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H Pettersson

Publications and source records attributed to H Pettersson.

At least 73 records · Page 4Linked to original sources
PubMed1994

Presentation and evaluation of a new optical sensor for respiratory rate monitoring.

A new optical sensor for respiratory rate monitoring was simultaneously compared with an acoustic sensor and a transthoracic impedance plethysmograph during normoventilation in the respiratory rate range of 9-17 breaths per minute. The response characteristics of the optical sensor were then measured during simulation of central apnoea and tachypnoea. Visual observation was chosen as the reference method for monitoring the respiratory rate. The measurements were performed in ten healthy volunteers and the respiratory signals recorded on an analogue tape and strip-chart recorder and analysed off-line. The response characteristics of the fibre optic sensor corresponded well with those of the acoustic sensor and impedance plethysmograph. All three methods responded rapidly to an apnoeic event.

Adult↗
PubMed1994

7-Hydroxycoumarin inhibits oncogene-induced transformation of murine fibroblasts.

7-Hydroxycoumarin (7-HC) is a naturally occurring substance with a variety of biological activities, e.g. antitumoral and immunomodulatory action. The potential mechanisms of 7-HC action on tumor cells have been investigated in a model of mouse fibroblasts transformed by distinct retroviral vectors carrying the oncogenes myc and ras. Treatment of the different oncogenic transformants with 7-HC in non-cytotoxic concentrations causes a strong inhibition of their proliferative capacity as measured by growth curves. Furthermore, incubation of the ras and myc transformants with 7-HC abrogated soft agar colony formation when compared to untreated cultures. These changes in cell growth characteristics of the various oncogene-transformed mouse fibroblasts were transient, since removal of 7-HC from the cultures caused a reappearance of the transformed properties of these cells within 6 days. The 7-HC-mediated inhibition of the proliferative capacity of the transformants was preceded by a selective down-regulation of oncogene expression. These data suggest that 7-HC causes a reversible inhibition of ras- and myc-induced neoplastic properties in transformed fibroblasts by selective down-regulation of retroviral RNA levels.

Animals↗
PubMed1994

A longitudinal study of orthopaedic outcomes for severe factor-VIII-deficient haemophiliacs. The Orthopaedic Outcome Study Group.

OBJECTIVE: Arthropathy is the major cause of morbidity in haemophilia. In an attempt to establish optimal therapeutic regimens for persons with haemophilia, we hypothesized that no direct relationship exists between increasing factor dosage and orthopaedic outcomes over time. DESIGN: A longitudinal uncontrolled 6 year study was carried out. Ankles, knees and elbows of patients were studied using physical and X-ray examination scores. Bleeding episodes and treatment regimens were determined. The amount of time lost from work and school, as well as days in hospital, was also monitored. SETTING: Twenty-one international haemophilia centres were used to accrue and follow patients over the 6 year period. SUBJECT: Severe (< 1%) factor VIII deficient patients under the age of 25 without inhibitors were recruited into the study. INTERVENTION: The status of the six major joints of these patients were measured annually for mobility. X-ray evaluation of these joints was carried out at the beginning and end of the study. Using a World Federation of Haemophilia joint and X-ray score, stability, progression or regression of arthropathy was evaluated. RESULTS: Physical and X-ray examination scores increased significantly with age, and the number of joint bleeds were significant in determining the delta score. Approximately 10% of patients entered with all six joints normal. Of these, 50% remained so. Year-long prophylaxis significantly reduced the rate at which joints deteriorate both on physical (P = 0.02) and X-ray examination (P = < 0.001). Patients on prophylaxis had significantly fewer days lost from work or school, as well as fewer days spent in hospital (P = < 0.01). CONCLUSIONS: Higher doses of factor per se do not necessarily produce improved orthopaedic outcomes. However, full time prophylaxis is likely to produce the best orthopaedic outcome. The most critical factor for a good orthopaedic outcome is the reduction of joint bleeds.

Factor VIII↗
PubMed1993

Diagnostic imaging.

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Diagnostic Imaging↗
PubMed1993

Generation of x rays for medical imaging by high-power lasers: preliminary results.

PURPOSE: To evaluate the use of x-ray imaging performed with a high-power laser system in biologic and medical studies. MATERIALS AND METHODS: A compact terawatt laser system based on chirped pulse amplification in titanium-doped sapphire was used. X rays were generated by irradiating a high-atomic-number target (tantalum). RESULTS: When photons with an energy below 10 keV were removed with use of 3 mm of aluminum, the half-value layer in aluminum for the remaining x rays was approximately 10 mm. The x-ray source allowed performance of biologic magnification radiography. Star-pattern tests indicated an equivalent focal spot size of less than 60 microns. Exposures of a single pulse could be obtained. The duration of a single x-ray pulse was estimated to be of the order of picoseconds. CONCLUSION: With use of subpicosecond laser pulses, x-ray generation can occur with a smaller equivalent focal spot size than with conventional x-ray sources.

Aluminum↗
PubMed1993

HLA-DR antigens, Gm allotypes and antiallotypes in early rheumatoid arthritis--their relation to disease progression.

OBJECTIVE: Evaluation of the prognostic value of immunogenetic markers in early rheumatoid arthritis (RA). METHODS: Ninety-nine patients with definite RA and disease duration 24 months or less were followed with standardized assessment. Disability was assessed by the HAQ index and radiographic changes in hands and feet by the Larsen method. The frequencies of HLA-DR genes were determined by serological typing, Gm allotype distribution by classical hemagglutination inhibition test, and occurrence of anti-Gm allotypes by use of anti-Rh coats. The immunogenetic findings were related to disease severity after 2 years' followup. RESULTS: Functional capacity was well preserved, disease activity was less, but radiographic changes in hands and feet had increased considerably at study finish. A group of 13 patients had developed rapidly progressive changes of hip and/or shoulder joints, all requiring arthroplasty. There was a significantly increased frequency of HLA-DR4. Twenty-seven of the 68 HLA-DR4 positive patients were putatively homozygous. HLA-DR4 was not related to disability or to severe small joint destruction. However, progressive large joint damage was significantly more prevalent in homozygous patients (p < 0.01). Gm allotype distribution was normal and not related to clinical findings. Anti-Gm antibodies were common and frequently specific for nonhost Gm allotype. Fifty-six patients carried anti-G1m(a), and occurrence of this antibody was significantly associated with radiographic progression of small joints (p = 0.01), presence of nodules (p < 0.01) and number of active joints (p = 0.001). CONCLUSION: Immunogenetic markers aided in identifying patients with early RA with more severe disease.

Adult↗
PubMed1992

Twenty-five years' experience of prophylactic treatment in severe haemophilia A and B.

In Sweden, prophylactic treatment of boys with severe haemophilia has been practised since 1958 in an attempt to convert the disease from a severe to a milder form. The present study population consisted of 60 severe haemophiliacs (52 A, 8 B), aged 3-32 years. Treatment is started when the boys are 1-2 years of age, the regimens used being 24-40 IU F VIII kg-1 three times weekly in haemophilia-A cases (i.e. greater than 2000 IU kg-1 annually) and 25-40 IU F IX kg-1 twice weekly in haemophilia-B cases. The orthopaedic and radiological joint scores (maximum scores of 90 and 78, respectively) are evaluated as recommended by the World Federation of Haemophilia. Of those subjects aged 3-17 years, 29 out of 35 individuals had joint scores of zero. The oldest group had only minor joint defects. The VIII:C and IX:C concentrations had usually not fallen below 1% of normal. All 60 patients are able to lead normal lives. In conclusion, it appears to be possible to prevent haemophilic arthropathy by giving effective continuous prophylaxis from an early age, and preventing the VIII:C or IX:C concentration from falling below 1% of normal.

Adolescent↗
PubMed1991

Diagnostic imaging.

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Diagnostic Imaging↗
PubMed1990

Early rheumatoid arthritis--onset, course, and outcome over 2 years.

Eighty-nine patients, 33 men and 56 women, with early definite rheumatoid arthritis were followed for 2 years. Two-thirds were seropositive. About 1/3 were eventually treated with second line drugs. The disease mostly had an insidious onset initially involving the finger joints. Early remission occurred in 16%. Patient relevant measures such as pain, patient's overall assessment of disease activity and anxiety decreased significantly. Disability evaluated by the HAQ disability index remained at a low level. The joint damage score (JDS) in hands and feet increased steadily and only 18% were nonerosive after 2 years. One-third developed hand deformities which was associated with higher JDS. A joint function index (SOFI) correlated significantly with JDS. Twenty-eight percent had a slower rate of joint damage progression the second year. There was no significant correlation between JDS and disease duration. Six patients developed rapidly progressive damage in larger joints, five in the hip joints and one in the shoulder joint, all requiring joint replacement. The ability to predict outcomes with clinical and laboratory variable obtained at entry was of limited clinical usefulness. By applying discriminant analyses 67%-80% of the cases who fared worst regarding clinical, functional, and radiological features could be correctly classified.

Adult↗
PubMed1990

Disease activity and joint damage progression in early rheumatoid arthritis: relation to IgG, IgA, and IgM rheumatoid factor.

The clinical and biochemical correlations with joint damage progression over two years in a consecutive group of 68 patients with rheumatoid arthritis with disease duration of less than two years are reported. Joint damage was assessed with Larsen's severity scale and a measure of change in progression rate constructed. Initial haemoglobin concentration, Ritchie index, and Waaler-Rose titre in combination accounted for one third of the variance in joint damage progression. Rheumatoid factor (RF) concentrations were followed with enzyme linked immunosorbent assays (ELISAs) for IgG RF, IgA RF, and IgM RF. The RF concentrations, except IgG RF, decreased with time; significant correlations between RFs and disease activity were few and barely clinically useful. After two years IgG RF correlated significantly with a radiological score if early non-erosive changes were omitted. All RFs tended to correlate better with this radiological score at all three observation points. Analyses of the change in progression rate indicated a time delay between development of radiographic changes and increase of IgG RF. These results suggest an indirect relation between RFs and joint damage. Clinical and biochemical improvements in early RA occur despite joint damage progression, and conventional markers have insufficient predictive value.

Arthritis, Rheumatoid↗