Blood platelet uptake of serotonin in episodic aggression

Blood platelet uptake of 3H-serotonin (5HT uptake), a potential marker of serotonergic function, was determined in male outpatients with episodic aggression (n = 15) and in age- and sex-matched nonaggressive controls (n = 15). Correlations with rating scales of "impulsivity" (Barratt Impulsivity Scale, 10th revision) and "anger" (Spielberger Anger Expression Scale) were performed. Mean 5HT uptake was 18% lower in patients with episodic aggression. A significant negative correlation between % difference in platelet 5HT uptake and impulsivity score was observed, but the correlation between 5HT uptake and anger was not significant. These results support the hypothesis of disturbed serotonergic function in aggression and suggest that the primary relationship is in the "control" of aggression. The blood platelet may be useful in identifying impulsive subtypes.     

Detection of clustered gastrointestinal contractions in partial intestinal obstruction by surface vibration analysis.

Gastrointestinal contraction "clusters" with alternating quiescence occur in partial intestinal obstruction and are conventionally detected by intraluminal manometry. Surface Vibration Analysis (SVA), which is a noninvasive test, was evaluated in this study in experimental and clinical situations. In the experimental situation, former SVA was assessed against simultaneous manometry in two volunteers, in whom partial obstruction had been induced by intrajejunal balloon distension. Manometry showed typical contraction "clusters" with alternating quiescence, each of two to four minutes duration, in obstructed jejunum proximal to the balloon. The distal jejunum was inhibited. SVA showed a pattern of hyperactivity and quiescence corresponding to proximal jejunal activity. In the clinical situation, SVA recordings taken after a standard meal in nine patients with suspected chronic obstruction adhesive obstruction, (subsequently proven in seven patients and disproved in two), and 36 volunteers were compared. All patients with proved obstruction showed an SVA pattern of alternating hyperactivity and quiescence. This pattern was not observed in volunteers or nonobstructed patients.     

Plateau potentials evoked by climbing-fibre stimulation are restricted to the Purkinje cell dendrites of the cat

The present study investigated the duration of afterdepolarizations in Purkinje cell somata following climbing-fibre activation. Intracellular recordings revealed that, in cells with membrane potentials more negative than -50 mV and with normal spike-generating capabilities, climbing-fibre activation resulted in somatic responses with short afterdepolarizations. As the cell deteriorated and the resting membrane potential became more positive, the duration and form of the climbing-fibre response resembled the plateau potentials recorded from proximal dendrites. The absence of plateau potentials in undamaged Purkinje cell somata was confirmed by extracellular recording of test spike amplitudes following evoked climbing-fibre responses.     

A glass/silicon composite intracortical electrode array

A new manufacturing technique has been developed for creating silicon-based, penetrating electrode arrays intended for implantation into cerebral cortex. The arrays consist of a 4.2 mm×4.2 mm glass/silicon composite base, from which project 100 silicon needle-type electrodes in a 10×10 array. Each needle is approximately 1,500 μm long, 80μm in diameter at the base, and tapers to a sharp point at the metalized tip. The technique used to manufacture these arrays differs from our previous method in that a glass dielectric, rather than ap-n-p junction, provides electrical isolation between the individual electrodes in the array. The new electrode arrays exhibit superior electrical properties to those described previously. We have measured interelectrode impedances of at least 10¹³ Ω, and interelectrode capacitances of approximately 50 fF for the new arrays. In this paper, we describe the manufacturing techniques used to create the arrays, focusing on the dielectric isolation technique, and discuss the electrical and mechanical characteristics of these arrays.     

Characteristics of the 19S and 7S response to bacteriophage ΦX174 in the fowl

After intravenous injection of 10¹⁰ plaque forming particles of ØX174 bacteriophage into White Rock fowls, immune elimination began at 30 hours and viable phage was cleared from the circulation by 50–52 hours, the approximate time at which detectable antibody appeared. Little change was noted in the serum neutralizing activity in the interval from 44 to 217 days after injection, at which time the birds were reinjected with ØX174.

Sephadex Peak I (19S globulin) accounted for most of the early activity of the primary response. By Day 9 most of the activity had shifted to Peak II (7S globulin). In the secondary response, the shift had occurred by Day 4. Both 19S and 7S globulin fractions showed an increase in activity when compared to the same days of the primary response, but the 7S increase was proportionately greater.

All sera and serum fractions (whether 19S or 7S) were sensitive to reduction with 2-mercaptoethanol, but became, less sensitive during the course of immunization.

With regard to the production of 19S antibody, White Rock fowls showed a different response to the particulate antigen ØX174 compared with the response to injection of the soluble antigen, bovine serum albumin. There is evidence of immunological memory in the 19S response to ØX174.

     

Crosslink formation in porcine valves stabilized by dye-mediated photooxidation

Bovine pericardial and porcine valve materials stabilized by dye-mediated photooxidation have shown potential for bioprosthetic valve use. Previously, in vitro and in vivo stability of these materials was demonstrated through enzymatic, chemical, extraction, rat subcutaneous, and functional challenges. Here, we examine the stability of photooxidized porcine aortic valves through amino acid, crosslink, and hydrothermal isometric tension analysis. Photooxidation reduced intact histidine residues from 17.0 to 0 residues per 1000, indicating the photooxidative alteration of this amino acid. Diphenyl borinic acid-derivitized hydrolyzates of proteins were separated by high-performance liquid chromatography, which identified several amino acid crosslinks that appeared with photooxidation that were absent in untreated controls. Thermal relaxation analysis indicated a significantly higher (p < 0.0002) thermal stability for photooxidized porcine cusps than that of untreated controls, with mean relaxation times for untreated cusps of 14,000 +/- 4650 versus 22,900 +/- 2480 s for photooxidized cusps. In summary, porcine aortic valve tissue treated by dye-mediated photooxidation contains new chemical species and exhibits properties consistent with intermolecular crosslink formation, which explain the increased biostability of this material and its potential for use in bioprosthetic devices.     

Use of buccal cells collected in mouthwash as a source of DNA for clinical testing

CONTEXT: To maximize the participation rate in population genetic studies, alternatives to invasive whole blood collection are increasing. One such alternative is buccal epithelial cell collection, which, in contrast to venipuncture and finger sticks, is painless. Buccal cells, if collected and purified efficiently, offer an acceptable source for DNA to be used in research and clinical applications. OBJECTIVE: To develop a noninvasive sampling method for collecting cells for routine DNA testing in a clinical laboratory setting. DESIGN: Five factors were used to evaluate several brands of mouthwash: (1) compatibility with the DNA purification chemistry, (2) DNA yield, (3) DNA quality, (4) DNA stability at room temperature, and (5) mouthwash taste. Next, an optimization study was undertaken to maximize DNA yield. Finally, a validation study was undertaken with the optimized protocol to test a panel of 14 donors for DNA yield and performance and to test for the stability of DNA held in mouthwash. SETTING: Industrial research and development laboratory. RESULTS: Of 5 mouthwashes tested, Scope brand mouthwash received the highest overall ranking. The addition of proteinase K and glycogen to the protocol significantly enhanced DNA yields, with a test panel (n = 14) giving a range of 12 to 60 microg of DNA per donor. In a 4-week room temperature stability study, the DNA in mouthwash samples was found to be stable for at least 2 weeks. CONCLUSION: A clinically validated DNA purification chemistry was adapted to a noninvasive specimen collection method. This method used a commercially available mouthwash, Scope, to collect buccal epithelial cells for the preparation of high-quality DNA in high yield.