Effects of 6- and 8-substituted analogs of adenosine 3':5'-monophosphate on phosphoenolpyruvate carboxykinase and tyrosine aminotransferase in hepatoma cell cultures.

A variety of 6- and 8-substituted analogs of cAMP (cyclic adenosine 3:5-monophosphate) have been tested for their ability to increase activity of tyrosine aminotransferase (EC 2.6.1.5) in cultured Reuber H35 hepatoma cells. Some analogs, particularly the 8-thio-substituted ones, produced effects approximately equivalent to those generated by N-6, O2'-dibutyryl cAMP. In contrast, cAMP and its O-2-monobutyryl derivative were relatively ineffective even at very high concentrations, whereas three other analogs actually depressed the activity of the aminotransferase. Changes in enzyme activity generated by the various analogs were paralleled closely by changes in the relative rate of aminotransferase synthesis. An excellent correlation was found to exist between the ability of any given analog to influence the activity of tyrosine aminotransferase and that of phosphoenolpyruvate carboxykinase (EC 4.1.1.32). A similar correlation was found to exist between the ability of various analogs to evelate the activity of these enzymes and to inhibit reversibly the growth of H35 cells. Only one of five inhibitors of cAMP phosphodiesterase activity tested produce any increase in aminotransferase activity when added alone. All of the 6- and 8-substituted analogs tested, including noniducers, stimulated f1 histone phosphorylation in crude rat liver extracts with approximately equal potencies. On the other hand, dibutyryl cAMP was only a weak activator of protein kinase in vitro, even though it is a potent enzyme inducer. A possible resolution of this apparent discrepancy has been provided by preliminary analyses of site-specific f1 histone phosphorylation in whole cells. Only compounds active as aminotransferase inducers are capable of stimulating phosphorylation of the serine-37 residue of endogenous f1 histone (3- to 10-fold).     

Comparison of fibreoptic endoscopy in acute upper gastrointestinal haemorrhage in Africans and Europeans.

The results of endoscopy in acute upper gastrointestinal haemorrhage were compared in a group of 138 Africans and one of 84 Europeans. Contrary to widely held clinical opinion, the incidence of gastric and duodenal ulceration was similar in the two races. Peptic ulcers were the main source of bleeding in both groups and were surprisingly more common than varices in the Africans. Bleeding from varices, however, was far more common in the Africans than in the Europeans. Stomal ulcers were confined to Europeans. Gastric erosions, often attributed to herbal medicines, were more common in the Africans but the difference was not significant. The study was not designed to determine reduced mortality since the introduction of endoscopy, but management, especially in the Africans, was aided by early recognition of haemorrhage from oesophageal varices and acute gastric erosions.     

Tuberculosis: Hospitalization and Outpatient Treatment

Initial hospitalization terminated by discharge upon medical advice to continue with chemotherapy on an outpatient basis represents the treatment of choice for most patients with active pulmonary tuberculosis. Any departure from this plan for any patient should be accepted only after careful consideration of all the circumstances. Patients with active pulmonary tuberculosis who are to receive outpatient chemotherapy without adequate initial hospitalization should be carefully selected by the local or provincial department of public health. Approval in writing should be required from the appropriate public health authority before antituberculosis chemotherapy is provided at public expense for any such patient, except possibly for a limited period while awaiting formal approval. In all instances, the clinic which dispenses the antituberculosis drugs should have the patient under supervision with recall for follow-up examinations as required. Prophylactic antituberculosis chemotherapy may be provided to certain groups of persons without hospitalization.     

Tidal downwelling and implications for the carbon biogeochemistry of cold‐water corals in relation to future ocean acidification and warming

Cold‐water coral (CWC) reefs are recognized as ecologically and biologically significant areas that generate habitats and diversity. The interaction between hydrodynamics and CWCs has been well studied at the Mingulay Reef Complex, a relatively shallow area of reefs found on the continental shelf off Scotland, UK. Within ‘Mingulay Area 01’ a rapid tidal downwelling of surface waters, brought about as an internal wave, is known to supply warmer, phytoplankton‐rich waters to corals growing on the northern flank of an east‐west trending seabed ridge. This study shows that this tidal downwelling also causes short‐term perturbations in the inorganic carbon (C_T) and nutrient dynamics through the water column and immediately above the reef. Over a 14 h period, corresponding to one semi‐diurnal tidal cycle, seawater pH overlying the reef varied by ca. 0.1 pH unit, while pCO₂ shifted by >60 μatm, a shift equivalent to a ca. 25 year jump into the future, with respect to atmospheric pCO₂. During the summer stratified period, these downwelling events result in the reef being washed over with surface water that has higher pH, is warmer, nutrient depleted, but rich in phytoplankton‐derived particles compared to the deeper waters in which the corals sit. Empirical observations, together with outputs from the European Regional Shelf Sea Ecosystem Model, demonstrate that the variability that the CWC reefs experience changes through the seasons and into the future. Hence, as ocean acidification and warming increase into the future, the downwelling event specific to this site could provide short‐term amelioration of corrosive conditions at certain times of the year; however, it could additionally result in enhanced detrimental impacts of warming on CWCs. Natural variability in the C_T and nutrient conditions, as well as local hydrodynamic regimes, must be accounted for in any future predictions concerning the responses of marine ecosystems to climate change.     

Multiple effects of temperature,photoperiod and food quality on the performance of a pine sawfly

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High-activity enzyme-polyurethane coatings

The synthesis of water-borne polyurethane coatings in the presence of diisopropylfluorophosphatase (DFPase, E.C. 3.8.2.1) enabled the irreversible attachment of the enzyme to the polymeric matrix. The distribution of immobilized DFPase as well as activity retention are homogeneous within the coating. The resulting enzyme-containing coating (ECC) film hydrolyzes diisopropylfluorophosphate (DFP) in buffered media at high rates, retaining approximately 39% intrinsic activity. Decreasing ECC hydrophilicity, via the use of a less hydrophilic polyisocyanate during polymerization, significantly enhanced the intrinsic activity of the ECC. DFPase-ECC has biphasic deactivation kinetics, where the initial rapid deactivation of DFPase-ECC leads to the formation of a hyperstable and active form of enzyme.     

Industrial microbiology of solar salt production

Solar salterns can be modeled as giant outdoor chemostats, much like a series of dams on a slow-moving river. Microorganisms and their products play an essential, but sometimes uncharacterized, role in salt production in these ponds, from seawater salinity up through NaCl saturation. They may physically affect the evaporation process and their by-products may chemically modify or bind with dissolved ions. Many solar salt facilities engage microbiologists to establish monitoring programs for analyses of nutrients, standing crop and associated biological variables in the ponds. Other solar salt companies engage microbiologists only when there are “crises” in the ponds that interfere with salt production. Journal of Industrial Microbiology & Biotechnology (2002) 28, 42–47 DOI: 10.1038/sj/jim/7000173 Received 20 May 2001/ Accepted in revised form 13 June 2001     

Targeted insertion of a lacZ reporter gene into the mouse Cer1 locus reveals complex and dynamic expression during embryogenesis

The mouse Cer1 (mCer1, Cer-l, Cerr1) gene encodes one member of a family of cytokines structurally and functionally related to the Xenopus head-inducing factor, Cerberus (xCer). We generated a mouse line in which the Cer1 gene was inactivated by replacing the first coding exon with a lacZ reporter gene. Mice homozygous for this allele (Cer1(lacZ)) showed no apparent perturbation of embryogenesis or later development. However, the lacZ reporter revealed a number of hitherto uncharacterised sites of Cer1 expression in late fetal and adult tissues. Preliminary analysis suggests that Cer1 is not essential for their morphogenesis, differentiation, or homeostasis.     

Rapid and unexpected effects of piscivore introduction on trophic position and diet of perch (Perca flavescens) in lakes recovering from acidification and metal contamination

1. Yellow perch (Perca flavescens) are often the only surviving fish species in acidified lakes. We studied four lakes along a gradient of recovery from acidification and that had different food web complexities. All had abundant yellow perch, two had low piscivore abundance, one had a well‐established piscivore population and one was manipulated by introducing piscivorous smallmouth bass (Micropterus dolomieu). We hypothesised that there would be strong effects on perch abundance, behaviour and diet induced by the presence of piscivores. 2. In the manipulated lake, the bass reduced yellow perch abundance by 75% over a 2‐year period. Concomitantly, perch use of the pelagic habitat fell from 48 to 40%. 3. In contrast to findings from less disturbed systems, yellow perch in the littoral zone of the manipulated lake did not strongly shift from zooplankton to benthic food sources after the arrival of piscivores. Diet analysis using stable carbon isotopes revealed a strong continued reliance on zooplankton in all lakes, independent of the degree of piscivory. The failure to switch to benthos in the refuge area of the littoral zone is most likely related to the depauperate benthos communities in these formerly acidified lakes. 4. Yellow perch in lakes recovering from acidification face a considerable ecological challenge as the necessary switch to benthic diet is hindered by a low abundance of benthos. The arrival of piscivores in these recovering lakes imposes further restrictions on perch access to food items. We infer that future recovery of perch populations (and higher trophic levels) will have to be preceded by the re‐establishment of diverse benthic macroinvertebrate communities in these lakes.     

Rheumatoid arthritis patients receive less frequent acute reperfusion and secondary prevention therapy after myocardial infarction compared with the general population

Introduction  

The 30-day case-fatality rate after acute myocardial infarction (MI) for rheumatoid arthritis (RA) patients is twice that of the general population. This study compared the frequency and timeliness of early reperfusion therapy and treatment with secondary prevention medications after acute MI in RA patients and controls.