Beta-adrenoceptor-blocking drugs and blood sugar control in diabetes mellitus.

The effects on diabetic control of the relative cardioselective beta-blocker metoprolol and the non-selective drug propranolol were compared in 20 hypertensive diabetic patients receiving diet alone or diet and oral hypoglycaemic agents. Each drug was given for one month in a double-blind, cross-over study. Fasting, noon, and mid-afternoon blood sugar concentrations rose by 1.0-1.5 mmol/l (18-27 mg/100 ml). The rise with propranolol was not significantly greater than with metoprolol. In a few patients the rise was clinically important. The small overall change observed in diabetic control should not deter the use of beta-blockers in non-insulin-dependent diabetics, provided control is carefully monitored at the onset of treatment.     

Cellulolytic Enzyme System of Thermoactinomyces sp. Grown on Microcrystalline Cellulose

The carboxymethyl-cellulase and Avicelase activities of Thermoactinomyces sp., strain YX, were produced simultaneously with cell growth. Throughout the growth phase these activities were primarily extracellular, with up to 50% adsorbed to residual cellulosic substrate at any one time. On the other hand, the β-glucosidase activity was associated with the culture solids throughout the entire fermentation and appears to be intracellular. Preparative isoelectric focusing of the culture filtrate, in the pH range 3 to 5, separated three major fractions with cellulolytic activities towards both carboxymethyl-cellulose and Avicel. Based on the carboxymethyl-cellulase and Avicelase activities of these separated fractions, it was not possible to discriminate between endo- and exoglucanases produced by Thermoactinomyces sp. Analytical isoelectric focusing of culture filtrates obtained throughout the growth phase of Thermoactinomyces indicated that all the extracellular cellulolytic enzymes are produced and released into the culture filtrate simultaneously, with no evidence of a sequential appearance of the various enzymes or isoenzymes.     

Newly synthesized norepinephrine accumulation in the readily releasable pool of a purified adrenergic vesicle fraction

A highly purified fraction of large dense core adrenergic vesicles was studied after isolation from bovine splenic nerve chilled within 10 to 12 minutes post mortem. In a standard medium containing 5 mM each of Mg⁺⁺ and ATP and 6 μM norepinephrine (NE), this vehicle fraction contained NE in a readily releasable and a more stable pool. When vesicle dopamine β-hydroxylase was activated with 1.33 mM ascorbic acid using 6 μM ¹⁴C-dopamine as substrate at 30°C, ¹⁴C-NE was synthesized at a linear rate during the 45 minute incubation. Net accumulation of NE (p < 0.01) and a proportional net retention of newly synthesized ¹⁴C-NE occurred only when the readily releasable pool could still be demonstrated. The halftime for the fast release pool was doubled from 3 to 6 minutes (p < 0.01) with no effect on the slower released, ATP-facilitated uptake pool. Thus, both during axoplasmic transport and induced NE synthesis $\text{in vitro}$, there is evidence that newly synthesized NE preferentially accumulates in the readily releasable pool, a property also characteristic of the physiologically active pool $\text{in vivo}$.     

A role for Bach1 and HO-2 in suppression of basal and UVA-induced HO-1 expression in human keratinocytes

Ultraviolet A (UVA) radiation is an oxidizing agent that strongly induces the heme oxygenase 1 (HO-1) gene and expression of the protein in cultured human skin fibroblasts but weakly induces it in skin keratinocytes. Lower basal levels of HO-1 and much higher basal levels of HO-2 protein are observed in keratinocytes compared with fibroblasts. Using both overexpression and knockdown approaches, we demonstrate that HO-2 modulates basal and UVA-induced HO-1 protein levels, whereas HO-1 levels do not affect HO-2 levels in skin fibroblasts and keratinocytes. Silencing of Bach1 strongly increases HO-1 levels in transformed HaCaT keratinocytes and these HO-1 levels are not further increased by either UVA irradiation or silencing of HO-2. This is consistent with the conclusion that high constitutive levels of HO-2 expression in keratinocytes are responsible for the resistance of these cells to HO-1 induction by UVA radiation and that Bach1 plays a predominant role in influencing the lack of HO-1 expression in keratinocytes. Bach1 inhibition leading to HO-1 induction reduced UVA-irradiation-induced damage as monitored both by the extent of LDH release and by nuclear condensation, so that Bach1 inhibition seems to protect against UVA-irradiation-induced damage in keratinocytes.     

Review of impact categories and environmental indicators for life cycle assessment of geotechnical systems

Life cycle assessment (LCA) has only had limited application in the geotechnical engineering discipline, though it has been widely applied to civil engineering systems such as pavements and roadways. A review of previous geotechnical LCAs showed that most studies have tracked a small set of impact categories, such as energy and global warming potential. Accordingly, currently reported environmental indicators may not effectively or fully capture important environmental impacts and tradeoffs associated with geotechnical systems, including those associated with land and soil resources. This research reviewed previous studies, methods, and models for assessment of land use and soil‐related impacts to understand their applicability to geotechnical LCA. The results of this review show that critical gaps remain in current knowledge and practice. In particular, further development or refinement of environmental indicators, impact categories, and cause–effect pathways is needed as they pertain to geotechnical applications—specifically those related to soil quality, soil functions, and the ecosystem services soils provide. In addition, many existing methods emerge from research on land use and land use change related to other disciplines (e.g., agriculture). For applicability to geotechnical projects, the resolution of many of these methods and resulting indicators need to be downscaled from the landscape/macro scale to the project scale. In the near term, practitioners of geotechnical LCA should begin tracking changes to soil properties and report impacts to land and soil resources qualitatively.     

Where old meets new: An ecosystem study of methanogenesis in a reflooded agricultural peatland

Reflooding formerly drained peatlands has been proposed as a means to reduce losses of organic matter and sequester soil carbon for climate change mitigation, but a renewal of high methane emissions has been reported for these ecosystems, offsetting mitigation potential. Our ability to interpret observed methane fluxes in reflooded peatlands and make predictions about future flux trends is limited due to a lack of detailed studies of methanogenic processes. In this study we investigate methanogenesis in a reflooded agricultural peatland in the Sacramento Delta, California. We use the stable‐and radio‐carbon isotopic signatures of wetland sediment methane, ecosystem‐scale eddy covariance flux observations, and laboratory incubation experiments, to identify which carbon sources and methanogenic production pathways fuel methanogenesis and how these processes are affected by vegetation and seasonality. We found that the old peat contribution to annual methane emissions was large (~30%) compared to intact wetlands, indicating a biogeochemical legacy of drainage. However, fresh carbon and the acetoclastic pathway still accounted for the majority of methanogenesis throughout the year. Although temperature sensitivities for bulk peat methanogenesis were similar between open‐water (Q₁₀ = 2.1) and vegetated (Q₁₀ = 2.3) soils, methane production from both fresh and old carbon sources showed pronounced seasonality in vegetated zones. We conclude that high methane emissions in restored wetlands constitute a biogeochemical trade‐off with contemporary carbon uptake, given that methane efflux is fueled primarily by fresh carbon inputs.