Induction and axonal localization of epithelial/epidermal fatty acid-binding protein in retinal ganglion cells are associated with axon development and regeneration

Epithelial/epidermal fatty acid-binding protein (E-FABP) is induced in peripheral neurons during nerve regeneration and is found at high levels in central neurons during neuronal migration and development. Furthermore, E-FABP expression is required for normal neurite outgrowth in PC12 cells treated with nerve growth factor (NGF). The present study examined whether E-FABP plays a role in retinal ganglion cell (RGC) differentiation and axon growth. Rat retinal tissues from embryonic (E) and postnatal (P) development through adulthood were examined using immunocytochemical labeling with E-FABP and growth-associated protein 43 (GAP-43) antibodies. E-FABP colocalized with GAP-43 at E14 through P10. At E14, E-FABP immunoreactivity was confined to the somas of GAP-43-positive cells in the ganglion cell layer, but it was localized to their axons by E15. The axons in the optic nerve were GAP-43-positive and E-FABP-negative on E15, but the two proteins were colocalized by E18. Retinal cultures at E15 confirmed that E-FABP and GAP-43 colocalize in RGCs. Postnatally, labeling was present between P1 and P10 but decreased at older ages and was minimally present or absent in adult animals. Western immunoblotting revealed that at E18, P1, and P10 E-FABP levels were at least fourfold greater than those in the adult. By P15, protein levels were only twofold greater, with adult levels reached by P31. Furthermore, E-FABP could be reinduced during axon regeneration. Dissociated P15 retinal cells cultured in the presence of brain-derived neurotrophic factor, ciliary neurotrophic factor, and basic fibroblast growth factor exhibited sixfold more GAP-43 and E-FABP double-positive RGCs (cell body and axons) than controls. Moreover, all GAP-43-immunoreactive RGCs were also positive for E-FABP. Taken together, these results indicate the following: 1) E-FABP is expressed in RGCs as they reached the ganglion cell layer and 2) E-FABP plays a functional role in the elaboration of RGC axons in both development and regeneration.

Depletion of a fatty acid-binding protein impairs neurite outgrowth in PC12 cells

Epithelial fatty acid-binding protein (E-FABP) is up-regulated in rat dorsal root ganglia after sciatic nerve crush and in differentiating neurons during development. The present study investigates the role of E-FABP during nerve growth factor (NGF)-mediated neurite outgrowth in PC12 cells. Undifferentiated PC12 cells express low levels of E-FABP, while NGF triggers a 6- and 8-fold induction of E-FABP mRNA and protein, respectively. Up-regulation of E-FABP mRNA occurs as early as 24 h after NGF treatment and remains highly expressed over the course of several days, corresponding to NGF-mediated neurite outgrowth. Withdrawal of NGF leads to down-regulation of E-FABP mRNA and retraction of neurites. Immunofluorescence microscopy reveals E-FABP immunoreactivity in the perinuclear cytoplasm, neurites and growth cones of NGF-differentiated cells. To examine the role of E-FABP during neurite outgrowth, PC12 cells were transfected with a constitutive antisense E-FABP vector to create the E-FABP-deficient line PC12-AS. By morphometric analysis, PC12-AS cells treated for 2, 4, and 7 days with NGF exhibited significantly decreased neurite expression relative to control (mock-transfected) cells. Taken together, these data indicate that E-FABP is important in normal NGF-mediated neurite outgrowth in PC12 cells, a finding that is consistent with a potential role in axonal development and regeneration.

The preparation, characterisation, and DNA adduct profile of 2-amino-2-methyl-3-butanoneoximedichloroplatinum(II), a platinum(II) complex designed to bind to GpA sequences of DNA

The complex, 2-amino-2-methyl-3-butanoneoximedichloroplatinum(II), [Pt(ambo)Cl2], was chosen because of its potential to bind to GpA sequences of duplex DNA. Crystals of [Pt(ambo)Cl2] are monoclinic, space group, P2(1)/n, a = 6.799(4), b = 17.642(5), c = 8.193(2) A, beta = 102.10(3) degrees, Z = 4, R = 0.033 (1864 F). The binding of [Pt(ambo)Cl2] to salmon-sperm DNA was studied using enzymatic digestion and HPLC analysis. [Pt(ambo)Cl2] was found to form fewer GpG and ApG intrastrand adducts and more monofunctional adducts than [Pt(en)Cl2]. Binding to GpA sequences could not be established, but [Pt(ambo)Cl2] forms substantially more adducts with adenine than does [Pt(en)Cl2].

The Dichloroplatinum(II) and Dichloropalladium(II) Complexes of 1,4-Diazacycloheptane: Preparative, Structural and Conformational Studies

The preparation and purification of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] ( hpip = homopiperazine = 1,4-diazacycloheptane) are described. Crystal structures of [Pt( hpip )Cl2] and [Pd( hpip )Cl2] have been determined by X-ray diffraction methods and refined to R values of 0.023 (932 F) and 0.023 (948 F). The crystals of [Pt( hpip )Cl2] are orthorhombic, space group Pbcm , a 7.7019(8), b 9.8080(12), c 12.1944(14) Ǻ, and those of [Pd( hpip )Cl2] are monoclinic, space group P21/m, a 6.1001(9), b 11.527(2), c 6.458(I) Ǻ, β 106.30(2)°. The seven- membered rings of the ligands in both complexes adopt boat-like conformations in which the five- membered chelate ring has an eclipsed N-C-C-N group and the six- membered chelate ring adopts a chair conformation. Molecular mechanics methods were used to investigate whether this conformation was a crystallographic artefact but it was found to be real. An alternative conformation in which the six-membered chelate ring adopts a skew-boat conformation was also investigated. It was found to be less stable than the conformation observed in the crystal structures, but to a degree that depends on whether non-bonded interactions involving the metal atom were included or not.

Fluid flow in the cochlear aqueduct and cochlea-hydrodynamic considerations in perilymph fistula, stapes gusher, and secondary endolymphatic hydrops

There is convincing evidence that the cochlear aqueduct is normally patent in humans and is of relatively constant size. It probably plays an important role in the balance between the perilymphatic, endolymphatic, and cerebrospinal fluid pressures. The flow rate of liquids through tubes is a linear function of pressure, viscosity, and length of the tube but is a fourth degree power function of the radius of the lumen. For this reason, the radius is the most critical factor determining the flow rate. Small variations in size of the cochlear aqueduct can cause very large variations in flow rate through it.

Anisotropic Polarizabilities of Tin(IV)-Containing Groups

Electric birefringences , dipole moments and refractivities are reported for a series of organotin compounds. From these are deduced molecular polarizability anisotropies which, with data from Raman band intensities, can be dissected to give the anisotropic polarizabilities for component tin-containing groups. The results fit reasonably within a 'valence-optical' scheme of group polarizability additivity. Regular trends are observed in the directional polarizabilities of groups containing the Group 4b elements Si, Ge and Sn.

Bilateral blind epithelized tracts associated with the inferior labial frenum

Examination of a 45-year-old man disclosed, bilateral, blind, epithelium-lined tracts on the alveolar mucosa in proximity to the inferior labial frenum. These structures were excised surgically and examined histologically. This article represents the first report of blind mucosal pits in this location. The mechanism responsible for development of these structures is not clear, but they most likely result from entrapment or persistence of epithelium during embryogenesis.

Clinical implications of experiments on alteration of the labyrinthine fluid pressures

Hearing is affected by changes in hydrostatic pressure of the perilymph, but very high pressures are required to produce a significant loss. Among the observed findings in cats are a rapidly reversible decrease in the sensitivity of the cochlear microphonic that is greater for low frequencies, harmonic distortion and reduction of dynamic range as measured by the input-output function for the cochlear microphonic, and a change in the summating potential from negative to positive. These changes are attributed to a temporary reduction in the size of the cochlear duct due to a shift of water molecules out of the cochlear duct into the blood until the resulting increase in osmotic pressure balances the increase in hydrostatic pressure. Consequently, the organ of Corti is biased "upward" away from the scala tympani. Increasing the hydrostatic pressure of the endolymph produces a "downward" biasing of the organ of Corti and has an opposite effect upon the summating potential. Presumably this is what happens in Meniere's disease. Because of the presence of the perilymphatic canaliculi, the locus of the hydrostatic pressure effect is assumed to be in the region of the reticular lamina. A theory has been developed to explain why cochlear function is very sensitive to relative differences between the hydrostatic pressures of the perilymph and the endolymph but is resistant to large variations in the absolute magnitudes of those pressures. Some of the clinical implications of this theory are discussed.

Human laryngeal reinnervation: the Northwestern experience

Recent publications have reported impressive success with laryngeal reinnervation utilizing a nerve-muscle pedicle. This innovative surgical procedure is claimed to be useful for unilateral and bilateral vocal cord paralysis. Although the surgical results reported by Tucker have been good, they have lacked corroboration from other centers. We have performed six laryngeal reinnervation procedures at Northwestern University Medical School. Four patients presented with bilateral vocal cord paralysis and two patients with unilateral paralysis. All six operations were successful in restoring vocal cord function. The technique, problems, and results are discussed. Our experience supports the initial reports of success with this new operation.

Clinical investigation of a new intravenous anesthetic--etoxadrol hydrochloride (CL-1848; U-37862A)

Twenty-eight patients were anesthetized with etoxadrol as primary agent. The anesthesia produced was characterized by profound analgesia and amnesia, while pharyngeal and laryngeal reflexes, as well as swallowing and lid reflexes, remained active. Systolic, diastolic, and pulse pressure were slightly increased, with associated tachycardia and tachypnea. A dose of 0.75 mg/kg produced anesthesia for an average of 26 (14 to 53) minutes. Alternating nystagmus was present for several hours and associated with dreams and/or visions that were pleasing to most patients. Six patients, however, had unpleasant dreams for up to 24 hours. One patient given an excessive dose (4.65 mg/kg) was cataleptic, amnesic, and analgesic for 6 days. The occurrence of unpleasant dreams and aberrations in over 20% of the patients suggests that the drug probably has little usefulness in anesthesia. However, the extreme safety of the drug (an LD50 equal to some 20 to 40 times the ED50) and the prolonged analgesia justified clinical testing. There was no evidence of metabolic or systemic organ system change from any of the clinical laboratory studies.

Studies on phosphorylation by phosphoroguanidinates. The mechanism of action of creatine: ATP transphosphorylase (creatine kinase)

The solvolyses of phosphorocreatine (creatine phosphate) and models for phosphorocreatine have been investigated and the results are applied to the mechanism of action of creatine kinase (EC 2.7.3.2). A metaphosphate intermediate appears to be involved.

Acute Atypical Bovine Pneumonia Caused by Ascaris Lumbricoides

A case of acute atypical pneumonia (bovine asthma, pulmonary emphysema, or pulmonary adenomatosis) occurred in a group of cross-bred beef type yearlings in late autumn. Clinical signs included a forced expiratory grunt, excessive salivation, ruminal stasis and, on auscultation over the lungs, pulmonary emphysema and oedema. The cattle had been brought in from a poor summer pasture and housed in a pig pen heavily contaminated with Ascaris lumbricoides eggs as it had contained unwormed feeder pigs all summer. Fifteen out of seventeen head were affected ten days following housing and all within twenty-four hours. One steer of the group died and at necropsy fourth stage A. lumbricoides larvae were isolated from lungs showing profuse oedema and some emphysema. Histopathological examinations of the lungs showed a diffuse interstitial pneumonia. All remaining animals appeared clinically normal six days following the outbreak.