Complete separation of lipid classes on a single thin-layer plate

A double-development procedure employing first a polar and then a nonpolar solvent system is described for the complete separation by thin-layer chromatography of the main lipid classes encountered in natural lipids. For better quantification, long plates (34 cm) are employed. Diglycerides were separated from cholesterol, 1,2- from 1,3-diglycerides, and monoglycerides from phospholipids.     

A generalized theory of particulate electron conduction enzymes applied to cytochrome oxidase. A theory of coupled electron and/or ion transport applied to pyruvate carboxylase

A previously developed theory of particulate electron conduction enzymes was based on a model of an enzyme particle catalyzing the oxidation-reduction of two different substrates at two different enzymatic sites on the same particle with conduction of electrons between the two sites through the enzyme particle. Using the simplifying assumption that the percent reduction of the second substrate is held constant, there was previously shown to be a hyperbolic relationship between the first order rate constant (k′) and the sum (C _x ) of oxidized plus reduced substrate, of the formk′=α/(C _x +β), where α and β are positive constants. It is shown here that if this simplifying assumption is omitted, a positive constant is added to the right hand side of this equation, which describes exactly the experimental data of Smith and conrad on cytochrome oxidase. If electron transport is assumed to be coupled to ion transport, this equation becomesk′=(α/C _x )?γ (where γ is a positive constant) which describes the experimental data of Eadie and Gale on pyruvic carboxylase of yeast. It seems probable that the same theory is applicable to coupled ion-ion transport and coupled electron-electron transport in both membranous systems, and in particulate preparations consisting of membrane fragments.     

PSYCHOSURGERY—Present Indications and Future Prospects

Although the advent and widespread use of ataractic drugs has more or less eclipsed lobotomy as a method of dealing with severe psychotic states, variations and adaptations of the operation still can be used with benefit in certain pretty well defined circumstances.“Chemical lobotomy” and regressive electroshock bring about alterations in behavior superficially resembling those of lobotomy, but without the changes in personality that are the object of lobotomy. These desirable changes consist in increased extraversion, decreased preoccupation with self and decreased sensitivity to the opinions of others. With restricted operations, undesirable changes—the “frontal lobe syndrome”—do not occur.Operative failures are due to three main causes: (a) Preoperative emotional deterioration; (b) progress of the underlying disease; (c) relapse, possibly due to inadequate operation.Lobotomy is advisable if the patient does not show sustained improvement after a year of active treatment by other indicated means. The operation often represents the turning point in effective treatment. After the first year of ineffective treatment valuable time is being lost, with danger of fixation and deterioration. Then it is safer to operate than to wait.The future of psychosurgery lies in prompt application, in favorable patients, of selective operations that will reverse the trend of illness.There is particular need for further exploration of the temporal lobes in the hope of finding some procedure that will suppress hallucinations. Some 90 per cent of patients remaining in hospitals after psychosurgery are experiencing hallucinations. If these phenomena can be eliminated without producing serious personality defects, another large field for the application of psychosurgery will be opened.     

Transmembrane Pickets Connect Cyto- and Pericellular Skeletons Forming Barriers to Receptor Engagement

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Identification of a novel metabolite in phenanthrene metabolism by the fungus Cunninghamella elegans.

The metabolism of phenanthrene by the fungus Cunninghamella elegans was investigated. Kinetic experiments using [9-14C]phenanthrene showed that after 72 h, 53% of the total radioactivity was associated with a glucoside conjugate of 1-hydroxyphenanthrene (phenanthrene 1-O-beta-glucose). This metabolite was isolated by reversed-phase high-performance liquid chromatography and characterized by the application of UV absorption, 1H nuclear magnetic resonance, and mass spectral techniques. The results show that aromatic ring oxidation followed by glucosylation is a predominant pathway in the metabolism of the polycyclic aromatic hydrocarbon phenanthrene by C. elegans.     

Spatiotemporal frequency responses of cat retinal ganglion cells

Spatiotemporal frequency responses were measured at different levels of light adaptation for cat X and Y retinal ganglion cells. Stationary sinusoidal luminance gratings whose contrast was modulated sinusoidally in time or drifting gratings were used as stimuli. Under photopic illumination, when the spatial frequency was held constant at or above its optimum value, an X cell's responsivity was essentially constant as the temporal frequency was changed from 1.5 to 30 Hz. At lower temporal frequencies, responsivity rolled off gradually, and at higher ones it rolled off rapidly. In contrast, when the spatial frequency was held constant at a low value, an X cell's responsivity increased continuously with temporal frequency from a very low value at 0.1 Hz to substantial values at temporal frequencies higher than 30 Hz, from which responsivity rolled off again. Thus, 0 cycles X deg-1 became the optimal spatial frequency above 30 Hz. For Y cells under photopic illumination, the spatiotemporal interaction was even more complex. When the spatial frequency was held constant at or above its optimal value, the temporal frequency range over which responsivity was constant was shorter than that of X cells. At lower spatial frequencies, this range was not appreciably different. As for X cells, 0 cycles X deg-1 was the optimal spatial frequency above 30 Hz. Temporal resolution (defined as the high temporal frequency at which responsivity had fallen to 10 impulses X s-1) for a uniform field was approximately 95 Hz for X cells and approximately 120 Hz for Y cells under photopic illumination. Temporal resolution was lower at lower adaptation levels. The results were interpreted in terms of a Gaussian center-surround model. For X cells, the surround and center strengths were nearly equal at low and moderate temporal frequencies, but the surround strength exceeded the center strength above 30 Hz. Thus, the response to a spatially uniform stimulus at high temporal frequencies was dominated by the surround. In addition, at temporal frequencies above 30 Hz, the center radius increased.     

B7, a B-cell-restricted antigen that identifies preactivated B cells

After activation with antigen or mitogen, a number of cell surface proteins appear that are not expressed on resting B cells. To date, a number of B lineage restricted and associated activation antigens have been reported that appear at distinct intervals after in vitro activation. In this report, we describe a new B lineage restricted activation antigen (B7) that appears within 24 hr of in vitro stimulation. The expression of B7 antigen, which is detected on a minor subpopulation of B cells isolated from peripheral blood and lymphoid tissues, is strongly induced following stimulation with either anti-immunoglobulin or Epstein-Barr virus. In contrast, B7 was not detected on resting or activated T cells or monocytes. The B7 antigen was expressed on a subset of B cell lines and B cell neoplasms, but was not detected on leukemias and lymphomas of T cell or myeloid origin. B7 was distinguished from other B cell restricted and associated activation antigens by its unique pattern of expression on a variety of hemopoietic cell lines. The biochemical characterization of B7, that it is a single chain protein of 60 kDa, further distinguishes it from other B cell activation antigens. The functional importance of the B7 antigen was demonstrated when splenic B cells were fractionated into the B7+ and B7- populations. The peak of proliferation in response to anti-Ig, appeared earlier within the B7+ population. These studies suggest that B7 antigen identifies a subpopulation of B cells that are preactivated or primed in vivo, and have an accelerated response to subsequent activation via cross-linking of surface Ig.