Drugs and acute porphyrias: reasons for a hazardous relationship.

The porphyrias are a group of metabolic diseases caused by inherited or acquired enzymatic deficiency in the metabolic pathway of heme biosynthesis. Simplistically, they can be considered as storage diseases, because the partial enzymatic defect gives rise to a metabolic "bottleneck" in the biosynthetic pathway and hence to an accumulation of different metabolic intermediates, potentially toxic and responsible for the various (cutaneous or neurovisceral) clinical manifestations observed in these diseases. In the acute porphyrias (acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, and the very rare delta-aminolevulinic acid dehydratase ALAD-d porphyria), the characteristic severe neurovisceral involvement is mainly ascribed to a tissue accumulation of delta-aminolevulinic acid, a neurotoxic nonporphyrin precursor.

A challenging diagnosis for potential fatal diseases: recommendations for diagnosing acute porphyrias.

Acute porphyrias are a heterogeneous group of metabolic disorders resulting from a variable catalytic defect of four enzymes out of the eight involved in the haem biosynthesis pathway; they are rare and mostly inherited diseases, but in some circumstances, the metabolic disturbance may be acquired. Many different environmental factors or pathological conditions (such as drugs, calorie restriction, hormones, infections, or alcohol abuse) often play a key role in triggering the clinical exacerbation (acute porphyric attack) of these diseases that may often mimic many other more common acute medical and neuropsychiatric conditions and whose delayed diagnosis and treatment may be fatal. In order to obtain an accurate diagnosis of acute porphyria, the knowledge and the use of appropriate diagnostic tools are mandatory, even in order to provide as soon as possible the more effective treatment and to prevent the use of potentially unsafe drugs, which can severely precipitate these diseases, especially in the presence of life-threatening symptoms.

The acute porphyrias: a diagnostic and therapeutic challenge in internal and emergency medicine.

The porphyrias are a heterogeneous group of metabolic diseases resulting from a variable catalytic defect of one of the eight enzymes involved in the heme biosynthesis pathway; they are mostly inherited diseases, but in some circumstances the metabolic disturbance may be acquired. The specific patterns of tissue overproduction (and hence accumulation and excretion) of toxic heme precursors, associated with each enzymatic deficiency, are responsible for the characteristic biochemical and clinical features of each of these diseases. Moreover, even in the presence of a specific inherited enzymatic defect, many different environmental factors (such as drugs, calorie restriction, hormones, sunlight exposition, infections, etc.

A large deletion on chromosome 11 in acute intermittent porphyria.

Acute intermittent porphyria (AIP) is an autosomal disorder caused by molecular abnormalities in the gene coding for hydroxymethylbilane synthase (HMBS), the third enzyme in the heme biosynthetic pathway. So far, more than 242 different mutations responsible for AIP have been identified in this gene. In an Italian family with typical clinical and biochemical signs of AIP, no mutation was found by direct sequencing of the entire hydroxymethylbilane synthase gene (HMBS).

Retinol and tocopherol content in primary and metastatic digestive neoplasms.

Background: Recent trials in digestive-tract cancer have produced conflicting results regarding the protective role of liposoluble vitamins. Accordingly, we have undertaken an extensive appraisal of the behaviour of retinol and tocopherol in both human upper and lower digestive neoplasms.

Materials And Methods: The subjects comprised six healthy controls, 10 patients with symptomatic cholelithiasis, 13 with gastric neoplasms, 12 with colo-rectal neoplasms and 13 with digestive neoplasms and liver metastases.