Search PubMed⌕ Search

Biomedical subjects

M L Smith

Publications and source records attributed to M L Smith.

At least 487 records · Page 27Linked to original sources
PubMed1967

Production of aflatoxin on wheat and oats: measurement with a recording densitometer.

A method has been developed for the production of aflatoxin by growing Aspergillus flavus NRRL 3145 on solid substrate wheat. Optimal yields of 900 mug of aflatoxin G(1) and 900 mug of aflatoxin B(1) per g of substrate were obtained in 4 to 5 days at 28 C. A study of aflatoxin production on hulls and groats of oats and on whole oats by A. flavus strains NRRL 2999, NRRL 3000, and NRRL 3145 revealed that aflatoxin was produced on all three substrates, although production was very slight on hulls. Strain NRRL 3145 grown on solid substrate groats produced the largest amounts of aflatoxin: 580 mug of B(1) and 450 mug of G(1) per g of substrate. A densitometric method for reading thin-layer chromatographic plates is described; this is more objective and more accurate than the visual methods previously used for the determination of all four aflatoxins.

Aflatoxins↗
PubMed1962

Production of Fumaric Acid in 20-Liter Fermentors.

The conditions necessary for the production of fumaric acid in 20-liter fermentors by fermentation of glucose with Rhizopus arrhizus strain NRRL 2582 were determined. Continuous neutralization of fumaric acid was necessary for optimal yields. Yields of the calcium salt were in excess of 65 g of fumaric acid from 100 g of sugar consumed during fermentation of sugar concentrations of 10 to 16%. Conditions established for calcium fumarate production include a simple mineral salts medium, 0.5 v:v:min aeration rate, 300 rev/min agitation rate in a baffled tank, 33 C incubation temperature, CaCO(3) to neutralize the acid formed, and a 4 to 5% (v/v) vegetative inoculum. A suitable procedure and medium for the preparation of a vigorous vegetative inoculum were established. The tendency for calcium fumarate fermentations to foam excessively was controlled with a proper antifoam agent added prior to sterilization of the medium and again at daily intervals during fermentation. The production of soluble sodium or potassium fumarates was inhibited when the concentration of fumarates reached 3.5 to 4.0%. No means of overcoming this inhibition was found. Starches and certain other grain-derived carbohydrates were fermented to form calcium fumarate in flask experiments with approximately the same efficiency as was glucose.

Journal Article↗
PubMedDate not supplied

The effect of freezing and storage on seminal immunoreactive prolactin.

Thirteen subjects were studied to compare changes in seminal immunoreactive prolactin produced by storage and freezing of semen and seminal plasma separated within 2 hours of ejaculation. Seminal prolactin was significantly higher in semen than in seminal plasma (paired t test, t = 3.29, p less than 0.005). The difference in prolactin between the two values correlated with sperm count (linear regression analysis, r = 0.65, p less than 0.02). This study suggested that variations in reported correlations between sperm count and seminal prolactin might be explained in part by the time interval of semen collection, centrifugation, and/or freezing.

Centrifugation↗
PubMedDate not supplied

3-D reconstruction of the cholinergic basal forebrain system in young and aged rats.

The 3-dimensional (3-D) distribution of cholinergic neurons located throughout the extent of the entire basal forebrain of young (4-5 months old) and aged (24-25 months old) Fischer-344 rats was examined using choline acetyltransferase immunocytochemistry (ChAT-IR). The number and 3-D position of ChAT-IR neurons spanning the basal forebrain were determined using serial sections and analyzed using computerized image analysis. The effects of aging on ChAT-IR neuron number were analyzed as a cohesive unit with respect to the classically-defined magnocellular subregions located within the basal forebrain (i.e., the medial septum, vertical and horizontal limbs of the diagonal band, and the nucleus basalis). Significant effects of age were found on ChAT-IR neuron number but no significant age-related interactions were noted with either the A-P, M-L, or D-V axes. These results suggest that a significant but diffuse age-related loss of ChAT-IR occurs along the entire length of the basal forebrain, and that this loss is not restricted to individual magnocellular nuclei (A-P axis), the M-L axis, or the D-V axis.

Aging↗
PubMedDate not supplied

Cognitive and motor development in children with vertically transmitted HIV infection.

This study was designed to examine mental and motor development in infants with vertically transmitted human immunodeficiency virus (HIV) infection. Early neurodevelopment was examined in 25 young children with HIV infection acquired through vertical transmission. Compared with 25 children born to HIV-positive mothers but not infected with the virus, and after controlling for developmental risk factors, the HIV-infected group showed impairments in mental and motor development. Mental and motor development were assessed using the Bayley Scales of Infant Development. On the mental scale (MDI), the HIV-infected infants obtained significantly lower scores than the uninfected infants. On the performace scale (PDI), the HIV-infected infants obtained significantly lower standard scores than the uninfected infants. CT scan results were available for 20 of the HIV-infected children. CT abnormalities were associated with developmental delays, particularly for motor development. The results point to the importance of early abnormalities in myelination and of subcortical lesions of cognitive and motor development.

Brain↗
PubMedDate not supplied

Diagnostic dilemmas in pediatric/adolescent dermatology: scaly scalp.

Scaly scalp is a common problem in the pediatric and adolescent population. The possible causes range from the commonly seen tinea capitis and seborrheic dermatitis to rare systemic diseases such as dermatomyositis and Letterer-Siwe disease. In all cases a thorough history and physical examination are important first steps to successful diagnosis and treatment.

Adolescent↗
PubMedDate not supplied

The immunoglobulin structure of human anti-M agglutinins.

Fifty examples of human anti-M agglutinins were subjected to reductive cleavage using both 2-mercaptoethanol (2-ME) and dithiothreitol (DTT). Thirty-nine (78%) were resistant to inactivation by sulphydryl compounds indicating IgG composition. This was confirmed by column chromatography. The remaining eleven sera were sensitive to reduction cleavage. There was no obvious association of immunoglobulin composition of the antibody with previous immune exposure to the M antigen. These results confirm observations in the literature that anti-M agglutinins are an exception to the generally expected correlation of saline agglutinating activity with IgM structure.

Agglutinins↗