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Biomedical subjects

C F Bassøe

Publications and source records attributed to C F Bassøe.

At least 19 recordsLinked to original sources

Concurrent measurement of antigen- and antibody-dependent oxidative burst and phagocytosis in monocytes and neutrophils.

The current study aims to review flow cytometric (FCM) parameters for the quantification of phagocytosis. A limitation of existing methods is their difficulty with accurate quantification of the phagocytic index, i.e., number of beads per phagocyte, in individual cell lines in mixed cell suspensions. We have quantified phagocytosis and the oxidative burst simultaneously using fluorescent beads coated with meningococcal outer membrane vesicles (OMV beads) by the conversion of dihydrorhodamine 123 (DHR-123) to rhodamine 123 (R-123). Both these processes depend on specific serum opsonins. After the incubation, staining with a fluorescent anti-CD14 monoclonal antibody succeeded in discriminating phagocytosing monocytes from neutrophils. The spectral overlaps between OMV beads, R-123, and anti-CD14 could be completely compensated. Percentage of phagocytosis and the phagocytic index were similar in monocytes and neutrophils, but the oxidative burst behaved differently. Two monocyte subpopulations were observed. Both subpopulations spontaneously converted some DHR-123 into R-123, whereas the reaction was triggered by phagocytosis in neutrophils. The total oxidative response increased with increasing phagocytic index in both cell types, but the oxidative burst in monocytes was about twice that of neutrophils. The oxidative ratio (mean R-123 fluorescence value divided by the phagocytic index) declined with time in monocytes, but increased in neutrophils. Our results demonstrate the need for careful attention to technical details. This single-laser, three-color FCM method facilitates the comparative research of phagocytosis and the oxidative burst in monocytes and neutrophils and provides a basis for a number of applications in hematology, infectious medicine, and immunology.

Antibodies, Monoclonal↗

Mental mobilization processes in critical incident stress situations.

In this article, the psychological emergency mobilization process that takes place in threat situations is postulated. Mental mobilization is the increased mental capability of the mind in critical situations to process incoming and stored information to enable adaptive survival responses. The processes that are mobilized in the service of survival are enhanced sensory awareness, focused attention, rapid processing of incoming data, and use of previous experience, enhanced memory, altered time perception, and temporary deactivation of emotional reactions. From a clinical standpoint, it is important that the survival value of these processes is understood, as survivors can be helped to feel a sense of accomplishment and empowerment when they are taken through a critical situation in a detailed way and discover that they have been able to function well and survive by use of their stored "experience," rapid processing of information or other aspects of their mental mobilization.

Adaptation, Psychological↗

Functional differentiation of acute myeloid leukaemia blast cells.

Little is known of the functional status of blast cells from patients with acute myeloid leukaemia (AML). We have studied phagocytosis and membrane receptors by flow cytometry (FCM), and secretory activities in blast cells from 24 AML patients prior to treatment. Blast cells from 11/16 patients attached N. meningitidis, and internalization occurred in 7/14. The phagocytosis of zymosan particles and N. meningitidis correlated linearly (r = 0.9, p<0.01, n = 11). Surface membrane expression of CD32 and CD11b was sufficient to account for opsonin-dependent attachment in all except one patient. A significant fraction of the blast cells attached, but did not internalize meningococci. CD32 and CD11b were non-functional in all the blasts from five patients, and in a subpopulation from seven additional patients. Significantly more large than small blasts expressed CD32, CD35 and CD11b (p<0.001). Phagocytosis was unrelated to the secretion of IL-1alpha, IL-1beta, and TNFalpha. In conclusion, AML blast cell function is related to receptor expression, cell size and granularity, and to FAB-type.

Adult↗

Flow cytometric quantitation of human opsonin-dependent phagocytosis and oxidative burst responses to meningococcal antigens.

A one-step flow cytometric (FCM) assay has been developed to quantify both opsonin- and antigen-dependent phagocytosis and intraphagocyte oxidative burst responses. Meningococcal outer membrane structures (OMV) were adsorbed to fluorescent polystyrene beads, opsonized with serum, and exposed to leukocytes. FCM parameters of phagocytosis were evaluated in combinations with oxidative burst indicators. Rhodamine-123 was the most sensitive indicator and was compatible with quantitation of phagocytosis. The phagocytosis and oxidative burst responses induced by OMV beads were dependent on both antigens and opsonins. Increased human opsonic responses against OMV were induced during clinical meningococcal disease. A dissociation was noted between phagocytosis and oxidative burst in individual cells, indicating that functional opsonins against OMV components may differ in their ability to stimulate phagocytosis and oxidative burst responses. The method facilitates evaluation of purified bacterial structures as mediators of opsonin-dependent phagocytosis and intracellular oxidative microbicidal mechanisms, which is of interest in the complex process of selecting bacterial antigens as constituents of certain vaccines.

Adult↗

Ribosomal proteins sustain morphology, function and phenotype in acute myeloid leukemia blasts.

Translation of mRNA is a prerequisite for cell proliferation, differentiation and viability. We have studied the effect of ribosome protein factors (GPRE) on acute myeloid leukemia (AML) blast cells. Ribosomes were isolated from MPC-11 cells using ultra-centrifugation. GPRE were extracted using a high KCl procedure. Blast cells from six AML patients were grown in suspension cultures for 24 and 96 h. GPRE or granulocyte macrophage-colony stimulating factor (GM-CSF) were added at the start of the incubation. GPRE, but not GM-CSF, prevented chromatin condensation and fragmentation of blast cell nuclei in AML-M2, -M4 and -M5 and the loss of nucleoli in AML-M2 and -M5. The fraction of phagocytosing blast cells in AML-M1, -M2, -M4 and -M5 was increased by GPRE. GPRE stimulated opsonin-dependent and -independent attachment and internalisation of N. meningitidis. GPRE increased the fraction of blasts expressing CD11b and CD32 in AML-M2 and -M5. GPRE diminished the fraction of AML-M5 cells bearing CD35 and CD32. GPRE also decreased the fraction of CD11c-bearing AML-M2 and -M5 cells. GM-CSF potentiated effects of GPRE in AML-M1, -M2, -M4 and -M5. GPRE and GM-CSF in combination affected phagocytosis and surface antigen expression in blast cells that were not influenced by either factor alone. Neither GPRE nor GM-CSF induced terminal differentiation or DNA-synthesis. We conclude that GPRE affects AML blast cell morphology, function and surface molecule expression, possibly by inhibiting apoptosis. The effects of GPRE may be mediated by ribosomal proteins that regulate translation and modulate the subcellular distribution of mRNA species.

Acute Disease↗

Functional assays for evaluation of serogroup B meningococcal structures as mediators of human opsonophagocytosis.

Functional flow cytometry and chemiluminescence (CL) assays have been modified to identify serogroup B meningococcal structures that mediate anti-meningococcal opsonophagocytosis. Serogroup B meningococcal outer membrane vesicles (OMV) were adsorbed to fluorescent latex beads (OMV-beads) and opsonized with acute phase and convalescence sera from patients with serogroup B meningococcal disease. Phagocytosis of these beads by human monocytes and polymorphonuclear leukocytes (non-lymphocytes) was dependent on both antigen exposure on the bead surface and on serum opsonization. OMV-beads opsonized with serum from a patient recovering from meningococcal disease, caused 97% of the non-lymphocytes to phagocytose an average of 15.8 beads per cell with a CL response of 46,550 mVs, whereas opsonized control beads were phagocytosed by 19% of the non-lymphocytes with 1.1 beads per cell and a CL response of 53 mVs. Increased amounts of functional, anti-OMV opsonins were detected during infection, and opsonized OMV-beads elicited phagocyte responses of similar magnitude to those of opsonized whole meningococci. Phagocyte internalization of OMV-beads was confirmed by confocal laser scanning microscopy. We conclude that epitopes on the meningococcal outer membrane are recognized by anti-meningococcal opsonins in these functional phagocytosis assays, which provide a basis for subsequent evaluation of various purified bacterial components as mediators of human opsonophagocytic responses and hence future vaccine constituents.

Antigens, Bacterial↗

Effects of interleukin 10 on blast cells derived from patients with acute myelogenous leukemia.

The effect of interleukin 10 (IL-10) on proliferation and cytokine secretion by acute myelogenous leukemia (AML) blast cells was investigated in vitro. IL-10 inhibited spontaneous AML blast proliferation for a majority of patients, whereas in the presence of exogenous growth factors (granulocyte-stimulating factor, G-CSF; granulocyte-macrophage colony-stimulating factor, GM-CSF; interleukin 3) the IL-10 effect on blast proliferation showed a wide variation depending on the individual AML patient. IL-10 seemed to cause an irreversible inhibitory effect on AML blasts, as inhibition could also be demonstrated when IL-10 was present only during the initial preincubation of the leukemia cells. IL-10 also inhibited AML blast colony formation. However, independent of the effect on AML blast proliferation, IL-10 decrease cytokine secretion from AML blast cells for all patients, as demonstrated for IL-1 alpha, IL-1 beta, tumor necrosis factor-alpha, GM-CSF and interleukin 6. IL-10 did not inhibit development of apoptosis in AML blasts cultured in vitro. Expression of complement receptors and capability to adhere and internalize bacteria by AML blasts were not altered by IL-10.

Aged↗

The skinache syndrome.

Chronic pain of unknown aetiology, and characterized by cutaneous trigger points, has been coined the skinache syndrome. The treatment of the skinache syndrome was evaluated in 94 patients by two independent methods 2 years after treatment. After one subcutaneous injection of lidocaine 68% of the patients were cured. The pain recurred in 27 patients having suffered for an average of 2 years. Surgical removal of the cutaneous trigger points cured 77% of the latter patients. The odds ratio of success of surgical treatment versus all other treatments combined was 101.3. The skinache syndrome requires a precise clinical investigation. Even when the origin of the pain in tendons, muscle and adipose tissue is excluded, the skinache syndrome remains a common, debilitating disorder. In contrast to fibromyalgia, the skinache syndrome has a simple and effective cure.

Aged↗

[Automatic text analysis of medical records].

Clinical narratives stored in a computerized medical record (PROMED) were automatically analyzed by a computer program (LOGSTORY). No medical knowledge was built into LOGSTORY prior to the analysis. The clinical sample consisted of 5,041 patients and 14,323 diagnoses. The present study concerns 375 diagnoses from general practice and 160 diagnoses from occupational medicine. LOGSTORY reproduced the symptoms, signs, laboratory investigations, anatomy and etiology of diabetes mellitus, obesity and lung diseases. Similarities and differences between the clinical states were automatically recognized and quantified. The extraction of knowledge from the clinical narratives required a problem-oriented medical record. PROMED-LOGSTORY may be useful for self-evaluation, peer review, quality control and research.

Expert Systems↗

[Standardization of medical forms in health care].

In the Norwegian health care system, resources worth several 100 millions of US dollars are tied up in traditional routines for handling forms. A standard form, combined with computer record systems, could potentially release a considerable share of these resources for alternative uses. Universal Form Medicine (UFM) has been used by Norwegian general practitioners since 1985. The Universal Form Medicine has been a stable standard, and replaces more than 95% of all health forms. Today, about 50% of all doctors with a computerized medical record system can use this standard form. From most aspects, the Universal Form Medicine has advantages over preprinted forms, and can be adapted to silent printers. To our knowledge, no other countries have taken the advantage of standardizing their medical forms.

Family Practice↗

Semantic analysis of medical records.

A program (LogStory) is described that was developed for the automatic semantic analysis of clinical narratives, stored in a computerized problem-oriented medical record (PROMED). The diagnoses were written in a free-text format during consultation, and later collected into diagnostic classes, e.g., diseases. A lexical parser automatically created dictionaries from the clinical narrative associated with each disease. Automatic (fuzzy) set operations were performed on the words associated with each class. The manifestations of 16 diseases were automatically extracted by pairwise operations on the word sets. The correlation between diseases and corresponding signs, symptoms and treatment was highly significant (p < 0.001). Applying the difference operation on diseases with disjunct sets of clinical findings allowed the recovery of disease-specific knowledge. The evolution of a disease was accounted for, and the system was able to generalize its findings. The PROMED-LogStory concept enables the processing of natural language and may be a powerful tool for knowledge acquisition and clinical research.

Expert Systems↗

The influence of the host on the course of gastric carcinoma.

Immunoglobulins (Ig) and some complement components (C) were quantified in sera from patients with gastric carcinoma before surgery and at regular intervals during a 5-year follow-up. The preoperative concentrations of C1-INH and C4 were higher (P < 0.0005 and P < 0.005) and IgG lower (P < 0.0005) in 50 patients with recurrence than in 46 5-year survivors. The prognostic significant of C1-INH was superior to that of the extent of disease (F-values 37.1 and 26.1). The preoperative immune data classified 76% of the patients correctly as to recurrence and no recurrence. Also, the preoperative C1-INH concentration had a highly significant effect on time to recurrence of cancer (P = 0.0007), adjusting for age and disease extent. After surgery the mean IgG concentrations were within normal range and without difference between the two groups. On the other hand, the concentrations of C1-INH and C4 in the individual patients in both groups remained the same from before to after surgery and throughout the observation period (P = 0.34). Apparently, the serum levels of C1-INH and C4 do not reflect the bearing of cancer. We therefore suggest that these variables represent an independent immune state that is appropriate to the host. A comparison of our variables with those of healthy individuals seems to support this idea. This immune state has a significant influence on whether a resected gastric cancer will recur, and also on how soon recurrence may be manifest.

Adult↗

Protein factors in extracts of ribosomes isolated from L-929 cells during various phases of the cell cycle.

Centrifugal elutriation has been utilized in order to separate cultures of L-929 fibroblasts into subpopulations containing cells at different stages of the cell cycle. The subpopulations were characterized by Coulter counter volume determination, [3H]thymidine label into DNA and flow cytometry. When a population of early G1 cells was returned to roller culture it was shown to progress through the cell cycle in a synchronous manner. Ribosomal factor extracts were prepared from cells at various phases during the cell cycle. The amounts of protein in the extracts varied greatly, being lowest in early G1 phase and showing a peak during S phase. Polyacrylamide gel electrophoresis demonstrated that there were differences in the protein species present in the extracts. Some proteins were present in the same amounts throughout the cell cycle, whereas others appeared to show a form of cyclical behaviour.

Animals↗