CT colonography: interpretative performance in a non-academic environment

AIM: To investigate interpretative accuracy and reporting time for radiologists performing computed tomography (CT) colonography in day-to-day non-academic clinical practice. MATERIALS AND METHODS: Thirteen radiologists from seven centres, who were reporting CT colonography in non-academic daily clinical practice, interpreted a dataset of 15 colonoscopically validated cases in a controlled environment. Ten cases had either a cancer or polyp >10mm; one case had a medium polyp and four were normal. Correct case categorization and interpretation times were compared using analysis of variance to aggregated results obtained from both experienced observers and observers recently trained using 50 cases, working in an academic environment. The effect of experience was determined using Spearman's rank correlation. RESULTS: Individual accuracy was highly variable, range 53% (95% CI 27-79%) to 93% (95% CI 68-100%). Mean accuracy overall was significantly inferior to experienced radiologists (mean 75 versus 88%, p=0.04) but not significantly different from recently trained radiologists (p=0.48). Interpretation time was not significantly different to experienced readers (mean 12.4 min versus 11.7, p=0.74), but shorter than recently trained radiologists (p=0.05). There was a significant, positive, linear correlation between prior experience and accuracy (p<0.001) with no plateau. CONCLUSION: Accuracy for sub-specialist radiologists working in a non-academic environment is, on average, equivalent to radiologists trained using 50 cases. However, there is wide variability in individual performance, which generally falls short of the average performance suggested by meta-analysis of published data. Experience improves accuracy, but alone is insufficient to determine competence.     

Ethnical and clinical aspects of chronic lymphocytic leukemia in Israel: a survey on 288 patients.

The ethnic distribution of 288 patients with chronic lymphocytic leukemia (CLL) from five medical centers in Israel during the decade 1960--1970 was investigated as well as other features of the disease. 80.5% of the patients were of East European descent, 14.5% originated from Asia and Africa and 5% were born in Israel. Based on the ethnic distribution of the elderly population of Israel during the above period, it is suggested that CLL occurs more frequently in European-born Jews than in Asian and African Jews. A low occurrence of Coombs positive hemolytic anemia was revealed, amounting to 7.2% of the patients. Of 68 patients who underwent serum immunoglobulin studies, up to 74% exhibited deficiency of at least one type of immunoglobulin. Low levels of IgA were encountered in 61.2%, IgM in 51.5% and IgG in 29.5% of the patients. 26 of 206 patients with CLL (12.5%), all of East European origin, had an additional primary malignant tumor, cancer of the skin and breast being the most frequent associated malignancies. In 6 patients of the 26, two additional neoplasms were diagnosed. Hypogammaglobulinemia was more frequent in patients with additional primary malignant tumors and in patients with advanced disease. The possible causes for the ethnic distribution of CLL in Israil as well as of other tumors are discussed.     

Cerebral oxygenation decreases but does not impair performance during self-paced,strenuous exercise

Aim: The reduction in cerebral oxygenation (Cox) is associated with the cessation of exercise during constant work rate and incremental tests to exhaustion. Yet in exercises of this nature, ecological validity is limited due to work rate being either fully or partly dictated by the protocol, and it is unknown whether cerebral deoxygenation also occurs during self-paced exercise. Here, we investigated the cerebral haemodynamics during a 5-km running time trial in trained runners. Methods: Rating of perceived exertion (RPE) and surface electromyogram (EMG) of lower limb muscles were recorded every 0.5 km. Changes in Cox (prefrontal lobe) were monitored via near-infrared spectroscopy through concentration changes in oxy- and deoxyhaemoglobin (Δ[O₂Hb], Δ[HHb]). Changes in total Hb were calculated (Δ[THb] = Δ[O₂Hb] + Δ[HHb]) and used as an index of change in regional blood volume. Results: During the trial, RPE increased from 6.6 ± 0.6 to 19.1 ± 0.7 indicating maximal exertion. Cox rose from baseline to 2.5 km (↑Δ[O₂Hb], ↑Δ[HHb], ↑Δ[THb]), remained constant between 2.5 and 4.5 km, and fell from 4.5 to 5 km (↓Δ[O₂Hb], ↑Δ[HHb], ↔Δ[THb]). Interestingly, the drop in Cox at the end of the trial coincided with a final end spurt in treadmill speed and concomitant increase in skeletal muscle recruitment (as revealed by higher lower limb EMG). Conclusion: Results confirm the large tolerance for change in Cox during exercise at sea level, yet further indicate that, in conditions of self-selected work rate, cerebral deoxygenation remains within a range that does not hinder strenuous exercise performance.     

Effect of negative air ions on the potential for bacterial contamination of plastic medical equipment

Background  

In recent years there has been renewed interest in the use of air ionizers to control the spread of infection in hospitals and a number of researchers have investigated the biocidal action of ions in both air and nitrogen. By comparison, the physical action of air ions on bacterial dissemination and deposition has largely been ignored. However, there is clinical evidence that air ions might play an important role in preventing the transmission of Acinetobacter infection. Although the reasons for this are unclear, it is hypothesized that a physical effect may be responsible: the production of air ions may negatively charge items of plastic medical equipment so that they repel, rather than attract, airborne bacteria. By negatively charging both particles in the air and items of plastic equipment, the ionizers minimize electrostatic deposition on these items. In so doing they may help to interrupt the transmission of Acinetobacter infection in certain healthcare settings such as intensive care units.     

Pulmonary and systemic consequences of localized acid aspiration

Acid aspiration may recruit a generalized inflammatory reaction that can potentiate the local injury. After surgical isolation of bronchi in a group of 15 dogs, 1 milliliter per kilogram of 0.37 normal hydrochloric acid was instilled into either side. After five minutes, platelet and white blood cell counts fell to 10,000 and 1,000 per cubic millimeter (p less than 0.05). Platelet aggregates were noted in blood smears. 111Indium-platelet activity doubled over both the aspirated and nonaspirated lung (p less than 0.05). Physiologic dead space rose from 18 to 67 per cent and to 46 per cent in the aspirated and nonaspirated lung (p less than 0.05). Physiologic shunt increased from 12 to 47 per cent and to 43 per cent (p less than 0.05) on the two sides. Plasma thromboxane B2 levels at 30 minutes rose from 0.28 to 0.93 nanograms per milliliter (p less than 0.05). Edema fluid from the aspirated lung had thromboxane B2 values of 2.87 nanograms per milliliter, indicating pulmonary synthesis. Within five minutes of aspiration, systemic effects were prominent; mean arterial pressure fell from 114 to 46 milliliters of mercury (p less than 0.05), and the cardiac index fell 24 per cent from 106 to 81 milliliters per kilogram per minute (p less than 0.05) along with an 18 per cent decrease in contractility of a rat papillary muscle bathed in plasma from the aspirated dog. Mean pulmonary arterial pressure rose from 12 to 18 millimeters of mercury (p less than 0.05). Despite fluid infusion at 36 milliliters per kilogram per hour to keep wedge pressure constant at 5.5 millimeters of mercury, and sampling of one-third the blood volume, hemoglobin concentration rose 0.9 grams per cent (p less than 0.05) indicating increased microvascular permeability. At autopsy, the aspirated and nonaspirated lung were indistinguishable with congestion, interstitial hemorrhage, and white blood cell infiltrates. Systemic organs showed vascular congestion and edema. These data demonstrate that local aspiration leads to generalized inflammatory sequelae with cardiopulmonary failure.     

A simplified method for repeated nasotracheal suction

The use of a Tiemann curved tip urethral catheter for repeated nasotracheal suction in 120 instances of postoperative pulmonary complications was proved to be more efficient than the use of a regular suction catheter. The curved tip is better adapted to the anatomy of the nasotracheobronchial tract and allows easy selective catheterization of the trachea and major bronchi.     

A magnetization transfer analysis of the thalamus in schizophrenia

The authors investigated the thalamus in schizophrenia by using magnetization transfer ratio (MTR), a novel structural magnetic resonance technique sensitive to subtle neuropathological abnormalities. The dorsomedial nucleus (DMN) and pulvinar were selected because of their connections to limbic, prefrontal, and temporal regions, putatively relevant in schizophrenia. Volume (intracranial; thalamic) and MTR (whole thalamus; DMN; pulvinar) were determined in 25 patients with chronic schizophrenia by DSM-IV criteria and 25 control subjects. There were no significant differences between patients and control subjects in thalamic volume (corrected for intracranial volume) or MTR in whole thalamus, DMN, or pulvinar. No volumetric or MTR abnormalities could be detected in the thalamus of patients with schizophrenia. The findings suggest that abnormalities, if present, are very subtle and beyond the power of resolution of these techniques.     

Training techniques to improve endurance exercise performances

In previously untrained individuals, endurance training improves peak oxygen uptake (VO2peak), increases capillary density of working muscle, raises blood volume and decreases heart rate during exercise at the same absolute intensity. In contrast, sprint training has a greater effect on muscle glyco(geno)lytic capacity than on muscle mitochondrial content. Sprint training invariably raises the activity of one or more of the muscle glyco(geno)lytic or related enzymes and enhances sarcolemmal lactate transport capacity. Some groups have also reported that sprint training transforms muscle fibre types, but these data are conflicting and not supported by any consistent alteration in sarcoplasmic reticulum Ca2+ ATPase activity or muscle physicochemical H+ buffering capacity. While the adaptations to training have been studied extensively in previously sedentary individuals, far less is known about the responses to high-intensity interval training (HIT) in already highly trained athletes. Only one group has systematically studied the reported benefits of HIT before competition. They found that >or=6 HIT sessions, was sufficient to maximally increase peak work rate (W(peak)) values and simulated 40 km time-trial (TT(40)) speeds of competitive cyclists by 4 to 5% and 3.0 to 3.5%, respectively. Maximum 3.0 to 3.5% improvements in TT(40) cycle rides at 75 to 80% of W(peak) after HIT consisting of 4- to 5-minute rides at 80 to 85% of W(peak) supported the idea that athletes should train for competition at exercise intensities specific to their event. The optimum reduction or 'taper' in intense training to recover from exhaustive exercise before a competition is poorly understood. Most studies have shown that 20 to 80% single-step reductions in training volume over 1 to 4 weeks have little effect on exercise performance, and that it is more important to maintain training intensity than training volume. Progressive 30 to 75% reductions in pool training volume over 2 to 4 weeks have been shown to improve swimming performances by 2 to 3%. Equally rapid exponential tapers improved 5 km running times by up to 6%. We found that a 50% single-step reduction in HIT at 70% of W(peak) produced peak approximately 6% improvements in simulated 100 km time-trial performances after 2 weeks. It is possible that the optimum taper depends on the intensity of the athletes' preceding training and their need to recover from exhaustive exercise to compete. How the optimum duration of a taper is influenced by preceding training intensity and percentage reduction in training volume warrants investigation.     

Role of protein and carbohydrate sources on acute appetite responses in lean and overweight men

Dietary protein induces greater satiety compared with carbohydrate in lean subjects, which may involve appetite-regulatory gut hormones. Little is known about the duration of effect, influence of protein and carbohydrate source and relevance to non-lean individuals. We compared the effect of various dietary proteins and carbohydrates on post-prandial appetite ratings, ad libitum energy intake (EI) and appetite hormones in lean and overweight men. Three randomised double-blinded cross-over studies examined appetite response (appetite ratings, ghrelin, glucagon-like peptide-1 (GLP-1) and cholecystokinin) to liquid preloads over three to four hours followed by a buffet meal to assess ad libitum EI. The 1-MJ preloads contained ∼55 g of protein (whey, casein, soy and gluten), carbohydrate (glucose, lactose and fructose) or combined whey/fructose. EI was 10% higher following glucose preloads compared with protein preloads, observed at three hours but not four hours. Protein ingestion was followed by prolonged elevation of cholecystokinin and GLP-1 (two hours) and suppression of ghrelin (three to four hours) compared with glucose and independent of protein type. Replacing some whey with fructose attenuated the effect of protein on these hormones. Treatment effects on EI and appetite hormones were independent of bodyweight status, despite higher GLP-1 and lower ghrelin in overweight subjects. Protein-rich liquid preloads reduce EI over three hours in overweight men compared with glucose. These findings suggest a potential application for protein-rich drinks and/or foods to facilitate reduced EI. Future studies should explore additional dietary manipulations that may enhance this relationship, and confirm these effects within the context of energy-restricted dietary patterns.