy is that employment will not only reduce the poverty of welfare recipients, but also improve their health. This research assessed the extent to which the movement from 'welfare to work' is likely to benefit the mental and physical health of lone mothers with preschool children. The sample was 719 lone mothers and a comparison group of 8779 women with partners drawn from the Avon Longitudinal Study of Pregnancy and Childhood (ALSPAC). Data collected by self completion questionnaire at 33 months postpartum provided information about average weekly take home family income and the mother's employment status. The health outcomes measured were general well being, both minor and major depression (using the Edinburgh Postnatal Depression Scale), self report of respiratory symptoms (cough/cold, wheeze, influenza) from 18-33 months postpartum and self report of symptoms common in the childbearing years (backache, haemorrhoids) also from 18-33 months postpartum. Lone mothers who were not employed were the poorest group in the sample; 94% of this group (402) had a family income of less than pound sterling 200 per week, compared with 72% (188) of lone mothers who were employed, 25% (905) of partnered women who were not employed and 12% (466) of partnered women who were employed. Lone mothers were significantly more likely than women with partners to report poorer well being (chi2 = 11.7, df = 3, P = 0.01), to have a major depressive disorder (chi2 = 92.6, df = 1, P = 0.0001) and to report wheeze (chi2 = 31.1, df = 1, P = 0.0001), but significantly less likely to report cough/cold (chi2 = 9.9, df = 1, P = 0.0001) or haemorrhoids (chi2 = 16.6, df = 1, P = 0.0001). Lone mothers who were unemployed and living on less than pound sterling 100 per week were significantly more likely to be depressed (chi2 = 3.9, df = 1, P = 0.05) than those who were employed and living on pound sterling 200 or more per week, and significantly less likely to report cough/cold (chi2 = 3.8, df = 1, P = 0.05). Logistic regression analyses showed no significant independent association between employment and better health for lone mothers. Rather, when compared with lone mothers who were not working, those who were employed were more likely to report minor respiratory symptoms such as cough/cold (OR = 1.51, 95% CI = 1.00,2.31). Overall, the results suggested that the movement from 'welfare to work' is unlikely to improve the health of lone mothers.

Chain collapse can occur concomitantly with the rate-limiting step in protein folding

We have directly characterized the extent of chain collapse early in the folding of protein L using time-resolved small angle X-ray scattering. We find that, immediately after the initiation of refolding, the protein exhibits dimensions indistinguishable from those observed under highly denaturing, equilibrium conditions and that this expanded initial state collapses with the same rate as that of the overall folding reaction. The observation that chain compaction need not significantly precede the rate-limiting step of folding demonstrates that rapid chain collapse is not an obligatory feature of protein folding reactions.

Dot immunobinding assay for detection of bovine herpesvirus 4 antibodies in rabbits

A dot immunobinding assay (DIA) was used for the detection of antibody against bovine herpesvirus 4 (BHV-4) in experimentally infected specific-pathogen-free male and female rabbits. A semipurified virus preparation was used as the antigen, and protein A/G-horseradish-peroxidase conjugate and diaminobenzidine tetrahydrochloride were used as the detection system. Results of the DIA procedure on serum samples of experimentally infected male and female rabbits were compared with those of a complement-dependent virus neutralization (VN) test. None of the tested sera (0/60 samples) from either male or female rabbits were positive by the complement-dependent VN test. Results of the DIA procedure for the same tested sera were positive in 35 of 60 samples (58%) from BHV-4 infected rabbits, indicating higher sensitivity of DIA procedure as compared with the complement-dependent VN test.

Matching theory and experiment in protein folding

There has been considerable progress made over the past year in linking experimental and theoretical approaches to protein folding. Recent results from several independent lines of investigation suggest that protein folding mechanisms and landscapes are largely determined by the topology of the native state and are relatively insensitive to details of the interatomic interactions. This dependence on low-resolution structural features, rather than high-resolution detail, suggests that it should be possible to describe the fundamental physics of the folding process using relatively low-resolution models. Recent experiments have set benchmarks for testing new models and progress has been made in developing theoretical models for interpreting and predicting experimental results.

Results of the National Cooperative Inner-City Asthma Study (NCICAS) environmental intervention to reduce cockroach allergen exposure in inner-city homes

BACKGROUND

Cockroach allergen is important in asthma. Practical methods to reduce exposure are needed.

OBJECTIVE

We sought to evaluate the effectiveness of house cleaning and professional extermination on lowering cockroach antigen levels in inner-city dwellings.

METHODS

As part of the National Cooperative Inner-City Asthma Study intervention, 265 of 331 families with asthmatic children who had positive skin test responses to cockroach allergen consented to a professional home extermination with 2 applications of a cockroach insecticide (Abamectin, Avert) combined with directed education on cockroach allergen removal. On a random subset of 48 homes undergoing cockroach extermination in the intervention group, Bla g 1 was measured in settled dust from the kitchen, bedroom, and TV/living room. The first sample was collected 1 week before extermination, with additional samples after the exterminations at approximately 2, 6, and 12 months after the first sample. Self-reported problems with cockroaches were collected at baseline and after 12 months of follow-up in both the intervention and control group.

RESULTS

The geometric mean kitchen level of Bla g 1 decreased at 2 months (33.6 U/g) relative to preextermination levels (68.7 U/g, P <.05). The percent of kitchens with over 8 U/g of Bla g 1 followed a similar pattern, but only the decrease from preextermination to 6-month levels was significant (86.8% vs 64.3%, P <.05). By the 12-month visit, the allergen burden had returned to or exceeded baseline levels. Except for an increase in the bedroom at 2 months (8.9 U/g vs 11.1 U/g, P <.05), no other significant change was seen. Only about 50% of the families followed the cleaning instructions; no greater effect was found in these homes. Self-reported problems with cockroaches showed no difference between the intervention and control group after 1 year of follow-up.

CONCLUSIONS

Despite a significant, but short-lived, decrease the cockroach allergen burden remained well above levels previously found to be clinically significant.

Algorithm for nutritional support: experience of the Metabolic and Infusion Support Service of St. Jude Children's Research Hospital

The Metabolic and Infusion Support Service (MISS) at St. Jude Children's Research Hospital was established in 1988 to improve the quality of nutritional support given to children undergoing therapy for cancer. This multidisciplinary group, representing each of the clinical services within the hospital, provides a range of services to all patients requiring full enteral or parenteral nutritional support. In 1991, the MISS developed an algorithm for nutritional support which emphasized a demand for a compelling rationale for choosing parenteral over enteral support in patients with functional gastrointestinal tracts. Compliance with the algorithm was monitored annually for 3 years, with full compliance defined as meeting all criteria for initiating support and selection of an appropriate type of support. Compliance rates were 93% in 1992, 95% in 1993 and 100% in 1994. The algorithm was revised in 1994 to include criteria for offering oral supplementation to patients whose body weight was at least 90% of their ideal weight and whose protein stores were considered adequate. Full support was begun if no weight gain occurred. Patients likely to tolerate and absorb food from the gastrointestinal tract were classified into groups defined by the absence of intractable vomiting, severe diarrhea, graft-vs.-host disease affecting the gut, radiation enteritis, strictures, ileus, mucositis and treatment with allogeneic bone marrow transplant. Overall, the adoption of the algorithm has increased the frequency of enteral nutritional support, particularly via gastrostomies, by at least 3-fold. Our current emphasis is to define the time points in therapy at which nutritional intervention is most warranted.