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K Fujieda

Publications and source records attributed to K Fujieda.

At least 55 records · Page 3Linked to original sources
PubMed1997

Analysis of the steroidogenic acute regulatory protein (StAR) gene in Japanese patients with congenital lipoid adrenal hyperplasia.

Genomic DNA from 19 Japanese patients with congenital lipoid adrenal hyperplasia (lipoid CAH) representing 16 different families was examined to identify the genetic alterations of steroidogenic acute regulatory protein (StAR). Ten of 19 patients had a 46,XX karyotype and nine had a 46,XY karyotype. Six of the 46,XX patients have experienced spontaneous pubertal changes including breast development and irregular menstruation whereas none of the 46,XY subjects displayed pubertal changes. Eight different mutations were identified. Sixteen patients were either homozygotes or compound heterozygotes for the Q258X mutation. The seven other mutations identified were 189delG, 246insG, 564del13bp, 838delA, Q212X, A218V and M225T. The 189delG, 246insG, 546del13bp and Q212X mutants encode truncated proteins. COS-1 cells transfected with expression vectors encoding cDNAs for the mutant StAR proteins which affect the C-terminus, 838delA, A218V and Q258X, exhibited no steroidogenesis enhancing activity. However, the M225T mutant retained some steroidogenic activity. The patient with the M225T mutation had late onset of this disorder and some capacity to secrete testosterone in response to hCG. These findings suggest: (i) that the Q258X mutation can be used as a genetic marker for the screening of Japanese for lipoid CAH, (ii) that the C-terminus of StAR plays an important role in the protein's activity and (iii) that there are differences in the extent of functional impairment of the testis and ovaries in lipoid CAH.

Adrenal Hyperplasia, Congenital↗
PubMed1997

No genetic mutation in type II 3 beta-hydroxysteroid dehydrogenase gene in patients with biochemical evidence of enzyme deficiency.

Nonclassic or the mild form of 3 beta-hydroxysteroid dehydrogenase (NC3 beta-HSD) deficiency is an entity which is identified with typical features of premature pubarche, hirsutism, or oligomenorrhea. In this study, type II 3 beta-HSD gene from 4 girls who were diagnosed as NC3 beta-HSD deficient, base on the adrenal steroidogenic responses to ACTH, was analyzed to determine whether NC3 beta-HSD deficiency was an allelic variant of classical 3 beta-HSD deficiency by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). We could not detect any alterations of type II 3 beta-HSD gene from these patients. Our result strongly suggests that unlike classical 3 beta-HSD deficiency, NC3 beta-HSD deficiency may be secondary adrenal biosynthetic defects, rather than dual inherited deficiencies.

Adolescent↗
PubMed1997

Pubertal changes in testicular 3 beta-hydroxysteroid dehydrogenase activity in a male with classical 3 beta-hydroxysteroid dehydrogenase deficiency showing spontaneous secondary sexual maturation.

Males with classical 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) deficiency manifest appropriate secondary sexual maturation with an elevation in serum testosterone levels at pubertal age. To define the origin of serum testosterone, we evaluated a male patient with classical 3 beta-HSD who showed pubertal development. High values of testosterone and a ratio of delta(5) to delta(4) steroids in the spermatic vein indicated direct production of considerable amounts of testosterone and a persistent defect of 3 beta-HSD activity in the gonad. Immunohistochemical analysis showed distinct immunoreactivity in the Leydig cells of the patient. The patient was homozygous for a nonsense mutation in the type-II 3 beta-HSD gene. We propose that gonadal type-I 3 beta-HSD could be expressed by gonadotropin stimulation at pubertal age, and delta(4)-steroid precursors would convert to testosterone.

3-Hydroxysteroid Dehydrogenases↗
PubMed1997

Three novel mutations and a de novo deletion mutation of the DAX-1 gene in patients with X-linked adrenal hypoplasia congenita.

The DAX-1 [DSS (dosage sensitive sex)-AHC critical region on the X, gene 1] gene is responsible for X-linked adrenal hypoplasia congenita (AHC). However, DAX-1 protein structure-function relationships are not well understood. Identification of missense mutations may help to reveal these relationships. We analyzed the DAX-1 gene from seven patients in six kindreds with X-linked AHC and identified one frameshift mutation, two missense mutations, and three deletion mutations. Case 1 had a 388delAG frameshift mutation, inducing a premature stop codon at position 70. Case 2 had a missense mutation, Lys382Asn, which encodes an asparagine (Asn) for lysine (Lys) at position 382. Sibling cases of 3-1 and 3-2 had a missense mutation of Trp291 Cys, which encodes a substitution of cysteine (Cys) for tryptophan (Try) at position 291. The tryptophan (Trp) at position 291 and lysine (Lys) at position 382 in human DAX-1 protein are highly conserved among other related orphan nuclear receptor superfamily members. Cases 4, 5, and 6 showed deletion mutation. In case 6, a de novo deletion mutation was revealed by both southern hybridization and polymerase chain reaction (PCR) of a GGAA tetranucleotide tandem repeat. These findings suggest that: 1) Trp at position 291 and Lys at position 382, located in the C-terminal presumptive ligand binding domain, are important to the functional role of the DAX-1 protein in adrenal embryogenesis and/or in hypothalamic-pituitary activity; and 2) molecular analysis of the DAX-1 gene may help genetic counseling, even in cases with deletion mutation, because a detection of de novo deletion may exclude another affected or carrier child.

Adrenal Insufficiency↗
PubMed1997

Molecular basis of nonclassical steroid 21-hydroxylase deficiency detected by neonatal mass screening in Japan.

Since 1989, neonatal mass screening for congenital adrenal hyperplasia (CAH) has been performed in Japan, and the frequency of the classical form of 21-hydroxylase deficiency was found to be nearly identical to that in other countries. However, it has not yet been determined whether our mass screening program can detect the nonclassical (NC) form. From 1991 to 1994, about 4,500,000 infants underwent CAH mass screening in Japan. During this period, we identified by screening 2 siblings and 2 unrelated patients who had mild elevation of serum 17-hydroxyprogesterone levels at 5 days of age, but who revealed no symptoms of CAH. They were diagnosed as having probable NC steroid 21-hydroxylase deficiency. To clarify the molecular basis of NC CAH detectable by neonatal screening in Japan, the steroid 21-hydroxylase (CYP21) genes from these cases were analyzed. The 2 siblings (patients 1 and 2) had I172N and R356W mutations in 1 allele and in the other allele had local gene conversion, including the P30L mutation in exon 1. Patient 3, who was unrelated, had gene conversion encoding the same P30L mutation in 1 allele and in the other allele had an intron 2 mutation (668-12 A-->G), causing aberrant ribonucleic acid splicing, and the R356W mutation. Patient 4, also a compound heterozygote, had the R356W and 707del8 mutations. The estimated rate of detection of the NC form by mass screening (1:1,100,000) seemed low compare to the established detection rate for the classical form (1:18,000). As all of our 4 patients were compound heterozygotes with at least 1 allele bearing 1 or more mutations associated with classic CAH, it may be difficult to detect NC cases carrying only NC-associated alleles using our current neonatal mass screening methods.

17-alpha-Hydroxyprogesterone↗
PubMed1997

Conventional molecular diagnosis of steroid 21-hydroxylase deficiency using mismatched primers and polymerase chain reaction.

We tested a conventional method based on polymerase chain reaction (PCR) and specific primers with one mismatched base at the 3' end to introduce restriction enzyme sites in order to detect mutations of the CYP21 gene without radioisotope. Using this method, the intron 2 mutation causing aberrant splicing of mRNA (In2G) and the exon 4 mutation (Ile->Asn, Ex4) in the CYP21 gene were analyzed. The nonsense mutation in exon 8 (Ex8NON) of the CYP21 gene was also investigated by PCR and subsequent restriction enzyme digestion. The mismatched primers successfully amplified the CYP21 gene containing the In2G and the Ex4 mutation sites, and the presence of these two mutations could be determined by restriction enzyme digestion after PCR. We used this new method to study 33 patients. Twenty-five of these patients were found to have at least one mutation (In2G and/or Ex4 mutation). By enzyme digestion after PCR, the Ex8NON mutation was also identified (7 out of 33 patients). In conclusion, we have developed a new method to detect point mutations in the CYP21 gene. This method was proved to be sensitive and rapid for the detection of the mutations studied. Therefore, this method is suitable for clinical genetic diagnosis.

Adrenal Hyperplasia, Congenital↗
PubMed1996

Pathophysiologic significance of left ventricular hypertrophy in dilated cardiomyopathy.

BACKGROUND AND HYPOTHESIS: Patients with dilated cardiomyopathy (DCM) with left ventricular hypertrophy (LVH) have been found to have a better prognosis than patients without LVH. However, the pathophysiologic mechanism for that has not been investigated. We sought to clarify the pathophysiologic significance of LVH in DCM. METHODS: We performed isoproterenol infusion echocardiography (0.02 micrograms/kg/min) in 17 patients with DCM, and measured plasma epinephrine and norepinephrine levels at rest and at the end of ergometer exercise in 14 of the 17 patients. Patients were classified into groups according to the presence (9 patients) (LVH+) or absence (8 patients) (LVH-) of LVH. Left ventricular hypertrophy was defined as an inter-ventricular thickness or posterior wall thickness > or = 13 mm. RESULTS: Although there was no significant difference between groups in fractional shortening at rest during isoproterenol infusion, fractional shortening was significantly higher in the LVH(+) group than in the LVH(-) group (29 +/- 9 vs. 17 +/- 8%; p < 0.025). Although there was no significant difference in plasma norepinephrine level, it was significantly lower in the LVH(+) group than in the LVH(-) group (233 +/- 169 vs. 519 +/- 258 pg/ml; p < 0.05) at the end point of the exercise. CONCLUSION: Systolic reserve, represented by the response to isoproterenol, is greater in patients with DCM with LVH than in those without LVH, and a lower plasma level of norepinephrine is needed to activate the myocardium during exercise in patients with DCM with LVH. This pathophysiologic characteristic could be one of the mechanisms which explain a better prognosis in patients with DCM with LVH.

Adult↗
PubMed1996

Three novel AVPR2 mutations in three Japanese families with X-linked nephrogenic diabetes insipidus.

We identified three novel mutations of the arginine vasopressin (AVP) V2 receptor (AVPR2) gene in Japanese families with X-linked congenital nephrogenic diabetes insipidus (NDI). In kindred #1 of siblings, a single base deletion of one out of three guanosines (nucleotides 786-788, 786delG) was detected. This deletion shifts the reading frame with an altered amino acid sequence and introduces a premature stop codon (TGA) at position 270. In kindred #2 of siblings and one unrelated additional patient (patient #3), point mutations that change the same Pro residue at codon 322 in the seventh transmembrane domain to either a Ser or His (P322S or P322H) were detected. This P322 residue is well conserved among rat V1 and V2 receptors, the human oxytocin receptor, and other G protein-coupled receptors, and is thought to be important for proper insertion of the receptor into the membrane. The AVPR2 mutations are heterogeneous both in Japanese and Caucasians populations.

Arginine Vasopressin↗
PubMed1996

Truncation at the C-terminus of the DAX-1 protein impairs its biological actions in patients with X-linked adrenal hypoplasia congenita.

The DAX-1 [DSS (dosage-sensitive sex)-AHC critical region in the X, gene 1] gene has been reported to be responsible for X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism. However, the function and structure of the DAX-1 protein have not been characterized. In this study, molecular analysis of the DAX-1 gene from 6 patients with AHC, including 2 siblings, identified 5 novel mutations with 3 nonsense mutations and 2 frameshift mutations. Case 1 had a nonsense mutation at position 395 (Q395X). Cases 2 and 3, who were siblings, had a nonsense mutation at position 91 (Y91X). Case 4 had a 2-base deletion (AT) at nucleotides 1610 and 1611 and a 1-base insertion (G) resulting in a premature stop codon at position 462 (1610-1611 del AT ins G). Case 5 had a nonsense mutation at position 271 (Y271X). Case 6 had a 1-base deletion (C) at nucleotide 1169, which induced a frame shift and a premature stop codon at position 371 (1169 del C). All mutated DAX-1 proteins had truncated C-terminal domains. In addition, reverse transcription-PCR and direct sequencing characterized the mutant messenger ribonucleic acid in testis from case 1. Our results suggest that these 5 novel mutations are responsible for X-linked AHC and that the C-terminus of the DAX-1 protein, especially the terminal 11 amino acids, is necessary for normal adrenal cortical embryogenesis.

Adolescent↗
PubMed1996

Growth response to growth hormone therapy in patients with different degrees of growth hormone deficiency.

Growth response to GH therapy in prepubertal patients with idiopathic GH deficiency (GHD) was analyzed in terms of the chronological age at the start of GH treatment and the GH secretory capacity, by using the large database provided by the International Cooperative Growth Study (ICGS) Japan. 1192 patients, aged from 3 to 10 years were divided into three groups with the following maximum GH values in GH stimulation tests: Group A: both < or = 5 ng/ml, group B: both 5-10 ng/ml, group C: one > 10 ng/ml. Analysis of age-related growth response using with delta height SDS (delta height SDS) as a response variable revealed that the group A patients responded better to GH, while there was no differences between the other groups. Simple and multiple regression analysis showed that IGF-I and chronological age (CA) negatively correlated with growth response, and target height SDS-height SDS positively correlated. These three most important predictors accounted for 49% of the variation in the growth response in group A, whereas six variables such as CA, frequency of GH injection, % overweight, GH dose, target height-height SDS, and pretreatment height velocity SDS accounted for only 28% of those in groups of B and C. These results lead us to conclude that growth response to GH is related to the degree of GH impairment with its cut-off level of 5 ng/ml. From these findings it might be suggested that treatment regimen should be tailored to individual requirements according to the degree of GHD.

Aging↗
PubMed1995

Replacements of leucine 87 in human insulin receptor alter affinity for insulin.

In a previous analysis, we identified a point mutation that substituted Pro (CCG) for Leu (CTG) at amino acid 87 in the alpha-subunit of the insulin receptor (IR) in a Japanese patient with leprechaunism. In the present study, we transfected either the wild type (Leu-87) or the mutant (Pro-87) IR cDNA into NIH3T3 cells. Pulse-chase in nonreducing conditions revealed that the dimerization of Pro-87 IR was slightly impaired. However, cell surface biotinylation showed that Pro-87 IR was transported to the cell surface. The Pro-87 IR reduced the insulin binding affinity to about 15% of Leu-87 IR, and the dissociation of insulin in Pro-87 IR was more rapid than in Leu-87 IR. The autophosphorylation of Pro-87 IR was less sensitive to insulin than that of Leu-87 IR, suggesting the reduced insulin binding affinity. Site-directed mutagenesis at amino acid 87 was performed to substitute Ile or Ala for Leu. Both mutant IRs were transported to the cell surface and labeled by cell surface biotinylation. The Ile-87 IR enhanced the insulin binding affinity about 4-fold. The insulin binding affinity of Ala-87 IR was reduced by 85% relative to that of Leu-87 IR. In addition, the dissociation of insulin in Ile-87 IR was slower than in Leu-87 IR, but in Ala-87 IR it was more rapid. These results provide the first direct evidence for a critical role of Leu-87 in binding insulin.

3T3 Cells↗
PubMed1995

Response to isoproterenol as a prognostic indicator of evolution from hypertrophic cardiomyopathy to a phase resembling dilated cardiomyopathy.

OBJECTIVES: We sought to assess whether isoproterenol stress echocardiography could detect in advance in which patients hypertrophic cardiomyopathy would progress to a phase resembling dilated cardiomyopathy. BACKGROUND: In a few patients, hypertrophic cardiomyopathy has been reported to progress to a phase characterized by systolic dysfunction and left ventricular dilation, resembling dilated cardiomyopathy. METHODS: Echocardiograms were recorded before and immediately after intravenous infusion of isoproterenol (0.02 microgram/kg body weight per min) for 5 min in 18 patients with typical hypertrophic cardiomyopathy (i.e., hypertrophied, hyperdynamic and nondilated) to determine the difference in fractional shortening. The patients were categorized into those with a good response (difference in fractional shortening > 7%, 14 patients) and those with a poor response (difference < or = 7%, 4 patients). Changes in left ventricular end-diastolic diameter and fractional shortening were evaluated by using serial echocardiography over an average follow-up period of 5.4 years. RESULTS: In the good response group, neither end-diastolic diameter nor fractional shortening changed significantly during the follow-up period. In the poor response group, end-diastolic diameter significantly increased from a mean +/- SD of 41 +/- 5 to 53 +/- 5 mm (p < 0.05), and fractional shortening significantly decreased from 40 +/- 12% to 29 +/- 10% (p < 0.05). All patients in the poor response group showed a substantial decrease (> or = 5%) in fractional shortening and an increase (> or = 5 mm) in end-diastolic diameter. One patient developed congestive heart failure due to systolic dysfunction during the observation period. CONCLUSIONS: The present study confirmed that impaired responses to isoproterenol infusion are related to future deterioration of left ventricular performance in patients with typical hypertrophic cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed1995

Predominance of the mutation at 1138 of the cDNA for the fibroblast growth factor receptor 3 in Japanese patients with achondroplasia.

Fibroblast growth factor receptor 3 (FGFR3) has recently been identified as a putative gene for achondroplasia. Since a guanine to adenine mutation at 1138 of the cDNA for FGFR3 had been identified in most of the patients in Western population, we examined 13 Japanese patients to see if they also share the same mutation. Specific endonuclease digestion of the amplified coding sequence for the transmembrane domain of the FGFR3 revealed that the 12 patients have the G to A change at 1138, while the other had the G to C substitution at the same point, both of which result in G380A substitution. As far as we studied, the homogeneity of the point mutation at 1138 is also authentic to Japanese patient as well as Western patients.

Achondroplasia↗
PubMed1995

The diversity of left ventricular responses to isoproterenol and dibutyryl cyclic AMP infusion in patients with dilated cardiomyopathy.

Sixteen patients with dilated cardiomyopathy were studied to define the abnormality of the beta-adrenergic pathway non-invasively, using echocardiographic left ventricular responses to isoproterenol (ISP; 0.02 microgram/kg/min) and dibutyryl cyclic AMP (DBcAMP; 0.1 mg/kg/min) infusion. The increase in fractional shortening induced by ISP (delta FS-ISP) was 9 +/- 6% and that by DBcAMP (delta FS-DBcAMP) was 7 +/- 3%. The patients could be divided into three groups according to their left ventricular response to each agent: Group A; normal response to ISP (delta FS-ISP > or = 11%), Group B-1; poor response to ISP but better response to DBcAMP (delta FS-ISP < 11%, delta FS-DBcAMP > or = 7%; damage to beta-receptors), and Group B-2; poor response to ISP and DBcAMP (delta FS-ISP < 11%, delta FS-DBcAMP < 7%; damage including post receptor levels). Seven patients were in Group A, four in Group B-1, and five in Group B-2. DCM patients had a diversity of left ventricular responses to ISP and DBcAMP, according to the site of damage in the beta-adrenergic pathway.

Adult↗
PubMed1994

Decreased adrenergic response in hypertensive patients without left ventricular hypertrophy.

To analyze the adrenergic responses and to compare them between hypertensive patients with and without left ventricular hypertrophy (LVH), left ventricular (LV) fractional shortening (FS) and end-systolic wall stress (ESS) were measured by echocardiography and the inotropic response to the infusion of isoproterenol (0.02 micrograms/kg/min for 5 min) was studied in 25 hypertensive patients without LVH [H(-)] and 30 hypertensive patients with LVH [H(+)]. LVH was determined by echocardiography. Age, gender, heart rate, systolic and diastolic blood pressures, LV end-systolic and end-diastolic diameters, and FS were matched between the groups. The tests were performed before introduction of antihypertensive treatment or 4 weeks after its discontinuation. ESS showed a significant inverse linear relation with FS in all the subjects before isoproterenol infusion. The inotropic response to isoproterenol was measured as the increase of FS corrected for the decrease of ESS (delta FS/-delta ESS), that is, the slope of the change of the relation between FS and ESS. The change in delta FS/-delta ESS was significantly smaller (0.49 +/- 0.15 cm2/g, mean +/- SD) in H(-) than in H(+) patients (1.01 +/- 0.57 cm2/g) (p < 0.001). It is concluded that, compared with the H(+) group, adrenergic response is depressed in H(-) patients. This depression might be etiologically related to the phenomenon that LVH did not develop in the H(-) group in spite of the same level of pressure load as in the H(+) group.

Adult↗