Further evidence of genetic heterogeneity in hereditary hydronephrosis

Hereditary hydronephrosis is a rare condition but several families are described in the literature. The inheritance pattern is autosomal dominant (McKusick number 143400) but the exact aetiology of the hydronephrosis is not clear. However, linkage with the HLA region on chromosome six has been shown previously. We report a family not showing linkage to this region, giving further evidence of genetic heterogeneity in this condition.

Persistent movement disorders induced by buspirone

Buspirone, an azospirone compound, is a nonsedative anxiolytic that has achieved wide usage since its introduction in 1987. Although relatively free of side-effects, there have been several instances of dyskinesia and dystonia associated with the use of buspirone. We report two patients with persistent movement disorders that developed after prolonged treatment with the drug. One patient developed a lasting problem of cervical-cranial dystonia and tremors after treatment with buspirone at a dosage of 40 mg/day for several weeks. Another, receiving 30 mg/day for 6 weeks, experienced an exacerbation of preexisting spasmodic torticollis and tardive dyskinesia as well as the onset of involuntary phonations. As shown by these and other examples, buspirone poses the risk for inducing or exacerbating several types of movement disorders.

A blinded study of the suppressibility of involuntary movements in Huntington's chorea, tardive dyskinesia, and L-dopa-induced chorea

Videotapes of patients with Huntington's chorea, tardive dyskinesia (TD), and L-DOPA-induced chorea in Parkinson's disease were taken while the patients were seated with their legs dangling. The videotapes were scored in a blinded fashion for suppressibility of dyskinesias. Most patients with TD or L-DOPA-induced chorea substantially suppressed their involuntary movements, whereas most patients with Huntington's chorea did not. There was a small overlap between the TD and Huntington's chorea groups and suppressibility therefore could not absolutely distinguish between them. Suppressibility testing may nonetheless be a valuable clinical tool since a good, excellent, or complete suppressibility rating was highly suggestive of TD but not Huntington's chorea. TD and L-DOPA-induced chorea may be more pathophysiologically similar to each other than either is to Huntington's chorea.

The presence of free D-aspartic acid in rodents and man

Free D-aspartic acid is present in appreciable quantities in the brain and other tissues of rodents and in human blood. In the newborn rat, the highest concentration of D-aspartic acid was found in cerebral hemispheres, where, at 164 nmol/g (8.4% of the total aspartic acid), the level of D-aspartic acid exceeds that of many essential L-amino acids. The highest ratio of D- to total aspartic acid (38%) occurred in neonatal blood cells. In the adult rat, the highest concentration was present in the pituitary gland (127 nmol/g, 3.8%). Within the central nervous system marked regional differences are present and characteristic changes with development take place. In general, the levels of D-aspartic acid fall rapidly with increasing age. In cerebral hemispheres adult values (13 nmol/g, 0.43%) are approached within one week. D-aspartic acid concentrations may also be higher in young humans since fetal blood, taken from placental cord, contains 2.6 nmol/g (4.9%) of D-aspartic acid, a value five times that of adult human blood. These distributional patterns and developmental changes may be the result of differences in the ability of various tissues to dispose of an extraneous metabolite, or, reflect alterations in a specific functional requirement for D-aspartic acid.

Vitamin E and stress. 4. The metabolism of D-alpha-tocopherol during nutritional hepatic necrosis in the rat and the effects of selenium, methionine and unsaturated fatty acids

1. Liver necrosis was produced in rats given diets deficient in selenium and vitamin E and the metabolism of [5-Me-14C]D-α-tocopherol was studied during the development of the disease. 2. When a torula yeast diet (containing sufficient of the yeast to provide essential fatty acids) was used, the addition of 5 % cod-liver oil fatty acid methyl esters produced only a slight decrease in the time taken to produce the disease, compared to controls given methyl oleate; methionine had little protective effect. The metabolism of the radioactive tocopherol was unaffected by dietary lipid, Se or methionine and was not influenced by the development of necrosis. 3. When a casein diet (devoid of fat and containing insufficient Se to prevent liver necrosis) was used, the addition of small amounts of linoleic acid to the diet (as 2 % maize oil fatty acid methyl esters) decreased the time taken to produce the disease and increased its incidence. However, the metabolism of the radioactive tocopherol was independent of dietary lipid or Se. 4. It would appear that either Se or vitamin E may be necessary for effective utilization of the ratapos;s requirement for linoleic acid.

Vitamin E and stress. I. Dietary unsaturated fatty acid stress and the metabolism of alpha-tocopherol in the rat

1. A critical analysis of the biological antioxidant theory of vitamin E function has been made and the implications of the theory have been tested.

2. When small amounts of [5-Me-14C]α-tocopherol were present in lipid systems subject to autoxidation in vitro, it was found that, whether the tocopherol was the sole antioxidant or was in synergistic combination with a secondary antioxidant (ascorbic acid), peroxidation did not occur without concomitant destruction of the tocopherol. This was so, whether a simple fat substrate or a liver homogenate (subject to catalysis) was used. The decomposition of tocopherol took place even when the secondary antioxidant was in large excess, as would occur under physiological conditions in the vitamin E-deficient animal, and accelerated as the induction period neared its end.

3. When [5-Me-14C,3H]α-tocopherol and ascorbic acid were used as a synergistic antioxidant couple in vitro, tocopherol recovered from the peroxidizing system always had the same isotopic ratio as the starting material. This means that regeneration of tocopherol by the secondary antioxidant cannot involve, as an intermediate, a tocopherol carbon radical formed by loss of hydrogen from the 5-methyl group. Such radicals probably dimerize before they can be regenerated. The same result was found when doubly labelled α-tocopherol was given to the rat and recovered later from its tissues.

4. In a series of experiments, rats were rigorously depleted of vitamin E for periods up to 7 months and then given as little as 50 μg [14C]D-α-tocopherol. They were then given, either by stomach tube daily or by dietary addition, large amounts of methyl linoleate or vitamin E-free polyunsaturated fatty acid methyl esters prepared from cod-liver oil and compared with controls given methyl oleate for up to 31 days. When the possibility of interaction between the lipid and tocopherol in the gut was eliminated, analyses of liver, kidney, testis, adrenal, adipose tissue, whole carcass and faeces showed that there was no effect of the polyunsaturated fatty acids on either the metabolism or recovery of [14C]α-tocopherol in any of the animals.

5. When interaction between the administered fatty acid esters and tocopherol in the gut was allowed to take place, a marked destruction of [14C]α-tocopherol in the tissues was observed in animals given the polyunsaturated esters. The importance of oxidative destruction of tocopherol in the gut before absorption was demonstrated in a nutritional trial, in which cod-liver oil and lard were compared and the degrees of resistance of rats' erythrocytes to dialuric acid-induced haemolysis was used as an index of vitamin E depletion.

6. Similar experiments with [14Cα-tocopherol in weanling rats given large amounts of cod-liver oil methyl esters also showed little effect. Although there was a suggestion that prolonged feeding of partly peroxidized polyunsaturated esters could lead to a slight depression of tissue tocopherol concentrations, no significant differences were usually obtained.

7. Fourteen-day-old rats were given a vitamin E-deficient diet and received three weekly doses of 0.5 mg α-tocophcryl acetate. The dosage was stopped, the rats were then given a deficient diet containing 4% of either vitamin E-free linseed oil fatty acids or oleic acid, and the rate of their tocopherol depletion was measured by the erythrocyte haemolysis test. No effect of the polyunsaturated fatty acids was found. Nor was there any effect on the concentrations of ‘secondary antioxidants’ (glutathione and ascorbic acid) in liver, kidney, testis, muscle or adipose tissue.

8. The results of the experiments in vivo contrast strongly with those in vitro. They lead to the conclusion that lipid peroxidation, if it occurs in the living animal, is irrelevant to the problem of vitamin E function. This conclusion has been substantiated by a critical review of the literature on the quantitative aspects of the vitamin E-dietary fat relationship.

9. The effects of dietary fat stress in vitamin E-deficient animals are, we believe, due to two causes: (1) destruction of tocopherol in the diet or in the gastro-intestinal tract of the animal, and (2) the existence of an increased requirement for vitamin E for the metabolism of certain long-chain fatty acids. The specific effects of certain of these substances in producing or accelerating some vitamin E deficiency diseases may be related to the toxic states known to be induced in vitamin E-deficient animals by other stress factors.

Vitamin E and stress. 3. The metabolism of D-alpha-tocopherol in the rat under dietary stress with silver

1. When weanling rats were given a vitamin E-deficient diet and 0.15% (w/v) silver acetate in their drinking water, there was a high incidence of liver necrosis and death after 2–4 weeks. This was prevented by 120 ppm D-α-tocopheryl acetate in the diet, was partially prevented by selenium at 1 ppm but not at 0.05 ppm and was only marginally prevented by 0.15% DL-methionhe.

2. All these effects were observed when the diet was free of fat and when it contained either methyl oleate or polyunsaturated methyl esters. The polyunsaturated lipid slightly increased the velocity of the terminal illness.

3. In spite of the ‘anti-vitamin E’ effect of Ag and the clear demonstration that α-tocopherol played a major part in preventing toxicity, experiments with tracer amounts of [5-Me-14C]-D-α-tocopherol showed that rather than there being any destruction of tocopherol in the critical period preceding the onset of disease, there was an increase in tocopherol in the liver due to Ag administation. The metabolism of tocopherol in the remainder of the animal was unaffected during the pre-necrotic phase.

4. The results are inconsistent with the view that the stress induced by Ag is caused by a pro-oxidant effect, either in the gastro-intestinal tract or in the tissues of the rat. They show that lipid peroxidation is not a causal factor in the aetiology of Ag-induced liver necrosis and suggest that stress in the vitamin E-deficient animal probably raises the requirement for tocopherol.

Vitamin E and stress. II. The metabolism of D-alpha-tocopherol and the effects of stress in vitamin E deficiency in the chick

1. The metabolism of small amounts of [5-Me-14C]D-α-tocopherol and [5-Me-3H]D-α- tocopherol has been studied in the vitamin E-deficient chick. Small doses of the labelled tocopherol were given to chicks, which were then subjected to stress by giving them diets formulated to produce encephalomalacia, exudative diathesis or muscular dystrophy.

2. Tocopherol concentrations in the cerebella and brains of chicks with incipient encephalomacia were the same as those in normal chicks in which the dietary fat stress was absent.

3. α-Tocopherol delayed the onset of encephalomalacia by a mean value of 3.5 days when its concentration in the cerebellum was about 2 × 10−7g/g of lipid. This concentration is considerably below the usual effective concentrations of antioxidants in vitro.

4. Selenium deficiency, under conditions leading to a high incidence of exudative diathesis, was not associated with lowered tocopherol levels and did not result in detectable destruction of tocopherol.

5. Nor was there any destruction of tocopherol or significant effect on its metabolism in the processes leading to muscular dystrophy: on the contrary, the affected muscles of dystrophic chicks, which had received a diet deficient in sulphur amino acids, contained significantly more tocopherol than muscles from control birds.

6. These results do not support the hypothesis that lipid peroxidation is a causative process in the aetiology of vitamin E-deficiency diseases in the chick. The relationships between unsaturated lipid, Se, sulphur amino acids and tocopherol in the chick require further exploration.

Vitamin K and oxidative phosphorylation

1. Oxidative phosphorylation was studied in a cell-free preparation of Mycobacterium phlei and in rat-liver mitochondria. Phosphorylation was destroyed in both systems by long-wave ultraviolet radiation and restored by the addition of small amounts of [2-Me-(14)C,(3)H]phylloquinone. When the radioactive quinones were recovered from the phosphorylating system and chromatographed with carrier phylloquinone and menaquinone-4 in adsorption and partition systems, only the phylloquinone band was labelled, and its isotopic ratio was identical with that of the original [2-Me-(14)C,(3)H]phylloquinone. This result does not support the contention that the role of vitamin K in oxidative phosphorylation involves a cyclic mechanism with intermediate formation of a quinone methide. 2. When the [2-Me-(14)C,(3)H]phylloquinone was given intravenously to rats and radioactive phylloquinone isolated from their liver mitochondria and microsomes 20hr. later, its isotopic ratio was unchanged. There was thus no evidence for quinone methide formation in vivo. No measurable conversion of phylloquinone into menaquinone-4 was observed. 3. When [(14)C]menadione was given intraperitoneally to rats whose alimentary tract had been treated with neomycin, conversion into menaquinone-4 was found in the liver mitochondria and microsomes, but there was also some indication that there had been synthesis of phylloquinone.

The analysis of alpha-tocopherol and ubiquinone in rat liver

1. A comparative study has been made of five methods of saponifying normal and vitamin E-deficient rat liver and subsequently measuring ubiquinone and α-tocopherol. 2. Losses of ubiquinone and α-tocopherol occur under certain conditions, and three of the methods were judged to be unsatisfactory. Recoveries of α-tocopherol are nearly quantitative under the conditions of ToŠić & Moore (1945), but methods that use large reaction times or weaker alkali destroy tocopherol, and over 50 % loss can be encountered. Ubiquinone does not seem as sensitive to the time of reaction, but is sensitive to the concentration of alkali and amount of water present during saponification.