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Biomedical subjects

R Martin

Publications and source records attributed to R Martin.

At least 505 records · Page 28Linked to original sources
PubMed1989

Expression of the bovine leukemia virus transactivator protein p34 by a recombinant vaccinia virus.

In order to characterize the bovine leukemia virus transactivator protein, a recombinant vaccinia virus (v-LOR) containing the BLV post-envelope long open reading frame was constructed. v-LOR was shown to encode a functional protein able to transactivate the BLV long terminal repeat-directed gene expression in the infected cells. The encountered level of transactivation was about one third of that measured in BLV-infected fetal lamb kidney cell lysates.

Animals↗
PubMed1989

Virus-specific and autoreactive T cell lines isolated from cerebrospinal fluid of a patient with chronic rubella panencephalitis.

Using a recently described technique for expanding of human T lymphocyte populations from cerebrospinal fluid (CSF), we investigated the local cellular immune response in a patient with chronic rubella panencephalitis. A total of 328 T cell lines (TCLs) was established by seeding CSF cells at limiting dilution into histoplates in the presence of irradiated feeder cells and phytohemagglutinin (PHA)-containing conditioned medium. 80% of TCLs expressed the CD4+CD8-, 5% the CD4-CD8+ phenotype and 15% of TCLs contained different proportions of CD4+ and CD8+ cells. Of 191 TCLs analyzed, 85 were cytotoxic, as shown by their lectin-dependent cytotoxicity against allogeneic uninfected target cells. Eight of them demonstrated specificity for the autologous, rubella virus-infected target cells. When tested for antigen-specific proliferative activity, 26 TCLs responded to rubella antigen, 16 TCLs reacted to myelin basic protein (MBP), four TCLs to proteolipid protein (PLP), four to galactocerebrosides and two to actin. Fourteen out of 16 MBP-specific TCLs also responded, to a minor degree, to rubella antigen and/or actin. The results showed that the persisting rubella infection had given rise to autoreactive T cells. Virus-induced autoreactivity to brain antigens may be an important pathogenetic mechanism in other chronic inflammatory disorders of the CNS.

Actins↗
PubMed1989

Chemical equivalence of two polyetherpolyurethane foams as a vehicle for povidone-iodine solution: kinetic model for the loss of available iodine.

The loss of available iodine from povidone-iodine solution stored in contact with two different polyetherpolyurethane foams was monitored as a function of time and temperature. Statistical evaluation of the results for the four temperatures studied [ambient (25 degrees), 30, 45 and 55 degrees C] indicated the chemical equivalence of the two foams as storage and delivery systems for povidone-iodine solution in terms of solution stability. In addition, application of a first-order kinetic model to the data produced an acceptable fit. An Arrhenius-type evaluation of the resulting rate constants yielded a linear relationship which was shown to be useful for predicting loss of available iodine under ambient temperature conditions of storage.

Drug Stability↗
PubMed1989

Hemolysis during cardiopulmonary bypass.

Hemolysis of red blood cells is a problem during cardiopulmonary bypass. The present study was undertaken to evaluate the influence of the priming solution and of the initial acceleration of the pump on red blood cell trauma and hemolysis. Eighty adult patients undergoing coronary artery grafting with cardiopulmonary bypass (CPB) were randomly assigned to one of four groups according to the nature of the priming solution and the initial speed of CPB flow (time from the start to the full calculated flow): group 1, lactated Ringer's (LR) with 5% dextrose (5%D), 1 minute; group 2, LR5%D, 2 minutes; group 3, LR, 1 minute; group 4, LR, 2 minutes. Plasma hemoglobin was found to be 4 times higher in group 1 than in the three other groups (P less than 0.001). It is concluded that there is an interaction between the presence of glucose in the priming solution and the initial acceleration of pump flow. The combination of LR5%D prime with a short time interval to full pump flow leads to a significant degree of hemolysis.

Adult↗
PubMed1989

Traditional herbal medicines--the role of polyphenols.

The polyphenol composition of some traditional herbal remedies is reviewed. Polyphenols probably act in such remedies by virtue of their astringent action and current views on the molecular basis of this property are outlined and discussed.

Chemical Phenomena↗
PubMed1989

Pulmonary function test study and after spinal fusion in young idiopathic scoliosis.

A homogeneous population of 42 women with idiopathic scoliosis (mean age, 20.8 years and mean major thoracic curve of 58.2 degrees) had a complete pulmonary function test (PFT) at rest before, and a minimum of 3 years after, spinal fusion (mean, 7.7 years) to evaluate the effect of scoliosis and its surgical correction on PFT at rest. A multifactorial analysis showed that only the vital capacity (VC) was significantly lowered to 81% of predicted value (P less than 0.05). All of the other parameters of pulmonary volumes, flow, and gas exchanges, where corrected for the loss of lung volume, were within normal limits, showing pure restrictive changes in this population. Double-major curves were more severe, but no significant difference in PFTs were found with single thoracic curves. Curves over 50 degrees had significantly lower VC. The surgical correction of 40% is permanent and the functional improvement in postoperative vital capacity (VC) of 12% is significant (P less than 0.05). Other factors, such as the time between the two evaluations, the age of the patient, pelvic obliquity, trunk imbalance, and degree of kyphosis did not have any correlation with the observed changed on any of the PFT results. Therefore, early correction by spinal fusion in idiopathic scoliosis brings on some improvement of the vital capacity at rest and may prevent deterioration with progression of the curve.

Adolescent↗
PubMed1989

Autoimmunity in Lyme disease: molecular cloning of antigens recognized by antibodies in the cerebrospinal fluid.

In inflammatory disease of the central nervous system (CNS), oligoclonal bands of immunoglobulin with restricted heterogeneity can often be observed in cerebrospinal fluid (CSF) samples. These antibodies can be directed against the disease inducing pathogen or might be autoreactive and involved in the process of brain inflammation and demyelination. We used a molecular biology approach to characterize these antibody responses in patients with Lyme disease. This disorder is caused by infections with the spirochete Borrelia burgdorferi which is transmitted by ticks. Lyme disease can be associated with neurological symptoms due to inflammation of the central and peripheral nervous system. Phage lambda gtll expression libraries from B. burgdorferi and human brain were screened with cerebrospinal fluid antibody probes from patients with Lyme disease. We obtained recombinant phage clones encoding antigenic proteins from both B. burgdorferi and human CNS libraries. Thus, in this study two patients with chronic Lyme disease produced antibodies against recombinant B. burgdorferi as well as against CNS proteins, and the generation of this transient autoimmune response might be essential to the development of demyelinating disease.

Antibodies, Bacterial↗
PubMed1989

Parental issues in feeding young children with bronchopulmonary dysplasia.

This study examined the feeding issues that parents of 11 children with bronchopulmonary dysplasia (BPD) identified and explored the informational bases or criteria for decisions to initiate, continue, and/or terminate the feeding. An oral feeding by the parents was videotaped and replayed to assist in interviewing the parents regarding the decisions they had made during the feeding. Six types of feeding issues were identified. The smoothness or amenability of the child's feeding behavior was most frequently expressed as important, and about half of the parents mentioned the child's dietary intake as an issue. Most parents consistently tried to maintain the child's eating and to achieve a predetermined amount of nutritional intake. Over half the parents were concerned about adequacy of the child's nutrition, and many were concerned about their child's acceptance of or resistance to food. Parents did not express concern about their child's development but were concerned about their child's somatic growth. Parents' concern about feeding behaviors requires joint problem-solving by nurses and parents. Whether use of decision criteria that refer to the child's behavior rather than a predetermined amount of food is possible for parents and likely to contribute to reduced vomiting and resistive behavior and increased dietary intake needs further study.

Bronchopulmonary Dysplasia↗
PubMed1988

Kinetics of bimolecular decay of alpha-tocopheroxyl free radicals studied by ESR.

The kinetics of bimolecular decay of alpha-tocopheroxyl free radicals (T) was studied by ESR mainly in ethanol and heptanol solvents. A second-order kinetic law was observed during the whole course of reaction (-d[T]/dt = 2k[T]2) and the following rate constants were determined with good accuracy in the temperature range 281-321 K: ethanol: log(2k) = 8.2 +/- 0.5--(6.6 +/- 0.7 kcal/mol)/(2.3RT) M-1.s-1; heptanol: log(2k) = 6.1 +/- 0.4--(4.3 +/- 0.6 kcal/mol)/(2.3RT) M-1.s-1. The global rate constant clearly increases with solvent polarity.

Electron Spin Resonance Spectroscopy↗
PubMed1988

Borrelia burgdorferi--specific and autoreactive T-cell lines from cerebrospinal fluid in Lyme radiculomyelitis.

In 3 patients with Lyme radiculomyelitis, cellular immune reactions of cerebrospinal fluid (CSF) lymphocytes were analyzed. Phenotypic analysis of CSF cells demonstrated that the majority were T cells (CD3+) of the helper/inducer subset (CD4+). These T cells were directly expanded from the CSF by limiting dilution. A total of 505 T-cell lines were tested for Borrelia burgdorferi (Bb)-specific proliferation and also partly tested for reactivity to a panel of central and peripheral nervous system antigens. Proliferative assays revealed 33 of them to be Bb specific, 16 to be specific for myelin basic protein, 16 to be specific for peripheral myelin, 1 to be specific for cardiolipin, and 2 to be specific for galactocerebrosides. The antigen-specific proliferation was restricted by autologous human leukocyte antigen (HLA) class II molecules. The majority of CSF-derived T-cell lines stained positively for CD3, CD4, and HLA class II antigens and negatively for CD8 (cytotoxic/suppressor subset). One T-cell line provided help for the production of specific IgG by autologous B cells and secreted gamma-interferon upon stimulation with Bb antigen in the presence of autologous antigen-presenting cells. These data show that in patients with severe neurological manifestations of late Lyme disease, not only Bb-specific T-cell lines but also T cells reactive to central or peripheral nervous system autoantigens can be found.

Adult↗
PubMed1988

Opiate binding differentially associated with oxytocin and vasopressin nerve endings from porcine neurohypophyses.

We examined opioid binding in fractions with disconnected nerve endings (secretosomes) which were prepared from porcine neurohypophyses by centrifugation in a discontinuous Percoll gradient. Specific (= displaceable) binding was observed with 3H-etorphine and with 3H-diprenorphine, two ligands with low selectivity for distinct opiate receptor subclasses. No displaceable binding was found with the prototypic mu- and delta-ligands 3H-dihydromorphine and 3H-(D-Ala, D-Leu) enkephalin. Displacement of 3H-diprenorphine binding was almost absent with the selective mu- and delta-ligands morphiceptin and ICI-174864. Partial displacement occurred with the selective kappa-ligand U-50488 and with dynorphin. Binding of 3H-etorphine was stereo-specific. 3H-diprenorphine binding was saturable with a KD between 2 and 4 nM. Maximum of opiate binding activity was detected in the fractions with accumulated secretosomes. By autoradiography specific 3H-diprenorphine binding is shown to be mainly associated with secretosomes. In imunocytochemical preparations an oxytocin antibody was immunoreactive in 85% of the secretosomes in the fraction with highest opiate binding. These fractions in radioimmunoassays exhibited the largest contents in oxytocin and low vasopressin levels. The data therefore suggest that in the porcine neurohypophysis opioid binding sites of the kappa-type occur in secretory endings presumably of the oxytocin type.

Animals↗
PubMed1988

Persistent intrathecal secretion of oligoclonal, Borrelia burgdorferi-specific IgG in chronic meningoradiculomyelitis.

In the cerebrospinal fluid IgG of five patients with lymphomeningoradiculitis (Bannwarth's syndrome) and radiculomyelitis studied by immunoblot technique an oligoclonal pattern was found. Most of these oligoclonal bands were specific for Borrelia burgdorferi. In patients suffering from chronic meningoradiculomyelitis, repeated CSF examination by this technique showed persistent secretion of identical IgG bands. Thus, the specific humoral immune response and the disease activity could be documented over the course of the disease.

Antibodies, Bacterial↗
PubMed1988

Release factor competition is equivalent at strong and weakly suppressed nonsense codons.

We have compared the competition between strong or weak suppressor tRNAs and translational release factors (RF) at nonsense codons in the lacI gene of Escherichia coli. Using the F'lacIZ fusions developed by Miller and coworkers, UAG, UAA, and UGA codons at positions 189 and 220 were efficiently suppressed by plasmid-borne tRNA(trp) suppressors cognate to each nonsense triplet. Introduction of a compatible RF 1 plasmid competed at UAG and UAA but not UGA codons. An RF2 expressing plasmid competed at UAA and UGA but had little effect at UAG. Release factor competition against weak suppressors was measured using combinations of noncognate suppressors and nonsense codons. In each case, release factor plasmids behaved identically towards poorly suppressed codons as they did when the same codons were efficiently suppressed. The implications for these studies on the role of release factors in nonsense suppression context effects are discussed.

Codon↗
PubMed1988

Kinetics of the diacetyl and 2,3-pentanedione reduction by diacetyl reductase (alpha-diketone reductase (NAD)) from Staphylococcus aureus.

The kinetic mechanism of diacetyl and 2,3-pentanedione reduction by diacetyl reductase from Staphylococcus aureus was investigated. The shape of the primary double reciprocal plots, the product inhibition pattern, and the features of the inhibition by a substrate analogue (acetone) show that diacetyl is reduced via an Ordered Bi-Bi mechanism, and 2,3-pentanedione by an Ordered Bi-Bi or Theorell-Chance mechanism. NADH is the leading substrate in both reactions. Affinity constants for the coenzyme and the substrates and inhibition constants for NAD, acetoin, and acetone were also calculated. This enzyme has a high affinity for NADH; Km (31-50 microM) and Ks (20-27 microM) for this compound are around one-tenth of the NADH intracellular concentration. Therefore, it must operate in vivo saturated with the coenzyme. This condition is not adequate to play the role, formerly proposed for diacetyl reductases, of regulating the equilibrium between oxidized and reduced forms of pyridine-nucleotides.

Acetoin Dehydrogenase↗