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1 beta-adrenoceptor blockade with metoprolol provoked, both at rest and during exercise, a decrease of 'active' renin and angiotensin II together with an increase of 'inactive' renin and unchanged 'total' renin. The significant exercise-provoked increases in angiotensin II, plasma renin activity and 'active', 'inactive' and 'total' renin when on placebo, were reduced by metoprolol. 2 No significant change in serum sodium and potassium and in plasma aldosterone was found during beta-adrenoceptor blockade at rest. During exercise plasma aldosterone dropped significantly without any change in serum sodium or potassium. 3 Plasma noradrenaline increased significantly at rest on metoprolol. The increase in plasma noradrenaline and adrenaline during exercise was similar on placebo and on metoprolol.

Ketanserin (120 mg/day) or placebo was given orally to 14 patients with mild to moderate essential hypertension according to a double blind crossover protocol, each treatment period lasting six weeks. Resting intra-arterial pressure in the recumbent position was reduced from 150/84 to 141/77 mm Hg; the hypotensive effect persisted throughout an uninterrupted graded exercise test to the point of exhaustion. The haemodynamic effects were similar at rest and during exercise. Overall, systemic vascular resistance decreased by 14%, heart rate fell by 5%, but stroke volume and cardiac output increased. Mean pulmonary arterial pressure and capillary wedge pressure were not significantly affected, but pulmonary vascular resistance decreased by 15%. The pressor response to methoxamine was significantly reduced by ketanserin. Both plasma noradrenaline and adrenaline concentrations increased, plasma renin activity and angiotensin II concentration decreased, and plasma aldosterone concentration was unchanged. The data indicate that ketanserin induces arteriolar dilatation, possibly related to an alpha-1-antagonistic action and to a reduced circulating angiotensin II concentration. The haemodynamic response is complex, and an increase in cardiac output limits the hypotensive effect. There is no firm evidence of an effect on venous tone as cardiac filling pressures do not change.

It has been suggested that enkephalins are involved in the gastric relaxation induced by stimulation of the non-adrenergic, non-cholinergic vagal fibres in the cat stomach. Experiments were therefore performed on strips of cat stomach. With longitudinal and circular gastric fundus and corpus strips from reserpinized cats, non-adrenergic, non-cholinergic relaxatory responses could be elicited by transmural electrical stimulation in Tyrode solution containing atropine and 5-hydroxytryptamine. Morphine, leu-enkephalin and met-enkephalin did not influence the tone of the strips or the relaxation evoked by stimulation at 8 Hz, and neither did the opioid antagonist, naloxone. These results do not support the enkephalinergic hypothesis for the non-adrenergic, non-cholinergic vagal fibres in the cat stomach.

1. Although systolic blood pressure elevation is responsible for increased incidence of cardiovascular accidents in old people, the preventive benefit of lowering systolic hypertension in elderly has not been confirmed. 2. A double blind study comparing the effects of a placebo and of an active regimen (hydrochlorothiazide-triamterene with or without methyldopa) in people over 60 years with isolated systolic hypertension has been undertaken by the European Working Party on High blood pressure in the Elderly (EWPHE). 3. The actively treated group shows a lowered sitting blood pressure (-15/6 mm Hg), a mild increase of serum creatine, serum uric acid and blood glucose and a mild decrease of serum potassium after two years of treatment when compared to the spontaneous changes observed in the placebo treated group. 4. The study is continuing to evaluate if the blood pressure reduction prevents or reduces the incidence of cardiovascular accidents, although some biochemical changes were provoked by the treatment.

The presence of dopamine beta-hydroxylase activity in the cerebrospinal fluid of rabbits has been shown using a sensitive radiochemical assay; the identity of the reaction product was confirmed by using thin layer chromatographic techniques. The enzyme found in this fluid has some properties (sedimentation and electrophoretic migration) in common with the best characterized preparation of dopamine beta-hydroxylase, that prepared from bovine adrenal chromaffin granules. It also has these properties in common with the enzyme present in the high-speed supernatants obtained from osmotically disrupted synaptosomes prepared from rabbit brain. When the sciatic nerves of rabbits under urethane anaesthesia were stimulated, or when shaved rabbits were subjected to cold stress, the level of dopamine beta-hydroxylase in the cerebrospinal fluid increased. The increase in response to nerve stimulation was gradual, starting within 90 min of stimulation and remained high for at least 3 h after the stimulation had ended, at which time it was 280% of the normal value. There was no equivalent increase in the protein concentration of the cerebrospinal fluid nor was there a change in the enzyme activity when sciatic nerves were exposed but not stimulated. The enzyme present in the cerebrospinal fluid during this period of high activity is identical in its sedimentation and electrophoretic properties to that present in normal fluid. It is suggested that the dopamine beta-hydroxylase activity in cerebrospinal fluid may be derived from noradrenergic neurons within the brain and that the enzyme is released together with noradrenaline.

The influence of body posture and muscular exercise on plasma noradrenaline and adrenaline concentrations was studied in man. The radiometric method of Passon and Peuler (Passon, Ph. and Peuler, J. (1973) Anal. Biochem. 51, 618) was used with slight modifications. With rigorous standardisation of sampling and storage procedures, reproducible results were obtained. Basal values of plasma catecholamines in man can be obtained from subjects after 30 min of rest in the supine position.

The latter was due to a reduction in cardiac mortality (−38%, p=0.036) and a nonsignificant decrease in cerebrovascular mortality (−32%, p=0.16). In the double-blind part of the trial, the total mortality rate was not significantly reduced (−26%, p=0.077). However, cardiovascular mortality was reduced in the actively treated group (−38%, p=0.023), owing to a reduction in cardiac deaths (−47%, p=0.048) and a non-significant decrease in cerebrovascular mortality (−43%, p=0.15). Deaths from myocardial infarction were reduced (−60%, p=0.043), and study-terminating morbid cardiovascular events were significantly reduced by active treatment (−60%, p=0.0064). Non-terminating cerebrovascular events were reduced (−52%, p=0.026), but the non-terminating cardiac events were not (+ 3%, p=0.98). In the patients randomised to active treatment there were 29 fewer cardiovascular events and 14 fewer cardiovascular deaths per 1000 patient years during the double-blind part of the trial.

SummaryThe author provides a description and discussion of a fluorimetric method for differential estimation of adrenaline and noradrenaline in urine.The importance of this method in differential diagnosis of arterial hypertension is stressed.

Nitroglycerol, papaverine, and acetylcholine were tested against noradrenaline and potassium contractions of the isolated artery of the rabbit ear. The order of potency of the vasodilators varies with

Prenylamine, given orally to 4 healthy male volunteers in a dose of 180 mg/day, for 2 weeks: 1. (a) significantly enhanced the increase in respiratory minute volume in response to exercise; 2. (b) did not significantly influence the resting excretion of dopamine, noradrenaline, adrenaline, homovanillic and vanillylmandelic acid; 3. (c) significantly decreased the usual increase in the excretion of noradrenaline which occured during exercise.

119 elderly, hypertensive patients were followed-up for 1 year and 48 for 2 years in a double-blind, randomised, controlled trial in which they received either placebo or 25-50 mg hydrochlorothiazide and 50-100 mg of triamterene daily. Half of the active treatment group also received 250 mg to 2 g methyldopa daily. After 2 years the active treatment group had an average increase in fasting blood-sugar of 9·6 mg/dl compared with an average fall of 3·1 mg in the placebo group (P

Treatment of a malignant pheochromocytoma patient with a-methyl-p-tyrosine was effective in controlling the raised arterial blood pressure and the associated clinical signs and was followed by a decrease of urinary noradrenaline and vanillylmandelic acid and by a increase in urinary dopamine and homovanillic acid. In the course of this treatment large amounts of α-methyl-dopamine and detectable amounts of α-methyl-noradrenaline were found in the urine.

The uterine inhibitory effect and potential maternal and fetal side effects of two beta-mimetic compounds, ritodrine hydrochloride and fenoterol hydrobromide, were compared in a randomized trial. The drugs were administered by intravenous infusion to 24 healthy term nulliparous women during effective first-stage labour; each of them received fenoterol (1, 2, or 4 microgram/min) or ritodrine (100, 200, or 400 microgram/min). There was no difference between the drugs in the intensity of the uterine inhibition. However, for a similar inhibitory effect, the duration of tocolysis was longer after ritodrine. During the intrapartum and neonatal periods, neither compound induced any change in the fetal parameters investigated, and their effects on maternal parameters were comparable.

1. A total of 450 hypertensive patients above the age of 60 years have entered the double-blind multicentre trial of the European Working Party on High blood pressure in Elderly (EWPHE). After stratification and randomization half were treated with one capsule daily containing 25 mg of hydrochlorothiazide and 50 mg of triamterene and half were given placebo. In those receiving active treatment, if blood pressure control was not adequate they were given a second capsule and if necessary up to 2 g of methyldopa/day. 2. No significant differences between the groups were present before randomization. A significant blood pressure difference of 25/10 mmHg was obtained between the groups and maintained during 4 years of follow-up. No major disturbances in serum potassium or serum sodium were noted with the present drug combination. 3. During the initial phase an increase in serum creatinine and serum uric acid was noted in the actively treated group, which was maintained during the later years. This increase in serum creatinine in the actively treated group was related (P = 0·003 and r = −0·247) to the decrease in sitting systolic blood pressure. Changes in serum uric acid were (r = 0·3 and P = 0·003) correlated with the changes in serum creatinine both in the placebo and in the actively treated group, but independent of the change in creatinine; the serum uric acid was on average 1 mg higher in the actively treated than in the placebo group. 4. Fasting blood glucose did not change significantly in the placebo-treated group but in the active treatment group the rise was statistically significant. 5. A favourable influence on prognosis by active treatment can be expected on the basis of the blood pressure reduction and in the absence of major electrolytes disturbances. However, the balance between this decreased risk and the increased risk produced by the rise in blood glucose and the other treatment effects remains to be determined. Therefore the trial continues and more patients are being admitted.

A semi-automated fluorimetric method for the quantitation of urinary catecholamines (dopamine, noradrenaline and adrenaline) combined with manual methods for the quantitation of their metabolites (homovanillic acid, normetanephrine, metanephrine and vanillylmandelic acid) is described. It provides a sensitive and reproducible analytical technique for routine use. Values obtained in healthy adults are given.

The contribution of beta 1-adrenoceptors to the regulation of plasma renin activity was investigated in nine healthy sodium-replete volunteers: seven subjects received a cumulative intravenous dose of 75 micrograms/kg prenalterol, a predominant beta 1-adrenoceptor agonist, and two subjects only vehiculum. In the seven actively treated subjects beta 1-adrenoceptor agonism increased (P less than 0.001) systolic intra-arterial pressure by an average of 16 +/- 4 mm Hg and heart rate by 19 +/- 3 beats min. These increases were significantly (P less than 0.04) different from the changes observed in the two control subjects (+ 3 +/- 4 mm Hg and -1 +/- 4 beats/min, respectively). Plasma renin activity, however, tended to decrease in both the actively (-38%) and saline (-28%) treated subjects. Predominant beta 1-adrenoceptor agonism, powerful enough to increase systolic pressure and heart rate does not increase plasma renin activity in supine sodium-replete normal man.

Mean intra-arterial pressure (P-), heart rate (HR), cardiac index (CI), total peripheral resistance index (TPRI), and plasma renin activity (PRA), norepinephrine (PNE), and epinephrine (PE) were estimated in five normal male subjects placed on a low-sodium diet for the previous 7 days. Subjects were studied during rest in recumbency and during intravenous infusion of either glucose or saralasin in a) recumbent position, b) sitting position on the bicycle ergometer, and c) during submaximal graded exercise. At rest recumbent saralasin induced pressure changes that were closely related to logPRA. During exercise the increase in P- was significantly lower during saralasin as compared to glucose from 110 W on, related to a greater reduction in TPRI. The increase of PRA during exercise was about three times greater with saralasin as compared to glucose, but the rises in PNE and PE were similar in both series of tests. Angiotensin II may thus have a role in the maintenance of P- in the supine sodium-deplete normal subjects, and stimulation of the renin angiotensin system during physical exercise contributes to a minor extent to the increase in P- in these conditions.

In developing countries, prevention and treatment of parasitic diseases present not only a challenge to the health services but also a test case to the efficiency of health education in general. In these countries, medical schools have started and continue to function on a Western pattern of medical education. This may have well served the provision of hospital-based services on a well-tested scientific and professional tradition. The system is, however, inappropriate when it comes to the provision of preventive care and mass treatment, and to the introduction of adaptational and developmental changes which are constantly needed in developing countries as well on the health service as on the educational side. As a consequence the whole enterprise is in danger of becoming increasingly irrelevant and insufficient. The fact that both health services and medical curricula are at present seriously questioned in developed countries as well, lends an even greater importance to their re-assessment and adaptation in developing countries.

Systemic administration of each of the drugs studied (phenoxybenzamine, yohimbine, phentolamine, nicotine, physostigmine and pentylenetetrazol) caused an increase in the dopamine β-hydroxylase activity per unit volume of cerebrospinal fluid. The increase was gradual starting within 90 min after injection of the drug and remained high for at least 3 h. At that time the dopamine β-hydroxylase levels after treatment with phenoxybenzamine and yohimbine reached values of 600% and 580%, respectively, of the control. The increase in dopamine β-hydroxylase activity upon phenoxybenzamine treatment was dose dependent. Injection of pentylenetetrazol caused an increase in dopamine β-hydroxylase to 230% of the control value. Pretreatment of rabbits with an intracisternal injection of 6-hydroxydopamine not only caused a 68% decrease in the noradrenaline content and a 69% decrease in the dopamine β-hydroxylase levels in the brain, but also led to a 52% fall in the dopamine β-hydroxylase level of the cerebrospinal fluid. Upon injection of pentylenetetrazol into rabbits pretreated with 6-hydroxydopamine, the dopamine β-hydroxylase levels in the cerebrospinal fluid only reached a mean value of 0.98 units/ml compared with 2.62 units/ ml for control rabbits injected with pentylenetetrazol; the increase in the blood level of dopamine β-hydroxylase activity was, however, unaffected. Data derived from normal and 6-hydroxydopamine pretreated rabbits revealed a fairly good correlation between dopamine β-hydroxylase levels in the cerebrospinal fluid and the brain. From these experiments it is concluded that dopamine β-hydroxylase activity in the cerebrospinal fluid is derived from central noradrenergic neurons and that drugs which increase central noradrenergic activity also increase dopamine β-hydroxylase levels in the cerebrospinal fluid. It is further suggested that determination of dopamine β-hydroxylase activity in the cerebrospinal fluid may be a sensitive and relatively easy method to assess central noradrenergic activity.

We studied the effects of labetalol, an alpha- and beta-adrenoceptor antagonist, on maximum exercise heart rate and on plasma renin, aldosterone, noradrenaline, and adrenaline levels at rest and during exercise in hypertensive patients. The dose of labetalol was doubled weekly from 0.3 to 2.4 g per day. The maximum exercise heart rate fell significantly during labetalol treatment, and there was a significant correlation between exercise tachycardia and the dosage of labetalol. Plasma renin activity and aldosterone concentration at rest decreased during treatment with labetalol. The exercise-induced increase in plasma renin activity was reduced by labetalol. Labetalol did not cause any significant changes in plasma noradrenaline and adrenaline at rest or during exercise.

Dopamine-beta-hydroxylase (D beta H), a glycoprotein enzyme which converts dopamine into noradrenaline, was purified from C1300 mouse neuroblastoma and used to raise antibodies in rabbits. Using an indirect immunofluorescence technique the cellular localization of D beta H in C1300 mouse neuroblastoma was compared with that of the superior cervical ganglion. C1300 neuroblastoma D beta H was found to be predominantly localized in the plasma membrane, in contrast to its intracellular localization in the superior cervical ganglion of A/J mice. At least part of the enzyme was found to be associated with the external side of the plasma membrane.

A density and velocity gradient centrifugation study of C1300 mouse neuroblastoma showed that ATP is nearly absent from noradrenaline-containing granules and is mainly localized in mitochondria, suggesting that in this tissue ATP is not involved in the storage of noradrenaline.

SUMMARY 1.The angiotensin II antagonist, 1-Sar-8-Ala-angiotensin II (saralasin), was infused intravenously at a rate of 10 μg/kg per min in thirty-three hypertensive patients, on a normal sodium diet (130 mmol per day) and/or during sodium depletion by low sodium diet (20 mmol per day) and chlorthalidone. 2. In both series, saralasin induced a transient rise in intra-arterial pressure (P < 0.01), accompanied by a slight decrease in heart rate (P < 0.01). The elevation of systolic arterial pressure reached its maximum after 4 min and was more pronounced in sodium-replete patients. Plasma noradrenaline was significantly elevated by 29.7% (P

Results of the European Working Party on High Blood Pressure in the Elderly (EWPHE) trial have been analysed in relation to age, sex, blood pressure, and previous cardiovascular disease. Cardiovascular mortality and the cardiovascular study-terminating events were significantly and independently related to treatment, age, cardiovascular complications at randomisation, and systolic but not diastolic blood pressure. The benefits of treatment observed in the trial seemed to be independent of entry blood pressure and the presence or absence of cardiovascular complications at entry. There was some evidence that treatment effect decreases with advancing age. Little or no benefit from treatment could be demonstrated in patients over the age of 80 years, the great majority of whom were women.

The metabolism of nitroglycerin (trinitrin) was studied in dogs and rabbits. After intravenous injection of nitroglycerin in either species, plasma levels immediately declined and then gradually increased; maximum plasma levels occurred between 10 and 20 min after injection. This peculiar course of the plasma levels was due to redistribution of the drug in different organs. The blood pressure responses to nitroglycerin did not parallel the plasma levels. Pretreatment of rabbits with SKF 525 A, an enzyme inhibitor, or with phenobarbital, an enzyme inducer, markedly influenced the plasma levels but did not affect the vascular effects of nitroglycerin. After oral administration of nitroglycerin, blood pressure was normal despite high plasma levels. The vascular effects of nitroglycerin did not seem to be determined by its metabolism or plasma levels.

Two proteins present in noradrenergic vesicles of the splenic nerve (dopamine beta-hydroxylase and chromogranin A) are released into the perfusate from the spleen when the splenic nerve is stimulated. Experiments in which drugs were added to the perfusion fluid showed that the proteins were released from terminals of the splenic nerve. There was a correlation between the amounts of the proteins released and the quantity of noradrenaline released; and the release process was dependent upon calcium. It is suggested that the proteins are released from the large dense-cored vesicles present in the terminals of the splenic nerve, and that secretion from these vesicles occurs by exocytosis.

Une stimulation electrique in situ de la rate du chien provoque l'apparition de membranes contenant de la dopamine-β-hydroxylase. Les membranes sont tres probablement le resultat d'une fusion de la membrane axonale et de la membrane vesiculaire, pendant le processus de decharge. Une telle formation de membranes indique que les particules chargees de noradrenaline ne peuvent etre utilisees qu'une seule fois.

Experiments performed in anesthetized dogs have shown that occlusion of the coeliac and mesenteric arteries may determine minor increases of systemic blood pressure, obviously of hemodynamic nature and not induced by baroreceptive vasomotor reflexes. Increase of pressure into the mesenteric arterial circulation does not decrease the systemic blood pressure. The aortic and carotid sinus baroreceptors are the major means of the reflex blood pressure homeostasis. Evidence for the existence of specific chemoreceptors in the abdominal vascular area could not be obtained.

Metanephrine-7- 3 H, given to rabbits by intravenous infusion, was found to be O- and N-demethylated in vivo , as shown by the occurrence of adrenaline, noradrenaline and 3:4-dihydroxymandelic acid in urine and liver.

Subcellular fractionation of dog spleen by differential centrifugation has shown both endogenous and infused labelled noradrenaline to occur to a large extent in particle-bound form, the subcellular distribution of which is very similar to the pattern of distribution of acid phosphatase. Thermal activation experiments suggest that this particle-bound amine occurs partly in labile form and partly in a more stable form. There are indications pointing to the presence of lysosomes in dog spleen.

Nitroglycerin (trinitrin) was studied in the intact anesthetised dog, in the perfused femoral artery or lateral saphenous vein of the dog and on isolated vessels (strips) of rabbit and dog. The behaviour of a vascular bed after systematic administration of nitroglycerin was dependent on reflex adjustments of sympathetic tone. The vasodilator effects of nitroglycerin on perfused vessels or vascular strips were dependent on the time of its administration; administration during an existing contraction was much more effective than administration before contraction. That is, a contraction was more easily abolished than prevented. This behaviour of nitroglycerin contrasts with that of acetylcholine or papaverine.

Experiments on the isolated perfused dog spleen in which the effect of intra-arterially injected catecholamines and splenic nerve stimulation were studied on vascular resistance, venous outflow and organ weight showed that (a) noradrenaline injection and splenic nerve stimulation provoked an increase in vascular resistance, whereas adrenaline injection was followed successively by a quick increase in perfusion pressure and a pronounced decrease of perfusion pressure, apparently due to a stimulation of vascular β-receptors, and then by a secondary increase in perfusion pressure, (b) the reduction of splenic weight was much less pronounced after noradrenaline injection than after adrenaline injection and splenic nerve stimulation, presumably due to a higher uptake of exogenous noradrenaline by the adrenergic nerve endings in the arterial wall, (c) direct evidence for the presence of vascular β-receptors was obtained by the injection of isoproterenol in isolated spleens maintained at a nearly physiological tone and by splenic nerve stimulation after ɑ-receptor blockade, and (d) the neurotransmitter released on splenic nerve stimulation was identified by paper chromatography as being predominantly noradrenaline together with small amounts of dopamine.

The subcellular particles in axons of the splenic nerve have been studied by centifrugation techniques. By differential centifrugation, five different types of particle could be distinguished and partly separated: noradrenaline-containing particles (noradrenergic vesicles), large and small lysosomes, mitochondria, and microsomal particles. In density gradient centrifugation, only one type of noradrenergic vesicle could he demonstrated. The noradrenergic vesicles and the mitochondria contain ATP. Two proteins (chromogranin A and dopamine β-hydroxylase) are present in the noradrenergic vesicles.

Eine Methode zur Perfusion der isolierten Milz des Hundes wird beschrieben, bei welcher die Variationen im Noradrenalin-output nach Sympathikusstimulation mit Veranderungen im In-flow, Out-flow und differentiellen Flow sowie im Milzvolumen korreliert erfasst werden konnen. Der Einfluss von Kokain und Phenoxybenzamin auf diese Parameter wird gepruft.

After 30 min rest in the lying position, 12 healthy male volunteers (average age 22 years) received, in a randomized double-blind cross-over protocol, either saline or naloxone (10 mg iv followed by a continuous infusion of 10 mg/hr). Thereafter they rested for a further 30 min in the recumbent position and for 15 min sitting on a bicycle ergometer; they then exercised to exhaustion. At rest plasma levels of adrenocorticotropin (ACTH), cortisol, and aldosterone increased during infusion of naloxone, while body temperature decreased. During exercise the difference in plasma ACTH between naloxone and saline periods was abolished, while the differences in plasma cortisol and aldosterone lost statistical significance. Intra-arterial pressure, heart rate, ventilation, O2 uptake, and CO2 output were continuously monitored throughout the experiment and were not affected by naloxone. This was also the case for several hormonal and biochemical measurements, including those of plasma renin, angiotensin II, norepinephrine, 13,14-dihydro-15-keto-prostaglandin F2 alpha, glucose and lactate, and serum insulin and growth hormone. Exercise performance was not changed by naloxone. In conclusion (1) during exhaustive graded exercise of short duration opioidergic inhibition of the pituitary-adrenocortical axis is probably not sustained, (2) apart from the latter mechanism, the present study does not support the hypothesis that endogenous opioids are involved in various hemodynamic, respiratory, and hormonal responses to this type of exercise.

Dans 18 cas de neuroblastome humain la noradrenaline (NA) et la dopamine-β-hydroxylase presentent des profils de distribution intracellulaire identiques, suggerant un stockage dans la meme particule. Le contenu en NA de ces particules n'est pas inferieur a celui des particules du nerf splenique; on peut en conclure qu'un stockage defectueux de NA dans les cas de neuroblastome est peu probable.

THE existence of different noradrenaline pools in sympathetically innervated tissues has been proposed on the basis of both pharmacological and biochemical studies1,2. Recent morphological evidence3,4, showing that the terminals of splenic nerves contain two distinct size populations of granulated vesicles and that only one of them is present in the preterminal processes, has given additional support to this theory. We now present biochemical evidence for the existence of two types of noradrenaline storage particles in the dog spleen and compare some of their properties with those of the noradrenaline vesicles of bovine splenic nerve.

Eine einfache, schnelle und empfindliche Methode zur dunnschichtchromatographischen Trennung von 0,2–1µg Menge von Noradrenalin, Adrenalin, Normetanephrin, Metanephrin, 3,4-Dihydroxy-mandelsaure und 3-Methoxy-4-hydroxymandelsaure wird beschrieben.