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Biomedical subjects

L Enerbäck

Publications and source records attributed to L Enerbäck.

At least 91 records · Page 5Linked to original sources
PubMed1979

Long term increase of mucosal mast cells in the rat induced by administration of compound 48/80.

Administration of Compound 48/80 to rats for 5 days resulted in an increase of the specific type of mucosal mast cell, while connective tissue mast cells elsewhere were almost completely degranulated. The number of mucosal mast cells increased slowly for another 5 days and then returned to the control level, in an exponential manner. The half life of the newly formed mast cells was calculated to be about 40 days. This value may be taken as an estimate of the half life of mucosal mast cells. These cells, therefore, constitute a fraction of mast cells with rapid turnover. Available evidence indicates that the classical connective tissue mast cell has a very long life span, without significant turnover in terms of cell death and cell renewal. We suggest that the increase of mucosal mast cells is an indirect effect of Compound 48/80, related to its effect on other mast cells and mediated by material(s) released from these cells during the secretory process.

Animals↗
PubMed1979

Protein content, dry mass and chemical composition of individual mast cells related to body growth.

Recently developed quantitative microscopical techniques were used to study relations between body growth and protein content as well as dry mass of individual mast cells. Since previous studies had shown an age-related increase of mast cell content of 5-hydroxytryptamine (5-HT) and heparin, these mast cell components were also included in the present study. The cells were obtained from the peritoneal cavity of rats aged 44--269 days (body weights 189--610 g). All studied mast cell parameters showed an increase that was related to the growth of the animals. The dry mass increased 60%, protein 50%, heparin 50% but 5-HT increased as much as 260% during the studied growth period. There was a mutual and linear correlation between all studied mast cell parameters. Population studies, based on large scale measurements of individual mast cells from young and adult rats, were made. These studies showed that histograms of 5-HT content, protein content and dry mass of individual mast cells were skewed with a tail towards higher values and approximately lognormal. On the other hand, the frequency distribution of heparin content of individual mast cells was approximately normal.

Animals↗
PubMed1978

Growth related changes in the content of heparin and 5-hydroxytryptamine of mast cells.

Heparin and 5-hydroxytryptamine (5-HT) were quantitated cytofluorometrically in individual mast cells from rats of various ages and body weights. Mast cells were studied in animals 35-200 days of age (150-575 g) representing a period of major body growth and about a quarter of the life span of the rat. Mast cell numbers as well as the content of both heparin and 5-HT in the mast cells was found to be strongly related to body weight and age of the animals. The number of mast cells increased about 3.5 times, the content of heparin in mast cells was doubled and the content of 5-HT increased at least three times during the growth period studied. There were great variations in the content of heparin and 5-HT within the cell populations of both young and old animals. The heparin content in the mast cell populations appeared to be either approximately normally distributed or slightly positively skewed. The skewness was not as marked as in a log-normal distribution. The 5-HT distribution profiles, on the other hand, were more strongly positively skewed. Except in the youngest age group, the 5-HT content appeared to be log-normally distributed within the mast cell population. A strong positive correlation was found between the median values of 5-HT and heparin content in the mast cell populations of growing rats.

Aging↗
PubMed1978

Cytofluorometric quantitation of 5-hydroxytryptamine and heparin in individual mast cell granules.

Cytofluorometric quantitation of 5-hydroxytryptamine (5-HT) and heparin in individual mast cell granules is described. The technique is based on micromanipulation of intact mast cells reacted with formaldehyde or stained with Berberine sulfate and the use of a cytofluorometer equipped with a sensitive peak detecting device. The quantities of 5-HT and heparin contained in mast cell granules which are of the order of 10(-16) and 10(-13) g, respectively were expressed as relative fluorescence guanta. The results of measurements on representative samples of mast cell granules indicate that all granules contain heparin as well as 5-HT, and that there are large variations in both 5-HT and heparin content within the granule populations of individual cells. A dose dependent increase in 5-HT content in both cells and individual mast cell granules occurred 24 hr after the injection of 10--50 mg L-5-hydroxytryptophan/kg intraperitoneally. There was no evidence for an increase in the heparin content of granules or cells, indicating that a new synthesis of granular macromolecules is not required for the 5-HT uptake. The results further suggest that 5-HT may be stored initially in a cytoplasmic extragranular pool and then taken up in the mast cell granules.

5-Hydroxytryptophan↗
PubMed1978

Changes in numbers and heparin content of peritoneal fluid mast cells of growing rats measured by flow cytofluorometry.

A cytofluorometric method, based on berberine staining of mast cell heparin, was used for flow cytofluorometric counting and heparin quantitation of mast cells in crude peritoneal suspensions of growing rats. The automatic flow cytofluorometric counting of mast cells correlated well with hemocytometer cell counts. The mean mast cell heparin content obtained by flow cytofluorometry showed good agreement with such obtained by cytofluorometry of microscopically identified mast cells. The number of peritoneal mast cells and the mean mast cell heparin content was found to increase as the animals grew older. The results of the microscope fluorometric measurements suggested that the heparin content was normally distributed within mast cell populations of both young and old rats. However, the heparin distributions obtained by flow cytofluorometry were often positively skewed but did not fulfill the condition of the log-normal distribution.

Aging↗
PubMed1977

Uptake of 5-hydroxytryptamine by mast cells in vivo: a cytofluorometric study of mast cells and individual mast cell granules.

Uptake, distribution and turnover of 5-Hydroxytryptamine (5-HT) was studied by cytofluorometric analysis of whole mast cells and individual granules. Injection of 5-HT as well as 5-Hydroxytryptophan (5-HTP) intraperitoneally or subcutaneously resulted in a parallel uptake of 5-HT in cells and granules. Intraperitoneal injections of 5-HT in such small quantities that may be available under physiological conditions resulted in an increase in fluorescence intensity of the mast cells, indicating a very efficient uptake mechanism for 5-HT in vivo. Much larger doses of 5-HTP were required to obtain a corresponding uptake of 5-HT in the mast cells. The 5-HT was rather rapidly taken up in the granules and eliminated very slowly, at the same rate both from granules and mast cells. The low elimination rate confirms our previous findings that the turnover of 5-HT is much lower in mast cells than in other amine containing cell systems. The combination of an extremely efficient, rapid uptake of 5-HT with a slow elimination suggests a specific function for mast cells in the regulation of free amine concentrations in tissues.

5-Hydroxytryptophan↗
PubMed1977

Cytofluorometric quantitation of 5-hydroxytryptamine in mast cells: an improved technique for the formaldehyde condensation reaction.

A simple technique for the condensation of cellular 5-hydroxytryptamine (5-HT) with formaldehyde gas is described. The technique, which is especially suited for quantitative cytofluormetric studies, involves the generation of formaldehyde gas from dry paraformaldehyde in a closed reaction vessel with the addition of a measured quantity of water. The fluorescence yield of 5-HT was tested at various humidities. Optimal results were obtained with the addition of 100 mg water to a 1000 ml reaction vessel containing 6 g of dry paraformaldehyde. A major advantage of the method if the fact that the humidity during the reaction can be precisely controlled. The fluorescence yield of 5-HT, tested over a 50 day period showed excellent reproducibility. The stoichiometry of the reaction was tested by comparison of cytofluormetic data with that obtained by analysing the 5-HT content of pooled mast cells with an independent biochemical method. A highly satisfactory correlation (r = 0.96) was obtained within the range of 0.1 to 4 pg of 5-HT per cell. The limit of sensitivity of the cytofluorometric method was found to be of the order of 10(-13) g, and was determined by the fluorescence blank of the mast cells. This contributes to between 10 and 30 per cent of the total fluorescence emission from mast cells containing about 0.2 pg of 5-HT.

Animals↗
PubMed1976

Mast cell activation and tissue cell proliferation.

The effect of mast cell activation and degranulation on the proliferation in the intact mesentery was studied in Sprague-Dawley rats. Mast cell activation was achieved by a single intraperitoneal injection of Compound 48/80. The proliferation was studied using three independent methods for estimation of cell production and DNA synthesis: 1. the mitotic index, 2. the relative number of cells having a DNA content in the S and G2 regions, by Feulgen photometric measurement in individual cells, and 3. the specific DNA activity, employing a method which combines a liquid scintillation technique after an intravenous injection of 3H-thymidine and Feulgen photometric determination of the DNA content per membrane preparation. It was found that the proliferation of the normal mesenchymal cells adjacent to the activated and degranulated mast cells in the mesentery was significantly increased within 24 and 32 h, the maximum increase being more than 20-fold compared to untreated controls. The results suggest that the common type of mast cell may have a pathophysiological function related to stimulation of local cell proliferation.

Animals↗
PubMed1976

A tissue model for the study of cell proliferation parameters in vivo.

An intact tissue model which can be used for detailed microscopic studies, quantitative cytochemical analysis and biochemical analysis has been explored, using a number of cell proliferation parameters. The preparations consist of mesenterial "windows" from rats dispersed on object slides. A technique for determining, in one and the same preparation, DNA content and mitotic activity of individual, selected cell types, and DNA synthesis in terms of incorporation of tritiated thymidine into DNA is described.

Animals↗
PubMed1976

Millisecond fading and recovery phenomena in fluorescent biological objects.

Cytofluorometric signals derived from some frequently used fluorophores were studied during illumination times in the millisecond range. These rapid signals were recorded on a storage oscilloscope. The objects studied included (1) Berberine sulphate stained mast cell heparin, (2) Acriflavine-Feulgen stained DNA, (3) Acridine orange stained mast cell heparin, (4) Acridine orange stained DNA and (5) Fluorescein isothiocyanate-conjugated IgG in an antinuclear factor test. A new rapid fading phenomenon, appearing as an initial peak upon the familiar slowly declining fluorescence signal, is reported. This fading, which had a duration of about 10 ms, also showed a very rapid recovery. The influence of this phenomenon on fluorometric measurement techniques is discussed. The millisecond fading phenomenon occurred in all the fluorophores studied except Fluorescein isothiocyanate-conjugated IgG. In the case of acridine orange the phenomenon was present when the dye was bound to nuclear DNA but absent when the dye was bound to mast cell heparin. This suggests that the millisecond fading and recovery phenomenon may be used in fluorescent microprobe studies.

Animals↗
PubMed1976

Oral acantholytic itching disease responding to dapsone. Dermatitis herpetiformis, pemphigus, or a new disease?

A patient had a blistering and severely itching disease confined solely to the oral cavity. The histopathologic findings had the features of both pemphigus and dermatitis herpetiformis. There were no gastrointestinal symptoms, no IgA could be found in uninvolved skin, and no intercellular or basement membrane antibodies were present in the serum or epidermis. The disease responded favorable to dapsone (diaminodiphenylsulfone), which could be discontinued after 2 1/2 years. The literature is briefly reviewed, and there is a discussion of whether the patient was suffering from pemphigus or dermatitis herpetiformis. The conclusion is drawn that the diagnosis cannot be established with certainty and that we are perhaps dealing with a new disease. It is stressed that in such aberrant cases a therapeutic trial with dapsone should be made.

Acantholysis↗
PubMed1976

Quantitation of mast cell heparin by flow cytofluorometry.

Mast cells can be automatically identified in a mixed cell population by flow cytofluorometry after Berberine sulphate staining. Volume specific counts of the total number of cells and number of mast cells, as well as frequency distributions of fluorescence intensities of mast cells, based on a large number of cells, can be rapidly obtained. Results obtained by microscope fluorometry of cells identified by phase contrast microscopy showviously published results it may be inferred that the fluorescence intensity of individual mast cells is proportional to mast cell heparin content. The automated cell counts correlated very well with manual hemocytometer counts. Both cell counts and the determination of mean mast cell fluorescence showed excellent reproducibility.

Animals↗
PubMed1975

A cytofluorometric and radiochemical analysis of the uptake and turnover of 5-hydroxytryptamine in mast cells.

Uptake and turnover of 5-hydroxytryptamine (5-HT) after the administration of 5-hydroxytryptophan (5-HTP) has been studied in rat peritoneal mast cells using radiochemical and quantitative cytofluorometric methods. There was a close agreement between the results obtained with the two methods. The extreme sensitivity of the cytofluorometric method was indicated by the fact that 0.2 pg 5-HT contained in mast cells from control rats could be readily quantitated. The cytofluorometric analysis demonstrated a large variation in 5-HT content of individual mast cells within the mast cell populations. The storage capacity for 5-HT greatly exceeded the amount found in normal mast cells. Intraperitoncally injected 5-HTP was rapidly taken up and eliminated from the mast cells within 12 hr, while 5-HT, probably derived from intracellular decarboxylation of 5-HTP, was retained in the cells and slowly eliminated. The elimination of 5-HT followed an exponential course and the half-life was found to be about 10 days. The results indicate that the turnover of 5-HT is much slower in mast cells than in other cells which normally store 5-HT.

5-Hydroxytryptophan↗