Energy metabolism in sedentary and active 49- to 70-yr-old women

This study examined differences between long-term exercising (LE) and long-term nonexercising (LNE) women [n = 24; age 56.4 +/- 6.2 (SD) yr] for resting metabolic rate (RMR) and energy expenditure in the free-living state by using doubly labeled water (DLW). There was a statistically significant difference (P = 0.0002) between the 12 LE (94.85 +/- 8.44 kJ . kg-1 . day-1) and 12 LNE (81.16 +/- 6.62 kJ . kg-1 . day-1) for RMR, but this difference was only marginally significant (P = 0.06) when the data (MJ/day) were subjected to an analysis of covariance with fat-free mass as the covariate. The DLW data indicated that the eight most active LE (12.99 +/- 3.58 MJ/day) expended significantly (P = 0.01) more energy than did the eight least active LNE (9.30 +/- 1.15 MJ/day). Energy expenditures ranged from 7.64 to 18.15 MJ/day, but there was no difference (P = 0.96) between the LE and LNE in energy expenditure during activity that was not designed to either improve or maintain fitness. These cross-sectional data on 49- to 70-yr-old women therefore suggest that 1) aerobic-type training results in a greater RMR per unit of body mass and also when statistical control is exerted for the effect of the metabolically active fat-free mass, 2) there is a large range in the energy intake necessary to maintain energy balance, and 3) aerobic training does not result in a compensatory reduction in energy expenditure during the remainder of the day.     

Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migration

Human procathepsin L has been expressed in E. coli in the form of inclusion bodies. The recombinant protein was isolated, refolded and processed at pH 5.5 by the addition of dextran sulfate which increased the overall yield of cathepsin L almost 10-fold. After the auto-activation of the 38 kDa procathepsin L at least three processing sites were determined by N-terminal amino acid sequencing. After replacing the Ala205 residue by glutamic acid, cathepsin B-like specificity was introduced into cathepsin L. This mutation resulted in a 15-fold increased activity toward the substrate Z-Arg-Arg-AMC and in a 29-fold decreased activity toward Z-Phe-Arg-AMC. Residue 205 is thereby confirmed experimentally to be critical for the specificity of cathepsins B and L.     

Statistical modeling using preoperative prognostic variables in predicting extracapsular extension and progression after radical prostatectomy for prostate cancer

OBJECTIVE: To predict the risk of extracapsular extension and postoperative recurrence before radical prostatectomy (RP) for prostate cancer. METHODS: We performed multivariate Cox regression analysis on preoperative variables in 260 clinically localized prostate cancer patients who underwent RP. With these data, we constructed a relative risk of recurrence (Rr) equation and an equation to predict the probability of extracapsular extension (PECE) before RP. RESULTS: Rr is calculated as exp[(0.47 x race + 0.14 x PSAST) + (0.13 x worst biopsy Gleason sum) + (1.03 x stage T1c) + (1.55 x stage T2b,c)], where PSAST indicates a sigmoidal transformation of prostate-specific antigen. PECE is calculated as 1/[1 + exp(-Z)], where Z = -2.47 + 0.15 (PSAST) + 0.31 (worst biopsy Gleason sum) + 0.18 (race) + 0.16 (stage T1c) + 0.38 (stage T2b,c). CONCLUSION: These two equations can be used preoperatively to predict the probability of extracapsular disease and the risk of prostate-specific antigen recurrence in patients undergoing RP.     

Exploring structure-activity relationships around the phosphomannose isomerase inhibitor AF14049 via combinatorial synthesis

Phosphomannose Isomerase (PMI) has been shown by genetic methods to be an essential enzyme in fungal cell wall biosynthesis. The PMI inhibitor AF14049 was discovered as an unanticipated side product from high-throughput library screening against the enzyme from C, albicans. Solid-phase synthetic methods were developed and a series of libraries and discrete analogs synthesized to explore SAR around AF14049.     

Sustaining interventions in community systems: on the relationship between researchers and communities

Important goals of research-based community interventions include the long-term maintenance of effects and fostering of collaboration between researchers and community leaders. This article reviews the challenges associated with transferring innovations to community systems, changing program delivery from an experimental context controlled by researchers to program delivery controlled by community organizations, and sustaining long-term effects of interventions. It is suggested that researchers who develop and implement community interventions in diverse health areas need to confront several issues: (a) fostering effective long-term relationships between researchers and the communities they study and in which they intervene and (b) designing and implementing interventions that are useful to community systems after the formal phase of research ends.     

Use of a two-compartment model to assess the pharmacokinetics of human ethanol metabolism

The relationship between blood ethanol concentration and hepatic ethanol metabolism commonly is calculated using the Michaelis-Menten equation and a one-compartment model that assumes equality of blood and hepatic ethanol concentrations. However, at low blood concentrations, most of the ethanol arriving at the liver is metabolized, and hepatic ethanol concentrations may fall far below that of the entering blood. We have developed a two-compartment model of ethanol metabolism that accounts for the fall in ethanol concentration that may occur as blood traverses the liver and used this model to make predictions concerning ethanol metabolism at various blood ethanol concentrations. The two-compartment model predicts that near-complete saturation will occur more abruptly and at a lower blood concentration (approximately 3 mM) than is the case with the one-compartment model. Thus, the two-compartment model predicts a near-constant ethanol elimination rate for blood ethanol concentrations above 3 mM (as commonly observed in human subjects), whereas the one-compartment model predicts an increasing elimination rate over the range of concentrations observed in experimental studies. In agreement with observed data, the two-compartment model predicts that first-pass metabolism should be extremely sensitive to the rate of ethanol absorption. Application of this model to previously published data indicated that, when absorption was slowed via concomitant food ingestion, first-pass metabolism accounts for approximately 50% and 10% of ethanol dosages of 0.15 g/kg and 0.3 g/kg, respectively. When ingested without food, there is negligible first-pass metabolism of even very small ethanol dosages (0.15 g/kg). These findings suggest that first-pass metabolism is an unimportant determinant of the blood ethanol response to ingestion of potentially inebriating doses of ethanol.     

Independent origin of multiple foci of prostatic intraepithelial neoplasia: comparison with matched foci of prostate carcinoma

BACKGROUND: Prostate carcinoma usually is heterogeneous and multifocal, with diverse clinical and morphologic manifestations. Understanding of the molecular basis for this heterogeneity is limited, particularly for the putative precursor, high grade prostatic intraepithelial neoplasia (PIN). In this study, the authors attempted to determine the genetic relation between multiple foci of PIN and matched foci of carcinoma, and whether they are independent in origin. METHODS: The distribution and prevalence of allelic imbalance at 6 microsatellite polymorphic markers on chromosomes 7q, 8p, 8q, and 18q were examined in 84 microscopically excised PIN foci (mean, 1.6 foci/case) and 95 foci of prostate carcinoma (mean, 1.8 foci/case) from 52 completely embedded, mapped whole mount prostates. RESULTS: PIN contained a lower overall proportion of allelic imbalance than matched prostate carcinoma foci for the 6 polymorphic microsatellite markers (65% vs. 82%), but this difference was not significant. The rate of allelic imbalance in PIN was similar to that in prostate carcinoma at 5 of 6 loci studied; the exception, D18S34 (18q12.2-12.3), had a significantly lower rate of allelic imbalance in PIN than in prostate carcinoma (19% vs. 52%), suggesting that genetic alterations in this chromosomal region may be important in carcinogenesis. Of 22 cases with allelic imbalance in at least 1 focus of PIN and 1 focus of prostate carcinoma, 21 informative cases (95%) showed a similar pattern of allelic imbalance at > or = 1 markers in the matched PIN and prostate carcinoma foci. Significant genetic heterogeneity was observed in both PIN and prostate carcinoma. Allelic imbalance was observed in at least 1 focus in 11 of 25 cases with multiple foci of PIN (44%) and 20 of 25 cases with multiple foci of prostate carcinoma (80%). There was no significant correlation between allelic imbalance and pathologic stage or tumor grade. CONCLUSIONS: Our findings indicate that multiple foci of PIN arise independently within the same prostate. This observation suggests that a field effect underlies prostatic neoplasia. Multiple foci of prostate carcinoma also often arise independently, lending additional support for this hypothesis. The strong genetic similarities between PIN and prostate carcinoma strongly suggest that evolution and clonal expansion of PIN may account for the multifocal etiology of carcinomas.     

The effect of follicle stimulating hormone and epidermal growth factor on the developmental capacity of in-vitro matured mouse oocytes

Staphylococcus aureus produces and secretes a protein, Efb, that binds to fibrinogen, seems to be required for virulence, and may benefit the microorganism by delaying wound healing. Interactions of Efb with fibrinogen are influenced by divalent metal cations, including Ca2+. Increasing concentrations of Ca2+ increased the binding of fibrinogen to immobilized Efb, whereas binding of Efb to immobilized fibrinogen was decreased with increasing Ca2+ concentration. Studies with synthetic peptides showed that peptides from the carboxyl terminal half of Efb bound to soluble fibrinogen and enhanced the binding of fibrinogen to Efb. A peptide corresponding to a repeated sequence in the amino terminal half of the protein also bound fibrinogen and inhibited binding of fibrinogen to Efb. These results may provide clues to the biological function of Efb and aid in the rational design of agents to block the Efb fibrinogen interaction.     

Visual marking of moving objects: a role for top-down feature-based inhibition in selection

Recently, the authors presented evidence that new items can be prioritized for selection by the top-down attentional inhibition of old stimuli already in the field (visual marking; D. G. Watson & G. W. Humphreys, 1997). In this article the authors assess whether this inhibition extends to moving old items and test an alternative account of visual marking. Six experiments showed that old moving items could be inhibited provided they did not undergo abrupt property changes. Further, and in contrast to effects with static stimuli, the marking of old moving stimuli was based on inhibition applied at the level of a whole feature map, rather than at their locations. The results also rule out an alternative account of visual marking based on the top-down weighting of dynamic or static processing pathways.