bluuebunny/crossref_metadata_2025 huggingface dataset:
Phakometric measurement of ocular surface radius of curvature and alignment: evaluation of method with physical model eyes
Authors: Barry Jean‐Cyriaque , Dunne Mark , Kirschkamp Thomas
Published: March 2003

Ophthalmophakometric measurements of ocular surface radius of curvature and alignment were evaluated on physical model eyes encompassing a wide range of human ocular dimensions. The results indicated that defocus errors arising from imperfections in the ophthalmophakometer camera telecentricity and light source collimation were smaller than experimental errors. Reasonable estimates emerged for anterior lens surface radius of curvature (accuracy: 0.02–0.10 mm; precision 0.05–0.09 mm), posterior lens surface radius of curvature (accuracy: 0.10–0.55 mm; precision 0.06–0.20 mm), eye rotation (accuracy: 0.00–0.32°; precision 0.06–0.25°), lens tilt (accuracy: 0.00–0.33°; precision 0.05–0.98°) and lens decentration (accuracy: 0.00–0.07 mm; precision 0.00–0.07 mm).
Validation of computer morphs for grading contact lens complications
Authors: Efron Nathan , Morgan Philip B. , Jagpal Ritu
Published: March 2003

An alternative to the use of printed grading scales for assessing the severity of contact lens‐induced ocular pathology is to use computer‐generated grading morphs. This technique involves manipulation of a continuously variable movie sequence until this matches the severity of the condition being observed. To validate the use of computer morphs, nine experienced optometrists were each invited to grade – to the nearest 0.1 increment – an image of each of 16 contact lens complications, using printed scales (Efron Grading Scales for Contact Lens Complications) and computer morphs (Efron Grading Morphs). This entire procedure was repeated approximately 2 weeks later, yielding a total data base comprising of 576 individual grading estimates. Good accuracy was achieved using computer morphs, as evidenced by the similarity between the mean of the test and retest grading estimates for the printed scales (2.8 ± 0.7) and the computer morphs (2.6 ± 0.8) (F1,8=2.7, p=0.14). There was no difference in median reliability between the printed scales (±0.41) and the computer morphs (±0.43) (Z=0.1, p=0.95). Computer morphs are thus considered to have been validated in view of their accuracy and reliability compared with printed scales. In addition, computer morphs offer considerable utility in terms of computer‐based clinical record keeping, teaching and learning, and clinical research.
A review of current knowledge on Electronic Vision Enhancement Systems for the visually impaired
Authors: Wolffsohn James S. , Peterson Rachael C.
Published: March 2003

Magnification can be provided to assist those with visual impairment to make the best use of remaining vision. Electronic transverse magnification of an object was first conceived for use in low vision in the late 1950s, but has developed slowly and is not extensively prescribed because of its relatively high cost and lack of portability. Electronic devices providing transverse magnification have been termed closed‐circuit televisions (CCTVs) because of the direct cable link between the camera imaging system and monitor viewing system, but this description generally refers to surveillance devices and does not indicate the provision of features such as magnification and contrast enhancement. Therefore, the term Electronic Vision Enhancement Systems (EVES) is proposed to better distinguish and describe such devices. This paper reviews current knowledge on EVES for the visually impaired in terms of: classification; hardware and software (development of technology, magnification and field‐of‐view, contrast and image enhancement); user aspects (users and usage, reading speed and duration, and training); and potential future development of EVES.
Practical and Validated Use of the Mini Nutritional Assessment in Geriatric Evaluation
Authors: Garry Philip J. , Vellas Bruno J.
Published: March 2003

Abstract In the past two decades, a number of geriatric assessment instruments have been developed to aid in the diagnosis and treatment of high‐risk elderly patients; tools are available to assess physical health, functional ability, psychological health, and socioeconomic and environmental changes with age. However, too little attention has been given to identifying those elderly who would benefit from early detection of malnutrition. The Mini Nutritional Assessment instrument was designed and validated in a series of studies to assess which geriatric patients are at risk for malnutrition. Nutrition assessment using this instrument takes approximately 15 minutes and can easily be administered by health professionals in geriatric clinics, and at admission to hospitals and/or nursing homes for early detection of patients who could be helped by nutrition intervention.
Usefulness of Nutrition Screening of the Elderly
Authors: Sahyoun Nadine R.
Published: March 2003

ABSTRACT Nutrition assessment is not a component of the routine health screening of the elderly, despite the important role that nutrition plays in the health status of the elderly population. Instruments are available to assess physical, cognitive, emotional, and social functions of the elderly, but each of these focuses on one aspect of health and does not necessarily reflect overall health status. More comprehensive tools are available to detect risk factors; however, they rely heavily on home visits by health professionals and do not include nutrition assessment. Before 1989, measures that included a nutrition component were indices to predict post‐surgical outcomes of hospitalized patients and were not aimed at screening community‐living people. The Nutrition Screening Initiative was formed as a multidisciplinary effort to promote nutrition screening and awareness and to incorporate nutrition into the healthcare system. The tools developed by the Nutrition Screening Initiative for use by the lay public and by health professionals include: the Determine Your Nutritional Health Checklist, which is an awareness and educational tool that can be self‐administered; a Level I Screen, which is a basic nutrition screen designed for use by social service and health professionals; and a Level II Screen, which provides more specific diagnostic information on nutrition status and is administered by health and medical professionals. Manuals were developed to assist the incorporation of screening tools into medical practice, health maintenance organizations, and home care agencies. Nutrition assessment and intervention are worthwhile endeavors that may add years of independent living and decrease medical expenditure for the elderly.
Red Wine in Moderation: Potential Health Benefits Independent of Alcohol
Authors: Cao Guohua , Prior Ronald L.
Published: March 2003

Moderate drinking of alcoholic beverages is associated with a lower risk of coronary heart disease. It is generally accepted that the ethanol itself is at least partially responsible for this association. However, whether red wine has any additional benefits is unclear since the epidemiologic studies addressing the additional effects of wine did not distinguish red from white. This review focuses on the differences between red wine and white wine with regard to their chemical components and biologic effects. Red wine contains considerably more flavonoids, particularly anthocyanins and proanthocyanidins, than white wine. Red wine, as well as its flavonoid constituents, has been shown to have antioxidant activities, to inhibit platelet aggregation, and to relax blood vessels. The data suggest that a moderate intake of red wine (1–2 drinks per day) may have potential health benefits independent of alcohol, and this warrants further clinical studies and epidemiologic investigations. In light of the dangers associated with alcohol consumption, it may be wise for some people to obtain the red wine flavonoids through consumption of fruits and vegetables that also contain these phytochemicals.
Intestinal Warfare: The Role of Short‐Chain Fructooligosaccharides in Health and Disease
Authors: Nadeau Daniel Allen
Published: March 2003

Short‐chain fructooligosaccharides (FOS) are a long‐studied functional food made up of a glucose molecule linked to between 2 and 4 fructose molecules and not significantly digested in the small intestine. Short‐chain FOS provide an energy source that is relatively specific for beneficial bacteria in the large intestine, with even small amounts leading to dramatic increases in bifidobacteria, which have a variety of health benefits in and of themselves. In addition, a predicable fall in pathogenic bacteria, such as clostridia, occurs as bifidobacteria increase. This has implications for several disorders, ranging from liver disease to antibiotic‐associated diarrhea to colon cancer. Short‐chain FOS are metabolized to short‐chain fatty acids, lowering pH in the colon. This facilitates calcium absorption, which may be beneficial for individuals with renal and liver disease, and has implications for colon cancer protection as well. Short‐chain fatty acids are the preferred substrate for colonic epithelial cells, which are potentially beneficial for those with ulcerative colitis risk. Other effects of short‐chain FOS include an effect on cholesterol metabolism through interference with enterohepatic circulation of cholesterol. Short‐chain FOS allow for a favorable shift in the balance of healthful vs harmful organisms, lowering colonic pH while providing an energy source for the gut, with significant implications for disease prevention.
Vitamin C Function and Status in Chronic Disease
Authors: Jacob Robert A. , Sotoudeh Gity
Published: March 2003

▪ Abstract Vitamin C is an essential dietary nutrient required as a co‐factor for many enzymes, and humans are among the few animals that lack the ability to synthesize the compound from glucose. The reduced form of the vitamin, ascorbic acid, is an especially effective antioxidant owing to its high electron‐donating power and ready conversion back to the active reduced form. Concentrations of the vitamin in body tissues and fluids are regulated through interactions of intestinal absorption, cellular transport, and excretion. The amount of vitamin C needed to prevent scurvy is very small and easily obtained in nearly all Western diets. There is great interest in the clinical roles of vitamin C because of evidence that oxidative damage is a root cause of, or at least associated with, many diseases. Population studies show that individuals with high intakes of vitamin C have lower risk of a number of chronic diseases, including heart disease, cancer, eye diseases, and neurodegenerative conditions. However, these results may simply reflect a more healthful diet or lifestyle for individuals with a high vitamin C intake. At present, data from controlled clinical trials have not established that higher intakes of vitamin C alone will help prevent chronic degenerative diseases. However, the evidence that ascorbic acid acts as an important antioxidant in many body tissues is convincing. The new higher Recommended Dietary Allowance (RDA) for vitamin C of 75 mg for women and 90 mg for men is, for the first time, based on the vitamin's role as an antioxidant as well as protection from deficiency. In healthy people, amounts greater than the RDA do not appear to be helpful. Vitamin C nutriture may be more important for people with certain diseases or conditions. High intakes of the vitamin are generally well tolerated; a Tolerable Upper Level was recently set at 2 g based on gastrointestinal upset that sometimes accompanies excessive intakes.
Soy Foods and Soybean Isoflavones and Menopausal Health
Authors: Messina Mark J.
Published: March 2003

Soybeans are a natural dietary source of isoflavones, which have estrogen‐like properties. Therefore, it is worthwhile to consider the implications for soy of the recently published findings of the Heart and Estrogen/Progestin Replacement Study (HERS) I/II and the Women's Health Initiative (WHI). The WHI found coronary heart disease (CHD) risk to be increased in women receiving hormone replacement therapy, and both studies found increases in venous thromboembolic disease in such women. Additionally, stroke and breast cancer risk were increased in the WHI, although risk of colorectal cancer and fracture was decreased. Because research suggests that it is the combination of estrogen plus progestin, and not estrogen alone, that increases breast cancer risk, soy seems unlikely to increase risk because it has no progestin activity. Similarly, there is no evidence to suggest that soy will increase venous thromboembolic disease or stroke; however, only limited data are available in this area. There are promising data suggesting that soy may decrease CHD risk, although studies conducted thus far have examined only markers of risk and not actual CHD events. Similarly, short‐term studies generally suggest that soy reduces bone loss in postmenopausal women; however, such effects have been noted primarily only at the spine, and longer‐term studies are needed. Finally, very limited human research suggests that soy may decrease colon cancer risk, but this is highly speculative. The results of HERS I/II and WHI suggest that soy may have some of the advantages, but not the disadvantages, of combined hormone replacement therapy (at least with respect to the specific hormones and doses used in the HERS I/II and WHI), but that large, long‐term intervention studies examining disease outcome are needed before definitive conclusions can be drawn. Nevertheless, the evidence warrants recommendations that menopausal women include soy in their diets.
Inhibition of elastase by a synthetic cotton‐bound serine protease inhibitor: in vitro kinetics and inhibitor release
Authors: EDWARDS J. VINCENT , BOPP ALVIN F , BATISTE SARAH , ULLAH ABUL J , COHEN I. KELMAN , DIEGELMANN ROBERT F , MONTANTE STEVEN J
Published: March 2003

A cotton‐bound serine protease inhibitor of elastase (fiber‐inhibitor) has been formulated for in vitro evaluation in chronic wound fluid. As a model to understand the properties of the inhibitor in wound dressings, the kinetic profile and in vitro release of the fiber‐inhibitor formulation have been examined. The elastase inhibitor N‐Methoxysuccinyl‐Ala‐Ala‐Pro‐Val‐chloromethylketone was modified onto cotton cellulose fibers and assayed as a colloidal system. Amino acid analysis and reversed phase high performance liquid chromatography were compared as semiquantitative methods to assess elastase inhibitor release from the cotton fibers. The kinetics of inhibition was assessed on treated fibers of synthetic dressings such that a colloidal suspension of the fiber‐inhibitor and elastase was employed as an assay. A dose–response relationship was observed in the kinetics of substrate hydrolysis catalyzed by three elastases: porcine pancreatic elastase, which was employed to model this approach; human leukocyte elastase; and elastase in human chronic wound fluid. Both freely dissolved and fiber‐bound inhibitors were studied. The initial rates of substrate hydrolysis were inversely linear with freely dissolved inhibitor dose. The apparent first order rate constants, kobs, for the elastase‐inhibitor complex were calculated from the kinetic profiles. The kobs for inhibitor bound enzyme varied as a function of inhibitor vs. enzyme concentration and based on the order of mixing of substrate, inhibitor and enzyme in the assay. Enzyme inhibition by the fiber‐inhibitor was measured as inhibitor concentration at 50% inhibition (I50). I50 values measured from the colloidal assay with fiber‐released inhibitor were within the same range to those for freely dissolved inhibitor. Inhibition of elastase activity in chronic wound fluid was observed with 1–5 mg of fiber‐inhibitor formulation. This approach constitutes an in vitro assessment of synthetic serine protease inhibitors on fibers and may be employed to evaluate structure vs. function of elastase inhibition in the modified fibers of wound dressing composites.
Stimulation of fibroblast growth in vitro by intermittent radiant warming
Authors: Xia Zhidao , Sato Akio , Hughes Margaret A , Cherry George W
Published: March 2003

A number of clinical studies have suggested that radiant heat improves the healing of selected acute and chronic wounds. The purpose of this study was to investigate in vitro the effect of intermittent radiant heating on the growth of human skin fibroblasts using a radiant heat‐producing dressing with a designated temperature of 38 °C. In initial experiments cells were seeded in six well‐plates, maintained in culture at 33–34 °C, and warmed daily for three cycles of 1 hour with 1.5 hour intervals. Changes in cell growth and metabolism were determined in sets of triplicate wells by cell counts and a colorimetric assay before and after one week's treatment. After eight days the number of cells in the radiant heat‐treated group was 30% higher and the metabolic activity 47%– 90% higher than in the control group. In quiescent fibroblasts which had been maintained for four weeks in low‐serum medium, the warming regime completely prevented the decrease in cell number observed in control cells. Our findings suggest that the stimulation of cell proliferation induced by intermittent heating in vitro may indicate a possible mechanism contributing to in vivo effects.
Improved airway healing using transforming growth factor beta‐3 In a rabbit model
Authors: Loewen Mark S , Walner David L , Caldarelli David D
Published: March 2003

Laryngeal wound healing is essential following laryngotracheal surgery. Patients with poor wound healing develop poor epithelial closure and increased granulation tissue which cause a stenosis of the repaired airway. Transforming growth factor‐β3 has been shown to enhance wound healing in cutaneous wounds, but has never been used in the airway. This study utilized a rabbit laryngeal wound‐healing model that has been shown to be reproducible with limited morbidity. Thirty‐four rabbits underwent a cricoid‐split operation with collagen sponge insertion. All animals were classified randomly into three groups: local administration of placebo (Group G1, n= 13), 0.18 μg transforming growth factor‐β3 (Group G2, n= 11) and of 1.0 μg transforming growth factor‐β3 (Group G3, n= 10). All animals survived the postoperative period without respiratory distress. The airway was harvested six days after surgery and assessed by light microscopy. Histologic evidence for healing was subjectively graded by two blinded, independent investigators, and the results were statistically analyzed for significance. A significant improvement in the epithelial closure (p < 0.01) and subepithelial connective tissue closure (p < 0.005) was found in the 1.0 μg transforming growth factor‐β3 group (G3) compared with the placebo group (G1). Analysis of the 0.18 μg transforming growth factor‐β3 group (G2) did not reveal any significant differences compared with the placebo group (G1). These results suggest an application for transforming growth factor‐β3 in accelerating wound healing in the larynx.
EXOGENOUS PHOSPHOLIPASE C STIMULATES EPITHELIAL CELL MIGRATION AND INTEGRIN EXPRESSION IN VITRO
Authors: Firth James D , Putnins Edward E , Larjava Hannu , Uitto Veli‐Jukka
Published: March 2003

Phospholipase C secreted by bacterial pathogens has been identified as a virulence factor in several human diseases and has been implicated in impeding wound healing. The role of phospholipase C in the intracellular signal control of epithelial growth was studied in normal human skin keratinocytes cultured in conditions simulating aspects of wound healing.Bacillus cereusphospholipase C decreased cell‐cell contact and increased cell migration resulting in disruption of the advancing epithelial sheet. Phospholipase C‐induced migration was blocked by inhibitor of the phosphoinositol signal transduction pathway neomycin sulfate and protein kinase C inhibitor RO‐31–8220. Induced migration was associated with elevated levels of matrix metalloproteinase‐9 which, when blocked by tissue inhibitor of metalloproteinase‐1, was accompanied by a loss of migration. Adhesion studies showed that phospholipase C treatment enhanced cell binding to fibronectin, vitronectin and collagen IV. Immunostained phospholipase C‐stimulated cells cultured on fibronectin showed enhanced expression and relocation of the integrin subunits αv, α5and β1. Confocal microscopy showed that phospholipase C‐induced levels of integrin subunit β1were predominantly deposited on the basal surface of the cell apparently in focal contacts and associated with actin stress fibers. These results indicate that exogenous phospholipase C signaling from a bacterial source may play an important role in perturbing normal reepithelialization via altered expression of integrins and matrix metalloproteinase‐9.
POLYVINYL PYRROLIDONE‐IODINE LIPOSOME HYDROGEL IMPROVES EPITHELIALIZATION BY COMBINING MOISTURE AND ANTISEPIS. A NEW CONCEPT IN WOUND THERAPY
Authors: Vogt Peter M. , Hauser Jorg , Roßbach Oliver , Bosse Bjoern , Fleischer Wolfgang , Steinau Han‐Ulrich , Reimer Karen
Published: March 2003

Moist treatment of wounds has been shown to improve epithelialization, however at an increased risk of bacterial infection. In this monocentric, randomized, open, phase II pilot study of polyvinyl pyrrolidone‐iodine, a well‐established topical antiseptic was tested in a new liposomal complexed form in patients receiving meshed skin grafts after burns or reconstructive procedures. Mesh skin graft sites of 36 patients were dressed either with the new polyvinyl‐pyrrolidone‐iodine liposome hydrogel formulation (Betasom hydrogel) (n= 21), or chlorhexidine‐gauze (n= 15). After the first dressing change, wounds were assessed daily and documented every other day until they were healed. Methods of analysis included clinical assessment, photoplanimetry (rate of epithelialization), impedance measurement (moisture of surface and wound healing quality), patient's assessment of pain and other sensations, and thyroid hormones (T3, T4, and TSH). The rate of epithelialization was improved with Betasom hydrogel compared to chlorhexidine‐gauze on day 11 (96.3% vs. 75.9%p= 0.056) and significantly on day 13 (100% vs. 82.3%p= 0.005), respectively. Impedance measurements showed an earlier return to normal values (day 9) in Betasom‐hydrogel–treated wounds as opposed to chlorhexidine treatment (day 11). Clinical assessment indicated significantly better antiseptic efficacy (p= 0.002) and wound healing quality (p= 0.004) of Betasom hydrogel. Graft loss occurred at a significantly lower rate in Betasom treatment (n= 1; 5%), than in chlorhexidine treatment (n= 5; 35.7%) (p= 0.001). No relevant adverse events or clinically relevant changes of thyroid hormones were observed with Betasom hydrogel. The rationale of this new polyvinyl pyrrolidone‐iodine liposomal formulation was based on the properties of liposomes that provide higher moisture to the wound surface, release PVP‐iodine at a low rate, and target the substance more exactly by interaction with the cell surface. These initial clinical results show earlier epithelialization and better healing in wounds treated with polyvinyl pyrrolidone‐iodine liposome hydrogel, which combines moisture and antisepsis, compared to wounds treated with a conventional antiseptic chlorhexidine‐gauze.
Use of a cell‐based interactive wound dressing to enhance healing of excisional wounds in nude mice
Authors: Rees Riley S. , Adamson Belinda F. , Lindblad William J.
Published: March 2003

The need to have viable, metabolically active cells to heal wounds is well recognized, because there is clear evidence that cellular dysfunction delays healing. This suggests that addition of metabolically active cells to a delayed healing tissue could enhance the healing of the tissue. Therefore, we examined the ability of an interactive wound dressing composed of human keratinocytes or fibroblasts grown on microporous bio‐reactor beads and placed into a polyethylene bag to facilitate the delayed healing of wounds in nude mice. A 1 × 1 cm wound was made on the backs of nude mice, and the dressing with or without viable cells was placed on the wound for 8 to 24 days, with dressing changes every other day. Wound area and time to heal measurements were compared after various interventions including freeze‐thawing. The data shows that the interactive wound dressing was more effective than the control dressings (p<0.05) and that keratinocytes were more effective than fibroblasts in wound healing (p<0.05). Freezing‐thawing of the interactive wound dressings destroyed the activity of the dressing. Studies examining cells using a live/dead viability assay showed that both keratinocytes and fibroblasts were alive after 2 days on the mice. Surprisingly, human fibroblasts appeared to exhibit bridging behavior that is indicative of fibroblast proliferation. We conclude that a simple interactive wound dressing using either keratinocytes or fibroblasts can enhance the healing of wounds in nude mice.
Age and growth factors in porcine full‐thickness wound healing
Authors: Yao Feng , Visovatti Scott , Johnson C. Starck , Chen Michael , Slama Jaromir , Wenger Andreas , Eriksson Elof
Published: March 2003

It has been recognized that the rate of cutaneous wound healing declines with age, yet the molecular processes that affect this decline remain poorly understood. The purpose of this study was to compare reepithelialization and contraction rates, and growth factor profiles in full‐thickness wounds in swine of various ages. Multiple full‐thickness excisional wounds were created on the dorsum of 24‐month‐old (n=2), 4‐month‐old (n=2), and 2‐month‐old (n=2) Yucatan Minipigs. The extent of reepithelialization was shown to decrease with increasing age in a manner that was statistically significant among the 2‐month‐old (79%), 4‐month‐old (48%), and 24‐month‐old pigs (22%). Enzyme‐linked immunosorbent assay results showed that endogenous vascular endothelial growth factor concentrations in the 2‐ and 4‐month‐old animals peaked on day 4, reaching levels of 482 pg/ml and 420 pg/ml, respectively. In the 24‐month‐old pigs the vascular endothelial growth factor concentration peaked later (day 6), and was present at a lower level (229 pg/ml). On day 4 the vascular endothelial growth factor levels in the older pigs reached only 120 pg/ml, representing a four‐fold decrease in concentration compared to the younger pigs. A comparison of platelet‐derived growth factor‐BB concentrations across the age groups showed similar patterns in the 2‐ and 4‐month‐old pigs (peaks of 77 and 91 pg/ml on days 2 and 3, respectively), and levels in the 24‐month‐old were below the sensitivity level (31.5 pg/ml) of the assay. Transforming growth factor‐β1 levels across the age groups did not differ in a manner that was statistically significant, and all age groups peaked on day 9. Wound contraction showed no statistical differences among the age groups from days 3 to 9. On day 11, however, wound contraction in 2‐month‐old pigs was about 10% faster than in 24‐month‐old pigs (p < 0.05). These data suggest a possible new algorithm for treating wounds in aged skin, by which exogenous growth factors can be added to the wound microenvironment in doses and at times that match the growth factor profiles observed in wounds made in younger skin.
Age‐dependency of insulin‐like growth factors, insulin‐like growth factor–binding proteins, and acid labile subunit in plasma and wounds of surgical patients
Authors: Wicke Corinna , Wagner Silvia , Trabold Odilo , Müller Jürgen , Hunt Thomas K. , Ranke Michael B. , Becker Horst‐Dieter , Elmlinger Martin W.
Published: March 2003

Wound problems are common in the elderly. We hypothesized that age‐related decrements in blood levels of components of the insulin‐like growth factor (IGF) system are reflected in the wound environment. In this prospective, observational study IGF‐I, IGF‐II, IGF‐binding protein‐2, IGF‐binding protein‐3, and acid labile subunit were measured by immunoassays in the wound fluid and plasma of young (23.5 ± 3.3 years) and elderly (78.9 ± 6.2 years) patients before and daily for 4 days after elective surgery. IGFs, IGFBP‐3, and acid labile subunit in plasma were significantly lower in the elderly group (p < 0.0001). The decrements of these proteins in plasma were reflected in corresponding decrements of 25–70% in the wound fluid of elderly patients (p < 0.0001). Additionally, bioavailability of IGF‐I was less in the aged. The IGF parameters in the wound displayed a constant ratio with those of blood, suggesting that blood contributes a major share of the IGF that enters the wound during the initial phase of healing. The current data adds to accumulating evidence that a decline in the IGF system in aged patients contributes to the healing deficits observed in the elderly. (WOUND REP REG 2002;10:360–365)
Fluid evolution during metamorphism of the Otago Schist, New Zealand: (II) Influence of detrital apatite on fluid salinity
Authors: SMITH*  , YARDLEY
Published: March 2003

Apatite occurs in the zeolite to greenschist facies metamorphic rocks of the Otago Schist, South Island, New Zealand, as both a groundmass constituent and as a hydrothermal phase hosted in metamorphic quartz veins. Groundmass apatite from low‐grade rocks, ranging from the zeolite facies to the pumpellyite–actinolite zone, has chloride contents ranging from 0–1.4 wt%, and fluoride contents ranging from 2.2–4.2 wt%, whilst groundmass apatite from the greenschist facies (chlorite to biotite zone) is virtually pure fluorapatite. Vein apatite from all grades is also fluorapatite with little or no chloride. This difference in composition is interpreted as resulting from the preservation of the primary magmatic compositions of detrital Cl‐apatite grains, out of equilibrium with the metamorphic fluid, at low grades, whilst higher‐grade groundmass apatite and neoformed apatite in quartz veins have compositions in equilibrium with an aqueous metamorphic fluid. The presence of detrital Cl‐bearing apatite during the early stages of metamorphism may constitute a significant reservoir of Cl, given the low porosities of compacted sediments undergoing prograde metamorphism. Calculations indicate that the release of Cl from detrital apatite in the Otago Schist, as a result of re‐equilibration of apatite with the pore fluid, may have had a significant effect on the salinity of the metamorphic fluid.
Reaction progress in chloritic material: an electron microbeam study of the Taveyanne greywacke, Switzerland
Authors: SCHMIDT*  , LIVI  , FREY
Published: March 2003

Chlorite and associated minerals from the volcanogenic Taveyanne metasediment of the western Helvetic nappes, Switzerland, were investigated by electron microprobe (EMP) and transmission electron microscopy (TEM) in order to determine their textural and chemical evolution during low‐temperature metamorphism. EMP analyses of chloritic material from sub‐greenschist facies outcrops show a decrease of Si and Σ(Ca, Na, K) with increasing metamorphic grade. A number of conclusions may be drawn from combined TEM images and analytical electron microscopy (AEM) data.

1 In diagenetic‐grade samples, chlorite crystals (observed maximum defect‐free distance=80 nm) always contain some 1 nm layers (with a maximum of 29% of all layers) and less frequently some 0.7 nm berthierine‐like layers. With increasing grade, the amounts of 1 and 0.7 nm layers decrease, and most chlorite from the epizone is structurally pure or contains less than 2% of 1 nm layers.

2 A positive correlation was found between the amount of 1 nm layers and the Ca+K+Na content, indicating that the 1 nm layers are saponite.

3 Observations and calculations suggest that the transformation reaction of saponite to chlorite takes place by the replacement of the interlayer cations in saponite by brucite‐like layers resulting in a local volume decrease. In contrast, the destruction of berthierine has only minor influence on the local bulk volume.

These results confirm recent studies which show that the change in composition measured by EMP of diagenetic‐grade chloritic material are mainly the result of mixtures of chlorite and saponite. The use of chlorite ‘geothermometry’ in such systems is greatly influenced by the presence of saponite and hence is not based on reaction equilibria, even though temperatures calculated in this study agree with temperatures derived from other methods. Therefore, chlorite evolution should be treated as a kinetically controlled grade indicator and developed as a qualitative scale similar to the illite crystallinity index.
Amphibolite to granulite transition in aluminous greywackes from the Sierra de Comechingones, Córdoba, Argentina
Authors: Otamendi  , Patiño Douce  , Demichelis
Published: March 2003

We discuss upper‐amphibolite to granulite facies, early Palaeozoic metamorphism and partial melting of aluminous greywackes from the Sierra de Comechingones, SE Sierras Pampeanas of Central Argentina. Consistent P–T  estimates, obtained from equilibria involving Al and Ti exchange components in biotite and from more traditional thermobarometric equilibria, suggest that peak metamorphism of the exposed section took place at an essentially constant pressure of 7–8 kbar, and at temperatures ranging from 650 to 950 °C. Mineral compositions record an initial decompression, after peak metamorphism, of c. 1.5 kbar, which was accompanied by a cooling of c. 100 °C. Upper‐amphibolite facies gneisses consist of the assemblage Qtz+Pl+Bt+Grt+Rt/Ilm. The transition to the granulite facies is marked by the simultaneous appearance of the assemblage Kfs+Sil and of migmatitic structures, suggesting that the amphibolite to granulite transition in the Sierra de Comechingones corresponds to the beginning of melting. Rocks with structural and/or chemical manifestations of partial melting range from metatexites, to diatexites, to melt‐depleted granulites, consisting of the assemblage Grt+Crd+Pl+Qtz+Ilm±Ath. The melting stage overlapped at least partially with decompression, as suggested by the occurrence of cordierite, in both the migmatites and the residual granulites, of two distinct textural types: idiomorphic porphyroblasts (probably representing peritectic cordierite) and garnet‐rimming coronas. Metapelitic rocks are unknown in the Sierra de Comechingones. Therefore, it appears most likely that the Al‐rich residual assemblages found in the migmatites and residual granulites were formed by partial melting of muscovite‐ and sillimanite‐undersaturated metagreywackes. We propose a mechanism for this that relies on the sub‐solidus stabilization of garnet and the ensuing changes in the octahedral Al content of biotite with pressure and temperature.
Garnet zoning and the identification of equilibrium mineral compositions in high‐pressure–temperature granulites from the Moldanubian Zone, Austria
Authors: Cooke  , O’Brien  , Carswell
Published: March 2003

A detailed investigation of the compositional variation in garnet has been undertaken in a garnet–pyroxene‐bearing granulite from the high‐grade Gföhl Unit, Moldanubian Zone, Lower Austria. Textural observations, together with the interpretation of the preserved garnet chemistry, enables the recognition of both prograde core and peak metamorphic garnet mantle growth stages, an extremely rare feature in high‐P–T  granulite facies rocks. Initial thermobarometric calculations undertaken across whole garnet zoning profiles show how correct interpretation of a zoning profile is essential if the maximum peak metamorphic P–T  conditions are to be recovered. The effect of retrograde decompression‐ and cooling‐driven reactions on inclusion and host garnet compositions has also been assessed. The results indicate that caution should be exercised when utilizing inclusion and adjacent garnet compositions for the thermobarometric evaluation of peak metamorphic equilibration conditions. Peak P–T conditions were determined by the TWEEQU thermobarometric method, utilizing the core compositions of matrix phases combined with the interpreted high‐P–T  garnet mantle composition, to give 15.6 kbar and 1090 °C, consistent with previously determined results for Moldanubian granulites. Similar high‐P–T estimates are also provided by a re‐evaluation of previously published results for a granulite sample from the same lithological unit, using a modified interpretation of garnet and plagioclase compositional data. The new estimates presented confirm the previously disputed idea that the Gföhl Unit underwent a high‐pressure granulite facies stage and is therefore distinctly different from the underlying tectonostratigraphic units. It is emphasized that any interpretation of the peak metamorphic conditions in high‐grade rocks must be based on detailed petrographic observations combined with a thorough understanding of the co‐existing equilibrium mineral compositions.
Origin, HP/LT metamorphism and cooling of ophiolitic mélanges in southern Evia (NW Cyclades), Greece
Authors: Katzir Y. , Avigad * D. , Matthews A. , Garfunkel Z. , Evans B. W.
Published: March 2003

Basic and ultrabasic blocks within ophiolitic mélanges of the Cycladic Blueschist Unit in southern Evia provide a detailed insight into its ocean floor igneous and hydrothermal evolution, as well as the regional poly‐metamorphism occurring during Alpine orogenesis. The upper structural levels (Mt. Ochi exposures) are dominated by metamorphosed wehrlites, gabbros and highly light rare earth element (LREE)‐enriched pillow basalts, whereas the underlying Tsaki mélange consists of basic protoliths with much less fractionated REE patterns as well as mantle harzburgites. Most of the metabasites show Nb anomalies, indicative of derivation from a subduction‐affected mantle. The igneous bodies were juxtaposed and incorporated into the enclosing sedimentary sequences prior to high‐pressure/low‐temperature (HP/LT) metamorphism (M1). Glaucophane, epidote, sodic clinopyroxene and high‐Si phengite constitute the Eocene M1 assemblage, which is estimated to have formed at >11 kbar and 400–450 °C. High δ18O values of M1 minerals in Ochi metagabbros indicate that the formation of the high‐pressure assemblage was controlled by infiltration of fluids from the dehydrating host sediments. Cooling during decompression is indicated by an overprinting (M2, Early Miocene) pumpellyite–actinolite facies assemblage in metabasic rocks, calculated to have developed at P<8 kbar and T <350 °C. Possible mechanisms for such cooling include: exhumation from shallower burial levels relative to the eclogites of the NW Cyclades, accretion of colder rocks from below and extensional unroofing by low‐angle normal faults and detachments. The occurrence of sodic augite in the M2 assemblage of Tsaki metagabbros indicates that rocks at the base of the Blueschist Unit cooled faster or longer than their higher level Ochi counterparts. This suggests that differential cooling of the blueschists was enhanced by the underthrusting of colder rock units.
ACID‐BASE IN RENAL FAILURE: Twice‐Told Tales of Metabolic Acidosis, Glucocorticoids, and Protein Wasting: What Do Results from Rats Tell Us About Patients with Kidney Disease?
Authors: Bailey James L. , Mitch William E.
Published: March 2003

Much has been learned from animal studies in chronic renal failure that is germane to clinical studies because animal models parallel human responses. Such studies have affirmed that correction of metabolic acidosis has a favorable effect on protein metabolism, nitrogen balance and growth. In the presence of metabolic acidosis, catabolism is increased in uremia. Glucocorticoids are involved in accelerating protein degradation in muscle, which results in loss of lean body mass, while a low insulin level appears to play a permissive role in accelerating increased catabolism. Cellular mechanisms mediating these changes include upregulation of the ubiquitin‐proteasome pathway and branched‐chain ketoacid dehydrogenase enzyme activity in muscle. Many of these findings from rat studies have been confirmed in human studies and have important clinical implications because correction of metabolic acidosis improves nutritional status and blunts the associated increase in protein catabolism.
The Pathogenesis of β2‐Microglobulin–Induced Bone Lesions in Dialysis‐Related Amyloidosis
Authors: Tran Martin , Rutecki Gregory W. , Sprague Stuart M.
Published: March 2003

Dialysis‐related amyloidosis (DRA), also referred to as β2‐microglobulin amyloidosis (Aβ2M), is an important cause of morbidity in patients with chronic renal failure and in those who are on dialysis. Although DRA deposits from affected joints have been characterized as a unique amyloid fibril protein, β2M, less is known about the pathologic role of β2M as a mediator of bone and joint disease. Potential mechanisms for β2M pathologic interaction in bone include bone growth factors, cytokines, and advanced glycation end products (AGEs). It appears that DRA is the result of a complex interaction between bone resorption and surrounding tissue destruction culminating in β2M deposition and amyloid formation. More work is required to elucidate the relationship between β2M accumulation and progressive tissue destruction.
Pathogenesis of β2‐Microglobulin Amyloidosis: Role of Monocytes/Macrophages
Authors: Hou Fan Fan , Reddan Donal N. , Seng Wong Kok , Owen William F.
Published: March 2003

β2‐microglobulin (β2M) amyloidosis (Aβ2M) is a serious, often incapacitating complication for patients undergoing long‐term hemodialysis. Amyloid deposits composed of β2M fibrils as the major constituent protein are mainly localized in joints and periarticular bone and lead to chronic arthralgias, carpal tunnel syndrome, and eventually destructive arthropathy. Although recent histologic studies have shown the accumulation of monocytes/macrophages around amyloid deposits, the factor(s) causing their infiltration and pathologic involvement have yet to be fully elucidated. Immunohistochemical staining reveals that macrophages in tenosynovial tissues express CD13, CD14, CD33, HLA‐DR, and CD68 antigens on their surfaces and express interleukin (IL)‐1β, tumor necrosis factor (TNF)‐α, and IL‐6. Many of these cells also express LFA‐1 (CD11a/CD18), Mac‐1 (CD11b/CD18), and VLA‐4 (CD49d/CD29) on their surfaces. AGE‐modified β2M enhances chemotaxis of monocytes and stimulates macrophages to release bone‐resorbing cytokines, such as IL‐1β, TNF‐α and IL‐6. Via a RAGE‐mediated pathway, AGE‐modified, but not unmodified β2M, significantly delays constitutive apoptosis of human peripheral blood monocytes. Monocytes survival in an advanced glycation end product (AGE) β2M‐containing microenvironment is associated with their phenotypic alteration into macrophage‐like cells that generate more reactive oxygen species and elaborate greater quantities of IL‐1β and TNF‐α. Thus through regulation of their survival and differentiation, AGE β2M in amyloid deposits may be able to influence the presence and quantity of infiltrated monocytes, and hence their biologic effects.
Alternative Medicine and Nephrology Series Editor: Naomi V. Dahl: Herbs and Supplements in Dialysis Patients: Panacea or Poison?
Authors: Dahl Naomi V.
Published: March 2003

The safety of herbal remedies and supplement use is of particular concern in patients with renal disease, and reliable information is not always easy to find. Predialysis patients may be drawn to complementary and alternative medicine (CAM) because they believe it can help prevent the progression of their renal disease. The purpose of this series of articles on alternative medicine for nephrologists is to address concerns and issues specific to CAM use in dialysis patients and to provide a guide to reliable sources of information. This introductory article emphasizes safety issues with a focus primarily on herbal medicine. Lack of regulation means that patients may not actually be taking what they think they are. Independent laboratory analyses have shown a lack of stated label ingredients and many instances of supplements and traditional remedies being contaminated with pesticides, poisonous plants, heavy metals, or conventional drugs. While certain supplements are always unsafe (carcinogenic, hepatotoxic, glandular extracts), others are specifically contraindicated in renal disease. Supplement use may be especially hazardous in renal disease because of unpredictable pharmacokinetics, drug interactions, negative effects on kidney function, nephrotoxicity, hemodynamic alterations, unpredictable effects on blood pressure or blood glucose, or potentiation of electrolyte abnormalities. There are no data on potential dialyzability of either active compounds, or their potentially active or toxic metabolites. Many supplements contain metal ions and other minerals. Transplant recipients are also at risk from potential unpredictable effects on immune function. Recommendations and information resources are listed.
Chronic Dialysis and Dialysis Doctors in the United States: A Nephrologist‐Historian's Perspective
Authors: Peitzman Steven J.
Published: March 2003

In an earlier article in Seminars in Dialysis (9:276–281, 1996), the author described the invention of clinical hemodialysis for acute renal failure and its initially equivocal reception by the emerging specialty of nephrology in the United States. A similar story of blunted enthusiasm played out following the invention of the Quinton–Scribner shunt (whose idea “came in the night”), which allowed maintenance treatment for chronic renal failure. Few centers at first could match Belding Scribner's early successes, and some physiology‐oriented university nephrologists envisioned how routine dialysis might swamp other activities. Nonetheless, increasingly complex and successful inventions appeared and prevailed: the chronic dialysis unit, the national dialysis chain. A unique federal entitlement program fostered the spread of maintenance dialysis, but so did the emergence of disposable off‐the‐shelf supplies and many new nephrologists trained in academia but seeking positions in practice. Indeed, the spread of end‐stage renal disease (ESRD) care transformed American nephrology. The essay concludes by considering what nephrologists of the ESRD era share with their patients.
L‐Carnitine in Dialysis Patients
Authors: Ahmad Suhail
Published: March 2003

Hemodialysis (HD) patients often have low serum concentrations of free L‐carnitine and decreased skeletal muscle stores. As L‐carnitine is an essential cofactor in fatty acid and energy metabolism, it is possible that abnormal carnitine metabolism in dialysis patients may be associated with clinical problems such as skeletal myopathies, intradialytic symptoms, reduced cardiac function, and anemia. Studies have shown that L‐carnitine supplementation in HD patients improves several complications seen in dialysis patients, including cardiac complications (arrhythmias, reduced output, low cardiothoracic ratio), limitation of exercise capacity, increased intradialytic hypotension, and muscle symptoms. The most promising results have been noted in the treatment of erythropoietin‐resistant anemia. Routine administration of L‐carnitine to all dialysis patients is not recommended at this time; however, a therapeutic trial of L‐carnitine can be useful in symptomatic patients with certain clinical features unresponsive to the usual measures. These include intradialytic muscle cramps and hypotension, asthenia, cardiomyopathy, lowered ejection fraction, muscle weakness or myopathy, reduced oxygen consumption, and anemia requiring large doses of EPO.