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J Plummer

Publications and source records attributed to J Plummer.

At least 19 recordsLinked to original sources
PubMed2006

Sub-Tenon block: a learning curve of 100 cases.

This study measures the learning curve for accomplishing sub-Tenon blocks for ophthalmic surgery applicable to anaesthetists skilled in peribulbar techniques. We defined criteria for a good block in terms of chemosis, subconjunctival haemorrhage, globe movement and the need for additional peribulbar block. The overall success rate, by our definitions, was 72% and 56% for the two operators. The overall requirement for an additional peribulbar block was 10%. The rate of additional blocks and reduction in globe movement reached a plateau after about 60 procedures for both operators. The rates of chemosis (6% and 12% overall) and subconjunctival haemorrhage (6% and 12% overall) did not trend with increased experience. The results applied to both a cataract and a vitreo-retinal surgery casemix.

Adolescent↗
PubMed2005

Evaluation of the SLIPA (streamlined liner of the pharynx airway), a single use supraglottic airway device, in 60 anaesthetized patients undergoing minor surgical procedures.

The Streamlined Liner of the Pharyngeal Airway, SLIPA (Hudson RCI) is a new disposable supraglottic airway device that has no inflatable cuff and has features designed to reduce aspiration risk. This study aimed to assess the insertion success and effectiveness of the SLIPA in 60 patients who presented for elective surgery. Ethics committee approval was obtained. Patients were excluded if they were less than 18 years, had not provided written consent or were at risk of pulmonary aspiration. The first 20 SLIPA were inserted by the principal investigator (Group A) followed by another 40 inserted by medical officers and anaesthetists of varying experience (Group B). Twenty-one males and 39 females were recruited into the study. Median time to ventilation was 20.4 seconds in Group A (range 12.9-109) and 24.8 seconds in Group B (range 8.2-82.5). Overall success rate was 100% in Group A and 92.5% in Group B. The lowest recorded SpO2 was 91% in Group B. The incidence of blood and sore throat score >3 (0-10 scale) was 23% and 7% respectively (Groups A and B). Group B reported that use of the device was very easy in 16%, easy in 76%, difficult in 5%, and very difficult in 3%. The SLIPA proved to be a reliable airway providing adequate ventilation in both spontaneous breathing and assisted respiration. Most users found the SLIPA to be easy or very easy to use.

Adult↗
PubMed2002

Learning to apply effective cricoid pressure using a part task trainer.

An anatomically-correct model of a larynx inside a head and neck model was constructed so that the location, direction and amount of force applied to the neck could be measured. Fifty trained staff from three general hospitals were then asked to apply cricoid pressure on the model. None was able to state the force that should be applied (30 N), and only five (10%) actually applied cricoid pressure effectively. After training using the model, 45 (90%) applied cricoid pressure correctly (p < 0.001). This study demonstrates that improved training in cricoid pressure is needed and supports earlier researchers who suggested that this can be achieved using simulators.

Anesthesiology↗
PubMed2000

Insulin infusions in the neonatal unit: delivery variation due to adsorption.

OBJECTIVE: To assess the extent of the variability in insulin delivery over time, under conditions used in Australian neonatal units, studying the following variables: diluent, preconditioning, flushing, sequential preconditioning and flushing, insulin concentration, flow rate, catheter type, and addition of albumin. METHODOLOGY: A range of simulated insulin infusions was studied. Infusions were run over 22 h, with aliquots of infusate collected at baseline and after 15 min, 30 min, 1 h, 2 h, 6 h and 22 h. Insulin concentration was assayed using a radioimmunoassay. RESULTS: An infusion of 50 mU insulin/mL at 1 mL/h gave negligible insulin delivery until 22 h. However, after preconditioning and flushing the tubing, consistent insulin delivery was attained by 6 h. An infusion of 200 mU insulin/mL at 1 mL/h did not provide consistent delivery until 6 h. At this concentration and rate, consistent insulin delivery was attained within 30 min of the start of the infusion either by preconditioning and flushing the tubing, or by addition of albumin to the infusate. CONCLUSION: Clinically significant variation in intravenous insulin delivery will occur in the neonatal setting unless counter-measures are taken, such as sequential preconditioning and flushing of the delivery system or the addition of albumin to the infusate.

Adsorption↗
PubMed2000

Effect of short-term ketorolac infusion on recovery following laparoscopic day surgery.

This study tested the hypothesis that, by the addition of parenteral ketorolac to an oral analgesic regimen for one day following laparoscopic surgery, analgesia would be improved and thus the return of normal function hastened. Seventy-two female patients were randomly assigned to receive ketorolac 10.5 mg subcutaneously at the end of surgery followed by a subcutaneous infusion of 1.75 mg/h for 24 to 36 hours, or an equivalent volume of saline. All patients were provided with codeine tablets (30 mg) for analgesia if required. For the first four postoperative days patients recorded details of pain, side-effects and discomfort on performing everyday activities. Patients who received ketorolac received significantly less fentanyl in the Recovery Ward and significantly less codeine prior to discharge than the saline group. They also took significantly fewer codeine tablets over the four-day postoperative period. Pain scores in the ketorolac group were not significantly lower than in the saline group on the first postoperative day (P = 0.052) and subsequently remained similar. Levels of discomfort on performing six common activities were similar in the two groups over the four-day postoperative period. We conclude that, despite beneficial effects during the period of ketorolac administration, there was no continuing benefit after this time other than reduced analgesic use, and no improvement in the patients' ability to perform common activities.

Adolescent↗
PubMed1998

Relationship of renal size, body size, and blood pressure in children.

Somatometric parameters, renal size, and systolic blood pressure (SBP) were studied in 406 patients referred to pediatric nephrology and urology clinics. These patients included 269 females (66%), 67 African Americans (17%), and 87 patients with essential hypertension (21%). Z scores for the study population were comparable to published standards for height, kidney length, and SBP. Weight and body mass index scores were significantly greater than predicted from the standards, especially in the subset of patients with essential hypertension. Age, height, weight, body mass index, kidney length, and SBP all correlated with one another; however, on multiple regression analysis of SBP with the other five independent variables, only weight proved to have a significant correlation. Furthermore, the relationship of kidney length with SBP was positive and hypertensive patients had greater kidney size than published standards. These data do not support reduced kidney size in the population with essential hypertension, nor is there support for a convincing correlation between kidney length and SBP in the general pediatric population. Body weight correlates best with blood pressure. These findings warrant further study in a less-select population. Prevention and treatment of obesity may thus be of prime importance in addressing hypertension in children.

Adolescent↗
PubMed1998

Lack of efficacy of propofol in the treatment of early postoperative nausea and vomiting.

The anti-nauseant efficacy of low-dose propofol was investigated in a blinded, randomized trial. Patients who complained of nausea and/or vomiting following laparoscopic gynaecological surgery and who requested antiemetic were randomly assigned to receive placebo, propofol 3 mg, propofol 9 mg or propofol 27 mg by intravenous injection. Nausea, vomiting and sedation were recorded by a blinded observer for 90 minutes following administration of the test drug, prior to discharge, and 24 hours following surgery. Rescue antiemetic (droperidol 1.0 mg i.v.) was available from 10 minutes after administration of test drug. Propofol failed to reduce nausea scores and did not reduce the incidence of vomiting. Numbers of patients receiving rescue antiemetic were similar in the four treatment groups. In the first 10 minutes following test drug administration, sedation scores were increased by propofol in a dose-related manner. We conclude that, in the dose range studied, propofol is ineffective for the treatment of nausea and vomiting occurring soon after laparoscopic gynaecological surgery.

Adult↗
PubMed1997

Molecular cloning of mannose-6-phosphate reductase and its developmental expression in celery.

Compared with other primary photosynthetic products (e.g. sucrose and starch), little is known about sugar alcohol metabolism, its regulation, and the manner in which it is integrated with other pathways. Mannose-6-phosphate reductase (M6PR) is a key enzyme that is involved in mannitol biosynthesis in celery (Apium graveolens L.). The M6PR gene was cloned from a leaf cDNA library, and clonal authenticity was established by assays of M6PR activity, western blots, and comparisons of the deduced amino acid sequence with a celery M6PR tryptic digestion product. Recombinant M6PR, purified from Escherichia coli, had specific activity, molecular mass, and kinetic characteristics indistinguishable from those of authentic celery M6PR. Sequence analyses showed M6PR to be a member of the aldo-keto reductase superfamily, which includes both animal and plant enzymes. The greatest sequence similarity was with aldose-6-phosphate reductase (EC 1.1.1.200), a key enzyme in sorbitol synthesis in Rosaceae. Developmental studies showed M6PR to be limited to green tissues and to be under tight transcriptional regulation during leaf initiation, expansion, and maturation. These data confirmed a close relationship between the development of photosynthetic capacity, mannitol synthesis, and M6PR activity.

Amino Acid Sequence↗
PubMed1995

Genetics of primary and timing effects in the mnd mouse.

The mnd mouse shows a spontaneous adult-onset hereditary neurological disease, with motor abnormality by 6 months of age, progressing to severe spastic paralysis and premature death. The disease is autosomal recessive, with heterozygote effects seen under stress. It maps to mouse chromosome (chr) 8. Histopathology with Nissl stains documents substantial abnormalities of upper and lower motor neurons, and there is retinal degeneration beginning in the first month, even without light exposure. Increasing levels of autofluorescent lipopigment are found in both neuronal and non-neuronal tissues as the mnd mice age. Recently, NCL-like inclusions and accumulating subunit c have also been described. When mnd is outcrossed to the AKR/J genetic background, ca. 40% of the mnd/mnd F2 progeny show early onset (onset by 4.5-5 months and death by 7 months.) This accelerated timing effect seems to be strain-specific, and unlinked to the mnd gene itself. Our current working hypothesis is that the timing effect is due to 2 or 3 unlinked dominant genes with incomplete penetrance at any single locus. In a combined RFLP/PCR fragment genetic analysis, the strongest deviation from the expected ratio of AKR vs B6 alleles occurs with markers on proximal half of chr 1. Additional loci on chrs 5 and 10 may also be involved. The mechanism of interaction of these modifying genes with the primary mnd gene may offer new therapeutic avenues.

Animals↗
PubMed1995

Accelerated and widespread neuronal loss occurs in motor neuron degeneration (mnd) mice expressing a neurofilament-disrupting transgene.

To examine the effects of multiple stressors on the onset and specificity of a neurodegenerative disease, we derived mnd/mnd mice expressing a neurofilament-H/lacZ transgene. The mnd mutation causes adult-onset motor dysfunction, and produces abnormal ubiquitous accumulation of autofluorescent lipopigment, with retinal degeneration and late-onset motor neuron degeneration. The neurofilament H-beta-galactosidase fusion protein causes endogenous neurofilament subunits to precipitate in perikarya, but shows neither significant neuronal degeneration nor behavioral changes until advanced age. In mnd/mnd-transgenic animals, neurological symptoms, lipopigment accumulation, and motor neuron loss were substantially accelerated. Newly vulnerable populations of neurons also degenerated, including cerebellar Purkinje cells and dorsal roots. This study exemplifies a synergistic interaction between a neuron-specific and a ubiquitous defect, leading to significant neurological consequences. It further indicates that cytoskeletal abnormalities similar to those observed in late-onset human neurodegenerative disorders can interact with other cellular defects and contribute to pathogenesis.

Animals↗
PubMed1995

Additive interactions between propofol and ketamine when used for anesthesia induction in female patients.

BACKGROUND: Propofol and ketamine may be paired for anesthesia induction and for total intravenous anesthesia. The nature of any sedative interactions occurring between propofol and ketamine are unknown. The combination when used for anesthesia induction in female patients was studied. METHODS: Quantal dose-response curves were determined in 180 female patients to whom the drugs were administered individually and in combination. Two minutes after administering the drugs, two endpoints were assessed. First, loss of response to verbal command (hypnosis) and then, in those who failed to respond to this endpoint, loss of response to a 5-s transcutaneous tetanus (anesthesia). Interactions were analyzed by fitting the data to a mathematical model in which response was analyzed in terms of the doses of the two drugs and an additional term included to describe nonadditive interactions. The incidences of apnea, arterial pressure, and heart rate changes during the first 5 min were recorded. RESULTS: At the hypnotic endpoint, the ED50s were 1.10 mg/kg propofol (95% CIs 0.93-1.27), 0.39 mg/kg ketamine (95% CIs 0.27-0.46), and the combination of 0.63 mg/kg propofol and 0.21 mg/kg ketamine (95% CIs 0.53/0.18-0.73/0.24). At the anesthetic endpoint, the ED50s were 1.85 mg/kg propofol (95% CIs 1.58-2.36) 0.66 mg/kg ketamine (95% CIs 0.58-0.77), and the combination of 1.05 mg/kg propofol and 0.35 mg/kg ketamine (95% CIs 0.88/0.29-1.27/0.42). The effects were additive at both endpoints; there was no evidence of an interaction. The ED50s for apnea were 1.61 mg/kg propofol (95% CIs 1.39-1.94), greater than 0.85 mg/kg ketamine and for the combination 1.50 mg/kg propofol and 0.50 mg/kg ketamine (95% CIs 1.15/0.38-3.09/1.03). The addition of ketamine did not significantly alter the ED50 for apnea of propofol. There was a significant difference in the arterial pressures among the three groups (P < 0.001). Using the combination, the cardiostimulant effects of ketamine balanced the cardiodepressant effects of propofol. There was no change in arterial pressure or heart rate after the noxious stimulus. CONCLUSIONS: When using the combination, doses were additive at hypnotic and anesthetic endpoints. Ketamine had no influence on the incidence of apnea after propofol, and the net hemodynamic effects were minimal.

Adult↗
PubMed1995

Variable-dose patient-controlled analgesia. A preliminary report.

One size of patient-controlled analgesia demand dose does not suit all patients after surgery. We have constructed a new patient-controlled analgesia (variable-dose patient-controlled analgesia) in which patients have a choice of demand dose sizes. In an initial trial, patients could choose between 0.5, 1.0 or 1.5 mg morphine. Patients readily understood the system and were all 'satisfied' (n = 1) or 'very satisfied' (n = 9) with the system. Only two patients sought 'complete relief' from pain, most reported seeking 'moderate relief'. All patients obtained a 'lot of relief' or 'complete relief' with this patient-controlled analgesia system. This preliminary experience suggests that variable dose patient-controlled analgesia warrants further investigation and comparison with conventional patient-controlled analgesia.

Analgesia, Patient-Controlled↗
PubMed1995

Iron overload facilitates hepatic fibrosis in the rat alcohol/low-dose carbon tetrachloride model.

The role of iron deposition in initiating hepatic fibrosis in iron overload disorders is not clearly established, and it is becoming increasingly recognized that iron may be interacting with other potential liver-damaging agents. The authors therefore examined the interplay of iron and alcohol in rats administered subtoxic doses of carbon tetrachloride (CCl4) vapor at 20 ppm in customized chambers. At birth, the offspring of seven pregnant Porton rats were divided into two groups: one group was fed a normal rat chow diet and the other a diet supplemented with 3% (w/w) carbonyl iron for 10 weeks after weaning. In this latter group, the mothers were fed an iron supplement while breastfeeding. At 10 weeks, the animals from the first group (normal chow) were divided into two groups of six animals and fed a Lieber-DeCarli liquid diet with daily exposure to CCl4 vapor: group 1, liquid diet+CCl4; group 2, liquid diet+alcohol 150 kcal/l+CCl4. The animals from the second iron-supplemented group were divided into two groups of six animals and fed a liquid diet with 3% (w/v) carbonyl iron and exposed to CCl4 vapor for 10 weeks: group 3, liquid diet+iron+CCl4; group 4, liquid diet+iron+alcohol supplement+CCl4. Two animals from each group of six had a liver biopsy at 4, 6, and 8 weeks, and all animals were killed after 10 weeks of CCl4 exposure. After the first 10-week iron loading period, the rats fed the carbonyl iron-supplemented diet had a 10-fold elevation in hepatic iron concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Accumulating autofluorescent material as a marker for early changes in the spinal cord of the Mnd mouse.

The mouse mutant Motor neuron degeneration (Mnd) displays an adult-onset progressive degeneration of upper and lower motor neurons, with mild symptoms recognizable at 6 months, leading to spastic paralysis and premature death at 10-12 months on the C57B1/6 background. Despite this late onset, abnormally-accumulating autofluorescent material can be seen in both the spinal cord and other regions as early as the first month. This pigmented material is present in both increasing numbers of cells, and in increasing amounts within individual cells, as the animals age. Motor neurons then go on to degenerate, while most other cell types stabilize. The level of pathological involvement, well before the onset of clear clinical symptoms, suggests that the full degenerative process is an extremely gradual and protracted one with some selectivity for motor neurons.

Animals↗
PubMed1993

Synaptosomal glutamate uptake declines progressively in the spinal cord of a mutant mouse with motor neuron disease.

It has been suggested that the degeneration of motor neurons in amyotrophic lateral sclerosis is a consequence of excitotoxicity resulting from a loss of synaptosomal glutamate uptake. The role of synaptosomal glutamate uptake in the pathogenesis of motor neuron disease was studied in the Mnd mouse. Glutamate uptake in spinal-cord synaptosomes declined in parallel with the onset of behavioral deficits in Mnd mice but lagged considerably behind the appearance of pathology in motor neurons. Glutamate uptake did not decline significantly in corpus striatum, and GABA uptake did not change significantly in either spinal cord or striatum. The presence of pronounced histopathological changes before the loss of glutamate uptake suggests that the decline of glutamate uptake is a consequence rather than the primary cause of motor neuron disease in the Mnd mouse.

Animals↗
PubMed1992

Novel developmental boundary in the cerebellum revealed by zebrin expression in the lurcher (Lc/+) mutant mouse.

The cerebellar cortex contains at least two classes of Purkinje cells, which are organized into alternating arrays of parasagittal bands. The clearest demonstration of this compartmentation is the pattern of expression of a family of polypeptide antigens, the zebrins, which are expressed selectively by Purkinje cell subsets. Furthermore, anterograde tracing experiments show that the zebrin compartments are closely correlated with both afferent and efferent projection maps. The further subdivision of long parasagittal bands into smaller modules may occur through several different mechanisms, including the intrinsic cerebellar lobulation and the selective distribution of afferent terminal fields. However, while the longitudinal subdivisions are straightforwardly shown, the mediolateral boundaries are more subtle. In this report we describe a novel mediolateral and anteroposterior compartmentation boundary in mice, running across lobule VIII, that is revealed by the consequences of the lurcher (Lc/+) allele for zebrin expression. In normal mice zebrin compartmentation develops in several discrete stages: until postnatal day 5 (PD5) there is no zebrin expression; from PD5-PD7 zebrin is found only in the posterior lobe vermis, with immunoreactive Purkinje cells in lobules X, IX, and VIII but not elsewhere; from PD7-PD12 most Purkinje cells in the vermis become zebrin+; from PD12-PD15 immunoreactivity also appears in the hemispheres so that almost all Purkinje cells now are zebrin+; and finally, from PD15-PD25 zebrin is gradually suppressed in those Purkinje cells that are zebrin- in the adult until the mature pattern of parasagittal compartments is revealed. In the Lc/+ mutant the normal developmental progression is interrupted at around PD7. As a result, the pattern of zebrin expression becomes frozen at that stage when immunoreactive Purkinje cells are confined exclusively to the posterior lobe vermis. A reproducible boundary between expressing and nonexpressing zones runs mediolaterally across the dorsal surface of lobule VIII. Apart from zebrin expression itself, there are no obvious structural correlates of this transition. This mediolateral boundary identifies a developmental unit in the posterior lobe vermis of the cerebellum, and provides further evidence that the cerebellum is a highly heterogeneous structure.

Animals↗
PubMed1992

Mapping of the motor neuron degeneration (Mnd) gene, a mouse model of amyotrophic lateral sclerosis (ALS).

The motor neuron degeneration mutation (Mnd) causes a late-onset, progressive degeneration of upper and lower motor neurons in mice. After establishing genetic and environmental conditions that distinguish the phenotypes of Mnd/Mnd from +/Mnd mice, Mnd was mapped to proximal Chr 8, using endogenous retroviruses as markers. The map location was confirmed with additional linked polymorphic markers. The outcross/intercross matings to the strain AKR/J, which were used to follow the segregation of the retroviral markers with respect to Mnd, also revealed the existence of a timing effect. Approximately one-fourth of the affected Mnd/Mnd F2 progeny showed accelerated disease. The Mnd mouse model should allow study of mechanisms affecting onset and progression of specific neuronal degeneration in both animal and human neurological disease.

Age Factors↗