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Biomedical subjects

J Janssen

Publications and source records attributed to J Janssen.

At least 73 records · Page 4Linked to original sources
PubMed1987

Origin of T-lymphocytes in human mixed hematopoietic colonies.

The presence of T-lymphocytes in mixed hematopoietic colonies (CFU-MIX) has been reported by some investigators. Though depletion before culturing was performed, residual T cells might be responsible for the observed phenomenon. Using nondepleted marrow or bone marrow depleted to about 2%, T-lymphocytes could be detected in mixed colonies. However, reduction of the T-lymphocytes to less than 0.7% by using a modified E-rosette technique or a cocktail of anti-T-cell monoclonal antibodies (WT1, WT32, WT82) in the presence of baby rabbit complement, resulted in mixed colonies free of T-lymphocytes. After addition of 1.75% T-lymphocytes to this T-cell-depleted bone marrow, T-lymphocytes could be detected in most mixed colonies, but not after the addition of the same percentage of irradiated T-lymphocytes. The presence of T cells in mixed colonies was determined by an adapted immunofluorescence technique (WT32 plus GAM-FITC). The results indicate that mononuclear cells with T-lymphocyte antigens are not the offspring of mixed hematopoietic colony-forming progenitors, but of a low number of T-lymphocytes contaminating the bone marrow after insufficient T-cell depletion.

Cytological Techniques↗
PubMed1986

Screening for Ureaplasma urealyticum infections in the neonate and the association with prematurity.

Ureaplasma urealyticum has been implicated in gynaecological, obstetrical and neonatal pathology. Increased levels of C-reactive protein and total IgM concentrations in cord blood have often been used as a screening method for infectious disease in the fetus and the newborn. Analysis of the isolation rate of U. urealyticum in function of the concentrations of these two parameters in cord blood showed that U. urealyticum was significantly (P less than 0.05) more frequently isolated when CRP was above normal in cord blood. No correlation between the IgM level in the newborn and the presence of U. urealyticum could be established. A significant relationship was found (P less than 0.01) between Ureaplasma isolation in the urine of mother and child on the one hand and gestational age on the other hand, which supports the hypothesis that U. urealyticum may play a role in preterm delivery.

C-Reactive Protein↗
PubMed1986

Prevention and treatment of supraventricular tachycardia shortly after coronary artery bypass grafting: a randomized open trial.

Supraventricular arrhythmias continue to complicate the postoperative course of patients following coronary artery bypass grafting. In a randomized, open, controlled trial we assessed the value of two different beta-blocking agents in the prevention and treatment of these arrhythmias. Of 151 consecutive patients undergoing coronary artery surgery, 39 were treated with metoprolol and 41 were treated with sotalol (a beta blocker with class III antiarrhythmic properties). Fifty patients served as a control group and received no prophylactic therapy. Twenty-one patients were eliminated from the study for various reasons, making a final total of 130 in the study group. In the metoprolol group 15.3% of patients developed supraventricular tachycardia SVT after coronary artery surgery, which was significantly less (p less than 0.05) than the incidence observed in the control group. However, in the group of patients receiving sotalol, 2.4% developed SVT (p less than 0.01 compared with the control group). Of 18 patients in the control group who developed SVT after randomization, 10 received sotalol and 4 metoprolol to terminate the arrhythmia. The mean time of termination of SVT after drug administration was 2.4 +/- 1.8 hours for treatment with sotalol and 13.6 +/- 9.8 hours for treatment with metoprolol. We conclude that sotalol significantly reduces the incidence of supraventricular tachycardia in the early period after coronary artery bypass surgery.

Adrenergic beta-Antagonists↗
PubMed1986

Cytomegalovirus immunity and T lymphocytes in bone marrow donors and acute graft-versus-host disease.

T lymphocyte subset numbers in bone marrow grafts were correlated with the cytomegalovirus (CMV) antibody status of the donors and with the occurrence of acute graft-versus-host disease (GVHD) in their recipients. We studied whether or not the (previously reported) association between donor CMV antibodies and GVHD could be explained by CMV-related changes in T cell subsets in the marrow grafts. There were no significant correlations between any of the T cell subsets in the marrow grafts and the occurrence of grades II-IV GVHD. A particular subset of CD8+ T cells carrying the HNK1 marker was significantly increased in the marrow grafts of CMV-seropositive donors. Although recipients of marrow from CMV-seropositive donors received an average of five times more CD8+ HNK1+ T cells than those with CMV-seronegative donors, that situation was not associated significantly with the development of GVHD.

Acute Disease↗
PubMed1986

Monitoring of cyclosporin during continuous intravenous administration.

Intravenous cyclosporin was administered continuously to 18 consecutive marrow transplant recipients. Blood samples taken from the single lumen central venous line through which the cyclosporin was administered showed invariably high concentrations. Toxic levels were still present after discontinuation of cyclosporin administration for 8 h, while the peripheral blood levels were in the therapeutic range throughout the observation time. These observations may explain some of the reported discrepancies between the levels of cyclosporin and the side-effects when using intravenous cyclosporin. Mean cyclosporin levels remained stable throughout the 4 weeks of continuous intravenous cyclosporin administration, despite a gradual decrease of the mean cyclosporin dose. Dose adaptations were made based on clinical side-effects and cyclosporin concentrations in blood samples from peripheral veins.

Adolescent↗
PubMed1986

Depletion of donor lymphocytes by counterflow centrifugation successfully prevents acute graft-versus-host disease in matched allogeneic marrow transplantation.

Bone marrow from 22 histocompatible siblings was depleted of 98% of the lymphocytes using a combination of density flotation centrifugation followed by counterflow elutriation. Even with the marrow suppressive influence of methotrexate (MTX), the viability of the hematopoietic stem cells was not affected, as indicated by the normal repopulation after grafting in the evaluable patients. One patient (UPN 9) showed a primary graft failure, possibly resulting from persisting septicemia and long-term antibiotic therapy. Two patients have persistent host lymphocytes, one of whom was examined during relapse; the other remains in remission. Two patients did not receive immunosuppression after bone marrow transplantation (BMT), and acute graft-v-host disease (GVHD) developed in both. Nine patients received MTX as immunosuppression following BMT. GVHD did not develop in any of them, but fatal infections in the immediate posttransplant period developed in five patients. Eleven patients received cyclosporine (CsA) after transplantation. Beginning in week 5 after BMT, CsA was gradually replaced by MTX. Acute GVHD, substantial chronic GVHD, or fatal infections did not develop in any of these patients. Removal of 98% of the lymphocytes by counterflow centrifugation prevents development of acute GVHD, provided that immunosuppression is administered after BMT. Graft rejection was not observed, but the number of evaluable patients is limited at present.

Adolescent↗
PubMedDate not supplied

Caffeine fatality: a case report.

A case of fatal caffeine toxicity due to suicidal ingestion of a "look-alike" illicit drug is reported. Caffeine concentrations were determined by high pressure liquid chromatography (HPLC) with the brain having the highest level reported in the literature to date. Also, the blood concentration of caffeine was one of the highest among the cases reported. A literature review of caffeine fatalities is presented.

Adult↗
PubMedDate not supplied

Preoperative esophageal transit studies are a useful predictor of dysphagia after fundoplication.

Fundoplication performed for gastroesophageal reflux disease may be complicated by postoperative dysphagia despite successful reduction in reflux symptoms. This is more likely in those patients with reflux who have concurrent esophageal dysmotility. The aim of this study was to establish whether esophageal transit studies using a technetium-99m jello bolus (jello esophageal transit) could detect the presence of motility disorders preoperatively and hence predict surgical outcome. Transit studies in 33 healthy volunteers yielded a normal range of 2 to 24 seconds using ninety-fifth percentile distribution. In the second phase of the study, 26 patients accepted for laparoscopic fundoplication were enrolled: jello esophageal transit, manometry, and endoscopy were attempted preoperatively in all subjects. A clinical dysphagia score was assigned from a questionnaire. Six months after surgery, five patients had dysphagia and of these four were found to have abnormal preoperative jello esophageal transit, for a sensitivity of 80%. Of the 21 patients who had no dysphagia after surgery, 20 patients had normal preoperative jello esophageal transit, showing a specificity of 95%. This esophageal transit study is noninvasive, reliable, and sensitive. When performed prior to fundoplication, it appears to be of significant value in detecting a subtle functional motility disorder that predisposes to postoperative dysphagia. Jello esophageal transit may assist the surgeon in planning treatment of gastroesophageal reflux disease.

Adult↗