PubMed Health⌕ Search

Biomedical subjects

Peter Larsson

Publications and source records attributed to Peter Larsson.

13 recordsLinked to original sources
PubMed2006

Serotypes of Streptococcus pneumoniae isolated from blood and cerebrospinal fluid related to vaccine serotypes and to clinical characteristics.

Pneumococci isolated from blood and cerebrospinal fluid from 1998 to 2001 in 2 counties in south-west Sweden were serotyped with the capsular reaction test. Of the 836 strains, 353 (42%), 598 (72%) and 789 (94%) belonged to serotypes included in the 7- and 11-valent pneumococcal conjugate vaccines and in the 23-valent polysaccharide vaccine, respectively. The most common serotype was type 1 (119 isolates) followed in descending frequency by serotypes 7F, 9V, 14, 4 and 12F (90-49 isolates per serotype). The coverage rates of the 7- and 11-valent conjugate vaccines among 58 strains isolated from children and adolescents 0-19 y of age were 46% and 93%, respectively. A comparison of clinical characteristics of infections caused by different serotypes showed that types 1 and 7F were less commonly associated with severe underlying diseases, that patients infected with these serotypes were younger than the average and, thus, had a lower case-fatality rate.

Adolescent↗
PubMed2006

In vitro activities of three carbapenems against recent bacterial isolates from severely ill patients at Swedish hospitals.

To study the in vitro activity of imipenem, meropenem and ertapenem against common pathogens isolated from patients in intensive care, haematology and dialysis/nephrology units at 7 Swedish university hospitals, a total of 788 isolates were collected during 2002-2003. The distribution of the isolates was as follows: Escherichia coli (n = 140), Klebsiella spp. (n = 132), Proteus spp. (n = 97), Enterobacter spp. (n = 113), Pseudomonas aeruginosa (n = 126), Acinetobacter spp. (n = 53) and Enterococcus faecalis (n = 127). The susceptibility to the 3 carbapenems was determined by E-test, and the MICs were interpreted according to SRGA criteria. All 3 carbapenems were highly active against Enterobacteriaceae. The overall susceptibility to imipenem, meropenem and ertapenem was 90%, 98% and 93%, respectively. Against Enterobacteriaceae, Enterobacter spp. excluded, ertapenem had an equal or lower MIC(90) than meropenem. Apart from being the most active carbapenem against Enterobacteriaceae, meropenem was also the most active carbapenem against P. aeruginosa, whereas imipenem was the most active drug against Acinetobacter spp. The carbapenems are still potent antibiotics. With the introduction of ertapenem, and an expected increase in the carbapenem consumption due to an increased prevalence of strains with extended-spectrum beta-lactamases, continuous surveillance of carbapenem resistance appears to be warranted, with special attention to P. aeruginosa, Enterobacter and Proteus spp.

Acinetobacter↗
PubMed2005

The vulvar skin microenvironment: impact of tight-fitting underwear on microclimate, pH and microflora.

The aim of the present study was to investigate if tight-fitting underwear (string panties) equipped with string panty liners affected the vulvar skin microenvironment differently to regular panties with standard panty liners. Thirty-two healthy women participated in a crossover study where temperature, humidity, surface pH and aerobic microflora were measured on vulvar skin. Vulvar skin temperature was 35.2 +/- 0.19 (mean +/- SEM) and 35.3 +/- 0.17 degrees C, respectively, for the two underwear systems. Mean humidity and mean skin surface pH at vulvar skin did not differ between the two systems. Barely noticeable differences were found for the aerobic microflora both at labium majus and at perineum. The mean total number of microorganisms in the two different panty liners was the same, 6.0 +/- 0.15 and 6.0 +/- 0.16, respectively (log CFU per panty liner). The differences in panty and panty liner design studied seem to have negligible impact on the vulvar skin microclimate, skin surface pH and aerobic microflora. No support was found for the assumption that a string panty system would result in higher contamination of vulvar skin by anorectal microflora.

Adult↗
PubMed2005

The in vitro activity of pentane-1,5-diol against aerobic bacteria. A new antimicrobial agent for topical usage?

Multi-resistance to antibiotic therapy and to biocides is becoming increasingly common, which has led to mounting concern worldwide regarding the future use of traditional antimicrobials. Diols or glycols also have antimicrobial effects. Pentane-1,5-diol has low oral toxicity, is essentially non-irritating to the skin and has high antimicrobial activities against bacteria, fungi and viruses. The effect of pentane-1,5-diol against both sensitive and multi-resistant Gram-positive and Gram-negative bacteria was tested in vitro against 85 bacterial strains showing minimal inhibitory concentrations in the range of 2.5 to 15.0% (vol/vol) against both antibiotic-susceptible and multi-resistant aerobic bacteria. The exact mechanism of action is unknown but probably pentane-1,5-diol sucks water out of the bacterial cells which then collapse, a mechanism to which it is probably very difficult to develop resistance. The high activity against multi-resistant bacteria makes pentane-1,5-diol an interesting new compound for topical antimicrobial therapy in humans.

Administration, Cutaneous↗
PubMed2005

Combined metabolic gas analyser and dGPS analysis of performance in cross-country skiing.

The purpose of this study was to provide a more detailed analysis of performance in cross-country skiing by combining findings from a differential global positioning system (dGPS), metabolic gas measurements, speed in different sections of a ski-course and treadmill threshold data. Ten male skiers participated in a freestyle skiing field test (5.6 km), which was performed with dGPS and metabolic gas measurements. A treadmill running threshold test was also performed and the following parameters were derived: anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio = 1, onset of blood lactate accumulation and peak oxygen uptake (VO2peak). The combined dGPS and metabolic gas measurements made detailed analysis of performance possible. The strongest correlations between the treadmill data and final skiing field test time were for VO2peak (l x min(-1)), respiratory exchange ratio = 1 (l x min(-1)) and onset of blood lactate accumulation (l x min(-1)) (r = -0.644 to - 0.750). However, all treadmill test data displayed stronger associations with speed in different stretches of the course than with final time, which stresses the value of a detailed analysis of performance in cross-country skiing. Mean oxygen uptake (VO2) in a particular stretch in relation to speed in the same stretch displayed its strongest correlation coefficients in most stretches when VO2 was presented in units litres per minute, rather than when VO2 was normalized to body mass (ml x kg(-1) x min(-1) and ml x min(-1) x kg(-2/3)). This suggests that heavy cross-country skiers have an advantage over their lighter counterparts. In one steep uphill stretch, however, VO2 (ml x min(-1) x kg(-2/3)) displayed the strongest association with speed, suggesting that in steep uphill sections light skiers could have an advantage over heavier skiers.

Adolescent↗
PubMed2005

Advenella incenata gen. nov., sp. nov., a novel member of the Alcaligenaceae, isolated from various clinical samples.

A polyphasic taxonomic study of 14 isolates recovered from various human and veterinary clinical samples was performed. Phenotypically these isolates shared several characteristics with members of the Alcaligenaceae and related genera. Random amplified polymorphic DNA fingerprinting and whole-cell protein analysis suggested the presence of multiple genomic groups, which was confirmed by DNA-DNA hybridization experiments. 16S rRNA gene sequence analysis indicated that these isolates were related to the genera Pelistega, Taylorella, Oligella, Pigmentiphaga, Alcaligenes, Kerstersia, Achromobacter and Bordetella and belonged to the family Alcaligenaceae. Based on the results of the present study the organisms were classified in a novel genus, Advenella gen. nov. This genus comprises one named species, Advenella incenata sp. nov. (type strain LMG 22250T=CCUG 45225T) and five currently unnamed genomic species. The DNA G+C content of members of the novel genus Advenella is between 54.0 and 57.7 mol%.

Adolescent↗
PubMed2004

Inhibition of lipopolysaccharide-mediated human monocyte activation, in vitro, by alpha1-antitrypsin.

alpha1-Antitrypsin (AAT) is a major circulating and tissue inhibitor of serine proteinases. As such AAT is thought to play an important role in limiting host tissue injury at sites of inflammation. There is now increasing evidence, however, that AAT may exhibit biological activity independent of its protease inhibitor function. In this study we compared the effects of native (inhibitory) and modified (non-inhibitory), e.g., polymerised and oxidised forms of AAT on LPS-induced human monocyte activation, in vitro. We found that native AAT inhibited LPS-stimulated synthesis and release of TNFalpha and IL-1beta mRNA and protein, respectively, but enhanced the release of the anti-inflammatory cytokine, IL-10. Similarly, polymerised and oxidised forms of AAT inhibited LPS-stimulated IL-1beta and TNFalpha. The effects of AATs were observed whether added prior to or following removal of LPS, suggesting that sequestration of agonist was unlikely to explain their biological effects. Furthermore, studies with neutralising antibodies indicated that generation of IL-10 was unlikely to be the mechanism responsible for the inhibitory effects of AATs. Thus, our data demonstrate for the first time that AAT exhibits anti-inflammatory activity in vitro that is unrelated to inhibition of serine proteases.

Cells, Cultured↗
PubMed2004

The vulvar skin microenvironment: influence of different panty liners on temperature, pH and microflora.

The aim of this study was to confirm findings that vapour-impermeable panty liners might impair skin climate, and to assess their impact on the skin microflora. Temperature, surface pH and aerobic microflora were measured on vulvar skin of 102 women. The mean skin temperature was 1.1 degrees C higher when using a vapour-impermeable panty liner compared with not using one. Use of panty liners with vapour-permeable back sheets and acidic cores resulted in skin temperature, pH and microflora levels that were very close to those observed in persons not using liners. The temperature, pH and total number of microorganisms were significantly lower for users of vapour-permeable panty liners than for users of vapour-impermeable ones (p <0.05, p<0.001 and p<0.001, respectively). The microorganism densities were usually higher when using the vapour-impermeable panty liner, but mean differences were minor. The use of panty liners seems not to imply a microbial risk for normal, healthy women.

Adult↗
PubMed2003

Global positioning system and sport-specific testing.

Most physiological testing of athletes is performed in well-controlled situations in the laboratory. Multiple factors that are hard to control for have limited the use of sport-specific field testing. Recently, the technique of the differential global positioning system (dGPS) has been put forward as a way to monitor the position and speed of an athlete during outdoor activities with acceptable precision, thus controlling the two most important factors of performance in endurance athletics, i.e. inclination and speed. A detailed analysis of performance has been shown to be possible in combination with metabolic gas measurements. The combination of accelerometry and dGPS has also been shown to improve physiological field testing. The technique of dGPS could probably also be combined with other bio-measurements (e.g. electromyography and cycling cadence and power) and may enable other studies of exercise physiology in the field, otherwise restricted to the laboratory environment. This technique may also be of use in general exercise physiology where monitoring of patients with, for example, cardiovascular and pulmonary diseases, could be of interest for the future.

Acceleration↗
PubMed2002

Glutamine uptake by neurons: interaction of protons with system a transporters.

Astrocytes provide the glutamine required by neurons to synthesize glutamate and GABA. However, the mechanisms involved in glutamine transfer from glia to neurons have remained poorly understood. Recent work has implicated the System N transporter SN1 in the efflux of glutamine from astrocytes and the very closely related System A transporters SA1 and SA2 in glutamine uptake by neurons. To understand how these closely related proteins mediate flux in different directions, we have examined their ionic coupling. In contrast to the electroneutral exchange of H+ for Na+ and neutral amino acid catalyzed by SN1, we now show that SA1 and SA2 do not couple H+ movement to amino acid flux. As a result, SA1 and SA2 are electrogenic and do not mediate flux reversal as readily as SN1. Differences between System N and A transporters in coupling to H+ thus contribute to the delivery of glutamine from glia to neurons. Nonetheless, although they are not transported, H+ inhibit SA1 and SA2 by competing with Na+.

Amino Acid Transport System A↗
PubMed2002

Analysis of performance in orienteering with treadmill tests and physiological field tests using a differential global positioning system.

The aim of this study was to determine the physiological responses to orienteering by examining the interrelationships between the information provided by a differential global positioning system (dGPS) about an orienteer's route, speed and orienteering mistakes, portable metabolic gas analyser data during orienteering and data from incremental treadmill tests. Ten male orienteers completed a treadmill threshold test and a field test; the latter was performed on a 4.3 km course on mixed terrain with nine checkpoints. The anaerobic threshold, threshold of decompensated metabolic acidosis, respiratory exchange ratio, onset of blood lactate accumulation and peak oxygen uptake (VO2peak) were determined from the treadmill test. Time to complete the course, total distance covered, mean speed, distance and timing of orienteering mistakes, mean oxygen uptake, mean relative heart rate, mean respiratory exchange ratio and mean running economy were computed from the dGPS data and metabolic gas analyser data. Correlation analyses showed a relationship between a high anaerobic threshold and few orienteering mistakes (r = - 0.64, P < 0.05). A high threshold of decompensated metabolic acidosis and VO2peak were related to a fast overall time (r = -0.70 to -0.72, P < 0.05) and high running speed (r = 0.64 to 0.79, P < 0.05 and P < 0.01, respectively), and were thus the best predictors of performance.

Adult↗
PubMed1998

Assessment of the BacT/Alert blood culture system: rapid bacteremia diagnosis with loading throughout the 24 h.

OBJECTIVE: To determine blood culture (BC) diagnostic speed when combining an automated BC system with rapid loading of inoculated bottles throughout the 24 h. METHODS: A total of 111 positive BCs representing bacteremia were investigated in retrospect. All bottles were loaded into the BacT/Alert BC system (Organon Teknika) as soon as possible after sampling and time from specimen collection to Gram stain result was recorded. RESULTS: The mean time from specimen collection to loading was 3.5 h (median 2.1 h). We found that 74% of all positive BCs collected during daytime (08.00-16.00) were reported (as Gram stain) to the clinician before 17.00 the next day. For specimens collected between 16.00 and midnight the corresponding proportion was 67%. BCs drawn between midnight and 08.00 were reported before 17.00 the same day in 24% of the cases. CONCLUSIONS: Rapid loading of an automated BC system throughout the 24 h results in fast diagnosis of bacteremia. The diagnostic speed in this study represents a fair estimation of the maximal diagnostic speed accomplishable in a clinical situation with the BacT/Alert system in conjunction with normal daytime laboratory working hours.

Journal Article↗