Apolipoprotein H: a two-step isolation method

A new method for the purification of apolipoprotein H by affinity chromatography followed by continuous-elution electrophoresis is described. It is both simpler and less complicated than the chromatographic and electrophoretic methods usually used. In addition, apolipoprotein H is isolated in a pure, structurally uncleaved form. This is of importance, as impairment has been detected in commercial preparations. The separation and purification of apolipoprotein H is a necessary prelude to its quantitative determination and phenotyping, and hence the clarification of its physiopathological mechanisms in lipid metabolism.

Presence of different collagens and collagen mRNAs during embryogenesis and in adult tissues of the sea urchin Paracentrotus lividus

The presence of four different collagen genes had been previously described in the sea urchin genome and four different cDNAs had been cloned and sequenced. Two of them code for 140 and 300 KDaltons proteins, belonging to the fibrillar collagens, and the other two families code for two type IV collagens with a molecular weight of about 210 KDaltons. In this paper immunological evidence is provided for the presence in the developing P. lividus sea urchin embryo of at least seven major collagen proteins. Western blot analyses, carried out by means of specific polyclonal antibodies, show a series of collagenase sensitive bands, with molecular weights ranging from 55 to 200 KDaltons, which are present from eggs to plutei. Northern blot analyses show the presence of the previously described 6 and 9 Kb RNA bands from oocytes till plutei; in the later stages two other collagen RNAs are detected. The presence of two sets of genes coding for the 6 Kb mRNAs, differentially expressed during development, is also discussed. Immunofluorescence histological analyses show the location of collagen in gonads, oocytes, eggs, embryos and adult tissues.

Apolipoprotein E allele frequencies in an Italian population: relation to age and lipid profile

Apo E phenotype and plasma Tg, Chol, LDL-Chol, HDL-Chol and Apo B levels were determined in a sample of 228 healthy Italian subjects (124 men and 104 women) aged 18-93. The allele frequencies were: epsilon 2 = 0.070; epsilon 3 = 0.829; epsilon 4 = 0.101 (among the lowest values in the literature). Division of the sample into four age groups indicated that epsilon 4 frequency decreased with age to 0 in persons aged over 75. Covariance analysis of the influence of each allele on plasma lipids showed that epsilon 4 was significantly associated with the highest Chol, LDL-Chol and Apo B levels. These data are evidence of the influence of epsilon 4 on Chol metabolism in an Italian population. They also show that its frequency decreases with age.

Influence of apolipoprotein H polymorphism on levels of triglycerides

Human apolipoprotein H (apo H) displays a genetically determined structural polymorphism: three alleles (H*1, H*2 and H*3) on chromosome 17 code for the six phenotypes (three homozygotes and three heterozygotes). The effect of apolipoprotein polymorphism on individual variations in plasma lipoprotein levels has been underscored in recent years. Since apo H is involved in metabolism of triglycerides (Tg), its phenotype could affect Tg levels. This paper reports an investigation of apo H phenotypes in a sample of 217 subjects of the Italian population by means of isoelectrofocussing followed by immunoblotting. The levels of the main lipid parameters were evaluated in relation to phenotype and other influential factors. Analysis of covariance disclosed a significant association between Tg levels (log transformed) and phenotype (F = 8.27, P = 0.004). Comparison of Tg levels between bearers of the two most frequent phenotypes (H2/2 and H3/2) divided by sex and age classes revealed significantly higher levels in male H3/2 heterozygotes (P = 0.0053) and in H3/2 subjects aged less than 50 (P = 0.0095). Our data support the view that there is an association between hypertriglyceridaemia and apo H polymorphism, especially with the H*3 allele.

Bezafibrate affects lipid, lipo- and apolipoprotein pattern in non-insulin-dependent diabetic patients

To assess bezafibrate efficacy in a diabetic population a single-blind randomized study was performed in 32 diet-resistant type IIb hyperlipidaemic non-insulin-dependent (NID) diabetic patients in good metabolic control (HbA1c < 8%) compared to a placebo group. In our diabetic patients one month treatment of 400 mg/day bezafibrate lowered plasma C (-14%) and TG (-37%) and globally reduced the VLDL particles and VLDL lipids (-37% for C, -56% for TG and -25% for PL), raising VLDL C/TG ratio (+46%), redistributing TG from VLDL to LDL (+10%) and mainly in HDL (+49%), lowered LDL-C and Apo B levels and increased HDL-C together with Apo A1 (+19% and +13%) and Apo A1/Apo B (+72%). PL were raised by bezafibrate treatment and were redistributed from VLDL (-25%) to LDL (+25%) and HDL (+18%), while PL/C ratio increased in VLDL and in LDL (+18% and +50% respectively). Bezafibrate use was safe and improved the lipid pattern and the apolipoprotein and lipid distribution in the lipoproteins, producing a less atherogenic pattern in our NID diabetics.

Similarity of twins to singleton maternal serum alpha-fetoprotein ratio by race: no need to establish specific multifetal tables

The purpose of this study was to assess the need for race-specific maternal serum alpha-fetoprotein (MSAFP) curves in twin gestations. MSAFP values were evaluated in 535 samples obtained from twin gestations. Results were grouped according to gestational age (from 15 to 20 weeks), as with our singletons. Separate median curves were determined for black and for white pregnancies. On average, the median serum alpha-fetoprotein (AFP) for twins was about twice (2.1 +/- 0.3) the median of singletons. MSAFP in blacks was commonly higher than in white pregnancies of comparable gestational age. Using a 4.5 multiple of the singleton median cutoff in twin white pregnancies, 3.9% of the results were defined as 'high', similar to the rate observed in singleton pregnancies. 'Low' results in twins were defined as AFP values lower than 1.0 multiples of the singleton median (in pregnancies of similar gestational age and race). About 7% of the serum samples for whites were defined as 'low' by this criteria. Data for blacks were comparable. Race-dependent median values should be used for MSAFP interpretation in twin as well as singleton pregnancies. 'High' and 'low' percentages are comparable to our large data bank of singleton pregnancies and seem to be adequate for interpretation of serum AFP in twins. Therefore, the race-specific singleton multiples are sufficient, obviating the need to build specific median curves for multifetal gestations.

Hypercholesterolemia in non-insulin-dependent diabetes mellitus: different effect of simvastatin on VLDL and LDL cholesterol levels

Non-insulin-dependent diabetes mellitus (NIDDM) is often characterized by an increase in VLDL-triglyceride, VLDL-cholesterol, LDL-cholesterol and a reduction in HDL-cholesterol. HMG-CoA reductase inhibitors significantly lower cholesterol rates and have an indirect effect on the LDL receptor. We measured the effect of simvastatin in 28 hypercholesterolemic subjects, including 14 with NIDDM in good metabolic control (HbAIc 7.8% +/- 1.3%). A 24-week treatment with 10 mg/day (weeks 1-4), 20 mg/day (weeks 5-8) and 40 mg/day (weeks 9-24) simvastatin revealed different responses in diabetic and non-diabetic patients. Total cholesterol, LDL-cholesterol and apo B decreased significantly in both groups (less in the diabetics), whereas only NIDDM patients displayed a significant reduction in VLDL-cholesterol and VLDL-apo B. In the non-diabetics, the reduction in plasma cholesterol was mainly confined to the LDL fraction (276 +/- 65 vs. 132 +/- 28 mg/dl), whereas a significant fall in VLDL-cholesterol (45 +/- 19 vs. 21 +/- 10 mg/dl) was more evident in the NIDDM patients. Simvastatin also influenced plasma apo B levels (221 +/- 33 vs 134 +/- 23 mg/dl in non-diabetics and 182 +/- 44 vs. 134 +/- 30 mg/dl in diabetics). Significant reduction of apo B, LDL-apo B (205 +/- 39 vs. 128 +/- 23 mg/dl) in the non-diabetics and VLDL-apo B (16 +/- 5 vs. 9 +/- 2 mg/dl) in the diabetics, indicates that the VLDL are primarily concerned when statins are administered in NIDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression and purification of kringle 4-type 2 of human apolipoprotein (a) in Escherichia coli

The most frequently occurring kringle 4 domain of human apolipoprotein (a), Kringle 4-subtype 2 (K4(2)), was expressed as a fusion protein with the maltose binding protein in Escherichia coli using the "tac" promoter. Although the fusion protein was expressed without a signal sequence, 25% was secreted into the periplasmic space; the remainder was found associated with the soluble cytosolic fraction. The fusion protein was readily isolated from whole cell lysate by amylose agarose affinity chromatography. Although a factor Xa cleavage site was engineered into the fusion protein, it was found that release of the K4(2) protein was most conveniently achieved by proteolysis with subtilisin A. The cleavage product produced in this way was shown to be intact K4(2) with only the first three amino acid residues of the leading flanking peptide missing, as judged by N-terminal sequence analysis. K4(2) was isolated from the hydrolysate by FPLC on a Mono-Q column with a yield of 170 +/- 30 micrograms/g wet cells. The resulting protein was monomeric in phosphate-buffered saline as judged by size-exclusion chromatography and appeared to be folded as shown by spectroscopic and immunological assays. The recombinant K4(2) did not bind to either lysine- or proline-Sepharose, suggesting that the ligand binding activities of lipoprotein (a) may reside in the other kringle domains of apolipoprotein (a).

Comparison of the effects of bezafibrate and acipimox on the lipid pattern and plasma fibrinogen in hyperlipidaemic type 2 (non-insulin-dependent) diabetic patients

Correction of cardiovascular risk factors is of particular significance in a high-risk population, such as that of diabetic patients. This paper reports the effects of one-month administration of 400 mg/day Bezafibrate (BZF), followed by a two-month wash-out and one-month administration of 500 mg/day Acipimox (APX) or vice versa in a random order in 16 Type 2 diabetic patients with diet-resistant hyperlipidaemia and in good metabolic control (HbA1c less than 8%), on plasma fibrinogen and on their lipid pattern. Metabolic control displayed a nonsignificant improvement (HbA1c) during both treatments (stable body weight). Both BZF and APX produced a 14% decrease in total CHOL (p less than 0.01), whereas BZF was more effective in reducing triglycerides (tg) (-37% vs -15%). The marked BZF-induced Tg reduction was associated with a proportional decrease in Apo B, while an increase in total HDL-, HDL2 and HDL3-CHOL, together with a significant increase in Apo AI, was observed. APX treatment resulted in a HDL2-CHOL increase only (+29%). Both drugs reduced VLDL-CHOL (BZF -37%; APX -15%) and VLDL-Tg (-56% and -34%). In BZF treated patients Apo CIII fell indicating a possible reduction of specific inhibition of lipoprotein lipase activity, while APX affected both Apo CII (+23%) and Apo CIII (-26%) and led to a 62% Apo CII/CIII ratio increase. BZF alone led to a significant 25% decrease in plasma fibrinogen (from 415 +/- 14.3 to 312.1 +/- 18.1 SEM mg/dl, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoprotein-apolipoprotein changes in renal transplant recipients: a 2-year follow-up

Renal transplantation modifies the dyslipidemia characteristic of chronic renal failure (CRF). The change in lipoprotein and lipid values of 51 transplant recipients, on cyclosporine and corticosteroid treatment, was studied during 2 years after transplantation to examine the short- and medium-term variations of lipid metabolism. Compared with control values of (all in mg/dL) triglycerides (Tg) 111 +/- 44, very-low-density lipoprotein (VLDL) Tg 69 +/- 18, total cholesterol (Chol) 201 +/- 32, VLDL-Chol 32 +/- 9, low-density lipoprotein (LDL) Chol 118 +/- 28, and high-density lipoprotein (HDL) Chol 50 +/- 10, uremic patients pretransplantation exhibited values of Tg 200 +/- 82 (P less than .001), VLDL-Tg 133 +/- 70 (P less than .001), Chol 193 +/- 51 (NS), VLDL-Chol 52 +/- 16 (P less than .001), LDL-Chol 100 +/- 37 (P less than .007), HDL-Chol 40 +/- 16 (P less than .001), which changed to Tg 118 +/- 18 (P less than .001), VLDL-Tg 64 +/- 45 (P less than .001), Chol 223 +/- 48 (P less than .006), VLDL-Chol 26 +/- 33 (P less than .001), LDL-Chol 134 +/- 43 (P less than .001), at HDL-Chol 63 +/- 21 (P less than .001) at 3 months and Tg 135 +/- 76, VLDL-Tg 81 +/- 62, Chol 218 +/- 55, VLDL-Chol 22 +/- 20, LDL-Chol 139 +/- 46, and HDL-Chol 58 +/- 18 at 24 months without evidence of a significative variations in the 3- to 24-month posttransplant period.(ABSTRACT TRUNCATED AT 250 WORDS)

Managing for total quality in a large laboratory. Some examples

A large laboratory, processing more than 30,000 requisitions every 24 hours, provides a unique opportunity to document the value of selected approaches to managing for total quality. Proficiency test errors are an important subset of this database. They can provide a quality control manager with essential diagnostic information if data are analyzed in a systematic fashion. There is no benefit to performing proficiency tests in duplicate or in handling them in a manner different from patients. In fact, error rates can be higher when proficiency tests are handled in a special manner. Finally, error is decreased when technologists receive real-time feedback on how well the process is performing.

Cloning of a fibrillar collagen gene expressed in the mesenchymal cells of the developing sea urchin embryo

We have cloned and characterized several overlapping cDNAs that specify a large portion of a Paracentrotus lividus fibrillar collagen molecule. Our conclusions are based on sequencing data, which showed that the clones code for a 786-amino acid collagenous domain composed of an uninterrupted series of Gly-X-Y repeats and for a 265-amino acid carboxyl-terminal globular extension. The latter domain exhibits features highly reminiscent of those of the vertebrate counterparts, notably a putative carboxyl-peptidase cleavage site, a series of similarly arranged cysteinyl residues, and an N-linked glycosylation attachment site. In situ and Northern blot hybridizations have established the size, time of appearance, and tissue localization of the collagen mRNA during sea urchin development. The collagen transcript, 9 kilobases in length, is first detected in the primary and, more predominantly, in the secondary mesenchyme cells of late gastrulae where it progressively accumulates thereafter. This and other work (D'Alessio, M., Ramirez, F., Suzuki, H.R., Solursh, M., and Gambino, R. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 9303-9307) provide evidence of a genetic heterogeneity of fibrillar collagens in the sea urchin embryo and suggest that the two genes are activated in the same cell lineages at distinct developmental stages.

Structure and developmental expression of a sea urchin fibrillar collagen gene

We have isolated and characterized cDNA and genomic clones that specify a Paracentrotus lividus procollagen chain. The cDNAs code for 160 uninterrupted Gly-Xaa-Yaa triplets and a 252-amino acid carboxyl propeptide. Analysis of the deduced amino acid sequences indicated that the sea urchin polypeptide exhibits structural features that are characteristic of the fibril-forming class of collagen molecules. Partial characterization of two genomic recombinants revealed that the 3' end of the echinoid gene displays a complex organization that closely resembles that of a prototypical vertebrate fibrillar collagen gene. In situ and Northern (RNA) blot hybridizations established the size, time of appearance, and tissue distribution of the collagen transcripts in the developing sea urchin embryo. Collagen mRNA, approximately equal to 6 kilobases in size, is first detected in the forming primary mesenchyme cells of late blastulae where it progressively accumulates until the free swimming/feeding pluteus larval stage. Interestingly, collagen transcripts are also detected in the forming secondary mesenchyme cells of late gastrulae, and by the prism stage, their derivatives appear to be the most intensively labeled cells.

Isolation of a putative collagen-like gene from the sea urchin Paracentrotus lividus

Using a Caenorhabditis elegans collagen probe we have isolated a 17.6 kb clone from a Paracentrotus lividus genomic library. Sequencing of nearly 2.6 kb identified five open reading frames flanked at both sides by splice site consensus sequences and coding for ninety-five uninterrupted Gly-X-Y repeats. Interestingly, three of the putative exons exhibit sizes which are identical to those featured by vertebrate fibrillar collagen genes, namely 54 bp and 99 bp. Hybridization of the Gly-X-Y encoding sequences to RNA extracted from different developmental stages identified a specific 6 kb transcript, which appears first at mid-gastrula, greatly increases at prism and then progressively accumulates until pluteus stage. Based on these data, we conclude that the genomic clone is likely to code for a developmentally regulated mRNA whose expression coincides with the reported time of appearance of collagenous molecules in the sea urchin embryo.

alpha alpha alpha anti-4.2 Haplotype and heterozygous beta null thalassemia in a Sicilian family

The presence of the alpha alpha alpha anti-4.2 haplotype and heterozygous beta null thalassemia in a Sicilian family is described. These findings confirm the presence in Italy of a leftward deletion (-alpha 4.2) and indicate that this may not be rare. Furthermore, although the beta thalassemia determinant in this family has a severe expression, the interaction with the triplicated alpha gene does not necessarily express itself as thalassemia intermedia.