F18-FDG-PET evaluation of patients for resection of colorectal liver metastases

BACKGROUND/AIMS

Liver resection is the only treatment which offers long-term survival for patients with colorectal liver metastases. However, the significant mortality and morbidity associated with hepatectomy makes accurate patient selection paramount. Current staging by CT and MRI has limitations, with these modalities delivering a sensitivity and specificity of only 70-80%. Thus some patients may be deprived of long-term survival, and others subjected to futile surgery.

METHODOLOGY

We report our experience of the influence of F18-FDG-PET scanning in the management of 31 consecutive patients with colorectal liver metastases referred for liver resection.

RESULTS

F18-FDG-PET scanning detected liver and pulmonary metastases with a sensitivity of 96% and 100% respectively, in comparison to corresponding figures of 70% and 83% for CT. Furthermore, the sensitivity of F18-FDG-PET scanning in identifying extra-hepatic and extra-pulmonary disease was 100% in comparison to 20% for CT. Overall, F18-FDG-PET scanning resulted in a significant alteration of management in 29% of patients.

CONCLUSIONS

F18-FDG-PET scanning has an important clinical impact on the management of patients being considered for resection of colorectal liver metastases.

The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)

The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline.

Genome sequence of the Brown Norway rat yields insights into mammalian evolution

The laboratory rat (Rattus norvegicus) is an indispensable tool in experimental medicine and drug development, having made inestimable contributions to human health. We report here the genome sequence of the Brown Norway (BN) rat strain. The sequence represents a high-quality 'draft' covering over 90% of the genome. The BN rat sequence is the third complete mammalian genome to be deciphered, and three-way comparisons with the human and mouse genomes resolve details of mammalian evolution. This first comprehensive analysis includes genes and proteins and their relation to human disease, repeated sequences, comparative genome-wide studies of mammalian orthologous chromosomal regions and rearrangement breakpoints, reconstruction of ancestral karyotypes and the events leading to existing species, rates of variation, and lineage-specific and lineage-independent evolutionary events such as expansion of gene families, orthology relations and protein evolution.

Effect of experimental diabetes mellitus on gentamicin-induced acute renal functional changes in the anaesthetized rat

1. Rats with streptozotocin (STZ) diabetes are protected from gentamicin (GEN) nephrotoxicity. Because the chronic renal damage from GEN is preceded by acute renal functional changes (notably hypercalciuria), the present study aims to determine whether diabetes may also protect against the acute effects of the drug. If there is a link between the rapid physiological actions of GEN and its subsequent nephrotoxicity, the former may also be affected by the diabetic condition. 2. Standard renal clearance techniques were performed on anaesthetized rats that had been injected with STZ or vehicle 2 weeks previously. All animals were infused with 0.9% NaCl for 5 h and then either GEN (0.28 mg/kg per min) or 0.9% NaCl alone for 2 h. 3. Baseline fractional calcium excretion (FE(Ca)) of diabetic rats was three-fold that of control animals (6.6+/-0.2 vs 2.2+/-0.2%, respectively; P<0.01, MANOVA). Following GEN infusion, a comparable increase in FE(Ca) occurred in control and diabetic rats (5.3+/-0.6 vs 5.3+/-0.8%, respectively; NS). 4. Streptozotocin diabetes, therefore, does not alter the acute hypercalciuric response to GEN. This may suggest that the acute effects of GEN on renal calcium handling do not contribute to the subsequent nephrotoxicity. However, the higher baseline FE(Ca) seen in diabetic rats may afford protection against the renal injury caused by gentamicin.

Acute gentamicin-induced hypercalciuria and hypermagnesiuria in the rat: dose-response relationship and role of renal tubular injury

1. Standard renal clearance techniques were used to assess the dose-response relationship between acute gentamicin infusion and the magnitude of hypercalciuria and hypermagnesiuria in the anaesthetized Sprague-Dawley rat. Also investigated were whether these effects occurred independently of renal tubular cell injury. 2. Acute gentamicin infusion was associated with a significant hypercalciuria and hypermagnesiuria evident within 30 min of drug infusion. The magnitude of these responses was related to the dose of drug infused (0.14-1.12 mg kg(-1) min[-1]). Increased urinary electrolyte losses resulted from a decreased tubular reabsorption of calcium and magnesium. 3. A rapid dose-related increase in urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion was also observed in response to gentamicin infusion. However, there was no evidence of renal tubular cell injury and no myeloid bodies were observed within the lysosomes of the proximal tubular cells. Gentamicin may thus interfere with the mechanisms for cellular uptake and intracellular processing of NAG causing increased NAG release into the tubular lumen. 4. The absence of changes in renal cellular morphology indicates that the excessive renal losses of calcium and magnesium were an effect of gentamicin per se and not the result of underlying renal tubular injury. The renal effects described in this paper were apparent after administration of relatively low total drug doses, and with plasma concentrations calculated to be within the clinical range. These findings suggest that disturbances of plasma electrolyte homeostasis could occur in the absence of overt renal injury in patients receiving aminoglycoside antibiotics.

Ketorolac for early postoperative analgesia

STUDY OBJECTIVE

To determine the efficacy and speed of onset of analgesia of a single dose of intravenous (IV) or intramuscular (IM) ketorolac tromethamine following major orthopedic surgery.

STUDY DESIGN

Double-blind, randomized, placebo-controlled trial.

SETTING

A district general hospital in England.

PATIENTS

112 patients aged 18 to 80 years suffering moderate or severe pain following orthopedic surgery.

INTERVENTIONS

Patients were randomized to receive 30 mg ketorolac IV, 30 mg ketorolac IM, or placebo following surgery.

MEASUREMENTS AND MAIN RESULTS

Verbal pain intensity scores were performed prior to admission to the study, then frequently for the first 45 minutes following administration of study medication, and subsequently at hourly intervals. Times to request for further analgesia were noted. Patient assessment of overall acceptability and pain relief of the study medication was recorded. There was no statistical difference in speed of onset of analgesia between the ketorolac groups and placebo. Median (range) times to first analgesic following study drugs were: ketorolac IV 45 minutes (9 to 1440 minutes), ketorolac IM 34 minutes (10 to 1440 minutes), placebo 24 minutes (10 to 615 minutes). There was a statistically significant difference between the ketorolac groups and placebo (ketorolac IV vs. placebo, p < 0.01; ketorolac IM vs. placebo, p = 0.03). Patient assessment of overall acceptability and pain relief was significantly better for IV ketorolac compared with placebo (p < 0.01). By 6 hours, 78% of the IV ketorolac group and 95% of the IM ketorolac and placebo groups required further analgesia.

CONCLUSIONS

Despite high patient acceptability compared with placebo, the use of ketorolac as the sole analgesic failed to control postoperative pain following major orthopedic surgery. IV administration of ketorolac conferred no advantages over the IM route with regard to efficacy or speed of onset.

Preliminary clinical trials of a computer-based cardiac arrest alarm

The use of a high reliability cardiac arrest alarm utilising the continuously monitored values of patient heart rate and mean arterial blood pressure is described, based on a sample of 167 patients monitored for a total of 5116 h. The analogue heart rate and mean blood pressure signals are sampled at 1 s intervals, and a smoothing algorithm is applied to each of the resulting series which rejects artefacts, and identifies slope and step changes in each. Certain combinations of events in the 2 series, occurring within a preset time window, determine whether a cardiac arrest alarm or warning signal should be activated by the system. A total of 30 acute events occurring in 14 patients during the course of the study were each identified within 10 s. No cardiac arrest event was misdiagnosed by the algorithm during the period of the study. The algorithm also generates warnings which may have predictive value, and which will be the subject of further research. A final false alarm rate of about 1/200 h of monitoring was observed in adults (1/50 h in children), with evidence that these rates could be substantially improved.

Central station data displays: an experimental evaluation of observer performance. Part 2: Factors affecting performance, and a comparison of analogue and digital data

16 experienced ICU nurses monitored simulated central station VDU displays for the occurrence of ectopic beats and for signs of deterioration in general cardiovascular status. Each period of monitoring lasted for 1 h, and on separate occasions each nurse monitored 1, 2, 4 or 6 displays simultaneously. For primary clinical tasks, the data showed that the nurses' performance improved with each test. The identification of ventricular ectopic beats (VEBs) improved within the 1 h of each test except when 6 screens were being viewed simultaneously, with a similar result for the identification of deterioration of cardiovascular status. The nurses showed a marked preference for analogue signals over digits for the identification of VEBs. The highest priority clinical task was the identification of deteriorating cardiovascular status. When this task was performed efficiently less attention was given to minor tasks, and the nurse rated herself as very tired.

Central station data displays: an experimental evaluation of observer performance. Part 1: Number of displays and observation time

16 experienced ICU nurses monitored simulated central station VDU displays for the occurrence of ectopic beats and for signs of deterioration in general cardiovascular status. Each period of monitoring lasted for 1 h, and on separate occasions each nurse monitored 1, 2, 4 or 6 displays simultaneously. As the number of observed screens increased, performance declined significantly, with reduced identifications of discrete events (e.g., ectopic beat detections), and with increased delays in determining a deterioration in cardiovascular status; in addition, a secondary task was less accurately and efficiently performed, and the nurses tended to become increasingly fatigued. Efficient observing was maintained over the 1 h monitoring period, but only at considerable cost in terms of fatigue and a loss of alertness. The results suggest that there may be restrictions in the use of complex central station facilities at first-line observation posts for patient care.

A sampling study of bedside nursing activity in a cardiac surgical intensive care unit. Part 2. The effect of time and shift on the nursing workload

For a selected group of 17 patients following cardiac surgery, 33 discrete elements of nursing workload have been defined, and the nurse's bedside activities logged at 1 min intervals throughout the 24 h immediately following the patient's return from the operating theatre. It is possible to identify three broad types of activity undertaken by the bedside nurse; technical nursing care (Type 1), intermittent nursing care (Type 2), and the balance of the nurse's time, largely concerned with observation and liaison with other staff--learning activities (Type 3). The time devoted to technical nursing care reduces significantly over the patient's first 24 h in the ward. On the other hand the time devoted to intermittent nursing care and learning activities is shown to be shift dependent. The effect of the efficient utilisation of computer technology is estimated, and it is demonstrated that the implementation of such technology would result in the expansion of the time available for the nurse to observe the patient. The potential benefits and drawbacks of this are discussed.

A sampling study of bedside nursing activity in a cardiac surgical intensive care unit. Part 1: Analysis of the elements of activity in the nursing workload, and its variation with patient age group and pathology

For a selected group of 17 patients following cardiac surgery, 33 discrete elements of nursing workload have been defined. It was possible to identify 3 broad types of activity undertaken by the bedside nurse; technical nursing care (Type 1), intermittent nursing care (Type 2), and learning activities (Type 3). The latter is the balance of the nurses time which is largely concerned with observation and liaison with other staff. The 17 patients comprised 4 groups of pathologies, 2 each representative of the adult and paediatric workload. The primary bedside nurse performs virtually all of the Type 1 activities, recruiting the assistance of a secondary nurse principally to change the patients' posture (a Type 2 activity). The only practically significant period of time spent by the secondary nurse is in clinical discussion with the bedside nurse, largely at change of shift. Statistically significant differences in bedside nursing activities between age groups can be explained by the relative physical size of the patients and equipment. However the nurse maintains a higher level of awareness with shorter periods of inattention when nursing children. A greater number of significant differences between pathologies were found within the paediatric group of patients; this may indicate that a broader spectrum of such differences is to be found in this age group. An estimate was made of the impact of computer technology on the nurse's bedside workload.