Synthesis and characterization of 2D and 3D structures from organic derivatives of polyoxometalate clusters: role of organic moiety, counterion, and solvent

New organic derivatives of "inverse-Keggin" polyoxometalate (POM) clusters, [Mo(12)O(46)(AsR)(4)](4-) (R = C(6)H(4)-4-COOH, C(6)H(3)-4-OH-3-NO(2), C(6)H(4)-4-OH), have been synthesized. Structures of the corresponding sodium or iron salts were elucidated by single-crystal X-ray diffraction and shown to be 3D structures connected through hydrogen bonds and/or O-Na-O linkages. Parameters which influence the final solid-state architecture, such as the crystallizing solvent, organic moiety, and counterions, have been examined. The hydrogen-bonding ability of the solvent affects the connectivity of the POM clusters through interactions with the organic group and the inorganic core. The organic groups influence the structure through hydrogen bonds to other organic groups, to neighboring clusters, and/or to solvent molecules. Hydrogen bonding between the organic groups and the solvent appears to inhibit some possible connectivity patterns, such as the hydrogen-bonded dimerization of carboxylic acid groups. Na(+) ions were found directly bonded to the cluster oxo ligands and provided linkages between clusters. Larger cations, such as transition metals, did not show this interaction, and other bonding methods dominated.

Trimethoprim-sulfamethoxazole (TMP-SMZ) dose escalation versus direct rechallenge for Pneumocystis Carinii pneumonia prophylaxis in human immunodeficiency virus-infected patients with previous adverse reaction to TMP-SMZ

Trimethoprim-sulfamethoxazole (TMP-SMZ) is the most effective Pneumocystis carinii pneumonia (PCP) prophylactic agent, but adverse reactions are common among human immunodeficiency virus (HIV)-infected patients and limit its use. This randomized, double-blind controlled trial compared 2 methods of TMP-SMZ reintroduction, 6-day dose escalation and direct rechallenge, for PCP prophylaxis in HIV-infected patients who had experienced previous treatment-limiting reactions. The primary end point was the ability to take single-strength TMP-SMZ daily for 6 months. Seventy-five percent of the dose-escalation group and 57% of the direct-rechallenge group continued to receive daily single-strength TMP-SMZ for 6 months (P= .014). Among premature discontinuations, 58% of the dose-escalation group and 70% of the direct-rechallenge group were due to adverse reactions. None of these reactions was serious. This study provides evidence that it is possible to successfully reintroduce TMP-SMZ to a significant proportion of HIV-infected patients who have experienced mild-to-moderate treatment-limiting adverse reactions.

New modality for treatment of resistant anastomotic strictures after radical prostatectomy: UroLume urethral stent

A new approach for the treatment of vesicourethral anastomotic stricture after radical retropubic prostatectomy is presented. The patient had failed treatment with bougies, balloon dilation, and cold-knife incision of the anastomotic area. Transurethral resection of the bladder neck resulted in a rapid recurrence of the stricture. He was successfully treated with insertion of a UroLume urethral stent. After 18 months of follow-up, the patient is symptom free.

Geochemistry of Bulgarian soils in villages affected and not affected by Balkan endemic nephropathy: a pilot study

Balkan endemic nephropathy (BEN) is a chronic tubulointerstitial disease whose mosaic-like distribution throughout the Balkans has not changed significantly since its initial description. In this study, we explored the hypothesis that the occurrence of BEN is linked with the environmental geochemistry of villages. Soil samples were collected from BEN and non-BEN villages in the Vratza region of Bulgaria. Samples were digested in nitric acid and analyzed for 22 elements by hexapole, inductively coupled plasma, and mass spectrometry. Selected results are that: 1) absolute concentrations from both types of villages were not enriched above "background" concentrations; and 2) copper, molybdenum, lead, and cadmium concentrations were higher in BEN than in non-BEN soils, while selenium concentrations were lower. Although geochemical differences between BEN and non-BEN villages were found, not all differences were statistically significant, in part due to a limited number of samples.

Telomerase activity and cytokeratin 20 as markers for the detection and followup of transitional cell carcinoma: an unfulfilled promise

PURPOSE

Telomerase activity compensates for the erosion of chromosomes and it has been detected in a wide variety of human tumors. Cytokeratin 20, an intermediate filament of epithelial cells, is expressed particularly in the urinary tract. These 2 molecules are candidates to become markers for the detection and followup of bladder carcinoma. We evaluate whether each molecule may serve as a potential marker and whether the 2 combined would improve the detection or followup of bladder carcinoma in a noninvasive manner.

MATERIALS AND METHODS

We obtained 44 morning urine samples from patients with transitional cell carcinoma patients and 26 from age matched patients with a wide variety of clinical disorders but no malignancy of any kind. A telomerase polymerase chain reaction-enzyme-linked immunosorbent assay kit was used to determine telomerase activity and cytokeratin 20 expression was determined by nested reverse transcriptase-polymerase chain reaction.

RESULTS

All samples tested positive for cytokeratin 8 expression, which verified epithelial cells in the urine samples. Of the 44 transitional cell carcinoma cases of all stages and grades 37 (84.1%) were positive for telomerase activity, 36 (81.8%) were positive for cytokeratin 20 expression and 65.9% were double positive. Of the 29 controls with various clinical conditions other that malignancy 22 (75.9%) were positive for telomerase activity, 13 (44.83%) were positive for cytokeratin 20 expression and 34.6% were double positive.

CONCLUSIONS

Telomerase activity and cytokeratin 20 expression are not specific for malignancy and may be detected in many nonmalignant pathological conditions. Therefore, their use as potential markers of bladder carcinoma should be carefully reevaluated.

Clinical and psychological course of diabetes from adolescence to young adulthood: a longitudinal cohort study

OBJECTIVE

To determine the clinical and psychological course of diabetes through adolescence and the relationship with glycemic control in young adulthood.

RESEARCH DESIGN AND METHODS

A longitudinal cohort study of adolescents recruited from the register of the outpatient pediatric diabetes clinic. A total of 76 individuals (43 male patients, 33 female patients) aged 11-18 years completed baseline assessments, and 65 individuals (86%) were reinterviewed as young adults (20-28 years of age). Longitudinal assessments were made of glycemic control (HbA(1c)), weight gain (BMI), and development of complications. Adolescents completed self-report questionnaires to assess emotional and behavioral problems as well as self-esteem. As young adults, psychological state was assessed by the Revised Clinical Interview Schedule and the self-report Brief Symptom Inventory.

RESULTS

Mean HbA(1c) levels peaked in late adolescence and were worse in female participants (average 11.1% at 18-19 years of age). The proportion of individuals who were overweight (BMI >25.0 kg/m(2)) increased during the 8-year period from 21 to 54% in female patients and from 2 to 28% in male patients. Serious diabetes-related events included death in one patient and cognitive impairment in two patients. Individuals in whom diabetic complications developed (25% of male patients and 38% of female patients) had significantly higher mean HbA(1c) levels than those without complications (difference 1.9%, 95% CI 1.1-2.7, P < 0.0001). Behavioral problems at baseline were related to higher mean HbA(1c) during the subsequent 8 years (beta = 0.15, SEM (beta) 0.04, P < 0.001, 95% CI 0.07-0.24).

CONCLUSIONS

The outcome for this cohort was generally poor. Behavioral problems in adolescence seem to be important in influencing later glycemic control.

Influence of psychiatric disorder on the controlling behaviour of mothers with 1-year-old infants. A study of women with maternal eating disorder, postnatal depression and a healthy comparison group

BACKGROUND

Certain styles of parental controlling behaviour influence child development. Work with mothers with eating disorders suggests that they may be particularly controlling of their infants.

AIMS

To examine the nature and specificity of maternal controlling behaviour in mothers with eating disorders compared with mothers who had experienced postnatal depression and a healthy comparison group.

METHOD

Mothers with eating disorders (n=34), postnatal depression (n=39) and a healthy comparison group (n=61) and their 12-month-old infants were observed during play and mealtimes, and blind ratings made of verbal and non-verbal control exerted by the mother.

RESULTS

Mothers in the eating disorder group used more verbal control, especially strong control. There were no differences between the groups on gentle verbal control and physical contact. Maternal dietary restraint was the one feature of eating disorder psychopathology associated with the use of verbal control. Marital criticism was also associated with the extent of verbal controlling behaviour.

CONCLUSIONS

Aspects of maternal control of infants were found to be specific to maternal eating disorder psychopathology.

Accuracy of the intra-operative radioguided localization of the sentinel lymph node (SLN) 24 hours after lymphoscintigraphy in patients with malignant melanoma

AIM

For optimized logistics for the sentinel lymphadenectomy (SL) it might be helpful for the clinics involved if a longer time period between the lymphoscintigraphy (LS) and surgery is possible. Therefore, we investigated if a precise localization of the sentinel lymph node is possible 24 hours after LS.

METHODS

78 patients with primary malignant melanoma (MM; n = 44) or with MM pre-operated by excisional biopsy (n = 34) were investigated. In 40 cases the tumor was localized on the trunk and in 38 cases on the extremities. Mean MM thickness was 2.68 mm (range: 0.29 to 12 mm). In all patients a lymphoscintigraphy (LS) with an average of 85 MBq of Tc-99m nanocolloid was performed one day prior to surgery. Immediately after tracer application dynamic data acquisition was started at a LFOV gamma camera followed by a whole body scan. With a hand-held gamma detector (C-Trak) 2, 4, 6, 8, and 24 hours after tracer administration the SLN was identified and the counts registered.

RESULTS

94 SLNs were identified in 87 lymphatic basins from which 86 could be resected. Nine MM showed two draining channels. After 24 hours 15.5% (as an average) of the initial counts could be measured in the SLN. The uptake in the SLN in pre-operated versus patients with primary tumor was statistically not significant (p = 0.4). In 16 cases (20.5%) the SLN was tumor positive. Four of those patients developed distant metastases and two died within the first year. None of the patients with negative SLN developed distant metastases or died.

CONCLUSION

The remaining activity in the SLN up to 24 hours after administration is sufficient for their intra operative localization. The method of lymphoscintigraphy and localization of the SLN by a hand-held gamma detector optimizes the intra operative identification of the SLN in patients with malignant melanoma.

Computed tomography for pancreatic diseases

CT has evolved over 24 years as an effective cross-sectional imaging modality for benign and malignant pancreatic diseases. Multiphase helical scanners with rapid infusion of intravenous contrast medium allow for the delineation of pancreatic parenchymal, arterial, and venous studies with identification of malignant and benign lesions. Therapeutic applications abound, and CT drainage of postoperative fluid collections, pseudocysts, and abscesses will have an increasing role in the new millennium.

Microscopic analysis and significance of vascular architectural complexity in renal cell carcinoma

The objective of this study was to evaluate the utility of measuring microvessel fractal dimension (MFD) as a parameter of architectural microvascular complexity in localized renal cell carcinoma (RCC). Forty-nine patients with low-stage clear cell RCC were assessed in a 9-year follow-up retrospective study. Tumor vessels were visualized with the endothelial marker CD34. Tumor microvessel density (MVD) was measured by computerized morphometry. Fractal analysis of the RCC microvascular network was performed and the MFD was computed in each case. Correlation between tumor vascular parameters, histological grade, extent of tumor necrosis and patient survival were tested by uni- and multivariate analyses. A significant correlation was found between tumor grade and decreased survival (P = 0.04). The extent of macroscopic tumor necrosis also significantly correlated with poor prognosis (P = 0.0001). Survival analysis revealed a significantly higher MVD in patients who survived longer than 5 years as compared with those who died before the end of the 5-year follow-up period (MVD = 10.8 +/- 4.7% versus 6.4 +/- 3.7%; P = 0.03). MVD was also inversely associated with the extent of tumor necrosis (P = 0.03). Microvessel fractal dimension was significantly higher in low- as compared with high-grade tumors (1.55 +/- 0.11 versus 1.45 +/- 0.15; P = 0.03). Survival analysis revealed a significantly higher MFD in those who lived >5 years as compared with those who died earlier (1.56 +/- 0.11 versus 1.46 +/- 0.15; P = 0.02). The MFD was inversely associated with the extent of tumor necrosis (P = 0.01). Multivariate analysis revealed that the MFD was the only significant factor to correlate with tumor necrosis, and that tumor necrosis was the only independent predictor of patient survival. These results indicate that the analysis of MFD as a marker of tumor microvascular complexity may provide important prognostic information as well as novel insight into the biology of tumor angiogenesis.

A quantitative evaluation of monitoring networks for region-specific nitrate reduction policies

Modern environmental policy implementation in many developed countries is increasingly regionally oriented. Regional governments have undertaken measures designed for the specific needs of the region but, so far, the resulting change in environmental quality has hardly been monitored. This study develops a method for the quantitative evaluation of region-specific environmental policy. Two forms of monitoring are distinguished: monitoring of performance of policy measures and monitoring of environmental quality. This study investigates two regions in the Netherlands where region-specific policy has been implemented. Performance monitoring focused on reduction of nitrate leaching to groundwater. Leaching reductions were calculated with simple models or rules of thumb. Quality monitoring focused on nitrate concentrations under grassland and other land use. An analysis of variance showed significant differences between different soil units. Stratified kriging was applied for spatial interpolation, showing within-unit variability. The current monitoring network could be improved by using a more regular type of grid.

Effects of allogeneic bone marrow transplantation on recipient bone mineral density: A prospective study

Allogeneic bone marrow transplant (BMT) recipients have many known risk factors for developing decreased bone mineral density (BMD) after transplantation. We performed a prospective sequential evaluation of BMD in the lumbar spine and nondominant hip using dual-energy x-ray absorptiometry (DEXA) in a cohort of 47 adult patients (median age, 43 years) who were undergoing radiation-based BMT for hematologic malignancies. Baseline DEXA studies were performed before BMT and repeated at 3 to 4 months, 6 to 8 months, and 12 to 14 months after BMT. The majority of patients (60%) had been minimally treated with combination cytotoxic chemotherapy, having received no more than 1 treatment regimen before BMT. Graft-versus-host disease prophylaxis consisted of cyclosporine in combination with either methotrexate or prednisone, or both. Mean lumbar spine and hip BMD were normal before BMT (spine: 1.01 g/cm2, z score = 96%; hip: 0.86 g/cm2, z score = 100%) and gradually decreased (spine: 0.98 g/cm2, z score = 94%; hip: 0.76 g/cm2, z score = 91%) at 12 to 14 months. These declines were statistically significant (P < .006 and < .002 for lumbar spine; P < .001 and < .001 for hip). In addition, the sharpest decline occurred during the first 6 months after BMT and was more marked in the hip than the lumbar spine. These data suggest that BMT adversely affects BMD in this patient population.

Surface modification of mesoporous, macroporous, and amorphous silica with catalytically active polyoxometalate clusters

Transition-metal-substituted polyoxometalates (TMSP) of the type [MII(H2O)PW11O39]5- (M = Co, Zn) and [SiW9O37(CoII(H2O))3]10- have been chemically anchored to modified macroporous (400 nm pores), mesoporous (2.8 nm pores), and amorphous silica surfaces. The materials were characterized by solid-state 31P MAS NMR, UV-vis, FT-IR spectroscopy, and N2 adsorption experiments to verify cluster attachment and the structure of the TMSP on the support. On the basis of the spectroscopic evidence, clusters were attached datively to the surface, and the integrity of the [CoPW11] cluster was maintained for nonaqueous impregnation with TBA5[CoPW11]; partial degradation of the cluster occurred when it was impregnated from aqueous solution using the K5[CoPW11] salt. Both the amine surface groups and the cobalt centers in the clusters were found to be necessary to prevent cluster loss during washing or reaction processes. The catalytic activities of the supported TMSP clusters were tested by the epoxidation of cyclohexene to cyclohexene oxide in the presence of isobutyraldehyde. The percent conversion of the substrate and the amount of product formed per unit time were similar for [CoPW11] clusters on each of the three silica supports, but slightly lower than for purely homogeneous reactions. [SiW9Co3] clusters with three available cobalt centers exhibited higher catalytic activity with nearly identical performance on a silica support or in homogeneous solution.

The role of human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in the detection of cervical intraepithelial neoplasia among human immunodeficiency virus-infected women. Cervical Disease Study Group of the American Foundation for AIDS Research Community Based Clinical Trials Network

OBJECTIVES

We sought to measure the characteristics of a quantitative human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in screening for cervical intraepithelial neoplasia among human immunodeficiency virus-infected women.

STUDY DESIGN

Human immunodeficiency virus-infected women with screening CD4+ lymphocyte counts of < or = 500 cells/mm3 (n = 103) were examined by quantitative human papillomavirus deoxyribonucleic acid assay and serial cervical cytologic examination and by colposcopy with biopsy and endocervical curettage during the course of 1 year.

RESULTS

Quantitative measures of total human papillomavirus deoxyribonucleic acid and high-risk human papillomavirus deoxyribonucleic acid were strongly associated with any cervical intraepithelial neoplasia (P = .005) and high-grade cervical intraepithelial neoplasia (P = .0006), but they improved the sensitivity and negative predictive value of baseline screening only slightly when combined with cervical cytologic examination. Incident cervical intraepithelial neoplasia occurred frequently (20%) during 1 year of follow-up and was more common among human papillomavirus-infected women. Repeated cytologic examination identified 60% of women with new cervical intraepithelial neoplasia.

CONCLUSION

Human immunodeficiency virus-infected women with at least mild immunosuppression have a high incidence of cervical intraepithelial neoplasia, which warrants close follow-up. Those with high baseline human papillomavirus deoxyribonucleic acid levels may be at the highest risk for incident cervical intraepithelial neoplasia.

Serological detection of cutaneous T-cell lymphoma-associated antigens

Cutaneous T-cell lymphomas (CTCL) are a group of skin neoplasms that originate from T lymphocytes and are difficult to treat in advanced stages. The present study is aimed at the identification of tumor-specific antigens from a human testis cDNA library using human sera known as the SEREX (serological identification of recombinantly expressed genes) approach. A cDNA library from normal testicle tissue was prepared and approximately 2 million recombinants were screened with sera from Sézary Syndrome and Mycosis fungoides patients. A total of 28 positive clones belonging to 15 different genes/ORFs were identified, including five hitherto unknown sequences. Whereas control sera did not react with most clones, 11-71% sera from CTCL patients were reactive against the identified clones. Expression analysis on 28 normal control and 17 CTCL tissues by reverse transcription-PCR (RT-PCR) and Northern blotting revealed seven ubiquitously distributed antigens, six differentially expressed antigens (several normal tissues were positive), and two tumor-specific antigens that were expressed only in testis and tumor tissues: (i) A SCP-1-like sequence, which has already been detected in various tumors, has been found in one CTCL tumor and four sera of CTCL patients reacted with various SCP-1-like clones and (ii) a new sequence named cTAGE-1 (CTCL-associated antigen 1) was detected in 35% of CTCL tumor tissues and sera of 6/18 patients reacted with this clone. The present study unravels CTCL-associated antigens independent of the T-cell receptor. The SCP-1-like gene and cTAGE-1 were shown to be immunogenic and immunologically tumor-specific and may therefore be candidates for immunotherapy targeting CTCL.

Solid cancers after bone marrow transplantation

PURPOSE

To evaluate the incidence and associated risk factors of solid cancers after bone marrow transplantation (BMT).

PATIENTS AND METHODS

We analyzed 2,129 patients who had undergone BMT for hematologic malignancies at the City of Hope National Medical Center between 1976 and 1998. A retrospective cohort and nested case-control study design were used to evaluate the role of pretransplantation therapeutic exposures and transplant conditioning regimens.

RESULTS

Twenty-nine patients developed solid cancers after BMT, which represents a two-fold increase in risk compared with a comparable normal population. The estimated cumulative probability (+/- SE) for development of a solid cancer was 6.1% +/- 1.6% at 10 years. The risk was significantly elevated for liver cancer (standardized incidence ratio [SIR], 27.7; 95% confidence interval [CI], 1.9 to 57.3), cancer of the oral cavity (SIR, 17.4; 95% CI, 6.3 to 34.1), and cervical cancer (SIR, 13.3; 95% CI, 3.5 to 29.6). Each of the two patients with liver cancer had a history of chronic hepatitis C infection. All six patients with squamous cell carcinoma of the skin had chronic graft-versus-host disease. The risk was significantly higher for survivors who were younger than 34 years of age at time of BMT (SIR, 5.3; 95% CI, 2.7 to 8.6). Cancers of the thyroid gland, liver, and oral cavity occurred primarily among patients who received total-body irradiation.

CONCLUSION

The risk of radiation-associated solid tumor development after BMT is likely to increase with longer follow-up. This underscores the importance of close monitoring of patients who undergo BMT.

[Screening for early detection of prostate cancer (first experience in Israel)]

Prostatic cancer (PC) is second only to lung cancer as a cause of cancer mortality in men word-wide. In Israel it is the most common cause of cancer mortality in men, after lung cancer and colo-rectal cancer. We screened, for the first time in Israel, for prostatic cancer using serum levels of PSA and a digital rectal examination (DRE). The purpose was not only to diagnose PC but also to increase public awareness of the condition. 300 men in the Haifa area who met statistical criteria for early diagnosis of PC participated. They filled a questionnaire regarding risk factors for PC (age, family history (FH) of prostatic and breast cancer, cigarette smoking, alcohol consumption, previous PSA sampling) and were examined. Those who had out-of-range, age-related PSA values, or a pathologic DRE underwent trans-rectal ultrasound (TRUS) examination and guided biopsy of the prostate. Those with a positive biopsy for PC underwent radical prostatectomy or radiation therapy. 41 (14.3%) had out-of-range, age-related PSA levels and 10 (3.5%) had a pathologic DRE. 39 (13.3%) underwent TRUS and biopsy and 6 (2.04%) had clinically significant PC, all early stages (Gleason 4-6). Correlation between age and PSA has been proven statistically significant (p < 0.05). Symptoms of urinary tract obstruction and nocturia were related to a high PSA (p = 0.035 and 0.002, respectively). Those with PC had at least 1 symptom of urinary tract obstruction; 6 (15.3%) who underwent TRUS and biopsy and a FH of prostate cancer. However, no subject with a FH of PC had biopsy-proven cancer. Those with PC had PSA values from 4.9 to 31.8 ng/ml (9.6 median). Age-related PSA had a positive predictive value of 17.1%. Results of our annual screening for early detection of PC using age-related PSA, and DRE are encouraging: cases detected were clinically significant and treatable. It would appear that screening for PC will result in decreasing the incidence of metastatic cancer and therefore mortality.

Are infant behavioural feeding difficulties associated with congenital heart disease?

AIM

To compare the feeding patterns and difficulties of infants with congenital heart disease (CHD) and healthy controls. Information was gathered via parental questionnaires.

METHODS

A matched case controlled study of 64 infants with CHD compared with 64 healthy controls.

RESULTS

The main findings were: (1) Feeding patterns: mothers with infants with CHD used bottle-feeding as a first method of feeding their babies more often (CHD, 20%, controls, 2%); (2) Specific feeding difficulties: (a) infants with CHD were significantly more breathless when feeding (CHD = 16%, controls, 0%), (b) had more vomiting at mealtimes (CHD = 23%, controls = 11%), but (c) had significantly less spitting (CHD = 19%, controls, 41%); and (3) infants with CHD showed significantly reduced growth.

CONCLUSIONS

The feeding difficulties are related to the organic condition and not specific difficulties in mother-infant interaction. Professional support may be required for mothers of infants with CHD to maintain feeding routines and to deal with the difficulties that arise.

Qualitative interview study of communication between parents and children about maternal breast cancer

OBJECTIVE

To examine parents' communication with their children about the diagnosis and initial treatment of breast cancer in the mother.

DESIGN

Qualitative interview study within a cross-sectional cohort.

SETTING

Two breast cancer treatment centers.

PARTICIPANTS

32 women with stage I or stage II breast cancer with 56 school-aged children. Main outcome measures Semistructured interview regarding timing and extent of communication with children about the diagnosis and initial treatment of the mother's illness, reasons for talking to children or withholding information, and help available and requested from health professionals.

RESULTS

Women were most likely to begin talking to their children after their diagnosis had been confirmed by biopsy, but a few waited until after surgery or said nothing at all. Family discussion did not necessarily include mention of cancer. There was considerable consistency in the reasons given for either discussing or not discussing the diagnosis. The most common reason for not communicating was to avoid children's questions, particularly those about death. Although most women had helpful discussion with a physician concerning their illness, few were offered help with talking to their children; many would have liked help, particularly the opportunity for both parents to talk to a health professional with experience in understanding and talking to children.

CONCLUSION

Parents diagnosed with cancer or other serious illnesses should be offered help to think about whether, what, and how to tell their children and about what children can understand, especially as they may well be struggling themselves to come to terms with their illness.

Field research for the authorisation of pesticides

On request of the Dutch government a committee of the Health Council of the Netherlands has reviewed the role that results of field research in its broadest sense (i.e., including multi-species toxicity tests in the laboratory, research on model ecosystems et cetera) can play in ecotoxicological risk assessment for the authorisation of pesticides. The Committee believes that field research can provide valuable additional data about the exposure of non-target organisms and the resultant effects at population, community and ecosystem level. However, it frequently is unclear how these data might be used in reaching a decision about authorisation. To solve this problem, it is necessary to specify what is understood by "unacceptable damage". Both more clearly formulated protection goals of the government and a better understanding of the ecological significance of effects are needed to clarify this. Furthermore, the Committee points out that the statistical power of field trials must be sufficient to allow for the detection of changes that might be regarded as ecologically relevant. Finally, it recommends keeping a finger on the pulse in relation to authorised pesticides by monitoring their presence in environmental compartments and by investigating their role in suddenly occurring mortality among conspicuous animal species, such as birds, fish and honeybees. This kind of research forms a safety net for substances that have been wrongly authorised.