Recovery of an urbanised estuary: Clean-up, de-industrialisation and restoration of redundant dock-basins in the Mersey

For much of the 20th century, the Mersey in North West England was one of the worst polluted estuaries in Europe. Water from a range of polluting industries plus domestic sewage was discharged into the Mersey Catchment and Estuary. Recovery came through a concerted clean-up campaign and tightening environmental regulations, partly driven by European Commission Directives, coupled with de-industrialisation from the 1970s onward. Recovery of oxygen levels in the Estuary led to the return of a productive ecosystem. This led to conservation designations, but also concerns about transfer of pollutants to higher trophic levels in fish, birds and humans. As part of urban renewal, ecosystems in disused dock basins were restored using mussel biofiltration and artificial de-stratification, facilitating commercial redevelopment and creation of a tourist destination. The degradation and recovery of the Mersey from peak-pollution in the mid-20th century is put in the context of wider environmental change and briefly compared to other systems to develop a hysteresis model of degradation and recovery, often to novel ecosystems.

PRL3 enhances T-cell acute lymphoblastic leukemia growth through suppressing T-cell signaling pathways and apoptosis

T cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy of thymocytes and is largely driven by the NOTCH/MYC pathway. Yet, additional oncogenic drivers are required for transformation. Here, we identify protein tyrosine phosphatase type 4 A3 (PRL3) as a collaborating oncogenic driver in T-ALL. PRL3 is expressed in a large fraction of primary human T-ALLs and is commonly co-amplified with MYC. PRL3 also synergized with MYC to initiate early-onset ALL in transgenic zebrafish and was required for human T-ALL growth and maintenance. Mass spectrometry phosphoproteomic analysis and mechanistic studies uncovered that PRL3 suppresses downstream T cell phosphorylation signaling pathways, including those modulated by VAV1, and subsequently suppresses apoptosis in leukemia cells. Taken together, our studies have identified new roles for PRL3 as a collaborating oncogenic driver in human T-ALL and suggest that therapeutic targeting of the PRL3 phosphatase will likely be a useful treatment strategy for T-ALL.

Communication: Fragment-based Hamiltonian model of electronic charge-excitation gaps and gap closure

Capturing key electronic properties such as charge excitation gaps within models at or above the atomic scale presents an ongoing challenge to understanding molecular, nanoscale, and condensed phase systems. One strategy is to describe the system in terms of properties of interacting material fragments, but it is unclear how to accomplish this for charge-excitation and charge-transfer phenomena. Hamiltonian models such as the Hubbard model provide formal frameworks for analyzing gap properties but are couched purely in terms of states of electrons, rather than the states of the fragments at the scale of interest. The recently introduced Fragment Hamiltonian (FH) model uses fragments in different charge states as its building blocks, enabling a uniform, quantum-mechanical treatment that captures the charge-excitation gap. These gaps are preserved in terms of inter-fragment charge-transfer hopping integrals T and on-fragment parameters U((FH)). The FH model generalizes the standard Hubbard model (a single intra-band hopping integral t and on-site repulsion U) from quantum states for electrons to quantum states for fragments. We demonstrate that even for simple two-fragment and multi-fragment systems, gap closure is enabled once T exceeds the threshold set by U((FH)), thus providing new insight into the nature of metal-insulator transitions. This result is in contrast to the standard Hubbard model for 1d rings, for which Lieb and Wu proved that gap closure was impossible, regardless of the choices for t and U.

Non-trisomic homeobox gene expression during craniofacial development in the Ts65Dn mouse model of Down syndrome

Trisomy 21 in humans causes cognitive impairment, craniofacial dysmorphology, and heart defects collectively referred to as Down syndrome. Yet, the pathophysiology of these phenotypes is not well understood. Craniofacial alterations may lead to complications in breathing, eating, and communication. Ts65Dn mice exhibit craniofacial alterations that model Down syndrome including a small mandible. We show that Ts65Dn embryos at 13.5 days gestation (E13.5) have a smaller mandibular precursor but a normal sized tongue as compared to euploid embryos, suggesting a relative instead of actual macroglossia originates during development. Neurological tissues were also altered in E13.5 trisomic embryos. Our array analysis found 155 differentially expressed non-trisomic genes in the trisomic E13.5 mandible, including 20 genes containing a homeobox DNA binding domain. Additionally, Sox9, important in skeletal formation and cell proliferation, was upregulated in Ts65Dn mandible precursors. Our results suggest trisomy causes altered expression of non-trisomic genes in development leading to structural changes associated with DS. Identification of genetic pathways disrupted by trisomy is an important step in proposing rational therapies at relevant time points to ameliorate craniofacial abnormalities in DS and other congenital disorders.

Low urinary iodine postpartum is associated with hypothyroid postpartum thyroid dysfunction and predicts long-term hypothyroidism

BACKGROUND

Postpartum thyroid dysfunction (PPTD) is characterized by an early hyperthyroid phase followed, with peak prevalence at 6 months, by a hypothyroid phase which carries a risk of long-term hypothyroidism. Iodine has a major effect on thyroid function. Western Australia has previously been shown to be iodine replete.

OBJECTIVE

To examine the iodine status of women with and without PPTD and the relationship of iodine status postpartum with long-term hypothyroidism.

DESIGN

Case-control with follow-up.

PATIENTS

A total of 149 women at 6 months postpartum (74 PPTD, 75 controls) with 98 (46 PPTD, 52 controls) followed up at 12 years.

MEASUREMENTS

Urinary iodine concentration (UIC) and thyroid function at 6 months postpartum; thyroid function at 12-year follow-up.

RESULTS

At 6 months postpartum, median UIC (quartiles) for observed TSH ranges were: for TSH < 0·4 mU/l 130·0 μg/l (82·0, 170·0); for TSH 0·4-4·0 mU/l 123·0 μg/l (80·5, 168·0); for TSH > 4·0 mU/l 85·0 μg/l (40·0, 141·5), P = 0·018. The odds ratio (OR) of hypothyroid PPTD with each unit of decreasing log iodine was 2·54, (95%CI: 1·47, 4·35), and with UIC < 50 μg/l, OR 4·22, (95%CI: 1·54, 11·55). In the long term, decreased log UIC significantly predicted hypothyroidism at 12-year follow-up (P = 0·002); as did UIC < 100 μg/l (P = 0·03) and UIC < 50 μg/l (P = 0·02). The association was independent of antibody status.

CONCLUSION

Low UIC measured at 6 months postpartum is associated with hypothyroid PPTD and independently predicts long-term hypothyroidism. We believe that it results from more severe preceding destructive thyroiditis, with discharge of thyroidal iodine, and thereby predicts a greater risk of long-term hypothyroidism.

Granulomatous enteritis in a thoroughbred horse

A case of granulomatous enteritis in a three-year-old thoroughbred horse is described. Onset of clinical signs succeeded pyrexia of unknown aetiology. The horse was emaciated, depressed and inappetent but diarrhoea was not a feature of the condition. There was hypoproteinaemia, anaemia, leucopaenia and abnormal small-intestinal carbohydrate absorption. Rectal biopsy revealed granulomatous changes in the rectal mucosa. As a result of these findings, euthanasia was performed and an autopsy was carried out. Histopathology showed marked villous atrophy in the small intestine with a diffuse mononuclear cellular infiltration involving mainly the submucosa and lamina propria. There were occasional granulomatous foci. The mononuclear cells consisted mainly of lymphocytes and histiocytes. No aetiological agent was isolated.

DETERMINATION OF THE VOLUME OF THE EXTRACELLULAR FLUID OF THE BODY WITH RADIOACTIVE SODIUM

A method for measuring the volume of fluid available for the distribution of sodium (sodium space) by the use of its radioactive isotope (Na²⁴) has been described and the accuracy of the method has been discussed. Simultaneous determinations of the plasma volume by means of the blue dye T-1824 and the volume of the extracellular fluid by employing radiosodium and sodium thiocyanate have been made in normal subjects. Repeated measurements were made at varying periods of time in the same individuals. In order to establish the rate of diffusion equilibrium for the radioactive isotope of sodium and thiocyanate between serum and serous effusions, simultaneous samples of both were obtained at varying intervals after the intravenous injection of these substances. Since evidence in the literature indicates that there is an excess of sodium mainly limited to bone, which cannot be attributed to the extracellular phase, experiments on dogs and man were so devised that the ratio of tissue concentration to plasma concentration for radiosodium and chemically determined chloride could be calculated. The following conclusions may be drawn from the results of this investigation: 1. Radiosodium after intravenous administration spreads rapidly during the first 3 hours from the plasma into a volume of fluid which represents approximately 25 per cent of the body weight of man. Thereafter for 6 hours it diffuses more slowly into certain tissue spaces—the central nervous system and probably the skeleton. The plasma volume and interstitial fluid represent 15 and 85 per cent of the sodium space respectively. 2. Diffusion equilibrium for both radiosodium and thiocyanate is not established between serum and transudates in edematous patients until from 9 to 12 hours after the intravenous injection of these substances. 3. Until more complete information is available, it is concluded that unless the difference between repeated observations on the same individual exceeds ±1.38 liters there is no significant change in the sodium space providing that the activity of the standard and serum samples are in the range of 40 counts per minute per milliliter with the counting apparatus used. As the activity of the samples increases, the error becomes less because there is no correlation between the magnitude of the error and the magnitude of the activity. 4. Climatic conditions produce no significant changes in the volume of the blood or extracellular fluid. 5. In the dog, following the intravenous injection of radiosodium, the concentration of the isotope in bone reaches its maximum rapidly (3 hours). The extra sodium in the skeleton of dog is equal to about ¼ of the total counts in the body, assuming that the chloride space of bone represents its extracellular volume. Similar amounts of excess sodium are found in the skeleton of man 12 hours after the administration of Na²⁴. 6. Correction of the sodium space of man for the excess sodium reduced the average value by 3.7 liters or 18.9 per cent. The average corrected volume for the normal subjects 6 hours after the injection is 15.9 liters or 21.1 per cent of the body weight compared with the thiocyanate space of 17.7 liters, representing 23.5 per cent of the body weight. 7. The most useful method for calculating the sodium space from the data obtained after intravenous administration of radiosodium is as follows: See PDF for Equation This space exceeds the volume of extracellular fluid by the amount of excess sodium in the body that cannot be attributed to the extracellular phase. 8. While neither the thiocyanate method nor the radiosodium method gives precise estimates of the extracellular fluid, the error is of the same order of magnitude in both. For clinical use, the thiocyanate method is superior because of the ready availability of the substance, and the apparatus required.

Many-body dipole-dipole interactions between excited Rb atoms probed by wave packets and parametric four-wave mixing

Dipole-dipole interactions between excited Rb atoms at long range (approximately 300a0-2150a0) have been observed with molecular wave packets and a coherent nonlinear optical process. Fourier analysis of the parametric four-wave mixing (PFWM) signal wave intensity produced in femtosecond pump-probe experiments demonstrates the appearance of sidebands associated with the Rb 7s-5d(5/2) quantum beating frequency of approximately 18.3 THz. Calculations show that the observed sideband splittings and Fourier domain profiles result from multiple atom, dipole-dipole interactions, and ensembles comprising five or fewer Rb (7s, 6p) atoms account for virtually all of the data.

Resting energy expenditure in females with cystic fibrosis: Is it affected by puberty?

OBJECTIVE

The aims of this study were to determine the effect of puberty and the menstrual cycle on resting energy expenditure (REE) in females with cystic fibrosis (CF).

DESIGN

Cross-sectional study. All participants had measurements of REE, anthropometry and pubertal staging. The measurements in the postmenarche group were carried out both in the follicular and luteal phases of their menstrual cycle.

SETTING

CF outpatient clinic at the Children's Hospital at Westmead.

SUBJECTS

Fifty-six females with CF and pancreatic insufficiency (13 postmenarche) were recruited from the hospital clinic and 63 controls (21 postmenarche) were recruited through families and friends of hospital staff.

RESULTS

Females with CF had a higher REE than controls (111.6+/-12.8% of predicted from controls P<0.001). There was a significant effect of menarche on REE with a decrease in the postmenarche -470 kJ/24 h compared with premenarche after adjustment for fat-free mass, fat mass and group (control or CF). There was no difference in REE between the follicular and luteal phases for either CF or controls.

CONCLUSIONS

Females with CF had raised REE that appeared to be independent of menarche. This study implies all females with CF and pancreatic insufficiency may need more intensive dietary management, owing to raised REE, to maintain growth and nutritional status, and possibly improve survival.

Iron status of young Vietnamese children in Australia

OBJECTIVE

The aim of this study was to estimate the prevalence of iron deficiency in Vietnamese children living in Australia and to identify risk factors associated with iron deficiency.

METHODS

A cohort of healthy term Vietnamese infants, were followed from birth (n = 210) to 18 months (n = 174) with anthropometry, dietary intake and feeding practices measured at seven time points. Socio-demographic data were collected from the parents at the first home visit. At 18 months iron status was examined by full blood count and plasma ferritin concentration in 129/152 (85%) of the eligible children. Iron depletion was defined as a plasma ferritin level < 10 microg/L. Iron deficiency without anaemia was defined as iron depletion plus MCV < 70fl and iron deficiency anaemia was defined as iron deficiency anaemia plus Hb < 110 g/L.

RESULTS

The prevalence of iron deficiency was iron depletion 19.4% (95% CI: 13.0%, 27.3%), iron deficiency without anaemia 3.1% (95% CI: 0.9%, 7.8%) and iron deficiency anaemia 3.9% (95% CI: 1.3%, 8.8%). Multiple regression analysis showed three significant predictors of iron deficiency: cows milk intake (negative effect), meat, fish or poultry intake (positive effect) and weight gain (negative effect). A cows milk intake > or = 650 mL/day was a risk factor for iron deficiency.

CONCLUSION

Prevalence of iron deficiency at 18 months was high despite appropriate infant feeding practices during the first year. Modification of the diet in the second year of life may decrease the risk of iron deficiency in Vietnamese children.

Outcomes of a nutrition audit in a tertiary paediatric hospital: implications for service improvement

OBJECTIVE

To examine the process of anthropometric assessment of nutritional status in a tertiary paediatric hospital, to identify the barriers and to make recommendations for service improvement.

METHODS

The accuracy of height and weight scales in wards was checked. Dietitians measured height and weight of a representative sample of 245 inpatients and checked whether these measurements had been recorded on bed charts. Patients were classified as overweight, obese or under-nourished. Diagnoses and procedures were obtained for each patient. Funding implications were modelled for inappropriate coding of nutritional status.

RESULTS

The barriers to nutritional assessment and management of nutritional comorbidities were: (i) inaccurate height scales in seven out of 12 wards; (ii) under-recording of height and weight on patient bed charts (73% height missing, 12% both height and weight missing); (iii) under-reporting of obesity and under-nutrition in medical notes (one of eight obese patients, and none of 28 undernourished patients, reported); and (iv) low referral rate of obese or under-nourished children to dietetic services (two of 42 overweight/obese patients referred, five of 28 undernourished patients referred). Funding simulation showed that if under-nourished patients were correctly diagnosed then the potential facility reimbursement would have increased by $A52 326.

CONCLUSIONS

Barriers to nutritional assessment can lead to failure to diagnose and treat both over- and under-nutrition, thereby affecting quality of patient care, and may have financial implications for hospitals. Suggestions for service improvement include provision of accurate equipment, adequate training of staff undertaking nutritional assessments and clear definitions of staff responsibilities in all aspects of the process.

Obesity and under-nutrition in a tertiary paediatric hospital

OBJECTIVE

(i) To determine the prevalence of over- and under-nutrition in both inpatients and outpatients in a tertiary paediatric hospital; (ii) to compare the prevalence of over-nutrition with that in the Australian community and (iii) to determine whether nutritional status has an impact on length of stay in hospital.

METHODS

Patients aged over 12 months were proportionately sampled from medical and surgical wards and outpatient clinics. Data were collected for 245 inpatients (54% male) and 272 outpatients (55% male). Children's height, weight and body mass index (kg/m2) were measured. Overweight, obesity and under-nutrition were defined according to international criteria. Prevalence of overweight and obesity was compared with that in the 1995 Australian National Nutrition Survey (NNS).

RESULTS

Similar proportions of inpatients and outpatients were underweight (6%) and wasted (4%). The prevalence of overweight and obesity in inpatients (22%) was similar to the NNS but was significantly higher in outpatients (32%, P < 0.0001). In a regression model to predict inpatient length of stay, nutritional status (P = 0.004) and the interaction between age and nutritional status (P = 0.009) were significant predictors. For over-nourished inpatients, length of stay increased significantly with age. For normally nourished and under-nourished inpatients, length of stay was relatively constant, regardless of age.

CONCLUSIONS

There is a high prevalence of over-nutrition in paediatric patients, and increased length of stay for older over-nourished inpatients. These issues need to be addressed in terms of opportunities for intervention and impact on hospital resources.

Growth and feeding practices of Vietnamese infants in Australia

OBJECTIVE

To investigate the growth and feeding practices in first-generation Vietnamese infants living in Australia.

DESIGN

Cohort study.

SETTING

The study was conducted between 1999 and 2002 in Sydney.

SUBJECTS

A total of 239 Vietnamese women were recruited randomly from antenatal clinics, and of these 210 were initially seen. During the first year, 20 cases (9.5%) were lost to follow-up. Data were collected at 0.5, 2, 4, 6, 9 and 12 months.

RESULTS

Vietnamese infants were significantly longer and heavier than reference data (both P<0.0001). The Vietnamese infants had a significant decline in weight growth with age compared with reference data (P<0.001). The Vietnamese infants had marginally higher s.d. score for ideal weight for length than reference data (P=0.044). There was a significant decline in ideal weight for length with age compared with reference data (P=0.0065). Both parents were significantly shorter (mean s.d. height scores: -1.5+/-0.8 (mother) and -1.8+/-0.8 (father)) than reference data (P<0.001). The incidence of breast feeding was 79%, but half of the breast feeding women had stopped breast feeding by 3 months. A total of 162 (79.8%) infants were given infant formula within the first week, of whom 131 (80.1%) were fed infant formula within the first 24 h after birth.

CONCLUSIONS

Vietnamese infants in this study had growth comparable with reference data despite their parents being shorter than reference data. Breast feeding duration was short with infant formula being introduced early.

In vivo proton (H1) magnetic resonance spectroscopy for cervical carcinoma

Proton magnetic resonance spectroscopy (MRS) may be a useful tool in both the initial diagnosis of cervical carcinoma and the subsequent surveillance after radiation therapy, particularly when other standard diagnostic methods are inconclusive. Single voxel magnetic resonance (MR) spectral data were acquired from 8 normal volunteers, 16 patients with cervical cancer before radiation therapy, and 18 patients with cervical cancer after radiation therapy using an external pelvic coil at a 1.5-T on a Signa system. The presence or absence of various resonances within each spectrum was evaluated for similarities within each patient group and for spectral differences between groups. Resonances corresponding to lipid and creatine dominated the spectrum for the eight normal volunteers without detection of a choline resonance. Spectra from 16 pretreatment patients with biopsy-proven cervical cancer revealed strong resonances at a chemical shift of 3.25 ppm corresponding to choline. Data acquired from the 18 posttreatment setting studies was variable, but often correlated well with the clinical findings. Biopsy confirmation was obtained in seven patients. H1 MRS of the cervix using a noninvasive pelvic coil consistently demonstrates reproducible spectral differences between normal and neoplastic cervical tissue in vivo. However, signal is still poor for minimal disease recurrence. Further study is needed at intervals before, during, and after definitive irradiation with biopsy confirmation to validate the accuracy of MRS in distinguishing persistence or recurrence of disease from necrosis and fibrosis.

Variations in the measurement of resting energy expenditure in children with cystic fibrosis

OBJECTIVE

To investigate in children with cystic fibrosis (CF) and children without CF: (1) the test-retest reproducibility of a 20 min resting energy expenditure (REE) measurement; and (2) the long-term reproducibility of REE measurements in children with CF using longitudinal data.

DESIGN

Cross-sectional study and longitudinal cohort.

SETTING

A tertiary referral paediatric hospital.

SUBJECTS

A total of 31 (11 male, 20 female) children (aged 12.8+/-3.6 y) with CF and 32 (14 male, 18 female) healthy children without CF (aged 12.2+/-2.3 y) were enrolled in the short-term reproducibility study. Long-term REE measurement reproducibility was assessed in another 14 children (5 male, 9 female) with CF, comparing their initial REE measurement with a subsequent measurement 1-2 y later.

METHODS

All children had measurements of height, weight, skinfold thickness and indirect calorimetry.

RESULTS

There was no statistically significant difference in REE between repeated measurements in children with CF (mean+/-s.d., 6240+/-1280 and 6220+/-1315 kJ/24 h) and in the children without CF (6040+/-956 and 6015+/-943 kJ/24 h). For the children with CF, the intraclass correlation coefficient was 0.99 and for children without CF the intraclass correlation coefficient was 0.97. The measurement errors were 119 and 177 kJ, respectively. Approximately 80% of the variation in REE in the CF group and 70% in the group without CF was explained by fat-free mass (FFM). Analysis of the longitudinal CF data show there was no difference in REE between a child's first measurement (5140+/-1140 kJ) and their subsequent measurement (5460+/-1190 kJ), after adjustment for changes in body size between the measurements.

CONCLUSION

This study has demonstrated that a short-term 20 min REE measurement is reproducible and therefore valid in children with CF and children without CF. These results also indicate that in children with CF, long-term REE measurements are reproducible.

Isolation of the components of a complex mixture by means of column switching for their enhanced detection by mass spectrometry

Mass spectral characterization of low-level impurities in drug substances and formulations may be challenging when using a validated HPLC method developed for optimal chromatographic performance. In many cases, either the mobile phase contains non-volatile additives that are deleterious to the operation of the mass spectrometer, or some of the related substances fail to ionize effectively under electrospray ionization or atmospheric pressure chemical ionization conditions. This paper describes a way to capture these low-level compounds from an analytical HPLC column using a small trapping column. Mixture components are retained on the trapping column by means of reducing the solvent strength of the eluent. Subsequent elution of trapped compounds using mobile phases more amenable to mass spectral analysis yields improved detection and characterization of low-level compounds of interest. Possible applications of peak trapping and elution include: (1) analysis of compounds separated using a mobile phase containing high concentrations of non-volatile additives, (2) analysis of organic acids separated using a low-pH mobile phase (containing trifluoroacetic acid), and (3) improving the detection limit of a low-level compound of interest through multiple collections. The peak trapping apparatus and optimization experiments are described.

Pursuit of optimal carbohydrate-based anticancer vaccines: preparation of a multiantigenic unimolecular glycopeptide containing the Tn, MBr1, and Lewis(y) antigens

A novel preparation of nonnatural glycoamino acids starting from n-pentenyl glycosides is described. The approach involves a Horner-Emmons olefination with a suitably protected glycine-derived phosphonate, followed by catalytic asymmetric hydrogenation, which proceeds with excellent diastereomeric selectivity. The synthetic methodology was useful for the preparation of glycoamino acids containing the Tn antigen, the MBr1 antigen (Globo-H), the Le(y) antigen, and lactose. These glycoamino acids can also serve as units for peptide synthesis. The synthesis of polyvalent glycopeptides containing three different antitumor antigens is described (28 and 29), and these have been prepared for conjugation to carrier protein in order to access the immunogenicity for tumor immunotherapy applications.

The biochemical and clinical course of postpartum thyroid dysfunction: the treatment decision

OBJECTIVE

To follow the clinical and biochemical course of a cohort of women who had postpartum thyroid dysfunction (PPTD) at 6 months postpartum and to examine the treatment practices of general practitioners and endocrinologists in the setting of PPTD.

DESIGN

Prospective longitudinal study.

SETTING

Metropolitan, Perth, Australia.

PARTICIPANTS

Eighty-six Caucasian women who were identified to have PPTD at 6 months postpartum in a cross-sectional study of 748 women.

MAIN OUTCOME MEASURES

Characteristics of the clinical and biochemical course of PPTD and documentation of the treatment practices and factors influencing treatment of PPTD by general practitioners and endocrinologists.

RESULTS

Sixteen of 86 women (19%) were receiving treatment at 9 months postpartum and by 30 months postpartum 27% of women had received treatment for PPTD. Fifty-one percent of those not treated were biochemically euthyroid at 9 months, although, for those with hypothyroid biochemistry at 6 months, the median TSH at 18 months was at the upper limit of the reference range. Thyroid peroxidase antibody titre fell over the 2 years of follow-up. There was no significant change in clinical parameters over the study. Forty-nine percent of endocrinologists and 73% of general practitioners reported that they required clinical signs or symptoms before initiating treatment for hypothyroid PPTD.

CONCLUSIONS

In a cohort of women with postpartum thyroid dysfunction, a quarter received treatment. Elevated TSH in untreated women does not completely return to the normal median. The role of clinical assessment in treatment decision-making differs between primary care physicians and endocrinologists. A case is made for the early Institution of permanent thyroxine replacement in women with postpartum thyroid dysfunction, elevated TSH and positive thyroid antibodies.

Incidence of peritonitis in chronic peritoneal dialysis patients infused with intravenous iron dextran

BACKGROUND

The Dialysis Outcomes Quality Initiative (DOQI) guidelines, published in 1997, emphasize the need for careful monitoring of iron stores and for provision of adequate iron replacement therapy to achieve target goals of hemoglobin concentration in end-stage renal disease (ESRD) patients, especially those treated with recombinant erythropoietin (rHuEPO). Intravenous iron dextran (IVID) therapy, which has long been used in hemodialysis patients, is increasingly being used in chronic peritoneal dialysis (CPD) patients. In 1997, we began using this form of iron therapy for our CPD patients. However, because considerable data exists to show a relationship between iron metabolism and acute infections, we questioned whether IVID infusion placed our patients at greater risk for peritonitis, the leading cause of death and patient drop-out from CPD therapy.

OBJECTIVE

To evaluate the relationship between iron and infection, we studied episodes of peritonitis in CPD patients who were infused with IVID.

DESIGN

In a retrospective study of adult CPD patients who received IVID during 1998, we investigated the occurrence of peritonitis episodes and the spectrum of causative organisms. Patients with a hemoglobin level of < 12.5 g/dL who also had a ferritin level < 100 ng/mL or a transferrin saturation level < 20% (or both) and who did not respond to oral iron therapy, were administered between 0.5 g and 1.0 g of IVID in an outpatient hospital setting. We calculated the expected and observed number of peritonitis episodes in these patients within 30, 60, and 90 days after infusion of IVID.

RESULTS

During the study period, 56 patients received 77 doses of IVID, with 14 patients requiring 2 or more infusions. Of the 77 doses, 71 were given as a 1-g bolus. The IVID was well tolerated by all patients. Within 90 days of IVID administration, 14 patients developed peritonitis: 6 episodes occurred within 30 days, 7 episodes occurred between 31 and 60 days, and 1 episode occurred between 61 and 90 days after the IVID dosing. The peritonitis rate for patients not receiving IVID was 1 episode per 13.7 patient-months. Taking this rate as the "expected" rate, the expected number of episodes of peritonitis for the study population was 5.6 episodes within 30 days, 11.2 episodes within 60 days, and 16.8 episodes within 90 days following IVID administration. The difference between the expected and observed rates of peritonitis in patients who were dosed with IVID was not statistically different. The spectrum of organisms seen in the peritonitis episodes in the study population was not significantly different from that seen in the peritonitis episodes in our CPD unit population.

CONCLUSIONS

There is evidence that IVID infusion therapy can improve anemia and reduce rHuEPO requirements in CPD patients, usually without adverse reaction and without exposing patients to an increased risk of peritonitis. More research is needed in the area of potential increased risk of infection in ESRD patients who are (1) infused with large doses of IVID, and (2) iron-overloaded.

A second generation synthesis of the MBr1 (globo-H) breast tumor antigen: new application of the n-pentenyl glycoside method for achieving complex carbohydrate protein linkages

A new synthesis of the hexasaccharide MBr1 antigen (globo-H) is reported. A revised construction with improved efficiency was necessary because an anti-cancer vaccine containing this antigen is entering phase II and phase III clinical trials for prostate cancer. The key feature of this second generation synthesis is the preparation of globo-H as its n-pentenyl glycoside. This group serves as an anomeric protecting group and as a linker for bioconjugation to carrier protein. The resultant synthesis allows for the production of suitable quantities of globo-H for clinical trials.

From the Laboratory to the Clinic: A Retrospective on Fully Synthetic Carbohydrate-Based Anticancer Vaccines Frequently used abbreviations are listed in the appendix

This review provides an account of our explorations into oligosaccharide and glycoconjugate construction for the creation and evaluation of vaccines based on carbohydrate-centered tumor antigens. Our starting point was the known tendency of transformed cells to express selective carbohydrate motifs in the form of glycoproteins or glycolipids. Anticancer vaccines derived from carbohydrate-based antigens could be effective targets for immune recognition and attack. Obtaining significant quantities of such structures from natural sources is, however, extremely difficult. With the total synthesis of tumor-associated carbohydrate antigens accomplished, we began to evaluate at the clinical level whether the human immune system can respond to such fully synthetic antigens in a focused and useful way. Toward this goal, we have merged the resources of chemistry and immunology in an attack on the problem. The synthesis and immunoconjugation of various tumor-associated carbohydrate antigens and the results of such constructs in mice vaccinations will be described. For fashioning an effective vaccine, conjugation to a suitable immunogenic carrier was necessary and conjugates of KLH (keyhole limpet cyanin) have consistently demonstrated the relevant immunogenicity. Preclinical and clinical studies with synthetic conjugate carbohydrate vaccines show induction of IgM- and IgG-antibody responses. Another approach to anticancer vaccines involves the use of clustered glycopeptides as targets for immune attack. Initial attention has been directed to mucin related O-linked glycopeptides. Synthetic trimeric clusters of glycoepitopes derived from the Tn-, TF- and Lewis(y)-antigens, appropriately bioconjugated, have been demonstrated to be immunogenic. The hope is that patients immunized in an adjuvant manner with synthetic carbohydrate vaccines would produce antibodies reactive with cancer cells and that the production of such antibodies would mitigate against tumor spread, thereby enabling a more favorable survival and "quality of life" prognosis.

Characterization of five catalytic activities associated with the NADPH:2-ketopropyl-coenzyme M [2-(2-ketopropylthio)ethanesulfonate] oxidoreductase/carboxylase of the Xanthobacter strain Py2 epoxide carboxylase system

The bacterial metabolism of propylene proceeds by epoxidation to epoxypropane followed by carboxylation to acetoacetate. Epoxypropane carboxylation is a minimetabolic pathway that requires four enzymes, NADPH, NAD(+), and coenzyme M (CoM; 2-mercaptoethanesulfonate) and occurs with the overall reaction stoichiometry: epoxypropane + CO(2) + NADPH + NAD(+) + CoM --> acetoacetate + H(+) + NADP(+) + NADH + CoM. The terminal enzyme of the pathway is NADPH:2-ketopropyl-CoM [2-(2-ketopropylthio)ethanesulfonate] oxidoreductase/carboxylase (2-KPCC), an FAD-containing enzyme that is a member of the NADPH:disulfide oxidoreductase family of enzymes and that catalyzes the reductive cleavage and carboxylation of 2-ketopropyl-CoM to form acetoacetate and CoM according to the reaction: 2-ketopropyl-CoM + NADPH + CO(2) --> acetoacetate + NADP(+) + CoM. In the present work, 2-KPCC has been characterized with respect to the above reaction and four newly discovered partial reactions of relevance to the catalytic mechanism, and each of which requires the formation of a stabilized enolacetone intermediate. These four reactions are (1) NADPH-dependent cleavage and protonation of 2-ketopropyl-CoM to form NADP(+), CoM, and acetone, a reaction analogous to the physiological reaction but in which H(+) is the electrophile; (2) NADP(+)-dependent synthesis of 2-ketopropyl-CoM from CoM and acetoacetate, the reverse of the physiologically important forward reaction; (3) acetoacetate decarboxylation to form acetone and CO(2); and (4) acetoacetate/(14)CO(2) exchange to form (14)C(1)-acetoacetate and CO(2). Acetoacetate decarboxylation and (14)CO(2) exchange occurred independent of NADP(H) and CoM, demonstrating that these substrates are not central to the mechanism of enolate generation and stabilization. 2-KPCC did not uncouple NADPH oxidation or NADP(+) reduction from the reactions involving cleavage or formation of 2-ketopropyl-CoM. N-Ethylmaleimide inactivated the reactions forming/using 2-ketopropyl-CoM but did not inactivate acetoacetate decarboxylation or (14)CO(2) exchange reactions. The biochemical characterization of 2-KPCC and the associated five catalytic activities has allowed the formulation of an unprecedented mechanism of substrate activation and carboxylation that involves NADPH oxidation, a redox active disulfide, thiol-mediated reductive cleavage of a C-S thioether bond, the formation of a CoM:cysteine mixed disulfide, and enolacetone stabilization.

A disturbed child's use of a public event: Cotard's syndrome in a ten-year-old

Public events can be incorporated into the mental life and life narratives of children with psychiatric illnesses. A 10-year-old boy who was not in Oklahoma City at the time of the 1995 bombing of the Murrah Federal Building and who knew no one directly impacted, claimed that he himself was dead, then that his grandfather, and finally that a peer and the peer's family had been killed in the blast. This is the first known reported case of Cotard's syndrome, the delusion of being dead, in a prepubescent child. The article also explores the relationships between this boy's symptoms, transference phenomena, real life events, themes of loss, abandonment, neglect, and death, and his fabricated stories.

Postpartum thyroid dysfunction: clinical assessment and relationship to psychiatric affective morbidity

OBJECTIVE

Postpartum thyroid dysfunction (PPTD), diagnosed using biochemical criteria, is usually transient with a wide range of reported prevalence rates. The specific clinical and psychiatric morbidity associated with PPTD is still uncertain. The aims of the study were to determine the point prevalence of PPTD in Australian women at 6 months postpartum and to assess the specific clinical and psychiatric morbidity in these women.

DESIGN

Women who were Caucasian, aged 20-45 years and 4.5-5.5 months postpartum, were randomly selected and invited into the study. The respondents were assessed for biochemical and psychiatric morbidity. PPTD for this study was defined as TSH or free T4 outside the adult reference range. A double blind clinical assessment of PPTD women and their matched controls used standardized clinical hypo- and hyperthyroid clinical indices.

PATIENTS

From the total randomly selected sample size of 1816 women, 748 participated.

MEASUREMENTS

Biochemical measurements were serum TSH, free T4, microsomal antibody (MsAb) and thyroid peroxidase antibody (TPOAb), and thyroid receptor antibodies (only in women with low TSH). Psychiatric assessment involved screening all participants using the General Health Questionnaire 28, followed by classifying and quantifying severity of cases using DSM-III-R categories for depression and anxiety. Clinical signs and symptoms of hypo- and hyper-thyroidism were measured using weighted standardized indices. Thyroid size was assessed by palpation. Achilles tendon reflex time was measured by photomotograph.

RESULTS

The prevalence of PPTD in the participants was 11.5% (95% CI 9.2-13. 8%), giving a minimum prevalence for the randomly selected sample of 4.7% (95% CI 3.7-5.7%). In the PPTD women, 54% had an elevated TSH, 30% had a suppressed TSH and the remainder had a low fT4 and normal TSH. Positive thyroid autoantibody titres in the PPTD group were 46. 5% for microsomal antibody (MsAb) and 63.9% for thyroid peroxidase antibody (TPOAb), and in the non-PPTD group were 1.7% and 4.9%, respectively. The 6 month point prevalence rates of depression, generalized anxiety disorder and panic disorder and/or agoraphobia were 9.4%, 1.4% and 3.1%, respectively. No relationship was found between PPTD status and the diagnosis of current depression or between thyroid antibody status and current depression. In women who were diagnosed as anxious at the time of assessment, the number of anxiety symptoms was higher in the PPTD group (P < 0.05). There was no difference in signs and symptom scores for the hypo- and hyper-thyroid clinical indices between PPTD women and their controls.

CONCLUSION

This study has shown a high prevalence of postpartum thyroid dysfunction but there was no difference in the clinical and psychiatric signs and symptoms between cases and controls. In the social, psychological, physical and endocrine setting of the postpartum period, women with postpartum thyroid dysfunction are identifiable by the attending physician only by their abnormal thyroid function tests.

A role for coenzyme M (2-mercaptoethanesulfonic acid) in a bacterial pathway of aliphatic epoxide carboxylation

The bacterial metabolism of short-chain aliphatic alkenes occurs via oxidation to epoxyalkanes followed by carboxylation to beta-ketoacids. Epoxyalkane carboxylation requires four enzymes (components I-IV), NADPH, NAD(+), and a previously unidentified nucleophilic thiol. In the present work, coenzyme M (2-mercaptoethanesulfonic acid), a compound previously found only in the methanogenic Archaea where it serves as a methyl group carrier and activator, has been identified as the thiol and central cofactor of aliphatic epoxide carboxylation in the Gram-negative bacterium Xanthobacter strain Py2. Component I catalyzed the addition of coenzyme M to epoxypropane to form a beta-hydroxythioether, 2-(2-hydroxypropylthio)ethanesulfonate. Components III and IV catalyzed the NAD(+)-dependent stereoselective dehydrogenation of R- and S-enantiomers of 2-(2-hydroxypropylthio)ethanesulfonate to form 2-(2-ketopropylthio)ethanesulfonate. Component II catalyzed the NADPH-dependent cleavage and carboxylation of the beta-ketothioether to form acetoacetate and coenzyme M. These findings evince a newfound versatility for coenzyme M as a carrier and activator of alkyl groups longer in chain-length than methane, a function for coenzyme M in a catabolic pathway of hydrocarbon oxidation, and the presence of coenzyme M in the bacterial domain of the phylogenetic tree. These results serve to unify bacterial and Archaeal metabolism further and showcase diverse biological functions for an elegantly simple organic molecule.

After the bombing: public scenarios and the construction of meaning

In both our folk psychology and mental health practice, we adhere to the modernist view that a crisis is something that an individual has. A crisis is either something that happens to people or which people bring on themselves because of character pathology. On the other hand, postmodern theorists now draw our attention to how processes of interaction provide opportunities for certain characterizations to emerge and disipate. Both the conceptualization of an event as a crisis and the scenarios of how it is best understood arise within a community and emerge out of the communal construction of meaning. In this process in Oklahoma City, bystanders, politicians, pilgrims and news media played a role of great significance. Whether local or from afar, they became a community of observers who interacted with one another and looked to one another for verification as to what counted as a crisis and what behavior was appropriate. Lindy has observed that traumatized individuals are often surrounded quickly by a small network of trusted people who serve to buffer and protect them and who define what is helpful and what constitutes further trauma. Here, in Oklahoma, however, a wider public defined the event as a crisis, elaborated on it, and have gradually transformed it into almost mythic proportions, a process now exemplified in the construction of the Oklahoma City National Monument. However, they have also endorsed diverse other scenarios, not all of which have facilitated appropriate grieving, repair of life-disruption, or moving on. All, however, seem to have given a sense of meaning to the event. In this rich matrix, some survivors and their families have felt helped. Others have felt exploited. Still others have wanted to forget the whole thing and to avoid anything that reminded them of it. Of the would-be helpers, some felt unjustly rejected and unappreciated. Others felt appreciated, useful, and even enriched. However, a true legacy of the bombing may well be the metalogue it can precipitate and advance about the relationship between individuals and society, and especially the relationship between our individual life-stories and larger public scenarios, and the effects these scenarios have on the questions we can ask, what we can perceive and what solutions we can create.

Two short-chain dehydrogenases confer stereoselectivity for enantiomers of epoxypropane in the multiprotein epoxide carboxylating systems of Xanthobacter strain Py2 and Nocardia corallina B276

Epoxide carboxylase from the bacterium Xanthobacter strain Py2 is a multicomponent enzyme system which catalyzes the pyridine nucleotide-dependent carboxylation of aliphatic epoxides to beta-ketoacids as illustrated by the reaction epoxypropane + CO2 + NADPH + NAD+ --> acetoacetate + H+ + NADP+ + NADH. The combination of four distinct proteins, designated components I-IV, are required for the reconstitution of epoxide carboxylase activity with racemic mixtures of short-chain (C3-C5) terminal epoxyalkanes. In this work, components III and IV of the epoxide carboxylase system are shown to confer specificity for epoxyalkane enantiomers. Components I-III supported the carboxylation of (R)-epoxypropane, while components I, II, and IV supported the carboxylation of (S)-epoxypropane. At fixed concentrations of components I and II, the rates of (R)- and (S)-epoxypropane carboxylation saturated with increasing concentrations of component III or IV to give identical maximal rates for the two epoxide substrates. (S)-Epoxypropane was an inactivator of (R)-epoxypropane carboxylation by components I- III, while (R)-epoxypropane was an inactivator of (S)-epoxypropane carboxylation by components I, II, and IV. These inactivating effects were fully reversed upon the addition of the correct complementing dehydrogenase component. Amino acid sequence analysis of components III and IV demonstrates that they belong to the short-chain dehydrogenase/reductase (SDR) family of enzymes. Both components contain highly conserved residues within the coenzyme binding fold and catalytic regions found in SDR enzymes. Components III and IV are proposed to catalyze the NAD+-dependent abstraction of a hydride from a chiral secondary alcohol-like intermediate bound to the active site component of the enzyme system to form the corresponding beta-ketone intermediate. A multicomponent epoxide carboxylase system was purified to homogeneity from Nocardia corallina B276, a bacterium phylogenetically unrelated to Xanthobacter Py2, and found to consist of four proteins with functions identical to those of the Xanthobacter Py2 system. The stereoselective dehydrogenases of the Xanthobacter epoxide carboxylase system were able to substitute for the corresponding components of the N. corallina system when using (R)- and (S)-epoxypropane as substrates, and vice versa. These results provide the first demonstration of the involvement of stereospecific dehydrogenases in aliphatic epoxide metabolism and provide new insights into microbial strategies for the utilization of chiral organic molecules.

Avoidance in trauma: conscious and unconscious defense, pathology, and health

Drawing from our work with children seen following the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, this article describes clinical aspects of avoidance in traumatized children and their families. Avoidance in traumatized children and their families seems a final common pathway arising from a number of diverse factors. The importance of particular factors for assessment and treatment is emphasized.

Fabricated trauma exposure: an analysis of cognitive, behavioral, and emotional factors

The 1995 Oklahoma City bombing was a disaster of unparalleled dimension in the United States. The professional response included the development of systematic clinical and research programs. This article describes the case of a child who, as a participant in a research study, appeared to fabricate a story of bomb-related loss. The research and clinical records of this child were examined and analyzed according to the factors and conditions that might underlie this fabrication. These include issues related to memory and suggestibility, symptom contagion, and mass hysteria. The report describes the role of psychological vulnerability in trauma and this child's coping and adaptation.

Long- and short-looking infants' recognition of symmetrical and asymmetrical forms

Adults process symmetrical visual forms more rapidly than asymmetrical visual forms, presumably because symmetrical forms are amenable to a global visual encoding strategy. Individual differences in look duration during infancy have been hypothesized to covary with different modes of visual intake and encoding, with longer look durations reflecting encoding based on prolonged inspection of local visual properties, and briefer look durations reflecting encoding based on more of a global, or global-to-local processing sequence. This hypothesis predicts that short-looking infants would process symmetrical stimuli faster than asymmetrical stimuli, but that long-looking infants would not. Three experiments are described here in which this prediction is tested. Results were in general accord with the prediction, and provide further support for the hypothesis that individual differences in look duration may reflect different modes of visual encoding or inspection.

Crossover use of donated blood for autologous transfusion: report of the Council on Scientific Affairs, American Medical Association

BACKGROUND

Controversy exists concerning whether the costs and potential risks outweigh the potential benefits of "crossover" use in the general blood supply of unutilized blood that was donated for autologous transfusion.

STUDY DESIGN AND METHODS

Published articles and reports were identified through systematic search of MEDLINE and review of references cited in previously identified articles, textbooks, and reports. Consultation was made with experts in blood donation and transfusion. Additional peer review was received from the American Medical Association (AMA) Council on Scientific Affairs

RESULTS

Concern over infectious disease transmission has led to increased interest in and support for autologous transfusion for individuals having planned surgeries. Different requirements exist for collection, labeling, and screening of blood to be used for autologous versus allogeneic transfusions; therefore, procedures for diverting autologous blood donations to the general blood supply involve considerable expense. Several cost-effectiveness studies of autologous blood donation and transfusion conclude that currently this "crossover" appears to be an expensive procedure yielding little increased benefit from a societal perspective.

CONCLUSIONS

The recommendations in this report were adopted as AMA Policy at the AMA Annual Meeting in June 1997. The AMA does not encourage blood collection programs to "cross over" units donated for autologous use to the allogeneic blood supply. Practice guidelines are needed, and should be utilized to ensure parsimony in the use of autologous blood donations and transfusions.

Identification and characterization of epoxide carboxylase activity in cell extracts of Nocardia corallina B276

The metabolism of aliphatic epoxides (epoxyalkanes) by the alkene-utilizing actinomycete Nocardia corallina B276 was investigated. Suspensions of N. corallina cells grown with propylene as the carbon source readily degraded propylene and epoxypropane, while suspensions of glucose-grown cells did not. The addition of propylene and epoxypropane to glucose-grown cells resulted in a time-dependent increase in propylene- and epoxypropane-degrading activities that was prevented by the addition of rifampin and chloramphenicol. The expression of alkene- and epoxide-degrading activities was correlated with the high-level expression of several polypeptides not present in extracts of glucose-grown cells. Epoxypropane and epoxybutane degradation by propylene-grown cell suspensions of N. corallina was stimulated by the addition of CO2 and inhibited by the depletion of CO2. Cell extracts catalyzed the carboxylation of epoxypropane to form acetoacetate in a reaction that was dependent on the addition of CO2, NAD+, and a reductant (NADPH or dithiothreitol). In the absence of CO2, epoxypropane was isomerized by cell extracts to form acetone at a rate approximately 10-fold lower than the rate of epoxypropane carboxylation. Methylepoxypropane was found to be a time-dependent, irreversible inactivator of epoxyalkane-degrading activity. These properties demonstrate that epoxyalkane metabolism in N. corallina occurs by a carboxylation reaction forming beta-keto acids as products and provide evidence for the involvement in this reaction of an epoxide carboxylase with properties and cofactor requirements similar to those of the four-component epoxide carboxylase enzyme system of the gram-negative bacterium Xanthobacter strain Py2 (J. R. Allen and S. A. Ensign, J. Biol. Chem. 272:32121-32128, 1997). The addition of epoxide carboxylase component I from Xanthobacter strain Py2 to methylepoxypropane-inactivated N. corallina extracts restored epoxide carboxylase activity, and the addition of epoxide carboxylase component II from Xanthobacter Py2 to active N. corallina extracts stimulated epoxide isomerase rates to the same levels observed with the purified Xanthobacter system. Antibodies raised against Xanthobacter strain Py2 epoxide carboxylase component I cross-reacted with a polypeptide in propylene-grown N. corallina extracts with the same molecular weight as component I but did not cross-react with glucose-grown extracts. Together, these results suggest a common pathway of epoxyalkane metabolism for phylogenetically distinct bacteria that involves CO2 fixation and the activity of a multicomponent epoxide carboxylase enzyme system.

New roles for CO2 in the microbial metabolism of aliphatic epoxides and ketones

Short-chain aliphatic epoxides and ketones are two classes of toxic organic compounds formed biogenically and anthropogenically. In spite of their toxicity, these compounds are utilized as primary carbon and energy sources or are generated as intermediate metabolites in the metabolism of other compounds (e.g., alkenes, alkanes, and secondary alcohols) by a number of diverse bacteria. One bacterium capable of using both classes of compounds is the gram-negative aerobe Xanthobacter strain Py2. Studies of epoxide and ketone (acetone) metabolism by Xanthobacter strain Py2 have revealed a central role for CO2 in these processes. Both classes of compounds are metabolized by carboxylation reactions that produce beta-keto acids as products. The epoxide- and ketone-converting enzymes are distinct carboxylases with molecular properties and cofactor requirements unprecedented for other carboxylases. Epoxide carboxylase is a four-component multienzyme complex that requires NADPH and NAD+ as cofactors. In the course of epoxide carboxylation, a transhydrogenation reaction occurs wherein NADPH undergoes oxidation and NAD+ undergoes reduction. Acetone carboxylase is a multimeric (three-subunit) ATP-dependent enzyme that forms AMP and inorganic phosphate as ATP hydrolysis products in the course of acetone carboxylation. Recent studies have demonstrated that acetone metabolism in diverse anaerobic bacteria (sulfate reducers, denitrifiers, phototrophs, and fermenters) also proceeds by carboxylation reactions. ATP-dependent acetone carboxylase activity has been demonstrated in cell-free extracts of the anaerobic acetone-utilizers Rhodobacter capsulatus, Rhodomicrobium vannielii, and Thiosphaera pantotropha. These studies have identified new roles for CO2 as a cosubstrate in the metabolism of two classes of important xenobiotic compounds. In addition, two new classes of carboxylases have been identified, the investigation of which promises to reveal new insights into biological strategies for the fixation of CO2 to organic substrates.

Clinical research: assessing the future in a changing environment; summary report of conference sponsored by the American Medical Association Council on Scientific Affairs, Washington, DC, March 1996

Concerns about funding of clinical research underlie all other problems identified at the Council on Scientific Affairs conference. Future National Institutes of Health (NIH) budgets are likely to be constant at best, and the general public expects cost containment to be an ongoing goal; this is exacerbated by the impending Medicare Trust Fund crisis. Meanwhile, traditional financial support of clinical research in academic medical centers (AMCs) through cross-subsidization is imperiled by competitive pressures largely caused by managed care. Although managed care organizations (MCOs) are potentially rich sources of funding and other resources, and some not-for-profit companies are conducting some research, for-profit MCOs have not demonstrated an understanding of the importance of clinical research. Young physicians are being discouraged from careers as clinical researchers and established investigators are "dropping out" because of demands for clinical productivity and competition for research grants, loss of patients/research subjects to managed care, perceived lack of status and compensation, and overall uncertainty about continued financial support. Efforts to assist current and potential clinical investigators are discussed in this report. Loss of patients, denial of reimbursement, and competition with MCOs and contract research organizations (CROs) have placed AMCs under unprecedented pressure. However, research centers located in AMCs have allowed investigators to conduct clinical research by providing a "protected environment." Furthermore, many AMCs are determined to continue conducting clinical research and are addressing related problems. Although the NIH will continue to be a major source of funding for clinical research, partnerships between various private and public entities provide important opportunities to maximize the productivity of all individuals and institutions involved. Potential partnerships include MCOs, AMCs, CROs, pharmaceutical companies and other industry, the Department of Defense, the Veterans Health Administration, practice-based physicians, and private foundations and patient support groups. "Partnerships in advocacy" for clinical research will be essential. Efforts to recruit for-profit MCOs to the clinical research endeavor identified in this report include (1) emphasizing issues of interest to them (eg, outcomes research); (2) stressing the significance of some research to the marketplace; (3) developing criteria to distinguish individual MCOs on the basis of their contribution to the public interest; (4) equating money spent on research with "R&D dollars" spent in nonmedical business enterprises; and (5) educating purchasers of health care (eg, corporate health plan directors) about clinical research. Conducting clinical research in all managed care settings requires leadership, the understanding and cooperation of physicians and support staff, wise use of limited resources (ie, funding only the best research projects), sound methodology, and above all, the perception that the research will ultimately improve patient care.

Adequacy of CPD: comparing Kt/V and creatinine clearance

Presently, adequate dialysis in continuous peritoneal dialysis (CPD) patients is assessed by monitoring urea kinetics (Kt/V) or by measuring the total creatinine clearance (CC). Target Dialysis Outcome Quality Initiative (DOQI) goals are a weekly Kt/V of at least 2.0, and a CC of at least 60 L/wk per 1.73 m2. One hundred and four CPD patients in the New Haven continuous ambulatory peritoneal dialysis (CAPD) unit had their most recent Kt/V and CC reviewed. Of these patients, 58.7% attained the DOQI goals for Kt/V and CC, 14.4% had an acceptable Kt/V but low CC, 11.5% had an acceptable CC but low Kt/V, and 15.4% had both low Kt/V and low CC. A CC > 60 L/week per 1.73 m2 was associated with a residual renal function of > 25 L/wk per 1.73 m2. For a Kt/V of > 2.0, good residual renal function was helpful but not essential. A question left unanswered is whether patients with a low Kt/V and an adequate CC or low CC and acceptable Kt/V need more dialysis.

Invasive aspergillosis in severely neutropenic patients over 18 years: impact of intranasal amphotericin B and HEPA filtration

The impact of intranasal amphotericin B and high-efficiency particulate air (HEPA) filtration on the incidence of invasive aspergillosis was reviewed in patients from 1977 to 1994 undergoing intensive chemotherapy. Overall, the incidence of proven invasive aspergillosis was reduced from 24.4% (1977-1984) to 7.1% (1985-1991) (P < 0.001) following the introduction of intranasal prophylaxis, but when probable cases of aspergillosis were included and lymphoma cases excluded, there was no change in incidence. Following the introduction of HEPA filtration, patient exposure to aspergillus spores as measured by air sampling was markedly reduced and there were no new cases of invasive aspergillosis. HEPA filtration proved effective in reducing invasive aspergillosis and has allowed increasingly aggressive treatment regimens to be introduced.

Stressors and development: a reciprocal relationship

In this article we have attempted to delineate the importance of developmental levels in a young person's response to stressors and, conversely, the effect of stressors on levels of development. In so doing, we isolated specific lines of development from their context. We neglected the important roles of rewards and punishments, permissions and prohibitions, family and community dynamics, values, stories and myths. Even in this simplified schema, we have not addressed the importance of protective and risk factors, neither of which are found in isolation; but all of these issues are the subject of articles elsewhere in this issue.

Of resilience, vulnerability, and a woman who never lived

One day we may be able to say with some degree of confidence that Factor A over a certain level + Factor B over a certain level + Factor C under a certain level + Factor X will produce Y level of functioning in domain X--in about 80% of cases. Despite advances in our knowledge about the influence of various protective and risk factors in development, health, and functioning, however, we still have good reason to remain humble. This article examines some of the advances and some of the problems in the study of resilience and vulnerability in children and adolescents.

What if Astyanax had survived? War, children, and youth

What, then, might have happened to Astyanax had he survived? He might have become a Greek slave and accepted his lot, or he might have felt loyalty and an obligation to his Trojan ancestry and organized acts of revenge. Depending on his personal characteristics and the people and the community that raised him, a number of outcomes are possible. The fact that after 3000 years we know little more than did the Homeric bards, however, gives us reason to be humble. There is evidence that each experience of loss or violence is additive and reduces coping ability. Although the psychologic disturbances of children and youth exposed to war do appear less intense than might have been expected, as Garmezy and Rutter noted in 1985, it is impossible to know the cost, the vulnerabilities that have been veiled, and what might have been. Perhaps the most remarkable thing is how some children seem able to transcend their misfortunes and even to be steeled by them. Coles has recorded how a 6-year-old, African-American girl, initiating school desegregation in New Orleans in the face of mob violence and daily threats to her life, told him that if she managed to get through with some success, she had an explanation: "It will be because there is more to me than I ever realized."

The effects of linear acceleration on distortion product otoacoustic emissions in human ears

BACKGROUND

The effect of high levels of linear acceleration (G) on the cochlea has never been studied prospectively.

HYPOTHESIS

Linear acceleration at high levels has no effect on the human cochlea as demonstrated by a comparison of pre- and post-exposure measurements.

METHODS

There were 22 healthy volunteers who underwent exposure to up to 9 G in a military aviation training centrifuge. Prior to exposure they were screened for cochleovestibular disorders and underwent tympanometry, audiometry and distortion product otoacoustic emissions testing (DPOAE). Immediately after exposure, they underwent serial testing of each of these parameters until they returned to baseline.

RESULTS

There was no significant change in tympanometry in any subject. Audiometry revealed a temporary threshold shift of 30 db at 6 kHz in one ear of a single subject. This was accompanied by a complete loss of DPOAE at the same frequency. DPOAE did not return to baseline at 2 weeks even though the audiogram had reverted to baseline by 8 d. Four other ears displayed significant losses of emissions at single frequencies without an accompanying change on the audiogram.

CONCLUSIONS

This study demonstrates that accelerative stress may cause transient injury to the cochlea. The mechanism of injury due to acceleration is probably ischemia, although a purely mechanical effect on the outer hair cells cannot be precluded. These data also reinforce a growing body of evidence that demonstrates the greater sensitivity of DPOAE over psychoacoustic testing in detecting early or subclinical cochlear damage.

Stress in children exposed to violence. Reenactment and rage

Violence is a major public health problem that increasingly involves children and adolescents as both victims and witnesses. Exposure to violence is now implicated in the development of stress conditions. This article uses Terr's typology to describe responses to various kinds of violence and suggests that the posttraumatic stress model adds a unique dimension to our understanding of the effects of violence on children and adolescents.

Purification to homogeneity and reconstitution of the individual components of the epoxide carboxylase multiprotein enzyme complex from Xanthobacter strain Py2

Epoxide metabolism in the aerobic bacterium Xanthobacter strain Py2 proceeds by an NADPH- and NAD+-dependent carboxylation reaction that forms beta-keto acids as products. Epoxide carboxylase, the enzyme catalyzing this reaction, was resolved from the soluble fraction of cell-free extracts into four protein components that are obligately required for functional reconstitution of epoxide carboxylase activity. One of these components, component II, has previously been purified and characterized as an NADPH:disulfide oxidoreductase. In the present study, the three additional epoxide carboxylase components have been purified to homogeneity and characterized. These component proteins are as follows: component I, a homohexameric protein consisting of 41.7-kDa subunits; component III, a dimeric protein consisting of 26.0- and 26.2-kDa polypeptides; and component IV, a dimeric protein consisting of a single 25.4-kDa polypeptide. Component I contained 5 mol of tightly bound zinc per mol of protein. Component I was specifically inactivated by methylepoxypropane, a time-dependent irreversible inactivator of epoxide carboxylase activity, suggesting that this component plays an integral role in epoxide binding and activation. No metals or organic cofactors were detected for components III and IV. The molecular weights, N-terminal sequences, and amino acid compositions of the purified epoxide carboxylase components were determined and found to correlate with open reading frames within and adjacent to a cloned fragment of DNA that complements Xanthobacter Py2 mutants defective in epoxide degradation. Using the purified epoxide carboxylase system, epoxide carboxylation was found to be stoichiometrically coupled to the transhydrogenation of pyridine nucleotide cofactors according to the following equation: epoxypropane + CO2 + NADPH + NAD+ --> acetoacetate + H+ + NADP+ + NADH.

Characterization of three protein components required for functional reconstitution of the epoxide carboxylase multienzyme complex from Xanthobacter strain Py2

Epoxide carboxylase from Xanthobacter strain Py2 catalyzes the reductant- and NAD+-dependent carboxylation of aliphatic epoxides to beta-keto acids. Epoxide carboxylase from Xanthobacter strain Py2 has been resolved from cell extracts by anion-exchange chromatography into three protein components, designated I, II, and III, that are obligately required for functional reconstitution of epoxide carboxylase activity. Component II has been purified to homogeneity on the basis of its ability to complement components I and III in restoring epoxide carboxylase activity. Purified component II had a specific activity for epoxide carboxylation of 41.8 mU x min(-1) x mg(-1) when components I and III were present at saturating levels. The biochemical properties of component II reveal that it is the flavin-containing NADPH:disulfide oxidoreductase that was recently shown by other means to be associated with epoxide degradation activity in Xanthobacter strain Py2 (J. Swaving, J. A. M. de Bont, A. Westphal, and A. Dekok, J. Bacteriol. 178:6644-6646, 1996). The rate of epoxide carboxylation was dependent on the relative concentrations of the three carboxylase components. At fixed concentrations of two of the components, epoxide carboxylation rates were saturated in a hyperbolic fashion by increasing the concentration of the third variable component. Methylepoxypropane has been characterized as a time-dependent, irreversible inactivator of epoxide carboxylase activity that is proposed to be a mechanism-based inactivator of the enzyme. The addition of component I, but not that of component II or III, to methylepoxypropane-inactivated cell extracts restored epoxide carboxylase activity, suggesting that component I contains the epoxide binding and activation sites.