Search Results - (Author, Cooperation:M. Irwin)

2018-04-26

American Chemical Society (ACS)

0006-2960

1520-4995

Biology

Chemistry and Pharmacology

2014-04-26

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; *Endangered Species ; *Extinction, Biological ; *Lemur ; Male

2014-02-22

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; *Endangered Species ; *Extinction, Biological ; *Lemur ; Madagascar ; Male ; Risk

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Radio-autographic techniques have been applied to the study of three hyperplastic human epidermal diseases; psoriasis, seborrhoeic keratoses and Bowen's disease. In each, a different alteration of nucleic acid and protein synthesis has been found when the abnormal tissue is compared to clinically normal contiguous skin. Psoriasis was characterized by stimulation of DNA, RNA and protein synthesis, while in mature seborrhoeic keratoses DNA synthesis was decreased at the same time as RNA and protein synthesis were increased. In Bowen's disease DNA and protein synthesis were enhanced, but the number of cells involved in RNA synthesis was decreased.Similar methods have been applied to psoriatic epidermis during treatment with vitamin A acid ointment. The medication resulted in inhibiton of DNA synthesis at a time when RNA and protein synthesis were enhanced.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Sodium acetate and sulphuric acid extracts of human epidermis can each be separated by chromatographic techniques into three or more fractions with ribonuclease activity. Eight of these fractions were compared with respect to molecular weight, pH activity profile, polyribonucleotide hydrolysis, and activity in the presence of low levels of spermidine. Sodium acetate and sulphuric acid extracts were also prepared from callus and from psoriatic lesions and compared with extracts from normal epidermis for their response to exogenous spermidine.All eight human epidermal ribonuclease fractions studied had an apparent molecular weight of 15,000 daltons. Seven of the ribonuclease fractions were optimally active at alkaline pHs (pH 7.3–7.6 in sodium phosphate and pH 81.in Tris-HCl) while the eighth ribonuclease was most active at pH 5.6 in a citrate-phosphate buffer. All enzymes hydrolyzed polycytidylic acid and five also hydrolyzed polyuridylic add. None hydrolyzed polyadenylic acid. Seven of the eight ribonucleases studied exhibited greater activity in the presence of added spermidine. The extracts from psoriatic scales showed markedly elevated ribonuclease levels which could not be raised further by the addition of spermidine.

Electronic Resource

1468-0270

Blackwell Publishing Journal Backfiles 1879-2005

Economics

Electronic Resource

1468-0270

Blackwell Publishing Journal Backfiles 1879-2005

Economics

Innovation is the key to rising living standards; competition is the key to a rapid rate of innovation.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Characterization of amorphous SiO2 surfaces after biasing pretreatments, which induce nucleation of diamond, has been carried out using x-ray photoelectron spectroscopy and Raman spectroscopy. A mixture of silicon carbide, silicon oxycarbide, and diamond are formed upon exposure of biased SiO2 surfaces to a CH4+H2 plasma used for diamond deposition. It is concluded that nucleation of diamond on amorphous SiO2 surfaces is promoted by formation of a SiC surface layer. Textured diamond films have been fabricated on bulk SiO2 substrates using biasing pretreatments to induce diamond nucleation. © 1997 American Institute of Physics.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have compared the opioid effects of a patient-demand, target-controlled infusion of alfentanil (n = 10), with patient-controlled bolus administration of morphine (n = 10) following major spinal surgery in Chinese patients aged from 11 to 67 years. The same general anaesthesia regimen was used in all patients. One group of patients were given intra-operative morphine analgesia followed by postoperative intravenous morphine patient-controlled analgesia, while the other group received an intra-operative target-controlled infusion of alfentanil. Following surgery, the alfentanil group were given control of a handset and were able to increase the target alfentanil plasma level in 5ng.ml-1 increments with a 2-min lockout interval. If analgesia was not demanded within a 15-min period, the computer reduced the target concentration by 5ng.ml-1. All patients had continuous pulse oximetry monitoring and hourly recording of pain, sedation, nausea scores and respiratory rate. Patients receiving alfentanil had the target concentration noted hourly and four blood samples taken during the first 24 h for measurement of plasma alfentanil concentrations by high performance liquid chromatography. The alfentanil infusion system was equally effective as an analgesic technique when compared with morphine patient-controlled analgesia. There were no hypoxaemic episodes (oxygen saturation 〈94%), no difference in sedation scores and the incidence of nausea (30%) was the same in both groups. There was a significantly (p 〈 0.001) lower respiratory rate in the alfentanil group compared with patients receiving morphine at, clinically assessed, equianalgesia. The predicted plasma alfentanil concentrations increased rapidly from about 30ng.ml-1 during the first 4 h to around 100ng.ml-1 at the end of the 24-h study period. The precision of the target-controlled infusion system was 75.4% and the mean prediction error (bias) 58.1%, suggesting an underestimation of the measured alfentanil concentrations by the alfentanil infusion system in these Chinese patients.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

A 49-year-old male with neurofibromatosis type II was scheduled for posterior fossa craniotomy and excision of a right acoustic neuroma and placement of an auditory brainstem implant in the sitting position. Intra-operatively, the patient was monitored with transoesophageal echocardiography which detected two major episodes of venous air embolism. Despite immediate treatment the patient's gas exchange progressively worsened during surgery and a chest X-ray showed extensive bilateral pulmonary infiltrates. The patient developed acute respiratory distress syndrome and required inotropic support in the intensive care unit. Although transoesophageal echocardiography allowed rapid detection of venous air embolism, there was no evidence of therapeutic benefit.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Pruritus associated with intrathecal opioid administration is particularly common in pregnancy. Nonsteroidal anti-inflammatory drugs (NSAIDs) can reduce the severity of this pruritus but have undesirable side effects. The recent development of drugs that can specifically inhibit the cyclooxygenase 2 isoenzyme have become an attractive alternative. This study was designed to evaluate the efficacy of such a drug (celecoxib) in reducing intrathecal opioid-induced pruritus in a randomised double-blinded study of 60 women undergoing Caesarean section. All of them received spinal anaesthesia with 3 ml of 0.5% hyperbaric bupivacaine and 0.3 mg preservative-free morphine. After delivery of the baby, they received either oral celecoxib 200 mg or placebo. Visual analogue scores for pain and pruritus were measured at 30 min, 2, 4, 8, and 24 h. There was no difference in the severity and onset of pain and pruritus between the two groups. Timing of administration, inadequate dosing and possible altered pharmacokinetics in pregnancy may explain the lack of efficacy.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary This randomised, crossover study compared patient-controlled sedation using boluses of propofol and patient-maintained sedation using a target-controlled infusion of propofol. Twenty-three patients aged 18–35 years having surgical removal of bilateral third molar teeth under local anaesthesia during two separate visits were studied. In the majority of patients, both techniques provided moderate sedation, good operating conditions, stable physiological parameters and a high degree of patient satisfaction. Two patients became over-sedated during patient-controlled sedation. The time taken for titration to adequate sedation was longer with patient-maintained sedation than with patient-controlled sedation [mean (SD) = 8.6 (3.7) min vs. 5.7 (3.1) min, p 〈 0.005]. The mean overall propofol consumption was similar with both techniques. The majority of patients preferred patient-maintained sedation to patient-controlled sedation, p 〈 0.05.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

A randomised study was carried out in 60 anaesthetised patients with no evidence of airway difficulties, to compare the Williams Airway Intubator and the Ovassapian Fibreoptic Intubating Airway for bronchoscopic view and ease of railroading a tracheal tube during fibreoptic orotracheal intubation. The Williams Airway Intubator provided a better view of the glottis (41 (68.3%) unobstructed views) than the Ovassapian Fibreoptic Intubating Airway (15 (25%) unobstructed views; p 〈 0.0001) and a shorter time was needed to complete bronchoscopy (median (95% CI) difference 4 s (1–7); p = 0.01). Four (6.7%) bronchoscopies failed using the Williams Airway Intubator compared with 26 (43.3%) using the Ovassapian Fibreoptic Intubating Airway (p 〈 0.0001). Both airways provided similar intubating conditions when the glottis was visible.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Sixty unpremedicated healthy adult patients were studied during induction of anaesthesia with intravenous propofol delivered by a ‘Diprifusor’ target-controlled infusion. Bispectral index (BIS) and spectral edge frequency (SEF95) were measured concurrently with the predicted blood and effect site propofol concentrations. Logistic regression was used to calculate the predicted propofol blood and effect site concentrations required to produce unconsciousness and no response to a noxious stimulus in 50% and 95% of patients and to correlate BIS with these end-points. The Diprifusor TCI software produces anaesthesia at consistent target concentrations. Bispectral index correlates well with clinical end-points and may be useful during propofol anaesthesia.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have developed a system which allows patients to operate a target-controlled infusion of propofol to provide sedation and we have studied its use in 36 unpremedicated patients undergoing local and regional anaesthetic procedures lasting 10–280 min. An intravenous propofol infusion was started at a target plasma level of 1 μg.ml−1. The patient was able to increase the target propofol concentration in 0.2-μg.ml−1 increments by pressing a demand button. There was a lockout interval of 2 min and a maximum permissible target concentration of 3 μg.ml−1. There was considerable interindividual variability in propofol consumption (mean 39.3 μg.kg−1.min−1, range 3–131 μg.kg−1.min−1), no cardiovascular instability and little oversedation. Eight patients required supplementary oxygen. Optimal sedation was provided at median target concentrations of 0.8–0.9 μg.ml−1. The target-controlled infusion system bias was − 47% and the inaccuracy was 48%. Patient satisfaction was high and 89% said that they would definitely use the technique again. This technique combines the benefits of target-controlled infusion with patient-controlled feedback and produces safe intra-operative sedation.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We compared the efficacy of prophylactic ephedrine infusion over fluid preloading in prevention of maternal hypotension during spinal anaesthesia for Caesarean section. Forty-six women undergoing elective Caesarean section at term were allocated randomly to receive either intravenous fluid preloading with Hartmann's solution 20 ml.kg−1 (fluid group) or prophylactic intravenous ephedrine 0.25 mgkg−1 (ephedrine group). Moderate hypotension was defined as ≥ 20% reduction in systolic blood pressure and severe hypotension as ≥ 30% reduction in systolic blood pressure. Maternal uterine circulation was measured using Doppler ultrasound in 11 parturients before and after spinal anaesthesia. There was a lower incidence of severe hypotension in the ephedrine group compared with the fluid group (35% vs. 65%, p = 0.04), although the incidence of moderate hypotension was similar. Mean umbilical venous pH was higher in the ephedrine group than in the fluid group (7.33 vs. 7.29, p = 0.02) and the number of patients shivering was lower in the ephedrine group (2 vs. 9, p = 0.02). No difference was found between pre- and postspinal uterine artery pulsatility indices in either group. We conclude that prophylactic ephedrine infusion alone is at least as good as fluid preload alone in combating the hypotension associated with spinal anaesthesia for Caesarean section.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Pneumoperitoneum may be poorly tolerated in patients with marginal cardiopulmonary function. Transoesophageal echocardiography is a relatively non-invasive technique that can track changes in left ventricular cavity area using acoustic quantification and has been found to provide a reliable, real-time estimation of left ventricular function. We evaluated mid-papillary fractional area change during pneumoperitoneum in 17 healthy adult patients (group 1) and 17 with hypertension and/or ischaemic heart disease (group 2) undergoing laparoscopic cholecystectomy. Peritoneal insufflation led to significant (p 〈 0.01) decreases in fractional area change and an increase in mean blood pressure. There was no significant change in heart rate. Patients with cardiovascular disease who had a 〉 30% decrease in fractional area change following carbon dioxide insufflation (group 2B) were given an intravenous infusion of glyceryl trinitrate. In groups 1 and 2A, fractional area change improved slightly with head-up tilt and continued to improve over the course of surgery. Glyceryl trinitrate led to a significant increase in fractional area change and a decrease in mean blood pressure back to baseline values. We conclude that peritoneal insufflation of carbon dioxide results in a significant increase in cardiac workload that is well tolerated in patients with no cardiovascular disease. Coexisting cardiovascular disease can result in even more pronounced impairment of cardiac function, which may not be predictable by clinical assessment or adequately determined by routine monitoring. We recommend the use of transoesophageal acoustic quantification as a monitor in these patients and the administration of glyceryl trinitrate to ameliorate myocardial stress.

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