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O Sorensen

Publications and source records attributed to O Sorensen.

At least 19 recordsLinked to original sources
PubMed1995

Combined therapy with interleukin-4 and interleukin-10 inhibits autoimmune diabetes recurrence in syngeneic islet-transplanted nonobese diabetic mice. Analysis of cytokine mRNA expression in the graft.

Syngeneic pancreatic islet grafts in nonobese diabetic (NOD) mice elicit a cell-mediated autoimmune response that destroys the insulin-producing beta cells in the islet graft. IL-4 and IL-10 are cytokines that inhibit cell-mediated immunity. In this study, we evaluated the effects of IL-4 and IL-10 on the survival of syngeneic pancreatic islets transplanted into diabetic NOD mice. Islet grafts survived beyond 18 days and normoglycemia was maintained in 67% (10 of 15) of mice treated with IL-4 plus IL-10, but in none (0 of 20) of vehicle-injected (control) mice. Also, 40% (6 of 15) of the mice treated with IL-4 plus IL-10 were normoglycemic at 30 days after transplantation, compared with 14% (1 of 7) of the mice treated with IL-4 alone, 8% (1 of 13) of the mice treated with IL-10 alone, and none (0 of 20) of the control mice. Histological examination of grafts at 10 days after transplantation revealed peri-islet accumulations of mononuclear leukocytes and intact islet beta cells in grafts from IL-4 plus IL-10-treated mice, whereas islets were infiltrated by leukocytes and the beta cell mass was greatly reduced in grafts from control mice. Polymerase chain reaction (PCR) analysis of cytokine mRNA expression in the grafts revealed higher levels of IL-2, IFN gamma, and IL-10 mRNA in grafts of diabetic compared with normoglycemic control mice, whereas IFN gamma and TNF alpha mRNA levels were significantly decreased in grafts of IL-4 plus IL-10-treated mice compared with either normoglycemic or diabetic control mice. These results suggest that T helper (Th)1 cells and their cytokine products (IL-2, IFN gamma, and TNF alpha) may promote islet beta cell destructive insulitis and autoimmune diabetes recurrence in syngeneic islet-transplanted NOD mice, and that administration of IL-4 plus IL-10 may inhibit diabetes recurrence by suppressing Th1 cytokine production in the islet grafts.

Animals↗
PubMed1995

IFN-gamma gene expression in pancreatic islet-infiltrating mononuclear cells correlates with autoimmune diabetes in nonobese diabetic mice.

Insulin-dependent diabetes mellitus in nonobese diabetic (NOD) mice results from selective destruction of pancreatic islet beta-cells following islet infiltration by mononuclear leukocytes. Cytokines produced by islet-infiltrating mononuclear cells may be involved in beta-cell destruction. Therefore, we analyzed cytokine mRNA expression, by reverse-transcriptase PCR (RT-PCR) assay, in mononuclear leukocytes isolated from pancreatic islets of four groups of mice: diabetes-prone female NOD mice; female NOD mice protected from diabetes by injection of CFA at an early age; male NOD mice with a low diabetes incidence; and female BALB/c mice that do not develop diabetes. We found that mRNA levels of IL-1 beta, IL-2, IL-4, IL-10, and IFN-gamma in mononuclear cells from islets of diabetes-prone female NOD mice increased progressively as these cells infiltrated the islets from age 5 wk to diabetes onset (> 13 wk). However, only IFN-gamma mRNA levels were significantly higher in islet mononuclear cells from 12-wk-old diabetes-prone female NOD mice than from less diabetes-prone NOD mice (CFA-treated females, and males) and normal mice (BALB/c). In contrast, IL-4 mRNA levels were lower in islet mononuclear cells from diabetes-prone female NOD mice than from NOD mice with low diabetes incidence (CFA-treated females and males). Splenic cell mRNA levels of IFN-gamma and IL-4 were not different in the four groups of mice. These results suggest that islet beta-cell destruction and diabetes in female NOD mice are dependent upon intra-islet IFN-gamma production by mononuclear cells, and that CFA-treated female NOD mice and male NOD mice may be protected from diabetes development by down-regulation of IFN-gamma production in the islets.

Aging↗
PubMed1994

Characterization of a granule-independent lytic mechanism used by CTL hybridomas.

The mechanism(s) by which CTL induce target cell lysis have not been clearly elucidated. Perforin and the cytotoxic cell proteinases (granzymes) contained within the granules of CTL and NK, have been implicated, but abundant evidence for the existence of alternate lytic pathways has accumulated. In this report we characterize the mechanism of killing used by two cytolytic hybridomas (PMM-1 and MD90) that express neither perforin nor the granzymes. These characteristics are compared with results obtained by using a representative Ag-dependent, granule-containing T cell clone in cytolysis assays. The major differences were that the granule-negative hybridomas could lyse a variety of target cells in the presence of cyclosporin and the absence of calcium. All the effectors could kill in the presence of protein synthesis inhibitors (cycloheximide and emetine) and induced DNA fragmentation in the target cells. The cytolytic hybridomas had to be stimulated to be cytolytic and this activation required the presence of calcium, was dependent on protein synthesis, and inhibited by the addition of cyclosporin. Although TNF was shown not be involved, the sensitivity of the target cells to lysis by the granule-negative killers correlated with the level of expression of Fas Ag. With the use of L1210 and an L1210 cell line transfected with Fas cDNA we demonstrated that these MD90 and PMM-1 kill the latter much more effectively and that this increase was effectively inhibited with anti-Fas Ab. Furthermore the lack of sensitivity to cyclosporin, cycloheximide, emetine, and EGTA was confirmed with these targets. We conclude that these two cytolytic hybridomas use the Fas lytic pathway to induce lysis in target cells.

Animals↗
PubMed1994

Analysis of cytokine mRNA expression in syngeneic islet grafts of NOD mice: interleukin 2 and interferon gamma mRNA expression correlate with graft rejection and interleukin 10 with graft survival.

The injection of complete Freund's adjuvant into diabetic nonobese diabetic (NOD) mice at the time of syngeneic islet transplantation prevents monocytic/lymphocytic cell infiltration into the islet graft, Beta-cell destruction, and autoimmune diabetes recurrence. We have used semiquantitative reverse transcriptase-polymerase chain reaction analysis to examine and compare cytokine mRNA expression profiles in islet grafts from complete Freund's adjuvant-injected and control NOD mice. Interleukin 10 mRNA expression was significantly increased whereas interleukin 2 and interferon gamma mRNA levels were significantly decreased in islet grafts from complete Freund's adjuvant-injected mice compared to control mice. Levels of mRNA for interleukin 1 beta, interleukin 4, and tumour necrosis factor alpha were not significantly different in islet grafts from complete Freund's adjuvant-injected and control mice. These findings suggest that a Th1 subset of lymphocytes and their cytokine products, interleukin 2 and interferon gamma, may be involved in the rejection of syngeneic islet grafts and diabetes recurrence in NOD mice, and that the protective effect of complete Freund's adjuvant may result from the induction of interleukin 10 production and consequent down-regulation of Th1 cells and cytokines in the islet graft.

Animals↗
PubMed1991

Effects of hypothyroidism and high-fat feeding on mRNA concentrations for the low-density-lipoprotein receptor and on acyl-CoA:cholesterol acyltransferase activities in rat liver.

1. Induction of hypothyroidism in rats by feeding propylthiouracil (PTU) significantly increased serum cholesterol concentrations, and the effect was more pronounced for cholesterol in low-density lipoproteins (LDL) rather than high-density lipoproteins (HDL). The concentrations of serum triacylglycerol were decreased in hypothyroidism. These effects on serum lipids were also seen when the normal rats were pair-fed with the PTU-treated group. 2. Feeding a diet rich in saturated fat and cholesterol further increased cholesterol concentrations in LDL and also elevated that in very-low-density lipoprotein (VLDL) of hypothyroid rats. In euthyroid rats such a diet resulted in a relatively small increase in VLDL cholesterol, whereas LDL cholesterol was decreased. 3. Steady-state concentrations of mRNA for the hepatic LDL receptor were significantly decreased in the livers of hypothyroid rats, but were not significantly changed by high-fat feeding in euthyroid or hypothyroid rats. 4. The expression of the LDL receptor in hepatocytes cultured from hypothyroid rats was decreased relative to the euthyroid controls. 5. Whereas the esterification of cholesterol with oleate in hepatocytes cultured from hypothyroid rats was decreased, the activity of acyl-CoA:cholesterol acyltransferase (ACAT) in the livers of these animals was not changed. 6. High-fat feeding increased the hepatic ACAT activity in normal and hypothyroid rats. 7. Incubation of rat hepatocytes with 10 nM-tri-iodothyronine for 4 h increased the relative concentration of the mRNA for the LDL receptor by 25%. 8. It is therefore concluded that thyroid hormones stimulate the synthesis and expression of the hepatic LDL receptor. Elevated cholesterol concentrations in LDL in hypothyroidism probably result from a primary defect in the expression of the hepatic receptor, rather than indirectly via changes in ACAT activity.

Animals↗
PubMed1990

Cloning of a gene that encodes a new member of the human cytotoxic cell protease family.

A family of unusual serine proteases that are believed to be involved in the effector mechanism of cell-mediated cytotoxicity have previously been described in the mouse. However, in the human only one gene encoding a member has been isolated. By use of a mixture of murine cDNAs as probes, a second human gene has now been isolated. The primary structures of the gene and the predicted protein are very similar to those of the mouse. In addition, in keeping with the postulated involvement in cytolysis, transcripts were detected only in cytotoxic cells. The organization of the coding and noncoding regions of the gene, the clustering of family members, and the chromosomal location, close to the alpha chain of the T cell antigen receptor, are all conserved between human and mouse.

Amino Acid Sequence↗
PubMed1990

Chromosome localization of two human serine protease genes to region 14q11.2----q12 by in situ hybridization.

Two human serine protease genes have been cloned. One corresponds to CTLA1, the human equivalent of the mouse cytotoxic cell protease gene Ctla-1, and the other is novel. Both genes were localized to 14q11.2----q12 by in situ hybridization. This result confirms the assignment of human CTLA1 to 14q11.2----q12 and provides new mapping data for another human serine protease gene located in the same chromosome region.

Chromosome Mapping↗
PubMed1987

In vivo and in vitro models of demyelinating disease, XXIII: Infection by JHM virus of athymic rats.

Wistar Lewis (WL), Long Evans (LE) and other rat strains develop complete resistance to CNS disease when inoculated intracerebrally with 5 x 10(4) PFU/ml of murine hepatitis JHM virus (JHMV) after the 10th day of age (1). Immunosuppression of WL rats following onset of the age-related resistance demonstrated that cyclosporin A (CsA) was partially able to abrogate resistance. Studies on nude (rnu/rnu) rats, their heterozygous (rnu/+) litter mates and genetically related LE rats showed that rnu/+ and LE animals became completely resistant to JHMV before the age of weaning, whereas some rnu/rnu rats, challenged as late as 70 days of age, developed disease symptoms, albeit after a long latent period. These observations indicated that the cellular immune system plays an important role in suppressing the viral disease process in the CNS. When the infection of nude rats was initiated on or after the 15th day of life, the histological lesions were generally small and present in both grey and white matter but were seldom seen in the spinal cord. By contrast in rnu/+, LE and WL rats with late-onset disease symptoms, only the demyelinating-type white matter lesions were present. Mononuclear infiltrates, evident throughout the CNS, of nude rats were sometimes massive near the meningies and within ventricular spaces. JHMV RNA was detectable by dot-blotting analysis in the CNS of both paralysed and asymptomatic rnu/rnu and rnu/+ rats. In-situ hybridization with cDNA probes for JHMV RNA showed that neurons in the hippocampus and cerebellum, as well as cells in the white matter, were frequently infected. The present data indicate that in the rat T cells have an important function in maintaining resistance to the JHMV-related CNS disease. However, even without a functional T cell compartment after 15 days of age nude rats did not develop an acute encephalitis, suggesting that an age-dependent, non-immunological mechanism is also involved in restricting the spread of infection.

Animals↗
PubMed1987

In vivo and in vitro models of demyelinating disease. XVII. The infectious process in athymic rats inoculated with JHM virus.

Wistar Lewis (WL), Long Evans (LE) and other rat strains develop complete resistance to CNS disease when inoculated intracerebrally with murine hepatitis JHM virus (JHMV) after the 10th day of age. Two types of studies were conducted to ascertain the involvement of the cellular immune system in development of resistance. Immunosuppression of WL rats with cyclosporin A (CsA) following onset of the age-related resistance demonstrated that this drug was partially able to abrogate resistance. In the other studies nude (rnu/rnu) rats, their heterozygous (rnu/+) litter mates and genetically related LE rats of various ages were challenged with JHMV. The rnu/+ and LE animals became completely resistant before the age of weaning, whereas some rnu/rnu rats, challenged as late as 70 days of age, showed disease symptoms--albeit after a long latent period. These observations indicated that the cellular immune system plays an important role in suppressing the disease process in the CNS. When the infection of nude rats was initiated on or after the 15th day of life, the histological lesions were generally small and present in both grey and white matter but were seldom seen in the spinal cord. Mononuclear infiltrates were evident throughout the CNS. In some nude rats there was massive mononuclear cell infiltration towards the meningies and into ventricular spaces. By contrast in mu/+, LE and WL rats with late-onset disease symptoms, demyelinating-type lesions were confined to the white matter and only minor infiltration of mononuclear cells was evident. JHMV RNA was detectable by dot-blotting analysis in the CNS of both paralysed and asymptomatic rnu/rnu and rnu/+ rats, but less RNA was usually detected in heterozygous animals. In-situ hybridization with cDNA probes for JHMV RNA showed that neurons in the hippocampus and cerebellum, as well as cells in the white matter, were frequently infected. The present data indicate that in the rat T cells have an important function in maintaining resistance to the JHMV related disease process. However, even without a functional T cell compartment nude rats challenged after 15 days of age did not develop an acute encephalitis, suggesting that an age-dependent, non-immunological mechanism is also involved in restricting the spread of infection. It is possible that resistance in euthymic rats sets in because: (1) at the time of weaning the CNS matures, so that the number of targets available for infection is reduced, (2) T cells prevent the late-onset disease by clearing persistent, low grade infections from the CNS.

Animals↗
PubMed1986

Regulation of viral persistence in human glioblastoma and rhabdomyosarcoma cells infected with coronavirus OC43.

Cultures of human rhabdomyosarcoma (RD) and human glioblastoma (U87-MG) were compared for their ability to sustain a persistent infection with coronavirus OC43. Within 28 days, infectious virus and hemagglutinin were being produced at high levels in both types of cells. Temperature sensitive plaque variants were recovered at 31 degrees C. In both cell types, the virus caused increased antigen synthesis and cell death, if the temperature was lowered to 31 degrees C. Infectious virus was lost if cells were treated with antiserum to whole virus or if the temperature was raised to 39.5 degrees C. Probing the cured cells with OC43-specific 32P-cDNA showed that cured cells contained no detectable viral RNA. The relative ease of establishment and cure of these persistent infectious makes them attractive as models to study coronavirus regulatory processes.

Coronaviridae↗
PubMed1985

In vivo and in vitro models of demyelinating disease: JHM virus in the rat central nervous system localized by in situ cDNA hybridization and immunofluorescent microscopy.

In situ probing of central nervous system (CNS) tissues has made it possible to associate the presence of JHM virus (JHMV) RNA with individual cells in the rat CNS. The presence of viral RNA was not always associated with antigen expression. The in situ hybridization revealed that cerebellar Purkinje cells and hippocampal neurons were highly susceptible to JHMV infection during either acute or paralytic disease. In the paralytic disease, Purkinje cell neurons frequently contained viral RNA. This observation suggests that these neurons, and perhaps others, may be repositories for JHMV in rats that undergo prolonged infections.

Animals↗
PubMed1984

In vivo and in vitro models of demyelinating disease. IX. Progression of JHM virus infection in the central nervous system of the rat during overt and asymptomatic phases.

JHM virus, when inoculated into neonatal rats, can cause either a rapidly fatal acute encephalomyelitis or, after longer incubation periods, a paralytic disease. The cerebrospinal fluid (CSF) and serum anti-JHM virus IgG concentrations present in rats prior to onset of clinical symptoms or during the acute and paralytic phases of disease were compared. High CSF/serum ratios, indicative of local antibody production in the CNS, were noted only where disease was demonstrable suggesting that local antibody production accompanied the infection but did not prevent the neurological disease. Among animals in which neurologic symptoms had not become manifest, only those with elevated CSF/serum ratios were found to have histological CNS lesions. Immunofluorescent microscopy indicated that viral antigens were present in both glia and neurons. Antigen-positive cells were frequently present in histologically normal CNS tissue, while regions of necrosis were antigen negative. Testing for the presence of viral RNA with JHM cDNA probes revealed that the virus was rapidly disseminated throughout the CNS, presumably establishing centers of infection prior to the development of recognizable tissue damage. Viral RNA was also detected in the CNS following recovery from paralysis and as late as 5 months postinfection, where no disease occurred. These findings indicate that, although infection by JHM virus can spread rapidly throughout the CNS, formation of lesions during chronic disease is a slower process. The current data and previous observations suggest that JHM virus can remain in a latent state for periods of at least several months in rats without apparent neurologic disease despite the absence of any known provirus phase in the replicative strategy of coronaviruses.

Animals↗
PubMed1982

In vivo and in vitro models of demyelinating disease: endogenous factors influencing demyelinating disease caused by mouse hepatitis virus in rats and mice.

Intracerebral inoculation of JHM virus (JHMV), the neuropathic strain of mouse hepatitis virus, into Wistar Furth, Wistar Lewis, and Fischer 344 rats at various ages indicated that Wistar Furth rats are more susceptible to the virus than are the other strains. Fischer 344 and Wistar Lewis rats were more resistant to inoculation at 2 and 5 days of age and completely resistant by 10 days of age. In contrast, Wistar Furth rats which were very susceptible at both 2 and 5 days of age remained susceptible until 21 days of age. Intracerebral challenge of an F1 cross between Wistar Furth and Wistar Lewis rats at 10 days of age indicated that resistance to JHMV infection is dominant. Cyclophosphamide treatment 28 days after intracerebral inoculation exacerbated an inapparent infection, leading to paralysis in eight of nine and death in six of nine Wistar Furth test rats. In such immunosuppressed animals, grey- and white-matter lesions were noted throughout the central nervous system, in contrast to the purely demyelinating lesions noted previously. Since rats, unlike mice, were not susceptible to disease after intracerebral injection with the serorelated viscerotropic strain MHV-3, we wished to extend our understanding of the neurological disease process elicited by the two viruses in rodents. For this reason, various mouse strains, including some with recognized immunodeficiencies, were challenged by different routes of inoculation. Intraperitoneal infection of nude and beige mice with JHMV indicated that lack of natural killer cell functions does not markedly enhance the susceptibility to virus, whereas T-cell activity appears to be essential for resisting infection. JHMV and MHV-3 replication in peritoneal macrophages from highly resistant A/J mice was reduced in comparison with that noted in macrophages from susceptible C57BL6/J mice. An initial intraperitoneal inoculation of JHMV was able to protect C57BL6/J mice against fatal intracerebral challenge within 3 days, whereas A/J mice remained susceptible beyond day 3. The protective effect did not appear to result from increased levels of circulating interferon, preceded elevation in serum JHMV-neutralizing antibody titers, and persisted for at least several weeks after intraperitoneal inoculation. Based on the combined studies described here and on previous work by us and others, it appears that the factors influencing the outcome of coronavirus disease in rodents are age at inoculation, route of challenge, genetic constitution of the virus and host, and competence of the immune system, particularly cellular immunity involving T-cells.

Aging↗
PubMed1982

High-sensitivity optical lymph flow-meter.

An optical flow-meter is described which allows precise and continuous registration of the flow of lymph from cannulated human lymph vessels. The cannula from the lymph vessel is connected to the measurement tubing of the instrument where the flow is measured by automatically monitoring the movement of an air bubble introduced into the flow at the beginning of the measurement. The limit of sensitivity of the instrument is about 0.1 microliter, allowing reliable registration of stroke volumes of about 1 microliter which typically occur in human leg lymphatics. The size and capacity of the instrument were chosen to be suitable for clinical use. A technical description of the instrument is given. Application of the instrument is illustrated with recording of lymph flow and lateral intralymphatic pressure in a prenodal lymph vessel of the human leg.

Lymph↗
PubMed1980

In vivo and in vitro models of demyelinating diseases. III. JHM virus infection of rats.

Suckling rats of three inbred and three outbred strains were inoculated intraperitoneally (P) or intracerebrally (IC) with the JHM strain of mouse hepatitis virus (JHMV) and were monitored for evidence of neurologic diseases. Consequences of varying age at inoculation, route of injection, and virus dose were ascertained. No disease was evident after IP injection but IC inoculation with at least 10(4) plaque-forming units at 2 days of age resulted in either a rapidly fatal encephalitis or a chronic, progressive, fatal neurologic disease in most rats, regardless of strain. Inoculation at 5 or 10 days of age predominantly caused the chronic neurologic disease, characterized by demyelinating lesions in the brain, spinal cord, or optic nerve, which sometimes were evident as late as several months postinoculation. Demyelination in the optic nerve proved to be concurrent with demyelinating lesions elsewhere in the CNS. Occasionally, clinical remissions were observed in rats in which posterior paralysis developed, suggesting that remyelination in the rat can occur. Demonstration of virus replication, by infectivity, in rats exhibiting neurologic disease and in rats without clinical symptoms was substantiated by electron microscopic observations of virus development and assembly in oligodendroglia of the optic nerve and spinal cord. In view of the protracted course of the disease in some rats, presence of demyelinating lesions confirmed by light and electron microscopy, and remissions of clinical symptoms, the JHMV-infected rat seems to be an appropriate animal model to study virus-mediated progressive demyelinating disease.

Animals↗