Effects of guanidine on synaptic transmission in the spinal cord of the frog

The effects of guanidine on motoneurons of the isolated frog spinal cord were studied by adding the drug to the solution bathing the cord during intracellular recording. Guanidine (5·10–4 M) did not alter the membrane potential of motoneurons. The main effect was a marked increase of the amplitudes and frequencies of small spontaneously occurring inhibitory postsynaptic potentials. The hyperpolarizing component of postsynaptic potentials evoked by stimulation of dorsal roots was also enhanced by guanidine. Higher concentrations of guanidine (5·10–3 M) resulted in a very large and irreversible increase of the small spontaneously occurring inhibitory potentials, which now appeared in a regular, rhythmic pattern. The effects of guanidine could easily be blocked by increasing the magnesium ions (15 mM) in the bath solution. These results indicate that guanidine facilitates the release of an inhibitory transmitter in afferent terminals of the frog spinal cord either by a direct action on these terminals or indirectly by an action on nerve endings impinging on inhibitory interneurons

Проектирование технологического процесса изготовления детали «Шестерня 2-ой передачи»

Технологический процесс изготовления шестерни второй передачи, разработка приспособления для зубофрезерования.The technological process of manufacturing gear second gear, the development of devices for gear milling

Gender and sexual orientation differences in cognition across adulthood : age is kinder to women than to men regardless of sexual orientation

Despite some evidence of greater age-related deterioration of the brain in males than in females, gender differences in rates of cognitive aging have proved inconsistent. The present study employed web-based methodology to collect data from people aged 20-65 years (109,612 men; 88,509 women). As expected, men outperformed women on tests of mental rotation and line angle judgment, whereas women outperformed men on tests of category fluency and object location memory. Performance on all tests declined with age but significantly more so for men than for women. Heterosexuals of each gender generally outperformed bisexuals and homosexuals on tests where that gender was superior; however, there were no clear interactions between age and sexual orientation for either gender. At least for these particular tests from young adulthood to retirement, age is kinder to women than to men, but treats heterosexuals, bisexuals, and homosexuals just the same

Measuring changes in Schlemm’s canal and trabecular meshwork in different accommodation states in myopia children: an observational study

Abstract Purpose: Studies were designed to evaluate changes in the size of the Schlemm's Canal (SC) and trabecular meshwork(TM) during accommodation stimuli and cycloplegia states in myopic children. Methods: 34 children were enrolled. A -6D accommodation stimulus was achieved by looking at an optotype through a mirror. Cycloplegia state was induced with 1% tropicamide. Two states were confirmed by measuring the central lens thickness（CLT）, the anterior chamber depth and the pupil diameter. The size of the Schlemm's Canal (SC) and Trabecular Meshwork(TM) was measured using swept-source optical coherence tomography. And the associations between the change of the SC and the CLT were analyzed. Results: When compared with the relaxation state, under -6D accommodation stimuli, the size of SC increased significantly: the SC area (SCA) amplified from 6371±2517μm2 to 7824±2727 μm2; the SC length (SCL) from 249±10 μm to 295±12 μm, and SC width (SCW) from 27±9 μm to 31±8 μm. Under cycloplegia state, the SCA reduced to 5009±2028 μm2; the SCL to 212±μm and the SCW to 22±5 μm. In addition, the changed areas of SCA (r=0. 35; P=0.0007), SCL (r=0. 251; P=0.0172), and SCW (r=0. 253; P=0.016) were significantly correlated with the change in CLT. However, the size of TM did not change substantially when compared with the relaxation state. Only the TM length (TML) increased from 562±45μm to 587±47μm after -6D accommodation stimulus. Conclusion: SC size enlarges after -6D accommodation stimuli and shrinks under cycloplegia. However, for TM, only the TM length increase under accommodation stimulus state. KEYWORDS: Schlemm’s Canal, Trabecular Meshwork, accommodatio

A Comprehensive Profile of Decoding and Comprehension in Autism Spectrum Disorders

The present study examined intake data from 384 participants with autism spectrum disorders (ASD) and a comparison group of 100 participants with dyslexia on nine standardized measures of decoding and comprehension. Although diagnostic groups were based on parental reports and could not be verified independently, we were able to observe significant distinctions between subject groups. Overall findings confirm previous results of a disassociation between decoding and comprehension in ASD. Using a larger sample than previous studies and a greater variety of measures, a pattern of relatively intact decoding skills paired with low comprehension was found in autism, PDD-NOS, and Asperger’s. In contrast, the dyslexic group showed the opposite pattern of stronger comprehension and weaker decoding

Performance of elementary grade African American students on the Gray Oral Reading Tests

http://deepblue.lib.umich.edu/bitstream/2027.42/83318/1/Performance_of_elementary_grade_African_American_students_on_the_Gray_Oral_Reading_Tests.pd

Targeted Curing of All Lysogenic Bacteriophage from Streptococcus pyogenes Using a Novel Counter-selection Technique

We thank the members of the Laboratory of Microbial Pathogenesis and Immunology, especially Annette Nelkenbaum and Ben Winer for their technical assistance. We also thank Estee Colleen Cervantes and Sutapa Banerjee from Hunter College for their technical contribution to this project. We are grateful to Joseph Ferretti for S. pyogenes strain SF370.Streptococcus pyogenes is a human commensal and a bacterial pathogen responsible for a wide variety of human diseases differing in symptoms, severity, and tissue tropism. The completed genome sequences of >37 strains of S. pyogenes, representing diverse disease-causing serotypes, have been published. The greatest genetic variation among these strains is attributed to numerous integrated prophage and prophage-like elements, encoding several virulence factors. A comparison of isogenic strains, differing in prophage content, would reveal the effects of these elements on streptococcal pathogenesis. However, curing strains of prophage is often difficult and sometimes unattainable. We have applied a novel counter-selection approach to identify rare S. pyogenes mutants spontaneously cured of select prophage. To accomplish this, we first inserted a two-gene cassette containing a gene for kanamycin resistance (KanR) and the rpsL wild-type gene, responsible for dominant streptomycin sensitivity (SmS), into a targeted prophage on the chromosome of a streptomycin resistant (SmR) mutant of S. pyogenes strain SF370. We then applied antibiotic counter-selection for the re-establishment of the KanS/SmR phenotype to select for isolates cured of targeted prophage. This methodology allowed for the precise selection of spontaneous phage loss and restoration of the natural phage attB attachment sites for all four prophage-like elements in this S. pyogenes chromosome. Overall, 15 mutants were constructed that encompassed every permutation of phage knockout as well as a mutant strain, named CEM1ΔΦ, completely cured of all bacteriophage elements (a ~10% loss of the genome); the only reported S. pyogenes strain free of prophage-like elements. We compared CEM1ΔΦ to the WT strain by analyzing differences in secreted DNase activity, as well as lytic and lysogenic potential. These mutant strains should allow for the direct examination of bacteriophage relationships within S. pyogenes and further elucidate how the presence of prophage may affect overall streptococcal survival, pathogenicity, and evolution.Yeshttp://www.plosone.org/static/editorial#pee

Regulation of intracellular pH in cultured bovine retinal pigment epithelial cells

Regulation of intracellular pH (pHi) in bovine retinal pigment epithelium (RPE) was investigated in cell culture. pHi was measured using the pH-sensitive absorbance of intracellularly trapped 5 (and 6)-carboxy-dimethyl-fluorescein (CDMF). (1) Regulation of pHi after induction of an acid load by removal of NH4Cl could be blocked either totally by removal of extracellular sodium, or subtotally (about 90%) by application of amiloride (1 mmol/l). Additional flux measurements revealed a dose-dependent, amiloride-sensitive 22Na+-uptake into Na+-loaded cells. Both results suggest the presence of a Na+/H+ antiport. (2) When alkalinization of the cells was induced by preincubation with 50 mmol/l acetate in HCO3(-)-Ringer's and subsequent removal of the weak acid, the following regulation was dependent on the presence of extracellular chloride. This process could be blocked with DIDS (1 mmol/l), suggesting the presence of a Cl-/HCO3- exchange mechanism. (3) We found no evidence for a Na+/HCO3(-)-cotransport, which had been postulated to be present in RPE by others. We conclude that two processes are involved in regulation of pHi in RPE: A Na+/H+ antiport responsible for recovery of pHi from acid load, and a DIDS-sensitive Cl-/HCO3- exchange mechanism responsible for recovery of pHi after alkalinization