A modified nick translation method used with FISH that produces reliable results with archival tissue sections

Nick translation is used to label DNA and RNA to produce probes for in situ hybridization and Northern and Southern blotting. Fluorescence in situ hybridization (FISH) is a widely applied technique used to determine chromosomal and genetic anomalies in many biological samples. Initially the technique was applied to metaphase preparations, but the usefulness of detecting genetic anomalies in solid tumors in situ has resulted in the development of modified protocols. Formalin fixed paraffin processed tissue sections present novel challenges when applying FISH; the probes must be small (between 200 and 600 base pairs) and pretreatment is necessary before the probes can be applied to tissue sections, to promote probe access to target DNA. Here we report on a modification of a nick translation method to produce a probe that can reliably be used with FISH in paraffin processed tissue sections.     

Fluorescence in situ hybridization in paraffin tissue sections: pretreatment protocol

Fluorescence in situ hybridization has found wide application in the enumeration of gene and chromosome copy number both in isolated cells and in tissue sections. However, the technique has been less widely used than would be expected in formalin-fixed paraffin processed (archival) tissue. This article describes a method for assessing archival tissue sections, following pretreatment, before applying DNA probes, that gives consistent, reliable results.     

Anthropometric study of synostotic frontal plagiocephaly: before and after fronto-orbital advancement with correction of nasal angulation

Surgical correction of synostotic frontal plagiocephaly (unilateral coronal synostosis) focuses on the asymmetry of the forehead and orbits. However, there is controversy regarding whether nasal angulation should be addressed during primary fronto-orbital advancement in infancy. This prospective study was undertaken to answer that question. Preoperative and postoperative anthropometric measurements were obtained for 19 infants with nonsyndromic synostotic frontal plagiocephaly. The measurements included nasal angulation, nasion-to-endocanthion distance, nasion-to-exocanthion distance, and exocanthion-to-tragion distance. All patients underwent bilateral parallelogrammatic fronto-orbital correction. Closing wedge nasal ostectomy was performed for group I (n = 14) and was not performed for group II (n = 5). The average age at the time of follow-up assessments was 3 years 8 months (range, 1 to 14 years) in group I and 5 years 5 months (range, 2 to 15 years) in group II. A statistically significant change was observed for patients who underwent primary correction of nasal angulation; the change correlated with improved naso-orbital symmetry, as judged with nasion-to-endocanthion and nasion-to-exocanthion measurements (p < 0.01 and p < 0.05, respectively). Group I patients exhibited an average preoperative nasal angulation of 9.15 +/- 0.8 degrees that decreased to 3.1 +/- 0.6 degrees postoperatively (p < 0.01). Group II patients exhibited an average preoperative nasal angulation of 6.4 +/- 0.7 degrees that was unchanged postoperatively at 7.2 +/- 1 degrees. The improvement in nasal angulation in group I was particularly striking because the patients in group II exhibited, on average, a lesser degree of preoperative nasal deviation (p < 0.01). This prospective comparison of fronto-orbital correction of synostotic frontal plagiocephaly with and without nasal correction confirmed an earlier study and demonstrated that angulation of the nasal pyramid does not self-correct within 5 years after traditional bilateral fronto-orbital repair. Closing wedge nasal ostectomy results in improved nasal angulation and naso-orbital symmetry, without evidence of distortion or inhibition of nasal growth.     

Patch-clamp experiments with porins extracted from a marine bacterium (Photobacterium profundum strain SS9) and reconstituted in liposomes

The reconstitution of bacterial porins in liposome bilayers for patch-clamp recording is well established. However, the solutions used in the dehydration, rehydration, and osmotic swelling of the liposomes have been developed for porins from enteric bacteria. Porins from marine bacteria normally function in contact with seawater whose ionic composition and osmotic pressure would appear to be incompatible with the established methods. Here, we show that, contrary to expectation, an established reconstitution and patch-clamp method works well with porins, mainly OmpH and OmpL, extracted from the deep-sea marine bacterium Photobacterium profundum strain SS9 and that seawater can be introduced at a supplementary stage.     

Comparison of Prevalence and Antimicrobial Susceptibilities of Campylobacter spp. Isolates from Organic and Conventional Dairy Herds in Wisconsin

The prevalence and antimicrobial susceptibilities of Campylobacter spp. isolates from bovine feces were compared between organic and conventional dairy herds. Thirty organic dairy herds, where antimicrobials are rarely used for calves and never used for cows, were compared with 30 neighboring conventional dairy farms, where antimicrobials were routinely used for animals for all ages. Fecal specimens from 10 cows and 10 calves on 120 farm visits yielded 332 Campylobacter isolates. The prevalence of Campylobacter spp. in organic and conventional farms was 26.7 and 29.1%, and the prevalence was not statistically different between the two types of farms. Campylobacter prevalence was significantly higher in March than in September, higher in calves than in cows, and higher in smaller farms than in large farms. The rates of retained placenta, pneumonia, mastitis, and abortion were associated with the proportion of Campylobacter isolation from fecal samples. The gradient disk diffusion MIC method (Etest) was used for testing susceptibility to four antimicrobial agents: ciprofloxacin, gentamicin, erythromycin, and tetracycline. Two isolates were resistant to ciprofloxacin, and none of isolates was resistant to gentamicin or erythromycin. Resistance to tetracycline was 45% (148 of 332 isolates). Tetracycline resistance was found more frequently in calves than in cows (P = 0.042), but no difference was observed between organic and conventional farms. When we used Campylobacter spp. as indicator bacteria, we saw no evidence that restriction of antimicrobial use on dairy farms was associated with prevalence of resistance to ciprofloxacin, gentamicin, erythromycin, and tetracycline.     

Double-antibody solid-phase enzyme immunoassay for the detection of staphylococcal enterotoxin A.

A simple double-antibody enzyme immunoassay that uses a microtechnique was developed for detecting staphylococcal enterotoxin A in food products. Sample preparation can be completed in less than 15 min. Assay sensitivity ranges from 0.4 ng (20-h test time) to 3.2 ng (1- to 3-h test time) of toxin per ml of prepared sample. Separation and detection of enterotoxin from spiked food products ranged between 72 and 98% of the amount added.     

A major susceptibility locus for specific language impairment is located on 13q21

Children who fail to develop language normally-in the absence of explanatory factors such as neurological disorders, hearing impairment, or lack of adequate opportunity-are clinically described as having specific language impairment (SLI). SLI has a prevalence of approximately 7% in children entering school and is associated with later difficulties in learning to read. Research indicates that genetic factors are important in the etiology of SLI. Studies have consistently demonstrated that SLI aggregates in families. Increased monozygotic versus dizygotic twin concordance rates indicate that heredity, not just shared environment, is the cause of the familial clustering. We have collected five pedigrees of Celtic ancestry that segregate SLI, and we have conducted genomewide categorical linkage analysis, using model-based LOD score techniques. Analysis was conducted under both dominant and recessive models by use of three phenotypic classifications: clinical diagnosis, language impairment (spoken language quotient <85) and reading discrepancy (nonverbal IQ minus non-word reading >15). Chromosome 13 yielded a maximum multipoint LOD score of 3.92 under the recessive reading discrepancy model. Simulation to correct for multiple models and multiple phenotypes indicated that the genomewide empirical P value is <.01. As an alternative measure, we also computed the posterior probability of linkage (PPL), obtaining a PPL of 53% in the same region. One other genomic region yielded suggestive results on chromosome 2 (multipoint LOD score 2.86, genomic P value <.06 under the recessive language impairment model). Our findings underscore the utility of traditional LOD-score-based methods in finding genes for complex diseases, specifically, SLI.