Biomedical subjects

Jeffrey Myers

Publications and source records attributed to Jeffrey Myers.

6 recordsLinked to original sources

PubMed2005

Placement of deep brain stimulator electrodes using real-time high-field interventional magnetic resonance imaging.

A methodology is presented for placing deep brain stimulator electrodes under direct MR image guidance. The technique utilized a small, skull-mounted trajectory guide that is optimized for accurate alignment under MR fluoroscopy. Iterative confirmation scans are used to monitor device alignment and brain penetration. The methodology was initially tested in a human skull phantom and proved capable of achieving submillimeter accuracy over a set of 16 separate targets that were accessed. The maximum error that was obtained in this preliminary test was 2 mm, motivating use of the technique in a clinical study. Subsequently, a total of eight deep brain stimulation electrodes were placed in five patients. Satisfactory placement was achieved on the first pass in seven of eight electrodes, while two passes were required with one electrode. Mean error from the intended target on the first pass was 1.0 +/- 0.8 mm (range = 0.1-1.9 mm). All procedures were considered technical successes and there were no intraoperative complications; however, one patient did develop a postoperative infection.

Brain↗

PubMed2005

Gene expression profiling identifies activating transcription factor 3 as a novel contributor to the proapoptotic effect of curcumin.

The antitumor effect of curcumin (diferuloylmethane) is well established. However, there have been no unbiased studies to identify novel molecular targets of this compound. We therefore undertook a gene expression profiling study to identify novel targets of curcumin. A cDNA array comprised of 12,625 probes was used to compare total RNA extracted from curcumin-treated and untreated MDA-1986 cells for differential gene expression. We identified 202 up-regulated mRNAs and 505 transcripts decreased > or =2-fold. The proapoptotic activating transcription factor 3 (ATF3) was induced >4-fold. Two negative regulators of growth control [antagonizer of myc transcriptional activity (Mad) and p27kip1] were induced 68- and 3-fold, respectively. Additionally, two dual-activity phosphatases (CL 100 and MKP-5), which inactivate the c-jun-NH2-kinases, showed augmented expression, coinciding with reduced expression of the upstream activators of c-jun-NH2-kinase (MEKK and MKK4). Of the repressed genes, the expression of Frizzled-1 (Wnt receptor) was most strongly attenuated (8-fold). Additionally, two genes implicated in growth control (K-sam, encoding the keratinocyte growth factor receptor, and HER3) as well as the E2F-5 transcription factor, which regulates genes controlling cell proliferation, also showed down-regulated expression. Considering its role in apoptosis, we determined the contribution of ATF3 to the antitumor effect of curcumin. Curcumin-treated MDA-1986 cells showed a rapid, dose-dependent increase in ATF3/mRNA protein. Moreover, expression of an exogenous ATF3 cDNA synergized with curcumin in inducing apoptosis. Thus, we have identified several putative, novel molecular targets of curcumin and showed that one, (ATF3) contributes to the proapoptotic effects of this compound.

Activating Transcription Factor 3↗

PubMed2004

A pilot study using scripted ventilation conditions to identify key factors affecting indoor pollutant concentration and air exchange rate in a residence.

A pilot study was conducted using an occupied, single-family test house in Columbus, OH, to determine whether a script-based protocol could be used to obtain data useful in identifying the key factors affecting air-exchange rate (AER) and the relationship between indoor and outdoor concentrations of selected traffic-related air pollutants. The test script called for hourly changes to elements of the test house considered likely to influence air flow and AER, including the position (open or closed) of each window and door and the operation (on/off) of the furnace, air conditioner, and ceiling fans. The script was implemented over a 3-day period (January 30-February 1, 2002) during which technicians collected hourly-average data for AER, indoor, and outdoor air concentrations for six pollutants (benzene, formaldehyde (HCHO), polycyclic aromatic hydrocarbons (PAH), carbon monoxide (CO), nitric oxide (NO), and nitrogen oxides (NO(x))), and selected meteorological variables. Consistent with expectations, AER tended to increase with the number of open exterior windows and doors. The 39 AER values measured during the study when all exterior doors and windows were closed varied from 0.36 to 2.29 h(-1) with a geometric mean (GM) of 0.77 h(-1) and a geometric standard deviation (GSD) of 1.435. The 27 AER values measured when at least one exterior door or window was opened varied from 0.50 to 15.8 h(-1) with a GM of 1.98 h(-1) and a GSD of 1.902. AER was also affected by temperature and wind speed, most noticeably when exterior windows and doors were closed. Results of a series of stepwise linear regression analyses suggest that (1) outdoor pollutant concentration and (2) indoor pollutant concentration during the preceding hour were the "variables of choice" for predicting indoor pollutant concentration in the test house under the conditions of this study. Depending on the pollutant and ventilation conditions, one or more of the following variables produced a small, but significant increase in the explained variance (R(2)-value) of the regression equations: AER, number and location of apertures, wind speed, air-conditioning operation, indoor temperature, outdoor temperature, and relative humidity. The indoor concentrations of CO, PAH, NO, and NO(x) were highly correlated with the corresponding outdoor concentrations. The indoor benzene concentrations showed only moderate correlation with outdoor benzene levels, possibly due to a weak indoor source. Indoor formaldehyde concentrations always exceeded outdoor levels, and the correlation between indoor and outdoor concentrations was not statistically significant, indicating the presence of a strong indoor source.

Air Pollution, Indoor↗

PubMed2004

Airway-centered interstitial fibrosis: a distinct form of aggressive diffuse lung disease.

We describe 12 patients with a form of interstitial lung disease characterized pathologically by small airway-centered interstitial fibrosis and metaplastic bronchiolar epithelium extending around and often linking fibrotic and sometimes heavily muscularized bronchioles. Clinically, patients presented with chronic cough and progressive dyspnea. One was a current light smoker and two were ex-smokers. In 8 patients, a history of possible inhalational exposures, including wood smoke, birds, cotton, pasture, chalk dust, agrochemical compounds, and cocaine use, was elicited. Pulmonary function tests showed moderate to severe physiologic abnormalities, in most instances indicating a restrictive lung disease with decreased peripheral flow rates. Chest radiographs revealed predominantly diffuse reticulonodular infiltrates in the central lung fields, with thickening of the bronchial walls and decreased lung volumes. Chest computed tomography demonstrated peribronchovascular fibrosis and interstitial thickening. Bronchoalveolar lavage showed a mild increase in lymphocytes in 4 subjects. Patients were treated with corticosteroids and bronchodilators. Follow-up data were available in 10 patients. In 5 patients, the disease progressed and 4 of them died. Two patients remained stable and 3 improved or healed. We propose that these findings represent a distinct airway-centered disease that mostly behaves as an interstitial lung disease and may exhibit a poor outcome.

Adult↗

PubMed2002

Phase II study of induction chemotherapy with paclitaxel, ifosfamide, and carboplatin (TIC) for patients with locally advanced squamous cell carcinoma of the head and neck.

BACKGROUND: This Phase II trial was conducted to determine the response rate, particularly of the primary sites, tolerability, and toxicity of induction chemotherapy of paclitaxel, ifosfamide, and carboplatin for patients with previously untreated locally advanced squamous cell carcinoma of the head and neck (SCCHN). We also hypothesized that improved complete response (CR) rates with the induction chemotherapy may render better survival rates with subsequently delivered definitive local treatment. METHODS: All eligible patients with locally advanced SCCHN received two courses of induction chemotherapy and underwent repeated head and neck examination and computed tomography or magnetic resonance imaging scans. If the patients achieved responses (CR or partial [PR]), they received two more courses of chemotherapy before undergoing definitive local treatment. Induction chemotherapy consisted of paclitaxel (T; 175 mg/m(2) in a 3-hour infusion) on Day 1, ifosfamide (I; 1000 mg/m(2) in a 2-hour infusion) on Days 1-3 with intravenous mesna (200 mg/m(2) before and 400 mg/m(2) after ifosfamide), and carboplatin (C) using the Calvert formula for the area under the plasma concentration-versus-time curve of 6 on Day 1, repeated every 3-4 weeks. Prophylactic hematopoietic growth factors or antibiotics were not used in this study. Definitive local treatment was given based on the investigators' preference. RESULTS: Fifty-four patients were registered and 52 patients were assessable for response to induction chemotherapy; 2 were not evaluable. After four courses of induction chemotherapy, the CR rates of the primary and lymph node sites were 60%, and 41%, respectively. For both primary and lymph node sites, there were 31% CRs and 50% PRs with an overall response rate of 81%. Five (9%) patients developed neutropenic fever, all of whom recovered with antibiotic therapy. Two (4%) patients had infection without neutropenia and recovered without any complication. Grade 3/4 thrombocytopenia and anemia occurred in three (6%) and four (7%) patients, respectively. Grade 3/4 fatigue developed in four (7%), arthralgia/myalgia in two (4%), peripheral neuropathy in two (4%), and orthostatic hypotension in two (4%) patients. One patient died of severe anaphylaxis although a maximized resuscitation effort was made. With a median follow-up of 22 months, the organ preservation rate was about 81% (42 of 52 patients). Although survival rates were not primary end points in this study, with a median follow-up of 22 months, 43 (83%) patients are still alive. Overall 1 and 2-year survival rates were 88% and 82%, respectively. Disease-free 1 and 2-year survival rates were 88% and 77% respectively. CONCLUSIONS: TIC induction chemotherapy is associated with a high CR rate at the primary sites and with excellent survival and organ preservations rates with subsequently delivered definitive local therapy. The regimen was also well tolerated in the majority of patients. The TIC regimen should be developed further in the context of induction chemotherapy followed by concomitant chemoradiotherapy or with specific molecular targeted agents.

Adult↗

PubMed2002

Phase II and biologic study of interferon alfa, retinoic acid, and cisplatin in advanced squamous skin cancer.

PURPOSE: The purpose of this study was to test interferon alfa (IFNalpha), 13-cis-retinoic acid (13cRA), and cisplatin biochemotherapy in advanced squamous cell carcinoma (SCC) of the skin. PATIENTS AND METHODS: Patients with advanced skin SCC received IFNalpha (5 x 10(6) IU/m(2), subcutaneous injection, three times a week), 13cRA (1 mg/kg, orally, daily), and cisplatin (20 mg/m(2), intravenous injection, weekly) in a phase II trial. The growth inhibition, cell-cycle, and apoptosis activity of these agents was evaluated in two skin SCC cell lines (SRB1-m7 and SRB12-p9). RESULTS: Thirty-nine patients were enrolled. All were assessable for survival, 35 for response and toxicity (median follow-up was 38 months). The overall and complete response rates were 34% and 17%, respectively, with median durations of 9 and 35.4 months, respectively. The response rate was higher in locally advanced (67%) than metastatic (17%) disease (P =.007). Median survival was 14.6 months. One-, 2-, and 5-year survival rate estimates were 58%, 32%, and 21%, respectively. Toxicity included generally mild to moderate fatigue and mucocutaneous dryness, moderate to severe neutropenia (38%), and neutropenic fever (6%). There were no treatment-related deaths. In vitro growth inhibition and apoptosis effects of cisplatin were differential and inversely associated with those of retinoic acid and especially IFNalpha in two skin SCC lines. CONCLUSION: The rising incidence, morbidity, and mortality of advanced skin SCC are a major challenge for clinical oncologists. Combined 13cRA, IFNalpha, and cisplatin was clinically active in extensive locally advanced disease. Each agent had independent, non-cross-resistant biologic effects in vitro, which may account for the combination's clinical activity.

Adult↗