At least six forms of extremely homologous cytochromes P-450 in rat liver are encoded at two closely linked genetic loci.

A subpopulation of phenobarbital-induced cytochrome P-450 in rat liver has been shown to consist of four closely related forms of the enzyme that appeared to be strain-related. In the present study, polypeptides composing this family were analyzed by two-dimensional electrophoresis of hepatic microsomes from 64 individual phenobarbital-treated rats. The animals surveyed included both sexes from four inbred and five outbred strains/colonies and F1 progenies from 10 crosses. Two new members of this polypeptide family were identified on the basis of their unique electrophoretic behavior and peptide maps. Eight phenotypes were observed that consisted of two to four member polypeptides. The six closely related cytochromes P-450 were found to be encoded at two genetic loci with at least four alleles at the P-450b locus and at least two alleles at the P-450e locus. Most colonies of outbred strains were characterized by polymorphism at one or both of these loci, and in no case did they contain unique alleles. Analyses of parents and their F1 progenies indicated that the P-450b and P-450e loci are closely linked on the same autosome and are expressed codominantly. Furthermore, the products of these loci appear to be coordinately regulated. The extreme homology between P-450b and P-450e genes, their high degree of polymorphism, and their close linkage suggest that they are subject to the same genetic mechanisms that maintain these features in other multigene families.     

Genetically determined polymorphism of the circulating human breast cancer-associated DF3 antigen

The murine monoclonal antibody (MAb) DF3 was prepared against a human breast carcinoma. Previous studies have demonstrated that DF3 antigen levels are elevated in plasma of patients with breast cancer. Furthermore, MAb DF3 reacts with circulating glycoproteins of different molecular weights ranging from approximately 300 to 450 kd. The present study demonstrates that plasma DF3 antigen is comprised of at least four moieties with slow (S), intermediate (I), rapid (R) and very rapid (VR) electrophoretic mobilities. The electrophoretic mobility patterns for circulating DF3 antigen differ among individuals. Moreover, DF3 antigen is detectable in urine, and the electrophoretic mobility of the urinary moieties is similar, but not identical, to that in the plasma. Studies in family members suggest that the electrophoretic heterogeneity of plasma DF3 antigen is determined by codominant expression of multiple alleles at a single locus. This locus may code for the core protein of DF3 antigen. These findings thus identify a genetically determined polymorphism of a circulating tumor-associated glycoprotein.     

Peroxidase complex with concomitant anodal and cathodal variation in red-fruited tomato species

Four groups of bands (a-d) are controlled by 19 alleles of the Peroxidase-4 (Prx-4) complex in the red-fruited tomato species, Lycopersicon esculentum and L. pimpinellifolium. Heterozygotes can be detected by virtue of codominance in all combinations except a few in which bands of single groups are absent (“semi-null” alleles). No recombinations were detected in 7419 F₂ segregants of 53 different combinations of alleles. A maximum fiducial limit (P = 0.01) of 0.08% crossing-over between any Prx-4 band groups is estimated. Variation of the anodal b bands is absolutely associated with that of the cathodal d band in respect to presence versus absence and direction of migration. In respect to the origin of these variants, the probability of 18 instances of simultaneous mutation of genes at two loci, always in such complete agreement, is so remote that no more than one locus could conceivably govern b and d. The disposition of a is not similarly associated with that of the other bands, while that of the faint-staining c could not always be reliably resolved. The negation of all save extremely low recombination rates and the observed concomitant variation of b and d strongly support the concept of single locus control of all Prx-4 banding, this hypothesis being espoused until rejection should be required be required by future research. Models of single locus control of several isozymes are discussed.     

Ventricular tachyarrhythmia initiation in a canine model of recent myocardial infarction. Comparison of unipolar cathodal, anodal and bipolar stimulation

Ventricular tachyarrhythmia initiation was compared using unipolar cathodal, anodal and bipolar programmed stimulation at 21 sites in 5 normal adult mongrel dogs and 67 noninfarct sites in 16 dogs 3-5 days after experimental myocardial infarction. For this purpose, the minimum number of extrastimuli required for tachyarrhythmia initiation was determined in each pacing mode using twice cathodal threshold current for the drive beats and all extrastimuli except the last. The current and pacing mode were varied for the last extrastimulus (S2, S3 or S4). In the 5 normal dogs, ventricular fibrillation was reproducibly inducible from only 1/21 sites, and only in the cathodal mode. In 15/16 (94%) of the myocardial infarction dogs, a sustained ventricular tachycardia or ventricular fibrillation could be reproducibly initiated with either one (4 dogs), two (5 dogs) or three extrastimuli (6 dogs). Diastolic excitability thresholds were 0.08 +/- 0.03, 0.30 +/- 0.17, and 0.09 +/- 0.04 mA (median +/- SD) for unipolar cathodal, anodal and bipolar pacing, respectively (p less than 0.001 for anodal vs. cathodal and bipolar). The median absolute current required for ventricular tachyarrhythmia initiation was also highest with anodal pacing (0.72 +/- 0.77 mA), versus both the cathodal and anodal modes (0.18 +/- 0.28 and 0.20 +/- 0.28 mA, respectively, each p less than 0.001) but was comparable in all three modes relative to the threshold current (2.0, 2.4 and 2.6 mA for cathodal, anodal and bipolar pacing, respectively) required for initiation. Overall, ventricular tachyarrhythmia initiation was concordant in all three modes at 58/67 (87%) sites and discordant at only 9/67 (13%) sites (p less than 0.001). Moreover, there was no difference in either the pattern of arrhythmia initiated in each of the pacing modes with respect to ventricular tachycardia versus ventricular fibrillation, or in the median current required to initiate ventricular tachycardia (0.30 +/- 0.36 mA) versus ventricular fibrillation (0.31 +/- 0.44 mA; p greater than 0.1). Thus, ventricular tachyarrhythmia initiation was comparable in all three pacing modes with respect to overall success rate, number of ventricular extrastimuli required and the pattern of ventricular tachyarrhythmia initiated. Bipolar pacing with similar size anodal and cathodal electrodes appear to be appropriate for electrophysiologic ventricular tachyarrhythmia studies and are not likely to induce spurious arrhythmias resulting from stimulation at the anodal pole.     

Extent of genetic variation at a highly polymorphic esterase locus in Drosophila pseudoobscura.

The esterase-5 locus of Drosophila pseudoobscura has been screened for variation by using a wide variety of electrophoretic conditions and by testing heat sensitivity. Among 50 isogenic lines from 17 populations, 21 genetic variants were found at the locus, 18 by electrophoresis and 3 by heat denaturation. Including alleles previously known, there are a total of 30 alleles at this locus in natural populations. This represents a doubling of the previous estimates of polymorphism at this locus. The study confirms that, in contrast to monomorphic loci, loci judged polymorphic under one detection procedure show large increases in polymorphism when examined extensively.     

Genome wide association study for plasma levels of natural anticoagulant inhibitors and protein C anticoagulant pathway: the MARTHA project

Deficiencies of antithrombin (AT), protein C (PC) and protein S (PS) or an impaired PC anticoagulant pathway increase the risk of venous thrombosis (VT). By conducting a genome-wide association study (GWAS) on two independent samples of VT patients totalling 951 subjects typed for 472 173 single nucleotide polymorphisms (SNPs), we observed that common SNPs explain 21% and 27% of the genetic variance of plasma AT and PS levels, even though no SNP reached genome-wide significance. For PC, we showed that two PROCR SNPs, rs867186 (Ser219Gly) and rs6060278, additionally explained c. 20% (P = 1·19 × 10(-31)) of the variance of plasma PC levels. We also observed that c. 40% of the remaining genetic variance of PC levels could be due to yet unidentified common SNPs. The PROCR locus was also found to explain c. 8% (P < 10(-10)) of agkistrodon contortrix venom (ACV) (exploring the PC pathway) variability which was under the main control of the F5 and F2 loci that further explained about 40% and 10%, respectively. We presented here the first GWAS for plasma AT and free-PS levels and ACV in Caucasian samples. We identified three independent loci associated with ACV (F2, F5 and PROCR) and replicated two independent effects on plasma PC levels at the PROCR locus.     

Inherited structural polymorphism of the fourth component of human complement.

Human fourth component of complement (C4) was found to be highly polymorphic by agarose gel electrophoresis of neuraminidase-treated plasma. The system allows clear-cut separation of the products of the two C4 genetic loci, C4A (acidic or Rodgers) and C4B (basic or Chido). There are at least six structural variants and a deletion allele at the C4A locus and two structural variants and a deletion allele at the C4B locus. Close linkage with no crossovers was found between the two C4 loci, allowing the definition of C4AB haplotypes, and between C4 haplotypes and the C2 and BF loci of the human histocompatibility complex. Nine C4 haplotypes, each with a frequency of 0.005 or more in Caucasians, were found. These studies provide direct evidence for two distinct but closely linked genetic loci for human C4 in the major histocompatibility complex on the short arm of chromosome 6.     

Murine binding protein of the fourth component of complement: structural polymorphism and its linkage to the major histocompatibility complex.

The binding protein of the fourth component of complement (C4-BP) is a regulatory protein of the complement system with specific affinity for the fourth component. This paper describes a structural polymorphism of murine C4-BP and its linkage to the major histocompatibility complex of the mouse (H-2). After isoelectric focusing of whole mouse plasma in low-endosmosis agarose, C4-BP was demonstrated as a single precipitin band by overlaying monospecific antiserum on the agarose gel. Two C4-BP patterns were distinguished among many strains of mice on the basis of isoelectric point--C4-BP a type, which has a pH range of 6.5-7.0 (exemplified by B10.BR and B10.AKM), and C4-BP b type, which has a pH range of 6.3-6.6 (exemplified by B10 and B10.M). Genetic crosses between two strains bearing distinct C4-BP types demonstrate a C4-BP pattern representative of both types. A linkage study was carried out in which progeny of two backcross combinations--[(B10 X B10.BR)F1 X B10.BR] and [(B10.AKM X B10)F1 X B10.AKM]--were phenotyped for C4-BP type and serum fourth-component level. Results were obtained suggesting that C4-BP patterns are inherited by a single codominant locus (C4-Bp) linked to the H-2 complex. The recombination frequency between the C4-Bp locus and the S region was 0.017. By phenotyping appropriate intra-H-2 recombinants of three different backgrounds (B10, A, and HT), this locus was assigned to the right of the H-2D region.     

Deletion mapping of genetic regions associated with apomixis in Hieracium

Although apomixis has been quoted as a technology with the potential to deliver benefits similar in scale to those achieved with the Green Revolution, very little is currently known of the genetic mechanisms that control this trait in plants. To address this issue, we developed Hieracium, a genus of daisies native to Eurasia and North America, as a genetic model to study apomixis. In a molecular mapping study, we defined the number of genetic loci involved in apomixis, and we explored dominance and linkage relationships between these loci. To avoid difficulties often encountered with inheritance studies of apomicts, we based our mapping effort on the use of deletion mutagenesis, coupled with amplified fragment length polymorphism (AFLP) as a genomic fingerprinting tool. The results indicate that apomixis in Hieracium caespitosum is controlled at two principal loci, one of which regulates events associated with the avoidance of meiosis (apomeiosis) and the other, an unlinked locus that controls events associated with the avoidance of fertilization (parthenogenesis). AFLP bands identified as central to both loci were isolated, sequenced, and used to develop sequence-characterized amplified region (SCAR) markers. The validity of the AFLP markers was verified by using a segregating population generated by hybridization. The validity of the SCAR markers was verified by their pattern of presence/absence in specific mutants. The mutants, markers, and genetic data derived from this work are now being used to isolate genes controlling apomixis in this system.     

A 1.5-megabase yeast artificial chromosome contig from human chromosome 10q11.2 connecting three genetic loci (RET, D10S94, and D10S102) closely linked to the MEN2A locus.

The genetic loci RET, D10S94, and D10S102 from human chromosome 10q11.2 are very closely linked to a locus responsible for the multiple endocrine neoplasia type 2 (MEN2A and MEN2B) and medullary thyroid carcinoma (MTC1) familial cancer syndromes. We have constructed a 1.5-megabase contig consisting of six genomic yeast artificial chromosome clones which include these loci and define their physical order. A critical crossover event has been identified within the map interval; this event places the MEN2A locus centromeric to D10S102 and defines the orientation of the physical map on the chromosome. The orientation of the contig and order of the markers are centromere-RET-D10S94-D10S102-telomere. In addition, a microsatellite repeat polymorphism with a heterozygosity of 71% at the RET locus and a restriction fragment length polymorphism with a heterozygosity of 42% detected by a lambda clone from the D10S94 locus have been developed for high-resolution genetic linkage mapping and predictive diagnostic testing. These data place three important markers on a contiguous physical map, narrow the MEN2 disease locus interval, and provide a framework for further candidate gene identification efforts. Placement of these genetic loci along a clone-based map and continued expansion of the contig will also facilitate efforts to determine the relationship of physical to genetic distance near the centromeres of human chromosomes.     

Genetic polymorphism of human liver alcohol and aldehyde dehydrogenases, and their relationship to alcohol metabolism and alcoholism

It is now widely accepted that the various pharmacologic and addictive consequences of alcohol consumption are related to the tissue concentration of ethanol or its metabolic products. The oxidative metabolism of ethanol in liver is principally catalyzed by alcohol dehydrogenase and aldehyde dehydrogenase. Both of these enzymes exist in multiple molecular forms, and genetic models have been proposed to account for the multiplicity of isoenzymes. Alcohol dehydrogenase subunits are encoded at five different gene loci, and genetic polymorphism occurs at two alcohol dehydrogenase loci. Variant isoenzymes produced at the two polymorphic alcohol dehydrogenase loci account for the differences in enzyme electrophoretic patterns observed among individuals. Some of these variant isoenzymes exhibit widely different kinetic properties, and this may account for the 2- to 3-fold variation in alcohol elimination rate among individuals. Since the protein sequence of several of the alcohol dehydrogenase subunits has been determined and several of the alcohol dehydrogenase genes has been cloned, some of the structural changes which give rise to differences in catalytic and electrophoretic properties are now known. Genetic polymorphism also occurs at the aldehyde dehydrogenase gene locus which encodes the mitochondrial low Km for acetaldehyde aldehyde dehydrogenase isoenzyme. The variant isoenzyme exhibits little or no catalytic activity. Individuals with this "null" variant have higher than normal blood acetaldehyde levels and exhibit an alcohol-flush reaction which appears to be a deterrent to heavy drinking and alcoholism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Strength-Interval Curves for Cardiac Tissue Predicted Using the Bidomain Model

Cardiac Strength-Interval Curves. Introduction : Strength-interval curves are predicted for unipolar anodal and cathodal stimulation of cardiac muscle.
Methods and Results : Cardiac tissue is represented by the bidomain model, and the active properties of the membrane are described by the Beeler-Reuter model. Two successive stimuli (S₁ and S₂) are delivered through a single extracellular electrode. The S₂ threshold is determined as a function of the S₁-S₂ interval, for anodal and cathodal S₂ stimuli with 2-, 5-, 10-, and 20-msec durations. Each of the resulting cathodal and anodal strength-interval curves is divided into two parts: one section corresponding to make stimulation (long intervals) and the other section corresponding to break stimulation (short intervals). Generally, the cathodal strength-interval curves are decreasing functions of interval, except for an anomalous section of the 20-msec duration cathodal curve in the interval range from 310 to 318 msec. At short intervals, the anodal strength-interval curve contains a deep dip, which is more prominent for longer S₂ durations. The cathodal threshold is less than the anodal threshold for all intervals except those corresponding to the end of the refractory period.
Conclusion : The bidomain model predicts complex anodal and cathodal strength-interval curves, with the anodal curve containing a dip (supernormal stimulation). These results resemble the experimental observations of Dekker.     

Role of histamine release in nonspecific vasodilatation during anodal and cathodal iontophoresis

Nonspecific vasodilatation during iontophoresis is an important confounding factor in experimental pharmacology. In this investigation, we studied the involvement of sensory nerves and histamine-related reactions in causing nonspecific vasodilatation in a model of anodal and cathodal iontophoresis of sodium chloride. Firstly, we applied a mixture of local anesthetic (EMLA) cream to confirm its suppressive effect on nonspecific vasodilatation and to measure its efficacy in three different dosages (duration: 1, 2, and 3 h). We then investigated the role of histamine in nonspecific vasodilatation by giving an oral antihistamine drug (cetirizine) to subjects who had and had not been given EMLA. We found substantial suppression of the nonspecific vasodilatation in all EMLA-treated groups (all dosages) compared with untreated controls (with suppression rates of 60-65%). Dosage had no significant effect. A further suppression of nonspecific vasodilatation was seen after oral cetirizine during anodal and cathodal iontophoresis in both EMLA-treated and untreated groups. The antihistamine effect was most pronounced during anodal iontophoresis. These results suggest a histaminergic increase in perfusion that may be independent of neurogenic mechanisms and depend on polarity (anode or cathode). Local nerve blocks (EMLA) together with cetirizine may therefore be used to reduce nonspecific vasodilatation in both anodal and cathodal iontophoresis.     

Identification of blood pressure quantitative trait loci that differentiate two hypertensive strains

OBJECTIVE: To describe genetic loci that differentiate blood pressures in two genetically hypertensive strains, the Dahl salt-sensitive (S) rat and the Albino Surgery (AS) rat. METHODS: A genome scan was performed using 222 genetic markers on an F2 population derived from two hypertensive strains, S and AS. The F2 rats were fed 8% NaCl for 5 weeks before blood pressure measurements were taken. RESULTS: Three blood pressure quantitative trait loci (QTL) were detected, one on each of rat chromosomes (RNO) 2, 4 and 8. The QTL on RNO4, unlike those on RNO2 and RNO8, was not detected in any of the previous seven linkage analyses reported with the S rat as one of the parental strains. Interactions between genetic loci throughout the genome were sought and interactions involving RNO4 with RNO8 and RNO4 with RNO14 were found. Including the new RNO4 locus identified in the present study, 16 distinct regions of the S rat genome have been demonstrated, by linkage analyses, to harbour loci that control blood pressure in the S rat. CONCLUSIONS: Increased blood pressure in two hypertensive strains, S and AS, is differentially regulated by genetic factors present on RNOs 2, 4 and 8. Therefore, of the 16 distinct genomic regions known to harbour blood pressure QTL in S rats, 13 are likely to contain blood pressure alleles that function similarly in the S rat and the AS rat, whereas three regions differentiate the two strains.     

Four peroxidase Loci in red-fruited tomato species: genetics and geographic distribution

The banding patterns of certain anodal peroxidase variants of red-fruited tomato species are governed by alleles at four loci—two alleles per locus. Alleles at three loci code for modified enzyme migration patterns and are codominant in heterozygotes; those at the fourth locus code for presence or absence of a band. No evidence of linkage was detected in preliminary tests between four of the six possible combinations of loci. All variant alleles—i.e., those not represented in the standard genotype of Lycopersicon esculentum—exist in the wild L. pimpinellifolium from coastal Peru; all but Prx-3ⁿ are also known in L. esculentum from the sympatric region but are rare or absent elsewhere. Between the distributions of alleles of Prx-1 and those of Ge, the gamete-eliminator locus, a significant association exists, which probably does not owe to genetic linkage. The tendency of alleles of Prx loci, as well as those of cm, Ge, h, and Od, to be shared between wild and cultivated taxa in the sympatric region but seldom elsewhere, in addition to published correlated evidence, suggests that the wild alleles tend to substitute in cultivated forms as a result of introgression. In respect to the number of common alleles, cultivated tomatoes more closely resemble the wild L. esculentum var. cerasiforme than L. pimpinellifolium.     

Genetic variation at the locus encompassing 11-beta hydroxylase and aldosterone synthase accounts for heritability in cortisol precursor (11-deoxycortisol) urinary metabolite excretion

Genetic variation in the gene encoding aldosterone synthase (CYP11B2) has previously been shown to be associated with hypertension and left ventricular hypertrophy. The intermediate phenotype most consistently associated with variation at this locus is that of elevated plasma 11-deoxycortisol (S). However, in normal subjects, aldosterone synthase does not metabolize S, which is converted to cortisol (F) by the enzyme 11 beta hydroxylase, encoded by the gene CYP11B1, which lies adjacent to CYP11B2 on chromosome 8. It is possible that the quantitative trait locus for the phenotype is within CYP11B1 and that linkage disequilibrium across the extended locus could account for these observations. However, variation across the whole CYP11B1/B2 locus had not been extensively characterized with respect to these phenotypes. We genotyped six polymorphisms in the CYP11B2 gene and three polymorphisms in the CYP11B1 gene in 248 Caucasian nuclear families comprising 1428 individuals. We measured plasma levels of S and F in 460 individuals from 86 families and urinary excretion rates of tetrahydrodeoxycortisol (THS) and tetrahydrodeoxycorticosterone in 573 individuals from 105 families. We examined heritability of the phenotypes and their association with genotypes and haplotypes at this locus. All steroid phenotypes except urinary tetrahydrodeoxycorticosterone were highly heritable (P < 0.00001). There was strong linkage disequilibrium across the CYP11B1/B2 locus. There was modest evidence for association between polymorphisms of CYP11B2 and plasma levels of S (P = 0.02 for T4986C polymorphism) and the plasma S to F ratio, reflecting the activity of 11-beta hydroxylase (P = 0.01 for T4986C polymorphism). There was strong evidence for association between polymorphisms of both CYP11B1 and CYP11B2 and urinary THS, which was strongest for the CYP11B1 exon 1 polymorphism (P = 0.00002). Addition of other marker data to CYP11B1 exon 1 did not improve the fit of a log-linear model. Genotype at CYP11B1 explained approximately 5% of the variance in urinary THS excretion in the population. Thus, it is likely that linkage disequilibrium between causative CYP11B1 variants and CYP11B2 polymorphisms account for the previous observations. Further fine-mapping studies across the CYP11B1 locus are required to localize the causative variant(s) for the biochemical phenotype; this may also identify susceptibility alleles for hypertension and left ventricular hypertrophy.     

Nonsustained Reentry Following Successive Stimulation of Cardiac Tissue Through a Unipolar Electrode

Reentry Following Unipolar Stimulation. Introduction : Using numerical simulations, we predict that nonsustained reentry occurs following a strong, premature stimulus through a unipolar electrode.
Methods and Results : Our simulations were based on the bidomain model of cardiac tissue, and the active membrane properties were represented by the Beeler-Reuter model. An outwardly propagating wavefront was excited by an initial stimulus (SI). A second stimulus (S2) was then applied through the same electrode. Nonsustained reentry or reentrant-like behavior followed the S2 stimulus for both cathodal and anodal stimulation, and were associated with "break" stimulation but not with "make" stimulation. The direction of spiral-wave rotation was reversed when the polarity of the stimulus was reversed. These complex dynamics occur only for a narrow window of S1-S2 intervals. During anodal S2 stimulation, two different modes of reentry exist. Our simulations also explain the "no response" phenomenon.
Conclusion : Our mathematical model predicts that both anodal and cathodal unipolar S2 stimulation results in reentry. This behavior arises from an interaction of virtual anodes and cathodes surrounding the stimulating electrode.     

Development of porcine pancreatic hydrolases and their isoenzymes from the fetal period to adulthood

The appearance and activity of various porcine pancreatic hydrolases were studied during fetal and postnatal development. Quantitatively, the enzyme activities in activated pancreas homogenates were low but increased during the second half of the fetal period, using the substrates Bz-Arg-pNA for measuring anodal and cathodal trypsin, Suc-Phe-pNA (chymotrypsin A and C, and elastase II) and Suc-(Ala)3-pNA (elastase I and protease E). Postnatally, after an initial decrease during the first week, the enzyme activities increased markedly, especially from 10-14 weeks to 6 months. The individual hydrolases were identified after electrophoretic separation in agarose gel and staining with various substrates either directly in the gel or after transfer to nitrocellulose membranes (enzymoblotting). During the fetal period, chymotrypsin A and B, elastase II, carboxypeptidase A, and amylase appeared at approximately 65 days and anodal trypsin, at approximately 76 days. After birth, new proteinases appeared after the first week including chymotrypsin C, cathodal trypsin, and protease E, whereas elastase I was found from 5 weeks after birth. Concomitantly, unidentified "fetal proteinase(s)" with caseinolytic, Ac-Phe-beta NE and CBZ-Ala-beta NE activities began to diminish and disappeared 10-14 weeks after birth. This study showed a marked increase in the overall pancreatic enzyme activities, as well as an age-dependent expression of the variety of pancreatic hydrolases during porcine ontogeny.     

Patterns of Factor-VIII Related Antigen on Crossed Immunoelectrophoresis and Large Pore Polyacrylamide Gel-Crossed Immunoelectrophoresis in von Wilkbrand's Disease

Plasma samples from patients with various types of von Willebrand's disease were subdivided into six patterns according to the electrophoretic mobility and shape of VIIIR: Ag on crossed immunoelectrophoresis (CIE): pattern 1 no precipitation arc, pattern 2 normal mobility with low arc, pattern 3 intermediate mobility with low arc, pattern 4 faster anodal mobility with low arc, pattern 5 normal mobility with normal arc height, pattern 6 faster anodal mobility with normal arc height. Of 62 patients, 14 had pattern 1, 6 pattern 2, 16 pattern 3, 12 pattern 4, 9 pattern 5, and 5 pattern 6.
Large pore polyacrylamide-agarose gel-crossed immunoelectrophoresis (PAAG-CIE) of crude factor VIII fraction from cryoprecipitate revealed no arcs in patients with pattern 1, three arcs of reduced height in the patients with patterns 2 and 3, four arcs very similar to normal control in patients with pattern 5, and two arcs with fast anodal migration in the patients with patterns 4 and 6. Crude factor VIII fractions from normal cryosupernatant showed one low fast anodally migrating arc corresponding to the fourth arc of normal cryoprecipitate. No peak was seen in patients with pattern 1, and one low fast anodal arc similar to normal control was present in the patients with patterns 2, 3, 4, 5 and 6.     

Some factors affecting bubble formation with catheter-mediated defibrillator pulses

Factors affecting bubble formation during delivery of defibrillator pulses to arrhythmogenic cardiac tissue via a catheter are unknown. We investigated the role of energy, electrode surface area, interelectrode distance, and electrode polarity on bubble formation and on current and voltage waveforms during delivery of damped sinusoidal discharges from a standard defibrillator to anticoagulated bovine blood. Gas composition was studied with mass spectrometry. Defibrillator energy settings were varied between 5 and 360 J. The principal catheter used for study was a Medtronic 6992A lead. Additional electrodes tested included 2, 5, and 10 mm long No. 6F, 7F, and 8F copper electrodes. Interelectrode distances used to assess the effect of anode-cathode spacing were 1, 5, 10, and 20 cm. Bubble volume increased linearly from 0.043 to 0.134 ml per cathodal pulse and from 0.030 to 3.50 ml per anodal pulse as energy settings were increased from 5 to 360 J (r = .99). Typical smooth waveforms for both current and voltage were seen only in the absence of bubbles. The voltage waveform was distorted for each cathodal pulse of 100 J or more and for each anodal pulse of 10 J or more only if bubbles were present. The effect of electrode surface area on bubble formation was tested at a 200 J energy setting and at a 10 cm interelectrode distance with the use of cathodal pulses. Bubble formation varied inversely with electrode surface area (r = .876). Bubble formation, however, varied minimally as interelectrode spacing was changed from 1 to 20 cm. The effect of polarity on bubble formation when the Medtronic 6992A distal electrode and an 8.5 cm disk electrode separated by 10 cm were used was highly significant. For a 200 J pulse, bubble formation with the catheter as anode was 3.30 +/- 0.10 ml and with the catheter as cathode it was 0.070 +/- 0.002 ml (p less than .001). Mass spectrometry of both anodal and cathodal gas samples demonstrated the constituents of the gas bubble to include a variety of gases, which is inconsistent with simple electrolytic production of the bubbles observed. The predominance of nitrogen in either polarity sample suggested that the principal source of the bubble was dissolved air. In summary, bubble formation at an electrode receiving damped sinusoidal outputs from a standard defibrillator does not vary significantly with varying interelectrode distance. However, it is directly proportional to energy and inversely proportional to electrode surface area. Anodal catheter discharges produce considerably more bubbles than do cathodal discharges.(ABSTRACT TRUNCATED AT 400 WORDS)