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Biomedical subjects

C Hansen

Publications and source records attributed to C Hansen.

At least 163 records · Page 9Linked to original sources
PubMed1988

Changed composition of high-density lipoprotein subclasses HDL2 and HDL3 after renal transplantation.

The concentrations of cholesterol in the high density lipoprotein (HDL) fraction and the HDL2 and HDL3 subclasses were compared in 333 male renal transplant recipients, 36 male patients on maintenance hemodialysis, and 43 healthy men. The subclasses were separated by a precipitation method using polyethylene glycol 6000 and dextran sulphate. In hemodialyzed patients, total HDL cholesterol and both subclasses were reduced. In renal transplant recipients, both total HDL cholesterol and HDL2 were normal, whereas HDL3 remained reduced, analogous to hemodialyzed patients. It can be concluded that a successful renal transplantation has a beneficial effect on HDL metabolism and thus on the development of atherosclerosis.

Cholesterol, HDL↗
PubMed1988

Abnormal I-123 metaiodobenzylguanidine myocardial washout and distribution may reflect myocardial adrenergic derangement in patients with congestive cardiomyopathy.

I-123 metaiodobenzylguanidine (MIBG) is a new radiopharmaceutical with properties that allow the characterization of the sympathetic innervation of several organ systems. In this study, we used MIBG with tomographic imaging to evaluate noninvasively the differences in myocardial sympathetic innervation in 14 healthy volunteers and 16 patients with severe dilated cardiomyopathy (CM). Initial (15-minute) images demonstrated no significant differences in MIBG concentration in the hearts of patients with CM and of healthy volunteers. However, the myocardial retention of MIBG was significantly reduced in the patients with CM. Expressed as the percent washout from 15 to 85 minutes, the patients with CM had a 28 +/- 12% washout rate compared with 6 +/- 8% in the controls (p less than 0.001). A small subset of patients from each group imaged at 4-hour intervals demonstrated even greater disparity in washout rates. In addition, the patients with CM had significantly greater heterogeneity in the MIBG activity distribution within the myocardial images. There was 47 +/- 15% intraimage variability in MIBG distribution in the patients with CM and 22 +/- 9% variation in the controls (p less than 0.001). We conclude from these data that the myocardial distribution and kinetics of MIBG in images obtained from patients with CM differ significantly from those of controls and that the MIBG patterns may be used as a relatively noninvasive means to evaluate the severity of altered adrenergic innervation in the hearts of these patients.

3-Iodobenzylguanidine↗
PubMed1988

Cerebral blood flow during delirium tremens and related clinical states studied with xenon-133 inhalation tomography.

The regional cerebral blood flow of 12 patients with severe alcohol withdrawal reactions (delirium tremens or impending delirium tremens) was measured during the acute state before treatment and after recovery. Greater cerebral blood flow was significantly correlated with visual hallucinations and agitation during the acute withdrawal reaction. The results suggest that delirium tremens and related clinical states represent a type of acute brain syndrome mainly characterized by CNS hyperexcitability.

Adult↗
PubMed1988

Reversible impairment of glucose-induced insulin secretion in SHR/N-cp rats. Genetic model of type II diabetes.

The SHR/N-cp rat is a new genetically obese model for non-insulin-dependent diabetes mellitus. Expression of the diabetes is enhanced by a high-sucrose (54%) diet. After 4 wk on the diet, the cp/cp rats weigh significantly more than their +/? controls, have postprandial hyperglycemia (greater than 400 mg/dl), and are hyperinsulinemic, with immunoreactive insulin (IRI) levels 10- to 20-fold greater than controls. Total pancreatic IRI tends to be increased 1.6-fold in the cp/cp rats (although not significantly). There is no increase in pancreatic proinsulin content as a percent of total IRI. Studies of in vitro pancreatic function were carried out with the isolated nonrecirculating perfused pancreas method. The cp/cp rats (n = 10) showed impaired or absent IRI responses to 16.5 mM glucose, whereas +/? rats (n = 9) responded with classic biphasic curves. Comparison of insulin secreted in 20 min revealed a greater than 53% decrease in IRI secretion in cp/cp rats (P less than .05). A paradoxical hypersecretion of IRI at glucose concentrations of 0-2.7 mM was noted in cp/cp but not lean rats, i.e., 1.8 +/- 0.2 mU/min IRI in cp/cp rats vs. 0.04 +/- 0.007 mU/min in +/? rats. Perfusion of pancreases for 45 min with buffers containing no glucose resulted in restoration of a normal biphasic IRI response to 16.5 mM glucose in the cp/cp rats, whereas response in the lean rats was markedly reduced. Brisk IRI responses to 10 mM arginine in buffers with no glucose also occurred in cp/cp but not +/? rats. Glucagon secretion was relatively suppressed in the cp/cp rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Synergistic effects of the xid gene in X chromosome congenic mice. I. Inability of C3.CBA/N mice to respond to thymus-dependent antigens in adoptive transfer assays.

The xid gene, which causes a B lymphocyte immune defect in CBA/N mice, has been bred onto the C3H/HeN background. The resulting X chromosome congenic mice (C3.CBA/N) exhibit immunologic defects that are much more profound than the defect exhibited by CBA/N mice; thus, the B cells from C3.CBA/N mice not only fail to respond to thymus-independent (TI) type 2 antigens such as TNP-Ficoll, but they fail to respond in vitro to TI-type 1 antigens such as TNP-Brucella abortus (BA) and B cell mitogens such as LPS and Nocardia water-soluble mitogen. In this paper we show that the synergistic defect seen in C3.CBA/N B cells is also elicited in adoptive transfer assays to thymus-dependent (TD) antigens such as TNP-KLH and PC-KLH, antigens to which both parental strains respond. Thus, the secondary adoptive transfer response of C3.CBA/N spleen cells is generally less than 5% of the immune response produced by CBA/N or C3H/HeN spleen cells. This synergistic defect is restricted to the C3.CBA/N B cells, since C3.CBA/N T cells can provide help to CBA/N B cells that is equivalent to the help obtained with CBA/N T cells. The low responsiveness of C3.CBA/N spleen cells to TD antigens, which is elicited in adoptive transfer assays, is not seen when the intact animal is immunized with antigen in CFA; this, intact C3.CBA/N mice produce anti-PC-KLH and anti-TNP-KLH responses only slightly lower than the responses of CBA/N mice to these same antigens. In contrast, when these mice are immunized with phenol-extracted LPS, a TI-type 1 antigen, their antibody responses are severely depressed. These data suggest that under conditions in which T cell help may be limiting or in which the intact physiology of the T and B cells has been disrupted, C3.CBA/N B cells demonstrate profound immunologic impairment; however, when adequate T cell help is available and the splenic architecture is not disrupted, their immune responses appear to progress in a normal fashion.

Animals↗
PubMed1987

Preparation of single-stranded deoxyribonucleic acid probes using an immobilized template.

A new method for the easy preparation of specific single-stranded DNA fragments is presented. Recombinant M13 DNA containing the strand complementary to the sequence of interest is made partially double-stranded by elongating a conventional M13 sequencing primer. Following linearization by enzymatic digestion downstream from the insert (relative to priming site), this DNA is coupled to diazotized paper through its single-stranded (vector) portion. Subsequent denaturation of the double-stranded region generates an immobilized template strand. Successive runs of primed syntheses of the (desired) complementary strand can be realized using the same template. The copies are easily isolated by release upon denaturation. DNA probes prepared by this method have proven to be valuable tools for gene analysis.

DNA, Recombinant↗
PubMed1987

Normal and defective expression of the thyroglobulin gene.

Molecular studies of the thyroglobulin (Tg) gene have progressed significantly in recent years. Cloning and sequencing the complete bovine Tg cDNA led to the knowledge of the primary structure of the Tg subunit. This large polypeptidic chain displays a repetitive structure, especially in its amino-terminal half, and bears a striking homology with the acetylcholinesterase molecule of Torpedo californica in its carboxy-terminal portion. The four specific domains known to be involved in the formation of the thyroid hormones have been assigned to both terminal parts of the polypeptide, a location which could play a role in the process leading to hormone release. The very large (greater than 250 kb) Tg gene has been localized on the long arm of chromosome 8 in man, in close linkage with the c-myc oncogene. The study of its structure allowed the characterization of the molecular defect responsible for a congenital flaw in Tg gene expression in a herd of South-African cattle. This work led to the unexpected finding that the Tg pre-mRNA undergoes alternative splicing in normal animals, too. A DNA segment involved in the transcriptional control of Tg gene expression by cAMP has been identified by transfecting primary cultured thyrocytes with recombinant genes.

Animals↗
PubMed1987

Quantification of myocardial injury produced by temporary coronary artery occlusion and reflow with technetium-99m-pyrophosphate.

Previously, technetium-99m-stannous pyrophosphate (99mTc-PPi) has been used to localize and estimate the size of myocardial infarcts in animals after permanent coronary artery occlusion. This study tested the hypothesis that 99mTc-PPi accurately sizes myocardial infarctions produced by temporary coronary artery occlusion and reflow in dogs. Three groups of dogs were studied: group A underwent 3 hr of occlusion followed by 2 hr of reperfusion, with 99mTc-PPi injected 10 min after reflow (n = 10); group B underwent 3 hr of occlusion followed by 2 hr of reperfusion, with 99mTc-PPi injected 90 min after reflow (n = 11); and group C underwent 3 hr of occlusion followed by reflow with 99mTc-PPi injected at 10 min and again at 48 hr after reflow (n = 5). Myocardial slices from group A and B dogs were imaged in vitro. Group C dogs were imaged with single photon-emission computed tomography (SPECT) in vivo, and myocardial slices were imaged in vitro at the conclusion of the study. The extent of myocardial infarction was defined with triphenyltetrazolium chloride (TTC) staining, and coronary blood flow was estimated with radioactive microspheres. In addition, transmural myocardial tissue samples were taken from the center of the myocardial infarction, the lateral portion of the myocardial infarction, the normal myocardium adjacent to the lateral aspect of the infarcts, and from the normal myocardium and counted for 99mTc-PPi activity. A significant correlation was found between infarct size determined by areas of increased 99mTc-PPi uptake and that estimated from TTC staining for both group A (r = .89) and group B animals (r = .98).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Thymus-dependent and -independent regulation of Ia antigen expression in situ by cells in the synovium of rats with streptococcal cell wall-induced arthritis. Differences in site and intensity of expression in euthymic, athymic, and cyclosporin A-treated LEW and F344 rats.

Euthymic LEW rats, when injected with streptococcal cell walls, exhibited rapid onset development of acute exudative arthritis coincident with enhanced synovial expression of Ia antigen. By 21 d after injection, the expression of Ia was markedly increased compared with basal conditions and paralleled the severity of the later developing proliferative and erosive disease. Immunodeficient athymic and cyclosporin A-treated LEW rats developed only the early phase arthritis, which was again paralleled by synovial Ia expression. Chronic expression of high levels of Ia antigen was not observed. Histocompatible F344 rats, both athymic and euthymic, developed minimal, if any, clinically significant arthritis and did not exhibit the enhanced Ia expression demonstrated in the LEW rats. Our results indicate that enhanced synovial Ia expression parallels clinical disease severity and varies by rat strain, and that the rapid onset enhanced synovial Ia expression is thymus independent, whereas the markedly enhanced chronic phase Ia expression is thymus dependent.

Animals↗
PubMed1987

Control of thyroglobulin gene transcription by TSH and cAMP.

The availability of the sequence of Tg promoter from three different species enabled a fruitful comparison to be made from which a general picture of the organization of the Tg gene promoter region emerged. Chromatin structure studies identified tissue-specific modifications at the level of DNA protein interactions. A DNA element has been shown to be involved in transcription control by cAMP. This sequence includes a highly conserved region of the Tg gene promoter, overlaps a domain of the promoter which becomes hypersensitive to DNase I when the gene is expressed and displays specific protein-DNA interaction. These observations are consistent with the possibility that this sequence is a target element for trans-acting factor(s) which control(s) the transcriptional activity of the gene.

Animals↗
PubMed1986

Three morphologically distinct types of interface develop between adult host and fetal brain transplants: implications for scar formation in the adult central nervous system.

The development of the host/graft interface of cerebellar and cerebral transplants was studied 1-60 days after operation. Grafts from fetal Wistar rats were transplanted to a cavity over the superior colliculus of adult rats by removing parts of the overlying cortex and hippocampus according to the Björklund/Stenevi technique. In sham-operated control rats, in which a cavity was made in the brain but no graft was implanted, the parenchyma bordering the entire cavity developed a complete glial-meningeal scar within 2 weeks after operation consisting of multilayered glial processes, a basal lamina, and fibroblasts (meningeal cells). A similar interface also developed between graft and host in the most superficial parts of the transplantation cavity. In the basal parts of the transplantation cavity, the host/graft interface consisted either of an incomplete sheet of astrocyte processes aligned in parallel to each other but without a covering basal lamina or of completely fused neuropil without any morphological signs of separation between host and transplant. It is concluded that these three zones of host/graft interface are established by differential interaction between the growing transplant and the host cicatrix. At the basal host/graft parenchymatous interface the fetal transplant interferes with the normal adult cicatrization process of the host, possibly by either releasing inhibitory factors or by preventing contact between the astroglia of the host and fibroblasts (meningeal cells). In white matter regions of the transplantation cavity, voluminous cysts developed, both in sham-operated controls and in graft recipients, which were invaded by transplanted neurons.

Animals↗
PubMed1986

High antibody response to autologous type II collagen is restricted to H-2q.

The incidence of arthritis and the antibody response to mouse and to rat type II collagen after immunization with native rat type II collagen was studied in different mouse strains, including wild mouse-derived strains belonging to the H-2p/H-2q family. High serum levels of antibodies to mouse and rat type II collagen were seen only in H-2q mice, whereas mice belonging to the p, w3, w5, and w17 haplotypes displayed low type II collagen-specific antibody responses. Mice from three different H-2q-carrying strains (DBA/1, NFR/N, and B10.G) with different non-major histocompatibility complex genes were all susceptible to collagen arthritis, but they displayed a varying incidence of arthritis and varying clinical features. No arthritis was seen in non-H-2q mice, except in the B10.CAS2 strain where a few mice developed arthritis despite very low serum levels of type II collagen-specific antibodies. We conclude that small differences in the A beta chain of class II transplantation antigens are of importance for the development of arthritis and for the stimulation of a high response after immunization with type II collagen.

Animals↗
PubMed1986

[In vitro sensitivity of T lymphocytes to theophylline in healthy adults and patients following cadaver kidney allotransplantation].

In the peripheral blood of healthy adults the number of theophylline-resistant T-lymphocytes (T-res) is 51 +/- 4% and 1,161 +/- 326/microliter, respectively, and the number of theophyllins-sensitive 11 +/- 2% and 252 +/- 95/microliters. The membrane markers show a heterogeneous distribution. The quotient from T-res/T-sens is 4.9 +/- 1.3. Within the T-sens 14% are CD4+ and 30% CD8+, 29% carry Fc-IgC and 34% Fc-IgM-receptors. Thus the T-res in their netto-function were helper cells and the T-sens suppressor/cytotox cells. Before the transplantation the preoperative ratio of the two subpopulation is significantly diminished (Q = 3.66 +/- 1.53), however, prognostic statements cannot be deduced from this. Activations of the immune system (rejection crises, cytomegalovirus infections) are accompanied by significant diminutions of the T-sens, whereby the T-res/T-sens-Quotient increases. Thus they are unequivocally included into immunoregulatory processes.

Adolescent↗
PubMed1986

[Roentgen morphology following interventions of the lumbar intervertebral disk].

We compared x-ray films of 204 patients, evaluating plain radiographs, computer tomograms and myelographies. This study showed that plain radiographs serve as a guide, enabling to localise the level at which bone defects have occurred as a result of surgery. Conventional tomography is important for detecting changes associated with postoperative discitis. In about 50% of the patients, computed tomography enables satisfactory indication for a second intervention if used together with plain roentgenography and clinical examination. Myelography remains an indicated procedure if the disease pattern is not clear and if findings are ambivalent.

Humans↗
PubMed1985

A study on antisperm antibody in homosexual men.

Using a hemagglutination assay we surveyed antibody distribution to human sperm antigen in a sexually transmitted disease (STD) clinic population and in an AIDS study group. We found no significant difference for the mean antisperm antibody titres between sexually active heterosexual men, women or homosexual men, homosexual men with or without AIDS, and no correlation between T4/T8 lymphocyte ratios and antibody titres in homosexual men. We conclude that levels of antibody to sperm antigens are not significantly greater in homosexual men and antisperm antibody levels do not correlate with the diagnosis of AIDS.

Acquired Immunodeficiency Syndrome↗