Biclustering of adverse drug events in the FDA's spontaneous reporting system

In this article, we present a new pharmacovigilance data mining technique based on the biclustering paradigm, which is designed to identify drug groups that share a common set of adverse events (AEs) in the spontaneous reporting system (SRS) of the US Food and Drug Administration (FDA). A taxonomy of biclusters is developed, revealing that a significant number of bona fide adverse drug event (ADE) biclusters have been identified. Statistical tests indicate that it is extremely unlikely that the bicluster structures thus discovered, as well as their content, could have arisen by mere chance. Some of the biclusters classified as indeterminate provide support for previously unrecognized and potentially novel ADEs. In addition, we demonstrate the potential importance of the proposed methodology in several important aspects of pharmacovigilance such as providing insight into the etiology of ADEs, facilitating the identification of novel ADEs, suggesting methods and a rationale for aggregating terminologies, highlighting areas of focus, and providing an exploratory tool for data mining.

Prevalence of psychotropic medication use among cosmetic and medical dermatology patients: a comparative study

BACKGROUND

Little is known about the psychologic status of cosmetically oriented dermatology patients.

OBJECTIVE

We sought to determine the prevalence of psychotropic medication use among such patients to offer insight into the rates of psychopathology in this group.

METHODS

We conducted a retrospective chart review of patients seeking consultation at a cosmetic dermatology practice, recorded patients' use of psychotropic medicines, and compared this with data from a control group of medical dermatology patients.

RESULTS

Both groups reported rates of psychotropic medication use above those expected in the general population. There was no statistically significant difference in the prevalence of psychotropic drug use between cosmetic (18%) and medical (17%) dermatology patients.

LIMITATIONS

There is not a one-to-one correspondence between psychotropic medication use and the presence of psychopathology. Data are based on patient health histories and, thus, may be subject to underreporting.

CONCLUSIONS

There is a relatively high rate of psychotropic drug use among all patients seeking care from dermatologists, but this does not appear to be more common among patients interested in undergoing cosmetic procedures.

Biological nomenclatures: a source of lexical knowledge and ambiguity

There has been increased work in developing automated systems that involve natural language processing (NLP) to recognize and extract genomic information from the literature. Recognition and identification of biological entities is a critical step in this process. NLP systems generally rely on nomenclatures and ontological specifications as resources for determining the names of the entities, assigning semantic categories that are consistent with the corresponding ontology, and assignment of identifiers that map to well-defined entities within a particular nomenclature. Although nomenclatures and ontologies are valuable for text processing systems, they were developed to aid researchers and are heterogeneous in structure and semantics. A uniform resource that is automatically generated from diverse resources, and that is designed for NLP purposes would be a useful tool for the field, and would further database interoperability. This paper presents work towards this goal. We have automatically created lexical resources from four model organism nomenclature systems (mouse, fly, worm, and yeast), and have studied performance of the resources within an existing NLP system, GENIES. Using nomenclatures is not straightforward because issues concerning ambiguity, synonymy, and name variations are quite challenging. In this paper we focus mainly on ambiguity. We determined that the number of ambiguous gene names within the individual nomenclatures, across the four nomenclatures, and with general English ranged from 0%-10.18%, 1.187%-20.30%, and 0%-2.49% respectively. When actually processing text, we found the rate of ambiguous occurrences (not counting ambiguities stemming from English words) to range from 2.4%-32.9% depending on the organisms considered.

Hormonal regulation of interleukin-6 production in human adipocytes

OBJECTIVE

To elucidate the hormonal regulation of interleukin-6 (IL-6) production by human adipose tissue and its relation to leptin.

DESIGN

In vitro study. Human adipocytes were incubated with dexamethasone (with or without RU486), norepinephrine and epinephrine (with or without propranolol), or insulin.

MEASUREMENTS

IL-6 and leptin secretion by human adipocytes.

RESULTS

A gradual increase in IL-6 secretion by adipocytes during differentiation was observed. A positive correlation was found between basal IL-6 release and both glycerol 3-phosphate dehydrogenase activity--a marker of adipocyte differentiation-and leptin release. Dexamethasone decreased IL-6 secretion and increased leptin secretion in a dose-dependent manner. Both catecholamines increased IL-6 and leptin secretion. The effects of dexamethasone and catecholamines on IL-6 and leptin were abrogated by RU486 and propranolol, respectively. Incubation with insulin resulted in a dose-dependent stimulation of IL-6 and leptin secretion.

CONCLUSIONS

IL-6 is produced by human adipocytes and is a potential marker of adipocyte differentiation. Furthermore it is a hormonally regulated cytokine, suppressed by glucocorticoids, and stimulated by catecholamines and insulin in physiological concentrations.

GENIES: a natural-language processing system for the extraction of molecular pathways from journal articles

Systems that extract structured information from natural language passages have been highly successful in specialized domains. The time is opportune for developing analogous applications for molecular biology and genomics. We present a system, GENIES, that extracts and structures information about cellular pathways from the biological literature in accordance with a knowledge model that we developed earlier. We implemented GENIES by modifying an existing medical natural language processing system, MedLEE, and performed a preliminary evaluation study. Our results demonstrate the value of the underlying techniques for the purpose of acquiring valuable knowledge from biological journals.

The efficacy and safety of once-daily Kytril (granisetron hydrochloride) tablets in the prophylaxis of nausea and emesis following fractionated upper abdominal radiotherapy

This multicenter, randomized, double-blind study compared the efficacy and safety of once-daily oral granisetron 2 mg (n = 134) and placebo (n = 126) as prophylaxis for nausea and emesis in patients receiving upper abdominal fractionated radiotherapy. Patients were scheduled to receive 10-30 fractions of radiotherapy; granisetron (two 1-mg tablets) or placebo was administered 1 hr before radiotherapy on each scheduled treatment day. Treatment comparisons were made at 24 hr and at 10 and 20 fractions. Patients treated with granisetron experienced greater emetic control than those treated with placebo as evidenced by median times to first emesis (35 vs. 9 days, p < 0.001) and first nausea (11 vs. 1 day, p < 0.001). Overall endpoint analysis showed that proportionally more granisetron than placebo patients were emesis free (57.5% vs. 42.1%, p = 0.0047) and nausea free (30.6% vs. 16.7%, p = 0.0042). Furthermore, 25% more granisetron-treated than placebo-treated patients were emesis free and 20% more were nausea free on at least 80% of study treatment days. The most commonly reported adverse experiences in granisetron-treated patients were diarrhea, asthenia, and constipation. These findings demonstrate that a once-daily, 2-mg dose of oral granisetron is well tolerated and significantly more effective than placebo in preventing nausea and emesis induced by fractionated radiotherapy to the upper abdomen.

Identification of non-functional human VNO receptor genes provides evidence for vestigiality of the human VNO

In mammals, the vomeronasal organ (VNO) contains chemosensory receptor cells that bind to pheromones and induce a variety of social and reproductive behaviors. It has been traditionally assumed that the human VNO (Jacobson's organ) is a vestigial structure, although recent studies have shown minor evidence for a structurally intact and possibly functional VNO. The presence and function of the human VNO remains controversial, however, as pheromones and VNO receptors have not been well characterized. In this study we screened a human Bacterial Artificial Chromosome (BAC) library with multiple primer sets designed from human cDNA sequences homologous to mouse VNO receptor genes. Utilizing these BAC sequences in addition to mouse VNO receptor sequences, we screened the High Throughput Genome Sequence (HTGS) database to find additional human putative VNO receptor genes. We report the identification of 56 BACs carrying 34 distinct putative VNO receptor gene sequences, all of which appear to be pseudogenes. Sequence analysis indicates substantial homology to mouse V1R and V2R VNO receptor families. Furthermore, chromosomal localization via FISH analysis and RH mapping reveal that the majority of the BACs are localized to telomeric and centromeric chromosomal localizations and may have arisen through duplication events. These data yield insight into the present state of pheromonal olfaction in humans and into the evolutionary history of human VNO receptors.

Transcriptional activity of multiple copies of a subtelomerically located olfactory receptor gene that is polymorphic in number and location

We report here on the transcriptional activity of multiple copies of a subtelomerically located olfactory receptor (OR) gene, OR-A. Due to recent duplication events, both the copy number and chromosomal location of OR-A vary among humans. Sequence analyses of 180 copies of this gene, derived from 12 chromosome ends in 22 individuals, show that the main coding exon of all but one copy is an intact open reading frame with 0-5 predicted amino acid differences. We detected transcription of OR-A in both olfactory epithelium and testis tissue using RT-PCR amplification with primers designed on the basis of a computationally predicted gene structure. Two alternatively spliced forms of transcripts, one encoding an isoform with an extended N-terminus, were found in both tissues. A third transcript, derived from a second promoter, was also observed in testes. The start methionine is predicted in all transcripts to lie in an upstream exon rather than the main coding exon, as is typical for most other OR genes. By examining sequence variants among transcripts, we show that transcription of this gene occurs at multiple chromosomal locations. Our results lend credence to the idea that OR diversity could be generated in rearrangement-prone subtelomeric regions and show that polymorphism in subtelomeric regions could lead to individual-to-individual variation in the expressed repertoire of OR genes.

Electronic chart review as an aid to postdischarge surgical site surveillance: increased case finding

BACKGROUND

At the University of Michigan Hospitals and Health Centers, there is increasing use of an electronic medical record. Because orthopedic surgeons dictate all outpatient visits to the patient's electronic record, total knee arthroplasties were chosen to determine whether the use of electronic medical records increased case finding.

METHODS

All patients who underwent a total knee arthroplasty during the study period (1996-1999) were followed prospectively with the use of the National Nosocomial Infection Surveillance System definitions. Traditional surveillance methods were used to ascertain infections. In addition, each patient's postdischarge outpatient clinic chart was reviewed electronically for 1 year after operation.

RESULTS

From 1996 to 1999, 555 procedures were performed. Overall, 25 infections were identified after operation. Seven infections were identified through traditional surveillance methods, which resulted in an average surgical site infection rate of 1.3%. The use of electronic chart review surveillance after discharge revealed a rate of 4.5%, which was significantly higher than traditional surveillance (P <.01). Eighteen of 25 infections (72%) would not have been identified with the use of traditional surveillance methods.

CONCLUSION

Postdischarge electronic chart review enhanced case finding significantly, which resulted in a more accurate infection rate. Awareness should be given to the institutions' surveillance methods and intensity when comparing to published rates.

Disambiguating ambiguous biomedical terms in biomedical narrative text: an unsupervised method

With the growing use of Natural Language Processing (NLP) techniques for information extraction and concept indexing in the biomedical domain, a method that quickly and efficiently assigns the correct sense of an ambiguous biomedical term in a given context is needed concurrently. The current status of word sense disambiguation (WSD) in the biomedical domain is that handcrafted rules are used based on contextual material. The disadvantages of this approach are (i) generating WSD rules manually is a time-consuming and tedious task, (ii) maintenance of rule sets becomes increasingly difficult over time, and (iii) handcrafted rules are often incomplete and perform poorly in new domains comprised of specialized vocabularies and different genres of text. This paper presents a two-phase unsupervised method to build a WSD classifier for an ambiguous biomedical term W. The first phase automatically creates a sense-tagged corpus for W, and the second phase derives a classifier for W using the derived sense-tagged corpus as a training set. A formative experiment was performed, which demonstrated that classifiers trained on the derived sense-tagged corpora achieved an overall accuracy of about 97%, with greater than 90% accuracy for each individual ambiguous term.

Genomic analysis of orthologous mouse and human olfactory receptor loci

Olfactory receptor (OR) genes represent approximately 1% of genomic coding sequence in mammals, and these genes are clustered on multiple chromosomes in both the mouse and human genomes. We have taken a comparative genomics approach to identify features that may be involved in the dynamic evolution of this gene family and in the transcriptional control that results in a single OR gene expressed per olfactory neuron. We sequenced approximately 350 kb of the murine P2 OR cluster and used synteny, gene linkage, and phylogenetic analysis to identify and sequence approximately 111 kb of an orthologous cluster in the human genome. In total, 18 mouse and 8 human OR genes were identified, including 7 orthologs that appear to be functional in both species. Noncoding homology is evident between orthologs and generally is confined within the transcriptional unit. We find no evidence for common regulatory features shared among paralogs, and promoter regions generally do not contain strong promoter motifs. We discuss these observations, as well as OR clustering, in the context of evolutionary expansion and transcriptional regulation of OR repertoires.

A homogeneous fluorometric assay for measuring cell adhesion to immobilized ligand using V-well microtiter plates

We have developed a homogeneous high-capacity assay format for measuring integrin- and selectin-dependent cell binding to immobilized ligand using V-well microtiter plates. 2',7'-Bis(2-carboxyethyl)-5-(and-6)-carboxylfluorescence, acetoxymethylester-labeled cells are added to ligand-coated V-shaped microtiter wells. Bound cells are separated from free cells using centrifugal force to produce shear stress. Nonadherent cells accumulate in the nadir of the well and are measured using a fluorescence plate reader. Antibody or low-molecular-weight inhibitors of either the ligand or the cell surface receptor result in less cell binding, more cells in the pellet, and increased signal. The optimization and validation of the very late antigen-4/vascular cell adhesion molecule-1 assay is described in detail. We demonstrate that this assay can be rapidly adapted to measure other integrin- and selectin-mediated interactions. This assay format has several advantages over conventional assays. The centrifugal process is biologically relevant and eliminates the washing steps to remove nonadherent cells that can cause well-to-well and plate-to-plate variation. Because the assay is robust with a high signal-to-noise ratio and low variability, it is ideally suited for studying multiple parameters of cell adhesion and for high capacity screening.

Efficacy of intravenous granisetron to control nausea and vomiting during multiple cycles of cisplatin-based chemotherapy

The safety and efficacy of granisetron (10 micrograms/kg and 40 micrograms/kg) were evaluated during a second (n = 393) and third (n = 200) cycle of chemotherapy in this multicenter, double-blind, randomized, parallel-group study. Granisetron was administered as a single intravenous dose before the start of cisplatin chemotherapy (> or = 60 mg/m2). Total control (no vomiting, no retching, no nausea, and no use of antiemetic rescue medication) after the first 24 hr following chemotherapy was achieved in 40% and 49% of patients in Cycles 2 and 3, respectively, for the 10 micrograms/kg group, and in 42% and 38% of patients in Cycles 2 and 3, respectively, for the 40 micrograms/kg group. Both dose levels of granisetron were well tolerated. The results demonstrate comparable efficacy between the 10 micrograms/kg and 40 micrograms/kg doses of granisetron in preventing nausea and vomiting during repeat cycles of high-dose cisplatin-based chemotherapy. The results of this study show that granisetron 10 micrograms/kg is safe and well tolerated, and remains effective with repeat cycle use.

Randomized trial of supplemental beta-carotene to prevent second head and neck cancer

Beta-carotene has established efficacy in animal models of oral carcinogenesis and has been shown to regress oral precancerous lesions in humans. The purpose of this study was to see whether these effects extended to the prevention of oral/pharyngeal/laryngeal (head and neck) cancer in humans. The subject population for this randomized, placebo-controlled, double-blinded clinical trial included 264 patients who had been curatively treated for a recent early-stage squamous cell carcinoma of the oral cavity, pharynx, or larynx. Patients were assigned randomly to receive 50 mg of beta-carotene per day or placebo and were followed for up to 90 months for the development of second primary tumors and local recurrences. After a median follow-up of 51 months, there was no difference between the two groups in the time to failure [second primary tumors plus local recurrences: relative risk (RR), 0.90; 95% confidence interval (CI), 0.56-1.45]. In site-specific analyses, supplemental beta-carotene had no significant effect on second head and neck cancer (RR, 0.69; 95% CI, 0.39-1.25) or lung cancer (RR, 1.44; 95% CI, 0.62-3.39). Total mortality was not significantly affected by this intervention (RR, 0.86; 95% CI, 0.52-1.42). Whereas none of the effects were statistically significant, the point estimates suggested a possible decrease in second head and neck cancer risk but a possible increase in lung cancer risk. These effects are consistent with the effects observed in trials using intermediate end point biological markers in humans, in which beta-carotene has established efficacy in oral precancerous lesions but has no effect or slightly worsens sputum cytology, and in animal carcinogenicity studies, in which beta-carotene has established efficacy in buccal pouch carcinogenesis in hamsters but not in animal models of respiratory tract/lung carcinogenesis, with some suggestions of tumor-promoting effects in respiratory tract/lung. If our results are replicated by other ongoing/completed trials, this suggests a critical need for mechanistic studies addressing differential responses in one epithelial site (head and neck) versus another (lung).