Hypotensive and antiplatelet actions of motapizone depend on dose and time after ingestion

Single doses of motapizone 1 to 10 mg were given to 12 healthy subjects. Before and up to 8 h after each dose the blood pressure and heart rate were measured, as well as thrombocyte aggregation "ex vivo" with collagen, ADP and adrenaline. Motapizone produced a dose-dependent reduction in diastolic blood pressure and an increase in heart rate. These effects were demonstrated with individual variations after 1 to 3 mg and as a rule they were very marked after more than 6 mg. With the highest dose (mean 7.7 +/- 2.3 mg) the diastolic pressure fell by an average of 23% 1 h after medication as compared to with the baseline values. At the same time there was marked inhibition of thrombocyte aggregation, which also became apparent after about 3 mg and increased in proportion to the dose. The inhibition of aggregation peaked after 2 h and had disappeared within 8 h. The inhibition of ADP-induced aggregation was particularly marked.

Inhibition of thrombocyte aggregation by oral motapizone and other drugs

Ten healthy subjects took single oral doses of placebo, 8.8 +/- 1.8 mg motapizone, 40 +/- 13 mg captopril, 25 mg dihydralazine, 20 mg nifedipine and 4.5 +/- 1.1 mg prazosin in random order, and, as the last preparation 500 mg acetylsalicylic acid. Thrombocyte aggregation induced "ex-vivo" with collagen, ADP and adrenaline was measured before and after 60 min. Immediately before each dose, the "threshold concentration" of each agent was determined in each subject, i.e. the concentration producing about 90% of maximal aggregation. After the preparation had been taken, aggregation was induced with 1-, 2- and 4-times the threshold concentration. Both motapizone and also acetylsalicylic acid caused marked inhibition of aggregation at up to 4-times the threshold concentration; the dose ratio was about 1:50. Motapizone produced greater inhibition of the aggregation induced by ADP and acetylsalicylic acid than of that due to collagen. The inhibitory actions after captopril, dihydralazine, nifedipine and prazosin were weak and did not significantly differ from placebo.

Hypotensive efficacy of a mixed solution of 0.1% sodium nitroprusside and 1% sodium thiosulphate

A mixed solution of 0.1% sodium nitroprusside and 1% sodium thiosulphate ('SNP-thiosulphate') was given as i.v. infusion to 80 patients, 30 of whom were hypertensive emergencies and 50 were surgical cases requiring induction of hypotension. This treatment lowered the blood pressure (BP) by an average of 30% of the initial levels in the hypertensive patients and 30-40% of the initial levels in the surgical patients. The mean effective dose in the hypertensive patients was 2.4 micrograms/kg/min compared with about 3 micrograms/kg/min in 40 cases treated with sodium nitroprusside as mono-infusion. For deliberate hypotension in surgical patients the mean doses of SNP, used here in the mixed infusion with thiosulphate, were 1.0 and 2.3 micrograms/kg/min, compared with 1.3-7.5 micrograms/kg/min in 181 patients treated with SNP as monotherapy. In contrast to conventional therapy with SNP, the infusion of SNP-thiosulphate even at extremely high dose rates did not produce toxic concentrations of prussic acid in the blood. In no case was a rise observed in the cellular enzymes as an indirect indication of hypoxic cell damage. SNP-thiosulphate is thus at least as effective at lowering BP as SNP infused alone, and has a substantially lower toxicity risk.

Clinical pharmacokinetics of nitroprusside, cyanide, thiosulphate and thiocyanate

Sodium nitroprusside decomposes within a few minutes after intravenous infusion to form metabolites which are pharmacologically inactive but toxicologically important. Free cyanide, which represents 44% w/w of the sodium nitroprusside molar mass, is formed and must be detoxified in the body into thiocyanate using thisulphate as substrate. Nitroprusside penetrates cell membranes slowly. At therapeutic dose levels its distribution is probably mainly extracellular. Contact with the sulfhydryl groups in the cell walls, however, immediately initiates breakdown of the molecule. Sodium nitroprusside taken orally is not absorbed from the gastrointestinal tract to any appreciable extent. Cyanides in the body form prussic acid, which can rapidly penetrate mucous and cell membranes. In the blood, about 99% of the prussic acid binds to the methaemoglobin of erythrocytes. At normal physiological levels, however, the total body methaemoglobin of an adult human can only bind about 10mg of prussic acid; this is a small fraction of the amounts usually infused therapeutically as sodium nitroprusside. The endogenous detoxification of prussic acid exhibits zero-order kinetics. The limiting factor is a sulphur donor, principally thiosulphate, which is available in the body in only limited amounts. The rate of spontaneous detoxification of prussic acid in humans is only about 1 microgram/kg/min, corresponding to a sodium nitroprusside infusion of about 2 microgram/kg/min. This dose limit set by the prussic acid toxicity of sodium nitroprusside can, however, be increased considerably by simultaneous infusion of thiosulphate. A lack of thiosulphate can be detected early by a rise of the prussic acid concentration in the erythrocytes. Thiosulphate taken orally is not absorbed by the body. After intravenous infusion, its serum half-life is about 15 minutes. Most of the thiosulphate is oxidised to sulphate or is incorporated into endogenous sulphur compounds; a small proportion is excreted through the kidneys. Thiocyanate taken orally is completely absorbed by the body. In healthy persons its volume of distribution is approximately 0.25 L/kg and the serum half-life about 3 days; elimination is mainly renal. Thiocyanate toxicity does not represent a serious therapeutic problem with intravenous infusion of sodium nitroprusside.

An embryotoxicity study of the fungicide tridemorph and its commercial formulation Calixin

Tridemorph (N-tridecyl-2,6-dimethylmorpholine), the active ingredient of the commercially formulated fungicide Calixin, is a teratogen in rats and mice. The no-effect level for embryotoxic effects was 27.5 mg/kg for mice and 20.6 mg/kg for rats. By contrast, when Calixin, which contains 83% tridemorph, was administered orally at dose levels of 0.156, 0.722, and 3.909 mg/kg, no embryotoxic effects were observed in two strains of rats. Our extensive investigations, carried out under exposure conditions resembling as closely as possible those reported in another study, did not reproduce the previous findings of teratogenicity of Calixin.

[Treatment of ergotism]

Ergotism occurs in patients so disposed, particularly under ergotamine therapy for migraine. The principal signs are arterial spasms in the legs, or sometimes also the arms, which can lead to gangrene. Intravenous or intra-arterial infusion of sodium nitroprusside or nitroglycerine has proved the only reliably efficacious therapy. The best results have been obtained using nitroprusside: twelve cases are described here. By contrast, nonefficacious measures include, in particular, sympathetic blockade.

Lung metastasis of a meningioma

Case report of a 35-year-old male patient. 1976: operation for a falx-meningioma. 1981: meningioma recurrence and further intracranial meningiomas.

HISTOLOGY

1976 and 1981 endotheliomatous meningioma: no signs of malignancy. Prior to the 2nd operation in 1981 a lung tumor was diagnosed for the first time. HISTOLOGY of the lung tumor: endotheliomatous meningioma, same histology as in cerebral meningiomas.

[The therapeutic scope of sodium nitroprusside]

Sodium nitroprusside (SNP) as a monoinfusion was administered to 50 patients for periods of a few hours. A further group of 20 patients received SNP for periods of several days as a combination solution, of SNP mixed with sodium thiosulphate. Infusion of SNP on its own at levels exceeding 2 micrograms/kg/min led to cyanide levels in the blood rising proportional to dosage. Infusion of SNP mixed with thiosulphate showed no such accumulation. This procedure is free of danger and should become the technique of choice when therapeutically administering SNP to lower blood pressure.

[Resorption of hydrocyanic acid from linseed]

Resorption of hydrocyanic acid after ingestion of linseed was investigated in 20 healthy volunteers and 5 patients. The persons investigated took a single dose of 30 g or of 100 g of linseed or they received throughout several weeks 15 g. t.i.d. One volunteer also took for purposes of comparison bitter almonds or potassium cyanide. Before, during and after the periods of ingestion plasma levels of hydrocyanic acid and of thiocyanate were normal. During long-term trials urinary excretion of thiocyanate was monitored regularly. Intake of linseed even in extremely high dosages never caused significant rises of plasma thiocyanate levels; this, however, was the case after intake of bitter almonds or potassium cyanide. Thus, it can be excluded, that intoxication by hydrocyanic acid can be caused by linseed. Long-term intake of linseed however, raised plasma levels of thiocyanate significantly; at the same time urinary excretion of thiocyanate increased.

Cyanide toxicity of sodium nitroprusside in therapeutic use with and without sodium thiosulphate

Sodium nitroprusside (SNP) as a mono-infusion was administered to 51 patients for periods of a few hours. A further group of 19 patients received SNP for periods of several days as a combination solution of SNP mixed with sodium thiosulphate. The concentrations of cyanide and of thiocyanate in the blood of all patients were measured. In seven of the patients the level of thiosulphate was also measured. Infusion of SNP on its own at levels exceeding 2 microgram/kg/min led to the rising of cyanide levels in the blood being proportional to dosage. Infusion of SNP mixed with thiosulphate showed no such accumulation of cyanide in any patient, irrespective of dosage level and duration. The efficacy at lowering blood pressure was fully maintained in the mixed infusion. The elimination half-life for thiosulphate was 16.5 min. Pharmacokinetic calculation of the rise in cyanide level showed that mono-infusions of 5-10 micrograms SNP/kg/min could within 5-10 h cause a life-threatening cyanide level in the blood. By contrast, mixed infusion of SNP together with thiosulphate, for which light-opaque syringes and tubing must be used, is a procedure free of danger and should become the technique of choice when therapeutically administering SNP in order to lower blood pressure.

Detoxification of cyanide in a new-born child

A well-developed male baby was given infusions of 2-5 microgram/kg/min of sodium nitroprusside (SNP) in the first few days after birth on account of high arterial blood pressure. After 30 h of treatment, cyanide accumulation was found to have reached a life-threatening level. IV administration of 100 mg/kg of sodium thiosulphate promptly lowered the cyanide level. The mixed infusion of SNP together with thiosulphate, used in the subsequent course, was no longer toxic.

[Management of treatment-resistant hypertension: comparison of the antihypertensive effect of endralazine and minoxidil (author's transl)]

In 16 fo 20 patients with treatment-resistant hypertension endralazine, combined with beta-receptor blockers and diuretics, significantly lowered mean arterial blood pressure from 198/112 mmHg to 148/88 mmHg. The initial dose of endralazine was 2.5 mg three times daily. After this the dosage was increased, at the three to six-day intervals according to antihypertensive action and side effects, to a maximum of 50 mg daily in steps of 5.0--7.5 mg per dose. - In a second series of eleven additional patients with treatment-resistant renal hypertension the blood-pressure lowering effect of hydralazine and minoxidil was compared in an open cross-over trial. The result was in favour of hydralazine. Sodium and water retention was slightly less marked with endralazine. Sleep disorders, increased frequency of feeling cold, moderately severe flushing with red checks and feeling hot occurred but rarely with endralazine and regressed during the period of observation.

Cytometric investigations in histochemically identified neurons--changes of fluorescence intensities and nuclear diameters in dopamine neurons of the arcuate nucleus in the cycling rat

The relative formaldehyde-induced fluorescence intensities and the diameter of cell nuclei of fluorescent perikarya of the arcuate nucleus were recorded in serial cross-sectioned hypothalamic arcuate nuclei of regularly cycling rats (5 estrous and 4 proestrous animals). Stress-induced changes of cytometric parameters were avoided by preadaptation of animals to handling procedures. Dopamine neurons in a 75 micrometer thick periventricular layer of the arcuate nucleus exhibited significantly smaller nerve cell nuclei and significantly reduced relative fluorescence intensities in proestrous rats. Both of these cytometric parameters indicate a decrease in the activity of periventricular dopamine neurons of the arcuate nucleus. The reported findings might support the hypothesis that dopamine inhibits the release of LH-RH.

Counteraction of cyanide poisoning by thiosulphate when administering sodium nitroprusside as a hypotensive treatment

A 42-year old patient received a continuous infusion of sodium nitroprusside (SNP) at a dosage rate of 600 microgram/min for approximately four days. On the third day of treatment a dangerous high level of cyanide was measured in the blood. When an additional continuous infusion of sodium thiosulphate at five times the molar concentration of the SNP was given, this cyanide level dropped over a period of 7h to one-seventh of its initial value. The thiosulphate did not reduce the effectiveness of the SNP in lowering the blood pressure.

[Polychemotherapy of inoperable bronchogenic carcinoma: preliminary results (author's transl)]

Preliminary results indicate that BACO and SAKK are capable of inducing remission in 80-90% of cases of small-cell bronchogenic carcinoma; these remissions last for about 6 months and not only prolong, but improve the quality of, life. In view of the small number of cases so far observed no assessment can as yet be made of the superiority of one or the other method concerning the incidence and duration of remissions and survival time. In cases of squamous cell cancer the two therapeutic methods succeeded in only 30-40% of the patients in inducing partical remissions and they did not appear to improve the quality of life. The question whether the treatment actually prolongs life as compared with the natural course of the disease remains open.

[Early diagnosis of small airways disease in young smokers (author's transl)]

Investigations during the past years have established that determinations of closing volume, flow-volume curves and frequency-dependent compliance are capable of detecting pathological changes in the bronchial system at a time when the customary lung function tests (FEV1.0 resistance as measured by bodyplethysmography) are still normal. These observations have been made use of to diagnose incipient damage in persons exposed to bronchial noxae. In the present investigation the effect of smoking on the airways was studied in a group of 25 persons aged 20-25 years by determining the closing volume and differences in ventilatory distribution (Thews method). The results were compared with those obtained in a group of 27 non-smokers in the same age group.

Kinetics of elimination of thiocyanate in 7 healthy subjects and in 8 subjects with renal failure

The concentration of thiocyanate in the serum of eight test subjects with renal failure and seven healthy control subjects was measured, as it declined with time, after oral doses of thiocyanate or i.v. injections of nitroprusside had been administered. Additional measurements were taken, on the healthy subjects only, of the concentrations of thiocyanate in the urine, and also of the influence of an increased chloride intake on the rate of elimination of thiocyanate. For the healthy subjects an elimination half-life of between one and five days (mean c. 3 days) was found. Increasing the chloride elimination rate to approximately twice normal did not significantly speed up the rate of thiocyanate elimination. The amounts of thiocyanate which had been administered as doses reappeared almost exclusively in the urine. For the subjects with renal failure, the elimination half-life had a mean value of approximately nine days. The elimination constants were found to be proportional to the creatinine-clearance rates. The ke value at a creatinine-clearance of zero ml/min was approximately 15% of the ke value at a creatinine-clearance rate of 120 ml/min. The distribution volumes for thiocyanate were greater for the patients with renal failure than for the healthy subjects. The conclusions for therapies using nitroprusside are discussed.

[Pathological and roentgenographic morphology in different stages of pulmonary shock (author's transl)]

Pulmonary shock syndrome may be better understood by comparing morphological and patho-physiological alterations in different stages. In the very early stage only fine structural tracer studies in experimental animals elicit morphological alterations of the microcirculation in the alveolar wall. These findings can be related to changes of ventilatory and blood-gas parameters. After a short interval microscopic and radiological features correspond. Interstitial pulmonary edema is the main syndrome of shock lung.

[Desquamative interstitial pneumonia. Peripheral eosinophilia in DIP: a new clinical aspect (author's transl)]

It were Liebow et al. (1965) who, for the first time, described the desquamative interstitial pneumonia (DIP) as one clinical and morphological unit. The etiopathology of this disease is still unknown and there exist many controversial opinions as to its role within the interstitial pneumonias. For the clinical-physician the DIP represents a difficult problem because there seems to be no uniform appearance to this disease. So a lung-biopsy is the unique way to make a definitive diagnosis. The following description represents a case of DIP observed at our hospital. At the same time we tried to give a review of our present knowledge concerning the morphology, course and therapy of this disease. We think it should be note that the DIP was accompanied by an extreme peripheral eosinophilia. To our knowledge this is the first time such a phenomenon is described. In the course of the treatment with steroids the eosinophilia disappeared parallel to the normalization of the radiographic findings.

[Cardio-pulmonary parameters after myocardial infarction in the late period of recovery. Investigation at rest and during exercise (author's transl)]

From 22 patients in the late period of recovery from myocardial infarction, cardio-pulmonary data were recorded at rest and during exercise. The physical work was increased stepwise until patients reached their individual limit of exercise. According to the different work capacity four groups of patients were formed with the aim to demonstrate the adaption processes of cardio-pulmonary parameters until reaching the peak of work capacity. In one half of the patients we still found signs of cardial insufficiency at rest. After only slight physical work signs of cardiac insufficiency appeared also in the other half of patients.

[Pulmonary gas exchange after myocardial infarction in the late period of recovery. I. Investigation at rest]

In the late period of recovery after myocardial infarction (13-25 months p. infarctum) lung function of 23 patients was examined at rest. Spirometric values and parameters of pulmonary gas exchange showed alterations caused by pathological left ventricular function. Arterial Po2 was slightly decreased (chi=74.5 +/- 5.9 Torr), AaDo2 (chi=33.6 +/- 7.7 Torr) and aADco2 (chi=8.6 +/- 3.7 Torr) were increased. Pathological changes of arterial Pco2 (chi=40.6 +/- 2.5 Torr) were not observed. Mixed venous Po2 and cardiac output in 9 patients suggested cardiac failure. In a number of pulmonary parameters measured at rest correlations could prove a dependence on the patients physical work capacity.