Biomedical subjects

J Lamotte

Publications and source records attributed to J Lamotte.

11 recordsLinked to original sources

PubMed2001

The power output of laser pointers: do they exceed federal standards?

BACKGROUND: Concern about the safety of laser pointers has increased as these devices have become readily available to the public, which includes children who may use them improperly. According to federal (Food and Drug Administration) standards, laser pointers are class 3a devices, and power output cannot exceed 5.0 mW. METHODS: We tested a sample consisting of 29 red diode laser pointers obtained from various sources that were equipped with fresh batteries. Power output was measured with an optical power meter with the sensor 5.0 cm from the laser. The laser was turned on for 60 s and a reading was taken every 10 s. This procedure was repeated five times for every laser. RESULTS: The power output of unaltered lasers ranged from 0.7 mW to a high of 3.9 mW. Alterations to some of the lasers increased the output slightly above 5.0 mW. CONCLUSIONS: When the laser pointers in our sample were used as packaged, they did not exceed the federal standards of 5.0 mW.

Consumer Product Safety↗

PubMed1996

Structure of the low-affinity penicillin-binding protein 5 PBP5fm in wild-type and highly penicillin-resistant strains of Enterococcus faecium.

Among its penicillin-binding proteins (PBPs), Enterococcus faecium possesses a low-affinity PBP5, PBP5fm, which is the main target involved in beta-lactam resistance. A 7.7-kb EcoRI chromosomal fragment of E. faecium D63r containing the pbp5fm gene was cloned and sequenced. Two open reading frames (ORFs) were found. A 2,037-bp ORF encoded the deduced 73.8-kDa PBP5fm, the amino acid sequences of which were, respectively, 99.8, 78.5, and 62% homologous to those of the low-affinity plasmid-encoded PBP3r of Enterococcus hirae S185r and the chromosome-encoded PBP5 of E. hirae R40 and Enterococcus faecalis 56R. A second 597-bp ORF, designated psrfm, was found 2.3 kb upstream of pbp5fm. It appeared to be 285 bp shorter than and 74% homologous with the regulatory gene psr of E. hirae ATCC 9790. Different clinical isolates of E. faecium, for which a wide range of benzylpenicillin MICs were observed, showed that the increases in MICs were related to two mechanisms. For some strains of intermediate resistance (MICs of 16 to 64 micrograms/ml), the increased level of resistance could be explained by the presence of larger quantities of PBP5fm which had an affinity for benzylpenicillin (second-order rate constant of protein acylation [k+2/K] values of 17 to 25 M(-1) s(-1)) that remained unchanged. For the two most highly resistant strains, EFM-1 (MIC, 90 micrograms/ml) and H80721 (MIC, 512 micrograms/ml), the resistance was related to different amino acid substitutions yielding very-low-affinity PBP5fm variants (k+2/K < or = 1.5 M(-1) s(-1)) which were synthesized in small quantities. More specifically, it appeared, with a three-dimensional model of the C-terminal domain of PBP5fm, that the substitutions of Met-485, located in the third position after the conserved SDN triad, by Thr in EFM-1 and by Ala in H80721 were the most likely cause of the decreasing affinity of PBP5fm observed in these strains.

Amino Acid Sequence↗

PubMed1993

[Post-traumatic coxarthrosis. Medicolegal conditions of the likelihood of fractures, luxations or contusions].

Trauma is the cause of 5 to 10% of all cases of osteoarthritis of the hip. One third of patients with a dislocation or fracture-dislocation of the hip or an acetabular fracture develop osteoarthritis of the hip within one to 20 years. Symptoms may be minor or absent during the interval. In addition to severe injuries, simple contusions resulting for instance from a blow to the greater trochanter or knee or from forced abduction of the hip (e.g., splits) can also result in osteoarthritis of the hip. We developed a set of five imputability criteria, of which three are essential: 1) documentation of the exact nature of the trauma; 2) absence of osteoarthritis in the uninjured hip; 3) consistency between the estimated duration of osteoarthritis and the date of the injury. Causality assessment problems which arise when a trauma worsens or accelerates preexisting osteoarthritis are discussed on the basis of clinical and roentgenographic findings. Mechanical and biochemical factors involved in the pathophysiology of contusion-related osteoarthritis of the hip are briefly reviewed.

Adolescent↗

PubMed1993

[Quality of life and functional indices in osteoarthritis].

The main Indices of Quality of Life used in rheumatology and their aims and applications are surveyed. Their use in osteoarthritis implies a few issues that are addressed in a critical manner. Indices of Quality of Life are useful to measure deficiency resulting from osteoarthritis by comparison with other rheumatic diseases, as rheumatoid arthritis, connective tissue diseases, fibromyalgia... They are sensitive enough for apraising the domains improved by a radical treatment such as joint replacement. However, their scores are only slightly changing in most of the drug trials, in which the more simple functional indices seem demonstrative enough. Last but no least, they are notably time consuming for both the patient and the physician.

Activities of Daily Living↗

PubMed1988

[Ambulatory assessment of chronic bronchitis using a computerized questionnaire and pneumotachography with or without interruption of the air supply].

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Adult↗

PubMed1985

[Non-arthrosic geodes in the femur head. Isolated or predominant geodes].

The isolated or predominant geodes of the femoral head without signs of coxarthritis or coxitis, seem to form in response to: osteochondritis dissecans in 9 cases where the sequester was only visible in profile films or oblique images for 5 cases, and only at time of operation in 2 cases; incipient necrosis in 3 adult cases, not evidenced in frontal films and only seen in profile films with the patient under axial traction; femoral head dysmorphia in 6 cases among which were 4 polyepiphyseal dysplasias and 2 coxa plana without radiographically apparent sequesters; induced increased pressure caused by congenital subluxation or a major disorder of posture and locomotion of lower limbs in 3 cases. In 2 cases no classification could be assigned to isolated or predominant geodes of the femoral head in spite of anatomic examination. The diagnosis of these isolated or predominant geodes of the head of the femur necessitates excellent films made from different angles of view (profile, "false" profile, usual profile, sometimes oblique shots, tomograms) and often enough a biopsy which must be obtained directly through the joint, not transcervically through the neck if a reliable specimen is desired. The surgical treatment indicated is voiding and packing to a maximum the geodes possibly correcting the former increased pressure discordance. But, in lots of cases the intensity of pain and discomfort remains moderate for years, so indication for surgery arises late after onset.

Adolescent↗

PubMed1983