Multiple molecular forms of serum α1-antitrypsin

Total soluble proteins, peroxidase, and peroxidase isozymes were examined in polyploid series of fern gametophytes and sporophytes. A distinctive pattern of protein bands was associated with gametophytes and sporophytes and the pattern did not vary within each phenotype with increases in the genome. Peroxidase activity per cell increased in direct proportion to increases in the genome and was determined to be gene dosage related. Slight differences in the patterns of peroxidase isozyme bands were associated with increases in the chromosome complement in both series of plants, but major variations were found between gametophyte and sporophyte. Quantitative analysis of peroxidase activity in each band revealed both increases and decreases in individual isozymes as ploidy increased. These findings suggest the involvement of regulatory mechanisms controlling isozyme activity.     

Is running performance enhanced with creatine serum ingestion?

Runners Advantage (RA) creatine (Cr) serum has been marketed to increase running performance. To test this claim, cross-country runners completed baseline testing (BASE), an outdoor 5,000-m run followed by treadmill Vo(2)max testing on the same day. Subjects repeated testing after ingesting 5 ml of RA (n = 13) containing 2.5 g of Cr or placebo (n = 11). Heart rate (HR), rating of perceived exertion (RPE), and run time were recorded. With RA (56.48 +/- 8.93 ml.kg(-1.)min(-1)), Vo(2)max was higher (p = 0.01) vs. BASE (54.07 +/- 9.36 ml.kg(-1.)min(-1)), yet the magnitude of the increase was within the coefficient of variation of Vo(2)max. No effect of RA on maximal HR was exhibited, yet Vco(2)max and duration of incremental exercise were significantly higher (p < 0.025) vs. BASE. Vo(2)max was similar in PL (58.85 +/- 6.67 ml.kg(-1).min(-1)) and BASE (57.28 +/- 7.22 ml.kg(-1.)min(-1)). With RA, the 5,000-m time was unchanged, and RPE was lower (p < 0.025) vs. BASE. These data do not support the ergogenic claims of RA in its current form and dose.     

Should we measure serum or plasma lead concentrations?

ProjectSerum samples may not be appropriate to assess lead (Pb) concentrations because they may contain artificially higher Pb concentrations compared with those measured in plasma samples. Here, we compared Pb concentrations in serum versus heparin plasma separated from blood collected with or without vacuum. We have also examined the effects of sample standing time on Pb concentrations measured in serum, heparin plasma, and EDTA plasma.ProcedureWe studied plasma and serum samples from twelve healthy subjects. Blood samples were collected via venous drainage phlebotomy with and without vacuum into trace metal free tubes containing no anticoagulants (serum), or lithium heparin, or EDTA (to obtain plasma). Variable sample standing times (0, 5, and 30 min) prior to centrifugation were allowed. Plasma and serum Pb and iron concentrations were determined by inductively coupled plasma mass spectrometry. Plasma and serum cell-free hemoglobin concentrations were measured.ResultsPb concentrations in serum and in heparin plasma from blood samples collected with or without vacuum were similar and not associated with significant changes in iron or hemoglobin concentrations. The sample standing time (up to 30 min) did not affect Pb concentrations in serum or in heparin plasma, which were approximately 50% lower than those found in EDTA plasma.ConclusionsSerum or heparin plasma separated from blood samples collected via venous phlebotomy with or without vacuum are appropriate medium to assess Pb concentrations, independently of the sample standing time.     

Purification and properties of human serum dopamine-β -hydroxylase

1. Two different molecular forms of dopamine-beta-hydroxylase were isolated from human serum; a major component (Peak I enzyme) with a molecular weight of 368000 and with a higher specific activity and a minor component (Peak II enzyme) with a molecular weight of 188000 and with a lower specific activity. 2. Both forms require ascorbic acid for the activity, and are stimulated by fumarate. Addition of N-ethylmaleimide or copper also increased the activity. The optimal pH of both forms in the presence of 20mM tyramine as substrate is 5.0. 3. Km values toward tyramine of Peak I enzyme and Peak II enzyme were 1.67 mM and 14.2 mM respectively. 4. Both Peak I enzyme and Peak II enzyme are glycoprotein.     

Contribution to the genetics of serum β-lipoproteins in man

Summary The genetic behaviour of a human serum -lipoprotein factor, called Ag(a₁), was studied by agar micro-diffusion technique, utilizing an antibody detected in the serum from a transfused thalassemia patient. It behaves as an inherited, dominant, autosomal character, with complete penetrance at birth. It is controlled by a gene and is closely linked to the Ag ^x and Ag ^y genes.The existence of a gene Ag ^b , allelic to , is postulated but the Ag(b) antigen has not so far been detected by specific antisera.The frequency of the gene in a Milan population was found to be 0,43, and in a Berne population was 0,46. The frequencies of the four possible gene combinations in the sample group from Milan were: Ag ^yb =0,53; =0,22; =0,21; Ag ^xb =0,04.The observed frequencies of the factor Ag(a₁) were 0,676 and 0,713, respectively among the Milan and Berne populations.     

Is there an interleukin 2 inhibitor in human serum?

Normal mouse serum has been shown to contain an inhibitor of interleukin 2 (IL-2). Here we report that a molecule with similar activity cannot be found in normal human serum (NHS). Although NHS inhibited the IL-2-dependent proliferation of mouse CTLL cells, as expected of an IL-2 inhibitor, it also had inhibitory activity on IL-3-dependent cells and was cytolytic to IL-2-independent mouse cells as measured by a ⁵¹Cr release assay, indicating a nonspecific effect. In addition, NHS had no effect on the IL-2-dependent proliferation of human peripheral blood T-cell blasts. Fractionation of NHS by size exclusion HPLC failed to separate cytolytic activity from any putative true IL-2 inhibitor activity. The cytolytic component was not related to immunoglobulin since it had a molecular weight of 50,000 to 60,000 and was not bound by protein-A-Sepharose. However, its molecular weight, heat lability, and trypsin sensitivity suggest it to be a protein.     

Contribution to the genetics of serum β-lipoproteins in man

Summary The study of 249 serum samples from blood donors of Berne, previously typed with respect to the Ag(x,y,a₁,d,c,g) factors has given preliminary evidence that the genes Ag ^a ₁ and Ag ^d, and Ag ^c and Ag ^g respectively are two pairs of co-dominant alleles. The locus Ag ^c/g appears to be closely linked with loci Ag ^x/y and Ag ¹¹/d .     

A putative “ribonucleic acid migration factor” in serum

Summary The processing of ribosomal ribonucleic acid (RNA) and the migration of newly synthesized RNA of several types from nucleus and nucleolus to the cytoplasm are restricted at 27°C. The previously reported failure of efforts to induce, glutamine synthetase at that temperature may be due to the retention by the nucleus of the specific RNA required for induction. At the normal temperature of 37°C serum macromolecules appear to be required for RNA migration. Cohn fraction III of bovine serum restores the RNA distribution pattern observed with whole serum. The exchange of lysine-labeled proteins between the cytoplasm and the nucleus is also altered by low temperature and in serum-free medium at 37°C. Supported by American Cancer Society Grant E-348 and United States Public Health Service Grant AI-00957     

Is serum HMGB1 a biomarker in ANCA-associated vasculitis?

Background

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are systemic inflammatory disorders that include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), Churg-Strauss syndrome and renal limited vasculitis (RLV). Extracellular high-mobility group box 1 (HMGB1) acts as an alarmin and has been shown to be a biomarker of disease activity as well as an autoantigen in systemic lupus erythematosus (SLE) and, possibly, in AAV. This study aims to assess antibodies against HMGB1 and HMGB1 levels as biomarkers for AAV disease activity and predictors of relapsing disease.

Methods

AAV patients with active disease and healthy controls (HC) were evaluated for anti-HMGB1 antibodies while serum HMGB1 levels were measured longitudinally in AAV patients at presentation, during remission, prior to and at relapses.

Results

HMGB1 levels were similar between AAV patients at presentation (n = 52) and HC (n = 35) (2.64 ± 1.80 ng/ml vs. 2.39 ± 1.09 ng/ml; P = 0.422) and no difference regarding HMGB1 levels could be found among AAV disease subsets (GPA: 2.66 ± 1.83 ng/ml vs. MPA: 3.11 ± 1.91 ng/ml vs. RLV: 1.92 ± 1.48 ng/ml; P = 0.369). AAV patients with renal involvement had lower HMGB1 levels than patients without renal involvement at presentation (2.35 ± 1.48 ng/ml vs. 3.52 ± 2.41 ng/ml; P = 0.042). A negative correlation was observed between HMGB1 levels and 24-hour proteinuria (ρ = -0.361, P = 0.028). Forty-nine AAV patients were evaluated for HMGB1 levels during follow-up and no differences were observed between relapsing and nonrelapsing patients (P = 0.350). No significant increase in HMGB1 levels was observed prior to a relapse compared with the remission period and changes in HMGB1 levels were not associated with an increased risk for relapse in AAV. Positivity for anti-HMGB1 antibodies was low in patients with active AAV (three out of 24 patients).

Conclusions

Serum HMGB1 levels at presentation are not increased and are lower in patients with renal involvement. Relapses are not preceded or accompanied by significant rises in HMGB1 levels and changes in HMGB1 levels are not related to ensuing relapses. Anti-HMGB1 antibodies are present in only a few patients in AAV. In contrast to SLE, HMGB1 is not a useful biomarker in AAV.     

Is serum gamma glutamyltransferase a marker of oxidative stress?

The primary role of cellular gamma glutamyltransferase (GGT) is to metabolize extracellular reduced glutathione (GSH), allowing for precursor amino acids to be assimilated and reutilized for intracellular GSH synthesis. Paradoxically, recent experimental studies indicate that cellular GGT may also be involved in the generation of reactive oxygen species in the presence of iron or other transition metals. Although the relationship between cellular GGT and serum GGT is not known and serum GGT activity has been commonly used as a marker for excessive alcohol consumption or liver diseases, our series of epidemiological studies consistently suggest that serum GGT within its normal range might be an early and sensitive enzyme related to oxidative stress. For example, serum and dietary antioxidant vitamins had inverse, dose-response relations to serum GGT level within its normal range, whereas dietary heme iron was positively related to serum GGT level. More importantly, serum GGT level within its normal range positively predicted F2-isoprostanes, an oxidative damage product of arachidonic acid, and fibrinogen and C-reactive protein, markers of inflammation, which were measured 5 or 15 years later, in dose-response manners. These findings suggest that strong associations of serum GGT with many cardiovascular risk factors and/or events might be explained by a mechanism related to oxidative stress. Even though studies on serum and/or cellular GGT is at a beginning stage, our epidemiological findings suggest that serum GGT might be useful in studying oxidative stress-related issues in both epidemiological and clinical settings.     

Contribution to the genetics of serum β-lipoprotein in man

Summary The study of some families of the double black cross type confirmed complete linkage of theAg ^x/y , andAg ^c/g loci.

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Zusammenfassung An Hand einer Untersuchung einiger Familien vom double back cross-Typ konnte das komplette linkage der Gen-LociAg ^x/y , undAg ^c/g bestätigt werden.

     

Ochratoxin A in human blood serum – retrospective long-term data

In a long-term study (1990–1997) on ochratoxin A (OTA) in human blood serum, 102 serum samples from 36 persons of the Munich Institute for Hygiene and Technology of Food of Animal Origin were analysed by enzyme immunoassay (EIA), and by high performance liquid chromatography (HPLC) for control. Detection limits were at 50 pg/ml (EIA) and 50–70 pg/ml (HPLC), recoveries were 80–120% (EIA) and 30–60% (LC). OTA was detected in 98% (EIA, 368 ± 217 pg/ml) and 93% (HPLC, 271 ± 170 pg/ml) of samples (maximum 1,290 pg/ml). Using published conversion factors for serum/intake estimates (1.34 or 1.97), the mean daily OTA intake of these 36 persons was 493–725 pg/kg bw. Long-term individual mean OTA levels of nine persons ranged from 162 ± 80 pg/ml to 549 ± 172 pg/ml. Our data were compared with published OTA serum levels (1985–2008) for apparently healthy persons from a total of 30 countries. On a worldwide basis, the mean of means for OTA in human serum was estimated to be 700 pg/ml, corresponding to a mean daily OTA intake of 940–1380 pg/kg bw. This level, which was relatively stable over the last decades, is well below published tolerable daily intake values (14,000–18,000 pg/kg bw).     

Why do omega-3 fatty acids lower serum triglycerides?

PURPOSE OF REVIEW: Fish oils rich in n-3 fatty acids reduce serum triglyceride levels. This well known effect has been shown to be caused by decreased very low-density lipoprotein triglyceride secretion rates in kinetic studies in humans. Animal studies have explored the biochemical mechanisms underlying this effect. Triglyceride synthesis could be reduced by n-3 fatty acids in three general ways: reduced substrate (i.e. fatty acids) availability, which could be secondary to increase in beta-oxidation, decreased free fatty acids delivery to the liver, decreased hepatic fatty acids synthesis; increased phospholipid synthesis; or decreased activity of triglyceride-synthesizing enzymes (diacylgylcerol acyltranferase or phosphatidic acid phosphohydrolase). RECENT FINDINGS: Rarely were experimental conditions used in rat studies physiologically relevant to the human situation in which 1.2% energy as n-3 fatty acids lowers serum triglyceride levels. Nevertheless, the most consistent effect of n-3 fatty acids feeding in rats is to decrease lipogenesis. Increased beta-oxidation was frequently, but not consistently, reported with similar numbers of studies reporting increased mitochondrial compared with peroxisomal oxidation. Inhibition of triglyceride-synthesizing enzymes was only occasionally noted. SUMMARY: As the vast majority of studies fed unphysiologically high doses of n-3 fatty acids, these findings in rats must be considered tentative, and the mechanism by which n-3 fatty acids reduce triglyceride levels in humans remains speculative.     

In serum veritas—in serum sanitas? Cell non-autonomous aging compromises differentiation and survival of mesenchymal stromal cells via the oxidative stress pathway

Even tissues capable of complete regeneration, such as bone, show an age-related reduction in their healing capacity. Here, we hypothesized that this decline is primarily due to cell non-autonomous (extrinsic) aging mediated by the systemic environment. We demonstrate that culture of mesenchymal stromal cells (MSCs) in serum from aged Sprague–Dawley rats negatively affects their survival and differentiation ability. Proteome analysis and further cellular investigations strongly suggest that serum from aged animals not only changes expression of proteins related to mitochondria, unfolded protein binding or involved in stress responses, it also significantly enhances intracellular reactive oxygen species production and leads to the accumulation of oxidatively damaged proteins. Conversely, reduction of oxidative stress levels in vitro markedly improved MSC function. These results were validated in an in vivo model of compromised bone healing, which demonstrated significant increase regeneration in aged animals following oral antioxidant administration. These observations indicate the high impact of extrinsic aging on cellular functions and the process of endogenous (bone) regeneration. Thus, addressing the cell environment by, for example, systemic antioxidant treatment is a promising approach to enhance tissue regeneration and to regain cellular function especially in elderly patients.     

Amino acid and carbohydrate compositions of human serum dopamine-β-hydroxylase

Dopamine--hydroxylase has been purified from human serum. The amino acid composition has been determined and found to be similar to that of the enzyme purified from human pheochromocytoma. Human serum dopamine--hydroxylase is a glycoprotein, containing 13.11 g carbohydrates/100 g protein. Individual sugar determinations showed the presence of fucose, galactose, glucose, mannose,N-acetylglucosamine,N-acetylgalactosamine andN-acetylneuraminic acid.     

Neuropeptides to replace serum in cryopreservation of mesenchymal stromal cells?

Background aimsThe therapeutic potential of human mesenchymal stromal cells (MSCs) has generated considerable interest in a wide variety of areas. MSC banking is feasible, but the optimal technique of cryopreservation remains to be determined.MethodsTo reduce dimethyl sulfoxide (DMSO) concentration in cryopreservation medium, DMSO was replaced with sucrose or trehalose. To increase cell survival and proliferation rates after thawing and to eliminate the need for fetal bovine serum (FBS), neuropeptides of the vasoactive intestinal peptide/glucose-dependent insulinotropic peptide/pituitary adenylate cyclase activating polypeptide family were added to the cryopreservation medium. Cell survival was analyzed by a trypan blue dye exclusion assay. Cell proliferation of cryopreserved MSCs was determined after 7 days of culture.ResultsNo significant differences in cell survival rates were detected between cryopreservation solutions with 5% and 10% DMSO, independently of the addition of trehalose or sucrose. Cell proliferation rates tended to be highest when MSCs were frozen in 5% DMSO + trehalose. FBS could be replaced by human albumin (HA) without loss in cell survival and proliferation potential. With FBS, the addition of neuropeptides could increase cell survival and proliferation rates. Without FBS or HA, cell survival and proliferation rates in the presence of neuropeptides were comparable to rates achieved with FBS or HA.ConclusionsClassic cryopreservation with 10% DMSO could be replaced by 5% DMSO + 30 mmol/L trehalose. FBS could be replaced by HA or neuropeptides without loss in cell survival and proliferation potential. The addition of neuropeptides in the cryopreservation medium containing FBS could increase the cell proliferation rate and consequently cellular output.     

Why do cancer cells produce serum amyloid a acute-phase protein?

The level of acute-phase serum amyloid A (SAA) protein in human blood dramatically grows in cancer, often at its early stage, when acute inflammatory signs are not observed. This fact was registered both by immunochemistry and by proteomics methods in different common cancers, such as lung, ovarian, renal, uterine, and nasopharyngeal cancer and in melanoma. It was proposed that SAA is produced by liver in such cases, as in inflammation, high levels of SAA being a part of nonspecific response to tumor. However, that was not always true, because, in many cancers, the protein of interest is produced directly by cancer cells. What is the biological significance of this observation? What preferences do cancer cells obtain due to SAA overexpression? Recent data on melanoma patients have shown that serum amyloid A is able to stimulate immunosuppressive neutrophils to produce interleukin-10 cytokine that suppressed cell immunity. The ability of cancer cells to produce SAA that is acquired during cancer mutagenesis is likely to enhance their resistance to T-cell immunity due to activation of immunosuppressive granulocytes.     

Contribution to the genetics of the serum β-lipoproteins in man

A study was made of the genetic behaviour of the factors Ag(x) and Ag(y) of the β-lipoproteins of human serum. It was found that these factors are controlled by a single pair of autosomal codominant genes with complete penetrance at birth. The gene frequencies were:

$$\begin{gathered} Milan . . . . Ag^x = 0,23 Ag^y = 0,77 \hfill \\ Berne . . . . Ag^x = 0,24 Ag^y = 0,76. \hfill \\ \end{gathered}$$