Hearing Loss and Urinary trans,trans-Muconic Acid (t,t-MA) in 6- to 19-Year-Old Participants of NHANES 2017-March 2020.

Hearing loss (HL) is associated with poorer language development and school performance. Ototoxic substances such as metals and solvents, including benzene, are a risk factor associated with HL. This study examines potential associations between the benzene metabolite trans,trans-muconic acid (t,t-MA) and HL in youth of the National Health and Nutrition Examination Survey (NHANES). Logistic regression calculated adjusted odds ratio (aOR) associations between HL and urinary t,t-MA quartiles, natural-log transformed, and doubled urinary t,t-MA. Hearing threshold pure-tone average (PTA) at speech frequencies (SF) 0.5, 1, 2, and 4 kHz and high frequencies (HF) 3, 4, and 6 kHz were analyzed for slight HL (PTA > 15 dB) and mild HL (PTA > 20 dB). Urinary t,t-MA was statistically significantly associated with both slight SF and HF HL. For each doubling of t,t-MA there were increased odds of having slight SFHL (aOR = 1.42; 95% CI: 1.05, 1.92), slight HFHL (aOR = 1.31; 95% CI: 1.03, 1.66), mild SFHL (aOR = 1.60; 95% CI: 1.10, 2.32), and mild HFHL (aOR = 1.45; 95% CI: 1.03, 2.04). To our knowledge, this is the first population-based report of an association between SFHL, HFHL, and the benzene metabolite t,t-MA in youth 6 to 19 years old.

The costs incurred by the NHS in England due to the unnecessary prescribing of dependency-forming medications.

This cross-sectional study estimates the costs incurred by the National Health Service (NHS) in England as a consequence of the unnecessary prescribing (i.e. non-indicated or dispensable) of dependency-forming medicines (antidepressants, opioids, gabapentinoids, benzodiazepines, Z-drugs). It assesses prescribing in primary care from April 2015-March 2018. Analyses were based upon the following data sets: the number of adults continuously prescribed dependency forming medications and the duration of prescriptions (obtained from Public Health England); the Net Ingredient Cost (NIC) and the dispensing costs for each medicine (obtained from the NHS Business Service Authority [NHSBSA]). Consultation costs were calculated based on guideline recommendations and the number of consultations evidenced in prior research for long-term medication monitoring. Across opioids, gabapentinoids, benzodiazepines, Z-drugs the total estimated unnecessary cost over three years (April 2015-March 2018) was £1,367,661,104 to £1,555,234,627. For antidepressants the total estimated unnecessary cost for one year was £37,321,783 to £45,765,504. The data indicate that the NHS in England may incur a significant estimated mean annual loss of £455,887,035 to £518,411,542 for opioids, gabapentinoids, benzodiazepines, Z-drugs and an estimated annual loss of £37,321,783 to £45,765,504 for antidepressants. Combined, this gives an estimated annual loss of £493,208,818 to £564,177,046 as a result of non-indicated or dispensable prescribing of dependency-forming medicines. Estimates are conservative and figures could be higher.

Sustaining global partnerships for simulation integration: lessons from the field.

AIM: A reciprocal partnership between two World Health Organization Collaborating Centers in the Americas region aimed to strengthen nursing and midwifery education through innovative integration of high-fidelity simulation. METHODS/IMPLEMENTATION: Immersion of a visiting scholar in six-week training within a North American nursing school (host) solidified simulation champion designation, upon return at the home institution. Next, two expert nursing faculty implemented a train-the-trainer simulation course on-site. Following evaluation and virtual debriefing, a midwifery faculty visited the host institution for second-round training. CONCLUSION: This ongoing program targets faculty development needs through a strong academic partnership, built upon global awareness and sustainable engagement.

Continuous dental eruption identifies Sts 5 as the developmentally oldest fossil hominin and informs the taxonomy of Australopithecus africanus.

The relatively small Australopithecus africanus specimen Sts 5 has figured prominently in taxonomic debates, and the determination of this specimen as a young male or an elderly female has the potential to offer a great deal of resolution on this question. Sts 5 has been argued to be either a small, immature male or a mature female based on a variety of characters. A proposed model of continuous root remodeling and angular change for heavily worn dentition may account for the extremely short tooth roots, particularly for the anterior dentition, that Sts 5 demonstrates. The anterior tooth roots of Sts 5 are oriented vertically (relative to the alveolar plane), unlike those found in most other apes, humans, and fossil specimens, in which the tooth roots are roughly parallel with the plane of the nasoalveolar clivus. Computed tomography (CT) data of adult apes were examined and a relationship between the angle of the anterior tooth roots and their length was discovered, caused by heavily worn anterior dentition continuing to erupt to maintain occlusion. The extremely short and vertically oriented anterior roots observed in Sts 5 thus suggest that the specimen represents an aged female specimen with extremely worn dentition. Interestingly, this reorientation of anterior tooth roots helps account for the unusual nasoalveolar contour of Sts 5. The remodeling associated with the heavily worn teeth and reoriented roots thus resolves the taxonomic question raised by analyses identifying unusual prognathism of this small specimen.

Debromination of polybrominated diphenyl ether-99 (BDE-99) in carp (Cyprinus carpio) microflora and microsomes.

Based on previous findings in dietary studies with carp (Cyprinus carpio), we investigated the mechanism of 2,2',4,4',5-pentabromodiphenyl ether (BDE-99) debromination to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) using liver and intestinal components. In vitro aerobic and anaerobic experiments tested the ability of carp intestinal microflora to debrominate BDE-99. No debromination of BDE-99 to BDE-47 was observed in microfloral samples; therefore, carp enzymatic pathways were assessed for debromination ability. After sixty-min incubation, intestine and liver microsomes exhibited 83+/-34% and 106+/-18% conversions, respectively, of BDE-99 to BDE-47; with no significant (p>0.05) difference between organ debromination capabilities. Microsomal incubations with BDE-99, enzyme cofactors and competing substrates assessed the potential mechanisms of debromination. The presence of NADPH in the microsomal assay did not significantly (p>0.05) affect BDE-99 debromination, which suggest that cytochrome P450 enzymes are not the main debrominating pathway for BDE-99. Co-incubation of BDE-99 spiked microsomes with reverse thyronine (rT3) significantly (p<0.05) decreased the debromination capacity of intestinal microsomes indicating the potential of catalytic mediation via thyroid hormone deiodinases. The significant findings of this study are that intestinal microflora are not responsible for BDE-99 debromination, however, it is an endogenous process which occurs with approximately equal activity in intestine and liver microsomes and it can be inhibited by rT3.

Copper stabilizes a heterodimer of the yCCS metallochaperone and its target superoxide dismutase.

The copper chaperone for superoxide dismutase (CCS) activates the antioxidant enzyme Cu,Zn-SOD (SOD1) by directly inserting the copper cofactor into the apo form of SOD1. Neither the mechanism of protein-protein recognition nor of metal transfer is clear. The metal transfer step has been proposed to occur within a transient copper donor/acceptor complex that is either a heterodimer or heterotetramer (i.e. a dimer of dimers). To determine the nature of this intermediate, we generated a mutant form of SOD1 by replacing a copper binding residue His-48 with phenylalanine. This protein cannot accept copper from CCS but does form a stable complex with apo- and Cu-CCS, as observed by immunoprecipitation and native gel electrophoresis. Fluorescence anisotropy measurements corroborate the formation of this species and further indicate that copper enhances the stability of the dimer by an order of magnitude. The copper form of the heterodimer was isolated by gel filtration chromatography and contains one copper and one zinc atom per heterodimer. These results support a mechanism for copper transfer in which CCS and SOD1 dock via their highly conserved dimer interfaces in a manner that precisely orients the Cys-rich copper donor sites of CCS and the His-rich acceptor sites of SOD1 to form a copper-bridged intermediate.

Mechanism of Cu,Zn-superoxide dismutase activation by the human metallochaperone hCCS.

The mechanism for copper loading of the antioxidant enzyme copper, zinc superoxide dismutase (SOD1) by its partner metallochaperone protein is not well understood. Here we show the human copper chaperone for Cu,Zn-SOD1 (hCCS) activates either human or yeast enzymes in vitro by direct protein to protein transfer of the copper cofactor. Interestingly, when denatured with organic solvents, the apo-form of human SOD1 cannot be reactivated by added copper ion alone, suggesting an additional function of hCCS such as facilitation of an active folded state of the enzyme. While hCCS can bind several copper ions, metal binding studies in the presence of excess copper scavengers that mimic the intracellular chelation capacity indicate a limiting stoichiometry of one copper and one zinc per hCCS monomer. This protein is active and unlike the yeast protein, is a homodimer regardless of copper occupancy. Matrix-assisted laser desorption ionization-mass spectrometry and metal binding studies suggest that Cu(I) is bound by residues from the first and third domains and no bound copper is detected for the second domain of hCCS in either the full-length or truncated forms of the protein. Copper-induced conformational changes in the essential C-terminal peptide of hCCS are consistent with a "pivot, insert, and release" mechanism that is similar to one proposed for the well characterized metal handling enzyme, mercuric ion reductase.

Isometric scaling of maxillary sinus volume in hominoids.

Previous hypotheses of maxillary sinus size evolution have proposed one or more changes in the volume of the structure across hominoid phylogeny. These hypotheses have been used subsequently to support the phylogenetic placement of fossil taxa relative to the living Hominoidea. The null hypothesis, that no change in sinus volume independent of size has occurred in ape evolution, is evaluated here by scaling analysis. Mixed sex samples of adult dry crania for the extant ape genera were examined by computer tomography imaging and the volume of the maxillary sinus was obtained. Sinus volume was then regressed, using both least squares and reduced major axis models, against cranial size variables. The results clearly demonstrate that the null hypothesis of no change in relative sinus volume cannot be rejected; thus, there is no support for hypotheses that maxillary sinus volume, independent of cranial size, has changed in the course of hominoid evolution. This result, in turn, has implications for the phylogenetic placement of fossil taxa and highlights the need for the careful delineation of character states in studies of hominoid systematics.

Multiple protein domains contribute to the action of the copper chaperone for superoxide dismutase.

The copper chaperone for superoxide dismutase (SOD1) inserts the catalytic metal cofactor into SOD1 by an unknown mechanism. We demonstrate here that this process involves the cooperation of three distinct regions of the copper chaperone for SOD1 (CCS): an amino-terminal Domain I homologous to the Atx1p metallochaperone, a central portion (Domain II) homologous to SOD1, and a short carboxyl-terminal peptide unique to CCS molecules (Domain III). These regions fold into distinct polypeptide domains as revealed through proteolysis protection studies. The biological roles of the yeast CCS domains were examined in yeast cells. Surprisingly, Domain I was found to be necessary only under conditions of strict copper limitation. Domain I and Atx1p were not interchangeable in vivo, underscoring the specificity of the corresponding metallochaperones. A putative copper site in Domain II was found to be irrelevant to yeast CCS activity, but SOD1 activation invariably required a CXC in Domain III that binds copper. Copper binding to purified yeast CCS induced allosteric conformational changes in Domain III and also enhanced homodimer formation of the polypeptide. Our results are consistent with a model whereby Domain I recruits cellular copper, Domain II facilitates target recognition, and Domain III, perhaps in concert with Domain I, mediates copper insertion into apo-SOD1.

Mosaic evolution in the origin of the Hominoidea.

The initial appearance of hominoids, or apes, and the selective pressures that led to their emergence are currently disputed. Central to the argument are the proconsulids, variously described as the earliest apes or as stem catarrhines, based on facial and postcranial data, respectively. The present paper reports on incongruence and parsimony analyses applied to a combined data set. The results demonstrate that proconsulids are cladistic hominoids, and that the apparent incongruence between the data sets is due to mosaic evolution; the earliest changes in Hominoidea occurred in the face. These results suggest that the initial divergence of hominoids involved selection for an ape-like face, and was not driven by an adaptive shift to below-branch locomotion.

Structure-function analyses of the ATX1 metallochaperone.

Saccharomyces cerevisiae Atx1p represents a member of the family of metallochaperone molecules that escort copper to distinct intracellular targets. Atx1p specifically delivers copper to the Ccc2p copper transporter in the Golgi. Additionally, when overproduced, Atx1p substitutes for superoxide dismutase 1 in preventing oxidative damage; however the mechanistic overlap between these functions is unresolved. The crystal structure of Atx1p has been solved recently. By examining a surface electrostatic potential distribution, multiple conserved lysines are revealed on one face of Atx1p. An additional conserved lysine (Lys65) lies in close proximity to the metal binding site. Through site-directed mutagenesis, residues in the metal binding region including Lys65 were found to be necessary for both copper delivery to Ccc2p and for Atx1p antioxidant activity. Copper trafficking to Ccc2p also relied on the lysine-rich face of Atx1p. Surprisingly however, elimination of these lysines did not inhibit the antioxidant activity of Atx1p. We provide evidence that Atx1p does not suppress oxidative damage by a metallochaperone mechanism but may directly consume superoxide. Purified Cu-Atx1p reacts noncatalytically with superoxide anion in vitro. We conclude that the copper-trafficking and antioxidant functions of Atx1p arise from chemically and structurally distinct attributes of this metallochaperone.

Undetectable intracellular free copper: the requirement of a copper chaperone for superoxide dismutase.

The copper chaperone for the superoxide dismutase (CCS) gene is necessary for expression of an active, copper-bound form of superoxide dismutase (SOD1) in vivo in spite of the high affinity of SOD1 for copper (dissociation constant = 6 fM) and the high intracellular concentrations of both SOD1 (10 microM in yeast) and copper (70 microM in yeast). In vitro studies demonstrated that purified Cu(I)-yCCS protein is sufficient for direct copper activation of apo-ySOD1 but is necessary only when the concentration of free copper ions ([Cu]free) is strictly limited. Moreover, the physiological requirement for yCCS in vivo was readily bypassed by elevated copper concentrations and abrogation of intracellular copper-scavenging systems such as the metallothioneins. This metallochaperone protein activates the target enzyme through direct insertion of the copper cofactor and apparently functions to protect the metal ion from binding to intracellular copper scavengers. These results indicate that intracellular [Cu]free is limited to less than one free copper ion per cell and suggest that a pool of free copper ions is not used in physiological activation of metalloenzymes.

Influence of craniofacial morphology on primate paranasal pneumatization.

In order to test the hypothesis that variation in the maxillary sinus volume (MSV) of anthropoid primates is related to skull architecture, a mixed sex sample of adult primate crania covering Hominoidea, Cercopithecoidea and Ceboidea was examined using CT scans. MSV was regressed against basicranial length, using reduced major axis analysis. 2 distinct scaling patterns emerged: while a large MSV seems to be a primitive condition of Anthropoidea, it is clearly reduced in Cercopithecoidea. Although some correlations exist between MSV and different indices of the facial skeleton, they are relatively weak and differed among the 3 groups. A full appreciation of epigenetic factors and the relation of the paranasal sinuses to different cranial components is necessary to highlight the biological role of skull pneumatization.

The heme prosthetic group of lactoperoxidase. Structural characteristics of heme l and heme l-peptides.

The heme prosthetic group from the bovine milk enzyme lactoperoxidase (LPO), termed heme l, is isolated through an approach that combines proteolytic hydrolysis and reverse-phase high performance liquid chromatographic separation of the resulting digest. Application of different proteases yields either a peptide-bound heme (with trypsin and chymotrypsin) or a peptide-free heme (with proteinase K). Both heme l and heme l-peptide species were investigated by paramagnetic 1H NMR spectroscopy, electrospray mass spectrometry, and peptide sequence analysis. Paramagnetic 1H NMR experiments on the low spin bis(cyano)-Fe(III)heme l complex conclusively define the heme l structure as a 1,5-bis(hydroxymethyl) derivative of heme b. The electrospray mass spectrum of heme l confirms the two-site hydroxyl functionalization on this heme. Paramagnetic 1H NMR spectra of the high spin bis(dimethyl sulfoxide)-Fe(III) complexes of the isolated heme species provide information regarding peptide content. Sequence analyses of peptides released from two heme l-peptide species by base hydrolysis suggest that heme-protein ester linkages in lactoperoxidase occur between the two hydroxyl groups of heme l and the carboxylic side chains of glutamate 275 and aspartate 125. These results confirm the earlier reported structural proposal (Rae, T. D., and Goff, H. M. (1996) J. Am. Chem. Soc. 118, 2103-2104).

Chronic pelvic pain caused by residual ovaries and ovarian remnants.

OBJECTIVE: To determine the diagnostic effectiveness and treatment of women with chronic lower abdominal pain due to residual ovaries or ovarian remnants. DESIGN: A prospective observational study. SETTING: Tertiary referral pelvic pain clinic. SUBJECTS: Seventeen women complaining of chronic pelvic pain of up to 25 years' duration, of whom seven had residual ovaries and 10 ovarian remnant(s). MAIN OUTCOME MEASURES: Persistent lower abdominal pain, pelvic tenderness and quality of life one year post-operatively. RESULTS: Six of the seven women with residual ovaries, and nine of the 10 women with presumed ovarian remnants experienced relief of the original pain, loss of pelvic tenderness and an improved quality of life. CONCLUSIONS: Residual ovaries after hysterectomy and ovarian remnants are established causes of chronic pelvic pain. Diagnosis and surgical removal is frequently difficult. Management strategies are proposed for both conditions.

An alternative to hysterectomy? GnRH analogue combined with hormone replacement therapy.

OBJECTIVE: To assess whether GnRH analogues are effective in relieving pelvic pain and congestion and whether menopausal symptoms caused by GnRH analogues can be minimised by supplementation with low dose continuous combined hormone replacement therapy (HRT). DESIGN: Open prospective study. SETTING: Tertiary referral clinic at a teaching hospital. PATIENTS: Twenty-one women with chronic pelvic pain. INTERVENTION: Four months' therapy with goserelin 3.6 mg/month combined with continuous oestradiol valerate 1 mg daily and medroxyprogesterone acetate 5 mg daily. MAIN OUTCOME MEASURES: Visual analogue scale for pain, menopausal symptoms, bleeding patterns, uterine area, endometrial status, oestradiol concentrations and venogram scores. RESULTS: Amenorrhoea was maintained in all but two women. Endometrial atrophy was maintained despite HRT supplementation. Two women had moderate menopausal symptoms but none had severe symptoms. Significant reduction of uterine cross sectional area was maintained throughout the study. There was no significant relief of pain. CONCLUSIONS: HRT supplementation of GnRH analogues abolishes menopausal symptoms and thus may improve patient acceptability. Potentially beneficial effects such as endometrial atrophy, reduction of uterine volume and amenorrhoea were not negated by HRT. This combination is not effective in the treatment of chronic pelvic pain and congestion.

Pelvic congestion in women: evaluation with transvaginal ultrasound and observation of venous pharmacology.

Fourteen women with chronic pelvic pain due to congestion underwent transvaginal ultrasound scanning to observe changes in the diameters of dilated pelvic veins. Spontaneous fluctuations were observed, and intravenous dihydroergotamine resulted in a consistent venoconstrictor response (p = 0.0021) during 20 min observation. Transvaginal ultrasound is useful for imaging dilated pelvic veins and for the study of venous pharmacology.

Accuracy of ultrasound measurements of female pelvic organs.

Uterine size, endometrial thickness and ovarian volume were measured ultrasonically and the results compared with caliper measurements made shortly afterwards at the time of total hysterectomy and bilateral salpingo-oophorectomy. The results establish the validity of ultrasound measurements. Histological studies also confirmed the diagnosis made with ultrasound of polycystic ovaries in women complaining of pain due to pelvic congestion.

Carbon fibre composite bone plates. Development, evaluation and early clinical experience.

We compared the mechanical properties of carbon fibre composite bone plates with those of stainless steel and titanium. The composite plates have less stiffness with good fatigue properties. Tissue culture and small animal implantation confirmed the biocompatibility of the material. We also present a preliminary report on the use of the carbon fibre composite plates in 40 forearm fractures. All fractures united, 67% of them showing radiological remodelling within six months. There were no refractures or mechanical failures, but five fractures showed an unexpected reaction; this is discussed.

The effect of starch glove powder on joint and other tissues.

The purpose of this research was to establish the possible role of starch glove powder in complications following orthopaedic surgery using in vivo and in vitro techniques. Exposure of primary mouse peritoneal macrophages to starch glove powder caused 10% release of prostaglandin E2 (0.1 mg/ml, 16 h) but no increased release of lactate dehydrogenase, demonstrating that cell integrity had not been compromised. Long-term tissue reaction to starch glove powder was investigated in vivo by injection into mouse knee joints. Over a period of 52 weeks no inflammatory response was elicited, no starch was observed in the regional lymph nodes and none was found in joints after the 8th week. Starch glove powder appeared to be innocuous in the joint and although prostaglandin E2 release was stimulated in vitro, this had no apparent effect on joints in vivo.