Prolonged bed rest impairs response of the small arteries to cold pressor test

Cold pressor test (CPT) has been known to increase vascular resistance through adrenergic stimulation. To assess the effect of prolonged bed rest (BR) on sympathetic neural control, blood flow velocity of the proper palmar digital artery (resistance vessel) was measured in 10 healthy volunteers during a 90 seconds CPT by pulsed Doppler ultrasound using a 7.5 MHz linear transducer before and after 20 days BR. Blood flow velocity in the proper palmar digital artery decreased during the first half of the CPT both before and after BR, but decreases in peak flow velocity became less prominent (p<0.05) after BR (-48+/-20%) than before bed rest (-61+/-25%). The only subject whose lower body negative pressure tolerance time was prolonged after BR showed prominent decreases in peak flow velocity during the first half of the CPT after BR. Peak flow velocity returned to the pre-test value during the latter half of the CPT in 7 subjects before BR, but in only 2 subjects after BR (p<0.05). Thus, 20 days BR impairs the response of the small digital arteries to CPT, suggesting that a decrease in a adrenergic stimulation occurs after prolonged BR.     

Changes in force-velocity and power output of upper and lower extremity musculature in young subjects following 20 days bed rest

Ten healthy sedentary students were exposed to 20 days bed rest (BR) to study the effect of simulated weightlessness on force(F)-velocity(V) characteristics and power(P) output of upper and lower limb movements. F, V and P were measured using a special dynamometer applicable to single joint movements [elbow flexion(EF) and extension(EE), knee flexion(KF) and extension(KE), and hip flexion] or multi-joint movements (squatting). Physiological cross-sectional areas(PCSA) of KF and KE muscles were measured by a magnetic resonance imaging technique. After BR, attenuation in P were observed in lower limb movements (decreased by 19.8-43.6% for squatting, KF and KE), in upper limb movements on the other hand, the decreases in P were not significant (approximately -5% for EF and EE). Decrease in P in lower limb were more pronounced in heavier loaded conditions which were characterized by decreases in both F and V. For KF and KE, decreases in maximal static F (-18.9 to approximately -26.8%) were more pronounced than the decreases observed in the PCSA (approximately -7%), resulting in decreases in specific tension (-12.3 to approximately -22.1%). Neural excitation potentials to generate maximal muscle tension or P might also be influenced by weightlessness.     

Dual interaction producing both territorial and schooling behavior in fish

Fish schools are frequently observed without a leader and an explicit condition forming school. Several models of schooling have been proposed focusing on the influence of neighbors, and introducing probability distributions, while these models are based on the separation of schooling and territorial behavior. We frequently consider the duality of aggregation of animals, in which behavioral patterns involve both attraction and repulsion, antagonistic with each other. The idea of probability does not explain this duality that can provide both schooling and territorial behavior. From these biological facts, we have constructed a behavior model in which the influence of neighbors is formulated by the interface between the states of neighbors and a map of changes in these states. This interface uses a self-similar nowhere differentiable transition map which is temporally constructed, encompassing a crucial duality of repulsive and attractive forces hidden in the interaction among fishes. We tested it with computer simulations against the biological reality of schooling and territorial behavior. Due to the influence neighbors can have on duality, the same model can show both schooling behavior with a high degree of polarization and territorial behavior.     

Breast form changes resulting from a certain brassière

Eleven adult female subjects aged 22-39 years wore a certain brassière for 3 months while anthropometry and moiré fringe photographs on the anterior trunk were taken regularly once a week. After the 3 months, the brassière was not worn for another 3 months. Then the measurements and photogrammetry were repeated for comparison using superimposed moiré configurations. The results are summarized as follows. Regardless of slim or obese trunk, subjects with pendent breasts showed the highest degree of breast form "correction" from wearing the brassière. In all subjects, after 3 months of brassière constraint, the underbust circumference was smaller but the chest circumference became enlarged, the distance between the right and left nipples became wider, and the breasts tended to hang down. This change was more marked in obese subjects with pendent breasts. And when this type of subject wore a "well-fitted" brassière for a long time, her breast form became developed; that is, her breasts hung down more.     

Discovery of selective and nonpeptidic cathepsin S inhibitors

Nonpeptidic, selective, and potent cathepsin S inhibitors were derived from an in-house pyrrolopyrimidine cathepsin K inhibitor by modification of the P2 and P3 moieties. The pyrrolopyrimidine-based inhibitors show nanomolar inhibition of cathepsin S with over 100-fold selectivity against other cysteine proteases, including cathepsin K and L. Some of the inhibitors showed cellular activities in mouse splenocytes as well as oral bioavailabilities in rats.     

FISH-mapping of 18S ribosomal RNA genes and telomeric sequences in the Japanese bitterlings Rhodeus ocellatus kurumeus and Tanakia limbata (Pisces,Cyprinidae) reveals significant cytogenetic differences in morphologically similar karyotypes

The Japanese rose bitterling, Rhodeus ocellatus kurumeus, and the oily bitterling, Tanakia limbata, were cytogenetically studied by silver (Ag)- and chromomycin A₃ (CMA₃)-staining, by C-banding and by mapping of the 18S ribosomal genes and of the (TTAGGG) _n telomeric sequence. These two representative species of related genera of the subfamily Acheilognathinae show very similar chromosome complements. Nevertheless, significant differences in the chromosomal distribution of nucleolus organizer regions (NORs) and interstitial telomeric sequences were observed. Whereas R. ocellatus kurumeus shows a single NOR-bearing chromosome pair, T. limbata is characterized by a higher number of variable NORs. Multiple telomeric sequence sites were found at the pericentromeric regions of several chromosomes in the rose bitterling. No telomeric sequence sites were detected near centromeres, but they were found to be scattered along the NORs in the oily bitterling. Two karyoevolutive trends might have been identified in the subfamily.     

Administration of parathyroid hormone, prostaglandin E2, or 1-alpha,25-dihydroxyvitamin D3 restores the bone inductive activity of rhBMP-2 in aged rats

Bone morphogenetic protein (BMP) induces bone formation in young rodents, but aging causes a reduction in the bone-forming ability of BMP. Most patients who require bone reconstruction are relatively old. Accordingly, we examined whether anabolic hormones could restore the bone inductive activity of rhBMP-2 in aged rats. rhBMP-2 in a carrier pellet was implanted subcutaneously in both 4- and 50-week-old female Wistar rats. PTH, PGE2, or 1,25(OH)2D3 was injected every day during the period of BMP implantation. The pellets were harvested, and were examined both histologically and biochemically 2 weeks after implantation. Bone-forming ability was measured by alkaline phosphatase (ALP) activity and calcium (Ca) content. Pellets in 50-week-old rats showed a significant reduction in bone formation compared to pellets in 4-week-old rats. However, daily injections of PTH into 50-week-old rats restored both ALP activity (103 +/- 4.6%) and Ca content (105 +/- 2.6%). 1,25(OH)2D3 and PGE2 also restored Ca content (103 +/- 4.5% and 98 +/- 3.8%, respectively) and stimulated ALP activity (142 +/- 2.3% and 133 +/- 3.6%). These results show that the administration of these hormones restores bone-forming ability in aged rats. A combination treatment of these hormones with rhBMP-2 might be applicable to the reconstruction of bone defects in elderly patients.     

Interleukin-6 deficiency increases blood volume without altering body composition in young mice

This study was carried out to measure blood volume in interleukin-6 (IL-6) deficient and the wild type mice and to relate any differences to concomitant changes in body composition. Young animals (8-20 weeks of age) were used in this study. The red blood cell (RBC) and plasma volumes were measured by isotope-dilution using Cr(51)-labeled erythrocytes and I(131)-labeled human albumin injected simultaneously in each animal. Red blood cells and plasma volumes and hence total measured blood volume were significantly larger in the IL-6-deficient than in either male or female wild type mice. There were no differences in either whole body hematocrit or Fcells ratio. There were no differences in water, fat, protein and mineral content between the genotypes of either gender. Thus, IL-6-deficient mice at young age have a significantly greater blood volume than the wild type mice without concomitant changes in body composition. We suggest that the changes in blood volume may reflect a role for IL-6 in the regulation of the peripheral circulation.