Biomedical subjects

S Andersson

Publications and source records attributed to S Andersson.

At least 19 recordsLinked to original sources

PubMed2006

Leakage of O2 precursor molecules from inert hydrogen islands on a Pt(111) surface.

We have observed, using infrared spectroscopy, that the precursor-mediated O2 chemisorption on the clean and the partially hydrogen-covered Pt(111) surfaces exhibits opposite temperature dependencies above the temperature for stable O2 physisorption. While the chemisorption probability on the clean surface increases with increasing temperature due to thermal activation of the precursor, it decreases on the partially hydrogen-covered surface which we suggest is due to a general loss of the mobile precursor molecules by thermal desorption from chemically inert hydrogen islands.

Journal Article↗

PubMed2006

Molecular hydrogen adsorption at surface adatoms.

Using electron-energy-loss spectroscopy, we have measured preferential adsorption of molecular hydrogen at Cu and Au adatoms deposited on a cold Cu(100) surface. We show, with particular attention to the D(2)-Au system, that the molecules adsorb at the adatoms, with an enhanced binding energy. The adsorption state is not of chemisorption character, the D(2) rotational and internal vibrational transition energies are close to the corresponding gas phase values, a characteristic property of a physisorbed state. A revealing signature of the D(2)-Au interaction is an induced dipole activity of the rotational transition, which discriminates molecules adsorbed at the adatoms from those adsorbed on the bare substrate surface. The average number of molecules per Au atom depends on the Au coverage and increases at lower coverages, for example, at 4% of an adatom monolayer, there are approximately six D(2) molecules per Au adatom. In this limit, Au monomers prevail, and a cluster of six D(2) around a single Au adatom appears to be an optimal dense two-dimensional configuration.

Journal Article↗

PubMed2006

Dipole active vibrations and dipole moments of N2 and O2 physisorbed on a metal surface.

We have, in infrared reflection absorption measurements, observed narrow dipole active absorption lines associated with the fundamental internal vibrational transitions of N(2) and O(2) physisorbed at 30 K on the chemically inert Pt(111)(1 x 1)H surface. Such transitions are forbidden for free homonuclear molecules and become dipole active at a metal surface due to polarization induced surface dipole moments. The measurements show that the internal stretch vibration frequencies are lowered by 7-8 cm(-1) relative to the gas phase values. The measured static and dynamic dipole moments are in the ranges of 0.06-0.07 and 0.001-0.002 D, respectively. We find that good estimates of the induced dynamic as well as the static dipole moments can in general be obtained from a van der Waals model but that the ratios of the measured static and dynamic moments indicates a need for a refinement of the dipole moment function.

Journal Article↗

PubMed2006

Frequent gain of the human telomerase gene TERC at 3q26 in cervical adenocarcinomas.

The level of genomic amplification of the human telomerase gene TERC, which maps to chromosome band 3q26, was determined in primary cervical adenocarcinomas. Interphase nuclei prepared from archival material of 12 primary cervical adenocarcinomas, eight of which were human papillomavirus positive, were hybridised with a triple colour probe set specific for centromeres of chromosomes 3 and 7 and the TERC gene. We observed high proportions of nuclei with increased absolute copy numbers for TERC in all tumours (mean 3.3; range 2.3-5.2). Amplification of the human telomerase gene TERC is a consistent aberration in cervical adenocarcinomas. Therefore, application of our probe set may provide an objective genetic test for the assessment of glandular cells in Pap smears and hence for the diagnosis of cervical adenocarcinomas.

Adenocarcinoma↗

PubMed2006

Mitochondrial myopathy with exercise intolerance and retinal dystrophy in a sporadic patient with a G583A mutation in the mt tRNA(phe) gene.

We describe a second patient with the 583G>A mutation in the tRNA(phe) gene of mitochondrial DNA (mtDNA). This 17-year-old girl had a mitochondrial myopathy with exercise intolerance and an asymptomatic retinopathy. Muscle investigations showed occasional ragged red fibers, 30% cytochrome c oxidase (COX)-negative fibers, and reduced activities of complex I+IV in the respiratory chain. The mutation was heteroplasmic (79%) in muscle but undetectable in other tissues. Analysis of single muscle fibers revealed a significantly higher level of mutated mtDNA in COX-negative fibers. Our study indicates that the 583G>A mutation is pathogenic and expands the clinical spectrum of this mutation.

Adolescent↗

PubMed2006

Parallel cyclin E and cyclin A expression in neoplastic lesions of the uterine cervix.

Cyclin E levels are high during late G1 and early S-phase in normal cells. The cyclin E expression over the cell cycle in tumours is not fully known. The impact on patient outcome by high cyclin E levels during other parts of the cell cycle than late G1- and early S-phase is unknown. We set out to study the expression of cyclin E over the cell cycle in cervical carcinomas. Using immunofluorescence staining of cyclin A, digital microscopy, and digital image analysis, we determined which cells in a tissue section that were in S- or G2-phase. M-phase cells were detected by morphology. By simultaneously staining for cyclin E, we investigated the variation in cyclin E levels over the cell cycle in cervical carcinoma lesions. In a case-control study, in which each deceased patient was matched with a patient still alive and well after >5 years of follow-up, we found that the deceased patients had a considerably higher fraction of cyclin A-positive cells staining for cyclin E than the survivors (n = 36). We conclude that parallel cyclin E and cyclin A expression is an indicator for poor outcome in cervical carcinomas. In addition, we investigated the expression pattern of cyclin E and cyclin A in consecutive biopsy samples from cervical carcinomas at different stages, as well as in human papillomavirus positive or negative adenocarcinomas in order to further study the cyclin E and cyclin A expression pattern in neoplastic lesions of the uterine cervix.

Adenocarcinoma↗

PubMed2006

Selective adsorption, bound states, and potential parameters for He, Ne, and Ar interacting with a Cu(110) surface.

Using nozzle beams of He, Ne, and Ar, we have measured diffractive selective adsorption resonances from a Cu(110) surface kept at 20 K. Bound state energies of the atom-surface potentials have been determined from plots of the measured resonance energies versus incident angle and their fits to calculated kinematical dispersion relations. For 3He and 4He we have found a unique level assignment that is compatible with a single gas-surface potential curve with a well depth of 6.05 meV of the He-Cu(110) potential. This value is about 10% larger than the prediction of 5.55 meV from the current physisorption theory. The Ne and Ar data reveal a large number of closely spaced levels with level separations and estimated van der Waals coefficients that are compatible with available theoretical data.

Journal Article↗

PubMed2006

High-resolution resonance measurements of the physisorption interaction.

Narrow selective adsorption resonances, with line widths given by the natural lifetime of the intermediate resonance state, have been observed directly in the angular distributions of Ne nozzle beams diffracted from a 20 K Cu(110) surface. Using beams of 20Ne and 22Ne isotopes we show that this high-resolution mode of resonance detection permits, even in a case of a small isotope effect, unique assignment of bound level sequences compatible with a single gas-surface potential curve.

Journal Article↗

PubMed2006

Consistent expression of HGF and c-met in the perinatal lung.

BACKGROUND: Hepatocyte growth factor (HGF), an epithelial cell mitogen, has been shown to participate in normal lung development and in regeneration after lung injury. In human preterm infants, lower pulmonary HGF has been associated with more severe respiratory disease. OBJECTIVES: We studied the protein expression of HGF and its receptor c-met during the perinatal period in the human lung. METHODS: Immunohistochemistry for HGF and c-met was performed on lung tissues from autopsies of 4 fetuses, 5 preterm infants, 5 term infants, and 4 infants with bronchopulmonary dysplasia. RESULTS: Immunohistochemistry for HGF showed staining in all cases in mesenchymal cells (fibroblasts and cartilage cells). Additional staining was found in bronchial and distal airway epithelium. Immunohistochemistry for c-met showed staining in bronchial and distal airway epithelium, and in most cases in neutrophils. CONCLUSIONS: The consistent expression of HGF and c-met during the perinatal period supports a physiological role for HGF in human lung development.

Abortion, Spontaneous↗

PubMed2006

Gastric electrical stimulation for intractable vomiting in patients with chronic intestinal pseudoobstruction.

Gastric electrical stimulation (GES) is effective for medically refractory nausea and vomiting in patients with idiopathic or diabetic gastroparesis (DGP). We studied whether GES has similar effects in chronic intestinal pseudoobstruction (CIP). Patients referred for chronic small bowel (SB) motor dysfunction requiring parenteral nutrition and having a weekly vomiting frequency (WVF) >/=7 refractory to prokinetics and antiemetics were included. Patients were implanted for high-frequency GES 12 stimuli min(-1), laparoscopy being the first-line implantation procedure. Results were compared with those obtained in 11 DGP patients. Three patients with familial CIP and one patient with postsurgical CIP fulfilled the criteria. Gastric emptying was delayed in two and was normal in two patients. SB transit time was markedly delayed. Laparoscopy was used in three patients, one patient required laparotomy. During GES, WVF decreased from 24 (mean) before GES to 6.9 at 12 months and 7.5 at last visit. Vomiting reduction was 50-90% at last visit. For the DGP patients, WVF decreased from 23 before GES to 3.5 at 12 months and 3.5 (P < 0.01) at last visit. In patients with CIP and medically refractory vomiting, GES seems to have an anti-vomiting effect comparable to that seen in patients with severe DGP. GES should be considered as a therapeutic option for these patients.

Adult↗

PubMed2006

The carcinogenic role of oncogenic HPV and p53 gene mutation in cervical adenocarcinomas.

Thirty tumors were collected from our archive of cervical adenocarcinomas. They were examined with respect to the content of oncogenic HPV and presence of mutations in the p53 gene exons 5 through 8. Furthermore, available clinical information on the cases was reviewed. For the detection of p53 gene and presence of oncogenic HPV, PCR followed by direct sequence analysis of the amplified DNA was employed. Seventeen tumors were identified as HPV-positive, comprising both HPV types 18 and 16. Six cases showed a p53 gene mutation, of which five were of the missence and one of the silent type. No statistical correlation between the occurrence of oncogenic HPV and presence of p53 gene mutation (p = 0.67) was recorded. Among the tumors with p53 gene mutation, three were HPV-positive and three were HPV-negative. The determination of p53 gene mutations was not related to clinical findings such as the stage of the tumor or presence of metastases of the lymph nodes. However, p53 gene mutations were somewhat more prevalent in low differentiated tumors (p < 0.02). The results indicate that oncogenic HPV and p53 gene mutations have independent carcinogenic roles in cervical adenocarcinomas.

Adenocarcinoma↗

PubMed2005

The genetic basis of naturally occurring pollen color dimorphisms in Nigella degenii (Ranunculaceae).

Nigella degenii ssp. barbro and ssp. jenny differ from related taxa in being dimorphic for pollen color, with some plants having dark pollen and others light pollen. In this study we performed experimental crosses to determine whether the difference in pollen color is governed by few or many loci and whether the two subspecies utilize the same gene to control pollen color. Patterns of segregation in crosses between morphs show that dark pollen is dominant over light pollen and that a single major gene is responsible for most of the variation in pollen color. Consequently it should be relatively easy for pollen color dimorphisms to establish and spread in these subspecies. Aberrant segregation ratios were attributed to genetic factors that reduced the expression of the allele conferring dark pollen or processes that sorted between color morphs during seed development. Crosses between dark pollen plants from different subspecies showed signs of complementation in the F2 generation, but the frequency of the light morph was too low to support a model involving complementary action of recessive alleles at two separate loci. Based on this and other observations, we hypothesize that the pollen color difference is controlled by the same major locus in the two subspecies.

Analysis of Variance↗

PubMed2005

Type distribution, viral load and integration status of high-risk human papillomaviruses in pre-stages of cervical cancer (CIN).

A series of 176 archival cervical intraepithelial neoplasia (CIN) was analysed for the presence, viral load and integration status of 'high-risk' types of human papillomavirus (HR-HPV). The samples were assayed using newly developed methods based on real-time PCR. Two methods for the extraction of DNA from the paraffin-embedded biopsies were compared: a protocol based on the MagNA pure system (Roche) and a Qiagen spin column kit (Qiagen). It was possible to amplify 94% (166) of the samples. Of these, 36, 63 and 80% of the CIN I, II and III cases contained HR-HPV. HPV 16 was the most prevalent, and was found in 20, 28 and 46% of the CIN I, II and III cases, respectively. The second most frequent HR-HPV was type 33 group, and in CIN II it was as prevalent as HPV 16. The median number of copies of HR-HPV per cell was not significantly different in the CIN I, II and III cases, but there was a wide range of viral load values over several magnitudes, regardless of the grade of CIN. All samples were found to contain integrated forms of HPV 16, frequently mixed with an episomal form.

DNA, Viral↗

PubMed2005

Antigen-specific beta-chemokine production and CD8 T-cell noncytotoxic antiviral activity in HIV-2-infected individuals.

Human immunodeficiency virus-2 (HIV-2) is less pathogenic than HIV-1, and the disease progression in HIV-2-infected individuals seems to be similar to that seen in HIV-1-infected long-term nonprogressors. Cell-mediated immune responses and the production of noncytotoxic CD8+ T-cell antiviral factors (CAF) and beta-chemokines have been correlated to protection against HIV-1 and associated with asymptomatic infection and slower disease progression. We investigated the antigen-induced beta-chemokine production in HIV-2-infected patients living in Sweden and in Guinea-Bissau. We also compared in vitro CD8+ T-cell-mediated noncytotoxic antiviral activity against beta-chemokine-sensitive R5 virus (HIV-1Bal) and beta-chemokine-insensitive X4 virus (HIV-1IIIB) in HIV-2-infected patients with that in HIV-1-infected patients. HIV-2-specific beta-chemokine production was demonstrated in a majority of the HIV-2-infected subjects. CD8+ T cells of both HIV-1 and HIV-2-infected individuals suppressed R5 virus replication in vitro in a similar manner, while the inhibition of X4 virus replication seemed to be more frequent and of a higher magnitude among HIV-2-infected patients compared to HIV-1-infected subjects. Taken together, our results indicate that the production of CD8+ T-cell noncytotoxic antiviral factors may contribute to the low transmission of the virus and slower disease progression in HIV-2-infected patients.

Adult↗

PubMed2005

Human immunodeficiency virus (HIV)-2-specific T lymphocyte proliferative responses in HIV-2-infected and in HIV-2-exposed but uninfected individuals in Guinea-Bissau.

Human immunodeficiency virus (HIV)-2-specific T lymphocyte proliferative responses were determined in cultures of peripheral blood mononuclear cells from HIV-2-exposed uninfected individuals, HIV-2-infected individuals and HIV-negative controls in Guinea-Bissau. Increased HIV-2-specific T lymphocyte proliferative responses were detected in both groups compared to HIV-negative controls (healthy HIV-uninfected individuals without known exposure to an HIV-infected person); five out of 29 of the HIV-2-exposed uninfected and half (16 of 32) of the HIV-2-infected individuals had stimulation indexes >2, compared to one out of 49 of the HIV-negative controls (P = 0.003 and P < 0.0001, respectively). The exposed uninfected individuals had reactivity to a HIV-2 V3-peptide corresponding to amino acids 311-326 of the envelope glycoprotein, while the HIV-2-infected people reacted mainly to HIV-2 whole viral lysate. Thus, this study demonstrates a high degree of HIV-2-specific T helper cell activity, as measured by lymphocyte proliferation, in HIV-2-exposed uninfected individuals as well as in HIV-2-infected subjects. These immune responses could be important for resistance to the infection and for the control of established infection and, thus, play a role in the lower transmission and progression of HIV-2 compared to HIV-1.

Adolescent↗

PubMed2005

Effect of maternal diabetes on phosphorylation of insulin-like growth factor binding protein-1 in cord serum.

AIMS: The insulin-like growth factor (IGF) system is considered important in the regulation of fetal growth. Binding of IGFs to specific binding proteins (IGFBPs) modifies their actions. In fetal blood, IGFBP-1 is the primary IGF binding protein whose phosphorylation generates proteins with different affinities for IGF-I. We studied cord serum IGFBP-1 phosphoisoform profiles in normal pregnancies and in diabetic pregnancies, which are frequently complicated by macrosomia. RESEARCH DESIGN AND METHODS: Cord serum IGFBP-1 phosphoisoform concentrations were measured at birth by two immunoenzymometric assays in 67 pregnancies complicated by Type 1 diabetes, in 28 pregnancies complicated by insulin-treated gestational diabetes, and in 62 normal pregnancies. RESULTS: Cord serum highly phosphorylated IGFBP-1 (hpIGFBP-1) concentrations were lower in pregnancies complicated by Type 1 diabetes (204 +/- 36 microg/l, P = 0.032) and in pregnancies complicated by gestational diabetes (170 +/- 28 microg/l, P = 0.031) than in controls (316 +/- 34 microg/l). Cord serum lesser phosphorylated IGFBP-1 (lpIGFBP-1) concentrations were similar in diabetic and normal pregnancies (P = 0.692 between groups by analysis of variance). Relative birth weight correlated negatively with cord serum hpIGFBP-1 and lpIGFBP-1 in diabetic pregnancies, and with cord serum lpIGFBP-1 in normal pregnancies. CONCLUSIONS: Maternal diabetes is associated with suppressed hpIGFBP-1 but unaltered lpIGFBP-1 concentrations in cord serum, suggesting that IGFBP-1 phosphoisoforms are differentially regulated in the fetus. Because hpIGFBP-1 has a higher affinity for IGF-I than does lpIGFBP-1, diabetes-related changes in fetal IGFBP-1 phosphorylation may increase IGF-I bioavailability and, consequently, stimulate fetal growth. This may partly explain the increased occurrence of macrosomia in diabetic pregnancies.

Adult↗

PubMed2005

Prevention of dislocation of the hip in children with cerebral palsy. The first ten years of a population-based prevention programme.

In 1994, a register for cerebral palsy and a health-care programme were started in southern Sweden with the aim of preventing dislocation of the hip in children with cerebral palsy. It involved all children with cerebral palsy born in 1992 or later. None of the 206 affected children born between 1992 and 1997 has developed a dislocation following the introduction of the prevention programme. Another 48 children moved into the area and none developed any further dislocation. Of the 251 children with cerebral palsy, aged between five and 11 years, living in the area on January 1, 2003, only two had a dislocated hip. One boy had moved into the area at age of nine with a dislocation and a girl whose parents chose not to participate in the programme developed bilateral dislocation. One boy, whose condition was considered to be too poor for preventative surgery, developed a painful dislocation of the hip at the age of five years and died three years later. Eight of 103 children in a control group, consisting of all children with cerebral palsy living in the area between 1994 and 2002, and born between 1990 and 1991, developed a dislocation of the hip before the age of six years. The decreased incidence of dislocation after the introduction of the prevention programme was significant (p < 0.001). Dislocation of the hip in cerebral palsy remains a serious problem, and prevention is important. Our screening programme and early intervention when lateral displacement of the femoral head was detected appear to be successful.

Cerebral Palsy↗

PubMed2004

Infrared spectroscopy of oxygen adsorbed on hydrogen covered Pt(111).

Using infrared reflection absorption spectroscopy we have investigated how preadsorbed hydrogen affects the adsorption of O(2) on the Pt(111) surface at temperatures below the onset of the water formation reaction. On the fully hydrogen covered surface, Theta(H)=1, O(2) physisorbs at temperatures below 45 K, the weakly dipole active internal stretch vibration is observed at 1548 cm(-1). Unlike on the clean Pt(111) surface, this adsorption state does not act as a precursor for O(2) chemisorption. The physisorbed molecules simply desorb above 45 K and no chemisorbed O(2) state is populated directly from the gas phase in the temperature range 45-90 K. When the surface is approximately half covered, Theta(H) approximately 0.4, with preadsorbed hydrogen, O(2) chemisorbs on the clean Pt(111) surface regions in the characteristic peroxolike and superoxolike states with vibration frequencies around 700 cm(-1) and 870 cm(-1). These values correspond to dense O(2) islands which develop already at low O(2) coverages. At this hydrogen coverage, we find that the initial sticking probability of chemisorbed O(2) is drastically reduced at 90 K and the general uptake also proceeds slowly when compared with observations for the clean surface. We suggest that this is due to a change in the behavior of the physisorbed O(2) precursor.

Journal Article↗