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Biomedical subjects

M Andersson

Publications and source records attributed to M Andersson.

At least 307 records · Page 17Linked to original sources
PubMed1993

Synthesis of oligosaccharides with oligoethylene glycol spacers and their conversion into glycoconjugates using N,N,N',N'-tetramethyl(succinimido)uronium tetrafluoroborate as coupling reagent.

Glycosides of glucose and lactose with di- and tetraethylene glycols, transformed into bifunctional (alcohol, ester) spacer molecules, have been synthesized. After deprotection, these spacer glycosides, containing a free carboxyl group, have been transformed efficiently into glycoconjugates using N,N,N',N'-tetramethyl(succinimido)uronium tetrafluoroborate (TSTU) for the formation of an active ester.

Ethylene Glycols↗
PubMed1993

Viral infections trigger multiple sclerosis relapses: a prospective seroepidemiological study.

A neurological surveillance was combined with prospective recording of upper respiratory and gastrointestinal infections and serological diagnosis of five common viral infections in 60 benign multiple sclerosis patients, with a mean follow-up of 31 months. During 4-week at risk (AR) periods encompassing common infections, a significant excess of MS relapses was found in the AR period, with a relative risk of 1.3. A seasonal variation of the MS relapse rate was found with a minimum in summer. There was a significant correlation between the number of AR relapses and the number of common infections per month explaining the periannual distribution of relapses. The non-AR relapses showed no seasonal variation. There was a significant correlation between adenovirus CF titre rises associated with upper respiratory infections and the occurrence of a major MS relapse in the AR period (n = 7), while influenza infections were not followed by a major MS relapse (n = 6). Linear homologies have been demonstrated between adenovirus and basic myelin protein. The epidemiological approach is essential to our understanding of systemic antigens triggering multiple sclerosis activity.

Adult↗
PubMed1993

Pattern of mortality among Danish thorotrast patients.

The mortality pattern among 999 Danish patients who had been subjected to angiography of the carotid artery with the alpha-ray emitting X-ray contrast media Thorotrast during the period 1935-47 was assessed by record linkage with the National Death Registry through 1989. Standardized mortality ratios (SMR) were calculated relative to the general population. The overall SMR was increased by 18 times during the first 3 years after Thorotrast injection. This rate reflects the often serious, underlying neurological conditions for which angiography was performed, however, mortality was increased by 3-4 fold even for the follow up period after the first 3 years. The increase in mortality was evident for all categories of cause of death, the SMR being 11.1 (95% confidence interval (CI) 7.1-16.4) for cirrhosis of the liver, 4.7 (4.1-5.3) for cancer, 1.6 (1.3-1.9) for cardiac disease, 3.3 (2.6-4.2) for cerebrovascular diseases, 3.9 (3.3-4.5) for other natural causes, and 4.4 (3.4-5.6) for violent causes (including suicides). The SMR was generally related positively to young age at injection, to time since injection, and to the amount injected. The excess mortality can be explained only partially by underlying neurological conditions and by diseases known to be induced by Thorotrast (cirrhosis and cancer of the liver, leukaemia and other haematological diseases), and it is suggested that unspecific effects induced by the alpha-radiation of Thorotrast may have contributed.

Cause of Death↗
PubMed1993

Dry powder inhalation of budesonide in allergic rhinitis.

Topical steroids are known to be effective in allergic inflammatory airway diseases. However, progress in the treatment of these diseases has also called for the use of unadulterated drugs, without lubricants and preservatives. Rhinocort Turbuhaler, a multi-dose inhaler containing budesonide as a pure powder, is a newly developed device without any carrier gas, preservatives or lubricants. The efficacy and tolerance of this product were evaluated in 60 patients with birch pollen rhinitis. After a run-in period of 1 week the patients received once daily for 4 weeks either budesonide pure powder (400 micrograms) or placebo in a double-blind randomized fashion. Assessment of efficacy was made by comparing scores for different nasal and eye symptoms. The additional use of antihistamine tablets was assessed. In 22 of the patients nasal peak inspiratory flow rate was measured before and after 1 week of treatment. Budesonide was significantly more effective than placebo in controlling the nasal symptoms (P-values ranging from 0.011-0.045). The use of antihistamine tablets was significantly lower in the budesonide group (P = 0.012). The nasal inspiratory flow rate was increased after 1 week of treatment in the budesonide treated group of patients as compared with placebo (P = 0.007). No differences were observed between the groups with regard to eye symptoms or adverse effects. The results show that budesonide delivered from a dry powder inhaler is an effective and well tolerated treatment of seasonal allergic rhinitis.

Administration, Inhalation↗
PubMed1993

Association of pepsin with type II collagen (CII) breaks control of CII autoimmunity and triggers development of arthritis in rats.

Lewis rats develop arthritis after immunization with heterologous but not homologous rat type II collagen (CII). We have observed that if the rat CII is prepared by pepsin digestion without subsequent extensive purification, it is arthritogenic in Lewis rats. To address whether pepsin in the CII preparations contributed to the development of arthritis and whether this was associated with the induction of an immune response to CII, Lewis rats were immunized with rat CII of various degrees of purity and with various pepsin contents. After immunization with a crude preparation of CII, containing relatively large amounts of pepsin, Lewis rats developed arthritis with an incidence of 80% together with a strong anti-CII autoantibody production. Further purification of the CII on DEAE-Sepharose, which removes pepsin, eliminated the arthritogenic properties and the capacity to activate CII-specific B cells. Likewise, lathyritic CII, prepared without pepsin, induced neither a CII-specific immune response nor arthritis. If, however, pepsin was added to non-arthritogenic batches of rat CII, arthritis appeared at an incidence of 40%. By using an ELISPOT technique to detect antigen-specific interferon-gamma-producing T cells and antibody-producing B cells, the immune response to CII and pepsin can be evaluated. Eleven days after immunization with lathyritic CII and pepsin, a B-cell response towards both CII and pepsin was seen. Pepsin-specific T cells were also seen at day 11, but CII-specific T cells did not appear until day 14 after immunization. In addition, a weak CII-specific proliferative response of the T cells could be demonstrated at day 14 but not at day 11 or 12. These data show that pepsin plays an important role in the triggering of a CII-specific immune response. We suggest a carrier-hapten mechanism where pepsin acts as a carrier and CII as a 'hapten' which will activate CII-specific B cells. Subsequently these CII-specific B cells will break the T-cell tolerance and evoke a T-cell-mediated immune response towards CII.

Animals↗
PubMed1993

Plasma exudation and solute absorption across the airway mucosa.

The airway mucosa responds to inflammatory provocations with bulk exudation of plasma into the airway tissue (vascular exudation) and lumen (mucosal exudation). The intensity and time course of the exudative response can be relevantly examined by sampling and analysing airway surface liquids, because the luminal entry of plasma proteins/tracers promptly and quantitatively reflects the exudative response of the airways. The process of mucosal exudation of plasma is a prominent feature of airway inflammation and has been demonstrated in rhinitis, asthma, and bronchitis. Inflammatory mediators and allergen produce mucosal exudation of plasma into the airway lumen (outward permeability) whereas the solute absorption across the mucosa (inward permeability) is unaffected. Hence, in contrast to current views, we have demonstrated that in airway inflammation the solute absorption across the airway mucosa is not increased. The findings suggest the plasma exudation response also as a first line respiratory mucosal defence, allowing potent plasma protein systems to appear on an airway mucosa functionally intact as a barrier toward undue luminal material. Our data on plasma exudation and solute absorption across the mucosa of upper and lower airways further suggest the human nasal airways as a model relevant also for the tracheobronchial airways.

Animals↗
PubMed1993

Reversion of autocrine transformation by a dominant negative platelet-derived growth factor mutant.

A non-receptor-binding mutant of the platelet-derived growth factor (PDGF) A chain, PDGF-0, was generated by exchanging 7 amino acids in the sequence. The mutant chains formed dimers that were similar to wild-type PDGF-AA with regard to stability and rate of processing to the mature 30-kDa secreted forms. Moreover, the mutant chains formed disulfide-bonded heterodimers with the PDGF B chain in NIH 3T3 cells heterodimer underwent the same processing and secretion as PDGF-AB. Transfection of c-sis-expressing 3T3 cells with PDGF-0 significantly inhibited the transformed phenotype of these cells, as determined by the following criteria. (i) Compared with PDGF-0-negative clones, PDGF-0-producing clones showed a reverted morphology. (ii) Clones producing PDGF-0 grew more slowly than PDGF-0-negative clones, with a fivefold difference in cell number after 14 days in culture. (iii) The expression of PDGF-0 completely inhibited the ability of the c-sis-expressing 3T3 cells to form colonies in soft agar; this inhibition was overcome by the addition of recombinant PDGF-BB to the culture medium, showing that the lack of colony formation of these cells was not due to a general unresponsiveness to PDGF. The specific expression of a PDGF-0/PDGF wild-type heterodimer in COS cells revealed that the affinity of the mutant heterodimer for the PDGF alpha receptor was decreased by approximately 50-fold compared with that of PDGF-AA. Thus, we show that a non-receptor-binding PDGF A-chain mutant neutralizes in a trans-dominant manner the autocrine transforming potential of the c-sis/PDGF B chain by forming low-affinity heterodimers with wild-type PDGF chains. This method of specifically antagonizing the effect of PDGF may be useful in investigations of the role of PDGF in normal and pathological conditions.

3T3 Cells↗
PubMed1993

Effect of seasonal allergic rhinitis on airway mucosal absorption of chromium-51 labelled EDTA.

BACKGROUND: Hyperpermeability of the airway mucosa is thought to be characteristic of allergic rhinitis and asthma. Nine subjects with seasonal rhinitis caused by birch pollen were studied and the nasal mucosal absorption of chromium-51 labelled EDTA was examined both in an asymptomatic period before the season and late into the season when significant allergic rhinitis symptoms were present. METHODS: A nasal pool device was used to keep a concentration of the absorption tracer in contact with a larger part of the mucosa of the ipsilateral nasal cavity. Absorption was allowed for 15 minutes and measured as the radioactivity appearing in the 24 hour urine sample. RESULTS: The nasal absorption of 51Cr-EDTA in subjects with seasonal allergic rhinitis was less during active disease than before the season. CONCLUSIONS: An airway epithelial barrier that is subject to prolonged eosinophilic inflammation may not be disrupted but may rather increase its functional tightness.

Absorption↗
PubMed1993

Effects of nicotine on the human nasal mucosa.

BACKGROUND: Topical application of nicotine and stimulation of tachykinin containing sensory nerves have been shown to produce mucosal exudation of plasma and derangement of the epithelial lining in guinea pig and rat airways. If this occurred in man these effects might contribute to the pathogenesis of airway disease. This study, performed in healthy volunteers without atopy, examined whether nicotine affects the plasma exudation response and the mucosal absorption permeability of the human nasal airway. METHODS: The acute effects of increasing topical doses of nicotine (0.08-2.0 mg) were examined (n = 8) on nasal symptoms (pain), mucosal exudation of plasma (albumin), mucosal secretion of mucin (fucose), and mucosal exudative responsiveness (histamine induced mucosal exudation of albumin). A separate placebo controlled study was carried out to determine whether frequent applications of the high dose of nicotine (2.0 mg given eight times daily for nine days) had any deleterious effects on the airway mucosa detectable as altered responses to histamine challenge. Both mucosal exudation of plasma (n = 12) and mucosal absorption of chromium-51 labelled EDTA (n = 8) were thus examined in nasal airways exposed to both nicotine and histamine. RESULTS: Nicotine caused nasal pain and produced dose dependent mucosal secretion of fucose but failed to produce any mucosal exudation of albumin. The exudative responsiveness to histamine was, indeed, decreased when the challenge was performed immediately after administration of acute doses of nicotine, whereas the responsiveness was unaffected when histamine challenges were carried out during prolonged treatment with nicotine. The nasal mucosal absorption of 51Cr-EDTA in the presence of histamine did not differ between subjects receiving either placebo or nicotine treatment for nine days. CONCLUSIONS: The results indicate that nicotine applied to the human airway mucosa produces pain and secretion of mucin, but inflammatory changes such as mucosal exudation of plasma and epithelial disruption may not be produced. Neurogenic inflammatory responses, which are so readily produced in guinea pig and rat airways, may not occur in human airways.

Absorption↗
PubMed1993

Synaptonemal complex analysis of a reciprocal translocation, rcp(20;24) (q17;q25), in a subfertile bull.

A reciprocal translocation was identified in a subfertile artificial insemination bull. Somatic chromosome investigation of G-banded metaphases demonstrated a 60,XY,rcp(20;24)(q17;q25) karyotype for the carrier. Synaptonemal complex analysis of the translocation by electron microscopy revealed an irregular pairing behavior of the chromosome axes involved, which resulted in a variety of configurations at pachytene. Not only was the expected quadrivalent configuration present, but also a trivalent plus univalent and two heteromorphic bivalents. Most common was an incompletely or completely paired quadrivalent configuration, which was non-homologously paired. XY association with the multivalent was seen only rarely. Histological analysis of testicular tissue showed meiotic arrest in some tubules. However, the semen picture was normal.

Animals↗
PubMed1993

Influence of triacylglycerol biosynthesis rate on the assembly of apoB-100-containing lipoproteins in Hep G2 cells.

Apolipoprotein B-100 (apoB-100) appears in three forms in the endoplasmic reticulum of Hep G2 cells: (1) tightly bound to the membrane, ie, not extractable by sodium carbonate. This form is glycosylated but protease sensitive when present in intact microsomes, suggesting that it is only partially translocated to the microsomal lumen; (2) extractable by sodium carbonate and present on low-density lipoprotein-very-low-density lipoprotein (LDL-VLDL)-like particles. This form is glycosylated and secreted into the medium; and (3) extractable by sodium carbonate but having a higher density than the LDL-VLDL-like particles. This form, referred to as Fraction I, is glycosylated and protected against proteases when present in intact microsomal vesicles, indicating that it is completely translocated to the luminal side of the microsomal membrane. Fraction I is not secreted into the medium, but it disappears with time from the cell, suggesting that it is degraded. Oleic acid induced a 2.7-fold increase in the rate of the biosynthesis of triacylglycerol but not of phosphatidylcholine in Hep G2 cells. Incubation of the cells with oleic acid had no significant effect on the rate of initiation of the apoB-100-containing lipoproteins, nor did it influence the amount of apoB-100 that was associated with the membrane or the turnover of apoB-100 in the membrane. Instead, it increased the proportion of the nascent apoB polypeptides on initiated lipoproteins that was converted into full-length apoB-100 on LDL-VLDL-like particles, giving rise to an increased amount of these particles in the lumen of the secretory pathway. Pulse-chase experiments showed that incubation with oleic acid gave rise to an increased formation of LDL-VLDL-like particles on behalf of the formation of Fraction I. This effect of oleic acid could partially explain the protective effect of the fatty acid on apoB-100, preventing it from undergoing posttranslational degradation.

Apolipoprotein B-100↗
PubMed1993

A new all-ceramic crown. A dense-sintered, high-purity alumina coping with porcelain.

A method of manufacturing an all-ceramic crown composed of a coping of dense-sintered, high-purity alumina with dental porcelain is described. This method takes the sintering shrinkage of alumina into consideration and makes it possible to produce individual dental copings in dense-sintered, high-purity alumina, which is a biocompatible implant material. The alumina used has density, grain size, and flexural strength within the limits of the values required in ISO 6474-1981, 'Implants for surgery, ceramic materials based on alumina'.

Acid Etching, Dental↗
PubMed1993

Mucosal exudation of fibrinogen in coronavirus-induced common colds.

We studied the mucosal exudation of plasma in relation to pathophysiological events during an induced common cold. Coronavirus 229E was inoculated nasally in 20 healthy volunteers under controlled conditions. Ten volunteers developed the common cold, determined by symptom scores and serology. The bulk plasma exudate was monitored, using fibrinogen (MW 340 kD) in nasal lavage fluids as an endogenous marker. Following inoculation, anterior rhinoscopy and objective registrations of nasal mucosal temperature, nasal discharge weight, and nasal blockage index by peak expiratory air flow, were followed twice daily for 6 days. Mucosal plasma exudation, as assessed by fibrinogen in lavage fluids, increased hundredfold after virus inoculation, concomitantly with the subjective symptoms and objective physiological changes. We propose that this exudation reflects the degree of subepithelial inflammation, and suggests that plasma bulk exudate, including all potent plasma protein systems may be involved in the resolution of acute viral rhinitis--common cold.

Adult↗
PubMed1993

Therapy-related myelodysplasia and acute myeloid leukemia. Cytogenetic characteristics of 115 consecutive cases and risk in seven cohorts of patients treated intensively for malignant diseases in the Copenhagen series.

Therapy-related acute myeloid leukemia (t-AML), often presenting as myelodysplasia (t-MDS), has become the most serious long-term complication of cancer therapy and offers a unique opportunity to study chemical leukemogenesis. Seven cohorts of patients treated for six different types of primary tumor have been followed closely for leukemic complications, and 115 consecutive patients with t-MDS or t-AML, including 45 cases from the cohorts, have been investigated cytogenetically at our institutions during the past 16 years. In patients primarily treated with alkylating agents, the risk of t-MDS and t-AML increased by approximately 1% per year from 2 to at least 8 years after start of treatment. In most cases, the disease presented as t-MDS with loss of a whole chromosome 5 or 7, or various parts of their long arms, and the leukemias were of FAB-subtypes M1, M2, or M4. In patients treated with drugs targeting at DNA-topoisomerase II, such as etoposide, doxorubicin, 4-epidoxorubicin, or mitoxantrone combined with drugs reacting directly with DNA, such as cisplatin or alkylating agents, the risk of leukemia increased much more steeply from only one year after start of therapy. These early onset cases often presented as overt leukemia of FAB-subtypes M4 or M5 with balanced translocations to chromosome bands 11q23 and 21q22, whereas later onset cases often shared characteristics with cases observed after therapy with alkylating agents alone. Both alkylation of DNA and poisoning of DNA-topoisomerase II may result in development of t-AML with different clinical and cytogenetic characteristics. There may be a synergistic leukemogenic effect between the two types of drug, and in patients with germ cell tumors treated with etoposide, cisplatin and bleomycin, reassessment suggested the risk of leukemia to increase exponentially with increasing doses of cisplatin and etoposide.

Adult↗
PubMed1993

Leukemia and other related hematological disorders among Danish patients exposed to Thorotrast.

At least 60 case studies of leukemia among people exposed to chronic low-dose alpha-particle radiation from injections with the radiographic contrast medium Thorotrast and 115 cases from follow-up studies have been described in the literature. In the present study, malignant hematological diseases among 1003 Danish patients injected during 1935-1947 and followed to 1992 accruing 20,433 person-years were assessed and available histopathological specimens revised. The mean cumulative bone marrow alpha-particle radiation dose (1.34 Gy) was estimated from records of the amount of Thorotrast injected (mean 18.7 ml). Sixteen cases of acute myelogenous leukemia (AML) and seven cases of myelodysplastic syndrome (MDS) were diagnosed 8-40 years after injection, the cumulative frequency reaching 7.6%. No significant relationship was seen between the cumulative frequency of AML + MDS and the age at injection, gender, or amount of Thorotrast injected, but a multivariate analysis described data best by a model with the bone marrow dose and the power of the attained age. The risk estimate for AML + MDS was 173 cases/10(4) persons per Gy. If also considering cases of acute lymphocytic leukemia (1), chronic myelogenous leukemia (3), non-Hodgkins lymphoma (4), and multiple myeloma (2), the risk estimate became 248 cases/10(4) persons per Gy. It is suggested that RBE of alpha particles from thorium may be lower than 20.

Adolescent↗
PubMed1993

Anti-Purkinje cells antibodies in two cases of paraneoplastic cerebellar degeneration.

The serum and CSF of two women with a severe subacute pancerebellar syndrome contained high titers of antibodies directed against antigens present in the perikaryon of Purkinje cells. In Western blots performed on human Purkinje cells extracts these antibodies reacted with two groups of proteins the molecular weights of which were estimated to 34-38 and 62 kilodaltons (anti-Yo antibodies). Complementary investigations revealed a tubar adenocarcinoma in the first case, an ovarian carcinoma in the second. The tubar tumoral cells also contained the protein of the highest molecular weight. Compared to the serum, the CSF contained a higher proportion of anti-Yo antibodies per mg IgG, and a fraction of the latter was likely synthesized intrathecally. These antibodies may be involved in the almost total disappearance of the Purkinje cells, as observed at autopsy of both cases.

Adenocarcinoma, Papillary↗
PubMed1993

Survival of Danish cancer patients 1943-1987. Buccal cavity and pharynx.

Cancers of the buccal cavity and pharynx are anatomically related and (with the exception of cancers of the salivary glands and nasopharynx) share risk factors, i.e., tobacco and alcohol. For cancers of the lip ("lipstick area") exposure to sunlight is also an important risk factor. Cancers of the buccal cavity and pharynx are rare tumours, accounting for less than 2% of all malignant tumours in Denmark. The largest group is lip cancers (6545 cases in 1943-87) for which the survival rate remained high during the study period, 95-99% of patients surviving longer than five years. Survival from cancer of the tongue (1555 cases in 1943-87) and cancer of the mouth (2770 cases) also remained fairly constant during the period; the relative one-year survival rate for males were 57% for tongue cancer and 75% for mouth cancer in 1983-87. Survival (Kaplan-Meier estimates) from cancers at either site diagnosed in 1978-87 was better for females than for males; however, relative mortality was higher among males than among females for cancer of the tongue (16.3 after one year compared to 11.9 among females), while relative mortality for mouth cancer was 8.9 and 7.8, respectively. After five years, relative mortality was 1.6 and 2.6 for male patients and 1.7 and 1.6 for female patients with cancer of the tongue and mouth. Five-year survival rate after cancer of the salivary glands (2147 cases) fell from 73 in males and 81% in females in 1943-47 to 45 and 71% in 1983-87. During the same period, however, the incidence rate almost halved, and patients were generally older at presentation, with more advanced tumours. The one-year survival rate from tumours of the pharynx (2948 cases; 38% in the tonsils, 28% in the naso-pharynx and 25% in the hypopharynx) increased between 1943 and 1987 from 48% in males and 48% in females to 59% and 67%. After five years, relative mortality was still high in both males (2.5), and females, (4.9).

Age Factors↗