Showing papers by "University of Cologne published in 1982"
TL;DR: The clinical results can be explained by the improvement in various indices of humoral and cellular immunocompetence and the protein status in the PPN group and their deterioration in the control group during the preoperative course.
421 citations
266 citations
TL;DR: Observations account for the role of endonuclease VII in the DNA metabolism of phage T4, and provide the first example of an enzyme that acts specifically on branch points in duplex DNA.
259 citations
TL;DR: In this article, the authors show that the relative abundances of orthopyroxene and olivines are significantly lower in LREE than in HREE, while clinopyroxenes are similar in absolute chondrite-normalized concentrations to those known from other studies.
158 citations
TL;DR: Magnetic neutron spectra as a function of temperature are presented for the intermediate-valence compounds Ce${\mathrm{Pd}}_{3}, Ce${Sn}}_{ 3}, and TmSe, with an overall width of about 7 to 30 meV as mentioned in this paper.
Abstract: Magnetic neutron spectra as a function of temperature are presented for the intermediate-valence compounds Ce${\mathrm{Pd}}_{3}$, Ce${\mathrm{Sn}}_{3}$, Ce${\mathrm{Be}}_{13}$, Yb${\mathrm{Cu}}_{2}$${\mathrm{Si}}_{2}$, and TmSe. All compounds show the normal local 4$f$ form factor but a broadened magnetic energy spectrum with an overall width of about 7 to 30 meV and with very little temperature dependence (except TmSe). Closer analysis reveals a residual crystal-field spectrum in Yb${\mathrm{Cu}}_{2}$${\mathrm{Si}}_{2}$ which may also underlie the spectra of the other compounds. A detailed description of the data analysis is given.
157 citations
TL;DR: In this article, the longwave and shortwave radiative components of the cloud layer energy budget were measured and good agreement was obtained between the observations and several radiation schemes and in particular the measured cloud shortwave absorption was close to the theoretical values.
Abstract: Observations of marine stratocumulus obtained by three research aircraft during the JASIN experiment are presented. Detailed measurements were made of the thermodynamic, cloud physics and radiation fields. These showed an essentially well-mixed boundary layer with cloud liquid water contents close to their adiabatic values. The mean drop radius increased steadily towards cloud top, where evidence of inhomogeneous mixing was found. Both the longwave and shortwave radiative components of the cloud layer energy budget were measured. Good agreement was obtained between the observations and several radiation schemes and in particular the measured cloud shortwave absorption was close to the theoretical values. At midday, the net longwave cooling of the cloud layer was found to be approximately compensated by the shortwave warming, although the regions of net warming and cooling were separated vertically, thereby promoting convection within the cloud. The wider implications of these results to studies of stratiform cloud are discussed.
140 citations
TL;DR: By RNA blot analysis, it is shown that the cloned cDNAs for mouse alpha-casein, beta-casesin, gamma- casein and epsilon-case in and the acidic whey protein cross-hybridize with mRNAs of the rat, demonstrating partial sequence homology between the corresponding mRN as of those species.
Abstract: We have characterized and cloned the lactation-specific mRNAs of mouse mammary glands. The group of eight milk-protein-specific mRNAs were identified (a) by size and antigenic properties of their translation products in vitro and (b) by characterization of their respective cDNA clones.
Two α-caseins (43 kDa and 39 kDa) are encoded by mRNAs of 1600 nucleotides and two β-caseins (26 kDa) are encoded by mRNAs of 1450 nucleotides in length. Three smaller caseins, γ-casein (23.7 kDa), δcasein (21 kDa) and £-casein (14.5 kDa) are synthesized by mRNAs of 880, 1150 and 860 nucleotides. Beside these casein mRNAs a mammary specific 620 nucleotide mRNA codes for a novel acidic whey protein (13.7 kDa).
cDNA clones corresponding to the mRNAs for the lactation-specific proteins have been isolated from a mammary-specific cDNA library. Cloned α-casein cDNA hybridizes to both β-casein specific mRNAs and cloned β-casein cDNAs hybridize with both β-casein specific mRNAs. By RNA blot analysis we show that the cloned β -casein cDNAs for mouse α-casein, β-casein, γ-casein and &-casein and the acidic whey protein cross-hybridize with mRNAs of the rat, demonstrating partial sequence homology between the corresponding mRNAs of those species.
128 citations
TL;DR: In this paper, the authors derived the imaginary part of the dielectric function in the wave-number range from 3 to 150 for cubic BaTi material and applied the fluctuation-dissipation theorem.
Abstract: Hyper-Raman scattering from cubic BaTi${\mathrm{O}}_{3}$ is studied to clarify the controversies about the low-frequency dielectric response in this material. Applying the fluctuation-dissipation theorem, we obtain the imaginary part ${\ensuremath{\epsilon}}^{\ensuremath{'}\ensuremath{'}}(\ensuremath{\Omega})$ of the dielectric function in the wave-number range from 3 to 150 ${\mathrm{cm}}^{\ensuremath{-}1}$. ${\ensuremath{\epsilon}}^{\ensuremath{'}\ensuremath{'}}(\ensuremath{\Omega})$ can be adequately described by a classical single-oscillator dispersion formula. In approaching the Curie temperature, we find a continuous decrease of the mode frequency ${\ensuremath{\Omega}}_{0}$. The relative damping constant $\frac{\ensuremath{\gamma}}{{\ensuremath{\Omega}}_{0}}$ exceeds 2, so that the mode may be referred to as intermediate between oscillator and relaxator. Because of the high damping ${\ensuremath{\epsilon}}^{\ensuremath{'}\ensuremath{'}}(\ensuremath{\Omega})$ can be formally written as the sum of two overdamped oscillator contributions. This would lead to the concept of a soft-mode saturation and an extra dispersion mechanism as has been recently inferred from the far-infrared reflectivity spectrum. However, we do not find any evidence for this mode splitting and, so far, regard it as artificial.
119 citations
TL;DR: The nucleotide sequence of two λ 1 gene from hybridomas and a λ 2 gene from a myeloma are determined to demonstrate that somatic mutation in λ genes can occur in both the framework and CDR residues.
Abstract: Studies of the murine λ1 light chains produced by myeloma cells provided the first evidence for somatic point mutation of germ-line variable (V) region genes. An examination of the variable regions of 19 λ1 chains revealed seven which differed from a common sequence by one to three amino acid substitutions1. Subsequently, one of these presumed somatic variants of the single λ1 V gene was characterized by DNA sequence analysis of the rearranged functional gene2. The predicted DNA sequence alteration was observed and no silent mutation was evident. These studies of λ chain variants suggested that the hypervariable, complementarity-determining regions (CDRs) ht be a preferred site of somatic mutation because all seven characterized variants contained substitutions only in these regions. By contrast, comparisons of closely related κ chain variable region amino acid sequences, and more recently Vκ and VH genes8–12, have suggested that somatic mutation probably occurs in codons for both framework and CDR residues. To examine this apparent discrepancy between the sites of somatic mutation in λ and κ genes, we have determined the nucleotide sequence of two λ 1 gene from hybridomas and a λ 2 gene from a myeloma. These sequences demonstrate that somatic mutation in λ genes can occur in both the framework and CDR residues.
116 citations
TL;DR: In this article, the lower and upper critical fields of the system of heavy fermions were measured and the observed, extremely high values of the slope of the slopes were used to support the formation of Cooper pairs.
Abstract: Measurements are reported of the lower and upper critical fields, ${B}_{c1}(T)$ and ${B}_{c2}(T)$, of Ce${\mathrm{Cu}}_{2}$${\mathrm{Si}}_{2}$. The observed, extremely high values of the slope ${(\ensuremath{-}\frac{d{B}_{c2}}{\mathrm{dT}})}_{{T}_{c0}}$ lend strong support to the formation of Cooper pairs by the heavy fermions which exist in the normal state of Ce${\mathrm{Cu}}_{2}$${\mathrm{Si}}_{2}$. Characteristic parameters of the system of heavy fermions are derived.
112 citations
TL;DR: In this paper, the γ-ray spectrum emitted after thermal neutron capture in 35Cl has been studied by use of the crystal and pair spectrometers installed at the ILL high flux reactor.
TL;DR: It was noted that small doses of a monoclonal NP-specific IgM antibody failed to enhance the response to NP-SRC, and that the role of the variable region in feedback inhibition is sufficiently explained by its affinity for the antigen.
TL;DR: One cDNA clone of an HLA class I gene, pHLA-1, in combination with γ-ray-induced HLA loss variants, will be used to identify recombinant DNA HLA clones and to correlate individual DNA restriction fragments with expression of specific HLA alleles.
Abstract: Class I loci of the human major histocompatibility complex (MHC) encode 44,000-molecular weight polypeptides that associate nonconvalently with β-microglobulin1. Included in this category are the HLA-A, -B and -C loci (Fig. 1a), which are extensively polymorphic2. HLA-specific cDNA clones3,4 now allow this polymorphism to be studied at the DNA level. However, the lack of sufficient amino acid sequence data for all but a few of the class 1 antigens presents a major difficulty in the allelic assignment of those DNA clones obtained in man3–5 and mouse6–8. HLA loss variants produced with deletion-inducing ionizing radiation offer a means of partially circumventing the time-consuming and difficult task of sequencing HLA class I gene products for identifying restriction enzyme digest fragments of DNA and recombinant DNA clones. P.K. et al.9 used γ-ray irradiation followed by immunoselection to obtain many mutants that no longer expressed one or more HLA specificities from the human lymphoblastoid cell line LCL 721. Only the expression of HLA-B8 was lost in one class of mutant, while expressions of HLA-B8 and at least one additional cis- linked HLA allele were lost in mutants of the second class. Some mutants lost expression of the entire haplotype, that is, HLA-A1, -B8 and -DR3 (ref. 9) as well as SB (refs 4, 10 and unpublished results). Recently, anti-HLA-B5 and anti-HLA-A2 sera have been used to isolate mutants that have lost expressions of one or more loci of the haplotype on the other chromosome 6 of LCL 721 (Table 1)10. Data presented here illustrate how one cDNA clone of an HLA class I gene, pHLA-1, in combination with γ-ray-induced HLA loss variants, will be used to identify recombinant DNA HLA clones and to correlate individual DNA restriction fragments with expression of specific HLA alleles.
TL;DR: Blood, saliva and urine were collected for assay of oxcarb, 10,11-dihydro-10-hydroxy-carbamazepine (OHcarb), and 10, 11-dhydrotrans-10,11 -dihydenroxy- carbamazepines (diol), and only 25% of OHcarb was conjugated and diol was unconjugated.
Abstract: Oxcarbazepine (oxcarb) 600 and 900 mg (2360 and 3540 mumol) was taken by 3 volunteers (2 female, 1 male; 45-67 kg; age 22-34 years) after an overnight fast. Blood, saliva and urine were collected for the next 72 h for assay of oxcarb, 10,11-dihydro-10-hydroxy-carbamazepine (OHcarb), and 10,11-dihydro-trans-10,11-dihydroxy-carbamazepine (diol). Oxcarb reached a maximum level of about 1 microgram/ml (3.93 mumol/l) within 1 h and dropped below the detection limit (0.1 microgram/ml = 0.39 mumol/l) within 3 h. The active metabolite OHcarb appeared in the blood before oxcarb and reached the higher maximum level of 7.4 microgram/ml (29 mumol/l) after 7 h. Thereafter serum levels decreased with a t1/2 of about 25 h, and after 40 h with a t1/2 of 9 h, the latter agreeing with the renal excretory t1/2 calculated from the urine data (10 h). The ratio of OHcarb concentration in saliva to that in plasma varied considerably (0.3-1.7; median 1; r greater than 0.9), whereas that of blood to plasma was 1.25 with only small variation (r greater than 0.98); OHcarb concentrations in erythrocytes were 50% higher than in plasma. Diol was detected in blood (maximum level 0.5 microgram/ml = 1.84 mumol/l) in 2 volunteers. 45% of the dose could be recovered in urine (Oxcarb 5%, OH-carb 36%, Diol 4%). Whereas Oxcarb was completely conjugated, only 25% of OHcarb was conjugated and diol was unconjugated.
TL;DR: In an attempt to isolate the transposable genetic element Ds from Zea mays L., cloned DNA fragments hybridizing to a cDNA clone derived from the sucrose synthase gene in a λ vector showed that no part of this DNA is deleted.
Abstract: In an attempt to isolate the transposable genetic element Ds from Zea mays L, we cloned DNA fragments hybridizing to a cDNA clone derived from the sucrose synthase gene in a lambda vector (lambda::Zm Sh) The fragments cloned from wild-type and from the Ds-induced mutant sh-m5933 (lambda::Zm sh-m5933) share a segment 6 kb long while a contiguous segment of 15 kb of lambda::Zm sh-m5933 (mutant-derived DNA) does not hybridize to the DNA segment cloned from the wild-type Restriction maps are given, and the junction point between the two DNA segments in the mutant clone was determined Hybridization of DNA fragments, present in the wild-type DNA of lambda::Zm Sh, but not in the mutant clone, lambda::Zm sh-m5933, to genomic DNA of sh-m5933 showed that no part of this DNA is deleted It cannot be said whether the DNA found in the mutant, but not in the wild-type clone, has been brought there by Ds insertion or by another Ds-dependent DNA rearrangement The mutant-derived DNA was hybridized to genomic DNA of various maize lines digested by several restriction endonucleases Approximately 40 bands were detected The mutant-derived DNA contains two pairs of inverted repeats several hundred nucleotide pairs long, one of which is located at the junction to wild-type-derived DNA
TL;DR: In this article, the interconfigurational mixing and excitation energies of the Eu ions were determined experimentally as functions of pressure and temperature in terms of mixing, elastic, and conduction-electron energies.
Abstract: The interconfigurational mixing and excitation energies, $\ensuremath{\Gamma}$ and ${E}_{x}$, of the Eu ions in ${\mathrm{EuCu}}_{2}$${\mathrm{Si}}_{2}$ are determined experimentally as functions of pressure and temperature. $\ensuremath{\Gamma}$ seems to depend only on ${E}_{x}$, and the strongly nonlinear $\ensuremath{\Gamma}({E}_{x})$ reflects the intra-ionic multiplet splittings and degeneracies of $4{f}^{6}$. The observed pressure and temperature dependence of ${E}_{x}$ is analyzed self-consistently in terms of contributions from mixing, elastic, and conduction-electron energies, which arise from the temperature and pressure dependence of the valence.
TL;DR: The genetic analysis provides strong evidence that the strain specificity of the idiotope repertoire is a result of V region polymorphism in the mouse.
Abstract: In the present analysis we dissect the idiotype repertoire, independently of hapten-binding specificity, by immunizing different strains of mice with cross-linked monoclonal anti-idiotope antibodies against antibody B1-8. B1-8 is a monoclonal antibody with specificity for the hapten (4-hydroxy-3-nitro-phenyl)acetyl (NP) and carries a germ line gene-encoded variable region. The results demonstrate that the expression of B1-8 idiotopes and their association with each other and with NP-binding specificity are strain-specific. Certain idiotopes are expressed on antibodies differing in antigen-binding specificity, whereas one of the idiotopes appears strictly associated with NP-binding antibodies. The genetic analysis provides strong evidence that the strain specificity of the idiotope repertoire is a result of V region polymorphism in the mouse.
TL;DR: The amino acid sequence of the N-terminal tryptic glycopeptide from a minor human erythrocyte membrane sialoglycoprotein (component D or glycophorin C) was determined by manual sequencing, and a part of its structure shows a striking similarity to the sequence of a certain region of the MN and Ss ery throat membrane sIALoglycoproteins (glycophorins A and B), suggesting that the molecules might be related.
Abstract: The amino acid sequence of the N-terminal tryptic glycopeptide from a minor human erythrocyte membrane sialoglycoprotein (component D or glycophorin C) was determined by manual sequencing. The glycosylation sites were identified by a new procedure for the detection of the glycosylated derivatives released by Ednian degradation. The fragment, comprising 47 residues, was found to contain an average of about 12 0-glycosidically linked oligosaccharides and one asparagine-linked carbohydrate chain. An identical hexapeptide sequence occurring in two regions of the glycopeptide provides evidence that it has developed by an internal gene duplica- tion during evolution. In addition, a part of its structure shows a striking similarity to the sequence of a certain region of the MN and Ss erythrocyte membrane sialoglycoproteins (glycophorins A and B), suggesting that the molecules might be related.
TL;DR: The undermethylation of integrated adenovirus genes in tumor and transformed cells appeared to be a necessary but not a sufficient precondition for the expression of these genes.
TL;DR: Comparison of the glycosyl acceptor properties of the linear peptides and their corresponding cyclic analogues allows the following statements to be made about the possible structural features for N-glycosylation.
Abstract: Conformational aspects of N-glycosylation of glycoproteins have been studied by using a series of peptides which contained, in addition to the `marker sequence' Asn-Gly-Thr, two cysteine residues in various positions of the peptide chain. The presence of two cysteines permitted a partial fixation of the above triplet sequence in cyclic structures of various size by intramolecular disulphide bond formation. Comparison of the glycosyl acceptor properties of the linear peptides and their corresponding cyclic analogues allows the following statements. The considerably lower acceptor capabilities of the cyclic derivatives indicate that the restriction of rotational degrees of freedom imposed by disulphide bonding results in a conformation which hinders a favourable interaction of the peptide substrate with the N-glycosyltransferase. On the other hand, the glycosylation rate of linear peptides increases with increasing chain length, suggesting that the amino acids on both the N- and C-terminal side of the markersequence'maycontribute→aconsrab≤extent→the∈ductionofanmarkersequence′maycontribute→aconsrab≤extent→the∈ductionofanactive' conformation. Realization of a potential sugar attachment site requires a hydrogen bond interaction within the `marker sequence' between the oxygen of threonine (serine) as the hydrogen bond acceptor and the β-amide of asparagine as the donor [Bause & Legler (1981) Biochem. J. 195, 639–644]. This interaction is obviously facilitated when the peptide chain can adopt a conformation which resembles a β-turn or other loop structure. The available experimental and statistical data are discussed in terms of possible structural features for N-glycosylation, with the aid of space-filling models.
TL;DR: In this article, the transfer of radiative energy in model atmospheres can now be calculated with high economy and sufficient accuracy based on the methodology of a two-stream approximation (Kerschgens et al. 1978).
Abstract: Based on the methodology of a two-stream approximation (Kerschgens et al. 1978) the transfer of radiative energy in model atmospheres can now be calculated with high economy and sufficient accuracy. In this model the number of spectral intervals has been minimized to four (solar spectrum) and six (infrared spectrum) for which new effective transmission functions have been computed, where standard aerosol profiles and absorption and scattering coefficients are incorporated. The concentrations of major atmospheric gases (water vapour, carbon dioxide, ozone), the cloud cover and cloud liquid water content of each layer can be changed freely. Thus this model could be used in any numerical circulation model.
In the first part of this paper we discuss the basic principles of the method and results obtained for cloudless model atmospheres. The accuracy of computed flux densities is better than 5% and of flux divergences better than 20% in the worst cases.
In the second part this method will be applied to total and partial cloud cover in each layer.
TL;DR: It is shown that alkyl radical species present in CH4 or iso-C4H10 plasma can react with substrate molecules to give [M+CnH2n] species which may be mistaken for a series of homologous compounds present in the sample.
Abstract: It is shown that alkyl radical species present in CH4 or iso-C4H10 plasma can react with substrate molecules to give [M+CnH2n] species. These species become evident especially in negative chemical ionization as [M+CnH2n]−˙ and, less obviously, in positive chemical ionization as [M+CnH2n+1]+ ions which, for example in natural products chemistry, may be mistaken for a series of homologous compounds present in the sample.
TL;DR: Cloned DNA containing 22.2 kb of the chicken lysozyme gene region was screened with use of a nitrocellulose filter binding technique for specific recognition by nuclear DNA binding proteins from chicken oviduct cells, indicating that only one class of proteins is involved in the recognition of all four sites.
TL;DR: In the Alpine foothills, stratigraphically useful indicators of warm climates are missing, but analogies in terrace development permit comparison with the Lower Rhine and Danube.
TL;DR: Pyruvate supports C2H2 reduction by isolated heterocysts, however, with lower activity than Na2S2O4 and H2, confirming that the organism has an incomplete tricarboxylic acid cycle.
TL;DR: In this article, the relativistic corrections to the Newtonian tidal acceleration generated by a rotating system are studied, and the possibility of testing the theory of gravitation by measuring such effects in a laboratory in orbit around the Earth is considered.
Abstract: The relativistic corrections to the Newtonian tidal accelerations generated by a rotating system are studied. The possibility of testing the relativistic theory of gravitation by measuring such effects in a laboratory in orbit around the Earth is considered. A recent proposal to measure a rotation-dependent tidal acceleration as an alternative to the Stanford gyroscope experiment is critically examined and it is shown that such an experiment does not circumvent the basic difficulties associated with the gyroscope experiment.
TL;DR: Protein preparations from cotyledons of red radish catalyzed the the formation of depsides between cinnamic acids and L-malate, using 1-O-acyl glucose conjugates as the donors, showing an absolute acceptor specificity towards L- malate and a pronounced donor specificity with 1-sinapoylglucose.
Abstract: Protein preparations from cotyledons of red radish (Raphanus sativus L. var. sativus) catalyzed the the formation of depsides between cinnamic acids and L-malate, using 1-O-acyl glucose conjugates as the donors. This activity showed an absolute acceptor specificity towards L-malate and a pronounced donor specificity with 1-sinapoylglucose (1-O-sinapoyl-β-D-glucose). Maximal rate of sinapoyl-L-malate formation was found to be at pH 6.3, and there was no requirement for metal ions or sulfhydryl group reagents. The K
m values were found to be 0.46 mM for 1-sinapoylglucose and 54 mM for L-malate. Protein extracts obtained from seedlings at different stages of seedling development did not significantly differ with respect to the properties of the enzymatic activity. Appearance and development of extractable activities correlated well with the in vivo transacylation kinetics of 1-sinapoylglucose to sinapoyl-L-malate during seedling growth. Maximal activity was extracted from 10–14-d-old seedlings and found to be at 67 pkat pair-1 of cotyledons. This new enzymatic activity in phenylpropanoid metabolism refers to an enzyme which can be classified as 1-sinapoylglucose: L-malate sinapoyltransferase (SMT) (EC 2.3.1.-).
TL;DR: The analysis of IgCn-gene arrangement in myeloma and hybridoma cells has shown that on the active chromosome all IgCH genes located in the germ line 5' to the expressed one are deleted, which allows two interpretations: either switch recombination is a highly specific process based on the induction of switch site-specific proteins; or it is simply due to a general recombinatorial process.
Abstract: Since its discovery in 1964 (Nossal et al. 1964) immunoglobulin (Ig) class switching in B lymphocytes has attracted the attention of molecular biologists because it represents an example of sequential use of members of a gene family in a cell lineage, in the course of differentiation. The analysis of IgCn-gene arrangement in myeloma and hybridoma cells has shown that on the active chromosome (defined by an expressed rearranged VHDJH gene) all IgCH genes located in the germ line 5' to the expressed one are deleted (Honjo & Kataoka 1978, Rabbitts et al. 1980, Hurwitz et al. 1980, Cpry et al, 1980, Davis et al. 1980a, Maki et al, 1980). The deleting mechanism apparently makes use of characteristic DNA sequences, called switch regions. Switch sequences are found upstream of al! CH genes and consist of highly repetitive sequences with a high degree of homology from one switch region to the other (Davis et al. 1980b, Kataoka et al. 1980, Kataoka et al. 1981, Marcuet al. 1980, Lang etal. 1982, Sakano et al. 1980). The end points of the deletions which could be identified in myeloma and hybridoma cells and which presumably had happened in the precursors of these cells in the mouse were without exception located within switch regions (Davis et al, 1980a, 1980b, Sakano et al. 1980, Obata et al. 1981). This finding allows two interpretations: either switch recombination is a highly specific process based on the induction of switch site-specific proteins; or it is simply due to a general recombinatorial
01 Jun 1982-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: Stick insects (Carausius morosus) walking on a wheel were perturbed by restricting the forward protraction of individual legs by placing a barrier before a single middle or rear leg, demonstrating a strong, centrally mediated inhibition.
Abstract: Stick insects (Carausius morosus) walking on a wheel were perturbed by restricting the forward protraction of individual legs. A barrier placed before a single middle or rear leg prevented that leg from reaching its normal protraction endpoint but allowed it unimpeded retraction. Upon striking the barrier, the protracting leg attempted to get past it and thereby prolonged protraction. This prolongation increased with the extent to which the obstruction infringed upon the leg's normal step range. Barriers placed near the midpoint of this range elicited large perturbations: the blocked leg often continued its protraction throughout many step cycles of the other legs (Fig. 1 E, F). For the most part walking was irregular and smooth forward progression was disrupted. Nevertheless, the infrequent steps by the affected leg usually were coordinated with those of the adjacent ipsilateral legs. More rostral barrier positions elicited smaller perturbations: the blocked leg usually made one step in each step cycle of the other legs (Fig. 1 B, C, D, G). Measurements for these regular step sequences showed quantitatively that protraction duration increased in proportion to the severity of the infringement on normal leg movement (Figs. 3, 4). The fraction of the step period occupied by protraction increased from ca. 10% for normal walking to ca. 50% for caudal barrier positions. This proportionality is interpreted to show the importance of spatial components of the walking program. When one leg was obstructed, its extended protraction influenced the stepping of the three adjacent legs as follows. First, the ipsilateral rostral leg showed the largest change: its protraction onset was regularly delayed for the duration of the extended protraction (Figs. 4, 7, 8), demonstrating a strong, centrally mediated inhibition. The presence of a further delay of up to 100 to 140 ms suggests that peripheral input from the protracting leg may be important for releasing this inhibition. Second, steps by an adjacent caudal leg were not measurably affected. However, the method may not have sufficed to reveal such effects because during regular walking middle leg protractions rarely lasted long enough to conflict with subsequent steps by the ipsilateral rear leg. Third, contralateral effects differed between middle and rear leg obstructions. If the obstructed leg was a middle leg, its extended protraction had little effect upon stepping by the contralateral middle leg: the latter leg frequently protracted while the blocked leg continued its protraction and there was no consistent change in the phase relation of these two legs (Table 1). In contrast, if the obstructed leg was a rear leg, protractions by the contralateral rear leg tended to be delayed (Table 1).
TL;DR: The signal averaging technique has been applied to improve the signal to noise ratio in highly amplified EKG registrations to help identify patients at high risk of sudden cardiac death.
Abstract: Summary: Since 1963 the signal averaging technique has been applied to improve the signal to noise ratio in highly amplified EKG registrations. Based on the experiences from the literature and the authors own laboratory, the applications of the signal averaging technique in clinical cardiology are reviewed: extraction and analysis of the fetal EKG and P-wave variations, His bundle electro-grams from the body surface (recovery rate 33–100% of cases), ventricular delayed depolarizations within the ST segment of the surface EKG (recovery rate, 40–90% of cases, depending on patient groups investigated), preatrial activity (sinus nodal potentials) from intra-cardiac (recovery rate, 80–90% of individuals), or surface EKGs (recovery rate, 60% of patients), analysis of frequency components of surface EKG-QRS complexes in patients with previous myocardial infarctions, and detection of low amplitude diastolic signals from surface phonocardiogram (recovery rate, 80% of cases). At present, advantages and limitations of the signal averaging technique may be appraised as follows: (1) sinus nodal potentials: S-A conduction times may be more reliable than those obtained by the extra-stimulus technique, since with averaging they are recorded during undisturbed sinus rhythm; direct recordings of changing S-A blocks may be impossible due to the summation process; validation of sinus nodal potentials in man necessary, (2) A-V nodal potentials: demonstration of true A-V nodal rhythm rather than His bundle rhythm; possibly direct identification of abnormal pathways in A-V nodal tachycardias; direct recordings of single A-V nodal blocks impossible due to summation process; (3) surface His bundle potentials: follow-up or screening of patients with A-V nodal and particularly His-Pur-kinje-system blocks; monitoring of antiarrhythmic drug therapy; atrial overlap in one-third of cases; direct identification of higher degree A-V nodal blocks impossible due to summation process (future developments may overcome this problem); (4) ventricular delayed depolarizations: possible identification of patients at high risk of sudden cardiac death; follow-up of therapeutic measures like antiarrhythmic drug therapy or cardiac surgery (bypass grafting, aneurysmectomy); validation of delayed depolarizations from body surface by direct intracardiac and/or epicardial mapping necessary.