Hyaluronan-phosphatidylethanolamine polymers form pericellular coats on keratinocytes and promote basal keratinocyte proliferation.

Aged keratinocytes have diminished proliferative capacity and hyaluronan (HA) cell coats, which are losses that contribute to atrophic skin characterized by reduced barrier and repair functions. We formulated HA-phospholipid (phosphatidylethanolamine, HA-PE) polymers that form pericellular coats around cultured dermal fibroblasts independently of CD44 or RHAMM display. We investigated the ability of these HA-PE polymers to penetrate into aged mouse skin and restore epidermal function in vivo. Topically applied Alexa(647)-HA-PE penetrated into the epidermis and dermis, where it associated with both keratinocytes and fibroblasts. In contrast, Alexa(647)-HA was largely retained in the outer cornified layer of the epidermis and quantification of fluorescence confirmed that significantly more Alexa(647)-HA-PE penetrated into and was retained within the epidermis than Alexa(647)-HA. Multiple topical applications of HA-PE to shaved mouse skin significantly stimulated basal keratinocyte proliferation and epidermal thickness compared to HA or vehicle cream alone. HA-PE had no detectable effect on keratinocyte differentiation and did not promote local or systemic inflammation. These effects of HA-PE polymers are similar to those reported for endogenous epidermal HA in youthful skin and show that topical application of HA-PE polymers can restore some of the impaired functions of aged epidermis.

Social Support Contributes to Outcomes following Distal Radius Fractures.

Background. Distal radius fractures are the most common fracture of the upper extremity and cause variable disability. This study examined the role of social support in patient-reported pain and disability at one year following distal radius fracture. Methods. The Medical Outcomes Study Social Support Survey was administered to a prospective cohort of 291 subjects with distal radius fractures at their baseline visit. Pearson correlations and stepwise linear regression models (F-to-remove 0.10) were used to identify whether social support contributes to wrist fracture outcomes. The primary outcome of pain and disability at one year was measured using the Patient Rated Wrist Evaluation. Results. Most injuries were low energy (67.5%) and were treated nonoperatively (71.9%). Pearson correlation analysis revealed that higher reported social support correlated with improved Patient Rated Wrist Evaluation scores at 1 year, r(n = 181) = -0.22, P < 0.05. Of the subscales within the Social Support Survey, emotional/informational support explained a significant proportion of the variance in 1-year Patient Rated Wrist Evaluation scores, R (2) = 4.7%, F (1, 181) = 9.98, P < 0.05. Conclusion. Lower emotional/informational social support at the time of distal radius fracture contributes a small but significant percentage to patient-reported pain and disability outcomes.

Do all hemochromatosis patients have the same origin? An analysis of mitochondrial DNA and Y-DNA.

BACKGROUND: Mitochondrial DNA (mtDNA) and Y-DNA analysis have been widely used to predict ancestral origin. Genetic anthropologists predict that human civilizations may have originated in central Africa one to two million years previously. Primary iron overload is not a common diagnosis among indigenous people of northern Africa, but hereditary hemochromatosis is present in approximately one in 200 people in northern Europe. MtDNA analysis has the potential to determine whether contemporary hemochromatosis patients have an ancient ancestral linkage. METHODS: DNA was obtained from buccal smears for mtDNA and Y-DNA analysis. Y-DNA analysis included examination of 20 short tandem repeat markers on the Y chromosome. Analysis of mtDNA involved sequencing of the HVR-1 genetic sequence (nucleotides 16001 to 16520) and was compared with the Cambridge Reference Sequence. MtDNA ancestral haplotypes were predicted from the analysis of the HVR-1 sequence. RESULTS: Twenty-six male C282Y homozygotes were studied. There were 28 polymorphisms present in the HVR-1 sequence of these participants. The most common polymorphism was present at position 16519 in 15 participants and at position 16311 in eight participants. There were 12 different ancestral haplotypes predicted by mtDNA analysis, with the K haplotype being present in five participants. Y-DNA analysis revealed eight different haplotypes, with R1b being found in 11 of the 26 participants. CONCLUSION: Analysis of mtDNA and Y-DNA in 26 hemochromatosis patients suggested that they did not all originate from the same ancestral tribe in Africa. These findings were consistent with the theory that the original hemochromatosis mutation occurred after migration of these ancestral people to central Europe, possibly 4000 years previously.

Muscle strength and fatigue in patients with generalized myasthenia gravis.

Myasthenia gravis (MG) is characterized by fatigue and fluctuating muscle weakness resulting from impaired neuromuscular transmission (NMT). The objective of this study was to quantify, by direct measurement of muscle force, the strength and fatigue of patients with MG. A maximal voluntary isometric contraction protocol of shoulder abductors was used in conjunction with conventional fatigue and disease-severity instruments. Results from patients with (D-MG) and without (ND-MG) decrement on repetitive nerve stimulation (RNS) of the spinal accessory and axillary nerves were compared with healthy controls. Patients with MG reported greater fatigue than controls. Muscle strength was lowest in the D-MG group, followed by the ND-MG group and controls. Normalized shoulder abduction fatigue and recovery values did not differ between the D-MG and ND-MG groups or controls. The RNS decrement appears to relate best to disease severity and muscle weakness but not to objective measures of fatigue in this population.