Chemical sterilization of male langurs: synergistic action of alpha-chlorohydrin (U-5897) with methallibure (ICI, 33828) on the testes and epididymides of Presbytis entellus entellus Dufresne.

1. Synergistic action of alpha-chlorohydrin with methallibure (ICI, 33828) on the testicular function of Presbytis entellus entellus Dufresne has been studied. 2. Chronic administration of alpha-chlorohydrin alone (140 mg/day for 40 days) caused testicular lesion resulting in a massive atrophy of the spermatogenic elements. Epididymal epithelium was regressed and the lumen was devoid of spermatozoa. 3. alpha-Chlorohydrin inhibited the synthesis of RNA and sialic acid in the testes and epididymides. Total cholesterol per gram of testis and alkaline phosphatase activity were increased after alpha-chlorohydrin administration. 4. These effects could be achieved with a lower dose of alpha-chlorohydrin (1/4) when administered in combination with a gonadotrophin inhibitor, i. e. ICI, 33828 (Methallibure). Methallibure alone (200 mg/kg: total dose) has no damaging effects on the testes and epididymides. But it altered testicular cholesterol and enzyme activity. 5. In conclusion, an effective inhibition of spermatogenesis could be achieved by synergistic action of the two different drugs i. e. alpha-chlorohydrin and ICI, 33828 (Methallibure).     

A Novel in vivo Gene Transfer Technique and in vitro Cell Based Assays for the Study of Bone Loss in Musculoskeletal Disorders

Differentiation and activation of osteoclasts play a key role in the development of musculoskeletal diseases as these cells are primarily involved in bone resorption. Osteoclasts can be generated in vitro from monocyte/macrophage precursor cells in the presence of certain cytokines, which promote survival and differentiation. Here, both in vivo and in vitro techniques are demonstrated, which allow scientists to study different cytokine contributions towards osteoclast differentiation, signaling, and activation. The minicircle DNA delivery gene transfer system provides an alternative method to establish an osteoporosis-related model is particularly useful to study the efficacy of various pharmacological inhibitors in vivo. Similarly, in vitro culturing protocols for producing osteoclasts from human precursor cells in the presence of specific cytokines enables scientists to study osteoclastogenesis in human cells for translational applications. Combined, these techniques have the potential to accelerate drug discovery efforts for osteoclast-specific targeted therapeutics, which may benefit millions of osteoporosis and arthritis patients worldwide.     

Tracking Recovery Patterns in Acidified Lakes: A Paleolimnological Perspective

Long-term data are often lacking to effectively assess patterns of lake acidification and recovery. Fortunately, paleolimnological techniques can be used to infer past changes in lakewater acidity and related variables by means of biological indicators, such as diatom valves and chrysophyte scales, preserved in ²¹⁰Pb-dated sediment cores. We summarize paleolimnological data that we have gathered from 36 Sudbury (Ontario) and 20 Adirondack Park (New York) lakes to estimate the magnitude of lake acidification and any subsequent recovery in these lake systems. In both regions, many lakes were shown to have acidified considerably, some over two pH units, since the 1850s. Although some recovery was noted in both lake regions, Sudbury lakes generally showed larger increases in inferred lakewater pH with recent declines in sulfur emissions. Possible explanations of these differences include the greater decrease in sulfate deposition in the Sudbury area, as well as generally longer residence times of lakes in Sudbury, perhaps allowing for more in-lake alkalinity generation. In addition, Sudbury lakes generally had higher pre-industrial pH levels, suggesting that lakes with higher natural buffering capacities are more likely to recover more quickly with declines in deposition, even if they had been acidified to a great extent.