PubMed Health⌕ Search

Biomedical subjects

J Janus

Publications and source records attributed to J Janus.

At least 19 recordsLinked to original sources
PubMed1998

Medullomyoblastoma: a histological, immunohistochemical, ultrastructural and molecular genetic study.

Medullomyoblastoma is a rare variant of medulloblastoma containing myoblastic elements. A 9-year-old boy developed a cerebellar syndrome and signs of increased intracranial pressure, the cause of which was a tumor of the cerebellar vermis measuring 7 x 4.5 x 4.5 cm. Morphologically the tumor largely consisted of a medulloblastoma component but displayed glial, myoblastic and ganglionic differentiation on light microscopic, immunohistochemical and ultrastructural examination. The non-enhancing rim of the tumor on magnetic resonance imaging showed extensive ganglionic differentiation. The tumor did not express bcl-2, c-myc, or c-erb-B2 oncoproteins and was negative for the p53 gene product. On molecular genetic studies, the tumor did not show allelic loss on chromosome loci, frequently altered in medulloblastomas, such as 17p, 1q and 9q.

Cerebellar Neoplasms↗
PubMed1997

Cytokine production by dengue virus antigen-responsive human T lymphocytes in vitro examined using a double immunocytochemical technique.

A number of studies suggest that cytokines may contribute to the pathogenesis of viral infections, including dengue. In this study, we developed a double immunocytochemical method and characterized cytokine-producing cells in the peripheral blood mononuclear cells (PBMC) of dengue virus-immune donors after in vitro stimulation with specific dengue antigens. We found that double immunostaining using immunoalkaline phosphatase (Vector blue) for cytokines [interferon-gamma (IFN-gamma), interleukin (IL) -2, -4, -1alpha, -1beta, and -6, tumor necrosis factor beta (TNF-beta), and TNF-alpha] and immunoperoxidase [diaminobenzidine (DAB)] for cell surface markers (CD3, CD4, CD8, CD20, and CD68) provided the best distinction of double-positive cells from single-positive or -negative cells. The number of IFN-gamma, IL-2, IL-4, and TNF-beta-positive cells increased 2 or 3 days after stimulation with specific dengue antigens. No or very few cytokine-producing cells were detected in the PBMC of non-immune donors stimulated with dengue antigens and the PBMC of immune donors stimulated with a control antigen. The analysis of cell surface markers showed that mainly CD4+ and CD8+ T cells produced these cytokines. The results obtained by immunocytochemistry were consistent with cytokine levels detected in the culture medium assayed by enzyme-linked immunosorbent assay. In conclusion, this double immunocytochemistry technique is suitable for the detection and characterization of cytokine-producing cells in PBMC. Furthermore, the results support the hypothesis that antigen-stimulated CD4+ and CD8+ T cells produce cytokines that may play a role in the pathogenesis of dengue virus infection.

Animals↗
PubMed1997

Effects of methylphenidate on oxytocin and vasopressin levels in pinealectomized rats during light-dark cycle.

Although previous reports have shown that methylphenidate (MPH), in addition to its known behavioral effect, can influence the hypothalamo-pituitary-adrenal axis by increasing the plasma ACTH, the pineal gland seems to be involved in neuroendocrinological processes too, e.g., in hypothalamic synthesis and release of oxytocin (OXY) and vasopressin (AVP). Therefore, a study was performed to measure the OXY and AVP content of the hypothalamus, neurohypophysis, and plasma after application of MPH in the morning and evening in pinealectomized (PE) as well as sham-operated control (SO) rats. Pinealectomy influenced both the daily pattern (reversed in the neurohypophysis) and the levels of OXY and AVP. Starting from this different situation, application of MPH produced diverse effects. Hypothalamus: PE, increase in both hormones in the morning and evening; SO, decrease in morning OXY level. Neurohypophysis: PE, increase in morning OXY level; SO, decrease in both hormones even though in the morning only. Plasma: PE, decrease in morning OXY concentration; SO, increase in both hormones in the morning and decrease in the evening. The present results indicate that MPH application influences the hypothalamo-neurohypophysial system. Furthermore, the hypothesis has been supported that this influence may be dependent on the circadian activity of the pineal gland as well.

Animals↗
PubMed1997

Rapid diagnosis of dengue viremia by reverse transcriptase-polymerase chain reaction using 3'-noncoding region universal primers.

A reverse transcriptase-polymerase chain reaction (RT-PCR) method was developed as a rapid diagnostic test of dengue viremia. To detect dengue viruses in serum or plasma specimens, a pair of universal primers was designed for use in the RT-PCR. Using these primers, the 3'-noncoding region of dengue virus types 1, 2, 3, and 4 could be amplified, but not those of other flaviviruses, such as West Nile virus, Japanese encephalitis virus, and yellow fever virus, or the alphavirus Sindbis virus. The sensitivity of the RT-PCR assay was similar to that of a quantitative fluorescent focus assay of dengue viruses in cell culture. Combining a silica method for RNA isolation and RT-PCR dengue virus could be detected in a 6-hr assay. In a preliminary study using this method, we detected dengue virus in 38 of 39 plasma specimens from which dengue virus had been isolated by mosquito inoculation. We then applied this method for detecting dengue viremia to 117 plasma samples from 62 children with acute febrile illnesses in a dengue-endemic area. We detected dengue viremia in 19 of 20 samples obtained on the day of presentation, which had been confirmed as acute dengue infection by mosquito inoculation and antibody responses. The overall sensitivity of this method was 91.4% (32 of 35; 95% confidence interval [CI] = 82.2-100%). The results from testing plasma samples from febrile nondengue patients showed a specificity of 95.4% (42 of 44; 95% CI = 89.3-100%).

Acute Disease↗
PubMed1996

The CTFA Evaluation of Alternatives Program: an evaluation of in vitro alternatives to the Draize primary eye irritation test. (Phase III) surfactant-based formulations.

The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data.

Animal Testing Alternatives↗
PubMed1996

Ki-67 and biological behaviour in meningeal haemangiopericytomas.

The biological behaviour of meningeal haemangiopericytomas was retrospectively studied using immunohistochemical staining with MIB1, a monoclonal antibody against the Ki-67 antigen, a nuclear protein related to cell proliferation. Paraffin-embedded material from 62 tumours from 40 patients were investigated. The proliferating compartment of the tumours was estimated by evaluating the MIB1 staining index, i.e. the percentage of MIB1 positive nuclei in at least 1000 counted tumour cells in representative areas. The staining index ranged from 1.24% to 39.01%. Statistical analysis revealed no significant correlation between the staining index and recurrence-free survival (chi 2 = 0.3922, P = 0.5311). Long-term observation (> 100 months), however, revealed a tendency to longer survival in the group with a staining index less than 5%. According to our results, the MIB1 staining index does not contribute to the accuracy of predicting the clinical outcome of meningeal haemangiopericytomas.

Adolescent↗
PubMed1996

[Tumorous neurosarcoidosis--a rare manifestation of Boeck disease--3 cases and review of the literature].

Neurosarcoidosis mimicking CNS tumours represents a rare manifestation of Schaumann's disease. The central or peripheral nervous system is clinically involved in 5% of sarcoidosis, basal parts of the brain being mainly affected by the inflammation. This location of the process causes basal meningitis with cranial nerve paresis as well as parenchymal granulomatosis around the third ventricle and hypophysis. Solid, space-occupying lesions rarely occur, evoking problems in the differentiation from cerebral tumours. We report three cases of neurosarcoidosis presenting as intracranial tumours, where a space-occupying lesion was the first of only manifestation of sarcoidosis. The lesions in our cases were found in parietal and parieto-occipital cortex and in the fourth ventricle and vermis cerebelli, respectively. These locations are unusual, since most of the reported cases were affecting the temporal lobe. We review the literature and discuss the role of neurosarcoidosis in the differential diagnosis of intracranial tumours.

Brain↗
PubMed1995

Modulation of the functions of dengue virus-specific human CD8+ cytotoxic T cell clone by IL-2, IL-7 and IFN gamma.

Lymphokines play an important role in immune responses to viruses by modulating functions of T lymphocytes. In the present study, we examined the effects of interleukin-2 (IL-2), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-7 (IL-7), and interferon gamma (IFN gamma) on proliferation, cytotoxic activity and lymphokine production of a dengue virus-specific CD8+ human cytotoxic T lymphocyte (CTL) clone. IL-2 and IL-7 induced proliferation of the CD8+ CTL clone in the presence or absence of specific antigen, while IFN gamma suppressed proliferation of the clone. IL-7 and IFN gamma augmented dengue virus-specific cytotoxic activity without inducing non-specific cytotoxic activity, and IL-2 induced non-specific cytotoxic activity. IL-2 induced IFN gamma production by the CD8+ CTL clone. IL-4 and IL-6 did not modulate the functions of the CD8+ CTL clone in these experimental conditions. These results suggest that functions of dengue virus-specific CD8+ CTL are modulated by IL-2, IL-7 and IFN gamma, and that IL-7 is a lymphokine useful to induce growth and to maintain specific cytotoxic activity of CD8+ CTL clones in vitro.

Cytotoxicity, Immunologic↗
PubMed1995

T cell activation in vivo by dengue virus infection.

It is accepted that T cells play a critical role during virus infections; however, T cell responses in vivo in acute stage of virus infection are not understood. We examined T cell activation in vivo in two volunteers who developed dengue fever in response to vaccination with a candidate live dengue vaccine. Serial plasma collected from the volunteers from day 0 (before infection) to day 17 after infection were examined for levels of soluble interleukin-2 receptor (sIL-2R), soluble CD4 (sCD4), soluble CD8 (sCD8), interleukin-2 (IL-2) and interferon gamma (INF gamma). Elevation of the levels of sIL-2R, IFN gamma, sCD4 and IL-2 became obvious during the period of viremia and was followed by a later increase in the level of sCD8. The levels of IFN gamma and sIL-2R declined after the end of the period of viremia. These results indicate that i. T cells are activated in vivo by dengue virus infection ii. activation of CD4+ T cells occurs during the period of viremia iii. activation of CD8+ T cells follows CD4+ T cell activation. These results suggest that activation of T cells in vivo may contribute to controlling acute dengue virus infections.

Adult↗
PubMed1994

Immunopathologic mechanisms of dengue hemorrhagic fever and dengue shock syndrome.

Dengue virus infections are a major cause of morbidity and mortality in tropical and subtropical areas of the world. The immunopathological mechanisms that result in severe complications of dengue virus infection, i.e. dengue hemorrhagic fever (DHF), are important to determine. Primary dengue virus infections induce serotype-specific and serotype-cross-reactive, CD4+ and CD8+ memory cytotoxic T lymphocytes (CTL). In secondary infections with a virus of a different serotype from that which caused primary infections, the presence of cross-reactive non-neutralizing antibodies results in an increased number of infected monocytes by dengue virus--antibody complexes. This in turn results in marked activation of serotype cross-reactive CD4+ and CD8+ memory CTL. We hypothesize that the rapid release of cytokines and chemical mediators caused by T cell activation and by CTL-mediated lysis of dengue virus-infected monocytes triggers the plasma leakage and hemorrhage that occurs in DHF.

Cross Reactions↗
PubMed1994

Primary influenza A virus infection induces cross-reactive antibodies that enhance uptake of virus into Fc receptor-bearing cells.

Sera of young children who had had a primary infection with influenza A virus or were immunized with a live attenuated influenza A virus vaccine were examined for antibody responses that neutralized virus or enhanced uptake of virus into Fc receptor-bearing cells, because antibodies that enhance uptake of influenza virus into Fc receptor-bearing cells have been reported using mouse immune serum and monoclonal antibodies. The neutralizing antibody titers to the homologous infecting virus and to another H1N1 virus isolated several years later were higher after natural infection than after infection with the live attenuated virus. Natural infection and the attenuated vaccine induced antibodies that enhanced uptake of homologous virus and H1N1 virus isolated several years later. These results demonstrate that primary influenza A virus infection results in the induction of infection-enhancing antibodies.

Animals↗
PubMed1994

When the patient asks for the results of her mammogram, how should the radiologist reply?

More and more, the patient expects the radiologist to answer her questions about the results of her mammogram. Yet many radiologists are concerned about the way they should reply. Many radiologists are unsure what the referring physicians would want them to say and what other radiologists would consider appropriate. In this continuing attempt to redefine radiologists' responsibilities and their changing roles, the radiologist and the referring physician too often omit the key factor in every medical equation: what the patient wants.

Breast Neoplasms↗
PubMed1992

Dengue virus infection of human skin fibroblasts in vitro production of IFN-beta, IL-6 and GM-CSF.

Dengue virus is transmitted to humans by the bite of infected mosquitos. In our efforts to understand the pathogenesis of dengue virus infection, we examined whether skin fibroblasts can be infected in vitro with dengue viruses. Fibroblasts could be infected with dengue viruses, yellow fever virus and West Nile virus. Dengue virus antigen-positive cells were detected as early as 4 h and the percentage of dengue virus antigen-positive cells reached maximum levels by 24 h after infection. High titers of infectious dengue virus were also detected in the culture supernatants at 20 h after infection. Dengue virus-infected fibroblasts produced interferon-beta (IFN-beta), and the IFN-beta protected uninfected fibroblasts from dengue virus infection. Dengue virus-infected fibroblasts also produced interleukin 6 (IL-6) and granulocyte macrophage colony stimulation factor (GM-CSF). These results suggest that skin fibroblasts may be one of the cell types which first support dengue virus and other flavivirus infections in vivo after introduction by the bite of infected mosquito, and that production of IFN-beta, IL-6, and GM-CSF by these virus-infected fibroblasts may be important host immune responses to control flavivirus infections.

Cells, Cultured↗
PubMed1991

Activation of T lymphocytes in dengue virus infections. High levels of soluble interleukin 2 receptor, soluble CD4, soluble CD8, interleukin 2, and interferon-gamma in sera of children with dengue.

It has been reported that the severe complication of dengue virus infection, dengue hemorrhagic fever (DHF) is much more commonly observed during secondary dengue virus infections than primary infections. In order to elucidate the role of T lymphocytes in the pathogenesis of DHF, we attempted to determine whether T lymphocytes are activated in vivo during dengue virus infections, by examining the levels of soluble IL-2 receptor (sIL-2R), soluble CD4 (sCD4), soluble CD8 (sCD8), interleukin-2 (IL-2) and interferon-gamma (IFN gamma) in the sera of 59 patients with DHF and 41 patients with dengue fever (DF). The levels of sIL-2R, sCD4, sCD8, IL-2, and IFN gamma were significantly higher in the acute sera of patients with DHF than in the sera of healthy children (P less than 0.001 for all markers). The acute sera of patients with DF contained higher levels of sIL-2R, sCD4, IL-2, and IFN gamma than the sera of healthy children (P less than 0.001 for sIL-2R, IL-2, and IFN gamma; P less than 0.05 for sCD4), but did not have elevated levels of sCD8. The levels of sIL-2R (P less than 0.05), sCD4 (P less than 0.001), and sCD8 (P less than 0.001) were higher in DHF than in DF on days 3-4 after the onset of fever. The levels of IL-2 and IFN gamma in patients with DHF were highest 1 d before defervescence. There were no significant differences in the levels of sIL-2R, sCD4, sCD8, IL-2, and IFN gamma among grades 1, 2, and 3 of DHF. These results indicate (a) T lymphocytes are activated and produce IL-2 and IFN gamma in vivo during DHF and DF, (b) CD4+ T lymphocytes are activated in DHF and DF, and the level of activation is higher in DHF than in DF, and (c) activation of CD8+ T lymphocytes is evident in DHF, but not in DF.

Adolescent↗
PubMed1990

Dengue-2 virus infection of human mononuclear cell lines and establishment of persistent infections.

Twenty three human mononuclear cell lines including ten myelomonocytic cell lines, eight B cell lines and five T cell lines, were examined to determine whether they could be infected with dengue-2 virus. All the cell lines were infected with dengue-2 virus as determined by immunofluorescent staining and by virus titration of culture supernatant fluids. K562, Jiyoye and Jurkat, respectively, showed the highest percentage of infected cells of these myelomonocytic, B and T cell lines. Antibody to dengue-2 virus at subneutralizing concentrations augmented dengue-2 virus infection of myelomonocytic cell lines, but not of B cell lines or of T cell lines. Persistent dengue-2 virus infection was established using a myelomonocytic cell line (K562), a B cell line (Raji), and a T cell line (HSB-2). These cell lines maintained a high percentage (more than 70%) of dengue-2 virus antigen-positive cells for at least 25 weeks. Very low titers of infectious dengue-2 virus were detected in the culture supernatant fluids of the persistently infected cells. Dengue-2 virus antigen-positive Raji cell clones were established from persistently-infected Raji cells using limiting dilutions and all of the cells in these clones were dengue-2 virus antigen-positive. These findings demonstrate that a variety of human mononuclear cell lines can be infected with dengue-2 virus and may be useful as models for the analysis of dengue virus-human cell interactions in dengue virus infections.

Antigens, Viral↗
PubMed1990

The vasopressin and oxytocin content in the neurohypophysis under conditions of increased beta-adrenergic transmission in euhydrated and dehydrated rats.

In rats euhydrated or dehydrated for two or four days the neurohypophysial vasopressin and oxytocin content was estimated. Rats were given intracerebroventricularly (i.c.v.) isoprenaline in a daily dose of 10 micrograms dissolved in 10 microliters of 0.9% sodium chloride. The neurohypophysial vasopressor and oxytocic activity diminished progressively during deprivation of water. A single dose of isoprenaline diminished the neurohypophysial content of vasopressin in euhydrated rats. In animals dehydrated for two or four days the depletion of neurohypophysial vasopressin storage (as brought about by osmoreceptor stimulation) was distinctly less marked under treatment with isoprenaline. The neurohypophysial oxytocin storage was diminished by a single dose of isoprenaline; on the contrary, during dehydration isoprenaline distinctly intensified the oxytocin depletion in the neurohypophysis.

Adrenergic Fibers↗