Heart Rate Extraction in a Headphone Using Infrared Thermometry.

The heart rate is a vital indicator of the health state of an individual. By continuously monitoring it, the fitness and health of the cardiovascular system of a user can be analyzed and impending problematic health episodes could be addressed better. Existing techniques to measure heart rate, such as electrocardiogram or photoplethysmography, are either uncomfortable for the user, or are not low-power or sensitive to motion artifacts. Infrared thermography is a non-contact technique with improved user comfort and low power consumption. In this paper, we have analyzed, built, and tested a novel system that uses infrared differential thermometry to detect the heart rate in the auricle. The sensor system was fitted into a commercial headphone since this paper is a first step into integration of the system in a Bluetooth headset. To the best of our knowledge, there has been no previous work on the detection of the heart rate signal in the ear using infrared thermometry. Positive results have been obtained after extraction of the frequency features of the bioheat transfer signal on test persons in rest.

Estimates of live birth prevalence of children with Down syndrome in the period 1991-2015 in the Netherlands.

BACKGROUND: In Western countries, increasing maternal age has led to more pregnancies with a child with Down syndrome (DS). However, prenatal screening programs, diagnostic testing and termination of pregnancy influence the actual DS live birth (LB) prevalence as well. The aim of this study is to examine these factors in the Netherlands for the period 1991-2015. In our study, we establish a baseline for DS LB prevalence before non-invasive prenatal testing will be made available to all pregnant women in the Netherlands in 2017. METHODS: Full nationwide data from the Dutch cytogenetic laboratories were used to evaluate the actual DS LB prevalence. In addition, nonselective DS prevalence, which is the DS LB prevalence that would be expected in absence of termination of pregnancies, was estimated on the basis of maternal age distribution in the general population. RESULTS: Because of an increase in maternal age, nonselective DS prevalence increased from around 15.6 [95% confidence interval (CI) 13.9-17.4] per 10 000 LBs in 1991 (311 children in total) to around 22.6 (95% CI 20.3-24.9) per 10 000 in 2015 (385), the increase levelling off in recent years. Actual LB prevalence rose from around 11.6 (95% CI 10.9-12.2) per 10 000 in 1991 (230 children) to an estimated peak of 15.9 (95% CI 15.6-16.2) per 10 000 in 2002 (322), gradually decreasing since to 11.1 (95% CI 10.8-11.5) per 10 000 in 2015 (190). Reduction of DS LBs resulting from elective terminations had been fairly constant between 1995 and 2002 at around 28% and rose afterwards from 35% in 2003 to around 50% in 2015. CONCLUSIONS: In spite of expansion of antenatal screening in the Netherlands in the 1990s and early 2000s, actual DS LB prevalence increased during this period. However, after 2002, this trend reversed, probably because of informing all pregnant women about prenatal testing since 2004 and the implementation of a national screening program in 2007.

A quantitative assessment of educational integration of students with Down syndrome in the Netherlands.

BACKGROUND: In the Netherlands, as in many other countries, there are indications of an inclusive school policy for children with Down syndrome. However, there is a lack of studies that evaluate to what extent this policy has actually succeeded in supporting the mainstreaming of these students. METHOD: For the period 1984-2011, the number of children with Down syndrome entering regular education and the percentage of children still in regular education after 1-7 years were estimated on basis of samples from the database of the Dutch Down Syndrome Foundation. These estimations were combined with historical demographic data on the total number of children with Down syndrome in primary school age. Validity of the model was examined by comparison of the model-based estimations of numbers and percentages in regular education with relevant available empirical data from the Dutch Ministry of Education and from Dutch special schools. RESULTS: The percentage of all children with Down syndrome in the age range 4-13 in regular primary education has risen from 1% or 2% (at the very most about 20 children) in 1986-1987, to 10% (about 140 children) in 1991-1992, to 25% (about 400) in 1996-1997, to 35% (about 650) in 2001-2002 and to 37% (about 800) since 2005-2006. The proportional increase stopped in recent years. CONCLUSION: During the 1980s and 1990s, clearly more and more children with Down syndrome were in regular education, being supported by the then existing ad hoc regulations aimed at providing extra support in regular education. In the Netherlands, in 2003, these temporary regulations were transformed into structural legislation for children with disabilities. With regard to the mainstreaming of students with Down syndrome, the 2003 legislation has consolidated the situation. However, as percentages in regular education stayed fairly constant after 2000, it has failed to boost the mainstreaming of children with Down syndrome. The results of this study are discussed in the context of national and international legislation and educational policy.

The use of a memokath prostatic stent for obstructive voiding symptoms after brachytherapy.

INTRODUCTION: Brachytherapy may be complicated by serious obstructive voiding symptoms (OVS). Only conservative treatment options are available in the first 6 months after brachytherapy. We evaluated safety, efficacy and patient tolerance of the Memokath prostatic stent (MPS). MATERIAL AND METHODS: A MPS was placed in 10 patients with OVS after brachytherapy. Evaluation included uroflowmetry, international prostate symptom score (IPSS), prostate volume and urethrocystoscopy before and 3 months after placement of the stent. RESULTS: Both the IPSS and uroflowmetry results significantly improved after stent insertion. The mean IPSS decreased from 29/5 to 11/1 and the mean Qmax from the uroflowmetry improved from 4.7 to 11.2 ml/s. The 5 patients who were catheter dependent voided spontaneously with a mean Qmax of 15 ml/s. Two stents migrated towards the bladder, and those patients needed a second stent which was placed without complications. Removal of the stent was easy to perform. Adverse effects were minor with perineal pain and irritative voiding symptoms occurring in 5 patients mainly in the first weeks after insertion. This did not negatively influence quality of life and all patients were more satisfied with the stent than without. CONCLUSIONS: The MPS provides a safe, effective, and completely reversible treatment for patients with OVS after brachytherapy and was well tolerated.

More academics in regular schools? The effect of regular versus special school placement on academic skills in Dutch primary school students with Down syndrome.

BACKGROUND: Studies from the UK have shown that children with Down syndrome acquire more academic skills in regular education. Does this likewise hold true for the Dutch situation, even after the effect of selective placement has been taken into account? METHOD: In 2006, an extensive questionnaire was sent to 160 parents of (specially and regularly placed) children with Down syndrome (born 1993-2000) in primary education in the Netherlands with a response rate of 76%. Questions were related to the child's school history, academic and non-academic skills, intelligence quotient, parental educational level, the extent to which parents worked on academics with their child at home, and the amount of academic instructional time at school. Academic skills were predicted with the other variables as independents. RESULTS: For the children in regular schools much more time proved to be spent on academics. Academic performance appeared to be predicted reasonably well on the basis of age, non-academic skills, parental educational level and the extent to which parents worked at home on academics. However, more variance could be predicted when the total amount of years that the child spent in regular education was added, especially regarding reading and to a lesser extent regarding writing and math. In addition, we could prove that this finding could not be accounted for by endogenity. CONCLUSION: Regularly placed children with Down syndrome learn more academics. However, this is not a straight consequence of inclusive placement and age alone, but is also determined by factors such as cognitive functioning, non-academic skills, parental educational level and the extent to which parents worked at home on academics. Nevertheless, it could be proven that the more advanced academic skills of the regularly placed children are not only due to selective placement. The positive effect of regular school on academics appeared to be most pronounced for reading skills.

Changes in yearly birth prevalence rates of children with Down syndrome in the period 1986-2007 in The Netherlands.

BACKGROUND: The Netherlands are lacking reliable national empirical data in relation to the development of birth prevalence of Down syndrome. Our study aims at assessing valid national live birth prevalence rates for the period 1986-2007. METHOD: On the basis of the annual child/adult ratio of Down syndrome diagnoses in five out of the eight Dutch cytogenetic centres, the national annual figures of the National Cytogenetic Network on total numbers of postnatal Down syndrome diagnoses were transformed into national figures on total numbers of postnatal Down syndrome diagnoses in newborn children only. In combination with the national annual data of the Working Group for Prenatal Diagnostics and Therapeutics on numbers of Down syndrome pregnancies not aborted after diagnosis, national figures on birth prevalence were constructed. RESULTS: For the period 1986-2007, results based on the data of the cytogenetic centres are almost similar to the theory-based model data of de Graaf et al., with a small discrepancy of approximately 4%. Down syndrome birth prevalence in the Netherlands shows an upward trend from around 11 per 10,000 births in the early 1990s to around 14 per 10,000 births nowadays. CONCLUSION: In spite of expansion of antenatal screening in the Netherlands, Down syndrome live birth prevalence has risen in the last two decades as a result of rising maternal age. This increase in Down syndrome birth prevalence is in contrast to studies from other European countries.

The role of staging laparoscopy in oesophagogastric cancers.

AIMS: Selection of patients for treatment of oesophagogastric cancers rests on accurate staging. Laparoscopy has become a safe and effective staging tool in upper gastrointestinal cancers because of its ability to detect small peritoneal and liver metastases missed by imaging techniques. The aim of this study was to evaluate the role of staging laparoscopy (SL) in determining resectability of oesophagogastric cancers. METHODS: A review of 511 patients with oesophagogastric cancers referred to our centre during a 7-year period was performed. Four hundred and sixteen of them assessed to have resectable tumours after preoperative staging with CT and/or ultrasound underwent SL. The main outcome measure was the number of patients in whom laparoscopy changed treatment decision. RESULTS: Staging laparoscopy changed treatment decision in 84 cases (20.2%): locally advanced disease in 17, extensive lymph node disease in four and distant metastases (liver and peritoneum) in 63 cases. The sensitivity of laparoscopy for resectability was 88%. Eighty-one percent of patients who had combined CT scan and EUS were resectable at surgery compared with 65% of those who had CT scan alone (statistically significant with P-value<0.05). Of those patients deemed resectable by SL 8.1% were found to be unresectable at laparotomy, 16 with locally advanced disease and 11 with metastases. CONCLUSION: Staging laparoscopy avoided unnecessary laparotomy in 20.2% of our patients and was most useful in adenocarcinoma, distal oesophageal, GOJ and gastric cancers and probably not necessary in lesions of the upper two-third of the oesophagus.

"Everyone dies, so you might as well have fun!" Attitudes of Dutch youths about their health lifestyle.

Most Western societies seem to have embarked on a runaway weight-gain train, equipped with too many accelerators and not enough brakes. Adolescents have been identified as a public health risk group in this area. To uncover youths' attitudes about their health lifestyle, with a focus on overweightness, we conducted a discourse analysis using Q-methodology. Female, Dutch youths between 12 and 15 years rank-ordered statements on issues like eating behaviour, overweightness, health risks, health perceptions and motivations/obstacles for adopting a healthier lifestyle. Q-factor analysis revealed five attitudes: "carefree sporty", "worrying dependent", "contended independent", "looks over content" and "indifferent solitary". The youths were all more or less uninterested in their own health but for different reasons. For most of these youths, neither current nor future health is of major concern, because they feel physically fit, are generally satisfied and happy, or simply do not care. Some are concerned about their eating behaviour due to the consequences it has on appearance, being physically unfit or overweight. Even so, this preoccupation with eating appears far from healthy. Only one of the five health lifestyle attitudes identified combines healthy eating and exercising behaviour. Most youths appear to have little knowledge and many questions regarding health and overweightness.

[Veterinary students' perspective of their professional relationships and responsibilities]. / Het beeld van diergeneeskunde studenten van hun toekomstige patiënten en klanten en professionele verantwoordelijkheid.

Veterinary students were asked their views on their future professional responsibilities as veterinarians, with emphasis on the animal patient-human client-veterinarian relationship. How do veterinary students view their relationship with animal patients and their owners? The article provides discourse descriptions, based on Q-methodology, of first-year and fourth-year students regarding their future professional relationships and responsibilities. The general attitudes of students towards animals, animal welfare, and human clients do not seem to be greatly influenced by attending veterinary school.

[Large animal practitioners' perspective of their patients and clients and their professional responsibilities]. / Het beeld van dierenartsen in de landbouwhuisdierensector van hun patiënten en klanten en hun professionele verantwoordelijkheid.

Veterinarians have obligations towards both the animals they treat and their clients, the owners of the animals. Veterinarians have complicated, and often conflicting, relationships with both groups. In this article, Q-methodology was used as a method for discourse analysis to determine how Dutch large animal practitioners conceptualize animals and their owners and their professional responsibilities towards both. The article focuses on four different perspectives that Dutch veterinarians have of their animal patients and their owners, and of their professional duties and responsibilities.

Effects of atipamezole, detomidine and medetomidine on release of steroid hormones by porcine adrenocortical cells in vitro.

The 4-substituted imidazole type alpha2-adrenoceptor ligands atipamezole, detomidine, and medetomidine were screened for actions on the release of aldosterone by a suspension of porcine adrenocortical cells with deoxycorticosterone (1 microM) as substrate. Progesterone, pregnenolone or corticosterone (all at 1 microM) were also used as substrates. With pregnenolone as substrate, drug-induced effects on the output of nine steroids (aldosterone, corticosterone, cortisol, deoxycortisol, testosterone, progesterone, 17alpha-hydroxyprogesterone, androstenedione, dehydroepiandrosterone) were monitored simultaneously. The alpha2-adrenoceptor antagonist atipamezole was a potent inhibitor of aldosterone release (range 10-1000 nM). The sedative alpha2-adrenoceptor agonists medetomidine and detomidine also inhibited aldosterone release (range 10-1000 nM). With pregnenolone as substrate, the inhibition induced by 4-substituted imidazoles of the release of corticosterone and cortisol was more pronounced than that of aldosterone. Androstenedione and deoxycortisol release was enhanced. The 4-substituted imidazoles atipamezole, detomidine, and medetomidine inhibited mitochondrial cytochrome P450(11beta/18) in vitro. This inhibition was unrelated to their alpha2-adrenoceptor actions. The 4-substituted imidazole type alpha2-adrenoceptor ligands used to control sedation/anaesthesia can alter the steroid-based defence mechanisms of the body.

Effects of alpha1-antagonists on production and release of aldosterone and other steroid hormones by porcine adrenocortical cells in vitro.

Quinazoline type alpha1-adrenoceptor antagonists (range 10-100 microM) inhibited aldosterone release of a cell suspension of porcine adrenocortical cells, potency order: doxazosin > prazosin > trimazosin. Phenoxybenzamine also inhibited the aldosterone release at a concentration of 100 microM. Alpha1-adrenoceptor antagonists from other chemical classes had no measurable effect on the aldosterone output from adrenocortical cells in vitro. Agonists selective for either alpha1- or beta-adrenoceptors did not affect the aldosterone release. The inhibition of the aldosterone release induced by quinazolines was similar with different substrates. The small differences between the drug-induced inhibitions could be ranked as corticosterone = progesterone > pregnenolone = deoxycorticosterone. The doxazosin (10 microM)-induced changes in the release of nine steroids indicated that quinazoline-type alpha1-antagonists interfere with enzymes of the aldosterone biogenesis pathway involved in C18-oxidation and C21beta-hydroxylation, reducing the release of both aldosterone and corticosterone. At higher concentrations (100 microM), the C21beta-hydroxylation in the cortisol biogenesis pathway is also affected, decreasing the output of cortisol and deoxycortisol, but increasing the output of progesterone and OH-progesterone. Simultaneously, the C17-oxidation and side-chain cleavage is also inhibited, decreasing the output of androstenedione. The rank order of phenoxybenzamine (100 microM)-induced inhibition of the aldosterone release with different substrates is pregnenolone > corticosterone = progesterone > deoxycorticosterone. With pregnenolone as substrate, the output of aldosterone, corticosterone, and cortisol was reduced to the same extent. The dehydroepiandrosterone, androstenedione, and progesterone release was enhanced. It seems that phenoxybenzamine is a rather selective inhibitor of the mitochondrial P450(11beta/18) enzymes.

Differential effects of nitrofurans on the production/release of steroid hormones by porcine adrenocortical cells in vitro.

Changes in the biogenesis of corticosteroids caused by nitrofurans were studied. The three nitrofurans used: furazolidone, furaltadone and nitrofurantoin, altered the steroid production/release by porcine adrenocortical cells in vitro during 1 h incubations. With pregnenolone as a substrate the nitrofurans inhibited aldosterone production/release. Although the nitrofurans differed in potency (nitrofurantoin > furazolidone > furaltadone) maximum inhibition occurred at 100 microM. In this concentration the nitrofurans changed also the release/production of other corticosteroids. The output of corticosterone and cortisol decreased by 50%. The production/release of deoxycortisol stayed the same. In contrast the output of progesterone and 17alpha-hydroxyprogesterone increased to more than 200% of control. The nitrofurans slightly reduced the output of androstenedione. No significant increases of the production/release of other steroids (testosterone, dehydroepiandrosterone, estradiol-17beta and estrone) by the cell suspension could be observed. The profile of the nitrofuran-induced changes lead to the conclusion that nitrofurans interfere with mitochondrial enzymes. These enzymes, presumably cytochrome P450(11,18) mediate the hydroxylation and the oxidation at C11 and C18, the final steps in the biogenesis of aldosterone, corticosterone and cortisol. The rapid and reversible fall in the output of these steroids occurs in vitro at concentrations which are below therapeutic blood concentrations seen in vivo. At higher concentrations the nitrofurans hinder the biogenesis of androgens. Thus nitrofurans can also affect steps in the steroid biogenesis located in the endoplasmatic reticulum.

Mild phenotype in interstitial 4p deletion: another patient and review of the literature.

We describe a 7-year-old girl with mild mental retardation and minor dysmorphism. The karyotype was 46,XX,del(4)(p12p15.1). The clinical and cytogenetical findings are compared with 19 previous reported cases of interstitial 4p deletions.

Screening for drug-induced alterations in the production and release of steroid hormones by porcine adrenocortical cells in vitro.

To screen drugs rapidly and at minimal expense for their potential to alter steroidogenesis, an in vitro model using porcine adrenocortical cells was developed. Pregnenolone, progesterone, deoxycorticosterone or corticosterone (all at 1 muM) were used as substrates. Drug-induced changes in the production/release of aldosterone were measured after 1-hr incubation. With pregnenolone, drug-induced effects on the release of nine steroids (aldosterone, corticosterone, cortisol, deoxycortisol, testosterone, progesterone, HO-progesterone, androstenedione, dehydroepiandrosterone) were monitored simultaneously. For assessment of cell viability and the amount of steroids produced/released, a cheap, simple modified Krebs solution was at least comparable to an elaborate cell culture medium. Within the conditions adopted, the cell suspension reacted to varying potassium concentrations as expected. ACTH stimulated steroid production/release only without added substrate. 11 agents known to interfere with steroid biogenesis were tested at 0.1-100 muM. Although all known points of action of the test compounds were located, several showed additional activity. Spironolactone shifted steroid biogenesis from aldosterone and cortisol towards androgenic steroids. Aminoglutethimide inhibited the release of aldosterone with corticosterone as substrate, but not with deoxycorticosterone or progesterone as substrate, revealing an alternative pathway in the biogenesis of aldosterone by-passing corticosterone. Trilostane (0.1-1 muM) completely blocked conversion of pregnenolone to progesterone and OH-progesterone; the release of androstenedione was at most only halved, whereas the release of dehydroepiandrosterone and testosterone was greatly enhanced. This implies isoenzymes of 3beta-hydroxysteroid dehydrogenase/isomerase with different sensitivities towards trilostane. Mitotane, metyrapone, ketoconazole and etomidate all inhibited the mitochondrial P450 (11beta 18 ) enzymes. In addition, mitotane and ketoconazole also inhibited (albeit to a lesser extent) endoplasmic enzymes involved in transformations at C21 and at C17, respectively. Cyproheptadine blocks all transformations with progesterone or HO-progesterone as starting point. Finasteride reduced the release of most steroids, except the androgens, presumably by inhibition of transformations at C3 and at C11. Carbadox and related quinoxalines inhibited not only C18 oxidation but also C21 hydroxylation. Steroidogenesis in these porcine adrenocortical cells in vitro could be described as similar to that in other mammals. A notable feature was that inhibition of the release/production of a steroid hormone was usually accompanied by an increased release of other steroid hormones. This screening model also yields information about the point of action of drugs interfering with steroidogenesis.

Effects of feed additives and veterinary drugs on aldosterone production and release by porcine adrenal cells in vitro.

The preparation of suspensions of porcine adrenocortical cells is described. Within the conditions adopted, the cell suspension responded to various agents as expected. It was possible to screen drugs (standard range 0.3-100 microM, incubation period 1 h) for actions on the production/release of aldosterone by the cortical cells using 1 microM deoxycorticosterone as substrate. Progesterone, pregnenolone or corticosterone were also used as substrates. Feed additives of the quinoxaline type induced a slowly developing inhibition of aldosterone production/release by the cell suspension, which was virtually irreversible. During the standard 1 h incubation period inhibitions of up to 22 +/- 2% of control were observed, which increased upon prolongation of the incubation by 2 h. With 100 microM cyadox the inhibition increased from 19 +/- 2% to 35 +/- 2% with prolonged incubation. Ten nitrofuran compounds exerted a more rapidly developing inhibition (by up to 79 +/- 1% of control) of aldosterone production/release, which was reversible. A submaximal inhibition with 10 microM furazolidone of 21 +/- 5% increased to 40 +/- 1% with longer incubation. The concentrations at which these compounds exerted this effect in vitro were well below the peak blood plasma concentrations encountered after administration of the drugs in therapeutic doses. Polyether-antibacterials/ionophores rapidly inhibited aldosterone production/release (to 26 +/- 1% of control) and this effect was completely reversible. The nitroimidazole compounds tested did not affect aldosterone production/release when deoxycorticosterone or progesterone were used as substrates. With use of corticosterone and to a lesser extent with pregnenolone as substrates a clear inhibition (to 73 +/- 3% of control) of aldosterone production was obtained. Amprolium in concentrations up to 100 microM, with deoxycorticosterone as substrate, did not induce a significant change in aldosterone production/release by the suspension of adrenocortical cells. In the same dose range tylosin and roxarsone induced a small but significant inhibition (by up to 10 +/- 3% of control) of aldosterone production/release, which was not dose-dependent. It is concluded that a wide range of growth-promoting drugs may be able to change aldosterone production/release in the animal.

Column liquid chromatographic determination of carbadox and olaquindox in feeds.

A column liquid chromatographic method for simultaneous determination of carbadox and olaquindox in swine feeds is described. The drugs were extracted from feeds with carbon tetrachloride-dimethylformamide (80:20) at 60 degrees C for 30 min. The extract was mixed with water (25:45). After centrifugation the aqueous layer was chromatographed on a reversed-phase column using gradient elution and ultraviolet detection at wavelengths of 305 and 262 nm. Recoveries from samples fortified at levels of 20-50 ppm were 92 +/- 9% for carbadox and 93 +/- 6% for olaquindox (means +/- standard deviations, n = 71).

Clinical signs and performance of pigs treated with different doses of carbadox, cyadox and olaquindox.

An experiment was designed to study the clinical effects of different levels of carbadox, cyadox and olaquindox in the ration on health, weekly weight gain and feed conversion in pigs. Four different carbadox and olaquindox (25, 50, 100 and 200 ppm) levels and five different cyadox (25, 50, 100, 200 and 400 ppm) levels were tested in groups of 6 pigs during 6 weeks. The 13 groups were compared with a control group fed on the same diet with only vehicle. After one week the first clinical sign, a high faecal dry matter (FDM) content, was observed in the 200 ppm carbadox group, followed by the 100 and 50 ppm carbadox, the 400 and 100 ppm cyadox, and the 200 and 100 ppm olaquindox groups two weeks later. A second clinical sign, urine drinking from the floor or from pen-mates, was observed in the same pens, occurring in the same sequence. The third important clinical sign, a decreased abdominal volume, was also observed in almost the same sequence, however, in the 50 ppm olaquindox and cyadox groups this clinical sign was not observed. Average weekly weight gain was significantly decreased in the higher carbadox and olaquindox groups. Weight gain was significantly increased in the 200 ppm cyadox group. Hematocrit values were significantly increased in the 200 and 100 ppm carbadox groups only. From this study one may conclude that, within the dosages used, carbadox is more harmful than olaquindox for pigs, and it seems that cyadox is harmless for pigs in dosages up to 400 ppm.

Comparative study of the effect of the effect of carbadox, olaquindox and cyadox on aldosterone, sodium and potassium plasma levels in weaned pigs.

To study the effects of olaquindox and cyadox on aldosterone, sodium and potassium in the blood in comparison with the effects of carbadox, weaned pigs were fed these compounds in different doses. Pigs treated with 100 and 200 ppm carbadox showed a significant decline of aldosterone after five and three weeks, respectively, compared with control values. In the 200 ppm group treatment was interrupted at week 4. With olaquindox a continuous, significant decline was found from 50 ppm and above after five weeks, and from 25 ppm and above (but excluding the 100 ppm group), after six weeks. In the cyadox groups a significant decline was measured after six weeks in the 50, 200 and 400 ppm groups. Only the 200 ppm group had an earlier response at three and five weeks. A decrease of sodium to hyponatraemic levels in the carbadox groups was seen after three weeks in the 200, and after five weeks in the 100 ppm group. In the olaquindox groups only the 200 ppm dosage showed a consistent decrease to hyponatraemic levels from four weeks treatment. In the cyadox groups the 200 ppm dosage reached a hyponatraemic level after six weeks. An increase of potassium to hyperkalaemic levels occurred at 100 and 200 ppm carbadox dosage after four and three weeks, respectively, and at 200 ppm olaquindox dosage after four weeks. No hyperkalaemic levels were seen in the cyadox groups. It is concluded that the toxic effect of olaquindox, despite minor differences, is comparable with that of carbadox but that cyadox is less toxic.