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Biomedical subjects

G C Stone

Publications and source records attributed to G C Stone.

At least 19 recordsLinked to original sources
PubMed1992

Analysis of individual CNS protein synthesis.

A procedure for labeling rat CNS proteins in vivo which is useful for behavioral and pharmacological studies has been developed. Intraventricular administration of 35S-methionine through bilateral indwelling cannulae provided reproducible and highly specific radiolabeling of proteins from frontal cortex (FC), parietal cortex (PC), occipital cortex (OC), striatum (ST), septal nuclei (SN), amygdala (AM), hippocampus (HIP), thalamus (TH), brain stem (BS) and cerebellum (CB). Relative rates of synthesis of over 200 individual proteins were subsequently analyzed by 2DGE. Regional analysis demonstrated increased labeling of a protein of MW 28 kD and pI 6.4 in the hippocampus that was barely detectable in striatum of control rats. In heat-shocked animals, there was increased relative synthesis of the 74 kD Heat Shock Protein in both the septal nuclei and hippocampus.

Amygdala↗
PubMed1989

The Fc binding site for streptococcal protein G is in the C gamma 2-C gamma 3 interface region of IgG and is related to the sites that bind staphylococcal protein A and human rheumatoid factors.

The isolated 35 kDa fragment of protein G obtained by papain digestion of group G streptococci was found to bind solid phase intact IgG, Fc (2C gamma 2 + 2C gamma 3 domains), F(ab')2 and F(acb)2 (F(ab')2 + 2C gamma 2 domains) fragments but not pFc' (2C gamma 3 domains) fragments. The level of binding to rabbit F(acb)2 and rabbit F(ab')2 fragments was similar. Protein G binding to solid phase Fc fragments was inhibited by IgG, Fc, staphylococcal protein A and its monovalent fragment D, but was enhanced by F(ab')2 fragments. Chemical modification of tyrosine but not histidine residues of IgG abrogated its ability to inhibit the binding of protein G to solid phase Fc fragments. Protein G was found to strongly inhibit the binding of a monoclonal and a polyclonal human rheumatoid factor to IgG. These findings indicate that protein G binds with separate sites to the Fc and F(ab')2 fragments of IgG, that the interaction with the Fc fragment occurs at the C gamma 2-C gamma 3 domain interface region and that tyrosine but not histidine residues in this area are likely involved. The relationship of the Fc fragment-binding site specificity of protein G to that of other microbial IgG binding proteins and human rheumatoid factors is discussed.

Animals↗
PubMed1989

A vasculopathy with deposition of lambda light chain crystals.

An 82-year-old man and a 34-year-old woman developed subacute, obstructive, fatal vasculopathies characterized by extensive crystalline tissue deposits and monoclonal lambda light chain serum components. Cryocrystalglobulinemia was also present in one patient, and the purified crystals contained only lambda light chain dimers. Although the presentation of these patients resembled that of systemic necrotizing vasculitis, histologic evidence of inflammation was lacking and their subsequent rapid clinical deterioration was not altered by corticosteroid therapy, and in one case cyclophosphamide and plasmapheresis. Both patients died within 3 weeks of presentation.

Adult↗
PubMed1989

Heat stress increases delivery of a unique sub-population of proteins conveyed by fast axonal transport.

The effect of heat stress on protein synthesis and fast axonal transport was examined in vitro in bullfrog dorsal root ganglion (DRG) and associated spinal/sciatic nerve. Qualitative and quantitative changes of individual 35S-methionine-labelled proteins were determined following DRG labelling and fast transport in respective nerves via two-dimensional gel electrophoresis/autoradiography. Elevation of temperature from 18 degrees C to 33 degrees C for up to 6 hr resulted in a marked increase in synthesis of five individual DRG species of approximately 74,000 daltons that comigrate with heat shock proteins (HSPs). A quantitative comparison of species within this subset revealed two subgroups differentially affected by stress. The three most basic proteins were induced to approximately 1300% of unstressed controls after 6 hr of stress, while the two most acidic species demonstrated an increase to only 300% of controls over the same period. The relative abundance of 25 additional DRG proteins were uneffected by heat stress. Of 70 35S-labelled fast-transported proteins similarly analyzed, 15, comprising 5 families, were consistently transported at greater than 150% of controls following up to 6 hr of heat stress. Over this period all 15 proteins shared a similar profile of abundance relative to non-induced proteins. Transport was elevated to the greatest extent after 2 hr of stress, declined after 3 hr, and tended to rebound at later times. The remaining 55 fast-transported protein spots analyzed were unaffected. An increased delivery of this unique sub-population of 15 fast-transported proteins suggests a possible involvement in early cellular events that mediate heat stress in the nervous system.

Animals↗
PubMed1989

Metalloendoprotease inhibitors block fast axonal transport.

Metalloendoprotease activity that was sensitive to the metal chelator 1,10-phenanthroline and to synthetic dipeptide substrates of the enzyme was detected in homogenates of dorsal root ganglia (DRG) and spinal nerve from the bullfrog. Exposure of an intact in vitro preparation of DRG and spinal nerves to 1,10-phenanthroline led to a dose-dependent depression in the accumulation of fast-transported 3H-labeled protein proximal to a nerve ligature. In nonligated preparations, the chelator treatment reduced the amount of transported protein entering the nerve; no marked effect on the transport rate was observed. Exposure of a desheathed region of spinal nerve to 1,10-phenanthroline, while DRG were maintained in control medium, resulted in a slight depression of fast transport. This effect was not dose dependent over the range that produced a dose response when both DRG and spinal nerve were exposed to the drug. Treatment of DRG and spinal nerve with the metalloendoprotease substrate analogues carbobenzoxy (CBZ)-Ser-Leu-amide or CBZ-Gly-Leu-amide inhibited fast axonal transport, whereas treatment with CBZ-Gly-Gly-amide, which is not a substrate, had no detectable effect on transport. Selective exposure of desheathed nerve trunk to CBZ-Ser-Leu-amide inhibited fast transport, but the effect was less marked than when DRG and nerve trunk were treated. Although previous studies have focused on the role of metalloendoprotease activity in exocytosis, the present data suggest that the enzyme may also be involved in earlier stages of intracellular transport.

Animals↗
PubMed1988

Absence of auto-antiidiotypic activity between the IgM and IgG fractions of human mixed cryoglobulins.

Experimental animal models and observations in humans suggest that levels of Id and auto-anti-Id fluctuate reciprocally after Ag stimulation. In human monoclonal B cell disorders, however, the co-existence of paraprotein Id and its auto-anti-Id has been described in essential mixed cryoglobulinemia and in association with acquired C1 inhibitor deficiency. Because the majority of cryoglobulin IgM possess rheumatoid factor activity and thus bind the Fc region of IgG, we examined potential idiotypic interactions between cryoglobulin IgM and F(ab')2 fragments of autologous cryoglobulin IgG fractions. A rabbit antibody to the pepsin agglutinator site of human F(ab')2 was used as detection reagent. By recognizing epitopes exposed on F(ab')2 after the removal of Fc determinants by pepsin digestion, this reagent eliminates the detection of contaminating intact IgG. In a sensitive assay, we were unable to detect idiotypic interactions between the separated IgM and pepsin-digested IgG fractions of 10 mixed cryoglobulins. On the basis of these results, we suggest that in mixed cryoglobulinemia, the coexistence of paraprotein Id and its auto-anti-Id is unlikely.

Antibodies, Anti-Idiotypic↗
PubMed1988

Heat stress induces changes in protein synthesis and fast axonal transport in bullfrog sensory neurons.

The effects of heat stress on protein synthesis and fast axonal transport were examined in an in vitro bullfrog primary afferent neuron preparation. The magnitude of effect was determined for individual [35S]methionine-labelled protein species separated via two-dimensional gel electrophoresis. Elevation of temperature of the preparation from 18 degrees C to 33 degrees C caused a transient inhibition of synthesis of non-heat-shock proteins, whereas the synthesis of a 74,000-dalton protein increased to 927% of controls after 4 h. Similar prolonged stress conditions had no effect on the relative abundance of 36 individual, newly synthesized proteins undergoing fast axonal transport. A dramatic exception was represented by a 55,000-dalton glycoprotein whose fast transport was increased to 291% of control. The increase in transport of this protein during a time when synthesis and transport of other non-heat-shock proteins were not enhanced suggests that it may play a unique role in the early cellular events that mediate survival or thermotolerance in the neuron.

Animals↗
PubMed1988

Fc epitopes for human rheumatoid factors and the relationships of rheumatoid factors to the Fc binding proteins of microorganisms.

Work from our laboratories has shown that the major antigenic determinants for rheumatoid factors (RFs) are in the C gamma 2-C gamma 3 interface region of IgG in the same area that binds staphylococcal protein A (SPA). Furthermore, the Fc binding proteins of groups A, C and G streptococci as well as the Fc binding proteins induced on cell surfaces by herpes simplex virus type I also bind to the same area of IgG. These binding site similarities between RFs and the microbial Fc binding proteins suggested conformational similarities between the RF antigen combining regions and the Fc binding regions of the microbial proteins. This hypothesis was supported by the observation that antibodies to SPA bind to the antigen combining regions of most RFs as well as to the Fc binding region of the T15 group A streptococcal Fc binding protein. These findings indicate that RFs bear the conformational internal image of these microbial proteins and suggest that RFs could arise as antibodies to the idiotypic determinants on antibodies to microbial Fc binding proteins. Alternatively, microbial Fc binding proteins could present IgG to the immune system in a way that renders specific areas of the C gamma 2-C gamma 3 interface region immunogenic. These relationships between RFs and microbial Fc binding proteins may prove to be important for our understanding of the generation of RFs in rheumatoid arthritis.

Binding Sites↗
PubMed1987

Human rheumatoid factors bear the internal image of the Fc binding region of staphylococcal protein A.

The binding specificity of rheumatoid factors (RFs) to human Fc resembles that of some microbial Fc-binding proteins, suggesting conformational similarities in their Fc-binding regions. Using polyclonal chicken antibodies against SPA, we have detected a crossreactive determinant shared by human RFs from different individuals, but not by non-RF IgM and IgG. Chicken anti-SPA was shown to bind to 18 of 19 IgM RFs and 2 of 2 IgG RFs isolated from different individuals. This binding was inhibitable with SPA, fragment D of SPA, human IgG, and Fc fragment of IgG. The binding site for RF was located on the Fab' fragment of chicken anti-SPA. The antigenic mimicry of RFs by a protein of microbial origin suggests that the immune response to infectious agents could induce or modulate RF production through an internal image autoantiidiotype mechanism.

Animals↗
PubMed1987

Complex compartmentation of tyrosine sulfate-containing proteins undergoing fast axonal transport.

The compartmentation of fast-transported proteins that possess sulfated tyrosine residues--sulfoproteins--has been examined for further resolution of the possible significance of sulfated tyrosine in routing and delivery of fast-transported proteins. In vitro fast axonal transport of [35S]methionine- or 35SO4-labeled proteins was measured in dorsal root ganglion neurons for analysis of protein compartmentation en route and in synaptic regions. When membrane fractions were exposed to Na2CO3 for separation of "lumenal" and peripheral membrane proteins from integral components of the membrane, approximately 20% of the [35S]methionine incorporated into fast-transported proteins was present in a carbonate-releasable form in the axon, whereas 53% of the incorporated 35SO4 was released by carbonate. Eighty percent of the 35SO4 in this releasable fraction was acid labile, typical of sulfate ester-linked to tyrosine. Sulfoproteins were also detected in synaptosomes and were released into the extracellular medium in a calcium-dependent fashion, an observation suggesting that fast-transported sulfoproteins are secreted. Of the remaining 47% of the fast-transported 35SO4-labeled proteins resistant to carbonate treatment (the integral membrane protein fraction), nearly 60% of the 35SO4 was acid labile. Other membrane stripping agents, such as 0.1 M NaOH, 0.5 M NaCl, or mild trypsin treatment, failed to remove acid-labile 35SO4-labeled species from carbonate-treated membrane. Quantitative comparisons of several of the most abundant sulfoproteins resolved via two-dimensional gel electrophoresis confirmed that approximately 7% of each of the species remained associated with carbonate-treated membranes, presumably as integral membrane components.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Malignant schwannoma of the ovary. Report of a case.

A malignant schwannoma, apparently arising in the left ovary of a 71-year-old woman is described. The patient had no stigmata of von Recklinghausen's disease. The tumor was located in the position of the left ovary and had metastasized throughout the peritoneal cavity. The neural sheath origin of the tumor was confirmed by electron microscopic examination. The tumor is thought to have arisen from small nerves in the ovarian hilus.

Aged↗
PubMed1986

A double-isotope procedure for examining protein microheterogeneity: multiple forms of fast-transported glycoproteins and sulfoproteins possess a common polypeptide chain.

Several fast-transported proteins that appear as single bands after sodium dodecyl sulfate-polyacrylamide gel electrophoresis resolve into multiple spots during isoelectric focusing. A method was devised for determining if such microheterogeneity in net charge indicates that individual polypeptides have been posttranslationally modified to differing extents. Dorsal root ganglia were pulse-labeled with [35S]methionine and either [3H]leucine or [3H]proline, proteins fast-transported into peripheral sensory axons were separated by two-dimensional gel electrophoresis, and isotope incorporation ratios of proteins associated with individual gel spots were determined. When four microheterogeneous glycoproteins were analyzed, each protein "family" showed markedly similar isotope ratios for its three to seven characteristic spots. Such ratios differed between families by almost twofold. In addition, a group of nonglycosylated, sulfate-containing proteins was identified as a family on the basis of the similar isotope incorporation ratios of its component spots. These results suggest that protein microheterogeneity can result from variable sulfation of tyrosine residues as well as from variation in sialic acid-containing oligosaccharide side-chains. More generally, the method can be utilized to test for protein microheterogeneity in cases where the amounts of protein are too low to permit peptide mapping analysis and where the nature of the charge-altering modification is unknown.

Animals↗
PubMed1986

Past and current trends in patient noncompliance research: focus on diseases, regimens-programs, and provider-disciplines.

Patient noncompliance is discussed from an historical perspective with special attention given to the fact that although the medical profession was aware of noncompliance from the earliest times the first research on noncompliance was not done until the 1940's. Trends within the literature on patient noncompliance published between 1943 and 1984 are examined. The largest share of contributions being made to the noncompliance literature was and is from journals devoted to general medicine and psychiatry. The largest share of research is with patients suffering from hypertension, psychiatric patients, and children. An increasing amount of attention is being paid to diabetic patients. The bulk of the research on compliance remains patient-focused, with relatively little but much needed research designed to study characteristics of providers, regimens, or the health care setting. There are good reasons for compliance researchers to consider diabetology as a worthwhile area for investigations.

Classification↗
PubMed1985

Malignant lymphoma presenting as Kaposi's sarcoma in a homosexual man with the acquired immunodeficiency syndrome.

A homosexual man had Kaposi's sarcoma of the skin and lymph nodes. After a brief response to interferon, the patient developed new skin lesions. Massive bleeding in the gastrointestinal tract prompted endoscopy, which showed tumor involvement of the stomach, believed to be Kaposi's sarcoma. At autopsy, a diffuse lymphoma was found involving the skin and gastrointestinal tract, forming collision tumors in regions that contained Kaposi's sarcoma. Lymphomatous tissue, but not uninvolved lymph node or spleen, contained Epstein-Barr virus DNA, as shown by DNA hybridization studies. Epstein-Barr virus may play a role in the development of lymphoma in immunosuppressed patients. Unusual manifestations of tumors, such as the massive gastrointestinal bleeding seen in this case, may indicate the development of a second neoplasm.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Involvement of coated vesicles in the initiation of fast axonal transport.

The present study examines whether coated vesicles play a role in the intrasomal transit of newly synthesized fast-transported proteins. Coated vesicles isolated from bullfrog brain were shown to have a protein composition and ultrastructure similar to purified bovine brain coated vesicles. Bullfrog brain was then used as unlabeled carrier for the isolation of coated vesicles from dorsal root ganglia labeled with [3H]leucine. Fast-transported [35S]methionine-labeled proteins were generated in separate preparations from sciatic nerve, and co-electrophoresed on two-dimensional gels with [3H]proteins of the coated vesicle fraction. The [35S]Met fluorographic X-ray film pattern was used as a guide to remove gel regions which were tested for the presence of 3H. By this means, 45 of 67 individual fast-transported proteins examined were found to contain significant levels of 3H. The fact that these proteins have similar net charge and molecular weight characteristics to the mature fast-transported proteins with which they co-migrated, suggests that such species have already undergone post-translational modifications prior to becoming associated with coated vesicles. Since most modifications of this type occur in the Golgi apparatus, it appears that the majority of fast-transported proteins are isolated in association with a population of post-Golgi coated vesicles. The role of coated vesicles is incorporated into a model describing the pathway taken by fast-transported proteins during the initiation of fast axonal transport.

Animals↗
PubMed1984

Fast axonal transport of tyrosine sulfate-containing proteins: preferential routing of sulfoproteins toward nerve terminals.

The presence of a subset of fast-transported proteins containing sulfate while lacking carbohydrate residues [Stone et al. (1983). J. Neurochem. 41:1085-1089] was confirmed by two-dimensional gel electrophoretic analysis of individual fast-transported proteins double-labeled with 35SO4 and [3H]mannose. Analysis by high-pressure liquid chromatography revealed that the sulfate moieties of these "sulfoproteins" are linked to tyrosine residues. Separation of fast-transported 35SO4-labeled proteins delivered to local regions of axon from proteins en route toward terminal regions demonstrated, on the basis of acid lability of tyrosine-bound sulfate, that the sulfoproteins were localized preferentially in the wavefront of fast-transported proteins. Analysis of individual sulfoproteins confirmed differential transport in that sulfoproteins were present at threefold greater amount in the wavefront than in material off-loaded to local regions of the axon. By contrast, nonsulfated species of molecular weights similar to those of the sulfoproteins were detected in nearly equal amounts in both regions of the transport profile. Treatment of nerve segments containing total 35SO4-labeled fast-transported proteins with sodium carbonate led to solubilization of half the protein-bound sulfate. Exposure of the solubilized proteins to mild acid resulted in the release of approximately 80% of the 35SO4 associated with this fraction. Two-dimensional gel patterns displaying carbonate releasable or nonreleasable fractions are consistent with the most abundantly labeled sulfoproteins being transported within membrane-bound organelles. In terms of apparent destination and subcellular compartmentalization, the sulfoproteins meet critical requirements for consideration as secretable fast-transported proteins.

Animals↗
PubMed1984

Measuring adequacy of physician performance. A preliminary comparison of four methods in ambulatory care of chronic obstructive pulmonary disease.

Issues that arise in the development of methods for measuring adequacy of physician performance (MAPP) are discussed. The comparative content validity, scorability, cost, and acceptability of four MAPP strategies are assessed using a sample of clinic-based physicians treating 30 patients with chronic obstructive pulmonary disease (COPD). Criteria for adequate care are contained in a "criteria map." No one of the four methods (physician interview, patient interview, videotaped observation, and chart audit) was best at capturing all aspects of the management of COPD. The relative content validity of a method depended on the aspect of care evaluated. The interviews provided the broadest range of information and the chart audit the most limited. The patient interview yielded the largest proportion of encounters upon which physician performance could be scored, although specific criteria map subscales were differentially scorable depending on the method used. Relative cost and acceptability are also discussed.

Ambulatory Care↗