Standard method for diagnosing dilatation of the renal pelvis and ureter discovered in the fetus, neonate or infant.
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Child↗
Biomedical subjects
Kenji Shimada
Publications and source records attributed to Kenji Shimada.
Effect of ureteral reimplantation on prevention of urinary tract infection and renal growth in infants with primary vesicoureteral reflux.
AIM: We retrospectively reviewed the results of ureteral reimplantation in infants with primary vesicoureteral reflux (VUR) to evaluate the effect on prevention of urinary tract infection (UTI) and renal growth. MATERIALS AND METHODS: From July 1991 to December 2001, a total of 205 infants (180 boys and 25 girls) with primary VUR underwent ureteral reimplantation at the Department of Urology, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan. Indications for surgery were high-grade reflux (grade IV-V), breakthrough UTI and non-compliance of medical treatment. Age at surgery raged from 1 to 11 months (mean, 6.4 months). Ureteral reimplantation was performed according to Cohen's method. Only two of 336 refluxing ureters required ureteral tailoring. Follow-up ranged from 12 to 110 months (mean, 64 months). Surgical outcome, frequency of UTI and individual renal growth measured by (99m)Tc-dimercaptosuccinic acid (DMSA) scintigraphy was evaluated. RESULTS: Postoperative ultrasound and voiding cystourethrography showed neither residual reflux nor ureterovesical obstruction. Contralateral low grade reflux occurred in six of 74 patients (8.1%) who had unilateral reflux preoperatively. After reimplantation, 10 patients documented 13 febrile UTI. Eleven of the 13 episodes occurred early in the postoperative period (<6 months). Frequency of febrile UTI reduced from 0.23538 before surgery to 0.00894 and 0.00081 per patient per month at 6 and 12 months after surgery, respectively. No development of renal scarring was seen in postoperative DMSA scan. Changes of differential renal function was <0.05 in all patients. CONCLUSION: The present results show ureteral reimplantation in infants is safe and very effective for the prevention of UTI. After surgical treatment in infancy, individual renal growth of children with primary VUR is stable.
Female↗
Sweet potato acid phosphatase immobilized on glutaraldehyde-activated aminopropyl controlled-pore glass: activation, repeated use and enzyme fatigue.
Sweet potato acid phosphatase was covalently coupled with glutaraldehyde to aminopropyl controlled-pore glass, and used as a pre-column enzyme reactor. The immobilized enzyme reactor (IMER) was continuously operated using an automated chromatographic detection system we developed. Functional evaluation of the IMER was carried out by injecting ten samples on the same day at an injection amount of 1.25 nmol (62.5 nmol per ml) using riboflavin sodium phosphate (FMNs) as a substrate, and by prolonged use for ten months. The IMER exhibited decreased activity after repeated use for a total of 3000 samples, but about 75% of its original activity remained. The conversion rate of FMNs to riboflavin by IMER was increased from 89 to 97% by adding citrate, ethylenediaminetetraacetic acid disodium salt, etc., but especially by adding citrate. The increased conversion of FMNs to riboflavin due to the addition of citrate was probably not due to the chelation of heavy metal ions by citrate. We also investigated complex formation of acid phosphatase with the substrate FMNs using surface plasmon resonance to determine the effect of citrate on the processes of association and/or dissociation between the enzyme and substrate. Enzyme fatigue was also observed during the course of prolonged and repeated use.
Acid Phosphatase↗
Rapid analysis of 4-O-methylpyridoxine in the serum of patients with Ginkgo biloba seed poisoning by ion-pair high-performance liquid chromatography.
We have established a new method of HPLC analysis for the rapid separation from human serum and the quantification of 4-O-methylpyridoxine (MPN), which is contained in Ginkgo biloba seeds, and which, when consumed in large amounts, causes vomiting and convulsions. As a result of using IPCC-MS3 (GL Science, Tokyo, Japan), an ion-pair reagent, in the mobile phase, we succeeded in separating MPN in the deproteinized serum sample which was introduced directly onto the reverse-phase HPLC column. For the calibration curve of MPN standard solution, prepared with fluorescence detection at an excitation wavelength of 290 nm and an emission wavelength of 400 nm, a good linear relationship was obtained within the HPLC injection range of 10 ng-10 pg (in terms of the injected sample concentration, range: 1.0 microg/ml-1 ng/ml), allowing the detection of minute amounts, with the limit of detection (concentration of injected sample: 500 pg/ml) being 5 pg. In addition, when MPN solution was added to human reference serum to give a concentration of 0.002 microg/ml, the mean recovery rate was 92.5%, with RSD=7.09% (n=5). The time required for one analysis using this method is approximately 30 min, and thus it offers the advantages of greater speed and superior analytical sensitivity over the conventional methods, which require solid-phase extraction. We employed our new method to determine both the serum levels of MPN in 5 patients with Ginkgo biloba seed poisoning and the levels of free-form MPN in such seeds obtained in 8 regions of Japan.
Adult↗
[Differentiation of external genitalia and 5 alpha-reductase].
Sexual differentiation of the external genitalia depends on many factors such as genetic sex, gonadal sex or androgen action. Among them, 5 alpha-reductase plays an important role in androgen action: dihydrotestosterone(DHT) is produce from testosterone by 5 alpha-reductase and DHT binds the androgen receptor to induce the differentiation of the external genitalia. In this paper we reviewed on the mechanism of the differentiation of the external genitalia, especially on the relation with androgen action and 5 alpha-reductase.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
[Decision-making process about sex assignment in the neonate with ambiguous genitalia].
Although diagnoses and etiologies of underlying disorders of sexual differentiation can be carefully delineated through biochemical, imagine, and chromosomal analyses, the decision-making process about sex assignment in the newborn with ambiguous genitalia is in a state of controversy. The conventional way for the approach to these neonates consists of 4 principles; 1) Urgency of diagnosis and sex assignment, so that early surgical reconstruction could obviate the fear of the parents with each diaper change. 2) Adequacy of the phallus as a male. 3) Fertility, especially 46XX female are sex assigned female because of potential fertility. 4) Cosmetic appearance of the reconstructed genitalia based on the recognition that external female genitalia are generally easier to construct than male. Contrary to these conventional methods, some researchers insist on flexibility in the clinical approach to provide the best possible outcome. It is getting apparent that the quantity, timing, and duration of androgen exposure will play a role in determining the degree of masculinization of the brain, which may potentially decide gender identity before 18 months of age or even in utero, and may influence the psychosexual development of the child. Flexibility in decision-making will allow for options not to remove any tissues including gonads and internal sex organs, or to reconstruct the genitalia until he or she is sure of the gender. This new approach must be proved in the future.
Adolescent↗
Specific determination of myo-inositol in multivitamin pharmaceutical preparations by a flow injection system using a myo-inositol dehydrogenase reactor coupled with a glucose eliminating enzyme reactor.
A flow injection system for myo-inositol determination in multivitamin pharmaceutical preparations using two enzyme reactors was developed. Myo-inositol was detected using a fluorophotometer, to measure the fluorescence of NADH produced from NAD+ by a myo-inositol dehydrogenase reactor (IDR) containing myo-inositol dehydrogenase immobilized on porous glass. Enhanced interference due to excess glucose included in a multivitamin pharmaceutical preparation as a sweetener was eliminated by a glucose eliminating reactor (GER) co-immobilized with three enzymes (glucose oxidase, mutarotase and catalase). The calibration coefficient for the standard curve was 0.9993 for myo-inositol detection in the range of 1-5 microg/ml. Myo-inositol was determined even in the presence of glucose concentrations of 140-420 microg/ml. The recovery of myo-inositol added to the multivitamin pharmaceutical preparation was 99.6% (n=9).
Enzyme Reactivators↗
DNA polymerase stabilization at stalled replication forks requires Mec1 and the RecQ helicase Sgs1.
To ensure proper replication and segregation of the genome, eukaryotic cells have evolved surveillance systems that monitor and react to impaired replication fork progression. In budding yeast, the intra-S phase checkpoint responds to stalled replication forks by downregulating late-firing origins, preventing spindle elongation and allowing efficient resumption of DNA synthesis after recovery from stress. Mutations in this pathway lead to high levels of genomic instability, particularly in the presence of DNA damage. Here we demonstrate by chromatin immunoprecipitation that when yeast replication forks stall due to hydroxyurea (HU) treatment, DNA polymerases alpha and epsilon are stabilized for 40-60 min. This requires the activities of Sgs1, a member of the RecQ family of DNA helicases, and the ATM-related kinase Mec1, but not Rad53 activation. A model is proposed whereby Sgs1 helicase resolves aberrantly paired structures at stalled forks to maintain single-stranded DNA that allows RP-A and Mec1 to promote DNA polymerase association.
DNA Helicases↗
Fairly marked enantioselectivity for the hydrolysis of amino acid esters by chemically modified enzymes.
The hydrolysis (deacylation) of enantiomeric substrates by the chemically modified enzymes decanoyl-alpha-chymotrypsin and decanoyl-trypsin was studied. Reaction activity for decanoyl-alpha-chymotrypsin was lower than that for the native enzyme, although intriguingly the enantioselectivity was markedly enhanced as compared with the native enzyme. In particular, the apparently complete enantioselective catalysis was attained for the hydrolytic cleavage of p-nitrophenyl N-dodecanoyl-D(L)-phenylalaninates. The enhancement of enantioselectivity, however, was not observed for decanoyl-trypsin. These results suggest that the chemically modified alpha-chymotrypsin by addition of hydrophobic groups has promoted enantioselectivity for the hydrolysis of hydrophobic esters.
Algorithms↗
Analysis of acetaminophen glucuronide conjugate accompanied by adduct ion production by liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry.
Liquid chromatography-mass spectrometry (LC-MS) is an effective method for the analysis of polar compounds. A coupling of LC-MS, which is used under conventional conditions, and atmospheric-pressure chemical ionization (APCI), which applies mild ionization for the analysis of water-soluble drug conjugates, would offer a very convenient method. The APCI method is effective for ionizing low- and medium-polarized compounds, but not for highly polarized compounds. In this study, we have tried derivatization of carboxyl group of glucuronic acid, to which direct ionization is difficult to apply under the APCI method, was conducted using glucuronides. Methyl ester derivatives were found to be effectively ionized. Furthermore, acetaminophen glucuronide conjugate was investigated in detail. Methyl ester derivatives of acetaminophen glucuronide conjugate (ACEG) were detected at m/z 373 as O(2) adduct ion [M+O(2)](-) in the negative mode, and p-nitrophenyl beta-D-glucuronide (PNPG) demonstrated ionization behaviors very similar to ACEG. Quantitation of ACEG was examined using PNPG as an internal standard, and satisfactory results were obtained for the recovery test and quantification.
Acetaminophen↗
Clinical characteristics of primary vesicoureteral reflux in infants: multicenter retrospective study in Japan.
PURPOSE: We evaluate clinical characteristics of primary vesicoureteral reflux in infants in a multicenter study in Japan with special reference to the relation of renal parenchymal damage to urinary tract infection and gender. MATERIALS AND METHODS: Infants younger than 1 year old with primary vesicoureteral reflux were recruited from 14 hospitals during the 3-year registration period beginning in January 1996 and ending in December 1998. Various clinical parameters as well as renal parenchymal lesion on dimercaptosuccinic acid scintigraphy were evaluated. RESULTS: Of 356 infants enrolled 296 (83%) were male and 60 (17%) were female. In 85% of infants presenting symptom was febrile urinary tract infection. There were 204 bilateral (57%) and 152 unilateral (43%) cases. Reflux was bilateral in 56% of males versus 65% of females, and high grade (grades IV and V) in 58% of males versus 55% of females. Diffuse parenchymal lesion was similarly noted in infants with or without prior urinary tract infection (38% and 46%, respectively) and was more often noted in male than in female infants (42% versus 25%). CONCLUSIONS: Despite the current use of screening prenatal ultrasound, many infants are still diagnosed as having vesicoureteral reflux only after the occurrence of urinary tract infection. The greater severity of renal parenchymal lesion in male infants combined with similar incidence of diffuse parenchymal lesion in those with or without prior infection suggests preexisting congenital abnormalities in the male refluxing kidney.
Female↗
Histological study of fetal kidney with urethral obstruction and vesicoureteral reflux: a consideration on the etiology of congenital reflux nephropathy.
PURPOSE: A recent subject of interest regarding reflux nephropathy is the presence of renal abnormalities in neonates and infants who have no history of urinary tract infections. Debates have centered on the etiology of this renal abnormality - congenital reflux nephropathy; regarding whether it is the result of abnormal ureteral budding or of back pressure effect from sterile reflux. We examined the renal pathology of fetuses with urethral obstruction and vesicoureteral reflux, and we suggest herein a possible etiology of congenital reflux nephropathy. METHODS: The renal pathology of seven autopsied fetuses with vesicoureteral reflux was studied. Reflux was demonstrated at autopsy by slow injection of contrast medium into the bladder. Severe urethral obstruction, either atresia or urethral valves, was evident in six of the subjects. RESULTS: In six subjects, abnormality of the urinary tracts was detected by prenatal ultrasonography. Of these six subjects, three revealed characteristics of prune belly syndrome. Reflux was graded as moderate in five subjects, and severe in two. In three subjects autopsied at 21 weeks gestation or earlier, the kidneys were well-developed with normal corticomedullary configuration, and nephrogenesis was retained. In three cases autopsied at over 25 weeks of gestation, the kidneys were grossly cystic, and the nephrogenic zone was completely absent. Contrast medium was observed not only in the dilated ducts and tubules, but also in the subcapsular cysts. Extravasation of the contrast medium was seen in the peritubular space. In the last subject with normal lower urinary tract, abnormal segments among normal cortical structures were observed. CONCLUSION: Our findings of renal pathology in fetuses with reflux are quite similar to those seen in fetal hydronephrosis. Back pressure from reflux probably damages the developing kidney leading to a degeneration of the ampullae and a reduction in the number of nephrons. Both dilatation of the collecting ducts and tubules, and extravasation of the urine may result in interstitial fibrosis. We postulate that one of the important etiologies of congenital reflux nephropathy may be the result of back pressure from sterile reflux.
Cadaver↗
Determination of the herbicide glyphosate and its metabolite in biological specimens by gas chromatography-mass spectrometry. A case of poisoning by roundup herbicide.
In Japan, poisonings by the glyphosate (GLYP)-containing herbicide Roundup and the gluphosinate (GLUF)-based herbicide BASTA have been increasing since about 1987. We applied the gas chromatography-mass spectrometry (GC-MS) method of analysis, on which we have already reported in regard to the determination of the blood serum level of GLUF and its metabolite, for the determination of serum and urinary levels of GLYP and its metabolite aminomethyl phosphonic acid (AMPA). Derivatization using N-methyl-N-(tert-butyldimethylsilyl) trifluoroacetamide was completed at a temperature of 80 degrees C after 30 min, and the detection limit of GLYP was 10 pg using m/z 454 and that of AMPA was 1 pg using m/z 396. The full mass spectra of 100 pg GLYP and of 10 pg AMPA were obtained easily. In extractions for which the Isolute HAX cartridge was employed, the mean recovery rate of GLYP and AMPA added to serum to yield concentrations of 10-0.1 microg/mL (n = 5) was 91.6 +/- 10.6% (or better), whereas that of GLYP and AMPA added to urine to yield concentrations of 100-1.0 microg/mL (n = 10) was 93.3 +/- 6.6% (or better), both of which were good rates. Also, using this method of analysis, the presence of GLYP was identified in the full mass spectra obtained from the serum of a patient who may or may not have ingested Roundup.
Aminobutyrates↗
High performance liquid chromatographic determination of acetoacetate by post-column derivatization with p-nitrobenzene diazonium fluoroborate.
We have applied a color-developing reagent, p-nitrobenzene diazonium fluoroborate (diazo reagent) as a post-column derivatization tool for the specific determination of acetoacetate (AcAc) in high performance liquid chromatography (HPLC). A mobile phase consisting of 50 mM KH(2)PO(4), 4 mM tetra-n-butylammonium phosphate (TBAP) as an ion-pair reagent and 2 v/v% methanol, pH 3.5, diazo reagent solution with 0.2% triton X-100, and alkaline solution of 1.5 mol/l NaOH were pumped using three independent pumps. Specific color development on-line was monitored at 645 nm. A calibration curve for AcAc standard solution with an injection volume of 20 microl showed a good linearity in the range 0.01-2.5 mM with a correlation coefficient of 0.999. For the determination of 3-hydroxybutyrate (3-HOBA), 3-HOBA was converted to AcAc by an enzymatic-coupling method using 3-HOBA dehydrogenase and lactate dehydrogenase. Analytical recoveries of AcAc and 3-HOBA added to serum and urine were satisfactory.
Acetoacetates↗
Toxicokinetics of DL-glufosinate enantiomer in human BASTA poisoning.
We found that glufosinate (DL-GLUF) was distributed in the spinal fluid in glufosinate poisoning. A 50-year old Japanese man (weighing 67 kg) attempted to commit suicide by ingesting about 100 ml of BASTA (containing DL-GLUF 18.5 g; ratio of D-GLUF to L-GLUF: 1 : 1). He was transported to our hospital, where serious respiratory depression was seen 26 h after ingestion, and management with artificial ventilation was initiated. The D-GLUF concentration 1 h after ingestion was 191.1 microg/ml, almost the same as that of L-GLUF 193.5 microg/ml, but by 3 h after ingestion, these levels had sunk to 60.3 microg/ml and 52.3 microg/ml, respectively, with the concentration of L-GLUF lower than that of D-GLUF. Later, at 27 and 35 h after ingestion, the D-GLUF level was still higher than the L-GLUF level, and the total amounts of urinary excretion were 2835 mg for D-GLUF and 2298 mg for L-GLUF, each variable thus showing a difference between the enantiomers. Cerebrospinal fluid taken from the patient 27 h after poison ingestion revealed the presence of DL-GLUF on CG-MS analysis, and quantitative HPLC analysis of the enantiomers indicated that the D-GLUF concentration was 0.48 microg/ml, and the L-GLUF concentration 0.12 microg/ml. The levels in blood collected at the same time were: D-GLUF, 1.44 microg/ml, and L-GLUF, 0.35 microg/ml. Also, the cerebrospinal fluid contained about one-third of the blood levels of both DL-GLUF enantiomers. He was discharged without any sequelae after 11 d of hospitalization.
Aminobutyrates↗
Determination of selenium in human serum by liquid chromatography/electron capture atmospheric pressure chemical ionization mass spectrometry after acid digestion and derivatization using 2,3-diaminonaphthalene.
Analysis of selenium in biological samples is very important and numerous analytical methods for the element have been developed. One of the most convenient and widely used methods for routine determination of serum selenium is a fluorometric method using 2,3-diaminonaphthalene (DAN); however, this method lacks specificity. We observed that 4,5-benzopiazselenol (BPS), a selenium derivative of DAN, is ionized with electron capture in an atmospheric pressure chemical ionization (APCI) interface, and subsequently established a method for determining total human serum selenium by means of liquid chromatography/atmospheric pressure chemical ionization mass spectrometry. All pretreatment procedures were carried out in a single test tube to minimize selenium loss. The recovery of organic or inorganic selenium spiked to human serum was 97-103%. The detection limit of BPS was equivalent to 0.2 ng of selenium and the lower quantitative limit of serum selenium was 10 ng mL(-1). The coefficient of variation of standard concentrations in control serum samples was 4.5%. The purity of the observed peak obtained from serum samples was confirmed using the ion cluster technique.
2-Naphthylamine↗
Assessment of tear concentrations on therapeutic drug monitoring. III. Determination of theophylline in tears by gas chromatography/mass spectrometry with electron ionization mode.
A simple and sensitive method for the quantitation of theophylline (TP) in tears and plasma developed using gas chromatography/electron-impact ionization/mass spectrometry. Tears were collected by non-invasive Schirmer method. Plasma was pipetted on a Schirmer tear test strip (cutting to 5 mm x 5 mm). Then, TP was converted directly into its pentafluorobenzoyl amide derivative without the need to perform any extraction from the biological fluid absorbed on Schiemer test paper and was quantified by gas chromatography-selected ion recordings with electron ionization mode. The concentrations in tears [C]t correlated very well with those of the free form in the plasma [Cf]p and those of the total form in the plasma [Cb+f]p. The ratios between TP concentrations in tears and plasma (free and total form) were as follows: [C]t/[Cb+f]p=0.53+/-0.20; [C]t/[Cf]p=1.21+/-0.19; [Cf]p/[Cb+f]p=0.44+/-0.14. The ratios of [C]t/[Cb+f]p, [C]t/[Cf]p and [Cf]p/[Cb+f]p were in good agreement with the previously published data.
Journal Article↗
ORC and the intra-S-phase checkpoint: a threshold regulates Rad53p activation in S phase.
The intra-S-phase checkpoint in yeast responds to stalled replication forks by activating the ATM-like kinase Mec1 and the CHK2-related kinase Rad53, which in turn inhibit spindle elongation and late origin firing and lead to a stabilization of DNA polymerases at arrested forks. A mutation that destabilizes the second subunit of the Origin Recognition Complex, orc2-1, reduces the number of functional replication forks by 30% and severely compromises the activation of Rad53 by replication stress or DNA damage in S phase. We show that the restoration of the checkpoint response correlates in a dose-dependent manner with the restoration of pre-replication complex formation in G1. Other forms of DNA damage can compensate for the reduced level of fork-dependent signal in the orc2-1 mutant, yet even in wild-type cells, the amount of damage required for Rad53 activation is higher in S phase than in G2. Our data suggest the existence of an S-phase-specific threshold that may be necessary to allow cells to tolerate damage-like DNA structures present at normal replication forks.
Cell Cycle Proteins↗