Developing a Novel Platelet-Rich Plasma-Laden Bioadhesive Hydrogel Contact Lens for the Treatment of Ocular Surface Chemical Injuries

Permanent injury to corneal limbal stem cells after ocular surface chemical and thermal injuries is a major cause of corneal blindness. In this study, a PRP-laden GelMA hydrogel contact lens is manufactured which is aimed to support the limbal niche after ocular surface insults thereby preventing limbal stem cell failure. GelMA with varying platelet-rich plasma (PRP) concentrations (5%, 10%, and 20%) is photopolymerized using a visible light crosslinking system followed by characterizations of mechanical properties, growth factor release, enzymatic degradation, and in vitro cytotoxicity. The addition of 10% PRP into 10% GelMA hydrogel precursor solution results in the highest tensile and compressive modulus (38 and 110 kPa, respectively) and burst pressure (251±37.66 mmHg). Degradation time varies according to the concentration of the collagenase enzyme tested (0, 2.5, 5, and 40 µg/mL) and is most prolonged with 20% PRP. EGF and TGF-β release profiles suggest an initial burst release followed by sustained release, most consistent in the 10% PRP sample. Although cell viability decreases on day 1, rapid recovery is observed and is approximately 120% after day 21. PRP-laden GelMA in the form of a contact lens may be a promising biomaterial-based treatment approach for the maintenance of limbal epithelial stem cells after ocular surface insults.

Bile duct carcinoma: trends in treatment in the nineties

Surgical resection provides the only known chance of cure for cholangiocarcinoma, and even then the 5-year survival is only 10 to 20%, and only one-third of patients are resectable for cure at the time of diagnosis. In recent years we have had considerable experience with endoscopic stenting to palliate common bile duct cancers. This has prompted us to evaluate our results for both endoscopic and surgical treatment of cholangiocarcinoma. From January 1990 through June 1999, we reviewed our endoscopic retrograde cholangiopancreatography registry and the hospital records for patients we treated for cholangiocarcinoma. Fifty patients were identified: 45 with cholangiocarcinoma and five with gallbladder cancer (who were excluded). The surgical group consisted of 16 patients: in 14 patients, resection for cure was possible whereas two had palliative procedures. There was one mortality (6%) and the median survival was 16 months. There have been no long-term surgical survivors, but 2 patients are alive at 24 months. We treated 29 patients with advanced disease with endoscopic stents (the endoscopic group) mainly for relief of obstructive jaundice. Six of 29 patients in the endoscopic group were critically ill and died in less than 4 weeks, whereas 23 patients who were in better condition survived for a mean of 10 months (range 2-84 months). We conclude that for common duct bile cancer surgical resection remains the treatment of choice but is applicable in only 30 to 35 per cent of cases. Endoscopic stenting effectively relieves jaundice and can provide long-term palliation comparable with surgical bypass; 12 of 29 patients in our endoscopic group survived 12 months or longer, and one is alive at 84 months after initial stenting.

Anatomic variations in sensory innervation of the hand and digits

Anatomic dissections under microscopic magnification were performed on 30 fresh cadaveric hands to depict the course and interconnections of the sensory nerves to the digits. The dissections included the median nerve, the ulnar nerve, the superficial branch of the radial nerve, the dorsal branch of the ulnar nerve, and the dorsal branch of the proper digital nerve. The communicating branches between the median and ulnar nerves in the palm were found in 20 of the 30 (67%) specimens. The dorsal branch of the proper digital nerve was found to arise at or proximal to the A1 pulley zone in 62% of the long digits, more proximally than previously reported. The dorsal sensory nerves (the terminal branch of radial or ulnar sensory nerves) extending to the nail bed area were found in 46% of the digits, thus confirming that sensory supply to the dorsum of the distal phalanx and nail bed also arises from the dorsal sensory nerves. Four types of palmar-dorsal interconnections, located in the middle of the proximal phalanx, were found in the digits but not in the thumb. The presence of these branches indicates dual innervation of the dorsal and palmar side of the distal areas of the digits. These anatomic findings may help hand surgeons interpret discrepancies in sensory loss after either dorsal or palmar injuries.