Stereo Dissecting Microscope
all about Stereo Dissecting MicroscopeMedicine From Milk: Gene Therapy Could Transform Goats Into Pharmaceutical Factories
Medicine From Milk: Gene Therapy Could Transform Goats Into Pharmaceutical Factories
Click Here to read the entire article...
Other Articles:
| • | Opposing effects of D-aspartic acid and nitric oxide on tuning of testosterone production in mallard testis during the reproductive cycle |
| Background: D-Aspartic acid (D-Asp) and nitric oxide (NO) play an important role in tuning testosterone production in the gonads of male vertebrates. In particular, D-Asp promotes either the synthesis or the release of testosterone, whereas NO inhibits it. In this study, we have investigated for the first time in birds the putative effects of D-Asp and NO on testicular testosterone production in relation to two phases of the reproductive cycle of the adult captive wild-strain mallard (Anas platyrhynchos) drake. It is a typical seasonal breeder and its cycle consists of a short reproductive period (RP) in the spring (April-May) and a non reproductive period (NRP) in the summer (July), a time when the gonads are quiescent. The presence and the localization of D-Asp and NO in the testis and the trends of D-Asp, NO and testosterone levels were assessed during the main phases of the bird's reproductive cycle. Furthermore, in vitro experiments revealed the direct effect of exogenously administered D-Asp and NO on testosterone steroidogenesis. Methods: By using immunohistochemical (IHC) techniques, we studied the presence and the distributional pattern of D-Asp and NO in the testes of RP and NRP drakes. D-Asp levels were evaluated by an enzymatic method, whereas NO content, via nitrite, was assessed using biochemical measurements. Finally, immunoenzymatic techniques determined testicular testosterone levels. Results: IHC analyses revealed the presence of D-Asp and NO in Leydig cells. The distributional pattern of both molecules was in some way correlated to the steroidogenic pathway, which is involved in autocrine testosterone production. Indeed, whereas NO was present only during the NRP, D-Asp was almost exclusively present during the RP. Consistently, the high testosterone testicular content occurring during RP was coupled to a high D-Asp level and a low NO content in the gonad. By contrast, in sexually inactive drakes (NRP), the low testosterone content in the gonad was coupled to a low D-Asp content and to a relatively high NO level. Consequently, to determine the exogenous effects of the two amino acids on testosterone synthesis, we carried out in vitro experiments using testis sections deriving from both the RP and NRP. When testis slices were incubated for 60 or 120 min with D-Asp, testosterone was enhanced, whereas in the presence of L-Arg, a precursor of NO, it was inhibited. Conclusion: Our results provide new insights into the involvement of D-Asp and NO in testicular testosterone production in the adult captive wild-strain mallard drake. The localization of these two molecules in the Leydig cells in different periods of the reproductive cycle demonstrates that they play a potential role in regulating local testosterone production. | |
| Click Here to read the entire article... |
|
| • | The role of efavirenz compared with protease inhibitors in the body fat changes associated with highly active antiretroviral therapy |
|
Highly active antiretroviral therapy plays a central role in the development of lipodystrophy syndrome, which may affect up to 50% of patients depending on the diagnostic criteria used. Most protease inhibitors and nucleoside reverse transcriptase inhibitors (NRTIs) are involved in body fat changes and associated metabolic disturbances. In contrast, non-NRTIs have not been directly related to the onset of this syndrome. One of the most widely used methods to evaluate body fat changes is dual-energy X-ray absorptiometry (DEXA), which can detect differences in the distribution of body fat in patients with and without lipodystrophy. New information from a randomized open-label clinical trial suggests that efavirenz could have greater potential for causing lipoatrophy than lopinavir+ritonavir. This paper examines the impact of efavirenz on adipose tissue and body fat composition in order to evaluate whether this drug plays a role in the development of lipodystrophy. We have focused on the evidence obtained from comparative randomized clinical trials that use an objective measurement of fat distribution, such as DEXA. We analysed available in vitro data and evidence from non-comparative clinical trials. |
|
| Click Here to read the entire article... |
|
| • | "Nanosculpture" Could Enable New Types of Heat Pumps and Energy Converters |
| A new technique for growing single-crystal nanorods and controlling their shape using biomolecules could enable the development of smaller, more powerful heat pumps and devices that harvest electricity from heat. (2008-07-21) | |
| Click Here to read the entire article... |
|
| • | Fat Grafting Provides Permanent, Natural Looking Results - Dr. Michael Law Explains Fat Injections as a New Trend in Facial Plastic Surgery |
| Click Here to read the entire article... |
|
| • | Animal Dissection |
| A website dedicated to Animal Dissection. Get the latest articles, news and information updates on Animal Dissection from Animal Dissection. | |
| Click Here to read the entire article... |
|
| • | Optical microscope - Wikipedia, the free encyclopedia |
| The optical microscope, often referred to as the "light microscope", is a type of microscope which uses visible light and a system of lenses to magnify images of small samples. | |
| Click Here to read the entire article... |
|
- Copyright © 2008 Microsoft. All rights reserved. These XML results may not be used, reproduced or transmitted in any manner or for any purpose other than rendering Live Search results within an RSS aggregator for your personal, non-commercial use. Any other use of these results requires express written permission from Microsoft Corporation. By accessing this web page or using these results in any manner whatsoever, you agree to be bound by the foregoing restrictions. - version: v1.5 build A