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Biomedical subjects

R Kaiser

Publications and source records attributed to R Kaiser.

At least 163 records · Page 9Linked to original sources
PubMed1993

Diversification of HIV-1 strains after infection from a unique source.

In 1990, 7 hemophilia B patients were infected with human immunodeficiency virus type 1 (HIV-1) after exposure to a single common lot of clotting factor. The hypervariable regions V1 and V2 of the proviral env gene from the patients shared a homology between 97.5% and 100% at the time of seroconversion. To determine the in vivo diversification of these epidemiologically closely related virus strains, the patients were followed up in the early phase of HIV infection. Direct sequencing of the V1/V2 region in the env gene still revealed a very high degree of homology (96.5%-100%). In the case of the patient who showed the highest decrease of CD4+ cells, moderate genetic diversification of the virus was associated with a biological differentiation. The strain originally presenting two expressed substitutions displayed three more deviations 9 months after the first investigation (including one reversion to the consensus sequence). In addition, the virus that originally could not be cultivated could now be isolated as a low cytopathogenic agent. This study provides evidence that the high genetic homogeneity of HIV-1 observed at the time of seroconversion is maintained as a predominant consensus sequence in the following so-called latent phase of infection.

Amino Acid Sequence↗
PubMed1993

Intrathecal antibody synthesis in Lyme neuroborreliosis: use of recombinant p41 and a 14-kDa flagellin fragment in ELISA.

The intrathecal synthesis of IgM and IgG antibodies to Borrelia burgdorferi sonicate, to recombinant flagellin (41 kDa) and to a tryptic peptide of the flagellin (14-kDa fragment) was determined by ELISA in paired cerebrospinal fluid (CSF) and serum samples from 35 patients with Lyme neuroborreliosis (LNB) and in 10 patients with neurosyphilis. The antibody index (AI = QBb/QIg) was calculated from the ratio between CSF/serum quotients for specific antibodies (QBb) and total immunoglobulins (QIg). For the examination of IgG antibodies, the sonicate ELISA was performed with and without pre-absorption with Treponema phagedenis. Of 35 patients with LNB, 31 had intrathecal IgG response to B. burgdorferi demonstrated by sonicate ELISA (24 after absorption of cross-reactive antibodies), 29 had a response demonstrated by flagellin ELISA and 21 of 35 by 14-kDa ELISA. In patients with neurosyphilis the AI (IgG) was elevated in the sonicate ELISA in 7 of 10 samples (none of 10 after absorption of cross-reactive antibodies), in the flagellin ELISA in 5 of 10 samples and in the 14-kDa ELISA in none of 10 samples. Intrathecal synthesis of IgM antibodies to B. burgdorferi was demonstrated in patients with neuroborreliosis by sonicate ELISA in 20 of 35 samples, by flagellin ELISA in 16 of 35 samples and by 14-kDa ELISA in 9 of 35 samples. No intrathecal synthesis of B. burgdorferi-specific IgM could be detected by any assay in patients with neurosyphilis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

GFAP-specific oligoclonal bands in the CSF of a patient with acute myelitis.

The specificity for GFAP (glial fibrillary acidic protein) of oligoclonal IgG bands in the CSF of a patient with acute myelitis was demonstrated by isoelectric focusing and affinity blotting. Findings were confirmed by western blotting using a monoclonal antibody to GFAP as a reference. Immune reactions to this astrocyte protein are considered as arising secondary to spinal cord tissue lesion.

Acute Disease↗
PubMed1992

Oral naloxone reduces constipation but not antinociception from oral morphine in the rat.

Oral administration of naloxone (10 mg/kg) antagonized the slowing of the intestinal transit caused by oral morphine (1, 2.5 and 5 mg/kg) in rats. Oral administration of naloxone (10 mg/kg) did not prevent the antinociceptive effect of orally administered morphine (2.5 mg/kg) in the tail-flick test carried out on rats. It is concluded that oral naloxone locally blocks the constipating effect of morphine, while it fails to reduce the central action of morphine due to extensive metabolization after oral administration.

Administration, Oral↗
PubMed1992

Separation and characterization of isoforms of DT-diaphorase from rat liver cytosol.

Rats were treated with 3-methylcholanthrene (MC) and DT-diaphorase from liver was partially purified on an azodicoumarol-Sepharose 6B column and applied to an FPLC-chromatofocusing column in order to resolve isoforms. Six peaks showing significant DT-diaphorase activity were eluted from this column with a pH gradient between 7.30 to 4.80. The amino acid compositions of the two major peaks (II and VIb) were found to be nearly identical, suggesting existence of isoforms rather than isozymes of DT-diaphorase. The isoforms of DT-diaphorase showed broad substrate specificities towards four different quinones (menadione, vitamin K-1, benzo(a)pyrene 3,6-quinone and cyclized-dopamine ortho-quinone), although quantitative differences in the specific activities were also found. All isoforms are glycoproteins but contain different carbohydrates. Thus isoform II reacts with biotinylated lectins which are specific for N-acetylgalactosamine, mannose, fucose and galactosyl(beta-1,3)N-acetylgalactosamine, while isoform VIb reacts only with biotinylated lectins specific for mannose and N-acetylgalactosamine. Separation of DT-diaphorase isoforms from control rat liver cytosol using FPLC-chromatofocusing revealed that the induction of the isoforms is not uniform, since isform II was not found and the major isoform was composed of three peaks, whereas the major isoform of DT-diaphorase from liver cytosol of rats treated with 3-methylcholanthrene was composed of only two peaks.

Amino Acids↗
PubMed1992

Identification of clusters of biallelic polymorphic sequence-tagged sites (pSTSs) that generate highly informative and automatable markers for genetic linkage mapping.

Using a combination of denaturing gradient gel electrophoresis and direct DNA sequencing, we have found that multiple (4 to 7) biallelic sequence polymorphisms can be located within short DNA segments, 300 to 2400 bp. Here, we report on the identification of three clusters of DNA polymorphisms, one in each of the constant regions of the human T cell receptor alpha and beta gene complexes on human chromosomes 14 and 7, respectively, and a third among the human t-RNA genes on human chromosome 14. The frequency of these polymorphisms and the extent of linkage disequilibrium between individual polymorphisms have been determined using a semiautomated DNA typing system combining DNA target amplification by the polymerase chain reaction with the analysis of internal sequence polymorphisms by a colorimetric oligonucleotide ligation assay. We have found that individual biallelic polymorphisms in each cluster are often in partial linkage disequilibrium with one another. This partial linkage disequilibrium permits the combined use of three to four markers in a cluster to generate a haplotype with high levels of heterozygosity, 71 to 88%. Therefore, clusters of physically linked biallelic polymorphisms provide an automatable and highly informative type of genetic marker for general linkage analysis as well as an attractive alternative marker system for fine-point mapping of disease-causing genes and phenotypic traits relative to their framework locations in the genome.

Alleles↗
PubMed1992

Hereditary progressive dystonia with diurnal fluctuation (Segawa's syndrome)--an unusual case.

A young girl with hereditary progressive dystonia with diurnal fluctuation or Segawa's syndrome, completely handicapped and confined to a wheelchair between the age of 5 and 9, revealed an unusually slow response to levodopa. The ability to walk returned only after 12 to 14 months of treatment. Apart from peculiarities of behaviour due to longstanding immobility and ensuing parental overprotection, there were no psychological or mental abnormalities. Other organic diseases were ruled out. A series of regular follow-ups over the course of 7 years was performed. While residual and irregular day-to-day variation of functional capacities almost disappeared after conversion to a preparation with a decarboxylase inhibitor, some mild neurological abnormalities and a slight choreic hyperkinesia persisted with doses providing functional results. The patient today leads an almost normal teenage life and has performed well in school.

Body Weight↗
PubMed1992

Steady-state dependence of stress on cross-bridge phosphorylation in the swine carotid media.

Tonic contractions of the swine carotid media are typically characterized by initial transients in myoplasmic [Ca2+] and cross-bridge phosphorylation followed by force maintenance with reduced intracellular [Ca2+] and cross-bridge phosphorylation ("latch"). The presence of effective mechanisms in the carotid media to limit steady-state myoplasmic [Ca2+] and cross-bridge phosphorylation to modest increases over resting values has limited experimental attempts to determine the dependence of active stress (force/tissue cross-sectional area) on cross-bridge phosphorylation. In this study, we employed stimulation protocols that combined effective contractile agonists with inhibitors of Ca2+ extrusion or sequestration to achieve high steady-state levels of cross-bridge phosphorylation (up to 60%). Increases in cross-bridge phosphorylation from 30 to 60% were not associated with significant increases in stress in agreement with the predictions of Hai and Murphy [Am. J. Physiol. 254 (Cell Physiol. 23): C99-C106, 1988] four-state cross-bridge model for the carotid media. Thus cross-bridge phosphorylation may suffice to determine force generation in vascular smooth muscle if both phosphorylated and dephosphorylated attached cross bridges (or latch bridges) contribute to active stress.

Animals↗
PubMed1992

Pediatric emergency information sheet using a microcomputer.

Calculating the appropriate dosage of a drug and the right equipment size during an emergency situation can be a time-consuming, frustrating, and error-prone process, considering the shortage of time during a resuscitation. A microcomputer program was developed to aid in the care of pediatric patients in emergency or 'code' situations. This is accomplished by use of a printout of a patient-specific chart for most needed critical care drugs and equipment used during an emergency. This program is written in "C" language and is menu-driven.

Child, Preschool↗
PubMed1992

[Detection of varicella zoster virus infections using polymerase chain reaction].

The polymerase chain reaction (PCR) was used to detect varicella zoster virus (VZV) DNA in vesicle samples from patients with varicella and zoster. Primers and the oligonucleotide probe were chosen from the region of the immediate early gene 63. Procedures for preparing the DNA from the specimens were omitted, and the amplified DNA was directly detected in ethidium bromide-stained polyacrylamide or agarose gels, thus providing a rapid and less laborious assay. A total of 66 vesicle specimens including 3 crusts (collected on days 1-14 after the onset of exanthem) were tested by the simplified VZV-PCR, and 64 (97%) were positive. When the direct visualization of the amplified DNA was confirmed by DNA hybridization, a non-radioactive hybridization assay involving a digoxigenin-labelled oligonucleotide probe and detection by chemiluminescence proved as adequate as a radioactive hybridization assay. Thus, the VZV PCR described appears to be a useful diagnostic test for detecting and identifying varicella zoster virus.

Antibodies, Viral↗
PubMed1992

Structural characterization of rabbit brain ubiquitin.

Ubiquitin has been isolated and purified from rabbit brain using gel permeation and reverse-phase high-performance liquid chromatography. The 76-residue protein exhibits one difference towards a murine form, is identical to other characterized vertebrate ubiquitins, and confirms an extensive conservation of the ubiquitin structure. No positional microheterogeneities were detectable between two sub-forms.

Amino Acid Sequence↗
PubMed1991

Diagnosis of acute and latent varicella-zoster virus infections using the polymerase chain reaction.

A simplified assay for the diagnosis of varicella-zoster virus (VZV) infections based on the polymerase chain reaction (PCR) is described. Omitting the procedures for extraction and purification of DNA, the crude vesicle fluid materials were used for PCR. Moreover, hybridization was not necessary for detection of the amplification products because they were already visible after ethidium bromide staining of the electrophoresis gel. Results could therefore be obtained within one day. In comparison to virus isolation, PCR proved much more rapid, highly sensitive, and specific. DNA extraction and a double PCR assay with nested primers were necessary for detection of latent VZV infections in trigeminal and thoracic ganglia. The data suggest that the procedures described are universally applicable to several types of specimens dependent on the calculated amount of target DNA.

Acute Disease↗
PubMed1991

Immunoglobulin G subclass preference of intrathecally produced HIV-specific oligoclonal antibodies.

Cerebrospinal fluid (CSF) and serum samples from 16 HIV-seropositive subjects were examined by ELISA and isoelectric focusing for the presence of HIV-specific immunoglobulin G (IgG) subclass antibodies. Autochthonous synthesis of IgG in the CSF was demonstrated in 11 patients. Intrathecally synthesized antibodies specific for individual HIV structural proteins were largely restricted to IgG1 (10 of 11 patients). One patient revealed additional local synthesis of IgG2 antibodies related to HIV-p15. In another patient locally produced antibodies specific for HIV consisted entirely of IgG4. In this patient amounts of locally produced antibodies were too low to be detected by routine procedures (calculation from an evaluation graph). No local synthesis of HIV-related IgG3 was demonstrated in any patient. Further studies will be needed to show whether determination of IgG-subclass-restricted antibodies to HIV is of prognostic value.

Adult↗
PubMed1991

Human class III alcohol dehydrogenase/glutathione-dependent formaldehyde dehydrogenase.

The class III human liver alcohol dehydrogenase, identical to glutathione-dependent formaldehyde dehydrogenase, separates electrophoretically into a major anodic form (chi 1) of known structure, and at least one minor, also anodic but a slightly faster migrating form (chi 2). The primary structure of the minor form isolated by ion-exchange chromatography has now been determined. Results reveal an amino acid sequence identical to that of the major form, suggesting that the two derive from the same translation product, with the minor form modified chemically in a manner not detectable by sequence analysis. This pattern resembles that for the classical alcohol dehydrogenase (class I). Hence, the chi 1/chi 2 multiplicity does not add further primary forms to the complex alcohol dehydrogenase system but shows the presence of modified forms also in class III.

Aldehyde Oxidoreductases↗
PubMed1991

Affinity immunoblotting: rapid and sensitive detection of oligoclonal IgG, IgA and IgM in unconcentrated CSF by agarose isoelectric focusing.

Two methods for the investigation of oligoclonal immunoglobulin bands in cerebrospinal fluid are compared. Isoelectric focusing (IEF) in agarose gels combined with a highly sensitive affinity immunoblotting proved to be superior to PAGE-IEF and silver staining regarding detection sensitivity and expenditure of labour. The procedure presented here allows examination of oligoclonal bands not only of IgG, but also of IgA and IgM antibodies in less than 4 h. Oligoclonal IgM bands could be detected in 6 patients with neuroborreliosis or neurosyphilis as well as in one patient with a peripheral neuropathy where other electrophoretic methods, including immunoelectrophoresis, were negative. Oligoclonal IgA bands were demonstrated only in 2 patients with a bacterial infection of the CNS. In patients with multiple sclerosis amounts of IgM and IgA in the CSF were too low to allow investigation of oligoclonal IgM or IgA bands.

Dithiothreitol↗