Delayed chest wall complications of median sternotomy.

Chest wall pain after coronary artery bypass surgery is often attributed to incisional pain or anxiety. Although this assumption is often correct, a small number of patients have an unrecognized chest wall complication of the median sternotomy. In this paper we identify these delayed postoperative midsternotomy complications and discuss their appropriate management.

Persistent chest pain due to sternal wire sutures: a complication of coronary artery bypass surgery.

Disabling incisional pain weeks or months after coronary artery bypass surgery should prompt an investigation for a postmidsternotomy chest wall complication. Our patient had symptomatic relief after the removal of a painful sternal wire suture. Prompt recognition of this delayed chest wall complication, which can be confused with cardiac pain, may obviate a more lengthy and costly evaluation.

Characterization of crystals of protocatechuate 3,4-dioxygenase from Pseudomonas cepacia.

Protocatechuate 3,4-dioxygenase (EC 1.13.11.3) from Pseudomonas cepacia (Mr = 198,000) has been crystallized from potassium phosphate at pH 7.5. Of the two orthorhombic forms that have been characterized, one contains a single molecule of tetrameric protocatechuate dioxygenase, (alpha beta Fe3+)4, per asymmetric unit. The space group and cell dimensions for this form are: P2(1)2(1)2(1) with a = 125.9 A, b = 161.7 A, and c = 85.2 A.

Influence of triazolam on thermal heat balance in poor sleepers.

The influence of a benzodiazepine (triazolam) on the body temperature of poor sleepers during nights disturbed by airplane noises has been examined. Subjects were divided into 3 groups each of 8 men. Following a double-blind design, Group A (controls) received a placebo for 6 consecutive nights, Group B received 0.25 mg triazolam, and Group C received 0.5 mg triazolam on nights N3, N4 and N5. On all other nights Group B and C subjects received placebo. For all 3 groups, nights N3 and N5 were disturbed by 32, semi-randomly distributed airplane noises. Air and wall temperatures (To = 20 degrees C), and air humidity (Tdp = 10 degrees C), were kept constant. Rectal temperature and 4 local skin temperatures were recorded from each subject. Urine samples were collected each morning for measurement of cortisol and catecholamine levels. Noise was found to cause an increase in body heat storage, but only in Group A. Both drug groups showed impairment of body heat balance. The hypothermic action of triazolam could be explained both by a central action of the drug on the thermoregulatory controller and by a peripheral action on blood vessels.

Characteristics of rapid eye movement production during REM sleep in man: organization and rhythmicity.

The purpose of this study was to verify statistically the existence of certain characteristics of rapid eye movement (REM) production during REM sleep: organization and rhythmicity. REM data were collected intermittently, over a period of 20 consecutive nights, from 6 normal adult subjects of both sexes. Results concerning the organization of REM production revealed the presence of 3 evolving slow trends: quadratic, linear and quasi-sinusoidal. The occurrence of a given trend type was not related to subject, night, time of night or length of REM sleep phase being analysed. Results of the analysis showed that it is possible for a series of REMs to contain one, two or more statistically significant rhythmic periods, or no significant rhythmic period. The rhythmic periods that were detected ranged from 1 to 21 min, and no predominant periods were present. As in the case of the slow trends, the occurrence of a given rhythmic period was not dependent on subject, night, time of night or length of the REM sleep phase.

Comparison of transfer ribonucleic acid structures using cobra venom and S1 endonucleases.

Cobra venom nuclease V1, which cleaves double-stranded RNA, has been used to study the structure of four Escherichia coli tRNAs: Phe, Glu2, Leu2, and Ile1. The cleavage patterns are compared to those found for yeast tRNAPhe, the three-dimensional structure of which is known. The cleavage patterns of all the tRNA molecules are similar, and the most sensitive cleavage is found at the central base pair of the anticodon stem. Studies of E. coli tRNALeu2, which has a large variable loop, are consistent with the formation of a base-paired stem and loop structure that is not closely bound to the remainder of the molecule. A survey of the results suggests that the V1 molecule may interact with the minor groove of the double helix with an affinity for stacked bases and that it may require two or three stacked bases for optimal binding and cleavage.

Interaction of alpha-chymotrypsin with the fluorescent probe 1-anilinonaphthalene-8-sulfonate in solution.

The binding of the fluorescence probe 1-anilinonaphthalene-8-sulfonate (Ans) to alpha-chymotrypsin (alpha-CHT) at pH 3.6 is accompanied by a dramatic enhancement of Ans fluorescence and a shift of the emission maximum to shorter wavelengths. Our study reveals that one Ans molecule binds to alpha-CHT at a site different from either the active site of alpha-CHT or the 2-p-toluidinylnapthalene-6-sulfonate binding site. the binding constant of Ans is about the same (10(4) M-1) at pH 3.6 and 6.4. Nanosecond fluorescence depolarization data indicate that Ans is rigidly bound to alpha-CHT. The fluorescence enhancement due to binding of Ans to alpha-CHT at low pH could be due to binding either to a hydrophobic site or to a site where local dipoles do not relax during the excited-state lifetime of Ans. As the pH is increased, fluorescence intensity of the Ans-alpha-CHT complex decreases appreciably; and the emission maximum shifts to longer wavelengths. The fluorescence decay curves exhibit a corresponding sensitivity to pH. The pH effect on the fluorescence of Ans-alpha-CHT can be interpreted in terms of a pH-dependent equilibrium between alpha-CHT conformers differing in the degree of mobility of polar residues and water molecules at the Ans binding site or structural changes in the Ans binding site.