To thin or not to thin: the use of the anterolateral thigh flap in the reconstruction of intraoral defects.

The anterolateral thigh (ALT) flap has achieved popularity recently for free-flap reconstruction of intraoral defects following excision of squamous cell carcinoma. We have assessed the feasibility of the ALT flap as a free flap for oral lining and the potential use of the thinned ALT flap in a one-stage reconstruction. We used the ALT flap to reconstruct the oral cavity in 18 consecutive patients between December 2000 and December 2001 following intraoral resection of squamous cell carcinoma. Twelve patients underwent reconstruction using a standard ALT flap, four patients received a thinned ALT flap in a one-stage procedure, one patient received a standard ALT flap in combination with a fibula flap and one patient received a combination of a standard ALT flap and vascularised iliac bone. There were no complications in any of the 14 cases in which a standard ALT flap was used. Two of these flaps were thinned subsequently as secondary procedures. Of the four thinned ALT flaps, one flap failed completely and two flaps experienced partial necrosis. In all but one case the donor site was closed directly with minimal donor-site morbidity. The ALT flap is a versatile flap that can be used in combination with other flaps for more complex defects with minimal donor-site morbidity and is a useful alternative in the armamentarium of the head and neck surgeon. Thinning of the flap is best performed as a secondary procedure, should it be required.     

Developmental patterns of intermediate filament gene expression in the normal hamster brain

We have examined the patterns of expression of the major intermediate filament (IF) protein mRNAs during development of the hamster brain. Quantitative northern blotting was used to examine changes in the levels of mRNAs for the low, middle and high molecular weight neurofilament proteins (NF-L, NF-M, NF-H) as well as peripherin, vimentin and glial fibrillary acidic protein (GFAP). Total RNA was isolated from hamster brains at embryonic (E) days 12 and 14 and postnatal (P) days 1, 3, 5, 7, 9, 11, 13, 15, 20, 28 and 60-90 (adult), and probed with specific IF cDNAs. Northern blotting revealed that NF-L and NF-M mRNAs were present at very low levels in embryonic brain and that significant expression of these genes only occurred postnatally when the levels increased dramatically until P28 and then declined again in the adult. Increases in NF-H mRNA levels were somewhat delayed relative to those of NF-L and NF-M. NF-H mRNA was not seen at embryonic stages and was expressed at very low levels prior to P9; after that time the levels increased rapidly until P28 and then declined in the adult. Two of the type III IF genes, peripherin and vimentin, followed a pattern of expression opposite that of the NF genes. Both peripherin and vimentin mRNAs were present in embryonic brain and were expressed at higher levels during early postnatal stages than at later times. The magnitude and rate of reduction in vimentin gene expression in the postnatal interval was much greater than that of peripherin. GFAP mRNA levels were extremely low prior to P9 after which a robust increase occurred, followed by a decline in the adult. We discuss the implication of the dramatic changes in IF isotype expression in brain to the pathways of both neuronal and glial development in vivo.     

Effect of the development of portosystemic shunts in the maintenance of portal hypertension in rats

We studied the role of portosystemic shunt development in the maintenance of portal hypertension in a prehepatic portal hypertension rat model. A first group was studied two days after partial portal vein ligation. When portosystemic shunts were negligible; the second group was studied 3 weeks after the partial portal vein ligation, when large portosystemic shunts were present. Portal pressure was significantly higher in the first group than in the second group (19.9 +/- 0.8 mmHg (mean +/- 1 SD) and 12.8 +/- 2.3 mmHg, respectively; p less than 0.001). When compared with sham operated rats: a) portal tributary blood flow (measured with the radioactive microspheres method) was decreased in the first group (- 34 p. 100; p less than 0.01) and increased in the second group (+ 32 p. 100; p less than 0.02); b) portal system vascular resistance was markedly increased in the first group (+ 269 p. 100; p less than 0.001) and did not significantly change in the second group (+ 30 p. 100). These results suggest that portosystemic shunt development decreases portal pressure but not to normal value because portal tributary blood flow is increased. Moreover the increase in portal system vascular resistance and in portal tributary blood flow play different roles in the maintenance of portal hypertension depending on the stage of evolution of portal hypertension.     

Malignant ovarian mixed germ cell tumour: a rare combination

Ovarian germ cell tumours are very rare and affect mainly young girls and women. Due to this, the conservation of reproductive potential is of great concern. One of the most remarkable advances in oncology is in the treatment of malignant ovarian germ cell tumours. Two histological groups are distinguished: dygerminomas, equivalent to testicular seminomas, and non-dysgerminomatous tumours. We report a case of a 30-year-old nulliparous woman who presented with persistent per vaginal bleeding and was found to have a malignant mixed germ cell tumour comprising of both embryonal carcinoma and choriocarcinoma.     

Lung preservation solution substrate composition affects rat lung oxidative metabolism during hypothermic storage

Lungs harvested for transplantation utilize oxygen after procurement. We investigated the effects of storage solution substrate composition on pulmonary oxidative metabolism and energetics during the preservation interval. Rat lungs were harvested and stored at 10 degrees C in low-potassium dextran (LPD) solution. Groups of lungs were preserved with preservation solution containing 5mM carbon-13 ((13)C) labeled glucose or increasing concentrations of (13)C labeled pyruvate. Additional groups of rat lungs were studied with dichloroacetate (DCA) added to the pyruvate-modified preservation solutions. Oxidative metabolism (measured by (13)C-enrichment of glutamate) and adenine nucleotide levels were quantified. Increasing preservation solution pyruvate concentration augmented glutamate (13)C-enrichment up to a concentration of 32mM pyruvate. DCA further stimulated oxidative metabolism only at lower concentrations of pyruvate (4 and 8mM). ATP and ADP were not different among groups, but AMP levels were higher in the glucose group. These data suggest that altering the substrate composition of the preservation solution influences lung metabolism during allograft preservation for transplantation.     

Functional organization of enhancer (ENII) of hepatitis B virus.

A new enhancer ENII, located in the X open reading frame and immediately upstream of the core gene promoter, has recently been identified in the genome of hepatitis B virus. We have studied the functional constituents of this new enhancer in different cell lines. ENII can be divided into two functional elements, A and B, corresponding to two major binding sequences for nuclear protein factors. Element A alone gave very low activity; however, it was a modulatory element important for cell-type specificity. Element B was shown to be the basic functional element of ENII, which retained about 70% of the enhancer activity of the complete ENII in HepG2 cells. Element B can be further dissected into three subunits, B1, B2, and B3, which act synergistically. A 52-bp sequence is identified as the core sequences of element B. A model for the mechanism of ENII function is proposed.