Sequential analysis of the effects of naltrexone on the environmental mediation of self-injurious behavior.

Accumulated evidence shows that biology and the environment can mediate self-injurious behavior (SIB) in persons with mental retardation. Whether pharmacological treatment alters the environmental mediation of self-injury is unclear. Opioid antagonist effects on sequential dependencies for self-injury were studied in the context of experimental single-subject double-blind placebo-controlled designs. Direct observational data were collected for 4 adult subjects in real time on daily rate of SIB and staff interactions. Clinically significant reductions (i.e., > or = 33%) in SIB rate were observed for 3 of the 4 subjects. For all subjects, the magnitude of the sequential dependency between staff behavior and self-injury was significantly greater during treatment with naltrexone than during treatment with a placebo. Results are discussed in relation to behavioral mechanisms of action regulating medication effects for self-injury.

Preliminary study of altered skin temperature at body sites associated with self-injurious behavior in adults who have developmental disabilities.

In this study, the sensory status of 4 nonverbal adults with mental retardation and severe self-injury was examined using skin temperature measures prior to opiate antagonist treatment. Double-blind, placebo-controlled, experimental ABAB designs were used to evaluate the effects of naltrexone hydrochloride (1.5 mg/kg/day). For each participant, the body site targeted most frequently for self-injury was associated with altered skin temperature and reduced by naltrexone. In all cases, neither infrequent self-injury body sites nor non-self-injury body sites were associated with altered skin temperature. Further controlled studies are warranted to examine the value of assessing pain status and skin temperature in nonverbal patients with mental retardation and related developmental disabilities who present with tissue-damaging SIB.

A sticky entry-exit trap for sampling mosquitoes in subterranean habitats.

This paper addresses the problems of sampling adult Aedes aegypti and other mosquitoes which utilize subterranean habitats such as wells and service manholes. The sticky pipe trap is a simple device with an adhesive paper insert that can be clipped to the undersides of service manholes to record the entry and exit of adult mosquitoes through the keyhole openings. This trap was 1st used successfully in Townsville, Charters Towers, and Saunders Beach in north Queensland, Australia, in dry seasons of 1996-97 to record usage by 5 species, mainly the Aedes tremulus group and Ae. aegypti, which together comprised 91% of the 1,140 adults collected. Both males and predominantly nulliparous females were recorded exiting manholes, whereas all freshwater-breeding species entering manholes were gravid, presumably seeking oviposition sites.

Molecular mechanisms involved in the differentiation of spermatogenic stem cells.

In male mammals, spermatogenesis proceeds for the reproductive lifetime of the animal. The continuation of this process depends upon a pool of spermatogenic stem cells within the testes that undergo asymmetric division to both maintain the stem cell population and give rise to progenitors that will proceed through spermatogenesis to generate mature spermatozoa. Thus, the development of functional spermatozoa may be divided into two distinct stages. The second, the process of spermatogenesis, is dependent upon the first, the successful formation of spermatogenic stem cells. Although spermatogenesis is characterized by marked cellular differentiation, the initial stages of germ line differentiation involve an avoidance of the differentiation signals acting during embryo development. The germ line is set aside early in embryo development and, while the primordial germ cells remain refractory to the differentiation signals affecting the soma, they undergo a number of phenotypic shifts before and after colonizing the genital ridge. Upon colonization of the genital ridge, the somatic tissue of the male genital ridge directs the final differentiation events that result in the formation of spermatogenic stem cells. It is this cell population that provides the basis for the maintenance of spermatogenesis in the adult.

Lack of benefit of a single dose of synthetic human secretin in the treatment of autism and pervasive developmental disorder.

BACKGROUND: Secretin is a peptide hormone that stimulates pancreatic secretion. After recent publicity about a child with autism whose condition markedly improved after a single dose of secretin, thousands of children with autistic disorders may have received secretin injections. METHODS: We conducted a double-blind, placebo-controlled trial of a single intravenous dose of synthetic human secretin in 60 children (age, 3 to 14 years) with autism or pervasive developmental disorder. The children were randomly assigned to treatment with an intravenous infusion of synthetic human secretin (0.4 microg per kilogram of body weight) or saline placebo. We used standardized behavioral measures of the primary and secondary features of autism, including the Autism Behavior Checklist, to assess the degree of impairment at base line and over the course of a four-week period after treatment. RESULTS: Of the 60 children, 4 could not be evaluated - 2 received secretin outside the study, and 2 did not return for follow-up. Thus, 56 children (28 in each group) completed the study. As compared with placebo, secretin treatment was not associated with significant improvements in any of the outcome measures. Among the children in the secretin group, the mean total score on the Autism Behavior Checklist at base line was 59.0 (range of possible values, 0 to 158, with a larger value corresponding to greater impairment), and among those in the placebo group it was 63.2. The mean decreases in scores over the four-week period were 8.9 in the secretin group and 17.8 in the placebo group (mean difference, -8.9; 95 percent confidence interval, -19.4 to 1.6; P=0.11). None of the children had treatment-limiting adverse effects. After they were told the results, 69 percent of the parents of the children in this study said they remained interested in secretin as a treatment for their children. CONCLUSIONS: A single dose of synthetic human secretin is not an effective treatment for autism or pervasive developmental disorder.

Distal V beta promoters transcribe novel T-cell receptor-beta transcripts in early development.

The transcriptional activation of germline T-cell receptor (TCR) and immunoglobulin (Ig) genes has been proposed to promote the rearrangement of these genes. Here we report the identification of distal TCR promoters (PDs), located upstream of the previously characterized promoters in the mouse V beta 5.1 and V beta 8.1 gene segments, that are active in germline TCR genes in fetal thymus and liver in vivo. We also identified an immature T-cell clone, SL12.4, that expresses both endogenous and transfected PDs in a regulated manner in vitro. We propose that the transcription of these distal promoters in germline TCR genes may be important for inducing TCR gene rearrangements during T-cell development. Northern blot, RNase protection and reverse transcription-polymerase chain reaction (RT-PCR) analyses demonstrated that PDs are also transcribed from fully rearranged TCR genes in adult thymus, lymph node, and spleen. Although the functional significance of this expression is not known, our sequence analysis of the 5' leader in PD-derived V beta 5.1 and V beta 8.1 transcripts revealed the presence of several open reading frames (ORFs) that may encode novel polypeptides or regulate the efficiency of TCR beta translation.

Androgen regulation of the Pem homeodomain gene in mice and rat Sertoli and epididymal cells.

Although the role of homeodomain transcription factors during embryogenesis is well known, their developmental function in postnatal animals is only beginning to be understood. We examined the regulation and expression pattern of Pem, a homeodomain protein that may regulate androgen-dependent events in the testis and epididymis. Immunohistochemical analysis showed that Pem protein is expressed selectively in the nuclei of Sertoli cells during the androgen-dependent stage of the seminiferous epithelium cycle in vivo. RNase protection analysis revealed that a proximal promoter was responsible for androgen-dependent mouse Pem expression in testis and epididymis in vivo, whereas a distal promoter was used in placenta. The mouse Pem gene was expressed at approximately 10-fold higher levels in the testis than in the epididymis; conversely, the rat Pem gene was expressed at >10-fold higher levels in the epididymis than in the testis. Because androgen-binding protein has been proposed to transport androgens from the testis to the epididymis, we tested whether the > or = 20-fold higher levels of androgen-binding protein expression in the rat, compared to that of mouse, are responsible for the differential expression of Pem in these two rodent species. Studies with androgen-binding protein transgenic mice demonstrated that the species-specific difference in androgen-binding protein expression is unlikely to be responsible for the species-specific difference in Pem expression. We found that androgen is necessary but not sufficient for Pem expression, since purified Sertoli cells rapidly down-regulated Pem transcripts in culture, regardless of the presence of testosterone. We conclude that Pem gene expression in Sertoli cells requires other cell types or cellular factors in addition to androgen.

Increasing communicative interactions of young children with autism using a voice output communication aid and naturalistic teaching.

We evaluated the effects of a voice output communication aid (VOCA) and naturalistic teaching procedures on the communicative interactions of young children with autism. A teacher and three assistants were taught to use naturalistic teaching strategies to provide opportunities for VOCA use in the context of regularly occurring classroom routines. Naturalistic teaching procedures and VOCA use were introduced in multiple probe fashion across 4 children and two classroom routines (snack and play). As the procedures were implemented, all children showed increases in communicative interactions using VOCAs. Also, there was no apparent reductive effect of VOCA use within the naturalistic teaching paradigm on other communicative behaviors. Teachers' ratings of children's VOCA communication, as well as ratings of a person unfamiliar with the children, supported the contextual appropriateness of the VOCA. Probes likewise indicated that the children used the VOCAs for a variety of different messages including requests, yes and no responses, statements, and social comments. Results are discussed in regard to the potential benefits of a VOCA when combined with naturalistic teaching procedures. Future research needs are also discussed, focusing on more precise identification of the attributes of VOCA use for children with autism, as well as for their support personnel.

The rapidly evolving Pem homeobox gene and Agtr2, Ant2, and Lamp2 are closely linked in the proximal region of the mouse X chromosome.

The Pem gene encodes a homeodomain-containing protein expressed in reproductive tissue that may function as a transcription factor regulating spermatogenesis and sperm maturation. We have mapped the Pem gene to the proximal end of the mouse X chromosome, placing it within the Hprt region. Based on the mapping of Pem and other loci in three separate Mus musculus x Mus spretus backcross panels, we established the order of markers within this segment of the Hprt region as: Agtr2-Pem-Ant2-DXMit50-Lamp2-DXMit49. In contrast to some other regions of the X chromosome, which have been rearranged during the evolution of mammals, we show that the order of gene loci within this Hprt region is conserved in mice and human. The finding that the mouse Ant2 and Pem loci are tightly linked suggests that human ANT2 may be useful as a marker for isolating the human PEM gene, which has been impervious to cloning by conventional hybridization methods because of its rapid evolution.

Regulation of the long terminal repeat in visna virus by a transcription factor related to the AML/PEBP2/CBF superfamily.

The long terminal repeats of maedi visna virus strain 1514 contain a consensus AP-1 binding site which has been shown to be important in controlling virus transcription. However, this consensus site is absent in strain EV-1. Here, we have compared the ability of oligonucleotides corresponding to LTR sequences from EV-1 with those from 1514 to bind transcription factors in competitive gel retardation assays and activate reporter gene expression. The experiments demonstrated no observable binding of AP-1 to the EV-1-derived sequences and significant differences in the abilities of the 1514 and EV-1 sequences to activate transcription. However, both viral sequences interacted with a second, previously undetected, transcription factor. This factor gave specific gel shifts which were competed by an oligonucleotide containing the consensus sequence for the AML/PEBP2/CBF family of transcriptional factors, but not by control AP-1 or OCT-1 oligonucleotides. The factor was therefore denoted AML (vis). A second AML (vis) site, noted upstream of the TATA box proximal AP-1 site, gave single shifts which were competed by the downstream AML (vis) oligonucleotide. Both sites were functional in transfection assays. In gel shift retardation assays, polyclonal antisera directed against known runt domain proteins were able to supershift part of the AML (vis) binding activity in nuclear extracts from physiologically relevant cell types. The results thus suggest that the AML (vis) binding factor belongs to the AML/PEBP2/CBF family of transcription factors and may be important in controlling virus replication in these and other strains of ruminant lentiviruses.

Rapid evolution of a homeodomain: evidence for positive selection.

One often-noted feature of homeobox genes is the conservation of the homeodomain among orthologous genes from distantly related species. This sequence conservation is presumed to reflect functional conservation, which indeed has been demonstrated in several cases. We analyzed the evolution of an orphan homeobox gene, Pem, which is expressed preferentially in male and female reproductive tissue. Sequence analysis of 12 species of mice and rats indicated that the Pem gene has evolved at a remarkably high rate. The most rapidly evolving region of the Pem protein is the amino portion of the homeodomain, including the flexible N-terminal arm, helices I and II, and the linker regions between the helices. In contrast, the third helix, which is known to mediate base-specific DNA contacts in other homeodomains, is conserved in the Pem protein. Analysis of the ratio of nonsynonymous and synonymous codon substitution rates within the Pem homeodomain suggested that its divergence was driven by adaptive selection. The rate of nonsynonymous substitutions in Pem was higher than that of the sex-determination gene Sry, which also appears to have undergone directional selection over a short evolutionary period. Despite the rapid evolution of the Pem gene, we detected no Pem polymorphisms and observed no variation in the homeobox sequence among closely related Mus species. This suggests that purifying episodes followed phases in which selection pressure drove the rapid divergence of this locus. We propose that transcription factors that function in reproductive events can be subject to rapid adaptive selection.

Sequence and repeat structure variants in the long terminal repeat of maedi-visna virus EV1.

Diversity in the LTR of maedi-visna virus strain EV1 has been examined by PCR-based gene amplification using DNA from infected cells both in vitro and in experimentally infected animals. In vitro, several variant structures were found in the U3 regions of the LTR which contained repeats of sequences including presumed AP-1 and AP-4 binding sites. Although these repeat variants formed a minor fraction of the LTRs present in the proviral population, they were neither produced nor lost at a significant rate when PCR was performed on cloned viral DNA and so were unlikely to be artefacts of the isolation procedure. When LTRs were isolated from two experimentally EV1 infected sheep, repeat variant structures were found to be present in efferent lymph by 14 days postinfection (p.i.) (although not seen at 9 days p.i.). They were also present at later times and in blood. Overall sequence diversity at 9 days p.i. was reduced compared both with the infecting virus and with later times of infection. When a number of the variant LTR structures were used to drive CAT reporter gene constructs in chondrocytes, all were found to be active, although consistent differences of up to fourfold in activity were seen. However, there is no evidence from these data for strong selective pressure operating on the LTR in vivo.