Immediate lengthening temporalis myoplasty for facial palsy reconstruction following facial nerve inclusive total parotidectomy.

Immediate lengthening temporalis myoplasty (Labbé procedure) for immediate dynamic facial reanimation after nerve-inclusive parotidectomy in the elderly population is undocumented in the literature. The aim of this work was to determine whether the Labbé approach could achieve immediate, good functional and static results in elderly patients with acquired facial palsy. A retrospective analysis of five patients with parotid malignancies involving the facial nerve who underwent parotidectomy and an immediate Labbé procedure was performed. The House-Brackmann and Sunnybrook scores for facial palsy were used as objective measurements of the functional outcome. All patients underwent total parotidectomy, neck dissection, Labbé procedure, immediate temporary tarsorrhaphy, brow lift, and postoperative radiotherapy. Mean patient age was 83 (range 73-87) years. The average resected tumour size was 3.54 cm. The mean duration of surgery was 324 min and length of hospital stay 4 days. All patients experienced an improvement in House-Brackmann of one grade postoperative (grade V to IV in four, grade VI to V in one); the Sunnybrook score improved by 31 points on average (mean preoperative 3.8 vs postoperative 34.8). An immediate Labbé procedure following ablative parotid malignancy resection is a reliable and safe reconstructive procedure in a carefully selected elderly population, providing acceptable immediate static and dynamic hemifacial mimetic function and eliminating an additional facial palsy correction procedure.

Effects of thymic factors on growth of experimental tumors.

The effects of thymic factors on the growth of a chemically induced tumor have been studied. The thymic factors were obtained by a gentle isolation procedure which minimizes loss of material and biological activity. The administration of the thymic factors neither influenced the development or growth of the tumor nor the weight of the thymus or the spleen. A bigger thymus and a smaller spleen were observed in animals rejecting the tumor, whether or not they received the thymic factors.

Chromatographic isolation of thymic factors impairing neuromuscular transmission.

Thymopoietins I and II are chemically related peptides able to inhibit neuromuscular transmission. They were first isolated from bovine thymus by a protein-denaturating method, which may have destroyed other thymic factors displaying the same biological activity. The present investigation, based on a new gentle isolation procedure, suggests that thymopoietins are the only factors impairing neuromuscular transmission that are present in the thymus. The yield of the new procedure is at least twice as high as that of the original method.

Serum thymic factor and the neuromuscular transmission.

The effect of Serum Thymic Factor (FTS) on neuromuscular transmission has been studied in vivo by electromyographic assay. As no modification of muscle tetanus pattern was detected, the involvement of this factor in the pathology of thymus disorders leading to myasthenia is unlikely.

Specific interactions of 3-phosphoglyceroyl-glyceraldehyde-3-phosphate dehydrogenase with coenzymes.

The binding of oxidized and reduced coenzyme (NAD+ and NADH) to 3-phosphoglyceroyl-glyceraldehyde-3-phosphate dehydrogenase has been studied spectrophotometrically and fluorimetrically. The binding of NAD+ to the acylated sturgeon enzyme is characterized by a significant quenching of the enzyme fluorescence (about 25%) and the induction of a difference spectrum in the ultraviolet absorbance region of the enzyme. Both of these spectroscopic properties are quantitatively distinguishable from those of the corresponding binary enzyme-NAD+ complex. Binding isotherms estimated by gel filtration of the acylated enzyme are in close agreement to those obtained by spectrophotometric and fluorimetric titrations. Up to four NAD+ molecules are bound to the enzyme tetramer. No anticooperativity can be detected in the binding of oxidized coenzyme, which is well described on the basis of a single class of four binding sites with a dissociation constant of 25 muM at 10 degrees C, pH 7.0. The binding of NADH to the acylenzyme has been characterized spectrophotometrically. The absorption band of the dihydronicotinamide moiety of the coenzyme is blue-shifted to 335 nm with respect to free NADH. In addition, a large hypochromicity (23%) is observed together with a significant increase of the bandwidth at half height of this absorption band. This last property is specific to the acylenzyme-DADH complex, since it disappears upon arsenolysis of the acylenzyme. The binding affinity of NADH to the acylated enzyme has been estimated by performing simultaneous spectrophotometric and fluorimetric titrations of the NADH appearance upon addition of NAD+ to a mixture of enzyme and excess glyceraldehyde 3-phosphate. In contrast to NAD+, the reduced coenzyme NADH appears to be relatively strongly bound to the acylated enzyme, the dissociation constant of the acylenzyme-NADH complex being estimated as 2.0 muM at 25 degrees C. In addition a large quenching of the NADH fluorescence (about 83%) is observed. The comparison of the dissociation constants of the coenzyme-acylenzyme complexes and the corresponding Michaelis constants suggests a reaction mechanism of the enzyme in which significant formation and dissociation of NAD+-acylenzyme and NADH-acylenzyme complexes occur. Under physiological conditions the activity of the enzyme can be regulated by the ratio of oxidized and reduced coenzymes. Possible reasons for the lack of anticooperativity in coenzyme binding to the acylated form of the enzyme are discussed.

Sturgeon glyceraldehyde-3-phosphate dehydrogenase.

The formation of binary complexes between sturgeon apoglyceralddhyde-3-phosphate dehydrogenase, coenzymes (NAD+ and NADH) and substrates (phosphate, glyceraldehyde 3-phosphate and 1,3-bisphosphoglycerate) has been studied spectrophotometrically and spectrofluorometrica-ly. Coenzyme binding to the apoenzyme can be characterized by several distinct spectroscopic properties: (a) the low intensity absorption band centered at 360 nm which is specific of NAD+ binding (Racker band); (b) the quenching of the enzyme fluorescence upon coenzyme binding; (c) the quenching of the fluorescence of the dihydronicotinamide moiety of the reduced coenzyme (NADH); (D) the hypochromicity and the red shift of the absorption band of NADH centered at 338 nm; (e) the coenzyme-induced difference spectra in the enzyme absorbance region. The analysis of these spectroscopic properties shows that up to four molecules of coenzyme are bound per molecule of enzyme tetramer. In every case, each successively bound coenzyme molecule contributes identically to the total observed change. Two classes of binding sites are apparent at lower temperatures for NAD+ Binding. Similarly, the binding of NADH seems to involve two distinct classes of binding sites. The excitation fluorescence spectra of NADH in the binary complex shows a component centered at 260 nm as in aqueous solution. This is consistent with a "folded" conformation of the reduced coenzyme in the binary complex, contradictory to crystallographic results. Possible reasons for this discrepancy are discussed. Binding of phosphorylated substrates and orthophosphate induce similar difference spectra in the enzyme absorbance region. No anticooperativity is detectable in the binding of glyceraldehyde 3-phosphate. These results are discussed in light of recent crystallographic studies on glyceraldehyde-3-phosphate dehydrogenases.