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Biomedical subjects

J B Boezeman

Publications and source records attributed to J B Boezeman.

At least 37 records · Page 2Linked to original sources
PubMed1991

Prognostic factors in the treatment of alopecia areata with diphenylcyclopropenone.

One hundred thirty-nine patients with alopecia areata were treated with diphenylcyclopropenone. Before treatment, 85 patients had subtotal or total hair loss (greater than 90% bald area) and in the remaining patients scalp involvement was between 40% and 90%. The following three factors were found to be of prognostic significance: type of alopecia areata as documented before treatment, duration of the disease before therapy, and presence of nail changes. Other factors such as age at onset, sex, presence of atopic features, the extent of variation in the range of diphenylcyclopropenone concentrations during treatment, and sleep disturbances caused by pruritus did not influence the prognosis significantly.

Adolescent↗
PubMed1991

Effect of doxorubicin exposure on cell-cycle kinetics of human leukemia cells studied by bivariate flow cytometric measurement of 5-iodo-2-deoxyuridine incorporation and DNA content.

Cell kinetics of two human leukemic cell lines, Molt-4 and K562, following a 2-h exposure to doxorubicin, were studied. DNA flow cytometry provided static information that for both cell lines a dose-dependent accumulation occurred at the G2 + M compartment that disappeared in time. Kinetic information was provided by time-monitoring cells labeled with 5-iodo-2-deoxyuridine (IdUrd) by two-parameter flow cytometry, analyzing the IdUrd label and the DNA content. The cell-cycle time (Tc) of exponentially growing Molt-4 cells was determined to be 20 h. Twenty-four hours after a 2-h exposure to 0.25 micrograms/ml doxorubicin, the Tc had increased to 23 h; following exposure to 1.0 micrograms/ml, it increased to 33 h. Cell kinetics of K562 cells following doxorubicin exposure were monitored in time up to 4 days. The average Tc of exponentially growing K562 cells was determined to be 24.7 h. Twenty-four hours following 2-h exposure to 0.25 or 0.5 micrograms/ml doxorubicin, the Tc were determined to be 28 and 32 h, respectively. After an additional 2 days, the Tc were both determined to be 24 h. The dose-dependent, reversible cell-cycle delay that persisted at least 48 h should be taken into account as an additional mode for decrease of a (tumor) cell population doubling time after exposure to doxorubicin.

Cell Cycle↗
PubMed1990

Simultaneous measurement of DNA content and cell-surface immunofluorescence of human bone marrow cells using a single laser flow cytometer.

This paper describes the measurement of S phase DNA content in human bone marrow subpopulations using a single laser method for bivariate analysis of DNA content and cell-surface immunofluorescence (s-IF). Low density (less than 1.077 g/ml) bone marrow cells were labeled with a panel of unconjugated monoclonal antibodies (MoAb) for the lymphoid (CD2 + CD19), T-lymphoid (CD2), B-lymphoid (CD19), erythroid (anti-glycophorin-A), myelomonocytic (CD13, CD33; single and as cocktail) and monocytic (CD14) lineages. A fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse label was used as second step. Unfixed, MoAb-labeled cells were incubated for 24 h with a hypotonic propidium iodide solution for DNA staining. Cells were analysed on a single-laser flow cytometer, operating at 488 nm. The effect of the combined staining protocol upon both s-IF and DNA stainability was evaluated. Only a slight decrease (mean: 29.0%) in s-IF intensity was observed after DNA staining. The percentages of immunofluorescent cells in the bone marrow samples of 10 normal individuals before and after DNA staining were essentially unchanged for all the MoAbs used. The DNA histograms of the immunophenotypically defined subpopulations were of excellent quality with a mean coefficient or variation of 1.8%. This procedure allows the assessment of very low levels of S-phase DNA content, as measured in normal low density blood cells of 8 healthy volunteers (mean 0.07%).(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1989

Topical corticosteroids delay the proliferative response to sellotape stripping.

Tape stripping of normal human skin results in a hyperproliferative response brought about by a recruitment of resting (G0) cells. The effect of diprosone and hydrocortisone on this response was studied by flow cytometric techniques. Both corticosteroids were found to delay the appearance of the cohort of recruited cells in the S-phase, the more potent antipsoriatic (diprosone) giving the greatest delay. These data indicate that corticosteroids cause a temporary block in late G1 or an inhibition of the recruitment process itself. The model may serve for the evaluation of (future) antipsoriatic drugs.

Administration, Topical↗
PubMed1989

Flow cytometric analysis of epidermal subpopulations from normal and psoriatic skin using monoclonal antibodies against intermediate filaments.

Keratin-type intermediate filament proteins show characteristic expression in normal and pathologic epidermis. Some keratins are restricted to the basal cell layers, and others occur exclusively in the suprabasal compartment. SDS-gel-electrophoresis and immunohistochemistry are generally used for the assessment of keratin profiles and their localizations. In the present investigation, flow cytometric analysis of four different monoclonal antibodies (MAb) against intermediate filament-type proteins, in addition to measurement of relative DNA content, was performed on cell suspensions derived from lesional and clinically uninvolved skin of psoriatic patients and from skin of healthy controls. MAb Ks8.12, reacting with keratins 13 and 16, was used as a marker for hyperproliferation. Pab601 recognizes the basal cell layer(s) of human epidermis. Keratin 10 expression as a marker of keratinization was quantified with RKSE60 and the anti-vimentin MAb MVI was used as a marker for non-keratinocytes. Psoriatic skin showed significantly reduced numbers of RKSE60-positive cells and MVI-positive cells compared with normal skin. In contrast to normal skin and uninvolved skin of psoriatic patients in which only a minority of the cells were Ks8.12 positive, up to 60% of the cell population in psoriatic lesions bound with MAb. Simultaneous measurement of relative DNA content and MAb binding showed that Pab601 binding was associated with cells in S-phase and G2M-phase of the cell cycle, whereas RKSE60 and Ks8.12 binding were associated with diploid cells. Multiparameter flow cytometry allows quantitative population analysis that could lead to a better understanding of the complex mechanisms of epidermal growth control under normal and pathologic conditions.

Adult↗
PubMed1988

A rapid flow cytometric method for bivariate bromodeoxyuridine/DNA analysis using simultaneous proteolytic enzyme digestion and acid denaturation.

This report describes an immunocytochemical procedure for the simultaneous quantification of bromodeoxyuridine (BrdUrd) incorporated into cellular DNA and total DNA content in individual cells in suspension. Improvement of existing methods was achieved by combining acid denaturation and proteolytic enzyme digestion (0.2 mg/ml pepsin in 2N HCl for 30 min at room temperature). Acid denaturation preceded by enzyme digestion resulted in a large amount of debris and the occurrence of naked nuclei. In contrast, the simultaneous denaturation/protein digestion procedure did not damage the cellular structure, is rapid and reproducible, and has cell recoveries of more than 85%. Although experimental conditions were tested on human cultured keratinocytes, this method also appeared applicable to bone marrow cells and cells obtained from solid tissues.

Bone Marrow↗
PubMed1988

In vivo cellular adriamycin concentrations related to growth inhibition of normal and leukemic human bone marrow cells.

Inhibition of clonogenicity of normal and leukemic human hematopoietic progenitor cells was studied after in vivo and in vitro exposure of bone marrow to adriamycin (ADM). Flow cytometric determination of cellular ADM concentrations in blast cells, expressed in fluorescence units/cell (FU/cell), correlated well with the extent of cytotoxicity. After 2 h in vitro exposure to 500 ng ADM/ml, the ADM concentration of leukemic (n = 7) and normal (n = 4) bone marrow blast cells amounted to 231 +/- 180 and 249 +/- 53 FU/cell respectively, producing moderate decreases in clonogenicity by 44 +/- 30 and 54 +/- 27%. Exposure to 2000 ng/ml produced ADM concentrations of 1184 +/- 472 FU/cell for leukemic blast cells and 1024 +/- 281 FU/cell for normal blast cells. Inhibition of clonogenicity was 96 +/- 7% in leukemic blasts and 99 +/- 1% in normal blasts. In vivo ADM concentrations in leukemic blast cells at 1-2 h after administration were 216 +/- 98 FU/cell (n = 8 patients). This implies that inhibition of clonogenicity after administration of conventional dosages of ADM will be approx. 60-70% for both leukemic and normal bone marrow progenitor cells. Such values were noted in four patients of whom bone marrow was cultured, which was obtained shortly after ADM monotherapy.

Bone Marrow↗
PubMed1988

Recruitment of quiescent (G0) cells following epidermal injury is initiated by activation of the phosphoinositol cycle.

Under normal circumstances, the rate of production of new cells by the epidermis is rather low, but injury results in a burst of mitotic activity that continues until repair is complete. It is now recognized that most cells of the germinative population are in a resting (G0) state, and "postinjury cell renewal" is the consequence of G0 cells entering the mitotic cycle. The biochemical events triggering this process, however, are unknown. Here we show that phorbol myristate acetate (PMA) is able to induce G0 mobilization in the epidermis of the nude mouse. Further, we demonstrate that amiloride (an inhibitor of the membrane Na+-H+ pump), applied topically to human skin, abolishes almost completely the regenerative response after experimental injury. We suggest that activation of the phosphoinositol cycle may initiate recruitment of G0 cells in the epidermis.

Adult↗
PubMed1988

Active vitamin D3 does not suppress recruitment of G0 cells following injury.

The effect of topically applied active vitamin D3 on epidermal regeneration was studied in eight healthy volunteers following sellotape stripping. The mobilization of resting (Go) cells was assessed by means of DNA flow cytometry, using a narrow window in the mid-S phase to monitor the progress of the recruited cells. Although vitamin D3 was applied at a concentration exceeding the range reported to be effective in psoriasis, we were unable to find any effect of active vitamin D3 on Go mobilization in vivo.

Adult↗
PubMed1988

Synchronized growth in human epidermis following tape-stripping: its implication for cell kinetic studies.

A recent investigation of the hyperproliferative activity of human epidermis following sellotape stripping showed a wave of cell divisions with a maximal percentage of cells in mid-S phase at about 39 h after stripping. Here we present a study over the period of 52-76 h following stripping, showing a second wave of cell divisions with a maximal percentage of cells in mid-S at about 63 h. This indicates an average cell cycle time of about 23 h. Human epidermis after tape-stripping provides us with a useful model of synchronized growth, allowing us to study drug influences on cell kinetics accurately.

Cell Cycle↗
PubMed1987

Cellular and plasma adriamycin concentrations in long-term infusion therapy of leukemia patients.

To determine whether long-term adriamycin (ADM) infusions resulted in cellular ADM concentrations at least comparable to those observed after bolus injections, ADM cellular and plasma concentrations were measured in 18 patients with leukemia. ADM was administered at 30 mg/m2 per day for 3 days, either as bolus injections or as 4-, 8-, or 72-h infusions. Negligible accumulation of plasma ADM was observed. Peak plasma ADM concentrations after bolus injections were 1640 +/- 470 ng/ml (n = 7). Maximum levels were 176 +/- 34 ng/ml during 4-h infusion (n = 5); 85 +/- 50 ng/ml during 8-h infusion (n = 4); and 47 +/- 5 ng/ml (n = 2) after 72-h infusion. ADM concentrations in nucleated blood and bone marrow cells correlated well (r = 0.82, n = 47). ADM accumulated in leukemic cells up to 30-100 times the plasma concentrations. The shorter the administration time-span, the higher the peak leukemic cell concentration and the greater the loss of drug immediately after the end of the administration. The final cellular ADM half-life was approximately 85-110 h. After long-term infusion and bolus injection of the same dose, similar areas under the curve for plasma or leukemic blast cell ADM concentrations were attained. Since comparable therapeutic efficacy was observed in all regimens, the antileukemic effect appeared not to be related to the peak plasma concentrations, while acute toxicity phenomena decreased with increasing duration of the infusion. Long-term ADM infusion deserves more attention in the treatment of patients with anthracyclines.

Adolescent↗
PubMed1987

Leukemic cell and plasma daunomycin concentrations after bolus injection and 72 h infusion.

The effect of the duration of daunomycin (DNM) infusion on leukemic cell drug concentrations was evaluated. Cellular and plasma DNM concentrations were measured in 20 patients with acute non-lymphocytic leukemia. DNM 45 mg/m2 was administered either as a bolus injection or as a 4-, 8- or 72-h constant-rate infusion during 3 consecutive days. Peak plasma DNM levels amounted to 227 +/- 116 ng/ml after bolus injection and were only 16 +/- 6 ng/ml after 72-h DNM infusions. Terminal plasma DNM half-lives were 14 +/- 4 h. Peak leukemic cell DNM concentrations at the 3rd day of administration were 16810 +/- 2580 ng/10(9) cells (bolus injections) and 10310 +/- 5510 ng/10(9) cells (72-h infusions). The areas under the cellular curve were similar and independent of the duration of the DNM infusion. Peak leukemic cell daunomycinol (DNMol) concentrations were respectively 3500 +/- 1600 ng/10(9) cells and 2850 +/- 1720 ng/10(9) cells. Cellular DNM terminal half-life was 13 +/- 4 h. DNM concentrations in nucleated blood and bone marrow cells correlated well (r = 0.93, n = 26). Long-term infusion produced less severe side effects. Therapeutic efficacy was maintained during long-term infusion.

Adolescent↗
PubMed1987

Flow cytometric analysis of the recruitment of G0 cells in human epidermis in vivo following tape stripping.

Tape stripping of human skin elicits a proliferative response of a synchronously-dividing group of cells. The progress of this cohort of cells has been monitored using two windows in the cell cycle, one located in mid-S phase and the other centred around G2 + M. The cellular DNA is measured with flow cytometry, the windows are defined by two ranges in the DNA histogram. The cohort can be described as the recruitment of cells from a pre-existing G0 compartment which consists of 76% of all proliferative cells. The duration of the S phase is calculated to be 10.2 hr and G2 + M phase 5.1 hr. The cell cycle time of 39 hr for normal human keratinocytes derived from these figures is in line with recent values obtained by different techniques.

DNA↗
PubMed1986

Cellular and plasma pharmacokinetics of weekly 20-mg 4'-epi-adriamycin bolus injection in patients with advanced breast carcinoma.

Weekly low-dose injections of 20 mg 4'-epi-adriamycin (E-ADM) were given to 12 patients with advanced postmenopausal breast cancer for at least 8 weeks. In advance, all patients were given hormonal therapy and polychemotherapy not containing anthracyclines. E-ADM concentrations in plasma and urine and in blood and bone marrow cells were determined during 8 consecutive weeks. Plasma concentrations in the range of a few nanograms per milliliter were seen up to 72-96 h. Cellular concentrations appeared to be more than 100-fold the plasma concentrations, and were 190 +/- 66 ng/10(9) cells on day 8, before the next injection was given. Nevertheless, no serious bone marrow toxicity was observed. In two patients with an increased plasma bilirubin concentration, cellular E-ADM concentrations were 20%-40% higher than those observed in the other patients. Plasma concentrations of E-ADM and 4'-epi-adriamycinol showed terminal half-lives 2-3 times longer and could be followed throughout the week. In three patients biopsies of skin metastases were examined. In two patients E-ADM could be demonstrated in the tumor tissue up to 7 days after the last injection. Although the number of patients investigated is too small to relate the drug kinetics to clinical response, it is of interest that the two patients with the highest cellular E-ADM concentrations responded better than the others.

Adult↗
PubMed1986

Frequency of moles as a key to melanoma incidence?

Subjects with light skin complexion are especially prone to develop melanoma. Furthermore, individuals with large numbers of moles are also at increased risk of developing melanoma. We studied the association between these two markers of melanoma in a group of healthy white people: 116 children 6 to 9 years of age, 78 children 10 to 13 years of age, and 133 medical and nursing students 18 to 30 years of age. Moles were counted on the chest, back, and lower legs. Skin complexion was established with the use of a scoring system based on burning/tanning ability, eye and hair color, and freckling tendency. A multifactorial statistical analysis was performed. Average mole counts increased with age (p less than 0.0001). Male subjects had more nevi on the trunk than female subjects, whereas counts on the lower legs were higher in female than in male subjects (p = 0.0001). Skin complexion was an important denominator of mole proneness; subjects with a light complexion had higher mean counts than those with a dark complexion (p = 0.0001). The present study shows that a significant association exists between skin complexion phenotype and numbers of moles. The pattern of the appearance of pigmented nevi roughly correlates with the sex and site distribution of melanoma.

Adolescent↗