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Biomedical subjects

A Sandström

Publications and source records attributed to A Sandström.

At least 37 records · Page 2Linked to original sources
PubMed1996

Cancer incidence for children born in a smelting community.

The Rönnskär smelter in Skellefteå, Sweden, produces significant environmental pollutants, such as lead, arsenic, copper, cadmium and sulphur dioxide. The purpose of the present study was to determine whether children born to women living near the smelter during pregnancy had an increased risk of childhood cancer. The study group consisted of children born between 1961 and 1990 in the municipality of Skellefteå and parish of Holmsund. Through linkage to the Swedish Cancer Registry cancer diagnoses in the study group were obtained and compared with the expected ones based on the national incidence rates. Thirteen cases of childhood cancer were identified among children born in the vicinity of the smelter against 6.7 expected (SIR 195, 95%CI 88-300). Among distant born the observed number of cases (n = 42) was similar to that expected (n = 41.8).

Adolescent↗
PubMed1995

A one-year community study of under-fives in rural Ethiopia: patterns of morbidity and public health risk factors.

A prospective weekly home surveillance study was undertaken to determine morbidity patterns within the Butajira Rural Health project in central Ethiopia. Overall prevalence of illness was 5.8% in 1216 person-years observed among rural Ethiopian children aged under 5 years. Acute respiratory infections (ARI) (prevalence 2.8%) and acute diarrhoea (2.4%) were the commonest conditions. Episodes of illness were distributed unequally among children, with a mean of 2.34 episodes per child. These included an average of 1.13 episodes of ARI (of which 0.16 had lower respiratory symptoms [ALRI]) and 1.17 episodes of acute diarrhoea. Sanitation factors were the principal risks for gastroenteritis, while living in rural areas predisposed children to ARI. Parental factors such as illiteracy were also linked to morbidity.

Acute Disease↗
PubMed1995

Lung cancer, smoking and smelter work in a occupational cohort.

BACKGROUND: A cohort of employees at a smelter in Northern Sweden has been updated with the addition of information regarding smoking habits to evaluate the role of smoking in the occurrence of lung cancer in various job categories and employment cohorts. An updated analysis of earlier studies of the interaction between roaster work and smoking is also reported. The cohort members first employed during the period 1928-1979 have been followed up to 1 January 1988. Information regarding smoking habits for 69% of the cohort was gathered in a questionnaire study. RESULTS: The prevalence of daily smoking decreased during the study period and was lower for salaried employees. The figures were, however, comparable with national figures for similar social and occupational strata. Adjustment for smoking did not alter the lung cancer gradient between employment cohorts or between job categories. CONCLUSIONS: The interaction between smoking and roaster work was confirmed and the benefits from ceasing to smoke shown to be greater among the roaster workers.

Adult↗
PubMed1994

The solution structure of a 3'-phenazinium (Pzn) tethered DNA-RNA duplex with a dangling adenosine: r(5'G-AUUGAA3'):d(5'TCAATC3'-Pzn).

The 3'-Pzn group tethered to an oligo-DNA stabilizes a DNA-RNA hybrid duplex structure by 13 degrees C compared to the natural counterpart. This report constitutes the first full study of the conformational features of a hybrid DNA-RNA duplex, which has been possible because of the unique stabilization of this rather small duplex by the tethered 3'-Pzn moiety (Tm approximately 40 degrees C from NMR). In this study, a total of 252 inter- and intra-strand torsional and distance constraints along with the full NOE relaxation matrix, taking into account the exchange process of imino and amino protons with water, have been used. The 3'-Pzn-promoted stabilization of the DNA-RNA hybrid duplex results in detailed local conformational characteristics such as the torsion angles of the backbone and sugar moieties that are close to the features of the other natural DNA-RNA hybrids (i.e. sugars of the RNA strand are 3'-endo, but the sugars of the DNA strand are intermediate between A- and B-forms of DNA, 72 degrees < P < 180 degrees; note however, that the sugars of our DNA strand have a C1-exo conformation: 131 degrees < P < 154 degrees). This study suggests that 3'-Pzn-tethered smaller oligo-DNA should serve the same purpose as a larger oligo-DNA as a antisense inhibitor of the viral mRNA. Additionally, these types of tethered oligos have been found to be relatively more resistant to the cellular nuclease. Moreover, they are taken up quite readily through the cellular membrane (14) compared to the natural counterparts.

Hydrogen Bonding↗
PubMed1994

Socio-geographical patterns of HIV-1 transmission in Kagera Region, Tanzania.

A population-based study on the prevalence of HIV-1 infection in the Kagera region was performed in 1987. The study was based on a multistage cluster sampling technique covering the age-group 15-54 years. The study showed considerable variation of prevalence of HIV-1 infection in the areas studied. A total of 2475 adults were studied and the overall prevalence of HIV-1 infection in the region was 9.6% with a higher prevalence in the urban area (24.2%) compared to that in the rural areas (4.9%). In the present analysis, information on individuals collected during the prevalence study has been used to characterize smaller geographical areas of several villages (wards) and to form the basis for an aggregated analysis of geographical and social patterns relevant to HIV-1 transmission in the studied areas of the region. Kagera region is a heterogeneous society with respect to, for example, religion, ethnic groups and family patterns. There was a moderately strong positive correlation between HIV-1 prevalence and frequent change of sexual partners on the ward level. In Bukoba town the prevalence varied remarkably among the wards, with the lowest prevalence in the ward having the highest social status. In the rural areas, however, the prevalence in the wards decreased considerably with increasing distance from Bukoba town. This aggregated analysis of socio-geographical patterns of HIV-1 transmission characteristics has provided us with information for prioritizing areas of HIV/AIDS intervention in the Kagera community.

Adolescent↗
PubMed1994

The Butajira Rural Health Project in Ethiopia: a nested case-referent (control) study of under-5 mortality and its health and behavioural determinants.

The associations between under-5 mortality and its health and behavioural determinants were investigated in a rural district of Ethiopia, by means of a concurrent case-referent technique nested within a study-base population established in 1987. Three-hundred and six infant and child deaths registered over a period of 1 year, were contrasted with 612 controls, matched for age, sex and study area. Data were collected by trained non-medical workers using a structured questionnaire. Breastfeeding and supplementary feeding came out as strongly protective against under-5 mortality, even when controlling for parental and environmental determinants. Early termination of breastfeeding was demonstrated to have a substantial impact on mortality, particularly on that caused by diarrhoea. Late introduction of supplementary feeding, particularly of protein origin, was also associated with increased under-5 mortality. When the relative impacts of parental, environmental and behavioural determinants are compared, the greater impact of parental factors can be demonstrated, especially among infants.

Age Factors↗
PubMed1994

Maternal mortality in Sweden, 1980-1988.

OBJECTIVE: To assess recent maternal mortality in Sweden according to the different definitions of the eighth, ninth, and tenth editions of the International Classification of Diseases (ICD). METHODS: All maternal deaths in Sweden during 1980-1988 were sought in the Medical Birth Registry and in the Registers of Births and Deaths. Hospital records and autopsy reports were requisitioned. RESULTS: According to ICD-9, the maternal mortality ratio in Sweden for 1980-1988 was 7.4 per 100,000 live births. Of the 58 deaths, 36 were direct maternal deaths. Embolism, hemorrhage, preeclampsia, and infection were the predominant causes in the direct cases. Advanced age was the most pronounced risk factor. Suboptimal standard of care was a contributing cause in almost one-third of the direct maternal deaths. Accidental or incidental deaths, including suicide, accidents, and pregnancy-related deaths, added six cases. There were 76 late maternal deaths, occurring 43-365 days postpartum. Malignancy, stroke, and heart disease were the predominant causes. After malignant disease, suicide constituted the leading cause of pregnancy-related deaths within 1 year of delivery. CONCLUSIONS: Regular reviews of maternal mortality are still important in a country with a low rate of maternal deaths. The new classification of maternal deaths allows a better international comparison of mortality risks. Continuous surveillance of maternal deaths and pregnancy-related deaths requires record linkage of birth and death registrations.

Adult↗
PubMed1993

Solution structure of lariat RNA by 500 MHz NMR spectroscopy and molecular dynamics studies in water.

A 500 MHz NMR study of the lariat RNA tetramer 1 and pentamer 2 mimicking the naturally occurring lariat RNA is reported. The conformational properties of 1 and 2 were compared with those of a linear branched RNA tetramer 3, which show that the conformational features of the two lariat RNAs, 1 and 2, are quite constrained and significantly different from those observed for the linear branched RNA tetramer 3. The conformation of all sugar residues forming the lariat ring in 1 and 2 are locked in a rigid South-type conformation. All residues in both lariat RNAs have a high population of gamma+ (67-85%) and beta t (95-100%) rotamers except guanosine where the gamma+ population is low. The conformation around the glycosidic bond is anti for all residues except for guanosine where NOE data indicates an equilibrium of syn<-->anti. In both lariat RNAs, 1 and 2, the temperature dependent 1H and 31P chemical shifts as well as the oligomerization shifts, with respect to adenosine 2',3',5'-triethyl-phosphate (Sund et al., 1992, Tetrahedron 48, 695) suggests that the 3'-->5' linked U4 or C4 residue is stacked on guanosine. Subsequently, 1H-1H, 1H-31P and 13C-31P coupling constants derived torsional constraints were used for molecular dynamics study in water with counter sodium ions for a total of 226 ps. The MD simulations were first carried out with harmonic torsional constraints which were derived from J couplings (0-86 ps) and then completely without constraints (96-226 ps). The lack of any major changes in the conformation of the two lariat-RNA structures upon releasing the NMR constraints indicate that the conformers generated in the MD simulation in water agree well with the structural features suggested by experimental observables. This means that the ensemble of conformers generated during the MD trajectory of 226 ps are not artificially held in these conformations due to the NMR constraints, suggesting that these conformers can be considered to be good representatives of the actual NMR observed solution structures.

Base Sequence↗
PubMed1993

Structural studies of the 5'-phenazinium-tethered matched and G-A-mismatched DNA duplexes by NMR spectroscopy.

The mechanism through which modified oligo-DNA analogues act as antisense repressors at the transcriptional and translational level of gene expression is based on the information content in the nucleotide sequence which is determined by the specific base pairing. The efficiency of such action is largely determined by the stability of the duplex formed between the oligonucleotide reagent and the target sequence and also by the mismatched base pairing, such as G-A, that occurs during replication or recombination. We herein report that the phenazinium (Pzn)-tethered matched duplex p(d(TGTTTGGC)):(Pzn)-p(d(CCAAACA)) (III) (Tm = 50 degrees C) has a much larger stability than the parent matched duplex p(d(TGTTTGGC)):p(d(CCAAACA)) (I) (Tm = 30 degrees C). On the other hand, the Pzn-tethered G-A-mismatched duplex p(d(TGTTTGGC)):(Pzn)-p(d(ACAAACA)) (IV) (Tm = 34 degrees C) is only slightly more stable than its parent mismatched duplex p(d(TGTTTGGC)):p(d(ACAAACA)) (Tm = 25 degrees C). A detailed 500 MHz NMR study and constrained MD refinements of NMR-derived structures have been undertaken for the DNA duplexes (I), (II), (III) and (IV) in order to understand the structural basis of stabilization of Pzn-tethered matched DNA duplex (delta Tm = 20 degrees C) compared to mismatched duplex (delta Tm = 9 degrees C). Assignment of the 1H-NMR (500 MHz) spectra of the duplexes has been carried out by 2D NOESY, HOHAHA and DQF-COSY experiments. The torsion angles have been extracted from the J-coupling constants obtained by simulation of most of the DQF-COSY cross-peaks using program SMART. The solution structure of the duplexes were assessed by an iterative hybride relaxation matrix method (MORASS) combined with NOESY distances and torsion angles restrained molecular dynamics (MD) using program Amber 4.0. The standard Amber 4.0 force-field parameters were used for the oligonucleotide in conjunction with the new parameters for Pzn residue which was obtained by full geometry optimization using ab initio program (3-21G basis set). It has been shown that mismatched G-A bases are in the anti-anti conformation. The mismatched 7G-1A form stable base pairs through inter-strand hydrogen bonds (N7(A)...HN2(G) (1.92 A) with a subtended angle of 176 degrees and N3(G)...HN6(A) (2.01 A) with a subtended angle of 153 degrees (the 'amino-type' hydrogen bond)) and a propeller twist of 36 degrees for 7G-1A residues.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenine↗
PubMed1993

AIDS epidemic in Kagera region, Tanzania--the experiences of local people.

This study is part of a collaborative study of HIV infection and AIDS which was launched in 1987 in the Kagera region, Tanzania. This region is characterized as one of the areas most affected by the AIDS epidemic. In order to describe and analyse the epidemiology of HIV infection in the area and also to contribute to the intervention process, a long-term population-based project was initiated. The study was launched in January 1989 as an in-depth behavioural study to describe the experiences of the local people of the AIDS epidemic in the region. The specific objectives were to determine the people's attitudes, perceptions, responses and norms relevant to AIDS-related problems. The data were collected through tape recorded interviews, focus group discussions and direct observations of risk behaviour. The interviews were conducted in 10 villages, in urban and rural Bukoba as well as in Muleba districts. In each village five households were selected and visited once a week for about 6 months. The focus group discussions were held mainly with young males, females, married women and married men, elders and religious leaders, government and party leaders, and other key informants. Perceptions, attitudes and patterns of behaviour among the local people are described in the context of the HIV transmission in the area. The descriptions give answers to questions like: How do people perceive and interpret AIDS? How do they react to AIDS? How do they judge causes and risks? What are the attitudes to people with AIDS and those suspected to have AIDS? What are the implications of these values in affected communities?

Acquired Immunodeficiency Syndrome↗
PubMed1993

Cancer incidence among male salaried employees at a smeltery in northern Sweden.

This study focuses on mortality and cancer incidence among the male salaried employees at a copper smeltery in northern Sweden, where previously an increased lung cancer risk had been demonstrated among blue-collar workers, with all likelihood due to arsenic exposure. During the period 1928-1979 there has been 1,255 male salaried employees and 6,334 male blue-collar workers. Three cohorts were formed; those who had worked only as salaried employees, those who had worked only as blue-collar workers and those had worked in both job categories. The mortality among the entire group of salaried employees was comparatively lower than that of Sweden as a whole. The incidence of lung cancer was highest among those who had worked in both job categories, most of them former blue-collar workers. The trends in lung cancer incidence among the blue-collar workers along and among those who had had both types of jobs showed the same pattern, with a peak in the 1970s. The decrease in this trend started earlier among the salaried employees. When job category and employment cohort were analyzed together the highest risk was confirmed for those having been employed in both job categories.

Adolescent↗
PubMed1993

The Butajira project in Ethiopia: a nested case-referent study of under-five mortality and its public health determinants.

During one year of follow-up, 306 deaths of children under the age of 5 years were included in a concurrent case-referent study that was based on a population estimated at 28,780 in 1987. A total of 612 live referents, matched for age, sex and study area, were also selected from the study population through density sampling. Data were collected by lay reporters by verbal autopsy. For the study period the estimated cumulative under-five mortality rate was 293 and the infant (0-11 months old) mortality rate was 136 per 1000. Major probable causes of death were diarrhoeal disease or acute respiratory infections (ARI). The relative importance of parental and environmental characteristics was assessed using conditional multiple logistic regression analysis. Under-five mortality was associated with paternal illiteracy, maternal ethnicity, and not being in the committee of people's organizations. Parental factors affected the infants relatively more than they did the children, especially with regard to ARI mortality. This was also noted with "absence of window", a proxy measure for evaluating the type of housing. In terms of etiological fractions a greater number of under-five deaths could be ascribed to parental than environmental conditions, with relatively more infants being affected than children.

Case-Control Studies↗
PubMed1992

Reproductive patterns among Swedish women born 1936-1960.

An analysis was made of a cross-sectional survey of 4,299 women born in Sweden in the period 1936-1960, regarding their reproductive performance. Fecundability was only 12% lower for women in the 30-39 year age interval than for women up to 29 years of age. Cumulative pregnancy rates for individual years fell in the range 93-96%. No difference in fecundability could be discerned between women born in 1936-45 vis-à-vis 1946-60. Primary and secondary infertility were noted for 6.6% and 11.0% respectively of the entire population surveyed. Primary infertility, more prevalent among those born in 1946-60, was found to be related to a higher level of education, an urban life style and low age at first coitus. The risk of suffering a spontaneous abortion increased with advancing maternal age.

Adult↗
PubMed1992

The Butajira rural health project in Ethiopia: epidemiological surveillance for research and intervention in primary health care.

Ten study populations sampled from a total of 86 communities in a rural Ethiopian area, have been registered and followed for a period of four years. A baseline census revealed a median age of 15 years, a literacy rate of 24%, poor housing and environmental conditions, and low utilization of the existing health care facilities. A surveillance system was established which made it possible to estimate the occurrence of vital events. This showed a crude birth rate of 40.3/1000, a crude death rate of 16.4/1000, a life-expectancy at birth of 48 years, an infant mortality rate of 114/1000, a yearly child (1-4 years) mortality rate of 36/1000, and an under-five mortality rate of 210/1000. The implications of these data in terms of the planning and operations of research and health services are discussed, and on-going and projected studies are outlined emphasizing the methodological potentials of this epidemiological study base.

Adolescent↗
PubMed1991

Electronic energy transfer and fluorescence quenching in the active sites of mercuric reductase.

The FAD-containing enzyme mercuric reductase has been studied by means of steady-state and time-resolved fluorescence spectroscopy. The fluorescence relaxation of the excited state of the isoalloxazine ring of FAD can be described by a sum of two exponential functions. The two lifetimes are not due to a different lifetime of each of the two FAD molecules of mercuric reductase. The FAD molecules are quenched dynamically by a quencher that is not sensitive to the solvent viscosity. In vitro activation induces a dynamic quenching of fluorescence, while upon binding of NADP+ the FAD molecules are both statically and dynamically quenched. Time-resolved fluorescence anisotropy experiments of mercuric reductase in water show that the isoalloxazine ring probably undergoes a rapid and restricted vibrational motion of small amplitude. Electronic energy transfer occurs between the two FAD molecules at a rate of about 3.4 x 10(7) s-1. The angle between the emission transition dipole of the donor and the absorption transition dipole of the acceptor is 137 +/- 2 degrees (or 43 +/- 2 degrees). From previous X-ray data of glutathione reductase we find that the corresponding angle is 160 degrees. This suggests that the isoalloxazine rings of mercuric reductase and glutathione reductase are mutually tilted in slightly different ways.

Binding Sites↗
PubMed1991

The Butajira rural health project in Ethiopia: mortality pattern of the under fives.

A total of 492 deaths of children below 5 years of age were registered during a 2-year period of demographic surveillance in a rural population of Ethiopia, where an epidemiologic study base population of 28,780 individuals was established in 1987. Data were collected by lay-reporters using a verbal autopsy method. The under-five cumulative mortality rate was 209 per 1000 children. When sub-divided into infants and children 1-4 years, the respective yearly mortality rates were 101 and 32.3 per 1000. There were considerable variations within the district by Peasants' Associations. Rural Lowlands experienced the highest mortality rates, especially for children 1-4 years. Mortality trends over a 2-year period indicate a significant increase for the child population, but not for infants. Similar trends were observed for boys and girls although the rates for boys were generally higher especially during infancy. More deaths occurred in the months of April, June, and July, and October and November indicating two peak seasons in both years. More deaths occurred in Peasant's Associations that were furthest from the health centre. Major probable causes of death were acute respiratory infections, measles, and diarrhoea. It is concluded that even in rural areas of a developing country it is possible to collect from mothers the much needed and valid fertility and mortality data through epidemiological surveillance by using lay-reporters.

Age Factors↗
PubMed1991

Prevalence of HIV-1 infection and symptomatology of AIDS in severely malnourished children in Dar Es Salaam, Tanzania.

In Dar es Salaam, Tanzania, 200 children with severe malnutrition and controls matched for age, sex, and area of residence were screened for serological evidence of infection with the human immunodeficiency virus type 1 (HIV-1) over 5 months in 1988. The prevalence of HIV-1 antibodies in the malnourished group was 25.5% (51 of 200) compared with 1.5% (three of 200) in the controls. The seroprevalence rate was equally high in malnourished children above the age of 18 months (26 of 102; 25.5%), as in those below this age (25 of 98; 25.5%). The prevalence rate was higher in children with marasmus (38.2%) as compared to children with marasmic-kwashiorkor (12.3%) or kwashiorkor (12.2%). The prevalence of clinical features known to be associated with AIDS was higher in the HIV seropositive malnourished children as compared to the seronegative children. The modified World Health Organization clinical case definition of AIDS in children was also evaluated and found to have a low sensitivity and positive predictive value (62.8 and 57.1%, respectively) but a fairly high specificity (83.9%). It is recommended to routinely rule out HIV infection in malnourished children, especially those with marasmus.

Acquired Immunodeficiency Syndrome↗