Natural might not be healthier.
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Food Preferences↗
Biomedical subjects
B Dixon
Publications and source records attributed to B Dixon.
Activation of the kallikrein-kinin system by cardiopulmonary bypass in humans.
We used cardiopulmonary bypass (CPB) as a model of activation of the contact system and investigated the involvement of the plasma and tissue kallikrein-kinin systems (KKS) in this process. Circulating levels of bradykinin and kallidin and their metabolites, plasma and tissue kallikrein, low and high molecular weight kininogen, and kallistatin were measured before, during, and 1, 4, and 10 h after CPB in subjects undergoing cardiac surgery. Bradykinin peptide levels increased 10- to 20-fold during the first 10 min, returned toward basal levels by 70 min of CPB, and remained 1.2- to 2.5-fold elevated after CPB. Kallidin peptide levels showed little change during CPB, but they were elevated 1.7- to 5.2-fold after CPB. There were reductions of 80 and 60% in plasma and tissue kallikrein levels, respectively, during the first minute of CPB. Kininogen and kallistatin levels were unchanged. Angiotensin-converting enzyme inhibition did not amplify the increase in bradykinin levels during CPB. Aprotinin administration prevented activation of the KKS. The changes in circulating kinin and kallikrein levels indicate activation of both the plasma and tissue KKS during activation of the contact system by CPB.
Angiotensin I↗
Hindsight blinkers Britain's mad cow disease response.
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Animals↗
Meningitis vaccination programme prompts needless scare.
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Humans↗
Coliform confusion.
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Escherichia coli O157↗
An injection of good sense
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Journal Article↗
Range expansion of the tick Amblyomma triguttatum triguttatum, an australian vector of Q fever.
The tick Amblyomma triguttatum triguttatum has previously been reported from Western Australia, Queensland and New South Wales. A viable population of this species, including all developmental stages, has now been discovered on the southern end of Yorke Peninsula, South Australia. Species determination was carried out morphologically and using 18S and 16S rRNA. The data for 16S rRNA are the first published for this species. Amblyomma t. triguttatum is significant through its involvement in the natural, Australian cycle of Coxiella burnetti, the pathogen causing Q fever. The environment of Yorke Peninsula contains all of the components required for a natural Q fever cycle and three cases of this disease have been reported from this area since 1995. These findings reinforce the need to put in place effective mechanisms to monitor parasite distributions at a time of large scale global change.
Animals↗
Angiotensin III depressor action in the conscious rabbit is blocked by losartan but not PD 123319.
Vasodilator and vasodepressor properties of angiotensins have been reported, and mediation by prostaglandins or nitric oxide has been proposed. Other studies indicate that angiotensin AT(2) receptors might mediate a depressor action, and the present study was designed to delineate and explore this possibility in a conscious rabbit model. Large intravenous boluses of angiotensin III (15 nmol/kg) produced a predictable pressor peak (82+/-4 mm Hg) followed by a depressor phase (20+/-3 mm Hg), whereas equipressor doses of angiotensin II were less effective at producing depressor responses. Angiotensin-(1-7) did not exert a depressor action, and the reduced potency of angiotensin IV (relative to angiotensin III) was similar for both the pressor and depressor phases ( approximately 100-fold). It is clear that specific angiotensin IV or angiotensin-(1-7) receptors do not mediate depressor effects in this model. The AT(1) antagonist losartan (1 mg/kg) blocked both the pressor and depressor components of the angiotensin III response, whereas the AT(2) antagonist PD 123319 (35 mg/kg) had no effect on either element of the response. The data obtained with the angiotensin receptor subtype-selective compounds, losartan and PD 123319, suggest that the depressor action is an AT(1)-mediated effect and give no indication that AT(2) receptors could be involved. Paradoxically, the greater potency of angiotensin III as a vasodepressor belies the conclusion that the response is AT(1)-mediated, because AT(1) receptors have a greater affinity for angiotensin II versus angiotensin III.
Angiotensin I↗
Mitochondrial DNA depletion in children.
The first girl of an unrelated couple was noted to have failure to thrive since age 3 months, generalized hypotonia and weakness, hepatomegaly, hypoglycemia, and lactic acidosis at 4 months. She was found to have severe mitochondrial DNA (mtDNA) depletion and respiratory chain complex IV deficiency in both skeletal muscle and liver but without other common mtDNA mutations. Her younger brother developed vomiting at age 3 weeks and was diagnosed as having pyloric stenosis. His skeletal muscle and liver also showed severe mtDNA depletion. He developed generalized weakness and hypotonia, hepatomegaly, and lactic acidosis at age 3 months. Both siblings died of hepatic failure and hemorrhagic complication before 6 months of age. The brother also had chemical pancreatitis, which had not been reported before in mtDNA depletion in children. Severe mtDNA depletion may present with nonspecific symptoms such as vomiting, failure to thrive, and developmental delay; multiorgan involvement such as hepatomegaly, pancreatitis, and myopathy occurs later. Mitochondrial DNA depletion should be considered in the differential diagnosis in children with developmental delay or failure to thrive of unknown etiology.
DNA Fragmentation↗
Yeast as factory and factotum.
After centuries of vigorous activity in making fine wines, beers and breads, Saccharomyces cerevisiae is now acquiring a rich new portfolio of skills, bestowed by genetic manipulation. As shown in a recent shop-window of research supported by the European Commission, yeasts will soon be benefiting industries as diverse as fish farming, pharmaceuticals and laundering.
Alcoholic Beverages↗
GM frenzy: a lesson in communication.
Hysteria rather than rationality has characterised the debate over genetically modified foods, which erupted in Britain in 1998 and has since spread to other countries. This episode holds wider lessons for biologists, politicians and all concerned with the prudent assessment and application of novel technology.
Allergens↗
Synthesis and structure activity relationships of novel small molecule cathepsin D inhibitors.
Cathepsin D, a lysosomal aspartyl protease, has been implicated in the pathology of Alzheimer's disease as well as breast and ovarian cancer. A weakly active cathepsin D inhibitor was identified by high throughput screening. Subsequent optimization led to the discovery of a new class of small molecule inhibitors of this enzyme, culminating with the sulfonamide 13 (IC50 = 250 nM).
Cathepsin D↗
When a butterfly flaps its wingsellipsis
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Journal Article↗
The origins of AIDS.
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Acquired Immunodeficiency Syndrome↗