Biomedical subjects

P Nafstad

Publications and source records attributed to P Nafstad.

52 records · Page 3Linked to original sources

PubMed1996

Breastfeeding, maternal smoking and lower respiratory tract infections.

The objective of the study was to assess the relationship between breastfeeding and lower respiratory tract infections (LRTIs) during the first year of life, with special reference to maternal smoking. A cohort of 3,754 children born in 1992-1993 in the City of Oslo, Norway was recruited and data were collected at birth, 6 and 12 months of age. Complete information was obtained from 3,238 children (follow-up rate 86%). The main outcome was an episode of a LRTI, such as pneumonia, bronchitis or bronchiolitis, based on a self-administered questionnaire addressed to parents when the child was 6 and 12 months old. The outcome was specified as physician-diagnosed. In logistic regression analysis adjusting for confounding, maternal smoking increased the risk of LRTIs in children breastfed for 0-6 months (odds ratio (AOR) 1.7; 95% confidence interval (95% CI) 1.2-2.4), but not essentially when the child was breastfed for more than 6 months (AOR 1.1; 95% CI 0.7-1.6). Short-term breastfeeding (0-6 months) and no maternal smoking was related to an adjusted AOR of LRTIs of 1.3 (95% CI 1.0-1.7), and short-term breastfeeding combined with maternal smoking was related to an adjusted AOR of 2.2 (95% CI 1.6-3.1), as compared with long-term breastfeeding and no maternal smoking. The present study indicates a protective effect of long-term breastfeeding on the risk of lower respiratory tract infection during the first year of life. The results suggest that the protective effect is strongest in children exposed to environmental tobacco smoke.

Adult↗

PubMed1996

Lower respiratory tract infections among Norwegian infants with siblings in day care.

OBJECTIVES: The purpose of this study was to assess the role of siblings in day care as a determinant of infants' risk of lower respiratory tract infections. METHODS: A total of 3238 children (86%) out of 3754 Oslo, Norway, newborns recruited in 1992/93 were followed for 1 year. RESULTS: In logistic regression analysis, the risk of infection was increased in (1) infants with one or more siblings compared with infants without siblings (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.84, 2.85) and (2) infants with one or more siblings in day care compared with infants with siblings not in day care (adjusted OR = 1.7; 95% CI = 1.21, 2.26). CONCLUSIONS: The results suggest that siblings in day care outside the home increase infants' risk of lower respiratory tract infections.

Cohort Studies↗

PubMed1996

Fetal exposure to tobacco smoke products: a comparison between self-reported maternal smoking and concentrations of cotinine and thiocyanate in cord serum.

BACKGROUND: The objective of the study was to assess the relationship between maternal smoking habits and biomarkers of tobacco smoke measured in cord serum. METHODS: The study population comprised 202 mothers, 42 daily smokers, 24 occasional smokers and 136 nonsmokers. Information on maternal smoking habits was collected in a self-administered questionnaire at birth and compared with cotinine and thiocyanate concentrations in cord serum. RESULTS: In linear regression analysis, a unit increase in daily cigarette smoking corresponded to a 4.4 ng/ml (95% CI: 1.1-7.6) increase in cotinine concentration and 2.3 mumol/l(0.8-3.8) in thiocyanate. A cut-off point of 14 ng/ml cotinine separated well between daily smokers (88% above) and nonsmokers (96% below), but revealed a classification problem in occasional smokers (46% above). CONCLUSION: Cord serum cotinine and thiocyanate concentrations are related to daily smoking rate during pregnancy, but these concentrations vary considerably among occasional smokers. Detailed information on smoking habits is the key issue in understanding the adverse fetal effects of occasional smoking during pregnancy.

Adult↗

PubMed1995

Opposing placental gradients for thiocyanate and cotinine at birth.

In order to compare maternal and fetal exposure to compounds of tobacco smoke at the end of pregnancy, concentrations of cotinine and thiocyanate were measured in cord serum and maternal serum collected from 24 daily smoking and four non-smoking women at the time of child birth. The median level of thiocyanate (69 mumol/l) in maternal serum was about 50% higher than the median level (47 mumol/l) in cord serum (P < 0.0001) (Wilcoxon matched-pairs signed-ranks test). On the other hand, the median level of cotinine (22 ng/ml) in maternal serum was less than half of the median level (51 ng/ml) in cord serum (P = 0.0009). The correlation between maternal and cord serum was 0.77 (P < 0.0001) (Spearman's rank correlation coefficient) for thiocyanate levels and 0.90 (P < 0.0001) for cotinine. The high correlation between measurements of cotinine in maternal serum and cord serum indicates that maternal cotinine levels can be used to describe interindividual differences in fetal exposure to tobacco smoke. The placental gradients for cotinine and thiocyanate may indicate differences in maternal and fetal exposure to products of tobacco smoke.

Adult↗

PubMed1995

[Menarche and menstruation problems among teenagers in Oslo 1993].

Information on menarcheal age, menstruation habits and complaints was collected by means of questionnaires from 193 girls 14-17 years of age. Estimated median menarcheal age was 13.2 years. No statistical significant association was found between menarcheal age and physical activity or body mass. At the time of the data collection, 171 (95%) of the girls reported monthly menstruation while 29 reported loss of menstruation in more than three months during the period after menarche. 96 (52%) reported use of drugs against dysmenorrhoea, mainly paracetamol or non-steroid antiinflammatory drugs.

Adolescent↗

PubMed1995

Comparison of three methods for estimating environmental tobacco smoke exposure among children aged between 12 and 36 months.

BACKGROUND: The methods currently used for measuring environmental tobacco smoke (ETS) exposure among small children all have their limitations. The aim of this study was to compare the results of questionnaire assessments of children's ETS exposure with cotinine measurements in urine and nicotine measurements in hair, a new method for estimating average ETS exposure. METHODS: Questionnaire information on ETS exposure and a sample of hair were collected from 94 children aged 12-36 months. A urine sample for cotinine analysis was obtained from 72 of the children. RESULTS: Nicotine was found in all hair samples and cotinine in all urine samples. Compared to children registered as unexposed by the questionnaire, hair nicotine levels were 12.4 times higher among children exposed to more than 10 DNC (daily number of cigarettes) (P < 0.001) and 3.6 times higher among children exposed to 1-10 DNC (P < 0.001). The median cotinine creatinine ratio (CCR) was 2.4 times higher among children exposed to more than 10 DNC compared to unexposed children (P < 0.001). No significant difference in median CCR was found between unexposed children and children exposed to 1-10 DNC. The correlation coefficient was 0.64 between children's hair nicotine levels and DNC, 0.50 between CCR and DNC and 0.56 between children's hair nicotine levels and CCR. CONCLUSION: Nicotine measurement in hair is a practical and valid method for estimating average ETS exposure in children. An underreporting of ETS exposure was indicated.

Age Factors↗

PubMed1994

[Has sex education in schools resulted in later sexual debut? Experiences with a local preventive program].

Schoolteachers, nurses and doctors in primary health care in Stovner district, Oslo, have developed a new programme of sexual education for teenagers 14-16 years of age. The aim of the programme is to increase the knowledge about sexually transmitted diseases, reproduction and prevention of pregnancy and to open up for discussions within the classes about love, ethics, sexual abuse and sexual pressure. To evaluate the programme, pupils in the 9th grade in 1991 and 1993 (about 16 years old) answered a self-administered questionnaire. The answers showed an increase in knowledge about sexually transmitted diseases and reproduction, and a reduction in the percent of pupils who had sexual intercourse. The result should be cautiously interpreted, since changes in sexual knowledge and practices over time may have been caused by factors other than the intervention.

Adolescent↗

PubMed1994

Liver of juvenile Atlantic salmon, Salmo salar L.: a light, transmission, and scanning electron microscopic study, with special reference to the sinusoid.

BACKGROUND: This report provides a detailed description of sinusoidal and perisinusoidal structures in the normal liver of the juvenile Atlantic salmon (Salmo salar L.), a teleost species. METHODS: The liver was studied by light, transmission, and scanning electron microscopy, and organ specimens were sampled after retrograde, whole-body perfusion through the dorsal aorta using 3% glutaraldehyde. Detailed characterization of perisinusoidal stellate cells also included immunohistochemical staining for desmin and evaluation of autofluorescence of the same cells upon excitation in ultraviolet (UV) light. RESULTS: The sinusoid is lined by one cell type only: the endothelial cell. No intraluminal pit cells or Kupffer cells are present. The space of Disse contains reticulin fibres, visualized by Gomori's silver stain, and perisinusoidal stellate cells (PSC). PSC exhibited autofluorescence in UV light, indicating that these cells store vitamin A in cytoplasmic lipid droplets. Immunohistochemically, PSC were found negative for desmin. The space of Disse, extending deep down between adjacent hepatocytes, receives long, slender microvilli from parenchymal cells. In addition to scattered macrophages, interhepatocytic cells (IHC) are found perisinusoidally. Hepatocytes of Atlantic salmon form branching and anastomosing tubules. CONCLUSIONS: The sinusoids of Atlantic salmon liver are lined by a fenestrated endothelium, with PSC located in the space of Disse, with macrophages and IHC as inhabitants of the interhepatocytic space. IHC show ultrastructural similarities to mammalian pit cells and teleostean large granular lymphocytes, as well as to piscine monocytes. PSC might be storage cells for vitamin A in Atlantic salmon as shown by autofluorescence in these cells, while immunohistochemical studies indicate that desmin does not seem to be an adequate immunohistochemical marker for PSC in the juvenile Atlantic salmon. Methodologically, fixation for electron microscopy was performed by a new and convenient perfusion method: arterial retrograde whole body perfusion. Liver specimens intended for scanning electron microscopy were fractured at room temperature after prolonged osmium postfixation, leaving hepatocytes intact and producing images well suited to document the three-dimensional structure of cells and tissue.

Animals↗

PubMed1992

[Prevention of unwanted pregnancies in adolescents in a suburb--is it valuable?].

By counting cases of induced abortion among girls aged 15-19 years from 1988 to 1990 in Stovner district, Oslo, we evaluated a programme to prevent unwanted pregnancies among young women. The programme consists of several approaches, including free health services for teenagers at a special youth clinic, more education, at school and at youth clubs etc, in the use of contraceptives, and alcohol-free weekend arrangements. From 1988 to 1990 the number of abortions decreased from 35/1000 to 15/1000. Although this difference is significant (p < 0.01), one must be careful in drawing conclusions, owing to the small size of the sample.

Adolescent↗

PubMed1991

A study of modified lymphatics in the deep cortex of ruminant lymph nodes.

Ruminant lymph nodes, except when very small, were found to have a system of smooth-walled channels in the periphery of the 'deep cortical units' defined by Bélisle & Sainte-Marie (1981 a,b). Each channel originated with many 'blind' branches in the subnodular layer of the cortex and ended by joining a medullary sinus. The wall consisted of a continuous endothelial lining, a sometimes thin or discontinuous basement membrane without a basal lamina, and at least one layer of flattened reticular fibroblasts. The endothelium was higher than in most typical lymphatics, with a cytoplasmic fine structure similar to that of sinus-lining cells in the medullary sinuses. The intercellular junctions were generally long and elaborate. The lumen often contained opaque material, especially in the branches, as for initial lymphatics, as well as a few lymphocytes and an occasional nonlymphoid cell, but sinus macrophages were never seen. In some lymph nodes the lumen was crowded with lymphocytes. When small ferripolymaltose particles arrived in the node with the afferent lymph, many of them rapidly passed through the outer cortex and reached the lumen of the smooth-walled channels by way of the intercellular junctions of the endothelium. When colloidal carbon was introduced the same way, some of it also reached the channels where it accumulated in the basement membrane and in vesicles and vacuoles of the endothelium. These channels are interpreted as initial lymphatics of the same type as in other lymphoid organs rather than lymph node sinuses. They seem to play an important role for the exit of lymphocytes from the nodes and also for the passage of particulate material, including antigens, through those areas where recirculating lymphocytes arrive in the cortex.

Animals↗

PubMed1990

Reduced use of diagnostic obstetric ultrasound in Norway. Result of consensus panel recommending routine screening in pregnancy?

PURPOSE: To investigate the practice of obstetric ultrasound in Norway before and 2 years after a consensus conference recommending routine screening. Material, method: Two national representative materials sampled with a 2-year interval are compared. RESULTS: The average number of examinations was reduced from 2.46 to 2.2 (p = 0.014). Obstetrical institutions practising screening examined their patient less frequently than non-screening institutions (2.10 vs. 2.75 times, p less than 0.001 whereas in 1986 the converse was the case. CONCLUSIONS: Screening has become more widespread, and a more rational practice has developed.

Consensus Statements as Topic↗

PubMed1989

[Use of ultrasonics in obstetrics in 1988].

The Norwegian consensus conference on ultrasound in pregnancy 1986 stated that a beneficial effect of routine ultrasound examinations had not been scientifically proven. Despite this, the panel recommended that, on certain conditions, and in an effort to reduce the number of examinations performed, one examination should be offered to all pregnant women. A survey of the practice of ultrasound examinations has now been carried out. All Norwegian obstetrical institutions were invited to participate. Institutions covering 99.6% of births in Norway registered the number of examinations that had been performed on women delivering during a 7-day period. The main finding is a change in the practice of ultrasound in relation to a similar investigation in 1986: On average, each woman is now examined 2.23 times, compared with 2.46 in the 1986-survey. One or two examinations are now more common than in 1986, when a greater number of women were examined more often. Almost every pregnant woman is now examined with ultrasound, and there are now more institutions offering routine screening examination.

Female↗

PubMed1988

Effects of arterial pH and carbon dioxide on pancreatic exocrine H+/HCO3- secretion and secretin-dependent translocation of cytoplasmic vesicles in pancreatic duct cells.

To elucidate why arterial pH and carbon dioxide (PaCO2) modify the pancreatic H+/HCO3- secretory response to secretin stimulation, experiments were performed on anaesthetized pigs, recording the effects of arterial pH and PaCO2 on exocrine H+/HCO3- secretion and on morphology of pancreatic duct cells. Duct cells contained numerous cytoplasmic vesicles at secretory rest. Their number more than doubled during elevation of PaCO2 from 5.5 to 11.0 kPa. At arterial pH 7.40, maximal secretin stimulation cleared the cytoplasm of duct cells of more than 90% of the vesicles. At high PaCO2, this was accompanied by doubling the basolateral plasma membrane area and a 30% higher secretion rate than at PaCO2 5.5 kPa. Lowering arterial pH to 7.0 more than halved the secretin-induced vesicle clearance of duct-cell cytoplasm as well as exocrine H+/HCO3- secretion and abolished the secretin-dependent basolateral membrane area changes. Supramaximal secretin stimulation did not reverse the inhibitory effect of severe metabolic acidosis on secretion. It is concluded that PaCO2 and arterial pH may modify the secretory response to secretin through determining the incorporation of cytoplasmic vesicle material into the basolateral plasma membrane of duct cells.

Animals↗

PubMed1987

Disseminated intravascular coagulation in "Hitra disease" (hemorrhagic syndrome) in farmed Atlantic salmon.

Necropsy findings in adult salmon with subclinical "Hitra disease" (hemorrhagic syndrome) varied from negligible to hemorrhagic diathesis with generalized edema. By light microscopy, minute vessels were dilated, arterioles had mural necrosis, and thrombi were present. Occlusions consisted of fused erythrocytes and fibrin. Ultrastructurally, endothelial nuclei were pyknotic with condensed chromatin. The cytoplasm contained numerous laminar structures and electron-dense particles. Damaged erythrocytes adhered to the degenerated endothelium, and coalesced erythrocytes had formed mural thrombi or filled the vascular lumen. Microthrombi were frequently seen. There were no thrombocytes in the thrombi, which consisted of erythrocytes or reticulocytes. Clinically healthy farmed salmon parr showed the same disorders as did adults, but to a far lesser degree. Wild salmon parr had normal microvasculature. Results indicate that disseminated intravascular coagulation (DIC) occurs in "Hitra disease" in farmed Atlantic salmon.

Air Sacs↗

PubMedDate not supplied

Childhood asthma under the north face of Mount Everest.

We assessed prevalences of symptoms of asthma, allergic rhinitis, and atopic eczema and their associations with environmental exposures among school children living in high altitude and rural Tibet. After watching an asthma symptom video, 2.8% of the children reported ever wheezing at rest and 1.4% ever severe wheezing. Residential dampness problems were the only environmental exposure that was clearly associated with children's symptoms (odds ratios 1.3 to 2.5), even if several other exposures were common. The low symptom prevalences are in accordance with the hypothesis that the western lifestyle in some way increases the risk of asthma.

Adolescent↗

PubMedDate not supplied

Hair nicotine concentrations in mothers and children in relation to parental smoking.

The health effects of environmental tobacco smoke (ETS) exposure constitute a main public health problem. Lack of presice methods for assessing personal tobacco smoke exposure, makes it difficult to estimate the health effects of such exposure. Measuring hair nicotine concentrations could be an improvement in the assessment of personal tobacco smoke exposure. The objective of the present study was to estimate quantitatively the relation between hair nicotine concentrations in mothers and children and tobacco smoke exposure assessed by questionnaires. Mothers' and children's hair nicotine concentrations in the proximal 2 cm of hair were measured in 94 families with children 12-36 months of age: 25 nonsmoking families, 40 families with one smoking parent, and 29 families with both parents smoking. Questionnaire information on tobacco smoke exposure was collected from the same families. In multivariate linear regression analysis, children's nicotine levels were linearly related to daily number of cigarettes smoked at home by both mothers (0.8 mg/g increase per cigarette, 95% confidence interval [CI] 0.43-1.18), and fathers (1.3, 0.81-1.73). Mothers' nicotine levels were linearly related to both personal smoking (2.7, 1.75-3.55) and fathers' smoking at home (2.1,0.74-3.49). Hair nicotine seems to be a good quantitative measure of exposure to tobacco smoke during the previous months both among active and passive smokers. The non-invasive and simple collection procedure makes the method especially suitable for estimating tobacco smoke exposure in children.

Child, Preschool↗