Molecular diagnosis of maple syrup urine disease: screening and identification of gene mutations in the branched-chain alpha-ketoacid dehydrogenase multienzyme complex.
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Biomedical subjects
Publications and source records attributed to I Matsuda.
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Using a polymerase chain reaction method, a search for Y-specific DNA sequences was made in samples derived from tissues of a 46,XX true hermaphrodite. We found a sequence of SRY in the ovotestis, skin and leukocytes. Other DNA sequences, which covered the pseudoautosomal boundary region, amelogenin gene and DYZ1 locus of Y-chromosome were not detected. The SRY gene detected in the patient by the polymerase chain reaction was not detected by Southern blot analysis, using the SRY fragment as a probe. These findings suggest that in the patient there is a mosaicism of cells with and without part of the Y chromosome, including the SRY sequence. As the SRY sequence was responsible for the development of the gonadal primordium to the ovotestis, SRY seems essential for gonadal differentiation in testis development.
Activation of T cells is initiated by the recognition of antigen on antigen presenting cells to exert the effector functions in immune and inflammatory responses. Two types of helper T cell (Th) clones (Th1 and Th2) are defined on the basis of different patterns of cytokine (lymphokine) secretion. They determine the outcome of an antigenic response toward humoral or cell-mediated immunity. Although lymphokine genes are coordinately regulated upon antigen stimulation, they are regulated by the mechanisms common to all as well as those which are unique to each gene. For most lymphokine genes, a combination of phorbol esters (phorbol 12-myristate 13 acetate, PMA) and calcium ionophores (A23187) is required for their maximal induction. Yet phorbol ester alone or calcium ionophore alone produce several lymphokines. The production of the granulocyte-macrophage colony stimulating factor (GM-CSF) is completely dependent on the two signals. We have previously found a cis-acting region spanning the GM-CSF promoter region (positions -95 to +27) that confers inducibility to reporter genes in transient transfection assays. Further analysis identified three elements required for efficient induction, referred to as GM2, GC-box and conserved lymphokine element (CLE0). GM2 defines a binding site for protein(s) whose binding is inducible by PMA. One protein, NF-GM2 is similar to the transcription factor NF-kB. GC-box is a binding site for constitutively bound proteins. CLEO defines a binding site for protein(s) whose optimum binding is stimulated by PMA and A23187. Viral trans-activators such as Tax (human T cell leukemia virus-1, HTLV-1) and E2 (bovine papilloma virus, BPV) proteins are other agents which activate lymphokine gene expression by bypassing T cell receptor (TCR) mediated signaling. The trans-activation domain of E2 and Tax is interchangeable although they have no obvious sequence homology between them. The viral trans-activators appear to target specific DNA binding protein such as NF-kB and Sp1 to cis-acting DNA site and promote lymphokine gene expression without TCR-mediated stimulation.
We investigated the postprandial changes of two species of lipoproteins containing apolipoprotein (apo)A-I: lipoprotein containing apo A-I but no apo A-II (LpA-I), and lipoprotein containing apo A-I and apo A-II (LpA-I/A-II). These lipoproteins were isolated from 10 men and 11 women at 0, 4, and 6 h after they had eaten butter. In LpA-I, the concentrations of all lipids except triglyceride were increased at 4 and 6 h in the women. In the men all lipids were increased only at 4 h. The increase of apo A-I concentration was found at 6 h only in the women. In LpA-I/A-II, the concentrations of all lipids were increased at 4 h and only phospholipid (PL) was increased at 6 h in the women. In the men, free cholesterol and PL were increased at 4 and 6 h. The increases of apo A-I and apo A-II concentrations were found at 4 and 6 h only in the men. These results suggest that the postprandial changes are sex-related and may relate to the different incidence of atherosclerotic cardiovascular disorders.
A tumor in the left thigh of a 1-year-old boy was diagnosed as rhabdomyosarcoma (stage 1). The tumor was excised and vincristine (1.5 mg/m2 given twice), actinomycin D (15 micrograms/kg given five times), and cyclophosphamide (600 mg/m2 given once) were prescribed. On the 12th day after initiating this chemotherapy, his liver rapidly enlarged and ascites, pleural effusion, and disturbance of consciousness due to hepatic failure successively appeared. Before these clinical signs appeared, laboratory data demonstrated enhanced coagulation and fibrinolysis such as thrombocytopenia refractory to platelet transfusion and a marked increase in fibrinogen and fibrin degradation product (FDP). Hepatic veno-occlusive disease (VOD) was suspected, and based on the laboratory data indicating enhanced coagulation, anticoagulant (gabexate mesylate; FOY), diuretic, and supportive therapy for hepatic failure was begun. The clinical course was favorable and recovery was complete in 2 months, with no sequelae. We propose that platelet count, coagulation factor levels, and FDP may be useful for the early detection of VOD, and an anticoagulant drug such as FOY is worthy of consideration for the prevention and treatment of VOD.
This report describes two cases of neonatal adrenal mass detected antenatally by routine ultrasound (US) examination of pregnant women. Case 1 was recognized by the fetal US at 31 weeks gestation. The mass, located near the right upper pole of the kidney, was echolucent on US examination. A serial US of the mass showed changes of the internal echoes from a cystic lesion to a mixed lesion, and finally to a hyperechogenic lesion due to a neonatal adrenal hemorrhage (NAH). At 33 days, laparotomy was performed, and the pathological finding revealed an NAH owing to the mass bleeding into the adrenal cyst. Case 2 was also detected by fetal US just before birth. The mass of the right upper pole of the kidney was hyperechogenic on US examination. The baby clinically deteriorated after birth because of hypovolemia owing to NAH. A serial US of the mass showed the change from a hyperechogenic to a cystic lesion. Four months later, the mass spontaneously resolved. From the US spectrum, the mass was diagnosed as NAH. These are the second known cases of NAH detected before birth in Japan.
Renal tubular reabsorption of phosphate in response to GH administration was studied in 28 short Japanese children, aged 5-11 yr (height SD score, less than -2.0 SD). Three groups included a classical GH deficiency (group 1; n = 12), a partial GH deficiency (group 2; n = 7), and children with non-GH deficiency (group 3; n = 9), depending on the peak response of serum GH in four provocative tests. Serum phosphorus, alkaline phosphatase, insulin-like growth factor-I (IGF-I), osteocalcin, and ratio of the maximum tubular reabsorption rate for phosphorus to the glomerular filtration rate (Tmp/GFR) were all significantly lower in group 1 compared with findings in groups 2 and 3 (P less than 0.05, P less than 0.01, and P less than 0.001). After the administration of GH (0.1 U/kg.day) for 4 consecutive days, increments in serum phosphorus and Tmp/GFR were significantly higher in group 1 than in group 2 (P less than 0.01 and P less than 0.01) or group 3 (P less than 0.01 and P less than 0.01), whereas the increment in IGF-I was similar in all 3 groups, and the levels of serum alkaline phosphatase and osteocalcin remained unchanged in all 3 groups. The calculated ratio of the increment in Tmp/GFR to the increment in IGF-I (delta Tmp/GFR/delta IGF-I) was highest in group 1, intermediate in group 2, and lowest in group 3 (P less than 0.001). One year after the GH treatment (0.5 U/kg.week), height velocity was 7.9 +/- 2.2 cm/yr in group 1 and 5.9 +/- 1.2 cm/yr in group 2; no child in group 3 was treated. When the above calculated parameters, delta Tmp/GFR/delta IGF-I and increment in height velocity (difference between pre- and posttherapy values), were taken into account, there was a significant positive correlation (n = 19; r = 0.78; P less than 0.001). This parameter can be used for purposes of predicting the outcome after 1 yr of GH therapy.
An immunohistochemical analysis of Rhodococcus equi-induced pneumonia in 10 foals was performed by biotin-streptavidin system. The detection of R. equi was more sensitive in immuno-stain using anti-R. equi serum than in Gram's stain. This bacteria also reacted to anti-BCG serum. Lysozyme and alpha 1-antitrypsin were detectable in macrophages. A particularly intense staining was observed in association with intracellular bacteria. Though a degree of reaction for alpha 1-antichymotrypsin was very low in comparison with lysozyme and alpha 1-antitrypsin, it was also demonstrated in macrophages ingesting R. equi. These bacteria were almost intact under an electron microscope. Therefore, the surface components of R. equi may play important roles of protection from intracellular enzymes of macrophages. The cells containing intracytoplasmic IgM, IgG or IgA were a few in number and scattered predominantly around the pneumonic lesion. It is considered that the bactericidal activity by immunoglobulins may be weak in comparison with phagocytosis by macrophages.
A case of isolated angiitis of the central nervous system (IACNS) which first presented as intracranial hemorrhage during cesarean section was reported. The patient was a 27-year-old female who showed severe headache during cesarean section. CT scan disclosed hematoma in the right parieto-occipital area. Carotid and vertebral angiograms demonstrated striking areas of stenosis and irregularity of all intracranial arteries. There was no abnormality in the branches of the external carotid arteries. Systemic angiograms showed no evidence of systemic vasculitis. Biopsy of the temporal artery showed no abnormal findings. Titer of immune complex was elevated. Angiitis showed no improvement with corticosteroid alone, but improved markedly with corticosteroid plus cyclophosphamide. Elevated titer of immune complex became normal. Treatment with a combination of corticosteroid and cyclophosphamide is recommended in IACN.
During the past 5 years, the discovery of cell-free superoxide generation system (Bromberg Y, Pick E: Cell Immunol 88:213-221, 1984) has been revolutionized our understanding of phagocyte superoxide generation. Using cell-free system, it was clarified that NADPH oxidase for superoxide generation was comprised of components present in both the plasma membrane as well as in the cytosol. This oxidase could be kept inactive by keeping its components separated from each other within the cell and then quickly bringing them together in the plasma membrane upon activation. We analyzed cytosol components with column method, and clarified that 3 neutrophil cytosol factors (NCF-1/-2/-3) was necessary for reconstitute the cytosol activity which was missing in an autosomal recessive type of Chronic Granulomatous Disease (CGD) patients (Nunoi H, et al:Science 242:1298-1301, 1988). NCF-1/-2 were analyzed with B1 antibody and found their molecular weight as 47 and 67 kilodalton respectively. One of autosomal CGD patients was missing NCF-67k and the others were missing NCF-47k. NCF-47k and -67k were cloned with this antibody and sequenced and expressed as recombinant NCF-47k/-67k using baculovirus/insect cell system. Using these recombinants, we are trying to purify NCF-3 which is reported as small G protein in these days. Using monoclonal antibodies against these recombinants, we analyzed tissues with immunohistochemical methods and are trying to classify the type of CGD patients in Japan. In summary, at least five oxidase components now have been identified (alpha and beta chain of cytochrome b558 (gp91-phox, p22-phox) and NCF-47k/-67k/-3 (p47-phox/p67-phox/delta-1 or SOCI)).
Argininemia is caused by a hereditary deficiency of liver-type arginase (E.C.3.5.3.1) and is characterized by psychomotor retardation and spastic tetraplegia. We examined findings in three Japanese patients with argininemia, by using the PCR, cloning, and sequencing procedures. We found three different mutations--G-to-A-365 in exon 4, G-to-C-703 in exon 7, and C-del-842 in exon 8--thereby leading to mutant arginase proteins of W122X, G235R, and L282FS, respectively. Patient 1 was a compound heterozygote, inheriting the allele with G-to-A-365 from his mother and the allele with G-to-C-703 from his father. Patients 2 and 3 were homozygotes of the allele with G-to-C-703 and of the allele with C-del-842, respectively. Expression tests of these mutant arginases in Escherichia coli indicated that the mutant arginase of W122X did not remain a stable product. The other two mutant arginases--G235R and L282FS--were detected by immunoblot analyses. There was no evidence of activity of the three mutant arginases expressed in E. coli. We tentatively conclude that argininemia is heterogeneous, at the molecular level.
We studied clinicopathologically 19 patients with abnormal urinary findings accompanying with persistent hypocomplementemia under age 15. They consisted of 6 patients with membranoproliferative glomerulonephritis (MPGN) type I, 2 with MPGN type II, 2 with focal MPGN, 8 with diffuse proliferative glomerulonephritis (DPGN), 1 with focal glomerulonephritis (FGN). 17 cases were treated with steroid. In 2 patients with MPGN type I and 1 patient with DPGN, the treatment resulted in normalization of serum C3 level and urinary abnormalities and improvement of histological findings. In 3 patients with DPGN, urinary abnormalities and hypocomplementemia have been persisted and histological findings changed to those of MPGN type I. Thus, DPGN with hypocomplementemia seems to be an early stage of MPGN type I.
Recent progress in the molecular biological approach to analysis of inherited tubular transport abnormalities is reviewed. 1) cDNAs of several mammalian proteins, related to amino acid transport in renal tubular cell, have been cloned using an expression cloning in Xenopus oocytes. One of them stimulates the transport of cystine, dibasic amino acids and neutral amino acids and will accelerate the analysis of cystinuria. 2) Isolation of cDNAs, encoding human and rat vasopressin V2 receptors, has been reported. The deduced amino acid sequence seems to be a member of receptors with seven putative transmembrane regions. Analysis of this gene from patients with nephrogenic diabetes insipidus is in progress. 3) Analysis of carbonic anhydrase II (CA II) gene in a Belgian family with renal tubular acidosis associated with osteoporosis and cerebral calcification has shown a point mutation replacing an invariant histidine residue of CA II protein with tyrosine. 4) Oculocerebrorenal syndrome of Lowe (OCRL) is a X-linked disorder affecting the lens, brain and kidneys. The OCRL locus has been mapped to Xq24-26 by linkage analysis and by finding de novo X-autosome translocations at Xq24-26 in two unrelated females with OCRL. A cDNA has been isolated using yeast artificial chromosome and DNA inserts that span the X chromosome breakpoint from a female patient. Transcript for this cDNA is absent in unrelated male patients. The open reading frame encodes a new protein similar to human inositol-polyphosphate-5-phosphatase, raising a possibility that OCRL is an inborn error of inositol phosphate metabolism.
A 55-year-old man with a mild fever and sweating developed severe headache for the days before admission. Cerebral computed tomography and selected cerebral angiography on the day of admission revealed subarachnoid hemorrhage due to rupture of an aneurysm of a distal branch of the left middle cerebral artery. Detection of vegetation on the aortic valve by two dimensional echocardiography confirmed the diagnosis of infective endocarditis with a ruptured mycotic cerebral aneurysm. Because of rapid growth of the vegetation on the aortic valve and progression of heart failure despite antibiotic therapy, emergency cardiac surgery was performed. To prevent re-rupture of the aneurysm, the aortic valve was replaced with a bioprosthetic valve, and no anticoagulant was administered postoperatively. Repeated cerebral angiography revealed that the aneurysm was becoming progressively smaller during the next 9 months. No cerebrovascular accident occurred postoperatively. We believe that it is safe to treat a ruptured mycotic cerebral aneurysm without involvement of a hematoma mass in the brain conservatively, and that use of a bioprosthetic valve, if valve replacement is mandatory, and avoidance of anticoagulant therapy during the postoperative period are advisable in the treatment of a patient with infective endocarditis and a ruptured cerebral mycotic aneurysm.
We report herein data on 6 male patients with progressive tubulopathy. These patients belonged to two families: the propositus, his father, a paternal first cousin, two paternal uncles, and a maternal uncle. A 7-year-old proband had mild proteinuria (1 g/day), consisting of beta 2-microglobulin, alpha 1-microglobulin and lysozyme, and aminoaciduria. Glycosuria and acidosis were absent. A 38-year-old father had mild proteinuria (2 g/day), including low-molecular-weight protein. Hypokalemia, hypophosphatemia, glucosuria, phosphaturia, aminoaciduria, and reduced urinary concentrating ability were also present. The other 4 affected family members also had low-molecular-weight proteinuria, detected by screening for beta 2-microglobulin. In addition, there were several abnormalities; aminoaciduria in all 6, phosphaturia in 4 of 6, hypercalciuria in all 6 and glycosuria in 2 of 6 patients. Tubular dysfunction was more severe in the older subjects, hence, the disease seems to progress with age. Familial low-molecular-weight proteinuria is apparently a progressive disease linked to a X-linked or to an autosomal dominant inheritance.
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Carbamyl phosphate synthetase I (CPSI) is the first enzyme involved in urea synthesis. CPSI deficiency is an autosomal recessive disorder characterized by hyperammonemic coma in the neonatal period. To analyze the enzyme and gene structures, and to elucidate the nature of mutations in CPSI deficiency, we isolated cDNA clones encoding human liver CPSI. Oligo(dT)-primed and random primer human liver cDNA libraries in lambda gt11 were screened using 5', middle, and 3' fragments of the rat CPSI cDNA as probes. Seven positive clones covered the full-length cDNA sequence with an open reading frame encoding a precursor polypeptide of 1500 amino acids (aa) (deduced Mr, 164,828) with a putative N-terminal presequence of 38 or 39 aa, a 5'-untranslated sequence of 118 bp and a 3'-untranslated sequence of 597 bp. Comparison with the rat CPSI cDNA showed that the deduced aa sequence of the human liver CPSI precursor is 94.4% identical to the rat enzyme precursor. A molecular analysis was made of the genomic DNA from three patients with CPSI deficiency. Heterogeneity of hybridized fragments that may or may not be the cause of the deficiency was apparent on the DNA blots from tissues from one patient.
We analyzed neurological data, including DQ or IQ, EEG, and CT scan, in 49 patients with urea cycle enzymopathies, all of whom were included in a retrospective survey from 1978-1988 in Japan. We classified 3 groups depending on age-at-onset: group 1 (0-28 days, N = 11), group 2 (29 days-5 years, N = 31), and group 3 (greater than 5 years, N = 7). The least DQ or IQ score and the highest CT score, representing the most severe brain damage was found in group 1, and the highest DQ or IQ and the least CT score was found in group 3. Intermediate scores of both parameters were found in group 2. There was a negative correlation between these 2 parameters (r = -0.82, P less than 0.01). Abnormal EEG during the attack-free period was predominantly observed in patients with CT abnormalities compared to those with a normal CT scan (P less than 0.01). Approximately 40% of the patients, mostly in groups 2 and 3 (92.8%) had normal findings in all 3 parameters. Thus, the magnitude of developmental abnormalities is clearly related to the degree of brain damage and to the age-at-onset of these diseases.