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Sequential Monitoring (sequential + monitoring)

Distribution by Scientific Domains

Medical Sciences	40%

Selected Abstracts

Sequential Monitoring of Burials Containing Large Pig Cadavers Using Ground-Penetrating Radar

JOURNAL OF FORENSIC SCIENCES, Issue 3 2006
John J. Schultz Ph.D.
ABSTRACT: Ground-penetrating radar (GPR) was used to monitor 12 pig burials in Florida, each of which contained a large pig cadaver. Six of the cadavers were buried in sand at a depth of 0.50,0.60 m, and the other six were buried at a depth of 1.00,1.10 m and were in contact with the upper surface of a clay horizon. Control excavations with no pig internment were also constructed as blank graves and monitored with GPR. The burials were monitored with GPR for durations of either 12,13 or 21,21.5 months when they were then excavated to correlate the decomposition state of the cadaver with the GPR imagery. Overall, cadavers in sand were easily detected for the duration of this study at 21.5 months, even when completely skeletonized. Conversely, in clay it became increasingly difficult to image the pig cadavers over the first year of burial, even when they still retained extensive soft tissue structures. [source]

Nonparametric Rank-Based Methods for Group Sequential Monitoring of Paired Censored Survival Data

BIOMETRICS, Issue 4 2000
Susan Murray
Summary. This research gives methods for nonparametric sequential monitoring of paired censored survival data in the two-sample problem using paired weighted log-rank statistics with adjustments for dependence in survival and censoring outcomes. The joint asymptotic closed-form distribution of these sequentially monitored statistics has a dependent increments structure. Simulations validating operating characteristics of the proposed methods highlight power and size consequences of ignoring even mildly correlated data. A motivating example is presented via the Early Treatment Diabetic Retinopathy Study. [source]

Clinical usage of the squamous cell carcinoma antigen in patients with penile cancer

INTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2007
Stavros Touloupidis
Background: We present our initial experience with the use of the squamous cell carcinoma (SCC) antigen (SCCAg) in 16 men with penile SCC (SCC group), in four men with condyloma acuminatum (benign group), and in 32 blood donors (control group). Methods: The SCCAg levels were measured at presentation and every 6 months (upper limit was 2 ng/mL). The mean follow-up time was 4 years. Results: All non-SCC patients had normal SSCAg serum levels in contrast with the SCC patients. The presence of nodal and/or distant metastases resulted in statistically significant higher SCCAg levels, both at presentation and during the follow-up. In patients undergoing lymph node dissection with elevated SCCAg levels prior to the procedure, there was a statistically significant decrease of the SCCAg levels after the operation. Conclusion: The SCCAg level could be a serum marker that holds promise for clinical use in penile SCC. Sequential monitoring of SCCAg level might indicate developing of nodal and/or distant metastases and could be useful in following the response to treatment. [source]

Dynamic T1-weighted monitoring of vascularization in human carcinoma heterotransplants by magnetic resonance imaging,

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2003
Fabian Kiessling
Abstract Studies on tumor angiogenesis and antiangiogenic therapies are commonly performed with tumor heterotransplants in nude mice. To monitor therapeutic effects, improved noninvasive analyses of functional data are required, in addition to the assessment of tumor volume and histology. Here, we report on sequential monitoring of vascularization of human squamous cell carcinomas growing as heterotransplants in nude mice using MRI. Using a custom-developed animal coil in a conventional whole-body 1.5 T MRI scanner, dynamic T1w sequences were recorded after i.v. injection of Gd-DTPA in tumors grown for 17, 21, 25, 29 and 33 days. Amplitude and the exchange rate constant (kep) were calculated according to a 2-compartment model, discriminating intravascular and interstitial spaces, and correlated with tumor size and histology. High-resolution imaging of small heterotransplants from 100 to 1,000 mm3 was achieved, clearly discriminating vital and necrotic areas. Preceding the development of necroses, which were hyperintense in T2w images and confirmed with histology, a local decrease of amplitude and kep values was observed. Significantly higher amplitudes were found in tumor periphery than in central parts, correlating well with the vascular pattern obtained by immunocytochemistry. Tumor size correlated negatively with amplitude, probably as a result of increasing necrotic areas, whereas the reason for the observed increase of kep value with tumor size remains unclear. These data demonstrate that dynamic MRI is an excellent method for noninvasive assessment of tumor vascularization in small animals using a clinical whole-body scanner with little technical modifications. This technique provides functional data characterizing essential features of tumor biology and is thus appropriate for monitoring antiangiogenic therapies. © 2002 Wiley-Liss, Inc. [source]