Maternal dietary indexes are not linked to early childhood wheezing or atopic eczema

BACKGROUND

Several recent studies have investigated the association between maternal diet during pregnancy and wheezing or asthma in children. However, whether a specific dietary pattern during pregnancy protects children from wheezing or atopic diseases remains unclear. This study investigated the association between The Alternative Healthy Eating Index for Pregnancy (AHEI-P), the Dietary Inflammatory Index (DII), and the risk for wheezing and atopic eczema in children during the first year of life.

METHODS

This study included 1330 mother-child pairs who attended the Kuopio Birth Cohort (KuBiCo) study and had dietary information during the last trimester and information on children's health in the first year of life. AHEI-P and DII indicate a healthy diet and dietary inflammation potential during pregnancy. The AHEI-P and DII were compared with reported wheezing and doctor-diagnosed atopic eczema in children during the first year of life.

RESULTS

Neither AHEI-P nor DII is associated with wheezing or atopic eczema in children when analyzed by continuous variables and by tertiles. The odds ratio (95% CI) for AHEI-P and wheezing was 0.99 (0.98-1.01), for AHEI-P and atopic eczema1.01 (0.99-1.02), for DII and wheezing 1.02 (0.95-1.09), and for DII and atopic eczema 0.97 (0.91-1.04).

CONCLUSION

In this cohort study, AHEI-P and DII during pregnancy were not associated with wheezing or atopic eczema in the offspring during the first year of life.

Maternal caffeine, coffee and cola drink intake and the risk of gestational diabetes - Kuopio Birth Cohort

AIMS

Coffee intake is associated with a decreased risk of type 2 diabetes among non-pregnant people. We aimed to investigate the association between caffeine, coffee and cola drink intake in early pregnancy and the risk of gestational diabetes (GDM).

METHODS

Kuopio Birth Cohort (KuBiCo) is a prospective cohort study including pregnant women who were followed at the prenatal clinics in outpatient healthcare centers and gave birth in Kuopio University Hospital, Finland (n=2214). Maternal diet during the first trimester of pregnancy was assessed using a 160-item food frequency questionnaire. GDM was diagnosed by oral glucose tolerance test according to the Finnish national guidelines mainly between 24 and 28 gestational weeks.

RESULTS

Women with moderate coffee intake in the first trimester were less likely diagnosed with GDM than women without coffee intake in an age-adjusted model (OR 0.87; 95% CI 0.76-0.99; p = 0.03), but the association was attenuated in multi-adjusted models (p = 0.11). No association was found between caffeine intake and GDM. One third (32.4%) of pregnant women consumed caffeine over the recommendation (> 200 mg/d). Women who consumed cola drinks more than the median (33.3 mL/d) had an increased risk of GDM (OR 1.29; 95% CI 1.02-1.63, p = 0.037) in multi-adjusted model compared to those who consumed less.

CONCLUSIONS

Caffeine intake during the first trimester of pregnancy was not associated with the risk of GDM but a minor non-significant decrease was seen with moderate coffee intake. Although the average consumption of cola drinks was low in the KuBiCo cohort, higher consumption was associated with an increased risk of GDM. Further studies are needed to evaluate the safe amount of coffee during pregnancy, since the recommended caffeine intake was exceeded in almost half of the coffee drinkers.

Comparative steroid profiling of newborn hair and umbilical cord serum highlights the role of fetal adrenals, placenta, and pregnancy outcomes in fetal steroid metabolism

Previous steroid hormone studies concerning pregnancy and newborns have mainly focused on glucocorticoids; wider steroid profiles have been less commonly investigated. Here, we performed a comparative analysis of 17 steroids from newborn hair and umbilical cord serum at the time of delivery. The study participants (n = 42, 50% girls) were a part of the Kuopio Birth Cohort and represent usual Finnish pregnancies. The hair and cord serum samples were analyzed with liquid chromatography high resolution mass spectrometry and triple quadrupole tandem mass spectrometry, respectively. We detected high individual variations in steroid hormone concentrations in both sample matrices. The concentrations of cortisol (F), corticosterone (B), estrone (E1), estradiol (E2), dehydroepiandrosterone (DHEA), 11β-hydroxyandostenedione (11bOHA4), 5α-androstanedione (DHA4), and 17α-hydroxypregnenolone (17OHP5) correlated positively between cord serum and newborn hair samples. In addition, F and 11bOHA4 concentrations correlated positively with each other in both newborn hair and cord serum samples. The cortisone-to-cortisol ratio (E/F) was significantly higher in cord serum than in newborn hair samples reflecting high placental 11βHSD2 enzyme activity. Only minor sex differences in steroid concentrations were observed; higher testosterone (T) and 11-deoxycortisol (S) with lower 11bOHA4 in male cord serum, and higher DHEA, androstenedione (A4) and 11bOHA4 in female newborn hair samples. Parity and delivery mode were the most significant pregnancy- and birth-related parameters associating with F and some other adrenocortical steroid concentrations. This study provides novel information about intrauterine steroid metabolism in late pregnancy and typical concentration ranges for several newborn hair steroids, including also 11-oxygenated androgens.

Early-life environment and the risk of eczema at 2 years-Meta-analyses of six Finnish birth cohorts

BACKGROUND

Urban-related nature exposures are suggested to contribute to the rising prevalence of allergic diseases despite little supporting evidence. Our aim was to evaluate the impact of 12 land cover classes and two greenness indices around homes at birth on the development of doctor-diagnosed eczema by the age of 2 years, and the influence of birth season.

METHODS

Data from 5085 children were obtained from six Finnish birth cohorts. Exposures were provided by the Coordination of Information on the Environment in three predefined grid sizes. Adjusted logistic regression was run in each cohort, and pooled effects across cohorts were estimated using fixed or random effect meta-analyses.

RESULTS

In meta-analyses, neither greenness indices (NDVI or VCDI, 250 m × 250 m grid size) nor residential or industrial/commercial areas were associated with eczema by age of 2 years. Coniferous forest (adjusted odds ratio 1.19; 95% confidence interval 1.01-1.39 for the middle and 1.16; 0.98-1.28 for the highest vs. lowest tertile) and mixed forest (1.21; 1.02-1.42 middle vs. lowest tertile) were associated with elevated eczema risk. Higher coverage with agricultural areas tended to associate with elevated eczema risk (1.20; 0.98-1.48 vs. none). In contrast, transport infrastructure was inversely associated with eczema (0.77; 0.65-0.91 highest vs. lowest tertile).

CONCLUSION

Greenness around the home during early childhood does not seem to protect from eczema. In contrast, nearby coniferous and mixed forests may increase eczema risk, as well as being born in spring close to forest or high-green areas.

Vulvovaginal yeast infections, gestational diabetes and pregnancy outcome

BACKGROUND

The primary aim was to evaluate the association between gestational diabetes and blood glucose levels and vulvovaginal yeast infections in pregnancy. Secondly, we clarified the possible associations between maternal and prenatal factors, and birth outcomes and yeast infections.

METHODS

Three thousand nine hundred sixty-five pregnant women of the Kuopio Birth Cohort Study (KuBiCo) reported vulvovaginal yeast infections during pregnancy, via electronic questionnaires. Maternal and prenatal data, as well as clinical obstetric and early neonatal outcomes were registered during and after birth. The oral glucose tolerance test was performed on 3,079 women during pregnancy. Logistic regression analysis evaluated the possible multivariable associations between yeast infections, gestational diabetes and other prenatal and maternal factors.

RESULTS

No association was detected between gestational diabetes or blood glucose levels and vulvovaginal yeast infections during pregnancy. In multivariable analysis, women with yeast infections were more often multiparous, with higher education and had used more often antibiotics during pregnancy compared to others. No significant associations were detected in multivariable analysis between infections, the mode of delivery, preterm birth, birth weight or Apgar scores.

CONCLUSIONS

Women with reported vulvovaginal yeast infections managed generally well during pregnancy. They had no more gestational diabetes or higher blood glucose levels and their newborns managed equally well during early neonatal period.

An increased asthma risk continued until young adulthood after early-childhood hospitalisation for wheezing

AIM

The aim of this cohort study was to evaluate doctor-diagnosed and self-reported asthma in young adults after early-childhood hospitalisation for wheezing.

METHODS

In this prospective-controlled follow-up, questionnaires were sent to 95 subjects aged 24-28 years, who had been hospitalised for their first episodes of wheezing under 24 months of age. Fifty-eight cases and 100 controls returned the questionnaires.

RESULTS

The risk of doctor-diagnosed asthma was 2.14-fold (95% confidence interval 0.61-7.41), and the risk of self-reported asthma 2.39-fold (1.14-4.99) in cases compared to controls. The increased risk of self-reported asthma remained as statistically significant in analyses adjusted for current smoking, overweight and allergic rhinitis. Study subjects presented with wheezing symptoms, use of bronchodilators and inhaled corticosteroids, and with seasonal symptoms presumptive for allergic rhinitis during the last 12 months, more often than controls. The identification of a respiratory syncytial virus or rhinovirus during hospitalisation in early childhood was not anymore associated with asthma risk in adulthood. As expected, previous asthma during early childhood was a strong risk factor for asthma in young adulthood.

CONCLUSION

In this controlled questionnaire study, early-childhood hospitalisation for lower respiratory infection with wheezing was an independently significant risk factor of asthma in young adults.

The impact of postpartum depressive symptoms on self-reported infant health and analgesic consumption at the age of 12 months: A prospective cohort study

The infants of mothers with elevated depressive symptoms (EDS) postpartum appear to be at increased risk of somatic health problems during their first 12 months of life in low- and lower-middle-income countries. However, in higher-income countries, knowledge of this association is scarce. We sought to examine whether maternal reports of infant health problems, adherence to vaccination schedules and analgesic supply to the infant during the first 12 months of life differ between mothers with and without postpartum EDS. Altogether, 969 women who were enrolled in the Kuopio Birth Cohort study (www.kubico.fi) during 2012-2017 were included in this investigation. Depressive symptoms were measured with the Edinburgh Postnatal Depression Scale during pregnancy (1st and/or 3rd trimester) and at eight weeks postpartum. Infant health data were collected as a part of a 12-month online follow-up questionnaire for mothers and were based on self-reports of either maternal observations or physician-determined diagnoses. Postpartum EDS were associated with a 2- to 5-fold increased likelihood of abnormal crying and paroxysmal wheezing (based on parental observations), as well as gastroesophageal reflux and food allergy (based on physician-determined diagnoses). Mothers with postpartum EDS also supplied their infants with analgesic medication for longer periods. Adherence to vaccination schedules was similar between the examined groups. In conclusion, infants of mothers with postpartum EDS may be more likely to experience health problems or to be perceived by their mother as having health problems, and thus receive more medications.

A splice site and copy number variant responsible for TTC25-related primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder of motile cilia. With few exceptions, PCD is an autosomal recessive condition, and there are over 40 genes associated with the condition. We present a case of a newborn female with clinical features of PCD, specifically the Kartagener syndrome phenotype, due to variants in TTC25. This gene has been previously associated with PCD in three families. Two multi-gene panels performed as a neonate and at two years of age were uninformative. Exome sequencing was performed by the Care4Rare Canada Consortium on a research basis, and an apparent homozygous intronic variant (TTC25:c.1145+1G > A) was identified that was predicted to abolish the canonical splice donor activity of exon 8. The child's mother was a heterozygous carrier of the variant. The paternal sample did not show the splice variant, and homozygosity was observed across the paternal locus. Microarray analysis showed a 50 kb heterozygous deletion spanning the genes TTC25 and CNP. This is the first example of a pathogenic gross deletion in trans with a splice variant, resulting in TTC25-related PCD.

Effect of Social Distancing Due to the COVID-19 Pandemic on the Incidence of Viral Respiratory Tract Infections in Children in Finland During Early 2020

BACKGROUND

Social distancing measures are used to reduce the spreading of infection. Our aim was to assess the immediate effects of national lockdown orders due to coronavirus disease 2019 (COVID-19) on pediatric emergency room (ER) visits and respiratory tract infections in hospitals and nationwide in Finland.

METHODS

This register-based study used hospital patient information systems and the Finnish national infectious disease register. The participants were all patients visiting pediatric ER in 2 Finnish hospitals (Kuopio University Hospital, Mikkeli Central Hospital) covering 1/5th of the Finnish children population, 4 weeks before and 4 weeks after the start of the nationwide lockdown on March 16, 2020. Nationwide weekly numbers of influenza (A + B) and respiratory syncytial virus (RSV) in children were assessed from the infectious disease register from 2015 to 2020.

RESULTS

A major decrease in the rate of daily median pediatric ER visits was detected in both hospitals in the study during the nationwide lockdown compared with the study period before the lockdown (Mikkeli, 19 vs. 7, P < 0.001; Kuopio, 9 vs. 2,5, P < 0.001). The influenza season was shorter (8 weeks from peak to no cases), and the weekly rate of new cases decreased faster compared with the previous 4 influenza seasons (previously 15-20 weeks from peak to no cases). A similar decrease was also seen in RSV cases. No pediatric cases of COVID-19 were found in participating hospitals during the study period.

CONCLUSION

These results strongly suggest that social distancing and other lockdown strategies are effective to slow down the spreading of common respiratory viral diseases and decreasing the need for hospitalization among children.

Prospective study confirms that bronchiolitis in early infancy increases the risk of reduced lung function at 10-13 years of age

AIM

This study evaluated children hospitalised for bronchiolitis at less than six months of age to see if they had reduced lung function in early adolescence.

METHODS

We have prospectively followed 166 children hospitalised for infant bronchiolitis in 2001-2004 at Tampere University Hospital, Finland. At 10-13 years of age, flow-volume spirometry was measured in 89 cases and 108 controls without infant bronchiolitis from the local population register. Parameters of flow-volume spirometry before and after bronchodilation were analysed.

RESULTS

Forced expiratory volume in one second/forced vital capacity (FEV1/FVC) after bronchodilation was lower in cases than controls. FEV1 was pathological - under the 5th percentile of the national references - in 25% of cases and 12% of controls (p = 0.020) before bronchodilation and in 18% of cases and 5% of controls (p = 0.003) after bronchodilation. FEV1/FVC was pathological in 25% of cases and 13% of controls (p = 0.034) before bronchodilation. Logistic regression, adjusted for current asthma and maternal smoking, showed that infant bronchiolitis was associated with pathological FEV1 before (odds ratio 2.4) and after (odds ratio 4.4) bronchodilation. The result was similar for positive respiratory syncytial virus cases.

CONCLUSION

Reduced FEV1 after bronchodilation was found in early adolescence after infant bronchiolitis, suggesting irreversible bronchial obstruction.

National treatment guidelines decreased the use of racemic adrenaline for bronchiolitis in four Finnish university hospitals

AIM

Inhaled racemic adrenaline was used for bronchiolitis in many hospitals in Finland prior to new national current care guidelines for bronchiolitis in 2014, which limited its recommendations to on-demand rescue therapy. We studied the drug's use before and after the new guidelines to gauge changes in prescribing habits.

METHODS

This 2012-2016 study analysed how many 0.5 mL doses of racemic adrenaline were used for children by emergency rooms, paediatric wards and paediatric intensive care units at four university hospitals and estimated drug and staff costs.

RESULTS

There were substantial differences in the yearly consumption of racemic adrenaline between the hospitals before and after the bronchiolitis guidelines were published, with reductions in drug costs and staff time. The overall use more than halved during the study period, particularly in two hospitals where baseline consumptions were highest, but not in a third where baseline consumption was already low. In the fourth, the baseline consumption was modest and there was a constant decrease during the study years.

CONCLUSION

The current care guidelines for bronchiolitis had some impact on clinical practice, as the overall use of racemic adrenaline more than halved, but considerable differences remained in the four study hospitals after their publication.

Kuopio birth cohort - design of a Finnish joint research effort for identification of environmental and lifestyle risk factors for the wellbeing of the mother and the newborn child

BACKGROUND

A Finnish joint research effort Kuopio Birth Cohort (KuBiCo) seeks to evaluate the effects of genetics, epigenetics and different risk factors (medication, nutrition, lifestyle factors and environmental aspects) during pregnancy on the somatic and psychological health status of the mother and the child.

METHODS

KuBiCo will ultimately include information on 10,000 mother-child pairs who have given their informed consent to participate in this cohort. Identification of foetal health risk factors that can potentially later manifest as disease requires a repository of relevant biological samples and a flexible open up-to-date data handling system to register, store and analyse biological, clinical and questionnaire-based data. KuBiCo includes coded questionnaire-based maternal background data gathered before, during and after the pregnancy and bio-banking of maternal and foetal samples that will be stored in deep freezers. Data from the questionnaires and biological samples will be collected into one electronic database. KuBiCo consists of several work packages which are complementary to each other: Maternal, foetal and placental metabolism and omics; Paediatrics; Mental wellbeing; Prenatal period and delivery; Analgesics and anaesthetics during peripartum period; Environmental effects; Nutrition; and Research ethics.

DISCUSSION

This report describes the set-up of the KuBiCo and descriptive analysis from 3532 parturients on response frequencies and feedback to KuBiCo questionnaires gathered from June 2012 to April 2016. Additionally, we describe basic demographic data of the participants (n = 1172). Based on the comparison of demographic data between official national statistics and our descriptive analysis, KuBiCo represents a cross-section of Finnish pregnant women.

Asthma and lung function in adulthood after a viral wheezing episode in early childhood

BACKGROUND

Viral aetiology of infection has a significant role in the long-term outcome of early-childhood wheezing.

OBJECTIVE

This study examines asthma and lung function in adulthood after early-childhood wheezing induced by respiratory syncytial virus (RSV) and rhinovirus (RV).

METHODS

A total of 100 children were hospitalized for a wheezing episode at less than 24 months of age from 1992 to 1993 in Kuopio University Hospital (Finland). Adenovirus, influenza A and B virus, parainfluenza (1-3) virus, and RSV were tested on admission using antigen detection and antibody assays, and RSV and RV were tested by polymerase chain reaction (PCR). In 2010, 49 cases and 60 population controls attended a follow-up study, which included spirometry with bronchodilation test and fractionally exhaled nitric oxide (FE_NO ) measurements.

RESULTS

Current asthma was present in 64% of the cases with RV-induced wheezing (OR 17.0 [95%CI 3.9-75.3] vs controls), in 43% of the cases with RSV-induced wheezing episode (6.1 [1.5-24.9] vs controls), and in 12% of the controls. The RV group showed significantly higher mean FE_NO values than the RSV group and controls. RV-positive cases had lower MEF50 before bronchodilation and higher MEF50, FEV1, and FEV1/FVC bronchodilation responses than controls. RSV-positive cases had lower FVC than controls before bronchodilation.

CONCLUSION

Cases with RV- and RSV-induced early-childhood wheezing had increased risk for asthma in adulthood, and RV-positive cases had significantly higher FE_NO values than RSV-positive cases and controls. Compared to controls, RV-positive cases showed more bronchial reactivity, and RSV-positive cases showed lower FVC before bronchodilation in lung function testing.

CLINICAL RELEVANCE

Children with RV- or RSV-induced wheezing in early childhood have an increased risk for asthma and lung function abnormalities in adulthood.

Long-term effects of pneumococcal colonization during early childhood wheezing

BACKGROUND

Bacterial colonization during wheezing in early childhood has been associated with short-term relapses of wheezing, but no study has addressed the effects of Streptococcus pneumoniae colonization on long-term outcome of wheezing. The aim of the present study was therefore to evaluate whether pneumococcal (PNC) colonization during the first wheezing episode in early childhood is a determinant of asthma, atopy or lung function in the long term.

METHODS

In 1981-82 83 infants were hospitalized for first wheezing episode at <24 months of age. PNC colonization was defined as positive nasopharyngeal aspirate for S. pneumoniae either in culture or antigen detection on hospital admission. Atopy and repeated wheezing or asthma were diagnosed on all follow-up visits from infancy until the age of 28-31 years. Spirometry was conducted at the ages of 8-10, 18-20 and 28-31 years.

RESULTS

PNC colonization was found in 25/83 infants (30%) during hospitalization for wheezing in infancy. PNC colonization was not associated with later atopy, repeated wheezing, asthma or lung function at any time during the 30 year follow up.

CONCLUSION

PNC colonization during the first wheezing episode in early childhood is not a determinant of subsequent wheezing or later asthma, atopy or lung function in childhood, adolescence or adulthood.

Low eosinophils during bronchiolitis in infancy are associated with lower risk of adulthood asthma

BACKGROUND

Infant bronchiolitis may be the first manifestation of asthma.

AIM

To evaluate the association of early-childhood risk or protective factors for asthma and lung function reduction in adults 30 years after bronchiolitis in infancy.

METHODS

Forty-seven former bronchiolitis patients attended the clinical study at the median age of 29.5 years, including doctoral examination and measurement of post-bronchodilator lung function with flow-volume spirometry. Data on early-life risk factors including blood eosinophil counts on admission for bronchiolitis and on convalescence 4-6 weeks after bronchiolitis were available.

RESULTS

Low blood eosinophil count <0.25 × 10E9/l on admission for bronchiolitis was a significant protective factor and high blood eosinophil count >0.45 × 10E9/l on convalescence was a significant risk factor for asthma in adulthood independently from atopic status in infancy. Parental asthma and high blood eosinophil count >0.45 × 10E9/l during bronchiolitis were significant risk factors for irreversible airway obstruction (FEV1/FVC ratio below the 5th percentile lower limit of normality after bronchodilation).

CONCLUSION

Our adjusted analyses confirmed that eosinopenia during infant bronchiolitis predicted low asthma risk and eosinophilia outside infection predicted high asthma risk up to the age of 28-31 years. Parental asthma and eosinophilia during bronchiolitis were recognized as risk factors for irreversible airway obstruction.

Adults face increased asthma risk after infant RSV bronchiolitis and reduced respiratory health-related quality of life after RSV pneumonia

AIM

To evaluate the association between hospitalisation for respiratory syncytial virus lower respiratory tract infection (RSV LRTI) in infancy and asthma, respiratory health-related quality of life and lung function at 28-31 years of age.

METHODS

In 2010, we carried out a 30-year follow-up on 43 adults admitted to Kuopio University Hospital, Finland, for RSV LRTI, 27 for bronchiolitis and 16 for pneumonia, between 1981 and 1982. Together with 86 population-based controls, they completed the Saint George's Respiratory Questionnaire and underwent prebronchodilator (pre-BD) and post-BD spirometry tests to measure percentage of predicted forced vital capacity (FVC%), percentage of predicted forced expiratory volume in 1 sec (FEV1%) and percentage of predicted FEV1/FVC (FEV1/FVC%).

RESULTS

Both the pre-BD and post-BD FEV1% and FEV1/FVC% were significantly lower in former RSV LRTI patients than in the controls. The bronchiolitis patients had more asthma in adulthood than the controls and pneumonia in infancy was associated with lower St George's Respiratory Questionnaire (SGRQ) scores.

CONCLUSION

Respiratory tract infection LRTI hospitalisation in infancy was associated with an increased risk of permanent obstructive lung function reduction in adulthood. The asthma risk was higher after hospitalisation for bronchiolitis, than in the controls, and respiratory health-related quality of life was lower after hospitalisation for pneumonia.

Increased asthma risk and impaired quality of life after bronchiolitis or pneumonia in infancy

BACKGROUND

Recent studies have revealed that adulthood asthma has its origin in early childhood.

AIM

The aim of the present study was to evaluate the prevalence of asthma and respiratory health-related quality of life in adults 30 years after hospitalization for bronchiolitis or pneumonia in infancy.

METHODS

Patients who were hospitalized for bronchiolitis or pneumonia at age under 24 months in 1981-1982 have been followed in repeated visits. In 2010, 48 of the 83 former patients with bronchiolitis (57.8%), 22 of the 44 former patients with pneumonia (50.0%), and 138 matched controls participated in the clinical study at the age of 28-31 years. The participants completed a structured questionnaire on respiratory symptoms, the Saint George's Respiratory Questionnaire (SGRQ), and underwent 2-week peak expiratory flow (PEF) monitoring. Asthma was defined as doctor-diagnosed and self-reported asthma based on doctor-prescribed medication for asthma, the presence of asthma-presumptive symptoms, and the results of home PEF monitoring.

RESULTS

Both doctor-diagnosed asthma (31.3% vs. 10.9% adjusted P = 0.002) and self-reported asthma (35.4% vs. 14.5% 0.003), as well as repeated on-demand use of bronchodilators (35.4% vs. 14.5% 0.002), and regular use of inhaled corticosteroids (20.8% vs. 8.7% 0.023) were more common in former bronchiolitis patients than in controls. Former bronchiolitis and pneumonia patients had higher total SGRQ scores than controls. The median scores were 5.4 (IQ(25-75) 0.0-14.7, P < 0.001) in bronchiolitis group, 4.9 (1.3-14.8, 0.012) in pneumonia group compared to controls 1.5 (0.0-6.0).

CONCLUSION

Hospitalization for bronchiolitis in infancy is associated with an increased risk of asthma, and an increased use of asthma medication in adulthood at the age of 28-31 years. Impaired respiratory health-related quality of life in adulthood as measured by the SGRQ is present after bronchiolitis and pneumonia in infancy.

Factors associated with the self-care of home-dwelling elderly

The purpose of this study was to examine how functional capacity, activities of daily living (ADL), instrumental activities of daily living (IADL), life satisfaction and self-esteem are related to the self-care behaviour styles of home-dwelling elderly persons. Data were collected by qualitative interviews (self-care) and structured interviews (functional capacity, life satisfaction and self-esteem) from home-dwelling elderly persons (n=40) aged 75 or more. The persons were living in a medium-sized city in northern Finland. The qualitative data were analysed using deductive content analysis. The classification frame consisted of a theoretical classification developed in an earlier study. The categories were quantified and the relationship between the variables analysed by cross-tabulation. The persons whose self-care behaviour style was responsible, formally guided or independent carried out their daily activities without assistance from others, while those who showed abandoned self-care did not manage their daily activities without help. Life satisfaction was the highest among the formally guided persons and self-esteem among the responsible ones. Poor life satisfaction and self-esteem correlated with abandoned self-care behaviour.

Model for the self-care of home-dwelling elderly

The aim of this study was to develop a model to clarify the existing knowledge concerning the self-care of home-dwelling elderly people. The data were collected in Oulu, a medium-sized city in northern Finland, by interviewing 40 home-dwelling elderly persons aged 75 or more. Data were analysed using the constant comparative method of the grounded theory approach. The model consists of four modes of self-care with different conditions for action and different meanings: responsible self-care consists of responsible activity by the elderly person based on a positive orientation towards the future and a positive experience of ageing. The meaning of responsible self-care is a desire to continue living as an active agent. Formally guided self-care consists of uncritical observance of instructions and routine performance of daily tasks. This approach is based on life experiences of taking care of others and realistic awareness of the effects of old age. The meaning of formally guided self-care is a tendency to accept life as it comes. Independent self-care is based on the person's desire to listen to his/her own internal voice. These persons aim to manage in life independently and deny the prospect of growing old. The meaning of independent self-care is an attempt to maintain the constancy of life. Abandoned self-care is characterized by helplessness and lack of responsibility. It involves bitterness and a negative attitude towards ageing. The meaning of abandonment is a desire to 'give up'. According to this study, self-care is not a separate part of old men's or women's lives, it is associated closely with their past life and with the future. As an activity, self-care is not just a rational way to maintain health. It also reflects the person's overall attitude towards health care, illnesses and manner of living.

Challenges of the grounded theory approach to a novice researcher

The grounded theory approach has been used in nursing research since 1970. The latest methodological books describe the research process in detail. However, there are many problems involved in the grounded theory approach, which especially need to be considered by a novice researcher. One of these problems is the question of how deeply and widely the researcher should familiarize her- or himself with the research topic before the empirical study. The problems also include the need to focus the research problem and to choose the sampling method. Data analysis is a multistage process, which demands from the researcher both sensitivity and time to work out the findings which emerge from the data. In this paper, the grounded theory approach is described as a process undertaken by the novice researcher. The purpose of this paper is to discuss the challenges of the grounded theory approach and the problems encountered by a researcher using the method for the first time.

[Challenges of the grounded theory approach to a novice researcher]

The grounded theory approach has been used in nursing research since 1970. The latest methodological books describe the research process in details. However, there are many problems involved in the grounded theory approach, which especially need to be considered by a novice researcher. One of these problems is the question of how deeply and widely the researcher should get familiar with the research topic before the empirical study. The problems also include the need to focus the research problem and to choose the sampling method. Data analysis is a multistage process, which demands from the researcher sensitivity and time to work out the findings which emerge from the data. In this paper, the grounded theory approach is described as a process undertaken by the researcher. The purpose of this paper is to discuss the challenges of the grounded theory approach and the problems encountered by a researcher using the method for the first time.

Appendix. Cloning and sequence of the gene encoding enzyme E-1 from the methionine salvage pathway of Klebsiella oxytoca

The methionine salvage pathway converts the methylthioribose moiety of 5'-(methylthio)-adenosine to methionine via a series of biochemical steps. One enzyme active in this pathway, a bifunctional enolase-phosphatase called E-1 that promotes oxidative cleavage of the synthetic substrate 2,3-diketo-1-phosphohexane to 2-keto-pentanoate, has been purified from Klebsiella pneumoniae and is characterized in the preceding paper (Myers, R., Wray, J., Fish, S., and Abeles, R. H. (1993) J. Biol. Chem. 268, 24785-24791). We synthesized degenerate oligonucleotides corresponding to portions of the amino terminus of E-1. These oligonucleotides were used as polymerase chain reaction primers on whole genomic DNA from Klebsiella oxytoca. This resulted in an 82-base pair DNA fragment that was used as a hybridization probe to obtain a clone of the E-1 gene from a K. oxytoca gene library. The DNA sequence of the E-1 coding region was determined, and the amino acid sequence of E-1 was deduced. E-1 appears to represent a novel class of enzymes since no homology to known enzymes was found. Cloning the gene from K. oxytoca on a multicopy plasmid leads to overproduction of E-1 enzyme that has properties indistinguishable from those of the enzyme from K. pneumoniae.

Inactivation of a volume-sensitive basolateral potassium conductance in turtle colon: effect of metabolic inhibitors

Previous work has shown that the basolateral membrane of turtle colon epithelium contains a quinidine-sensitive potassium conductance which can be activated by osmotic cell swelling. In this work and in the present study, potassium flow across the basolateral membrane was measured as a short-circuit current across intact pieces of epithelial tissue in which amphotericin B was used to permeabilize the apical membrane. Quinidine-sensitive currents were generated when the mucosal bath contained chloride, a permeant anion. Replacement of chloride by sulfate or addition of sucrose to the bathing solutions abolished 75-90% of the current and caused the quinidine-inhibitable fraction of the current to go from over 90% to around 6%--suggesting that decreases in cell volume had brought about inactivation of the quinidine-sensitive conductance. When metabolic inhibitors were present, inactivation of the conductance by these maneuvers was prevented. Activation of the conductance by replacement of mucosal SO4 by Cl, however, was not affected.

Controllable alteration of cell genotype in bacterial cultures using an excision vector

We have used recombinant DNA techniques to construct a derivative of phage lambda, called an excision vector, which retains only those functions necessary for conditional maintenance of lysogeny and integration/excision. The tyrA+ gene was cloned on this excision vector, integrated into the Escherichia coli chromosome, and stably maintained and expressed under permissive conditions. Upon shift to non-permissive conditions, the excision vector and its passenger gene were very efficiently excised from the chromosome and lost, leaving a culture of Tyr- bacteria. This illustrates a new class of conditional mutations in which the genotype changes in response to external stimuli.

Genetic separability of the chorismate mutase and prephenate dehydrogenase components of the Escherichia coli tyrA gene product

Fragments of the tyrA gene of Escherichia coli, when suitably engineered, can express either the chorismate mutase activity or the prephenate dehydrogenase activity without the other.

Tetracycline resistance determined by pBR322 is mediated by one polypeptide

Only one polypeptide specified by plasmid pBR322 is necessary to determine tetracycline resistance. Small deletions in pBR322 constructed in vitro which result in the lack of ability to confer tetracycline resistance in vivo also result in the absence or alteration of this polypeptide in vivo. Other deletions define the extent of material necessary to encode this polypeptide. A correction to the DNA sequence of the tetracycline resistance cistron has been determined which confirms these observations.

Characterization of a gene, glnL, the product of which is involved in the regulation of nitrogen utilization in Escherichia coli

DNA was prepared from a strain of Escherichia coli bearing a mutation which confers the GlnC phenotype (inability to reduce the expression of glnA and other nitrogen-regulated operons in response to ammonia in the growth medium). A fragment of this DNA carrying glnA, the structural gene for glutamine synthetase, was cloned on plasmid pBR322. By using recombination in vitro, we mapped the GlnC mutation to a region between glnA and glnG. This region defines a gene, glnL, which codes for a trans-acting product; the GlnC mutant produces an altered product. The glnL product plays a key role in the communication of information concerning the quality and abundance of the nitrogen source in the growth medium to a destination responsible for the regulation of glnA and other genes for enzymes responsible for nitrogen utilization.

Physical and genetic characterization of the glnA--glnG region of the Escherichia coli chromosome

We have cloned and characterized a fragment of the Escherichia coli chromosome spanning glnA, the structural gene for glutamine synthetase (L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2]. The fragment also carriers glnG, whose product is necessary for regulation of glnA expression, and a previously unidentified gene whose function we have not discovered. Transcription of glnA and the newly identified gene occurs divergently from a region between the two genes. Transcription of glnA proceeds toward glnG, which is transcribed in the same direction. A region of DNA between glnA and glnG contains genetic information whose loss may result in the inability to reduce expression of glnA and other operons in response to ammonia (the GlnC phenotype).

A plasmid cloning vehicle allowing a positive selection for inserted fragments

We describe a plasmid cloning vehicle, pTR262, which allows a strong positive selection (resistance to tetracycline) for transformants bearing plasmids which have DNA insertions. pTR262 is derived from plasmid pBR322 and contains the cI gene and adjacent regulator region oRpR or the bacteriophage lambda. The expression of the tetracycline resistance (tet-r) gene(s) in pTR262 requires transcription from pR and is repressed by the cI gene product, lambda repressor. Insertion of a DNA fragment into the HindIII or Bc/I sites in pTR262 inactivates the cI gene and allows expression of the tet-r gene(s) in the host bacterium. A 100-fold increase in the number of tetracycline-resistant transformants is obtained when HindIII- or Bc/I-generated fragments are added to a ligation mixture containing HindIII- or Bc/I-digested pTR 262 DNA.

A cautionary note on the use of certain restriction endonucleases with methylated substrates

Methylation of adenine and cytosine residues in DNA isolated from common strains of Escherichia coli K-12 can render that DNA resistant to cleavage by certain restriction endonucleases at those sites at which the recognition sequence for such an endonuclease overlaps (but does not include) a sequence recognized by methylases specified by the dam or dcm gene.

A general method for the purification of restriction enzymes

An abbreviated procedure has been developed for the purification of restriction endonucleases. This procedure uses chromatography on phosphocellulose and hydroxylapatite and results in enzymes of sufficient purity to permit their use in the sequencing, molecular cloning, and physical mapping of DNA.

Maximizing gene expression on a plasmid using recombination in vitro

Recombination in vitro has been used to place one or more copies of a strong promoter, the lac promoter, at varying distances from the cl (repressor) gene of bacteriophage lambda on the E. coli plasmid pMB9. In all constructions, lambda repressor synthesis is driven wholly or predominantly by the inserted lac promoter. One of our fusions directs the synthesis of very high levels of lambda repressor. In this case, the fused DNA encodes a ribosome binding site which is a "hybrid" of lambda and lac sequences. In principle, this method of construction should elicit high levels of expression in E. coli of any gene, whatever its source. We also described strains with different sequence arrangements that, for reasons not completely understood, produce less repressor.

Use of phage immunity in molecular cloning experiments

Immunity to phage superinfection is a useful selective marker in molecular cloning experiments. Plasmids which have unique sites for several different restriction endonucleases and which specify immunity to bacteriophage are described.

Construction of plasmids carrying the cI gene of bacteriophage lambda

By techniques of recombination in vitro, we have constructed a plasmid bearing the repressor gene (cI) of bacteriophage lambda fused to the promoter of the lac operon. Strains carrying this plasmid overproduce lambda repressor. This functional cI gene was reconstituted by joining DNA fragments bearing different parts of that gene. Flush end fusion techniques, involving no sequence overlap, were necessary for the construction; in certain cases, the abutting of the DNA molecules bearing ends generated by different restriction endonucleases creates a sequence at the junction which is recognized by one of the restriction endonucleases.

Recognition sequences of repressor and polymerase in the operators of bacteriophage lambda

Nucleotide sequences in two wild-type and six mutant operators in the DNA of phage lambda are compared. Strikingly similar 17 base pair units are found which we identify as the repressor binding sites. Each operator contains multiple repressor binding sites separated by A-T rich spacers. Elements of 2 fold rotational symmetry are present in each of the sites. Superimposed on each operator is an E. coli RNA polymerase recognition site (promoter). Similarities in the sequences of the two lambda promoters, a lac promoter, and an E. coli RNA polymerase recognition site in SV40 DNA are noted.