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Biomedical subjects

D M Danks

Publications and source records attributed to D M Danks.

At least 199 records · Page 11Linked to original sources
PubMed1977

A new sulfur amino acid, named hawkinsin, identified in a baby with transient tyrosinemia and her mother.

An unknown compound present in the urine of a girl with prolonged transient tyrosinemia and her mother was isolated and identified as (2-L-cystein-S-yl-1,4-dihydroxycyclohex-5-en-1-yl)-acetic acid (IVa). The new amino acid was named hawkinsin (Haw) and characterized by gas chromatography-mass spectrometry (GC-MS) of its penta-trimethylsilyl (TMS) derivative and of its desulfuration components. Haw was compared with the synthetic reference compound using GC-MS, IR, TLC, PC, ion-exchange chromatogrpahy and high-voltage electrophoresis. IVa and (2,6-bis-L-cystein-S-yl-1,4-dihydroxycyclohexyl-1)-acetic acid were synthesized from 4-quinolacetic acid, the latter was prepared in two different ways. It is postulated that Haw originates from an intermediate in the 4-hydroxy-phenylpuruvate hydroxylase reaction (EC 1.14.2.2), and that mother and child are heterozygous for an inborn error of metabolism characterized by a defect in this hydroxylase system, which is unable to rearrange the intermediate to homogentisic acid.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1977

Iminopeptiduria, skin ulcerations, and edema in a boy with prolidase deficiency.

A 12-year-old boy with recurrent skin ulceration, chronic generalized lymphedema, and mild mental retardation was found to excrete massive amounts of dipeptides, most (but not all) of which had proline or hydroxyproline as the carboxyl terminal residue. Glycylproline predominated. Prolidase deficiency was demonstrated in red blood cells and in fibroblastic cells. Prolidase activity was present in continuous lymphoid cell cultures at the same low level observed in control cells.

Amino Acids↗
PubMed1977

Asphyxiating thoracic dysplasia. Clinical, radiological, and pathological information on 10 patients.

Review of 10 cases of asphyxiating thoracic dysplasia has shown a wide range of clinical effects and some variability in the radiographic features. Respiratory difficulty was severe in 7 babies and lethal in 6 of these. The seventh child is remarkable for his normal stature and excellent health at 15 years of age. 3 babies had no respiratory difficulty but 2 of them subsequently died of renal failure; one remains alive at 3 years. Microscopical abnormalities in the liver and kidneys were very frequent and appeared to increase progressively with age.

Adolescent↗
PubMed1977

Studies of the aetiology of neonatal hepatitis and biliary atresia.

Aetiological factors were sought prospectively in 55 babies with extrahepatic biliary atresia, in 105 with neonatal hepatitis, and in 11 with intrahepatic biliary atresia, seen as a result of nearly complete ascertainment of these conditions in the State of Victoria between 1963 and 1974. In neonatal hepatitis infective causes were shown in 22 babies, galactosaemia in 6 and alpha1-antitrypsin deficiency in 8; familial occurrence was noted in 10 further babies and unrelated second diseases were present in 24 of the remaining 59 babies. The only clues to aetiology in extrahepatic biliary atresia were a suspicion of time-space clusters, a deficiency of affected babies born to young primiparous women, and an unexpected number of spontaneous abortions in the histories given by the mothers. Genetic factors appeared to be important in intrahepatic biliary atresia, but are not reported in detail. Hypotheses for the aetiology of neonatal hepatitis and of extrahepatic biliary atresia are presented. Both are considered syndromes with multiple causes. Recurrence risks in sibs are discussed, and are 1 in 7 for neonatal hepatitis of unknown cause, negligible in extrahepatic biliary atresia, and usually 1 in 2 or 1 in 4 in intrahepatic biliary atresia, depending upon the family history.

Abortion, Spontaneous↗
PubMed1977

Prognosis of babies with neonatal hepatitis.

105 babies with neonatal hepatitis were studied carefully and followed for up to 11 1/2 years. Ascertainment was complete for those with severe and persistent jaundice, but less complete for mild or anicteric cases. Prognosis was found to be poor (40% death or cirrhosis) in babies with perisitently acholic stools, but relatively good (less than 15% death or cirrhosis) in those with jaundice which was less persistent and less obstructive. The presence of second diseases (including alpha1-antitrypsin deficiency or a family history of other affected children) seemed to play a part in determining poor prognosis. A distinctive group of babies (22 cases) presented with acute fulminant illness (with or without jaundice) in the neonatal period. Cytomegalovirus infection carried a relatively good prognosis. Guidelines for selection of patients for therapeutic trials are suggested.

Child↗
PubMed1977

Metabolic studies on two patients with nonhepatic tyrosinemia using deuterated tyrosine loads.

Metabolic studies on two patients with defects in the tyrosine oxidation pathway are reported. Serum tyrosine was greatly elevated in both patients (1.37 and 1.52 mmol/liter, respectively) and both excreted large quantities of p-hydroxyphenylacetic acid, p-hydroxyphenyllactic acid, and p-hydroxyphenylpyruvic acid. Deuterated tyrosine loads were administered to both patients, before and after lowering of the serum tyrosine concentration by dietary treatment, and to a normal adult control subject. In one patient the excretion of the deuterated (D2)-tyrosine load was more than 300 times that found in the control subject whether the test was done at high or low serum tyrosine level and the pattern of metabolites indicated a persistent defect in p-hydroxyphenylpyruvic acid oxidase. Enzyme assays on needle liver biopsy supported this finding. In the second patient excretion of the D2 label was 300 times that of the control at high serum tyrosine levels, but only 5 times normal at low serum tyrosine levels. This finding was interpreted as indicating substrate inhibition of p-hydroxyphenylpyruvic acid oxidase. The primary defect has not been established in this patient, but the findings are compatible with a defect in hepatic-soluble tyrosine aminotransferase.

4-Hydroxyphenylpyruvate Dioxygenase↗
PubMed1976

Dihydrofolate reductase deficiency causing megaloblastic anemia in two families.

To determine the cause of severe megaloblastosis detected at birth and at four weeks in two unrelated infants their bone marrow and liver cells were studied. Both patients had abnormal deoxyuridine suppression tests, corrected to normal by 5-formyl tetrahydrofolic acid. Liver-cell homogenate from one patient had a previously undetectable level of dihydrofolate reductase restored to normal by high cation concentration in the assay. Activity of the liver-cell homogenate from the other patient, which was one quarter of the normal level, was restored to only half normal activity by high cation concentration. Dihydrofolic acid reductase deficiency prevents this conversion of folic acid to tetrahydrofolic acid; the enzyme activity appears to differ in each patient. A satisfactory clinical response in both patients followed parenteral therapy with 5-formyl tetrahydrofolic acid. One sibling in each family died of a similar illness. Autosomal recessive inheritance is probable.

Anemia, Macrocytic↗