Symptoms of 100 patients with electromyographically verified carpal tunnel syndrome

To determine the symptoms of carpal tunnel syndrome (CTS), screening evaluations were performed in 244 consecutive patients with sensory symptoms in the hand and unequivocal slowing of median nerve conduction at the wrist. This yielded 100 patients thought to have no explanation other than CTS for their upper limb complaints. These patients completed a hand symptom diagram (HSD) and questionnaire (HSQ) about their symptoms. CTS symptoms were most commonly reported in median and ulnar digits, followed by median digits only and a glove distribution. Unusual sensory patterns were reported by some patients. Based on the HSQ, paresthesias or pain proximal to the wrist occurred in 36.5% of hands. The usefulness of the HSD and HSQ for diagnosis was determined by asking three physicians, blinded to the diagnosis, to rate the likelihood of CTS in the patients with CTS and in 50 patients with other causes of upper extremity paresthesia. The sensitivities of the instruments ranged from 54.1% to 85.5%. Combining the HSD and HSQ ratings increased the range of sensitivities to 79.3% to 93.7%.

A vibrational model of the excitable membrane

A hypothesis is proposed which attributes the dynamic behaviour of the excitable biological membrane to postulated thermal vibrations of polar molecules in the membrane. It is suggested that these vibrations constitute the physical pumping mechanism for active transport and are also the seat of excitability. To illustrate the latter property the construction of a working mechanical model of coupled oscillators is described producing impulses which resemble the behaviour of the nerve impulse in all major aspects. A reinterpretation of this and some other prominent properties of the membrane is attempted in the light of the hypothesis.

A PROPOSED MECHANISM FOR THE EFFECT OF DIFFERENT DIETARY FATS ON SOME ASPECTS OF CHOLESTEROL METABOLISM

To explain the effect of dietary cholesterol and different fats on serum cholesterol concentration a hypothesis is proposed according to which the condition for the absorption of dietary cholesterol is its state of solution in dietary or endogenous fats. Dietary fats, free from cholesterol, exert their effect on serum cholesterol concentration by causing reabsorption of biliary or endogenous cholesterol. To test this hypothesis the solubility of cholesterol in a number of natural and modified triglyceride fats at 37 °C was determined and found to correlate with the effects of these fats on the serum cholesterol concentration of rats and man. Relatively high solubilities were associated with high serum levels and vice versa. Artificial modification of both unsaponifiable matter and fatty acids of triglyceride oils was found to alter the solubility of cholesterol in these oils. The solubility concept is discussed as a possible mechanism underlying the effect of different dietary fats on serum cholesterol concentration and other aspects of cholesterol metabolism such as absorption, excretion, and liver synthesis.

THE EFFECT OF DIETARY LIPIDS ON THE SERUM CHOLESTEROL OF RATS

Experimental conditions were devised under which the effect of dietary triglyceride oils on the serum cholesterol concentration of rats resembled the effect of these oils on man. No artificial additives were used in the diet. By the use of this technique, the hypocholesterolemic activity of sunflower seed oil was studied. The feeding of fractions prepared by chemical and physical means showed that the unsaponifiable matter was responsible for a substantial part of the hypocholesterolemic action of the unmodified oil. Several fractions with similar fatty acid compositions were prepared which had different effects on the serum cholesterol level. Some known compounds of the unsaponifiable matter were next fed, dissolved in coconut oil. β-Sitosterol and squalene had little effect but a combination of these with α-tocopherol and β-carotene produced a significant depressing effect. The administration of cholesterol with a fat-free diet did not raise the serum cholesterol level unless the sterol was given dissolved in oil. Increasing quantities of sterol of up to 6%, dissolved in oil, produced increasing serum levels. Larger quantities caused no further rise. The possibility that only dissolved cholesterol is absorbed is discussed.

A PROPOSED MECHANISM FOR THE EFFECT OF DIFFERENT DIETARY FATS ON SOME ASPECTS OF CHOLESTEROL METABOLISM

To explain the effect of dietary cholesterol and different fats on serum cholesterol concentration a hypothesis is proposed according to which the condition for the absorption of dietary cholesterol is its state of solution in dietary or endogenous fats. Dietary fats, free from cholesterol, exert their effect on serum cholesterol concentration by causing reabsorption of biliary or endogenous cholesterol. To test this hypothesis the solubility of cholesterol in a number of natural and modified triglyceride fats at 37 °C was determined and found to correlate with the effects of these fats on the serum cholesterol concentration of rats and man. Relatively high solubilities were associated with high serum levels and vice versa. Artificial modification of both unsaponifiable matter and fatty acids of triglyceride oils was found to alter the solubility of cholesterol in these oils. The solubility concept is discussed as a possible mechanism underlying the effect of different dietary fats on serum cholesterol concentration and other aspects of cholesterol metabolism such as absorption, excretion, and liver synthesis.