Regulation of Persistent Chemicals in Hazardous Waste: A Case Study of Washington State, USA.

Despite ongoing controversy, several strategic frameworks for defining chemicals of concern (e.g., persistent, bioaccumulative, toxic [PBT]; persistent, mobile, toxic [PMT]; persistent organic pollutant [POP]) share persistence as a key criterion. Persistence should be considered over the entire chemical life cycle from production to disposal, including hazardous waste management. As a case study, we evaluate persistence criteria in hazardous waste regulations in Washington state, USA, illustrate impacts on reported waste, and propose refinements in these criteria. Although Washington state defines persistence based on half-life (>1 y) and specific chemical groups that exceed summed concentration thresholds in waste (i.e., >0.01% halogenated organic compounds [HOCs] and >1.0% polycyclic aromatic hydrocarbons [PAHs]), persistence is typically addressed with HOC and PAH evaluation but seldom with half-life estimation. Notably, persistence is considered (with no specific criteria) in corresponding federal regulations in the United States (Resource Conservation and Recovery Act). Consequently, businesses in Washington state report annual amounts of state hazardous waste (including persistent waste) separately from federal hazardous waste. Total state-only waste, and total state and federal waste combined, nearly doubled (by weight) from 2008 to 2018. For the period 2016 to 2018, persistence criteria captured 17% of state-only waste and 2% of total state and federal waste combined. Two recommendations are proposed to improve persistence criteria in hazardous waste regulations. First, Washington state should consider aligning its half-life criterion with federal and European Union PBT definitions (e.g., 60-120 d) for consistency and provide specific methods for half-life estimation. Second, the state should consider expanding its list of persistent chemical groups (e.g., siloxanes, organometallics) with protective concentration thresholds. Ultimately, to the extent possible, Washington state should strive toward harmonizing persistence in hazardous waste regulations with corresponding criteria in global PBT, PMT, and POP frameworks. Integr Environ Assess Manag 2021;17:455-464. © 2020 SETAC.

Estimating human inbreeding coefficients: comparison of genealogical and marker heterozygosity approaches.

We have used genealogies and genomic polymorphisms to estimate individual inbreeding coefficients (F) in 50 subjects with an expected range (based on recent genealogies) of F from 0.0 to 0.0625. The estimates were based on two approaches, using genotypes respectively from 410 microsatellite markers (410-STR panel) and from 10,000 SNPs (10K-SNP panel). The latter was performed in a sub-sample of 15 individuals. We concluded that for both marker panels measures of inbreeding based on the excess of homozygosity over Hardy-Weinberg expectation were not closely correlated with 4-5 generation genealogical F-values. For the 10K-SNP panel we found two alternative measures which correlated more closely with F, based respectively on standard errors and on paired homozygosity of nearby SNPs over distances of 2-4 cM. We propose an empirical method for estimating standard errors and hence individual F-values, based on the variation between individual autosomes. This method could provide useful estimates of average F-values for groups of individuals in population-based studies of the effects of inbreeding/homozygosity on quantitative traits.

Esophageal aspiration of air through the drain tube of the ProSeal laryngeal mask.

IMPLICATIONS: Two patients experienced partial upper airway obstruction while breathing spontaneously with the ProSeal laryngeal mask airway. This resulted in esophageal aspiration of air through the drain tube.

Learning to exchange an endotracheal tube for a laryngeal mask prior to emergence.

PURPOSE: To present a stepwise training method, first critiquing laryngeal mask (LM) insertion difficulty and malpositioning, then learning how to exchange an endotracheal tube (ETT) for a LM during emergence from anesthesia. METHODS: "Learning phase:" sixty adults were enrolled in a preliminary study in which ETT / LM exchange was not performed - only LM insertion difficulty and malpositioning in the presence of an oral ETT were evaluated. After induction of anesthesia and oral intubation, a classic LM size 4 was inserted using the standard recommended technique. Number of insertion attempts and fibreoptically determined malpositions were recorded. "ETT / LM exchange phase:" we performed airway exchange in 50 patients selected from our individual practices. RESULTS: "Learning phase:" the LM was satisfactorily positioned, on first attempt, in 95% of cases. With multiple insertion attempts it was possible to place the LM in all 60 intubated patients. Unsuccessful initial placement of the LM was always due to insufficient insertion depth (5%). When fully inserted into the hypopharynx, the epiglottis could be viewed fibreoptically in 13% of cases. "ETT / LM exchange phase:" the LM was inserted successfully in all 50 patients on first attempt. No complications occurred during any exchange. CONCLUSION: We found it is easy to learn how to insert a LM in the presence of an oral ETT. The most serious malposition, occurring in 5% of first attempts, was insufficient insertion depth. The only other malposition we encountered, fibreoptic visualization of the epiglottis, is not likely to result in complete airway obstruction following endotracheal extubation under anesthesia.

Identification of polymorphisms within Disrupted in Schizophrenia 1 and Disrupted in Schizophrenia 2, and an investigation of their association with schizophrenia and bipolar affective disorder.

We have undertaken a search for polymorphic sequence variation within Disrupted in Schizophrenia 1 and Disrupted in Schizophrenia 2 (DISC1 and DISC2), which are both novel genes that span a translocation breakpoint strongly associated with schizophrenia and related psychoses in a large Scottish family. A scan of the coding sequence, intron/exon boundaries, and part of the 5' and 3' untranslated regions of DISC1, plus 2.7 kb at the 3' end of DISC2, has revealed a novel microsatellite and 15 novel single nucleotide polymorphisms (SNPs). We have tracked the inheritance of four of the SNPs through multiply affected families, and carried out case-control association studies using the microsatellite and four common SNPs on populations of patients with schizophrenia or bipolar affective disorder versus normal control subjects. Neither co-segregation with disease status nor significant association was detected; however, we could not detect linkage disequilibrium between all these markers in the control population, arguing that an even greater density of informative markers is required to test rigorously for association in this genomic region.

The genomic organisation of the metabotropic glutamate receptor subtype 5 gene, and its association with schizophrenia.

The G-protein coupled metabotropic glutamate receptors (GRMs/mGluRs) have been implicated in the aetiology of schizophrenia as they modulate the NMDA response and that of other neurotransmitters including dopamine and GABA.(1-3) Electrophysiological studies in GRM subtype 5 knockout mice reveal, in one study, a sensorimotor gating deficit characteristic of schizophrenia and in another, a key rôle for this gene in the modulation of hippocampal NMDA-dependent synaptic plasticity. In humans, GRM5 levels are increased in certain pyramidal cell neurons in schizophrenics vs controls.(6) Finally, GRM5 has been mapped to 11q14, neighbouring a translocation that segregates with schizophrenia and related psychoses in a large Scottish family, F23 (MLOD score 6.0). We determined the intron/exon structure of GRM5 and identified a novel intragenic microsatellite. A case-control association study identified a significant difference in allele frequency distribution between schizophrenics and controls (P = 0.04). This is suggestive of involvement of the GRM5 gene in schizophrenia in this population.

A modified intubating laryngeal mask for endotracheal tube exchange.

IMPLICATIONS: It is often necessary to change a patient's breathing tube (endotracheal tube). This can be a risky procedure. This report describes a technique for changing an endotracheal tube by using a modified "intubating laryngeal mask" (a commonly used airway and breathing device) and a fiberoptic bronchoscope.

Pitfalls in homozygosity mapping.

There is much interest in use of identity-by-descent (IBD) methods to map genes, both in Mendelian and in complex disorders. Homozygosity mapping provides a rapid means of mapping autosomal recessive genes in consanguineous families by identifying chromosomal regions that show homozygous IBD segments in pooled samples. In this report, we point out some potential pitfalls that arose during the course of homozygosity mapping of the enhanced S-cone syndrome gene, resulting from (1) unexpected allelic heterogeneity, so that the region containing the disease locus was missed as a result of pooling; (2) identification of a homozygous IBD region unrelated to the disease locus; and (3) the potential for inflation of LOD scores as a result of underestimation of the extent of inbreeding, which Broman and Weber suggest may be quite common.

Clinical and genetic analysis of a large North European Caucasian family affected by early-onset periodontitis.

Genetic studies of early-onset periodontitis (EOP) are hampered by several factors. These include delayed onset of the trait, an upper age limit of expression of the disease, and lack of phenotypic information for edentulous family members. Segregation analyses of families with EOP support a major locus hypothesis but fail to define clearly the criteria used for diagnosis of the relatives. Confirmation of a proposed mode of inheritance and the identification of risk genes is awaited by means of family linkage studies. It is suggested that a system can be developed for the current and retrospective diagnosis of relatives of EOP probands. In addition, it is hypothesized that the large family presented here is suitable for a linkage study. Relatives of the proband who were unavailable for a full periodontal examination, were edentulous, or were deceased, were diagnosed by means of documented clinical evidence of periodontal disease or from reported case histories. Segregation analysis was performed. Analysis of the power of the pedigree to detect linkage was carried out by means of the SIMLINK program. Three different categories were defined according to the reliability of diagnosis of EOP. Segregation analysis indicated either autosomal-dominant or X-linked-dominant inheritance in this family. The simulations showed lod scores above 3.0 for all locations of the disease gene, and for each category of diagnosis. In conclusion, a method has been developed which can be used for the diagnosis of relatives of EOP probands when ideal clinical data are unavailable. The simulations suggest that this family is suitable for a genetic linkage study with the aim of identifying the location of one or more susceptibility genes.

Mice with Y chromosome deletion and reduced Rbm genes on a heterozygous Dazl1 null background mimic a human azoospermic factor phenotype.

A subset of azoospermia or oligozoospermia patients have microdeletions in defined regions of their Y chromosome, namely the AZFa, b, and c regions. Candidate genes in humans that may cause the azoospermia factor (AZF) phenotype have been assigned to these regions and can include the DAZ and RBM genes. Part of the variability in the AZFc phenotype might be due to interaction between the effects of deleting the DAZ and RBM genes. We mimicked human deletions of RBM and DAZ in the mouse by crossing male mice with a deleted Y chromosome with a reduced number of Rbm genes (Y(d1)) to heterozygote Dazl1 null female mice to study the interaction of the Dazl1 and Rbm or other genes located in the Y(d1) deletion interval. Dazl-/+ Y(d1) animals showed a significant reduction in the sperm count (P < 0.001), an increase of abnormal sperm heads and prominent mid-piece defects of the tails compared to either mutation alone (P < 0.001). Hence, Dazl1 and the genes removed on the Y(d1) chromosome are active in different pathways contributing to different stages of spermatogenesis. Reduction of Dazl1 and Rbm genes as well as/or deletion of the Y chromosome in mice gives rise to a phenotype similar to the heterogeneous AZFc phenotype observed in humans.

Psychiatric disorder and cognitive function in a family with an inherited novel mutation of the developmental control gene PAX6.

The PAX family of developmental control genes are known to play important roles in the early patterning of the central nervous system. One member of this family, PAX6, is involved in eye development in invertebrates as well as in mouse and man, but is also widely expressed in the developing forebrain. Humans with a mutation in this gene have abnormalities of eye development, and the results presented here suggest, for the first time, that this mutation may also be associated with subtle abnormalities of frontal lobe function in the family studied. We carried out genotyping of individuals within a single family, with and without the characteristic eye abnormalities of PAX6 mutation, and only those individuals with the mutation showed significant abnormalities on tests of frontal lobe function. These individuals also had higher rates of psychiatric disorder. PAX6 is highly conserved between mouse and man, and although the neuroanatomical phenotype associated with PAX6 heterozygosity has only been studied in mice, the resultant cellular disorganization seen in mice is likely to be present in the human forebrain. Although these mice have no obvious behavioural phenotype, the results presented here suggest that humans with the equivalent mutation display a neurobehavioural phenotype.

Differences in the localization and morphology of chromosomes in the human nucleus.

Using fluorescence in situ hybridization we show striking differences in nuclear position, chromosome morphology, and interactions with nuclear substructure for human chromosomes 18 and 19. Human chromosome 19 is shown to adopt a more internal position in the nucleus than chromosome 18 and to be more extensively associated with the nuclear matrix. The more peripheral localization of chromosome 18 is established early in the cell cycle and is maintained thereafter. We show that the preferential localization of chromosomes 18 and 19 in the nucleus is reflected in the orientation of translocation chromosomes in the nucleus. Lastly, we show that the inhibition of transcription can have gross, but reversible, effects on chromosome architecture. Our data demonstrate that the distribution of genomic sequences between chromosomes has implications for nuclear structure and we discuss our findings in relation to a model of the human nucleus that is functionally compartmentalized.

Presence of multiple functional polyadenylation signals and a single nucleotide polymorphism in the 3' untranslated region of the human serotonin transporter gene.

The human serotonin transporter (hSERT) gene is a candidate for involvement in the aetiology of affective disorders. In humans, multiple transcripts of the gene have been detected by northern blot analysis of brain and other tissues. We performed 3' rapid amplification of cDNA ends to identify the common sites of polyadenylation in hSERT mRNA from human JAR cells and whole blood. Two major polyadenylation sites were identified: one 567 bp downstream of the stop codon, consistent with the usage of the polyadenylation signal AATGAA, and a second site 690 bp downstream of the stop codon. The putative polyadenylation signal upstream of this site contained a single nucleotide polymorphism (AG/TTAAC). However, allelic variation at this site did not influence polyadenylation site usage, and there were no significant differences in the abundance of the two alleles of this polymorphism between 329 control subjects, 158 individuals with major depression, and 130 individuals with bipolar affective disorder. This single nucleotide polymorphism in the 3' untranslated region of the hSERT gene should provide a useful genetic marker in the evaluation of hSERT as a candidate gene influencing susceptibility to mood disorders.

Linkage mapping in 29 Bardet-Biedl syndrome families confirms loci in chromosomal regions 11q13, 15q22.3-q23, and 16q21.

Bardet-Biedl syndrome (BBS) is a clinically and genetically heterogeneous autosomal recessive disorder characterized by retinitis pigmentosa, polydactyly, obesity, hypogenitalism, mental retardation, and renal anomalies. To detect linkage to BBS loci, 29 BBS families, of mixed but predominantly European ethnic origin, were typed with 37 microsatellite markers on chromosomes 2, 3, 11, 15, 16, and 17. The results show that an estimated 36-56% of the families are linked to the 11q13 chromosomal site (BBS1) previously described by M. Leppert et al. (1994, Nature Genet. 7, 108-112), with the gene order cen-D11S480-5 cM-BBS1-3 cM-D11S913/D11S987-qter. A further 32-35% of the families are linked to the BBS4 locus, reported by R. Carmi et al. (1995, Hum. Mol. Genet. 4, 9-13) in chromosomal region 15q22.3-q23, with the gene order cen-D15S125-5 cM-BBS4-2 cM-D15S131/D15S204-qter. Three consanguineous BBS families are homozygous for three adjacent chromosome 15 markers, consistent with identity by descent for this region. In one of these families haplotype analysis supports a localization for BBS4 between D15S131 and D15S114, a distance of about 2 cM. Weak evidence of linkage to the 16q21 (BBS2) region reported by A. E. Kwitek-Black et al. (1993, Nature Genet. 5, 392-396) was observed in 24-27% of families with the gene order cen-D16S408-2 cM-BBS2-5 cM-D16S400. A fourth group of families, estimated at 8%, are unlinked to all three of the above loci, showing that at least one other BBS locus remains to be found. No evidence of linkage was found to markers on chromosome 3, corresponding to the BBS3 locus, reported by V. C. Sheffield et al. (1994, Hum. Mol. Genet. 3, 1331-1335), or on chromosome 2 or 17, arguing against the involvement of a BBS locus in a patient with a t(2;17) translocation.

European Gene Mapping Project (EUROGEM): breakpoint panels for human chromosomes based on the CEPH reference families. Centre d'Etude du Polymorphisme Humain.

Meiotic breakpoint panels for human chromosomes 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 15, 17, 18, 20 and X were constructed from genotypes from the CEPH reference families. Each recombinant chromosome included has a breakpoint well-supported with reference to defined quantitative criteria. The panels were constructed at both a low-resolution, useful for a first-pass localization, and high-resolution, for a more precise placement. The availability of such panels will reduce the number of genotyping experiments necessary to order new polymorphisms with respect to existing genetic markers. This paper shows only a representative sample of the breakpoints detected. The complete data are available on the World Wide Web (URL http:/(/)www.icnet.uk/axp/hgr/eurogem++ +/HTML/data.html) or by anonymous ftp (ftp.gene.ucl.ac.uk in/pub/eurogem/maps/breakpoints).

Recombination patterns around the breakpoints of a balanced 1;11 autosomal translocation associated with major mental illness.

The frequency and extent of pairing failure around human translocations are unknown. We have examined the pattern of recombination around the breakpoints of a balanced autosomal translocation t(1;11) (q43;q21) associated with major mental illness. DNA was available from 17 carriers and 10 non-translocation carriers with meioses involving four generations. The derivative 1 and 11 chromosomes were also isolated in somatic cell hybrids and used to confirm phase. We have genotyped pedigree members using 20 polymorphic markers within 10 cM on either side of both chromosome 1 and 11 breakpoints. We find no significant reduction of recombination in the vicinity of either breakpoint. However we estimate that there are insufficient meioses even in this large family to make a meaningful interpretation and suggest that sperm typing alone can answer these interesting questions.

Retinitis pigmentosa families showing apparent X linked inheritance but unlinked to the RP2 or RP3 loci.

Three families with retinitis pigmentosa (RP) are described in which the disorder shows apparent X linked inheritance but does not show linkage to the RP2 and RP3 regions of the short arm of the X chromosome. The families are also inconsistent with a localisation of the disease gene between DXS164 and DXS28. In one case, reassessment of the family in the light of these results suggested that the family may have an autosomal dominant form of RP. The remaining two families are consistent with X linkage and suggest the possibility of a new X linked RP (XLRP) locus. These families highlight the difficulties in determining the mode of inheritance on the basis of pedigree structure and clinical data alone. Molecular genetics plays an important role in confirming the mode of inheritance and in detecting potential misclassifications, particularly in a group of disorders as heterogeneous as RP. They emphasise that caution is required in genetic counselling of RP families, particularly in the absence of any molecular genetic analysis.

Genetic analysis of a kindred with X-linked mental handicap and retinitis pigmentosa.

A kindred is described in which X-linked nonspecific mental handicap segregates together with retinitis pigmentosa. Carrier females are mentally normal but may show signs of the X-linked retinitis pigmentosa carrier state and become symptomatic in their later years. Analysis of polymorphic DNA markers at nine loci on the short arm of the X chromosome shows that no crossing-over occurs between the disease and Xp11 markers DXS255, TIMP, DXS426, MAOA, and DXS228. The 90% confidence limits show that the locus is in the Xp21-q21 region. Haplotype analysis is consistent with the causal gene being located proximal to the Xp21 loci DXS538 and 5'-dystrophin on the short arm of the X chromosome. The posterior probability of linkage to the RP2 region of the X chromosome short arm (Xp11.4-p11.23) is .727, suggesting the possibility of a contiguous-gene-deletion syndrome. No cytogenetic abnormality has been identified.

Differential epidural block. Does the choice of local anesthetic matter?

BACKGROUND AND OBJECTIVES: It is well established that spinal anesthesia results in a differential block to the sensations of pinprick and cold temperature discrimination. However, the existence of differential block during epidural anesthesia has not always been accepted. Recently, it has been shown that lumbar epidural anesthesia with chloroprocaine and lidocaine produces a differential block to pinprick and cold sensation. The purpose of this study was to determine if the choice of local anesthetic used for epidural anesthesia has any influence on the relative levels of anesthesia, analgesia, and cold sensation. METHODS: The authors studied nine healthy subjects; each was studied three times and received one of three local anesthetics (0.75% bupivacaine, 2% lidocaine, and 3% chloroprocaine) via an epidural catheter placed into the second or third lumbar epidural space. The authors tested the following modalities compared to an unblocked dermatome: anesthesia, loss of sensation to pinprick; analgesia, loss of an equally sharp sensation to pinprick; and cold sensation, loss of cold sensation to alcohol. RESULTS: Twenty minutes after injection of the local anesthetic, zones of differential sensory block existed for all three agents tested. Anesthesia and analgesia were the most caudad and cephalad, respectively, while loss-to-cold sensation was found to be between these two levels. There was no significant difference in the dermatomal level achieved among the three local anesthetics tested. Sensory testing data observed 10 minutes later showed that no significant change had occurred. CONCLUSIONS: This study reaffirms the existence of differential sensory block during epidural anesthesia and establishes that the observed differential block appears to be independent of the local anesthetic used.

Heterogeneity analysis in 40 X-linked retinitis pigmentosa families.

Analysis of genetic heterogeneity in 40 kindreds with X-linked retinitis pigmentosa (XLRP), with 20 polymorphic markers, showed that significant heterogeneity is present (P = .001) and that 56% of kindreds are of RP3 type and that 26% are of RP2 type. The location of the RP3 locus was found to be 0.4 cM distal to OTC in the Xp21.1 region, and that of the RP2 locus was 6.5 cM proximal to DXS7 in Xp11.2-p11.3. Bayesian probabilities of linkage to RP2, RP3, or to neither locus were calculated. This showed that 20 of 40 kindreds could be assigned to one or the other locus, with a probability > .70 (14 kindreds with RP3 and 6 kindreds with RP2 disease). A further three kindreds were found to be unlinked to either locus, with a probability > .8. The remaining 17 kindreds could not be classified unambiguously. This highlights the difficulty of classifying families in the presence of genetic heterogeneity, where the two loci are separated by an estimated 16 cM.