Variation in lipoprotein(a) concentrations among individuals with the same apolipoprotein (a) isoform is determined by the rate of lipoprotein(a) production

Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein which is similar in structure to, but metabolically distinct from, LDL. Factors regulating plasma concentrations of Lp(a) are poorly understood. Apo(a), the protein that distinguishes Lp(a) from LDL, is highly polymorphic, and apo(a) size is inversely correlated with plasma Lp(a) level. Even within the same apo(a) isoform class, however, plasma Lp(a) concentrations vary widely. A series of in vivo kinetic studies were performed using purified radiolabeled Lp(a) in individuals with the same apo(a) isoform but different Lp(a) levels. In a group of seven subjects with a single S4-apo(a) isoform and Lp(a) levels ranging from 1 to 13.2 mg/dl, the fractional catabolic rate (FCR) of 131I-labeled S2-Lp(a) (mean 0.328 day-1) was not correlated with the plasma Lp(a) level (r = -0.346, P = 0.45). In two S4-apo(a) subjects with a 10-fold difference in Lp(a) level, the FCR's of 125I-labeled S4-Lp(a) were very similar in both subjects and not substantially different from the FCRs of 131I-S2-Lp(a) in the same subjects. In four subjects with a single S2-apo(a) isoform and Lp(a) levels ranging from 9.4 to 91 mg/dl, Lp(a) concentration was highly correlated with Lp(a) production rate (r = 0.993, P = 0.007), but poorly correlated with Lp(a) FCR (mean 0.304 day-1). Analysis of Lp(a) kinetic parameters in all 11 subjects revealed no significant correlation of Lp(a) level with Lp(a) FCR (r = -0.53, P = 0.09) and a strong correlation with Lp(a) production rate (r = 0.99, P < 0.0001). We conclude that the substantial variation in Lp(a) levels among individuals with the same apo(a) phenotype is caused primarily by differences in Lp(a) production rate.     

The dioxygenation rate in lipoxygenase catalysis is determined by the amount of iron (III) lipoxygenase in solution

The dioxygenation rate in reactions catalyzed by lipoxygenase-1 from soybeans has been measured as a function of the enzyme present in the Fe(III) form with rapid kinetic techniques. The experiments were carried out at pH 10, 25 degree C. The product concentration and the fraction of iron (III) lipoxygenase were monitored by measuring the absorbance at 243 nm and the tryptophan fluorescence at 330 nm (excitation at 287 nm), respectively. In reactions started with 1.3 microM iron (II) lipoxygenase and 9 microM linoleate, the initial rate, r(init) (estimated from the increase in absorbance over the initial 0.02 s of the reaction), is very small (4 s-1). In contrast, when the reactions are started with 1.3 microM (III) lipoxygenase, r(init) is large (150 s-1). In reactions started with mixtures of iron(II) and iron(III) lipoxygenase, r(init) is linearly related to the initial concentration of the Fe (III) enzyme form. Redistributions of the Fe(II) and Fe(III) enzyme forms during the reaction with 12 nM enzyme and 10, 50, or 100 microM linoleate appear to be directly reflected in changes in the dioxygenation rate. The observations provide solid evidence for the hypothesis that only iron (III) lipoxygenase can catalyze the hydrogen abstraction step in the dioxygenation reaction, and thus can be regarded as the active enzyme species. The observed dynamics are accurately predicted by a nonallosteric, two-step model for lipoxygenase catalysis [Schilstra et al. (1992) Biochemistry 31, 7692-7699].     

Measles virus DNA vaccination: antibody isotype is determined by the method of immunization and by the nature of both the antigen and the coimmunized antigen

Plasmids encoding the measles virus hemagglutinin (HA) and nucleoprotein (NP) proteins inoculated into the skin of BALB/c mice by the gene gun method induced both humoral and cytotoxic lymphocyte class I-restricted immune responses. Although intramuscular immunization induces the immunoglobulin G2a (IgG2a) antibody isotype for both antigens, with gene gun immunization, the NP still generated mainly IgG2a and the major isotype induced by the HA was IgG1. Interestingly, gene gun coimmunization of HA and NP plasmids resulted in a dominant IgG1 HA response and the switching of antibodies generated against the NP to the IgG1 isotype.     

Morphological properties of fast and slow PT cells in the cat revealed by intracellular pressure injection of HRP

Intracellular pressure injection of horseradish peroxidase (HRP) was applied to PT cells in the motor cortex of awake cats to reveal morphological properties. All PT cels recovered (N = 23) had pyramidal shaped somata located in layer V. All had apical dendrites going toward superficial layers and had basal dendrites spreading in layers V and VI. Fast and slow PT cells had axon collaterals which extended in layers V and VI. The spine density of fast PT cells in layer III was lower than that of slow ones as an average, but some fast PT cells had spines as many as slow ones. This was not in agreement with the previous report (Labelle and Deschênes16).) Morphological features to separate fast and slow PT cells were: (1)Fast PT cells had larger somata (20-50 micrometers in long axis) than slow PT cells (20-28 micrometers). (2)Horizontal spread of the dendritic field in layer V was larger in fast PT cells (mean : 654.7 micrometers) than in slow PT cells (mean : 222.0 micrometers).     

Development of the conduction system in the rat heart as determined by Leu-7 (HNK-1) immunohistochemistry and computer graphics reconstruction

BACKGROUND: The development of the heart conduction system is controversial. Our previous study demonstrated anti-Leu-7 antibody to cross-react with the cells of the conduction system in the embryonic rat heart. Thus, detailed analysis of the development of the conduction system was performed by immunohistochemical reaction with the use of the antibody. DESIGN: Horizontal serial sections of hearts obtained from embryonic and neonatal rats were treated for immunohistochemical reaction with anti-Leu-7 antibody, and three-dimensional images were reconstructed by computer graphics. Images were analyzed by superimposing the results on scanning electron micrographs. RESULTS: The development of the rat heart conduction system starts at 10 days and is completed by 18 days of gestation. The presence of three internodal tracts (INT1, -2, and -3) and two primordia of the atrioventricular node were confirmed in this process. INT1 and -3 pass through the septum spurium. INT2 follows the same route as the posterior internodal tract of James, but the other two INTs showed no correlation to previously described tracts. The sinuatrial node and INTs were found to be derivatives of the so-called S-A ring, and the bundle of His and bundle branches were found to be derived from the B-V ring. In this study, no immunoreactivity was observed in cells of the truncobulbar portion. CONCLUSIONS: Three internodal tracts and two atrioventricular node primordia were observed in the developing heart. The paths of the three internodal tracts showed intimate relationships with the internal structures of the heart. The developmental significance of the septum spurium, sinus septum, and venous valve was discussed.     

The Whorfian hypothesis and numerical cognition: is 'twenty-four' processed in the same way as 'four-and-twenty'?

Recent theoretical developments have redefined a Whorfian effect as a processing difference due to the language of the individual, and no longer as a marker for or against linguistic determinism. Within this framework. Whorfian effects can be used to investigate whether a particular part of the cognitive system is penetrable by language processes or forms an encapsulated module, provided the experimenter ensures that the target language difference is not caused by peripheral input or output processes. In this article, we examine the possibility of a Whorfian effect in numerical cognition by making use of the fact that in the Dutch number naming system the order of tens and units is reversed (i.e. 24 is read 'four-and-twenty'). In a first experiment, we asked native French- and Dutch-speaking students to name the solution of addition problems with a two-digit and a single-digit operand (e.g. 20 + 4 =?, 24 + 1 =?). The order of the operands was manipulated (20 + 4 vs. 4 + 20) as well as the presentation modality (Arabic vs. verbal). Three language differences emerged from this study. Experiment 2, however, showed that these differences were all due to input or output processes rather than differences in the addition operation (i.e. the differences between Dutch and French disappeared when subjects were asked to type the answer rather than pronounce it). On the basis of these findings, we question the idea that mathematical operations are based on verbal processes.     

Growth rate of lung metastases and S-phase fraction as determined by flow cytometry from the primary tumour in 25 patients with bone or soft-tissue sarcomas

A significant correlation (r = -0.48) was found between the logarithm of the S-phase fraction of the primary tumour (SPF) and the logarithm of the doubling time of lung metastases (T2). The estimated median cell loss factor was 88% (range 35-99%).     

High rates of genital mycoplasma infection in the highlands of Papua New Guinea determined both by culture and by a commercial detection kit

Duplicate vaginal swabs were collected from 100 women, and comparisons were made between an in-house broth-agar culture system and a commercially available kit, the Mycoplasma IST kit (bioMérieux), for the detection of Mycoplasma hominis and Ureaplasma urealyticum. There was good agreement between the two systems for detection of the genital mycoplasmas in terms of sensitivity, with values of > 92% being obtained. In terms of specificity, the mutual comparisons were less favorable, though specificity values of > 72% were obtained. Statistically there was no significant difference in the performance of the two tests (P < 0.1 for both M. hominis and U. urealyticum). While the broth-agar culture system was considerably less expensive than the kit, the Mycoplasma IST kit provided additional information on antibiotic susceptibilities and had the advantages of a shelf life of up to 12 months and not requiring the preparation of culture media. The prevalences of colonization obtained for M. hominis and U. urealyticum were extremely high in this randomly selected group of women from periurban and rural settlements in the Eastern Highlands of Papua New Guinea, being > or = 70% for M. hominis and > or = 78% for U. urealyticum. colonization with both genital mycoplasmas simultaneously was also very common, with > or = 60% of women being colonized by both M. hominis and U. urealyticum.     

Prognostic significance of tumor cell proliferation rate as determined by the MIB-1 antibody in breast carcinoma: its relationship with vimentin and p53 protein

L-929 cells acclimated to media made hyperosmotic (600 mosmol/kgH2O) by addition of NaCl, sorbitol, or mannitol show, on SDS-polyacrylamide gels, a markedly enhanced protein band at 40 kDa, most likely corresponding to the enzyme aldose reductase. The effect was not observed in cells acclimated to a medium rendered hyperosmotic by addition of proline. The major organic osmolyte accumulated is sorbitol in cells acclimated to high-sorbitol or high-NaCl medium, proline in cells acclimated to high-proline medium. Cells acclimated to any of these hyperosmotic media display unaltered Na+ levels and similarly increased K+ levels and decreased Cl-levels. These results are interpreted in terms of the mechanisms involved in aldose reductase induction and in regulation of the enzyme activity in long-term acclimation to hyperosmotic media.     

Genome size and GC-percent in vertebrates as determined by flow cytometry: the triangular relationship

Cortical dysplasia is a broad category for an abnormal structure of the cerebrum due to a disorder of the normal developmental process for neocortex. We investigated the cortical dysplastic lesions which were surgically resected from 4 patients with intractable epilepsy. All cases showed a derangement of the cortical laminar structure and dysplastic changes in the neurons. In addition, 3 of them showed large round cells (balloon cells) in the deep cortex and subcortical white matter. Since each lesion showed slightly different features, we further examined the lesions immunohistochemically by using a panel of antibodies against cytoskeletal proteins to recognize and classify the cortical dysplastic lesions. An immunohistochemical study revealed marked abnormalities of the cytoskeletal structures of dysplastic neurons, bizarre glial cells and balloon cells. These cells showed an accumulation of either phosphorylated NF, MAP2 or GFAP in a distinct fashion. Ubiquitin immunoreactivity highlighted the extent of cortical dysplastic lesions. In a young patient, we also found the neuronal cytoplasmic lipofuscin deposition. It is thus considered that these diverse immunohistochemical appearances of cortical dysplasia may thus imply a different pathogenesis and they should therefore be classified based on the extent of histological abnormalities.     

Ischemic preconditioning in the intact rat heart is mediated by delta1- but not mu- or kappa-opioid receptors

BACKGROUND: Our laboratory has previously shown that delta-opioid receptors are involved in the cardioprotective effect of ischemic preconditioning in the rat heart. However, this class of receptors consists of two subtypes, delta1, and delta2, and mu- or kappa-opioid receptors may also exist in the heart. Therefore, the purpose of the present study was to test the hypothesis that ischemic preconditioning is mediated through stimulation of one or both delta-opioid receptor subtypes. METHODS AND RESULTS: Anesthetized, open chest, male Wistar rats were assigned to 1 of 14 groups. All animals were subjected to 30 minutes of occlusion and 2 hours of reperfusion. Ischemic preconditioning was elicited by three 5-minute occlusion periods interspersed with 5 minutes of reperfusion. Two doses of 7-benzylidenenaltrexone (BNTX; 1 and 3 mg/kg i.v.), a selective delta1-opioid receptor antagonist, or naltriben (NTB; 1 and 3 mg/kg i.v.), a selective delta2-opioid receptor antagonist, were given before ischemic preconditioning. To test for a role of mu-opioid receptors, rats were pretreated with beta-funaltrexamine (beta-FNA; 15 mg/kg s.c), an irreversible mu-opioid receptor antagonist, 24 hours before ischemic preconditioning or given the mu-opioid receptor agonist D-Ala,2N-Me-Phe,4glycerol5-enkephalin (DAMGO) as three 5-minute infusions (1, 10, and 100 microg/kg per infusion i.v., respectively) interspersed with 5-minute drug-free periods before the prolonged ischemic and reperfusion periods (lowDAMGO, medDAMGO, and hiDAMGO, respectively). The involvement of kappa-opioid receptors was tested by administering one of two doses of nor-binaltorphimine (nor-BNI; 1 and 5 mg/kg i.v.) before ischemic preconditioning. Infarct size (IS) as a percent of the area at risk (AAR) was measured by triphenyltetrazolium stain. Ischemic preconditioning markedly reduced IS/AAR (14+/-4%, P<.05) compared with control (55+/-4%). NTB, beta-FNA, and nor-BNI were unable to block the cardioprotective effect of ischemic preconditioning. In addition, DAMGO had no effect on IS/AAR. However, the high dose of BNTX (3 mg/kg i.v.) significantly attenuated the cardioprotective effect of ischemic preconditioning (39+/-5%; P<.05 versus control and ischemic preconditioning). CONCLUSIONS: These results indicate that delta1-opioid receptors play an important role in the cardioprotective effect of ischemic preconditioning in the rat heart.     

Reactions of European wild boars (Sus scrofa scrofa L.) to running stress. 1. Behavior of respiratory and heart rate as well as the rectal temperature in standard tests of varying intensity and duration

Eight wild boars, aged between twelve and six months and weighing between 81 kg and 39 kg, all kept on floor surfaces and diets used also for domestic pigs, were exposed on a horizontally operated belt to three locomotor stresses which differed by intensity and duration. The speeds were 78 m/min in tests A and C and 138 m/min in test B. The time was limited to ten minutes in test A and 40 minutes in test C, whereas in test B the animals were kept running their rectal temperature had gone up to 41.5 degrees C. Rectal temperature, heart rate, respiratory frequency, as well as the electric diastole-systole quotient were measured in each of the tests. Described are the effects of both intensity and duration in terms of disturbance of the physiological equilibrium. The response produced by wild boar were compared with those recorded from domestic swine and yielded only slight superiority in physical fitness of wild boar.     

Hydrogen diffusion coefficients in the titanium alloys IMI 834, Ti 10-2-3, Ti 21 S, and alloy C

The diffusion coefficients of hydrogen were determined for three beta titanium alloys, which differ in the stability of the beta phase, and, for comparison, for one near-alpha titanium alloy in the temperature range from 40 °C to 500 °C. For this purpose, a step hydrogen concentration profile was produced by charging one side of rods of these materials with hydrogen by means of an electrochemical technique. After subsequent diffusion annealing, the hydrogen concentration profiles were determined analyzing small discs cut from these rods. The corresponding diffusion coefficient was calculated by adapting its value in such a way that a numerical diffusion simulation yields the experimentally determined profile. In all cases studied, the hydrogen diffusion coefficient was found to be independent of the hydrogen concentration and showed an Arrhenius-type temperature dependence. Hydrogen diffusion in alpha titanium was slower as compared to the beta titanium alloys under investigation. Furthermore, the diffusion coefficient of the metastable beta titianium alloys is only slightly affected by the prior heat treatment that determines the morphology and volume fraction of the precipitated alpha phase.     

Intracellular localization of p53 tumor suppressor protein in gamma-irradiated cells is cell cycle regulated and determined by the nucleus

DNA damage leads to the stabilization of p53 protein and its translocation to the nucleus, resulting in activation or suppression of p53-responsive genes. However, a significant proportion of cell nuclei remain negative for p53 and p53-inducible cyclin-dependent kinase inhibitor p21waf1 after a single dose of gamma-irradiation. Quantitation of DNA content in p53-positive and -negative nuclei 4-6 h after 10 Gy of gamma-irradiation of human breast carcinoma MCF7 cells, fibrosarcoma HT1080 cells, and diploid skin fibroblasts showed that p53 and p21waf1 nuclear accumulation occurs predominantly in the G1 phase and at the beginning of the S phase of the cell cycle. The majority of the nuclei in late S phase and in G2-M phase remained p53- and p21waf1-negative. This suggests that there is a cell cycle window during which p53 can accumulate in the nucleus and activate expression of p21waf1. To determine whether cell cycle-dependent distribution of p53 is caused by cytoplasmic modifications of p53 protein or by properties of the nucleus, p53 localization was analyzed in multinucleated cells obtained by polyethylene glycol-mediated cell fusion. Dramatic differences in p53 accumulation were found among the nuclei in individual multinucleated cells. Distribution of p53-positive and -negative nuclei among the phases of the cell cycle was similar to that observed in a regular cell population. These results suggest that the observed differences in p53 accumulation in the nuclei of irradiated cells are determined by cell cycle-dependent nuclear functions. In contrast to p53, p21waf1 was equally distributed among the nuclei of multinucleated cells regardless of the stage of the cell cycle, indicating that the observed phenomenon is specific for p53.     

Mitochondrial transmission during mating in Saccharomyces cerevisiae is determined by mitochondrial fusion and fission and the intramitochondrial segregation of mitochondrial DNA

To gain insight into the process of mitochondrial transmission in yeast, we directly labeled mitochondrial proteins and mitochondrial DNA (mtDNA) and observed their fate after the fusion of two cells. To this end, mitochondrial proteins in haploid cells of opposite mating type were labeled with different fluorescent dyes and observed by fluorescence microscopy after mating of the cells. Parental mitochondrial protein markers rapidly redistributed and colocalized throughout zygotes, indicating that during mating, parental mitochondria fuse and their protein contents intermix, consistent with results previously obtained with a single parentally derived protein marker. Analysis of the three-dimensional structure and dynamics of mitochondria in living cells with wide-field fluorescence microscopy indicated that mitochondria form a single dynamic network, whose continuity is maintained by a balanced frequency of fission and fusion events. Thus, the complete mixing of mitochondrial proteins can be explained by the formation of one continuous mitochondrial compartment after mating. In marked contrast to the mixing of parental mitochondrial proteins after fusion, mtDNA (labeled with the thymidine analogue 5-bromodeoxyuridine) remained distinctly localized to one half of the zygotic cell. This observation provides a direct explanation for the genetically observed nonrandom patterns of mtDNA transmission. We propose that anchoring of mtDNA within the organelle is linked to an active segregation mechanism that ensures accurate inheritance of mtDNA along with the organelle.     

Is autonomic control of the heart rate at rest altered by detraining? A study of heart rate variability in professional soccer players after the pretraining period and after the preparatory period for competitions

The aim of this study was to assess the influence of detraining and training on the autonomic control of heart rate (HR), using time and frequency (spectral analysis) domain components of heart rate variability. Sixteen professional football players (26.7 +/- 3.8 years; 74.9 +/- 4.1 kg; 177 +/- 6.3 cm) were analysed at the end of a 1 month holiday (detraining) and after a 6 week training period (training). HR was recorded over 15 minutes with Holter equipment. The athletes rested in a supine position, in a quiet place and all test were performed between 8 and 10 AM. The subjects were requested to refrain from meals or caffeine for 12 hours before testing. In spite of the high intensity of the training period, there was no significant change in results from detraining condition to training condition. These results can have two possible explanations: (i) the high level of cardiovascular capacity in the detraining trial originated by the recreative physical activity that the players underwent during their holidays, and/or (ii) the training period was not long enough to promote any relevant effect on the autonomic control of HR.     

Diffuse adherence, ST-I enterotoxin and CFA/IV colonization factor are encoded by the same plasmid in the Escherichia coli O29:H21 strain

Escherichia coli O29:H21 is a human enterotoxigenic serotype that produces heat-stable (ST-I) enterotoxin, adheres diffusely to HeLa cells, and presents colonization factor antigen IV (CFA/IV) composed of CS5CS6 surface antigens. In one strain studied the genes for diffuse adherence and CFA/IV (CS5CS6) production were found to be present in the same plasmid encoding ST-I. The virulence plasmid (Ent) presented two unrelated basic replicons homologous to repFIC and repW. Gene(s) encoding diffuse adherence did not share homology with the probe for F1845 fimbrial adhesin which is responsible for this phenotype in other E. coli strains. Ent plasmids containing genes for diffuse adherence have not been described previously.     

Investigation of the usefulness of CYFRA 21-1 as a tumor marker in squamous cell carcinomas of the head and neck

Compressive contact stress between the patella and the anterior femur and between the quadriceps tendon and anterior femur was measured before and after total knee arthroplasty in 5 cadaver knee specimens using a digital electronic sensor. Contact stresses were measured in the normal knee and after total knee arthroplasty with an unresurfaced patella, a dome-shaped patella, and a conforming patella. Patellofemoral contact stresses did not change significantly after total knee arthroplasty when the patella was not resurfaced, but they increased significantly after the patella was resurfaced with both the dome-shaped and the conforming components. The conforming patella had the highest contact stresses because it tilted at flexion angles greater than 90 degrees and applied load to a small area on the superior portion of the patellar component. The conforming patella markedly decreased tendofemoral contact force because the thicker superior pole of the patella tented the quadriceps tendon at flexion angles greater than 120 degrees. This further increased patellofemoral contact force in deep knee flexion.