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Biomedical subjects

M Landgren

Publications and source records attributed to M Landgren.

14 recordsLinked to original sources
PubMed2006

Visual function and ocular features in children and adolescents with attention deficit hyperactivity disorder, with and without treatment with stimulants.

AIMS: To investigate visual function and ocular features in children with attention deficit hyperactivity disorder (AD/HD) and establish whether treatment with stimulants is reflected in functioning of the visual system. METHODS: Detailed ophthalmologic evaluations without and with stimulants were performed in 42 children (37 boys) with AD/HD, mean age 12 years, and compared with a reference group (ref; n=50; mean age 11.9 years; 44 boys). For a comparison between two groups, Mann-Whitney's U-test was used for ordered and continuous variables; for dichotomous variables, Fisher's exact test was used. For paired comparison (with and without treatment), sign test was used. RESULTS: In all, 83% had visual acuity of >0.8 (<0.1 logMAR) without treatment, 90% with stimulants (ref 98%; P=0.032 and n.s., respectively). Heterophoria was found in 29% without, and in 27% with, stimulants (ref 10%; P=0.038 and n.s., respectively) and subnormal stereovision (>60 s of arc) in 26% (ref 6%; P=0.016) without stimulants, and in 27%, with (P=0.014). Abnormal convergence (>6 cm or absent) was noted in 24% (ref 6%; P=0.031) without treatment and in 17%, with (n.s.). Astigmatism (> or =1.0 D) was observed in 24% (ref 6%; P=0.03), and signs of visuoperceptual problems in 21% (ref 2%; P=0.007). We found smaller optic discs (n=8/38) and neuroretinal rim areas (n=7/38) (P<0.0001) and decreased tortuosity of retinal arteries (n=6/34) (P=0.0002) than that of controls. CONCLUSIONS: Children with AD/HD had a high frequency of ophthalmologic findings, which were not significantly improved with stimulants. They presented subtle morphological changes of the optic nerve and retinal vasculature, indicating an early disturbance of the development of these structures.

Adolescent↗
PubMed2005

Diversity among 2481 Escherichia coli from women with community-acquired lower urinary tract infections in 17 countries.

OBJECTIVES: In the recently published ECO.SENS survey, the antimicrobial susceptibility of Escherichia coli from urinary tract infections in women in 16 European countries and Canada was investigated. This study reports the diversity among these E. coli. METHODS: The 2481 E. coli, typed with the PhenePlate (PhP) System utilizing the dynamics and end result of 11 biochemical reactions in a microplate system, were clustered and the Simpson's index of diversity calculated. RESULTS: Seventy-four Common PhP Types (CT) comprising 2067 isolates and 414 Single Types (Si) were identified. Of these, 916 isolates (37%) belonged to one of the four most frequent CT (arbitrarily numbered CT48, 10, 26 and 20). CT48 with 400 isolates and 11 different susceptibility patterns, was widely disseminated across Europe and Canada and was the most frequent type in 13 countries and the second most frequent in the remaining four countries. Sixty-four per cent of the E. coli were susceptible to all eight investigated antimicrobials (CT48: 73%, CT10: 77%, CT26: 62% and CT20: 37%). Forty-six different susceptibility patterns were seen, the three most common being isolated resistance to ampicillin, resistance to ampicillin and trimethoprim, and isolated resistance to trimethoprim. Multiresistance, here defined as resistance to four or more of the investigated antibiotics, was distributed among E. coli belonging to several PhP types. CONCLUSIONS: There was no obvious correlation between the phenotypes identified with the PhP System and the susceptibility pattern. The data did not indicate clonal dissemination within or between countries as a major reason for differences in antimicrobial resistance rates.

Adult↗
PubMed2004

Arabidopsis thaliana chromosome III restores fertility in a cytoplasmic male-sterile Brassica napus line with A. thaliana mitochondrial DNA.

Somatic Brassica napus (+) Arabidopsis thaliana hybrids with a cytoplasmic male sterility (CMS)-inducing cytoplasm were screened for fertility-restored plants. One line was selected and recurrently backcrossed with the maintainer line, B. napus, resulting in fertile/sterile segregating populations. Restriction fragment length polymorphism mapping showed the co-segregation of A. thaliana chromosome (chr) III markers with the fertility trait. As it was not possible to stabilise the fertility trait via selfings, a dihaploidisation strategy was assessed. Ninety haploid plants were regenerated and analysed with numerous simple sequence length polymorphism (SSLP) markers. Markers covering both arms of A. thaliana chr III were present in two plants, whereas no A. thaliana DNA could be detected in the other plants. Following colchicine-induced chromosome doubling only these two plants with A. thaliana DNA produced fertile offspring. In one of the two lines, however, the A. thaliana-specific DNA markers and fertility were lost in subsequent generations. The other line remained fertile after repeated selfings. Using genomic in situ hybridisation (GISH) we were able to demonstrate that this latter line possessed a disomic addition of the A. thaliana chromosome. The restored line was comparable to the maintainer line with respect to flower morphology, but the petals and stamens were slightly reduced in size. The homeotic conversion of stamens to pistil-like structures, which is typical for the CMS line, was reversed, and stamens with a normal appearance with viable pollen appeared. Flowering time was as in the CMS line-in both lines it was delayed in comparison to the maintainer line. The introgressed chromosome also contributes to several pleiotropic effects, such as reduced leaf crinkling and shorter stems. The ability to restore fertility through the introgression of nuclear genes from the main cytoplasmic donor species indicates that the CMS trait in this system mainly is due to B. napus/ A. thaliana alloplasmic incompatibility and not mitochondrial DNA rearrangements. Further exploitation of the material is discussed.

Arabidopsis↗
PubMed2004

Visual and ocular findings in children adopted from eastern Europe.

AIMS: To evaluate ophthalmological findings in children adopted from eastern Europe. METHODS: A prospective study on 72/99 children, born 1990-5 and adopted from eastern Europe to western Sweden during 1993-7 was performed. The children (41 boys; mean age 7.5 years) were compared with an age and sex matched reference group ("ref") of Swedish children. RESULTS: 78% of the adopted children had abnormal ocular findings. 26% (ref 4%) had visual acuity (VA) of the better eye < or = 0.5 (> or = 0.3 logMAR) (p = 0.0001) and 8% (ref 0%) were visually impaired (p = 0.01). Amblyopia was found in 15% (ref 2%) (p = 0.005). 22% (ref 10%) were hyperopic (> or = 2.0 D SE) (NS) and 10% (ref 1%) were myopic (> or = 0.5 D SE) (p = 0.03). Astigmatism (> or = 0.75 D) was found in 51% (ref 23%) (p = 0.004). 32% (ref 2%) had strabismus (p<0.0001), mostly esotropia. Four cases had bilateral optic nerve hypoplasia, in three of whom a history of suspected prenatal alcohol exposure was documented. One child had congenital glaucoma. Signs of visuoperceptual problems were recorded in 37% (ref 1%) (p<0.0001). CONCLUSION: In this study, children adopted from eastern Europe had a high frequency of ophthalmological findings. Consequently, it is strongly recommended that an ophthalmological examination be performed in these children after arrival in their new home country.

Adoption↗
PubMed2003

"A school for all kinds of minds." The impact of neuropsychiatric disorders, gender and ethnicity on school-related tasks administered to 9-10-year-old children.

This cross-sectional study of reading,writing and mathematics skills in a total population of 589 children attending 4th grade in regular public schools showed that neuropsychiatric disorder was a strong predictor of poor performance, girls scored better than boys on language tests and some mathematics test, and immigrant children had similar results as native Swedish children on most tests. Sixty percent of boys with and 7% of boys without DAMP (Deficits in Attention,Motor control and Perception) or ADHD (Attention- Deficit/Hyperactivity Disorder) had substantial school difficulties. The rate of children requiring individualised special education measures was estimated at a minimum of 15%. This constitutes a major challenge to a society claiming to offer equal opportunities and participation for all children.

Attention Deficit Disorder with Hyperactivity↗
PubMed2002

Brassica napus lines with rearranged Arabidopsis mitochondria display CMS and a range of developmental aberrations.

Numerous Brassica napus (+) Arabidopsis thaliana somatic hybrids were screened for male sterility and aberrant flower phenotypes. Nine hybrids were selected and backcrossed recurrently to B. napus. The resulting lines displayed stable maternal inheritance of flower phenotypes. Nuclear and organellar genomes were characterized molecularly using RFLP analysis. No DNA from A. thaliana was found in the nuclear genome after six back-crosses, whilst the mitochondrial genomes contained rearranged DNA from both A. thaliana and B. napus. Each line tested had a unique RFLP pattern of the mitochondrial DNA (mtDNA) that remained unchanged between the BC(3) and BC(6) generation. The plastid genomes consisted of B. napus DNA. Five lines of the BC(5) generation were subjected to more comprehensive investigations of growth, morphology and fertility. On the basis of these investigations, the five CMS lines could be assigned to two groups, one represented by three lines displaying reduced vegetative development, complete male sterility, and homeotic conversions of stamens into feminized structures. The second group, represented by the other two lines, were not completely male-sterile but still displayed severely affected flower morphologies. These two lines did not display any reduction in vegetative development. For both groups only stamens and petals suffered from the morphological and functional aberrations, while the sepals and pistils displayed normal morphology. All plants were fully female-fertile. Different rearrangements of the mitochondrial genome disturbed nuclear-mitochondrial interactions and led to various types of aberrant growth and flower development. The existence of numerous CMS lines with different mitochondrial patterns involving a species with a sequenced genome offers new opportunities to investigate the genetic regulation of CMS and its associated developmental perturbations.

Arabidopsis↗
PubMed2001

Parametric control of fingertip forces during precision grip lifts in children with DCD (developmental coordination disorder) and DAMP (deficits in attention motor control and perception).

Twenty boys with developmental coordination disorder (DCD), 11 of whom had associated attention deficit disorder (ADD), were compared with an age-matched control group of 12 boys to examine mechanisms that adapt the grip force at the digit-object interface in a precision grip task. An experimental grip object equipped with pressure transducers registered the grip forces (normal to the surface) and the load force (tangential to the surface) generated by the fingertips. The surface of the object was changed to vary the frictional properties. Both study groups exhibited disturbances of the basic coordination of forces in the initial phase of the movement, manifested by longer time latencies and higher force levels than the control group. All subjects were able to adapt the force output in response to the friction at the digit-object interface. Higher grip forces and safety margins were documented for the DCD group in comparison to the controls. Furthermore, there was greater variation in the parametric control of the grip force in the DCD group. The results suggest that the control of the grip force is similar in children with DCD, regardless of whether they have associated ADD or not, but it is impaired in comparison to that of controls.

Attention Deficit Disorder with Hyperactivity↗
PubMed2000

Deficits in attention, motor control and perception (DAMP): a simplified school entry examination.

OBJECTIVE: To suggest an empirically based school entry screening examination for the detection of deficits in attention, motor control and perception (DAMP) in 6-y-old children. MATERIAL AND METHODS: A population-based cohort of 113 children, 6-7 y of age (62 with and 51 without DAMP), compared on measures of attention, motor functions, language and cognition. RESULTS: Attention deficits were convincingly identified by both parents and paediatrician. The motor function tests clearly distinguished between the two groups. Linguistic and meta-linguistic tests demonstrated greater phonological processing difficulties in the DAMP group. The cognitive test revealed an overall lower IQ but no consistent characteristic pattern in the DAMP group. CONCLUSIONS: A simplified paediatric school entry examination test is suggested. Four motor tests (standing on one foot, Fog test, design copying and diadochokinesis) administered by the paediatrician, combined with a brief structured clinical observation and a structured parent interview, identified 80% of children with DAMP-and all those with severe DAMP-as well as a small number of false positives.

Attention Deficit Disorder with Hyperactivity↗
PubMed1998

Attention deficit disorder with developmental coordination disorders.

AIMS: To analyse the contribution of certain social, familial, prenatal, perinatal, and developmental background factors in the pathogenesis of deficits in attention, motor control, and perception (DAMP). METHODS: A population based case-control study was carried out with 113 children aged 6 years, 62 diagnosed with DAMP and 51 controls without DAMP. The children's health and medical records were studied and their history with regard to background factors was taken at an interview with the mother using a standardised schedule. Familial factors, possible non-optimal factors during pregnancy (including smoking), developmental factors (including early language development), and medical and psychosocial data were scored in accordance with the reduced optimality method. RESULTS: Low socioeconomic class was common in the group with DAMP. Familial language disorder and familial motor clumsiness were found at higher rates in the DAMP group. Neuropathogenic risk factors in utero were also more common in the children with DAMP. Maternal smoking during pregnancy appeared to be an important risk factor. Language problems were present in two thirds of the children with DAMP. Sleep problems and gastrointestinal disorders, but not atopy or otitis media, were significantly more common in the DAMP group. CONCLUSIONS: Prenatal familial and neuropathogenic risk factors contribute to the development of DAMP. Primary prevention, such as improved maternal health care and early detection or treatment, or both, of associated language problems appear to be essential.

Attention Deficit Disorder with Hyperactivity↗
PubMed1996

Alloplasmic male-sterile Brassica lines containing B. tournefortii mitochondria express an ORF 3' of the atp6 gene and a 32 kDa protein. off.

Analyses of mitochondrial transcription and in organello translation were performed with the Brassica tournefortii cytoplasm. This cytoplasm causes alloplasmic male sterility when combined with the nuclear genomes of B. napus and B. juncea. Mitochondrial RNA and protein banding patterns were compared between the fertile wild species B. tournefortii, an alloplasmic male-sterile B. juncea line, an alloplasmic male-sterile B. napus line and an alloplasmic B. napus line with restored fertility. The analyses were carried out to identify differences in gene expression and to investigate whether alterations in gene expression accompanied male sterility. A difference in transcription patterns between the fertile B. tournefortii and the alloplasmic lines was found for the atp6 gene. The atp6 region was investigated further, since a similar alteration in atp6 transcription has been observed in two other Brassica cytoplasms which are associated with cytoplasmic male sterility (CMS). The additional longer atp6 transcript detected in the alloplasmic lines in the present study was found to contain an open reading frame (ORF) located downstream of the atp6 gene. DNA sequencing revealed that the ORF, orf263, could encode a protein with a predicted molecular weight of about 29 kDa. In organello analysis detected two proteins of 29 and 32 kDa respectively, which were found only in the alloplasmic lines. Furthermore, the 32 kDa protein accompanied male sterility since it was absent in alloplasmic plants restored to fertility. The protein analysis might indicate that orf263 is translated and causes CMS.

Amino Acid Sequence↗
PubMed1996

ADHD, DAMP and other neurodevelopmental/psychiatric disorders in 6-year-old children: epidemiology and co-morbidity.

A total population of 589 6-year-old children were screened for neurodevelopmental/neuropsychiatric disorders by questionnaires to parents and preschool teachers, and by examination of motor abilities at the Child Health Center. Fifty screen-positive and fifty screen-negative children were assigned for complete neuropsychiatric assessment comprising a detailed history, psychiatric and neurodevelopmental assessment, neuropsychological examination and speech/language evaluation. Comprehensive diagnoses were made on the basis of all the available information. In the total population, 63 children (10.7%) with disorders were identified, 10 of whom had a diagnosis established before the study. The prevalence rates for deficits in attention, motor control and perception (DAMP) were 5.3 to 6.9%, for attention deficit hyperactivity disorder (ADHD) they were 2.4 to 4.0% and for mental retardation, 2.5%. Co-morbidity was established for ADHD on the one hand and DAMP, mental retardation and Tourette syndrome on the other. The findings suggest the need for a school entrant screening examination for the types of problems examined in this study.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

Diagnosis of Epstein-Barr virus-induced central nervous system infections by DNA amplification from cerebrospinal fluid.

A nested polymerase chain reaction was used for the detection of Epstein-Barr virus DNA in 1 patient with encephalitis, and in 1 patient with myelitis. Epstein-Barr virus DNA was detected in cerebrospinal fluid samples obtained at the onset of neurological symptoms in both patients, and serological findings indicated ongoing Epstein-Barr virus infection. In the patient with encephalitis, herpes simplex virus type 1 DNA was transiently detected in the cerebrospinal fluid, while Epstein-Barr virus DNA was still present on day 44 after admittance. Single-photon emission computed tomography in this patient indicated a frontal bilateral hypoperfusion. The diagnostic value of polymerase chain reaction on cerebrospinal fluid and serum samples for Epstein-Barr virus infections of the central nervous system is emphasized.

Adolescent↗
PubMed1992

Goldenhar syndrome and autistic behaviour.

Two girls with concomitant Goldenhar syndrome (oculo-auriculovertebral spectrum disorder) and autistic disorder are described. One was diagnosed as having Goldenhar syndrome in the first few weeks of life and as having autistic disorder in her fifth year; the other was diagnosed as having Goldenhar syndrome when she was referred for evaluation of autistic symptoms at seven years of age. The type of physical abnormalities encountered in Goldenhar syndrome suggests damage to neural structures in the second or late stages of the first trimester. The two cases described in this report suggest that autistic disorder sometimes can result from neural damage during the second trimester.

Autistic Disorder↗