A faster radioimmunoassay of progesterone in plasma, with use of polyethylene glycol as precipitant.

We report a reliable radioimmunoassay for plasma progesterone in which polyethylene glycol ("Carbowax 6000") is used to separate antibody-bound and free hormone. Initially, progesterone is concentrated by putting the sample through a column of LH-20 Sephadex. Procedural losses in each sample are not monitored.

Discharge pattern of single motor units in the tonic vibration reflex of human triceps surae.

Using a single fibre EMG electrode the firing pattern of 46 motor units in the triceps surae has been studied during vibration of the Achilles tendon at frequencies of 25--200 Hz. Potentials activated in the tonic vibration reflex (TVR) were phase-locked to the vibration cycle but tended to become somewhat less so with continued vibration. The firing pattern of voluntarily activated motor units became locked to the waveform by the application of the vibrator.

A rapid specific radioimmunoassay for unconjugated estriol in plasma.

A rapid, non-chromatographic radioimmunossaay for unconjugated estriol in pregnancy plasma has been developed which utilizes a commonly available antiestrogen antisera. Estradiol-17beta and estrone demonstrate 135% relative cross-reactivity with our antiserum, as compared with 100% for estriol. Specificity is achieved by purification of estriol with solvent partitioning using benzene: petroleum ether (1:1).

The normal motor unit in man. A single fibre EMG multielectrode investigation.

The motor unit in the normal EDC and biceps brachii muscle was studied with a multielectrode technique permitting recording from 44 sites 300 mum apart. It was found that the muscle fibres in man are scattered with no evidence of grouping, similar to the findings in glycogen depletion experiments in animals.

Nonchromatographic radioimmunoassay of unconjugated estriol in plasma, with polyethylene glycol as precipitant.

We describe a rapid, reliable radioimmunoassay for unconjugated estriol in plasma. Polyethylene glycol (Carbowax 6000) is used to separate antibody-bound and free steroid. The assay is sensitive (25 pg for standards), precise, and accurate.

The reinnervated motor unit in man. A single fibre EMG multielectrode investigation.

Motor units in patients with motor neurone disease and polyneuropathy were studied with a new multielectrode technique allowing fibre mapping. In these disorders which are characterised by reinnervation the motor unit fibre distribution is changed from a normal scattered pattern to grouping often in clinically uninvolved muscles without definite EMG abnormalities. The changes found with this multielectrode technique in man are in accordance with those found in reinnervated motor units studied histochemically in the experimental animal.

Regional curare for the reduction of the safety factor in human motor end-plates studied with single fibre electromyography.

A method employing six minutes of regional curarization with 0.5 mg D-tubocurarine and single fibre electromyographic measurements (SFEMG) was used in order to study the effect of an additional small dose of D-tubocurarine. The effect of the additional dose was most pronounced in terms of increased jitter, on motor end-plates with the initially highest jitter.

Safety factor in single human motor end-plates studied in vivo with single fibre electromyography.

In a single fibre EMG investigation on healthy subjects the relationship between the neuromuscular jitter and the safety factor of the motor end-plate relative to curare was studied. A positive correlation was found between the jitter increase after a standard dose of D-tubocurarine and the initial jitter. The conclusion was drawn that the neuromuscular jitter can be used as an indicator of the safety factor.

Nonchromatographic radioimmunoassay of plasma 11-deoxycortisol, for use in the metyrapone test, with polyethylene glycol as the precipant.

We have developed a simple, reliable radioimmunoassay for plasma 11-deoxycortisol. The method does not require chromatography but instead makes use of a simple extraction procedure which, in combination with the antibody characteristics, is highly specific for the metyrapone test. Polyethylene glycol was used to separate free and antibody-bound steroid.

Radioimmunoassay of plasma testosterone, with use of polyethylene glycol to separate antibody-bound and free hormone.

We have developed a reliable radioimmunoassay for testosterone in plasma, polyethylene glycol ("Carbowax 6000") being used to separate antibody-bound and free hormone. Testosteron is separated from interfering steroids, notably dihydrotestosterone, by liquid-liquid partition chromatography on infusorial earth (Celite). The assay is sensitive (9 pg for standards), precise, and accurate.

Perturbations of the human menstrual cycle by oxymetholone.

The luteolytic activity of oxymetholone, and anabolic steroid, has been evaluated in 10 women. Administration early in the follicular phase of the cycle inhibited ovulation and prolonged the duration of the cycles in 2 of 3 subjects, but treatment beginning on Day 10 (3 subjects) did not prevent ovulation, although subsequent plasma progesterone concentrations were reduced. Treatment after ovulation (4 subjects) suppressed progesterone levels by 50 to 80 per cent and shortened cycle length by 6 to 8 days.