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Biomedical subjects

Peter Nilsson

Publications and source records attributed to Peter Nilsson.

At least 73 records · Page 4Linked to original sources
PubMed2003

A new highly asymmetric chelation-controlled heck arylation.

This communication describes the development of a new highly asymmetric chelation-controlled Heck arylation. The methodology permits formation of 2-aryl-2-methyl cyclopentanones in good to very good two-step yields (45-78%) with excellent chiral enrichment (90-98% ee). In contrast to the well-known direct coupling to the enolate of a cyclic ketone, the Heck arylation of the corresponding N-methyl pyrrolidin enol ether requires neither a strong base nor a blocking of the alternative nonalkylated alpha-carbon. A chelated pi-intermediate is proposed to explain the excellent chiral induction.

Journal Article↗
PubMed2003

Single-nucleotide polymorphism analysis by allele-specific extension of fluorescently labeled nucleotides in a microfluidic flow-through device.

We describe a microfluidic approach for allele-specific extension of fluorescently labeled nucleotides for scoring of single-nucleotide polymorphism (SNP). The method takes advantage of the fact that the reaction kinetics differs between matched and mismatched configurations of allele-specific primers hybridized to DNA template. A microfluidic flow-through device for biochemical reactions on beads was used to take advantage of the reaction kinetics to increase the sequence specificity of the DNA polymerase, discriminating mismatched configurations from matched. The volume of the reaction chamber was 12.5 nL. All three possible variants of an SNP site at codon 72 of the p53 gene were scored using our approach. This work demonstrates the possibility of scoring SNP by allele-specific extension of fluorescently labeled nucleotides in a microfluidic flow-through device. The sensitive detection system and easy microfabrication of the microfluidic device enable further miniaturization and production of an array format of microfluidic devices for high-throughput SNP analysis.

Alleles↗
PubMed2003

Microwave-assisted high-speed PCR.

PCR amplification has emerged as a very important tool in biological research. The utility of the PCR is, however, hampered by the fact that it is a slow technique. Faster heating cycles are therefore needed, both to enhance the activity of the enzyme, and to enable shortening of the reaction times. In this paper, polymerase chain reactions with focused microwave irradiation as the source of heat were demonstrated for the first time. Thus, it was established that continuous microwave heating does not terminate the enzymatic function of the polymerase. The results indicate the possibility to shorten the total reaction time. In addition, the technique may give the possibility to perform PCR reactions in millilitre scale.

Microwaves↗
PubMed2003

Changes in gene expression in the wood-forming tissue of transgenic hybrid aspen with increased secondary growth.

Transgenic lines of hybrid aspen with elevated levels of gibberellin (GA) show greatly increased numbers of xylem fibres and increases in xylem fibre length. These plants therefore provide excellent models for studying secondary growth. We have used cDNA microarry analysis to investigate how gene transcription in the developing xylem is affected by GA-induced growth. A recent investigation has shown that genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under developmental-stage-specific transcriptional control. The present study shows that the highest transcript changes in our transgenic trees occurs in genes generally restricted to the early stages of xylogenesis, including cell division, early expansion and late expansion. The results reveal genes among those arrayed that are up-regulated with an increased xylem production, thus indicating key components in the production of wood.

Cell Wall↗
PubMed2003

Arylboronic acids as versatile coupling partners in fast microwave promoted oxidative Heck chemistry.

The useful and selective reactivity of arylboronic acids makes them favourite building blocks for many modern organic chemistry applications like the metal-mediated formation of C-C, C-O, C-N, and C-S bonds. This report describes oxidative Heck coupling reactions of arylboronic acids and olefins, which were conveniently and rapidly (5-30 min) carried out under air with temperature-controlled microwave heating. Different reaction conditions were investigated with regard to both microwave heating capability and chemical productivity. Copper(II) acetate was identified as a microwave compatible reoxidant of Pd(0). The scope and limitations of this high-speed chemistry protocol with diverse olefins and organoboronic acids are discussed.

Alkenes↗
PubMed2003

Gender differences in secondary prevention of coronary heart disease: reasons to worry or not?

OBJECTIVE: To analyse potential gender differences in cardiovascular risk factors and treatment patterns, reflecting clinical practice in secondary prevention. DESIGN: Observational national study during 3 years of patients eligible for secondary prevention of coronary heart disease (CHD). SETTING: Fifty-two healthcare districts in Sweden, involving primary health care and hospitals in collaboration, participating in a national quality assurance programme for the prevention of CHD. SUBJECTS: A national sample of male and female patients surviving acute myocardial infarction, or following CABG/PTCA interventions for CHD, controlled at 3-6 months (n = 9135) and 12 months (n = 4802) of follow-up. The proportion of female patients (25%) did not differ between visits. MAIN OUTCOME MEASURES: Self-reported data on lifestyle, drug treatment and cardiovascular risk factor levels after consultation in general practice or at hospital policlinics. RESULTS: No major gender differences were recorded in risk factor levels or in cardiovascular drug treatment patterns at 12 months of follow-up. Female patients participated in educational programmes to improve lifestyle to a higher degree than males (52.0 vs 45.1%), but after 1 year were more often (p < 0.001) self-reported smokers (11.7 vs 8.4%). Female patients showed higher levels of blood pressure, total cholesterol and HDL cholesterol, but not LDL cholesterol compared to male patients. CONCLUSIONS: In general, a gender-equal level of lipid control and access to medical drug treatment has been established for patients in secondary prevention from a national sample in Sweden, followed for 1 year after CHD manifestations and related interventions.

Coronary Disease↗
PubMed2003

Prospective follow-up study of 95 patients with edentulous mandibles treated according to the Brånemark Novum concept.

BACKGROUND: The long-term predictability reported with the traditional two-staged Brånemark method has led to developments aimed at simplifying the technique and reducing healing time. Results from a pilot study using the Brånemark Novum concept are promising, and it has been shown possible to fabricate and deliver an implant-supported fixed prosthesis to the patient on the day of surgery. PURPOSE: The objective of this study is to report clinical and radiographic outcomes in a group of patients treated according to the Brånemark Novum concept. MATERIALS AND METHODS: Ninety-five patients with edentulous mandibles were consecutively included in the study. Three specially designed fixtures were placed in each patient (285 fixtures in total) using drilling templates. The fixtures were immediately splinted with a prefabricated substructure, and fixed prostheses were delivered the same day in 67% of the patients. For the rest, prosthesis delivery ranged from 1 to 40 days (mean 5.6 d). Clinical and radiographic examinations were performed after 3 months, 6 months, 1 year, and then annually. The follow-up time was 1 to 5 years (mean 2.5 yr). RESULTS: The cumulative prosthesis survival rate was 99%. Eighteen fixtures (6.3%) failed in 13 patients. Kaplan-Meier survival estimates demonstrated a probability implant survival at 1 year of 95.0% (94 patients), at 3 years of 93.3% (47 patients), and at 5 years of 93.3% (9 patients). The mean bone loss was 0.73 mm between the examinations at 3 months and 1 year, 0.16 mm during the second year, and 0.13 mm annually during years 3 to 5. CONCLUSIONS: Comparable results, related to continuous prosthesis stability, were shown for the Novum approach compared with the traditional two-staged procedure. Survival of individual fixtures is lower when immediate loading is applied.

Adult↗
PubMed2002

[Diabetes and tobacco--a double health hazard].

Smoking is a serious risk factor for cardiovascular disease, retinopathy, and nephropathy in patients with diabetes. Furthermore, epidemiological studies have shown that heavy smokers run an increased prospective risk of developing type 2 diabetes, probably due both to the fact that smoking is a marker for an unhealthy lifestyle and that smoking via nicotine may deteriorate glucose metabolism by negatively influencing insulin sensitivity. In Sweden, data from the National Diabetes Register (NDR) has shown that the prevalence of smoking in type 2 diabetes patients followed in primary health care is almost as high as in the non-diabetic population, at least in middle-aged subjects (about 20%). This alarming situation must be dealt with by using new and effective methods to promote anti-smoking. If support by group sessions can be organised for patients with type 2 diabetes who are smokers, in combination with pharmacological approaches (nicotine, bupropion) it is hoped that the rate of smoking cessation can substantially increase. Such projects are currently under-way within the primary health care in southern Sweden.

Adult↗
PubMed2002

[Sleep disorders--a public health problem. Potential risk factor in the development of type 2 diabetes, hypertension, dyslipidemia and premature aging].

A large proportion of the adult population complains over difficulties in falling asleep, difficulties in maintaining sleep, or early awakening. Despite the fact that sleep disorders may be secondary symptoms to established or subclinical disease processes, more and more evidence has now accumulated to support the notion that sleep disorders may also play a primary role in the pathophysiology of cardiovascular disease. This has recently been documented in association with metabolic disturbances and impaired insulin action following experimental sleep deprivation. Sleep disorders may finally prove to be part of the pathophysiological chain linking adverse psychosocial stress with the metabolic syndrome, and ultimately premature ageing and early mortality.

Adult↗