Cell-cell interactions in the control of spermatogenesis as studied using Leydig cell destruction and testosterone replacement

This review centers around studies which have used ethane dimethane sulphonate (EDS) selectively to destroy all of the Leydig cells in the adult rat testis. With additional manipulations such as testosterone replacement and/or experimental induction of severe seminiferous tubule damage in EDS-injected rats, the following questions have been addressed: 1) What are the roles and relative importance of testosterone and other non-androgenic Leydig cell products in normal spermatogenesis and testicular function in general? 2) What are the factors controlling Leydig cell proliferation and maturation? 3) Is it the Leydig cells or the seminiferous tubules (or both) which control the testicular vasculature? The findings emphasize that in the normal adult rat testis there is a complex interaction between the Leydig cells, the Sertoli (and/or peritubular) cells, the germ cells, and the vasculature, and that testosterone, but not other Leydig cell products, plays a central role in many of these interactions. The Leydig cells drive spermatogenesis via the secretion of testosterone which acts on the Sertoli and/or peritubular cells to create an environment which enables normal progression of germ cells through stage VII of the spermatogenic cycle. In addition, testosterone is involved in the control of the vasculature, and hence the formation of testicular interstitial fluid, presumably again via effects on the Sertoli and/or peritubular cells. When Leydig cells regenerate and mature after their destruction by EDS, it can be shown that both the rate and the location of regenerating Leydig cells is determined by an interplay between endocrine (LH and perhaps FSH) and paracrine factors; the latter emanate from the seminiferous tubules and are determined by the germ cell complement. Taken together with other data on the paracrine control of Leydig cell testosterone secretion by the seminiferous tubules, these findings demonstrate that the functions of all of the cell types in the testis are interwoven in a highly organized manner. This has considerable implications with regard to the concentration of research effort on in vitro studies of the testis, and is discussed together with the need for a multidisciplinary approach if the complex control of spermatogenesis is ever to be properly understood.     

Wool Fibres: Sectioning and Staining, Differentiation of Ortho and Paracortex

A double embedding technique for tangential sectioning of hair and wool fibres is as follows: The cleaned fibre bundle is attached to a U-shaped, 16 gauge, tinned-copper wire frame with collodion adhesive, soaked in 6% nitrocellulose for 1 hr, and treated with chloroform for 2 hr. The hardened bundle is then cut fom the wire support and embedded in paraffin-beeswax, 95:5. Sectioning is at 6-8 μ. The use of 2% orange G or saturated aqueous picric acid for quantitative study of the fibres, and the demonstration of wool fibre cortical fractions by staining with polychrome methylene blue after oxidation of the sectioned fibres in a solution of formic acid (98/100 w/v) 25 ml; distilled water, 65 ml; and H₂O₂ (30% w/v), 10 ml, for 1 hr, is recommended.     

Poor physical fitness is independently associated with mild cognitive impairment in elderly Koreans

The purpose of this study was to investigate the association between physical fitness and mild cognitive impairment (MCI) in elderly Koreans. This was a cross-sectional study that involved 134 men and 299 women aged 65 to 88 years. Six senior fitness tests were used as independent variables: 30 s chair stand for lower body strength, arm curl for upper body strength, chair-sit-and-reach for lower body flexibility, back scratch for upper body flexibility, 8-ft up-and-go for agility/dynamic balance, and 2-min walk for aerobic endurance. Global cognitive function was assessed using the Korean version of the Mini-Mental State Examination (MMSE). Potential covariates such as age, education levels, blood lipids, and insulin resistance (IR) markers were also assessed. Compared to individuals without MMSE-based MCI, individuals with MMSE-based MCI had poor physical fitness based on the senior fitness test (SFT). There were significant positive trends observed for education level (p=0.001) and MMSE score (p<0.001) across incremental levels of physical fitness in this study population. Individuals with moderate (OR=0.341, p=0.006) and high (OR=0.271, p=0.007) physical fitness based on a composite score of the SFT measures were less likely to have MMSE-based MCI than individuals with low physical fitness (referent, OR=1). The strength of the association between moderate (OR=0.377, p=0.038) or high (OR=0.282, p=0.050) physical fitness and MMSE-based MCI was somewhat attenuated but remained statistically significant even after adjustment for the measured compounding factors. We found that poor physical fitness was independently associated with MMSE-based MCI in elderly Koreans.     

Seasonal use of torpor by free-ranging Australian owlet-nightjars (Aegotheles cristatus)

With the exception of some data for common poorwills (Phalaenoptilus nuttallii) and anecdotal reports for a few other species, knowledge about the use of torpor by free-ranging birds is limited. Our study was designed to assess the use of torpor by free-ranging Australian owlet-nightjars (Aegotheles cristatus). We selected this species for study because of their relatively small body size (50 g), arthropod diet, nocturnal sedentary nature, taxonomic affiliation with other birds for whom the use of torpor is well documented, use of cavity roosts, and because of the cold winter (mean July minimum ambient temperature [T(a)] of approximately 0 degrees C) in the study area. We tracked 12 owlet-nightjars carrying temperature-sensitive transmitters for a total of 906 bird-days (range of 15-115 d per individual). Five different individuals entered torpor on 96 d in total. Torpor bouts occurred only between May 8 and September 8, the coldest period of the year. The lowest skin temperature (T(skin)) recorded for any bird was 19.6 degrees C, and the lowest core temperature was 22.4 degrees C. Surprisingly, torpor was rarely used at night because birds usually foraged then. Instead, torpor typically began near dawn, even on cold nights. Torpor bouts beginning at dawn lasted approximately 4 h. On 36% of days when torpor was used at dawn, birds reentered torpor later in the day. Torpor was not used during the breeding season, but this period also corresponds to the warm part of the year. There were no distinct daily minimum, maximum, or mean T(a) thresholds that could be used to reliably distinguish days when dawn torpor was used from those when it was not, although torpor was commonly employed when daily minimum T(a) fell below 3.9 degrees C. Our results show that even though Australia is typically thought of as a warm continent, at least some of the avifauna use torpor as a regular means of saving energy. We hypothesise that the reasons for this species' use of torpor include its ability to remain active all night foraging, either for terrestrial arthropods while walking or for flying insects taken on the wing, and/or its habit of roosting in cavities, which allows them to remain hidden in the daytime.     

Molecular docking analysis of glycogen phosphorylase with inhibitors from Cissampelos pareira Linn.

Cissampelos pareira Linn. is a climbing herb known in Indian traditional medicine as laghupatha. It belongs to the Menispermaceae family. The enzyme glycogen phosphorylase (GP) is a promising target for the treatment of type-2 diabetes (T2DM). A variety of natural product inhibitors with both pharmaceutical and nutraceutical potential have been reported in the search for powerful, selective and drug-like GP inhibitors that could lead to hypoglycemic medicines. Therefore, it is of interest to document the molecular docking analysis data of glycogen phosphorylase with compounds from Cissampelos pareira Linn. We report the optimal binding features of 4 compounds namely Trans-N-feruloyltyramine, Coclaurine, Magnoflorine, and Curine with the target protein for further consideration in the context of T2DM.     

Do Children Who Move Home and School Frequently Have Poorer Educational Outcomes in Their Early Years at School? An Anonymised Cohort Study

Frequent mobility has been linked to poorer educational attainment. We investigated the association between moving home and moving school frequently and the early childhood formal educational achievement. We carried out a cohort analysis of 121,422 children with anonymised linked records. Our exposure measures were: 1) the number of residential moves registered with a health care provider, and 2) number of school moves. Our outcome was the formal educational assessment at age 6–7. Binary regression modeling was used to examine residential moves within the three time periods: 0 – <1 year; 1 – <4 years and 4 – <6 years. School moves were examined from age 4 to age 6. We adjusted for demographics, residential moves at different times, school moves and birth related variables. Children who moved home frequently were more likely not to achieve in formal assessments compared with children not moving. Adjusted odds ratios were significant for 3 or more moves within the time period 1 –<4 years and for any number of residential moves within the time period 4–<6 years. There was a dose response relationship, with increased odds ratios with increased frequency of residential moves (2 or more moves at 4–<6 years, adjusted odds ratio 1.16 (1.03, 1.29). The most marked effect was seen with frequent school moves where 2 or more moves resulted in an adjusted odds ratio of 2.33 (1.82, 2.98). This is the first study to examine the relationship between residential and school moves in early childhood and the effect on educational attainment. Children experiencing frequent mobility may be disadvantaged and should be closely monitored. Additional educational support services should be afforded to children, particularly those who frequently change school, in order to help them achieve the expected educational standards.     

Body mass regulation in response to changes in feeding predictability and overnight energy expenditure

Feeding and fat storage entail both costs and benefits. Benefitsinclude minimizing the risk of starvation; costs include mass-dependentcosts of locomotion and predation risk. An understanding ofthese costs and benefits is relevant not only to explanationsof foraging patterns and fat storage, but to hoarding decisions,migration strategies, and population dynamics. Despite predictionsfrom theoretical models, empirical tests of the assumptionsand predictions of models have been tested only recently. However,published experiments on the effects of unpredictability haveoften confounded manipulations of mean, variability, and predictabilityof the food supply, all of which are predicted to affect foragingintensity and fat storage. In experiments on European starlings,Sturnus vulgaris, we manipulated the predictability of thefood supply while holding the mean and average variabilityconstant. We did this in conjunction with manipulation of overnightenergy expenditure via simulated nocturnal wind exposure. Both greater unpredictability of food availability and higher overnightenergy expenditure increased daily mass gain and dusk (leanand fat) mass, but in a purely additive fashion. Dawn massonly changed in response to predictability, not overnight energyexpenditure. By introducing a probe day, with identical feedingexperience for all treatments, we ascertained that the responseto predictability was based on experience integrated over morethan a single day.     

MTT assay based inhibition analysis of A2780 cells proliferation using Mollugo nudicaulis Lam. extract with CXCR4 and HER2 expression

It is of interest to document the inhibition of A2780 cell proliferation using Mollugo nudicaulis Lam.(M.nudicaulis) extract by MTT assay and by monitoring the CXCR4 and HER2 expression through RT-PCR analysis. Results shown that the n-hexane extract of M.nudicaulis have anticancer activity IC₅₀ values of 32.46±0.92 µg/mL on A2780 cell lines. It is further found that the CXCR4 and HER2 mRNA and protein expression were significantly reduced in M.nudicaulis treated A2780 cell lines. Thus, the n-hexane extract of M.nudicaulis is a natural source of bioactive compounds as potential anticancer agents.