Measuring telomerase activity for the early detection of cancer.

Telomeres are the terminal portions of chromosomes and consist of the repeated nucleotide sequence TTAGGG. Chromosomes lose a small amount of telomeric deoxyribonucleic acid (DNA) after each cell replication. A hypothetical function of telomeric DNA is to allow for a finite number of cell divisions without loss of functional genes. A second proposed function of telomeric DNA is to prevent undesirable interactions between chromosomal ends and cellular repair enzymes. In cells that maintain a proliferative capacity, such as stem cells and cancer cells, telomere length is maintained by the reverse transcriptase, telomerase. Virtually every major human malignancy has been evaluated for telomerase activity and approximately 80% to 90% have demonstrated the presence of telomerase. In this article we review the current assays available for telomerase detection and discuss their relative strengths and limitations.

Tire explosion injuries to the upper extremity.

We describe a protocol for treating tire explosion injuries to the hands on the basis of treatment of five cases over a 3-year period at Emory University Hospital. These high-energy wounds frequently require emergent initial debridement and stabilization, followed by complex soft tissue and skeletal reconstruction to maximize function. Data from all cases are summarized to show similarities among these injuries and differences in their response to treatment. We define the stages of treatment, emphasizing prevention, complete assessment, and early intervention, especially for limb-threatening conditions with fasciotomy, revascularization, thorough debridement, and rigid fixation. We also discuss the importance of aggressive therapy, close follow-up, and treatment of late complications. Functional reconstruction was achieved in each case, suggesting that our treatment protocol can be used successfully.

Comparative study of intraarterial and intravenous anticoagulants in microvascular anastomoses.

Using a rat femoral artery crush-avulsion model previously described by the authors (Rooks et al.: Microsurgery 14: 130-134, 1993), we analyzed the relative efficacy of intraarterially delivered anticoagulants against similar systemically administered intravenous anticoagulants with double blinded experimentation. The model uses a standardized crush of approximately 0.3 J and a standardized avulsion. This is followed by vascular stasis for 90 seconds after vessel repair. All rats were limited to 175 to 225 gm in weight to control vessel size. Urokinase, heparin sodium, and dextran (40,000 Dalton) were evaluated in this study. A statistically significant (p-value = 0.02) increase in urokinase efficacy was found with intraarterial delivery. (Patency rate increased from 40% to 100%). No advantage to intraarterial delivery was evident with either dextran or heparin. There was a dose related improvement in patency with heparin that was unaffected by delivery route. (Patency increased from 30% to 80% with a statistical p-value of 0.018.)

Processing two dimensions of nonspeech stimuli: the auditory-phonetic distinction reconsidered.

Nonspeech stimuli were varied along two dimensions--intensity and rise time. In a series of speeded classification tasks, subjected were asked to identify the stimuli in terms of one of these dimensions. Identification time for the dimension of rise time increased when there was irrelevant variation in intensity; however, identification of intensity was unaffected by irrelevant variation in rise time. When the two dimensions varied redundantly, identification time decreased. This pattern of results is virtually identical to that obtained previously for stimuli that vary along a linguistic and a nonlinguistic dimension. The present data, taken together with those from other studies using the same stimuli, suggest that the mechanisms underlying the auditory-phonetic distinction should be reconsidered. The results are also discussed in terms of general models of multidimensional information processing.