A Comparison of Chronic Pain Prevalence in Japan, Thailand, and Myanmar

Background: Pain has been regarded as important in the improvement of quality of life (QOL). In the advanced countries of Europe and the North America, a number of large-scale epidemiological surveys on pain, particularly chronic pain, have thus been performed in general populations. However, few epidemiological surveys of chronic pain have been reported from developing countries, and no surveys appear to have examined chronic pain in the least developed countries. Objectives: To compare the incidence of chronic pain in Asian countries, using Japan as an advanced country, Thailand as a developing country, and Myanmar as one of the least developed countries. Study Design: Cross-sectional study in 4 hospitals. Setting: A university hospital and a general hospital in Japan, a university hospital in Thailand, and a general hospital in Myanmar. Methods: Patients were 1,000 nursing staff working in Japan, 448 nursing staff working in Thailand, and 405 nursing staff working in Myanmar. The survey was performed by requesting all nursing staff to anonymously answer the questionnaire. Data were used to calculate chronic pain prevalence, pain site, presence or absence of consultation with doctors, methods of handling pain other than consultation with doctors, and whether pain was controlled for each country. The results were then compared between countries. Results: The prevalence of chronic pain in Myanmar was 5.9%, which was significantly lower (P < 0.01) than in Japan (17.5%) or Thailand (19.9%). The most frequent pain sites were the lower back, head, and shoulders in Japan, and the shoulders, ankle, upper back, and head in Thailand, whereas in Myanmar, no clear certain tendencies were observed. The most frequent method for handling pain other than consultation with doctors was over-the-counter drugs in Japan, massage in Thailand, and relaxation therapy (meditation) in Myanmar. Limitations: Limitations of this study were the cross-sectional design study, the small number of hospitals included, the limitation of patients to nursing staff, and the omission from the questionnaire of questions regarding body height and weight, working situation, family background, trauma history, sports activity history, smoking history, psychological/character tests, QOL, and pain levels of patients. Conclusion: The prevalence of chronic pain was significantly lower in Myanmar than in Japan or Thailand. With regard to the site and treatment of chronic pain, no clear tendencies were observed between countries, suggesting that frequency and the character of chronic pain differ from county to country around the world. Key words: Chronic pain, epidemiology, prevalence, low back pain, shoulder pain, ankle pain, headache, developing countries, least developed countries

A comparison of chronic pain prevalence in Japan, Thailand, and myanmar

BACKGROUND

Pain has been regarded as important in the improvement of quality of life (QOL). In the advanced countries of Europe and the North America, a number of large-scale epidemiological surveys on pain, particularly chronic pain, have thus been performed in general populations. However, few epidemiological surveys of chronic pain have been reported from developing countries, and no surveys appear to have examined chronic pain in the least developed countries.

OBJECTIVES

To compare the incidence of chronic pain in Asian countries, using Japan as an advanced country, Thailand as a developing country, and Myanmar as one of the least developed countries.

STUDY DESIGN

Cross-sectional study in 4 hospitals.

SETTING

A university hospital and a general hospital in Japan, a university hospital in Thailand, and a general hospital in Myanmar.

METHODS

Patients were 1,000 nursing staff working in Japan, 448 nursing staff working in Thailand, and 405 nursing staff working in Myanmar. The survey was performed by requesting all nursing staff to anonymously answer the questionnaire. Data were used to calculate chronic pain prevalence, pain site, presence or absence of consultation with doctors, methods of handling pain other than consultation with doctors, and whether pain was controlled for each country. The results were then compared between countries.

RESULTS

The prevalence of chronic pain in Myanmar was 5.9%, which was significantly lower (P < 0.01) than in Japan (17.5%) or Thailand (19.9%). The most frequent pain sites were the lower back, head, and shoulders in Japan, and the shoulders, ankle, upper back, and head in Thailand, whereas in Myanmar, no clear certain tendencies were observed. The most frequent method for handling pain other than consultation with doctors was over-the-counter drugs in Japan, massage in Thailand, and relaxation therapy (meditation) in Myanmar.

LIMITATIONS

Limitations of this study were the cross-sectional design study, the small number of hospitals included, the limitation of patients to nursing staff, and the omission from the questionnaire of questions regarding body height and weight, working situation, family background, trauma history, sports activity history, smoking history, psychological/character tests, QOL, and pain levels of patients.

CONCLUSION

The prevalence of chronic pain was significantly lower in Myanmar than in Japan or Thailand. With regard to the site and treatment of chronic pain, no clear tendencies were observed between countries, suggesting that frequency and the character of chronic pain differ from country to country around the world.

Development of an (e,2e) electron momentum spectroscopy apparatus using an ultrashort pulsed electron gun

An (e,2e) apparatus for electron momentum spectroscopy (EMS) has been developed, which employs an ultrashort-pulsed incident electron beam with a repetition rate of 5 kHz and a pulse duration in the order of a picosecond. Its instrumental design and technical details are reported, involving demonstration of a new method for finding time-zero. Furthermore, EMS data for the neutral Ne atom in the ground state measured by using the pulsed electron beam are presented to illustrate the potential abilities of the apparatus for ultrafast molecular dynamics, such as by combining EMS with the pump-and-probe technique.

Congenital absence of the lumbar facet joint associated with bilateral spondylolysis of the fifth lumbar vertebra

A 14-year-old boy presented with a rare case of congenital absence of lumbar facet joint manifesting as low back pain. Physical examination showed no neurological or hematologic abnormalities. Radiography revealed absence of a facet joint on the right side of L4-5. Computed tomography and three-dimensional computed tomography revealed absence of the facet joint on the right side of L4-5 and spondylolysis on both sides of L5. Pain subsided after conservative treatment. This is an extremely rare case of congenital absence of lumbar facet joint associated with bilateral spondylolysis.

Effect of autologous platelet-rich plasma-releasate on intervertebral disc degeneration in the rabbit anular puncture model: a preclinical study

INTRODUCTION

Platelet-rich plasma (PRP) is a fraction of plasma in which several growth factors are concentrated at high levels. The active soluble releasate isolated following platelet activation of PRP (PRP-releasate) has been demonstrated to stimulate the metabolism of IVD cells in vitro. The in vivo effect of PRP-releasate on degenerated IVD remains unknown. The purpose of this study was to determine the reparative effects of autologous PRP-releasate on degenerated intervertebral discs (IVDs).

METHODS

To induce disc degeneration, New Zealand white rabbits (n = 12) received anular puncture in two noncontiguous discs. Autologous PRP and PPP (platelet-poor plasma) were isolated from fresh blood using two centrifugation techniques. Four weeks after the initial puncture, releasate isolated from clotted PPP or PRP (PPP- or PRP-releasate), or phosphate-buffered saline (PBS; control) was injected into the punctured discs. Disc height, magnetic resonance imaging (MRI) T2-mapping and histology were assessed.

RESULTS

Anular puncture produced a consistent disc narrowing within four weeks. PRP-releasate induced a statistically significant restoration of disc height (PRP vs. PPP and PBS, P<0.05). In T2-quantification, the mean T2-values of the nucleus pulposus (NP) and anulus fibrosus (AF) of the discs were not significantly different among the three treatment groups. Histologically, the number of chondrocyte-like cells was significantly higher in the discs injected with PRP-releasate compared to that with PBS.

CONCLUSIONS

The administration of active PRP-releasate induced a reparative effect on rabbit degenerated IVDs. The results of this study suggest that the use of autologous PRP-releasate is safe and can lead to a clinical application for IVD degeneration.

Does going to an amusement park alleviate low back pain? A preliminary study

Background

Low back pain is often called nonspecific pain. In this type of low back pain, various emotions and stress are known to strongly affect pain perception. The purpose of this study is to investigate how the degree of low back pain changes in people with chronic mild low back pain when they are inside and outside of an amusement park where people are supposed to have physical and psychological enjoyment.

Methods

The subjects were 23 volunteers (13 males and 10 females) aged 18 to 46 years old with a mean age of 24.0 years who had chronic low back pain. Visual analog scale (VAS) scores of low back pain and salivary amylase levels (kIU/L) of all subjects were measured at five time points: immediately after getting on the bus heading for the amusement park; 10 minutes, 1 hour (immediately after boarding the roller coaster), and 3 hours (immediately after exiting the haunted house) after arriving at the amusement park; and immediately before getting off the bus returning from the park.

Results

The three VAS values in the amusement park (10 minutes, 1 hour, and 3 hours after arriving at the amusement park) measured were significantly lower (P < 0.05) when compared with the other two values measured immediately after getting on the bus heading for the amusement park and immediately before getting off the return bus. In salivary amylase levels, there were no statistically significant differences among the values measured at the five time points.

Conclusion

Low back pain was significantly alleviated when the subjects were in the amusement park, which demonstrated that enjoyable activities, though temporarily, alleviated their low back pain.

Personality of outpatients with malignant tumors: a cross-sectional study

Background

There have been scarce large-scale studies investigating the personality of patients with malignant tumors. The purpose of this study is to determine the characteristic personality in malignant tumors outpatients.

Methods

Three thousand and three among 5013 consecutive outpatients who consented to answer the Japanese Maudsley Personality Inventory questionnaires were divided into two groups. 603 outpatients diagnosed with malignant tumors (M group) and the other 2400 outpatients (non-M group) were enrolled in this study. We determined three scores such as introversion/extroversion (E-score), neuroticism (N-score), and lie detection (L-score). All data were used to compare the two groups.

Results

Average E-score was slightly higher, and average N-score was slightly lower in M group than that in non-M group, and no significant differences between the two groups. However, the average L-score in M group was significant higher than that in non-M group (p < 0.01).

Conclusion

Outpatients with malignant tumors showed a significantly higher L-score on MPI when compared with patients with non-malignant tumors. These results stress the importance of taking the mentality of patients with cancer into consideration when conducting treatment and care.

Ultrasonic measurement of bone thickness for spinal surgery

We measured the thickness of the transverse structures associated with the bovine coccygeal transverse processes (bone specimen) by using ultrasonic waves and examined the reliability of this measurement for use in spinal surgery. We first measured the velocity of ultrasonic waves propagating in the spinous process. We then made a hole in the transverse process with an air drill and placed an ultrasonic transducer with a center frequency of 10 MHz in the hole. The time of reflection of the ultrasonic wave from the underside of the transverse process was detected to estimate the remaining bone thickness. The thickness estimated by using ultrasound was compared with the thickness measured by microscopic examination. We could detect reflection waves from the underside of the transverse process in 91.7% of cases (i.e., 22 of 24 measurements using 6 bones from 3 cows). The thickness of the transverse processes in which we detected the waves varied from 0.24 to 6.8 mm. The 95% limit of agreement between ultrasonic and histological measurement was 0.71 mm. Pearson's correlation coefficient showed a strong and positive relationship between the two measurements (r = 0.97, n = 22, P <0.0001).

Basic research on a cylindrical implant made of shape-memory alloy for the treatment of long bone fracture

The internal fixing materials made from shape-memory alloys (SMAs) have recently been reported for long bone fracture. We present a new internal fixation technique using a cylindrical SMAs implant in a rat femoral fracture healing. The implant was designed in a shape to circumferentially fix the fractured bone using resilient SMA claws. To evaluate the fixing ability of the implant, three-point bending and rotation tests were performed. Fifteen female Wister rats were treated surgically as an experimental model. All rats were killed at 16 weeks postoperatively, and the radiological and histological evaluations were performed. In biomechanical test, the good fixation ability of the implant was demonstrated. In animal model, no cases of postoperative infection or death were encountered and postoperative gait was stable in all cases. Radiological examination at 16 weeks postoperatively demonstrated the implant firmly fixed to the fractured part, endosteal healing, and no callus formation in all cases. In Histological evaluation, bone union in all cases was characterized by endochondral ossification from within the medullary cavity. In conclusion, our cylindrical SMA implant provided good fixation in biomechanical tests, and achieved bone union in all 15 rats. If a larger size is designed in the future, our implant will be a clinically applicable, useful fixing material for fracture of the human long bones.

Giant pseudomeningocele after spinal surgery: A case report

Very few reports have described giant pseudomeningoceles ≥ 8 cm in diameter. We report this case of the biggest giant pseudomeningocele at the unusual cervicothoracic level. A 59 year old man who underwent cervicothoracic laminectomy had a giant pseudomeningocele detected and the lesion gradually grew to about 15 cm in diameter by 2 years postoperatively. Cerebrospinal fluid leak closure was performed and the postoperative course was favorable. We present this case, review the literature and discuss the size and portion, mechanism of formation, symptoms and treatments of giant pseudomeningocele.

Note: wearable near-infrared spectroscopy imager for haired region

A wearable optical topography system was developed that is based on near-infrared spectroscopy (NIRS) for observing brain activity noninvasively including in regions covered by hair. An avalanche photo diode, high voltage dc-dc converter, and preamplifier were placed in an electrically shielded case to be safely mounted on the head. Rubber teeth and a glass rod were prepared to clear away hair and reach the scalp. These devices realized for the first time a wearable NIRS imager for any region of the cortex. The activity in the motor cortex during finger tapping was successfully observed.

Magnetic resonance imaging findings of remnants of an intradural oil-based contrast agent: report of a case

BACKGROUND

Myodil (iophendylate), an oil-based positive contrast media, now discontinued, was widely used for performing myelography 30-70 years ago. We identified this agent as the explanation for uncommon magnetic resonance imaging (MRI) findings in a patient with thoracic spinal fracture.

DESIGN

Case report and literature review.

FINDINGS

An 81-year-old man complained of back pain after falling down stairs. Anamnesis revealed that he had undergone myelography with an oil-based contrast agent about 60 years previously as a part of the diagnostic workup for back pain and sudden onset of gait difficulty. Plain radiography of the thoraco-lumbar spine showed a fracture of the eleventh thoracic vertebra and a radio-opaque, oval shadow at the level of the T9-T10 vertebrae. Many small radio-opaque dots with the appearance of a string of pearls were seen from T8 to L3 vertebrae. MRI revealed a sharply demarcated intradural extramedullary mass, of approximately 5 mm in diameter on the left side of the dura in the region of the T9-T10. The mass showed high signal intensity on T1-weighted MRI, and low signal intensity on T2-weighted MRI.

CONCLUSIONS

Increased awareness of this rare presentation of procedures performed in the past is essential when atypical radiographic images are encountered. This case illustrates rare sequelae of Myodil use manifesting decades after administration.

Relationship between brassiere cup size and shoulder-neck pain in women

There are very few reports in regard to relationship between breast size and shoulder-neck pain. The purpose of this study is to examine the correlations among breast size, brassiere cup size, and moment-in-time reporting of shoulderneck pain in a group of adult women. Three hundred thirty nine female volunteers from the hospital staff answered the questionnaire. Breast size, brassiere cup size, and shoulder-neck pain were self-reported by each participant. The relationship among breast size, brassiere cup size and shoulder-neck pain was investigated. Spearman's test showed no significant relationship between shoulder-neck pain and brassiere cup size. However, after participants were classified into two groups (small brassiere cup size and large brassiere cup size with 219 and 120 participants, respectively), there was a significant positive correlation between shoulder-neck pain and large brassiere cup size (p<0.05). There was no significant relationship between shoulder-neck pain and breast size. In conclusion, large brassiere cup size is an important cause of shoulder-neck pain.

Increasing tamoxifen dose in breast cancer patients based on CYP2D6 genotypes and endoxifen levels: effect on active metabolite isomers and the antiestrogenic activity score

Tamoxifen (Tam), the major drug for estrogen receptor (ER)-positive breast cancer, is converted to its active metabolites, Z- and Z'-endoxifen and 4-OH-Tam isomers, primarily by cytochrome P450 CYP2D6. In 117 patients taking 20 mg/day of Tam, we determined CYP2D6 genotypes and measured the plasma levels of Tam metabolites. The Z-endoxifen levels increased while Z'-endoxifen levels decreased with increasing metabolizer phenotype activity (MPA) score (P ≤ 0.0004). The dosage in patients with endoxifen <40 nmol/l and/or CYP2D6 MPA scores of 0 was increased to 30 mg/day and their metabolite isomers were monitored for up to 90 days. Of the 24 patients on the increased dose, 90% showed an increase in active isomers by day 60; the rate of increase correlated with the MPA score. Notably, their antiestrogenic activity scores (AASs), which estimate total isomer biologic activity, increased from a baseline median of 17 to 26 at day 60. Further studies involving increasing/decreasing the Tam dosage based on the AAS may determine whether dose adjustment can optimize treatment and improve long-term survival.

Identification of CYP2C19*4B: pharmacogenetic implications for drug metabolism including clopidogrel responsiveness

CYP2C19 is a principal enzyme involved in the bioactivation of the antiplatelet prodrug clopidogrel and common CYP2C19 loss-of-function alleles are associated with adverse cardiovascular events. To assess the impact of the CYP2C19*17 increased activity allele in the Ashkenazi Jewish (AJ) and Sephardi Jewish (SJ) populations and to determine the frequencies of additional variant alleles, 250 AJ and 135 SJ individuals were genotyped for CYP2C19*2-*10, *12-*17, *22 and P-glycoprotein (ABCB1) c.3435C>T. Importantly, CYP2C19*4, a loss-of-function allele, was identified in linkage disequilibrium with *17. This novel haplotype, designated CYP2C19*4B, significantly alters the interpretation of CYP2C19 genotyping when testing *17. Moreover, genotyping CYP2C19*17 changed the frequency of extensive metabolizers from ∼70 to ∼40%, reclassifying ∼30% as ultrarapid metabolizers. Combining CYP2C19 and ABCB1 identified ∼1 in 3 AJ and ∼1 in 2 SJ individuals at increased risk for adverse responses to clopidogrel. These data underscore the importance of including *4B and *17 when clinically genotyping CYP2C19.

Abstract P4-02-06: Beyond CYP2D6 Genotyping: Personalized Dosing of Tamoxifen (Tam) Based on Low Serum Endoxifen Levels

Background: The efficacy of Tam varies widely. Tam is biotransformed to endoxifen and 4-OH-Tam by the cytochrome P450 2D6 enzymes. Studies on 2D6 variants as a predictor of Tam's efficacy show conflicting results. Compared to Tam, endoxifen and 4-OH-Tam have a 100-fold greater affinity for the estrogen receptor (ER) and in suppressing estrogen-dependent cell proliferation. However, endoxifen is present at concentrations up to 20-fold higher and is pharmacologically distinct from 4-OH-Tam. Endoxifen's effect on ERα-degredation and transcription is concentration dependent; serum endoxifen levels ≥40nM block ERα-mediated transcriptional activation and inhibit estrogen-induced breast cancer cell proliferation.

Methods: Pts taking Tam 20 mg/day, for any reason, were potentially eligible. Serum Tam, Tam metabolites and nineteen 2D6 alleles were analyzed. 2D6 genotyping was performed by PCR-based procedures and metabolites were assessed on Liquid Chromatography/Tandem Mass Spectrometry. Pts were stratified by 2D6 function into 3 groups: extensive metabolizers (EM) who had normal enzyme activity; intermediate metabolizers (IM) who had reduced enzyme activity; and poor metabolizers (PM) who had no enzyme activity. Tam was increased to 30 mg/day if serum endoxifen &lt; 40nMol. Serum Tam and Tam metabolites were measured every 2 weeks for 90 days.

Results: 121 patients have enrolled to date. Age, ethnicity, BMI, concomitant medications, and adherence were recorded. 25/117 (21%) pts had low serum endoxifen; all of these pts were increased to Tam 30 mg/day. Of this cohort, 36% were PMs (PM/PM and PM/IM), 32% were IMs (EM/PM and IM/IM) and 32% were EMs (EM/EM and EM/IM). All patients’ serum endoxifen increased to &gt;40nMol by day 30 (Diagram below).

Conclusions: 1) Sub-therapeutic serum endoxifen can be found in any 2D6 phenotype. 2) It is possible to achieve therapeutic serum endoxifen/Tam metabolite levels by optimizing the dose of Tam. 3) Subsequently, it is likely that other gene variants are involved in Tam metabolism hence why 2D6 testing may lead to conflicting results. 4). Further investigation is warranted as personalizing the dose of Tam is feasible and may potentially improve the outcome of pts taking Tam regardless of 2D6 genotype. Figure available in online version.

Percutaneous vertebroplasty for osteoporotic compression fractures using calcium phosphate cement

PURPOSE

To compare percutaneous transpedicular vertebroplasty using calcium phosphate cement (CPC) versus conservative treatment for osteoporotic vertebral fractures.

METHODS

Eight men and 28 women aged 61 to 99 (mean, 80) years with osteoporotic vertebral fractures underwent percutaneous transpedicular vertebroplasty using CPC. During the same period, 6 men and 32 women aged 53 to 93 (mean, 77) years underwent conservative treatment. The indication for vertebroplasty was a painful unstable fracture, with mobility of the vertebral body shown on flexion and extension lateral radiographs. Fractures without mobility despite deformity were treated conservatively.

RESULTS

In the vertebroplasty group, all patients benefited from reduced back pain immediately after surgery, and pain relief was maintained at the latest follow-up. However, correction loss continued until one month after the operation. The mean visual analogue score for pain decreased significantly from preoperation to one day after surgery (9.3 vs. 6.2, p=0.02), and further decreased to 2.8 (p = 0.04) on day 3 or 4 when ambulation began, and to 1.5 at the one month follow-up and 1.4 at the final follow-up (mean, 14 months). The mean duration of analgesic treatment was significantly shorter in the vertebroplasty than conservatively treated group (10.2 vs. 63.5 days). All patients in the vertebroplasty group achieved bone union, with no adjacent vertebral fractures. However, in patients having conservative treatment, there were 2 adjacent vertebral fractures and 4 pseudarthroses, and the collapse continued for several months.

CONCLUSION

Percutaneous transpedicular vertebroplasty using CPC achieves immediate pain relief and reduces the risk of vertebral body collapse and pseudarthrosis among elderly patients with osteoporotic vertebral compression fractures.

Biomechanical study of the lumbar spine using a unilateral pedicle screw fixation system

Lumbar fusion combined with unilateral pedicle screw fixation has received favourable clinical reports. However, there are very few reports about the biomechanical properties of this system. The purpose of this study was to compare the biomechanics of a unilateral pedicle screw system with a bilateral system. Two fresh lumbar vertebral columns from human cadavers were used. Seven models were prepared by the sequential damage and spinal instrumentation of each specimen. Bending and rotation tests were performed to clarify the range of motion for each model using a 6-axis material tester that we have developed. We showed that the unilateral pedicle screw system offers only uneven fixation. This results in dispersion of rigidity depending on the direction of bending and rotation. The bilateral pedicle screw system, however, allows excellent fixation in all directions.

Low back pain and cervical spondylotic myelopathy

PURPOSE

To determine characteristics responsible for improvement of low back pain after cervical laminoplasty for cervical spondylotic myelopathy.

METHODS

18 men and 10 women aged 38 to 88 (mean, 71) years who had a low back pain visual analogue scale (VAS) score of 5 or more before cervical laminoplasty were included. In 12 patients the VAS score improved to 1 or <1 after surgery and remained so at 2 years, but in 16 it remained unimproved. Patient characteristics of the 2 groups were compared.

RESULTS

Preoperatively, 11 of the 12 patients with improved VAS score had continuous low back pain all day, compared to 3 of the 16 who remained unimproved (p<0.01).

CONCLUSION

In some patients, low back pain may be improved following cervical laminoplasty.

Chronic Effects of Norepinephrine and Vasopressin on Urinary Prostaglandin E and Kallikrein Excretions in Conscious Rats

To assess in vivo functional interactions of vasopressor substances, norepinephrine and vasopressin, with renal prostaglandins and kallikrein-kinin system which are responsible for the vasodepressor mechanism in the kidney, we evaluated chronic effects of norepinephrine (1.8 mg/kg/day ip) and vasopressin (7.2 U/kg/day ip) on urinary prostaglandin E excretion and urinary kallikrein excretion in conscious rats. Both norepinephrine and vasopressin induced a sustained increase in systolic blood pressure. Norepinephrine induced slight but significant increases in urinary prostaglandin E excretion and urinary kallikrein excretion which were sustained for up to 6 days. Vasopressin induced a marked increase in urinary prostaglandin E excretion which was sustained for up to 6 days, whereas it induced a sustained decrease in urinary kallikrein excretion. Circulating angiotensin II levels was not changed by norepinephrine, but was decreased by vasopressin. These results indicate that renal prostaglandin E may not correlate with renal kallikrein-kinin and renin-angiotensin system in the responses to norepinephrine and vasopressin, and that vasopressin may be a more potent stimulator of the synthesis or release of renal prostaglandin E.

Environmental properties of long-chain alcohols. Part 2: Structure-activity relationship for chronic aquatic toxicity of long-chain alcohols

Daphnia magna reproduction tests were performed with C(10), C(12), C(14) and C(15) alcohols to establish a structure-activity relationship of chronic effects of long-chain alcohols. The data generation involved substantial methodological efforts due to the exceptionally rapid biodegradability of the test substances and the need to test as close as possible to their water solubility limits. Test concentrations were determined by GC-MS before and after test solution renewal. Whereas apparent toxicity based on survival and reproduction increased with increasing C-chain lengths up to C(14), observations of toxicity to C(15) alcohol were not in line with lower chain lengths due to the lack of toxicity below the level of water solubility. When omitting C(15), the slope of most (Q)SARs approach -1, being consistent with the expectation of a non-polar narcotic mode of action. Further testing at higher chain lengths is not sensible due to progressively lower solubility, at remaining biodegradability. Effects on mortality and reproduction are not expected below the level of water solubility.