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Biomedical subjects

I Johnson

Publications and source records attributed to I Johnson.

89 records · Page 5Linked to original sources
PubMed1977

Bakody sign.

Explore the source record for details and available documents.

Humans↗
PubMed1971

The oligosaccharide units of a human type L immunoglobulin M (Macroglobulin).

1. The carbohydrate composition of the monomeric unit of a type L macroglobulin (immunoglobulin M) was determined as 6 residues of fucose, 35 of mannose, 11 of galactose, 27 of N-acetylglucosamine and 9 of sialic acid. 2. Two types of oligosaccharide unit were present in the protein, one of which (Ca type) contained fucose, mannose, galactose, N-acetylglucosamine and sialic acid in the molar proportions 1:3-4:2:3-5:0-2, and the other (Cb type) contained mannose and N-acetylglucosamine in the proportions 6-8:2-3. 3. A tentative structure is proposed for the Cb type unit. 4. An S-carboxymethylcysteine-containing glycopeptide with a Ca-type unit was isolated after reduction, alkylation and tryptic digestion of the protein. 5. The immunoglobulin monomer appears to contain six oligosaccharide units of the Ca type and two of the Cb type.

Amino Acids↗
PubMedDate not supplied

Multiphoton confocal microscopy using a femtosecond Cr:forsterite laser.

With its output wavelength covering the infrared penetrating window of most biological tissues at 1,200-1,250 nm, the femtosecond Cr:forsterite laser shows high potential to serve as an excellent excitation source for the multiphoton fluorescence microscope. Its high output power, short optical pulse width, high stability, and low dispersion in fibers make it a perfect replacement for the currently widely used Ti:sapphire laser. In this paper, we study the capability of using a femtosecond Cr:forsterite laser in multiphoton scanning microscopy. We have performed the multiphoton excited photoluminescence spectrum measurement on several commonly used bioprobes using the 1,230 nm femtosecond pulses from a Cr:forsterite laser. Efficient fluorescence can be easily observed in these bioprobes through two-photon or three-photon excitation processes. These results will assist in the selection of dichroic beam splitter and band pass filters in a multiphoton microscopic system. We have also performed the autofluorescence spectrum measurement from chlorophylls in live leaves of the plant Arabidopsis thaliana excited by 1,230 nm femtosecond pulses from the Cr:forsterite laser. Bright luminescence from chlorophyll, centered at 673 and 728 nm, respectively, can be easily observed. Taking advantage of the bright two-photon photoluminescence from chlorophyll, we demonstrated the two-photon scanning paradermal and cross-sectional images of palisade mesophyll cells in live leaves of Arabidopsis thaliana.

Arabidopsis↗
PubMedDate not supplied

Correlates of condom use in the young adult population in Ontario.

OBJECTIVES AND METHODS: Data from the Ontario Health Survey were used to identify sociodemographic, lifestyle and sexual history characteristics associated with the use of condoms for protection against sexually transmitted diseases (STDs) in randomly selected adults between the ages of 16 and 44 years who had had two or more sexual partners in the 12 months before the survey (n = 2,699). RESULTS: Forty-two percent reported not having used condoms for protection against STDs. Those most likely to use condoms were 16 to 24 years of age, males, students, non-binge-drinkers, urban residents, and those at higher risk for HIV/AIDS. Of those who used condoms, 68% did not use them consistently. Individuals most likely to always use condoms were 16 to 24 years of age, males, students, non-binge-drinkers, and those with secondary school education. Age, gender, occupational activity, and non-binge-drinking were common correlates of both condom use and consistent use. CONCLUSIONS: Public health messages should be focused on people with multiple sex partners who are not using condoms for STD protection, including rural residents, those with high levels of education, and those over 34 years of age.

Adolescent↗