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Biomedical subjects

H C Ford

Publications and source records attributed to H C Ford.

At least 55 records · Page 3Linked to original sources
PubMed1987

Double-label two-dimensional electrophoresis of serum and plasma proteins from patients with multiple sclerosis.

A double-label two-dimensional electrophoretic procedure has been used to search for abnormal proteins in the serum and plasma of patients with definite multiple sclerosis. The procedure possesses high resolving power and is particularly valuable in comparative studies of complex mixtures of proteins since differences due to gel-to-gel variations in protein mobilities are eliminated. Proteins present in serum and plasma at a concentration of 5-10 micrograms/ml are detected routinely. No consistent differences were observed between patients with multiple sclerosis and normal subjects in comparisons using pooled or individual specimens of serum or plasma. The absence of consistent differences in serum and plasma proteins between normal subjects and MS patients applied even when the sensitivity of the procedure was increased several-fold and when the possibly obscuring effect of albumin in the electrophoretic gels was eliminated. To our knowledge, this study combines the most extensive and sensitive search for consistent abnormalities in serum and plasma proteins in multiple sclerosis sera thus far reported.

Autoradiography↗
PubMed1987

Multiple sclerosis: a survey of alternative hypotheses concerning aetiology, pathogenesis and predisposing factors.

There is abundant evidence that both environmental and genetic factors play a role in the aetiology and pathogenesis of multiple sclerosis. Currently, a virus infection and an abnormality of T-cell function are favoured candidates for the environmental and genetic factors, respectively. However, as long as convincing evidence for a specific viral infection and for a pathogenetic role for T-cells in multiple sclerosis is lacking, it may be worthwhile to consider alternative hypotheses that have been proposed in recent years. These have been classified in this review under the headings Toxins, Dietary and Metabolic Abnormalities, Embolism, Infection, and Immunological Mechanisms.

Diet↗
PubMed1986

A double-label two-dimensional gel electrophoresis procedure specifically designed for serum or plasma protein analysis.

A double-label two-dimensional electrophoresis procedure has been developed which is specifically designed for the comparison of serum or plasma proteins in two different samples. Proteins are labeled by reductive methylation with [14C]- or [3H] formaldehyde. The procedure is economical because small quantities of relatively inexpensive isotopes are used and it is at least as sensitive as silver staining in detecting proteins. A fourfold increase in the sensitivity of autoradiography over existing methods was obtained by performing autoradiography before processing the gel for fluorography. A spot in the electrophoretic gel that contains 17-28 ng of labeled protein is detectable. This corresponds to proteins present in serum at a concentration of 5-10 micrograms/ml. Even greater sensitivity can be achieved, at greater expense, by increasing the quantities of the radioisotopes in the labeling reaction. The particular value of the double label approach is that complex mixtures from two different sources are resolved together thus eliminating the possibility of differences arising from the resolving procedure itself. The procedure was applied to a mixture of serum and plasma from a single subject and a number of qualitative and quantitative differences were observed.

Autoradiography↗
PubMed1986

The effect of substrate and epidermal growth factor on human placental trophoblast cells in culture.

Attempts were made to select for trophoblast cells in cultures of mixed cell populations derived from preterm (7 to 12 wk) or term human placentas. Epidermal growth factor added to cultures on solid or porous supports caused proliferation of epithelial-type cells to give a confluent monolayer but did not increase the expression of differentiated function. The presence or absence of placental basement membrane collagen as substrate made little apparent difference; however a porous basement membrane collagen support led to increased differentiated function. Initial production of human chorionic gonadotrophin was increased and after 4 wk in culture a substantial proportion of the cells exhibited alkaline phosphatase activity. Epidermal growth factor and a substrate of placental basement membrane collagen on a porous support favorably influence the growth and differentiation of human trophoblast cells in culture.

Cell Cycle↗
PubMed1986

Intracellular binding proteins for retinol and retinoic acid in early and term human placentas.

Specific binding of both [3H]retinol and [3H]retinoic acid was observed in the cytosol fraction from term placentas and specific binding of [3H]retinol but not [3H]retinoic acid was detected in the cytosol fraction from placentas of 8-12 week pregnancies. The elution volume of the bound radioactivity on Sephadex G-100 column chromatography was within the range expected for proteins of molecular weight 14 500, in agreement with the results of others for cellular retinol- and retinoic acid-binding proteins from other tissues. The role of these proteins in mediating the effects of vitamin A on growth and differentiation of the placenta and fetus has yet to be determined.

Carrier Proteins↗
PubMed1985

Abnormalities of serum and plasma components in patients with multiple sclerosis.

Qualitative and quantitative abnormalities in protein and non-protein components of serum and plasma in patients with multiple sclerosis have been the subjects of numerous reports. In this review many of the more recent observations are documented and evaluated. It is concluded that at present the welter of information that has been gathered does not contribute in any major, coherent way to our understanding of the etiology or pathogenesis of the disorder. Several of the abnormalities that have been observed may be future candidates for biochemical markers for multiple sclerosis; at present none is sufficiently reliable, distinctive or easily performed to warrant the status of a useful diagnostic or prognostic test.

Amino Acids↗
PubMed1984

Human placental microvilli contain high-affinity binding sites for folate.

Uptake of [3H]pteroylglutamic acid [( 3H]PteGlu) was studied in microvilli isolated from the syncytiotrophoblast of the human term placenta. The effect of changes in medium osmolality on the equilibrium uptake of [3H]PteGlu was negligible, which suggested that the observed uptake represented binding to proteins on or within the microvilli rather than translocation of the vitamin from the incubation medium to a free state in the intravesicular fluid. Equilibrium uptake experiments performed over a wide range of [3H]PteGlu concentrations disclosed a class of binding sites with an association constant of 0.3 nM-1 as well as a second class of sites with high capacity and low affinity. Binding of [3H]PteGlu at the high-affinity sites was inhibited by tetrahydrofolate and N5-methyltetrahydrofolate, but not by several other structural analogues. It is likely that the high-affinity binding sites are receptors for maternal plasma folate; however, their role in placental transport or storage of the vitamin was not delineated in these studies.

Aminoisobutyric Acids↗
PubMed1982

Is Percoll innocuous to cells?

Peritoneal macrophages from mice, isolated rat liver Kupffer cells and rat testis Leydig cells ingested large numbers of Percoll particles, a gradient medium widely used for separation of cells and subcellular organelles by density-gradient centrifugation. A decrease in the percentage of macrophages adhering to plastic also occurred after exposure of the cells to Percoll, even at 4 degrees C, a temperature at which Percoll was not ingested. The effect of Percoll on macrophage adherence may involve a loose association between the density medium and the cell surface. Other cell-surface-related phenomena may also be affected by prior exposure of cells to Percoll.

Animals↗
PubMed1982

Isolation of rat Leydig cells by density gradient centrifugation.

A rapid method for preparing Leydig cells from rat testes is described. An interstitial cell suspension, prepared by collagenase treatment of decapsulated testes, was centrifugal for 10 min over a cushion of 60% (v/v) Percoll to remove red blood cells, and then centrifuged for 20 min in a 0-60% linear density gradient of Percoll. Seventy-four per cent of the cells present in that fraction of the gradient comprising 35-50% Percoll were Leydig cells; the yield from each testis was about 1.5 x 10(6) cells. The Leydig cells appeared viable, excluded Trypan blue, possessed high-affinity binding sites for human chorionic gonadotrophin (hCG) and synthesized increased quantities of testosterone in response to hCG. The cells could be stored overnight in 20% (v/v) glycerol at -20 degrees C, with only minimal effect on the specific activities of a number of enzymes used as markers of subcellular components. Testosterone production in vitro by the cells after storage for 20 h was greater than that of hCG-stimulated fresh cells and was not further increased by hCG.

Animals↗
PubMed1981

The electrophoretic demonstration of unique oligoclonal immunoglobulins in cerebrospinal fluid as a diagnostic test for multiple sclerosis.

Polyacrylamide disc gel electrophoresis was performed on unconcentrated cerebrospinal fluid and serum from 132 neurological patients and from 33 patients without neurological disease. The presence of unique, discrete immunoglobulin bands in the gamma-globulin (cathodal) region of the cerebrospinal fluid gel was assessed as a diagnostic test for multiple sclerosis. The procedure exhibited a specificity for multiple sclerosis of 94% and a sensitivity of 72%, and is easier to perform than most of the other published procedures used to demonstrate oligoclonal immunoglobulins in cerebrospinal fluid. It is recommended for use in the clinical chemistry laboratory as a valuable adjunct to the diagnosis of multiple sclerosis.

Humans↗
PubMed1981

Microvilli of the human term placenta. Isolation and subfractionation by centrifugation in sucrose density gradients.

Human placental microvilli were isolated and separated into two fractions by centrifugation in sucrose density gradients. Electron-microscopic morphology and morphometry, the distribution of enzymic activities and the results of sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of proteins were used to assess the purity of the final preparations and to define their properties. The combined evidence strongly suggested that the preparations contained negligible material that was not plasma membrane. The two fractions of microvilli differed in buoyant density, protein composition, enzyme specific activities and microscopic appearance. Some of these differences were explained by the absence of internal structure in the microvilli of the lighter fraction.

Cell Fractionation↗
PubMed1981

Correlation of primary breast cancer histopathology and estrogen receptor content.

We studied the association of estrogen receptor (ER) with several histologic variables that correlate with breast tumor differentiation and with patient prognosis. Contingency table analysis revealed highly statistically significant correlations between ER content and histologic and nuclear grades, tumor necrosis, and the degree of elastosis and lymphoid cell infiltration. ER positive tumors were more likely than ER negative tumors to demonstrate histological evidence of tumor differentiation. All tumors with histologic grade 1 or nuclear grade 1 (best differentiated) were ER positive or borderline positive. Eighty-nine percent of ER negative tumors were histologic grade 3 and 78.4% were nuclear grade 3 (poor differentiation). ER positive tumors were also correlated with absent tumor necrosis, higher elastic content, and absent lymphoid cell infiltration, all features of good differentiation. Medullary carcinomas were frequently (73%) ER negative, but no relationship between ER and other morphologic types of breast cancer or 9 other morphologic variables was found. ER appears to be a biochemical marker for the degree of differentiation of human breast cancer providing a rationale for the observed differences in biological behavior between receptor positive and negative tumors.

Axilla↗
PubMed1980

Multiple myeloma with an IgD kappa monoclonal protein.

The case of a female patient with multiple myeloma in whom the circulating monoclonal protein was IgD with kappa light chains is presented. The case is extremely unusual and serves to emphasize how little is known about the function, metabolism, and regulation of immunoglobulin D.

Bone Neoplasms↗