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.

Dietary health and CVD: implications for dietary policy in England.

CVD is a major burden on the health system in the UK. On average, diets are not aligned with current dietary recommendations, including those for salt, saturated fat, fibre, fruit and vegetables. Obesity prevalence is high and the majority of the population is consuming more energy than required. Addressing these issues would reduce the burden of CVD and help reduce inequalities in health. There is currently a range of policy interventions in place in England designed to help improve diets and reduce obesity, which in turn should help reduce the risk of CVD. Further actions may be needed in the long term to deliver sustained improvements to diet and health.

High-energy, high-fat lifestyle challenges an Arctic apex predator, the polar bear.

Regional declines in polar bear (Ursus maritimus) populations have been attributed to changing sea ice conditions, but with limited information on the causative mechanisms. By simultaneously measuring field metabolic rates, daily activity patterns, body condition, and foraging success of polar bears moving on the spring sea ice, we found that high metabolic rates (1.6 times greater than previously assumed) coupled with low intake of fat-rich marine mammal prey resulted in an energy deficit for more than half of the bears examined. Activity and movement on the sea ice strongly influenced metabolic demands. Consequently, increases in mobility resulting from ongoing and forecasted declines in and fragmentation of sea ice are likely to increase energy demands and may be an important factor explaining observed declines in body condition and survival.

Urinary excretion of beta-aminopropionitrile and cyanoacetic acid.

Human serum did not convert beta-aminopropionitrile (BAPN) to the deaminated, nonlathyrogenic metabolite, cyanoacetic acid (CAA). Instead, its enzymic activity for oxidizing benzylamine was inhibited by BAPN (I50 = 2 X 10(-3) M). BAPN was found in the urine within one hour of oral administration. Oral 250 mg BAPN at 6-hr intervals each day for 21 days resulted in urinary BAPN recoveries approximating 16% of the total dose. BAPN was not detected in urine in specimens collected later than 7 hr after cessation of BAPN dosage. Urinary CAA appeared more slowly than BAPN and increased gradually to approximately three times that of urinary BAPN. After BAPN was discontinued, there was prolonged urinary excretion of BAPN-derived CAA. These along with earlier findings in experimental animals suggest that unexcreted BAPN is sequestered in tissues where it is metabolized to CAA before slowly released.

Morphologic aspects of experimental esophageal lye strictures. II. Effect of steroid hormones, bougienage, and induced lathyrism on acute lye burns.

Among 77 dogs surviving standardized transmural esophageal lye injury for at least 2 weeks and as long as 12 weeks, 24 were untreated, 26 received corticosteroids and bougienage (S&B), and 27 received only the lathyrogen beta-aminoproprionitrile (BAPN). Stricture frequency was reduced markedly and significantly in the S&B and BAPN groups when compared to the controls (p less than 0,01). Strictures resulted from inward circumferential remodeling of all mural layers, not proliferating bulky scar tissue, and persistent ulceration was apparently not an influential factor in any group. The S&B dogs invariably showed reduction of the internal or mucosal length of the injured segment as compared to the outer length; these relations were quite variable in the other two groups so that mean internal shortening was significantly greater (p less than 0.01) in the S&B group. Marked mural thinning in the injured zone was present in all three groups but was most frequent in the BAPN-treated animals. The major conclusion is that BAPN-induced changes in the physical properties of reparative tissue can increase the ultimate caliber of an injured hollow viscus without resort to mechanical bougienage. In addition, the data suggest that wound contraction may play a role in stricture formation in this model.

Dimethylnitrosamine-induced hepatic cirrhosis: a new canine model of an ancient human disease.

1. A new canine model of hepatic cirrhosis, created by intermittent, oral administration of dimethylnitrosamine, a specific hepatotoxin, is described. 2. DMNA-induced cirrhosis is stable or progressive after discontinuing the toxin, is associated with significant physiological abnormalities which correlate with severity of histological lesions, and can be produced rapidly. 3. Histological, biochemical, and physiological abnormalities associated with DMNA-induced cirrhosis resemble many features of hepatic cirrhosis in man. Data suggest that this model may be useful in studying other parameters of this complex disorder.

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.

A neuromuscular basis for development of indirect inguinal hernia.

Specialized portions of the transversus abdominus muscles act on the internal inguinal rings and produce a closure mechanism during voluntary abdominal muscular activity. Abdominal muscular contractions may have a protective influence against development of indirect inguinal hernia. It follows, therefore, that injury or inactivation of this mechanism may be an etiologic factor in the development of indirect inguinal hernia. One cause of injury to this mechanism is by denervation and regional muscle paralysis occurring during a surgical procedure. Surgical denervation appears to have caused an indirect inguinal hernia in one of the authors.

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.

Administration of beta-aminopropionitrile to human beings with urethral strictures: A prelimary report.

(1) No toxic signs or symptoms and no unusual laboratory determinations were observed in five patients with posterior urethral strictures treated by dilatation of the urethra and administration of 1 gm per day of beta-aminopropionitrile (BAPN) for twenty-one days. (2) Patients treated with 1 gm daily of BAPN for twenty-one days showed an increase in cold saline-extractable and acid-extractable collagen in proplast sponge-collected and dermal scar tissue comparable with that reported previously after doses of 3 to 5 gm of BAPN daily. (3) Significant reduction in the breaking strength of newly synthesized connective tissue was observed in patients treated with BAPN. (4) None of the patients in this study showed abnormalities in net collagen synthesis or in synthesis of noncollagenous protein. (5) The difference in the results of this study and two previous trials of BAPN in human beings which were discontinued because of toxic and or hypersensitivity signs and symptoms is hypothesized to be the result of development of highly purified BAPN fumarate.

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.

Pharmacological control of surgical scar tissue.

Pharmacological control of unwanted scar tissue theoretically is possible in human beings and has been proven to be practical and effective treatment in laboratory animals. The most advanced research involves prevention of the development of helical structure and transport of collagen by administration of proline analogues and controlled induction of lathyrism by administration of Beta-aminopropionitrile. The toxicity of proline analogues has prevented human testing; BAPN presently is being tested or has been tested in patients with scleroderma, flexor tendon adhesions, posterior urethral strictures, and surface keloids. At this time, highly purified BAPN appears generally non-toxic and is capable of exerting a higly selective and significant lathyrogenic effect on the healing wound. The combination of BAPN and other drugs, such as Colchicine, which increases collagenolytic activity, probably will make safe control of clinical properties of scar tissue possible within the next 24 months.

Dupuytren's disease: controversial aspects of management.

Surgical literature is replete with descriptions of Dupuytren's contracture and the various operations which surgeons have utilized to correct contractures of the palmar fascia. All that is worthy of presentation now are the unknown factors or frontiers of our knowledge. Etiology and control of major complications such as pain, joint stiffness, and recurrence are the frontiers which seem most intriguing to the author. The first step in scientific exploration of these areas is to form a hypothesis which takes into account all of the known factors. In this treatise, the author has stated a hypothesis for each of the frontiers. One hypothesis is that genetic predisposition for selective hyperkinetic collagen metabolism in the palm may be a biological counterpart to the condition found in transversalis fascia in patients with direct inguinal hernia. A hypothesis for pain syndromes is based upon general visceral afferent impulses striking a preconditioned central tract or sensitized central receptor. Joint stiffness has been attributed to the protracted release of polypeptides which change the electrical charge on crystalline protein and result in binding of water which then leads to secondary remodeling of joint structures. Recurrence or persistence of Dupuytren's contracture has been considered to be the result of a persistent inductive phenomenon by cells in the deepest layer of the dermis. Brief arguments supporting these hypotheses as being more tenable now than most others have been presented. For the most part such deductions have been based primarily upon the argument that no other hypothesis presently before us takes into account all of the available data or clinical observations, meager as they may be. Prejudice for surgical biology as a means of enlightenment, intuition, and, at times, empirical reasoning has been admitted in an attempt to stimulate imagination. The rest is left to the reader.

Biological basis for management of benign disease of the breast. The case against subcutaneous mastectomy.

The biology of breast disease abnormalities which are primarily the result of hormonal imbalance, and the action of hormones upon breast tissue are discussed. An understanding of the basic biological principles makes it possible to manage these patients more accurately. An accurate diagnosis is necessary to predict what changes will occur with the progression of time. Our reservations about subcutaneous mastectomy are stated.

Escherichia coli O157:H7: etiology, clinical features, complications, and treatment.

In recent years, Escherichia coli (E. coli) O157:H7 has developed into an emerging cause of foodborne illness. It has been identified as the leading cause of post-diarrheal hemolytic-uremic syndrome (HUS) and acute renal failure in infancy and childhood. This article examines, the etiology, clinical features, complications, and treatment of this illness. Prevention strategies are also presented as well as a disaster management case study.

Drug resistant organisms and their implications for the outpatient dialysis setting.

Ever since antibiotics have been used to combat infection, resistance to them has also developed. The elderly and immunosuppressed populations found in today's dialysis facility comprise a group at risk for acquiring infection caused by drug resistant organisms. By utilizing antibiotics prudently and developing infection control strategies based on the disease/organism epidemiology, mode of transmission and individualized needs of the patient as well as the care setting, the proliferation of drug resistant organisms may be curtailed.