PubMed Health⌕ Search

Biomedical subjects

H Janson

Publications and source records attributed to H Janson.

At least 19 recordsLinked to original sources
PubMed2004

Parent-completed developmental screening in a Norwegian population sample: a comparison with US normative data.

AIM: To compare normative data of a Norwegian translation of the Ages and Stages Questionnaires with original US normative data. METHODS: Norwegian-born mothers randomly selected from the population register completed Norwegian translations of the Ages and Stages Questionnaires, a series of 19 age-specific child development screening questionnaires each made up of 30 items in five domains: Communication, Gross Motor, Fine Motor, Problem Solving, and Personal-Social. Domain score group differences with original US normative data on 10 age-specific questionnaires (for ages 4, 8, 12, 16, 20, 24, 30, 36, 48, and 60 mo) were investigated. The Norwegian data consisted of 1341 children, varying between 82 and 176 per age interval. RESULTS: On the whole, parents' reports of their children's development were very similar in the two data sets. Only five out of 50 mean comparisons revealed a mean difference either greater than a Cohen's d of 0.5 or greater than the smallest increment on a domain score. The variation in scores tended to be somewhat smaller in the Norwegian sample. CONCLUSION: It seems reasonable to expect that domain scores on the Ages and Stages Questionnaires may be interpreted in the same way in Norway and the United States, and these results may also generalize to other Western settings. These findings from a true random sample also increase the confidence in the original normative data.

Child Development↗
PubMed2003

Influences on participation rate in a national Norwegian child development screening questionnaire study.

AIM: To describe the influence of demographic variables on participation rate in a child development screening questionnaire study, and to discuss the implications for data analysis and for the design of future similar studies. METHODS: Appropriate Ages and Stages Questionnaires were mailed to 2392 mothers of children aged 4-60 mo. The bivariate and multivariate influence of demographic variables on responding was investigated. RESULTS: The response rate decreased roughly linearly with the age of the child (ranging from 76% at 8 mo to 32% at 60 mo). Mother's educational level, civil status and (marginally) child's gender also contributed independently to the prediction of response. CONCLUSION: Participation rate may be interpreted in terms of interest/saliency and time demands, if a mother's interest in her baby's normative development is assumed to be great, though decreasing as the child grows. Weighting for demographic variables seems to be a viable procedure in the present project; future studies may consider measures to increase the immediacy of questionnaire completion for mothers of children aged 3 y and older.

Child↗
PubMed2001

Isolation and characterization of a novel IgD-binding protein from Moraxella catarrhalis.

A novel surface protein of the bacterial species Moraxella catarrhalis that displays a high affinity for IgD (MID) was solubilized in Empigen and isolated by ion exchange chromatography and gel filtration. The apparent molecular mass of monomeric MID was estimated to approximately 200 kDa by SDS-PAGE. The mid gene was cloned and expressed in Escherichia coli. The complete mid nucleotide gene sequence was determined, and the deduced amino acid sequence consists of 2123 residues. The sequence of MID has no similarity to other Ig-binding proteins and differs from all previously described outer membrane proteins of M. catarrhalis. MID was found to exhibit unique Ig-binding properties. Thus, in ELISA, dot blots, and Western blots, MID bound two purified IgD myeloma proteins, four IgD myeloma sera, and finally one IgD standard serum. No binding of MID was detected to IgG, IgM, IgA, or IgE myeloma proteins. MID also bound to the surface-expressed B cell receptor IgD, but not to other membrane molecules on human PBLs. This novel Ig-binding reagent promises to be of theoretical and practical interest in immunological research.

Adhesins, Bacterial↗
PubMed2001

Protein D expression promotes the adherence and internalization of non-typeable Haemophilus influenzae into human monocytic cells.

Protein D, having a glycerol-3-phosphodiester phosphodiesterase activity, is found at the surface of all Haemophilus influenzae strains and is a possible virulence factor. In the present study, the involvement of protein D in the entry of NTHi into human monocytic cells is reported. Primary monocytes and the monocytic cell lines U-937 and THP-1 were infected with NTHi strain 772 and the mutant 772 Delta hpd 1 (lacking the gene for protein D). NTHi 772 adhered to and entered monocytic cells up to four-fold more efficiently compared to 772 Delta hpd 1. When an Escherichia coli transformant expressing protein D was incubated with monocytic cells, the number of intracellular bacteria increased 1.6-fold compared to protein D-deficient controls. Any correlation between internalization and phosphorylcholine expression was not detected. In conclusion, our data suggest that surface-expressed protein D promotes the adherence of NTHi to human monocytes leading to a higher number of internalized bacteria.

Bacterial Adhesion↗
PubMed2001

Childhood sexual abuse, parenting and postpartum depression--a 3-year follow-up study.

OBJECTIVE: This study is the second and final phase of a 3-year follow-up study of women who had been admitted with a major depressive episode in the postpartum period, along with their children and partners where present. The effect of a maternal sexual abuse history on the women's well-being and child outcome compared to those women without such a history is highlighted. METHOD: Forty-five of an original cohort of 56 women were seen with their child where possible, when the child was an average of 36.8 months old. Twenty-two women had no history of sexual abuse, and 23 gave a history of childhood sexual abuse. Women were assessed with respect to well-being, relationships, parenting stress and psychiatric history since recruitment. The child's behavior and cognitive development was also assessed. RESULTS: Women with a history of sexual abuse rated higher depression and anxiety scores (p < .05), and had greater life stresses (p < .05). Their partners rated themselves as more comforting and their children as more disturbed (p < .05). Over time, this group had failed to improve as much as the nonabuse group on these measures. There was no difference in child cognitive scores between groups. CONCLUSIONS: A history of sexual abuse in women who become depressed postpartum may have long term implications for the woman's mental health, her relationship with her child, as well as the emotional development of her child. It is critical to offer women in this high-risk group supports in an attempt to minimize these difficulties and any long-term adverse effects.

Adult↗
PubMed1999

Fragmentation heterogeneity of 23S ribosomal RNA in Haemophilus species.

The fragmentation of 23S rRNA of 23 Haemophilus influenzae strains and eight strains belonging to other Haemophilus species was investigated. Instead of intact molecules, the 23S rRNA molecules were found to be cleaved into two to five smaller conserved fragments in most strains examined, especially in H. influenzae type b (5/6) and nontypeable strains (5/5). One or two conserved potential cleavage sites were identified by PCR analysis of the strains showing a fragmented 23S rRNA pattern. The relevant nucleotide sequences were determined and compared to H. influenzae Rd, which contains intact 23S rRNA molecules. An identical 112bp long intervening sequence (IVS) at position 542 and a conserved 121-123bp IVS sequence at position 1171 were found in two H. influenzae type b strains and one nontypeable strain. Among the strains with fragmented 23S rRNA, nearly half showed a heterogeneous cleavage pattern due to the dispersion of IVSs among different 23S rRNA operons. The localization of the conserved H. influenzae IVSs coincided well with the extensively studied IVSs among other bacteria, but differed in nucleotide sequence from any other reported IVSs. Therefore, the IVSs of Haemophilus 23S rRNA may originate from a common source that is independent of other bacteria.

Base Sequence↗
PubMed1999

Effects on the ciliated epithelium of protein D-producing and -nonproducing nontypeable Haemophilus influenzae in nasopharyngeal tissue cultures.

A pair of isogenic, nontypeable Haemophilus influenzae strains, one expressing protein D and the other protein D-negative, was compared in their ability to cause damage in a human nasopharyngeal tissue culture model. Damage was assessed by measuring the ciliary beat frequency (CBF) of tissue specimens at 12 h intervals. Cultures inoculated with H. influenzae manifested a decrease in CBF beginning after 12 h, with a maximum decrease after 36 h. The impairment of ciliary function by the protein D-expressing strain was significantly greater than that caused by the protein D-negative mutant (P<.01). Tissue specimens examined by scanning and transmission electron microscopy after 24 h appeared normal. After 48 h of incubation, the protein D-expressing strain caused a significant loss of cilia. These findings suggest that protein D is involved in the pathogenesis of upper respiratory tract infections due to nontypeable H. influenzae, probably by enhancing functional and morphological damage to cilia.

Adenoids↗
PubMed1998

Glycerol-3-phosphate transport in Haemophilus influenzae: cloning, sequencing, and transcription analysis of the glpT gene.

The presence of a functional glpT gene in Haemophilus influenzae could be questioned, since there is only what appears to be a truncated glpT (HI0686, 143 nt in the 5'-end) available in the H. influenzae Rd genome database (Fleischmann et al. , 1995). For cloning of the glpT gene from H. influenzae type b strain Eagan, an isogenic glpT, rec-1 double mutant and a selective medium for detection of the glpT mutant strains were constructed. The recombinant plasmid carrying glpT was able to complement the isogenic glpT mutant to wild-type levels of G3P uptake and permitted growth on a selective medium with G3P as a major carbon source. The nucleotide sequences of the glpT gene were determined both directly from PCR products and from the cloned DNA insert of strain Eagan. An identical 1440 bp open reading frame with 480 deduced amino acids, highly homologous to other bacterial G3P permeases, was identified. A Northern blot analysis showed that the glpT genes in both Eagan and Rd strains were transcribed on a RNA of approximately 1.4 kb in size. Thus, it is likely that HI0686 sequence originates from a mutated glpT clone in Escherichia coli.

Amino Acid Sequence↗
PubMed1997

Amoxicillin treatment of experimental acute otitis media caused by Haemophilus influenzae with non-beta-lactamase-mediated resistance to beta-lactams: aspects of virulence and treatment.

Through alterations primarily in the penicillin-binding proteins, a non-beta-lactamase-mediated resistance to beta-lactams has evolved in Haemophilus influenzae. The virulence of these chromosomally changed strains has been questioned. To ascertain whether these alterations involve a reduction in virulence of H. influenzae and whether they could be advantageous for the bacterium during amoxicillin treatment of acute otitis media, a total of 70 Sprague-Dawley rats were challenged with a susceptible recipient strain or a genetically similar resistant transformant strain. Antibiotic therapy was started on day 3 after inoculation, and the animals were monitored by daily otomicroscopy and analysis of bacterial samples from middle ear effusions obtained on day 8, the last day of observation. The animals were also sacrificed on days 4 and 8 and after 2 months for morphological examination. Compared with the susceptible recipient strain, recovery from infections caused by the resistant transformant strain was delayed, and the late structural changes were more severe in the animals challenged with the latter strain. The results of the study indicate that chromosomal alterations mediating a relatively low level of resistance to beta-lactams may be advantageous for H. influenzae during antibiotic treatment of a local infection in the rat, and the alterations may occur without any significant loss of virulence.

Acute Disease↗
PubMed1996

Biological activity of serum antibodies to a nonacylated form of lipoprotein D of Haemophilus influenzae.

Protein D, a surface-exposed 42-kDa membrane lipoprotein, is well conserved among both type b and nontypeable Haemophilus influenzae strains, and it is considered a vaccine against H. influenzae infections. Here, we report the large-scale purification of a nonacylated form of protein D (PDm) from the periplasmic space of Escherichia coli overexpressing PDm. Screening of human sera for levels of antibodies to PDm demonstrated that the immunoglobulin G (IgG) antibody level is above background levels in infants less than 6 months of age. Following a drop to background values in the age group 6 months to 1 year, IgG antibody levels start to increase, together with IgA antibody levels, after 1 year of age. The first appearance of serum IgM antibodies is in 6-month- to 1-year-old infants whose IgG antibody levels have dropped to the postnatal background level. Affinity-purified antibodies from humans and from PDm-immunized rats detected epitopes of protein D which are normally exposed on the bacterial surface. Affinity-isolated human anti-PDm antibodies eluted in acidic buffer were not bactericidal against H. influenzae. Loss of bactericidal activity may occur in this buffer, as was demonstrated in pooled human sera with high bactericidal activity after incubation in the same buffer. Hyperimmunization of rats with PDm induced high levels of serum IgG and IgA antibodies against PDm and significant bactericidal activity against homologous and heterologous H. influenzae strains.

Acylation↗
PubMed1995

The gene encoding protein D (hpd) is highly conserved among Haemophilus influenzae type b and nontypeable strains.

The molecular conservation of a surface-exposed lipoprotein, protein D, of Haemophilus influenzae was studied by cloning and sequencing of the gene encoding protein D from three encapsulated type b strains and three nontypeable strains of H. influenzae. These nucleotide sequences were analyzed with previously reported sequences from one type b strain and one nontypeable strain. The nucleotide sequences and the deduced amino acid sequences for protein D were highly conserved. The deduced amino acid sequence (364 amino acids) of protein D from six strains differed only in two amino acids near the C-terminal end. The remaining two strains, one type b and one nontypeable, differed from the consensus sequence in 7 amino acids each. Protein D is 64 and 36% identical and 77 and 56% similar to the glycerophosphodiester phosphodiesterases (GlpQ) of Escherichia coli and Bacillus subtilis.

Amino Acid Sequence↗
PubMed1995

Effect of exposure to dothiepin and northiaden in breast milk on child development.

BACKGROUND: This study looks at the outcome of infants exposed to dothiepin in breast milk in an attempt to guide clinicians on the risk-benefit ratio of breast-feeding when on antidepressants. METHOD: Thirty women, who had had HDRS scores > 15 within the first five years postpartum from the same women's hospital, were assessed with their children 3-5 years postpartum; half had breast-fed while on dothiepin (study group). Thirty-six non-depressed women were also assessed. Rating scales assessed depression, anxiety, self-esteem, personality, social support, marital relationship, child behaviour and temperament. The children were assessed by the McCarthy Scale. RESULTS: Comparisons of the two depressed groups showed no significant differences on any measures except marital conflict and child behaviour, which were the most disturbed in the study group (P < 0.001). Overall cognitive scores for the children did not differ between the groups. Higher levels of dothiepin and northiaden were associated with higher cognitive scores on subscales (P = 0.02). CONCLUSIONS: We are cautiously optimistic about the lack of any negative associations between cognitive development and exposure to dothiepin via breast milk.

Antidepressive Agents, Tricyclic↗
PubMed1994

Protein D, the glycerophosphodiester phosphodiesterase from Haemophilus influenzae with affinity for human immunoglobulin D, influences virulence in a rat otitis model.

A mutant lacking the ability to express the surface-exposed lipoprotein protein D was constructed by linker insertion and deletion mutagenesis of a cloned DNA insert containing the protein D structural gene from a nontypeable Haemophilus influenzae strain (NTHi). An isogenic NTHi mutant was isolated after transformation of genetically competent bacteria. The transformant was unreactive to a protein D-specific monoclonal antibody in a colony immunoassay. In addition, the mutant lacked the ability to synthesize detectable levels of protein D by protein staining, immunoblot methods, glycerophosphodiester phosphodiesterase activity, and binding studies of radiolabelled immunoglobulin D. The isogenic protein D-deficient mutant was compared with its parental strain for its ability to induce experimental otitis media in rats challenged with bacteria. An approximately 100-times-higher concentration of the mutant compared with that of the wild-type strain was required in order to cause otitis among all rats challenged with that given dose. The protein D mutant exhibited a generation time that was equal to that of the wild-type strain in complex broth medium. No difference in lipopolysaccharide expression was found between the mutant and the parental strain. These results suggest that protein D may influence the pathogenesis of NTHi in the upper respiratory tract.

Animals↗
PubMed1993

Limited diversity of the protein D gene (hpd) among encapsulated and nonencapsulated Haemophilus influenzae strains.

Protein D is a surface-exposed lipoprotein of the gram-negative bacterium Haemophilus influenzae with affinity for human immunoglobulin D myeloma protein. The gene encoding protein D (hpd) in a serotype b strain of H. influenzae was cloned. Escherichia coli carrying the hpd gene bound human myeloma immunoglobulin D. Nucleotide sequence analysis identified an 1,092-bp open reading frame that was more than 99% identical to the hpd gene from a nontypeable H. influenzae strain. In the deduced amino acid sequences for protein D, only 2 of 364 amino acid residues differed. The restriction fragment length polymorphism of the hpd region in different strains was analyzed by Southern blot analyses of PstI- or EcoRI-digested genomic DNA from 100 H. influenzae strains. The analysis was performed by using isolated fragments of the cloned hpd gene, originating from the nontypeable H. influenzae 772, as probes. All strains tested had DNA sequences with a high degree of homology to the hpd probes. The analysis also showed that restriction endonuclease sites within the gene were more conserved than sites adjacent to the hpd gene. An interesting difference between type b strains and unencapsulated strains was observed. The majority of type b strains seem to have a 1.4-kbp DNA fragment upstream of the hpd gene that is absent in nontypeable strains. On the basis of the high degree of conservation of the hpd gene among H. influenzae strains, we conclude that protein D is a possible vaccine candidate.

Amino Acid Sequence↗
PubMed1992

Protein D, the immunoglobulin D-binding protein of Haemophilus influenzae, is a lipoprotein.

Protein D is an immunoglobulin D-binding membrane protein exposed on the surface of the gram-negative bacterium Haemophilus influenzae. Results reported here indicate that protein D is a lipoprotein. The protein is apparently synthesized as a precursor with an 18-residue-long signal sequence modified by the covalent attachment of both ester-linked and amide-linked palmitate to the cysteine residue, which becomes the amino terminus after cleavage of the signal sequence. Globomycin inhibited maturation of protein D in H. influenzae, implying that protein D is exported through the lipoprotein export pathway. A mutant expressing a protein D lacking the cysteine residue was constructed by oligonucleotide site-directed mutagenesis. The mutated protein D molecule was not acylated and partitioned in the aqueous phase after Triton X-114 extraction of intact bacteria, unlike native and recombinant protein D, which partitioned in the detergent phase. The nonacylated protein D molecule was localized to the periplasmic space of Escherichia coli. The hydrophilic protein D molecule will be used in investigations concerning its ability to function as a vaccine component.

Amino Acid Sequence↗
PubMed1991

Protein D, an immunoglobulin D-binding protein of Haemophilus influenzae: cloning, nucleotide sequence, and expression in Escherichia coli.

The gene for protein D, a membrane-associated protein with specific affinity for human immunoglobulin D, was cloned from a nontypeable strain of Haemophilus influenzae. The gene was expressed in Escherichia coli from an endogenous promoter, and the gene product has an apparent molecular weight equal to that of H. influenzae protein D (42,000). The complete nucleotide sequence of the gene for protein D was determined, and the deduced amino acid sequence of 364 residues includes a putative signal sequence of 18 amino acids containing a consensus sequence, Leu-Ala-Gly-Cys, for bacterial lipoproteins. The sequence of protein D shows no similarity to those of other immunoglobulin-binding proteins. Protein D is the first example of immunoglobulin receptors from gram-negative bacteria that has been cloned and sequenced.

Amino Acid Sequence↗