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Biomedical subjects

A Ericson

Publications and source records attributed to A Ericson.

At least 55 records · Page 3Linked to original sources
PubMed1988

Environmental factors in the etiology of neural tube defects: a negative study.

A case-control study was made on women who had an infant with a neural tube defect and twice as many controls. Cases and controls were selected from a national medical birth registry from which prospectively collected data on previous pregnancy, contraceptive use, and smoking were also retrieved. Women's occupation was either retrieved from that registry or from census information which was partially checked with direct interview. Information on environmental characteristics of the place of living of the women in early pregnancy was given by field workers who were unaware of the status of case or control. Cases and controls showed no statistically significant difference with regard to previous pregnancies and use of contraceptives at or the month before the time of conception. Case women smoked 10 cigarettes or more a day slightly more often than control women did but the difference was not statistically significant. No statistically significant difference in occupation distribution was seen between cases and controls (but cases had slightly more occupations where chemical exposure is likely), and no differences in home environment could be found. It is concluded that the factors studied play no major etiological role for the origin of neural tube defects in Sweden.

Abnormalities, Drug-Induced↗
PubMed1987

Monitoring of congenital cardiac defects.

An effort was made to identify all infants born with a congenital cardiac defect in 1981 in Sweden by using four different registries: the Swedish Registry of Congenital Malformations, the Medical Birth Registry, the Registry of Death Certificates, and a specially designed Child Cardiology Registry. All infants diagnosed before the age of one year at one of the five child cardiology clinics in Sweden were reported to the latter registry. This registry, together with the Congenital Malformation Registry, can be used for surveillance as they together cover 85%-90% of all severe cases identified. The data quality in the Medical Birth Registry is too low to permit meaningful surveillance. A total of 853 infants with a diagnosis of a congenital cardiac defect were identified. This represents 9 per 1000 newborns. Many of the cases were dubious, but the diagnosis was stated as probable in 708 (7.6 per 1000); 146 infants died. Cardiac diagnoses were stored in the Child Cardiology Registry and in the Registry of Congenital Malformations as ISC codes. A Monitor Code is described that can be used for grouping and monitoring of diagnoses. Using these codes, data in the Child Cardiology Registry for 1981-1983 were analyzed and epidemiologic information on maternal age and parity, sex rate, and birth weight distribution is given.

Death Certificates↗
PubMed1987

Studies on the mechanism of human red cell loss of viability during storage at +4 degrees C in vitro. III. Effects of mixing during storage.

Red cells supended in saline-adenine-glucose-mannitol solution were stored for 42 days at +4 degrees C. One portion was packed by centrifugation and stored unmixed; the other portion was mixed once a week. Red cell fluidity and adenine nucleotide concentration were significantly lower in unmixed than in mixed units and also differed within the packed layer, showing a decrease towards the bottom. Hemolysis was 2.5-fold and microvesiculation 5-fold higher in cells stored unmixed. It is suggested that, during liquid storage, an early accumulation of acid metabolites in the bottom part of packed red cells may play an important role both for adenylate loss and microvesiculation, but lack of membrane-stabilizing action of diethylhexylphthalate may in part explain the latter. Both of these two changes are factors associated with impaired red cell viability. Mixing appears essential to optimize storage conditions for red cells.

Adenine Nucleotides↗
PubMed1987

Maternal occupation and delivery outcome: a study using central registry data.

The outcome of all deliveries in Sweden in 1981 has been studied. The occupation of each mother was obtained by record linkage using census data from November 1980. Rates of perinatal deaths or congenital malformations did not vary according to maternal occupation, more than might be expected to happen by chance, which indicated that maternal occupation is not a major factor in the outcome of these deliveries. There was variation in the rates of low birth weight infants, according to maternal occupation, which may have been an effect of socioeconomic factors associated with the occupation. Within occupational groups, working situations may exist which entail an increased teratogenic risk, but in order to reveal such risks, studies with a different design must be carried out.

Congenital Abnormalities↗
PubMed1987

Birth weight distribution as an indicator of environmental effects on fetal development.

A medical birth registry was used for a geographical analysis of birth weight distribution. Nearly 900,000 Swedish singleton births, 1973-1981, were used for an analysis of the effect of some variables and for standardization for these variables. A marked change in the rate of low birth weight infants (LBW, less than 2,500 g) was seen in the country between 1976 and 1977. A U-formed effect of maternal age and of parity was demonstrated. A marked interaction between the effects of these two variables existed. Two social groups were compared and the well-known high rate of LBW infants associated with low socioeconomic conditions was demonstrated. Standardization for the variables mentioned influenced this effect only little but reduced the difference between the social groups concerning infants above 3.5 kg weight. The background data were used for analysis of restricted geographical areas.

Adult↗
PubMed1987

Purine metabolism in normal and high-ITP human erythrocytes. Attempts to evaluate the ability to store the cells.

Storage of erythrocyte units from donors with ITP pyrophosphohydrolase deficiency have been studied and compared with units from normal donors. Verifying other investigations the incidence of this genetic disorder was found to be as high as about 3%. Hemolysis in the units was higher than in other units and there was a tendency to low total adenylate concentration. It is suggested that blood centers should organize a quality assurance program where one of the aims should be to detect genetic disorders that make the erythrocytes from the donors less suitable for long term liquid storage.

Adenosine Monophosphate↗
PubMed1986

An epidemiological study of work with video screens and pregnancy outcome: I. A registry study.

Three cohorts of women were identified with the aid of occupational codes in the census, linked to the Medical Birth Registry and an Inpatient Registry, containing information on women hospitalized for spontaneous abortion. The three cohorts were selected from the same socioeconomic stratum but had different probabilities to be exposed for video screen work: high, medium, and low. The total pregnancy outcome of the three groups of women did not differ significantly, but there was a weak trend for more spontaneous abortions and perhaps also for congenital malformations in the group with the highest video screen work exposure; however, the differences could be random. Comparisons of delivery outcomes for these cohorts in 1976-77 with those in 1980-81 did not show any consistent pattern in spite of the heavy computerization of these workplaces which occurred between the two time periods. The second part of this report studies the material in further detail.

Abortion, Spontaneous↗
PubMed1986

An epidemiological study of work with video screens and pregnancy outcome: II. A case-control study.

A case-control study on work with video screen equipment during pregnancy has been made for three cohorts of women, identified with the aid of occupational codes in the census, linked to the Medical Birth Registry and a registry containing information on women hospitalized for spontaneous abortion. Five hundred and twenty-two cases were selected (women with spontaneous abortions or women who had infants that died, had severe malformations, or had a birth-weight below 1,500 g) and 1,032 controls (women who had infants without any of these characteristics) taken from the same age stratum as the cases. All pregnancies had occurred in 1980-81. Questionnaires were mailed to the women asking for information on their work situation, including questions about work with video screen equipment. Fifty-eight women were excluded for various reasons. Response rate was 93%--lower (89%) among women with spontaneous abortions than among women who gave birth (95%). As stress and smoking were associated with video screen work, the effect of video screen work was analyzed after stratification for stress and smoking--no statistically significant effect of video screen work was seen but odds ratios were above 1. Crude odds ratios for video screen work were significantly elevated and showed a dose-dependent effect. This finding is discussed from the point of view of biases in the study: selective non-responding, recall bias, geographical variability, and lack of information on women who had induced abortions. Using questionnaire data for exposure rates in the populations studied, an estimate of the effect greater than or equal to 10 hr weekly work with video screens on spontaneous abortion rate was made. The point estimate was 1.04 with a 95% confidence interval of 0.9-1.2. Analysis of 44 infants with birth defects whose mothers had worked more than 10 hr/week with video screen equipment compared to 30 infants with birth defects whose mothers had not used such equipment in early pregnancy showed no signs of specificity in the type of birth defect.

Abortion, Spontaneous↗
PubMed1986

Effects of oxygen on red cells during liquid storage at +4 degrees C.

Red cells collected in CPD and suspended in SAGM medium were stored in plastic (PVC) containers for 42 days at +4 degrees C. Comparison was made between aerobic storage (normal air exposure) and anaerobic storage (exposure to nitrogen gas). The air-exposed units showed a strong increase in pO2 and oxygen saturation as a result of oxygen penetration into the bags from outside. This resulted in a decrease in ATP and adenylate energy charge, a slower metabolization of adenine and hypoxanthine to AMP and IMP, respectively, and a faster decrease in red cell fluidity. To explain the findings it is concluded that aerobic storage causes an increased need of high-energy phosphate groups, possibly used for replacement of the phospholipid membrane bilayer or in repair of phosphate bonds in the cytoskeleton. It is further proposed that a slight formation of hydrogen peroxide from free oxygen radicals moderately increases the oxidation of reduced (GSH) to oxidized (GSSG) glutathione and slightly enhances the need for reduced nicotinamide-adenine dinucleotides mainly provided by increased flux through the pentose phosphate shunt.

Adenosine Triphosphate↗
PubMed1986

Cesarean section and perinatal mortality in Sweden in 1981.

During the years 1973-81, the cesarean section (CS) birth rate increased from 5.5% to 12.4% in Sweden. During the same time, perinatal mortality declined from 12 to 7.1 per thousand children. The rates of CS and perinatal mortality, however, cannot be presented as reciprocally dependent variables without taking into consideration many of the other factors that have been at work during the same decade, e.g. improved results of the neonatologists in the lower weight groups, electronic fetal monitoring, use of steroids, introduction of tocolytic agents. The present study revealed that the incidence of CS could vary between 8% and 19% between different obstetric departments in Sweden during 1981. Despite this great difference in CS rate, no difference was noted in the rates of asphyxia or perinatal mortality. It is concluded that in the present study we have seen no indication that a marked increase in the CS rate would improve our present perinatal survival data and furthermore it still remains unproven that CS and perinatal mortality rates necessarily have a reciprocal relationship.

Asphyxia Neonatorum↗
PubMed1985

Metabolism of guanosine in human erythrocytes.

The metabolism of guanosine in human erythrocytes has been studied in two different experimental systems--direct incubation and dialysis incubation--the latter allowing continuous addition and removal of substances. Intra- and extracellular purine compounds were analyzed using high-performance liquid chromatography (HPLC). At 37 degrees C, a normal pH (7.4) and a favorably high concentration of inorganic phosphate, guanine nucleotides were synthesized at a substance rate of about 0.17 mmol . h-1 (calculated per liter erythrocytes) when guanosine was kept at a concentration of 25 mumol . l-1. At a higher guanosine concentration the rate of synthesis increased only moderately. Erythrocytes loaded with guanylates lost these nucleotides at a rate of 0.023 mmol . h-1 at a normal phosphate concentration and somewhat slower at a higher phosphate concentration. The metabolism kept the guanylates in an equilibrium that was similar to the equilibrium between the adenylates.

Blood Glucose↗
PubMed1985

Studies on the mechanism of human red cell loss of viability during storage at +4 degrees C in vitro. I. Cell shape and total adenylate concentration as determinant factors for posttransfusion survival.

Red cells stored in SAGM medium for 42 days at +4 degrees C were rejuvenated by bicarbonate, pyruvate and adenosine. Autologous 24-hour posttransfusion survival was determined in untreated as well as rejuvenated cells and showed an improvement from 77.4 +/- 4.7 to 89.2 +/- 7.2%. The erythrocyte adenylate energy charge decreased relatively more than the total adenylate concentration during storage, but the latter correlated better with posttransfusion red cell survival. Considerable deteriorations in red cell morphology (expressed as morphology index) and in deformability (measured as red cell fluidity) were observed during storage but were partly reversed by rejuvenation. The morphology index and the posttransfusion survival showed a significant correlation (r = 0.95, p less than 0.005) after, but not before, rejuvenation, indicating that the remaining changes are more permanent and decisive of survival. It is suggested that, in the proportion of stored erythrocytes which respond to rejuvenation, the capacity and time dependence of recovery of normal shape and flexibility are important.

Adenine↗
PubMed1985

A methodology for evaluating size at birth.

Data from the Swedish Medical Birth Registration, 1977-78, were utilized to develop methods of calculating reference standards for evaluating size at birth. Using the clinical information available, a 'healthy' sub-group was extracted. The individual distributions of birthweight (BW), birth length (BL) and birth headcircumference (BHc) at each week of gestational age (GA) were modelled following some truncation of their ranges. Application of the Box-Cox power family of transformations was generally found to improve the normality of the data. Certain percentages (such as 2.28, 50 and 97.72) were linked through a smoothing device. Features of the results include a positively skewed BW distribution in most GA weeks, a normal positively skewed BW distribution in most GA weeks, a normal distribution of BL and BHc at term, a larger relative variation in BW at lower GA than at term, and a distinct sigmoid shape of the median and other BW curves. Compared with five commonly quoted standards, the present data show the least deceleration in the fullterm region. Disregarding the clinical information, 'primary' sub-groups were also extracted using decomposing techniques. These gave rise to similar BW/GA relationships. Using data from the WHO comparative study, the method just mentioned was applied to standardize BW and BW-specific early neonatal mortality rates. This resulted in an improved description of biological events.

Birth Weight↗
PubMed1984

Pregnancy outcome and social indicators in Sweden.

Perinatal mortality, birth weight, the distribution of gestational age, and the relationship between gestational age and birth weight have been studied with regard to births reported to the Register of Births during 1976-77. In order to determine the influence of socio-economic factors on the parameters studied, the information from the birth register has been combined with that from the 1975 census in Sweden (including occupation of the mother, income of the family, type of family and housing standard). The total population of 190 024 infants was divided into three groups; 6915 infants (3.6%) were assigned to the most privileged group (group I) and 26 430 (13.9%) to the less privileged group (group III). The perinatal mortality rate did not differ significantly between group I and III. A comparison of the three groups showed a socio-economic difference as regards birth weight and the incidence of preterm as well as of postterm births. The less privileged group has a greater proportion of infants of low birth weight and of infants that were small for gestational age.

Birth Weight↗
PubMed1984

The incidence of congenital malformations in various socioeconomic groups in Sweden.

The incidence of congenital malformations reported to the Register of Births during 1976-77 in various socioeconomic groups were studied combining the informations from the birth register with that from the 1975 census (including occupation of the mother, income of the family, type of family and housing standard). The total population of 190 024 infants were divided into three groups; 6915 infants (3.6%) were assigned to the most privileged group (group I) and 26 430 (13.9%) to the less privileged group (group III). The total incidence of 5.01% of any malformation did not differ significantly between the groups. Neither was any variation found for specific malformation types, such as neural tube defects, cleft palate or morbus Down.

Congenital Abnormalities↗