bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of creatine loading and depletion on rat skeletal muscle contraction
Authors: Gagnon M , Maguire M , MacDermott M , Bradford A 
Published: March 2003

Summary1. In humans, the effects of dietary creatine supplementation are controversial, with some studies showing increased muscle force and fatigue resistance and others reporting no effect on exercise performance. Little is known about the effects of creatine on muscle contractile properties.2. Rats were fed a standard diet, creatine for 10 days or β‐guanidinopropionate, which depletes muscle creatine, for 7 days. Contractile properties were measured in isolated extensor digitorum longus and sternohyoid muscle as representative limb and upper airway dilator muscles, respectively.3. Creatine had no effect on specific twitch and tetanic tension, contractile kinetics, twitch/tetanus tension ratio, the tension–frequency relationship or fatigue in both muscles. β‐Guanidinopropionate had no effect on the twitch and tetanic tension, contractile kinetics, twitch/tetanus tension ratio or tension–frequency relationship, but significantly increased (P < 0.05, anova) fatigue in both muscles.4. Therefore, although creatine depletion increases fatigue, creatine loading has no effects on extensor digitorum longus and sternohyoid muscle contractile properties.
Antiplatelet effects of policosanol (20 and 40 mg/day) in healthy volunteers and dyslipidaemic patients
Authors: Arruzazabala María Lourdes , Molina Vivian , Mas Rosa , Fernández Lilia , Carbajal Daisy , Valdés Suria , Castaño Gladys 
Published: March 2003

Summary1. The present study was undertaken to compare the effects of a higher dose of policosanol, a cholesterol‐lowering drug, (40 mg/day) with the effects of 20 mg/day policosanol on platelet aggregation in healthy volunteers and type II hypercholesterolaemic patients.2. Study subjects were randomized to receive, under double‐blind conditions, placebo or policosanol (20 or 40 mg/day) for 30 days once a day. Blood sampling was performed at baseline and after 30 days on therapy.3. Platelet aggregation was induced with three aggregating agents: arachidonic acid (AA), collagen and low doses of ADP.4. Policosanol (20 and 40 mg/day) moderately yet significantly reduced platelet aggregation, but no differences were observed in the effects produced by either dose of policosanol. In healthy volunteers, policosanol at 20 and 40 mg/day inhibited aggregation induced by 2 mmol/L AA (28.2 and 24.9%, respectively), 1 µg/mL collagen (21.1 and 20.2%) and 1µmol/L ADP (30.9 and 29.1%). Changes that occurred following the adminstration of placebo were not significant, although an upward trend for collagen‐ and ADP‐induced aggregation occurred in normal and hypercholesterolaemic subjects, respectively, thus partially masking the effects of policosanol on these responses.5. The antiplatelet effects of policosanol at 20 and 40 mg/day in hypercholesterolaemic patients were also similar, so that both doses inhibited aggregation induced by 1.5 mmol/L AA (20.1 and 33.0%, respectively), 0.5 µg/mL collagen (22.7 and 21.1%) and1 µmol/L ADP (40.5 and 34.7%).6. In addition, after 30 days of therapy, 20 and 40 mg/day policosanol significantly (P < 0.01) reduced low‐density lipoprotein–cholesterol (15.9 and 17.0%, respectively) and total cholesterol (12.4 and 12.3%, respectively; P < 0.05), yet increased high‐density lipoprotein–cholesterol values by 5% in both groups (P < 0.05).7. Triglycerides were decreased compared with baseline, but not with respect to the placebo.8. We conclude that the antiplatelet effects induced by 40 mg/day policosanol administered for 30 days to healthy volunteers and to hypercholesterolaemic patients were similar to the effects induced by 20 mg/day policosanol. Thus, no enhancement of the response was achieved with the use of a higher dose of policosanol in study patients.
Effects of Ginkgo biloba extract (EGb 761) on cerebral thrombosis and blood pressure in stroke‐prone spontaneously hypertensive rats
Authors: Sasaki Yasuto , Noguchi Takanori , Yamamoto Etsuko , Giddings John C , Ikeda Katsumi , Yamori Yukio , Yamamoto Junichiro 
Published: March 2003

Summary1. An extract of Ginkgo biloba (EGb 761) has been reported to alleviate cerebrovascular problems. In the present study, we investigated the antithrombotic effects of EGb 761 in cerebral blood vessels of stroke‐prone spontaneously hypertensive rats (SHRSP/Izm).2. In the present study, EGb 761 was administered orally to SHRSP/Izm at 60 and 120 mg/kg each day for 3 weeks from the age of 7 weeks. The age‐related increase in blood pressure observed in SHRSP was suppressed significantly by EGb 761 at both doses 3 weeks after treatment.3. Thrombotic potential was assessed in vivo using a He‐Ne laser‐induced thrombosis model and was significantly suppressed by EGb 761.4. The anti‐oxidant effects of EGb 761 were determined by measurement of urinary 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG). At 120 mg/kg, EGb 761 decreased 8‐OHdG significantly compared with control animals.5. Urinary nitrite/nitrate, nitric oxide (NO) metabolites, were increased significantly after administration of EGb 761. Expression of endothelial NO synthase (eNOS) mRNA was measured using a real‐time quantitative reverse transcription–polymerase chain reaction method. The expression of eNOS mRNA in the EGb 761 group (120 mg/kg) was significantly higher than in the control group.6. The results indicate that EGb 761 decreases blood pressure and mediates strong antithrombotic and anti‐oxidant effects in SHRSP. These pharmacological activities may contribute to the beneficial properties of EGb 761 observed in clinical practice.
Evolution of drug metabolism: Hitchhiking the technology bandwagon
Authors: Miners John O 
Published: March 2003

Summary1. The application of a range of established and emerging technologies and experimental approaches has allowed investigation of cytochrome P450 (CYP) and uridine diphosphate‐glucuronosyltransferase (UGT) at the functional, structural and molecular levels to address questions of therapeutic relevance, particularly the wide interindividual variability in metabolic clearance characteristic of drugs and chemicals metabolized by these enzymes.2. Studies in vivo initially identified the various factors that contribute to interindividual variability. Subsequently, human liver microsomal kinetic approaches, together with the cloning and functional characterization of recombinant CYP and UGT isoforms, led to the development of in vitro strategies that allowed the qualitative prediction of those factors likely to alter the metabolic clearance of a given compound in vivo. More recently, computer (in silico) modelling has been used to complement the laboratory based procedures.3. The application of molecular biological approaches additionally allowed identification of the mutations responsible for CYP and UGT genetic polymorphism and, in some instances, the domains and individual amino acids that confer isoform substrate and inhibitor selectivities. Homology models, developed using X‐ray crystallographic data as the template, potentially enable prediction of the functional consequences of altered CYP structure.4. The rapid advances occurring in genomics, proteomics, gene expression analysis and computer modelling will allow further unravelling of the complexities of drug metabolism and improved prospects for the individualization of drug therapy.
Changes in mean arterial pressure predict degranulation of renomedullary interstitial cells
Authors: Maric Christine , Harris Peter J , Alcorn Daine 
Published: March 2003

Summary1. Renomedullary interstitial cells (RMIC) are characterized by numerous intracellular granules thought to contain renal medullary antihypertensive substances. However, the nature of the trigger for RMIC degranulation remains to be elucidated. The present study examines the effects of acute alterations in mean arterial pressure (MAP) and medullary blood flow (MBF) on RMIC granulation.2. Basal MAP and MBF in anaesthetized Sprague‐Dawley rats (n = 4/group) were altered by intravenous infusions of vasoactive agents, including angiotensin II alone or with a nitric oxide (NO) synthase inhibitor (Nω‐nitro‐l‐arginine) or NO donor (sodium nitroprusside), noradrenaline and by carotid artery clamping. Following these treatments, kidneys were examined by electron microscopy and the absolute volume of granules in the renal medulla was calculated using unbiased stereological methods.3. Acute increases in MAP, regardless of the treatment causing the increase, were associated with a reduction in the absolute volume of granules in the range of 42–67%. Regression analysis revealed that only increases in MAP, but not MBF, strongly predict RMIC degranulation.4. Despite previous reports that changes in MBF activate renomedullary antihypertensive activity, we conclude that the change in MAP is an important determinant of the activity of the blood pressure‐lowering mechanism of the renal medulla, with the assumption that the medullary lipids mediate the antihypertensive property of the renal medulla.
βFTZ‐F1 dependent and independent activation of Edg78E, a pupal cuticle gene, during the early metamorphic period in Drosophila melanogaster
Authors: Kawasaki Haruhisa , Hirose Susumu , Ueda Hitoshi 
Published: March 2003

Insect metamorphosis is a developmentally important event for formation of adult structures from larval imaginal cells, and it is controlled by the ecdysteroid hormone. At the onset of metamorphosis, both the cuticle gene Edg78E and the transcription factor βFTZ‐F1 are expressed during the mid‐ to late prepupal period after a large ecdysteroid pulse. Edg78E mRNA is inducible by premature expression of βFTZ‐F1 and the Edg78E expression level is reduced in an ftz‐f1 mutant. Using a transgenic fly reporter assay, a 1.2 kb promoter region of the Edg78E gene has been identified, which was sufficient for appropriate temporally and spatially specific expression of the reporter gene LacZ. Within the promoter region, two βFTZ‐F1 binding sites are present and disruption of these sites reduced the expression level of the reporter gene. LacZ expression levels were dramatically reduced in the head and thorax regions but not affected in the abdominal region, suggesting that βFTZ‐F1 is required for high‐level Edg78E expression specifically in the head and thorax regions. The findings suggest that βFTZ‐F1 is a regulator for temporal gene expression at the onset of metamorphosis, and that complex mechanisms regulate the temporal and spatial regulation of gene expression during metamorphosis.
Knockdown of connexin43‐mediated regulation of the zone of polarizing activity in the developing chick limb leads to digit truncation
Authors: Law Lee Yong , Lin Jun Sheng , Becker David L. , Green Colin R. 
Published: March 2003

In the developing chick wing, the use of antisense oligodeoxynucleotides to transiently knock down the expression of the gap junction protein, connexin43 (Cx43), results in limb patterning defects, including deletion of the anterior digits. To understand more about how such defects arise, the effects of transient Cx43 knockdown on the expression patterns of several genes known to play pivotal roles in limb formation were examined. Sonic hedgehog (Shh), which is normally expressed in the zone of polarizing activity (ZPA) and is required to maintain both the ZPA and the apical ectodermal ridge (AER), was found to be downregulated in treated limbs within 30 h. Bone morphogenetic protein‐2 (Bmp‐2), a gene downstream of Shh, was similarly downregulated. Fibroblast growth factor‐8 expression, however, was unaltered 30 h after treatment but was greatly reduced at 48 h post‐treatment, when the AER begins to regress. Expressions of Bmp‐4 and Muscle segment homeobox‐like gene (Msx‐1) were not affected at any of the time points examined. Cx43 expression is therefore involved in some, but not all patterning cascades, and appears to play a role in the regulation of ZPA activity.
Initial verification of the resistance management strategy for Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) in Australia
Authors: Herron GA , Cook DF 
Published: March 2003

AbstractShortly after the initial detection of western flower thrips (WFT), Frankiniella

occidentalis (Pergande), in Australia during 1993 a resistance management strategy based on the alternation of chemical groups was implemented. This study aimed to verify this strategy by field testing α‐cypermethrin against WFT with and without chemical alternation. Up to 114 times α‐cypermethrin resistance (at LC50) was detected and resistance increased with and without chemical alternation; however, chemical alternation did significantly reduce numbers of thrips compared with a nonalternation strategy. Resistance has the potential to undermine the sustainable use of those chemicals to which there is no current detectable resistance. Consequently, chemicals with a high frequency and level of resistance against WFT need to be identified through monitoring and quickly eliminated from WFT chemical control recommendations.
Initiation of thrombolytic therapy for patients with acute myocardial infarction by emergency physicians: The Hong Kong experience
Authors: Ming Tang Ho , Lung Lau Fei , Kwong Chan Wai 
Published: March 2003

Abstract Objectives: To compare door‐to‐needle time and complications for eligible acute myocardial infarction patients receiving thrombolytic therapy in the emergency department and in the coronary care unit. Methods: A prospective study was performed involving all patients with acute myocardial infarction who received thrombolytic therapy either in the emergency department or the coronary care unit during the period January 1995 to March 1996. Patients’ time interval between registration in ED and receiving thrombolytic therapy (door‐to‐needle time) was the main audit parameter. Other emergency department information collected included inappropriate administration of thrombolytic therapy and the occurrence and management of complications of thrombolytic therapy. Results: In the United Christian Hospital, Hong Kong, 148 patients with acute myocardial infarction received thrombolysis. Sixty‐eight cases (group A) received thrombolysis in the emergency department and 80 cases underwent thrombolysis in the coronary care unit. The 80 cases in the coronary care unit included 47 cases (group B) whose diagnosis of acute myocardial infarction and eligibility for thrombolysis were established in the emergency department, and 33 cases (group C) in which there were difficulties in diagnosis or exclusion of contraindications for thrombolysis. The mean door‐to‐needle times were 31.3 min in group A (95% CI, 27.6–35.1), 54 min in group B (95% CI, 47.8–60.2) and 171.8 min in group C (95% CI, 121.8–211.8). Inappropriate use of thrombolysis in the emergency department occurred in 2.9% of all cases. The most common complication of thrombolysis in the emergency department was hypotension (4.4%). All cases were successfully managed in the emergency department. There was one case of anaphylaxis during streptokinase infusion that required resuscitation in the emergency department. There were no deaths of patients receiving thrombolysis in the emergency department. Conclusion The initial experience of a regional hospital in Hong Kong supports the view that initiation of thrombolytic therapy in the emergency department can achieve a more favourable door‐to‐needle time without compromising the care of acute myocardial infarction patients.
Isolated pulmonary oedema associated with SCUBA diving
Authors: Grindlay Joanne , Mitchell Simon 
Published: March 2003

AbstractPulmonary oedema may be a presenting feature of the classical diving illnesses decompression illness and barotrauma, but it may also present as an isolated phenomenon. Possible causes include: salt water aspiration syndrome or near drowning (sometimes associated with faulty apparatus); and cold, immersion and exercise‐induced pulmonary oedema. The pathophysiology may involve peripheral vasoconstriction; changes in preload, afterload and circulating fluid volume; and pulmonary capillary fragility. A case that presented to Auckland Hospital is discussed, together with a review of the literature. In this case, treatment with continuous positive airway pressure ventilation proved highly effective. Guidelines for the use of continuous positive airway pressure ventilation in diving‐related accidents are presented.
Urinalysis and the plain abdominal radiograph in the diagnosis of ureteric colic
Authors: Shield Andrew C , Chu Kevin , Brown Anthony FT 
Published: March 2003

Abstract Objectives: 1. To investigate the diagnostic accuracy of urinalysis and the plain abdominal radiograph in predicting positive intravenous pyelography for patients with a history and examination suggestive of ureteric colic. 2. To examine the disposition of patients presenting to the emergency department with ureteric colic. Methods: A retrospective cohort study set in a tertiary referral hospital emergency department over a 12‐month period was conducted. Three hundred and eighteen patients who presented with a provisional diagnosis of ureteric colic and had intravenous pyelography were identified from radiology department logs and emergency department discharge International Classification of Disease‐9 codes. Results: Three hundred and eighteen patients were identified. Sixty‐nine per cent had positive intravenous pyelography. Sensitivity and specificity of: urinalysis were 93% and 41%; abdominal X‐ray, 57% and 83%; and urinalysis plus abdominal X‐ray, 99% and 36%, respectively. Seventy‐seven per cent were admitted to the emergency department observation ward. Twenty‐seven per cent were subsequently admitted under the hospital’s urology service. Conclusions: Sex, haematuria and the presence of a calculus on abdominal X‐ray were all significant predictors of positive intravenous pyelography. Haematuria was sensitive but not specific for positive intravenous pyelography. The addition of the abdominal X‐ray marginally improves the diagnostic accuracy.
Status of emergency department ultrasound
Authors: Fulde Gordian 
Published: March 2003

Abstract Objective: To determine present attitudes to and usage of ultrasound in Australasian emergency medicine. Methods: A questionnaire was devised, field tested and sent, with Australasian College for Emergency Medicine permission, for anonymous completion by the director of emergency medicine training of each emergency department in Australia and New Zealand accredited for advanced training. Results: The overall response rate was 84% (66/79). The data were tabulated and cross‐tabulated comparing major trauma centres, base hospitals, urban hospitals and teaching hospitals. In hours, X‐ray department ultrasound was readily available, but bedside ultrasound was much less available both in and out of hours. There were marked variations in opinion as to whether bedside ultrasound was essential in clinical conditions such as trauma, abdominal or kidney pain. Computed tomography was always preferred to ultrasound. While there was little teaching of either the theoretical or practical aspects of ultrasound to emergency medicine trainees, 75% of respondents believed that ultrasound should not be undertaken only by full‐time ultrasonographers. Conclusions: The survey clearly demonstrated that while bedside or urgent ultrasound is not generally readily available, especially out of hours, the modality is considered to be important by the majority of respondents, and does not require full‐time radiographers. It is clear that formal teaching of ultrasound to trainees is infrequent.
Why do people still die from brown‐snake bites?
Authors: White Julian 
Published: March 2003

AbstractBrown snakes are the leading cause of snakebites and snakebite fatalities in Australia and the incidence may be rising. Most fatalities are the result of early events after the bite, often a general or cardiac collapse. Lack of appropriate first aid is a common finding. It is probable that an early thrombotic effect of venom procoagulants, prior to defibrination, is responsible for the cardiac collapse in most of these cases. CSL brown‐snake antivenom, while not perfect, is usually effective if given in sufficient quantity, but cannot reverse established vital‐organ damage. Increased public education about the danger of snakebite and correct first aid may reduce the death toll, and improved professional continuing education on snakebite is advisable but, ultimately, some brown‐snake bite deaths are probably inevitable, despite optimum medical care.
Tiger‐snake antivenom for suspected small‐eyed snake envenomation
Authors: Ivermee Peter , Desjardines Jude , McEwan Steve 
Published: March 2003

AbstractDespite its relative frequency and widespread distribution throughout eastern Australia, bites by the nocturnal eastern small‐eyed snake, Cryptophis nigrescens, have seldom been recorded. There is no standard laboratory test or proven antidote for its venom, which is capable of causing life‐threatening myolysis in humans. A 39‐year‐old man presenting to hospital with acute abdominal and limb muscle pains, was noted to have a pair of puncture wounds on his leg. No venom was detected in the urine with the Commonwealth Serum Laboratories’ Venom Detection Kit. The only blood abnormality was a grossly elevated creatine kinase at 48 000 IU/L. A presumptive diagnosis of Cryptophis nigrescens envenomation was made and the patient treated with tiger‐snake antivenom (3000 U). Creatine kinase levels started to fall almost immediately and the patient made a full recovery. We believe this is the first time tiger‐snake antivenom has been used specifically for suspected Cryptophis nigrescens envenomation.
Ipecac for slow‐release potassium poisoning: Pariah or phoenix?
Authors: Geluk Michael , Braitberg George 
Published: March 2003

AbstractThe ingestion of a large amount of slow‐release potassium tablets presents the clinician with the problem of how best to decontaminate the gastrointestinal tract of such a patient. Oral potassium preparations are not adsorbed by charcoal and therefore an alternative must be used. The choice is between gastric emptying via emesis or surgery and whole‐bowel irrigation. At present, the scientific literature does not answer adequately the question of which one offers the best risk–benefit profile. In recent years, the use of ipecac in the emergency department has been discouraged. We present a case of a large ingestion of Slow K tablets (Novartis Pharmaceuticals, North Ryde, NSW, Australia) and discussion of the role of ipecac in the decontamination of similar cases. The question is asked whether ipecac should be considered as the initial method of gastric emptying in this specific circumstance before resorting to surgery or whole‐bowel irrigation.
Treatment of cyanide poisoning in Australasia
Authors: Braitberg George , Vanderpyl Marjory Mj 
Published: March 2003

AbstractThere is controversy about the most effective agent for cyanide poisoning. While dicobalt edetate has been recommended in Australia, hydroxocobalamin has been preferred in Europe. There are no comparative trials of these agents on which to base recommendations. However, a considerable volume of animal work and uncontrolled trials in humans suggest that hydroxocobalamin is safer and at least as effective. Thiosulphate appears to enhance the effect of hydroxocobalamin. The authors recommend that for patients with cyanide poisoning from smoke inhalation, significant self‐poisoning with cyanide or where there is strong clinical suspicion that cyanide poisoning is present, hydroxocobalamin should be given in a dose of 5–15 g over 30 min, or faster if necessary, accompanied by sodium thiosulphate 12.5 g over 10–20 min.