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At least 703 records · Page 39Linked to original sources
PubMed1979

[The direct detection of sinus nodal potentials in man by means of the signal-averaging technique (author's transl)].

In 13 patients in the age range of 34 to 70 years (mean: 53 +/- 10 years), during diagnostic His-bundle investigations, registrations from the sinus nodal area were analyzed with a signal-averaging computer. In 12 patients we were able to get reproducible per-P-potentials with a sino-atrial conduction interval between 56 and 227 ms. The normal sequence of the excitation process from the atrium to the AV node together with the bundle of His and to the ventricles in all patients, and the reproducibility of the signal-averaged pre-P-potentials, which were well outlined from the atrial potential with a reasonable conduction interval, suggest that these signal-averaged pre-P-potentials reflect the sinus nodal activity rather than an ectopic focus. In 5 of 11 comparable cases there was a good correlation between the signal-averaged sino-atrial conduction intervals and those calculated with the extrastimulus technique. In 2 patients this correlation was moderate. The signal-averaging process may be impaired by coarse random noise, frequent atrial or ventricular extrasystoles, and by fluctuations of the baseline of the sinus nodal lead. The fact that the registrations are performed during normal undisturbed sinus rhythm offers a considerable advantage over the extrastimulus technique.

Action Potentials↗
PubMedDate not supplied

Direct detection of idiotypic determinants on blotted monoclonal antibodies.

The protein-blotting technique has been tested as a mean to study the expression of idiotypic determinants. A monoclonal BALB/c antipoly (Glu60-Ala30-Tyr10) GAT antibody (G5) was caused to migrate on SDS gel and transferred to a nitrocellulose filter. To facilitate the renaturation of the idiotypic determinants, the blotted proteins were incubated in NP40 buffer, immediately after the transfer. The ability of two anti-idiotypic sera to detect two defined idiotypic specificities of the blotted G5 molecules was investigated. When G5 was electrophoresed on SDS gel under non-reducing conditions, a specific detection of two idiotypic specificities of the G5-blotted molecules was obtained. On the other hand, when G5 was migrated under reducing conditions, none of the two antiidiotypic sera gave a staining of the heavy and the light chains. This result indicates that molecules expressing conformational idiotypic determinants can be detected by protein-blotting technique after migration on SDS gel. Moreover, this suggests the possible interest of this technique to analyse non-antibody molecules bearing idiotypic determinants.

Animals↗
PubMed1995

[Direct detection of loci with pathologic trinucleotide repeats in diseases with anticipation].

We describe a simple method for the identification of pathologically expanded (CCG)n and (CTG)n three nucleotides repeat arrays in the human genome and for the recovery of flanking sequences. We were able to detect the presence of novel high-molecular-weight alleles in at least two of three subjects known to have expanded (CCG)n tracts at the FRAXA locus. The above method may be used for testing of small families or even single affected individuals with disease thought to display clinical evidence of anticipation. The (CCG)n > 200 and (CTG)n > 250 probes may also be useful for individual "DNA fingerprint" identifications.

Alleles↗
PubMed1995

[Direct detection of Toxoplasma gondii with polymerase chain reaction in diagnosis of fetal toxoplasma infection].

Primary infection with Toxoplasma gondii during pregnancy may affect the fetus and result in congenital toxoplasmosis. In Austria serological screening for detection of newly acquired infection during pregnancy was introduced in 1975. In this study we used polymerase chain reaction (PCR) for detection of fetal infection with Toxoplasma gondii. Amniotic fluid samples were analyzed from 11 women with serological indication of acute toxoplasmosis infection. Nine of these women had already received treatment prior to amnio-centesis and no evidence of Toxoplasma gondii DNA was detected with PCR in the respective amniotic fluid samples. Isolation of the organism by mouse inoculation was negative in these cases and follow-up serology as well as clinical examination of the infants confirmed these results. In 2 patients investigation of the amniotic fluid samples by means of PCR was positive; both women had not yet been treated at the time of amniocentesis. Our results indicate that identification of Toxoplasma gondii in amniotic fluid is a useful procedure for diagnosing or excluding fetal infection. Moreover, the current recommendations of the screening program appear to be successful in preventing congenital toxoplasmosis.

Amniotic Fluid↗
PubMed1994

Direct detection of a common inversion mutation in the genetic diagnosis of severe hemophilia A.

Two recent reports suggest that approximately 50% of the cases of severe hemophilia A (factor VIII:C < 0.01 U/mL) may be caused by a gross rearrangement of the factor VIII gene. The mutation involves genomic sequence from exon 1 to within intron 22 of the gene in an inversion event. This rearrangement can be detected on a Southern blot using a probe that is complementary to sequence from within intron 22. In this report, we describe the analysis of 71 severe hemophilia A patients for the presence of this mutation. Thirty-two of the patients (45%) showed evidence of the rearrangement, a figure that confirms the initial reports on 28 patients. Five different patterns of rearrangement have been noted, although two of these patterns (pattern 1 [70%] and pattern 2 [16%]) account for the majority of cases. The other patterns of rearrangement appear to be confined to individual families and may represent the result of additional sequence variation within the region of the genome to which the proximal 22 exons of factor VIII are translocated. Analysis of this patient population for the factor VIII inversion mutation has been extremely useful in a molecular diagnostic sense. In 23 of the cases studied (72%), the affected individual was the only documented hemophiliac in the family and, thus, previous linkage analysis had been limited to the provision of exclusion testing only. In conclusion, it appears that testing for the factor VIII inversion mutation will be positive in approximately 45% of severe hemophiliacs and as such should constitute the initial stage in the genetic testing protocol for these patients' families.

Chromosome Inversion↗
PubMed1994

Antioxidant effects of aqueous garlic extract. 1st communication: Direct detection using the photochemiluminescence.

The antioxidant effect of the aqueous extract from the garlic preparation Kwai was investigated using the method of photochemiluminescence. The method is based on the photo-induced, superoxide radical mediated autoxidation of luminol, and allows for the capability of substances to inhibit the free radical processes in this test system to be quantified, and hence for their antioxidant properties in respect of a standard substance (e.g. ascorbic acid, alpha-tocopherol) to be compared. The aqueous extract obtained from 1 mg of the garlic preparation was found to be anti-oxidatively as effective as 30 nmol of ascorbic acid and/or 3.6 nmol of alpha-tocopherol.

Antioxidants↗
PubMed1993

An integrated procedure for the direct detection of characteristic lipids in tuberculosis patients.

An integrated method is described for the sensitive detection of tuberculostearic, mycocerosic and mycolic acids in infected materials from tuberculosis patients. Tuberculostearic acid is analysed by two-dimensional gas chromatography of pentafluorobenzyl esters, the key component being switched from a short non-polar column to a high resolution polar column with final electron capture detection. Mycocerosic acids are identified by simple one-dimensional electron capture gas chromatography of pentafluorobenzyl esters, with the use of negative-ion chemical ionisation gas chromatography in indecisive cases. Conversion of mycolic acids to anthrylmethyl esters produces compounds which are suitable for sensitive detection by fluorescence high-performance liquid chromatography. Application of all three of these methods to sputum samples from tuberculosis patients gave profiles characteristic of Mycobacterium tuberculosis.

Chromatography, Gas↗
PubMed1994

Direct detection of the intracellular formation of carboxyphosphamides using nuclear magnetic resonance spectroscopy.

31P nuclear magnetic resonance (NMR) spectroscopy was used in conjunction with cell perfusion techniques to monitor the intracellular chemistry of the cyclophosphamide (CP, CAS 6055-19-2) metabolites 4-hydroxy-cyclophosphamide (4-HO-CP) and aldophosphamide (AP) in U937 human histiocytic (CP-sensitive) and K562 human erythroleukemia (CP-resistant) cells. Similar experiments were carried out using the ifosfamide (IF, CAS3778-73-2) metabolites 4-hydroxyifosfamide (4-HO-IF) and aldoifosfamide (AIF). The hydroxy and aldehydic metabolites were generated by the triphenylphosphine reduction of 4-hydroperoxycyclophosphamide (4-HO2-CP) or 4-hydroperoxyifosfamide (4-HO2-IF) or by a spontaneous elimination/addition reaction involving water and 4-thiocyclophosphamide analogs 4-(2-hydroxyethyl) thiocyclophosphamide (4-ESCP) or mafosfamide. Cell death resulting from 4-HO-CP/AP perfusions was mimicked by perfusion with acrolein or an acrolein producing but non-alkylating, dechloro-CP analog. Acrolein toxicity was minimized by the presence of 2-mercaptoethanol or mesna (sodium 2-mercaptoethanesulfonate) in perfusion solutions as well as by fractional dose drug perfusions (sequential 2.5-3.0 h perfusions separated by cell washes with drug-free medium). The intracellular half-life for phosphoramide mustard (PM) at an intracellular pH value of 7.1 +/- 0.1 and an ambient probe temperature of 23 +/- 1 degree C in U937 cells was 2.1 h [k = (5.4 +/- 0.3) x 10(-3) min-1] and in K562 cells was 3.1 h [k = (3.7 +/- 0.4) x 10(-3) min-1]. Similar half-lives (2-4 h) were determined for intracellular isophosphoramide mustard (IPM). Fractional dose perfusion of U937 or K562 cells with 1.5 mmol/l 4-HO-CP/AP (generated from 4-HO2-CP) and 0.3 mmol/l mesna allowed for the observation of intracellular carboxyphosphamide (CBP); CBP was formed in higher concentrations in the CP-resistant K562 cells. Similar results were obtained using 4-ESCP and mafosfamide as sources of 4-HO-CP/AP. Identification of CBP was based on chemical shift, chemical stability, and membrane permeability studies of synthetic CBP. Concentrations of carboxyifosfamide (CBIF) formed in K562 cells were also greater than that in U937 cells.

Acrolein↗
PubMed1993

Direct detection of HIV-1 RNA in epidermal Langerhans cells of HIV-infected patients.

Human Langerhans cells (LC) are bone marrow-derived, HLA-DR+, CD1a+, and CD4+ dendritic antigen-presenting cells found in stratified squamous epithelia. As other members of the dendritic leukocyte family, to which they belong, LC have been reported as targets for HIV-1 infection. The aim of the present study was to investigate whether HIV-1 RNA is expressed in epidermal LC of HIV-1-infected patients. Bulk epidermal cell (EC) suspensions were prepared from skin of nine recently deceased AIDS patients and 11 seronegative controls. Purified LC (94 +/- 4% HLA-DR+ cells with no CD3+ cells, as assessed by flow microfluorimetry analysis) and LC-depleted EC were obtained by immunomagnetic separation using an anti-CD1a monoclonal antibody. Samples were analyzed for the presence of HIV-1 RNA by reverse transcription of a spliced mRNA region of the tat gene, followed by polymerase chain reaction amplification. HIV-1-spliced RNA was detected in LC from 6 of 9 patients examined, whereas LC-depleted EC fractions from the same patients were all negative. The results indicate that epidermal LC from HIV-seropositive patients actively transcribe HIV-1 proviral DNA, further supporting the hypothesis that HIV productively infected LC could serve as a reservoir of the virus in the epidermis and as a source for the infection of T lymphocytes.

Adult↗
PubMed1995

[Measurement of radical in irradiated experimental tumor: direct detection of ascorbate radical in mice using ESR].

We measured ascorbate radical (AR) produced by the reaction of ascorbic acid (Asc) with hydroxyl radical (.OH) or superoxide (O2-) after irradiation in normal muscle and SCC-VII tumor of C3H/He mice. AR can be measured using electron spin resonance (ESR) equipment and the dialysis method. The tube for collecting AR was inserted such that the dialysis membrane was in contact with the normal thigh or the center of the tumor lesion. The AR in the interstitial fluid around the membrane was collected through the dialysis membrane. After irradiation with 10 Gy, AR increased in both the normal muscle and tumor tissue; the percent increase was 53.1% for normal muscle tissue and 33.8% for tumor tissue. The maximum percent increases in AR in the normal muscle and the tumor tissue were 11.7 and 9.5% for 2.5 Gy, 28.5 and 18.5% for 5 Gy, 53.1 and 33.8% for 10 Gy, and 88.5 and 44.8% for 15 Gy, respectively. The amount of AR increased to maximums of 144.3% and 160.1% after treatment with H2O2 and FeCl2, respectively, while it decreased to minimums of 65.3% and 81.3% after treatment with superoxide dismutase (SOD) and catalase, respectively. These results suggest that the amount of .OH and O2- is reflected in the amount of AR production. This method is useful for the following reasons. First, no special treatment, such as freezing of the samples, and no administration of noxious agents are necessary. Second, irradiation using a dose of only several Gy shows an increase in the production of AR. Third, this method is less invasive.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗