TEMPO® TVC for the Enumeration of Aerobic Mesophilic Flora in Foods: Collaborative Study

The automated system for enumeration of total viable count (TVC) in foods, TEMPO® TVC, uses a dehydrated culture medium and an enumeration card containing 48 wells across 3 different dilutions for the automatic determination of the most probable number (MPN). The alternative method was compared in a multilaboratory collaborative study to AOAC Method 966.23 for determination of aerobic plate count for nondairy products and the Standard Methods for the Examination of Dairy Products (SMEDP) Standard Plate Count for dairy products. Five food types, raw ground beef, raw ground chicken, cooked whitefish fillets, bagged lettuce, and milk, were analyzed for TVC by 14 collaborating laboratories throughout the United States and Canada. Three lots of naturally contaminated food products representing a wide range of counts were tested for each of the 5 food types. The study demonstrated that the overall repeatability, reproducibility, and mean log counts of the TEMPO TVC method were statistically comparable to those of the 2 standard methods at the 5 level.

The relative contributions of brain, cerebrospinal fluid-filled structures and non-neural tissue volumes to occipital-frontal head circumference in subjects with autism

An increased prevalence of macrocephaly defined by occipital-frontal circumference (OFC) is a consistent finding in autism. Several possible mechanisms have been proposed, the most compelling being early brain overgrowth. However, the proportion of non-neural tissues (NNT) that contribute to OFC has not been reported. Using quantitative magnetic resonance imaging (MRI) methods we analyzed the relationships between OFC and total brain (TBV), ventricular, surface cerebrospinal fluid (CSF)/meningeal, and NNT volumes in subjects with autism. Sixty male subjects (34 autistic; 26 controls) seven years of age and older were used in this study. Compared to other measures, NNT volume was most significantly related to OFC (r values > 0.8, p<or=0.001), though NNT volume did not differ between the groups. Ventricular volume was also uniformly related to OFC (r approximately 0.3, p> 0.06). In contrast, the OFC-TBV relationship was less robust in those with autism (r=0.25, p<or=0.09) and only significant in the controls (r=0.58, p<or=0.001). Conversely, subjects with autism had a more robust and significantly different relationship between subarachnoid CSF/meningeal volume than controls (r=0.53 and 0.24; p<or=0.001 and 0.12, respectively). Possible explanations for these findings are discussed in the context of potential OFC differences that may occur in accelerated early brain growth associated with autism.

Autism and the serotonin transporter: the long and short of it

Autism is a neurodevelopmental disorder manifesting early in childhood. Some symptoms of autism are alleviated by treatment with selective serotonin reuptake inhibitors, which are known to interact with the serotonin transporter. Moreover, variation in the gene that encodes the transporter (SLC6A4), especially the HTTLPR locus, is known to modulate its expression. It is natural, therefore, to evaluate whether this variation plays a role in liability to autism. We investigated the impact of alleles at HTTLPR and three other loci in SLC6A4 by using a large, independent family-based sample (390 families, 1528 individuals) from the NIH Collaborative Programs of Excellence in Autism (CPEA) network. Allele transmissions to individuals diagnosed with autism were biased only for HTTLPR, both for the narrow diagnosis of autism (P=0.035) and for the broader diagnosis of autism spectrum (P=0.007). The short allele of HTTLPR was significantly overtransmitted. Investigation of haplotype transmissions suggested that, in our data, biased transmission was only due to HTTLPR. With respect to this locus, there are now seven of 12 studies reporting significant transmission bias of HTTLPR alleles, a noteworthy result in itself. However, the studies with significant findings are almost equally divided between overtransmission of short and overtransmission of long alleles. We place our results within this extremely heterogeneous field of studies. Determining the factors influencing the relationship between autism phenotypes and HTTLPR variation, as well as other loci in SLC6A4, could be an important advance in our understanding of this complex disorder.

Multisite, double-blind, placebo-controlled trial of porcine secretin in autism

OBJECTIVE

To examine the efficacy of intravenous porcine secretin for the treatment of autistic disorder.

METHOD

Randomized, double-blind, placebo-controlled, crossover design. Fifty-six subjects with autistic disorder received either a secretin or placebo infusion at baseline and the other substance at week 4. Subjects were given the Autism Diagnostic Observation Schedule (ADOS) and other pertinent developmental measures at baseline and at weeks 4 and 8 to assess drug effects.

RESULTS

For the primary efficacy analysis, change of ADOS social-communication total score from week 0 to week 4, no statistically significant difference was obtained between placebo (-0.8 +/- 2.9) and secretin groups (-0.6 +/- 1.4; t54 = 0.346, p < .73). The other measures showed no treatment effect for secretin compared with placebo.

CONCLUSION

There was no evidence for efficacy of secretin in this randomized, placebo-controlled, double-blind trial.

Double-blind, placebo-controlled study of amantadine hydrochloride in the treatment of children with autistic disorder

OBJECTIVE

To test the hypothesis that amantadine hydrochloride is a safe and effective treatment for behavioral disturbances--for example, hyperactivity and irritability--in children with autism.

METHOD

Thirty-nine subjects (intent to treat; 5-19 years old; IQ > 35) had autism diagnosed according to DSM-IV and ICD-10 criteria using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule-Generic. The Aberrant Behavior Checklist-Community Version (ABC-CV) and Clinical Global Impressions (CGI) scale were used as outcome variables. After a 1-week, single-blind placebo run-in, patients received a single daily dose of amantadine (2.5 mg/kg per day) or placebo for the next week, and then bid dosing (5.0 mg/kg per day) for the subsequent 3 weeks.

RESULTS

When assessed on the basis of parent-rated ABC-CV ratings of irritability and hyperactivity, the mean placebo response rate was 37% versus amantadine at 47% (not significant). However, in the amantadine-treated group there were statistically significant improvements in absolute changes in clinician-rated ABC-CVs for hyperactivity (amantadine -6.4 versus placebo -2.1; p = .046) and inappropriate speech (-1.9 versus 0.4; p = .008). CGI scale ratings were higher in the amantadine group: 53% improved versus 25% (p = .076). Amantadine was well tolerated.

CONCLUSIONS

Parents did not report statistically significant behavioral change with amantadine. However, clinician-rated improvements in behavioral ratings following treatment with amantadine suggest that further studies with this or other drugs acting on the glutamatergic system are warranted. The design of these and similar drug trials in children with autistic disorder must take into account the possibility of a large placebo response.

The Tourette syndrome diagnostic confidence index: development and clinical associations

BACKGROUND

The clinical characteristics of Tourette syndrome (TS) present challenges for the systematic determination of whether individuals are affected and severity. Vocal and motor tics wax and wane, decrease over time, and may be voluntarily suppressible, and therefore may be absent at interview. Current instruments measure symptoms at interview or rate symptom severity only.

METHOD

To minimize error in case ascertainment and produce an instrument measuring lifetime likelihood of having had TS, clinical members of the American Tourette Syndrome Association International Genetic Collaboration developed the Diagnostic Confidence Index (DCI). The expert group worked collaboratively with progressive revision in consensus workshops using existing diagnostic criteria as guidelines. The DCI produces a score from 0 to 100 that is a measure of the likelihood of having or ever having had TS.

RESULTS

The DCI was administered to 280 consecutive patients with TS attending a TS clinic; 264 (94%) completed it, indicating high feasibility and acceptability. Its correlation with other instruments and associations with psychopathology provide support for its being a lifetime measure of TS.

CONCLUSIONS

The DCI is a useful, practicable instrument in the clinic or research practice allowing an assessment of lifetime likelihood of TS. Further work is needed to test the DCI's psychometric properties, such as its validity and reliability in populations of interest.

Absence of linkage and linkage disequilibrium to chromosome 15q11-q13 markers in 139 multiplex families with autism

Chromosomal region 15q11-q13 has been implicated to harbor a susceptibility gene or genes underlying autism. Evidence has been derived from the existence of cytogenetic anomalies in this region associated with autism, and the report of linkage in a modest collection of multiplex families. Most recently, linkage disequilibrium with the marker GABRB3-155CA2 in the candidate locus GABRB3, located in this region, has been reported. We searched for linkage using eight microsatellite markers located in this region of chromosome 15 in 147 affected sib-pairs from 139 multiplex autism families. We also tested for linkage disequilibrium in the same set of families with the same markers. We found no evidence for excess allele sharing (linkage) for the markers in this region. Also, we found no evidence of linkage disequilibrium, including for the locus GABRB3-155CA2. Thus, it appears that the role of this region of chromosome 15 is minor, at best, in the majority of individuals with autism.

A genomic screen of autism: evidence for a multilocus etiology

We have conducted a genome screen of autism, by linkage analysis in an initial set of 90 multiplex sibships, with parents, containing 97 independent affected sib pairs (ASPs), with follow-up in 49 additional multiplex sibships, containing 50 ASPs. In total, 519 markers were genotyped, including 362 for the initial screen, and an additional 157 were genotyped in the follow-up. As a control, we also included in the analysis unaffected sibs, which provided 51 discordant sib pairs (DSPs) for the initial screen and 29 for the follow-up. In the initial phase of the work, we observed increased identity by descent (IBD) in the ASPs (sharing of 51.6%) compared with the DSPs (sharing of 50.8%). The excess sharing in the ASPs could not be attributed to the effect of a small number of loci but, rather, was due to the modest increase in the entire distribution of IBD. These results are most compatible with a model specifying a large number of loci (perhaps >/=15) and are less compatible with models specifying </=10 loci. The largest LOD score obtained in the initial scan was for a marker on chromosome 1p; this region also showed positive sharing in the replication family set, giving a maximum multipoint LOD score of 2.15 for both sets combined. Thus, there may exist a gene of moderate effect in this region. We had only modestly positive or negative linkage evidence in candidate regions identified in other studies. Our results suggest that positional cloning of susceptibility loci by linkage analysis may be a formidable task and that other approaches may be necessary.

Intravascular stents in congenital heart disease: short- and long-term results from a large single-center experience

OBJECTIVES

This report describes the results of the Food and Drug Administration's phase 1 and 2 clinical trials of intravascular stents at Texas Children's Hospital.

BACKGROUND

Since the late 1980s, intravascular stent implantation for the treatment of arterial and venous stenoses in congenital heart disease has been highly successful.

METHODS

Stents were placed in postoperative pulmonary artery (PA) stenoses, congenital PA stenoses or stenoses of systemic veins/venous anastomoses. Prospective collection of data according to protocol was done before intervention, after stent implantation and at follow-up catheterization.

RESULTS

At stent implantation, pressure gradients decreased significantly in all three groups (mean +/- SD): from 46 +/- 25 to 10 +/- 13 mm Hg in postoperative PA stenoses (p < 0.001); from 71 +/- 45 to 15 +/- 21 mm Hg in congenital PA stenoses (p < 0.001); and from 7 +/- 6 to 1 +/- 2 mm Hg in stenoses of systemic veins/venous anastomoses stenoses (p < 0.001). Vessel diameters markedly increased: from 6 +/- 3 to 12 +/- 3 mm in postoperative PA stenoses (p < 0.001); from 3 + 1 to 9 + 1 mm in congenital PA stenoses (p < 0.001); and from 3 +/- 4 to 12 +/- 4 mm in stenoses of systemic veins/venous anastomoses (p < 0.001). In the postoperative and congenital PA stenoses groups, right ventricular pressure decreased (right ventricular pressure indexed to femoral artery pressure ratio): from 0.63 +/- 0.2 to 0.41 +/- 0.02 (p < 0.001) and from 0.71 +/- 0.3 to 0.55 +/- 0.35 (p = 0.04), respectively. Perfusion to a single affected lung increased from 31 +/- 17% to 46 +/- 14% (p < 0.001). On recatheterization (mean 14 months), results varied minimally. Repeat angioplasty of residual stent stenoses was safe and effective. Complications included four early patients with stent migration, three with stent thrombosis and two deaths. There were no late complications. Significant restenosis occurred in only three patients.

CONCLUSIONS

Intravascular stents for the treatment of vascular stenoses in congenital heart disease provide excellent immediate and long-term results.

Predicting diabetic control from competence, adherence, adjustment, and psychopathology

OBJECTIVE

To determine what psychological and behavioral factors were most predictive of diabetic control.

METHOD

Seventy-nine youths with diabetes were assessed cross-sectionally, using youths' reports of self-esteem, anxiety, and attitudes about diabetes, and parents' reports of competence and psychopathology (from the Child Behavior Checklist) and diabetic adherence as independent variables. Glycosylated hemoglobin A1c was the dependent variable, reflecting diabetic control. After the effects of several background variables were partialed out, a principal-components analysis grouped the substantive variables into three larger components.

RESULTS

Among the background variables, duration of illness and family size significantly predicted diabetic control. Among substantive components, Competence/Adherence (including Total Competence, dietary compliance, and frequency of blood glucose checks) was highly predictive of diabetic control, primarily due to the effect of Total Competence. Adjustment (including self-esteem, anxiety levels, and attitudes about diabetes) and Psychopathology were less predictive. A model was constructed showing the relationships between these predictive components and diabetic control.

CONCLUSIONS

In this generally well-adjusted sample, that Total Competence, more than other measures, predicted diabetic control suggests it could be used by clinicians to anticipate diabetic youths at risk.

Molecular analysis and test of linkage between the FMR-1 gene and infantile autism in multiplex families

Approximately 2%-5% of autistic children show cytogenetic evidence of the fragile X syndrome. This report tests whether infantile autism in multiplex autism families arises from an unusual manifestion of the fragile X syndrome. This could arise either by expansion of the (CGG)n trinucleotide repeat in FMR-1 or from a mutation elsewhere in the gene. We studied 35 families that met stringent criteria for multiplex autism. Amplification of the trinucleotide repeat and analysis of methylation status were performed in 79 autistic children and in 31 of their unaffected siblings, by Southern blot analysis. No examples of amplified repeats were seen in the autistic or control children or in their parents or grandparents. We next examined the hypothesis that there was a mutation elsewhere in the FMR-1 gene, by linkage analysis in 32 of these families. We tested four different dominant models and a recessive model. Linkage to FMR-1 could be excluded (lod score between -24 and -62) in all models by using probes DXS548, FRAXAC1, and FRAXAC2 and the CGG repeat itself. Tests for heterogeneity in this sample were negative, and the occurrence of positive lod scores in this data set could be attributed to chance. Analysis of the data by the affected-sib method also did not show evidence for linkage of any marker to autism. These results enable us to reject the hypothesis that multiplex autism arises from expansion of the (CGG)n trinucleotide repeat in FMR-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetics of autism: characteristics of affected and unaffected children from 37 multiplex families

Evidence from twin and family studies strongly suggests that genetic factors play a prominent role in the etiology of some cases of infantile autism. Genetic factors would be expected to be especially strong in families with multiple autistic members (multiplex families). This report describes the identification and evaluation of 44 families with two or more autistic children collected as part of a genetic linkage study in autism. Families were referred with a presumptive classification of multiplex autism. Children referred as autistic, as well as their presumptively normal siblings, were assessed using the Autism Diagnostic Interview (ADI) and the Autism Diagnostic Observation Scale (ADOS). Thirty-seven of the 44 families (87%) had at least two children who met diagnostic criteria for autism on the ADI. Of the total group of 117 children evaluated in those families, 83 (71%) met all ADI criteria and could be unambiguously classified as autistic (affected), 26 (22%) met none of the ADI criteria and were classified as not autistic (unaffected), and 8 (7%) were classified as uncertain because they met one or more but not all of the ADI cutpoints. Autistic siblings were not significantly concordant for most autism characteristics, for IQ, or for verbal ability. Significant concordances were found, however, for behaviors related to rituals and repetitive play, and for social impairments in the expression and understanding of facial expressions of emotion.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiplane gallium tomography in assessment of occupational chest diseases

Gallium-67 scintigraphy is helpful in the evaluation of inflammatory, respiratory diseases. Single-photon emission computed tomography (SPECT) provides three-dimensional tomographic reconstruction of radioisotope distribution in the body. The addition of SPECT to gallium-67 scanning in 27 patients demonstrated an improvement in the sensitivity for detecting the presence and extent of interstitial occupational lung disease. This technique may provide earlier detection of parenchymal lung changes than can the chest x-ray and planar scanning in some patients with asbestosis. Findings in six patients with asbestosis are reported.

Measurement of energy and angular distributions of extreme ultraviolet photoelectrons

Instrumentation for measuring the energy distribution of photoelectrons as a function of emission angle from the cathode normal is briefly described. ata were obtained at pressures near 10(-6) Torr for highwork-function polycrystalline metal cathodes of Al, Ni, Cu, and W, irradiated at several wavelengths between 460 A and 1048 A. The energy distribution curves appear to show a selective attenuation of lower energy photoelectrons as the emission angle is increased from the surface normal. Preliminary angular distribution curves for Ni are approximately cosine in nature, but those for Al exhibit departures from a cosine distribution.

Pigment Incorporation in GR-S through Latex

The physical properties of GR-S gum stock are decidedly inferior to those of natural-rubber gum stock, and they have to be greatly enhanced for practical use of the elastomer. At present these physical properties are augmented to the greatest degree by compounding with reinforcing pigments, especially carbon blacks. Furthermore, experience has shown that, for a given pigment, the reinforcement it affords is proportional to the degree to which it is dispersed in the elastomer. A thorough dispersion of pigment on the mill or in the Banbury mixer is not feasible with schedules which can be applied in the factory, particularly with those pigments which are more difficult to disperse. A study of the relation between the characteristics of pigments used as fillers in GR-S and their reinforcing properties indicated that the particle size of the pigment was the predominant characteristic associated with reinforcing ability. The finer carbon blacks yielded the greatest reinforcement, measured by ultimate tensile strength; also, a fine grade of magnesium oxide yielded compounds with tensile strengths approximately equal to stocks made with blacks of the same particle size. Stocks made from a coarser magnesium oxide were considerably lower in tensile strength, and zinc oxides and calcium carbonates fell roughly in the order of their particle sizes. The calcium carbonates, zinc oxides, and magnesium oxides had to be worked on the mill much more than the carbon blacks to develop maximum reinforcement; and, even though well worked, the finest zinc oxide and calcium carbonate did not yield compounds with properties which their particle size indicated they should have. It was felt that this was due to inability to disperse these materials properly on the mill; thus their effective particle size in the compound was much greater than their ultimate size. Accordingly, a better means was sought to disperse fillers in GR-S than that afforded by milling. It was known that excellent dispersions of pigments could be made in water with the aid of dispersing agents. It was also reported that the polymer particles in GR-S latex were very finely divided, less than one-tenth the diameter of particles in natural rubber latex. If, then, a water suspension of well dispersed pigment was mixed with latex, and the filler and polymer were precipitated or coagulated simultaneously, it was thought that the pigment might be more thoroughly dispersed in polymer than it would be through dry milling; the physical properties of compounds made in this manner should then show improvement over those made on the mill.