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Biomedical subjects

J Jansen

Publications and source records attributed to J Jansen.

At least 199 records · Page 11Linked to original sources
PubMed1986

Extradural analgesia and retinal haemorrhage in the newborn.

The incidence and severity of retinal haemorrhage were examined in 976 babies born by vaginal delivery. The influence of the method of analgesia, instrumental delivery and parity was studied. The mothers of 638 infants received extradural analgesia, while the other 338 received either narcotics or no analgesia. Extradural analgesia did not lead to a higher incidence of retinal haemorrhage, even though the number of vacuum extractions was doubled. With increasing parity, the total frequency and the frequency of severe retinal haemorrhage decreased (P less than 0.001). Severe retinal haemorrhage was not seen in any baby of whom the mother was para 4 or more.

Anesthesia, Epidural↗
PubMed1986

Prognostic significance of signs and symptoms in hydrocephalus. Analysis of survival.

An analysis of survival, using Cox's regression model, was performed on 231 patients with hydrocephalus diagnosed before age five years. Age range at follow-up was 21-35 years. The only constant covariate of prognostic importance was asphyxia with a factor of excess mortality of 1.70. Important time-dependent covariates were: a head circumference increasingly above the 97th percentile and/or a radiological diagnosis of hydrocephalus, general seizures, a short lapse of time since diagnosis, and the sign of downward-displaced eyes. The excess mortality of patients with the sign of downward-displaced eyes could not be expressed by a factor of excess mortality, because this was age-dependent. For the other time dependent covariates the factors of excess mortality were 2.5-6.3. Complications during pregnancy and at birth, sex, birth weight, and surgical treatment of those days were not significant for survival. Examples of survival functions with different values for the time-dependent covariates are given.

Adolescent↗
PubMed1986

Artificial periodontal defects and frequency of tooth brushing in beagle dogs (I). Clinical findings after creation of the defects.

This investigation was designed to determine the influence of different frequencies of tooth brushing on artificial periodontal defects in the beagle dog shortly after creation. In 12 beagle dogs, periodontal defects were created using elastic bands placed in the sulci below the gingival margin after having cut the dento-gingival fibres to the level of the alveolar bone. This active phase of creating defects lasted for 6 weeks. 6 premolars in the lower jaw were used (2P2, 3P3, 4P4). After removal of the elastic bands, the 12 dogs were distributed into 3 groups of 4 dogs each. Each group was brushed with a certain frequency, i.e., 7 times, 3 times or once a week. Plaque index, gingival index and probing depth, using a constant force probe, were assessed interproximally. The experiment lasted for 24 weeks. For hypothesis testing, a brushing effect was calculated for each dog. Furthermore, an analysis was performed based on the absolute scores at week 24. From the statistical analysis, it was concluded that in artificially-induced periodontal defects in beagle dogs immediately after creation, brushing 7 times a week is superior to brushing 3 times a week to establish and maintain gingival health.

Animals↗
PubMed1986

Gingival health and frequency of tooth brushing in the beagle dog model. Clinical findings.

The aim of this experiment was to study clinical parameters when 3 different frequencies of plaque removal were applied to healthy gingivae in the beagle dog model. The maxillary first, second and third premolars of 12 beagle dogs, at the start of the experiment 2 years of age, were, after a thorough cleaning, submitted to daily plaque removal during a pre-experimental period of 8 weeks. At the start of the experiment, the dogs were distributed into 3 groups of 4 dogs each: one group was brushed 7 times a week, a second group was brushed 3 times a week and another group was brushed only once a week. Brushing was executed over a period of 24 weeks, on the right sides of the upper jaws. The left upper jaws served as controls. At regular intervals, the plaque index, the gingival index and probing depths were assessed. A "brushing effect" was calculated for each dog, to include information on all within-dog and between dog variations. Comparison of brushing effects revealed that in this experimental model, plaque removal with a frequency of 3 times a week was sufficient to preserve gingival health, whereas tooth brushing once a week resulted in gingival inflammation. Therefore it can be concluded that 3 times a week is the critical brushing frequency in the beagle dog model with healthy gingiva at baseline.

Animals↗
PubMed1986

Artificial periodontal defects and frequency of tooth brushing in beagle dogs (II). Clinical findings after a period of healing.

This investigation was designed to determine the influence of different frequencies of tooth brushing on artificial periodontal defects in the beagle dog after a period of healing. In 12 beagle dogs, periodontal defects were created using elastic bands placed in the sulci below the gingival margin after having cut the dento-gingival fibres to the level of the alveolar bone crest. This active phase of creating defects lasted for 6 weeks. After removal of the elastic bands, the created defects were left undisturbed during the remainder of the pre-experimental period (12 weeks). 6 premolars in the lower jaw were used (2P2, 3P3, 4P4). After the pre-experimental period, the 12 dogs were distributed into 3 groups of 4 dogs each. Each group was brushed with a certain frequency, i.e., 7 times, 3 times or once a week. Registrations of plaque index, gingival index and probing depth using a constant force probe were carried out on approximal surfaces. The experiment lasted for 24 weeks. A brushing effect was calculated for each dog to include information on all within-dog and between-dog variations. It was shown in relation to artificially-induced periodontal defects in beagle dogs that after a period of healing, brushing 7 times a week is superior to brushing 3 times a week in establishing and maintaining gingival health.

Animals↗
PubMed1986

Experimental gingivitis and frequency of tooth brushing in the beagle dog model. Clinical findings.

The aim of this experiment was to study clinical parameters when 3 different frequencies of tooth brushing were applied to sites of experimental gingivitis in beagle dogs. 12 beagle dogs, at the start of the experiment 2 years of age, were used. After a thorough cleaning, the maxillary left and right first, second and third premolars were brushed daily for a period of 8 weeks. Subsequently, for 4 weeks, all brushing was omitted in order to establish an experimental gingivitis. After this pre-experimental period, the dogs were distributed into 3 groups of 4 dogs each: one group was brushed 7 times a week, a second was brushed 3 times a week and the third group was brushed only once a week. Brushing was carried out for 24 weeks, only on the right sides of the upper jaws, the left upper jaws serving as controls. At regular intervals, plaque index, gingival index and probing depths were assessed. A brushing effect was calculated for each dog, to include information on all within-dog and between-dog variations. The present study demonstrated that only by brushing every day can clinically healthy gingivae be obtained in the beagle dog model with experimental gingivitis at baseline. The state of gingival health at baseline may be used to determined the frequency of brushing necessary to create or maintain healthy gingivae.

Animals↗
PubMed1986

Alloimmune neonatal thrombocytopenia and hydrocephalus. Platelet antigen Zwa, ABO-antigens and HLA-antigens in mothers to infants with hydrocephalus.

In 27 mothers to infants with hydrocephalus determinations of platelet antigen Zwa, HLA-typing and ABO-typing were performed in order to evaluate whether undiagnosed alloimmune neonatal thrombocytopenia (AINT) could be an aetiological factor in hydrocephalus. All mothers were Zwa-positive, and the frequency of HLA-antigens and ABO-antigens was as in the normal population. Though sporadic cases of hydrocephalus following AINT are reported, this is not a common cause of intracranial haemorrhage and hydrocephalus.

ABO Blood-Group System↗
PubMed1986

What is the maximal effective dose of caerulein in stimulating pancreatic secretion in man?

The pancreatic exocrine secretory response to increasing doses of exogenous caerulein with and without a background infusion of secretin was studied in 5 healthy volunteers. Caerulein over a full range of doses (2.3-37 pmol/kg/h) produced increasing enzyme secretion up to 18.5 pmol/kg/h, whereas 37 pmol/kg/h was clearly supramaximal and caused submaximal enzyme release. We conclude that maximal pancreatic enzyme secretion is achieved with lower caerulein doses than generally used in pancreatic function tests.

Adult↗
PubMed1986

Selective removal of clonogenic neoplastic B cells from human bone marrow using anti-HLA-DQ antibodies and complement.

Polymorphic HLA-DQ (DC/MB) determinants appeared to be not expressed on human hematopoietic progenitor cells (HPC), using several murine monoclonal and human polyclonal antibodies in a complement-dependent cytotoxicity (CDC) assay. Since mature HLA-DR-positive malignant lymphoma cells prove to be HLA-DQ positive, an attempt was made to remove clonogenic neoplastic DQwl-positive B cells selectively from DQwl-positive marrow samples without affecting hematopoietic progenitor cells. Using a combination of a clonogenic tumor cell assay, an HPC culture assay, and a mixed-tumor-cell-HPC culture assay, selective elimination of more than 98% of clonogenic neoplastic cells from tumor-cell-contaminated bone marrow suspensions was achieved with monoclonal anti-DQ antibodies and complement without depletion of HPC. These results indicate that anti-HLA-DQ antibodies can be used in autologous bone marrow transplantation to deplete the bone marrow cell suspension of DQ-positive malignant cells.

Antibodies, Monoclonal↗
PubMed1986

Expression of CD11, CDw15, and transferrin receptor antigens on human hematopoietic progenitor cells.

The expression of transferrin receptor-associated antigens and of CD11 and CDw15 antigens was investigated on myeloid committed progenitor cells (CFU-GM day 10, CFU-GM day 7, and cluster-forming cells [CFC] day 4), on erythroid committed progenitor cells (BFU-E and CFU-E), and on multilineage progenitor cells (CFU-GEMM). Both complement-dependent cytotoxicity and fluorescence-activated cell-sorting assays were performed. Complement-dependent cytotoxicity appeared to be the more sensitive assay. Transferrin receptor-associated antigens appeared to be clearly present on all myeloid and erythroid committed progenitor cells, but were found to be only weakly expressed on CFU-GEMM. CD11 antigens appeared to be strongly expressed only on mature granulocytes, monocytes, and certain lymphocytes, but not significantly on myeloid committed precursor cells. Surprisingly, CD11 antigens were weakly, but significantly, present on CFU-E. CDw15 antigens appeared to be restricted to myeloid differentiation and were increasingly expressed from CFU-GM day 10 to CFC day 4. Thus, antitransferrin receptor, CD11, and CDw15 antibodies can be used to separate hematopoietic progenitor cells and may be useful tools in the study of hematopoietic differentiation.

Antibodies, Monoclonal↗
PubMed1986

Establishment in long term culture of megakaryocytic leukemia cells (EST-IU) from the marrow of a patient with leukemia and a mediastinal germ cell neoplasm.

Megakaryocytes are the bone marrow cells that generate platelets. They are relatively rare cells, comprising between 0.03 and 0.06% of all nucleated marrow cells (R. L. Berkow et al., J. Lab. Clin. Med., 103: 811-818, 1984). The study of human megakaryocyte differentiation and function has been hampered by the small number of these cells available for study. Recently we have established a human cell line (EST-IU) from the marrow of a patient with an acute nonlymphocytic leukemia and a mediastinal germ cell tumor. While this cell line seems to express many of the phenotypic characteristics of human megakaryocytes, it does not appear to express any phenotypic properties associated with cells of the erythroid, lymphoid, granulocytic, or monocytic lineages. Transmission electron microscopy demonstrates frequent multinucleated cells. Staining for platelet peroxidase reactivity revealed darkening of the perinuclear envelope and the endoplasmic reticulum, a characteristic of cells of the megakaryocytic lineage. Indirect immunofluorescence assays reveal that EST-IU expresses reactivity with anti-platelet glycoprotein antisera, anti-Factor VIII-related antigen antisera, anti-Factor V antisera, anti-thrombocyte antisera, Tab (monoclonal anti-platelet glycoprotein IIb-IIIa), and anti-fibronectin antisera. Flow cytometry-derived DNA histograms demonstrate populations with multiple ploidies, ranging from approximately 4N to 32N. Based upon morphological and histochemical characteristics, antigenic expression, and nuclear characteristics, EST-IU cells appear to have a phenotype that closely resembles human megakaryocytes. This cell line should be useful in the further cell study of the molecular and cell biology of human megakaryocytopoiesis.

Acute Disease↗
PubMed1986

Reduction and repopulation of recipient T4+ and T8+ T-lymphocytes in allogeneic bone marrow transplantation.

In eight recipients of allogeneic bone marrow grafts who had sex-mismatched donors, the reduction and subsequent repopulation of T4+ and T8+ T-lymphocytes of recipient origin were studied. The origin of the donor-recipient T4+ and T8+ T cells was studied using quinacrine staining of Y chromatin combined with T-cell typing for T4 and T8. Following chemoradiotherapy and bone marrow transplantation (BMT), T cells reached their nadir at a median of five (range 1-8) days after BMT. T8+ T cells decreased at a faster rate from the peripheral blood than T4+ T cells. The first T cells that appeared in the circulation at day 12 were predominantly T4+, and a large number of them were of recipient origin. Thereafter, they gradually decreased, and the numbers of T cells of donor origin increased. In the patients who had no or only minor complications, T4+ and T8+ T cells of donor origin repopulated the blood at similar rates. This pattern, however, was modified by severe graft-versus-host disease or by cytomegalovirus infection.

Antibodies, Monoclonal↗
PubMed1986

Reduction and repopulation of T-lymphocytes after cytoreductive therapy with or without autologous bone marrow rescue.

The reconstitution of peripheral-blood T-lymphocytes following cytoreductive therapy in standard (11 patients) or in high dosages (ten patients) was compared with that after supralethal cytoreductive therapy followed by autologous bone marrow rescue (ABMR, 20 patients). Along with the increasing cytotoxic potential of the three therapy protocols, T-cell counts fell to lower levels. Following all three forms of cytoreductive therapy, T8+ T-cell counts decreased to lower levels than T4+ T-cell counts. The greater relative reduction of T8+ T cells may indicate that T8+ T cells are more sensitive to cytoreductive therapy than T4+ T cells, and/or that T8+ T cells have shorter survival times. The contribution of residual (mainly T4+) T cells to the T-cell repopulation was significant in the patients on standard-dosage chemotherapy, less important in those on high-dosage chemotherapy, and minor in those receiving supralethal cytoreductive therapy and ABMR. The repopulation rates of T8+ T cells following ABMR exceeded those observed after chemotherapy without ABMR. The T3- (T3 negative) T-cell subset, which comprises only 5%-10% of peripheral T cells in normal individuals, decreased rapidly to low levels and remained so for the entire six-week observation period in both chemotherapy groups. Following ABMR, however, those T3- T cells rapidly increased again to normal levels. Since the T cells in bone marrow biopsies have a large T3- fraction, that rapid recovery of T3- T cells may reflect the contribution of marrow precursors in the marrow grafts to the improved T-cell regeneration following ABMR.

Adolescent↗
PubMed1986

Chemotherapy-induced acral erythema in patients receiving bone marrow transplantation.

Chemotherapy-induced acral erythema is an uncommon and distinctive syndrome of intense macular erythema of the palms and fingers seen in patients treated with high-dose chemotherapy. It is painful, may form bullae, and heals uneventfully with desquamation. The incidence (35%) of this complication in patients receiving bone marrow transplantation at our institution is quite high and probably reflects the exceptional doses of chemotherapy and concomitant total body irradiation these patients receive. Biopsy specimens showed vacuolar change, spongiosis, necrotic keratinocytes, and epidermal atypia. These findings probably result from direct toxic effect and mimic those of acute graft-vs-host disease. Awareness of chemotherapy-induced acral erythema is important to avoid its misdiagnosis as a cutaneous sign of acute graft-vs-host disease. This distinction can usually be made on clinical grounds. If necessary, serial skin biopsy specimens are helpful.

Adolescent↗
PubMed1985

Human hematopoietic progenitor cells in long-term cultures express HLA-DR antigens and lack HLA-DQ antigens.

The expression of HLA-DR antigenic determinants on human hematopoietic progenitor cells (HPC) capable of differentiating into mature blood cells, as determined in semisolid cultures, has been demonstrated previously (3-7). Here, we investigated the expression of class II determinants on HPC responsible for the sustained proliferation of colony-forming units of granulocyte/macrophage (CFU-GM), of multilineage HPC (CFU-GEMM, granulocyte/erythrocyte/macrophage/megakaryocyte), and burst-forming units of erythroid cells (BFU-E) in liquid long-term cultures. Using both fluorescence-activated cell sorting and complement-dependent cytotoxicity assays, HLA-DR determinants could be identified on virtually all these HPC capable of proliferating in long-term cultures. Experiments in which the stromal layer had been irradiated provided evidence that the HPC themselves were truly HLA-DR+, and that the sustained proliferation of HPC was not due to activation of HLA-DR- residual HPC in the stromal layer by reinoculated HLA-DR+ accessory cells. Furthermore, it was shown that all HPC recognized in semisolid and liquid long-term cultures were HLA-DQ-. These results suggest that the human true pluripotential stem cell is HLA-DR+. These results open the possibility of studying class II-dependent regulation of hematopoiesis in liquid long-term cultures.

Cell Division↗