IntroductionGlycation, oxidation, and browning of proteins have all been implicated in the development of diabetic complications. We measured the initial Amadori adduct, fructoselysine (FL); two Maillard products, NE-(carboxymethyl) lysine (CML) and pentosidine; and fluorescence (excitation = 328 nm, emission = 378 nm) in skin collagen from 39 type 1 diabetic patients (aged 41.5±15.3 117-731 yr; duration of diabetes 17.9±11.510-461 yr, Imean±SD, rangel). The measurements were related to the presence of background (n = 9) or proliferative (n = 16) retinopathy; early nephropathy (24-h albumin excretion rate IAER241 > 20 Ag/min; n = 9); and limited joint mobility (LJM; n = 20). FL, CML, pentosidine, and fluorescence increased progressively across diabetic retinopathy (P < 0.05, P < 0.001, P < 0.05, P < 0.01, respectively). FL, CML, pentosidine, and fluorescence were also elevated in patients with early nephropathy (P < 0.05, P < 0.001, P < 0.01, P < 0.01, respectively). There was no association with LJM. Controlling for age, sex, and duration of diabetes using logistic regression, FL and CML were independently associated with retinopathy (FL odds ratio (OR) = 1.06, 95% confidence interval (CI) = 1. (19,20). These changes are accelerated in diabetic patients (21), whose collagen contains significantly increased quantities of the initial product of glycation, fructoselysine (FL)' (22). However, there is little evidence to date that FL is directly implicated in the altered properties ofcollagen. The FL content of skin collagen increases only slightly with age in nondiabetic individuals (22,23), and although elevated in diabetes, it is unrelated to age or duration of diabetes (22). In existing studies, collagen FL has not been associated with the presence or severity of diabetic complications (24, 25), and even in patients with long-standing diabetes, its concentration in collagen falls promptly with improved glycemic control (26). In vitro, short-term glycation ofcollagen does not increase its resistance to enzymatic digestion (27).FL may, however, be indirectly linked with the altered properties of collagen in both aging and diabetes. In long-lived proteins, FL undergoes further dehydration, rearrangement, and cleavage reactions, which comprise the later stages ofthe Maillard reaction (28-30). Many of these reactions involve oxidative processes, and their products, whose formation (in contrast to that of FL) is irreversible (26), have recently been termed "glycoxidation products" (6). Oxidation may therefore be regarded as a "fixative" ofglycative damage to proteins. The intimate interrelationship between glycation and oxida-1. Abbreviations used in this paper: AER24, 24-h albumin excretion rate; CI, confidence interval; CML, N-(carboxymethyl)lysine; FL, fructoselysine, Hb, hemoglobin; LJM, limitation of joint mobility; MHbA,, mean HbA,, OR, odd ratio. tion is further emphasized by the observation that increased glycation may, in itself, promote the formation of free radicals and therefore enhance oxidative...

To investigate the contribution of glycation and oxidation reactions to the modification of insoluble collagen in aging and diabetes, Maillard reaction products were measured in skin collagen from 39 type 1 diabetic patients and 52 nondiabetic control subjects. Compounds studied included fructoselysine (FL), the initial glycation product, and the glycoxidation products, N'-(carboxymethyl)lysine (CML) and pentosidine, formed during later Maillard reactions. Collagen-linked fluorescence was also studied. In nondiabetic subjects, glycation of collagen (FL content) increased only 33% between 20 and 85 yr of age. In contrast, CML, pentosidine and fluorescence increased fivefold, correlating strongly with age. In diabetic patients, collagen FL was increased threefold compared with nondiabetic subjects, correlating strongly with glycated hemoglobin but not with age. Collagen CML, pentosidine and fluorescence were increased up to twofold in diabetic compared with control patients: this could be explained by the increase in glycation alone, without invoking increased oxidative stress. There were strong correlations among CML, pentosidine and fluorescence in both groups, providing evidence for age-dependent chemical modification ofcollagen via the Maillard reaction, and acceleration of this process in diabetes. These results support the description of diabetes as a disease characterized by accelerated chemical aging of long-lived tissue proteins. (J. Clin. Invest.

In a historical cohort study of all singleton live births in Northern Ireland from 1971 -86 (n=434 933) associations between early life factors and childhood acute lymphoblastic leukaemia were investigated. Multivariable analyses showed a positive association between high paternal age (535 years) and acute lymphoblastic leukaemia (relative risk=1.49; 95% confidence interval (CI)=0.96 -2.31) but no association with maternal age. High birth weight (53500 g) was positively associated with acute lymphoblastic leukaemia (relative risk=1.66; 95% CI=1.18 -2.33). Children of mothers with a previous miscarriage or increased gestation (540 weeks) had reduced risks of ALL (respective relative risks=0.49; 95% CI=0.29 -0.80, and 0.67; 95% CI=0.48 -0.94). Children born into more crowded households (51 person per room) had substantially lower risks than children born into less crowded homes with also some evidence of a lower risk for children born into homes with three adults (relative risks=0.56; 95% CI=0.35 -0.91 and 0.58; 95% CI=0.21 -1.61 respectively). These findings indicate that several early life factors, including living conditions in childhood and maternal miscarriage history, influence risk of acute lymphoblastic leukaemia in childhood.

Glycation, oxidation, and nonenzymatic browning of protein have all been implicated in the development of diabetic complications. The initial product of glycation of protein, fructoselysine (FL), undergoes further reactions, yielding a complex mixture of browning products, including the fluorescent lysine-arginine cross-link, pentosidine. Alternatively, FL may be cleaved oxidatively to form Nf-(carboxymethyl)lysine (CML), while glycated hydroxylysine, an amino-acid unique to collagen, may yield N4-(carboxymethyl)hydroxylysine (CMhL). We have measured FL, pentosidine, fluorescence (excitation = 328 nm, emission = 378 nm), CML, and CMhL in insoluble skin collagen from 14 insulin-dependent diabetic patients before and after a 4-mo period of intensive therapy to improve glycemic control. Mean home blood glucose fell from 8.7±2.5 (mean±1 SD) to 6.8±1.4 mM (P < 0.005), and mean glycated hemoglobin (HbA,) from 11.6±2.3% to 83±1.1% (P < 0.001). These changes were accompanied by a significant decrease in glycation of skin collagen, from 13.2±4.3 to 10.6±2.3 mmol FL/mol lysine (P < 0.002). However, levels of browning and oxidation products (pentosidine, CML, and CMhL) and fluorescence were unchanged. These results show that the glycation of longlived proteins can be decreased by improved glycemic control, but suggest that once cumulative damage to collagen by browning and oxidation reactions has occurred, it may not be readily reversed. Thus, in diabetic patients, institution and maintenance of good glycemic control at any time could potentially limit the extent of subsequent long-term damage to proteins by glycation and oxidation reactions. (J. Clin. Invest. 1991.

BACKGROUND:Shrinkage of the donor pool coupled with an increasing demand for blood presents a major challenge to maintaining an adequate blood supply. Consequently it has become even more important to reduce inappropriate blood use, including decisions about when and how much blood to prescribe. This study aimed to ascertain the levels of inappropriate practice and factors associated with it. STUDY DESIGN AND METHODS:The medical records of a randomly selected sample of hospital patients in Northern Ireland who received a red blood cell transfusion during 2005 (n = 1474) were reviewed, and inappropriate transfusion and overtransfusion criteria were applied. Logistic regression models were used to identify factors associated with inappropriate practice and overtransfusion. RESULTS: In this study 23% of transfusions were considered inappropriate, occurring most commonly where the lowest hemoglobin (Hb) threshold for transfusion applied. Younger patients, those undergoing surgery, and those with lower comorbidity and higher Hb values were most likely to have an inappropriate transfusion. Among patients appropriately transfused, 19% were overtransfused. Females and those of lower weight (<65 kg) were most likely to be overtransfused. CONCLUSION: While the choice of criteria used to judge decisions will influence the absolute level of inappropriate or overtransfusion reported, our findings suggest that a significant minority of clinicians are either unaware of or are reluctant to accept lower transfusion thresholds. To improve further improve transfusion practice we suggest that barriers to the implementation of recommended transfusion thresholds should be examined and guidance on an appropriate posttransfusion Hb level developed.