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Biomedical subjects

K M Wilson

Publications and source records attributed to K M Wilson.

At least 19 recordsLinked to original sources
PubMed1998

Detection of dimers of dimers of human leukocyte antigen (HLA)-DR on the surface of living cells by single-particle fluorescence imaging.

The technique of single-particle fluorescence imaging was used to investigate the oligomeric state of MHC class II molecules on the surface of living cells. Cells transfected with human leukocyte antigen (HLA)-DR A and B genes were labeled at saturation with a univalent probe consisting of Fab coupled to R-phycoerythrin. Analysis of the intensities of fluorescent spots on the cell surface revealed the presence of single and double particles consistent with the simultaneous presence of HLA-DR heterodimers and dimers of dimers. The proportion of double particles was lower at 37 degrees C than at 22 degrees C, suggesting that the heterodimers and dimers of dimers exist in a temperature-dependent equilibrium. These results are discussed in the context of a possible role for HLA-DR dimers of dimers in T cell receptor-MHC interactions. The technique is validated by demonstrating that fluorescence imaging can distinguish between dimers and tetramers of human erythrocyte spectrin deposited from solution onto a solid substrate. The methodology will have broad applicability to investigation of the oligomeric state of immunological and other membrane-bound receptors in living cells.

Cell Line↗
PubMed1998

Alloantigen gene therapy for squamous cell carcinoma of the head and neck: results of a phase-1 trial.

OBJECTIVE: To determine the safety and efficacy of an immunogenic gene therapy using a drug designed to produce expression of a foreign class I major histocompatibility complex protein in patients with head and neck cancer. DESIGN: Phase 1 prospective clinical trial. SETTING: Academic medical setting. PATIENTS: Nine patients with advanced head and neck squamous cell carcinoma who had failed conventional therapy and did not express HLA-B7, a class I major histocompatibility complex protein. INTERVENTION: Patients were treated with Allovectin-7 (Vical Inc, San Diego, Calif) by direct intratumoral injection. Allovectin-7 contains a plasmid complementary DNA complexed with a cationic lipid, which results in expression of HLA-B7. MAIN OUTCOME MEASURES: Patients were assessed for any toxic effects and for any change in tumor volume. Biopsy specimens obtained before and after therapy were evaluated by immunohistochemistry to detect HLA-B7 expression and with the terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay to detect any induction of apoptosis. RESULTS: There were no toxic effects of the gene therapy. In 4 of these 9 patients there was a partial response to treatment, evidenced by a gradual reduction in tumor size. One patient has remained alive for more than 17 months since commencing treatment, with no clinical evidence of disease but with persistent histological evidence of cancer. Analysis of the biopsy specimens from 2 of the patients who responded to therapy demonstrated HLA-B7 expression. The TUNEL assay demonstrated extensive apoptosis in both of these patients, suggesting that this may be the mechanism of tumor reduction. CONCLUSIONS: These data demonstrate the potential efficacy and lack of toxicity of this form of alloantigen gene therapy. A multi-institutional study has been initiated to expand on these findings.

Adult↗
PubMed1998

Stability of midazolam and fentanyl in infusion solutions.

The administration of drugs by subcutaneous infusion is routinely practiced in palliative medicine for the management of patients who are no longer able to take oral medication. It is not uncommon for two or more drugs to be combined in subcutaneous infusion solutions. The combination of an opioid and a short-acting benzodiazepine is frequently required. Unfortunately, the stability of benzodiazepines and newer opioids, such as fentanyl, has not been determined. This study examined the stability of solutions containing either fentanyl alone or fentanyl and midazolam in combination. Eight different solutions were assessed for up to 7 days following preparation. The solutions were prepared in polypropylene syringes using 0.9% saline as a diluent. Duplicate syringes were stored at approximately 5 degrees C, 22 degrees C, and 38 degrees C. High performance liquid chromatography was the analytical technique used to measure fentanyl and midazolam. Initial concentrations ranges were 13.2-38.9 micrograms/mL for fentanyl and 282-959 micrograms/mL for midazolam. It was found that fentanyl (+/- midazolam) was very stable (> 95%) when stored at temperatures ranging from 5 degrees C to 38 degrees C for at least 1 week. Midazolam (+ fentanyl) was not as stable as fentanyl under the same storage conditions and underwent time-dependent decomposition of up to 12.1% (observed at 7 days when stored at 38 degrees C). When stored at 22 degrees C and 38 degrees C, more than 90% of initial midazolam concentrations were retained for 4 days following preparation and for 7 days when stored at 5 degrees C. The clinical implications of these results are that, on the basis of physicochemical stability, subcutaneous infusion solutions containing fentanyl and midazolam may be prepared at intervals of 4 days (or 7 days if stored under refrigerated conditions).

Analgesics, Opioid↗
PubMed1998

Effects of hemimandibulectomy on quality of life.

OBJECTIVE: To assess the quality of life and functional status of patients who have undergone hemimandibulectomy based on the type of reconstructive procedure performed. STUDY DESIGN: Survey, retrospective. METHODS: Twenty-one patients who had undergone hemimandibulectomy and had similar defects were divided into two groups based on the reconstructive technique utilized. Eleven patients were placed in the soft tissue reconstruction group. Ten patients were placed in the mandible reconstruction group. All patients were assessed for: function, utilizing the Performance Status Scale, and quality of life, using a general cancer questionnaire (FACT-G) and a series of questions specific for head and neck cancer patients. RESULTS: Mandible reconstruction produced a perceived better physical appearance (P = .02), better eating ability (P = .04), and a better overall quality of life (P = .002). The mandible reconstruction cohort consistently outscored the soft tissue cohort on all questionnaires. CONCLUSION: Restoration of mandibular continuity after hemimandibulectomy leads to improved function and a superior quality of life in appropriately selected patients.

Adult↗
PubMed1998

Improved solid-phase extraction technique for plasma flecainide analysis by high-performance liquid chromatography.

A method for analyzing flecainide in plasma was developed and assessed. Based on the use of C18 extraction columns eight or fewer times, the rapid and simple extraction procedure provided consistent, high-efficiency flecainide extraction (>85%). Using reverse-phase, high-performance liquid chromatography with fluorometric detection, flecainide acetate was detectable to approximately 15 ng/ml. Retention times of the internal standard and flecainide were 8.9 to 9.2 and 9.8 to 10.4 minutes, respectively, and short sample preparation and run times enabled results to be delivered within 2 to 3 hours of receiving samples. The assay was linear for the standard range 20 ng/ml to 2 microg/ml (r2 with three standards, >0.999) and delivered a high level of accuracy. Quality control concentrations obtained from eight assays consistently fell within 5% of nominal values (100 ng/ml and 1 microg/ml). Based on four assays, the assay was also reproducible with calculated-between and within-assay coefficients of variation of less than 1% and 3%, respectively. The authors found that the performance of this assay was excellent and that the solid-phase extraction technique was simple, rapid, and cost effective.

Anti-Arrhythmia Agents↗
PubMed1997

Central auditory evaluation of patients with spasmodic dysphonia.

Spasmodic dysphonia is a focal laryngeal dystonia characterized by inappropriate contractions of the intrinsic laryngeal musculature. The prevalence of associated neurological findings has led to detailed investigation of the central nervous system. Previous research revealed latency abnormalities in patients' auditory brainstem responses. The present study further investigated central auditory findings in patients with spasmodic dysphonia, including brainstem and cortical function. Fourteen normal-hearing patients with spasmodic dysphonia were tested using the auditory brainstem response (ABR) and SCAN-A test of central auditory processing. The ABR estimated brainstem transmission time and evaluated auditory pathway integrity at a high stimulus rate. SCAN-A assessed the auditory cerebral cortex. Implications of these findings are discussed. We found no ABR abnormalities in subjects with spasmodic dysphonia. Positive SCAN-A findings were negligible. The ABR findings contradict previous reports.

Adult↗
PubMed1996

The role of toluidine blue in assessing margin status after resection of squamous cell carcinomas of the upper aerodigestive tract.

OBJECTIVE: To determine the efficacy of toluidine blue in assessing margin status after removal of squamous cell carcinomas of the upper aerodigestive tract. DESIGN: A prospective study of 50 consecutive patients undergoing surgical resection of squamous cell carcinomas of the upper aerodigestive tract was performed during February 1 to December 1, 1993. After tumor resection, toluidine blue was applied directly to the remaining unresected mucosa. The staining characteristics of the mucosa were then compared with those of frozen-section biopsy specimens of the margins and with the permanent histologic findings of the resected tumor specimen. RESULTS: In three cases, toluidine blue identified a positive margin, which was confirmed on frozen and permanent section. In six cases, false-positive staining was noted, which was most frequently related to traumatic handling of the mucosa during the resection. In no case was a positive margin found on histologic staining that failed to stain with toluidine blue. During routine staining of surrounding unresected mucosa, three cases of a second primary tumor that was not seen on routine evaluation before tumor removal were identified with toluidine blue. In one case, a second T1 oral cavity lesion was found, while in the other cases, separate pharyngeal lesions were identified. CONCLUSION: Based on these findings, it appears that toluidine blue improved the ability to assess margin status at the time of resection, and we advocate its use after resection of tumors to the upper aerodigestive tract.

Carcinoma, Squamous Cell↗
PubMed1996

Evaluation of prevertebral muscle invasion by squamous cell carcinoma. Can computed tomography replace open neck exploration?

OBJECTIVE: To compare computed tomography (CT) with open neck exploration in determining prevertebral invasion by squamous cell carcinoma of the oropharynx or hypopharynx. DESIGN: Retrospective analysis using the findings at open neck exploration and results of histopathologic studies as the criterion standards. SETTING: Tertiary care referral center. PATIENTS: Twenty-nine of 40 patients with advanced squamous cell carcinoma of the oropharynx or hypopharynx treated between January 1, 1986, and December 31, 1994, were selected for analysis based on CT findings of posterolateral extension of the primary tumor placing the prevertebral muscle (PVM) at risk. All study patients had no previous therapy and underwent neck exploration to determine resectability. RESULTS: Overall accuracy of CT in predicting PVM status was 55.2%. The sensitivity of preoperative CT for PVM invasion was 50%; the specificity was 61%. Using an estimate of 21% for the prevalence of PVM invasion, the predictive value of a positive CT scan was 0.254 and the predictive value of a negative CT scan was 0.821. Open neck exploration correctly predicted PVM status in all cases. CONCLUSIONS: Open neck exploration is superior to CT to evaluate possible PVM invasion by squamous cell carcinoma of the oropharynx or hypopharynx. The predictive value of a negative CT scan for PVM invasion is high, so it may be useful in treatment planning. Patients with advanced squamous cell carcinoma of the oropharynx or hypopharynx at risk for PVM invasion who are otherwise surgical candidates should be considered for open neck exploration to determine resectability most accurately.

Adult↗
PubMed1996

HSV-tk gene therapy in head and neck squamous cell carcinoma. Enhancement by the local and distant bystander effect.

OBJECTIVES: To determine whether the bystander effect demonstrated in vitro for ganciclovir-mediated killing of a herpes simplex virus thymidine kinase (HSV-tk) gene-infected human squamous cell carcinoma is operative in vivo in a nude mouse model. DESIGN: Prospective study in a murine model. INTERVENTION: Human head and neck squamous cell carcinoma tumors were grown as xenografts on the flanks of 20 nude mice. The tumors in the left flank were then infected with the HSV-tk gene. Then, after 48 hours, the animals were treated with intraperitoneal ganciclovir twice daily. Assessment of the tumors on both flanks was performed over a 31-day period. MAIN OUTCOME MEASURES: Resolution of tumors infected with HSV-tk gene in animals treated with ganciclovir; resolution of tumors uninfected with HSV-tk gene on the contralateral flank in animals treated with ganciclovir. RESULTS: Following HSV-tk gene therapy in nude mice, complete resolution of HSV-tk-gene-infected human head and neck squamous cell carcinoma tumors was observed following ganciclovir treatment. Uninfected tumors were also noted to regress, but not completely resolve, in response to intraperitoneal ganciclovir (distant bystander effect). CONCLUSIONS: This study confirms that the local and distant bystander effects exist in this murine model, enhancing the possibility of its role for treatment of human squamous cell carcinoma of the head and neck.

3T3 Cells↗
PubMed1996

Stage of disease confounds apparent relationship between levels of N-ras and duration of survival in head and neck tumours.

The objective of this study was to determine whether elevated levels of N-ras correlated with clinicopathological data. Complete clinical data were available on 133 of 481 patients surgically treated for squamous cell carcinoma of the head and neck (SCCHN) who had immunohistochemical data for N-ras. Advanced stages of disease were strongly related to the staining for N-ras in tumour cells (P = 0.0031). The stage of disease was inversely related to duration of survival (P = 0.0017). Initial statistical evaluation revealed an apparent correlation between survival and N-ras staining. However, duration was found to be independent of the level of N-ras. The illusory relationship initially was a result of the confounding effect of the stage of disease.

Adult↗
PubMed1996

Benign and malignant gynecologic disease: clinical importance of fluid and peritoneal enhancement in the pelvis at MR imaging.

PURPOSE: To correlate magnetic resonance (MR) imaging findings of pelvic fluid, peritoneal enhancement, and peritoneal nodules with the presence of benign or malignant pelvic disease. MATERIALS AND METHODS: Pelvic MR imaging findings in 87 women (mean age, 46 years) who subsequently underwent surgery were retrospectively reviewed. Phased-array multicoil, axial spin-echo T1-weighted MR images and axial fast spin-echo T2-weighted images were obtained. The largest pelvic fluid pocket was measured on the T2-weighted images in three orthogonal dimensions. Peritoneal enhancement and nodules were evaluated on gadolinium-enhanced MR images in 54 women. RESULTS: Pelvic fluid was shown in 21 of 25 patients with malignant neoplasms and 48 of 62 patients with benign disorders. Larger fluid pockets were associated with malignancy rather than with benign disorders, but there was substantial overlap. Use of peritoneal enhancement to diagnose peritoneal spread of tumor had a sensitivity, specificity, accuracy, and positive predictive value of 92% (11 of 12), 86% (36 of 42), 87% (47 of 54), and 65% (11 of 17), respectively. Use of peritoneal nodules for peritoneal spread had a higher specificity (90% [38 of 42]) and positive predictive value (69% [nine of 13]), although the sensitivity was lower (75% [nine of 12]). CONCLUSION: Large peritoneal fluid pockets are moderately predictive of malignancy or peritoneal spread of tumor. Peritoneal enhancement and enhancing peritoneal nodules are more sensitive and more specific.

Ascitic Fluid↗
PubMed1996

Single particle tracking of cell-surface HLA-DR molecules using R-phycoerythrin labeled monoclonal antibodies and fluorescence digital imaging.

The mobility of cell surface MHC molecules and their ability to form dynamic associations may be related to the physiological status of the cell and to the potential to bind effector T lymphocytes. To investigate these properties, we have prepared HLA DR specific monoclonal antibodies coupled in a 1:1 mole ratio to the fluorescent phycobiliprotein, R-phycoerythrin (PE). We show that these small particles can be sequentially imaged using a cooled slow-scan charge coupled device camera and hence can be used for single particle tracking experiments. We have applied this technique to investigate the movements of HLA DR molecules on fibroblasts transfected with human DR alpha and DR beta genes. PE-IgG was bound to the transfected fibroblasts and particle tracks were obtained by sequential imaging over a period of typically 30 minutes. Analysis of particle tracks revealed the presence of directed motion and domain-limited diffusion in addition to random diffusion. The contributions of these three types of motion showed cell to cell variability. Velocities of directed motion were of the order of 2 nm second-1 whilst domain diameters were in the range 200-800 nm. Diffusion coefficients for random diffusion were in the range 1 x 10(-13)-5 x 10(-12) cm2 second-1. The higher mobilities were observed for the lower intensity fluorescent spots, which possibly correspond to images of single particles. Much lower mobility was observed with a cell where the spot intensities were approximately double that of the lower intensity spots. These spots could be images of double particles implying the association of at least two HLA DR alpha beta dimers. These data are relevant to the study of MHC class II cell surface redistribution and antigen presentation in specific immunity.

Antibodies, Monoclonal↗
PubMed1995

An STS-based map of the human genome.

A physical map has been constructed of the human genome containing 15,086 sequence-tagged sites (STSs), with an average spacing of 199 kilobases. The project involved assembly of a radiation hybrid map of the human genome containing 6193 loci and incorporated a genetic linkage map of the human genome containing 5264 loci. This information was combined with the results of STS-content screening of 10,850 loci against a yeast artificial chromosome library to produce an integrated map, anchored by the radiation hybrid and genetic maps. The map provides radiation hybrid coverage of 99 percent and physical coverage of 94 percent of the human genome. The map also represents an early step in an international project to generate a transcript map of the human genome, with more than 3235 expressed sequences localized. The STSs in the map provide a scaffold for initiating large-scale sequencing of the human genome.

Animals↗