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Biomedical subjects

G Petersson

Publications and source records attributed to G Petersson.

At least 19 recordsLinked to original sources
PubMed2001

Phenolic antioxidants in wood smoke.

Ten prominent dimethoxyphenols were determined in birchwood smoke from choked and open laboratory burning and in chimney smoke from a tiled stove. The structures of the methoxyphenols are similar to those of the well-known tocopherol and ubiquinol antioxidants. The 2,6-dimethoxyphenols characterising hardwood smoke are stronger antioxidants than the corresponding 2-methoxyphenols present mainly in softwood smoke. The antioxidant activity is highest for the 2,6-dimethoxyphenols with 4-alkenyl and 4-alkyl groups, which constitute 60-70% of the total amount of dimethoxyphenols. Phenolic antioxidants are scavengers of oxygen radicals and should be considered when health hazards of small-scale incomplete biomass burning are estimated.

Air Pollutants↗
PubMed2001

[Continuing should be a part of the clinical reality. Courage is required to see both the strong and the weak sides of the professional situation].

Continuing professional development (CPD) is a joint responsibility of the individual physician and the employer. CPD should focus on identification and documentation of the learning needs of the individual, based on professional demands. Reflection, feedback and evaluation of the results are central elements of the process. Efficient learning demands active participation; modern information technology is now becoming more widely available.

Curriculum↗
PubMed2001

Phenols and aromatic hydrocarbons in chimney emissions from traditional and modern residential wood burning.

The emissions from a traditional tiled stove consisted mainly of lignin-related methoxyphenols with antioxidant properties, and 1,6-anhydroglucose from cellulose degradation. A wood stove of presently introduced energy-efficient design for residential heating and hot-water supply was shown to emit small amounts of methoxyphenols and anhydrosugars from primary wood pyrolysis. Secondary harmful components like benzene and polycyclic aromatic hydrocarbons constituted a major portion of the organic emissions. It is concluded that differences in smoke composition are essential to consider in recommendations and rules for proper choices of wood burning devices.

Air Pollution↗
PubMed2001

Increased risks of circulatory diseases in late pregnancy and puerperium.

We studied a nationwide Swedish cohort with 654,957 women who had 1,003,489 deliveries from 1987 through September 1995 to assess late pregnancy and puerperal risks of circulatory diseases. We used standardized incidence rate ratios to calculate relative risks [with 95% confidence intervals (CIs)]. Compared with unexposed (nonpregnant and early pregnant) women, relative risks of venous thrombosis and pulmonary embolism during the third trimester were 6.7 (95% CI = 5.7--7.8) and 2.7 (95% CI = 1.7--4.2), respectively. Around delivery (from 2 days before to 1 day after delivery), the relative risks of all assessed circulatory diseases were dramatically increased: venous thrombosis, 115.1 (95% CI = 96.4--137.0); pulmonary embolism, 80.7 (95% CI = 53.9--117.9); subarachnoid hemorrhage, 46.9 (95% CI = 19.3--98.4); intracerebral hemorrhage, 95.0 (95% CI = 42.1--194.8); cerebral infarction, 33.8 (95% CI = 10.5--84.0); and myocardial infarction, 27.0 (95% CI = 0.6--180.0). During the rest of the first 6 weeks postpartum, the risks declined but were still substantially increased for all diseases, with the exception of subarachnoid hemorrhage. The results suggest that the increased risk for circulatory diseases related to pregnancy is mainly confined to a few days around delivery.

Adolescent↗
PubMed2000

Caffeine intake and the risk of first-trimester spontaneous abortion.

BACKGROUND: Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of spontaneous abortion, but the results have been inconsistent. METHODS: We performed a population-based, case-control study of early spontaneous abortion in Uppsala County, Sweden. The subjects were 562 women who had spontaneous abortion at 6 to 12 completed weeks of gestation (the case patients) and 953 women who did not have spontaneous abortion and were matched to the case patients according to the week of gestation (controls). Information on the ingestion of caffeine was obtained from in-person interviews. Plasma cotinine was measured as an indicator of cigarette smoking, and fetal karyotypes were determined from tissue samples. Multivariate analysis was used to estimate the relative risks associated with caffeine ingestion after adjustment for smoking and symptoms of pregnancy such as nausea, vomiting, and tiredness. RESULTS: Among nonsmokers, more spontaneous abortions occurred in women who ingested at least 100 mg of caffeine per day than in women who ingested less than 100 mg per day, with the increase in risk related to the amount ingested (100 to 299 mg per day: odds ratio, 1.3; 95 percent confidence interval, 0.9 to 1.8; 300 to 499 mg per day: odds ratio, 1.4; 95 percent confidence interval, 0.9 to 2.0; and 500 mg or more per day: odds ratio, 2.2; 95 percent confidence interval, 1.3 to 3.8). Among smokers, caffeine ingestion was not associated with an excess risk of spontaneous abortion. When the analyses were stratified according to the results of karyotyping, the ingestion of moderate or high levels of caffeine was found to be associated with an excess risk of spontaneous abortion when the fetus had a normal or unknown karyotype but not when the fetal karyotype was abnormal. CONCLUSIONS: The ingestion of caffeine may increase the risk of an early spontaneous abortion among non-smoking women carrying fetuses with normal karyotypes.

Abortion, Spontaneous↗
PubMed2000

Methoxyphenols from burning of Scandinavian forest plant materials.

Semivolatile compounds in smoke from gram-scale incomplete burning of plant materials were assessed by gas chromatography and mass spectrometry. Gas syringe sampling was shown to be adequate by comparison with adsorbent sampling. Methoxyphenols as well as 1,6-anhydroglucose were released in amounts as large as 10 mg kg(-1) of dry biomass at 90% combustion efficiency. Wood, twigs, bark and needles from the conifers Norway spruce and Scots pine emitted 12 reported 2-methoxyphenols in similar proportions. Grass, heather and birchwood released the same 2-methoxyphenols but also the corresponding 2,6-dimethoxyphenols which are characteristic of angiosperms. The methoxyphenols are formed from lignin and differ in structure by the group in para position relative to the phenolic OH group. Prominent phenols were those with trans-1-propenyl and ethenyl groups in that position. Vanillin, 4-hydroxy-3-methoxybenzaldehyde, was a prominent carbonyl compound from the conifer materials.

Forestry↗
PubMed1999

The influence of gestational age and smoking habits on the risk of subsequent preterm deliveries.

BACKGROUND: Previous preterm delivery and maternal smoking are associated with increased risks of preterm delivery. It is not known whether gestational age at the time of a preterm delivery is correlated with gestational age in successive preterm deliveries and whether changes in smoking habits influence the subsequent risk of preterm delivery. METHODS: We studied the associations among smoking habits, previous very preterm or moderately preterm delivery (before 32 weeks and at 32 to 36 weeks, respectively), and the risk of a subsequent very preterm or moderately preterm delivery in a population-based cohort of 243,858 women in Sweden between 1983 and 1993. The results were adjusted for covariates known to be associated with preterm delivery. RESULTS: The odds ratios for very or moderately preterm delivery in a subsequent pregnancy among women with a previous very preterm delivery, as compared with women who had a previous term delivery, were 12.4 (95 percent confidence interval, 9.1 to 17.0) and 7.1 (95 percent confidence interval, 6.0 to 8.4), respectively. Among women with a previous moderately preterm delivery, the corresponding odds ratios were 2.3 (95 percent confidence interval, 1.9 to 3.0) and 5.9 (95 percent confidence interval, 5.5 to 6.3), respectively. The odds ratios for a very preterm second delivery among the women who smoked 1 to 9 cigarettes per day and those who smoked 10 or more cigarettes per day, as compared with nonsmokers, were 1.4 (95 percent confidence interval, 1.1 to 1.7) and 1.6 (95 percent confidence interval, 1.3 to 2.0), respectively. The corresponding odds ratios for moderate preterm delivery were 1.3 (95% confidence interval, 1.2 to 1.4) and 1.5 (95 percent confidence interval, 1.4 to 1.6). The women who quit smoking between pregnancies were not at increased risk for very or moderately preterm delivery, whereas the women who started to smoke in the second pregnancy had the same risk as those who continued to smoke. CONCLUSIONS: The risk of a very preterm delivery in successive pregnancies is increased primarily among women with a previous very preterm delivery. Changes in smoking habits influence the risk of preterm delivery as well.

Adult↗
PubMed1998

Gas chromatographic and mass spectrometric analysis of 36 lignin-related methoxyphenols from uncontrolled combustion of wood.

Eighteen 4-hydroxy-3-methoxyphenyl (guaiacyl) compounds in wood smoke from spruce, and 18 4-hydroxy-3,5-dimethoxyphenyl (syringyl) analogues in birchwood smoke were analysed. Smoke samples were taken by a gas syringe from wood burning under varying but more or less choked conditions in laboratory pot experiments. Retention index data for a methylsilicone column and basic mass spectral data are given for all compounds. Retention index in combination with molecular mass and structure-specific fragment ions greatly facilitates qualitative analysis. The syringyl and guaiacyl analogues differ by 240 units in retention index and the matching structure-specific ions in their mass spectra by 30 mass units. The identified methoxyphenols differ in the structure of the sidechain, which may be lacking, an alkyl group, an alkenyl group, a carbonyl-containing group or an alcoholic moiety. The proportions between these groups of compounds varied strongly with combustion conditions whereas the proportions of phenols within them were quite specific for each group. The phenols with reactive olefinic linkages in the sidechain were present in larger proportions than reported in other studies of methoxyphenols.

Air Pollutants↗
PubMed1998

Production of CAL-programs in medicine, odontology and veterinary medicine in Sweden.

At the recommendation of the Swedish Government, the Council for the Renewal of Undergraduate Education was established in 1990. In 1993 the Council was declared a permanent National Agency by Swedish Parliament and became part of the newly established National Agency for Higher Education in 1995. The purpose of the Council for Renewal of Undergraduate Education is to promote and support endeavors to develop quality and renewal of undergraduate education. In particular the council awards grants to development activities. Once a year, teachers at Swedish universities, university colleges and professional schools can apply for funding. Applications are accepted for projects directed towards undergraduate education in all disciplines. The Council selects 15-20 projects and each project is funded for 1-3 years. An advisory group--MEDCAL (Computer Assisted Learning (CAL) in MEDicine, Odontology and Veterinary Medicine)--consisting of representatives from all universities supports the Council with registration and evaluation of programs, offers their opinions on the production of CAL and collaborates with similar organizations in other countries, e.g. Australia, Denmark, Germany, Great Britain and USA. In all, 12 projects within the frame of MEDCAL will be reported.

Computer-Assisted Instruction↗
PubMed1997

Isoprene from expired air inside a private car.

The concentration of isoprene inside a small-sized parked private car with one person was found to be of the order of 20 micrograms/m3. Isoprene was then the major non-methane volatile hydrocarbon except in strongly traffic-polluted parking places. On driving, with intermediate fan ventilation, the isoprene levels were one order of magnitude lower. In the empty car, the concentrations were still much lower, proving that isoprene originates predominantly from expired air. Air samples were taken on triple-layer adsorbent cartridges and were analysed for volatile hydrocarbons by gas chromatography after thermal desorption. The analytical aluminium oxide column permitted simultaneous determination of a range of reported traffic-emitted hydrocarbons including the carcinogenic 1,3-butadiene and benzene.

Air↗
PubMed1995

Tachykinin-induced nasal fluid secretion and plasma exudation in the rat: effects of peptidase inhibition.

Substance P (SP) evokes fluid secretion and plasma extravasation when applied to the nasal mucosa of rats. SP and another tachykinin, neurokinin A (NKA), are degraded in vitro by neutral endopeptidase (NEP) and angiotensin-1-converting enzyme (ACE). In this study, NKA or SP were applied locally to the nasal mucosa of rats. Subsequent fluid secretion was measured by a filter paper technique. Plasma exudation was derived as the recovery of intravenous (i.v.) administered 125I-albumin from the fluid-containing filter papers. In order to inhibit enzymatic degradation of the tachykinins by NEP and ACE, the rats were treated with i.v. administered phosphoramidon or captopril respectively or their combination. SP evoked fluid secretion that was augmented by phosphoramidon and further enhanced by adding captopril. NKA evoked nasal fluid secretion less effectively than SP and the effect was unaffected by peptidase inhibition. SP, but not NKA, evoked increased plasma exudation but only after pre-treatment with phosphoramidon.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Contralateral differences among biomarkers determined by a modified nasal lavage technique after unilateral antigen challenge.

The concentration of biomarkers from vessels and inflammatory cells in nasal lavage fluid reflects the degree of hyperresponsiveness in patients with allergic rhinitis. The lavage has usually been performed of both nasal cavities together after prewashings and administration of decongestants. To improve the technique, we introduced a modification involving lavage of the nasal cavities separately without any prewashings or decongestants. We challenged 20 rhinitic subjects sensitive to timothy unilaterally with timothy extract. In nasal lavages performed before, immediately after, and 6 h after the challenge, we determined the concentrations of albumin, histamine, bradykinin, TAME (N-alpha-tosyl-L-arginine methyl ester)-esterase, and leukotriene C4 (LTC4). In eight subjects, the procedure was repeated 1 and 2 weeks later. After the challenge, albumin, bradykinin, TAME-esterase, and LTC4 in the nasal lavage fluid increased on the ipsilateral side but not on the contralateral side. Histamine did not increase after antigen challenge. After 6 h, the biomarkers were not increased. The concentrations of biomarkers did not differ between sides before the challenge and not between visits. Thus, the modified nasal lavage technique is reliable and improved compared to previous methods because it involves reproducible determinations of different biomarkers, and it is simple and easy to perform.

Adolescent↗
PubMed1993

Budesonide inhibits plasma extravasation induced by capsaicin and by substance P in the rat nasal mucosa.

We studied the effect of the locally administered glucocorticoid budesonide on plasma extravasation induced by capsaicin and by substance P (SP) in the nasal mucosa of pathogen-free rats. Using Evans blue dye as a tracer, we measured plasma extravasation induced by capsaicin (150 micrograms kg-1 i.v.) or SP (0.5 and 2.5 micrograms kg-1 i.v.) in the rat naso- and maxilloturbinates after pretreatment with budesonide (0.1-50 micrograms twice/day for 2 days in the right nostril; 50 micrograms only for SP) or its vehicle. We found that budesonide inhibits plasma extravasation induced by capsaicin in a dose-dependent fashion in the nasal cavity. After the highest dose (50 micrograms) of budesonide, the values of Evans blue in the nasal mucosa were not different from the values observed after capsaicin vehicle alone. Budesonide also reduced plasma extravasation induced by capsaicin in the trachea and the urinary bladder of the rats in a dose-dependent fashion. Budesonide (50 micrograms) delivered to the nose inhibited the plasma extravasation caused by 0.5 but not by 2.5 micrograms SP kg-1 in the nasal mucosa. We conclude that the postjunctional part of the neurogenic pathway is a target for glucocorticoid antiinflammatory action in the nasal mucosa, at least of the rat. Budesonide's effect on organs other than the nose can be explained by systemic absorption.

Administration, Topical↗
PubMed1993

Assessment of ambient volatile hydrocarbons from tobacco smoke and from vehicle emissions.

Quantitative proportions of C2-C8 alkenes, alkadienes, alkynes, alkanes and arenes were determined for indoor smoky air and for air inside a private car. Samples were taken on adsorbent cartridges and analysed by gas chromatography on an aluminium oxide column. The proportions of more than twenty reported alkenes, alkadienes and alkynes were demonstrated to be very similar in a smoky room and in sidestream cigarette smoke. Isoprene, ethene and propene are major components. Urban air polluted by petrol-fuelled vehicles differs mainly by having much lower proportions of isoprene and much higher proportions of petrol alkanes and alkylbenzenes. The total concentration of C2-C8 hydrocarbons was found to be similar in a smoky room and in a car in urban traffic.

Chromatography, Gas↗
PubMed1993

Monoterpenes emitted to air from industrial barking of Scandinavian conifers.

Monoterpenes released to air were determined during single-log barking of timber at a saw-mill and during tumble drum barking of pulpwood at a TMP mill. Characteristic proportions of fourteen compounds were assessed by adsorbent sampling and gas chromatography. For Scots pine (Pinus sylvestris), the bicylic monoterpenes alpha-pinene and 3-carene predominated. For Norway spruce (Picea abies), alpha-pinene followed by beta-pinene were the major components. The proportions of beta-phellandrene and myrcene from spruce were remarkably high from barking compared to wood processing. Environmental aspects on the emissions are discussed.

Journal Article↗
PubMed1993

Photooxidant-forming monoterpenes in air plumes from kraft pulp industries.

Monoterpenes emitted to air from two Swedish kraft (sulphate) pulp-mills were determined by sampling on the Tenax adsorbent followed by laboratory analysis using thermal desorption combined with high-resolution gas chromatography. The composition of the terpenes was found to be similar in the emissions from various parts of the process as well as in the mill plume. The bicyclic terpenes alpha-pinene and 3-carene, originating principally from wood of Scots pine (Pinus sylvestris), predominated among the thirteen assessed hydrocarbon monoterpenes. Terpinolene was the most prominent among the particularly reactive terpenes with a lifetime in ozone-rich air of only a few minutes. The rapid formation of photooxidants by chemical reactions of the terpenes with other components of the mill plume is discussed. It is concluded that a variety of phytotoxic photooxidants are formed which may contribute significantly to forest decline within 50 km of mills located along coasts.

Journal Article↗