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S Wall

Publications and source records attributed to S Wall.

At least 109 records · Page 6Linked to original sources
PubMed1993

Identification of spheroplast-like agents isolated from tissues of patients with Crohn's disease and control tissues by polymerase chain reaction.

Mycobacterium paratuberculosis has been isolated from tissue taken from patients with Crohn's disease and has been implicated in the etiology of this disease. On culture, the organisms appear initially as cell wall-deficient, spheroplast-like forms that are difficult to identify by conventional techniques. Here we examine 30 unidentified cultures by the polymerase chain reaction using primers specific for M. paratuberculosis, Mycobacterium tuberculosis, and Mycobacterium avium restriction fragment length polymorphism type A/I and also by a non-species-specific mycobacterial polymerase chain reaction. Six of these cultures, all from Crohn's disease, were shown to contain DNA from M. paratuberculosis. Cultures from both Crohn's disease and controls were found to contain mycobacterial DNA of unknown specific origin.

Base Sequence↗
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

Diesel exhaust exposure and smoking: a case-referent study of lung cancer among Swedish dock workers.

We studied 50 lung cancer cases and 154 matched referents, all dock workers, for whom we obtained smoking information and employment histories. We assessed exposures from information on annual diesel fuel consumption from each of the 15 ports included. We used a smoker/nonsmoker term and three exposure variables (machine time, cumulative fuel, and exposed time with fuel consumption above a minimum cutpoint) in the analyses, with three categories for each exposure variable. Odds ratios (ORs) for medium and high exposure groups are consistently higher than reference (low), with an increasing exposure-response trend that is most marked for the exposed time variable (ORs: low = 1.0; medium = 1.6; high = 2.8). When smoking and that exposure variable are simultaneously included in the analyses, odds ratios for the medium (OR = 2.7) and high (OR = 6.8) levels of exposure increase, as does the odds ratio for smoking. Separating smokers and nonsmokers, with the low exposed nonsmokers as the common reference category, the odds ratios are 1.6 (medium) and 2.9 (high) for the nonsmokers, and 10.7 (medium) and 28.9 (high) for smokers. These results indicate an independent effect of diesel exhaust exposure and a strong interaction between smoking and diesel exhaust.

Humans↗
PubMed1993

Air pollution levels, meteorological conditions and asthma symptoms.

We wanted to assess relations between the daily occurrence of asthma symptoms and fluctuations of air pollution concentrations and meteorological conditions. In a panel of 31 asthmatic patients residing in the town of Piteå in northern Sweden, severe symptoms of shortness of breath, wheeze, cough and phlegm were recorded in an asthma diary together with suspected causes. Sulphur dioxide, nitrogen dioxide, black smoke, relative humidity and temperature were used to evaluate the relationship to the environment. By using multivariate analyses, we found that daily variations in the particulate pollution levels, indicated by black smoke levels below the criteria limits, had significant effects on the risk of developing severe symptoms of shortness of breath. This association was stronger among 10 subjects, who had at least five incident days with severe shortness of breath. Meteorological conditions were not significant in the multivariate models. Cough and phlegm did not show significant relationships to any environmental condition that was evaluated. Only one-third of the subjects reported, at least once during the study, symptoms believed to be related to air pollutants, although we found significant correlations between the pollution levels and the frequency of pollution-related symptoms. We conclude that an association has been established for black smoke as pollutant and shortness of breath as respiratory symptom, and that in certain asthmatics, effects were occurring at lower particulate levels than suggested previously.

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↗
PubMed1993

Evidence for heterogeneity in facioscapulohumeral muscular dystrophy (FSHD).

Facioscapulohumeral muscular dystrophy (FSHD) is a slowly progressive primary disease of muscle which is usually inherited as an autosomal dominant disorder. FSHD has been localized to the long arm of chromosome 4, specifically to the 4q3.5-qter region. Initially published linkage studies showed no evidence for heterogeneity in FSHD. In the present study we have examined individuals in seven FSHD families. Two-point lod scores show significant evidence for linkage for D4S163 (lod score 3.04 at recombination fraction .21) and D4S139 (lod score 3.84 at recombination fraction .20). D4S171 also gave a positive score (lod score 2.56 at recombination fraction .24). Significant evidence for heterogeneity was found for each of the three markers. Multipoint linkage analysis in this region resulted in a peak multipoint lod score of 6.47. The multipoint analysis supported the two-point studies with odds of 20:1 showing linkage and heterogeneity over linkage and homogeneity. Five of the seven families gave a posterior probability of > 95% of being of the linked type, while two families appeared unlinked to this region of 4q (P < .01%). Individuals in the two unlinked families met the clinical criteria for the diagnosis of FSHD, including facial weakness, clavicular flattening, scapula winging, proximal muscle weakness, and myopathic changes on muscle biopsies without inflammatory or mitochondrial pathology. This study demonstrates genetic heterogeneity in FSHD and has important implications for both genetic counseling and the elucidation of the etiology of FSHD.

Chi-Square Distribution↗
PubMed1992

Secular trends of twinning rate in Sweden.

The change in parity and maternal age in Sweden accounts for the decline in the twinning rate from the 19th century to the middle of the 20th century. The later decline in twinning rate cannot be explained by changes in maternal age and parity. Fecundity appears to be higher in mothers of twins than in other mothers.

Adolescent↗
PubMed1992

Linkage of an important gene locus for tuberous sclerosis to a chromosome 16 marker for polycystic kidney disease.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder of unknown aetiology that affects numerous body systems including skin, brain and kidneys. Some TSC has been linked to chromosome 9, additional TSC genes on chromosomes 11 and 12 have been proposed, but the majority of TSC families remain unlinked. Using TSC families in which data had excluded linkage to chromosome 9, we failed to detect linkage with loci on chromosomes 11, 12 and others. One marker examined was D16S283, the closest locus on the proximal side of the polycystic kidney disease type 1 (PKD1) gene. Linkage between TSC and D16S283 demonstrated a lod score of 9.50 at theta = 0.02 with one family independently presenting a lod score of 4.44 at theta = 0.05. These data reveal an important TSC locus near the region of PKD1 on chromosome 16p13.

Alleles↗
PubMed1992

Risk of developing insulin-dependent diabetes mellitus (IDDM) before 35 years of age: indications of climatological determinants for age at onset.

This study analyses data from two nationwide prospective diabetes registries now covering about 3400 cases from 19 million person-years of follow-up in the age group 0-34 years. The risk of developing insulin-dependent diabetes mellitus (IDDM) per 100,000 individuals before 15 years was 386 (95% confidence intervals (CI): 362-410) for boys and 391 (95% CI: 367-415) for girls and by 35 years 701 (95% CI: 671-731) for men and 562 (95% CI: 534-690) for women. The incidence rate showed a maximum for both boys and girls in early puberty. After pubertal years a sharp increase in the male to female incidence ratio of IDDM was notable. At 10-14 years it was 0.94, at 15-19 years 1.59 and at 20-24 years 2.08. A Cox regression model was used to analyse the effects on age at onset of sex, population density and climatological factors as measured by north-south area of residence and season at onset. The effect of sex was confirmed (P less than 0.001). A significant effect (P = 0.004) of season was shown when the four seasons were classified according to a four stage scale related to mean temperature. When dividing Sweden into 11 regions according to north-south gradient (Latitude 55 degrees, 56 degrees, 57 degrees, ..., 65 degrees) a significant effect (P = 0.038) was also found. However, no effects of population density or living near the coast versus in the interior were found. It is concluded that a large proportion of the young are at risk of developing this chronic disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Mortality of all incident cases of diabetes mellitus in Sweden diagnosed 1983-1987 at age 15-34 years. Diabetes Incidence Study in Sweden (DISS) Group.

From 1983 all incident cases of diabetes in the age group 15-34 years in Sweden have been recorded prospectively. The aim of the present study was to assess the mortality pattern of cases reported for 1983-87 and followed until the end of 1987. Eighteen deaths were identified by linkage to the national death register. When comparing the mortality in the cohort with Swedish males and females in general, an excess mortality was found in all the groups studied. It is, however, less pronounced if the analysis is restricted to those with Type 1 diabetes (standardized mortality ratio (SMR) and 95% confidence interval = 2.1; 0.8, 4.6), Type 2 diabetes (SMR = 4.8; 1.3, 12.3) or Type 1 + Type 2 (SMR = 2.7; 1.3, 5.0). Eight (44%) of the deaths were in patients with secondary diabetes, a diagnosis that applied to less than 3% of the cohort. Alcohol abuse was prevalent in six cases and suspected in another two. Hypoglycaemia was established as a cause of death in only one case but could not be excluded in a further six. Only one death was associated with ketoacidosis. No valid support for an increased risk of the 'dead in bed' syndrome was found. We suggest that diabetes was decisively important for the death in two cases and less important in 10. In the remaining six cases the existing documentation precludes a proper judgement.

Adolescent↗
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

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

IS900-promoted stable integration of a foreign gene into mycobacteria.

An artificial mycobacterial transposon was constructed by placing two copies of the insertion sequence IS900 flanking a kanamycin resistance gene into a non-(mycobacterial) replicating vector. Constructs were introduced into mycobacteria by electroporation and transposition events conferring kanamycin resistance were selected. Integration of IS900 into several genomic sites was analysed by Southern blotting and shown to involve both simple insertions and cointegrate formation, suggesting that IS900 can transpose by a replicative mechanism. Kanamycin resistance of IS900-integrated transformants was shown to be stable in the absence of selection.

Blotting, Southern↗
PubMed1991

IS901, a new member of a widespread class of atypical insertion sequences, is associated with pathogenicity in Mycobacterium avium.

An insertion sequence (IS901), found in pathogenic strains of Mycobacterium avium, but absent in M. avium complex isolates from patients with acquired immune deficiency syndrome (AIDS), has been isolated and sequenced. This insertion element has a nucleotide sequence of 1472 bp, with one open reading frame (ORF1), which codes for a protein of 401 amino acids. The amino acid sequence, terminal ends and target site of IS901 are similar to those of IS900, present in Mycobacterium paratuberculosis. However, the DNA sequences of these two IS elements exhibit only 60% homology, compared to a DNA homology of 98% between their respective hosts. IS901, like IS900, appears to belong to a family of related insertion elements present in actinomycetes and other bacteria. M. avium strains containing IS901 were found to be more virulent in mice than closely related strains lacking IS901. IS901 may be a useful tool for the study of the genetics of virulence in the M. avium complex and for obtaining stable integration of foreign genes into mycobacteria.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Reproductive mortality and its relation to different methods of birth control.

This report evaluates the decrease in maternal mortality and its relation to family planning methods in Sweden during the years 1911-80. In the 1930s fertility was low but illegal abortions were at a high level and the associated maternal death rate was 18.5 per 1000 women. With the legalization of abortion and the introduction of modern contraceptive methods, the crude reproductive mortality rate in 1965-70 was 1.7 per 100,000 women and this was reduced still further, especially for younger women, by the late 1970s. Standardized reproductive mortality was then 80% higher than the crude rate, indicating the importance of modern family planning methods. Mortality associated with oral contraceptive or IUD use in Sweden during the 1960s and 1970s was lower than in England and the US. Mortality associated with sterilization was 6.2 per 100,000 procedures.

Abortion, Induced↗
PubMed1990

The Swedish childhood diabetes study. An analysis of the temporal variation in diabetes incidence 1978-1987.

The Swedish Childhood Diabetes Register combines continuous prospective reporting on incident cases and regular retrospective review of hospital records in all paediatric departments in the country and has, from 1978 to 1987, compiled 3838 cases. A validity test using an independent source has revealed a degree of ascertainment of 100%. When fitting a linear regression model to the natural logarithm of the yearly incidence rates, a significant increase over time was found for girls and for both sexes combined. To analyse the time trend with respect to age, sex, calendar year and birth cohort and their interactions, Poisson regression modelling was used. There was a significant age effect and interaction between age and sex. When these age and sex effects were taken into account a significant increase over time was found. Calendar period had a significant effect when adjusted for cohort effects whereas cohort did not add significantly to the explanation of the variance. There was no significant interaction between sex and calendar period indicating similar time variations for both sexes. The temporal variability was also apparently similar among different age groups. The observed increase of childhood insulin-dependent diabetes mellitus (IDDM) affecting both sexes and all age groups, strongly supports the importance of environmental factors in the aetiology of IDDM.

Adolescent↗