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Biomedical subjects

R J Carr

Publications and source records attributed to R J Carr.

At least 19 recordsLinked to original sources
PubMed2002

Paediatric transcranial surgery: a review of 114 consecutive procedures.

Craniofacial units have a responsibility to collect data, to promote research and training and to carry out audit. We present a review of 114 consecutive transcranial procedures performed in 110 children in our unit over an 8 year period, with particular reference to complications. There were no deaths in this series. Complications included two cases of excessive intraoperative blood loss necessitating a delay in the procedure, and two postoperative infections that required aggressive antibiotic management. Minor complications, delaying hospital discharge, occurred in 13 patients. Within the range of paediatric transcranial procedures performed, the potential for complications is greater for complex osteotomies in syndromic conditions than for single sutural synostosis correction. The transcranial case mix included a relatively small number of craniofacial dysostoses, which contributes to the very low complication rate reported. This report demonstrates that multidisciplinary assessment and planning, adherence to craniofacial surgical principles, shorter operating times and avoidance of high-risk procedures contribute to a low complication rate, and confirms that paediatric transcranial procedures can be safely performed in dedicated centres where there is a multidisciplinary team with appropriate commitment and experience.

Adolescent↗
PubMed2000

Ectopic pregnancy.

Ectopic pregnancy occurs in approximately 2% of all pregnancies in the United States, and is the nation's leading cause of first trimester maternal death. Its incidence has increased sixfold in the past 25 years, despite significant improvements in techniques for early diagnosis and management. This article reviews the epidemiology, risk factors, and common clinical presentations of ectopic pregnancy. Both traditional and newly developed strategies for diagnosis and management are described. The primary care physician is in an excellent position to screen for and diagnose ectopic pregnancy, and to counsel patients regarding treatment options and future risks. With the increasing trend toward outpatient nonsurgical management of ectopics, it is expected that the roll of the primary care physician in managing patients with ectopic pregnancy will continue to increase.

Abortifacient Agents, Nonsteroidal↗
PubMed2000

Living related liver transplantation in infants and children: report of anesthetic care and early postoperative morbidity and mortality.

STUDY OBJECTIVE: To determine those infants at high risk for perioperative complications and mortality following living, related liver transplantation. DESIGN: Retrospective chart review. SETTING: Large metropolitan teaching hospital. MEASUREMENTS AND MAIN RESULTS: The charts and anesthetic records of the 12 infants and children who received the left lateral hepatic segment from a living relative the past 2 years at our institution were reviewed. The records were examined to determine the causes of perioperative morbidity and to identify patients at high risk for serious complications and mortality. All infants and children (mean +/- SD age, 29+/-30 months; weight, 13.6 +/-6.8 kg) survived the operation (8.3+/-1.7 hours) without intraoperative complications. The average blood loss, including 500 mL of recipient blood used to flush the liver before reperfusion, was 1483 +/-873 mL (119+/-70 mL/kg). Three infants developed portal vein thrombosis, and one of these infants also had hepatic artery thrombosis. The risk of vessel thrombosis was significantly higher (3/3 vs. 0/9; p<0.0045) in infants less than 9 kg body weight, as was the risk of death (2/3 vs. 0/9; p<0.045). Both children who died had vascular thrombosis. Other serious complications were bleeding, 6; infection, 7; acute rejection, 3; and bile leak, 2. CONCLUSIONS: Infants and children can successfully undergo living, related liver transplantation. However, the risks of vascular complications and death are greater in infants less than 9 kg body weight.

Anesthesia↗
PubMed1999

Differential diagnosis of thyroid crisis and malignant hyperthermia in an anesthetized porcine model.

The intra-operative differential diagnosis between thyroid crisis and malignant hyperthermia can be difficult. Also stress alone can trigger MH. The purposes of this study were: 1) to investigate the metabolic and hemodynamic differences between thyroid crisis and MH, 2) determine how thyroid crisis affects the development of MH, and 3) determine if the stress of thyroid crisis can trigger MH in susceptible individuals. We studied MH susceptible and normal swine. Two groups of animals (MH susceptible and normal) were induced into thyroid crisis (critical core hyperthermia, sustained tachycardia and increase in oxygen consumption) by pretreatment with intraperitoneal triiodothyronine (T3) followed by large hourly intravenous injections of T3. Two similar groups were given intravenous T3 but no pretreatment. These animals did not develop thyroid crisis and served as controls. Thyroid crisis did not result in metabolic changes or rigidity characteristic of an acute episode of MH. When the animals were subsequently challenged with MH triggering agents (halothane plus succinylcholine) dramatic manifestations of fulminant MH episodes (acute serious elevation in exhaled carbon dioxide, arterial CO2, rigidity and acidemia) were noted only in the MH susceptible animals. Although thyroid crisis did not trigger MH in the susceptible animals it did decrease the time to trigger MH (14.1 +/- 7.2 minutes versus 47.2 +/- 17.7 minutes, p < 0.01) in susceptible animals. Hormone induced elevations in temperature and possibly other unidentified factors during thyroid crisis may facilitate the triggering of MH following halothane and succinylcholine challenge.

Animals↗
PubMed1997

Characterisation of the meningococcal transferrin binding protein complex by photon correlation spectroscopy.

Photon correlation spectroscopy demonstrated for the first time that co-purified meningococcal TbpA+B form a complex in solution. This structure bound hTf and the resultant species underwent partial dissociation after exposure to additional hTf or following prolonged incubation. Purified TbpA and TbpB had similar apparent sizes but showed distinctive size profiles suggesting that TbpA forms a largely homogeneous population while TbpB may produce more variable particle sizes under these conditions.

Bacterial Outer Membrane Proteins↗
PubMed1996

Prior hypothermia attenuates malignant hyperthermia in susceptible swine.

This study was designed to determine the extent by which mild or moderate hyperthermia attenuates the triggering of malignant hypothermia (MH) induced by the combined administration of halothane and succinylcholine. Sixteen susceptible swine were initially anesthetized with nontriggering drugs and then either kept normothermic (approximately equal to 38 degrees C, n = 6) or cooled to induce mild (approximately equal to 35 degrees C, n = 6), or moderate (approximately equal to 33 degrees C, n = 4) hypothermia. Next, after a 30-min control period, the normothermic and mildly hypothermic animals were administered 1 minimum alveolar anesthetic concentration (MAC) halothane followed by a bolus dose of succinylcholine (2 mg/kg). Within 10 min all normothermic animals developed fulminant MH, whereas the onset of MH was slowed or was absent in the mildly hypothermic group. To test whether moderate hypothermia could more effectively minimize the signs of a MH episode, this group of animals was exposed to 1.5 MAC halothane followed 10 min later by a 3-mg/kg bolus of succinylcholine. MH was not induced and anesthesia was then changed to nontriggering drugs (ketamine and pancuronium). The animals were then aggressively rewarmed to 38 degrees C: a slight increase in the ETCO2 was detected, but MH episodes did not spontaneously occur. Subsequently, the readministration of halothane and succinylcholine rapidly provoked fulminant MH. We concluded that the induction of mild hypothermia impairs triggering and reduces the progression of MH induced by the combined administration of halothane and succinylcholine, whereas moderate hypothermia was completely protective and thus could be considered for prophylaxis.

Animals↗
PubMed1994

Clinical assessment of the Augustine Guide for endotracheal intubation.

The Augustine Guide (AG) allows oral endotracheal intubations to be performed blindly; head and neck manipulation are unnecessary. It is a premolded device designed to fit in a lock and key fashion in the glottis, thus serving as a guide to allow blind laryngeal insertion of an endotracheal tube. Intubation success rate with the AG was studied in 100 adults intubated by the same individual; head and neck were held neutral. Intubations were described as easy if they were successful in the first attempt and difficult when more than one attempt to position the AG was necessary. Endotracheal intubation was successful 94% of the time and was easy in 71%. Repositioning of the AG was necessary in 23%. Patients with jaw abnormalities required repositioning more often (P < 0.05). Esophageal intubation did not occur. Minor trauma was noted in 18% of subjects. The AG is a safe and effective tool for blind orotracheal intubation.

Adolescent↗
PubMed1993

Public health medicine training.

Training in public health medicine uses a 'trainer-trainee' model for learning similar to that used in general practice. In order to examine the quality of training in the South Western region of the UK, a questionnaire was devised to assess both adequacy and importance of various factors for training. The results of the survey identified key areas for further discussion and were used as the basis of an interactive study day. One interesting finding was the difference in perceptions of trainers and trainees, possibly illustrating the differences between trainees' 'demands' and trainers' perceptions of trainees' 'needs'.

Attitude of Health Personnel↗
PubMed1992

Infantile fibromatosis with involvement of the mandible.

Two unusual cases of infantile fibromatosis involving the mandible occurring in 2-year-old children are described. These tumours, though initially highly aggressive, underwent spontaneous regression in the absence of definitive treatment.

Cell Nucleus↗
PubMed1991

Analysis of pH-induced population oscillations of Saccharomyces cerevisiae and Escherichia coli using photon correlation spectroscopy.

Following a recent successful application of p.c.s. to liquid chromatography in the biotechnology industry, its usefulness as a contamination monitor in the fermentation industry was assessed. It was found that: (i) the intensity bias of the technique limits its uses to the detection of contaminants when they are larger than the host; (ii) the inherent heterogeneity of microbial cultures prevents the use of multiangle studies, and (iii) the large size of bacteria make the use of p.c.s. in flowing, on-line systems impractical.

Absorptiometry, Photon↗
PubMed1991

On the design of looped orthodontic retainer wires.

Removable Hawley orthodontic retainers have long been prescribed by clinicians following completion of active therapy. Only minor changes have occurred in the design of the retainer over the past 40 years. Structural, in-service failures of this appliance are typically: 1) permanent (inelastic) deformation of the as-prepared labial bow from masticatory action that induces unwanted force transmitted by the appliance to the dentition; or 2) accumulated material damage from removal and replacement of the retainer that eventually results in fracture of the labial bow. This paper reports the results of a series of experimental studies; the overall objective was the optimization of the appliance design, focusing on the labial bow. Wire size, material, temper, canine-loop height, markings for bend placements, heat-treatment of the prepared bow, and two procedures for removing and replacing the appliance were investigated. The collective outcomes suggest a combination of design-parameter values to help maximize the life of the labial bow of the retainer.

Analysis of Variance↗
PubMed1990

Physico-chemical properties of recombinant desulphatohirudin.

Physico-chemical properties of recombinant desulphatohirudin expressed in yeast (CIBA GEIGY code No. CGP 39393) were reinvestigated. As previously reported for natural hirudin, the recombinant molecule exhibited abnormal behaviour by gel filtration with an apparent molecular weight greater than that based on the primary structure. However, molecular weight estimation by SDS gel electrophoresis, FAB-mass spectrometry and Photon Correlation Spectroscopy were in agreement with the theoretical molecular weight, with little suggestion of dimer or aggregate formation. Circular dichroism studies of the recombinant molecule show similar spectra at different pH values but are markedly different from that reported by Konno et al. for a natural hirudin-variant. Our CD studies indicate the presence of about 60% beta sheet and the absence of alpha helix in the secondary structure of recombinant hirudin, in agreement with the conformation determined by NMR studies.

Chemical Phenomena↗
PubMed1990

Osteomyelitis of the mandible: a complication of routine dental extractions in alcoholics.

Osteomyelitis is a rare sequel to a dental extraction. Three cases are described where osteomyelitis followed routine dental extractions in patients with a history of alcoholism. It is suggested that depression of the host's defences, due to alcoholism, modified the response to and the spread of this serious infection. Such patients represent a high risk group and should be identified prior to treatment to avoid unnecessary complications.

Abscess↗
PubMed1989

Multiple primaries in mouth cancer--the price of success.

Successful locoregional control in the treatment of oral cancer has been achieved at the expense of an increase in the occurrence of distant metastases and the emergence of second primary tumours. The head and neck are the commonest sites for second primaries which occur in 10 to 20% of patients. This study represents a detailed prospective analysis of 105 oral squamous cell carcinomas which could be followed-up until death or March 1987. Recently, interest has been focused on the role of screening such patients using triple endoscopy not only at initial diagnosis and assessment of the index tumour but also at follow-up after definitive treatment. However, the outlook for these patients is so poor, as confirmed by this study, that screening of frail elderly patients is hard to justify.

Adult↗