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Biomedical subjects

A Perl

Publications and source records attributed to A Perl.

At least 55 records · Page 3Linked to original sources
PubMed1991

Protoplast fusion mediated transfer of oligomycin resistance from Nicotiana sylvestris to Solanum tuberosum by intergeneric cybridization.

We have successfully bridged the intergeneric barriers between Nicotiana and Solanum with respect to chondriome transfer. To enable this transfer we utilized the donor-recipient protoplast-fusion procedure. Consequently protoplasts of a Nicotiana sylvestris line with putatively oligomycin-resistant mitochondria (line OliR38) were used as irradiated chondriome donors and iodoacetate-treated protoplasts of Solanum tuberosum cv. Desiree served as recipients. The plated fusion products as well as their derived colonies and calli were exposed to gradually increasing levels of oligomycin. The resulting plantlets had potato morphology and were analyzed with respect to their mitochondrial DNA and chloroplast DNA. Fifteen out of 50 regenerated plants were verified as true cybrids. Detailed analyses of one cybrid revealed chondriome components from the oligomycin-resistant donor line, OliR38, but retention of the plastome of potato. This cybrid was oligomycin-resistant as revealed by root-culture analysis. It was thus verified that due to selection, chondriome components could be transferred from a N. sylvestris donor into a cybrid having all the phenotypic features controlled by the nucleus of the recipient fusion partner (S. tuberosum).

Blotting, Southern↗
PubMed1990

[Clonal immunoglobulin rearrangement in patients with essential cryoglobulinemia].

'Essential' cryoglobulinemias (EC) are characterized by the precipitation of immunoglobulins (Igs) from the sera of patients at temperatures below 25 degrees C. The cryoprecipitate of type I EC patients is comprised of a monoclonal Ig while that of patients with type II or 'mixed' EC contains monoclonal auto-antibodies with rheumatoid factor activity. In order to define if the high cryoglobulin production rate is related to a clonal B-cell expansion the rearrangement of Ig genes was investigated by Southern blot analysis of DNA extracted from peripheral blood lymphocytes of EC patients. Clonal expansion of B cells could be detected using Ig light and heavy chain specific DNA probes in 3/4 patients with type I EC and 4/12 patients with type II EC. In the group of patients with clonal Ig gene rearrangements, in two cases with type I EC and one case with type II EC, alterations of the c-myc locus was also noted. Demonstration of clonal B-cell expansions in EC patients shows that the clonal type of Ig gene rearrangements is not a unique marker of malignant lymphomas. Since malignant B-cell lymphomas can develop in a small number of EC cases, the follow-up of these patients should be pursued indefinitely.

Cryoglobulinemia↗
PubMed1990

[Polymerase chain reaction in clinical diagnosis].

The polymerase chain reaction (PCR) is a novel method that amplifies selective sequences of DNA or RNA molecules with unparalleled efficiency. The specificity of PCR amplification is based on two oligonucleotide primers which flank the DNA fragment to be multiplied and hybridize to opposite strands. Repeated cycles of thermal denaturation, primer annealing, and enzymatic extension by the heatstable Taq DNA polymerase result in exponential augmentation of the target DNA. PCR is simple, rapid, and highly sensitive. The nucleic acid content of a single cell is sufficient to detect a particular sequence. This method has an enormous impact on the detection of genetic mutations, sequence polymorphisms and infective agents. This review depicts the mechanism of PCR and explores its applications in clinical diagnostics.

DNA, Recombinant↗
PubMed1990

No evidence for human T-cell leukemia virus type I or human T-cell leukemia virus type II infection in patients with multiple sclerosis.

The involvement of human T-cell leukemia viruses (HTLVs) in the pathogenesis of 18 Hungarian patients with multiple sclerosis was investigated. No antibody to HTLVs could be detected in any of the patients. Furthermore, using polymerase chain reaction under highly sensitive conditions, neither HTLV-I DNA nor HTLV-II DNA could be noted in peripheral blood lymphocytes of the patients. Our data do not support a causal association of HTLV-I or HTLV-II with multiple sclerosis.

Adult↗
PubMed1990

Rearrangement of the T-cell receptor alpha, beta and gamma chain genes in chronic lymphocytic leukemia.

Simultaneous expression of mature B-cell and T-cell markers and subsequent abrogation of expression of the T-cell surface markers by cytotoxic chemotherapy was reported earlier in a patient (TG) with chronic lymphocytic leukemia (CLL). In addition to rearrangements of the immunoglobulin (Ig) gene loci correlating with phenotypic data, the T-cell receptor (TCR) alpha, beta and gamma chain genes also displayed clonal rearrangements in peripheral blood lymphocyte DNA of TG. The present case shows that in CLL cells not only the expression of B-cell and T-cell specific differentiation antigens but also the rearrangement of Ig as well as TCR alpha, beta and gamma genes may occur simultaneously.

Aged↗
PubMed1990

Prevention of a side effect of epidural morphine by epidural steroid administration in cesarean section.

In order to evaluate the effect of preventive corticosteroid on the occurrence of pruritus after epidural anesthesia with morphine, we studied 95 patients undergoing cesarean section. Thirty-seven patients (group I) were given 20 mg of bupivacaine 0.5% for the operation and 2 mg of morphine hydrochloride with 50 mg of Ultracortene-H immediately after the operation and 24 h later, and 58 patients (group II) were given epidural bupivacaine during the operation and epidural morphine hydrochloride immediately after the operation and 24 h later without Ultracortene-H. Only 8.1% of group I patients had pruritus after the injection compared to 20.6% in group II. We suggest that the addition of 50 mg Ultracortene-H to 2 mg epidural morphine analgesia after the operation might prevent severe forms of pruritus.

Anesthesia, Epidural↗
PubMed1989

Detection and cloning of new HTLV-related endogenous sequences in man.

Human T-cell leukemia virus (HTLV) type I-related endogenous sequences (HRES) have been cloned from a human genomic library. HRES-1/1 is present in DNA of all normal donors examined. By nucleotide sequence analysis, HRES-1/1 contains two potential open reading frames capable of encoding a p25 and a p15. A 684 bp flanking region 5' from the first ATG codon of p25 contains a TATA-box, a poly-adenylation signal, a putative tRNA primer binding site, and inverted repeats at locations which are typical of a retroviral long terminal repeat. Phylogenetic analysis suggests that HRES-1/1 entered the genome in primates, presumably as an exogenous retrovirus. From the deduced amino acid sequence of HRES-1/1 p25, residues 6-36 show a sequence homology of 32% and 39% to gag region segments of HTLV-I and HTLV-II, while residues 104-139 display a sequence homology of 33% and 28% to the gag regions of human immunodeficiency virus type 2 (HIV-2) and feline sarcoma virus (FSV), respectively. This suggests that the original exogenous virus infecting primate may be chimeric in structure. The HRES-1/1 genomic locus is transcriptionally active in lymphoid cells, melanoma cells, and embryonic tissues.

Amino Acid Sequence↗
PubMed1989

Detection and mapping of polymorphic KpnI alleles in the human T-cell receptor constant beta-2 locus.

Southern blot analysis with human T-cell receptor (TcR) beta-chain specific cDNA probes revealed two novel allelic forms of the TcR beta-2 gene locus. Three different genotypes were noted based on the presence of polymorphic KpnI restriction fragments: I, 5.7 kb fragment only; II, 3.9 kb and 1.8 kb fragments only; III, all three polymorphic fragments. This hybridization pattern suggested that the presence or absence of a polymorphic KpnI site within the 5.7 kb fragment defines the two different allelic forms of the TcR beta chain locus. By Southern blot analysis of genomic DNA from T-cell lines with deleted C-beta-1 regions and computer-assisted restriction site mapping of germline and cDNA sequences of the C-beta-2 locus, the polymorphic KpnI site was localized at 24 bp 5' to the third exon of the C-beta-2 gene. It was determined that the polymorphic KpnI site and the earlier described polymorphic BglII site located 5' to the C-beta-2 gene are not co-inherited. No difference was noted in distribution of the KpnI genotypes and allelic frequencies between 26 normal individuals and 22 patients with systemic lupus erythematosus. However, this newly characterized polymorphism of the TcR locus should provide a useful tool to analyse the role of inherited genetic variations in the function of T lymphocytes under normal and pathological conditions.

Alleles↗
PubMed1989

Clonal B cell expansions in patients with essential mixed cryoglobulinaemia.

In essential mixed, type II, cryoglobulinaemia (EMC) monoclonal autoantibodies with rheumatoid factor activity are synthesized at an accelerated rate by non-malignant B lymphocytes. In order to determine if the high cryoglobulin production rate is related to a clonal B cell expansion, cell surface markers of peripheral blood lymphocytes (PBL) were analysed by flow cytometry and the rearrangement of immunoglobulin (Ig) genes was investigated by Southern blot analysis of DNA extracted from the PBL of 12 EMC patients. Clonal expansion of B cells could be detected using DNA probes specific for the c kappa, c-mu, and JH genes in four out of 12 patients, two of whom also showed specific expansions of mu heavy and kappa light chain bearing cells using flow cytometry. The rearrangement of the c-myc locus was also noted in one of the patients with detectable Ig gene rearrangements. Demonstration of clonal B cell expansions in EMC patients shows that the clonal type of Ig gene rearrangements are not unique markers of malignant lymphomas but may also occur in autoimmune lymphoproliferative disorders. Since malignant B cell lymphomas can develop in a small number of EMC cases, the follow-up of these patients should be pursued indefinitely.

Adult↗
PubMed1987

Aberrant immunoglobulin and c-myc gene rearrangements in patients with nonmalignant monoclonal cryoglobulinemia.

The status of the immunoglobulin (Ig) genes was investigated in patients with idiopathic nonmalignant monoclonal IgG cryoglobulinemia (NCG). In NCG, monoclonal antibodies are synthesized at an accelerated rate by nonmalignant B lymphocytes. In order to determine whether this high production rate is related to a clonal B cell expansion, the rearrangement of the Ig genes was investigated by Southern blot analysis of genomic DNA extracted from the peripheral blood lymphocytes of four NCG patients. In three of four (VI, BR, and CH) clonal expansion of B cells was detected using probes specific for the c kappa, JH, c gamma 4 genes (in accordance with detecting IgG kappa cryoproteins in these patients). BamHI digestion of DNA from VI and BR produced three rearranged fragments which cohybridized with JH and c mu probes. This finding suggested the presence of additional nonsecretory B cell clones and/or disruption of the gene segments spanned by and detected with the probes. In VI the idiotype of the IgG cryoglobulin was also detected in association with IgM in the supernatant of Epstein-Barr virus-stimulated B lymphocytes using a murine monoclonal anti-idiotypic antibody. In addition, the possibility of aberrant gene rearrangements was supported by noting the alteration of the c-myc gene locus in genomic DNA from peripheral blood leukocytes of VI and CH. Northern blot analysis of RNA isolated from peripheral blood B cells of VI and CH demonstrated aberrant transcripts of the c-myc gene, showing an active role of the altered c-myc locus. Detection of c-myc rearrangement in NCG patients clearly shows that this event may not be a final step in malignant B cell transformation; however, it may be related to the clonal expansion and high rate of cryoglobulin synthesis of nonmalignant B lymphocytes.

Adult↗
PubMed1987

Effect of (+)cyanidanol-3 on cellular immune reactions and on superoxide dismutase activity in vitro.

Immunological and antioxidant effects of the widely used hepatoprotective agent (+)cyanidanol-3 were studied in a complex in vitro test system using isolated peripheral blood lymphocytes of patients with chronic alcoholic liver disease and of healthy donors. In both groups in vitro treatment with (+)cyanidanol-3 inhibited lectin-induced lymphocyte blast transformation and chemiluminescence in a dose-dependent fashion and increased the superoxide dismutase-expression of lymphocytes without influencing the percentage of T and active T cells and antibody-dependent and spontaneous lymphocytotoxicity. The originally lower Con A-induced T cell mediated lymphocytotoxicity of patients was completely abolished, while no significant effect was seen using healthy donors' lymphocytes. (+)cyanidanol-3 markedly decreased the Con A-induced suppressor activity of patients' lymphocytes, without influencing that of normal cells. These results suggest that both antioxidant and immunomodulatory effects play an important role in the mechanism of action of (+)cyanidanol-3.

Adult↗
PubMed1987

Short-term stimulation of lymphocyte proliferation by indomethacin in vitro and in vivo.

The effect of short-term (up to 24 h) in vitro and in vivo treatment with indomethacin was studied on the blastogenesis of mouse spleen cells. Indomethacin in itself induced a strong proliferation of the lymphocytes starting after 6 h treatment both in vitro and in vivo. Besides, significantly enhanced the blastogenesis of splenocytes in response to various doses of PHA and Con A. The stimulation of lectin-induced lymphocyte proliferation occurred after indomethacin treatment both in vitro and in vivo. Indomethacin had no major effect on the distribution of Lyt-1+ and Lyt-2+ subsets within the spleen cell population. An important role of the prostaglandins in the early phase of lymphocyte activation is suggested.

Animals↗
PubMed1986

The low affinity 40,000 Fc gamma receptor and the transferrin receptor can be alternative or simultaneous target structures on cells sensitive for natural killing.

The role of the low avidity 40,000 dalton receptor for IgG (Fc gamma R) present on K562 and U937 cells in sensitivity to natural killing (NK) was studied by using a murine monoclonal antibody (mAb) specific for the 40,000 dalton Fc gamma R (alpha Fc gamma R mAb). Pretreatment of K562 target cells with intact alpha Fc gamma R mAb or its Fab fragment or anti-transferrin receptor (alpha TFR) mAb partially blocked in a dose-dependent manner, NK activity to K562 cells. However, combined pretreatment with alpha Fc gamma R and alpha TFR mAb completely blocked NK activity against K562 targets. As compared with K562 cells, lower levels of NK were elicited against Molt-4, U937, HL-60, and Daudi targets. Although NK activity to Molt-4 targets was not affected by alpha Fc gamma R mAb, it was fully prevented by pretreatment with alpha TFR mAb. In contrast, NK to U937 cells was not influenced by alpha TFR mAb, but it was strongly inhibited by alpha Fc gamma R mAb. The resistance of 3H-TdR-prelabeled adherent HEp-2 cells to natural cell-mediated cytotoxicity was not affected by either mAb. Lectin-dependent cell-mediated cytotoxicity (LDCC) against HEp-2 cells due to the presence of concanavalin A, and was completely abrogated by pretreatment of the targets with alpha TFR mAb, but was unaffected by alpha Fc gamma R mAb. By use of the flow cytometer, a significant correlation was detected between the relative expression of 40,000 dalton Fc gamma R and the susceptibility to NK, whereas the expression of TFR was discordant from NK sensitivity. As determined in the single cell cytotoxicity assay alpha Fc gamma R mAb reduced the frequency of target binding effector cells without affecting the number of dead bound targets. This pattern of inhibition was found against both K562 and U937 targets. Alternatively, alpha TFR mAb inhibited both binding and killing of K562 and Molt-4 targets. Because pretreatment of HEp-2 cells with alpha TFR mAb did not influence conjugate formation, the blocking of LDCC to HEp-2 cells by alpha TFR mAb can be related to post-binding events. These data show that although both the 40,000 dalton Fc gamma R and the TFR can be target structures for NK cell recognition, the TFR may also play an important role in the post-binding events.

Antibodies, Monoclonal↗
PubMed1986

Indomethacin abrogates the suppression by cyclosporin A of lectin-dependent cell-mediated cytotoxicity to HEp-2 cells.

The effects of cyclosporin A, prostaglandin E1 and indomethacin were studied on lectin-dependent cell-mediated cytotoxicity (LDCC) against adherent HEp-2 human epipharynx carcinoma target cells. LDCC activity by human peripheral blood lymphocytes was evaluated by detachment from the monolayer of [3H]thymidine-prelabelled HEp-2 cells in a 24-h assay at 50:1 effector:target cell ratio in the presence of 25 micrograms/ml concanavalin A. Under these conditions, but without concanavalin A, considerable natural cell-mediated cytotoxicity was not elicited although LDCC was significantly augmented in the presence of concanavalin A. Addition of both cyclosporin A (0.1, 1.0 or 10 micrograms/ml) and prostaglandin E1 (10(-8), 10(-7) or 10(-6) M) dose-dependently suppressed LDCC activity. Indomethacin (0.1, 1.0 or 10 micrograms/ml) did not in itself influence LDCC although suppression of LDCC by cyclosporin A, but not prostaglandin E1, was abrogated in the presence of indomethacin. Similar to indomethacin, acetyl salicylic acid also reversed the inhibition of LDCC by cyclosporin A. In parallel experiments, cyclosporin A elicited a more than two-fold increase of prostaglandin E production under LDCC assay conditions as measured by radioimmunoassay. Contrary to LDCC, depression of concanavalin A induced blastogenesis by cyclosporin A was not influenced by indomethacin, suggesting that the inhibition by cyclosporin A of LDCC and concanavalin A-induced blastogenesis proceed via different mechanisms.

Carcinoma, Squamous Cell↗
PubMed1986

Continuous flow ventilation without respiratory movement in cat, dog and human.

The insufflation of oxygen at 1 litre kg-1 min-1 via two endobronchial catheters (called continuous flow ventilation (CFV)) maintained a normal PaCO2 and a constant PaO2 in anaesthetized paralysed dogs and in five out of seven cats. In two cats with a high carbon dioxide production, CFV failed to maintain carbon dioxide homeostasis since gas flows greater than 1 litre kg-1 min-1 caused thoracic distension and a decrease in arterial pressure. In five patients, endobronchial insufflation of oxygen 0.5 litre kg-1 min-1 caused approximately a 30% decrease in the increase in PaCO2 compared with apnoeic oxygenation (P less than 0.05) during a period of 6 min. CFV at 1 litre kg-1 min-1 can be used for physiological measurement without respiratory movement while maintaining blood-gas homeostasis in dogs and in cats with a normal carbon dioxide production. Ethical constraints have so far prevented the investigation of the effects of comparable gas flows in man.

Adult↗
PubMed1986

Combined continuous-flow, normal, and high-frequency ventilation.

Ten anesthetized, paralyzed dogs were ventilated at 10 breath/min and 100 cycle/min with a valveless ventilator. When fresh respiratory gas was supplied at the carina or insufflated into the bronchi, there was a significant (p less than .05) reduction in PaCO2, which was maximal during high-frequency ventilation (HFV) with twice normal minute volume. There was no statistically significant advantage in using a more complicated system for bronchial insufflation compared with supplying the fresh gas through a single tube near the carina. The improvement in ventilation and oxygenation during HFV with gas at the carina was reduced markedly when normal lungs were injured by oleic acid. Thus, when peak airway pressure was minimized during HFV, there was a further improvement in gas exchange without an appreciable increase in airway pressure when the gas was supplied at the carina.

Animals↗