The demonstration of both type I and type II components in the difference spectra produced by aniline and N-ethylaniline with cytochrome P-450

1. The metabolism in vitro and microsomal interactions of (+)-amphetamine, (−)-amphetamine, (+)-benzphetamine and (−)-benzphetamine were studied with hepatic microsomes from phenobarbitone-pretreated male rabbits. 2. (+)-Benzphetamine was N-demethylated 30–35% faster than (−)-benzphetamine, but the apparent Michaelis constants for the two enantiomers were similar. 3. (−)-Amphetamine was deaminated about 200% faster than (+)-amphetamine. 4. The benzphetamine enantiomers gave qualitatively and quantitatively identical type I microsomal difference spectra (peak, 390nm; trough, 425nm) indicating identical apparent binding affinities for microsomes and identical spectral changes at maxima (ΔEmax. values). 5. The amphetamine enantiomers gave qualitatively identical type II microsomal difference spectra (peak, 433nm; trough, 395nm). However, the type II spectral data indicated that (+)-amphetamine had a markedly higher apparent binding affinity than (−)-amphetamine for microsomes. The amphetamine enantiomers gave identical ΔEmax. values. 6. The benzphetamine enantiomers (0.5mm) enhanced the rate of microsomal cytochrome P-450 reduction by NADPH by 400–500%, (+)-benzphetamine enhancing the rate 20–25% more than (−)-benzphetamine. 7. The amphetamine enantiomers decreased the rate of microsomal cytochrome P-450 reduction by NADPH. At a concentration of 2mm, (+)-amphetamine decreased the rate more than (−)-amphetamine. 7. All four enantiomers enhanced microsomal NADPH oxidation.

Download Full-text

Responses of Medullary Dorsal Horn Neurons to Corneal Stimulation by CO2 Pulses in the Rat

Journal of Neurophysiology ◽

10.1152/jn.1999.82.5.2092 ◽

1999 ◽

Vol 82 (5) ◽

pp. 2092-2107 ◽

Cited By ~ 44

Author(s):

Harumitsu Hirata ◽

James W. Hu ◽

David A. Bereiter

Keyword(s):

Thalamic Nucleus ◽

Receptive Fields ◽

Male Rats ◽

Cervical Cord ◽

Type I ◽

Type Ii ◽

Upper Cervical ◽

The Difference ◽

Evoked Activity ◽

Stimulation Of

Corneal-responsive neurons were recorded extracellularly in two regions of the spinal trigeminal nucleus, subnucleus interpolaris/caudalis (Vi/Vc) and subnucleus caudalis/upper cervical cord (Vc/C1) transition regions, from methohexital-anesthetized male rats. Thirty-nine Vi/Vc and 26 Vc/C1 neurons that responded to mechanical and electrical stimulation of the cornea were examined for convergent cutaneous receptive fields, responses to natural stimulation of the corneal surface by CO2 pulses (0, 30, 60, 80, and 95%), effects of morphine, and projections to the contralateral thalamus. Forty-six percent of mechanically sensitive Vi/Vc neurons and 58% of Vc/C1 neurons were excited by CO2 stimulation. The evoked activity of most cells occurred at 60% CO2 after a delay of 7–22 s. At the Vi/Vc transition three response patterns were seen. Type I cells ( n = 11) displayed an increase in activity with increasing CO2 concentration. Type II cells ( n = 7) displayed a biphasic response, an initial inhibition followed by excitation in which the magnitude of the excitatory phase was dependent on CO2 concentration. A third category of Vi/Vc cells (type III, n = 3) responded to CO2 pulses only after morphine administration (>1.0 mg/kg). At the Vc/C1 transition, all CO2-responsive cells ( n = 15) displayed an increase in firing rates with greater CO2 concentration, similar to the pattern of type I Vi/Vc cells. Comparisons of the effects of CO2 pulses on Vi/Vc type I units, Vi/Vc type II units, and Vc/C1 corneal units revealed no significant differences in threshold intensity, stimulus encoding, or latency to sustained firing. Morphine (0.5–3.5 mg/kg iv) enhanced the CO2-evoked activity of 50% of Vi/Vc neurons tested, whereas all Vc/C1 cells were inhibited in a dose-dependent, naloxone-reversible manner. Stimulation of the contralateral posterior thalamic nucleus antidromically activated 37% of Vc/C1 corneal units; however, no effective sites were found within the ventral posteromedial thalamic nucleus or nucleus submedius. None of the Vi/Vc corneal units tested were antidromically activated from sites within these thalamic regions. Corneal-responsive neurons in the Vi/Vc and Vc/C1 regions likely serve different functions in ocular nociception, a conclusion reflected more by the difference in sensitivity to analgesic drugs and efferent projection targets than by the CO2 stimulus intensity encoding functions. Collectively, the properties of Vc/C1 corneal neurons were consistent with a role in the sensory-discriminative aspects of ocular pain due to chemical irritation. The unique and heterogeneous properties of Vi/Vc corneal neurons suggested involvement in more specialized ocular functions such as reflex control of tear formation or eye blinks or recruitment of antinociceptive control pathways.

Download Full-text

Number of fiber bundles in the fetal anterior talofibular ligament

10.21203/rs.3.rs-683859/v1 ◽

2021 ◽

Author(s):

Mutsuaki Edama ◽

Tomoya Takabayashi ◽

Hirotake Yokota ◽

Ryo Hirabayashi ◽

Chie Sekine ◽

...

Keyword(s):

Fiber Bundle ◽

Fiber Bundles ◽

Anterior Talofibular Ligament ◽

Type I ◽

Type Ii ◽

Crown Rump Length ◽

Type Iii ◽

The Difference ◽

And Inversion

Abstract Background For the anterior talofibular ligament (ATFL), a three-fiber bundle has recently been suggested to be weaker than a single or double fiber bundle in terms of ankle plantarflexion and inversion braking function. However, the studies leading to those results all used elderly specimens. Whether the difference in fiber bundles is a congenital or an acquired morphology is important when considering methods to prevent ATFL damage. The purpose of this study was to classify the number of fiber bundles in the ATFL of fetuses. Methods This study was conducted using 30 legs from 15 Japanese fetuses (mean weight, 1764.6 ± 616.9 g; mean crown-rump length, 283.5 ± 38.7 mm; 8 males, 7 females). The ATFL was then classified by the number of fiber bundles: Type I, one fiber bundle; Type II, two fiber bundles; and Type III, three fiber bundles. Results Ligament type was Type I in 5 legs (16.7%), Type II in 21 legs (70%), and Type III in 4 legs (13.3%). Conclusions The present results suggest that the three fiber bundles of the structure of the ATFL may be an innate structure.

Download Full-text

The catalytic activity of the endoplasmic reticulum-resident protein microsomal epoxide hydrolase towards carcinogens is retained on inversion of its membrane topology

Biochemical Journal ◽

10.1042/bj3190131 ◽

1996 ◽

Vol 319 (1) ◽

pp. 131-136 ◽

Cited By ~ 6

Author(s):

Thomas FRIEDBERG ◽

Romy HOLLER ◽

Bettina LÖLLMANN ◽

Michael ARAND ◽

Franz OESCH

Keyword(s):

Endoplasmic Reticulum ◽

Catalytic Activity ◽

Epoxide Hydrolase ◽

Membrane Topology ◽

Microsomal Epoxide Hydrolase ◽

Type I ◽

Type Ii ◽

Membrane Orientation ◽

N Terminus ◽

Cytochrome P 450

Diol epoxides formed by the sequential action of cytochrome P-450 and the microsomal epoxide hydrolase (mEH) in the endoplasmic reticulum (ER) represent an important class of ultimate carcinogenic metabolites of polycyclic aromatic hydrocarbons. The role of the membrane orientation of cytochrome P-450 and mEH relative to each other in this catalytic cascade is not known. Cytochrome P-450 is known to have a type I topology. According to the algorithm of Hartman, Rapoport and Lodish [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 5786–5790], which allows the prediction of the membrane topology of proteins, mEH should adopt a type II membrane topology. Experimentally, mEH membrane topology has been disputed. Here we demonstrate that, in contrast with the theoretical prediction, the rat mEH has exclusively a type I membrane topology. Moreover we show that this topology can be inverted without affecting the catalytic activity of mEH. Our conclusions are supported by the observation that two mEH constructs (mEHg1 and mEHg2), containing engineered potential glycosylation sites at two separate locations after the C-terminal site of the membrane anchor, were not glycosylated in fibroblasts. However, changing the net charge at the N-terminus of these engineered mEH proteins by +3 resulted in proteins (++mEHg1 and ++mEHg2) that became glycosylated and consequently had a type II topology. The sensitivity of these glycosylated proteins to endoglycosidase H indicated that, like the native mEH, they are still retained in the ER. The engineered mEH proteins were integrated into membranes as they were resistant to alkaline extraction. Interestingly, an insect mEH with a charge distribution in its N-terminus similar to ++mEHg1 has recently been isolated. This enzyme might well display a type II topology instead of the type I topology of the rat mEH. Importantly, mEHg1, having the natural cytosolic orientation, as well as ++mEHg1, having an artificial luminal orientation, displayed rather similar substrate turnovers for the mutagenic metabolite benzo[a]pyrene 4,5-oxide. To our knowledge this is the first report demonstrating that topological inversion of a protein within the membrane of the ER has only a moderate effect on its enzymic activity, despite differences in folding pathways and redox environments on each side of the membrane. This observation represents an important step in the evaluation of the influence of mEH membrane orientation in the cascade of events leading to the formation of ultimate carcinogenic metabolites, and for studying the general importance of metabolic channelling on the surface of membranes.

Download Full-text

Blood clinicopathological differences between type I and II ketosis in dairy cows

Indian Journal of Animal Research ◽

10.18805/ijar.7495 ◽

2015 ◽

Author(s):

XU Chuang ◽

Shen Tai-yu ◽

YAO Yuan ◽

Yu Hong-jiang ◽

XIA Cheng ◽

...

Keyword(s):

Dairy Cows ◽

Dairy Cow ◽

Plasma Concentrations ◽

Elisa Test ◽

Type I ◽

Type Ii ◽

Hydroxybutyric Acid ◽

Cattle Farm ◽

The Difference ◽

Heilongjiang Of China

The purpose was to determine the difference of blood clinicopathological changes between type I and type II ketosis in dairy cow. Fifty-eight cows, from dairy cattle farm in Heilongjiang of China, were included. An ELISA test was used to evaluate the blood indicators. The plasma concentrations of beta-hydroxybutyric acid (BHBA) and insulin sensitivity decreased, and the plasma concentration of glucose (Glc), non-esterified fatty acid (NEFA) and bilirubin content increased in type II ketosis group compared with the type I ketosis group. These results showed that there was a difference in etiology between type II ketosis and type I ketosis. Type II ketosis was not only associated with energy metabolism and insulin resistance, but also with oxidative stress and liver function. It laid the foundation for further investigate the mechanism and prevention of type II ketosis in the future.

Download Full-text

Mechanism of inhibition by carbonyl cyanide m-chlorophenylhydrazone and sodium deoxycholate of cytochrome P-450-catalysed hepatic microsomal drug metabolism

Biochemical Journal ◽

10.1042/bj1600075 ◽

1976 ◽

Vol 160 (1) ◽

pp. 75-83 ◽

Cited By ~ 6

Author(s):

I B Tsyrlov ◽

O A Gromova ◽

V V Lyakhovich

Keyword(s):

Sodium Deoxycholate ◽

Protonated Form ◽

Microsomal Membrane ◽

Limiting Factor ◽

Type I ◽

Difference Spectra ◽

Nadph Cytochrome ◽

Carbonyl Cyanide ◽

Rate Limiting ◽

Cytochrome P 450

1. Treatment of liver microsomal fraction with 0.03-0.12% sodium deoxycholate and 0.005-0.06 mM carbonyl cyanide m-chlorophenylhydrazone decreases phospholipid-dependent hydrophobicity of the microsomal membrane, assayed by the kinetics of 8-anilinonaphthalene-1-sulphonate binding and ethyl isocyanide difference spectra. 2. Sodium deoxycholate at a concentration of 0.01% lacks its detergent properties, but competitively inhibits aminopyrine binding and activates the initial rate of NADPH-cytochrome P-450 reductase. In the presence of 0.03-0.09% sodium deoxycholate the rate-limiting factor in p-hydroxylation of aniline is the content of cytochrome P-450. and that for N-demethylation of aminopyrine is the activity of NADPH-cytochrome P-450 reductase. 3. Carbonyl cyanide m-chlorophenylhydrazone has no effect on the binding and metabolism of aniline; investigation of its inhibiting effect on aminopyrine N-demethylase established that the rate-limiting reaction is the dissociation of the enzyme-substrate complex in the microsomal preparations. 4. In the mechanism of action of carbonyl cyanide m-chlorophenylhydrazone the key step may be the electrostatic interaction of its protonated form and one of the forms of activated oxygen at the catalytic centre of cytochrome P-450. 5. at least two different phospholipid-dependent hydrophobic zones are assumed to exist in the microsomal membrane, both coupled with cytochrome P-450. One of them reveals selective sensitivity to the protonation action of carbonyl cyanide m-chlorophenylhydrazone and contains the ‘binding protein’ for type I substrates and NADPH-cytochrome P-450 reductase; the other contains the cytochrome P-450 haem group and binding sites for type II substrates.

Download Full-text

Analytic non-Abelian gravitating solitons in the Einstein–Yang–Mills–Higgs theory and transitions between them

The European Physical Journal C ◽

10.1140/epjc/s10052-021-09197-3 ◽

2021 ◽

Vol 81 (5) ◽

Author(s):

Fabrizio Canfora ◽

Seung Hun Oh

Keyword(s):

Energy Levels ◽

Higgs Field ◽

Scalar Fields ◽

Family Type ◽

Type I ◽

Type Ii ◽

Yang Mills ◽

Completely Regular ◽

The Difference ◽

Abelian Fields

AbstractTwo analytic examples of globally regular non-Abelian gravitating solitons in the Einstein–Yang–Mills–Higgs theory in (3 + 1)-dimensions are presented. In both cases, the space-time geometries are of the Nariai type and the Yang–Mills field is completely regular and of meron type (namely, proportional to a pure gauge). However, while in the first family (type I) $$X_{0} = 1/2$$ X 0 = 1 / 2 (as in all the known examples of merons available so far) and the Higgs field is trivial, in the second family (type II) $$X_{0} = 1/2$$ X 0 = 1 / 2 is not 1/2 and the Higgs field is non-trivial. We compare the entropies of type I and type II families determining when type II solitons are favored over type I solitons: the VEV of the Higgs field plays a crucial role in determining the phases of the system. The Klein–Gordon equation for test scalar fields coupled to the non-Abelian fields of the gravitating solitons can be written as the sum of a two-dimensional D’Alembert operator plus a Hamiltonian which has been proposed in the literature to describe the four-dimensional Quantum Hall Effect (QHE): the difference between type I and type II solutions manifests itself in a difference between the degeneracies of the corresponding energy levels.

Download Full-text

Genetic basis of the formation and identity of type I and type II neurons in Drosophila embryos

Development ◽

10.1242/dev.124.14.2819 ◽

1997 ◽

Vol 124 (14) ◽

pp. 2819-2828 ◽

Cited By ~ 2

Author(s):

M. Vervoort ◽

D.J. Merritt ◽

A. Ghysen ◽

C. Dambly-Chaudiere

Keyword(s):

Cell Communication ◽

Sense Organ ◽

Type I ◽

Type Ii ◽

Neuronal Fate ◽

Late Step ◽

Alternative Type ◽

The Difference ◽

Dependent Lineages ◽

Multidendritic Neurons

The embryonic peripheral nervous system of Drosophila contains two main types of sensory neurons: type I neurons, which innervate external sense organs and chordotonal organs, and type II multidendritic neurons. Here, we analyse the origin of the difference between type I and type II in the case of the neurons that depend on the proneural genes of the achaete-scute complex (ASC). We show that, in Notch- embryos, the type I neurons are missing while type II neurons are produced in excess, indicating that the type I/type II choice relies on Notch-mediated cell communication. In contrast, both type I and type II neurons are absent in numb- embryos and after ubiquitous expression of tramtrack, indicating that the activity of numb and the absence of tramtrack are required to produce both external sense organ and multidendritic neural fates. The analysis of string- embryos reveals that when the precursors are unable to divide they differentiate mostly into type II neurons, indicating that the type II is the default neuronal fate. We also report a new mutant phenotype where the ASC-dependent neurons are converted into type II neurons, providing evidence for the existence of one or more genes required for maintaining the alternative (type I) fate. Our results suggest that the same mechanism of type I/type II specification may operate at a late step of the ASC-dependent lineages, when multidendritic neurons arise as siblings of the external sense organ neurons and, at an early step, when other multidendritic neurons precursors arise as siblings of external sense organ precursors.

Download Full-text