Regional dermolipectomy as treatment for sequelae of massive weight loss

Dermolipectomy is the most important procedure for treatment of the deformities engendered by massive weight loss. It remains the only treatment for excising redundant skin. Although liposuction is useful for removing fatty deposits without traditional surgical incisions, its application is limited by the ability of the skin to contract and conform to the newly sculpted figure. Thus liposuction may serve as an adjunct when treating the sequelae of weight loss but not as a primary procedure. In response to changing expectations, reconstructive surgeons have developed increasingly ingenious and specific dermolipectomy procedures to minimize or hide scars, lessen morbidity, and enhance function. Liposuction in combination with dermolipectomy has expanded the applicability of traditional procedures to a wider variety of patients. Surgical history, patient selection, surgical planning, a spectrum of regional dermolipectomy procedures, and potential complications are discussed herein.     

Is DNA destiny? A cure for cystic fibrosis

Cystic fibrosis (CF) remains an attractive target for cure by gene therapy. Results from several trials are reviewed in this article and have shown that mature airway epithelial cells are relatively resistant to gene transfer, that host immune responses determine the duration of transgene expression and define the toxicity, and that the efficiency of transfection remains low. Significant hurdles to the development of gene therapy remain, including the definition of efficacy endpoints, the ability to produce enough material, and the ability to dose the entire lung. Nonetheless, invaluable insights into CF and pulmonary biology have been gained in the gene therapy research effort.     

Partial activation of muscle phosphorylase by replacement of serine 14 with acidic residues at the site of regulatory phosphorylation

Phosphorylation of glycogen phosphorylase at residue Ser14 triggers a conformational transition that activates the enzyme. The N-terminus of the protein, in response to phosphorylation, folds into a 310 helix and moves from its location near a cluster of acidic residues on the protein surface to a site at the dimer interface where a pair of arginine residues form charged hydrogen bonds with the phosphoserine. Site-directed mutagenesis was used to replace Ser14 with Asp and Glu residues, analogs of the phosphoserine, that might be expected to participate in ionic interactions with the arginine side chains at the dimer interface. Kinetic analysis of the mutants indicates that substitution of an acidic residue in place of Ser14 at the site of regulatory phosphorylation partially activates the enzyme. The S14D mutant shows a 1.6-fold increase in Vmax, a 10-fold decrease in the apparent dissociation constant for AMP, and a 3-fold decrease in the S0.5 for glucose 1-phosphate. The S14E mutant behaves similarly, showing a 2.2-fold increase in Vmax, a 6-fold decrease in the apparent dissociation constant for AMP, and a 2-fold decrease in the S0.5 for glucose 1-phosphate. The ability of the mutations to enhance binding of AMP and glucose 1-phosphate and to raise catalytic activity suggests that the introduction of a carboxylate side chain at position 14 promotes docking of the N-terminus at the subunit interface and concomitant stabilization of the activated conformation of the enzyme. Like the native enzyme, both mutants show significant activity only in the presence of the activator, AMP. Full activation, analogous to that provided by covalent phosphorylation of the enzyme, likely is not achieved because of differences in the charge and the geometry of ionic interactions at the phosphorylation site.     

The production of intense atomic beams

Methods of producing multichannel capillary arrays in various materials for use as atomic beam forming devices are reviewed. The advantages of gas focusing arrays are considered. The theories of the flow of gas through a cylindrical tube are discussed. Completely general numerical and graphical results derived from Zugenmaier's theory are presented. Their use in designing gas beam systems is described. Data are presented in a convenient form for the experimentalist. Comparison of the numerical results with published experimental data is made. It is shown that, for most purposes, a capillary is best operated at an input pressure giving a mean free path which is less than 10% of the tube length. In an array, it is an advantage to have tubes of small diameter. With a focusing array, beam densities of up to 10¹⁴ atoms cm^?3 are predicted when the beam half width is 1°.     

Diversity of sequences in total and polyadenylated nuclear RNA from Drosophila cells

Complementary DNA was synthesized using polyadenylated nuclear RNA of cultured Drosophila cells as template. The kinetics of hybridization of this cDNA with nuclear RNA indicated that the complexity of this RNA population is five to ten times greater than that of cytoplasmic mRNA. The same difference in the fraction of DNA represented was obtained when nuclear and cytoplasmic RNA were hybridized with labeled unique sequence DNA. The fraction of the DNA sequences represented in total number of polyadenylated nuclear RNA is much higher than that represented in cytoplasmic RNA.     

Bioplast fibrin buttons for liver biopsy and partial hepatic resection

Absorbable buttons made from fibrin (Bioplast buttons) have been used to facilitate liver biopsy or to control haemorrhage from the liver in 3 dogs and 14 patients. The buttons are easy to use, effective, and readily absorbed.     

Control of the delayed outward potassium currents in bursting pace-maker neurones of the snail, Helix pomatia

The net outward current in bursting pace-maker neurones of the snail (Helix pomatia) during sustained and repeated voltage clamp pulses was studied. The properties of currents remaining in cobalt-Ringer or after TEA injection were compared with those in untreated cells. 2. With sustained voltage clamp depolarizations the net outward current first increases to a maximum at 150 msec and then declines to 60% or less of its peak intensity. This depression, which is greater during repetition of short pulses (e.g. 100 msec pulses at 0-5 sec intervals), represents a true decrease in the outward flow of K (designated IK) and is not due to a decreased driving force resulting from extracellular K accumulation. The steady-state current-voltage (I-V) relationship for IK is N-shaped (Heyer & Lux, 1976). 3. A component of IK persists when Ca and Mg in the medium are replaced by Co (ICo-res). With voltage clamp depolarizations ICo-res increases rapidly to a maximum and then partially inactivates with voltage dependent time constants of hundredths or tenths of seconds. Repolarization removes the inactivation. Thus, repeated stimulation with short pulses does not increase the depression of ICo-res-ICo-res (e.g. measured during voltage steps from holding potentials of -50 to near 0 mV) is smaller in test pulses preceded by depolarization and larger in pulses preceded by hyperpolarization. The steady state I-V relationship is not N-shaped. ICo-res is blocked by intracellular injection of tetraethylammonium (TEA). 4. Repeated voltage clamp depolarization to near 0 mV with 100 msec pulses for neurones with large Ca currents in normal Ringer produces a long-term depression which is maximal with 300-400 msec repolarizations (to -50 mV) between pulses. This corresponds with stimulus parameters for the maximum Ca current (Heyer & Lux, 1976). Intracellular injection of Ca2+ (also Ba2+ and Co2+) likewise reduces the total net outward current and especially the delayed outward current under voltage clamp. 5. The component of IK which is removed by Co is identified as Ca dependent and designated IK(Ca). With single voltage clamp pulses IK(Ca) follows the approximate time course and voltage dependence of the slow inward Ca current (Iin slow; Heyer & Lux, 1976). Several lines of evidence suggest that Ca ions moving through the membrane activate IK(Ca). 6. Part of IK cannot be blocked by intracellular TEA injection. In different neurones the magnitude of the IK component resistant to TEA (ITEA-res) is approximately proportional to the relative magnitudes of Iin slow.ITEA-res does not inactivate with sustained depolarization and shows pronounced long-term depression with repetitive stimulation at intermediate intervals and an increased outward current at the onset of the second and subsequent pulses following short repolarizations. The steady-state I-V relationship is N-shaped. ITEA-res is abolished by extracellular Co. 7. A net inward current with low depolarizations can be measured after TEA injection...