Modest release of adipsin/factor D by liposuction when using the superwet or tumescent technique

Human adipsin is recognized to be identical to factor D, which plays an important role in activation of the alternative complement pathway. Since adipsin/factor D is present in high amounts in adipose tissue, liposuction theoretically could result in an increased release of this serine protease into the bloodstream. In the present study, adipsin/factor D was measured in 22 patients undergoing syringe-assisted liposuction using the superwet or tumescent technique. Despite a relatively high mean aspirate volume (2648 ml), only a very modest increase in adipsin/factor D concentration was found during liposuction. All values before, during, and after liposuction were within the range found in healthy blood donors. Furthermore, there was no correlation between adipsin/factor D values and C3 activation products. We conclude that liposuction with the present techniques results in a very modest release of adipsin/factor D that is not associated with increased complement activation.     

Specific identification of Mycobacterium tuberculosis with the luciferase reporter mycobacteriophage: use of p-nitro-alpha-acetylamino-beta-hydroxy propiophenone

We have previously described a luciferase reporter mycobacteriophage (LRP) assay that can detect Mycobacterium tuberculosis and characterize mycobacterial drug susceptibility patterns within 24 to 48 h in positive cultures. One drawback of this LRP protocol is the ability of the recombinant mycobacteriophage phAE40 to infect a variety of Mycobacterium species, thus limiting its specificity for the detection of M. tuberculosis. In this study, we have (i) explored the host range of phAE40, (ii) developed a modified LRP assay that exploits the selective inhibitory effect of the compound p-nitro-alpha-acetylamino-beta-hydroxy propiophenone (NAP) against members of the M. tuberculosis complex to differentiate between the tubercle bacillus and other mycobacterial species, and (iii) tested over 300 samples, including primary clinical isolates and drug-resistant strains of M. tuberculosis, demonstrating the ability of the NAP-modified LRP assay to identify M. tuberculosis complex organisms with high degrees of sensitivity and specificity.     

Both conserved region 1 (CR1) and CR2 of the human papillomavirus type 16 E7 oncogene are required for induction of epidermal hyperplasia and tumor formation in transgenic mice

High-risk human papillomavirus type 16 (HPV-16) and HPV-18 are associated with the majority of human cervical carcinomas, and two viral genes, HPV E6 and E7, are commonly found to be expressed in these cancers. The presence of HPV-16 E7 is sufficient to induce epidermal hyperplasia and epithelial tumors in transgenic mice. In this study, we have performed experiments in transgenic mice to determine which domains of E7 contribute to these in vivo properties. The human keratin 14 promoter was used to direct expression of mutant E7 genes to stratified squamous epithelia in mice. The E7 mutants chosen had either an in-frame deletion in the conserved region 2 (CR2) domain, which is required for binding of the retinoblastoma tumor suppressor protein (pRb) and pRb-like proteins, or an in-frame deletion in the E7 CR1 domain. The CR1 domain contributes to cellular transformation at a level other than pRb binding. Four lines of animals transgenic for an HPV-16 E7 harboring a CR1 deletion and five lines harboring a CR2 deletion were generated and were observed for overt and histological phenotypes. A detailed time course analysis was performed to monitor acute effects of wild-type versus mutant E7 on the epidermis, a site of high-level expression. In the transgenic mice with the wild-type E7 gene, age-dependent expression of HPV-16 E7 correlated with the severity of epidermal hyperplasia. Similar age-dependent patterns of expression of the mutant E7 genes failed to result in any phenotypes. In addition, the transgenic mice with a mutant E7 gene did not develop tumors. These experiments indicate that binding and inactivation of pRb and pRb-like proteins through the CR2 domain of E7 are necessary for induction of epidermal hyperplasia and carcinogenesis in mouse skin and also suggest a role for the CR1 domain in the induction of these phenotypes through as-yet-uncharacterized mechanisms.     

Evaluation of the frictional properties of an elastomer with enhanced lipid-adsorbing ability

Wear particle production in load-bearing orthopaedic implants is one of the major factors currently limiting the service life of the implant. Most of the research carried out to date in attempting to solve this problem has used the approach of finding more wear-resistant biocompatible material pairs. In contrast, other researchers have attempted to reduce wear by encouraging elastohydrodynamic film formation through the use of elastomeric bearing surfaces. Unfortunately, these elastomeric bearing surfaces have poor tribological properties when a fluid film is not present. Boundary lubrication of an elastomeric orthopaedic bearing may alleviate some of these difficulties. The purpose of this research was to fabricate and characterize an elastomeric material that had a surface capable of specifically adsorbing a naturally occurring boundary lubricant. Dipalmitoyl phosphatidylcholine (DPPC) has been previously shown to be able to act as a boundary lubricant at stresses that occur in human load-bearing joints such as the hip and knee; therefore, DPPC was chosen for use in this study. It was expected that in an aqueous liposome suspension the static coefficient of friction microseconds of such a material would be lower, and increase less quickly over time, than a similar material without an ability to adsorb specifically DPPC when articulated against a polished chrome steel ball bearing. The lipid-adsorbing elastomer did not possess the desired tribological properties. This result was attributed to the polymer adsorbing the DPPC in the liposome phase and not in the bilayer phase, and interaction among the polymeric surface, DPPC and water. This approach to lubricating orthopaedic bearings was shown to have some merit, but a great deal of work needs to be done before such an approach can be used on a clinically available material.     

Serum levels of endothelial and neural cell adhesion molecules in prostate cancer

The purpose of this study was to describe the longitudinal development of running economy [defined as the oxygen uptake (VO2) at a submaximal running speed] in males and females from teenage to young adult age using data from the Amsterdam Growth and Health Study. Submaximal VO2 (in ml.kg-1.min-1) was measured in 84 males and 98 females while they ran on a treadmill at a constant speed of 8 km.h-1 for 6 min at three different treadmill slopes (0%, 2.5% and 5%). This test was carried out six times, on the same subjects at the ages of 13, 14, 15, 16, 21, and 27 years. The longitudinal development of running economy in males and females was analysed using a two-way analysis of variance for repeated measurements. At all three slopes, a significant decrease in VO2 with increasing age was found for both males and females, implying a significant increase in running economy for both sexes. Males showed significantly higher VO2 values than females at all ages measured and for all three slopes, suggesting that females have a significantly higher running economy than males. In order to make a better comparison of the VO2 of individuals of different sizes, allometric models were used; power function ratios were constructed in which body mass was expressed to an exponential power. Following this analysis the difference in submaximal VO2 and running economy between males and females appeared even larger.     

A single-residue deletion alters the lipid selectivity of a K+ channel-associated peptide in the beta-conformation: spin label electron spin resonance studies

Lipid-peptide interactions with the 27-residue peptide of sequence KLEALYILMVLGFFGFFTLGIMLSYIR reconstituted as beta-sheet assemblies in dimyristoylphosphatidylcholine bilayers have been studied by electron spin resonance (ESR) spectroscopy with spin-labeled lipids. The peptide corresponds to residues 42-68 of the IsK voltage-gated K+ channel protein and contains the single putative transmembrane span of this protein. Lipid-peptide interactions give rise to a second component in the ESR spectra of lipids spin-labeled on the 14C atom of the chain that corresponds to restriction of the lipid mobility by direct interaction with the peptide assemblies. From the dependence on the lipid/peptide ratio, the stoichiometry of lipid interaction is found to be about two phospholipids/peptide monomer. The sequence of selectivity for lipid association with the peptide assemblies is in the order phosphatidic acid > stearic acid = phosphatidylserine > phosphatidylglycerol = phosphatidylcholine. Comparison with previous data for a corresponding 26-residue mutant peptide with a single deletion of the apolar residue Leu2 (Horvath et al., 1995. Biochemistry 34:3893-3898), indicates a very similar mode of membrane incorporation for native and mutant peptides, but a strongly modified pattern and degree of specificity for the interaction with negatively charged lipids. The latter is interpreted in terms of the relative orientations of the charged amino acid side chains in the beta-sheet assemblies of the native and deletion-mutant peptides.     

Long-term metabolic advantages of a gastrointestinal composite urinary reservoir

PURPOSE: We investigated the long-term metabolic impact of gastrointestinal composite reservoirs. MATERIALS AND METHODS: Nine patients underwent construction of a gastroileal (7) or gastrocolonic (2) reservoir for continent urinary diversion. Four cases of metabolic acidosis were converted from a preexisting conduit and the other 5 patients had diversion for either preexisting metabolic acidosis or the short bowel syndrome. All were reconstructed using a medium sized gastric segment (8 x 4 cm.) from the greater curvature of the stomach. The anti-incontinence segment was constructed from a tapered and reimplanted ileal segment. All patients underwent preoperative and postoperative measurements of serum pH, serum electrolytes, and urinalysis. Serum gastrin was measured in all patients postoperatively. Followup from surgery ranged from 47 to 61 months (mean 54.4). RESULTS: All 9 patients demonstrated electrolyte neutrality in serum on long-term followup. Postoperative serum pH (mean 7.40) was significantly different (p < 0.01) from preoperative serum pH (mean 7.36) and serum bicarbonate was also significantly different (p < 0.01) preoperatively versus postoperatively (mean 22.3 versus 25.14). Urine pH values were not significantly different throughout the study. One patient with mildly acidic urinary pH (6.0 to 6.5) had ulcerative skin changes at the stoma site. Three patients had elevated serum gastrin levels on short-term followup but all patients had normal serum gastrin levels on long-term followup. One patient, with persistent alkaline urine, had urolithiasis and symptomatic urinary tract infections. CONCLUSIONS: Our results demonstrate that a composite urinary reservoir constructed using gastric and intestinal segments achieved serum electrolyte neutrality on long-term followup. These results indicate a long-term metabolic advantage over other intestinal reservoirs associated with hyperchloremic metabolic acidosis and may be beneficial in patients compromised by either preexisting metabolic acidosis or the short bowel syndrome.