Wet degradation of keratin proteins: linking amino acid, elemental and isotopic composition.

RATIONALE: Archaeological keratin samples are increasingly the subject of palaeodietary, provenancing and dating studies. Keratin samples from wet archaeological contexts are microbiologically and chemically degraded, causing differential diagenesis of protein structures in hair fibres. The effects of these processes on the analytical parameters of interest are currently unknown. METHODS: This study examined the impact of degradation of wool fibres on isotopic (δ(13)C, δ(15)N, un-exchangeable δ(2)H and δ(18)O values) composition. It compared two models of archaeological protein degradation in wet burial environments: (1) short term (up to 8 years) experimental burial in three contrasting soil environments; and (2) laboratory wet conditions, in which elevated temperature (80 °C, 110 °C, and 140 °C) and pressure simulated longer exposure. Elemental and amino acid (AA) composition were also measured. RESULTS: In experimentally soil-buried samples, AA, elemental and isotopic composition changes were small, despite extensive macroscopic alteration. Isothermally heated samples showed preferential loss of hydrophilic AAs (Asx, Glx, Ser, Gly) from wool residues, with depletion in (2)H and (18)O at higher temperatures (up to -73‰ change in δ(2)H and -2.6‰ in δ(18)O values). The δ(13)C and δ(15)N values showed little change except in densely pigmented samples at low temperatures only. Samples dyed with madder/alum were better preserved than undyed samples. CONCLUSIONS: Diagenesis in experimentally soil-buried wool textiles was consistent with microbiological, non-protein-selective activity, in contrast to highly AA-selective hydrolytic behaviour under laboratory wet conditions. Changes in δ(2)H and δ(18)O values were correlated with degree of AA change, but the δ(13)C and δ(15)N values were not. The results contribute to a baseline for interpreting analytical data from archaeological hair samples preserved by burial in wet environments.

Major ambulatory surgery of the plastic surgical patient.

In the final analysis, a patient who does not require any more in the way of postoperative nursing care than bed rest and administration of food, water, and pain medication should be able to have surgery in an outpatient facility as safely and successfully as in an inpatient facility. A large general plastic surgery practice in an ambulatory surgical center creates unique problems, but most of these problems are solvable and have not prevented most plastic surgeons from conducting an ever increasing volume of their work in the ambulatory setting.

Internal reconstruction of the pelvic floor for recurrent groin hernia.

Repeated recurrence of groin hernia is more than an anatomical derangement that any trained surgeon can correct. Attempts to improve results include application of local patches of Marlex. There are two reasons (one theoretical and one practical) why a local synthetic patch may not be as useful as total reconstruction of endopelvic fascia with a biologically active, as well as structurally strong, living material. Such a restoration can be accomplished with the entire fascia lata from one thigh utilized as a free graft extending from one pelvic wall to the other and from the symphysis to the pubic rami. The practical advantage of a single sheet of fascia extending across the pelvic floor (like an airplane wing) is that frequent medial recurrences are eliminated because there is no medial edge under which peritoneum can protrude. The theoretical advantage of a biologically active graft is based upon animal data revealing the inductive capacity of fascia in stimulating net collagen synthesis and deposition. Thirteen patients with multiple recurrences following conventional repair of groin hernia have been reconstructed with large fascia lata grafts restoring the entire endopelvic floor. Over a 5-year period no recurrences have been detected. A technique for removing the entire fascia lata from one thigh through a single transverse incision will be shown. There have not been any donor site complications and there is no disability caused by removing the fascia.

Preperitoneal abdominal wound repair: incidence of dehiscence.

Preperitoneal abdominal wound repair in 100 consecutive patients who required midline laparotomy resulted in one case of wound dehiscence. The risk of dehiscence did not increase with the use of vertical midline abdominal incisions repaired without inclusion of the peritoneum. Avoidance of suture penetration of the peritoneum may result in a reduction in postoperative adhesions and intestinal obstruction without increasing the risk of wound dehiscence.

Control of wound healing and scar formation in surgical patients.

Research in wound-healing biology has reached the developmental or practical application stage in the following major areas: reduction of liver collagen, prevention of secondary remodeling of peritoneal fibrous adhesions to produce tendinous bands that cause mechanical intestinal obstruction, reduction in the amount of scar tissue on the surface of the skin, alteration of mechanical properties of restricting a scar on gliding surfaces, and prevention of conduit stenosis after a circumferential internal injury. Pharmacologic agents, such as beta-aminopropionitrile, penicillamine, and colchicine, are being used as adjuvants to familiar surgical techniques. Control of collagen deposition and collagenolysis in the eye, lung, kidney, and around joints that are affected by rheumatoid arthritis will be possible in the next few years.

Pharmacologic control of surface scarring in human beings.

A hypothetical basis for control of surface scar in human beings is: lathyrism produces poorly cross-linked collagen in healing wounds; poorly corss-linked collagen is more susceptible to digestion by tissue collagenase than is normally cross-linked collagen; and colchicine stimulates tissue collagenase activity. Therefore, treatment of patients with abnormal deposits of surface scar by excising the scar, inducing lathyrism, and administering colchicine should tend to correct abnormal balance between collagen synthesis and collagenolysis and result in a small scar with improved physical properties. Ten patients with massive keloids, resistant to conventional therapy by excision, grafting, and/or intralesional injection of steroids, have been treated by excising the keloid, grafting the defect, inducing lathyrism with Beta aminopropionitrile fumurate or penicillamine and administering colchicine. Patients were followed for 18 months to five years. No toxicity or untoward side effects from therapy were observed. No patients developed recurrent keloids while undergoing treatment. All patients showed some change in the amount of scar which persisted during the period of study. This data supports the hypothesis that lathyrism and colchicine therapy exert a measurable beneficial effect on surface scar in human beings.