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L Olson

Publications and source records attributed to L Olson.

At least 397 records · Page 22Linked to original sources
PubMed1983

Enkephalin-like immunofluorescence in nerves of the rat iris following systemic capsaicin injection.

A network of nerve fibers with an enkephalin-like immunoreactivity was demonstrated in rat iris whole mounts. Systemic administration of capsaicin in doses which caused partial (5 mg/kg) or complete (50 mg/kg) disappearance of substance P-containing fibers in the iris did not cause degeneration of enkephalin-positive nerve fibers. The enkephalin-immunoreactive network seemed intact also after a capsaicin dose of 250 mg/kg. In fact, the fluorescence intensity of the nerve fibers showing enkephalin-immunoreactivity was often increased three days after a capsaicin injection in a dose of 50 mg/kg. The mechanism behind this effect of capsaicin remains to be elucidated, but could be due either to a direct effect on the enkephalin-positive nerves or involve the disappearance of substance P nerves and/or a simultaneous inflammatory response. However, an increased fluorescence intensity of the enkephalin-immunoreactive fibers was sometimes seen also without capsaicin treatment.

Animals↗
PubMed1983

Localization of nerve growth factor-like immunoreactivity in rat nervous tissue.

The use of immunofluorescence with affinity-purified antibodies enabled cytological localization of nerve growth factor-like material in the rat. Immunoreactivity was observed along various nerve tracts of the foetal rat brain and spinal cord at day 15 of gestation. Longitudinal pathways in ventral and dorsal spinal cord, ventral lower brain stem, posterior commissure, retroflex fascicle and in the olfactory bulb were all positive. A weaker and more widely spread immunostaining was visible in many areas in the central nervous system. Cranial nerves were strongly immunoreactive. Neuronal perikarya in the retina and the olfactory mucosa as well as filae olfactoriae and the olfactory nerve all the way to the olfactory bulb were also positive. In sensory ganglia and peripheral nerves most immunoreactivity was confined to supporting tissues, probably including Schwann cells. In irides, the pattern of immunoreactivity was similar to that of the sensory and autonomic innervation. More intensively fluorescent material was found in regrowing nerve fibres in iris transplants. Our histochemical results suggest that nerve growth factor and/or a related protein is present in large amounts along nerve pathways in supportive tissues of the peripheral nervous system as well as in the central nervous system during early development.

Animals↗
PubMed1983

Cerebellar Purkinje neuron hypoexcitability induced by chronic perinatal lead exposure.

The effects of perinatal lead administration on developing rat brain were studied by using cerebellar grafts in oculo. With 1% lead acetate in the drinking water, little change was seen in the histological organization of the graft. In marked contrast, virtually all Purkinje cell spontaneous discharge was absent in these grafts. This was seen even though 4-5 months had elapsed between the recording and the cessation of lead treatment. There was no alteration in electrophysiological properties of transplant Purkinje cells from sodium acetate-treated animals. Moreover, host in situ cerebellar Purkinje cells in both groups of animals discharged normally. These data indicate that lead administration, to elicit blood levels of 450-550 micrograms/liter, produces a long-lasting selective electrophysiological deficit in developing brain in oculo.

Action Potentials↗
PubMed1982

Transcriptional 'enhancers' from SV40 and polyoma virus show a cell type preference.

Transcriptional "enhancers" have been identified in both the monkey virus SV40 and in the mouse polyoma virus. Here we report that these enhancers show a cell type preference. This was done, (i) by assaying for T antigen expression and viral DNA replication of polyoma DNA which contains its own enhancer or the enhancer of SV40 virus, and (ii) by linking either of the two enhancer elements to the rabbit beta 1-globin gene and measuring transient globin expression in mouse and primate cells. The results were consistent in all the assays: In mouse cells the polyoma enhancer is slightly more effective than the SV40 enhancer. However, in primate cells the SV40 enhancer induces a four to six fold higher level of gene expression than does the polyoma enhancer.

Animals↗
PubMed1982

Selective early loss of polypeptides in liver microsomes of CCl4-treated rats. Relationship to cytochrome P-450 content.

Treatment of rats with carbon tetrachloride (CCl4) resulted in early reproducible losses of either one or two specific polypeptides (depending on the inducing agent with which the animals had been treated) in the molecular weight range of the multiple forms of cytochrome P-450. The loss was correlated with a decrease in total cytochrome P-450 content in the microsome. The results of this study and those in the accompanying report indicate that CCl4 was metabolized by a specific form of cytochrome P-450 (52,000 daltons), which was rapidly destroyed in the process. The early loss of this peptide occurred simultaneously with the previously demonstrated production of highly reactive trichloromethyl radicals (CCl3). This polypeptide, which was shown to disappear from liver microsomes following treatment of rats with CCl4 was demonstrated in the accompanying report to be the form of cytochrome P-450 specifically required for production of the highly reactive trichloromethyl radical in a reconstituted monooxygenase system.

Animals↗
PubMed1982

Specificity of a phenobarbital-induced cytochrome P-450 for metabolism of carbon tetrachloride to the trichloromethyl radical.

Evidence is presented which demonstrates that the first polypeptide to disappear in liver microsomes of phenobarbital-induced rats treated with CC14 was the 52,000 dalton p-450 cytochrome. Data are also presented which show that this form of cytochrome P-450 was capable of generating the trichloromethyl radical from CCl4 in a reconstituted system containing the purified cytochrome, NADPH-cytochrome P-450 reductase, NADPH, CCl4, and the spin-trapping agent, phenyl-t-butyl nitrone. Other cytochrome P-450 fractions not containing the 52,000 dalton form did not produce this radical. The formation of this highly reactive radical may have resulted in localized damage to the cytochrome, causing the cytochrome either to be released from the microsomal membrane or to form large aggregates which did not migrate in the gel electrophoretic procedures employed.

Animals↗
PubMed1982

A method for large-scale, high-yield isolation of canine pancreatic islets of Langerhans.

A modified collagenase digestion method is described for the isolation of large numbers of islets from the canine pancreas (approximately 3,500 islets/g). The islets isolated by this technique remained viable and released insulin in response to secretagogues after one week of maintenance in tissue culture. Islets isolated from a single donor pancreas were re-implanted into the spleen of the same animal made diabetic by subtotal pancreatectomy and two injections fo streptozotocin. Hyperglycemia was corrected in two dogs and decreased in a third dog followed for 30 days. The islet isolation method is described, therefore, provides a sufficiently large yield of viable islets from one donor pancreas to correct or improve diabetes in a recipient animal.

1-Methyl-3-isobutylxanthine↗
PubMed1982

Cellular and subcellular localization of protein I in the peripheral nervous system.

The cellular and subcellular distribution of protein I, a major brain phosphoprotein, has been studied in the peripheral nervous system. The levels of protein I in various peripheral nerves and innervated peripheral tissues were determined by radioimmunoassay and radioimmunolabeling of polyacrylamide gels. The results indicated tha protein I is present throughout the peripheral nervous system. Denervation studies of adrenal medulla and iris suggested that the protein I contained in peripheral tissues is localized to the neuronal elements innervating those tissues. Protein I was found to be enriched in neurotransmitter vesicle fractions of peripheral nervous tissue. Moreover, protein I appeared to be transported from cell bodies to axons terminals at least partly in association with neurotransmitter vesicles.

Adrenal Glands↗
PubMed1982

Studies on the survival of simultaneous canine renal and segmental pancreatic allografts.

Prolonged survival of the vascularized free-draining intraperitoneal pancreatic segmental allografts (FDPS) has been observed previously in immunosuppressed beagle littermates matched for low mixed lymphocyte culture (MLC) reactivity. When rejection (hyperglycemia) did occur, it was abrupt, unpredictable, and irreversible. This contrasts with renal allograft rejection in which elevations of serum creatinine are reversible with increased immunosuppression. In the present experiments, low MLC-reactive littermate pairs underwent simultaneous transplantation of kidney and FDPS allografts from the same donor. Increases in serum creatinine from 0.5 mg/dl to 1.5 mg/dl (renal rejection) occurred 4 to 5 days after transplantation (mean = 20.5 +/- 4.1) and preceded the onset of hyperglycemia by 6 to 22 days (mean = 1.06 +/- 4.6) in nonimmunosuppressed animals. At the onset of kidney rejection but before hyperglycemia developed, renal allograft biopsies revealed generalized mononuclear infiltration, while FDPS biopsies showed diffuse interstitial infiltration, but islets of Langerhans appeared to be spared. Treatment intervention with azathioprine and corticosteroids at the time of creatinine elevation prevented the onset of hyperglycemia from 46 to greater than 260 days in four of nine animals. Biopsies after 2 weeks of therapy showed resolution of the lymphoid infiltrates in the kidney and limitation of infiltrates to perivascular areas in the FDPS allografts. Immunological monitoring of peripheral blood lymphocyte function demonstrated the development of positive in vitro cell-mediated lymphocytoxicity shortly before the onset of hyperglycemia but only after creatinine elevation was well established and biopsies revealed evidence of rejection in both the renal and FDPS allografts.

Animals↗
PubMed1982

Intraocular development and adrenergic innervation of cortical and subcortical brain areas: influence of thyroid hormone deficiency.

Various immature brain regions have been isolated by grafting to the anterior chamber of the eye of adult recipients. The role of thyroid hormones for the growth of these isolated brain areas as well as their morphological maturation and adrenergic innervation in the eye have been investigated by surgical thyroidectomy of adult recipients prior to the intraocular brain grafting. Cortex cerebri showed a donor stage correlated thyroid hormone dependency so that 18-day donor fetuses gave rise to larger cortex grafts, whereas full-term donor fetuses resulted in smaller cortex grafts in thyroidectomized hosts. Brain stem showed an overall enhanced intraocular growth in thyroidectomized recipients, whereas both cerebellum and hippocampus did not seem to be influenced in oculo by a thyroid hormone deficiency. The morphological maturation of cortex cerebri grafts showed no alterations in thyroidectomized hosts as judged from light microscopy and cresyl violet staining. The density of sympathetic adrenergic nerves innervating the cortex cerebri grafts from the host iris was reduced by 50% in thyroidectomized hosts. This was parallelled by a reduction in noradrenaline concentration in cortex cerebri grafts in the experimental groups. Thus, the reduced number of nerves visible with Falck-Hillarp histochemistry in cortex cerebri grafts during thyroid hormone deficiency probably corresponds to a true reduction in adrenergic innervation. The present report points to a number of regionally as well as temporally selective effects on brain maturation and neuronal interaction of severe thyroid hormone deficiency.

Animals↗
PubMed1982

Effects of histocompatibility testing versus immunoreactive predisposition on kidney transplant survival.

From January 1979 to August 1981, 76 primary renal transplants were performed at the University of Miami-Jackson Memorial Hospital. Fifty-five of these were from living, related (LR) donors and 21 were from cadaver (CAD) donors. Histocompatibility typing for HLA-A, -B, and -DR antigens and of mixed lymphocyte culture (MLC) were performed. In LR patients the ability to generate donor-specific and nonspecific suppressor cells in vitro was tested preoperatively. Serial posttransplant immunologic monitoring was used in all patients by determining total T-cell numbers (E rosette-forming cells) as well as helper and suppressor T-cell subsets by use of monoclonal antibodies. Overall patient and graft survival was 90% and 87%, respectively. In this study MLC reactivity did not correlate with DR typing in CAD recipients, most of whom had marked reaction despite one or two DR antigen matches. Graft survival was also independent of MLC reactivity in both LR and CAD patients. The ability of LR recipients to generate donor-specific suppressor cells in vitro before transplantation did correlate significantly with absence of rejection episodes. Immunologic monitoring with T-cell subsets had prognostic significance for the detection of patients with excessive immunosuppression and high risk for development of infection (P less than 0.001). Thus, the responder status of many transplant recipients seemed as important as the current assessment of histocompatibility in influencing graft survival.

Antibodies↗
PubMed1982

Prenatal ontogeny of neurons with enkephalin-like immunoreactivity in the rat central nervous system: an immunohistochemical mapping investigation.

Immunohistochemical techniques were used to describe the presence of endogenous levels of enkephalin-like immunoreactivity (ELI) in the developing central nervous system of the rat up until birth. The appearance and prenatal ontogeny of nerve cell bodies, nerve fiber pathways and varicose terminal plexuses expressing ELI were thus mapped using the indirect fluorescence immunohistochemical technique and fluorescein- and rhodamine-conjugated second antisera. ELI was first observed in beaded fibers along the midline from ventral pons to cervical spinal cord by prenatal day 15. Fluorescence could not be observed in the brains of 14 day old fetuses, although the adrenal medulla did show ELI at this stage. ELI-positive cell bodies at prenatal day 18 were found in most areas in which they have previously been described in adult rats. Many of the cells observed at prenatal day 18 were, however, not seen in untreated full term fetuses with the techniques used here. ELI-positive fibers and terminal fields begin to approach adult distributions at prenatal day 21--22. Several ELI-positive axon pathways which have not been previously reported from adult or developing brain, such as e.g. pathways in medial neocortex, in fasciculus retroflexus, in tractus mammillothalamicus, between ventral hypothalamus and globus pallidus and between ventromedial pons and the locus coeruleus area, are described. Semischematic maps are presented which outline all ELI-positive material as seen in sagittal projections of the central nervous system of 15 day, 18 day and full term fetuses. Maps of representative transverse sections of the full term brain are also included.

Animals↗
PubMed1982

Differential ethanol sensitivity of intraocular cerebellar grafts in long-sleep and short-sleep mice.

The relative importance of extrinsic and intrinsic factors for the differential sensitivity of Purkinje neurons in long-sleep (LS) and short-sleep (SS) lines of mice was investigated using cerebellar grafts to the anterior chamber of the eye. Cerebellar anlagen from fetal LS and SS donors survive and mature in oculo when grafted within and across lines. Mature cerebellar transplants from all four groups contained Purkinje cells that show sustained spontaneous discharge; excitation and inhibition are readily evoked by electrical stimulation of the surface of the graft. Superfusion of ethanol into the anterior chamber depresses Purkinje cell discharge, but neurons from LS donors are approximately 1 order of magnitude more sensitive than SS neurons; this differential sensitivity is unaltered by the host recipient line used. These data strongly suggest that the differential sensitivity of Purkinje cells to ethanol in the LS and SS mouse lines is an intrinsic property of the cerebellum.

Action Potentials↗
PubMed1981

Factors regulating growth of catecholamine-containing nerves, as revealed by transplantation and explantation studies.

Intraocular grafting of various types of neuron and target tissue shows that peripheral and central noradrenergic neurons may substitute morphologically and functionally for each other in certain, but not all, target tissues. The morphology of growing adrenergic nerve terminals, their patterning, and the number of fibres are completely determined by the target tissues. Thus, the sympathetic adrenergic neuron of an adult organism is a highly plastic unit which may, for instance, double or even triple its terminal field in response to new demands from the environment. Several differences exist between central and peripheral adrenergic nerves: locus coeruleus will not innervate heart grafts; sympathetic fibres will not innervate the spinal cord; and central adrenergic neurons are not sensitive to nerve growth factor (NGF). Chromaffin cells can be made to innervate peripheral and central targets. No NGF is detected in normal adult iris. The iris responds to grafting, explantation, and to sensory or sympathetic denervation with rapid production of NGF as shown by bioassays on chick embryonic ganglia. This iris also contains a potent stimulatory factor for the ciliary ganglion. Trauma to the iris or to the anterior eye chamber may cause it to become hyperinnervated. Heavy metals have characteristic and different effects on the sympathetic nerves of the iris: lead and manganese causes hyperinnervation; cadmium does not change the number of nerves; while mercury causes severe terminal degeneration followed by regeneration.

Animals↗