ELECTRICAL stimulation of presynaptic fibres to the so-called AH1 or type II2 myenteric neurones in guinea pig small intestine evokes a slow excitatory postsynaptic potential (e.p.s.p.) characterised by long-lasting depolarisation associated with increased membrane resistance and augmented excitability3. Two substances have been implicated as possible neurotrans-mitters for the slow e.p.s.p. Katayama and North reported that application of substance P to myenteric neurones mimicked the slow e.p.s.p.4, and J.D.W. and C.J.M. presented several lines of evidence for serotonin as the transmitter substance5,6. We now report that methysergide, a drug which abolishes both the slow e.p.s.p. and the action of exogenous serotonin5,6, does not affect the action of substance P on guinea pig myenteric neurones. The results suggest that substance P is unlikely to be the neuro-transmitter which mediates the slow e.p.s.p.

Urinary excretion of nonesterified (NEC) and total cholesterol (TC) has been investigated in 79 patients with prostatic adenoma (BPH) and 48 patients with carcinoma of the prostate. Normal range of NEC was determined in 62 healthy individuals and was found to be 0.26-2.2 mg/24 hours (2 SD) with a mean value of 0.76 mg/24 hours. TC ranged from 0.3-2.9 mg/24 hours with a mean value of 0.92 mg/24 hours. In benign prostatic hyperplasia normal values for NEC and TC were determined in stages without residual urine. In contrast patients with BPH and residual urine showed elevated NEC in 42.1% and elevated TC in 61.4%. In prostatic carcinoma NEC hyperexcretion was present in 44.8% of stage A and B and in 52.6% of stage C and D. TC was elevated in 52.2% and 63.2%, respectively. Simultaneous determination of NEC and serum acid phosphatase (SAP) gave a pathologic result of at least one parameter in 51.7% of stage A and B and in 84.2% of stage C and D. If TC and serum acid phosphatase were combined, percentage of elevated values increases to 62.1 of stage A and B and was identical with 84.2 of stage C and D. If BPH with residual urine and other known conditions of urinary cholesterol hyperexcretion in males, pluripotential malignant testicular neoplasms and diseases of kidney and urinary tract, can be excluded with reasonable certainty, both parameters may be of value in diagnosis of prostatic cancer in even early clinical stages of the disease, especially in combination with the determination of SAP.

Urinary excretion of nonesterified (NEC) and total cholesterol (TC) has been determined in 137 healthy individuals with a range (2 SD) of 0.26-2.2 mg/24 hours NEC and 0.3-3.0 mg/24 hours TC. 264 patients with various internal diseases revealed normal values of NEC and TC; neoplasias, diseases of the kidney and prostatic adenoma with residual urine had been excluded with reasonable certainty. There was no correlation between urinary cholesterol excretion and cholesterol plasma levels. In papilloma of the bladder (n = 16) NEC hyperexcretion was present in 56%; elevated levels of TC were determined in 68%. In carcinoma of the bladder, T1N0M0-T2N0M0 (n = 28), hyperexcretion of NEC occurred in 50% and of TC in 64%. In advanced clinical stages of the disease, T3N0M0-T4N4M1d (n = 21), elevated values of NEC were detected in 76% and of TC in 90%. Since all macroscopically blood contaminated urinary samples had been excluded, a determination of total urinary cholesterol excretion may be valuable in the diagnosis of papilloma or carcinoma of the bladder in the absence of macrohematuria. Occult blood in urine was present in 33 of the 65 patients with papilloma or carcinoma of the bladder, which was associated in 26 cases with elevated urinary total cholesterol. 32 patients revealed a negative test for occult blood in urine. In 22 of these, hyperexcretion of urinary total cholesterol was observed, indicating diagnostic sensitivity of this parameter for papilloma and carcinoma of the bladder even in the absence of microhematuria. However, one has to regard that elevated urinary cholesterol levels could also occur in other carcinomas of the urogenital system, prostatic adenoma with residual urine and kidney diseases.

Bei 35 Patienten mit endokriner Ophthalmopathie (eO) wurde zu den Parametern der Schilddrüsenfunktion (T3, T4, TBI, TRH-Test), dem Szintigramm und der Bestimmung der Schilddrüsenantikörper ergänzend die Ultrasonographie (A-scan) und Computertomographie (CT) der Orbita, sowie der Nachweis exophthalmogener Serumaktivität im Fischbioassay durchgeführt. Charakteristische Sonogramme für eine eO fanden sich in 26 Fällen. Die CT ergab bei 24 von 33 Patienten die Verdickung der musculi recti mediales und/oder der musculi recti laterales, sowie bei 17 Patienten eine Verdichtung im Bereich der Orbitaspitze. Im retrobulbären Bindegewebe zeigte sich nach Kontrastmittelgabe keine signifikante Dichtezunahme. Mit beiden Verfahren zusammen waren nur bei 2 Patienten die Kriterien einer eO nicht erfüllt. Die exophthalmogene Serumaktivität wurde in der IgG-Fraktion im Fischbioassay nachgewiesen; die Trefferquote war mit 69% relativ hoch. Zur Diagnostik der eO kann jedoch der Fischbioassay nicht empfohlen werden.

# 1.

Precipitating antibodies specific for apocytochrome c and holocytochrome c, respectively, were employed to study synthesis and intracellular transport of cytochrome c in Neurospora in vitro.

# 2.

Apocytochrome c as well as holocytochrome c were found to be synthesized in a cell-free homogenate. A precursor product relationship between the two components is suggested by kinetic experiments.

# 3.

Apocytochrome c synthesized in vitro was found in the post-ribosomal fraction and not in the mitochondrial fraction, whereas holocytochrome c synthesized in vitro was mainly detected in the mitochondrial fraction. A precursor product relationship between postribosomal apocytochrome c and mitochondrial holocytochrome c is indicated by the labelling data. In the microsomal fraction both apocytochrome c and holocytochrome c were found in low amounts. Their labelling kinetics do not suggest a precursor role of microsomal apocytochrome c or holocytochrome c.

# 4.

Formation of holocytochrome c from apocytochrome c was observed when postribosomal supernatant containing apocytochrome c synthesized in vitro was incubated with isolated mitochondria, but not when incubated in the absence of mitochondria. The cytochrome c formed under these conditions was detected in the mitochondria.

# 5.

Conversion of labelled apocytochrome c synthesized in vitro to holocytochrome c during incubation of a postribosomal supernatant with isolated mitochondria was inhibited when excess isolated apocytochrome c, but not when holocytochrome c was added.

# 6.

The data presented are interpreted to show that apocytochrome c is synthesized on cytoplasmic ribosomes and released into the supernatant. It is suggested that apocytochrome c migrates to the inner mitochondrial membrane, where the heme group is covalently linked to the apoprotein. The hypothesis is put forward that the concomitant change in conformation leads to trapping of holocytochrome c in the membrane. The probles of permeability of the outer mitochondrial membrane to apocytochrome c and the site and nature of the reaction by which the heme group is linked to the apoprotein are discussed.