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Biomedical subjects

D M Lewis

Publications and source records attributed to D M Lewis.

At least 145 records · Page 8Linked to original sources
PubMed1976

Induction of fibrogenesis by lung antibody-treated macrophages.

Using a modification of an in vitro model of fibrogenesis, lung connective tissue antibodies have been shown to stimulate macrophages to release a collagen stimulating factor acting on fibroblast target cells. This stimulation was measured by increased hydroxyproline production from fibroblasts that had reached stationary growth phase. In subcytotoxic amounts, this antibody had no such effect directly on fibroblasts. These findings further illustrate the value of studying fibrogenesis by the in vitro method.

Animals↗
PubMed1976

Isolation and partial characterization of a major basic protein from rat eosinophil granules.

The rat eosinophil granule possesses a major basic protein (MBP) similar to that previously isolated from human and guinea pig eosinophils. This conclusion is based on demonstration that the major protein of the rat eosinophil granule is a low molecular weight, highly basic material with an amino acid composition similar to that of the human and guinea pig MBP.

Amino Acids↗
PubMed1975

Further studies on the effect of lung antibodies on the pathogenesis of tuberculosis.

A study was made to further clarify the role of lung reactive antibodies in tuberculous infection. Following intravenous infection with viable tubercle bacilli, mice received mouse anti-mouse lung antibodies for three weeks. Control groups consisted of tuberculous mice receiving non-lung antibody containing fluid and uninfected mice. A method was developed for quantitating tuberculous infection in these different groups by expressing the number of lesions produced per unit of cross-sectional surface area of the lung. Passive administration of lung antibodies was found to significantly potentiate the number of tuberculous lesions. It was concluded that the antibody in some way lowered the resistance of the tissue to invasion.

Animals↗
PubMed1974

The properties of motor units in a fast and a slow twitch muscle during post-natal development in the kitten.

1. Motor units were functionally isolated from a fast and a slow twitch muscle of kittens: flexor digitorum longus (FDL) and soleus. Both muscles were examined in two groups: one aged about 2 weeks and the other 6 weeks.2. A clear division into alpha and gamma axons could be made. The mean conduction velocity of alpha axons from FDL was higher than that of soleus axons at both ages.3. Tetanic tensions were expressed as a percentage of whole muscle tension. The distributions of motor unit tensions were symmetrical in soleus muscles but were skewed towards large values in FDL. In both types of muscle the scatter of motor unit tensions was greater at 2 weeks than at 6, the mean percentage tension also fell with age.4. The motor unit twitch times to peak were symmetrically distributed in soleus but skewed towards large values in FDL. The variance was less than in adults.5. Motor unit axonal conduction velocity was related to tetanic tension and twitch speed. The relationship between twitch time to peak and the ratio of twitch to tetanic tension varied with age but was not seen so clearly.

Action Potentials↗
PubMed1974

Isometric contractions of motor units in self-reinnervated fast and slow twitch muscles of the cat.

1. Isometric contractions of motor units have been studied in self-reinnervated soleus and flexor digitorum longus muscles, the motor nerves of which had been transected 6 months earlier.2. The distributions of motor unit tetanic tensions in both muscles were skewed towards large values and showed greater variance than normal: there were motor units which produced more tension and others which developed less tension than in control muscles. Mean tensions of motor units are compared with those of the controls.3. The variance of times to peak of motor units in both muscles was significantly smaller than normal.4. Conduction velocities of axons were slower than normal above the point of nerve section. A number of axons did not functionally cross this point and those that did conducted slowly below the neuroma.5. Many of the correlations seen in normal muscle between axon conduction velocity, motor unit tetanic tension, twitch time to peak and ratio of twitch to tetanic tension were demonstrated in reinnervated muscle.6. We suggest that the pattern of motor unit organization in self-reinnervated muscle can in part be due to random regrowth of axons but is largely produced by specific processes related to axon size which are not identical in fast and slow muscle.

Animals↗