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S L Wagner

Publications and source records attributed to S L Wagner.

At least 19 recordsLinked to original sources
PubMed1992

Potential role of protease nexin-2/amyloid beta-protein precursor as a cerebral anticoagulant.

The amyloid beta-protein precursor (APP) is the parent molecule to the amyloid beta-protein which is a major constituent of neuritic plaques and cerebrovascular deposits in Alzheimer's disease (AD). The protease inhibitor, protease nexin-2 (PN-2), is the secreted form of APP that contains the Kunitz protease inhibitor (KPI) domain. We reported that the predominant isoform of APP in human brain contains the KPI domain and is thus PN-2. Quantitation of PN-2/APP in various tissues revealed that it is primarily found in brain. Circulating blood platelets are another rich source of PN-2/APP. Platelet PN-2/APP is contained in platelet alpha granules and is secreted upon activation of platelets by physiological agonists. Protease inhibition measurements demonstrated that PN-2/APP is a potent inhibitor of intrinsic blood coagulation factor XIa. These findings suggest that PN-2/APP may play a role in the regulation of blood coagulation and platelets may serve as a systemic vehicle to deliver large amounts of this protein to sites of vascular injury. In addition, we propose that the rich, and relatively exclusive, investment of PN-2/APP in brain suggests that it may function locally as an intracerebral anticoagulant.

Amyloid beta-Protein Precursor↗
PubMed1992

Low cerebrospinal-fluid concentrations of soluble amyloid beta-protein precursor in hereditary Alzheimer's disease.

In Alzheimer's disease, deposits of amyloid beta-protein are apparently derived from intracellular processing of a large precursor protein. We have measured concentrations of this precursor in cerebrospinal fluid (CSF) from six members of a family affected by presenile Alzheimer's disease associated with a point mutation of the precursor gene. One gene carrier with clinical signs of the disorder had low CSF concentrations of the precursor, similar to those of three patients with sporadic Alzheimer's disease subsequently confirmed at necropsy. Two symptom-free gene carriers had CSF precursor concentrations similar to those of non-demented controls, though the value was lower in one, who had deficits revealed on neuropsychological testing, than in the other. These findings suggest that low concentrations of soluble amyloid precursor proteins in the CSF reflect the process that results in amyloid plaque formation and vascular deposition in Alzheimer's disease.

Adult↗
PubMed1992

High level expression, purification, and characterization of the Kunitz-type protease inhibitor domain of protease nexin-2/amyloid beta-protein precursor.

The protease inhibitor, protease nexin-2 (PN-2), is the secreted isoform of the Alzheimer's amyloid beta-protein precursor (A beta PP) that contains the Kunitz-type protease inhibitor (KPI) domain. Here we describe the use of the methylotrophic industrial yeast Pichia pastoris as a host system for the large scale production of the KPI domain of PN-2/A beta PP. In addition to the 57 amino acid KPI domain, the expression product contained an additional four amino acid residues at its amino terminus that correspond to amino acids 285-288 of A beta PP (Ponte et al. 1988 Nature 311:525-527). This expression system generated yields of greater than 1.0 gram of KPI domain per liter of fermentation media. The secreted 61 amino acid product was purified to homogeneity and biochemically characterized. Amino acid analysis and sequencing of the entire expressed KPI domain verified its integrity. Similar to native PN-2/A beta PP, the purified KPI domain potently inhibited trypsin, chymotrypsin, and coagulation factor XIa. Although heparin augments the inhibition of factor XIa by native PN-2/A beta PP it had no effect on the inhibition of factor XIa by expressed KPI domain suggesting that heparin binds to regions on native PN-2/A beta PP outside of the protease inhibitory domain. This KPI domain expression product should be useful in studying the physiologic and pathophysiologic functions of PN-2/A beta PP.

Amino Acid Sequence↗
PubMed1992

Dioxin intoxication from chronic exposure of horses to pentachlorophenol-contaminated wood shavings.

Investigations into the cause of health problems on a horse-breeding farm led to the discovery of high concentrations (630 to 9,810 mg/kg of bedding) of pentachlorophenol in wood shavings used as bedding for horses over a period of 2 to 4 years. Toxicologic signs in the horses were characteristic of toxic effects associated with exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans. Tissue residue analysis confirmed presence of toxic polychlorinated dibenzo-p-dioxin and dibenzofuran isomers known to be in pentachlorophenol, substantiating the bioavailability of polychlorinated dibenzo-p-dioxins and dibenzofurans in the wood shavings. The findings provide evidence that residue concentrations in the range of 2 ng/g of toxic polychlorinated dibenzo-p-dioxin isomers in liver or fat correlate with toxicologic effects in horses.

Animals↗
PubMed1992

Decreased levels of soluble amyloid beta-protein precursor in cerebrospinal fluid of live Alzheimer disease patients.

The amyloid beta-protein is deposited in senile plaques and the cerebrovasculature in Alzheimer disease (AD). Since it is derived from proteolytic processing of its parent protein, the amyloid beta-protein precursor (APP), we investigated whether levels of the secreted forms of APP are altered in cerebrospinal fluid (CSF) of AD patients. Quantitative immunoblotting studies with the anti-APP monoclonal antibody P2-1 revealed that probable AD patients had markedly lower CSF APP levels than did demented non-Alzheimer-type patients and healthy control subjects. Using antibody P2-1 in an enzyme-linked immunosorbent assay, we measured CSF levels of APP in a larger population consisting of 13 patients diagnosed with probable AD, 18 patients diagnosed with dementia (non-Alzheimer type), and 16 nondemented, healthy controls. Mean CSF levels of APP were approximately 3.5-fold lower in the live patients diagnosed with probable AD compared to the demented non-Alzheimer-type controls or the nondemented, healthy individuals. These findings suggest that abnormal metabolism of APP is reflected in the extracellular fluids of the central nervous system and that CSF levels of soluble APP provide a useful biochemical marker to assist in the clinical diagnosis of AD.

Alzheimer Disease↗
PubMed1992

Alzheimer's disease and hereditary cerebral hemorrhage with amyloidosis-Dutch type share a decrease in cerebrospinal fluid levels of amyloid beta-protein precursor.

The amyloid beta-protein is a 39-42 amino acid peptide that is deposited in senile plaques and in cerebral vessel walls in individuals with Alzheimer's disease, Down's syndrome, hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D), and, to a much lesser extent, normal aging. It is derived from abnormal proteolytic processing of its parent protein, the amyloid beta-protein precursor. Here we show that individuals with the HCHWA-D mutation and clinically manifesting the disease have markedly decreased cerebrospinal fluid levels of soluble amyloid beta-protein precursor (0.7 +/- 0.4 micrograms/ml) compared with age-matched normal subjects (3.0 +/- 0.2 micrograms/ml) as determined by quantitative immunoblotting and enzyme-linked immunosorbent assays. Similarly, age-matched patients diagnosed with probable Alzheimer's disease also have decreased cerebrospinal fluid levels of soluble amyloid beta-protein precursor (1.0 +/- 0.3 micrograms/ml). These parallel findings suggest a common biochemical marker for these two diseases and further establish the pathogenic relatedness of HCHWA-D and Alzheimer's disease.

Alzheimer Disease↗
PubMed1992

Aggregation of the amyloid precursor protein within degenerating neurons and dystrophic neurites in Alzheimer's disease.

Using a monoclonal antibody raised against purified, native, human protease nexin-2/amyloid precursor protein, which recognizes an amino terminal epitope on the amyloid precursor protein and detects all major isoforms of amyloid precursor protein, we examined the localization of the amyloid precursor protein within Alzheimer's and aged control brains. Very light cytoplasmic neuronal amyloid precursor protein staining but no neuritic staining was visible in control brains. In the Alzheimer's brain, we detected numerous amyloid precursor protein-immunopositive neurons with moderate to strong staining in select regions. Many neurons also contained varying levels of discrete granular, intracellular accumulations of amyloid precursor protein, and a few pyramidal neurons in particular appeared completely filled with amyloid precursor protein granules. "Ghost"-like deposits of amyloid precursor protein granules arranged in pyramidal, plaque-like shapes were identified. We detected long, amyloid precursor protein-immunopositive neurites surrounding and entering plaques. Many contained swollen varicosities along their length or ended in bulbous tips. Amyloid precursor protein immunoreactivity in the Alzheimer's brain was primarily present as granular deposits (plaques). The amyloid precursor protein granules do not appear to co-localize within either astrocytes or microglia, as evidenced by double-labeling immunohistochemistry with anti-glial fibrillary acidic protein and anti-leukocyte common antigen antibodies or Rinucus cummunicus agglutin lectin. Amyloid precursor protein could occasionally be detected in blood vessels in Alzheimer's brains. The predominantly neuronal and neuritic localization of amyloid precursor protein immunoreactivity indicates a neuronal source for much of the amyloid precursor protein observed in Alzheimer's disease pathology, and suggests a time-course of plaque development beginning with neuronal amyloid precursor protein accumulation, then deposition into the extracellular space, subsequent processing by astrocytes or microglia, and resulting in beta-amyloid peptide accumulation in plaques.

Aged↗
PubMed1991

The predominant form of the amyloid beta-protein precursor in human brain is protease nexin 2.

The amyloid beta protein and the amyloid beta-protein precursor (APP) are major constituents of senile plaques and cerebrovascular deposits in patients with Alzheimer disease and Down syndrome. Most human tissues contain mRNA that encodes forms of APP that contain the Kunitz protease inhibitor (KPI+) domain. A major 120-kDa protein corresponding to this KPI+ mRNA is also found in these tissues. This protein is identical to the protease inhibitor protease nexin 2. Brain contains an additional mRNA species that encodes a form of APP that lacks the KPI domain (KPI-). This latter mRNA has been suggested to encode a 105-kDa KPI- form of APP protein also found in brain. Using protease inhibitory functional assays, we show that both the 105-kDa and 120-kDa APP proteins in normal and Alzheimer disease brain contain the KPI domain. Moreover, KPI domain-specific precipitation assays reveal that KPI- forms of APP protein represent less than 14% of total brain APP. Lastly, an enriched fraction from total brain homogenate contains proteolytic activity that can process the purified 120-kDa KPI+ form of APP into a 105-kDa form, resulting in a high-molecular-mass doublet identical to that seen in brain. These findings indicate that although KPI- APP mRNA is abundant in brain, little corresponding protein is present. Thus, KPI+ APP protein (equivalent to protease nexin 2) is the predominant form of APP in human brain.

Alzheimer Disease↗
PubMed1991

Residues of pentachlorophenol and other chlorinated contaminants in human tissues: analysis by electron capture gas chromatography and electron capture negative ion mass spectrometry.

Samples of human tissues including testes, kidneys, prostate glands, livers, and adipose tissues removed at autopsy were analyzed for pentachlorophenol (PCP) and nonachloro-2-phenoxyphenol (NCPP); the fat samples were also analyzed for other chlorinated contaminants. Electron capture gas chromatography was used to quantitate the residues after isolation and cleanup. Identity of the residues was confirmed by electron capture negative ion mass spectrometry. All tissues analyzed for PCP tested positive with a range from 0.007 ppm (microgram/g) in subcutaneous fat to 4.14 ppm in testis. Residues of NCPP were much lower, ranging from levels below the detection limit to 0.59 ppm in testis. The highest average residues, based on the lipid content of the tissue, of PCP (1.09 ppm) and of NCPP (0.19 ppm) were found in testis followed by kidney (0.95 ppm PCP), prostate (0.84 ppm PCP), and liver (0.59 ppm PCP). Residues of these chemicals in the adipose tissues were on the average about 40 times lower than the residues in the non-fatty tissues. Other chlorinated contaminants found in the subcutaneous fat included hexa-, hepta-, and octa-chlorodibenzo-p-dioxins at sub-ppb levels and DDE averaging 2.47 ppm.

Adipose Tissue↗
PubMed1991

Inhibitors of urokinase and thrombin in cultured neural cells.

Recent studies have suggested important roles for certain proteases and protease inhibitors in the growth and development of the CNS. In the present studies, inhibitors of urokinase or thrombin in cultured neural cells and serum-free medium from the cells were identified by screening for components that formed sodium dodecyl sulfate-stable complexes with 125I-urokinase or 125I-thrombin. Rinsed glioblastoma possessed two components that complexed 125I-urokinase. One was type 1 plasminogen activator inhibitor (PAI-1), because the 125I-urokinase-containing complexes were immunoprecipitated with anti-PAI-1 antibodies. The other component formed complexes with 125I-urokinase that were not recognized by antibodies to PAI-1 or protease nexin-1 (PN-1). Its identity is unknown. In addition to these cell-bound components, the glioblastoma cells also secreted two inhibitors that formed complexes with 125I-urokinase; one was PAI-1, and the other was PN-1. The secreted PN-1 also formed complexes with 125I-thrombin. It was the only thrombin inhibitor detected in these studies. Human neuroblastoma cells did not contain components that formed detectable complexes with either 125I-urokinase or 125I-thrombin. However, human neuroblastoma cells did contain very low levels of PN-1 mRNA and PN-1 protein. Added PN-1 bound to the surface of both glioblastoma and neuroblastoma cells. This interaction accelerated the inhibition of thrombin by PN-1 and blocked the ability of PN-1 to form complexes with 125I-urokinase. Thus, cell-bound PN-1 was a specific thrombin inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloid beta-Protein Precursor↗
PubMed1990

Immunopurification and protease inhibitory properties of protease nexin-2/amyloid beta-protein precursor.

Protease nexin-2 (PN-2) is a protease inhibitor that is synthesized and secreted by a variety of extravascular cells including human fibroblasts. It forms sodium dodecyl sulfate-stable complexes with trypsin, the epidermal growth factor binding protein and the gamma-subunit of nerve growth factor. Recently we reported that PN-2 is the secreted form of the amyloid beta-protein precursor (APP) and is a potent inhibitor of chymotrypsin. Here we describe a two-step procedure to purify PN-2/APP using a monoclonal antibody immunoaffinity column. We also quantitated the protease inhibitory properties of purified PN-2/APP on a number of serine proteases. PN-2/APP was a potent inhibitor of coagulation factor XIa with a Ki = 2.9 x 10(-10). The inhibition of factor XIa by PN-2/APP was augmented by heparin and resulted in a Ki = 5.5 x 10(-11) M. Trypsin and chymotrypsin were also effectively inhibited with a Ki = 4.2 x 10(-10) and 1.6 x 10(-9), respectively. PN-2/APP also inhibited the epidermal growth factor binding protein, the gamma-subunit of nerve growth factor, and chymase and plasmin to a lesser extent. In view of recent findings that PN-2/APP is contained in alpha-granules of platelets and is secreted upon platelet activation, the potent inhibition of factor XIa suggests that PN-2/APP may play a regulatory role in the coagulation pathway at vascular wound sites. In addition, these studies define biochemical activities of PN-2/APP which may be involved in regulating proteases that lead to the generation and deposition of the beta-protein in neurodegenerative lesions associated with Alzheimer's disease and Down's syndrome.

Amino Acid Sequence↗
PubMed1990

Pesticide illness surveillance: review of the National Pesticide Hazard Assessment Program.

Regarding consultations on pesticide exposures by Oregon State University, the following information is summarized: 1) source of queries; 2) locations of exposure; 3) types of chemicals; and 4) nature of the illnesses. The majority of queries involve nonagricultural exposures in the home and workplace. Principal sources of referral are from the National Pesticide Telecommunications Network (toll-free number), state departments of agriculture, and state extension services. In addition to illnesses, the system also responds to press releases such as those that occurred after the withdrawal of chlordane. Previously unsuspected clinical problems have been reported (suggesting new areas of research need), including cases associated with long-acting organophosphates, such as chlorpyrifos, and with the pyrethroids.

Adult↗
PubMed1990

Protease nexin-1. Localization in the human brain suggests a protective role against extravasated serine proteases.

Protease nexin-1 (PN-1) is a potent thrombin inhibitor that is identical to the glia-derived neurite-promoting factor or glia-derived nexin. Here we report immunocytochemical studies of adult human cerebral cortex that revealed the presence of strong immunoreactivity for PN-1 in capillaries and in the smooth muscle cells of arteries and arterioles. Expression of PN-1 was also abundant in astroglial processes in the parenchyma and in perivascular astroglial endfeet of human cerebral cortex. In situ hybridization with an 35S-labeled RNA antisense probe for PN-1 resulted in significant labeling of astrocytes and blood vessels. Because thrombin is known to cause retraction of neurites and modification of astrocytic morphology at low concentrations, PN-1 around blood vessels may play a major protective role against extravasation of thrombin and possibly other serine protease into the human brain.

Alzheimer Disease↗
PubMed1990

[Hypomagnesemic coma in heart failure: description of a case].

The case of a patient developing hypomagnesemic encephalopathy and coma secondary to intensive treatment for severe cardiac failure, is reported. Following an early improvement of symptoms and signs of cardiac failure, a rapidly developing neurologic disorder appeared. This was characterized by insomnia, agitation, mental derangement and, finally, sopor and I-II degree coma. Serum magnesium concentration was 1.0 mEq/l. Magnesium sulfate iv infusion was followed by a immediate and complete recovery from the neurological disorder. Patients with cardiac failure undergoing prolonged intensive therapy are prone to develop hypomagnesemia. This electrolyte alteration may be responsible for symptoms and signs of central nervous system involvement (metabolic encephalopathy) that need to be differentiated from those of organic origin.

Coma↗
PubMed1989

Protease nexin-II, a potent antichymotrypsin, shows identity to amyloid beta-protein precursor.

Protease nexin-II (PN-II) is a protease inhibitor that forms SDS-resistant inhibitory complexes with the epidermal growth factor (EGF)-binding protein, the gamma-subunit of nerve growth factor, and trypsin. The properties of PN-II indicate that it has a role in the regulation of certain proteases in the extracellular environment. Here we describe more of the amino-acid sequence of PN-II and its identity to the deduced sequence of the amyloid beta-protein precursor (APP). Amyloid beta-protein is present in neuritic plaques and cerebrovascular deposits in individuals with Alzheimer's disease and Down's syndrome. A monoclonal antibody against PN-II (designated mAbP2-1) recognized PN-II in immunoblots of serum-free culture medium from human glioblastoma cells and neuroblastoma cells, as well as in homogenates of normal and Alzheimer's disease brains. In addition, mAbP2-1 stained neuritic plaques in Alzheimer's disease brain. PN-II was a potent inhibitor of chymotrypsin with an inhibition constant Ki of 6 x 10(-10)M. Together, these data demonstrate that PN-II and APP are probably the same protein. The regulation of extracellular proteolysis by PN-II and the deposition of at least parts of the molecule in senile plaques is consistent with previous reports that implicate altered proteolysis in the pathogenesis of Alzheimer's disease.

Alzheimer Disease↗