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Biomedical subjects

L Hammarström

Publications and source records attributed to L Hammarström.

At least 325 records · Page 18Linked to original sources
PubMed1983

An enzyme histochemical study of human salivary duct calculi.

An investigation was undertaken to study the distribution of enzymes associated with submandibular gland salivary calculi. Ten calculi were freeze-sectioned and incubated for acid and alkaline phosphatases and for lactate, succinate and maleate dehydrogenases. All calculi were partly covered by a 50-210 micrometers wide zone of organic material consisting of connective tissue and metaplastic squamous epithelium facing the mineralized calculus, or of a structureless substance attached to the mineralized calculus. The epithelium showed an intense staining reaction for acid phosphatase and lactate dehydrogenase and a moderate reaction for succinate dehydrogenase throughout all levels of the epithelium. The structureless peripheral zone exhibited a moderate activity of acid phosphatase and succinate dehydrogenase located to an area close to the mineralized matrix. Also alkaline phosphatase and lactate dehydrogenase were found in a special pattern in the structureless zone. Sodium fluoride and sodium vanadate added to the incubation medium inhibited acid phosphatase activity whereas cupric chloride only lowered the staining reaction. Enzyme activity was found only within the peripheral zone of organic material with one exception. The results suggest that the calcification process of salivary calculi is not a passive calcification of necrotic material or mucin but rather an active process promoted by enzymes in the surrounding organic substances.

Acid Phosphatase↗
PubMed1983

Mitoses and microorganisms in the periodontal membrane after storage in milk or saliva.

Milk and saliva were tested in vitro as potential storage media for avulsed teeth. Developing monkey teeth were extracted and stored in milk or saliva for periods ranging from 1 to 6 h. The osmolality, pH, conductivity and number of viable bacteria in the media were determined after predetermined intervals during the storage periods. After the storage periods the teeth were either prepared for scanning electron microscopy or cultured for 24 h in Eagle's medium supplemented with 3H-thymidine. In the scanning electron microscope numerous adherent bacteria were seen covering the periodontal membrane after storage in saliva but none were found after storage in milk. The cultured teeth were sectioned and evaluated with autoradiography. Superficial parts of the periodontal membrane were rapidly injured by storage in saliva while the epithelial root sheath and the apical pulpal cells were affected at a later stage. Cells neighboring the cementoblasts incorporated 3H-thymidine after 6 h storage in milk but not after storage in saliva for the same length of time. It was concluded that the low osmolality in combination with bacteria which adhered to the periodontal membrane made saliva less suited than milk for long time storage of avulsed teeth. Furthermore, a viable layer of cells close to the root surface seemed to be a prerequisite for a successful healing without root resorption after replantation.

Animals↗
PubMed1983

Gm allotypes in Swedish myasthenia gravis patients.

Gm phenotype frequencies were examined in 112 Swedish myasthenia gravis patients. The G1m 1,2,3 phenotype frequency in the total patient material did not differ significantly from that found in the normal population. However, when patients were subdivided, three different patient groups were observed with regard to Gm1 frequency: (1) Thymoma patients having a low frequency of Gm1, (2) Non-thymoma patients with a mild disease having a low frequency of Gm1 and (3) Non-thymoma patients with a severe disease having a high frequency of Gm1. When patients were subdivided according to presence or absence of HLA-B8 and Gm1 respectively, severe symptoms were less frequent in the HLA-B8+, Gm(-1) group as compared to the HLA-B8+, Gm(+1) group. Furthermore, there was an increased frequency of sera with anti-immunoglobulins not inhibitable by pooled control immunoglobulins.

Antibodies, Anti-Idiotypic↗
PubMed1983

Virus-specific antibody activity of different subclasses of immunoglobulins G and A in cytomegalovirus infections.

Healthy donors and patients with primary or reactivated cytomegalovirus infections were examined for antiviral antibodies of the immunoglobulin G (IgG) and IgA subclasses. For this purpose, monoclonal antibodies against the four IgG and the two IgA subclasses were used in enzyme-linked immunosorbent assays with cytomegalovirus antigen. IgG1 and IgG3 were the principal anti-cytomegalovirus subclasses in serum samples from healthy donors and patients. IgG1 was higher in reactivated than in primary disease. Cytomegalovirus-specific IgG2 was detected only in serum samples with high total cytomegalovirus IgG. A few patients with high total serum IgG4 also had cytomegalovirus-specific IgG4 antibodies. During convalescence, there was no significant increase in total IgG of any subclass. Both IgA1 and IgA2 antibodies with cytomegalovirus specificity were detected in patients who had cytomegalovirus antibodies of the IgA class.

Antibodies, Viral↗
PubMed1983

Role of penicillamine for the induction of myasthenia gravis.

Penicillamine and derivatives of this drug were tested for lymphocyte-activating properties. D- as well as L-penicillamine induced in vitro DNA synthesis in mouse splenocytes, whereas D-penicillamine methyl ester, N-acetyl-D-penicillamine and D-penicillamine disulfide were devoid of stimulatory properties. Lymphocytes from athymic mice were also responsive. However, we were unable to detect an increased antibody secretion in mouse spleen cell cultures exposed to penicillamine. Human peripheral blood lymphocytes from healthy individuals as well as from patients with penicillamine-induced myasthenia gravis only gave minor proliferative responses after in vitro penicillamine exposure. Furthermore, there were no differences in proliferative capacity between these two groups. Cultivated human peripheral blood or spleen cells were not activated to antibody secretion in the presence of penicillamine. There were no signs of myasthenia gravis using single-fiber electromyography recordings in patients with rheumatoid arthritis being on penicillamine treatment or in mice from several different mouse strains receiving penicillamine in their drinking water. However, NZB/NZW hybrid mice receiving penicillamine had increased amounts of antinuclear and anti-dsDNA antibodies.

Animals↗
PubMed1983

Storage of experimentally avulsed teeth in milk prior to replantation.

Extracted monkey teeth were endodontically treated, stored in milk or saliva for two or six h, and then replanted. Periodontal conditions were evaluated after eight wk. Teeth that had been stored for two or six h in milk or for two h in saliva showed periodontal healing almost as good as that of immediately replanted teeth. Teeth that had been kept in saliva for six h or bench-dried for one h showed extensive replacement resorption. Milk may thus be recommended as a storage medium for ex-articulated teeth prior to replantation in cases when immediate replantation is not possible.

Animals↗
PubMed1983

Periodontal healing of replanted monkey teeth prevented from drying.

Root resorption of replanted teeth is dependent on the duration of the extra-alveolar period and on the storage environment. In the present investigation the significance of preserving the humidity of the periodontal ligament (PDL) during the extra-alveolar period was tested on isolated PDL cells and on replanted monkey teeth. The isolated PDL cells were tested with respect to cell viability (trypan blue exclusion test) and to cell recovery (number of cells after additional cultivation). About 70% of the cells were viable and 44% recovered after 1 h in a humid atmosphere. Practically no cells were viable or recovered after 1 h of drying. Replanted teeth that had been wrapped in plastic foil for 1 h before replantation showed no more resorption than immediately replanted teeth. This is in contrast to teeth dried in air for 1 h before replantation. They showed extensive root resorption on almost all root surfaces. Thus, prevention of evaporation of tissue fluid from the PDL must be considered a primary goal if the tooth cannot be replanted immediately.

Animals↗
PubMed1983

IgG2 deficiency in a healthy blood donor. Concomitant lack of IgG2, IgA and IgE immunoglobulins and specific anti-carbohydrate antibodies.

Lack of serum IgG2, IgA and IgE was found in a healthy male adult blood donor. No secretory IgA could be demonstrated. In vitro activation of lymphocytes did not induce IgA secreting cells although no class specific suppressor cells could be found. Normal or slightly subnormal titres to a variety of bacterial and viral antigens were demonstrated whereas anti-carbohydrate antibodies (anti-teichoic acid, anti-dextran and anti-pneumococcal polysaccharide) were virtually absent. Isoagglutinins and heteroagglutinins were present in somewhat lower concentrations than normal.

Adult↗
PubMed1983

Functional maturity of cord blood B lymphocytes: Staphylococcus aureus Cowan 1 induces IgG secretion in the human neonate.

Lymphocytes from newborn infants and adults were investigated with the polyclonal B cell activators Staphylococcus aureus Cowan 1, soluble protein A, and pokeweed mitogen (PWM). In cord blood lymphocytes (CBL), protein A and PWM induced only meagre IgM responses, whereas Cowan 1 bacteria induced synthesis of both IgM and IgG in quantities comparable to adult levels. We were also able to establish the neonatal origin of the Ig producing cells. Thus, cord blood lymphocytes seem to be functionally mature enough to produce any Ig class, provided they are given the right stimulus.

Adult↗
PubMed1983

Human leukocyte antigens group A in couples with unexplained infertility.

The human leukocyte antigen (HLA) frequencies and antigen sharing were studied in 14 couples with unexplained infertility. There were no significant differences in the frequency of HLA-A, B, C, or DR antigens, as compared with normal control subjects. Furthermore, the degree of HLA sharing did not deviate from that theoretically expected. An increased frequency of HLA-DR sharing, as compared with the expected frequency, was observed in a control group consisting of parents of children with leukemia. When infertile spouses were tested for mixed lymphocyte culture reactivity, there were no indications of an altered reactivity, as compared with control subjects.

Female↗
PubMed1982

Binding and incorporation of lecithin-cholesterol vesicles to lymphocytes: a spin-label study.

When lecithin-cholesterol vesicles, containing the membrane-bound spin probe 3-doxyl-cholestane, were set in contact with mouse lymphocytes, the vesicles adsorbed to the cell and vesicle-membrane components were transferred to it. The spin probe was enzymatically reduced at the inside of the cell membrane. The spin-label method provided a means to determine quantitatively the extent of vesicles adsorption and vesicle-cell fusion by measuring the transfer of vesicles membrane material to the cell. This method, together with the reduction of spin label by the cell, allowed also a quantitative estimate to the extent of endocytosis during cell-liposome interaction.

Animals↗
PubMed1982

Sex-dependent induction of human suppressor T cells by chorionic gonadotropin.

Human chorionic gonadotropin (hCG) in physiological retroplacental concentration has been shown to induce human female lymphocytes which suppress the proliferation and differentiation of B cells stimulated by purified protein derivative of tuberculin. To test whether the hCG-induced suppression was sex dependent parallel experiments using female and male peripheral lymphocytes were performed. hCG did not induce cells capable of suppressing purified protein derivative induced B cell proliferation in lymphocytes from males, which was in contrast to lymphocytes from females where a statistically significant suppression was found. A similar hCG-induced suppressive effect was found before menarche, after the menopause and in two patients with Turner's syndrome, suggesting that a gene(s) on the Y chromosome exerts a regulatory function and thus prevents the hormone from inducing suppressor T cells.

Aging↗
PubMed1982

Evidence for a spontaneous activity and a weak helper function in cord blood lymphocytes.

Human lymphocytes from cord blood (CBL) and adult peripheral blood were studied for suppressive and stimulatory effects. Using a double chamber assay we found that via soluble substance(s) cells from approximately 90% of all cord bloods and about 25% of the tested adults could diminish the proliferative response and the IgM and IgG plaque-forming cell numbers of phytohemagglutinin (PHA) stimulated adult cell cultures. CBL were spontaneously suppressive, whereas cells from 'suppressive adults' required activation with PHA to exert suppression. Co-cultures of T cells and B cells were stimulated with pokeweed mitogen. Cord B lymphocytes were able to secrete not only IgM but also IgG. The Ig response of CBL was weaker than that of adult cells, which argues for an immaturity of cord helper T lymphocytes, and possibly also of cord B lymphocytes.

Female↗
PubMed1982

An enzyme histochemical study of dental plaque and calculus.

The following investigation was undertaken to study the location in the dental plaque and calculus of certain enzyme activities and to compare the patterns obtained with those of the normal hard tissue formation. Supragingival and subgingival calculus attached to the root surfaces of 30 extracted teeth was studied. The root with its deposits was frozen rapidly in a mixture of hexane and solid CO2 (-75 degrees C). From the frozen block, sections were cut and incubated for histochemical demonstration of lactate dehydrogenase, alkaline phosphatase and acid phosphatase. The plaque seemed to be stratified with regard to enzyme activity. Three different layers could be identified. In the basal layer, approximately 100 microns thick, enzyme activity was low. Lactate dehydrogenase activity could be identified in some sections, but no phosphatase activity. In the middle layer lactate dehydrogenase, alkaline phosphatase and acid phosphatase activities were found in most of the sections. The superficial layer usually showed lactate dehydrogenase but not always acid or alkaline phosphatase activities. The results of the present investigation may suggest that the mineralization of the dental plaque is not only a passive mineralization of dead bacteria, but also an active process promoted by enzymes in the covering bacterial layers.

Acid Phosphatase↗
PubMed1982

Lead levels determined in Swedish permanent teeth by particle-induced X-ray emission.

The determination of lead in permanent teeth is a useful measure of past exposure in early childhood since these teeth are mineralized in early childhood. Particle-induced X-ray emission (PIXE) analysis has been shown to be a method with good applicability for the contamination-free analysis of elements heavier than calcium in dental hard tissues. The method is rapid and nondestructive. The purpose of this study, which used the PIXE technique, was to survey the average level of lead in the coronal dentin of permanent bicuspid teeth collected in three places representing Swedish urban and rural areas. In addition teeth from the New York City area were analyzed. The material comprised 165 teeth from Sweden and, for comparison, 14 teeth from New York City. The median value of lead in the Swedish teeth was 2.9 micrograms/g, a value indicating an insignificant influence from the environment in comparison to the New York teeth, for which the median value was 9.2 micrograms/g. There was however a statistically significant difference in the lead concentration of teeth from large and small Swedish cities; this finding may reflect different automobile traffic intensity.

Adolescent↗
PubMed1982

The visualization of the patterns of ameloblast modulation by the glyoxal bis(2-hydroxyanil) staining method.

Several red stripes appeared on the surface of the rat incisor enamel at the maturation stage when stained with a modified glyoxal bis (2-hydroxyanil) method (GBHA). The stripes running across the maturation enamel were correlated directly, morphologically, and indirectly, using 45Ca autoradiography, with the bands of overlying smooth-ended ameloblasts. In addition, GBHA strain revealed similar stripes on the maturation enamel of the developing teeth from a variety of animals (rat molar, bovine incisor and molar, porcine canine, and monkey incisor), indicating that the maturation of the mammalian tooth enamel, in general, is under the control of two types of maturation ameloblasts which undergo cyclic morphologic changes.

Ameloblasts↗