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Biomedical subjects

M C Brown

Publications and source records attributed to M C Brown.

At least 199 records · Page 11Linked to original sources
PubMed1979

Schistosoma mansoni: ultrasonically detectable motor activity responses to 5-hydroxytryptamine in vitro.

The ultrasonic method compared favourably with other methods for monitoring schistosome motor activity in vitro, being able to detect and differentiate between the activity responses of Schistosoma mansoni to 5-hydroxytryptamine at concentrations down to 1 X (10(-6) M. This was taken to indicate suitable sensitivity for the application of the ultrasonic method to other drug studies.

5-Hydroxytryptophan↗
PubMed1979

Evaluation of an automated blood pressure measuring device intended for general public use.

Responding to Chicago newspaper reports, measurements of blood pressure by a publicly available, automated coin-operated device were compared with those of human observers using the standard cuff and auscultatory technique. One machine was examined in the laboratory, and eight others at randomly selected sites. Analysis of readings made on 100 persons in the laboratory and 227 in the field led to the following conclusions: 1) On the average, the machines measured fifth phase diastolic blood pressure at nearly the same level as did human observers; 2) The machines were more variable measuring systolic blood pressure with four differing from the average human reading by 1mm Hg or less, but two differing by 8mm Hg or more; 3) The agreement between machine-human pairs of readings was not as good as between human-human pairs, but the differences in level of agreement--both in determining the actual value and in categorizing the values as normal, borderline, or high--were small and have little practical importance; 4) Linear regression analyses of the relationship between simultaneously determined machine and human readings indicated that the average human-machine difference was the same over the range of pressures tested. Publicly available blood pressure measuring devices should be labeled concerning their purposes, capabilities, and limitations. Rules and regulations governing their use in the City of Chicago are being prepared by this city's Legal Department.

Blood Pressure Determination↗
PubMed1979

Loss of strain specificity of the TA3-St subline: evidence for the role of epiglycanin in mouse allogeneic tumor growth.

We described the in vivo conversion of the strain-specific ascites murine mammary adenocarcinoma subline TA3-St to a new ascites subline designated TA3-MM. This conversion occurred during passage in a syngeneic A/HeHa mouse infected with pneumonia-producing microorganisms. The mode number of chromosomes of the TA3-MM cell (82) was greater than that of the parental TA3-St cell (69) or the other non-strain-specific subline TA3-Ha (42). The TA3-MM subline could grow in and kill mice of various allogeneic strains. In addition, the TA3-MM cell possessed numerous receptors for the lectin of Vicia graminea seeds, which were hardly detectable at the surface of the parent TA3-St subline but were present in abundance at the cell surface of the non-strain-specific subline TA3-Ha. These lectin receptors of the TA3-Ha cell were previously demonstrated to be present in a unique high-molecular-weight endogenous cell surface glycoprotein termed epiglycanin. The V. gramines lectin receptors on the new TA3-MM subline also were present on an epiglycanin-like molecule. This finding provides further evidence for the hypothesis that allogeneic growth in the TA3 system is a direct result of these membrane glycoproteins.

Adenocarcinoma↗
PubMed1979

Isolation and partial characterization of an epiglycanin-like glycoprotein from a new non-strain-specific subline of TA3 murine mammary adenocarcinoma.

A new non-strain-specific ascites subline of the TA3 mammary adenocarcinoma TA3-MM, which arose in vivo from the strain-specific TA3-St subline during an acute respiratory illness of the syngeneic mouse strain A/HeHa hosts, possessed at its surface a glycoprotein not found on the parent TA3-St cell. This glycoprotein, termed TA3-MM epiglycanin, was characterized by a high molecular weight (500,000), by potent inhibition of hemagglutination by the Vicia gramines lectin, and by carbohydrate and amino acid compositions nearly identical to those of the glycoprotein epiglycanin present at the surface of the allotransplantable TA3-Ha ascites cell. By electron microscopic examination, TA3-MM epiglycanin appeared as long extended rods with widths (2.5 nm) and lengths (450--500 nm) similar to those of TA3-Ha epiglycanin. Incubation of each of two sublines of the TA3-MM ascites cell, TA3-MM/1 and TA3-MM/2, with a modified trypsin followed by column chromatography produced approximately 1.0- and 0.2-fold as much epiglycanin-like material, respectively, as was obtained from the TA3--a ascites cell. Continuous growth of the TA3-MM cell in suspension culture resulted in an almost complete disappearance of epiglycanin in a manner demonstrated earlier for the TA3-Ha cell grown under similar conditions. Allotransplantability in the TA3-MM cell may be due, at least in part, to masking a histocompatibility antigens by epiglycanin-like molecules.

Amino Acids↗
PubMed1978

Further studies on the relationship between large glycoprotein molecules and allotransplantability in the TA3 tumor of the mouse: studies on segregating TA3-HA hybrids.

In a series of six TA3-HA/A.CA hybrid cell lines formed by the fusion of the TA3-HA mammary carcinoma of a strain A mouse with a normal embryonic fibroblast of an A.CA mouse and then converted to the ascites form in parental strain A, the capacity to grow in foreign strains was inversely related to the ability to absorb anti-H-2a antibody. The absorptive capacities of the hybrid cell lines were intermediate between the low absorptive capacity of the non-strain-specific parent TA3-HA ascites cell line and the much higher absorptive capacity of the strain-specific ascites line TA3-St of the same tumor. Each hybrid cell line possessed an abundance of large endogenous cell-surface glycoprotein molecules similar to epiglycanin, a glycoprotein detected at the surface of the parent TA3-HA cell. The results suggested that the amount of epiglycanin-like material at the hybrid cell surfaces, determined by chemical and immunochemical methods, may have been directly related to the capacities of the cells to grow in foreign mouse strains and inversely related to their capacities to absorb anti-H-2a antibody.

Animals↗
PubMed1978

Sprouting and regression of neuromuscular synapses in partially denervated mammalian muscles.

1. The capacity of motor units to sprout after partial denervation and the ability of regenerating axons to suppress newly formed sprouts was examined in mouse skeletal muscle. Most experiments were performed on the peroneus tertius muscle which has 300 muscle fibres and eleven motor units ranging in strength from 1 to 35% of the total muscle tension. 2. Individual units, regardless of starting size, were able to sprout by up to 5 times their normal size following interruption of one of the two spinal roots innervating the muscle. In practive this resulted in muscles which had three or more units left intact becoming completely innervated again within 12 days. The majority of the sprouts probably innervated the old denervated end-plate sites. In the absence of re-innervation by the severed motor axons the sprouts persisted. In peroneus tertius about 60% of the sprouts giving rise to end-plates arose terminally and 40% collaterally. In soleus almost all the sprouts were terminal. 3. Re-innervation of the muscle by the severed motor axons occurred, starting from 14 days onwards after a crush injury, 19 days onwards after a cut. Re-innervation occurred even in muscles which presumably had no remaining denervated muscle fibres at the time regenerating axons reached the muscle. The re-innervating fibres grew to the original end-plate sites. 4. Following re-innervation the size of sprouted motor units apparently decreased. Thus, after re-innervation of muscles with three or more sprouted motor units, the sprouted units no longer caused contraction of all the muscle. However, the normal state of the muscle was not restored and the sprouted units continued to innervate more muscle fibres than normal, returning axons less than normal, and a small percentage of muscle fibres (ca. 10%) remained functionally innervated by axons of both sorts. 5. It is concluded that (i) in the mouse, axonal sprouting is a rapid and efficient process for restoring innervation; (ii) re-innervation of already innervated fibres can occur if the regenerating axons can return to existing end-plate sites; (iii) some of the redundant innervation is removed or repressed. 6. Possible mechanisms of competition between axon terminals are considered.

Animals↗
PubMed1978

Thyroid gland volume estimated by use of ultrasound in addition to scintigraphy.

The method of estimating the mass of the thyroid gland from the area of the scintigraphic image has been compared with a method combining ultrasonic with scintigraphic images. The results for both methods were compared with surgical findings, and the scintiscan method alone was found to produce estimates which were on an average 79.5% of the surgical results. The corresponding estimates for the combined method were, on average, 100.4%.

Humans↗