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Biomedical subjects

L Danielsson

Publications and source records attributed to L Danielsson.

At least 37 records · Page 2Linked to original sources

Increasing incidence of childhood coeliac disease in Sweden. Results of a national study.

A survey of the incidence of coeliac disease was carried out by asking all 43 paediatric departments in Sweden to report the number of children born between 1978 and 1987 in whom coeliac disease had been diagnosed. Thirty-four departments representing a population of 7.18 million reported 1944 cases of coeliac disease among 804,935 children born between 1978 and 1987. The cumulative incidence of coeliac disease was 1.7 per 1000 live births in children born between 1978 and 1982 and doubled to 3.5 per 1000 live births in children born after 1982. The highest incidence was found in the southern and south-eastern regions of the country. The observed increase may have been influenced by changes in infant feeding practices such as the postponed age of introduction of gluten from four to six months of age and an increase in gluten content of proprietary baby foods.

Celiac Disease↗

Human monoclonal antibodies with different fine specificity for digoxin derivatives: cloning of heavy and light chain variable region sequences.

Human-mouse hybridoma cell lines producing human monoclonal antibodies against the cardiac glycoside digoxin were established after in vitro immunization or direct immortalization of human peripheral blood lymphocytes with digoxin. Three antibodies, designated MO6, LH92 and LH1114, displayed different patterns of fine specificity against digoxin and several digoxin analogues, as elucidated by inhibition ELISA. All three monoclonal antibodies had mu heavy chains, two of them (MO6 and LH114) had kappa light chains and one (LH92) lambda light chains. DNA encoding the variable regions of both heavy and light chains of the three antibodies were amplified from cDNA using the polymerase chain reaction (PCR). The nucleotide sequences of the amplified DNA were determined after subcloning of PCR fragments in M13 vectors. The deduced amino acid sequences revealed considerable sequence differences in the complementarity determining regions between the three antibodies.

Amino Acid Sequence↗

Is gluten challenge necessary for the diagnosis of coeliac disease in young children?

Sixty-seven children under 2 years of age presenting with a classic clinical picture of coeliac disease with a severe small-intestinal mucosal lesion were investigated. All improved clinically and histologically on a gluten-free diet. During gluten challenge the mucosal damage recurred in 64 (95.5%) children, thus fulfilling the criteria for coeliac disease formulated by the European Society for Paediatric Gastroenterology and Nutrition. Three (4.5%) children had no mucosal relapse 2 years or more after return to a gluten-containing diet. These children were classified as having transient gluten intolerance. The low frequency of non-relapsers in the present study calls into question the practice of performing gluten challenge.

Biopsy↗

Rapid cloning of rearranged immunoglobulin genes from human hybridoma cells using mixed primers and the polymerase chain reaction.

A general method to directly obtain the DNA sequence of the variable regions of any immunoglobulin chain using a mixture of oligomer primers and the polymerase chain reaction (PCR) is described. Mixed oligonucleotide primers corresponding to the 5' signal peptide and a conserved 3' constant region primer were used for enzymatic amplification of each of the heavy and light chain variable regions of a human hybridoma producing a monoclonal antibody recognizing an epitope of gp120 of the human immunodeficiency virus 1. The amplified DNA segments were cloned and the sequence was determined for the heavy chain variable region. This method will greatly facilitate structural and functional studies of immunoglobulins by reducing the effort to clone and sequence the members of the immunoglobulin as well as other multigene families.

Amino Acid Sequence↗

Chronic non-specific diarrhea of infancy successfully treated with trimethoprim-sulfamethoxazole.

Fifteen children who fulfilled the criteria of chronic non-specific diarrhea of infancy were evaluated for intestinal bacterial overgrowth. In 10 of 11 successfully investigated children we found bacterial overgrowth of the small intestine by upper respiratory tract microflora. In 9 of 10 children (group I) treated with trimethoprim-sulfamethoxazole the diarrhea ceased immediately, whereas in all children in group II (n = 5; 3 children excluded because of growth of Yersinia enterocolitica) treated with low-lactose diet the diarrhea persisted (p = 0.004). The results indicate that bacterial overgrowth of the small intestine by upper respiratory tract microflora may be a cause of chronic non-specific diarrhea and that this diarrhea may be successfully treated with trimethoprim-sulfamethoxazole.

Anti-Bacterial Agents↗

Human monoclonal antibodies against a recombinant HIV envelope antigen produced by primary in vitro immunization. Characterization and epitope mapping.

Peripheral blood lymphocytes from healthy, HIV sero-negative blood donors have been in vitro immunized using penv9, a recombinant fragment of the envelope of HIV-1. This primary in vitro immunization followed by Epstein-Barr virus (EBV) transformation and somatic cell fusion subsequently gave rise to several specific anti-penv9 monoclonal antibodies (MO28, MO30 and MO43) of mu isotype. The hybridomas have been kept in culture for over 6 months and the antibody productivity for MO30 was measured to 18 micrograms x (24 hr x 10(6) cells)-1. The fine specificity of the antibodies was mapped by a peptide inhibition enzyme immunoassay, using overlapping synthetic pentadeca peptides covering the whole penv9. These human monoclonal antibodies exhibited a similar epitope specificity directed against a non-sequential determinant, including the amino acids 632-646, 677-681 and 687-691. This specificity is very rarely found in immune sera from seropositive patients and presently not reported in human monoclonal antibodies derived from in vivo immunized individuals, indicating that different antibody specificities can be obtained by the in vitro immunization technology. These human monoclonal antibodies did not neutralize HIV. The results presented here demonstrate the feasability of generating human monoclonal antibodies against HIV by primary in vitro immunizations, thereby avoiding the use of lymphocytes derived from infected patients when human monoclonal antibodies for therapeutic purposes are to be produced.

Antibodies, Monoclonal↗

The effect of leucyl-leucine methyl ester on proliferation and Ig secretion of EBV-transformed human B lymphocytes.

The selective cytotoxicity of the lysosomotropic methyl esters of leucine or its lysosomal condensation product leucyl-leucine has been used to investigate the effect of cytolytic cells on the clonal outgrowth, cellular proliferation and antibody secretion of Epstein-Barr virus (EBV)-transformed human B cells. Large granular lymphocytes (LGL), monocytes, and a subset of T cells (CD8/CD11+) were permanently eliminated by the ester treatment. These lysosome-rich cells severely inhibit the clonal outgrowth of EBV-infected B cells, as determined by Poisson distribution calculations. Furthermore, leucyl-leucine methyl ester-treated and EBV-infected lymphocytes showed a significant increase in proliferative capability as well as immunoglobulin (Ig) production (three to 11 times) compared to non-treated but similarly infected lymphocytes. Since the effect of leucyl-leucine methyl ester treatment was also detectable in low-density (100 B cells/well) cultures, the suppression was unlikely to be exerted by EBV-specific T-cell clones, but pointed rather to the natural killer (NK) cells as effectors.

B-Lymphocytes↗

Human monoclonal antibodies produced by primary in vitro immunization of peripheral blood lymphocytes.

A general procedure is described for the production of human monoclonal antibodies from peripheral blood lymphocytes immunized in vitro against T-cell-dependent antigens. These lymphocytes immunized in culture were used to produce human-human or human-mouse hybridomas secreting monoclonal antibodies specific for digoxin, hemocyanin, a recombinant fragment of the gp120 envelope glycoprotein of human immunodeficiency virus (PB1), or a melanoma-associated antigen (p97). Depletion of a lysosome-rich cell population, containing large granular lymphocytes, monocytes, cytotoxic T cells, and a subset of CD8-positive T cells, was shown to be crucial before the cells could be immunized in vitro. This depletion was accomplished by treating the peripheral blood lymphocytes with the lysosomotropic agent L-leucine methyl ester. In addition, the in vitro immunization had to be supported by interleukin 2, gamma-interferon, and B-cell growth and differentiation factors, derived from irradiated, pokeweed-mitogen-stimulated human T cells. The production of human monoclonal antibodies from primary, antigen-specifically activated peripheral lymphocytes might obviate the need to immunize volunteers or patients.

Antibodies, Monoclonal↗

Human monoclonal antibodies produced from L-leucine methyl ester-treated and in vitro immunized peripheral blood lymphocytes.

Primary in vitro immunization of peripheral blood lymphocytes has been studied for the production of human monoclonal antibodies. Depletion of a lysosome-rich cell population, containing large granular lymphocytes, monocytes, and a subset of T suppressor cells, was shown to be crucial before the cells could be immunized in vitro. The in vitro immunized lymphocytes were used to produce human x human and human x mouse hybridomas secreting monoclonal antibodies specific for digoxin, hemocyanin, or a recombinant fragment of gp120 of human immunodeficiency virus.

Antibodies, Monoclonal↗

Effect of cytokines on specific in vitro immunization of human peripheral B lymphocytes against T-cell dependent antigens.

The requirements for a primary, antigen-specific in vitro immunization of human peripheral lymphocytes using haemocyanin, a T-cell dependent antigen, have been studied. In order to obtain a specific response in vitro the peripheral lymphocytes had to be separated into B, T, accessory (A) and dendritic (D) cells. These cells were activated and reconstituted to give a population with a B:T ratio of 1:2. If the induction was supported by MHC-restricted, radioresistant T cells, this cell population could then be antigen-specifically activated using haemocyanin. The immunization had also to be supported by cytokines, such as B-cell growth and differentiation factors, interleukin-2 and gamma-interferon. A 5-day in vitro immunization using 2 micrograms haemocyanin/ml resulted in 200-300 cells secreting anti-haemocyanin-specific antibodies per 10(6) B cells.

Antibody-Producing Cells↗

Concanavalin A-induced B-cell proliferation mediated by allogeneically derived helper factors.

Highly purified, small, resting murine Ig-positive spleen cells could be induced to proliferate by concanavalin A (Con A) if the activation was supported by allogeneic helper factors (AHF). Con A or AHF alone was unable to induce cell proliferation as determined by incorporation of [methyl-3H] thymidine. However, if AHF produced by a mixed lymphocyte culture was present together with Con A, the B lymphocytes were strongly activated exhibiting a stimulation index of approximately 2000 as compared to Con A alone. The dose-response maximum was obtained after a 4-day culture using 25% of a supernatant from a mixed lymphocyte culture as a source of AHF. The kinetics of the AHF-supported B-cell activation was also investigated. The activation could be completely inhibited by the addition of 100 mM methyl alpha-D-mannopyranoside at the initiation of the culture, but, if added 14-18 hr later, the cells have had the necessary induction period and a proliferation could be recorded. AHF had to be present at the initiation of the cultures, otherwise the response immediately diminished, whereas Con A could be added up to 6 hr after initiation without affecting the proliferative response.

Animals↗

Prevalence of coxarthrosis.

In a survey of 4027 double-contrast colon roentgenograms, the hip joints were examined and classified with regard to the presence or absence of primary coxarthrosis. The hips were graded according to type and severity of coxarthrosis. The data collection was performed in precisely the same manner as in an earlier study undertaken on 3903 similar examinations that had been performed more than 20 years earlier. During this time period, the prevalence had not changed, nor was there any change in sex ratio or distribution between bilateral and unilateral cases or between types of coxarthrosis. Also, the severity of the coxarthrosis at the time of the examination was approximately the same. A considerable portion of the patients (including those in the present study), about one third, had not been previously diagnosed. In this group, mixed and medial coxarthrosis were more common among men than was lateral coxarthrosis. There was no difference in age or sex between previously diagnosed and undiagnosed groups of coxarthrosis. In the recent study, about one third of the patients had been treated mostly by total hip arthroplasty (THA). In these patients, lateral coxarthrosis was more common. Women were over-represented among the THA cases, even though the coxarthrosis was not more severe.

Adult↗