Biomedical subjects

S Eneström

Publications and source records attributed to S Eneström.

At least 19 recordsLinked to original sources

PubMed1995

Resin embedding for quantitative immunoelectron microscopy. A comparative computerized image analysis.

Quantitative immunoelectron microscopy (QIEM) is dependent on the reliability of preparative techniques for both efficient immunolabeling and consistent quantitative results among series of immunostained sections. The present study compared Lowicryl K4M and Epon embedding after identical fixation and dehydration of rat somatotrophic secretory granules. Labeling intensity, diameter, roundness, uptake of uranyl acetate, and gray value were measured with computer assisted image analysis. Lowicryl-embedded granules showed the highest labeling densities after conventional fixation and Progressively Lowering Temperature (PLT) dehydration, but values were not consistent in a series of immunostained sections. A lower but more uniform level of immunostaining was seen in Epon-embedded sections when tissue was cryofixed and physically dehydrated. Gray value measurements from micrographs from both embedding media confirmed the better contrast of Epon sections and the different reliefs of the granule surfaces. This study emphasizes the importance of complete comparisons of preparative techniques for QIEM for reliability and reproducibility.

Animals↗

PubMed1992

Dose-response studies in murine mercury-induced autoimmunity and immune-complex disease.

Female SJL/N mice were given either 5.0, 2.5, 1.25, or 0.625 mg mercuric chloride per liter drinking water (ppm HgCl2). Serum antinucleolar antibodies (ANuA) of the IgG class were seen in mice given at least 1.25 ppm HgCl2 for 10 weeks, a dose which corresponded to a mean renal mercury concentration, as measured with atomic absorption spectrophotometry, of 2.4 +/- 0.43 microgram Hg/g wet weight (ppm Hg; means +/- 1 SD). At a dose of 5.0 ppm HgCl2 all mice showed IgG ANuA with a mean titer of 1:846 and a mean renal mercury concentration of 14.8 +/- 3.9 ppm. Significantly increased titers of granular IgG deposits, corresponding to immune-complex (IC) deposits, developed in the renal mesangium of mice given 5.0 ppm HgCl2. Mice with heavy mesangial IgG deposits showed a mild glomerular endocapillary cell proliferation and widening of the mesangium. Renal vessel wall IgG deposits were found only in mice given 5.0 ppm HgCl2, whereas such deposits were seen in splenic and cardiac arteries of mice receiving 1.25 ppm or more of HgCl2. The renal and splenic mercury concentration was significantly increased in all groups of mercuric chloride-exposed mice and correlated with the dose. We conclude that 10 weeks peroral treatment with mercuric chloride in drinking water is able to elicit autoimmunity and IC disease in genetically homogeneous, mercury-sensitive mice at a body burden similar to that reported in some occupationally exposed humans.

Administration, Oral↗

PubMed1992

Murine susceptibility to mercury. I. Autoantibody profiles and systemic immune deposits in inbred, congenic, and intra-H-2 recombinant strains.

Inbred, congenic, and intra-H-2-recombinant mouse strains were given subcutaneous injections of either 1.6 mg HgCl2/kg body wt or 0.1 ml NaCl thrice weekly for 5-6 weeks. Mercury-treated mice from strains carrying the H-2s haplotype developed antinucleolar antibodies (ANoA), which targeted the 34-kDa nucleolar protein fibrillarin, and in some instances also nucleolar proteins of 60-70 and 10-15 kDa, the latter corresponding to histones. Strains with H-2b and H-2d haplotypes were resistant to induction of ANoA. The susceptibility to development of AnoA/antifibrillarin antibodies (AFA) was mapped to the H-2A-region using intra-H-2-recombinant strains. We were not able to confirm earlier reports that expression of H-2E genes dampens the development of ANoA. Mercury treatment caused a substantial increase in the titer of antichromatin (ACA) and/or antihistone (AHA) antibodies in a fraction of SJL/J, A.SW, A.TH, B10.S, and B10.HTT mice (H-2s), and in A/J (H-2k) mice, whereas mice from the C57BL/6J and C57BL/10J (H-2b), and the DBA and BALB/c (H-2d) strains were low or nonresponders. The development of AHA and ACA could not be linked to the H-2 complex. A significant, substantial increase of granular mesangial and systemic vessel wall IgG deposits occurred in mice with serum ANoA/AFA. However, the B10.S(9R) and B10.HTT strains, which express the H-2E genes, developed only an intermediately increased titer of mesangial IgG deposits. Systemic vessel wall IgG deposits occurred in only 60-80% of the B10.S(9R) mice and in none of the B10.HTT mice. This contrasted with the high titer of mesangial IgG deposits and uniform development of systemic vessel wall IgG deposits observed in B10.S mice not expressing H-2E. Mice with mesangial IgG deposits showed a mild glomerulonephritis. There was no systemic vasculitis. The susceptibility to development of ANoA, AHA, ACA, and systemic, granular IgG deposits in the B10.S strain was influenced by the sex, since males showed less uniform development of these immunopathologic features than females.

Animals↗

PubMed1992

Autoantibodies to leucocyte antigens in hydralazine-associated nephritis.

Clinical and laboratory findings and drug history were studied in 17 patients with suspected hydralazine-associated nephritis, five of whom only had renal disease, while twelve also had extrarenal manifestations. Renal biopsies revealed extracapillary proliferative or focal segmental proliferative glomerulonephritis in 10 patients, and tubulo-interstitial nephritis in five patients. Antinuclear antibody (ANA) was found in 16 patients, but none of the 14 patients tested had antibodies to DNA. Tests for antibodies to myeloperoxidase (anti-MPO) and antibodies to neutrophil cytoplasm antigen (ANCA) were performed by ELISA. Twelve of the 14 patients tested had anti-MPO; five of these 14 patients had ANCA, while one had borderline levels. These findings suggest that hydralazine facilitates the induction of a systemic disease with multiple autoantibody production.

Antibodies, Antinuclear↗

PubMed1992

Epon resin infiltration and immunogold labelling of pituitary secretory granules after cryofixation versus chemical fixation.

The degree of infiltration of epoxy resin into pituitary secretory granules was evaluated using X-ray microanalysis of the concentrations of chlorine in the epoxy resins. The effectiveness of infiltration was tested after three different tissue preparation techniques: cryofixation+freeze-drying (CF-FD), glutaraldehyde fixation (GF)+chemical dehydration, and no fixation--no dehydration. Signs of marked incomplete infiltration were found in embedded unfixed tissue while the other two techniques showed 80% infiltration. Uneven penetration was seen after CF-FD and GF. The plastic surface demonstrated a mountain-like appearance over the secretory granules after immunocytochemistry of the glutaraldehyde fixed tissue, whereas the CF-FD tissue showed a less furrowed surface. This probably is due to contact with water, which swells those parts of the granules that are unprotected by the plastic embedding medium. Our findings may explain why it is possible to perform immunocytochemistry on Epon embedded tissue.

Animals↗

PubMed1992

Short fixation-shock freezing and freeze-drying versus chemical fixation and dehydration: computer assisted image analysis of morphological variables and immunogold labeling density on pituitary secretory granules.

We have performed a computer assisted image analysis evaluation of the effects of two preparation protocols on morphological variables and immunolabeling density of secretory granules using rat adenohypophysis as a model. Glutaraldehyde (GA) fixation for 2 hr and chemical dehydration was compared with short GA fixation (15 min) followed by cryofixation and freeze-drying (CF-FD). The 2 hr GA fixed specimens showed spherical nuclei and secretory granules regardless of their size, contrasting with the more irregularly shaped nuclei and secretory granules after short GA-CF-FD. In the latter group of specimens a correlation could be found between smaller nuclear areas and more irregular shapes. The differences in morphological variables between the two preparation protocols might be due to a better protein stabilization and a reduced collapse of macromolecules after the 2 hr GA fixation, strengthened by the chemical dehydration. The specific immunolabeling with antiserum to growth hormone was much greater but more varied after short time GA-CF-FD than after long GA fixation. Epon surface topography over the granule area also differed: smooth after short time GA-CF-FD and furrowed after long GA fixation. Our results, demonstrating important differences in morphological parameters and immunolabeling density between two common preparation protocols, seem critical for more reliable interpretation in quantitative immunoelectron microscopy. We also emphasize the need for computer assisted image analysis and measurements in immunoelectron microscopy to ensure objective evaluations.

Animals↗

PubMed1991

Small intestinal peptidases and disaccharidases in rats with acute uremia.

Acute uremia was induced in rats with temporary clamping of the left renal pedicle and contralateral nephrectomy. Jejunal peptidase activities (aminopeptidase N, dipeptidyl peptidase IV and aminopeptidase A), disaccharidase activities (maltase, sucrase, lactase and trehalase) and morphology were studied. A significant (p less than 0.05) increase in aminopeptidase N activity and a positive correlation between aminopeptidase N activity and serum urea was found in the uremic rats. The other peptidase activities showed a slight increase in the uremic rats. A shortening of the microvilli of the small intestinal epithelial cells in the uremic rats was seen by electron microscopy. The disaccharidase activities was unaltered. This study shows the presence of functional alterations in the small intestine in rats with acute uremia. The observations are also compatible with different regulation mechanisms for the brush border peptidases and disaccharidases.

Acute Disease↗

PubMed1991

Pituitary secretory granule topography: influence of different electron microscopic preparation procedures on the surface of Epon sections.

Human, rat and mouse pituitary tissues have been examined electron microscopically in transmission (TEM), scanning-transmission (STEM) and scanning (SEM) modes for the surface appearance of the secretory granules in tissue sections. Cryofixed and cryosectioned tissue showed only slightly protruding granule profiles which had a smooth surface. Cryofixed, freeze-dried and Epon embedded pituitaries, on the other hand, demonstrated swollen and furrowed surfaces over the granules after contact with water. This topography could also be seen after glutaraldehyde fixation but less after post-fixation in OsO4. The surface alterations in the sections of pituitary secretory granules are thought to be due to differences in the homogeneity of the resin infiltration, leaving resin-free openings where water can enter. It also seems probable that the Epon resin is more influenced by water than has been previously assumed, based on the findings of efficient elimination of osmium from the granules after incubation of tissue sections in water for only 10 min.

Animals↗

PubMed1990

Arrhythmogenic right ventricular dysplasia in brother and sister: is it related to myocarditis?

Two cases of arrhythmogenic right ventricular dysplasia (ARVD) in siblings are reported. In the boy, 14 years old, the clinical history, ECG, echocardiography, and histopathological findings were consistent with ARVD. Premature ventricular contractions of left bundle branch block (LBBB) pattern were recorded but no ventricular tachycardia (VT). A high titer against mycoplasma and increased concentrations of immunoglobulins were found. Two years after his first admission he died suddenly. Autopsy revealed severe right ventricular (RV) myocardial damage, with fat cell infiltration and collagenous tissue. His sister presented with sustained VT of LBBB pattern 2 years later, at 12 years of age. Vaccination against rubella and signs of upper respiratory illness had preceded the symptoms. During the following 9 days ECGs and serum enzymes indicated the development of left ventricular (LV) infarction. Echocardiography revealed an enlarged RV and a normal LV. After 6 weeks both RV and LV showed akinetic areas and sacculations. We suggest that myocarditis may be a precipitating factor in ARVD, and perhaps the prerequisite for its manifestation.

Adolescent↗

PubMed1990

Quantitative ultrastructural immunocytochemistry using a computerized image analysis system.

Secretory granules in human pituitary adenoma cells have been examined indirectly for hormone epitopes by immunogold labelling of resin-embedded ultrathin sections. The specific binding of different immunoglobulin-gold complexes to the antigrowth hormone antibodies over the secretory granules was measured using a computerized image analysis system. This facilitated the assessment of the preferential binding to the target granules of gold particles with three different average particle diameters (Au7, Au11, Au17). The time of pretreatment of sections with H2O2 or a buffer was found to influence the staining considerably. The scanning electron microscopic findings of protruded secretory granules with a mountain-like surface might be relevant to the uneven distribution of immunolabels seen over the secretory granules in the adenohypophysis.

Adenoma↗

PubMed1990

Membranous glomerulonephritis induced by 2-mercaptopropionylglycine (2-MPG).

Thirty-two patients suffering from cystinuria were treated with 2-mercaptopropionylglycine (2-MPG) for 0.5-10 years (average 6.3 years). After 4-14 months of treatment at daily doses ranging from 500 to 2500 mg, three patients developed slight to moderate proteinuria. Two patients were subjected to renal biopsy which showed membranous glomerulonephritis. In one biopsy signs of progressive glomerular lesions were observed. In seven patients (22%) antinuclear antibodies were demonstrated. In one patient with biopsy-proven membranous glomerulonephritis, the antinuclear antibodies consisted of antihistone antibodies. The observations presented in this report indicate that 2-MPG, like D-penicillamine, could induce autoimmune reactions, in some cases leading to membranous glomerulonephritis. The prognosis seemed to be favorable. However, the occurrence of irreversible glomerular lesions as reported by us should be borne in mind when considering long-term treatment with 2-MPG. A continuous, close follow-up of patients on 2-MPG treatment is recommended.

Antibodies, Antinuclear↗

PubMed1989

Murine mercury-induced immune-complex disease: effect of cyclophosphamide treatment and importance of T-cells.

The renal immune-complex (IC) disease induced in BALB/c mice by subcutaneous injection of mercuric chloride (1.6 mg/kg b.w.) every third day for 8 weeks was prevented by the intraperitoneal injection of cyclophosphamide (20 mg/kg b.w.) 24 h prior to mercury injection. The importance of T-cells in the induction of immune-complex disease was studied. BALB/c mice given drinking water containing 20 mg/l of HgCl2 for 10 weeks showed an increased titre of granular, mesangial IgG deposits and vessel wall IgG deposits. Identically treated, congenic nude BALB/c mice with a similar body burden of mercury developed no IC-disease. Cytophotometric analysis of the T-cell subsets in subcutaneously mercury-treated mice revealed a decrease in the fraction of T-helper (L3T4+) splenic cells in the SJL and C57BL/6J strains; no significant change in the T-cell subsets was found in BALB/c mice. C57BL/6J mice, resistant to induction of IC-disease by mercury, showed no increase in the fraction of T-suppressor/cytotoxic (Lyt-2+) cells and no change in the T-helper/T-suppressor cell ratio. C57BL/6J mice could not be rendered susceptible to mercury-induced IC-disease by treatment with different doses of cyclophosphamide.

Animals↗

PubMed1989

Circulating and tissue immune complexes in mercury-treated mice.

The amount of circulating immune complexes (CIC) was determined in mercury-treated Balb/c, SJL and C57BL/6J mice using the conglutinin-binding assay and the modified polyethylene glycol (PEG) precipitation test. SJL mice given mercuric chloride developed a transient increase of CIC by both methods, but the increase was modest compared with aged MRL-lpr/lpr (MRL) mice. Mercury-treated Balb/c mice showed increased levels of CIC by the PEG precipitation test. Blood clearance of intravenously injected preformed soluble IC was not impaired. The mesangial IC-deposits in mercury-treated SJL mice contained significantly more IgG1, but significantly less IgG2a and C3 than the combined mesangial-capillary loop deposits in MRL mice. The MRL mice had a severe proliferative glomerulonephritis, whereas, only a mild mesangial glomerulopathy was seen in the mercury-treated SJL mice. The SJL mice given mercuric chloride showed systemic, granular deposits within the vessel walls of IgG1 but not of C3; a few mice had IgG2 deposits which were accompanied by C3. No histological damage was seen in the vessel walls. The CIC found in mercury-treated SJL and Balb/c mice may be the source of origin of the systemic IC-deposits. One explanation for the mild degree of tissue injury might be that the predominant isotype in the deposits was IgG1, which led to deposition of only small amounts of complement.

Animals↗

PubMed1989

Anti-fibrillarin autoantibodies in mercury-treated mice.

Using indirect immunofluorescence (IF) with HEp-2 cells as a substrate serially bled SJL mice were found to gradually develop a high titre of anti-nucleolar antibodies (ANuA) after 3-5 weeks of s.c. injections of 1.6 mg HgCl2/kg body weight every third day. The ANuA showed a clumpy nucleolar pattern of localization and were composed of all IgG subclasses, but contained, in comparison with the antinuclear antibodies (ANA) in MRL-lpr/lpr mice, significantly lower titres of IgG2a and only traces of IgG3. Immunoblotting analysis using purified mouse liver nucleoli revealed that the sera with ANuA identified the same 34-kD nucleolar protein which was targeted by a human scleroderma serum containing autoantibodies monospecific for fibrillarin. In addition, a fraction of the mercury-treated SJL mice developed serum antibodies reacting with 10-15 and 60-70 kD nucleolar proteins in immunoblotting. The presence of serum autoantibodies reacting with the 10-15 kD proteins correlated with significantly increased titres of anti-histone antibodies of the IgG class in ELISA. Some mercury-treated SJL mice also developed a significantly increased titre of anti-histone antibodies of the IgM class. B10.S mice treated with mercuric chloride consistently developed ANuA, which also targeted a 34-kD nucleolar protein. Since anti-fibrillarin antibodies are specific markers of scleroderma, the present animal model may be valuable for studies of the immunological aberrations which are likely to induce this autoimmune response.

Animals↗

PubMed1989

Mercury induced B-cell activation and antinuclear antibodies in mice.

The effects of mercury exposure on the immune system was investigated in SJL and C57BL/6J mice. 1.6 mg HgCl2/kg body weight was injected subcutaneously every third day for two or four weeks. SJL mice developed splenic cell hyperplasia, with a transiently increased number of splenic cells secreting immunoglobulins of the IgM, IgG and IgG1 isotypes and anti-TNP antibodies, increased serum immunoglobulin concentrations, and antinuclear antibodies with a homogeneous and/or nucleolar pattern. The C57BL/6J mice showed a more short-lived increase in the number of immunoglobulin-secreting splenic cells and serum immunoglobulins, and a weak, exclusively homogeneous ANA pattern consisting of IgM antibodies.

Administration, Cutaneous↗

PubMed1988

Radiation-induced decreases of serous cell immunoglobulin excretions in the rat submandibular gland.

The effect of radiation on the submandibular glands of the rat was studied with special reference to the immune reactivity of IgG and IgA. These immunoglobulins are localized in the serous cells and were influenced by irradiation. Radiation therapy markedly reduced the reactivity for both IgG and IgA. Immunocytochemistry showed a good correlation to the deteriorated morphology as revealed by light and electron microscopy. The local excretion of immunoglobulins in the submandibular gland can thus be affected by radiation and results in an increased risk for oral infections. Pretreatment of animals with the secretagogue cyclocytidine caused less pronounced damage in cellular ultrastructure and immunological findings, as observed by fluorescence microscopy.

Ancitabine↗

PubMed1988

Cellular DNA pattern, S-phase frequency and survival in papillary thyroid cancer.

A series of 150 patients with papillary thyroid cancer diagnosed in Iceland during the 30-year period from 1955 through 1984 was retrospectively analyzed. Flow cytometric analysis of archival paraffin-embedded material was used to study the prognostic significance of cellular DNA content and s-phase frequency. DNA-aneuploidy was found in 12% of the tumors. It was significantly more common in the elderly, in moderately and poorly differentiated carcinomas, in males and in tumors with a high proportion of s-phase cells. Multivariate analysis using stepwise Cox's model showed aneuploidy, age at diagnosis, lymph node metastasis and tumor extension beyond the thyroid capsule as independent prognostic factors. The frequency of cells in s-phase was generally low (mean 2.7%). Patients with high s-phase frequency (greater than 2.5%) had less favorable prognosis than patients with low values (less than or equal to 2.5%).

Adult↗

PubMed1988

Mercury induced antinuclear antibodies in mice: characterization and correlation with renal immune complex deposits.

Female SJL and Balb/c mice were given subcutaneous injections of 1.6 mg HgCl2/kg body weight every third day for 2, 4, 8, or 12 weeks. Indirect immunofluorescence using HEp-2 cells as substrate showed that SJL mice developed antinuclear antibodies (ANA) with a predominantly nucleolar and a weaker, homogeneous nuclear pattern after 4 weeks treatment. The nucleolar antigen was sensitive to treatment with trypsin and RNAse, but the antibody was not absorbed by calf liver RNA. The antigen responsible for the homogeneous nuclear pattern was sensitive to treatment with trypsin, DNAse, and acid solution, but reconstitution with histones on acid treated substrate did not restore the fluorescence. The corresponding antibody was not absorbed by double-stranded or single-stranded DNA, and the Crithidia luciliae assay was negative. This suggests that the antigen responsible for the homogeneous ANA pattern is a non-histone chromatin protein. No autoantibodies were found in Balb/c mice. Electron dense immune deposits containing IgG and C3 in a mesangial-vascular pattern developed after 4 weeks mercury treatment in SJL and Balb/c mice. Acid eluate from kidneys of SJL mice with immune deposits contained tissue-bound ANA with a strictly anti-nucleolar pattern, showing that such antibodies make up part of the renal immune deposits. No autoantibodies were found in the eluate from Balb/c mice. The findings demonstrate that mercury induces a polyclonal autoantibody response in SJL mice, and suggests a restricted antibody response with unknown specificity in Balb/c mice, in both cases leading to immune complex deposits in the kidneys.

Animals↗