The Social Development Summit and the developing countries.
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Congresses as Topic↗
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Results for “Sustainable Development”
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Hemodynamic and electrophysiologic effects of encainide in patients with bundle branch block.
Electrophysiologic studies were performed in 6 consecutive patients with bundle branch block and organic heart disease. All were studied after intravenous (0.9 mg/kg) encainide and 3 of the 6 after 36-72 hours of oral encainide (50 mg every 6 hours). After intravenous encainide, mean H-Q increased from 51 +/- 20 msec to 58 +/- 25 msec (14% p less than or equal to .05). After oral encainide (3 patients) H-Q increased to 90 +/- 39 msec (56% p less than or equal to .05, compared to baseline). Programmed ventricular stimulation was performed in 5. In 1 patient without spontaneous ventricular tachycardia, tachycardia was non-inducible before and after encainide. Of 5 patients with spontaneous arrhythmia, 3 had ventricular tachycardia induced before and after intravenous encainide at mean cycle lengths of 287 +/- 130 msec and 407 +/- 261 msec, (not significant) respectively, while 1 had ventricular tachycardia induced only after encainide. Four patients began chronic treatment with oral encainide (2 patients with inducible rapid ventricular tachycardia after encainide were excluded). All suffered major adverse outcomes. One died suddenly after an electrophysiology study demonstrated inducible ventricular tachycardia, which occurred only after encainide. One experienced new syncope after baseline H-Q increased 75% after encainide. Two patients developed new sustained atrial tachycardias and 1 patient developed persistent ventricular tachycardia on encainide.(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗
Forces and powers of slow and fast skeletal muscles in mice during repeated contractions.
1. The normalized force or power developed during each of a series of repeated contractions was averaged over the entire cycle of activity and rest to provide a measure of performance referred to as sustained force or sustained power. We tested the hypotheses that compared with slow soleus muscles, fast extensor digitorum longus (EDL) muscles would attain lower maximum values of sustained force, but higher maximum values of sustained power. 2. During repeated contractions at a stimulation frequency of 150 Hz, forces and powers of soleus and EDL muscles of mice were determined in situ at 35 degrees C. The train rate of repeated contractions was incremented every 5 min to increase duty cycle until a maximum value for sustained force or power was reached. 3. In one set of repeated contractions, each contraction was preceded by a quick stretch and thereafter muscle length was held constant. The stretch minimized active shortening of muscle fibres. Sustained force was calculated from force at constant length. The maximum sustained force developed by soleus muscles of 4.58 +/- 0.31 N cm-2 (mean +/- S.E.M.) occurred at a duty cycle of 0.48. Compared with soleus muscles, EDL muscles attained a lower (P less than 0.05) maximum value of 1.38 +/- 0.15 N cm-2 at a 0.35 duty cycle. 4. During isovelocity shortening contractions, the maximum value for sustained power developed by soleus muscles of 7.4 +/- 0.5 W kg-1 occurred at a duty cycle of 0.18. Compared with soleus muscles, EDL muscles achieved a significantly greater maximum value of 9.1 +/- 0.4 W kg-1 at a 0.21 duty cycle.
Animals↗
Achieving sustainable agriculture through recognizing gender roles: some salient points.
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Agriculture↗
Development of a sustained-release system for perivascular delivery of dipyridamole.
Vascular access grafts implanted in dialysis patients are prone to failure in the long-term because of stenosis and occlusion caused by neointimal hyperplasia. Local delivery of antiproliferative drugs may be effective to prevent this consequence while minimizing the systemic side effects they cause. We developed a combination of poly(lactide-co-glycolide) (PLGA) microspheres with ReGel, an injectable copolymer, as a sustained-release system for perivascular delivery of an antiproliferative drug, dipyridamole. Dipyridamole-incorporated PLGA microspheres with various molecular weights (MWs) of PLGA were prepared by oil-in-water emulsion method. Encapsulation efficiency and surface morphology of microspheres were characterized. In vitro release kinetics of dipyridamole from ReGel or from microspheres/ReGel was experimentally determined. Without microspheres, 40% of the dipyridamole was released from ReGel as an initial burst in the first 3 days followed by continuous release in the subsequent 2 weeks. The use of PLGA microspheres decreased the initial burst and extended dipyridamole release from 23 to 35 days with increasing MW of PLGA. The highest MW PLGA showed a lag time of 17 days before consistent drug release occurred. Mixing microspheres and ReGel with two different MW PLGA achieved a continuous release for 35 days with little initial burst. In vivo release of dipyridamole from microspheres/ReGel exhibited a comparable release pattern to that seen in vitro. This injectable platform is a promising technique for sustained perivascular delivery of antiproliferative drugs.
Animals↗
Review of North-South and South-South cooperation and conditions necessary to sustain research capability in developing countries.
The paper extracted pertinent aspects of 21 years (1981-2001) of scientific cooperation among Zimbabwe's Blair Research Laboratory (BRL), the Biomedical Research and Training Institute (BRTI), and the Danish Bilharziasis Laboratory (DBL). DBL supported the building of research capacity at BRL through PhD-level training and short courses on research training organized by BRTI. The BRL-BRTI-DBL cooperation involved institutional support, scientific training, joint research programmes, and technology transfer, and forms a basis for the discussion of North-South and South-South collaboration in this paper. As the collaboration matured, DBL researchers began cooperating with their counterparts at BRL in internationally funded research programmes and partnerships based on mutual interests and responsibilities. Several research projects were formulated under co-principal investigators from the two institutions and later extended to other European and US institutions. An impressive outturn (18 PhDs) of postgraduate students undertaking field-based PhD work was accomplished from 1990 to 2001. As the socioeconomic situation in Zimbabwe deteriorated from 1999, significant attrition of senior scientists began to affect some of BRL's core functions in support of the Ministry of Health's programmes. In solidarity with BRL, DBL and BRTI jointly implemented a management-strengthening project to reduce deterioration of research productivity by retaining mid-level research managers. BRTI, able to respond rapidly to research needs in the Southern Africa Development Community (SADC), is not in competition with national research institutions and universities. An advisory committee of SADC stakeholders sets its priorities. The framework for South-South cooperation is research training to facilitate national scientists to attract resources from local and international funding agencies. It has established a National Institutes of Health-accredited ethical review board that provides ethical assurance for BRTI and non-BRTI-administered projects. Over the last eight years, BRTI has established regional and international legitimacy, and many funding agencies accept the role of the organization in 'Third Country Training for South-South Cooperation'. The article concludes by identifying essential conditions for sustaining research capability at BRL and similar institutions in developing countries. In rolling out a new ethos for research, great expectation is placed on the success of the New Partnership for Africa Development.
Communicable Disease Control↗
Population growth and a sustainable environment. The Machakos story.
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Africa↗
Looking for a regenerative approach to sustainability.
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Behavior↗
Spatiotemporal dynamics of CREB phosphorylation: transient versus sustained phosphorylation in the developing striatum.
The cAMP response element-binding protein (CREB) is a plasticity-associated transcription factor that can potentially integrate cAMP and calcium signals at the gene activation level. We tested for convergent Ser-133 phosphorylation of CREB via dopamine D1/D5 receptors and L-type calcium channels in organotypic cultures of neonatal striatum. We found such convergence only transiently. Sustained CREB phosphorylation by D1/D5 receptor and L-type channel agonists was targeted to opposite (striosome and matrix) cellular phenotypes. Subsequent expression of the CRE-containing gene, c-fos, matched the divergent patterns of sustained CREB phosphorylation, and both divergent patterns could be switched by inhibition of phosphatases, including calcineurin. Control of the duration of CREB phosphorylation may be a critical regulator of CRE-mediated gene expression by dopamine and calcium.
Animals↗
Epileptiform activity in microcultures containing one excitatory hippocampal neuron.
1. Paroxysmal depolarizing shifts (PDSs) occur during interictal epileptiform activity. Sustained depolarizations are characteristic of ictal activity, and events resembling PDSs also occur during the sustained depolarizations. To study these elements of epileptiform activity in a simpler context, I used the in vitro chronic-excitatory-block model of epilepsy of Furshpan and Potter and the microculture technique of Segal and Furshpan. 2. Intracellular recordings were made from 93 single-neuron microcultures. Forty of these solitary neurons were excitatory, their action potentials were replaced by PDS-like events or sustained depolarizations as kynurenate was removed from the perfusion solution. PDS-like events were similar to PDSs in intact cortex, mass cultures, and microcultures with more than one neuron. Small voltage fluctuations were also seen in solitary excitatory neurons in the absence of recorded action potentials. Sustained depolarizations developed in 5 of the 40 excitatory neurons. Forty-eight of the 93 solitary neurons were inhibitory, with bicuculline-sensitive hyperpolarizations after the action potential (ascribable to gamma-aminobutyric acid-A autapses). None of the solitary inhibitory neurons displayed sustained depolarizations. Five of the 93 neurons were insensitive to both kynurenate and bicuculline and were not placed in either the excitatory or the inhibitory category. 3. Both N-methyl-D-aspartate (NMDA) and non-NMDA glutamate receptors contributed to the PDS-like events and sustained depolarizations. Only a non-NMDA glutamate receptor component was evident for the small voltage fluctuations. 4. Intracellular recordings were also made from two-neuron microcultures, each containing one excitatory neuron and one inhibitory neuron. Sustained depolarizations developed in five microcultures, in each case only in the excitatory neuron.
Animals↗
Small interfering RNA effectively inhibits protein expression and negative strand RNA synthesis from a full-length hepatitis C virus clone.
Hepatitis C virus (HCV) infection is usually treated with the combination of interferon and ribavirin, but only a small fraction of patients develop a sustained remission. There is need for the development of specific molecular approaches for the treatment of chronic HCV infection. We propose that RNA interference is highly effective antiviral strategy that offers great potential for the treatment of HCV infection. Three plasmid constructs expressing small interfering RNAs (siRNAs) targeted to sequences encoding the structural gene (E2) and non-structural genes (NS3, NS5B) of HCV1a genome were prepared. Antiviral properties of siRNAs against the HCV1a strain were studied in a transient replication model that involved the use of a transcription plasmid containing the full-length HCV genome and an adenovirus expressing T7 RNA polymerase. We found that siRNAs targeted to the E2, NS3 and NS5B regions of the HCV genome efficiently inhibited expression of the HCV core and NS5A protein measured by Western blot analysis and immunocytochemical staining. Intracytoplasmic immunization of siRNAs in HCV-transfected cells efficiently degraded genomic positive strand HCV RNA, as shown by ribonuclease protection assay (RPA). All three siRNAs efficiently inhibited synthesis of replicative negative strand HCV RNA in the transfected cells. A control siRNA plasmid against a Epstein--Barr virus latency gene did not inhibit protein expression and negative strand HCV RNA. These results suggest that RNAi is an effective and alternative approach that can be used to inhibit HCV expression and replication.
Blotting, Western↗
Hot-melt extruded ethylcellulose cylinders containing a HPMC-Gelucire core for sustained drug delivery.
The objective of the study was to develop a sustained release system consisting of a hot-melt extruded ethylcellulose pipe surrounding a drug-containing hydroxypropyl methylcellulose (HPMC)-Gelucire 44/14 core, yielding a monolithic matrix system applicable in the domain of sustained drug release. The influence of HPMC substitution type and viscosity grade was investigated through dissolution testing and erosion studies. All sustained release systems showed a nearly constant drug release profile with only 40% of the drug released after 24 h. To achieve complete drug release after 24 h, the core formulation and the dimensions of the hollow pipe were modified. Changing the composition of the core did not result in the intended zero-order drug release. Shortening the length of the ethylcellulose cylinder accelerated drug release, while modifying the diameter did not affect the drug release rate. The drug dissolution profile and the release mechanism were independent of drug solubility. Increasing the drug loading caused a small increase of the drug release rate, but did not alter the release mechanism.
Cellulose↗
A 16-year follow-up study on bancroftian filariasis in three communities of north-eastern Tanzania.
The results of a 16-year, parasitological and clinical, follow-up study on bancroftian filariasis in three villages in north-eastern Tanzania are reported and analysed with respect to the long-term development of microfilaraemia and disease. The study revealed an extraordinary static situation, both at the community level and at the individual level. No significant differences were observed in any of the three villages, with respect to total or age-specific prevalences of microfilaraemia, hydrocele in males aged > or = 20 years or leg elephantiasis in all subjects aged > or = 20 years, when the results from 1975 were compared with those from 1991. Overall, 542 of the subjects (37.2% of the total) examined in 1975 were re-identified and re-examined in 1991. Of those microfilaraeic in 1975, 81.9% were also microfilaraemic in 1991. Similarly, 81.3% of those amicrofilaraemic in 1975 were also amicrofilaraemic in 1991. Thus, most subjects had the same microfilarial (mf) status at both surveys. The low mf loss rate indicates that re-infection of microfilaraemic individuals commonly takes place, and results in repeated sequences of microfilaraemia in the same individuals. The rate of gain of microfilaraemia was independent of age, thus indicating no age-related change in the examined population's susceptibility to develop or sustain microfilaraemia. Individual differences in susceptibility to develop mirofilaraemia therefore appear to be innately determined, or to be acquired in pre-natal or early post-natal life. Neither the presence of hydrocele in 1991, nor the development of new cases of hydrocele over the 16-year period were related to the mf status in 1975 or 1991, and no association between microfilaraemia and this chronic clinical manifestation was observed. The association between leg elephantiasis and mf status could not be analysed because of the small sample size.
Adolescent↗
Floods in a changing climate: a review.
This paper begins with an analysis of flooding as a natural disaster for which the solutions to the environmental, social and economic problems are essentially those of identifying and overcoming hazards and vulnerability, reducing risk and damaging consequences. Long-term solutions to flooding problems, especially in a changing climate, should be sought in the wider context of developing more sustainable social organization, economics and technology. Then, developments are described of how scientific understanding, supported by practical modelling, is leading to predictions of how human-induced changes to climatic and geological conditions are likely to influence flooding over at least the next 300 years, through their influences on evaporation, precipitation, run-off, wind storm and sea-level rise. Some of the outstanding scientific questions raised by these problems are highlighted, such as the statistical and deterministic prediction of extreme events, the understanding and modelling of mechanisms that operate on varying length- and time-scales, and the complex interactions between biological, ecological and physical problems. Some options for reducing the impact of flooding by new technology include both improved prediction and monitoring with computer models, and remote sensing, flexible and focused warning systems, and permanent and temporary flood-reduction systems.
Climate↗
Sustaining NGOs in the developing world: a perspective from the developing world.
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Asia↗
The relationship between intracellular [Ca(2+)] and Ca(2+) wave characteristics in permeabilised cardiomyocytes from the rabbit.
Spontaneous sarcoplasmic reticulum (SR) Ca(2+) release and propagated intracellular Ca(2+) waves are a consequence of cellular Ca(2+) overload in cardiomyocytes. We examined the relationship between average intracellular [Ca(2+)] and Ca(2+) wave characteristics. The amplitude, time course and propagation velocity of Ca(2+) waves were measured using line-scan confocal imaging of beta-escin-permeabilised cardiomyocytes perfused with 10 microM Fluo-3 or Fluo-5F. Spontaneous Ca(2+) waves were evident at cellular [Ca(2+)] > 200 nM. Peak [Ca(2+)] during a wave was 2.0-2.2 microM; the minimum [Ca(2+)] between waves was 120-160 nM; wave frequency was approximately 0.1 Hz. Raising mean cellular [Ca(2+)] caused increases in all three parameters, particularly Ca(2+) wave frequency. Increases in the rate of SR Ca(2+) release and Ca(2+) uptake were observed at higher cellular [Ca(2+)], indicating calcium-sensitive regulation of these processes. At extracellular [Ca(2+)] > 2 microM, the mean [Ca(2+)] inside the permeabilised cell did not increase above 2 microM. This extracellular-intracellular Ca(2+) gradient could be maintained for periods of up to 5 min before the cardiomyocyte developed a sustained and irreversible hypercontraction. Inclusion of mitochondrial inhibitors (2 microM carbonyl cyanide m-chlorophenylhydrazone and 2 microM oligomycin) while perfusing with > 2 microM Ca(2+) abolished the extracellular-intracellular Ca(2+) gradient through the generation of Ca(2+) waves with a higher peak [Ca(2+)] compared to control conditions. Under these conditions, cardiomyocytes rapidly (< 2 min) developed a sustained and irreversible contraction. These results suggest that mitochondrial Ca(2+) uptake acts to delay an increase in [Ca(2+)] by blunting the peak of the Ca(2+) wave.
Animals↗
Terminating life-sustaining treatment--recent US developments.
This paper reviews some recent litigation in the United States which addresses the difficult question of withdrawing food and hydration from both competent and incompetent patients. Whilst the decisions in question have manifested a trend towards favouring patient autonomy, they also indicate an underlying tension between doctors, health care facilities and their dying patients which is not yet close to resolution. The author suggests that the courts in the United States are likely to remain, for the foreseeable future, the final arbiters in that country of disputes relating to the termination of life-sustaining treatment.
Euthanasia↗
Corona radiata density as a non-invasive marker of bovine cumulus-corona-oocyte complexes selected for in vitro embryo production.
The density of the corona radiata as a marker for the quality of cumulus-corona-oocyte complexes (CCOC's) for in vitro embryo production was tested. The CCOC's in which the corona radiata appeared as a dark rim surrounding the zona pellucida (Group 1) and CCOC's in which the corona had the same density as the rest of the cumulus investment (Group 2) were assessed with respect to nuclear ultrastructure, corona-cumulus expansion and capacity for sustaining embryonic development in vitro. An intermediate Group 3 with characteristics between Groups 1 and 2 was also assessed for in vitro development capacity. The CCOC's in Group 1 were typically meiotically unactivated and presented a nonundulating nuclear envelope. More than half of the CCOC's in Group 2 showed some degree of meiotic activation, and those that were nonactivated displayed "holes" in the nuclear envelope or dilatations of the perinuclear cisterna. The CCOC's in Group 2 were characterized by partial corona-cumulus expansion already at collection. The CCOC's from Groups 1 and 3 sustained embryonic development in vitro at a significantly higher rate than CCOC's from Group 2. It is concluded that CCOC's in which the corona radiata has the same density as the rest of the cumulus investment are less competent candidates for in vitro embryo production.
Journal Article↗