Urine dopamine during normotensive and hypertensive pregnancies and the puerperium

Urinary excretion of dopamine, sodium and creatinine have been studied during pregnancy and the puerperium in three groups of women, normotensive, pre-eclamptic and those exhibiting gestational hypertension. Differences in the pattern of dopamine and salt excretion are evident in the two hypertensive groups and lend support to the concept that women who develop gestational hypertension have a defect in the mobilisation of dopamine similar to that observed in males with essential hypertension.

The effect of dietary sodium chloride and gamma-glutamyl dopa on tubular necrosis following glycerol administration in the rat

The protective effect of a high dietary sodium intake in models of acute renal failure is well known. This effect may be mediated via an increased endogenous dopamine production. The effects of different salt intakes and υ-glutamyl dopa (a renal pro-drug for dopamine) on the histological changes following s.c. glycerol were studied in the rat. The protective effect on a high sodium diet was confirmed and υ-glutamyl dopa was also shown to reduce significantly the damage caused by glycerol.

Dopamine and the kidney

It would seem established beyond peradventure that dopamine is formed in the kidney from circulating L-dopa. The likely site would appear to be the renal tubular cells but the contribution of the renal dopaminergic nerves needs further evaluation. Moreover it is probably that dopamine formed within the kidney acts there on specific receptors. This results in vasodilatation of renal blood vessels, by action on vascular receptors, and natriuresis, by an effect on tubular sodium transport mechanisms. Dopamine may form an integral part of the renal natriuretic cascade by, in its turn, evoking both the kallikrein-bradykinin system and the production of renal prostaglandins. Specific activation of the renal dopaminergic system by the administration of suitable agonists or renal prodrugs may prove possible in the future. Abnormalities in the renal production of dopamine may be important in several hypertensive and oedematous disorders. Further work will be required to establish a possible role for dopamine in these conditions and to determine whether they will benefit from treatment with suitable dopamine agonists. Dopamine, once regarded as of little importance outside the central nervous system, has certainly come to occupy a central place in renal salt handling. The ratio of dopamine production in the kidney to that for renin may be of pivotal importance in the control of systemic arterial pressure.

Reversible developmental change in the ability of ciliary ganglion neurons to extend neurites in culture

From stages 35 to 40 in the chicken embryo, ciliary ganglion neurons undergo a developmental change which is detected in our assay system as a marked decline in the ability to extend neurites when placed in culture. This developmental loss is observed when the neurons are placed in culture as single, dissociated cells or as undissociated ganglion explants. The loss of the ability to extend neurites in culture is not a transitory phenomenon, for no recovery of this ability is observed during the rest of embryonic development or posthatching. There is a close temporal correlation between the embryonic period during which the ability of ciliary ganglion neurons to extend neurites declines and the period (stages 35 to 40) when these neurons form functional peripheral synapses in the embryo. The ability to extend neurites rapidly is not recovered during normal development as long as the ganglion and its connections within the organism remain intact. However, if the ciliary ganglia are removed from a stage 40 embryo and cultured for 3 to 4 days before being dissociated, the neurons have largely recovered their ability to initiate neurite outgrowth rapidly. This recovery after removal from the embryo is also presumably responsible for the eventual dense outgrowth of neurites from stage 40 ganglion explants after a 3- to 4-day delay in culture. Our results, in conjunction with similar results from other systems, suggest a cause and effect relationship between the establishment or disruption of peripheral connections and the loss or recovery, respectively, of the ability to extend neurites rapidly.

Urine dopamine in normal and hypertensive pregnancies

Dopamine output in urine was determined in two groups of women with hypertension in pregnancy. A highly significant elevation of urine dopamine was detected in those women with pre-eclampsia compared with that in matched control subjects. In contrast, no difference in urine dopamine output was detected between a group of multigravidae with hypertension in pregnancy and matched control subjects.

Biochemical indices of response to hydroxychloroquine and sodium aurothiomalate in rheumatoid arthritis

Biochemical and clinical changes have been monitored in 30 patients with rheumatoid arthritis treated with either hydroxychloroquine or sodium aurothiomalate over a period of 6 months. Acute-phase reactants improved in both treatment groups, while serum sulphydryl and serum histidine improved only in the gold-treated patients. Correlation matrices were constructed from mean clinical and biochemical data at successive clinic visits. Correlations obtained with gold were more frequent and of a higher level of significance than those obtained with hydroxychloroquine at the doses we studied. This lends support to the use of correlation matrices as a screening test for potential long-term antirheumatoid activity of drugs in man.

Urine free dopamine in normal primigravid pregnancy and women taking oral contraceptives

1. Urine free dopamine was estimated at predetermined points of the menstrual cycle in normal volunteer subjects and in women taking a combined oral contraceptive. 2. There was no alteration in 24 h urine dopamine during the normal menstrual cycle but, in contrast, combined oral contraceptives produced a fall which recovered premenstrually. 3. In 19 primigravid subjects 24 h urine free dopamine was estimated at monthly intervals throughout pregnancy and at the time of the postnatal examination. 4. Urine dopamine was elevated throughout pregnancy when compared with postnatal values. Women receiving an oral progestogen contraceptive at the time of the postnatal examination showed a further fall in urine dopamine.

Discriminatory indices of response of patients with rheumatoid arthritis treated with D-penicillamine

A long-term study is being undertaken to classify drugs used as specific agents in the treatment of rheumatoid arthritis in terms of their effects on biochemical and clinical characteristics of the disease. In particular is hoped to establish those indices which are most relevant to the response of RA to treatment. Fifteen patients were treated with D-penicillamine after an initial period of 2 weeks on aspirin alone, when the baseline investigations were made. The dose of penicillamine was increased gradually to a maximum of 500 mg a day over the period of 6 months, and changes in 8 clinical and 25 laboratory indices were measured on 8 separate occasions in the 6-month period. Marked clinical improvement took place, and this was mirrored by changes in a wide range of biochemical parametaers. ESR and C-reactive protein were shown to be the most suitable indices of disease improvement with penicillamine treatment.

A biochemical comparison of alclofenac and D-penicillamine in rheumatoid arthritis

In view of the claim that alclofenac has a specific antirheumatoid action a detailed biochemical study has been made over a 6-month period of 2 groups of patients with rheumatoid arthritis receiving either alclofenac or D-penicillamine for the first time. We found no biochemical evidence and little clinical evidence that alclofenac had a 'penicillamine-like' effect in rheumatoid arthritis.

The effect of mineralocorticoid administration on urine free dopamine in man

1. Five normal subjects were studied under metabolic conditions on a controlled sodium and potassium intake. 2. Plasma and urine free dopamine concentrations were measured in these subjects before, during and after 5 days administration of fludrocortisone (0.2 mg twice daily). 3. Urine free dopamine showed a tendency to fall during the early phase of fludrocortisone administration and then rose towards normal. 4. In a patient with primary hyperaldosteronism there was no evidence of increased renal production of dopamine. Urine dopamine fell when plasma renin activity rose as a result of spironolactone administration (200 mg three times a day for 5 days). 5. If renal dopamine has a role in mineralocorticoid 'escape' then it may be permissive only. The mechanisms of control of dopamine production could include tubular sodium concentration, tubular chloride concentration and intrarenal renin activity.

Mastomys (=Praomys) natalensis is not a Rattus (Mammalia: Rodentia): karyological evidence

Certain past studies have suggested that the taxa Mastomys (= Praomys) and Rattus were closely allied phyletically. We here present detailed (C- and G-banding and NOR's) comparisons of the karyotypes of M. natalensis (2n = 36) and R. norvegicus (2n = 42). A standardized G-banded karyotype of M. natalensis is also presented. About 45% of the G-banded karyotype of M. natalensis is homologous with that of R, norvegicus. Autosomal constitutive heterochromatin is nearly equivalent in the two species; the X and Y chromosomes of M. natalensis, however, have exceptionally large heterochromatic segments. Both species possess three pairs of NOR's, but adjacent G-banded regions are homologous for only one of these. Primarily on the basis of overall G-band homology, we regard the two taxa as only distantly related.

Yeast stimulation of bone marrow mitosis for cytogenetic investigations

We report a simple, dependable method for stimulating bone marrow mitosis in small mammals. Subcutaneous injections of a suspension of active baker's yeast may elevate the mitotic index as much as six times or more. Additionally, the metaphases obtained are easily spread when air dried, and the chromosomes are readily banded. This method should prove useful to investigators who wish to use bone marrow as a source of chromosomes for cytotaxonomic studies or for studies of specific chromosome damage in vivo.

Two cases of the nephrotic syndrome with a reversible coagulation defect

Two cases of the nephrotic syndrome with an apparently identical defect of blood coagulation, discovered during preparation for renal biopsy are described. Plasma from both patients showed prolongation of thrombin and kaolin cephalin times which was probably due to abnormally slow polymerization of fibrin monomer. Corticosteroid therapy reversed the abnormal times in one case. One of the patients showed seasonal relapses which occurred in relation to episodes of hay fever associated with allergy to grass pollen. The other patient showed some similar features, but on renal biopsy was found to have proliferative glomerulonephritis.

Hypertension and hyperkalaemia responding to bendrofluazide

A 33-year-old man is described with hyperkalaemia, hypertension and acidosis. The blood pressure was 160 to 200 mmHg systolic and 90 to 110 mmHg diastolic and the plasma potassium was between 6.0 and 7.0 mmole per litre. There was no renal disease and creatinine clearance was 103 ml per minute. Plasma renin activity was low and plasma aldosterone was at the lower limit of normal. Sodium deprivation or oral frusemide had little effect on blood pressure, plasma potassium, renin, aldosterone or arginine vasopressin. However, bendrofluazide caused a rapid fall of blood pressure and plasma potassium, and rise of plasma renin, aldosterone and plasma arginine vasopressin. Hypertension and hyperkalaemia is rare in the absence of renal failure. Four similar patients reported previously are reviewed. We suggest that our patient, and perhaps some of those reported earlier had primary abnormality of renal tubular function with impaired secretion of potassium and excessive tubular reabsorption of sodium. The plasma renin activity could be due to volume expansion and the low plasma aldosterone was probably caused by the antagonistic effects of low renin depressing synthesis and hyperkalaemia increasing it. A minor similar tubular abnormality might be the explanation in some of the patients with essential hypertension who have low plasma renin activity.

Plasma and urine dopamine in man given sodium chloride in the diet

1. Plasma and urine free dopamine were measured daily for 5 days in six normal subjects maintained on a low sodium diet. The subjects were then given dietary supplements of sodium chloride for 5 days and the measurements repeated. 2. Throughout the experiment the 24 h free dopamine excretion rates for all the subjects were higher than could be accounted for by renal clearance. Dopamine excretion increased significantly in response to the added sodium chloride whereas plasma dopamine remained unchanged. The rise in dopamine excretion preceded that of sodium excretion. 3. It is concluded that free dopamine is formed within the kidney in response to increased dietary sodium and may have a role in the control of sodium excretion.

Urinary dopamine in man and rat: effects of inorganic salts on dopamine excretion

1. Plasma and urine free dopamine (3,4-dihydroxyphenethylamine) were measured in six normal male volunteer subjects and the urinary clearance of dopamine was calculated for each subject. 2. The excretion rates for free dopamine in man were greater than could be explained by simple renal clearance. It was concluded that free dopamine must, therefore, be formed in the kidney. 3. Changes in urinary dopamine excretion were studied in four groups of rats initially maintained on low sodium diet and then given equimolar dietary supplements of NaCl, NaHCO3, KCl or NH4Cl, to study the specificity of the previously observed increase in dopamine excretion after increased dietary NaCl. 4. The mean dopamine excretion increased significantly in rats given NaCl, KCl and NH4Cl, whereas dopamine excretion decreased in those given NaHCO3. 5. The failure of dopamine excretion to rise in response to loading with NaHCO3 was unexpected, and argues against a simple effect of volume expansion by the sodium ion. The increase in dopamine excretion with KCl and NH4Cl showed that this response was not specific to the sodium ion.