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Biomedical subjects

D T Huang

Publications and source records attributed to D T Huang.

26 records · Page 2Linked to original sources
PubMed1995

Combined chemoradiotherapy for locally advanced squamous cell carcinoma of the bulbomembranous urethra: a case report.

Patients with locally advanced squamous cell carcinoma of the bulbomembranous urethra fare poorly whether they undergo surgery or primary radiotherapy. Combined chemoradiotherapy has been used with encouraging results in the treatment of squamous cell carcinoma of the anal canal and esophagus, and limited reports suggest that this management may show promise in the control of squamous cell carcinoma of the urethra. We report good results in a man with locally advanced squamous cell carcinoma of the bulbomembranous urethra who underwent concomitant radiotherapy, mitomycin C and 5-fluorouracil. We encourage the use of this regimen in patients with urethral squamous cell carcinoma as well as the reporting of results.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Optical mapping of repolarization and refractoriness from intact hearts.

BACKGROUND: Heterogeneities of repolarization (R) across the myocardium have been invoked to explain most reentrant arrhythmias. The measurement of refractory periods (RPs) has been widely used to assess R, but conventional electrode and extrastimulus mapping techniques have not provided reliable maps of RPs. METHODS AND RESULTS: Guinea pig hearts were stained with a voltage-sensitive dye to measure fluorescence (F) action potentials (APs) from 124 sites with a photodiode array. AP duration (APD) was defined as the time between depolarization (dF/dt)max and R time points (ie, the time when AP returns to baseline or some percent thereof). However, R time points are difficult to determine because AP downstrokes are often encumbered by drifting baselines and motion artifacts, which make this definition ambiguous. In optical and microelectrode recordings, the second derivative of AP downstrokes is shown to contain an easily detected, unique local maximum. The correlation between the position of this maximum (d2F/dt2)max and R has been tested during altered AP characteristics induced by changes in cycle length, ischemia, and hypoxia. Under these various modifications of the AP, the time points of (d2F/dt2)max fell at 97.0 +/- 2.1% of recovery to baseline. Extrastimulus techniques applied to (1) isolated myocytes, (2) intact hearts, and (3) mathematical simulations indicated that (d2V/dt2)max coincided with the effective RPs of APs. The coincidence of RPs and (d2V/dt2)max was valid within 5 milliseconds, for resting potentials of -75 to -90 mV and extrastimuli three times threshold voltage. CONCLUSIONS: Thus, optical APs and (d2F/dt2)max can be used to map activation, R, and RPs with AP recordings from a single heartbeat.

Animals↗
PubMed1992

Stomal seeding by percutaneous endoscopic gastrostomy in patients with head and neck cancer.

Presented is the first known case of squamous cell carcinoma that developed at the site of a "pull" type percutaneous endoscopic gastrostomy stoma. The patient had advanced squamous cell carcinoma of the pharynx when the percutaneous endoscopic gastrostomy tube was placed. This article should serve as a warning of this potential complication. Alternate techniques and other precautionary methods are described.

Carcinoma, Squamous Cell↗
PubMed1992

Postoperative radiotherapy in head and neck carcinoma with extracapsular lymph node extension and/or positive resection margins: a comparative study.

In head and neck carcinoma, the finding of extracapsular lymph node extension and/or positive resection margins portends poor locoregional control and survival. The effectiveness of postoperative radiotherapy in these patients has been controversial due to insufficient studies comparing resected patients with those also receiving radiation. Between 1982 and 1988, 441 radical head and neck resections were performed at the Medical College of Virginia. Pathologic review of these cases identified 125 with extracapsular lymph node extension and/or positive resection margins. Of these, 43 had extracapsular lymph node extension only, 24 had both positive resection margins and extracapsular lymph node extension, and 58 demonstrated positive resection margins only. Surgery alone was performed in 71 of these patients while 54 cases received surgery and postoperative radiotherapy, (combined modality treatment) CMT. Radiotherapy doses ranged from 50 to 70 Gy. The surgery alone and combined modality treatment groups were comparable with respect to the distribution of positive resection margins and extracapsular lymph node extension. Slightly more CMT patients had clinical T4 disease compared with the surgery alone group (22% vs 14%). Slightly fewer combined modality treatment patients had clinical N0 necks than the surgery alone group (20% vs 29%). Multivariate analysis was performed with the variables T, N stages, radiotherapy, margin status, primary tumor sites, microscopic and macroscopic extracapsular lymph node extension, number of positive lymph nodes, number of nodes with extracapsular lymph node extension. Locoregional control was maintained at 5 years in 59% of the combined modality treatment group and 31% of the surgery alone group (p.0001). Subgroup analysis likewise reveals significant differences favoring the combined modality treatment group for positive resection margins only (49% vs 41%; p = .04), extracapsular lymph node extension only (66% vs 31%; p = .03) and extracapsular lymph node extension+positive resection margins (68% vs 0%; p = .001). Adjusted survival also shows a significant benefit of combined modality treatment vs surgery alone for the entire group (72% vs 41%; p = .001). Multivariate analysis revealed that the use of radiotherapy is a strongly favorable variable for local control and adjusted survival. Macroscopic extracapsular lymph node penetration and positive resection margins are unfavorable independent variables for local control. T-stage is the only variable predicting local control in the combined modality group. Extracapsular extension remains an important negative prognostic variable for survival in both treatment groups. In conclusion, this study demonstrates a locoregional control and survival benefit for postoperative radiotherapy in patients with the high risk pathologic findings of extracapsular lymph node extension and positive resection margins.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Y2K: effects on pacemaker and implantable defibrillator programmers.

All permanent pacemakers and implantable defibrillators (PPM/ICDs) will continue to function as programmed without regard to the date in the year 2000 (Y2K). All manufacturers contacted reassured us that some of these devices incorporate a day/year clock in the circuitry; however, these are not involved in sensing or delivering programmed therapy. Some manufacturers' device programmers will roll over to the year 2000 without any problems at all, whereas others may have difficulty with date and time stamping on printed reports. We tested 14 different types of PPM/ICD programmers for Y2K compliance using 8 tests. Five of the 14 models passed each test and were labeled at our institution with a green "Y2K" sticker to identify them as Y2K compatible and needing no special attention after December 31, 1999. The most common test failed was the ability to roll the date forward from December 31, 1999, with the programmer power off. Organizations should consider testing and replacing noncompliant device programmers or placing a red sticker with "Y2K" crossed out on noncompliant pieces. The red sticker alerts the advanced practice nurse or physician to the need to confirm the appropriate date and time in the programmer after startup in the year 2000 and before interrogating or programming any PPM/ICD, to avoid inappropriate date and time stamping on printed reports from that programmer.

Attitude of Health Personnel↗