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Biomedical subjects

F Miller

Publications and source records attributed to F Miller.

At least 235 records · Page 13Linked to original sources
PubMed1977

Serum-derived immunosuppressive substances. II. An evaluation of various sources for an endogenous regulator of lymphocyte activation.

Four published methods (ion-exchange chromatography, heat, molecular sieving and alcohol fractionation) for the preparation of fractions of normal sera and tissues which possess immunosuppressive activity are compared. Human and bovine serum and human, bovine and ovine tissues including spleen, placenta and thymus were investigated as sources of substances which were immunosuppressive when added to mixed lymphocyte cultures and when injected into mice 24 h before antigenic challenge. Cohn fraction IV of human serum purified by ion-exchange chromatography at pH 5 was the most convenient preparation examined. The problems of establishing the nature of or the identity between substances being studied in different laboratories are discussed and the recommendation is made that a standard assay for activity be adopted.

Animals↗
PubMed1977

Serum-derived immunosuppressive substances. III. Regulation of the immune response by human serum alpha-globulin fractions: the dose-response relationship.

Suppression of the plaque-forming cell response in mice following injection of substances fractionated from pooled normal serum alpha-globulin was investigated. The dose-response relationship for fractions obtained by ion-exchange chromatography show that a single preparation has both enhancing and suppressive activities which are revealed at different doses. Whether this observation reflects the sum of activities of a number of molecular species remains to be determined. The immune responses to both thymus-dependent (heterologous erythrocytes) and thymus-independent (DNP-ficoll) antigens are suppressed while the response to the thymus-independent antigen lipopolysaccharide is enhanced. Thus, the cellular locus for immunosuppression cannot be exclusively on the T cell, and the magnitude of the action of the two populations (T and B cells) remains unclear.

Alpha-Globulins↗
PubMed1976

SV 40 related papova-viruses in human meningiomas.

Human meningiomas show characteristic chromosome aberrations very similar to those reported in human cell cultures experimentally transformed by Simian virus 40 (SV 40). Three out of eight meningiomas tested showed SV 40 specific tumor antigen but no virus capsid antigen. Experiments to rescue virus were successfully performed. Electron microscopic studies of these cell cultures revealed cytoplasmic inclusions containing virus particles which corresponded in size and morphology to Papova viruses.

Antigens, Viral↗
PubMed1976

Preparation of conjugated erythrocytes for long term use in hemolytic plaque assays, complement fixation studies, or passive hemagglutinations: a comparative study of several methods.

A variety of conjugation procedures, with and without glutaraldehyde stabilized erythrocytes, was employed to couple human IgG to sheep erythrocytes. The efficiency of conjugation, the recovery of cells, and the extent of labeling are noted. These conjugated erythrocytes were then tested for suitability in the hemolytic plaque assay, in a passive hemagglutination test, in a complement assay, and in the detection of rheumatoid factor. Although several methods were useful in a variety of situations, it was found that conjugation using a water soluble carbodiimide (1-ethyl-3-(3-dimethylaminopropyl) carbodiimide) at low temperature (4 degrees C) produced a uniformly acceptable product that was stable and reproducible over a seven week period. The use of this method for a diversity of antigens or haptens is discussed.

Animals↗
PubMed1976

Exocytosis in secretory cells of rat lacrimal gland. Peroxidase release from lobules and isolated cells upon cholinergic stimulation.

Release of peroxidase from secretory cells of rat lacrimal gland upon cholinergic stimulation was studied in vitro with single lobules and isolated cells (lacrimocytes). Isolated lobules, kept in Eagle's medium, remain structurally intact and reaction product of peroxidase is confined to cisternae of rough endoplasmic reticulum, elements of the Golgi apparatus, and all secretory granules. Morphologically, exocytosis occurs by membrane fusion and discharge of granule content. The highest rate of peroxidase released from lobules is observed at 10(-4) M carbamylcholine. The specific activity of peroxidase released into the medium is fourfold higher as compared to the lobules. Release of peroxidase is suppressed by atropine when added before or after the addition of carbamylcholine. At 4 degrees C, no peroxidase release occurs upon cholinergic stimulation. The exocytotic release of peroxidase is dependent on energy supply, as indicated by substantial inhibition (at 37 degrees C) under anoxic conditions or in the presence of dinitrophenol, KCN, or carboxyatractyloside. Furthermore, the process is sensitive to colchicine and vinblastine. Isolated lacrimocytes, consiting of 95% secretory acinar cells, are prepared by digestion with collagenase, hyaluronidase, and trypsin. They retain the characteristic polarity of secretory cells in situ, and localization of peroxidase is the same as in lobules. Since isolated lacrimocytes respond to cholinergic stimulation in the same way as lobules, the receptors are not damaged by the isolation procedure and appear to be associated directly with the exocrine cell. Oxygen uptake by isolated lacrimocytes is about 14 nmol O2 X min-1 X 10(-6) cells; it is about doubled by uncoupling with dinitrophenol. Oxygen uptake rises by 20-30% above the resting rate upon cholinergic stimulation. This additional uptake is suppressed by atropine or by added cholinesterase, indicating that continuous receptor occupancy may be required for the energy demand by exocytosis. On the basis of the specific activity of peroxidase in the medium, the energy demand resulting from cholinergic stimulation is estimated to be 0.08 mumol ATP (or energy-rich phosphate bonds) per microgram of protein released from the lacrimocytes.

Animals↗
PubMed1976

Serum-derived immunosuppressive substances. I. Partial purification and range of action.

Two alpha-globulin fractions which had in vivo and in vitro immunosuppressive activity were prepared from human serum. The larger fraction eluted from a molecular sieving gel in the albumin fraction and was heat labile whereas the smaller one was present in the elute fraction containing materials of 8,000-25,000 daltons and was heat stable. It is believed that the smaller of the two fractions is the immunoregulatory alpha-globulin described by several other investigators. The comparative activities of various starting materials and of partially purified derivatives in several systems (in vivo and in vitro) were examined. The possibility that these substances are lymphocytic chalones is considered.

Animals↗
PubMed1976

The bicarbonate ion pump in the endothelium which regulates the hydration of rabbit cornea.

1. Studies were made on the short-circuit current (s.c.c.) and fluid transport across rabbit corneal endothelium. 2. Normal s.c.c. of 27 muA.cm-2 is reduced to 19 muA.cm-2 in CO2-free Ringer, to 9 muA. cm-2 in HCO-3 -free Ringer and to zero in CO2 and HCO-3 -free Ringer. 3. Carbonic anhydrase inhibitors reduce s.c.c. from 27 to 19 muA.cm-2. Removal of exogenous CO2 causes no further reduction in s.c.c. 4. In CO2-free Ringer, net exogenous bicarbonate translocation is equal to s.c.c. 5. In all cases studied, net fluid transport across the endothelium in open circuit is directly proportional to s.c.c. 6. It is concluded that the endothelial 'pump' which regulates corneal hydration operates by 'pumping' bicarbonate ions into the aqueous humour. 7. Under physiological conditions, two thirds of the substrate is supplied by exogenous bicarbonate ions and one third is supplied by conversion of exogenous CO2 by intracellular carbonic anhydrase. 8. Metabolic CO2 does not participate significantly in the process, probably because it is at too low a concentration to compete effectively with exogenous CO2. 9. Electron histochemical studies suggest that carbonic anhydrase is located immediately underneath the posterior membrane of the endothelium, across which the active bicarbonate ion flux passes.

Animals↗
PubMed1975

A comparison of the unlabeled enzyme method with immunofluorescence for the evaluation of human immunologic renal disease.

The application of the unlabeled enzyme method to immunostaining of human renal biopsy material is described. The specificity and sensitivity of this technic were compared with those of standard immunofluorescent staining procedures. The unlabeled enzyme method, although a lengthier procedure, has proven to be as specific and at least as sensitive as conventional fluorescent staining. The advantages of the procedure are its permanence, its compatibility with conventional staining procedures, and the avoidance of fluorescent microscopy for evaluation.

Animals↗