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C Hanson

Publications and source records attributed to C Hanson.

At least 91 records · Page 5Linked to original sources
PubMed1990

Genes for C4b-binding protein alpha- and beta-chains (C4BPA and C4BPB) are located on chromosome 1, band 1q32, in humans and on chromosome 13 in rats.

C4b-binding protein is involved in the regulation of the complement system. It is a multimeric protein composed of seven identical alpha-chains and a single copy of a unique beta-chain. The latter was identified only recently and its structure determined by cDNA cloning. Both subunits in C4b-binding protein belong to the same superfamily of proteins composed predominantly of tandemly arranged short consensus repeats (SCR) approximately 60 amino acid residues in length. The gene for the human alpha-chain is known to be located in a gene cluster on chromosome 1, band 1q32, which is called the regulators of complement activation (RCA) gene cluster. We have used cDNA probes for both alpha- and beta-chains of human C4b-binding protein to localize their genes with an in situ hybridization technique. We find the genes for both chains to be located on chromosome 1, band 1q32, in the human. This suggests that the beta-chain gene is also a member of the RCA gene cluster and that the alpha- and beta-chain genes are located close to each other. The cDNA probes for the alpha- and beta-chains also were used to screen mouse-rat somatic cell hybrids using Southern blotting to localize their genes in the rat. Both the alpha- and beta-chain genes were shown to be located on chromosome 13 in the rat. These are the second and third genes to be located on rat chromosome 13, and the results suggest that the genes for the alpha- and beta-chains together with the gene for coagulation factor V represent a conserved chromosomal region in rat and man.

Animals↗
PubMed1990

High prevalence of HTLV-II among intravenous drug abusers: PCR confirmation and typing.

The polymerase chain reaction (PCR) was used to confirm the presence of human T-cell lymphotropic viruses (HTLV) in intravenous drug users (IVDU) whose sera were reactive by immunofluorescence assay (IFA) for HTLV-1/-II antibody. Peripheral blood mononuclear cells from 41 IFA-positive and 19 IFA-negative individuals were analyzed. HTLV sequences were detected in 39/41 IFA-positive samples; 36 were HTLV-II positive and 3 were HTLV-I positive. Two IFA antibody-positives were negative by both PCR and by enzyme immunoassay (EIA). One IFA and EIA antibody-negative sample was positive for HTLV-II by PCR. This study indicates a high prevalence of HTLV-II among IVDUs and further demonstrates the feasibility of using PCR to differentiate between HTLV-I and -II.

Fluorescent Antibody Technique↗
PubMed1990

Assignment of two rat dihydrofolate (DHFR) genes to chromosomes 2 and 4.

A panel of rat x mouse cell hybrids was used in the chromosomal mapping of the rat dihydrofolate reductase (DHFR) gene. It was determined that the probe hybridized to gene sequences on two different chromosomes (Nos. 2 and 4), possibly representing the active gene and a pseudogene. Hybridization of the DHFR probe to DNA from a methotrexate resistant rat cell line revealed that the gene on chromosome 2 was amplified, but not the gene on chromosome 4. This result was taken to suggest that the active DHFR gene is located on rat chromosome 2 and that the sequence on chromosome 4 is a pseudogene.

Animals↗
PubMed1990

Desensitization of beta-receptor mediated responses to epinephrine in fetal lambs by prolonged ritodrine administration.

During prolonged administration of beta-agonists such as ritodrine directly to chronically cannulated fetal lambs, the cardiovascular, metabolic, and endocrine changes observed during the 1st day of administration, lessen and return to normal within 3-4 d despite continuing drug administration. In our investigation, heart rate, plasma FFA, lactate, glucose, and insulin concentrations all increased significantly during the 1st day of ritodrine infusion (10 micrograms/min), whereas blood PO2 and base excess were significantly decreased. After 3 d, despite continued drug infusion, all these changes had ameliorated. To examine the hypothesis that this tachyphylaxis to ritodrine also results in decreased sensitivity to endogenous catecholamines, epinephrine (1 microgram/min i.v. for 60 min, then 2 micrograms/min i.v. for a further 60 min) was infused into fetal lambs (124-130 d gestation) 1 d before, then 5 +/- 1 d after, and again 10 +/- 1 d after beginning ritodrine infusion. Before ritodrine administration, epinephrine significantly increased plasma FFA, lactate, glucose, and glucagon concentrations and decreased insulin. However, after ritodrine treatment for either 5 +/- 1 or 10 +/- 1 d, epinephrine resulted in no significant increases in FFA or glucagon, and those in lactate and glucose were significantly reduced. Decreases in insulin during epinephrine administration were unchanged by ritodrine. Initial responses of mean arterial pressure and heart rate to epinephrine were significantly greater during prolonged ritodrine treatment. Fetal responses to epinephrine mediated through beta-adrenergic receptor mechanisms were clearly decreased when administration of beta-agonists was prolonged beyond 24 h.

Animals↗
PubMed1989

On the representation of events: a study of orientation, recall, and recognition.

Examined the representation of real-world events in memory as a function of orientation toward a videotaped sequence in which 2 people play a board game. In 4 experiments, analyzed subjects' segmentation of the videotaped sequence into events, using a technique developed by Newtson (1973). A comparison of segmentation patterns with performance on recognition, recall, and cued-recall tasks indicated that recall of events changed as a function of subjects' orientation toward the videotape, whereas recognition of events did not. The authors conclude that orientation toward an episodic sequence affects how rather than what events are represented in memory. An account of how orientation might affect the encoding and the representation of events is offered.

Adult↗
PubMed1989

Provirus insertion in Tpl-1, an Ets-1-related oncogene, is associated with tumor progression in Moloney murine leukemia virus-induced rat thymic lymphomas.

T-cell lymphomas induced in rats by Moloney murine leukemia virus acquire increasing numbers of proviruses in their genome during tumor progression in vivo and passage of tumor cells in vitro. To determine whether the proviruses progressively acquired during tumor progression play a causal role in this process, we cloned one of them from a cell line derived from the primary tumor 2772. A probe from the cellular DNA flanking the provirus was used to analyze 79 DNA samples from primary tumor tissues of 28 tumor-bearing rats and 80 DNA samples from 30 independent tumor cell lines. This analysis revealed a rearrangement in this region in the primary tumor derived from the thymus of one animal but not in a clone of the same tumor segregating in the spleen. Of the cell line DNA samples, three carried a provirus in this region. Two of these integration events had occurred independently in two clonally related sublines derived from tumor 2772, and they were followed by rapid selection in culture. On the basis of these findings this locus was named Tpl-1 (tumor progression locus 1). The Tpl-1 locus was mapped to rat chromosome 8 and to mouse chromosome 9 at a genetic distance of 1.2 +/- 0.9 centimorgans from the Ets-1 protooncogene. Although the genetic distance between Tpl-1 and Ets-1 indicates that they are different genes, analysis of Tpl-1 cDNA clones revealed that the two are closely related.

Animals↗
PubMed1989

Effects of altered photoperiod or maternal melatonin administration on plasma prolactin concentrations in fetal lambs.

During winter (December to March), when late-pregnant ewes were maintained under an artificial long-day photoperiod (16 h light) for 3 weeks or more before insertion of fetal vascular cannulae between 118 and 120 days of gestation (full term, 147 days), plasma prolactin concentrations in their fetal lambs were significantly increased throughout the last 3 weeks of gestation in comparison with values in similar aged fetuses from ewes experiencing only the natural short-day (less than 9 h light) winter photoperiod. When additional lighting was given only after vascular cannulation, fetal plasma prolactin increased steadily from low values, characteristic of winter pregnancies, to high values, characteristic of long-day (16 h light:8 h darkness) pregnancies. Maternal plasma prolactin concentrations changed in a similar way. During summer pregnancies (greater than 16 h light), plasma prolactin in fetal lambs was significantly reduced within 48 h when ewes were given melatonin by i.v. infusion for 14 h each night to simulate the winter duration of the nocturnal increase in plasma melatonin. Maternal plasma prolactin concentrations also decreased significantly when melatonin was given for 3 weeks, but not in a shorter experiment. Increases in fetal plasma prolactin were proportional to the basal prolactin concentration in fetuses injected i.v. with TRH or a dopaminergic antagonist, metoclopramide, to assess how photoperiod influenced the responsiveness of prolactin secretion to acute stimulation. The results confirm that photoperiod, rather than developmental maturity, is the principal determinant of plasma prolactin in the fetal lamb during the last third of gestation, and provide evidence that photoperiodic information is transmitted to the fetus through the diurnal rhythm of melatonin in the ewe.

Animals↗
PubMed1989

Metabolic and cardiovascular changes during prolonged ritodrine infusion in fetal lambs.

Prophylaxis of threatened premature labor with ritodrine may lead to prolonged fetal exposure to the drug. To investigate the direct consequences of this, 11 fetal lambs were given ritodrine hydrochloride for periods of 2-4 days by continuous intravenous infusion at 5 or 10 micrograms/minute (1-3 micrograms/minute/kg estimated fetal weight). These dosages had no measurable effects on the ewes. In the fetus, measurements confirmed and extended the results of earlier short-term experiments, but differences from the effects of long-term maternal ritodrine infusion imply little placental transfer of the drug in sheep. Ritodrine had little or no effect on mean arterial pressure, blood pH, pCO2, plasma alpha-amino acid nitrogen, or growth hormone, but resulted in marked hypoxemia, tachycardia, hyperlactacidemia, hyperglycemia, and hyperinsulinemia during the first 24-48 hours of infusion. Despite continued ritodrine infusion, heart rate and the metabolic parameters returned toward normal within 72 hours. Hypoxemia persisted longer, but tended to lessen after 2 days of infusion. The results indicate that tachyphylaxis to ritodrine develops in the fetal lamb during prolonged administration, but that when fetal well-being is already compromised, ritodrine's effects on oxygenation and lactacidemia could jeopardize fetal survival.

Animals↗
PubMed1989

Identification of a cellular polypeptide that distinguishes between acute lymphoblastic leukemia in infants and in older children.

We analyzed the polypeptide pattern of leukemic cells of infants and older children with acute lymphoblastic leukemia (ALL), using two-dimensional polyacrylamide gel electrophoresis (PAGE). Patterns were analyzed for the occurrence of a previously detected cytosolic polypeptide, designated L3. Quantitative analysis of L3 in 12 infants and 91 older children with non-T ALL indicated lack of expression of polypeptide L3 in leukemic cells of infants which, in most cases, expressed HLA-DR and CD19 and lacked CD10. Quantitative analysis of L3 in relation to cell surface marker expression revealed that L3 was limited in its occurrence to non-T ALL and was not coordinately expressed with any of the surface markers included in the study. Among patients in the HLA-DR-positive, CD19-positive, and CD10-negative group, different levels of polypeptide L3 were observed between infants and older children. These results indicate differences in leukemic cell constituents between infants and older children with ALL and an otherwise similar cell surface marker phenotype.

Adolescent↗
PubMed1988

Frequency encoding of token and type information.

Two experiments examined how attention to stimulus attributes affects knowledge of frequency of occurrence. In Experiment 1, orienting tasks were used to direct subjects' attention to either the category membership or the initial letters of words. In Experiment 2, subjects' attention to words, category membership, and initial letters was directed with explicit instructions. The results of these two experiments suggest that attention to specific stimulus attributes may be necessary to initiate the encoding of frequency information. We discuss the implications of these results for claims that the encoding of frequency of occurrence is automatic.

Attention↗
PubMed1988

Renin in human fetal lung--a biochemical and immunohistochemical study.

Human fetal lung homogenates contain an inactive form of renin which may be revealed by trypsin treatment. When activated, this form of renin has some biochemical similarities with fetal kidney renin: the pH optimum of fetal lung renin is approximately 6.5; it is bound by Affigel Blue affinity chromatography resin; and is inhibited by a monoclonal antibody (R-3-36-16) raised to human kidney renin. Inactive renin, partially-purified from both fetal kidney and lung, differs from this in that the renal form is of low-molecular weight (LMW, 45,000 daltons), whereas that from fetal lung is of high molecular weight (HMW, 58,000 daltons). Using a sensitive alkaline phosphatase-anti-alkaline phosphatase (APAAP) procedure with a polyclonal anti-renin antibody (R-15), immunoreactive renin in fetal lung was found in vessels in mesenchyme between airways. The pattern of staining was distributed similarly to Factor VIII-related antigen, suggesting localization in endothelial cells.

Fetus↗
PubMed1988

Renin in blood vessels in human pulmonary tumors. An immunohistochemical and biochemical study.

The authors have used a sensitive alkaline phosphatase-anti-alkaline-phosphatase immunohistochemical method to examine 28 human pulmonary carcinomas for the presence of renin. Immunoreactive renin was found in 23 (82%) cases. Specific staining was always associated with small vessels in the stroma of the tumor or in adjacent areas of inflamed fibrous tissue. Within vessels, renin was localized in the cytoplasm of medial cells. Adenocarcinoma exhibited the most consistent staining (11/12 cases), and this appeared to be independent of the degree of tumor differentiation. Immunoreactive renin was also detected in squamous cell (7/8 cases), undifferentiated large cell (4/4 cases), and small cell undifferentiated carcinoma (1/1 cases), but the number of vessels and intensity of staining were usually less than seen in adenocarcinoma. Staining was not found in the bronchioloalveolar variant of adenocarcinoma (0/3 cases). By means of immunoaffinity chromatography with monoclonal antibodies (MAbs) raised to kidney renin, both active and inactive renin were extracted from homogenates of surgical specimens. The molecular weight of both forms of renin was approximately 59,000 daltons.

Adenocarcinoma↗
PubMed1987

Impaired forearm vasodilator reserve in patients with microvascular angina. Evidence of a generalized disorder of vascular function?

In previous work, we described a group of patients with angina-like chest pain and normal coronary arteries. These patients had impaired coronary vasodilator responses to the stress of rapid atrial pacing and to the administration of dipyridamole, a potent vasodilator of coronary arterioles. This abnormality appears to be localized to the prearteriolar microvascular bed. To determine whether these patients have a more generalized abnormality of vasodilator reserve, we used mercury-in-Silastic strain-gauge plethysmography to compare their hyperemic responses to forearm ischemia with those of normal controls. After 10 minutes of ischemia, peak forearm flow was 39.9 +/- 5.0 ml per minute per deciliter in the controls [corrected] and 31.7 +/- 10.5 in the patients [corrected] (21 percent reduction; 95 percent confidence interval, 4 percent to 37 percent). Flow responses were also significantly reduced after three and five minutes of ischemia. Correspondingly, the vascular resistance after ischemia was also consistently higher in the patients with microvascular angina. The degree of vasodilator impairment in the peripheral circulation correlated well with the degree of vasodilator impairment in the coronary circulation (r = 0.74; P less than 0.004). Thus, patients with microvascular angina appear to have an impairment of vasodilator reserve that affects not only their coronary circulation but also their peripheral arterial bed.

Adult↗
PubMed1987

Novel cytogenetic expression of gene amplification in actinomycin D-resistant somatic cell hybrids: transfer of resistance by centric chromatin bodies.

SEWATC13 mouse cells, resistant to 0.1 microgram/ml of actinomycin D (AMD), were fused to AMD-sensitive cells of the Chinese hamster ovary cell line (CHO). Twenty-two hybrid clones were isolated and put into serial culture in the selective medium. Unexpectedly, identifiable mouse chromosomes were found only in one of the hybrids. All the others had only hamster chromosomes and, in addition, numerous chromatin bodies (CBs), mostly small and irregularly shaped, but also larger, more chromosome-like ones. The CBs were distinctly C-band positive and a mouse satellite probe hybridized strongly to them. The AMD resistance of the murine parental cells had previously been attributed to gene amplification in two large homogeneously staining regions (HSR-AMD1 and 2). They were not observed in the hybrid cells but had supposedly reappeared in the guise of the CBs. It was established by Southern DNA blot analysis that amplified DNA sequences, localized to the HSR-AMD1 and 2 of the SEWA parent were present in multiple copies in the hybrids. It was also established by in situ hybridization that they were located in the CBs. Unlike double minutes (DMs) the CBs were all centric.

Animals↗
PubMed1987

Renal function during bovine neurotensin infusion in man.

The peptide hormone neurotensin (NT) is found mainly in gut endocrine cells of the ileum, but has also been identified as a putative neurotransmitter in the central and peripheral nervous systems. It may have a dual role as a circulating gastrointestinal hormone and peripheral neurotransmitter. Its predominant effects are to reduce oesophageal sphincter tone, inhibit gastric secretion and emptying and inhibit intestinal motility, but stimulate intestinal and pancreatic exocrine secretion; NT-like immunoreactivity has been found in kidney and therefore NT may influence renal function. When infused i.v. in rabbits it causes antinatriuresis. We have studied its renal effects in 11 healthy males by i.v. infusion under conditions of altered dietary sodium. Postprandial circulating neurotensin levels were reproduced by infusion. There were no consistent systemic or renal haemodynamic effects. Plasma electrolytes and renin did not change. Only renal chloride excretion changed significantly, falling by ca. 30%, and recovering after infusion. There is no evidence for a specific renal tubular chloride transport mechanism, but coupled cotransport, Na+:K+:2CI-, may be hormonally regulated. NT might stimulate this process and contribute to the renal response to changes in dietary composition, especially sodium intake.

Adult↗