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David T Wong

Publications and source records attributed to David T Wong.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of salivary RNA by cDNA library analysis.

Oral fluid (saliva) meets the demands for a noninvasive and accessible diagnostic medium. Recent reports by our group and others described the presence and use of human RNA in saliva as a diagnostic or forensic tool, including the use for oral cancer detection. To gain insights into the integrity of salivary RNA, we examined in detail the integrity of salivary RNA by generating a cDNA library from pooled supernatant saliva of 10 healthy donors. From a library with a primary library titer of 1.3 x 10(6) cfu/mL of which 95% of the clones had inserts, we successfully sequenced 117 random colonies containing recombinant clones. BLAST search results indicated that all of these clones contained sequences of human origin. Most of the salivary RNAs appeared to be endonucleolytically cleaved at random positions as indicated by comparisons to respective full length parental RNAs from the Genbank. Twelve of the insert sequences matched to the normal salivary core transcriptome sequences, which are highly abundant mRNAs present in healthy individuals. This study provides an in-depth molecular analysis of the saliva transcriptome and should be a useful resource for future basic and translational studies of RNA in human saliva. In addition, this paper presents unequivocal evidence for the presence of RNA in saliva as determined by the use of diverse techniques such as reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), in vitro translation, and the construction of a salivary cDNA library.

Adult↗
PubMed2006

Characterization of RNA in saliva.

BACKGROUND: We have previously shown that human mRNAs are present in saliva and can be used as biomarkers of oral cancer. In this study, we analyzed the integrity, sources, and stability of salivary RNA. METHODS: We measured the integrity of salivary RNA with reverse transcription followed by PCR (RT-PCR) or RT-quantitative PCR (RT-qPCR). To study RNA entry sites into the oral cavity, we used RT-PCR analysis of salivary RNA from the 3 major salivary glands, gingival crevice fluid, and desquamated oral epithelial cells. We measured stability of the salivary beta-actin mRNA by RT-qPCR of salivary RNA incubated at room temperature for different periods of time. We measured RNA association with other macromolecules by filtering saliva through pores of different sizes before performing RT-qPCR. To assess RNA-macromolecule interaction, we incubated saliva with Triton X-100 for different periods of time before performing RT-qPCR. RESULTS: In most cases, we detected partial- to full-length salivary mRNAs and smaller amounts of middle and 3' gene amplicons compared with the 5'. RNA was present in all oral fluids examined. Endogenous salivary beta-actin mRNA degraded more slowly than exogenous beta-actin mRNA, with half-lives of 12.2 and 0.4 min, respectively (P <0.001). Salivary RNA could not pass through 0.22 or 0.45 mum pores. Incubation of saliva with Triton X-100 accelerated degradation of salivary RNA. CONCLUSIONS: Saliva harbors both full-length and partially degraded forms of mRNA. RNA enters the oral cavity from different sources, and association with macromolecules may protect salivary RNA from degradation.

Adult↗
PubMed2006

Serum circulating human mRNA profiling and its utility for oral cancer detection.

PURPOSE: The purpose of this study is to explore the presence of informative RNA biomarkers from human serum transcriptome, and evaluate the serum transcriptome diagnostics for disease detection. Oral squamous cell carcinoma (OSCC) was selected as the proof-of-concept disease. PATIENTS AND METHODS: Blood samples were collected from patients (n = 32) with primary T1/T2 OSCC and matched healthy patients (n = 35). Circulating RNA was isolated from serum and linearly amplified using T7 polymerase. Microarrays were applied for profiling transcriptome in serum from 10 cancer patients and controls. The differential gene expression was analyzed by combining the present calls, t tests, and fold-change statistics. Quantitative polymerase chain reaction (PCR) was used to validate the selected candidate RNA markers identified by microarray. Receiver operating characteristic curve and classification models were exploited to evaluate the diagnostic power of these markers for OSCC. RESULTS: Human serum circulating mRNAs were presented by reverse transcriptase PCR. Microarray identified 2,623 +/- 868 probes assigned present calls in OSCC (n = 10) versus 1,792 +/- 165 in healthy patients (n = 10), indicating a higher complexity of serum transciptome in OSCC patients (P = .002, Wilcoxon test). Three hundred thirty-five serum RNAs exhibited significantly differential expression level between the two groups (P < .05, t test; fold > or = 2). Five cancer-related gene transcripts were consistently validated by quantitative PCR on serum from OSCC patients (n = 32) and controls (n = 35). The best combination of biomarkers yielded a receiver operating characteristic curve value of 88%, sensitivity (91%), and specificity (71%) in distinguishing OSCC. CONCLUSION: The utility of serum transcriptome diagnostics is successfully demonstrated for OSCC detection. This novel concept could be developed as an adjunctive tool for disease diagnosis.

Biomarkers↗
PubMed2006

Human body fluid proteome analysis.

The focus of this article is to review the recent advances in proteome analysis of human body fluids, including plasma/serum, urine, cerebrospinal fluid, saliva, bronchoalveolar lavage fluid, synovial fluid, nipple aspirate fluid, tear fluid, and amniotic fluid, as well as its applications to human disease biomarker discovery. We aim to summarize the proteomics technologies currently used for global identification and quantification of body fluid proteins, and elaborate the putative biomarkers discovered for a variety of human diseases through human body fluid proteome (HBFP) analysis. Some critical concerns and perspectives in this emerging field are also discussed. With the advances made in proteomics technologies, the impact of HBFP analysis in the search for clinically relevant disease biomarkers would be realized in the future.

Acute-Phase Proteins↗
PubMed2006

Case report: Endotracheal tube malposition in a patient with a tracheal bronchus.

PURPOSE: A tracheal bronchus is a congenital abnormality of the tracheobronchial tree, in which a displaced or accessory bronchus arises from the trachea superior to its bifurcation. We report a patient with a tracheal bronchus that was found incidentally during surgery in the prone position, and the potential airway management problems which may have ensued. CLINICAL FEATURES: A 70-yr-old female underwent posterior spinal decompression and fusion in the prone position. Intraoperatively, end-tidal CO2 and airway pressure increased. Fibreoptic bronchoscopy revealed that the endotracheal tube (ETT) was kinked at the 16 cm mark, which was corrected by rotating the patient's head and ETT. When the bronchoscope was advanced beyond the tip of the ETT, a tracheal-bronchial tree trifurcation was identified. Endobronchial intubation was suspected. As the ETT was withdrawn, the endoluminal view remained unchanged. During bronchoscopy, the patient's trachea was nearly extubated in the prone position. Subsequent bronchoscopy of the major bronchial divisions showed that the trifurcation represented left main stem bronchus, bronchus intermedius and right upper lobe bronchus. Once the tracheal bronchus was recognized, the tip of the ETT was repositioned 3 cm above the tracheal trifurcation, and the rest of the case was uneventful. CONCLUSION: This case highlights the diagnostic challenge and airway management implications of one variant of a tracheal bronchus when airway problems are encountered intraoperatively. This knowledge should be applied in the differential diagnosis and management of intraoperative hypoxemia; and in the proper positioning of the ETT.

Aged↗
PubMed2006

Anterior uveitis investigation by Canadian ophthalmologists: insights from the Canadian National Uveitis Survey.

BACKGROUND: Anterior uveitis can be the result of a number of underlying etiologies and is commonly seen in ophthalmology practice. The clinician must choose from a battery of potential investigations. A nonselective approach to testing is costly and inefficient and can lead to misinterpretation of false positive results. The purpose of this study was to identify investigation patterns of ophthalmologists in Canada for anterior uveitis and to make evidence-based recommendations for appropriate tests that could lead to improved patient care and more cost-effective use of health care resources. METHODS: A cross-sectional survey of practicing ophthalmologists, fellows, and residents in Canada was conducted in September 2004. The survey instrument was an 11-item questionnaire mailed to 1196 physicians in Canada. RESULTS: A total of 498 (42%) physicians responded to the survey. A wide range of tests were chosen when respondents were presented with 5 scenarios for anterior uveitis and asked what investigations they would order. Many of these tests have low diagnostic yields because they lack the sensitivity and specificity to be used as routine investigations in the setting of anterior uveitis. INTERPRETATION: Increased education and awareness could lead to more cost-effective and efficient investigations in the setting of anterior uveitis. On the basis of evidence from a review of the literature, we make recommendations for investigations that should be considered in patients with anterior uveitis.

Canada↗
PubMed2006

Identification of N-linked glycoproteins in human saliva by glycoprotein capture and mass spectrometry.

Glycoproteins make up a major and important part of the salivary proteome and play a vital role in maintaining the health of the oral cavity. Because changes in the physiological state of a person are reflected as changes in the glycoproteome composition, mapping the salivary glycoproteome will provide insights into various processes in the body. Salivary glycoproteins were identified by the hydrazide coupling and release method. In this approach, glycoproteins were coupled onto a hydrazide resin, the proteins were then digested and formerly N-glycosylated peptides were selectively released with the enzyme PNGase F and analyzed by LC-MS/MS. Employing this method, coupled with in-solution isoelectric focusing separation as an additional means for pre-fractionation, we identified 84 formerly N-glycosylated peptides from 45 unique N-glycoproteins. Of these, 16 glycoproteins have not been reported previously in saliva. In addition, we identified 44 new sites of N-linked glycosylation on the proteins.

Amino Acid Sequence↗
PubMed2006

Use of telemedicine in chronic pain consultation: a pilot study.

OBJECTIVES: Telemedicine has been used extensively in various settings, including monitoring patient treatment response and counseling. However, there are few data on the application of telemedicine to chronic pain patients. The present study was the first pilot project to determine whether telemedicine technology for chronic pain consultation was feasible, cost-saving, and satisfactory to patients and pain physicians. METHODS: A prospective pilot study was conducted on chronic pain patients requiring follow-up consultations using telemedicine technology. Patients were interviewed by phone following the consultation. RESULTS: Eleven telemedicine anesthesia consultations involving eight patients (age 42+/-9 years; six men, two women) were performed. All were follow-up consultations. The average distance from patients' home to the clinic was 314+/-170 km. The reasons for consultation were for update of patient progress (10/11), medication change (6/11), and counseling (3/11). The time to complete the consultation was 24.5+/-9.5 minutes. The data for the time and the cost that the patient spent on the consultation are presented as median and 25% to 75% interquartile range. Patients having telemedicine consultations spent 0.9 hours (0.83-1) and Canadian dollar 3 (dollar 2-4) versus an estimate of 8 hours (6-8) and Canadian dollar 80 (dollar 46-260) for a conventional consultation (both P<0.005). Telemedicine consultation was found to be highly satisfactory to the patient and the consulting and attending anesthesiologists. CONCLUSIONS: This pilot study indicates that telemedicine follow-up consultations for chronic pain patients are feasible and cost-saving. Patients and anesthesiologists were highly satisfied with telemedicine consultation. Patients reported a significant saving in time and cost compared with a conventional consultation.

Adult↗
PubMed2006

Salivary diagnostics powered by nanotechnologies, proteomics and genomics.

BACKGROUND: The ability to monitor health status, disease onset and progression, and treatment outcome through noninvasive means is a highly desirable goal in health care promotion and delivery. Oral fluid is a perfect medium to be explored for health and disease surveillance. METHODS: Two prerequisites exist before the goal of salivary diagnostics can be achieved: identification of specific biomarkers associated with a health or disease state and the development of technologies that can discriminate between the biomarkers. A recent initiative of the National Institute of Dental and Craniofacial Research has created a roadmap to achieve these goals through the use of oral fluids as the diagnostic medium to scrutinize the health and/or disease status of patients. This is an ideal opportunity to optimize state-of-the-art saliva-based biosensors for salivary biomarkers that discriminate between diseases. RESULTS: Seven technology groups are developing point-of-care salivary diagnostic technologies. Three groups are working together toward deciphering the salivary proteome. CONCLUSION: These collective efforts and the convergence of salivary diagnostic technologies and the salivary proteome will present unparalleled opportunities to explore the diagnostic potential of saliva for oral and systemic diseases.

Biomarkers↗
PubMed2006

Global expression-based classification of lymph node metastasis and extracapsular spread of oral tongue squamous cell carcinoma.

Regional lymph node metastasis is a critical event in oral tongue squamous cell carcinoma (OTSCC) progression. The identification of biomarkers associated with the metastatic process would provide critical prognostic information to facilitate clinical decision making for improved management of OTSCC patients. Global expressional profiles were obtained for 25 primary OTSCCs, where 11 cases showed lymph node metastasis (pN+) histologically and 14 cases were nonmetastatic (pN-). Seven of pN+ cases also exhibited extracapsular spread (ECS) of metastatic nodes. Multiple expression indices were used to generate signature gene sets for pN+/- and ECS+/- cases. Selected genes from signature gene sets were validated using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The classification powers of these genes were then evaluated using a logistic model, receiver operating characteristic curve analysis, and leave-one-out cross-validation. qRT-PCR validation data showed that differences at RNA levels are either statistically significant (P < .05) or suggestive (P < .1) for six of eight genes tested (BMP2, CTTN, EEF1A1, GTSE1, MMP9, and EGFR) for pN+/- cases, and for five of eight genes tested (BMP2, CTTN, EEF1A1, MMP9, and EGFR) for ECS+/- cases. Logistic models with specific combinations of genes (CTTN+MMP9+EGFR for pN and CTTN+EEF1A1+MMP9 for ECS) achieved perfect specificity and sensitivity. Leave-one-out cross-validation showed overall accuracy rates of 85% for both pN and ECS prediction models. Our results demonstrated that the pN and the ECS of OTSCCs can be predicted by gene expression analyses of primary tumors.

Adult↗
PubMed2006

Loss of p12CDK2-AP1 expression in human oral squamous cell carcinoma with disrupted transforming growth factor-beta-Smad signaling pathway.

We examined correlations between TGF-beta1, TbetaR-I and TbetaR-II, p12(CDK2-AP1), p21(WAF1), p27(KIP1), Smad2, and p-Smad2 in 125 cases of human oral squamous cell carcinoma (OSCC) to test the hypothesis that resistance to TGF-beta1-induced growth suppression is due to the disruption of its signaling pathway as a consequence of reduced or lost p12(CDK2-AP1). Immunoreactivity for TbetaR-II decreased in OSCC with increasing disease aggressiveness; however, no differences were observed for TbetaR-I and TGF-beta1. The expression of TbetaR-II significantly correlated with p12(CDK2-AP1) and p27(KIP1) (P < .001 and P < .01, respectively). Furthermore, there was a significant relationship between TbetaR-II expression and p-Smad2 (P < .001). The in vivo correlation of the levels of TbetaR-II, p12(CDK2-AP1), and p27(KIP1) was confirmed in normal and OSCC cell lines. Additionally, in vitro analysis of TGF-beta1-treated cells showed that TGF-beta1 treatment of normal keratinocytes suppressed cell growth with upregulation of p-Smad2, p12(CDK2-AP1), and p21(WAF1) expression, whereas there was no effect on OSCC cell lines. These results provide evidence of a link between a disrupted TGF-beta-Smad signaling pathway and loss of induction of cell cycle-inhibitory proteins, especially p12(CDK2-AP1) in OSCC, which may lead to the resistance of TGF-beta1 growth-inhibitory effect on OSCC.

Aged↗
PubMed2006

Salivary diagnostics.

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Diagnostic Techniques and Procedures↗
PubMed2006

Salivary diagnostics for oral cancer.

Oral cancers annually strike 38,000 individuals in the United States and hundreds of thousands of others around the globe. Despite treatment advances, the disease's overall five-year survival rate has not improved in the past three decades and remains among the worst of all cancers. One factor behind oral cancer's high mortality is the challenge detecting it at its early stages. The use of saliva for the detection of oral cancer has been a historical goal that has yet to come to fruition. This review highlights translational research efforts in alignment with initiatives sparked by the National Institute of Dental and Craniofacial Research toward bringing saliva diagnostics to fruition and, in particular, for saliva-based oral cancer detection.

Biopsy↗
PubMed2006

Cultural, behavioral, social, and psychological perceptions of saliva: relevance to clinical diagnostics.

The search for a resource that can be used to detect a broad range of diseases easily and reliably is akin to a search for the diagnostic Holy Grail. Yet, each of us may have inside our mouths, a key to the pathological and disease biomarker library hidden inside our bodies. Saliva--the source of all this information--is the secretory product of glands located in or around the oral cavity. If one could read the stories of diagnostic information present within saliva, then the abundance of information waiting to be found could be comparable to a vast vault of information, such as the Internet. Upon dissection of this data, it would be seen that the source of this information is from saliva's origin as a filtrate of blood, and that the validity of both mediums should be equal. Although one day this may be the view, most people's hold of saliva, current and past cultures, have fared much more diverse meanings to the secretion. Ivan Pavlov's experiments has shown how closely tied salivation is with the thought of food, one of life's primary indulgences. The relationship between salivation and behaviors within our daily lives is undeniable. Yet most people never appreciate the uniqueness of saliva. Throughout the world, saliva carries definite positive and negative connotations, based upon its social, psychological, behavioral, and cultural settings. The thought of saliva may be viewed as grotesque in one population, yet may be the vehicle of blessing in other cultures. Saliva's double nature brings up some interesting cultural, social, behavioral, and psychological points about how saliva is perceived in the world, some of which are subsequently stated in order to present saliva as the spirited fluid it is.

Ceremonial Behavior↗
PubMed2006

Evaluation of bronchoscopic-assisted percutaneous tracheostomy.

The convenience of bedside percutaneous tracheostomy (PT) is growing in popularity. Some centers are placing PTs without the assistance of bronchoscopy. The study objective was to identify operative and perioperative problems with PT placement and to identify potential problems with bronchoscopy-free placement. All operative and perioperative events were prospectively recorded as a performance improvement project at our institution while performing bronchoscopic-assisted bedside PTs. One hundred eighty-three patients underwent PT placement, all with the assistance of a bronchoscope. Although most PT was performed without incident, some of the complications can be severe. The majority of difficulties can be prevented with bronchoscopic assistance. An unexpected procedural difficulty that has not been previously reported is the dilatational difficulty in the younger patient population. Some of these patients required an additional tracheal incision with a scalpel. This may be from a healthy pretracheal fascia and/or musculature.

Adolescent↗