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Biomedical subjects

W H Frey

Publications and source records attributed to W H Frey.

At least 73 records · Page 4Linked to original sources
PubMed1985

Glial fibrillary acidic protein and Alzheimer's disease.

A major protein associated with Alzheimer's disease (AD) was detected by an electrophoretic study of temporal cortex obtained at autopsy from patients affected with AD, non-AD dementia, and normal controls matched for age and sex. A markedly increased amount of a 50,000 dalton molecular weight protein, which has been identified as glial fibrillary acidic protein (GFAP), was observed in the crude nuclear fraction of temporal cortex from AD patients. These electrophoretic data may reflect the presence of GFAP immunopositive astrocytic processes that have been shown by immunocytologic methods to infiltrate the neurofibrillary tangles that characterize AD.

Alzheimer Disease↗
PubMed1984

Polyethylene glycol interferes with protein molecular weight determinations by gel filtration.

Gel filtration studies on Sephadex G-75 demonstrate markedly increased elution volumes for proteins chromatographed with polyethylene glycol. As little as 5% (w/v) polyethylene glycol in the applied protein sample can reduce apparent molecular weight estimates by gel filtration as much as 55%. Furthermore, gel filtration columns equilibrated with polyethylene glycol are not size-separating columns. Consequently, caution must be exercised when performing and interpreting gel filtration studies of proteins previously treated or precipitated with polyethylene glycol.

Chromatography, Gel↗
PubMed1983

A multiregional population-projection framework that incorporates both migration and residential mobility streams: application to metropolitan city-suburb redistribution.

"In this paper the author introduces a population-projection framework that incorporates interregional migration and intraregional residential mobility streams to project future population sizes both across and within regions in a manner that is consistent with existing migration theory. The author presents a general matrix model of the framework, shows how its parameters can be estimated from fixed-interval census migration data, and discusses how the framework can be employed to 'update' population projections when recent, more limited data sets become available. These features of the framework are demonstrated with intrametropolitan central-city-suburb projections for selected US Standard Metropolitan Statistical Areas over the period, 1970-2020."

Americas↗
PubMed1982

A comparison of peripheral and central human muscarinic cholinergic receptor affinities for psychotropic drugs.

A peripheral model offers a valuable research tool for the investigation of central cholinopathic disorders. The in vitro affinities of several psychotropic drugs for the muscarinic cholinergic binding sites of human caudate and erythrocyte were compared in competition with a tritiated antagonist (quinuclidinyl benzilate). The relative affinities of the drugs for both tissues were strikingly similar. Thus, the erythrocyte muscarinic receptor may represent an accessible in vitro assay for the characterization of central cholinopathic states.

Binding, Competitive↗
PubMed1982

Changing families and changing mobility: their impact on the central city.

Urban scholars and planners look to evidence of recent gains in the number of nontraditional households as a potential source of increase to the population sizes and tax bases of declining central cities. While it is now well established that substantial gains in the numbers of small, nontraditional households have occurred since the 1950s, it has not been demonstrated that: (a) these households are more likely to relocate in the city than traditional family households (husband-wife with children under 18); or (b) their cityward relocation patterns will significantly alter trends toward smaller city household populations. This paper addresses these questions by examining changes in city-suburb migration stream rates by household type over periods 1955-60, 1965-70 and 1970-75 for large metropolitan areas, and assesses their implications for potential changes in the aggregate sizes of city household populations.

Adolescent↗
PubMed1981

Stimulation of guanylate cyclase by EDTA and other chelating agents.

The partially purified soluble guanylate cyclase (GTP pyrophosphatelyase(cyclizing), EC 4.6.1.2) from human caudate nucleus is stimulated from 2 to 4-fold by metal chelating agents. EDTA (K 1/2 - 4.8 microM) is more potent than CDTA (K 1/2 = 13.2 microM) or EGTA (K 1/2 = 21.8 microM) at stimulating activity. Stimulation by chelating agents is apparently not due to removal of inhibitory divalent cations which contaminate the enzyme or reaction mixture. EDTA increases guanylate cyclase activity in part by increasing the affinity of the enzyme for the substrate (MgGTP) 10-fold. Dopamine inhibits partially purified guanylate cyclase in the presence or absence of EDTA. Dopamine increases the Ka of guanylate cyclase for the activator, free Mn2+, more than 50-fold, from 3 to 150 microM.

Caudate Nucleus↗
PubMed1981

Effect of stimulus on the chemical composition of human tears.

We examined the effect of the nature of the stimulus on the chemical composition of human tears. The protein concentration of emotional tears from women exceeded that of irritant-induced tears by 24% (P less than .01). Polyacrylamide disk gel electrophoresis disclosed no significant difference between the distribution of positively or negatively charged proteins of irritant-induced and emotional tears. Manganese concentrations in tears (30 ng/ml) exceeded serum concentrations from the same subjects by 30-fold. These manganese concentrations in tears were considerably less than previously reported values. We found no differences for the concentrations of protein or manganese in human tears between the sexes.

Adolescent↗
PubMed1981

Postmortem stability of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase in rat striatum.

The stability of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase was measured in homogenates of rat striatal tissue frozen from 0 to 24 h postmortem. ATPase, GTPase, and Mg2+-dependent guanylate cyclase activities showed no significant change over this period. Mn2+-dependent guanylate cyclase activity was stable for 10 h postmortem. Basal and dopamine-stimulated adenylate cyclase activity decreased markedly during the first 5 h. However, when measured in washed membrane preparations, these adenylate cyclase activities remained stable for at least 10 h. Therefore, the postmortem loss of a soluble activator, such as GTP, may decrease the adenylate cyclase activity in homogenates. These results are not consistent with an earlier suggestion that there is a postmortem degradation of the enzyme itself. Other kinetic parameters of dopamine-sensitive adenylate cyclase can also be measured independently of postmortem changes. Thus, it is possible to investigate kinetic parameters of dopamine-sensitive adenylate cyclase, guanylate cyclase, ATPase, and GTPase in human brain obtained postmortem.

Adenosine Triphosphatases↗
PubMed1980

Catecholamine-sensitive guanylate cyclase from human caudate nucleus.

Partial purification of soluble guanylate cyclase on DEAE-Sephacel yields two separate peaks of guanylate cyclase activity. After 10-fold purification of the soluble enzyme, guanylate cyclase is markedly inhibited by micromolar concentrations of dopamine (I50 = 0.2 microM). Dopamine inhibition is observed whether the reaction is conducted with Mn2+ or with Mg2+, under atmosphere or N2(g), and using enzyme from either peak from the DEAE-Sephacel column. Other catecholamines also inhibit partially purified guanylate cyclase with an order of potency at 1 microM of: dopamine = L-DOPA > norepinephrine = isoproterenol = adrenochrome > epinephrine. The structural requirements for inhibition are two free hydroxyl groups on the phenyl ring and an ethylamine side chain. Dopamine also inhibits the Triton X-100-solubilized microsomal guanylate cyclase after partial purification on DEAE-Sephacel. Neither chlorpromazine, propranolol, nor phentolamine at 20 microM effectively block the dopamine inhibition of partially purified soluble guanylate cyclase. Micromolar concentrations of the reducing agents dithiothreitol and glutathione also inhibit partially purified guanylate cyclase, but unlike these agents, catecholamines can inhibit whether added in the reduced or the oxidized forms. Inhibition of enzyme activity by micromolar concentrations of dopamine, adrenochrome, or dithiothreitol is rapidly reversed by dilution and the dopamine inhibition is competitive with MgGTP. Inhibition does not appear to involve covalent binding or to result from the ability of catecholamines to reduce the concentrations of oxygen or free radicals in solution.

Adrenochrome↗
PubMed1979

The changing impact of white migration on the population compositions of origin and destination metropolitan areas.

Increased migration to the sunbelt and the metropolitan-nonmetropolitan "turnaround" represent departures from long-standing redistribution trends. Although these patterns have been examined from a number of perspectives, their consequences for individual metropolitan areas have not yet been brought to light. In the present study, stream-disaggregated data for the late 1950s and late 1960s are employed to assess the impact of recent migration on the sizes and compositions of white populations in thirty-one large metropolitan areas. Most large northern SMSAs have been experiencing the "new" migration patterns since the late 1950s. They have incurred net out-movements of whites to both metropolitan and nonmetropolitan areas. In their exchanges with nonmetropolitan areas, however, they have managed to retain greater numbers of college graduates and professional workers. Southern and western SMSAs did not sustain losses to nonmetropolitan areas during either period. They did appear to gain both total and high status population as a result of interregional metropolitan redistribution.

Educational Status↗
PubMed1978

Population movement and city-suburb redistribution: an analytic framework.

This paper introduces an analytic framework that can be used to assess the relationships between individual movement differentials and place characteristics, on the one hand, and aggregate mobility levels and city-suburb population change (in size or composition), on the other. Application of this framework using census data for individual metropolitan areas allows the analyst to decompose population changes due to net migration into contributing mobility streams and their component rates which are subject to unique community and individual influences. The paper provides both theoretical and empirical rationale for the framework, illustrates its use with 1970 census data, and discusses its implications for empirical research on city-suburb population redistribution.

Humans↗
PubMed1977

Binding of acetyl-CoA to chicken liver pyruvate carboxylase.

Pyruvate carboxylase from chicken liver is a tetramer whose catalytic activity is completely dependent on the presence of acetyl-CoA. However, no direct evidence concerning the nature of the binding of the activator to the enzyme has been available. This is due in part to the instability of the enzyme and its ability to hydrolyze acetyl-CoA at an appreciable rate. The present studies on binding of the activator with the rapid flow dialysis method of Colowick and Womack ((1969) J. Biol. Chem. 244, 774-777) as modified by Klapper ((1970) Biochem. Biophys. Res. Commun. 38, 172-179) show four binding sites for acetyl-CoA. The binding dissociation constant at pH 7.2 is 13.9 muM as compared with an activation constant of 13.3 muM for the catalytic reaction at this pH. The relationship between acetyl-CoA concentration and catalytic activity is highly cooperative (nH = 2.9). The binding process also exhibits positive cooperativity but to a lower degree (nH = 1.9). Pyruvate carboxylase from chicken liver is rapidly inactivated and dissociated in the cold (0 degrees). The inactive protomeric form of the enzyme has been shown to be unable to bind acetyl-CoA at 0 degrees although the tetrameric species can do so. These results provide a plausible explanation for the catalytic inactivity of the protomer. The presence of acetyl-CoA results in an ultraviolet difference spectrum for the enzyme with a maximum at 280 nm. Half-maximal optical density difference is observed at an acetyl-CoA concentration of 9 muM, in reasonable agreement with the binding and activation constants.

Acetyl Coenzyme A↗