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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pancreatic islet volumes of patients with and without maturity onset diabetes mellitus were estimated. The islet volume of the diabetic patients was 1.01 +/- 0.12 cm3 (SEM) and that of the non-diabetic patients 1.60 +/- 0.16 cm3 with considerable overlap between the two groups. Islet amyloidosis was found in all the diabetic and in 9 of the 15 non-diabetic patients. When the amyloid deposits were excluded, the islet volume of the diabetic patients was 0.89 +/- 0.10 cm3, while that of the non-diabetic patients was unchanged, 1.60 +/- 0.16 cm3. There was still some overlapping. Since amyloid deposits seem to destroy the B cell membranes, it was postulated that a comparison of the volumes of islets completely free of amyloid might give a more true picture of the quantitative islet alterations in maturity onset diabetes. It was found that this islet volume of the diabetics was only 0.41 +/- 0.05 cm3 and that of the non-diabetic patients 1.58 +/- 0.16 cm3. These values correspond better to the altered insulin secretion in maturity-onset diabetes mellitus.
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PMID:The influence of amyloid deposits on the islet volume in maturity onset diabetes mellitus. 36 56

A risk of beta 2-microglobulin (beta 2-M)-associated amyloidosis in long-term CAPD patients has been recognised. We examined the kinetics of beta 2-M and potential clinical manifestations of amyloidosis in patients well-established on CAPD for 1-76 months (mean +/- SEM; 16.4 +/- 14 months). In 57 patients, serum beta 2-M concentration was elevated to 30 +/- 1.8 (mean +/- SEM, mg/l) and correlated positively with the duration on CAPD. In 18 patients studied with variable degrees of residual renal function, serum beta 2-M concentration increased with declining renal function; this was most marked when the creatinine clearance was less than 1 ml/min. Using an isosmolar solution (302 +/- 1.3 mOsm/kg) containing 5% glucose polymer (9.4 mmol/l; MW 16,800), the transperitoneal elimination of beta 2-M was significantly enhanced (1.6 times) compared to conventional 1.36% glucose solution, but without a detectable change in serum concentrations during a 6-h study. No significant difference was found between the estimated minimum volume of distribution of beta 2-M in CAPD and haemodialysis patients. Symptomatic amyloid-associated disease was absent in patients in this study, and may be attributed to the short duration of dialysis.
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PMID:Kinetic and clinical studies of beta 2-microglobulin in continuous ambulatory peritoneal dialysis: influence of renal and enhanced peritoneal clearances using glucose polymer. 213 Feb 98

The sequential changes in the concentration of specific serum proteins and their relation to amyloid A degrading activity were studied in ten patients with rheumatoid arthritis undergoing arthroplasty of the knee or hip. Serum amyloid A protein increased from a preoperative level of 78 +/- 20 gm/l (mean +/- SEM) to a peak level of 623 +/- 93 mg/l on the third postoperative day (P less than 0.001). The serum amyloid A protein response was greater than that of any other protein including C-reactive protein, to which it was closely related (r = 0.84, P less than 0.001). The concentrations of alpha 1-antitrypsin and alpha 1-antichymotrypsin were highest on the fourth postoperative day (mean changes + 35%, P less than 0.01, and +44%, P less than 0.05, respectively). Serum albumin, pre-albumin and alpha 2-macroglobulin behaved like negative acute phase reactants; the concentrations of albumin and alpha 2-macroglobulin were significantly decreased from the second to sixth and seventh postoperative days, respectively, and the concentration of pre-albumin was significantly decreased on the third and fourth postoperative days. A significant fall in the amyloid A degrading activity of serum occurred during the acute phase reaction. The degradative activity was lowest on the third and fourth postoperative days (P less than 0.001). The results show that the acute phase state in patients with rheumatoid arthritis induces a rise in the concentration of serum amyloid A protein, the putative serum precursor of tissue amyloid A fibrils, and a concomitant reduction in the ability of serum to degrade these fibrils. These factors together may be important in the development of inflammation-associated amyloidosis.
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PMID:The acute phase response and its relation to amyloid A degrading activity in serum of patients with rheumatoid arthritis undergoing arthroplasty. 619 91

Serum amyloid A (SAA) levels were studied in 35 recipients of cadaveric renal transplants. Marked SAA elevations were seen during all acute allograft rejection episodes. The mean peak SAA level in well-documented rejections was 446 mg/l (median 415 mg/l, range 132-1040 mg/l; controls less than 1 mg/l). Rejections in patients receiving cyclosporin-A alone as post-transplantation immunosuppressive medication were characterized by a significantly higher peak SAA level than rejections in patients receiving cyclosporin-A in combination with methylprednisolone (539 +/- 53 mg/l, mean +/- SEM, vs 226 +/- 9 mg/l, P less than 0.01). Excluding surgery-induced SAA elevations in the immediate postoperative period, seven significant SAA peaks not related to allograft rejection were observed. These were associated with surgical complications and infections, and in one case probably with the underlying rheumatic disease, which was complicated by amyloidosis. The results show that acute renal allograft rejection induces a dramatic acute phase SAA response. Since SAA is an easily measured serum component and the rejection-induced elevation is an early event, monitoring of SAA in kidney transplant patients may have considerable clinical significance.
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PMID:Serum amyloid A levels in human renal allograft rejection. 635 58

Enhanced extracorporeal removal of beta 2-microglobulin (beta 2m) may prevent the development of dialysis-related amyloidosis (DRA). One mechanism of beta 2m removal is membrane adsorption. Therefore, we fundamentally characterized beta 2m adsorption to the highly permeable polyacrylonitrile (PAN) membrane. Porous and nonporous PAN fragments were incubated in buffer containing 125I-beta 2m. Over a concentration range of 8 to 60 mg/liter, the equilibrium adsorption isotherm was linear (r = 0.99) for porous PAN while the isotherm for nonporous PAN suggested either multilayer binding or adsorption of proteins with differing orientations. In kinetic analyses, the approach to equilibrium versus (time)1/2 was evaluated. For both porous and nonporous PAN, this relationship was linear (r = 0.99), consistent with a diffusion-controlled process. Adsorption reversibility was assessed by comparing the amount bound at varying residence times (0 to 4 hr) to the amount remaining adsorbed after a subsequent incubation in buffer. The fractions remaining bound at 60, 120, and 240 minutes (0.34 +/- 0.02, 0.36 +/- 0.06, and 0.44 +/- 0.03; mean +/- SEM) were significantly greater (P < 0.05) than the value at five minutes (0.23 +/- 0.01). This suggests membrane-induced conformational changes in adsorbed beta 2m. This investigation permits the comparison of beta 2m adsorptive properties of PAN to those of other membrane-based and nonmembrane-based therapies designed to prevent DRA.
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PMID:Membrane adsorption of beta 2-microglobulin: equilibrium and kinetic characterization. 786 9

Increased biocompatibility and lower cost are the two major arguments favoring routine dialyzer reprocessing. The impact of longer-term reprocessing is critical to the practical use of polysulfone membranes (PMs), because of the possibility of decreasing efficiency and performance, especially in the removal of beta 2-microglobulin (beta 2M), a protein that has been implicated in the development of dialysis-associated amyloidosis (DDA). In this study, we examine urea clearance (Kd), urea mass transfer coefficient (h0), ultrafiltration coefficient (K(uf)), and percent removal of beta 2M up to 24 uses. The study involved 11 patients on hemodialysis for 5.27 +/- 4.6 years, with a mean age of 62.5 +/- 9.7 years and average run-time treatment of 2.78 +/- 0.3 hours. PMs were tested after being reprocessed manually using bleach and formaldehyde. The efficacy of the dialyzer was examined on uses 1, 5, 10, 15, 20, and 24, and the percent removal of beta 2M was determined except in the twentieth use and corrected for ultrafiltration. The Kd obtained through 24 uses showed no significant change, although h0 was significantly increased in the fifteenth use, and K(uf) was significantly increased in the 10th and 20th use (P < 0.05). The percent removal of beta 2M increased significantly from 44.1 +/- 2.8 (mean +/- SEM) in the first use to 59.4 +/- 2.19 (P < 0.05) in the 10th use, and 62.1 +/- 4.07 and 63.1 +/- 4.27 in the 15th and 24th uses, respectively (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of dialyzer reprocessing on performance and beta 2-microglobulin removal using polysulfone membranes. 846 21

Amyloid enhancing factor (AEF) is an operational term applied to poorly defined extracts of amyloidotic or preamyloidotic tissues capable of shortening the induction time of amyloid deposition in recipient mice from 1 to 2 weeks to 48 to 72 hours. Its derivation has always left open the question of whether activity was dependent on the presence of amyloid fibrils or preamyloid fibril fragments. In these studies, we have assayed AEF activity in extracts of spleen and liver from azocasein-injected rats and CE/J mice that do not develop amyloidosis and, hence, cannot have amyloid A (AA) fibrils or fibril fragments in their tissues. Susceptibility to amyloid induction was compared in three strains of mice and three strains of rats by subjecting each group of experimental animals to multiple injections of azocasein. Spleens and livers were removed 24 hours after the last injection, and samples of all tissues were examined for amyloid deposits. AEF was extracted from the remainder of the tissues taken from amyloid resistant CE/J mice and Sprague-Dawley rats. Graded doses of the resulting tissue extract were given to naive Swiss-Webster (SW) recipient mice by i.p. injection concomitantly with subcutaneous injection of 0.5 ml 2% AgNO3. All tissues from both CE/J mice and rat donor animals were negative for amyloid by histologic examination of Congo Red stained samples, as were the AEF extracts. All recipient mice (six of six) given 600 micrograms of the CE/J-derived AEF developed large amyloid deposits in their spleens (mean severity 3.7 -/+ 0.3 SEM). Lower doses (200 micrograms protein) resulted in similar incidence of amyloid accumulation (in four of five), but quantitatively smaller amounts of amyloid protein were present. Doses of 100 micrograms decreased incidence (in one of five), whereas animals receiving 50 micrograms were all negative. AEF derived from rat tissues also induced high incidence of amyloid (in four of five) at high doses, although the amount of AA protein was less than in mice given equivalent amounts of CE/J mouse-derived AEF. Although 200 micrograms and 100 micrograms of rat AEF was effective (in two of five and one of five, respectively), 50 micrograms did not result in demonstrable amyloid deposition. The presence of AEF in tissues from azocasein-treated amyloid-resistant rats and CE/J mice excludes the possibility that AEF activity may be due to the presence of amyloid fibrils or fibril fragments in the donor tissue.
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PMID:Amyloid enhancing factor is produced by rats and amyloid-resistant CE/J mice. 856 90

The usefulness of routine serum protein electrophoresis (SPEP) and urine protein electrophoresis (UPEP) screening in the evaluation of proteinuria is not known. The data on the clinical utility of these tests in 165 male patients with proteinuria greater than 3 g/d of protein who were screened for the presence of an M-spike are presented. Two hundred fifty-four studies were performed (SPEP, 155; UPEP 99) in these 165 patients. Twenty-four studies (9.8%) were positive for an M-spike (15 serum; 9 urine samples) in 19 patients (11.5%). Fourteen patients (8.5%) had an M-spike in either serum or urine, five patients (3%) in both studies. Two of these 19 patients were diagnosed with myeloma and 1 patient was diagnosed with primary amyloidosis. The other 16 patients were diagnosed with monoclonal gammopathy of unknown significance (MGUS). The group with a positive M-spike was significantly older (mean +/- SEM, 65 +/- 2 years; range, 39 to 78 years v 58 +/- 1 years; range, 25 to 84 years; P = 0.03), had a lower incidence of coexistent diabetes (21.1% v 61.6%; P = 0. 01), and a lower serum albumin level (3.2 v 3.6 g/dL; P = 0.05). Using a multivariable logistic regression model, the presence of an M band was positively correlated with age (odds ratio [OR], 1.056; 95% confidence interval [CI], 1.006 to 1.108) and negatively correlated for serum albumin level (OR, 0.386; 95% CI, 0.184 to 0. 810), hematocrit (OR, 0.923; 95% CI, 0.852 to 1.001), and the presence of diabetes mellitus (OR, 0.128; 95% CI, 0.038 to 0.434). In summary, routine SPEP and UPEP screening in patients with proteinuria greater than 3 g/d of protein detected an M-spike in 11. 5% and myeloma in 1.2% of the patients. The cost per case of myeloma or MGUS discovered was $1,192.
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PMID:Role of urine and serum protein electrophoresis in evaluation of nephrotic-range proteinuria. 1040 Oct 27

The formation and deposition of proteinaceous aggregates of amyloid fibrils characterize diverse degenerative diseases, such as Alzheimer's, Parkinson's, and systemic amyloidosis. The presence of these aggregates is associated with clinical manifestations, and various forms of amyloid aggregates have been identified to be cytotoxic. Although the exact mechanism of amyloid toxicity remains to be elucidated, prevention of amyloid fibril formation and aggregation forms a possible therapeutic approach. Nanomaterials possess the potential for such a strategy. Using hen egg white lysozyme (HEWL) as a prototypic amyloid-forming protein, we found a reduction in the aggregation rate of HEWL in the presence of super-paramagnetic iron oxide nanoparticles (SPIONs) with slowing of nucleation and amyloid fibril elongation. HEWL-amyloid had a predominantly fibrillar structure and was toxic to various cells. A significant attenuation of cytotoxicity was observed when cells were treated with SPION-interacted HEWL-amyloid. Ultra-structural differences were observed between the native and SPION-interacted HEWL-amyloids by SEM and TEM imaging. Our findings confirm that SPIONs perturb amyloid fibrillation, thereby reducing the cytotoxicity of amyloid.
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PMID:Attenuation of lysozyme amyloid cytotoxicity by SPION-mediated modulation of amyloid aggregation. 2556 31