Biomedical subjects
Publications and source records attributed to N Sakura.
A retrospective survey was performed between 1983 and 1995 to determine the frequency of steroid sulfatase (STS) deficiency in Hiroshima. Males with ichthyosis were diagnosed enzymatically. During 1979-95 in Hiroshima Prefecture, 275,943 males were born and 28 had STS deficiency. The observed frequency of STS deficiency was 1 per 9855 males. Therefore, STS deficiency is fairly prevalent in Japan.
The fetal diagnosis of galactosialidosis is performed by measuring carboxypeptidase (cathepsin A) activity in cultured villous cells and by immunofluorescence analysis with an antibody against an oligopeptide corresponding to the N-terminal domain of the human mature protective protein. Neither carboxypeptidase activity nor immunofluorescence was detected in cultured villous cells derived from an at-risk fetus or in cultured fibroblasts derived from the sister with galactosialidosis. Neuraminidase and beta-galactosidase activities were also confirmed to be deficient or low. A direct assay system for protective protein/cathepsin A is useful for the accurate prenatal diagnosis of galactosialidosis.
We evaluated the circadian rhythms in the plasma concentrations of cortisol, cortisone and their free forms, and in the cortisone/cortisol ratios by means of reversed-phase high performance liquid chromatography in normal adult subjects. Plasma concentrations of cortisone, as well as cortisol, exhibited a circadian rhythm. The ratios of cortisone/cortisol remained almost constant during the waking hours of normal subjects. Changes in the cortisone/cortisol ratios previously reported in patients with various diseases exceeded the diurnal changes detected in the present study. Thus, the determination of the cortisone/cortisol ratio provides information that is useful in assessing the adrenal function of patients with various diseases.
UNLABELLED: The existence of adrenal dysfunction in asthmatic patients remains controversial. Assessing adrenal function in these patients is difficult because of varying severity and duration of attacks and large fluctuations in the secretion of adrenocortical hormones. Total and free (unbound) levels of serum cortisol and cortisone were measured in asthmatic children and healthy controls using reversed-phase high performance liquid chromatography. The results were correlated with the severity and duration of asthma attacks. In asthmatic patients in remission, total and free concentrations of cortisol and cortisone did not differ significantly from those in healthy controls. During attacks, levels increased in proportion to the severity of the attack. These values decreased to control levels after 24 h. However, in children with attacks lasting for more than 5 days, values remained significantly decreased with no relation to the severity of the attack. CONCLUSION: During an asthma attack, adrenocortical hormone concentrations increase in proportion to the severity of the attack but subsequently decrease with time. It is speculated that the inability to sustain an elevated cortisol level may lead to the persistent asthma attacks.
UNLABELLED: To determine whether plasma levels of total bile acids may provide a useful index for hypergalactosaemia due to porto-systemic shunts, these levels were determined in hypergalactosaemic neonates. Increased levels were found in all cases with portohepatic venous or portocaval shunts. The levels of both total bile acids and galactose were normalized when the shunts disappeared on the echograms. Both bile acids and galactose are almost completely absorbed by the liver via the first portal blood passage. Portosystemic shunts contribute to elevated levels of bile acids and galactose. CONCLUSION: Increased plasma levels of total bile acids serve as a diagnostic clue to the presence of portosystemic shunts in neonates with hypergalactosaemia.
Plasma total homocysteine (tHcy) and serum folate (FA) concentrations were measured in 130 epileptic patients taking anticonvulsant drugs. A significant inverse correlation was found between FA and tHcy. This was greater in the older group (> or = 15 years) than in the younger group (1 to 14 years). There were four FA-deficient patients (FA concentration < 3 ng/mL regardless of symptoms), including three patients in the older group and one in the younger group. All FA-deficient patients had received long-term treatment (> 7 years) with multiple anticonvulsants. Their tHcy levels were higher than the 90th percentile of those in control subjects. Two patients showed extremely high levels of tHcy (57.9 and 29.1 mumol/L) and subnormal plasma methionine levels. After FA therapy, their tHcy decreased to levels the same as or less than those of control subjects and FA increased to above the normal range. Based on these findings, we conclude that measuring FA and tHcy concentrations may be useful for preventing thrombosis due to hyperhomocysteinemia in epileptic patients taking anticonvulsants, particularly those who receive long-term treatment with multiple agents.
To determine the relationship between biological active cortisol and its inert metabolite cortisone accurately in premature infants, serum cortisone and cortisol concentrations were measured by reversed-phase high-performance liquid chromatography (HPLC) in a group of 232 premature infants and in a control group of 127 children and 88 adults. In the control group, serum cortisone concentrations were greater than serum cortisol levels during the first 2 months after birth; cortisol levels were higher than cortisone levels after 2 months of age. However, in premature infants, serum cortisone concentrations were greater than serum cortisol levels even after the first 2 months, and total concentrations of cortisone and cortisol were equal to those in controls. Results were then analyzed according to the equivalent gestational age of premature infants. Cortisone was predominant in premature infants older than 32 weeks of equivalent gestational age, but cortisol was higher than cortisone from equivalent gestational age 24 to 31 weeks. These findings suggest that the ability of premature infants to secrete glucocorticoids resembled that of normal controls. Also, the fetal zone of the cortex, which is associated with a predominance of cortisone, remained functional in premature infants for a longer time than in control infants. Our findings that in premature infants cortisone was predominant compared with cortisol and the sum of cortisone and cortisol was equal to that in the controls indicate that cortisone cannot be disregarded whenever the cortisol level is estimated, although cortisone itself is recognized to be biologically inactive. Simultaneous measurement of serum cortisone and cortisol concentrations is important when adrenocortical function is being determined, especially in premature infants.
Pearson marrow-pancreas syndrome, a fatal disease associated with mitochondrial DNA rearrangements, is characterized by refractory sideroblastic anaemia during infancy. Only a few neonates with Pearson syndrome have been reported with metabolic acidosis. A female neonate who exhibited severe metabolic acidosis and anaemia at birth is described here. Her condition progressively worsened, with pancytopenia and uncontrollable metabolic acidosis resulting in death at the age of 14 days. A 4988-base pair deletion of mtDNA was detected in the patient's leukocytes, liver and muscle. When a neonate exhibits severe metabolic acidosis of unknown cause, the possibility of Pearson syndrome should be considered.
Ten of 31 patients with steroid sulphatase (STS) deficiency were found to have an allergic disease (bronchial asthma, allergic rhinitis, or atopic dermatitis). STS deficiency may predispose patients to allergic disease.
We studied the proportion of deleted mitochondrial DNA in blood cells from patients with Pearson syndrome. Patient 1 is a 17-year-old female with Kearns-Sayre syndrome who survived Pearson syndrome. Patient 2 is a 5-year-old boy with Pearson syndrome who recovered from refractory anaemia but continues to have thrombocytopenia and neutropenia. Patient 3 is a female neonate who died with severe acidosis and pancytopenia at 14 days of age. Southern blot analysis was performed with total DNA from three patients' blood cells and two samples of bone marrow cells from one patient. In peripheral blood, patients with a higher proportion of deleted mitochondrial DNA had lower blood cell counts. In patient 2, the percentage of mutant mitochondrial DNA in bone marrow cells decreased as anaemia improved. This indicates that the proportion of deleted mitochondrial DNA in peripheral blood and in bone marrow has a tendency to correlate to the severity of haematological manifestation.
Cortisone is derived from the peripheral metabolism of cortisol and lacks biological activity. The rapid interconversion between cortisol and cortisone has been well established. The altered equilibrium between these steroids may regulate glucocorticoid activity in various tissues. We evaluated the serum levels of cortisol and cortisone, and the cortisone/cortisol ratio in ten children with adrenal diseases using reversed-phase high performance liquid chromatography. Children with hypoadrenalism exhibited a greater decrease in cortisol as compared with cortisone. Cortisone levels were higher than cortisol levels, and the cortisone/ cortisol ratio exceeded 1.0. Children with adrenal cancer exhibited normal or high values of cortisol, whereas cortisone levels were decreased and the cortisone/cortisol ratio was decreased to nearly zero. The ratio returned to normal after the excision of adrenal tumors. The simultaneous evaluation of cortisol, cortisone, and cortisone/cortisol ratio provides a clinical clue of adrenal diseases.
Although genotype-phenotype correlations in male patients with various types of nullisomy for Xp22.3 have assigned a locus for X-linked mental retardation (MRX) to an approximately 3-Mb region between DXS31 and STS, the precise location has not been determined. In this paper, we describe a 14 7/12 year old Japanese boy with mental retardation and an interstitial deletion at Xp22.3 involving STS, KAL1, and OA1, and compare the deletion map with that of previously reported three familial male patients with low-normal intelligence and a similar interstitial deletion at Xp22.3. The results suggest that the MRX gene is further localized to the roughly 1.5-Mb region between DXS1060 and DXS1139.
We studied the susceptibility of the pyrrolidone moiety and the pyroglutamyl-peptide bond at pGlu-X-Ala-Phe-OH (X = Gly, Ala, Tyr, Ile, Pro, His, Lys, Arg, Thr, Ser, Asp, Glu and Trp) to 1 N HCl or 2 M trifluoromethanesulfonic acid at 60 degrees C. Here we describe the rates of the cleavage reaction of the pGlu-X bond, the pyrrolidone ring-opening reaction of the pGlu moiety and the hydrolysate accumulation. The rank order of the susceptibility rates of the cleavage reactions was Ser > Pro, Gly > Arg, Ala, Glu, Thr, Asp > His, Lys > Trp, Tyr, Ile, and that of the ring-opening reaction was Ile > Tyr, Trp > Arg, His, Lys, Asp > Glu > Ala > Pro, Gly > Ser > Thr. The rank order of the half-lives of the model peptides was Pro > Arg, Lys, Ile > His, Glu > Ala, Tyr > Asp > Gly > Ser > Thr. The results indicated that a bulky and sterically hindered side chain of the amino acid residue neighboring the pGlu moiety favors the ring-opening reaction, and retards the decomposition on acid hydrolysis and the cleavage reaction. Thus, the ring-opening and the cleavage reactions were greatly affected by the amino acid residue neighboring the pGlu moiety in the hydrolysis of pGlu-peptides.
Dog neuromedin U-8 (d-NMU-8; pGlu-X2-Leu-Y4-Arg-Pro-Arg-Asn-NH2, X = Y = Phe) has potent biological activity to stimulate an isolated chicken crop smooth muscle preparation with the relative activity (RA value) of 5.78 to porcine neuromedin U-8 (p-NMU-8). To elucidate the contribution of the two phenylalanine residues of NMU-8 to the biological activity, fourteen d-NMU-8 analogs modified either at position 2 or 4, [X2]- or [Y4]-d-NMU-8, were synthesized, where X and Y were Ala, Tyr, Trp, Thr, Glu, His or cyclohexylalanine (Cha). Most of the analogs retained very low contractile activity, suggesting the importance of both Phe residues in d-NMU-8 for the biological activity. [X2]-d-NMU-8 analogs had lower biological activity in terms of the RA value than the corresponding [Y4]-d-NMU-8, when X and Y are the same amino acid. Loss of aromaticity of Phe2 ([Cha2]-d-NMU-8) resulted in a marked decrease of the contractile activity, while that of Phe4 ([Cha4]-d-NMU-8) resulted in retention of considerable activity, with the RA value of 2.68. [Tyr4]-d-NMU-8 was an exceptional analog with higher contractile activity (p < 0.01) than the parent compound d-NMU-8, having the RA value of 12.6. The results indicated that the aromatic side chain of the Phe residue at position 2 contributes more than that at position 4 to the biological activity.
A method for highly selective cleavage of pGlu-peptide linkages in 70% methanesulfonic acid (MSA) is described. When pGlu-Ala-Phe-OH, pGlu-His-Pro-Oh and dog neuromedin U-8 (d-NMU-8) (1--7)-OH (pGlu-Phe-Leu-Phe-Arg-OH) were hydrolyzed in 70% MSA at 60 degrees C for 3 h or at 25 degrees C for 3 d, the pGlu-peptide linkage was predominantly cleaved to give H-Ala-OH, H-His-Pro-OH and H-Phe-Leu-Phe-Arg-Pro-Arg-OH, in high yields. The results indicated that pGlu-peptide linkages are highly susceptible to 70% MSA, whereas the amide bond of the pyrrolidone moiety of the pGlu residue and other internal peptide bonds are extremely resistant.
Highly selective cleavage reaction of pGlu-peptide bond is described. Two model peptides, pGlu-X-Ala-Phe-OH (X = Ile and Ser), and dog neuromedin U-8 (d-NMU-8) (1-7)-OH (pGlu-Phe-Leu-Phe-Arg-Pro-Arg-OH) were hydrolyzed in concentrated HCl at 0 degree C for from 6 days to 6 weeks to give the predominant cleavage products of pGlu-X linkage of pGlu-X-Ala-Phe-OH and the pGlu-Phe linkage of d-NMU-8 (1-7)-OH, respectively. The ring-opening reaction of the pyrrolidone moiety of the pGlu residue occurred to a considerably lesser extent.
Synthetic dog neuromedin U-25(d-NMU-25), U-8(d-NMU-8) and their fragments wer examined for contractile activity on chicken crop smooth muscle preparation. The relative activities of d-NMU-25, d-NMU-25(15--25)NH2 and d-NMU-8 to porcine neuromedin U-8 (p-NMU-8) were 1.69, 2.54 and 5.78, respectively. High activity of d-NMU-8 may be attributable to the N-terminal pGlu residue, which provides resistance to aminopeptidases. Various NMU-8 analogs, having various amino acids, N alpha-acetylated amino acids, D-amino acids, or simple organic acids at position 1, were synthesized and evaluated for contractile activity. None of the substitutions caused a significant decrease of the biological activity. Modification at the N-terminal to give aminopeptidase resistance produced analogs with increased contractile activity, presumably because they were not degraded by soluble enzymes released into the bioassay fluid from isolated chicken crop tissue.
To develop a highly potent agonist and to examine the structure-contractile activity relationship of neuromedin U-8(NMU-8), seventeen analogs were synthesized and tested for contractile activity on isolated chicken crop smooth muscle preparations. The analogs were designed to examine the contributions of cyclic structure and acidic function at the N-terminal of NMU-8 and NMU-8(2--8) to the biological activity. The relative activity (RA) values of NMU-8 analogs were as follows: [Dp-Glu1]-NMU-8,5.50; [pyrohomoglutamyl(pHgu)1]-NMU-8,4.65;[D-pHgu1]-NMU-8, 4.66; [Asp1]-NMU-8, 11.4; [acetyl(Ac)-Asp1]-NMU-8, 9.81; [Ac-Glu1]- NMU-8, 18.6; [succinyl (Suc)-Tyr1-NMU-8,69.3; [3-sulfoalanyl (Sal)1]-NMU-8, 12.7. The RA values of NMU-8(2--8) analogs were as follows: alpha-picolinyl (Pic)-NMU-8 (2--8), 7.96; 2-furoyl (Fur)-NMU-8, (2--8), 9.91; 2-thiophenecarboxyl (Thi)-NMU-8 (2--8), 3.41; 4-hydroxyphenylpropionyl (Hpp)-NMU-8(2--8), 3.20; o-phthalyl (Pht)-NMU-8 (2--8), 11.3; Suc-NMU-8 (2--8), 109; malonyl (Mlo)-NMU-8 (2--8), 17.9; maleyl (Mle)-NMU-8 (2--8), 31.6; glutaryl (Glt)-NMU-8 (2--8), 81.3; The potencies of the analogs were higher than that of p-NMU-8. Suc-NMU-8 (2--8) showed the highest potency among the analogs synthesized. The results reveal that the carboxylic acid group at the N-terminus of NMU-8 makes a major contribution to the activity.