Accumulation of Maillard reaction products in skin collagen in diabetes and aging.
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Aging↗
Biomedical subjects
J A Dunn
Publications and source records attributed to J A Dunn.
Aflatoxin-transformed C3H/10T1/2 cells overexpress protein kinase C and have an altered response to phorbol ester treatments.
The aflatoxin B1-transformed C3H/10T1/2 (10T1/2) cell line 7SA has disordered growth in culture and is tumorigenic in syngeneic mice. Chronic exposure (14 days) of 10T1/2 and 7SA cells to phorbol 12,13-dibutyrate (PDBu) increased the saturation density of 10T1/2 cells but dramatically slowed the entry of 7SA cells into the log phase of growth without affecting their final saturation density. Similar PDBu treatment of low-density cultures dramatically decreased the size of 7SA colonies. Both cell lines bound [3H]PDBu in a specific and saturable manner. Analysis of this binding yielded linear Scatchard plots for both cell lines with distinctly different Kd values (10.7 nM for 10T1/2 versus 54.5 nM for 7SA). The total amount of [3H]PDBu bound was 2-fold greater in the 7SA cells versus the 10T1/2 cell line. Both cell lines released arachidonic acid following a 2-h exposure to PDBu; however, the magnitude of the response of the 7SA cells was only one-half that of the 10T1/2 cells. Western blot analysis of protein kinase C (PKC) using specific anti-PKC antibodies revealed a greater total amount of PKC alpha in the 7SA cells relative to an equal number of 10T1/2 cells. No immunoreactive PKC alpha was found in either cell line 16 h after exposure to 600 nM PDBu; however, PKC alpha returned to control levels in both cell lines 24 h after removal of the phorbol ester. These results suggest that an overexpression of PKC alpha may play a role in the altered biological properties of aflatoxin-transformed 10T1/2 cells.
Aflatoxin B1↗
The selection of cases for randomised trials: a registry survey of concurrent trial and non-trial patients. The British Stomach Cancer Group.
A randomised trial of adjuvant chemotherapy vs placebo in operable stomach cancer recruited 249 patients from the West Midlands Region between 1976-1980. A Cancer Registry survey identified a further 1261 suitable concurrent cases. Trial patients were compared with the 960 non-trial cases from participating Districts. Only 493 (51%) non-trial cases passed all of the prospective trial selection criteria for entry. Stage and fitness caused the majority of exclusions and were also highly prognostic. A univariate analysis comparing eligible patients with the trial showed the two groups to be balanced for the significant independent prognostic factors of the trial. However, differences in patient age and the surgery performed indicate that recruitment may have been influenced by unknown selection factors. This survey highlights the difficulty of retrospective selection and confirms the need for randomised controls. Data available from specialist Registries may be used to help develop new protocols and to verify and extend trial results.
Adolescent↗
Phase III randomised study of zoladex versus stilboestrol in the treatment of advanced prostate cancer.
An open randomised Phase III trial was conducted of the depot GnRH analogue goserelin (Zoladex) versus stilboestrol (3 mg/day) in patients with advanced or metastatic prostate cancer. The study included 250 patients and the median follow-up was 43 months. In the Zoladex arm the time to first response was achieved earlier and more patients reported an improvement in symptoms. There was no statistically significant difference between the Zoladex and the stilboestrol arms with regard to survival and time to treatment failure. A major reason for treatment failure was the preponderance of adverse events in patients receiving stilboestrol. It is suggested that stilboestrol should no longer be used for prostate cancer when equally effective alternative treatments are available.
Aged↗
Leiomyosarcomas have a poorer prognosis than mixed mesodermal tumours when adjusting for known prognostic factors: the result of a retrospective study of 423 cases of uterine sarcoma.
OBJECTIVE: To determine the survival data for the various tumour types of uterine sarcoma and determine the influence of various prognostic factors on survival. DESIGN: Retrospective analysis of all uterine sarcoma cases registered in the 15 year period 1967-1981. SETTING: West Midlands Regional Cancer Registry, serving a catchment area of 2.6 million women. SUBJECTS: 423 women registered as having a uterine sarcoma; 367 of these were associated with the two main histological types, leiomyosarcomas (LMS) and mixed mesodermal tumours (MMT). MAIN OUTCOME MEASURES: Duration of survival was taken as the primary endpoint. RESULTS: The overall 5-year survival for uterine sarcomas in this series was 31%, with the major prognostic indicator being tumour stage. Survival for mixed mesodermal tumours is similar to other sarcomas despite a tendency towards less differentiation, wider dissemination and a greater age of the patient at diagnosis. Multivariate analysis shows that for cases with similar stage, age and grade, mixed mesodermal tumours have a better prognosis than leiomyosarcomas. CONCLUSIONS: These results demonstrate the danger of considering each variable in isolation when the relation between variables can lead to spurious significance or lack of significance because of the imbalances in the numbers between groups of prognostic importance. This study underlines the need for an adequate inspection of the intra-abdominal contents at the time of hysterectomy for uterine fibroids.
Adult↗
Is stage I epithelial ovarian cancer overtreated both surgically and systemically? Results of a five-year cancer registry review.
OBJECTIVE: To review the incidence of Stage I epithelial ovarian carcinoma in the West Midlands region and to identify prognostic factors that have a significant effect on survival. DESIGN: A retrospective review of all Stage I ovarian cancer patients registered from 1.1.80 to 31.12.84. SETTING: West Midlands Regional Cancer Registry. POPULATION: 457 patients with Stage I ovarian cancer--373 with epithelial ovarian carcinoma. MAIN OUTCOME MEASURES: Survival at censor date of 30.6.89. RESULTS: 28% developed recurrent disease, and the overall 5-year survival of the group was 70%. Univariate analysis of all possible prognostic factors showed that stage, adjuvant chemotherapy, histological grade and type, surgical rupture of the tumour, intact capsule histologically, clinical finding of ascites and the performance of peritoneal washings were significantly associated with survival. Adequate surgical staging as defined by FIGO was not significantly associated with survival. A multivariate analysis based on the Cox proportional hazard model identified histological grade, adjuvant chemotherapy, patient age and peritoneal washings as having independent prognostic effects. Surprisingly adjuvant chemotherapy and peritoneal washings had negative effects on survival. CONCLUSIONS: Although a retrospective review has limitations, it would appear that adequate surgical staging and adjuvant chemotherapy confer no benefit in terms of survival in Stage I disease.
Adolescent↗
Urologists' attitudes to the management of bladder cancer.
All consultant urologists in Great Britain and Ireland were sent 2 questionnaires relating to their management policies in bladder cancer; 82% and 78% respectively of questionnaires were completed and returned. The answers demonstrated a wide variation among urologists about the management of common clinical problems.
Attitude of Health Personnel↗
Age-dependent accumulation of N epsilon-(carboxymethyl)lysine and N epsilon-(carboxymethyl)hydroxylysine in human skin collagen.
N epsilon-(Carboxymethyl)lysine (CML) is formed on oxidative cleavage of carbohydrate adducts to lysine residues in glycated proteins in vitro [Ahmed et al. (1988) J. Biol. Chem. 263, 8816-8821; Dunn et al. (1990) Biochemistry 29, 10964-10970]. We have shown that, in human lens proteins in vivo, the concentration of fructose-lysine (FL), the Amadori adduct of glucose to lysine, is constant with age, while the concentration of the oxidation product, CML, increases significantly with age [Dunn et al. (1989) Biochemistry 28, 9464-9468]. In this work we extend our studies to the analysis of human skin collagen. The extent of glycation of insoluble skin collagen was greater than that of lens proteins (4-6 mmol of FL/mol of lysine in collagen versus 1-2 mmol of FL/mol of lysine in lens proteins), consistent with the lower concentration of glucose in lens, compared to plasma. In contrast to lens, there was a slight but significant age-dependent increase in glycation of skin collagen, 33% between ages 20 and 80. As in lens protein, CML, present at only trace levels in neonatal collagen, increased significantly with age, although the amount of CML in collagen at 80 years of age, approximately 1.5 mmol of CML/mol of lysine, was less than that found in lens protein, approximately 7 mmol of CML/mol of lysine. The concentration of N epsilon-(carboxymethyl)hydroxylysine (CMhL), the product of oxidation of glycated hydroxylysine, also increased with age in collagen, in parallel with the increase in CML, from trace levels at infancy to approximately 5 mmol of CMhL/mol of hydroxylysine at age 80.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Follow up after transurethral resection of prostate: who needs it?
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Aged↗
Retrospective analysis of 318 cases of uterine sarcoma.
A study of data from 318 cases of uterine sarcoma presenting during a 10-year period (1967-1976) is reported. All but 6 of the patients had at least a 5-year follow-up (98% 5-year follow-up). Overall 5-year survival was 31%, with the major prognostic indicator being tumour stage. Despite the tendency for mixed mesodermal tumours to present in older women with more advanced disease, survival was not statistically different to those patients with leiomyosarcomas. Thus, the propensity for tumour dissemination in leiomyosarcomas should not be underestimated. Leiomyosarcomas are less likely to present with abnormal symptoms than are other sarcomas, and their occurrence as an incidental finding on histological examination underlines the need for an adequate inspection of the intra-abdominal contents at hysterectomy. The tendency to treat all sarcomas as if they were endometrial tumours may be fallacious, and an alternative classification (such as the TNM system) may be required. Recurrence of tumour tended to be at distant sites (distant:pelvic recurrence rate 3:1). Adjuvant radiotherapy is unlikely to alter distant disease foci, and thus the development of combination chemotherapeutic regimens using agents which have shown to result in tumour response seem warranted. Such trials will need to be organised on a multicentre basis to attain statistically evaluable numbers of patients.
Adult↗
Synthesis of potential dual-acting radiation sensitizer antineoplastic agents: 2,2-dimethylphosphoraziridines containing 2-nitroimidazoles or other electron-affinic moieties.
In view of the in vivo demonstrated radiation-potentiating activities of several previously studied 2,2-dimethylphosphoraziridines, six new compounds incorporating the bis(2,2-dimethyl-1-aziridinyl)phosphinyl moiety, together with an electron-affinic group such as 2-nitroimidazole or nitrobenzyl, have been synthesized and tested (1) in vitro for ability to increase the effect of X-irradiation under hypoxic conditions on V-79 Chinese hamster lung fibroblast cells, (2) in vivo for antitumor activity in the absence of radiation against P388 leukemia in mice, and (3) in a preliminary experiment with compound 10 only, in combination with whole-body gamma-radiation, using the P388 leukemia mouse model for in vivo radiation-potentiating activity. The chemical-alkylating activities and hydrolytic behavior of these compounds, as well as their antitumor activities without radiation, were found to be comparable to those of other 2,2-dimethylphosphoraziridines, while their in vitro radiosensitizing activities were at low concentrations generally comparable to that of misonidazole, with compound 8 showing superior activity. At higher concentrations, only compound 10 was sufficiently soluble and nontoxic to the cells for evaluation in this assay. Thus, the bis(2,2-dimethyl-1-aziridinyl) phosphinyl moiety does not seem to have contributed to the hypoxic radiosensitizing activities (only to the cytotoxicities) of the electron-affinic moieties in this in vitro assay. In comparison, the prototype 2,2-dimethylphosphoraziridine, ethyl [bis(2,2-dimethyl-1-aziridinyl) phosphinyl]carbamate (AB-132), showed at nontoxic doses no radiosensitizing activity in this assay, and at cytotoxic doses increased the cell-killing effect of each given dose of X-radiation additively under both hypoxic and oxic conditions. Conversely, only the 2,2-dimethylphosphoraziridine moiety appeared to participate in the moderate "therapeutic radiation-potentiating" activity indicated by compound 10 in the in vivo experiment using the P388 leukemia model (on day 1), as the misonidazole standard was inactive in this nonhypoxic system. Clearly, the mechanism of the in vivo observed radiation-potentiating effect of AB-132 and other 2,2-dimethylphosphoraziridines is different from that of the hypoxic radiosensitizers, but the possible synergism between the two biologically active moieties of the new compounds could not be demonstrated with the experimental models so far employed.
Animals↗
Decrease in skin collagen glycation with improved glycemic control in patients with insulin-dependent diabetes mellitus.
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 N(epsilon)-(carboxymethyl)lysine (CML), while glycated hydroxylysine, an amino-acid unique to collagen, may yield N(epsilon)-(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 less than 0.005), and mean glycated hemoglobin (HbA1) from 11.6 +/- 2.3% to 8.3 +/- 1.1% (P less than 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 less than 0.002). However, levels of browning and oxidation products (pentosidine, CML, and CMhL) and fluorescence were unchanged. These results show that the glycation of long-lived 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.
Arginine↗
Effect of diabetes and aging on carboxymethyllysine levels in human urine.
Carboxymethyllysine (CML) has been identified as a modified amino acid that accumulates with age in human lens proteins and collagen. CML may be formed by oxidation of fructoselysine (FL), the Amadori adduct formed on nonenzymatic glycosylation of lysine residues in protein, or by reaction of ascorbate with protein under autoxidizing conditions. We proposed that measurements of tissue and urinary CML may be useful as indices of oxidative stress or damage to proteins in vivo. To determine the extent to which oxidation of nonenzymatically glycosylated proteins contributes to urinary CML, we measured the urinary concentrations of FL and CML in diabetic (n = 26) and control (n = 28) patients. The urinary concentration of FL correlated strongly with HbA1 measurements and was significantly higher in diabetic compared with control samples (9.2 +/- 6.5 and 4.0 +/- 2.8 micrograms/mg creatinine, respectively; P less than 0.0001). There was also a strong correlation between the concentrations of CML and FL in both diabetic and control urine (r = 0.67, P less than 0.0001) but only a weakly significant increase in the CML concentration in diabetic compared with control urine (1.2 +/- 0.5 and 1.0 +/- 0.3 micrograms/mg creatinine, respectively; P = 0.05). The molar ratio of CML to FL was significantly lower in diabetic compared with control patients (0.25 +/- 0.12 and 0.43 +/- 0.16, respectively; P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Role of glycation in modification of lens crystallins in diabetic and nondiabetic senile cataracts.
To assess the significance of glycation, nonenzymatic browning, and oxidation of lens crystallins in cataract formation in elderly diabetic patients, we measured three distinct products of glycation, browning, and oxidation reactions in cataractous lens crystallins from 29 diabetic patients (mean +/- SD age 72.8 +/- 8.8 yr) and 24 nondiabetic patients (age 73.5 +/- 8.3 yr). Compounds measured included 1) fructoselysine (FL), the first stable product of glycation; 2) pentosidine, a fluorescent, carbohydrate-derived protein cross-link between lysine and arginine residues formed during nonenzymatic browning; and 3) N epsilon-(carboxymethyl)lysine (CML), a product of autoxidation of sugar adducts to protein. In diabetic compared with nondiabetic patients, there were significant increases (P less than 0.001) in HbA1 (10.2 +/- 3.1 vs. 7.1 +/- 0.7%), FL (7.6 +/- 5.4 vs. 1.7 +/- 1.2 mmol/mol lysine), and pentosidine (6.3 +/- 2.8 vs. 3.8 +/- 1.9 mumol/mol lysine). The disproportionate elevation of FL compared with HbA1 suggests a breakdown in the lens barrier to glucose in diabetes, whereas the increase in pentosidine is indicative of accelerated nonenzymatic browning of diabetic lens crystallins. CML levels were similar in the two groups (7.1 +/- 2.4 vs. 6.8 +/- 3.0 mmol/mol lysine), providing no evidence for increased oxidative stress in the diabetic cataract. Thus, although the modification of lens crystallins by autoxidation reactions was not increased in diabetes, the increase in glycation and nonenzymatic browning suggests that these processes may acclerate the development of cataracts in diabetic patients.
Aged↗
Qualitative and quantitative analysis of peritoneal fluids from women with gynecologic diseases. Comparison of cytology and flow cytometry for the detection of malignancy in lavage and ascitic fluids.
A prospective study was undertaken to compare flow cytometric (FCM) analysis to conventional cytologic evaluation for the detection of malignant cells in peritoneal fluids (peritoneal lavages and ascitic fluids) from women with gynecologic diseases. The 94 peritoneal fluids analyzed came from 63 cancer patients (with epithelial ovarian carcinomas) and 31 control patients (with benign gynecologic diseases). The FCM DNA histograms were generated using propidium iodide as a DNA fluorochrome. Samples for cytologic analysis were stained with the standard May-Grünwald-Giemsa or Papanicolaou stains. Of the 94 samples, 90 were evaluable cytologically while 70 were suitable for FCM analysis. The sensitivities were 55% for FCM DNA analysis and 80% for cytologic analysis. FCM DNA analysis had a 30% false-positive rate; cytologic analysis produced no false-positive results. These results indicate that there is no advantage in employing FCM analysis instead of conventional cytologic evaluation for the detection of malignant cells in peritoneal fluids from gynecologic cases.
Adolescent↗
Reaction of ascorbate with lysine and protein under autoxidizing conditions: formation of N epsilon-(carboxymethyl)lysine by reaction between lysine and products of autoxidation of ascorbate.
N epsilon-(Carboxymethyl)lysine (CML) has been identified as a product of oxidation of glucose adducts to protein in vitro and has been detected in human tissue proteins and urine [Ahmed, M. U., Thorpe, S. R., & Baynes, J. W. (1986) J. Biol. Chem. 261, 4889-4894; Dunn, J. A., Patrick, J. S., Thorpe, S. R., & Baynes, J. W. (1989) Biochemistry 28, 9464-9468]. In the present study we show that CML is also formed in reactions between ascorbate and lysine residues in model compounds and protein in vitro. The formation of CML from ascorbate and lysine proceeds spontaneously at physiological pH and temperature under air. Kinetic studies indicate that oxidation of ascorbic acid to dehydroascorbate is required. Threose and N epsilon-threuloselysine, the Amadori adduct of threose to lysine, were identified in the ascorbate reaction mixtures, suggesting that CML was formed by oxidative cleavage of N epsilon-threuloselysine. Support for this mechanism was obtained by identifying CML as a product of reaction between threose and lysine and by analysis of the relative rates of formation of threuloselysine and CML in reactions of ascorbate or threose with lysine. The detection of CML as a product of reaction of ascorbate and threose with lysine suggests that other sugars, in addition to glucose, may be sources of CML in proteins in vivo. The proposed mechanism for formation of CML from ascorbate is an example of autoxidative glycosylation of protein and suggests that CML may also be an indicator of autoxidative glycosylation of proteins in vivo.
Ascorbic Acid↗
Synthesis of new nucleoside phosphoraziridines as potential site-directed antineoplastic agents.
With the aim of increasing the selectivity of the 2,2-dimethylphosphoraziridine type antitumor agents toward the intracellular site of DNA synthesis, a series of new compounds was synthesized in which the reactive bis(2,2-dimethyl-1-aziridinyl)phosphinyl (2,2-DMAP) group was linked through a carbamate or amide linkage to thymidine or cytosine nucleoside moieties. The 3'- and 5'-(2,2-DMAP)carbamates of thymidine (1 and 2) were found to be highly unstable, therefore the corresponding O-acetyl derivatives 5 and 6 were prepared by reacting 5'- and 3'-acetylthymidine, respectively, with dichloroisocyanatophosphine oxide followed by the addition of 2,2-dimethylaziridine and triethylamine. The 3'- and 5'-(2,2-DMAP)amides of thymidine 14 and 15 were prepared by reacting the appropriate thymidinylamines with bis(2,2-dimethyl-1-aziridinyl)phosphinyl chloride (17). The N4-(2,2-DMAP)amides of cytidine, 2'-deoxycytidine, and cytosine arabinoside (18, 19, and 20, respectively) were prepared by reacting the hydrochlorides of the O-peracetylated cytosine nucleosides with triethylamine and POCl3 and, subsequently, with 2,2-dimethylaziridine and triethylamine, to give the corresponding N4-(2,2-DMAP)cytosine nucleoside peracetates 21, 22, and 23, respectively, which were then deacetylated by aminolysis. However, the peacetate intermediates were found to be more stable and, probably for the same reason, also more active against P388 leukemia in mice than the deacetylated products. Particularly, 22 and 23 showed sufficient activity in this in vivo assay system to warrant further evaluation. The relationships between the antitumor activities, the chemical alkylating activities, and the cholinesterase inhibitory activities of these agents are discussed.
Alkylating Agents↗
Oxidation of glycated proteins: age-dependent accumulation of N epsilon-(carboxymethyl)lysine in lens proteins.
N epsilon-(Carboxymethyl)lysine (CML) has been identified as a product of oxidation of fructoselysine (FL) in glycated (nonenzymatically glycosylated) proteins in vitro and has also been detected in human tissues and urine [Ahmed et al. (1986) J. Biol. Chem. 261, 4889-4894]. In this study, we compare the amounts of CML and FL in normal human lens proteins, aged 0-79 years, using specific and sensitive assays based on selected ion monitoring gas chromatography-mass spectrometry. Our results indicate that the lens content of FL increases significantly between infancy and about age 5 but that there is only a slight, statistically insignificant increase in FL between age 5 and 80 (mean +/- SD = 1.4 +/- 0.4 mmol of FL/mol of Lys). In contrast, the lens content of the oxidation product, CML, increased linearly with age, ranging from trace levels at infancy up to 8 mmol of CML/mol of lysine at age 79. The ratio of CML to FL also increased linearly from 0.5 to 5 mol of CML/mol of FL between age 1 and 79, respectively. These results indicate that CML, rather than FL, is the major product of glycation detectable in adult human lens protein. The age-dependent accumulation of CML in lens protein indicates that products of both glycation and oxidation accumulate in the lens with age, while the constant rate of accumulation of CML in lens with age argues against an age-dependent decline in free radical defense mechanisms in this tissue.
Adolescent↗