The depolarization-induced outflow of D-[3H]aspartate from rat brain slices is modulated by metabotropic glutamate receptors

Rat brain slices were used to study the effects of different metabotropic glutamate receptor ligands on (i) the depolarization (30 mM KCl)-induced outflow of previously taken up D-[3H]aspartate; (ii) the inhibition of forskolin (30 microM)-induced cyclic AMP accumulation; and (iii) the hydrolysis of phosphoinositides. In addition, the localization of mRNAs coding for different metabotropic glutamate receptor subtypes was detected using in situ hybridization. (1S-3R)-1-Aminocyclopentane-1,3-dicarboxylic acid (30-300 microM), a non selective metabotropic glutamate receptor agonist, significantly increased the KCl-induced output of radioactivity from cortical slices, whereas it inhibited the output from striatal slices. Conversely, (1S,3S,4S)-carboxycyclopropylglycine (0.1-1 microM), a relatively selective agonist of the mGluR2 metabotropic glutamate receptor subtype, had an inhibitory effect on the output of D-[3H]aspartate from both cortical and striatal slices and proved to be the most potent metabotropic glutamate receptor agonist in inhibiting cyclic AMP accumulation, but not in stimulating phosphoinositide hydrolysis. Since 2-amino-4-phosphonobutyrate (a mGluR4, mGluR6 and mGluR7 agonist) was not active in any of the assays tested, we hypothesized that the mGluR2 subtype could be involved in these events. Accordingly, mGluR2 mRNA expression was abundant in cortical neurons projecting to the striatum. Our experiments suggest that the stimulation of metabotropic glutamate receptors may either decrease or increase transmitter release depending on the subtype that prevails in the region under study.

Chromosomes 1, 11, and 13 are frequently involved in karyotypic abnormalities in metastatic Merkel cell carcinoma

We report a cytogenetic study of six Merkel cell carcinomas (MCC) in which rearrangement of chromosome 1 was noted in four cases: two cases were trisomic, in one case there was a reciprocal translocation between chromosomes 1 and 5 [t(1;5)(p36;p13)], and in the fourth case all cells had a normal chromosome 1 and three derivatives, a del(1)(p22) and del(1)(q21), and a translocation involving material of unknown origin to the long arm, t(1;?)(q21;?). Four cases demonstrated loss of chromosome 13; in two of these, both copies were lost, and the survival for these two patients was much longer than is common for MCC patients. Partial trisomy of chromosome 11 was noted in two cases, and two patients demonstrated loss of chromosome 22 in all cells examined. Although no consistent chromosome change was noted in our cases, our data and those of previously published reports, show that abnormalities of chromosomes 1, 11, and 13 occur in 30-47% of cytogenetic reports of this rare malignancy.

Introduction of a putative dopaminergic prodrug moiety into a 6,7-substitution pattern characteristic of certain 2-aminotetralin dopaminergic agonists

On the basis of the premise that the dopaminergic agonist profile of 2-(di-n-propylamino)-5-hydroxy-6-methyltetralin (1a) is due to in vivo oxidation of the 6-methyl moiety and that 1a may represent a novel prodrug strategy, the vicinal methyl-hydroxyl substitution pattern was incorporated into the 6- and 7-positions of 2-(di-n-propylamino)tetralin to give the 6-methyl-7-hydroxy and 6-hydroxy-7-methyl isomers 8 and 9, respectively. A multistep synthetic approach was devised which permitted preparation of target molecules 8 and 9. Pharmacological data revealed that both target compounds exhibit modest dopamine-like effects in the cardioaccelerator nerve assay in the cat, but neither appeared to be metabolically activated as was the case with 1a. The effects of 9 (but not of 8) were antagonized by pretreatment with haloperidol. Thus, the 5-hydroxy-6-methyl substitution pattern in the 2-aminotetralins remains unique as a dopaminergic agonist prodrug structure.

5-HT1A-receptor antagonism: N-alkyl derivatives of (R)-(-)-8,11-dimethoxynoraporphine

Prompted by previous findings that a p-dimethoxy substitution pattern on an aromatic ring permits retention of dopaminergic agonist effects in certain ring systems, catechol derivatives of which are potent dopaminergic agonists, an 8,11-dimethoxy substitution pattern was introduced into the aporphine ring in place of the 10,11-dihydroxy moiety in apomorphine. Acid-catalyzed rearrangement of an appropriate morphine derivative provided the aporphine ring system with retention of the stereochemical integrity of the 6a asymmetric center. The hydroxyl group at position 10 was removed by catalytic hydrogenolysis of its phenyltetrazoyl ether. The methyl ether of the resulting 11-hydroxyaporphine was iodinated in high yield at position 8 with trifluoroacetyl hypiodite. This is the first account of synthesis of an iodinated aporphine derivative. The 8-iodo substituent was replaced with methoxyl by reaction with sodium methoxide and cuprous iodide. Neither the N-methyl target compound 7 nor the N-n-propyl derivative 8 demonstrated dopaminergic nor serotonergic agonism. However, 7 exhibited receptor-binding characteristics and other pharmacological properties suggesting that it may be a 5-HT1A receptor antagonist.

Are visual-perceptual and visual-motor skills separate abilities?

This study explored the independence of visual-perceptual and visual-motor abilities. Scores on the Motor-free Visual Perception Test were correlated by Pearson's method with scores on tests that weight the visual-perceptual, motor, and visual-motor components differently. Small but significant correlations were found between the Motor-free Visual Perception Test and tests of visual-motor integration, but there was no relationship between the motor-free test and tests of motor ability. These findings support the premise that tests of visual perception, visual-motor integration, and motor ability measure different skills.

Total and renal sympathetic nervous system activity in alcoholic cirrhosis

Basal sympathetic nervous system activity was assessed in 8 unmedicated patients with alcoholic cirrhosis using a previously developed radiotracer method for measuring total and renal noradrenaline release to, and clearance from, plasma. Compared to the control group total noradrenaline clearance was significantly increased in the patients with advanced alcoholic cirrhosis (Pugh grade C) [1.89 +/- 0.13 vs 1.51 +/- 0.11 l/min, P less than 0.05) indicating that endogenous plasma noradrenaline levels underestimate total sympathetic nervous system activity in these patients. Renal noradrenaline clearance was similar to controls independent of the severity of the liver disease. Both total and renal noradrenaline release were significantly increased in the patients with cirrhosis. The ratio of renal to total noradrenaline release was similar in cirrhotic (26 +/- 7%) and control (23 +/- 5%) groups. Increased arterial plasma adrenaline levels, indicative of adrenal medullary stimulation, were also evident in the patients with cirrhosis and correlated significantly with total noradrenaline spillover (r = 0.732, P less than 0.05). These results strongly suggest that in patients with cirrhosis, rather than a preferential increase in renal sympathetic tone, the increase is part of a pattern of generalized sympathoadrenomedullary activation. Although renal renin secretion was significantly increased in the cirrhotic group no correlation with renal noradrenaline release was seen (r = 0.199), raising the possibility that in cirrhosis renal sympathetic tone is not a major determinant of renal renin secretion. Finally, renal noradrenaline release did not correlate with renal blood or plasma flow but an influence of the sympathetic nervous system on renal function was suggested by the correlation observed between total noradrenaline spillover and impaired salt (r = -0.683, P less than 0.05) and water excretion (r = -0.702, P less than 0.05) demonstrated in the cirrhotic patients.

Two patients with abnormalities of regional sympathetic nervous tone

The traditional biochemical tests of sympathetic nervous system function used in clinical diagnosis (urine and plasma catecholamine measurements) are indices of "overall" sympathetic nervous activity, and incapable of detecting localised changes in sympathetic tone confined to individual organs. Recently developed radiotracer methods, which enable the pattern of sympathetic nervous dysfunction in disease states to be delineated, were used to detect abnormalities in regional sympathetic nervous system activity in two patients presenting problems in management. In one, the abnormality of sympathetic function was iatrogenic, a post-sympathectomy denervation of the lower regions of the body, associated with incapacitating postural hypotension. In the other, unexplained persistent sinus tachycardia proved to be due to an increase in sympathetic nervous tone restricted to the innervation of the heart. Knowledge of the underlying sympathetic nervous pathophysiology in these patients influenced the choice of drugs subsequently used in their treatment.

Estimation of 'total' renal, cardiac and splanchnic sympathetic nervous tone in essential hypertension from measurements of noradrenaline release

The overall rate of release of noradrenaline to plasma was increased in 31 patients with essential hypertension; the median value was 32% (526 pmol/min) higher than in 22 subjects with normal blood pressure. To ascertain the pattern of sympathetic nervous system activation underlying this abnormality, regional sympathetic nervous activity was estimated, from radiotracer-derived estimates of organ-specific noradrenaline release to plasma, in the kidneys, heart and hepatomesenteric circulation. Renal sympathetic nervous tone was preferentially increased in essential hypertension, especially in young patients with hypersecretion of renin. Cardiac noradrenaline release (and possibly cardiac sympathetic tone) was also higher in hypertensive patients; the difficulty in interpretation here arises because left ventricular mass is also increased in essential hypertension. Approximately half of the surfeit in total noradrenaline release to plasma noted in hypertensive patients was accounted for by the increased cardio-renal noradrenaline release. The balance comes from undetermined sites, but not from the splanchnic circulation, in which sympathetic nervous activity was not increased.

Effects of changes in physical activity on blood pressure and sympathetic tone

We investigated the relationship between the level of physical activity and blood pressure (BP). Twelve sedentary normotensive subjects were studied after consecutive one-month periods at four different levels of daily activity. These were minimal activity; usual sedentary activities; exercise three times weekly for 45 min at 60-70% maximum capacity (Wmax) on a bicycle ergometer and similar exercise performed daily. The order of the various levels of physical activity were randomised according to a Latin square. As expected there was a progressive increase in Wmax, maximum oxygen consumption and fall in resting and exercise heart rate with increasing activity. Supine blood pressure averaged 133/69 mmHg at the end of the sedentary period and fell by 10/8 mmHg after one month of exercise three times weekly and 12/8 mmHg after daily exercise (both P less than 0.001). The fall in resting BP with increased activity was due to lowering of total peripheral resistance. These haemodynamic changes were associated with biochemical evidence of marked reduction in overall sympathetic tone in 10/12 subjects especially after the period of daily exercise. Increased physical activity for one month lowers blood pressure in normotensive subjects. The fall with daily exercise is similar to that after some centrally-acting antihypertensive drugs, and may be due to a reduction in sympathetic nervous activity.

Plasma noradrenaline kinetics in humans

Recently developed radiotracer methods for measuring the overall rate of release of noradrenaline to plasma, for the body as a whole, can be used to estimate 'total sympathetic nervous system activity' in humans. These techniques find application in clinical studies of sympathetic nervous physiology and pharmacology. The inherent weakness of any biochemical test of global sympathetic tone such as this lies in the fact that sympathetic nervous system responses typically show regional differentiation. Biochemical indices of overall sympathetic activity are insufficiently discriminating to delineate patterns of sympathetic nervous response, representing instead an algebraic sum of all regional increases or decreases in sympathetic tone. Modification of the whole-body radiotracer methodology enables organ-specific sympathetic nervous system activity to be estimated, from measurements of regional release of noradrenaline to plasma. This should facilitate investigation of possible sympathetic pathophysiology in disease states. Illustrative of potential application of the method are preliminary findings of increased renal sympathetic nervous tone in young patients with essential hypertension, and of selective activation of sympathetic nerves to the kidney by diuretics.

Measurement of total and organ-specific norepinephrine kinetics in humans

A variety of biochemical tests, most notably measurement of the plasma concentration of norepinephrine, have been used to quantify overall sympathetic nervous system activity in humans. Plasma norepinephrine values provide a fallible index of sympathetic activity in that they are dependent in part on the rate of removal of norepinephrine from plasma. Measurement of the rate of release of norepinephrine to plasma is a better guide to overall sympathetic nervous tone because it avoids this confounding influence of norepinephrine plasma clearance. The overall norepinephrine spillover measurement, however, suffers from one major limitation: the sources of the released norepinephrine are not identified. Recently developed radiotracer techniques allow the estimation of regional sympathetic nervous activity from measurements of the organ-specific norepinephrine spillover rate. We find that the lungs are the main source of norepinephrine release to plasma, with mean pulmonary norepinephrine spillover of 159 ng/min constituting 40% of total norepinephrine release. Pulmonary norepinephrine release exceeded the combined norepinephrine spillover from the heart (3%), kidneys (17%), and hepatomesenteric circulation (8%).

Traumatic ligamentous instability of the cervical spine in children

Sixteen cases of dislocation and ligamentous disruptions of the cervical spine in children are reported. In five cases resulting from injury to the upper cervical spine, the roentgenographical features of the instability at the C1-C2 level are documented and their therapeutic orientation is defined. Eleven injuries were of the lower cervical spine: three dislocations, two of which were old cases, and eight serious ligamentous disruptions. Diagnosis of serious ligamentous disruptions was based on precise radiographic criteria: increase of the interspinous distance, loss of parallelism between the articular processes, and posterior widening of the disc space. The indications for surgical fixations in serious ligamentous disruptions depend on persistence of the clinical and radiological signs after a long orthopedic immobilization.

Influence of variation in dietary sodium intake on biochemical indices of sympathetic activity in normal man

The effects of variation in dietary sodium intake on biochemical indices of sympathetic activity were investigated in normal subjects. Sodium restriction for 7 days (mean urinary sodium excretion 21 mmol/day, s.e.m. = 4) increased supine plasma noradrenaline concentration significantly (1.78 nmol/l, s.e.m. = 0.23) compared to levels during medium sodium intake (1.31 nmol/l, s.e.m. = 0.14) and high sodium intake (1.35 nmol/l, s.e.m. = 0.25), when urinary sodium excretion averaged 186 (s.e.m. = 24) and 310 (s.e.m. = 43) mmol/l respectively. Plasma adrenaline concentrations did not vary significantly. During sodium restriction, the apparent release rate of noradrenaline increased significantly; noradrenaline clearance remained unchanged. No changes were observed in the heart rate response after beta-adrenoceptor stimulation with isoprenaline, suggesting that increased sympathetic activity during sodium restriction did not necessarily alter cardiac beta-receptor sensitivity. The responses to cardiac autonomic blockade with propranolol and atropine did not vary with sodium intake. These observations suggest that the sympathetic response to sodium restriction may not be generalized, excluding, in particular, the sympathetic nerves to the heart.

Contribution of individual organs to total noradrenaline release in humans

Plasma noradrenaline measurements are a fallible guide to sympathetic nervous tone, being dependent on noradrenaline plasma clearance. We have developed radiotracer techniques, based on measurement of the rate of spillover of noradrenaline to plasma, to simultaneously estimate total, and organ-specific, sympathetic nervous activity in humans. In 27 unmedicated subjects without renal or liver disease, or cardiac failure, regional noradrenaline spillover rates were as follows: lungs 138 +/- 36 ng/min (mean +/- SE) (33% of total noradrenaline spillover), kidneys 77 +/- 10 ng/min (22% of total), skeletal muscle 64 +/- 11 ng/min (20%), hepatomesenteric 29 +/- 9 ng/min (9%), skin 18 +/- 4 ng/min (5%), and heart 11 +/- 4 ng/min (3%). Organ-specific noradrenaline spillover measurements are well suited to the elucidation of sympathetic nervous system pathophysiology in human diseases. Since the sympathetic nervous system outflow to individual organs is not activated or suppressed uniformly in different disease states, biochemical measures of "overall sympathetic nervous activity" are insufficiently specific for this purpose.

Total, and organ-specific, noradrenaline plasma kinetics in essential hypertension

We have developed radiotracer techniques, based on measurement of the rate of spillover of noradrenaline to plasma, to simultaneously estimate total, and organ-specific, sympathetic nervous activity in humans. In 27 unmedicated subjects without renal or liver disease, or cardiac failure, regional noradrenaline spillover rates were as follows: lungs 33% of total noradrenaline release to plasma, kidneys 22%, skeletal muscle 20%, hepatomesenteric 9%, skin 5%, and heart 3%. These findings have relevance to numerous previous studies on the importance of the sympathetic nervous system in the pathogenesis of human essential hypertension. The indices of overall sympathetic nervous tone which have been used, such as measurements of plasma noradrenaline concentration or total NA release to plasma, are seen to be not sufficiently specific, since the organs and regions thought to be central to hypertension pathogenesis (kidney, heart, splanchnic circulation) are responsible for no more than 35% of all noradrenaline released to plasma. Organ-specific noradrenaline spillover measurements are better suited to the elucidation of any sympathetic nervous system pathophysiology in human hypertension. Early results point to an increase in renal sympathetic tone in young patients with essential hypertension.

Noradrenaline turnover during under- and over-eating in normal weight subjects

Adjustments to sympathetic nervous system activity may regulate constant body weight despite wide variations in energy intake. To test this six normal weight subjects were studied at three different energy intakes (low, weight maintaining and high). Noradrenaline turnover was measured on the tenth day of each diet. Both noradrenaline appearance rate and noradrenaline clearance increased significantly with increasing energy intake and were a more sensitive indices than the plasma noradrenaline concentrations which rose, but not significantly. Fasting triiodothyronine (T3) rose and reverse T3 fell with increasing energy intake, while thyroxine (T4) concentrations did not change. Systolic blood pressure also rose significantly. Underfeeding resulted in reductions in noradrenaline appearance and clearance rates and in the T3 level. These results demonstrate that sympathetic nervous system activity, as determined by noradrenaline turnover in plasma, varies in response to short-term changes in energy intake in normal weight subjects. These changes may partly explain why some individuals maintain body weight constant despite large differences in food intake. The present findings may also be relevant to the variability in susceptibility to become obese.

The peripheral kinetics of norepinephrine in depressive illness

Sympathetic nervous system function was studied in patients with primary depressive illness. Tritiated norepinephrine was used to measure the rate of entry to plasma of norepinephrine released from sympathetic nerves ("norepinephrine spillover rate"), and to assess the neuronal uptake of norepinephrine by studying the removal of norepinephrine from plasma. Norepinephrine spillover was elevated in five of 11 patients. This abnormality, which was unrelated to the presence of individual vegetative symptoms, occurred exclusively in patients with endogenous depression. The rapid-removal phase of the disappearance of tritiated norepinephrine from plasma, which seemed to correspond with neuronal uptake of norepinephrine, was accelerated in patients with depressive illness, providing presumptive evidence of increased neuronal uptake. If norepinephrine uptake is also accentuated within the brain, a functional deficiency of the transmitter at adrenergic receptor sites might result.

Biochemical quantification of sympathetic nervous activity in humans using radiotracer methodology: fallibility of plasma noradrenaline measurements

We have developed radiotracer techniques for studying noradrenaline kinetics, to assess better sympathetic nervous system function in humans. Tritiated l-noradrenaline was infused intravenously (0.35 microCi/m2/min) to plateau plasma concentration. Noradrenaline plasma clearance was calculated from plasma tritiated noradrenaline concentration at steady state, and the rate of spillover of noradrenaline to plasma derived from plasma noradrenaline specific radioactivity. Mean noradrenaline spillover at rest in 34 normal subjects was 0.33 micrograms/m2/min (range 0.17-0.61 micrograms/m2/min). Predictably, noradrenaline spillover was reduced in patients with subnormal sympathetic nervous system activity, 0.16 +/- 0.09 micrograms/m2/min in eight patients with idiopathic peripheral autonomic insufficiency, and 0.11 +/- 0.07 micrograms/m2/min (mean +/- SD) in six patients with essential hypertension treated with clonidine (0.45 mg daily). Noradrenaline line plasma clearance in normal subjects was 1.32 +/- 0.28 L/m2/min. Clearance fell with age, causing the previously described rise in plasma noradrenaline concentration with aging. Unexpected effects of drugs were encountered, for example chronic beta-adrenergic blockade in patients with essential hypertension reduced noradrenaline clearance. Plasma noradrenaline concentration measurements were not in agreement with noradrenaline release rate values, and do not reliably indicate sympathetic nervous system activity, in instances such as these where noradrenaline clearance is abnormal.

Effect of propranolol on noradrenaline kinetics in patients with essential hypertension

1 The rates of noradrenaline spillover to, and removal from, plasma were measured in ten patients with essential hypertension treated with propranolol, to ascertain if long-term administration of this drug reduces sympathetic nervous system tone. 2 The plasma clearance of noradrenaline fell with propranolol, leading to a small rise in the mean plasma noradrenaline concentration. Sympathetic nervous activity in treated patients cannot be reliably gauged from plasma noradrenaline values because these are distorted by the reduction in noradrenaline clearance. 3 There was no consistent effect on noradrenaline spillover rates, which fell in six patients, but rose in the remaining four. The magnitude of the antihypertensive response was unrelated to these changes in noradrenaline release. During propranolol treatment, noradrenaline spillover rates were in every case within the normal range, much higher than in patients treated with the known sympathetic nervous systems suppressant, clonidine. 4 The principal mode of antihypertensive action of propranolol is something often than central suppression of sympathetic tone or pre-synaptic inhibition of noradrenaline release.

Differing noradrenaline kinetics in essential hypertension and depressive illness, two diseases in which the plasma concentration of noradrenaline is sometimes elevated

1. The rate of spill-over of noradrenaline to plasma, and neuronal noradrenaline uptake, which influences spill-over, were studied in patients with essential hypertension and depressive illness. 2. Noradrenaline spill-over was increased in seven of thirty-four patients with essential hypertension and five of eleven patients with primary depressive illness, compared with values in seventeen normal subjects (range 1.0-3.63 nmol/min per m2). 3. Faulty neuronal reuptake of noradrenaline seemed to be the cause of higher noradrenaline spill-over in patients with essential hypertension. Increased sympathetic nerve firing rates apparently were responsible in the primary depressives, despite their normal blood pressure. 4. These puzzling findings suggest that hypertension occurs when neurotransmitter excess is due to defective noradrenaline reuptake (in essential hypertension), but not chronically increased nerve firing (in depressive illness).

Norepinephrine kinetics in essential hypertension. Defective neuronal uptake of norepinephrine in some patients

To assess sympathetic nervous system function in essential hypertension, we measured the rates of release to and removal from plasma of the sympathetic neurotransmitter, norepinephrine. In normal subjects, disappearance of tritiated l-norepinephrine from plasma, after infusion to steady state, was biexponential, with t1 1/2 = 2.0 +/- 0.4 minutes (mean +/- standard deviation) and t2 1/2 = 33 +/- 15 minutes. The rapid component of removal seemed to represent neuronal uptake of norepinephrine: the t1 1/2 was lengthened by the selective inhibitor of neuronal norepinephrine uptake, desipramine; it was not changed by the extraneuronal uptake blocker, cortisol; and it was prolonged in patients with peripheral sympathetic nerve dysfunction (idiopathic autonomic insufficiency). In eight of 37 hypertensive patients, the t1 1/2 was greater than 2.8 minutes (range, 3.3-6.0 min), longer than in any normal subject; this appears to be presumptive evidence of the existence of defective neuronal norepinephrine uptake. In these patients the rate of spillover of norepinephrine to plasma, of transmitter escaping uptake after release, was 0.73 +/- 0.39 micrograms/m2/min (4.3 +/- 2.3 nmoles/m2/min), higher than in normal subjects, 0.36 +/- 0.14 micrograms/m2/min (2.1 +/- 0.8 nmoles/m2/min) (p less than 0.01). A defect in neuronal uptake of norepinephrine, by exposing adrenergic receptors to high local norepinephrine concentration, may be important in the pathogenesis of blood pressure elevation in some patients with essential hypertension.

Age-dependence of noradrenaline kinetics in normal subjects

1. The influence of age on the rate of spillover of noradrenaline into plasma, clearance of noradrenaline from plasma, and plasma noradrenaline concentration at rest was studied in 34 healthy subjects aged 20--69 years. 2. The plasma concentration of noradrenaline was dependent on age, values being higher in older subjects. 3. This age-dependence of plasma noradrenaline concentration was due principally to a reduced clearance of noradrenaline from the circulation in older subjects. 4. The rate of spillover of noradrenaline into plasma was little influenced by age. The higher plasma noradrenaline values found in older subjects do not seem to be due to an increase in sympathetic nervous system tone with aging.

Effect of norepinephrine uptake blockers on norepinephrine kinetics

We studied the effect of a single oral dose of the neuronal norepinephrine uptake blocker, desipramine 125 mg, on norepinephrine kinetics. Desipramine reduced the plasma norepinephrine clearance by approximately 20%, from 1.33 +/- 0.22 to 1.08 +/- 0.19 l/m2/min (p less than 0.01). Similarly, plasma norepinephrine clearance was slowed in patients with sympathetic nerves damaged by disease (idiopathic peripheral autonomic insufficiency). Desipramine also reduced the rate of spillover of norepinephrine to plasma, 0.27 +/- 0.07 to 0.15 +/- 0.04 micrograms/m2/min, leaving the plasma norepinephrine concentration unchanged. Disappearance of tritiated norepinephrine from plasma, after infusion to steady state, was biexponential, with half-time of the rapid-removal phase (t1 1/2) = 2.0 +/- 0.4 min and half-time of the second exponential (t2 1/2) = 34 +/- 10 min. The rapid-removal phase was sensitive to disturbances in the neuronal uptake of norepinephrine, the t1 1/2 being prolonged by desipramine and lengthened in the patients with peripheral autonomic insufficiency. In contrast, the selective extraneuronal norepinephrine uptake blocker, cortisol, 500 mg intravenously, had no effect in normal subjects on either plasma norepinephrine clearance or the t1 1/2 value. Neuronal uptake of norepinephrine contributes to the overall removal of norepinephrine from plasma. Extraneuronal uptake of norepinephrine could not be demonstrated at existing plasma norepinephrine concentrations.

Sister chromatid exchange in aplastic anemia

The incidence of sister chromatid exchanges (SCE) in the lymphocytes of patients with aplastic anemia (AA) was determined before and after exposure to mitomycin C (MMC). The "baseline" SCE rate was significantly higher in AA, but MMC-induced SCE rate was not different compared to controls. It is suggested that some patients with AA may have an underlying DNA damage.

Determination of noradrenaline uptake, spillover to plasma and plasma concentration in patients with essential hypertension

1. The rates of entry of noradrenaline to plasma and of removal of noradrenaline from plasma, and plasma noradrenaline concentration, were determined in normal subjects and in patients with essential hypertension. Neuronal uptake of noradrenaline was assessed from the plasma tritiated noradrenaline disappearance curve, after infusion to steady state. 2. Noradrenaline disappearance was biexponential. Rapid removal was dependent on neuronal uptake, being slowed if neuronal noradrenaline uptake was reduced, either by desipramine in normal subjects, or in patients with sympathetic nerve dysfunction (autonomic insufficiency). 3. In 10 of 41 hypertensive patients the t 1 1/2 similarly was prolonged, presumptive evidence of a defect in neuronal noradrenaline uptake. Endogenous noradrenaline escaping uptake after release, and spilling over into plasma, and plasma noradrenaline concentration, were increased in these patients. 4. Defective neuronal uptake of noradrenaline, by exposing adrenoreceptors to high local transmitter concentration, may be important in the pathogenesis of essential hypertension in some patients.

Assessment of neuronal uptake of noradrenaline in humans: defective uptake in some patients with essential hypertension

1. Disappearance of tritiated noradrenaline from plasma, after infusion to steady-state, was studied to assess neuronal uptake of noradrenaline inessential hypertension. 2. Plasma tritiated noradrenaline disappearance was biexponential. Rapid removal was dependent on neuronal uptake, being slowed both in normal subjects after desipramine, and in patients with sympathetic nerve dysfunction (autonomic insufficiency). 3. In nine of thirty-eight hypertensive patients the t1/12 similarly was prolonged. Endogenous noradrenaline escaping uptake after release, and spilling over into plasma, was increased in these patients. 4. Defective neuronal uptake of noradrenaline, by exposing adrenergic recepotors to high local transmitter concentration, may be important in the pathogenesis of essential hypertension in some patients.

Nonaphasic misnaming and other neurobehavioral features of an unusual toxic encephalopathy: case study

A patient with propranolol-induced mental status changes was studied during and after the period of propranolol intoxication. While intoxicated he manifested the syndrome of "non-aphasic misnaming," did poorly on the nonverbal portions of the WAIS, and exhibited perseveration and variability of performance. Our observations clarify the nature of the neurobehavioral disturbances in toxic-metabolic encephalopathies.

Tricyclic antidepressants: potent blockade of histamine H1 receptors of guinea pig ileum

Six tricyclic antidepressants were tested for their ability to antagonize histamine actions at histamine H1 receptors in a bioassay for these receptors (histamine-induced contractions of guinea pig ileum). All compounds were competitive antagonists with equilibrium dissociation constants in the range of 5.6 x 10(-11) M to 1.5 x 10(-7) M. Doxepin hydrochloride and amitriptyline hydrochloride were the most potent compounds of the series and may be the most potent antihistamines known. Antagonism at histamine H1 receptors by these compounds may explain their sedative effects.

[Indications and limitations of surgery of the sympathetic nervous system (author's transl)]

Two types of sympathectomy are common today, the lumbar and the cervicothoracic. It is a simple operation with extremely low mortality and morbidity although the patients are frequently of an advanced age. 8--10 days after the operation pains may occur, especially at night. The authors observed them in 3--15% of cases after lumbar sympathectomy, more rarely after cervicothoracic sympathectomy. The pains usually disappear after a few weeks or months. Sexual disturbances may occur in about 10--15% of young men. Therefore in these patients the first two lumbar ganglia should be spared. Arterial obstructions above all arteriosclerotic occlusions are the most important and most frequent indications for surgery of the sympathetic nervous system. Statistics from the Strasburg Hospital yielded a total of 56% good and very good results in 666 lumbar sympathectomies, and 31.2% successes even in Fontaine's stage IVa.

Heritable fragile sites on human chromosomes. IV. Silver staining

The chromosomal gaps associated with fragile sites at 2q11, 10q23, 11q13, 16q22, 20p11 and Xq27 do not stain with silver nitrate as do NOR regions of the acrocentric chromosomes.