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C L Barnes

Publications and source records attributed to C L Barnes.

At least 73 records · Page 4Linked to original sources
PubMed1988

Structure of chlorobis(dicyclohexylphenylphosphine)gold(I).

[AuCl[C6H11)2(C6H5)P]2], Mr = 781.2, monoclinic, P2(1), a = 11.117 (4), b = 13.606 (5), c = 12.284 (4) A, beta = 109.59 (3) degrees, V = 1753 (2) A3, Z = 2, D chi = 1.48 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 43.8 cm-1, F(000) = 792, T = 296 K, final R = 0.024 for 3239 unique observed reflections. The formation of complexes of the type LnAuX, where L is a phosphine, and X is halide or pseudohalide, shows considerable dependence on the nature of the phosphine. When L = Ph3P, three- and four-coordinated complexes are very easily prepared. However, for L = Cy3P, only linearly coordinated complexes could be isolated. The geometry of the title complex, with L = CyPhP, is best described as distorted trigonal planar. The P-Au-P angle is 158.24 (5) degrees while the P-Au-Cl angles are 92.63 (6) and 108.71 (6) degrees. Au-P distances are 2.300 (1) and 2.324 (1) A while Au-Cl is 2.744 (2) A.

Gold↗
PubMed1988

Structure of cis-Pt(asb)2Cl2, a platinum(II) complex with a styrylbenzothiazole ligand.

cis-Bis[2-(2-acetoxystyryl)benzothiazole]dichloroplatinum(II), [PtCl2(C17H13NO2S)2], Mr = 856.7, triclinic, P1, a = 12.145 (6), b = 12.859 (4), c = 11.021 (5) A, alpha = 105.88 (3), beta = 90.64 (4), gamma = 87.64 (4) degrees, V = 1654 (2) A3, Z = 2, D chi = 1.72 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 46.1 cm-1, F(000) = 840, T = 296 K, final R = 0.029 for 6121 unique observed reflections. The [PtCl2(asb)2] complex has square-planar geometry about the Pt, with the asb coordinated to the Pt through the N of the thiazole ring. The average Pt-N and Pt-Cl bond distances are 2.035 (1) and 2.287 (5) A. The ligand is non-planar with an average dihedral angle of 36 (3) degrees between the benzothiazole and the benzene rings. The dihedral angles between the platinum coordination plane and the benzothiazole and benzene rings are 78 (4) and 69 (7) degrees respectively. The acetoxybenzene rings in the two ligands have different orientations with respect to the olefin C atoms.

Antineoplastic Agents↗
PubMed1988

Structure of ferrichrome-type siderophores with dissimilar N delta-acyl groups: asperchrome B1, B2, B3, D1, D2 and D3.

Asperchromes are a series of iron-chelating compounds which contain a cyclic hexapeptide backbone as in ferrichrome siderophores and differ from the latter in having heterogenous acyl groups in the ornithine side chains. The molecular structures of the asperchrome B and D series have been determined by 1H- and 13C-NMR spectroscopy; single-crystal X-ray diffraction was used to determine the detailed structural features of asperchrome B1 and asperchrome D1. Asperchrome B1 crystallizes in the triclinic space group P1 with a = 1.3143(5) nm, b = 1.2200(5) nm, c = 0.8949(3) nm, alpha = 105.17(4) degrees, beta = 94.03(3) degrees, gamma = 109.65(3) degrees, V = 1.2843 nm3, Z = 1, rho chi = 1.446 g cm-3. Final R = 0.054 for 4625 reflections measured at 138 K using MoK alpha. Asperchrome D1 crystallizes in the monoclinic space group P2(1) with a = 1.2248(11) nm, b = 1.3795(9) nm, c = 1.3644(6) nm, beta = 93.24(6) degrees, V = 2.3016 nm3, Z = 2, rho chi = 1.418 g cm-3. Final R = 0.110 for 3180 reflections measured at 138 K using MoK alpha radiation. The conformation of the molecular backbone and iron coordination geometry in both asperchrome B1 and D1 compare well with those observed in other known ferrichrome siderophores. The differences in the acyl groups are illustrated and the structural results are correlated with their iron transport properties.

Amino Acid Sequence↗
PubMed1988

Crystal and molecular structure of Destruxin B.

The cyclic hexadepsipeptide mycotoxin Destruxin B, produced by Metarrhizium anisopliae, crystallizes in the orthorhombic space group P212121, with a = 11.010(2)A, b = 14.679(5)A, c = 21.273(7)A and Z = 4. The structure was solved by direct methods and refined by least-squares technique to a final unweighted R value of 0.051, for 3361 reflections with I greater than 3 sigma (I). The backbone of the peptide is asymmetric and is made of 5 trans peptide and ester units and 1 cis peptide unit. The backbone conformation of this cyclic depsipeptide is very similar to that of Roseotoxin B, an analogous mycotoxin produced by Trichothecium roseum. The conformation in the crystalline state also correlates well with the solution conformation, as reported from proton n.m.r. studies. The crystal packing is directed by van der Waals contacts.

Amino Acid Sequence↗
PubMed1987

Circadian rhythms of serum gastrin and plasma cholecystokinin in rodents.

Fluctuations in serum gastrin and plasma cholecystokinin (CCK) over a 24-hr period were examined in fasted and freely fed adult BALB/c mice and Sprague Dawley rats. Eighty-four mice and 84 rats were caged in groups of (six) each and placed in separate isolation chambers with light from 0600 to 1800 hr (CST) daily (LD 12:12). After standardization for 30 days, one-half of the animals were fasted 24 hr prior to circadian sampling, and the remainder were allowed continuous access to food. Animals were removed and killed by rapid cervical dislocation every 4 hr beginning at 0800 hr for seven time points. Blood was collected and serum gastrin and plasma CCK were measured by specific radioimmunoassays. The data document a circadian bioperiodicity for serum gastrin and plasma CCK. The parameters of the rhythms, evaluated by cosinor rhythmometric methods, are characterized by an acrophase that occurs in the dark period for both fed and fasted rodents and a mesor that is higher in fed than fasted animals. Circadian sampling time and nutritional status appear to be important in studies involving serum levels of gastrin and plasma CCK in rodents.

Animals↗
PubMed1986

Anterograde transsynaptic transport of WGA-HRP in the limbic system of rat and monkey.

The lectin tracer, wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP), was injected into the entorhinal cortex in rat and monkey brains. Tracer labeling was followed in the entorhinal projection to dentate gyrus and hippocampus, i.e. along the perforant pathway. Besides labeling perforant pathway terminals in the outer two-thirds of stratum moleculare in the dentate gyrus, reaction product was also observed within stratum granulosum. We conclude that labeling of dentate granule cells was the result of anterograde transsynaptic transport of WGA-HRP. The evidence thus provides an example of anterograde transsynaptic transport: in the limbic system; and at an excitatory synapse.

Animals↗
PubMed1984

Alzheimer's disease: cell-specific pathology isolates the hippocampal formation.

Examination of temporal lobe structures from Alzheimer patients reveals a specific cellular pattern of pathology of the subiculum of the hippocampal formation and layers II and IV of the entorhinal cortex. The affected cells are precisely those that interconnect the hippocampal formation with the association cortices, basal forebrain, thalamus, and hypothalamus, structures crucial to memory. This focal pattern of pathology isolates the hippocampal formation from much of its input and output and probably contributes to the memory disorder in Alzheimer patients.

Aged↗
PubMed1984

Extracellular siderophores from Aspergillus ochraceous.

A large number of iron-chelating compounds (siderophores) were isolated from supernatants of iron-deficient cultures of a mold isolate, subsequently identified as Aspergillus ochraceous . Siderophores in their iron chelate form were purified to homogeneity by using Bio-Gel P2, silica gel, and C-18 bonded silica gel (reverse-phase) columns. Most of these compounds, as identified by 1H and 13C nuclear magnetic resonance spectroscopy and X-ray crystallography, belong to the ferrichrome family. The organism produces ferrirubin and ferrichrysin as the predominant and the second major compound (62 and 15% of the total siderophores), respectively. Ferrichrysin appears as the first siderophore in the medium on day 2 of growth. Several of the other siderophores are novel and ranged in quantities from 0.2 to 5% of the total. The trivial names asperchrome A, B1, B2, C, D1, D2, and D3 are proposed for these novel compounds, which are all members of the ferrichrome family, and all but the first one contain a common Orn1 - Orn2 - Orn3 - Ser1 -Ser2-Gly cyclic hexapeptide ring with three dissimilar ornithyl delta-N-acyl groups. Another compound which appeared late in the growth period was similar to fusarinine C ( fusigen ). All of these compounds showed growth factor activity to various extents in bioassays with Arthrobacter flavescens Jg-9. None of these compounds showed antibacterial activity against Escherichia coli or Bacillus megaterium.

Aspergillus↗
PubMed1983

Enhanced acetylcholinesterase staining in the hippocampal perforant pathway zone after combined lesions of the septum and entorhinal cortex.

A lesion of the septum or a transection of the fimbria-fornix diminishes most, but not all, acetylcholinesterase (AChE) staining in the hippocampal formation. The residual AChE is located in the outer part of the molecular layer of the hippocampal CA1 zone and adjacent subicular field (zone 31). We report that following combined lesions of the septum and entorhinal cortex, the residual hippocampal AChE staining pattern expands and occupies the zone innervated normally by perforant pathway terminals from the entorhinal cortex.

Acetylcholinesterase↗
PubMed1981

Structure of ferric pseudobactin, a siderophore from a plant growth promoting Pseudomonas.

Both plant growth promoting Pseudomonas B10 and its yellow-green, fluorescent iron transfer agent (siderophore) pseudobactin enhance the growth of the potato and control certain phytopathogenic microorganisms. The structure of the little compound has been determined by single-crystal X-ray diffraction methods using counter data. The structure consisted of a linear hexapeptide, L-Lys-D-threo-beta-OH-Asp-L-Ala-D-allo-Thr-L-Ala-D-N delta-OH-Orn, in which the N delta-OH nitrogen of the ornithine was cyclized with the C-terminal carboxyl group, and the N epsilon-amino group of the lysine was linked via an amide bond to a fluorescent quinoline derivative. The iron-chelating groups consisted of a hydroxamate group derived from N delta-hydroxyornithine, an alpha-hydroxy acid derived from beta-hydroxyaspartic acid, and an o-dihydroxy aromatic group derived from the quinoline moiety. The combination of metal-chelating ligands and the alternating L- and D-amino acids was unusual. The little compound crystallized as a single coordination isomer with the lambda absolute configuration. The present study is the first structural determination of a fluorescent siderophore. In the crystal structure, ferric pseudobactin formed a dimer, which constituted the asymmetric unit. The asymmetric unit also contained 26 water molecules. The molecules in the dimer were related by a pseudo-2-fold symmetry axis. Red-brown crystals of ferric pseudobactin (C42H57N12O16Fe . 13H2O), obtained from pyridine-acetic acid buffer solution equilibrated with water, conformed to space group I2 with a = 29.006 (23) A, b = 14.511 (13) A, c = 28.791 (21) A, and beta = 96.06 (5) degrees at -135 (2) degrees C. For eight molecules per unit cell, the calculated density was 1.38 g/cm3; the observed density was 1.40 g/cm3. The structure was refined by least-squares methods with anisotropic thermal parameters for all nonhydrogen atoms to a final R factor of 0.08 (8989 observed reflections).

Amino Acid Sequence↗
PubMed1979

The cells of origin of the commissural afferents to the area dentata in the mouse.

The hippocampal commissural projection to the area dentata of the mouse was studied using the retrograde horseradish peroxidase (HRP) technique. Small volumes of HRP injected into the molecular layer of the fascia dentata or various subareas of regio inferior of the hippocampus (fields CA3a-c) resulted inlabeled perikarya in the contralateral hippocampus and area dentata. The commissural projection to the fascia dentata was observed to originate exclusively from cells within the hilus fasciae dentatae (CA4) of the contralateral area dentata. There was evidence of a considerable spread of commissural innervation along the septotemporal axis preferentially in the septal direction, confirming earlier observations. In contrast to the septotemporal spread, a sharp homotopic spatial organization was found in the mediolateral direction. For example, injections into the lateral portion of field CA3 (CA3a) resulted in HRP-positive cell bodies only in the contralateral field CA3a. When injections were made which apparently labeled all of the commissural fibers, the HRP reaction product was found in neurons both in the entire regio inferior and as far as the innermost point of the hilus fasciae dentatae; the majority of labeled cells were located in hippocampal subfield CA3c. No labeled cells were observed beyond the tip of the mossy fibers in regio superior.

Afferent Pathways↗
PubMedDate not supplied

Two new trichothecenes from Fusarium sporotrichioides.

Two new trichothecenes, 8-n-pentanoylneosolaniol and 8-n-hexanoylneosolaniol, were isolated from corn grits cultured with Fusarium sporotrichioides. The structures of these compounds were elucidated using gc-ms, nmr, X-ray crystallography, and other spectroscopic techniques. Seven known trichothecenes were also isolated, and the relative cytotoxicity of these nine trichothecenes in cultured baby hamster kidney (BHK-21) cells was determined.

Animals↗
PubMedDate not supplied

Discoid lateral meniscus in a young child: case report and review of the literature.

Management of discoid lateral meniscus in a 6-month-old child is discussed. The patient presented with a lateral knee mass and an associated popping sound of the joint during flexion and extension. The diagnosis, which the authors believe to be the youngest presentation of this entity, was confirmed by arthrography. Computed tomographic features and magnetic resonance images of the discoid meniscus are presented. Management and theories of etiology of the discoid lateral meniscus are discussed.

Arthrography↗
PubMedDate not supplied

Pediatric pelvic ring fractures.

Pelvic fractures are uncommon in children, yet they rank second to those of the skull in terms of complications. Thirty-six pediatric patients who sustained pelvic fractures were retrospectively studied, and a recent follow-up examination was conducted in 29 of the patients. All fractures were classified using Torode and Zieg's system, and the severity of injury was classified using the Modified Injury Severity Score (MISS). Associated injuries occurred in 67% of the patients, with long-term morbidity or mortality in 30%. The high probability of associated injuries must be appreciated, as even minimal bony injury may be associated with life-threatening visceral injuries and morbidity.

Adolescent↗