Dynamics of early stem cell recruitment in skin flaps subjected to ischemia reperfusion injury.

OBJECTIVE: Bone marrow-derived stromal cell (BMSCs) therapy improves survival of skin flaps subject to ischemia/reperfusion (I/R) injury. However, very little is known about the trafficking and distribution of BMSCs in post-ischemic skin tissue following intravenous administration. The aim of this study was to assess the behavior of BMSCs in post-ischemic skin flaps and to compare the magnitude and kinetics of accumulation of BMSCs and leukocytes following I/R. METHODS: Cutaneous flaps perfused by the inferior epigastric vessels were created in C57Bl6 mice. The flaps were subjected to 3.5h of ischemia followed by reperfusion. Wound healing and vascular perfusion were assessed in 3 groups of mice (sham, I/R, and I/R+BMSCs treatment) on days 3, 5, 7 and 14 post-reperfusion. The kinetics and magnitude of BMSCs and leukocyte recruitment were quantified in additional 2 groups (Sham and I/R) after I/R using intravital fluorescence microscopy at 2 and 4h after the intravenous injection of fluorescently labeled BMSCs. RESULTS: Wound healing after I/R was significantly enhanced in skin flaps of mice treated with BMSCs, compared to controls. The rolling velocity of BMSCs was higher compared to leukocytes both in control mice (32.4±3.7µm/s vs 24.0±2.2µm/s, p<0.05) and in I/R mice (34.6±3.8µm/s vs 20.2±2.3µm/s, p<0.005). However, the rolling velocity of both cell populations was not altered by I/R. The firm adhesion and transendothelial migration of BMSCs did not differ from the values detected for leukocytes for both control and I/R mice. CONCLUSIONS: The magnitude and kinetics of BMSCs recruitment in skin flaps subjected to I/R are not significantly different from the responses noted for leukocytes, suggesting that similar mechanisms may be involved in the recruitment of both cell populations following I/R.

A 14-year-old boy with extranodal natural killer cell lymphoma of the nose, nasopharynx, larynx, and trachea in remission 6years after primary diagnosis. A longitudinal case report.

Nasal type extranodal natural killer/T-cell lymphoma (ENKTL) is a rare lymphoma in the USA and Europe but endemic in East Asia and in areas of South and Central America. Clinically natural killer cell lymphomas are divided into three categories; nasal, non-nasal and aggressive lymphoma/leukemia subtypes. ENKTL, nasal type occurs in the nose and can extend to the upper aero-digestive tract as reported in this longitudinal case study. This is a longitudinal report of progress of a 14-year-old boy with ENKTL originating in the nasal cavity with subsequent extension and recurrence in the contralateral nose, nasopharynx, larynx and trachea presenting with varying degrees of respiratory problems and eventually, respiratory distress. Caregiver refusal of stem cell transplantation prompted an alternative diagnostic and therapeutic approach. Clinical course with recurrences, extensions and remissions over 6years with tailored endoscopic surgical treatment and radiochemotherapy is documented to present a guide in the multidisciplinary management of this rare disease.

Influence of body size and environmental temperature on carbon dioxide production by forest centipedes from southwestern North America.

We conducted a laboratory study to evaluate the mass and temperature dependence of carbon dioxide production by three dominant centipede species--Arctogeophilus umbraticus McNeill, Gonibius glyptocephalus Chamberlin, and Oabius sp.--from a montane forest in southwestern North America. We found that CO2 production (Q, microl/h) of resting, nonfasted individuals was related to body mass (M, mg live) and environmental temperature (T, K) as Q=e18.32M0.82e-0.49/kT, where e is the base of the natural logarithm and k is Boltzmann's constant (8.62x10(-5) eV/K). Our results indicated that the mass and temperature dependence of centipede metabolism is comparable with that of other arthropods. They also supported previous claims that centipede metabolic rate, for a given mass and temperature, is relatively low compared with other arthropods. Suggestions are given for using resulting metabolic rate equations in conjunction with data on abundance, body size, and environmental temperature to assess energy flux by centipede populations.