Enhanced flow-motion complexity of skin microvascular perfusion in Sherpas and lowlanders during ascent to high altitude.

An increased and more effective microvascular perfusion is postulated to play a key role in the physiological adaptation of Sherpa highlanders to the hypobaric hypoxia encountered at high altitude. To investigate this, we used Lempel-Ziv complexity (LZC) analysis to explore the spatiotemporal dynamics of the variability of the skin microvascular blood flux (BF) signals measured at the forearm and finger, in 32 lowlanders (LL) and 46 Sherpa highlanders (SH) during the Xtreme Everest 2 expedition. Measurements were made at baseline (BL) (LL: London 35 m; SH: Kathmandu 1300 m) and at Everest base camp (LL and SH: EBC 5,300 m). We found that BF signal content increased with ascent to EBC in both SH and LL. At both altitudes, LZC of the BF signals was significantly higher in SH, and was related to local slow-wave flow-motion activity over multiple spatial and temporal scales. In SH, BF LZC was also positively associated with LZC of the simultaneously measured tissue oxygenation signals. These data provide robust mechanistic information of microvascular network functionality and flexibility during hypoxic exposure on ascent to high altitude. They demonstrate the importance of a sustained heterogeneity of network perfusion, associated with local vaso-control mechanisms, to effective tissue oxygenation during hypobaric hypoxia.

Use of Protoporphyrin Fluorescence to Determine Clinical Target Volume for Non-melanotic Skin Cancers Treated with Primary Radiotherapy.

PURPOSE: Non-melanotic skin cancers remain the most commonly diagnosed cancers. Radiotherapy and surgery are the most common treatment options. Radiotherapy has a recurrence rate of up to 20% for basal or squamous cell cancers. One of the difficulties is to determine the extent of disease for poorly demarcated tumors. This study utilizes protoporphyrin (PpIX) fluorescence to provide information on the extent of subclinical disease for poorly demarcated tumors treated with radiotherapy. MATERIALS AND METHODS: For 33 patients, PpIX photo-delineation was used to determine the clinical target volume (CTV2), which was compared to current conventional margins used to account for microscopic disease. RESULTS: The use of PpIX photo-delineation demonstrated a significantly larger CTV of 15 mm compared to the conventional 10 mm (p = 0.03) for poorly demarcated lesions. A larger CTV was also demonstrated with PpIX photo-delineation for all basal cell carcinomas (13 mm, p = 0.03) as well as for non-nasal lesions (14 mm, p = 0.04). A trend towards an increased CTV was also noted for squamous cell carcinomas (16 mm, p = 0.19) and nasal primary sites (14 mm, p = 0.11). Nasal primary malignancies had multifocal PpIX uptake in 94% of cases. There was one case of local recurrence and one case of distant recurrence, with an average follow-up time of 22 months. CONCLUSIONS: The margins currently used to account for subclinical disease may underestimate the extent of microscopic spread for poorly demarcated tumors. Longer follow-up with larger pools of patients are necessary to determine if using PpIX photo-delineation translates into significantly improved clinical outcomes.

Reducing admission times in the endoscopy unit.

Pre-procedural admission of outpatients to a day-case endoscopy facility is time-consuming. Collecting and recording routine but necessary information distracts nurses from spending time that could be used to counsel patients. This study assessed whether patients can record some pre-procedural details and whether such self-recording quickens nurse admission times. A new admission document was devised and posted to patients. Patients completed personal/administrative details and information about drugs and allergies and brought the document with them when attending for outpatient endoscopy. Endoscopy nurses anonymously timed 100 admissions, 50 using the new admission form and 50 using the old admission form. Overall, the median (range) time to admit using the old form was 6 (3-15.5) min. Using the new form, the median time to admit was lower at 4 (0.5-10) min. No patient completing the new form reported any particular difficulties. An admission document that patients partially complete at home leads to a faster pre-procedural admission in the endoscopy unit. This allows more nursing time to discuss patients' anxieties and answer patient queries, helps to prevent delays and facilitates increased capacity in the endoscopy unit.