Study of hereditary fructose intolerance by use of 31P magnetic resonance spectroscopy

[Repeated perioperative administration of fructose and sorbitol in a female patient with hereditary fructose intolerance [HFI)]

The present paper reports on an adult female patient whose hereditary fructose intolerance (HFI) was at first not diagnosed and who, within the space of 2 years after repeated elective surgery and the perioperative administration of fructose and sorbitol, developed "hepatic and renal failure of unclear origin." At a later stage we were able to establish the diagnosis of HFI by means of a fructose tolerance test in both she and her brother, for whom intolerance to fruit and desserts had been known since early childhood. In addition, literature references to fatalities following the parenteral application of fructose and sorbitol were analyzed. During the course of fructose infusion in both the patient and her brother with HFI, the following metabolic changes were noted: hypoglycemia, elevated rise in the blood fructose concentration, hyperlactacidemia, elevated rise in the blood fructose concentration, hyperlactacidemia, and hyperammonemia. These metabolic changes proved to be reversible after discontinuing the fructose infusion. Analysis of the literature on the fatalities following parenteral fructose administration established that fruit and dessert intolerance was known for all collated patients with HFI, and that, clearly, no regular metabolic tests had been conducted.

31P magnetic resonance spectroscopy detects a functional abnormality in liver metabolism after acetaminophen poisoning

Eighteen patients with acetaminophen poisoning were studied with 31P magnetic resonance spectroscopy to measure phosphorus-containing metabolites in their livers. The concentrations of all magnetic resonance-detectable metabolites fell in parallel with a decrease in the synthetic ability of the liver, indicated by the prothrombin time ratio (international normalized ratio). In particular, ATP fell to about 20% of its normal concentration in severely affected patients, as did the phosphodiester signal, which is thought to arise mainly from the endoplasmic reticulum in the liver. The correlation between ATP levels and international normalized ratio suggests that the international normalized ratio is a more accurate measure of the number of viable hepatocytes than are other biochemical tests.

Serial P-31 MR spectroscopy after fructose infusion in patients with chronic hepatitis

Serial changes in phosphorus metabolites after intravenous administration of fructose were compared between five healthy volunteers and five patients with chronic hepatitis by means of phosphorus-31 magnetic resonance (MR) spectroscopy. P-31 spectra were obtained every 5 minutes after intravenous drip infusion of 20% fructose at a dose of 0.5 g/kg of body weight. In the healthy volunteers, phosphomonoesters (PME) increased to 338% +/- 76% of the preadministration value at 15-20 minutes. Inorganic phosphate (Pi) was depleted in the first 15 minutes, then rebounded to 260% +/- 67% of the initial value. beta-adenosine triphosphate decreased to less than 50% of its initial value and then gradually recovered. In patients with chronic hepatitis, the increase of PME at 15-20 minutes (151% +/- 49% of the preadministration value) was significantly less than that in healthy volunteers (P less than .05). In addition, the rebound of Pi at 35-40 minutes (126% +/- 42%) was significantly less than that in healthy volunteers (P less than .05). In conclusion, P-31 MR spectroscopy with fructose administration is valuable in the functional evaluation of diffuse liver diseases.

Hepatic intracellular pH in vivo using F-quene 1 and 19F NMR spectroscopy

Intracellular pH (pHi) has been determined in vivo in livers from anaesthetized rats using both 31P NMR and 19F NMR spectroscopy. In the 31P NMR study pHi, determined from the chemical shift of endogenous Pi, was found to be 7.26 +/- 0.02. In the 19F NMR study on a separate group of animals pHi was determined from the chemical shift of F-Quene 1 infused via the portal vein and found to be 7.18 +/- 0.01. In approximately half of the 19F NMR studies no 19F signal could be detected in the liver probably because of the two probes could be caused by different intra- or intercellular distributions or by unknown effects of F-Quene 1 on metabolism.

Fructose-induced aberration of metabolism in familial gout identified by 31P magnetic resonance spectroscopy

The hyperuricemia responsible for the development of gouty arthritis results from a wide range of environmental factors and underlying genetically determined aberrations of metabolism. 31P magnetic resonance spectroscopy studies of children with hereditary fructose intolerance revealed a readily detectable rise in phosphomonoesters with a marked fall in inorganic phosphate in their liver in vivo and a rise in serum urate in response to very low doses of oral fructose. Parents and some family members heterozygous for this enzyme deficiency showed a similar pattern when given a substantially larger dose of fructose. Three of the nine heterozygotes thus identified also had clinical gout, suggesting the possibility of this defect being a fairly common cause of gout. In the present study this same noninvasive technology was used to identify the same spectral pattern in 2 of the 11 families studied with hereditary gout. In one family, the index patient's three brothers and his mother all showed the fructose-induced abnormality of metabolism, in agreement with the maternal inheritance of the gout in this family group. The test dose of fructose used produced a significantly larger increment in the concentration of serum urate in the patients showing the changes in 31P magnetic resonance spectra than in the other patients with familial gout or in nonaffected members, thus suggesting a simpler method for initial screening for the defect.

Study of human liver disease with P-31 magnetic resonance spectroscopy

Liver metabolism and energetics of 24 patients with liver disease were studied using phosphorus-31 magnetic resonance spectroscopy. Significant abnormalities were detected in the majority of these patients. A striking diversity in metabolic patterns was observed. Patients with acute viral hepatitis had low liver phosphodiesters and high phosphomonoesters, possibly phosphocholine and phosphoethanolamine. In alcoholic hepatitis phosphomonoesters were raised. Intracellular inorganic phosphate and inorganic phosphate/ATP ratios were decreased in primary biliary cirrhosis and in some patients with hepatitis. These spectroscopic results were evaluated in respect of the pattern of liver damage and cellular regeneration. Liver tumours had raised phosphomonoesters and also showed evidence for altered spin-lattice relaxation of the phosphorus nucleus in various metabolites. In iron overload the liver ATP resonances were broadened. The line broadening correlated with the degree of iron overload suggesting the potential use of P-31 magnetic resonance spectroscopy for measuring liver iron.

Hereditary fructose intolerance

Hereditary fructose intolerance (HFI) is an inborn error of carbohydrate metabolism that is inherited as an autosomal recessive condition. The disease is caused by a catalytic deficiency of aldolase B and is characterized by severe abdominal symptoms and hypoglycaemia which follow the ingestion of fructose, sucrose or sorbitol. The exact prevalence of HFI in different populations is unknown but studies from Switzerland suggest a disease frequency of about 1 in 20,000 live births, thus predicting a carrier frequency of greater than 1% and a gene prevalence that approaches polymorphic frequency. It is notable that many patients who endure severe symptoms during early infancy develop a marked aversion to harmful foodstuffs and thereby survive to adulthood. Although exposure to fructose may prove to be fatal in this disorder, institution of a strict exclusion diet is curative. HFI, when treated rigorously after diagnosis, is thus compatible with a long and healthy life. HFI vividly illustrates the interplay of dietary factors and heredity in the development of human disease. The recent identification of genetic lesions that cause this disorder further demonstrates the remarkable clinical benefits that may accrue from the study of the molecular basis of inherited diseases and its population genetics: it is now possible to detect asymptomatic disease carriers and diagnose the disorder in affected families by non-invasive analysis of small samples of genomic DNA. Moreover, the systematic investigation of natural mutations in the human gene for aldolase B has allowed regions that are critical for catalytic function of this enzyme to be identified as part of an extended study of its molecular biology.

Molecular analysis of aldolase B genes in hereditary fructose intolerance

The molecular basis of hereditary fructose intolerance (HFI) was studied in 50 subjects (41 pedigrees, 82 apparently independent mutant alleles of aldolase B) by direct analysis of aldolase B genes amplified by means of the polymerase chain reaction. The mutation A149P (ala 149----pro) was found in 67% of alleles but was significantly more common in patients from northern than from southern Europe. Two other point mutations of aldolase B were identified. A174D (C----A; ala 174----asp) was found in subjects from Italy, Switzerland, and Yugoslavia (overall frequency 16%) but not in those from the United Kingdom, France, or the United States. L288 delta C carried a single base-pair deletion causing frameshift at codon 288 and was restricted to Sicilian subjects. By testing for these mutations in amplified DNA with a limited panel of allele-specific oligonucleotides, more than 95% of HFI patients will be susceptible to genetic diagnosis.

Nuclear magnetic resonance in clinical pharmacology and measurement of therapeutic response

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