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G Weinbaum

Publications and source records attributed to G Weinbaum.

11 recordsLinked to original sources
PubMed1992

Specificity and sensitivity of the assay for elastin-derived peptides in chronic obstructive pulmonary disease.

One prediction of the protease-antiprotease hypothesis of chronic obstructive pulmonary disease (COPD) pathogenesis is the appearance of elastin-derived degradation products in the plasmas of affected patients that are due to the breakdown of alveolar interstitial elastin by an excess of elastolytic activity in the lung. We previously demonstrated a significant elevation of plasma elastin-derived peptides (EDP) in subjects with COPD in comparison with asymptomatic smokers with normal spirometry or normal nonsmokers. To better determine the selectivity of the assay for EDP as a marker of COPD, we measured plasma EDP levels in different patient populations. These included subjects with COPD, subjects with diseases that may involve accelerated elastolysis (pneumonia, atherosclerotic vascular disease, and inflammatory arthritis), subjects with diseases hypothesized to involve pulmonary inflammation without elastolysis (asthma and acute tracheobronchitis), asymptomatic smokers with normal spirometry, and healthy, nonsmoking subjects. Mean plasma EDP levels in subjects with COPD were elevated above those in all other subjects (p less than 0.01). The prospective analyses of specificity and sensitivity of plasma EDP levels as markers of COPD gave values of 91 and 65%, respectively. Utilizing receiver operating characteristic curve analysis to assess the diagnostic and screening performance of plasma EDP as a test for COPD (perfect test equals an area under the curve of 1.0), the area under the curve was 0.87, which compares favorably with many widely used clinical tests. These data demonstrate that the assay for plasma EDP is a quantitative, easily measured, and highly specific marker for subjects with COPD.

Adult↗
PubMed1979

Immunologic localization of elastin by electron microscopy.

Research on the pathogenesis of experimental emphysema has involved studies of the distribution of and destruction of elastin in the alveolar interstitium. The ill-defined organization of elastin in the alveolar interstitium makes it difficult to identify the elastin specifically by staining procedures ordinarily used for electron microscopy. This problem becomes more significant when the elastic tissue is fragmented during emphysema development and localization of the elastin fragments is essential. Therefore, a specific technique using high-titer antibodies against purified canine lung elastin was developed. The primary antibody was used on preembedded or etched postembedded sections. Localization of the antielastin IgG was accomplished with ferritin-labeled rabbit antisheep IgG as the secondary antibody. Treatment with the preimmune serum gave negligible ferritin background staining. The antielastin antibody did not react with lung connective tissue proteins such as the microfibrillar component of elastin or collagen or proteoglycan. The antielastin antibody appeared to be species specific. The method may be useful for studies of experimental emphysema.

Animals↗
PubMed1978

Purification and characterization of canine alpha-1-antiproteinase.

The principal canine plasma protease inhibitor, alpha-1-antiproteinase, has been purified 90-fold with a 25% yield to apparent homogeneity. The purification scheme includes anion-exchange chromatography, to separate away the bulk of the serum albumin; affinity chromatography by insolubilized concanavalin A, to remove most of the other serum proteins as well as traces of albumin; and, finally, sizing on Sephacryl-S-200. Unique to this purification scheme is the batch use of insolubilized hemoglobin--Sepharose beads to remove the ubiquitous contaminant haptoglobin. The purified material has an apparent molecular weight of 58 000, 11.2% carbohydrate, and an E280nm1% = 5.82, and can be separated by isoelectric focusing into at least two distinct forms with pI values of 4.40 and 4.52. In addition, canine alpha-1-antiproteinase is immunologically distinct from human alpha-1-antiproteinase.

Amino Acids↗
PubMed1977

Experimental emphysema induced with purified human neutrophil elastase: tissue localization of the instilled protease.

Human neutrophilic polymorphonuclear leukocyte (PMN) elastase was purified by affinity chromatography to greater than 95% homogeneity as judged by disc-gel electrophoresis. Dog lung elastin was prepared from alveolar-enriched tissue by prior extraction of soluble and collagenous lung proteins with 0.1 M NaOH at 98 degrees C. Digestion of the remaining insoluble residue by the purified PMN enzyme was monitored by Lowry assay of acid-soluble peptides released. The PMN enzyme possessed 60% of the digestive activity of crystallized porcine pancreatic elastase (weight:weight comparison) when tested in vitro against this substrate in phosphate-NaCl buffer at pH 7.5. Whole tissue studies were then performed in lungs of laboratory animals. One-ml samples containing purified PMN elastase were instilled into lavaged and saline-perfused isolated dog lung at the level of the sixth to seventh generation bronchus. Treatment with 384 mug of the PMN enzyme produced anatomic emphysema after a 90-min incubation at room temperature, which was comparable to that produced by 100 mug of porcine pancreatic elastase. Frozen sections of treated and control lungs were examined for the presence of PMN elastase by the indirect immunoperoxidase method using a monospecific rabbit antiserum against PMN elastase as the primary stain. Light microscopy revealed elastase bound to connective tissue in the treated lungs, in close proximity to aldehyde-fuchsin-counterstained elastic fibers. A similar experiment was tn of enzyme solutions containing 1;0 mg of elastase per ml produced discrete lesions within 90 min, as before. Light microscopic studies in conjunction with the indirect immunoperoxidase staining method again demonstrated elastase in association with connective tissue elements in the lesion area. In addition, part of the instilled protease could be demonstrated within alveolar macrophages. Electron microscopy combined with immunoperoxidase staining revealed direct attachment of th einstilled enzyme to elastic fibers within alveolar septa. In enzyme-treated tissue, some septa showed severe depletion of intercellular structures with the exception of colalgen, which was generally preserved. These results show that human leukocyte elastase penetrated dog alveolar septal connective tissue after airway instillation and that the enzyme attaches to elastic fibers, inducing histologic changes comparable to thos seen in human emphysema.

Animals↗
PubMed1975

Glucosamine-labelled envelope proteins of Escherichia coli K-12. I. Electrophoretic studies and partial fractionation of phenol-soluble proteins.

Hydrophobic envelope proteins were extracted by phenol from a glucosamine- and leucine-requiring mutant of Escherichia coli K-12 (E-110). Three protein fractions labelled with D-[1-14C]glucosamine and L-[4,5-3H]leucine were obtained by electrophoretic separation. Envelopes were isolated from cells labelled with D-[1-14C]glucosamine--HCL and acid hydrolyzed. At least 68% of the radioactivity was recovered as glucosamine and glucose with no random distribution of label. Fingerprinting of pronase digests of glucosamine-labelled proteins showed four radioactive spots associated with peptides. The glycoproteins were pronase- and trypsin-sensitive and had apparent molecular weights of 11 000 (fast mobility), 35 000 (intermediate mobility) and 62 000 (slow mobility) as estimated by sodium dodecyl sulfate-polyacrylamide disc electrophoresis. The two heavier fractions were labelled with meso-diamino[1,7-14C2]pimelic acid, while orth[32P]phosphate was not incorporated into any fraction. The glucosamine radioactivity of the fast fraction underwent rapid changes upon a chase with non-radioactive glucosamine. Using a Sephadex LH-20 column, the radioactive proteins were separated from the phenol and subsequently fractionated on a DEAE-cellulose column. The DEAE-cellulose fractions were distinct from each other in the number and composition of protein bands, when analyzed by sodium dodecyl sulfate-polyacrylamide disc electrophoresis. Radioactive bands with intermediate and fast electrophoretic mobilities were found in separate DEAE-cellulose fractions.

Bacterial Proteins↗
PubMed1975

Glucosamine-labelled envelope proteins of Escherichia coli K-12. II. Location in inner and outer membranes.

Outer and inner membranes were prepared from a culture of a glucosamine- and leucine-requiring mutant of Escherichia coli K-12, which was grown on L-[4,5-(3)H2]leucine and D-[1-(14)C]glucosamine and "chased" with unlabelled medium. Phenol-soluble glycoproteins were obtained from these membranes after phospholipid extraction. Sodium dodecyl sulfate-disc electrophoresis of the outer-membrane glycoproteins separated two components which were labelled with both isotopes and had a fast (F) and intermediate (I) migration. Dodecyl sulfate electrophoresis of the inner-membrane glycoproteins showed that only the F band incorporated both 14C and 3H labels. The 3H to 14C ratio in the F band from the outer membrane was completely different from the isotopic ratio in the F band from the inner membrane, indicating that these components were not identical despite their similar molecular weights. The F bands from both membranes lost their label during the chase with unlabelled medium, while the I band remained relatively stable. Chloroform-soluble 14C label extracted from the outer membrane decreased during the chase. In contrast, the chloroform-soluble 14C from the inner membrane, accumulated during the chase.

Bacterial Proteins↗
PubMed1975

A possible model for cell-cell recognition via surface macromolecules.

Alternative possibilities for the establishment of the proper cell distribution during embryogenesis are summarized at the beginning, followed by an assessment of the examples known so far where cell-cell recognition is known to be mediated via cell surface components. In the second part the species-specific recognition process which occurs during the sorting-out of dissociated sponge cells is analysed since it may serve as a possible model for cell-cell recognition in higher animals. Three possible mechanisms for the establishment of proper cell distribution are considered. These include, first, chemotaxis: secondly, guidance of cell or cell sheet movement by extracellular matrix or by surrounding cells and thirdly, random movement followed by recognition at the final point of destination. Recognition is necessary for both of the two latter processes, i.e. for cell guidance as well as for locking the cells into their final position after random movement. Two basically different recognition mechanisms should be distinguished from each other. On the one hand cells may recognize each other with the help of macromolecules situated in or just outside of the plasmamembrane which fit to each other like enzymes and substrates or antibodies and antigens. On the other hand, cells may exchange information by exchanging cytoplasmatic components via vesicles or gap junctions. The species-specific aggregation of dissociated sponge cells is considered to be a possible model for cell-cell recognition in higher animals. A proteoglycan-like intercellular macromolecule called aggregation factor seems to mediate recognition of a given species of cells in the reaggregation process of dissociated cells. The data available at the present time suggest that a monovalent surface macromolecule (baseplate) may mediate the recognition process probably by recognizing the carbohydrate side chains of the multivalent proteoglycan aggregation factor. A cell-free system was devised to mimic this aggregation process. Addition of aggregation factor to baseplate-coated sepharose beads of approximately the size of the original sponge cells has essentially the same characteristics as the cellular system. Macromolecule-coded surface information for the recognition between cells has not been established during the embryogenesis of higher animals and remains an interesting challenge.

Animals↗