Microlaparoscopy in sex reassignment surgery

Sex reassignment (male to female surgery) is a standard operation which is aimed at constructing female genitalia and obtaining a cosmetic and functional result that is similar to that of a normal female subject. The ideal surgical procedure has not yet been described, but the various techniques which have been proposed in the literature are similar. The most cumbersome maneuver of the procedure is that of creating a neovaginal cavity inside the perineum. This step is generally carried out by means of blunt dissection between the rectal wall and the prostate, but most of the surgery is blindly performed without visual control. In these conditions, the risk of rectal injury is high, and may lead to severe intraoperative complications. Microlaparoscopy allows for a direct observation of the perineal dissection from inside the peritoneal cavity, thus avoiding risk of rectal injury. The technique is simple to perform, is non-invasive, and only 15 minutes are added to the operation.     

A novel MaxiK splice variant exhibits dominant-negative properties for surface expression

We identified a novel MaxiK alpha subunit splice variant (SV1) from rat myometrium that is also present in brain. SV1 has a 33-amino acid insert in the S1 transmembrane domain that does not alter S1 overall hydrophobicity, but makes the S0-S1 linker longer. SV1 was transfected in HEK293T cells and studied using immunocytochemistry and electrophysiology. In non-permeabilized cells, N-terminal c-Myc- or C-terminal green fluorescent protein-tagged SV1 displayed no surface labeling or currents. The lack of SV1 functional expression was due to endoplasmic reticulum (ER) retention as determined by colabeling experiments with a specific ER marker. To explore the functional role of SV1, we coexpressed SV1 with the alpha (human SLO) and beta1 (KCNMB1) subunits of the MaxiK channel. Coexpression of SV1 inhibited surface expression of alpha and beta1 subunits approximately 80% by trapping them in the ER. This inhibition seems to be specific for MaxiK channel subunits since SV1 was unable to prevent surface expression of the Kv4.3 channel or to interact with green fluorescent protein. These results indicate a dominant-negative role of SV1 in MaxiK channel expression. Moreover, they reveal down-regulation by splice variants as a new mechanism that may contribute to the diverse levels of MaxiK channel expression in non-excitable and excitable cells.     

L-Fucose Is a Potent Inhibitor of myo-Inositol Transport and Metabolism in Cultured Neuroblastoma Cells

It has been proposed that abnormal myo-inositol metabolism may be a factor in the development of diabetic complications. Studies with animal models of diabetes and cultured cells have suggested that hyperglycemia by an unknown mechanism may alter myo-inositol metabolism and content. Recently, we have shown that L-fucose, a 6-deoxy sugar whose content has been reported to be increased in diabetes, is a potent inhibitor of myo-inositol transport. To examine the effect of L-fucose on myo-inositol metabolism, neuroblastoma cells were cultured in medium supplemented with L-fucose. L-Fucose is a competitive inhibitor of Na(+)-dependent, high-affinity myo-inositol transport. The Ki for inhibition of myo-inositol transport by L-fucose is about 3 mM. L-Fucose is taken up and accumulates in neuroblastoma cells. The uptake of L-fucose is inhibited by Na+ depletion, D-glucose, glucose analogues, phloridzin, and cytochalasin B. In contrast, neither myo-inositol nor L-glucose inhibits L-fucose uptake. Chronic exposure of neuroblastoma cells to 1-30 mM L-fucose causes a decrease in myo-inositol accumulation and incorporation into inositol phospholipids, intracellular free myo-inositol content, and phosphatidylinositol levels. Na+,K(+)-ATPase transport activity is decreased by about 15% by acute or chronic exposure of neuroblastoma cells to L-fucose. Similar defects occur when neuroblastoma cells are exposed chronically to 30 mM glucose. Cell myo-inositol metabolism and Na+/K(+)-pump activity are maintained when 250 microM myo-inositol is added to the L-fucose-supplemented medium. Unlike the effect of chronic exposure of neuroblastoma cells to medium containing 30 mM glucose, the resting membrane potential of neuroblastoma cells is not altered by chronic exposure of the cells to 30 mM L-fucose. The effect of L-fucose on cultured neuroblastoma cell properties occurs at concentrations of L-fucose which may exist in the diabetic milieu. These data suggest that increased concentrations of L-fucose may have a role in myo-inositol-related defects in mammalian cells.     

INCREASED INCORPORATION OF [G-3H]LEUCINE INTO A POSSIBLE ''RECEPTOR'' PROTEOLIPID IN DENERVATED MUSCLE IN VIVO

Abstract— The incorporation of radioactive leucine into the total proteins and the proteolipids of normal and denervated rat diaphragm has been studied in vivo. Denervation increased the incorporation of isotopically labelled leucine into each of the isolated proteolipids and the effect was particularly marked in a single proteolipid which has been designated a 'receptor' proteolipid. In normal muscle this particular proteolipid was found to have a higher incorporation of isotopically labelled leucine in the area of the muscle rich in endplates compared with an area devoid of endplates. However the stimulatory effect of denervation on the incorporation of radioactive leucine into this proteolipid was considerably more marked in the latter region. An attempt has been made to correlate these findings with the development of the hypersensitivity to ACh characteristic of denervated muscle.     

Preparation and some properties of a dimeric form (S-S) of horse muscle acylphosphatase.

The use of sodium selenite as a catalyst in the presence of oxygen was a suitable technique to obtain in good yield an interchain S-S dimeric form of horse muscle acylphosphatase. The dimer so obtained possesses kinetic properties very similar to those of the native enzyme. On the other hand the dimer has shown a generally lower stability in respect of the thermal inactivation, particularly in the acidic environment, to the lyophilization and to the proteolytic attack. As regards the 8 M urea inactivation, the dimer is not able to completely regain its activity by dilution, showing a behaviour quite different from that of the native enzyme.