Hepatic artery ligation for hepatic vascular tumors with arteriovenous and arterioportal venous shunts in the newborn: successful management of two cases and review of the literature.

The authors report their experience with hepatic artery ligation in two newborns, as well as relevant findings from a literature review. A 2-day-old boy had progressive cardiac and respiratory difficulty. A firm liver was palpable, with an overlying thrill. Sonography and arteriography showed diffuse arteriovenous shunting in both liver lobes. Hepatic artery ligation provided remarkable hemodynamic and clinical improvement. Another boy was admitted 3 weeks after birth because of bilious vomiting with abdominal distension and bloody stools. Abdominal examination showed a large liver with a systolic bruit and thrill. X-rays showed cardiac enlargement and dilated bowel loops with air-fluid levels. Arteriography and sonography showed arteriovenous and arterioportal venous shunting. Laparotomy was performed, and a large vascular malformation was palpated in both liver lobes. The entire bowel was congested and cyanotic, but there were no signs of obstruction. This patient had acute portal hypertension imitating intestinal obstruction. Ligation of the hepatic artery improved the color of the bowel, and the thrill disappeared. Five and nearly 4 years after the operation, both boys are growing normally without medication or diet. Sonography showed almost complete resolution of the hemangiomas.

Improved aesthetics in breast reconstruction: modified mastectomy incision and immediate autologous tissue reconstruction.

A common detraction from the aesthetic results of breast reconstruction is the presence of a transverse mastectomy scar and the patch-like effect of the paler abdominal skin contrasting with the thoracic skin. The technique described involves a modified mastectomy approach in which the breast parenchyma and nipple are first mobilized through a periareolar incision and then removed, along with the axillary lymph nodes, through an axillary counter-incision. A de-epithelialized transverse rectus abdominis musculocutaneous flap is then used to fill the empty "skin brassiere," effectively replacing the glandular defect, and a small patch of skin is exteriorized to match the areolar defect. Excellent symmetry can be attained usually without having to manipulate the opposite breast. After nipple-areolar reconstruction, the breast looks quite normal without the usual stigmas of mastectomy. In 21 breast reconstructions performed since 1991, there has been no incidence of skin flap necrosis or local recurrence.

Delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase, the multienzyme integrating the four primary reactions in beta-lactam biosynthesis, as a model peptide synthetase.

ACV synthetase forms the tripeptide precursor of penicillins and cephalosporins from alpha-aminoadipate, cysteine, and valine. Catalytic sites for substrate carboxyl activation as adenylates, peptide bond formations, epimerization and release of the tripeptide-thioester are integrated in multifunctional enzymes of 405 to 425 kD. These have been characterized from several pro- and eukaryotic beta-lactam producers. Implications of these results for the thio-template mechanism of peptide formation are discussed, as well as the use of this multienzyme as a model system for enzymatic peptide synthesis.

Reversible inhibition of the proton pump bacteriorhodopsin by modification of tyrosine 64.

Five mol of lysine per mol of bacteriorhodopsin were modified with methylacetimidate. This treatment did not inactivate bacteriorhodopsin but prevented all lysines from subsequent reaction with diazotized sulfanilic acid. This reaction predominantly modified tyrosine 64 and light-induced proton translocation was abolished. Reduction of the mono(p-azobenzene sulfonic acid) tyrosine 64 to the corresponding 3-amino derivative with sodium dithionite led to complete reactivation of the proton translocation activity of bacteriorhodopsin. The relative location of tyrosines 26 and 64 and the COOH terminus on the two surfaces of the purple membrane was determined by incorporation into phospholipid vesicles, subsequent modification, and proteolytic treatment. The results obtained support the models proposed by Engelmann et al. (Engelman, D. M., Henderson, R. McLauchlan, A. D., and Wallace, B. A. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 2023-2027) and by Ovchinnikov et al. (Ovchinnikov, Yu. A., Abdulaev, N. G., Feigina M. Yu., Kiselev A. V., and Lobanov, N. A. (1979) FEBS Lett. 100, 219-224). Tyrosine 64 is located on the extracellular side of the membrane, whereas tyrosine 26 and the COOH terminus are located on the cytoplasmic side. Because specific nitration of tyrosine 26 also leads to inactivation of bacteriorhodopsin (Lemke, H. D., and Oesterhelt, D. (1981) Eur. J. Biochem. 115, 595-604), the results obtained demonstrate that amino acid residues located on both surfaces of the purple membrane are involved in proton translocation.