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Biomedical subjects

G Nilsson

Publications and source records attributed to G Nilsson.

At least 19 recordsLinked to original sources
PubMed1992

Recombinant human stem cell factor stimulates differentiation of mast cells from dispersed human fetal liver cells.

We have previously shown the development in vitro of tryptase+ human mast cells from fetal liver cells cocultured with murine 3T3 fibroblasts. In this study, recombinant human stem cell factor (rhuSCF), the ligand for the c-kit proto-oncogene product called Kit, stimulated the growth and differentiation primarily of mast cells from dispersed fetal liver cells, whereas recombinant human interleukin-3 (rhuIL-3) stimulated the differentiation of basophils along with other cell types. Cultures of fetal liver cells were initiated and maintained in the presence of rhuSCF or rhuIL-3 for up to 6 weeks. Metachromatic cells in cytospins were identified as mast cells primarily on the basis of tryptase expression, and as MCT or MCTC by immunohistochemistry using monoclonal antibodies against tryptase and chymase, whereas basophils were metachromatic, polymorphonuclear, and lacked these proteases. Levels of tryptase and histamine were measured by radioimmunoassay, tryptase and chymase activities by peptide hydrolysis, and cell surface Kit by flow cytometry with the monoclonal antibody YB5.B8. The predominant presence of mast cells occurred only in the cultures supplemented with rhuSCF. The percentage and total number of mast cells increased over time with increasing concentrations of rhuSCF and reached a plateau at 55 ng/mL. At this concentration of rhuSCF, mast cells first appeared by day 7; by day 42, 106% of the starting number of cells were present and 85% of these were tryptase+, 31% being weakly chymase+. These mast cells appeared immature by ultrastructural criteria; most cells were mononuclear, but some had nuclei with deeply divided lobes. DNA synthesis in tryptase+ mast cells at days 21 and 28 of culture with rhuSCF was demonstrated by incorporation of bromodeoxyuridine. Calculated levels of histamine (1.2 pg/mast cell) and tryptase (0.9 pg/mast cell) were similar to those determined previously in coculture experiments with murine 3T3 fibroblasts. Chymase activity was undetectable in most cell extracts. On day 0, 4% to 20% of fetal liver cells expressed cell surface Kit. In the presence of rhuSCF, the percentages and total numbers of Kit+ cells and the apparent concentration of Kit per cell increased along with the number of tryptase+ cells. In the presence of rhuIL-3, toluidine blue+, tryptase- cells first and maximally appeared at day 14 (11% +/- 2.5%). The percentage of these toluidine blue+ cells then declined to about 6% by days 21 and 35, while the total number of positive cells declined over 10-fold. Kit+ cells in the presence of rhuIL-3 declined from 9% on day 3 to 2% on day 35.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗
PubMed1992

Postpausal ventricular fibrillation analyzed by Holter-ECG: a case report.

A 70-year-old male patient with a myocardial infarction, 3 months previously, happened to be wearing a Holter monitor at cardiac arrest during micturition. The patient had ventricular fibrillation (VF) and was successfully resuscitated by means of defibrillation. Analysis of the Holter tape revealed atrial fibrillation and secondary ventricular premature beats (VPB), i.e., VPBs dependent upon a relatively long interval between the two preceding heartbeats. The VF was preceded by an especially long R-R interval (1.45 sec) following a run of especially short R-R intervals implying the sharpest deceleration of the ventricular rate during 1 hour Holter recording preceding the cardiac arrest. A peculiar large alteration of the T wave configuration was also found to precede the VF.

Aged↗
PubMed1992

Effects of omeprazole and ranitidine on plasma gastrin concentration and stomach gastrin content in rats.

Prolonged fasting and longer time between dosing and sampling reduced the plasma gastrin concentrations after omeprazole (80 mumol/kg x 2 for 14 days) treatment in male rats whereas the amounts of tissue gastrin were essentially unchanged during these initial experiments. After 28 days omeprazole (80 mumol/kg x 2) or ranitidine (375 mumol/kg x 4) that produced corresponding inhibition of acid secretion, increased the tissue gastrin content by 114 and 59%. A low dose of omeprazole (20 mumol/kg x 2) also raised the gastric gastrin content (41%), whereas no change was noted on treatment with a low dose of ranitidine (125 mumol x 4). Following recovery for 28 days no significant increases in gastrin were observed. 1, 3, 7, 14 or 28 days of treatment with omeprazole (80 mumol/kg x 2) gradually increased the gastric gastrin content being significantly raised already after 3 days. We conclude that a) measuring the tissue gastrin content may be the preferable method when changes in gastrin following long-term treatment with acid inhibiting drugs are to be determined, b) the amount of gastrin in the stomach increases rapidly following treatment with omeprazole and is approximately doubled following 28 days of treatment and c) after treatment for 28 days omeprazole was found to cause greater elevations in the tissue gastrin content than ranitidine despite similar degrees of basal acid inhibition.

Analysis of Variance↗
PubMed1992

Characterization of human mast cells developed in vitro from fetal liver cells cocultured with murine 3T3 fibroblasts.

Cocultures of dispersed human fetal liver cells with murine Swiss 3T3 fibroblasts resulted in the development of human mast cells after 1 to 4 weeks of culture. Mast cells were detected by immunohistochemistry using a murine monoclonal anti-tryptase antibody, before metachromasia appeared with toluidine blue. When subjected to double immunohistochemistry using murine monoclonal anti-chymase and anti-tryptase antibodies, 94% +/- 10% (SD) of the mast cells seen at day 30 of culture were of the MCT type. These results contrast with those obtained with human mast cells derived from cord blood mononuclear cells cocultured with murine 3T3 fibroblasts which are comprised of substantially greater numbers of MCTC cells, averaging 48% +/- 31% (SD) at day 30 of culture. Mast cells developed in vitro from fetal liver cells or cord blood mononuclear cells contained similar amounts (+/- SD) of histamine (0.9 +/- 0.5 pg/cell and 1.1 +/- 1 pg/cell, respectively) and tryptase (1.7 +/- 0.4 pg/cell and 1.9 +/- 1.2 pg/cell, respectively) on day 30 of culture. Fetal-liver-derived mast cells from a 30-day-old culture were identified by immunoelectron microscopy using gold-labelled antitryptase antibody. Typically, these mast cells appeared immature as they had large nuclear to cytoplasmic ratio and a small number of ill-formed cytoplasmic granules. For both fetal-liver- and cord-blood-derived mast cells, there was no evidence of conversion of the MCT type into the MCTC type provided by this study. These results suggest that commitment to develop as an MCT or MCTC type of mast cell may have occurred in mast cell precursors present in fetal liver and cord blood mononuclear cells, prior to granulation.

Animals↗
PubMed1992

Studies of a proposed mechanism regulating parietal cell emptying.

We have proposed and provided experimental evidence for the existence of a mechanism controlling the output of hydrochloric acid from the parietal cells. On stimulation of the cells, histamine not only activates the H+/K-pump but also prevents acid from leaving the cell. The delay may be caused by cAMP activation. When the appropriate conditions have been obtained, the acid leaves the cell and enters the gastric lumen. A delay in onset of acid secretion is convenient from several points of view. For example, salivary amylase, which is responsible for approximately 50% of the carbohydrate digestion, will have time to exert its digesting effect in the stomach before the pH decreases and the enzyme becomes inactivated. Also, bicarbonate secretion will be started before high concentrations of acid have been obtained in the stomach and thereby contributes to protection of gastric mucosa.

Aminopyrine↗
PubMed1991

Distribution patterns of ventricular premature complexes in long-term electrocardiographic recordings and their usefulness in disclosing modulated parasystole.

Long-term electrocardiographic recordings from 25 patients with abundant ventricular premature complexes (VPCs) were screened with a computer program for sequences of interectopic intervals with the number of sinus beats consistent with manifest or concealed bigeminy/trigeminy. On average, 19.0% of VPCs in this patient series were followed by an uninterrupted sequence of greater than or equal to 10 interectopic intervals with concealed bigeminy. The corresponding figure for concealed trigeminy was 2.2%, for manifest bigeminy 9.6%, and for manifest trigeminy 0.8%. The longest sequence with concealed bigeminy comprised 149 interectopic intervals. The corresponding figure for concealed trigeminy was 135 interectopic intervals. The sequences of concealed bigeminy occurred at significantly lower heart rates than those of concealed trigeminy. These findings can be explained by the entrainment phenomena described in experimental models of modulation of a ventricular parasystolic focus across a zone of impaired conduction.

Adult↗
PubMed1991

M-component with reactivity against actin associated with thrombotic thrombocytopenic purpura.

A patient with a monoclonal B-cell disorder producing an M-component with antiactin activity is described. After more than 3 years of observations, the final diagnosis is not completely established, but a malignant lymphoproliferative process is evidently under evolution. On three occasions, she has presented with symptoms compatible with a thrombotic thrombocytopenic purpura-like syndrome, concomitant with an increase in paraprotein. A relationship between this autoantibody and the patient's symptoms is proposed. Steroids have so far had a beneficial effect on the symptoms.

Actins↗
PubMed1991

Effects on immune responses in rats after neuromanipulation with capsaicin.

The effect of capsaicin treatment on the immune response, assessed as antibody formation in vivo and in vitro, was studied in ovalbumin (OA)-immunized rates. Rats were treated with capsaicin at 1-2 days of life or at adult age, before or after immunization. The levels of IgA, IgE and IgG antibodies as well as immunoglobulins were measured in serum and supernatants from cultured lymph node cells, spleen cells and peripheral blood lymphocytes. Capsaicin treatment affected the antibody levels depending on the timing of capsaicin treatment in relation to immunization. Different effects of capsaicin treatment were also observed on the different immunoglobulin isotypes. One of the most striking effects by capsaicin treatment was the reduction of IgA and IgG synthesis in cultured lymphoid cells from aerosol immunized animals treated with capsaicin after immunization. In contrast, in vivo the level of total serum IgA was increased in similarly treated animals. In this study we show that capsaicin treatment, which is known to decrease the levels of neuropeptides of sensory origin, has a time-dependent effect on both antibody levels in vivo as well as the formation of immunoglobulin in vitro. Although the mechanisms responsible for this are not obvious, we conclude a link between depletion of neuropeptides in sensory nerves and the antibody synthesis.

Animals↗
PubMed1991

Enhancement of IgE synthesis in the human myeloma cell line U-266 with an IgE binding factor from a human T-cell line.

An IgE-binding factor(s) (IgE-BF(s] was partially purified from the supernatant of human HTLV-II carrying T-cell line MO. This IgE-BF(s) was shown to increase the IgE synthesis in the human myeloma cell line U-266, but did not affect its viability or growth. The effect of the IgE-BF(s) was dose-dependent and selective for IgE protein synthesis as beta 2-microglobulin synthesis in the U-266 and the immunoglobulin production in the U-1958 IgG-secreting human myeloma cell line were unaffected. The IgE-BF(s) increased the production of the epsilon heavy chain but not the lambda light chain production. The IgE-BF(s) was distinct from IL-1 beta, IL-3, IL-4, IL-5, IL-6, TNF-alpha, IFN-alpha, -beta, -gamma, M-CSF, and fragments of CD23.

Cytokines↗
PubMed1991

Local immune response and bronchial reactivity in rats after capsaicin treatment.

The interaction between the nervous system, immune system and bronchial reactivity was studied in rats by using the neurotoxin capsaicin. Rats were treated with capsaicin at 1-2 days of age or at adult age, before or after sensitization by subcutaneous injections with ovalbumin (OA). The levels of the neuropeptides neurokinin A and calcitonin gene-related peptide were decreased in the lung after capsaicin treatment, as determined with radioimmunoassay, whereas the levels of neuropeptide Y were unaffected. The levels of IgA, IgE and IgG in bronchial lavage were also affected by capsaicin treatment; however, the results were heterogeneous. Capsaicin treatment after sensitization reduced the bronchial reactivity to challenge with OA aerosol and serotonin iv. The results demonstrated that reduction of neuropeptide levels with capsaicin affected both bronchial reactivity and the levels of antibodies in bronchial lavage fluid. However, no correlation between these two parameters was seen, demonstrating the complexity of the system.

Animals↗
PubMed1991

Sensory neuropeptide involvement in animal models of airway irritation and of allergen-evoked asthma.

C-fiber afferents in the airways are in close contact with mast cells and are activated both upon allergic reactions and by inhalation of irritants such as capsaicin and cigarette smoke. This evokes both protective reflexes such as cough as well as local release of tachykinins and calcitonin gene-related peptide (CGRP) with subsequent actions on blood vessels (vasodilatation and plasma protein extravasation) and bronchial smooth muscle (bronchoconstriction). After capsaicin pretreatment when peptides have been depleted from the sensory nerves, there is a marked reduction of the vasodilatatory response upon allergen challenge and the protein extravasation evoked by cigarette smoke. Conversely, chronic cigarette smoke exposure is accompanied by increased coughing to capsaicin challenge. Furthermore, aerosol immunization and chronic smoke exposure are both associated with elevated tissue levels of CGRP, suggesting upregulation of C-fiber function and peptide synthesis, which may contribute to airway hyperreactivity.

Aerosols↗
PubMed1990

Time course of inhibition of gastric acid secretion by omeprazole and ranitidine in gastric fistula rats.

Basal, pentagastrin- and histamine-stimulated acid secretion were measured in gastric fistula rats treated with the H+/K(+)-ATPase inhibitor, omeprazole, and the H2-receptor antagonist, ranitidine. All doses of omeprazole (20, 30, 40, 80, 400 mumol/kg) and ranitidine (125, 187.5, 250, 375 mumol/kg) essentially abolished the basal acid output for various periods of time. Omeprazole, 80 mumol/kg, administered twice daily, reduced the 24-h basal acid secretion more effectively than did 400 mumol/kg given once daily. Four daily administrations of ranitidine reduced the 24-h basal acid output to a similar extent as omeprazole administered twice. Omeprazole (20, 80 mumol/kg) was more effective than ranitidine (125, 375 mumol/kg) in inhibiting acid secretion evoked by maximal doses of pentagastrin (650 nmol/kg per h) and histamine dihydrochloride (136 mumol/kg), whereas this difference was less pronounced for the inhibition of acid responses induced by a threshold dose (1.1 mumol/kg) of histamine. The inhibition evoked by omeprazole (80 mumol/kg x 2) and ranitidine (375 mumol/kg x 4) of basal and histamine (1.1 and 136 mumol/kg)-induced acid secretion was similar after 1 and 4 weeks of treatment. After the end of drug administration, the acid secretion induced by threshold doses of histamine was significantly elevated in the omeprazole-treated rats, whereas no significant hypersecretion of acid was seen during the recovery period in rats treated with ranitidine. Plasma gastrin concentrations were significantly elevated after 4 weeks of treatment with omeprazole but returned to pretreatment levels after 4 weeks of recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Peptidergic innervation of rat lymphoid tissue and lung: relation to mast cells and sensitivity to capsaicin and immunization.

The peptidergic innervation of lymphoid tissue and the lung in relation to mast cells was studied in rat. The sensitivity of neuropeptide-containing nerves to capsaicin treatment and immunization was also examined. Measurements of the content of neurokinin A and calcitonin gene-related peptide revealed that the lung contained the highest content of both neuropeptides; lymph nodes had intermediate levels, whereas the spleen had the lowest content. Immunohistochemistry showed that the calcitonin gene-related peptide- and neurokinin A-immunoreactive nerves in lymph nodes were mainly found around blood vessels, whereas in the lung the nerves were present within the lining respiratory epithelium, bronchial smooth muscle, around blood vessels and close to lymphoid aggregates. Combined immunohistochemistry for serotonin (5-hydroxytryptamine), as a marker for mast cells, and tachykinins or calcitonin gene-related peptide revealed that a close association was often present between the nerves and 5-hydroxytryptamine-positive cells in the bronchi of the lung, while 5-hydroxytryptamine-positive cells were not observed in lymph nodes. The neurokinin A and calcitonin gene-related peptide content in lymph nodes, spleen and lung, but not the content of neuropeptide Y, was markedly decreased by capsaicin treatment, suggesting a sensory origin for the two former peptides. Aerosol immunization increased the levels of calcitonin gene-related peptide in the lung, whereas the content in mediastinal lymph nodes was not affected. These data demonstrate a peptidergic innervation mainly of blood vessels in lymphoid tissue and a close relation between sensory nerves and mast cells as well as lymphoid aggregates in the bronchi of the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Accumulation of CD8+ cells after immunization with soluble antigen.

Rats were immunized with ovalbumin, either subcutaneously or by aerosol inhalation. The lymphocyte distribution in lymph nodes, peripheral blood, and spleen was investigated by flow cytometry after labelling with T pan (OX19 and W3/13), T helper lymphocytes (W3/25), T cytotoxic/suppressor lymphocytes (OX8), kappa light chain (MAR 18-5), or MHC class II (OX6) monoclonal antibodies. The influence of the neurotoxic agent capsaicin on the lymphocyte distribution was also analysed. Subcutaneous immunization resulted in an increased number of OX8+ cells in mesenteric lymph nodes, spleen, and peripheral blood but not in the draining lymph nodes, axillary, brachial, and mediastinal lymph nodes. The number of positive cells for the other cell markers used were not affected by immunization. The neuromodulatory effect of capsaicin had no effect on the lymphocyte distribution. The results showed that the type of immunization used, low amounts of antigen without adjuvant given during a prolonged period, selectively induced OX8+ cells. The patterns were unaffected by neuromodulation using capsaicin.

Animals↗