Showing papers in "Acta vitaminologica et enzymologica in 1980"

Total and free tryptophan levels in serum of newborn infants. Relationships with the Serotonin and nicotinic acid pathways.

Abstract: The levels of total and free serum tryptophan have been determined in a group of newborn babies at birth, one day later and five days after birth. Total and free tryptophan levels are very high in the umbilical cord at birth, decrease quickly and significantly 24 hours after birth and show a slight, but not significant increase five days after birth. The high tryptophan levels at birth and their decrease in the first day after birth recall previous data on tryptophan metabolism "via" serotonin and "via" nicotinic acid. Since the synthesis of cerebral serotonin depends on the availability of tryptophan, and is thus linked to the level of free tryptophan in blood, these data suggest that synthesis of serotonin as well may be elevated at birth and may reach the values of adult soon afterwards. With respect to the nicotinic acid pathway the high levels of tryptophan in blood may be related to the synthesis of tryptophan pyrrolase, which is present in the liver of newborn babies.

Relationship between hemorrhagic ocular diseases and vitamin C deficiency: clinical and experimental data.

Abstract: The hematic level of ascorbic acid was significantly lower with respect to that of healthy subjects in 55 patients with hemorrhagic ocular diseases. Experiments on albino guinea pigs showed that an induced hypovitaminosis C (2 weeks of scorbutigenic diet followed by a maintenance dose of 0,5 mg of ascorbic acid) caused the appearance of widespread retina hemorrhages and a significant decrease of the blood ascorbate levels with respect to the control groups. The present results suggest that a prolonged insufficient dietary intake of ascorbic acid may give rise to hemorrhagic ocular pathologies in humans.

[Plasma levels of Zn, Cu and Ni in healthy controls and in psoriatic patients. Possible correlations with vitamins (author's transl)].

Abstract: Plasma levels of Zn, Cu and Ni were determined in psoriatic patients by atomic absorption spectrophotometry. In psoriatic patients, plasma Cu levels were significantly higher, whilst plasma Zn and Ni were significantly lower than in healthy controls.

Drugs producing vitamin deficiencies.

Abstract: Many drugs produce vitamin deficiencies. They belong to the most important and common therapeutical classes: analgesics, antianemics, antibacterial and antiblastic agents, antibiotics, antidiabetics, antimalarials, antiphlogistics, antipyretics, diuretics, laxatives and purgatives, tranquilizers and anticonvulsives, radiomimetics, hormones and vitamins themselves. The vitamin deprivation processes may be produced by a variety of mechanisms and may involve all vitamins. Recent experiments indicate that there is a competition for binding sites on proteins between vitamin C and salicylate and between dicoumarol and vitamin K. Usually a drug exerts a "devitaminizing" action with respect to only one vitamin. However there are examples of multiple vitamin deficiencies induced by a single drug, like salicylate which deprives the organism of vitamins C, K and pantothenate. These deficiencies may develop either all at the same time or successively. A direct and concomitant vitamin depriving action occurs when an antibiotic blocks the production of vitamins by the enteric flora. A different mode of action occurs in the drug induced folic acid deficiency, which in turn induces a deficiency of vitamin B12. It has been reported that a vitamin deficiency may result from intake of high pharmacological doses of other vitamins. These data need confirmation in patients treated with high doses of nicotinic acid. The drug induced vitamin deficiencies are studied with the same methodology employed for avitaminoses in general; hence they can be diagnosed using the same criteria.

The effect of thiamine on the contractile responses of the isolated heart muscle.

Abstract: Isolated papillary muscles of cats were exposed to increasing concentrations of thiamine during which the contractile response of myocardium to stimulation were measured. The results indicate that thiamine has no direct negative inotropic effect on the isolated heart muscle over a wide concentration range (0.1-1 mmol/l). Higher concentrations resulted in a concentration-related depression of all variables. The data indicate that thiamine in high doses as sometimes used in anesthesia (greater than 50 mg/kg) does not inhibit the contractile state of the myocardium. Blood pressure falls after massive doses of intravenous vitamin B1 are probably due to the synaptic blockade which is induced by the compound.

[Effect of vitamin B6 on some immune responses in chronic uremia (author's transl)].

Abstract: Patients with chronic uremia undergoing periodic haemodialysis were found to have low levels of vitamin B6 (12 out of 18 patients). The same subjects also showed a reduction of the immunocompetence. The AA. report that the administration of pyridoxine (100 mg/die for 4 weeks) can induce a normalization of the vitamin levels and of some immunological parameters.

Vitamins in "malattie evolutive".

Abstract: Vitamins are playing an increasingly important role in "malattie evolutive", both in the newer sense meaning diseases connected with general development and in the original sense of progressive diseases. Examples of the preventive use of vitamins in certain development phases are the prophylactic administration of vitamin E in premature and new-born babies as protection against retrolental fibroplasia, vitamin K against haemorrhage and vitamin D against bone deformation. Deficient ossification in osteogenesis imperfecta can be prevented by high doses of vitamin C. Recently, greater medical interest has centred around the preventive use of high vitamin dosage in "malattie evolutive" in the original sense. Here, the main interest has been in vitamins E and C which, as recent investigations show, are capable of retarding or preventing deleterious cardiovascular or oncological diseases.