Steroids excreted in urine by neonates with 21-hydroxylase deficiency: Characterization, using GC-MS and GC-MS/MS, of the D-ring and side chain structure of pregnanes and pregnenes

Steroid metabolites in urine from neonates with 21-hydroxylase deficiency are predominantly polyhydroxylated 17-hydroxyprogesterone and androgen metabolites, and most have incompletely defined structure. This study forms part of a comprehensive project to characterize and identify these in order to enhance diagnosis and to further elucidate neonatal types of steroid metabolism.Steroids were analyzed, after extraction and enzymatic conjugate hydrolysis, as methyloxime-trimethylsilyl ether derivatives on gas-chromatographs coupled to quadrupole and ion-trap mass-spectrometers. GC-MS and GC-MS/MS spectra, obtained with constant excitation conditions, were used together to determine the structure of the D-ring and the side chain of 20-oxo and 20-hydroxy pregnane(ene)s without oxo groups on the A-, B-, and C-ring.All possible combinations of D-ring and side chain configuration were considered. Most fragmentations could be interpreted as partial or complete D-ring cleavages with loss of the side chain, aided by comparison with spectra of deuterated derivatives and of borohydride reduced metabolites. Possible rearrangement ions are also discussed. More than 140 endogenous metabolites were characterized.GC-MS/MS was especially beneficial for characterization of compounds with 16,17-dihydroxy-20-oxo structure, interpreted as markers of intra-uterine enzyme induction. It also assisted the differentiation of 16-hydroxy-20-oxo metabolites, present in urine of non-affected neonates, from the diagnostic 17-hydroxy-20-oxosteroids and enabled the detection of 15,17-dihydroxy-20-oxo compounds in low concentrations. The presence of 17,21-dihydroxylated pregnane(ene)s despite the deficit in CYP21A2 is discussed.We conclude that GC-MS combined with GC-MS/MS allows reliable identification of the structure of the D-ring and side chain of pregnane(ene)s without prior isolation, even when in low concentrations in urine.     

Long term urinary platinum, palladium, and gold excretion of patients after insertion of noble metal dental alloys

The aim of this study was to investigate to which extent noble-metal dental alloys contribute to the total platinum (Pt), palladium (Pd), and gold (Au) body burden of the general population. The urinary Pt, Pd, and Au excretion was determined in three non-occupationally exposed volunteers before and up to 3 months after insertion of a highgold dentalalloy. The in-vitro release of Pt, Pd, and Au from four different types of dental alloys into either artificial saliva or 1% lactic acid solution was additionally investigated. The Pt, Pd, and Au concentrations were determined by sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). Before insertion of the high-gold dental alloy, the Pt excretion of the patients ranged between 1.0 and 7.4 ng l-1 (0.6-3.3 ng g-1 creatinine). In the immediate post-insertion phase the Pt excretion rose to 10.5-59.6 ng l-1 (14.5-33.2 ng g-1 creatinine). This is a mean increase by a factor of 12 compared with the average Pt excretion before insertion. Three months after insertion, the Pt excretion was still elevated by a factor of 7. Contrary to Pt, the Au and Pd excretion in urine was not significantly increased after insertion of this type of high-gold dental alloy. Our in-vitro investigations confirm the assumption that Pt, Pd, and Au are released from noble metal containing dental alloys by corrosion. Under the applied conditions, the release was in the lower ng cm-2 range. It can be concluded that the Pt release from dental alloys can predominantly contribute to the Pt exposure of non-occupationally exposed persons. It can exceed the exposure from all other environmental sources including the Pt release from automobile exhaust catalysts.     

Water-soluble glucans from the seed of Coix lacryma-jobi var. ma-yuen

The water-soluble major polysaccharides from the seed of Coix lacryma-jobi var. ma-yuen eluted as a broad peak by gel filtration on Sepharose CL-2B. The mixture (CS-Glucan) was resolved into 7 glucans by HPLC on the column of Asahi-Pak GS-510 + GS-320. Similarities were observed between M, shown in the gel filtration profile and the elution volume in HPLC. Methylation analysis indicated that the ethanol-fractionated CS-glucan contained 4-O- and 4,6-di-O-substituted glucosyl residues. ¹H and ¹³C NMR data accorded with the results of methylation analysis, and the glycosidic linkages were shown to have an α-configuration. Thus, CS-glucan contained (1 → 4) linked α-d-glucans to which are attached glucosyl side chains at O-6 of the main chain in a similar way to amylopectin. Each purified glucan was shown to have different absorption maxima ( > 550 nm or 530 nm) in the iodine reaction. The results of the methylation analysis and of the pullulanase digestion suggest that the 550 nm-glucan has a lower branching frequency and shorter side chains than the 530 nm-glucan. Although CS-glucan was found to have weak anti-complementary activity, HPLC-purified > 550 nm-glucan was found to be more potent than the 530 nm-glucan. Thus CS-glucan is highly heterogeneous, and the glucans which form a tight complex when tested with iodine, generally tend to have considerable anti-complementary activity.     

Effects of anions, acetazolamide, thiocyanate and amiloride on fluid secretion by the Malpighian tubules of Locusta migratoria L.

The effect of Cl⁻, HCO₃⁻, Br⁻, acetazolamide, thiocyanate and amiloride on urine formation in Locusta migratoria Malpighian tubules have been determined. The rate of fluid secretion depends markedly on the concentration of Cl⁻ in the bathing solution with concentrations less than 90 mM resulting in reduced fluid secretion. Substitution of Br⁻ for Cl⁻ had no significant effect on the rate of the fluid secretion. Replacement of NaHCO₃ with NaCl in Hepes buffered Ringer solution reduced the rate of urine production by 23%. Fluid secretions were reduced in the presence of 10⁻⁴–10⁻² M acetazolamide, a carbonic anhydrase inhibitor. The combined effect of acetazolamide in the absence of HCO₃⁻ appears to be additive. A 1 mM concentration of thiocyanate, an ionic inhibitor, reduced fluid secretion by 35%. Amiloride interferes with the electrogenic entry of Na⁺ into the cell and a 1 mM solution reduced fluid secretion by 94% with secretion completely inhibited in 80% of the tubules tested.     

D-Amino acids in chronic renal failure and the effects of dialysis and urinary losses

Summary Total D-amino acids were measured in plasma for 20 non-dialysed patients (creatinine clearance < 12 ml/minute), 20 on CAPD, 20 on haemodialysis and 20 normals. Plasma D-tyrosine and D-phenylalanine were measured in 8 of each group by HPLC. Total D-amino acids, D-tyrosine and D-phenylalanine were significantly greater for patients than normals. D-amino acids and D-tyrosine correlated with creatinine and were decreased during HD. During dialysis, the mean losses for D-tyrosine and D-phenylalanine were similar, about 0.2 mg/CAPD exchange and 3 mg/4 hour haemodialysis (i.e. 2% of the total amino acid, as in plasma). Clearance was unaffected by stereochemical configuration. Urinary losses/24 hour in the non-dialysed patients were 0.35 mg D-tyrosine and 0.25 mg D-phenylalanine. Clearance for D-phenylalanine was greater than for the L-enantiomer. Increases in D-amino acids in renal failure are probably due to depletion of D-amino acid oxidase, but may be enhanced by a D-amino acid rich diet, peptide antibiotics and D-amino acid oxidase inhibiting drugs and metabolites. Possible toxic effects need further investigation.     

人巨细胞病毒的生物素DNA探针的制备和应用

本研究用克隆的HCMV AD169株DNA片段,制备了生物素标记的DNA探针,建立了检测临床脐带血、尿标本中HCMV DNA的核酸探针杂交方法。该探针可测出100pg同源DNA,不与人胚肺细胞、Hep-2细胞DNA以及其他疱疹病毒的DNA发生反应。用核酸杂交方法检测了30份脐带血标本,有11例阳性,阳性率为33％。10例孕妇尿标本中,3例阳性,阳性率为30％。检测结果表明：我们建立的生物素标记的HCMV DNA探针的点杂交法,具有高度的特异性、敏感性,比分离病毒法更迅速,可用于HCMV感染的临床标本的病毒核酸检测。     

Human urinary and blood toxicokinetics of beryllium after accidental exposure

PurposeBeryllium is known to have adverse health effects and is classified as carcinogenic to humans. However, data on systemic beryllium exposure in humans are rare and especially human toxicokinetics are largely uncharted. As such, the first reported multi-annual course of blood and urine concentrations after a high exposure scenario provides important new insights.MethodsFor a medical follow-up biomonitoring samples were collected for 56 months from a male subject after an accidental and multi-faceted high exposure. Sampling started on day 2 post-exposure for urine and day 147 for blood. The samples were analyzed by inductively coupled mass spectrometry (ICP-MS) and plotted longitudinally as a function of time. Terminal half-lives were calculated assuming a first-order elimination process.Main findingsBoth matrices showed highly increased initial concentrations (about 100-fold), despite the 147-day delay in blood sampling, and a marked decline over time. In urine, a two-phase excretion process was suspected based on the longitudinal data. Calculations gave terminal half-lives of 117.5 days and 666.5 days for phases 1 and 2, respectively. Blood kinetics called for a terminal half-life of 103.5 days. Elimination kinetics in blood and urine were comparable, simultaneously gathered samples showed an excellent correlation (R² = 0.985).Principal conclusionsThe long-term follow-up after a high initial exposure to beryllium provides the first detailed insights into the elimination course of systemically available beryllium in humans. Conform kinetics of beryllium in urine and blood and the strong correlation between both parameters indicate high data validity and support the good representation of the current systemically available beryllium by urine and blood concentration in humans. The relatively long terminal half-lives in both matrices suggest a possible accumulation in humans in case of repeated exposures.     

Relationship between mild iodine deficiency in pregnant women and thyroid function: A meta-analysis

BackgroundPregnant women are among the key groups in iodine nutrition evaluation. The purpose of the present study was to summarize the evidence supporting the relationship between mild iodine deficiency (UIC: 100–150 μg/L) in pregnant women and levels of thyroid function tests.MethodsThis review follows the guidelines for systematic reviews (PRISMA 2020). Three electronic databases (PubMed, Medline, and Embase) were searched for relevant publications in English on the association between mild iodine deficiency in pregnant women and thyroid function. Articles published in Chinese were searched in China’s electronic databases (CNKI, WanFang, CBM, and WeiPu). Pooled effects were presented as standardized mean differences (SMDs) and odds ratios (ORs) with 95% confidence intervals (CIs) using fixed or random effect models, respectively. This meta-analysis was registered at www.crd.york.ac.uk/prospero as CRD42019128120.ResultsWe summarized the results from 7 articles with 8261 participants. The overall pooled results showed that the levels of FT₃, FT4, and abnormal TgAb (the antibody levels exceeded the upper limit of the reference range) were significantly increased in pregnant women with mild iodine deficiency compared to pregnant women with adequate iodine status (FT₃: SMD=0.854, 95% CI: 0.188, 1.520; FT₄: SMD=0.550, 95% CI: 0.050, 1.051; TgAb: OR=1.292, 95% CI: 1.095; 1.524). Subgroup analysis was carried out on the sample size, ethnicity, country, and gestation of FT₃, FT_4, and TSH, but no plausible factor was found. Egger’s tests indicated no publication bias.The increase in FT₃ and FT_4, as well as TgAb levels, in pregnant women is associated with mild iodine deficiency.ConclusionMild iodine deficiency is associated with an increase in FT_3,FT₄ and TgAb levels in pregnant women. Mild iodine deficiency may increase the risk of thyroid dysfunction in pregnant women.     

Kidney structure and function of obligate and facultative hibernators: the white-tailed prairie dog (Cynomys leucurus) and the black-tailed prairie dog (Cynomys ludovicianus)

The white-tailed prairie dog is an obligate hibernator that enters a heterothermic phase when maintained in the cold with low intensity light and ad libitum food and water. The black-tailed prairie dog (a facultative hibernator) will not hibernate under similar conditions. It has been suggested that the black tailed prairie dog remains active during the winter because it can conserve water more effectively due to a more efficient kidney. The present study revealed no significant differences between the species in renal morphology: relative medullary thickness, nephron heterogeneity, renal vasculature, or fornix dimensions, all of which are structures associated with the urinary concentrating mechanism. In addition, there was no difference in number of nephrons between the two species. The black-tailed prairie dog does produce a more concentrated urine when food and water deprived. However, this difference was not observed when the animals were salt loaded. The water-deprivation and salt-loading experiments suggest that the higher urine osmolality produced by the back-tailed prairie dog during fasting is a result of a higher urea load due to a greater protein catabolism and not because of a differential capacity to concentrate urine.Abbreviations C cortex - GFR glomerular filtration rate - H height - IS inner stripe - IZ inner zone of medulla - L length - OS outer stripe - PE polythylene - RMT relative medullary thickness - T _a ambient temperature - W width     

Origin ofd-serine present in urine of mutant mice lackingd-amino-acid oxidase activity

Summary Urine of ddY/DAO mice lackingd-amino-acid oxidase contained 5.7 times more serine than that of normal ddY/DAO⁺ mice. Most of the serine wasd-isomer. The origin of this^d-serine was examined. Oral administration of 0.02% amoxicillin and 0.004% minocycline to the ddY/ DAO^- mice for 7 days did not reduce the urinaryd-serine, indicating that thed-serine was not of intestinal bacterial origin. When the mouse diet was changed to one with different compositions, the urinaryd-serine was considerably reduced. Furthermore, starvation of the ddY/DAO^- mice for 24 hours reduced the urinaryd-serine to 33% of the original level. These results indicate that most of the urinaryd-serine comes from the diet. However, the urine of the starved ddY/DAO^- mice still contained 4.6 times mored-serine than that of the ddY/DAO⁺ mice, suggesting a part of the D-serine have an endogenous origin.