Associations between the postpartum uterine and vaginal microbiota and the subsequent development of purulent vaginal discharge vary with dairy cow breed and parity

The objective of this study was to characterize the species composition and functional potential of the vaginal and uterine microbiota at 1 wk postpartum in dairy cows diagnosed with or without purulent vaginal discharge (PVD) at 3 wk postpartum. The hypothesis was that differences in the vaginal and uterine microbiota between cows diagnosed with (PVD+) or without (PVD-) PVD were dependent on parity and breed. Cytobrush samples of the vagina and uterus were collected at 1 wk postpartum from 36 Holstein-Friesian (7 primiparous and 29 multiparous) and 29 Jersey (10 primiparous and 19 multiparous) cows. Microbial DNA was isolated from each sample and processed for shotgun metagenomic sequencing. The odds of multiparous cows being diagnosed as PVD+ was less compared with primiparous cows (OR = 0.21). Neither the α-diversity nor β-diversity of the uterine and vaginal microbiota were associated with PVD but the β-diversity was different between breeds and between parities. In the vagina of primiparous cows, differences in the microbiota of PVD- and PVD+ cows were minor, but the microbiota of multiparous PVD+ cows had greater relative abundance of Fusobacterium necrophorum, Trueperella pyogenes, Porphyromonas levii, and greater functional potential for amino acid and protein synthesis, energy metabolism, and growth compared with PVD- cows. The uterus of primiparous PVD+ cows had lesser relative abundance of Bacteroides heparinolyticus compared with PVD- cows. In the uterine microbiota, differences included greater functional potential for cellulose biosynthesis and fucose catabolism in multiparous PVD+ cows compared with PVD- cows. In the uterine microbiota of primiparous PVD+ cows, the functional potential for gram-negative cell wall synthesis and for negative regulation of tumor necrosis factor signaling was lesser compared with multiparous PVD+ cows. In the vagina of Holstein-Friesian PVD+ cows, the relative abundance of Caviibacter abscessus was greater whereas in the vagina of Jersey PVD+ cows the relative abundance of Catenibacterium mitsuokai, Finegoldia magna, Klebsiella variicola, and Streptococcus anginosus was greater compared with PVD- cows. In the uterine microbiota of Holstein-Friesian cows, the functional potential for spermidine biosynthesis was reduced compared with PVD- cows. In summary, differences in the species composition and functional potential of the vaginal and uterine microbiota between PVD- and PVD+ cows were dependent on parity and breed. The findings suggest that alternative strategies may be required to treat PVD for different parities and breeds of dairy cow.

Investigation of the gut microbiome, bile acid composition and host immunoinflammatory response in a model of azoxymethane-induced colon cancer at discrete timepoints

BACKGROUND

Distinct sets of microbes contribute to colorectal cancer (CRC) initiation and progression. Some occur due to the evolving intestinal environment but may not contribute to disease. In contrast, others may play an important role at particular times during the tumorigenic process. Here, we describe changes in the microbiota and host over the course of azoxymethane (AOM)-induced tumorigenesis.

METHODS

Mice were administered AOM or PBS and were euthanised 8, 12, 24 and 48 weeks later. Samples were analysed using 16S rRNA gene sequencing, UPLC-MS and qRT-PCR.

RESULTS

The microbiota and bile acid profile showed distinct changes at each timepoint. The inflammatory response became apparent at weeks 12 and 24. Moreover, significant correlations between individual taxa, cytokines and bile acids were detected. One co-abundance group (CAG) differed significantly between PBS- and AOM-treated mice at week 24. Correlation analysis also revealed significant associations between CAGs, bile acids and the bile acid transporter, ASBT. Aberrant crypt foci and adenomas were first detectable at weeks 24 and 48, respectively.

CONCLUSION

The observed changes precede host hyperplastic transformation and may represent early therapeutic targets for the prevention or management of CRC at specific timepoints in the tumorigenic process.

193 ARE OLDER PATIENTS IN IRELAND BEING ADEQUATELY SCREENED FOR DELIRIUM? RESULTS FROM AN IRISH PERIPHERAL HOSPITAL

Background

Delirium is associated with increased morbidity and mortality in the older person and still remains poorly detected. The Health Service Executive (HSE) has clear algorithms and guidelines which suggest that any person over the age of 65, especially so for patients with pre-existing dementia, presenting to the Emergency Department (ED) or Acute Medical Assessment Unit (AMAU) should be screened for delirium using the 4AT test. An earlier retrospective audit carried out by the authors in the same hospital showed that only 9% of patients with diagnosed delirium had a 4AT test at any point during inpatient stay and 0% had one on admission. We designed a prospective audit to assess what proportion of patients over 65 coming through the Acute Medical Assessment Unit (AMAU) had a delirium screening test performed on admission.

Methods

We reviewed the admission notes of all patients over 65 admitted through the AMAU over a continuous 14 day period from 10/11/20 to 24/11/2020. The admission notes were reviewed within 24 hours of admission. Exclusion criteria included patients presenting delirium tremens and patients presenting with a stroke.

Results

119 patients were identified. The mean age was 78.1 years. 20 (16.8%) had previously diagnosed dementia. 0 patients had a delirium screening test conducted by AMAU/ED staff on admission. 2 (1.7%) had 4AT tests done by members of the Geriatric Emergency Medical Services (GEMS) team within 24 hours. The GEMS team only sees patients who fulfill certain criteria on admission. 10 (8.4%) had ‘delirium’ listed on their differential diagnoses.

Conclusion

Our results show that the older patient being admitted through the AMAU in this hospital in Ireland is not being adequately screened for delirium. Additionally, even when delirium was suspected, delirium screening tools were not being implemented for further assessment. More needs to be done to ensure patients over 65 are assessed as per guidelines.

Investigating the Role of Diet and Exercise in Gut Microbe-Host Cometabolism

We investigated the individual and combined effects of diet and physical exercise on metabolism and the gut microbiome to establish how these lifestyle factors influence host-microbiome cometabolism. Urinary and fecal samples were collected from athletes and less active controls. Individuals were further classified according to an objective dietary assessment score of adherence to healthy dietary habits according to WHO guidelines, calculated from their proton nuclear magnetic resonance (1H-NMR) urinary profiles. Subsequent models were generated comparing extremes of dietary habits, exercise, and the combined effect of both. Differences in metabolic phenotypes and gut microbiome profiles between the two groups were assessed. Each of the models pertaining to diet healthiness, physical exercise, or a combination of both displayed a metabolic and functional microbial signature, with a significant proportion of the metabolites identified as discriminating between the various pairwise comparisons resulting from gut microbe-host cometabolism. Microbial diversity was associated with a combination of high adherence to healthy dietary habits and exercise and was correlated with a distinct array of microbially derived metabolites, including markers of proteolytic activity. Improved control of dietary confounders, through the use of an objective dietary assessment score, has uncovered further insights into the complex, multifactorial relationship between diet, exercise, the gut microbiome, and metabolism. Furthermore, the observation of higher proteolytic activity associated with higher microbial diversity indicates that increased microbial diversity may confer deleterious as well as beneficial effects on the host.IMPORTANCE Improved control of dietary confounders, through the use of an objective dietary assessment score, has uncovered further insights into the complex, multifactorial relationship between diet, exercise, the gut microbiome, and metabolism. Each of the models pertaining to diet healthiness, physical exercise, or a combination of both, displayed a distinct metabolic and functional microbial signature. A significant proportion of the metabolites identified as discriminating between the various pairwise comparisons result from gut microbe-host cometabolism, and the identified interactions have expanded current knowledge in this area. Furthermore, although increased microbial diversity has previously been linked with health, our observation of higher microbial diversity being associated with increased proteolytic activity indicates that it may confer deleterious as well as beneficial effects on the host.

The influence of rosuvastatin on the gastrointestinal microbiota and host gene expression profiles

Statins are the most widely prescribed medications worldwide for the treatment of hypercholesterolemia. They inhibit the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-R), an enzyme involved in cholesterol synthesis in higher organisms and in isoprenoid biosynthesis in some bacteria. We hypothesized that statins may influence the microbial community in the gut through either direct inhibition or indirect mechanisms involving alterations to host responses. We therefore examined the impact of rosuvastatin (RSV) on the community structure of the murine gastrointestinal microbiota. RSV was orally administered to mice and the effects on the gut microbiota, host bile acid profiles, and markers of inflammation were analyzed. RSV significantly influenced the microbial community in both the cecum and feces, causing a significant decrease in α-diversity in the cecum and resulting in a reduction of several physiologically relevant bacterial groups. RSV treatment of mice significantly affected bile acid metabolism and impacted expression of inflammatory markers known to influence microbial community structure (including RegIIIγ and Camp) in the gut. This study suggests that a commonly used statin (RSV) leads to an altered gut microbial composition in normal mice with attendant impacts on local gene expression profiles, a finding that should prompt further studies to investigate the implications of statins for gut microbiota stability and health in humans.NEW & NOTEWORTHY This work demonstrates that rosuvastatin administration in mice affects the gastrointestinal microbiota, influences bile acid metabolism, and alters transcription of genes encoding factors involved in gut homeostasis and immunity in the gastrointestinal tract.

The altered gut microbiota in adults with cystic fibrosis

BACKGROUND

Cystic Fibrosis (CF) is an autosomal recessive disease that affects the function of a number of organs, principally the lungs, but also the gastrointestinal tract. The manifestations of cystic fibrosis transmembrane conductance regulator (CFTR) dysfunction in the gastrointestinal tract, as well as frequent antibiotic exposure, undoubtedly disrupts the gut microbiota. To analyse the effects of CF and its management on the microbiome, we compared the gut microbiota of 43 individuals with CF during a period of stability, to that of 69 non-CF controls using 454-pyrosequencing of the 16S rRNA gene. The impact of clinical parameters, including antibiotic therapy, on the results was also assessed.

RESULTS

The CF-associated microbiome had reduced microbial diversity, an increase in Firmicutes and a reduction in Bacteroidetes compared to the non-CF controls. While the greatest number of differences in taxonomic abundances of the intestinal microbiota was observed between individuals with CF and the healthy controls, gut microbiota differences were also reported between people with CF when grouped by clinical parameters including % predicted FEV₁ (measure of lung dysfunction) and the number of intravenous (IV) antibiotic courses in the previous 12 months. Notably, CF individuals presenting with severe lung dysfunction (% predicted FEV₁ ≤ 40%) had significantly (p < 0.05) reduced gut microbiota diversity relative to those presenting with mild or moderate dysfunction. A significant negative correlation (-0.383, Simpson's Diversity Index) was also observed between the number of IV antibiotic courses and gut microbiota diversity.

CONCLUSIONS

This is one of the largest single-centre studies on gut microbiota in stable adults with CF and demonstrates the significantly altered gut microbiota, including reduced microbial diversity seen in CF patients compared to healthy controls. The data show the impact that CF and it's management have on gut microbiota, presenting the opportunity to develop CF specific probiotics to minimise microbiota alterations.

Abstract P1-09-18: A clinically validated DNA microarray for high-resolution HER2 testing defines a new genomic subtype in high-risk breast cancer with equivocal results by IHC and FISH

Background: In all stages of breast cancer, the HER2 status of a patient's tumor is critically important as both a prognostic indicator, and for predicting response to targeted anti-HER2 therapies. CAP/ASCO 2013 guidelines recommend that newly diagnosed, recurrent, and metastatic breast tumors be evaluated for HER2 positivity by protein-based immunohistochemistry (IHC) and/or chromosome-based fluorescence in situ hybridization (FISH). In the majority of cases, these testing modalities provide a clearly actionable “positive” or “negative” answer. However, in an estimated 10- to 20% of breast cancers, both tests are reported as “equivocal” leaving the clinician with a treatment decision dilemma and no definitive alternative testing method. Here we report validation of an IHC-targeted DNA microarray comparative genomic hybridization (array CGH) assay for HER2 equivocal breast cancer, and definition of a new genomic subtype of HER2 status in high-risk breast cancer with equivocal IHC and FISH results.

Methods: IHC-targeted HER2 receptor “hot spot” DNA samples extracted from 25 formalin fixed paraffin embedded (FFPE) breast tumor tissue samples previously characterized by IHC and FISH, were analyzed by array CGH. Eight tumors were known to be highly HER2 positive, seven tumors had IHC scores of 0 with negative FISH, and ten tumors had HER2 receptor staining by IHC (1-2+) and equivocal results by FISH (4-6 HER2 gene copies.) Tumor DNA (test) and human genomic DNA (reference) were fluorescently labeled, and competitively hybridized to a custom-designed genomic DNA microarray with high-density probe coverage of the HER2 amplicon on chromosome 17 (Agilent Technologies, Santa Clara CA). The array design includes over 4,600 chromosome 17 probes representing the p arm, q arm, telomeric and centromeric regions with 66 tiling probes over the HER2 (ERBB2) gene. Following hybridization, average HER2 gene copy number was calculated for each tumor sample by converting mean log2 signal intensity ratio value into genomic region copy number adjusted for % clonal fraction and experimentally established log2 ratio compression of the assay.

Results: 25/25 (100%) of samples yielded adequate DNA for analysis and all highly HER2 positive and HER2 negative results were confirmed by array CGH. In 10/10 IHC equivocal cases with HER2 gene copy number 4-6 by FISH, CGH results confirmed HER2-Low gene copy number.

Results for 25 Validation SamplesNumber of CasesIHC ScoreFISHCGH Copy NumberResult83+Positive&gt; 6HER2-Positive101-2+Equivocal4-6HER2-Low70Negative&lt; 6HER2-Negative

Conclusions: High-resolution HER2 testing by IHC-targeted DNA microarray analysis accurately classifies HER2 status in breast cancer and better defines the HER2-Low genomic subtype most often called “equivocal” by standard IHC and FISH testing. This subcategory is characterized at the protein level by IHC evidence of anti-HER2 therapy target receptor expression on the surface of the cells, and at the genomic level by HER2 gene copy number &lt; 6. Results of the NSABP-B47 clinical trial and further studies with larger numbers of HER2-Low patients are needed to determine if these patients benefit from anti-HER2 therapy.

Citation Format: Gunn S, Yaziji H, Sims C, Govender S, Moore M, Cotter P, Jones S. A clinically validated DNA microarray for high-resolution HER2 testing defines a new genomic subtype in high-risk breast cancer with equivocal results by IHC and FISH [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-09-18.

Abstract P5-03-10: Development of a novel HER2 testing strategy, using image-based cell-sorting to isolate pure cell populations from FFPE upstream of FISH

Fluorescent in Situ Hybridization (FISH) guidelines defined by American Society of Clinical Oncology (ASCO) and the College of American Pathologists for determining HER2 status are set to improve accuracy and usefulness as a diagnostic marker in breast cancer. Despite these guidelines, many factors can influence HER2 testing results such as sample preparation, assay-conditions and interpretation of test results due to heterogeneous breast cancer samples. In this multi-site study, sample preparation was carried out using the DEPArray™ to recover pure tumor cell populations from formalin-fixed, paraffin-embedded (FFPE) breast tumor samples. We then compared HER2/CEP17 ratios obtained from the DEPArray™ processed samples from each laboratory to routine FISH on tissue sections.

Methods: Eight breast FFPE tumor tissue biopsies were obtained from commercial tissue banks. From the paraffin tissue blocks, four consecutive tissue curls (each 50 microns thick) were prepared. One curl from each of the 8 patient samples was distributed to four different laboratories for analysis following DEPArray™ based sample preparation. After an initial disassociation of each curl into a single-cell suspension, intact cells were sorted and then recovered based on cytokeratin/ vimentin/DAPI staining using the DEPArray™. Cytokeratin+/Vimentin-/DAPI+ tumor (~250) and Cytokeratin-/Vimentin+/DAPI+ stromal (~250) recovered cells were then deposited onto glass slides prior to standard dual-color HER2/CEP17 FISH analysis for comparison to conventional HER2 FISH result.

Results: Serially sectioned breast tumors from 8 negative/positive cases: 7 infiltrating ductal carcinoma (IDC) and 1 metastatic carcinoma were studied. All four sites demonstrated 100% concordance between FISH results compared to the conventional HER2 FISH result. Overall, &gt;60% of DEPArray™ isolated cells were recovered from FFPE samples that ranged from 1- 15 years of age and reported to contain 60% to 80% tumor content. The use of pure sorted cells permitted the accurate determination of HER2 amplification status in only the tumor cells while the stromal cells consistently yielded a more normalized ratio of HER2 to centromere 17.

Conclusion: The preliminary results of this multi-site study demonstrate that use of DEPArray™ for sorted pure populations is reproducible as well as reliable method for subsequent analysis of HER2 by FISH on FFPE derived tumor cells. Given that traditional FFPE-based HER2 FISH results may be influenced by the tissue sectioning procedure, tissue heterogeneity and/or the scattering of few HER2 amplified tumor cells among normal stromal cells. The DEPArray™ allows analysis of immunofluorescence images and DNA content to isolate and recover pure and intact cell populations. This isolation of pure cell populations prior to FISH analysis is attractive for achieving precise determination of HER2 status on equivocal cases. A more formal analytical validation of this approach through CLIA is currently underway.

Citation Format: Gerber A, Konig L, Millner L, Strotoman L, Khurana A, Kasimir-Bauer S, Moore MW, Cotter PD, Bischoff F. Development of a novel HER2 testing strategy, using image-based cell-sorting to isolate pure cell populations from FFPE upstream of FISH [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-03-10.

Influence of GABA and GABA-producing Lactobacillus brevis DPC 6108 on the development of diabetes in a streptozotocin rat model

The aim of this study was to investigate if dietary administration of γ-aminobutyric acid (GABA)-producing Lactobacillus brevis DPC 6108 and pure GABA exert protective effects against the development of diabetes in streptozotocin (STZ)-induced diabetic Sprague Dawley rats. In a first experiment, healthy rats were divided in 3 groups (n=10/group) receiving placebo, 2.6 mg/kg body weight (bw) pure GABA or L. brevis DPC 6108 (~10(9)microorganisms). In a second experiment, rats (n=15/group) were randomised to five groups and four of these received an injection of STZ to induce type 1 diabetes. Diabetic and non-diabetic controls received placebo [4% (w/v) yeast extract in dH2O], while the other three diabetic groups received one of the following dietary supplements: 2.6 mg/kg bw GABA (low GABA), 200 mg/kg bw GABA (high GABA) or ~10(9) L. brevis DPC 6108. L. brevis DPC 6108 supplementation was associated with increased serum insulin levels (P<0.05), but did not alter other metabolic markers in healthy rats. Diabetes induced by STZ injection decreased body weight (P<0.05), increased intestinal length (P<0.05) and stimulated water and food intake. Insulin was decreased (P<0.05), whereas glucose was increased (P<0.001) in all diabetic groups, compared with non-diabetic controls. A decrease (P<0.01) in glucose levels was observed in diabetic rats receiving L. brevis DPC 6108, compared with diabetic-controls. Both the composition and diversity of the intestinal microbiota were affected by diabetes. Microbial diversity in diabetic rats supplemented with low GABA was not reduced (P>0.05), compared with non-diabetic controls while all other diabetic groups displayed reduced diversity (P<0.05). L. brevis DPC 6108 attenuated hyperglycaemia induced by diabetes but additional studies are needed to understand the mechanisms involved in this reduction.

Dietary threonine response of Pekin ducks from hatch to 14 d of age based on performance, serology, and intestinal mucin secretion

Two experiments were conducted to determine the dietary threonine (Thr) requirement of Pekin ducks from hatch to 14 d of age. In experiment 1, practical corn-soybean meal diets were formulated to contain 0.78, 0.84, 0.90, 0.96, and 1.02% Thr (0.74, 0.83, 0.88, 0.92, and 1.00% Thr on an analyzed basis). In experiment 2, corn-soybean meal diets supplemented with 11 crystalline amino acids were formulated to contain 0.60, 0.70, 0.80, 0.90, 1.00, and 1.10% Thr (0.60, 0.75, 0.89, 0.95, 1.01, and 1.09% Thr on an analyzed basis). In both experiments, diets were fed to 8 replicate cages with 6 male ducks per cage. Body weight and feed intake from each cage were recorded weekly. At 14 d of age, breast meat, ileal digesta, and serum were collected to determine breast meat yield, mucin secretion, and serology parameters. In both studies, the estimated Thr requirement (expressed as % dietary Thr basis) for 14 d BW and BW gain (BWG) by quadratic broken-line (QBL) regression were similar, which were 0.87 and 0.86%, respectively. Additional measures in both experiments resulted in Thr requirements via QBL regression in rank order of crude mucin secretion < breast meat yield < serum immune activity. Summing up the estimates from both studies, the Thr requirement ranged from a low of 0.81% to maximize feed intake (FI) to a high of 1.00% to maximize serum Rb L100 by QBL regression. Correspondingly, the Thr requirement varied between a low of 0.90% to maximize crude mucin secretion on a dry matter intake (DMI) basis and a high of 0.98% to maximize feed-to-gain when using quadratic regression.

Spatial variation of the colonic microbiota in patients with ulcerative colitis and control volunteers

OBJECTIVES

The relevance of spatial composition in the microbial changes associated with UC is unclear. We coupled luminal brush samples, mucosal biopsies and laser capture microdissection with deep sequencing of the gut microbiota to develop an integrated spatial assessment of the microbial community in controls and UC.

DESIGN

A total of 98 samples were sequenced to a mean depth of 31,642 reads from nine individuals, four control volunteers undergoing routine colonoscopy and five patients undergoing surgical colectomy for medically-refractory UC. Samples were retrieved at four colorectal locations, incorporating the luminal microbiota, mucus gel layer and whole mucosal biopsies.

RESULTS

Interpersonal variability accounted for approximately half of the total variance. Surprisingly, within individuals, asymmetric Eigenvector map analysis demonstrated differentiation between the luminal and mucus gel microbiota, in both controls and UC, with no differentiation between colorectal regions. At a taxonomic level, differentiation was evident between both cohorts, as well as between the luminal and mucosal compartments, with a small group of taxa uniquely discriminating the luminal and mucosal microbiota in colitis. There was no correlation between regional inflammation and a breakdown in this spatial differentiation or bacterial diversity.

CONCLUSIONS

Our study demonstrates a conserved spatial structure to the colonic microbiota, differentiating the luminal and mucosal communities, within the context of marked interpersonal variability. While elements of this structure overlap between UC and control volunteers, there are differences between the two groups, both in terms of the overall taxonomic composition and how spatial structure is ascribable to distinct taxa.

Victimisation and psychosocial difficulties associated with sexual orientation concerns: a school-based study of adolescents

This study examined victimisation, substance misuse, relationships, sexual activity, mental health difficulties and suicidal behaviour among adolescents with sexual orientation concerns in comparison to those without such concerns. 1112 Irish students (mean age 14 yrs) in 17 mixed-gender secondary schools completed a self-report questionnaire with standardised scales and measures of psychosocial difficulties. 58 students (5%) reported having concerns regarding their sexual orientation. Compared with their peers, they had higher levels of mental health difficulties and a markedly-increased prevalence of attempted suicide (29% vs. 2%), physical assault (40% vs. 8%), sexual assault (16%vs. 1%) and substance misuse. Almost all those (90%) with sexual orientation concerns reported having had sex compared to just 4% of their peers. These results highlight the significant difficulties associated with sexual orientation concerns in adolescents in Ireland. Early and targeted interventions are essential to address their needs.

Antipsychotics and the gut microbiome: olanzapine-induced metabolic dysfunction is attenuated by antibiotic administration in the rat

The atypical antipsychotic olanzapine is often associated with serious metabolic side effects including weight gain and increased visceral fat. These adverse events are a considerable clinical problem and the mechanisms underlying them are multifactorial and poorly understood. Growing evidence suggests that the gut microbiota has a key role in energy regulation and disease states such as obesity. Moreover, we recently showed that chronic olanzapine altered the composition of the gut microbiome in the rat. It is thus possible that treatments that alter gut microbiota composition could ameliorate olanzapine-induced weight gain and associated metabolic syndrome. To this end, we investigated the impact of antibiotic-induced alteration of the gut microbiota on the metabolic effects associated with chronic olanzapine treatment in female rats. Animals received vehicle or olanzapine (2 mg kg(-1) per day) for 21 days, intraperitoneal injection, two times daily. Animals were also coadministered vehicle or an antibiotic cocktail consisting of neomycin (250 mg kg(-1) per day), metronidazole (50 mg kg(-1) per day) and polymyxin B (9 mg kg(-1) per day) by oral gavage, daily, beginning 5 days before olanzapine treatment. The antibiotic cocktail drastically altered the microbiota of olanzapine-treated rats, and olanzapine alone was also associated with an altered microbiota. Coadministration of the antibiotic cocktail in olanzapine-treated rats attenuated: body weight gain, uterine fat deposition, macrophage infiltration of adipose tissue, plasma free fatty acid levels, all of which were increased by olanzapine alone. These results suggest that the gut microbiome has a role in the cycle of metabolic dysfunction associated with olanzapine, and could represent a novel therapeutic target for preventing antipsychotic-induced metabolic disease.

P1-07-13: Efficiency of a Laboratory Developed HER2 FISH Test on Circulating Tumor Cells

INTRODUCTION: Most circulating tumor cell (CTC) platforms rely on EpCAM for capture and cytokeratin (CK) for detection. However, an important population of cells that are CK-negative (i.e. cells with epithelial-mesenchymal transition (EMT) phenotype) will be missed. We report a new strategy to efficiently isolate a more heterogeneous population of CTCs using an antibody cocktail.

METHODS: In the first prospective study, blood (20 mL) was collected from 89 patients diagnosed with various late stage metastatic/recurrent cancers (breast, CRC, lung, prostate) following IRB approval. PBMCs were incubated with either EpCAM alone or a mixture of 10 capture antibodies to target both epithelial and mesenchymal cells. CTCs were subsequently captured in the OncoCEE™ channels and detected with cytokeratin (CK) and CD45. A second prospective IRB approved study involving 54 patients diagnosed with late stage metastatic/recurrent breast cancer was performed using similar detection strategies (CK cocktail mixture and anti-CD45) with the addition of HER2 FISH to determine amplification status among captured CK+/CD45- and CK-/CD45-cells.

RESULTS: In the first study, overall detection of CK+ cells was 83% with EpCAM alone and 93% with antibody cocktail. In addition, a median of 0.4 CK+ cells/mL and 1.0 CK+ cells/mL was observed using EpCAM and antibody cocktail, respectively. In the second study, CK+/CD45- cells were detected in 43 of 54 cases (80%). Among the 43 cases in which CK+/CD45- cells were detected, high concordance (93%) in HER2 status between primary tumor and CTCs was observed with HER2 amplification noted in both CK+/CD45- (50%) and CK-/CD45- (50%) cells.

CONCLUSIONS: We have developed a novel and robust method for CTC enumeration that utilizes a cocktail of antibodies for the detection of a heterogeneous (CK+ and CK-) population of CTCs. Our findings suggest an important population of CK- cells is being missed by current stain criteria in breast cancer patients. Data also demonstrate that recovery of CTCs from peripheral blood using the OncoCEE™ platform is efficient and suitable for FISH-based laboratory testing.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-13.

Impact of the broad-spectrum antimicrobial peptide, lacticin 3147, on Streptococcus mutans growing in a biofilm and in human saliva

AIMS

To evaluate the ability of the broad-spectrum lantibiotic, lacticin 3147, to prevent Streptococcus mutans biofilm formation and disrupt existing biofilms.

METHODS AND RESULTS

Minimum inhibitory concentrations (MIC) and minimum biofilm inhibitory concentrations of purified lacticin 3147 were determined using a microdilution method. Lacticin 3147 effectively inhibited planktonic Strep. mutans, with MIC of 1.9-3.8 μmol l(-1). Time-kill kinetic studies confirmed that lacticin 3147 exhibited bactericidal activity against Strep. mutans at 38 μmol l(-1) (or 10× MIC). The effect of lacticin 3147 on biofilm formation and reduction was also determined. Exposure to 6.3-μmol l(-1) lacticin 3147 (2× MIC) resulted in substantial reductions in Strep. mutans biofilm formation while lacticin 3147 was less effective against 1-day-old biofilms. Culture-based analyses revealed that lacticin 3147 (50 μmol l(-1)) significantly inhibited Streptococcus spp. present in human saliva (P < 0.05) with an approximate 4-log reduction in viability compared with the control.

CONCLUSIONS

These results indicate that lacticin 3147 may be an effective therapy against Strep. mutans and was shown to substantially attenuate its ability to form a biofilm.

SIGNIFICANCE AND IMPACT OF THE STUDY

Lacticin 3147 has the potential to be a useful adjunct to traditional oral therapeutic approaches in addition to its use as a bioactive ingredient for food applications.

Mechanisms of donor-specific tolerance in recipients of haploidentical combined bone marrow/kidney transplantation

We recently reported long-term organ allograft survival without ongoing immunosuppression in four of five patients receiving combined kidney and bone marrow transplantation from haploidentical donors following nonmyeloablative conditioning. In vitro assays up to 18 months revealed donor-specific unresponsiveness. We now demonstrate that T cell recovery is gradual and is characterized by memory-type cell predominance and an increased proportion of CD4⁺ CD25⁺ CD127⁻ FOXP3⁺ Treg during the lymphopenic period. Complete donor-specific unresponsiveness in proliferative and cytotoxic assays, and in limiting dilution analyses of IL-2-producing and cytotoxic cells, developed and persisted for the 3-year follow-up in all patients, and extended to donor renal tubular epithelial cells. Assays in two of four patients were consistent with a role for a suppressive tolerance mechanism at 6 months to 1 year, but later (≥ 18 months) studies on all four patients provided no evidence for a suppressive mechanism. Our studies demonstrate, for the first time, long-term, systemic donor-specific unresponsiveness in patients with HLA-mismatched allograft tolerance. While regulatory cells may play an early role, long-term tolerance appears to be maintained by a deletion or anergy mechanism.

The impact of nisin on sensitive and resistant mutants of Listeria monocytogenes in cottage cheese

AIMS

Listeria monocytogenes ΔgadD1 and ΔlisK mutants display enhanced and reduced sensitivity, respectively, to the food preservative nisin in laboratory media. However, the behaviour of these strains in a nisin-containing food has not been assessed. Here we use cottage cheese as a model food to address this issue.

MATERIALS AND RESULTS

Antibiotic-resistant forms of the wild-type and mutant strains were employed to investigate the behaviour of multiple strains in a single food sample, thereby eliminating the problem of intersample variation. Using this approach, it was established that percentage survival of the ΔlisK mutant was greater than the parent strain in the absence of nisin and that this relative difference became even more dramatic in cottage cheese supplemented with nisin. The numbers of the ΔgadD1 mutant decreased more rapidly than the parent in cottage cheese without nisin, but surprisingly this trend was reversed in nisin-supplemented cheese. Upon the addition of 10 mmol l(-1) monosodium glutamate, a substrate for the glutamate decarboxylase (GAD) system, the wild-type LO28 strain regained its relative advantage over ΔgadD1.

CONCLUSIONS

Care needs to be taken when predicting the behaviour of mutants of L. monocytogenes with altered resistance to nisin in food as experiments in laboratory media are not always a good indicator of how the strains will behave in such food environments.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study further emphasizes the importance of utilizing food matrices to confirm observations made using laboratory media.

Composition and energy harvesting capacity of the gut microbiota: relationship to diet, obesity and time in mouse models

BACKGROUND AND AIMS

Increased efficiency of energy harvest, due to alterations in the gut microbiota (increased Firmicutes and decreased Bacteroidetes), has been implicated in obesity in mice and humans. However, a causal relationship is unproven and contributory variables include diet, genetics and age. Therefore, we explored the effect of a high-fat (HF) diet and genetically determined obesity (ob/ob) for changes in microbiota and energy harvesting capacity over time.

METHODS

Seven-week-old male ob/ob mice were fed a low-fat diet and wild-type mice were fed either a low-fat diet or a HF-diet for 8 weeks (n=8/group). They were assessed at 7, 11 and 15 weeks of age for: fat and lean body mass (by NMR); faecal and caecal short-chain fatty acids (SCFA, by gas chromatography); faecal energy content (by bomb calorimetry) and microbial composition (by metagenomic pyrosequencing).

RESULTS

A progressive increase in Firmicutes was confirmed in both HF-fed and ob/ob mice reaching statistical significance in the former, but this phylum was unchanged over time in the lean controls. Reductions in Bacteroidetes were also found in ob/ob mice. However, changes in the microbiota were dissociated from markers of energy harvest. Thus, although the faecal energy in the ob/ob mice was significantly decreased at 7 weeks, and caecal SCFA increased, these did not persist and faecal acetate diminished over time in both ob/ob and HF-fed mice, but not in lean controls. Furthermore, the proportion of the major phyla did not correlate with energy harvest markers.

CONCLUSION

The relationship between the microbial composition and energy harvesting capacity is more complex than previously considered. While compositional changes in the faecal microbiota were confirmed, this was primarily a feature of high-fat feeding rather than genetically induced obesity. In addition, changes in the proportions of the major phyla were unrelated to markers of energy harvest which changed over time. The possibility of microbial adaptation to diet and time should be considered in future studies.

ARHGEF9 disruption in a female patient is associated with X linked mental retardation and sensory hyperarousal

We identified a female patient with mental retardation and sensory hyperarousal. She has a de novo paracentric inversion of one X chromosome with completely skewed inactivation of the normal X chromosome. We aimed to identify whether a single gene or gene region caused her cognitive and behavioural impairment and that of others. Fluorescent in situ hybridisation (FISH) showed that the centromeric breakpoint disrupts a single gene: ARHGEF9 (CDC42 guanine nucleotide exchange factor (GEF) 9). We also found that the levels of the ARHGEF9 transcript from the patient are 10-fold less than those found in control samples. ARHGEF9 encodes a RhoGEF family protein: collybistin (hPEM), which is highly expressed in the brain. Collybistin can regulate actin cytoskeletal dynamics and may also modulate GABAergic and glycinergic neurotransmission through binding of a scaffolding protein, gephyrin, at the synapse. This potential dual role may explain both the mental retardation and hyperarousal observed in our patient.

The glutamate decarboxylase acid resistance mechanism affects survival of Listeria monocytogenes LO28 in modified atmosphere-packaged foods

AIMS

The contribution of the glutamate decarboxylase (GAD) acid resistance system to survival and growth of Listeria monocytogenes LO28 in modified atmosphere-packaged foods was examined.

METHODS AND RESULTS

The survival and growth of the wild-type LO28 and four GAD deletion mutants (DeltagadA, DeltagadB, DeltagadC, DeltagadAB) in packaged foods (minced beef, lettuce, dry coleslaw mix) during storage at 4, 8 and 15 degrees C were studied. Survival and growth patterns varied with strain, product type, gas atmosphere and storage temperature. In minced beef, the wild-type LO28 survived better (P < 0.05) than the GAD mutant strains at 8 and 15 degrees C. In both packaged vegetables at all storage temperatures, the wild-type strain survived better (P < 0.05) than the double mutant DeltagadAB. The requirement for the individual gad genes varied depending on the packaged food. In the case of lettuce, gadA played the most important role, while the gadB and gadC genes played the greatest role in packaged coleslaw (at 15 degrees C).

CONCLUSIONS

This work demonstrates that elements of the GAD system play significant roles in survival of L. monocytogenes LO28 during storage in modified atmosphere-packaged foods.

SIGNIFICANCE AND IMPACT OF THE STUDY

A better understanding of how L. monocytogenes behaves in modified atmosphere-packaged foods, and how it responds to elevated carbon dioxide atmospheres.

Controlling Listeria monocytogenes in Cottage cheese through heterologous production of enterocin A by Lactococcus lactis

AIMS

Enterocin A is an example of a class IIa bacteriocin with potent anti-listerial activity. This study was initiated with a view to harnessing this activity, through heterologous production by a lactococcal starter strain, to limit levels of Listeria monocytogenes in a food (Cottage cheese).

METHODS AND RESULTS

Plasmid pEnt02 (containing entA, I, T and D genes under the control of a constitutive promoter) was introduced into a Lactococcus lactis strain capable of fermenting lactose. When this bacteriocin-producing starter was used in combination with a non-enterocin A producer, thereby compensating for an associated reduction in acid production, during a Cottage cheese fermentation, a decrease in L. monocytogenes (tagged with lux genes for convenience) levels was evident.

CONCLUSIONS

Enterocin A, heterologously produced by a food grade lactic acid bacteria (LAB), was therefore shown to have potential for use as a biocontrol agent in food.

SIGNIFICANCE AND IMPACT OF THE STUDY

Many of the most active anti-listerial compounds identified to date are enterocins. However, because of Enterococcus-associated concerns, the use of these antimicrobials in a food setting has been curtailed. Although enterocins have been heterologously produced in LAB to overcome this problem, this study represents the first occasion upon which the benefits of such heterologous production have been demonstrated in a food context.

ARHGEF9 disruption in a female patient is associated with X linked mental retardation and sensory hyperarousal

INTRODUCTION

We identified a female patient with mental retardation and sensory hyperarousal. She has a de novo paracentric inversion of one X chromosome with completely skewed inactivation of the normal X chromosome.

OBJECTIVE

We aimed to identify whether a single gene or gene region caused her cognitive and behavioural impairment and that of others.

RESULTS

Fluorescent in situ hybridisation (FISH) showed that the centromeric breakpoint disrupts a single gene: ARHGEF9 (CDC42 guanine nucleotide exchange factor (GEF) 9). The telomeric break lies in a gene poor region. We also found that the levels of the ARHGEF9 transcript from the patient are 10-fold less than those found in control samples. Consequently, we sequenced the coding exons and intron/exon borders of the ARHGEF9 gene in 99 probands from families with X linked mental retardation (XLMR) and 477 mentally retarded males in whom a diagnosis of Fragile X syndrome had been excluded. We did not identify any pathogenic changes; however, we did identify intronic nucleotide changes that might alter splicing.

CONCLUSION

ARHGEF9 encodes a RhoGEF family protein: collybistin (hPEM), which is highly expressed in the developing and adult brain. Collybistin can regulate actin cytoskeletal dynamics and may also modulate GABAergic and glycinergic neurotransmission through binding of a scaffolding protein, gephyrin, at the synapse. This potential dual role may explain both the mental retardation and hyperarousal observed in our patient. While ARHGEF9 appears to be an uncommon cause of mental retardation in males, it should be considered in patients with mental retardation and sensory hyperarousal.

Interstitial deletions of chromosome 6q: genotype-phenotype correlation utilizing array CGH

Interstitial deletions of the long arm of chromosome 6 are relatively rare, with fewer than 100 cases reported. Phenotypic variation is in large part due to differences in size and location of the segmental aneuploidy. We report three new patients with interstitial deletions of chromosome 6q defined at the molecular level by array comparative genomic hybridization (array CGH). In two of three cases, the molecular breakpoints differed from those indicated by conventional karyotyping, demonstrating the enhanced resolution of array CGH. Two patients had minimal deletions of 6 and 8.8 Mb involving 6q16.2-->q21, and the third patient had a deletion of 11.3 Mb spanning 6q15-->q21. All three had developmental delay, craniofacial dysmorphology, and functional eye disorders, suggesting that genes affecting brain and craniofacial development are located in 6q16.2-->q21, the deleted region common to all three patients. Furthermore, gene(s) for discordant phenotypic features, such as central diabetes insipidus, may reside at 6q15, the monosomic region unique to patient 3. All three cases described here showed loss of paternal alleles within the deleted segment, providing further evidence of the predominantly paternal origin for 6q deletions and rearrangements.

Genomic microarray analysis identifies candidate loci in patients with corpus callosum anomalies

Absence of the corpus callosum is often associated with cognitive deficits, autism, and epilepsy. Using a genomic microarray, the authors analyzed DNA from 25 patients with radiographically confirmed callosal anomalies and identified three patients with de novo copy number changes in chromosome regions 2q37, 6qter, and 8p. Chromosomal deletions and duplications may be a relatively common cause of cerebral malformations.

Prader-Willi syndrome resulting from an unbalanced translocation: characterization by array comparative genomic hybridization

Prader-Willi syndrome (PWS) is caused by lack of expression of paternally inherited genes on chromosome 15q11-->15q13. Most cases result from microdeletions in proximal chromosome 15q. The remainder results from maternal uniparental disomy of chromosome 15, imprinting center defects, and rarely from balanced or unbalanced chromosome rearrangements involving chromosome 15. We report a patient with multiple congenital anomalies, including craniofacial dysmorphology, microcephaly, bilateral cryptorchidism, and developmental delay. Cytogenetic analysis showed a de novo 45,XY,der(5)t(5;15)(p15.2;q13), -15 karyotype. In effect, the proband had monosomies of 5p15.2-->pter and 15pter-->15q13. Methylation polymerase chain reaction analysis of the promoter region of the SNRPN gene showed only the maternal allele, consistent with the PWS phenotype. The proband's expanded phenotype was similar to other patients who have PWS as a result of unbalanced translocations and likely reflects the contribution of the associated monosomy. Array comparative genomic hybridization (array CGH) confirmed deletions of both distal 5p and proximal 15q and provided more accurate information as to the size of the deletions and the molecular breakpoints. This case illustrates the utility of array CGH in characterizing complex constitutional structural chromosome abnormalities at the molecular level.

Prenatal diagnosis of de novo X;autosome translocations

The identification of a de novo apparently balanced structural chromosome rearrangement at prenatal diagnosis can be problematic and raises unique genetic counseling issues. Two breakpoint rearrangements such as reciprocal translocations or inversions have a 6.7% empiric risk of phenotypic abnormality. Abnormal phenotypes are thought to result from gene disruption, position effect, or deletion at one of the breakpoints. Prenatal diagnosis of de novo X;autosome translocations is rare, and presents additional unique risks due to the effects of X-inactivation and the possibility of disruption of the single active copy of an X-linked gene. We report the identification of a de novo apparently balanced t(X;6)(q26;q23) ascertained after amniocentesis for advanced maternal age. The parents were counseled regarding the risk of a de novo apparently balanced translocation, including the potential risk of an X-linked Mendelian disorder resulting from disruption of a gene at the Xq26 breakpoint. While the normal X chromosome was late replicating in all metaphases, no conclusions from this data could be drawn as the X-inactivation ratio in amniocytes might not be representative of other tissues. The possibility of future premature ovarian failure was also noted due to the position of the breakpoint at Xq26, although no specific risk could be ascribed. The parents elected to continue the pregnancy, and at 17 months of age, the proband was phenotypically and developmentally normal. Long-term follow-up will be required to assess development delay and any fertility issues. Based on review of the few cases reported to date and excluding any risk for later reproductive abnormalities, we estimated the risk of phenotypic abnormality or developmental delay in a prenatally ascertained de novo X;autosome carrier to be as high as 50%. This case illustrates the complexities in counseling for prenatally ascertained de novo X;autosome translocations and the need for additional cases to be reported.

Epigenetic detection of human chromosome 14 uniparental disomy

The recent demonstration of genomic imprinting of DLK1 and MEG3 on human chromosome 14q32 indicates that these genes might contribute to the discordant phenotypes associated with uniparental disomy (UPD) of chromosome 14. Regulation of imprinted expression of DLK1 and MEG3 involves a differentially methylated region (DMR) that encompasses the MEG3 promoter. We exploited the normal differential methylation of the DLK1/MEG3 region to develop a rapid diagnostic PCR assay based upon an individual's epigenetic profile. We used methylation-specific multiplex PCR in a retrospective analysis to amplify divergent lengths of the methylated and unmethylated MEG3 DMR in a single reaction and accurately identified normal, maternal UPD14, and paternal UPD14 in bisulfite converted DNA samples. This approach, which is based solely on differential epigenetic profiles, may be generally applicable for rapidly and economically screening for other imprinting defects associated with uniparental disomy, determining loss of heterozygosity of imprinted tumor suppressor genes, and identifying gene-specific hypermethylation events associated with neoplastic progression.

Exclusion of PTPN11 mutations in Costello syndrome: further evidence for distinct genetic etiologies for Noonan, cardio-facio-cutaneous and Costello syndromes

Costello syndrome (CS) is a rare, multiple congenital anomaly syndrome with characteristic dysmorphic features, cardiac anomalies and a tendency to develop certain cancers. Phenotypically there is some overlap with other genetic disorders, notably cardio-facio-cutaneous (CFC) syndrome and Noonan syndrome (NS), suggesting that these syndromes may be allelic. We recently identified PTPN11, which encodes the non-receptor protein tyrosine phosphatase, SHP-2, as a major NS disease gene. In this report, we screened a cohort of 27 patients, with the clinical diagnosis of CS, for PTPN11 mutations using denaturing high performance liquid chromatography analysis. No mutations of the PTPN11 gene were found in the CS patients. Common polymorphisms in introns 6 and 7 and exon 8 were identified in four individuals. With our previous exclusion of PTPN11 mutations in CFC syndrome, these data suggest distinct genetic etiologies for Noonan, CFC and Costello syndromes.

Stabilization of a terminal inversion duplication of 8p by telomere capture from 18q

Terminal inversion duplications of the short arm of chromosome 8 are one of the more common chromosome rearrangements in humans. We report an infant with multiple congenital anomalies, in whom karyotype analysis showed a terminal inversion duplication of 8p including additional material at the distal end of the derivative chromosome, shown to be of chromosome 18q origin. Terminal inversion duplications of 8p are the result of meiotic recombination between inverted olfactory gene receptor repeats in 8p. This recombination generates a dicentric intermediate that breaks during anaphase, and the broken chromosome end is stabilized by telomere healing or telomere capture. The origin of the telomeric region in the majority of constitutional chromosome deletions studied to date was shown to be from telomere healing; the de novo addition of telomeric repeats. In the proband a cytogenetically detectable piece of chromosome 18q was present on the distal end of the derivative 8, suggesting that this chromosome was stabilized by telomere capture of 18q. FISH analyses of additional cases may yield information as to whether telomere capture or telomere-healing events are the predominant mechanism of chromosome stabilization in terminal inversion duplications of 8p.

Periventricular heterotopia associated with chromosome 5p anomalies

Periventricular heterotopia (PH) is characterized by neuronal nodules along the lateral ventricles. Whereas mutations in X-linked FLNA cause such cortical malformations, the authors report two cases of PH localizing to chromosome 5p. Both subjects have complex partial seizures. MRI demonstrated bilateral nodular PH, with subcortical heterotopia or focal gliosis. FISH identified a duplication of 5p15.1 [46,XX,dup(5)(p15.1p15.1)] and a trisomy of 5p15.33 [46,XY,der(14)t(5;14)(p15.33;p11.2) mat]. These findings suggest a new PH locus along the telomeric end of chromosome 5p.

Tandem duplication mosaicism: characterization of a mosaic dup(5q) and review

Mosaicism for tandem duplications is rare. Most patients reported had abnormal phenotypes of varying severity, depending on the chromosomal imbalance involved and the level of mosaicism. Post-zygotic unequal sister-chromatid exchange has been proposed as the main mechanism for tandem duplication mosaicism. However, previous molecular analyses have implicated both meiotic and post-zygotic origins for the duplication. We describe a newborn male who was originally diagnosed in utero with arrhythmia and tetralogy of Fallot. He had multiple dysmorphic features including telecanthus, blepharophimosis, high broad nasal bridge with a square-shaped nose, flat philtrum, thin upper lip, down-turned corners of the mouth, high-arched palate, micrognathia, asymmetric ears, and long, thin fingers and toes. Karyotyping of peripheral blood lymphocytes showed mosaicism for a tandem duplication of part of the long arm of one chromosome 5: mos46,XY,dup(5)(q13q33)[6]/46,XY[45]. Fibroblast cultures had the same mosaic karyotype with a higher frequency of the dup(5) clone: mos46,XY,dup(5)(q13q33)[9]/46,XY[21]. Fluorescence in situ hybridization analysis with a wcp5 confirmed the chromosome 5 origin of the additional material. Parental karyotypes were normal indicating a de novo origin of the dup(5) in the proband. Molecular analyses of chromosome 5 sequence-tagged-site (STS) markers in our family were consistent with a post-zygotic origin for the duplication. Therefore, mosaicism for tandem duplications can arise both through meiotic or mitotic errors, as a result of unequal crossing over or unequal sister-chromatid exchange, respectively. Our review indicates that mosaicism for tandem duplications is likely under-ascertained and that parental karyotyping of probands with non-mosaic tandem duplications should be performed.

Minute supernumerary marker chromosomes identified in two patients with a related, larger pseudodicentric chromosome

We describe two cases in which a minute supernumerary marker chromosome (SMC) was identified in addition to a larger pseudodicentric chromosome. Case 1, a phenotypically normal male, had mosaicism for a psu dic(15;15)(q11.2;q11.2) chromosome and a minute SMC. Fluorescence in situ hybridization (FISH) showed that the minute SMC was D15Z1 positive, indicating a chromosome 15 origin. Case 2 was a 22-week fetus with mosaicism for a normal and two abnormal cell lines: one had a psu dic (22;22)(q11.2;q11.2) chromosome containing euchromatin, usually associated with cat eye syndrome; the other a minute SMC. The minute SMC was positive with the D14Z1/D22Z1 alpha-satellite probe, indicating a chromosome 14 or chromosome 22 origin. Deletion of centromeric material was proposed as one mechanism of centromere inactivation in dicentric chromosomes. The origin of these two minute SMC suggests that they were derived from one of the centromeres of the larger pseudodicentric chromosome. These stable minute SMC may be the by-product of a deletion event inactivating one centromere of a dicentric chromosome to generate a pseudodicentric chromosome. Alternatively, the minute SMC may originate from further rearrangement of the larger pseudodicentric chromosome. These cases suggest possible mechanisms for the origin of minute SMC.

Role of the glutamate decarboxylase acid resistance system in the survival of Listeria monocytogenes LO28 in low pH foods

The glutamate decarboxylase (GAD) acid resistance system of the foodborne pathogen Listeria monocytogenes plays a major role in its survival at low pH. It was found that survival of the wild-type strain. LO28, in acidified reconstituted skim milk, diluted to reduce free glutamate levels. improves in response to supplementation with monosodium glutamate. A mutant, in which the two listerial GAD homologs have been deleted (and in which there is no discernible GAD activity), did not respond to glutamate supplementation and displayed greatly enhanced sensitivity in a number of low pH foods, even when levels of free glutamate were as low as 0.22 mM. We thus show that the GAD system plays a major role in the survival of L. monocytogenes in acidic foods even when levels of free glutamate are low.

Loss of subtelomeric sequence associated with a terminal inversion duplication of the short arm of chromosome 4

We report on a 4(1/2)-year-old girl, who presented with multiple minor anomalies consistent with trisomy for 4p. GTG-banding identified a de novo terminal inversion duplication of distal 4p, dup(4)(p16.3p15.3). Fluorescence in situ hybridization (FISH) with a wcp4 probe confirmed the chromosome 4 origin of the additional material. FISH with a 4p subtelomere probe, D4F26, showed no signal on the dup(4) chromosome identifying a deletion of this region. Molecular analysis of 4p STS loci confirmed the subtelomeric deletion and showed loss of the paternal allele in this region. The paternal origin of the deleted region and homozygosity for one of the two paternal alleles within the region of the duplication suggests that a sister chromatid rearrangement on the paternal chromosome 4 was involved in the formation of the dup(4) chromosome. To date, the best characterized mechanisms of formation of chromosome duplications are terminal inversion duplications of 8p, which were shown to be derived from rearrangements at maternal meiosis-I. Our data show that mechanisms other than a maternal meiosis-I rearrangement can lead to the formation of terminal inversion duplications. FISH analysis with the appropriate subtelomeric probes is warranted in terminal inversion duplications to check for associated deletions.

Characterization of a long-term survivor with Stüve-Wiedemann syndrome and mosaicism of a supernumerary marker chromosome

Stüve-Wiedemann syndrome (SWS) is typically lethal in the neonatal period; only two patients have been reported with a longer survival. We report a new patient with SWS, who at 9 years of age is one of the longest survivors with this disorder. In addition to the characteristic features of SWS, she has a number of unique clinical signs, including lack of corneal and patellar reflexes, a smooth tongue with no fungiform papillae, chronic gingival abscesses, mottled, poor dentition, blotchy pigmentation of the skin, unusual infections, multiple fractures, and progressive scoliosis. Cytogenetic analysis identified mosaicism for a supernumerary marker chromosome (SMC), seen in the majority of amniocytes, blood, and skin fibroblasts. The SMC was shown to be derived from chromosome 5 and contains euchromatin. The significance of the SMC to the etiology of SWS is unknown. This patient further demonstrates that SWS is not universally lethal.

Inherited duplication of Xq27.2-->qter: phenocopy of infantile Prader-Willi syndrome

A male is described with familial duplication of the distal long arm of the X chromosome (Xq27.2-->qter) at the distal short arm (Xp22.3). The proband has features of the male Prada-Willi syndrome phenotype that have not previously been reported in other males with duplication of Xq27-->qter.