Evaluation of low-intensity physical activity by triaxial accelerometry

Objective: To develop regression‐based equations that estimate physical activity ratios [energy expenditure (EE) per minute/sleeping metabolic rate] for low‐to‐moderate intensity activities using total acceleration obtained by triaxial accelerometry. Research Methods and Procedures: Twenty‐one Japanese adults were fitted with a triaxial accelerometer while also in a whole‐body human calorimeter for 22.5 hours. The protocol time was composed of sleep (8 hours), four structured activity periods totaling 4 hours (sitting, standing, housework, and walking on a treadmill at speeds of 71 and 95 m/min, 2 × 30 minutes for each activity), and residual time (10.5 hours). Acceleration data (milligausse) from the different periods and their relationship to physical activity ratio obtained from the human calorimeter allowed for the development of EE equations for each activity. The EE equations were validated on the residual times, and the percentage difference for the prediction errors was calculated as (predicted value ? measured value)/measured value × 100. Results: Using data from triaxial accelerations and the ratio of horizontal to vertical accelerations, there was relatively high accuracy in identifying the four different periods of activity. The predicted EE (882 ± 150 kcal/10.5 hours) was strongly correlated with the actual EE measured by human calorimetry (846 ± 146 kcal/10.5 hours, r = 0.94 p < 0.01), although the predicted EE was slightly higher than the measured EE. Discussion: Triaxial accelerometry, when total, vertical, and horizontal accelerations are utilized, can effectively evaluate different types of activities and estimate EE for low‐intensity physical activities associated with modern lifestyles.     

Triaxial accelerometry for assessment of physical activity in young children

Objective: The purpose of the present study was to derive linear and non‐linear regression equations that estimate energy expenditure (EE) from triaxial accelerometer counts that can be used to quantitate activity in young children. We are unaware of any data regarding the validity of triaxial accelerometry for assessment of physical activity intensity in this age group. Research Methods and Procedures: EE for 27 girls and boys (6.0 ± 0.3 years) was assessed for nine activities (lying down, watching a video while sitting and standing, line drawing for coloring‐in, playing blocks, walking, stair climbing, ball toss, and running) using indirect calorimetry and was then estimated using a triaxial accelerometer (ActivTracer, GMS). Results: Significant correlations were observed between synthetic (synthesized tri‐axes as the vector), vertical, and horizontal accelerometer counts and EE for all activities (0.878 to 0.932 for EE). However, linear and non‐linear regression equations underestimated EE by >30% for stair climbing (up and down) and performing a ball toss. Therefore, linear and non‐linear regression equations were calculated for all activities except these two activities, and then evaluated for all activities. Linear and non‐linear regression equations using combined vertical and horizontal acceleration counts, synthetic counts, and horizontal counts demonstrated a better relationship between accelerometer counts and EE than did regression equations using vertical acceleration counts. Adjustment of the predicted value by the regression equations using the vertical/horizontal counts ratio improved the overestimation of EE for performing a ball toss. Discussion: The results suggest that triaxial accelerometry is a good tool for assessing daily EE in young children.     

Conversion of Hypoxanthine Derivatives to Succinyl Adenine Derivatives by Bacillus subtilis

A mutant strain HA-2 was derived from an adenine-requiring mutant of Bacillus subtilis IAM 1145 by transduction with bacteriophage SP-10 and subsequent N-methyl-N′-nitro-N-nitrosoguanidine treatment. The strain could convert exogenously supplemented hypoxanthine or inosine to succinyladenine, succinyladenosine and succinyladenosine 5′-monophosphate (succinyl AMP), and accumulate these compounds in the culture fluid. The strain, however, failed to convert exogenously supplemented inosine 5′-monophosphate to these succinyl compounds. The yields of succinyladenine, succinyladenosine and succinyl-AMP in a production medium supplemented with 17 mm of hypoxanthine were about 4.4 mm, 5.2 mm and 2.2 mm, respectively, after 4 days growth.     

The neutrophil as an information transmitter in tumor inhibition by a streptococcal biological response modifier,OK-432

 Effective treatment of a rat transplanted ascites tumor by i. p. injection of a streptococcal biological response modifier, OK-432, was abrogated by selective in vivo depletion of neutrophils by a monoclonal antibody, RP-3. The mechanisms by which neutrophils participate in the therapeutic action of OK-432 were studied with Winn’s assay using peritoneal exudate cells periodically obtained from rats i. p. injected with this biological response modifier. Intraperitoneal resident macrophages were first activated with OK-432, and within 3 h, tumor-inhibitory activity had moved to the early exuded neutrophils. However, 6 h after injection, exuded macrophages were the only cells involved in tumor inhibition. Considered together with other findings, it is likely that, in this system, neutrophils may transmit information from resident macrophages to exuded inflammatory macrophages in a series of responses induced by i. p. injection of OK-432. Received: 29 April 1996 / Accepted: 27 July 1996     

Hepatoprotective and anti-Helicobacter pylori activities of constituents from Brazilian propolis.

Propolis is a resinous hive product collected by honeybees from various plant sources. It is extensively used in food, beverage and in folk medicine for treating various ailments and reported to have broad spectrum of biological activities. The hepatoprotective activity of propolis and constituents from its MeOH extract belonging to various classes were tested on D-galactosamine (D-GalN)/tumor necrosis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes. The result indicated that hepatoprotective activity of alcoholic extract of tropical Brazilian propolis is mainly due to phenolic compounds including flavonoids. All the four isolated flavonoids possessed stronger inhibitory activity (IC50, < 25 microM) than silibinin (IC50, 39.6 microM) on TNF-alpha-induced cell death. The labdane-type diterpenes isolated from the MeOH extract also exhibited significant hepatoprotective activity in the same experimental model. Moreover, the labdane-type diterpenes and some of the prenylated phenolic compounds possessed antibacterial activity against Helicobacter pylori.     

Nephrotoxicity and its prevention by vitamin E in ferric nitrilotriacetate-promoted lipid peroxidation

Iron and aluminum complexes of nitrilotriacetic acid cause severe nephrotoxicity in Wistar rats. In addition, a high incidence of renal cell carcinoma is seen in ferric nitrilotriacetate-treated animals. The present study was performed to see if lipid peroxidation is involved in ferric nitrilotriacetate toxicity. Ferric nitrilotriacetate had more bleomycin-detectable 'free' iron than any ferric salt, while iron complexed with desferrioxamine or ferric chondroitin sulfate had none. The toxicity of ferric nitrilotriacetate in vivo was more pronounced in vitamin E-deficient rats. A thiobarbituric acid-reactive substance was present in the kidneys of vitamin E-deficient rats in amounts markedly elevated compared to vitamin E-sufficient, or vitamin E-supplemented rats. Non-complexed nitrilotriacetate or aluminum nitrilotriacetate did not produce any thiobarbituric acid-reactive substance in vitamin E-sufficient rats died by the 58th day of administration. We suggest that the iron-stimulated production of free radicals leading to lipid peroxidation is the major cause of ferric nitrilotriacetate-mediated renal toxicity. Vitamin E, a known scavenger of free radicals, is effective in protecting against this iron-induced toxicity.     

Growth inhibition of Candida by 15-deoxyspergualin, an immunosuppressive agent used in experimental organ transplantation

The metabolic and antiproliferative effects of 15-deoxyspergualin (DSG), an immunosuppressive agent used in experimental organ transplantation, on Candida albicans were investigated. The minimal inhibitory concentration of DSG for C. albicans was 31·3 μ g/ml and it depleted intracellular putrescine, spermidine and spermine to 57, 55 and 71% of control levels, respectively. In such polyamine-depleted cells, the synthesis of DNA. RNA and protein were decreased to 56, 71 and 79% of the control. This suggests that the depression of intracellular polyamines by this drug may be a cause of the suppression of macromolecule biosyntheses and of growth of C. albicans.     

Der Einfluss der Fixation bei histochemischen Untersuchungen an enterochromaffinen Zellen und Panethschen Körnerzellen

Zusammenfassung Sowohl für die Darstellung der enterochromaffinen Zellen als auch des Zinks in der Darmschleimhaut mit dem Silbersulfidverfahren spielen Fixierungswirkungen eine entscheidende Rolle.Am Meerschweinchendarm wurden die Wirkungen der verschiedenen Fixierungsverfahren auf den Ausfall der einzelnen Methoden systematisch geprüft. Während durch die Fixierungszusätze die argentaffine und die Diazoniumreaktion relativ gleichartig beeinflußt werden, zeigen sowohl die Reaktion nachSchmorl als auch die argyrophile Reaktion nachBodian Unterschiede in Abhängigkeit von der verwandten Fixationsart. Auch das Silbersulfidverfahren wird hierbei zum Teil in Form zusätzlicher positiver Reaktionen beeinflußt.Bei kombinierten Untersuchungen der enterochromaffinen Zellen und des Zinks mit dem Silbersulfidverfahren müssen positive Befunde durch die Anwendung zusätzlicher spezifischer Reaktionen gesichert werden.Mit 1 TextabbildungHerrn Professor Dr.W. Hueck zum 80. Geburtstag.Stipendiat der Alexander-von-Humboldt-Stiftung.     

Possible involvement of p21 but not of p16 or p53 in keratinocyte senescence

It has been reported that p21, p53, and p16 affect the cell cycle and cell senescence. However, their roles in keratinocyte senescence are not clear. We established primary keratinocyte strains from 15 donors and maintained them until replicative senescence; their population doublings ranged from 5.7-45.2. These strains were classified based on their population doublings as short (5.7-10.4), intermediate (13.9-17.4), and long (21.5-45.2). To investigate the roles of p21, p53, and p16 in the cellular senescence of the cultured keratinocytes, we quantitatively analyzed p21, p53, and p16 levels of keratinocyte strains with different life spans by Western blot with Fluorol mager. p21 levels increased in the senescent phase but not in the nonsenescent phase in all of the short, intermediate, and long life-span strains. Northern blot analysis also revealed induction of p21 mRNA was similar to that of p21 protein levels. There were no apparent differences in p53 levels between senescent and nonsenescent cells. The short life-span strains exhibited a significant increase in p16 levels in the senescent phase (eighth or tenth passage). However, in two long life-span strains, p16 levels were increased in the nonsenescent phase (eighth passage) but then declined as the cells reached senescence (twenty-seventh passage). Therefore, induction of p16 appeared not to be associated with senescence in long life-span strains. In conclusion, p21 but not p16 or p53 may play roles in keratinocyte senescence.