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PubMed2004

Cotrel-Dubousset (CD) or Universal Spine System (USS) instrumentation in adolescent idiopathic scoliosis (AIS): comparison of midterm clinical, functional, and radiologic outcomes.

STUDY DESIGN: A retrospective comparison of the clinical, radiologic, and functional results of Cotrell-Dubousset (CD) and Universal Spine System (USS) instrumentation for adolescent idiopathic scoliosis (AIS). OBJECTIVES: To establish whether there are any differences in outcome between the 2 instrumentation systems. SUMMARY OF BACKGROUND DATA: CD is the first complex posterior double rod instrumentation system to provide multiple hook fixation. USS instrumentation permits the use of rod translation instead of rod rotation, the option to secure pedicle hooks with fixation screws, and the option to use transpedicular screws in the lower thoracic and lumbar spine. Midterm and long-term results of USS instrumentation are lacking. METHODS: Fifty-seven (mean age, 28 years at follow up) patients treated with CD instrumentation and 55 (mean age, 23 years at follow up) patients treated with USS instrumentation for AIS participated in the study. The average follow-up rate was 80% and time 13.0 years for the CD group, and 95% and 7.8 years for the USS group. Radiographs were obtained before surgery, at 2-year follow up, and at final follow up. Additionally, a physical examination was performed by 2 independent observers, and the Scoliosis Research Society (SRS) questionnaire was completed; spinal mobility and nondynamometric trunk strength were measured at the final follow-up visit. RESULTS.: The mean Cobb angle of the instrumented thoracic curve was before surgery 55 degrees (range, 36-83 degrees for the CD and 52 degrees (range, 35-85 degrees) for the USS group. The mean number of instrumented vertebrae was 9.9 (range, 7-12) in the CD and 9.8 (range, 6-12) in the USS group. At final follow up, the mean angles were 32 degrees (range, 13-63 degrees) for the CD group and 29 degrees (range, 9-63 degrees) for the USS group (not significant). No significant difference was observed in thoracic kyphosis or lumbar lordosis between the study groups at final follow up. In the SRS questionnaire, the total score averaged 97 for the CD and 101 for the USS groups, respectively. In the questionnaire, 6 (11%) patients in the CD group, but none in the USS group, reported having low back pain often or very often at rest. No correlation was found between the Cobb angle of the thoracic or lumbar curves at follow up and the total score or back pain indexes of this questionnaire. Nondynamometric trunk strength measurements corresponded with age- and sex-adjusted reference values, on average, but patients in the CD group performed significantly better in the squatting test (P = 0.021) and patients in the USS group performed better in trunk side bending (P = 0.004). Complications were recorded in 15 (26%) patients in the CD and in 13 (24%) patients in the USS group (not significant). CONCLUSIONS: The midterm radiologic and functional outcomes were quite similar in both groups as were the SRS scores. The patients performed, on average, as well as did the reference population in nondynamometric trunk strength measurements. Intraoperative and late complications were similar in both groups.

Adult↗

PubMed2006

On optimizing syntactic pattern recognition using tries and AI-based heuristic-search strategies.

This paper deals with the problem of estimating, using enhanced artificial-intelligence (AI) techniques, a transmitted string X* by processing the corresponding string Y, which is a noisy version of X*. It is assumed that Y contains substitution, insertion, and deletion (SID) errors. The best estimate X+ of X* is defined as that element of a dictionary H that minimizes the generalized Levenshtein distance (GLD) D (X, Y) between X and Y, for all X epsilon H. In this paper, it is shown how to evaluate D (X, Y) for every X epsilon H simultaneously, when the edit distances are general and the maximum number of errors is not given a priori, and when H is stored as a trie. A new scheme called clustered beam search (CBS) is first introduced, which is a heuristic-based search approach that enhances the well-known beam-search (BS) techniques used in AI. The new scheme is then applied to the approximate string-matching problem when the dictionary is stored as a trie. The new technique is compared with the benchmark depth-first search (DFS) trie-based technique (with respect to time and accuracy) using large and small dictionaries. The results demonstrate a marked improvement of up to 75% with respect to the total number of operations needed on three benchmark dictionaries, while yielding an accuracy comparable to the optimal. Experiments are also done to show the benefits of the CBS over the BS when the search is done on the trie. The results also demonstrate a marked improvement (more than 91%) for large dictionaries.

Algorithms↗

PubMed1995

Relationship of apolipoproteins AI, B and lipoprotein Lp(a) to hepatic function of liver recipients during the early post-transplant period.

To evaluate serum apo AI, apo B, Lp(a) and the ratio of unesterified cholesterol to total cholesterol as markers of hepatic synthetic capacity after orthotopic liver transplantation, serial measurements of these variables were performed on post-transplant days 1, 3, 5, 7, 10 and 14 in 70 patients. Liver function was assessed by a quantitative dynamic test based on the hepatic conversion of lidocaine to monoethylglycinexylidide (MEGX). Patients were divided into two groups on the basis of clinical and laboratory findings, those with evidence (n = 46) and those without evidence (n = 24) of hepatic dysfunction. Apo AI levels fell in both groups to day 5, but then began to increase in the group with good hepatic function, a highly significant (P < 0.001) positive correlation being found with the results of the MEGX test on post-transplant days 7, 10 and 14. The ratio of unesterified cholesterol to total cholesterol rose in both groups from days 1 to 7 and then began to fall in the group without hepatic dysfunction; a highly significant (P < 0.001) negative correlation was observed with the results of the MEGX test on days 10 and 14, Apo B levels rose in both groups from days 1 to 10, with no significant differences between the two groups; no correlation was observed with the results of the MEGX test on any study day.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2004

Variations in quality of frozen-thawed semen from Swedish Red and White AI sires at 1 and 4 years of age.

The predictability of semen quality of mature sires from measurements at an early age is not well established. The aim of the present study was to determine age-dependent changes in the quality of bull semen for artificial insemination (AI). Semen was collected and frozen from each of six Swedish Red and White (SRB) dairy AI bulls when they were 1 and 4 years old. Three batches were randomly selected from each bull and age group. From each batch, semen was analysed immediately after thawing [post-thaw (PT), control] as well as after washing/resuspension (W) and after a swim-up procedure (SU). The analyses comprised subjective and computerized (computer-aided sperm analysis, CASA) measurements of motility as well as sperm concentration, morphology and membrane integrity. When semen was analysed, PT, overall sperm motility (CASA), concentration of motile spermatozoa and membrane integrity improved when sires were older. After SU, there was a similar improvement in membrane integrity and concentration of motile spermatozoa, but linear motility decreased. No significant differences between ages were recorded after W-treatment. The above findings indicate that SU is not only superior to W-treatment in differentiating semen quality among bulls but also reveals age-dependent changes. Improved motility and membrane integrity suggest increased viability of spermatozoa at 4 years of age in the SRB sires examined here.

Aging↗

PubMed1987

Characterization of amyloid proteins AA and SAA as apolipoproteins of high density lipoprotein (HDL). Displacement of SAA from the HDL-SAA complex by apo AI and apo AII.

An AA-like protein with a molecular weight of 8600 complexed to high-density lipoprotein (HDL) was demonstrated in several acute-phase sera with high levels of SAA. The protein 'apo AA' (to distinguish it from tissue AA) was isolated by elution from sodium dodecyl sulphate (SDS)-polyacrylamide gel, and showed antigenic identity with purified tissue protein AA in double immunodiffusion. Normal HDL was shown to bind purified tissue AA in vitro. When the in vitro-associated HDL-AA complexes were given intravenously to mice during induction of amyloidosis, human AA was incorporated in the amyloid fibrils. Both apo AI and apo AII were shown to displace SAA from acute phase HDL when added to HDL-SAA complexes in vitro. This might be of importance in amyloidogenesis, as the liver and the small intestine, which are the main sites for AI and AII synthesis, are also sites of early amyloid deposition.

Acute-Phase Reaction↗

PubMed1985

A study of DNA polymorphisms around the human apolipoprotein AI gene in hyperlipidaemic and normal individuals.

We have used a 2.2 kb fragment of the human apolipoprotein AI (apo AI) gene to screen a number of unrelated individuals for common restriction fragment length polymorphisms (RFLPs) of the gene. As well as the previously reported SstI RFLP (allele frequencies in normolipidaemic individuals 0.94 and 0.06) we have detected RFLPs with the enzymes PstI and XmnI (allele frequencies in normolipidaemic individuals 0.88 and 0.12 for both polymorphisms). In the population studied, the RFLPs appear to be in linkage equilibrium and can be used in conjunction as a haplotype, with a PIC value (polymorphism information content) of 0.5. Significant differences in allele frequency were observed between subgroups of hyperlipidaemic patients and normolipidaemic controls. There is no strong population association in our patient group between any allele of the RFLPs studied and hypertriglyceridaemia.

Alleles↗

PubMed1994

Association between genetic variation at the APO AI-CIII-AIV gene cluster and familial combined hyperlipidaemia.

By using chemical cleavage mismatch analysis and the single strand conformation polymorphism technique, DNA fragments of the apo CIII gene, including the 5' flanking region and all the exons, were screened for sequence changes underlying the observed association between familial combined hyperlipidaemia (FCHL) and the apo AI-CIII-AIV gene cluster in affected individuals from eight FCHL families. A C1100-T transition in the wobble position of codon 14 in exon 3 and a T3206-G transversion in the non-translated region of exon 4 were identified, occurring in four and all probands, respectively. Using these variants and the G-75-A transition in the apo AI promoter, co-segregation of the gene cluster with hyperlipidaemia could be excluded in all eight families (lod score - infinity at theta = 0). No support for co-segregation was obtained using the affected pedigree member method of linkage analysis (overall T = -0.77 for f(p) = 1 [symbol: see text] p). The frequencies of T1100 and G3206 in a group of 55 patients with combined hyperlipidaemia were 0.35 and 0.52, respectively, which were significantly higher compared to 360 controls (0.21, p < 0.01 and 0.35, p < 0.005 respectively). In patients homozygous for the T1100 allele, levels of plasma triglyceride were 2.5-fold higher (868 mg/dl) than those homozygous for the C1100 allele (337 mg/dl), while patients heterozygous for the polymorphism had intermediate values (443 mg/dl) (p < 0.01). A similar association was seen in controls (p < 0.04). The three polymorphisms studied were in strong linkage disequilibrium in both the group of CHL patients and the unrelated individuals. This study confirms the association between common variation in the gene cluster and differences in plasma lipid levels in the general population and in patients with combined hyperlipidaemia, but fails to confirm co-segregation with FCHL, suggesting the role of other genetic or environmental factors in the aetiology of FCHL.

Adult↗

PubMed1995

Restriction fragment length polymorphisms at the apoprotein genes AI, CIII and B-100 and in the 5' flanking region of the insulin gene as possible markers of coronary heart disease.

Several sequence variations were examined for being endogenous "risk markers" in the development of CHD. The "markers" in this study included: the PstI-SstI RFLPs in the apo AI-CIII gene cluster, the EcoRI-MspI RFLPs in the apo B100 gene and the SstI RFLP in the 5' flanking region of the insulin gene. The study population comprised 700 individuals of German origin. A strong association of these "markers" to the disease phenotype predicts their loss in healthy individuals with ages above that of the prevalent incidence of CHD. In contrast, these "markers" should accumulate in diseased persons. A significant age-dependent selection was observed for the EcoRI RFLP in the apo B100 gene. This was the case when the allele and genotype frequencies of healthy old individuals were compared with those of newborns. In contrast, no RFLP showed significant differences in allele and genotype distributions between patients defined by coronary angiography and controls. In the group of patients, but not controls, several RFLP genotypes were found to be associated with significantly higher serum levels of cholesterol and triglycerides. This was true in the case of serum cholesterol comparing the genotypes S1S2 with those of S1S1 (p = 0.05) observed for the SstI polymorphic site in the 3' noncoding region of the apo CIII gene. Significantly higher levels of triglycerides were found within the heterozygous patients P1P2 (p = 0.045) and S1S2 (p = 0.02) than in the homozygotes P1P1 and S1S1 for the PstI-SstI RFLPs at the apo AI-CIII gene cluster.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1975

Purification of form AI and AII DNA-dependent RNA polymerases from rat-liver nucleoli using low-ionic-strength extraction conditions.

Recent findings have confirmed the role of form A DNA-dependent polymerase activity as that which is responsible for the transcription of the ribosomal RNA-coding genes. Unfortunately, the form A enzymes have proved to be very labile and difficult to work with, especially under high ionic strength conditions. We have, therefore, investigated a method for the purification of the form AI and AII enzymes from rat liver using mild low-ionic-strength conditions. Since preparations from whole nuclei were found to be grossly contaminated with protein having similar properties, the enzymes are extracted from nucleoli. Forms AI and AII are separated on a phosphocellulose column, purified by further ion-exchange chromatography, and by sedimentation through a glycerol gradient. The purified enzymes each migrate as a single band on native polyacrylamide gels and have the expected characteristics of form A RNA polymerase. Sedimentation rates through glycerol gradients indicate that they both have a similar size to that of Escherichia coli RNA polymerase (Mr about 500,000). The purified enzymes are free of DNase and RNase. A method is also described for the purification of form B from the nucleoplasm remaining after isolation of nucleoli. The presence of form C activity was not detected.

Animals↗

PubMed1989

Assessment of a PstI polymorphism of the apolipoprotein-AI gene in Australian patients with coronary artery disease.

In 1986 Ordovas et al., reported that a polymorphism in the 3' flanking region of the apolipoprotein AI gene was strongly associated with premature coronary artery disease. This polymorphism affects a restriction site for the endonuclease PstI, resulting in the identification of a 3.3 kb band, rather than the more common 2.2 kb band, when genomic blots of PstI digested human DNA are probed with an apolipoprotein AI gene probe. In a study population of 88 patients with severe coronary artery disease before the age of 60, 28 (32%) carried the 3.3 kb allele, which was found in only five (4%) of 123 randomly chosen control subjects. In the present study, we have assessed the prevalence of this polymorphism in coronary artery disease patients and outpatients with abnormal lipid levels at the Alfred Hospital, Melbourne, and in normal volunteers. The 3.3 kb allele was present in 7-12% of subjects in these populations, and showed no association with coronary artery disease.

Aged↗

PubMed1991

DNA restriction polymorphisms of the apolipoprotein AI-CIII-AIV gene cluster: a genetic determinant of atherosclerosis in type 2 (non-insulin-dependent) diabetes mellitus.

The presence of polymorphic restriction sites (S2, M2, P2) of the apolipoprotein AI-CIII-AIV gene cluster for the respective Sst1, Msp1, and Pst1 enzymes was assessed after hybridization with a radiolabelled apolipoprotein AI gene probe in 64 Type 2 diabetic patients and 67 healthy control subjects, all Europids. Twenty-two diabetic patients showed evidence of ischaemic heart disease or macrovascular arteriopathy and forty-two were free of cardiovascular complications. Control subjects were selected for the absence of personal or familial metabolic or cardiovascular diseases. The frequencies of polymorphic alleles were in agreement with previous studies in the control group: S2 6.3 (95% confidence interval (CI) 2.3-10.3) %, M2 5.5 (1.6-9.4) %, P2 6.3 (2.3-10.3) % and did not differ in the whole diabetic group: S2 4.2 (0.7-7.7) %, M2 6.5 (2.0-11.0) %, P2 6.6 (2.3-10.9) %. The relative prevalences of S2, M2, and P2 alleles were, respectively: 3.32, 1.54, and 2.00 (Woolf's ratio) in the macroangiopathic group but allele distribution frequencies were not statistically different from non-macroangiopathic patients. The allelic associations S2M2P1 and S1M1P2 showed a relative prevalence of 2.86 and 2.00 in the presence of cardiovascular complications but the difference was not significant in terms of polyallelic distribution frequencies in the absence of atherosclerosis. No serum lipid abnormalities could be related to the presence of any polymorphic allele or allelic association. These results suggest a genetic influence on the development of atherosclerosis in Type 2 diabetes, but the mechanism remains unclear.

Apolipoprotein A-I↗

PubMed1991

Lipoprotein lipids and apolipoproteins (AI, AII, B, CII, CIII) in type 1 and type 2 diabetes mellitus in young Kuwaiti women.

Plasma lipid and apolipoprotein levels of Type 1 and Type 2 young Kuwaiti diabetic women on insulin therapy were investigated to elucidate the relationship between coronary artery disease risk factors and lipid levels. Forty Type 1 and 52 Type 2 diabetic women and 45 and 62 corresponding control subjects (matched for age and body mass index) were investigated. In comparison with control subjects, both groups of diabetic patients showed marked increases in total-cholesterol, LDL-cholesterol, triglycerides, very low density triglycerides, apolipoprotein B, glucose, fructosamine, and glycosylated haemoglobin HbA1c (all p less than 0.001). However, apolipoprotein CIII was significantly elevated in Type 2 diabetic patients (p less than 0.001) but not in Type 1 patients. Concentrations of apolipoproteins CII and AII in both diabetic groups were not significantly different from those in control subjects. Levels of HDL-, HDL2- and HDL3-cholesterol and plasma apolipoprotein AI were markedly decreased in both the diabetic groups compared with their control groups (all p less than 0.001 except HDL3-cholesterol in Type 1 diabetic vs control, p less than 0.05). In Type 2 diabetic patients, HbA1c correlated positively with triglycerides (r = 0.70, p less than 0.001), cholesterol (r = 0.60, p less than 0.001), apolipoprotein B (r = 0.77, p less than 0.001), and apolipoprotein CIII (r = 0.55, p less than 0.001) and negatively with apolipoprotein AI (r = -0.49, p less than 0.001). In Type 1 diabetic patients HbA1c correlated positively only with apolipoprotein CIII (r = 0.50, p less than 0.001).

Adolescent↗

PubMed1995

Cladistic analysis of the apolipoprotein AI-CIII-AIV gene cluster using a healthy French Canadian sample. I. Haploid analysis.

A cladistic analysis was carried out to identify haplotypes hypothesized to differ for functional DNA sequence variations within the apolipoprotein (apo) AI-CIII-AIV gene cluster that affect plasma lipid, lipoprotein and apolipoprotein levels. A sample of unrelated healthy French Canadians was studied. First, a cladogram of the observed apo AI-CIII-AIV haplotypes was estimated. Then this cladogram was used to define a statistical analysis of the association between haplotype variation and variation in plasma lipid, lipoprotein and apolipoprotein levels. Three haplotypes were identified which were associated with small (5-12% of the total sum of squares) pleiotropic effects on plasma lipid, lipoprotein and apolipoprotein traits and these effects were context, i.e. gender, dependent.

Adult↗

PubMed1995

Prevalence of cholelithiasis according to alcoholic liver disease: a possible role of apolipoproteins AI and AII.

Moderate alcohol intakes decreases the risk of gallstones; in contrast, the prevalence of gallstones is increased in patients with alcoholic cirrhosis. The aims of this prospective study were to assess the prevalence of cholelithiasis among drinkers according to the histological severity of liver disease, and to estimate the importance of serum apolipoproteins AI and apolipoprotein AII as risk factors for gallstones. Among the 320 drinkers included, 53 patients had cholelithiasis. The prevalence increased (p < 0.0001) from 5% in patients with normal liver (1 of 22) and 6% in patients with steatosis only (3 of 47) to 13% in patients with fibrosis (7 of 54), reaching 27% among patients with biopsy-proven cirrhosis (28 of 103). Among patients with clinically obvious cirrhosis on whom biopsy was not performed mainly because of the severity of liver disease, the prevalence of cholelithiasis reached a maximum of 46% (6 of 13). Among drinkers with nonsevere liver disease, patients with cholelithiasis were older (59 +/- 9 years, mean +/- SD vs. 45 +/- 11, p = 0.003) with lower apolipoprotein AI (118 +/- 37 vs. 163 +/- 45 mg/dl; p = 0.002) and apolipoprotein AII (30 +/- 12 vs. 53 +/- 20 mg/dl; p = 0.0002) in comparison with patients without cholelithiasis. These differences persisted after considering by multiple logistic regression analysis, sex, and ideal body weight. Alcohol consumption during the last 5 years was lower in patients with cholelithiasis (83 g/day) in comparison with patients without cholelithiasis (142 g/day; p = 0.04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

A retinoic acid-responsive element in the apolipoprotein AI gene distinguishes between two different retinoic acid response pathways.

The gene coding for apolipoprotein AI, a plasma protein involved in the transport of cholesterol and other lipids in the plasma, is expressed predominantly in liver and intestine. Previous work in our laboratory has shown that hepatocyte-specific expression is determined by synergistic interactions between transcription factors bound to three separate sites, sites A (-214 to -192), B (-169 to -146), and C (-134 to -119), within a powerful liver-specific enhancer located in the region -222 to -110 nucleotides upstream of the apolipoprotein AI gene transcription start site (+1). In this study, it was found that site A is a highly selective retinoic acid-responsive element (RARE) that responds preferentially to the recently identified retinoic acid receptor RXR alpha over the previously characterized retinoic acid receptors RAR alpha and RAR beta. Control experiments indicated that a RARE in the regulatory region of the laminin B1 gene responds preferentially to RAR alpha and RAR beta over RXR alpha, while a previously described palindromic thyroid hormone-responsive element responds similarly to all three of these receptors. Gel retardation experiments showed that the activity of these RAREs is concordant with receptor binding. These results indicate that different RAREs may play a fundamental role in defining distinctive retinoic acid cellular response pathways and suggest that retinoic acid response pathways mediated by RXR alpha play an important role in cholesterol and retinoid transport and metabolism.

Adult↗

PubMed1988

High-density lipoprotein apolipoprotein AI and AII turnover in moderate and severe proteinuria.

The kinetic parameters of high-density lipoprotein (HDL) and its major apolipoproteins (Apo) AI and Apo AII were studied in 2 patients with moderate and severe proteinuria and 2 normal controls after intravenous injection of autologous 125I-HDL. The fractional catabolic rates (FCR) of HDL estimated by urine/plasma radioactivity ratio, and FCR of Apo AI and Apo AII calculated from the radioactivity decay curves were higher in the patients. These results support the concept that high-density lipoproteinuria and renal parenchymal sequestration of HDL found in the nephrotic syndrome contribute to accelerated HDL catabolism.

Adult↗

PubMed1989

Serum levels of apolipoproteins AI, AII and B in psoriasis.

Since an increased incidence of occlusive vascular disease has been reported in psoriasis, serum levels of apolipoproteins AI, AII and B were determined in 61 patients with the disease and compared with that of 34 healthy controls. No significant differences were found between the two groups. These findings suggest that the occurrence of thromboembolic disorders in psoriasis is not related to altered levels of apolipoproteins AI, AII, B in these patients.

Adolescent↗

PubMed1998

Evidence against linkage of familial combined hyperlipidemia to the apolipoprotein AI-CIII-AIV gene complex.

Familial combined hyperlipidemia (FCHL) was originally described as a disorder characterized by elevated levels of either plasma cholesterol or triglyceride (TG) or both in members ofthe same family. More recent studies have indicated that apolipoprotein B levels (apoB) are also elevated in these individuals. Although a dominant mode of inheritance was originally proposed, recent studies have questioned this simple mode of inheritance, and the genetic basis of the disorder has eluded investigators. A study that reported evidence that FCHL is linked to the apolipoprotein AI-CIII-AIV region on chromosome 11 is therefore of interest. We have attempted to replicate this finding in three large, well-characterized FCHL kindreds by using a highly polymorphic marker in the apoCIII gene. Using the same definitions and parameters as were used in the initial report, we obtained strong evidence against linkage of FCHL to the apolipoprotein AI-CIII-AIV region on chromosome 11 (combined lod score of -7.87 at 0% recombination). Two other models, one based on total cholesterol (TC) levels alone and one based on the joint distribution of TC and apoB levels, also gave evidence against linkage of FCHL to this region (lod scores at 0% recombination of -8.95 and -2.58, respectively). An additional regression-based linkage analysis also gave no support for the existence of a locus in this region that influences these lipid levels in these pedigrees. Explanations for the differences in results between these studies include genetic heterogeneity, differences in clinical phenotype used to select the pedigrees, and ascertainment bias.

Apolipoprotein A-I↗