Electrical stimulation of the suprachiasmatic nucleus of the hypothalamus causes hyperglycemia

We have presented evidence suggesting that the suprachiasmatic nucleus (SCN) is involved in central regulation of glucose homeostasis. To elucidate this role of the SCN, we examined the effects of its electrical stimulation on glucose metabolism in male Wistar rats. During and shortly after this stimulation, we observed hyperglycemia associated with enhanced hyperglucagonemia but no immediate hyperinsulinemia. In addition, we detected significant increase in liver glycogen phosphorylase alpha activity and significant decrease in the liver glycogen content. These findings suggest that the SCN is important in control of glucose homeostasis through effects on glucagon and insulin secretions and liver glycogen metabolism.     

A sensitive method for quantitative analysis of phospholipid molecular species by high-performance liquid chromatography

A simple and sensitive method was developed for quantitative analysis of phospholipid molecular species. Diacylglycerols were prepared from phospholipids by phospholipase C treatment and converted to the corresponding dinitrobenzoyl derivatives, which could be sensitively detected at 254 nm. The derivatives of 21 molecular species were resolved by high-performance liquid chromatography with an octadecylsilyl reversed-phase column. All the derivatives had the same peak area per mol, and peak areas were proportional to the amounts of the derivatives. Quantification was carried out at the picomole level.     

Effects of Cu,Cd and Zn on photosynthesis of freshwater benthic algae

One hundred and eighteen algal isolates comprising seven classes were obtained from a range of sites from polluted rivers running through Cu or Zn mining regions, and from unpolluted rivers. All the isolates were tested for photosynthetic activity when exposed to Cu, Cd or Zn. The tolerance levels of Bacillariophyceae, Charophyceae, Cyanophyceae and Chlorophyceae to Cu showed significant positive correlations with Cu concentrations in the field. However the distribution of metal sensitivities of the algae from the sites with the same metal concentration was broad. Both Bacillariophyceae and Charophyceae had a number of strains whose sensitivity to Cu differed more widely in relation to Cu levels in the environment than Cyanophyceae and Chlorophyceae. Cyanophyceae were sensitive to all three metals, whether or not isolates were obtained from polluted sites, whereas Chlorophyceae tended to have high tolerance even in isolates from unpolluted sites. For Cd and Zn the correlation between tolerance levels and concentrations in the field was not so clear as for Cu. The occurrence of Cu tolerance was shown in 4 diatom species and one Charophyceae, whereas metal resistance occurred in some Chlorophyceae. Cu-tolerant isolates tended also to be Zn-tolerant in Bacillariophyceae, and Cd-resistant isolates tended also to be Zn-resistant in Chlorophyceae.     

Potential Distribution and Ionic Concentration at the Bean Root Surface of the Growing Tip and Lateral Root Emerging Points

The electrical potential distribution has been measured preciselyaround the root surface of the bean sprout Vigna mungo (L) Hepper.A large negative potential well was found at the growth portionof the root tip. Also, in the matured region of the root, wefound a negative potential well at an unspecified position inspite of the fact that nothing was detected on the smooth surface.A lateral root emerge was found to have initiated after 15–20hours just at the position corresponding to the potential well.With the expectation that these potentials can be elucidatedbased on the transport of ions which are released or absorbedby the root as a result of cell activity, we precisely measuredthe concentrations of major ion species (K⁺, H⁺, and Cl^–)around the root. The theoretical potential distribution curvesobtained by putting all the concentration data into the Henderson'sEquation for a liquid junction (diffusion) potential coincidedwell with the experimental curves. (Received October 24, 1994; Accepted March 24, 1995)     

Differential pulse polarographic determination of plasma menadione

A differential pulse polarographic assay for plasma vitamin K₃ (menadione) has been developed. Details of the assay are (i) lipid-soluble material is extracted from plasma into ether by the method of Bjornsson et al. [(1978) Thromb. Haemostas.2, 466–473]; (ii) ether is evaporated under nitrogen and the residue is dissolved in the supporting electrolyte, methanol: 0.2 m borate buffer (9:1), pH 6.8; (iii) current height is measured at ?0.32 V vs SCE on the differential pulse polarogram. The lower sensitivity limit of this technique after addition of standard vitamin K₃ to plasma is 0.3 μm; the calibration curve is linear from 0.6 through 10 μm. Two patients treated with a single dose of menadiol sodium diphosphate, 20 mg/M² i.m., achieved measurable plasma vitamin K₃ levels at 0.5 to 1.0 h ranging between 0.5 (0.08 μg/ml) and 2 μm (0.3 μg/ml).     

Sexual difference and organ specificity of the effect of estradiol on carbonic anhydrase and Mg(2+)-HCO3(-)-ATPase activities isolated from duodenal mucosa and kidney cortex of male and female rats: preliminary study with crude enzyme samples.

Effects of the s.c. administration of various doses of estradiol propionate (E.P.; 25-500 micrograms/kg) on the activities of carbonic anhydrase (CA), Mg(2+)-dependent ATPase and Mg(2+)-dependent, HCO3(-)-stimulated ATPase (Mg(2+)-HCO3(-)-ATPase) in rat duodenal mucosa and kidney cortex, and on body weight, organ weight and serum concentrations of testosterone and estradiol-17 beta, were examined in adult male, female, testectomized and ovariectomized rats. In normal male rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the kidney were increased in a dose-dependent manner and reached 1.6- and 2-fold of controls, respectively, after consecutive administration (daily for 7 days) of 500 micrograms E.P. with no changes in either enzyme activities in duodenal mucosa. The positive correlations (P less than 0.01) were observed by linear regression analysis between serum concentration of estradiol-17 beta and kidney cytosol CA or kidney brush border Mg(2+)-HCO3(-)-ATPase activities. In normal female rats, activities of cytosol CA and brush border Mg(2+)-HCO3(-)-ATPase in the duodenal mucosa, and brush border Mg(2+)-HCO3(-)-ATPase activity in the kidney were increased by E.P. administration (100 and 500 micrograms/kg, daily for 7 days), however, kidney cytosol CA activity did not change by any dosage. Behavior of a part of both enzymes to E.P. in testectomized rats was altered almost in the same way to that observed in normal female rats and vice versa in ovariectomized rats. Body weight was decreased, in general, by consecutive administration of E.P. in a dose-dependent manner, and kidney weight was increased by E.P. in both male and female rats.     

Polarographic studies of the oxidation of vitamin K5 in aqueous solution.

Electrochemical behavior of 4-amino-2-methyl-1-naphthol hydrochloride (VK₅) has been studied by de and ac polarography in order to determine the applicability of these methods to the determination of VK₅ in aqueous solution. VK₅ exhibits two well-defined anodic waves on dc polarograms, one of which is due to the oxidation of VK₅ to the corresponding quinoimine and the other, to the formation of mercurous chloride on a dropping mercury electrode. Complete preremoval of dissolved oxygen makes the former wave reproducible, and its limiting current is found to be proportional to the VK₅ concentration ranging from 1.0 × 10^?5 to 1.0 × 10^?3m. On ac polarograms, electrooxidation of VK₅ also gives rise to a distinct peak whose height is proportional to the VK₅ concentration in the range of 5.0 × 10^?7 to 1.0 × 10^?5m. These facts can be applied to the microdetermination of VK₅ present in concentrations as low as the 0.1-ppm range.     

Evaluation of high sensitive C-reactive protein and 5-10 methylenetetrahydrofolate reductase genotype in Japanese young adults

Primary objective: To carry out a preliminary evaluation of subclinical inflammation and its genetic background in young adults.

Research design: Fifty-five healthy Japanese young adults aged 19–27 years (37 males and 18 females, mean age: 22.3 years), and 58 healthy Japanese adults aged 40 to 60 years (21 males and 37 females, mean age: 51.5 years) were included in this study.

Methods and procedures: We measured plasma high-sensitive C-reactive protein (hs-CRP) levels and screened for the C677T polymorphism of the 5-10 methylenetetrahydrofolate reductase gene (MTHFR), which is considered a genetic risk factor for atherosclerosis, by HinfI digestion.

Main outcomes and results: Hs-CRP levels of the young adult group were significantly lower than the levels of the middle aged group (0.014±0.030 mg/dl vs. 0.031±0.040 mg/dl, p=0.005). The levels were significantly higher in males than in females (0.028±0.019 mg/dl vs. 0.013±0.010 mg/dl, p=0.008) among young adults. Furthermore, we evaluated the relationship of the C677T genotype and hs-CRP values, but found no association between them.

Conclusions: Although the sample size is limited, our preliminary study demonstrated the profiles of hs-CRP in Japanese young adults. Further investigation will be needed to establish the guidelines for customized school health education using sensitive laboratory and genetic markers.     

A 3D-Video-Based Computerized Analysis of Social and Sexual Interactions in Rats

A large number of studies have analyzed social and sexual interactions between rodents in relation to neural activity. Computerized video analysis has been successfully used to detect numerous behaviors quickly and objectively; however, to date only 2D video recording has been used, which cannot determine the 3D locations of animals and encounters difficulties in tracking animals when they are overlapping, e.g., when mounting. To overcome these limitations, we developed a novel 3D video analysis system for examining social and sexual interactions in rats. A 3D image was reconstructed by integrating images captured by multiple depth cameras at different viewpoints. The 3D positions of body parts of the rats were then estimated by fitting skeleton models of the rats to the 3D images using a physics-based fitting algorithm, and various behaviors were recognized based on the spatio-temporal patterns of the 3D movements of the body parts. Comparisons between the data collected by the 3D system and those by visual inspection indicated that this system could precisely estimate the 3D positions of body parts for 2 rats during social and sexual interactions with few manual interventions, and could compute the traces of the 2 animals even during mounting. We then analyzed the effects of AM-251 (a cannabinoid CB1 receptor antagonist) on male rat sexual behavior, and found that AM-251 decreased movements and trunk height before sexual behavior, but increased the duration of head-head contact during sexual behavior. These results demonstrate that the use of this 3D system in behavioral studies could open the door to new approaches for investigating the neuroscience of social and sexual behavior.